Numerical Simulation Study of Support Pressure around the Fully Mechanized Caving Face

During the fully mechanized caving face re-recovery process, due to the influence of mining and the redistribution of surrounding rock stress, a higher advanced support pressure and lateral support pressure will be formed around the working surface. The superimposed advanced and lateral support pressure will have a greater impact on the advanced support of the working surface roadway. In order to improve the stability of the surrounding rock, the three Hebi mines were used as the subject of the study. At the same time, Universal Distinct Element Code software was used to study the pressure distribution pattern of over-support at the working face. Finally, the results of the study are used as theoretical support and reference for the support scheme.

Numerical Simulation Study of Support Pressure around the Fully Mechanized Caving Face

During the fully mechanized caving face re-recovery process, due to the influence of mining and the redistribution of surrounding rock stress, a higher advanced support pressure and lateral support pressure will be formed around the working surface. The superimposed advanced and lateral support pressure will have a greater impact on the advanced support of the working surface roadway. In order to improve the stability of the surrounding rock, the three Hebi mines were used as the subject of the study. At the same time, Universal Distinct Element Code software was used to study the pressure distribution pattern of over-support at the working face. Finally, the results of the study are used as theoretical support and reference for the support scheme.

磷石膏资源化利用研究进展及未来趋势的可视化分析

为分析磷石膏资源化利用现状、热点及未来发展趋势,以中国知网(CNKI)数据库和Web of Science核心数据库为数据源,检索2002—2022年有关磷石膏的文献;利用CiteSpace可视化软件,从发文量、作者、发文机构、关键词绘制知识图谱等进行探析。结果表明,中英文发文量一直处于稳定发展期;作者合作强度不紧密;当前磷石膏研究集中在预处理、综合应用、重金属元素的固化和放射性元素的防护;未来该行业的发展方向是促进与其他领域的合作,拓宽应用途径。

复杂双面边坡整体稳定性分析

实际工程中边坡常呈现出复杂的几何结构,利用有限元强度折减法讨论了3种边界条件下凹凸坡结构和不同坡度组合情况双面边坡的安全系数和破坏特性,并与单面平直边坡进行对比分析。研究发现:在本次计算条件下,双面边坡垂直放坡时,单面平直边坡的安全系数大于凸坡;对于凸坡其他情况,全约束边界条件下安全系数最大,与平直边坡相比提高了约3%。所有形式的凹坡的安全系数均大于平直边坡,其中,全曲面凹坡在全约束边界条件下安全系数提高了近10%,约为其余形式凹坡的2倍。当双面边坡横纵坡度不等时,边坡沿危险坡面产生滑移,决定边坡整体稳定性的因素为较陡的坡度;坡度相等时,边界条件对双面边坡破坏模式的影响较为明显,不同边界条件将导致边坡不同的破坏形态,在半约束条件下,双面边坡只沿法向约束一侧产生滑移破坏,而另外两种约束条件下,其破坏区域均为对称形状。

粉煤灰加气混凝土的研究概述

作为煤炭燃烧后产生的工业废渣,粉煤灰的大量堆积会造成环境污染。近年来,粉煤灰被广泛应用于加气混凝土的生产中。这样的应用生产方式不仅可以保护环境,而且可以降低成本。主要从粉煤灰加气混凝土的优点,生产工艺、配合比、存在的问题几方面进行分析总结。

Laparoscopic vs open extended right hemicolectomy for colon cancer

AIM:To evaluate the feasibility,safety,and oncologic outcomes of laparoscopic extended right hemicolectomy(LERH)for colon cancer.METHODS:Since its establishment in 2009,the Southern Chinese Laparoscopic Colorectal Surgical Study(SCLCSS)group has been dedicated to promoting patients’quality of life through minimally invasive surgery.The multicenter database was launched by combining existing datasets from members of the SCLCSS group.The study enrolled 220 consecutive patients who were recorded in the multicenter retrospective database and underwent either LERH(n=119)or open extended right hemicolectomy(OERH)(n=101)for colon cancer.Clinical characteristics,surgical outcomes,and oncologic outcomes were compared between the two groups.RESULTS:There were no significant differences in terms of age,gender,body mass index(BMI),history of previous abdominal surgery,tumor location,and tumor stage between the two groups.The blood loss was lower in the LERH group than in the OERH group[100(100-200)mL vs 150(100-200)mL,P<0.0001].The LERH group was associated with earlier first flatus(2.7±1.0 d vs 3.2±0.9 d,P<0.0001)and resumption of liquid diet(3.6±1.0 d vs 4.2±1.0 d,P<0.0001)compared to the OERH group.The postoperative hospital stay was significantly shorter in the LERH group(11.4±4.7 d vs 12.8±5.6 d,P=0.009)than in the OERH group.The complication rate was 11.8%and17.6%in the LERH and OERH groups,respectively(P=0.215).Both 3-year overall survival[LERH(92.0%)vs OERH(84.4%),P=0.209]and 3-year disease-free survival[LERH(84.6%)vs OERH(76.6%),P=0.191]were comparable between the two groups.CONCLUSION:LERH with D3 lymphadenectomy for colon cancer is a technically feasible and safe procedure,yielding comparable short-term oncologic outcomes to those of open surgery.

绿色包装的消费者接受意愿影响机制研究

目的探索心理因素如何影响消费者对绿色包装的接受意愿。方法首先,参考计划行为理论构建绿色包装的消费者接受意愿模型,然后依据模型假设开发调查问卷,并展开调查,最后对调查所得的417份有效调查问卷进行信度、效度检验,并用AMOS 17.0软件对样本数据和假设模型进行结构方程模型拟合检验。结果消费者对绿色包装的感知有用性、知觉行为控制和环保责任意识对消费者接受意愿有显著影响;绿色包装的感知易用性、消费者对环保的后果意识以及知觉行为控制三者之间相互影响显著。结论绿色包装的有用性、易用性,消费者的环保责任意识以及充分的宣传教育是提升消费者接受意愿的关键。

黏土中桩靴底部吸附力产生机理研究

在海洋工程中,移动钻井平台在作业结束后需要转场时,经常会遇到拔桩困难的问题,桩靴底部的吸附力是上拔力的重要组成部分,明确其产生机理及发展规律对于上拔力计算与缓解上拔困难问题有重要意义。通过室内模型试验研究了黏土中桩靴底部真空度对桩靴吸附力产生机理的影响,试验结果表明,桩靴底部真空度的变化对上拔力的影响显著,而桩靴贯入深度和上拔速率会对真空度产生影响。当真空度达到峰值时,桩靴底部吸附力与上拔力几乎同时达到峰值,因此可以通过减小桩靴底部真空度的措施来减小上拔力。根据试验结果,提出了运用真空吸盘理论来计算桩靴底部吸附力的计算公式。所述吸附力计算方法与试验结果进行对比,其误差较小,对工程实践具有一定的参考意义。

校园快递众包物流参与意愿影响机制研究

研究大学生对众包物流参与意愿的影响因素,首先基于TPB构建校园快递众包物流参与意愿模型,然后运用调查问卷的方式进行调查、获取研究数据,最后对收集到的有效问卷进行信度和效度检验,运用Amos24.0进行结构方程模型拟合检验。研究表明:促进条件、社会影响、态度、努力期望四个因素对校园快递众包物流参与意愿具有正向显著影响,收益期望对态度具有正向显著影响。由此得出结论:建立合理的定价机制和激励机制、注重平台建设、构建精准的数据分析系统是提高校园快递众包物流参与意愿的关键。

基于室内抗拔模型试验的黏性土中基础吸附力研究

在海洋工程中,位于海底软黏土中的沉箱或桩靴等基础在上拔的过程中,往往会出现较大的抗拔力。利用室内模型试验研究了上拔过程中重力锚与粉质黏土之间的相互作用特性。试验结果表明:在相同试验条件下,重力锚平底基础底部的吸附力总体高于8键基础;在不考虑埋深的条件下,吸附力系数随着不排水抗剪强度的增加而降低;土体强度越大,基础底面与粉质黏土之间的相互作用越小。并且结合试验结果对几种常用吸附力经验公式和基于承载力推导的计算方法进行了对比评价,同时探讨了粉质黏土与基础底面相互作用对吸附力的影响。

在土木工程制图课程教学中引入教具——以AutoCAD为例

根据目前画法几何与土木工程制图学科发展形势,土木工程专业的学生亟需打好制图、识图的基础,并在此基础上培养出良好的设计意识、更完备的专业知识及创新能力,针对目前的教学现状和难题,笔者尝试在画法几何与土木工程制图课堂中引入CAD,把CAD当做引入课堂的教具,与画法几何、制图相结合,以过渡学生的识图过程,降低教学难度,培养空间思维能力、激发学习兴趣。

MCP-1、NF-κB表达与乳腺癌改良根治术患者预后的关系

目的探究单核细胞趋化蛋白1(monocyte chemotactic protein-1,MCP-1)、核因子κB(nuclear factor kappa-B,NF-κB)表达与乳腺癌改良根治术患者预后的关系。方法随机选取2020年1月—2022年1月如皋市人民医院收治的105例行乳腺癌改良根治术的患者作为研究对象。术后对患者进行为期1年的随访,观察患者术后预后情况。根据患者预后结果将其分为预后良好组和预后不良组,收集患者临床相关资料,检测患者血清中MCP-1、NF-κB表达水平,单因素及多因素logistic回归分析影响患者术后预后的因素,用受试者工作特征(receiver operating characteristic curve,ROC)曲线评估MCP-1、NF-κB检测对患者术后预后的预测价值。结果行改良根治术乳腺癌患者术后随访1年,其预后不良发生率为29.52%(31/105)。预后不良组血清MCP-1、NF-κB水平高于预后良好组(P<0.05)。预后不良组与预后良好组的年龄、BMI、肿瘤位置、美国麻醉师协会(American Society of Anesthesiologists,ASA)分级、病理类型、肿瘤直径、合并糖尿病占比、合并高血压占比差异均无统计学意义(P>0.05)。预后不良组临床分期为Ⅲa期、有淋巴结转移、低分化程度占比高于预后良好组,术后辅助化疗占比低于预后良好组(P<0.05)。多因素logistic回归分析结果显示,低分化程度(OR=2.553)、高MCP-1水平(OR=1.875)、高NF-κB水平(OR=2.352)是影响患者术后预后不良的独立危险因素(P<0.05)。ROC曲线分析显示,MCP-1预测患者术后预后结局的曲线下面积(area under the curve,AUC)为0.697,NF-κB预测AUC为0.768,二者联合预测的AUC为0.908。结论MCP-1、NF-κB是影响乳腺癌患者术后预后结果的危险因素。MCP-1、NF-κB对患者术后预后有一定的预测价值,其联合检测预测价值更高。

2014-2020年青岛市居民结直肠癌流行及疾病负担趋势分析

目的分析青岛市户籍居民不同性别、年龄组结直肠癌发病和死亡变化趋势以及疾病负担,为青岛市结直肠癌的防治提供策略。方法基于青岛市肿瘤发病和死亡监测系统,收集2014-2020年青岛市户籍居民结直肠癌发病和死亡数据,分别计算发病率、死亡率、年龄标化率、变化百分比(PC)及年度变化百分比(APC)。以2010年全国第六次人口普查资料为标准计算标化率。采用伤残调整寿命年(DALY)、过早死亡损失寿命年(YLL)和伤残损失寿命年(YLD)分析结直肠癌疾病负担。结果2014-2020年青岛市结直肠癌累积发病17040例,死亡8543例,标化发病率为15.71/10万,标化死亡率为7.12/10万。粗发病率和粗死亡率在>50岁快速上升,且粗发病率于80~<85岁达到高峰之后有所下降。<60岁居民累积粗发病率由2014年7.59/10万上升到2020年11.84/10万。7年间总体标化发病率APC为4.32%,t=3.862,P=0.012;其中男性居民标化发病率APC为4.53%,t=3.224,P=0.023;女性为4.20%,t=3.745,P=0.013。青岛市户籍居民2014-2020年结直肠癌每千人口YLL、YLD和DALY分别为1.62、0.10和1.72,男性高于女性且60~<70岁年龄组疾病负担最重。结论青岛市结直肠癌发病率男性高于女性且呈现上升趋势。青年居民发病率增幅明显,提示应加强青年人群结直肠癌预防和健康教育以及重视老年人健康保障工作。

青岛市成年人体质指数与冠心病发病关联的前瞻性研究

目的分析青岛市成年人体质指数(BMI)与冠心病发病之间的关联。方法研究对象来自中国慢性病前瞻性研究青岛市项目点,共纳入33355名30~79岁研究对象,采用Cox比例风险回归模型,分析BMI与冠心病发病的关联。结果调查对象平均随访9.2人年,共监测缺血性心脏病(IHD)2712例,主要冠心病事件(MCE)420例。多因素Cox回归分析显示,与体重正常或过低的人群相比,超重和肥胖人群IHD及MCE的风险增加,超重组发病风险分别增加了41%和87%,HR值(95%CI)分别为1.41(1.27~1.56)和1.87(1.43~2.44),肥胖组分别增加了91%和143%,HR值(95%CI)分别为1.91(1.72~2.13)和2.43(1.82~3.24)。结论超重和肥胖会增加IHD和MCE的发病风险。

厄他培南预防直肠癌高危手术部位感染的临床疗效分析

目的探讨厄他培南预防直肠癌术后手术部位感染的临床疗效及其影响因素分析。方法选取2010年3月到2022年3月在福建医科大学附属协和医院结直肠外科术前应用抗生素预防手术部位感染的直肠癌患者775例;通过倾向性评分匹配(PSM)后,共纳入230例术前应用抗生素预防手术部位感染的直肠癌患者,厄他培南组46例、非厄他培南组184例,对比厄他培南组和非厄他培南组预防直肠癌手术部位感染的疗效;采用Logistic回归单、多因素分析直肠癌手术部位感染的危险因素。结果厄他培南组患者表浅手术部位感染发生率低于非厄他培南组(8.7%vs.22.3%,P=0.038);单因素分析发现厄他培南(OR=4.317,P=0.038)、手术方式(P=0.0001)、肿瘤距离肛缘的距离(OR=0.718,P=0.011)、手术时间(OR=1.010,P=0.002)与直肠癌术后表浅手术部位感染密切相关;多因素分析结果表明:非厄他培南(OR=4.392,95%CI:1.325~14.564;P=0.016)、手术方式(APR手术,OR=25.65,95%CI:2.960~222.37;P=0.003)、手术时间(OR=1.011,95%CI:0.003~1.019;P=0.004)是直肠癌术后表浅手术部位感染的独立危险因素。结论厄他培南比非厄他培南组更有效预防直肠癌表浅手术部位感染,APR手术和手术时间长的直肠癌患者应积极应用厄他培南预防手术部位感染。

中国结直肠肿瘤经自然腔道取标本手术患者短期疗效与肿瘤学预后分析:一项5055例患者的数据库研究

经自然腔道取标本手术(NOSES)通过无切口理念与常规手术器械的结合,表现出极佳的微创效果,并带给患者全新的就医感受.目前,尽管NOSES已广泛用于结直肠肿瘤治疗,大量研究也表明相比常规腹腔镜手术,NOSES具有恢复快、创伤小、疼痛轻等优势,但绝大多数研究均为小样本、单中心回顾性研究.本研究旨在通过分析我国5055例结直肠肿瘤NOSES患者数据,进一步探讨NOSES的短期疗效与预后.研究对象中,经直肠NOSES占整体比例的90.3%,经阴道NOSES占9.7%.NOSES术后短期并发症发生率为14.1%,吻合口瘘发生率为4.9%,腹盆腔感染率为1.9%.患者3年总生存率为93.2%,无病生存率为82.2%,局部复发率为3.6%.研究结果提示NOSES具有较好的安全性与可行性,为其应用于结直肠肿瘤治疗提供了证据.

Anatomy of the perirectal fascia at the level of rectosacral fascia revisited

Background:The relative anatomical understanding of the perirectal fasciae is of paramount importance for the proper performance of total mesorectal excision(TME).This study was to demonstrate the planes of TME and validates the intraoperative findings using cadaveric observations.Methods:In this combined retrospective and prospective study,bilateral attachment of the rectosacral fascia(RSF)was observed in 28 cadaveric specimens(male,n=14;female,n=14).From January 2018 to December 2019,surgical videos of 67 patients who underwent laparoscopic TME at the Affiliated Union Hospital of Fujian Medical University(Fuzhou,China)were reviewed and interpreted with the cadaveric findings.Results:The RSF(synonym:Waldeyer’s fascia)is the end of the pre-hypogastric fascia at the level of S4 and comprises two layers(upper and lower).These two layers provide double fascial protection for the venous sacral plexus.It inserts into the fascia propria of the rectum along a broad horizontal arc that merges anterolaterally in an oblique downward direction until it meets the posterolateral merge of Denonvilliers’fascia at the lateral rectal ligament(LRL).This ligament does not look like a true ligament but is more likely to be a fascial combination that cushions the rectal innervation and middle rectal vessels.Conclusions:Understanding the lateral attachment of RSF and its contribution to LRL provides invaluable surgical guidance to dissect this critical area.Therefore,lateral dissection is proposed from the anterior to the posterior direction to find the correct plane that guarantees an intact mesorectal envelope to protect the important nearby nerve structures.

Morphology of the anterior mesorectum:a new predictor for local recurrence in patients with rectal cancer

Background:Pre-operative assessment with high-resolution magnetic resonance imaging(MRI)is useful for assessing the risk of local recurrence(LR)and survival in rectal cancer.However,few studies have explored the clinical importance of the morphology of the anterior mesorectum,especially in patients with anterior cancer.Hence,the study aimed to investigate the impact of the morphology of the anterior mesorectum on LR in patients with primary rectal cancer.Methods:A retrospective study was performed on 176 patients who underwent neoadjuvant treatment and curative-intent surgery.Patients were divided into two groups according to the morphology of the anterior mesorectum on sagittal MRI:(1)linear type:the anterior mesorectum was thin and linear;and(2)triangular type:the anterior mesorectum was thick and had a unique triangular shape.Clinicopathological and LR data were compared between patients with linear type anterior mesorectal morphology and patients with triangular type anterior mesorectal morphology.Results:Morphometric analysis showed that 90(51.1%)patients had linear type anterior mesorectal morphology,while 86(48.9%)had triangular type anterior mesorectal morphology.Compared to triangular type anterior mesorectal morphology,linear type anterior mesorectal morphology was more common in females and was associated with a higher risk of circumferential resection margin involvement measured by MRI(35.6%[32/90]vs.16.3%[14/86],P=0.004)and a higher 5-year LR rate(12.2%vs.3.5%,P=0.030).In addition,the combination of linear type anterior mesorectal morphology and anterior tumors was confirmed as an independent risk factor for LR(odds ratio=4.283,P=0.014).Conclusions:The classification established in this study was a simple way to describe morphological characteristics of the anterior mesorectum.The combination of linear type anterior mesorectal morphology and anterior tumors was an independent risk factor for LR and may act as a tool to assist with LR risk stratification and treatment selection.

Chylous ascites has a higher incidence after robotic surgery and is associated with poor recurrence-free survival after rectal cancer surgery

Background:Postoperative chylous ascites is an infrequent condition after colorectal surgery and is easily treatable.However,its effect on the long-term oncological prognosis is not well established.This study aimed to investigate the short-term and long-term impact of chylous ascites treated with neoadjuvant therapy followed by rectal cancer surgery and to evaluate the incidence of chylous ascites after different surgical approaches.Methods:A total of 898 locally advanced rectal cancer patients treated with neoadjuvant chemoradiotherapy followed by surgery between January 2010 and December 2018 were included.The clinicopathological data and outcomes of the patients with chylous ascites were compared with those of the patients without chylous ascites.The primary endpoint was recurrence-free survival(RFS).To balance baseline confounders between groups,propensity score matching(PSM)was performed for each patient with a logistic regression model.Results:Chylous ascites was detected in 3.8%(34/898)of the patients.The incidence of chylous ascites was highest after robotic surgery(6.9%,6/86),followed by laparoscopic surgery(4.2%,26/618)and open surgery(1.0%,2/192,P=0.021).The patients with chylous ascites had a significantly higher number of lymph nodes harvested(15.6 vs.12.8,P=0.009)and a 3-day longer postoperative hospital stay(P=0.017).The 5-year RFS rate was 64.5%in the chylous ascites group,which was significantly lower than the rate in the no chylous ascites group(79.9%;P=0.007).The results remained unchanged after PSM was performed.The chylous ascites group showed a nonsignificant trend towards a higher peritoneal metastasis risk(5.9%vs.1.6%,P=0.120).Univariate analysis and multivariate analysis confirmed chylous ascites(hazard ratio=3.038,P<0.001)as an independent negative prognostic factor for RFS.Conclusions:Considering the higher incidence of chylous ascites after laparoscopic and robotic surgery and its adverse prognosis,we recommend sufficient coagulation of the lymphatic tissue near the vessel origins,especially during minimally invasive surgery.

The“terminal line”:a novel sign for the identification of distal mesorectum end during TME for rectal cancer

Background:Although the clinical importance of complete,intact total mesorectal excision(TME)is the widely accepted standard for decreasing local recurrence of rectal cancer,the residual mesorectum still represents a significant component of resection margin involvement.This study aimed to use a visible intraoperative sign to detect the distal mesorectal end to ensure complete inclusion of the mesorectum and avoid unnecessary over-dissection.Methods:The distal mesorectum end was investigated retrospectively through a review of 124 operative videos at the Union Hospital of Fujian Medical University(Fujian,China)and Cleveland Clinic(Ohio,USA)by two independent surgeons who were blinded to each other.Furthermore,28 cadavers and 44 post-operative specimens were prospectively examined by hematoxylin and eosin(H&E)staining and Masson’s staining to validate and confirm the findings of the retrospective part.Univariate and multivariate analyses were carried out to detect the independent factors that can affect the visualization of the distal mesorectal end.Results:The terminal line(TL)is the distal mesorectal end of the transabdominal and transanal TME(taTME)and appears as a remarkable pearly white fascial structure extending posteriorly from 2 to 10 o’clock.Histopathological examination revealed that the fascia propria of the rectum merges with the presacral fascia at the TL,beyond which the mesorectum ends,with no further downward extension.In the retrospective observation,the TL was seen in 56.6%of transabdominal TME and 56.0%of taTME operations.Surgical approach and tumor distance from the anal verge were the independent variables that directly influenced the detection of the TL(P=0.03 and P=0.01).Conclusion: The TL is a visible sign where the transabdominal TME should end and the taTME should begin. Recognitionof the mesorectal end may impact the certainty of complete mesorectum inclusion. Further clinical trials are needed toconfirm the preliminary findings.