Raman Spectroscopy of Oxygen Evolution Catalysts and PSII Manganese Model Compounds

Photosynthesis is the basis of life on earth, and oxygen evolution catalysts are key components of this complicated, yet not fully understood process. Photosystem II, a large membrane bound pigment-protein complex, is the key system that facilitates oxygenic photosynthesis via the oxygen evolving complex (a natural oxygen evolving catalyst). It is a key component in oxygen producing catalysts, which can be used in fields such as energy production and biomimetic catalysts. The oxygen evolution cycle, or Kok cycle going within it is still not studied completely. In this project, we were studying the vibrational (and structural) state of a Manganese model compound for PSII and functioning Ruthenium water oxidizing catalyst. The method for this experiment was Raman spectroscopy at two wavelengths in the visible region: 532nm and 442nm. The results obtained from our Manganese model compound are various Raman spectra which will be analyzed using DFT (Density Function theory) and can now be used to predict vibrations relevant to PSII while insights gained from functioning Ruthenium water oxidizing catalysts give clues to the chemistry of PSII

Inhibition of hypertrophy and improving chondrocyte differentiation by MMP-13 inhibitor small molecule encapsulated in alginate-chondroitin sulfate-platelet lysate hydrogel

Background: Mesenchymal stem cells are a promising cell source for chondrogenic differentiation and have been widely used in several preclinical and clinical studies. However, they are prone to an unwanted differentiation process towards hypertrophy that limits their therapeutic efficacy. Matrix metallopeptidase 13 (MMP-13) is a well-known factor regulated during this undesirable event. MMP-13 is a collagen degrading enzyme, which is also highly expressed in the hypertrophic zone of the growth plate and in OA cartilage. Accordingly, we investigated the effect of MMP-13 inhibition on MSC hypertrophy. Methods: In this study, 5-bromoindole-2-carboxylic acid (BICA) was used as an inhibitory agent for MMP-13 expression. After identifying its optimal concentration, BICA was mixed into a hydrogel and the release rate was studied. To prepare the ideal hydrogel, chondroitin sulfate (CS) and platelet lysate (PL) were mixed with sodium alginate (Alg) at concentrations selected based on synergistic mechanical and rheometric properties. Then, four hydrogels were prepared by combining alginate (1.5w/v) and/or CS (1w/v) and/or PL (20v/v). The chondrogenic potential and progression to hypertrophy of human bone marrow-derived mesenchymal stem cell (hBM-MSC)-loaded hydrogels were investigated under free swelling and mechanical loading conditions, in the presence and absence of BICA. Results: Viability of hBM-MSCs seeded in the four hydrogels was similar. qRT-PCR revealed that BICA could successfully inhibit MMP-13 expression, which led to an inhibition of Coll X and induction of Coll-II, in both free swelling and loading conditions. The GAG deposition was higher in the group combining BICA and mechanical stimulation. Conclusions: It is concluded that BICA inhibition of MMP-13 reduces MSC hypertrophy during chondrogenesis. Graphical abstract: Figure not available: see fulltext. © 2020 The Author(s)

Sexual behavior and awareness of Chinese university students in transition with implied risk of sexually transmitted diseases and HIV infection: A cross-sectional study

BACKGROUND: The vulnerability of young people to HIV and the recent emergence of the HIV epidemic in China have made it urgent to assess and update the HIV/STD risk profile of Chinese young people. METHODS: A self-administered questionnaire survey with cross-sectional design was conducted among 22,493 undergraduate students in two universities in Ningbo, China. Bivariate trend analysis and multiple logistic regression analysis were used to compare sexual behaviors and awareness between grades. RESULTS: Of respondents, 17.6% of males and 8.6% of females reported being sexually active. Condom was reported never/rarely used by 35% of sexually active students in both genders in the previous year. Pregnancy and induced abortion had each been experienced by about 10% of sexually active female students and the female partners of male students, and about 1.5% of sexually active students of both genders reported being diagnosed with an STD. Multivariate analysis revealed that students in lower grades, compared to those in higher grades, were more likely to have become sexually active before university, to have become aware of sex before high school, and to have been exposed to pornographic media before the age of 17 years, and for sexually active respondents of both genders, to have engaged in sex without using a condom. CONCLUSION: Sexual behaviors of Chinese university students are poorly protected and sexual behaviors and awareness may have been undergoing rapid change, becoming active earlier and more risky. If this trend continues, vulnerable sexual network will grow among them that allow more expansion of sexually transmitted diseases and HIV

Frequency and clinical patterns of stroke in Iran - Systematic and critical review

<p>Abstract</p> <p>Background</p> <p>Cerebrovascular disease is the second commonest cause of death, and over a third of stroke deaths occur in developing countries. To fulfil the current gap on data, this systematic review is focused on the frequency of stroke, risk factors, stroke types and mortality in Iran.</p> <p>Methods</p> <p>Thirteen relevant articles were identified by keyword searching of PubMed, Iranmedex, Iranian University index Libraries and the official national data on burden of diseases.</p> <p>Results</p> <p>The publication dates ranged from 1990 to 2008. The annual stroke incidence of various ages ranged from 23 to 103 per 100,000 population. This is comparable to the figures from Arab Countries, higher than sub-Saharan Africa, but lower than developed countries, India, the Caribbean, Latin America, and China. Similarly to other countries, ischaemic stroke was the commonest subtype. Likewise, the most common related risk factor is hypertension in adults, but cardiac causes in young stroke. The 28-day case fatality rate is reported at 19-31%.</p> <p>Conclusions</p> <p>Data on the epidemiology of stroke, its pattern and risk factors from Iran is scarce, but the available data highlights relatively low incidence of stroke. This may reflect a similarity towards the neighbouring nations, and a contrast with the West.</p

Using a modified Delphi methodology to gain consensus on the use of dressings in chronic wounds management

Objective: Managing chronic wounds is associated with a burden to patients, caregivers, health services and society and there is a lack of clarity regarding the role of dressings in improving outcomes. This study aimed to provide understanding on a range of topics, including: the definition of chronicity in wounds, the burden of illness, clinical outcomes of reducing healing time and the impact of early interventions on clinical and economic outcomes and the role of matrix metalloproteinases (MMPs) in wound healing. Method: A systematic review of the literature was carried out on the role of dressings in diabetic foot ulcer (DFU), and venous leg ulcer (VLU) management strategies, their effectiveness, associated resource use/cost, and quality of life (QoL) impact on patients. From this evidence-base statements were written regarding chronicity in wounds, burden of illness, healing time, and the role of MMPs, early interventions and dressings. A modified Delphi methodology involving two iterations of email questionnaires followed by a face-to-face meeting was used to validate the statements, in order to arrive at a consensus for each. Clinical experts were selected, representing nurses, surgeons, podiatrists, academics, and policy experts. Results: In the first round, 38/47 statements reached or exceeded the consensus threshold of 80% and none were rejected. According to the protocol, any statement not confirmed or rejected had to be modified using the comments from participants and resubmitted. In the second round, 5/9 remaining statements were confirmed and none rejected, leaving 4 to discuss at the meeting. All final statements were confirmed with at least 80% consensus. Conclusion: This modified Delphi panel sought to gain clarity from clinical experts surrounding the use of dressings in the management of chronic wounds. A full consensus statement was developed to help clinicians and policy makers improve the management of patients with these conditions

Crystallization Behavior of Poly(l-lactide) Films in Presence of Mg(OH)2 and l-Lactide

The effects of magnesium hydroxide and l-lactide dimer as additives on thermal properties and morphology of poly(l-lactide) (PLLA) films were studied. Hence, neat PLLA films and films containing additives (10% w/w) were prepared in dichloromethane at room temperature via solution casting. To evaluate thermal history on polymer properties, PLLA films were annealed by different processes. In one process, designated as A, PLLA films were heated from 20 up 140oC, then held for 1 h and cooled to room temperature. In another process, designated as B, melted PLLA sampleswhich had been maintained at 200oC for 5 min were cooled with a rate of -20oC/min to 140oC and annealed for 1 h before being cooled to room temperature. In the next process designated as C, the melted PLLA samples after5 min of staying at 200oC were being quenched to 0oC. Then the samples were heated to 140oC followed by annealing for 1 h before being cooled to room temperature. The crystallization and morphology properties of PLLAfilms were studied using polarized optical microscopy and differential scanning calorimetry. It is found that the percentage of crystal and spherulitic formation inside PLLA films were influenced by thermal history and presenceof the additives. The type of additives did not affect melting point (Tm) of the films annealed through different processes of A to C, while they had influence on Tm of the films, significantly. It is to be noted that some spheruliteswere formed in films during B process. During C process, however, the nucleation rate increased due to quenching which enhanced the spherulites formation

Identification of Plant-parasitic Nematodes in Cotton Fields in Southern Khorasan Province

Introduction: Gossypium species are distributed in the arid to semiarid regions of the tropical and subtropical, generally shrubs or shrub-like plants. The leaves are broad and lobed with three to five lobes. The seeds are contained in a capsule called a "boll", each seed surrounded by fibers. Commercial species of cotton plant are Gossypium hirsutum (>90% of world production), G. barbadense (3-4%), G. arboreum and G. herbaceum (together, 2%). Cotton is grown as a cash crop; it is often grown in a monoculture system that favors the development of a nematode community dominated by one or a few parasitic species. The different genera of plant parasitic nematodes such as Haplolaimus, Helicotylenchus, Blanolaimus, Pratylenchus, Paratrichodorus, Meloidogyne, Merlinius, Xiphinema, Tylenchorynchus, Rotylenchulus, Scutellonema, Heterodera, Ditylenchus, Longidorus, Aphelenchoides, Aphelenchus were recorded from cotton fields in the world. The objective of this study was to investigate the plant parasitic nematodes associated with cotton fields in Southern Khorasan province of Iran. Materials and Methods: In order to identify the plant parasitic nematodes in cotton fields in Southern Khorasan province, 56 soil samples were collected from different areas during 2013 and 2014. Soil samples were washed and nematodes were extracted by combined sieving and centrifugal-flotation method of Jenkins (1964) and Whitehead tray method (1965). Nematodes were fixed and transferred to glycerin by using the method of De Grisse (1969). The permanent slides were prepared and the nematodes were studied by light microscope. Results and Discussion: In this study, 15 species from 10 genera related to order Tylenchomorpha, were identified as follows: Aphelenchus avenae, Basiria graminophila, Boleodorus clavicaudatus, B. pakistanensis, B. thylactus, Ditylenchus hexaglyphus, D. tenuidens, D. valveus, Geocenamus rugosus, Filenchus vulgaris, Pratylenchus neglectus, P. thornei, Scutylenchus quadrifer, Merlinius brevidens, Zygotylenchus guevarai. One genus of cotton-parasitic nematodes known to cause yield loss were found in this survey (Pratylenchus spp). Other parasitic nematodes not known to cause yield loss also were found. Three species, including Boleodorus pakistanensis, Ditylenchus hexaglyphus, D. valveus are reported as new records for Iran. Boleodorus pakistanensis is characterized by four incisures, head low, unstriated and conoid shape, stylet 8.5-10µm with cone short and slender knobs, non-muscular median bulb, Basal bulb pyriform, posterior vulva (v=68.1-72.4 ; v/=77.5-88.4). Tail elongate-conoid, central arcuate, ending in a finely rounded terminus. B. pakistanensis resembles, B. flexuosus B. teres, B. thylactus and B. cylindricus. B. thylactus but can be differentiated by the more posterior position of the opening of the dorsal gland (2 vs 3-5); B. flexuosus has a more anterior vulva (V=54-63 vs 68.1-72.4); B. teres has a more anterior vulva (V=54-63 vs 68.1-72.4), tail shape and stylet length (10-12 vs 8.5-10); B. cylindricus has a more anterior position of the opening of the dorsal gland (7 vs 3-5) and more tail (88-101 vs 72-88.5). Ditylenchus hexaglyphus is characterized by six lines in lateral fields, low head, stylet 8-9µm with cone shorter than the shaft and small elongated knobs, non-muscular median bulb, Posterior bulb offset, posterior vulva (v=82.3 -83.5; v/=87.8-89.6). Tail ventrally curved, terminus rounded. Having non-muscular median bulb, six incisures, short stylet and posterior vulva. D. hexaglyphus resembles D .medians, D. taylori, D. affinis, and D. tuberosus. However, none of these species have such small stylet knobs, and all but D. affinis have longer PUS than that observed in D. hexaglyphus. D. taylori more anterior vulva (V=75-77 vs 82.3-83.5) and tail appears to be thinner (c/=6-7 vs 2.9-3.8); D. affinis has a more anterior vulva (V=76-80 vs 82.3-83.5). Ditylenchus valveus is characterized by six incisures, annulated head, stylet 8-9µm with short cone and small rounded knobs, muscular median bulb with small. Posterior bulb offset, posterior vulva (v=74.3 -81.5; v/=84.9-89.2). Tail terminus rounded. Because of six incisures, short stylet, vulva position, oesophagus structure and tail shape, D. valveus resembles D. acutatus D. myceliophagus and D. medicaginis. D. myceliophagus differs from D.valveus by tail shape and generally overlapping oesophagus; D. medicaginis differs from D. valveus mainly by tail shape and also slightly more posterior vulva position (78-83 vs 74.3-81.5); D. acutatus differs from D. valveus mainly by tail shape. Conclusion: In this study, 15 species from 10 genera of plant parasitic nematodes were identified. Among these genera and species, three species including Boleodorus pakistanensis, Ditylenchus hexaglyphus, D. valveus are reported as new records for Iran