Homogeneous and Heterogeneous Cluster-Based Catalysts for Asymmetric Reactions

Synthesis and characterization of new transition metal carbonyl clusters has been undertaken, and evaluation of the new clusters to act as catalysts/catalysts precursor in asymmetric reactions has been carried out. The catalytic hydrogenation of tiglic acid under relatively mild conditions, using diastereomeric clusters of the general formula [(µ-H)2Ru3(µ3-S)(CO)7(µ-1,2-L)] (L= chiral diphosphine of the ferrocene-based Walphos and Josiphos families) as catalysts, reveal different catalytic behavior in terms of conversion and enantioselectivity. The observed reversal in enantioselectivity when the chirality of the cluster framework is changed strongly supports catalysis by intact Ru3 clusters. A proposed catalytic cycle generated by CO loss from the parent catalyst has been investigated. The ability of carbonyl clusters based on rhenium, ruthenium and osmium derivatised with chiral phosphines and phosphiranes to catalyse the asymmetric hydrogenation of tiglic acid shows high to excellent conversion rates with low to moderate enantioselectivity. A high conversion rate (up to 99%) and an enantioselectivity of 19% have been achieved with the cluster [(µ-H)4Ru4(CO)11(ArPH2)] {where ArP = (R)-(2'-methoxy-[1,1'-binaphthalen]-2-ylphosphine)} acting as catalyst/catalyst precursor; this is, to the best of our knowledge, the first example of an asymmetric hydrogenation induced by a chiral primary phosphine. A chiral solid catalyst derived from the immobilization of [H4Ru4(CO)10(µ-1,2-W001)] (W001 = chiral diphosphine ligand of the Walphos family) onto functionalized MCM-41 has been shown to exhibit excellent conversion rates (> 99%) and as high enantiomeric excesses (≈ 80%) as that of its homogeneous counterpart. The good catalytic properties are coupled with good recyclability of the mesoporous catalyst

Should hysteroscopy be combined with laparoscopy in endometriosis associated infertility?

AbstractObjectivesThe aim of this study was to evaluate the uterine cavity in cases of endometriosis associated infertility using office hysteroscopy.Study designA retrospective observational analytical study.Patients and methodsThe study conducted on 50 women with endometriosis diagnosed by laparoscopy seeking fertility treatment between December 2013 and October 2015. The study was approved from Ethical committee board of the faculty of Medicine Alexandria University. After explanation of the study objectives and procedures to all eligible women, informed written consent was signed. Thorough history taking, clinical examination and vaginal ultrasound examination was conducted to all participants. Office Hysteroscopy was done in the early proliferative phase using normal saline as a distention medium. All data were pulled from the reports at Elshatby Maternity University Hospital.ResultsThe age of the study group was ranging from 20 to 34 years with the mean of 29 years±3 years. 42 cases were primary infertility counting for 84% of patients and 8 cases were secondary infertility counting for 16% of patients. This reflects the strong impact of endometriosis on fertility. Normal uterine cavity was diagnosed in 35 cases representing 70% of the studied patients group. 10 cases had endometrial polyps representing 20% of the studied patients group. 5 cases had a uterine septum representing 10% of the studied patients group. 2 cases had a hypo plastic uterus in addition to uterine septum representing 4% of the studied patients group. Normal uterine cavity were diagnosed using hysteroscopy in 63.0% (18/23) in women having ovarian endometrioma while this normality was 78.3% (17/27) in women without endometrioma however, The prevalence of endometrial polyp was 25.9% in cases with endometrioma and 13% in cases without endometrioma. Cases with a uterine septum were 7.4% (2/23) of cases having ovarian endometrioma and 13.0% (3/27) of cases without it. Two cases with endometrioma out of 23 cases were diagnosed to have hypoplastic uterus. No uterine abnormalities were found in stage 1 endometriosis in contrast to the presence of 53.2% of patients with a uterine abnormality in stage 2. Also stage 3 patients were all having a normal uterine cavity while only 72.4% of patients with stage 4.ConclusionFrom the results of this study we can conclude that there is a High prevalence of endometrial polyps in cases of endometriosis. Also there is a High prevalence of uterine anomalies in cases of endometriosis. Still, we neither cannot recommend hysteroscopy as a routine in any endometriosis patient undergoing laparoscopy

Engineering characteristics of rocks in Qatar; Applications on excavation and tunneling

Excavation as well as tunneling have become fundamental operations in the advanced civil engineering field. In Qatar, many subsurface construction operations take place in rocks. However, the lack of studies and research that analyze the subsurface rock components from a geotechnical engineering perspective has created unexpected construction conditions. Most of similar studies handled concerns about properties related to oil and gas fields. This research aims to provide a geotechnical study for rocks in Qatar, and to illustrate the impact of the existence of these rock layers on two civil applications; namely excavation and tunneling. During this study, soil investigation reports and rock samples are collected from several bores located in Qatar, and a classification system is utilized to classify the rock samples to identify and study the properties of the existed rocks. Also, numerous production rates from different tunneling and excavation projects are recorded and analyzed, in order to clarify the relation between these rates and the classified rock layers. Based on this analysis, a geotechnical study and mapping system for the rocks in Qatar are presented. Reliable tools for predicting the average productivities of excavation and tunneling projects in Qatar are developed, these tools are aiming to facilitate designing, bidding and executing processes involved with these types of rocks

Ontogeny of rat CYP2E1 and CYP1A2 : a characterization and a pharmacokinetic model

Infantile exposure to xenobiotics, e.g. from breastfeeding, poses a serious toxicity risk. Since the toxicokinetic mechanisms that principally determine exposure outcomes undergo a significant developmental maturation, infants may respond to exposures in a different way than adults. Hence, suitable model systems are required to provide risk relevant information in pediatric populations. This dissertation’s primary goal was to provide a critical evaluation of two such model systems; first, a pharmacokinetic model that may predict an infant’s capacity to eliminate toxicants by cytochrome P-450 (CYP) mechanisms and second, the developing rat as a model of human CYP2E1 and CYP1A2 ontogeny.The first objective was to evaluate underlying assumptions of a pharmacokinetic model that describes the ontogeny of hepatic CYP activity using the rat. The study recognized some discrepancies with the stated assumptions. The impact of these discrepancies on the potential applicability of the model is discussed. As proof-of-concept, the observed data were fit to a model describing rat CYP2E1 and CYP1A2 ontogeny. A reasonable correlation (r = 0.75) was observed between observed and predicted oral clearance values of a CYP2E1 substrate indicating the potential applicability of such a model in risk assessment. The second objective was to conduct an extensive characterization of rat hepatic CYP2E1 and CYP1A2 ontogeny at mRNA, protein, activity and intrahepatic expression levels. The results were compared to available human data to determine the appropriateness of the rat for assessment of toxicokinetic mechanisms underlying age-dependent differences in susceptibility to toxicity. Similarities in age-dependent changes in mRNA, activity and zonal hepatic expression patterns were noted between the rat and human prior to weaning. Unlike human data, rats show good correlation between changes in CYP2E1 and CYP1A2 activity and transcript levels, but not with the immunoquantifiable protein. Recognizing such similarities and differences between rats and human regarding onset, rate and pattern of CYP ontogeny will improve the accuracy of rat-to-human extrapolation of developmental toxicokinetic data. Overall, the dissertation research provides mounting and supportive evidence for the use of such model systems in providing risk-relevant information in pediatric populations and to identify toxicokinetic mechanisms underlying age-dependent differences in susceptibility to toxicity

Functional analysis of non-viral miRNA replacement therapy in colon carcinoma in vitro and in vivo

MicroRNAs (miRNAs) are small RNA molecules with perfect or imperfect homology to their target mRNA. They have been shown to specifically interfere with the expression of their target protein(s). Moreover, microRNAs play an important role in the pathogenesis of cancer, where some microRNAs act as tumor suppressors by targeting lethal oncogenes, and others act as oncogenes by targeting suppressor genes. Thus, microRNAs can be involved directly or indirectly in important cellular processes such as proliferation, differentiation and apoptosis. Understanding the functions and importance of microRNAs could lead to the discovery of new strategies for controlling of cancer. This thesis was aiming at the possibility of using non-viral delivery systems for microRNAs into mammalian cell lines, and examined their efficacies. To this end, three different transfection reagents, linear Jet-PEI, branched PEI F25-LMW and INTERFERin, were used in vitro, either commercially available or prepared in our lab. The work was concentrating on colon cancer as a tumor model, and two representative cell lines, LS174t and HCT-116, were selected as a platform to conduct the experiments. The studies focused on miR-143 and miR-145, which had been implicated previously with cancer development and progression. It was found in miRNA transfection experiments that miR-143 and miR-145, which are downregulated in colon cancer, have the ability to inhibit the progression of the cancer through different regulatory mechanisms, proliferation and apoptosis. Some important genes, which play important roles in tumorigenesis and tumor progression, were found to be negatively regulated by both miR-143 and miR-145. More specifically, ERK5 (Mitogen Activated Protein Kinase) which plays an essential role in the proliferation of colon cancer was suppressed by miR-143 and miR-145. Likewise, c-Myc was negatively regulated by miR-145, but these results were only at the protein level, i.e., no significant effects were determined on c-Myc transcription. Furthermore, it was found that the^inhibitory effects were depending on several factors such as cell line, transfection reagent, time of incubation and concentration of miRNA complex. Thus, the cellular delivery of microRNAs miR-143 and miR-145 showed profound inhibitory effects on the proliferation and soft agar colony formation of LS174t and HCT- 116 cells, and induced apoptosis in LS174t cells. Moreover, miR-145 was examined for its tumor inhibitory effect in vivo. To this end, athymic nude mice bearing s.c. colon carcinoma xenografts were treated with PEIcomplexed miR-145 by systemic or local injection. Profound anti-tumor effects upon PEImediated miR-145 delivery were found which were again dependent on the downregulation of specific target genes. Taken together, microRNA replacement therapy may represent a promising approach in tumor treatment, and this thesis establishes the PEI-mediated therapeutic delivery of miR- 145 in colon carcinoma

Bread subsidy policies in Egypt: A SWOT analysis of recent systemic reforms

Food subsidy programs are a key component of Egypt’s social policy. Recently, the Egyptian government introduced a number of reforms to address the targeting and quality of subsidized bread. These policies focused on addressing loss of subsidized flour through the different supply chain processes, compromised quality and the need for the rationalization of consumption. This thesis provides an analysis of these new reforms. The study relies on qualitative research methods through structured and semi-structured in-depth interviews with several ranks in the supply chain including those in the Ministry of Supply and Internal Trade as well as various consumers of subsidized food products. The study applied the strengths, weaknesses, opportunities and threats (SWOT) analysis on the newly applied systemic reforms. Findings demonstrate that the new system improved and resolved most of the previous system’s problems; however, the new system has some weaknesses that should be dealt with rapidly. Most of these problems are pertaining to administrative and procedural issues. Thus, a set of recommendations have been suggested in order to deal with the current weaknesses of the new system

Fatigue loading characteristic for the composite steel-concrete beams

During the past few decades, composite beams (steel I beam and concrete slab) have had a wide range of uses, particularly in bridge construction. This is due to its relatively low economic cost compared to individual steel structures or reinforced concrete structures. This type of bridges in particular and many similar industrial structures in general are repeatedly subjected to fatigue loads, and that is frequently, as a result of the vehicles passing on these bridges or the vibrations caused by the machines in the industrial facilities. It has been observed during the successive studies that they have been interested in studying this problem that it is concerned with the external structural behavior of these beams  such as a load –deflection relation, observing the cracks appearing during the failure stage and the strain in the steel and concrete flanges. Hence, in this study we have focused on several factors affecting mode of failure of these beams under the fatigue loads, and the common element in all stages of failure was the shear stud, specifically the welding collar at the base of this stud as it is a structurally weak region

Attenuated Combined Action of Cyclosporine A and Hyperlipidemia on Atherogenesis in Rabbits by Thymoquinone

This descriptive study investigates in a rabbit model of atherosclerosis (i) the extent of atherogenesis induced by cyclosporine A (CsA) or hyperlipidemia alone or in combination and (ii) whether thymoquinone (TQ), a known herbal antioxidant, offers protection against these effects. New Zealand White female rabbits were assigned to five groups of six animals each: Group I, control; Group II, CsA [25 mg kg−1 day−1 orally (PO)]; Group III, 1% cholesterol; Group IV, 1% cholesterol + CsA (25 mg kg−1 day−1 PO); and Group V, 1% cholesterol + CsA (25 mg kg−1 day−1 PO) + TQ (10 mg kg−1 day−1 PO). Lipids and oxidative stress parameters [Malondialdehyde (MDA) and protein carbonyl] and aortic atherosclerosis were compared. CsA alone did not show a significant effect on either serum lipids and did not induce atherosclerosis. High-cholesterol diet induced atherosclerosis (45 ± 11% of the intimal surface of aorta was covered with atherosclerotic plaques). CsA and high-cholesterol diet increased atherosclerosis severity as measured from intimal and media lesions, but did not affect the extent of atherosclerosis. TQ decreased aortic MDA by 83%. It was also associated with reduced aortic atherosclerosis extend by 52% compared with Group IV. We concluded that (i) CsA aggravates hyperlipidemia-induced atherosclerosis and (ii) TQ attenuates the oxidative stress and atherogenesis induced by the combined effect of CsA and hyperlipidemia