Mandibular left first premolar with three roots and three canals:A case report

BACKGROUND The numbers of mandibular first premolar roots and root canals vary,and the incidence of three roots and three canals is 0.09%.CASE SUMMARY In this article,we review the root and root canal conditions for the mandibular first premolar and report the case of a mandibular left first premolar with three roots and three canals in a male patient,with suggestions for clinical diagnosis and treatment.The patient was referred by an orthodontist for the extraction of the tooth.Preoperative cone-beam computed tomography examination revealed that it had three roots.Under local anesthesia,the extraction socket was carefully expanded,and the tooth was successfully removed intact using forceps.The procedure was uneventful,with no root fractures,postoperative bleeding,or sensory abnormality observed.CONCLUSION The mandibular first premolar is characterized by multiple roots and canal variations that can increase the difficulty of treatment.

Complete resection of recurrent anal canal cancer using endoscopic submucosal dissection and transanal resection: A case report

BACKGROUND Early anal canal cancer is frequently treated with endoscopic submucosal dis-section(ESD)to preserve anal function.However,if the lesion is in the anal canal,then significant difficulties such as bleeding and challenges associated with scope manipulation can arise.CASE SUMMARY A 70-year-old woman undergoing follow-up after transverse colon cancer surgery was diagnosed with anal canal cancer extending to the dentate line.The patient underwent a combination of ESD and transanal resection(TAR).The specimen was excised in pieces,which resulted in difficulty performing the pathological evaluation of the margins,especially on the anal side where TAR was performed and severe crushing was observed.Careful follow-up was performed,and local recurrence was observed 3 years postoperatively.Because the patient had super-ficial cancer without lymph node metastasis,local resection was performed again.The second treatment attempt was improved as follows:(1)TAR and ESD were performed appropriately based on the situation by the same physician;(2)A needle scalpel was used during TAR to prevent tissue crushing;and(3)The lesion borders were marked using ESD techniques before treatment.Complete resection was performed without complications.CONCLUSION Anal canal lesions can be safely and reliably removed when ESD and TAR are used appropriately.

Peat properties of a tropical forest reserve adjacent to a fire-break canal

Tropical peat comprises decomposed dead plant material and acts like a sponge to absorb water,making it fully saturated.However,drought periods dry it readily and increases its vulnerability to fire.Peat fires emit greenhouse gases and particles contributing to haze,and prevention by constructing fire-break canals to reduce fire spread into forest reserves is crucial.This paper aims to determine peat physical and chemical properties near a fire-break canal at different fire frequency areas.Peat sampling was conducted at two forest reserves in Malaysia which represent low fire frequency and high fire frequency areas.The results show that peat properties were not affected by the construction of a fire-break canal,however lignin and cellulose content increased significantly from the distance of the canal in both areas.The study concluded that fire frequency did not significantly influence peat properties except for porosity.The higher fibre content in the high frequency area did not influence moisture content nor the ability to regain moisture.Thus,fire frequency might contribute differently to changes in physical and chemical properties,hence management efforts to construct fire-break canals and restoration efforts should protect peatlands from further degradation.These findings will benefit future management and planning for forest reserves.

Steel bar penetrating cervical spinal canal without neurological injury:A case report

BACKGROUND We report a rare case of cervical spinal canal penetrating trauma and review the relevant literatures.CASE SUMMARY A 58-year-old male patient was admitted to the emergency department with a steel bar penetrating the neck,without signs of neurological deficit.Computed tomography(CT)demonstrated that the steel bar had penetrated the cervical spinal canal at the C6–7 level,causing C6 and C7 vertebral body fracture,C6 left lamina fracture,left facet joint fracture,and penetration of the cervical spinal cord.The steel bar was successfully removed through an open surgical procedure by a multidisciplinary team.During the surgery,we found that the cervical vertebra,cervical spinal canal and cervical spinal cord were all severely injured.Postoperative CT demonstrated severe penetration of the cervical spinal canal but the patient returned to a fully functional level without any neurological deficits.CONCLUSION Even with a serious cervical spinal canal penetrating trauma,the patient could resume normal work and life after appropriate treatment.

The Millennia-Old Canal Takes on a New Look Nihao!China——2024 China's Grand Canal Tourism Overseas Promotion Season

On the occasion of the 10th anniversary of the Grand Canal's application for the World Heritage status in 2024,with the strong support of the Department of International Cooperation of the National Radio and Television Administration and the International Tourism Alliance of Silk Road Cities.

Surgical Management of Lumbar Spinal Canal Stenosis with Instrumentation at the Yaounde Central Hospital: Comparison of Unilateral versus Bilateral Pedicle Screw Fixation Combined with Transforaminal Lumbar Interbody Fusion

Introduction: The choice of adopting unilateral pedicle screw fixation or using bilateral pedicle screw fixation in lumbar spinal stenosis remains controversial. In our context, very few studies have been performed comparing the clinical effectiveness of unilateral versus bilateral fixation in the surgical management of lumbar spinal canal stenosis. Objective: Evaluate the impact on quality of life and clinical efficacy of unilateral spondylodesis compared to bilateral spondylodesis in the surgical management of lumbar spinal canal stenosis at the Yaounde Central Hospital. Methods: This was a retrospective descriptive cross-sectional study for a period of 4 years, from June 2015 to June 2019. It involved all patients operated for lumbar canal stenosis and who underwent spondylodesis or spinal fusion at the neurosurgery department of the Yaounde Central Hospital. Results: A total of 68 participants were recruited during our study period. 32 (47%) of the study population were in the 50 - 60 age group, with a mean age of 56.98 years ranging from 41 to 75 years. Females, housewives and farmers were the most affected. In our study, 72% of patients had unilateral spondylodesis and 28% had bilateral fusion. Preoperatively, 71% of patients had insurmountable pain, refractory to medical treatment. At 3 months postoperatively, 73.7% of patients with bilateral setup had moderate pain compared to 69% of those with unilateral setup. At 6 months postoperatively, 79% of patients with bilateral fusion had mild pain compared to 82% of patients with unilateral setup. At 1 year postoperatively, all patients had mild pain. Preoperatively, 66.2% of patients were unable to walk and 19.1% of patients were bedridden according to the Oswestry score. At 3 months postoperatively, 10.2% of patients with unilateral setup were unable to walk compared to 10.5% of patients with bilateral fixation, while 67.3% of patients with unilateral fixation had moderate disability compared to 52.6% of patients with bilateral fixation. At 6 months postoperatively, 51% of patients with unilateral setup had moderate disability compared to 47.4% of patients with bilateral fixation, while 42.9% of patients with unilateral fixation had mild disability compared to 42.1% of patients with bilateral fixation. At 1 year postoperatively, 81.6% of patients who underwent unilateral fixation had only mild disability compared to 73.7% of patients with bilateral fixation. Conclusion: The assessment of quality of life according to the set-up used shows similar results at 3 months, 6 months and 1 year, with no statistically significant differences. Single-sided pedicle screw fixation combined with transforaminal lumbar interbody fusion or mounting has the advantage of being faster, with less bleeding and is less expensive compared to bilateral fixation.

Results Analysis of Surveys Made to Stakeholders in the Pacific Ports in the Panama Canal:A Study Focused to Improve the Efficiency of Loading/Discharging Operations

This research aims to analyze the communication process between the different participating actors in the port of Balboa,in the Panamanian Pacific.The starting hypothesis begins with the normal operation of the port itself.Considering which strategic actions have potential development and which specific strategic actions are proposed for their improvement,the article begins with a discussion of the nature of ports in Panama and their relationships with the Panama Canal,followed by a literary review of all the effects that climate change may have on navigation on the Panamanian Pacific coast.Next,the implication between the coordination and cooperation between the port,the Panama Canal pilots,and the other actors involved with the arrival and departure of vessels from the port will be analyzed.In a third part,the results of the perception of a significant sample of these actors who were surveyed,which are related to the process,are presented.The document concludes with recommendations on how the Panamanian Pacific port can improve its individual interests through the application of improvements derived from the results of the surveys,for more efficient inter-institutional coordination and cooperation.

Schlemm’s canal结构和功能调控的研究进展及其在青光眼治疗中的应用

Schlemm管(Schlemm’scanal,SC)作为房水流出的主要通道,通过调节房水外排来维持眼内压的平衡,其结构和功能的异常与高眼压及青光眼的发生发展密切相关。对SC的研究有助于阐明房水外排阻滞的发生机制、探索新的途径以增加房水排出,从而为降低眼压和青光眼治疗的新药物开发提供基础。目前,对SC发育和功能的调节机制的认识仍然有限,缺乏针对SC的特异性治疗策略。近年来,关于SC细胞命运决定及其结构发育的细胞学机制逐渐被揭示,功能调控的关键分子靶标也相继被发现,这促进了对SC结构和功能调控的深入理解。此外,作为降眼压药物靶点和针对性手术的创新应用也在不断拓展。文章系统回顾SC的结构与功能研究,总结关键的分子和细胞学调控机制,归纳SC靶向药物和手术疗法的最新进展,为青光眼的临床诊治提供了新的思路。

漕源之变:引沁济运的兴废与明代治河困局

明初,黄河南北摆动不定,人为分引河流众多,为解决大运河缺水问题,全线引河济运,引沁济运亦深受关注。景泰至成化朝,河臣主持引沁工程,实现了运河对沁河水多个方向的引用。弘治至嘉靖朝,治沁以筑堤疏浚为主,引沁工程的实施艰难,成为漕源的备用方案。隆庆至万历朝,围绕引沁入卫产生了一系列争论与矛盾,诸如朝中合流派与分流派治河理念之争、百姓生计与国家治漕之争、沁河上下游利益之争等。在漕运至上和黄河水环境变化的背景下,沁河在嘉靖朝中期以后经历了功能和地位的变化,民生与漕源的矛盾最终在保漕目的下得以调和。引沁济运的兴废反映出明代治河中的内在困局。

Study on Tissue Culture of Leucophyta brownii ‘Canal Rocks Form’

[Objective] This study aimed to establish a tissue culture technology for Leucophyta brownii ‘Canal Rocks Form’. [Method] Leucophyta brownii ‘Canal Rocks Form’ stems with axillary buds were selected as explants in vitro to investigate the effects of different concentrations of 6-BA and NAA on proliferation culture and the effects of IBA, NAA and subculture cycle on rooting culture. [Result] The results showed that Leucophyta brownii ‘Canal Rocks Form’ plantlets need low concentrations of phytohormones and the rooting culture was significantly affected by the subculture cycle; the optimal medium for proliferation culture was MS＋0.5 mg/L 6-BA＋0.05 mg/L NAA＋30 g/L sucrose＋5.5 g/L agar, with a proliferation coefficient of 4.25; the plantlets with a subculture cycle of 28 d were the most suitable for rooting culture, with a rooting rate of 95.9% in 1/2 MS＋0.1 mg/L IBA＋0.05 mg/L NAA＋20 g/L sucrose＋5.5 g/L agar, and the average number and length of roots were 4.69 and 1.68 cm, respectively. [Conclusion] This study laid the foundation for establishing sterile culture system of Leucophyta brownii ‘Canal Rocks Form’.

Comprehensive evaluation of water quality parameters in Tianjin Dagu Dainage Canal

In this paper, some indices of sulfide, organic carbon, oil and heavy metals （copper, lead, zinc, cadmium, mercury, arsenic and chromium） in the sediments from Dagu Dainage Canal at the Bohai Bay during four seasons in 2012 - 2013 are selected, and Water Quality Pollution Index （API） is applied to evaluate water quality indices, aiming for the systematic evaluation of the water quality of Dagu Dainage Canal. The results showed that four stations of D3, D6, D7and D9 for S2 had the type Ⅱand Ⅲ of water; others had the type Ⅰ ; the total level of TOC, TPH, Cu, Pb, Zn, Cd, Hg, As and Cr were type Ⅰ, Ⅳ, Ⅱ, Ⅴ, Ⅱ, Ⅴ, Ⅲ, Vand Ⅴ. Water Quality Pollution Index （API） was 3.28, which illustrated Dagu Dainage Canal was in the state of contamination and the degree of pollution exceeded the standard functional areas.

有限元分析牙髓根尖周病根管治疗中的牙体力学性能

背景:根管治疗后牙髓根尖周病变患牙往往因失去较多健康牙体组织等原因导致抗折强度降低,如何增强牙齿抗折强度一直是临床医生密切关注的问题。有限元分析能直观地展示不同状态下患牙各个部分的受力情况,对牙体结构和材料力学性能等进行综合分析。目的:综述有限元分析在牙髓根尖周病根管治疗中的应用进展,并对未来的发展趋势进行展望。方法:在PubMed、Web of Science数据库和中国知网、万方数据库、维普数据库、中国生物医学文献服务系统中检索使用有限元法分析牙髓根尖周病根管治疗的相关文献,英文检索词为“FEA,finite element analysis,stress analysis,root canal treatment,pulp opening,root canal preparation,root canal filling,restoration”,中文检索词为“有限元分析,应力分析,牙髓根尖周病,根管治疗,开髓,根管预备,根管充填,修复”,最终纳入103篇文献进行综述。结果与结论:有限元分析可以通过构建牙体及周围组织的有限元模型分析牙齿在咀嚼、咬合等过程中的应力分布和变形情况。借助有限元分析,临床研究者能够对牙髓根尖周病根管治疗中不同开髓洞型、根管预备方式、根管充填材料及修复方案等对牙体力学性能的影响进行分析,从而选择出最佳的治疗方案,提高治疗效果和患者预后。有限元分析有助于医生在临床治疗中减少牙体组织的损失,提高治疗效果和患者预后。有限元模型是对实际情况的简化,需结合临床试验进行综合分析。

成人椎管内非典型脉络丛乳头状瘤一例

本文为回顾性研究,遵守《赫尔辛基宣言》,经过内蒙古医科大学附属医院伦理委员会批准,批准文号:KY2024074,受试者在回访时签署了知情同意书。患者女,56岁,因“腰腿部疼痛半年余,加重1月”于2023年9月11日收入内蒙古医科大学附属医院神经外科。

Ecological Design of Flood Discharging Canals in Shijiazhuang City

From the perspective of ecological conservation and satisfaction of people's visual and psychological demands,existing problems in the urban revetment were analyzed,and the connotation of ecological revetment as well as the selection of different ecological revetments according to different types of river ways was discussed.

高声强冲击波作用人耳动态响应特性

为研究冲击波作用下的人耳动态响应特性,设计并开展基于某单兵火箭类武器发射环境的有/无佩戴护听器装置试验研究。在分析发射冲击波特性的基础上,设计制作人耳测试装置模型,形成耳内冲击波防护试验测试方法。通过在射手位置处布设人耳测试装置模型以获取人耳内压力-时间变化曲线,并采用超压传感器测量对比位置处的自由场冲击波压力。利用小波分析法对测到的数据进行分析,对比分析2种发射冲击波安全限值的评价方法。研究结果表明:发射时的高声强冲击波具有不稳定性,超压峰值高,持续时间短,具有多个脉冲;高声强冲击波频带宽,成分复杂,有明显的低频率高声压特性;无护听器装置时耳内压力有所增强;佩戴护听器装置后可大幅度削弱冲击波对人耳的作用,正射手右耳超压峰值削弱95.7%、声压级峰值削弱14.8%;改进后的国家军用标准GJB 2A—1996“常规兵器发射或爆炸时脉冲噪声和冲击波对人员听觉器官损伤的限值”和美军标MIL-STD-1474E“Department of defense design criteria standard noise limits”中AHAAH模型2种方法得到的单日允许射击数范围接近,对佩戴护听器装置后的冲击波测量曲线评估的方法是可行的。研究结果可为单兵火箭类武器发射冲击波测试系统优化及改进提供理论基础和实践指导。

北京温榆河公园鸟类多样性特征与生境优化策略

北京温榆河公园位于北京市第二道绿化隔离地区,是依托北京温榆河−北运河生态廊道建设而成的超大城市级绿色空间,研究其鸟类多样性特征,优化其生境质量对维持北京地区的生物多样性具有重要意义。根据北京温榆河公园2022年1月−2023年12月的鸟类多样性调查数据,详细识别公园内鸟类的群落结构并划分不同的鸟类取食集团,分析不同季节的鸟类多样性时空特征与多样性热点区域;根据遥感解译与植被多样性调查结果对研究区域的生境类型进行划分,针对具有不同鸟类群落特征的生境类型提出具体的优化方案。结果表明:①在北京温榆河公园共调查到鸟类174种,隶属于19目51科,其中,有国家Ⅰ级重点保护物种4种,国家Ⅱ级重点保护物种21种。②北京温榆河公园鸟类的α-多样性在春季最高,温榆河主河道具有最高的鸟类多度和多样性指数。③北京温榆河公园可划分为生境类型Ⅰ(滨水湿地+乔灌林地)、生境类型Ⅱ(密林地)、生境类型Ⅲ(滨水湿地+疏林地)3种生境组合。根据不同生境中的鸟类群落特征差异有针对性地提出生境优化策略,建议生境类型Ⅰ在维护湿地生境的同时提高陆生鸟类栖息地的质量;生境类型Ⅱ增加常绿树种、小乔木、食源灌木和乡土草本植物的种植密度,减少对地被植物的收割干扰与枯落物清除,提高微景观异质性;生境类型Ⅲ增加配置具有速生特性的鸟类食源树种,适度提高乔灌层的高度、盖度和丰富度。

平陆运河生态廊道建设研究

随着内河水运的快速发展,大型人工运河的研究及建设持续推进,对建设全过程的生态绿色要求也日益增加。基于平陆运河工程特点及生态环境重点问题,进行运河生态廊道的构建及布局研究,通过划分空中、水下、陆上、河岸廊道,提出动物通道、生态涵养区等生态设施节点设计,以增加运河全线不同生态斑块的连通性。通过总结平陆运河生态廊道的建设布局,以及生态节点设施布置、设计重点,为其他跨流域水系连通人工运河的生态建设提供借鉴与参考。

论杭州与京杭大运河城河相依关系的独特性

在中国大运河流经的35个城市中,城河关系各有不同,杭州城河相依关系具有其独特性。该文通过对杭州运河历史发展过程的梳理,分析了运河穿城而过的原因,进而论述了运河对城市发展的影响,试图深入认识杭州城河相依的特点。

乡村河道环境生态治理研究

乡村河道景观规划和生态建设是城乡环境建设的重要组成部分,合理的更新改造建设可以使乡村河道发挥生态、景观、灌溉等综合功能。本文对万金渠辛庄村乡村河道现状及存在问题进行分析与研究,对比万金渠城区段的成功改造经验,着力探讨如何运用“海绵城市”工程措施进行乡村河道改造,最终系统构建城乡一体化生态河道景观。

根管治疗术治疗牙髓炎的疗效及疗效的影响因素分析

目的评价根管治疗术(RCT)治疗牙髓炎的疗效,分析影响疗效的因素,为临床提供参考依据。方法选取2021年1月—12月淄博市第四人民医院完成根管治疗的168例牙髓炎患者,将治疗成功的148例患者纳入成功组,20例治疗失败的患者纳入失败组。比较两组恰填率、欠填率、超填率及随访2年的成功率、失败率。采用Logistics回归分析影响根管治疗效果的因素。结果RCT后X线片评价恰填率90.48%,欠填率5.36%,超填率4.17%。所有患者均随访2年,成功率88.10%,失败率11.90%。成功组患牙牙位为磨牙、有隐裂、根管及根尖状态异常、恰填的构成比例分别为55.41%、3.38%、12.84%、91.89%,对照组分别为75.00%、20.00%、40.00%、80.00%,差异有统计学意义(P<0.05)。两组患牙牙位、有无隐裂、根管及根尖状态和根充质量比较,差异有统计学意义(P<0.05)。根充质量欠填和牙位为磨牙是影响RCT疗效的主要因素(OR=1.826、1.933,P<0.05)。结论根管治疗术是牙髓炎治疗的有效方法,根充质量欠填、牙位为磨牙是影响根管治疗术疗效的主要因素。