There has been a tremendous surge in research on the synthesis of various metal compounds aimed at simulating the water-oxidizing complex (WOC) of photosystem II (PSII). This is crucial because the water oxidation half reaction is overwhelmingly rate-limiting and needs high over-voltage (approx. 1 V), which results in low conversion efficiencies when working at current densities required for hydrogen production via water splitting. Particular attention has been given to the manganese compounds not only because manganese has been used by nature to oxidize water but also because manganese is cheap and environmentally friendly. The manganese-calcium cluster in PSII has a dimension of about approximately 0.5 nm. Thus, nano-sized manganese compounds might be good structural and functional models for the cluster. As in the nanometre-size of the synthetic models, most of the active sites are at the surface, these compounds could be more efficient catalysts than micrometre (or bigger) particles. In this paper, we focus on nano-sized manganese oxides as functional and structural models of the WOC of PSII for hydrogen production via water splitting and review nano-sized manganese oxides used in water oxidation by some research groups.

Nano-sized particles of manganese oxides have been prepared by a very simple and cheap process using a decomposing aqueous solution of manganese nitrate at 100 °C. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction spectrometry have been used to characterize the phase and the morphology of the manganese oxide. The nano-sized manganese oxide shows efficient catalytic activity toward water oxidation and the epoxidation of olefins in the presence of cerium(IV) ammonium nitrate and hydrogen peroxide, respectively.

In this report, gold or silver deposited on layered manganese oxide has been synthesized by a simple method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, atomic absorption spectroscopy, and energy-dispersive X-ray mapping. The gold deposited on layered manganese oxide showed efficient catalytic activity toward water oxidation in the presence of cerium(IV) ammonium nitrate. The properties associated with this compound suggest it is a functional model for the water-oxidizing complex in photosystem II.

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Background Robust optimization (RO) has been proposed to mitigate breathing motion uncertainty during treatment in intensity‐modulated radiation therapy (IMRT) planning for breast or lung cancer. RO is a pessimistic approach that implicitly trades off average‐case for worst‐case treatment plan quality. Pareto robust optimization (PRO) provides a mechanism for improving nonworst‐case plan outcomes, but often remains overly conservative in the average case. Purpose The goal of this study is to characterize the trade‐off between the optimality of robust IMRT plans in the worst case and the treatment quality in nonworst‐case realizations of breathing motion. We provide a light Pareto robust optimization (LPRO) method for IMRT and test its clinical viability for improving the average‐case plan quality while preserving robustness, in comparison to RO and PRO plans. Methods Five clinical left‐sided breast cancer patients were included in the study, each with an associated 4D‐CT dataset approximating their breathing cycle. Using simulation, 50 different breathing patterns were generated for each patient. A first‐stage optimization was solved with the objective of cardiac sparing while ensuring robustness on the target dose under breathing uncertainty. Next, a second‐stage objective of overdose minimization was considered to improve plan quality in a controlled LPRO framework. For the simulated breathing scenarios, the trade‐off between loss of average cardiac sparing at worst‐case and the overdose to the breast was quantified by calculating the accumulated dose for each plan in each breathing scenario. Finally, the RO, PRO, and LPRO plans were each evaluated using eight clinical dose–volume criteria on the target and organs at risk. Results The LPRO models allowed for significantly sharper dose falloffs in the expected dose instances, relative to both RO and PRO models. Plans began looking valid for delivery with average allowances of as little as +0.1 Gy additional dose to the heart, and most patients experienced diminishing returns beyond +0.2 Gy. Conclusions Without sacrificing robustness, the LPRO approach produces viable plans with true total‐target irradiation. Furthermore, the plans produced were able to reduce the nonworst‐case downside typical of RO, without the characteristic overdosing or average‐case pessimism seen in prior models.

Background & Objective: ubstance abuse is one of the major biological, psychological, and social issues. Various factors contribute to the explanation of addiction. One of these factors is resiliency that causes constructive coping with stressful problems. Also, The quality of life that means the individual's sense of satisfaction from different areas of life and Subjective well-being that includes positive emotional experiences are involved in explaining high-risk behaviors such as substance abuse. So considering that drug addiction is one of the psychosocial and social harms associated with many negative consequences, it is necessary to study the factors that are involved in Substance abuse. Thus this research aimed to determine the Comparison of resilience, quality of life, and subjective well-being in Men with opiate substance abuse and normal men of Rasht city. Methods: In the current research, two groups compared, and the research method was casual-comparative. The statistical population included all opium dependent men referring to addiction treatment centers in Rasht city. In this research, 200 men (100 males with drug abuse and 100 normal males) selected with available sampling method, then Groups were matched in terms of demographic characteristics. Participants responded to psychological resilience scale, world health organization quality of life questionnaire, and subjective wellbeing scale. The research tools were valid and reliable. The Data analyzed by SPSS-21 software using multivariable analysis of variance. Results: The mean age of the addict group was 28.90 years, with a standard deviation of 3.34. Also, the mean age of the healthy group was 29.79 years, with a standard deviation of 3.91. The majority of the addict group (66%) and healthy group (64%) had a high school diploma. The mean scores of the addict group in resilience, quality of life, and subjective well-being were 48.36, 71.57, and 258.18 and the mean scores of the normal group in resilience, quality of life and subjective well-being were 64.32, 75.37, and 304.8. The results of the multivariable analysis of variance showed that there is a significant difference between groups In terms of resiliency and the scores of Men with opiate substance abuse were lower than normal men (F= 116.49; p<0.001). Also, the results of the multivariable analysis of variance showed that there is a significant difference between groups In terms of quality of life and the scores of Men with opiate substance abuse were lower than normal men (F=40.12; p<0.001). Finally, the results of the multivariable analysis of variance showed that there is a significant difference between groups In terms of subjective well-being and the scores of Men with opiate substance abuse were lower than normal men (F= 50.99; p<0.001). Conclusion: Low level of resilience, quality of life, and well-being are factors that lead individuals toward more drug abuse. Psychological resilience makes individuals more flexible for life-threatening events. The quality of life increases an indiv...

Proto-neutron stars are born when a highly evolved and massive star collapses under gravity. In this paper, we investigate the spontaneous scalarization in proto-neutron stars. Based on the scalar tensor theory of gravity as well as the physical conditions in proto-neutron star, we examine the structure of proto-neutron star. To describe the fluid in proto-neutron star, we utilize SU(2) chiral sigma model and the finite temperature extension of the Brueckner–Bethe–Goldstone quantum many-body theory in the Brueckner–Hartree–Fock approximation. Here, we apply the equation of state of proto-neutron stars considering different cases i.e. hot pure neutron matter and hot $$\beta $$ β -stable neutron star matter without neutrino trapping as well as with neutrino trapping. The effects of temperature and entropy of proto-neutron stars on the star structure are also studied. Our results confirm that the spontaneous scalarization is affected by different physical conditions in proto-neutron stars.