Temperature dependence of mechanical properties and damage evolution of hot dry rocks under rapid cooling

Understanding the differences in mechanical properties and damage characteristics of granitoid under high temperatures is crucial for exploring deep geothermal resources.This study analyzes the evolution of the acoustic emission(AE)characteristics and mechanical parameters of granodiorite and granite after heating and water cooling by uniaxial compression and variable-angle shear tests under different temperature gradients.We identify their changes in mesostructure and mineral composition with electron probe microanalysis and scanning electron microscopy.Results show that these two hot dry rocks have similar diagenetic minerals and microstructure,but show significantly different mechanical and acoustic characteristics,and even opposing evolution trends in a certain temperature range.At the temperatures ranging from 100℃to 500℃,the compressive and shear mechanical properties of granodiorite switch repeatedly between weakening and strengthening,and those of granite show a continuous weakening trend.At 600℃,both rocks exhibit a deterioration of mechanical properties.The damage mode of granite is characterized by initiating at low stress,exponential evolutionary activity,and intensified energy release.In contrast,granodiorite exhibits the characteristics of initiating at high stress,volatile evolutionary activity,and intermittent energy release,due to its more stable microstructure and fewer thermal defects compared to granite.As the temperature increases,the initiation and propagation of secondary cracks in granodiorite are suppressed to a certain extent,and the seismicity and brittleness are enhanced.The subtle differences in grain size,microscopic heterogeneity,and mineral composition of the two hot dry rocks determine the different acoustic-mechanical characteristics under heating and cooling,and the evolution trends with temperature.These findings are of great significance for the scientific and efficient construction of rock mass engineering by rationally utilizing different rock strata properties.

Silent information regulator sirtuin 1 ameliorates acute liver failure via the p53/glutathione peroxidase 4/gasdermin D axis

BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rate,and GSDMD expression,restoring SLC7A11 depletion.Moreover,SIRT1 agonist and overexpression of SIRT1 alleviated acute liver injury and decreased iron deposition compared with results in the model group,accompanied by reduced p53,GSDMD,and ACSL4,and increased SLC7A11 and GPX4.Inactivation of SIRT1 exacerbated ferroptotic and pyroptotic cell death and aggravated liver injury in LPS/D-GalNinduced in vitro and in vivo models.CONCLUSION SIRT1 activation attenuates LPS/D-GalN-induced ferroptosis and pyroptosis by inhibiting the p53/GPX4/GSDMD signaling pathway in ALF.

Occult pancreaticobiliary reflux is a pathogenic factor of some benign biliary diseases and gallbladder cancer

Background:Pancreaticobiliary maljunction(PBM)is a well-known high-risk factor for biliary malignant tumors because of constant pancreaticobiliary reflux(PBR).However,the impact of occult pancreaticobiliary reflux(OPR),which is characterized by high bile amylase levels in individuals with anatomically normal pancreaticobiliary junction,on biliary diseases remains unclear.The aim of this study was to assess the correlation between OPR and biliary diseases.Methods:We enrolled 94 consecutive patients with normal pancreaticobiliary junction and primary biliary diseases confirmed by magnetic resonance cholangiopancreatography.We prospectively collected patients’bile samples and measured bile amylase levels.We investigated the incidence of OPR and the difference in bile amylase levels among these patients and assessed the correlation between high bile amylase levels(HBAL)and benign or malignant biliary diseases,as well as the OPR risk factors.Results:The incidence of OPR was 36.6%in patients with benign biliary diseases,26.7%in those with cholangiocarcinoma and 62.5%in those with gallbladder cancer.The median bile amylase level tended to be higher in patients with gallbladder cancer than in those with benign biliary diseases,but there was no significant difference(165.5 IU/L vs.23.0 IU/L,P=0.212).The prevalence of an HBAL with bile amylase levels of 1000-7500 IU/L was similar in patients with gallbladder cancer and benign biliary diseases.However,the incidence of HBAL with bile amylase levels greater than 7500 IU/L was significantly higher in patients with gallbladder cancer than in those with benign biliary diseases(37.5%vs.4.2%,P=0.012).Multivariate logistic regression analysis revealed that choledocholithiasis was an independent risk factor for OPR.Conclusions:OPR can occur in benign and malignant biliary diseases,and it may be a pathogenic factor for some benign biliary diseases and a high-risk factor for gallbladder cancer.There is a correlation between choledocholithiasis and OPR.

Latest developments in EUV photoresist evaluation capability at Shanghai Synchrotron Radiation Facility

Evaluating the comprehensive characteristics of extreme ultraviolet(EUV)photoresists is crucial for their application in EUV lithography,a key process in modern technology.This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility(SSRF)08U1B beamline in advancing this field.Specifically,it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch on a resist using synchrotron-based EUV lithography.This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node.We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist.A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane mask gratings.These gratings,with an aspect ratio of approximately 3,were created using electron beam lithography on an innovative mask framework.This framework was crucial in eliminating the impact of zeroth-order light on interference patterns.The proposed framework propose offers a new approach to mask fabrication,particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.

Value and prognostic factors of repeat hepatectomy for recurrent colorectal liver metastasis

Background:More than 50%of patients with colorectal cancer develop liver metastases.Hepatectomy is the preferred treatment for resectable liver metastases.This review provides a perspective on the utility and relevant prognostic factors of repeat hepatectomy in recurrent colorectal liver metastasis(CRLM).Data sources:The keywords“recurrent colorectal liver metastases”,“recurrent hepatic metastases from colorectal cancer”,“liver metastases of colorectal cancer”,“repeat hepatectomy”,“repeat hepatic resec-tion”,“second hepatic resection”,and“prognostic factors”were used to retrieve articles published in the PubMed database up to August 2020.Additional articles were identified by a manual search of references from key articles.Results:Despite improvements in surgical methods and perioperative chemotherapy,recurrence remains common in 37%-68%of patients.Standards or guidelines for the treatment of recurrent liver metastases are lacking.Repeat hepatectomy appears to be the best option for patients with resectable metastases.The commonly reported prognostic factors after repeat hepatectomy were R0 resection,carcinoembryonic antigen level,the presence of extrahepatic disease,a short disease-free interval between initial and repeat hepatectomy,the number(>1)and size(≥5 cm)of hepatic lesions,requiring blood transfusion,and no adjuvant chemotherapy after initial hepatectomy.The median overall survival after repeat hepatectomy ranged from 19.3 to 62 months,and the 5-year overall survival ranged from 21%to 73%.Chemotherapy can act as a test for the biological behavior of tumors with the goal of avoiding unnecessary surgery,and a multimodal approach involving aggressive chemotherapy and repeat hepatectomy might be the treatment of choice for patients with early recurrent CRLM.Conclusions:Repeat hepatectomy is a relatively safe and effective treatment for resectable recurrent CRLM.The presence or absence of prognostic factors might facilitate patient selection to improve short-and long-term outcomes.

Breath-by-breath measurement of exhaled ammonia by acetonemodifier positive photoionization ion mobility spectrometry via online dilution and purging sampling

Exhaled ammonia(NH_(3))is an essential noninvasive biomarker for disease diagnosis.In this study,an acetone-modifier positive photoionization ion mobility spectrometry(AM-PIMS)method was developed for accurate qualitative and quantitative analysis of exhaled NH_(3)with high selectivity and sensitivity.Acetone was introduced into the drift tube along with the drift gas as a modifier,and the characteristic NH_(3)product ion peak of(C_(3)H_(6)O)_(4)NH_(4)^(+)(K_(0)=1.45 cm^(2)/V·s)was obtained through the ion-molecule reaction with acetone reactant ions(C_(3)H_(6)O)_(2)H^(+)(K_(0)=1.87 cm^(2)/V·s),which significantly increased the peak-to-peak resolution and improved the accuracy of exhaled NH_(3)qualitative identification.Moreover,the interference of high humidity and the memory effect of NH_(3)molecules were significantly reduced via online dilution and purging sampling,thus realizing breath-by-breath measurement.As a result,a wide quantitative range of 5.87-140.92μmol/L with a response time of 40 ms was achieved,and the exhaled NH_(3)profile could be synchronized with the concentration curve of exhaled CO_(2).Finally,the analytical capacity of AM-PIMS was demonstrated by measuring the exhaled NH_(3)of healthy subjects,demonstrating its great potential for clinical disease diagnosis.

Practical evaluation of prelithiation strategies for next-generation lithium-ion batteries

With the increasing market demand for high-performance lithium-ion batteries with high-capacity electrode materials,reducing the irreversible capacity loss in the initial cycle and compensating for the active lithium loss during the cycling process are critical challenges.In recent years,various prelithiation strategies have been developed to overcome these issues.Since these approaches are carried out under a wide range of conditions,it is essential to evaluate their suitability for large-scale commercial applications.In this review,these strategies are categorized based on different battery assembling stages that they are implemented in,including active material synthesis,the slurry mixing process,electrode pretreatment,and battery fabrication.Furthermore,their advantages and disadvantages in commercial production are discussed from the perspective of thermodynamics and kinetics.This review aims to provide guidance for the future development of prelithiation strategies toward commercialization,which will potentially promote the practical application of next-generation high-energy-density lithium-ion batteries.

Experimental and Numerical Study on Progressive Collapse Analysis of a Glulam Frame Structure:I.Side Column Exposed to Fire

This paper presents experimental and numerical investigations on progressive collapse behavior of a two-story glulam frame when the side column is exposed to ISO834 standard fire.The collapse mechanism initiated by fire is identified.The experimental results show that the progressive collapse of a glulam frame could be described for three stages,namely bending effect stage,catenary effect stage and failure stage,respectively.These stages are discussed in detail to understand the structural behavior before and during collapse.It is demonstrated that the entire frame slopes towards the side of the heated column,and the“overturning”collapse occurs eventually.The catenary effect of beams is the main reason for the progressive collapse of the frame.In addition,a finite element model of a glulam frame is established to simulate the progressive collapse behavior.The effects of axial loads on the columns are summarized.The numerical simulation results agree well with the experimental results,which could verify the effectiveness and practicability of finite element simulation.Furthermore,the progressive collapse resistance of the frame in practical design were proposed.

Outcomes and risk factors for failure of trabeculectomy in glaucomatous patients in Southwest China:a 325 eyes analysis

AIM:To evaluate the outcomes and elucidate the failure factors for trabeculectomy with mitomycin C(MMC)in Southwest Chinese patients.METHODS:A retrospective correlational study was conducted on the glaucomatous patients who underwent initial trabeculectomy with MMC in Southwest Hospital and had been followed up for 1-3y.A complete success for surgery is defined as a postoperative intraocular pressure(IOP)>5 and≤21 mm Hg and 20%reduction of IOP compared to preoperative,without IOP-lowering medications.A qualified success for surgery is defined as the abovementioned postoperative IOP with or without IOP-lowering medications.The primary outcomes were IOP,the number of IOP-lowering medications,and cumulative success rate.The secondary outcomes included best corrected visual acuity(BCVA),mean deviation(MD)of visual field,major complications,and risk factors for surgical failure.RESULTS:A total of 325 eyes of 261 glaucomatous patients had been included in our study.Both the mean IOP and the number of IOP-lowering medications were significantly decreased from 32.9±12.0 to 16.4±5.7 mm Hg(P<0.0001)and 3.0±0.9 to 0.9±1.0(P<0.0001),respectively,at the last visit.The cumulative complete success rate and qualified success rate were 77.8%and 92.0%at 1-year follow-up,and 47.2%and 77.7%at 3-year follow up.There were no significant differences in surgical outcomes between primary angle-closure glaucoma(PACG)and primary open angle glaucoma(POAG).In PACG patients,the success rates of trabeculectomy were comparable with those of phacotrabeculectomy.Hypertension(HR=1.904,P=0.011),encapsulated bleb(HR=2.756,P<0.001),and more preoperative topical medications(HR=2.475,P=0.008)were risk factors for surgical failure.CONCLUSION:The qualified success rate of trabeculectomy with MMC in glaucomatous patients in the cohort is 92.0%at 1-year,and 77.7%at 3-year follow up.Hypertension,encapsulated bleb,and more preoperative topical medications are associated with surgical failure.

A Review of the Application of Process Evaluation in Junior High School English Teaching under “Double Reduction”

The “Double Reduction” policy is not only to reduce the excessive learning burden of students, but also to improve the quality of students’ learning and to promote their overall development. In order to achieve the goal of the “Double Reduction” policy, it is necessary to focus on the implementation of measures to strengthen process evaluation as proposed in the “General Plan for Deepening Education Evaluation Reform in a New Era”. Therefore, the article will analyze the current situation of the research from three aspects: the connotation of “Double Reduction” and process evaluation, process evaluation under “Double Reduction” and process evaluation in English teaching, and look forward to the future development trend, with the aim of implementing the “Double Reduction” policy and giving full play to process evaluation. The aim is to implement the policy of “Double Reduction” and give full play to the role of process evaluation, so as to effectively guide the practice of English teaching.

花岗岩在不同温度劈裂载荷下的损伤演化与失稳前兆

为了阐明深地钻探中花岗岩在劈裂载荷与高温作用下的复杂机械和损伤特性,对经50~600℃处理的花岗岩试样进行巴西劈裂声发射(AE)试验。结果表明,温度变化会使花岗岩的机械与声发射特性发生改变,从而改变其破裂演化过程。当温度超过500℃时,花岗岩的抗拉强度大幅降低,剪切损伤模式占比增加。此外,破裂速率亦呈现明显增长趋势。在基于撞击数和能量计数的损伤参数演化曲线的基础上,定义“损伤参数突变点”来判断作为岩石破坏的前兆信息。基于撞击数的“突变点”比岩石失稳的信号提前到达,且岩石损伤越大,提前的时间越久。通过这个时间差,可以达到预警岩石失稳的效果。

有机-有机界面效应的原位及非原位研究

有机-有机异质结构已被广泛应用于各种有机电子器件,包括有机发光二极管(OLEDs)、有机场效应晶体管(OFETs)和有机太阳能电池等。全面理解有机-有机异质结构的界面效应,对于器件的设计和性能优化具有重要意义。然而由于有机半导体具有多样的化学特性以及分子间较弱的范德华力,界面电荷传输特性与有机-有机电子结构、环境气氛等密切相关。在此,我们报道了随着顶层半导体并五苯(pentacene)的沉积,并五苯/酞菁氧钒(VOPc)异质结构的原位实时电学性能监测。结果显示,异质结构晶体管的p型迁移率从0.4 cm2∙V−1∙s^(−1)下降至0.2 cm2∙V−1∙s^(−1),而n型迁移率从0.01 cm2∙V−1∙s^(−1)迅速增加至约0.9 cm2∙V−1∙s^(−1)。这种n型输运行为的增强归因于pentacene向VOPc的界面电子转移效应以及由此导致的VOPc层中陷阱态的填充。此外,非原位实验对比表明,当晶体管制备过程暴露于大气时会明显抑制这种界面电荷转移效应,导致沉积pentacene后n型输运几乎没有得到改善。薄膜形态、开尔文探针力显微镜(KPFM)和X射线光电子能谱(XPS)的结果表明,界面处存在从pentacene到VOPc的电子转移。进一步的密度泛函理论(DFT)计算表明,由于pentacene/VOPc之间较强的相互作用,pentacene往VOPc的电荷转移量约为0.15 e。此外,O_(2)/H2O的存在会抑制这种界面电荷转移效应,这与我们的实验结果一致。本研究通过原位电学表征对有机-有机界面之间的电荷转移效应给出了深入解释,有利于进一步的器件性能优化及界面效应分析。

针刺联合耳穴压籽治疗后循环缺血性眩晕疗效观察

目的使用经颅多普勒超声(transcranial doppler,TCD)、眩晕障碍量表(dizziness handicap inventory,DHI)、眩晕评估评分量表(dizziness assessment rating scale,DARS)及中医证候量表评价针刺联合耳穴压籽治疗后循环缺血性眩晕的疗效。方法招募上海中医药大学附属龙华医院后循环缺血性眩晕(气血亏虚型)患者67例,随机分为治疗组(针刺+耳穴压籽治疗)34例和对照组(针刺治疗)33例。针刺选穴为百会、风池、肾俞、肝俞、脾俞、足三里。针刺治疗每次20 min,1周3次,12次(4周)为1个疗程。耳穴压籽选穴:枕、皮质下、神门、脾,于每日早晨7:00至晚间7:00嘱患者对穴位进行4次按压,每3 h 1次,每个穴位匀速按压30次。治疗次数:两耳交替压籽,1周3次,12次(4周)为1个疗程。在治疗前、治疗2周、治疗4周时分别对患者进行TCD检测以及DHI、DARS、中医证候积分评分。结果治疗组在治疗2周和4周后对后循环缺血性眩晕(posterior circulation ischemic vertigo,PCIV)患者的DHI和中医证候积分改善较对照组明显(P<0.05),对DARS积分的改善较对照组差异无统计学意义(P>0.05);两组分别在治疗2周后和治疗4周后对DHI、DARS以及中医证候积分改善较治疗前明显(P<0.05),并且治疗4周后较治疗2周后改善也明显(P<0.05);治疗组和对照组治疗2周后基底动脉(BA)、左椎动脉(LVA)、右椎动脉(RVA)的收缩峰流速差异无统计学意义(P>0.05);在治疗4周后,两组间差异有统计学意义(P<0.05)。组内比较,两组在治疗2周后和治疗4周后BA、LVA、RVA的收缩峰流速较治疗前差异有统计学意义(P<0.05),并且治疗4周后较治疗2周后差异也有统计学意义(P<0.05)。治疗组总有效率为93.75%,对照组总有效率为74.19%,差异有统计学意义(P<0.05)。结论针刺联合耳穴压籽法和针刺法均可有效加快脑血流速度、改善PCIV患者的眩晕程度,减少PCIV导致的功能障碍,且针刺联合耳穴压籽法的疗效较单纯针刺法更为显著;该试验进行和随访期间不良反应发生率为1.49%,总体安全性良好。

Climate-Vegetation Coverage Interactions in the Hengduan Mountains Area, Southeastern Tibetan Plateau, and Their Downstream Effects

Little is known about the mechanism of climate-vegetation coverage coupled changes in the Tibetan Plateau(TP)region,which is the most climatically sensitive and ecologically fragile region with the highest terrain in the world.This study,using multisource datasets(including satellite data and meteorological observations and reanalysis data)revealed the mutual feedback mechanisms between changes in climate(temperature and precipitation)and vegetation coverage in recent decades in the Hengduan Mountains Area(HMA)of the southeastern TP and their influences on climate in the downstream region,the Sichuan Basin(SCB).There is mutual facilitation between rising air temperature and increasing vegetation coverage in the HMA,which is most significant during winter,and then during spring,but insignificant during summer and autumn.Rising temperature significantly enhances local vegetation coverage,and vegetation greening in turn heats the atmosphere via enhancing net heat flux from the surface to the atmosphere.The atmospheric heating anomaly over the HMA thickens the atmospheric column and increases upper air pressure.The high pressure anomaly disperses downstream via the westerly flow,expands across the SCB,and eventually increases the SCB temperature.This effect lasts from winter to the following spring,which may cause the maximum increasing trend of the SCB temperature and vegetation coverage in spring.These results are helpful for estimating future trends in climate and eco-environmental variations in the HMA and SCB under warming scenarios,as well as seasonal forecasting based on the connection between the HMA eco-environment and SCB climate.

Bilayer separator enabling dendrite-free zinc anode with ultralong lifespan >5000 h

Aqueous zinc(Zn)batteries with Zn metal anodes are promising clean energy storage devices with intrinsic safety and low cost.However,Zn dendrite growth severely restricts the use of Zn anodes.To effectively suppress Zn dendrite growth,we propose a bilayer separator consisting of commercial butter paper and glassfiber membrane.The dense cellulose-based butter paper(BP)with low zincophilicity and high mechanical properties prevents the pore-filling behavior of deposited Zn and related separator piercing,effectively suppressing the Zn dendrite growth.As a result,the bilayer separators endow the ZnjjZn symmetrical batteries with a superlong cycling life of Zn anodes(over 5000 h)at 0.5 mA cm^(-2) and the full batteries enhanced capacity retention,demonstrating the advancement of the bilayer separator to afford excellent cyclability of aqueous metal batteries.

Static-to-kinematic modeling and experimental validation of tendon-driven quasi continuum manipulators with nonconstant subsegment stiffness

Continuum robots with high flexibility and compliance have the capability to operate in confined and cluttered environments. To enhance the load capacity while maintaining robot dexterity, we propose a novel non-constant subsegment stiffness structure for tendon-driven quasi continuum robots(TDQCRs) comprising rigid-flexible coupling subsegments.Aiming at real-time control applications, we present a novel static-to-kinematic modeling approach to gain a comprehensive understanding of the TDQCR model. The analytical subsegment-based kinematics for the multisection manipulator is derived based on screw theory and product of exponentials formula, and the static model considering gravity loading,actuation loading, and robot constitutive laws is established. Additionally, the effect of tension attenuation caused by routing channel friction is considered in the robot statics, resulting in improved model accuracy. The root-mean-square error between the outputs of the static model and the experimental system is less than 1.63% of the arm length(0.5 m). By employing the proposed static model, a mapping of bending angles between the configuration space and the subsegment space is established. Furthermore, motion control experiments are conducted on our TDQCR system, and the results demonstrate the effectiveness of the static-to-kinematic model.

LociScan,a tool for screening genetic marker combinations for plant variety discrimination

To reduce the cost and increase the efficiency of plant genetic marker fingerprinting for variety discrimination,it is desirable to identify the optimal marker combinations.We describe a marker combination screening model based on the genetic algorithm(GA)and implemented in a software tool,Loci Scan.Ratio-based variety discrimination power provided the largest optimization space among multiple fitness functions.Among GA parameters,an increase in population size and generation number enlarged optimization depth but also calculation workload.Exhaustive algorithm afforded the same optimization depth as GA but vastly increased calculation time.In comparison with two other software tools,Loci Scan accommodated missing data,reduced calculation time,and offered more fitness functions.In large datasets,the sample size of training data exerted the strongest influence on calculation time,whereas the marker size of training data showed no effect,and target marker number had limited effect on analysis speed.

Clinical features and prognostic factors of duodenal neuroendocrine tumours:A comparative study of ampullary and nonampullary regions

BACKGROUND Duodenal neuroendocrine tumours(DNETs)are rare neoplasms.However,the incidence of DNETs has been increasing in recent years,especially as an incidental finding during endoscopic studies.Regrettably,there is no consensus regarding the ideal treatment of DNETs.Even there are few studies on the clinical features and survival analysis of DNETs.AIM To analyze the clinical characteristics and prognostic factors of patients with duodenal neuroendocrine tumours.METHODS The clinical data of DNETs diagnosed in the First Affiliated Hospital of Air Force Military Medical University from June 2011 to July 2022 were collected.Neuroen-docrine tumours located in the ampulla area of the duodenum were divided into the ampullary region group;neuroendocrine tumours in any part of the duo-denum outside the ampullary area were divided into the nonampullary region group.Using a retrospective study,the clinical characteristics of the two groups and risk factors affecting the survival of DNET patients were analysed.RESULTS Twenty-nine DNET patients were screened.The male to female ratio was 1:1.9,and females comprised the majority.The ampullary region group accounted for 24.1%(7/29),while the nonampullary region group accounted for 75.9%(22/29).When diagnosed,the clinical symptoms of the ampullary region group were mainly abdominal pain(85.7%),while those of the nonampullary region groups were mainly abdominal distension(59.1%).There were differences in the composition of staging of tumours between the two groups(Fisher's exact probability method,P=0.001),with nonampullary stage II tumours(68.2%)being the main stage(P<0.05).After the diagnosis of DNETs,the survival rate of the ampullary region group was 14.3%(1/7),which was lower than that of 72.7%(16/22)in the nonampullary region group(Fisher's exact probability method,P=0.011).The survival time of the ampullary region group was shorter than that of the nonampullary region group(P<0.000).The median survival time of the ampullary region group was 10.0 months and that of the nonampullary region group was 451.0 months.Multivariate analysis showed that tumours in the ampulla region and no surgical treatment after diagnosis were independent risk factors for the survival of DNET patients(HR=0.029,95%CI 0.004-0.199,P<0.000;HR=12.609,95%CI:2.889-55.037,P=0.001).Further analysis of nonampullary DNET patients showed that the survival time of patients with a tumour diameter<2 cm was longer than that of patients with a tumour diameter≥2 cm(t=7.243,P=0.048).As of follow-up,6 patients who died of nonampullary DNETs had a tumour diameter that was≥2 cm,and 3 patients in stage IV had liver metastasis.Patients with a tumour diameter<2 cm underwent surgical treatment,and all survived after surgery.CONCLUSION Surgical treatment is a protective factor for prolonging the survival of DNET patients.Compared to DNETs in the ampullary region,patients in the nonampullary region group had a longer survival period.The liver is the organ most susceptible to distant metastasis of nonampullary DNETs.

液相色谱-串联质谱法快速测定化妆品中游离的乙醇胺类物质

建立稳定同位素稀释-液相色谱-串联质谱法(LC-MS/MS)测定化妆品中游离的3种乙醇胺类物质。样品经异丙醇提取后,使用乙腈和0.1%甲酸-水溶液(体积分数,下同)梯度洗脱,Kinetex HILIC色谱柱分离,电喷雾电离源正离子模式电离,多反应监测模式进行测定。采用单因素试验优化得到最佳前处理条件:提取溶剂为异丙醇、超声波提取、提取时间为20 min、不改变样品pH直接提取。使用内标法曲线定量,一乙醇胺、二乙醇胺和三乙醇胺内标曲线分别在5.0~200,2.0~200和1.0~200μg/L范围内线性关系良好,相关系数R^(2)大于0.999,平均回收率范围在87.1%~97.0%,相对标准偏差(RSDs)在1.68%~6.57%之间,方法检出限为3.00~15.0μg/kg,定量限为10.0~50.0μg/kg。建立的方法适用于61批次化妆品样品的检测。该方法操作简便,定量准确,回收率稳定、灵敏度高、精密度高,适用于测定化妆品中的乙醇胺类物质。

Wave nature of Rosensweig instability

The explicit analytical solution of Rosensweig instability spikes'shapes obtained by Navier-Stokes(NS)equation in diverse magnetic field H vertical to the flat free surface of ferrofluids are systematically studied experimentally and theoretically.After carefully analyzing and solving the NS equation in elliptic form,the force balanced surface equations of spikes in Rosensweig instability are expressed as cosine wave in perturbated magnetic field and hyperbolic tangent in large magnetic field,whose results both reveal the wave-like nature of Rosensweig instability.The results of hyperbolic tangent form are perfectly fitted to the experimental results in this paper,which indicates that the analytical solution is basically correct.Using the forementioned theoretical results,the total energy of the spike distribution pattern is calculated.By analyzing the energy components under different magnetic field intensities H,the hexagon-square transition of Rosensweig instability is systematically discussed and explained in an explicit way.