Synthesis, performance and structure characterization of glyoxal-monomethylolurea-melamine (G-MMU-M) co-condensed resin

In order to reduce the formaldehyde emission of formaldehyde-based wood adhesive from the source,it is aimed to develop a novel co-condensed resin of glyoxal-monomethylolurea-melamine(G-MMU-M).A series of G-MMU-M resins with various formulations of raw materials were successfully prepared.The basic properties and bonding performance of the G-MMU-M resins were determined.Furthermore,the structures of resins were characterized by FTIR,^(13)C NMR,XPS,and ESI-MS.The results show that the prepared G-MMU-M resin remains stable for 30 d,meanwhile,the dry and wet bonding strength of the plywoods bonded with the resins,solid content and viscosity are influenced greatly by the addition amount of melamine and MMU/G molar ratio.The G-MMU-M resins with MMU/G molar ratio of 0.9:1.0 and 8% melamine exhibit the highest dry and bonding strength of 1.98 MPa and 1.27 MPa,increased by 34% and 63%,respectively,in comparison with glyoxal-monomethylolurea(G-MMU)resin.In the G-MMU-M resins,there were four main oligomers including M—CH(—^(+)CH-MMU)-O-MMU,M-CH(—CH_(2)OH)-MMU-O-MMU,M—CH(—OH)—^(+)CH-MMU-O-MMU,and M—CH(—^(+)CH-MMU)-MMU-p-G.

Influence of Annealing Atmosphere on Varistor Property of TiO₂-Nb₂O₅-SrCO₃Ceramics

Varistor ceramics are typical electronic ceramics, which are widely used in circuits of overvoltage protection, high voltage stabilization and high energy surge absorption. TiO2 varistor ceramics has the advantages of low varistor voltage and good dielectric properties, but their low nonlinearity limited the application. The influence of annealing on the varistor properties of TiO2-Nb2O5-SrCO3 ceramics was investigated in this paper. TiO2-Nb2O5-SrCO3 varistor ceramics were prepared by the traditional method of ball grinding-forming-sintering and they were annealed in oxygen and nitrogen, respectively. The nonlinear coefficient α and the breakdown voltage EB of the samples were tested using the varistor dc parameter meter. The microstructure of samples was analyzed by XRD, SEM, STEM-EDAX and SAEDP. The results show that during annealing, Sr2+ ions with a larger radius obtain the kinetic energy and are segregated to grain boundaries, which increases the acceptor density of the grain boundaries and improves α. Annealing in an oxygen atmosphere, the enrichment of oxygen at grain boundaries is also helpful to increase the density of acceptor states and the height of the potential barrier, so as to further increase α. Meanwhile, annealing makes crystalline grains grow properly, which results in even grain size, reduces the porosity and increases the density of grains. So EB tends to reduce. As the doping concentration of Nb2O5 and SrCO3 is 0.15 mol%, respectively, and sintering temperature is 1300°C, TiO2-Nb2O5-SrCO3 varistor ceramics annealed in oxygen for 3 h at 750°C achieved the highest nonlinear coefficient α = 8.9 and the lowest breakdown voltage EB = 19.1 V·mm-1, which annealed in nitrogen achieved α = 8.4, EB = 20.6 V·mm-1, both superior to unannealed samples.

Digital Twin for Integration of Design-Manufacturing-Maintenance:An Overview

Traditional design,manufacturing and maintenance are run and managed independently under their own rules and regulations in an increasingly time-and-cost inefective manner.A unifed platform for efcient and intelligent designmanufacturing-maintenance of mechanical equipment and systems is highly needed in this rapidly digitized world.In this work,the defnition of digital twin and its research progress and associated challenges in the design,manufacturing and maintenance of engineering components and equipment were thoroughly reviewed.It is indicated that digital twin concept and associated technology provide a feasible solution for the integration of design-manufacturingmaintenance as it has behaved in the entire lifecycle of products.For this aim,a framework for information-physical combination,in which a more accurate design,a defect-free manufacturing,a more intelligent maintenance,and a more advanced sensing technology,is prospected.

早期内镜干预与保守治疗应用于急性重症胆源性胰腺炎疗效对比的Meta分析

目的比较早期内镜逆行胰胆管造影术(ERCP)±内镜下十二指肠乳头括约肌切开术(EST)和保守治疗应用于急性重症胆源性胰腺炎(ASBP)的有效性及安全性。方法在Pubmed、Web of Science、Embase、Cochrane Library、中国知网数据库、万方数据库和维普数据库中检索有关比较早期内镜干预和保守方法治疗ASBP的随机对照研究(RCT),并使用RevMan 5.3软件分析数据。结果纳入10篇RCT,共806例患者。Meta分析结果显示,与保守治疗相比,早期内镜干预能降低ASBP总并发症发生率(OR=0.58,95%CI:0.41~0.82,P=0.002)、系统并发症发生率(O^R=0.46,95%CI:0.32~0.67,P=0.000)和胆管炎发生率(OR=0.11,95%CI:0.03~0.42,P=0.001);缩短患者腹痛持续时间(MD=-6.09,95%CI:-7.47~-4.70,P=0.000)和住院时间(MD=-10.15,95%CI:-13.20~-7.09,P=0.000);但两组患者在死亡率、多器官功能障碍综合征(MODS)发生率、呼吸衰竭发生率、局部并发症发生率、假性囊肿发生率和胰腺脓肿/坏死发生率等方面比较,差异均无统计学意义(P>0.05)。结论早期内镜干预治疗ASBP是安全可行的,且具有降低并发症发生率、缓解腹痛及缩短住院时间等优势,有望成为治疗ASBP的首选方法。

Percutaneous drainage in the treatment of intrahepatic pancreatic pseudocyst with Budd-Chiari syndrome:A case report

BACKGROUND Intrahepatic pancreatic pseudocyst(IHPP)is an extremely rare complication of acute pancreatitis,with only a few cases previously described in the literature.To the best of our knowledge,IHPP with Budd-Chiari syndrome(BCS)has not yet been described.CASE SUMMARY A 35-year-old male presented with abdominal pain,vomiting and anorexia,followed by severe swelling of the lower body after 4 d.The morphological assessment(using computed tomography revealed the presence of a huge cyst of 18.28 cm×10.34 cm under the liver capsule accompanied by a large amount of ascites.Percutaneous puncture allowed us to detect a high level of amylase in the collection,confirming the diagnosis of IHPP.The cyst was treated by percu-taneous drainage,producing complete resolution of the cyst.CONCLUSION IHPP can be treated with percutaneous drainage,endoscopic drainage,surgery or even conservative treatment,depending on the specific condition.We recommend percutaneous drainage as the first choice of treatment when IHPP with secondary BCS.

Clear cell renal cell carcinoma located in sinus renalis confused with renal pelvis mass in image

58-year-old Chinese woman presented with a mass in right renal pelvis incidentally detected by ultrasonography(Fig.1A).No positive signs were found by physical examination,and urinalysis was also normal.Enhanced computed tomography(CT)of abdomen displayed a polycystic mass of 2.3 cm2.1 cm1.6 cm in right sinus renalis(Fig.1B and C)with ample blood perfusion in arterial phase(Fig.1B)and less perfusion in venous phase(Fig.1C).

Group-Theoretic Remarks on Goldbach’s Conjecture

The famous strongly binary Goldbach’s conjecture asserts that every even number 2n ≥ 8 can always be expressible as a sum of two distinct odd prime numbers. We use a new approach to dealing with this conjecture. Specifically, we apply the element order prime graphs of alternating groups of degrees 2n and 2n −1 to characterize this conjecture, and present its six group-theoretic versions;and further prove that this conjecture is true for p +1 and p −1 whenever p ≥ 11 is a prime number.

Investigation of Material Properties Based on 3D Graphite Morphology for Compacted Graphite Iron

The strength and thermal conductivity of compacted graphite iron(CGI)are crucial performance indicators in its engineering application.The presence of graphite in CGI significantly influences the two properties.In the previous studies,graphite in CGI was often described using two-dimensional(2D)morphology.In this study,the three-dimensional(3D)size,shape,and distribution of graphite in CGI were analyzed using X-ray tomography.Based on this,a new method is introduced to calculate the 3D vermicularity and compare it with the 2D vermicularity in terms of tensile properties and thermal conductivity.The results demonstrate that vermicular graphite exhibits greater connectivity in 3D observation compared to 2D observation.Therefore,the calculation method of 3D vermicularity is determined by considering the surface area and volume of the connected graphite.Then a linear relationship between 3 and 2D vermicularity has been observed.By comparing the correlation coefficient,it has been found that the 3D vermicularity offers a more accurate method to establish the relationship among graphite morphology,thermal conductivity and tensile property of CGI.

Machine Learning-Based Temperature and Wind Forecasts in the Zhangjiakou Competition Zone during the Beijing 2022 Winter Olympic Games

Weather forecasting for the Zhangjiakou competition zone of the Beijing 2022 Winter Olympic Games is a challenging task due to its complex terrain.Numerical weather prediction models generally perform poorly for cold air pools and winds over complex terrains,due to their low spatiotemporal resolution and limitations in the description of dynamics,thermodynamics,and microphysics in mountainous areas.This study proposes an ensemble-learning model,named ENSL,for surface temperature and wind forecasts at the venues of the Zhangjiakou competition zone,by integrating five individual models—linear regression,random forest,gradient boosting decision tree,support vector machine,and artificial neural network(ANN),with a ridge regression as meta model.The ENSL employs predictors from the high-resolution ECMWF model forecast(ECMWF-HRES) data and topography data,and targets from automatic weather station observations.Four categories of predictors(synoptic-pattern related fields,surface element fields,terrain,and temporal features) are fed into ENSL.The results demonstrate that ENSL achieves better performance and generalization than individual models.The root-mean-square error(RMSE) for the temperature and wind speed predictions is reduced by 48.2% and 28.5%,respectively,relative to ECMWF-HRES.For the gust speed,the performance of ENSL is consistent with ANN(best individual model) in the whole dataset,whereas ENSL outperforms on extreme gust samples(42.7% compared with 38.7% obtained by ECMWF-HRES in terms of RMSE reduction).Sensitivity analysis of predictors in the four categories shows that ENSL fits their feature importance rankings and physical explanations effectively.

Performance in the Fundamentals of Laparoscopic Surgery: Does it reflect global rating scales in the Objective Structured Assessment of Technical Skills in porcine laparoscopic surgery?

Objective:To correlate the utility of the Fundamentals of Laparoscopic Surgery(FLS)manual skills program with the Objective Structured Assessment of Technical Skills(OSATS)global rating scale in evaluating operative performance.Methods:The Asian Urological Surgery Training and Educational Group(AUSTEG)Laparoscopic Upper Tract Surgery Course implemented and validated the FLS program for its usage in laparoscopic surgical training.Delegates’basic laparoscopic skills were assessed using three different training models(peg transfer,precision cutting,and intra-corporeal suturing).They also performed live porcine laparoscopic surgery at the same workshop.Live surgery skills were assessed by blinded faculty using the OSATS rating scale.Results:From March 2016 to March 2019,a total of 81 certified urologists participated in the course,with a median of 5 years of post-residency experience.Although differences in task time did not reach statistical significance,those with more surgical experience were visibly faster at completing the peg transfer and intra-corporeal suturing FLS tasks.However,they took longer to complete the precision cutting task than participants with less experience.Overall OSATS scores correlated weakly with all three FLS tasks(peg transfer time:r=0.331,r^(2)=0.110;precision cutting time:r=0.240,r^(2)=0.058;suturing with intracorporeal knot time:r=0.451,r^(2)=0.203).Conclusion:FLS task parameters did not correlate strongly with OSATS globing rating scale performance.Although FLS task models demonstrated strong validity,it is important to assimilate the inconsistencies when benchmarking technical proficiency against real-life operative competence,as evaluated by FLS and OSATS,respectively.

Early drainage removal in the management of lymphatic leakage after robotic pelvic lymph node dissection

Background:Radical prostatectomy(RP)and radical cystectomy(RC)with concurrent pelvic lymph node dissection(PLND)are considered as the curative surgical treatment options for localized prostate cancer(PC)or muscle-invasive bladder cancer(BC).Regarding lymphatic leakage management after PLND,there is no standard of care,with different therapeutic approaches having been reported with varying success rates.Methods:Seventy patients underwent pelvic lymphadenectomy during robotic RP and RC with postoperative pelvic drainage volume more than 50 mL/day before the removal of drainage tube,were retrospectively evaluated in this study between August 2015 and June 2023.If the pelvic drainage volume on postoperative Day 2 was more than 50 mL/day,a drainage fluid creatinine was routinely tested to rule out urine leakage.We removed the drainage if the patient had no significant abdominal free fluid collection,no abdominal distension or pain,no fever,and no abdominal tenderness.After 1-day observation of the vital signs and abdominal symptoms,the patient was discharged and followed-up in clinic for 2 weeks after surgery.Results:Forty-one cases underwent the early drainage removal even if the pelvic drainage volume was more than 50mL/day.Among these forty-one cases,twenty-five drainage tubes were removed when drainage volume was more than 100 mL/day.All the forty-one cases with pelvic drainage volume greater than 50mL/day were successfully managed with the early drainage removal.No paracentesis or drainage placement was required.No readmission occured during the follow-up period.Conclusion:It is safe to manage the high-volume pelvic lymphatic leakage by early clamping of the drainage tube,ultrasonography assessment of no significant residual fluid in the abdominal and pelvic cavity,and then the early removal of the drainage tube.

The effect of hematoma puncture drainage before decompressive craniectomy on the prognosis of hypertensive intracerebral hemorrhage with cerebral hernia at a high altitude

Purpose:Rapid decompressive craniectomy(DC)was the most effective method for the treatment of hypertensive intracerebral hemorrhage(HICH)with cerebral hernia,but the mortality and disability rate is still high.We suspected that hematoma puncture drainage(PD)+DC may improve the therapeutic effect and thus compared the combined surgery with DC alone.Methods:From December 2013 to July 2019,patients with HICH from Linzhi,Tibet and Honghe,Yunnan Province were retrospectively analyzed.The selection criteria were as follows:(1)altitude≥1500 m;(2)HICH patients with cerebral hernia;(3)Glascow coma scale score of 4-8 and time from onset to admission≤3 h;(4)good liver and kidney function;and(5)complete case data.The included patients were divided into DC group and PD+DC group.The patients were followed up for 6 months.The outcome was assessed by Glasgow outcome scale(GOS)score,Kaplan-Meier survival curve and correlation between time from admission to operation and prognosis.A good outcome was defined as independent(GOS score,4-5)and poor outcome defined as dependent(GOS score,3-1).All data analyses were performed using SPSS 19,and comparison between two groups was conducted using separatet-tests or Chi-square tests.Results:A total of 65 patients was included.The age ranged 34-90 years(mean,63.00±14.04 years).Among them,31 patients had the operation of PD+DC,whereas 34 patients underwent DC.The two groups had no significant difference in the basic characteristics.After 6 months of follow-up,in the PD+DC group there were 8 death,4 vegetative state,4 severe disability(GOS score 1-3,poor outcome 51.6%);8 moderate disability,and 7 good recovery(GOS score 4-5,good outcome 48.4%);while in the DC group the result was 15 death,6 vegetative state,5 severe disability(poor outcome 76.5%),4 moderate disability and 4 good recovery(good outcome 23.5%).The GOS score and good outcome were significantly less in DC group than in PD+DC group(Z=-1.993,p=0.046;χ2=4.38,p=0.043).However,there was no significant difference regarding the survival curve between PD+DC group and DC group.The correlation between the time from admission to operation and GOS at 6 months(r=-0.41,R2=0.002,p=0.829)was not significant in the PD+DC group,but significant in the DC group(r=-0.357,R2=0.128,p=0.038).Conclusion:PD+DC treatment can improve the good outcomes better than DC treatment for HICH with cerebral hernia at a high altitude.

Transcription Factors:Potential Cell Death Markers in Parkinson's Disease

Parkinson＇s disease （PD） is a neurodegenerative disease with a long preclinical phase. The continuous loss of dopaminergic （DA） neurons is one of the pathogenic hallmarks of PD. Diagnosis largely depends on clinical observation, but motor dysfunctions do not emerge until 70%-80% of the nigrostriatal nerve terminals have been destroyed. Therefore, a biomarker that indicates the degeneration of DA neurons is urgently needed. Transcrip- tion factors are sequence-specific DNA-binding proteins that regulate RNA synthesis from a DNA template. The precise control of gene expression plays a critical role in the development, maintenance, and survival of cells, including DA neurons. Deficiency of certain transcription factors has been associated with DA neuron loss and PD. In this review, we focus on some transcription factors and discuss their structure, function, mechanisms of neuropro- tection, and their potential for use as biomarkers indicating the degeneration of DA neurons.

Integration of multiscale entropy and BASED scale of electroencephalography after adrenocorticotropic hormone therapy predict relapse of infantile spasms

Background Even though adrenocorticotropic hormone(ACTH)demonstrated powerful efficacy in the initially successful treatment of infantile spasms(IS),nearly half of patients have experienced a relapse.We sought to investigate whether features of electroencephalogram(EEG)predict relapse in those IS patients without structural brain abnormalities.Methods We retrospectively reviewed data from children with IS who achieved initial response after ACTH treatment,along with EEG recorded within the last two days of treatment.The recurrence of epileptic spasms following treatment was tracked for 12 months.Subjects were categorized as either non-relapse or relapse groups.General clinical and EEG recordings were collected,burden of amplitudes and epileptiform discharges(BASED)score and multiscale entropy(MSE)were carefully explored for cross-group comparisons.Results Forty-one patients were enrolled in the study,of which 26(63.4%)experienced a relapse.The BASED score was significantly higher in the relapse group.MSE in the non-relapse group was significantly lower than the relapse group in theγband but higher in the lower frequency range(δ,θ,α).Sensitivity and specificity were 85.71%and 92.31%,respectively,when combining MSE in theδ/γfrequency of the occipital region,plus BASED score were used to distinguish relapse from non-relapse groups.Conclusions BASED score and MSE of EEG after ACTH treatment could be used to predict relapse for IS patients without brain structural abnormalities.Patients with BASED score≥3,MSE increased in higher frequency,and decreased in lower frequency had a high risk of relapse.

Experimental and finite element analysis studies of a reduction-force reducing traction method for pelvic fracture surgeries

Pelvic fracture is among the most complicated fractures in traumatic orthopedics,with high mortality and morbidity rates.The main difficulty associated with the reduction surgery is significant muscle resistance.It then becomes necessary to decrease the reduction force against this strong muscle resistance,for improving surgical safety.Here,we propose a novel traction method for decreasing the reduction force during pelvic reduction,and investigate the performance of the elastic traction method on decreasing the reduction force using experimental tests and simulation-based analyses.From the experimental results,the reduction force decreased by 59.2%when 10 kg of elastic traction was applied.We also establish a musculoskeletal model of the pelvic fracture reduction,for analyzing the muscle resistance and the optimal traction force applied in reduction surgeries.The elastic traction method can counteract the muscle resistance increase in the non-traction direction owing to its flexibility.We conclude that the optimal traction force applied should be in the 10–15 kg range,and recommend adopting a dynamic traction strategy rather than continuous traction in clinical settings.Elastic traction is very promising for various surgeries that require traction,including pelvic reduction.It significantly reduces force,which can significantly reduce the physical exertion of the operating surgeon,the possibility of additional injuries to the operated patient,and promotes robot-assisted reduction surgeries.

Death after discharge:prognostic model of 1-year mortality in traumatic brain injury patients undergoing decompressive craniectomy

Background:Despite advances in decompressive craniectomy(DC)for the treatment of traumatic brain injury(TBI),these patients are at risk of having a poor long-term prognosis.The aim of this study was to predict 1-year mortality in TBI patients undergoing DC using logistic regression and random tree models.Methods:This was a retrospective analysis of TBI patients undergoing DC from January 1,2015,to April 25,2019.Patient demographic characteristics,biochemical tests,and intraoperative factors were collected.One-year mortality prognostic models were developed using multivariate logistic regression and random tree algorithms.The overall accuracy,sensitivity,specificity,and area under the receiver operating characteristic curves(AUCs)were used to evaluate model performance.Results:Of the 230 patients,70(30.4%)died within 1 year.Older age(OR,1.066;95%CI,1.045-1.087;P<0.001),higher Glasgow Coma Score(GCS)(OR,0.737;95%CI,0.660-0.824;P<0.001),higherD-dimer(OR,1.005;95%CI,1.001-1.009;P=0.015),coagulopathy(OR,2.965;95%CI,1.808-4.864;P<0.001),hypotension(OR,3.862;95%CI,2.176-6.855;P<0.001),and completely effaced basal cisterns(OR,3.766;95%CI,2.255-6.290;P<0.001)were independent predictors of 1-year mortality.Random forest demonstrated better performance for 1-year mortality prediction,which achieved an overall accuracy of 0.810,sensitivity of 0.833,specificity of 0.800,and AUC of 0.830 on the testing data compared to the logistic regression model.Conclusions:The random forest model showed relatively good predictive performance for 1-year mortality in TBI patients undergoing DC.Further external tests are required to verify our prognostic model.

“The Monkey King Meets the Spiderman”:Narrative Inquiry into Chinese Students’Academic Socialization Experiences in a U.S.University

This narrative study explores four Chinese students’academic socialization experiences in one research-intensive public university in the US.By drawing upon Wenger’s(1998)communities of practice and Gee’s(2000)theorizing on identity as the synthesized theoretical framework,this research uncovers four Chinese students’academic socialization stories nestled in the shifting cross-cultural landscape.Meanwhile,this study reveals that the Chinese students’academic socialization intersects a matrix of factors,which can be categorized into“personal landscape”and“professional landscape.”Last,this narrative case study concluded that the Chinese students’academic socialization involves the continuous negotiations of their multiple identities embedded in the cross-cultural contexts.