Non-spherical particles for optical trap assisted nanopatterning.

Optical trap assisted nanopatterning is a laser direct-write technique that uses an optically trapped microsphere as a near-field objective. The type of feature that one can create with this technique depends on several factors, one of which is the shape of the microbead. In this paper, we examine how the geometry of the bead affects the focus of the light through a combination of experiments and simulations. We realize nanopatterning using non-spherical dielectric particles to shape the light-material interaction. We model the resulting nanoscale features with a finite difference time domain simulation and obtain very good agreement with the experiments. This work opens the way to systematic engineering of the microparticle geometry in order to tailor the near-field focus to specific nanopatterning applications.

Parallel optical trap assisted nanopatterning on rough surfaces.

There exist many optical lithography techniques for generating nanostructures on hard, flat surfaces over large areas. However, few techniques are able to create such patterns on soft materials or surfaces with pre-existing structure. To address this need, we demonstrate the use of parallel optical trap assisted nanopatterning (OTAN) to provide an efficient and robust direct-write method of producing nanoscale features without the need for focal plane adjustment. Parallel patterning on model surfaces of polyimide with vertical steps greater than 1.5 µm shows a feature size uncertainty better than 4% across the step and lateral positional accuracy of 25 nm. A Brownian motion model is used to describe the positional accuracy enabling one to predict how variation in system parameters will affect the nanopatterning results. These combined results suggest that OTAN is a viable technique for massively parallel direct-write nanolithography on non-traditional surfaces.

Culture shock and a peace corps field mental health program.

The Peace Corps has developed a unique mental health guidance program to facilitate the selection and training of volunteers. It is pointed out, however, that there are some limitations in this overall program. The Peace Corps staff physician acts as the activator of preventive and curative psychiatric resources in the field. Culture shock provides the focal point for nearly all overseas adjustment problems. The author devised a field mental health program upon group therapy precepts in order to minimize the effects of adjustment dilemmas. A preliminary evaluation of this type of program with the Bolivian Peace Corps contingent indicates it is effective.

Teaching children self-care for chronic disease prevention: obesity reduction and smoking prevention.

A general health education program was developed for 1,252 students in six New York city area school districts. The purpose of the three-year project was to reduce the prevalence of risk factors associated with increased cardiovascular and cancer risk in adults. The curriculum included nutrition, antitobacco, and hypertension-control materials. A smaller, experimental intensive health behavior program was also developed for obese children (weight greater than or equal to 120% ideal for height, age, and sex). A smoking prevention program was offered to children with the aim of discouraging new smokers. Findings show that: 1) such a school-based primary disease prevention program is feasible and highly acceptable; and 2) reduction of obesity and new cigarette smoking occurred with intensive intervention involving small groups of students. On the other hand, a general health education itself had little effect in the total population in reducing the incidence of extreme clinical values (such as physical inactivity, high blood pressure, as well as smoking and obesity) for their age and sex. It is recommended that future programs for higher risk children concentrate on behavioral change rather than on general education.

Detection of antibody to cytomegalovirus-induced early antigens and comparison with four serologic assays and presence of viruria in blood donors.

Five hundred blood donors were evaluated for cytomegalovirus (CMV) viruria, antibody to CMV early antigens (EA-ab), CMV seropositivity by two screening assays, and CMV-specific immunoglobulin M by two methods. Three donors were viruric, EA-ab positive, and seropositive; two viruric donors were immunoglobulin M positive.

Genetic heterogeneity in human T-cell leukemia/lymphoma virus type II.

DNA from the peripheral blood mononuclear cells of 17 different individuals infected with human T-cell lymphoma/leukemia virus type II (HTLV-II) was successfully amplified by the polymerase chain reaction (PCR) with the primer pair SK110/SK111. This primer pair is conserved among the pol genes of all primate T-cell lymphoma viruses (PTLV) and flanks a 140-bp fragment of DNA which, when used in comparative analyses, reflects the relative degree of diversity among PTLV genomes. Cloning, sequencing, and phylogenetic comparisons of these amplified 140-bp pol fragments indicated that there are at least two distinct genetic substrains of HTLV-II in the Western Hemisphere. These data were confirmed for selected isolates by performing PCR, cloning, and sequencing with to 10 additional primer pair-probe sets specific for different regions throughout the PTLV genome. HTLV-II isolates from Seminole, Guaymi, and Tobas Indians belong in the new substrain of HTLV-II, while the prototype MoT isolate defines the original substrain. There was greater diversity among HTLV-II New World strains than among HTLV-I New World strains. In fact, the heterogeneity among HTLV-II strains from the Western Hemisphere was similar to that observed in HTLV-I and simian T-cell lymphoma/leukemia virus type I isolates from around the world, including Japan, Africa, and Papua New Guinea. Given these geographic and anthropological considerations and assuming similar mutation rates and selective forces among the PTLV, these data suggest either that HTLV-II has existed for a long time in the indigenous Amerindian population or that HTLV-II isolates introduced into the New World were more heterogeneous than the HTLV-I strains introduced into the New World.