In Situ Observation of Zirconia Particles at 1200°C by High-Resolution Electron Microscopy

Zirconia (ZrO₂) particles (average diameter, 30 nm) were observed in an in situ heating experiment up to 1200°C using a 400-kV high-resolution electron microscope. Thermal vibration of atoms on a (001) surface plane was observed at 1100°C. At 1200°C, grain growth and sintering phenomena were recorded on a videotape, showing (100) lattice planes migrating on a surface of a particle. Direct observation of the sintering process on a lattice level was accomplished for the first time.     

Size effect in the low-field Hall coefficient of single-crystal copper films

Measurements of the low-field Hall coefficientR _H of single-crystal copper films were made at 4.2 K by the use of a SQUID. The surface normaln of the samples was directed in the [100], [110], and [111] directions and the ratio of the thickness to the mean free path ranged from 0.1 to 0.7. It is found that the effect of surface scattering causesR _H to decrease whenn [100], whereas it causesR _H to increase whenn [110] and [111]. This behavior is interpreted in terms of the geometrical characteristics of the Fermi surface.     

Does Bisphenol A Confer Risk of Neurodevelopmental Disorders? What We Have Learned from Developmental Neurotoxicity Studies in Animal Models

Substantial evidence indicates that bisphenol A (BPA), a ubiquitous environmental chemical used in the synthesis of polycarbonate plastics and epoxy resins, can impair brain development. Clinical and epidemiological studies exploring potential connections between BPA and neurodevelopmental disorders in humans have repeatedly identified correlations between early BPA exposure and developmental disorders, such as attention deficit/hyperactivity disorder and autism spectrum disorder. Investigations using invertebrate and vertebrate animal models have revealed that developmental exposure to BPA can impair multiple aspects of neuronal development, including neural stem cell proliferation and differentiation, synapse formation, and synaptic plasticity—neuronal phenotypes that are thought to underpin the fundamental changes in behavior-associated neurodevelopmental disorders. Consistent with neuronal phenotypes caused by BPA, behavioral analyses of BPA-treated animals have shown significant impacts on behavioral endophenotypes related to neurodevelopmental disorders, including altered locomotor activity, learning and memory deficits, and anxiety-like behavior. To contextualize the correlations between BPA and neurodevelopmental disorders in humans, this review summarizes the current literature on the developmental neurotoxicity of BPA in laboratory animals with an emphasis on neuronal phenotypes, molecular mechanisms, and behavioral outcomes. The collective works described here predominantly support the notion that gestational exposure to BPA should be regarded as a risk factor for neurodevelopmental disorders.     

Phage‐mediated transfer of virulence genes

Bacteriophages as accessory genetic elements play a crucial role in the dissemination of genes and the promotion of genetic diversity within bacterial populations. Such horizontal transfer of DNA is critical in the emergence of new pathogenic organisms, through the dissemination of genes encoding virulence factors such as toxins, adhesins and agressins. Phages can transfer genes that are not necessary for bacteriophage persistence and are generally recognised by their ability to convert their host bacteria to new phenotypes. This phenomenon is known as phage conversion. If such converting genes encode for virulence factors, the consequences of phage infection may include increased virulence of the host bacteria, and the conversion of a non‐pathogenic strain to a potentially dangerous pathogen. A number of virulence factors in bacteria causing diseases in plants, animals and humans are encoded by converting phages, the vast majority of which are temperate as opposed to lytic in nature. © 2001 Society of Chemical Industry     

Quantum Oscillations of Thermoelectric Effects in a Pseudo-one-dimensional Electron Gas With a Spin–Orbit Interaction

We consider thermoelectric effects in a pseudo-one-dimensional electron gas (P1DEG) with a spin–orbit interaction (SOI). The SOI splits the dispersion relation of the P1DEG into subbands with an energy gap. We find quantum oscillations in transport coefficients, which coincide with the locations of the subband edges, as a function of the electrochemical potential.     

Investigation of bone mineral distribution in Japanese using dual-energy X-ray absorptiometry

To investigate bone mineral distribution in humans, the authors conducted a cross-sectional survey of, and performed bone-density measurements on, 1,310 healthy Japanese ranging in age 5 to 85 years. Eight hundred fifty-eight of the subjects were female, and 452 were male. Arm, leg, and spine bone mineral content (BMC) and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA), and the subjects were divided into 5-year age groups. BMD showed increases with skeletal growth until reaching a peak at 15 to 19 years in females, and 25 to 29 for males. For both sexes the fastest growth to maturity in terms of bone mass values was in the late 20s. Females, though, had higher arm, leg, and spine remodeling rates than males. In premenopausal women no changes in arm, leg or spine BMC and BMD were observed. Postmenopausal women showed an overall reduction in bone mass, most noticeably in the spine. After menopause, women had about 10 years of accelerated loss (1.46%/year). Vertebral BMD values were similar for men and women (1.10 +/- 0.20g/cm2 for males vs. 1.09 +/- 0.14g/cm2 for females, p > 0.05). BMC values were significantly higher in males, and males at all times had a higher arm and leg BMD. There were no significant value differences in either sex for left and right leg BMC and BMD; however, from the age of 15, right arm values were significantly higher likely due to right handedness. For both sexes the order of BMC and BMD was leg, spine, and arm.     

Designing intersections—designing subjectivity: Feminist theory and praxis in a sex discrimination legislation system

This paper looks at the intersections between feminist epistemology, feminist jurisprudence and research on artificial intelligence and the law. It is suggested that feminist theory highlights the role of subjectivity which is ignored in the traditional epistemology of AI systems. This allows AI systems to appear to be “perspectiveless” when they may be tacitly used in a normative role which ignores alternative knowledges. The paper looks at the Cyc system as an example. In developing an expert system to advise on Sex Discrimination law a number of lessons are learned both from the Forms Helper system and more particularly from feminist jurisprudence and from the critique of AI from feminist epistemology.