Effects of freeze-thaw cycles on sandstone in sunny and shady slopes

A growing rock engineering activity in cold regions is facing the threat of freeze-thaw(FT)weathering,especially in high mountains where the sunny-shady slope effects strongly control the difference in weathering behavior of rocks.In this paper,an investigation of the degradation of petrophysical characteristics of sandstone specimens subjected to FT cycle tests to simulate the sunny-shady slope effects is presented.To this aim,non-destructive and repeatable testing techniques including weight,ultrasonic waves,and nuclear magnetic resonance methods on standard specimens were performed.For the sunny slope specimens,accompanied by the enlargement of small pores,100 FT cycles caused a significant decrease in P-wave velocity with an average of 23%,but a consistent rise of 0.18%in mass loss,34%in porosity,67%in pore geometrical mean radius,and a remarkable 14.5-fold increase in permeability.However,slight changes with some abnormal trends in physical parameters of the shady slope specimens were observed during FT cycling,which can be attributed to superficial granular disaggregation and pore throat obstruction.Thermal shocks enhance rock weathering on sunny slopes during FT cycles,while FT weathering on shady slopes is restricted to the small pores and the superficial cover.These two factors are primarily responsible for the differences in FT weathering intensity between sunny and shady slopes.The conclusions derived from the interpretation of the experimental results may provide theoretical guidance for the design of slope-failure prevention measures and the selection of transportation routes in cold mountainous regions.

Speech Separation Algorithm Using Gated Recurrent Network Based on Microphone Array

Speech separation is an active research topic that plays an important role in numerous applications,such as speaker recognition,hearing pros-thesis,and autonomous robots.Many algorithms have been put forward to improve separation performance.However,speech separation in reverberant noisy environment is still a challenging task.To address this,a novel speech separation algorithm using gate recurrent unit(GRU)network based on microphone array has been proposed in this paper.The main aim of the proposed algorithm is to improve the separation performance and reduce the computational cost.The proposed algorithm extracts the sub-band steered response power-phase transform(SRP-PHAT)weighted by gammatone filter as the speech separation feature due to its discriminative and robust spatial position in formation.Since the GRU net work has the advantage of processing time series data with faster training speed and fewer training parameters,the GRU model is adopted to process the separation featuresof several sequential frames in the same sub-band to estimate the ideal Ratio Masking(IRM).The proposed algorithm decomposes the mixture signals into time-frequency(TF)units using gammatone filter bank in the frequency domain,and the target speech is reconstructed in the frequency domain by masking the mixture signal according to the estimated IRM.The operations of decomposing the mixture signal and reconstructing the target signal are completed in the frequency domain which can reduce the total computational cost.Experimental results demonstrate that the proposed algorithm realizes omnidirectional speech sep-aration in noisy and reverberant environments,provides good performance in terms of speech quality and intelligibility,and has the generalization capacity to reverberate.

有机修饰剂对环氧树脂/粘土纳米复合材料结构的影响

分别用质子化的2,4,6-三(二甲氨基甲基)苯酚(HDMP30)、质子化的十八胺(HODA)及氯化胆碱(CC)作为有机修饰剂对原始粘土进行改性,通过"粘土淤浆复合法"合成了环氧树脂/粘土纳米复合材料。采用透射电镜及X射线衍射研究了"粘土淤浆复合法"工艺中有机修饰剂的种类对环氧树脂/粘土纳米复合材料微观结构的影响。结果表明,憎水性的HODA改性粘土所制备的纳米复合材料只能形成插层结构;带有亲水基团羟基的CC改性粘土为剥离与插层混合型结构;而既带有亲水基团又与环氧预聚体有良好相容性的HDMP30改性的粘土则可形成高度无规剥离结构。阐明了3种不同类型有机修饰剂改性粘土所导致的不同微观结构形成的机理。

一类含四甲氧基芴结构可溶性聚酰亚胺的合成及表征

通过三步有机反应合成了一种新型含四甲氧基芴结构的芳香型二胺单体——9,9-双(3,5-二甲氧基-4-(4-氨基苯氧基)苯基)芴,由这种单体分别与4种商品化芳香二酐经过高温缩聚反应,制得一系列含芴结构聚酰亚胺(PI 4a^4d)。分别用傅里叶红外光谱、核磁共振波谱、差示扫描量热及热失重分析等对聚合物的结构和性能进行了表征和研究。该类聚酰亚胺在甲基吡咯烷酮(NMP)、二甲基乙酰胺(DMAc)、二甲基甲酰胺(DMF)、二甲基亚砜(DMSO)等高沸点溶剂及CHCl_3、CH_2Cl_2等低沸点溶剂中具有优异的溶解性;所制得的薄膜具有良好的力学性能,其拉伸强度为62.1~75.6 MPa,断裂伸长率在16.0%~20.7%之间,弹性模量为1.8~2.6 GPa。该系列聚酰亚胺的玻璃化转变温度在244~256℃之间,空气和氮气中10%热失重温度均在430℃以上,表现出优异的热学性能。

Comparative efficacy of various exercise interventions on cognitive function in patients with mild cognitive impairment or dementia:A systematic review and network meta-analysis

Background:Exercise is a promising nonpharmacological therapy for cognitive dysfunction,but it is unclear which type of exercise is most effective.The objective of this study was to compare and rank the effectiveness of various exercise interventions on cognitive function in patients with mild cognitive impairment(MCI)or dementia and to examine the effects of exercise on the symptoms relevant to cognitive impairment.Methods:We searched PubMed,Web of Science,Embase,Cochrane Central Register of Controlled Trials,SPORTDiscus,and PsycInfo through September 2019 and included randomized controlled trials that examined the effectiveness of exercise interventions in patients with MCI or dementia.Primary outcomes included global cognition,executive cognition,and memory cognition.Secondary outcomes included activities of daily living,neuropsychiatric symptoms,and quality of life.Pairwise analyses and network meta-analyses were performed using a random effects model.Results:A total of 73 articles from 71 trials with 5606 participants were included.All types of exercise were effective in increasing or maintaining global cognition,and resistance exercise had the highest probability of being the most effective intervention in slowing the decrease in global cognition(standard mean difference(SMD)=1.05,95%confidence interval(95%CI):0.56-1.54),executive function(SMD=0.85,95%CI:0.21-1.49),and memory function(SMD=0.32,95%CI:0.01-0.63)in patients with cognitive dysfunction.Subgroup analyses for patients with MCI revealed different effects,and multicomponent exercise was most likely to be the optimal exercise therapy for preventing the decline of global cognition(SMD=0.99,95%CI:0.44-1.54)and executive function(SMD=0.72,95%CI:0.06-1.38).However,only resistance exercise showed significant effects on memory function for patients with MCI(SMD=0.35,95%CI:0.01-0.69).Exercise interventions also showed various effects on the secondary outcomes.Conclusion:Resistance exercise has the highest probability of being the optimal exercise type for slowing cognitive declin e in patients withcognitive dysfunction,especially in patients with dementia.Multicomponent exercise tends to be most effective in protecting global cognition and executive function in patients with MCI.

一种不对称芳香二胺单体及其聚酰亚胺的合成与表征

利用2,5-二溴三氟甲苯和3-硝基苯硼酸等为起始原料,经过简捷的2步有机反应,成功合成了一种含三氟甲基结构的不对称芳香二胺单体--2,5-二(3-氨基苯)-1-三氟甲苯。利用这种不对称芳香二胺单体分别与4种不同的商品化芳香二酐(联苯酐、醚酐、砜酐、酮酐)采用一步法高温缩聚制备了一系列含不对称结构的新型聚酰亚胺(PI 4a^PI 4d)。利用红外和核磁表征了所制二胺单体及聚酰亚胺的分子结构。4种聚酰亚胺中,PI 4b^PI 4d在室温可溶解于DMAc、NMP、DMSO等强极性高沸点溶剂中,并可方便地利用其聚合物溶液涂覆得到聚合物薄膜;其中PI 4b还可以溶于CHCl3、CH2Cl2等低沸点溶剂中。该类聚酰亚胺具有良好的热学性能,在N2和O2氛围中5%热质量损失温度都在498℃以上,玻璃化转变温度在240℃以上。所制聚酰亚胺薄膜拉伸强度在77.4~88.6 MPa范围,弹性模量为2.0~2.9 GPa,断裂伸长率在4.9%~9.9%。另外,该类聚合物薄膜在450 nm波长光下的透光率在67%以上,截止波长在329~357 nm,表现出较好的光学透明性。

Combined genomic, transcriptomic, and metabolomic an alyses provide in sights into chayote (Sechium edule) evolution and fruit development

Chayote(Sechium edule)is an agricultural crop in the Cucurbitaceae family that is rich in bioactive components.To enhance genetic research on chayote,we used Nanopore third-generation sequencing combined with Hi-C data to assemble a draft chayote genome.A chromosome-level assembly anchored on 14 chromosomes(N50 contig and scaffold sizes of 8.40 and 46.56 Mb,respectively)estimated the genome size as 606.42 Mb,which is large for the Cucurbitaceae,with 65.94%(401.08 Mb)ofthe genome comprising repetitive sequences;28,237 protein-coding genes were predicted.Comparative genome analysis indicated that chayote and snake gourd diverged from sponge gourd and that a whole-genome duplication(WGD)event occurred in chayote at 25±4 Mya.Transcriptional and metabolic analysis revealed genes involved in fruit texture,pigment,fl avor,fl avonoids,antioxidants,and plant hormones during chayote fruit development.The analysis of the genome,transcriptome,and metabolome provides insights into chayote evolution and lays the groundwork for future research on fruit and tuber development and genetic improvements in chayote.

一类含双叔丁基苯结构聚酰亚胺的合成与性能

通过分子设计制备一种含双叔丁基结构的刚性芳香二胺单体——4,4′-二氨基苯基-3″,5″-二叔丁基甲苯,将该二胺单体分别与3种不同的商品化芳香二酐(3,3′,4,4′-联苯四酸二酐(BPDA)、3,3′,4,4′-二苯醚酐(ODPA)、3,3′,4,4′-二苯酮四酸二酐(BTDA))采用一步高温缩聚制备了3种新型聚酰亚胺NPI(3a~3c)。该类聚酰亚胺具有优异的溶解成膜性能,在室温可溶解于N-甲基-2-吡咯烷酮、N,N-二甲基乙酰胺、间甲酚等高沸点溶剂中,在加热时还能溶解于CHCl_(3),CH_(2)Cl_(2),THF等低沸点溶剂,并可通过其聚合物溶液浇铸得到柔韧的薄膜;所制聚酰亚胺薄膜具有优良的热性能,玻璃化转变温度(T_(g))范围为262~303℃,在N_(2)中质量损失10%的温度超过523℃;具有优异的光学性能,所制薄膜还具有较浅的颜色和良好的光学透过性,在450 nm波长光下的透光率为69%~76%,截止波长为341~353 nm。

Sound Source Localization Based on SRP-PHAT Spatial Spectrum and Deep Neural Network

Microphone array-based sound source localization(SSL)is a challenging task in adverse acoustic scenarios.To address this,a novel SSL algorithm based on deep neural network(DNN)using steered response power-phase transform(SRP-PHAT)spatial spectrum as input feature is presented in this paper.Since the SRP-PHAT spatial power spectrum contains spatial location information,it is adopted as the input feature for sound source localization.DNN is exploited to extract the efficient location information from SRP-PHAT spatial power spectrum due to its advantage on extracting high-level features.SRP-PHAT at each steering position within a frame is arranged into a vector,which is treated as DNN input.A DNN model which can map the SRP-PHAT spatial spectrum to the azimuth of sound source is learned from the training signals.The azimuth of sound source is estimated through trained DNN model from the testing signals.Experiment results demonstrate that the proposed algorithm significantly improves localization performance whether the training and testing condition setup are the same or not,and is more robust to noise and reverberation.

The genome and transcriptome analysis of snake gourd provide insights into its evolution and fruit development and ripening

Snake gourd(Trichosanthes anguina L.),which belongs to the Cucurbitaceae family,is a popular ornamental and food crop species with medicinal value and is grown in many parts of the world.Although progress has been made in its genetic improvement,the organization,composition,and evolution of the snake gourd genome remain largely unknown.Here,we report a high-quality genome assembly for snake gourd,comprising 202 contigs,with a total size of 919.8 Mb and an N50 size of 20.1 Mb.These findings indicate that snake gourd has one of the largest genomes of Cucurbitaceae species sequenced to date.The snake gourd genome assembly harbors 22,874 protein-coding genes and 80.0%of the genome consists of repetitive sequences.Phylogenetic analysis reveals that snake gourd is closely related to sponge gourd but diverged from their common ancestor~33–47 million years ago.The genome sequence reported here serves as a valuable resource for snake gourd genetic research and comparative genomic studies in Cucurbitaceae and other plant species.In addition,fruit transcriptome analysis reveals the candidate genes related to quality traits during snake gourd fruit development and provides a basis for future research on snake gourd fruit development and ripening at the transcript level.

Application of ITS2 Sequence as DNA Barcode in Xanthium

[ Objective ] Xanthium plants （non-Chinese species） are quarantine pests in China. This study aimed to distinguish and identify seven Xanthium spe- cies using ITS2 sequence as DNA barcode. [Method] ITS2 gene was amplified using universal primers to obtain ITS2 sequences of seven Xanthium species, which were then sequenced. ITS2 sequences of seven Xanthium species were compared and analyzed by MEGA 5.1 software, and the phylogenetic tree was constructed. [ Result] A total of 242 variable sites were found in 1TS2 sequences of Xanthium species, including 12 singleton variable sites. [ Conclusion] Xanthium species can be distinguished and identified based on ITS2 sequences.

Microphone Array-Based Sound Source Localization Using Convolutional Residual Network

Microphone array-based sound source localization(SSL)is widely used in a variety of occasions such as video conferencing,robotic hearing,speech enhancement,speech recognition and so on.The traditional SSL methods cannot achieve satisfactory performance in adverse noisy and reverberant environments.In order to improve localization performance,a novel SSL algorithm using convolutional residual network(CRN)is proposed in this paper.The spatial features including time difference of arrivals(TDOAs)between microphone pairs and steered response power-phase transform(SRPPHAT)spatial spectrum are extracted in each Gammatone sub-band.The spatial features of different sub-bands with a frame are combine into a feature matrix as the input of CRN.The proposed algorithm employ CRN to fuse the spatial features.Since the CRN introduces the residual structure on the basis of the convolutional network,it reduce the difficulty of training procedure and accelerate the convergence of the model.A CRN model is learned from the training data in various reverberation and noise environments to establish the mapping regularity between the input feature and the sound azimuth.Through simulation verification,compared with the methods using traditional deep neural network,the proposed algorithm can achieve a better localization performance in SSL task,and provide better generalization capacity to untrained noise and reverberation.

Research Status and Application Prospect of Aluminum Matrix Composites

Aluminum matrix composite is one of the most attractive metal matrix composites.It is a kind of material with strong vitality emerging in response to the needs of modern scientific development.Compared with traditional materials,aluminum matrix composites have the advantages of low density,good electric conductivity and heat conductivity,good wear resistance and oxidation resistance,high specific strength and stiffness,high temperature resistance,good heat treatment performance and flexible preparation process,which make them widely used in the fields of aviation,aerospace,and automobile.In this paper,the factors affecting the properties of aluminum matrix composites,the strengthening mechanism,classification and preparation methods of aluminum matrix composites are summarized.The research status,development direction and application prospect of aluminum matrix composites are briefly introduced.

Identification of Original Plants, Traits, Microstructure and Powder of Leontopodium franchetii Beauv.

[Objectives] This study aimed to provide experimental data for the identification and application of Leontopodium franchetii Beauv. [Methods] The original plants, traits, microstructure and powder of L. franchetii Beauv. were identified. [Results] The identification characteristics of L. franchetii Beauv. in the original plants, traits and microstructure were obvious. [Conclusions] This study can provide reference for the identification of original plants and herbs and the development of quality standards of L. franchetii Beauv. and provide a basis for further research and development.

Discovery of Digenic Mutation, KCNH2 c.1898A > C and JUP c.916dupA, in a Chinese Family with Long QT Syndrome via Whole-Exome Sequencing

Long QT syndrome(LQTS),which is caused by an ion channel–related gene mutation,is a malignant heart disease with a clinical course of a high incidence of ventricular fi brillation and sudden cardiac death in the young.Mutations in KCNH2(which encodes potassium voltage-gated channel subfamily H member 2)are responsible for LQTS in many patients.Here we report the novel mutation c.1898A>C in KCNH2 in a Chinese family with LQTS through whole-exome sequencing.The c.916dupA mutation in JUP(which encodes junction plakoglobin)is also discovered.Mutations in JUP were found to be associated with arrhythmogenic right ventricular cardiomyopathy.The double mutation in the proband may help explain his severe clinical manifestations,such as sudden cardiac death at an early age.Sequencing for the proband’s family members revealed that the KCNH2 mutation descends from his paternal line,while the mutation in JUP came from his maternal line.The data provided in this study may help expand the spectrum of LQTS-related KCNH2 mutations and add support to the genetic diagnosis and counseling of families affected by malignant arrhythmias.

Identifi cation of Three FBN1 Mutations in Chinese Patients with Typical or Incomplete Marfan Syndrome by Whole-Exome Sequencing

Objective:The purpose of this work was to obtain the phenotypes and detect potential mutations in three Chinese patients with Marfan syndrome(MFS)or incomplete MFS phenotypes.Methods:Three unrelated patients with a defi nite or suspected clinical diagnosis of MFS and their family members were recruited for research.Genomic DNA was extracted from peripheral blood of these patients and their family members.All the exons were sequenced by next-generation sequencing and the variants were further validated by Sanger sequencing.The functional consequences of the mutations were analyzed with various genomic resources and bioinformatics tools.Results:Three FBN1 mutations were identifi ed in the three patients,including one novel mutation(2125G>A)and two previously reported mutations(4786C>T and 6325C>T).It was interesting to note that the parents of these patients were normal as assessed by clinical features or genetic testing,but all these mutations were detected in their offspring,except for the variant 6325C>T.We also found that a few young members of the family of probands(proband 1 and proband 2)have exhibited no manifestations of MFS so far,although they carry the same disease-causing mutation.Conclusions:We found three FBN1 mutations in three unrelated Chinese families with MFS by genome sequencing,and the relationship between genotypes and phenotypes in MFS patients needs further exploration.

Identifi cation of Novel TTN Mutations in Three Chinese Familial Dilated Cardiomyopathy Pedigrees by Whole Exome Sequencing

Familial dilated cardiomyopathy(DCM)is associated with numerous genes,especially those of the sarcomere family.The titin gene(TTN)consists of 365 exons and encodes the largest sarcomere protein(titin)in our bodies.Titin is associated with many diseases,such as hypertrophic cardiomyopathy and DCM.Here we screened three Chinese families affected by DCM,and found that each harbors a stop-gain or splice site mutation in TTN(c.G20137T,c.G52522T,c.44610-2A>C).Assessment of the probands by electrocardiogram,B-mode echocardiography,and cardiac magnetic resonance imaging revealed impaired cardiac function,arrhythmia,or abnormal cardiac structure.In conclusion,using whole exome sequencing,we found three unreported TTN mutations associated with DCM.This has expanded the TTN mutation spectrum of Chinese DCM patients,especially in Henan,the most populous province.These data provide new genetic targets for the diagnosis and treatment of DCM,and will increase our understanding of the relationship between TTN mutation and DCM clinical symptoms.

Syntheses and Adsorption Property Research of N-Diethyl Imidazole Modified PS Resins for Iodine

A new N-diethyl imidazole modified PS resins was synthesized in this paper. The composition, structure, and properties of the resulting resins were studied by means of Fourier transform infrared (FTIR) and elemental analysis methods. The results showed that the resins hold the adsorption function group of quaternary ammonium structure. Meanwhile, the adsorption properties of the resulting resins for iodine were investigated. The results showed that the uptake of iodine found to be higher at natural water than at acidic medium;the adsorption capacity increased with the increasing of temperature, but when the temperature is higher than 30°C, adsorption capacity didn’t increase;the adsorption kinetics of the resins can be modeled by pseudo first-order rate equation and pseudo second-order rate equation wonderfully;Both Freundlich equations and Langmuir equations could well interpret the adsorption of resins for iodine.

Application Strategy of BIM Technology in Virtual Construction of Prefabricated Buildings

In order to improve the construction efficiency,save resources,reduce costs,and to protect the environment during the construction work,prefabricated buildings is an important process that is needed to be carried out during the construction.However,in the current situation,lack of knowledge related the prefabricated buildings,and irrationalities of the relevant staff,limits the practical application of the prefabricated buildings.Simulating construction through building information modeling(BIM),can fully simulate various situations that may occur in the construction process,and also can improve the quality and efficiency of the prefabricated building construction work,therefore,this paper analyzes the application strategy of BIM technology in the virtual construction of prefabricated buildings as a reference.

Establishment of a Lateral Flow Dipstick Detection Method for Influenza A Virus Based on CRISPR/Cas12a System

Objective:This study aimed to develop a rapid,visual PCR-CRISPR/Cas12-LFD method for detecting influenza A by utilizing the conserved region of the matrix protein gene.Method:We crafted universal degradation primers and clustered regularly interspaced short palindromic repeats RNA(CRISPR RNA,crRNA)targeting the conserved matrix protein gene of the influenza virus(IFV),integrated with lateral flow dipstick(LFD)technology.This new PCR-CRISPR/Cas12-LFD approach was designed to determine its sensitivity and specificity through the analysis of various clinical samples collected in 2023.Results:The developed nucleic acid assay for influenza A viruses(IAV)demonstrated a sensitivity of 10 copies/μL without cross-reactivity with other respiratory pathogens.Evaluation of 82 clinical samples showed high concordance with results from fluorescent Polymerase Chain Reaction(PCR),achieving a kappa value of 0.95.Conclusion:A highly sensitive and specific PCRCRISPR/Cas12-LFD method has been successfully established for the detection of influenza A,offering a robust tool for its diagnosis and aiding in the prevention and control of this virus.