317 research outputs found
Origins of Large Voltage Hysteresis in High Energy-Density Metal Fluoride Lithium-Ion Battery Conversion Electrodes
Metal fluoride and oxides can store multiple lithium-ions through conversion
chemistry to enable high energy-density lithium-ion batteries. However, their
practical applications have been hindered by an unusually large voltage
hysteresis between charge and discharge voltage-profiles and the consequent low
energy efficiency (< 80%). The physical origins of such hysteresis are rarely
studied and poorly understood. Here we employ in situ X-ray absorption
spectroscopy (XAS), transmission electron microscopy (TEM),
density-functional-theory (DFT) calculations, and galvanostatic intermittent
titration technique (GITT) to first correlate the voltage profile of iron
fluoride (), a representative conversion electrode material, with
evolution and spatial distribution of intermediate phases in the electrode. The
results reveal that, contrary to conventional belief, the phase evolution in
the electrode is symmetrical during discharge and charge. However, the spatial
evolution of the electrochemically active phases, which is controlled by
reaction kinetics, is different. We further propose that the voltage hysteresis
in the electrode is kinetic in nature. It is the result of Ohmic
voltage drop, reaction overpotential, and different spatial distributions of
electrochemically-active phases (i.e. compositional inhomogeneity). Therefore,
the large hysteresis can be expected to be mitigated by rational design and
optimization of material microstructure and electrode architecture to improve
the energy efficiency of lithium-ion batteries based on conversion chemistry
A Novel Discipline in Embryology — Animal Embryo Breeding
The modern animal biotechnologies, such as animal cloning, transgenesis, sex determination, stem cells, designing new livestock, must be performed on animal gametes including sperm and oocytes, and embryos based on embryology theory. Currently, some key biotechnologies in embryology have become the most powerful tool for animal scientists and breeders to improve genetic construction of animal herds. Here, authors put forward a new concept of Animal Embryo Breeding Science to describe this discipline formation, development, and application in animal genetic improvement and breeding. The relationship of embryo breeding with other disciplines has been profiled. Thus, animal scientists and breeders can easily understand and apply embryo breeding theory and related key techniques to accelerate animal improvement speed, to modify genetic construction of animal population, and to design and create new animal individual or breed
Identification of SNPs in chemerin gene and association with carcass and meat quality traits of Qinchuan Cattle
Chemerin is a novel adipokine that regulates adipogenesis and adipocyte metabolism via its own receptor. In this study, two novel SNPs (868A>G in exon 2 and 2692C>T in exon 5) of chemerin gene were identified by PCR-SSCP and DNA sequencing technology. The allele frequencies of the novel SNPs were determined in the genetically diverse bovine breeds including six Chinese indigenous cattle breeds (Caoyuan red, Jiaxian red, Luxi, Nanyang, Qinchuan and Xia’nan cattle). We evaluated the potential association of the SNPs with traits measured by ultrasound measurement in 214 Qinchuan individuals. Furthermore, meat quality traits data gotten from carcass measurement in another 69 Qinchuan individuals were analyzed by the comparison between the genotypes and their phenotypic data. Results showed that SNP 868A>G had a significant association with the ultrasound loin-muscle area (P < 0.05), loin-eye area and water holding capability (P < 0.05). And also revealed significant effects of genotype on the ultrasound backfat thickness (P < 0.05), backfat thickness and water holding capability (P < 0.05) of SNP 2692C>T. It was shown that associations do exist between chemerin gene and carcass and meat quality traits. As a result of the small sample size of this study, it is proposed that further effort is required to validate these findings in larger populations. It could be concluded that ultrasound measurements are similar in accuracy to carcass measurements for predicting carcass and meat quality traits in cattle, and could be a useful predictor of retail yield in live animals.Keywords: Bos bovine, chemerin gene, PCR-SSCP, SNP, meat quality trait
Design Principles for Self-forming Interfaces Enabling Stable Lithium Metal Anodes
The path toward Li-ion batteries with higher energy-densities will likely
involve use of thin lithium metal (Li) anode (<50 m in thickness), whose
cyclability today remains limited by dendrite formation and low Coulombic
efficiency. Previous studies have shown that the solid-electrolyte-interface
(SEI) of Li metal plays a crucial role in Li electrodeposition and stripping.
However, design rules for optimal SEIs on lithium metal are not
well-established. Here, using integrated experimental and modeling studies on a
series of structurally-similar SEI-modifying compounds as model systems, we
reveal the relationship between SEI compositions, Li deposition morphology and
coulombic efficiency, and identify two key descriptors (ionicity and
compactness) for high performance SEIs through integrated experimental and
modeling studies. Using this understanding, we design a highly ionic and
compact SEI that shows excellent cycling performance in LiCoO-Li full cells
at practical current densities. Our results provide guidance for the rational
selection and optimization of SEI modifiers to further improve Li metal anodes.Comment: 21 pages, 6 figures and Supplementary Informatio
OLFML3 Expression is Decreased during Prenatal Muscle Development and Regulated by MicroRNA-155 in Pigs
The Olfactomedin-like 3 (OLFML3) gene has matrix-related function involved in embryonic development. MicroRNA-155 (miR-155), 21- to 23-nucleotides (nt) noncoding RNA, regulated myogenesis by target mRNA. Our LongSAGE analysis suggested that OLFML3 gene was differently expressed during muscle development in pig. In this study, we cloned the porcine OLFML3 gene and detected its tissues distribution in adult Tongcheng pigs and dynamical expression in developmental skeletal muscle (12 prenatal and 10 postnatal stages) from Landrace (lean-type) and Tongcheng (obese-type) pigs. Subsequently, we analyzed the interaction between OLFML3 and miR-155. The OLFML3 was abundantly expressed in liver and pancreas, moderately in lung, small intestine and placenta, and weakly in other tissues and postnatal muscle. There were different dynamical expression patterns between Landrace and Tongcheng pigs during prenatal skeletal muscle development. The OLFML3 was down-regulated (33-50 days post coitus, dpc), subsequently up-regulated (50-70 dpc), and then down-regulated (70-100 dpc) in Landrace pigs, while in Tongcheng pigs, it was down-regulated (33-50 dpc), subsequently up-regulated (50-55 dpc) and then down-regulated (55-100 dpc). There was higher expression in Tongcheng than Landrace in prenatal muscle from 33 to 60 dpc, and opposite situation from 65 to 100 dpc. Dual luciferase assay and real time PCR documented that OLFML3 expression was regulated by miR-155 at mRNA level. Our research indicated that OLFML3 gene may affect prenatal skeletal muscle development and was regulated by miR-155. These finding will help understanding biological function and expression regulation of OLFML3 gene in mammal animals
Streaming visualisation of quantitative mass spectrometry data based on a novel raw signal decomposition method
As data rates rise, there is a danger that informatics for high-throughput LC-MS becomes more opaque and inaccessible to practitioners. It is therefore critical that efficient visualisation tools are available to facilitate quality control, verification, validation, interpretation, and sharing of raw MS data and the results of MS analyses. Currently, MS data is stored as contiguous spectra. Recall of individual spectra is quick but panoramas, zooming and panning across whole datasets necessitates processing/memory overheads impractical for interactive use. Moreover, visualisation is challenging if significant quantification data is missing due to data-dependent acquisition of MS/MS spectra. In order to tackle these issues, we leverage our seaMass technique for novel signal decomposition. LC-MS data is modelled as a 2D surface through selection of a sparse set of weighted B-spline basis functions from an over-complete dictionary. By ordering and spatially partitioning the weights with an R-tree data model, efficient streaming visualisations are achieved. In this paper, we describe the core MS1 visualisation engine and overlay of MS/MS annotations. This enables the mass spectrometrist to quickly inspect whole runs for ionisation/chromatographic issues, MS/MS precursors for coverage problems, or putative biomarkers for interferences, for example. The open-source software is available from http://seamass.net/viz/
Estimation of genetic parameters for fertility traits in Chinese Holstein of south China
Introduction: Chinese Holstein in South China suffer heat stress for a long period, which leads to evolutionary differences from Chinese Holstein in North China. The aim of this study was to estimate the genetic parameters of fertility traits for Chinese Holstein in South China.Methods: A total of 167,840 Chinese Holstein heifers and cows from Guangming Animal Husbandry Co., LTD farms were used in this study. The fertility traits analyzed were calving interval (CI), days open (DO), age of first service (AFS), age of first calving (AFC), calving to first insemination (CTFS), first insemination to conception (FSTC), gestation length (GL), non-return rate to 56Â days (NRR), and number of services (NS).Results: The descriptive statistics revealed that the same trait in heifers performed better than in cows, which was consistent with the other studies. The heritabilities of fertility traits in this study ranged from close to 0 (for NS of cows) to 0.2474 (for AFC of heifers). The genetic correlation of NRR between heifers and cows was 0.9993, which indicates that the NRR for heifers and cows could be treated as one trait in this population.Conclusion: The heritabilities of fertility traits in Chinese Holstein in south China were quite different from the heritabilities of fertility traits in North China. NRR56, NS, AFC, and CI were suggested to be included into the selection index to improve fertility performance of Chinsese Holstein of south China. The results of this study could provide genetic parameters for the animal breeding program of Chinese Holstein in the south of China
Electrical Tuning of Neutral and Charged Excitons with 1-nm Gate
Electrical control of individual spins and photons in solids is key for
quantum technologies, but scaling down to small, static systems remains
challenging. Here, we demonstrate nanoscale electrical tuning of neutral and
charged excitons in monolayer WSe2 using 1-nm carbon nanotube gates.
Electrostatic simulations reveal a confinement radius below 15 nm, reaching the
exciton Bohr radius limit for few-layer dielectric spacing. In situ
photoluminescence spectroscopy shows gate-controlled conversion between neutral
excitons, negatively charged trions, and biexcitons at 4 K. Important for
quantum information processing applications, our measurements indicate gating
of a local 2D electron gas in the WSe2 layer, coupled to photons via trion
transitions with binding energies exceeding 20 meV. The ability to
deterministically tune and address quantum emitters using nanoscale gates
provides a pathway towards large-scale quantum optoelectronic circuits and
spin-photon interfaces for quantum networking.Comment: 21 pages, 11 figure
- …