Multi-Slice Computer Tomography Dynamic Enhanced Expression and Clinical Significance of Hepatic Perfusion Abnormalities

Objective: To investigate the imaging features and clinical significance of the dynamic enhanced CT perfusion of the liver. Method: 112 cases of hepatic perfusion disorders were collected, including 22 cases of hepatocellular carcinoma with tumor thrombus, 12 cases of bile duct carcinoma, 16 cases of cholangitis, 31 cases of hemangioma, 10 cases of liver cirrhosis and liver laceration injury in 5 cases, 16 cases of liver abscess, all cases were surgically or clinically confirmed. All cases were performed with three phase enhanced scanning, and the images were loaded into the PACS system. Results: In 26 cases, 76 cases with patchy enhancement around the focus were shown in 10 cases with patchy enhancement. Arterial phase was in 47 cases, 12 cases with high perfusion, and 53 cases with high perfusion. Conclusion: Correct understanding of liver perfusion abnormalities in the diagnosis of lesions and reduce the true extent of the lesion is important

Assembly of a high-dielectric constant thin TiOX layer directly on H-terminated semiconductor diamond

A high-dielectric constant (high-k) TiOx thin layer was fabricated on hydrogen-terminated diamond (H-diamond) surface by low temperature oxidation of a thin titanium layer in ambient air. The metallic titanium layer was deposited by sputter deposition. The dielectric constant of the resultant TiOx was calculated to be around 12. The capacitance density of the metal-oxide-semiconductor (MOS) based on the TiOx/H-diamond was as high as 0.75 µF/cm2 contributed from the high-k value and the very thin thickness of the TiOx layer. The leakage current was lower than 10-13 A at reverse biases and 10-7A at the forward bias of -2 V. The MOS field-effect transistor based on the high-k TiOx/H-diamond was demonstrated. The utilization of the high-k TiOx with a very thin thickness brought forward the features of an ideally low subthreshold swing slope of 65 mV per decade and improved drain current at low gate voltages. The advantages of the utilization high-k dielectric for diamond MOSFETs are anticipated

Lack of association between polymorphisms of MASP2 and susceptibility to SARS coronavirus infection

<p>Abstract</p> <p>Background</p> <p>The pathogenesis of severe acute respiratory disease syndrome (SARS) is not fully understood. One case-control study has reported an association between susceptibility to SARS and <it>mannan-binding lectin </it>(<it>MBL</it>) in China. As the downstream protein of <it>MBL</it>, variants of the <it>MBL</it>-associated serine protease-2 (<it>MASP2</it>) gene may be associated with SARS coronavirus (SARS-CoV) infection in the same population.</p> <p>Methods</p> <p>Thirty individuals with SARS were chosen for analysis of <it>MASP2 </it>polymorphisms by means of PCR direct sequencing. Tag single nucleotide polymorphisms (tagSNPs) were chosen using pairwise tagging algorithms. The frequencies of four tag SNPs (rs12711521, rs2261695, rs2273346 and rs7548659) were ascertained in 376 SARS patients and 523 control subjects, using the Beckman SNPstream Ultra High Throughput genotyping platform.</p> <p>Results</p> <p>There is no significant association between alleles or genotypes of the <it>MASP2 </it>tagSNP and susceptibility to SARS-CoV in both Beijing and Guangzhou populations. Diplotype (rs2273346 and rs12711521)were analyzed for association with susceptibility to SARS, no statistically significant evidence of association was observed. The Beijing and Guangzhou sample groups were homogeneous regarding demographic and genetic parameters, a joined analysis also showed no statistically significant evidence of association.</p> <p>Conclusion</p> <p>Our data do not suggest a role for <it>MASP2 </it>polymorphisms in SARS susceptibility in northern and southern China.</p

Improved SnO2 Electron Transport Layers Solution-Deposited at Near Room Temperature for Rigid or Flexible Perovskite Solar Cells with High Efficiencies

Electron transport layer (ETL) is a functional layer of great significance for boosting the power conversion efficiency (PCE) of perovskite solar cells (PSCs). To date, it is still a challenge to simultaneously reduce the surface defects and improve the crystallinity in ETLs during their low-temperature processing. Here, a novel strategy for the mediation of in situ regrowth of SnO2 nanocrystal ETLs is reported: introduction of controlled trace amounts of surface absorbed water on the fluorinated tin oxide (FTO) or indium-tin oxide (ITO) surfaces of the substrates using ultraviolet ozone (UVO) pretreatment. The optimum amount of adsorbed water plays a key role in balancing the hydrolysis-condensation reactions during the structural evolution of SnO2 thin films. This new approach results in a full-coverage SnO2 ETL with a desirable morphology and crystallinity for superior optical and electrical properties, as compared to the control SnO2 ETL without the UVO pretreatment. Finally, the rigid and flexible PSC devices based on the new SnO2 ETLs yield high PCEs of up to 20.5% and 17.5%, respectively

Synthesis, characterization and photodynamic therapy properties of an octa-4-tert-butylphenoxy-substituted phosphorus (V) triazatetrabenzcorrole

A novel octa-4-tert-butylphenoxy-substituted phosphorus(V) triazatetrabenzcorrole (PVTBC), has been synthesized and characterized by MALDI-TOF MS and NMR, FT-IR and MCD spectroscopy. The fluorescence emission spectrum was used to determine the fluorescence quantum yield and the quantum yield for singlet oxygen generation was calculated by using 1,3-diphenylisobenzofuran as a scavenger. The photocytoxicity against U87MG cells was measured. The results indicated that PVTBC is potentially useful as an NIR region photosensitizer for photodynamic therapy (PDT)

DT-driven memory cutting control method using VR instruction of boom-type roadheader

Aiming at the problems of low intelligence of current tunneling equipment, difficulty in describing over-excavation, under-excavation and abnormal collision in tunneling process, and difficulty in adapting traditional automatic cutting and memory cutting technology to complex geological conditions, a digital twin-driven virtual teaching memory cutting control method for cantilever roadheader is proposed. By analyzing the research situation of digital twin technology in the field of intelligent coal mining, the overall scheme of memory cutting control system of cantilever roadheader driven by digital twin is designed, and the key technology of memory cutting of cantilever roadheader under complex working conditions is studied. Firstly, the characteristics of digital twin and virtual reality technology are fully utilized to study the virtual teaching strategy under complex working conditions. Based on the Unity3D platform, the virtual twin model of the working face and equipment with the same size of the corresponding entity, the kinematics model of the cutting unit and the virtual collision detection model are established. The virtual model movement is controlled through the intelligent interactive interface at the virtual end, and the teaching trajectory is designed and optimized according to the worker’s experience, so that it can be used as the target expected trajectory of trajectory tracking to make up for the excessive dependence on the worker’s experience caused by the traditional underground manual teaching due to the harsh working conditions. Secondly, in order to improve the quality of section forming, the control method of teaching trajectory tracking and reproduction in memory automatic cutting stage is studied. The dynamic model of cutting part is established by Lagrange method, and the tracking control accuracy of end effector to teaching trajectory is improved by combining iterative learning with sliding mode control. Finally, the simulation control platform of the memory cutting of the cantilever roadheader is built. Through the real-time data transmission and interaction between the virtual space and the physical space and between the modules, the three-dimensional visual simulation of the memory cutting virtual teaching and trajectory tracking control process is completed in the virtual space, and then the memory automatic cutting trajectory tracking control command is generated and sent to the end effector of the physical entity of the cantilever roadheader to drive it to carry out the section forming cutting according to the teaching trajectory. At the same time, the physical sensor collects the pose data of the cantilever roadheader fuselage and the cutting arm, and reversely drives the virtual model to move synchronously. The closed-loop control of robot virtual model and physical entity is realized. On this basis, the virtual and real synchronization of the system, the motion consistency between the virtual prototype and the physical prototype, and the trajectory tracking and reproduction control accuracy are verified. The experimental results show that the system data transmission delay is low, which can ensure the virtual and real consistency and synchronization, and the trajectory tracking control accuracy meets the actual use requirements. This method provides a new idea for memory cutting and intelligent control of tunneling equipment

On the Origin of Tibetans and Their Genetic Basis in Adapting High-Altitude Environments

Since their arrival in the Tibetan Plateau during the Neolithic Age, Tibetans have been well-adapted to extreme environmental conditions and possess genetic variation that reflect their living environment and migratory history. To investigate the origin of Tibetans and the genetic basis of adaptation in a rigorous environment, we genotyped 30 Tibetan individuals with more than one million SNP markers. Our findings suggested that Tibetans, together with the Yi people, were descendants of Tibeto-Burmans who diverged from ancient settlers of East Asia. The valleys of the Hengduan Mountain range may be a major migration route. We also identified a set of positively-selected genes that belong to functional classes of the embryonic, female gonad, and blood vessel developments, as well as response to hypoxia. Most of these genes were highly correlated with population-specific and beneficial phenotypes, such as high infant survival rate and the absence of chronic mountain sickness

Numerical modeling of tunneling effect on buried pipelines

The underground space in urban areas is frequently congested with utilities, including pipelines and conduits, that are affected by underground construction, e.g., tunneling. This paper carries out finite element (FE) analyses to investigate the effects of tunneling-induced ground movement on pipelines, with special attention to the different soil responses to uplift and downward pipe-soil relative movements. A series of numerical parametric studies with 900 FE simulation runs in total is performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, pipe burial depth, and soil properties that are typical for utility pipelines and tunnel construction in urban areas. The results are summarized in a dimensionless plot of relative pipe-soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) to directly assess the tunneling-induced risk to pipelines. The FE results and dimensionless plot are validated against field and centrifuge test results reported in the literature. Effect of pipeline orientation with respect to the tunnel centerline is explored. It might be unconservative if design analysis only considers the case that the pipeline is perpendicular to the tunnel centerline

Buried pipeline responses to ground displacements induced by adjacent static pipe bursting

To minimize disruptions of economic and social activities on the ground surface in urban areas, trenchless techniques such as pipe bursting are often considered for underground pipeline construction, rehabilitation, and renewal of existing utility services. Pipe bursting, however, inevitably induces outward displacements of surrounding soil, and subsequently leads to potential damages to adjacent structures and utilities. This paper carries out finite element (FE) analyses to investigate effects of the static pipe bursting-induced ground displacements on adjacent pipelines. In total 760 FE parametric studies are performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, and soil properties that are typical of utility pipelines and pipe bursting in urban areas. The FE parametric results are summarized in a dimensionless plot of relative pipe-soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) directly evaluate pipeline responses to adjacent pipe bursting. A worked example is provided to illustrate usage of the dimensionless plot. It is further found that the pipe-soil interaction is similar for pipe bursting and tunneling, and the effects of both pipe bursting and tunneling on adjacent pipelines can be assessed using a unified dimensionless plot. Effects of the intersection angle between the pipe bursting centerline and adjacent pipeline are explored. The pipe responses are shown to be underestimated or unconservative when only the perpendicular case is considered in the analysis