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Growth in the immediate postnatal period for extremely low birth weight (ELBW, birth weight < 1000 g) infants is an important topic in neonatal medicine. The goal is to ensure adequate postnatal growth and to minimize complications resulting from suboptimal growth. Past efforts have focused on postnatal nutrition as well as on minimizing comorbidities. It has not been systematically assessed whether antenatal factors play a role in postnatal growth. In this report, we conducted a retrospective study on 91 maternal–neonatal pairs. We prospectively collected maternal and neonatal demographic data, neonatal nutrition in the first 7 days of life and after enteral nutrition is fully established, comorbidity data, as well as weight data from birth to 50 weeks corrected gestational age. We developed a linear mixed-effects model to examine the role of placental insufficiency, as defined by fetal Doppler studies, in postnatal weight z-score trajectory over time in the ELBW population. We relied on Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) for model selection. Interestingly, the selected model included a quadratic term of time and a placental insufficiency-by-time interaction term. In a covariate analysis, AIC and BIC both favored a model that included calories intake in the first 7 days of life and the total duration of antibiotics as fixed-effects, but not their interaction terms with time. Overall, we demonstrated for the first time that placental insufficiency, an antenatal factor, is a major determinant of postnatal weight trajectory in the ELBW population. Prospective studies are warranted to confirm our findings.
Depression is a clinically heterogeneous disorder. Previous large-scale genetic studies of depression have explored genetic risk factors of depression case–control status or aggregated sums of depressive symptoms, ignoring possible clinical or genetic heterogeneity.
We analyse data from 148 752 subjects of white British ancestry in the UK Biobank who completed nine items of a self-rated measure of current depressive symptoms: the Patient Health Questionnaire (PHQ-9). Genome-Wide Association analyses were conducted for nine symptoms and two composite measures. LD Score Regression was used to calculate SNP-based heritability (h2SNP) and genetic correlations (rg) across symptoms and to investigate genetic correlations with 25 external phenotypes. Genomic structural equation modelling was used to test the genetic factor structure across the nine symptoms.
We identified nine genome-wide significant genomic loci (8 novel), with no overlap in loci across symptoms. h2SNP ranged from 6% (concentration problems) to 9% (appetite changes). Genetic correlations ranged from 0.54 to 0.96 (all p < 1.39 × 10−3) with 30 of 36 correlations being significantly smaller than one. A two-factor model provided the best fit to the genetic covariance matrix, with factors representing ‘psychological’ and ‘somatic’ symptoms. The genetic correlations with external phenotypes showed large variation across the nine symptoms.
Patterns of SNP associations and genetic correlations differ across the nine symptoms, suggesting that current depressive symptoms are genetically heterogeneous. Our study highlights the value of symptom-level analyses in understanding the genetic architecture of a psychiatric trait. Future studies should investigate whether genetic heterogeneity is recapitulated in clinical symptoms of major depression.
Background. Frequency and quantity of alcohol consumption are metrics commonly used to measure alcohol consumption behaviors. Epidemiological studies indicate that these alcohol consumption measures are differentially associated with (mental) health outcomes and socioeconomic status (SES). The current study aims to elucidate to what extent genetic risk factors are shared between frequency and quantity of alcohol consumption, and how these alcohol consumption measures are genetically associated with four broad phenotypic categories: (i) SES; (ii) substance use disorders; (iii) other psychiatric disorders; and (iv) psychological/personality traits.
Methods. Genome-Wide Association analyses were conducted to test genetic associations with alcohol consumption frequency (N = 438 308) and alcohol consumption quantity (N = 307 098 regular alcohol drinkers) within UK Biobank. For the other phenotypes, we used genome-wide association studies summary statistics. Genetic correlations (rg) between the alcohol measures and other phenotypes were estimated using LD score regression.
Results. We found a substantial genetic correlation between the frequency and quantity of alcohol consumption (rg = 0.52). Nevertheless, both measures consistently showed opposite genetic correlations with SES traits, and many substance use, psychiatric, and psychological/personality traits. High alcohol consumption frequency was genetically associated with high SES and low risk of substance use disorders and other psychiatric disorders, whereas the opposite applies for high alcohol consumption quantity.
Conclusions. Although the frequency and quantity of alcohol consumption show substantial genetic overlap, they consistently show opposite patterns of genetic associations with SES-related phenotypes. Future studies should carefully consider the potential influence of SES on the shared genetic etiology between alcohol and adverse (mental) health outcomes.
A point-prevalence study of antimicrobial use among inpatients at 5 public hospitals in Sri Lanka revealed that 54.6% were receiving antimicrobials: 43.1% in medical wards, 68.0% in surgical wards, and 97.6% in intensive care wards. Amoxicillin-clavulanate was most commonly used for major indications. Among patients receiving antimicrobials, 31.0% received potentially inappropriate therapy.
We report the utility of whole-genome sequencing (WGS) conducted in a clinically relevant time frame (ie, sufficient for guiding management decision), in managing a Streptococcus pyogenes outbreak, and present a comparison of its performance with emm typing.
A 2,000-bed tertiary-care psychiatric hospital.
Active surveillance was conducted to identify new cases of S. pyogenes. WGS guided targeted epidemiological investigations, and infection control measures were implemented. Single-nucleotide polymorphism (SNP)–based genome phylogeny, emm typing, and multilocus sequence typing (MLST) were performed. We compared the ability of WGS and emm typing to correctly identify person-to-person transmission and to guide the management of the outbreak.
The study included 204 patients and 152 staff. We identified 35 patients and 2 staff members with S. pyogenes. WGS revealed polyclonal S. pyogenes infections with 3 genetically distinct phylogenetic clusters (C1–C3). Cluster C1 isolates were all emm type 4, sequence type 915 and had pairwise SNP differences of 0–5, which suggested recent person-to-person transmissions. Epidemiological investigation revealed that cluster C1 was mediated by dermal colonization and transmission of S. pyogenes in a male residential ward. Clusters C2 and C3 were genomically diverse, with pairwise SNP differences of 21–45 and 26–58, and emm 11 and mostly emm120, respectively. Clusters C2 and C3, which may have been considered person-to-person transmissions by emm typing, were shown by WGS to be unlikely by integrating pairwise SNP differences with epidemiology.
WGS had higher resolution than emm typing in identifying clusters with recent and ongoing person-to-person transmissions, which allowed implementation of targeted intervention to control the outbreak.
Recent progress in graphite target production for sub-milligram environmental samples in our facility is presented. We describe an optimized hydrolysis procedure now routinely used for the preparation of CO2 from inorganic samples, a new high-vacuum line dedicated to small sample processing (combining sample distillation and graphitization units), as well as a modified graphitization procedure. Although measurements of graphite targets as small as 35 μg C have been achieved, system background and measurement uncertainties increase significantly below 150 μg C. As target lifetime can become critically short for targets <150 μg C, the facility currently only processes inorganic samples down to 150 μg C. All radiocarbon measurements are made at the Scottish Universities Environmental Research Centre (SUERC) accelerator mass spectrometry (AMS) facility. Sample processing and analysis are labor-intensive, taking approximately 3 times longer than samples ≥ 500 μg C. The technical details of the new system, graphitization yield, fractionation introduced during the process, and the system blank are discussed in detail.
Recent progress in preparation/combustion of submilligram organic samples at our laboratories is presented. Routine methods had to be modified/refined to achieve acceptable and consistent procedural blanks for organic samples smaller than 1000 μg C. A description of the process leading to a modified combustion method for smaller organic samples is given in detail. In addition to analyzing different background materials, the influence of different chemical reagents on the overall radiocarbon background level was investigated, such as carbon contamination arising from copper oxide of different purities and from different suppliers. Using the modified combustion method, small amounts of background materials and known-age standard IAEA-C5 were individually combusted to CO2. Below 1000 μg C, organic background levels follow an inverse mass dependency when combusted with the modified method, increasing from 0.13 ± 0.05 pMC up to 1.20 ± 0.04 pMC for 80 μg C. Results for a given carbon mass were lower for combustion of etched Iceland spar calcite mineral, indicating that part of the observed background of bituminous coal was probably introduced by handling the material in atmosphere prior to combustion. Using the modified combustion method, the background-corrected activity of IAEA-C5 agreed to within 2 σ of the consensus value of 23.05 pMC down to a sample mass of 55 μg C.
Calibration (using CALIBomb) of radiocarbon measurements made on the enamel of human teeth from people born during the nuclear era typically produce 2 possible age ranges that potentially reflect the period of tooth formation. These ranges correspond to periods before and after the 1963 atmospheric 14C maximum. Further measurements made on the collagen component of the combined dentine and cementum from the roots of the same teeth enable the appropriate age range to be selected. Using this range and the formation times for individual teeth, we estimated the year of birth of the individuals and compared these to the known dates of birth. The results were relatively accurate and confirmed those of a previous study by another research group. The present study demonstrates that it is possible to produce a good estimate of the year of birth from a single tooth.
This article presents new radiocarbon ages for the lavas, pyroclastic flow, and lahar deposits that originated from the Fugendake and Mayuyama volcanoes of the Younger Unzen Volcano, SW Japan. Nine charcoal samples were collected from the lavas and pyroclastic flow deposits, and 17 soil samples from the underlying volcanic-related products. This data set, together with previously published ages (thermoluminescence, K-Ar, fission track, and 14C), yielded new information about the timing of Late Pleistocene eruptions and an improved understanding of the evolution of the Fugendake and Mayuyama volcanoes. Fugendake Volcano started to build within the scar of Myokendake around 29 cal ka BP, and its eruption products spread over the flank of Myokendake. The remarkable eruptions of Fugendake Volcano included the lava and pyroclastic flow deposits around 22, 17, 12, and 4.5 cal ka BP. Subsequent historical eruptions occurred in AD 1663, 1792, and 1991–1995. Developed on the eastern extension of Fugendake Volcano, Mayuyama Volcano was active during the building stage of Fugendake at 4.5 cal ka BP. This study also identified a pumice eruption at ∼10 ka and 2 volcanic-related lahar deposits around 1.6 and 0.7 ka, which need to be addressed in future research.
We develop a theoretical model for terahertz (THz) radiation generation, when an intense short laser pulse (ω1, k1) is mixed with its frequency shifted second harmonic (ω2, k2), where ω2 = 2ω1 + ωT and ωT is in the THz range in the plasma. The lasers exert a ponderomotive force on the electrons and drive density perturbations at (2ω1, 2k1) and (ω2 − ω1, k2 − k1). These density perturbations couple with the oscillatory velocities of the electron due to the lasers and produce a nonlinear current at (ω2 − 2ω1, k2 − 2k1). This current acts as an antenna to produce the THz radiation. The THz power depends upon the square of plasma density and
, where I1 and I2 are the intensities of fundamental and second harmonic laser. The radiation is mainly along the forward direction. Two-dimensional particle-in-cell simulations are used to study the near-field radiation properties.
The goal of this research is to synthesize novel linear and hyperbranched polythiophene derivatives containing diketopyrrolopyrrole (DPP) as linking groups, and to investigate thermal, optical, electrochemical, and photovoltaic properties of those derivatives. Polymers with high regioregularity were synthesized via the Universal Grignard metathesis polymerization. Those linear or hyperbranched polythiophenes containing DPP bridging moieties showed higher molecular weights and better thermal stability compared with normal P3HT. The UV-vis absorption spectra of the DPP-containing polymers are similar to that of P3HT in film state, while they show distinct attenuation in fluorescent emission. Finally, all polymers were blended with PC61BM and used as active layers for fabrication of inverted solar devices. The devices based on those DPP-containing polythiophenes revealed the open-circuit voltage (VOC) of 0.55–0.58 V, the short-circuit current (JSC) of 8.62–16.21 mA/cm2, the fill factor (FF) of 36–41%, and the power conversion efficiency (PCE) of 1.73–3.74%.
We like to report a novel conductive film containing graphene-silver nanohybrids from the process of solution coating and annealing at low-temperature for melting silver nanoparticles (AgNPs) into interconnected Ag matrice on surface. The fabrication required the assistance of a home-made polymeric dispersant, poly(oxyethylene)-segmented imide (POE-imide), for homogenize the AgNPs and graphene in hybridized form. The intermediate dispersion of AgNPs at 10–25 nm diameter on the surface of 2D-graphene were characterized and subsequently subjected to solution coating into thin films. Under the annealing temperature as low as 160 °C, the films exhibited a high electric conductivity or low sheet resistance at 2.4×10–1 Ω/sq (equivalent to 7.9×104 S/cm). It is noteworthy that the significant point of low-temperature annealing at 160–170 °C that is attributed to the fast deterioration and degradation of the POE-imide organics kinetically before the AgNP coalescence and melting. Furthermore, the comparisons of using silicate clays and carbon nanotubes in replacing the 2D graphene for hybridizing Ag had revealed the different morphologies in Ag networks. The findings of using the polymeric dispersion for synthesizing nanohybrids may open up a new avenue for making films with integrated properties of flexibility, transparency and high conductivity for a host of electronic applications.
The magnetic reconnection (MR) configuration was constructed by using two approaching laser-produced plasma bubbles. The characteristics of the MR current sheet were investigated. The driving energy of the laser pulse affects the type of the current sheet. The experiments present “Y-type” and “X-type” current sheets for larger and smaller driving energy, respectively. The energetic electrons were found to be well-collimated. The formation and ejection of plasmoid from the “Y-type” current sheet was expected to enhance the number of accelerated electrons.
GB virus C (GBV-C) is frequently identified in patients co-infected with human immunodeficiency virus type 1 (HIV-1) due to the similar transmission routes. However, it remains unclear how these two viruses interact with each other and how one virus affects the replication of the other in the human body. In this study, we performed a case-control study to determine whether GBV-C viraemia could prevent the acquisition of HIV-1 infection, and a cohort study to determine the prevalence, genotypic characteristics and incidence of GBV-C infection in men who have sex with men (MSM) populations in Beijing, China. The prevalence of GBV-C infection in HIV-1-negative subjects was similar to that in HIV-1-positive subjects. Before HIV-1 acquisition, the prevalence of GBV-C was 17·7%, which increased to 27·2% at the acute stage and to 34% at the chronic stage. Genotype 3 was the major genotype of GBV-C in both groups. A significantly positive correlation was observed between the CD4+ T-cell counts and GBV-C viral loads at the acute stage of HIV infection. At the chronic stage (12 months later), this correlation was no longer significant, although it was still positive. Overall, this study demonstrated that pre-existing GBV-C viraemia could not prevent the acquisition of HIV-1 infection and transmission of HIV-1 significantly increased the prevalence of GBV-C viraemia.
Sequence variability in three mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 3 (cox3), NADH dehydrogenase subunits 1 and 4 (nad1 and nad4) in Spirometra erinaceieuropaei spargana from different geographical regions in China was examined. A portion of each of the cox3 (pcox3), nad1 (pnad1) and nad4 genes (pnad4) were amplified separately from individual S. erinaceieuropaei spargana by polymerase chain reaction (PCR). Representative amplicons were subjected to sequencing in order to estimate sequence variability. The sequences of pcox3, pnad1 and pnad4 were 541, 607 and 847 bp in length, respectively. The A+T contents of the sequences were 68.39–68.76% (pcox3), 63.76–64.91% (pnad1) and 67.18–67.77% (pnad4), respectively, while the intra-specific sequence variations within each of the S. erinaceieuropaei spargana were 0–1.5% for pcox3, 0–2.8% for pnad1 and 0–2.7% for pnad4. Phylogenetic analysis using neighbour joining (NJ), maximum likelihood (ML) and maximum parsimony (MP) methods, indicated that all the spargana isolates in Hunan Province represented S. erinaceieuropaei. These findings demonstrated clearly the usefulness of the three mtDNA sequences for population genetics studies of S. erinaceieuropaei spargana of human and animal health significance.
Plasma immersion ion implantation (PIII) is a technique of material processing and surface modification, using controllable negative high voltage pulsed bias to attract the ion generated from the plasma. The method using PIII treatment quickly improves the performance of solar cell made of crystalline silicon, including monocrystalline, multicrystalline and polycrystalline silicon. Hydrogen ions are attracted and quickly implanted into solar cell under a predetermined negative pulse voltage, thus, the passivation of the crystal defects of the solar cell can be realized in a short period. Meanwhile, the properties of the antireflection layer can not be damaged as the proper operating conditions are used. Consequently, the series resistance can be significantly reduced and the filling factor increases as a result. Both the short-circuit and the open-circuit voltage can be increased. The efficiency can be enhanced.
Transmission electron microscope studies of Ti-doped, congruent lithium niobate (LiNbO3) have shown that extended structural faults are only present within the Ti diffused layer (i.e. the wave guiding region). Structural faults have not been observed in undoped control crystals of congruent and stoichiometric LiNbO3. Therefore, it appears that the introduction of Ti is responsible for the formation of these defects. The chemical driving forces which may be controlling the formation of structural faults are discussed.
Diffraction contrast experiments, which have been interpreted in terms of two-beam dynamical theory for a centrosymmetric crystal, indicate that the faults are tensile in nature (i.e. formed by removing a plane of atoms – so-called intrinsic faults) and have a displacement vector of the type c/12/001] when indexed in the hexagonal coordinate system. That is, the displacement vector is along the c-axis. The detailed crystallographic character of the fault planes is not clear; both (118) and (1 1 12) planes have been confirmed from trace analyses and therefore the fault has a shear component. Additional contrast experiments will be required in order to clarify this feature of structural faults in Ti-doped LiNbO3.
Since the extent of these structural faults is tens of microns, they are clearly potential scattering sites for photons. In this regard, a systematic understanding of their origin and thermal stability is crucial to integrated optical device technologies based on LiNbO3 and on the Ti-doped waveguide fabrication technique.
Measurements of the resistive superconducting transition and magnetoresistance of indium metal in the restricted geometry of 50 Å size porous Vycor glass are reported. We have mapped out the upper critical magnetic field versus temperature phase diagram for these transitions for fields up to 20 T and temperatures down to 100 mK. The results are consistent with magnetization measurements by previous authors and can be generally interpreted in terms of the description of inhomogeneous type-II superconductors. The field-induced resistive transitions exhibit unusual behavior not probed by previous bulk-type measurements which may be related to the microstructure of the composite.
A simple effective spherical cluster model of generalized susceptibility enhancements in disordered monodisperse suspensions of conducting spheres is compared with experimental measurements of reduced permittivity and conductance. Good agreement with experiment is obtained by treating the suspension in the Clausius-Mossotti approximation as a mixture of isolated spheres and compact spherical metallized clusters.
The microstrip resonator technique has been applied to study the temperature dependence of the magnetic penetration depth in high quality YBa2Cu3O7−δ thin films. The temperature dependence at low temperatures comes out directly from measured data, with no assumptions about transmission line geometry, dielectric properties, or a model for the temperature dependence of the penetration depth. One can interpret the data in terms of either an exponential decay of λ(T) at low temperatures or as a power law decay. The energy gaps obtained from the exponential decay at low temperature are found to be significantly smaller than weak coupled BCS theory and power-law exponents are in the range of 1.3 to 3.2. These results will be discussed in terms of microscopic theories and the possibility that materials properties dominate the measurement.