绵羊FecB突变对BMPR1B活性及BMP/SMAD通路的影响研究进展

BMPR1B是绵羊中被鉴定的第一个多羔主效基因,但该基因中FecB突变增加绵羊排卵数的分子机制尚未解析。近年来发现BMPR1B活性受小分子抑制蛋白FKBP1A调控,该蛋白充当了BMPR1B及BMP/SMAD通路活性控制开关的关键作用且FecB突变恰好位于FKBP1A与BMPR1B结合位点附近。本文首先总结了BMPR1B和FKBP1A的蛋白结构,阐明二者空间结合区域及FecB突变的位置,进而预测了FecB突变与二者结合强弱的关系,最终提出了FecB突变通过影响BMPR1B与FKBP1A结合强度改变BMP/SMAD通路活性的科学假设,为后续探明FecB突变影响绵羊排卵数的分子机制提供了新思路。

Combined Transmission Interference Spectrum of No Core Fiber and BP Neural Network for Concentration Sensing Research

To investigate wavelength response of the no core fiber（NCF）interference spectrum to concentration,a three-layer back propagation（BP）neural network model was established to optimize the concentration sensing data.In this method,the measured wavelength and the corresponding concentration were trained by a BP neural network,so that the accuracy of the measurement system was optimized.The wavelength was used as the training set and got into the input layer of the three layer BP network model which is used as the input value of the network,and the corresponding actual concentration value was used as the output value of the network,and the optimal network structure was trained.This paper discovers a preferable correlation between the predicted value and the actual value,where the former is approximately equal to the latter.The correlation coefficients of the measured and predicted values for a sucrose concentration were 1.000 89 and 1.003 94;similarly,correlations of0.999 51 and 1.018 8 for a glucose concentration were observed.The results demonstrate that the BP neural network can improve the prediction accuracy of the nonlinear relationship between the interference spectral data and the concentration in NCF sensing systems.

Isotope effect and Coriolis coupling effect forthe Li + H(D)Cl → LiCl + H(D) reaction

A time-dependent quantum wave packet method is used to investigate the dynamics of the Li + H(D)Cl reaction based on a new potential energy surface(J. Chem. Phys. 146 164305(2017)). The reaction probabilities of the Coriolis coupled(CC) and centrifugal sudden(CS) calculations, the integral cross sections, the reaction rate constants are obtained. The rate constants of the Li + HCl reaction are within the error bounds at low temperature. A comparison of the CC and CS results reveals that the Coriolis coupling plays an important role in the Li + H(D)Cl reaction. The CC cross sections are larger than the CS results within the entire energy range, demonstrating that the Coriolis coupling effect can more effectively promote the Li + DCl reaction than the Li + HCl reaction. It is found that the isotope effect has a great influence on the title reaction.

Dynamic changes of genomic methylation profiles at different growth stages in Chinese Tan sheep

Background:Tan sheep,an important local sheep breed in China,is famous for their fur quality.One-month-old Tan sheep have white,curly hair with beautiful flower spikes,commonly known as“nine bends”,which has high economic value.However,the“nine bends”characteristic gradually disappears with age;consequently,the economic value of the Tan sheep decreases.Age-related changes in DNA methylation have been reported and may be responsible for age-induced changes in gene expression.Until now,no genome-wide surveys have been conducted to identify potential DNA methylation sites involved in different sheep growth stages.In this study we investigated the dynamic changes of genome-wide DNA methylation profiles in Tan sheep using DNA from skin and deep whole-genome bisulfite sequencing,and compared the DNA methylation levels at three different growth stages:1,24,and 48 months old(mon1,mon24,and mon48,respectively).Results:In this study,11 skin samples from three growth stages(four for mon1,four for mon24,and three for mon48)were used for DNA methylation analysis and gene expression profiling.There were 52,288 and 236 differentially methylated genes(DMGs)identified between mon1 and mon24,mon1 and mon48,and mon24 and mon48,respectively.Of the differentially methylated regions,1.11%,7.61%,and 7.65% were in the promoter in mon1 vs.mon24,mon24 vs.mon48,and mon1 vs.mon48,respectively.DMGs were enriched in the MAPK and WNT signaling pathways,which are related to age growth and hair follicle morphogenesis processes.There were 51 DMGs associated with age growth and curly fleece formation.Four DMGs between mon1 and mon48(KRT71,CD44,ROR2 and ZDHHC13)were further validated by bisulfite sequencing.Conclusions:This study revealed dynamic changes in the genomic methylation profiles of mon1,mon24,and mon48 sheep,and the percentages of methylated cytosines were 3.38%,2.85% and 4.17%,respectively.Of the DMGs,KRT71 and CD44 were highly methylated in mon1,and ROR2 and ZDHHC13 were highly methylated in mon48.These findings provide foundational information that may be used to develop strategies for potentially retaining the lamb fur and thus improving the economic value of Tan sheep.

Cationized Melamine-formaldehyde Resin for Improving the Wet Strength of Paper

In this work, melamine-formaldehyde resin was cationized by adding modifiers so that the fibers closely bonded to improve their usability and the wet strength of paper was greatly improved. Triethanolamine and dimethylamine were added to modify the melamine-formaldehyde resin,respectively.The mechanism of the cationized resin was explored and the possible chemical reactions were deduced. It was concluded that,with the use of triethanolamine,the most optimum product was obtained by hydroxymethylation for 30 min with a temperature of 85℃ and p H of 9. 0 where n( melamine) ∶ n( formaldehyde) ∶ n( methanol) ∶ n( triethanolamine) was 100 ∶ 330 ∶ 450 ∶ 15. With the combined use of dimethylamine and methanol,the optimal product was acquired by condensation for 30 min at a temperature of 50℃ and p H of 2. 0 at melamine, formaldehyde, methanol, and dimethylamine molar ratio of100∶ 330∶ 350∶ 20. With the only use of dimethylamine,the optimal product was obtained by condensation at melamine,formaldehyde,dimethylamine molar ratio of 100∶ 330∶ 10. The wet tensile strength of fruit-bagging paper was improved by adding cationized melamine-formaldehyde resin. The zeta potential,charge density,and conductivity of the melamine-formaldehyde resin were also studied.

MAPK4 facilitates angiogenesis by inhibiting the ERK pathway in non-small cell lung cancer

Background:Angiogenesis plays an important role in the occurrence and development of non-small cell lung cancer(NSCLC).The atypical mitogen-activated protein kinase 4(MAPK4)has been shown to be involved in the pathogenesis of various diseases.However,the potential role of MAPK4 in the tumor angiogenesis of NSCLC remains unclear.Methods:Adult male C57BL/6 wild-type mice were randomly divided into the control group and p-siMAPK4 intervention group,respectively.The cell proliferation was analyzed with flow cytometry and immunofluorescence staining.The vascular density in tumor mass was analyzed by immuno-fluorescence staining.The expressions of MAPK4 and related signaling molecules were detected by western blot analysis and immunofluorescence staining,and so on.Results:We found that the expression of MAPK4,which was dominantly expressed in local endothelial cells(ECs),was correlated with tumor angiogenesis of NSCLC.Furthermore,MAPK4 silencing inhibited the proliferation and migration abilities of human umbilical vein ECs(HUVECs).QKHZC-2020-4Y156,QKH-JC-2018-1428,QKH-RC-2019-5612;Collaborative Innovation Center of Chinese Ministry of Education,Grant/Award Number:2020-39;Program for Science and Technology Joint Fund Project in Zunyi Science and Technology Bureau and Zunyi Medical University,Grant/Award Numbers:ZSKH-RPT-2020-6,ZSKH-HZ-2021-193;Graduate Research Fund of Zunyi Medical University,Grant/Award Number:2023-ZYK-171 Global gene analysis showed that MAPK4 silencing altered the expression of multiple genes related to cell cycle and angiogenesis pathways,and that MAPK4 silencing increased transduction of the extracellular regulated protein kinases 1/2(ERK1/2)pathway but not Akt and c-Jun n-terminal kinase pathways.Further analysis showed that MAPK4 silencing inhibited the proliferation and migration abilities of HUVECs cultured in tumor cell supernatant,which was accompanied with increased transduction of the ERK1/2 pathway.Clinical data analysis suggested that the higher expression of MAPK4 and CD34 were associated with poor prognosis of patients with NSCLC.Targeted silencing of MAPK4 in ECs using small interfering RNA driven by the CD34 promoter effectively inhibited tumor angiogenesis and growth of NSCLC in vivo.Conclusion:Our results reveal that MAPK4 plays an important role in the angiogenesis and development of NSCLC.MAPK4 may thus represent a new target for NSCLC.

平衡三阳离子钙钛矿中带隙和电荷传输以实现高效的室内光伏

带隙可调的钙钛矿材料在室内光伏(IPVs)领域具有广阔的应用前景.然而,与室内光相匹配的宽带隙钙钛矿通常导电性较差,缺陷密度较高,往往不利于电荷提取和传输,限制了其光伏特性.在这里,我们通过调节Br/I比,探究了不同带隙三阳离子钙钛矿的IPVs特性.研究表明,宽带隙钙钛矿能充分利用室内光,在低照度下能获得较高的开路电压,但高Br/I比的钙钛矿具有较高的缺陷密度,不利于获得高短路电流密度和填充因子.通过进一步研究不同带隙钙钛矿的结晶动力学、缺陷密度和电荷传输特性,我们发现主流观念中高效IPVs着重考虑室内光伏材料的带隙是不全面的,我们证明了通过适当降低宽带隙晶体中的Br含量可以获得室内光伏特性更优异的器件.也就是说,室内光伏晶体材料的制备需要兼顾带隙和电荷传输特性.在此工作中,平衡带隙和电荷传输的器件(Br 0.23,1.62 eV)在1035 lux的LED灯照射下取得了40.71%的最佳效率.我们的研究为高效室内光伏的设计提供了新思路.

Tuning exciton dynamics by the dielectric confinement effect in quasi-two-dimensional perovskites

The dielectric confinement effect plays an essential role in optoelectronic devices.Existing studies on the relationship between the dielectric confinement and the photoelectric properties are inadequate.Herein,three organic spacers with different dielectric constants are employed to tune the exciton dynamics of quasi-two-dimensional(quasi-2D)Ruddlesden–Popper perovskite films.Femtosecond transient absorption spectroscopy reveals that the small dielectric constant ligand enables a weak dynamic disorder and a large modulation depth of the coherent phonons,resulting in a more complete energy transfer and the inhibition of a trap-mediated nonradiative recombination.Additionally,the increase in the bulk-ligand dielectric constant reduces the corresponding exciton binding energy and then suppresses the Auger recombination,which is beneficial for high-luminance lightemitting diodes.This work emphasizes the importance of dielectric confinement for regulating the exciton dynamics of layered perovskites.

Multiband metamaterial emitters for infrared and laser compatible stealth with thermal management based on dissipative dielectrics

The modulation of thermal radiation in the infrared region is a highly anticipated method to achieve infrared sensing and camouflage. Here, a multiband metamaterial emitter based on the Al∕SiO_(2)∕Al nanosandwich structure is proposed to provide new ideas for effective infrared and laser-compatible camouflage. By virtue of the intrinsic absorption and magnetic resonance property of lossy materials, the thermal radiation in the infrared region can be rationally modulated. The fabricated samples generally present low emissivity(ε_(3–5μm)= 0.21,ε_(8–14μm)= 0.19) in the atmospheric windows to evade infrared detection as well as high emissivity(ε_(5–8μm)= 0.43) in the undetected band for energy dissipation. Additionally, the laser camouflage is also realized by introducing a strong absorption at 10.6 μm through the nonlocalized plasmon resonance of the SiO_(2)layer.Moreover, the fabricated emitter shows promising prospects in thermal management due to the good radiative cooling property that is comparable to the metallic Al material. This work demonstrates a multiband emitter based on the metasurface structure with compatible infrared-laser camouflage as well as radiative cooling properties, which is expected to pave new routes for the design of thermal radiation devices.

Tuning coherent phonon dynamics in two-dimensional phenylethylammonium lead bromide perovskites

Organic-inorganic layered perovskites are two-dimensional quantum well layers in which the layers of lead halide octahedra are stacked between the organic cation layers.The packing geometry of the soft organic molecules and the stiff ionic crystals induce structural deformation of the inorganic octahedra,generating complex lattice dynamics.Especially,the dielectric confinement and ionic sublattice lead to strong coupling between the photogenerated excitons and the phonons from the polar lattice which intensively affects the properties for device applications.The anharmonicity and dynamic disorder from the organic cations participate in the relaxation dynamics coupled with excitations.However,a detailed understanding of this underlying mechanism remains obscure.This work investigates the electron–optical phonon coupling dynamics by employing ultrafast pump-probe transient absorption spectroscopy.The activated different optical phonon modes are observed via systematic studies of(PEA)_(2)PbBr_(4) perovskite films on the ultrafast lattice vibrational dynamics.The experimental results indicate that solvent engineering has a significant influence on lattice vibrational modes and coherent phonon dynamics.This work provides fresh insights into electron-optical phonon coupling for emergent optoelectronics development based on layered perovskites.

Enhanced nitrogen electroreduction performance by the reorganization of local coordination environment of supported single atom on N(O)-dual-doped graphene

Developing stable and efficient catalysts for the electroreduction of nitrogen remains a huge challenge and single atom catalysts(SACs)are expected to achieve relatively high ammonia selectivity at low applied potential.Based on density functional theory calculations,the potential application of 27 single transition metal(TM=Sc-Zn,Y-Ag,Hf-Au)atoms supported by N(O)-dualdoped graphene(TM-O_(2)N_(2)/G)for the electroreduction of nitrogen is intensively investigated.At low nitrogen coverage,W(Mo,Nb,Ta)-O_(2)N_(2)/G are predicted to yield low ammonia selectivity(<13%)at limiting-potential of-0.58,-0.53,-0.56,and-0.76 V starting from adsorbed nitrogen with side-on mode,respectively.With the increasing N_(2)coverage,the TM-O_(2)N_(2)/G is reconstructed as TM-(N_(2))2N_(2)/graphene.The electroreduction of nitrogen proceeds from end-on adsorbed nitrogen molecule with high ammonia selectivity,and the limiting-potentials are theoretically predicted as-0.20,-0.40,-0.29,and-0.21 V on W(Mo,Nb,Ta)-(N_(2))2N_(2)/G,respectively.It is suggested that utilizing the reorganization of local coordination environments of SACs by high coverage of reactant molecules under reaction condition can not only enhance the activity at lower limiting-potential but also improve the ammonia selectivity.

Symmetry-protected third-order exceptional points in staggered flatband rhombic lattices

Higher-order exceptional points(EPs), which appear as multifold degeneracies in the spectra of non-Hermitian systems, are garnering extensive attention in various multidisciplinary fields. However, constructing higher-order EPs still remains a challenge due to the strict requirement of the system symmetries. Here we demonstrate that higher-order EPs can be judiciously fabricated in parity–time(PT)-symmetric staggered rhombic lattices by introducing not only on-site gain/loss but also non-Hermitian couplings. Zero-energy flatbands persist and symmetry-protected third-order EPs(EP3s) arise in these systems owing to the non-Hermitian chiral/sublattice symmetry, but distinct phase transitions and propagation dynamics occur. Specifically, the EP3 arises at the Brillouin zone(BZ) boundary in the presence of on-site gain/loss. The single-site excitations display an exponential power increase in the PT-broken phase. Meanwhile, a nearly flatband sustains when a small lattice perturbation is applied. For the lattices with non-Hermitian couplings, however, the EP3 appears at the BZ center. Quite remarkably, our analysis unveils a dynamical delocalization-localization transition for the excitation of the dispersive bands and a quartic power increase beyond the EP3. Our scheme provides a new platform toward the investigation of the higher-order EPs and can be further extended to the study of topological phase transitions or nonlinear processes associated with higher-order EPs.

All-metallic metasurfaces towards high-performance magneto-plasmonic sensing devices

Magneto-plasmonic sensors based on surface plasmon resonance have been studied considerably in recent years,as they feature high sensitivity and ultrahigh resolution.However,the majority of such investigations focus on prism-based sandwich architectures that not only impede the miniaturization of devices but also have a weak transverse magneto-optical Kerr effect(TMOKE)in magnitude.Herein,we theoretically demonstrate a magneto-plasmonic sensor composed of Au/Co bilayer nanodisk arrays on top of optically thick metallic films,which supports a narrow surface plasmon resonance(SPR)with a bandwidth of 7 nm and allows for refractive index sensitivities as high as 717 nm/RIU.Thanks to the high-quality SPR mode,a Fano-like TMOKE spectrum with a subnanometer bandwidth can be achieved in the proposed structure,thereby giving rise to ultrahigh sensing of merit values as large as 7000 in water.Moreover,we demonstrate a large TMOKE magnitude that exceeds 0.6.The value is 1 order of magnitude larger than that of magneto-plasmonic sensors reported.We also demonstrate that the behavior of TMOKE spectra can be controlled by tuning the geometrical parameters of the device including the diameter and thickness of nanodisk arrays.This work provides a promising route for designing magneto-plasmonic sensors based on metasurfaces or metamaterials.

Ultra-high current gain tunneling hot-electron transfer amplifier based on vertical van der Waals heterojunctions

Due to the backscattered parasitic current from the barriers,the current gain of the widely used amplifier is far from ideal.In this work,we demonstrate a vertical Au/Al2O3/BP/MoS2 tunneling hot-electron transfer amplifier with a hot-electron emitter-base junction and a p-n junction as the base-collector barrier.Fairly monoenergetic electrons traverse through the ultrathin Al2O3 dielectric via tunneling,which are accelerated and shifted to the collector region.The devices exhibit a high current on-off ratio of>105 and a high current density(JC)of∼1,000 A/cm2 at the same time.Notably,this work demonstrates a common-emitter current gain(β)value of 1,384 with a nanowatt power consumption at room temperature,which is a record high value among the all 2D based hot-electron transistors.Furthermore,the temperature dependent performance is investigated,and theβvalue of 1,613 is obtained at 150 K.Therefore,this work presents the potential of 2D based transistors for high-performance applications.

Health Status of Left-Behind Children and Parenting Behaviors of Caregivers in Poor Rural Areas-6 Provinces,China,2018

What is already known about this topic?China has a significant population of left-behind children,and their health and living environments remain a major public health challenge.Children under 6 years old are especially vulnerable to poor health knowledge and behaviors of their caregivers.What is added by this report?The prevalence of stunting,being underweight,and often sick were 13%,3.4%,and 5%,respectively.Only 53.9%of left-behind children could eat meat often,and 59.5%could control their intake of sugary drinks.The proportions of children who had a safe home environment,a safe play environment,and no family violence were 22.5%,75.3%,and 45.9%,respectively.The percentages of caregivers who ensured that they rarely left their children alone and were always in their sight are 76.1%and 92.4%,respectively.What are the implications for public health practice?The implementation of early home visits is necessary to improve the physical health and safety of the living environment of left-behind children.Primary health workers should pay attention to improving the health knowledge and behaviors of caregivers.

Carbon-doping-induced negative differential resistance in armchair phosphorene nanoribbons

By using a combined method of density functional theory and non-equilibrium Green＇s function formalism,we investigate the electronic transport properties of carbon-doped armchair phosphorene nanoribbons（APNRs）.The results show that C atom doping can strongly affect the electronic transport properties of the APNR and change it from semiconductor to metal.Meanwhile,obvious negative differential resistance（NDR） behaviors are obtained by tuning the doping position and concentration.In particular,with reducing doping concentration,NDR peak position can enter into m V bias range.These results provide a theoretical support to design the related nanodevice by tuning the doping position and concentration in the APNRs.