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1.
PAPER CURRENT
Chiral Cyclopentadienyls: Enabling Ligands for Asymmetric Rh(III)-Catalyzed C–H Functionalizations (2015)
Publication Date: 2015-04-19
Description: Accounts of Chemical ResearchDOI: 10.1021/acs.accounts.5b00092
Print ISSN: 0001-4842
Electronic ISSN: 1520-4898
Topics: Chemistry and Pharmacology
2.
PAPER CURRENT
Psychosocial interaction during a 105-day isolated mission in Lunar Palace 1 (2015)
Publication Date: 2015-04-19
Description: Publication date: August–September 2015 Source:Acta Astronautica, Volume 113 Author(s): Ruilin Wu , Ya Wang As they are the most important and critical group in space missions, the crewmembers’ emotions and interpersonal interactions have gained attention. The crewmembers are confined in an isolated environment, have limited communication with the outside world, and often undergo unpredictable risks, which may lead to the aggravation and acceleration of depression, displacement, and even interpersonal conflicts. These psychological factors could deteriorate the astronauts׳ effectiveness and safety. Therefore, the aim of the study is to identify the possible patterns over time regarding changes in the emotional states, cohesion and other group dynamics during a 105-day isolation period. The experiment was conducted in an analogue space station at Beihang University, referred to as Lunar Palace 1, which is the first crew made up of all Chinese members. In the experiment, all the crewmembers completed a profile of mood states (POMS) questionnaire every week, along with the group׳s environment scale (GES) and work environment scale (WES) every two weeks. Following the experiment׳s isolation period, semi-structured interviews were also conducted as qualitative data. As a result, the following observations were determined: 1) there was no 3rd quarter phenomenon observed during 80 days isolated experiment for Group 3; and the average positive emotions and cohesion of crew were gradually increased with the process. 2) Significant individual differences were identified; and crewmembers possessed different change patterns on psychological state. 3) Crew structure with 1 male and 2 female, less pre-mission team building, and collectivist culture might influence the psychosocial interaction of crew. In summary, the results from Lunar Palace 1 demonstrated that the emotions and climate of Group 3 was in a good state for a successful mission.
Print ISSN: 0094-5765
Electronic ISSN: 1879-2030
Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
3.
PAPER CURRENT
Nutritional status and ion uptake response of Gynura bicolor DC. between Porous-tube and traditional hydroponic growth systems (2015)
Publication Date: 2015-04-19
Description: Publication date: August–September 2015 Source:Acta Astronautica, Volume 113 Author(s): Minjuan Wang , Yuming Fu , Hong Liu Hydroponic culture has traditionally been used for Bioregenerative Life Support Systems (BLSS) because the optimal environment for roots supports high growth rates. Recent developments in Porous-tube Nutrient Delivery System (PTNDS) also offer high control of the root environment which is designed to provide a means for accurate environmental control and to allow for two-phase flow separation in microgravity. This study compared the effects of PTNDS and traditional hydroponic cultures on biomass yield, nutritional composition and antioxidant defense system (T-AOC, GSH, H2O2 and MDA) of G. bicolor, and ionic concentration (NH4 +, K+, Mg2+, Ca2+, NO 3 − , H 2 PO 4 − , SO 4 2 − ) of nutrient solution during planting period in controlled environment chambers. The results indicated that the biomass production and yield of G. bicolor grown in PTNDS were higher than in hydroponic culture, although Relative water content (RWC), leaf length and shoot height were not significantly different. PTNDS cultivation enhanced calories from 139.5 to 182.3kJ/100g dry matter, and carbohydrate from 4.8 to 7.3g/100g dry matter and reduced the amount of protein from 7.3 to 4.8g/100g dry matter and ash from 1.4 to1.0g/100g dry matter, compared with hydroponic culture. PTNDS cultivation accumulated the nutrition elements of Ca, Cu, Fe and Zn, and reduced Na concentration. T-AOC and GSH contents were significantly lower in PTNDS than in hydroponic culture in the first harvest. After the first harvest, the contents of MDA and H2O2 were significantly higher in PTNDS than in hydroponic culture. However, the activity of T-AOC and GSH and H2O2 and MDA contents had no significant differences under both cultures after the second and third harvest. Higher concentrations of K+, Mg2+ and Ca2+ were found in nutrient solution of plants grown in hydroponics culture compared to PTNDS, wherein lower concentrations of NO 3 − , H 2 PO 4 − and SO 4 2 − occurred. Our results demonstrate that PTNDS culture has more potential to maintain nutritional quality and the optimal root zone environment for G. bicolor compared with hydroponic culture. And further refinements in PTNDS culture would make it a viable alternative for achieving high productivity in a BLSS.
Print ISSN: 0094-5765
Electronic ISSN: 1879-2030
Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
4.
PAPER CURRENT
Cost and risk assessment for spacecraft operation decisions caused by the space debris environment (2015)
Publication Date: 2015-04-19
Description: Publication date: August–September 2015 Source:Acta Astronautica, Volume 113 Author(s): Hanspeter Schaub , Lee E.Z. Jasper , Paul V. Anderson , Darren S. McKnight Space debris is a topic of concern among many in the space community. Most forecasting analyses look centuries into the future to attempt to predict how severe debris densities and fluxes will become in orbit regimes of interest. Conversely, space operators currently do not treat space debris as a major mission hazard. This survey paper outlines the range of cost and risk evaluations a space operator must consider when determining a debris-related response. Beyond the typical direct costs of performing an avoidance maneuver, the total cost including indirect costs, political costs and space environmental costs are discussed. The weights on these costs can vary drastically across mission types and orbit regimes flown. The operator response options during a mission are grouped into four categories: no action, perform debris dodging, follow stricter mitigation, and employ ADR. Current space operations are only considering the no action and debris dodging options, but increasing debris risk will eventually force the stricter mitigation and ADR options. Debris response equilibria where debris-related risks and costs settle on a steady-state solution are hypothesized.
Print ISSN: 0094-5765
Electronic ISSN: 1879-2030
Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
5.
PAPER CURRENT
Study on flame responses and ignition characteristics of CH4/O2/CO2 mixture in a micro flow reactor with a controlled temperature profile (2015)
Publication Date: 2015-04-19
Description: Publication date: 5 June 2015 Source:Applied Thermal Engineering, Volume 84 Author(s): Xing Li , Li Jia , Hisashi Nakamura , Takuya Tezuka , Susumu Hasegawa , Kaoru Maruta A stoichiometric CH4/O2/CO2 (X O2/X CO2 = 0.62) mixture, which has the same laminar burning velocity (36.9 cm/s) as a stoichiometric CH4/air mixture, was tested in a micro flow reactor with a controlled temperature profile. Two kinds of steady flame responses, namely normal flame and weak flame, were observed experimentally in high and low inlet flow velocity regimes, respectively. Dynamic flames termed as FREI (flame with repetitive extinction and ignition) were observed in an intermediate inlet flow velocity regime. The flame responses of the CH4/O2/CO2 (X O2/X CO2 = 0.62) mixture are similar to those of the CH4/air mixture, however, the transition velocities from normal flame to FREI and FREI to weak flame of these two mixtures are different. Moreover, the local wall temperature at the weak flame position of the CH4/O2/CO2 (X O2/X CO2 = 0.62) mixture was found to be 1235 K experimentally, which is 10 K higher than that of the CH4/air weak flame. The local wall temperatures at the weak flame positions of CH4/O2/CO2 (X O2/X CO2 = 0.62) and CH4/air mixtures, obtained by one dimensional computations with GRI-Mech 3.0, are close to those measured by experiments. The flame structure, reaction path and important reactions of the weak flames were analyzed to compare the difference between the CH4/O2/CO2 (X O2/X CO2 = 0.62) and CH4/air weak flames. Although significant chemical effects of CO2 on combustion characteristics of methane premixed flames were reported elsewhere [32–34], it was found that the CH4/O2/CO2 (X O2/X CO2 = 0.62) and CH4/air weak flames do not show significant differences since the chemical effect of CO2 is not strong at relatively low temperatures (below 1300 K).
Print ISSN: 1359-4311
Electronic ISSN: 1873-5606
Topics: Energy, Environment Protection, Nuclear Power Engineering , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Published by Elsevier
6.
PAPER CURRENT
The role of TRPC6 in oxidative stress-induced podocyte ischemic injury (2015)
Publication Date: 2015-04-19
Description: Publication date: Available online 18 April 2015 Source:Biochemical and Biophysical Research Communications Author(s): Bo Zhao , He Yang , Rui Zhang , Hui Sun , Chang Liao , Jia Xu , Kexin Meng , Jundong Jiao Increasing evidence suggests that ischemia and hypoxia serve important functions in the development of renal diseases. However, the underlying mechanism of ischemic injury has not been fully understood. In this study, we found that renal ischemia-reperfusion injury induced podocyte effacement and the upregulation of TRPC6 mRNA and protein expression. In in vitro experiments, oxygen glucose deprivation (OGD) treatment enhanced the expression of TRPC6 and TRPC6-dependent Ca2+ influx. TRPC6 knockdown by siRNA interference attenuated the OGD-induced [Ca2+]i and actin assembly. OGD treatment also increased ROS production. Furthermore, inhibition of ROS activity by N-acetyl-L-cysteine (NAC) eliminated the OGD-induced increase in TRPC6 expression and Ca2+ influx. H2O2 treatment, which results in oxidative stress, also increased TRPC6 expression and Ca2+ influx. We conclude that TRPC6 upregulation is involved in Ca2+ signaling and actin reorganization in podocytes after OGD. These findings provide new insight into the mechanisms underlying the cellular response of podocytes to ischemic injury.
Print ISSN: 0006-291X
Electronic ISSN: 1090-2104
Topics: Biology , Chemistry and Pharmacology , Physics
Published by Elsevier
7.
PAPER CURRENT
SNP identification and marker assay development for high-throughput selection of soybean cyst nematode resistance (2015)
Publication Date: 2015-04-19
Description: Background:Soybean cyst nematode (SCN) is the most economically devastating pathogen of soybean. Two resistance loci, Rhg1 and Rhg4 primarily contribute resistance to SCN race 3 in soybean. Peking and PI 88788 are the two major sources of SCN resistance with Peking requiring both Rhg1 and Rhg4 alleles and PI 88788 only the Rhg1 allele. Although simple sequence repeat (SSR) markers have been reported for both loci, they are linked markers and limited to be applied in breeding programs due to accuracy, throughput and cost of detection methods. The objectives of this study were to develop robust functional marker assays for high-throughput selection of SCN resistance and to differentiate the sources of resistance.Results:Based on the genomic DNA sequences of 27 soybean lines with known SCN phenotypes, we have developed Kompetitive Allele Specific PCR (KASP) assays for two Single nucleotide polymorphisms (SNPs) from Glyma08g11490 for the selection of the Rhg4 resistance allele. Moreover, the genomic DNA of Glyma18g02590 at the Rhg1 locus from 11 soybean lines and cDNA of Forrest, Essex, Williams 82 and PI 88788 were fully sequenced. Pairwise sequence alignment revealed seven SNPs/insertion/deletions (InDels), five in the 6th exon and two in the last exon. Using the same 27 soybean lines, we identified one SNP that can be used to select the Rhg1 resistance allele and another SNP that can be employed to differentiate Peking and PI 88788-type resistance. These SNP markers have been validated and a strong correlation was observed between the SNP genotypes and reactions to SCN race 3 using a panel of 153 soybean lines, as well as a bi-parental population, F5–derived recombinant inbred lines (RILs) from G00-3213 x LG04-6000.Conclusions:Three functional SNP markers (two for Rhg1 locus and one for Rhg4 locus) were identified that could provide genotype information for the selection of SCN resistance and differentiate Peking from PI 88788 source for most germplasm lines. The robust KASP SNP marker assays were developed. In most contexts, use of one or two of these markers is sufficient for high-throughput marker-assisted selection of plants that will exhibit SCN resistance.
Electronic ISSN: 1471-2164
Topics: Biology
Published by BioMed Central
8.
PAPER CURRENT
Metformin reduces the endotoxin-induced down-regulation of apolipoprotein E gene expression in macrophages (2015)
Publication Date: 2015-04-19
Description: Publication date: Available online 18 April 2015 Source:Biochemical and Biophysical Research Communications Author(s): Simona Stavri , Violeta G. Trusca , Maya Simionescu , Anca V. Gafencu The atheroprotective role of macrophage-derived apolipoprotein E (apoE) is well known. Our previous reports demonstrated that inflammatory stress down-regulates apoE expression in macrophages, aggravating atherogenesis. Metformin, extensively used as anti-diabetic drug, has also anti-inflammatory properties, and thus confers vascular protection. In this study, we questioned whether metformin could have an effect on apoE expression in macrophages in normal conditions or under lipopolysaccharide (LPS)-induced stress. The results showed that metformin slightly increases the apoE expression only at high doses (5-10 mM). Low doses of metformin (1-3 mM) significantly reduce the LPS down-regulatory effect on apoE expression in macrophages. Our experiments demonstrated that LPS-induced NF-κB binds to the macrophage-specific distal regulatory element of apoE gene, namely to the multienhancer 2 (ME.2) and its 5’-deletion fragments. The NF-κB binding on ME.2 and apoE promoter has a down-regulatory effect. In addition, data revealed that metformin impairs NF-κB nuclear translocation, and thus, improves the apoE levels in macrophages under inflammatory stress. The positive effect of metformin in the inflammatory states, its clinical safety and low cost, make this drug a potential adjuvant in the therapeutic strategies for atherosclerosis.
Print ISSN: 0006-291X
Electronic ISSN: 1090-2104
Topics: Biology , Chemistry and Pharmacology , Physics
Published by Elsevier
9.
PAPER CURRENT
Nonlocal thermo-mechanical vibration analysis of functionally graded nanobeams in thermal environment (2015)
Publication Date: 2015-04-19
Description: Publication date: August–September 2015 Source:Acta Astronautica, Volume 113 Author(s): Farzad Ebrahimi , Erfan Salari In this paper, the thermal effect on free vibration characteristics of functionally graded (FG) size-dependent nanobeams subjected to various types of thermal loading is investigated by presenting a Navier type solution and employing a semi analytical differential transform method (DTM) for the first time. Two kinds of thermal loading, namely, linear temperature rise and nonlinear temperature rise are studied. Material properties of FG nanobeam are supposed to vary continuously along the thickness according to the power-law form and the material properties are assumed to be temperature-dependent. The small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. The nonlocal equations of motion are derived through Hamilton׳s principle and they are solved applying DTM. According to the numerical results, it is revealed that the proposed modeling and semi analytical approach can provide accurate frequency results of the FG nanobeams as compared to analytical results and also some cases in the literature. The detailed mathematical derivations are presented and numerical investigations are performed while the emphasis is placed on investigating the effect of the several parameters such as thermal effect, material distribution profile, small scale effects, mode number and boundary conditions on the normalized natural frequencies of the temperature-dependent FG nanobeams in detail. It is explicitly shown that the vibration behaviour of a FG nanobeams is significantly influenced by these effects. Numerical results are presented to serve as benchmarks for future analyses of FG nanobeams.
Print ISSN: 0094-5765
Electronic ISSN: 1879-2030
Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
10.
PAPER CURRENT
Experimental investigation of flow through planar double divergent nozzles (2015)
Publication Date: 2015-04-19
Description: Publication date: July–August 2015 Source:Acta Astronautica, Volume 112 Author(s): Rajat Arora , Aravind Vaidyanathan Dual bell nozzle is one of the feasible and cost effective techniques for altitude adaptation. Planar double divergent nozzle with a rectangular cross section was designed for two different NPR׳s to simulate and investigate the flow regimes similar to those inside the dual bell nozzle. Measurements involved flow visualization using Schlieren technique and wall static pressure measurements. The flow transition between the two nozzles at the respective inflection points and the formation of recirculation region due to flow separation was analyzed in detail. Cold flow tests were performed on the double divergent nozzle in the over-expanded conditions to study the shock wave characteristics. The results obtained from the two independent double divergent nozzles were compared with those obtained from a single divergent nozzle of the same area ratio. From the experiments it was observed that inflection angle played a key role in defining the type of shock structures existing inside the double divergent nozzles.
Print ISSN: 0094-5765
Electronic ISSN: 1879-2030
Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics