Multi-parametric quantitative microvascular imaging with optical-resolution photoacoustic microscopy in vivo

Many diseases involve either the formation of new blood vessels (e.g., tumor angiogenesis) or the damage of existing ones (e.g., diabetic retinopathy) at the microcirculation level. Optical-resolution photoacoustic microscopy (OR-PAM), capable of imaging microvessels in 3D in vivo down to individual capillaries using endogenous contrast, has the potential to reveal microvascular information critical to the diagnosis and staging of microcirculation-related diseases. In this study, we have developed a dedicated microvascular quantification (MQ) algorithm for OR-PAM to automatically quantify multiple microvascular morphological parameters in parallel, including the vessel diameter distribution, the microvessel density, the vascular tortuosity, and the fractal dimension. The algorithm has been tested on in vivo OR-PAM images of a healthy mouse, demonstrating high accuracy for microvascular segmentation and quantification. The developed MQ algorithm for OR-PAM may greatly facilitate quantitative imaging of tumor angiogenesis and many other microcirculation related diseases in vivo

Multi-parametric quantitative microvascular imaging with optical-resolution photoacoustic microscopy in vivo

Many diseases involve either the formation of new blood vessels (e.g., tumor angiogenesis) or the damage of existing ones (e.g., diabetic retinopathy) at the microcirculation level. Optical-resolution photoacoustic microscopy (OR-PAM), capable of imaging microvessels in 3D in vivo down to individual capillaries using endogenous contrast, has the potential to reveal microvascular information critical to the diagnosis and staging of microcirculation-related diseases. In this study, we have developed a dedicated microvascular quantification (MQ) algorithm for OR-PAM to automatically quantify multiple microvascular morphological parameters in parallel, including the vessel diameter distribution, the microvessel density, the vascular tortuosity, and the fractal dimension. The algorithm has been tested on in vivo OR-PAM images of a healthy mouse, demonstrating high accuracy for microvascular segmentation and quantification. The developed MQ algorithm for OR-PAM may greatly facilitate quantitative imaging of tumor angiogenesis and many other microcirculation related diseases in vivo

Reinforcement Mechanism and Erosion Resistance of Loess Slope Using Enzyme Induced Calcite Precipitation Technique

The disaster of loess slope seriously threatened the safety of people and property. Enzyme Induced Calcite Precipitation (EICP) was demonstrated as an environmentally friendly soil improvement method. However, few studies have focused on the improvement effect of EICP on loess slopes. In this study, a series of tests were conducted to investigate the effect of EICP and added either basalt fiber (BF) to the loess or polyvinyl acetate emulsion (PVAC) to the solution on the erosion resistance of loess slopes. The results showed that all of the EICP, EICP-BF, and EICP-PVAC treatments could improve surface strength (SS). The addition of 50 g/L PVAC achieved high SS because the network structure formed by PVAC promoted the affixation of CaCO3. The thickness of the crust layer decreased with the increasing BF content or PVAC concentration. With the increasing number of EICP treatment cycles, the CaCO3 content increased progressively, but the increase rate decreased. For rainfall erosion, the time until erosion occurred was delayed and the stability was improved for loess slopes treated with EICP, EICP-BF, and EICP-PVAC. The high erosion resistance of loess slopes treated with EICP-0.5% BF, EICP-30 g/L PVAC, and EICP-50 g/L PVAC was attributed to the stable spatial structure formed by CaCO3 precipitation and the additional cementation provided by high BF content and PVAC concentration. The addition of 0.5% BF effectively inhibited the development of surface cracks in loess slope after dry–wet cycles. With the increasing number of dry–wet cycles, the accumulative loess loss weight of slopes treated with various methods increased gradually. Among all treatment methods, the number of dry–wet cycles had less effect on EICP-30 g/L PVAC treated loess slopes. This study provided guidance for loess slopes prevention

Gradual Reliability Sensitivity Analysis of Mechanical Part Considering Preventive Maintenance

A lot of mechanical parts are subject to failure due to the deterioration. Usually the preventive maintenance is taken to ensure the safety and reliability. Therefore, it is very important to study the gradual reliability design of the mechanical part for improving the gradual reliability of the mechanical system under the condition of considering the preventive maintenance. Beta distribution is employed to describe the randomness of the mechanical part state after the preventive maintenance. The deterioration process of the mechanical part is modeled using the nonstationary Gamma process. The gradual reliability model before the first preventive maintenance is proposed according to the gradual failure principle and using the initial state distribution and the properties of Gamma process. Then, the gradual reliability model between any two times of preventive maintenance is also derived. Subsequently, the sensitivity equations of the proposed gradual reliability model to each parameter are given. The application process and practicality of the proposed approach are described by a numerical example. This work solved the problem where the maintenance has not been well considered in the reliability design of the mechanical part and contributed to the theory and method of improving the safety and reliability operation of the mechanical system

METHOD AND FINITE ELEMENT ANALYSIS FOR THE COMPRESSION INSTABILITY ULTIMATE LOAD OF A Z-SHAPED STIFFENED-WELED PLATE

Object of study was the large Z shaped stiffened-welded plate,combined with theoretical analysis and finite element simulation of Abaqus researched the compression instability ultimate load,to provide theory and simulation for the application of large welded plate,save the test cost and improve efficiency. The theory studied the relationship between effective width and radius of inertia,calculation of the average load as skin with truss had different material. In the simulation of analysis,ultimate load was determined by extracting the extreme value of the load proportion factor（ LPF）. For improving the accuracy of the simulation,according to the strength of the welding seam with the cloud image judged the welding sequence,studied on the variation of ultimate load in welding,to determine the limit load range. Theoretical and the simulation value compared with the experiment. Influence of the elastic modulus of material on the overall ultimate load was analyzed,by the result of the analysis,the modulus of the long truss material is more conductive to improve the ultimate load

Characteristics of the mitochondrial genome of Qinling zokor (Eospalax rufescens)

We report the complete mitochondrial genome for the Eospalax rufescens, a typical subterranean rodent species and endemic in China. The resulting E. rufescens mitogenome is 16,355 bases in size, containing 13 protein-coding genes (PCGs), 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and 1 noncoding control region (D-loop). The base compositions present highly biased toward A + T nucleotides. Moreover, twelve of all 13 PCGs initiated with ATN start codon, whereas ND1 began with GTG start codon. Stop codons in 13 PCGs were all typical types except incomplete stop codon T for ND4. We further provide a Maximum Likelihood phylogenetic tree showing relationships among E. rufescens and other common subterranean rodents in family Spalacidae