Fiber-reinforced composite materials are replacing metallic components due to their higher specific strength and stiffness. Automation and thermoplastics emerged to overcome the time and labor intensive manual techniques and the long curing cycles associated with processing thermoset-based composites. Thermoplastics are processed through fusion bonding which involves applying heat and pressure at the interface. Together with automated techniques (such as automated fiber placement, and automated tape laying), a fast, clean, out-of-autoclave, and automated process can be obtained. A detailed review of thermoplastic composites processing through automated methods is presented. It sheds the light on the materials used and the different heat sources incorporated with the pros and cons of each, with concentration mainly on hot gas torch, laser, and ultrasonic heating. A thorough illustration of the several mechanisms involved in a tow/tape placement process is tackled such as heat transfer, intimate contact development, molecular interdiffusion, void consolidation and growth, thermal degradation, crystallization, and so on. Few gaps and recommendations are included related to materials, laser heat source, heat transfer model, and the use of silicone rubber rollers. A review of optimization studies for tape placement processes is summarized including the main controllable variables and product quality parameters (or responses), with some of the major findings for laser and hot gas torch systems being presented. Both mechanical and physical characterizations are also reviewed including several testing techniques such as short beam shear, double cantilever beam, lap shear, wedge peel, differential scanning calorimetry, and so on. Challenges, however, still exist, such as achieving the autoclave-level mechanical properties and complying with the porosity levels required by the aerospace industry. More work is still necessary to overcome these challenges as well as increase the throughput of the process before it can be totally commercialized.

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Diarrhea is a leading cause of mortality and morbidity in developing countries. In Egypt, researchers have traditionally been targeting diarrhea-related mortality. This study is an attempt to portray the morbidity and risk factors of diarrhea among children under 5 years old (under-fives) in rural Upper Egypt. The incidence of diarrhea in the 6 months before the study was determined among 1025 under-fives in six sentinel sites by interviewing mothers or caretakers. The association between diarrhea and a set of risk variables was examined using a multivariate logistic regression model. Variables that appeared to have a significant predictive power were then included in a forward wald stepwise logit analysis model to estimate statistical functions which best predict the diarrheal morbidity. The incidence rate of diarrhea was found to be 3.6 episodes per child semiannually and the point prevalence was 19.5 per cent. The average duration of current episodes was 4.8 +/- 3.7 days; 33.6 per cent of children had had diarrhea more than three times (recurrent diarrhea). Four variables were found to have a significant association with recurrent diarrhea. The logit coefficients and their significance levels indicated that, in order of contribution to risk prediction, the variables ranked as follows: household meat consumption, mother's age at the time of birth of the child, child's age, and father's illiteracy. A total of 74.8 per cent of overall children were correctly predicted by these risk factors, a figure which indicates the goodness of fit of the model. It is concluded that the diarrheal morbidity is still unacceptably high in rural Upper Egypt. More interventions are needed to control for specific risk factors.

In Palestine, there has been an increase in the reported incidence of acute hepatitis A virus (HAV) infection since 1995. Since overt clinical disease occurs only among adults, questions were raised whether or not a shift in the epidemiology of HAV has occurred. This is generally characterized by a decrease in the overall incidence rate and a shifting in the mean age of infection towards adolescence and early adulthood. The need for a vaccination programme is being discussed. To resolve this issue, we examined the prevalence of anti-HAV in a representative sample of 396 school children in the Gaza Strip. The prevalence of anti-HAV was 93.7% (95% CI: 91.3, 96.1%). Stratifying the prevalence by age showed that 87.8% (95% CI: 78.6, 97%) were HAV antibody positive by the age of 6. By the age of 14, almost 98% (95% CI: 92.7, 100%) were HAV antibody positive. This means that the majority of HAV infection is still taking place in early childhood, when it is usually asymptomatic and of little clinical significance. The results refuted the shifting epidemiology theory and we recommend that a vaccination programme against HAV infection is not yet needed. Alternative explanations for the increase in reported cases are discussed.

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