A novel fuzzy clustering algorithm for the analysis of axillary lymph node tissue sections

Recently Fourier Transform Infrared (FTIR) spectroscopic imaging has been used as a tool to detect the changes in cellular composition that may reflect the onset of a disease. This approach has been investigated as a mean of monitoring the change of the biochemical composition of cells and providing a diagnostic tool for various human cancers and other diseases. The discrimination between different types of tissue based upon spectroscopic data is often achieved using various multivariate clustering techniques. However, the number of clusters is a common unknown feature for the clustering methods, such as hierarchical cluster analysis, k-means and fuzzy c-means. In this study, we apply a FCM based clustering algorithm to obtain the best number of clusters as given by the minimum validity index value. This often results in an excessive number of clusters being created due to the complexity of this biochemical system. A novel method to automatically merge clusters was developed to try to address this problem. Three lymph node tissue sections were examined to evaluate our new method. These results showed that this approach can merge the clusters which have similar biochemistry. Consequently, the overall algorithm automatically identifies clusters that accurately match the main tissue types that are independently determined by the clinician.     

Functions for relative maximization

We introduce functions for relative maximization in a general context: the beta and alpha applications. After a systematic study of different kinds of regularities, we investigate how to approximate certain values of these functions using periodic orbits. We also show that the differential of an alpha application determines the asymptotic behavior of the optimal trajectories.     

Anomaly Detection in a Reactor Coolant Pump Flywheel System via Pulse Shape Analysis

In this study, a method that discriminates between anomalies present or absent in the vibration signal of a flywheel system is developed. First by means of MATLAB and Simulink, a simple flywheel system under different feasible conditions is simulated using equations of motion to capture the dynamic behaviors of the components of the system along their lines of action. The resulting vibration signals obtained from the simulations are combined with varying levels of noise and then subjected to pulse shape analysis (PSA). PSA is a tool that has been mostly used in the field of nuclear engineering, and it is explored and used differently here with the objective of developing a suitable PSA algorithm that can differentiate between vibration signals based on the presence or absence of an anomaly. The algorithm is a time-domain technique with minimal computational time that can be very easily applied. At the end, it is shown that the developed PSA algorithm can identify an anomaly in a vibration signal on the basis of a defined pattern under certain attainable conditions.     

Impact of air‐handling system exhaust failure on dissemination pattern of simulant pathogen particles in a clinical biocontainment unit

Biocontainment units (BCUs) are facilities used to care for patients with highly infectious diseases. However, there is limited guidance on BCU protocols and design. This study presents the first investigation of how HVAC (heating, ventilation, air‐conditioning) operating conditions influence the dissemination of fluorescent tracer particles released in a BCU. Test conditions included normal HVAC operation and exhaust failure resulting in loss of negative pressure. A suspension of optical brightener powder and water was nebulized to produce fluorescent particles simulating droplet nuclei (0.5‐5 μm). Airborne particle number concentrations were monitored by Instantaneous Biological Analyzers and Collectors (FLIR Systems). During normal HVAC operation, fluorescent tracer particles were contained in the isolation room (average concentration = 1 × 10⁴ ± 3 × 10³/L_air). Under exhaust failure, the automated HVAC system maximizes airflow into areas adjacent to isolation rooms to attempt to maintain negative pressure differential. However, 6% of the fluorescent particles were transported through cracks around doors/door handles out of the isolation room via airflow alone and not by movement of personnel or doors. Overall, this study provides a systematic method for evaluating capabilities to contain aerosolized particles during various HVAC scenarios. Recommendations are provided to improve situation‐specific BCU safety.     

Antimicrobial prophylaxis for catheter-associated bacteriuria

We evaluated short-term systemic antimicrobial prophylaxis for catheter-associated bacteriuria in women undergoing elective gynecological operations in a prospective, controlled, double-masked study. Nine of 100 placebo-treated patients acquired bacteriuria during catheterization compared with 3 of 96 of the drug-treated group. However, at the time of hospital discharge, clean-voided urine specimens were positive as frequently in the drug-treated group (8 of 82 patients cultured) as in the placebo group (8 of 75 patients cultured). No difference in febrile morbidity due to bacteriuria was noted between the prophylaxis and placebo groups. The incidence of catheter-associated bacteriuria may be reduced by antimicrobial prophylaxis. However, because the protective effect is transient and is associated with the selection of resistant organisms, prophylaxis is not indicated for patients at low risk for acquired bacteriuria and in whom the sequelae of catheter-associated infections are infrequent.     

GP challenge: evolving energy function for protein structure prediction

One of the key elements in protein structure prediction is the ability to distinguish between good and bad candidate structures. This distinction is made by estimation of the structure energy. The energy function used in the best state-of-the-art automatic predictors competing in the most recent CASP (Critical Assessment of Techniques for Protein Structure Prediction) experiment is defined as a weighted sum of a set of energy terms designed by experts. We hypothesised that combining these terms more freely will improve the prediction quality. To test this hypothesis, we designed a genetic programming algorithm to evolve the protein energy function. We compared the predictive power of the best evolved function and a linear combination of energy terms featuring weights optimised by the Nelder–Mead algorithm. The GP based optimisation outperformed the optimised linear function. We have made the data used in our experiments publicly available in order to encourage others to further investigate this challenging problem by using GP and other methods, and to attempt to improve on the results presented here.     

Relation between different inclusion-matrix interfaces in steels and the susceptibility to hydrogen embrittlement

The susceptibility to hydrogen damage of different steels with several heat treatments was studied in specimens hydrogenated during tensile testing. The initiation of localized cracking in hydrogenated specimens was dependent on the possibility of development of a critical hydrogen concentration, in the cavities and/or microcracks associated with undeformable inclusions such as Al₂O₃. The induction time to reach the critical hydrogen concentration depends on the hydrogen charging conditions, the matrix strength level and the undeformable inclusion content. The effect of the sulphur content in the steel and the MnS inclusion content is not important to the susceptibility of the steel to hydrogen damage.     

Cephalosporin vs penicillin

Smaller individual series on the outcome of laparoscopic hernioplasty techniques have been reported. This study reports on the complications of 3,229 laparoscopic hernia repairs performed by the authors in 2,559 patients. The TAPP (transabdominal preperitoneal) technique was the most frequently performed: 1,944 (60%). The totally preperitoneal technique was performed 578 (18%) times. The IPOM (intraperitoneal onlay mesh) repair was performed 345 (11%) times. The plug-and-patch technique was used 286 (9%) times and simple closure of the hernia defect without mesh was used in 76 (2%) repairs. Overall, there were 336 (10%) complications: 17 (0.5%) major and 265 (8%) minor. There were 54 (1.6%) recurrences, with a mean follow-up of 22 months. The TAPP technique had 19 (1%) recurrences and 141 (7%) complications. There were four bowel obstructions in this subgroup from herniation of small bowel through the peritoneal closure and trocar sites. The totally preperitoneal technique had no recurrence and 60 (10%) complications. The IPOM group had 7 (2%) recurrences and 47 (14%) complications. The plug-and-patch technique had 26 (9%) recurrences and 24 (8%) complications. The simple closure of the internal ring had 2 (3%) recurrences and 10 (13%) complications. Laparoscopic hernioplasty is not without complications. Laparoscopic hernioplasty is not without complications. Training, experience, and attention to technique will prevent some of these complications.