NROM: A novel localized trapping, 2-bit nonvolatile memory cell

This paper presents a novel flash memory cell based on localized charge trapping in a dielectric layer and on a new read operation. It is based on the storage of a nominal ~400 electrons above a n⁺/p junction. Programming is performed by channel hot electron injection and erase by tunneling enhanced hot hole injection. The new read methodology is very sensitive to the location of trapped charge above the source. This single device cell has a two physical bit storage capability. The cell shows improved erase performances, no over erase and erratic bit issues, very good retention at 250°C, and endurance up to 1M cycles. Only four masks are added to a standard CMOS process to implement a virtual ground array. In a typical 0.35 μm process, the area of a bit is 0.315 μm² and 0.188 μm² in 0.25 μm technology. All these features and the small cell size compared to any other flash cell make this device a very attractive solution for all NVM applications     

The use of composite materials in modern orthopaedic medicine and prosthetic devices: A review

The use of fibre reinforced composite materials for biomedical purposes is reviewed. The development of polymer composite materials has, in recent years, led to technological advances across a wide range of applications in modern orthopaedic medicine and prosthetic devices. Composites typically possess a superior strength to weight characteristic compared to monolithic materials and offer excellent biocompatibility. They are, therefore, favourable for both hard- and soft-tissue applications as well as the design of prostheses. In particular, the development of specifically designed carbon fibre sports prostheses now allows lower-limb amputees to actively participate in competitive sports. Sensory feedback systems, porous composite materials for tissue engineering and functional coatings for metallic implants are further developments anticipated to be introduced in next generation orthopaedic medicine.     

Genomic organization, fine-mapping, and expression of the human islet-brain 1 (IB1)/c-Jun-amino-terminal kinase interacting protein-1 (JIP-1) gene

Islet-brain 1 (IB1), a regulator of the pancreatic beta-cell function in the rat, is homologous to JIP-1, a murine inhibitor of c-Jun amino-terminal kinase (JNK). Whether IB1 and JIP-1 are present in humans was not known. We report the sequence of the 2133-bp human IB1 cDNA, the expression, structure, and fine-mapping of the human IB1 gene, and the characterization of an IB1 pseudogene. Human IB1 is 94% identical to rat IB1. The tissue-specific expression of IB1 in human is similar to that observed in rodent. The IB1 gene contains 12 exons and maps to chromosome 11 (11p11.2-p12), a region that is deleted in DEFECT-11 syndrome. Apart from an IB1 pseudogene on chromosome 17 (17q21), no additional IB1-related gene was found in the human genome. Our data indicate that the sequence and expression pattern of IB1 are highly conserved between rodent and human and provide the necessary tools to investigate whether IB1 is involved in human diseases.     

Separating photocurrent and injected current contributions to the organic magnetoresistance

The magnetoresistance in the photocurrent and injected current of an organic device has been studied. When such a device is illuminated under bias, both photo-generated charges and electrically injected carriers will contribute to the current. We used a magnetic field modulation to successfully remove the time-dependent change in the current. This was combined with a modulation of the intensity of the illumination to separately measure the effects of the photocurrent. At low bias, without illumination no magnetoconductance (MC) is observed in leakage current, while with illumination an MC is observed due to the photo-generated charges. With increasing voltage, as electrical charge injection starts, the width of the MC curves as a function of magnetic field of the photocurrent remains constant and is larger than the curve observed for the electrically injected current, even when both currents are present. This result shows that the contributions from the photocurrent and the injected current cannot be combined, but should be treated separately.     

Segmental antigen challenge increases fibronectin in bronchoalveolar lavage fluid

Fibronectin may contribute to asthma pathogenesis by recruitment and activation of inflammatory cells, and by promotion of subepithelial fibrosis. Fibronectin is produced by several types of airway cells, including epithelial cells, fibroblasts, and alveolar macrophages. To test the hypothesis that antigen-induced airway inflammation is associated with increased local generation of fibronectin, segmental bronchoprovocation (SBP) with antigen and saline was performed in 17 atopic patients. Bronchoalveolar lavage (BAL) was performed at 5 min and 48 h after segmental challenge with saline or antigen. Fibronectin concentrations in BAL fluid, measured by enzyme-linked immunosorbent assay (ELISA), increased more than 5-fold 48 h after antigen challenge (65 [47 to 110] versus 407 [240 to 697] ng/ml, median and 25 to 75% interquartiles, p < 0.05). Fibronectin concentrations 48 h after antigen challenge correlated with histamine concentrations 5 min after antigen challenge and numbers of eosinophils, neutrophils, macrophages, and total cells in BAL fluid 48 h after antigen challenge. BAL was more enriched in fibronectin 48 h after challenge than would be predicted solely from increased permeability of plasma proteins. Western blot analysis showed that fibronectin in BAL fluid was largely intact and contained the extra domain-A (ED-A) splice variant of cellular fibronectin, indicative of local production. We conclude that antigen challenge in atopic subjects causes increased production of fibronectin by airway cells and speculate that this response may contribute to airway remodeling in allergic inflammation.     

Insulin receptors are widely distributed in human brain and bind human and porcine insulin with equal affinity

Insulin receptors differing structurally from those in other tissues have been demonstrated in brain from many species. Subtle differences in binding properties have been reported between insulin receptors in brain and other tissues, including differences in affinity of pig brain receptors for human and porcine insulin. Insulin binding has been demonstrated in human cerebral cortex, but insulin binding has not been characterized in other areas of human brain. We have studied the binding of 125I labelled human insulin, and its displacement by unlabelled human and porcine insulin, in homogenates prepared from human hypothalamus, cerebral cortex and cerebellum obtained post-mortem from eight non-diabetic subjects. Specific binding was demonstrated in all brain regions studied, and displacement curves obtained with unlabelled human and porcine insulin were identical. By contrast, unlabelled insulin-like growth factor-1 did not significantly displace 125I labelled human insulin over the same concentration range. We therefore conclude that insulin receptors are widely distributed in human brain and do not differ in their affinity for human and porcine insulin.     

Managed obstetrical care

BACKGROUND: Infertility is common in Africa, but virtually no data exist on HIV prevalence among infertile women. Mainly anthropological studies in Africa have shown that infertile women have higher risks of marital instability and possibly also have more sexual partners than fertile women. METHOD: This study was conducted in a hospital in northwest Tanzania during 1994 and 1995. Women presenting themselves with infertility problems to the outpatient clinic were interviewed, examined and blood was drawn. Women who came to deliver in the hospital, excluding primiparae, were taken as a control group. The analysis was limited to women > or = 24 years. In total 154 infertile and 259 fertile women were included in the study. RESULTS: HIV prevalence was markedly higher among infertile women than among fertile women: 18.2% and 6.6% respectively (adjusted odds ratio [OR] for age, residence and occupation 2.7; 95%-confidence interval [CI]: 1.4-5.3). Data on past sexual behaviour showed that infertile women had more marital breakdowns, more lifetime sexual partners and a higher level of exposure to sexually transmitted diseases (STD). CONCLUSION: Women with fertility problems appear to have higher HIV prevalence, which justifies more attention for such women in the context of AIDS programmes. In addition, caution is needed when using sentinel surveillance data from antenatal clinics to monitor HIV prevalence.