Subcutaneous zygomycosis due to Saksenaea vasiformis: rapid isolate identification using a modified sporulation technique

Saksenaea vasiformis, a zygomycete belonging to the order Mucorales, is a rare cause of zygomycosis with 17 cases documented world-wide. It usually infects the immunocompromised or traumatized and has a high mortality rate. Because of its failure to sporulate under normal laboratory conditions it may be difficult to identify. We describe here an unusual case report of Saksenaea vasiformis with sporulation and identification within a week using a modified sporulation technique.     

Improvement of Heater Surface Flatness and Uniformity of TiN Film Deposition

The deposition rate and the thickness uniformity of chemical vapor deposition (CVD) titanium nitride films depend on wafer temperatures. The heater surface conditions, such as flatness, roughness, and surface imperfections, can greatly affect heat transfer efficiency from the heater surface to the wafer, and the process performance. Because heater surface imperfections or “hot spots” that caused poor uniformity had to be eliminated, the origin of “hot spots” was identified by a detailed study of heater surface profiles. A better visualization of “hot spots” could be obtained by comparing wafer-chucking patterns with deposition patterns. Thus, the time needed to locate “hot spots” could be shortened. The manufacturing process was revised to prevent “hot spots” and improve heater performance.     

Game strategies in network security

This paper presents a game-theoretic method for analyzing the security of computer networks. We view the interactions between an attacker and the administrator as a two-player stochastic game and construct a model for the game. Using a nonlinear program, we compute Nash equilibria or best-response strategies for the players (attacker and administrator). We then explain why the strategies are realistic and how administrators can use these results to enhance the security of their network.     

Face recognition with radial basis function (RBF) neural networks

A general and efficient design approach using a radial basis function (RBF) neural classifier to cope with small training sets of high dimension, which is a problem frequently encountered in face recognition, is presented. In order to avoid overfitting and reduce the computational burden, face features are first extracted by the principal component analysis (PCA) method. Then, the resulting features are further processed by the Fisher's linear discriminant (FLD) technique to acquire lower-dimensional discriminant patterns. A novel paradigm is proposed whereby data information is encapsulated in determining the structure and initial parameters of the RBF neural classifier before learning takes place. A hybrid learning algorithm is used to train the RBF neural networks so that the dimension of the search space is drastically reduced in the gradient paradigm. Simulation results conducted on the ORL database show that the system achieves excellent performance both in terms of error rates of classification and learning efficiency.     

Surgical Revision and Early Cannulation of the Arteriovenous Fistula in Hemodialysis Patients: An Effective Technique

Arteriovenous fistula (AVF) dysfunction is a common problem in hemodialysis patients. After surgical revision for malfunction, we used AVFs early to avoid complications associated with central venous catheters. In this study, we report experience with surgical revisions of native AVFs with suspected arterial dysfunction as the cause of inadequate arterial inflow for dialysis. Exclusion criteria were presence of a central venous catheter as a hemodialysis access, and clinical or radiologic evidence of stenosis or thrombosis of the distal venous segment of the AVF. We prospectively studied 50 patients (mean age 60.2 ± 10.5 years, 25 men and 25 women) with 59 revisions. The patients were followed until change in the modality of dialysis, transplant, or death. The types of AVFs revised were left wrist radiocephalic in 27 patients (54%), left forearm radiocephalic in 10 (20%), right wrist radiocephalic in 6 (12%), left antecubital brachiocephalic in 3 (6%), right antecubital brachiocephalic in 2 (4%), and right forearm radiocephalic in 2 (4%). The causes of inadequate arterial flow were juxta‐anastomotic thrombosis in 20 patients (40%), inadequate arterial anastomotic flow in 16 (32%), inadequate anastomosis in 7 (14%), and juxta‐anastomotic venous stenosis in 7 (14%). The primary surgical revision techniques were proximal neo‐anastomosis using the semiarterialized vein in 43 patients (86%), thrombectomy and re‐anastomosis in 5 (10%), and resection and repair in 2 (4%). Technical success, defined as successful cannulation of the revised AVF for hemodialysis and avoidance of central venous catheter, was achieved in 44 of 50 patients (88%). Technical failure occurred 6 cases, the causes being inadequate arterial flow in 3 patients, failure to cannulate the veins in 2 patients, and steal syndrome in 1 patient. After primary revisions failed, 9 re‐revisions were done in 6 patients. The 1‐year, 2‐year, and 3‐year primary and overall patency rates were 76.2%, 67.6%, 65.0%, and 85.7%, 75.7%, 65.0%, respectively. In conclusion, surgical salvage of the AVF with inadequate arterial flow is an effective approach that can be performed as an outpatient procedure and allows early cannulation of the semi‐arterialized veins, thus avoiding the use of central venous catheters.     

Error rates for narrow-band digital FM with discriminator detectionin mobile radio systems

Error rates for a narrowband digital FM system with discriminator detection in a land mobile radio channel characterized by fading and Doppler frequency shift are obtained using a new analytical method. The fading rate is assumed to be much slower than the bit rate so that signal distortion through a narrow bandpass filter can be analyzed via a quasistatic approach. An experiment was conducted using a Rayleigh fading simulator, and the error rate measurements are shown to agree well with the calculated results, except at high SNR (signal-to-noise ratio) where an irreducible error rate was observed     

Design guidelines for processing bi-material components via powder-injection molding

Powder injection molding can be used to fabricate bi-material components that provide unique functionality such as a combination of toughness and wear resistance. Successful processing of these components requires minimization of internal stresses during sintering. In this article, the stresses generated during co-sintering of concentric rings are analyzed, compared to the materials’ strengths, and correlated with defects. The results provide guidelines for determining the compatibility of various materials and the effect of component geometry. For more information, contact John L. Johnson, AMTellect, 302 South Burrowes Street, State College, PA 16801; (814) 861-8090; fax (814) 861-8003; e-mail john@amtellect.com.     

ECoDE – An Environmental Component Design Evaluation Tool

. Mass consumerism has brought about increasing consumption of non-renewable natural resources and manufactured goods, and is creating a waste disposal problem of unprecedented magnitude in the process. In the long run, sustainable manufacturing is only attainable given environmentally responsible product design. There are many tools for the analysis of the impact of manufactured products on the environment, but they do not offer a level of detail sufficient to identify environmentally offensive components in the product. This paper discusses a computer-based design evaluation tool, ECoDE, developed for assessing the environmental impact of components in a product. ECoDE makes use of the Analytical Hierarchy Process to compare each criterion, and rank them in an ascending order of relative significance. The types of materials used, their costs, manufacturing processes, reliability, and ease of access for disassembly are some of the key assessment criteria being considered. Finally, a multi-attribute (or criteria) rating technique is used to compute the scores against each of the criteria for both components and the overall product. The larger the score, the less severe the impact of the component or product on the environment. A discussion is then made on an evaluation test case conducted by ECoDE. Preliminary tests have found that ECoDE is able to calculate the least environmentally friendly component and highlight its likely causes.     

A comparison of two techniques for ankle jerk assessment in elderly subjects

The reported prevalence of absent ankle jerks in elderly people varies greatly. This variation may be due to differences in the method of testing. Eight physicians examined 12 patients for the presence of ankle jerks using two techniques: plantar strike and tendon strike. Both intra-observer agreement (kappa 0.47 vs 0.20; p = 0.01) and inter-observer agreement (0.57 vs 0.21; p < 0.001) were greater with plantar strike. Reliability of ankle jerk assessment was greater for more experienced examiners. Differences in technique may explain some of the discrepancy between studies examining the prevalence of absent ankle jerks in elderly people.     

Study of rubber oxidation by thermoanalysis

A method using the DSC was utilized whereby the oxidation of natural rubber was studied by adapting the procedures developed by Kissinger, Doyle, and Ozawa for thermoanalysis. Thus oxidative induction time of several hours for a particular rubber sample can be estimated in a relatively short time. Some of the results of this method are compared with those from other established methods, the estimated oxidative induction time showing a good correlation with some of the systems tested. The validity and limitations of this method are discussed.