Zahra Karimi

Alginic acid: a highly efficient renewable and heterogeneous biopolymeric catalyst for one-pot synthesis of the Hantzsch 1,4-dihydropyridines

Alginic acid, a naturally occurring polysaccharide, in its granular form and without any post-modification was found to be an efficient, environmentally benign, easily recoverable and low-cost catalyst for the clean and rapid synthesis of 1,4-dihydropiridine derivatives (DHPs) just based on its polysaccharide architecture. The Hantzsch pseudo-four-component reaction of ethyl or methyl acetoacetate, ammonium acetate and different aldehydes is catalyzed by alginic acid efficiently under mild conditions to afford the desired products in high to quantitative yields and clean reaction profiles. Avoiding the use of any transition metal, the use of a one-pot and multi-component procedure for the synthesis of DHPs, the reusability of the catalyst and operational simplicity are important features of this methodology.

Sodium alginate: An efficient biopolymeric catalyst for green synthesis of 2-amino-4H-pyran derivatives

Sodium alginate, a naturally occurring macromolecule, in its granular form and without any post-modification was found to be an efficient and recoverable bifunctional heterogeneous organocatalyst for the domino synthesis of various 2-amino-3-cyano-4H-pyran annulated derivatives through three-component condensation of different aldehydes, malononitrile and diverse 1,3-dicarbonyl compounds under mild conditions. Corresponding 4H-pyran derivatives were obtained in high to excellent yields after 25-150min stirring in 2mL EtOH under reflux conditions in the presence of 10mol% of sodium alginate, equimolar amounts of aldehydes, malononitrile and 1,3-dicarbonyl compounds. The catalyst was easily separated from the reaction mixture to obtain desired products in excellent purity as shown by FTIR and (1)H NMR spectroscopic methods. Avoiding the use of any transition metal, one-pot and multi-component procedure catalyzed by a renewable biopolymer, the reusability of the catalyst, broad substrate scope and operational simplicity are important features of this methodology for preparation of medicinally important compounds.

Tetraethylammonium 2-(N-hydroxycarbamoyl)benzoate: a powerful bifunctional metal-free catalyst for efficient and rapid cyanosilylation of carbonyl compounds under mild conditions

In contrast to tetrabutylammonium hydroxide, its tetraethylammonium counterpart reacts with N-hydroxyphthalimide to afford tetraethylammonium 2-(N-hydroxycarbamoyl)benzoate (TEAHCB) rather than tetraethylammonium phthalimide-N-oxyl (TEAPINO). TEAHCB contains at the same time benzoate and hydroxycarbamoyl functionalities in a proper geometry to activate reaction components as Lewis basic and Lewis acidic centers, respectively. TEAHCB was found to be able to efficiently catalyze very rapid cyanosilylation of a wide variety of carbonyl compounds at 0.15 mol% catalyst loading under solvent-free conditions at room temperature as a simple and readily available bifunctional organocatalyst.

Chitosan: An efficient biomacromolecule support for synergic catalyzing of Hantzsch esters by CuSO4

The synergic effect of the chitosan biomacromolecule support for catalyzing of Hantzsch esters formation by CuSO4 has been demonstrated for one-pot and efficient pseudo-four-component reaction to afford a wide range of 1,4-dihydropyridine (DHP) or polyhydroquinoline (PHQ) derivatives. The desired products were simply prepared from different aldehydes, β-dicarbonyls and ammonium acetate in the presence of a low loading of chitosan supported copper(II) sulfate (CSCS) in EtOH under reflux conditions. The biodegradable CSCS catalyst was characterized by field emission scanning electron microscopy (FESEM) and energy-dispersive X-ray spectroscopy analysis (EDX) methods as well as coupled plasma-atomic emission (ICP-AE) and FT-IR spectroscopy. The CSCS catalyst is recyclable and reused four times without significant loss of its activity.

MicroRNA 17-92 expressed by a transposone-based vector changes expression level of cell-cycle-related genes.

The miR‐17‐92 cluster is composed of seven miRNAs (microRNAs; miR‐17‐5p, miR‐17‐3p, miR‐18a, miR‐19a, miR‐20a, miR‐19b‐1 and miR‐92a‐1). Previous studies have indicated that this cluster is involved in cell proliferation and their overexpression has been seen in several types of cancer. We have assessed the overexpression effects of miR‐17‐92 on the expression of several genes associated with cell‐cycle regulation. The human miR‐17‐92 gene was cloned into a transposone‐based vector, piggyBac and transfected into HEK‐293T [HEK‐293 cells (human embryonic kidney cells) expressing the large T‐antigen of SV40 (simian virus 40)] cell line. Gene expression analysis indicated that up‐regulation of this cluster causes significant changes in the expression of several cell‐cycle related genes, including CDK2 (cyclin‐dependent kinase 2), cyclin‐D2, c‐Myc and CREB (cAMP‐response‐element‐binding protein). Other methods of transcripts assessment confirmed miR‐17‐92 overexpression enhances cell proliferation.

VMD DisRg: New User-Friendly Implement for calculation distance and radius of gyration in VMD program.

Molecular dynamic simulation is a practical and powerful technique for analysis of protein structure. Several programs have been developed to facilitate the mentioned investigation, under them the visual molecular dynamic or VMD is the most frequently used programs. One of the beneficial properties of the VMD is its ability to be extendable by designing new plug-in. We introduce here a new facility of the VMD for distance analysis and radius of gyration of biopolymers such as protein and DNA. Availability The database is available for free at http://trc.ajums.ac.ir/HomePage.aspx/?TabID/=12618/&Site/=trc.ajums.ac/&Lang/=fa-IR

Alginic acid: A mild and renewable bifunctional heterogeneous biopolymeric organocatalyst for efficient and facile synthesis of polyhydroquinolines

Alginic acid, a widely used naturally occurring carbohydrate which is generally derived from brown seaweeds, can be considered as a bifunctional heterogeneous and green biopolymeric organocatalyst. Alginic acid, without any post-modification with active Bronsted or Lewis acid centers, was found to be a highly active, cost-effective, commercially-available, renewable and recoverable heterogeneous biopolymeric organocatalyst for the expeditious synthesis of polyhydroquinolines (PHQs). Polyhydroquinolines were synthesized from the four-component Hantzsch reaction of ethyl acetoacetate, different aldehydes, ammonium acetate and cyclic 1,3-diones under mild conditions in high to quantitative yields, 75-97%, using alginic acid. Furthermore, alginic acid was found to be reusable for at least 6 consecutive cycles without considerable loss of its catalytic activity.

VMD-SS: A graphical user interface plug-in to calculate the protein secondary structure in VMD program

The investigation on the types of secondary structure (SS) of a protein is important. The evolution of secondary structures during molecular dynamics simulations is a useful parameter to analyze protein structures. Therefore, it is of interest to describe VMD-SS (a software program) for the identification of secondary structure elements and its trajectories during simulation for known structures available at the Protein Data Bank (PDB). The program helps to calculate (1) percentage SS, (2) SS occurrence in each residue, (3) percentage SS during simulation, and (4) percentage residues in all SS types during simulation. The VMD-SS plug-in was designed using TCL script and stride to calculate secondary structure features. Availability The database is available for free at http://science.scu.ac.ir/HomePage.aspx?TabID=13755

Prevalence of and Factors Associated with Migraine in Medical Students at BandarAbbas, Southern Iran, in 2012.

Background: Migraine is one of the most common etiologies for headache. This very common neurological disorder has a significant impact on patients’ quality of life. The aim of the current study is to evaluate the prevalence of migraine among medical students in the Hormozgan University of Medical Sciences (HUMS). Methods: A total of 350 medical students were enrolled in our descriptive study. Data were collected using the standard questionnaire of the International Headache Association. The data were analyzed by SPSS 20.0 software using descriptive statistics, Chi-Square, and Independent Samples T-Test. A P-value of ≥0.05 was considered statistically significant, since most public health professionals use this value as a standard. Results: Among the medical students in our study, 24.6% had experienced frequent, severe headaches. The underlying causes of the headaches were diagnosed in 19.8% of the students. The prevalence of migraine in our study was 16.3% (mean age=21.28±2.71years). The prevalence varied by gender, and it was greater among male students. Conclusion: Our findings indicated that there was a high prevalence of migraine among the medical students in our study, and these findings were consistent with those of previous studies in Iran and other countries.

64 Cu, a powerful positron emitter for immunoimaging and theranostic: Production via nat ZnO and nat ZnO-NPs

64Cu is one of the most beneficial radionuclide that can be used as a theranostic agent in Positron Emission Tomography (PET) imaging. In this current work, 64Cu was produced with zinc oxide nanoparticles (natZnONPs) and zinc oxide powder (natZnO) via the 64Zn(n,p)64Cu reaction in Tehran Research Reactor (TRR) and the activity values were compared with each other. The theoretical activity of 64Cu also was calculated with MCNPX-2.6 and the cross sections of this reaction were calculated by using TALYS-1.8, EMPIRE-3.2.2 and ALICE/ASH nuclear codes and were compared with experimental values. Transmission Electronic Microscopy (TEM), Scanning Electronic Microscopy (SEM) and X-Ray Diffraction (XRD) analysis were used for samples characterizations. From these results, its concluded that 64Cu activity value with nanoscale target was achieved more than the bulk state target and had a good adaptation with the MCNPX result.