Analysis of the Correlation among Three Oxygen Demand Indexes in Surface Water

Based on the monitoring data of chemical oxygen demand(COD),permanganate index(I Mn)and five-day biochemical oxygen demand(BOD 5)of surface water in Tongling section of Yangtze River,the linear relationship among the three indexes in the annual data analysis and the internal reasons,as well as the linear relationship and changes among the three indexes in different seasons were analyzed.The results reveal that in terms of the whole year,COD,I Mn and BOD 5 had a significant correlation and good linear relationship.The fitting slopes of the three indexes were 3.89 of COD/I Mn,4.39 of COD/BOD 5 and 1.16 of I Mn/BOD 5,respectively,which corresponded to the proportional relationship among the three indexes.From the perspective of seasonal changes,there was a very significant correlation between the three indexes in spring and summer.In autumn and winter,only COD and I Mn had a good correlation,but they had a poor correlation with BOD 5.

Integration of satellite remote sensing data in underground coal fire detection:A case study of the Fukang region,Xinjiang,China

Xinjiang in China is one of the areas worst affected by coal fires.Coal fires cannot only waste a large amount of natural resources and cause serious economic losses,but they also cause huge damage to the atmosphere,the soil,the surrounding geology,and the environment.Therefore,there is an urgent need to effectively explore remote sensing based detection of coal fires for timely understanding of their latest development trend.In this study,in order to investigate the distribution of coal fires in an accurate and reliable manner,we exploited both Landsat-8 optical data and Sentinel-1A synthetic aperture radar(SAR)images,using the generalized single-channel algorithm and the InSAR time-series analysis approach,respectively,for coal fire detection in the southern part of the Fukang region of Xinjiang,China.The generalized single-channel algorithm was used for land surface temperature information extraction.Meanwhile,the timeseries InSAR analysis technology was employed for estimating the surface micro deformation information,which was then used for building a band-pass filter.The suspected coal fire locations could then be established by a band-pass filtering operation on the obtained surface temperature map.Finally,the locations of the suspected coal fires were validated by the use of field survey data.The results indicate that the integration of thermal infrared remote sensing and radar interferometry technologies is an efficient investigation approach for coal fire detection in a large-scale region,which would provide the necessary spatial information support for the survey and control of coal fires.

Establishment of a selective evaluation method for DPP4 inhibitors based on recombinant human DPP8 and DPP9 proteins

Dipeptidyl peptidase 4(DPP4)is recognised as an attractive anti-diabetic drug target,and several DPP4 inhibitors are already on the market.As members of the same gene family,dipeptidyl peptidase 8(DPP8)and dipeptidyl peptidase 9(DPP9)share high sequence and structural homology as well as functional activity with DPP4.However,the inhibition of their activities was reported to cause severe toxicities.Thus,the development of DPP4 inhibitors that do not have DPP8 and DPP9 inhibitory activity is critical for safe anti-diabetic therapy.To achieve this goal,we established a selective evaluation method for DPP4 inhibitors based on recombinant human DPP8 and DPP9 proteins expressed by Rosetta cells.In this method,we used purified recombinant 120 kDa DPP8 or DPP9 protein from the Rosetta expression system.The optimum concentrations of the recombinant DPP8 and DPP9 proteins were 30 ng/mL and 20 ng/mL,respectively,and the corresponding concentrations of their substrates were both 0.2 mmol/L.This method was highly reproducible and reliable for the evaluation of the DPP8 and DPP9 selectivity for DPP4 inhibitor candidates,which would provide valuable guidance in the development of safe DPP4 inhibitors.

A critical review on the biomechanical study of cervical interbody fusion cage

Anterior Cervical Discectomy and Fusion(ACDF)is the preferred surgical method for the treatment of severe cervical degenerative disc disease with radiculopathy or myelopathy,of which the objectives are to restore the normal height of intervertebral space and cervical lordosis through the implantation of cervical interbody fusion cage.The biomechanical performance of a cervical interbody fusion cage,which plays a significant role in achieving the goals of ACDF,is influenced by multiple factors.In this paper,various studies focusing on the biomechanical performance of cervical interbody fusion cage are reviewed.Furthermore,the research methods,biomechanical evaluation parameters and data analysis methods of these research are analyzed in order to obtain a comprehensive understanding of the progress and limitations of research in this field.Although great progress has been made to clarify the biomechanical behaviors of cervical interbody fusion cage,there is still controversy regarding the issues such as the relative contribution of multiple factors to the performance of cage,the interactions among these factors,as well as whether the effects of factors change with the process of intervertebral osseointegration and so on.Thus,investigations are still needed to improve the comprehension of cervical interbody fusion cage biomechanically.

Effects of Geometrical Characteristics of Suture on Fracture Resistance of Walnut Shell

Nut shells have good impact and fracture resistance,but many kinds of nut shells have suture structures with low bonding strength.Therefore,the mechanism of impact and fracture resistance of nut shells as a whole is important to study,particularly given that sutures maintain low bonding strength.In this study,we investigated the effect of the geometrical characteristics of sutures(morphology,thickness,and number)on the overall fracture resistance of walnuts,based on mechanical tests of C-ring samples,microstructure analysis after cracking,quantitative analysis of suture geometric model,and numerical simulations.We found that the cracking of walnuts was mainly caused by tensile stress,and the bonding strength was approximately 2.48±0.64 MPa.We discovered that the thickness of the suture was 1.55±0.32 times thicker than the shell,which improved the fracture resistance ability by more than 28.4%.The undulating and inclined morphology of the walnut suture also increased the fracture force.Additionally,an appropriate suture number reduced the cracking of walnuts.In conclusion,our study sheds light on the physiological function of walnut sutures from a biomechanical perspective and provides useful references for designing fracture resistance measures in thin shell structures.

Biomimetic Water-Responsive Helical Actuators for Space-Efficient and Adaptive Robotic Grippers

Traditional robotic grippers encounter significant challenges when handling small objects in confined spaces,underscoring the need for innovative instruments with enhanced space efficiency and adaptability.Erodium cicutarium awns have evolved hygroresponsive helical deformation,efficiently driving seeds into soil crevices with limited space utilization.Drawing inspiration from this natural mechanism,we developed a biomimetic thin-walled actuator with water-responsive helical capabilities.It features a composite material structure comprising common engineering materials with low toxicity.Leveraging fused deposition modeling 3D printing technology and the composite impregnation process,the actuator’s manufacturing process is streamlined and cost-effective,suitable for real-world applications.Then,a mathematical model is built to delineate the relationship between the biomimetic actuator’s key structural parameters and deformation characteristics.The experimental results emphasize the actuator’s compact dimension(0.26 mm thickness)and its capability to form a helical tube under 5 mm diameter within 60 s,demonstrating outstanding space efficiency.Moreover,helical characteristics and stiffness of the biomimetic actuators are configurable through precise modifications to the composite material structure.Consequently,it is capable of effectively grasping an object smaller than 3 mm.The innovative mechanism and design principles hold promise for advancing robotic technology,particularly in fields requiring high space efficiency and adaptability,such as fine tubing decongestion,underwater sampling,and medical endoscopic surgery.