Microscale Patterning of Mesoscopic PZN-PT Single Crystal Films by Crystal ion Slicing and Laser-Induced Etching

Advances in the fabrication of solid-solution single crystal relaxor ferroelectrics have made it possible to produce highly efficient piezoelectric crystals, and have attracted renewed interest in the use of these crystals for a new generation of piezoelectric transducers, actuators and sensors. Of particular interest is their incorporation into micro-electromechanical systems (MEMS). In this paper we report on the laser-induced wet chemical etching of lead zinc niobate-lead titanate (PZN-PT) in hydrochloric acid (HCl). Argon-ion laser radiation at power levels up to 4 W is focused to a spot diameter of about 15μm and results in the chemical etching of grooves at patterning speeds up to 5μm/sec. Crystal ion slicing, an ion-implant-based film separation technique, is used in combination with laser etching to form 5 to 10μm-thick patterned and freestanding films for incorporation into micro-electromechanical devices.     

Consumer knowledge of foodborne microbial hazards and food-handling practices.

A national telephone survey was conducted of 1,620 randomly selected U.S. residents who spoke English, were at least 18 years old, and resided in households with kitchen facilities. Respondents were interviewed about their recognition of foodborne pathogens, foods at risk for transmitting infection, knowledge of safe food handling, and food-handling practices. One-third of the respondents who prepared meals reported unsafe food hygiene practices: e.g., they did not wash hands or take precautions to prevent cross-contamination from raw meat. Unsafe practices were reported more often by men, adults 18 to 29 years of age, and occasional food preparers than by women, persons 30 years old or older, and frequent food preparers. Respondents who identified a food vehicle for Salmonella spp. were more likely to report washing their hands and cleaning cutting boards after preparing raw meat and poultry. The results raise concerns about consumer food-handling practices. The influence of food safety training, food-handling experience, and age on food-handling practices should be studied further. Awareness of a food vehicle for Salmonella spp., for example, may indicate knowledge of the etiology of foodborne disease that promotes safe food handling. Understanding the factors associated with safe food handling will assist in development of effective safe-food instruction programs.     

An analysis of the Slapper worm

We can prove that the Slapper is a variation of the Apache Scalper worm by comparing the source code. Modifications introduced in the Slapper worm improved the robustness and efficiency of its predecessor's simplistic P2P networking capabilities. Slapper's author also removed certain features from the original-either because they were redundant or to reduce the perception that it was a tool developed to cause direct harm to networks. Among the features the author removed from the Slapper were capabilities to update itself from a remotely specified Web server (perhaps to prevent someone else from replacing this version with a new one), to attack and infect a host specified with a controlling program, and to send spans. Interestingly, the ability to execute distributed denial-of-service attacks on a controlling user's behalf was kept intact. Slapper's author attempted to make communications with a remote controlling program as stealthy and untraceable as possible by removing several commands to query status and obtain feedback from Slapper nodes.     

A Study of The Moisture-Uptake Kinetics of a Hygroscopic Pharmaceutical Powder

The moisture-uptake kinetics of a hygroscopic powder, sodium heparin contained in a cylindrical container, was determined using a novel moisture-uptake measuring device under a constant convective air flow. The amount of moisture uptake increased with the increase in the relative humidity of the air. The effect of powder-bed height on the total amount of moisture uptake was found to be significant only at the highest relative humidity (75%) evaluated in this study. However, the percent of weight increase of the powder as a result of moisture uptake decreases as the height of the powder bed increases. The results of this study are explained by the dynamic nature of the moisture-uptake process associated with the instrument.     

Peripheral intravenous infusion--another cause of air embolism

We report an unusual complication of intravenous infusion. A 4-week-old baby developed acute cardiopulmonary distress because of air embolism caused by improper preparation of peripheral intravenous set. The estimated amount of infused air was 12 ml (approximately 3.5 ml/kg). The infant recovered promptly after short supportive treatment.     

The first measurement of an absolute surface concentration of reaction intermediates in ethylene hydrogenation

The first measurement of a turnover rate with respect to surface intermediate concentration in a high pressure heterogeneous catalytic reaction is reported. By using infrared-visible sum frequency generation to study the hydrogenation of ethylene on Pt(111), it was found that the surface concentration of -bonded ethylene, the key reaction intermediate, represented approximately 4% of a monolayer. Thus the absolute turnover rate per surface adsorbed ethylene molecule is 25 times faster than the rate measured per platinum atom. To explain these results, we propose a model of weakly adsorbed ethylene intermediates reacting on atop sites.     

Grain nucleation and texture analysis of electroless copper deposition on a palladium seed layer

Electroless copper grains were deposited on a Pd seed layer under varying bath conditions. The seed layer was determined to have a (111) texture using grazing incident x-ray (GIX) diffraction. Multiple nucleation sites in the grain boundaries were imaged using a scanning tunneling microscope. Continual copper growth produced row-like structures. The texture of the electrolessly deposited copper (ED-Cu) grains were determined to be (111). No radial grain orientation for the Pd seed layer or the ED-Cu thin film was detected using GIX diffraction. Atomic force microscope images indicated continual Cu nucleation throughout the deposition process. PdH was formed as a by-product of the electroless deposition process, and detected by x-ray diffraction.     

Parental Mediation of Children's Television Viewing in Low-Income Families

Studies of parental mediation of children's television viewing have included samples of mostly middle- and upper-class Caucasian parents. These studies have only begun to examine mediation in the context of parent-child relationships. This study of 306 low-income, predominately African American mothers assesses macro- and microlevel influences on viewing mediation using Bronfenbrenner's ecological theory of child development. It was hypothesized that factors outside the home (e.g., work hours) influence parents' involvement with children, which, in turn, was predicted to influence viewing mediation. Results supported this model for coviewing and instructive mediation, but not for viewing restrictions.