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In this paper, the generation of relativistic electron mirrors (REMs) and the reflection of an ultra-short laser off this mirrors are discussed, applying two-dimensional particle-in-cell (2D-PIC) simulations. REMs with ultra-high acceleration and expanding velocity can be produced from a solid nanofoil illuminated normally by an ultra-intense femtosecond laser pulse with a sharp rising edge. Chirped attosecond pulse can be produced through the reflection of a counter-propagating probe laser off the accelerating REM. In the electron moving frame, the plasma frequency of the REM keeps decreasing due to its rapidly expanding. The laser frequency, on the contrary, keeps increasing due to the acceleration of REM and the relativistic Doppler shift from the lab frame to the electron moving frame. Within an ultra-short time interval, the two frequencies will be equal in the electron moving frame, which leads the resonance between laser and REM. The reflected radiation near this interval and the corresponding spectra will be amplified due to the resonance. Through adjusting the arriving time of the probe laser, certain part of the reflected field could be selectively amplified or depressed, leading to the selectively adjusting of the corresponding spectra.
Predictors of compliance with aspirin in children following cardiac catheterisation have not been identified. The aim of this study is to identify the caregivers’ knowledge, compliance with aspirin medication, and predictors of compliance with aspirin in children with Congenital Heart Disease (CHD) post-percutaneous transcatheter occlusion.
Methods:
A cross-sectional explorative design was adopted using a self-administered questionnaire and conducted between May 2017 and May 2018. Recruited were 220 caregivers of children with CHD post-percutaneous transcatheter occlusion. Questionnaires included child and caregivers’ characteristics, a self-designed and tested knowledge about aspirin scale (scoring scale 0–2), and the 8-item Morisky Medication Adherence Scale (scoring scale 0–8). Data were analysed using multivariate binary logistic regression analysis to identify predictors of compliance with aspirin.
Results:
Of the 220 eligible children and caregivers, 210 (95.5%) responded and 209 surveys were included in the analysis. The mean score of knowledge was 7.25 (standard deviation 2.27). The mean score of compliance was 5.65 (standard deviation 1.36). Child’s age, length of aspirin use, health insurance policies, relationship to child, monthly income, and knowledge about aspirin of caregivers were independent predictors of compliance with aspirin (p < 0.05).
Conclusion:
Caregivers of children with CHD had an adequate level of knowledge about aspirin. Compliance to aspirin medication reported by caregivers was low. Predictors of medium to high compliance with aspirin were related to the child’s age and socio-economic reasons. Further studies are needed to identify effective strategies to improve knowledge, compliance with medication, and long-term outcomes of children with CHD.
We aimed to describe the clinical features in coronavirus disease 2019 (COVID-19) cases. We studied 134 critically ill COVID-19 cases from 30 December 2019 to 20 February 2020 in an intensive care unit (ICU) at Wuhan Jinyintan Hospital. Demographics, underlying diseases, therapy strategies and test results were collected and analysed from patients on admission, admission to the ICU and 48 h before death. The non-survivors were older (65.46 (s.d. 9.74) vs. 46.45 (s.d. 11.09)) and were more likely to have underlying diseases. The blood group distribution of the COVID-19 cases differed from that of the Han population in Wuhan, with type A being 43.85%; type B, 26.92%; type AB, 10% and type O, 19.23%. Non-survivors tend to develop more severe lymphopaenia, with higher C-reactive protein, interleukin-6, procalcitonin, D-dimer levels and gradually increased with time. The clinical manifestations were non-specific. Compared with survivors, non-survivors more likely to have organ function injury, and to receive mechanical ventilation, either invasively or noninvasively. Multiple organ failure and secondary bacterial infection in the later period is worthy of attention.
The oxidation behavior of the selective laser melting (SLM)–fabricated Inconel 718 was investigated through isothermal oxidation testing at 650 °C for 500 h and compared with that of the as-cast and as-forged specimens at the same testing conditions. The effect of microstructure and surface roughness on the oxidation behavior of the SLM-fabricated, as-cast, and as-forged Inconel 718 specimens was examined. The result shows that Inconel 718 fabricated by SLM with the unique layer structure exhibited a better resistance to the 500 h oxidation at 650 °C compared with as-cast and as-forged 718 with coarse dendritic structure and uniform equiaxed grain microstructure, respectively. The influence of the surface roughness on the long-time oxidation resistance of SLM specimens is not pronounced compared with that of as-cast and as-forged specimens. The tiny dendrites instead of grain boundaries are a major influencing factor for the oxidation process of SLM specimens. The surface roughness has more evident influence on the oxidation resistance of as-forged specimens than that of the as-cast ones subjected to the 500 h oxidation at 650 °C.
The present article reports on a comprehensive atomic-scale investigation on S-series precipitates in 2024 aluminum alloy. Cs-corrected high-angle annular dark-field scanning transmission electron microscopy is applied to reveal the fine atomic-scale structure of precipitates at early ageing state. Geometrics phase analysis is used for elucidating the induced strain field from precipitates. The precipitate sequence of S-series precipitates in 2024 Al alloy is identified as follows: super saturated solid solutions (s.s.s.s.) → clusters (GPB zone) → S′ phase → S phase. The interfaces between precipitates acting as precursor of S′ phase are well characterized. One typical characteristic of S-series phase precipitates is the coexistence of clusters and subsequent metastable phases. Transformation of metastable phases is characterized. Corresponding hardness structure relationship is revealed, and S′ phase is considered as the key strengthening structure in S-series precipitates in 2024 Al alloys.
To reduce the seed length while maintaining the advantages of the cuboid KDP-type crystal, a long-seed KDP crystal with size $471~\text{mm}\times 480~\text{mm}\times 400~\text{mm}$ is rapidly grown. With almost the same high cutting efficiency to obtain third harmonic generation oriented samples, this long-seed KDP-type crystal can be grown with a shorter seed than that of the cuboid KDP-type crystal. The full width at half maximum of the high-resolution X-ray diffraction of the (200) crystalline face is 28.8 arc seconds, indicating that the long-seed KDP crystal has good crystalline quality. In the wavelength range of 377–1022 nm, the transmittance of the long-seed KDP crystal is higher than 90%. The fluence for the 50% probability of laser-induced damage (LID) is $18.5~\text{J}/\text{cm}^{2}$ (3 ns, 355 nm). Several test points survive when the laser fluence exceeds $30~\text{J}/\text{cm}^{2}$ (3 ns, 355 nm), indicating the good LID performance of the long-seed KDP crystal. At present, the growth of a long-seed DKDP crystal is under way.
We report on the generation of a mid-infrared (mid-IR) frequency comb with a maximum average output power of 250 mW and tunability in the 2.7–4.0 μm region. The approach is based on a single-stage difference frequency generation (DFG) starting from a compact Yb-doped fiber laser system. The repetition rate of the near-infrared (NIR) comb is locked at 75 MHz. The phase noise of the repetition rate in the offset-free mid-IR comb system is measured and analyzed. Except for the intrinsic of NIR comb, environmental noise at low frequency and quantum noise at high frequency from the amplifier chain and nonlinear spectral broadening are the main noise sources of broadening the linewidth of comb teeth, which limits the precision of mid-IR dual-comb spectroscopy.
Aging treatment plays an important role in strengthening of 2198 Al–Li alloy. Through a serious of heat treatment processes, a large amount of precipitates emerge, mainly observed to be θ′(Al2Cu), Al3Zr, and T1(Al2CuLi), among which, T1 turns to be the most important precipitate that contributes to the strengthening of 2198 Al–Li alloy. While the temperature of the aging process is 175 °C, the density and size of T1 phase keep increasing through the process and reach peak in about 18 h. T1 phase tends to have a certain orientation relationship of
${\left( {0001} \right)_{{{\rm{T}}_1}}}//{\left\{ {111} \right\}_{{\rm{Al}}}}$
,
${\left\langle {1010} \right\rangle _{{{\rm{T}}_{\rm{1}}}}}//{\left\langle {110} \right\rangle _{{\rm{Al}}}}$
and may have different kinds of multilayered structures. In most of the multilayered structures, the distance between two adjacent copper-rich laths is less than that in classical single-layered phase. Thus, it can be inferred that the microstructure of T1 phase might change in the process of developing from single-layered structure to multilayered structure. In addition, the interactions between different phases become relatively frequent when the density of T1 phase reaches a threshold.
China’s emergency management of severe acute respiratory syndrome (SARS) was heavily criticized, whereas the H7N9 response was praised by the international community.
Aims
The aims of this study were to examine and compare the strengths and weaknesses of risk communication conducted in response to SARS and H7N9 and their associated social impacts on affected communities in China.
Method
A qualitative comparative case study approach was employed in the present study, using a set of 8 risk communication principles selected from international literature to suit the Chinese context for the comparative analysis of emergency responses of SARS and H7N9.
Results
The study found significant differences in the risk communication conducted in the 2 cases. The SARS outbreak fully exposed China’s lack of experience in public health risk communication. By contrast, the Chinese government’s risk communication strategies had improved significantly during the H7N9 outbreak.
Discussion
Trust is the basis for communication. Maintaining an open and honest attitude and actively engaging stakeholders to address their risk information needs will serve to build trust and facilitate multi-sector collaborations in dealing with a public health crisis.
Conclusions
From SARS to H7N9, risk communication practices in China greatly improved, which, in turn, lessened adverse social impacts and improved outcomes in emergency management of public health crises. (Disaster Med Public Health Preparedness. 2018;12:587–598)
Although many studies worldwide have focused on the relationship between vitamin D and insulin resistance, results remain controversial. Furthermore, concentrations of serum 25-hydroxyvitamin D (25(OH)D) in the Chinese population are unclear. We aimed to investigate vitamin D status and its correlation with insulin resistance among a Chinese adult population.
Design
Serum 25(OH)D, fasting blood glucose, fasting insulin, glycated Hb (HbA1c) and other metabolic parameters were assessed. Neck circumference, waist circumference, hip circumference, weight and height were also measured. Lifestyle factors including smoking and drinking status were obtained. Diabetes mellitus was diagnosed by HbA1c according to the 2010 American Diabetes Association criteria.
Setting
Eastern China.
Subjects
Of 7200 residents included, 6597 individuals were ultimately analysed.
Results
We enrolled 2813 males (mean age 52·7 (sd 13·5) years) and 3784 females (52·3 (sd 13·5) years); mean serum 25(OH)D concentration was 43·1 (sd 11·6) and 39·6 (sd 9·8) nmol/l, respectively. Additionally, 83·3 % of participants were 25(OH)D deficient. A significant difference in 25(OH)D was observed between males and females in winter and spring (P<0·001). Furthermore, 25(OH)D concentrations were inversely associated with the homeostasis model assessment of insulin resistance (HOMA-IR) in the overweight and pre-diabetic populations. After adjusting for several variables, 25(OH)D was significantly associated with HOMA-IR in winter. When 25(OH)D values were categorized into quartiles, HOMA-IR was significantly associated with decreasing 25(OH)D.
Conclusions
The majority of the Chinese population was vitamin D deficient and this deficiency was negatively associated with insulin resistance, particularly in the overweight and pre-diabetic populations. Moreover, these associations might be more evident in the winter.
Nitrogen is an essential element for biological activity, and nitrogen isotopic compositions of geological samples record information about both marine biological processes and environmental evolution. However, only a few studies of N isotopes in the early Cambrian have been published. In this study, we analysed nitrogen isotopic compositions, as well as trace elements and sulphur isotopic compositions of cherts, black shales, carbonaceous shales and argillaceous carbonates from the Daotuo drill core in Songtao County, NE Guizhou Province, China, to reconstruct the marine redox environment of both deep and surface seawater in the study area of the Yangtze shelf margin in the early Cambrian. The Mo–U covariation pattern of the studied samples indicates that the Yangtze shelf margin area was weakly restricted and connected to the open ocean through shallow water flows. Mo and U concentrations, δ15Nbulk and δ34Spy values of the studied samples from the Yangtze shelf margin area suggest ferruginous but not sulphidic seawater and low marine sulphate concentration (relatively deep chemocline) in the Cambrian Fortunian and early Stage 2; sulphidic conditions (shallow chemocline and anoxic photic zone) in the upper Cambrian Stage 2 and lower Stage 3; and the depression of sulphidic seawater in the middle and upper Cambrian Stage 3. Furthermore, the decreasing δ15N values indicate shrinking of the marine nitrate reservoir during the middle and upper Stage 3, which reflects a falling oxygenation level in this period. The environmental evolution was probably controlled by the changing biological activity through its feedback on the local marine environment.
In this paper, a bilinear Streamline-Diffusion finite element method on Bakhvalov-Shishkin mesh for singularly perturbed convection – diffusion problem is analyzed. The method is shown to be convergent uniformly in the perturbation parameter ∈ provided only that ∈ ≤ N–1. An convergent rate in a discrete streamline-diffusion norm is established under certain regularity assumptions. Finally, through numerical experiments, we verified the theoretical results.
Intra-uterine growth restriction (IUGR) impairs postnatal growth and skeletal muscle development in neonatal infants. This study evaluated whether dietary β-hydroxy-β-methylbutyrate Ca (HMB-Ca) supplementation during the early postnatal period could improve muscle growth in IUGR neonates using piglets as a model. A total of twelve pairs of IUGR and normal-birth-weight (NBW) male piglets with average initial weights (1·85 (sem 0·36) and 2·51 (sem 0·39) kg, respectively) were randomly allotted to groups that received milk-based diets (CON) or milk-based diets supplemented with 800 mg/kg HMB-Ca (HMB) during days 7–28 after birth. Blood and longissimus dorsi (LD) samples were collected and analysed for plasma amino acid content, fibre morphology and the expression of genes related to muscle development. The results indicate that, regardless of diet, IUGR piglets had a significantly decreased average daily weight gain (ADG) compared with that of NBW piglets (P<0·05). However, IUGR piglets fed HMB-Ca had a net weight and ADG similar to that of NBW piglets fed the CON diet. Irrespective of body weight (BW), HMB-Ca supplementation markedly increased the type II fibre cross-sectional area and the mRNA expression of mammalian target of rapamycin (mTOR), insulin-like growth factor-1 and myosin heavy-chain isoform IIb in the LD of piglets (P<0·05). Moreover, there was a significant interaction between the effects of BW and HMB on mTOR expression in the LD (P<0·05). In conclusion, HMB-Ca supplementation during the early postnatal period could improve skeletal muscle growth and maturity by accelerating fast-twitch glycolytic fibre development in piglets.
SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%. We review the laser system and introduce the SG-III laser performance here.
Identification of individuals within pairs of monozygotic (MZ) twins remains unresolved using common forensic DNA typing technology. For some criminal cases involving MZ twins as suspects, the twins had to be released due to inability to identify which of the pair was the perpetrator. In this study, we performed a genome-wide scan on whole blood-derived DNA from four pairs of healthy phenotypically concordant MZ twins using the methylated DNA immunoprecipitation sequencing technology to identify candidate DNA methylation markers with capacity to distinguish MZ twins within a pair. We identified 38 differential methylation regions showing within-pair methylation differences in all four MZ pairs. These are all located in CpG islands, 17 of which are promoter-associated, 17 are intergenic islands, and four are intragenic islands. Genes associated with these markers are related with cell proliferation, differentiation, and growth and development, including zinc finger proteins, PRRX2, RBBP9, or are involved in G-protein signaling, such as the regulator of G-protein signaling 16. Further validation studies on additional MZ twins are now required to evaluate the broader utility of these 38 markers for forensic use.
By
Zhidong Tu, Icahn School of Medicine at Mount Sinai, New York, NY,
Bin Zhang, Icahn School of Medicine at Mount Sinai, New York, NY,
Jun Zhu, Icahn School of Medicine at Mount Sinai, New York, NY
Understanding the molecular mechanisms underlying the connections between genotype and phenotype in human is one of the most important biological questions.By integrating genomic and genetic information to constructing network models, we demonstrate that potential gene regulatory mechanisms and key genes can be identified. We review multiple network algorithms that have been applied to discovering the key pathways linking the genetic and phenotype. Using two application examples, we show that novel hypotheses can be formed and experimentally validated to help us to better understand human complex diseases.
Introduction
A major goal in current biomedical research is to understand the mechanisms of various diseases to allow the development of novel or improved treatments. For complex diseases (e.g., cancers, diabetes, and cardiovascular diseases), multiple genetic factors interact with environmental factors to determine the disease development and progression (Hunter, 2005; Schadt, 2009). With recent large efforts in genome-wide association studies (GWAS), thousands of genetic variants have been identified for the association with various disease phenotypes. However, for most of these variants, little is known of their mechanisms of causing disease. This poses a major challenge for complex disease research in the post-GWAS era. For variants in the protein coding region that lead to nonsynonymous changes, it is reasonable to suspect that disease phenotypes are the consequence of the aberrant changes from the corresponding proteins’ function. However, more than 80% of these single nucleotide polymorphisms (SNPs) are located in noncoding regions, most of them are likely to function through gene expression regulation (Schaub et al., 2012). This is supported by the findings that GWAS SNPs are enriched within DNase I hypersensitive (DHS) sites (Maurano et al., 2012) and more likely to be eQTL (expression quantitative trait locus) SNPs (Nicolae et al., 2010). With the advancement of high-throughput technologies to allow quantitatively measuring the whole transcriptome, studying the genetics of genome-wide gene expression regulation became possible and was first performed in yeast (Brem et al., 2002) and then quickly applied to other species like mouse and human (Cheung et al., 2003; Schadt et al., 2003).
Background: Multiple sclerosis (MS) is a lifelong neurological disorder requiring care in a variety of settings. The purpose of this study is to describe preferences of general practitioners (GPs) with regards to providing care for MS patients.Methods: A stratified sample of 900 GPs in the province of Quebec were sent a questionnaire, with 266 returning completed questionnaires. Respondents were surveyed about their preferences using four clinical scenarios describing hypothetical patients experiencing different stages of MS. Respondents were asked whether they would continue managing the patient themselves, formally refer the patient to a specialist, or seek specialist advice.Results: In two scenarios representing stable courses, 40.9% and 61.6% of GPs, respectively, intended to manage the patient themselves. GPs who reported having experience with MS patients were more likely to report an intention to continue management. In one scenario, GPs operating in rural areas were less likely to consider management than those in the Montreal metropolitan area (odds ratio=0.422, 95% confidence interval 0.20-0.90). Conclusions: For MS patients with a stable disease course, an important proportion of GPs appear to be willing to manage long-term care for MS patients.
Au nanoparticles (Au NPs) have attracted much interest owing to their unique optical properties. In this paper, a facile process has been successfully developed to synthesize the SiO2/Au hybrid microspheres with a diameter of 200 nm via the galvanic replacement of SiO2/Ag hybrid microspheres and chlorauric acid (HAuCl4) solution. The as-prepared products were investigated by x-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM, JEOL-6700F), and transmission electron microscopy (TEM, JEOL 3010), respectively. As expected, the as-prepared SiO2/Au hybrid microspheres show strong chemical stability and superior catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The SiO2/Au hybrid microspheres would be found widely used in wastewater treatment, catalytic reaction, bacteriostatic and bactericidal applications.