空位有序双钙钛矿A2BX6的弹性和热电性质的第一性原理研究

卤化物钙钛矿在热电应用中表现出了巨大的潜力。准确了解卤化物钙钛矿的热电传输性质对于进一步提高热电设备的应用效率至关重要。本研究采用了Perdew-Burke-Ernzerhof(PBE)和修正的Becke Johnson(mBJ)交换关联泛函探究了卤化物双钙钛矿Rb_(2)SnI6、Rb_(2)PdI6和Cs_(2)PtI6的弹性和热电性质。通过对这些材料的力学稳定性、有效质量、塞贝克系数、功率因子和热电品质因数的研究,我们发现,这三种化合物都是力学稳定的,并且具有可塑性。这些化合物是窄带隙半导体,具有简并的带边结构,结合低的载流子有效质量使得它们具有热电应用潜力。Cs_(2)PtI6在空穴掺杂在500 K温度下可以达到0.76 mV·K^(−1)的高塞贝克系数。由于高塞贝克系数和最大功率因子,Rb_(2)SnI6、Rb_(2)PdI6和Cs_(2)PtI6在p型掺杂下具有高的热电品质因数,分别为0.91、0.96和0.98。总体而言,我们的研究为卤化物钙钛矿的热电性能提供了新的见解,为这些化合物的实验合成提供了有价值的参考。

The protective roles of tea tree oil extracts in bovine mammary epithelial cells and polymorphonuclear leukocytes

Background: Tea tree oil(TTO) plays an important role in antibacterial activity and alleviating the inflammatory responses. Bovine mammary epithelium and polymorphonuclear leukocytes(PMNL) can actively respond to bovine mastitis infection. However, regulatory effects of TTO extracts on the innate immune response of bovine mammary epithelial cells(BMECs) and PMNL remain not reported. Therefore, aim of the study was to evaluate the effects of TTO extracts on the m RNA levels of the genes involved in the innate immune response of BMECs and PMNL.Results: Our results demonstrated that addition of 0.025% and 0.05% TTO increased the proliferation of BMECs, and significantly enhanced(P < 0.05) the viability of BMECs exposed to Staphylococcus aureus(S. aureus). An inhibitory effect was observed against the growth of S. aureus by TTO incubation. The 0.05% TTO reduced S. aureus biofilm formation, association and invasion of S. aureus to BMECs, and changed the morphological and structural features of S. aureus. The proinflammatory cytokines IL-1β, IL-6, and TNF-α were decreased(P < 0.001) by the incubation of TTO. Interestingly, the expression of IL-8 known for PMNL chemotactic function was elevated(P < 0.05) by 0.05%TTO treatment. Consistently, 0.05% TTO increased the migration of PMNL in S. aureus-exposed BMECs when compared with S. aureus treatment alone(P < 0.05). In addition, PMNL incubated with 0.05% TTO decreased the levels of NFKB inhibitor alpha(NFKBIA) and TNF-α.Conclusions: Our results indicate that use of TTO can relieve the BMECs pro-inflammatory response caused by S.aureus and promote the migration of PMNL to mount the innate immune responses, and it may be novel strategy for the treatment of bovine mastitis caused by S. aureus.

Al elopathic Effects of Melilotus officinalis Desr. against Weeds

In this study, the allelopathic effects of 100 g/L water extract of Melilotus offtcinalis Desr. on seed germination and seedling growth of Melilotus offwinalis Desr., Trifolium pretense L. , Medicago sativa L. cv. Victoria, Echinochloa crusgalli （ L. ） Beauv., Lxer/s chinensis （ Thunb. ） Nakai and Plantago asiatica L. were investigated by biological assay. Dried powder of Melilotus officinalis Desr. was applied to the field in spring and winter to verify the inhibitory effects of Me- lilotus officinalis Desr. on weed biomass in the experimental field and compare the effects between Melilotus offwinalis Desr. and a variety of commonly used chemi- cal herbicides on weed suppression. The results showed that water extract of Melilotm officinalis Desr. posed significant effects on seed germination and seedling growth of Trifolium pretense L. , Echinochloa crusgalli （ L. ） Beauv. , Lxeris chinensis （ Thunb. ） Nakm, Plantago asiatica L. , Melilotus o^tcinalis Desr. and Medi- cago sativa L. cv. Victoria, exhibiting strong allelopathic effects, but the inhibition rate varied greatly among different plant species. Therefore, the allelopathic effects of Melilotus o^winalis Desr. should be utilized appropriately in practical applieatians. Dried powder of Melilotus officinalis Desr. significantly reduced weed quantity in the field for a short duration, which should be administered multiple times in a sufficient amount for weed control in the production.

High-throughput computational material screening of the cycloalkane-based two-dimensional Dion–Jacobson halide perovskites for optoelectronics

Two-dimensional(2D) layered perovskites have emerged as potential alternates to traditional three-dimensional(3D)analogs to solve the stability issue of perovskite solar cells. In recent years, many efforts have been spent on manipulating the interlayer organic spacing cation to improve the photovoltaic properties of Dion–Jacobson(DJ) perovskites. In this work, a serious of cycloalkane(CA) molecules were selected as the organic spacing cation in 2D DJ perovskites, which can widely manipulate the optoelectronic properties of the DJ perovskites. The underlying relationship between the CA interlayer molecules and the crystal structures, thermodynamic stabilities, and electronic properties of 58 DJ perovskites has been investigated by using automatic high-throughput workflow cooperated with density-functional(DFT) calculations.We found that these CA-based DJ perovskites are all thermodynamic stable. The sizes of the cycloalkane molecules can influence the degree of inorganic framework distortion and further tune the bandgaps with a wide range of 0.9–2.1 eV.These findings indicate the cycloalkane molecules are suitable as spacing cation in 2D DJ perovskites and provide a useful guidance in designing novel 2D DJ perovskites for optoelectronic applications.

Butyrate inhibits the bovine rumen epithelial cell proliferation via downregulation of positive regulators at G0/G1 phase checkpoint

Short-chain fatty acids(SCFAs)butyrate promote the postnatal rumen epithelial development and maturation in ruminants.However,molecular mechanisms of effects of butyrate on the bovine rumen epithelial cells(BRECs)proliferation remain elusive.Therefore,purpose of this study was to investigate the effects of butyrate on the expression of genes and proteins at G0/G1 and S phase of BRECs cycle.Our results showed that BRECs treated with butyrate inhibited(P<0.05)the proliferation of BRECs,relatively to control.Flow cytometric assays revealed that butyrate triggers the BRECs cycle arrest at the G0/G1 phase.qRT-PCR analyses of mRNA level of genes involved in the G0/G1 phase of cell cycle showed that butyrate significantly upregulated(P<0.001)the expression of mRNA encoding p21^(Cip1)compared with control group,but it decreased(P<0.05)the mRNA levels of cyclin D1 and CDK4 genes at G0/G1 phase checkpoint compared with control.Moreover,Western blot also revealed that butyrate downregulated the expression of cyclin D3,CDK6,p-Rb,and E2F1 proteins involved in the modulation of G0/G1 phase of cell cycle.In conclusion,our results demonstrated that butyrate inhibits the proliferation of BRECs via downregulation of positive regulators at G0/G1 phase checkpoint.

Hexokinase 1 and 2 mediates glucose utilization to regulate the synthesis of kappa casein via ribosome protein subunit 6 kinase 1 in bovine mammary epithelial cells

Glucose plays a vital part in milk protein synthesis through the mTOR signaling pathway in bovine mammary epithelial cells(BMEC).The objectives of this study were to determine how glucose affects hexokinase(HK)activity in BMEC and investigate the regulatory effect of HK in kappa casein(CSN3)synthesis via the mechanistic target of rapamycin complex 1(mTORC1)signaling pathway in BMEC.For this,HK1 and HK2 were knocked out in BMEC using the CRISPR/Cas9 system.The gene and protein expression,glucose uptake,and cell proliferation were measured.We found that glucose uptake,cell proliferation,CSN3 gene expression levels,and expression of HK1 and HK2 increased with increasing glucose concentrations.Notably,glucose uptake was significantly reduced in HK2 knockout(HK2KO)BMEC treated with 17.5 mM glucose.Moreover,under the same glucose treatment conditions,the proliferative ability and abundance of CSN3 were significantly diminished in both HK1 knockout(HK1KO)and HK2KO BMEC compared with that in wild-type BEMC.We further observed that the phosphorylation levels of ribosome protein subunit 6 kinase 1(S6K1)were reduced in HK1KO and HK2KO BMEC following treatment with 17.5 mM glucose.As expected,the levels of glucose-6-phosphate and the m RNA expression levels of glycolysis-related genes were decreased in both HK1KO and HK2KO BMEC following glucose treatment.These results indicated that the knockout of HK1 and HK2 inhibited cell proliferation and CSN3 expression in BMEC under glucose treatment,which may be associated with the inactivation of the S6K1 and inhibition of glycolysis.

Alloy-induced reduction and anisotropy change of lattice thermal conductivity in Ruddlesden–Popper phase halide perovskites

The effective modulation of the thermal conductivity of halide perovskites is of great importance in optimizing their optoelectronic device performance.Based on first-principles lattice dynamics calculations,we found that alloying at the B and X sites can significantly modulate the thermal transport properties of 2D Ruddlesden−Popper(RP)phase halide perovskites,achieving a range of lattice thermal conductivity values from the lowest(κ_(c)=0.05 W·m^(−1)·K^(−1)@Cs_(4)AgBiI_(8))to the highest(κ_(a/b)=0.95 W·m^(−1)·K^(−1)@Cs4NaBiCl_(4)I_(4)).Compared with the pure RP-phase halide perovskites and three-dimensional halide perovskite alloys,the two-dimensional halide perovskite introduces more phonon branches through alloying,resulting in stronger phonon branch coupling,which effectively scatters phonons and reduces thermal conductivity.Alloying can also dramatically regulate the thermal transport anisotropy of RP-phase halide perovskites,with the anisotropy ratio ranging from 1.22 to 4.13.Subsequently,analysis of the phonon transport modes in these structures revealed that the lower phonon velocity and shorter phonon lifetime were the main reasons for their low thermal conductivity.This work further reduces the lattice thermal conductivity of 2D pure RP-phase halide perovskites by alloying methods and provides a strong support for theoretical guidance by gaining insight into the interesting phonon transport phenomena in these compounds.

Potential and challenges of tannins as an alternative to in-feed antibiotics for farm animal production

Naturally occurring plant compounds including tannins, saponins and essential oils are extensively assessed as natural alternatives to in-feed antibiotics.Tannins are a group of polyphenolic compounds that are widely present in plant region and possess various biological activities including antimicrobial,anti-parasitic, anti-viral, antioxidant, anti-inflammatory, immunomodulation, etc.Therefore, tannins are the major research subject in developing natural alternative to in-feed antibiotics.Strong protein affinity is the well-recognized property of plant tannins, which has successfully been applied to ruminant nutrition to decrease protein degradation in the rumen, and thereby improve protein utilization and animal production efficiency.Incorporations of tannin-containing forage in ruminant diets to control animal pasture bloat, intestinal parasite and pathogenic bacteria load are another 3 important applications of tannins in ruminant animals.Tannins have traditionally been regarded as "anti-nutritional factor" for monogastric animals and poultry, but recent researches have revealed some of them, when applied in appropriate manner, improved intestinal microbial ecosystem, enhanced gut health and hence increased productive performance.The applicability of plant tannins as an alternative to in-feed antibiotics depends on many factors that contribute to the great variability in their observed efficacies.

Effects of dietary alfalfa flavonoids extraction on growth performance,organ development and blood biochemical indexes of Yangzhou geese aged from 28 to 70 days

This experiment was conducted to study the effects of dietary alfalfa flavonoids extraction supplemental level on growth performance, organ development and blood biochemical indexes of Yangzhou geese at the age of 28 to 70 days. Two hundred and forty 21-day-old healthy male geese with similar body weight were randomly distributed into 4 groups with 6 replicates per group and 10 geese per replicate. Geese in the control group were fed a basal diet and the others in the experimental groups(groups 1,2, and 3) were fed experimental diets supplemented with 150, 300 and 450 mg/kg alfalfa flavonoids extraction(the concentration of it was 81%), respectively. The experiment had 7 days for pre-test and 42 days for formal test.The results showed that the final body weight and average daily intake of group 2 were significantly higher than those of other groups(P < 0.05). The average daily gain of group 2 was significantly higher than that in the control group and group 1(P < 0.05). There was no significant difference in feed-to-gain ratio between each group(P > 0.05). Pre-slaughter live weight, carcass weight, slaughter rate, semieviscerated weight, semi-eviscerated rate, eviscerated weight, eviscerated rate, leg muscle weight and leg muscle rate had no significant difference between each group(P > 0.05). The breast muscle weight and ratio of each test group were significantly higher than those in the control group(P < 0.05) and the group2 was the best. The abdominal fat weight and ratio in the group 1 were significantly higher than those in the control group and group 3(P < 0.05) and the tibia weight in the group 2 was significantly higher than that in the control group and group 1(P < 0.05); There were no significant differences in heart weight,liver weight and the gland stomach weight among all groups(P > 0.05). Spleen weight in test groups was significantly higher than that in the control group(P < 0.05). The bursa weight and muscular stomach weight in the group 2 were significantly higher than those in the control group and group 1(P < 0.05). In serum, total cholesterol, triglycerides, low-density lipoprotein and urea nitrogen in the group 2 were significantly lower comparing with those in the control group(P < 0.05). High-density lipoprotein in the group 2 was significantly higher than that in other groups(P < 0.05). There were no significant differences in total serum protein, albumin, globulin and albumin/globulin among all groups(P > 0.05). Alanine aminotransferase and aspartate transaminase(AST) in groups 2 and 3 were higher than those in the group1 and control group but not obvious(P > 0.05) and alkaline phosphatase(ALP) in groups 1 and 2 was higher than that in the control group and group 3(P > 0.05). It is concluded that alfalfa flavonoids extraction added in dietary feed improve the growth performance, organ development and blood biochemical indexes of Yangzhou geese. It is concluded that 300 mg/kg supplemental level of the dietary alfalfa flavonoids extraction is optimal in this experiment.

Effects of bamboo vinegar powder on growth performance and mRNA expression levels of interleukin-10,interleukin-22,and interleukin-25 in immune organs of weaned piglets

The aim of this study was to explore the effects of bamboo vinegar powder on growth performance,diarrhea situation and mRNA expression levels of cytokines i.e., interleukin-10(IL-10), interleukin-22(IL-22), and interleukin-25(IL-25) in immune organs of weaned piglets, and to accumulate theoretical data for the application of bamboo vinegar powder in weaned piglet production. Forty-five crossbred(Duroc × Landrace × Yorkshire, all male) weaned piglets with similar body weight(6.74 ± 0.17 kg) at 31 days of age were randomly assigned to 5 treatments with 3 replicates per treatment and 3 piglets in each replicate. The five treatments were as follows: CON(a basal diet), ANT(the basal diet + 0.12% antibiotics),BV1(the basal diet + 0.1% bamboo vinegar powder), BV5(the basal diet + 0.5% bamboo vinegar powder),BV10(the basal diet + 1.0% bamboo vinegar powder). This experiment lasted 35 days. The growth performance and diarrhea situation were recorded. The relative mRNA expression levels of IL-10, IL-22 and IL-25 in liver, spleen, duodenum and mesenteric lymph nodes were detected by real-time PCR. Feed:gain of BV5 was significantly lower than that of CON(P < 0.05). In comparison with CON, diarrhea rate and diarrhea index of BV1 and BV5 all tended to decrease(P < 0.1). Compared with CON, mRNA expression level of IL-10 in liver of ANT tended to be lower(P < 0.1) and these of BV1, BV5 and BV10 were significantly reduced(P < 0.05). The mRNA expression levels of IL-10 in duodenum of ANT, BV1, BV5 and BV10 were all lower than those of CON, of which BV10 had significantly decreased IL-10 mRNA expression in duodenum(P < 0.05). The mRNA expression levels of IL-22 in duodenum of ANT, BV1, BV5 and BV10 all tended to be inhibited compared with CON(P < 0.1). With the increase of bamboo vinegar powder dosage, mRNA expression levels of IL-25 in spleen and mesenteric lymph nodes of BV1, BV5 and BV10 tended to be up-regulated. Overall, bamboo vinegar powder could improve growth performance,and regulate mRNA expression levels of IL-10, IL-22 and IL-25 in immune organs of weaned piglets. The dosage at 0.5% showed optimum effects.

Differential Responses Between Monocytes and Monocyte-Derived Macrophages for Lipopolysaccharide Stimulation of Calves

In this experiment Toll-like receptor expression pattern in monocytes and monocyte-derived macrophages by lipopolysaccharide （LPS） stimulation was examined. Jugular venous blood was collected from four Japanese calves, and the peripheral blood mononuclear cells （PBMCs） were isolated. The cells were directly used for collecting monocytes by magnetic cell sorting or cultured for 7 days to collect monocyte-derived macrophages in Repcell. Then we analyzed the mRNA expression pattern of TLRs and cytokines in monocytes and monocyte-derived macrophages after LPS stimulation for 24 h. LPS stimulation of both monocytes and monocyte-derived macrophages resulted in an increase in the levels of mRNA transcripts for TNF-α IL-6 and IL-8. Moreover, TNF-α and IL-6 mRNA expressions were significantly augmented by LPS stimulation in monocyte-derived macrophages. TLRs mRNA expressions were unchanged after LPS stimulation of monocytes, while TLRs mRNA expressions in monocyte-derived macrophages were complicated. TLR1, 3, 5, 8 and 10 were significantly decreased after LPS stimulation and there were no differences in the mRNA expressions of TLR2, 4, 6 and 7 between the groups of control and LPS stimulation. Besides, no expression of TLR9 was found. As antigen presenting cells, monocytes and monocyte-derived macrophages respond differently to LPS, so they may have different functions in the innate immune system.