The moving morphable component(MMC)topology optimization method,as a typical explicit topology optimization method,has been widely concerned.In the MMC topology optimization framework,the surrogate material model is m...The moving morphable component(MMC)topology optimization method,as a typical explicit topology optimization method,has been widely concerned.In the MMC topology optimization framework,the surrogate material model is mainly used for finite element analysis at present,and the effectiveness of the surrogate material model has been fully confirmed.However,there are some accuracy problems when dealing with boundary elements using the surrogate material model,which will affect the topology optimization results.In this study,a boundary element reconstruction(BER)model is proposed based on the surrogate material model under the MMC topology optimization framework to improve the accuracy of topology optimization.The proposed BER model can reconstruct the boundary elements by refining the local meshes and obtaining new nodes in boundary elements.Then the density of boundary elements is recalculated using the new node information,which is more accurate than the original model.Based on the new density of boundary elements,the material properties and volume information of the boundary elements are updated.Compared with other finite element analysis methods,the BER model is simple and feasible and can improve computational accuracy.Finally,the effectiveness and superiority of the proposed method are verified by comparing it with the optimization results of the original surrogate material model through several numerical examples.展开更多
We proposed an enhanced Reach Extender (RE) called Active Co-existence (ACEX) and investigate its performance with respect to XGS-PON system that co-exist with GPON and TWDM-PON system. The RE is consists of hybrid op...We proposed an enhanced Reach Extender (RE) called Active Co-existence (ACEX) and investigate its performance with respect to XGS-PON system that co-exist with GPON and TWDM-PON system. The RE is consists of hybrid optical amplifier integrated (EDFA and SOA) with Co-existence Element (CEX) module which is installed at the Central Office (CO) together with the OLT system and act as a booster and pre-amplifier for the downstream and upstream optical signal respectively. The results show that the proposed ACEX is capable to support XGS-PON operation for a maximum distance of 35 km with 128 splitting ratio and up to 44 dB link loss.展开更多
The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evo...The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species.A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species'ecological role.Here we investigated the interactions among environmental factors,species diversity,and the within-species genetic diversity of species with different ecological roles.Using high-throughput DNA sequencing,we genotyped a canopydominant tree species,Parashorea chinensis,and an understory-abundant species,Pittosporopsis kerrii,from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive,neutral and total genetic diversity;we also surveyed species diversity and assayed key soil nutrients.Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa.chinensis.The increased adaptive genetic diversity of Pa.chinensis led to greater species diversity by promoting co-existence.Increased species diversity reduced the adaptive genetic diversity of the dominant understory species,Pi.kerrii,which was promoted by the adaptive genetic diversity of the canopy-dominant Pa.chinensis.However,such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model.Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity,but the pattern of the interaction depends on the identity of the species.Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.展开更多
Surface epithelial-stromal tumors are the most common neoplasm of ovary in the reproductive age and beyond. Less than 1% of epithelial ovarian tumors occur before the age of 21 years while 75% of sexcord stromal tumor...Surface epithelial-stromal tumors are the most common neoplasm of ovary in the reproductive age and beyond. Less than 1% of epithelial ovarian tumors occur before the age of 21 years while 75% of sexcord stromal tumors (Sertoli and Leydig Cell) occur in the third and fourth decades of life. Serous tumors rarely occur in combination with germ cell tumors, sex-cord stromal tumors or granulosa cell tumors. Thus it is extremely rare for a combination of the above two tumors to occur before 21 years although a case report for a tumor with epithelial, stromal and sex-cord stromal elements for a 58-year-old patient has been documented. We believe ours is the first case in literature of a massive Serous Cystadenoma with co-existing stromal tumor with minor sex-cord stromal (Sertoli-Leydig Cell) elements.展开更多
The prey-seeking behavior of three spiders (X1-Pirata subpiraticus, X2-Clubiona japonicola and X3-Tetragnatha japonica) for brown plant hopper (X4-Nilaparvata lugens) and rice spittle bug (X5-Cal-litettix versicolor) ...The prey-seeking behavior of three spiders (X1-Pirata subpiraticus, X2-Clubiona japonicola and X3-Tetragnatha japonica) for brown plant hopper (X4-Nilaparvata lugens) and rice spittle bug (X5-Cal-litettix versicolor) was investigated, as well as how interference between and within species occurred, by using a quadratic regression rotational composite design. Six predation models derived from the analysis of interactions among and within predators and preys were developed. The total predatory capacity of spiders on rice insect pests after coexistence for one day can be expressed as follows: Y3 = 32.795 + 2.25X1 + 1.083X2 + 0.5X3 + 10.167X4 + 3.167X5 - 1.67X12 - 2.42X22 - 3.295X32 - 0.045X42 + 0.455X52 - 3.125X1X2 + 0.375X1X3 -0.625X1X4 - 0.375X1X5 + 0.375X2X3 - 0.875X2X4 + 0.125X2X5 + 0.375X3X4 - 0.375X3X5 + 0.125X4X5. The principal efficiency analysis using this model indicated that increases in insect pest density significantly increased predation by predators; this was much greater than the effect of any single predator. X4 had a greater effect than X5; however, X4 and X5 demonstrated little interspecific interference and even promoted each other and increased predation rates as the densities of the two pests increased. Among the three predators, an increase in the density of X, had the greatest effect on the increase in predation, X3 had the second, X2 the third greatest effect. As predator density increased inter- and intra-species interference occurred, which were largely related to the size, activity, niche breadth, niche overlap and searching efficiency of the predators. X2 produced the greatest interference between different individuals and between any other predator species. X3 had the second greatest, which reduced predation levels at high predator densities. Because of these factors, the highest predation rate was obtained at a prey density of 120 per 4 rice-hills. The optimal proportion of the three predators in the multi-predator prey system was X1: X2: X3 = 5.6:1.3:4.1.展开更多
Afrikan narratives such as folktales,proverbs and taboos were clear systems and structures on which societies operated.These were used to guide society’s values that promoted trust,accountability,self respect and man...Afrikan narratives such as folktales,proverbs and taboos were clear systems and structures on which societies operated.These were used to guide society’s values that promoted trust,accountability,self respect and many more for the wellbeing of the entire community.This paper discussesone of the Banyankole folktale Kanzanise empimba za Nzima atarikimanya akangaya(Let me stand in the gap of my sister(Nzima)while she is away or else,I will be shamed in case she knows I did not).The purpose of the paper is to demonstrate how Afrikan indigenous knowledge and specifically this folktale Kanzanise empimba za Nzima atarikimanya akangaya inculcated in the community a spirit of care,commitment to one another and transparency which are fundamental values that create peaceful societies.The paper argues that there is a wealth of wisdom residing in the African cultures to be exploited to guide African policy development.This will raise African indigenous knowledge to a platform worth recognition for its contribution towards positive transformation.Furthermore,that the Western systems and structures currently guiding Afrikan policy development are oblivious of the richness of Afrikan indigenous knowledge that united the people.The paper concludes that for Afrikans to contribute to the global agenda,they need to bring to the table of globalization a unique product such as the Afrikan indigenous narratives that contribues to world peace.The paper recommends moving back into our past,identify and promote those unique Afrikan values that sustained Africa before the Western influence.展开更多
A brain tumor associated with an arteriovenous malformation (AVM) is very rare. A 42-year-old female presented with two separate lesions in her right frontal lobe on MRI. An angiogram diagnosed one of the lesions as a...A brain tumor associated with an arteriovenous malformation (AVM) is very rare. A 42-year-old female presented with two separate lesions in her right frontal lobe on MRI. An angiogram diagnosed one of the lesions as an AVM. The second lesion appeared to be a tumor. Tumor removal was difficult due to bleeding from the nearby AVM, necessitating removal of the AVM and allowing complete excision of the tumor. Histopathological analysis revealed the tumor was an anaplastic oligodendroglioma. There was no recurrence of the tumor 5 year after completion of therapy. We discuss the operative strategy in case of synchronous diseases and provide a review of the literature.展开更多
Situated within the Cross River State of Nigeria, the Upper Cross River area covers the northern half of Cross River State comprising Ugep, Obubra, Ikom, Ogoja, and Obudu divisions. Bounded on the north by the Benue r...Situated within the Cross River State of Nigeria, the Upper Cross River area covers the northern half of Cross River State comprising Ugep, Obubra, Ikom, Ogoja, and Obudu divisions. Bounded on the north by the Benue region, west by Ebonyi and Enugu states and east by the Republic of Cameroon, this unique area experienced colonial rule. Christianity established its dominance in this area during colonial times, leaving no room for Islam. However, following the 1967 to 1970 civil war, groups of Islamic traders, clerics, and businessmen started trickling into the area, and settling there. They began to spread their faith in the region hut could not establish their political presence there. Some familiarised themselves with the culture of the indigenous people, and won converts not by force, but via the proselytisation of their faith. Community leaders did not abandon the old verities which bound traditional society in the region together. The pattern was often a pragmatic choice--accepting the best of the faiths resulting in peaceful co-existence and assured social harmony in the region. Pockets of Islamic converts could be found in Ogoja, Obudu, and some strategic commercial locations in the region. Against this backdrop, the paper examines the co-existence of Islam in the Upper Cross River Region （UCRR） and the impact made economically, culturally and religiously on the peoples of the region. The research adopted secondary and primary sources of information in its methodology. It therefore established that the UCRR of Nigeria serves as an excellent example, or a convenient model for the study of mutual religious co-existence between adherents of the Islamic and other faiths in the region.展开更多
To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fract...To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fractures,this study considered the combined impact of geological-engineering factors on conductivity.Using reservoir production parameters and the discrete elementmethod,multispherical proppants were constructed.Additionally,a 3D fracture model,based on the specified conditions of the L block,employed coupled(Computational Fluid Dynamics)CFD-DEM(Discrete ElementMethod)for joint simulations to quantitatively analyze the transport and placement patterns of multispherical proppants in intersecting fractures.Results indicate that turbulent kinetic energy is an intrinsic factor affecting proppant transport.Moreover,the efficiency of placement and migration distance of low-sphericity quartz sand constructed by the DEM in the main fracture are significantly reduced compared to spherical ceramic proppants,with a 27.7%decrease in the volume fraction of the fracture surface,subsequently affecting the placement concentration and damaging fracture conductivity.Compared to small-angle fractures,controlling artificial and natural fractures to expand at angles of 45°to 60°increases the effective support length by approximately 20.6%.During hydraulic fracturing of gas wells,ensuring the fracture support area and post-closure conductivity can be achieved by controlling the sphericity of proppants and adjusting the perforation direction to control the direction of artificial fractures.展开更多
Neurodegenerative diseases cause great medical and economic burdens for both patients and society;however, the complex molecular mechanisms thereof are not yet well understood. With the development of high-coverage se...Neurodegenerative diseases cause great medical and economic burdens for both patients and society;however, the complex molecular mechanisms thereof are not yet well understood. With the development of high-coverage sequencing technology, researchers have started to notice that genomic repeat regions, previously neglected in search of disease culprits, are active contributors to multiple neurodegenerative diseases. In this review, we describe the association between repeat element variants and multiple degenerative diseases through genome-wide association studies and targeted sequencing. We discuss the identification of disease-relevant repeat element variants, further powered by the advancement of long-read sequencing technologies and their related tools, and summarize recent findings in the molecular mechanisms of repeat element variants in brain degeneration, such as those causing transcriptional silencing or RNA-mediated gain of toxic function. Furthermore, we describe how in silico predictions using innovative computational models, such as deep learning language models, could enhance and accelerate our understanding of the functional impact of repeat element variants. Finally, we discuss future directions to advance current findings for a better understanding of neurodegenerative diseases and the clinical applications of genomic repeat elements.展开更多
THE premiere of popular Chinese TV soapie Beijing Love Storywas widely hailed as a major cultural breakthrough in the Nigerian capital of Abuja on September 18. Dubbed into Hausa. one of Nigeria＇s major languages, th...THE premiere of popular Chinese TV soapie Beijing Love Storywas widely hailed as a major cultural breakthrough in the Nigerian capital of Abuja on September 18. Dubbed into Hausa. one of Nigeria＇s major languages, the drama formed part of the Experience China program held by China＇s State Council Information Office （SCIO） in Abuja from September 10 to 19.展开更多
Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However...Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.展开更多
As a new type of production factor in healthcare,healthcare data elements have been rapidly integrated into various health production processes,such as clinical assistance,health management,biological testing,and oper...As a new type of production factor in healthcare,healthcare data elements have been rapidly integrated into various health production processes,such as clinical assistance,health management,biological testing,and operation and supervision[1,2].Healthcare data elements include biolog.ical and clinical data that are related to disease,environ-mental health data that are associated with life,and operational and healthcare management data that are related to healthcare activities(Figure 1).Activities such as the construction of a data value assessment system,the devel-opment of a data circulation and sharing platform,and the authorization of data compliance and operation products support the strong growth momentum of the market for health care data elements in China[3].展开更多
Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.展开更多
In this paper,potent index of an element and pseudo clean rings are considered.Some properties and examples of pseudo clean rings are given.We also show that Zm is pseudo clean for every 2≤m∈Z and pseudo clean rings...In this paper,potent index of an element and pseudo clean rings are considered.Some properties and examples of pseudo clean rings are given.We also show that Zm is pseudo clean for every 2≤m∈Z and pseudo clean rings are clean.Furthermore,we prove pseudo clean rings are directly finite and have stable range one.展开更多
The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the ...The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.展开更多
Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical compositi...Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical composition of the film surface was determined using surface characterization techniques.The corrosion resistance of the films was characterized using electrochemical impedance spectroscopy,potentiodynamic polarization,and scanning Kelvin probe microscopy at multiple scales.The thermal stability,mechanical stability,and self-cleaning properties of the films were also characterized.It was determined that the Cu–Co–Ni superhydrophobic film exhibited the best performance,with a static water contact angle of 159.3°,a roll-off angle of 2.3°,a charge transfer resistance 3300 times higher than the substrate,a self-corrosion current density nearly three orders of magnitude lower,and a surface Kelvin potential increase of 420 mV.The film demonstrated good thermal stability,excellent mechanical stability,and outstanding self-cleaning properties.Combining with previous studies,it was found that Co elements in the film contribute to the formation of a uniform and dense film,Ni elements enhance the adhesion and corrosion resistance between the films,and the combination of Co and Ni elements promotes uniform surface potential and further improves the corrosion resistance and interfilm adhesion of the films.展开更多
This work focused on determining the physico-chemical characteristics (pH, carbon and nitrogen) and trace metal elements (TMEs) content (As, Sb, Cd, Hg, Ni, Pb, Cr, Zn) of soils in the Brazzaville city. Soil samples w...This work focused on determining the physico-chemical characteristics (pH, carbon and nitrogen) and trace metal elements (TMEs) content (As, Sb, Cd, Hg, Ni, Pb, Cr, Zn) of soils in the Brazzaville city. Soil samples were taken from a depth of 0 to 20 cm using a hand auger on both banks of five tributaries of the Congo River (Djoué, Mfilou, Mfoa, Tsiémé, Djiri) that flow through the city of Brazzaville. 90 sampling points were defined, with 3 points 250 m apart on the banks and located, for each river, at three sites: upstream, midstream and downstream. Finally, 15 composite samples representative of the study area were taken. The average pH values of the water varied between 6.5 and 7.5. These pH values show that the soils studied are neutral. Total carbon content varied between 0.7% (Djiri) and 1.6% (Djoué). Total nitrogen content ranged from 0.08% (Djiri) to 0.12% (Djoué). TMEs contents varied from 0.5 to 1.8 mg/kg for Sb, from 0.5 to 2.5 mg/kg for As, from 0.1 to 0.18 mg/kg for Cd, from 4.2 to 11.3 mg/kg for Cr, from 0.07 to 0.27 mg/kg for Hg, from 0.7 to 2.4 mg/kg for Ni, from 0 to 158 mg/kg for Pb and from 16 to 105 mg/kg for Zn. The lowest TMEs levels were observed in the soils of the Djiri river, while the highest levels were observed in the soils of the Djoué and Tsiémé rivers. The ANOVA and Bonferroni test did not show significant differences in the means of the parameters measured (p > 0.05). The TMEs levels were below the accepted standards (NF U44-041), with the exception of Pb, which had high levels downstream of the Djoué. According to the pollution index values calculated using soil TME content, the soils on the banks of the Djoué river are considered polluted, while those on the banks of the Tsiémé river are moderately polluted, those on the banks of the Mfoa and Mfilou rivers are slightly polluted, and the soils on the banks of Djiri river are unpolluted.展开更多
The presence of inorganic constituents in coal is controlled by different geological factors,which,in turn,affect the technological,environmental,and health impacts of the coal.The main aim of this study is to objecti...The presence of inorganic constituents in coal is controlled by different geological factors,which,in turn,affect the technological,environmental,and health impacts of the coal.The main aim of this study is to objectively assess the mineralogical and geochemical characteristics of a thickest low-rank coal seam in the Lower Indus Basin southeastern Pakistan,and further investigate different controlling factors.The analytical results of major oxides,trace elements,and rare earth elements revealed that the weathering conditions were progressively variable and moderate.The sediment source,mainly of felsic and intermediate composition,was dominated by granitic rocks.The geochemical assessment reveals different depositional factors like marine environment influenced,while transitional and freshwater sediments influenced the center of the coal peat mire.Strontium,Zinc,and several hazardous trace elements,including Cu,Ni,Cr,and Co,have higher concentrations in these coals compared to world low-rank,U.S.,and Chinese coals.The relatively higher concentration of Sr in the thick coal seam in the Lower Indus Basin,compared to other coals seams in Pakistan and the enrichment of Sr was primarily controlled by the denudation of crystalline rocks and marine influx in the coal-basin.The REY distribution pattern showed that enrichment of medium and heavy rare earth elements is higher than light rare earth elements in the coal seam.The Gd distribution pattern in the coal seam demonstrated that strong positive anomalies had a good affinity with paleo-acidic water concentration in the study area.The higher concentration of Sr and other elements enables a better assessment understanding of the coal geochemical history.展开更多
Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intak...Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intake fails to compensate. The aim of this research is to determine the status of trace elements (calcium, copper, magnesium, selenium and zinc) in pregnant women in the city of Kisangani. Methods: We carried out an analytical cross-sectional study of non-pregnant and pregnant women living in Kisangani, from 05 October 2023 to 05 January 2024. Concentrations of trace elements in sera were analysed using an inductively coupled plasma mass spectrophotometer (ICP-MS Agilent 7700X). Statistical analysis of the data was performed using R software version 4.3.0. Results: The mean age was 26.3 ± 6.7 years;the mean copper and magnesium levels in the serum of pregnant women were 12.58 ± 1.13 micromol/l and 1.03 ± 1.03 mmol/l respectively. The medians for calcium and zinc were 1.49 mmol/l and 8.42 micromol/l. The selenium mode was 0.41 micromol/l. Variations in trace element levels in sera of pregnant women were 0.94 - 2.22 mmol/l for calcium;0.31 - 0.78 micromol/l for selenium;and 7.29 - 12.72 micromol/l for zinc;11.04 - 14.99 micromol/l for copper, and 0.082 - 1.05 mmol/l for magnesium. Conclusion: Serum trace element concentrations in pregnant women were lower than those observed in non-pregnant women. Trace element reserves in pregnant women depended on their nutrient status prior to pregnancy, hence, there was an urgent need for trace element balance prior to pregnancy.展开更多
基金supported by the Science and Technology Research Project of Henan Province(242102241055)the Industry-University-Research Collaborative Innovation Base on Automobile Lightweight of“Science and Technology Innovation in Central Plains”(2024KCZY315)the Opening Fund of State Key Laboratory of Structural Analysis,Optimization and CAE Software for Industrial Equipment(GZ2024A03-ZZU).
文摘The moving morphable component(MMC)topology optimization method,as a typical explicit topology optimization method,has been widely concerned.In the MMC topology optimization framework,the surrogate material model is mainly used for finite element analysis at present,and the effectiveness of the surrogate material model has been fully confirmed.However,there are some accuracy problems when dealing with boundary elements using the surrogate material model,which will affect the topology optimization results.In this study,a boundary element reconstruction(BER)model is proposed based on the surrogate material model under the MMC topology optimization framework to improve the accuracy of topology optimization.The proposed BER model can reconstruct the boundary elements by refining the local meshes and obtaining new nodes in boundary elements.Then the density of boundary elements is recalculated using the new node information,which is more accurate than the original model.Based on the new density of boundary elements,the material properties and volume information of the boundary elements are updated.Compared with other finite element analysis methods,the BER model is simple and feasible and can improve computational accuracy.Finally,the effectiveness and superiority of the proposed method are verified by comparing it with the optimization results of the original surrogate material model through several numerical examples.
文摘We proposed an enhanced Reach Extender (RE) called Active Co-existence (ACEX) and investigate its performance with respect to XGS-PON system that co-exist with GPON and TWDM-PON system. The RE is consists of hybrid optical amplifier integrated (EDFA and SOA) with Co-existence Element (CEX) module which is installed at the Central Office (CO) together with the OLT system and act as a booster and pre-amplifier for the downstream and upstream optical signal respectively. The results show that the proposed ACEX is capable to support XGS-PON operation for a maximum distance of 35 km with 128 splitting ratio and up to 44 dB link loss.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDB31000000the National Natural Science Foundation of China(No.31370267).
文摘The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species.A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species'ecological role.Here we investigated the interactions among environmental factors,species diversity,and the within-species genetic diversity of species with different ecological roles.Using high-throughput DNA sequencing,we genotyped a canopydominant tree species,Parashorea chinensis,and an understory-abundant species,Pittosporopsis kerrii,from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive,neutral and total genetic diversity;we also surveyed species diversity and assayed key soil nutrients.Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa.chinensis.The increased adaptive genetic diversity of Pa.chinensis led to greater species diversity by promoting co-existence.Increased species diversity reduced the adaptive genetic diversity of the dominant understory species,Pi.kerrii,which was promoted by the adaptive genetic diversity of the canopy-dominant Pa.chinensis.However,such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model.Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity,but the pattern of the interaction depends on the identity of the species.Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.
文摘Surface epithelial-stromal tumors are the most common neoplasm of ovary in the reproductive age and beyond. Less than 1% of epithelial ovarian tumors occur before the age of 21 years while 75% of sexcord stromal tumors (Sertoli and Leydig Cell) occur in the third and fourth decades of life. Serous tumors rarely occur in combination with germ cell tumors, sex-cord stromal tumors or granulosa cell tumors. Thus it is extremely rare for a combination of the above two tumors to occur before 21 years although a case report for a tumor with epithelial, stromal and sex-cord stromal elements for a 58-year-old patient has been documented. We believe ours is the first case in literature of a massive Serous Cystadenoma with co-existing stromal tumor with minor sex-cord stromal (Sertoli-Leydig Cell) elements.
文摘The prey-seeking behavior of three spiders (X1-Pirata subpiraticus, X2-Clubiona japonicola and X3-Tetragnatha japonica) for brown plant hopper (X4-Nilaparvata lugens) and rice spittle bug (X5-Cal-litettix versicolor) was investigated, as well as how interference between and within species occurred, by using a quadratic regression rotational composite design. Six predation models derived from the analysis of interactions among and within predators and preys were developed. The total predatory capacity of spiders on rice insect pests after coexistence for one day can be expressed as follows: Y3 = 32.795 + 2.25X1 + 1.083X2 + 0.5X3 + 10.167X4 + 3.167X5 - 1.67X12 - 2.42X22 - 3.295X32 - 0.045X42 + 0.455X52 - 3.125X1X2 + 0.375X1X3 -0.625X1X4 - 0.375X1X5 + 0.375X2X3 - 0.875X2X4 + 0.125X2X5 + 0.375X3X4 - 0.375X3X5 + 0.125X4X5. The principal efficiency analysis using this model indicated that increases in insect pest density significantly increased predation by predators; this was much greater than the effect of any single predator. X4 had a greater effect than X5; however, X4 and X5 demonstrated little interspecific interference and even promoted each other and increased predation rates as the densities of the two pests increased. Among the three predators, an increase in the density of X, had the greatest effect on the increase in predation, X3 had the second, X2 the third greatest effect. As predator density increased inter- and intra-species interference occurred, which were largely related to the size, activity, niche breadth, niche overlap and searching efficiency of the predators. X2 produced the greatest interference between different individuals and between any other predator species. X3 had the second greatest, which reduced predation levels at high predator densities. Because of these factors, the highest predation rate was obtained at a prey density of 120 per 4 rice-hills. The optimal proportion of the three predators in the multi-predator prey system was X1: X2: X3 = 5.6:1.3:4.1.
文摘Afrikan narratives such as folktales,proverbs and taboos were clear systems and structures on which societies operated.These were used to guide society’s values that promoted trust,accountability,self respect and many more for the wellbeing of the entire community.This paper discussesone of the Banyankole folktale Kanzanise empimba za Nzima atarikimanya akangaya(Let me stand in the gap of my sister(Nzima)while she is away or else,I will be shamed in case she knows I did not).The purpose of the paper is to demonstrate how Afrikan indigenous knowledge and specifically this folktale Kanzanise empimba za Nzima atarikimanya akangaya inculcated in the community a spirit of care,commitment to one another and transparency which are fundamental values that create peaceful societies.The paper argues that there is a wealth of wisdom residing in the African cultures to be exploited to guide African policy development.This will raise African indigenous knowledge to a platform worth recognition for its contribution towards positive transformation.Furthermore,that the Western systems and structures currently guiding Afrikan policy development are oblivious of the richness of Afrikan indigenous knowledge that united the people.The paper concludes that for Afrikans to contribute to the global agenda,they need to bring to the table of globalization a unique product such as the Afrikan indigenous narratives that contribues to world peace.The paper recommends moving back into our past,identify and promote those unique Afrikan values that sustained Africa before the Western influence.
文摘A brain tumor associated with an arteriovenous malformation (AVM) is very rare. A 42-year-old female presented with two separate lesions in her right frontal lobe on MRI. An angiogram diagnosed one of the lesions as an AVM. The second lesion appeared to be a tumor. Tumor removal was difficult due to bleeding from the nearby AVM, necessitating removal of the AVM and allowing complete excision of the tumor. Histopathological analysis revealed the tumor was an anaplastic oligodendroglioma. There was no recurrence of the tumor 5 year after completion of therapy. We discuss the operative strategy in case of synchronous diseases and provide a review of the literature.
文摘Situated within the Cross River State of Nigeria, the Upper Cross River area covers the northern half of Cross River State comprising Ugep, Obubra, Ikom, Ogoja, and Obudu divisions. Bounded on the north by the Benue region, west by Ebonyi and Enugu states and east by the Republic of Cameroon, this unique area experienced colonial rule. Christianity established its dominance in this area during colonial times, leaving no room for Islam. However, following the 1967 to 1970 civil war, groups of Islamic traders, clerics, and businessmen started trickling into the area, and settling there. They began to spread their faith in the region hut could not establish their political presence there. Some familiarised themselves with the culture of the indigenous people, and won converts not by force, but via the proselytisation of their faith. Community leaders did not abandon the old verities which bound traditional society in the region together. The pattern was often a pragmatic choice--accepting the best of the faiths resulting in peaceful co-existence and assured social harmony in the region. Pockets of Islamic converts could be found in Ogoja, Obudu, and some strategic commercial locations in the region. Against this backdrop, the paper examines the co-existence of Islam in the Upper Cross River Region （UCRR） and the impact made economically, culturally and religiously on the peoples of the region. The research adopted secondary and primary sources of information in its methodology. It therefore established that the UCRR of Nigeria serves as an excellent example, or a convenient model for the study of mutual religious co-existence between adherents of the Islamic and other faiths in the region.
基金funded by the project of the Major Scientific and Technological Projects of CNOOC in the 14th Five-Year Plan(No.KJGG2022-0701)the CNOOC Research Institute(No.2020PFS-03).
文摘To analyze the differences in the transport and distribution of different types of proppants and to address issues such as the short effective support of proppant and poor placement in hydraulically intersecting fractures,this study considered the combined impact of geological-engineering factors on conductivity.Using reservoir production parameters and the discrete elementmethod,multispherical proppants were constructed.Additionally,a 3D fracture model,based on the specified conditions of the L block,employed coupled(Computational Fluid Dynamics)CFD-DEM(Discrete ElementMethod)for joint simulations to quantitatively analyze the transport and placement patterns of multispherical proppants in intersecting fractures.Results indicate that turbulent kinetic energy is an intrinsic factor affecting proppant transport.Moreover,the efficiency of placement and migration distance of low-sphericity quartz sand constructed by the DEM in the main fracture are significantly reduced compared to spherical ceramic proppants,with a 27.7%decrease in the volume fraction of the fracture surface,subsequently affecting the placement concentration and damaging fracture conductivity.Compared to small-angle fractures,controlling artificial and natural fractures to expand at angles of 45°to 60°increases the effective support length by approximately 20.6%.During hydraulic fracturing of gas wells,ensuring the fracture support area and post-closure conductivity can be achieved by controlling the sphericity of proppants and adjusting the perforation direction to control the direction of artificial fractures.
基金supported by the National Natural Science Foundation of China, No.61932008Natural Science Foundation of Shanghai, No.21ZR1403200 (both to JC)。
文摘Neurodegenerative diseases cause great medical and economic burdens for both patients and society;however, the complex molecular mechanisms thereof are not yet well understood. With the development of high-coverage sequencing technology, researchers have started to notice that genomic repeat regions, previously neglected in search of disease culprits, are active contributors to multiple neurodegenerative diseases. In this review, we describe the association between repeat element variants and multiple degenerative diseases through genome-wide association studies and targeted sequencing. We discuss the identification of disease-relevant repeat element variants, further powered by the advancement of long-read sequencing technologies and their related tools, and summarize recent findings in the molecular mechanisms of repeat element variants in brain degeneration, such as those causing transcriptional silencing or RNA-mediated gain of toxic function. Furthermore, we describe how in silico predictions using innovative computational models, such as deep learning language models, could enhance and accelerate our understanding of the functional impact of repeat element variants. Finally, we discuss future directions to advance current findings for a better understanding of neurodegenerative diseases and the clinical applications of genomic repeat elements.
文摘THE premiere of popular Chinese TV soapie Beijing Love Storywas widely hailed as a major cultural breakthrough in the Nigerian capital of Abuja on September 18. Dubbed into Hausa. one of Nigeria＇s major languages, the drama formed part of the Experience China program held by China＇s State Council Information Office （SCIO） in Abuja from September 10 to 19.
基金supports from the National Key Research and Development Program of China(2023YFB2806803)the National Natural Science Foundation of China(62075127).
文摘Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.
基金supported by National Natural Science Foundation of China(Grants 72474022,71974011,72174022,71972012,71874009)"BIT think tank"Promotion Plan of Science and Technology Innovation Program of Beijing Institute of Technology(Grants 2024CX14017,2023CX13029).
文摘As a new type of production factor in healthcare,healthcare data elements have been rapidly integrated into various health production processes,such as clinical assistance,health management,biological testing,and operation and supervision[1,2].Healthcare data elements include biolog.ical and clinical data that are related to disease,environ-mental health data that are associated with life,and operational and healthcare management data that are related to healthcare activities(Figure 1).Activities such as the construction of a data value assessment system,the devel-opment of a data circulation and sharing platform,and the authorization of data compliance and operation products support the strong growth momentum of the market for health care data elements in China[3].
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
基金Supported by National Natural Science Foundation of China(12301041)。
文摘In this paper,potent index of an element and pseudo clean rings are considered.Some properties and examples of pseudo clean rings are given.We also show that Zm is pseudo clean for every 2≤m∈Z and pseudo clean rings are clean.Furthermore,we prove pseudo clean rings are directly finite and have stable range one.
基金supported by the National Key R&D Program of China(No.2022YFB2404400)the National Natural Science Foundation of China(Nos.U23A20577,52372168,92263206 and 21975006)+1 种基金the“The Youth Beijing Scholars program”(No.PXM2021_014204_000023)the Beijing Natural Science Foundation(Nos.2222001 and KM202110005009).
文摘The cobalt-free Mn-based Li-rich layered oxide material has the advantages of low cost,high energy density,and good performance at low temperatures,and is the promising choice for energy storage batteries.However,the long-cycling stability of batteries needs to be improved.Herein,the Mn-based Li-rich cathode materials with small amounts of Li2 MnO3 crystal domains and gradient doping of Al and Ti elements from the surface to the bulk have been developed to improve the structure and interface stability.Then the batteries with a high energy density of 600 Wh kg^(-1),excellent capacity retention of 99.7%with low voltage decay of 0.03 mV cycle^(-1) after 800 cycles,and good rates performances can be achieved.Therefore,the structure and cycling stability of low voltage Mn-based Li-rich cathode materials can be significantly improved by the bulk structure design and interface regulation,and this work has paved the way for developing low-cost and high-energy Mn-based energy storage batteries with long lifetime.
基金fnancial support by the National Natural Science Foundation of China(Grant No.42176209)the Natural Science Foundation of Shandong Province(Grant No.ZR2021MD064).
文摘Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical composition of the film surface was determined using surface characterization techniques.The corrosion resistance of the films was characterized using electrochemical impedance spectroscopy,potentiodynamic polarization,and scanning Kelvin probe microscopy at multiple scales.The thermal stability,mechanical stability,and self-cleaning properties of the films were also characterized.It was determined that the Cu–Co–Ni superhydrophobic film exhibited the best performance,with a static water contact angle of 159.3°,a roll-off angle of 2.3°,a charge transfer resistance 3300 times higher than the substrate,a self-corrosion current density nearly three orders of magnitude lower,and a surface Kelvin potential increase of 420 mV.The film demonstrated good thermal stability,excellent mechanical stability,and outstanding self-cleaning properties.Combining with previous studies,it was found that Co elements in the film contribute to the formation of a uniform and dense film,Ni elements enhance the adhesion and corrosion resistance between the films,and the combination of Co and Ni elements promotes uniform surface potential and further improves the corrosion resistance and interfilm adhesion of the films.
文摘This work focused on determining the physico-chemical characteristics (pH, carbon and nitrogen) and trace metal elements (TMEs) content (As, Sb, Cd, Hg, Ni, Pb, Cr, Zn) of soils in the Brazzaville city. Soil samples were taken from a depth of 0 to 20 cm using a hand auger on both banks of five tributaries of the Congo River (Djoué, Mfilou, Mfoa, Tsiémé, Djiri) that flow through the city of Brazzaville. 90 sampling points were defined, with 3 points 250 m apart on the banks and located, for each river, at three sites: upstream, midstream and downstream. Finally, 15 composite samples representative of the study area were taken. The average pH values of the water varied between 6.5 and 7.5. These pH values show that the soils studied are neutral. Total carbon content varied between 0.7% (Djiri) and 1.6% (Djoué). Total nitrogen content ranged from 0.08% (Djiri) to 0.12% (Djoué). TMEs contents varied from 0.5 to 1.8 mg/kg for Sb, from 0.5 to 2.5 mg/kg for As, from 0.1 to 0.18 mg/kg for Cd, from 4.2 to 11.3 mg/kg for Cr, from 0.07 to 0.27 mg/kg for Hg, from 0.7 to 2.4 mg/kg for Ni, from 0 to 158 mg/kg for Pb and from 16 to 105 mg/kg for Zn. The lowest TMEs levels were observed in the soils of the Djiri river, while the highest levels were observed in the soils of the Djoué and Tsiémé rivers. The ANOVA and Bonferroni test did not show significant differences in the means of the parameters measured (p > 0.05). The TMEs levels were below the accepted standards (NF U44-041), with the exception of Pb, which had high levels downstream of the Djoué. According to the pollution index values calculated using soil TME content, the soils on the banks of the Djoué river are considered polluted, while those on the banks of the Tsiémé river are moderately polluted, those on the banks of the Mfoa and Mfilou rivers are slightly polluted, and the soils on the banks of Djiri river are unpolluted.
基金supported by the National Natural Science Foundation of China,funding numbers 41690131,41572327,51874280 and 5264015.
文摘The presence of inorganic constituents in coal is controlled by different geological factors,which,in turn,affect the technological,environmental,and health impacts of the coal.The main aim of this study is to objectively assess the mineralogical and geochemical characteristics of a thickest low-rank coal seam in the Lower Indus Basin southeastern Pakistan,and further investigate different controlling factors.The analytical results of major oxides,trace elements,and rare earth elements revealed that the weathering conditions were progressively variable and moderate.The sediment source,mainly of felsic and intermediate composition,was dominated by granitic rocks.The geochemical assessment reveals different depositional factors like marine environment influenced,while transitional and freshwater sediments influenced the center of the coal peat mire.Strontium,Zinc,and several hazardous trace elements,including Cu,Ni,Cr,and Co,have higher concentrations in these coals compared to world low-rank,U.S.,and Chinese coals.The relatively higher concentration of Sr in the thick coal seam in the Lower Indus Basin,compared to other coals seams in Pakistan and the enrichment of Sr was primarily controlled by the denudation of crystalline rocks and marine influx in the coal-basin.The REY distribution pattern showed that enrichment of medium and heavy rare earth elements is higher than light rare earth elements in the coal seam.The Gd distribution pattern in the coal seam demonstrated that strong positive anomalies had a good affinity with paleo-acidic water concentration in the study area.The higher concentration of Sr and other elements enables a better assessment understanding of the coal geochemical history.
文摘Introduction: During pregnancy, the increased demand for all the nutrients required for the development of the foetus means that the maternal stock of trace elements and minerals may become unbalanced if dietary intake fails to compensate. The aim of this research is to determine the status of trace elements (calcium, copper, magnesium, selenium and zinc) in pregnant women in the city of Kisangani. Methods: We carried out an analytical cross-sectional study of non-pregnant and pregnant women living in Kisangani, from 05 October 2023 to 05 January 2024. Concentrations of trace elements in sera were analysed using an inductively coupled plasma mass spectrophotometer (ICP-MS Agilent 7700X). Statistical analysis of the data was performed using R software version 4.3.0. Results: The mean age was 26.3 ± 6.7 years;the mean copper and magnesium levels in the serum of pregnant women were 12.58 ± 1.13 micromol/l and 1.03 ± 1.03 mmol/l respectively. The medians for calcium and zinc were 1.49 mmol/l and 8.42 micromol/l. The selenium mode was 0.41 micromol/l. Variations in trace element levels in sera of pregnant women were 0.94 - 2.22 mmol/l for calcium;0.31 - 0.78 micromol/l for selenium;and 7.29 - 12.72 micromol/l for zinc;11.04 - 14.99 micromol/l for copper, and 0.082 - 1.05 mmol/l for magnesium. Conclusion: Serum trace element concentrations in pregnant women were lower than those observed in non-pregnant women. Trace element reserves in pregnant women depended on their nutrient status prior to pregnancy, hence, there was an urgent need for trace element balance prior to pregnancy.
