Distinct contributions of muscle mass and strength stratified by nutritional status to physical activity in patients with chronic obstructive pulmonary disease.

BACKGROUND: Physical activity is one of the most important prognostic factors for patients with chronic obstructive pulmonary disease (COPD). Physical activity correlates significantly with skeletal muscle mass and strength. Pulmonary rehabilitation has been conducted to improve physical activity, but its effectiveness has been inconsistent. Nutritional status is also related to physical activity in patients with COPD. The relationships between skeletal muscle mass, strength, and nutritional status evaluated using the Mini Nutritional Assessment Short Form (MNA-SF) were investigated. How nutritional status alters the relationships between physical activity, exercise capacity, skeletal muscle mass, and strength was also investigated. METHODS: This retrospective, cross-sectional study enrolled 81 outpatients with COPD. In all patients, physical activity, exercise capacity, body composition assessment, and MNA-SF were assessed. The relationships between physical activity, exercise capacity, skeletal muscle mass, and strength were examined according to the MNA-SF. RESULTS: The MNA-SF high group had significantly higher skeletal muscle mass than the MNA-SF low group when skeletal muscle strength was the covariate. In the MNA-SF low group, physical activity positively correlated with skeletal muscle mass. In the MNA-SF high group, physical activity positively correlated with skeletal muscle strength. CONCLUSIONS: This study showed that the nutritional status of patients with COPD alters the relationship between physical activity and skeletal muscle mass or strength. Optimizing rehabilitation with nutrition interventions according to nutritional status might improve physical activity in patients with COPD.

In situ observation of a hydrogel-glass interface during sliding friction.

Direct observation of hydrogel contact with a solid surface in water is indispensable for understanding the friction, lubrication, and adhesion of hydrogels under water. However, this is a difficult task since the refractive index of hydrogels is very close to that of water. In this paper, we present a novel method to in situ observe the macroscopic contact of hydrogels with a solid surface based on the principle of critical refraction. This method was applied to investigate the sliding friction of a polyacrylamide (PAAm) hydrogel with glass by using a strain-controlled parallel-plate rheometer. The study revealed that when the compressive pressure is not very high, the hydrogel forms a heterogeneous contact with the glass, and a macro-scale water drop is trapped at the soft interface. The pre-trapped water spreads over the interface to decrease the contact area with the increase in sliding velocity, which dramatically reduces the friction of the hydrogel. The study also revealed that this heterogeneous contact is the reason for the poor reproducibility of hydrogel friction that has been often observed in previous studies. Under the condition of homogeneous full contact, the molecular origin of hydrogel friction in water is discussed. This study highlights the importance of direct interfacial observation to reveal the friction mechanism of hydrogels.

Response of spinach and komatsuna to biogas effluent made from source-separated kitchen garbage.

Recycling of kitchen garbage is an urgent task for reducing public spending and environmental burdens by incineration and/or landfill. There is an interesting regional effort in Ogawa, Saitama prefecture, Japan, in which source-separated kitchen garbage is anaerobically fermented with a biogas plant and the resultant effluent is used as a quick-release organic fertilizer by surrounding farmers. However, scientific assessments of fertilizer values and risks in the use of the effluent were lacking. Thus, a field experiment was conducted from 2003 to 2004 in Tohoku National Agricultural Research Center to grow spinach (Spinacia oleracea L.) and komatsuna (Brassica rapa var. perviridis L. H. Bailey) for evaluating the fertilizer value of the kitchen garbage effluent (KGE), nitrate, coliform group (CG), Escherichia coli, fecal streptococci (FS), and Vibrio parahaemolyticus concentrations of KGE and in the soil and the plant leaves. A cattle manure effluent (CME) and chemical fertilizers (NPK) were used as controls. Total nitrogen (N) and ammonium N concentrations of the KGE were 1.47 and 1.46 g kg(-1), respectively. The bacteria tested were detected in both biogas effluents in the order of 2 to 3 log CFU g(-1), but there was little evidence that the biogas effluents increased these bacteria in the soil and the plant leaves. At the rate of 22 g N m(-2), yield, total N uptake, apparent N recovery rate, and leaf nitrate ion concentration at harvest of spinach and komatsuna in the KGE plot were mostly comparable to those in the NPK and CME plots. We conclude that the KGE is a quick-release N fertilizer comparable to chemical fertilizers and does not cause contamination of CG, E. coli, FS, or V. parahaemolyticus in the soil and spinach and komatsuna leaves.