Application Research of PETD Combined with MRI Nerve Root Water Imaging in the Minimally Invasive Treatment of LDH

Objective: This study aims to evaluate the safety and efficacy of PETD combined with nerve root water imaging of MRI for the treatment of lumbar disc herniation. Methods: A retrospective review was performed on 62 patients with lumbar disc herniation from March 2019 to March 2021. The study included an experimental group of 30 patients and a control group of 32 patients. The experimental group underwent PETD combined with nerve root water imaging of MRI, while the control group received traditional PETD treatment. The visual analogue scoring method (VAS score), and JOA lumbar spine function score before and after surgery were compared between the two groups, and efficacy was assessed and compared using the MacNab score. Results: The mean operation time was significantly reduced in the experimental group (56.43 ±10.40 minutes) compared to the control group (65.69 ±14.12 minutes). The VAS score was compared between the two groups with preoperative (p = 0.624), one month after surgery (p = 0.325), three months after surgery (p = 0.676), one year after surgery (p = 0.341);The JOA score was compared between the two groups with preoperative (p = 0.961), one month after the surgery (p = 0.266), three months after surgery (p = 0.185), one year after surgery (p = 0.870), they were no significant statistical difference;The efficacy evaluation of the last follow-up Macnab showed that all the 30 patients in the experimental group were excellent, 31 of 32 patients in the control group were excellent, 1 case was good;There was no statistical difference in the comparison between the two groups (p > 0.05). Conclusion: The study concludes that the combined approach of PETD with nerve root water imaging of MRI is a safe, effective, and more efficient alternative to conventional PETD for treating lumbar disc herniation.

Effects of probiotics on nonalcoholic fatty liver disease:A meta-analysis

AIM:To investigate the relationship between the gutliver axis and nonalcoholic fatty liver disease(NAFLD),we performed a meta-analysis to evaluate the effects of probiotic therapy in NAFLD.METHODS:We searched PubMed,Medline,Embase,Web of Science,the Cochrane Library and Chinese Biomedicine Database for all relevant randomized controlled trials on probiotics in patients with NAFLD/nonalcoholic steatohepatitis(NASH).A statistical analysis was performed using RevMan 5.0 software.RESULTS:Four randomized trials involving 134 NAFLD/NASH patients were included.The results showed that probiotic therapy signifcantly decreased alanine aminotransferase(ALT),aspartate transaminase(AST),total-cholesterol(T-chol),high density lipoprotein(HDL),tumor necrosis factor(TNF)-αand homeostasis model assessment of insulin resistance(HOMAIR)[ALT:weighted mean difference(WMD)-23.71,95%CI:-33.46--13.95,P<0.00001;AST:WMD-19.77,95%CI:-32.55--7.00,P=0.002;T-chol:WMD-0.28,95%CI:-0.55--0.01,P=0.04;HDL:WMD-0.09,95%CI:-0.16-0.01,P=0.03;TNF-α:WMD-0.32,95%CI:-0.48--0.17,P<0.0001;HOMA-IR:WMD-0.46,95%CI:-0.73--0.19,P=0.0008].However,the use of probiotics was not associated with changes in body mass index(BMI),glucose(GLU)and low density lipoprotein(LDL)(BMI:WMD 0.05,95%CI:-0.18-0.29,P=0.64;GLU:WMD 0.05,95%CI:-0.25-0.35,P=0.76;LDL:WMD-0.38,95%CI:-0.78-0.02,P=0.06).CONCLUSION:Probiotic therapies can reduce liver aminotransferases,total-cholesterol,TNF-αand improve insulin resistance in NAFLD patients.Modulation of the gut microbiota represents a new treatment for NAFLD.

Risk factors for alcohol-related liver injury in the island population of China: A population-based case-control study

AIM:To investigate the association of alcohol dose, duration of drinking and obesity with abnormal alcohol-related liver injury indicators, the prevalence of alcohol-related liver injury in the island population of China.METHODS:Randomized multistage stratified cluster sampling from the island population of China was used in the population-based case-control study. Then interview, physical examination, laboratory assessments and ultrasonography were done. RESULTS:Daily alcohol intake ≥ 20 g, duration of drinking ≥ 5 years and obesity were closely related to alcohol-related liver injury (P < 0.05). The odds-ratio (OR) (95% CI) was 1.965 (1.122-3.442), 3.412 (1.789-6.507) and 1.887 (1.261-2.824), respectively. The prevalence rate of alcohol-related liver injury in ≥ 20 g daily alcohol intake group and < 20 g daily alcohol intake group was 37.14% and 12.06%, respectively. The prevalence rate of alcohol-related liver injury in ≥ 5 years drinking group and < 5 years drinking group was 34.44% and 8.53%, respectively. No significant dose-response relation was found between daily alcohol intake and abnormal alcohol-related liver injury indicators as well as between duration of drinking and abnormal alcohol-related liver injury indicators. There was no significant difference in the prevalence of alcohol-related liver injury between beer drinking group and yellow rice wine drinking group, hard liquor drinking group, multiple drinking group.CONCLUSION:The risk threshold of daily alcohol intake is 20 g and duration of drinking inducing alcohol-related liver injury 5 years in the island population of China. Liver injury induced by obesity should be concerned.

Potential role of Helicobacter pylori infection in nonalcoholic fatty liver disease

Accumulating evidence has implicated Helicobacter pylori(H.pylori)infection in extragastrointestinal diseases,including obesity,type 2 diabetes mellitus,cardiovascular disease,and liver disease.Recently,there has been a special focus on H.pylori infection as a risk factor for the development of nonalcoholic fatty liver disease(NAFLD).NAFLD is currently considered to be the most common liver disorder in western countries,and is rapidly becoming a serious threat to public health.The mechanisms of pathogenesis underlying NAFLD remain unclear at present and therapeutic options are limited.The growing awareness of the role of H.pylori in NAFLD is thus important to aid the development of novel intervention and prevention strategies,because the eradication of H.pylori is easy and much less expensive than long-term treatment of the other risk factors.H.pylori infection is involved in the pathogenesis of insulin resistance(IR),which is closely linked with NAFLD.It provides a new insight into the pathogenesis of NAFLD.This review probes the possible relationship between H.pylori and NAFLD,from the perspective of the potential mechanism of how H.pylori infection brings about IR and other aspects concerning this correlation.

Helicobacter pylori infection is associated with gallstones: Epidemiological survey in China

AIM: To elucidate the prevalence and risk factors for gallstones, primarily focusing on Helicobacter pylori(H. pylori) infection. METHODS: A total of 10016 Chinese subjects, who had undergone physical examination, fasting 13 C urea breath test and abdominal ultrasonography, had sufficient blood test data, and had finished a questionnaire, were included in this cross-sectional study. Participants(n = 1122) who had previous eradication of H. pylori were studied separately. RESULTS: Gallstones were discovered in 9.10% of men and 8.58% of women, with no significant sex difference. Multivariate analyses displayed that age, aspartate aminotransferase, total cholesterol, H. pylori infection, hepatitis C virus(HCV) infection, and fattyliver had a significant association with gallstones(P < 0.05). Successive multiple logistic regression analysis including index of odds ratio(OR) and standardized coefficient(β) indicated that older age(OR/β = 1.056/0.055), H. pylori infection(OR/β = 1.454/0.109), HCV infection(OR/β = 1.871/0.123), and fatty liver(OR/β = 1.947/0.189) had a significant positive association with gallstones. After age stratification, H. pylori infection and fatty liver still had a significant positive association with gallstones in any age-specific groups, whereas HCV infection had a significant positive association in patients aged > 40 years. The prevalence of gallstones among H. pylori-positive, H. pylori-eradicated, and H. pylori-negative subjects was 9.47%, 9.02%, and 8.46%, respectively. The matched analysis showed that gallstones among H. pylori eradicated subjects was significantly lower compared with H. pylori-positive subjects(P < 0.05).CONCLUSION: H. pylori infection and fatty liver have a significant positive association with gallstones. H. pylori eradication may lead to prevention of gallstones.

Construction of a convolutional neural network classifier developed by computed tomography images for pancreatic cancer diagnosis

BACKGROUND Efforts should be made to develop a deep-learning diagnosis system to distinguish pancreatic cancer from benign tissue due to the high morbidity of pancreatic cancer.AIM To identify pancreatic cancer in computed tomography(CT)images automatically by constructing a convolutional neural network(CNN)classifier.METHODS A CNN model was constructed using a dataset of 3494 CT images obtained from 222 patients with pathologically confirmed pancreatic cancer and 3751 CT images from 190 patients with normal pancreas from June 2017 to June 2018.We established three datasets from these images according to the image phases,evaluated the approach in terms of binary classification(i.e.,cancer or not)and ternary classification(i.e.,no cancer,cancer at tail/body,cancer at head/neck of the pancreas)using 10-fold cross validation,and measured the effectiveness of the RESULTS The overall diagnostic accuracy of the trained binary classifier was 95.47%,95.76%,95.15%on the plain scan,arterial phase,and venous phase,respectively.The sensitivity was 91.58%,94.08%,92.28%on three phases,with no significant differences(χ2=0.914,P=0.633).Considering that the plain phase had same sensitivity,easier access,and lower radiation compared with arterial phase and venous phase,it is more sufficient for the binary classifier.Its accuracy on plain scans was 95.47%,sensitivity was 91.58%,and specificity was 98.27%.The CNN and board-certified gastroenterologists achieved higher accuracies than trainees on plain scan diagnosis(χ2=21.534,P<0.001;χ2=9.524,P<0.05;respectively).However,the difference between CNN and gastroenterologists was not significant(χ2=0.759,P=0.384).In the trained ternary classifier,the overall diagnostic accuracy of the ternary classifier CNN was 82.06%,79.06%,and 78.80%on plain phase,arterial phase,and venous phase,respectively.The sensitivity scores for detecting cancers in the tail were 52.51%,41.10%and,36.03%,while sensitivity for cancers in the head was 46.21%,85.24%and 72.87%on three phases,respectively.Difference in sensitivity for cancers in the head among the three phases was significant(χ2=16.651,P<0.001),with arterial phase having the highest sensitivity.CONCLUSION We proposed a deep learning-based pancreatic cancer classifier trained on medium-sized datasets of CT images.It was suitable for screening purposes in pancreatic cancer detection.

High-efficiency and pollution-controlling in-situ gasification chemical looping combustion system by using CO_2 instead of steam as gasification agent

Using CO_2 as gasification agent instead of steam in in-situ coal gasification chemical looping combustion(i G-CLC)power plant can eliminate energy consumption for steam generation, thus obtaining higher system efficiency. In this work, a comparative study of iG-CLC power plant using steam and CO_2 as gasification agent is concentrated on. The effects of steam to carbon ratio(S/C) and CO_2 to carbon ratio(CO_2/C) on the fuel reactor temperature,char conversion, syngas composition and CO_2 capture efficiency are separately investigated. An equilibrium carbon conversion of 88.9% is achieved in steam-based case as S/C ratio increases from 0.7 to 1.1, whereas a maximum conversion of 84.2% is obtained in CO_2-based case with CO_2/C ranging from 0.7 to 1.1. Furthermore the effects of oxygen carrier to fuel ratio(φ) on system performances are investigated. Increasing φ from 1.0 to1.4 helps to achieve char conversion from 75.9% to 88.9% in steam-based case, by contrast the char conversion can achieve 66.3%–84.2% in CO_2-based case within the same φ range. In terms of iG-CLC power plant, recycling partial CO_2 to the fuel reactor improves the overall performance. Approximately 3.9% of net power efficiency are increased in CO_2-based plant, from steam-based plant. Higher CO_2 capture efficiency and lower CO_2 emission rate are observed in CO_2-gasified iG-CLC power plant, expecting to be 90.63% and 85.18 kg·MW-1·h-1,respectively.

Optical Pulling Force in Non-Paraxial Bessel Tractor Beam Generated with Polarization-Insensitive Metasurface

Tractor beams,able to produce optical pulling forces(OPFs)on particles,are attracting increasing attention.Here,non-paraxial Bessel tractor beams are generated using polarization-insensitive metasurfaces.OPFs are found to exert on dielectric particles with specific radii at the axes of the beams.The strengths of the OPFs depend on the radii of the particles,which provides the possibility of sorting particles with different sizes.For the OPFs,the radius ranges of particles vary with the polarization states or topological charges of the incident beams.The change of polarizations can provide a switch between the pulling and pushing forces,which offers a new way to realize dynamic manipulation of particles.The change of topological charges leads to disjoint radii ranges for the OPFs exerting on particles,which provides the possibility of selective optical separation.Moreover,we study the behaviors of particles in the tractor beams.The simulation results reveal that linearly or circularly polarized tractor beams can pull particles a sufficient distance towards the light source,which verifies the feasibility of separating particles.

Evolution of the microstructure and solute distribution of Sn-10wt% Bi alloys during electromagnetic field-assisted directional solidification

The effects of forced flows at different velocities on microstructure and solute distribution during the directional solidification of Sn-10 wt% Bi alloys under a simultaneous imposition of a transverse static magnetic field(TSMF) and an external direct current(DC) have been investigated experimentally and numerically. The experimental results show that the solid-liquid interface will gradually become sloping with the increase of the forced flow velocity when the thermoelectric magnetic convection(TEMC)dominates the forced flow at solidification front. However, the interface will gradually become planar as the flow velocity further increases when the electromagnetic convection(EMC) dominates the forced flow. Moreover, when the flow velocity gradually increases, the primary dendrite spacing decreases from384 to 105 μm accordingly. The simulation results show that the solute distribution at the two sides of the sample can be significantly changed by the forced flow at solidification front. The rejected solute will be unidirectionally transported to one side of the sample along the TEMC(a low-velocity forced flow),thereby causing the formation of a sloping interface. However, the rejected solute will be returned back along the EMC(a higher-velocity force flow), which results in a planar interface. Furthermore, the solute content at the two sides of the sample under the forced flows at different velocities was measured. The results are in good agreement with the simulation results, which shows that the solute content difference between the two sides of the sample reaches the maximum when a 0.5 T TSMF is applied, while the solute content difference decreases to zero with a simultaneous application of a 0.5 T TSMF and a 1.6 × 10~5 A/m^2 external DC.

Analysis of an improved workflow of endoscope reprocessing for bedside endoscopic diagnosis and treatment on COVID-19 patients

Severe cases infected with the coronavirus disease 2019(COVID-19),named by the World Health Organization(WHO)on Feb.11,2020,tend to present a hypercatabolic state because of severe systemic consumption,and are susceptible to stress ulcers and even life-threatening gastrointestinal bleeding.Endoscopic diagnosis and treatment constitute an irreplaceable part in the handling of severe COVID-19 cases.Endoscopes,as reusable precision instruments with complicated structures,require more techniques than other medical devices in cleaning,disinfection,sterilization,and other reprocessing procedures.From 2016 to 2019,health care-acquired infection caused by improper endoscope reprocessing has always been among the top 5 on the list of top 10 health technology hazards issued by the Emergency Care Research Institute.Considering the highly infective nature of COVID-19 and the potential aerosol contamination therefrom,it is of pivotal significance to ensure that endoscopes are strictly reprocessed between uses.In accordance with the national standard"Regulation for Cleaning and Disinfection Technique of Flexible Endoscope(WS507-2016),"we improved the workflow of endoscope reprocessing including the selection of chemicals in an effort to ensure quality control throughout the clinical management towards COVID-19 patients.Based on the experience we attained from the 12 severe COVID-19 cases in our hospital who underwent endoscopy 23 times in total,the article provides an improved version of endoscopic reprocessing guidelines for bedside endoscopic diagnosis and treatment on COVID-19 patients for reference.

A precipitate-free AlCoFeNi eutectic high-entropy alloy with strong strain hardening

Over recent years,eutectic high-entropy alloys(EHEAs)have intrigued substantial research enthusiasms due to their good castability as well as balanced strength-ductility synergy.In this study,a bulk cast Al_(19.25)Co_(18.86)Fe_(18.36)Ni_(43.53)EHEA is developed with fine in-situ lamellar eutectics.The eutectics comprise alternating ordered face-centered-cubic(L1_(2))and ordered body-centered-cubic(B2)phases with semicoherent interfaces.The resulting microstructure resembles that of most reported as-cast EHEAs,but the B2 lamellae are devoid of nano-precipitates because of the Cr-element removal in current tailored eutectic composition.Surprisingly,the B2 lamellae still feature much higher deformation resistance than the L1_(2) lamellae,so that less lattice defects are detected in the B2 lamellae until the fracture.More interestingly,in the L1_(2) lamellae we identify a dynamic microstructure refinement that correlates to extraordinary strain hardening in tension.The precipitate-free EHEA consequently shows excellent tensile ductility of~10%and high ultimate strength up to~956 MPa.

Effect of axial static magnetic field on cleanliness and microstructure in magnetically controlled electroslag remelted bearing steel

The effect of the axial static magnetic field(ASMF)on cleanliness and microstructure in magnetically controlled electroslag remelted GCr15 bearing steel ingots was investigated experimentally.The results show that a magnetically controlled spin-vibration induced by the interaction of the ASMFs and the remelting current exists at the consumable electrode tip,resulting in thinner liquid melt film and smaller droplets.With the increase in magnetic flux density,the optimization effect of ASMFs on electroslag remelting process increases and reaches the peak with a 40 mT ASMF,then decreases.The cleanliness of the ingots was improved,and the count of inclusions larger than 5μm was reduced.The microstructure of the ingots processed with a 40 mT ASMF was significantly refined.The depth of the metallic molten pool was reduced from 45.2 to 17.5 mm with the application of 40 mT ASMF.The tensile strength,impact toughness,and Rockwell hardness of the ingots obtained under the 40 mT ASMF were significantly improved.The mechanisms of the spin-vibration occurring at the electrode tip end were interpreted in detail to elucidate the effect of ASMFs.

Bending behavior of as-cast and annealed ZrCuNiAl bulk metallic glass

Here ZrCuNiAl bulk metallic glass samples were annealed below its glass transition temperature. The bending behaviors and thermal properties of the as-cast and the annealed samples were studied. The increase of annealing time leads to the transition from ductile to more brittle behavior during bending tests. Meanwhile, prolonging the annealing causes a gradual decrease in the free volume content. Based on free volume theory, the change in the microstructure and mechanical properties induced by annealing treatment has been interpreted in detail.

Motion and removal behavior of inclusions in electrode tip during magnetically controlled electroslag remelting:X-ray microtomography characterization and modeling verification

Detailed three-dimensional(3 D)microtomography characterizations of inclusions in electrode matrix,mushy zone(MZ)and liquid melt film(LMF)were performed to elucidate the motion and removal behavior of inclusions in electrode tip during magnetically controlled electroslag remelting(MC-ESR)process.A transient 2 D numerical model was also built to verify the experimental results and proposed mechanisms.The number and size of inclusions exhibited an obvious increasing trend from edge to mid region in LMF,while remained almost the same in electrode matrix and MZ.The inclusions in LMF migrated from edge to mid region of LMF,accompanied with removal process.In addition,the kinetic conditions for inclusion migrating to LMF/slag interface(LSI)were enhanced during MC-ESR process,thereby improving the inclusion removal efficiency in LMF.This work highlights the 3 D characterization and motion/removal mechanisms of inclusions in electrode tip,as well as sheds new light on preparing high purity materials.

公司现金持有研究综述

现金是公司流动性管理中最重要的工具,因其灵活性和流动性成为公司投融资的关键因素。国内外关于现金持有的研究脉络大致可以分为现金持有的动态变化、现金持有的决定因素、现金持有的经济后果三个部分。经典的理论有权衡理论和代理理论两大类,前者侧重现金持有中的成本-收益分析,而后者则侧重于公司内部治理问题。本文汇总了国内外现金持有的相关研究,并结合中国特有的制度因素对未来研究提供了方向与建议。

Donut-like photonic nanojet with reverse energy flow

Photonic nanojets(PNJs)are subwavelength jet-like propagating waves generated by illuminating a dielectric microstructure with an electromagnetic wave,conventionally a linearly polarized plane wave.Here,we study the donut-like PNJ produced when a circularly polarized vortex beam is used instead.This novel PNJ also has a reverse energy flow at the donut-like focal plane depending on both the optical vortex topological charge and microsphere size.Our tunable PNJ,which we investigate numerically and analytically,can find applications in optical micromanipulation and trapping.

Enhanced electrical,mechanical and tribological properties of Cu-Cr-Zr alloys by continuous extrusion forming and subsequent aging treatment

As a promising material for the new generation of high-speed railway contact wires,the comprehensive optimization of the electrical conductivity,strength,hardness and wear resistance of the Cu-Cr-Zr alloy has received extensive attention.In this paper,a high-performance Cu-1Cr-0.1Zr alloy with an ultimate tensile strength of 599.1 MPa,a uniform elongation of 8.6%,a microhardness of 195.7 HV_(0.2) and an electrical conductivity of 80.07%IACS was achieved by the continuous extrusion forming(CEF)and subsequent peak-aging treatment.The grain refinement strengthening,dislocation strengthening and precipitation strengthening are identified to be responsible for the excellent electrical and mechanical properties of Cu-Cr-Zr alloy.The wear behavior of Cu-Cr-Zr alloy was investigated by examining the evolution of worn surface morphology and subsurface microstructure.The microhardness(H)and reduced elastic modulus(E_(r))of the subsurface below the worn surface measured by nanoindentation were calculated to gage the tribological performance of Cu-Cr-Zr alloy.Results show that the continuously extruded and subsequently peak-aged specimen has the best wear resistance,which indicates that the tribological properties of CuCr-Zr alloy strongly depend on its strength and hardness.It can be concluded that the CEF and subsequent aging treatment process provides a new and high-efficiency procedure for the continuous preparation of Cu-Cr-Zr alloys.