Structure and Properties of Poly(ethylene terephthalate) Fiber Webs Prepared via Laser-Electrospinning and Subsequent Annealing Processes

Melt-electrospinning is an eco-friendly method for producing ultra-fine fibers without using any solvent. We prepared webs of poly(ethylene terephthalate) (PET) through melt-electrospinning using CO₂ laser irradiation for heating. The PET webs comprised ultra-fine fibers of uniform diameter (average fiber diameter = 1.66 μm, coefficient of variation = 19%). The co-existence of fibers with high and low molecular orientation was confirmed through birefringence measurements. Although the level of high orientation corresponded to that of commercial highly oriented yarn, crystalline diffraction was not observed in the wide-angle X-ray diffraction (WAXD) analysis of the webs. The crystallinity of the webs was estimated using differential scanning calorimetry (DSC). The fibers with higher birefringence did not exhibit any cold crystallization peak. After annealing the web at 116 °C for 5 min, a further increase in the birefringence of the fibers with higher orientation was observed. The WAXD results revealed that the annealed webs showed crystalline diffraction peaks with the orientation of the c-axis along the fiber axis. In summary, the formation of fibers with a unique non-crystalline structure with extremely high orientation was confirmed.     

Relationship between depression and risk of malnutrition among community-dwelling young-old and old-old elderly people

Objectives: This study explores the association between nutritional status and depression among healthy community-dwelling young-old (aged 65–74) and old-old elderly (aged 75 and older).

Method: A cross-sectional design was implemented. A total of 274 community-dwelling older individuals (142 young-old; 132 old-old) were assessed using the Geriatric Depression Scale (GDS), Mini-Nutritional Assessment Short-Form (MNA-SF) and Life-Space Assessment. Logistic regression analysis was used to determine if depression was independently associated with risk of malnutrition, stratified by age (young-old vs. old-old).

Results: In the logistic regression model for young-old, being at risk of malnutrition (MNA-SF (≦11) was strongly associated with depression (GDS (≧5;) (likelihood ratio ν?=?6.26; 95% confidence interval [CI]: 1.91–20.49). In contrast, in the old-old group, the model was not statistically significant.

Conclusion: Depression and nutritional status were strongly correlated in young-old but not in old-old community-dwelling elderly. This study reveals that not only the factors correlated with but also the symptoms of depression may vary among different age stratifications of the elderly.     

Improved Orange and Red Ca2+ Indicators and Photophysical Considerations for Optogenetic Applications

相似文献   

Immobilization-induced hypersensitivity associated with spinal cord sensitization during cast immobilization and after cast removal in rats

This study examined mechanical and thermal hypersensitivity in the rat hind paw during cast immobilization of the hind limbs for 4 or 8 weeks and following cast removal. Blood flow, skin temperature, and volume of the rat hind paw were assessed in order to determine peripheral circulation of the hind limbs. Sensitization was analyzed by measuring the expression of the calcitonin gene-related peptide (CGRP) in the spinal dorsal horn following cast immobilization. Two weeks post immobilization, mechanical and thermal sensitivities increased significantly in all rats; however, peripheral circulation was not affected by immobilization. Cast immobilization for 8 weeks induced more serious hypersensitivity compared to cast immobilization for 4 weeks. Moreover, CGRP expression in the deeper lamina layer of the spinal dorsal horn increased in the rats immobilized for 8 weeks but not in those immobilized for 4 weeks. These findings suggest that immobilization-induced hypersensitivity develops during the immobilization period without affecting peripheral circulation. Our results also highlight the possibility that prolonged immobilization induces central sensitization in the spinal cord.