Endoscopic treatment of extreme esophageal stenosis complicated with esophagotracheal fistula: A case report

BACKGROUND At present,there is no unified and effective treatment for extreme corrosive esophageal stenosis(CES)with esophagotracheal fistula(ETF).This case had extreme and severe esophageal stenosis(ES)and ETF after ingesting an enzyme-based chemical detergent,resulting in a serious pulmonary infection and severe malnutrition.Upper gastrointestinal imaging showed that he had an ETF,and endoscopy showed that he had extreme and severe esophageal stricture.This case was complex and difficult to treat.According to the domestic and foreign lite-rature,there is no universal treatment that is low-risk.CASE SUMMARY A patient came to our hospital with extreme ES,an ETF,and severe malnutrition complicated with pulmonary tuberculosis 1 mo after the consumption of an enzy-me-based detergent.The ES was serious,and the endoscope was unable to pass through the esophagus.We treated him by endoscopic incision method(EIM),esophageal stent placement(ESP),and endoscopic balloon dilation(EBD)by using the bronchoscope and gastroscope.This treatment not only closed the ETF,but also expanded the esophagus,with minimal trauma,greatly reducing the pain of the patient.According to the literature,there are no similar reported cases.CONCLUSION We report,for the first time,a patient with extreme CES complicated with ETF,where the endoscope could not be passed through his esophagus but he could be examined by bronchoscopy and treated by EIM,ESP,and EBD.

Comparison of total splenic artery embolization and partial splenic embolization for hypersplenism

AIM:To evaluate whether total splenic artery embolization(TSAE) for patients with hypersplenism delivers better long-term outcomes than partial splenic embolization(PSE).METHODS:Sixty-one patients with hypersplenism eligible for TSAE(n = 27,group A) or PSE(n = 34,group B) were enrolled into the trial,which included clinical and computed tomography follow-up.Data on technical success,length of hospital stay,white blood cell(WBC) and platelet(PLT) counts,splenic volume and complications were collected at 2 wk,6 mo,and 1,2,3,4 years postoperatively.RESULTS:Both TSAE and PSE were technically successful in all patients.Complications were significantly fewer(P = 0.001),and hospital stay significantly shorter(P = 0.007),in group A than in group B.Postprocedure WBC and PLT counts in group A were significantly higher than those in group B from 6 mo to 4 years(P = 0.001),and post-procedure residual splenic volume in group A was significantly less than that observed in group B at 1,2,3 and 4 years post-procedure(P = 0.001).No significant differences were observed in red blood cell counts and liver function parameters between the two groups following the procedure.CONCLUSION:Our results indicate that TSAE for patients with hypersplenism not only delivers a better longterm outcome,but is also associated with lower complication rates and a shorter hospital stay than PSE.

Total embolization of the main splenic artery as a supplemental treatment modality for hypersplenism

AIM:To study the safety and feasibility of total embolization of the main splenic artery as a supplemental treatment modality for hypersplenism with thrombocytopenia or leukocytopenia accompanying liver cirrhosis.METHODS:Fifteen consecutive patients with hypersplenism due to cirrhosis were enrolled in this study from January 2006 to June 2010.All patients underwent total embolization of the main splenic artery.Clinical symptoms,white blood cell(WBC) and platelet(PLT) counts,splenic volume,and complications of the patients were recorded.The patients were followed up for 1 and 6 mo,and 1,2,3 years,respectively,after operation.RESULTS:Total embolization of the main splenic artery was technically successful in all patients.Minor complications occurred in 13 patients after the procedure,but no major complications were found.The WBC andPLT counts were significantly higher and the residual splenic volume was significantly lower 1 and 6 mo,and 1,2,3 years after the procedure than before the procedure(P < 0.01).Moreover,the residual splenic volume increased very slowly with the time after embolization.All patients were alive during the follow-up period.CONCLUSION:Total embolization of the main splenic artery is a safe and feasible procedure and may serve as a supplemental treatment modality for hypersplenism with thrombocytopenia or leukocytopenia accompanying liver cirrhosis.

Influence of high concentration Zn^(2+) on floatability of sphalerite in acidic system

The influence of high concentration Zn^(2+) on the floatability of sphalerite in an acidic system was investigated via flotation experiments,zeta potential measurements,contact angle measurements,and X-ray photoelectron spectroscopy.The results indicated that Zn^(2+) was adsorbed on the sphalerite surface and a Zn-hydroxyl complex was formed at a pH of 4 and a Zn^(2+) concentration of 4×10^(-2) mol/L.The zeta potential increased and the contact angle decreased from 84.80°to 36.48°,strongly inhibiting the floatability of sphalerite.When S^(2−) or Cu^(2+) activator was used alone,sphalerite was not activated after Zn^(2+) was adsorbed,and its contact angle did not change significantly.However,by using a combination of S^(2−) and Cu^(2+) activators,its floatability was realized after Zn^(2+) adsorption.This result was attributed to the removal of the Zn-hydroxyl complex on the surface of sphalerite by S^(2-).After this removal,Cu^(2+) was adsorbed on the sphalerite surface to form a Cu_(2)S·S^(0) hydrophobic film.

双倍剂量链霉蛋白酶联合西甲硅油改善胃内清洁度的临床研究

背景胃清洁度是影响胃镜检查质量的重要因素.链霉蛋白酶是一种蛋白分解酶,可切断胃粘膜中的黏蛋白肽键,提高胃清洁度.双倍剂量的链霉蛋白酶可充分发挥祛除黏液疗效,联合西甲硅油可进一步提升胃内视野.目的探讨双倍剂量链霉蛋白酶联合西甲硅油在改善胃镜检查胃内清洁度方面的疗效和安全性.方法采用随机对照的方法,将126例接受胃镜检查的患者分为三组:不含链霉蛋白酶的对照组、单倍剂量链霉蛋白酶组和双倍剂量链霉蛋白酶组.观察各组在检查时胃内不同部位的清洁度、内镜操作时间、病灶检出率及不良反应等指标.结果与对照组相比,双倍链霉蛋白酶组的胃内清洁度评分更高(P<0.01),内镜操作时间更短(P<0.01),但病灶检出率没有显著差异.同时,各组在不良反应发生率上也没有显著差异(P>0.05).结论双倍剂量链霉蛋白酶优于单倍剂量链霉蛋白酶作为胃镜检查术前准备药物,能够明显改善胃内清洁度,减少内镜操作时间,并且具有较高的安全性.

葛根素通过上调Nrf2通路缓解小鼠非酒精性脂肪性肝炎

背景非酒精性脂肪性肝炎(nonalcoholic steatohepatitis,NASH)发病率呈上升趋势,炎症和氧化应激是该疾病进展的关键.葛根素有抗炎和抗氧化的活性,葛根素对小鼠非酒精性脂肪性肝炎的作用及其机制尚无定论.目的探讨葛根素对非酒精性脂肪性肝炎的改善效应及其机制.方法采用蛋氨酸胆碱缺乏饮食构造小鼠非酒精性脂肪性肝炎模型.C57BL/6小鼠随机分为正常饮食组,模型组,葛根素组.三种饮食分别予以正常饮食、蛋氨酸胆碱缺乏饮食、蛋氨酸胆碱缺乏饮食加葛根素喂养4 wk;收集血清和肝脏标本以检测组织学变化、炎症指标、肝功能、氧化应激相关指标.结果与正常组比较,模型组小鼠肝脏甘油三酯和胆固醇均有升高,H&E染色结果显示肝脏出现明显脂肪变性和炎症反应以及纤维化.与正常组相比,模型组抗氧化因子谷胱甘肽和超氧化物歧化酶活性显著降低,脂质过氧化标志物丙二醛是显著升高的.与模型组比较,葛根素组小鼠肝脏中甘油三酯和胆固醇明显降低(P<0.05),炎症因子如肿瘤坏死因子α及白介素1β明显降低(P<0.05),小鼠肝脏中纤维化基因αSMA、PAI-1、COL1A1、TGFβ表达明显降低(P<0.05),血清谷丙转氨酶和谷草转氨酶明显降低(P<0.05).与模型组相比,葛根素组中谷胱甘肽和超氧化物歧化酶活性显著升高,丙二醛显著降低,细胞核内转录因子NF-E2相关因子2(NF-E2-related factor 2,Nrf2)及其靶基因血红素加氧酶-1(hemeoxygenase-1,HO-1)表达是升高的(P<0.05).结论葛根素对蛋氨酸胆碱缺乏饮食诱导的非酒精性脂肪性肝炎有显著改善作用,其机制可能与其抑制炎症、抑制纤维化以及上调Nrf2通路有关.本研究为深入了解NASH的发病机制提供了新的思路,并为葛根素作为抗NASH的潜在药物提供了进一步的证据.

A robust luminescent assay for screening alkyladenine DNA glycosylase inhibitors to overcome DNA repair and temozolomide drug resistance

Temozolomide(TMZ)is an anticancer agent used to treat glioblastoma,typically following radiation therapy and/or surgical resection.However,despite its effectiveness,at least 50%of patients do not respond to TMZ,which is associated with repair and/or tolerance of TMZ-induced DNA lesions.Studies have demonstrated that alkyladenine DNA glycosylase(AAG),an enzyme that triggers the base excision repair(BER)pathway by excising TMZ-induced N3-methyladenine(3meA)and N7-methylguanine lesions,is overexpressed in glioblastoma tissues compared to normal tissues.Therefore,it is essential to develop a rapid and efficient screening method for AAG inhibitors to overcome TMZ resistance in glioblastomas.Herein,we report a robust time-resolved photoluminescence platform for identifying AAG inhibitors with improved sensitivity compared to conventional steady-state spectroscopic methods.As a proof-of-concept,this assay was used to screen 1440 food and drug administration-approved drugs against AAG,resulting in the repurposing of sunitinib as a potential AAG inhibitor.Sunitinib restored glioblastoma(GBM)cancer cell sensitivity to TMZ,inhibited GBM cell proliferation and stem cell characteristics,and induced GBM cell cycle arrest.Overall,this strategy offers a new method for the rapid identification of small-molecule inhibitors of BER enzyme activities that can prevent false negatives due to a fluorescent background.

Acute exacerbation of idiopathic pulmonary fibrosis treated using the Feibi recipe:Two case reports

BACKGROUND Rationale:No other treatment besides lung transplant is effective for idiopathic pulmonary fibrosis(IPF).Patients with IPF have poor prognosis,which may eventually lead to death.Patient concerns:Two female patients were diagnosed with IPF.In our recent follow-up,both these patients maintained a good quality of life.CASE SUMMARY Diagnosis:Both patients had dry cough and progressive dyspnea.Interventions:The first patient was treated with prednisone,and the second patient was treated with prednisone and tripterygium glycosides.However,the symptoms did not improve and fibrosis was not controlled.Thus,the Feibi recipe was used.Outcomes:No deterioration was observed after the treatment,and the dry cough and its effect were ameliorated.Furthermore,they are still alive and the quality of their lives has improved.CONCLUSION These two cases suggest that the Feibi recipe and other traditional Chinese medicine therapies could be beneficial for IPF treatment.

Heat shock pretreatment improves stem cell repair following ischemia-reperfusion injury via autophagy

AIM: To investigate whether heat shock pretreatment(HSP) improves mesenchymal stem cell(MSC) repair via autophagy following hepatic ischemia-reperfusion injury(HIRI).METHODS: Apoptosis of MSCs was induced by 250 m M hydrogen peroxide(H2O2) for 6 h. HSP was carried out using a 42 ℃ water bath for 1, 2 or 3 h. Apoptosis of MSCs was analyzed by flow cytometry, and Western blot was used to detect Bcl-2, Bax and cytochrome C expression. Autophagy of MSCs was analyzed by flow cytometry and transmission electron microscopy, and the expression of beclin Ⅰ?and LC3-Ⅱ was detected by Western blot. MSCs were labeled in vivo with the fluorescent dye, CM-Dil, and subsequently transplanted into the portal veins of rats that had undergone HIRI. Liver levels of proliferating cell nuclear antigen(PCNA) were quantified by fluorescent microscopy. Serum aminotransferase activity and the extent of HIRI were also assessed at each time point.RESULTS: HSP for 2 h reduced apoptosis of MSCs induced by H2O2 as seen by a decrease in apoptotic rate, a decrease in Bax and cytochrome C expression and an increase in Bcl-2 expression(P < 0.001). In addition, HSP for 2 h induced autophagy of MSCs exposed to H2O2 as shown by an increase in acidic vesicular organelle-positive cells, beclin 1 and LC3-Ⅱ expression, and autophagosome formation(P < 0.05). Treatment with 3-methyladenine attenuated HSPinduced autophagy and abolished the protective effects of HSP on the apoptosis of MSCs. Rapamycin failed to have additional effects on either autophagy or apoptosis compared with HSP alone. The phosphorylation of p38 MAPK was significantly elevated and the phosphorylation of m TOR was downregulated in heat shock pretreated MSCs. Treatment with the p38 MAPK inhibitor, SB203580, reduced HSP-induced autophagy in MSCs. In vivo studies showed that the transplantation of HSP-MSCs resulted in lower serum aminotransferase levels, lower Suzuki scores, improved histopathology and an increase in PCNA-positive cells(P < 0.05).CONCLUSION: HSP effectively induces autophagy following exposure to H2O2 via the p38MAPK/m TOR pathway, which leads to enhanced MSC survival and improved MSC repair following HIRI in rats.

New-style laparoscopic and endoscopic cooperative surgery for gastric stromal tumors

AIM: To evaluate the feasibility and safety of a new style of laparoscopic and endoscopic cooperative surgery (LECS), an improved method of laparoscopic intragastric surgery (LIGS) for the treatment of gastric stromal tumors (GSTs). METHODS: Six patients were treated with the newstyle LECS. Surgery was performed according to the following procedures: (1) Exposing and confirming the location of the tumor with gastroscopy; (2) A laparoscopy light was placed in the cavity using the trocar at the navel, and the other two trocars penetrated both the abdominal and stomach walls; (3) With gastroscopy monitoring, the operation was carried out in the gastric lumen using laparoscopic instruments and the tumor was resected; and (4) The tumor tissue was removed orally using a gastroscopy basket, and puncture holes and perforations were sutured using titanium clips. RESULTS: Tumor size ranged from 2.0 to 4.5 cm (average 3.50 ± 0.84 cm). The operative time ranged from 60 to 130 min (average 83.33 ± 26.58 min). Blood loss was less than 20 mL and hospital stay ranged from 6 to 8 d (average 6.67 ± 0.82 d). The patients were allowed out of bed 12 h later. A stomach tube was inserted for 72 h after surgery, and a liquid diet was then taken. All cases had single tumors which were completely resected using the new-style LECS. No postoperative complications occurred. Pathology of all resected specimens showed GST: no cases of implantation or metastasis were found.CONCLUSION: New-style LECS for GSTs is a quick, optimized, fast recovery, safe and effective therapy.

Efficient acidic oxygen evolution reaction electrocatalyzed by iridium-based 12L-perovskites comprising trinuclear face-shared IrO6 octahedral strings

Development of cost-effective and highly active oxygen evolution catalysts operating well in acidic media is a critical challenge in proton exchange membrane water electrolysis.Herein,we present a class of iridium-based 12L-perovskites(Ba4MIr3O12;M=Pr,Bi,Nb)as novel low-iridium electrocatalysts for oxygen evolution reaction under acidic conditions.These 12L-perovskites contain trinuclear face-shared Ir O6octahedral strings—unique subunits that are not found in the previously-reported iridium-based electrocatalysts.The catalytic activities of 12L-perovskites(Ba4MIr3O12)are found to be related to the location of O 2p-band center,which is influenced by the B-site nonprecious element(i.e.,Pr,Bi or Nb).Our experimental results show that Ba4PrIr3O12is the most active electrocatalyst among the materials we synthesize,and contains 55%less iridium than the benchmark catalyst IrO2,while exhibiting higher catalytic activity.In the presence of Ba4PrIr3O12,transient leaching process of Ba and Pr takes place during electrochemical process,contributing to the surface reconstruction of the pristine catalysts.Further experimental results reveal that the formation of under-coordinated Ir Ox-rich surface and easier generation of active intermediate IrVare mainly responsible for the good activity of Ba4PrIr3O12.

Comparative chloroplast genome analysis of medicinally important Veratrum(Melanthiaceae)in China:Insights into genomic characterization and phylogenetic relationships

Members of Veratrum are perennial herbs widely used in traditional Chinese medicine to induce vomiting,resolve blood stasis and relieve pain.However,the intrageneric classification and phylogenetic relationships within Veratrum have long been controversial due to the complexity of morphological variations and lack of high-resolution molecular markers.In this study,we reevaluated the infrageneric relationships with the genus Veratrum using complete chloroplast genome sequence data.Herein,the complete cp genomes of ten species of Veratrum were newly sequenced and characterized.The complete cp genomes of ten species of Veratrum had the typical quadripartite structure,ranging from 151,597 bp to 153,711 bp in size and comprising a total of 135 genes.The structure of Veratrum cp genomes(i.e.,gene order,content,and genome components)was highly similar across species.The number of simple sequence repeats(SSRs)ranged from 63 to 7&and of long repeats ranged from 31 to 35.Eight highly divergent regions(ndhF,psbC-psbZ,psbK-psbl,rpoB-tmCjGCA,tmK_UUU-tmQ_UUG,tmS_GCU-tmG_UCC,tmT_UGU-tmL_UAA and ycfl)were identified and are potentially useful for the DNA barcoding of Veratrum.Phylogenetic analysis among 29 taxa based on cp genomes,total genes,protein-coding genes and intergenic regions strongly supported the monophyly of Veratrum.The circumscription and relationships of the infrageneric taxa of Veratrum were well-presented with great resolution.These results will facilitate the identification,taxonomy,and utilization of Veratrum plants as well as the evolutionary studies of Melanthiaceae.

Image-guidedcryoablation in unresectable or recurrent advanced colorectal cancer:a retrospective study

Purpose: The present study retrospectively analyzed thesafety and efficacy of computed tomography(CT)-guided cryoablationin the treatment ofunresectable or recurrent advanced colorectal cancer, which did not respond well to or experienced progression with radiotherapy or chemotherapy. Materials and Methods: From January 2013 to April 2015, 31 lesions in 27 patients(16 males, 11 females; mean age of 57.2 years) with pelvic unresectableadvanced or recurrent colorectal cancer were included in the study.The tumor diameter was approximately 3.37 ±1.41 cm. The primary tumor included 25 rectal cancers, 1 sigmoid colon adenocarcinoma, and 1 ileocecal mucinous adenocarcinoma. Cryoablation was performed with 17-gauge cryoprobes and monitored by 64-slice spiral CT. Follow-up was carried out by contrast-enhanced magnetic resonance imaging(MRI). The treatment efficacy was evaluated by symptom palliation, decreased carcinoembryonic antigen(CEA) serum level, and tumor response. Results: The cryoablation procedure was well-tolerated in all patients without major complications or procedure-related mortality. Long-term complications included abscess formation(1 patient), skin frostbite and post-sacrum antrum formation(1 patient). Pain relief was satisfactory in patients with perineal pain(P<0.001), and the median time of pain relief was 3.0 months. Complete ablations were obtained in 22 lesions of 18 patients, while 9 lesions in 9 patients underwent incomplete ablation. The median time to local recurrence for lesions with complete ablations was 15.0 months, and that to the progression of tumors with incomplete ablation was 4.0 months. Conclusion: CT-guided cryoablation is a minimally invasive, safe, and effective therapeutic option for unresectableadvanced or recurrent colorectal cancer. The treatment is well-tolerated by patients, and pain relief is achieved rapidly.

Laparoscopic-assisted endoscopic full-thickness resection of a large gastric schwannoma: A case report

BACKGROUND Schwannomas,also known as neurinomas,are benign tumors derived from Schwann cells.Gastrointestinal schwannomas are rare and are most frequently reported in the stomach.They are usually asymptomatic and are difficult to diagnose preoperatively;however,endoscopy and imaging modalities can provide beneficial preliminary diagnostic data.There are various surgical options for management.Here,we present a case of a large gastric schwannoma(GS)managed by combined laparoscopic and endoscopic surgery.CASE SUMMARY A 28-year-old woman presented with a 2-mo history of epigastric discomfort and a feeling of abdominal fullness.On upper gastrointestinal endoscopy and endoscopic ultrasonography,a hypoechogenic submucosal mass was detected in the gastric antrum:It emerged from the muscularis propria and projected intraluminally.Computed tomography showed a nodular lesion(4 cm×3.5 cm),which exhibited uniform enhancement,on the gastric antrum wall.Based on these findings,a preliminary diagnosis of gastrointestinal stromal tumor was established,with schwannoma as a differential.Considering the large tumor size,we planned to perform endoscopic resection and to convert to laparoscopic treatment,if necessary.Eventually,the patient underwent combined laparoscopic and gastroscopic surgery.Immunohistochemically,the resected specimen showed positivity for S-100 and negativity for desmin,DOG-1,α-smooth muscle actin,CD34,CD117,and p53.The Ki-67 index was 3%,and a final diagnosis of GS was established.CONCLUSION Combined laparoscopic and endoscopic surgery is a minimally invasive and effective treatment option for large GSs.

Studying infall in infrared dark clouds with multiple HCO transitions

We investigate the infall properties in a sample of 11 infrared dark clouds(IRDCs) showing blue-asymmetry signatures in HCO^(+)J=1-0 line profiles.We used JCMT to conduct mapping observations in HCO^(+)J=4-3 as well as single-point observations in HCO+J=3-2,towards 23 clumps in these IRDCs.We applied the HILL model to fit these observations and derived infall velocities in the range of 0.5-2.7 km s^(-1),with a median value of 1.0 km s^(-1),and obtained mass accretion rates of 0.5-14 ×10^(-3) Mo yr^(-1).These values are comparable to those found in massive star forming clumps in later evolutionary stages.These IRDC clumps are more likely to form star clusters.HCO^(+)J=3-2 and HCO^(+)J=1-0 were shown to trace infall signatures well in these IRDCs with comparable inferred properties.HCO^(+)J=4-3,on the other hand,exhibits infall signatures only in a few very massive clumps,due to smaller opacities.No obvious correlation for these clumps was found between infall velocity and the NH3/CCS ratio.

Functional identification of bHLH transcription factor MdSAT1 in the ammonium response

Plants mainly uptake inorganic nitrogen from soil as ammonium and nitrate.Less energy is required to assimilate ammonium compared to nitrates,and plants prefer to take up ammonium when the external nitrogen concentration is low.Investigating the patterns and mechanisms of ammonium absorption can help improve crop nitrogen utilization.In this study,we isolated MdSAT1,a gene of apple encoding an ammoniumresponsive bHLH transcription factor.MdSAT1 promoted the growth and development of lateral roots and root hairs.Overexpression of MdSAT1 increased the transcript levels of genes related to ammonium uptake,indicating that MdSAT1 can regulate ammonium uptake and utilization at the transcriptional level.MdSAT1 also can modulate reactive oxygen species(ROS)accumulation to ultimately regulate plant growth.Taken together,these findings provide insight for us to further study the mechanisms by which MdSAT1 controls ammonium utilization as well as plant growth and development.

Air-core characteristics in a swirling tunnel flow

A cost-effective technique to dissipate the energy in hydropower systems is the formation of a swirling flow within a tunnel.In such flows,an air core with a significant cross section usually occurs.To reveal the air-core features in the horizontal tunnel of a high-head shaft spillway,laboratory tests,numerical modeling,and prototype observations are performed,to examine issues such as the formation of the air core,the interjacent air motion,the air-carrying capacity,and the scale effects.It is shown that the shape of the air core varies greatly in the axial and radial directions along the tunnel and that the center of the core deviates from the axis of the tunnel.The motion of the air within the core is caused by the combined action of the water entrainment on the inner surface of the swirling flow and the axial pressure difference in the air core.The aeration process can be divided into five processes with respect to the changes of the gate openings.A theoretical expression is established for the air-carrying capacity of the swirling flow.The vacuum degree is the similarity condition of the air-carrying capacity of the swirling flow between the model and prototype tests based on the Froude law of the similitude,and this similarity condition is verified by both the model and prototype results.This work provides a reference for the application of the swirling flows in horizontal hydropower tunnels.

Tunable hydrogen coverage on electron-deficient platinum nanoparticles for efficient hydrogenation reactions

Dissociation of active H species over the catalytic sites with the carbon-supported Pt metals as the mainstream catalysts is crucial to facilitate hydrogen donation and accelerate the hydrogen addition process in catalytic hydrogenation systems to produce polymers,pharmaceuticals,agrochemicals,fragrances,and biofuels at million-ton scale.Much attention has been paid to the design of the more active catalytic site to effectively adsorb and activate reactants and H_(2) molecules.At the same time,there is still a huge room to develop powerful strategies to accelerate the donation of acted H species to the reactants from the Pt surface further to boost the final catalytic efficiencies of Pt catalysts and depress the total Pt consumption.Herein,we present a new strategy for promoting the Pt-H bond dissociation by increasing surface hydrogen coverage on designed electron-deficient Pt nanoparticles.The electron deficiency of Pt nanoparticles has been successfully tuned by constructing a rectifying contact with an even“noble”boron-rich carbon support(Pt/BC).Theoretical and experimental results confirm the dominant role of the pronounced electron deficiencies of Pt nanoparticles in enhancing the H coverage for 2.3 times higher than that of neutral Pt nanoparticles,significantly boosting the Pt-H bond dissociation and thus the whole hydrogenation process as reflected by the extremely high turnover frequency(TOF)value of 388 h^(-1)at 30℃ and 10 bar H_(2) for phenol hydrogenation on the Pt/BC,outperforming the bench-marked catalysts by a factor of 9.

慢性萎缩性胃炎胃癌风险的列线图预测模型:血细胞比值的作用

背景慢性萎缩性胃炎(chronic atrophic gastritis,CAG)是胃癌的癌前病变.虽然内镜检查是监测CAG的标准方法,但其有侵入性且价格较贵,这些特点限制了其广泛使用.因此需要早期识别CAG人群胃癌风险.目的本研究旨在识别CAG人群中胃癌的风险因素,重点关注血细胞比值,建立能够量化CAG癌变风险的个性化预测模型.方法回顾性纳入2018-01/2024-01期间在杭州师范大学附属医院所收治的经内镜和病理判断存在CAG患者,筛选其中符合入组标准的患者,共计314例作为此次研究对象.记录人口学信息、血清学参数和血细胞指标.通过多因素逻辑回归确定独立危险因素,并使用R语言构建列线图模型.通过ROC曲线下面积(area under the ROC curve,AUC)、Hosmer-Lemeshow检验和决策曲线分析(decision curve analysis,DCA)评价模型区分度、校准度及有效性.结果在CAG人群中,男性(OR=2.214,P<0.05)、幽门螺杆菌(Helicobacter pylori,H.pylori)感染(OR=2.686,P<0.05)、促胃泌素17(gastrin 17,G-17)(OR=1.037,P<0.05)、血红蛋白与红细胞分布宽度比值(hemoglobin-to-red blood cell distribution width ratio,HRR)(OR=0.648,P<0.05)、淋巴细胞与单核细胞比值(lymphocyte-to-monocyte ratio,LMR)(OR=0.645,P<0.05)是癌变的独立预测因素(P<0.05).基于性别、H.pylori感染、G-17、HRR、LMR 5项指标建立慢性萎缩性胃炎人群癌变风险预测列线图模型,计算模型的AUC为0.854(95%CI:0.8105-0.8967),Hosmer-Lemeshow拟合优度检验显示χ2=6.062,P=0.640(P>0.05),说明预测概率与实际观测值具有良好的一致性,DCA曲线显示模型阈概率在0到70%区间内,说明模型具有潜在的泛化能力.结论该列线图为CAG患者提供了一种无创、便捷且经济有效的胃癌筛查工具,具有出色的区分度和校准能力.需要进一步开展大规模、多中心的研究,以验证其在不同人群中的有效性.

基于TVD框架的Godunov格式水锤求解模型

求解有压管道系统水锤波时,传统特征线法及有限差分法受Courant数约束,会导致计算速度低,且因多波插值,存在插值误差问题。该文通过搭构TVD框架、分析并选取最优限制函数以及优化管网分叉口处理方法的方式,提出了一种基于Godunov格式的两阶有限体积格式管网水锤计算模型,并通过管网算例对模型计算效率进行了对比。结果表明:有限体积法在低Courant数时能得到最佳的计算结果,与特征线法及Sweby TVD差分法相比,计算耗时分别节省了28.6%及85.3%;模型选取Van Leer限制器,Courant数值范围为0.2≤Cr≤0.5;模型在网格划分上更为灵活,可根据实际需求选取满足Courant数范围的任意网格间距,实现对变空间步长管网系统瞬变流的高效计算。