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    Spectrophotometric determination of sulfide based on peroxidase inhibition by detection of purpurogallin formation

    , Article Ecotoxicology and Environmental Safety ; Volume 91 , 2013 , Pages 117-121 ; 01476513 (ISSN) Ghadiri, M ; Kariminia, H. R ; Roosta Azad, R ; Sharif University of Technology
    This paper presents a new method for spectrophotometirc detection of sulfide applying fungal peroxidase immobilized on sodium alginate. The sensing scheme was based on decrease of the absorbance of the orange compound, purpurogallin produced from pyrogallol and H2O2 as substrates, due to the inhibition of peroxidase by sulfide. Absorbance of purpurogallin was detected at 420nm by using a spectrophotometer. The proposed method could successfully detect the sulfide in the concentration range of 0.6-7.0μM with a detection limit of 0.4μM. The kinetic parameters of Michaelis-Menten with and without sulfide were also calculated. Possible inhibition mechanism of peroxidase by sulfide was deduced... 

    Effect of hydrogen bonds on pK a values: Importance of networking

    , Article Journal of the American Chemical Society ; Volume 134, Issue 25 , 2012 , Pages 10646-10650 ; 00027863 (ISSN) Shokri, A ; Abedin, A ; Fattahi, A ; Kass, S. R ; Sharif University of Technology
    The pK a of an acyclic aliphatic heptaol ((HOCH 2CH 2CH(OH)CH 2) 3COH) was measured in DMSO, and its gas-phase acidity is reported as well. This tertiary alcohol was found to be 10 21 times more acidic than tert-butyl alcohol in DMSO and an order of magnitude more acidic than acetic acid (i.e., pK a = 11.4 vs 12.3). This can be attributed to a 21.9 kcal mol -1 stabilization of the charged oxygen center in the conjugate base by three hydrogen bonds and another 6.3 kcal mol -1 stabilization resulting from an additional three hydrogen bonds between the uncharged primary and secondary hydroxyl groups. Charge delocalization by both the first and second solvation shells may be used to facilitate... 

    Electrocatalytic CO2 fixation by regenerating reduced cofactor NADH during calvin cycle using glassy carbon electrode

    , Article PLoS ONE ; Volume 15, Issue 9 September , 2020 Ali, I ; Amiri, S ; Ullah, N ; Younas, M ; Rezakazemi, M ; Sharif University of Technology
    Public Library of Science  2020
    In this study, an enzymatic pathway has been developed to replicate the Calvin Cycle by creating the individual steps of the carbon cycle in a bioreactor. The technology known as “artificial photosynthesis” converts CO2 emissions into a variety of intermediates that serve as precursors to high-value products. CO2, light, water, and electricity were used as feedstock. An electrochemical reactor was also studied for the regeneration of active NADH operating at constant electrode potential. Initially, a batch electrochemical reactor containing 80 mL of 0.2 mM NAD+ in Tris-buffer (pH 7.40) was used to evaluate the electrode material operating at normal temperature and pressure. The results... 

    Involvement of TGF-β and autophagy pathways in pathogenesis of diabetes: a comprehensive review on biological and pharmacological insights

    , Article Frontiers in Pharmacology ; Volume 11 , 15 September , 2020 Heydarpour, F ; Sajadimajd, S ; Mirzarazi, E ; Haratipour, P ; Joshi, T ; Farzaei, M. H ; Khan, H ; Echeverria, J ; Sharif University of Technology
    Frontiers Media S.A  2020
    Despite recent advancements in clinical drugs, diabetes treatment still needs further progress. As such, ongoing research has attempted to determine the precise molecular mechanisms of the disorder. Specifically, evidence supports that several signaling pathways play pivotal roles in the development of diabetes. However, the exact molecular mechanisms of diabetes still need to be explored. This study examines exciting new hallmarks for the strict involvement of autophagy and TGF-β signaling pathways in the pathogenesis of diabetes and the design of novel therapeutic strategies. Dysregulated autophagy in pancreatic β cells due to hyperglycemia, oxidative stress, and inflammation is associated... 

    Stimulus-responsive sequential release systems for drug and gene delivery

    , Article Nano Today ; Volume 34 , 2020 Ahmadi, S ; Rabiee, N ; Bagherzadeh, M ; Elmi, F ; Fatahi, Y ; Farjadian, F ; Baheiraei, N ; Nasseri, B ; Rabiee, M ; Tavakoli Dastjerd, N ; Valibeik, A ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
    Elsevier B.V  2020
    In recent years, a range of studies have been conducted with the aim to design and characterize delivery systems that are able to release multiple therapeutic agents in controlled and programmed temporal sequences, or with spatial resolution inside the body. This sequential release occurs in response to different stimuli, including changes in pH, redox potential, enzyme activity, temperature gradients, light irradiation, and by applying external magnetic and electrical fields. Sequential release (SR)-based delivery systems, are often based on a range of different micro- or nanocarriers and may offer a silver bullet in the battle against various diseases, such as cancer. Their distinctive...