480 research outputs found

    Effects of seed predators of different body size on seed mortality in Bornean logged gorest

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    Background The Janzen-Connell hypothesis proposes that seed and seedling enemies play a major role in maintaining high levels of tree diversity in tropical forests. However, human disturbance may alter guilds of seed predators including their body size distribution. These changes have the potential to affect seedling survival in logged forest and may alter forest composition and diversity. Methodology/Principal Findings We manipulated seed density in plots beneath con- and heterospecific adult trees within a logged forest and excluded vertebrate predators of different body sizes using cages. We show that small and large-bodied predators differed in their effect on con- and heterospecific seedling mortality. In combination small and large-bodied predators dramatically decreased both con- and heterospecific seedling survival. In contrast, when larger-bodied predators were excluded small-bodied predators reduced conspecific seed survival leaving seeds coming from the distant tree of a different species. Conclusions/Significance Our results suggest that seed survival is affected differently by vertebrate predators according to their body size. Therefore, changes in the body size structure of the seed predator community in logged forests may change patterns of seed mortality and potentially affect recruitment and community composition

    Differential growth responses in seedlings of ten species of Dipterocarpaceae to experimental shading and defoliation

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    The responses of plants to shade and foliar herbivory jointly affect growth rates and community assembly. We grew 600 seedlings of ten species of the economically important Dipterocarpaceae in experimental gradients of shading (0.3-47.0% of full sunlight) and defoliation (0, 25%, 50% or 75% of leaf area removed). We assessed stem diameters initially, after 2 and 4 mo, and calculated relative growth rates (RGR) with a linear model. Shading interacted with defoliation, reducing RGR by 21.6% in shaded conditions and 8.9% in well-lit conditions. We tested three hypotheses for interspecific trade-offs in growth responses to shading and defoliation. They could be positively related, because both reduce a plant's access to carbon, or inversely related because of trade-offs between herbivore resistance and tolerance. We observed, however, that species varied in their response to shading, but not defoliation, precluding an interspecific trade-off and suggesting that plants tolerate shade and herbivory with differing strategies. Shading most strongly reduced the growth of species with less-dense wood and larger seeds. The strong and variable growth responses to shade, contrasted with the weak and uniform responses to defoliation, suggest that variation in light availability more strongly affects the growth of tropical tree seedlings, and thus community assembly, than does variation in herbivor

    Novel transcriptomic panel identifies histologically active eosinophilic oesophagitis.

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    Eosinophilic oesophagitis (EoE) is characterised by symptoms of esophageal dysfunction and oesinophil tissue infiltration. The EoE Diagnostic Panel (EDP) can distinguish between active and non-active EoE using a set of 77 genes. Recently, the existence of distinct EoE variants featuring symptoms similar to EoE, such as oesophageal dysfunction but lacking eosinophil infiltration, had been determined. We used oesophageal biopsies from patients with histologically active (n=10) and non-active EoE (n=9) as well as from healthy oesophageal controls (n=5) participating in the Swiss Eosinophilic Esophagitis Cohort Study (SEECS) and analysed the gene expression profile in these biopsies by total RNA-sequencing (RNA-seq). Moreover, we employed the publicly accessible RNA-seq dataset (series GSE148381) as reported by Greuter et al, encompassing a comprehensive genomic profile of patients presenting with EoE variants. A novel, diagnostic gene expression panel that can effectively distinguish patients with histologically active conventional EoE from patients with EoE in histological remission and control individuals, and from three newly discovered EoE variants was identified. Histologically Active EoE Diagnostic Panel (HAEDP) consists of 53 genes that were identified based on differential expression between histologically active EoE, histological remission and controls (p≤0.05). By combining the HAEDP with EDP, we expanded our knowledge about factors that may contribute to the inflammation in EoE and improved our understanding of the underlying mechanisms of the disease. Conversely, we suggested a compact group of genes common to both HAEDP and EDP to create a reliable diagnostic tool that might enhance the accuracy of EoE diagnosis. We identified a novel set of 53 dysregulated genes that are closely associated with the histological inflammatory activity of EoE. In combination with EDP, our new panel might be a valuable tool for the accurate diagnosis of patients with EoE as well as for monitoring their disease course

    Synthesizing a σ^z\hat{\sigma}_z spin-dependent force for optical, metastable, and ground state trapped-ion qubits

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    A single bichromatic field near-resonant to a qubit transition is typically used for σ^x\hat{\sigma}_x or σ^y\hat{\sigma}_y M{\o}lmer-S{\o}rensen type interactions in trapped ion systems. Using this field configuration, we present a novel scheme to synthesize a σ^z\hat{\sigma}_z spin-dependent force instead; this basis change merely requires adjusting the beat-note frequency of the bichromatic field. We implement this scheme with a laser near-resonant to a quadrupole transition in 88^{88}Sr+^+. We characterise its robustness to optical phase and qubit frequency offsets and demonstrate its versatility by entangling optical, metastable, and ground state qubits.Comment: O. B\u{a}z\u{a}van and S. Saner contributed equally to this wor

    Glutathione-S-transferase subtypes α and π as a tool to predict and monitor graft failure or regeneration in a pilot study of living donor liver transplantation

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    <p>Abstract</p> <p>Objective</p> <p>Glutathione-S-Transferase (GST) subtype α and π are differentially expressed in adult liver tissue. Objective of the study was if GST α and p may serve as predictive markers for liver surgery, especially transplantations.</p> <p>Methods</p> <p>13 patients receiving living donor liver transplantation (LDLT) and their corresponding donors were analyzed for standard serum parameters (ALT, AST, gGT, bilirubin) as well as GST-α and -π before LDLT and daily for 10 days after LDLT. Patients (R) and donors (D) were grouped according to graft loss (R1/D1) or positive outcome (R2/D2) and above named serum parameters were compared between the groups.</p> <p>Results</p> <p>R1 showed significantly increased GST-α and significantly lower GST-π levels than R2 patients or the donors. There was a positive correlation between GST-α and ALT, AST as well as bilirubin and a negative correlation to γGT. However, γGT correlated positively with GST-π. Graft failure was associated with combined low GST-π levels in donors and their recipients before living donor liver transplantation.</p> <p>Conclusion</p> <p>Our data suggest that high GST-α serum levels reflect ongoing liver damage while GST-P indicates the capacity and process of liver regeneration. Additionally, GST-π may be useful as marker for optimizing donor and recipient pairs in living donor liver transplantation.</p

    A Rare Case of Propofol-Induced Acute Liver Failure and Literature Review

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    The incidence of drug-induced acute liver failure is increasing. A number of drugs can inhibit mitochondrial functions, alter β-oxidation and cause accumulation of free fatty acids within the hepatocytes. This may result in hepatic steatosis, cell death and liver injury. In our case, propofol, an anesthetic drug commonly used in adults and children, is suspected to have induced disturbance of the mitochondrial respiratory chain, which in consequence led to insufficient energy supply and finally liver failure. We report the case of a 35-year-old Caucasian woman with acute liver failure after anesthesia for stripping of varicose veins. Liver histology, imaging and laboratory data indicate drug-induced acute liver failure, presumably due to propofol. Hepatocyte death and microvesicular fatty degeneration of 90% of the liver parenchyma were observed before treatment with steroids. Six months later, a second biopsy was performed, which revealed only minimal steatosis and minimal periportal hepatitis. We suggest that propofol led to impaired fatty acid oxidation possibly due to a genetic susceptibility. This caused free fatty acid accumulation within hepatocytes, which presented as hepatocellular fatty degeneration and cell death. Large scale hepatocyte death was followed by impaired liver function and, consecutively, progressed to acute liver failure

    Breaking the entangling gate speed limit for trapped-ion qubits using a phase-stable standing wave

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    All laser-driven entangling operations for trapped-ion qubits have hitherto been performed without control of the optical phase of the light field, which precludes independent tuning of the carrier and motional coupling. By placing 88^{88}Sr+^+ ions in a λ=674\lambda=674 nm standing wave, whose relative position is controlled to λ/100\approx\lambda/100, we suppress the carrier coupling by a factor of 1818, while coherently enhancing the spin-motion coupling. We experimentally demonstrate that the off-resonant carrier coupling imposes a speed limit for conventional traveling-wave M{\o}lmer-S{\o}rensen gates; we use the standing wave to surpass this limit and achieve a gate duration of $15\ \mu$s, restricted by the available laser power.Comment: S. Saner and O. B\u{a}z\u{a}van contributed equally to this wor

    Evidence for the protein leverage hypothesis in preschool children prone to obesity.

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    BACKGROUND & AIMS The protein leverage hypothesis (PLH) proposed that strict regulation of protein intake drives energy overconsumption and obesity when diets are diluted by fat and/or carbohydrates. Evidence about the PLH has been found in adults, while studies in children are limited. Thus, we aimed to test the PLH by assessing the role of dietary protein on macronutrients, energy intake, and obesity risk using data from preschool children followed for 1.3 years. METHODS 553 preschool children aged 2-6 years from the 'Healthy Start' project were included. EXPOSURES The proportion of energy intake from protein, fat, and carbohydrates collected from a 4-day dietary record. OUTCOMES Energy intake, BMI z-score, fat mass (FM) %, waist- (WHtR) and hip-height ratio (HHtR). Power function analysis was used to test the leverage of protein on energy intake. Mixture models were used to explore interactive associations of macronutrient composition on all these outcomes, with results visualized as response surfaces on the nutritional geometry. RESULTS Evidence for the PLH was confirmed in preschool children. The distribution of protein intake (% of MJ, IQR: 3.2) varied substantially less than for carbohydrate (IQR: 5.7) or fat (IQR: 6.3) intakes, suggesting protein intake is most tightly regulated. Absolute energy intake varied inversely with dietary percentage energy from protein (L = -0.14, 95% CI: -0.25, -0.04). Compared to children with high fat or carbohydrate intakes, children with high dietary protein intake (>20% of MJ) had a greater decrease in WHtR and HHtR over the 1.3-year follow-up, offering evidence for the PLH in prospective analysis. But no association was observed between macronutrient distribution and changes in BMI z-score or FM%. CONCLUSIONS In this study in preschool children, protein intake was the most tightly regulated macronutrient, and energy intake was an inverse function of dietary protein concentration, indicating the evidence for protein leverage. Increases in WHtR and HHtR were principally associated with the dietary protein dilution, supporting the PLH. These findings highlight the importance of protein in children's diets, which seems to have significant implications for childhood obesity risk and overall health
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