Therapeutic interventions target the NLRP3 inflammasome in ulcerative colitis:Comprehensive study

One of the significant health issues in the world is the prevalence of ulcerative colitis(UC).UC is a chronic disorder that mainly affects the colon,beginning with the rectum,and can progress from asymptomatic mild inflammation to extensive inflammation of the entire colon.Understanding the underlying molecular mechanisms of UC pathogenesis emphasizes the need for innovative therapeutic approaches based on identifying molecular targets.Interestingly,in response to cellular injury,the NLR family pyrin domain containing 3(NLRP3)inflammasome is a crucial part of the inflammation and immunological reaction by promoting caspase-1 activation and the release of interleukin-1β.This review discusses the mechanisms of NLRP3 inflammasome activation by various signals and its regulation and impact on UC.

Helically symmetric equilibria for some ideal and resistive MHD plasmas with incompressible flows

In this paper, the problem of finding exact solutions to the magnetohydrodynamic(MHD) equations in the presence of incompressible mass flows with helical symmetry is considered. For ideal flows, a similarity reduction method is used to obtain exact solutions for several MHD flows with nonlinear variable Mach number. For resistive flows parallel to a magnetic field, the governing equilibrium equation is derived. The MHD equilibrium state of a helically symmetric incompressible flow is governed by a second-order elliptic partial differential equation(PDE) for the helical magnetic flux function. Exact solutions for the latter equation are obtained. Also, the equilibrium equations of a gravitating plasma with incompressible flow are derived.

Effectiveness and safety of subthreshold vibration over suprathreshold vibration in treatment of muscle fatigue in elderly people

Muscle fatigue is common in many populations,particularly elderlies.Aging increases the incidence of muscle fatigue and delays its recovery.There is a huge debate about the current treatments for muscle fatigue,particularly in elderlies.Recently,it has been discovered that mechanoreceptors have an important role as a sensory system in sensing muscle fatigue which could enhance the body's response to muscle fatigue.The function of mechanoreceptors could be enhanced by applying either suprathreshold or subthreshold vibration.Although suprathreshold vibration improves muscle fatigue,it can cause desensitization of cutaneous receptors,discomfort,and paresthesia,which are barriers to clinical use.Subthreshold vibration has been approved as a safe and effective method of training for mechanoreceptors;however,its use and effectiveness in muscle fatigue have never been tested or explained.Possible physiological effects of subthreshold vibration in the treatment of muscle fatigue include:(1)Enhancing the function of mechanoreceptors themselves;(2)Increasing the firing rate and function of alpha motor neurons;(3)Increasing blood flow to fatigued muscles;(4)Decreasing the rate of muscle cell death in elderlies(sarcopenia);and(5)Driving motor commands and allow better performance of muscles to decrease fatigue incidence.In conclusion,the use of subthreshold vibration could be a safe and effective treatment for muscle fatigue in elderlies.It could enhance recovery from muscle fatigue.Finally,Subthreshold Vibration is safe and effective in treating muscle fatigue in comparison to suprathreshold vibration.

Insights into the adsorption performance and mechanism of Cr(Ⅵ)onto porous nanocomposite prepared from gossans and modified coal interface:Steric,energetic,and thermodynamic parameters interpretations

Herein,iron oxide/hydroxides deposits(gossans)were utilized,for the first time,in the fabrication of magnetite nanoparticles(MNPs)to load modified coal(MC).The as-synthesized MNPs@MC composite was characterized via different techniques and utilized for the Cr(Ⅵ)remediation.Experimental studies supported by theoretical treatment were applied to offer a new overview of the Cr(Ⅵ)adsorption geometry and mechanism at 25-45℃.Experimental results suggested that the Cr(Ⅵ)uptake was mainly governed by adsorption-reduction coupled mechanism.The Langmuir model fitted well the Cr(Ⅵ)adsorption data with maximum adsorption capacities extended from 115.24 to 129.63 mg·g^(-1).Theoretical calculations indicated that Cr(Ⅵ)ions were adsorbed on the MNPs@MC following the theory of the advanced monolayer statistical model.The number of ions removed per site ranged from 1.88 to1.23 suggesting the involvement of vertical geometry and multi-ionic mechanism at all temperatures.The increment of the active sites density and the adsorption capacity at saturation with improving temperature reflected an endothermic process.Energetically,the Cr(Ⅵ)adsorption was controlled by physical forces as the adsorption energies were less than 40 kJ·mol^(-1).The calculated free enthalpy,entropy.and internal energy explained the spontaneous nature and the viability of Cr(Ⅵ)adsorption on the MNPs@MC adsorbent.These results offer a new approach in utilizing the iron-rich deposits as gossans in the preparation of magnetic and low-cost adsorbents for wastewater remediation.

Implications of Onshore Development on Global Software Engineering

Recently software industry has paid significant attention to customizing software products across distributed boundaries.Communicating the requirements of multiple clients across distributed borders is a crucial challenge for the software customization process.Local decision-making and local development at the client site are considered methods for reducing difficulties in communicating the requirements of multiple clients across distributed boundaries.This paper introduces a new model called the onshore development model(ODM)for accomplishing the customization requests in the distributed development process of software.This model presents a scenario for enhancing the onsite development of specific requirements to reduce delays andmisunderstandings between the clients and the team involved.This model depends on moving the development process to the client’s location.Three empirical studies were conducted to evaluate the proposed model to measure its productivity,time performance,and cost reduction.The proposed model has been compared with two other models:the basic model(BM),which allocates the decision-making process and the development process for teams at the vendor’s location,and the local decision-making model(LDec),which assigns the decision-making process for team at the client’s location.The results of the empirical studies showed significant outperforming of the proposed model over the basic model and local decision-making model in productivity,time performance,and cost reduction.The productivity of the proposed model improved by 39%and 10%more than the basic model and the local decision-making model,respectively.In addition,the time performance of the proposed model became faster by 49%and 20.8%than the basic model and the local decision-making model,respectively.Also,it reduced the total cost of the development process by 31%in terms of the salaries of all persons involved in requirements collecting,decision-making,and development.

Efficient Technique for Image Cryptography Using Sudoku Keys

This paper proposes a cryptographic technique on images based on the Sudoku solution.Sudoku is a number puzzle,which needs applying defined protocols and filling the empty boxes with numbers.Given a small size of numbers as input,solving the sudoku puzzle yields an expanded big size of numbers,which can be used as a key for the Encryption/Decryption of images.In this way,the given small size of numbers can be stored as the prime key,which means the key is compact.A prime key clue in the sudoku puzzle always leads to only one solution,which means the key is always stable.This feature is the background for the paper,where the Sudoku puzzle output can be innovatively introduced in image cryptography.Sudoku solution is expanded to any size image using a sequence of expansion techniques that involve filling of the number matrix,Linear X-Y rotational shifting,and reverse shifting based on a standard zig-zag pattern.The crypto key for an image dictates the details of positions,where the image pixels have to be shuffled.Shuffling is made at two levels,namely pixel and sub-pixel(RGB)levels for an image,with the latter having more effective Encryption.The brought-out technique falls under the Image scrambling method with partial diffusion.Performance metrics are impressive and are given by a Histogram deviation of 0.997,a Correlation coefficient of 10−2 and an NPCR of 99.98%.Hence,it is evident that the image cryptography with the sudoku kept in place is more efficient against Plaintext and Differential attacks.

Generating of Test Data by Harmony Search Against Genetic Algorithms

Many search-based algorithms have been successfully applied in sev-eral software engineering activities.Genetic algorithms(GAs)are the most used in the scientific domains by scholars to solve software testing problems.They imi-tate the theory of natural selection and evolution.The harmony search algorithm(HSA)is one of the most recent search algorithms in the last years.It imitates the behavior of a musician tofind the best harmony.Scholars have estimated the simi-larities and the differences between genetic algorithms and the harmony search algorithm in diverse research domains.The test data generation process represents a critical task in software validation.Unfortunately,there is no work comparing the performance of genetic algorithms and the harmony search algorithm in the test data generation process.This paper studies the similarities and the differences between genetic algorithms and the harmony search algorithm based on the ability and speed offinding the required test data.The current research performs an empirical comparison of the HSA and the GAs,and then the significance of the results is estimated using the t-Test.The study investigates the efficiency of the harmony search algorithm and the genetic algorithms according to(1)the time performance,(2)the significance of the generated test data,and(3)the adequacy of the generated test data to satisfy a given testing criterion.The results showed that the harmony search algorithm is significantly faster than the genetic algo-rithms because the t-Test showed that the p-value of the time values is 0.026<α(αis the significance level=0.05 at 95%confidence level).In contrast,there is no significant difference between the two algorithms in generating the adequate test data because the t-Test showed that the p-value of thefitness values is 0.25>α.

Effect of Rituximab Versus Mycophenolate Mofetil or Cyclophosphamide as Control in Lupus Nephritis:A Meta-Analysis

Objective:To evaluate the effects of rituximab versus mycophenolate mofetil or cyclophosphamide as control in lupus nephritis by meta-analysis.Methods:A systematic search was carried out up to January 2022,obtaining 7 studies involving 645 participants with lupus nephritis at the commencement of the investigation;198 of them were treated with rituximab,while 447 were treated with mycophenolate mofetil or cyclophosphamide.We determined the odds ratio(OR)and mean difference(MD)with 95%confidence index(CI)to compare rituximab’s efficacy to that of mycophenolate mofetil or cyclophosphamide as control in lupus nephritis using random-or fixed-effects model by dichotomous or continuous techniques.Results:The rituximab group showed significantly higher complete renal remission rate(OR=2.52;95%CI 1.30-4.91,P=0.006)and total renal remission rates(OR=2.22;95%CI 1.36-3.63,P=0.001)than the control group.However,there was no significant difference in terms of end Systemic Lupus Erythematosus Disease Activity Index(SLEDAI)score(MD-1.16;95%CI-2.88-0.57,P=0.19),proteinuria(MD-0.31;95%CI-0.70-0.09,P=0.013),and serum creatinine(MD 0.01;95%CI-0.04-0.07,P=0.64)between the rituximab group and the control.Conclusion:Rituximab exhibited significantly greater complete renal remission rate and total renal remission rates,with no significant difference in terms of shorter-end SLEDAI,proteinuria,and serum creatinine,compared with the control in individuals with lupus nephritis.

Inflammatory Bowel Disease Patients’Risk of Developing Prostate Cancer:A Meta-Analysis

Background:Inflammatory bowel disease(IBD)has been linked to an increased risk of prostate cancer(PC)in numerous studies.However,the exact relationship between them remains conflicting.In this meta-analysis,we focus on determining the relationship between PC incidence and IBD.Methods:A comprehensive literature search was conducted up until January 2022,selecting 14 studies,comprising 127,323 subjects with IBD,at the beginning of the study,among which 61,985 were patients with ulcerative colitis(UC)and 37,802 were with Crohn’s disease(CD).The studies reported the differences between subjects with IBD and controls with regard to the incidence of PC.In order to investigate the relationship between IBD and the prevalence of PC,we estimated the odds ratio(OR)with 95%confidence intervals(CIs).Results:IBD significantly increased the incidence of PC(OR,3.46;95%CI,1.40-8.54,P=0.007)compared to controls.UC significantly increased the incidence of PC(OR,1.43;95%CI,1.03-1.98,P=0.03)compared to controls.Yet,no significant difference was observed between CD and controls in relation to PC incidence(OR,0.89;95%CI,0.75-1.06,P=0.18).Conclusion:IBD,particularly UC,may increase the risk of developing PC.This relationship prompts us to advocate for increased PC and IBD screening to reduce the risk for possible complications that could occur in these subjects.

A Meta-Analysis of the Effectiveness of Vitamin C in the Prevention and Treatment of Childhood Upper Respiratory Tract Infections

Background:The effectiveness of vitamin C in the prevention and treatment of pediatric upper respiratory tract infections was evaluated in a meta-analysis.Methods:A total 2,573 children with upper respiratory tract infections were included in the meta-analysis,1,280 of whom received vitamin C and 1,293 who received control medication.The analysis of findings related to the studies included was done through random or fixed effects model to determine whether vitamin C supplementation could stop and control upper respiratory tract infections in children using mean difference(MD)with 95%confidence intervals(CIs).Results:On average,vitamin C-treated children had fewer upper respiratory tract infection bouts,their illness lasted shorter(MD-0.84;95%CI-1.47 to-0.20,P=0.009),and they were less contagious than the control.Conclusions:The number of episodes and illness duration of upper respiratory tract-infected pediatric subjects were considerably reduced in the intervention group(vitamin C)compared to the control.Due to the small sample size in four of 11 studies and the limited number of studies included for comparison,the outcomes should be carefully examined.

Sequence Stratigraphy and Rudist Facies Development of the Upper Barremian-Lower Cenomanian Platform, Northern Sinai, Egypt

The Lower Cretaceous sections in northern Sinai are composed of the Risan Aneiza （upper Barremian-middle Albian） and the Halal （middle Albian-lower Cenomanian） formations. The facies reflect subtle paleobathymetry from inner to outer ramp facies. The inner ramp facies are peritidal, protected to open marine lagoons, shoals and rudist biostrome facies. The inner ramp facies grade northward into outer ramp deposits. The upper Barremian-lower Cenomanian succession is subdivided into nine depositional sequences correlated with those recognized in the neighbouring Tethyan areas. These sequences are subdivided into 19 medium-scale sequences based on the facies evolution, the recorded hardgrounds and flooding surfaces, interpreted as the result of eustatic sea level changes and local tectonic activities of the early Syrian Arc rifting stage. Each sequence contains a lower retrogradational parasequence set that constituted the transgressive systems tracts and an upper progradational parasequence set that formed the highstand systems tracts. Nine rudist levels are recorded in the upper Barremian through lower Cenomanian succession at Gabal Raghawi. At Gabal Yelleg two rudist levels are found in the Albian. The rudist levels are associated with the highstand systems tract deposits because of the suitability of the trophic conditions in the rudist-dominated ramp.

Purslane protects against the reproductive toxicity of carbamazepine treatment in pilocarpine-induced epilepsy model

Objective: To investigate the protective effect of purslane with carbamazepine treatment.Methods: Male albino rats were modulated by pilocarpine to be epileptic.Both the normal and epileptic rats were treated with carbamazepine, purslane or carbamazepine plus purslane, with separate non-treated control groups for both normal and epileptic rats.Results: The data from the current study showed amelioration in amino acids and electrolytes in the epileptic rats treated with purslane and carbamazepine, with this amelioration occurring without decreasing the fertility hormones(testosterone,dehydroepiandrosterone, luteinizing hormone and follicle stimulating hormone).Purslane treatments also prevented the increase in estradiol.The decreased epileptic hyperexcitability with purslane was evidenced by decreased glial fibrillary acidic protein and lipid peroxidation.Conclusions: Natural products like purslane could be used with the highly repetitive drugs like carbamazepine to reduce or prevent its side-effects.

Validated stability indicating methods for determination of nitazoxanide in presence of its degradation products

Three sensitive,selective and reproducible stability-indicating methods are presented for determination of nitazoxanide (NTZ),a new anti-protozoal drug,in presence of its degradation products.Method A utilizes the first derivative of ratio spectra spectrophotometry by measurement of the amplitude at 364.4 nm using one of the degradation products as a divisor.Method B is a chemometric-assisted spectrophotometry,where principal component regression (PCR) and partial least squares (PLS) were applied.These two approaches were successfully applied to quantify NTZ in presence of degradation products using the information included in the absorption spectra in the range 260-360 nm.Method C is based on the separation of NTZ from its degradation products followed by densitometric measurement of the bands at 254 nm.The separation was carried out on silica gel 60F 254,using chloroform-methanol-ammonia solution-glacial acetic acid (95:5:1:1 by volume,pH=5.80) as a developing system.These methods are suitable as stability-indicating methods for the determination of NTZ in presence of its degradation products either in bulk powder or in pharmaceutical formulations.Statistical analysis of the results has been carried out revealing high accuracy and good precision.

Influence of temperature on the properties of one-dimensional piezoelectric phononic crystals

The current study investigates the influence of temperature on a one-dimensional piezoelectric phononic crystal using tunable resonant frequencies. Analytical and numerical examples are introduced to emphasize the influence of temperature on the piezoelectric phononic crystals. It was observed that the transmission spectrum of a one-dimensional phononic crystal containing a piezoelectric material（0.7 PMN-0.3 PT） can be changed drastically by an increase in temperature.The resonant peak can be shifted toward high or low frequencies by an increase or decrease in temperature, respectively.Therefore, we deduced that temperature can exhibit a large tuning in the phononic band gaps and in the local resonant frequencies depending on the presence of a piezoelectric material. Such result can enhance the harvesting energy from piezoelectric materials, especially those that are confined in a phononic crystal.

铁对粉末冶金法制备铝基复合材料微观组织和力学性能及磁学性能的影响(英文)

研究铁对粉末冶金法制备铝基复合材料微观组织、力学性能及磁学性能的影响。利用机械混合制备含0,5%,10%和15%Fe(质量分数)的铝基复合材料。Al-Fe混合粉末经压制后在真空炉中600°C烧结1 h。XRD结果表明:在含有5%和10%Fe的试样中只有Fe和Al的衍射峰,而含有15%Fe的试样中则存在Al和Al13Fe4的衍射峰。实验结果表明:随着Fe含量的增加,材料的致密度和导热性变差。复合材料中的Fe可以提高其强度和硬度。材料的强化机制包括基体的晶粒细化,Fe颗粒的均匀分布以及Al13Fe4金属间化合物的形成。含有5%Fe试样的磁化强度为0.3816×10-3A·m2/g,对于含有10%Fe的试样,其磁化强度增加至0.6597×10-3A·m2/g,而对于含有15%Fe试样,其磁化强度降低至0.0702×10-3A·m2/g。这是由于在高铁试样中形成了反磁性的Al13Fe4金属间化合物导致磁化强度降低。

Improve the Efficiency of Scintillation Detectors Using Reflectors Based on Photonic Crystals Arrays

In the present work, we designed the new type of photonic crystals (PCs) as reflectors. Reflections from single layer of Al2O3/MgO PC help us in recapturing the light that does escape from the scintillation surface. Photonic crystals in one dimension array of Al2O3 and MgO with silver at periodicities N = 1, 2 and 3 were used as a reflector around the surface of the scintillation volume. Scintillation detectors are widely used in nuclear medicine. The efficiency is an important parameter for characterizing the capability of the detectors. The counting efficiency of the detectors depends on the light emission induced by radiation. The light then was converted by the photomultiplier tube into electrical pulses. The efficiency may increase by an amount of 1.64% if MgO-Ag photonic crystals are used at periodicity N = 1 as a reflector.

Genotyping and pathotyping of diversified strains of infectious bronchitis viruses circulating in Egypt

AIM: To characterize the circulating infectious bronchitis virus(IBV) strains in Egypt depending on the sequence of the spike-1(S1) gene [hypervariable region-3(HVR-3)] and to study the pathotypic features of these strains.METHODS: In this work, twenty flocks were sampled for IBV detection using RRT-PCR and isolation of IBV in specific pathogen free(SPF) chicks during the period from 2010 to 2015. Partial sequencing and phylogenetic analysis of 400 bp representing the HVR-3 of the S1 gene was conducted. Pathotypic characterization of one selected virus from each group(Egy/Var-Ⅰ, Egy/Var-Ⅱ and classic) was evaluated in one day old SPF chicks. The chicks were divided into 4 groups 10 birds each including the negative control group. Birds were inoculated at one day by intranasal instillation of 105EID50/100 μL of IBV viruses [IBV-EG/1212B-2012(Egy/Var-Ⅱ), IBV/EG/IBV1-2011(Egy/Var-Ⅰ) and IBV-EG/11539F-2011(classic)], while the remaining negative control group was kept uninfected. The birds were observed for clinical signs, gross lesions and virus pathogenicity. The real-time rR TPCR test was performed for virus detection in the tissues. Histopathological examinations were evaluated in both trachea and kidneys.RESULTS: The results revealed that these viruses were separated into two distinct groups; variant(GI-23) and classic(GI-1), where 16 viruses belonged to a variant group, including 2 subdivisions [Egy/Var-Ⅰ(6 isolates) and Egy/Var-Ⅱ(10 isolates)] and 4 viruses clustered to the classic group(Mass-like). IBV isolates in the variant group were grouped with other IBV strains from the Middle East. The variant subgroup(Egy/Var-Ⅰ) was likely resembling the original Egyptian variant strain(Egypt/Beni-Suif/01) and the Israeli strain(IS/1494/2006). The second subgroup(Egy/Var-Ⅱ) included the viruses circulating in the Middle East(Ck/EG/BSU-2 and Ck/EG/BSU-3/2011) and the Israeli strain(IS/885/00). The two variant subgroups(Egy/Var-Ⅰ and Egy/Var-Ⅱ) found to be highly pathogenic to SPF chicks with mortalities up to 50% than those of the classic group which was of low virulence(10% mortality). Pathogenicity indices were 25(Egy/Var-Ⅱ), 24(Egy/Var-Ⅰ) and 8(classic); with clinical scores 3, 2 and 1 respectively.CONCLUSION: These findings indicated that the recent circulating Egyptian IBVs have multiple heterogeneous origins in marked diversifying nature of their spread, with high pathotype in specific pathogen free chicks.

FINITE GROUPS WHOSE MINIMAL SUBGROUPS ARE WEAKLY H-SUBGROUPS

Let G be a finite group. A subgroup H of G is called an H-subgroup in G if NG（H）∩ H^g ≤ H for all g C G. A subgroup H of G is called a weakly H-subgroup in G if there exists a normal subgroup K of G such that G = HK and H N K is an H-subgroup in G. In this paper, we investigate the structure of the finite group G under the assumption that every subgroup of G of prime order or of order 4 is a weakly H-subgroup in G. Our results improve and generalize several recent results in the literature.

Developmental competence of bovine oocytes with increasing concentrations of nano-copper and nano-zinc particles during in vitro maturation

Objective: To evaluate copper and zinc concentrations in plasma and follicular fluid from cattle ovaries, and estimate the impact of rational concentrations of copper and zinc oxide nanoparticles (CuO-NPs & ZnO-NPs) supplemented during in vitro maturation (IVM) against DNA damage of cumulus cells, glutathione content in oocytes and on consequent embryo development. Methods: Oocytes were obtained from 2 to 8 mm follicles by aspiration method for IVM. Replicates of experiments were performed on different days, with a separate batch of cumulus oocytes complex for each day. Results: The DNA damage of oocytes and cumulus cells significantly decreased with supplemental CuO-NPs or ZnO-NPs concentrations of 0.7 and 1.0 μg/mL in the IVM medium compared to medium without CuO-NPs or ZnO-NPs (P < 0.01). Total glutathione concentrations in oocytes and cumulus cells significantly increased following supplementation with both 0.7 and 1.0 μg/mL CuO-NPs or ZnO-NPs in comparison with 0 and 0.4 μg/mL CuO-NPs or ZnO-NPs supplemented groups (P < 0.01). Supplementation of CuO-NPs or ZnO-NPs during IVM medium at any concentration had no significant effect on cleavge rate. Both CuO-NPs and ZnO-NPs significantly increased blastocyst rates when oocytes were matured with 0.7, 1.0 μg/mL CuO-NPs concentrations (P < 0.01). In contrast, addition of 1.5 μg/mL of CuO-NPs or ZnO-NPs to the maturation media resulted in detrimental effects on the developmental competence of bovine oocytes confirming toxicity induced by CuO-NPs and ZnO-NPs in high concentrations. Conclusions: CuO-NPs or ZnO-NPs-treated bovine oocytes during IVM show low level of DNA fragmentation and increased intracellular glutathione content of cumulus cells. In vitro embryo development is improved by supplementation of rational concentrations of CuO-NPs or ZnO-NPs to culture media. Toxicity induced by CuO-NPs and ZnO-NPs is confirmed in high concentrations.

酶法提高黏性土回弹模量（英文）

本研究利用回弹模量来评价酶法制备稳定黏性土的动力响应。根据AASHTO T307标准,对三种经过酶制剂处理的黏性土进行了回弹模量测试,以探讨其在道路建设中的作用。结果表明,与未经过处理的土样相比,经过酶制剂处理的土样回弹模量明显提高,为原来的1.4~4.4倍。由于回弹模量测试的复杂性,进行了回归分析,建立了可靠的相关公式,预测了应力状态下未经处理的和稳定的土样的回弹模量。采用通用模型确定了路基材料在预期场强下的回弹模量。将酶法制备方法应用于样本路段,并通过平板载荷试验对其进行评价。土样的扫描电镜结果分析表明,减小土壤颗粒间的空隙可以改善土样的压实效果。XRD分析结果表明,处理后的土壤结构无明显变化。酶制剂含有43 mg/mL的蛋白质,采用SDS-PAGE(十二烷基硫酸钠聚丙烯酰胺凝胶电泳)技术鉴定主要的蛋白质组分,但干扰物质(表面活性剂)阻碍了分离作用。