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마침내 마음을 변화시켰다: 평행사변형을 분류하는데 필요한 반힐레 3 수준을 우회하는 방법
Hagar Gal,류희찬 한국교원대학교 교육연구원 2008 敎員敎育 Vol.24 No.2
This study describes a theory-based instructional approach that aimed to overcome the gap between the geometrical level of thinking (van Hiele) expected in given assignments and students' level of thinking. The research formulated a method that enabled students who did not reach van Hiele’s level 3 (Order) to classify special parallelograms via conceptual behavior. Korean ninth-grade low achievers were introduced to parallelograms in a process involving dynamic and continuous shape changes of multi-named-objects in order to enlarge the concept image. The results of the study seem promising. 본 연구는 주어진 과제에서 기대되는 기하학적 사고 발달 수준과 학생들의 실제적인 사고 수준 사이의 갭을 줄이고자 시도된 수업 실험이 결과를 보여주고 있다. 반힐레 수준 3에 미치지 못한 학생들을 대상으로 다양한 평행사변형을 분류할 수 있도록 하는 교수학적 방법을 개발하여 실험을 한 결과 매우 성공적인 결과를 얻었다. 낮은 성취수준에 있는 우리나라 중학교 3학년 학생들에게 다중으로 명명될 수 있는 대상(평행사변형)을 연속적이고도 역동적으로 변화시키는 과정을 통해 학생들의 개념 이미지가 확장되는 것을 알 수 있었다.
Biodegradation and decolorization of azo dyes by adherent Staphylococcus lentus strain
Kamel Chaieb,Mohamed Hagar,Nagi R. E. Radwan 한국응용생명화학회 2016 Applied Biological Chemistry (Appl Biol Chem) Vol.59 No.3
A Staphylococcus lentus strain, isolated from Red sea water, was tested for decolorization capacity of Congo red, Evans blue, and Eriochrome Black T azo dyes. Biodegradation (100 mgl−1) of these dyes was studied within 24 h in Mineral Salt Medium solution containing 0.10 % (w/v) yeast extract and 7 mM of glucose at a pH of 7.2 and a temperature of 37 °C. Using a 2.2 × 106 CFU/mL inoculum size, S. lentus was able to decolorize these azo dyes with different degree. The staphylococcal biomass achieves approximately 100 % decolorization of Congo red and Eriochrome Black T by the end of treatment. FTIR and UV–Vis analyses confirm biodegradation potential of the tested strain. Moreover, the phytotoxicity of the dye solutions resulting from this treatment shows lower toxic nature compared to untreated solution of the respective dyes.
Synthesis of Asymmetric Pyrazoline Derivatives from Phenylthiophenechalcones; DFT Mechanistic Study
Aboelnaga, Asmaa,Mansour, Eman,Ahmed, Hoda. A.,Hagar, Mohamed Korean Chemical Society 2021 대한화학회지 Vol.65 No.2
New phenylthiophenechalcones,1-(biphenyl-4-yl)-3-(5-phenylthiophen-2-yl)prop-2-en-1-one (3a) and 3-(5-phenylthiophen-2-yl)-1-(4-(piperidin-1-yl) phenyl) prop-2-en-1-one (3b) were synthesized, next, their treatment with thiosemicarbazide in ethanol afforded their pyrazoline derivatives (4a) and (4b), respectively. The molecular structures of the synthesized compounds were confirmed via elemental analysis, FT-IR, 1H, 13C NMR and mass spectroscopy. The geometrical elucidation of four suggested conformers has been studied for these compounds. DFT calculations have been performed to study the stability and the structural parameters of the predicted conformers and revealed that orientation of the biphenyl and the phenylthiophene moieties affect the stability of the estimated conformers of the synthesized chalcones and pyrazoline. Moreover, two reaction mechanisms have been proposed to illustrate the reaction products and the DFT calculations have been used to confirm the reaction mechanism of the pyrazoline compounds.
Bioactivity of Metabolites from Actinomycetes Isolates from Red Sea, Egypt
Osman, Mohamed E.,El-nasr, Amany A. Abo,Hussein, Hagar M,Hamed, Moaz M The Korean Society for Microbiology and Biotechnol 2022 한국미생물·생명공학회지 Vol.50 No.2
Actinomycetes isolated from marine habitats represent a promising source of bioactive substances. Here, we report on the isolation, identification, productivity enhancement and application of the bioactive compounds of Streptomyces qinglanensis H4. Eighteen marine actinomycetes were isolated and tested for resistance to seven bacterial diseases. Using 16S rRNA sequencing analysis (GenBank accession number MW563772), the most powerful isolate was identified as S. qinglanensis. Although the strain produced active compound(s) against a number of Gram-negative and Gram-positive bacteria, it failed to inhibit pathogenic fungi. The obtained inhibition zones were 22.0 ± 1.5, 20.0 ± 1, 16.0 ± 1, 12.0 ± 1, 22.0 ± 1 and 24.0 ± 1 mm against Bacillus subtilis ATCC 6633, Escherichia coli ATCC 19404, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 9027, Candida albicans ATCC 10231 and Staphylococcus aureus ATCC6538, respectively. To maximize bioactive compound synthesis, the Plackett-Burman design was used. The productivity increased up to 0.93-fold, when S. qinglanensis was grown in optimized medium composed of: (g/l) starch 30; KNO<sub>3</sub> 0.5; K<sub>2</sub>HPO<sub>4</sub> 0.25; MgSO<sub>4</sub> 0.25; FeSO<sub>4</sub>·7H<sub>2</sub>O, 0.01; sea water concentration (%) 100; pH 8.0, and an incubation period of 9 days. Moreover, the anticancer activity of S. qinglanensis was tested against two different cell lines: HepG2 and CACO. The inhibition activities were 42.96 and 57.14%, respectively. Our findings suggest that the marine S. qinglanensis strain, which grows well on tailored medium, might be a source of bioactive substances for healthcare companies.
Ahmed Farid Al-Neklawy,Nagwa Ebrahim El-Nefiawy,Hagar Yousry Rady 대한해부학회 2022 Anatomy & Cell Biology Vol.55 No.1
In this study, the effect of oral ciprofloxacin on the structure of the thoracic aorta in rats was investigated. Twenty four male albino rats were divided into 4 groups (6 rats/group): group I (adult control), group II (adult rats treated with ciprof loxacin), group III (senile control), and group IV (senile rats treated with ciprof loxacin). Rats in groups II and IV received ciprofloxacin via oral gavage in a daily dose of 3.5 mg/kg/d for 14 days, while control rats received equivalent amount of distilled water used to dissolve the drug. After 2 weeks, all rats were sacrificed, thoracic aortae were dissected, and half of the specimens were processed for paraffin sections and examined by light microscopy. The other half of the specimens were prepared for scanning electron microscopy. Sections from rats treated with ciprofloxacin showed evident damaging effect on aortic wall particularly in (group IV). Aortic intima showed, focal desquamation of the lining epithelium. Tunica media exhibited loss of the normal concentric arrangement and degeneration of the smooth muscle cells. Immune staining for alpha smooth muscle actin showed muscle damage. Interestingly, some sections in (group IV) showed out-pouch (aneurysm like) of the aortic wall. There was dense collagen fibers deposition. Scanning electron microscopic observations of (group IV) revealed uneven intima, adherent blood cells and fibrin filaments to damaged intima, and out-pouch formation. It was concluded that oral ciprofloxacin caused deleterious structural changes in the thoracic aortic wall of rats explaining clinical observations of fluoroquinolones induced risk of aortic dissection and aneurysm.
Synergistic Activity of Paclitaxel and Sorafenib Against Liver Cancer Stem Cells
( Hend M. Nawara ),( Said M. Afify ),( Ghmkin Hassan ),( Maram H. Zahra ),( Marwa N. Atallah ),( Hager Mansour ),( Hagar A. Abu Quora ),( Amira Osman ),( Hiroki Kakuta ),( Hiroki Hamada ),( Akimasa Se 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1
Aims: Cancer stem cells (CSCs), also known as tumor-initiating cells (TICs), are suggested to be responsible for drug resistance and cancer recurrence. Current treatments with conventional chemotherapy are not highly efficient against the cancer stem cells (CSCs). The combination of anticancer drugs, of which functions are different from the other, enhances efficiency compared to the mono-therapy because it targets cancer cells in a synergistic or an additive manner. In this study, the effect of paclitaxel and sorafenib on cancer stem cells (CSCs) developed from mouse iPSCs in very low concentration was evaluated. Methods: To investigate the effect of combination therapy, CSCs were exposed to paclitaxel and/or sorafenib at different concentrations of 1, 2 and 4 nM, respectively. Cell viability was assessed with 3-(4,5-dimethylthiazolyl)-2,5-diphenyltetrazolium bromide (MTT). The same concentrations of the agents were assessed for the effect on the self-renewal potential of CSCs subpopulation by sphere formation ability. Results: As a result, a combination of sorafenib and paclitaxel significantly reduced the resistance while the CSCs exhibited drug resistance against paclitaxel alone. Also, combination of these agents reduces the self-renewal potential of CSCs when compared to single treatment. Simultaneously, combination significantly suppressed not only the colony formation but also the tube formation of the Cancer stem cells. Conclusions: These results suggest the combination therapy of paclitaxel and sorafenib in low doses be an attractive approach to target cancer stem cells in the future.