142 research outputs found

    Understanding the Heteroatom Effect on the Ullmann Copper-Catalyzed Cross-Coupling of X-Arylation (X = NH, O, S) Mechanism

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    Density Functional Theory (DFT) calculations have been carried out in order to unravel the governing reaction mechanism in copper-catalyzed cross-coupling Ullmann type reactions between iodobenzene (1, PhI) and aniline (2-NH, PhNH2), phenol (2-O, PhOH) and thiophenol (2-S, PhSH) with phenanthroline (phen) as the ancillary ligand. Four different pathways for the mechanism were considered namely Oxidative Addition–Reductive Elimination (OA-RE), σ-bond Metathesis (MET), Single Electron Transfer (SET), and Halogen Atom Transfer (HAT). Our results suggest that the OA-RE route, involving CuIII intermediates, is the energetically most favorable pathway for all the systems considered. Interestingly, the rate-determining step is the oxidative addition of the phenyl iodide to the metal center regardless of the nature of the heteroatom. The computed energy barriers in OA increase in the order O < S < NH. Using the Activation Strain Model (ASM) of chemical reactivity, it was found that the strain energy associated with the bending of the copper(I) complex controls the observed reactivity

    Food intake regulating-neuropeptides are expressed and regulated through pregnancy and following food restriction in rat placenta

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    Background Neuropeptide Y (NPY), agouti related peptide (AgRP), cocaine and amphetamine-regulated transcript (CART) and melanocortins, the products of the proopiomelanocortin (POMC), are hypothalamic peptides involved in feeding regulation and energy homeostasis. Recent evidence has demonstrated their expression in rat and human placenta. Methods In the current study, we have investigated the expression of those neuropeptides in the rat placenta by real-time PCR using a model of maternal food restriction. Results Our results showed that placental-derived neuropeptides were regulated through pregnancy and following food restriction. Conclusion These data could indicate that placental-derived neuropeptides represent a local regulatory circuit that may fine-tune control of energy balance during pregnancyThis work has been supported by grants from Xunta de Galicia (ML: GRC2006/66), Fondo Investigationes Sanitarias (ML: PI061700), Ministerio de Educacion y Ciencia (CD: BFU2005), MĂștua Madrileña (CD and ML) and European Union (CD: LSHM-CT-2003-503041)S

    Optimal Design of Multilayer Fog Collectors.

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    The growing concerns over desertification have spurred research into technologies aimed at acquiring water from nontraditional sources such as dew, fog, and water vapor. Some of the most promising developments have focused on improving designs to collect water from fog. However, the absence of a shared framework to predict, measure, and compare the water collection efficiencies of new prototypes is becoming a major obstacle to progress in the field. We address this problem by providing a general theory to design efficient fog collectors as well as a concrete experimental protocol to furnish our theory with all the necessary parameters to quantify the effective water collection efficiency. We show in particular that multilayer collectors are required for high fog collection efficiency and that all efficient designs are found within a narrow range of mesh porosity. We support our conclusions with measurements on simple multilayer harp collectors.EPSR

    Maternal Serum Meteorin Levels and the Risk of Preeclampsia

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    BACKGROUND: Meteorin (METRN) is a recently described neutrophic factor with angiogenic properties. This is a nested case-control study in a longitudinal cohort study that describes the serum profile of METRN during different periods of gestation in healthy and preeclamptic pregnant women. Moreover, we explore the possible application of METRN as a biomarker. METHODS AND FINDINGS: Serum METRN was measured by ELISA in a longitudinal prospective cohort study in 37 healthy pregnant women, 16 mild preeclamptic women, and 20 healthy non-pregnant women during the menstrual cycle with the aim of assessing serum METRN levels and its correlations with other metabolic parameters. Immunostaining for METRN protein was performed in placenta. A multivariate logistic regression model was proposed and a classifier model was formulated for predicting preeclampsia in early and middle pregnancy. The performance in classification was evaluated using measures such as sensitivity, specificity, and the receiver operating characteristic (ROC) curve. In healthy pregnant women, serum METRN levels were significantly elevated in early pregnancy compared to middle and late pregnancy. METRN levels are significantly lower only in early pregnancy in preeclamptic women when compared to healthy pregnant women. Decision trees that did not include METRN levels in the first trimester had a reduced sensitivity of 56% in the detection of preeclamptic women, compared to a sensitivity of 69% when METRN was included. CONCLUSIONS: The joint measurements of circulating METRN levels in the first trimester and systolic blood pressure and weight in the second trimester significantly increase the probabilities of predicting preeclampsia

    Multiple myeloma and SARS-CoV-2 infection : clinical characteristics and prognostic factors of inpatient mortality

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    There is limited information on the characteristics, prognostic factors, and outcomes of patients with multiple myeloma (MM) hospitalized with COVID-19. This retrospective case series investigated 167 patients reported from 73 hospitals within the Spanish Myeloma Collaborative Group network in March and April, 2020. Outcomes were compared with 167 randomly selected, contemporary, age-/sex-matched noncancer patients with COVID-19 admitted at six participating hospitals. Among MM and noncancer patients, median age was 71 years, and 57% of patients were male; 75 and 77% of patients, respectively, had at least one comorbidity. COVID-19 clinical severity was moderate-severe in 77 and 89% of patients and critical in 8 and 4%, respectively. Supplemental oxygen was required by 47 and 55% of MM and noncancer patients, respectively, and 21%/9% vs 8%/6% required noninvasive/invasive ventilation. Inpatient mortality was 34 and 23% in MM and noncancer patients, respectively. Among MM patients, inpatient mortality was 41% in males, 42% in patients aged >65 years, 49% in patients with active/progressive MM at hospitalization, and 59% in patients with comorbid renal disease at hospitalization, which were independent prognostic factors on adjusted multivariate analysis. This case series demonstrates the increased risk and identifies predictors of inpatient mortality among MM patients hospitalized with COVID-19

    Surrogate indices of insulin resistance using the Matsuda index as reference in adult men—a computational approach

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    BackgroundOverweight and obesity, high blood pressure, hyperglycemia, hyperlipidemia, and insulin resistance (IR) are strongly associated with non-communicable diseases (NCDs), including type 2 diabetes, cardiovascular disease, stroke, and cancer. Different surrogate indices of IR are derived and validated with the euglycemic–hyperinsulinemic clamp (EHC) test. Thus, using a computational approach to predict IR with Matsuda index as reference, this study aimed to determine the optimal cutoff value and diagnosis accuracy for surrogate indices in non-diabetic young adult men.MethodsA cross-sectional descriptive study was carried out with 93 young men (ages 18–31). Serum levels of glucose and insulin were analyzed in the fasting state and during an oral glucose tolerance test (OGTT). Additionally, clinical, biochemical, hormonal, and anthropometric characteristics and body composition (DEXA) were determined. The computational approach to evaluate the IR diagnostic accuracy and cutoff value using difference parameters was examined, as well as other statistical tools to make the output robust.ResultsThe highest sensitivity and specificity at the optimal cutoff value, respectively, were established for the Homeostasis model assessment of insulin resistance index (HOMA-IR) (0.91; 0.98; 3.40), the Quantitative insulin sensitivity check index (QUICKI) (0.98; 0.96; 0.33), the triglyceride-glucose (TyG)-waist circumference index (TyG-WC) (1.00; 1.00; 427.77), the TyG-body mass index (TyG-BMI) (1.00; 1.00; 132.44), TyG-waist-to-height ratio (TyG-WHtR) (0.98; 1.00; 2.48), waist-to-height ratio (WHtR) (1.00; 1.00; 0.53), waist circumference (WC) (1.00; 1.00; 92.63), body mass index (BMI) (1.00; 1.00; 28.69), total body fat percentage (TFM) (%) (1.00; 1.00; 31.07), android fat (AF) (%) (1.00; 0.98; 40.33), lipid accumulation product (LAP) (0.84; 1.00; 45.49), leptin (0.91; 1.00; 16.08), leptin/adiponectin ratio (LAR) (0.84; 1.00; 1.17), and fasting insulin (0.91; 0.98; 16.01).ConclusionsThe computational approach was used to determine the diagnosis accuracy and the optimal cutoff value for IR to be used in preventive healthcare

    Efficient Photodynamic Therapy against Gram-Positive and Gram-Negative Bacteria Using THPTS, a Cationic Photosensitizer Excited by Infrared Wavelength

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    The worldwide rise in the rates of antibiotic resistance of bacteria underlines the need for alternative antibacterial agents. A promising approach to kill antibiotic-resistant bacteria uses light in combination with a photosensitizer to induce a phototoxic reaction. Concentrations of 1, 10 and 100”M of tetrahydroporphyrin-tetratosylat (THPTS) and different incubation times (30, 90 and 180min) were used to measure photodynamic efficiency against two Gram-positive strains of S.aureus (MSSA and MRSA), and two Gram-negative strains of E.coli and P.aeruginosa. We found that phototoxicity of the drug is independent of the antibiotic resistance pattern when incubated in PBS for the investigated strains. Also, an incubation with 100”M THPTS followed by illumination, yielded a 6lg (≄99.999%) decrease in the viable numbers of all bacteria strains tested, indicating that the THPTS drug has a high degree of photodynamic inactivation. We then modulated incubation time, photosensitizer concentration and monitored the effect of serum on the THPTS activity. In doing so, we established the conditions to obtain the strongest bactericidal effect. Our results suggest that this new and highly pure synthetic compound should improve the efficiency of photodynamic therapy against multiresistant bacteria and has a significant potential for clinical applications in the treatment of nosocomial infections

    Expression and Localization of CLC Chloride Transport Proteins in the Avian Retina

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    Members of the ubiquitously expressed CLC protein family of chloride channels and transporters play important roles in regulating cellular chloride and pH. The CLCs that function as Cl−/H+ antiporters, ClCs 3–7, are essential in particular for the acidification of endosomal compartments and protein degradation. These proteins are broadly expressed in the nervous system, and mutations that disrupt their expression are responsible for several human genetic diseases. Furthermore, knock-out of ClC3 and ClC7 in the mouse result in the degeneration of the hippocampus and the retina. Despite this evidence of their importance in retinal function, the expression patterns of different CLC transporters in different retinal cell types are as yet undescribed. Previous work in our lab has shown that in chicken amacrine cells, internal Cl− can be dynamic. To determine whether CLCs have the potential to participate, we used PCR and immunohistochemical techniques to examine CLC transporter expression in the chicken retina. We observed a high level of variation in the retinal expression levels and patterns among the different CLC proteins examined. These findings, which represent the first systematic investigation of CLC transporter expression in the retina, support diverse functions for the different CLCs in this tissue
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