Transfer RNA-derived small RNAs(tsRNAs)have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells.However,it is unknown whether tsRNAs also regulate...Transfer RNA-derived small RNAs(tsRNAs)have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells.However,it is unknown whether tsRNAs also regulate embryo hatching.In this study,we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA(miRNA)cargo of preimplantation embryonic extracellular vesicles(EVs)influences embryo development.We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts.The majority of tsRNAs was identified as tRNA halves originating from the 5'ends of tRNAs.Among the 148 differentially expressed tsRNAs,the 19 nt tRNA fragment(tRF)tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts.RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group(P<0.05).Inhibition of tDR-14:32-Glu-CTC-1 by supplementing antagomirs to the conditioned medium improved embryo hatching(P<0.05).Transcriptomic analysis of embryos treated with tDR-14:32-Glu-CTC-1 antagomirs further showed differential expression of genes that are associated with embryo hatching and implantation.In summary,tDR-14:32-Glu-CTC-1 is up-regulated in non-blastocyst embryos and their secretions,and inhibition of tDR-14:32-Glu-CTC-1 promotes embryo hatching,while influencing embryo implantation-related genes and pathways.These results indicate that embryonic EVs containing specific tRFs may regulate preimplantation embryo development.展开更多
With the rapid growth of the global digital economy, cross-border e-commerce, as an emerging form of trade, has gradually become a powerful engine to promote the development of global trade. BRICS is an important forc...With the rapid growth of the global digital economy, cross-border e-commerce, as an emerging form of trade, has gradually become a powerful engine to promote the development of global trade. BRICS is an important force in the global economy, and the progress of the BRICS countries' trade facilitation level has an important impact on the global trade environment. This paper conducts an in-depth study of the dynamic changes in BRICS trade facilitation from 2013 to 2022, and uses an extended gravity model to analyze the specific impact of this change on China's exports using cross-border e-commerce. The results show that although the BRICS countries have made some progress in trade facilitation, the overall level still needs to be improved, and there are obvious differences among member countries. However, the improvement of trade facilitation among BRICS countries has undoubtedly brought significant positive effects to China's exports using cross-border e-commerce.展开更多
High speed photography technique is potentially the most effective way to measure the motion parameter of warhead fragment benefiting from its advantages of high accuracy,high resolution and high efficiency.However,it...High speed photography technique is potentially the most effective way to measure the motion parameter of warhead fragment benefiting from its advantages of high accuracy,high resolution and high efficiency.However,it faces challenge in dense objects tracking and 3D trajectories reconstruction due to the characteristics of small size and dense distribution of fragment swarm.To address these challenges,this work presents a warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography.Firstly,background difference algorithm is utilized to extract the center and area of each fragment in the image sequence.Subsequently,a multi-object tracking(MOT)algorithm using Kalman filtering and Hungarian optimal assignment is developed to realize real-time and robust trajectories tracking of fragment swarm.To reconstruct 3D motion trajectories,a global stereo trajectories matching strategy is presented,which takes advantages of epipolar constraint and continuity constraint to correctly retrieve stereo correspondence followed by 3D trajectories refinement using polynomial fitting.Finally,the simulation and experimental results demonstrate that the proposed method can accurately track the motion trajectories and reconstruct the spatio-temporal distribution of 1.0×10^(3)fragments in a field of view(FOV)of 3.2 m×2.5 m,and the accuracy of the velocity estimation can achieve 98.6%.展开更多
To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept,this paper proposes a method for calculating target damage p...To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept,this paper proposes a method for calculating target damage probability leveraging spatio-temporal finite multilayer fragments distribution and the target damage assessment algorithm based on cloud model theory.Drawing on the spatial dispersion characteristics of fragments of projectile proximity explosion,we divide into a finite number of fragments distribution planes based on the time series in space,set up a fragment layer dispersion model grounded in the time series and intersection criterion for determining the effective penetration of each layer of fragments into the target.Building on the precondition that the multilayer fragments of the time series effectively assail the target,we also establish the damage criterion of the perforation and penetration damage and deduce the damage probability calculation model.Taking the damage probability of the fragment layer in the spatio-temporal sequence to the target as the input state variable,we introduce cloud model theory to research the target damage assessment method.Combining the equivalent simulation experiment,the scientific and rational nature of the proposed method were validated through quantitative calculations and comparative analysis.展开更多
The double casing warhead with sandwiched charge is a novel fragmentation warhead that can produce two groups of fragments with different velocity,and the previous work has presented a calculation formula to determine...The double casing warhead with sandwiched charge is a novel fragmentation warhead that can produce two groups of fragments with different velocity,and the previous work has presented a calculation formula to determine the maximum fragment velocity.The current work builds on the published formula to further develop a formula for calculating the axial distribution characteristics of the fragment velocity.For this type of warhead,the simulation of the dispersion characteristics of the detonation products at different positions shows that the detonation products at the ends have a much larger axial velocity than those in the middle,and the detonation products have a greater axial dispersion velocity when they are closer to the central axis.The loading process and the fragment velocity vary with the axial position for both casing layers,and the total velocity of the fragments is the vector sum of the radial velocity and the axial velocity.At the same axial position,the acceleration time of the inner casing is greater than that of the outer casing.For the same casing,the fragments generated at the ends have a longer acceleration time than the fragments from the middle.The proposed formula is validated with the X-ray radiography results of the four warheads previously tested experimentally and the 3D smoothedparticle hydrodynamics numerical simulation results of several series of new warheads with different configurations.The formula can accurately and reliably calculate the fragment velocity when the lengthto-diameter ratio of the charge is greater than 1.5 and the thickness of the casing is less than 20%its inner radius.This work thus provides a key reference for the theoretical analysis and the design of warheads with multiple casings.展开更多
This study delves into the bilateral relations between Iran and Turkmenistan,focusing on the multidimensional impacts of cross-border ethnic groups,cultural diplomacy,and energy cooperation.The research reveals that d...This study delves into the bilateral relations between Iran and Turkmenistan,focusing on the multidimensional impacts of cross-border ethnic groups,cultural diplomacy,and energy cooperation.The research reveals that despite challenges in security cooperation,such as regional political ideological differences and uneven power distribution,Iran has adopted diverse strategies to enhance cultural identity,social cohesion,and promote economic cooperation.Iran actively seeks to repair relations with Turkmenistan by emphasizing shared historical and cultural backgrounds,particularly the presence of cross-border Turkmen ethnic groups.Specific measures include developing cultural tourism,organizing cultural weeks,and establishing commemorative days.In the economic sphere,the two countries have signed significant natural gas supply agreements,strengthening energy cooperation.Iranian leaders often emphasize“blood ties”and deep cultural connections in diplomatic statements,combining cultural diplomacy with practical economic cooperation.The study’s findings indicate that Iran’s initiatives have led to the reorganization of national space and social reconstruction in border regions,promoting changes in public policy.By integrating cultural identity,historical connections,and economic interests,Iran has adopted a sophisticated diplomatic approach,laying the foundation for more stable and enduring bilateral relations while contributing to regional stability and sustainable development.展开更多
This paper explores the operational strategies of cross-border micro, small, and medium enterprises (MSMEs). Against the backdrop of globalization and digitalization, cross-border trade has become one of the important...This paper explores the operational strategies of cross-border micro, small, and medium enterprises (MSMEs). Against the backdrop of globalization and digitalization, cross-border trade has become one of the important pathways for many MSMEs to achieve growth and competitive advantage. Firstly, the paper outlines the concept and characteristics of cross-border MSMEs, as well as the analysis of their operational environment in the context of globalization, including political, economic, social, technological, environmental, and legal factors. Secondly, the paper proposes operational strategies for cross-border MSMEs, including international market selection and positioning, cross-border marketing strategies, supply chain management, cross-border financial management, and cross-border risk management. Finally, the paper summarizes the importance of effectively implementing these strategies for cross-border MSMEs to seize international market opportunities, reduce operational risks, and enhance competitiveness and profitability.展开更多
The limestone region in southwestern Guangxi contains the most typical karst landforms in the world. Due to their destruction, the original forests mainly survive in nature reserves in the form of fragmented areas. Fr...The limestone region in southwestern Guangxi contains the most typical karst landforms in the world. Due to their destruction, the original forests mainly survive in nature reserves in the form of fragmented areas. From June 2009 to September 2010 we conducted an investigation of 13 relatively isolated habitats or sites, selected from each of the 13 nature reserves in southwestern Guangxi, with the least amount of anthropological activity and the largest presence of the original vegetation, in order to study the distribution of birds on forest fragments. The distribution patterns of the birds and the factors which affect them were analyzed by using the 'BINMATNEST' software and the Spearman’s rank correlation analysis, to determine: 1) whether nested patterns of birds in the karst area of southwestern Guangxi exist or not and 2) which factors are correlated with the nested patterns and the effect of these factors on forming nested patterns. The results show that the birds had statistically significant nested patterns in the karst area and the specificity of the habitat of the birds had a significant effect on the nested patterns. We suggest possible reasons for these results, based on the characteristics of the seasonal tropical rain forests in the study area and on neutral theory. We also urgently recommend that close attention be paid to the protection of the diversity of the environment for birds in all fragmented habitats.展开更多
Two acetylcholinesterase (AChE) genes cDNA fragments,Ag.acel and Ag.ace2,have been cloned from cotton aphid,Aphis gossypii Glover using degenerate primers with RT-PCR technique.Ag.acel gene cDNA fragment is of 282?bp ...Two acetylcholinesterase (AChE) genes cDNA fragments,Ag.acel and Ag.ace2,have been cloned from cotton aphid,Aphis gossypii Glover using degenerate primers with RT-PCR technique.Ag.acel gene cDNA fragment is of 282?bp encoding 94 amino acids,and Ag.ace2 gene cDNA fragment is of 264?bp encoding 88 amino acids.Both two putative AChE genes cDNA fragments share numerous similarities with those cloned from other insects.This is the first report of two AChE cDNA fragment sequences in the insect species,which provided the direct evidence of multiple AChE existence in insects.展开更多
[Objective] The study aimed at evaluating the uncertainty in measuring the construct-specific fragments of genetically modified maize MON863 by real time quantitative PCR.[Method] The content of construct-specific fra...[Objective] The study aimed at evaluating the uncertainty in measuring the construct-specific fragments of genetically modified maize MON863 by real time quantitative PCR.[Method] The content of construct-specific fragments in MON863 samples was determined by real time quantitative PCR,and then the uncertainty of measurement result was evaluated according to the sources of uncertainty like the PCR system,the data processing and the micropipette.[Result] Type A evaluation of uncertainty(uA) in the measurement was 1.7×10^-2;Type B evaluation of uncertainty(uB) was 9.0×10^-4;the combined standard uncertainty(uC) was 1.7×10^-2;the expanded uncertainty(U95) was 0.036 and the finally measured result was 1.08%±0.036.[Conclusion] The main uncertainty of the result measured by real time quantitative PCR came from the randomizing effect in the experimental process.展开更多
In this paper, sinking and growth of apexes and mid-stems of Myriophyllum spicatum L., Hydrilla verticillata (L.f.) Royle and Ceratophyllum demersum L. in concrete ponds containing eutrophic water and sediment were ...In this paper, sinking and growth of apexes and mid-stems of Myriophyllum spicatum L., Hydrilla verticillata (L.f.) Royle and Ceratophyllum demersum L. in concrete ponds containing eutrophic water and sediment were investigated. Sinking rates of apexes and mid-stems reached 34.8% and 4.4% at the 6 th day and 91.1% and 66.7% at the 22 nd day for M. spicatum, 57.8% and 55.6% at the 6 th day and 100% and 97.8% at the 22 nd day for H. vertieillata, 18.9% and 86.7% at the 6 th day and 95.6% and 100% at the 22 nd day for C. demersum, respectively. Most sunken fragments established themselves successfully with significant growth. Total shoot length ofplantlets developed from apexes and mid-stems increased by 399% and 61% for M. spicatum, 593% and 256% for H. vertieillata and 114% and 104% for C. demersum, respectively. The results showed that it was feasible to establish submersed macrophytes via sinking and colonization of shoot fragments clipped off manually.展开更多
Fractures running along a plane reflect the cracking progress.In this paper uniaxial and rockburst tests on a group of granite specimens from Sanya province are described.Scanning electron microscopic imaging was used...Fractures running along a plane reflect the cracking progress.In this paper uniaxial and rockburst tests on a group of granite specimens from Sanya province are described.Scanning electron microscopic imaging was used to characterize the fragments.Fractal fracture mechanics were used to analyze the microcracks in terms of both the crack type and the mineral constituent.A statistical analysis showed that the area of inter-granular cracking exceeds that of intra-granular cracking.Several types of crack were observed in the cracked areas.The percentage of intra-granular cracks in fragments from rockburst tests exceeds that from uniaxial compression tests.The results also showed that feldspar deformation was the main cause of fracture and that the consolidation along quartz grain boundaries was another weak area in the granite.Cracking along quartz grains had enough energy to enter the quartz crystal in the rockburst samples.All these results contribute to further research on rockburst mechanics.展开更多
Transposable elements have been utilized as mutagens to create mutant libraries for functional genomics. Isolation of genomic segments flanking the insertion Mutator (Mu) is a key step in insertion mutagenesis studi...Transposable elements have been utilized as mutagens to create mutant libraries for functional genomics. Isolation of genomic segments flanking the insertion Mutator (Mu) is a key step in insertion mutagenesis studies. Herein, we adopted a modified AFLP method to identify and isolate Mu-flanking fragments from maize. The method consists of the following steps: 1) double-digestion of genomic DNA with Bgl II/Msp I and ligation of digested fragments to the Bgl II- and Msp I-adaptors; 2) enrichment of a subset of Bgl II/Msp I fragments followed by selective amplification of the Mu-flanking fragments; 3) simultaneous display of AFLP bands derived from the flanking regions for both insert and native Mu transposons; 4) identification and isolation of AFLP bands resulting from Mu insertions by comparing the banding profiles between Mu-induced mutants and their parental lines; and 5) confirmation of flanking fragments related to these Mu insertions. Using this approach, we have isolated flanking fragment(s) resulting from Mu insertion for every Mu-induced mutant, and one such fragment, M196-FF, is found to contain a partial sequence of the DNA topoisomerase I gene Topl. Moreover, the modified AFLP method including all restriction enzymes, adaptors and primers has been optimized in this study. The modified AFLP method has been proved to be simple and efficient in the isolation of Mu-flanking fragments and will find its usefulness in the functional genomics of maize.展开更多
3 degrees of freedom(DOF)exterior ballistic computer models are used in fragment studies to calculate individual trajectories of each fragment based on drag coefficient and the projected(presented)area in the directio...3 degrees of freedom(DOF)exterior ballistic computer models are used in fragment studies to calculate individual trajectories of each fragment based on drag coefficient and the projected(presented)area in the direction of velocity of center of mass.The expectation of a randomly distributed projected area is commonly used for fragments that tumble(random rotation)during flight.We forecast a model where the expected drag coefficient is dependent of shape and Mach number.Rotation or tumbling only affects the expected projected area.Models of projected areas during tumbling and rotation are presented.An examination of the data by Mc Cleskey(1988)indicates that the volume of the fragment to the power of2/3 is a better parameter to characterize the drag coefficient of the fragments than the maximum projected area.Hydrocode simulations are used to verify results and to study projected area and drag coefficient of fragments.展开更多
AIM: To investigate the state of the art regarding Cartilage Autograft Implantation System(CAIS) or Particulated Juvenile Allograft Cartilage(PJAC).METHODS: The authors searched the English literature regarding CAIS a...AIM: To investigate the state of the art regarding Cartilage Autograft Implantation System(CAIS) or Particulated Juvenile Allograft Cartilage(PJAC).METHODS: The authors searched the English literature regarding CAIS and PJAC. The search strategy was:(particulated cartilage) OR autologous cartilage fragments. All basic science articles were included. Clinical articles with less than 10 patients treated and less than 6 mo of follow-up were excluded. With these criteria, a total of 17 articles were available for the present review. RESULTS: PJAC and CAIS are relatively novel techniques for cartilage repair. Good basic science evidence was described to support the concept. Although the preliminary clinical reports show encouraging results, clinical data are still limited, especially for CAIS. The indications for both techniques need to be precisely defined(age of the patients, size of the lesion, and involvement of the subchondral bone), together with other debated issues. CONCLUSION: In conclusion, the authors can state that encouraging preliminary results are available for both techniques. However, further studies are necessary to precisely determine the indications, surgical techniques, and long term outcomes for PJAC and CAIS.展开更多
AIM: To evaluate the outcomes of "concurrent vitrectomy" to retrieve dislocated lens fragment during phacoemulsification.METHODS: In a retrospective, observational case series, data of patients who underwent...AIM: To evaluate the outcomes of "concurrent vitrectomy" to retrieve dislocated lens fragment during phacoemulsification.METHODS: In a retrospective, observational case series, data of patients who underwent "concurrent" pars plana vitrectomy(PPV) for dislocated lens fragments between the period 2000 and 2008 were reviewed. Data collected included patient demographics, pre-operative visual acuity, intra-operative occurrence of retinal breaks, duration of follow up, post-operative intraocular pressure, final best-corrected visual acuity(BCVA),presence of cystoid macular edema(CME) and occurrence of rhegmatogenous retinal detachment(RRD).· RESULTS: A total of 58 eyes of 58 patients were included in the study. At 12 mo the mean postoperative BCVA was log MAR 0.17(20/30) with a range of log MAR0 to 0.69(20/20 to 20/100), with 96.6%(56/58) of patients showing post- operative improvement in visual acuity(P =0.005). None of the patients developed postoperative retinal detachment, endophthalmitis or non-resolving uveitis at 12 mo.CONCLUSION: Our study results suggest concurrent PPV for retained lens fragments after cataract surgery is beneficial and may decrease the risk of glaucoma and prevent development of RRD.展开更多
The essence and the main contribution of this paper are consisted of the suggested novel method for estimation of a projected surface area of an irregularly shaped fragment, which represents a significant step toward ...The essence and the main contribution of this paper are consisted of the suggested novel method for estimation of a projected surface area of an irregularly shaped fragment, which represents a significant step toward a new method of an aerodynamic force estimation of a fragment motion through a resistive medium. The suggested method is to use a tri-axial ellipsoid that has a continuous surface(given as a mathematical function) to approximate an irregularly shaped fragment so that the fragment trajectory can be estimated faster taking into consideration that the aerodynamic force is proportional to a projected surface area of the fragment.During their motion, fragments can take any orientation relative to the velocity vector and aerodynamic force is proportional to a projected surface area of fragment perpendicular to the velocity vector,so it is necessary to have a method for correct estimation of the projected area in an arbitrary direction relatively to the fragment.The model was validated with analytical and CAD techniques, and verified using 3D model of a real fragment. The comparison of the projected surface area values for the fragment, obtained using the CAD tools and using our model, are generally in good agreement, This method represents a step toward modeling that does not require a CFD result for estimation of the aerodynamic force of irregularly shaped bodies.展开更多
Probiotical cell fragments (PCFs) are structural components of the probiotic cell lysate(s) and exhibit similar beneficial effects on the host as live probiotic bacteria. With cell fragment technology (CFT?), the stru...Probiotical cell fragments (PCFs) are structural components of the probiotic cell lysate(s) and exhibit similar beneficial effects on the host as live probiotic bacteria. With cell fragment technology (CFT?), the structural fragments are isolated and purified from live probiotic cells. While observed to be strain-dependent as in the case of live probiotics, orally administered PCFs demonstrated a broad spectrum of immune modulation functions;anti-allergy;anti-inflammation;anti-bacterial and anti-viral properties;anti-mutagenic;and radioprotective and detoxification abilities in humans and animals. The PCFs mechanisms of action include events of motifs of cell wall peptidoglycans, DNA motifs, nucleotide containing components, lipoteichoic acids (LPAs), surface layer (S-layer) proteins, and cytoplasmic proteins. Different immunological in vivo-in vitro tests have shown that PCFs, essentially, have the ability to stimulate the macrophages, and induce cytokines such as interleukins, tumor necrosis factors (TNFs), interferons (IFNs), and natural killer (NK) cells. PCFs may be used as ingredients for foods and beverages or as nutritional supplements with long term stability and shelf-life up to 5 years. PCFs may also be used as health restorative ingredients in cosmetic products. The outcome of probiotics CFT? stands as an advantage to the food and pharmaceutical industries, regarding the formulation of novel products with unadulterated sensory characteristics of origin. Hence, PCFs are being characterized here as “novel nutraceutical ingredients” for health maintenance in both humans and animals.展开更多
In this study,we investigated the isospin properties of intermediate mass fragments(IMFs)for the central collisions of^(112,124)Sn+^(112,124)Sn at a beam energy of50 MeV per nucleon using an improved quantum molecular...In this study,we investigated the isospin properties of intermediate mass fragments(IMFs)for the central collisions of^(112,124)Sn+^(112,124)Sn at a beam energy of50 MeV per nucleon using an improved quantum molecular dynamics model(ImQMD)coupled with a sequential decay model(GEMINI).Three observables were analyzed:(1)the average center-of-mass kinetic energy per nucleon<Ec.m./A>of fragments as a function of their charge number Z;(2)the average neutron number to proton number ratio(<N>/Z)of fragments with a given charge number Z as a function of their center-of-mass kinetic energy per nucleon(Ec.m./A);and(3)the average total neutron number to total proton number ratio(ΣN/ΣZ)and double ratio(DR(N/Z))of IMFs with Z=3-8 as a function of their center-of-mass kinetic energy per nucleon Ec.m./A.Our calculations revealed that the sensitivity of the isospin properties of IMFs relative to the stiffness of the symmetry energy remains even after sequential decay.By comparing the calculations ofΣN/ΣZ and DR(N/Z)with the data,it was found that the soft symmetry energy,i.e.,γ=0.5,is favored.展开更多
A warhead with axial forward projection fragments is one of the most important forms of aimable warheads. For such warheads the axial forward projection fragments are placed at the end of the explosive charge and form...A warhead with axial forward projection fragments is one of the most important forms of aimable warheads. For such warheads the axial forward projection fragments are placed at the end of the explosive charge and form a fragment beam with high fragment density and high speed by the blast, which will obviously increase the damage to the targets. Experimental data showed that the velocities of the forward projection fragments on the convex end of a warhead which was initiated at the opposite end do not match that predicted by the Gurney equation for cylindrical warheads. A new approach for addressing the velocities of fragments of this kind of warhead is proposed. Two limiting conditions are defined, i.e. for fragment on the circumference of a cylindrical charge and fragments on the end of cylindrical charge, respectively.展开更多
基金supported by Ghent University(Grant:Bijzonder Onderzoeksfonds Geconcerteerde Onderzoeksactie 2018000504[GOA030-18 BOF])supported by Ghent University:BOF.STG.2022.02.0034.01+1 种基金supported by China Scholarship Council:Grant 202006910034supported by Fonds Wetenschappelijk Onderzoek:Grant 1228821N and 12A2H24N。
文摘Transfer RNA-derived small RNAs(tsRNAs)have been shown to be involved in early embryo development and repression of endogenous retroelements in embryos and stem cells.However,it is unknown whether tsRNAs also regulate embryo hatching.In this study,we mined the sequencing data of a previous experiment in which we demonstrated that the microRNA(miRNA)cargo of preimplantation embryonic extracellular vesicles(EVs)influences embryo development.We thus profiled the tsRNA cargo of EVs secreted by blastocysts and non-blastocysts.The majority of tsRNAs was identified as tRNA halves originating from the 5'ends of tRNAs.Among the 148 differentially expressed tsRNAs,the 19 nt tRNA fragment(tRF)tDR-14:32-Glu-CTC-1 was found to be significantly up-regulated in EVs derived from non-blastocysts.RT-qPCR assays confirmed its significant up-regulation in non-blastocyst embryos and their conditioned medium compared to the blastocyst group(P<0.05).Inhibition of tDR-14:32-Glu-CTC-1 by supplementing antagomirs to the conditioned medium improved embryo hatching(P<0.05).Transcriptomic analysis of embryos treated with tDR-14:32-Glu-CTC-1 antagomirs further showed differential expression of genes that are associated with embryo hatching and implantation.In summary,tDR-14:32-Glu-CTC-1 is up-regulated in non-blastocyst embryos and their secretions,and inhibition of tDR-14:32-Glu-CTC-1 promotes embryo hatching,while influencing embryo implantation-related genes and pathways.These results indicate that embryonic EVs containing specific tRFs may regulate preimplantation embryo development.
基金Supported by Western Project of National Social Science Fund of China(23XJY013)Project of Social Science Foundation of Shaanxi Province(2022D032).
文摘With the rapid growth of the global digital economy, cross-border e-commerce, as an emerging form of trade, has gradually become a powerful engine to promote the development of global trade. BRICS is an important force in the global economy, and the progress of the BRICS countries' trade facilitation level has an important impact on the global trade environment. This paper conducts an in-depth study of the dynamic changes in BRICS trade facilitation from 2013 to 2022, and uses an extended gravity model to analyze the specific impact of this change on China's exports using cross-border e-commerce. The results show that although the BRICS countries have made some progress in trade facilitation, the overall level still needs to be improved, and there are obvious differences among member countries. However, the improvement of trade facilitation among BRICS countries has undoubtedly brought significant positive effects to China's exports using cross-border e-commerce.
基金Key Basic Research Project of Strengthening the Foundations Plan of China (Grant No.2019-JCJQ-ZD-360-12)National Defense Basic Scientific Research Program of China (Grant No.JCKY2021208B011)to provide fund for conducting experiments。
文摘High speed photography technique is potentially the most effective way to measure the motion parameter of warhead fragment benefiting from its advantages of high accuracy,high resolution and high efficiency.However,it faces challenge in dense objects tracking and 3D trajectories reconstruction due to the characteristics of small size and dense distribution of fragment swarm.To address these challenges,this work presents a warhead fragments motion trajectories tracking and spatio-temporal distribution reconstruction method based on high-speed stereo photography.Firstly,background difference algorithm is utilized to extract the center and area of each fragment in the image sequence.Subsequently,a multi-object tracking(MOT)algorithm using Kalman filtering and Hungarian optimal assignment is developed to realize real-time and robust trajectories tracking of fragment swarm.To reconstruct 3D motion trajectories,a global stereo trajectories matching strategy is presented,which takes advantages of epipolar constraint and continuity constraint to correctly retrieve stereo correspondence followed by 3D trajectories refinement using polynomial fitting.Finally,the simulation and experimental results demonstrate that the proposed method can accurately track the motion trajectories and reconstruct the spatio-temporal distribution of 1.0×10^(3)fragments in a field of view(FOV)of 3.2 m×2.5 m,and the accuracy of the velocity estimation can achieve 98.6%.
基金supported by National Natural Science Foundation of China(Grant No.62073256)the Shaanxi Provincial Science and Technology Department(Grant No.2023-YBGY-342).
文摘To solve the problem of target damage assessment when fragments attack target under uncertain projectile and target intersection in an air defense intercept,this paper proposes a method for calculating target damage probability leveraging spatio-temporal finite multilayer fragments distribution and the target damage assessment algorithm based on cloud model theory.Drawing on the spatial dispersion characteristics of fragments of projectile proximity explosion,we divide into a finite number of fragments distribution planes based on the time series in space,set up a fragment layer dispersion model grounded in the time series and intersection criterion for determining the effective penetration of each layer of fragments into the target.Building on the precondition that the multilayer fragments of the time series effectively assail the target,we also establish the damage criterion of the perforation and penetration damage and deduce the damage probability calculation model.Taking the damage probability of the fragment layer in the spatio-temporal sequence to the target as the input state variable,we introduce cloud model theory to research the target damage assessment method.Combining the equivalent simulation experiment,the scientific and rational nature of the proposed method were validated through quantitative calculations and comparative analysis.
基金supported by the National Natural Science Foundation of China(Grant No.11872121)。
文摘The double casing warhead with sandwiched charge is a novel fragmentation warhead that can produce two groups of fragments with different velocity,and the previous work has presented a calculation formula to determine the maximum fragment velocity.The current work builds on the published formula to further develop a formula for calculating the axial distribution characteristics of the fragment velocity.For this type of warhead,the simulation of the dispersion characteristics of the detonation products at different positions shows that the detonation products at the ends have a much larger axial velocity than those in the middle,and the detonation products have a greater axial dispersion velocity when they are closer to the central axis.The loading process and the fragment velocity vary with the axial position for both casing layers,and the total velocity of the fragments is the vector sum of the radial velocity and the axial velocity.At the same axial position,the acceleration time of the inner casing is greater than that of the outer casing.For the same casing,the fragments generated at the ends have a longer acceleration time than the fragments from the middle.The proposed formula is validated with the X-ray radiography results of the four warheads previously tested experimentally and the 3D smoothedparticle hydrodynamics numerical simulation results of several series of new warheads with different configurations.The formula can accurately and reliably calculate the fragment velocity when the lengthto-diameter ratio of the charge is greater than 1.5 and the thickness of the casing is less than 20%its inner radius.This work thus provides a key reference for the theoretical analysis and the design of warheads with multiple casings.
文摘This study delves into the bilateral relations between Iran and Turkmenistan,focusing on the multidimensional impacts of cross-border ethnic groups,cultural diplomacy,and energy cooperation.The research reveals that despite challenges in security cooperation,such as regional political ideological differences and uneven power distribution,Iran has adopted diverse strategies to enhance cultural identity,social cohesion,and promote economic cooperation.Iran actively seeks to repair relations with Turkmenistan by emphasizing shared historical and cultural backgrounds,particularly the presence of cross-border Turkmen ethnic groups.Specific measures include developing cultural tourism,organizing cultural weeks,and establishing commemorative days.In the economic sphere,the two countries have signed significant natural gas supply agreements,strengthening energy cooperation.Iranian leaders often emphasize“blood ties”and deep cultural connections in diplomatic statements,combining cultural diplomacy with practical economic cooperation.The study’s findings indicate that Iran’s initiatives have led to the reorganization of national space and social reconstruction in border regions,promoting changes in public policy.By integrating cultural identity,historical connections,and economic interests,Iran has adopted a sophisticated diplomatic approach,laying the foundation for more stable and enduring bilateral relations while contributing to regional stability and sustainable development.
文摘This paper explores the operational strategies of cross-border micro, small, and medium enterprises (MSMEs). Against the backdrop of globalization and digitalization, cross-border trade has become one of the important pathways for many MSMEs to achieve growth and competitive advantage. Firstly, the paper outlines the concept and characteristics of cross-border MSMEs, as well as the analysis of their operational environment in the context of globalization, including political, economic, social, technological, environmental, and legal factors. Secondly, the paper proposes operational strategies for cross-border MSMEs, including international market selection and positioning, cross-border marketing strategies, supply chain management, cross-border financial management, and cross-border risk management. Finally, the paper summarizes the importance of effectively implementing these strategies for cross-border MSMEs to seize international market opportunities, reduce operational risks, and enhance competitiveness and profitability.
基金financed by the National Nature Science Foundation of China (Grant Nos. 30970381,31172123)
文摘The limestone region in southwestern Guangxi contains the most typical karst landforms in the world. Due to their destruction, the original forests mainly survive in nature reserves in the form of fragmented areas. From June 2009 to September 2010 we conducted an investigation of 13 relatively isolated habitats or sites, selected from each of the 13 nature reserves in southwestern Guangxi, with the least amount of anthropological activity and the largest presence of the original vegetation, in order to study the distribution of birds on forest fragments. The distribution patterns of the birds and the factors which affect them were analyzed by using the 'BINMATNEST' software and the Spearman’s rank correlation analysis, to determine: 1) whether nested patterns of birds in the karst area of southwestern Guangxi exist or not and 2) which factors are correlated with the nested patterns and the effect of these factors on forming nested patterns. The results show that the birds had statistically significant nested patterns in the karst area and the specificity of the habitat of the birds had a significant effect on the nested patterns. We suggest possible reasons for these results, based on the characteristics of the seasonal tropical rain forests in the study area and on neutral theory. We also urgently recommend that close attention be paid to the protection of the diversity of the environment for birds in all fragmented habitats.
文摘Two acetylcholinesterase (AChE) genes cDNA fragments,Ag.acel and Ag.ace2,have been cloned from cotton aphid,Aphis gossypii Glover using degenerate primers with RT-PCR technique.Ag.acel gene cDNA fragment is of 282?bp encoding 94 amino acids,and Ag.ace2 gene cDNA fragment is of 264?bp encoding 88 amino acids.Both two putative AChE genes cDNA fragments share numerous similarities with those cloned from other insects.This is the first report of two AChE cDNA fragment sequences in the insect species,which provided the direct evidence of multiple AChE existence in insects.
基金Supported by the Fund from Sichuan Academy of Agricultural Sciences for Distinguished Young Scholars (2009QNJJ-037)a Grantfor Adventive Species Monitoring from Ministry of Agriculture~~
文摘[Objective] The study aimed at evaluating the uncertainty in measuring the construct-specific fragments of genetically modified maize MON863 by real time quantitative PCR.[Method] The content of construct-specific fragments in MON863 samples was determined by real time quantitative PCR,and then the uncertainty of measurement result was evaluated according to the sources of uncertainty like the PCR system,the data processing and the micropipette.[Result] Type A evaluation of uncertainty(uA) in the measurement was 1.7×10^-2;Type B evaluation of uncertainty(uB) was 9.0×10^-4;the combined standard uncertainty(uC) was 1.7×10^-2;the expanded uncertainty(U95) was 0.036 and the finally measured result was 1.08%±0.036.[Conclusion] The main uncertainty of the result measured by real time quantitative PCR came from the randomizing effect in the experimental process.
基金Supported by the National Natural Science Foundation of China (39925007)the High Technology Research and Development Program of China (2002AA60l021)the Knowledge Innovation Program Key Project of Chinese Academy of Sciences (KSCX2-SW-102)
文摘In this paper, sinking and growth of apexes and mid-stems of Myriophyllum spicatum L., Hydrilla verticillata (L.f.) Royle and Ceratophyllum demersum L. in concrete ponds containing eutrophic water and sediment were investigated. Sinking rates of apexes and mid-stems reached 34.8% and 4.4% at the 6 th day and 91.1% and 66.7% at the 22 nd day for M. spicatum, 57.8% and 55.6% at the 6 th day and 100% and 97.8% at the 22 nd day for H. vertieillata, 18.9% and 86.7% at the 6 th day and 95.6% and 100% at the 22 nd day for C. demersum, respectively. Most sunken fragments established themselves successfully with significant growth. Total shoot length ofplantlets developed from apexes and mid-stems increased by 399% and 61% for M. spicatum, 593% and 256% for H. vertieillata and 114% and 104% for C. demersum, respectively. The results showed that it was feasible to establish submersed macrophytes via sinking and colonization of shoot fragments clipped off manually.
基金the National Basic Research Program of China (No.2006CB202200)the Creative Team Development Project of the Ministry of Education of China (No.IRT0656)
文摘Fractures running along a plane reflect the cracking progress.In this paper uniaxial and rockburst tests on a group of granite specimens from Sanya province are described.Scanning electron microscopic imaging was used to characterize the fragments.Fractal fracture mechanics were used to analyze the microcracks in terms of both the crack type and the mineral constituent.A statistical analysis showed that the area of inter-granular cracking exceeds that of intra-granular cracking.Several types of crack were observed in the cracked areas.The percentage of intra-granular cracks in fragments from rockburst tests exceeds that from uniaxial compression tests.The results also showed that feldspar deformation was the main cause of fracture and that the consolidation along quartz grain boundaries was another weak area in the granite.Cracking along quartz grains had enough energy to enter the quartz crystal in the rockburst samples.All these results contribute to further research on rockburst mechanics.
文摘Transposable elements have been utilized as mutagens to create mutant libraries for functional genomics. Isolation of genomic segments flanking the insertion Mutator (Mu) is a key step in insertion mutagenesis studies. Herein, we adopted a modified AFLP method to identify and isolate Mu-flanking fragments from maize. The method consists of the following steps: 1) double-digestion of genomic DNA with Bgl II/Msp I and ligation of digested fragments to the Bgl II- and Msp I-adaptors; 2) enrichment of a subset of Bgl II/Msp I fragments followed by selective amplification of the Mu-flanking fragments; 3) simultaneous display of AFLP bands derived from the flanking regions for both insert and native Mu transposons; 4) identification and isolation of AFLP bands resulting from Mu insertions by comparing the banding profiles between Mu-induced mutants and their parental lines; and 5) confirmation of flanking fragments related to these Mu insertions. Using this approach, we have isolated flanking fragment(s) resulting from Mu insertion for every Mu-induced mutant, and one such fragment, M196-FF, is found to contain a partial sequence of the DNA topoisomerase I gene Topl. Moreover, the modified AFLP method including all restriction enzymes, adaptors and primers has been optimized in this study. The modified AFLP method has been proved to be simple and efficient in the isolation of Mu-flanking fragments and will find its usefulness in the functional genomics of maize.
文摘3 degrees of freedom(DOF)exterior ballistic computer models are used in fragment studies to calculate individual trajectories of each fragment based on drag coefficient and the projected(presented)area in the direction of velocity of center of mass.The expectation of a randomly distributed projected area is commonly used for fragments that tumble(random rotation)during flight.We forecast a model where the expected drag coefficient is dependent of shape and Mach number.Rotation or tumbling only affects the expected projected area.Models of projected areas during tumbling and rotation are presented.An examination of the data by Mc Cleskey(1988)indicates that the volume of the fragment to the power of2/3 is a better parameter to characterize the drag coefficient of the fragments than the maximum projected area.Hydrocode simulations are used to verify results and to study projected area and drag coefficient of fragments.
文摘AIM: To investigate the state of the art regarding Cartilage Autograft Implantation System(CAIS) or Particulated Juvenile Allograft Cartilage(PJAC).METHODS: The authors searched the English literature regarding CAIS and PJAC. The search strategy was:(particulated cartilage) OR autologous cartilage fragments. All basic science articles were included. Clinical articles with less than 10 patients treated and less than 6 mo of follow-up were excluded. With these criteria, a total of 17 articles were available for the present review. RESULTS: PJAC and CAIS are relatively novel techniques for cartilage repair. Good basic science evidence was described to support the concept. Although the preliminary clinical reports show encouraging results, clinical data are still limited, especially for CAIS. The indications for both techniques need to be precisely defined(age of the patients, size of the lesion, and involvement of the subchondral bone), together with other debated issues. CONCLUSION: In conclusion, the authors can state that encouraging preliminary results are available for both techniques. However, further studies are necessary to precisely determine the indications, surgical techniques, and long term outcomes for PJAC and CAIS.
文摘AIM: To evaluate the outcomes of "concurrent vitrectomy" to retrieve dislocated lens fragment during phacoemulsification.METHODS: In a retrospective, observational case series, data of patients who underwent "concurrent" pars plana vitrectomy(PPV) for dislocated lens fragments between the period 2000 and 2008 were reviewed. Data collected included patient demographics, pre-operative visual acuity, intra-operative occurrence of retinal breaks, duration of follow up, post-operative intraocular pressure, final best-corrected visual acuity(BCVA),presence of cystoid macular edema(CME) and occurrence of rhegmatogenous retinal detachment(RRD).· RESULTS: A total of 58 eyes of 58 patients were included in the study. At 12 mo the mean postoperative BCVA was log MAR 0.17(20/30) with a range of log MAR0 to 0.69(20/20 to 20/100), with 96.6%(56/58) of patients showing post- operative improvement in visual acuity(P =0.005). None of the patients developed postoperative retinal detachment, endophthalmitis or non-resolving uveitis at 12 mo.CONCLUSION: Our study results suggest concurrent PPV for retained lens fragments after cataract surgery is beneficial and may decrease the risk of glaucoma and prevent development of RRD.
文摘The essence and the main contribution of this paper are consisted of the suggested novel method for estimation of a projected surface area of an irregularly shaped fragment, which represents a significant step toward a new method of an aerodynamic force estimation of a fragment motion through a resistive medium. The suggested method is to use a tri-axial ellipsoid that has a continuous surface(given as a mathematical function) to approximate an irregularly shaped fragment so that the fragment trajectory can be estimated faster taking into consideration that the aerodynamic force is proportional to a projected surface area of the fragment.During their motion, fragments can take any orientation relative to the velocity vector and aerodynamic force is proportional to a projected surface area of fragment perpendicular to the velocity vector,so it is necessary to have a method for correct estimation of the projected area in an arbitrary direction relatively to the fragment.The model was validated with analytical and CAD techniques, and verified using 3D model of a real fragment. The comparison of the projected surface area values for the fragment, obtained using the CAD tools and using our model, are generally in good agreement, This method represents a step toward modeling that does not require a CFD result for estimation of the aerodynamic force of irregularly shaped bodies.
文摘Probiotical cell fragments (PCFs) are structural components of the probiotic cell lysate(s) and exhibit similar beneficial effects on the host as live probiotic bacteria. With cell fragment technology (CFT?), the structural fragments are isolated and purified from live probiotic cells. While observed to be strain-dependent as in the case of live probiotics, orally administered PCFs demonstrated a broad spectrum of immune modulation functions;anti-allergy;anti-inflammation;anti-bacterial and anti-viral properties;anti-mutagenic;and radioprotective and detoxification abilities in humans and animals. The PCFs mechanisms of action include events of motifs of cell wall peptidoglycans, DNA motifs, nucleotide containing components, lipoteichoic acids (LPAs), surface layer (S-layer) proteins, and cytoplasmic proteins. Different immunological in vivo-in vitro tests have shown that PCFs, essentially, have the ability to stimulate the macrophages, and induce cytokines such as interleukins, tumor necrosis factors (TNFs), interferons (IFNs), and natural killer (NK) cells. PCFs may be used as ingredients for foods and beverages or as nutritional supplements with long term stability and shelf-life up to 5 years. PCFs may also be used as health restorative ingredients in cosmetic products. The outcome of probiotics CFT? stands as an advantage to the food and pharmaceutical industries, regarding the formulation of novel products with unadulterated sensory characteristics of origin. Hence, PCFs are being characterized here as “novel nutraceutical ingredients” for health maintenance in both humans and animals.
基金supported by the National Natural Science Foundation of China(Nos.11875323,11705163,11790320,11790323,and11961141003)the National Key R&D Program of China(No.2018YFA0404404)+1 种基金the Continuous Basic Scientific Research Project(Nos.WDJC-2019-13,BJ20002501)funding from the China Institute of Atomic Energy and the Leading Innovation Project of CNNC(Nos.LC192209000701 and LC202309000201)。
文摘In this study,we investigated the isospin properties of intermediate mass fragments(IMFs)for the central collisions of^(112,124)Sn+^(112,124)Sn at a beam energy of50 MeV per nucleon using an improved quantum molecular dynamics model(ImQMD)coupled with a sequential decay model(GEMINI).Three observables were analyzed:(1)the average center-of-mass kinetic energy per nucleon<Ec.m./A>of fragments as a function of their charge number Z;(2)the average neutron number to proton number ratio(<N>/Z)of fragments with a given charge number Z as a function of their center-of-mass kinetic energy per nucleon(Ec.m./A);and(3)the average total neutron number to total proton number ratio(ΣN/ΣZ)and double ratio(DR(N/Z))of IMFs with Z=3-8 as a function of their center-of-mass kinetic energy per nucleon Ec.m./A.Our calculations revealed that the sensitivity of the isospin properties of IMFs relative to the stiffness of the symmetry energy remains even after sequential decay.By comparing the calculations ofΣN/ΣZ and DR(N/Z)with the data,it was found that the soft symmetry energy,i.e.,γ=0.5,is favored.
文摘A warhead with axial forward projection fragments is one of the most important forms of aimable warheads. For such warheads the axial forward projection fragments are placed at the end of the explosive charge and form a fragment beam with high fragment density and high speed by the blast, which will obviously increase the damage to the targets. Experimental data showed that the velocities of the forward projection fragments on the convex end of a warhead which was initiated at the opposite end do not match that predicted by the Gurney equation for cylindrical warheads. A new approach for addressing the velocities of fragments of this kind of warhead is proposed. Two limiting conditions are defined, i.e. for fragment on the circumference of a cylindrical charge and fragments on the end of cylindrical charge, respectively.