MicroRNAs are reported to have a crucial role in the regulation of self-renewal and differentiation of stem cells. Hypoxia has been identified as a key biophysical element of the stem cell culture milieu however, the link between hypoxia and miRNA expression in stem cells remains poorly understood. We therefore explored miRNA expression in hypoxic human embryonic and mesenchymal stem cells (hESCs and hMSCs). A total of 50 and 76 miRNAs were differentially regulated by hypoxia (2% O2) in hESCs and hMSCs, respectively, with a negligible overlap of only three miRNAs. We found coordinate regulation of precursor and mature miRNAs under hypoxia suggesting their regulation mainly at transcriptional level. Hypoxia response elements were located upstream of 97% of upregulated hypoxia regulated miRNAs (HRMs) suggesting hypoxia-inducible-factor (HIF) driven transcription. HIF binding to the candidate cis-elements of specific miRNAs under hypoxia was confirmed by Chromatin immunoprecipitation coupled with qPCR. Role analysis of a subset of upregulated HRMs identified linkage to reported inhibition of differentiation while a downregulated subset of HRMs had a putative role in the promotion of differentiation. MiRNA-target prediction correlation with published hypoxic hESC and hMSC gene expression profiles revealed HRM target genes enriched in the cytokine:cytokine receptor, HIF signalling and pathways in cancer. Overall, our study reveals, novel and distinct hypoxia-driven miRNA signatures in hESCs and hMSCs with the potential for application in optimised culture and differentiation models for both therapeutic application and improved understanding of stem cell biology.

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Zinc, Copper, Selenium, Magnesium, Manganese, Chromium, Iron, Nickel, Cobalt, Vanadium and Germanium were determined by atomic absorption spectrophotometer (AAS) in blood serum of patients with rheumatoid arthritis, (30) patients (14male and 16female) with age range (37-60) years compared with normal tensive control. The analysis of results showed that the mean value of concentration (Magnesium,  Manganese and Nickel) were significantly higher in patients with rheumatoid arthritis compared to that of healthy, while the mean levels of serum (Zinc, Copper, Selenium, Chromium, Iron, Cobalt and Germanium) were significantly lower than controls. There were no significant changes in overall mean concentration of serum Vanadium in patients with rheumatoid arthritis and control group. There were no significant variations in trace elements levels in relation to sex.Our results suggest that low level of trace elements of Zinc, Copper, Selenium, Chromium, Iron, Cobalt and Germanium , and high levels of Magnesium, Manganese and Nickel may provide good clues to the physician about the high probability of the individual for developing of rheumatoid arthritis disease unless the imbalance of these elements in blood serum to be corrected. Key words: Trace elements, Rheumatoid arthritis,Atomic absorption spectrophotometer (AAS).

-Remediation of oil-polluted water from waste lubricating oil by adsorption was investigated using pomegranate peels powder. Many parameters such as the oil sorption capacity, oil retention, water and oil uptake, kinetic behavior of remediation process, adsorption isotherm model, and reusability were studied. The oil sorption capacity of adsorbent was equal to 2.316 g oil /g sorbent. The sorbent has a very good retention time; it can keep 48% of the adsorbed oil after three minutes of drainage. This property makes the material a unique behavior to keep the oil for this long time. The reusability of sorbents showed a 76.2 % of the sorption capacity after 6 reusability cycles. The total amount of adsorbed oil is 11.659 g oil/ g pomegranate peels powder. The kinetic study showed that the rate of adsorption followed the first order kinetics. Langmuir, Frendlich adsorption isotherm models were applied to check if any of these models is fitting the adsorption remediation process.