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Restraint effect of partition wall on the tunnel floor heave in layered rock mass
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作者 YANG Yunyun HUANG Da +2 位作者 ZHONG Zhu LIU Yang PENG Jianbing 《Journal of Mountain Science》 SCIE CSCD 2024年第7期2462-2479,共18页
The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered... The presence of horizontal layered rocks in tunnel engineering significantly impacts the stability and strength of the surrounding rock mass,leading to floor heave in the tunnel.This study focused on preparing layered specimens of rock-like material with varying thickness to investigate the failure behaviors of tunnel floors.The results indicate that thin-layered rock mass exhibits weak interlayer bonding,causing rock layers near the surface to buckle and break upwards when subjected to horizontal squeezing.With an increase in the layer thickness,a transition in failure mode occurs from upward buckling to shear failure along the plane,leading to a noticeable reduction in floor heave deformation.The primary cause of significant deformation in floor heave is upward buckling failure.To address this issue,the study proposes the installation of a partition wall in the middle of the floor to mitigate heave deformation of the rock layers.The results demonstrate that the partition wall has a considerable stabilizing effect on the floor,reducing the zone of buckling failure and minimizing floor heave deformation.It is crucial for the partition wall to be sufficiently high to prevent buckling failure and ensure stability.Through simulation calculations on an engineering example,it is confirmed that implementing a partition wall can effectively reduce floor heave and enhance the stability of tunnel floor. 展开更多
关键词 Layered rock floor heave Horizontal compression test Failure behavior Partition wall
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Curative effect of hydrogen peroxide combined with silver ion disinfection on pelvic floor dysfunction
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作者 Wei Zhou Hua Guo 《World Journal of Clinical Cases》 SCIE 2024年第21期4508-4517,共10页
BACKGROUND Pelvic floor dysfunction(PFD)is related to muscle fiber tearing during childbirth,negatively impacting postpartum quality of life of parturient.Appropriate and effective intervention is necessary to promote... BACKGROUND Pelvic floor dysfunction(PFD)is related to muscle fiber tearing during childbirth,negatively impacting postpartum quality of life of parturient.Appropriate and effective intervention is necessary to promote PFD recovery.AIM To analyze the use of hydrogen peroxide and silver ion disinfection for vaginal electrodes in conjunction with comprehensive rehabilitation therapy for postpartum women with PFD.METHODS A total of 59 women with PFD who were admitted to the hospital from May 2019 to July 2022 were divided into two groups:Control group(n=27)received comprehensive rehabilitation therapy and observation group(n=32)received intervention with pelvic floor biostimulation feedback instrument in addition to comprehensive rehabilitation therapy.The vaginal electrodes were disinfected with hydrogen peroxide and silver ion before treatment.Intervention for both groups was started 6 weeks postpartum,and rehabilitation lasted for 3 months.Pelvic floor muscle voltage,pelvic floor muscle strength,vaginal muscle voltage,vaginal muscle tone,pelvic floor function,quality of life,and incidence of postpartum PFD were compared between the two groups.RESULTS Before comprehensive rehabilitation treatment,basic data and pelvic floor function were not significantly different between the two groups.After treatment,the observation group showed significant improvements in the maximum voltage and average voltage of pelvic floor muscles,contraction time of type I and type II fibers,pelvic floor muscle strength,vaginal muscle tone,vaginal muscle voltage,and quality of life(GQOLI-74 reports),compared with the control group.The observation group had lower scores on the pelvic floor distress inventory(PFDI-20)and a lower incidence of postpartum PFD,indicating the effectiveness of the pelvic floor biostimulation feedback instrument in promoting the recovery of maternal pelvic floor function.CONCLUSION The combination of the pelvic floor biostimulation feedback instrument and comprehensive rehabilitation nursing can improve pelvic floor muscle strength,promote the recovery of vaginal muscle tone,and improve pelvic floor function and quality of life.The use of hydrogen peroxide and silver ion disinfectant demonstrated favorable antibacterial efficacy and is worthy of clinical application. 展开更多
关键词 Pelvic floor biostimulation feedback instrument Comprehensive rehabilitation therapy Postpartum pelvic floor dysfunction Vaginal electrode Disinfection with hydrogen peroxide and silver ion Nanocolloidal silver
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Botulinum toxin type A injection combined with biofeedback in the treatment of spastic pelvic floor syndrome
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作者 Fei-Fei Sun Yong-Qiang Chen +1 位作者 Zong-Lin Jiang Lin Ma 《World Journal of Clinical Cases》 SCIE 2024年第22期4905-4912,共8页
BACKGROUND Spastic pelvic floor syndrome(SPFS)is a refractory pelvic floor disease characterized by abnormal(uncoordinated)contractions of the external anal sphincter and puborectalis muscle during defecation,resultin... BACKGROUND Spastic pelvic floor syndrome(SPFS)is a refractory pelvic floor disease characterized by abnormal(uncoordinated)contractions of the external anal sphincter and puborectalis muscle during defecation,resulting in rectal emptation and obstructive constipation.The clinical manifestations of SPFS are mainly characterized by difficult defecation,often accompanied by a sense of anal blockage and drooping.Manual defecation is usually needed during defecation.From physical examination,it is commonly observed that the patient's anal muscle tension is high,and it is difficult or even impossible to enter with his fingers.AIM To investigate the characteristics of anorectal pressure and botulinum toxin A injection combined with biofeedback in treating pelvic floor muscle spasm syndrome.METHODS Retrospective analysis of 50 patients diagnosed with pelvic floor spasm syndrome.All patients underwent pelvic floor surface electromyography assessment,anorectal dynamics examination,botulinum toxin type A injection 100 U intramuscular injection,and two cycles of biofeedback therapy.RESULTS After the botulinum toxin A injection combined with two cycles of biofeedback therapy,the patient's postoperative resting and systolic blood pressure were significantly lower than before surgery(P<0.05).Moreover,the electromyography index of the patients in the resting stage and post-resting stages was significantly lower than before surgery(P<0.05).CONCLUSION Botulinum toxin A injection combined with biofeedback can significantly reduce pelvic floor muscle tension in treating pelvic floor muscle spasm syndrome.Anorectal manometry is an effective method to evaluate the efficacy of treatment objectively.However,randomized controlled trials are needed. 展开更多
关键词 Spastic pelvic floor syndrome Botulinum toxin A BIOFEEDBACK Anorectal pressure measurement Agachan constipation score
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Basic Characteristics of an Appropriate Waste Fillers for Solvent Free and Water-Borne Industrial Polymer Floors and Their Utilization
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作者 Jana Kosikova 《Journal of Civil Engineering and Architecture》 2024年第3期141-147,共7页
Recently the manufacture of epoxy coating and flooring materials begun to be under strong pressure to use more environmentally friendly raw materials in its composition.First tendency to reduce of solvents and diluent... Recently the manufacture of epoxy coating and flooring materials begun to be under strong pressure to use more environmentally friendly raw materials in its composition.First tendency to reduce of solvents and diluents contained in the materials appeared at the end of 90´s.This situation was supported by the Council of Europe in 2004 to reduce VOC emissions to zero till 2020.Solvent materials were thus largely replaced by solvent free materials from which the volatile substances are not released into the air.But pressure continued to increase,and over the past decade began to take centre stage water-based epoxy.On the Czech market solvent based material is still occasionally used,but predominant are solvent free materials.There are no commonly used materials containing wastes as fillers in new water-borne and solvent-free epoxy materials.Characteristics identification of the waste material as a potential filler is a set of properties that determine the limits of secondary raw materials or waste as a filler.This paper describes the basic characteristics which must be selected to meet the requirements,to affect negatively the workability,sedimentation,properties and behavior of the final floor system.Some materials must comply with special requirements,such as resistance to chemicals,etc.Next part of paper talks about utilization of polymer floors and their mechanical properties. 展开更多
关键词 Industrial polymer flooring materials waster fillers building materials
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Further Analysis of Machine Tool Dimensional Accuracy and Thermal Stability under Varying Floor Temperature
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作者 Joel Arumun Shadrack Abiola 《World Journal of Engineering and Technology》 2024年第2期258-273,共16页
Machining is as old as humanity, and changes in temperature in both the machine’s internal and external environments can be of great concern as they affect the machine’s thermal stability and, thus, the machine’s d... Machining is as old as humanity, and changes in temperature in both the machine’s internal and external environments can be of great concern as they affect the machine’s thermal stability and, thus, the machine’s dimensional accuracy. This paper is a continuation of our earlier work, which aimed to analyze the effect of the internal temperature of a machine tool as the machine is put into operation and vary the external temperature, the machine floor temperature. Some experiments are carried out under controlled conditions to study how machine tool components get heated up and how this heating up affects the machine’s accuracy due to thermally induced deviations. Additionally, another angle is added by varying the machine floor temperature. The parameters mentioned above are explored in line with the overall thermal stability of the machine tool and its dimensional accuracy. A Robodrill CNC machine tool is used. The CNC was first soaked with thermal energy by gradually raising the machine floor temperature to a certain level before putting the machine in operation. The machine was monitored, and analytical methods were deplored to evaluate thermal stability. Secondly, the machine was run idle for some time under raised floor temperature before it was put into operation. Data was also collected and analyzed. It is observed that machine thermal stability can be achieved in several ways depending on how the above parameters are joggled. This paper, in conclusion, reinforces the idea of machine tool warm-up process in conjunction with a carefully analyzed and established machine floor temperature variation for the approximation of the machine tool’s thermally stability to map the long-time behavior of the machine tool. 展开更多
关键词 Dimensional Accuracy Machine Tool Machine floor Thermal Stability TEMPERATURE Thermal Deviation
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Maxillary sinus floor augmentation: a review of current evidence on anatomical factors and a decision tree 被引量:1
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作者 Mingyue Lyu Dingyi Xu +1 位作者 Xiaohan Zhang Quan Yuan 《International Journal of Oral Science》 SCIE CAS CSCD 2023年第3期347-354,共8页
Maxillary sinus floor augmentation using lateral window and crestal technique is considered as predictable methods to increase the residual bone height;however,this surgery is commonly complicated by Schneiderian memb... Maxillary sinus floor augmentation using lateral window and crestal technique is considered as predictable methods to increase the residual bone height;however,this surgery is commonly complicated by Schneiderian membrane perforation,which is closely related to anatomical factors.This article aimed to assess anatomical factors on successful augmentation procedures.After review of the current evidence on sinus augmentation techniques,anatomical factors related to the stretching potential of Schneiderian membrane were assessed and a decision tree for the rational choice of surgical approaches was proposed.Schneiderian membrane perforation might occur when local tension exceeds its stretching potential,which is closely related to anatomical variations of the maxillary sinus.Choice of a surgical approach and clinical outcomes are influenced by the stretching potential of Schneiderian membrane.In addition to the residual bone height,clinicians should also consider the stretching potential affected by the membrane health condition,the contours of the maxillary sinus,and the presence of antral septa when evaluating the choice of surgical approaches and clinical outcomes. 展开更多
关键词 STRETCHING floor TREE
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Minimally invasive techniques for lateral maxillary sinus floor elevation: small lateral window and one-stage surgery—a 2–5-year retrospective study
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作者 Shaojingya Gao Yao Jiang +2 位作者 Yangxue Yao Songhang Li Xiaoxiao Cai 《International Journal of Oral Science》 SCIE CAS CSCD 2023年第3期401-410,共10页
This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach(lSFE)and to determine the factors that influence the stability of the grafted area in the sin... This study aimed to introduce a minimally invasive technique for maxillary sinus floor elevation using the lateral approach(lSFE)and to determine the factors that influence the stability of the grafted area in the sinus cavity.Thirty patients(30 implants)treated with lSFE using minimally invasive techniques from 2015 to 2019 were included in the study.Five aspects of the implant(central,mesial,distal,buccal,and palatal bone heights[BHs])were measured using cone-beam computed tomography(CBCT)before implant surgery,immediately after surgery(T0),6 months after surgery(T1),and at the last follow-up visit(T2).Patients’characteristics were collected.A small bone window(height,(4.40±0.74)mm;length,(6.26±1.03)mm)was prepared.No implant failed during the follow-up period(3.67±1.75)years.Three of the 30 implants exhibited perforations.Changes in BH of the five aspects of implants showed strong correlations with each other and BH decreased dramatically before second-stage surgery.Residual bone height(RBH)did not significantly influence BH changes,whereas smoking status and type of bone graft materials were the potentially influential factors.During the approximate three-year observation period,lSFE with a minimally invasive technique demonstrated high implant survival rate and limited bone reduction in grafted area.In conclusion,lSFE using minimally invasive techniques was a viable treatment option.Patients who were nonsmokers and whose sinus cavity was filled with deproteinized bovine bone mineral(DBBM)had significantly limited bone resorption in grafted area. 展开更多
关键词 SURGERY viable floor
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Experimental Mode and Vibration Comfort Analysis of High-Rise Glulam Building Floor Structure
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作者 Yuhang He Rongzhuo Zhang +1 位作者 Yifan Zhang Zheng Wang 《Journal of Renewable Materials》 SCIE EI 2023年第6期2729-2743,共15页
In order to better meet the objective requirements of the use safety of the high-rise glulam building floor structure and the living comfort of the residents,the transient excitation,environmental excitation and frequ... In order to better meet the objective requirements of the use safety of the high-rise glulam building floor structure and the living comfort of the residents,the transient excitation,environmental excitation and frequency spectrum identification methods were used to carry out experimental modal test in-site on the three rooms numbered A,B and C of the same glulam structural building.The three rooms have different functions,different floor sizes and different floor supporting structures.The research results have shown that the first-order bending frequency of the floor structure of Room A is 27.50 Hz,the transverse second-order bending frequency is 34.75 Hz,the longitudinal second-order bending frequency is 53.25 Hz,and the first-order torsional frequency is 56.25 Hz.The reinforced wooden beam at the bottom of the floor of Room A increases the transverse stiffness of the floor structure,but does not offset the anisotropy caused by the longitudinally installed glulam floors.The fundamental frequency values of the floor structures of the three rooms numbered A,B,and C are 27.5,13 and 18 Hz,respectively.This has a relatively high innovation and reference significance for integrating the theory of structural dynamic characteristics with the dynamic testing technology,improving the design level of high-rise glulam structure buildings,and improving the living comfort of residents. 展开更多
关键词 Glulam building wooden floor experimental mode vibration comfort fundamental frequency
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Reporting Children’s Development below the Test Floor: Looking Back and Forth to Describe Individual Strengths and Needs
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作者 Elizabeth M. Green Louise A. Stroud 《Health》 CAS 2023年第2期122-133,共12页
The test floor effects seen in standardised tests lead to a standardised score of 1 or less with a flat profile that hides a child’s individual strengths and needs. The Griffiths III community of practitioners reques... The test floor effects seen in standardised tests lead to a standardised score of 1 or less with a flat profile that hides a child’s individual strengths and needs. The Griffiths III community of practitioners requested advice on the reporting of children’s development below the floor of the test, so that individual strengths and needs can be described. This paper reports the third phase of research following an earlier Scoping Review and a wider literature review. To confirm quality control, Phase 3 was conducted in a retrospective manner using the same methodology as the earlier phases but in a reverse direction. Peer reviewer comments and key elements from the Scoping Review and keywords from the publications were tabulated. Data analysis included a change of perspective to that of the child and their individual rights with respect to the literature themes already described in Phase 2. These confirmed that there is little specific guidance in the literature, but that computational advances for homogeneous populations and especially disaggregated data offer some solutions. A greater balance between broad biopsychosocial models and standardised models of assessment should be sought by practitioners together with the use of disaggregated data to highlight issues that pertain to individual subsets of results. This will ensure that the child’s right for their individual strengths and needs to be described together with a plan for management, may be met. 展开更多
关键词 Developmental Assessment Children with Severe Disability Disaggregated Data Pattern and Needs Identification Below Test floor
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Effects of High Risk Pregnancy Factors on Pelvic Floor Muscle Weakness and Changes of PG, ACTH and CRP
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作者 Yu Han Haiyan Lin +6 位作者 Jiu Du Lianfang Chen Xianmei Wei Peijia Wei Biyun Zhou Xiangli Feng Siran Chen 《Open Journal of Obstetrics and Gynecology》 2023年第9期1569-1579,共11页
Objective: To investigate the effects of different delivery modes on perinatal pelvic floor muscle strength, PG, ACTH and CRP of high-risk pregnant women. Methods: 380 high-risk pregnant women who gave birth in our ho... Objective: To investigate the effects of different delivery modes on perinatal pelvic floor muscle strength, PG, ACTH and CRP of high-risk pregnant women. Methods: 380 high-risk pregnant women who gave birth in our hospital from March 2021 to February 2022 were selected as subjects, including 100 vaginal natural delivery, 156 forceps assisted delivery and 124 cesarean section. Pelvic floor pressure, PG, ACTH, CRP, IL-6, TNF-α and IL-4, IL-10 levels were evaluated and compared. The perinatal occurrence of pelvic floor functional disease (PFD) in high-risk pregnant women in each group was analyzed and evaluated. Results: There were statistical differences in the amount of postpartum blood loss (P 0.0001, F = 99.01), postpartum blood loss 24 h (P = 0.0004, F = 19.54) and hospital stay (P 0.0001, F = 70.81) among the three groups of high-risk women in natural vaginal delivery, forceps delivery and cesarean section. In addition, there were 72, 134 and 70 cases of abnormal pelvic floor fatigue in natural vaginal delivery, forceps assisted delivery and cesarean section (P 0.0001, χ<sup>2</sup> = 30.16). There were 36, 79 and 21 cases of muscle injury, respectively (P 0.0001, χ<sup>2</sup> = 34.16). There were 49, 98 and 43 cases of dysmuscular contraction, respectively (P 0.0001, χ<sup>2</sup> = 21.94). There were 65, 120 and 41 cases with vaginal dynamic pressure 80 cm H<sub>2</sub>O (P 0.0001, χ<sup>2</sup> = 56.86), respectively. The. 展开更多
关键词 High-Risk Pregnant Women Pelvic floor Muscle Strength Stress Response Inflammatory Response
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经会阴盆底超声参数对盆底功能障碍性疾病的监测效果及对盆底康复治疗的指导价值 被引量:1
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作者 李静 刘瑞明 +4 位作者 王文荣 朱媛 李仰懿 彭娜娜 杨振冬 《中国性科学》 2024年第1期62-66,共5页
目的探究经会阴盆底超声参数对盆底功能障碍性疾病(PFD)的监测效果及对盆底康复治疗的指导价值。方法选取2021年1月至2022年6月江苏省连云港市妇幼保健院119例产后42 d发现的PFD患者作为研究对象,根据分娩情况分为初产妇组(n=59)和经产... 目的探究经会阴盆底超声参数对盆底功能障碍性疾病(PFD)的监测效果及对盆底康复治疗的指导价值。方法选取2021年1月至2022年6月江苏省连云港市妇幼保健院119例产后42 d发现的PFD患者作为研究对象,根据分娩情况分为初产妇组(n=59)和经产妇组(n=60)。比较两组及不同分娩方式患者盆底超声参数,所有患者均行盆底康复治疗,治疗1个月后统计疗效,分析各参数预测疗效的价值。结果经产妇组尿道旋转角、膀胱后角、膀胱移动度、肛提肌裂孔面积(最大Valsalva动作)均高于初产妇组(P<0.05);两组中自然分娩孕妇尿道旋转角、膀胱后角、膀胱移动度、肛提肌裂孔面积(最大Valsalva动作)均高于剖宫产孕妇(P<0.05);疗效不佳的PFD患者治疗前的尿道旋转角、膀胱后角、膀胱移动度、肛提肌裂孔面积(最大Valsalva动作)均高于疗效良好的患者(P<0.05)。治疗前尿道旋转角、膀胱后角、膀胱移动度、肛提肌裂孔面积(最大Valsalva动作)预测PFD患者盆底康复疗效不佳的曲线下面积(AUC)分别为0.821、0.771、0.732、0.703。结论经会阴盆底超声参数可监测PFD病情,且能为临床预测盆底康复疗效、判断疾病转归提供参考。 展开更多
关键词 盆底功能障碍性疾病 超声 剖宫产 自然分娩 盆底康复治疗
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Two Cases of Epidermoid Cyst of the Buccal Floor Simulating: A Tumour of the Submandibular Gland
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作者 Aminata Mbaye Ndeye Fatou Thiam +3 位作者 Ababacar Diegane Faye Mouminatou Seye Houra Ahmed Cire Ndiaye 《International Journal of Otolaryngology and Head & Neck Surgery》 2023年第5期301-308,共8页
Dermoid cyst of the oral floor is rare benign tumour, who having three histological aspects: dermoid, teratoid and epidermoid. This one is characterized by the presence of a squamous stratified epithelium with cutaneo... Dermoid cyst of the oral floor is rare benign tumour, who having three histological aspects: dermoid, teratoid and epidermoid. This one is characterized by the presence of a squamous stratified epithelium with cutaneous remnants. It may occur in any part of the body, however their frequency in the ENT sphere is relatively scarce. Seven per cent (7%) only of epidermoid cysts occur in the cervico-facial area, 1.6% of which locate at the floor level. When they are located submandibular, they can pose diagnostic difficulties and look like a tumour of the submaxillary gland. We report two cases of epidermoid cyst of the floor. Both patients suffered from swelling of the submandibular gland. Magnetic Resonance Imaging was not requested due to lack of resources. However, surgery allowed in both cases the excision of a cyst next to a normal submandibular gland. Patients did well post operatively. 展开更多
关键词 Epidermoid Cyst Mouth floor Submandibular Gland SURGERY TUMOUR
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腹腔镜子宫肌瘤剔除术对子宫肌瘤患者盆底功能、卵巢功能的影响 被引量:1
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作者 张琳 张颖 徐流立 《临床研究》 2024年第1期80-83,共4页
目的探讨腹腔镜子宫肌瘤剔除术(LM)对子宫肌瘤患者盆底功能、卵巢功能的影响。方法纳入2021年1月至2022年10月濮阳市安阳地区医院收治的80例子宫肌瘤患者,按抽签法分两组。对照组40例行开腹子宫肌瘤剔除术(AM),研究组40例行LM,对比两组... 目的探讨腹腔镜子宫肌瘤剔除术(LM)对子宫肌瘤患者盆底功能、卵巢功能的影响。方法纳入2021年1月至2022年10月濮阳市安阳地区医院收治的80例子宫肌瘤患者,按抽签法分两组。对照组40例行开腹子宫肌瘤剔除术(AM),研究组40例行LM,对比两组手术前后疼痛因子[心肌细胞P物质(SP)、前列腺素E_2(PGE_2)]、应激反应指标[去甲肾上腺素(NE)、皮质醇(COR)]、免疫功能指标(CD3^(+)、CD4^(+)、CD8^(+)、CD4^(+)/CD8^(+))、盆底功能指标[盆底障碍影响简易问卷7(PFIQ-7)]及卵巢功能指标[雌二醇(E_2)、促黄体生成素(LH)、促卵泡激素(FSH)]。结果术后1 d、术后3 d时,研究组血清SP、PGE_2、NE、COR水平低于对照组,差异有统计学意义(P<0.05)。术后1d时,两组CD3^(+)、CD4^(+)及CD4^(+)/CD8^(+)功能指标与术前相比均有所降低,但研究组明显高于对照组,差异有统计学意义(P<0.05);而两组的CD8^(+)功能指标与术前相比有所升高,但研究组明显低于对照组,差异有统计学意义(P<0.05)。术后1个月、术后3个月时,两组PFIQ-7评分均有所升高,但研究组明显低于对照组,差异有统计学意义(P<0.05)。术后3个月、术后6个月时,研究组血清E_2水平高于对照组,而血清LH、FSH水平低于对照组,差异有统计学意义(P<0.05)。结论对子宫肌瘤患者行LM可有效减轻机体疼痛程度、应激反应及对免疫、盆底和卵巢功能的负面影响,优势较为显著,具有进一步的使用价值。 展开更多
关键词 子宫肌瘤 腹腔镜子宫肌瘤剔除术 盆底功能 卵巢功能
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特厚煤层底板断层破坏与顶板垮断联动效应的CFDEM模拟研究
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作者 李浩 唐世斌 +2 位作者 康志勤 杨栋 马立强 《煤炭学报》 EI CAS CSCD 北大核心 2024年第6期2615-2629,共15页
特厚煤层采场空间大、覆岩扰动范围广,顶板垮断产生的强扰动加卸荷载易导致底板断层破坏加剧。通过数值模拟研究特厚煤层底板断层突水与顶板垮断联动效应机理规律是开展水害防治的基础,关键在于掌握加卸载下岩体渐进破坏与裂隙流耦合特... 特厚煤层采场空间大、覆岩扰动范围广,顶板垮断产生的强扰动加卸荷载易导致底板断层破坏加剧。通过数值模拟研究特厚煤层底板断层突水与顶板垮断联动效应机理规律是开展水害防治的基础,关键在于掌握加卸载下岩体渐进破坏与裂隙流耦合特征。构建加卸载下拉、剪损伤演化方程,结合有效偏/球应力为基本变量的屈服准则与塑性势函数,得到完整岩块的塑性损伤本构;建立拉/剪、混合型加卸载过程中塑性位移与强度劣化关系,以平方拉剪应力与B-K准则为初始、完全断裂准则,形成非贯通裂隙断裂本构;提出岩块分离、压缩、剪切判据,结合实验数据建立离散块体间挤压、剪切摩擦本构与剪胀方程。基于质量/动量守恒、状态方程,并结合流体体积与浸没边界方法,形成裂隙岩体气−水二相流模拟理论。由此形成CFDEM数值计算程序,并将加卸载下塑性损伤、断裂、挤压/摩擦、流体属性分别赋予实体单元(岩块)、黏聚力单元(非贯通裂隙)、接触对(贯通裂隙)、欧拉单元(水和气)。根据宁武煤田北部矿区工程地质条件,建立特厚煤层底板断层突水与顶板垮断联动效应数值计算模型。结果表明:①CFDEM耦合程序及相应的理论模型可数值实现特厚煤层覆岩及底板断层从(准)连续体到离散体转化,以及地下水在裂隙中运移;②模拟条件下特厚煤层含断层底板的采动裂隙包络线呈w形,最深处超过55 m位于断层及其上盘,最浅处23 m位于断层下盘,而无构造底板处的破坏深度为24~36 m,已导通奥灰含水层;③特厚煤层底板普遍出现二次破坏现象。表现为无构造底板在超前工作面处破坏深度为24.0~29.3 m,但在采空区内普遍增加至31.5~36.0 m;断层及其上盘在超前工作面处裂隙总开度为0.34~0.86 m,但在采空区内迅速增加至3.6 m,形成突水优势通道。④底板断层突水与顶板垮断联动效应的根源在于覆岩高位关键岩层垮断失稳、砌体梁下沉与二次断裂,并导致底板二次破坏,突水风险加剧。 展开更多
关键词 特厚煤层 底板断层突水 顶底板联动效应 CFDEM程序 微震实验
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陕西省煤矿典型水灾隐患特征及治理技术 被引量:2
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作者 董书宁 樊敏 +5 位作者 郭小铭 刘英锋 郭康 姬中奎 李超峰 薛小渊 《煤炭学报》 EI CAS CSCD 北大核心 2024年第2期902-916,共15页
陕西省煤炭资源丰富,2022年煤炭产量达7.46亿t,是我国主要产煤省份之一。由于全省煤矿区地质及水文地质条件差异明显,煤矿水灾类型多样,随着近年煤炭开采强度的增大,水灾事故时有发生,防治水形势较为严峻。以煤炭赋存条件为基础,系统总... 陕西省煤炭资源丰富,2022年煤炭产量达7.46亿t,是我国主要产煤省份之一。由于全省煤矿区地质及水文地质条件差异明显,煤矿水灾类型多样,随着近年煤炭开采强度的增大,水灾事故时有发生,防治水形势较为严峻。以煤炭赋存条件为基础,系统总结区域水文地质结构特征,界定典型水灾类型及各类水灾影响区域分布,论述典型水灾的形成机理及特征,并提出了相应的防控技术。研究表明:(1)陕西省主要煤炭产区分为陕北、黄陇、渭北三大区,陕北侏罗纪煤田主要有顶板松散沙层水灾隐患、厚层砂岩水灾隐患、溃水溃沙灾害,局部区域分布有烧变岩对煤矿造成水灾隐患;黄陇煤田主要受顶板巨厚砂岩水灾隐患、离层溃水隐患、泥砂溃涌灾害隐患威胁;陕北石炭—二叠纪煤田和渭北煤田,主要受到煤层底板奥陶系灰岩水灾隐患威胁。(2)陕北侏罗系煤田顶板水灾隐患主要为顶板含水层受开采导水裂隙带扰动形成,导水裂隙波及砂岩含水层或松散沙层可形成持续大流量涌水,部分区域充水强度较大,在短时间水量较大超过排水系统能力时造成顶板水灾,在薄基岩区域垮落带直接导通松散沙层时可转变为溃水溃沙灾害,导水裂隙带影响到烧变岩富水区域时可形成瞬时水量大且持续的烧变岩水灾;黄陇煤田顶板巨厚砂岩含水层受采动导水裂隙带波及形成高强度持续涌水并可能形成顶板水灾,当含水层下部隔水层厚度较大时,可能形成离层溃水灾害,当近煤层顶板岩层松软遇水易崩解时可转变为泥砂溃涌灾害;陕北石炭—二叠纪煤田和渭北煤田,煤层开采底板扰动破坏带或断层等构造导通奥陶系灰岩含水层时,会引发极为严重的底板突水灾害,该类灾害具突发性强、瞬时水量大的特征。(3)各区域的顶板水灾隐患治理技术主要包括钻孔疏泄、注浆治理、开采参数控制等,底板水灾隐患治理技术主要包括区域注浆加固及封堵等;烧变岩水灾隐患主要采取帷幕注浆与钻孔探放有机结合的防治技术。 展开更多
关键词 陕西省煤矿 溃水溃沙 烧变岩水灾 离层溃水 泥砂溃涌 底板奥灰水灾
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术前盆底肌电生理参数对前列腺癌根治性切除术后早期尿失禁的预测价值
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作者 于书慧 韩佳凝 +5 位作者 钟丽君 陈聪语 肖云翔 黄燕波 杨洋 车新艳 《北京大学学报(医学版)》 CAS CSCD 北大核心 2024年第4期594-599,共6页
目的:探索术前盆底肌电生理参数对前列腺癌术后尿失禁风险的预测价值。方法:选择2020年1月至2022年10月在北京大学第一医院泌尿外科行根治性前列腺切除术患者的病例资料进行回顾性分析,记录患者的年龄、体重指数(body mass index,BMI)... 目的:探索术前盆底肌电生理参数对前列腺癌术后尿失禁风险的预测价值。方法:选择2020年1月至2022年10月在北京大学第一医院泌尿外科行根治性前列腺切除术患者的病例资料进行回顾性分析,记录患者的年龄、体重指数(body mass index,BMI)、国际前列腺症状评分(international prostate symptom score,IPSS)、前列腺特异性抗原(prostate-specific antigen,PSA)水平、Gleason评分、手术方式、是否尿道功能重建、是否淋巴结清扫、性神经是否保留、留置导尿时间、D’Amico风险分级、美国麻醉医师协会(American Society of Anesthesiologists,ASA)评分、查尔森(Charlson)合并症指数、术后随访时间、前列腺体积,以及盆底肌电生理参数(前静息均值、快肌均值和慢肌均值)。通过多因素Logistic回归分析,筛选出影响术后早期尿失禁发生的独立危险因素,并通过计算受试者工作特征曲线(receiver operating characteristic,ROC)下面积,评估盆底肌电参数的预测效能,再利用约登指数(Youden index)并结合临床意义,共同确定术后早期尿失禁发生的最佳临界值。结果:纳入患者271例,术后自主控尿率为81.9%。患者快肌评分为23.5(18.2,31.6)分,慢肌评分为12.5(9.6,17.3)分,179例(66.1%)患者未保留性神经,110例(40.6%)患者进行了尿道功能重建。高龄和盆底快肌评分低被确认为尿失禁发生的独立危险因素。≤60岁患者是≥70岁患者自主控尿率的5.482倍(95%CI:1.532~19.617,P<0.05);患者的盆底快肌评分与尿失禁恢复的关系密切(OR=1.209,95%CI:1.132~1.291,P<0.05)。当术前盆底快肌评分的最佳临界值设定为18.5分时,ROC的敏感度和特异度分别为80.6%和61.2%。结论:术前盆底肌电生理参数对于前列腺癌术后尿失禁风险表现出较好的预测准确性和临床应用性,能够用于前列腺癌术后尿失禁风险的早期识别,其中年龄和盆底快肌评分是重要的预测因子。 展开更多
关键词 盆底肌电生理参数 前列腺癌根治性切除 尿失禁
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国家标准GB/T 18103—2022《实木复合地板》解读
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作者 王瑞 唐召群 +4 位作者 吕斌 伍艳梅 张鹏 张玉萍 孟凡丹 《木材科学与技术》 北大核心 2024年第2期75-80,共6页
国家标准GB/T 18103—2022《实木复合地板》已于2022年12月30发布,2023年7月1日实施。简述标准修订过程、修订原则和内容变化,通过对标准术语和定义、分类、要求、检验方法、检验规则以及标识、包装、运输和贮存等的解读,引导标准的正... 国家标准GB/T 18103—2022《实木复合地板》已于2022年12月30发布,2023年7月1日实施。简述标准修订过程、修订原则和内容变化,通过对标准术语和定义、分类、要求、检验方法、检验规则以及标识、包装、运输和贮存等的解读,引导标准的正确理解和实施应用。 展开更多
关键词 实木复合地板 国家标准 修订 理化性能要求
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海底氢气成藏模式与全球分布
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作者 索艳慧 姜兆霞 +1 位作者 李三忠 吴立新 《地学前缘》 EI CAS CSCD 北大核心 2024年第4期175-182,共8页
氢能是一种清洁、高效、零碳的顶极能源。天然氢的形成和运聚与板块构造活动密切相关。地球作为整个太阳系已知唯一发育有板块构造和表面存在液态水的岩质星球,具备地球脱气、蛇纹岩水岩反应、水辐射分解等独特的地质生氢路径。占据现... 氢能是一种清洁、高效、零碳的顶极能源。天然氢的形成和运聚与板块构造活动密切相关。地球作为整个太阳系已知唯一发育有板块构造和表面存在液态水的岩质星球,具备地球脱气、蛇纹岩水岩反应、水辐射分解等独特的地质生氢路径。占据现今地球表面面积2/3的海底,发育洋壳甚至有地幔物质的直接剥露,具备蛇纹石化形成天然氢的巨大潜力。海底天然氢有沿微板块边界的大量氢气产出机制和海底裂缝导致的海底渗透型的另类机制,现今海底微板块边界、洋底高原、海底裂隙系统、沿超慢速-慢速洋中脊和非火山型被动陆缘出露的微幔块都是寻找天然氢的有利目标,南海东北陆缘的“陆壳裂洞”也十分值得关注。由于不同构造环境的天然氢的形成和储存条件存在较大差异,天然氢在生成、运移和存储等方面存在多样性和差异性,因此难以建立一套统一的氢气成藏模式,也无法精准确定潜在资源量。已有的氢气显示和预测的有利生氢场所,能否成藏、成藏机制如何以及如何开发利用,也依然是未来需要探索的问题。 展开更多
关键词 海底氢气藏 成藏模式 蛇纹石化 微板块 热液系统 海底裂隙
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RPG整体姿态康复技术联合盆底电刺激、手法按摩治疗MFPP的临床疗效
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作者 吴菲 罗军 +1 位作者 刘莉 龙婷 《医学临床研究》 CAS 2024年第5期641-644,共4页
【目的】探讨RPG整体姿态康复技术联合盆底电刺激、手法按摩治疗肌筋膜源性慢性盆腔痛(MFPP)的临床疗效。【方法】选取2020年3月至2023年12月在本院盆底诊治中心就诊的80例MFPP的女性患者,采用随机数字表法分为观察组和对照组,每组40例... 【目的】探讨RPG整体姿态康复技术联合盆底电刺激、手法按摩治疗肌筋膜源性慢性盆腔痛(MFPP)的临床疗效。【方法】选取2020年3月至2023年12月在本院盆底诊治中心就诊的80例MFPP的女性患者,采用随机数字表法分为观察组和对照组,每组40例。两组均接受电刺激治疗、手法按摩及盆底肌肉锻炼治疗1个疗程,观察组同时给予RPG整体姿态康复训练。比较两组治疗后有效率及治疗前后盆腔肌筋膜疼痛程度、异常体态改善情况。【结果】观察组治疗有效率为87.50%,与对照组的80.00%比较,差异无统计学意义(P>0.05)。盆腔左侧、盆腔右侧、闭孔内肌、梨状肌、混合性等5个部位疼痛比较,差异均无统计学意义(P>0.05)。治疗后,两组中度、重度疼痛患者占比均较治疗前明显减少(P<0.05),且观察组无疼痛患者占比显著高于对照组(P<0.05)。观察组患者异常体态改善有效率为57.33%,与对照组患者的37.50%比较,差异无统计学意义(P>0.05)。【结论】RPG整体姿态康复技术联合盆底电刺激、手法按摩可显著减轻MFPP患者的疼痛程度,是治疗MFPP安全、有效的方法,长期疗效有待进一步观察。 展开更多
关键词 骨盆底/损伤 盆底疾病/按摩疗法 慢性病 电刺激疗法
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西准噶尔构造带包古图组的岩石组合及其时限
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作者 李永军 李伟 +5 位作者 王绪龙 段丰浩 朱钊 郑孟林 杨高学 张越迁 《地质学报》 EI CAS CSCD 北大核心 2024年第7期2053-2063,共11页
包古图组是新疆西准噶尔增生造山带西北缘石炭纪密西西比亚纪重要沉积记录。确认其完整的沉积序列、岩石组合及其与上覆和下伏地层的接触关系,对解析本区晚古生代盆地构造演化具有重要意义。本文新实测的白碱滩北红山梁剖面上,出露了岩... 包古图组是新疆西准噶尔增生造山带西北缘石炭纪密西西比亚纪重要沉积记录。确认其完整的沉积序列、岩石组合及其与上覆和下伏地层的接触关系,对解析本区晚古生代盆地构造演化具有重要意义。本文新实测的白碱滩北红山梁剖面上,出露了岩石组合截然有别,色调区分性极强的两大套地层,上部深灰—灰黑色调“(含碳)细碎屑岩”与其下伏鲜红色调的“硅质岩-凝灰质硅质粉砂岩间夹中基性火山岩”为连续沉积(整合接触),分属包古图组和红山梁组。本文于包古图组底部和红山梁组顶部分别获得345.1 Ma和365.9 Ma的LA-ICP-MS锆石U-Pb年龄,限定其时代分别为密西西比亚纪和晚泥盆世。这一新发现,不仅确立了包古图组是区内石炭纪最老地层单位,佐证了包古图组老于希贝库拉斯组这一久争悬疑,而且使得区内密西西比亚系有了完整的地层序列,揭秘了石炭系最底部的沉积建造及其岩石组合,也为完整认识泥盆纪—石炭纪这一重要时期的盆地沉积特征及其构造演化提供了新资料。 展开更多
关键词 密西西比亚系包古图组 岩石组合 顶底时限 锆石U-PB年龄 西准噶尔构造带
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