Setting Priorities in Occupational Health Research in Vietnam

It is well known that silica exposure leads in an experimental model to the development of an acute fibrotic process. In human beings two main observations have already been done: (1) silica exposure is frequently associated with the development of connective tissue disease (CTD), especially progressive systemic sclerosis; (2) 10 to 20% patients with CTD developed pulmonary fibrosis. In this context we report 26 cases of coal miners who presented with clinical, radiological, biological and functional characteristics mimicking idiopathic pulmonary fibrosis (IPF), with or without associated coal worker's pneumoconiosis (CWP). All were men; mean age was 68 +/- 9.2 years. Twenty-three were smokers. Duration of exposure was 28.8 +/- 9.1 years. All the patients had dyspnea (stage III, IV in the NHYA classification) and diffuse crackles. Eleven out of 26 had finger clubbing. Computed tomography showed honeycombing (23 cases), and/or ground glass opacities (6 cases) with bronchiectasis (3 cases) predominant in the lower lobes; 19 had radiological signs of CWP, micronodules (n = 16) and nodules (n = 3) predominant in the upper lobes. BAL exhibited an increased % of neutrophils (11.9 +/- 16.1%). Lung function demonstrated a restrictive pattern (TLC = 73 +/- 15.6% and VC = 80 +/- 18% of predicted values) associated with a decreased DLCO (51.8 +/- 23.6% of predicted values) and hypoxemia (at rest = 66.5 +/- 11.2 mmHg, upon effort = 56 +/- 12 mmHg). Lung biopsies were performed in four cases and demonstrated interstitial fibrosis of intraalveolar septum with an accumulation of immune and inflammatory cells similar to the one described in IPF. The association between IPF and silica exposure with or without associated CWP points out the problem of legal recognition of idiopathic-like pulmonary fibrosis as a complication of the occupational exposure of coal workers.     

Significance of porosity and compliance of microporous, polyurethane-based microarterial vessel on neoarterial wall regeneration

The microporous structure of artificial vascular grafts, which increases compliance and porosity simultaneously, may enhance neoarterial regeneration. In order to differentiate these effects, three models of segmented polyurethane grafts (inner diameter, 1.5 mm; wall thickness, 100 microns) with or without micropores fabricated using an excimer laser ablation technique, were prepared, and their neoarterial regenerative potentials were studied upon implantation: Model I (microporous, permeable, compliant); Model II (smooth-surfaced, impermeable, compliant); and Model III (smooth-surfaced, impermeable, noncompliant). In Models I and II, the pore or groove size (diameter, 100 microns) and pore or groove arrangement were fixed, and consequently their compliances were almost identical. Irrespective of model, the luminal surfaces were coated with benzophenone-derivatized gelatin and subsequently photocured. Twenty grafts (length, 20 mm) of each model were implanted in the aortas of rats. Predetermined implantation periods were 4, 12, and 24 weeks. Total patency rate decreased in the order Model I (100%), II (87%), and III (59%) grafts. All patent grafts were completely endothelialized after 12 weeks of implantation, irrespective of model. After 12- and 24-week implantations, in Model I grafts, the neoarterial wall was thin, and smooth muscle cells (SMCs) were of the contractile phenotype. In Model II grafts, the neoarterial wall exhibited considerable thickening. In Model III grafts, the neoarterial wall exhibited marked thickening, and SMCs were of the synthetic phenotype. The neoarterial wall thickness at the midportion of the grafts after 24 weeks of implantation increased in the order Model I (48 +/- 8 microns), II (146 +/- 87 microns), and III (385 +/- 21 microns) grafts. These results strongly suggest that compliance matching and porosity synergistically resulted in neoarterial wall restoration without appreciable thickening.     

Laurence-Moon-Biedl syndrome (?) and Prader-Willi syndrome (?) in a single family

Mental retardation, hypogonadism, obesity, and abnormal blood sugar regulation were common findings in two siblings. In addition, the 17-year-old female patient showed short stature, muscular hypotonia in infancy, and small hands with tapering fingers suggesting Prader-Willi syndrome, and the 12-year-old male patient showed retinitis pigmentosa, normal height, and normal muscular tonicity suggesting Laurence-Moon-Biedl syndrome, though polydactyly was absent. Possible consideration was discussed.     

Intercalation study and catalysis by lanthanum niobium oxides

For the study of the acidic character of layered perovskite oxide, HLaNb₂O₇ (HLa), the intercalation of water and alcohols was performed and further the HLa was used of dehydration of 1- and 2-butanol as a test reaction. The acidic properties of the HLa was greatly affected by the irreversible water in the interlayer removed in the temperature range of 350°C 00°C. In the presence of water, the intercalation of hydrophilic nalcohols having carbon number below 5 occurred. Dehydration activity of 2-butanol was higher than 1-butanol and produced only n-butenes. On the other hand, butenes and n-butylaldehyde were produced in the reaction of 1-butanol, especially the formation of the latter was predominant at the lower temperature as 200°C 50°C. With raising the heat-treatment temperature of the catalyst its acidity decreased and was almost lost at 500°C. However, the selectivity to n-butylaldehyde increased, indicating that the acidity did not concern to the nbutylaldehyde formation. The reaction behaviors of 1-and 2-butanol on the HLa catalyst were discussed.     

A 3.3-V 12-ns 16-Mb CMOS SRAM

A 16-Mb CMOS SRAM having an access time of 12 ns under a 3.3-V supply has been developed with a 0.4-μm process technology. An address access time of 12 ns has been achieved by an optimized architecture, the use of an automated transistor size optimizer, and a read-bus midlevel preset scheme (RBMIPS). For better yield and efficient testing, an on-chip test circuit with three test modes has been implemented