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The present study deals with a theoretical investigation of a close-contact melting (CCM) process involving a vertical cylinder on a horizontal isothermal surface, where the liquid phase is a non-Newtonian viscoplastic fluid that behaves according to the Bingham model. Accordingly, a new approach is formulated based on the thin layer approximation and different quasi-steady process assumptions. By analytical derivation, an algebraic equation that relates the molten layer thickness and the solid bulk height is developed. The problem is then solved numerically, coupled with another equation for the melting rate. The new model shows that as the yield stress increases the melting rate decreases and the molten layer thickness increases. It is found that under certain conditions, the model can be reduced to a form that allows an analytical solution. The approximate model predicts an exponential dependence of both the melt fraction and the molten layer thickness. Comparison between the numerical and analytical solutions shows that the analytical approximation provides an excellent estimation for sufficiently large values of the yield stress. Dimensional analysis, which is supported by the analytical model results, reveals the dimensionless groups that govern the problem. For the general case, the melt fraction is a function of two dimensionless groups. For the analytical approximation, it is shown that the melt fraction is governed by a single dimensionless group and that the molten layer thickness is governed by two dimensionless groups.
Recent experiments on thin films flowing down a vertical fibre with varying nozzle diameters present a wealth of new dynamics that illustrate the need for more advanced theory. We present a detailed analysis using a full lubrication model that includes slip boundary conditions, nonlinear curvature terms and a film stabilization term. This study brings to focus the presence of a stable liquid layer playing an important role in the full dynamics. We propose a combination of these physical effects to explain the observed velocity and stability of travelling droplets in the experiments and their transition to isolated droplets. This is also supported by stability analysis of the travelling wave solution of the model.
Previous studies have demonstrated that type 1 diabetes mellitus (T1DM) could be triggered by an early childhood infection. Whether maternal infection during pregnancy is associated with T1DM in offspring is unknown. Therefore, we aimed to study the association using a systematic review and meta-analysis. Eighteen studies including 4304 cases and 25 846 participants were enrolled in this meta-analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were synthesised using random-effects models. Subgroup analyses and sensitivity analyses were conducted to assess the robustness of associations. Overall, the pooled analysis yielded a statistically significant association between maternal infection during pregnancy and childhood T1DM (OR 1.31, 95% CI 1.07–1.62). Furthermore, six studies that tested maternal enterovirus infection showed a pooled OR of 1.54 (95% CI 1.05–2.27). Heterogeneity from different studies was evident (I2 = 70.1%, P < 0.001) and was mainly attributable to the different study designs, ascertaining methods and sample size among different studies. This study provides evidence for an association between maternal infection during pregnancy and childhood T1DM.
The parasite Cyathostomum pateratum, which occurs in the large intestine of equines, is a common species of the subfamily Cyathostominae. Cyathostominae nematodes are a complex nematode group for which only limited genetic information has been reported. To re-examine the phylogenetic relationships among Cyathostominae nematodes, we sequenced the complete mitochondrial (mt) genome of Cy. pateratum and compared it with the mt genome of the congeneric species Cyathostomum catinatum. The complete mtDNA sequence of Cy. pateratum was 13,822 bp in length, 16 bp shorter than that of Cy. catinatum. The mtDNA sequences of both species contained 12 protein-coding genes, two rRNA genes and 22 tRNA genes, and all 36 genes were transcribed in the same direction and in the same strand. Pairwise comparisons of the 12 predicted amino acid sequences between Cy. catinatum and Cy. pateratum revealed differences of 0.4–3.1%; the least conserved sequence was that of cytochrome c oxidase subunit 3 (cox3). Phylogenetic analysis of the concatenated amino acid sequences using Bayesian inference and maximum likelihood methods showed that Cy. catinatum and Cy. pateratum clustered together with very high nodal support, and Cylicostephanus goldi was closer to the Cyathostomum nematodes than to other Cyathostominae nematodes. The mtDNA sequence of Cy. pateratum is reported here for the first time. The study will shed some light on the genetic evolution among parasitic nematodes in Cyathostomum.
Some fire ants of the genus Solenopsis have become invasive species in the southern United States displacing native species by competition. Although the displacement pattern seems clear, the mechanisms underlying competitive advantage remain unclear. The ability of ant workers to produce relatively larger amount of alarm pheromone may correspond to relative greater fitness among sympatric fire ant species. Here we report on quantitative intra-specific (i.e. inter-caste) and inter-specific differences of alarm pheromone component, 2-ethyl-3,6-dimethylpyrazine (2E36DMP), for several fire ant species. The alarm pheromone component was extracted by soaking ants in hexane for 48 h and subsequently quantified by gas chromatography-mass spectrometry at single ion monitoring mode. Solenopsis invicta workers had more 2E36DMP than male or female alates by relative weight; individual workers, however, contained significantly less pyrazine. We thus believe that alarm pheromones may serve additional roles in alates. Workers of Solenopsis richteri, S. invicta, and hybrid (S. richteri × S. invicta) had significantly more 2E36DMP than a native fire ant species, Solenopsis geminata. The hybrid fire ant had significantly less 2E36DMP than the two parent species, S. richteri and S. invicta. It seems likely that higher alarm pheromone content may have favored invasion success of exotic fire ants over native species. We discuss the potential role of inter-specific variation in pyrazine content for the relationship between the observed shifts in the spatial distributions of the three exotic fire ant species in southern United States and the displacement of native fire ant species.
The outbreaks of varicella occurring in kindergartens and schools are increasingly notified in Shanghai despite the implementation of one-dose varicella vaccination. We analyzed surveillance data on the notified outbreaks of varicella in Minhang District of Shanghai during 2008–2014. A total of 13 511 varicella cases and 154 outbreaks involving 1558 (11·5%) cases were reported. Annual attack rates of outbreak-associated varicella in outbreak classes were 5·5%–12%. The mean age of the outbreak-associated cases was 8·6 ± 3·1 years. Among 1558 outbreak cases, 660 (42·4%) received one-dose varicella vaccine previously. The proportions of breakthrough varicella infection during outbreaks ranged from 21·5% in 2008 to 86·1% in 2014. Annual breakthrough infection rates in outbreak classes ranged from 5·4% to 7·4%. Breakthrough cases as index cases results in 9·7% of outbreaks, and the average duration of outbreaks was significantly longer in vaccinated cases as index cases than in unvaccinated cases as index cases (11·3 ± 5·8 days vs. 8·6 ± 6·1 days, P < 0·05). The mean time of breakthrough infection since vaccination was 6·2 ± 2·3 years (range 0·6–13·4 years). One-dose varicella vaccination cannot prevent the varicella outbreaks in kindergartens and schools. A second dose of varicella vaccine should be recommended for children.
To examine factors potentially contributing to acutely exacerbated chronic tinnitus initiation using the Tinnitus Handicap Inventory.
Sixty acutely exacerbated chronic tinnitus out-patients were divided into two groups depending on whether hearing loss was aggravated or stable during tinnitus exacerbation. Total Tinnitus Handicap Inventory scores and scores for the three subscales (assessing functional limitations, emotional attitudes and catastrophic thoughts) were analysed.
Total Tinnitus Handicap Inventory scores did not differ between groups. In patients with acutely exacerbated chronic tinnitus and aggravated hearing loss, functional subscale scores were significantly higher after acutely exacerbated chronic tinnitus than at baseline, but catastrophic and emotional subscale scores did not change. In patients with acutely exacerbated chronic tinnitus and stable hearing loss, emotional subscale scores were significantly higher after acutely exacerbated chronic tinnitus than at baseline, but catastrophic and functional subscale scores did not change.
Elevated Tinnitus Handicap Inventory functional subscale scores might indicate further hearing loss, whereas elevated emotional subscale scores might be associated with negative life or work events.
Many studies have used retrospective reports to assess the long-term consequences of early life stress. However, current individual characteristics and experiences may bias the recall of these reports. In particular, depressed mood may increase the likelihood of recall of negative experiences. The aim of the study was to assess whether specific factors are associated with consistency in the reporting of childhood adverse experiences.
The sample comprised 7466 adults from Canada's National Population Health Survey who had reported on seven childhood adverse experiences in 1994/1995 and 2006/2007. Logistic regression was used to explore differences between those who consistently reported adverse experiences and those whose reports were inconsistent.
Among those retrospectively reporting on childhood traumatic experiences in 1994/1995 and 2006/2007, 39% were inconsistent in their reports of these experiences. The development of depression, increasing levels of psychological distress, as well as increasing work and chronic stress were associated with an increasing likelihood of reporting a childhood adverse experience in 2006/2007 that had not been previously reported. Increases in mastery were associated with reduced likelihood of new reporting of a childhood adverse experience in 2006/2007. The development of depression and increases in chronic stress and psychological distress were also associated with reduced likelihood of ‘forgetting’ a previously reported event.
Concurrent mental health factors may influence the reporting of traumatic childhood experiences. Studies that use retrospective reporting to estimate associations between childhood adversity and adult outcomes associated with mental health may be biased.
In the near future, the inactivated enterovirus 71 (EV71) vaccine is expected to become available on the market in China. Since EV71 is a major cause of hand, foot and mouth disease (HFMD), the vaccine is expected to significantly reduce the number of cases, as well as the detrimental economic effect of the disease. However, for a national vaccination strategy to be developed, policy-makers need more information on the socioeconomic burden of EV71 HFMD infection. Based on the 2011 population data, we estimated the clinical and economic effect of EV71 HFMD infection in children aged 0–9 years in Shanghai, China. The annual cost related to HFMD is >US$7.66 million for a population of 1·42 million children aged 0–9 years with an average cost of US$208.2/case. The extrapolated cost for EV71 HFMD infection was US$3.53 million, comprising 46·1% of the overall cost associated with HFMD. Around 97% of all of the HFMD-related expenses were paid for by the families creating a considerable economic burden. Our findings could provide the necessary recommendations on the most effective national EV71 vaccine implementation, as well as a baseline data for assessing the cost-effectiveness of the vaccine in China.
Experimental evidence supporting the theory of hot tail runaway electron (RE) generation has been identified in TEXTOR disruptions. With higher temperature, more REs are generated during the thermal quench. Increasing the RE generation by increasing the temperature, an obvious RE plateau is observed even with low toroidal magnetic field (1.7 T). These results explain the previously found electron density threshold for RE generation.
Boron was incorporated into GaN in order to determine its limits of solubility, its ability of reducing the lattice constant mismatch with 6H-SiC, as well as its effects on the structural and optical properties of GaN epilayers. BxGa1−xN films were deposited on 6H-SiC (0001) substrates at 950 °C by low pressure MOVPE using diborane, trimethylgallium, and ammonia as precursors. A single phase alloy with x=0.015 was successfully produced at a gas reactant B/Ga ratio of 0.005. Phase separation into pure GaN and BxGa1−xN alloy with x=0.30 was deposited for a B/Ga reactant ratio of 0.01. This is the highest B fraction of the wurtzite structure alloy ever reported. For B/Ga ratio ≥ 0.02, no BxGa1−xN was formed, and the solid solution contained two phases: wurtzite GaN and BN based on the results of Auger and x-ray diffraction. The band edge emission of BxGa1−xN varied from 3.451 eV for x=0 with FWHM of 39.2 meV to 3.465 eV for x=0.015 with FWHM of 35.1 meV. The narrower FWHM indicated that the quality of GaN epilayer was improved with small amount of boron incorporation.
Blue and Green long-persistent luminescence materials have been fully developed, and are well featured in production and application. However, long-wavelength emitting materials are very rare relatively. This paper presents some work from our laboratory on the recent progress in long-wavelength emitting long-persistent luminescence materials: Sr3Al2O5Cl2: Eu2+, Tm3+, Sr2SnO4: Sm3+ and Ca2BO3Cl: Eu2+, Dy3+. The initial intensity of Sr3Al2O5Cl2: Eu2+, Tm3+ can reach nearly 5000 mcd/m2 and its afterglow can last about 220 min at recognizable intensity level. Sr2SnO4: Sm3+ has a red emission and its afterglow time of which sintered in vacuum atmosphere increased substantially. With optimum doping concentration and sufficient excitation with UV light, the yellow afterglow of Ca2BO3Cl: Eu2+, Dy3+ can persist over 48 h.
A novel swarm intelligence approach for combinatorial optimization is proposed, which we call probability increment based swarm optimization (PIBSO). The population evolution mechanism of PIBSO is depicted. Each state in search space has a probability to be chosen. The rule of increasing the probabilities of states is established. Incremental factor is proposed to update probability of a state, and its value is determined by the fitness of the state. It lets the states with better fitness have higher probabilities. Usual roulette wheel selection is employed to select states. Population evolution is impelled by roulette wheel selection and state probability updating. The most distinctive feature of PIBSO is because roulette wheel selection and probability updating produce a trade-off between global and local search; when PIBSO is applied to solve the printed circuit board assembly optimization problem (PCBAOP), it performs superiorly over existing genetic algorithm and adaptive particle swarm optimization on length of tour and CPU running time, respectively. The reason for having such advantages is analyzed in detail. The success of PCBAOP application verifies the effectiveness and efficiency of PIBSO and shows that it is a good method for combinatorial optimization in engineering.
This study aimed to investigate the validity and feasibility of cervical oesophagostomy as a treatment for patients with severe dysphagia after radiotherapy for nasopharyngeal carcinoma.
The study retrospectively analysed the clinical data, symptoms, physical signs, treatment and outcomes of 12 patients treated with cervical oesophagostomy for severe dysphagia after radiotherapy for nasopharyngeal carcinoma, from 2006 to 2010.
In all 12 cases, the oesophageal stoma remained stable, without any complications such as pharyngeal fistula or inflammation. No oesophageal stricture or granuloma growth was observed. All patients reported significant improvement in their nutritional status and quality of life after the oesophagostomy surgery.
Cervical oesophagostomy is a valid and feasible method of treating severe dysphagia following radiotherapy for nasopharyngeal carcinoma. Oesophagostomy shows specific advantages over nasogastric tubing, gastrostomy and jejunostomy. Patients' nutrition and quality of life can be improved significantly if cervical oesophagostomy is executed in a timely fashion, especially in cases with severe trismus and multiple radiation-induced cranial nerve palsies unresponsive to rehabilitation.
Most knowledge regarding the effects of antidepressant drugs is at the receptor level, distal from the nervous system effects that mediate their clinical efficacy. Using functional magnetic resonance imaging (fMRI), this study investigated the effects of escitalopram, a selective serotonin reuptake inhibitor (SSRI), on resting-state brain function in patients with major depressive disorder (MDD).
Fourteen first-episode drug-naive MDD patients completed two fMRI scans before and after 8 weeks of escitalopram therapy. Scans were also acquired in 14 matched healthy subjects. Data were analyzed using the regional homogeneity (ReHo) approach.
Compared to controls, MDD patients before treatment demonstrated decreased ReHo in the frontal (right superior frontal gyrus), temporal (left middle and right inferior temporal gyri), parietal (right precuneus) and occipital (left superior occipital gyrus and right cuneus) cortices, and increased ReHo in the left dorsal medial prefrontal gyrus and left anterior lobe of the cerebellum. Compared to the unmedicated state, ReHo in the patients after treatment was decreased in the left dorsal medial prefrontal gyrus, the right insula and the bilateral thalamus, and increased in the right superior frontal gyrus. Compared to controls, patients after treatment displayed a ReHo decrease in the right precuneus and a ReHo increase in the left anterior lobe of the cerebellum.
Successful treatment with escitalopram may be associated with modulation of resting-state brain activity in regions within the fronto-limbic circuit. This study provides new insight into the effects of antidepressants on functional brain systems in MDD.
Helianthus tuberosus L. is regarded as one of the most important bioenergy crops because of its tolerance to arid conditions and its high biomass production. Future breeding programmes will rely on the available germplasm, thus necessitating a critical assessment of genetic diversity and differentiation in the species. The germplasm diversity and regional differentiation of H. tuberosus L. was assessed for 60 accessions collected from East Asia and Europe by means of amplified fragment length polymorphisms (AFLPs), phenotypic traits and chemical analysis. The analysis did not reveal separate clusters for accessions from East Asia and Europe, with 5% for genetic and 0·27% for phenotypic variability, although some regional accessions were closely related to each other with respect to morphological, chemical and genetic variation. Both phenotypic and genetic relationships showed a moderate correlation with colour of tubers, which can be used as an important criterion for germplasm management of the crop. Three major genetic groups were identified from the accessions. Within the groups derived from the genetic data, both morphological and chemical traits were very variable. The most important features of Groups I, II and III were: Group I, strong sexual reproduction, higher above-ground biomass and nutrient content; Group II, longer vegetative growth; Group III, higher tuber yield and total sugar content. High diversity was found in both European and East Asian accessions as well as within each genetic group, suggesting that there is a strong base for future breeding from these plants.
A scheme of generating ultra-intense attosecond pulses in ultra-relativistic laser interaction with under-dense plasmas is proposed. The attosecond pulse emission is caused by an oscillating transverse current sheet formed by an electron density spike composed of trapped electrons in the laser wakefield and the residual transverse momentum of electrons left behind the laser pulse when its front is strongly modulated. As soon as the attosecond pulse emerges, it tends to feed back to further enhance the transverse electron momentum and the transverse current. Consequently, the attosecond pulse is enhanced and developed into a few cycles later until the density spike is depleted out due to the pump laser depletion. To control the formation of the transverse current sheet, a non-uniform plasma slab with an up-ramp density profile in front of a uniform region is adopted, which enables one to obtain attosecond pulses with higher amplitudes than that in a uniform plasma slab.