The present paper deals with the induced orientational order of the probe molecules dissolved in the uniaxially strained rubbers measured by using deuterium NMR. The distinctive dependence of the quadrupolar splitting...The present paper deals with the induced orientational order of the probe molecules dissolved in the uniaxially strained rubbers measured by using deuterium NMR. The distinctive dependence of the quadrupolar splitting on the swelling, elongation and crosslinking density was observed. The orientational order arising from the correlation between chain segments decreases with the increase of the numbers of both links between junctions and solvent molecules around segments.展开更多
As a part of our systematic study of the physical properties of the compounds of symmetric liquid crystal dimer homologous series, α,ω-bis-(4-n-alkylaniline benzylidene-4’-oxy) alkanes (m.OnO.m), we report here an ...As a part of our systematic study of the physical properties of the compounds of symmetric liquid crystal dimer homologous series, α,ω-bis-(4-n-alkylaniline benzylidene-4’-oxy) alkanes (m.OnO.m), we report here an optical study of two nematogenic compounds of this series viz., 6.O12O.6 and 7.O12O.7 by carrying out the measurement of extraordinary and ordinary refractive indices using modified spectrometer. The molecular polarizability anisotropies are evaluated using Lippincott δ-function model, the molecular vibration method, Haller’s extrapolation method and scaling factor method. The molecular polrizabilities, αe and αo are calculated using Vuks’ isotropic field model and Neugebauer’s anisotropic field model. The orientational order parameter, S, is estimated by using the molecular polarizability values calculated from refractive index and denstity data as well as polarizability anisotropy values calculated as a function of temperature in the nematic phase of both of the dimers. These values are discussed with reference to the order parameter values obtained directly from the optical birefringence, Δn, data without assuming any internal field. A comparison of the order parameter values from all of these methods was carried out in the light of available literature data.展开更多
The orientational order is an important concept of the materials composed of large molecules or clusters. Using high-resolution scanning tunneling microscopy, we have studied the orientational order of two kinds of ty...The orientational order is an important concept of the materials composed of large molecules or clusters. Using high-resolution scanning tunneling microscopy, we have studied the orientational order of two kinds of typical low-dimensional C60 lattices: two-dimensional molecules array and C60(111) multi-layer film surface. Due to the change of the crystal field, their orientational orders are distinctly different from those in bulk system, and some unique phenomena appear.展开更多
New concepts such as intramolecular orientational order parameter and corresponding model as well as theory were proposed to describe the intramolecular orientation of mesogenic units in the liquid crystalline polymer...New concepts such as intramolecular orientational order parameter and corresponding model as well as theory were proposed to describe the intramolecular orientation of mesogenic units in the liquid crystalline polymer chains. The relationship between the intramolecular orientational order parameter and the molecular geometrical parameters such as the bond angle, the bond rotational angle and the rotational potential energy of chemical bonds was deduced. A significant even-odd oscillation of the intramolecular orientational order parameter of LCPs with different length of flexible spacer was found and rationally related to even-odd zig-zag manner of transition properties The verification and application of the theory are also discussed. The isotropic transition temperature predicted by the theory is shown to be in favourable agreement with the experiments.展开更多
Due to the important role ofδphase's quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components,it is necessary to renew insights into the effect of cold deformation ...Due to the important role ofδphase's quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components,it is necessary to renew insights into the effect of cold deformation on theδphase precipitation,especially on the morphology evolution.Therefore,the nucleation and growth behavior ofδphase in cold-rolled Inconel 718 alloy during aging were investigated.The results show that the precipitation rate and volume fraction ofδphase increase with increasing the cold rolling reduction from 10%to 50%.The volume fraction ofδphase reaches equilibrium after 5 h,remaining at 5.98%,6.52%,and 6.79%under different rolling reductions(10%,30%,and 50%),respectively.The nucleation ofδphase mainly occurs on different sites(grain boundaries,new twin boundaries and old twin boundaries)under 10%rolling reduction,whileδphase mainly nucleates on the new grain boundaries of static recrystallization due to 50%rolling reduction.And the growth ofδphase undergoes a process of alternate orientation growth from spherical(nucleation)→short rod(longitudinal orientation growth)→short rod(radial orientation growth)→dynamic equilib-rium.Under 10%rolling reduction,δphase tends to grow into the matrix,while under 50%rolling reduction,the orientation grows faster and is easily affected by the grain boundary curvature.展开更多
Re-innervation of sensory and motor neurons on a defined area of the body wall was studied in two species of leeches, Whitmania pigra and Hirudo medicinalis, as a model of segmental animals. Following isolation and ro...Re-innervation of sensory and motor neurons on a defined area of the body wall was studied in two species of leeches, Whitmania pigra and Hirudo medicinalis, as a model of segmental animals. Following isolation and rotation of a tube of body wall, the mechanical sensory and annular erection (AE) motor neurons re-innervated the body wall, at a rate of approximately 3. 8 -8. 4 μm/h. The patterns of re-innerva-tion by pairs of neurons on each side of a ganglion were bilaterally symmetric. The repairs are synchronous for the sensory and motor neurons which are of different functions but in a same ganglion. The gap junctions are widely spread in leech between neurons and glia cells, as well as among the neurons and glia cells themselves. Therefore, it is proposed that the nervous system repair is regulated by a low-resistance pathway. In the xenotransplantation experiments, neurons recognized target tissues before the immuno-recognition and rejection.展开更多
The integrated repair of bone and cartilage boasts advantages for osteochondral restoration such as a long-term repair effect and less deterioration compared to repairing cartilage alone.Constructing multifactorial,sp...The integrated repair of bone and cartilage boasts advantages for osteochondral restoration such as a long-term repair effect and less deterioration compared to repairing cartilage alone.Constructing multifactorial,spatially oriented scaffolds to stimulate osteochondral regeneration,has immense significance.Herein,targeted drugs,namely kartogenin@polydopamine(KGN@PDA)nanoparticles for cartilage repair and miRNA@calcium phosphate(miRNA@CaP)NPs for bone regeneration,were in situ deposited on a patterned supramolecular-assembled 2-ureido-4[lH]-pyrimidinone(UPy)modified gelation hydrogel film,facilitated by the dynamic and responsive coordination and complexation of metal ions and their ligands.This hydrogel film can be rolled into a cylindrical plug,mimicking the Haversian canal structure of natural bone.The resultant hydrogel demonstrates stable mechanical properties,a self-healing ability,a high capability for reactive oxygen species capture,and controlled release of KGN and miR-26a.In vitro,KGN@PDA and miRNA@CaP promote chondrogenic and osteogenic differentiation of mesenchymal stem cells via the JNK/RUNX1 and GSK-3β/β-catenin pathways,respectively.In vivo,the osteochondral plug exhibits optimal subchondral bone and cartilage regeneration,evidenced by a significant increase in glycosaminoglycan and collagen accumulation in specific zones,along with the successful integration of neocartilage with subchondral bone.This biomaterial delivery approach represents a significant toward improved osteochondral repair.展开更多
Based on the building principle of additive manufacturing,printing orientation mainly determines the tribological properties of joint prostheses.In this study,we created a polyether-ether-ketone(PEEK)joint prosthesis ...Based on the building principle of additive manufacturing,printing orientation mainly determines the tribological properties of joint prostheses.In this study,we created a polyether-ether-ketone(PEEK)joint prosthesis using fused filament fabrication and investigated the effects of printing orientation on its tribological properties using a pin-on-plate tribometer in 25% newborn calf serum.An ultrahigh molecular weight polyethylene transfer film is formed on the surface of PEEK due to the mechanical capture of wear debris by the 3D-printed groove morphology,which is significantly impacted by the printing orientation of PEEK.When the printing orientation was parallel to the sliding direction of friction,the number and size of the transfer film increased due to higher steady stress.This transfer film protected the matrix and reduced the friction coefficient and wear rate of friction pairs by 39.13%and 74.33%,respectively.Furthermore,our findings provide a novel perspective regarding the role of printing orientation in designing knee prostheses,facilitating its practical applications.展开更多
Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tes...Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were conducted.The rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of corrosion.In air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking paths.Compared with R-T specimens,N-T specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack tip.The corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of specimen.However,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic dissolution.Owing to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS.展开更多
Climate change and extreme weather pose significant challenges to the traditional viticulture regions.Emerging high-altitude grape-producing regions with diverse orientations have shown great potential in coping with ...Climate change and extreme weather pose significant challenges to the traditional viticulture regions.Emerging high-altitude grape-producing regions with diverse orientations have shown great potential in coping with this challenge.Stable,high-quality wine grape production may be achieved by synchronizing the meso-and microclimate.To clarify the role of high altitude and row orientation in meso-and microclimate and the response of berries to it,we evaluated seven years(2012-2018)of climate data,two years of basic grape(Cabernet Sauvignon,Vitis vinifera L.)quality,and one-year microclimate from veraison to harvest.By comparing two locations(Sidon 2047 m,Sinon 2208 m)in Yunnan Province,China,we found that the average temperature has been stable at approximately 15℃ for seven years,with no extreme weather or,noticeable global warming.The light intensity(LI)in the north-south(NS)was more balanced than the east-west(EW)direction,and the east-west to the south(EW-S)canopy side was almost higher than the other sides.High LI was associated with high photosynthetically active radiation(PAR),ultraviolet(UV),and infrared(IR)light and vice versa.The north-south to the east(NS-E)and east-west to the north(EWN)sides were characterized by lower LI and higher UV and IR light,and higher total anthocyanin content.Most anthocyanin synthesis-related genes,for example,VvF3'H and VvF3'5'H,were highly expressed in NS-E from veraison to maturity.Perhaps UV and IR light induced their expression.This study provides new insights on the role of differently orientated rows in controlling grape quality due to varied light quality.The findings are globally significant,particularly in the context of climate change,and offer fresh insights into berry physiological responses and decision-making for the management of existing vineyards.展开更多
Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in t...Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.展开更多
The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic ...The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic and dietary factors,as well as the prevalence of biliary parasites.In the last century,owing to migration,its global incidence has increased.The main pathophysiological mechanisms involve cholangitis,bile infection and biliary strictures,creating a self-sustaining cycle that perpetuates the disease,frequently characterised by recurrent episodes of bacterial infection referred to as syndrome of“recurrent pyogenic cholangitis”.Furthermore,long-standing hepatolithiasis is a known risk factor for development of intrahepatic cholangiocarcinoma.Various classifications have aimed at providing useful insight of clinically relevant aspects and guidance for treatment.The management of symptomatic patients and those with complications can be complex,and relies upon a multidisciplinary team of hepatologists,endoscopists,interventional radiologists and hepatobiliary surgeons,with the main goal being to offer relief from the clinical presentations and prevent the development of more serious complications.This comprehensive review provides insight on various aspects of hepatolithiasis,with a focus on epidemiology,new evidence on pathophysiology,most important clinical aspects,different classification systems and contemporary management.展开更多
Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and...Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.展开更多
MgO nanosheets with exposed(111) facets were obtained through the preparation of Mg(OH)2 precursor by a hydrothermal method in the presence of oleylamine and subsequent calcination in air. The different preferred ...MgO nanosheets with exposed(111) facets were obtained through the preparation of Mg(OH)2 precursor by a hydrothermal method in the presence of oleylamine and subsequent calcination in air. The different preferred orientational assemblies of Mg O nanosheets, achieved by adjusting the polarity of dispersing solvents(ethanol and cyclohexane) during the sample preparation, show different structural and spectral features.展开更多
The Boya-02 kimberlite was identified at depth by geophysical survey work (a single-probe AM survey in 1997 and a gravity survey in 2006) that De Beers DRC Exploration carried out around anomaly 193/172/0019. This ano...The Boya-02 kimberlite was identified at depth by geophysical survey work (a single-probe AM survey in 1997 and a gravity survey in 2006) that De Beers DRC Exploration carried out around anomaly 193/172/0019. This anomaly located approximately 50 km southwest of the town of Mbuji-Mayi in the Kasaï-Oriental Province in the DRC should therefore be the subject of detailed exploration with the aim of better identifying and describing this kimberlite. Thus, through exploratory work and cross-checking of geophysical and geological data, the discovery of this Massif was made by drilling on the aeromagnetic anomaly 193/172/X298. Based on drilling, sampling and laboratory petrographic analysis reports, the Boya-02 kimberlite was classified among highly diluted re-sedimented volcaniclastic kimberlites (KVR), rich in olivine and incidentally in quartz and poor in juvenile substances. This kimberlite represents a deposit of very low economic interest following extremely high dilution. The Boya-02 kimberlite was modeled using ground magnetism data. It is a complex anomaly comprising 2 components with variable amplitude appearing on a subtly magnetized linear detail. The modeled dimensions of two components of this anomaly are 0.32 Ha and 0.2 Ha at depths of 32 m & 14 m for the deposits to the West and the East respectively. Garnet data for the Boya-02 occurrence reports a maximum Pmin value of 49.7 kbar (207 garnets). These data demonstrate the high diamond potential which assumes a conductive cratonic geotherm of 40 mWm<sup>2</sup>.展开更多
To make the problems of existing high requirements of calibration tools, complex global calibration process addressed for monocular multi-view visual measurement system during measurement, in the paper, a global calib...To make the problems of existing high requirements of calibration tools, complex global calibration process addressed for monocular multi-view visual measurement system during measurement, in the paper, a global calibration method is proposed for the geometric properties of rotational correlation motion and the absolute orientation of the field of view without over lap. Firstly, a dual-camera system is constructed for photographing and collecting the rotating image sequence of two flat targets rigidly connected by a long rod at different positions, and based on the known parameters, such as, target feature image, world coordinates, camera internal parameters and so on, then the global PnP optimization method is used to solve the rotation axis and the reference point at different positions;Then, the absolute orientation matrix is constructed based on the parameters of rotation axis, reference point and connecting rod length obtained by this method. In the end, the singular value decomposition method is used to find the optimal rotation matrix, and then get the translation matrix. It’s shown based on simulation and actual tests that in comparison with the existing methods, the maximum attitude and pose errors is 0.0083˚ and 0.3657 mm, respectively, which improves the accuracy by 27.8% and 24.4%, respectively. The calibration device in this paper is simple, and there are no parallel, vertical and coplanar requirements between multiple rotating positions. At the same time, in view of the calibration accuracy, the accuracy requirements of most application scenarios can be met.展开更多
Single nanoparticle tracking(SPT)is a unique and powerful tool to investigate the interaction between nanoparticles and cells,which is of considerable importance for nanotechnology applications in biomedical fields an...Single nanoparticle tracking(SPT)is a unique and powerful tool to investigate the interaction between nanoparticles and cells,which is of considerable importance for nanotechnology applications in biomedical fields and in-depth understanding of biological activities.However,previous work typically focused on translations of single nanoparticles while they undergo both translational and rotational motions.In this study,we obtained both the translational and rotational dynamics of single gold nanorods during their cellular internalization process using dual-channel polarization microscopy.In particular,the azimuth and polar angles were integrated into a polar coordinate systemto obtain three general orientation distribution patterns,found to have a close relationship with the nanoparticle cellular internalization process and time-dependent alterations.Moreover,the patterns accompanied by trajectories,translational and rotational coefficients,the azimuth and polar angles,and other parameters provided a wealth of knowledge on the nanoparticle cellular internalization dynamics with unprecedented details.We observed that the gold nanorods could initially assume a tip-first quick rotation state with partially restricted orientations,then change to a strongly confined near-vertical insertion state with slight angular fluctuations,and eventually transform into a random and fast rotation state.Our methodology opens up a new avenue for a detailed understanding of biological processes.展开更多
Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior coll...Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior colliculus of the cat have, to some extent, orientational selectivity. The significance of this selectivity is discussed in reference to its morphological substrate and physiological functions. In addition, both the directional and orientational selectivities in the superior colliculus are relatively weak when compared with those in the primary visual cortex, and the majority of the neurons prefer upward or downward motion in the visual field.展开更多
基金Supported by the National Natural Science Foundation of China
文摘The present paper deals with the induced orientational order of the probe molecules dissolved in the uniaxially strained rubbers measured by using deuterium NMR. The distinctive dependence of the quadrupolar splitting on the swelling, elongation and crosslinking density was observed. The orientational order arising from the correlation between chain segments decreases with the increase of the numbers of both links between junctions and solvent molecules around segments.
文摘As a part of our systematic study of the physical properties of the compounds of symmetric liquid crystal dimer homologous series, α,ω-bis-(4-n-alkylaniline benzylidene-4’-oxy) alkanes (m.OnO.m), we report here an optical study of two nematogenic compounds of this series viz., 6.O12O.6 and 7.O12O.7 by carrying out the measurement of extraordinary and ordinary refractive indices using modified spectrometer. The molecular polarizability anisotropies are evaluated using Lippincott δ-function model, the molecular vibration method, Haller’s extrapolation method and scaling factor method. The molecular polrizabilities, αe and αo are calculated using Vuks’ isotropic field model and Neugebauer’s anisotropic field model. The orientational order parameter, S, is estimated by using the molecular polarizability values calculated from refractive index and denstity data as well as polarizability anisotropy values calculated as a function of temperature in the nematic phase of both of the dimers. These values are discussed with reference to the order parameter values obtained directly from the optical birefringence, Δn, data without assuming any internal field. A comparison of the order parameter values from all of these methods was carried out in the light of available literature data.
文摘The orientational order is an important concept of the materials composed of large molecules or clusters. Using high-resolution scanning tunneling microscopy, we have studied the orientational order of two kinds of typical low-dimensional C60 lattices: two-dimensional molecules array and C60(111) multi-layer film surface. Due to the change of the crystal field, their orientational orders are distinctly different from those in bulk system, and some unique phenomena appear.
文摘New concepts such as intramolecular orientational order parameter and corresponding model as well as theory were proposed to describe the intramolecular orientation of mesogenic units in the liquid crystalline polymer chains. The relationship between the intramolecular orientational order parameter and the molecular geometrical parameters such as the bond angle, the bond rotational angle and the rotational potential energy of chemical bonds was deduced. A significant even-odd oscillation of the intramolecular orientational order parameter of LCPs with different length of flexible spacer was found and rationally related to even-odd zig-zag manner of transition properties The verification and application of the theory are also discussed. The isotropic transition temperature predicted by the theory is shown to be in favourable agreement with the experiments.
基金The authors are grateful to the Province Natural Science Foundation of Zhejiang(Grant No.LQ19E050004)for financial support.The authors also graciously thank China Airlines Shenyang Liming Aeroengine Co.,Ltd.for aiding in providing the experimental Inconel 718 alloys.
文摘Due to the important role ofδphase's quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components,it is necessary to renew insights into the effect of cold deformation on theδphase precipitation,especially on the morphology evolution.Therefore,the nucleation and growth behavior ofδphase in cold-rolled Inconel 718 alloy during aging were investigated.The results show that the precipitation rate and volume fraction ofδphase increase with increasing the cold rolling reduction from 10%to 50%.The volume fraction ofδphase reaches equilibrium after 5 h,remaining at 5.98%,6.52%,and 6.79%under different rolling reductions(10%,30%,and 50%),respectively.The nucleation ofδphase mainly occurs on different sites(grain boundaries,new twin boundaries and old twin boundaries)under 10%rolling reduction,whileδphase mainly nucleates on the new grain boundaries of static recrystallization due to 50%rolling reduction.And the growth ofδphase undergoes a process of alternate orientation growth from spherical(nucleation)→short rod(longitudinal orientation growth)→short rod(radial orientation growth)→dynamic equilib-rium.Under 10%rolling reduction,δphase tends to grow into the matrix,while under 50%rolling reduction,the orientation grows faster and is easily affected by the grain boundary curvature.
基金Supported by the State Commission of Science and Technology, the National Natural Science Foundation and the State Education Commission of China.
文摘Re-innervation of sensory and motor neurons on a defined area of the body wall was studied in two species of leeches, Whitmania pigra and Hirudo medicinalis, as a model of segmental animals. Following isolation and rotation of a tube of body wall, the mechanical sensory and annular erection (AE) motor neurons re-innervated the body wall, at a rate of approximately 3. 8 -8. 4 μm/h. The patterns of re-innerva-tion by pairs of neurons on each side of a ganglion were bilaterally symmetric. The repairs are synchronous for the sensory and motor neurons which are of different functions but in a same ganglion. The gap junctions are widely spread in leech between neurons and glia cells, as well as among the neurons and glia cells themselves. Therefore, it is proposed that the nervous system repair is regulated by a low-resistance pathway. In the xenotransplantation experiments, neurons recognized target tissues before the immuno-recognition and rejection.
基金the Natural Science Foundation of China(Grant Nos.82072413,82101649)National Key Research and Development Program of China(Grant Nos.2021YFE0105400).
文摘The integrated repair of bone and cartilage boasts advantages for osteochondral restoration such as a long-term repair effect and less deterioration compared to repairing cartilage alone.Constructing multifactorial,spatially oriented scaffolds to stimulate osteochondral regeneration,has immense significance.Herein,targeted drugs,namely kartogenin@polydopamine(KGN@PDA)nanoparticles for cartilage repair and miRNA@calcium phosphate(miRNA@CaP)NPs for bone regeneration,were in situ deposited on a patterned supramolecular-assembled 2-ureido-4[lH]-pyrimidinone(UPy)modified gelation hydrogel film,facilitated by the dynamic and responsive coordination and complexation of metal ions and their ligands.This hydrogel film can be rolled into a cylindrical plug,mimicking the Haversian canal structure of natural bone.The resultant hydrogel demonstrates stable mechanical properties,a self-healing ability,a high capability for reactive oxygen species capture,and controlled release of KGN and miR-26a.In vitro,KGN@PDA and miRNA@CaP promote chondrogenic and osteogenic differentiation of mesenchymal stem cells via the JNK/RUNX1 and GSK-3β/β-catenin pathways,respectively.In vivo,the osteochondral plug exhibits optimal subchondral bone and cartilage regeneration,evidenced by a significant increase in glycosaminoglycan and collagen accumulation in specific zones,along with the successful integration of neocartilage with subchondral bone.This biomaterial delivery approach represents a significant toward improved osteochondral repair.
基金This study was supported by the following funds:National Key R&D Program of China(No.2018YFE0207900)Program for Innovation Team of Shaanxi Province(No.2023-CXTD-17)+5 种基金Program of the National Natural Science Foundation of China(No.51835010)Key R&D Program of Guangdong Province(No.2018B090906001)Natural Science Basic Research Program of Shaanxi Province(No.2022JQ-378)China Postdoctoral Science Foundation(No.2020M683458)Fundamental Research Funds for the Central Universities(8)Youth Innovation Team of Shaanxi Universities.
文摘Based on the building principle of additive manufacturing,printing orientation mainly determines the tribological properties of joint prostheses.In this study,we created a polyether-ether-ketone(PEEK)joint prosthesis using fused filament fabrication and investigated the effects of printing orientation on its tribological properties using a pin-on-plate tribometer in 25% newborn calf serum.An ultrahigh molecular weight polyethylene transfer film is formed on the surface of PEEK due to the mechanical capture of wear debris by the 3D-printed groove morphology,which is significantly impacted by the printing orientation of PEEK.When the printing orientation was parallel to the sliding direction of friction,the number and size of the transfer film increased due to higher steady stress.This transfer film protected the matrix and reduced the friction coefficient and wear rate of friction pairs by 39.13%and 74.33%,respectively.Furthermore,our findings provide a novel perspective regarding the role of printing orientation in designing knee prostheses,facilitating its practical applications.
基金the National Natural Science Foundation of China(Nos.52175143 and 51571150)。
文摘Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium alloys.To investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were conducted.The rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of corrosion.In air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking paths.Compared with R-T specimens,N-T specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack tip.The corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of specimen.However,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic dissolution.Owing to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS.
基金supported by the National Natural Science Foundation of China(Grant No.31772258)the National Key Research and Development Program(Grant No.2019YFD1000102-11)。
文摘Climate change and extreme weather pose significant challenges to the traditional viticulture regions.Emerging high-altitude grape-producing regions with diverse orientations have shown great potential in coping with this challenge.Stable,high-quality wine grape production may be achieved by synchronizing the meso-and microclimate.To clarify the role of high altitude and row orientation in meso-and microclimate and the response of berries to it,we evaluated seven years(2012-2018)of climate data,two years of basic grape(Cabernet Sauvignon,Vitis vinifera L.)quality,and one-year microclimate from veraison to harvest.By comparing two locations(Sidon 2047 m,Sinon 2208 m)in Yunnan Province,China,we found that the average temperature has been stable at approximately 15℃ for seven years,with no extreme weather or,noticeable global warming.The light intensity(LI)in the north-south(NS)was more balanced than the east-west(EW)direction,and the east-west to the south(EW-S)canopy side was almost higher than the other sides.High LI was associated with high photosynthetically active radiation(PAR),ultraviolet(UV),and infrared(IR)light and vice versa.The north-south to the east(NS-E)and east-west to the north(EWN)sides were characterized by lower LI and higher UV and IR light,and higher total anthocyanin content.Most anthocyanin synthesis-related genes,for example,VvF3'H and VvF3'5'H,were highly expressed in NS-E from veraison to maturity.Perhaps UV and IR light induced their expression.This study provides new insights on the role of differently orientated rows in controlling grape quality due to varied light quality.The findings are globally significant,particularly in the context of climate change,and offer fresh insights into berry physiological responses and decision-making for the management of existing vineyards.
基金supported by National Natural Science Foundation of China (52070194,52073309)Natural Science Foundation of Hunan Province (2022JJ20069)。
文摘Generally,layered Ni-rich cathode materials exhibit the morphology of polycrystalline secondary sphere composed of numerous primary particles.While the arrangement of primary particles plays a very important role in the properties of Ni-rich cathodes.The disordered particle arrangement is harmful to the cyclic performance and structural stability,yet the fundamental understanding of disordered structure on the structural degradation behavior is unclarified.Herein,we have designed three kinds of LiNi_(0.83)Co_(0.06)Mn_(0.11)O_(2) cathode materials with different primary particle orientations by regulating the precursor coprecipitation process.Combining finite element simulation and in-situ characterization,the Li^(+)transport and structure evolution behaviors of different materials are unraveled.Specifically,the smooth Li^(+)diffusion minimizes the reaction heterogeneity,homogenizes the phase transition within grains,and mitigates the anisotropic microstructural change,thereby modulating the crack evolution behavior.Meanwhile,the optimized structure evolution ensures radial tight junctions of the primary particles,enabling enhanced Li^(+)diffusion during dynamic processes.Closed-loop bidirectional enhancement mechanism becomes critical for grain orientation regulation to stabilize the cyclic performance.This precursor engineering with particle orientation regulation provides the useful guidance for the structural design and feature enhancement of Ni-rich layered cathodes.
文摘The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic and dietary factors,as well as the prevalence of biliary parasites.In the last century,owing to migration,its global incidence has increased.The main pathophysiological mechanisms involve cholangitis,bile infection and biliary strictures,creating a self-sustaining cycle that perpetuates the disease,frequently characterised by recurrent episodes of bacterial infection referred to as syndrome of“recurrent pyogenic cholangitis”.Furthermore,long-standing hepatolithiasis is a known risk factor for development of intrahepatic cholangiocarcinoma.Various classifications have aimed at providing useful insight of clinically relevant aspects and guidance for treatment.The management of symptomatic patients and those with complications can be complex,and relies upon a multidisciplinary team of hepatologists,endoscopists,interventional radiologists and hepatobiliary surgeons,with the main goal being to offer relief from the clinical presentations and prevent the development of more serious complications.This comprehensive review provides insight on various aspects of hepatolithiasis,with a focus on epidemiology,new evidence on pathophysiology,most important clinical aspects,different classification systems and contemporary management.
基金support from the National Natural Science Foundation of China(Grant Nos.11974066,12174041,12104134,T2350007,and 12347178)the Fundamental and Advanced Research Program of Chongqing(Grant No.cstc2019jcyj-msxm X0477)+3 种基金the Natural Science Foundation of Chongqing(Grant No.CSTB2022NSCQMSX1260)the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202301333)the Scientific Research Fund of Chongqing University of Arts and Sciences(Grant Nos.R2023HH03 and P2022HH05)College Students’Innovation and Entrepreneurship Training Program of Chongqing Municipal(Grant No.S202310642002)。
文摘Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and metastasis.However,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell migration.Fortunately,the further development of microfluidic technology has provided solutions for the study of such questions.We utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,respectively.By combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP cells.The results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences observed.Furthermore,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration side.However,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is weak.These findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is diminished.The RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.
基金supported by the National Natural Science Foundation of China (Nos. 21673046, 21473036, 21371035, 91645201)
文摘MgO nanosheets with exposed(111) facets were obtained through the preparation of Mg(OH)2 precursor by a hydrothermal method in the presence of oleylamine and subsequent calcination in air. The different preferred orientational assemblies of Mg O nanosheets, achieved by adjusting the polarity of dispersing solvents(ethanol and cyclohexane) during the sample preparation, show different structural and spectral features.
文摘The Boya-02 kimberlite was identified at depth by geophysical survey work (a single-probe AM survey in 1997 and a gravity survey in 2006) that De Beers DRC Exploration carried out around anomaly 193/172/0019. This anomaly located approximately 50 km southwest of the town of Mbuji-Mayi in the Kasaï-Oriental Province in the DRC should therefore be the subject of detailed exploration with the aim of better identifying and describing this kimberlite. Thus, through exploratory work and cross-checking of geophysical and geological data, the discovery of this Massif was made by drilling on the aeromagnetic anomaly 193/172/X298. Based on drilling, sampling and laboratory petrographic analysis reports, the Boya-02 kimberlite was classified among highly diluted re-sedimented volcaniclastic kimberlites (KVR), rich in olivine and incidentally in quartz and poor in juvenile substances. This kimberlite represents a deposit of very low economic interest following extremely high dilution. The Boya-02 kimberlite was modeled using ground magnetism data. It is a complex anomaly comprising 2 components with variable amplitude appearing on a subtly magnetized linear detail. The modeled dimensions of two components of this anomaly are 0.32 Ha and 0.2 Ha at depths of 32 m & 14 m for the deposits to the West and the East respectively. Garnet data for the Boya-02 occurrence reports a maximum Pmin value of 49.7 kbar (207 garnets). These data demonstrate the high diamond potential which assumes a conductive cratonic geotherm of 40 mWm<sup>2</sup>.
文摘To make the problems of existing high requirements of calibration tools, complex global calibration process addressed for monocular multi-view visual measurement system during measurement, in the paper, a global calibration method is proposed for the geometric properties of rotational correlation motion and the absolute orientation of the field of view without over lap. Firstly, a dual-camera system is constructed for photographing and collecting the rotating image sequence of two flat targets rigidly connected by a long rod at different positions, and based on the known parameters, such as, target feature image, world coordinates, camera internal parameters and so on, then the global PnP optimization method is used to solve the rotation axis and the reference point at different positions;Then, the absolute orientation matrix is constructed based on the parameters of rotation axis, reference point and connecting rod length obtained by this method. In the end, the singular value decomposition method is used to find the optimal rotation matrix, and then get the translation matrix. It’s shown based on simulation and actual tests that in comparison with the existing methods, the maximum attitude and pose errors is 0.0083˚ and 0.3657 mm, respectively, which improves the accuracy by 27.8% and 24.4%, respectively. The calibration device in this paper is simple, and there are no parallel, vertical and coplanar requirements between multiple rotating positions. At the same time, in view of the calibration accuracy, the accuracy requirements of most application scenarios can be met.
基金supported by the National Natural Science Foundation of China(grant nos.21127009,21221003,and 21425519)the Training Program for Excellent Young Innovators of Changsha(grant no.kq1905061)the Natural Science Foundation of Hunan Province,China(grant no.020RC3042).
文摘Single nanoparticle tracking(SPT)is a unique and powerful tool to investigate the interaction between nanoparticles and cells,which is of considerable importance for nanotechnology applications in biomedical fields and in-depth understanding of biological activities.However,previous work typically focused on translations of single nanoparticles while they undergo both translational and rotational motions.In this study,we obtained both the translational and rotational dynamics of single gold nanorods during their cellular internalization process using dual-channel polarization microscopy.In particular,the azimuth and polar angles were integrated into a polar coordinate systemto obtain three general orientation distribution patterns,found to have a close relationship with the nanoparticle cellular internalization process and time-dependent alterations.Moreover,the patterns accompanied by trajectories,translational and rotational coefficients,the azimuth and polar angles,and other parameters provided a wealth of knowledge on the nanoparticle cellular internalization dynamics with unprecedented details.We observed that the gold nanorods could initially assume a tip-first quick rotation state with partially restricted orientations,then change to a strongly confined near-vertical insertion state with slight angular fluctuations,and eventually transform into a random and fast rotation state.Our methodology opens up a new avenue for a detailed understanding of biological processes.
基金Project supported by the National Natural Science Foundation of China and the Chinese Academy of Sciences.
文摘Based on quantitative analyses of the response characteristics of visual neurons in the superior colliculus to moving optical bar stimuli, it is demonstrated for the first time that the visual neurons in superior colliculus of the cat have, to some extent, orientational selectivity. The significance of this selectivity is discussed in reference to its morphological substrate and physiological functions. In addition, both the directional and orientational selectivities in the superior colliculus are relatively weak when compared with those in the primary visual cortex, and the majority of the neurons prefer upward or downward motion in the visual field.