The propagation of a shock wave into an interstellar medium is investigated by two-dimensional numerical hydrodynamic calculation with cooling, heating and thermal conduction. We present results of the high-resolution two-dimensional calculations to follow the fragmentation due to the thermal instability in a shock-compressed layer. We find that geometrically thin cooling layer behind the shock front fragments into small cloudlets. The cloudlets have supersonic velocity dispersion in the warm neutral medium in which the fragments are embedded as cold condensations. The fragments tend to coalesce and become larger clouds.Comment: 4 pages, 2 figures. ApJL accepte

We investigate the propagation of a shock wave into a warm neutral medium and cold neutral medium by one-dimensional hydrodynamic calculations with detailed treatment of thermal and chemical processes. Our main result shows that thermal instability inside the shock-compressed layer produces a geometrically thin, dense layer in which a large amount of hydrogen molecules is formed. Linear stability analysis suggests that this thermally-collapsed layer will fragment into small molecular cloudlets. We expect that frequent compression due to supernova explosions, stellar winds, spiral density waves, etc., in the galaxy make the interstellar medium occupied by these small molecular cloudlets.

In selected patients with severe emphysema, lung-volume-reduction surgery can improve FEV1, walking distance, and quality of life. Whether it reduces mortality is uncertain.

When dyspnea must be assessed clinically, there are three methods of assessment: the measurement of dyspnea with activities of daily living using clinical dyspnea ratings such as the modified Medical Research Council (MRC), the Baseline Dyspnea Index (BDI), and the Oxygen Cost Diagram (OCD); the measurement of dyspnea during exercise using the Borg scale; to assess the influence of dyspnea on health-related quality of life (HRQoL) using disease-specific questionnaires such as the St. George's Respiratory Questionnaire (SGRQ) and the Chronic Respiratory Disease Questionnaire (CRQ). The purpose of the present cross-sectional study was to clarify relationships between dyspnea ratings and HRQoL questionnaires by applying factor analysis. One hundred sixty-one patients with mild to severe COPD completed pulmonary function tests, progressive cycle ergometer testing for exercise capacity, assessment of dyspnea, HRQoL, anxiety, and depression. Factor analysis demonstrated that the MRC, BDI, OCD, and Activity of the SGRQ, and Dyspnea of the CRQ, were grouped into the same factor, and the frequency distribution histograms of these five measures showed virtually the same distribution. The Borg scale at the end of maximum exercise was found to be a different factor. The MRC, BDI, OCD, and Activity in the SGRQ, and Dyspnea in the CRQ demonstrated the same pattern of correlation with physiologic data, and they had significant relationships with FEV1 (correlation coefficients [Rs] = 0.31 to 0. 48) and maximal oxygen uptake (Rs = 0.46 to 0.60). Disease-specific HRQoL questionnaires, the SGRQ and the CRQ, which contain a specific dimension for evaluating dyspnea, may be substituted for clinical dyspnea ratings in a cross-sectional assessment. Dyspnea rating at the end of exercise may provide further information regarding dyspnea.

With the rapid aging of Japanese society, medical care of the elderly has become an important social issue. Among various disorders manifesting dementia, gait disturbance, and urinary incontinence in the elderly population, normal pressure hydrocephalus (NPH), especially of idiopathic type (iNPH), is becoming noteworthy. The Guidelines for management of iNPH in Japan are created in compliance with the evidence-based medicine methods and published in 2004. This English version is made to show the diagnosis and treatment of iNPH with reference to the socio-medical background in Japan and to promote the international research on iNPH. They propose three diagnostic levels; possible, probable, and definite. They indicate the diagnostic importance of high convexity tightness and dilated sylvian fissure with mild to moderate ventriculomegaly on coronal magnetic resonance imaging. The cerebrospinal fluid tap test is regarded as an important diagnostic test because of its simplicity to perform and high predictability of the shunt efficacy. The use of programmable valves at shunt surgeries is recommended. Flowcharts for diagnosis, preoperative assessment, and prevention for complications of shunt surgery are made to promote a wide use of them.