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  • Springer Nature  (76,839)
  • Wiley-Blackwell  (49,867)
  • 2020-2023  (36)
  • 1960-1964  (49,393)
  • 1950-1954  (25,957)
  • 1935-1939  (26,509)
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  • 1
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    Deep water inflow slowed offshore expansion of the West Antarctic Ice Sheet at the Eocene-Oligocene transition (2022)
    Springer Nature
    In:  EPIC3Nature Communications Earth & Environment, Springer Nature, 3(1)
    Details
    Publication Date: 2022-02-21
    Description: The stability of the West Antarctic Ice Sheet is threatened by the incursion of warm Circumpolar Deepwater which flows southwards via cross-shelf troughs towards the coast there melting ice shelves. However, the onset of this oceanic forcing on the development and evolution of the West Antarctic Ice Sheet remains poorly understood. Here, we use single- and multichannel seismic reflection profiles to investigate the architecture of a sediment body on the shelf of the Amundsen Sea Embayment. We estimate the formation age of this sediment body to be around the Eocene-Oligocene Transition and find that it possesses the geometry and depositional pattern of a plastered sediment drift. We suggest this indicates a southward inflow of deep water which probably supplied heat and, thus, prevented West Antarctic Ice Sheet advance beyond the coast at this time. We conclude that the West Antarctic Ice Sheet has likely experienced a strong oceanic influence on its dynamics since its initial formation.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 2
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    Catching the Main Ethiopian Rift evolving towards plate divergence (2022)
    Springer Nature
    Details
    Publication Date: 2022-02-11
    Description: Magmatism accompanies rifting along divergent plate boundaries, although its role before continental breakup remains poorly understood. For example, the magma-assisted Northern Main Ethiopian Rift (NMER) lacks current volcanism and clear tectono-magmatic relationships with its contiguous rift portions. Here we define its magmatic behaviour, identifying the most recent eruptive fissures (EF) whose aphyric basalts have a higher Ti content than those of older monogenetic scoria cones (MSC), which are porphyritic and plagioclase-dominated. Despite these differences, calculations highlight a similar parental melt for EF and MSC products, suggesting only a different evolutionary history after melt generation. While MSC magmas underwent a further step of storage at intermediate crustal levels, EF magmas rose directly from the base of the crust without contamination, even below older polygenetic volcanoes, suggesting rapid propagation of transcrustal dikes across solidified magma chambers. Whether this recent condition in the NMER is stable or transient, it indicates a transition from central polygenetic to linear fissure volcanism, indicative of increased tensile conditions and volcanism directly fed from the base of the crust, suggesting transition towards mature rifting.
    Description: Published
    Description: 21821
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
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    Energy threshold changes in volcanic activity at Mt. Etna (Italy) inferred from volcanic tremor (2022)
    Springer Nature
    Details
    Publication Date: 2022-10-28
    Description: From the 2010s on, pattern classification has proven an effective method for flagging alerts of volcano unrest before eruptive activity at Mt. Etna, Italy. The analysis has been applied online to volcanic tremor data, and has supported the surveillance activity of the volcano that provides timely information to Civil Protection and other authorities. However, after declaring an alert, no one knows how long the volcano unrest will last and if a climactic eruptive activity will actually begin. These are critical aspects when considering the effects of a prolonged state of alert. An example of longstanding unrest is related to the Christmas Eve eruption in 2018, which was heralded by several months of almost continuous Strombolian activity. Here, we discuss the usage of thresholds to detect conditions leading to paroxysmal activity, and the challenges associated with defining such thresholds, leveraging a dataset of 52 episodes of lava fountains occurring in 2021. We were able to identify conservative settings regarding the thresholds, allowing for an early warning of impending paroxysm in almost all cases (circa 85% for the first 4 months in 2021, and over 90% for the whole year). The chosen thresholds also proved useful to predict that a paroxysmal activity was about to end. Such information provides reliable numbers for volcanologists for their assessments, based on visual information, which may not be available in bad weather or cloudy conditions.
    Description: Project IMPACT (A multidisciplinary Insight on the kinematics and dynamics of Magmatic Processes at Mt. Etna Aimed at identifying preCursor phenomena and developing early warning sysTems). IMPACT belongs to the Progetti Dipartimentali INGV [DIP7], https://progetti.ingv.it/index.php/it/progetti-dipartimentali/vulcani/impact#informazioni-sul-progetto.
    Description: Published
    Description: 17895
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Volcanic tremor ; Volcano monitoring ; Pattern recognition ; Self Organizing maps ; Fuzzy clustering ; Mt. Etna ; 04.06. Seismology ; 04.08. Volcanology ; 05.01. Computational geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
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    Evidence for late glacial oceanic carbon redistribution and discharge from the Pacific Southern Ocean (2022)
    Springer Nature
    In:  EPIC3Nature Communications, Springer Nature, 13, 12 p., ISSN: 2041-1723
    Details
    Publication Date: 2022-11-14
    Description: Southern Ocean deep-water circulation plays an important role in the global carbon cycle. On geological time-scales, upwelling along the Chilean continental margin likely contributed to the deglacial atmospheric carbon dioxide rise, but little quantitative evidence exists of carbon storage. Here, we use a new X-ray Micro-Computer-Tomography method to assess foraminiferal test dissolution as proxy for paleo-carbonate ion concentrations [CO3^2−]. Our subantarctic Southeast Pacific sediment core depth transect shows significant deep-water [CO3^2−] variations during the Last Glacial Maximum and Deglaciation (10 – 22 ka BP). We provide evidence for an increase in [CO3^2−] during the early deglacial period (15-19 ka BP), followed by a ca. 40 µmol kg^-1 reduction in Lower Circumpolar Deepwater (CDW). This decreased Pacific to Atlantic export of low-carbon CDW contributed to significantly lowered carbon storage within the Southern Ocean, highlighting the importance of a dynamic Pacific–Southern Ocean deep-water reconfiguration for shaping late-glacial oceanic carbon storage, and subsequent deglacial oceanic-atmospheric CO2 transfer.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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  • 5
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    Southern Ocean biogenic blooms freezing-in Oligocene colder climates (2022)
    Springer Nature
    In:  EPIC3Nature Communications, Springer Nature, 13(1), pp. 1-10, ISSN: 2041-1723
    Details
    Publication Date: 2022-11-24
    Description: 〈jats:title〉Abstract〈/jats:title〉〈jats:p〉Crossing a key atmospheric CO〈jats:sub〉2〈/jats:sub〉 threshold triggered a fundamental global climate reorganisation ~34 million years ago (Ma) establishing permanent Antarctic ice sheets. Curiously, a more dramatic CO〈jats:sub〉2〈/jats:sub〉 decline (~800–400 ppm by the Early Oligocene(~27 Ma)), postdates initial ice sheet expansion but the mechanisms driving this later, rapid drop in atmospheric carbon during the early Oligocene remains elusive and controversial. Here we use marine seismic reflection and borehole data to reveal an unprecedented accumulation of early Oligocene strata (up to 2.2 km thick over 1500 × 500 km) with a major biogenic component in the Australian Southern Ocean. High-resolution ocean simulations demonstrate that a tectonically-driven, one-off reorganisation of ocean currents, caused a unique period where current instability coincided with high nutrient input from the Antarctic continent. This unrepeated and short-lived environment favoured extreme bioproductivity and enhanced sediment burial. The size and rapid accumulation of this sediment package potentially holds ~1.067 × 10〈jats:sup〉15〈/jats:sup〉 kg of the ‘missing carbon’ sequestered during the decline from an Eocene high CO〈jats:sub〉2〈/jats:sub〉-world to a mid-Oligocene medium CO〈jats:sub〉2〈/jats:sub〉-world, highlighting the exceptional role of the Southern Ocean in modulating long-term climate.〈/jats:p〉
    Repository Name: EPIC Alfred Wegener Institut
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  • 6
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    Environmental stability and phenotypic plasticity benefit the cold-water coral Desmophyllum dianthus in an acidified fjord (2022)
    Springer Nature
    In:  EPIC3Communications Biology, Springer Nature, 5(683)
    Details
    Publication Date: 2022-07-13
    Description: The stratified Chilean Comau Fjord sustains a dense population of the cold-water coral (CWC) Desmophyllum dianthus in aragonite supersaturated shallow and aragonite under- saturated deep water. This provides a rare opportunity to evaluate CWC fitness trade-offs in response to physico-chemical drivers and their variability. Here, we combined year-long reciprocal transplantation experiments along natural oceanographic gradients with an in situ assessment of CWC fitness. Following transplantation, corals acclimated fast to the novel environment with no discernible difference between native and novel (i.e. cross-transplanted) corals, demonstrating high phenotypic plasticity. Surprisingly, corals exposed to lowest ara- gonite saturation (Ωarag 〈 1) and temperature (T 〈 12.0 °C), but stable environmental condi- tions, at the deep station grew fastest and expressed the fittest phenotype. We found an inverse relationship between CWC fitness and environmental variability and propose to consider the high frequency fluctuations of abiotic and biotic factors to better predict the future of CWCs in a changing ocean.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 7
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    Mid-Pliocene El Niño/Southern Oscillation suppressed by Pacific intertropical convergence zone shift (2022)
    Springer Nature
    In:  EPIC3Nature Geoscience, Springer Nature, ISSN: 1752-0908
    Details
    Publication Date: 2022-08-16
    Description: The El Niño/Southern Oscillation (ENSO), the dominant driver of year-to-year climate variability in the equatorial Pacific Ocean, impacts climate pattern across the globe. However, the response of the ENSO system to past and potential future temperature increases is not fully understood. Here we investigate ENSO variability in the warmer climate of the mid-Pliocene (~3.0–3.3 Ma), when surface temperatures were ~2–3 °C above modern values, in a large ensemble of climate models—the Pliocene Model Intercomparison Project. We show that the ensemble consistently suggests a weakening of ENSO variability, with a mean reduction of 25% (±16%). We further show that shifts in the equatorial Pacific mean state cannot fully explain these changes. Instead, ENSO was suppressed by a series of off-equatorial processes triggered by a northward displacement of the Pacific intertropical convergence zone: weakened convective feedback and intensified Southern Hemisphere circulation, which inhibit various processes that initiate ENSO. The connection between the climatological intertropical convergence zone position and ENSO we find in the past is expected to operate in our warming world with important ramifications for ENSO variability.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 8
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    Sea ice surface temperatures from helicopter-borne thermal infrared imaging during the MOSAiC expedition (2022)
    Springer Nature
    In:  EPIC3Scientific Data, Springer Nature, 9(1), ISSN: 2052-4463
    Details
    Publication Date: 2022-06-27
    Description: The sea ice surface temperature is important to understand the Arctic winter heat budget. We conducted 35 helicopter flights with an infrared camera in winter 2019/2020 during the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The flights were performed from a local, 5 to 10 km scale up to a regional, 20 to 40 km scale. The infrared camera recorded thermal infrared brightness temperatures, which we converted to surface temperatures. More than 150000 images from all flights can be investigated individually. As an advanced data product, we created surface temperature maps for every flight with a 1 m resolution. We corrected image gradients, applied an ice drift correction, georeferenced all pixels, and corrected the surface temperature by its natural temporal drift, which results in time-fixed surface temperature maps for a consistent analysis of one flight. The temporal and spatial variability of sea ice characteristics is an important contribution to an increased understanding of the Arctic heat budget and, in particular, for the validation of satellite products.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 9
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    Diversity and origins of bacterial and archaeal viruses on sinking particles reaching the abyssal ocean (2022)
    Springer Nature
    Details
    Publication Date: 2022-06-14
    Description: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Luo, E., Leu, A. O., Eppley, J. M., Karl, D. M., & DeLong, E. F. Diversity and origins of bacterial and archaeal viruses on sinking particles reaching the abyssal ocean. ISME Journal, 16, : 1627–1635, https://doi.org/10.1038/s41396-022-01202-1.
    Description: Sinking particles and particle-associated microbes influence global biogeochemistry through particulate matter export from the surface to the deep ocean. Despite ongoing studies of particle-associated microbes, viruses in these habitats remain largely unexplored. Whether, where, and which viruses might contribute to particle production and export remain open to investigation. In this study, we analyzed 857 virus population genomes associated with sinking particles collected over three years in sediment traps moored at 4000 m in the North Pacific Subtropical Gyre. Particle-associated viruses here were linked to cellular hosts through matches to bacterial and archaeal metagenome-assembled genome (MAG)-encoded prophages or CRISPR spacers, identifying novel viruses infecting presumptive deep-sea bacteria such as Colwellia, Moritella, and Shewanella. We also identified lytic viruses whose abundances correlated with particulate carbon flux and/or were exported from the photic to abyssal ocean, including cyanophages. Our data are consistent with some of the predicted outcomes of the viral shuttle hypothesis, and further suggest that viral lysis of both autotrophic and heterotrophic prokaryotes may play a role in carbon export. Our analyses revealed the diversity and origins of prevalent viruses found on deep-sea sinking particles and identified prospective viral groups for future investigation into processes that govern particle export in the open ocean.
    Description: This project is funded by grants from the Simons Foundation (#329108 to EFD and DMK, #721223 to EFD, and #721252 to DMK) and the Gordon and Betty Moore Foundation (GBMF3777 to EFD and GBMF3794 to DMK). Partial support for EL was provided by the Natural Sciences and Engineering Research Council of Canada (PGSD3-487490-2016).
    Repository Name: Woods Hole Open Access Server
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  • 10
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    Intracellular nitrate storage by diatoms can be an important nitrogen pool in freshwater and marine ecosystems (2022)
    Springer Nature
    In:  EPIC3Communications Earth & Environment, Springer Nature, 3(1), ISSN: 2662-4435
    Details
    Publication Date: 2022-07-06
    Description: Identifying and quantifying nitrogen pools is essential for understanding the nitrogen cycle in aquatic ecosystems. The ubiquitous diatoms represent an overlooked nitrate pool as they can accumulate nitrate intracellularly and utilize it for nitrogen assimilation, dissipation of excess photosynthetic energy, and Dissimilatory Nitrate Reduction to Ammonium (DNRA). Here, we document the global co-occurrence of diatoms and intracellular nitrate in phototrophic microbial communities in freshwater (n = 69), coastal (n = 44), and open marine (n = 4) habitats. Diatom abundance and total intracellular nitrate contents in water columns, sediments, microbial mats, and epilithic biofilms were highly significantly correlated. In contrast, diatom community composition had only a marginal influence on total intracellular nitrate contents. Nitrate concentrations inside diatom cells exceeded ambient nitrate concentrations ∼100–4000-fold. The collective intracellular nitrate pool of the diatom community accounted for 〈1% of total nitrate in pelagic habitats and 65–95% in benthic habitats. Accordingly, nitrate-storing diatoms are emerging as significant contributors to benthic nitrogen cycling, in particular through Dissimilatory Nitrate Reduction to Ammonium activity under anoxic conditions.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed , info:eu-repo/semantics/article
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  • 11
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    Exploring Employee Perceptions towards Smart Working during the COVID-19 Pandemic: a Comparative Analysis of Two Italian Public Research Organizations (2021)
    Springer Nature
    Details
    Publication Date: 2022-03-16
    Description: Of all the socio-economic changes caused by the Covid-19 pandemic, the disruption to workforce organizations will probably leave the largest indelible mark. The way work will be organized in the future will be closely linked to the experience of work-ing under the same institution’s response to the pandemic. This paper aims to fill the gap in knowledge about smart working (SW) in public organizations, with a focus on the experience of the employees of two Italian research organizations, CNR and INGV. Analysing primary data, it explored and assessed how SW had been experi-enced following the implementation of governmental measures aimed at limiting the spread of COVID-19
    Description: Published
    Description: 815–833
    Description: 2TM. Divulgazione Scientifica
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
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    Combining audio and visual displays to highlight temporal and spatial seismic patterns (2021)
    Springer Nature
    Details
    Publication Date: 2022-03-16
    Description: Data visualization, and to a lesser extent data sonification, are classic tools to the scientific community. However, these two approaches are very rarely combined, although they are highly complementary: our visual system is good at recognizing spatial patterns, whereas our auditory system is better tuned for temporal patterns. In this article, data representation methods are proposed that combine visualization, sonification, and spatial audio techniques, in order to optimize the user’s perception of spatial and temporal patterns in a single display, to increase the feeling of immersion, and to take advantage of multimodal integration mechanisms. Three seismic data sets are used to illustrate the methods, covering different physical phenomena, time scales, spatial distributions, and spatio-temporal dynamics. The methods are adapted to the specificities of each data set, and to the amount of information that the designer wants to display. This leads to further developments, namely the use of audification with two time scales, the switch from pure audification to time-modulated noise, and the switch from pure audification to sonic icons. First user feedback from live demonstrations indicates that the methods presented in this article seem to enhance the perception of spatio-temporal patterns, which is a key parameter to the understanding of seismically active systems, and a step towards apprehending the processes that drive this activity.
    Description: Published
    Description: 125–142
    Description: 7T. Variazioni delle caratteristiche crostali e "precursori"
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
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    Short-term clustering modeling of seismicity in Eastern Aegean Sea (Greece): a retrospective forecast test of the 2017 Mw = 6.4 Lesvos, 2017 Mw = 6.6 Kos and 2020 Mw = 7.0 Samos earthquake sequences (2021)
    Springer Nature
    Details
    Publication Date: 2021-11-03
    Description: Short-term earthquake clustering properties in the Eastern Aegean Sea (Greece) area investigated through the application of an epidemic type stochastic model (Epidemic Type Earthquake Sequence; ETES). The computations are performed in an earthquake catalog covering the period 2008 to 2020 and including 2332 events with a completeness threshold of Mc = 3.1 and separated into two subcatalogs. The first subcatalog is employed for the learning period, which is between 2008/01/01 and 2016/12/31 (N = 1197 earthquakes), and used for the model’s parameters estimation. The second subcatalog from 2017/01/01 to 2020/11/10 (1135 earthquakes), in which the sequences of 2017 Mw = 6.4 Lesvos, 2017 Mw = 6.6 Kos and 2020 Mw = 7.0 Samos main shocks are included, and used for a retrospective forecast testing based on the constructed model. The estimated model parameters imply a swarm like behavior, indicating the ability of earthquakes of small to moderate magnitude above Mc to produce their own offsprings, along with the stronger earthquakes. The retrospective evaluation of the model is examined in the three aftershock sequences, where lack of foreshocks resulted in low predictability of the mainshocks, with estimated daily probabilities around 10– 5. Immediately after the mainshocks occurrence the model adjusts with notable resemblance between the expected and observed aftershock rates, particularly for earthquakes with M ≥ 3.5.
    Description: Published
    Description: 1085–1099
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
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    Simulation of non-stationary stochastic ground motions based on recent Italian earthquakes (2021)
    Springer Nature
    Details
    Publication Date: 2021-11-29
    Description: This work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.
    Description: Published
    Description: 3287–3315
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
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  • 15
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    Insights on the Italian Seismic Network from location uncertainties (2021)
    Springer Nature
    Details
    Publication Date: 2021-12-01
    Description: Probabilistic earthquake locations provide confidence intervals for the hypocentre solutions such as errors encountered in the position, the origin time, and in magnitude. If the relationship of the parameters relative to the local arrangement of the seismic network is considered, such as the node distance, the number of stations, the seismic gap, and the quality of phase readings), the uncertainties can then provide insights on the location capability of the network. In this paper, we collect the earthquake data recorded from the Italian Seismic Network for a time span of 5 years. The data pertain to three different catalogues according to the progressive refinement phases of the location procedure: automatic location, revised location, and published location. By means of spatial analysis,we assess the distribution of the location-related and network-related estimators across the study area. These estimators are subsequently combined to assess the existence of spatial correlations at a local scale. The results indicate that the Italian network is generally able to provide robust locations at the national scale and for smaller earthquakes, and the elongated shape of Italy (and of its network) does not cause systematic bias in the locations. However, we highlight the existence of subregions in which the performance of the network is weaker. At present, a unique 2D, 3-layer velocity model is used for the earthquake location procedure, and this could represent the main limitation for the improvement of the locations. Therefore, the assessment of locally optimized velocity models is the priority for the homogenization and the improvement of the Italian Seismic Network performance.
    Description: Published
    Description: 1061–1076
    Description: 1IT. Reti di monitoraggio e sorveglianza
    Description: JCR Journal
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  • 16
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    New trenching results along the İznik segment of the central strand of the North Anatolian Fault (Turkey): an integration with preexisting data (2021)
    Springer Nature
    Details
    Publication Date: 2021-12-06
    Description: This paper provides a new contribution to the construction of the complex and fragmentary mosaic of the Late Holocene earthquakes history of the İznik segment of the central strand of the North Anatolian Fault (CNAF) in Turkey. The CNAF clearly displays lower dextral slip rates with respect to the northern strand however, surface rupturing and large damaging earthquakes (M 〉 7) occurred in the past, leaving clear signatures in the built and natural environments. The association of these historical events to specific earthquake sources (e.g., Gemlik, İznik, or Geyve fault segments) is still a matter of debate. We excavated two trenches across the İznik fault trace near Mustafali, a village about 10 km WSW of İznik where the morphological fault scarp was visible although modified by agricultural activities. Radiocarbon and TL dating on samples collected from the trenches show that the displaced deposits are very recent and span the past 2 millennia at most. Evidence for four surface faulting events was found in the Mustafali trenches. The integration of these results with historical data and previous paleoseismological data yields an updated Late Holocene history of surface-rupturing earthquakes along the İznik Fault in 1855, 740 (715), 362, and 121 CE. Evidence for the large M7 + historical earthquake dated 1419 CE generally attributed to this fault, was not found at any trench site along the İznik fault nor in the subaqueous record. This unfit between paleoseismological, stratigraphic, and historical data highlights one more time the urge for extensive paleoseismological trenching and offshore campaigns because of the high potential to solve the uncertainties on the seismogenic history (age, earthquake location, extent of the rupture and size) of this portion of NAFZ and especially on the attribution of historical earthquakes to the causative fault.
    Description: Published
    Description: 115–128
    Description: 2T. Deformazione crostale attiva
    Description: N/A or not JCR
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
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    Checking the site categorization criteria and amplification factors of the 2021 draft of Eurocode 8 Part 1–1 (2021)
    Springer Nature
    Details
    Publication Date: 2021-11-29
    Description: In this paper the site categorization criteria and the corresponding site amplification factors proposed in the 2021 draft of Part 1 of Eurocode 8 (2021-draft, CEN/TC250/SC8 Working Draft N1017) are first introduced and compared with the current version of Eurocode 8, as well as with site amplification factors from recent empirical ground motion prediction equations. Afterwards, these values are checked by two approaches. First, a wide dataset of strong motion records is built, where recording stations are classified according to 2021-draft, and the spectral amplifications are empirically estimated computing the site-to-site residuals from regional and global ground motion models for reference rock conditions. Second, a comprehensive parametric numerical study of one-dimensional (1D) site amplification is carried out, based on randomly generated shear-wave velocity profiles, classified according to the new criteria. A reasonably good agreement is found by both approaches. The most relevant discrepancies occur for the shallow soft soil conditions (soil category E) that, owing to the complex interaction of shear wave velocity, soil deposit thickness and frequency range of the excitation, show the largest scatter both in terms of records and of 1D numerical simulations. Furthermore, 1D numerical simulations for soft soil conditions tend to provide lower site amplification factors than 2021-draft, as well as lower than the corresponding site-to-site residuals from records, because of higher impact of non-linear (NL) site effects in the simulations. A site-specific study on NL effects at three KiK-net stations with a significantly large amount of high-intensity recorded ground motions gives support to the 2021-draft NL reduction factors, although the very limited number of recording stations allowing such analysis prevents deriving more general implications. In the presence of such controversial arguments, it is reasonable that a standard should adopt a prudent solution, with a limited reduction of the site amplification factors to account for NL soil response, while leaving the possibility to carry out site-specific estimations of such factors when sufficient information is available to model the ground strain dependency of local soil properties.
    Description: Published
    Description: 4199–4234
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Exceedance of design actions in epicentral areas: insights from the ShakeMap envelopes for the 2016–2017 central Italy sequence (2021)
    Springer Nature
    Details
    Publication Date: 2021-11-29
    Description: ShakeMap is the tool to evaluate the ground motion effect of earthquakes in vast areas. It is useful to delimit the zones where the shaking is expected to have been most significant, for civil defense rapid response. From the earthquake engineering point of view, it can be used to infer the seismic actions on the built environment to calibrate vulnerability models or to define the reconstruction policies based on observed damage vs shaking. In the case of long-lasting seismic sequences, it can be useful to develop ShakeMap envelopes, that is, maps of the largest ground intensity among those from the ShakeMap of (selected) events of a seismic sequence, to delimit areas where the effects of the whole sequence have been of structural engineering relevance. This study introduces ShakeMap envelopes and discusses them for the central Italy 2016–2017 seismic sequence. The specific goals of the study are: (i) to compare the envelopes and the ShakeMap of the main events of the sequence to make the case for sequence-based maps; (ii) to quantify the exceedance of design seismic actions based on the envelopes; (iii) to make envelopes available for further studies and the reconstruction planning; (iv) to gather insights on the (repeated) exceedance of design seismic actions at some sites. Results, which include considerations of uncertainty in ShakeMap, show that the sequence caused exceedance of design hazard in thousands of square kilometers. The most relevant effects of the sequence are, as expected, due to the mainshock, yet seismic actions larger than those enforced by the code for structural design are found also around the epicenters of the smaller magnitude events. At some locations, the succession of ground-shaking that has excited structures, provides insights on structural damage accumulation that has likely taken place; something that is not accounted for explicitly in modern seismic design. The envelopes developed are available as supplemental material.
    Description: Published
    Description: 5391–5414
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
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    Automatic inspection and analysis of digital waveform images by means of convolutional neural networks (2021)
    Springer Nature
    Details
    Publication Date: 2021-12-13
    Description: Analyzing seismic data to get information about earthquakes has always been a major task for seismologists and, more in general, for geophysicists. Recently, thanks to the technological development of observation systems, more and more data are available to perform such tasks. However, this data “grow up” makes “human possibility” of data processing more complex in terms of required efforts and time demanding. That is why new technological approaches such as artificial intelligence are becoming very popular and more and more exploited. In this paper, we explore the possibility of interpreting seismic waveform segments by means of pre-trained deep learning. More specifically, we apply convolutional networks to seismological waveforms recorded at local or regional distances without any pre-elaboration or filtering. We show that such an approach can be very successful in determining if an earthquake is “included” in the seismic wave image and in estimating the distance between the earthquake epicenter and the recording station.
    Description: Published
    Description: 1347–1359
    Description: 1T. Struttura della Terra
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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    Midlatitude climatology of the ionospheric equivalent slab thickness over two solar cycles (2021)
    Springer Nature
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    Publication Date: 2021-10-25
    Description: Themain climatological features of the ionospheric equivalent slab thickness (τ ) for the Northern hemispheremidlatitudes are analyzed. F2-layer peak electron density values recorded at three midlatitude ionospheric stations (Chilton 51.5° N, 0.6° W, U.K.; Roquetes 40.8° N, 0.5° E, Spain;Wallops Island 37.9° N, 75.5°W, USA) and vertical total electron content values from colocated ground-based Global Navigation Satellite System receivers are used to calculate a dataset of τ values for the last two solar cycles, considering only magnetically quiet periods. Results are presented both as grids of binned medians and as boxplots as a function of local time and month of the year, for different solar activity levels. Corresponding trends are first compared to those output by the midlatitude empirical model developed by Fox et al. (Radio Sci 26:429–438, 1991) and then discussed in the light of what is known so far. From this investigation, the strong need to implement an improved empirical model of τ has emerged. Both Space Weather and Space Geodesy applications might benefit from such model. Therefore, both the dataset and the methodology described in the paper represent a first fundamental step aimed at implementing an empirical climatological model of the ionospheric equivalent slab thickness. The study highlighted also that at midlatitudes τ shows the following main patterns: daytime values considerably smaller than nighttime ones (except in summer); well-defined maxima at solar terminator hours; a greater dispersion during nighttime and solar terminator hours; no clear and evident solar activity dependence.
    Description: Published
    Description: 124
    Description: 2A. Fisica dell'alta atmosfera
    Description: JCR Journal
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    Fracturing and healing of basaltic magmas during explosive volcanic eruptions (2021)
    Springer Nature
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    Publication Date: 2021-11-26
    Description: The eruption of basaltic magmas dominates explosive volcanism on Earth and other planets within the Solar System. The mechanism through which continuous magma fragments into volcanic particles is central in governing eruption dynamics and the ensuing hazards. However, the mechanism of fragmentation of basaltic magmas is still disputed, with both viscous and brittle mechanisms having been proposed. Here we carry out textural analysis of the products of ten eruptions from seven volcanoes by scanning electron microscopy. We find broken crystals surrounded by intact glass that testify to the brittle fragmentation of basaltic magmas during explosive activity worldwide. We then replicated the natural textures of broken crystals in laboratory experiments where variably crystallized basaltic melt was fragmented by rapid deformation. The experiments reveal that crystals are broken by the propagation of a network of fractures through magma, and that afterwards the fractures heal by viscous flow of the melt. Fracturing and healing affect gas mobility, stress distribution, and bubble and crystal size distributions in magma. Our results challenge the idea that the grain size distribution of basaltic eruption products reflects the density of fractures that initially fragmented the magma and ultimately indicate that brittle fracturing and viscous healing of magma may underlie basaltic explosive eruptions globally.
    Description: Published
    Description: 248–254
    Description: 4V. Processi pre-eruttivi
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
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    Neapolitan volcanoes (2021)
    Springer Nature
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    Publication Date: 2021-12-24
    Description: This book serves as a guide to discovering the most interesting volcano sites in Italy. Accompanied by some extraordinary contemporary images of active Neapolitan volcanoes, it explains the main volcanic processes that have been shaping the landscape of the Campania region and influencing human settlements in this area since Greek and Roman times and that have prompted leading international scientists to visit and study this natural volcanology laboratory. While volcanology is the central topic, the book also addresses other aspects related to the area’s volcanism and is divided into three sections: 1) Neapolitan volcanic activity and processes (with a general introduction to volcanology and its development around Naples together with descriptions of the landscape and the main sites worth visiting); 2) Volcanoes and their interactions with local human settlements since the Bronze Age, recent population growth and the transformation of the territory; 3) The risks posed by Neapolitan Volcanoes, their recent activity and the problem of forecasting any future eruption.
    Description: Published
    Description: 2TM. Divulgazione Scientifica
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    Northern Hemisphere drought risk in a warming climate (2021)
    Springer Nature
    In:  EPIC3npj Climate and Atmospheric Science, Springer Nature, 4(1), ISSN: 2397-3722
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    Publication Date: 2022-02-15
    Repository Name: EPIC Alfred Wegener Institut
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    Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals (2021)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Babbin, A. R., Tamasi, T., Dumit, D., Weber, L., Rodríguez, M. V. I., Schwartz, S. L., Armenteros, M., Wankel, S. D., & Apprill, A. Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals. ISME Journal, (2020), doi:10.1038/s41396-020-00845-2.
    Description: Coral reef health depends on an intricate relationship among the coral animal, photosynthetic algae, and a complex microbial community. The holobiont can impact the nutrient balance of their hosts amid an otherwise oligotrophic environment, including by cycling physiologically important nitrogen compounds. Here we use 15N-tracer experiments to produce the first simultaneous measurements of ammonium oxidation, nitrate reduction, and nitrous oxide (N2O) production among five iconic species of reef-building corals (Acropora palmata, Diploria labyrinthiformis, Orbicella faveolata, Porites astreoides, and Porites porites) in the highly protected Jardines de la Reina reefs of Cuba. Nitrate reduction is present in most species, but ammonium oxidation is low potentially due to photoinhibition and assimilatory competition. Coral-associated rates of N2O production indicate a widespread potential for denitrification, especially among D. labyrinthiformis, at rates of ~1 nmol cm−2 d−1. In contrast, A. palmata displays minimal active nitrogen metabolism. Enhanced rates of nitrate reduction and N2O production are observed coincident with dark net respiration periods. Genomes of bacterial cultures isolated from multiple coral species confirm that microorganisms with the ability to respire nitrate anaerobically to either dinitrogen gas or ammonium exist within the holobiont. This confirmation of anaerobic nitrogen metabolisms by coral-associated microorganisms sheds new light on coral and reef productivity.
    Description: Research was conducted in the Gardens of the Queen, Cuba in accordance with the requirements of the Republic of Cuba, conducted under permit NV2370 and NV2568 issued by the Ministerio de Relaciones Exteriores. We gratefully acknowledge funding for this research by MIT Sea Grant award #2018-DOH-49-LEV, Simons Foundation award #622065, and MIT ESI seed funding to ARB, the MIT Montrym, Ferry, and mTerra Seed Grant Funds, and the generous contributions by Dr Bruce L. Heflinger.
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    Time-series transcriptomics from cold, oxic subseafloor crustal fluids reveals a motile, mixotrophic microbial community (2021)
    Springer Nature
    Details
    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Seyler, L. M., Trembath-Reichert, E., Tully, B. J., & Huber, J. A. Time-series transcriptomics from cold, oxic subseafloor crustal fluids reveals a motile, mixotrophic microbial community. Isme Journal, (2020), doi:10.1038/s41396-020-00843-4.
    Description: The oceanic crustal aquifer is one of the largest habitable volumes on Earth, and it harbors a reservoir of microbial life that influences global-scale biogeochemical cycles. Here, we use time series metagenomic and metatranscriptomic data from a low-temperature, ridge flank environment representative of the majority of global hydrothermal fluid circulation in the ocean to reconstruct microbial metabolic potential, transcript abundance, and community dynamics. We also present metagenome-assembled genomes from recently collected fluids that are furthest removed from drilling disturbances. Our results suggest that the microbial community in the North Pond aquifer plays an important role in the oxidation of organic carbon within the crust. This community is motile and metabolically flexible, with the ability to use both autotrophic and organotrophic pathways, as well as function under low oxygen conditions by using alternative electron acceptors such as nitrate and thiosulfate. Anaerobic processes are most abundant in subseafloor horizons deepest in the aquifer, furthest from connectivity with the deep ocean, and there was little overlap in the active microbial populations between sampling horizons. This work highlights the heterogeneity of microbial life in the subseafloor aquifer and provides new insights into biogeochemical cycling in ocean crust.
    Description: The Gordon and Betty Moore Foundation sponsored most of the observatory components at North Pond through grant GBMF1609. This work was supported by NSF OCE-1062006, OCE-1745589 and OCE-1635208 to J.A.H. E.T.R. was supported by a NASA Postdoctoral Fellowship with the NASA Astrobiology Institute and a L’Oréal USA For Women in Science Fellowship. The Center for Dark Energy Biosphere Investigations (C-DEBI OCE-0939564) also supported the participation of J.A.H. and B.T. This is C-DEBI contribution number 548.
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    Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks (2021)
    Springer Nature
    Details
    Publication Date: 2022-05-27
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Coskun, O. K., Vuillemin, A., Schubotz, F., Klein, F., Sichel, S. E., Eisenreich, W., & Orsi, W. D. Quantifying the effects of hydrogen on carbon assimilation in a seafloor microbial community associated with ultramafic rocks. Isme Journal. (2021), https://doi.org/10.1038/s41396-021-01066-x.
    Description: Thermodynamic models predict that H2 is energetically favorable for seafloor microbial life, but how H2 affects anabolic processes in seafloor-associated communities is poorly understood. Here, we used quantitative 13C DNA stable isotope probing (qSIP) to quantify the effect of H2 on carbon assimilation by microbial taxa synthesizing 13C-labeled DNA that are associated with partially serpentinized peridotite rocks from the equatorial Mid-Atlantic Ridge. The rock-hosted seafloor community was an order of magnitude more diverse compared to the seawater community directly above the rocks. With added H2, peridotite-associated taxa increased assimilation of 13C-bicarbonate and 13C-acetate into 16S rRNA genes of operational taxonomic units by 146% (±29%) and 55% (±34%), respectively, which correlated with enrichment of H2-oxidizing NiFe-hydrogenases encoded in peridotite-associated metagenomes. The effect of H2 on anabolism was phylogenetically organized, with taxa affiliated with Atribacteria, Nitrospira, and Thaumarchaeota exhibiting the most significant increases in 13C-substrate assimilation in the presence of H2. In SIP incubations with added H2, an order of magnitude higher number of peridotite rock-associated taxa assimilated 13C-bicarbonate, 13C-acetate, and 13C-formate compared to taxa that were not associated with peridotites. Collectively, these findings indicate that the unique geochemical nature of the peridotite-hosted ecosystem has selected for H2-metabolizing, rock-associated taxa that can increase anabolism under high H2 concentrations. Because ultramafic rocks are widespread in slow-, and ultraslow-spreading oceanic lithosphere, continental margins, and subduction zones where H2 is formed in copious amounts, the link between H2 and carbon assimilation demonstrated here may be widespread within these geological settings.
    Description: This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project-ID 364653263—TRR 235 to WDO and WE, and under Germany’s Excellence Strategy—EXC 2077-390741603. The work was also supported by the Dalio Explore Fund and LMU Mentoring Program. Open Access funding enabled and organized by Projekt DEAL.
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    Degradation of biological macromolecules supports uncultured microbial populations in Guaymas Basin hydrothermal sediments (2021)
    Springer Nature
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    Publication Date: 2022-05-27
    Description: © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Castro, S. P., Borton, M. A., Regan, K., de Angelis, I. H., Wrighton, K. C., Teske, A. P., Strous, M., & Ruff, S. E. Degradation of biological macromolecules supports uncultured microbial populations in Guaymas Basin hydrothermal sediments. Isme Journal. (2021), https://doi.org/10.1038/s41396-021-01026-5.
    Description: Hydrothermal sediments contain large numbers of uncultured heterotrophic microbial lineages. Here, we amended Guaymas Basin sediments with proteins, polysaccharides, nucleic acids or lipids under different redox conditions and cultivated heterotrophic thermophiles with the genomic potential for macromolecule degradation. We reconstructed 20 metagenome-assembled genomes (MAGs) of uncultured lineages affiliating with known archaeal and bacterial phyla, including endospore-forming Bacilli and candidate phylum Marinisomatota. One Marinisomatota MAG had 35 different glycoside hydrolases often in multiple copies, seven extracellular CAZymes, six polysaccharide lyases, and multiple sugar transporters. This population has the potential to degrade a broad spectrum of polysaccharides including chitin, cellulose, pectin, alginate, chondroitin, and carrageenan. We also describe thermophiles affiliating with the genera Thermosyntropha, Thermovirga, and Kosmotoga with the capability to make a living on nucleic acids, lipids, or multiple macromolecule classes, respectively. Several populations seemed to lack extracellular enzyme machinery and thus likely scavenged oligo- or monomers (e.g., MAGs affiliating with Archaeoglobus) or metabolic products like hydrogen (e.g., MAGs affiliating with Thermodesulfobacterium or Desulforudaceae). The growth of methanogens or the production of methane was not observed in any condition, indicating that the tested macromolecules are not degraded into substrates for methanogenesis in hydrothermal sediments. We provide new insights into the niches, and genomes of microorganisms that actively degrade abundant necromass macromolecules under oxic, sulfate-reducing, and fermentative thermophilic conditions. These findings improve our understanding of the carbon flow across trophic levels and indicate how primary produced biomass sustains complex and productive ecosystems.
    Description: We are grateful to the captain and crew of the R/V Atlantis AT37-06 as well as the crew of the human occupied vehicle Alvin for their tireless support. Sampling at Guaymas Basin was supported by NSF (OCE-1357238).
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    Metabolic versatility of the nitrite-oxidizing bacterium Nitrospira marina and its proteomic response to oxygen-limited conditions (2021)
    Springer Nature
    Details
    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bayer, B., Saito, M. A., McIlvin, M. R., Lucker, S., Moran, D. M., Lankiewicz, T. S., Dupont, C. L., & Santoro, A. E. (2020). Metabolic versatility of the nitrite-oxidizing bacterium Nitrospira marina and its proteomic response to oxygen-limited conditions. Isme Journal, doi:10.1038/s41396-020-00828-3.
    Description: The genus Nitrospira is the most widespread group of nitrite-oxidizing bacteria and thrives in diverse natural and engineered ecosystems. Nitrospira marina Nb-295T was isolated from the ocean over 30 years ago; however, its genome has not yet been analyzed. Here, we investigated the metabolic potential of N. marina based on its complete genome sequence and performed physiological experiments to test genome-derived hypotheses. Our data confirm that N. marina benefits from additions of undefined organic carbon substrates, has adaptations to resist oxidative, osmotic, and UV light-induced stress and low dissolved pCO2, and requires exogenous vitamin B12. In addition, N. marina is able to grow chemoorganotrophically on formate, and is thus not an obligate chemolithoautotroph. We further investigated the proteomic response of N. marina to low (∼5.6 µM) O2 concentrations. The abundance of a potentially more efficient CO2-fixing pyruvate:ferredoxin oxidoreductase (POR) complex and a high-affinity cbb3-type terminal oxidase increased under O2 limitation, suggesting a role in sustaining nitrite oxidation-driven autotrophy. This putatively more O2-sensitive POR complex might be protected from oxidative damage by Cu/Zn-binding superoxide dismutase, which also increased in abundance under low O2 conditions. Furthermore, the upregulation of proteins involved in alternative energy metabolisms, including Group 3b [NiFe] hydrogenase and formate dehydrogenase, indicate a high metabolic versatility to survive conditions unfavorable for aerobic nitrite oxidation. In summary, the genome and proteome of the first marine Nitrospira isolate identifies adaptations to life in the oxic ocean and provides insights into the metabolic diversity and niche differentiation of NOB in marine environments.
    Description: We thank John B. Waterbury and Frederica Valois for providing the culture of Nitrospira marina Nb-295T and for continued advice about cultivation. The N. marina genome was sequenced as part of US Department of Energy Joint Genome Institute Community Sequencing Project 1337 to CLD, AES, and MAS in collaboration with the user community. We thank Claus Pelikan for bioinformatic assistance. This research was supported by a Simons Foundation Early Career Investigator in Marine Microbiology and Evolution Award (345889) and US National Science Foundation (NSF) award OCE-1924512 to AES. Proteomics analysis was supported by NSF awards OCE-1924554 and OCE-1850719, and NIH award R01GM135709 to MAS. BB was supported by the Austrian Science Fund (FWF) Project Number: J4426-B (“The influence of nitrifiers on the oceanic carbon cycle”), SL by the Netherlands Organization for Scientific Research (NWO) grant 016.Vidi.189.050, and CLD by NSF award OCE-125999.
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    Resource partitioning of phytoplankton metabolites that support bacterial heterotrophy (2020)
    Springer Nature
    Details
    Publication Date: 2022-05-25
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ferrer-González, F. X., Widner, B., Holderman, N. R., Glushka, J., Edison, A. S., Kujawinski, E. B., & Moran, M. A. Resource partitioning of phytoplankton metabolites that support bacterial heterotrophy. ISME Journal, (2020), doi:10.1038/s41396-020-00811-y.
    Description: The communities of bacteria that assemble around marine microphytoplankton are predictably dominated by Rhodobacterales, Flavobacteriales, and families within the Gammaproteobacteria. Yet whether this consistent ecological pattern reflects the result of resource-based niche partitioning or resource competition requires better knowledge of the metabolites linking microbial autotrophs and heterotrophs in the surface ocean. We characterized molecules targeted for uptake by three heterotrophic bacteria individually co-cultured with a marine diatom using two strategies that vetted the exometabolite pool for biological relevance by means of bacterial activity assays: expression of diagnostic genes and net drawdown of exometabolites, the latter detected with mass spectrometry and nuclear magnetic resonance using novel sample preparation approaches. Of the more than 36 organic molecules with evidence of bacterial uptake, 53% contained nitrogen (including nucleosides and amino acids), 11% were organic sulfur compounds (including dihydroxypropanesulfonate and dimethysulfoniopropionate), and 28% were components of polysaccharides (including chrysolaminarin, chitin, and alginate). Overlap in phytoplankton-derived metabolite use by bacteria in the absence of competition was low, and only guanosine, proline, and N-acetyl-d-glucosamine were predicted to be used by all three. Exometabolite uptake pattern points to a key role for ecological resource partitioning in the assembly marine bacterial communities transforming recent photosynthate.
    Description: This work was supported by grants from the Gordon and Betty Moore Foundation (5503) and the National Science Foundation (IOS-1656311) to MAM, ASE, and EBK, and by the Simons Foundation grant 542391 to MAM within the Principles of Microbial Ecosystems (PriME) Collaborative.
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    Stable aerobic and anaerobic coexistence in anoxic marine zones (2020)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Zakem, E. J., Mahadevan, A., Lauderdale, J. M., & Follows, M. J. Stable aerobic and anaerobic coexistence in anoxic marine zones. ISME Journal, 14, (2019): 288–301, doi: 10.1038/s41396-019-0523-8.
    Description: Mechanistic description of the transition from aerobic to anaerobic metabolism is necessary for diagnostic and predictive modeling of fixed nitrogen loss in anoxic marine zones (AMZs). In a metabolic model where diverse oxygen- and nitrogen-cycling microbial metabolisms are described by underlying redox chemical reactions, we predict a transition from strictly aerobic to predominantly anaerobic regimes as the outcome of ecological interactions along an oxygen gradient, obviating the need for prescribed critical oxygen concentrations. Competing aerobic and anaerobic metabolisms can coexist in anoxic conditions whether these metabolisms represent obligate or facultative populations. In the coexistence regime, relative rates of aerobic and anaerobic activity are determined by the ratio of oxygen to electron donor supply. The model simulates key characteristics of AMZs, such as the accumulation of nitrite and the sustainability of anammox at higher oxygen concentrations than denitrification, and articulates how microbial biomass concentrations relate to associated water column transformation rates as a function of redox stoichiometry and energetics. Incorporating the metabolic model into an idealized two-dimensional ocean circulation results in a simulated AMZ, in which a secondary chlorophyll maximum emerges from oxygen-limited grazing, and where vertical mixing and dispersal in the oxycline also contribute to metabolic co-occurrence. The modeling approach is mechanistic yet computationally economical and suitable for global change applications.
    Description: We are grateful for the thorough and thoughtful comments of two anonymous reviewers. We also thank Andrew Babbin for helpful comments. EJZ was supported by the Simons Foundation (Postdoctoral Fellowship in Marine Microbial Ecology). AM was supported by the Office of Naval Research (ONR #N000-14-15-1-2555). JML was supported by U.S. National Science Foundation (NSF #OCE-1259388). MJF was supported by the Gordon and Betty Moore Foundation (GBMF #3778) and the Simons Foundation: the Simons Collaboration on Ocean Processes and Ecology (SCOPE #329108) and the Simons Collaboration on Computational Biogeochemical Modeling of Marine Ecosystems (CBIOMES #549931).
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    Comparative proteomics of related symbiotic mussel species reveals high variability of host-symbiont interactions (2020)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ponnudurai, R., Heiden, S. E., Sayavedra, L., Hinzke, T., Kleiner, M., Hentschker, C., Felbeck, H., Sievert, S. M., Schlüter, R., Becher, D., Schweder, T., & Markert, S. Comparative proteomics of related symbiotic mussel species reveals high variability of host-symbiont interactions. ISME Journal, 14, (2019): 649–656, doi: 10.1038/s41396-019-0517-6.
    Description: Deep-sea Bathymodiolus mussels and their chemoautotrophic symbionts are well-studied representatives of mutualistic host–microbe associations. However, how host–symbiont interactions vary on the molecular level between related host and symbiont species remains unclear. Therefore, we compared the host and symbiont metaproteomes of Pacific B. thermophilus, hosting a thiotrophic symbiont, and Atlantic B. azoricus, containing two symbionts, a thiotroph and a methanotroph. We identified common strategies of metabolic support between hosts and symbionts, such as the oxidation of sulfide by the host, which provides a thiosulfate reservoir for the thiotrophic symbionts, and a cycling mechanism that could supply the host with symbiont-derived amino acids. However, expression levels of these processes differed substantially between both symbioses. Backed up by genomic comparisons, our results furthermore revealed an exceptionally large repertoire of attachment-related proteins in the B. thermophilus symbiont. These findings imply that host–microbe interactions can be quite variable, even between closely related systems.
    Description: Thanks to captain, crew, and pilots of the research vessels Atlantis (ROV Jason cruise AT26–10 in 2014) and Meteor (cruise M82–3 in 2010). We thank Jana Matulla, Sebastian Grund, and Annette Meuche for excellent technical assistance during sample preparation, MS measurements in the Orbitrap Classic, and TEM imaging preparation, respectively. We appreciate Nikolaus Leisch’s help with TEM image interpretation, Inna Sokolova’s advice on bivalve physiology, and Marie Zühlke’s support during manuscript revision. RP was supported by the EU-funded Marie Curie Initial Training Network ‘Symbiomics’ (project no. 264774) and by a fellowship of the Institute of Marine Biotechnology e.V. TH was supported by the German Research Foundation DFG (grant MA 6346/2–1 to SM). The Atlantis cruise was funded by a grant of the US National Science Foundation’s Dimensions of Biodiversity program to SMS (OCE-1136727).
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    Coordinated transformation of the gut microbiome and lipidome of bowhead whales provides novel insights into digestion (2020)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Miller, C. A., Holm, H. C., Horstmann, L., George, J. C., Fredricks, H. F., Van Mooy, B. A. S., & Apprill, A. Coordinated transformation of the gut microbiome and lipidome of bowhead whales provides novel insights into digestion. ISME Journal, 14, (2019): 688-701, doi: 10.1038/s41396-019-0549-y.
    Description: Whale digestion plays an integral role in many ocean ecosystems. By digesting enormous quantities of lipid-rich prey, whales support their energy intensive lifestyle, but also excrete nutrients important to ocean biogeochemical cycles. Nevertheless, whale digestion is poorly understood. Gastrointestinal microorganisms play a significant role in vertebrate digestion, but few studies have examined them in whales. To investigate digestion of lipids, and the potential contribution of microbes to lipid digestion in whales, we characterized lipid composition (lipidomes) and bacterial communities (microbiotas) in 126 digesta samples collected throughout the gastrointestinal tracts of 38 bowhead whales (Balaena mysticetus) harvested by Alaskan Eskimos. Lipidomes and microbiotas were strongly correlated throughout the gastrointestinal tract. Lipidomes and microbiotas were most variable in the small intestine and most similar in the large intestine, where microbiota richness was greatest. Our results suggest digestion of wax esters, the primary lipids in B. mysticetus prey representing more than 80% of total dietary lipids, occurred in the mid- to distal small intestine and was correlated with specific microorganisms. Because wax esters are difficult to digest by other marine vertebrates and constitute a large reservoir of carbon in the ocean, our results further elucidate the essential roles that whales and their gastrointestinal microbiotas play in the biogeochemical cycling of carbon and nutrients in high-latitude seas.
    Description: Devonshire Foundation (to CAM), Marine Mammal Center, Woods Hole Oceanographic Institution (WHOI; to CAM), WHOI Ocean Life Institute (to AA and CAM), Dalio Foundation’s Dalio Ocean Initiative (now ‘OceanX’) (to AA), National Science Foundation (OCE-1756254 and OPP-1543328 to BASVM). Samples were collected under Department of Commerce National Oceanic and Atmospheric Administration National Marine Fisheries Service permit numbers 17350-00, 17350-01, and 17350-02 to North Slope Borough Department of Wildlife Management.
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    Potential virus-mediated nitrogen cycling in oxygen-depleted oceanic waters (2020)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Gazitua, M. C., Vik, D. R., Roux, S., Gregory, A. C., Bolduc, B., Widner, B., Mulholland, M. R., Hallam, S. J., Ulloa, O., & Sullivan, M. B. Potential virus-mediated nitrogen cycling in oxygen-depleted oceanic waters. Isme Journal, (2020), doi:10.1038/s41396-020-00825-6.
    Description: Viruses play an important role in the ecology and biogeochemistry of marine ecosystems. Beyond mortality and gene transfer, viruses can reprogram microbial metabolism during infection by expressing auxiliary metabolic genes (AMGs) involved in photosynthesis, central carbon metabolism, and nutrient cycling. While previous studies have focused on AMG diversity in the sunlit and dark ocean, less is known about the role of viruses in shaping metabolic networks along redox gradients associated with marine oxygen minimum zones (OMZs). Here, we analyzed relatively quantitative viral metagenomic datasets that profiled the oxygen gradient across Eastern Tropical South Pacific (ETSP) OMZ waters, assessing whether OMZ viruses might impact nitrogen (N) cycling via AMGs. Identified viral genomes encoded six N-cycle AMGs associated with denitrification, nitrification, assimilatory nitrate reduction, and nitrite transport. The majority of these AMGs (80%) were identified in T4-like Myoviridae phages, predicted to infect Cyanobacteria and Proteobacteria, or in unclassified archaeal viruses predicted to infect Thaumarchaeota. Four AMGs were exclusive to anoxic waters and had distributions that paralleled homologous microbial genes. Together, these findings suggest viruses modulate N-cycling processes within the ETSP OMZ and may contribute to nitrogen loss throughout the global oceans thus providing a baseline for their inclusion in the ecosystem and geochemical models.
    Description: We thank Sullivan Lab members and Heather Maughan for comments on the paper, Bess Ward for her contribution in the N-cycle context of our story, Kurt Hanselmann for his assistance in the calculations of the Gibbs-free energies, and the scientific party and crew of the R/V Atlantis (grant OCE-1356056 to MRM) for the sampling opportunity and support at sea. This work was funded in part by awards from the Agouron Institute to OU and MBS, a Gordon and Betty Moore Foundation Investigator Award (#3790) and NSF Biological Oceanography Awards (#1536989 and #1829831) to MBS, and the Millennium Science Initiative (grant ICN12_019-IMO) to OU. The work conducted by the U.S. Department of Energy Joint Genome Institute is supported by the Office of Science of the U.S. Department of Energy under contract no. DE-AC02-05CH11231.
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    Physiological dynamics of chemosynthetic symbionts in hydrothermal vent snails (2020)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Breusing, C., Mitchell, J., Delaney, J., Sylva, S. P., Seewald, J. S., Girguis, P. R., & Beinart, R. A. Physiological dynamics of chemosynthetic symbionts in hydrothermal vent snails. Isme Journal, (2020), doi:10.1038/s41396-020-0707-2.
    Description: Symbioses between invertebrate animals and chemosynthetic bacteria form the basis of hydrothermal vent ecosystems worldwide. In the Lau Basin, deep-sea vent snails of the genus Alviniconcha associate with either Gammaproteobacteria (A. kojimai, A. strummeri) or Campylobacteria (A. boucheti) that use sulfide and/or hydrogen as energy sources. While the A. boucheti host–symbiont combination (holobiont) dominates at vents with higher concentrations of sulfide and hydrogen, the A. kojimai and A. strummeri holobionts are more abundant at sites with lower concentrations of these reductants. We posit that adaptive differences in symbiont physiology and gene regulation might influence the observed niche partitioning between host taxa. To test this hypothesis, we used high-pressure respirometers to measure symbiont metabolic rates and examine changes in gene expression among holobionts exposed to in situ concentrations of hydrogen (H2: ~25 µM) or hydrogen sulfide (H2S: ~120 µM). The campylobacterial symbiont exhibited the lowest rate of H2S oxidation but the highest rate of H2 oxidation, with fewer transcriptional changes and less carbon fixation relative to the gammaproteobacterial symbionts under each experimental condition. These data reveal potential physiological adaptations among symbiont types, which may account for the observed net differences in metabolic activity and contribute to the observed niche segregation among holobionts.
    Description: We thank the Schmidt Ocean Institute, the crew of the R/V Falkor and the pilots of the ROV ROPOS for facilitating the sample collections and shipboard experiments, and the Broad Institute Microbial ‘Omics Core for preparing and sequencing the transcriptomic libraries. This material is based in part upon work supported by the National Science Foundation under Grant Numbers NSF OCE-1536653 (to PRG), OCE-1536331 (to RAB and JSS), OCE-1819530 and OCE-1736932 (to RAB).
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    Viral elements and their potential influence on microbial processes along the permanently stratified Cariaco Basin redoxcline (2020)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Mara, P., Vik, D., Pachiadaki, M. G., Suter, E. A., Poulos, B., Taylor, G. T., Sullivan, M. B., & Edgcomb, V. P. Viral elements and their potential influence on microbial processes along the permanently stratified Cariaco Basin redoxcline. ISME Journal, (2020), doi:10.1038/s41396-020-00739-3.
    Description: Little is known about viruses in oxygen-deficient water columns (ODWCs). In surface ocean waters, viruses are known to act as gene vectors among susceptible hosts. Some of these genes may have metabolic functions and are thus termed auxiliary metabolic genes (AMGs). AMGs introduced to new hosts by viruses can enhance viral replication and/or potentially affect biogeochemical cycles by modulating key microbial pathways. Here we identify 748 viral populations that cluster into 94 genera along a vertical geochemical gradient in the Cariaco Basin, a permanently stratified and euxinic ocean basin. The viral communities in this ODWC appear to be relatively novel as 80 of these viral genera contained no reference viral sequences, likely due to the isolation and unique features of this system. We identify viral elements that encode AMGs implicated in distinctive processes, such as sulfur cycling, acetate fermentation, signal transduction, [Fe–S] formation, and N-glycosylation. These AMG-encoding viruses include two putative Mu-like viruses, and viral-like regions that may constitute degraded prophages that have been modified by transposable elements. Our results provide an insight into the ecological and biogeochemical impact of viruses oxygen-depleted and euxinic habitats.
    Description: This work was supported by the National Science Foundation grant OCE-1336082 to VPE, OCE-1335436 to GTT, OCE-1536989, a Moore Foundation Award (#3790) to MBS, and WHOI subaward A101259 to MP. The sequencing conducted by the U.S. Department of Energy Joint Genome Institute is supported by the Office of Science of the U.S. Department of Energy under contract no. DE-AC02-05CH11231.
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    Sediment dynamics of a divergent bay-marsh complex (2020)
    Springer Nature
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    Publication Date: 2022-05-26
    Description: Author Posting. © Springer Nature , 2020. This article is posted here by permission of Springer Nature for personal use, not for redistribution. The definitive version was published in Nowacki, D. J., & Ganju, N. K. Sediment dynamics of a divergent bay-marsh complex. Estuaries and Coasts, (2020), doi:10.1007/s12237-020-00855-5.
    Description: Bay–marsh systems, composed of an embayment surrounded by fringing marsh incised by tidal channels, are widely distributed coastal environments. External sediment availability, marsh-edge erosion, and sea-level rise acting on such bay–marsh complexes may drive diverse sediment-flux regimes. These factors reinforce the ephemeral and dynamic nature of fringing marshes: material released by marsh-edge erosion becomes part of a bay–marsh exchange that fuels the geomorphic evolution of the coupled system. The dynamics of this sediment exchange determine the balance among seaward export, deposition on the embayment seabed, flux into tidal channels, and import to the marsh platform. In this work, we investigate the sediment dynamics of a transgressive bay–marsh complex and link them to larger-scale considerations of its geomorphic trajectory. Grand Bay, Alabama/Mississippi, is a shallow microtidal embayment surrounded by salt marshes with lateral erosion rates of up to 5 m year−1. We collected 6 months of oceanographic data at four moorings within Grand Bay and its tidal channels to assess hydrographic conditions and net sediment-flux patterns and augmented the observations with numerical modeling. The observations imply a divergent sedimentary system in which a majority of the suspended sediment is exported seaward, while a smaller fraction is imported landward via tidal channels, assisting in vertical marsh-plain accumulation, maintenance of channel and intertidal-flat morphologies, and landward transgression. These results describe a dynamic system that is responsive to episodic atmospheric forcing in the absence of a strong tidal signal and the presence of severe lateral marsh loss.
    Description: We thank the staff of the Grand Bay NERR for their role in facilitating fieldwork within Grand Bay. Jonathan Pitchford, also of the Grand Bay NERR, provided the SET data. Giulio Mariotti and an anonymous reviewer are acknowledged for their helpful comments.
    Keywords: Salt marsh ; Geomorphic trajectory ; Sediment flux
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  • 37
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    Influence of thermal denaturation on the electrophoretic mobility of calf thymus DNA (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 1-8 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The results of electrophoresis experiments on aqueous solutions of native and thermally denatured DNA are reported. A significant decrease of the electrophoretic mobility has been observed following thermal denaturation, which under suitable conditions gives rise to a resolution into two peaks of 1 : 1 mixtures in the electrophoretic pattern. This result is entirely consistent with the previously reported increase of the activity coefficient of sodium counterions following thermal denaturation. The hypothesis that thermal denaturation of calf thymus DNA induces a large decrease of charge density on the macroion which has been ascribed to the population of more extended conformations of the chains in the disordered region of the molecule is therefore further confirmed.
    Additional Material: 4 Ill.
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    Studies on dextran and dextran derivatives. II. Acid hydrolysis of native dextranSupported by a grant (FG.IT-113) from the U.S. Department of Agriculture. (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 35-42 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the depolymerization of native dextran in dilute hydrochloric acid at different temperatures has been followed by measurements of M̄w, M̄n, [η], 〈ρ2〉1/2, and S. The data allow the correlation of the various parameters of the total hydrolyzate at various degrees of depolymerization. At a first approximation the results conform to a random splitting of a statistical, branched polymer.
    Additional Material: 5 Ill.
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  • 39
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    Polymerization of γ-ethyl-L-glutamate-N-carboxyanhydride initiated by di-n-butyl and di-isopropyl amine (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 69-78 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The γ-ethyl-L-glutamate NCA polymerization initiated by di-n-butyl and di-isopropyl amine was studied. The experimental kinetic curves show an autocatalytic portion with 25-30% conversion, followed by a pseudo first-order region which extends up to at least 85-90%. In this linear region, the reaction order appears to be 0.5 in initiator with both amines. High degrees of polymerization and high reaction rates were observed. These results are similar to those obtained in the γ-benzyl-L-glutamate NCA polymerization initiated by sodium methoxide.
    Additional Material: 5 Ill.
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  • 40
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    Electrooptical and dielectric investigations on the conformation and the electrical properties of poly-γ-benzyl-L-glutamate in mixed solvents (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 91-101 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The dielectric constant and the electric birefringence of poly-γ-benzyl-L-glutamate in ethylene dichloride-dichloroacetic acid mixtures have been measured as functions of the solvent composition. These properties undergo a marked decrease with the addition of a small amount of dichloroacetic acid, as well as an abrupt change accompanying the helix-coil transition in the vicinity of 75 vol.-% dichloroacetic acid. The former is attributed to the apparent diminution of the dipole moment of helical poly-γ-benzyl-L-glutamate molecule, which may be due to the protonation of terminal amide groups.
    Additional Material: 7 Ill.
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  • 41
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    Masthead (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1964.360020201
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  • 42
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    Polymerization of α-amino acid N-carboxy anhydrides in N,N-dimethylformamideThis work was supported in part by the public Health Service Research Grant GM-08409. (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 131-134 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of γ-benzyl-L-glutamate NCA initiated by n-hexylamine in DMF proceeds with two successive propagation rates whose ratio is about 1.5. The onset of the increase in rate of propagation occurred at a DPn of 7-14, which was independent of initiator to anhydride ratio and anhydride concentration and not a result of anhydride impurities. The increase in rate is likely a result of a conformational change in the polymer at a DPn of 7-14.
    Additional Material: 1 Ill.
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  • 43
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    Synthesis and polymerization of N-carboxyanhydrides of N-benzyl-β-amino acids (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 147-161 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The NCAs of the N-benzyl derivatives of β-alanine, β-DL-aminobutyric acid, and β-DL-aminoisobutyric acid (nonplanar six-membered rings) were prepared by reacting the corresponding N-chloroformyl derivatives, obtained on reaction of the N-benzyl amino acids with phosgene, with triethylamine. Contrary to the others, the NCA of N-benzyl-β-alanine polymerized readily on heating in vacuo or in solution, using n-hexylamine or methanolic sodium methoxide as initiators. With n-hexylamine the molecular weights of the polymers obtained in benzene, dioxan, and dimethylsulfoxide, were in accordance with DP = [NCA]/[Initiator], as was found with conventional five-membered ring NCAs of α-amino acids. With sodium methoxide initiation, DPs of the polymers obtained were smaller than the (NCA)/[Initiator] ratio, contrary to what was found previously with α-amino acid NCAs. The possibility that stereochemical factors are responsible for the differences in polymerization activity of various. N-alkyl β as well as α amino acid NCAs is discussed.
    Additional Material: 4 Ill.
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    Fluorescence studies on poly-α-amino acids. II. Conformation-dependent excimer emission band in poly-L-tyrosine and poly-L-tryptophanThis investigation was supported in part by research grants from the National Institute of Arthritis and Metabolic Disease (AM-05852) and from the National Science Foundation (GB-428). It is publication No. 291 from the Graduate Department of Biochemistry, Brandeis University.For the previous paper in this series, see Fasman, G.D., K. Norland, and A. Pesce, Biopolymers Symposia, 1, 325 (1964). (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 199-203 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1964.360020211
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    Electrophoresis of DNA. III. The effect of several univalent electrolytes on the mobility of DNA (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 231-236 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electrophoretic mobility of DNA in the presence of tetramethylammonium and alkali metal ion chlorides has been studied as a function of ionic strength. Each cation exhibits a characteristic behavior in accord with the idea that the order of inter-action with DNA is Li+ 〉 Na+ 〉 K+ 〉 TMA+. The application of theories of the electrophoresis of polyelectrolytes is discussed, leading to an attempt to calculate the fractional charge per DNA phosphorus from the mobility data. Over the range 0.05-0.4M a constant and unique value of the DNA charge is obtained in the presence of each cation. Values of the zeta potential and of the friction factor per monomer unit are also calculated.
    Additional Material: 1 Ill.
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  • 46
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    Theory of inactivation and reactivation of transforming DNA (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 135-146 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple quantitative theory of inactivation of transforming DNA has been formulated. It is based on the idea that genetic recombination of the molecule of transforming DNA with the bacterial genome is possible only, from the point mutation of the gene up to the nearest hit or point of damage on the corresponding DNA molecule. Our data and the data of other authors on the kinetics of inactivation by HNO2 or U.V. light or both are consistent with these theoretical predictions. Theoretical predictions were made concerning the extent of reactivation by fusion mid annealing of damaged DNA with a diluting genetically inactive DNA. These estimates have been reasonably confirmed by our experimental results.
    Additional Material: 7 Ill.
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  • 47
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    Effect of glucosylation on sedimentation velocity of DNA from T2 and T6 coliphages (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 15-25 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In order to study the effect of glucose substitution on the sedimentation velocities of the T-even phage DNA's, T2 and T2*, and T6 and T6* bacteriophages were grown with H3and P32 labeling. Zone sedimentation of the DNA's isolated from these phagea showed that the glucosylated DNA's from both T2 and T6 sediment faster than the nonglucosylated molecules. Nonglucosylated DNA from TG and T2 phages sedimented with the same velocity, suggesting that the molecules of these phages are of the same length.
    Additional Material: 6 Ill.
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  • 48
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    Partial specific volumes of synthetic polypeptides in dilute solution (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 43-49 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: We report a simple method for measuring partial specific volumes, of polymers in dilute solutions with an accuracy of 3 parts per thousand. This method has been applied to 7 polypeptides in 4 organic solvents. The residue volumes deduced from these data are compared to those calculated by a differential method. The discrepancy is generally of the order of 1.5%.
    Additional Material: 3 Tab.
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  • 49
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    Proposed nomenclature for synthetic polypeptides (polyamino acids) (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 283-286 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1964.360020310
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  • 50
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    Masthead (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1964.360020401
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    The conversion of two-stranded poly (A + U) to, three-strand poly (A + 2U) and poly A by heatA Preliminary report of this work was presented before the Biophysical Society at its Eighth Annual Meeting, Chicago, Illinois, February, 1964. (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 293-314 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is shown that the formation of the three-strand poly (A + 2U) complex is accompanied by a decrease in optical absorbance at 280 mμ, while the format ion of poly (A + U) is not. This difference makes it possible to demonstrate that in dilute solutions (∼10-4 monomolar), a 1 : 1 mixture of poly A and poly U always forms poly (A + U) at room temperature. At higher temperatures in solutions containing more than about 0.2M sodium ion, poly (A + U) is converted to poly (A + 2U) and free poly A. These results are consistent with the observations reported by Miles and Frazier, using infrared absorption spectra, at much higher polymer concentrations. It is concluded that most of the physicochemical studies of 1 : 1 mixtures of poly A and poly U in dilute aqueous solution refer to the two-stranded species.A simple thermodynamic analysis is developed to explain the two- to three-strand conversion, and with the use of a “phase diagram” showing conditions of stability of the various poly A-poly U structures as a function of salt and temperature, it is possible to estimate the value of the enthalpy of formation of poly (A + 2U).
    Additional Material: 8 Ill.
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    The adsorption of polyribonucleotides (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 337-347 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Using a chromatographic technique, the adsorption of the polyribonucleotides s-RNA and poly-A provided with tri-n-butylammonium ions from an aqueous solution on to the surface of polymeric hydrocarbon granules has been demonstrated. The aqueous solution from which adsorption takes place is the aqueous phase which results on agitating together n-butanol (100), water (130), tri-n-butylamine (10), n-butyl ether (10), and glacial acetic acid (2.5) (parts by volume). Microporous polyethylene granules, microporous fluorinated polyethylene granules, and solid grains of polyethylene powder have been employed as adsorbents. The adsorbed polyribonucleotides could be eluted by aqueous solutions of sodium chloride, urea, or triethylammonium acetate. s-RXA with tri-n-butylammonium counterions could also be adsorbed on polymethacrylic acid in tri-n-butylammonium form and eluted therefrom with aqueous urea solutions. It is considered that the adsorption from aqueous solution of polyribonucleotides with tri-n-butylammonium counterions on polymeric hydrocarbon surfaces is mediated by hydrophobic bond formation. Van der Waals forces may also contribute to the bonding. It is suggested that studies on the adsorption of polynucleotides provided with counterions: possessing nonpolar groups at an aqueous solution-polymeric hydrocarbon interlace may permit the elaboration of experimental systems to serve as models for the evaluation of the role of hydrophobic and van der Waals bonding forces in the interaction of polynucleotides with cell membrane surfaces.
    Additional Material: 5 Ill.
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    Intramoleculary crosslinked synthetic polypeptides (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 395-398 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/bip.1964.360020409
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  • 54
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    Chain regularity and flow dichroism of deoxyribonucleic acids in solution (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 361-380 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Deoxyribonucleic acids (DNA's) extracted from several biological sources have been studied by means of the flow dichroism method, using the transparent coaxial cylinder apparatus. This study has two purposes: (1) to make clear the hydrodynamic behavior of the DNA chain, and the regularity in the orientation of purine and phrimidine bases about the molecular axis; and (2) to develop this particular flow dichroism method as an established device for the study of chain regularity of DNA and other chain polymers. The velocity gradient dependence of dichroism agrees well, to a first approximation, with the behavior of a model of a hydrodynamically equivalent ellipsoid in revolution. Differences between theoretical and empirical curves have been tentatively ascribed to the flexibility of the chain under consideration. Two kinds of data, 1 lie rotary diffusion coefficient and internal dichroism, have been evaluated by a graphical device in which the double logarithmic plots of reduced dichroism and velocity gradient of flow are compared with the theoretical curve. The data obtained have shown good reproducibility for DNA samples prepared by the same method from the same biological source. However, a remarkable difference in internal dichroism and rotary diffusion constant has been observed between DNA groups of different biological origin. The difference may be caused by fragmentation of DNA during the deproteinization procedure, bill the possibility that some of these differences originate in the biological source of the DNA cannot be denied. Orientation of purine and phrimidine bases in aqueous solution is found to be quite regular in direction, as predicted by the Watson-Crick model. Dichroic spectra have shown that the direction of the oscillator dipole corresponding to the 260 mμ absorption band has a different angular relationship to the helical axis than the oscillator dipole for the 220 mμ band.
    Additional Material: 11 Ill.
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    Electron microscopic observations on the super helical structure of synthetic polypeptide (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 381-393 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A study of the super helical structure of synthetic polypeptides, such as poly-γ-benzyl-D (or L)-glutamate (PBDG or PBLG) was carried out. The PEG was dissolved in dimethylformamide (DMF). The solution was either allowed to remain at room temperature for a long time or poured into some fatty acid, such as formic acid, acetic acid, propionic acid, or caprylic acid. Whether the polymer precipitated slowly or rapidly depended upon the aging of the solution or the nature of the acid used. The precipitated gels revealed the coiled coil fibrils, but the feature and degree of coiling varied, depending upon the length of aging or the nature of the acid used for precipitation. After a short aging of the solution, there was no helical structure in the gels. After long aging, very fine-coiled coil macrofibrils or small spindle-like fibrils were obtained. The macrofibrils consisted of the spindle-like fibrils which in turn consisted of microfibrils (diam. 60-70A.). When using the fatty acid precipitation very fine to medium fine super helices were obtained. Extremely fine super helices were obtained in propionic acid. In these gels the PBG chains have an α-helical conformation. When PMLG-DCA solution was stored for a long time, another type of precipitation was obtained, one giving evidence of so-called cross-β crystallization and no coiled coil fibrils. The precipitation of cross-β fibrils was obtained when the concentration of the solution was above 8%.
    Additional Material: 12 Ill.
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  • 56
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    Masthead (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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    URL: http://dx.doi.org/10.1002/bip.1964.360020501
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  • 57
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    A polynucleotide helix containing polinosinic acid and protoated polycytidylic acid (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 399-413 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Titration studies of the 1 : 1 helical polynucleotide complex of polyinosinic acid and polycytidylic acid reveal that these two polymers form a complex when the polycytidylic acid is protonated near pH 3. Sedimentation studies show that the protonated complex also has a 1 : 1 stoichiometry. However, the protonated complex is more stable than the unprotonated neutral complex as judged by its thermal stability. The molecular structure of the protonated complex is not the same as the neutral form. Study of the kinetics of the reaction of the protonated complex with formaldehyde suggests that the amino group of cytosine is involved in hydrogen bonds which hold the polynucleotide strands together.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1964.360020502
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    Reconstruction of protein and nucleic acid sequences. I. Systematics and computer program (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 415-444 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The protein sequences now known have been reconstructed as a kind of intriguing logical-mathematical puzzle using information about fragments of the molecules. We wish to show that the reconstruction can be done systematically by repeating a series of elementary operations on these same data governed by a set of well-defined rules. The completely automatic reconstruction of polymer sequences by a high speed digital computer using these operations and rules is demonstrated.
    Additional Material: 1 Ill.
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  • 59
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    The renaturation of deoxyribonucleic acids. I. Rates of bimolecular reactions of complementary and noncomplementary Gaussian chains (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 445-462 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The mechanism of the renaturation of DNA molecules is examined on the basis of the bimolecular interaction of Gaussian chain polymers. In the nucleus formation by hydrogen bonding in segment-segment interaction, two types of interchain interaction, that is, one between complementary chains and one between noncomplementary chains, and one noncomplementary intrachain interaction are considered to be, in competition. Several previously observed characteristics of the renaturation process are displayed by this simple model. In particular it accounts for the dependence of the extent of renaturation on the heterogeneity, molecular weight, and radius of gyration of DNA, and of the ratios of the reaction rates between complementary and noncomplementary segments. Among these variables the ratio of reaction rates has shown to have a quite specific value, as high as the order of 104, which favors the complementary-strand interaction. This very great bias in favor of complementary strand interaction emphasizes that the renaturation phenomena displays the same character of biological specificity that is associated with enzyme-substrate interaction or antigen-antibody interaction. Moreover, since DNA is a good example of a one-dimensional system, it seems to provide a suitable clue for pursuing the analysis of pattern recognition at the macromolecular level.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1964.360020504
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    Polymerization of DL-β-phenylalanine N-carboxy anhydride adsorbed on polysarcosine dimethylamide (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 463-481 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The polymerization of DL-β-Phenylalanine N-carboxy anhydride adsorbed on polysarcosine dimethylamide has been studied further. This unusual reaction, which is analogous kinetically to reactions catalyzed by enzymes, was called the “chain-effect.” For polymerization of N-carboxy anhydrides by this mechanism it is necessary that the initiating polymer should possess an adsorption site and a terminal base group. The effect is shown to occur with simple compounds such as amino acid dimethylamides but not with poly-L-proline due to the inability of this polymer to adsorb the anhydride. From a study of the reaction of block copolymers of L-proline and sarcosine with DL-β-phenylalanine it is concluded that the relative positions of the adsorption site and terminal base group do not greatly influence the reaction rate, but the accessibility of the adsorption sites is an important factor determining the reactivity of polysarcosine dimethylamides of various degrees of polymerization (n). At high values of n the polymer exists in a coiled form and only those sites close to the terminal base group participate in the reaction. Initial rate studies give a detailed description of the early stage of the chain-effect polymerization. With these data and by use of analog computer techniques the complete reaction has been studied. It is concluded that the poly-DL-β-phenylalanine block produced is not permanently attached to the polysarcosine chain by hydrogen bonds during its formation but that an equilibrium exists between the polysarcosine and the poly-DL-phenylalanine blocks.
    Additional Material: 6 Ill.
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    The role of the σ-framework in the properties of the biological purines and pyrimidines: dipole moments and tautomeric equilibria (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 483-488 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Del Re's method for the study of saturated compounds has been adapted so as to deal with the σ-framework of conjugated molecules. This modified procedure is used in evaluating the σ-contribution to the dipole moments of the nucleic bases and of the A-T and G-C base pairs and also to the free energy change in the tautomeric, equilibria of the bases. Associated with an appropriate Hückel method for evaluating the π-contribution, the results obtained predict a small resultant moment for A-T versus a large moment for G-C. The energy calculations predict the keto and amino forms of the bases to be the most stable forms and cytosine to be the most easily involved in tautomeric shift to the rare form.
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    Masthead (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.360020601
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    The dynamics of the helix-coil transition in poly-α, L-glutamic acidAn account of this work formed part of a paper delivered at the Fifth International Congress of Biochemistry, Moscow, 1961. (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 489-500 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Temperature jump measurements employing optical rotation to follow transients show an upper limit of 10μsec. on the half time of the helix-random coil relaxation in poly-α, L-glutamic acid. No relaxations are observed under conditions where the polymer exists in completely helical or completely random coil form. Assuming that the helix-coil transition can be described kinetically as a pure growth process, expressions for the relaxation time are derived for three special cases. A comparison is made between the rate of the helix-coil transition and the rate of imide proton exchange.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/bip.1964.360020507
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    Proposed nomeneclature for synthetic polypeptides (polyamino acids) (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 501-501 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1964.360020508
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    Energy levels of almost-periodic polymers (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 561-574 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Numerical calculations have been done on the exciton spectrum of a schematic model of a linear polymer. The model consists of a random sequence of two kinds of subunit whose energy levels and transition moments are almost, but not quite, the same. The orders of magnitude of parameters are taken from DNA, but the full helical geometry has not been considered. Results are given for the density of energy levels, the dipole transition strength per unit energy, and the distribution of excitation energy along the polymer in individual states. A number of localized exciton states were found.
    Additional Material: 6 Ill.
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  • 66
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    Masthead (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964) 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1964.360020101
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    Electrophoresis of DNA. I. On a relationship between electrophoresis and donnan equilibrium experiments on DNA (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 9-14 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A calculation based upon Gorin's equation for the electrophoresis of a rigid cylinder is used to compare the available results of electrophoresis and membrane equilibrium experiments on DNA. The distribution of chloride ions across a membrane impermeable to DXA is considered. For a reasonable choice of parameters, agreement within about 2% is obtained between the values calculated from electrophoresis and the results of membrane equilibrium studies over a twenty-fold range of NaCl concentration.
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    Studies on dextran and dextran derivatives. I. Properties of native dextran in different solventsSupported by a grant (FG.IT-113) from the U. S. Department of Agriculture. (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 27-34 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Light-scattering, sedimentation, viscosity, and reducing power measurements have been carried out on a sample of native dextran from Leuconostoc mesenteriodes B-512. The results are discussed in relation to the structure, polydispersity, and branching of the polysaccharide. The effect of different solvents on the behavior of native dextran has been studied. The molecular weight of the dextran remains unchanged in all the solvents used, while the radius of gyration shows a significant increase in some of them (concentrated salts, urea, and glucose solutions); in water-methanol solutions the radius of gyration slightly decreases.
    Additional Material: 3 Ill.
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    On the theory of order-disorder transition and copolymer structure of DNA (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 65-68 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The statistical mechanical theory of the helix-coil transition of DNA has been recently discussed by one of the authors, who considered an assembly of DNA molecules with a Markoff distribution of nucleotide sequences. The present communication improves upon the above mentioned theory by introducing approximate normalization factors for the unnormalized statistical weights of finding a given molecule of the assembly in a given microscopic state.
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    Biopolymer news (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 103-103 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1964.360020113
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    Electrophoresis of DNA. II. Specific interactions of univalent and divalent cations with DNA (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 79-89 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of small quantities of metal ions on the electrophoretic mobility of calf thymus DNA in solutions maintained at 0.2 ionic strength with weakly interacting (CH3)4N+ ions yields information about interactions occurring in a region very close to the polymer chain. By means of this technique, it is demonstrated that the binding order to DNA is Li+ 〉 Na+ 〉 K+ for the alkali metal ions and Mn++ 〉 Mg ++ 〉 Ca++ for the divalent ions studied. The quantitative details are compared to earlier work on the long-chain polyphosphates. Close agreement between the two systems is obtained indicating that an intrinsic property of individual phosphate groups is being observed and that minor discrepancies probably arise from secondary factors. Three types of stability constants representing the binding of alkali metal ions to DNA are calculated and although differing in absolute magnitude, they all satisfactorily represent the result that the order of interaction is Li+ 〉 Na+ 〉 K+ with respective relative strengths of 1.5 : 1 : 0.8.
    Additional Material: 2 Ill.
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    The method for estimation of chain macromolecule rigidity (1964)
    New York : Wiley-Blackwell
    Biopolymers 2 (1964), S. 113-121 
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    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Birefringence relaxation times on removing the electric field characterize the rigidity of a flexible linear macromolecule structure. Electrical birefringence investigation of DNA solutions supports this view. This principal regularities displayed by relaxation times of electric birefringence decay curves in solutions of chain macromolecules are considered.
    Additional Material: 6 Ill.
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    Umsetzung von Nitroaromaten mit Grignard-Verbindungen, III (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 186-189 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: m-Dinitro-benzol und einige seiner Derivate (I, II, VII) lassen sich durch aufein-anderfolgende Einwirkung von Alkylmagnesiumhalogeniden, Methylamin/Formaldehyd und Essigsäure zu Mannich-Verbindungen von Dinitrodialkylcyclohexenen (Vb-e, VIII) umsetzen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970126
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    Die Reaktion cyclischer Allylbromide mit Lithiumaluminiumhydrid (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 132-139 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Brom-cyclo-penten,-hexen und-hepten reagieren mit Lithiumaluminiumhydrid unter Bildung der jeweiligen cyclischen Monoolefine. Ann substituierten 3-Brom-cyclohexenen wurde gezeigt, daß die Reaktion sowohl als einfache nucleophile Substitution des Broms durch Wasserstoff als auch unter Allylumlagerung mit Angriff des Hydridions am C-Atom 1 verläuft. Die in beiden Allylstellungen bromierten cyclischen Olefine reagieren mit Lithiumaluminiumhydrid unter Bildung mehrerer Produkte, die durch Angriff des Hydrids an einem halogentragenden C-Atom (a), an einem olefinischen C-Atom (b) und an einem Brom-atom (c) entstanden sind. Reaktion (a) liefert Monoolefin, (b) ergibt 4-Bromolefin und nach (c) entsteht 1.3-Diolefin. Die Eliminierung nach (c) wurde allerdings nur am unsubstituierten Cyclohexen- und Cycloheptendibromid beobachtet. Für die Eliminierung wird ein weitgehend koplanarer Übergangszustand angenommen, der bei den anderen untersuchten Dibromiden nicht möglich ist.
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    URL: http://dx.doi.org/10.1002/cber.19640970118
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    Desaminierung des 9-Amino-Δ4(10)-octalins (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 165-168 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Desaminierung des 9-Amino-Δ4(10)-octalins in essigsaurer Lösung gibt zu etwa 80% die substituierten Allylalkohole Δ9(10)-Octalol-(1) und Δ4(10)-Octalol-(9) nebst Acetat, sowie die aus diesen durch normale Wasserabspaltung hervorgehenden Hexaline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970122
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    Untersuchungen in der Isothiochroman -Reihe (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 179-185 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Umsetzung von β-Phenäthylmercaptan mit Aldehyden und Chlorwasserstoff entstehen [α-Chlor-alkyl]- β-phenäthyl-sulfide, die mit Aluminium-chlorid unter Ringschluß zu Isothiochromanen reagieren. - 1-Chlor-isothio-chroman, durch Einwirkung von Chlor auf Isothiochroman gewonnen, liefert mit Alkyl- oder Arylmagnesiumhalogeniden 1-Alkyl- bzw. 1-Aryl-isothiochromane, mit Mercaptanen 1-Alkylmercapto-, mit sekundären Aminen 1-Di-alkylamino- und mit Alkoholen 1-Alkoxy-isothiochromane. - Durch Umsetzung der letzteren mit Natriumhydrogensulfit entsteht Isothiochroman-sulfonsäure-(1), die in Isothiochroman-S-dioxid-sulfonsäure-(1) bzw. deren Ester übergeführt werden kann.
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    Zur Kenntnis des 1.2- und 3.4-Benzpyrens (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 218-224 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1.2-Benzpyren gibt der Bromierung das 5.8-Dibromderivat II und bei der Chlorierung das 3.5.8.10-Tetrachlorderivat V. Aus II wird das 5.8-Dinitril III und daraus die entsprechende Dicarbonsäure IV dargestellt. Die Hydrierung des 1.2-Benzpyrens führt zunächst zu einer Hexahydroverbindung, die ein Anthracenderivat ist, und dann zu dem Decahydro-1.2-benzpyren VI, das einen Naphthalinkern enthält. Die Oxydation verläft sehr komplex und liefert neben dunklen Kondensationsprodukten nur geringe Mengen zweier Säuren, die bei der Decarboxylierung Phenanthren und Triphenylen geben. - 3.4-Benzpyren liefert unter milden Bedingungen das 5-Brom-Derivat VII. Weitere Chlorierung von Trichlor-3.4-benzpyren VIII führt zum Trichlor-3.4-benzpyren-tetrachlorid IX.
    Type of Medium: Electronic Resource
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    Mittlere Ringe, XXII. Die Reaktionen der 1.2-Benzo-cyclenyl-(4)-amine mit salpetriger Säure (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 249-254 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Produkte des Zerfalls der 1.2-Benzo-cyclenyl-(4)-diazonium-lonen (II) in Essigsäure werden mit denen der Acetolyse der 1.2-Benzo-cyclenyl-(4)-tosylate (VI) verglichen. Die erste Reaktion vollzieht sich am Beispiel des Vertreters mit 7-gliedrigem Ring mit 53-proz., die zweite mit 89-proz. Konfigurationserhaltung.
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  • 79
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    Oxydation von Thioschwefelsäure durch Thionylchlorid und Sulfurylchlorid (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 282-284 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thioschwefelsäure läß sich mit Thionylchlorid in guten Ausbeuten unter Chlorwasserstoffabspaltung zu einem äquimolaren Gemisch aus Disulfan-disulfonsäure und Trisulfan-disulfonsäure oxydieren. Mit Sulfurylchlorid bildet H2S2O3 neben HCI und Schwefeldioxid reine H2S4O6.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970139
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  • 80
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    Darstellung und Umwandlungen der 4.5.8-Trihydroxy-6-mercapto-chinolin-carbonsäure-(2) (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 285-294 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4.5.8-Trihydroxy-6-mercapto-chinolin-carbonsäure-(2) (II) wird durch Spaltung des Xanthogenats XV mit Aluminiumbromid dargestellt. Die Spaltung von XV mit Bromwasserstoffsäure führt zur reduktiven Abspaltung der Schwefelfunktion. Bei der Methylierung von II mit Diazomethan entsteht neben dem vollmethylierten Chinolinderivat XXI ein Chinolon XXII, bei dem die zur Chinolon-Carbonylgruppe peri-ständige 5-Hydroxygruppe unmethyliert bleibt. II ist wider Erwarten nicht identisch mit einem aus dem Ommochrom „Ommin A“ dargestellten Abbauprodukt.
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    URL: http://dx.doi.org/10.1002/cber.19640970140
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  • 81
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    Notiz über das Verhalten von 2.2.2-Trichlor-1.1-bis-[3.5-dichlor-2-hydroxy-phenyl]-äthan gegenüber Alkali (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 300-301 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970144
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  • 82
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    Über die Oxydation von Pyrogallol und Pyrogalloderivaten, IV. Die Konstitution der Purpurogallin-carbonsäure-(9) (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 307-311 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Oxydation von Pyrogallol in alkoholischer Lösung wird Purpurogallincarbonsäure-(9)-ester gebildet, dessen Konstitution sich aus dem Abbau zu Purpurogallin und Methylterephthalsäure ergibt.
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    URL: http://dx.doi.org/10.1002/cber.19640970202
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  • 83
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    Zur Kenntnis der o-Chinone, XXIV. Synthese, Struktur und Eigenschaften von 1′.2′-Dihydroxy-6.7-benzotropolonen (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 312-324 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1′.2′-Dihydroxy-benzotropolon-Derivate können nach zwei Methoden dargestellt werden: 1.aus 3 Moll. eines o-Benzochinons mit unsubstituierter Doppelbindung und 1 Mol. eines geeigneten Pyrogallolderivates, 2. durch Oxydation eines Gemisches geeigneter Brenzcatechin- und Pyrogallolderivate mit KJO3 bzw. K3[Fe(CN)6]. Bei der Umsetzung von o-Benzochinonen mit 4-Methylpyrogallol wird nur dasjenige Isomere (I a) gebildet, bei welchem die Reaktionspartner im Orientierungskomplex die räumlich günstigste Anordnung (Methylgruppe auf der von der Verknüpfungsstelle abgewandten Seite) haben. Zwei Synthesen für Trimethylpyrogallol und die Darstellung von 2′-Hydroxy-benzotropolon-chinon-(1′.4′) (VIII) werden beschrieben.
    Additional Material: 2 Tab.
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  • 84
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    Über die Darstellung symmetrischer Tetraaryläthane und deren Fähigkeit zur Dissoziation in Radikale (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 349-362 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: symm. Tetra-pyrenyl-(3)-äthan (III), symm. Di-pyrenyl-(3)-diphenyl-äthan (VII), 2.3-Di-[pyrenyl-(3)]-butan (IX), 2.2.5.5-Tetramethyl-3.4-diphenyl-3.4-di-[pyrenyl-(3)]-hexan (X) und Hexa-pyrenyl-(3)-äthan (XI) wurden dargestellt und ihre Fähigkeit zur Dissoziation in Radikale bei Raumtemperatur mit Hilfe der Elektronenspinreasonanz -Method (ESR) untersucht. Mit Ausnahme von 2.3-Di-[pyrenyl-(3)]-butan sind sämtliche der untersuchten Verbindungen bei Raumtemperatur partiell, das Hexa-[pyrenyl-(3)]-äthan erwartungsgemäß quantitativ dissoziiert. Beim symm. Tetra-α-naphthyl-äthan (VIII) ist dagegen keine Radikaldissoziation nachweisbar. - Das von Pyren ausgehend in guter Ausbeute in zweistufiger Synthese darstellbare symm. Tetra-pyrenyl-(3)-äthan ist im organischen Solvens bei Raumtemperatur unlöslich. Es ist im festen Zustand zu 0.0025% in Radikale dissoziiert. - Die Abhängigkeit der Carbonylfrequenz im IR-Spektrum von Mono- und Diarylderivaten des Formaldehyds vom Kondensationsgrad des Arylrestes wurde untersucht.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19640970207
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  • 85
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    Über die Synthese von Pyridazino Pyridazion [3.2-b] chinazolonen-(10) (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 390-395 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 3-Halogen-pyridazine reagieren mit Anthranilsäure oder Anthranilsäure-äthyl-ester zu Pyridazino[3.2-b ]chinazolonen-(10), deren Eigenschaften beschrieben werden.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19640970211
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  • 86
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    Untersuchungen in der Cyclobutanreihe, XII. Zwei stereoisomere Dimere des Cyclobutadiens (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 382-389 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei Eliminierung des Chlors aus cis-3.4-Dichlor-cyclobuten mittels Natriumamalgam in äther. Lösung entsteht das syn-Tricyclo[4.2.0.02.5]octadien-(3.7) (I), identisch mit dem früher aus 1.2.3.4-Tetrabrom-cyclobutan erhaltenen Produkt. Bei ähnlicher Behandlung mit Lithiumamalgam bildet sich überwiegend das isomere anti- Tricycloocatadien (II). Die Ozonspaltung und einige Derivate dieser Kohlenwasserstoffe werden beschrieben.
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    URL: http://dx.doi.org/10.1002/cber.19640970210
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  • 87
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    Die Umsetzung von L-Tryptophan und L-Histidin mit Hexosen) (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 415-418 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Umsetzung von L-Tryptophan mit D-Fructose liefert kristallisierte 2-Nα-L-Tryptophan-2-desoxy-D-glucose(I), mit D-Glucose 1-Nα-L-Tryptophan-1-desoxy-D-fructose (II), Aus L-Histidin und D-Fructose entsteht 2-Nα-L-Histidin-2-desoxy-D-Glucose (II).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970214
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  • 88
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    Über die Reaktionen der Hexacarbonyle der Chromgruppe mit Bipyridyl-(2.2′) und 1.10-Phenanthrolin (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 426-432 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei der Umsetzung der Hexacarbonyle der Chromgruppe mit Bipyridyl-(2.2′) bzw. 1.10-Phenanthrolin geht die Substitution über die Tetracarbonylstufen M(CO)4bipy bzw. M(CO)4phen hinaus, wenn man in hochsiedenden Kohlenwasserstoffen, wie Decalin, Tetralin oder 1-Methyl-naphthalin arbeitet. Während mit Mo(CO6 und W(CO)6 die Dicarbonylverbindungen M(CO)2bipy2 bzw. M(CO)2phen2 gebildet werden, entstehen mit Cr(CO)6 die totalsubstituierten Typen Cr(bipy)3 und Cr(phen)3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970216
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  • 89
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    Zur Kenntnis der Chemie der Metallcarbonyle in flüssigem Ammoniak, XII. Die Reaktionen der Hexacarbonyle der Chromgruppe und ihrer Bipyridyl-(2.2′)- und 1.10-Phenanthrolin-Substitutionsprodukte im Ammonosystem (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 433-442 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die Hexacarbonyle M(CO)6 (M=Cr, Mo, W) setzen sich bei 120° mit flüssigem NH3 zu den Tricarbonyltriamminverbindungen M(CO)3(NH3)3 um; nur beim Cr(CO) 6 ist bei 80° auch Cr(CO)5NH3 zugänglich. Bei den Reaktionen von M(CO)4bipy und M(CO)4phen (bipy = Bipyridyl-(2.2′), phen = 1.10-Phenanthrolin) mit flüssigem NH3 erfolgt bei 120° Substitution einer CO-Molekel unter Bildung der Verbindungstypen M(CO)3 bipyNH3 bzw. M(CO)3phenNH3. Bei den Umsetzungen von M(CO)4bipy mit Kaliumcyanid in flüssigem NH3 wird bei 60° bipy vollständig durch CN⊖ ersetzt. Hierbei werden mit Cr(CO)4bipy K2[Cr0(CO) 4(CN)2], mit Mo(CO)4bipy und W(CO)4bipy unter gleichzeitiger CO-Substitution K3[M0(CO) 3(CN)3] gebildet.
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  • 90
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    Die Friedel-Crafts-Reaktion von Isocyanaten mit Benzolderivaten (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 472-479 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Aryl- und Alkylisocyanate reagieren mit Benzolderivaten unter Friedel-Crafts-Bedingungen zu N-substituierten Benzoesäureamiden. Auch die wenig reaktionsfähigen Halogenbenzole sind der Umsetzung zugänglich.
    Additional Material: 6 Tab.
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    URL: http://dx.doi.org/10.1002/cber.19640970222
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  • 91
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    Zur Epimerisierung von Galanthamin (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 563-565 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Das kürzlich als 2-Hydroxy-4.5-epoxy-6-O-methyl-tetrahydro-apogalanthamin beschriebene Abbauprodukt aus Galanthamin wurde als (-)-Epigalanthamin identifiziert.
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    URL: http://dx.doi.org/10.1002/cber.19640970236
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  • 92
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    Die Polymerisation der Chinonmethide (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 579-587 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Wegen der zentralen Stellung der Chinonmethide in der Chemie des Lignins wurden 3 niedermolekulare p-Chinonmethide auf ihre chemischen Reaktionen und ihre Polymerisation untersucht. Die Polymerisate sind zur monomeren Stufe abzubauen und bestehen aus fortlaufend verätherten p-Hydroxy- benzyl-alkoholen (Polybenzylaryläthern) vom Typus XX.
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    URL: http://dx.doi.org/10.1002/cber.19640970239
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  • 93
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    Geometrische Isomerenpaare mit bevorzugter cis-Struktur, VI. 1.4-Difluor- und 1.4-Dichlor-butadien-(1.3) (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 602-609 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die cis-Formen geometrischer Isomerenpaare scheinen ganz allgemein energie ärmer zu sein, wenn nicht H-H-Wechselwirkung oder extreme Raumbeanspruchung wie beim 1.2-Dijod-äthylen vorliegen. Die Isolierung der geometrischen Isomeren der im Titel genannten Verbindungen erlaubt deren Strukturzuordnung und die Untersuchung der thermischen Gleichgewichte. Die cis-cis-Isomeren sind in Benzollösung energetisch gegenüber den trans-trans-Isomeren stark bevorzugt, welche bei den Meßtemperaturen von 100° und 150° nur zu 10 bis 15% im Gleichgewicht vertreten sind.
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    URL: http://dx.doi.org/10.1002/cber.19640970242
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  • 94
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    Optical Rotatory Dispersion Studies, LXXXVIII. Vergleichende Messungen der Optischen Rotationsdispersion und des Zirkulardichroismus der N-Phthalyl-Derivate von Aminen und α- Aminosäuren (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 533-548 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Messungen der Optischen Rotationsdispersion und des Zirkulardichroismus von N-Phthalyl-aminen beweisen die Existenz von mindestens einer optischaktiven Absorptionsbande im Bereich oberhalb von 300 mμ, die im UV-Spektrum nicht erkennbar ist. Aus dem Vorzeichen der zugehörigen Cotton-Effekt-Kurve kann die absolute Konfiguration bestimmt werden: N-Phthalyl-Derivate optisch-aktiver Amine der (R)-Reihe zeigen einen negativen Cotton-Effekt, solche der (S)-Reihe einen positiven. Entsprechende Messungen an N-Phthalyl-Derivaten von α-Aminosäuren führten zum Nachweis von mindestens zwei optischaktiven Absorptionsbanden, die wiederum im UV-Spektrum nicht erkennbar sind. Die vorliegende Untersuchung stellt ein weiteres Beispiel dar für die Anwendung der Optischen Rotationsdispersion und besonders des Zirkulardichroismus zur Ermittlung verdeckter Absorptionsbanden.
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    URL: http://dx.doi.org/10.1002/cber.19640970233
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    Zur Kenntnis des Cyanformaldehyds (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 566-574 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Bei Versuchen, Cyanformaldehyd herzustellen, wurden bei Raumtemperatur nur Cyanwasserstoff und Kohlenmonoxyd bzw. Ameisensäure erhalten. Dagegen konnten das Oxim und Phenylhydrazon des Cyanformaldehyds, beide in syn- und anti- Form, dargestellt werden. Das Cyanformaldoxim ist extrem unbeständig gegen Basen, die den exothermen Zerfall in Dicyan und Wasser katalysieren. Das Oxim und Phenylhydrazon sowie geeignete Derivate konnten nicht zu Abkömmlingen des s-Triazin-trialdehyds trimerisiert werden.
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    URL: http://dx.doi.org/10.1002/cber.19640970237
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  • 96
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    Über Inhaltsstoffe aus Teak (Tectona grandis L.), II. Konstitution and Synthese des Tectols und Dehydrotectols (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 588-597 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Für die im Teak aufgefundenen Verbindungen Tectol (C30H26O4, I) und Dehydrotectol (C30H24O4, V) konnte die Konstitution durch Abbau, Reaktion mit Acetylendicarbonsäure-dimethylester, Überführung ineinander sowie durch die Synthese des Tetrahydrotectols (IX), Tectols und Dehydrotectols festgelegt werden. V dürfte das erste in der Natur aufgefundene tieffarbige Dehydrodinaphthol sein. Da es in festem Zustande ein schwaches ESR-Signal gibt, liegt es wohl teilweise als Radikal XIII vor. Ein Cyclisierungsprodukt X aus Tectol und andere Verbindungen aus Teak werden beschrieben.
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    URL: http://dx.doi.org/10.1002/cber.19640970240
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  • 97
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    Beiträge zur Chemie des Bors, XXVII. Spaltung der Schwefel-Stickstoff-Bindung in Dialkylamino-sulfanen durch Borchloride (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 709-714 
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    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wird über die Spaltung der Schwefel-Stickstoff-Bindung der Verbindungen CH3SNR2 (R = (CH3, C2H5), [(CH3)2N]2SO durch Borchloride berichtet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970312
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  • 98
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    Über Osonhydrazone, XIV. Darstellung von Osonhydrazon-oximen (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 725-732 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Oson-1-hydrazone und Osazone, die nur asymmetrisch disubstituierte Hydrazinreste enthalten, reagieren mit Hydroxylamin unter Bildung von Oson-1-hydrazon-2-oximen. Mit primären Hydrazinen lassen sich daraus Mischosazone herstellen. Vergleichend wird über entsprechende Derivate des Methylglyoxals berichtet.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970315
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  • 99
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    Über die Bestimmung der Acidität starker Säuren mit Hilfe aliphatischer Diazoverbindungen, I. Synthesen und Infrarotspektren weitgehend säurestabiler aliphatischer Diazoverbindungen (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 735-740 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Einige aliphatische Diazoverbindungen - hauptsächlich aus der Reihe des Diazocyclopentadiens und der Bis-alkyl- bzw. Bis-arylsulfon-diazomethane - mit zum Teil recht hoher Säurestabilität werden dargestellt. Die der NN-Schwingung zuzuordnende Infrarotabsorption im Wellenzahlenbereich um 21OO/cm verschiebt sich mit zunehmender Säurestabilität nach höheren Frequenzen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970317
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  • 100
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    Zur Synthese von pentaarylierten Phosphoranen (1964)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 97 (1964), S. 741-746 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Triphenylphosphin sowie Phenyl-biphenylen-phosphin wurden durch Umsetzung mit Phenylazid und anschließend Methylbromid in die zugehörigen Iminiumbromide I und III übergeführt, die sich bei Einwirkung von Lithiumarylen zu pentaarylierten Phosphoranen abwandeln ließen. Nach diesem neuen Verfahren konnten außer Pentaphenylphosphoran die analogen Verbindungen IV, V und XI präpariert werden.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19640970318
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