The effect of host structure on the selectivity and mechanism of supramolecular catalysis of Prins cyclizations.

The effect of host structure on the selectivity and mechanism of intramolecular Prins reactions is evaluated using K12Ga4L6 tetrahedral catalysts. The host structure was varied by modifying the structure of the chelating moieties and the size of the aromatic spacers. While variation in chelator substituents was generally observed to affect changes in rate but not selectivity, changing the host spacer afforded differences in efficiency and product diastereoselectivity. An extremely high number of turnovers (up to 840) was observed. Maximum rate accelerations were measured to be on the order of 105, which numbers among the largest magnitudes of transition state stabilization measured with a synthetic host-catalyst. Host/guest size effects were observed to play an important role in host-mediated enantioselectivity

Sanction or financial crisis? An artificial neural network-based approach to model the impact of oil price volatility on stock and industry indices - Under review

In this paper, we model the impact of oil price volatility on Tehran stock and industry indices in two periods of international sanctions and post-sanction. To analyse the purpose of study, we use Feed-forward neural net-works. The period of study is from 2008 to 2018 that is split in two periods during international energy sanction and post-sanction. The results show that Feed-forward neural networks perform well in predicting stock market and industry, which means oil price volatility has a significant impact on stock and industry market indices. During post-sanction and global financial crisis, the model performs better in predicting industry index. Additionally, oil price-stock market index prediction performs better in the period of international sanctions. Herein, these results are, up to some extent, important for financial market analysts and policy makers to understand which factors and when influence the financial market, especially in an oil-dependent country such asIran with uncertainty in the international politics.Keywords: Feed-forward neural networks·Industry index·International energy sanction·Oil price volatility·Tehran stock inde

Effects of enrichment of Artemia urmiana with LC-PUFA on survival and resistance to pH stress in larvae of Angel fish (Peterophylum scalar)

The effects of using n-3 LC-PUFA -enriched Artemia nauplii and newly hatched Artemia on survival and resistance to pH stress in larvae of angel fish (Peterophylum scalar) were examined In tow 20 days period. In the first step of the experiment the larvae with an average weight of 0.86 ±0.03mg were fed with tow diets (enriched Artemia nauplii and newly hatched Artemia) for 20 days. At the end of the first step of the experiment, the significantly (p<0.05) higher survival rate was observed in larvae fed with enriched Artemia (90.66%) than the larvae fed with newly hatched Artemia (83.66%). In the second step of the experiment the larvae with an average weight of 20. 03 ±3.73mg were fed only with commercial diet for 20 days. At the end of the second 20th days of the experiment, larvae exposed at pH stress (including 5.5, 6.5, 8.8 and 9.5) for 96 hours. The Result showed that the larvae were fed with n-3 LC-PUFA-enriched Artemia have a higher significant survival rate than other group in the period of the experiment and pH stress (p<0.05). Therefore, using of n-3 LC-PUFA-enriched Artemia recommended for increasing survival rate and the resistance to pH stress

Iranian agriculture advisors’ perception and intention toward biofuel: green way toward energy security, rural development and climate change mitigation

Agricultural professionals play an important role in informing and educating farmers about biofuel through teaching or extension work. One of the questions commonly asked is if they are knowledgeable and possess positive attitude towards renewable energy sources. The aim of this article is to investigate Agricultural professionals’ attitude and willingness towards biofuel using a random sample of professionals (n =180) in a survey conducted in Zanjan province in Iran. Structural equation modeling showed that “Outcome efficacy”, “problem perception” and “perceived benefits” can significantly predict just about 38% variance of Agricultural professionals’ personal norm. In turn, personal norm can predict 35% variance of Agricultural professionals’ willingness. The findings yield public policy recommendations for stimulating biofuel extension and deployment among Agricultural professionals

The frequency of shiga toxin producing Escherichia coli in patients with urinary tract infection in Iran: Systematic review and meta-analysis

Background and Objectives: Escherichia coli is the main cause of urinary tract infection regardless of age. If it harbors shiga toxin, hemolytic uremic syndrome may occur. The aim of this study was to determine the incidence and prevalence of Shiga Toxin producing E. coli (STEC), as a cause of urinary tract infection in Iran. Methods: Major medical search engines, Iranian scientific search engines, and Iranian databases for thesis were searched for relevant English or Persian keywords for urinary tract infection, shiga-toxin Escherichia coli, and hemolytic uremic syndrome in Iran, which were published between 1985 and 2017. The study was followed by the PRISMA statement. Point prevalence and proportion were calculated by random effect and I2 for heterogeneity and expressed as 95 confidence intervals. MedCalc version 15 and SPSS IBM were used for statistical analysis. Results: A total of six articleswith 1,111 positive E. coli urine cultures met all the inclusion criteria and were eligible for the final analysis. All studies had a cross-sectional design. The qualities of two studies were poor with low to moderate risk of bias. Considering 32 samples reported as positive for STEC, the pooled prevalence for E. coli associated UTI was 3.46 (95 CI, 0.89 to 7.65, I2 = 86). The study was heterogeneous for publication bias. Conclusions: This review indicated that STEC constituted some percentage of uropathogenic E. coli that required to be considered during culture processing and longer clinical follow up of the patients for the occurrence of STEC-related morbidity. © 2018, Author(s)

On the mechanism of ubiquinone mediated photocurrent generation by a reaction center based photocathode

Upon photoexcitation, the reaction center (RC) pigment-proteins that facilitate natural photosynthesis achieve a metastable separation of electrical charge among the embedded cofactors. Because of the high quantum efficiency of this process, there is a growing interest in their incorporation into biohybrid materials for solar energy conversion, bioelectronics and biosensing. Multiple bioelectrochemical studies have shown that reaction centers from various photosynthetic organisms can be interfaced with diverse electrode materials for the generation of photocurrents, but many mechanistic aspects of native protein functionality in a non-native environment is unknown. In vivo, RC's catalyse ubiquinone-10 reduction, protonation and exchange with other lipid phase ubiquinone-10s via protein-controlled spatial orientation and protein rearrangement. In contrast, the mechanism of ubiquinone-0 reduction, used to facilitate fast RC turnover in an aqueous photoelectrochemical cell (PEC), may not proceed via the same pathway as the native cofactor. In this report we show truncation of the native isoprene tail results in larger RC turnover rates in a PEC despite the removal of the tail's purported role of ubiquinone headgroup orientation and binding. Through the use of reaction centers with single or double mutations, we also show the extent to which two-electron/two-proton ubiquinone chemistry that operates in vivo also underpins the ubiquinone-0 reduction by surface-adsorbed RCs in a PEC. This reveals that only the ubiquinone headgroup is critical to the fast turnover of the RC in a PEC and provides insight into design principles for the development of new biophotovoltaic cells and biosensors

Potential drugs used in the antibody–drug conjugate (ADC) architecture for cancer therapy

Cytotoxic small-molecule drugs have a major influence on the fate of antibody–drug conjugates (ADCs). An ideal cytotoxic agent should be highly potent, remain stable while linked to ADCs, kill the targeted tumor cell upon internalization and release from the ADCs, and maintain its activity in multidrug-resistant tumor cells. Lessons learned from successful and failed experiences in ADC development resulted in remarkable progress in the discovery and development of novel highly potent small molecules. A better understanding of such small-molecule drugs is important for development of effective ADCs. The present review discusses requirements making a payload appropriate for antitumor ADCs and focuses on the main characteristics of commonly-used cytotoxic payloads that showed acceptable results in clinical trials. In addition, the present study represents emerging trends and recent advances of payloads used in ADCs currently under clinical trials. © 2019 Wiley Periodicals, Inc

Angiotensin-converting enzyme inhibitor, Enalapril, inhibits tumor growth and potentiates the antitumor efficacy of 5-FU in colorectal cancer

OBJECTIVE: Colorectal cancer (CRC) is among the leading causes of cancer-related death, indicating the need for the identification of novel therapeutic approaches to increase the activity of current therapy or have better efficacy. Angiotensin-converting enzyme (ACE) is being reported to be associated with aggressive behaviors of CRC cells and poor prognosis. Here we explored the therapeutic potency of targeting ACE by Enalapril in CRC in vivo model. MATERIALS AND METHODS: A xenograft model of CRC was used to investigate the effects of Enalapril alone, or in combination with 5-FU, on tumor growth following histological staining (Hematoxylin and Eosin and Masson trichrome staining) and biochemical studies of Malondialdehyde (MDA), total thiols, superoxide dismutase (SOD) and catalase (CAT) activities. RESULTS: Enalapril reduced tumor growth and increased tumor necrosis; this effect was more pronounced in Enalapril plus 5-FU combination. Enalapril/5-FU was able to decrease tumor fibrosis and collagen content. ACE inhibitors also increased MDA level, as an oxidative stress marker, while reducing total thiol group levels, SOD and CAT enzyme activity. CONCLUSIONS: Our findings provide a novel insight on the therapeutic potential targeting of the renin–angiotensin system as a new therapeutic option in combination with current therapeutic agents 5-FU in the treatment of CRC

Impact damage characteristics of carbon fibre metal laminates : experiments and simulation

In this work, the impact response of carbon fibre metal laminates (FMLs) was experimentally and numerically studied with an improved design of the fibre composite lay-up for optimal mechanical properties and damage resistance. Two different stacking sequences (Carall 3–3/2–0.5 and Carall 5–3/2–0.5) were designed and characterised. Damage at relatively low energy impact energies (≤30 J) was investigated using Ultrasonic C-scanning and X–ray Computed Tomography (X-RCT). A 3D finite element model was developed to simulate the impact induced damage in both metal and composite layers using Abaqus/Explicit. Cohesive zone elements were introduced to capture delamination occurring between carbon fibre/epoxy plies and debonding at the interfaces between aluminium and the composite layers. Carall 5–3/2–0.5 was found to absorb more energy elastically, which indicates better resistance to damage. A good agreement is obtained between the numerically predicted results and experimental measurements in terms of force and absorbed energy during impact where the damage modes such as delamination was well simulated when compared to non-destructive techniques (NDT)

Experimental Investigation and Large-Eddy Simulation of the Turbulent Flow past a Smooth and Rigid Hemisphere

Computations carried out on the German Federal Top-Level Computer SuperMUC at LRZ Munich under the contract number pr84na.International audienceThe objective of the present paper is to provide a detailed experimental and numerical investigation on the turbulent flow past a hemispherical obstacle (diameter D). For this purpose, the bluff body is exposed to a thick turbulent boundary layer of the thickness δ = D/2 at Re = 50,000. In the experiment this boundary layer thickness is achieved by specific fences placed in the upstream region of the wind tunnel. A detailed measurement of the upstream flow conditions by laser-Doppler and hot-film probes allows to mimic the inflow conditions for the complementary large-eddy simulation of the flow field using a synthetic turbulence inflow generator. These clearly defined boundary and operating conditions are the prerequisites for a combined experimental and numerical investigation of the flow field relying on the laser-Doppler anemometry and a finite-volume Navier-Stokes solver for block-structured curvilinear grids. The results comprise an analysis on the unsteady flow features observed in the vicinity of the hemisphere as well as a detailed discussion of the time-averaged flow field. The latter includes the mean velocity field as well as the Reynolds stresses. Owing to the proper description of the oncoming flow and supplementary numerical studies guaranteeing the choice of an appropriate grid and subgrid-scale model, the results of the measurements and the prediction are found to be in close agreement