Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo development.In some mammals,like pigs,ejaculates are emitted in three separa...Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo development.In some mammals,like pigs,ejaculates are emitted in three separate fractions:pre-sperm,sperm-rich(SRF)and post sperm-rich(PSRF).These fractions are known to vary in volume,sperm concentration and quality,as well as in the origin and composition of seminal plasma(SP),with differences being also observed within the SRF one.Yet,whether disparities in the DNA integrity and chromatin condensation and pro-tamination of their sperm exist has not been interrogated.Results This study determined chromatin protamination(Chromomycin A3 test,CMA_(3)),condensation(Dibromobi-mane test,DBB),and DNA integrity(Comet assay)in the pig sperm contained in the first 10 m L of the SRF(SRF-P1),the remaining portion of the sperm-rich fraction(SRF-P2),and the post sperm-rich fraction(PSRF).While chromatin protamination was found to be similar between the different ejaculate fractions(P>0.05),chromatin condensation was seen to be greater in SRF-P1 and SRF-P2 than in the PSRF(P=0.018 and P=0.004,respectively).Regarding DNA integrity,no differences between fractions were observed(P>0.05).As the SRF-P1 has the highest sperm concentra-tion and ejaculate fractions are known to differ in antioxidant composition,the oxidative stress index(OSi)in SP,calcu-lated as total oxidant activity divided by total antioxidant capacity,was tested and confirmed to be higher in the SRF-P1 than in SRF-P2 and PSRF(0.42±0.06 vs.0.23±0.09 and 0.08±0.00,respectively;P<0.01);this index,in addition,was observed to be correlated to the sperm concentration of each fraction(Rs=0.973;P<0.001).Conclusion While sperm DNA integrity was not found to differ between ejaculate fractions,SRF-P1 and SRF-P2 were observed to exhibit greater chromatin condensation than the PSRF.This could be related to the OSi of each fraction.展开更多
Purpose–The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system.This paper aims to define and substantiate the ass...Purpose–The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system.This paper aims to define and substantiate the assessment of the structural integrity and dynamical integrity of high-speed trains in both theory and practice.The key principles and approacheswill be proposed,and their applications to high-speed trains in Chinawill be presented.Design/methodology/approach–First,the structural integrity and dynamical integrity of high-speed trains are defined,and their relationship is introduced.Then,the principles for assessing the structural integrity of structural and dynamical components are presented and practical examples of gearboxes and dampers are provided.Finally,the principles and approaches for assessing the dynamical integrity of highspeed trains are presented and a novel operational assessment method is further presented.Findings–Vehicle system dynamics is the core of the proposed framework that provides the loads and vibrations on train components and the dynamic performance of the entire vehicle system.For assessing the structural integrity of structural components,an open-loop analysis considering both normal and abnormal vehicle conditions is needed.For assessing the structural integrity of dynamical components,a closed-loop analysis involving the influence of wear and degradation on vehicle system dynamics is needed.The analysis of vehicle system dynamics should follow the principles of complete objects,conditions and indices.Numerical,experimental and operational approaches should be combined to achieve effective assessments.Originality/value–The practical applications demonstrate that assessing the structural integrity and dynamical integrity of high-speed trains can support better control of critical defects,better lifespan management of train components and better maintenance decision-making for high-speed trains.展开更多
This study is concerned with the surface integrity of Inconel 738LC parts manufactured by selective laser melting(SLM)followed by high-speed milling(HSM).In the investigation process of surface integrity,the study emp...This study is concerned with the surface integrity of Inconel 738LC parts manufactured by selective laser melting(SLM)followed by high-speed milling(HSM).In the investigation process of surface integrity,the study employs ultradepth three-dimensional microscopy,laser scanning confocal microscopy,scanning electron microscopy,electron backscatter diffractometry,and energy dispersive spectroscopy to characterize the evolution of material microstructure,work hardening,residual stress coupling,and anisotropic effect of the building direction on surface integrity of the samples.The results show that SLM/HSM hybrid manufacturing can be an effective method to obtain better surface quality with a thinner machining metamorphic layer.High-speed machining is adopted to reduce cutting force and suppress machining heat,which is an effective way to produce better surface mechanical properties during the SLM/HSM hybrid manufacturing process.In general,high-speed milling of the SLM-built Inconel 738LC samples offers better surface integrity,compared to simplex additive manufacturing or casting.展开更多
Generally,the so-called expansion agent is very effective in eliminating all the micro-annuli that exist between the casing and the cement sheath or between the cement sheath and the formation.However,this approach ca...Generally,the so-called expansion agent is very effective in eliminating all the micro-annuli that exist between the casing and the cement sheath or between the cement sheath and the formation.However,this approach can detrimentally affect the sealing ability of cement sheath if the expansion agent is used in an unreasonable way.For these reasons,in the present work,numerical simulations have been conducted to analyze the effect of elasticity modulus of cement sheath,the elasticity modulus of formation,the expansion rate of cement,the geo-stress on the micro-annulus caused by cement expansion,and the cement sheath expansion on the integrity of cement sheath and formation.The micro-annulus between the casing and the cement sheath has been found to decrease according to the ratio between the elasticity modulus of formation and the elasticity modulus of cement sheath.A positive correlation has been observed between the micro-annulus and the cement expansion ratio.The microannulus decreases as the geo-stress increases,but the effect of the geo-stress on the micro-annulus is much smaller.In conclusion,the expansion agent is suitable for the formation in which the elasticity modulus is higher than the cement sheath.展开更多
Aiming at the issue of the grinding integrity of face-gear with worm wheel, the envelope mathematical model of shaper, worm wheel and face-gear is established based on theories of differential geometry and gear mesh. ...Aiming at the issue of the grinding integrity of face-gear with worm wheel, the envelope mathematical model of shaper, worm wheel and face-gear is established based on theories of differential geometry and gear mesh. The judgment of completely grinding the face-gear with the avoidance of singularities is established, and the mathematical expression to show the reason why singularities appear is derived, through the research on the surface contact area and singularity rules of the worm thread surface. The disadvantage of current face-gear grinding method that only part of the working surface of the face-gear can be covered is analyzed and the influence of coefficient of judgment is studied through changing the design parameters.展开更多
To evaluate the new designed cutting tools for high-efficiency milling of the hardened die steel SKD11,surface integrities of millers with different geometric structures are analyzed, considering the surface roughness...To evaluate the new designed cutting tools for high-efficiency milling of the hardened die steel SKD11,surface integrities of millers with different geometric structures are analyzed, considering the surface roughness, micrograph of chips, surface microhardness, residual stress and metallurgical texture of the surface layer. The in fluences of geometric characteristics of different cutting tools and their wear characteristics on the surface integrity are studied. Results show that the milling tool with rake angle; 5 of the hardened diesteel. The generation of saw-tooth chips is depressed when a reasonable positive rake angle is selected. And the compressive residual stress is induced on the machined surface in milling the hardened die steel. The occurrence of surface softening is postponed by increasing the clearance angle and reducing the tool flank wear.展开更多
An experimental study was carried out to investigat e the influence of temperatures on workpiece surface integrity in surface grinding of a cast nickel-based superalloy with alumina abrasive wheels. Temperatur e respo...An experimental study was carried out to investigat e the influence of temperatures on workpiece surface integrity in surface grinding of a cast nickel-based superalloy with alumina abrasive wheels. Temperatur e response at the wheel-workpiece interface was measured using a grindable foil /workpiece thermocouple. Specimens with different grinding temperatures were obt ained through changing grinding conditions including depth of cut, workpiece fee d speed, and coolant supply. Changes in surface roughness, residual stress, meta llographies, ground surface morphology, and micro hardness on the specimens were then analyzed. Bending fatigue tests were separately conducted at room temperat ure and 950oC in an effort to evaluate the influence of temperatures on the serv ice life of the ground specimens. A different burning color was found on the gro und workpiece surfaces when grinding temperatures are over a critical value. Alo ng with the emergence of burning color, roughness of the ground workpiece surfac e increased greatly compared with the surfaces without burning color, which was attributed to the plastically deformed coatings on the workpiece surface with el evated temperatures. Excepting the surface roughness, other items concerning the surface integrity of the ground workpiece were not affected by temperatures pro vided that grinding temperatures are not high enough to cause grinding cracks. B ased on the findings in this study, the grinding of the nickel-based superalloy can be divided into two stages in order to increase production efficiency, in which case the first stage is to reach an high material removal rate without concerning of the presence of burning color, whereas the second stage is to remo ve the plastically deformed coatings in order to decrease surface roughness.展开更多
The principle and process of parallel seismic (PS) testing for the integrity testing of cemented soil columns are in- troduced in this paper. A three-dimensional (3D) finite element model (FEM) for the pile-soil syste...The principle and process of parallel seismic (PS) testing for the integrity testing of cemented soil columns are in- troduced in this paper. A three-dimensional (3D) finite element model (FEM) for the pile-soil system is established for impulse responses. Under saturated soil or unsaturated soil condition, several vibrating velocity-time histories at different depths in parallel hole are obtained based on the numerical simulation. It shows that the length of the pile and the one-dimensional (1D) P-wave velocity in the pile can be determined easily from the features of the mentioned velocity-time histories. By examining the slopes of the first arrival time plotted versus depth or the depth where the amplitude of the first arrival significantly decreases, the length of the pile can be determined. The effects of the 3D P-wave propagation through the saturated soil and the defect of the cemented soil column on the velocity-time histories are also investigated.展开更多
The Ti6Al4V parts produced by the existing selective laser melting(SLM)are mainly confronted with poor surface finish and inevitable interior defects,which substantially deteriorates the mechanical properties and perf...The Ti6Al4V parts produced by the existing selective laser melting(SLM)are mainly confronted with poor surface finish and inevitable interior defects,which substantially deteriorates the mechanical properties and performances of the parts.In this regard,ultrasonically-assisted machining(UAM)technique is commonly introduced to improve the machining quality due to its merits in increasing tool life and reducing cutting force.However,most of the previous studies focus on the performance of UAM with ultrasonic vibrations applied in the tangential and feed directions,whereas few of them on the impact of ultrasonic vibration along the vertical direction.In this study,the effects of feed rate on surface integrity in ultrasonically-assisted vertical milling(UAVM)of the Ti6Al4V alloy manufactured by SLM were systemically investigated compared with the conventional machining(CM)method.The results revealed that the milling forces in UAVM showed a lower amplitude than that in CM due to the intermittent cutting style.The surface roughness values of the parts produced by UAVM were generally greater than that by CM owing to the extra sinusoidal vibration textures induced by the milling cutter.Moreover,the extra vertical ultrasonic vibration in UAVM was beneficial to suppressing machining chatter.As feed rate increased,surface microhardness and thickness of the plastic deformation zone in CM raised due to more intensive plastic deformation,while these two material properties in UAVM were reduced owing to the mitigated impact effect by the high-frequency vibration of the milling cutter.Therefore,the improved surface microhardness and reduced thickness of the subsurface deformation layer in UAVM were ascribed to the vertical high-frequency impact of the milling cutter in UAVM.In general,the results of this study provided an in-depth understanding in UAVM of Ti6Al4V parts manufactured by SLM.展开更多
Objective To determine the membrane integrity in the head and tail regions of individual spermatozoon, and observe sperm morphology for samples with totally immotile sperm. Methods Ten infertile men with immotile sper...Objective To determine the membrane integrity in the head and tail regions of individual spermatozoon, and observe sperm morphology for samples with totally immotile sperm. Methods Ten infertile men with immotile sperm were enrolled into this study (group A). The membrane integrity in the head and tail regions of individual spermatozoon of immotile sperm was examined by using the combined hypo-osmotic swelling-eosin Y exclusion test (HOS-EY test). Sperm morphology was observed by light, scanning and transmission electron microscopy. Ten semen samples from normospermic donors were used as the control (group B). Results The percentage of sperm with intact both head and tail membranes in group A was significantly lower than that in group B (P〈0.01), whereas the value of sperm with defective head membrane but intact tail membrane in group A was significantly higher than that in group B (P〈0.01). Abnormal sperm morphology in group A had a high incidence, and immotile sperm with viability and normal morphology could be observed in some cases. Most sperm had multiple ultrastructural defects. Conclussion Some immotile sperm had intact tail membrane but defective head membrane. Immotile sperm with viability and normal morphology could exist in some cases though abnormal sperm were in a great proportion. Carefully evaluating immotile sperm membrane integrity and morphology should benefit the treatment of patients with immotile sperm.展开更多
Cloud computing and storage services allow clients to move their data center and applications to centralized large data centers and thus avoid the burden of local data storage and maintenance.However,this poses new ch...Cloud computing and storage services allow clients to move their data center and applications to centralized large data centers and thus avoid the burden of local data storage and maintenance.However,this poses new challenges related to creating secure and reliable data storage over unreliable service providers.In this study,we address the problem of ensuring the integrity of data storage in cloud computing.In particular,we consider methods for reducing the burden of generating a constant amount of metadata at the client side.By exploiting some good attributes of the bilinear group,we can devise a simple and efficient audit service for public verification of untrusted and outsourced storage,which can be important for achieving widespread deployment of cloud computing.Whereas many prior studies on ensuring remote data integrity did not consider the burden of generating verification metadata at the client side,the objective of this study is to resolve this issue.Moreover,our scheme also supports data dynamics and public verifiability.Extensive security and performance analysis shows that the proposed scheme is highly efficient and provably secure.展开更多
A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,e...A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,energy dissipation,and habitat.These small units may be fabricated in standard block machines.In coastal applications,A-Jacks are used in breakwaters,jetties,revetments,and habitat development.Coastal units are generally much larger and more robust than the small open channel units.This paper focuses on coastal applications and in particular,combines results on three topics:(1)recent hydraulic model studies,(2)alternative fabrication methods,and(3)bundle placement construction methods.Hydraulic models studies were conducted that examined the standard random and uniform placement methods,and also the bundle placement method.In bundle placement,3~20 A-Jacks are banded together,lifted with a spreader bar,and placed as a single crane pick.This significantly decreases installation time during construction.It also provides a more hydraulically stable placement technique.The hydraulic model tests examined the bundle stability in random waves for cases where the binding remains in tack and is removed.The geometry of A-Jacks enables a variety of fabrication techniques.One option is to fabricate the A-Jacks as two pieces using flat forms and then grout the two pieces together.Flat forms may be used in conventional block machines for A-Jacks sizes up to 1.3 m.Larger sizes may be wet cast in flat forms or gang forms.The A-Jacks geometry has been recently modified to increase grouting efficient and strength.Large A- Jacks may also be cast in a single piece using 'clam shell' type forms.展开更多
Ten years after the initial generation of induced pluripotent stem cells(hiPSCs)from human tissues,their potential is no longer questioned,with over 15000 publications listed on PubMed,covering various fields of resea...Ten years after the initial generation of induced pluripotent stem cells(hiPSCs)from human tissues,their potential is no longer questioned,with over 15000 publications listed on PubMed,covering various fields of research;including disease modeling,cell therapy strategies,pharmacology/toxicology screening and 3D organoid systems.However,despite evidences that the presence of mutations in hiPSCs should be a concern,publications addressing genomic integrity of these cells represent less than 1%of the literature.After a first overview of the mutation types currently reported in hiPSCs,including karyotype abnormalities,copy number variations,single point mutation as well as uniparental disomy,this review will discuss the impact of reprogramming parameters such as starting cell type and reprogramming method on the maintenance of the cellular genomic integrity.Then,a specific focus will be placed on culture conditions and subsequent differentiation protocols and how their may also trigger genomic aberrations within the cell population of interest.Finally,in a last section,the impact of genomic alterations on the possible usages of hiPSCs and their derivatives will also be exemplified and discussed.We will also discuss which techniques or combination of techniques should be used to screen for genomic abnormalities with a particular focus on the necessary quality controls and the potential alternatives.展开更多
In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simu...In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the thermal distribution at the brazed joint zone is related to not only the geometry of the fin and tube, butalso the brazed joint topology. A poor brazed joint will result in very poor heat transfer. Thermal contact resistanceis adopted to analyze the fin heat efficiency.展开更多
Unauthorized tampering with outsourced data can result in significant losses for both data owner and users.Data integrity therefore becomes an important factor in outsourced data systems.In this paper,we address this ...Unauthorized tampering with outsourced data can result in significant losses for both data owner and users.Data integrity therefore becomes an important factor in outsourced data systems.In this paper,we address this problem and propose a scheme for verifying the integrity of outsourced data.We first propose a new authenticated data structure for authenticating membership queries in sets based on accumulators,and then show how to apply it to the problem of verifying the integrity of outsourced data.We also prove that our scheme is secure under the q-strong DiffieHellman assumption.More importantly,our scheme has the constant cost communication,meanwhile keeping other complexity measures constant.Compared to previous schemes based on accumulators,our scheme reduces update cost and so improves previous schemes based on accumulators.In addition,the experimental comparison shows that our scheme outperforms the previous schemes.展开更多
The seeds of a soybean cultivar Zhonghuang 18 were subjected to accelerated aging for 0(population G_0-1), 112(population G_0-2), 154(population G_0-3) and 196 d(population G_0-4), whose germination percentage was fou...The seeds of a soybean cultivar Zhonghuang 18 were subjected to accelerated aging for 0(population G_0-1), 112(population G_0-2), 154(population G_0-3) and 196 d(population G_0-4), whose germination percentage was found to be 98.0%, 95.0%, 81.0%, and 79.0%, respectively. Then, the four populations were regenerated twice in the field. The first descendant populations were marked as G_1-1, G_1-2, G_1-3 and G_1-4, and the second were marked as G_2-1, G_2-2, G_2-3 and G_2-4, respectively. The genetic variation between the control population(G_0-1) and the experimental populations was analyzed using 12 AFLP primer combinations. The results showed that there was no significant difference in genetic similarity between the 11 experimental populations and the control population G_0-1. The genetic similarity between population G_2-4 and G_0-1 was still as high as 0.933 3, indicating that the F_2 generation of the population whose germination percentage was only 79.0% still had a high genetic similarity to the control population. The results of t-tests revealed that the populations G_1-1, G_2-1, G_1-2 and G_2-2 showed no significant difference from the control population G_0-1 in effective number of alleles per locus(Ae), genetic diversity index(H) and Shannon's diversity index(I), while these indices of populations G_0-3, G_0-4, G_1-3, G_1-4, G_2-3 and G_2-4 were significantly reduced. χ~2 tests indicated that the populations G_1-1 and G_2-1 showed little difference, and the populations G_0-2, G_0-3, G_0-4, G_1-2, G_1-3, G_1-4, G_2-2, G_2-3, and G_2-4 showed great difference in allele frequency distribution from the control population G_0-1, and the difference was greater when the seed viability was lower. Compared with the control population G_0-1, the number of rare alleles(Nr) of the populations G_0-2, G_1-1, G_2-1, G_1-2 and G_2-2 showed no significant difference, while that of the populations G_0-3, G_0-4, G_1-3, G_1-4, G_2-3 and G_2-4 declined obviously. These results revealed that compared with the control population, the genetic diversity and Nr for the descendant populations of the populations with 98.0% and 95.0% germination percentages did not change significantly, but declined greatly for the descendant populations of the populations with 81.0.% and 79.0% percentages. The results suggested that the decline in seed viability has a greater impact than the number of generations on genetic structure of soybean germplasm. So, it is suggested that soybean seed with an initial germination percentage of 98.0% should be regenerated before its germination percentage declines to 81.0%.展开更多
One of the major problems associated with the therapeutic application of β-lactam antibiotics is their significant instability [1]-[3]. Analogs from that group are easily degraded in aqueous solutions and in solid st...One of the major problems associated with the therapeutic application of β-lactam antibiotics is their significant instability [1]-[3]. Analogs from that group are easily degraded in aqueous solutions and in solid state, which happens predominantly as a result of β-lactam ring chemical degradation. Because of this, the chemical integrity of β-lactam antibiotics must be closely monitored to meet FDA requirements. The original iodometric method based on visual detection of the end products of beta-lactamase hydrolysis that has been used to test beta-lactamase activity [4] was modified to quantitatively assess the amount of degraded product in amoxicillin. A UV-visible spectrophotometric method has been used, focusing on the ability of the products from the degradation of β-lactam analogs to absorb iodine from bulk solution, resulting in a significant reduction in the absorption spectra. Amoxicillin trihydrate tablets with different expiration dates and amoxicillin samples pre-loaded with known amounts of degraded amoxicillin have been used to generate a calibration curve and quantify the presence of degraded materials. Results show that the changes in the absorption spectra of iodine reagent directly correlate with the fraction of degraded β-lactam antibiotics, such as amoxicillin, in commercial products. The proposed assay might be as close as one step from simpler and cheaper methods of quantitative analysis of degraded β-lactam analogs, with estimated sensitivity in the range of 1% - 2%, which is better than the current FDA requirements.展开更多
The domination integrity of a connected graph G= (V(G), E(G)) is denoted as DI(G) and defined by DI(G) = min{*S*+ m(G-S) : S is a dominating set } where m(G-S) is the order of a maximum component of G-S . We discuss d...The domination integrity of a connected graph G= (V(G), E(G)) is denoted as DI(G) and defined by DI(G) = min{*S*+ m(G-S) : S is a dominating set } where m(G-S) is the order of a maximum component of G-S . We discuss domination integrity in the context of some graph operations like duplication of an edge by vertex and duplication of vertex by an edge.展开更多
Rare earth elements have been extensively used as micro-fertilizers for crops in China. To?understand the potential benefits or damages of Ce4+ on rice, the effects of Ce4+ on viability and membrane integrity of rice ...Rare earth elements have been extensively used as micro-fertilizers for crops in China. To?understand the potential benefits or damages of Ce4+ on rice, the effects of Ce4+ on viability and membrane integrity of rice were investigated under hydroponic cultures. It has been found that the cell viability, electrical conductivity, pH changes, and concentration of malonyl dialdehyde did not change obviously when the content of Ce4+ was 0.5 mg/L, but varied markedly when the contents of Ce4+ were raised to 10 mg/L or more, indicating that the Ce4+ at higher concentrations severely affected the cell membrane permeability.展开更多
In an addition to the variety of topics in aims and scope of the Journal of International Relations and Diplomacy, we would be happy to offer here some more areas in line with its general orientation, which could be w...In an addition to the variety of topics in aims and scope of the Journal of International Relations and Diplomacy, we would be happy to offer here some more areas in line with its general orientation, which could be worth investigating, encouraging more paper submissions. These relate to effective organization of large distributed dynamic systems of diverse natures which may require innovative solutions reflecting the growing world dynamics in the 21 st century with emerging challenges and threats to local and global prosperity, stability, and safety.展开更多
基金This research was supported by the European Union’s Horizon 2020 research and innovation scheme under the Marie Skłodowska-Curie grant agreement No.801342(Tecniospring INDUSTRYGrant:TECSPR-19-1-0003)+4 种基金the Ministry of Science and Innovation,Spain(Grants:PID2020-113320RB-I00,PID2020-113493RB-I00,RYC2021-034546-I and RYC2021-034764-I)the Catalan Agency for Management of University and Research Grants,Regional Government of Catalonia,Spain(Grants:2017-SGR-1229 and 2021-SGR-00900)the Seneca Foundation,Regional Government of Murcia,Spain(Grant:21935/PI/22)La Marato de TV3 Foundation(Grant:214/857-202039)and the Catalan Institution for Research and Advanced Studies(ICREA).
文摘Background Protamination and condensation of sperm chromatin as well as DNA integrity play an essential role during fertilization and embryo development.In some mammals,like pigs,ejaculates are emitted in three separate fractions:pre-sperm,sperm-rich(SRF)and post sperm-rich(PSRF).These fractions are known to vary in volume,sperm concentration and quality,as well as in the origin and composition of seminal plasma(SP),with differences being also observed within the SRF one.Yet,whether disparities in the DNA integrity and chromatin condensation and pro-tamination of their sperm exist has not been interrogated.Results This study determined chromatin protamination(Chromomycin A3 test,CMA_(3)),condensation(Dibromobi-mane test,DBB),and DNA integrity(Comet assay)in the pig sperm contained in the first 10 m L of the SRF(SRF-P1),the remaining portion of the sperm-rich fraction(SRF-P2),and the post sperm-rich fraction(PSRF).While chromatin protamination was found to be similar between the different ejaculate fractions(P>0.05),chromatin condensation was seen to be greater in SRF-P1 and SRF-P2 than in the PSRF(P=0.018 and P=0.004,respectively).Regarding DNA integrity,no differences between fractions were observed(P>0.05).As the SRF-P1 has the highest sperm concentra-tion and ejaculate fractions are known to differ in antioxidant composition,the oxidative stress index(OSi)in SP,calcu-lated as total oxidant activity divided by total antioxidant capacity,was tested and confirmed to be higher in the SRF-P1 than in SRF-P2 and PSRF(0.42±0.06 vs.0.23±0.09 and 0.08±0.00,respectively;P<0.01);this index,in addition,was observed to be correlated to the sperm concentration of each fraction(Rs=0.973;P<0.001).Conclusion While sperm DNA integrity was not found to differ between ejaculate fractions,SRF-P1 and SRF-P2 were observed to exhibit greater chromatin condensation than the PSRF.This could be related to the OSi of each fraction.
基金This work was partly funded by the National Key R&D Project of China(2021YFB3400704)China State Railway Group(K2022J004 and N2023J011)China Railway Chengdu Group(CJ23018).
文摘Purpose–The safety and reliability of high-speed trains rely on the structural integrity of their components and the dynamic performance of the entire vehicle system.This paper aims to define and substantiate the assessment of the structural integrity and dynamical integrity of high-speed trains in both theory and practice.The key principles and approacheswill be proposed,and their applications to high-speed trains in Chinawill be presented.Design/methodology/approach–First,the structural integrity and dynamical integrity of high-speed trains are defined,and their relationship is introduced.Then,the principles for assessing the structural integrity of structural and dynamical components are presented and practical examples of gearboxes and dampers are provided.Finally,the principles and approaches for assessing the dynamical integrity of highspeed trains are presented and a novel operational assessment method is further presented.Findings–Vehicle system dynamics is the core of the proposed framework that provides the loads and vibrations on train components and the dynamic performance of the entire vehicle system.For assessing the structural integrity of structural components,an open-loop analysis considering both normal and abnormal vehicle conditions is needed.For assessing the structural integrity of dynamical components,a closed-loop analysis involving the influence of wear and degradation on vehicle system dynamics is needed.The analysis of vehicle system dynamics should follow the principles of complete objects,conditions and indices.Numerical,experimental and operational approaches should be combined to achieve effective assessments.Originality/value–The practical applications demonstrate that assessing the structural integrity and dynamical integrity of high-speed trains can support better control of critical defects,better lifespan management of train components and better maintenance decision-making for high-speed trains.
基金Shenzhen Municipal Science and Technology Innovation Commission Projects(Grant Nos.Y01336107,JCYJ20180504165824643,GJHZ20180411143506667,JC YJ20170817111811303 and KQTD20190929172505711)。
文摘This study is concerned with the surface integrity of Inconel 738LC parts manufactured by selective laser melting(SLM)followed by high-speed milling(HSM).In the investigation process of surface integrity,the study employs ultradepth three-dimensional microscopy,laser scanning confocal microscopy,scanning electron microscopy,electron backscatter diffractometry,and energy dispersive spectroscopy to characterize the evolution of material microstructure,work hardening,residual stress coupling,and anisotropic effect of the building direction on surface integrity of the samples.The results show that SLM/HSM hybrid manufacturing can be an effective method to obtain better surface quality with a thinner machining metamorphic layer.High-speed machining is adopted to reduce cutting force and suppress machining heat,which is an effective way to produce better surface mechanical properties during the SLM/HSM hybrid manufacturing process.In general,high-speed milling of the SLM-built Inconel 738LC samples offers better surface integrity,compared to simplex additive manufacturing or casting.
基金funded by the Sinopec Science and Technology Department Project(P21056).
文摘Generally,the so-called expansion agent is very effective in eliminating all the micro-annuli that exist between the casing and the cement sheath or between the cement sheath and the formation.However,this approach can detrimentally affect the sealing ability of cement sheath if the expansion agent is used in an unreasonable way.For these reasons,in the present work,numerical simulations have been conducted to analyze the effect of elasticity modulus of cement sheath,the elasticity modulus of formation,the expansion rate of cement,the geo-stress on the micro-annulus caused by cement expansion,and the cement sheath expansion on the integrity of cement sheath and formation.The micro-annulus between the casing and the cement sheath has been found to decrease according to the ratio between the elasticity modulus of formation and the elasticity modulus of cement sheath.A positive correlation has been observed between the micro-annulus and the cement expansion ratio.The microannulus decreases as the geo-stress increases,but the effect of the geo-stress on the micro-annulus is much smaller.In conclusion,the expansion agent is suitable for the formation in which the elasticity modulus is higher than the cement sheath.
基金Projects(51275530,51535012) supported by the National Natural Science Foundation of ChinaProject(2011CB706800) supported by the National Basic Research Program of China
文摘Aiming at the issue of the grinding integrity of face-gear with worm wheel, the envelope mathematical model of shaper, worm wheel and face-gear is established based on theories of differential geometry and gear mesh. The judgment of completely grinding the face-gear with the avoidance of singularities is established, and the mathematical expression to show the reason why singularities appear is derived, through the research on the surface contact area and singularity rules of the worm thread surface. The disadvantage of current face-gear grinding method that only part of the working surface of the face-gear can be covered is analyzed and the influence of coefficient of judgment is studied through changing the design parameters.
文摘To evaluate the new designed cutting tools for high-efficiency milling of the hardened die steel SKD11,surface integrities of millers with different geometric structures are analyzed, considering the surface roughness, micrograph of chips, surface microhardness, residual stress and metallurgical texture of the surface layer. The in fluences of geometric characteristics of different cutting tools and their wear characteristics on the surface integrity are studied. Results show that the milling tool with rake angle; 5 of the hardened diesteel. The generation of saw-tooth chips is depressed when a reasonable positive rake angle is selected. And the compressive residual stress is induced on the machined surface in milling the hardened die steel. The occurrence of surface softening is postponed by increasing the clearance angle and reducing the tool flank wear.
文摘An experimental study was carried out to investigat e the influence of temperatures on workpiece surface integrity in surface grinding of a cast nickel-based superalloy with alumina abrasive wheels. Temperatur e response at the wheel-workpiece interface was measured using a grindable foil /workpiece thermocouple. Specimens with different grinding temperatures were obt ained through changing grinding conditions including depth of cut, workpiece fee d speed, and coolant supply. Changes in surface roughness, residual stress, meta llographies, ground surface morphology, and micro hardness on the specimens were then analyzed. Bending fatigue tests were separately conducted at room temperat ure and 950oC in an effort to evaluate the influence of temperatures on the serv ice life of the ground specimens. A different burning color was found on the gro und workpiece surfaces when grinding temperatures are over a critical value. Alo ng with the emergence of burning color, roughness of the ground workpiece surfac e increased greatly compared with the surfaces without burning color, which was attributed to the plastically deformed coatings on the workpiece surface with el evated temperatures. Excepting the surface roughness, other items concerning the surface integrity of the ground workpiece were not affected by temperatures pro vided that grinding temperatures are not high enough to cause grinding cracks. B ased on the findings in this study, the grinding of the nickel-based superalloy can be divided into two stages in order to increase production efficiency, in which case the first stage is to reach an high material removal rate without concerning of the presence of burning color, whereas the second stage is to remo ve the plastically deformed coatings in order to decrease surface roughness.
基金Project (No. 50478022) supported by the National Natural Science Foundation of China
文摘The principle and process of parallel seismic (PS) testing for the integrity testing of cemented soil columns are in- troduced in this paper. A three-dimensional (3D) finite element model (FEM) for the pile-soil system is established for impulse responses. Under saturated soil or unsaturated soil condition, several vibrating velocity-time histories at different depths in parallel hole are obtained based on the numerical simulation. It shows that the length of the pile and the one-dimensional (1D) P-wave velocity in the pile can be determined easily from the features of the mentioned velocity-time histories. By examining the slopes of the first arrival time plotted versus depth or the depth where the amplitude of the first arrival significantly decreases, the length of the pile can be determined. The effects of the 3D P-wave propagation through the saturated soil and the defect of the cemented soil column on the velocity-time histories are also investigated.
基金Supported by Shenzhen Municipal Science and Technology Innovation Commission of China(Grant Nos.Y01336107,GJHZ20180411143506667,JCYJ20170817111811303).
文摘The Ti6Al4V parts produced by the existing selective laser melting(SLM)are mainly confronted with poor surface finish and inevitable interior defects,which substantially deteriorates the mechanical properties and performances of the parts.In this regard,ultrasonically-assisted machining(UAM)technique is commonly introduced to improve the machining quality due to its merits in increasing tool life and reducing cutting force.However,most of the previous studies focus on the performance of UAM with ultrasonic vibrations applied in the tangential and feed directions,whereas few of them on the impact of ultrasonic vibration along the vertical direction.In this study,the effects of feed rate on surface integrity in ultrasonically-assisted vertical milling(UAVM)of the Ti6Al4V alloy manufactured by SLM were systemically investigated compared with the conventional machining(CM)method.The results revealed that the milling forces in UAVM showed a lower amplitude than that in CM due to the intermittent cutting style.The surface roughness values of the parts produced by UAVM were generally greater than that by CM owing to the extra sinusoidal vibration textures induced by the milling cutter.Moreover,the extra vertical ultrasonic vibration in UAVM was beneficial to suppressing machining chatter.As feed rate increased,surface microhardness and thickness of the plastic deformation zone in CM raised due to more intensive plastic deformation,while these two material properties in UAVM were reduced owing to the mitigated impact effect by the high-frequency vibration of the milling cutter.Therefore,the improved surface microhardness and reduced thickness of the subsurface deformation layer in UAVM were ascribed to the vertical high-frequency impact of the milling cutter in UAVM.In general,the results of this study provided an in-depth understanding in UAVM of Ti6Al4V parts manufactured by SLM.
基金This is a part of the project (No. 010399) supported by Natural Science Foundation of Guangdong Province,China.
文摘Objective To determine the membrane integrity in the head and tail regions of individual spermatozoon, and observe sperm morphology for samples with totally immotile sperm. Methods Ten infertile men with immotile sperm were enrolled into this study (group A). The membrane integrity in the head and tail regions of individual spermatozoon of immotile sperm was examined by using the combined hypo-osmotic swelling-eosin Y exclusion test (HOS-EY test). Sperm morphology was observed by light, scanning and transmission electron microscopy. Ten semen samples from normospermic donors were used as the control (group B). Results The percentage of sperm with intact both head and tail membranes in group A was significantly lower than that in group B (P〈0.01), whereas the value of sperm with defective head membrane but intact tail membrane in group A was significantly higher than that in group B (P〈0.01). Abnormal sperm morphology in group A had a high incidence, and immotile sperm with viability and normal morphology could be observed in some cases. Most sperm had multiple ultrastructural defects. Conclussion Some immotile sperm had intact tail membrane but defective head membrane. Immotile sperm with viability and normal morphology could exist in some cases though abnormal sperm were in a great proportion. Carefully evaluating immotile sperm membrane integrity and morphology should benefit the treatment of patients with immotile sperm.
基金the National Natural Science Foundation of China,the National Basic Research Program of China ("973" Program) the National High Technology Research and Development Program of China ("863" Program)
文摘Cloud computing and storage services allow clients to move their data center and applications to centralized large data centers and thus avoid the burden of local data storage and maintenance.However,this poses new challenges related to creating secure and reliable data storage over unreliable service providers.In this study,we address the problem of ensuring the integrity of data storage in cloud computing.In particular,we consider methods for reducing the burden of generating a constant amount of metadata at the client side.By exploiting some good attributes of the bilinear group,we can devise a simple and efficient audit service for public verification of untrusted and outsourced storage,which can be important for achieving widespread deployment of cloud computing.Whereas many prior studies on ensuring remote data integrity did not consider the burden of generating verification metadata at the client side,the objective of this study is to resolve this issue.Moreover,our scheme also supports data dynamics and public verifiability.Extensive security and performance analysis shows that the proposed scheme is highly efficient and provably secure.
文摘A-Jacks are concrete armor units that are used in both open channel and coastal applications.In open channel applications,they are used for bank and toe protection,flow and grade control,bridge pier scour protection,energy dissipation,and habitat.These small units may be fabricated in standard block machines.In coastal applications,A-Jacks are used in breakwaters,jetties,revetments,and habitat development.Coastal units are generally much larger and more robust than the small open channel units.This paper focuses on coastal applications and in particular,combines results on three topics:(1)recent hydraulic model studies,(2)alternative fabrication methods,and(3)bundle placement construction methods.Hydraulic models studies were conducted that examined the standard random and uniform placement methods,and also the bundle placement method.In bundle placement,3~20 A-Jacks are banded together,lifted with a spreader bar,and placed as a single crane pick.This significantly decreases installation time during construction.It also provides a more hydraulically stable placement technique.The hydraulic model tests examined the bundle stability in random waves for cases where the binding remains in tack and is removed.The geometry of A-Jacks enables a variety of fabrication techniques.One option is to fabricate the A-Jacks as two pieces using flat forms and then grout the two pieces together.Flat forms may be used in conventional block machines for A-Jacks sizes up to 1.3 m.Larger sizes may be wet cast in flat forms or gang forms.The A-Jacks geometry has been recently modified to increase grouting efficient and strength.Large A- Jacks may also be cast in a single piece using 'clam shell' type forms.
文摘Ten years after the initial generation of induced pluripotent stem cells(hiPSCs)from human tissues,their potential is no longer questioned,with over 15000 publications listed on PubMed,covering various fields of research;including disease modeling,cell therapy strategies,pharmacology/toxicology screening and 3D organoid systems.However,despite evidences that the presence of mutations in hiPSCs should be a concern,publications addressing genomic integrity of these cells represent less than 1%of the literature.After a first overview of the mutation types currently reported in hiPSCs,including karyotype abnormalities,copy number variations,single point mutation as well as uniparental disomy,this review will discuss the impact of reprogramming parameters such as starting cell type and reprogramming method on the maintenance of the cellular genomic integrity.Then,a specific focus will be placed on culture conditions and subsequent differentiation protocols and how their may also trigger genomic aberrations within the cell population of interest.Finally,in a last section,the impact of genomic alterations on the possible usages of hiPSCs and their derivatives will also be exemplified and discussed.We will also discuss which techniques or combination of techniques should be used to screen for genomic abnormalities with a particular focus on the necessary quality controls and the potential alternatives.
基金This research work was supported by the National Science Foundations of USA through the NSF Grant DMI-9908319. The research support from Center for Robotics and Manufacturing Systems, University of Kentucky, was greatly acknowledged.
文摘In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the thermal distribution at the brazed joint zone is related to not only the geometry of the fin and tube, butalso the brazed joint topology. A poor brazed joint will result in very poor heat transfer. Thermal contact resistanceis adopted to analyze the fin heat efficiency.
基金supported in part by National Natural Science Foundation of China under Grant (61070164,61272415)Natural Science Foundation of Guangdong Province, China under Grant (S2012010008767)Science and Technology Planning Project of Guangdong Province, China under Grant (2013B010401015)
文摘Unauthorized tampering with outsourced data can result in significant losses for both data owner and users.Data integrity therefore becomes an important factor in outsourced data systems.In this paper,we address this problem and propose a scheme for verifying the integrity of outsourced data.We first propose a new authenticated data structure for authenticating membership queries in sets based on accumulators,and then show how to apply it to the problem of verifying the integrity of outsourced data.We also prove that our scheme is secure under the q-strong DiffieHellman assumption.More importantly,our scheme has the constant cost communication,meanwhile keeping other complexity measures constant.Compared to previous schemes based on accumulators,our scheme reduces update cost and so improves previous schemes based on accumulators.In addition,the experimental comparison shows that our scheme outperforms the previous schemes.
基金Supported by Key Project of the National Science&Technology Pillar Program during the Twelfth Five-year Plan Period(2013BAD01B0106)the Special Scientific Research Fund of Shandong Academy of Agricultural Sciences for Young Scholars(2016YQN19)+4 种基金China Agriculture Research System-Green Manure(CARS-22)National Crop Germplasm Resources Platform of China(2012/2013-032)Major Scientific and Technological Innovation Project of Shandong Province(2017CXGC0311)Modern Agricultural Industry Technology System of Shandong Province(SDAIT-15-01)Special Fund of Shandong Academy of Agricultural Sciences for Innovation in Agricultural Science and Technology(CXGC2018E15)
文摘The seeds of a soybean cultivar Zhonghuang 18 were subjected to accelerated aging for 0(population G_0-1), 112(population G_0-2), 154(population G_0-3) and 196 d(population G_0-4), whose germination percentage was found to be 98.0%, 95.0%, 81.0%, and 79.0%, respectively. Then, the four populations were regenerated twice in the field. The first descendant populations were marked as G_1-1, G_1-2, G_1-3 and G_1-4, and the second were marked as G_2-1, G_2-2, G_2-3 and G_2-4, respectively. The genetic variation between the control population(G_0-1) and the experimental populations was analyzed using 12 AFLP primer combinations. The results showed that there was no significant difference in genetic similarity between the 11 experimental populations and the control population G_0-1. The genetic similarity between population G_2-4 and G_0-1 was still as high as 0.933 3, indicating that the F_2 generation of the population whose germination percentage was only 79.0% still had a high genetic similarity to the control population. The results of t-tests revealed that the populations G_1-1, G_2-1, G_1-2 and G_2-2 showed no significant difference from the control population G_0-1 in effective number of alleles per locus(Ae), genetic diversity index(H) and Shannon's diversity index(I), while these indices of populations G_0-3, G_0-4, G_1-3, G_1-4, G_2-3 and G_2-4 were significantly reduced. χ~2 tests indicated that the populations G_1-1 and G_2-1 showed little difference, and the populations G_0-2, G_0-3, G_0-4, G_1-2, G_1-3, G_1-4, G_2-2, G_2-3, and G_2-4 showed great difference in allele frequency distribution from the control population G_0-1, and the difference was greater when the seed viability was lower. Compared with the control population G_0-1, the number of rare alleles(Nr) of the populations G_0-2, G_1-1, G_2-1, G_1-2 and G_2-2 showed no significant difference, while that of the populations G_0-3, G_0-4, G_1-3, G_1-4, G_2-3 and G_2-4 declined obviously. These results revealed that compared with the control population, the genetic diversity and Nr for the descendant populations of the populations with 98.0% and 95.0% germination percentages did not change significantly, but declined greatly for the descendant populations of the populations with 81.0.% and 79.0% percentages. The results suggested that the decline in seed viability has a greater impact than the number of generations on genetic structure of soybean germplasm. So, it is suggested that soybean seed with an initial germination percentage of 98.0% should be regenerated before its germination percentage declines to 81.0%.
文摘One of the major problems associated with the therapeutic application of β-lactam antibiotics is their significant instability [1]-[3]. Analogs from that group are easily degraded in aqueous solutions and in solid state, which happens predominantly as a result of β-lactam ring chemical degradation. Because of this, the chemical integrity of β-lactam antibiotics must be closely monitored to meet FDA requirements. The original iodometric method based on visual detection of the end products of beta-lactamase hydrolysis that has been used to test beta-lactamase activity [4] was modified to quantitatively assess the amount of degraded product in amoxicillin. A UV-visible spectrophotometric method has been used, focusing on the ability of the products from the degradation of β-lactam analogs to absorb iodine from bulk solution, resulting in a significant reduction in the absorption spectra. Amoxicillin trihydrate tablets with different expiration dates and amoxicillin samples pre-loaded with known amounts of degraded amoxicillin have been used to generate a calibration curve and quantify the presence of degraded materials. Results show that the changes in the absorption spectra of iodine reagent directly correlate with the fraction of degraded β-lactam antibiotics, such as amoxicillin, in commercial products. The proposed assay might be as close as one step from simpler and cheaper methods of quantitative analysis of degraded β-lactam analogs, with estimated sensitivity in the range of 1% - 2%, which is better than the current FDA requirements.
文摘The domination integrity of a connected graph G= (V(G), E(G)) is denoted as DI(G) and defined by DI(G) = min{*S*+ m(G-S) : S is a dominating set } where m(G-S) is the order of a maximum component of G-S . We discuss domination integrity in the context of some graph operations like duplication of an edge by vertex and duplication of vertex by an edge.
文摘Rare earth elements have been extensively used as micro-fertilizers for crops in China. To?understand the potential benefits or damages of Ce4+ on rice, the effects of Ce4+ on viability and membrane integrity of rice were investigated under hydroponic cultures. It has been found that the cell viability, electrical conductivity, pH changes, and concentration of malonyl dialdehyde did not change obviously when the content of Ce4+ was 0.5 mg/L, but varied markedly when the contents of Ce4+ were raised to 10 mg/L or more, indicating that the Ce4+ at higher concentrations severely affected the cell membrane permeability.
文摘In an addition to the variety of topics in aims and scope of the Journal of International Relations and Diplomacy, we would be happy to offer here some more areas in line with its general orientation, which could be worth investigating, encouraging more paper submissions. These relate to effective organization of large distributed dynamic systems of diverse natures which may require innovative solutions reflecting the growing world dynamics in the 21 st century with emerging challenges and threats to local and global prosperity, stability, and safety.