40 research outputs found
Antibacterial Activity and Physical Properties of Fish Gelatin-Chitosan Edible Films Supplemented with D-Limonene
Fish gelatin-chitosan edible films with D-limonene were successfully prepared, which exhibited exceptional mechanical properties and antimicrobial activity. It has been demonstrated that water-soluble chitosan, fish gelatin, and D-limonene could be a candidate precursor to prepare low cost and high-performance edible food packaging material. The results showed that D-limonene in the films could effectively resist the penetration of light and water because of its hydrophobicity. Moreover, the elongation at break (EAB) increased with the addition of D-limonene, which indicated that D-limonene served as a strong plasticizer for the film. Microscopic characterization showed that D-limonene was uniformly distributed in the as-prepared film. And we found that the film exhibited strong antibacterial activity against Escherichia coli (E. coli). All the results indicate that the as-prepared film could be a promising food packaging
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Anisotropic strength, deformation and failure of gneiss granite under high stress and temperature coupled true triaxial compression
The anisotropic mechanical behavior of rocks under high-stress and high-temperature coupled conditions is crucial for analyzing the stability of surrounding rocks in deep underground engineering. This paper is devoted to studying the anisotropic strength, deformation and failure behavior of gneiss granite from the deep boreholes of a railway tunnel that suffers from high tectonic stress and ground temperature in the eastern tectonic knot in the Tibet Plateau. High-temperature true triaxial compression tests are performed on the samples using a self-developed testing device with five different loading directions and three temperature values that are representative of the geological conditions of the deep underground tunnels in the region. Effect of temperature and loading direction on the strength, elastic modulus, Poisson's ratio, and failure mode are analyzed. The method for quantitative identification of anisotropic failure is also proposed. The anisotropic mechanical behaviors of the gneiss granite are very sensitive to the changes in loading direction and temperature under true triaxial compression, and the high temperature seems to weaken the inherent anisotropy and stress-induced deformation anisotropy. The strength and deformation show obvious thermal degradation at 200 °C due to the weakening of friction between failure surfaces and the transition of the failure pattern in rock grains. In the range of 25 °C–200 °C, the failure is mainly governed by the loading direction due to the inherent anisotropy. This study is helpful to the in-depth understanding of the thermal-mechanical behavior of anisotropic rocks in deep underground projects
Experimental Study on the Influence of Different Coal Species on Gas and Coal Dust Explosion
To further explore the propagation law of gas coal dust explosion with different coal species involved, 3 kinds of representative coal dust were tested in a self-made semi-enclosed pipe, and the flame propagation speed, flame surface luminescence intensity and maximum explosion pressure of gas coal dust explosion were studied. The results show that the maximum explosion pressure and flame propagation velocity of gas coal dust explosion rise first and then decrease with the increase of coal dust concentration, and there is an optimal gas concentration and coal dust concentration, which makes the flame propagation speed reach the maximum and the luminous intensity reach the maximum; flame propagation speed, the maximum explosion pressure and the luminous intensity produced by the explosion are reduced by lignite, bituminous coal and anthracite in turn
Construction and Analysis of a New Resting-State Whole-Brain Network Model
Background: Mathematical modeling and computer simulation are important methods for understanding complex neural systems. The whole-brain network model can help people understand the neurophysiological mechanisms of brain cognition and functional diseases of the brain. Methods: In this study, we constructed a resting-state whole-brain network model (WBNM) by using the Wendling neural mass model as the node and a real structural connectivity matrix as the edge of the network. By analyzing the correlation between the simulated functional connectivity matrix in the resting state and the empirical functional connectivity matrix, an optimal global coupling coefficient was obtained. Then, the waveforms and spectra of simulated EEG signals and four commonly used measures from graph theory and small-world network properties of simulated brain networks under different thresholds were analyzed. Results: The results showed that the correlation coefficient of the functional connectivity matrix of the simulated WBNM and empirical brain networks could reach a maximum value of 0.676 when the global coupling coefficient was set to 20.3. The simulated EEG signals showed rich waveform and frequency-band characteristics. The commonly used graph-theoretical measures and small-world properties of the constructed WBNM were similar to those of empirical brain networks. When the threshold was set to 0.22, the maximum correlation between the simulated WBNM and empirical brain networks was 0.709. Conclusions: The constructed resting-state WBNM is similar to a real brain network to a certain extent and can be used to study the neurophysiological mechanisms of complex brain networks
Large negative giant magnetoresistance at room temperature and electrical transport in cobalt ferrite-polyaniline nanocomposites
At room temperature, a large negative out-of-plane magnetoresistance (MR), [R(H)-R(0)]/R(0), with a value of −35.76% at magnetic field of 9 T has been obtained in the cobalt ferrite (CoFe2O4)/polyaniline (PANI) nanocomposites with CoFe2O4 loading of 40.0 wt% prepared by surface initiated polymerization (SIP) method, which is strongly related to the weak localization (WL) model in the weak disordered system. The negative MR at room temperature in the CoFe2O4/PANI nanocomposites exhibits the obvious nanoparticle loading and magnetic field dependent properties. Both thermal activated transport model and Mott variable range hopping (VRH) model are applied to express the electrical transport mechanism for the temperature regimes of 180–290 K and 50–180 K, accordingly. The electrical transport in the CoFe2O4/PANI nanocomposites obeys the 3D VRH transport mechanism at low temperature range of 50–180 K. The estimated activation energy Eg for the CoFe2O4/PANI nanocomposites with different CoFe2O4 nanoparticle loadings of 10.0, 20.0, 40.0, and 60.0 wt% is 61, 63, 65, and 87 meV, respectively. The coating of PANI on the surface of CoFe2O4 nanoparticle reveals the significant effect on both the remanence and coercivity of CoFe2O4 nanoparticle
Emergence of a novel GIII Getah virus variant in pigs in Guangdong, China, 2023
ABSTRACT From May to July of 2023, one pig farm in Heyuan city, Guangdong Province of China, suffered severe piglet death and sow reproductive disorders. The common pig viruses and bacteria tested negative. To uncover the possible cause of the disease, a metagenomic analysis was performed in the pooled small intestine samples from three 8-day-old diseased piglets. The results showed that Getah virus (GETV), an RNA virus, might be the potential pathogen that affects pig health. Subsequently, GETV nucleotide was detected in all of the 15 samples collected from three diseased piglets using quantitative reverse transcription PCR, suggesting GETV as the main pathogen of the disease. A GETV strain, designated as GDHYLC23, was successfully isolated using the swine testicle cell line. Sequence analysis showed that the epidemic strain had a unique 32-nucleotide repeat insertion in the 3′ noncoding region. Phylogenetic analysis showed that GDHYLC23 belonged to the pandemic group III. The identification of GETV with new variations implies the continuous evolution of the virus, which poses potential threats to the swine industry.IMPORTANCEPig farms are faced with emerging and re-emerging viruses that may cause substantial economic loss. The identification of potentially pathogenic viruses helps to prevent and control the spread of diseases. In this study, by using metagenomic analysis, we found that a neglected virus, GETV with a unique insertion in the genome, was the main pathogen in one pig farm that suffered severe piglet death and sow reproductive disorders. Although the potential impact of such an insertion on viral pathogenicity is unknown, the surveillance of the continuing evolution of GETV in pig farms cannot be ignored
Willingness to Be Circumcised for Preventing HIV among Chinese Men Who Have Sex with Men
Male circumcision can reduce the risk of HIV acquisition among heterosexual men, but its effectiveness is uncertain in men who have sex with men (MSM). Additionally, its acceptability among Chinese men is unknown given a lack of history and cultural norms endorsing neonatal and adult circumcision. This study evaluated the willingness to participate in a clinical trial of circumcision among 328 Chinese MSM. Some 11.6% respondents reported having been circumcised, most of them due to a tight foreskin. Of 284 uncircumcised MSM, 16.9% said they were absolutely willing to participate, 26.4% were probably, 28.9% were probably not, and 27.8% were absolutely not; 81% said male circumcision would help maintain genital hygiene. The major motivators for willingness to participate included contribution to AIDS scientific research and getting free medical service. Men also had concerns about ineffectiveness of circumcision in reducing HIV/sexually transmitted infection (STI) risks and side effects of the surgery. Those who did not have a Beijing resident card (adjusted odds ratio [AOR], 1.99; 95% confidence interval [CI], 1.17–3.38), did not find sexual partners through the Internet (AOR, 2.13; 95% CI, 1.21–3.75), and were not concerned about the effectiveness of circumcision (AOR, 2.37; 95% CI, 1.34–4.19) were more likely to be willing to participate in a trial. The study suggests that circumcision is uncommon among Chinese MSM. Considerable community education will be needed in circumcision advocacy among MSM in China. A clinical trial for efficacy among MSM should be considered