Dissolution mechanism of colemanite in sulphuric acid solutions

Aycan G?r 한국화학공학회 2007 Korean Journal of Chemical Engineering Vol.24 No.4

compounds are very important raw materials in many branches of industry and their uses have beenincreasing and expanding continuously. Colemanite, one of the most common boron minerals, has a monoclinic crystalstructure with a chemical formula of 2CaO·3B2O3·5H2O and is used usually in the production of boric acid. The present2SO4 solution and the efect of acidconcentration, the effect of SO42 ion on the dissolution process, using H2SO4, HCI+H2SO4 and H2SO4+Na2SO4 solu-tions. The analysis of the experimental data shows that increasing H3O+ acid concentration increased the dissolutionrate, but increasing SO42 concentration reduced dissolution rate because of the precipitation of a solid film of CaSO4and CaSO4·H2O.

Difficulties experienced by endodontics researchers in conducting studies and writing papers

Alim-Uysal Betul Aycan,Goker-Kamali Selin,Machado Ricardo 대한치과보존학회 2022 Restorative Dentistry & Endodontics Vol.47 No.2

Objectives The study investigated the difficulties experienced by endodontics researchers around the world in conducting studies and writing papers. Materials and Methods A survey consisting of 18 questions on the difficulties experienced by endodontics researchers in performing studies and writing papers was e-mailed to academics in the field of endodontics working at 202 universities. The independent risk factors were analyzed using binary logistic regression at a significance level of 0.05. Results A total of 581 individuals (10.7%) agreed to participate in the study. Almost half the participants (48.2%) reported that they had received some type of training in conducting studies and writing papers. In response to the question, “Do you get help from a statistician to perform the statistical analyses of your studies?,” 77.1% answered “yes.” Around 40% of the participants stated that the need to obtain ethical approval negatively affected their desire to conduct studies. The participants’ regions had no effect on the reported difficulties associated with writing papers in English or conducting statistical analyses (p > 0.05). Most participants (81.8%) reported difficulties in writing the Discussion section, regardless of their region, academic degrees, or years of experience. Conclusions The participants stated they experienced difficulties in many areas, such as conducting statistical analyses, finding new ideas, and writing in English. Engaging in a detailed examination of ethics committee rules, expanding biostatistics education, increasing the number of institutions providing research funding, and increasing the number of endodontics journals can increase the enthusiasm of endodontics researchers to publish papers.

Monte Carlo approach for calculation of mass energy absorption coefficients of some amino acids

Bozkurt, Ahmet,Sengul, Aycan Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.9

This study offers a Monte Carlo alternative for computing mass energy absorption coefficients of any material through calculation of photon energy deposited per mass of the sample and the energy flux obtained inside a sample volume. This approach is applied in this study to evaluate mass energy absorption coefficients of some amino acids found in human body at twenty-eight different photon energies between 10 keV and 20 MeV. The simulations involved a pencil beam source modeled to emit a parallel beam of mono-energetic photons toward a 1 mean free path thick sample of rectangular parallelepiped geometry. All the components in the problem geometry were surrounded by a 100 cm vacuum sphere to avoid any interactions in materials other than the absorber itself. The results computed using the Monte Carlo radiation transport packages MCNP6.2 and GAMOS5.1 were checked against the theoretical values available from the tables of XMUDAT database. These comparisons indicate very good agreement and support the conclusion that Monte Carlo technique utilized in this fashion may be used as a computational tool for determining the mass energy absorption coefficients of any material whose data are not available in the literature.

A novel sulfonated aromatic polyimide synthesis and characterization: Energy calculations, QTAIM simulation study of the hydrated structure of one unit

Yildiko Umit,Tanriverdi Aslihan Aycan 대한화학회 2022 Bulletin of the Korean Chemical Society Vol.43 No.6

A new type of sulfonated polyimide was synthesized from a one-step polycondensation reaction with perylene-3,4,9,10-tetracarboxylic dianhydride and 4,40- diamino-2,20-stilbenedisulfonic. Pure characterization of sulfonated polyimide (SPI) was performed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, thermogravimetric analysis, differential thermal gravimetric analysis, ultraviolet–visible spectroscopy, and solubility tests. Moreover, the SPI film was prepared by a thermal imidization step heating procedure. Furthermore, quantum chemical calculations of the synthesized SPI were investigated with density functional theory (DFT) and time-dependent density functional theory. By calculating the frontiers molecular orbital energies of the obtained polyimide, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), and the energy gap (Δ) values were found for the one structural unit and three structural units of SPI, respectively. Also, QTAIM was carried out based on the AIMAll program. With the increase in water molecules, the average electronic energy density (HBCP) value decreased according to the results of QTAIM. The SPI can be used as a potential membrane in fuel cells.

A New Radiological Sign for Severe Angular Kyphosis: “The Baltalimani Sign”

Yunus Atici,Osman Emre Aycan,Muhammed Mert,Deniz Kargin,Akif Albayrak,Mehmet Bulent Balioglu 대한척추외과학회 2016 Asian Spine Journal Vol.10 No.6

Study Design: Retrospective diagnostic study. Purpose: To define a new radiological sign, “Baltalimani sign,” in severe angular kyphosis (SAK) and to report its relationship with the risk of neurological deficits and deformity severity. Overview of Literature: Baltalimani sign was previously undefined in the literature. Methods: We propose Baltalimani sign as the axial orientation of the vertebrae that are located above or below the apex of angular kyphosis on anteroposterior radiographs. Patients with SAK of various etiologies with kyphotic angles ≥90° were selected and evaluated for the presence of Baltalimani sign. Demographic data of the patients including age, gender, etiology, neurological status, local kyphosis angles, and the location of the kyphosis apex were recorded. Sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV) of Baltalimani sign for the risk of the neurological deficits were evaluated by the IBM SPSS ver. 20.0. A p -values of <0.05 were considered statistically significant. Cohen’s kappa was used for analysis of interrater agreement. Results: The mean local kyphosis angle in all patients was 124.2° (range, 90°–169°), and 15 of 40 (37.5%) patients had neurological deficits. Baltalimani sign was seen in 13 of 15 patients with neurological deficits (p =0.001). Baltalimani sign showed a sensitivity and specificity PPV and NPV of 61.9%, 86.7%, 89.5%, and 68.8% for the risk of the neurological deficits in SAK patients, respectively. Cohen’s kappa value was moderate (κ=0.506). Conclusions: The detection of Baltalimani sign in SAK may indicate severity of deformity and the risk of neurological deficits.

Tracking acute phase protein response during acute and chronic Toxoplasma gondii infection

Hasan Tarik Atmaca,Aycan Nuriye Gazyagci,Osman Safa Terzi,Gungor Cagdas Dincel,Tugce Sumer 한국실험동물학회 2019 Laboratory Animal Research Vol.35 No.2

Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii, which occurs worldwide in mammals and birds. Brain is the primary target organ because Toxoplasma gondii is a ubiquitous intracellular parasite that causes most frequently life-threatening encephalitis in immunocompromised patients. Relation of tissue cysts number, histopathology score and acute phase proteins were investigated. In this study, 36 mice are infected with Me49 strain of Toxoplasma gondii. The control group has 6 healthy mice. After inoculation of Toxoplasma gondii, at 10., 15., 20., 30., 45., 60. days, 6 each mice euthanized after collection of blood samples. Hemopexin, haptoglobulin, macroglobulin, serum amyloid A and clusterin levels are determined by ELISA. Then, brain tissues were investigated histopathologically and lesions were scored. The average cyst numbers were determined by counting three samples (25 μl each) of each brain homogenate under light microscopy. Inflammatory reaction was observed on day 10 days after inoculation (d.a.i.) The lesions were characterized by perivascular mononuclear cell infiltration, focal mononuclear cell infiltration in the meninges, and glial proliferation. Tissue cysts were observed in all Toxoplasma gondii-infected groups. The highest lesion score was observed at 60 d.a.i. And the most tissue cyst number were on day 30. d.a.i. Serum levels of hemopexin, haptoglobulin, macroglobulin, serum amyloid A and clusterin were significantly higher than the control group on day 10–20., 10., 10–30., 10.,10–45 d.a.i., respectively. High level of acute phase proteins in mice on certain days infected with Toxoplasma gondii was exhibited a relationship between brain lesions and tissue cysts.

A novel method for high-frequency transgenic shoot regeneration via Agrobacterium tumefaciens in flax (Linum usitatissimum L.)

Beyaz, Ramazan,Darcin, E. Selcen,Aycan, Murat,Kayan, Mustafa,Yildiz, Mustafa The Korean Society of Plant Biotechnology 2016 식물생명공학회지 Vol.43 No.2

In this study, routinely used transformation method, which includes transferring explants onto co-cultivation medium after inoculating them with bacterial solution for a while, was compared with 3 different inoculation methods. In every 3 methods, hypocotyl explants excised from 7-day-old sterile flax seedlings having cotyledon leaves and no root system dried under air flow in sterile cabin for 35 min were inoculated with different volumes of bacterial solution at different inoculation periods. GV2260 line of Agrobacterium tumefaciens having 'pBIN 19' plasmid containing npt II (neomycin phosphotransferase II) gene and GUS reporter gene was used in transformation studies. After inoculation, hypocotyl segments of seedlings (0.5 cm in length) - were excised and left to co-cultivation for 2 days. Then, explants were transferred to regeneration medium supplemented with different antibiotics. The presence of npt-II and GUS genes in transformants was confirmed by PCR and GUS analysis. The highest results in all characters examined in all cultivars were obtained from the 2 inoculation method in which hypocotyls excised from seedlings inoculated with $500{\mu}l$ of bacterial solution after drying in sterile cabin for 35 min were used.

A novel method for high-frequency transgenic shoot regeneration via Agrobacterium tumefaciens in flax (Linum usitatissimum L.)

Ramazan Beyaz,E. Selcen Darçın,Murat Aycan,Mustafa Kayan,Mustafa Yıldız 한국식물생명공학회 2016 JOURNAL OF PLANT BIOTECHNOLOGY Vol.43 No.2

In this study, routinely used transformation method, which includes transferring explants onto co-cultivation medium after inoculating them with bacterial solution for a while, was compared with 3 different inoculation methods. In every 3 methods, hypocotyl explants excised from 7-day-old sterile flax seedlings having cotyledon leaves and no root system dried under air flow in sterile cabin for 35 min were inoculated with different volumes of bacterial solution at different inoculation periods. GV2260 line of Agrobacterium tumefaciens having ‘pBIN 19’ plasmid containing npt II (neomycin phosphotransferase II) gene and GUS reporter gene was used in transformation studies. After inoculation, hypocotyl segments of seedlings (0.5 cm in length) - were excised and left to co-cultivation for 2 days. Then, explants were transferred to regeneration medium supplemented with different antibiotics. The presence of npt-II and GUS genes in transformants was confirmed by PCR and GUS analysis. The highest results in all characters examined in all cultivars were obtained from the 2 inoculation method in which hypocotyls excised from seedlings inoculated with 500 μl of bacterial solution after drying in sterile cabin for 35 min were used.

Characterisation of Phenotypic and Genotypic Antibiotic Resistance Profile of Enterococci from Cheeses in Turkey

Kurekci, Cemil,Onen, Sevda Pehlivanlar,Yipel, Mustafa,Aslantas, Ozkan,Gundogdu, Aycan Korean Society for Food Science of Animal Resource 2016 한국축산식품학회지 Vol.36 No.3

The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3’)-IIIa, ant(6)-Ia and aac(6’)-Ieaph(2”)-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey.

Characterisation of Phenotypic and Genotypic Antibiotic Resistance Profile of Enterococci from Cheeses in Turkey

Cemil Kürekci,Sevda Pehlivanlar Önen,Mustafa Yipel,Özkan Aslantas,Aycan Gündogdu 한국축산식품학회 2016 한국축산식품학회지 Vol.36 No.3

The aim of this study was to determine the prevalence of enterococci in cheese samples and to characterize their antimicrobial resistance profiles as well as the associated resistance genes. A total of 139 enterococci were isolated from 99 cheese samples, the isolates were identified as E. faecalis (61.2%), E. faecium (15.1%), E. gallinarum (12.9%), E. durans (5.0%), E. casseliflavis (2.9%) and E. avium (2.9%). The most frequent antimicrobial resistance observed in enterococci isolates was to lincomycin (88.5%), followed by kanamycin (84.2%), gentamycin (low level, 51.1%), rifampin (46.8%) and tetracycline (33.8%). Among the isolates, the frequencies of high level gentamycin and streptomycin resistant enterococci strains were 2.2% and 5.8%, respectively. Apart from the mentioned antibiotics, low levels of resistance to ciprofloxacin, erythromycin and chloramphenicol were found. Moreover no resistance was observed against penicillin and ampicillin. The antimicrobial resistance genes including tetM, tetL, ermB, cat, aph(3’)-IIIa, ant(6)-Ia and aac(6’)-Ieaph(2’’)-Ia were found in enterococci from Turkish cheese samples. In the current study, we provided data for antibiotic resistance and the occurrence of resistance genes among enterococci. Regulatory and quality control programs for milk and other dairy products from farms to retail outlets has to be established and strengthened to monitor trends in antimicrobial resistance among emerging food borne pathogens in Turkey.