Effect of Extending Voluntary Waiting Period on Health of Holstein Friesian Dairy Cows

The aim of this of this experimental study to investigate the effect of 3 voluntary waiting periods (VWP) on health of dairy cows. A total of 100 lactations of 100 Holstein Friesian cows with high milk production (average 9.442 ± 620 kg) were randomly (based on the ear tags digits of cows) distributed to 1 to 3 experimental groups with VWP of 50 (VWPG50;n = 32), 100 (VWPG100;n = 34) or 150 days (VWPG150;n = 34). Observations relating to diseases of the cows were made by the farm veterinarian and research personnel. Were defined eight disease: puerperal fever, retained fetal membranes, displaced abomasum, metritis, clinical ketosis, clinical mastitis, ovarian cysts, and claw diseases. The experimental days (ED) were from 4 days in milk (DIM) to 100 days after the next calving. The experiment was managed at Dairy Research Farm ?imnic-Craiova January 2018 to December 2022. A clear set of clinical signs were used to define a case at the diseases without the need for laboratory confirmation. Values of Lactational incidence risk (LIR) median postpartum days at diagnosis and pairwise comparison of proportion between VWPs were calculated. LIR for puerperal fiver, retained fetal membranes, displaced abomasum, clinical ketosis, clinical mastitis, ovarian cysts and claw disease were 4;5;2;8;8;and 4% respectively. Numerically, cows with VWP of 100 and150 days had more disease cases compared with VWP of 50 days. The differences between experimental groups of cows regarding proportions of cows with disease cases were not statistically significant. Any of the eight disorders reported in this study was analyzed independently to other health problems. For all enrolled cows (n = 100) VWP was extended until 100 or 150 days postpartum with no effect on the lactational incidence risk for the eight disorders analyzed.

Repeated inoculation with rumen fluid accelerates the rumen bacterial transition with no benefit on production performance in postpartum Holstein dairy cows

Background The dairy cow’s postpartum period is characterized by dramatic physiological changes,therefore imposing severe challenges on the animal for maintaining health and milk output.The dynamics of the ruminal microbiota are also tremendous and may play a crucial role in lactation launch.We aim to investigate the potential benefits of early microbial intervention by fresh rumen microbiota transplantation(RMT)and sterile RMT in postpartum dairy cows.Twelve fistulated peak-lactation dairy cows were selected to be the donors for rumen fluid collection.Thirty postpartum cows were divided into 3 groups as the transplantation receptors respectively receiving 10 L fresh rumen fluid(FR),10 L sterile rumen fluid(SR),or 10 L saline(CON)during 3 d after calving.Results Production performance,plasma indices,plasma lipidome,ruminal microbiome,and liver transcriptome were recorded.After fresh and sterile RMT,we found that the molar proportion of propionic acid was increased on d 7 in the FR and SR groups and the bacterial composition was also significantly changed when compared with the CON group.A similarity analysis showed that the similarities between the CON group and FR or SR group on d 7 were 48.40%or 47.85%,whereas the similarities between microbiota on d 7 and 21 in the FR and SR groups were 68.34%or 66.85%.Dry matter intake and feed efficiency were not affected by treatments.Plasmaβ-hydroxybutyrate concentration in the FR group was decreased and significantly different lipids mainly included phosphatidylcholine and lysophosphatidylcholine containing polyunsaturated fatty acids.Hepatic transcriptomics analysis indicated acutephase response pathways were upregulated in the SR group.Conclusions Our study suggests that RMT can shorten the transition process of the ruminal microbiota of postpartum dairy cows with no benefit on dry matter intake or feed efficiency.Inoculation with rumen fluid may not be a useful approach to promote the recovery of postpartum dairy cows.

Feeding Calcium Salts of Linseed Oil on Metabolic Status and Reproductive Traits in Grazing Dairy Cows

This experiment aimed to evaluate the effect of calcium salts of linseed oil (rich in alpha-linolenic acid (ALA, C18:3n-3) on metabolic and reproductive traits in high-producing dairy cows under grazing. Thirty-six Holstein dairy cows were randomly assigned, in a complete block design, to receive ALA supplementation (0.85 kg∙day−1 of calcium salts of linseed oil) or to remain as untreated control (CON). The concentrate was formulated to offer the same amount of energy across treatments (CON cows received an extra kg of corn to compensate for the higher energy density of ALA treatment). A PMR + Alfalfa pasture was offered to all cows at the same time. A fixed time artificial insemination (FTAI) at 80 DIM, preceded by a Presynch plus Ovsynch protocol was implemented for the first service and later, on return to estrus, heat detection and artificial insemination (AI) were performed. Pregnancy diagnosis was checked at 30, 42, 60, and 90 d after AI. Blood and milk samples were taken biweekly. Treatment affected plasma cholesterol concentration (160.36 vs. 186.70 mg∙dl−1, p = 0.03, for ALA and CON, respectively) and on size of corpus luteum (CL, 17.6 vs. 13.7 mm, p = 0.02, for ALA and CON, respectively). Supplementation tended (p = 0.136) to increase conception rate by 200 DIM (81.69% vs. 55.43% in ALA and CON cows, respectively). However, treatment had no effect (p > 0.05) on body weight (BW), body condition score (BCS), and circulating levels of beta-hydroxybutyrate (BHBA), glucose, insulin, growth hormone (GH) and insulin-like growth factor (IGF-I). Our results suggest that supplementation with calcium salts of linseed oil could enhance ovarian function without affecting energy metabolism in early lactation dairy cows.

Abomasal infusion of branched-chain amino acids or branched-chain keto-acids alter lactation performance and liver triglycerides in fresh cows

Background Dairy cows are at high risk of fatty liver disease in early lactation,but current preventative measures are not always effective.Cows with fatty liver have lower circulating branched-chain amino acid(BCAA)concentra-tions whereas cows with high circulating BCAA levels have low liver triglyceride(TG).Our objective was to determine the impact of BCAA and their corresponding ketoacids(branched-chain ketoacids,BCKA)on production performance and liver TG accumulation in Holstein cows in the first 3 weeks postpartum.Methods Thirty-six multiparous Holstein cows were used in a randomized block design experiment.Cows were abomasally infused for the first 21 d postpartum with solutions of 1)saline(CON,n=12);2)BCA(67 g valine,50 g leu-cine,and 34 g isoleucine,n=12);and 3)BCK(77 g 2-ketovaline calcium salt,57 g 2-ketoleucine calcium salt,and 39 g 2-ketoisoleucine calcium salt,n=12).All cows received the same diet.Treatment effects were determined using PROC GLIMMIX in SAS.Results No differences were detected for body weight,body condition score,or dry matter intake averaged over the first 21 d postpartum.Cows receiving BCK had significantly lower liver TG concentrations compared to CON(6.60%vs.4.77%,standard error of the mean(SEM)0.49)during the first 3 weeks of lactation.Infusion of BCA increased milk yield(39.5 vs.35.3 kg/d,SEM 1.8),milk fat yield(2.10 vs.1.69 kg/d,SEM 0.08),and lactose yield(2.11 vs.1.67 kg/d,SEM 0.07)compared with CON.Compared to CON,cows receiving BCA had lower plasma glucose(55.0 vs.59.2 mg/dL,SEM 0.86)but higherβ-hydroxybutyrate(9.17 vs.6.00 mg/dL,SEM 0.80).Conclusions Overall,BCAA supplementation in this study improved milk production,whereas BCKA supplementa-tion reduced TG accumulation in the liver of fresh cows.

Dietary supplementation with xylooligosaccharides and exogenous enzyme improves milk production,energy utilization efficiency and reduces enteric methane emissions of Jersey cows

Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to investigate the effects of dietary xylooligosaccharides(XOS)and exogenous enzyme(EXE)supplementation on milk production,nutrient digestibility,enteric CH_(4) emissions,energy utilization efficiency of lactating Jersey dairy cows.Forty-eight lactating cows were randomly assigned to one of 4 treatments:(1)control diet(CON),(2)CON with 25 g/d XOS(XOS),(3)CON with 15 g/d EXE(EXE),and(4)CON with 25 g/d XOS and 15 g/d EXE(XOS+EXE).The 60-d experimental period consisted of a 14-d adaptation period and a 46-d sampling period.The enteric CO_(2)and CH_(4) emissions and O2 consumption were measured using two GreenFeed units,which were further used to determine the energy utilization efficiency of cows.Results Compared with CON,cows fed XOS,EXE or XOS+EXE significantly(P<0.05)increased milk yield,true protein and fat concentration,and energy-corrected milk yield(ECM)/DM intake,which could be reflected by the significant improvement(P<0.05)of dietary NDF and ADF digestibility.The results showed that dietary supplementation of XOS,EXE or XOS+EXE significantly(P<0.05)reduced CH_(4) emission,CH_(4)/milk yield,and CH_(4)/ECM.Furthermore,cows fed XOS demonstrated highest(P<0.05)metabolizable energy intake,milk energy output but lowest(P<0.05)of CH_(4) energy output and CH_(4) energy output as a proportion of gross energy intake compared with the remaining treatments.Conclusions Dietary supplementary of XOS,EXE or combination of XOS and EXE contributed to the improvement of lactation performance,nutrient digestibility,and energy utilization efficiency,as well as reduction of enteric CH_(4) emissions of lactating Jersey cows.This promising mitigation method may need further research to validate its long-term effect and mode of action for dairy cows.

Multi‑omics reveals that the host‑microbiome metabolism crosstalk of differential rumen bacterial enterotypes can regulate the milk protein synthesis of dairy cows

Background Dairy cows’lactation performance is the outcome of the crosstalk between ruminal microbial metabo-lism and host metabolism.However,it is still unclear to what extent the rumen microbiome and its metabolites,as well as the host metabolism,contribute to regulating the milk protein yield(MPY).Methods The rumen fluid,serum and milk of 12 Holstein cows with the same diet(45%coarseness ratio),parity(2–3 fetuses)and lactation days(120–150 d)were used for the microbiome and metabolome analysis.Rumen metabolism(rumen metabolome)and host metabolism(blood and milk metabolome)were connected using a weighted gene co-expression network(WGCNA)and the structural equation model(SEM)analyses.Results Two different ruminal enterotypes,with abundant Prevotella and Ruminococcus,were identified as type1 and type2.Of these,a higher MPY was found in cows with ruminal type2.Interestingly,[Ruminococcus]gauvreauii group and norank_f_Ruminococcaceae(the differential bacteria)were the hub genera of the network.In addition,differential ruminal,serum and milk metabolome between enterotypes were identified,where the cows with type2 had higher L-tyrosine of rumen,ornithine and L-tryptophan of serum,and tetrahydroneopterin,palmitoyl-L-carnitine,S-lactoylglutathione of milk,which could provide more energy and substrate for MPY.Further,based on the identi-fied modules of ruminal microbiome,as well as ruminal serum and milk metabolome using WGCNA,the SEM analysis indicated that the key ruminal microbial module1,which contains the hub genera of the network([Ruminococcus]gauvreauii group and norank_f_Ruminococcaceae)and high abundance of bacteria(Prevotella and Ruminococcus),could regulate the MPY by module7 of rumen,module2 of blood,and module7 of milk,which contained L-tyrosine and L-tryptophan.Therefore,in order to more clearly reveal the process of rumen bacterial regulation of MPY,we established the path of SEM based on the L-tyrosine,L-tryptophan and related components.The SEM based on the metabolites suggested that[Ruminococcus]gauvreauii group could inhibit the energy supply of serum tryptophan to MPY by milk S-lactoylglutathione,which could enhance pyruvate metabolism.Norank_f_Ruminococcaceae could increase the ruminal L-tyrosine,which could provide the substrate for MPY.Conclusion Our results indicated that the represented enterotype genera of Prevotella and Ruminococcus,and the hub genera of[Ruminococcus]gauvreauii group and norank_f_Ruminococcaceae could regulate milk protein synthesis by affecting the ruminal L-tyrosine and L-tryptophan.Moreover,the combined analysis of enterotype,WGCNA and SEM could be used to connect rumen microbial metabolism with host metabolism,which provides a fundamental understanding of the crosstalk between host and microorganisms in regulating the synthesis of milk composition.

Effects of omega-3 supplementation on components of the endocannabinoid system and metabolic and inflammatory responses in adipose and liver of peripartum dairy cows

Background:Dietary supplementation of omega-3 fatty acids can reduce the activation of the endocannabinoid system(ECS)by decreasing the availability of arachidonic acid,thus lowering endocannabinoids(e CBs)levels.The ECS is a modulator of energy metabolism,stress response and inflammation in mammals,yet there is little information on the roles of the ECS in transition dairy cows.During the periparturient period,the adipose tissue and liver are the main metabolic organs that participate in the adaptations of dairy cows to onset of lactation;however,exceeded adipose tissue lipolysis and accumulation of lipids in the liver have adverse effects on cows'physiology.Here we aimed to examine whether omega-3 supplementation during the transition period will modulate ECS activation and affect metabolic and inflammatory indices in postpartum dairy cows,by supplementing twenty-eight transition Holstein dairy cows with either saturated fat(CTL)or encapsulated flaxseed oil(FLX).Components of the ECS,metabolic and inflammatory markers were measured in blood,liver,and subcutaneous adipose tissue.Results:FLX supplementation reduced feed intake by 8.1%(P<0.01)and reduced plasma levels of arachidonic acid(by 44.2%;P=0.02)and anandamide(by 49.7%;P=0.03)postpartum compared to CTL.The m RNA transcription levels of the cannabinoid receptor 1(CNR1/CB1)tended to be lower(2.5 folds)in white blood cells of FLX than in CTL(P=0.10),and protein abundance of ECS enzyme monoacylglycerol lipase was higher in peripheral blood mononuclear cells of FLX than in CTL(P=0.04).In adipose tissue,palmitoylethanolamide levels were lower in FLX than in CTL(by 61.5%;P=0.02),relative m RNA transcription of lipogenic genes were higher,and the protein abundance of cannabinoid receptor 2(P=0.08)and monoacylglycerol lipase(P=0.10)tended to be higher in FLX compared to CTL.Hepatic 2-arachidonoylglycerol tended to be higher(by 73.1%;P=0.07),and interlukin-6 m RNA transcription level was 1.5 folds lower in liver of FLX than in CTL(P=0.03).Conclusions:Nutritional supplementation of omega-3 fatty acids seems to partly modulate ECS activation,which could be related to lower feed intake.The altered ECS components in blood,adipose tissue and liver are associated with moderate modulations in lipid metabolism in the adipose and inflammation in liver of peripartum dairy cows.

Assessment of the Effects of Supplemental Rumen Protected B Vitamins and Choline for Periparturient Cows: A Meta-Analysis of 28 Feeding Studies

There are currently no prescribed requirements for B vitamins or choline for dairy cows during the transition period, but many recent studies have shown a variety of benefits from supplying these nutrients to periparturient cows. The purpose of this research effort was to determine the potential benefit of including a rumen protected blend composed of B vitamins (riboflavin, folic acid, vitamin B12) and choline (RPBlend, Jefo Nutrition Inc., St. Hyacinthe, QC, Canada) for dairy cows during the transition period, based on results from 28 on-farm feeding studies (USA-12, Mexico-7, Canada-4, Chile-3, Australia-1, Brazil-1) conducted between 2011 and 2018. All farms participated in monthly herd management record keeping systems and were selected to participate in studies due to their excellent management. Meta-analyses in which risk differences were determined were used to assess the effects of the supplemental RPBlend on health parameters and reproduction. The effect size was used as the determinant of the possible contribution of RPblend on the yields of milk, energy corrected milk (ECM), fat and protein yields during the first four weeks of lactation. Results showed that the inclusion of RPblend reduced (P < 0.05) involuntary culling and mastitis by cows during the first 30 days after calving. There was a tendency (P < 0.10) for reduced retained placenta and metritis. The meta-analyses revealed that the risk of the displaced abomasum and milk fever did not diminish (P > 0.10) with the inclusion of the BPBlend. The incidence rate of subclinical ketosis, determined as blood beta hydroxy butyric acid greater than 1.2 mM was lower (P (than those not supplemented. The proportion of cows confirmed pregnant by 100 days in milk was greater for cows given the BPBlend (P < 0.05). Milk yield and ECM were greater for cows receiving the RPBlend (1.13 and 0.93 kg/cow respectively, P < 0.05). There was no change in fat yield (P > 0.10) while the yield of milk protein was greater (P < 0.05) when the cows received the blend. These results suggest that the inclusion of rumen protected B vitamins and choline can assist cow health, reproduction and production at the start of lactation.

Predicting nitrogen use efficiency,nitrogen loss and dry matter intake of individual dairy cows in late lactation by including mid‑infrared spectra of milk samples

Background Nitrate leaching to groundwater and surface water and ammonia volatilization from dairy farms have negative impacts on the environment.Meanwhile,the increasing demand for dairy products will result in more pollution if N losses are not controlled.Therefore,a more efficient,and environmentally friendly production system is needed,in which nitrogen use efficiency(NUE)of dairy cows plays a key role.To genetically improve NUE,extensively recorded and cost-effective proxies are essential,which can be obtained by including mid-infrared(MIR)spectra of milk in prediction models for NUE.This study aimed to develop and validate the best prediction model of NUE,nitrogen loss(NL)and dry matter intake(DMI)for individual dairy cows in China.Results A total of 86 lactating Chinese Holstein cows were used in this study.After data editing,704 records were obtained for calibration and validation.Six prediction models with three different machine learning algorithms and three kinds of pre-processed MIR spectra were developed for each trait.Results showed that the coefficient of determination(R2)of the best model in within-herd validation was 0.66 for NUE,0.58 for NL and 0.63 for DMI.For external validation,reasonable prediction results were only observed for NUE,with R2 ranging from 0.58 to 0.63,while the R2 of the other two traits was below 0.50.The infrared waves from 973.54 to 988.46 cm−1 and daily milk yield were the most important variables for prediction.Conclusion The results showed that individual NUE can be predicted with a moderate accuracy in both within-herd and external validations.The model of NUE could be used for the datasets that are similar to the calibration dataset.The prediction models for NL and 3-day moving average of DMI(DMI_a)generated lower accuracies in within-herd validation.Results also indicated that information of MIR spectra variables increased the predictive ability of models.Additionally,pre-processed MIR spectra do not result in higher accuracy than original MIR spectra in the external validation.These models will be applied to large-scale data to further investigate the genetic architecture of N efficiency and further reduce the adverse impacts on the environment after more data is collected.

Integrated ribosome and proteome analyses reveal insights into sevoflurane-induced long-term social behavior and cognitive dysfunctions through ADNP inhibition in neonatal mice

A growing number of studies have demonstrated that repeated exposure to sevoflurane during development results in persistent social abnormalities and cognitive impairment.Davunetide,an active fragment of the activity-dependent neuroprotective protein(ADNP),has been implicated in social and cognitive protection.However,the potential of davunetide to attenuate social deficits following sevoflurane exposure and the underlying developmental mechanisms remain poorly understood.In this study,ribosome and proteome profiles were analyzed to investigate the molecular basis of sevoflurane-induced social deficits in neonatal mice.The neuropathological basis was also explored using Golgi staining,morphological analysis,western blotting,electrophysiological analysis,and behavioral analysis.Results indicated that ADNP was significantly down-regulated following developmental exposure to sevoflurane.In adulthood,anterior cingulate cortex(ACC)neurons exposed to sevoflurane exhibited a decrease in dendrite number,total dendrite length,and spine density.Furthermore,the expression levels of Homer,PSD95,synaptophysin,and vglut2 were significantly reduced in the sevoflurane group.Patch-clamp recordings indicated reductions in both the frequency and amplitude of miniature excitatory postsynaptic currents(mEPSCs).Notably,davunetide significantly ameliorated the synaptic defects,social behavior deficits,and cognitive impairments induced by sevoflurane.Mechanistic analysis revealed that loss of ADNP led to dysregulation of Ca^(2+)activity via the Wnt/β-catenin signaling,resulting in decreased expression of synaptic proteins.Suppression of Wnt signaling was restored in the davunetide-treated group.Thus,ADNP was identified as a promising therapeutic target for the prevention and treatment of neurodevelopmental toxicity caused by general anesthetics.This study provides important insights into the mechanisms underlying social and cognitive disturbances caused by sevoflurane exposure in neonatal mice and elucidates the regulatory pathways involved.

Evaluation of Holstein cows with different tongue‑rolling frequencies:stress immunity,rumen environment and general behavioural activity

Background The tongue-rolling behaviour of cows is regarded as an outward sign of stressed animals in a low welfare status.The primary aim of this observational study was to evaluate the association between the frequency of tongue-rolling behaviour and its physiological function.The secondary aim was to explore the relationship between general activities and the frequency of tongue-rolling behaviour of cows.A total of 126 scan sampling behavioural observations were collected over 7 d on 348 Holstein cows with the same lactation stage in the same barn.The tongue-rolling frequency was defined as the number of tongue-rolling observations as a percentage to the total observations per individual cow.According to their tongue-rolling frequency,the cows were grouped into the CON(no tongue-rolling),LT(frequency 1%),MT(frequency 5%),and HT(frequency 10%)groups.Six cows from each group were randomly selected for sampling.Serum samples,rumen fluid,milk yield,and background infor-mation were collected.The general behaviour data during 72 continuous hours of dairy cows,including eating time,rumination time,food time(eating time+rumination time),and lying time,were recorded by the collar sensor.Results Cortisol(P=0.012),γ-hydroxybutyric acid(P=0.008),epinephrine(P=0.030),and dopamine(P=0.047)levels were significantly higher in tongue-rolling groups than in the CON group.Cortisol levels and tongue-rolling frequency had a moderate positive correlation(linearly r=0.363).With the increase in tongue-rolling frequency,the rumen pH decreased first and then increased(P=0.013),comparing to the CON group.HT cows had significantly less food time than CON cows(P=0.035).The frequency of tongue-rolling had a moderate negative relationship with rumination time(r=-0.384)and food time(r=-0.492).Conclusions The tongue-rolling behaviour is considered as a passive coping mechanism,as the stress response in cows with high tongue-rolling frequency increased.Food intake and rumination activities were all closely related to the occurrence of tongue-rolling behaviour.

The effect of ensiled paulownia leaves in a high-forage diet on ruminal fermentation,methane production,fatty acid composition,and milk production performance of dairy cows

Background:The use of industrial by-products rich in bioactive compounds as animal feeds can reduce greenhouse gas production.Paulownia leaves silage(PLS)was supplemented to dairy cows'diet and evaluated in vitro(Exp.1;Rusitec)and in vivo(Exp.2,cannulated lactating dairy cows and Exp.3,non-cannulated lactating dairy cows).The study investigated the PLS effect on ruminal fermentation,microbial populations,methane production and concentration,dry matter intake(DMI),and fatty acid(FA)proportions in ruminal fluid and milk.Results:Several variables of the ruminal fluid were changed in response to the inclusion of PLS.In Exp.1,the p H increased linearly and quadratically,whereas ammonia and total volatile fatty acid(VFA)concentrations increased linearly and cubically.A linear,quadratic,and cubical decrease in methane concentration was observed with increasing dose of the PLS.Exp.2 revealed an increase in ruminal p H and ammonia concentrations,but no changes in total VFA concentration.Inclusion of PLS increased ruminal propionate(at 3 h and 6 h after feeding),isovalerate,and valerate concentrations.Addition of PLS also affected several populations of the analyzed microorganisms.The abundances of protozoa and bacteria were increased,whereas the abundance of archaea were decreased by PLS.Methane production decreased by 11%and 14%in PLS-fed cows compared to the control in Exp.2 and 3,respectively.Exp.3 revealed a reduction in the milk protein and lactose yield in the PLS-fed cows,but no effect on DMI and energy corrected milk yield.Also,the PLS diet affected the ruminal biohydrogenation process with an increased proportions of C18:3 cis-9 cis-12 cis-15,conjugated linoleic acid,C18:1 trans-11 FA,polyunsaturated fatty acids(PUFA),and reduced n6/n3 ratio and saturated fatty acids(SFA)proportion in milk.The relative transcript abundances of the 5 of 6 analyzed genes regulating FA metabolism increased.Conclusions:The dietary PLS replacing the alfalfa silage at 60 g/kg diet can reduce the methane emission and improve milk quality with greater proportions of PUFA,including conjugated linoleic acid,and C18:1 trans-11 along with reduction of SFA.

A Comparative Study on the Post-Buckling Behavior of Reinforced Thermoplastic Pipes(RTPs)Under External Pressure Considering Progressive Failure

The collapse pressure is a key parameter when RTPs are applied in harsh deep-water environments.To investigate the collapse of RTPs,numerical simulations and hydrostatic pressure tests are conducted.For the numerical simulations,the eigenvalue analysis and Riks analysis are combined,in which the Hashin failure criterion and fracture energy stiffness degradation model are used to simulate the progressive failure of composites,and the“infinite”boundary conditions are applied to eliminate the boundary effects.As for the hydrostatic pressure tests,RTP specimens were placed in a hydrostatic chamber after filled with water.It has been observed that the cross-section of the middle part collapses when it reaches the maximum pressure.The collapse pressure obtained from the numerical simulations agrees well with that in the experiment.Meanwhile,the applicability of NASA SP-8007 formula on the collapse pressure prediction was also discussed.It has a relatively greater difference because of the ignorance of the progressive failure of composites.For the parametric study,it is found that RTPs have much higher first-ply-failure pressure when the winding angles are between 50°and 70°.Besides,the effect of debonding and initial ovality,and the contribution of the liner and coating are also discussed.

Neurophysiological, histological, and behavioral characterization of animal models of distraction spinal cord injury: a systematic review

Distraction spinal cord injury is caused by some degree of distraction or longitudinal tension on the spinal cord and commonly occurs in patients who undergo corrective operation for severe spinal deformity.With the increased degree and duration of distraction,spinal cord injuries become more serious in terms of their neurophysiology,histology,and behavior.Very few studies have been published on the specific characteristics of distraction spinal cord injury.In this study,we systematically review 22 related studies involving animal models of distraction spinal cord injury,focusing particularly on the neurophysiological,histological,and behavioral characteristics of this disease.In addition,we summarize the mechanisms underlying primary and secondary injuries caused by distraction spinal cord injury and clarify the effects of different degrees and durations of distraction on the primary injuries associated with spinal cord injury.We provide new concepts for the establishment of a model of distraction spinal cord injury and related basic research,and provide reference guidelines for the clinical diagnosis and treatment of this disease.

Spatially resolved transcriptomic profiling of placental development in dairy cow

The placenta plays a crucial role in successful mammalian reproduction.Ruminant animals possess a semi-invasive placenta characterized by a highly vascularized structure formed by maternal endometrial caruncles and fetal placental cotyledons,essential for full-term fetal development.The cow placenta harbors at least two trophoblast cell populations:uninucleate(UNC)and binucleate(BNC)cells.However,the limited capacity to elucidate the transcriptomic dynamics of the placental natural environment has resulted in a poor understanding of both the molecular and cellular interactions between trophoblast cells and niches,and the molecular mechanisms governing trophoblast differentiation and functionalization.To fill this knowledge gap,we employed Stereo-seq to map spatial gene expression patterns at near single-cell resolution in the cow placenta at 90 and 130 days of gestation,attaining high-resolution,spatially resolved gene expression profiles.Based on clustering and cell marker gene expression analyses,key transcription factors,including YBX1 and NPAS2,were shown to regulate the heterogeneity of trophoblast cell subpopulations.Cell communication and trajectory analysis provided a framework for understanding cell-cell interactions and the differentiation of trophoblasts into BNCs in the placental microenvironment.Differential analysis of cell trajectories identified a set of genes involved in regulation of trophoblast differentiation.Additionally,spatial modules and co-variant genes that help shape specific tissue structures were identified.Together,these findings provide foundational insights into important biological pathways critical to the placental development and function in cows.

Unveiling the brain’s symphony:exploring the necessity and sufficiency of neural networks in behavior control

Since the pioneering work by Broca and Wernicke in the 19th century,who examined individuals with brain lesions to associate them with specific behaviors,it was evident that behaviors are complex and cannot be fully attributable to specific brain areas alone.Instead,they involve connectivity among brain areas,whether close or distant.At that time,this approach was considered the optimal way to dissect brain circuitry and function.These pioneering efforts opened the field to explore the necessity or sufficiency of brain areas in controlling behavior and hence dissecting brain function.However,the connectivity of the brain and the mechanisms through which various brain regions regulate specific behaviors,either individually or collaboratively,remain largely elusive.Utilizing animal models,researchers have endeavored to unravel the necessity or sufficiency of specific brain areas in influencing behavior;however,no clear associations have been firmly established.

Cluster DetectionMethod of Endogenous Security Abnormal Attack Behavior in Air Traffic Control Network

In order to enhance the accuracy of Air Traffic Control(ATC)cybersecurity attack detection,in this paper,a new clustering detection method is designed for air traffic control network security attacks.The feature set for ATC cybersecurity attacks is constructed by setting the feature states,adding recursive features,and determining the feature criticality.The expected information gain and entropy of the feature data are computed to determine the information gain of the feature data and reduce the interference of similar feature data.An autoencoder is introduced into the AI(artificial intelligence)algorithm to encode and decode the characteristics of ATC network security attack behavior to reduce the dimensionality of the ATC network security attack behavior data.Based on the above processing,an unsupervised learning algorithm for clustering detection of ATC network security attacks is designed.First,determine the distance between the clustering clusters of ATC network security attack behavior characteristics,calculate the clustering threshold,and construct the initial clustering center.Then,the new average value of all feature objects in each cluster is recalculated as the new cluster center.Second,it traverses all objects in a cluster of ATC network security attack behavior feature data.Finally,the cluster detection of ATC network security attack behavior is completed by the computation of objective functions.The experiment took three groups of experimental attack behavior data sets as the test object,and took the detection rate,false detection rate and recall rate as the test indicators,and selected three similar methods for comparative test.The experimental results show that the detection rate of this method is about 98%,the false positive rate is below 1%,and the recall rate is above 97%.Research shows that this method can improve the detection performance of security attacks in air traffic control network.

脉冲电沉积CoW/ZrO_(2)复合镀层的力学性能研究

研究了镀液中ZrO_(2)纳米颗粒添加量对COW/ZrO_(2)复合镀层质量和摩擦磨损性能的影响。采用单因素试验法,在一定条件下改变镀液中ZrO_(2)纳米颗粒的添加量从而获得不同的COW/ZrO_(2)复合镀层。用扫描电子显微镜SU5000观察镀层表面形貌,用X射线衍射和表面分析仪P7分别检测镀层的微观结构、厚度和表面粗糙度,研究镀层表面质量随镀液中ZrO_(2)纳米颗粒添加量的变化规律并测试镀层的摩擦学性能。试验结果表明:在一定条件下镀液中ZrO_(2)纳米颗粒的添加量对复合镀层质量的影响存在最优值,镀液中ZrO_(2)含量的变化对于镀层磨损率的减小存在最优值。采用脉冲电沉积法制备COW/ZrO_(2)复合镀层的过程中,ZrO_(2)纳米颗粒添加量为9g/L时复合镀层的表面质量和耐磨性最好。

Prospect Theory Based Individual Irrationality Modelling and Behavior Inducement in Pandemic Control

Understanding and modeling individuals’behaviors during epidemics is crucial for effective epidemic control.However,existing research ignores the impact of users’irrationality on decision-making in the epidemic.Meanwhile,existing disease control methods often assume users’full compliance with measures like mandatory isolation,which does not align with the actual situation.To address these issues,this paper proposes a prospect theorybased framework to model users’decision-making process in epidemics and analyzes how irrationality affects individuals’behaviors and epidemic dynamics.According to the analysis results,irrationality tends to prompt conservative behaviors when the infection risk is low but encourages risk-seeking behaviors when the risk is high.Then,this paper proposes a behavior inducement algorithm to guide individuals’behaviors and control the spread of disease.Simulations and real user tests validate our analysis,and simulation results show that the proposed behavior inducement algorithm can effectively guide individuals’behavior.

Coke behavior with H_(2)O in a hydrogen-enriched blast furnace:A review

Hydrogen-enriched blast furnace ironmaking has become an essential route to reduce CO_(2)emissions in the ironmaking process.However,hydrogen-enriched reduction produces large amounts of H_(2)O,which places new demands on coke quality in a blast furnace.In a hydrogen-rich blast furnace,the presence of H_(2)O promotes the solution loss reaction.This result improves the reactivity of coke,which is 20%-30%higher in a pure H_(2)O atmosphere than in a pure CO_(2)atmosphere.The activation energy range is 110-300 kJ/mol between coke and CO_(2)and 80-170 kJ/mol between coke and H_(2)O.CO_(2)and H_(2)O are shown to have different effects on coke degradation mechanisms.This review provides a comprehensive overview of the effect of H_(2)O on the structure and properties of coke.By exploring the interactions between H_(2)O and coke,several unresolved issues in the field requiring further research were identified.This review aims to provide valuable insights into coke behavior in hydrogen-rich environments and promote the further development of hydrogen-rich blast furnace ironmaking processes.