Entire Pool Research Articles

The impact of Acacia saligna on the composition and structure of the Mediterranean maquis

ABSTRACT We evaluated the ecological impacts of the invasive alien species (IAS) Acacia saligna on the vegetation composition and structure of two coastal dunes woody habitats of Union concern (2250*: coastal dunes with Juniperus spp. and 2260: dunes with sclerophyllous vegetation consisting of Cisto-Lavanduletalia). We sampled 20 paired plots per habitat type under invaded (A. saligna cover > 70%) and non-invaded conditions, following a stratified random protocol. We tested the differences between invaded and non-invaded plots in terms of species composition of the entire species pool and of different ecological guilds and growth forms. Our findings showed that the invaded maquis (habitat 2260) had a significant decline in median richness (5 vs 2) and median cover (24.50 vs 8.00) of focal species and a significant increase in median cover of ruderal species (2.00 vs 5.50). The invaded juniper shrubs (EU habitat 2250*) preserved the typical species composition, but with significant variations in vegetation structure. The approach adopted in this study, accompanied by the results obtained, contribute towards fulfilling EU Regulation 1143/2014 on IAS. Key policy insights Results reveal worrying levels of biodiversity loss on coastal dunes due to the invasion of the invasive alien species (IAS) Acacia saligna. We detected remarkable changes in the physiognomy of the Mediterranean maquis coastal dunes – a landscape that is losing its biological uniqueness. The spread of A. saligna is having negative ecological effects upon the conservation status of two habitats of Union concern (codes 2250* and 2260). Urgent preventive measures, effective control strategies and eradication of A. saligna must be implemented across the Mediterranean Nature 2000 Coastal Protected Areas Network. The approach adopted and results obtained contribute to fulfilling EU Regulation 1143/2014 on IAS.

Assessment of grain productivity and adaptability of domestic and foreign varieties of spring barley in the non-chernozem zone of the Russian federation

Evaluation of 160 collection samples during 2016-2020 in the conditions of the Moscow region on the level and limits of yield, on the indicators of plasticity and stability was carried out in order to reveal their adaptive potential. A high degree of yield dependence on the conditions of the growing season of barley was revealed. The highest productivity potential is found in samples of Belarus (7.37 t/ha), Germany (7.17 t/ha) and France (7.26 t/ha). The smallest difference between the yield under contrasting conditions determined the increased stress resistance of Kazakhstan collection numbers. Due to a positive combination of high potential productivity and increased resistance to biotic environmental factors, the Belarusian group of varieties exceeded the average annual yield of the entire gene pool by 6.0%. In relation to the main problems of breeding, the best forms that are most promising for further breeding work to increase adaptive potential were selected: Reliable, (Moscow region); Bagret, K-30988 (Sverdlovsk region); Magutny, K-31149, Radzimich, VA 08000190, Fest, VA 08000191, Vodar, K-31146, Khago, K-31147 (Belarus) Solntsedar, K-31098 (Ukraine); Graice, K-31216, Sunshine, K-31129 (Germany); Pioneer, K-31250 (France). Samples with high responsiveness to improvement of cultivation conditions (bi=1.02-1.33), which are of practical interest to increase the productivity potential - Reliable, Bagret, Magutny, Radzimich, Fest, Hago, Grace. Special attention should be paid to the varieties Vodar, Solntsedar and Sunshine, which are characterized as highly geostatic in terms of the level and stability of yield (PUSS=122.4-129.9). They are able to give a relatively high yield in favorable conditions, and due to genetic characteristics, they are less likely than other varieties to reduce it in contrast.

The GORKY glycoalkaloid transporter is indispensable for preventing tomato bitterness.

Fruit taste is determined by sugars, acids and in some species, bitter chemicals. Attraction of seed-dispersing organisms in nature and breeding for consumer preferences requires reduced fruit bitterness. A key metabolic shift during ripening prevents tomato fruit bitterness by eliminating α-tomatine, a renowned defence-associated Solanum alkaloid. Here, we combined fine mapping with information from 150 resequenced genomes and genotyping a 650-tomato core collection to identify nine bitter-tasting accessions including the 'high tomatine' Peruvian landraces reported in the literature. These 'bitter' accessions contain a deletion in GORKY, a nitrate/peptide family transporter mediating α-tomatine subcellular localization during fruit ripening. GORKY exports α-tomatine and its derivatives from the vacuole to the cytosol and this facilitates the conversion of the entire α-tomatine pool to non-bitter forms, rendering the fruit palatable. Hence, GORKY activity was a notable innovation in the process of tomato fruit domestication and breeding.

Impact of Asian and Black Donor and Recipient Ethnicity on the Outcomes after Deceased Donor Kidney Transplantation in the United Kingdom

Background: Patients of Asian and black ethnicity face disadvantage on the renal transplant waiting list in the United Kingdom, because of lack of HLA and blood group matched donors from an overwhelmingly white deceased donor pool. This study evaluates outcomes of renal allografts arising from Asian and black donors. Methods: The UK Transplant Registry was analysed for adult deceased donor kidney only transplants performed during January 2001-December 2015. Cox regression analysis was performed to identify and adjust for factors influencing 5-year graft outcome, and to study donor-recipient ethnicity interactions. Findings: Asian and black ethnicity patients constituted 12·4% and 6·7% of all deceased donor recipients but comprised only 1·6% and 1·2% of all deceased donors, respectively. Across all recipients, and unsurprisingly given the predominantly white recipient pool, HLA matching was superior for grafts from white donors than from Asian and black donors (p<0·0001). Unadjusted survival analysis demonstrated significantly inferior long-term allograft outcomes associated with Asian and black donors, compared to white donors (7-year graft survival 71·9%, 74·0% and 80·5%; log-rank p=0·0007, respectively). On Cox regression analysis, Asian donor and black recipient ethnicities were associated with poorer outcomes than white counterparts (p<=0·02), and when looking at ethnicity matching, compared with the white donor–white recipient baseline group and adjusting for other donor and recipient factors, 5-year graft outcomes were significantly poorer for black donor-black recipient [HR 1·92 (1·11-3·32), p=0·02], Asian donor-white recipient [HR 1·56 (1·09-2·24), p=0·02] and white donor-black recipient [HR 1·22 (1·05-1·42), p=0·01] combinations in decreasing order of worse unadjusted 5-year graft survival. Interpretation: Increased deceased donation among ethnic minority communities would benefit the entire recipient pool by increasing the numbers of available organs and may specifically benefit the Asian and black recipients by increasing the numbers of blood group and HLA-compatible grafts for allocation but may not improve allograft outcomes. Funding None to declare Declaration of Interest: None to declare

Disaggregated Accelerator Management System for Cloud Data Centers

A conventional data center that consists of monolithic-servers is confronted with limitations including lack of operational flexibility, low resource utilization, low maintainability, etc. Resource disaggregation is a promising solution to address the above issues. We propose a concept of disaggregated cloud data center architecture called Flow-in-Cloud (FiC) that enables an existing cluster computer system to expand an accelerator pool through a high-speed network. FlowOS-RM manages the entire pool resources, and deploys a user job on a dynamically constructed slice according to a user request. This slice consists of compute nodes and accelerators where each accelerator is attached to the corresponding compute node. This paper demonstrates the feasibility of FiC in a proof of concept experiment running a distributed deep learning application on the prototype system. The result successfully warrants the applicability of the proposed system.

Experimental study on flow characteristics of a large-scale open jet wind tunnel for outdoor pool fire research

An open jet wind tunnel with an exit area of 23 ​× ​9 ​m2 has been built to study the behaviors of large-scale pool fires under controlled wind conditions. A series of measurements on the mean and fluctuating wind velocities, using arrays of hot-wire probes and ultrasonic anemometers, were extensively performed in the transverse planes at the leading and trailing edges of the pool (28 ​m and 48 ​m to the exit). The entire pool was located in the potential core of the central jet flow region, and the longitudinal velocity (U) and turbulence intensity (Iu) exhibited acceptable uniform distributions within the two vertical planes. The mean turbulence intensities in the two planes were close to those in the flat open grassland and sea (7%–10%). The longitudinal velocity spectra were in good agreement with the Von Kármán spectrum at all levels, and the onset frequency for isotropy was about 1.5–3.0 ​Hz. In the central flow region, the turbulence dissipation rates (ε) were fitted well by ε ​= ​0.067U2.69Iu1.90, and the best-fit line for the turbulent diffusivity (νt) was νt ​= ​0.21U0.95Iu0.98. The detailed mean flow and turbulence characteristics provided the necessary information for the pool fire tests and numerical model verification.

Impact of β-range-induced oscillatory activity on human input–output relationship of the corticospinal pathway

ABSTRACT Objective: The aim of the study was to show that short-lasting (90 s) transcranial alternating current stimulation (tACS) at 20 Hz delivered over the left primary motor cortex (M1) is able to change the shape of recruitment curve of the corticospinal pathway. Methods: The corticospinal pathway was studied during tACS by means of the relationship between the intensity of transcranial magnetic stimulation (TMS) delivered over the left M1 and corresponding motor evoked potentials (MEPs) recorded from the right first dorsal interosseus muscle (FDI), in nine healthy subjects. In order to extract characteristics of the input–output relationship that have particular physiological relevance, data were fitted to the Boltzmann sigmoidal function by the Levenberg–Marquardt nonlinear, least mean squares algorithm. Results: The β-rhythm tACS influenced the shape and parameters of the input–output relation, so that the initial segment of the conditioned curve (from threshold to 30% of maximum muscle size) diverged, while the subsequent segment converged to overlap the unconditioned control curve. Discussion: β-rhythm tACS conditions only a definite subset of corticospinal elements influencing less than 30% of the entire motoneuronal pool. The fact that β-rhythm tACS mainly affects the most excitable motoneurons could explain the observed antikinetic effect of the tACS at β-rhythm applied in the motor regions.

Promising anti- cervical carcinoma and inflammatory agent, Resveratrol targets poly (ADP-ribose) polymerase 1 (PARP-1) induced premature ovarian failure with a potent enzymatic modulatory activity

Radioprotective effects of Resveratrol is well known in normal cells exposed to the damaging effects of ionizing radiation however, its potential radioprotective effect on ovarian follicle formation and development is still uncertain. Astonishingly, it has been reported that PARP contributed to the pathogenesis of immune-mediated ovarian injury. In this paper, Resveratrol was tested for its inflammatory, anti-cervical carcinoma activity, and checked its targets poly (ADP-ribose) polymerase 1 (PARP-1) induced premature ovarian failure with a potent enzymatic modulatory activity. Through high-throughput virtual screening method, Resveratrol was screened to find its target. That the compound strongly inhibited cervical carcinoma HT-3 cell. The cell proliferation was evaluated by an CCK-8 assay, and the cell apoptosis was assessed by a flow cytometry. Rat model of premature ovarian failure was used to introduce resveratrol preparation and rtPCR was done to measure expression of apoptosis related markers. We report resveratrol as a potential target for PARP-1 and its modulator from a high-throughput virtual screening method. Resveratrol was measured its anti-cervical carcinoma activity by using an CCK-8 assay, which suggested that the compound strongly inhibited HT-3 cell proliferation, the IC50 value is 0.65 μM. In addition, the compound induced HT-3 cell apoptosis in a dose-response manner. Resveratrol preserves the entire ovarian follicle pool manifested by increasing serum anti-Müllerian hormone (AMH) levels. Study suggest that resveratrol restored ovarian function through increasing AMH levels, and diminishing ovarian inflammation, predominantly modulation of PPAR-1 and inhibition of inflammatory cytokines. Resveratrol was identified targets for PARP-1 from a high-throughput virtual screening method, strongly inhibited PARP-1 protein and HT-3 cell proliferation. Resveratrol is a promising PARP-1 modulator with anti-cervical carcinoma activity, which deserves further investigation.

Theoretical Analysis of the Built-in Metabolic Pathway Effect on the Metabolism of Erythrocyte-Bioreactors That Neutralize Ammonium.

The limitations of the efficiency of ammonium-neutralizing erythrocyte-bioreactors based on glutamate dehydrogenase and alanine aminotransferase reactions were analyzed using a mathematical model. At low pyruvate concentrations in the external medium (below about 0.3 mM), the main limiting factor is the rate of pyruvate influx into the erythrocyte from the outside, and at higher concentrations, it is the disappearance of a steady state in glycolysis if the rate of ammonium processing is higher than the critical value (about 12 mM/h). This rate corresponds to different values of glutamate dehydrogenase activity at different concentrations of pyruvate in plasma. Oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) by glutamate dehydrogenase decreases the fraction of NADPH in the constant pool of nicotinamide adenine dinucleotide phosphates (NADP + NADPH). This, in turn, activates the pentose phosphate pathway, where NADP reduces to NADPH. Due to the increase in flux through the pentose phosphate pathway, stabilization of the ATP concentration becomes impossible; its value increases until almost the entire pool of adenylates transforms into the ATP form. As the pool of adenylates is constant, the ADP concentration decreases dramatically. This slows the pyruvate kinase reaction, leading to the disappearance of the steady state in glycolysis.

Intact in situ Preparation of the Drosophila melanogaster Lymph Gland for a Comprehensive Analysis of Larval Hematopoiesis.

Blood cells have a limited lifespan and are replenished by a small number of hematopoietic stem and progenitor cells (HSPCs). Adult vertebrate hematopoiesis occurs in the bone marrow, liver, and spleen, rendering a comprehensive analysis of the entire HSPC pool nearly impossible. The Drosophila blood system is well studied and has developmental, molecular, and functional parallels with that of vertebrates. Unlike vertebrates, post-embryonic hematopoiesis in Drosophila is essentially restricted to the larval lymph gland (LG), a multi-lobed organ that flanks the dorsal vessel. Because the anterior-most or primary lobes of the LG are easy to dissect out, their cellular and molecular characteristics have been studied in considerable detail. The 2-3 pairs of posterior lobes are more delicate and fragile and have largely been ignored. However, posterior lobes harbor a significant blood progenitor pool, and several hematopoietic mutants show differences in phenotype between the anterior and posterior lobes. Hence, a comprehensive analysis of the LG is important for a thorough understanding of Drosophila hematopoiesis. Most studies focus on isolating the primary lobes by methods that generally dislodge and damage other lobes. To obtain preparations of the whole LG, including intact posterior lobes, here we provide a detailed protocol for larval fillet dissection. This allows accessing and analyzing complete LG lobes, along with dorsal vessel and pericardial cells. We demonstrate that tissue architecture and integrity is maintained and provide methods for quantitative analysis. This protocol can be used to quickly and effectively isolate complete LGs from first instar larval to pupal stages and can be implemented with ease.

Мониторинг инфицирования и резистентности Achromobacter xylosoxidans у взрослых пациентов с муковисцидозом

Aim: to evaluate the infection rate and resistance of isolated Achromobacter xylosoxidans to carbapenems in adult cystic fibrosis patients (CF). Patients and Methods: a retrospective analysis of the results of culture test and time-of-flight mass spectrometry MALDI-TOF was conducted: 685 sputum samples of 58 adult CF patients for a period of 5 years (2016–2020). To assess the sensitivity to imipenem and meropenem, the agar gradient diffusion and disk diffusion method were used. Results: the incidence of infection with A. xylosoxidans in adult CF patients for the period from 2016 to 2020 when monitoring a single sample of patients (n=24) to evaluate the occurrence of this pathogen with increasing age ranged from 16.6% in 2016–2017, increasing to 37.5% in 2018–2019, and with a further reduction to 20.8% (associated with disease fatal outcome in 3 of the 9 infected patients). There was no statistically significant dependence of the fatal outcome on infection with A. xylosoxidans. When analyzing the entire pool of patients (n=58) from 2016 to 2020, the release frequency of Pseudomonas aeruginosa remains approximately the same, varying from 63.3% to 46.5% and maintaining a numerical advantage in all follow-up periods, while the A. xylosoxidans infection ranges from 13.7% to 39.3%. In 2016–2018, 50% of isolates were sensitive to carbapenems, in 2018 — 53.8% of isolates, in 2019–2020 — the activity of obtained isolates decreased to 37.5% and 30.7%, respectively. Conclusion: despite the dynamics of indicators and the sample size, the dynamics over 5 years maintained a group-wide proportion of microbiome species dominated primarily by Pseudomonas infection and A. xylosoxidans. In our follow-up, the activity of carbapenems in relation to A. xylosoxidans has almost halved. KEYWORDS: cystic fibrosis, Burkholderia cepacia complex, Achromobacter xylosoxidans, Pseudomonas aeruginosa, lethality, antibiotic resistance, carbapenems. FOR CITATION: Makhmutova V.R., Gembitskaya T.E., Chermensky A.G. et al. Achromobacter xylosoxidans infection and resistance monitoring in adult cystic fibrosis patients. Russian Medical Inquiry. 2021;5(7):462–467 (in Russ.). DOI: 10.32364/2587-6821-2021-5-7-462-467.

En Route to a Chiral Melanin: The Dynamic "From-Imprinted-to-Template" Supramolecular Role of Porphyrin Hetero-Aggregates During the Oxidative Polymerization of L-DOPA.

Chiral porphyrin hetero-aggregates, produced from meso-tetrakis(4-N-methylpyridyl) porphyrin H2T4 and copper(II) meso-tetrakis(4-sulfonatophenyl)porphyrin CuTPPS by an imprinting effect in the presence of L-3,4-dihydroxyphenylalanine (L-DOPA), are shown herein to serve as templates for the generation of chiral structures during the oxidative conversion of the amino acid to melanin. This remarkable phenomenon is suggested to involve the initial role of L-DOPA and related chiral intermediates like dopachrome as templates for the production of chiral porphyrin aggregates. When the entire chiral pool from DOPA is lost, chiral porphyrin hetero-aggregate would elicit axially chiral oligomer formation from 5,6-dihydroxyindole intermediates in the later stages of melanin synthesis. These results, if corroborated by further studies, may open unprecedented perspectives for efficient strategies of asymmetric melanin synthesis with potential biological and technological applications.

Stimulation of ABCB4/MDR3 ATPase activity requires an intact phosphatidylcholine lipid

ABCB4/MDR3 is located in the canalicular membrane of hepatocytes and translocates PC-lipids from the cytoplasmic to the extracellular leaflet. ABCB4 is an ATP-dependent transporter that reduces the harsh detergent effect of the bile salts by counteracting self-digestion. To do so, ABCB4 provides PC lipids for extraction into bile. PC lipids account for 40% of the entire pool of lipids in the canalicular membrane with an unknown distribution over both leaflets. Extracted PC lipids end up in so-called mixed micelles. Mixed micelles are composed of phospholipids, bile salts, and cholesterol. Ninety to ninety-five percent of the phospholipids are members of the PC family, but only a subset of mainly 16.0-18:1 PC and 16:0-18:2 PC variants are present. To elucidate whether ABCB4 is the key discriminator in this enrichment of specific PC lipids, we used in vitro studies to identify crucial determinants in substrate selection. We demonstrate that PC-lipid moieties alone are insufficient for stimulating ABCB4 ATPase activity, and that at least two acyl chains and the backbone itself are required for a productive interaction. The nature of the fatty acids, like length or saturation has a quantitative impact on the ATPase activity. Our data demonstrate a two-step enrichment and protective function of ABCB4 to mitigate the harsh detergent effect of the bile salts, because ABCB4 can translocate more than just the PC-lipid variants found in bile.

Identification of oligo-adenylated small RNAs in the parasite Entamoeba and a potential role for small RNA control

BackgroundThe RNA interference (RNAi) pathway is a gene regulation mechanism that utilizes small RNA (sRNA) and Argonaute (Ago) proteins to silence target genes. Our previous work identified a functional RNAi pathway in the protozoan parasite Entamoeba histolytica, including abundant 27 nt antisense sRNA populations which associate with EhAgo2–2 protein. However, there is lack of understanding about the sRNAs that are bound to two other EhAgos (EhAgo2–1 and 2–3), and the mechanism of sRNA regulation itself is unclear in this parasite. Therefore, identification of the entire pool of sRNA species and their sub-populations that associate with each individual EhAgo protein would be a major step forward.ResultsIn the present study, we sequenced sRNA libraries from both total RNAs and EhAgo bound RNAs. We identified a new population of 31 nt sRNAs that results from the addition of a non-templated 3–4 adenosine nucleotides at the 3′-end of the 27 nt sRNAs, indicating a non-templated RNA-tailing event in the parasite. The relative abundance of these two sRNA populations is linked to the efficacy of gene silencing for the target gene when parasites are transfected with an RNAi-trigger construct, indicating that non-templated sRNA-tailing likely play a role in sRNA regulation in this parasite. We found that both sRNA populations (27 nt and 31 nt) are present in the related parasite Entamoeba invadens, and are unchanged during the development. In sequencing the sRNAs associating with the three EhAgo proteins, we observed that despite distinct cellular localization, all three EhAgo sRNA libraries contain 27 nt sRNAs with 5′-polyphosphate (5′-polyP) structure and share a largely overlapping sRNA repertoire. In addition, our data showed that a fraction of 31 nt sRNAs associate with EhAgo2–2 but not with its mutant protein (C-terminal deletion), nor other two EhAgos, indicating a specific EhAgo site may be required for sRNA modification process in the parasite.ConclusionWe identified a new population of sRNA with non-templated oligo-adenylation modification, which is the first such observation amongst single celled protozoan parasites. Our sRNA sequencing libraries provide the first comprehensive sRNA dataset for all three Entamoeba Ago proteins, which can serve as a useful database for the amoeba community.

Abstract PO-076: Strategies to improve the reach of interventions to address inequities in cancer care: Results from a six-site initiative

Abstract Introduction: Large segments of the United States population do not receive quality cancer care due to pervasive and systemic inequities. Disparate cancer care is associated with increased morbidity and mortality. Multi-component, multi-level interventions can address inequities and improve care, but only if they reach populations of interest. Intervention studies often under-enroll populations of interest, despite having an adequate eligible pool. Procedures: The Alliance to Advance Patient-Centered Cancer Care supports six grantees across the US to implement diverse multi-component (e.g., access, symptom monitoring, wellness, survivorship), multi-level (e.g., patients, clinicians, caregivers) intervention programs with the shared goals of reducing disparities, increasing patient engagement, and improving the quality of cancer care. The Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework informs the evaluation efforts across the six sites. An important first step is to reach and enroll individuals who are most in need of cancer screening or access to cancer treatment. Target populations across sites include underrepresented minorities (e.g., Black and Latinx persons), those who speak English as a second language, and rural residents. Each participating site defined the target population(s) for their program. The sites used four key strategies to reach their target populations, which included: lay and clinical navigators, community advisory boards, data algorithms to conduct eligibility screening from the electronic health record, and dynamic community-based participatory research approaches. For years 2018-2019, we evaluated the demographic characteristics of participants recruited to program interventions compared to the overall demographic characteristics of each site’s pool of potentially eligible participants. Summary data: Of 4,692 potentially eligible participants, the six sites have enrolled 1,880 participants to date. Below we report the proportion of individuals with selected characteristics from the total enrolled: Black adults: 39% enrolled, (n=733), Latinx adults: 23% enrolled, (n=432), English as second language speakers: 19% enrolled, (n=357), and rural residents: 25% enrolled, (n=470). These proportions were similar or exceeded the proportions observed across the entire pool of eligible persons. Specifically, of 4,692 eligible persons across all sites, 35% were Black adults, 19% were Latinx adults, 15% spoke English as a second language, and 23% resided in rural areas. Conclusion: The Alliance to Advance Patient-Centered Cancer Care grantees have met or exceeded target enrollments from underserved groups to patient-centered intervention programs. Intentional strategies that include human resources, technology, and community engagement are needed and can be successful in improving access to high-quality cancer screening, treatment, and supportive care. Citation Format: Debra L. Barton, Bidisha Ghosh, Heidi A. Hamann, Sanja Percac-Lima, Adrian S. Dobs, Michelle J. Naughton, Roland P. Matthews, Sheryl Gabram-Mendola, Melissa A. Simon, Yvonne Bueno, Beverly Moy, Electra D. Paskett, Sankirtana M. Danner, Bingxin Chen, Robert J. Ploutz- Snyder, Christopher R. Friese. Strategies to improve the reach of interventions to address inequities in cancer care: Results from a six-site initiative [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-076.

On the microstructure and solidification behavior of new generation additively manufactured Al-Cu-Mg-Ag-Ti-B alloys

Abstract Laser powder bed fusion (LPBF) was used to horizontally print A205 ( Al — Cu — Mg — Ag — Ti — B ) metal powder. The samples have been cut in various directions to analyze their phases, grain morphology, size, crystallographic orientation, and distribution of elements via X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and X-ray energy dispersive spectroscopy (XEDS) in a transmission electron microscope (TEM). To monitor deformation behavior and strain distribution, several uniaxial tensile tests accompanied by digital image correlation (DIC) technique were carried out. The results showed that the as-built microstructure fully contains fine equiaxed grains with no strong preferential crystallographic orientation. The XEDS elemental maps confirmed the solute trapping phenomenon taking place during the LPBF. The stress-strain curves obtained by the uniaxial tensile testing revealed a quasi-isotropic behavior in terms of building direction; moreover, the DIC strain contour maps confirmed yield-point phenomenon and Luders bands propagation during uniaxial tensile testing. Finally, a time/temperature interdependence grain growth model was successfully applied based on no diffusion in solid and partial mixing in liquid through the entire melt pool.

Weak founder effects but significant spatial genetic imprint of recent contraction and expansion of European beech populations.

Understanding the ecological and evolutionary processes occurring during species range shifts is important in the current context of global change. Here, we investigate the interplay between recent expansion, gene flow and genetic drift, and their consequences for genetic diversity and structure at landscape and local scales in European beech (Fagus sylvatica L.) On Mont Ventoux, South-Eastern France, we located beech forest refugia at the time of the most recent population minimum, ~150 years ago, and sampled 71 populations (2042 trees) in both refugia and expanding populations over an area of 15,000 ha. We inferred patterns of gene flow and genetic structure using 12 microsatellite markers. We identified six plots as originating from planting, rather than natural establishment, mostly from local genetic material. Comparing genetic diversity and structure in refugia versus recent populations did not support the existence of founder effects: heterozygosity (He = 0.667) and allelic richness (Ar = 4.298) were similar, and FST was low (0.031 overall). Still, significant spatial evidence of colonization was detected, with He increasing along the expansion front, while genetic differentiation from the entire pool (βWT) decreased. Isolation by distance was found in refugia but not in recently expanding populations. Our study indicates that beech capacities for colonization and gene flow were sufficient to preserve genetic diversity despite recent forest contraction and expansion. Because beech has long distance pollen and seed dispersal, these results illustrate a 'best case scenario' for the maintenance of high genetic diversity and adaptive potential under climate-change-related range change.

Nickel and its isotopes in the Amazon Basin: The impact of the weathering regime and delivery to the oceans

Nickel (Ni) is an important bio-active element in the oceans, whose past marine abundance and isotope signature has the potential to be recorded in sediments. The interpretation of such a record in terms of earth system processes relies critically on understanding modern oceanic budgets. All oceanic Ni isotope data collected to date demonstrate that the oceanic dissolved pool is heavier than the largest known input, the dissolved load of rivers. Steady-state requires a light sink from the oceans that is of similar size to the inputs. The currently known sinks are much larger than the known inputs and are not isotopically light. At face value, this scenario requires an additional isotopically heavy source of Ni to the oceanic dissolved pool. Here, we present a comprehensive study of Ni and its isotopes, with auxiliary data, for multiple phases (dissolved (<0.45 μm), colloidal, truly-dissolved, total particulate and compartments within the particulate load) in multiple tributaries of the Amazon Basin across seasons, with the aim both of understanding the controls on riverine transport of Ni and its isotopes and of better characterising the riverine input to the oceans.Partitioning of Ni between the particulate and dissolved load is systematically related to river type, but in all rivers the dissolved load represents a substantial portion of the total. In the main Amazon, the dissolved load is 0.25–0.7 times that of the labile particulate load (i.e. that other than the Ni extracted with hydrofluoric acid). Ni isotope data for the dissolved phase of Amazon rivers show more variation than in a small published dataset for global rivers. There is systematic variability between river types, with black water rivers like the Negro being close to the upper continental crust at about +0.3‰ in δ60Ni, whereas white water rivers and the main Amazon stem have δ60Ni as high as +1.38‰. The main control is the variable sequestration of light Ni to secondary particulate phases, likely Fe-oxyhydroxides, both in soils and in the river itself. In addition to this first-order control, seasonal differences in Ni concentrations are best explained by the variable impact of a colloidal Ni phase from soils. Particulate phase Ni isotopes are uniformly much lighter than the dissolved phase, close to the upper continental crust. In most rivers the particulate load of Ni is sub-equally partitioned into a fraction that we identify as Fe-Mn oxides and a residual silicate fraction.The new data confirm that the dissolved load of rivers is an important source of Ni to the oceans, and that it is isotopically lighter than the oceanic dissolved pool. If the oceanic elemental mass imbalance is to be solved through the mobilisation of the suspended particulate load from continental margin sediments, it would require mobilisation of virtually the entire pool. However, such a solution to the elemental mass balance would lead to the input to the oceans of a large quantity of light Ni, which would make the isotope mass balance significantly worse.

Microbial Processing of Jellyfish Detritus in the Ocean.

When jellyfish blooms decay, sinking jellyfish detrital organic matter (jelly-OM), rich in proteins and characterized by a low C:N ratio, becomes a significant source of OM for marine microorganisms. Yet, the key players and the process of microbial jelly-OM degradation and the consequences for marine ecosystems remain unclear. We simulated the scenario potentially experienced by the coastal pelagic microbiome after the decay of a bloom of the cosmopolitan Aurelia aurita s.l. We show that about half of the jelly-OM is instantly available as dissolved organic matter and thus, exclusively and readily accessible to microbes. During a typical decay of an A. aurita bloom in the northern Adriatic Sea about 100 mg of jelly-OM L–1 becomes available, about 44 μmol L–1 as dissolved organic carbon (DOC), 13 μmol L–1 as total dissolved nitrogen, 11 μmol L–1 of total hydrolyzable dissolved amino acids (THDAA) and 0.6 μmol L–1 PO43–. The labile jelly-OM was degraded within 1.5 days (>98% of proteins, ∼70% of THDAA, 97% of dissolved free amino acids and the entire jelly-DOC pool) by a consortium of Pseudoalteromonas, Alteromonas, and Vibrio. These bacteria accounted for >90% of all metabolically active jelly-OM degraders, exhibiting high bacterial growth efficiencies. This implies that a major fraction of the detrital jelly-OM is rapidly incorporated into biomass by opportunistic bacteria. Microbial processing of jelly-OM resulted in the accumulation of tryptophan, dissolved combined amino acids and inorganic nutrients, with possible implications for biogeochemical cycles.

A phase-field simulation of columnar-to-equiaxed transition in the entire laser welding molten pool

In order to simulate the columnar-to-equiaxed transition (CET) in the entire molten pool of Al–Cu alloy laser welding, a phase-field model was established by considering crystalline orientations and heterogeneous nucleation. Simulation results revealed that crystals initialized as planar ones from the molten pool edge and were then transformed into columnar dendrites during the solidification process. It was found that dendrites grew toward the center of the fusion zone irrespective of their crystalline orientations. Equiaxed grains grew ahead of columnar dendrites. They gradually formed a belt ahead of columnar dendrites and stopped columnar dendrites from growing. The highest number of equiaxed grains was found at the top edge of the cross-section of the molten pool due to the fastest pulling velocity. The variation of undercooling in the molten pool was analyzed to investigate CET during the solidification process. Heterogeneous nuclei were formed throughout the solidification process. They melted during the early stage of the solidification process and started to grow when the undercooling ahead of columnar dendrites was large enough. With the prolonged solidification, the number of heterogeneous nuclei gradually increased and the size of equiaxed grains decreased. Experimental results were consistent with simulations.