Binuclear Manganese(III) Complexes as Electron Donors in D1/D2/Cytochrome b559 Preparations Isolated from Spinach Photosystem II Membrane Fragments

The capability of different manganese complexes to act as PS II electron donors in D1/D2/ cytochrome b 559 complexes has been analyzed by measuring actinic light-induced absorption changes at 680 nm (650 nm) and 340 nm, reflecting the photoaccumulation of Pheophytin- (Pheo-) and the reduction of NADP+ respectively. The data obtained reveal: a) the donor capacity of synthetic binuclear Mn(III)2 complexes containing aromatic ligands significantly exceeds that for MnCl2 in both cases, i.e. Pheo- photoaccumulation and NADP+ reduction; b) manganese complexes can serve as suitable electron donors for light-induced NADP+ reduction catalyzed by D1/D2/cytochrome b559 complexes and ferredoxin plus ferredoxin- NADP+ reductase under anaerobic conditions and c) the specific turnover rate of the system leading to NADP+ reduction is extremely small. The implications of these findings are briefly discussed

Dissolution influences on gypsum rock under short and long-term loading: Implications for dams

Dissolution of soluble substrates such as gypsum presents a major hazard to dams in many parts of the world. This research simulates hypothesised conditions beneath the Mosul Dam, northwest Iraq, where collapse of a karstic system associated with continuous fresh water supply from its reservoir is a recognised problem. Gypsum rocks from northern Iraq and similar rocks from Bantycock gypsum mine, UK, were analysed for short-term mechanical response following immersion (5 to 50 weeks) and long-term loading during immersion (maximum 50 weeks). New experimental devices were developed from a conventional oedometer. Cylinder samples provided a proxy for massive gypsum strata. Samples were permanently submerged at atmospheric water pressure, with groundwater recharge, flow and dissolution simulated by regular changes of water. Stress on each sample was progressively increased to a maximum of 2688 kPa. Small increases in strain were recorded by the end of each test but no failures occurred within 60 days. However, notable failure due to atmospheric water pressure and axial stress occurred over long time periods. Visible physical changes included a decrease in sample mass and volume. Similar change was recorded in ultrasonic velocities. These indicate that gypsum collapse risk beneath dams requires prolonged exposure to dissolution. The modified device performed well and was robust, and demonstrates that such a modification can provide a simple low cost system for conducting laboratory creep tests on weak rocks

Exploring the receptor origin of vibration-induced reflexes

STUDY DESIGN: An experimental design. OBJECTIVES: The aim of this study was to determine the latencies of vibration-induced reflexes in individuals with and without spinal cord injury (SCI), and to compare these latencies to identify differences in reflex circuitries. SETTING: A tertiary rehabilitation center in Istanbul. METHODS: Seventeen individuals with chronic SCI (SCI group) and 23 participants without SCI (Control group) were included in this study. Latency of tonic vibration reflex (TVR) and whole-body vibration-induced muscular reflex (WBV-IMR) of the left soleus muscle was tested for estimating the reflex origins. The local tendon vibration was applied at six different vibration frequencies (50, 85, 140, 185, 235, and 265 Hz), each lasting for 15 s with 3-s rest intervals. The WBV was applied at six different vibration frequencies (35, 37, 39, 41, 43, and 45 Hz), each lasting for 15 s with 3-s rest intervals. RESULTS: Mean (SD) TVR latency was 39.7 (5.3) ms in the SCI group and 35.9 (2.7) ms in the Control group with a mean (95% CI) difference of -3.8 (-6.7 to -0.9) ms. Mean (SD) WBV-IMR latency was 45.8 (7.4) ms in the SCI group and 43.3 (3.0) ms in the Control group with a mean (95% CI) difference of -2.5 (-6.5 to 1.4) ms. There were significant differences between TVR latency and WBV-IMR latency in both the groups (mean (95% CI) difference; -6.2 (-9.3 to -3.0) ms, p = 0.0001 for the SCI group and -7.4 (-9.3 to -5.6) ms, p = 0.011 for Control group). CONCLUSIONS: The results suggest that the receptor of origin of TVR and WBV-IMR may be different

"Sleep disparity" in the population: poor sleep quality is strongly associated with poverty and ethnicity

<p>Abstract</p> <p>Background</p> <p>Little is known about the social determinants of sleep attainment. This study examines the relationship of race/ethnicity, socio-economic status (SES) and other factors upon sleep quality.</p> <p>Methods</p> <p>A cross-sectional survey of 9,714 randomly selected subjects was used to explore sleep quality obtained by self-report, in relation to socioeconomic factors including poverty, employment status, and education level. The primary outcome was poor sleep quality. Data were collected by the Philadelphia Health Management Corporation.</p> <p>Results</p> <p>Significant differences were observed in the outcome for race/ethnicity (African-American and Latino versus White: unadjusted OR = 1.59, 95% CI 1.24-2.05 and OR = 1.65, 95% CI 1.37-1.98, respectively) and income (below poverty threshold, unadjusted OR = 2.84, 95%CI 2.41-3.35). In multivariable modeling, health indicators significantly influenced sleep quality most prominently in poor individuals. After adjusting for socioeconomic factors (education, employment) and health indicators, the association of income and poor sleep quality diminished, but still persisted in poor Whites while it was no longer significant in poor African-Americans (adjusted OR = 1.95, 95% CI 1.47-2.58 versus OR = 1.16, 95% CI 0.87-1.54, respectively). Post-college education (adjusted OR = 0.47, 95% CI 0.31-0.71) protected against poor sleep.</p> <p>Conclusions</p> <p>A "sleep disparity" exists in the study population: poor sleep quality is strongly associated with poverty and race. Factors such as employment, education and health status, amongst others, significantly mediated this effect only in poor subjects, suggesting a differential vulnerability to these factors in poor relative to non-poor individuals in the context of sleep quality. Consideration of this could help optimize targeted interventions in certain groups and subsequently reduce the adverse societal effects of poor sleep.</p

Biofeedback and progressive relaxation treatment of sleep-onset insomnia

Previous research suggests that self-defined insomniacs are distinguished from normals by high levels of anxiety and physiological arousal, which might be mitigated by muscle relaxation. This study assessed the relative effects of frontal EMG biofeedback, progressive relaxation, and a placebo set of “relaxation” exercises on the sleep of 18 onset insomniacs. Each subject was trained in one of these three methods for six half-hour sessions and slept in the laboratory for two consecutive nights before and after training. The experimental groups demonstrated significant decreases in physiological activity during training while changes in the control group were minimal. Reductions in sleep-onset time were: biofeedback group, 29.66 minutes; progressive relaxation group, 22.92 minutes; control group, 2.79 minutes. The experimental groups improved significantly ( p<.05 ) more than the control group, but did not differ from each other. No significant relationships between physiological levels and sleep-onset time were found, which suggests that muscle relaxation alone was not responsible for subjects' improvements. Since 20 minutes of daily practice were required to achieve an approximate 30-minute decrease in sleep-onset time, the practical utility of the methods is questioned.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44085/1/10484_2005_Article_BF01001167.pd

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

Change of physical and thermal decomposition properties of in situ heavy oil with steam temperature

Ikiztepe crude oil was subjected to four different steam temperatures during steam injection which was applied as an enhanced oil recovery process on a linear limestone model saturated with oil. Produced oils were characterized using density, viscosity measurements, pyrolysis experiments utilizing TGA and elemental analysis runs. Results showed that produced crude oils change in measured characteristics as compared to the original oil. These changes include an increase in H/C, and cracking activation energy, decrease in density, viscosity and amount of residue remaining after cracking (coke). Also, decrease in asphaltene amount, changes in the elemental composition of asphaltenes and increase in the cracking activation energies were observed at 225 degrees C run. These measurements show that the produced oils get lighter and differ compositionally from the original oil as steam temperature increases. Decrease in elemental sulphur amount is one of the major changes when environmental considerations are concerned. Residual oil left in the limestone pack on the other hand shows an increase in the low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO) activation energies as determined from TGA combustion experiments on the samples taken from the pack after steam injection experiments

Adsorption and gas transport in coal microstructure: investigation and evaluation by quantitative X-ray CT imaging

Natural gas (methane) production from coal seams is recognized as one of the valuable energy sources due to high storage capacity of coal to store gas at low pressures. It is known that coal composition, pore structure, and mineral matter properties affect both the amount of adsorbed quantity and kinetics of adsorption when the coals are considered for natural gas production or mediums for storing gas, mainly methane or carbon dioxide