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1.
PLoS One ; 17(1): e0261969, 2022.
Article in English | MEDLINE | ID: mdl-35025893

ABSTRACT

During the 2019 novel coronavirus disease (COVID-19) pandemic, many employees have switched to working from home. Despite the findings of previous research that working from home can improve productivity, the scale, nature, and purpose of those studies are not the same as in the current situation with the COVID-19 pandemic. We studied the effects that three stress relievers of the work-from-home environment-company support, supervisor's trust in the subordinate, and work-life balance-had on employees' psychological well-being (stress and happiness), which in turn influenced productivity and engagement in non-work-related activities during working hours. In order to collect honest responses on sensitive questions or negative forms of behavior including stress and non-work-related activities, we adopted the randomized response technique in the survey design to minimize response bias. We collected a total of 500 valid responses and analyzed the results with structural equation modelling. We found that among the three stress relievers, work-life balance was the only significant construct that affected psychological well-being. Stress when working from home promoted non-work-related activities during working hours, whereas happiness improved productivity. Interestingly, non-work-related activities had no significant effect on productivity. The research findings provide evidence that management's maintenance of a healthy work-life balance for colleagues when they are working from home is important for supporting their psychosocial well-being and in turn upholding their work productivity.


Subject(s)
COVID-19/psychology , Pandemics/prevention & control , Adolescent , Adult , Aged , Efficiency/physiology , Female , Health Status , Home Environment , Humans , Male , Middle Aged , SARS-CoV-2/pathogenicity , Surveys and Questionnaires , Work-Life Balance/methods , Young Adult
2.
J Chem Phys ; 155(11): 114901, 2021 Sep 21.
Article in English | MEDLINE | ID: mdl-34551522

ABSTRACT

While proteins have been treated as particles with a spherically symmetric interaction, of course in reality, the situation is rather more complex. A simple step toward higher complexity is to treat the proteins as non-spherical particles and that is the approach we pursue here. We investigate the phase behavior of the enhanced green fluorescent protein (eGFP) under the addition of a non-adsorbing polymer, polyethylene glycol. From small angle x-ray scattering, we infer that the eGFP undergoes dimerization and we treat the dimers as spherocylinders with aspect ratio L/D - 1 = 1.05. Despite the complex nature of the proteins, we find that the phase behavior is similar to that of hard spherocylinders with an ideal polymer depletant, exhibiting aggregation and, in a small region of the phase diagram, crystallization. By comparing our measurements of the onset of aggregation with predictions for hard colloids and ideal polymers [S. V. Savenko and M. Dijkstra, J. Chem. Phys. 124, 234902 (2006) and Lo Verso et al., Phys. Rev. E 73, 061407 (2006)], we find good agreement, which suggests that the behavior of the eGFP is consistent with that of hard spherocylinders and ideal polymers.


Subject(s)
Colloids , Polymers , Protein Aggregates , Proteins , Colloids/chemistry , Crystallization , Polymers/chemistry , Proteins/chemistry
3.
Article in English | MEDLINE | ID: mdl-33808764

ABSTRACT

In this paper, we propose a latent pandemic space modeling approach for analyzing coronavirus disease 2019 (COVID-19) pandemic data. We developed a pandemic space concept that locates different regions so that their connections can be quantified according to the distances between them. A main feature of the pandemic space is to allow visualization of the pandemic status over time through the connectedness between regions. We applied the latent pandemic space model to dynamic pandemic networks constructed using data of confirmed cases of COVID-19 in 164 countries. We observed the ways in which pandemic risk evolves by tracing changes in the locations of countries within the pandemic space. Empirical results gained through this pandemic space analysis can be used to quantify the effectiveness of lockdowns, travel restrictions, and other measures in regard to reducing transmission risk across countries.


Subject(s)
COVID-19 , Pandemics , Communicable Disease Control , Humans , SARS-CoV-2 , Space Simulation
4.
Article in English | MEDLINE | ID: mdl-23533460

ABSTRACT

Introduction. Hypertension in association with diabetes (DM), renal impairment (RI), and left ventricular hypertrophy (LVH) increases the risk of future cardiovascular events. We hypothesize, traditional herbal medicines Danshen and Gegen (D&G) have beneficial effects on atherogenesis in these high-risk hypertensive subjects. Subjects and Methods. 90 asymptomatic hypertensive subjects associated with LVH (63.3%), DM (62.2%), or RI (30%) were randomized to receive D&G herbal capsules 1 gm/day, 2 gm/day, or identical placebo capsules in double-blind and parallel fashion for 12 months. Brachial flow-mediated dilation (endothelium-dependent dilation, FMD) and carotid intima-media thickness (IMT) were measured by ultrasound. All data were analyzed using the Statistical Package for Social Sciences in Windows 16.0. Results. Their mean age was 55 ± 8 years, and 74.4% were male. After 12 months of adjunctive therapies and compared with baseline, there were no significant changes in blood pressure, heart rate, hematological, glucose, and creatinine profiles in both placebo and D&G groups. FMD improved significantly during D&G (P = 0.0001) and less so after placebo treatment (P = 0.001). There was a mild but significant decrease in carotid IMT after D&G (P < 0.001) but no significant changes after placebo. A trend of better improvement in FMD after higher versus lower D&G dosages was seen. D&G were well tolerated, with no significant adverse events or blood biochemistry changes. Conclusion. D&G adjunctive treatment was well tolerated and significantly improved atherogenesis in high-risk hypertensive patients, with potential in primary atherosclerosis prevention.

5.
Int J Cardiol ; 128(2): 172-7, 2008 Aug 18.
Article in English | MEDLINE | ID: mdl-18199502

ABSTRACT

BACKGROUND: Both active and passive smoking are prevalent in China but cardiovascular diseases were less prevalent in the past. We studied the current relationship between surrogate atherosclerosis markers and smoking in Chinese. METHODS: Endothelium-dependent flow-mediated dilation (FMD) of brachial artery and carotid intima-media thickness (IMT) were measured non-invasively by ultrasound in 616 apparently healthy Chinese (23% smokers), recruited from greater China and the USA. RESULTS: The Chinese smokers had significantly impaired FMD (7.0+/-2.3 vs. 8.2+/-2.5%, p<0.001) and endothelium-independent vasodilation (GTN, 17.4+/-3.9 vs. 18.7+/-4.1%, p=0.001) and thicker IMT (0.61+/-0.13 vs. 0.58+/-0.12 mm, p=0.025). 91% of the smokers were male. Both endothelium-dependent (6.9+/-2.2 vs. 8.0+/-2.5%, p<0.001) and independent (17.3+/-3.5 vs. 18.2+/-3.7%, p=0.047) vasodilation were significantly lower in the male smokers than non-smokers, although their age and cholesterol levels were lower. FMD-to-GTN ratio in the smokers were lower (0.41+/-0.12 vs. 0.45+/-0.13, p=0.005). Multivariate analyses confirmed an independent adverse impact of smoking on vascular functions. There were no consistent interactions between subject location and impact of smoking on FMD and IMT. CONCLUSION: In these apparently healthy native and overseas Chinese subjects, smoking is adversely associated with endothelial dysfunction and arterial wall thickening, with serious implication in atherosclerosis prevention.


Subject(s)
Asian People , Atherosclerosis/ethnology , Carotid Arteries/pathology , Endothelium, Vascular/physiopathology , Muscle, Smooth, Vascular/physiopathology , Smoking/adverse effects , Adolescent , Adult , Aged , Asian/statistics & numerical data , Asian People/statistics & numerical data , Atherosclerosis/etiology , Atherosclerosis/physiopathology , Atherosclerosis/prevention & control , Biomarkers , Case-Control Studies , China/epidemiology , China/ethnology , Female , Hong Kong/epidemiology , Humans , Linear Models , Male , Middle Aged , Multivariate Analysis , Risk Factors , San Francisco/epidemiology , Tunica Intima/physiopathology
7.
Food Chem Toxicol ; 33(6): 507-13, 1995 Jun.
Article in English | MEDLINE | ID: mdl-7797178

ABSTRACT

The dermal response of three strains of mice (ICR, C3H and B6C3F1) exposed to repeated doses of 0, 1 or 4% acrylic acid was examined over 13 wk. Microscopic and gross changes to the skin were classified as being indicative of exceeding the maximum tolerated dose (MTD), reaching the MTD, or tolerating the dose based on proposed MTD guidelines established in US Environmental Protection Agency (EPA) Workshops on dermal carcinogenesis bioassays. A significant number of animals in all three strains with repeated exposure to 4% acrylic acid experienced skin irritation that was classified as having reached or exceeded the MTD compared with animals exposed to either 1% acrylic acid or the 0% acrylic acid acetone control. These results were observed within the first 3 wk of exposure, but there was some accommodation to irritation by 8 wk of exposure. Microscopic findings provided a more sensitive index for exceeding MTD than gross observations taken only at autopsy, but generally correlated well for MTD if gross observations were taken at regular intervals during treatment. That is, to set MTD, gross observations could be used if taken over the entire course of the exposure, but using microscopic findings was generally a more reliable or sensitive measure. EPA guidelines suggest that it is inappropriate to conduct a dermal bioassay at concentrations that exceed the MTD. Acrylic acid at 4% in acetone clearly exceeded the MTD based on microscopic or gross observation criteria. At 4%, strain differences were evident by gross observation only, with the ICR strain being less susceptible to irritation than C3H or B6C3F1 strains. These strain differences were not apparent with microscopic examination. Acrylic acid at 1% in acetone, although demonstrating signs of minimal irritation, was fairly well tolerated by all mice in all strains. Thus, acrylic acid at 1% in acetone, one-quarter of the concentration that was in clear excess of the MTD, would be the appropriate dose concentration for lifetime skin studies based on MTD criteria.


Subject(s)
Acrylates/toxicity , Administration, Topical , Animals , Body Weight/drug effects , Female , Male , Mice , Mice, Inbred C3H , Mice, Inbred ICR , Mice, Inbred Strains , Skin/drug effects , Skin/pathology , Skin Tests , Species Specificity , Time Factors
8.
South Med J ; 87(5): S23-5, 1994 May.
Article in English | MEDLINE | ID: mdl-8178198

ABSTRACT

Skeletal development in average healthy individuals is maximal at age 25 in women and at age 30 to 35 in men. However, there are significant racial differences, skeletal mass being greater in black than in white individuals. This difference appears best accounted for by increased muscle mass in blacks. Bed rest, immobilization, weightlessness (as in space flights), and aging induce a decrease in skeletal mass. The degree of osteopenia in the elderly depends partly on skeletal development during formative years and can be prevented from becoming severe by maintaining good nutritional status (calcium, vitamin D, protein) and physical activity. Maintenance or actual increase in muscle mass is a desired effect of appropriate physical activity, but excessive physical exercise may induce estrogen deficiency and menstrual irregularities in premenopausal women. In addition to diet and exercise, pharmacologic therapy (estrogens, androgens, diphosphonates, or calcitonin) is indicated in patients with significant osteoporosis.


Subject(s)
Aging/physiology , Bone and Bones/physiopathology , Exercise/physiology , Absorptiometry, Photon , Adult , Bone Density , Cushing Syndrome/complications , Diet , Female , Humans , Male , Middle Aged , Osteoporosis/diagnostic imaging , Osteoporosis/pathology , Osteoporosis/physiopathology , Racial Groups
10.
Food Chem Toxicol ; 30(6): 505-15, 1992 Jun.
Article in English | MEDLINE | ID: mdl-1500036

ABSTRACT

Acrylic acid was tested for gene mutations in the in vitro CHO/HGPRT assay, for chromosome aberrations in CHO cells in culture, and for potential to induce unscheduled DNA synthesis in rat hepatocytes in culture. In vivo assays performed included the Drosophila sex-linked recessive lethal assay by both the feeding and injection routes, the in vivo cytogenetic assay in rat bone marrow cells after both a 1-day and 5-day oral dosing regimen, and a dominant lethal assay in mice by both an acute and 5-day dosing regimen. All results were negative (non-mutagenic) except for the in vitro chromosome aberration assay. This latter result is consistent with the previously reported possible clastogenic activity suggested by the results of the mouse lymphoma L5178Y TK locus assay in which a predominance of small-colony mutants was observed (Moore et al., Environmental and Molecular Mutagenesis 1988, 11, 49-63). The rapid clearance of acrylic acid in animals and the weight of evidence of genetic toxicity testing, including negative in vivo data in both somatic and germ cells, indicate a lack of genetic toxicity of acrylic acid in vivo.


Subject(s)
Acrylates/toxicity , Chromosome Aberrations , DNA Damage , Mutagens/toxicity , Animals , Body Weight/drug effects , Bone Marrow/drug effects , Bone Marrow Cells , CHO Cells , Cells, Cultured , Cricetinae , Drosophila , Female , Hydrogen-Ion Concentration , Liver/cytology , Liver/drug effects , Male , Mice , Mutagenicity Tests , Mutation , Osmolar Concentration , Rats , Rats, Inbred Strains
11.
Food Chem Toxicol ; 29(7): 453-8, 1991 Jul.
Article in English | MEDLINE | ID: mdl-1894211

ABSTRACT

Cellulose acetate was administered by way of a dietary admixture to Sprague-Dawley rats (20/sex/group) at dose levels of 0, 500, 2500 and 5000 mg/kg body weight/day for 94-96 days. Physical observations, body weight and food consumption measurements were made before testing and throughout the study. Ophthalmoscopic examinations were conducted on all animals before testing and just prior to study termination. Haematology, clinical chemistry and urinalysis were performed at 1.5 and 3 months on 10 animals/sex/group. After 3 months of treatment the animals were killed, terminal body weights and organ weights were measured and ratios calculated. Histopathological examination of tissues from the control and high-dose groups was conducted. The evaluation of physical observations, ophthalmology, body weight, food consumption, haematology, clinical chemistry, organ-to-body-weight ratios, gross pathology and histopathology revealed no evidence of an adverse effect related to treatment with cellulose acetate.


Subject(s)
Cellulose/analogs & derivatives , Administration, Oral , Animals , Blood Cells/drug effects , Blood Chemical Analysis , Body Weight/drug effects , Cellulose/administration & dosage , Cellulose/toxicity , Eating/drug effects , Female , Male , Ophthalmoscopy , Organ Size/drug effects , Rats , Rats, Inbred Strains
12.
Drug Chem Toxicol ; 14(3): 243-56, 1991.
Article in English | MEDLINE | ID: mdl-1935705

ABSTRACT

An acute inhalation toxicity study in several species of animals with an ethylene oxide/propylene oxide copolymer (EO/PO) having a molecular weight of 4000 [UCON-50-HB-5100, CAS #9038-95-3] was designed to determine if any species variation could be shown. Species tested included: rats, mice, hamsters, guinea pigs, and dogs. The test material was administered as a respirable liquid aerosol for 4 hours at target concentrations of 50, 100, 200, and 500 mg/m3. A vehicle control group was exposed to a distilled water aerosol. The 4 hours LC50's were calculated to be 147 mg/m3 [rats], 174 mg/m3 [mice], 293 mg/m3 [guinea pigs] and 511 mg/m [hamsters]. The dog LC50 was determined to be greater than 500 mg/m3 since all the test animals survived exposure to this concentration. These values show that rats and mice were the most sensitive species with a declining response in guinea pigs, hamsters and dogs. Lung weights were increased at all exposure concentrations in rats, mice and hamsters. Lung weights were increased in guinea pigs at exposure concentrations of 100 mg/m3 and above. Lung weights in dogs were increased only at the 500 mg/m3 exposure concentration. Significant pathological changes were limited to the lungs and were more common in animals which died prior to scheduled sacrifice. Grossly, these lung changes consisted of red discoloration, edema, emphysema, and surface irregularities. Microscopic findings in the lungs included acute congestion and hemorrhage and, less commonly, acute interstitial inflammation.


Subject(s)
Epoxy Compounds/toxicity , Ethylene Oxide/toxicity , Polymers/toxicity , Administration, Inhalation , Animals , Body Weight/drug effects , Cricetinae , Dogs , Dose-Response Relationship, Drug , Guinea Pigs , Male , Mesocricetus , Mice , Particle Size , Rats , Rats, Inbred Strains
14.
Endocrinol Metab Clin North Am ; 19(4): 839-49, 1990 Dec.
Article in English | MEDLINE | ID: mdl-2081514

ABSTRACT

In this brief review of various hypercalcemic disorders and the likelihood of renal calculus formation, it is clearly evident that renal calculi occur much more often in hyperparathyroidism than in the other hypercalcemic states. Dystrophic calcification and nephrocalcinosis are common to all of the hypercalcemic disorders, including hyperparathyroidism, when the hypercalcemia is marked and the limit of solubility of calcium and phosphate in serum is approached. Interestingly, in sarcoidosis there are calcium oxalate crystals in variously distributed sarcoid granuloma, and the renal calculi are composed of calcium oxalate. By contrast, in hyperparathyroidism, the calculi composed of calcium phosphate predominate. This indicates a subtle and as yet undefined alteration in oxalate metabolism in sarcoidosis. An increase in urine pH occurs in hyperparathyroidism, and this enhances formation of crystalline calcium phosphate. However, the striking disparity between the frequency of calculus formation in hyperparathyroidism and that in other hypercalcemic disorders, several of which may be of relatively long duration, suggests that there indeed may be increased promoters of crystal formation in the urine of hyperparathyroid patients.


Subject(s)
Hypercalcemia/complications , Urinary Calculi/etiology , Diagnosis, Differential , Hyperparathyroidism/complications , Hyperparathyroidism/diagnosis , Hyperparathyroidism/therapy , Multiple Myeloma/complications , Multiple Myeloma/diagnosis , Sarcoidosis/complications , Sarcoidosis/diagnosis , Sarcoidosis/therapy , Vitamin D/poisoning
15.
J Am Geriatr Soc ; 38(8): 884-8, 1990 Aug.
Article in English | MEDLINE | ID: mdl-2387952

ABSTRACT

Serum concentrations of parathyroid hormone are frequently increased in elderly subjects. How much this increase may contribute to the development of osteoporosis in such subjects is unknown. Long-standing hypoparathyroidism has been reported to be accompanied by an increase in skeletal density. In seven consecutive women, aged 40 to 83 years, with hypoparathyroidism of at least 18 years duration, the mineral density in the lumbar vertebrae was measured by quantitative computed tomography (QCT) and dual photon absorptiometry (DPA). In these subjects, the bone mineral density by dual photon absorptiometry was 1.4 to 6.2 standard deviations above mean values for age-matched normal women. However, the mineral density of vertebral trabecular bone as determined by quantitative computed tomography was only slightly increased above values reported for normal women. The differences between the values determined by dual photon absorptiometry and quantitative computed tomography indicate that most of the increase in mineral density was a reflection of increased cortical bone. Roentgenograms of the metacarpals did not reveal consistent differences between normals and the hypoparathyroid subjects. These findings suggest the possibility that control of parathyroid function might be of value in treating osteoporotic patients.


Subject(s)
Aging/physiology , Hypoparathyroidism/physiopathology , Osteoporosis/physiopathology , Absorptiometry, Photon , Adult , Aged , Aged, 80 and over , Bone Density/drug effects , Bone Density/physiology , Estrogens/pharmacology , Female , Humans , Lumbar Vertebrae/diagnostic imaging , Lumbar Vertebrae/drug effects , Middle Aged , Radionuclide Imaging , Tomography, X-Ray Computed
16.
J Fla Med Assoc ; 76(12): 1035-6, 1989 Dec.
Article in English | MEDLINE | ID: mdl-2600569

ABSTRACT

Several years may be required for development of clinically evident osteomalacia in previously healthy subjects deprived of exposure to sunlight or enriched dietary sources of vitamin D. In a survey of residents of a 120 bed VA nursing home who had been patients there for two to six years, 17 were found to have x-ray or laboratory findings suggestive of the presence of vitamin D deficiency. Bone biopsy in eight of these 17 patients revealed definite osteomalacia in three patients. Thus, vitamin D deficiency may develop in confined, nonvitamin D fortified patients in Florida just as in more northern climes. Daily exposure for 30 minutes to sunshine or oral administration of 2.5 mg of vitamin D2 or D3 twice yearly has been recommended to prevent deficiency of this vitamin.


Subject(s)
Nursing Homes , Vitamin D Deficiency/diagnosis , Aged , Florida , Humans , Hydroxycholecalciferols/blood , Osteomalacia/blood , Osteomalacia/diagnosis , Vitamin D Deficiency/blood
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