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The search for life in the Universe is a fundamental problem of astrobiology and modern science. The current progress in the detection of terrestrial-type exoplanets has opened a new avenue in the characterization of exoplanetary atmospheres and in the search for biosignatures of life with the upcoming ground-based and space missions. To specify the conditions favourable for the origin, development and sustainment of life as we know it in other worlds, we need to understand the nature of global (astrospheric), and local (atmospheric and surface) environments of exoplanets in the habitable zones (HZs) around G-K-M dwarf stars including our young Sun. Global environment is formed by propagated disturbances from the planet-hosting stars in the form of stellar flares, coronal mass ejections, energetic particles and winds collectively known as astrospheric space weather. Its characterization will help in understanding how an exoplanetary ecosystem interacts with its host star, as well as in the specification of the physical, chemical and biochemical conditions that can create favourable and/or detrimental conditions for planetary climate and habitability along with evolution of planetary internal dynamics over geological timescales. A key linkage of (astro)physical, chemical and geological processes can only be understood in the framework of interdisciplinary studies with the incorporation of progress in heliophysics, astrophysics, planetary and Earth sciences. The assessment of the impacts of host stars on the climate and habitability of terrestrial (exo)planets will significantly expand the current definition of the HZ to the biogenic zone and provide new observational strategies for searching for signatures of life. The major goal of this paper is to describe and discuss the current status and recent progress in this interdisciplinary field in light of presentations and discussions during the NASA Nexus for Exoplanetary System Science funded workshop ‘Exoplanetary Space Weather, Climate and Habitability’ and to provide a new roadmap for the future development of the emerging field of exoplanetary science and astrobiology.
Triploid and pentaploid breeding is of great importance in agricultural production, but it is not always easy to obtain double ploidy parents. However, in fishes, chromosome ploidy is diversiform, which may provide natural parental resources for triploid and pentaploid breeding. Both tetraploid and hexaploid exist in Schizothorax fishes, which were thought to belong to different subfamilies with tetraploid Percocypris fishes in morphology, but they are sister genera in molecule. Fortunately, the pentaploid hybrid fishes have been successfully obtained by hybridization of Schizothorax wangchiachii (♀, 2n = 6X = 148) × Percocypris pingi (♂, 2n = 4X = 98). To understand the genetic and morphological difference among the hybrid fishes and their parents, four methods were used in this study: morphology, karyotype, red blood cell (RBC) DNA content determination and inter-simple sequence repeat (ISSR). In morphology, the hybrid fishes were steady, and between their parents with no obvious preference. The chromosome numbers of P. pingi have been reported as 2n = 4X = 98. In this study, the karyotype of S. wangchiachii was 2n = 6X = 148 = 36m + 34sm + 12st + 66t, while that the hybrid fishes was 2n = 5X = 123 = 39m + 28sm + 5st + 51t. Similarly, the RBC DNA content of the hybrid fishes was intermediate among their parents. In ISSR, the within-group genetic diversity of hybrid fishes was higher than that of their parents. Moreover, the genetic distance of hybrid fishes between P. pingi and S.wangchiachii was closely related to that of their parental ploidy, suggesting that parental genetic material stably coexisted in the hybrid fishes. This is the first report to show a stable pentaploid F1 hybrids produced by hybridization of a hexaploid and a tetraploid in aquaculture.
Rabies is one of the major public health problems in China, and the mortality rate of rabies remains the highest among all notifiable infectious diseases. A meta-analysis was conducted to investigate the post-exposure prophylaxis (PEP) vaccination rate and risk factors for human rabies in mainland China. The PubMed, Web of Science, Chinese National Knowledge Infrastructure, Chinese Science and Technology Periodical and Wanfang databases were searched for articles on rabies vaccination status (published between 2007 and 2017). In total, 10 174 human rabies cases from 136 studies were included in this meta-analysis. Approximately 97.2% (95% confidence interval (CI) 95.1–98.7%) of rabies cases occurred in rural areas and 72.6% (95% CI 70.0–75.1%) occurred in farmers. Overall, the vaccination rate in the reported human rabies cases was 15.4% (95% CI 13.7–17.4%). However, among vaccinated individuals, 85.5% (95% CI 79.8%–83.4%) did not complete the vaccination regimen. In a subgroup analysis, the PEP vaccination rate in the eastern region (18.8%, 95% CI 15.9–22.1%) was higher than that in the western region (13.3%, 95% CI 11.1–15.8%) and this rate decreased after 2007. Approximately 68.9% (95% CI 63.6–73.8%) of rabies cases experienced category-III exposures, but their PEP vaccination rate was 27.0% (95% CI 14.4–44.9%) and only 6.1% (95% CI 4.4–8.4%) received rabies immunoglobulin. Together, these results suggested that the PEP vaccination rate among human rabies cases was low in mainland China. Therefore, standardised treatment and vaccination programs of dog bites need to be further strengthened, particularly in rural areas.
Accurate prediction of the flow around multi-element airfoil is a prerequisite for improving aerodynamic performance, but its complex flow features impose high demands on turbulence modeling. In this work, delayed detached-eddy-simulation (DDES) and zonal detached-eddy-simulation (ZDES) was applied to simulate the flow past a three-element airfoil. To investigate the effects of numerical dissipation of spatial schemes, the third-order MUSCL and the fifth-order interpolation based on modified Roe scheme were implemented. From the comparisons between the calculations and the available experimental result, third-order MUSCL-Roe can provide satisfactory mean velocity profiles, but the excessive dissipation suppresses the velocity fluctuations level and eliminates the small-scale structures; DDES cannot reproduce the separation near the trailing edge of the flap which lead to the discrepancy in mean pressure coefficients, while ZDES result has better tally with the experiment.
Rural-to-urban migrant workers are a large marginalised population in urban China. Prevalence estimates of common mental health problems (CMHPs) in previous studies varied widely and very few studies have investigated migration-related factors of CMHPs in migrant workers. The objective of this study was to determine the prevalence and risk factors of CMHPs among Chinese migrant workers.
A random sample of 3031 migrant workers of ten manufacturing factories in Shenzhen, China, completed a standardised questionnaire containing socio-demographic and migration-related variables and the Chinese 12-item General Health Questionnaire (GHQ-12). A GHQ-12 score of three or higher was used to denote the presence of CMHPs.
The prevalence of CMHPs was 34.4% in Chinese migrant workers. In multiple logistic regression, risk factors for CMHPs included being 16–25 years old (odd ratio [OR] 1.65, 95% confidence interval [CI] 1.28, 2.12), being 26–35 years old (OR 1.36, 95% CI: 1.05, 1.75), low monthly income (OR 1.42, 95% CI 1.04, 1.92), poor living condition (OR: 1.76, 95% CI: 1.22, 2.54), physical illness in the past 2 weeks (OR 1.72, 95% CI 1.43, 2.05), having worked in many cities (OR 1.34, 95% CI 1.03, 1.74), infrequently visiting hometown (OR 1.56, 95% CI 1.22, 1.99), poor Mandarin proficiency (OR 1.51, 95%CI 1.13, 2.01), a low level of perceived benefits of migration (OR 1.33, 95% CI 1.14, 1.55) and working more than 8 h/day (OR 1.39, 95% CI 1.14, 1.70).
CMHPs are very prevalent among Chinese migrant workers. Given the large number of Chinese migrant workers, there is an urgent need to address the mental health burden of China's migrant worker population.
Insect defensins, are cationic peptides that play an important role in immunity against microbial infection. In the present study, an anionic defensin from Plutella xylostella, (designated as PxDef) was first cloned and characterized. Amino acid sequence analysis showed that the mature peptide owned characteristic six-cysteine motifs with predicted isoelectric point of 5.57, indicating an anionic defensin. Quantitative real-time polymerase chain reaction analysis showed that PxDef was significantly induced in epidermis, fat body, midgut and hemocytes after injection of heat-inactivated Bacillus thuringiensis, while such an induction was delayed by the injection of live B. thuringiensis in the 4th instar larvae of P. xylostella. Knocking down the expression of nuclear transcription factor Dorsal in P. xylostella by RNA interference significantly decreased the mRNA level of PxDef, and increased the sensitivity of P. xylostella larvae to the infection by live B. thuringiensis. The purified recombinant mature peptide (PxDef) showed higher activity against Gram-positive bacteria, with the minimum inhibition concentrations of 1.6 and 2.6 µM against B. thuringiensis and Bacillus subtilis, respectively. To our knowledge, this is the first report about an anionic PxDef, which may play an important role in the immune system of P. xylostella against B. thuringiensis.
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.
Crop nitrogen (N) status is an important indicator of crop health and predictor of subsequent crop yield. The present study was conducted to analyse the relationships between nitrogen nutrition index (NNI), nitrogen biomass difference (ΔNB) and spectral indices in wheat, and then attempt to improve field N management. Spectral indices and concurrent sample N and biomass parameters were obtained from the Shihezi University experimental site in Xinjiang, China during 2009 and 2010. The results showed that all spectral indices were significantly correlated with NNI. Regression functions with the highest determination coefficient (R2) and the lowest root mean square error (RMSE) were used to improve prediction of NNI, and then the selected spectral index was used to estimate NNI and ΔNB. The strongest relationships were observed for the products of modified normalized difference 705 × biomass dry weight (BND705) and the enhanced vegetation index 2 (EVI2) for estimating NNI. There were also strong relationships between the NNI and the normalized NNI (ΔNNI) as well as between ΔNNI and ΔNB, with a linear relationship between ΔNB and the spectral index BND705 and a linear relationship between ΔNB and the spectral index EVI2. These results indicated that BND705 and EVI2 can be used to improve the accuracy of NNI estimation, and the correlations of ΔNB and NNI with BND705 and EVI2 can be used to further improve field N management in wheat.
We use 4 broadband SEDs spanning 7 years to study the spectral shape and long term variability of RE J2248-511: an unusual AGN discovered in the extreme-UV by the ROSAT Wide Field Camera. This implies a large ultrasoft X-ray flux, which is typical of narrow-line Seyfert 1s, yet its optical lines are clearly broader than the NLS1 definition allows. Here we show that the continuum SED for the brightest epoch dataset is consistent with the mean SED of a standard quasar, and matches well to that from an XMM–SDSS sample of AGN with M/M⊙ ~ 108 and L/LEdd ~ 0.2. All the correlated optical and soft X-ray variability can be due entirely to a major absorption event. The only remarkable aspect of this AGN is that there is no measurable intrinsic X-ray absorption column in the brightest epoch dataset. The observed FUV flux is determined by the combination of this and the fact that the source lies within a local absorption hole. RE J2248-511, which once defied classification, demonstrates that characterisation of such objects requires multi-epoch, multi-wavelength campaigns.
This study aimed to confirm that vertical transmission of hepatitis B virus (HBV) can occur via the infected ovum. Specimens studied were obtained from discarded test-tube embryos from mothers with chronic HBV infection who had received in vitro fertilization treatment. Single-cell reverse transcriptase–polymerase chain reaction was used to detect HBV mRNA in the embryos. HBV mRNA was detected in the cleavage embryos of patients with chronic HBV infection, with a detection rate of 13·2% (5/38). The level of serum HBV DNA was not related to the HBV mRNA positivity rates in embryos. In this study, HBV mRNA was detected in test-tube embryos from HBV-infected mothers who had received in vitro fertilization treatment. This confirms the theory of vertical transmission of HBV via the ovum, thereby providing an important theoretical basis for further study on the mechanism of HBV vertical transmission, influencing factors and blocking measures.
The objective of this study was to quantify the effectiveness of selected surgical masks in arresting vegetative cells and endospores in an experimental model that simulated contagious patients.
Five commercially available surgical masks were tested for their ability to arrest infectious agents. Surgical masks were placed over the nose and mouth of mannequin head forms (Simulaids adult model Brad CPR torso). The mannequins were retrofitted with a nebulizer attached to an automated breathing simulator calibrated to a tidal volume of 500 mL/breath and a breathing rate of 20 breaths/min, for a minute respiratory volume of 10 L/min. Aerosols of endospores or vegetative cells were generated with a modified microbiological research establishment-type 6-jet collision nebulizer, while air samples were taken with all-glass impinger (AGI-30) samplers downstream of the point source. All experiments were conducted in a horizontal bioaerosol chamber.
Mean arrestance of bioaerosols by the surgical masks ranged from 48% to 68% when the masks were challenged with endospores and from 66% to 76% when they were challenged with vegetative cells. When the arrestance of endospores was evaluated, statistical differences were observed between some pairs, though not all, of the models evaluated. There were no statistically significant differences in arrestance observed between models of surgical masks challenged with vegetative cells.
The arrestance of airborne vegetative cells and endospores by surgical masks worn by simulated contagious patients supports surgical mask use as one of the recommended cough etiquette interventions to limit the transmission of airborne infectious agents.
We designed and produced pure cubic zirconia (ZrO2) ceramic1
coatings by an ion beam assisted deposition (IBAD) with nanostructures
comparable to the size of proteins. Our ceramic coatings exhibit high
hardness and a zero contact angle with serum. In contrast to hydroxyapatite
(HA), nano-engineered zirconia films possess excellent adhesion to all
orthopaedic materials. Cell adhesion and proliferation experiments were
performed with a bona fide mesenchymal stromal cell line (OMA-AD). Our
experimental results indicate that the nano-engineered cubic zirconia is
superior in supporting growth, adhesion, and proliferation. Since cell
attachment is mediated by adhesive proteins such as fibronectin (FN), to
elucidate why cells attach more effectively to our nanostructures, we
performed a comparative analysis of adsorption energies of FN fragment using
quantum mechanical calculations and Monte Carlo (MC) simulation both on
smooth and nanostructured surfaces. We have found that a FN fragment adsorbs
significantly stronger on the nanostructured surface than on the smooth
Recently, an inexpensive 3D lithography technique was developed by Professor
Nicholas Fang at the University of Illinois where a projector is used in
combination with a Microsoft® PowerPoint presentation to expose the liquid
negative-tone photoresist 1,6-hexanediol diacrylate in a layer-by-layer
fashion. Where Professor Fang initially used this method as a teaching tool,
we have used the inexpensive 3D printing technique to create 3D structures
of fumarate based polymers. This class of polymers are liquids at room
temperature which makes them ideal for the projector based lithography
technique when used in combination with the photoinitiator
bisphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide (BAPO). Furthermore, the
fumarate based materials are biocompatible and are suitable candidates for
tissue engineering applications.
DNA is an anionic polyelectrolyte, which occupies a large volume in salt
free solution due to the coulomb repulsion between the charged groups. In
the presence of high valence cations, DNA condenses into nanoparticles. DNA
nanoparticles have generated a lot of interest as a preferred vehicle for
delivering therapeutic DNA in gene therapy. The efficiency of gene delivery
is determined by stability and compactness of the particles. However not
much is known about the organization of DNA within the particles. The large
polymer cations condense DNA rapidly, with no distinct intermediate stages
that give insight into the arrangement of DNA within the nanoparticle. In
our work, we form nanoparticles with short DNA strands to slow down the
condensation process. The polymer cation is polyethyleneimine with grafted
sugar moieties. Distinct intermediate stages are observed with Atomic Force
Microscopy. The assembly occurs via the formation of fiber condensates,
which appear to be the unit of DNA condensation. Nanoparticles form by
compaction of interweaving networks of fiber condensates.
Our overall intent is to develop improved electrically active prosthetic
devices to allow interactions between regenerated nerve fibers (axons) and
external electronics. To allow for infiltration of axons, these devices must
be highly porous. Additionally, they must exhibit selective and structured
conductivity to allow the connection of electrode sites with external
circuitry with tunable electrical properties that enable the transmission of
neural signals through physical connections to external circuitry (e.g.
through attached wires.) The chosen material must be biocompatible with
minimal irresolvable inflammatory response to allow intimate contact with
regenerated nerve tissue and mechanically compatible with the surrounding
We have utilized electrospinning and projection lithography as tools to
create conductive, porous networks of non-woven biocompatible fibers in
order to meet the materials requirements for the neural interface. The
biocompatible fibers were based on the known biocompatible material
poly(dimethyl siloxane) (PDMS) as well as a newer biomaterial material
developed in our laboratories, poly(butylene fumarate) (PBF). Both of the
polymers cannot be electrospun using conventional electrospinning techniques
due to their low glass transition temperatures, so in situ
crosslinking methodologies were developed to facilitate micro- and
nano-fiber formation during electrospinning. The conductivity of the
electrospun fiber mats was controlled by varying the loading with
multi-walled carbon nanotubes (MWNTs).
We report on the performance of a planetary multi-wafer MOCVD reactor which handles 5 six inch wafers simultaneously. The reactor is combined with a liquid delivery system which mixes the liquid precursors from three different sources: 0.35 molar solutions of Ba(thd)2 and Sr(thd)2 and a 0.4 molar solution of Ti(O-i-Pr)2(thd)2. The microstructure and the film stress were investigated by X-ray diffraction and the composition of the films was determined by X-ray fluorescence analysis. As a direct consequence of the reactor design we obtain a high uniformity of the films over 6 inch wafers, as well as high efficiencies for the precursor incorporation. Film growth is discussed within a wide parameter field and the finally achieved electrical properties, e.g., permittivity, loss tangent, leakage current, are discussed in relation to the microstructural properties.
Fluorescent dyes including Nile Red (NR), fluorescein, rhodamine and 4- (dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) derivatives were investigated to find an application for the organic light emitting device (OLED). Relationship between the molecular structure and optical property was calculated by ab initio (HF and DFT/6-31G*) and semiempirical (AM1/PM3 and INDO/S) calculation methods for the geometry optimization and for the information of electronic transition, respectively. The absorption maximum and the oscillator strength of molecules strongly depended on the molecular dipole moment, especially for the molecules having both strong electron donor and acceptor group. Since the calculated results were comparable with several experimental results, these semiempirical molecular orbital calculation methods could be used as a powerful prediction tool for optical properties of the luminescent molecules.