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Discovering knowledge from data is a quantum jump from quantity to quality, which is the characteristic and the spirit of the development of science. Symbolic regression (SR) is playing a greater role in the discovery of knowledge from data, specifically in this era of exponential data growth, because SRs are able to discover mathematical formulas from data. These formulas may provide scientifically meaningful models, especially when combined with domain knowledge. This article provides an overview of SR applications in the field of materials science and engineering. Integrating domain knowledge with SR is the key and a crucial approach, which allows gaining knowledge from data quickly, accurately, and scientifically. In the data-driven paradigm, SR allows for uncovering the underlying mechanisms of materials behavior, properties, and functions, in a wide range of areas from basic academic research to industrial applications, including experiments and computations, by providing explicit interpretable models from data, in comparison with other machine-learning “black-box” models. SR will be a powerful tool for rational and automatic materials development.
While assessing the environmental impact of nuclear power plants, researchers have focused their attention on radiocarbon (14C) owing to its high mobility in the environment and important radiological impact on human beings. The 10 MW high-temperature gas-cooled reactor (HTR-10) is the first pebble-bed gas-cooled test reactor in China that adopted helium as primary coolant and graphite spheres containing tristructural-isotropic (TRISO) coated particles as fuel elements. A series of experiments on the 14C source terms in HTR-10 was conducted: (1) measurement of the specific activity and distribution of typical nuclides in the irradiated graphite spheres from the core, (2) measurement of the activity concentration of 14C in the primary coolant, and (3) measurement of the amount of 14C discharged in the effluent from the stack. All experimental data on 14C available for HTR-10 were summarized and analyzed using theoretical calculations. A sensitivity study on the total porosity, open porosity, and percentage of closed pores that became open after irradiating the matrix graphite was performed to illustrate their effects on the activity concentration of 14C in the primary coolant and activity amount of 14C in various deduction routes.
UK guidelines recommend routine HIV testing in high prevalence emergency departments (ED) and targeted testing for HBV and HCV. The ‘Going Viral’ campaign implemented opt-out blood-borne virus (BBV) testing in adults in a high prevalence ED, to assess seroprevalence, uptake, linkage to care (LTC) rates and staff time taken to achieve LTC. Diagnosis status (new/known/unknown), current engagement in care, and severity of disease was established. LTC was defined as patient informed plus ⩾1 clinic visit. A total of 6211/24 981 ED attendees were tested (uptake 25%); 257 (4.1%) were BBV positive (15 co-infected), 84 (33%) required LTC. 100/147 (68%) HCV positives were viraemic; 44 (30%) required LTC (13 new, 16 disengaged). 26/54 (48%) HBV required LTC (seven new, 11 disengaged). 16/71 (23%) HIV required LTC (10 new, five disengaged). 26/84 (31%) patients requiring LTC had advanced disease (CD4 <350, APRI (AST-to-Platelet Ratio Index) >1, Fibroscan F3/F4 or liver cancer), including five with AIDS-defining conditions and three hepatocellular carcinomas. There were five BBV-related deaths. BBV prevalence was high (4.1%); most were HCV (2.4%). HIV patients were more successfully and quickly LTC than HBV or HCV patients. ED testing was valuable as one-third of those requiring LTC (new, disengaged or unknown status patients) had advanced disease.
High cost of healthy foods could be a barrier to healthy eating. We aimed to examine the association between dietary cost and adherence to the Mediterranean diet in a non-Mediterranean country. We evaluated cross-sectional data from 12 417 adults in the UK Fenland Study. Responses to 130-item FFQ were used to calculate a Mediterranean diet score (MDS). Dietary cost was estimated by matching food consumption data with retail prices of five major supermarkets. Using multivariable-adjusted linear regression, we examined the association of MDS and individual foods with dietary cost in absolute and relative scales. Subsequently, we assessed how much the association was explained by education, income, marital status and occupation, by conducting mediation analysis and testing interaction by these variables. High compared with low MDS (top to bottom third) was associated with marginally higher cost by 5·4 % (95 % CI 4·4, 6·4) or £0·20/d (95 % CI 0·16, 0·25). Participants with high adherence had higher cost associated with the healthier components (e.g. vegetables, fruits and fish), and lower cost associated with the unhealthy components (e.g. red meat, processed meat and sweets) (Pfor trend<0·001 each). In total, 20·7 % (95 % CI 14·3, 27·0) of the MDS-cost association was explained by the selected socio-economic factors, and the MDS-cost association was of greater magnitude in lower socio-economic groups (Pinteraction<0·005). Overall, greater adherence to the Mediterranean diet was associated with marginally higher dietary cost, partly modified and explained by socio-economic status, but the potential economic barriers of high adherence might be offset by cost saving from reducing unhealthy food consumption.
This study aims to investigate the climate–malaria associations in nine cities selected from malaria high-risk areas in China. Daily reports of malaria cases in Anhui, Henan, and Yunnan Provinces for 2005–2012 were obtained from the Chinese Center for Disease Control and Prevention. Generalized estimating equation models were used to quantify the city-specific climate–malaria associations. Multivariate random-effects meta-regression analyses were used to pool the city-specific effects. An inverted-U-shaped curve relationship was observed between temperatures, average relative humidity, and malaria. A 1 °C increase of maximum temperature (Tmax) resulted in 6·7% (95% CI 4·6–8·8%) to 15·8% (95% CI 14·1–17·4%) increase of malaria, with corresponding lags ranging from 7 to 45 days. For minimum temperature (Tmin), the effect estimates peaked at lag 0 to 40 days, ranging from 5·3% (95% CI 4·4–6·2%) to 17·9% (95% CI 15·6–20·1%). Malaria is more sensitive to Tmin in cool climates and Tmax in warm climates. The duration of lag effect in a cool climate zone is longer than that in a warm climate zone. Lagged effects did not vanish after an epidemic season but waned gradually in the following 2–3 warm seasons. A warming climate may potentially increase the risk of malaria resurgence in China.
This study was conducted to evaluate the effect of a 12-h light, 12-h dark (12L : 12D) photoperiod of green light during day 1 to day 18 of incubation time, on embryo growth, hormone concentration and the hatch process. In the test group, monochromatic light was provided by a total of 204 green light-emitting diodes (522 nm) mounted in a frame which was placed above the top tray of eggs to give even spread of illumination. No light–dark cycle was used in the control group. Four batches of eggs (n=300/group per batch) from fertile Ross 308 broiler breeders were used in this experiment. The beak length and crown–rump length of embryos incubated under green light were significantly longer than that of control embryos at day 10 and day 12, respectively (P<0.01). Furthermore, green light-exposed embryos had a longer third toe length compared with control embryos at day 10, day 14 and day 17 (P=0.02). At group level (n=4 batches), light stimulation had no effect on chick weight and quality at take-off, the initiation of hatch and hatch window. However, the individual hatching time of the light exposure focal chicks (n=33) was 3.4 h earlier (P=0.49) than the control focal chicks (n=36) probably due to the change in melatonin rhythm of the light group. The results of this study indicate that green light accelerates embryo development and alters hatch-related hormones (thyroid and corticosterone), which may result in earlier hatching.
The Yellow Sea region is of high global importance for waterbird populations, but recent systematic bird count data enabling identification of the most important sites are relatively sparse for some areas. Surveys of waterbirds at three sites on the coast of southern Jiangsu Province, China, in 2014 and 2015 produced peak counts of international importance for 24 species, including seven globally threatened and six Near Threatened species. The area is of particular global importance for the ‘Critically Endangered’ Spoon-billed Sandpiper Calidris pygmaea (peak count across all three study sites: 62 in spring  and 225 in autumn  and ‘Endangered’ Spotted Greenshank Tringa guttifer (peak count across all three study sites: 210 in spring  and 1,110 in autumn ). The southern Jiangsu coast is therefore currently the most important migratory stopover area in the world, in both spring and autumn, for both species. Several serious and acute threats to waterbirds were recorded at these study sites. Paramount is the threat of large-scale land claim which would completely destroy intertidal mudflats of critical importance to waterbirds. Degradation of intertidal mudflat habitats through the spread of invasive Spartina, and mortality of waterbirds by entrapment in nets or deliberate poisoning are also real and present serious threats here. Collisions with, and displacement by, wind turbines and other structures, and industrial chemical pollution may represent additional potential threats. We recommend the rapid establishment of effective protected areas for waterbirds in the study area, maintaining large areas of open intertidal mudflat, and the urgent removal of all serious threats currently faced by waterbirds here.
A pilot study by 6 Clinical and Translational Science Awards (CTSAs) explored how bibliometrics can be used to assess research influence.
Evaluators from 6 institutions shared data on publications (4202 total) they supported, and conducted a combined analysis with state-of-the-art tools. This paper presents selected results based on the tools from 2 widely used vendors for bibliometrics: Thomson Reuters and Elsevier.
Both vendors located a high percentage of publications within their proprietary databases (>90%) and provided similar but not equivalent bibliometrics for estimating productivity (number of publications) and influence (citation rates, percentage of papers in the top 10% of citations, observed citations relative to expected citations). A recently available bibliometric from the National Institutes of Health Office of Portfolio Analysis, examined after the initial analysis, showed tremendous potential for use in the CTSA context.
Despite challenges in making cross-CTSA comparisons, bibliometrics can enhance our understanding of the value of CTSA-supported clinical and translational research.
We use cyclic charge-discharge experiments to evaluate the capacity retention rates of two quinone-bromide flow batteries (QBFBs). These aqueous QBFBs use a negative electrolyte containing either anthraquinone-2,7-disulfonic acid (AQDS) or anthraquinone-2-sulfonic acid (AQS) dissolved in sulfuric acid, and a positive electrolyte containing bromine and hydrobromic acid. We find that the AQS cell exhibits a significantly lower capacity retention rate than the AQDS cell. The observed AQS capacity fade is corroborated by NMR evidence that suggests the formation of hydroxylated products in the electrolyte in place of AQS. We further cycle the AQDS cell and observe a capacity fade rate extrapolating to 30% loss of active species after 5000 cycles. After about 180 cycles, bromine crossover leads to sufficient electrolyte imbalance to accelerate the capacity fade rate, indicating that the actual realization of long cycle life will require bromine rebalancing or a membrane less permeable than Nafion® to molecular bromine.
One-third of all primary central nervous system tumors in adults are meningiomas, which arise from the meninges. Although the majority of meningioma cases are not associated with an environmental risk factor, it is well established that individuals receiving radiation treatment to the CNS are susceptible to radiation-induced meningiomas (RIMs). The genomic integrity of spontaneous meningiomas has been extensively profiled by whole genome sequencing and exome sequencing, providing a well-developed catalogue of meningioma associated mutations. In contrast, a comprehensive understanding of the molecular changes associated with RIMs is not available. Comparative genomic hybridization (CGH) has previously revealed that >90% of RIMs possess multiple regions of DNA copy number alterations, with the most common chromosomal loss being chromosome 1p and 22q. These CGH based studies of gross chromosomal alterations suggest that radiation induced meningiomas show no significant differences to spontaneous meningiomas. We have extensively characterized RIMs through the profiling of their global CpG methylation, gene expression and mutation signatures. The integration of these three platforms at base-pair resolution methylation has facilitated the identification of molecular changes that contribute to RIM. This is the largest cohort of profiled meningiomas to date, providing a robust characterization of unique RIM features that can be exploited for future therapies.
Factors which might influence outcome in patients with meningioma are not well-understood. Previous studies have examined associations of laboratory blood values including hemoglobin levels with patient outcomes in cancer. We hypothesized those changes in CBC before tumor resection can be used as one of the prognostic factors for tumor recurrence/progression in meningioma. To address this, we gathered the clinical and pre-operative CBC results for final analysis from 226 patients (64 males and 162 females) who underwent craniotomy for primary meningioma (grades: 157 WHO GI, 59 GII, 10 GIII) at our institution between 2001 and 2015.Individual parameters were analyzed for correlation with progression-free survival. The median recurrence free survival (RFS) was not reached and follow-up ranged 0.3-14 years. Fifty-six patients (25%) had anemia and 30% of the patients showed leukocytosis using standard cut-offs. On univariate analyses, low hemoglobin (Hb) level, as well as high leukocytes (Lkc), neutrophil (Neutro) and monocyte counts correlated with worse RFS. As expected, tumor grade was correlated with RFS. Low Hb level, high Lkc and Neutro counts were all significantly associated with RFS after adjusting for grade. Strikingly, 32% of patients with pre-operative anemia experienced a recurrence at 5 years, compared with only 11% of non-anemic patients. Conclusion: In this exploratory study, we find that pre-operative CBC data, which is readily available, may contain prognostic information relevant to subsequent risk of recurrence or progression in meningioma. While the biological mechanism for these associations is not clear, they represent hypotheses for further investigation.
crAssphage is a newly discovered gut bacteriophage. However, its pathogenicity and molecular epidemiology in humans are as yet unclear. In this study, we investigated the association between crAssphage and diarrhoea, as well as the molecular epidemiology of crAssphage in Chinese patients from our hospital. Our results indicated that there were no significant differences in the crAssphage-positive ratio and viral loads in faecal supernatants between adults with diarrhoea and healthy adults. Of infants and children with diarrhoea, 2·8% were found to be crAssphage-positive, including two infants aged <1 month. Markedly, of all confirmed crAssphage-positive strains, 100% had the ORF00039 deletion and 77·8% had low identity of ORF00018 compared to crAssphage (GenBank accession no. NC_024711, designated genotype 1). Thus, crAssphage was not associated with diarrhoea and most strains of crAssphage in Chinese patients (designated genotype 2) were characterized by the ORF00039 deletion and low identity of ORF00018.
Declines in populations of the Critically Endangered Spoon-billed Sandpiper Calidris pygmaeus have been rapid, with the breeding population now perhaps numbering fewer than 120 pairs. The reasons for this decline remain unresolved. Whilst there is evidence that hunting in wintering areas is an important factor, loss of suitable habitat on passage and wintering areas is also of concern. While some key sites for the species are already documented, many of their wintering locations are described here for the first time. Their wintering range primarily stretches from Bangladesh to China. Comprehensive surveys of potential Spoon-billed Sandpiper wintering sites from 2005 to 2013 showed a wide distribution with three key concentrations in Myanmar and Bangladesh, but also regular sites in China, Vietnam and Thailand. The identification of all important non-breeding sites remains of high priority for the conservation of the species. Here, we present the results of field surveys of wintering Spoon-billed Sandpipers that took place in six countries between 2005 and 2013 and present species distribution models which map the potential wintering areas. These include known and currently unrecognised wintering locations. Our maximum entropy model did not identify any new extensive candidate areas within the winter distribution, suggesting that most key sites are already known, but it did identify small sites on the coast of eastern Bangladesh, western Myanmar, and the Guangxi and Guangdong regions of China that may merit further investigation. As no extensive areas of new potential habitat were identified, we suggest that the priorities for the conservation of this species are habitat protection in important wintering and passage areas and reducing hunting pressure on birds at these sites.
We determined the prevalence and seasonality of infections by Fasciola of goats and bovine species (cattle and water buffalo) in Hubei and Anhui provinces of China. Faecal samples were collected at 2- to 3-month intervals from 200 goats in Hubei province and from 152 bovine species in Anhui province. All faecal samples were examined for the presence of parasites. We determined the nucleotide sequences of the first and second internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA (rDNA) of 39 Fasciola worms from Anhui province. The prevalence of Fasciola infection in goats ranged between 3.5 and 37.0%, with mean eggs per gram (EPG) ranging between 29.0 and 166.0. Prevalence and EPG exhibited downward trends over time with significant differences. The prevalence of Fasciola infection in cattle ranged between 13.3 and 46.2% (mean EPG, 36.4–100.0), and that of water buffalo ranged between 10.3 and 35.4% (mean EPG, 25.0–89.6), with a higher prevalence of infection and EPG from June to October compared with December to March. Analysis of ITS-1 and ITS-2 sequences revealed that F. hepatica and F. gigantica were present in all bovine species of Anhui province and that F. gigantica mainly infected water buffalo. This is the first demonstration of Fasciola infection in Hubei province and detection of F. hepatica and F. gigantica in Anhui province. The present study of Hubei province shows that mass treatment of livestock with closantel sodium injections in April and August/September controlled Fasciola infection effectively.
An unlinked anonymous study was conducted to estimate the prevalence of hepatitis C virus (HCV) infection in emergency department (ED) attendees at a London Hospital. Nine hundred and ninety-seven samples collected over a 12-day period were tested for HCV antibody (Ab) and reactive samples were further tested for HCV RNA. The HCV seroprevalence was 2·6% (26/997) with 1·2% (12/997) HCV RNA positive. A peak HCV RNA-positive prevalence of 4·8% (3/63) was found in males aged 35–44 years, this was compared to 0% (0/136) in males aged <35 years (P = 0·0614) and 1·4% (4/278) in males aged ⩾45 years (P = 0·2415). Assuming the cost for HCV Ab is £6 and HCV RNA is £40 per test, screening ED attendees aged 25–54 years would cost £360 per viraemic infection and identify 82% of those who were HCV RNA positive, yielding the most favourable cost/benefit ratio. HCV screening of ED attendees aged 25–54 years in this population could be an effective way of identifying patients and limit onward transmission.
We conducted a systematic review to compare resistance to third-generation cephalosporins (TGCs) in Shigella strains between Europe-America and Asia-Africa from 1998 to 2012 based on a literature search of computerized databases. In Asia-Africa, the prevalence of resistance of total and different subtypes to ceftriaxone, cefotaxime and ceftazidime increased markedly, with a total prevalence of resistance up to 14·2% [95% confidence interval (CI) 3·9–29·4], 22·6% (95% CI 4·8–48·6) and 6·2% (95% CI 3·8–9·1) during 2010–2012, respectively. By contrast, resistance rates to these TGCs in Europe-America remained relatively low – less than 1·0% during the 15 years. A noticeable finding was that certain countries both in Europe-America and Asia-Africa, had a rapid rising trend in the prevalence of resistance of S. sonnei, which even outnumbered S. flexneri in some periods. Moreover, comparison between countries showed that currently the most serious problem concerning resistance to these TGCs appeared in Vietnam, especially for ceftriaxone, China, especially for cefotaxime and Iran, especially for ceftazidime. These data suggest that monitoring of the drug resistance of Shigella strains should be strengthened and that rational use of antibiotics is required.
We report on a direct measurement of electrical potential and field profiles across the n-i-p junction of hydrogenated nanocrystalline silicon (nc-Si:H) solar cells, using the nanometer-resolution potential imaging technique of scanning Kelvin probe force microscopy (SKPFM). It was observed that the electric field is nonuniform across the i layer. It is much higher in the p/i region than in the middle and the n/i region, illustrating that the i layer is actually slightly n-type. A measurement on a nc-Si:H cell with a higher oxygen impurity concentration shows that the nonuniformity of the electric field is much more pronounced than in samples having a lower O impurity, indicating that O is an electron donor in nc-Si:H materials. This nonuniform distribution of electric field implies a mixture of diffusion and drift of carrier transport in the nc-Si:H solar cells. The composition and structure of these nc-Si:H cells were further investigated by using secondary-ion mass spectrometry and Raman spectroscopy, respectively. The effects of impurity and structural properties on the electrical potential distribution and solar cell performance are discussed.