A major consequence of the invasion of digital media devices with screens equipped with light-emitting diode (LED) into bedrooms exposes the users to ongoing short wavelength (SWL) lighting during the evening and at night when under natural conditions, long wavelength are dominant. Results of several studies reveal a negative physiological, behavioral, and functional outcome of the exposure to SWL artificial light at night (ALAN) from digital media screens. The aims of our study are to assess the relationships between digital media usage, sleep patterns, subjective sleepiness, and attention abilities in adult Israeli citizens compared with Israeli adolescents. We recruited 280 adult participants using convenience sample method, 49% males and 51% females with an age range of 18–82. The participants filled out self-reporting novel and original questionnaires as follows: demographic, general health evaluation, sleep habits, and difficulties by the Pittsburgh Sleep Quality Index (PSQI) and the Karolinska Sleepiness Scale (KSS), prevalence, and usage patterns of digital media devices. Smartphones are the most used digital media device in the evening and after bedtime (the time one gets to sleep in bed). Israeli adults used smartphones for 30 min and TV for about 15 min after bedtime. We noted that excessive exposure to these devices at nighttime was associated with longer sleep latency (r = 0.192, p < 0.01) and decreased sleep hours (r = − 0.143, p < 0.05). Moreover, we found a negative correlation between attention abilities in the morning and the usage time of digital media at nighttime (r = − 0.155, p < 0.01). Exposure to digital screens at evening and nighttime was positively correlated with subjective sleepiness on the KSS (r = 0.135, p < 0.05, and r = 0.261, p < 0.01). To the best of our knowledge, this study is the first to explore the association between digital media screens usage, sleep, and concentration abilities in the Israeli adult.
The effects of pressure on structure and activity of recombinant human acetylcholinesterase (rHuAChE) were investigated up to a pressure of 300 MPa using gel electrophoresis under elevated hydrostatic pressure, fluorescence of bound 8-anilinonaphthalene-1-sulfonate (ANS) and activity measurements following exposure to high pressure. Study of wild-type enzyme and three single mutants (D74N, E202Q, E450A) and one sextuple mutant (E84Q/E292A/D349N/E358Q/E389Q/D390N) showed that pressure exerts a differential action on wild-type rHuAChE and its mutants, allowing estimation of the contribution of carboxylic amino acid side-chains to enzyme stability. Mutation of negatively charged residues D74 and E202 by polar side-chains strengthened heat or pressure stability. The mutation E450A and the sextuple mutation caused destabilization of the enzyme to pressure. Thermal inactivation data on mutants showed that all of them were stabilized against temperature. In conclusion, pressure and thermal stability of mutants provided evidence that the residue E202 is a determinant of structural and functional stability of HuAChE. 相似文献
The relationship between chromosomal nondisjunction and semen quality was studied in two groups of males who differ highly
in their semen quality: 12 individuals with low-quality semen caused by varicocele, and 8 subjects with high-quality semen,
selected from sperm donors for in vitro fertilization. Chromosomal nondisjunction was inferred from the rate of disomy found
in mature sperm cells. To determine the rate of disomy, we applied fluorescence in situ hybridization using satellite-specific
probes for chromosomes 1, 15, 18, X and Y. In sperm cells of males with low-quality semen, the mean rate of disomy for each
of the autosomes and of hetero-disomy for the sex chromosomes (XY) was significantly higher than that observed in the high-quality
semen samples: more than 15-fold higher for chromosomes 1 and 15, and 7-fold higher for chromosomes 18 and XY. Yet, the homo-disomy
rate for each of the sex chromosomes (XX and YY) was almost the same in both types of semen. The large discrepancy between
the low- and high-quality semen in the rate of sex chromosome hetero-disomy versus the similar rate of homo-disomy strongly
suggests that the abnormal chromosomal segregation in meiocytes of males with low-quality semen resulted from chromosomal
nondisjunction at the first meiotic division. The results indicate that men showing poor semen quality are at an increased
risk for meiotic nondisjunction, similar to women at the end of their reproductive years.
Received: 30 June 1997 / Accepted: 17 September 1997 相似文献
The use of electronic devices with light-emitting screens has increased exponentially in the last decade. As a result, humans are almost continuously exposed to unintentional artificial light. We explored the independent and combined effects of two aspects of screen illumination, light wavelength, and intensity, on sleep, its biological regulation, and related functional outcomes. The 2 × 2 repeated-measure design included two independent variables: screen light intensity (low ([LI] versus high [HI]) and wavelength (short [SWL] versus long [LWL]). Nineteen participants (11F, 8M; mean age 24.3 [±2.8] years) underwent four light conditions, LI/SWL, HI/SWL, LI/LWL, and HI/LWL, in counterbalanced order. Each light exposure lasted for two hours (21:00–23:00), following which participants underwent an overnight polysomnography. On each experimental night, oral temperature and urine samples (for melatonin analysis) were collected at multiple time points. Each morning, participants filled out questionnaires and conducted a computerized attention task. Irrespective of light intensity, SWL illumination significantly disrupted sleep continuity and architecture and led to greater self-reported daytime sleepiness. SWL light also altered biological rhythms, subduing the normal nocturnal decline in body temperature and dampening nocturnal melatonin secretion. Light intensity seemed to independently affect sleep as well, but to a lesser degree. Both light intensity and wavelength negatively affected morning attention. In sum, light wavelength seems to have a greater influence than light intensity on sleep and a wide-range of biological and behavioral functions. Given the widespread use of electronic devices today, our findings suggest that screen light exposure at evening may have detrimental effects on human health and performance. 相似文献
Heparanase is an endoglycosidase which cleaves heparan sulfate and hence participates in degradation and remodeling of the extracellular matrix. Importantly, heparanase activity correlated with the metastatic potential of tumor-derived cells, attributed to enhanced cell dissemination as a consequence of heparan sulfate cleavage and remodeling of the extracellular matrix barrier. Heparanase has been characterized as a glycoprotein, yet glycan biochemical analysis was not performed to date. Here, we applied the Qproteometrade mark GlycoArray kit to perform glycan analysis of heparanase, and compared the kit results with the more commonly used biochemical analyses. We employed fibroblasts isolated from patients with I-cell disease (mucolipidosis II), fibroblasts deficient of low density lipoprotein receptor-related protein and fibroblasts lacking mannose 6-phosphate receptor, to explore the role of mannose 6-phosphate in heparanase uptake. Iodinated heparanase has been utilized to calculate binding affinity. We provide evidence for hierarchy of binding to cellular receptors as a function of heparanase concentration. We report the existence of a high affinity, low abundant (i.e., low density lipoprotein receptor-related protein, mannose 6-phosphate receptor), as well as a low affinity, high abundant (i.e., heparan sulfate proteoglycan) receptors that mediate heparanase binding, and suggest that these receptors co-operate to establish high affinity binding sites for heparanase, thus maintaining extracellular retention of the enzyme tightly regulated. 相似文献