The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external disturbances.This paper proposes a barrier function-base...The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external disturbances.This paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for NWMRs.Compared with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances bounds.Another advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier function.The benefit is that the overestimation of control gain can be eliminated,resulting in chattering reduction.Moreover,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the actuator.The stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.展开更多
Acyl-CoA-binding proteins(ACBPs)are important for the transport of acyl groups for macro molecular biosynthesis involved in plant growth,development,and diverse stress(e.g.,cold,drought,salinity,and heavy metals)respo...Acyl-CoA-binding proteins(ACBPs)are important for the transport of acyl groups for macro molecular biosynthesis involved in plant growth,development,and diverse stress(e.g.,cold,drought,salinity,and heavy metals)responses.Here,we report the phylogeny and characteristics of the ACBP family in the woody plant Populus trichocarpa.Eight genes encoding ACBP proteins were identified,and they are distributed on eight chromosomes in P.trichocarpa.These PtACBP genes were divided into four subgroups according to gene structure,conserved motifs and phylogenetic relationship.Promoter analysis revealed that cis-elements were related to stress response,phytohormone response,and physical and reproductive growth regulation.Expression levels of PtACBP genes varied among different organs,with the highest expression in leaves and the lowest in stems.Quantitative real-time PCR(qRT-PCR)analysis showed that under salinity-alkali stresses(i.e.,200 mM NaCl,75 mM Na2CO3,and 100 mM NaHCO3),four(PtACBP1,PtACBP3,PtACBP4 and PtACBP8)of eight PtACBP genes were significantly induced in roots and leaves.These data provide a comprehensive analysis of the ACBPs family in P.trichocarpa,which could be useful for gene function analyses.展开更多
Straw utilization is a key issue related to agricultural production and air pollution control.In this study,a novel extrusion process was proposed to improve the physical and mechanical properties of the straw-reinfor...Straw utilization is a key issue related to agricultural production and air pollution control.In this study,a novel extrusion process was proposed to improve the physical and mechanical properties of the straw-reinforced linear low-density polyethylene(LLDPE)composite.Instead of crushing the straw and mixing it with plastic matrix,the new method mixes straw with plastic matrix in its original form.The intact long rice straws were parallelly spread on the LLDPE film and then rolled up together into a prefabricated roll.The rolls experienced three extrusion processes as follows:(1)twin-screw melting,cooling and crushing,single-screw extruding;(2)twin-screw melting and single-screw extruding;(3)directly single-screw extruding.The testing results showed that the straw/LLDPE composite(with a ratio of 6:4)prepared by Method(2)exhibited optimized properties.Characterization by scanning electron microscopy indicated that the damage to rice straw fibers was relatively minor,the orientation of long fibers was good,and the binding of fibers with the LLDPE matrix was excellent in this case.The results of dynamic mechanical testing(DMA),differential scanning calorimetry(DSC)and thermogravimetric(TG)analysis demonstrated that composites prepared by the new process exhibited significantly improved thermal stability and energy storage modulus,compared with those prepared by conventional processes(e.g.,extruded straw particles/LLDPE composite).The new proposed method yielded significantly enhanced mechanical properties while reducing dust pollution.展开更多
The publication of ISO 15686-5 is significant for studies related to the life-cycle costs of buildings. Among the many economic evaluation methods, the NPV method is recommended for use by this standard. This stu...The publication of ISO 15686-5 is significant for studies related to the life-cycle costs of buildings. Among the many economic evaluation methods, the NPV method is recommended for use by this standard. This study explains the concept and method of PV, and then provides an explanation of the concept and method of NPV, and points out the limitations in the practical application of the method.展开更多
This study aimed to introduce a novel mini-open pedicle screw fixation technique via Wiltse approach, and com- pared it with the traditional posterior open method. A total of 72 cases of single-segment thoracolumbar f...This study aimed to introduce a novel mini-open pedicle screw fixation technique via Wiltse approach, and com- pared it with the traditional posterior open method. A total of 72 cases of single-segment thoracolumbar fractures without neurologic injury underwent pedicle screw fixation via two different approaches. Among them, 37 patients were treated using posterior open surgery, and 35 patients received mini-open operation via Wiltse approach. Crew placement accuracy rate, operative time, blood loss, postoperative drainage, postoperative hospitalization time, radiation exposure time, postoperative improvement in R value, Cobb's angle and visual analog scale (VAS) scores of the two methods were compared. There were no significant differences in the accuracy rate of pedicle screw placement, radiation exposure and postoperative R value and Cobb's angle improvement between the two groups. However, the mini-open method had obvious advantages over the conventional open method in operative time, blood loss, postoperative drainage, postoperative hospitalization time, and postoperative improvement in VAS. The mini-open pedicle screw technique could be applied in treatment of single-segment thoracolumbar fracture without neurologic injury and had advantages of less tissue trauma, short operative and rehabilitative time on the premise of guaranteed accuracy rate and no increased radiation exposure.展开更多
We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the t...We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the tho- racic or/and lumbar spine were alternately assigned to either the new free-hand or the conventional group. In the new free-hand technique group, preoperative computerized tomography (CT) images were used to calculate the targeted medial-lateral angle of each pedicle trajectory and the pedicle screw was inserted perpendicular to the corresponding supraspinal ligament. In the conventional technique group, the medial-lateral and cranial-caudal angle of each pedicle trajectory was determined by intraoperatively under fluoroscopic guidance. The accuracy rate of pedicle screw placement, the time of intraoperative fluoroscopy, the operating time and the amount of blood loss during operation were respectively compared. All screws were analyzed by using intraoperative ra- diographs, intraoperative triggered electromyography (EMG) monitoring data, postoperative CT data and clinical outcomes. The accuracy rate of pedicle screw placement in the new free-hand technique group and the conven- tional technique group was 96.3% and 94.2% (P 〈 0.05), respectively. The intraoperative fluoroscopy time of the new technique group was less than that of the conventional technique group (5.37 seconds vs. 8.79 seconds, P 〈 0.05). However, there was no statistical difference in the operating time and the amount of blood loss during op- eration (P 〉 0.05). Pedicle screw placement with the free-hand technique which keeps the screw perpendicular to the supraspinal ligament is an accurate, reliable and safe technique to treat simple fracture in the thoracic or lum- bar spine.展开更多
The fast and accurate identification of nerve tracts is critical for successful nerve anastomosis. Taking advantage of differences in acetylcholinesterase content between the spinal ventral and dorsal roots, we develo...The fast and accurate identification of nerve tracts is critical for successful nerve anastomosis. Taking advantage of differences in acetylcholinesterase content between the spinal ventral and dorsal roots, we developed a novel quartz crystal microbalance method to distinguish between these nerves based on acetylcholinesterase antibody reactivity. The acetylcholinesterase antibody was immobilized on the electrode surface of a quartz crystal microbalance and reacted with the acetylcholinesterase in sample solution. The formed antigen and antibody complexes added to the mass of the electrode inducing a change in frequency of the electrode. The spinal ventral and dorsal roots were distinguished by the change in frequency. The ventral and dorsal roots were cut into 1 to 2-mm long segments and then soaked in 250 pL PBS. Acetylcholinesterase antibody was immobilized on the quartz crystal microbalance gold electrode surface. The results revealed that in 10 minutes, both spinal ventral and dorsal roots induced a frequency change; however, the frequency change induced by the ventral roots was notably higher than that induced by the dorsal roots. No change was induced by bovine serum albumin or PBS. These results clearly demonstrate that a quartz crystal microbalance sensor can be used as a rapid, highly sensitive and accurate detection tool for the quick identification of spinal nerve roots intraoperatively.展开更多
Compressing encrypted images remains a challenge.As illustrated in our previous work on compression of encrypted binary images,it is preferable to exploit statistical characteristics at the receiver.Through this line,...Compressing encrypted images remains a challenge.As illustrated in our previous work on compression of encrypted binary images,it is preferable to exploit statistical characteristics at the receiver.Through this line,we characterize statistical correlations between adjacent bitplanes of a gray image with the Markov random field(MRF),represent it with a factor graph,and integrate the constructed MRF factor graph in that for binary image reconstruction,which gives rise to a joint factor graph for gray images reconstruction(JFGIR).By exploiting the JFGIR at the receiver to facilitate the reconstruction of the original bitplanes and deriving theoretically the sum-product algorithm(SPA)adapted to the JFGIR,a novel MRF-based encryption-then-compression(ETC)scheme is thus proposed.After preferable universal parameters of the MRF between adjacent bitplanes are sought via a numerical manner,extensive experimental simulations are then carried out to show that the proposed scheme successfully compresses the first 3 and 4 most significant bitplanes(MSBs)for most test gray images and the others with a large portion of smooth area,respectively.Thus,the proposed scheme achieves significant improvement against the state-of-the-art leveraging the 2-D Markov source model at the receiver and is comparable or somewhat inferior to that using the resolution-progressive strategy in recovery.展开更多
BACKGROUND In order to improve risk stratification and clinical management of the pancreatic ductal adenocarcinoma(PDAC),the American Joint Committee on Cancer(AJCC)has published its eighth edition staging manual.Some...BACKGROUND In order to improve risk stratification and clinical management of the pancreatic ductal adenocarcinoma(PDAC),the American Joint Committee on Cancer(AJCC)has published its eighth edition staging manual.Some major changes have been introduced in the new staging system for both T and N categories.Given the rarity of resectable disease,distal pancreatic cancer is likely underrepresented in the published clinical studies,and how the impact of the staging system actually reflects on to clinical outcomes remain unclear.AIM To validate the AJCC 8th edition of TNM staging in distal PDAC.METHODS A retrospective cohort study was performed in seven academic medical centers in the United States.Clinicopathological prognostic factors associated with progression-free survival(PFS)and overall survival(OS)were evaluated through univariate and multivariate analyses.RESULTS Overall,454 patients were enrolled in the study,and were divided into 2 subgroups:Invasive intraductal papillary mucinous neoplasms(IPMN)(115 cases)and non-IPMN associated adenocarcinoma(339 cases).Compared to invasive IPMN,non-IPMN associated adenocarcinomas are more common in relatively younger patients,have larger tumor size,are more likely to have positive lymph nodes,and are associated with a higher tumor(T)stage and nodal(N)stage,lymphovascular invasion,perineural invasion,tumor recurrence,and a worse PFS and OS.The cohort was predominantly categorized as stage 3 per AJCC 7th edition staging manual,and it’s more evenly distributed based on 8th edition staging manual.T and N staging of both 7th and 8th edition sufficiently stratify PFS and OS in the entire cohort,although dividing into N1 and N2 according to the 8th edition does not show additional stratification.For PDAC arising in IPMN,T staging of the 7th edition and N1/N2 staging of the 8th edition appear to further stratify PFS and OS.For PDAC without an IPMN component,T staging from both versions fails to stratify PFS and OS.CONCLUSION The AJCC 8th edition TNM staging system provides even distribution for the T staging,however,it does not provide better risk stratification than previous staging system for distal pancreatic cancer.展开更多
In recent years, sweet potato virus disease (SPVD) has severely affected the production of sweet potato in China. In order to select chemical agents to prevent sweet potato from being infected with SPVD, 14 pesticid...In recent years, sweet potato virus disease (SPVD) has severely affected the production of sweet potato in China. In order to select chemical agents to prevent sweet potato from being infected with SPVD, 14 pesticides were sprayed on the plants of sweet potato infected with SPVD, and the relative mRNA level of the viruses in the leaves and physiological indicators of sweet potato plants were detected. The results showed that after the application of most of the pesticides, the relative mRNA level of the two viruses that caused SPVD decreased, and the chlorophyll content and biomass of sweet potato infected with SPVD increased significantly or extremely significantly. Among the pesticides, BASF virus liquid, 0.1% physcion and Aolike powder for cucumber virus were proved to be the best, as the chlorophyll content and stem length of sweet potato increased significantly. The experiment indicated that the pesticides could reduce the harm of SPVD to sweet potato.展开更多
As a promising technology to improve spectrum efficiency and transmission coverage,Heterogeneous Network(HetNet)has attracted the attention of many scholars in recent years.Additionally,with the introduction of the No...As a promising technology to improve spectrum efficiency and transmission coverage,Heterogeneous Network(HetNet)has attracted the attention of many scholars in recent years.Additionally,with the introduction of the Non-Orthogonal Multiple Access(NOMA)technology,the NOMA-assisted HetNet cannot only improve the system capacity but also allow more users to utilize the same frequency band resource,which makes the NOMA-assisted HetNet a hot topic.However,traditional resource allocation schemes assume that base stations can exactly estimate direct link gains and cross-tier link gains,which is impractical for practical HetNets due to the impact of channel delays and random perturbation.To further improve energy utilization and system robustness,in this paper,we investigate a robust resource allocation problem to maximize the total Energy Efficiency(EE)of Small-Cell Users(SCUs)in NOMA-assisted HetNets under imperfect channel state information.By considering bounded channel uncertainties,the robust resource optimization problem is formulated as a mixed-integer and nonlinear programming problem under the constraints of the cross-tier interference power of macrocell users,the maximum transmit power of small base station,the Resource Block(RB)assignment,and the quality of service requirement of each SCU.The original problem is converted into an equivalent convex optimization problem by using Dinkelbach's method and the successive convex approximation method.A robust Dinkelbach-based iteration algorithm is designed by jointly optimizing the transmit power and the RB allocation.Simulation results verify that the proposed algorithm has better EE and robustness than the existing algorithms.展开更多
Gasification unit is one of the key subsystems in the IGCC power system;the operating parameters of gasifier directly affect syngas quality and performance of whole IGCC system. The system model of gasification unit w...Gasification unit is one of the key subsystems in the IGCC power system;the operating parameters of gasifier directly affect syngas quality and performance of whole IGCC system. The system model of gasification unit with coal water slurry gasifier was simulated and calculated using THERMOFLEX software, and the relations of oxygen coal ratio (Roc), water coal ratio (Rsc), gasification pressure, gasification temperature and cold gas efficiency were mostly researched. The results show that Roc and Rsc have effect of mutual restriction on gasification temperature, cold gas efficiency and syngas composition. Gasification pressure mainly determines the capacity of the gasifier, little effects on syngas composition.展开更多
A plethora of evidence suggests that protein misfolding and aggregation are underlying mechanisms of various neurodegenerative diseases,such as prion diseases and Alzheimer's disease(AD).Like prion diseases,AD has...A plethora of evidence suggests that protein misfolding and aggregation are underlying mechanisms of various neurodegenerative diseases,such as prion diseases and Alzheimer's disease(AD).Like prion diseases,AD has been considered as an infectious disease in the past decades as it shows strain specificity and transmission potential.Although it remains elusive how protein aggregation leads to AD,it is becoming clear that cellular prion protein(PrP^c)plays an important role in AD pathogenesis.Here,we briefly reviewed AD pathogenesis and focused on recent progresses how PrP^c contributed to AD development.In addition,we proposed a potential mechanism to explain why infectious agents,such as viruses,conduce AD pathogenesis.Microbe infections cause AD deposition and upregulation of PrP^c,which lead to high affinity binding between AD oligomers and PrP^c.The interaction between PrP^c and AP oligomers in turn activates the Fyn signaling cascade,resulting in neuron death in the central nervous system(CNS).Thus,silencing PrP^c expression may turn out be an effective treatment for PrP^c dependent AD.展开更多
The management of oral and maxillofacial tissue defects caused by tumors,trauma,and congenital or acquired deformities has been a major challenge for surgeons over the last few decades.Autologous tissue transplantatio...The management of oral and maxillofacial tissue defects caused by tumors,trauma,and congenital or acquired deformities has been a major challenge for surgeons over the last few decades.Autologous tissue transplantation,the gold standard of tissue reconstruction,is a valid method for repairing the oral and maxillofacial functions and aesthetics.However,several limitations hinder its clinical applications including complications of donor sites,limited tissue volume,and uncertain long-term outcomes.Adipose-derived mesenchymal stem cells(ADMSCs)widely exist in adipose tissue and can be easily obtained through liposuction.Like the bone marrow-derived mesenchymal stem cells(BMSCs),ADMSCs also have the multi-pluripotent potencies to differentiate into osteoblasts,chondrocytes,neurons,and myocytes.Therefore,the multilineage capacity of ADMSCs makes them valuable for cell-based medical therapies.In recent years,researchers have developed many candidates of ADMSCs-based biomaterial scaffolds to cater for the needs of oral and maxillofacial tissue engineering due to their superior performance.This review presents the advances and applications of ADMSCs-based biomaterial scaffolds,and explores their tissue engineering prospects in oral and maxillofacial reconstructions.展开更多
As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explo...As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explore the biosilica formation process and fabricate silica with an exquisite microstructure for lithiumion battery(LIB)electrodes,a bacterial phage(M13)is used as a biotemplate to synthesize silica with diverse morphologies:cylinders,hexagonal prisms,assemblies of smaller cylinders and nanowires.A facile ethanol bath method is conducted to coat the nanowires with nitrogen-containing carbon and carbon-coated SiO_(2) nanowires with mesochannels(C@msSiO_(2) NWs)are first used as anode materials for LIBs.Attributed to the uniform carbon coating and parallel mesochannel structure,the electronic conductivity and capacity to accommodate volume variations were significantly improved.In the electrochemical perfo rmance test,the composites calcined at 750℃(C@msSiO_(2) NWs-750)show an impressive capacity of 653 mA h g^(-1) at a current density of 500 mA g^(-1) and stability(1000 cycles).In view of the electrochemical test outcomes,the prepa ration of a sophisticated structure with an outstanding potential is easily achieved via a biomimetic strategy.展开更多
基金the China Scholarship Council(202106690037)the Natural Science Foundation of Anhui Province(19080885QE194)。
文摘The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external disturbances.This paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for NWMRs.Compared with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances bounds.Another advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier function.The benefit is that the overestimation of control gain can be eliminated,resulting in chattering reduction.Moreover,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the actuator.The stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.
基金supported by grants from the Fundamental Research Funds for the Central Universities(Nos.2572018B03)the College Students Innovations Special Project funded by NEFU(No.202010225173)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.2572019CT03)the Natural Science Foundation of Heilongjiang Province(No.ZD2019C003)。
文摘Acyl-CoA-binding proteins(ACBPs)are important for the transport of acyl groups for macro molecular biosynthesis involved in plant growth,development,and diverse stress(e.g.,cold,drought,salinity,and heavy metals)responses.Here,we report the phylogeny and characteristics of the ACBP family in the woody plant Populus trichocarpa.Eight genes encoding ACBP proteins were identified,and they are distributed on eight chromosomes in P.trichocarpa.These PtACBP genes were divided into four subgroups according to gene structure,conserved motifs and phylogenetic relationship.Promoter analysis revealed that cis-elements were related to stress response,phytohormone response,and physical and reproductive growth regulation.Expression levels of PtACBP genes varied among different organs,with the highest expression in leaves and the lowest in stems.Quantitative real-time PCR(qRT-PCR)analysis showed that under salinity-alkali stresses(i.e.,200 mM NaCl,75 mM Na2CO3,and 100 mM NaHCO3),four(PtACBP1,PtACBP3,PtACBP4 and PtACBP8)of eight PtACBP genes were significantly induced in roots and leaves.These data provide a comprehensive analysis of the ACBPs family in P.trichocarpa,which could be useful for gene function analyses.
基金supported by the Natural Science Foundation of China(No.32071704).
文摘Straw utilization is a key issue related to agricultural production and air pollution control.In this study,a novel extrusion process was proposed to improve the physical and mechanical properties of the straw-reinforced linear low-density polyethylene(LLDPE)composite.Instead of crushing the straw and mixing it with plastic matrix,the new method mixes straw with plastic matrix in its original form.The intact long rice straws were parallelly spread on the LLDPE film and then rolled up together into a prefabricated roll.The rolls experienced three extrusion processes as follows:(1)twin-screw melting,cooling and crushing,single-screw extruding;(2)twin-screw melting and single-screw extruding;(3)directly single-screw extruding.The testing results showed that the straw/LLDPE composite(with a ratio of 6:4)prepared by Method(2)exhibited optimized properties.Characterization by scanning electron microscopy indicated that the damage to rice straw fibers was relatively minor,the orientation of long fibers was good,and the binding of fibers with the LLDPE matrix was excellent in this case.The results of dynamic mechanical testing(DMA),differential scanning calorimetry(DSC)and thermogravimetric(TG)analysis demonstrated that composites prepared by the new process exhibited significantly improved thermal stability and energy storage modulus,compared with those prepared by conventional processes(e.g.,extruded straw particles/LLDPE composite).The new proposed method yielded significantly enhanced mechanical properties while reducing dust pollution.
文摘The publication of ISO 15686-5 is significant for studies related to the life-cycle costs of buildings. Among the many economic evaluation methods, the NPV method is recommended for use by this standard. This study explains the concept and method of PV, and then provides an explanation of the concept and method of NPV, and points out the limitations in the practical application of the method.
基金supported by the National Natural Science Foundation of China(Grant No.30973058, 81171694,and 81371968)the Program for Development of Innovative Research Team in the First Affiliated Hospital of NJMU(No.IRT-015)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘This study aimed to introduce a novel mini-open pedicle screw fixation technique via Wiltse approach, and com- pared it with the traditional posterior open method. A total of 72 cases of single-segment thoracolumbar fractures without neurologic injury underwent pedicle screw fixation via two different approaches. Among them, 37 patients were treated using posterior open surgery, and 35 patients received mini-open operation via Wiltse approach. Crew placement accuracy rate, operative time, blood loss, postoperative drainage, postoperative hospitalization time, radiation exposure time, postoperative improvement in R value, Cobb's angle and visual analog scale (VAS) scores of the two methods were compared. There were no significant differences in the accuracy rate of pedicle screw placement, radiation exposure and postoperative R value and Cobb's angle improvement between the two groups. However, the mini-open method had obvious advantages over the conventional open method in operative time, blood loss, postoperative drainage, postoperative hospitalization time, and postoperative improvement in VAS. The mini-open pedicle screw technique could be applied in treatment of single-segment thoracolumbar fracture without neurologic injury and had advantages of less tissue trauma, short operative and rehabilitative time on the premise of guaranteed accuracy rate and no increased radiation exposure.
文摘We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the tho- racic or/and lumbar spine were alternately assigned to either the new free-hand or the conventional group. In the new free-hand technique group, preoperative computerized tomography (CT) images were used to calculate the targeted medial-lateral angle of each pedicle trajectory and the pedicle screw was inserted perpendicular to the corresponding supraspinal ligament. In the conventional technique group, the medial-lateral and cranial-caudal angle of each pedicle trajectory was determined by intraoperatively under fluoroscopic guidance. The accuracy rate of pedicle screw placement, the time of intraoperative fluoroscopy, the operating time and the amount of blood loss during operation were respectively compared. All screws were analyzed by using intraoperative ra- diographs, intraoperative triggered electromyography (EMG) monitoring data, postoperative CT data and clinical outcomes. The accuracy rate of pedicle screw placement in the new free-hand technique group and the conven- tional technique group was 96.3% and 94.2% (P 〈 0.05), respectively. The intraoperative fluoroscopy time of the new technique group was less than that of the conventional technique group (5.37 seconds vs. 8.79 seconds, P 〈 0.05). However, there was no statistical difference in the operating time and the amount of blood loss during op- eration (P 〉 0.05). Pedicle screw placement with the free-hand technique which keeps the screw perpendicular to the supraspinal ligament is an accurate, reliable and safe technique to treat simple fracture in the thoracic or lum- bar spine.
基金supported by the National Natural Science Foundation of China,No. 30973058,81171694Jiangsu Province Natural Science Foundation,No. BE2010743+2 种基金Jiangsu Graduate Student Innovation Project,No.CXZZ11_0721the Program for Development of Innovative Research Team in the First Affiliated Hospital of Nanjing Medical University,No. IRT-015a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The fast and accurate identification of nerve tracts is critical for successful nerve anastomosis. Taking advantage of differences in acetylcholinesterase content between the spinal ventral and dorsal roots, we developed a novel quartz crystal microbalance method to distinguish between these nerves based on acetylcholinesterase antibody reactivity. The acetylcholinesterase antibody was immobilized on the electrode surface of a quartz crystal microbalance and reacted with the acetylcholinesterase in sample solution. The formed antigen and antibody complexes added to the mass of the electrode inducing a change in frequency of the electrode. The spinal ventral and dorsal roots were distinguished by the change in frequency. The ventral and dorsal roots were cut into 1 to 2-mm long segments and then soaked in 250 pL PBS. Acetylcholinesterase antibody was immobilized on the quartz crystal microbalance gold electrode surface. The results revealed that in 10 minutes, both spinal ventral and dorsal roots induced a frequency change; however, the frequency change induced by the ventral roots was notably higher than that induced by the dorsal roots. No change was induced by bovine serum albumin or PBS. These results clearly demonstrate that a quartz crystal microbalance sensor can be used as a rapid, highly sensitive and accurate detection tool for the quick identification of spinal nerve roots intraoperatively.
基金This work is supported in part by the National Natural Science Foundation of China under contracts 61672242 and 61702199in part by China Spark Program under Grant 2015GA780002+1 种基金in part by The National Key Research and Development Program of China under Grant 2017YFD0701601in part by Natural Science Foundation of Guangdong Province under Grant 2015A030313413.
文摘Compressing encrypted images remains a challenge.As illustrated in our previous work on compression of encrypted binary images,it is preferable to exploit statistical characteristics at the receiver.Through this line,we characterize statistical correlations between adjacent bitplanes of a gray image with the Markov random field(MRF),represent it with a factor graph,and integrate the constructed MRF factor graph in that for binary image reconstruction,which gives rise to a joint factor graph for gray images reconstruction(JFGIR).By exploiting the JFGIR at the receiver to facilitate the reconstruction of the original bitplanes and deriving theoretically the sum-product algorithm(SPA)adapted to the JFGIR,a novel MRF-based encryption-then-compression(ETC)scheme is thus proposed.After preferable universal parameters of the MRF between adjacent bitplanes are sought via a numerical manner,extensive experimental simulations are then carried out to show that the proposed scheme successfully compresses the first 3 and 4 most significant bitplanes(MSBs)for most test gray images and the others with a large portion of smooth area,respectively.Thus,the proposed scheme achieves significant improvement against the state-of-the-art leveraging the 2-D Markov source model at the receiver and is comparable or somewhat inferior to that using the resolution-progressive strategy in recovery.
文摘BACKGROUND In order to improve risk stratification and clinical management of the pancreatic ductal adenocarcinoma(PDAC),the American Joint Committee on Cancer(AJCC)has published its eighth edition staging manual.Some major changes have been introduced in the new staging system for both T and N categories.Given the rarity of resectable disease,distal pancreatic cancer is likely underrepresented in the published clinical studies,and how the impact of the staging system actually reflects on to clinical outcomes remain unclear.AIM To validate the AJCC 8th edition of TNM staging in distal PDAC.METHODS A retrospective cohort study was performed in seven academic medical centers in the United States.Clinicopathological prognostic factors associated with progression-free survival(PFS)and overall survival(OS)were evaluated through univariate and multivariate analyses.RESULTS Overall,454 patients were enrolled in the study,and were divided into 2 subgroups:Invasive intraductal papillary mucinous neoplasms(IPMN)(115 cases)and non-IPMN associated adenocarcinoma(339 cases).Compared to invasive IPMN,non-IPMN associated adenocarcinomas are more common in relatively younger patients,have larger tumor size,are more likely to have positive lymph nodes,and are associated with a higher tumor(T)stage and nodal(N)stage,lymphovascular invasion,perineural invasion,tumor recurrence,and a worse PFS and OS.The cohort was predominantly categorized as stage 3 per AJCC 7th edition staging manual,and it’s more evenly distributed based on 8th edition staging manual.T and N staging of both 7th and 8th edition sufficiently stratify PFS and OS in the entire cohort,although dividing into N1 and N2 according to the 8th edition does not show additional stratification.For PDAC arising in IPMN,T staging of the 7th edition and N1/N2 staging of the 8th edition appear to further stratify PFS and OS.For PDAC without an IPMN component,T staging from both versions fails to stratify PFS and OS.CONCLUSION The AJCC 8th edition TNM staging system provides even distribution for the T staging,however,it does not provide better risk stratification than previous staging system for distal pancreatic cancer.
基金Supported by Jiangsu Agricultural Science and Technology Innovation Fund(CX(17)2023)Special Fund for Construction of Modern Agricultural Industrial Technology System(CARS-11-B-03)
文摘In recent years, sweet potato virus disease (SPVD) has severely affected the production of sweet potato in China. In order to select chemical agents to prevent sweet potato from being infected with SPVD, 14 pesticides were sprayed on the plants of sweet potato infected with SPVD, and the relative mRNA level of the viruses in the leaves and physiological indicators of sweet potato plants were detected. The results showed that after the application of most of the pesticides, the relative mRNA level of the two viruses that caused SPVD decreased, and the chlorophyll content and biomass of sweet potato infected with SPVD increased significantly or extremely significantly. Among the pesticides, BASF virus liquid, 0.1% physcion and Aolike powder for cucumber virus were proved to be the best, as the chlorophyll content and stem length of sweet potato increased significantly. The experiment indicated that the pesticides could reduce the harm of SPVD to sweet potato.
基金This work was supported by the National Natural Science Foundation of China(No.61601071,62071078)the National Key Research and Development Program of China(No.2019YFC1511300)+2 种基金the Natural Science Foundation of Chongqing(No.cstc2019jcyj-xfkxX0002)the Chongqing Entrepreneurship and Innovation Program for the Returned Overseas Chinese Scholars(No.cx2020095)the Graduate Scientific Research Innovation Project of Chongqing(No.CYS20251,CYS20253).
文摘As a promising technology to improve spectrum efficiency and transmission coverage,Heterogeneous Network(HetNet)has attracted the attention of many scholars in recent years.Additionally,with the introduction of the Non-Orthogonal Multiple Access(NOMA)technology,the NOMA-assisted HetNet cannot only improve the system capacity but also allow more users to utilize the same frequency band resource,which makes the NOMA-assisted HetNet a hot topic.However,traditional resource allocation schemes assume that base stations can exactly estimate direct link gains and cross-tier link gains,which is impractical for practical HetNets due to the impact of channel delays and random perturbation.To further improve energy utilization and system robustness,in this paper,we investigate a robust resource allocation problem to maximize the total Energy Efficiency(EE)of Small-Cell Users(SCUs)in NOMA-assisted HetNets under imperfect channel state information.By considering bounded channel uncertainties,the robust resource optimization problem is formulated as a mixed-integer and nonlinear programming problem under the constraints of the cross-tier interference power of macrocell users,the maximum transmit power of small base station,the Resource Block(RB)assignment,and the quality of service requirement of each SCU.The original problem is converted into an equivalent convex optimization problem by using Dinkelbach's method and the successive convex approximation method.A robust Dinkelbach-based iteration algorithm is designed by jointly optimizing the transmit power and the RB allocation.Simulation results verify that the proposed algorithm has better EE and robustness than the existing algorithms.
文摘Gasification unit is one of the key subsystems in the IGCC power system;the operating parameters of gasifier directly affect syngas quality and performance of whole IGCC system. The system model of gasification unit with coal water slurry gasifier was simulated and calculated using THERMOFLEX software, and the relations of oxygen coal ratio (Roc), water coal ratio (Rsc), gasification pressure, gasification temperature and cold gas efficiency were mostly researched. The results show that Roc and Rsc have effect of mutual restriction on gasification temperature, cold gas efficiency and syngas composition. Gasification pressure mainly determines the capacity of the gasifier, little effects on syngas composition.
基金supported by National Natural Science Foundation of China (31670170 and 31270209)by Ministry monomer, GAG facilitates Aβ fibrilization by pulling PrPC monomer to oligomerize
文摘A plethora of evidence suggests that protein misfolding and aggregation are underlying mechanisms of various neurodegenerative diseases,such as prion diseases and Alzheimer's disease(AD).Like prion diseases,AD has been considered as an infectious disease in the past decades as it shows strain specificity and transmission potential.Although it remains elusive how protein aggregation leads to AD,it is becoming clear that cellular prion protein(PrP^c)plays an important role in AD pathogenesis.Here,we briefly reviewed AD pathogenesis and focused on recent progresses how PrP^c contributed to AD development.In addition,we proposed a potential mechanism to explain why infectious agents,such as viruses,conduce AD pathogenesis.Microbe infections cause AD deposition and upregulation of PrP^c,which lead to high affinity binding between AD oligomers and PrP^c.The interaction between PrP^c and AP oligomers in turn activates the Fyn signaling cascade,resulting in neuron death in the central nervous system(CNS).Thus,silencing PrP^c expression may turn out be an effective treatment for PrP^c dependent AD.
文摘The management of oral and maxillofacial tissue defects caused by tumors,trauma,and congenital or acquired deformities has been a major challenge for surgeons over the last few decades.Autologous tissue transplantation,the gold standard of tissue reconstruction,is a valid method for repairing the oral and maxillofacial functions and aesthetics.However,several limitations hinder its clinical applications including complications of donor sites,limited tissue volume,and uncertain long-term outcomes.Adipose-derived mesenchymal stem cells(ADMSCs)widely exist in adipose tissue and can be easily obtained through liposuction.Like the bone marrow-derived mesenchymal stem cells(BMSCs),ADMSCs also have the multi-pluripotent potencies to differentiate into osteoblasts,chondrocytes,neurons,and myocytes.Therefore,the multilineage capacity of ADMSCs makes them valuable for cell-based medical therapies.In recent years,researchers have developed many candidates of ADMSCs-based biomaterial scaffolds to cater for the needs of oral and maxillofacial tissue engineering due to their superior performance.This review presents the advances and applications of ADMSCs-based biomaterial scaffolds,and explores their tissue engineering prospects in oral and maxillofacial reconstructions.
基金Project supported by the National Key Foundation for Exploring Scientific Instrument (No. 2013YQ03065102), the National Basic Research Program (973) of China (No. 2012CB316503), and the National Natural Science Foundation of China (Nos. 31327901, 61475010, 31361163004, and 61428501)
基金supported financially by the National Natural Science Foundation of China(Nos.51521001,51832003,51902236 and 31771032)。
文摘As one of the most delicate bioprocesses in nature,biosilicification is closely related to biosilica with various morphologies,and has provided abundant inspiration to materials synthesis.In the present study,to explore the biosilica formation process and fabricate silica with an exquisite microstructure for lithiumion battery(LIB)electrodes,a bacterial phage(M13)is used as a biotemplate to synthesize silica with diverse morphologies:cylinders,hexagonal prisms,assemblies of smaller cylinders and nanowires.A facile ethanol bath method is conducted to coat the nanowires with nitrogen-containing carbon and carbon-coated SiO_(2) nanowires with mesochannels(C@msSiO_(2) NWs)are first used as anode materials for LIBs.Attributed to the uniform carbon coating and parallel mesochannel structure,the electronic conductivity and capacity to accommodate volume variations were significantly improved.In the electrochemical perfo rmance test,the composites calcined at 750℃(C@msSiO_(2) NWs-750)show an impressive capacity of 653 mA h g^(-1) at a current density of 500 mA g^(-1) and stability(1000 cycles).In view of the electrochemical test outcomes,the prepa ration of a sophisticated structure with an outstanding potential is easily achieved via a biomimetic strategy.