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The COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) project is a large international collaborative effort to analyze individual-level phenotype data from twins in multiple cohorts from different environments. The main objective is to study factors that modify genetic and environmental variation of height, body mass index (BMI, kg/m2) and size at birth, and additionally to address other research questions such as long-term consequences of birth size. The project started in 2013 and is open to all twin projects in the world having height and weight measures on twins with information on zygosity. Thus far, 54 twin projects from 24 countries have provided individual-level data. The CODATwins database includes 489,981 twin individuals (228,635 complete twin pairs). Since many twin cohorts have collected longitudinal data, there is a total of 1,049,785 height and weight observations. For many cohorts, we also have information on birth weight and length, own smoking behavior and own or parental education. We found that the heritability estimates of height and BMI systematically changed from infancy to old age. Remarkably, only minor differences in the heritability estimates were found across cultural–geographic regions, measurement time and birth cohort for height and BMI. In addition to genetic epidemiological studies, we looked at associations of height and BMI with education, birth weight and smoking status. Within-family analyses examined differences within same-sex and opposite-sex dizygotic twins in birth size and later development. The CODATwins project demonstrates the feasibility and value of international collaboration to address gene-by-exposure interactions that require large sample sizes and address the effects of different exposures across time, geographical regions and socioeconomic status.
Knowledge, attitudes and practices (KAP) of the population regarding severe fever with thrombocytopenia syndrome (SFTS) in endemic areas of Lu'an in China were assessed before and after an intervention programme. The pre-intervention phase was conducted using a sample of 425 participants from the 12 selected villages with the highest rates of endemic SFTS infection. A predesigned interview questionnaire was used to assess KAP. Subsequently, an intervention programme was designed and applied in the selected villages. KAP was re-assessed for each population in the selected villages using the same interview questionnaire. Following 2 months of the programme, 339 participants had completed the re-assessed survey. The impact of the intervention programme was evaluated using suitable statistical methods. A significant increase in the KAP and total KAP scores was noted following the intervention programme, whereas the proportion of correct knowledge, the positive attitudes and the effective practices toward SFTS of respondents increased significantly. The intervention programme was effective in improving KAP level of SFTS in populations that were resident in endemic areas.
An outbreak of acute hepatitis recently occurred in a nursing home in Zhejiang Province, China. The objectives of this study were to confirm the outbreak and identify the aetiology, source and transmission patterns. All residents and staff in or near the nursing home during the period from 1 October 2014 to 21 May 2015 were investigated regarding hygiene and for epidemiological information including water and food (eating meat especially pork products). Serum and stool specimens were collected for detection of hepatitis E virus (HEV) antibodies using ELISA and RNA using RT–PCR. Samples that were RNA positive were genotyped. Of 185 senior residents and 24 staff in the nursing home, there were 37 laboratory-confirmed cases during the outbreak. Of these cases, 12 patients (three deaths) were symptomatic with jaundice, a common clinical symptom for hepatitis E infection. HEV strains were isolated from three cases and they formed a single cluster within genotype 4d. A case-control study was conducted to investigate potential risk factors for the outbreak and the results revealed that cases more often washed their dishes and rinsed their mouths using tap water than the controls (P < 0·05). Based on hygiene investigation and meteorological information, it is likely that HEV-infected sewage and faeces contaminated the water network on rainy days. Collectively, these results suggest that the outbreak of HEV genotype 4 infection was most likely caused by contaminated tap water rather than food.
While radiocarbon is widely applied in dating ancient samples, recent studies reveal that 14C concentrations in modern samples can also yield precise ages due to the atmospheric testing of thermonuclear devices between 1950 and 1963. 14C concentrations in both enamel and organic matter of 13 teeth from 2 areas in China were examined to evaluate and improve this method of forensic investigation. Choosing enamel near the cervix of the tooth can reduce the error caused by the difference between the sample formation time and whole enamel formation time because tooth enamel formations take a long time to complete. A proper regional data set will be helpful to get an accurate result when calculating the age of the sample (T1) by the CALIBomb program. By subtracting the enamel formation time (t), the birth date of an individual (T2) can be confirmed by enamel F14C from 2 teeth formed at different ages. Calculated enamel formation dates by 14C concentration are basically consistent with corresponding actual values, with a mean error of 1.9 yr for all results and 0.2 yr for the samples formed after AD 1960. This method is more effective for dating samples completed after AD 1960. We also found that 14C concentrations in organic matter of tooth roots are much lower than atmospheric concentrations in root formation years, suggesting that the organic material keeps turning over even after tooth formation is complete. This might be a potential tool for identification of death age to extract a proper component for 14C dating. We also observed that δ13C values between hydroxyapatite and organic matter indicate that isotopic fractionation during the biomineralization is 8–9%‰ more positive in mineral fractions than in organic matter.
Major depressive disorder (MDD) is moderately heritable, however genome-wide association studies (GWAS) for MDD, as well as for related continuous outcomes, have not shown consistent results. Attempts to elucidate the genetic basis of MDD may be hindered by heterogeneity in diagnosis. The Center for Epidemiological Studies Depression (CES-D) scale provides a widely used tool for measuring depressive symptoms clustered in four different domains which can be combined together into a total score but also can be analysed as separate symptom domains.
We performed a meta-analysis of GWAS of the CES-D symptom clusters. We recruited 12 cohorts with the 20- or 10-item CES-D scale (32 528 persons).
One single nucleotide polymorphism (SNP), rs713224, located near the brain-expressed melatonin receptor (MTNR1A) gene, was associated with the somatic complaints domain of depression symptoms, with borderline genome-wide significance (pdiscovery = 3.82 × 10−8). The SNP was analysed in an additional five cohorts comprising the replication sample (6813 persons). However, the association was not consistent among the replication sample (pdiscovery+replication = 1.10 × 10−6) with evidence of heterogeneity.
Despite the effort to harmonize the phenotypes across cohorts and participants, our study is still underpowered to detect consistent association for depression, even by means of symptom classification. On the contrary, the SNP-based heritability and co-heritability estimation results suggest that a very minor part of the variation could be captured by GWAS, explaining the reason of sparse findings.
Mangrove ecosystems are highly productive and play an important role in tropical and global coastal carbon (C) budgets. However, sedimentary organic carbon (SOC) storage and turnover in mangrove forests are still poorly understood. Based on C isotopic measurements of sediment cores of 2 mangrove stands in southern China, SOC density was 431.77 Mg ha−1 at site 1 (a Aegiceras corniculatum-dominated high tidal stand) and 243.65 Mg ha−1 in site 2 (a Bruguiera gymnorrhiza + Kandelia candel-dominated middle tidal stand). SOC δ13C values at both mangrove sites ranged from -29.4% to −26.0%. SOC δ13C was enriched with depth at 20–50 cm at site 1, which possibly resulted from preferential microbial decomposition. SOC δ13C at site 2 experienced frequent tidal flushing, and presented relatively stable values with depth. A bomb-14C-based SOC turnover model indicated that turnover times of SOC at 20–50 cm at site 1 were 4.44–26.04 yr. Modern C input from abundant roots might account for the very short SOC turnover times at these subsurface layers. As a result, our study suggested that tidal processes had a great influence on SOC storage and turnover in mangrove forests.
A trend toward greater body size in dizygotic (DZ) than in monozygotic (MZ) twins has been suggested by some but not all studies, and this difference may also vary by age. We analyzed zygosity differences in mean values and variances of height and body mass index (BMI) among male and female twins from infancy to old age. Data were derived from an international database of 54 twin cohorts participating in the COllaborative project of Development of Anthropometrical measures in Twins (CODATwins), and included 842,951 height and BMI measurements from twins aged 1 to 102 years. The results showed that DZ twins were consistently taller than MZ twins, with differences of up to 2.0 cm in childhood and adolescence and up to 0.9 cm in adulthood. Similarly, a greater mean BMI of up to 0.3 kg/m2 in childhood and adolescence and up to 0.2 kg/m2 in adulthood was observed in DZ twins, although the pattern was less consistent. DZ twins presented up to 1.7% greater height and 1.9% greater BMI than MZ twins; these percentage differences were largest in middle and late childhood and decreased with age in both sexes. The variance of height was similar in MZ and DZ twins at most ages. In contrast, the variance of BMI was significantly higher in DZ than in MZ twins, particularly in childhood. In conclusion, DZ twins were generally taller and had greater BMI than MZ twins, but the differences decreased with age in both sexes.
For over 100 years, the genetics of human anthropometric traits has attracted scientific interest. In particular, height and body mass index (BMI, calculated as kg/m2) have been under intensive genetic research. However, it is still largely unknown whether and how heritability estimates vary between human populations. Opportunities to address this question have increased recently because of the establishment of many new twin cohorts and the increasing accumulation of data in established twin cohorts. We started a new research project to analyze systematically (1) the variation of heritability estimates of height, BMI and their trajectories over the life course between birth cohorts, ethnicities and countries, and (2) to study the effects of birth-related factors, education and smoking on these anthropometric traits and whether these effects vary between twin cohorts. We identified 67 twin projects, including both monozygotic (MZ) and dizygotic (DZ) twins, using various sources. We asked for individual level data on height and weight including repeated measurements, birth related traits, background variables, education and smoking. By the end of 2014, 48 projects participated. Together, we have 893,458 height and weight measures (52% females) from 434,723 twin individuals, including 201,192 complete twin pairs (40% monozygotic, 40% same-sex dizygotic and 20% opposite-sex dizygotic) representing 22 countries. This project demonstrates that large-scale international twin studies are feasible and can promote the use of existing data for novel research purposes.
Active symptom surveillance was applied to three selected communities ( 160 147 persons) in Tianjin from 2010 to 2012. We examined 1089 individuals showing pertussis-like symptoms, of which 1022 nasopharyngeal specimens were tested for pertussis by polymerase chain reaction and 802 sera for anti-pertussis toxin antibodies. Of the total cases tested, 113 were confirmed, and their demographic, clinical, and vaccination-related data were collected. The annual incidence was 23·52 cases/100 000 persons among communities, which was 16·22 times that obtained via hospital reports for the same period (P < 0·001). The actual incidence in the 15–69 years age group was most significantly underestimated by hospitals, given that it was 43·08 times that of the reported hospital rate. Among the cases aged <15 years, 84·5% were individuals who had been fully vaccinated. The misdiagnosis rate was as high as 94·69%, and only 5·31% of the confirmed pertussis cases were properly diagnosed as pertussis at their first medical visit. Pertussis incidence in China has been severely underestimated and this was in part due to a high misdiagnosis rate. Adolescents and adults have become new high-risk populations. Future work should focus on reinforcing immunization programmes, especially among adolescents and adults.
Severe fever with thrombocytopenia syndrome virus (SFTSV) has been prevalent for some time in China and it was first identified in 2010. However, the seroprevalence of SFTSV in the general population in southeastern China and risk factors associated with the infection are currently unclear. Blood samples were collected from seven counties across Zhejiang province and tested for the presence of SFTSV-specific IgG antibodies by ELISA. A total of 1380 blood samples were collected of which 5·51% were seropositive for SFTSV with seroprevalence varying significantly between sites. Seroprevalence of SFTSV in people who were family members of the patient, lived in the same village as the patient, or lived in a different village than the patient varied significantly. There was significant difference in seroprevalence between participants who bred domestic animals and participants who did not. Domestic animals are probably potential reservoir hosts and contact with domestic animals may be a transmission route of SFTSV.
Chemical action between cyclodextrins (CDs) and TOPO-(CdSe)ZnS quantum dots (QDs) generates a water-soluble solution of CD-QDs. Hydrophobic TOPO molecules on surface of the QDs are compatible to thread through the pockets of CDs and make the hydroxyl group on end of CDs to approach the ZnS surface, and then cause the interaction between ZnS and the hydroxyls. In this paper, Photoluminescence of the γ-CD-QD solution appeared about 15 nm of red movement compared with that of the QDs in hexane; 58% replacement of the crystal coordinate bond of Zn-S with that of Zn-O in the ZnS shell was demonstrated by using first-principles density functional theory and the red shift of the photoluminescence of CD-QDs; and –0.11eV of the energy gain of the exchange model was calculated by using an effective mass (EM) model. CD-QDs will provide water-soluble QDs with conjugational group for biology and molecule-device applications.
Electroactive polymers (EAPs) are capable of converting energy in the form of electric charge and voltage to mechanical force and movement and vice versa. Several electroactive polymer actuator materials whose responses are controlled by external electric fields, e.g. poly(vinylidene fluoride-trifluoroethylene) based fluoroterpolymers, have generated considerable interest for use in applications such as artificial muscles, sensors, parasitic energy capture, integrated bio-microelectromechanical systems (BioMEMS) and microfluidic devices due to their high electric-field induced strain, high elastic modulus, high electromechanical coupling and high frequency operation, etc. Scaling the EAP down into microsystems is one of the promising trends of EAP actuators and sensors especially for biomedical engineering. The combination of micro-optics and integrated BioMEMS, referred to as bio-micro-opto-electromechanical systems (BioMOEMS), makes a new opportunity for innovation in the EAP field. We present an approach to the fabrication of low-cost, large-stroke deformable micromirrors based on high performance electroactive polymer film microactuator arrays. Integrated Optic-BioMEMS based on electroactive polymer deformable micromirror (EAPDM) technology provide potential applications in biomedical optics such as ophthalmology (retinal imaging and vision care) and cancer detection and treatment.
Nanostructures, such as nanowires, nanotubes, and nanocoils, can be described in many cases as quasi one-dimensional (1D) curved objects projecting in three-dimensional (3D) space. A parallax method to reconstruct the correct three-dimensional geometry of such 1D nanostructures is presented. A series of images were acquired at different view angles, and from those image pairs, 3D representations were constructed using a MATLAB program. Error analysis as a function of view-angle between the two images is discussed. As an example application, we demonstrate the importance of knowing the true 3D shape of Boron nanowires. Without precise knowledge of the nanowire's dimensions, diameter and length, mechanical resonance data cannot be properly fit to obtain an accurate estimate of the Young's modulus.
High quality optical waveguides have been fabricated from fluorinated poly(arylene ether ketone) materials using a standard photolithographic process. Fabrication of waveguide devices on a polymer substrate is described, including a method of end-facet preparation using excimer laser micromachining. Material issues affecting waveguide birefringence and device performance are discussed.
Internal friction and modulus in YBa2Cu3Oy, which are related to flux pinning, were examined by means of the vibrating reed technique before and after the slow neutron irradiation to different fluences. Both the decrease of mechanical dissipation and the increase of the modulus associated with strongly enhanced flux pinning were observed in a sample irradiated up to a suitable fluence. However, a decrease of modulus and magnetic hysteresis loop was found after further irradiation. A change in the microstructure of the irradiated material is used to explain the observed phenomena.
Before copper will be used in the manufacture of microelectronic circuits, a number of its surface and interface properties have to be addressed. These include corrosion resistance, adhesion to dielectrics, and ability to block the transport of copper ions from the metal into adjacent materials. Different schemes have been explored to meet copper's material properties needed for electronic application. For surface modification, these include ion implantation, plasma treatments, formation of surface silicides, and annealing of copper films doped with other elements. For interface control, most schemes have involved deposition of an adhesion/barrier film. The present paper will discuss our present understanding of the mechanisms that govern surface and interface passivation. Special attention will be given to schemes that might lead to both surface and interface passivation in the same process.
Copper is being investigated for application as multi-level interconnection metal in silicon ultra-large-scale integration (ULSI). On the other hand, COSi2 is being tested for application as contacts in sub-half micron ULSI circuits. Copper will thus be used on COSi2 to bring the electrical connection to the outside world. In this investigation we have therefore studied the interactions of copper with CoSi2 employing sheet resistance measurements (four-point probe), Rutherford back scattering (RBS), and X-ray diffraction (XRD). In addition the stability of the Schottky diodes, n-Si/CoS2/Cu, has been investigated as a function of the heat treatment in the range of room temperature to 600° C in argon-3% hydrogen mixture gas ambient. Both the measurements of the analytical and electrical characteristics show that Cu on n-Si/CoSi2 is stable at least up to a 30 minutes anneal at 600°C in argon-3% hydrogen medium. These results will be presented and discussed.
Oxidation kinetics of plasma-assisted chemical vapor deposited (PA-CVD) copper films were investigated using Rutherford backscattering spectrometry (RBS). The PA-CVD copper films were deposited using hydrogen plasma reduction of bis(hexafluoroacetylacetonato) copper(II), Cu(hfa)2, precursor. Under identical experimental conditions, PA-CVD copper films oxidize more slowly than sputtered copper films. This decrease in oxidationis manifested both as a time delay at the beginning of the oxidation of the PA-CVD copper films and as a decrease in the rate of oxide growth at oxidation temperatures of 200ºC and below. The possivation appears to be caused by the hydrogen plasma present during depostion.
Thermal and irradiation induced intermixing of uranium suicide reactor fuels with the aluminum cladding is an important consideration in understanding their fission gas and fuel swelling behavior. We have used Rutherford backscattering to follow the behavior of an Al thin film on U3Si and U3Si2 during 1.5 MeV Kr ion irradiation at temperatures of 30 and 350°C. After an initial dose during which no intermixing occurs, the Al mixes quickly into U3Si. The threshold dose is believed to be associated with an oxide layer between the Al and the uranium suicide. At 300°C and doses greater than threshold, rates of mixing and aluminide phase growth are extracted.