Rheological study of methane gas hydrates in the presence of micron-sized sand particles

Natural gas hydrates,intricate crystalline structures formed by water molecules and small gas molecules,have emerged as a significant and globally impactful clean energy resource.However,their commercial exploitation faces challenges,particularly operational disruptions caused by sand-related blockages.Understanding the rheological properties of hydrate slurry,especially in the presence of micron-sized sand particles,is imperative for ensuring the flow assurance of subsea hydrate exploitation.This study extensively investigates the rheological properties of sand-containing hydrate slurries.The findings reveal that these slurries exhibit non-Newtonian fluid characteristics,including yield stress,thixotropy,and shear-thinning behavior.Solid-like elastic features are observed in sand-containing hydrate slurries before yielding,transitioning to viscous behavior after yielding.Even with a minimal amount of sand,both static yield stress and yield strain experience substantial changes,correlating with the increase in sand concentration.The research conclusively establishes the thixotropic nature of sand-hydrate slurries,where the viscosity decay rate is directly influenced by the shear rate.These insights aim to contribute comprehensively to the development of effective flow assurance strategies,ensuring the safe and stable operation of subsea hydrate exploitation.

Magnetic and electrical transport properties in GdAlSi and SmAlGe

We conduct a detailed examination of the magnetic and electrical transport properties in GdAlSi and SmAlGe crystals,which possess a LaPtSi-type structure(space group I4_(1)md).The magnetic susceptibility data unambiguously reveal magnetic ordering below a characteristic transition temperature(T_(N)).For GdAlSi,a hysteresis loop is observed in the magnetization and magnetoresistance curves within the ab plane when the magnetic field is applied below T_(N),which is around32 K.Notable specific heat anomalies are detected at 32 K for GdAlSi and 6 K for SmAlGe,confirming the occurrence of magnetic transitions.In addition,the extracted magnetic entropy at high temperatures is consistent with the theoretical value of Rln(2J+1) for J=7/2 in Gd^(3+) and J=5/2 in Sm^(3+),respectively.SmAlGe also exhibits Schottky-like specific heat contributions.Additionally,both GdAlSi and SmAlGe exhibit positive magnetoresistance and a normal Hall effect.

Numerical simulation study on multiphase flow pattern of hydrate slurry

The research on the multiphase flow characteristics of hydrate slurry is the key to implementing the risk prevention and control technology of hydrate slurry in deep-water oil and gas mixed transportation system.This paper established a geometric model based on the high-pressure hydrate slurry experimental loop.The model was used to carry out simulation research on the flow characteristics of gas-liquid-solid three-phase flow.The specific research is as follows:Firstly,the effects of factors such as slurry flow velocity,hydrate particle density,hydrate particle size,and hydrate volume fraction on the stratified smooth flow were specifically studied.Orthogonal test obtained particle size has the most influence on the particle concentration distribution.The slurry flow velocity is gradually increased based on stratified smooth flow.Various flow patterns were observed and their characteristics were analyzed.Secondly,increasing the slurry velocity to 2 m/s could achieve the slurry flow pattern of partial hydrate in the pipeline transition from stratified smooth flow to wavy flow.When the flow rate increases to 3 m/s,a violent wave forms throughout the entire loop.Based on wave flow,as the velocity increased to 4 m/s,and the flow pattern changed to slug flow.When the particle concentration was below 10%,the increase of the concentration would aggravate the slug flow trend;if the particle concentration was above 10%,the increase of the concentration would weaken the slug flow trend,the increase of particle density and liquid viscosity would weaken the tendency of slug flow.The relationship between the pressure drop gradients of several different flow patterns is:slug flow>wave flow>stratified smooth flow.

Progress in Processes and Catalysts for Dehydrogenation of Cyclohexanol to Cyclohexanone

The dehydrogenation of cyclohexanol to cyclohexanone is a crucial industrial process in the production of caprolactam and adipic acid, both of which serve as important precursors in nylon textiles. This endothermic reaction is constrained by thermodynamic equilibrium and involves a complex reaction network, leading to a heightened focus on catalysts and process design. Copper-based catalysts have been extensively studied and exhibit exceptional low-temperature catalytic performance in cyclohexanol dehydrogenation, with some being commercially used in the industry. This paper specifically concentrates on research advancement concerning active species, reaction mechanisms, factors influencing product selectivity, and the deactivation behaviors of copper-based catalysts. Moreover, a brief introduction to the new processes that break thermodynamic equilibrium via reaction coupling and their corresponding catalysts is summarized here as well. These reviews may off er guidance and potential avenues for further investigations into catalysts and processes for cyclohexanol dehydrogenation.

帕博利珠单抗治疗后应用阿莫西林致斑丘疹1例

1例64岁男性右肺腺癌患者行化疗联合帕博利珠单抗治疗2周期后发生4级免疫介导肝损伤而住院治疗,期间服用阿莫西林胶囊0.5 g,q8h治疗肺部感染,用药约10 h后躯干部出现斑丘疹型药疹,未行处理。第2天早上皮疹遍布躯干部及双上肢,颜色加深。停用可疑药物阿莫西林胶囊,给予苯海拉明20 mg,im,盐酸西替利嗪10 mg,po,qd。第3天患者双上肢皮疹消失,躯干部皮疹部分消退,皮疹颜色变浅。第6天皮疹全部消失。患者既往多次服用阿莫西林,均未发生过敏反应,考虑本次出现阿莫西林致斑丘疹型药疹与帕博利珠单抗使用后引起的免疫状态过度激活有关。

胰腺分裂症的内镜诊治方法及临床价值

目的探讨胰腺分裂症(PD)内镜诊治的常规及补救方法、临床疗效和安全性。方法回顾性分析该院2014年1月-2016年12月经内镜下逆行胰胆管造影(ERCP)诊治的17例PD患者的临床病历资料,并电话回访患者症状改善及术后恢复情况。结果 17例PD患者,仅1例进行了再次内镜下治疗,共进行内镜下治疗18例次。内镜下治疗常规策略包括:副乳头括约肌切开术(MiES)、副胰管支架置入术(EDSi)及副乳头括约肌扩张术(MiED)。术中16例次手术过程顺利,2例次经过困难,但最终采用补救方法联合超声内镜(EUS)对接技术使手术成功。术后并发出血1例次,并发支架相关性胰腺炎2例次,无穿孔和发热等其他并发症发生。17例患者无1例失访,随访时间(16.3±9.4)个月,所有患者术后腹痛视觉模拟评分(VAS)较术前明显改善[(2.0±1.2)vs(7.0±1.8)分],差异有统计学意义(P <0.05)。结论内镜诊治PD具有安全、有效、创伤及并发症少等特点,可明显改善患者临床症状,值得临床推广。根据临床情况可选择常规方法诊治,对于插管困难患者,可联合EUS通过对接技术进行补救诊治。

腹直肌鞘联合腹横筋膜平面神经阻滞对脾切除患者术后恢复的影响

目的研究超声引导下腹直肌鞘联合腹横筋膜平面神经阻滞对脾切除患者术后疼痛缓解和恢复的影响。方法选取2018年3月—2018年7月于哈尔滨医科大学附属第二医院择期开腹脾切除术患者150例。患者随机分为对照组、左旋布比卡因组及左旋布比卡因联合吗啡组。所有患者进行超声引导下腹直肌鞘联合腹横筋膜平面神经阻滞,对照组注射生理盐水,左旋布比卡因组注射左旋布比卡因,左旋布比卡因联合吗啡组注射左旋布比卡因联合吗啡。记录术中阿片类药物的用量、手术持续时间、麻醉苏醒时间、术后疼痛评分、术后首次使用镇痛药的时间、吗啡的用量,以及术后首次排气、排便、进食及离床的时间,对患者术后恶心呕吐发生率和患者满意度进行调查。结果左旋布比卡因组和左旋布比卡因联合吗啡组瑞芬太尼使用量、术后苏醒时间较对照组少(P<0.05);左旋布比卡因联合吗啡组静息和咳嗽状态下VAS评分低于对照组(P<0.05),术后4~72 h,左旋布比卡因联合吗啡组静息VAS低于左旋布比卡因组(P<0.05),左旋布比卡因联合吗啡组咳嗽VAS低于左旋布比卡因组(P<0.05);对照组首次使用镇痛药的时间较左旋布比卡因组和左旋布比卡因联合吗啡组短(P<0.05);左旋布比卡因联合吗啡组吗啡总消耗量较对照组少(P<0.05),对照组较左旋布比卡因组少(P<0.05);左旋布比卡因组和左旋布比卡因联合吗啡组术后首次排气、排便和离床时间较对照组短(P<0.05);左旋布比卡因联合吗啡组首次进食时间、止吐药用量较对照组少(P<0.05);左旋布比卡因联合吗啡组满意度评分较左旋布比卡因组和对照组高(P<0.05)。结论使用左旋布比卡因联合吗啡进行腹直肌鞘联合腹横筋膜平面神经阻滞可以缓解术后疼痛,减少术后镇痛药的使用,并促进患者康复。

New role for ceramide in hypoxia and insulin resistance

Ceramides are significant metabolic products of sphingolipids in lipid metabolism and are associated with insulin resistance and hepatic steatosis. In chronic inflammatory pathological conditions, hypoxia occurs, the metabolism of ceramide changes, and insulin resistance arises. Hypoxia-inducible factors(HIFs)are a family of transcription factors activated by hypoxia. In hypoxic adipocytes,HIF-1α upregulates pla2 g16(a novel HIF-1α target gene) gene expression to activate the NLRP3 inflammasome pathway and stimulate insulin resistance, and adipocyte-specific Hif1 a knockout can ameliorate homocysteine-induced insulin resistance in mice. The study on the HIF-2α-NEU3-ceramide pathway also reveals the role of ceramide in hypoxia and insulin resistance in obese mice.Under obesity-induced intestinal hypoxia, HIF-2α increases the production of ceramide by promoting the expression of the gene Neu3 encoding sialidase 3,which is a key enzyme in ceramide synthesis, resulting in insulin resistance in high-fat diet-induced obese mice. Moreover, genetic and pathophysiologic inhibition of the HIF-2α-NEU3-ceramide pathway can alleviate insulin resistance, suggesting that these could be potential drug targets for the treatment of metabolic diseases. Herein, the effects of hypoxia and ceramide, especially in the intestine, on metabolic diseases are summarized.

Natural gas hydrate shell model in gas-slurry pipeline flow

A hydrate shell model coupled with one-dimensional two-fluid pipe flow model was established to study the flow characteristics of gas-hydrate slurry flow system.The hydrate shell model was developed with kinetic limitations and mass transfer limitations,and it was solved by Euler method.The analysis of influence factors was performed.It was found that the diffusion coefficient was a key parameter in hydrate forming process.Considering the hydrate kinetics model and the contacting area between gas and water,the hydrate shell model was more close to its practical situations.

Clinical characteristics and risk factors for liver injury in COVID-19 patients in Wuhan

BACKGROUND Coronavirus disease 2019(COVID-19)has become a worldwide pandemic.We investigated the clinical characteristics and risk factors for liver injury in COVID-19 patients in Wuhan by retrospectively analyzing the epidemiological,clinical,and laboratory data for 218 COVID-19 patients and identifying the risk factors for liver injury by multivariate analysis.AIM To investigate the clinical characteristics and risk factors for liver injury in COVID-19 patients in Wuhan.METHODS The 218 patients included 94 males(43.1%),aged 22 to 94(50.1±18.4)years.Elevated aspartate aminotransferase(AST)and alanine aminotransferase(ALT)were present in 42(53.2%)and 36(45.6%)cases,respectively,and 79(36.2%)patients had abnormally elevated transaminase levels at admission.Patients with liver injury were older than those with normal liver function by a median of 12 years,with a significantly higher frequency of males(68.4%vs 28.8%,P<0.001)and more coexisting illnesses(48.1%vs 27.3%,P=0.002).Significantly more patients had fever and shortness of breath(87.3%vs 69.8%and 29.1%vs 14.4%,respectively)in the liver injury group.Only 12(15.2%)patients had elevated total bilirubin.ALT and AST levels were mildly elevated[1-3×upper limit of normal(ULN)]in 86.1%and 92.9%of cases,respectively.Only two(2.5%)patients had an ALT or AST level>5×ULN.Elevatedγ-glutamyl transpeptidase was present in 45(57.0%)patients,and 86.7%of these had aγ-glutamyl-transpeptidase level<135 U/L(3×ULN).Serum alkaline phosphatase levels were almost normal in all patients.Patients with severe liver injury had a significantly higher frequency of abnormal transaminases than non-severe patients,but only one case had very high levels of aminotransferases.RESULTS Multivariate analysis revealed that male sex,high D-dimer level,and high neutrophil percentage were linked to a higher risk of liver injury.The early stage of COVID-19 may be associated with mildly elevated aminotransferase levels in patients in Wuhan.Male sex and high D-dimer level and neutrophil percentage may be important predictors of liver injury in patients with COVID-19.CONCLUSION Male sex and high D-dimer level and neutrophil percentage may be important predictors of liver injury in patients with COVID-19.

Synergistic effect of magnetic field and nanocomposite pour point depressant on the yield stress of waxy model oil

Yield stress,as the key parameter to characterize the network strength of waxy oil,is important to the petroleum pipeline safety.Reducing the yield stress of waxy oil is of great significance for flow assurance.In this study,the effect of alternating magnetic field(intensity,frequency)on the yield stress of a waxy model oil with nanocomposite pour point depressant(NPPD)is systematically investigated.An optimum magnetic field intensity and frequency is found for the reduction in yield stress.When adding with NPPD,the heterogeneous nucleation of NPPD contributes to the reduction in yield stress for waxy model oil.Interestingly,the magnetic field is helpful for the modification of yield stress at a lower frequency and intensity before the optimal value;however,the modification is found to be weakened when the magnetic field is further increased after the optimal value.Possible explanation is proposed that the aggregation morphology of wax crystal would be altered and results in the release of wrapped oil phase from the network structure under the magnetic field.

Investigations on methane hydrate formation,dissociation,and viscosity in gas-water-sand system

Understanding the kinetics and viscosity of hydrate slurry in gas-water-sand system is of great significance for the high-efficiency and high-safety development of natural gas hydrates.The effect of micronsized sands with various concentrations and particle sizes on the hydrate formation,dissociation,and viscosity in gas-water-sand system are investigated in this work.The experimental results show that the hydrate induction time in the sandy system is slightly prolonged compared to the pure gas-water system,and the inhibition effect first strengthens and then weakens as the sand concentration increases from0 wt%to 5 wt%.Besides,the difference of hydrate formation amount in various cases is not obvious.The concentration and particle size of sand have little effect on the kinetics of hydrate formation.Both promoting and inhibiting effects on hydrate formation have been found in the sandy multiphase fluid.For the viscosity characteristics,there are three variations of hydrate slurry viscosity during the formation process:Steep drop type,S-type and Fluctuation type.Moreover,appropriate sand size is helpful to reduce the randomness of slurry viscosity change.Meanwhile,even at the same hydrate volume fraction,the slurry viscosity in the formation process is significantly higher than that in dissociation process,which needs further research.This work provides further insights of hydrate formation,dissociation,and viscosity in gas-water-sand system,which is of great significance for safe and economic development of natural gas hydrates.

A liquid loading prediction method of gas pipeline based on machine learning

The liquid loading is one of the most frequently encountered phenomena in the transportation of gas pipeline,reducing the transmission efficiency and threatening the flow assurance.However,most of the traditional mechanism models are semi-empirical models,and have to be resolved under different working conditions with complex calculation process.The development of big data technology and artificial intelligence provides the possibility to establish data-driven models.This paper aims to establish a liquid loading prediction model for natural gas pipeline with high generalization ability based on machine learning.First,according to the characteristics of actual gas pipeline,a variety of reasonable combinations of working conditions such as different gas velocity,pipe diameters,water contents and outlet pressures were set,and multiple undulating pipeline topography with different elevation differences was established.Then a large number of simulations were performed by simulator OLGA to obtain the data required for machine learning.After data preprocessing,six supervised learning algorithms,including support vector machine(SVM),decision tree(DT),random forest(RF),artificial neural network(ANN),plain Bayesian classification(NBC),and K nearest neighbor algorithm(KNN),were compared to evaluate the performance of liquid loading prediction.Finally,the RF and KNN with better performance were selected for parameter tuning and then used to the actual pipeline for liquid loading location prediction.Compared with OLGA simulation,the established data-driven model not only improves calculation efficiency and reduces workload,but also can provide technical support for gas pipeline flow assurance.

Experimental investigation of erosion rate for gas-solid two-phase flow in 304 stainless/L245 carbon steel

Erosion is one of the most concerning issues in pipeline flow assurance for the Oil&Gas pipeline industries,which can easily lead to wall thinning,perforation leakage,and other crucial safety risks to the steady operation of pipelines.In this research,a novel experimental device is designed to investigate the erosion characteristics of 304 stainless and L245 carbon steel in the gas-solid two-phase flow.Regarding the impacts on erosion rate,the typical factors such as gas velocity,impact angle,erosion time,particle material and target material are individually observed and comprehensive analyzed with the assistance of apparent morphology characterized via Scanning Electron Microscope.Experimental results show that the severest erosion occurs when the angle reaches approximate 30°whether eroded by type I or type II particles,which is observed in both two types of steel.Concretely,304 stainless steel and L245 carbon steel appear to be cut at low angles,and impacted at high angles to form erosion pits.In the steady operational state,the erosion rate is insensitive to the short erosion time and free from the influences caused by the“erosion latent period”.Based on the comparison between experimental data and numerical results generated by existing erosion models,a modified model with low tolerance(<3%),high feasibility and strong consistency is proposed to make an accurate prediction of the erosion in terms of two types of steel under various industrial conditions.

Short-term outcomes of laparoscopic total mesorectal excision compared to open surgery

AIM:To investigate the short-term outcome of laparoscopic total mesorectal excision(TME) in patients with mid and low rectal cancers.METHODS:A consecutive series of 138 patients with middle and low rectal cancer were randomly assigned to either the laparoscopic TME(LTME) group or the open TME(OTME) group between September 2008 and July 2011 at the Department of Colorectal Cancer of Shanghai Cancer Center,Fudan University and pathological data,as well as surgical technique were reviewed retrospectively.Short-term clinical and oncological outcome were compared in these two groups.Patients were followed in the outpatient clinic 2 wk after the surgery and then every 3 mo in the first year if no adjuvant chemoradiation was indicated.Statistical analysis was performed using SPSS 13.0 software.RESULTS:Sixty-seven patients were treated with LTME and 71 patients were treated with OTME(sex ratio 1.3:1vs 1.29:1,age 58.4 ± 13.6 years vs 59.6 ± 9.4 years,respectively).The resection was considered curative in all cases.The sphincter-preserving rate was 65.7%(44/67) vs 60.6%(43/71),P = 0.046;mean blood loss was 86.9 ± 37.6 mL vs 119.1 ± 32.7 mL,P = 0.018;postoperative analgesia was 2.1 ± 0.6 d vs 3.9 ± 1.8 d,P = 0.008;duration of urinary drainage was 4.7 ± 1.8 d vs 6.9 ± 3.4 d,P = 0.016,respectively.The conversion rate was 2.99%.The complication rate,circumferential margin involvement,distal margins and lymph node yield were similar for both procedures.No port site recurrence,anastomotic recurrence or mortality was observed during a median follow-up period of 21 mo(range:9-56 mo).CONCLUSION:Laparoscopic TME is safe and feasible,with an oncological adequacy comparable to the open approach.Further studies with more patients and longer follow-up are needed to confirm the present results.

Proteomics identifies a novel role of fibrinogen-like protein 1 in Crohn’s disease

BACKGROUND Crohn’s disease(CD)is an incurable intestinal disorder with unclear etiology and pathogenesis.Currently,there is a lack of specific biomarkers and drug targets for CD in clinical practice.It is essential to identify the precise pathophysiological mechanism of CD and investigate new therapeutic targets.AIM To explore a new biomarker and therapeutic target for CD and verify its role in the CD pathological mechanism.METHODS Proteomics was performed to quantify the protein profile in the plasma of 20 CD patients and 20 matched healthy controls.Hub genes among the selected differentially expressed proteins(DEPs)were detected via the MCODE plugin in Cytoscape software.The expression level of one hub gene with an immunoregulatory role that interested us was verified in the inflamed intestinal tissues of 20 CD patients by immunohistochemical analysis.After that,the effects of the selected hub gene on the intestinal inflammation of CD were identified in a CD cell model by examining the levels of proinflammatory cytokines by enzymelinked immunosorbent assays and the expression of the NF-κB signalling pathway by quantitative real-time PCR analysis and Western blot assays.RESULTS Thirty-five DEPs were selected from 393 credible proteins identified by proteomic analysis.Among the DEPs,fibrinogen-like protein 1(FGL1),which attracted our attention due to its function in the regulation of the immune response,had 1.722-fold higher expression in the plasma of CD patients and was identified as a hub gene by MCODE.Furthermore,the expression of FGL1 in the intestinal mucosal and epithelial tissues of CD patients was also upregulated(P<0.05).In vitro,the mRNA levels of FGL1 and NF-κB;the protein expression levels of FGL1,IKKα,IKKβ,p-IKKα/β,p-IκBα,and p-p65;and the concentrations of the proinflammatory cytokines IL-1β,IL-6,IL-17,and TNF-αwere increased(P<0.05)after stimulation with lipopolysaccharide,which were reversed by knockdown of FGL1 with siRNA transfection(P<0.05).Conversely,FGL1 overexpression enhanced the abovementioned results(P<0.05).CONCLUSION FGL1 can induce intestinal inflammation by activating the canonical NF-κB signalling pathway,and it may be considered a potential biomarker and therapeutic target for CD.

Fenugreek lactone attenuates palmitate-induced apoptosis and dysfunction in pancreatic β-cells

AIM: To investigate the effect of fenugreek lactone(FL) on palmitate(PA)-induced apoptosis and dysfunction in insulin secretion in pancreatic NIT-1 β-cells. METHODS: Cells were cultured in the presence or absence of FL and PA(0.25 mmol/L) for 48 h. Then, lipid droplets in NIT-1 cells were observed by oil red O staining, and the intracellular triglyceride content was measured by colorimetric assay. The insulin content in the supernatant was determined using an insulin radioimmunoassay. Oxidative stress-associated parameters, including total superoxide dismutase, glutathione peroxidase and catalase activity and malondialdehyde levels in the suspensions were also examined. The expression of upstream regulators of oxidative stress, such as protein kinase C-α(PKC-α), phospho-PKC-α and P47 phox, were determined by Western blot analysis and real-time PCR. In addition, apoptosis was evaluated in NIT-1 cells by flow cytometry assays and caspase-3 viability assays.RESULTS: Our results indicated that compared to the control group, PA induced an increase in lipid accumulation and apoptosis and a decrease in insulin secretion in NIT-1 cells. Oxidative stress in NIT-1 cells was activated after 48 h of exposure to PA. However, FL reversed the above changes. These effects were accompanied by the inhibition of PKC-α, phosphoPKC-α and P47 phox expression and the activation of caspase-3. CONCLUSION: FL attenuates PA-induced apoptosis and insulin secretion dysfunction in NIT-1 pancreatic β-cells. The mechanism for this action may be associated with improvements in levels of oxidative stress.

Impact of simethicone on bowel cleansing during colonoscopy in Chinese patients

BACKGROUND Four-liter polyethylene glycol(PEG)solutions are effective for bowel cleansing,but their large volume might hinder patient compliance.Due to the unique features of Asians,4 L PEG might be a suboptimal bowel preparation in predominantly ethnically Asian countries.In view of this,a balance should be achieved between the volume and effectiveness.The ideal bowel cleansing regimen for a colonoscopy has yet to be determined in a Chinese population.AIM To compare the cleansing efficacy of 3 L PEG plus simethicone with 4 L PEG.METHODS A total of 291 patients were randomly allocated to two groups:Group 1(n=145)received 4 L split-dose PEG(4-P);group 2(n=146)received 3 L split-dose PEG plus simethicone(3-PS).Bowel-cleansing efficacy was evaluated by endoscopists using the Boston bowel preparation scale(BBPS)and the bubbles score.RESULTS Although there were no significant differences in the total BBPS score or the adequate rate of bowel preparation between the two groups,the BBPS score of the right-side colon was significantly higher in the 3-SP group(2.37±0.54 vs 2.21±0.78;P=0.04).Moreover,the use of simethicone significantly reduced bubbles in all colon segments(P<0.001).The mean withdrawal time was significantly shorter in the 3-PS group(8.8±3.4 vs 9.6±2.3;P=0.02).Furthermore,significantly more proximal adenomas were detected in the 3-PS group(53.6%vs 45.7%;P=0.03).In addition,the proportions of patients with nausea and bloating were significantly lower in the 3-SP group(P<0.01 for both).More patients in the 3-PS group expressed willingness to repeat the bowel preparation(87.7%vs 76.6%,P=0.01).CONCLUSION Three-liter PEG shows satisfactory bowel cleansing despite the decrease in dosage,and addition of simethicone with better bubble elimination and enhanced patient acceptance offers excellent potential impact on the detection of proximal adenomas in Chinese patients.

Probing surface interactions of underwater oleophobic polyelectrolyte multilayers

In the present work,the interaction mechanism of specific polyelectrolyte multilayers(PEMs),fabricated by layer-by-layer deposition of polydiallyldimethylammonium chloride(PDDA)and poly(sodium 4-styrenesulfonate)(PSS),is studied using atomic force microscopy.The underwater oil-repellency of PS S-capped PEMs was further explored by measuring the interaction forces between tetradecane droplets and PEMs-coated silica substrates under various salinities.The force curves were analyzed following the Stokes-Reynolds-Young-Laplace theoretical model.Desirable consistency was achieved between the experimental and theoretical calculations at low NaCl concentrations(0.1 mM and 1 mM);however,underestimation of the attractive force was found as the NaCl concentration increases to moderate(10 mM)and high(100 mM)levels.Discrepancy analyses and incorporated features toward a reduced surface charge density were considered based on the previous findings of the orientation of anionic benzenesulfonate moieties(Liu et al.in Angew Chem Int Ed 54(16):4851-4856,2015.https://doi.org/10.1002/anie.201411992).Short-range steric hindrance interactions were further introduced to simulate"brush"effect stemming from nanoscale surface roughness.It is demonstrated in our work that the PSS-capped PEMs remains a stable underwater lipophobicity against high salinity,which renders it potential application in surface wetting modification and anti-fouling.

Effect of antifoaming agent on benign colorectal tumors in colonoscopy:A meta-analysis

BACKGROUND Although several trials have shown that the addition of antifoaming agents to polyethylene glycol(PEG)can improve bowel preparation,whether PEG plus antifoaming agents have a beneficial role in the detection of benign tumors during colonoscopy has yet to be confirmed.Our aim was to clarify whether adding simethicone to PEG solution could improve the detection of benign colorectal tumors.AIM To clarify whether adding simethicone to PEG solution could improve the detection of benign colorectal tumors.METHODS The PubMed,EMBASE,and Cochrane Library databases were searched for articles published prior to September 2019.The outcomes included the detection rates of colorectal adenomas and polyps.RESULT Twenty studies were eligible.Although there was no difference in the colorectal adenoma detection rate(ADR),a significant effect of simethicone for diminutive adenomas(<10 mm)was revealed in the group taking simethicone.We also found that simethicone could significantly improve the ADR in the proximal colon but did not affect the colorectal polyp detection rate.Furthermore,the subgroup analyses revealed a beneficial effect of simethicone on the ADR among Asians(P=0.005)and those with an ADR<25%(P=0.003).Moreover,it was a significant finding that the low dose simethicone was as effective as the high dose one with respect to the detection of benign colorectal tumors.CONCLUSION In summary,the addition of simethicone to PEG might improve the detection of diminutive adenomas in the right colon by colonoscopy in Asia.Low-dose simethicone was recommended for the detection of benign colorectal tumors.However,large clinical trials are necessary to validate our results and determine the ideal dose of simethicone.