The Performance of Concrete Made with Secondary Products—Recycled Coarse Aggregates,Recycled Cement Mortar,and Fly Ash–Slag Mix

The properties of cement concrete using waste materials—namely, recycled cement mortar, fly ash–slag, and recycled concrete aggregate—are presented. A treatment process for waste materials is proposed. Two research experiments were conducted. In the first, concretes were made with fly ash–slag mix (FAS) and recycled cement mortar (RCM) as additions. The most favorable content of the concrete additive in the form of RCM and FAS was determined experimentally, and their influence on the physical and mechanical properties of concrete was established. For this purpose, 10 test series were carried out according to the experimental plan. In the second study, concretes containing FAS–RCM and recycled concrete aggregate (RCA) as a 30% replacement of natural aggregate (NA) were prepared. The compressive strength, frost resistance, water absorption, volume density, thermal conductivity, and microstructure were researched. The test results show that the addition of FAS–RCM and RCA can produce composites with better physical and mechanical properties compared with concrete made only of natural raw materials and cement. The detailed results show that FAS–RCM can be a valuable substitute for cement and RCA as a replacement for natural aggregates. Compared with traditional cement concretes, concretes made of FAS, RCM, and RCA are characterized by a higher compressive strength: 7% higher in the case of 30% replacement of NA by RCA with the additional use of the innovative FAS–RCM additive as 30% of the cement mass.     

Variability in the Spatial Structure of the Central Loop in Cobra Cytotoxins Revealed by X-ray Analysis and Molecular Modeling

Cobra cytotoxins (CTs) belong to the three-fingered protein family and possess membrane activity. Here, we studied cytotoxin 13 from Naja naja cobra venom (CT13Nn). For the first time, a spatial model of CT13Nn with both “water” and “membrane” conformations of the central loop (loop-2) were determined by X-ray crystallography. The “water” conformation of the loop was frequently observed. It was similar to the structure of loop-2 of numerous CTs, determined by either NMR spectroscopy in aqueous solution, or the X-ray method. The “membrane” conformation is rare one and, to date has only been observed by NMR for a single cytotoxin 1 from N. oxiana (CT1No) in detergent micelle. Both CT13Nn and CT1No are S-type CTs. Membrane-binding of these CTs probably involves an additional step—the conformational transformation of the loop-2. To confirm this suggestion, we conducted molecular dynamics simulations of both CT1No and CT13Nn in the Highly Mimetic Membrane Model of palmitoiloleoylphosphatidylglycerol, starting with their “water” NMR models. We found that the both toxins transform their “water” conformation of loop-2 into the “membrane” one during the insertion process. This supports the hypothesis that the S-type CTs, unlike their P-type counterparts, require conformational adaptation of loop-2 during interaction with lipid membranes.     

X-ray Imaging of Alloy Solidification: Crystal Formation,Growth, Instability and Defects

Synchrotron and laboratory-based X-ray imaging techniques have been increasingly used for in situ investigations of alloy solidification and other metal processes. Several reviews have been published in recent years that have focused on the development of in situ X-ray imaging techniques for metal solidification studies. Instead, this work provides a comprehensive review of knowledge provided by in situ X-ray imaging for improved understanding of solidification theories and emerging metal processing technologies. We first review insights related to crystal nucleation and growth mechanisms gained by in situ X-ray imaging, including solute suppressed nucleation theory of α-Al and intermetallic compound crystals, dendritic growth of α-Al and the twin plane re-entrant growth mechanism of faceted Fe-rich intermetallics. Second, we discuss the contribution of in situ X-ray studies in understanding microstructural instability, including dendrite fragmentation induced by solute-driven, dendrite root re-melting, instability of a planar solid/liquid interface, the cellular-to-dendritic transition and the columnar-to-equiaxed transition. Third, we review investigations of defect formation mechanisms during near-equilibrium solidification, including porosity and hot tear formation, and the associated liquid metal flow. Then, we discuss how X-ray imaging is being applied to the understanding and development of emerging metal processes that operate further from equilibrium, such as additive manufacturing. Finally, the outlook for future research opportunities and challenges is presented.     

儿童肺结核45例临床特点及诊断分析

目的 分析儿童肺结核的临床特点,为提高儿童肺结核的诊治水平提供依据。方法 回顾性分析45例肺结核患儿的一般资料、实验室检查以及影像学检查结果,比较并分析胸部CT与胸X线片检查结果,并查阅纤维支气管镜检查、治疗支气管内膜结核情况。结果 45例患儿中男28例,女17例。明确接种卡介苗者42例（93.3%）。有明确近期活动性肺结核接触史者11例（24.4%）,既往家庭成员有结核病史者33例（73.3%）。单纯肺结核者37例（82.2%）,合并肺外结核者以结核性胸膜炎多见。常见症状为发热、咳嗽、喘息以及结核中毒症状。儿童肺结核以不同形式起病,以支气管炎和肺炎起病29例（64.4%）,以支气管哮喘起病3例（6.7%）,以慢性咳嗽起病5例（11.1%）,以发热待查起病6例（13.3%）,手术创伤后起病2例（4.4%）。结核菌素纯化蛋白衍生物试验中度以上阳性38例（84.4%）。胸部CT比胸X线片能更好地发现病变。45例中42例进行了纤维支气管镜检查,发现支气管内膜结核13例（31.0%）,予冷冻以及利奈唑胺灌洗治疗,2～3次后支气管内壁变光滑。结论 胸部CT的诊断价值优于胸X线片;纤维支气管镜下予...     

Imaging characteristics of esophageal cancer in multi-slice spiral CT and barium meal radiography and their early diagnostic value

BackgroundTo explore the imaging characteristics of esophageal cancer in multi-slice spiral CT (MSCT) and barium meal radiography and to analyze the value of the two examinations alone or in combination for cancer staging diagnosis.MethodsThe clinical data of 87 patients with esophageal cancer admitted to our hospital from June 2018 to June 2020 were retrospectively analyzed. According to the different examination methods, they were divided into a barium meal group (n=28 cases, X-ray barium meal radiography), an MSCT group (n=29 cases, MSCT examination), and a combined group (n=30 cases, barium meal + MSCT). The imaging characteristics from the barium meal radiography and MSCT alone versus their combined results were compared with the pathological examination results to analyze their accuracy in diagnosing esophageal cancer staging.ResultsOf the 87 cases, the esophageal cancer lesion sites were as follows: 23 cervical cases, 20 upper thoracic cases, 21 middle thoracic cases, and 23 lower thoracic cases. The X-ray barium meal examination of esophageal mucosa showed irregular filling of the esophagus. The esophageal wall was stiff or jagged, the lumen was narrow, and it was difficult for the barium to pass, the mucosa was discontinuous. The CT scan showed irregular thickening of the esophageal wall, eccentric and concentric stenosis of the esophageal cavity, and the upper part of the esophagus showed different degrees of expansion. The trachea and bronchi were invaded, deformed, and displaced under compression. The diagnostic staging results of the barium meal group and MSCT group were inconsistent with the pathological results (Kappa =0.105, 0.112; P>0.05). The diagnostic staging results of the combined group were in good agreement with the pathological results (Kappa =0.769). In addition, the accuracy of the combined group in the diagnosis of stage III–IV esophageal cancer among the three groups was significantly higher than that of the barium meal group and MSCT group alone (P<0.05).ConclusionsMSCT and barium meal radiography clearly display the imaging features of esophageal cancer and can provide reliable imaging evidence for preoperative diagnosis; the combination of both measures can effectively improve the accuracy of early diagnosis for esophageal cancer.     

螺旋CT对下咽癌的诊断价值

[目的]探讨螺旋CT对下咽癌的诊断价值.[方法]将30 例下咽癌行螺旋CT扫描,并将CT诊断与手术病理结果进行对照分析.[结果]螺旋CT判断下咽癌侵犯声门旁间隙、会厌前间隙、甲状软骨、环状软骨、杓状软骨、杓会厌皱襞及声带的准确率分别为93.3%、100%、71.4%、100%、50.0%、91.7%及60.0%,判断下咽癌侵犯喉结构总的准确率为85.5%.[结论]螺旋CT对下咽癌的诊断及鉴别诊断有重要价值.     

口服甘露醇CT小肠造影对小肠肿瘤的诊断价值

[目的]评价口服大剂量5%等渗甘露醇螺旋CT小肠造影(spiral CT enterography,SCTE)在小肠肿瘤诊断中的价值.[方法]36例小肠肿瘤患者每人口服约1 000～1 500 mL 5%等渗甘露醇后,肌注20 mg山莨菪碱注射液,10～15 min后行螺旋CT三维扫描,分析不同小肠肿瘤的SCTE表现,并比较42例传统CT扫描与SCTE的诊断结果.[结果]36例SCTE患者除2例回盲部充盈欠佳外,余病例十二指肠、空肠及回肠肠腔充盈良好,对肿瘤的显示、衬托满意.SCTE检查与临床诊断符合率为94.4%(34/36),高于传统CT扫描78.57%(33/42)(χ2=4.03,P＜0.05).[结论]SCTE是一种简便、安全、非侵袭性、有效评价小肠肿瘤的方法,能明显提高肿瘤的检出率.     

脊髓栓系综合征的影像学评价

目的 探讨脊髓栓系综合征的CT、MRI表现以及在该病诊断中的价值.方法 分析经手术病理证实的45例脊髓栓系综合征患者的CT、MRI资料,再与手术病理对照.结果 45例脊髓栓系综合征中,CT诊断脊髓低位39例,漏诊6例.脊柱裂41例,椎体畸形脊柱侧弯7例,脊髓纵裂3例,其中骨性分隔1例,诊断准确率100%.MRI诊断脊髓低位45例,脊柱裂39例,漏诊6例,椎体畸形脊柱侧弯7例,脊髓纵裂3例,对1例骨性分隔显示不清.结论 脊髓栓系综合征伴发复杂骨骼畸形的患者,MRI结合CT诊断,对患者一次性手术能提供更加详细的信息,提高诊断准确性,减少漏诊.     

直背综合征X线诊断和分级方法的探讨

目的 研究直背综合征X线表现和特点,探讨X线诊断标准,提出X线分级方法.方法 本组91例中男52例,女39例,年龄16-87岁,平均34.86岁,全部病例摄取标准胸部正位及左侧位片,测量胸廓前后径(APDb)和横径(TTDb),计算胸前后径和横径之比率.结果 本组胸廓前后径和横径比最大值38%,最小值25%;轻度29例,中度36例,重度26例.结论 APDb/TTDb比值≤38%可诊断直背综合征.提出分级标准:轻度,比值38-36%;中度,比值35-33%;重度,比值32%以下.     

急性肠缺血的MSCT诊断价值探讨

目的 评价MSCT对急性肠缺血(AMI)的诊断价值.方法 回顾性分析5例AMI患者的平扫、动脉期、门静脉期和MSCT肠系膜血管成像(MSCTA)图像,描述AMI的肠系膜血管及其相关病变MSCT的表现特点.结果 5个病例中,1例肠系膜血管显示正常.肠系膜上动脉(SMA)梗塞2例,其中1例断面图像表现为SMA起始端以远血管腔内无对比剂充盈,MSCTA示SMA起始端以远未显影;另1例断面图像SMA未见明显异常,MSCTA显示SMA近端局限性狭窄,血管壁明显增厚.肠系膜上静脉梗塞(SMV)2例,其中1例SMV完全闭塞,管腔内无对比剂充盈,MSCTA示SMV和门静脉均未显影;另1例SMV内见充盈缺损影,MSCTA示SMV内见条状低密度影.5例均见小肠病变肠管壁明显增厚、肿胀,肠管积液扩张及腹水,2例见肠系膜水肿,2例并肠壁积气.结论 MSCT能准确显示AMI的肠系膜血管及相关病变情况,是AMI的理想检查方法.