RESUMO
Near-infrared spectroscopy (NIR), a nondestructive analytical technique, was employed for the simultaneous determination of the concentrations of glucose and lactic acid in peritoneal dialysis solutions. Solutions were placed in a near-infrared spectrophotometer and the absorbance at wavelengths between 400 and 2500 nm was measured at 2 nm intervals. To obtain calibration equations, multiple linear regression (MLR) was carried out on the NIR spectral data and on the glucose and lactic acid concentrations obtained by enzymatic methods using a calibration sample set. The value of the simple correlation coefficient (r) was 0.996 when using a wavelength of 2270 nm for glucose. The value of the multiple correlation coefficient (R) for lactic acid was 0.997 when using wavelengths of 1688 and 1268 nm. To validate the calibration equations obtained, glucose and lactic acid concentrations in a prediction sample set which was not used for calibration were calculated using the calibration equation and compared with the concentrations measured by the enzymatic method. Excellent agreement between the results of the enzymatic method and of NIR was observed for both constituents. Concentrations of glucose and lactic acid in the peritoneal dialysis solutions were analyzed simultaneously by NIR. The procedure for NIR was simple, and the operation time required to determine the concentrations was a few minutes. These results indicate that NIR may be a useful method for monitoring of the production of peritoneal dialysis solutions.
RESUMO
In a compost fermentation of soybean-curd (tofu) refuse, the effects of the moisture content of the compost on the compost reaction were studied. The moisture content of the compost was a very important factor for good fermentation. Near-infrared spectroscopy (NIRS) was applied to the determination of the moisture content of the compost. The reflected rays in the wavelength range between 400 and 2500 nm were measured at 2 nm intervals. The absorption of water was observed at three wavelengths, 960, 1406 and 1888 nm. To formulate a calibration equation, a multiple linear regression analysis was carried out between the near-infrared spectral data at 960 nm (sample number, n = 50) and on the moisture content obtained using a drying method. The values of the simple correlation coefficient and the standard error of calibration were 0.987 and 1.33%, respectively. To validate the calibration equation obtained, the moisture content in the prediction sample set (n = 35) not used for formulating the calibration equation was calculated using the calibration equation, and compared with the values obtained using the drying method. Good agreement was observed between the results of the drying method and those of the NIRS method. The simple correlation coefficient and standard error of prediction were 0.979 and 1.85%, respectively. Then, the NIRS method was applied to a practical situation in which the moisture content was measured and controlled during the compost fermentation, and good results were obtained. The study indicates that NIRS is a useful method for measurement and control of the moisture content in the compost of soybean-curd refuse.
RESUMO
The nonapeptide leucinostatin A (LSA) inhibited syncytium formation without profoundly affecting HN glycoprotein synthesis in Newcastle disease virus (NDV)-infected BHK cells. At similar doses of LSA, cytopathic effect and infectious virus production were suppressed in vesicular stomatitis virus (VSV)-infected BHK cells. Blockade by LSA of cell surface expression of NDV-HN and VSV-G glycoproteins was demonstrated, accompanied by intracellular accumulation of these virus glycoproteins. LSA acts as an inhibitor of mitochondrial F-type H(+)-translocating ATPase, a key enzyme in the generation of ATP, but its action against cell surface expression of virus glycoproteins was independent of the depletion of intracellular ATP. LSA also acts as an ionophore, but its action on intoxication by ricin and diphtheria toxin was different from that of monensin. This novel action of LSA is expected to be useful in investigation of the mechanism of intracellular trafficking of proteins.
