Fabrication of Highly Ordered Nanoparticle Arrays Using Thin Porous Alumina Masks

Highly ordered nanoparticle arrays have been successfully fabricated by our group recently using ultra-thin porous alumina membranes as masks in the evaporation process. The sizes of the nanoparticles can be adjusted from 5-10 nm to 200 nm while the spacing between adjacent particles can also be adjusted from several nanometers to about twice the size of a nanoparticle. The configuration of the nanoparticles can be adjusted by changing the height of the alumina masks and the evaporation direction. Due to the high pore regularity and good controllability of the particle size and spacing, this method is useful for the ordered growth of nanocrystals. Different kinds of nanoparticle arrays have been prepared on silicon wafer including semiconductors (e.g., germanium) and metals (e.g., nickel). The germanium nanoparticle arrays have potential applications in memory devices while the nickel catalyst nanoparticle arrays can be used for the growth of ordered carbon nanotubes.Singapore-MIT Alliance (SMA

Inhibitory effects of bisbenzylisoquinolines on synthesis of the inflammatory cytokines interleukin-1 and tumour necrosis factor-alpha

Synthesis of IL-1β and TNFα by human monocytesmacrophages was significantly inhibited by eleven bisbenzylisoquinolines and one half-molecule (benzylisoquinoline), with IC50 values in the μM range. The results indicate that these compounds may have value in the therapy of human diseases where these inflammatory cytokines have a central role in pathogenesis

The ambivalent role of the physician in the child abuse syndrome

The reluctance of physicians to get involved with child abuse can be attributed to the problem of role conflict. Physicians derive their social authority from the Aesculapian tradition. This form of social authority is fragile and easily subverted, yet of utmost importance if physicians are to retain their effectiveness in the role of priest, healer and counsellor. In the child abuse syndrome, however, physicians are required by law and circumstances to report such cases to social welfare and law enforcement agencies. This at once casts the physician into the role of police collaborator. This ambivalence can be rationalised by regarding the family unit, rather than just the child, as the patient, and the referral to the social agencies as a "medical consultation"

How important is the myeloperoxidase microbicidal system of phagocytic cells?

The myeloperoxidase system is presented by most immunology textbooks as a major microbicidal system of phagocytic cells. This theory, however, has not been subjected to vigorous testing in the clinical arena. Of 14 patients with primary myeloperoxidase deficiency, only 3 had infectious complication. All 3 patients have more plausible explanations than myeloperoxidase deficiency for their infectious complications. Two of these patients were healthy until middle age when they developed systemic candidiasis after the onset of diabetes mellitus. The third patient was an infant with a maturational defect in neutrophil chemotaxis whose infectious complications ceased after the normalization of the chemotactic defect. The results of these "experiments of nature" indicate that the meyloperoxidase system is not a major microbicidal mechanism of phagocytic cells

Reptilian behavioural patterns in childhood autism

Childhood autism may be caused by damage to three phylogenetically distinct regions of the brain, or their major pathways and connections. Injury to the neocortex results in loss of language and cognitive function, while injury to the limbic cortex results in autistic withdrawal and abolition of play behaviour. Injury to the more primitive striatal complex, mammalian counterpart of the brain of reptiles, results in a bizarre and truncated form of stereotyped and ritualistic behaviour. The causes of brain injury in childhood autism could be those common in the perinatal period including cerebral anoxia, haemorrhage, phenylketonuria, neurolipidoses, meningitis, toxoplasmosis, and congenital rubella. All these conditions have previously been shown to be associated with childhood autism

Sociodemographic and motivational characteristics of parents who volunteer their children for clinical research: A controlled study

To determine the sociodemographic and motivational characteristics of parents who volunteer their children for clinical research. A questionnaire was administered to patients who volunteered their children for a randomised, double blind, placebo controlled trial of a drug to treat asthma and to a control group of parents whose children were eligible for the trial but had refused the invitation. 68 Parents who had volunteered their children and 42 who had not; a response rate of 94% and 70%, respectively. Responses of parents to questionnaire designed to assess their perceptions, attitudes, and health seeking behaviour as well as sociodemographic data. Volunteering parents were less well educated with only 15% (10/68) of mothers and 16% (11/68) and of fathers having had a tertiary or university education compared with 26% (11/42) of mothers and 45% (19/42) in the non-volunteering group. Fewer volunteering parents had professional or administrative jobs than did non-volunteering parents (mothers 6% (4/68); fathers 9% (6/68) v mothers 14% (6/42); fathers 31% (13/42)). Volunteering parents had less social support, and they displayed greater health seeking behaviour and consumed more habit forming substances. They were motivated by a desire to help others and to contribute to medical research, but they were also searching for more information and better ways to help their own children. Parents who volunteer their children for medical research are significantly more socially disadvantaged and emotionally vulnerable

Decay of granulocyte adherence following isolation from human blood

We studied the rate of decay of granulocyte adherence following isolation from human blood using the nylon-fibre microcolumn technique recently developed in our laboratory. The decay in adherence was found to be evident by 6 h, pronounced by 24 h, and very substantial by 48 h. This decay in adherence can be reversed by incubation at 4 °C instead of 37 °C. It can also be retarded by incubation with both superoxide dismutase and 2,3-dihydroxybenzoic acid. The data suggests that peroxidation of the granulocyte membrane is a possible mechanism for the decay in granulocyte adherence. These results provide further insight into biological aspects of granulocyte activity, and have implications for the laboratory evaluation of granulocyte function