Stabilization of positive coupled differential‐difference equations with unbounded time‐varying delays

This paper researches the static output‐feedback stabilization of single‐input single‐output (SISO) positive coupled differential‐difference equations (CDDEs) with unbounded time‐varying delays. First, a necessary and sufficient condition is provided for the positivity and asymptotical stability of CDDEs with unbounded time‐varying delays. For this type of system, based on the constructed estimates of its solution, a necessary and sufficient condition on asymptotical stability is provided. Then, based on this criterion, for CDDEs with unbounded time‐varying delays, a kind of static output‐feedback controller is designed to ensure the positivity and asymptotical stability of the corresponding closed‐loop systems. It is also worth pointing out that the controller is designed by the linear programming method without parameterization technique. This design approach can also be applied to the static state feedback stabilization problem of CDDEs with unbounded time‐varying delays. Finally, two illustrative examples are given to show the effectiveness of our results.     

Primary malignant melanoma of the bladder

Primary malignant melanomma of bladder is extremely rare: 18 cases are reported to date. An 82 year-old man underwent trans-urethral resection of bladder for a bleeding tumor of the posterior wall. Histological diagnosis was melanoma of the bladder. There was no history of previous or regressed cutaneous malignant melanoma. Margins of the bladder lesion contained atypical melanocytes similar to those commonly seen in the periphery of primary mucous membrane lesions. Clinical studies and radiological examinations were negative for other primary site of melanoma. The patient had a bladder recurrence that was consistent with primary tumor and died of widespread disease 9 months after diagnosis.     

Nash equilibrium solutions of tracking game for bilinear systems with exponential reference signals

In this paper, we consider the problem of Nash equilibrium solutions of two players tracking game for bilinear systems. A successive approximation approach is modified to design optimal controllers for bilinear systems. More specifically, a sequence of extended Sylvester differential equations are solved by this modified approach. A simulation example is given to demonstrate the validity of this approach. Copyright © 2012 John Wiley & Sons, Ltd.     

Optimal control of one‐dimensional cellular uptake in tissue engineering

A control problem motivated by tissue engineering is formulated and solved, in which control of the uptake of growth factors (signaling molecules) is necessary to spatially and temporally regulate cellular processes for the desired growth or regeneration of a tissue. Four approaches are compared for determining one‐dimensional optimal boundary control trajectories for a distributed parameter model with reaction, diffusion, and convection: (i) basis function expansion, (ii) method of moments, (iii) internal model control, and (iv) model predictive control (MPC). The proposed method of moments approach is computationally efficient while enforcing a nonnegativity constraint on the control input. Although more computationally expensive than methods (i)–(iii), the MPC formulation significantly reduced the computational cost compared with simultaneous optimization of the entire control trajectory. A comparison of the pros and cons of each of the four approaches suggests that an algorithm that combines multiple approaches is most promising for solving the optimal control problem for multiple spatial dimensions. Copyright © 2012 John Wiley & Sons, Ltd.     

C4d in Acute Rejection After Liver Transplantation—A Valuable Tool in Differential Diagnosis to Hepatitis C Recurrence

Hepatitis C is the most common indication for liver transplantation. Recurrence of HCV is universal leading to graft failure in up to 40% of all patients. The differentiation between acute rejection and recurrent hepatitis C is crucial as rejection treatments are likely to aggravate HCV recurrence. Histological examination of liver biopsy remains the gold standard for diagnosis of acute rejection but has failed in the past to distinguish between acute rejection and recurrent hepatitis C. We have recently reported that C4d as a marker of the activated complement cascade is detectable in hepatic specimen in acute rejection after liver transplantation. In this study, we investigate whether C4d may serve as a specific marker for differential diagnosis in hepatitis C reinfection cases. Immunohistochemical analysis of 97 patients was performed. A total of 67.7% of patients with acute cellular rejection displayed C4d-positive staining in liver biopsy whereas 11.8% of patients with hepatitis C reinfection tested positive for C4d. In the control group, 6.9% showed C4d positivity. For the first time we were able to clearly demonstrate that humoral components, represented by C4d deposition, play a role in acute cellular rejection after LTX. Consequently C4d may be helpful to distinguish between acute rejection and reinfection after LTX for HCV.     

弹性应变率比值法与声触诊组织量化技术联合诊断乳腺肿块的价值

目的：探讨弹性应变率比值法与声触诊组织量化技术(virtual touch tissue quantification,VTQ) 对乳腺肿瘤临床诊断准确性的价值。方法：选取大庆油田总医院乳腺外科接受手术治疗的60例女性乳腺肿瘤患者,患者知情同意后,对其依次进行常规超声检查、压迫式弹性成像(compression elastography,CE)检查、VTQ检查,CE检查取得应变率(strain ratio,SR)比值,VTQ测量剪切波的传播速度(shear wave velocity,SWV)值。并采受试者工作特征(receiver operating characteristic,ROC)曲线评价不同检查方法对乳腺肿瘤良恶性病变的诊断价值。结果：良性肿块的最大直径、SWV值均低于恶性肿块,良性肿块的SR比值高于恶性肿块,差异均具有统计学意义(P<0.01)。ROC曲线显示弹性应变率比值法与VTQ技术单用或联用的AUC、敏感性、特异性(分别为0.904,97.5%,69.2%;0.946,87.5%,87.2%;0.976,90%,97.4%)均高于常规超声(0.783,85%,61.5%);VTQ技术的AUC、特异性(0.946,87.2%)均高于弹性应变率比值法 (0.904,69.2%),但其敏感性(87.5%)低于后者(97.5%);弹性应变率比值法与VTQ技术联用的AUC和特异性均高于两者单用,但其敏感性较弹性应变率比值法低。结论：弹性应变率比值法与VTQ技术联用的诊断价值优于二者 单用。     

16例后肾腺瘤的临床病理特点及鉴别诊断

目的：探讨后肾腺瘤的临床病理特点及鉴别诊断要点。方法：回顾性分析2004年1月至2016年3月于北京大学第一医院治疗的16例后肾腺瘤患者的临床病理资料,结合文献讨论其发生的临床影像学特点、病理诊断、鉴别诊断、治疗和预后。结果：患者女性10例,男性6例,年龄14～83岁,平均年龄33.7岁。手术以肾部分切除为主,大体上肿瘤均位于肾实质的皮质区,3例突入肾窦,镜下观察肿瘤细胞排列成小腺泡状、乳头状及肾小球样结构,可见砂砾体形成。免疫组织化学染色显示,波形蛋白表达阳性率100%,CD57表达阳性率94%,WT1表达阳性率63%,广谱CK（AE/AE3）表达阳性率75%,CK7、AMACR表达率分别为19%、13%,CD10、NSE、CD56均阴性。16例患者随访1～125个月,均无复发或转移。结论：后肾腺瘤术前影像学诊断良性肿瘤特征不显著,诊断需依据独特的病理学特征,免疫组织化学染色CD57阳性是后肾腺瘤诊断和鉴别诊断的有用指标,以肾部分切除为主的外科治疗可达到治愈,临床预后好。     

经腹超声和经阴道超声对早期鉴别诊断子宫切口妊娠的价值比较

目的 探究经腹超声和经阴道超声对早期鉴别诊断子宫切口妊娠的实际诊断价值。方法 选取2016年2月～2019年2月我院产科收治的60例子宫切口妊娠孕妇作为研究对象,依据入院先后时间分为两组,每组30例。对照组采取经腹多普勒超声检测,观察组采取经阴道多普勒超声检测,与病理诊断结果相比较,分析经腹部与经阴道超声对子宫切口妊娠的分型诊断结果、符合率、特异性、灵敏度。结果 观察组诊断符合率达83.33%,灵敏度达84.62%,特异度达75.00%,高于对照组的诊断符合率60.00%、灵敏度68.42%、特异度45.45%(P0.05);观察组胚囊型符合率为68.75%(11/16),对照组为72.22%(13/18);早孕型符合率为60.00%(3/5),对照组为50.00%(2/4);不均质包块为88.89%(8/9),对照组为75.00%(6/8),两组三项符合率均无差异(P0.05)。结论 经阴道超声在对子宫切口妊娠的早期鉴别中相较经腹超声虽分型诊断结果无差异,但其具备符合率、特异性及灵敏度更高,因此诊断价值更高。     

2000—2022年人工智能应用于食管癌领域全球研究的可视化分析

背景 随着近20余年人工智能（AI）在食管癌领域应用研究的骤增,出现了许多关于该研究的系统、荟萃分析等,但其仅针对AI在该领域应用的单一方面的总结研究,研究人员难以全面了解领域最新发展与研究热点。目的 通过文献计量分析总结AI在食管癌领域的应用,阐明AI在食管癌领域相关研究的进展、热点和新兴趋势。方法检索Web of Science Core Collection(WoSCC)的Science Citation Index Expanded(SCI-E)数据库收录的AI应用于食管癌领域的所有英文文献,检索时间2000-01-01至2022-04-06。应用Microsoft Excel 2019、CiteSpace(5.8R3-64bit)和VOSviewer(1.6.18)对文献进行发文量、国家、作者、机构、共被引和关键词分析。结果 2000—2022年共检索到AI应用于食管癌领域的文献918篇,共计引用文献总量23 490篇。发文趋势：2000—2016年为迟缓期,发文量从6篇增至40篇;2017—2022年为快速增长期,发文量从62篇突增至216篇。60个国家、118家机构、5 ...     

从脾胃辨治口味异常

中医对口味异常的病因病机尚未形成统一认识,对该病的治疗亦是见仁见智。导师袁红霞教授认为,口味异常的形成是脏腑疾病反映于外的证候,善于从脾胃论治,重视调理气机升降,方药对证,效如桴鼓。本文撷取袁教授辨治口味异常验案6则供参考。