Necking of Q&P Steel during Uniaxial Tensile Test with the Aid of DIC Technique

A lot of research has been focused on the necking process during the plastic deformation of sheet metals, but the localized necking is rarely distinguished form diffused necking by experiments, due to the limit of measurement equipment and method. Quenching and Partitioning (Q&P) steel is a 3rd generation advanced high strength steel (AHSS). Its good combination of high strength and ductility ensures potential application in automobile industry. Uniaxial tensile tests of QP980 steel sheet at five strain rates are performed to investigate the necking process and the effect of strain rate on necking behavior of Q&P steel. Digital image correlation (DIC) method is applied during tensile tests, and evolutions of major strain, minor strain and normal strain distributions along gauge section of the tensile specimens are obtained. The diffused and localized necking strains are determined according to SWIFT necking theory and HILL necking theory respectively. The test results indicate that with the increasing of strain rate in the investigated range, the diffused necking strain decreases from 0.152 to 0.120 and localized necking strain decreases from 0.245 to 0.137. Meanwhile, the difference of the two strains decreases form 0.096 to 0.017. Thus it can be concluded that strain rate has an influence on both necking strains during the deformation of QP980 steel sheet. Diffused and localized necking strains are determined by uniaxial tensile tests with the aid of DIC technique and the effect of strain rate on necking strains is evaluated.

Mechanism of necking defect of 6082 aluminium alloy rolled by cross-wedge rolling method based on material thermal properties

Necking defects have long troubled the application of cross-wedge rolling technology in aluminium alloy shaft parts.To accurately predict necking defects,new judgement conditions are established based on the thermal performance of 6082 aluminium alloy.The limit-sectional shrinkage without necking defects is achieved by combining theoretical calculation and finite-element model analysis,which couples heat transfer and deformation.In this paper,a 6082 aluminium alloy extruded rod with a 40 mm diameter rolled at a preheated temperature of 500℃and a rolling angular velocity of 1 rad/s is taken as an example.The simulation and experimental results show that necking defects do not occur on the rolled pieces if the sectional shrinkage is below the limit-sectional shrinkage but will occur when the sectional shrinkage is above it.The results prove that the prediction model of necking defects in cross-wedge rolling of 6082 aluminum alloy is feasible,and this research provides a theoretical basis for the qualified aluminum alloy shafts produced by the cross-wedge rolling.

MECHANISMS OF LOCALIZED NECKING DEFORMATION OF SHEET METALS

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Numerical simulation of spinning deformation of thin-walled tube in necking process

The spinning deformation of thin walled tube in necking process is simulated with a dynamic explicit FEM program,LS DYNA3D and the distributions of Cauchy strains and thickness are analyzed through time history to achieve a good understanding of the deformation in necking process by spinning and the numerical simulation results are in good agreement with the test results.

Necking Point in PET High-speed Fiber Spinning

Cross-over method is established to predict necking point for PET high- speed fiber spinning. Even slowly crystallizing polymers such as PET can crystallize on the spinline at sufficiently high spinning speed. The development of rtmning velocity, temperature, crystallinity and theological force is investigated for the take-up velocity over a range of 6 000 - 10 000 m/min. The position of necking point, temperature rise and abrupt increase of crystallinity move closer to the spinneret with the increase of take-up velocity,

Theoretical and Numerical Comparison of Limit Point Bifurcation and Maximum Force Criteria. Application to the Prediction of Diffuse Necking

A large number of criteria has been developed to predict material instabilities, but their choice is limited by the lack of existing comparison of their theoretical basis and application domains. To overcome this limitation, a theoretical and numerical comparison of two major models used to predict diffuse necking is present in this paper. Limit Point Bifurcation criterion is first introduced. An original formulation of the Maximum Force Criterion (MFC), taking into account the effects of damage and isotropic and kinematic hardenings, is then proposed. Strong connections are shown between them by comparing their theoretical basis. Numerical Forming Limit Diagrams at diffuse necking obtained with these criteria for different metallic materials are given. They illustrate the theoretical link and similar predictions are shown for both models.

基于改进YOLO v8s的小麦小穗赤霉病检测研究

为实现大田复杂背景下小麦小穗赤霉病快速准确识别,构建了包含冬小麦开花期、灌浆期和成熟期3个生育期共计640幅的小麦赤霉病图像数据集,并提出一种基于改进YOLO v8s的小麦小穗赤霉病识别方法。首先,利用全维动态卷积ODConv替换主干网络中的标准Conv,提高网络对目标区域特征的提取;然后,在Neck网络使用改进Efficient RepGFPN特征融合网络实现低层特征与高层语义信息的融合,使模型能够提取更丰富的特征信息;最后,采用EIoU损失函数替换CIoU损失函数,加快模型收敛速度,进一步提高模型准确率,实现对小麦小穗赤霉病的快速、准确识别。在自建的数据集上进行模型验证,结果表明,改进模型(OCE-YOLO v8s)对小麦小穗赤霉病的检测精度达到98.3%,相比原模型提高2个百分点;与Faster R-CNN、CenterNet、YOLO v5s、YOLO v6s、YOLO v7模型相比分别提高36、25.7、2.1、2.6、3.9个百分点。提出的OCE-YOLO v8s模型能有效实现小麦小穗赤霉病精确检测,可为大田环境下农作物病虫害实时监测提供参考。

颈部挫伤并发甲状腺上动脉破裂致咽喉后壁血肿1例

1临床资料患者,男,65岁,因“颈部闭合性损伤1 h”急诊收治入院,就诊时呈渐近性呼吸困难加重,伴有咽痛明显,无明显声嘶发作。查体:颈部肿胀明显,皮下有少许淤血样改变,颈部皮肤完整。3~4度阻塞性呼吸困难,不能平卧位。相关科室除外颅脑、胸腹并发伤后,急诊坐位下行气管切开术,术后呼吸有改善,但效果不明显。术前颈动脉血管造影发现左侧甲状腺上动脉破裂(图1A),颈部CT示血肿上至第2颈椎水平,下至第1胸椎水平(图1B、1C),咽喉后壁巨大血肿约500 ml,术前介入科行血管栓塞术。

基于YOLOv8n改进的织物疵点检测算法

为了解决织物疵点检测中小目标疵点难以检测的问题,提出了一种基于改进YOLOv8n算法的织物疵点检测系统。首先,在特征融合部分,采用了兼顾速度和精度的GSConv替代原有的卷积核,并引入了Slim⁃neck特征融合模块,使每个特征层能够同时考虑深层特征的语义信息和浅层特征的细节信息,提高了对小目标的特征响应,同时简化了模型并降低了计算复杂度。其次,设计了用于检测小疵点目标的检测层P2,增强了模型对小疵点目标的检测能力,使其更适用于织物疵点检测任务。最后,采用指数滑动样本加权函数(EMA⁃SlideLoss)替代了交叉熵损失函数,以增强模型的类别分类能力,提高训练的稳定性。试验结果表明:在检测20类疵点时,相较于YOLOv8n模型,该研究方法在mAP@0.5方面提高了0.142,同时实现了47.4帧/s的检测速度。改进的YOLOv8n模型对网络的性能提升是有效的。

准确影像定位在颈部食管腔外异物取出术的应用

目的分析颈部食管腔外异物的临床特点及准确影像定位在其诊断和治疗中的应用。方法回顾性分析2017年10月~2024年3月梅州市人民医院耳鼻咽喉科收治的10例颈部食管腔外异物患者,对颈胸部CT行多平面重建(multiplanar reconstruction,MPR),从横断位、冠状位、矢状位判断异物位置,选择合适的手术入路。结果10例颈部食管腔外异物,2例金属和1例木质异物为外伤进入颈部,7例鱼骨为误吞鱼骨迁移颈部。术前影像定位提示异物在环状软骨和甲状软骨周3例,甲状腺内1例,相对应颈椎周2例,胸锁乳突肌周2例,舌骨周2例。支撑喉镜下取出2例,经颈部切开入路取出7例,1例未取出转上级医院治疗。术中彩超协助定位3例。所有患者随访至今均痊愈。结论准确影像定位可为颈部食管腔外异物选择合适手术入路提供依据,术中若异物寻找困难,可借助术中彩超精确定位异物,为成功取出异物提供有力保障。

原发性颈淋巴结结核诊治分析

目的探讨原发性颈淋巴结结核的临床特征、确诊方式及诊疗方案。方法回顾性分析宁波市医疗中心李惠利医院确诊的39例原发性颈淋巴结结核患者临床资料,总结其临床特点、治疗方法及随访情况。结果所有患者均以颈部无痛性质韧肿块为首发症状,肿块多位于颈部Ⅲ、Ⅳ、Ⅴ区,部分位于Ⅰ、Ⅱ区,均完善CT、MRI或B超等检查。根据影像学检查和临床经验,21例患者行结核菌素试验(PPD)或结核感染T细胞斑点试验(T-SPOT),其中2例PPD阳性,13例T-SPOT阳性,15例均经穿刺病理结果确诊,6例经手术病理确诊;1例经细针穿刺细菌培养发现结核杆菌确诊;17例影像学考虑肿瘤性病变,经颈淋巴结清扫或肿块部分切除术后病理确诊结核。39例患者均予标准抗结核治疗半年,随访1年未见复发。结论原发性颈淋巴结结核缺乏特异性症状,初步诊断可借助T-SPOT检查,确诊仍需结核杆菌培养阳性、穿刺细胞学或组织病理结果,治疗应采用世界卫生组织(WHO)推荐的6个月治疗方案,当伴有脓肿、窦道或溃疡型结核时,应结合手术治疗,可有效缩短术后抗结核治疗时间、减少药物用量及不良反应。

Complication rates after direct anterior vs posterior approach for hip hemiarthroplasty in elderly individuals with femoral neck fractures

BACKGROUND Dislocation rates after hemiarthroplasty reportedly vary from 1%to 17%.This serious complication is associated with increased morbidity and mortality rates.Approaches to this surgery are still debated,with no consensus regarding the superiority of any single approach.AIM To compare early postoperative complications after implementing the direct anterior and posterior approaches(PL)for hip hemiarthroplasty after femoral neck fractures.METHODS This is a comparative,retrospective,single-center cohort study conducted at a university hospital.Between March 2008 and December 2018,273 patients(a total of 280 hips)underwent bipolar hemiarthroplasties(n=280)for displaced femoral neck fractures using either the PL(n=171)or the minimally invasive direct anterior approach(DAA)(n=109).The choice of approach was related to the surgeons’practices;the implant types were similar and unrelated to the approach.Dislocation rates and other complications were reviewed after a minimum followup of 6 mo.RESULTS Both treatment groups had similarly aged patients(mean age:82 years),sex ratios,patient body mass indexes,and patient comorbidities.Surgical data(surgery delay time,operative time,and blood loss volume)did not differ significantly between the groups.The 30 d mortality rate was higher in the PL group(9.9%)than in the DAA group(3.7%),but the difference was not statistically significant(P=0.052).Among the one-month survivors,a significantly higher rate of dislocation was observed in the PL group(14/154;9.1%)than in the DAA group(0/105;0%)(P=0.002).Of the 14 patients with dislocation,8 underwent revision surgery for recurrent instability(posterior group),and one of them had 2 additional procedures due to a deep infection.The rate of other complications(e.g.,perioperative and early postoperative periprosthetic fractures and infection-related complications)did not differ significantly between the groups.CONCLUSION These findings suggest that the DAA to bipolar hemiarthroplasty for patients with femoral neck fractures is associated with a lower dislocation rate(<1%)than the PL.

Artificial intelligence-driven radiomics study in cancer:the role of feature engineering and modeling

Modern medicine is reliant on various medical imaging technologies for non-invasively observing patients’anatomy.However,the interpretation of medical images can be highly subjective and dependent on the expertise of clinicians.Moreover,some potentially useful quantitative information in medical images,especially that which is not visible to the naked eye,is often ignored during clinical practice.In contrast,radiomics performs high-throughput feature extraction from medical images,which enables quantitative analysis of medical images and prediction of various clinical endpoints.Studies have reported that radiomics exhibits promising performance in diagnosis and predicting treatment responses and prognosis,demonstrating its potential to be a non-invasive auxiliary tool for personalized medicine.However,radiomics remains in a developmental phase as numerous technical challenges have yet to be solved,especially in feature engineering and statistical modeling.In this review,we introduce the current utility of radiomics by summarizing research on its application in the diagnosis,prognosis,and prediction of treatment responses in patients with cancer.We focus on machine learning approaches,for feature extraction and selection during feature engineering and for imbalanced datasets and multi-modality fusion during statistical modeling.Furthermore,we introduce the stability,reproducibility,and interpretability of features,and the generalizability and interpretability of models.Finally,we offer possible solutions to current challenges in radiomics research.

Laryngopharyngeal reflux disease:Updated examination of mechanisms,pathophysiology,treatment,and association with gastroesophageal reflux disease

Laryngopharyngeal reflux disease(LPRD)is an inflammatory condition in the laryngopharynx and upper aerodigestive tract mucosa caused by reflux of stomach contents beyond the esophagus.LPRD commonly presents with symptoms such as hoarseness,cough,sore throat,a feeling of throat obstruction,excessive throat mucus.This complex condition is thought to involve both reflux and reflex mechanisms,but a clear understanding of its molecular mechanisms is still lacking.Currently,there is no standardized diagnosis or treatment protocol.Therapeutic strategies for LPRD mainly include lifestyle modifications,proton pump inhibitors and endoscopic surgery.This paper seeks to provide a comprehensive overview of the existing literature regarding the mechanisms,pathophysiology and treatment of LPRD.We also provide an in-depth exploration of the association between LPRD and gastroesophageal reflux disease.

甲状腺乳头状癌超声图像表现在预测颈部Ⅵ区淋巴结转移危险度的临床价值

目的 分析甲状腺乳头状癌(PTC)超声图像表现在预测颈部Ⅵ区淋巴结转移(lymph node metastasis in the cervicalregion Ⅵ,CLNM-Ⅵ)危险度的临床价值。方法 选取2022年4月~2023年6月在河北省沧州中西医结合医院接受手术治疗并经病理证实的350例PTC患者,根据术后病理结果,将患者分为CLNM-Ⅵ组和非CLNM-Ⅵ组。收集并对比两组术前超声图像表现及临床病理特征,应用Logistic回归分析PTC患者CLNM-Ⅵ危险因素,受试者工作特征(ROC)曲线分析PTC超声图像表现对CLNM-Ⅵ的预测价值。结果 单因素分析显示,CLNM-Ⅵ组男性、实性或囊实性、年龄≤45岁、低回声、甲状腺背景正常、点状强回声的构成比均大于非CLNM-Ⅵ组(P均<0.05)。Logistic回归分析显示,男性、实性或囊实性、年龄≤45岁、低回声、甲状腺背景正常、病灶内可见点状强回声是CLNM-Ⅵ的独立危险因素(P均<0.05);进一步经ROC曲线分析显示,以上预测CLNM-Ⅵ的AUC分别为0.565、0.580、0.529、0.585、0.582、0.582,联合预测AUC为0.708。结论PTC超声图像表现在CLNM-Ⅵ风险评估中具有重要意义,可为PTC的预后判断提供一定的参考依据。

Overview on the Prediction Models for Sheet Metal Forming Failure:Necking and Ductile Fracture

The formability of the material determines the amount of available deformation before failure and thus is important for the production of various structural components in industries. The workability of materiMs is commonly evaluated by different forms of failure mod- els during sheet metal forming （SMF） processes. In order to provide a whole picture about the prediction models for SMF failure, necking-related formability and ductile fracture-related forma- bility studies in SMF processes are systematically summarized, the applicability and limitation of each model are highlighted, and the link between forming limit diagram and ductile fracture criterion is pointed out, Conclusions about some critical issues on failure in SMF are made.

On the tension necking of copper single crystal specimen under slip deformation mechanism

The tension necking of FCC copper single crystal specimen with a square cross section was analyzed under the slip deformation mechanism. The actual clamp manner of the specimen was modeled by setting correlative boundary condition,and the small angle deflection between tension loading axis and crystallography axis [100] was taken into account. The finite deformation numerical analysis of three-dimensional necking deformation for the specimen was performed by apply-ing crystal plasticity theory associated with a numerical algorithm suggested by the first author. According to the comparison with experimental observation,the fact was confirmed that the numerical results could describe the loading elongation curve of the copper single crystal specimen under large strain tension reasonably,and the method could be used to investigate the necking characteristic in neck shape and the effect due to the small angle deflection. Further,the investigation into the influence of specimen cross-section shape on necking was also performed;the results on mechanical response and neck profile evolution obtained through modeling of cylindrical specimen were compared with those obtained with square cross-section specimen.

Engineering The Neck Hinge Reshapes The Processive Movement of Kinesin-3

Objective In kinesin-3,the neck coil correlates with the following segments to form an extended neck that contains a characteristic hinge diverse from a proline in KIF13B to a long flexible linker in KIF1A.The function of this neck hinge for controlling processive movement,however,remains unclear.Methods We made a series of modifications to the neck hinges of KIF13B and KIF1A and tested their movement using a single-molecule motility assay.Results In KIF13B,the insertion of flexible residues before or after the proline differentially impacts the processivity or velocity,while the removal of this proline increases the both.In KIF1A,the deletion of entire flexible neck hinge merely enhances the processivity.The engineering of these hinge-truncated necks of kinesin-3 into kinesin-1 similarly boosts the processive movement of kinesin-1.Conclusion The neck hinge in kinesin-3 controls its processive movement and proper modifications tune the motor motility,which provides a novel strategy to reshape the processive movement of kinesin motors.

Summarizing the evidence for robotic-assisted bladder neck reconstruction: Systematic review of patency and incontinence outcomes

Objective:Bladder neck contracture and vesicourethral anastomotic stenosis are difficult to manage endoscopically,and open repair is associated with high rates of incontinence.In recent years,there have been increasing reports of robotic-assisted bladder neck reconstruction in the literature.However,existing studies are small,heterogeneous case series.The objective of this study was to perform a systematic review of robotic-assisted bladder neck reconstruction to better evaluate patency and incontinence outcomes.Methods:We performed a systematic review of PubMed from first available date to May 2023 for all studies evaluating robotic-assisted reconstructive surgery of the bladder neck in adult men.Articles in non-English,author replies,editorials,pediatric-based studies,and reviews were excluded.Outcomes of interest were patency and incontinence rates,which were pooled when appropriate.Results:After identifying 158 articles on initial search,we included only ten studies that fit all aforementioned criteria for robotic-assisted bladder neck reconstruction.All were case series published from March 2018 to March 2022 ranging from six to 32 men,with the median follow-up of 5e23 months.A total of 119 patients were included in our analysis.A variety of etiologies and surgical techniques were described.Patency rates ranged from 50%to 100%,and pooled patency was 80%(95/119).De novo incontinence rates ranged from 0%to 33%,and pooled incontinence was 17%(8/47).Our findings were limited by small sample sizes,relatively short follow-ups,and heterogeneity between studies.

Fibroblast activation protein (FAP) as a prognostic biomarker in multiple tumors and its therapeutic potential in head and neck squamous cell carcinoma

Background:Fibroblast activation protein(FAP),a cell surface serine protease,plays roles in tumor invasion and immune regulation.However,there is currently no pan-cancer analysis of FAP.Objective:We aimed to assess the pan-cancer expression profile of FAP,its molecular function,and its potential role in head and neck squamous cell carcinoma(HNSC).Methods:We analyzed gene expression,survival status,immune infiltration,and molecular functional pathways of FAP in The Cancer Genome Atlas(TCGA)and Genotype Tissue Expression(GTEx)tumors.Furthermore,to elucidate the role of FAP in HNSC,we performed proliferation,migration,and invasion assays post-FAP overexpression or knock-down.Results:FAP expression was elevated in nine tumor types and was associated with poor survival in eight of them.In the context of immune infiltration,FAP expression negatively correlated with CD8+T-cell infiltration infive tumor types and positively with regulatory T-cell infiltration in four tumor types.Our enrichment analysis highlighted FAP’s involvement in the PI3K-Akt signaling pathway.In HNSC cells,FAP overexpression activated the PI3K-Akt pathway,promoting tumor proliferation,migration,and invasion.Conversely,FAP knockdown showed inhibitory effects.Conclusion:Our study unveils the association of FAP with poor tumor prognosis across multiple cancers and highlights its potential as a therapeutic target in HNSC.