Prognostic Value of Semi-Quantitative 18F-FDG PET/CT Parameters in Hodgkin’s Lymphoma

Objective:To assess the prognostic value of maximum standardized uptake value(SUVmax),metabolic tumor volume(MTV),and total lesion glycolysis(TLG)determined by 18F-fluorodeoxyglucose positron emission tomography-computed tomography(18F-FDG PET/CT)imaging in Hodgkin’s lymphoma patients.Methods:A total of 148 Hodgkin’s lymphoma patients diagnosed with lymph node biopsy from October 2014 to October 2015 were retrospectively analyzed followed by categorizing into good(125 cases)and poor(23 cases)prognosis groups.The chi-squared test was used to analyze the clinicopathological characteristics of Hodgkin’s lymphoma patients with the semi-quantitative 18F-FDG PET/CT parameters;the Spearman method was used to analyze the correlation between the semi-quantitative parameters and clinicopathological features of Hodgkin’s lymphoma;receiver operating characteristic curve was used to analyze the predictive value of the semi-quantitative parameters for poor prognosis of Hodgkin’s lymphoma patients.Results:Mean SUVmax,MTV,and TLG of the 148 cases of Hodgkin’s lymphoma were 7.26±2.38,12.46±3.14 cm3,and 76.83±18.56 g,respectively.Significant variations in the Ann Arbor stage and clinical classification were observed with different levels of semi-quantitative parameters(P<0.05).The semi-quantitative parameters were not correlated with age and gender(P>0.05)but positively correlated with Ann Arbor stage and clinical classification(P<0.05).These parameters in the poor prognosis group were higher than those in the good prognosis group(P<0.05).The area under the curve(AUC)of SUVmax,MTV,and TLG in predicting the poor prognosis group was 0.881,0.875,and 0.838,with cut-off values of 7.264,12.898 cm3,and 74.580g,as well as specificity of 88.8%,84.0%,and 78.4%,and sensitivity of 87.0%,87.0%,and 78.3%,respectively;the AUC of the combined prediction was 0.986,with a specificity of 97.6%and sensitivity of 86.3%.Conclusion:The semi-quantitative 18F-FDG PET/CT parameters provide valuable insights for Hodgkin’s lymphoma prognosis assessment.

Lumbopelvic Fixation and Sacral Decompression for U-shaped Sacral Fractures： Surgical Management and Early Outcome

U-shaped sacral fractures are rare and often difficult to diagnose primarily due to the difficulty in obtaining adequate imaging and the severe associated injuries. These fractures are highly unstable and frequently cause neurological deficits. The majority of surgeons have limited experience in management of U-shaped sacral fractures. No standard treatment protocol for U-shaped sacral fractures has been available till now. This study aimed to examine the management of U-shaped sacral fractures and the early outcomes. Clinical data of 15 consecutive patients with U-shaped sacral fracture who were admitted to our trauma center between 2009 and 2014 were retrospectively analyzed. Demographics, fracture classification, mechanism of injury and operative treatment and deformity angle were assessed. All the patients were treated with lumbopelvic fixation or （and） sacral decompression. EQ-5d score was applied to evaluate the patients＇ quality of life. Of the 15 consecutive patients with U-shaped sacral fracture, the mean age was 28.8 years （range： 15-55 years） at the time of injury. There were 6 females and 9 males. The mean follow- up time was 22.7 months （range： 9-47 months） and mean full weight-bearing time was 9.9 weeks （range： 8-14 weeks）. Ten patients received lumbopelvic fixation and sacral decompression, one lombosacral fixation, and 4 merely sacral decompression due to delayed diagnosis or surgery. The post-operation deformity angle （mean 27.87°, and range： 8°-90°） of the sacrum was smaller than that pre-operation （mean 35.67; range： 15-90） with no significance difference noted. At the latest follow-up, all patients obtained neurological recovery with different extents. Visual analogue score （VAS） was reduced from preoperative 7.07 （range： 5-9） to postoperetive 1.93 （range： 1-3）. All patients could walk without any aid after treatment. Eight patients were able to care for themselves and undertook some daily activities. Five patients had returned to work full time. In conclusion, lumbopelvic fixation is an effective method for stabilization of U-shaped sacral fractures with fewer complications developed. Effective reduction and firm fixation are the prerequisite of early mobilization and neurological recovery. Sacral decompression effectively promotes neurological recovery even in patients with old U-shaped sacral fractures.

Interactions between water-land resources and oasis urban development at the northern slopes of the Tianshan Mountains,Xinjiang,China

Urban development in arid and semi-arid regions is largely constrained by fragile physical environ- ments. The characteristics of an urban settlement are different from those in other regions of China. This paper analyses the coupling characteristics and spatio-temporal variations for oasis urban development and water-land resources at the northern slopes of the Tianshan Mountains by principal component analysis and a coupling degree model. The result shows that the degree and change in regional use of water and land resources are different among the studied cities/counties during their development. The built-up areas of these cities/counties have changed little with increasing populations and urbanization levels, which well reflects that the urban development in arid and semi-arid regions is limited by oasis areas. Per capita amount of water supplied, however, presented a trend of slowed growth with increasing levels of urbanization. Water consumption gradually increased with urban development and the improvement of people＇s living standards, accompanied by enhanced water use efficiency. The level of urbanization can be assessed through the coupling degree between oasis urban development and the use of water and land resources. A high coupling degree represents a high level of comprehensive urban devel- opment and use of water-land resources. Alternatively, a low coupling degree denotes a low level of urban devel- opment and water-land resource use.

微创治疗Schatzker Ⅰ~Ⅲ型胫骨平台骨折的疗效观察

目的分析微创治疗SchatzkerⅠ~Ⅲ型胫骨平台骨折的疗效。方法选取2014年1月-2018年8月海警总队医院收治的胫骨平台骨折患者84例(SchatzkerⅠ~Ⅲ型),按随机数字表法分为观察组和对照组,每组42例。对照组采用手术切开复位钢板内固定;观察组采用微创经皮钢板固定。比较两组手术相关指标、关节功能恢复及并发症发生情况等。结果观察组手术时间、手术切口长度、住院时间、术后开始负重时间及骨折愈合时间短于对照组(P<0.05)。观察组手术前后膝关节活动度、美国膝关节协会评分及骨折复位评分的差值高于对照组(P<0.05)。观察组术后并发症发生率低于对照组(P<0.05)。结论采用微创经皮钢板固定术治疗SchatzkerⅠ~Ⅲ型胫骨平台骨折的患者,临床效果较好,创伤小、并发症少,术后恢复较快,具有良好的临床应用价值。

Psychometric properties of the Chinese version of the Infertility Self-Efficacy Scale

Objective:To translate the English version of Infertility Self-Efficacy Scale into Chinese and to validate the psychometric properties of the Chinese version of the Infertility Self-Efficacy Scale(CISE).Method(s):Participants were recruited from the Gynecology Department of two city hospitals.Five main processes were involved in the formation of CISE[1]:scale translation based on expert consultation[2];pre-test questionnaire development with infertile women's feedback(N=20)[3];factor structure assessed by exploratory and confirmatory factor analysis(N=177)[4];assessment of reliability by internal consistency(N=177)and test-retest reliability(N=21);and[5]assessment of convergent validity with Self-rating Anxiety Scale,Self-rating Depression Scale,and Simplified Coping Style Questionnaire(N=177).Results:This study established a 16-item CISE.Factor analyses confirmed a onecomponent solution,which explained 54.59% of total variances and showed an acceptable model fit.Cronbach's a and test-retest correlation coefficients for the scale were 0.94 and 0.84,respectively.The CISE score was significantly correlated with anxiety(r=0.47),depression(r=0.60),positive coping style(r=0.37),and certain negative coping style items.Conclusion:This 16-item CISE is a reliable and valid measure to evaluate perceived selfefficacy among a sample of Chinese women who underwent infertility treatment.

The comparisons on total RNA from different source-original neurons applied in LMPC

Objective To compare the quality and quantity of total RNA from different source-original neurons applied in LMPC technique. Methods （ 1 ） Aglient 2100 bioanalyzer and RT-PCR were used to check the concentration and fragmentation of total RNA from unfixed, temporal fixed and fixed 12 h hypothalamus sections; （2）Different neurons of PVN and SON were collected by LMPC, CRH, TRH, AVP, OT mRNA level were measured by RT-PCR; （3）Labeled neurons by injecting CTB into stomach and non-labeled neurons in DMV collected by LMPC were checked for house keeping genes by RT-PCR. Results （ 1 ） Unfixed section had higher concentration and better quality of total RNA compared with fixed sections applied in LMPC ; relative short amplicons such as GAPDH, NSE, MCH and MCAR were successfully obtained from fixed and unfixed and long amplicon of GR can only be obtained from unfixed material; （2） In magnocellular PVN and SON the expressions of AVP and OT were more special than those in the parvocellular PVN. Oppositely, the expressions of CRH, TRH in the parvocellular were more special than the other two ; （3） The expressions of house keeping genes had no significant difference between labeled and non-labeled DMV neurons. Conclusion The quality and quantity of total RNA from unfixed brain tissues were better than fixed tissues applied in LMPC and the CTB tracer which may differentiate neurons had no significant effect on physiology of the neurons applied in LMPC. The results showed that the LMPC technique is suitable for the qualitative and quantitative study on individual neurons at mRNA level.

Simple cholecystectomy is an adequate treatment for grade I T1bN0M0 gallbladder carcinoma:Evidence from 528 patients

BACKGROUND T1b gallbladder carcinoma(GBC)is defined as a tumor that invades the perimuscular connective tissue without extension beyond the serosa or into the liver.However,controversy still exists over whether patients with T1b GBC should undergo cholecystectomy alone or radical GBC resection.AIM To explore the optimal surgical approach in patients with T1b gallbladder cancer of different pathological grades.METHODS Patients with T1bN0M0 GBC who underwent surgical treatment between 2000 and 2017 were included in the Surveillance,Epidemiology,and End Results database.The Kaplan-Meier method and log-rank test were used to analyze the overall survival(OS)and disease-specific survival(DSS)of patients with T1b GBC of different pathological grades.Cox regression analysis was used to identify independent predictors of mortality and explore the selection of surgical methods in patients with T1b GBC of different pathological grades and their relationship with prognosis.RESULTS Of the 528 patients diagnosed with T1bN0M0 GBC,346 underwent simple cholecystectomy(SC)(65.5%),131 underwent SC with lymph node resection(SC+LN)(24.8%),and 51 underwent radical cholecystectomy(RC)(9.7%).Without considering the pathological grade,both the OS(P<0.001)and DSS(P=0.003)of T1b GBC patients who underwent SC(10-year OS:27.8%,10-year DSS:55.1%)alone were significantly lower than those of patients who underwent SC+LN(10-year OS:35.5%,10-year DSS:66.3%)or RC(10-year OS:50.3%,10-year DSS:75.9%).Analysis of T1b GBC according to pathological classification revealed no significant difference in OS and DSS between different types of procedures in patients with grade Ⅰ T1b GBC.In patients with grade Ⅱ T1b GBC,obvious survival improvement was observed in the OS(P=0.002)and DSS(P=0.039)of those who underwent SC+LN(10-year OS:34.6%,10-year DSS:61.3%)or RC(10-year OS:50.5%,10-year DSS:78.8%)compared with those who received SC(10-year OS:28.1%,10-year DSS:58.3%).Among patients with grade Ⅲ or Ⅳ T1b GBC,SC+LN(10-year OS:48.5%,10-year DSS:72.2%),and RC(10-year OS:80%,10-year DSS:80%)benefited OS(P=0.005)and DSS(P=0.009)far more than SC(10-year OS:20.1%,10-year DSS:38.1%)alone.CONCLUSION Simple cholecystectomy may be an adequate treatment for grade Ⅰ T1b GBC,whereas more extensive surgery is optimal for grades Ⅱ-Ⅳ T1b GBC.

TLR4 Knockout Attenuates BDL-induced Liver Cholestatic Injury through Amino Acid and Choline Metabolic Pathways

The exact mechanism by which knockout of Toll-like receptor 4(TLR4)attenuates the liver injury remains unclear.The present study aimed to examine the role of TLR4 in the pathogenesis of bile duct ligation(BDL)-induced liver cholestatic injury and the underlying mechanism.Wild type(WT)mice and TLR4 knockout(TLR4-KO)mice were used for the establishment of the BDL model.Metabolomics were applied to analyze the changes of small molecular metabolites in the serum and liver of the two groups.The serum biochemical indexes and the HE staining results of liver tissue showed that liver damage was significantly reduced in TLR4-KO mice after BDL when compared with that in WT mice.The metabolite analysis results showed that TLR4 KO could maintain the metabolisms of amino acids-and choline-related metabolites.After BDL,the amino acids-and choline-related metabolites,especially choline and 3-hydroxybutyrate,were significantly increased in WT mice(both in serum and liver),but these metabolites in the liver of TLR4-KO mice after BLD were not significant different from those before BLD.In conclusion,TLR4 KO could attenuate BDL-induced liver cholestatic injury through regulating amino acid and choline metabolic pathways.

Clinical effect of terbutaline injection aerosol inhalation combined with conventional drug therapy for acute attack of bronchial asthma in children

Objective: To study the clinical effect of terbutaline injection aerosol inhalation combined with conventional drug therapy for acute attack of bronchial asthma in children. Methods:Children with acute attack of bronchial asthma who were treated in Wusheng Hospital of Traditional Chinese Medicine and Qiandongnan Prefecture People's Hospital between January 2014 and July 2017 were selected as the study cases for prospective study and randomly divided into the experimental group who received terbutaline + budesonide aerosol inhalation and the control group who received budesonide aerosol inhalation. The expression levels of immune cell transcription factors in peripheral blood as well as the contents of adhesion factors, chemokines, proteases and their inhibitory molecules in serum were determined before treatment and 3 days after treatment. Results: Foxp3 and T-bet expression in peripheral blood as well as TIMP1 and TIMP2 contents in serum of both groups after treatment were higher than those before treatment whereas RORγt and GATA-3 expression in peripheral blood as well as TARC, Eotaxin, ICAM-1, VCAM-1, L-selectin, ADAM8, NE and MMP9 contents in serum were lower than those before treatment, and Foxp3 and T-bet expression in peripheral blood as well as TIMP1 and TIMP2 contents in serum of experimental group after treatment were higher than those of control group whereas RORγt and GATA-3 expression in peripheral blood as well as TARC, Eotaxin, ICAM-1, VCAM-1, L-selectin, ADAM8, NE and MMP9 contents in serum were lower than those of control group. Conclusion: Terbutaline injection aerosol inhalation combined with conventional drug therapy can effectively regulate the immune response and inflammatory response and inhibit the airway remodeling mediated by protease in children with acute attack of bronchial asthma.

改良McBride手术联合跖骨双截骨术治疗青少年踇外翻的生物力学分析

目的对改良McBride手术联合跖骨双截骨术治疗青少年踇外翻的生物力学进行分析。方法选取2015年4月-2018年8月在海警总队医院治疗的青少年踇外翻患者45例,按随机数字表法分为对照组(22例)和实验组(23例),分别采用改良McBride手术和改良McBride手术联合跖骨双截骨术治疗。术前和术后随访1年行足部X射线检查,测量外翻角(IMA),第1、2跖骨间角(HVA)和第4、5跖骨间角(IM 4-5),采用AOFAS功能评分评估前足功能,采用视觉模拟评分(VAS)评估疼痛。采用足底压力测试系统测量患者足底压力分布。结果①术后随访1年,实验组患者HVA、IMA、IM 4-5和VAS评分均低于对照组,AOFAS评分高于对照组(P<0.05)。②术后随访1年,实验组患者双足第1跖骨平均压力峰值低于对照组(P<0.05);而其他区域的平均压力峰值比较,差异无统计学意义(P>0.05)。③术后随访1年,实验组患者双足第2~5趾骨、第1跖骨、足跟内侧和足跟外侧的平均冲量值低于对照组(P<0.05);而其他区域的平均冲量值比较,差异无统计学意义(P>0.05)。结论改良McBride手术联合跖骨双截骨术可能通过降低第1跖骨区压力和负重,改善踇外翻畸形,具有良好的临床应用前景。

Characterization of β-lactamase from Escherichia coli with drug-resistance to ceftazidine

The antimicrobial susceptibility testing was performed with Kirby-Bauer disc diffusion and agar diffusion methods, and the crude β-lactamase was extracted by sonication with its isoelectric point（pI） determined with isoelectric focusing, and purified by two steps of chromatography. The genome DNA fragments of bacterial strains were amplified with PCR and subjected to sequencing. The kinetic parameters for β-lactamase were detected by spectrophoto metric method. It was found that the bacterial strains isolated from clinical specimens were resistant to penicillin, ceftazidine, cefotaxime and azitreonam, but sensitive to imipenem and cefoxitin, in which two resistant strains to ceftazidine were found to produce a single extended spectrum β-lactamase（ESBL） with pI value of 8.7. Results of cloning and sequencing of the β-lactamase encoding gene showed that this gene was similar to blactx-m-1 with 6 point mutations including 3 silent mutations. The amino acid sequence derived from the nucleic acid data indicated that this enzyme was distinct from β-lactamse CTX-M-1 by 3 amino acids, i.e. Val-80→Ala, Asp-117→Asn and Ser-143→Ala（CTX-M-1V）. Molecular weight of this enzyme was 29 kDa. Kinetic analysis of the partially purified β-lactamase confirmed that this enzyme was able to hydrolyze cefotaxime and aztreonam, but not to imipenem. In addition, the β-lactamase was well inhibited by sulbactam（IC50 94 nM） and tazobactam（IC50 5 nM）. It is concluded that CTX-M-1V is a CTX-M-type extended spectrum β-lactamase.

Universal production of functionalized 2D nanomaterials via integrating glucose-assisted mechanochemical exfoliation and cosolvent-intensified sonication exfoliation

Two-dimensional(2D)nanomaterials have aroused immense attention in extensive applications due to their intriguing physical and chemical properties.However,there is a formidable challenge to prepare few-layered and functionalized 2D nanomaterials in an effective and universal way.Herein,we developed an integrated strategy of glucose-assisted mechanochemical exfoliation and cosolvent-intensified sonication exfoliation to effectively exfoliate and functionalize 2D materials.Taking exfoliation of boron nitride(BN)as an example,the production yield and functionalization ratio of BN nanosheets(BNNSs)reached 47.5%and 25.8 wt.%,188%and 16%higher than that of BNNSs without sonication exfoliation,respectively.The introduction of glucose not only augmented the friction force between adjacent BN layers to promote the efficiency of ball-milling-driven exfoliation supported by density functional theory calculation,but also reacted with active edges of BNNSs for functionalization.Afterwards,cosolventintensified sonication exfoliation strongly stabilized exfoliated BNNSs,obviously boosting the exfoliation yield.This proposed method is universal for preparing various 2D nanomaterials like molybdenum disulfide,tungsten disulfide,and graphene nanosheets.The thin plate structure and high functionalization ratio enabled the release of property superiorities of 2D nanomaterials.Our work offers a promising prototype to realize mass production of functionalized 2D nanomaterials.

Robotic hepatectomy: challenge and progression

As of June 30,2022,approximately 7,135 da Vinci Surgical Robot units(da Vinci Intuitive Surgical Inc,Sunnyvale CA,USA),the most advanced technology in minimally invasive surgery(MIS),had been installed worldwide,with approximately 70 countries using the da Vinci Surgical Robot and over 10 million surgeries performed with the da Vinci Surgical Robot.

动态保压注塑成型的动态数值仿真与实验结果分析

为实现动态保压注塑成型(OPIM)的智能精密制造,以哑铃型拉伸试样构建几何模型,以Dynamic feed系统还原保压阶段中复杂的动态流动场,运用Moldflow模拟仿真出OPIM全过程.通过与传统注塑成型(CIM)的对比研究,探究了OPIM在保压阶段的熔体流动情况、皮芯结构上熔体温度以及剪切速率分布与大小的变化.通过二维广角X射线衍射(2D-WAXD)、扫描电子显微镜(SEM)以及显微镜实验对模拟结果进行验证.结果表明,在OPIM过程中,熔体在较低黏度下可反复通过型腔,在型腔厚度方向上产生温度梯度,形成强剪切场,进而诱导分子链伸直,形成串晶结构,从而提高了OPIM制品性能,模拟与实验结果一致.

血清musclin水平与冠状动脉病变的关系

目的:比较冠心病患者和对照组血清musclin水平,探讨musclin与冠心病的相关性。方法:纳入经冠状动脉造影确诊为冠心病的患者69例(冠心病组)和冠状动脉造影正常组96例(对照组),用ELISA方法测定其血清musclin水平。根据患者临床表现、心肌酶水平和心电图将冠心病组患者分为稳定型心绞痛组(30例)和急性冠脉综合征组(39例),同时根据冠状动脉病变支数将其分为单支组(27例)、双支组(22例)和多支组(20例)。比较各组血清musclin水平。结果:(1)与对照组比较,冠心病组血清musclin水平明显降低,差异有统计学意义[(119.64±87.57)pg/ml∶(82.03±56.21)pg/ml,P<0.01];(2)急性冠脉综合征组血清musclin水平较稳定型心绞痛组降低,差异有统计学意义[(72.69±28.65)pg/ml∶(94.17±77.86)pg/ml,P<0.05];(3)单支组[(69.99±22.28)pg/ml]、双支组[(82.52±60.00)pg/ml]和多支组[(97.73±78.64)pg/ml]血清musclin水平依次升高,但各组间差异无统计学意义。结论:冠心病患者血清musclin水平明显降低,且降低程度与冠心病严重程度呈负相关。

Decomposition of energy-related carbon emissions in Xinjiang and relative mitigation policy recommendations

Regional carbon emissions research is necessary and helpful for China in realizing reduction targets. The LMDI I （Logarithmic Mean Divisia Index I） technique based on an extended Kaya identity was conducted to uncover the main five driving forces for energy-related carbon emissions in Xinjiang, an important energy base in China. Decomposition results show that the affluence effect and the population effect are the two most important contributors to increased carbon emissions. The energy intensity effect had a positive influence on carbon emissions during the pre-reform period, and then became the dominant factor in curbing carbon emissions after 1978. The renewable energy penetration effect and the emission coefficient effect showed important negative but relatively minor effects on carbon emissions. Based on the local realities, a comprehensive suite of mitigation policies are raised by considering all of these influencing factors. Mitigation policies will need to significantly reduce energy intensity and pay more attention to the regional economic development path. Fossil fuel substitution should be considered seriously. Renewable energy should be increased in the energy mix. All of these policy recommendations, if implemented by the central and local government, should make great contributions to energy saving and emission reduction in Xinjiang.

The classification and assessment of vulnerability of man-land system of oasis city in arid area

Oasis city system is the center of the man-land relationship in arid area and it is the most influential spatial and temporal multiple dynamic system. Oasis city system is not only the largest area where artificial disturbances occur at a regional scale but also the most concentrated area of human activity in arid area. In this study, we developed an applicable and convenient method to assess vulnerability of man-land system of oasis cities with vulnerability indicator system, respectively evaluating the sensitivity, adaptability and vulnerability of the eco- environment system, the economic system and the social system. The results showed that the sensitivity and vulnerability of oasis cities in Xinjiang, China have significant differences while their adaptability does little. In order to find the inherent differences in the vulnerability of oasis cities, triangle methodology has been adopted to divide Xinjiang oasis cities into five types. Some adaptive developing policies specific for individual cities are also proposed based on their vulnerability type and constrain- ing factors.

可旋转稳定型假体与单纯铰链型假体应用于胫骨近端恶性骨肿瘤治疗中的短期随访研究

目的探讨可旋转稳定型假体与单纯铰链型假体治疗胫骨近端恶性骨肿瘤的效果差异,为实际使用提供参考价值。方法回顾性分析2015年6月—2019年6月在我院应用两种不同类型假体治疗的60例胫骨近端恶性肿瘤患者的临床资料,分为对照组和研究组。30例患者接受单纯铰链型假体置换为对照组,30例患者接受可旋转稳定型假体置换为研究组,比较组间差异。结果治疗前,两组膝关节功能评分无显著差异,P>0.05;治疗后,研究组评分为(23.27±2.12)分、对照组为(19.13±4.52)分,均显著高于治疗前,t值分别为10.811、3.713,差异显著(P<0.05);其中,研究组治疗后评分显著高于对照组,t值为4.542,差异显著(P<0.05)。研究组社会活动得分为(27.25±3.16)分、躯体活动得分为(41.17±2.59)分、情感得分为(20.18±2.13)分、疼痛得分为(30.26±4.15)分、睡眠得分为(25.18±2.19)分、精力得分为(33.25±3.47)分,均低于对照组,t值分别为4.609、13.565、7.724、6.629、19.632、5.539,差异具有统计学意义(P<0.05)。研究组患者中,仅出现3例肿瘤复发、1例关节腔内积血,发生率为13.33%,明显低于对照组的40%,χ^2为4.176,差异具有统计学意义(P<0.05)。结论可旋转稳定型假体可有效提升患者膝关节功能恢复,改善术后生活质量、减少并发症发生,值得临床推广应用。但值得注意的是,由于存在一定几率复发可能性,在选择保肢手术时应严格遵守适应证。

Better Choice:Linear Long Chains Rather than Branched Ones to Improve Mechanical Performance of Polyethylene through Generating Shish-Kebabs

We utilized two structurally different long chains(linear and branched ultra-high molecular weight polyethylene)to reveal the dependence of flow-induced crystallization on long chain architecture,and prepared two bi-disperse systems of 98 wt%short chain and 2 wt%long chain.A flow field was applied to the bi-disperse polyethylene melt by a modified injection-molding machine,known as oscillation shear injection molding(OSIM).For the first time,the structural influence of long chains on flow-induced shish-kebab formation was systematically investigated.For the intermediate layer of OSIM samples,the branched long chains were better than the linear long chains at inducing shish-kebab formation,agreeing with the reported literatures,because the branches can maintain their oriented conformations longer.But unexpectedly,the reverse is the case for the core layer of OSIM samples,where the shear flow was much weaker than the intermediate layer.To understand the unexpected phenomenon,the lifetime of shishes induced by different long chains was compared.Result demonstrated that the linear-induced shishes possessed higher thermal stability than the branched-induced ones so that the linear-induced shishes could survive in the core layer of OSIM samples.Additionally,unlike other methods for flow-induced crystallization,OSIM could create samples for measuring mechanical properties,and thus offer the chance to reveal the relationship between structure and performance.The mechanical results demonstrated that both long chains remarkably enhanced the mechanical properties because of the significant promoting effect of long chains and intense flow fields on shish-kebab formation.However,the linear long chains induced more stable and flawless shishes with higher tensile strength and modulus(80.4 and 1613.5 Mpa,respectively)than the branched ones(74.4 and 1489.3 Mpa).Our research not only helps elucidate the mechanism of shish-kebab formation but also provides a better choice to reinforce polymers by adding long chains with suitable structure.

Insight into the Excellent Tribological Performance of Highly Oriented Poly(phenylene sulfide)

Achieving low friction and wear of poly(phenylene sulfide)(PPS) without using fillers or blending is a challenging task, but one of considerable practical importance. Here we describe how neat PPS with high tribological performance is achieved by manipulating processing parameters(pressure, flow and temperature). The key to achieving high tribological performance is comparatively high molecular chain orientation, realized in neat PPS, at high shear rates and low pressure. The friction coefficient and wear rate are as low as ~0.3 and~10^(-6) mm^(3)·N^(-1)·m^(-1), respectively, which break the record for neat PPS. These values are even better than those for PPS-based blends and comparable to PPS composites. Further studies show, for the first time, that wear rate decreases exponentially with increasing molecular chain orientation, prompting us to revise the classical Archard's law by including the effect of molecular chain orientation. These findings open the possibility of using neat PPS in highly demanding tribological applications.