基于普通向量的虹膜识别算法

典型的虹膜识别算法都是针对单个虹膜样本采用图像处理的方法提取虹膜特征,只强调个体信息,而忽略了虹膜样本间的联系.本文提出了一种基于普通向量的虹膜识别算法,从模式分析的角度,利用普通向量方法融合虹膜的个体特征和统计特征,并且通过高效的睫毛滤除和眼皮定位的算法,进一步提高了识别的精度和算法的稳定性.实验结果表明了该算法具有良好的性能.     

Multifunctional Transmembrane Protein Ligands for Cell‐Specific Targeting of Plasma Membrane‐Derived Vesicles

Liposomes and nanoparticles that bind selectively to cell‐surface receptors can target specific populations of cells. However, chemical conjugation of ligands to these particles is difficult to control, frequently limiting ligand uniformity and complexity. In contrast, the surfaces of living cells are decorated with highly uniform populations of sophisticated transmembrane proteins. Toward harnessing cellular capabilities, here it is demonstrated that plasma membrane vesicles (PMVs) derived from donor cells can display engineered transmembrane protein ligands that precisely target cells on the basis of receptor expression. These multifunctional targeting proteins incorporate (i) a protein ligand, (ii) an intrinsically disordered protein spacer to make the ligand sterically accessible, and (iii) a fluorescent protein domain that enables quantification of the ligand density on the PMV surface. PMVs that display targeting proteins with affinity for the epidermal growth factor receptor (EGFR) bind at increasing concentrations to breast cancer cells that express increasing levels of EGFR. Further, as an example of the generality of this approach, PMVs expressing a single‐domain antibody against green fluorescence protein (eGFP) bind to cells expressing eGFP‐tagged receptors with a selectivity of ≈50:1. The results demonstrate the versatility of PMVs as cell targeting systems, suggesting diverse applications from drug delivery to tissue engineering.     

Synthesis, biochemical evaluation, and classical and three-dimensional quantitative structure-activity relationship studies of 7-substituted-1,2,3,4-tetrahydroisoquinolines and their relative affinities toward phenylethanolamine N-methyltransferase and the alpha2-adrenoceptor

7-Substituted-1,2,3,4-tetrahydroisoquinolines (7-substituted-THIQs) are potent inhibitors of phenylethanolamine N-methyltransferase (PNMT, EC 2.1.1.28), the enzyme involved in the biosynthesis of epinephrine. Unfortunately, most of these compounds also exhibit strong affinity for the alpha2-adrenoceptor. To design a selective (PNMT vs alpha2-adrenoceptor affinity) inhibitor of PNMT, the steric and electrostatic factors responsible for PNMT inhibitory activity and alpha2-adrenoceptor affinity were investigated by evaluating a number of 7-substituted-THIQs. A classical quantitative structure-activity relationship (QSAR) study resulted in a three-parameter equation for PNMT (PNMT pKi = 0.599pi - 0.0725MR + 1. 55sigmam + 5.80; n = 27, r = 0.885, s = 0.573) and a three-parameter equation for the alpha2-adrenoceptor (alpha2 pKi = 0.599pi - 0. 0542MR - 0.951sigmam + 6.45; n = 27, r = 0.917, s = 0.397). These equations indicated that steric effects and lipophilicity play a similar role at either active site but that electronic effects play opposite roles at either active site. Two binding orientations for the THIQs were postulated such that lipophilic and hydrophilic 7-substituents would not occupy the same region of space at either binding site. Using these two binding orientations, based on the lipophilicity of the 7-substituent, comparative molecular field analysis (CoMFA) models were developed that showed that the steric and electrostatic interactions at both sites were similar to those previously elaborated in the QSAR analyses. Both the QSAR and the CoMFA analyses showed that the steric interactions are similar at the PNMT active site and at the alpha2-adrenoceptor and that the electrostatic interactions were different at the two sites. This difference in electrostatic interactions might be responsible for the selectivity of THIQs bearing a nonlipophilic electron-withdrawing group at the 7-position. These QSAR and CoMFA results will be useful in the design of potent and selective (PNMT vs alpha2-adrenoceptor affinity) inhibitors of PNMT.     

Intracerebral hemorrhage after carotid endarterectomy: incidence, contribution to neurologic morbidity, and predictive factors

PURPOSE: With a diminishing rate of cardiac and neurologic events after carotid endarterectomy, intracerebral hemorrhage is gaining increasing importance as a cause of perioperative morbidity and mortality. To date, information has been largely anecdotal, and there has been no comparison with a control group of patients. METHODS: The records of all patients experiencing symptomatic intracerebral hemorrhage after carotid endarterectomy were reviewed and compared with data from 50 randomly selected patients who did not experience intracranial bleeding. Univariate analyses were performed, using the Fisher exact test for dichotomous data and the Student t test for continuous data. RESULTS: During a 6-year period, symptomatic intracranial hemorrhage developed in 11 (0.75%) of 1471 patients undergoing carotid endarterectomy, accounting for 35% of the 31 total perioperative neurologic events. Hemorrhage occurred a median of 3 days postoperatively (range, 0 to 18 days). Signs and symptoms included hypertension in all 11 patients, headache in 7 conscious patients (64%), and bradycardia in 6 patients (55%). Massive hemorrhage with herniation and death occurred in 4 patients (36%). Moderate hemorrhage developed in 5 patients (45%); 3 of these patients had partial recovery, and 2 had complete recovery. Petechial hemorrhage occurred in the remaining 2 patients (18%), 1 with partial and 1 with complete recovery. In comparison with the control group, there were no differences in respect to sex, indication for operation, smoking or diabetic history, and antiplatelet therapy or perioperative heparin management. Patients with intracranial hemorrhage were, however, younger, more frequently hypertensive, had a higher degree of ipsilateral and contralateral carotid stenosis, and had a higher rate of contralateral carotid occlusion. CONCLUSION: Intracranial hemorrhage occurs with notable frequency after carotid endarterectomy and accounts for a significant proportion of neurologic morbidity and mortality. Younger patients, hypertensive patients, and patients with severe cerebrovascular occlusive disease appear to be at greatest risk for the complication.     

Modular framework support for context-aware mobile cinema

In this paper we describe a novel approach for interactive cinema based on context-aware narration using handheld computers. The paper describes both the artistic approach and the ubiquitous computing framework developed to realize the scenario. This framework has been used in various projects, including the described video production course at the ISNM, where five interactive cinema concepts have been developed and shown during a public demonstration. In our approach, a new type of user experience has been established by placing the viewer inside the movie’s physical locations during playback. Moreover, the developed ubiquitous computing framework provides a foundation for future work in the area of ad-hoc, service-oriented Ubicomp scenarios.     

Strain estimation for external event loads

It is common knowledge that structural design on the basis of stress limitation leads to an overestimation of the damage potential of low cycle dynamic loads (e.g. seismic events).Until now the high effort needed for step-by-step numerical evaluation of nonlinear dynamic structural response is a serious obstacle for a more realistic design based on strain limitation.The concept of energy dissipation and structural hardening as functions of strain range leads to the definition of a set of 1-DOF-substitute structures gained by a limited number of quasi-static non linear computations or by a certain knowledge of the yield behaviour of structural members. Step-by-step numerical computations are restricted to the substitutes and thus the effort for a strain limitation design is reduced to a bearable level.