Nanopore formation by low-energy focused electron beam machining.

The fabrication of nanopores in thin silicon nitride and aluminum oxide membranes by water vapor assisted, low-energy (0.2-20 kV) electron beam machining using a scanning electron microscope (SEM) is described. Using this technique, pores with diameters ranging in size from < 5 to 20 nm are easily formed. The nanopores are characterized by SEM, transmission electron microscopy (TEM) and atomic force microscopy (AFM). The mechanism of etching is briefly discussed.

Electron beam stimulated oxidation of carbon.

The patterning of carbon nanostructures by electron beam stimulated oxidation is described. Sputter deposited carbon thin films and carbon nanotubes are locally oxidized in a scanning electron microscope using injected water vapor. The resulting structures are examined with scanning electron microscopy and transmission electron microscopy. The electrical resistance obtained postprocessing is comparable to the as-deposited values. Linewidths are demonstrated down to 20 nm along with sub-2 nm nanowire fabrication in sputtered carbon films. A carbon nanowire is fabricated using this process and electrically characterized.

Microinstrument gradient-force optical trap.

A micromachined fiber-optic trap is presented. The trap consists of four single-mode, 1064-nm optical intersection. The beam fibers mounted in a micromachined silicon and glass housing. Micromachining provides the necessary precision to align the four optical fibers so that the outputs have a common intersection forms a strong three-dimensional gradient-force trap with trapping forces comparable with that of optical tweezers. Characterization of the multibeam fiber trap is illustrated for capture of polystyrene microspheres, computer simulations of the trap stiffness, and experimental determination of the trapping forces.

People who travel to be treated for HIV infection: keeping track for care management.

An HIV information exchange was established to provide district health authorities (DHAs) with current demographic and epidemiological data on residents infected with HIV. Reporters in each DHA in the Thames regions were asked to collect information about all HIV infected individuals treated within their districts during 1993. The information was collated at the PHLS AIDS Centre and summary tables were distributed to the DHAs involved describing their residents. We received reports of 7760 people infected with HIV and who were treated in the Thames regions in 1993. Thirty-five per cent were treated outside the region where they lived, 22% were treated within their region but outside their district of residence, and 43% were treated in the DHA where they lived. For 30 of the 38 DHAs the number of resident patients exceeded the number treated within the district. This exchange of information between DHA of treatment and DHA of residence showed that it is possible to provide summaries of current HIV case loads based on place of residence without compromising confidentiality. It also confirmed that many patients choose to be treated away from their area of residence.

Pornography and the paedophile: is it criminogenic?

There are few case-study-based reports of the role of pornography in the lives of sex offenders in contrast with numerous studies of a survey and statistical nature. Very little is known about the ways in which offenders process pornographic and other erotic materials as part of their offending patterns. The research reported in this study was based on case studies of fixated paedophiles in a private clinic for sex offenders. The men were interviewed about a range of matters including their offending, their psychosexual histories, pornography, fantasy, and sexual abuse in childhood. Commercial pornography was rarely a significant aspect of their use of erotica although some experience of such materials was typical of the men. Most common was 'soft-core' heterosexually oriented pornography. Explicit child pornography was uncommon. However, offenders also generated their own 'erotic' materials from relatively innocuous sources such as television advertisements, clothing catalogues featuring children modelling underwear, and similar sources. In no case did exposure to pornography precede offending-related behaviour in childhood. All of the offenders had experienced childhood sexual abuse by adults or older peers. The relationship of these findings to previous research and implications for legislation are noted.

The difficulties with low-level asbestos exposure assessments in public, commercial, and industrial buildings.

A method by which the airborne concentration of asbestos, low enough to substantiate that a significant health risk does not exist, is presented. The method is different from that used for the determination of occupational exposure, which is shown to be inadequate in this concentration range and a justification of how this alternative procedure might be used to achieve compliance is put forward. The difficulties associated with both the physical measurement and the significance of the concentrations that are determined are discussed.

A novel technique for the preparation of thin films for cross-sectional transmission electron microscopy.

A method is described for the preparation of cross-sectional samples of thin films for transmission electron microscopy. The technique produces larger amounts of thin region as compared with ion milling and eliminates the problems associated with ion beam damage. The requirement is that the films or multilayers must initially be deposited on a water-soluble substrate such as single-crystal NaCl.

Britain's "substance abuse policy": realities and regulation in the United Kingdom.

The historical development of policy concerning drugs in Great Britain is described. A major feature of this is that it originated out of international agreement rather than being the result of a domestic need. Not until the 1960s was there an emergence of evidence of a growing number of drug users. This led to the removal of the right to prescribe drugs in treatment from doctors in general practice and the establishment of clinics for the treatment of addicts. It is noted that the policy is substantially punitive and that large numbers of people are dealt with by the courts for drug offenses. The statistical data on drugs and the current treatment practices are also discussed.

Self-modelling and weight control.

This study investigated the use of self-modelling in the treatment of obesity or overweight. Thirty-two females enrolled in a private slimming club volunteered to participate in this study which was conducted over a period of 10 weeks. The experimental and control groups were similar as far as their pre-treatment mean weights and desired mean weights were concerned. Analysis of the data indicated that towards the end of the study the experimental group lost significantly more weight than the control groups. At the end of the study, the average weight loss for the experimental group was 4.27 pounds, for the control group I, 2.45 pounds, and for control group II, 3.66 pounds. Analysis of follow-up data collected six weeks after the end of the study confirmed this finding. At follow-up data collected six weeks after the end of the study confirmed this finding. At follow-up the mean weight loss was 8.27 pounds, 2.00 pounds for the experimental group, control group I and control group II, respectively. The data suggest that self-modelling can be used in the control of addictive behaviours.