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In this paper, the generation of relativistic electron mirrors (REM) and the reflection of an ultra-short laser off the mirrors are discussed, applying two-dimension particle-in-cell 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 rapid expansion. 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 to the resonance between laser and REM. The reflected radiation near this interval and corresponding spectra will be amplified due to the resonance. Through adjusting the arriving time of the probe laser, a certain part of the reflected field could be selectively amplified or depressed, leading to the selective adjustment of the corresponding spectra.
Adolescents have been largely neglected from tuberculosis control efforts. In low- to medium burden settings much of the tuberculosis burden in this age group occurs from school outbreaks. We report on a large tuberculosis outbreak in adolescents from a boarding high school in Jiangsu Province, China. From March to June 2018, a tuberculosis outbreak occurred in a boarding high school. We conducted an outbreak investigation involving clinical diagnostic tests and molecular analysis to determine the outbreak origin. Cases were detected through symptom screening, tuberculin skin testing (TST), chest radiography, sputum smear, solid sputum culture and GeneXpert MTB/RIF. Mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) genotyping and spoligotyping methods were performed on Mycobacterium tuberculosis (M. tuberculosis) isolates to identify the outbreak origin. A total of 845 students and 131 teachers/staff attended a TST screening for tuberculosis infection. The prevalence of elevated tuberculin reactions at ≥5, ≥10 and ≥15 mm was 12.19% (119/976), 6.35% (62/976) and 3.28% (32/976), respectively. Radiographic abnormalities were present in 5.73% (56 of 976) individuals, 40 students and 16 teachers/staff. Of these, 12 students were diagnosed with confirmed tuberculosis. In total, 14 students (two index cases and 12 confirmed cases) were diagnosed and reported in the tuberculosis outbreak, an attack rate of 1.7% (14/847) among students (two index cases and 845 screened students). Results from MIRU-VNTR typing and spoligotyping analyses demonstrated that three M. tuberculosis strains belong to the Beijing family with corresponding MIRU-VNTR alleles. This school-based tuberculosis outbreak among adolescents demonstrates that transmission among individuals in this age group is common and must be prioritised. It suggests that identifying and timely diagnosis of smear-positive cases, especially in the early phase of outbreaks, is the key to preventing further spread among close contacts.
A viscous damping model is proposed based on a simplified equation of fluid motion in a moonpool or the narrow gap formed by two fixed boxes. The model takes into account the damping induced by both flow separation and wall friction through two damping coefficients, namely, the local and friction loss coefficients. The local loss coefficient is determined through specifically designed physical model tests in this work, and the friction loss coefficient is estimated through an empirical formula found in the literature. The viscous damping model is implemented in the dynamic free-surface boundary condition in the gap of a modified potential flow model. The modified potential flow model is then applied to simulate the wave-induced fluid responses in a narrow gap formed by two fixed boxes and in a moonpool for which experimental data are available. The modified potential flow model with the proposed viscous damping model works well in capturing both the resonant amplitude and frequency under a wide range of damping conditions.
Litter size has a great impact on the profit of swine producers. Uterine development is an important determinant of reproduction efficiency and could hence affect litter size. Chinese Erhualian pig is one of the most prolific breeds in the world, even though large phenotypic variation in litter size was observed within Erhualian sows. To dissect the genetic basis of the phenotypic variation, we herein conducted genome-wide association studies for total number born and number born alive (NBA) of Erhualian sows. In total, one significant single nucleotide polymorphism (SNP) (P<1.78e−06) and 11 suggestive SNPs (P<3.57e−05) were identified on 10 chromosomes, confirming seven previously reported quantitative trait loci (QTL) and uncovering six QTL for litter size or uterus length. One locus on Sus scrofa chromosome (SSC) 13 (79.28 to 90.43 Mb) harbored a cluster of suggestive SNPs associated with multiparous NBA. The SNP (rs81447100) within this region was confirmed to be significantly (P<0.05) associated with litter size in Erhualian (n=313), Sutai (n=173) and Yorkshire (n=488) populations. Retinol binding protein 2 and retinol binding protein 1 functionally related to the development of uterus were located in a region of 2 Mb around rs81447100. Moreover, four genes related to embryo implantation and development were also detected around other significant SNPs. Taken together, our findings provide a potential marker (rs81447100) for the genetic improvement of litter size not only in Chinese Erhualian pigs but also in European commercial pig breeds like Yorkshire, and would facilitate the final identification of causative variant(s) underlying the effect of SSC13 QTL on litter size.
Dengue fever (DF) is the most prevalent and rapidly spreading mosquito-borne disease globally. Control of DF is limited by barriers to vector control and integrated management approaches. This study aimed to explore the potential risk factors for autochthonous DF transmission and to estimate the threshold effects of high-order interactions among risk factors. A time-series regression tree model was applied to estimate the hierarchical relationship between reported autochthonous DF cases and the potential risk factors including the timeliness of DF surveillance systems (median time interval between symptom onset date and diagnosis date, MTIOD), mosquito density, imported cases and meteorological factors in Zhongshan, China from 2001 to 2013. We found that MTIOD was the most influential factor in autochthonous DF transmission. Monthly autochthonous DF incidence rate increased by 36·02-fold [relative risk (RR) 36·02, 95% confidence interval (CI) 25·26–46·78, compared to the average DF incidence rate during the study period] when the 2-month lagged moving average of MTIOD was >4·15 days and the 3-month lagged moving average of the mean Breteau Index (BI) was ⩾16·57. If the 2-month lagged moving average MTIOD was between 1·11 and 4·15 days and the monthly maximum diurnal temperature range at a lag of 1 month was <9·6 °C, the monthly mean autochthonous DF incidence rate increased by 14·67-fold (RR 14·67, 95% CI 8·84–20·51, compared to the average DF incidence rate during the study period). This study demonstrates that the timeliness of DF surveillance systems, mosquito density and diurnal temperature range play critical roles in the autochthonous DF transmission in Zhongshan. Better assessment and prediction of the risk of DF transmission is beneficial for establishing scientific strategies for DF early warning surveillance and control.
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was caused by a novel bunyavirus, SFTSV. The study aimed to disclose the epidemiological and clinical characteristics of SFTSV infection in China so far. An integrated clinical database comprising 1920 SFTS patients was constructed by combining first-hand clinical information collected from SFTS sentinel hospitals (n = 1159) and extracted data (n = 761) from published literature. The considered variables comprised clinical manifestations, routine laboratory tests of acute infection, hospitalization duration and disease outcome. SFTSV-IgG data from 19 119 healthy subjects were extracted from the published papers. The key clinical variables, case-fatality rate (CFR) and seroprevalence were estimated by meta-analysis. The most commonly seen clinical manifestations of SFTSV infection were fever, anorexia, myalgia, chill and lymphadenopathy. The major laboratory findings were elevated lactate dehydrogenase, aminotransferase, followed by thrombocytopenia, lymphocytopenia, elevated alanine transaminase and creatine kinase. A CFR of 12·2% was estimated, significantly higher than that obtained from national reporting data, but showing no geographical difference. In our paper, the mortality rate was about 1·9 parts per million. Older age and longer delay to hospitalization were significantly associated with fatal outcome. A pooled seroprevalence of 3·0% was obtained, which increased with age, while comparable for gender. This study represents a clinical characterization on the largest group of SFTS patients up to now. A higher than expected CFR was obtained. A wider spectrum of clinical index was suggested to be used to identify SFTSV infection, while the useful predictor for fatal outcome was found to be restricted.
Arginine kinase (AK) is an important regulation factor of energy metabolism in invertebrate. An arginine kinase gene, named HaAK, was identified to be differentially expressed between Cry1Ac-susceptible (96S) and Cry1Ac-resistant (Bt-R) Helicoverpa armigera larvae using cDNA-amplification fragment length polymorphism analysis. The full-length open reading frame sequence of HaAK gene with 1068 bp was isolated from H. armigera. Quantitative reverse transcription polymerase chain reaction assay revealed that HaAK gene is specifically expressed in multiple tissues and at larval developmental stages. The peak expression level of HaAK was detected in the midgut of the fifth-instar larvae. Moreover, the expression of HaAK was obviously down-regulated in Bt-R larvae. We further constructed a dsRNA vector directly targeting HaAK and employed RNAi technology to control the larvae. The feeding bioassays showed that minute quantities of dsRNA could greatly increase the larval mortality and delay the larval pupation. Silencing of HaAK significantly retarded the larval development, indicating that HaAK is a potential target for RNA interference-based pest management.
To compare the behaviour of sows and the physiological indices of their offspring in stall and group-housing systems, 28 sows were randomly distributed into two systems with 16 sows in stalls, and the other 12 sows were divided into three groups with four sows per pen. The area per sow in stalls and groups was 1.2 and 2.5 m2, respectively. Back fat depth of the sow was measured. Salivary cortisol concentration of the sows, colostrum composition and piglets’ serum biochemical indicators were evaluated. The behaviour of the sows, including agonistic behaviour, non-agonistic social behaviour, stereotypical behaviour and other behaviours at weeks 2, 9 and 14 of pregnancy were analysed. The results showed no differences in the back fat depth of sows. Colostrum protein, triglyceride, triiodothyronine, thyroxine and prolactin concentrations in the whey also demonstrated no significant differences between the two housing systems. Salivary cortisol concentration was significantly higher in the sows housed in groups than the sows in stalls. The concentrations of serum total cholesterol and low-density lipoprotein (LDL) cholesterol were significantly higher in the offspring of sows housed in groups (P=0.006 and 0.005, respectively). The GLM procedure for repeated measures analysis showed the frequency of drinking, and non-agonistic social behaviour was significantly higher in the sows housed in groups than the sows in stalls; yet the frequency of agonistic and sham chewing demonstrated the opposite direction. The duration of standing was significantly longer in the sows housed in groups, but the sitting and stereotypical behaviour duration were significantly shorter compared with the sows in stalls. These results indicated that group housing has no obvious influence on the colostrum composition of sows; however, it was better for sows to express their non-agonistic social behaviour and reduce the frequency of agonistic behaviour and stereotypical behaviour. Meanwhile, group housing during gestation significantly increased serum total cholesterol and LDL cholesterol of offspring.
Convergent studies have highlighted the dysfunction of the amygdala, prefrontal cortex and hippocampus in post-traumatic stress disorder (PTSD). However, only a few studies have investigated the functional connectivity between brain regions in PTSD patients during the resting state, which may improve our understanding of the neuropathophysiology of PTSD. The aim of this study was to investigate patterns of whole-brain functional connectivity in treatment-naive PTSD patients without co-morbid conditions who experienced the 8.0-magnitude earthquake in the Sichuan province of China.
A total of 72 PTSD patients and 86 trauma-exposed non-PTSD controls participated in the resting-state functional magnetic resonance imaging study. All these subjects were recruited from the disaster zone of the 2008 Sichuan earthquake. Functional connectivities between 90 paired brain regions in PTSD patients were compared with those in trauma-exposed non-PTSD controls. Furthermore, Pearson correlation analysis was performed between significantly abnormal connectivities in PTSD patients and their clinician-administered PTSD scale (CAPS) scores.
Compared with non-PTSD controls, PTSD patients showed weaker positive connectivities between the middle prefrontal cortex (mPFC) and the amygdala, hippocampus, parahippocampal gyrus and rectus, as well as between the inferior orbitofrontal cortex and the hippocampus. In addition, PTSD patients showed stronger negative connectivity between the posterior cingulate cortex (PCC) and the insula. The CAPS scores in PTSD patients correlated negatively with the connectivity between the amygdala and the mPFC.
PTSD patients showed abnormalities in whole-brain functional connectivity, primarily affecting the connectivities between the mPFC and limbic system, and connectivity between the PCC and insula.
Previous studies support Beck's cognitive model of vulnerability to depression. However, the relationship between his cognitive triad and other clinical features and risk factors among those with major depression (MD) has rarely been systematically studied.
The three key cognitive symptoms of worthlessness, hopelessness and helplessness were assessed during their lifetime worst episode in 1970 Han Chinese women with recurrent MD. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression.
Compared to patients who did not endorse the cognitive trio, those who did had a greater number of DSM-IV A criteria, more individual depressive symptoms, an earlier age at onset, a greater number of episodes, and were more likely to meet diagnostic criteria for melancholia, postnatal depression, dysthymia and anxiety disorders. Hopelessness was highly related to all the suicidal symptomatology, with ORs ranging from 5.92 to 6.51. Neuroticism, stressful life events (SLEs) and a protective parental rearing style were associated with these cognitive symptoms.
During the worst episode of MD in Han Chinese women, the endorsement of the cognitive trio was associated with a worse course of depression and an increased risk of suicide. Individuals with high levels of neuroticism, many SLEs and high parental protectiveness were at increased risk for these cognitive depressive symptoms. As in Western populations, symptoms of the cognitive trio appear to play a central role in the psychopathology of MD in Chinese women.
Large electrocaloric (EC) effects in ferroelectric polymers and in ferroelectric ceramics have attracted great attention for new refrigeration development which is more environmental friendly and more efficient and thus could be an alternative to the existing vapor-compression refrigerators which consume large energy and release large amount of green house gas. However in the past, all EC effects investigations have been focused on solid state dielectrics. It is interesting to ask whether a large EC effect can also be realized in dielectric fluids. A dielectric fluid with large EC effect could lead to new design of cooling devices with simpler structures than these based on solid state EC materials, for example, they can be utilized as both the refrigerant and heat exchange fluid. Here we present that a large EC effect can be realized in the liquid crystal (LC) 5CB near it's nematic-isotropic (N-I) phase transition. The LC 5CB possesses a large dielectric anisotropy which can induce large polarization change from the isotropic phase to the nematic phase near the N-I transition. An isothermal entropy change of more than 23 Jkg-1K-1 was observed near 39 oC that is just above the N-I transition.
Thermoelectric materials with stable mechanical and chemical properties at high temperature are required for power generation applications. For example, gas temperatures up to 1000°C are normally present in the waste stream of industrial processes and this can be used for electricity generation. There are few semiconductor materials that can operate effectively at these high temperatures. One solution may be the use of wide bandgap materials, and in particular GaN-based materials, which may offer a traditional semiconductor solution for high temperatures thermoelectric power generation. In particular, the ability to both grow GaN-based materials and fabricate them into devices is well understood if their thermoelectric properties are favorable. To investigate the possibility of using III-Nitride and its alloys for thermoelectric applications, we synthesized and characterized room temperature thermoelectric properties of metal organic chemical vapor deposition grown GaN and InGaN with different carrier concentrations and indium compositions. The promising value of Seebeck coefficients and power factors of Si-doped GaN and InGaN indicated that these materials are suitable for thermoelectric applications.
The allelochemicals 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) and 6-methoxy-benzoxazolin-2-one (MBOA) in wheat are considered to have a role in plant defense against weeds. This study explored the effect of proximity to two weeds, wild oat and flixweed, on DIMBOA/MBOA production in wheat seedlings under hydroponic culture to identify whether the breeding of modern wheat varieties with higher concentrations of these compounds could ensure plant-mediated weed control. MBOA was detected and was noted to exert a significant response; its exudation by some wheat seedlings was significantly increased irrespective of whether the roots were in contact with or separate from those of the weeds. The weeds were a source of biotic stress to wheat when grown in proximity to it, and the stress resulted in production of higher levels of MBOA in wheat seedlings, although the concentration varied with the wheat cultivar. Therefore, the synthesis and exudation of DIMBOA/MBOA in wheat seedlings appears to be an active metabolic process influenced by the environment, particularly the presence of weeds.
Dielectric polymers with high energy density with low loss at high electric fields are highly desired for many energy storage and regulation applications. A polar-fluoropolymer blend consisting of a high energy density polar-fluoropolymer of poly(vinylidene fluoride-chlorotrifluoroethylene) (P(VDF-CTFE)) with a low dielectric loss polymer of poly(ethylene-chlorotrifluoroethylene) (ECTFE) was developed and investigated. We show that the two polymers are partially miscible which leads to blends with high energy density and low loss. Moreover, by introducing crosslinking to further tailor the nano-structures of the blends a markedly reduction of losses in the blend films at high field can be achieved. The crosslinked blend films show a dielectric constant of 7 with a dielectric loss of 1% at low field. Furthermore, the blends maintain a high energy density and low loss (∼3%) at high electric fields (> 250 MV/m).
In this work, Dopant Segregated Schottky Barrier (DSSB) and Schottky Barrier (SB) vertical silicon nanowire (VSiNW) diodes were fabricated on p-type Si substrate using CMOS-compatible processes to investigate the effects of segregated dopants at the silicide/silicon interface and different annealing processes on nickel silicide formation in DSSB VSiNW diodes. With segregated dopants at the silicide/silicon interface, VSiNW diodes showed higher on-current, due to an enhanced carrier tunneling, and much lower leakage current. This can be attributed to the altered energy bands caused by the accumulated Arsenic dopants at the interface. Moreover, DSSB VSiNW diodes also gave ideality factor much closer to unity and exhibited lower electron SBH (ΦBn) than SB VSiNW diodes. This proved that interfacial accumulated dopants could impede the inhomogeneous nature of the Schottky diodes and simultaneously, minimize the effect of Fermi level pinning and ionization of surface defect states. Comparing the impact of different silicide formation annealing using DSSB VSiNW diodes, the 2-step anneal process reduces the silicide intrusion length within the SiNW by ~ 5X and the silicide interface was smooth along the (100) direction. Furthermore, the 2-step DSSB VSiNW diode also exhibited much lower leakage current and an ideality factor much closer to unity, as compared to 1-step DSSB VSiNW diode.
We retrospectively analysed the epidemiological data of all hand, foot, and mouth disease (HFMD) cases from the largest paediatric infectious diseases centre in Shanghai between 2007 and 2010. A total of 28 058 outpatients were diagnosed with HFMD, of which 3948 (14·07%) were hospitalized, 730 (2·60%) had complications with neurological disorders and pulmonary oedema/haemorrhage, and 11 (0·04%) died. The peak season was the summer months. Boys were more affected than girls. Since 2008, the major population group affected has shifted from native Shanghainese children attending preschool to migrant children and younger children cared for at home. Children aged 1–4 years constituted 82·27% of cases. EV-A71 was tested in clinical samples taken from severe cases in 2009 and 2010, and from most inpatients in 2010. EV-A71 was positive in 99·17% and 86·31% of severe cases, respectively in 2009 and 2010. All 12 cases with pulmonary oedema or haemorrhage were infected with EV-A71. Ten (90·90%) of 11 fatal cases were attributable to EV-A71 infection. In 2010, EV-A71-positive cases accounted for 54·12% of inpatients. The dominant circulation of EV-A71 led to the outbreak of HFMD and occurrence of severe and fatal cases.
The 2009 novel H1N1 influenza pandemic had a significant impact on Shenzhen's population with 2063 laboratory-confirmed human H1N1 cases and five deaths being reported. We used parameters from two population-based surveys and the Shenzhen Influenza Surveillance System to estimate the total number of H1N1 influenza infections in Shenzhen in the 2009 pandemic. The attack rate of influenza-like illness (ILI) in family households was 11·2% (95% CI 9·4–13·0), with 80·2% (95% CI 77·8–82·5) seeking medical care. The ILI attack rate in workers was 38·1% (95% CI 34·3–41·7) with 72·5% (95% CI 66·9–78·0) seeking medical care. The average H1N1 positive rate in individuals reporting ILI and testing by polymerase chain reaction was 22·7%. A total of 611 000–768 000 people, or 4·7–5·9% of the Shenzhen population, are estimated to have experienced H1N1 influenza. The estimated total number of cases of H1N1 is likely to be 330 times greater than the number of laboratory-confirmed cases.