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We present the third data release from the Parkes Pulsar Timing Array (PPTA) project. The release contains observations of 32 pulsars obtained using the 64-m Parkes ‘Murriyang’ radio telescope. The data span is up to 18 yr with a typical cadence of 3 weeks. This data release is formed by combining an updated version of our second data release with $\sim$3 yr of more recent data primarily obtained using an ultra-wide-bandwidth receiver system that operates between 704 and 4032 MHz. We provide calibrated pulse profiles, flux density dynamic spectra, pulse times of arrival, and initial pulsar timing models. We describe methods for processing such wide-bandwidth observations and compare this data release with our previous release.
The association between dietary Cu intake and mortality risk remains uncertain. We aimed to investigate the relationship of dietary Cu intake with all-cause mortality among Chinese adults. A total of 17 310 participants from the China Health and Nutrition Survey, a national ongoing open cohort of Chinese participants, were included in the analysis. Dietary intake was measured by three consecutive 24-h dietary recalls in combination with a weighing inventory over the same 3 d. The average intakes of the 3-d dietary macronutrients and micronutrients were calculated. The study outcome was all-cause mortality. During a median follow-up of 9·0 years, 1324 (7·6 %) participants died. After adjusting for sex, age, BMI, ever alcohol drinking, ever smoking, education levels, occupations, urban or rural residents, systolic blood pressure, diastolic blood pressure and the intakes of fat, protein and carbohydrate, the association between dietary Cu intake and all-cause mortality followed a J-shape (Pfor nonlinearity = 0·047). When dietary Cu intake was assessed as quartiles, compared with those in the first quartile (<1·60 mg/d), the adjusted hazard ratios for all-cause mortality were 0·87 (95 % CI (0·71, 1·07)), 0·98 (95 % CI (0·79, 1·21)) and 1·49 (95 % CI (1·19, 1·86)), respectively, in participants in the second (1·60–<1·83 mg/d), third (1·83–<2·09 mg/d) and fourth (≥2·09 mg/d) quartiles. A series of subgroup analyses and sensitivity analyses showed similar results. Overall, our findings emphasised the importance of maintaining optimal dietary Cu intake levels for prevention of premature death.
Since December 2019, China has experienced a widespread outbreak of COVID-19. However, at the early stage of outbreak, investigations revealed a variety of patterns resulting in the transmission of COVID-19. Thus, it is essential to understand the transmission types and the potential for sustained human-to-human transmission. Moreover, the information regarding the characteristics of transmission helps in coordinating the current screening programme, and controlling and containing measures, and also, helps in deciding the appropriate quarantine duration. Thus, this investigation reports an outbreak of COVID-19 in a family residing in Wenzhou, Zhejiang, China during the month of January−February 2020.
The antibacterial hydrogels can be widely used in the biomedical area owing to their excellent properties. The main limitation of antibacterial hydrogels is their poor mechanical strength. In this study, the novel hydrogels were fabricated with a mixture of silk fibroin (SF), chitosan (CH), agarose (AG), and silver nanoparticles (SNPs) via facile reaction condition without inorganic substances. The mechanical property of these fabricated hydrogels can be modulated by the concentration of SF or AG. The rheological studies demonstrated enhanced elasticity of CH-doped hydrogels. Because of the presence of CH and Ag in hydrogels, the antimicrobial property against gram-positive and gram-negative bacteria was exhibited. Cytocompatibility test proved the very low toxic nature of the hydrogels. In addition, these composite hydrogels have a smaller porosity, higher swelling ratio, and good compatibility, indicating their great potential for biomedical application.
Simple sequence repeat (SSR) analysis was performed on five Secale species, four Triticum species and a Triticale line Fenzhi-1 using 102 pairs of microsatellite primers. A 387-bp specific DNA fragment FZ387 (GenBank accession no. EF179137) was obtained from the Triticale Fenzhi-1 with primer Xgwm614, without amplification in Secale. NCBI BLAST revealed that this FZ387 sequence had 94% and 95% similarity to part of the Gypsy Ty3-LTR retrotransposon Fatima in Triticum monoccocum (AY485644) and Triticum turgidum (AY494981), respectively. A pair of specific polymerase chain reaction (PCR) primers, FaF and FaR, was designed based on the conserved region of this FZ387 sequence. The amplification of primer pair Xgwm614F and FaR revealed that a specific 350-bp band (designation as A350) was obtained from the species containing A chromosomes. Furthermore, PCR on Langdon Chinese Spring substitution lines was performed, and the results found that this segment was located on both long and short arms of all A chromosomes. However, the amplification of primer pair FaF and Xgwm614R gave rise to a specific DNA band of about 350 bp (designated AB350) from materials containing A and/or B chromosomes. The wild species of wheat and the relatives were amplified using the two pairs of primers, and revealed that only A350 and AB350 were found in Chinese Spring (CS). Sequence comparison and variation of SSR primers binding regions of FZ387 indicated that significant diversity might exist in the internal sequence of this Fatima-like element among triticeae genomes. Meanwhile, both A350 and AB350 can be used as molecular markers for the detection of A and AB genomes.
Molecular dynamics simulations with Tersoff potentials
were used to study the tensile and compressive mechanical behavior of SiC
nanowires with torsion strain. The simulation results show that small
torsion strain does not affect the mechanical behavior of SiC nanowires.
However, large torsion strain induces the decrease of the critical stress.
With large torsion strain, the collapse occurs in the nanowires before
tensile failure and compressive buckling, and deformation zone occurs in the
A novel stearic acid (SA)/3-aminopropyltrethoxysilane (APS) composite structure was fabricated using the combined method of the Langmuir–Blodgett technique and self-assembly monolayer (SAM) technique. Its frictional, adhesive properties and interface contact types between the atomic force microscope tip and the samples were evaluated based on Amonton’s laws and the general Carpick’s transition equation, respectively. The results showed that the tip–sample contacts corresponded to the Johnson–Kendall–Robert/Derjaguin–Muller–Toporov (DMT) transition model for SiO2, APS-SAMs, and the unheated SA-APS composite structure, and for the heated SA-APS bilayer to the DMT model. Frictional forces for the four samples were linearly dependent on external loads at higher loads, and at lower loads they were significantly affected by adhesive forces. Frictional and scratching tests showed that the heated SA-APS composite structure exhibited the best lubricating properties and adhesion resistance ability, and its wear resistance capacity was greatly improved due to the binding-mode conversion from hydrogen bonds to covalent bonds. Thus, this kind of composite bilayer might be promising for applications in the lubrication of nano/microelectromechanical systems.
Pure vapor-grown carbon nanofibers (VGCNF's) with controllable diameters of 10–200 nm were prepared by an improved floating catalyst method. Through transmission electron microscopy (TEM) observation, it was found that VGCNF's have a duplex structure, a hollow and high-crystallinity graphite filament called primary carbon fiber surrounded by a pyrocarbon layer with low graphite crystallinity. It was observed using high-resolution TEM that VGCNF's have excellent graphitic crystallinity with graphite layers stacked neatly parallel to fiber axis. Moreover, x-ray diffraction results showed that the graphitic crystallinity of carbon fibers became higher with decreasing diameter of carbon fibers.
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