ALBERT

Description: Aims Afforestation causes important alterations in SOM content and composition that affect the soil functions and C balance. The aim of this study was to identify the mechanisms that determine the changes in SOM composition following afforestation of grasslands. Methods The study included 4 chronosequences and 5 paired plots comprising pastures and land afforested with Pinus radiata . The SOM was characterized by 13 C CP-MAS NMR spectroscopy and differential scanning calorimetry. Results During the first 10–20 year after afforestation, the changes in SOM content varied from slight gains to large losses (〉40 %). The analyses revealed that even SOM compounds considered resistant to decomposition were degraded during this time. The SOM gains, observed 20 year after stand establishment, were favoured by the higher recalcitrance of pine litter and possibly by soil acidification. The concentrations of most SOM compounds, particularly the stable compounds, were higher at the end of the rotation. The low degree of protection, along with the favourable climatic conditions, may also explain the rapid decomposition of SOM, including resistant compounds, in these soils. DSC analysis complemented the information about SOM composition provided by other techniques. Conclusions The accumulation of stable SOM compounds at the end of the rotation suggests a longer soil C turnover in these afforested soils, which may alleviate the gradual loss of SOC in intensively managed forest soils.

Description: Background and aims Plant nutrient uptake from coarse soil (2–4 mm diameter) has been demonstrated for only a limited number of nutrients, and the nutritional contribution of coarse soil when present with fine soil (material 〈2 mm diameter) in realistic ratios is unknown. We conducted a seedling pot trial to investigate the functional relevance of this soil fraction to plant nutrition. Methods Fine soil was mixed with either coarse soil, or the equivalent volume of inert glass chips, in ratios identical to those occurring naturally in soil sampled from two depths at each of two sites. Seedlings of Nothofagus solandri var. cliffortioides and Weinmannia racemosa were planted in the soil mixtures and harvested after 9 months. Results The content of nitrogen, phosphorous, potassium, magnesium and other elements in the above ground seedling tissue was significantly increased by the presence of coarse soil. The coarse soil fraction also contributed proportionally much more to plant nutrient uptake than fine soil on a mass per mass basis. Conclusions Coarse soil is excluded from conventional soil analysis, so is possible that soil nutrient capital is systematically underestimated. This has implications for land management and studies of plant dynamics in relation to nutrient supply.

Description: Background and aims Lateral tree-scale variability in plantations should be taken into account when scaling up from point samples, but appropriate methods for sampling and calculation have not been defined. Our aim was to define and evaluate such methods. Methods We evaluated several existing and new methods, using data for throughfall, root biomass and soil respiration in mature oil palm plantations with equilateral triangular spacing. Results Three ways of accounting for spatial variation within the repeating tree unit (a hexagon) were deduced. For visible patch patterns, patches can be delineated and sampled separately. For radial patterns, measurements can be made in radial transects or a triangular portion of the tree unit. For any type of pattern, including unknown patterns, a triangular sampling grid is appropriate. In the case studies examined, throughfall was 79 % of rainfall, with 95 % confidence limits being 62 and 96 % of rainfall. Root biomass and soil respiration, measured on a 35-point grid, varied by an order of magnitude. In zones with steep gradients in parameters, sampling density has a large influence on calculated mean values. Conclusions The methods defined here provide a basis for representative sampling and calculation procedures in studies requiring scaling up from point sampling, but more efficient methods are needed.

Description: In this paper, we have designed, fabricated and characterized silicon nitride grating couplers with high efficiency at 1490 nm. The devices are fabricated using deep UV photolithography with resolution requirement of ∼500 nm. The grating coupler fabricated yields a peak coupling efficiency of −5.1 dB. The 1-dB bandwidth of the grating coupler is 60 nm.

Description: We report on the defect-dominated light emission and ultraviolet (UV) photoconductivity characteristics of ZnO nanorods (NRs) fabricated using a facile, cost-effective, and catalyst-free thermal decomposition route under varying reaction temperatures. The morphological and structural studies reveal the formation of homogeneous quality nanorods in large scale at the highest reaction temperature of 600  ∘ C. The luminescence feature of the nanorods is dominated by the defect related emission over the typical band edge emission. The variation of band-edge and native defect-related emission response of the samples has been correlated to the morphology and microstructure. In photoconductivity studies, the I – V characteristics of the ZnO NRs prepared at different reaction temperatures in dark and under UV illumination ( λ =365 nm) follow the power law, i.e., IαV r . An enhanced ultraviolet photodetection has been observed in the nanorods fabricated at the highest reaction temperature of 600  ∘ C. The sample prepared at highest reaction temperature of 600  ∘ C exhibits UV photosensitivity value (photo-to-dark current ratio) of around 1.18×10 3 , which is much higher in magnitude compared to that of the samples prepared at lower reaction temperatures. The enhanced photoconductivity may be assigned to the development of uniformity and homogeneity of the nanorods. Further development of such ZnO nanostructures can form the basis of promising prototype luminescent and UV photodetecting devices.

Description: Background Plants must acquire at least 14 mineral nutrients from the soil to complete their life cycles. Insufficient availability or extreme high levels of the nutrients significantly affect plant growth and development. Plants have evolved a series of mechanisms to adapt to unsuitable growth conditions where nutrient levels are too low or too high. microRNAs (miRNAs), a class of small RNAs, are known to mediate post-transcriptional regulation by transcript cleavage or translational inhibition. Besides regulating plant growth and development, miRNAs are well documented to regulate plant adaptation to adverse environmental conditions including nutrient stresses. Scope In this review, we focus on recent progress in our understanding of how miRNAs are involved in plant response to stresses resulting from deficiency in nutrients, such as nitrogen, phosphorus, sulfur, copper and iron, as well as toxicities from heavy metal ions. Conclusions Accumulated evidence indicates that miRNAs play critical roles in sensing the abundance of nutrients, controlling nutrient uptake and phloem-mediated long-distance transport, and nutrient homeostasis. miRNAs act as systemic signals to coordinate these physiological activities helping plants respond to and survive nutrient stresses and toxicities. Knowledge about how miRNAs are involved in plant responses to nutrient stresses promise to provide novel strategies to develop crops with improved nutrient use efficiency which could be grown in soils with either excessive or insufficient availability of nutrients.

Description: Background and aims (i) compare the concentrations of total polyphenols (TP) and condensed tannins (CT), and CT profiles in different organs of mature trees and seedlings of eight true mangrove species in Hong Kong; (ii) examine the antioxidant activities of CT and (iii) relate the non-enzymatic antioxidative defence system with the vertical zonation pattern of mangrove species. Methods Mature trees and seedlings of eight species were collected from a Hong Kong mangrove swamp to determine TP and CT concentrations and the antioxidant activities of CT. Results According to TP concentrations, the true mangrove species could be broadly classified into three groups, (i) Lumnitzera racemosa and Aegiceras corniculatum 〉 (ii) Heritiera littoralis , Excoecaria agallocha , Bruguiera gymnorrhiza and Kandelia obovata 〉 (iii) Acanthus ilicifolius and Avicennia marina . The last two are pioneer species in the most foreshore location. They also had significantly lower antioxidant activities, CT concentrations and different CT profiles than the other six species in mid- and low-tides. Conclusions Classification of the eight true mangrove species into three groups based on polyphenols was similar to their vertical zonation from land to sea. The relationships between these antioxidants and zonation should be further verified by transplantation studies.

Description: Background and aims Soil phosphorus (P) indices that have been originally developed and applied to agricultural soils for predicting P uptake by plants were examined in a pot experiment to determine the most suitable index for P availability in bauxite-processing residue sand (BRS). Methods Pot trials with ryegrass were established using BRS that had been amended with various organic (greenwaste compost, biochar and biosolids) and inorganic (zeolite) materials and different levels of di-ammonium phosphate fertiliser. Soil P availability indices tested included anion-exchange membrane (AEM-P), 0.01 M calcium chloride (CaCl 2 -P), Colwell-P, and Mehlich 3-P. Results AEM-P was found to most closely reflect the available P status in BRS across all treatments, and had the strongest associations with plant P uptake compared to Colwell-P, Mehlich 3-P and CaCl 2 -P. AEM-P was more closely correlated with P uptake by ryegrass than other P indices, while Colwell-P was closely related to leaf dry matter. Interestingly, a strong inverse relationship between plant indices and pH in BRS growth media was observed, and an adequate level of plant P uptake was found only in 15 year-old rehabilitated BRS with pH 〈 8.0. Conclusions AEM-P was found to be the most suitable index for evaluating P availability in highly alkaline BRS and pH was an important parameter affecting uptake of P by ryegrass. Importantly, time is required (〉 5 years) before improved uptake of P by plants can be observed in rehabilitated residue sand embankments.

Description: Background & aims Herbivore-driven changes to soil properties can influence the decomposition rate of organic material and therefore soil carbon cycling within grassland ecosystems. We investigated how aboveground foraging mammalian and invertebrate herbivores affect mineral soil decomposition rates and associated soil properties in two subalpine vegetation types (short-grass and tall-grass) with different grazing histories. Methods Using exclosures with differing mesh sizes, we progressively excluded large, medium and small mammals and invertebrates from the two vegetation types in the Swiss National Park (SNP). Mineral soil decomposition rates were assessed using the cotton cloth (standard substrate) method between May and September 2010. Results Decomposition displayed strong spatio-temporal variability, best explained by soil temperature. Exclusion of large mammals increased decomposition rates, but further exclusion reduced decomposition rates again in the lightly grazed (tall-grass) vegetation. No difference among treatments was found in the heavily grazed (short-grass) vegetation. Heavily grazed areas had higher decomposition rates than the lightly grazed areas because of higher soil temperatures. Microbial biomass carbon and soil C:N ratio were also linked to spatio-temporal decomposition patterns, but not to grazing history. Conclusions Despite altering some of the environmental controls of decomposition, cellulose decomposition rates in the SNP’s subalpine grasslands appear to be mostly resistant to short-term herbivore exclusion.

Description: Background Our recent publication (Warren et al., Plant Soil 366:683–693, 2013 ) described how pulses of deuterium oxide (D 2 O) or H 2 O combined with neutron radiography can be used to indicate root water uptake and hydraulic redistribution in maize. This technique depends on the large inherent differences in neutron cross-section between D and H atoms resulting in strong image contrast. Scope and Conclusions However, as illustrated by Carminati and Zarebanadkouki ( 2013 ) there can be a change in total water content without a change in contrast simply by a change in the relative proportions of D 2 O and H 2 O. We agree with their premise and detailed calculations (Zarebanadkouki at al. 2012 , 2013 ), and present further evidence that mixing of D 2 O and H 2 O did not confound evidence of hydraulic redistribution in our study.

Description: Background and aims The growth of green plants depends not only on photosynthesis, but also on the successful remobilization and translocation of seed phosphorus (P) reserves to the vegetative parts of the developing seedling during early growth. Remobilization and photosynthesis are therefore two parallel and co-coinciding processes involved in better seedling establishment and early growth. Methods A study was conducted to evaluate the priority of developing maize seedlings to translocate the remobilized seed P reserves and external P uptake to seedling root and shoot sinks during 4 weeks of early growth. Two fluxes of P in growing seedlings, one from seed remobilized P reserves and one from external P uptake, were distinguished by labelling external nutrient solution P with 32 P. Results The seedling phytomass was equally distributed between seedling roots and shoots for 530 cumulated degree days after sowing. Seedlings partitioned up to 71 % of P from seed reserves and up to 68 % of P acquired from the nutrient solution, to the shoots, depending on the seed P content and P concentration in the nutrient solution. It appears that accumulation of P slows down in seedling roots corresponds to the translocative functions of root P towards shoots for start of photosynthesis. Conclusions Our results suggest that the major part of seed P reserves and external P uptake were used in early development of the seedling and the preferred sink was seedling shoots.

Description: Background and aims Nickel (Ni) has become a major heavy metal contaminant. The form of nitrogen nutrition remarkably affects IRT1 expression in roots. IRT1 has an activity of transporting Ni 2+ into root cells. Therefore, nitrogen-form may affect Ni accumulation and toxicity in plants. The assumption was investigated in this study. Methods The Arabidopsis plants were treated in Ni-contained growth solutions with either nitrate (NO 3 − ) or ammonium (NH 4 + ) as the sole N source. After 7-day treatments, Ni concentration, IRT1 expression, Ni-induced toxic symptoms and oxidative stress in plants were analyzed. Results The NO 3 − -fed plants contained a higher Ni concentration, had a greater IRT1 expression in roots, and developed more severe toxic symptoms in the youngest fully expanded leaves, compared with the NH 4 + -fed plants. The Ni-induced growth inhibition was also more significant in NO 3 − -fed plants. Interestingly, Ni exposure resulted in greater hydrogen peroxide (H 2 O 2 ) and superoxide radical (O 2 . − ) accumulations, more severe lipid peroxidation and more cell death in NO 3 − -fed plants, whereas the opposite was true for NH 4 + -fed plants. Furthermore, the Ni-enhanced peroxidase (POD) and superoxide dismutase (SOD) activities were greater in NO 3 − -fed plants Conclusion NO 3 − nutrition promotes Ni uptake, and enhances Ni-induced growth inhibition and oxidative stress in plants compared with NH 4 + nutrition.

Description: Background and aims Brassica napus has high boron (B) demand, but significant genotype differences exist with respect to B deficiency. The aim of this research was to elucidate the relationship between the different sensitivities of Brassica napus cultivars to low B stress and the characteristics of B uptake and transport to characterise the regulation of B efficiency in Brassica napus . Methods B-efficient and B-inefficient Brassica napus cultivars were used to compare the uptake and transport of B using the stable isotope 10 B tracer and grafting experiments, as well as expression of B transporters by RT-PCR. Results B-efficient cultivars have significant advantages with regard to B limitation. The B-efficient cultivar HZ showed less severe B deficiency symptoms and higher dry biomass than the B-inefficient cultivars LW and LB. Both the amount of total B and the 10 B concentration and accumulation in the shoots and roots of B-efficient HZ were higher than those of B-inefficient cultivars. In B-inefficient LW, the amount of total B and the 10 B that was transported into shoots was less than in the other three cultivars and the content and accumulation of total B and 10 B in the roots of B-inefficient LB were the lowest among all of the cultivars. When the roots of B-efficient HZ were used as stocks, the grafted plants showed B-efficient characteristics, such as mild B deficiency symptoms, and higher dry biomass and B accumulation, regardless of whether they originated from B-efficient or B-inefficient cultivars. In contrast, the grafted plants with B-inefficient LW used as stocks were B-inefficient. The expressions of BnBOR1;1c , BnBOR1;2a and BnNIP5;1 were up-regulated in roots under low B stress compared with the normal B condition. However, there was no obvious difference in the expressions of the three genes or of four other BnBOR1s between B-efficient and B-inefficient cultivars in low or normal B environments. Conclusions These results indicate that the B efficiency of Brassica napus is controlled primarily by roots, which allow more uptake and accumulation of B in B-efficient cultivars than B-inefficient cultivars in a low B environment. However the molecular mechanism regulating B efficiency in Brassica napus remains to be determined.

Description: Aims Application of carbon (C) and nitrogen (N) isotopes is an essential tool to study C and N flows in plant-soil-microorganisms systems. When targeting single plants in a community the tracers need to be added via e.g., leaf-labeling or stem-feeding approaches. In this study we: (i) investigated if bicarbonate can be used to introduce 14 C (or 13 C) into white clover and ryegrass, and (ii) compared the patterns of 14 C and 15 N allocation in white clover and ryegrass to evaluate the homogeneity of tracer distribution after two alternative labeling approaches. Methods Perennial ryegrass and white clover were pulse labeled with 15 N urea via leaf-labeling and 14 C either via a 14 CO 2 atm or with 14 C bicarbonate through leaf-labeling. Plants were sampled 4 days after labeling and prepared for bulk isotope analysis and for 14 C imaging to identify plant parts with high and low 14 C activity. Subsequently, plant parts with high and low 14 C activity were separated and analyzed for 15 N enrichment. Results Bicarbonate applied by leaf-labeling efficiently introduced 14 C into both white clover and ryegrass, although the 14 C activity in particular for white clover was found predominantly in the labeled leaf. Using 14 C imaging for identification of areas with high (hotspots) and low 14 C activity showed that 14 C was incorporated very heterogeneously both when using bicarbonate and CO 2 as expected when using pulse labeling. Subsequent analysis of 15 N enrichment in plant parts with high and low 14 C activity showed that 15 N also had a heterogeneous distribution (up to two orders of magnitude). Conclusion Bicarbonate can efficiently be used to introduce 14 C or 13 C into plant via the leaf-labeling method. Both 14 C and 15 N showed heterogeneous distribution in the plant, although the distribution of 15 N was more even than that of 14 C.

Description: Background and aim In numerous areas, rice cultivated under flooded conditions is exposed simultaneously to iron excess and arsenic contamination. The impact of these combined stresses on yield-related parameters and As distribution and speciation in various plant parts remains poorly documented. Methods Rice (cv I Kong Pao) was exposed to iron excess (125 mg L −1 Fe 2 SO 4 ), arsenic (50 and 100 μM Na 2 HAsO 4 .7H 2 O) or a combination of those stressing agents in hydroponic culture until harvest. Plant growth, yield-related parameters, non protein thiols concentration and mineral nutrition were studied in roots and shoots. Arsenic speciation was determined by high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry. Key Results Iron excess increased As retention by the roots in relation to the development of the root iron plaque but decreased As accumulation in the shoot. Arsenic concentration was lower in the grains than in the shoots. Iron stress reduced As accumulation in the husk but not in the dehusked grains. Iron excess decreased the proportion of extractable As(III) and As(V) in the grain while it increased the proportion of extractable As(III) in the shoot. Combined stresses (Fe+As) affected plant nutrition and significantly reduced the plant yield by limiting the number of grains per plant and the grain filling. Conclusions Fe excess had an antagonist impact on shoot As concentration but an additive negative impact on several yield-related parameters. Iron stress influences both As distribution and As speciation in rice.

Description: Background and aims Intermittently frozen ground in winter is expected to disappear over large areas in the temperate zone due to ongoing climate warming. The lack of soil frost influences plant soil interactions and needs to be studied in more detail. Methods Winter soil frost was avoided by belowground heating wires in a field experiment over two subsequent winters in a temperate grassland. Soil respiration, soil nitrogen availability and plant performance (aboveground biomass, root length at two depth levels, greenness, nutrient content) were compared between “no-frost” and reference plots which underwent repeated freeze-thaw cycles in both winters. Results Soil respiration increased in the “no-frost” treatment during the warming phase (+291 %). N-availability in the upper 10 cm of the soil profile was not affected, possibly due to increased plant N accumulation during winter (+163 %), increased plant N concentration (+18 %) and increased biomass production (+31.5 %) in the growing season. Translocation of roots into deeper soil layers without changes in total root length in response to the “no-frost” treatment, however, may be a sign of nutrient leaching. Conclusions The cumulative effect on carbon cycling due to warmer soils therefore depends on the balance between increased winter carbon loss due to higher soil biotic activity and enhanced plant productivity with higher nutrient accumulation in the growing season.

Description: Aims The aims of this work were to investigate the aluminum (Al) and phosphate (P) interactions in the regulation of root system architecture of Arabidopsis thaliana seedlings and the contribution of auxin signaling in primary and lateral root growth in response to Al toxicity. Methods Detailed analyses of root system architecture and cell division were performed in Arabidopsis WT seedlings and in low phosphorus insensitive mutants lpi1 - 3 and lpr1 - 1 lpr2 - 1 in response to Al. Expression studies of P-deficiency regulated phosphate transporter AtPT2 were also conducted. The role of auxin as a mediator of root morphogenetic changes by Al was evaluated by using the auxin-signaling mutants tir1 , tir1 afb2 afb3 , and arf7 arf19 . Results Al inhibited primary root growth by affecting cell cycle progression and causing differentiation of cells in the root meristem. These effects were reduced in low phosphorus insensitive lpi1 - 3 and low phosphate resistant lpr1 - 1 lpr2 - 1 Arabidopsis mutants. Al also activated the expression of the low phosphate-induced P transporter AtPT2 in roots. Lateral root formation by Al decreased in tir1 afb2 afb3 while arf7 arf19 mutants were highly resistant to Al in both primary root inhibition and lateral root induction. Conclusions Our results suggest that lateral root formation in response to Al toxicity and P deficiency may involve common signaling mechanisms, while a pathway involving ARF7 and ARF19 is important for primary root growth inhibition by Al.

Description: Aims Litter decomposition and subsequent nutrient release play a major role in forest carbon and nutrient cycling. To elucidate how soluble or bulk nutrient ratios affect the decomposition process of beech ( Fagus sylvatica L.) litter, we conducted a microcosm experiment over an 8 week period. Specifically, we investigated leaf-litter from four Austrian forested sites, which varied in elemental composition (C:N:P ratio). Our aim was to gain a mechanistic understanding of early decomposition processes and to determine microbial community changes. Methods We measured initial litter chemistry, microbial activity in terms of respiration (CO 2 ), litter mass loss, microbial biomass C and N (C mic and N mic ), non purgeable organic carbon (NPOC), total dissolved nitrogen (TDN), NH 4 + , NO 3 - and microbial community composition (phospholipid fatty acids – PLFAs). Results At the beginning of the experiment microbial biomass increased and pools of inorganic nitrogen (N) decreased, followed by an increase in fungal PLFAs. Sites higher in NPOC:TDN (C:N of non purgeable organic C and total dissolved N), K and Mn showed higher respiration. Conclusions The C:N ratio of the dissolved pool, rather than the quantity of N, was the major driver of decomposition rates. We saw dynamic changes in the microbial community from the beginning through the termination of the experiment.

Description: Background and aims Grazing may influence nutrient cycling in several ways. In productive mountain grasslands of central Argentina cattle grazing maintain a mosaic of different vegetation patches: lawns, grazed intensively and dominated by high quality palatable plants, and open and closed tussock grasslands dominated by less palatable species. We investigated if differences in the resources deposited on soil (litter and faeces) were associated with litter decomposition rates and soil nitrogen (N) availability across these vegetation patches. Methods We compared the three vegetation patches in terms of litter and faeces quality and decomposability, annual litterfall and faeces deposition rate. We determined decomposition rates of litter and faces in situ and decomposability of the same substrates in a common garden using “litter bags”. We determined soil N availability (with resin bags) in the vegetation patches. Also, we performed a common plant substrates decomposition experiment to assess the effect of soil environment on decomposition process. This technique provides important insights about the soil environmental controls of decomposition (i.e. the sum of soil physicochemical and biological properties, and microclimate), excluding the substrate quality. Results The litter quality and faeces deposition rate were higher in grazing lawns, but the total amounts of carbon (C) and nitrogen (N) deposited on soil were higher in tussock grasslands, due to higher litterfall in these patches. The in situ decomposition rates of litter and faeces, and of the two common plant substrates were not clearly related to either grazing pressure, litterfall or litter quality (C, N, P, lignin, cellulose or hemicellulose content). In situ litter decomposition rate and soil ammonium availability were correlated with the decomposition rates of both common plant substrates. This may suggest that difference in local soil environment among patch types is a stronger driver of decomposition rate than quality or quantity of the resource that enter the soil. Conclusions Our results show that, although high grazing pressure improves litter quality and increases faeces input, the reduction in biomass caused by herbivores greatly reduces C and N input for the litter decomposition pathway. We did not find an accelerated decomposition rate in grazing lawns as proposed by general models. Our results point to soil environment as a potential important control that could mask the effect of litter quality on field decomposition rates at local scale.

Description: Background and aims Cd uptake has been shown to increase during conditions of Fe deficiency. This study tested the hypothesis that Fe-deficiency-responsive genes, particularly OsNRAMP1, play a role in the increased Cd uptake that occurs when rice is grown in aerobic soil conditions. Methods Plants were grown in aerobic or flooded soil conditions. Uptake of Cd was compared to levels of expression of candidate metal transporters and to metal ion availability in soil. Results Plants grown with intermittent soil flooding experienced a predominantly aerobic root environment and had the highest plant Cd uptake. Stronger upregulation of OsNRAMP1 was detected in plants grown in unflooded soil than in flooded soil. However, these transcriptional responses were not linked to an increase in Cd uptake. Overexpression of OsNRAMP1 was not found to increase the uptake of Cd in rice in soil or solution culture. In contrast, there were large differences in availability of Cd, Fe and Mn between flooded and aerobic soils, which were linked to changes in Cd uptake. Conclusions Aerobic soil conditions favour Cd uptake through increased Cd availability and decreased competition between Cd and Fe rather than through the increased expression of the Fe transporters themselves.

Description: Background and aims Intensive land use has led to degradation and abandonment of Portuguese oak woodlands, and subsequent shrub encroachment may have altered the spatial heterogeneity of soil C and N pools. The aim of this study was to evaluate the effects of shrub invasion on soil C and N dynamics in an oak woodland in Southern Portugal. Methods Soil was sampled beneath and outside scattered Quercus suber L. canopies, considering non-encroached areas and areas encroached by shrubs ( Cistus ladanifer L. or Cistus salviifolius L.). Results The spatial heterogeneity of soil C and N contents was mainly associated with tree presence. Outside tree canopies, the labile C pools were larger (mainly beneath C . ladanifer ) and C cycling was faster in encroached areas than in non-encroached areas. Net and gross N mineralization and urease and protease activities were also higher in encroached than in non-encroached areas; however, the metabolic quotient and the Cmicrobial/Corganic ratio were not significantly affected. Beneath the tree canopy, significant effects of encroachment included a small increase in soil labile C and the enzymatic activity beneath C . ladanifer . Conclusions The results indicate the potential capacity of shrub encroachment to accumulate soil organic C in the long term. The rate of soil C and N turnover promoted by shrub encroachment may depend on the Cistus species present.

Description: Aims Decreased expression of TaNAM genes by RNAi results in delayed senescence and decreased grain protein, iron, and zinc concentrations. Here, we determined whether NAM expression level alters onset of senescence under stress conditions, whether delayed senescence in the TaNAM -RNAi line resulted in improved tolerance to post-anthesis abiotic stress, and determined the effects of post-anthesis abiotic stress on N and mineral remobilization and partitioning to grain. Methods Greenhouse-grown WT and TaNAM -RNAi wheat were characterized in two studies:three levels of N fertility or water limitation during grain fill. Studies were conducted under both optimal and heat stress temperatures. Senescence onset was determined by monitoring flag leaf chlorophyll. Results Under optimal tempertures, TaNAM -RNAi plants had a yield advantage at lower N. TaNAM -RNAi plants had delayed senescence relative to the WT and lower grain protein and mineral concentrations, N remobilization efficiency, and partitioning of N and most minerals to grain. Conclusions Nutritional quality of TaNAM -RNAi grain was consistently lower than WT. Delayed senescence of TaNAM -RNAi plants provided a yield advantage under optimal temperatures but not under water or heat stress. Discovery of specific NAM protein targets may allow separation of the delayed senescence and nutrient partitioning traits, which could be used for improvement of wheat.

Description: Aims Nitrification inhibitors (NI) formulated on granulated ammonium sulphate nitrate (ASN) are an option to minimize nitrate leaching into ground waters and emissions of the greenhouse gas N 2 O. This paper focuses (a) on the development of an analytic enabling to extract and quantify the NI 3,4-dimethylpyrazolephosphate (DMPP), marketed since 1999. The efficiency of DMPP has been studied in laboratory and field soils. Here the DMPP analytic and the behaviour of a nitrifying bacterial consortium enriched from a field soil and exposed to zero, field applied and a 10 fold higher DMPP concentration than the recommended one for field application are in the focus. Methods For extracting DMPP quantitatively from soils a method connected to a HPLC analytic has been developed by us and was standardized in laboratory experiment with a silt clay field soil (allochtone Vega). The method is detailed described here. Its reliability has been tested in a 3 years field trial under varying cropping systems and climatic conditions asides the influence of DMPP on CO 2 −, CH 4 − and N 2 O- emissions, measured by the closed chamber method. Parallel a nitrifying bacterial consortium of the silty clay field soil was enriched and subjected to 0, the recommended DMPP concentration for field applications and a 10 times higher one. In incubation experiments the conversion of ammonium to nitrite and nitrate in presence and absence of DMPP was spectrophotometer determined and pH-shifts with a scaled litmus paper. In sacrificed flasks at the end of incubation morphological changes of the bacteria involved were studied by transmission electron microscope (TEM). Results The ammonium, nitrite and nitrate determinations and the TEM pictures show that in presence of the field applied DMPP concentration the nitrifying activity returned around 30 days later than in the control and the cells were slightly enlarged. In presence of a 10 times higher DMPP concentration a recovery was prevented. DMPP prolongs, compared with dicyandiamide (DCD), the period of nitrifiers’ inhibition and reduced N 2 O− and CO 2 − the emissions (Weiske et al., Biol Fertil Soils 34:109–117, 2001a , Nutr Cycl Agroecosys 60:57–64, b ). Conclusions With the method developed by us the stability of DMPP in agricultural soils can be satisfyingly and reproducible studied down to a detection limit of 0.01 μg DMPP g −1 dry soil. The morphological changes in the nitrifying consortium due to DMPP concentrations are in agreement with the recovery rate found by nitrite and nitrate formation.

Description: Characteristics of metal–oxide–high- k –oxide–silicon (MOHOS) memories with oxygen-rich or oxygen-deficient GdO as charge storage layer annealed by NH 3 or N 2 are investigated. Transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction are used to analyze the cross-sectional quality, composition and crystallinity, respectively, of the stacked gate dielectric with a structure of Al/Al 2 O 3 /GdO/SiO 2 /Si. The MOHOS capacitor with oxygen-rich GdO annealed in NH 3 exhibits a good trade-off among its memory properties: large memory window (4.8 V at ±12 V, 1 s), high programming speed (2.6 V at ±12 V/100 μs), good endurance and retention properties (window degradation of 5 % after 10 5 program/erase cycles and charge loss of 18.6 % at 85 °C after 10 years, respectively) due to passivation of oxygen vacancies, generation of deep-level traps in the grain boundaries of the GdO layer and suppression of the interlayer between GdO and SiO 2 by the NH 3 annealing.

Description: Background and aims Adequate zinc (Zn) in maize ( Zea mays L.) is required for obtaining Zn-enriched grain and optimum yield. This study investigated the impact of varying Zn fertilizer placements on Zn accumulation in maize plant. Methods Two pot experiments with same design were conducted to investigate the effect of soil Zn heterogeneity by mixing ZnSO 4 ·7H 2 O (10 mg Zn kg −1 soil on an average) in 10–15, 0–15, 25–30, 0–30, 30–60 and 0–60 cm soil layers on maize root growth and shoot Zn content at flowering stage in experiment-1, and assessing effects on grain Zn accumulation at mature stage in experiment-2. Results In experiment-1, Zn placements created a large variation in soil DTPA-Zn concentration (0.3–29.0 mg kg −1 ), which induced a systemic and positive response of root growth within soil layers of 0–30 cm; and shoot Zn content was increased by 102 %–305 % depending on Zn placements. Supply capacity of Zn in soil, defined as sum of product of soil DTPA-Zn concentration and root surface area at different soil layers, was most related to shoot Zn content ( r  = 0.82, P  〈 0.001) via direct and indirect effects according to path analysis. In experiment-2, Zn placements increased grain Zn concentration by up to 51 %, but significantly reduced the grain Zn harvest index from 50 % by control to about 30 % in average. Conclusion Matching the distribution of soil applied Zn with root by Zn placement was helpful to maximize shoot Zn content and grain Zn concentration in maize.

Description: Background and Aims Wetting-drying cycles are important environmental processes known to enhance aggregation. However, very little attention has been given to drying as a process that transports mucilage to inter-particle contacts where it is deposited and serves as binding glue. The objective of this study was to formulate and test conceptual and mathematical models that describe the role of drying in soil aggregation through transportation and deposition of binding agents. Methods We used an ESEM to visualize aggregate formation of pair of glass beads. To test our model, we subjected three different sizes of sand to multiple wetting-drying cycles of PGA solution as a mimic of root exudates to form artificial aggregates. Water stable aggregate was determined using wet sieving apparatus. Results A model to predict aggregate stability in presence of organic matter was developed, where aggregate stability depends on soil texture as well as the strength, density and mass fraction of organic matter, which was confirmed experimentally. The ESEM images emphasize the role of wetting-drying cycles on soil aggregate formation. Conclusions Our experimental results confirmed the mathematical model predictions as well as the ESEM images on the role of drying in soil aggregation as an agent for transport and deposition of binding agents.

Description: Background and aims Many plant growth-promoting endophytes (PGPE) possessing 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity can reduce the level of stress ethylene and assist their host plants cope with various biotic and abiotic stresses. However, information about the endophytic bacteria colonizing in the coastal halophytes is still very scarce. This study aims at isolating efficient ACC deaminase-producing plant growth-promoting (PGP) bacterial strains from the inner tissues of a traditional Chinese folk medicine Limonium sinense (Girard) Kuntze, a halophyte which has high economic and medicinal values grown in the coastal saline soils. Their PGP activity and effects on host seed germination and seedling growth under salinity stress were also evaluated. Methods A total of 126 isolates were obtained from the surface sterilized roots, stems and leaves of L. sinense (Girard) Kuntze. They were initially selected for their ability to produce ACC deaminase as well as other PGP properties such as production of indole-3-acetic acid (IAA), N 2 -fixation, and phosphate-solubilizing activities and subsequently identified by the 16S rRNA gene sequencing. For selected strains, seed germination, seedling growth, and flavonoids production in axenically growth L. sinense (Girard) Kuntze seedlings at different NaCl concentrations (0–500 mM) were quantified. Results Thirteen isolates possessing ACC deaminase activity were obtained. The 16S rRNA gene sequencing analysis showed them to belong to eight genera: Bacillus , Pseudomonas , Klebsiella , Serratia , Arthrobacter , Streptomyces , Isoptericola , and Microbacterium . Inoculation with four of the selected ACC deaminase-producing strains not only stimulated the growth of the host plant but also influenced the flavonoids accumulation. All four strains could colonize and can be re-isolated from the host plant interior tissues. Conclusions These results demonstrate that ACC deaminase-producing habitat-adapted symbiotic bacteria isolated from halophyte could enhance plant growth under saline stress conditions and the PGPE strains could be appropriate as bioinoculants to enhance soil fertility and protect the plants against salt stress.

Description: Tin targets immersed in ethanol and distilled water were ablated using a UV pulsed laser. The ablated products were investigated with transmission and scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive spectroscopy. For ablation in both liquids, the size distribution of the produced particles was bimodal, with particles having diameters of ∼10 nm and ∼1 μm. Formation mechanisms that caused the bimodal distribution are suggested. Ablation in ethanol resulted in nanoparticles that were found to be single crystals of tin coated with tin hydroxide (Sn(OH) 2 ) while ablation in water yielded nanoparticles that were polycrystalline tin dioxide (SnO 2 ) throughout.

Description: Thin aluminum oxide layers deposited on silicon by thermal atomic layer deposition can be used to reduce the electronic recombination losses by passivating the silicon surfaces. To activate the full passivation ability of such layers, a post-deposition annealing step at moderate temperatures (≈400  ∘ C, duration≈30 min) is required. Such an annealing step is commonly done in an oven in air, nitrogen, or forming gas atmosphere. In this work, we investigate the ability to reduce the duration of the annealing step by heating the silicon wafer with a microwave source. The annealing time is significantly reduced to durations below 1 min while achieving effective minority carrier lifetimes similar or higher to that of conventionally oven-annealed samples.

Description: A theoretical study is presented on the on/off current ratio limits for a ballistic coaxially-gated carbon nanotube field effect transistor (CNTFET) with highly doped source/drain regions. Based on changes in gate insulator dielectric constant and thickness, the current ratio has been estimated at different ambient temperatures. Decreasing the gate insulator thickness after a certain value around 3 nm causes the current ratio to degrade drastically. Although the higher dielectric constant values have a fair effect on current ratio, this effect could be suppressed when the device with a low gate insulator thickness works at a low ambient temperature. The simulation results also show that the temperature drastically degrades the current ratio value; whereas in a certain range of ambient temperature, tuning the values of gate insulator thickness and dielectric constant could be very helpful. In this way, the optimum values of gate insulator thickness and dielectric constant are identified to offer the highest on/off current ratio of the device.

Description: Pyramid-like spikes in a single crystal superalloy were investigated upon irradiation with picosecond (ps) laser pulses (200 ps, 800 nm, 1 kHz) under different laser fluences and pulse numbers. Both sides and grooves of pyramid-like spikes were covered with ripples, which had a period of ∼760 nm. The pyramid-like spike separation increased obviously with increasing laser fluence. Microstructural investigations indicate that the pyramid-like spikes were initiated with subsequent pulses from a smooth surface with corrugations and ripples. The coexistence of capillary waves for spikes and capillary waves for ripples in the melted material can be used to explain the formation of the pyramid-like spikes.

Description: This paper is to explore the effects of the liquid structure transition (LST) on the solidification kinetics of Sn-30 wt% Sb alloy by the Newton thermal analysis (NTA) method and the solidified microstructure analysis. Influence of the cooling rate on solidification behavior and microstructure was also concerned. With a self-designed sand mold, the cooling curves of five points were collected automatically in the process of solidification by a HYDRA. In the case of the liquid structure transition and a faster cooling rate, the modification melt treatment will lead to a higher undercooling of nucleation and an increased solidification latent heat in central part of solidifying castings, then the eventual grain size was evidently refined.

Description: Aims The objective of this study was to investigate the effects of future warming and drought on (1) the biochemical composition of above-ground biomass of forage plants ( Festuca arundinacea and Dactylis glomerata ), (2) the potential mineralization of this material in soil, and (3) its priming effect on native soil organic matter. Methods We sampled above-ground plant material from spring regrowth and summer regrowth of a climate change experiment. While in spring, the plants were well watered, the summer regrowth was exposed to drought and elevated temperature (+3 °C) by infrared heating of the canopy during 3 weeks. We assessed the elemental and isotopic composition, lignin and non-cellulosic carbohydrate content and composition of plant material grown under all three conditions. Its mineralization potential in soil and priming effects were evaluated during laboratory incubation. Results Warming had no significant effect on elemental and stable isotope composition of both plant materials. In contrast, it resulted in reduction of lignin content for both plant species and decrease of the lignin-to-N ratio for F. arundinacea and increased non-cellulosic carbohydrate content for D. glomerata . Summer regrowth was characterised by increase of δ 13 C values, which is consistent with variations in stomatal conductance due to water shortage. Moreover, summer drought induced an increase in N content leading to decrease of the C/N ratio and increase of lignin-to-N ratio of summer regrowth compared to spring regrowth. Differences in decomposition were small, while priming effects were more strongly altered by the different exposure to enviromental. Conclusion Our results provide direct experimental evidence that extreme climatic events (high temperature and precipitation deficit) have an influence on soil carbon storage particularly through their effect on priming of native soil organic matter induced by altered plant litter. These effects seem to be governed by alterations of stoichiometry and to a smaller extent by alterations of plant chemical composition.

Description: In the paper we report on picosecond-laser bulk microstructuring and stimulated Raman scattering (SRS) in type IIa single-crystal diamond in the course of multipulse irradiation at λ =532 nm wavelength using an advanced ps-laser system equipped with additional setups for on-line video imaging and photoluminescence spectra measurements. The effect of crystal orientation (relative to the incident laser beam) on (i) optical breakdown thresholds, (ii) character of bulk modifications, and (iii) generation of stimulated Raman scattering in diamond during irradiation with picosecond pulses of different durations ( τ 1 =10 ps and τ 2 =44 ps) is studied. It is shown that the processes of laser-induced breakdown in the bulk of diamond (at the backside of the crystals) and bulk microstructure growth are governed by the dielectric breakdown mechanism. It is found that generation of high-order stimulated Raman scattering in diamond crystals has a considerable effect on the threshold of laser-induced breakdown and bulk microstructuring. Conditions of the efficient SRS lasing are determined, depending on the pulse duration and the direction ([100] and [110]) of the laser beam incidence. A method of local temperature measurements in the bulk of diamond based on the Stokes-to-anti-Stokes intensity ratio in the recorded SRS spectra is proposed, its applicability to determine a “pre-breakdown” temperature of diamond during multipulse ps-laser irradiation is discussed.

Description: Background and aim Saccharothrix algeriensis NRRL B-24137, isolated from a Saharan soil, has been described as a potential biocontrol agent against Botrytis cinerea and other phytopathogens. However, the plant protection mechanisms involved still need to be described. The aim of this study was to determine this protection phenomenon as well as parts of the mechanisms involved, using Arabidopsis thaliana seedlings and B. cinerea . Methods The bacterial colonization process was evaluated on A. thaliana seedlings using fluorescence in situ hybridization. Protection of A. thaliana seedlings inoculated with NRRL B-24137 against B. cinerea was then evaluated. Parts of the mechanisms involved in the systemic protection against B. cinerea were evaluated using known mutants of genes involved in jasmonate (JA)/ethylene (ET)/salicylic acid (SA) signaling. Other Arabidopsis mutants, AtrhbohD-3 , AtrhbohF-3 , and ups1-1 were also screened to determine other parts of the mechanisms involved. Results The results showed that the strain NRRL B-24137 colonized, epi- and endophytically, the roots of Arabidopsis seedlings but the strain was not a systemic colonizer during the time of the experiment. The strain NRRL B-24137 also reduced B. cinerea symptoms and the protection was linked to known mechanisms of induced systemic resistance (ISR; JA/ET signaling), as well as to functionality of AtrbohF oxidase and of UPS1. Crosstalk between ET/JA and SA signaling could also be involved. Conclusions The isolate NRRL B-24137, after colonizing the root systems of A. thaliana , induces an ISR against B. cinerea , which is JA/ET dependent, but could also require SA crosstalk and protection could also require NAPDH oxidases and UPS1 functionalities.

Description: Copper oxide (CuO) is a p-type semiconductor with a band gap of 1.2 eV, which is well known in high-temperature superconductor and antiferromagnetic (AFM) materials through Cu–O–Cu super-exchange interaction. In this paper, we report the strong anisotropic ferromagnetism (FM) in aligned CuO nanorod arrays synthesized by a microwave-assisted hydrothermal method. The transmission electron microscopy (TEM) image shows that the CuO nanorod consists of a large number of smaller nanorods with almost the same growth direction. The X-ray diffraction (XRD) pattern indicates that the CuO nanorods are well crystallized with highly preferred orientation of the [020] direction. These CuO nanorod arrays show room-temperature ferromagnetism, with strong magnetic anisotropy when the magnetic field is applied perpendicular or parallel to the rod axis. This phenomenon of room-temperature ferromagnetism in those aligned CuO nanorods might originate from uncompensated surface spins and shape anisotropy of the nanorods.

Description: (TiVCrZrY)N coatings were deposited onto Si substrate by the radio-frequency (RF) magnetron sputtering of a TiVCrZrY alloy target in an N 2 /Ar atmosphere. The crystal, microstructural, mechanical, and electrical properties at different N 2 -to-total (N 2 +Ar) flow-rate ratio ( R N ) values were investigated. The coating produced in pure Ar had an equiaxed structure with a hexagonal-close-packed phase. With increased R N , the crystallinity and grain size markedly decreased. The microstructure of (TiVCrZrY)N coatings transformed from V-shaped columnar with a rough-domed surface into fine fibrous with a smooth surface. The amorphous transition layer above the substrate was also significantly thickened. The hardness of (TiVCrZrY)N decreased from 20.9 GPa to 18.9 GPa, and the electrical resistivity increased from 398.2 μΩ⋅cm to 21870 μΩ⋅cm.

Description: Background and aims The effect of forest cover distribution and plant litter input on soil organic carbon were analyzed to better understand the dynamics of carbon cycling across ecosystems on the “Natural Oriented Reserve Bosco delle Pianelle”. Fluorescence spectroscopy represents a very useful tool to characterize soil organic matter properties, since it allows to directly monitor the molecular status of a fluorophore depending on its chemical environment, as well as on its structure, substituents of the aromatic moieties, and molecular weight. Here, fluorescence analysis was performed on humic acids isolated from four litters (HALs) and their underlying soils (HAs) at three depths. Methods All samples were collected from a protected forest area, Southern Italy, under different plant covering: Quercus ilex L. (Q), mixed Carpinus betulus L. and Carpinus orientalis Mill. (CC), Pinus halepensis L. (P), and mixed Quercus trojana Webb. and Quercus ilex L. (QQ). Results Data obtained showed a fast decomposition process for P and QQ litters, with HAs in the underlying soils characterized by the presence of simple, highly fluorescent structural components also in the deepest layers. On the contrary, a slow decomposition process was observed for Q and CC litters, whose underlying soil HAs were characterized by an increasing aromatic polycondensation and humification degree from the surface to the deepest layers, as supported by low values of fluorescence intensity and high wavelength maxima. Conclusions Results obtained indicate that P and QQ species promote C accumulation and stock in the underlying soils, thanks to a greater decomposition of their litter, and fluorescence spectroscopy is a very simple and suitable method to evaluate the influence of three species distribution on soil organic carbon pools.

Description: Aims The objective of our study was to confirm if hydraulic lift (HL) promotes nutrient uptake in field-grown plants in the same way as demonstrated previously in pot-grown plants. Methods We conducted a field experiment in an agroforestry system, over an entire growing season that included a dry period and a wet period. We used a shallow-root crop plant, mung bean ( Vigna radiata L.), intercropped with walnut ( Juglans regia L.) and jujube ( Zizyphus jujube Mill.), as an indicator for the presence of HL and its effects on nutrient uptake. To monitor HL, we artificially applied deuterium isotope to the deep roots of trees. Results We demonstrated the presence of a natural nitrogen, phosphorus, and potassium gradient along the soil depth, and the occurrence of HL, evidenced by deuterium signature in the shallow soil layers and V. radiata stem, only during the dry season. J. regia and Z. jujube both had deep root systems, but the former species exhibited stronger HL to the shallow soil than the latter. Meanwhile, the upper soil layers of J. regia had significantly higher moisture content, and the intercropped V. radiata had higher nutrient content. Conclusion HL can facilitate water uptake by V. radiata from the upper soil layers in the field condition during the dry season, which relates to nutrient acquisition by the crop.

Description: The blue InGaN light-emitting diodes (LEDs), employing a lattice-compensated p-AlGaN/InGaN superlattice (SL) interlayer to link the last quantum barrier and electron blocking layer (EBL), are proposed and investigated numerically. The simulation results indicate that the newly designed LEDs have better hole injection efficiency, lower electron leakage, and smaller electrostatic fields in the active region over the conventional LEDs mainly attributed to the mitigated polarization-induced downward band bending. Furthermore, the markedly improved output power and efficiency droop are also suggested when the conventional LEDs corresponding to experiment data are replaced by the newly designed LEDs.

Description: In this paper, we investigate the resonance magnetoelectric (ME) effect in the middle supported multilayer composites consisting of high-permeability Fe-based nanocrystalline soft magnetic alloy Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9 (FeCuNbSiB), Nickel (Ni), and piezoelectric Pb(Zr 1− x Ti x )O 3 (PZT). The coupling effect between positive magnetostrictive FeCuNbSiB and negative magnetostrictive Ni results in the build-in magnetic bias due to their different magnetic permeability and coercivity. As a result, a giant resonance ME voltage coefficient ( α ME, r ) at zero DC magnetic bias field ( H dc ) and multi-peaks of α ME, r for FeCuNbSiB/Ni/PZT/Ni/FeCuNbSiB composite are observed. The experimental results show that the giant zero-biased α ME, r strongly depends on the thickness of FeCuNbSiB ribbon. The maximum zero-biased α ME, r is up to 86 V/cm Oe for FeCuNbSiB/Ni/PZT/Ni/FeCuNbSiB with four-layer FeCuNbSiB ribbons, which is ∼500 times higher than that of the previously reported NKNLS-NZF/Ni/NKNLS-NZF trilayer composite. Compared with the peak α ME, r and the optimum H dc of Ni/PZT/Ni composite, the largest peak α ME, r of FeCuNbSiB/Ni/PZT/Ni/FeCuNbSiB composite with four-layer FeCuNbSiB ribbons increases ∼185 %, and the optimum H dc decreases ∼300 Oe, respectively. Based on the nonlinear magnetostrictive constitutive relation and the magnetoelectric equivalent circuit, a theoretical model of α ME, r versus H dc is built under free boundary conditions. Calculated zero-biased α ME, r and α ME, r versus H dc are in good agreement with the experimental data. This laminate composite shows promising applications for high-sensitivity power-free magnetic field sensors, zero-biased ME transducers and small-size energy harvesters.

Description: In this paper, we report on in-situ atomic force microscopy (AFM) studies of topographical changes in azobenzene-containing photosensitive polymer films that are irradiated with light interference patterns. We have developed an experimental setup consisting of an AFM combined with two-beam interferometry that permits us to switch between different polarization states of the two interfering beams while scanning the illuminated area of the polymer film, acquiring corresponding changes in topography in-situ . This way, we are able to analyze how the change in topography is related to the variation of the electrical field vector within the interference pattern. It is for the first time that with a rather simple experimental approach a rigorous assignment can be achieved. By performing in-situ measurements we found that for a certain polarization combination of two interfering beams [namely for the SP (↕, ↔) polarization pattern] the topography forms surface relief grating with only half the period of the interference patterns. Exploiting this phenomenon we are able to fabricate surface relief structures with characteristic features measuring only 140 nm, by using far field optics with a wavelength of 491 nm. We believe that this relatively simple method could be extremely valuable to, for instance, produce structural features below the diffraction limit at high-throughput, and this could significantly contribute to the search of new fabrication strategies in electronics and photonics industry.

Description: Traditional glass micromachining using laser processing in air would produce many kinds of defects, such as bulges, debris, micro-cracks and scorches. In this article, a poly-dimethylsiloxane (PDMS) protection processing has been presented to reduce the temperature gradient and heat-affected zone (HAZ) to achieve crack-free Pyrex glass machining. A good quality of etched surface which is a clear and much-reduced bulge without crack and scorch is achieved using CO 2 laser micromachining at 150 μm thick PDMS protection layer and the laser powers of 10–15 W and scanning speeds of 228–342 mm/s for five passes. The PDMS cover layer benefits feature size and bulge height reduction. The alpha-step measured profile shows that the much reduced bulge height around the rims of channel was about 1.2 μm at 150 μm thick PDMS about 13 times smaller than that in air. The ANSYS software was used to analyze the temperature distribution and thermal stress field of glass micromachining in air without and with PDMS cover layer. The smaller temperature gradient observed in PDMS protection processing has the smaller HAZ and diminishes the crack formation during the laser processing.

Description: To reduce the cost of the emitter diffusion process, there has been increasing interest to substitute the standard process of batch POCl 3 emitter diffusion used in the silicon solar-cell manufacturing industry with in-line diffusion processes such as the spray-on and screen-printing process. For this reason, it is essential to study and compare the processes of different diffusion methods from the point of view of the crystalline quality of the final wafers. X-ray transmission topography was employed to characterize the possible precipitates and other microdefects generated in Czochralski-grown silicon (Cz Si) during the emitter diffusion process carried out by screen-printing, spray-on and the standard process, in which the emitter was provided by a liquid (POCl 3 ) source. The results indicate that the phosphorus diffusion process influences the crystalline quality of the wafers and the efficiency of the external gettering process that takes place during phosphorus diffusion depends on the diffusion method employed.

Description: We propose the use of a La 2 O 3 (LO) film as the capping layer for improvement of a semiconductor/insulator interface in a solution-processed indium–tin–oxide (ITO) ferroelectric-gate thin-film transistor (FGT) device. It is demonstrated that the LO layer acts as a good barrier film not only for preventing the interdiffusion between the ITO semiconductor and lead–zirconium-titanate (PZT) insulator layers, but also for stabilizing the PZT surface structure. The fabricated FGT device exhibited high I on / I off , large M w , high μ FE and improved retention time of about 10 9 , 3.5 V, 7.94 cm 2  V −1  s −1 and 1 day, respectively, which are comparable to or better than those obtained with FGTs fabricated by means of conventional vacuum processes. We also point out that the key origin of the interface improvement is likely due to the incorporation of La into the PZT system, forming a La surface-modified PZT system which is more stable than the pure PZT in terms of Pb volatility and formation of oxygen vacancies.

Description: The results of ferroelectric properties studies of KNN doped with La and Ti and sintered at temperatures in the interval of 1100 °C–1190 °C are presented in this work. The doping was achieved by the substitution of La for ions in A sites and Ti for ions in the B sites. Values of 94 % of the theoretical density were accomplished. The effect of the sintering temperature and the inclusion of the La and Ti cations in the KNN structure is evident through the shift in the ferroelectric-paraelectric transition temperature of ∼110 °C with respect to that of pure KNN (420 °C). Microstructure and ferroelectric analyses were carried out using Piezoresponse Force Microscopy (PFM) and hysteresis loops with interesting results, Δ P r =9 (μC/cm 2 ) and P r / P max =0.41, even when the saturation of the materials is not reached.

Description: We have developed a high-performance laser energy meter based on anisotropic Seebeck effect in a strongly correlated electronic (SCE) thin film. SCE thin films, typically represented by high-temperature superconductor (HTS) cuprate and colossal magnetoresistance (CMR) manganite thin films, demonstrate tremendous anisotropic Seebeck effect. In this study, a La 2/3 Ca 1/3 MnO 3 thin film grown on a tilted LaAlO 3 substrate is tested with the fundamental, the second, the third, and the fourth harmonics (1064, 532, 355, 266 nm, respectively) of a Q-switched Nd:YAG laser over a wide range of temperatures from room temperature to 16 K. The peak-value of the laser-induced thermoelectric voltage signal shows a good linear relationship with the laser energy per pulse in the measured wavelength and temperature ranges. The combined advantages over other commercial laser detectors such as nanosecond-order response and spectrally broad and flat response over a wide range of temperatures, in situ real-time measurement, and energy savings, make the device an ideal candidate for next-generation laser detectors and laser power/energy meters.

Description: Co-doped ZnO epilayer films were grown by pulsed laser deposition (PLD) on vicinal cut silicon and sapphire substrates. Changes in deposition time were observed as a moderate effect on the quality of the films, and the influence of the thickness on thermoelectric signals from Zn 0.9 Co 0.1 O thin films were discussed. The effect of one of the main deposition parameters, the deposition time, on the crystallinity and electron mobility properties of the Zn 0.9 Co 0.1 O thin films grown on sapphire was investigated by means of X-ray diffraction (XRD) and laser-induced voltage (LIV) effect. It shown that the XRD rocking curve full-width half-maximun (FWHM) decreased as time increasing, and the LIV signals were observed along the tilting angle of the substrate orientation when the pulsed KrF excimer laser of 248 nm were irradiated on the films. When the films illuminated in pulse lasers, the highest signals occurred in the films with best crystalline quality, and the signals were higher in the films grown on sapphire than those on silicon substrates. It suggested that the electrical resistivity and electron mobility have close relations with not only the crystallinity but also with the interface of the thin films.

Description: Nanostructure formation on bulk noble metals (copper, gold and silver) by a femtosecond laser was studied aiming at the production of low-reflectivity surfaces. The target surface was irradiated with the beam of a 775 nm wavelength and 150 fs pulse duration Ti:sapphire laser. The fluence was in the 16–2000 mJ/cm 2 range, while the average pulse number was varied between 10 and 1000 depending on the scanning speed of the sample stage. The reflectivity of the treated surfaces was measured with a visible–near-infrared microspectrometer in the 450–800 nm range, while the morphology was studied with a scanning electron microscope. A strong correlation was found between the decreasing reflectivity and the nanostructure formation on the irradiated surface; however, the morphology of silver significantly differed from those of copper and gold. For the two latter metals a dense coral-like structure was found probably as a result of cluster condensation in the ablation plume followed by diffusion-limited aggregation. In the case of silver the surface was covered by nanodroplets, which formation was probably influenced by the ‘spitting’ caused by ambient oxygen absorption in the molten silver followed by its fast release during the resolidification.

Description: The automation in fabrication of CFRP (carbon-fiber-reinforced plastics) parts demands efficient and low-cost machining technologies. In conventional cutting technologies, tool-wear and low process speeds are some of the reasons for high costs. Thus, the use of lasers is an attractive option for cutting CF-preforms. A typical effect degrading the quality in laser cutting CF-preform is a bulged cutting edge. This effect is assumed to be caused by interaction of the fibers with the ablated material, which leaves the kerf at high velocity. Hence, a method for measuring the momentum and the velocity of the vapor is presented in this article. To measure the momentum of the ablated material, the CF-preform is mounted on a precision scale while cutting it with a laser. The direction of the momentum was determined by measuring the momentum parallel and orthogonal to the CF-preform surface. A change of the direction of the momentum with different cutting-speeds is assessed at constant laser-power. Averaged velocities of the ablation products of up to 300 m/s were determined by measuring the ablated mass and the momentum.

Description: Aims and background Despite increasing knowledge of the role of allelochemicals in the productivity decline of replanted Chinese fir plantations, relatively little is known about the levels and sources of allelochemicals in relation to autoinhibition. Methods Allelopathic potential of litter, root exudates, and soils in successive rotations of Chinese fir plantations were detected. An allelochemical cyclic dipeptide (6-hydroxy-1,3-dimethyl-8-nonadecyl-[1,4]-diazocane-2,5-dione) from litter, root exudates, and soils in successive rotations was quantified. Results Extracts of leaf litter, fine root, and root exudates significantly inhibited the growth of Chinese fir germinants, and inhibition increased with successive rotations. Similar results were observed in the rhizosphere soil, basal soil, and bulk soil. The largest observed inhibition occurred in the rhizosphere soil. Furthermore, cyclic dipeptide was found in litter, root exudates, and soils, and the concentrations increased with successive rotations. The rhizosphere soil had the highest cyclic dipeptide level, followed by basal soil, while bulk soil contained the lowest concentration. There was a significant positive relationship between the inhibition of radicle growth of Chinese fir germinants and the concentration of cyclic dipeptide. Annual release of cyclic dipeptide through root exudation was 2.08–9.78 mol ha −1 annum, but the annual release of cyclic dipeptide through leaf litter decomposition was lowered to 0.32–1.41 mol ha −1 annum. Conclusions Cyclic dipeptide which caused autoinhibition of Chinese fir may be released into the soil through litter decomposition and root exudation. Root exudates provided more contributions to soil cyclic dipeptide levels than litter in Chinese fir plantations.

Description: Background and aims In the Central Negev hills (Israel) many ancient terraced wadis exist, which captured run-off and caused gradual soil aggradation, which enabled agricultural practices. In these terraces, dark colored soil horizons were observed, containing charcoal, as can be found in Terra Preta soils, suggesting higher fertility compared to natural soils. The aim of our investigation was to investigate these anthropogenic soils and to study the effects of charcoal and ash addition on soil properties and crop growth. Methods We investigated 12 soil profiles, focusing on possible differences between light and dark colored soil horizons. We also investigated the effects of amendment of charcoal and ash on the growth of wheat ( Triticum Aestivum L. ) in a 40-day pot experiment involving two water regimes. Results Results show that charcoal content in light and dark horizons were both low (〈0.2 %), but significantly lower bulk densities were found in dark colored horizons. In the crop experiment, charcoal addition resulted in decreased crop growth, while, in the water deficit regime, ash addition resulted in increased crop growth. Conclusions Considering the observed charcoal and the results from the crop experiment, we hypothesize that, in ancient run-off capturing agricultural systems, ash was purposefully added as fertilizer.

Description: Introduction In a recent paper, Warren et al. ( 2013 ) illustrated the potential of neutron radiography to visualize water dynamics in soil and plants. Methods After injection of deuterated water (D 2 O) in soil, the authors could monitor the changes of D 2 O concentration in roots. Results Based on the radiographs, the authors concluded that D 2 O was transported from roots growing in a wet soil region to roots in a dry region, proving hydraulic redistribution between roots. However, this interpretation depends on the correct estimation of D 2 O concentration in soil. Conclusions The experiments of Warren et al. ( 2013 ) could also be explained by diffusion of D 2 O from soil to roots, without hydraulic redistribution within the root system.

Description: Aims The mechanisms of belowground competition are not well understood. Addressing literature reports on competition-induced changes in tree fine root morphology, we conducted a growth experiment with tree saplings to investigate competition effects on important root morphological and functional traits in a root order-focused analysis. Methods European beech and European ash saplings were grown for 34 months in containers under greenhouse conditions in monoculture (2 conspecific plants), in mixture (1 beech and 1 ash) or as single plants. The root system was fractionated according to root orders and eight morphological and functional properties were determined. Results Root order was the most influential factor affecting the fine root traits (except for root diameter and δ 13 C); a significant species identity effect was found for root diameter, tissue density, N concentration and δ 13 C. Ash fine roots were thicker, but had lower tissue densities, contained more N and had systematically higher δ 13 C values than beech roots. The competition treatments had no significant effect on morphological root traits but altered δ 13 C in the 2nd root order. Conclusion Neither intra- nor interspecific root competition affected fine root morphology significantly suggesting that competition-induced root modification may not be a universal phenomenon in temperate trees.

Description: We report a design method of surface plasmon polaritons sharp bends based on transformation optics. Plasmonic waveguide bends with different angles, which possess little radiation loss, are proposed. Transformation media can be simply achieved with homogeneous and nonmagnetic materials, which can be constructed by altering two different dielectric films. Electromagnetic simulations by a finite-element method on detailed examples have been performed to validate the designs.

Description: This article presents the results on the growth and characterization of BaSnF 4 thin films on glass substrates prepared by pulsed laser deposition technique. The structural results of BaSnF 4 thin film carried out by glancing angle X-ray diffraction technique indicates the formation of the film with similar structure (tetragonal, P 4 /nmm) to the bulk target material. The absorption coefficient and band gap of the film is determined by suitable analysis of the transmittance spectra. The transport properties of the thin films are studied using impedance spectroscopy in the temperature range of 323–573 K. The frequency-dependent imaginary part of impedance plot shows that the conductivity relaxation is non-Debye in nature. The scaling behavior of the imaginary part of impedance at various frequencies indicates temperature-independent relaxation behavior.

Description: UV irradiation of materials consisting of a polymer matrix that possesses precursors of noble metals followed by annealing results in creation of metal nanoparticles within the irradiated domains. Such photoinduced nanocomposites are promising for photonics applications due to the strong alteration of their optical properties compared to initial nonirradiated materials. We report our results on the synthesis and investigation of two kinds of these materials: Photoinduced Au nanocomposites based on PMMA matrices, including bulk materials prepared by means of the polymerization technique; photoinduced Ag nanocomposites with an organic–inorganic hybrid matrix based on TiO 2 gels. The experimental data on evolution of absorption spectra of these materials due to laser irradiation at different wavelengths are presented. The linear and nonlinear refractive index changes in these materials owing to light-induced nanonstructuring are investigated.

Description: The study of pollution performance on a wind turbine blade due to lightning is important, as it can cause major damage to wind turbine blades. In the present work, optical emission spectroscopy (OES) technique is used to understand the influence of pollutant deposited on a wind turbine blade in an off-shore environment. A methodical experimental study was carried out by adopting IEC 60507 standards, and it was observed that the lightning discharge propagates at the interface between the pollutant and the glass fiber reinforced plastic (Material used in manufacturing of wind turbine blades). In addition, as a diagnostic condition monitoring technique, laser-induced breakdown spectroscopy (LIBS) is proposed and demonstrated to rank the severity of pollutant on the wind turbine blades from a remote area. Optical emission spectra observed during surface discharge process induced by lightning impulse voltage is in agreement with the spectra observed during LIBS.

Description: We developed a method that accurately determines an unknown position of the high-intensity laser-pulse-material interaction site on the front side of a plate. It is based on interferometric measurements of a normal displacement at known positions on the plate’s rear side. The displacement is caused by reflections of various pulsed-laser-induced mechanical waves. We have superseded the long-established time-of-flight approach with the improved, triple-echo method. To accurately locate the origin of the laser-induced ultrasound on the plate with a known thickness, we only need to detect the arrivals of the first three consecutive mode unconverted waves. Our method works without knowing the propagation velocities of various ultrasonic waves and additionally solves some time-related drawbacks of the conventional time-of-flight approach. The relative uncertainty of the measured source-receiver separations obtained with the presented method is less than 0.01.

Description: Laser dry etching by a laser driven direct writing apparatus has been extensively used for the micro- and nano-patterning on the solid surface. The purpose of this study is to pattern the PEDOT:PSS thin film coated on the soda-lime glass substrates by a nano-second pulsed ultraviolet laser processing system. The patterned PEDOT:PSS film structure provides the electrical isolation and prevents the electrical contact from each region for capacitive touch screens. The surface morphology, geometric dimension, and edge quality of ablated area after the variety of laser patternings were measured by a 3D confocal laser scanning microscope. After the single pulse laser irradiation, the ablation threshold of the PEDOT:PSS film conducted by the nano-second pulsed UV laser was determined to be 0.135±0.003 J/cm 2 . The single pulse laser interacted region and the ablated line depth increased with increasing the laser fluence. Moreover, the inner line width of ablated PEDOT:PSS films along the patterned line path increased with increasing the laser fluence but the shoulder width increased with decreasing fluence, respectively. The clean, smooth, and straight ablated edges were accomplished after the electrode patterning with the laser fluence of 1.7 J/cm 2 and 90 % overlapping rate.

Description: Selectiveness of the laser processing is the top-most important for applications of the processing technology in thin-film electronics, including photovoltaics. Coupling of laser energy in multilayered thin-film structures, depending on photo-physical properties of the layers and laser wavelength was investigated experimentally and theoretically. Energy coupling within thin films highly depends on the film structure. The finite element and two-temperature models were applied to simulate the energy and temperature distributions inside the stack of different layers of a thin-film solar cell during a picosecond laser irradiation. Reaction of the films to the laser irradiation was conditioned by optical properties of the layers at the wavelength of laser radiation. Simulation results are consistent with the experimental data achieved in laser scribing of copper-indium-gallium diselenide (CIGS) solar cells on a flexible polymer substrate using picosecond-pulsed lasers. Selection of the right laser wavelength (1064 nm or 1572 nm) enabled keeping the energy coupling in a well-defined volume at the interlayer interface. High absorption at inner interface of the layers triggered localized temperature increase. Transient stress caused by the rapid temperature rise facilitating peeling of the films rather than evaporation. Ultra-short pulses ensured high energy input rate into absorbing material permitting peeling of the layers with no influence on the remaining material.

Description: Background and aims Distinct metal distribution patterns within leaves of metal hyperaccumulating plants are repeatedly observed however, the presumable role of key structural biochemical molecules in determining and regulating their allocation remains largely unknown. We aimed to characterise in a spatially resolved manner the distribution of the main biochemical components in leaves of field-collected Cd/Zn-hyperaccumulating Noccaea praecox in order to relate them to metal distribution patterns at tissue level. Methods The biomolecular composition of the leaves was spatially analysed using synchrotron radiation Fourier Transform Infrared (FTIR) and the distribution of Zn with synchrotron radiation Low-Energy X-Ray Fluorescence (LEXRF) microspectroscopy was determined on the same tissues of interest (epidermis, sub-epidermis, mesophyll). Results In epidermal cells high proportion of free-carboxyl, nitro and phosphate groups standing for pectin, nitroaromatics, phytic and other organic acids were found. Adjacent mesophyll cells had higher proportions of proteins, carbohydrates and cellulosic compounds. Conclusions Pectin compounds were indicated as important components of Zn enriched epidermal cell walls. In addition, intense lignification of epidermal cell walls might limit leakage of the trapped metals back to the metabolically active and thus more sensitive mesophyll. Distribution of metal-binding compounds in particular cell types/tissues may therefore predispose metal distribution patterns and tolerance in leaves.

Description: Aims Tree species affect herb layer species through their effects on soil quality and light regime but their relative importance and interactions are insufficiently known. Methods Pot experiment with soil taken from stands planted with tree species with contrasting effects on soil acidification, two light regimes and six forest perennials. Results The survival or growth of Mercurialis perennis, Lamium galeobdolon , Anemone nemorosa and Primula elatior was lower in the acid Alnus soils than in the less acid Fraxinus soils. By contrast, the acid tolerant Convallaria majalis and Dryopteris dilatata were barely affected by tree species. Light conditions had less impact than soil chemistry and did not compensate for unfavourable soil conditions. Ca and P concentrations increased in plants grown in Fraxinus soils. The Mg and Al shoot/root ratios of respectively one and two of the acid tolerant species was elevated in the most acid soil. Conclusions Tree species effects on forest perennials are mainly explained by increased Al concentrations under acidifying species. Changed plant concentrations and allocation are likely associated to Al antagonism. We found no light compensation for the soil effect on the studied species. However, light alters the plant nutrient concentrations and allocation which may suggest an indirect effect.

Description: An integrated microchemical–petrographic approach is here proposed to discriminate the provenance of archaeological pottery artefacts from distinct production centres. Our study focuses on a statistically significant sampling ( n =186) of volcanic temper-bearing potteries representative of the manufacturing and dispersion among the islands of the Aeolian Archipelago during the Bronze Age. The widespread establishment of new settlements and the abundant recovery of Aeolian-made ceramic in southern Italy attest for the increased vitality of the Archipelago during the Capo Graziano culture (Early Bronze Age–Middle Bronze Age 2; 2300–1430 BC). Potteries from three of the main known ancient communities (Lipari, Filicudi and Stromboli) have been studied integrating old collections and newly excavated material. Volcanic tempers have been first investigated through multivariate analyses of relative abundances of mineral and rock clasts along with petrographic characters. In addition, we performed in-situ mineral chemistry microanalyses by Electron Microprobe and Laser Ablation—Inductively Coupled Plasma Mass Spectrometry to assess major and trace element composition of the most common mineral phases. Four Temper Compositional Reference Units have been recognised based on compositional trends. Two units (AI and AX) are unequivocally distinct by their peculiar trace element enrichment and petrographic composition; they mostly contain samples from the sites of Lipari and Stromboli, respectively. Units AIV and AVIII, restricted to the sites of Filicudi and Stromboli, show distinct petrographic characters but overlapped geochemical fingerprints.

Description: Dissemination of Della Robbia glazed terracotta in the Marche (Italy) region started from the third decade of the 16th century. Numerous altarpieces, some of which no longer exist, document this artistic production. The protagonists of this diffusion phase were two of Andrea Della Robbia’s sons, Marco (Fra Mattia) and Francesco (Fra Ambrogio). This paper shows the results of the scientific investigations carried out on constitutive materials of different altarpieces located in South Marche belonging to the Fra Mattia’s production: the Coronation of Virgin between Saints Rocco, Sebastian, Peter martyr and Antonio abbot , dated back to 1527–1530, located in the collegiate church of S. Maria Assunta in Montecassiano; the Annunciation , dated back to 1520, placed in the church of S. Maria del Soccorso in Arcevia; the fragmentary Crowned Madonna and saints altarpiece, probably realized after 1531, today preserved in Civic Museum of Ripatransone. The first altarpiece was made in Montecassiano using two different assembling or production techniques: the external part of the lunette and the pillar strips are made of glazed polychrome terracotta, while the altar step and the internal part are an interesting and uncommon example of polychrome painted terracotta. The provenance of the glazed Arcevia altarpiece is not clear yet: some historians hypothesize a local manufacture of Fra Mattia and some others a Roman or Florentine production. The remaining parts of Ripatransone altarpiece are partially glazed and partially not coated perhaps because they were unfinished and not yet painted. Clay body samples collected from the above mentioned altarpieces were investigated using different analytical techniques (OM, XRD, XRF, PIXE) to point out differences in chemical and mineralogical composition and to determine if the altarpieces were made by using local raw clay materials or other clays from Tuscany or Campania as in the Della Robbia previous production. A comparison has also been made with literature data on the Della Robbia terracotta masterpieces. From the chemical point of view, the clay bodies show a good compositional homogeneity and result calcium and iron-rich according with the raw local materials. The presence of gehlenite, pyroxenes, and hematite and the incomplete decomposition of clay minerals indicate that firing for all different terracotta parts occurred in a thermal range between 800 and 950 °C, mostly in oxidizing conditions.

Description: Aims The aim of this study was to determine whether goat grazing in the understory of a pine forest at Doñana Natural Park could accelerate the decomposition of the pine needles accumulated on the soil surface and, if so, through which mechanisms. Specifically, the roles of trampling (mechanical fragmentation) and nutrient enrichment through defecation (fertilization) were evaluated in terms of their effect on pine needle decomposition rates. Methods An experiment was conducted featuring the following 4 treatments: 1) intact needles (control), 2) trampled needles, 3) intact needles fertilized with liquid manure, and 4) trampled needles fertilized with liquid manure. Litter decomposition was determined as a function of mass loss over time, using the litter-bag method. Bags were recovered 4, 8, 16, 24 and 36 months after burial in soil, dried and weighed. Needle length, leaf mass per area and C and N concentration were also measured in the buried litter-bags. Results Four months after burial, mass loss was greater in the trampled (23–27 %) than non-trampled (14–16 %) treatments. However, from 8 months onwards, decomposition rates in the fertilized treatments were significantly higher than those in the non-fertilized treatments (between 5 % and 15 % less mass loss). Meanwhile, fertilized treatments presented higher N content (2.1 %) than the non-fertilized ones (1.2 %), with a significantly lower C:N ratio also found in the in the fertilized treatment. Conclusions Trampling and fertilization during grazing accelerates litter decomposition and thus promotes the incorporation of N into the system. Acceleration of decomposition reduces the accumulation of pine needles on the soil surface, reducing the risk of fire.

Description: Optical and biomedical properties of diamond-like carbon (DLC) films of various sp 2 , sp 3 bonds were studied. The layers were prepared by pulsed laser deposition (PLD) for laser energy densities from 4 J cm −2 to 14 J cm −2 . The percentage of sp 2 and sp 3 bonds was calculated using X-ray photoelectron spectroscopy (XPS). In dependence on density the films contained up to 70 % of sp 3 bonds. Optical properties were measured using spectroscopic ellipsometry in region from 250 nm to 1000 nm ( n =2.6–2.7; k =0.07–0.25) and by transmission measurement (from 200 nm to 1100 nm). The adhesion and growth of human fibroblasts and keratinocytes of DLC films were tested in vitro.

Description: Bubbles generated in water by focusing femtosecond and picosecond laser pulses in the presence of 100 nm gold nanoparticles have been investigated in the fluence range usually used for efficient cell transfection (100–200 mJ/cm 2 ). Since resulting bubbles are at the nanoscale, direct observation using optical microscopy is not possible. An optical in-situ method has been developed to monitor the time-resolved variation in the extinction cross-section of an irradiated nanoparticle solution sample. This method is used to measure the bubbles lifetime and deduce their average diameter. We show that bubbles generated with femtosecond pulses (40–500 fs) last two times longer and are larger in average than those generated with picosecond pulses (0.5–5 ps). Controlling those bubble properties is necessary for optimizing off-resonance plasmonic enhanced ultrafast laser cell transfection.

Description: To determine experimental conditions suitable for isotope analysis, we studied the plume dynamics of uranium. A uranium oxide sample was ablated by 2nd harmonic radiation from a Nd:YAG laser at a fluence of 0.5 J/cm 2 . The temporal evolution of the ablation plume was investigated in vacuum and helium environments. In vacuum, the flow velocity perpendicular to the sample surface was determined to be 2.7 km/s for neutral atoms and 4.0 km/s for singly charged atoms. These velocities are about 20 % lower than those of cerium measured under similar conditions. From the evolution of the plume in helium, we found that an observation time of 3–5 μs and an observation height of about 2.5 mm are most suited for obtaining higher sensitivity. Observation times less than 3 μs were unsuitable for precise isotope analysis since the spectral modifications arising from the Doppler splitting effect are different between the two uranium isotopes. Using the established conditions, we evaluated the calibration curve linearity, limit of detection, and precision for three samples having different abundances of  235 U.

Description: Nondiffracting Bessel beams have been recently applied to single shot ultrafast laser processing of high aspect ratio nanochannels. We review the principles and benefits of nondiffracting Bessel beams for material processing, and we compare experimental results with numerical simulations. We show how the stationarity of nonlinear propagation of ultrafast laser pulses allows high aspect ratio material processing.

Description: Electrical conductivity, Hall effect and magnetoresistance of In 2 O 3 :Sn thin films deposited on a glass substrates at different temperatures and oxygen pressures, have been investigated in the temperature range 4.2–300 K. The observed temperature dependences of resistivity for films deposited at 230 °C as well as at nominally room temperatures were typical for metallic transport of electrons except temperature dependence of resistivity of the In 2 O 3 :Sn film deposited in the oxygen deficient atmosphere. The electrical measurements were accompanied by AFM and SEM studies of structural properties, as well as by XPS analysis. It is established that changes of morphology and crystallinity of ITO films modify the low-temperature behavior of resistivity, which still remains typical for metallic transport. This is not the case for the oxygen deficient ITO layer. XPS analysis shows that grown in situ oxygen deficient ITO films have enhanced DOS between the Fermi level and the valence band edge. The extra localized states behave as acceptors leading to a compensation of n -type ITO. That can explain lower n -type conductivity in this material crossing over to a Mott-type hopping at low temperatures. Results for the low temperature measurements of stoichiometric ITO layers indicate that they do not show any trace of metal-to-insulator transition even at 4.2 K. We conclude that, although ITO is considered as a highly doped wide-band gap semiconductor, its low-temperature properties are very different from those of conventional highly doped semiconductors.

Description: Background and aims Cadmium (Cd) could activate activity of mitogen-activated protein kinase MPK6 in plants. In this study, we investigated the role of MPK6 in mediating Cd toxicity in plants. Methods The wild type Arabidopsis plants (WT) and the mpk6 - 2 mutants were subjected either 0 (Control) or 10 μM Cd treatment. Kinase activity of MPK6, nitric oxide (NO) level, Cd concentration, and oxidative stress were measured. Results In WT plants, Cd exposure rapidly stimulated kinase activity of MPK6. However, upon Cd exposure, mpk6 - 2 showed better growth than the WT. Although Cd-induced production of NO in roots was greater in WT than in mpk6 - 2 , there was no difference in Cd concentration between the two plants. Nevertheless, the Cd-induced hydroperoxide burst, lipid peroxidation and loss of membrane integrity, were all more severe in the WT than in mpk6 - 2 . Foliar applications of antioxidant ascorbic acid, vigorously improved the growth of both the WT and mpk6 - 2 under Cd exposure. Thereby the growth difference between these two plants was minimized. Conclusions Mutation of mpk6 enhances Cd tolerance in plants by alleviating oxidative stress, but did not affect cadmium accumulation in plants.

Description: Background and Aims The role and linkage of endophytic bacteria to resistance of peanut seeds to biotic stress is poorly understood. The aims of the present study were to survey the experimental (axenic) and control (conventional) peanut plants for the predominant endophytic bacteria, and to characterize isolates with activity against selected A. flavus strains. Methods Young axenic plants were grown from presumably bacteria-free embryos in the lab, and then they were grown in a field. Endophytic bacterial species were identified by the analysis of DNA sequences of their 16S-ribosomal RNA gene. DNA extracted from soil was also analyzed for predominant bacteria. Results Mature seeds from the experimental and control plants contained several species of nonpathogenic endophytic bacteria. Among the eight bacterial species isolated from seeds, and DNA sequences detected in soil, Bacillus thuringiensis was dominant. All B. amyloliquefaciens isolates, the second abundant species in seeds demonstrated activity against A. flavus . This effect was not observed with any other bacterial isolates. There was no significant difference in number and relative occurrence of the two major bacterial species between the experimental and conventionally grown control seeds. Conclusion Endophytic bacterial colonization derives from local soil and not from the seed source, and the peanut plant accommodates only selected species of bacteria from diverse soil populations. Some bacterial isolates showed antibiosis against A. flavus.

Description: Background and Aims Climate warming and increased atmospheric nitrogen (N) deposition both have the potential to increase plant productivity over the next century, yet they can also increase decomposition and respiration. Our aim was to examine the extent to which warming and N addition can, on balance, alter net ecosystem CO 2 exchange (NEE) in a grass-dominated system. Methods We measured NEE responses to warming and N addition over two growing seasons in a temperate old field using steady-state flow-through chambers, which allowed for the integrated measurement of respiration and photoassimilation effects on net CO 2 flux over diel periods. We also assessed the relationship between NEE and plant biomass responses to the warming and N treatments. Results In both years, our study system was a net source of carbon (C) during the snow-free season. N addition did not significantly affect diel NEE or dark respiration in either year, despite a doubling in aboveground plant biomass in response to N addition in the second year, and a corresponding increase in peak daily net CO 2 photoassimilation in N addition plots. The warming treatment also had no significant effect on NEE, although the flow-through chambers required warming to be temporarily halted during NEE measurements. Conclusions Overall, our results both highlight the potential divergence of plant and soil responses to N addition and demonstrate the capacity for a grass-dominated system to function as a net source of C in consecutive years.

Description: Background and aim Intuitively, access to water from the soil at key phenological stages is important for adaptation to drought. This study aimed to assess the temporal pattern of water extraction under terminal drought stress. Methods Pearl millet genotypes with varying levels of terminal drought tolerance were grown in a lysimetric system with a soil volume and plant spacing similar to field conditions. Water extraction was monitored until maturity under differing water regimes. Results The yield did not differ among genotypes under well-watered (WW) conditions, and the water extraction profile of WW plants was similar across all genotypes. In contrast, the yield of sensitive genotypes was 30–100 % lower than that of tolerant lines under water stress (WS). The total volumes of water extracted by tolerant and sensitive genotypes were similar under WS; however, tolerant genotypes extracted less water prior to anthesis, and more water after anthesis. Grain yield was positively related to the amount of water extracted during week three after panicle emergence. Increased water extraction after anthesis benefitted the tillers more than the main culm and was correlated with higher staygreen scores. Conclusion Increased water uptake after anthesis, which results from earlier water conservation during pre-anthesis, increases yield under terminal drought in pearl millet.

Description: Background and aims Efficient accumulation of arsenic (As) in rice ( Oryza sativa L.) poses a potential health risk to rice consumers. The aim of this study was to investigate the mechanisms of uptake, transport and distribution of inorganic arsenic (As i ) and dimethylarsinic acid (DMA) in rice plants. Methods Rice was exposed to As i (As(V)) and DMA in hydroponics. High-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) and synchrotron X-ray fluorescence (SXRF) microprobe were used to determine As concentration and the in situ As distribution. Results DMA induced abnormal florets before flowering and caused a sharp decline in the seed setting rate after flowering compared to As i . Rice grains accumulated 2-fold higher DMA than As i . The distribution of As i concentration (root 〉 leaf 〉 husk 〉 caryopsis) in As(V) treatments was different from that of the DMA concentration (caryopsis 〉 husk 〉 root ≥ leaf) in DMA treatments. SXRF showed that As i mainly accumulated in the vascular trace of caryopsis with limited distribution to the endosperm, whereas DMA was observed in both tissues. Conclusions DMA tended to accumulate in caryopsis and induced higher toxicity to the reproductive tissues resulting in markedly reduced grain yield, whereas As i mainly remained in the vegetative tissues and had no significant effect on yield. DMA is more toxic than As i to the reproductive tissues when both of them are at similar concentrations in nutrient solution.

Description: Background and aims Variations in responses to soil N between a non-N-fixing shrub, Baccharis halimifolia L., and a N-fixing shrub, Morella cerifera (L.) Small, were tested over 12 weeks to determine whether N availability is the sole cause of persistent dominance of M. cerifera on barrier islands. Methods Plants were supplied increasing levels of soil N up to 200 mg kg −1 . Measurements included gas exchange and chlorophyll fluorescence parameters across treatments, species, and time. Tissues were analyzed for differences in biomass and nutrients. Results Baccharis halimifolia had reduced physiological responses across all treatment levels, but M. cerifera had comparatively few variations. Across all treatments B. halimifolia photosynthesis and stomatal conductance were reduced by 62 and 76 %, respectively,by week 12. Increasing foliar δ 15 N values across treatments for M. cerifera indicated a shift from utilizing fixed N to available soil N. Biomass was highest at 200 mg kg −1  N for both species. Baccharis halimifolia showed indications of stress response and resource limitation based on physiological responses, nutrient contents, and isotope effects. Conclusions Baccharis halimifolia showed signs of co-limitation of both N and P whereas M. cerifera was limited by neither, suggesting that dominance of M. cerifera is only partially explained by actinorhizal symbiosis and N availability.

Description: Background and Aims Soil mineralization, nitrification, and dynamic changes in abundance of ammonia-oxidizing bacteria (AOB) and archaea (AOA) were studied to validate our hypothesis that soil mineralization and nitrification decreased along the chronosequence of rice cultivation. Methods Paddy soils with a 300, 700 and 2000-year cultivation history (P300, P700 and P2000) were selected to study net mineralization and nitrification processes. Dynamic abundance of AOB and AOA was estimated by quantifying their respective amoA gene copies. Results The net mineralization rate was higher for P300 than P700 and P2000. Potential nitrification ( N p ) and average nitrification rates ( V a ) were similar for P300 and P700 soils, but the simulated potential nitrification rate ( V p ) and nitrification rate (k 1 ) was 72 % and 88 % higher for P300 than P700, respectively. V a was about 70 % lower than for P2000 than P300 and P700. AOB amoA gene copies were higher for P300 than P700 and P2000, whereas AOA abundance did not show significant differences. AOB abundance showed a positive response to NH 4 supply but AOA did not. Conclusions Both N mineralization and nitrification were depressed with increased cultivation time. Archaea responded to mineralization positively rather than nitrification, which suggested that readily mineralized organic matter may play an important role in AOA.

Description: Aims The current study aimed to assess the potential of peanut ( Arachis hypogaea L.) for bioenergy production via phytoextraction in cadmium (Cd) -contaminated soils and screen appropriate cultivars for this approach. Methods A life-cycle pot experiment was conducted to determine the biomass, seed yield, oil content and Cd accumulation of seven peanut cultivars under Cd concentration gradients of 0, 2, and 4 mg kg −1 . Results Peanut exhibits genotypic variations in Cd tolerance, seed production, oil content, and Cd accumulation. Exposure of plants to 2 and 4 mg kg −1 Cd did not inhibit shoot biomass, seed yield, and oil content for most of the cultivars tested. There are large amounts of Cd accumulated in the shoots. Although the seed Cd concentration of peanut was relatively high, the Cd concentration in seed oils was very low (0.04-0.08 mg kg −1 ). Among the cultivars, Qishan 208 showed significant Cd tolerance, high shoot biomass, high pod and seed yield, high seed oil content, considerable shoot Cd concentration, and the largest translocation factor and total Cd in shoots. Conclusions The cultivation of peanut in Cd-contaminated farmland was confirmed to be feasible for bioenergy production via phytoextraction, and Qishan 208 is a good candidate for this approach.

Description: Background and aims Sufficient soil phosphorus (P) is important for achieving optimal crop production, but excessive soil P levels may create a risk of P losses and associated eutrophication of surface waters. The aim of this study was to determine critical soil P levels for achieving optimal crop yields and minimal P losses in common soil types and dominant cropping systems in China. Methods Four long-term experiment sites were selected in China. The critical level of soil Olsen-P for crop yield was determined using the linear-plateau model. The relationships between the soil total P, Olsen-P and CaCl 2 -P were evaluated using two-segment linear model to determine the soil P fertility rate and leaching change-point. Results The critical levels of soil Olsen-P for optimal crop yield ranged from 10.9 mg kg −1 to 21.4 mg kg −1 , above which crop yield response less to the increasing of soil Olsen-P. The P leaching change-points of Olsen-P ranged from 39.9 mg kg −1 to 90.2 mg kg −1 , above which soil CaCl 2 -P greatly increasing with increasing soil Olsen-P. Similar change-point was found between soil total P and Olsen-P. Overall, the change-point ranged from 4.6 mg kg −1 to 71.8 mg kg −1 among all the four sites. These change-points were highly affected by crop specie, soil type, pH and soil organic matter content. Conclusions The three response curves could be used to access the soil Olsen-P status for crop yield, soil P fertility rate and soil P leaching risk for a sustainable soil P management in field.

Description: Background and aims Gaseous losses of ammonia (NH 3 ) have been observed in citrus orchards when urea is surface-applied to the soils, and this loss might significantly limit the effectiveness of the nitrogen (N) fertilizer. However, a portion of the volatilized NH 3 might be absorbed by the plants through the leaves. To quantify the contribution of the leaf absorption of 15 NH 3 , a study with sweet oranges was conducted in two field areas where trees were grown at standard (480 trees ha −1 ) and high densities (617 trees ha −1 ). Methods Plastic trays were filled with soil, covered with mown grass to simulate field management conditions, fertilized with 15 N labeled urea (12 atom % excess) and placed under each of three trees in the orchards. This experimental procedure prevented the uptake of N from the labeled urea by the roots. Two weeks after 15 N fertilization, the trays were removed from the field, and the soil was homogenized and sampled for chemical analyses. The citrus trees under which the trays were placed were destructively harvested, and the total N concentrations and 15 N/ 14 N ratios were determined. Results After urea application, the NH 3 losses peaked within three days and subsequently decreased to negligible amounts after 10 days. The total NH 3 losses accounted for 55–82 % of the applied N. Although the NH 3 absorption by the citrus leaves was proportional to the tree density in the field, only 3–7 % of the 15 NH 3 volatilized from the soil was recovered by the citrus trees, and the NH 3 absorption was also influenced by the proximity of citrus trees to the site of urea application and the leaf areas of the trees. Conclusions The citrus trees can absorb the NH 3 volatilized from urea, even though, the amount recovered by the trees is small and does not represent a significant proportion of total gaseous N losses, what demonstrates the importance of enhanced N use efficiency practices in field to reduce losses of NH 3 when urea is applied to soil surfaces.

Description: Background Rice can accumulate arsenic (As) to relatively high concentrations due to the general flooding practices in rice cultivation, and organic matter in the soil strongly affected As bioavailability to rice plants. The influence of organic matter input on the As transformation in paddy soil and As uptake into rice plants is an area that is rarely investigated. Methods Biogas slurry (BGS), a commonly used organic fertilizer, was applied to an As contaminated paddy soil, in order to investigate the influence of organic matter on As transformation in the paddy soil and As accumulation in rice plants. Results Application of BGS significantly increased the As accumulation in rice plants, especially for methylated As species. Results showed that the concentrations of dissolved organic carbon (DOC) and dissolved Fe(II) in the soil solution were significantly increased by the BGS addition into the paddy soil, and were significantly correlated to the As concentration in the soil solution ( P  〈 0.01). The increase of soil pH and the decrease of the soil redox potential (Eh) were observed as well. These alteration of soil characteristics elevated the As release from soil particles to the soil solution under the addition of BGS. The increased concentrations of dimethylarsinic acid (DMAs(V)) and monomethylarsonic acid (MMAs(V)) in the soil solution, and the volatilized As of trimethylarsine (TMAs) from the paddy soil, suggested that As methylation and volatilization in the soil were also enhanced by BGS addition. The concentrations of methylated As species in rice husks and grains were increased by 105.8–105.9 % and 99.7–112.2 %, respectively. Conclusion These results suggested that the use of organic fertilizer, such as BGS in As-contaminated paddy soil, can significantly alter the behavior of As in soil-rice system and enhance As accumulation in rice plants and should therefore be avoided.

Description: Ion implantation was used to locally modify the surface of silica glass to create periodic plasmonic microstructures with Cu nanoparticles. Nanoparticles were synthesized by Cu-ion irradiation of the silica glass at the ion energy of 40 keV, dose of 5×10 16  ions/cm 2 and current density of 5 μA/cm 2 . This procedure involves low-energy ion implantation into the glass through a mask placed at the surface. Formation of nanoparticles was observed by optical spectroscopy and atomic force microscopy. The presented results clearly demonstrate how the low-energy ions can be used for the fabrication of photonic microstructures on dielectric surfaces in a single-step process.

Description: Au/Nb:SrTiO 3 /Ti structures were fabricated by depositing Au and Ti electrodes on a single crystal 0.5 wt% Nb:SrTiO 3 (NSTO) using rf-magnetron sputtering technique. Resistive switching properties at different temperature were investigated. The Ti/NSTO interface was ohmic contact, which indicated that the resistive switching behavior was attributed to Au/NSTO interface. The resistive switching behavior happened only at the temperature above 180 K, which was possibly caused by the increase of Schottky barrier height with the increase of temperature. The structure showed a semiconductor behavior at high-resistance state (HRS) and a metallic behavior at low-resistance state (LRS). The switching conduction mechanism of Au/NSTO/Ti device is primarily described as space-charge-limited conduction (SCLC) according to the electrical transport properties measurement.

Description: The ZnO nanowire (NW) array/TiO 2 nanoparticle (NP) composite photoelectrode with controllable NW aspect ratio has been grown from aqueous solutions for the fabrication of dye-sensitized solar cells (DSSCs), which combines the advantages of the rapid electron transport in ZnO NW array and the high surface area of TiO 2 NPs. The results indicate that the composite photoelectrode achieves higher overall photoelectrical conversion efficiency ( η ) than the ZnO NW alone. As a result, DSSCs based on the ZnO NW array/TiO 2 NP composite photoelectrodes get the enhanced photoelectrical conversion efficiency, and the highest η is also achieved by rational tuning the aspect ratio of ZnO NWs. With the proper aspect ratio (ca. 6) of ZnO NW, the ZnO NW array/TiO 2 NP composite DSSC exhibits the highest conversion efficiency (5.5 %). It is elucidated by the dye adsorption amount and interfacial electron transport of DSSCs with the ZnO NW array/TiO 2 NP composite photoelectrode, which is quantitatively characterized using the UV-Vis absorption spectra and electrochemical impedance spectra. It is evident that the DSSC with the proper aspect ratio of ZnO NW displays the high dye adsorption amount and fastest interfacial electron transfer.

Description: We report the photoluminescence eigenmodes of the ZnO semiconductor microcavity on a Ag/Si substrate at room temperature. The experiment results show that the photoluminescence modes do not depend on the excitation intensity. The eigenmode in the microcavity is considered to be the perpendicular Fabry–Perot modes, where the effect of the strong coupling between plasmon and exciton is observed with the reducing of the effective refractive index from original 2.0 to 1.67 at the wavelength of 585 nm. Meanwhile, there is also a coupling between the plasmon and the exciton-polariton in the band-edge region, and the effective refractive index 1.92 is in good agreement between the experimental and the theoretical results.

Description: Variations in the switching threshold voltage of memristive devices present significant challenges for their integration into large-scale circuits. In this paper, we propose to address this problem by adding a device exhibiting S-type (N-type) negative differential resistance (NDR) in series (parallel) with memristive devices. The main effect comes from the transition between low- and high-conductivity branches of the NDR device, which leads to a redistribution of the voltage drop inside the device stack, and, as a result, the effective lowering of variations in the switching threshold. The idea is checked experimentally using a TiO 2− x memristive device connected in parallel with a tunnel GaAs diode.

Description: The detailed chemical analysis of fossils has the potential to reveal great insight to the composition, preservation and biochemistry of ancient life. Such analyses would ideally identify, quantify, and spatially resolve the chemical composition of preserved bone and soft tissue structures, but also the embedding matrix. Mapping the chemistry of a fossil in situ can place constraints on mass transfer between the enclosing matrix and the preserved organism(s), and therefore aid in distinguishing taphonomic processes from original chemical zonation remnant within the fossils themselves. Conventional analytical methods, such as scanning electron microscopy (SEM) and pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) have serious limitations in this case, primarily, an inability to provide large (i.e., decimeter) scale chemical maps. Additionally, vacuum chamber size and the need for destructive sampling preclude analysis of large and precious fossil specimens. However, the recent development of Synchrotron Rapid Scanning X-ray Fluorescence (SRS-XRF) at the Stanford Synchrotron Radiation Lightsource (SSRL) allows the non-destructive chemical analysis and imaging of major, minor, and trace element concentrations of large paleontological and archeological specimens in rapid scanning times. Here we present elemental maps of a fossil reptile produced using the new SRS-XRF method. Our results unequivocally show that preserved biological structures are not simply impressions or carbonized remains, but possess a remnant of the original organismal biochemistry. We show that SRS-XRF is a powerful new tool for the study of paleontological and archaeological samples.

Description: Here for the first time we describe the use of high resolution nanoprobe X-ray fluorescence (XRF) mapping for the analysis of artists’ paints, hierarchically complex materials typically composed of binder, pigments, fillers, and other additives. The work undertaken at the nanoprobe sought to obtain highly spatially resolved, highly sensitive mapping of metal impurities (Pb, Cd, Fe, and other metals) in submicron particles of zinc oxide pigments used in early 20th century artists’ tube paints and enamel paints, with particular emphasis on Ripolin, a popular brand of French house paint used extensively by Pablo Picasso and some of his contemporaries. Analysis revealed that the Zn oxide particles only contain a little Fe, proving that the highest quality Zn oxide pigment, free of Pb and Cd, was used for Ripolin house paints as well as artists’ paints. Nanoprobe XRF mapping also demonstrated that artists’ tube paints generally have more abundant fillers and additional whites (based on Pb, Ti, Ca) than Ripolin paints, which contain mostly pure zinc oxide. The chemical characterization of paints at the nanoscale opens the path to a better understanding of their fabrication and chemical reactivity.

Description: We fabricated sulfur-doped black silicon by metal-assist chemical etching (MCE) and ion implanting. The morphologies of silicon nanowire (SiNW) arrays and the concentration of sulfur in black silicon were analyzed by scanning electron microscope (SEM). Sulfur-doped black silicon shows higher absorption in entire 0.3–2.5 μm wavelength range as compared to undoped SiNW arrays and flat silicon. The changes in the absorption spectra of black silicon with different etching durations and annealing temperature are also shown. Upon annealing, the absorption decreases significantly in 2–2.5 μm wavelength region. The novel results clearly indicate that sulfur implanting could produce below band gap absorption in the silicon substrate.

Description: The wettability of solid surface is a very important property of materials, which depends on both surface chemical composition and the geometry of the solid surface. We herein report a simple and inexpensive method to fabricate superhydrophobic surfaces with the use of mullite whisks (MWs) for the first time. Binary micro-/nano-structural surfaces were created by the incorporation of hydrophilic needlelike MWs with poly( γ -methacryloxypropyltrimethoxysilane) to exhibit hydrophobic behavior, which further showed superhydrophobicity with water contact angle of 152.4±2 ∘ after modified with stearic acid. The wettability variation from hydrophilicity to hydrophobicity and superhydrophobicity during the assembly process are discussed based on the scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and contact-angle system. The superhydrophobicity of the surface could be attributed to the hierarchical microstructure of the rough surface induced by MWs and low surface energy of stearic acid.

Description: Luminescent properties of ZnO nanorods covered with Ag nanoparticles are examined. Nanorods were synthesized on AAO templates using Atomic Layer Deposition (ALD) technique. Two types of the samples were prepared with different arrangement of ZnO nanorods and doping conditions. Nanorods of the second type were codoped with Al, to stimulate defect-related emissions. The ZnO material fills heterogeneously the interior of the AAO nanopores and has hexagonal, wurtzite structure. Both types of structures exhibit a broad defect-related emission at about 440 nm, most probably related to recombination at zinc interstitial (Zn i ) defects. This emission in samples with a random distribution of ZnO:Al nanorods and finer Ag nanoparticles is enhanced by factor of ∼2.5 upon Ag deposition. The so-obtained material is interesting from the point of view of its application in blue range emitting diodes.

Description: The separation mechanism of opaque and transparent model micro-particles, graphite and polystyrene copolymer spheres, respectively, from polymethyl methacrylate (PMMA) substrates were investigated employing a ns-pulse laser radiating at 532 nm. The particles transparent in the visible wavelength range could be removed from PMMA efficiently in a very narrow fluence range between 1 and 2 J/cm 2 according to a simple 1D thermal expansion model. Above this fluence region, with single pulses, the transparent microspheres caused local ablation of the PMMA substrate in the optical microlens nearfield. This process led to removal of the particles themselves due to the expansion of the ablation plasma. The irregularly shaped graphite particles shaded the underlying substrate from the incoming radiation so that no optical nearfield damage mechanism could be observed. Therefore, a substantial cleaning window between 0.5 and more than 16 J/cm 2 was provided. The graphite data suggest an ablation mechanism of the particulates themselves due to a high optical absorption coefficient.

Description: Background & aims Plants may have dissimilar effects on ecosystem processes because they possess different attributes. Given increasing biodiversity losses, it is important to understand which plant traits are key drivers of ecosystem functions. To address this question, we studied the response of two ecosystem functions that remove nitrogen (N) from wetland soils, the accumulation of N in plant biomass and denitrification potential (DNP), to variation in plant trait composition. Methods Our experiment manipulated plant composition in a riparian wetland. We determined relative importance of plant traits and environmental variables as predictors of each ecosystem function. Results We demonstrate that Water Use Efficiency (WUE) had a strong negative effect on biomass N. Root porosity and belowground biomass were negatively correlated with DNP. Trait ordination indicated that WUE was largely orthogonal to traits that maximized DNP. Conclusions These results indicate that plant species with different trait values are required to maintain multiple ecosystem functions, and provide a more mechanistic, trait-based link between the recent findings that higher biodiversity is necessary for multi-functionality. While we selected plant traits based on ecological theory, several of the plant traits were not good predictors of each ecosystem function suggesting the ecological theory linking traits to function is incomplete and requires strengthening.

Description: The solid-state reaction in Pt(15 nm)/Fe(15 nm) and Pt(15 nm)/Ag(10 nm)/Fe(15 nm) thin films after post-annealing at 593 K and 613 K for different annealing times has been studied. The structural properties of these samples were investigated by various methods including depth profiling with secondary neutral mass spectrometry, transmission electron microscopy, and X-ray diffraction. It is shown that after annealing at the above temperatures where the bulk diffusion processes are still frozen, homogeneous reaction layers of FePt and FePt with about 10 at.% Ag, respectively, have been formed. Corresponding depth profiles of the element concentrations revealed strong evidence that the formation mechanism is based on a grain boundary diffusion induced solid-state reaction in which the reaction interfaces sweep perpendicularly to the original grain boundary. Interestingly, X-ray diffraction indicated that in both thin-film systems after the solid-state reaction the ordered L1 0 FePt phase, which is the requested phase for future magnetic data storage applications, is also present.

Description: Aims Wild soybean accession PI 468917 [ Glycine soja (Sieb. and Zucc.)] was examined for traits that could potentially be beneficial for development of drought resistant soybean cultivars. Methods Water use was examined in controlled environment chambers at three temperatures (25, 30, and 35 °C). Root morphology of plants grown in hydroponics was analyzed using digital imaging software. Results Wild soybean had lower transpiration efficiency in producing mass than the domesticated soybean cultivar Hutcheson at all temperatures. As soil dried, wild soybean decreased transpiration earlier (at a higher soil water content) than domesticated soybean, but only at 25 °C. Wild soybean had much greater root length than the modern soybean when grown at 25 or 30 °C in hydroponics, with the increase observed in the 0.25 to 0.50 mm diameter class. Wild soybean’s advantages dissipated at higher growth temperatures. Conclusions Wild soybean populations, potentially, can offer useful traits for improving drought resistance of modern soybean. Sensitive transpiration control in response to soil drying would contribute to ‘slow-wilting’ strategies known to be advantageous for drought resistance, and greater root length would enhance water acquisition from the soil profile. Use of the traits in breeding programs will require extending the temperature range for trait expression.

Description: Multiferroic bismuth ferrite (BiFeO 3 ) has attracted considerable attention due to applications related to the bulk photovoltaic effect in which the direction of polarization determines the direction of the photocurrent. Epitaxial thin films are produced by means of techniques that usually require high temperature processes. The hydrothermal method can be seen as an alternative route to obtain highly textured thin films in quantities compatible with batch processing; nevertheless, the structural, dielectric and electric properties are generally affected by the presence of hydrogen and other reaction by-products. In this work, functional and highly textured BiFeO 3 films were successfully produced on metallic SrTiO 3 :Nb (0.5 wt.%) (100) substrates via hydrothermal synthesis. X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) were used to analyze the structural properties of the films. Piezoresponse Force Microscopy (PFM) and Photoconductive Atomic Force Microscopy (Pc-AFM) were used to determine their functional properties. We show the polarization switching and confirm the presence of the bulk photovoltaic effect for the first time in hydrothermally synthesized BiFeO 3 .