Synthesis and pancreatic lipase inhibitory activities of some 1,2,4-triazol-5(3)-one derivatives

In this study, starting from 4-amino-5-(4-chlorobenzyl)-2,4-dihydro-3H-1,2,4-triazole-3-one ( 1 ), the 4-Amino-5-(4-chlorobenzyl)-2-undecyl-2,4-dihydro-3H-1,2,4-triazol-3-one ( 2 ) was first synthesized and this compound was converted to Schiff base derivatives ( 3a-e ). In the second step of the study, the 2-[3-(4-chlorobenzyl)-5-oxo-1-undecyl-1,5-dihydro-4H-1,2,4-triazole-4-yl]-acetohydrazide ( 6 ), which was used as a key product in the synthesis of many heterocyclic compounds was synthesized in four steps, and then this compound was converted into methylidene acetohydrazide ( 7a-e ), thiosemicarbazide ( 8a-e ), and 1,2,4-triazole-5-thione ( 9a-e ) derivatives. Also, in the last part of the study, 1,2,4-triazole-5-thione derivatives were changed into Mannich bases ( 10a-b ) bearing a 4-phenylpiperazine ring. These new compounds were tested with regard to pancreatic lipase (PL) inhibition activity, and compound 3b , 3d , 7d , 8d , and 9d showed a considerable anti-lipase activity at various concentrations. The activity of compounds 7b (IC₅₀ = 1.45 ± 0.12 μM) was the highest in terms of IC₅₀, comparable to that of orlistat, a well-known PL inhibitor used as an antiobesity drug.     

Structural and adsorption behaviour of ZnO/aminated SWCNT-COOH for malachite green removal: face-centred central composite design

In this study, an effective adsorbent was synthesized to remove malachite green (MG), which is one of the toxic dyes. Firstly, single walled carbon nanotube with carboxylated acid (SWCNT-COOH) was functionalized with diethylenetriamine and a new nanocomposite was obtained using nano zinc oxide (ZnO) powder. The effects of pH (3–7), the amount of adsorbent (5–15 mg) and the initial concentration (10–50 mg L^–1) of the solution on the adsorption uptake were investigated. The optimal parameters that maximize the adsorption uptake according to the specified working range are found to be 4.63 for pH, 49.94 mg L^–1 for initial concentration, 5.25 mg for the adsorbent dose, and the maximum adsorption capacity has been found as 52.26 mg g^–1. The excellent fitting of the pseudo-second kinetic model with (R² = 0.9912) was fitted the experimental data. The Freundlich isotherm model gave a clue about the type of adsorption. Furthermore, thermodynamic results showed that adsorption process was endothermic.     

Combination of the Particle Size Distributions of Some Industrial Minerals Measured by Andreasen Pipette and Sieving Techniques

It is known that size of the individual particles is the predominant factor affecting the behavior of particulate materials, and that the size effects become increasingly important as the particles become finer. In this article, particle size distributions (PSDs) measured by different techniques, i.e. sieving and Andreasen pipette sedimentation, were combined for different mill (ball and rod) products of some industrial (talc and quartz) minerals. The corrected sedimentation data came closer to the sieving data. The apparent mean shape factors, r, determined from the corrected PSDs for the talc mineral ground by ball and rod mill were found to be 1.34, 0.62, whereas it was 1.00, 1.12 for the quartz mineral ground by ball and rod mill, respectively. The results show that the ball milled products of talc mineral have more regular (rounder in shape) particles than those of rod milled, but the rod milled products of quartz mineral studied were not more regular in shape than ball milled products of quartz mineral as confirmed by the SEM pictures and reviewed literature.     

Understanding kindergarten teachers’ perspectives of teaching basic geometric shapes: a phenomenographic research

Geometry is one of the disciplines children involve within early years of their lives. However, there is not much information about geometry education in Turkish kindergarten classes. The current study aims to examine teachers’ perspectives on teaching geometry in kindergarten classes. The researchers inquired about teachers’ in-class experiences in geometry and asked a series of questions such as “what are the benchmarks in your kindergarten class?”; “what kind of tools and materials you use to teach geometry in your class?”; “what shape do you teach first in your kindergarten class?”; “what do you expect to hear when you asked your students ‘what is square’?”; “how do you teach rectangular?”. The study utilized one of the qualitative research methods, namely phenomenography, to collect the data and analyze the data. The study involved with eight kindergarten teachers who work in different schools in central Kutahya, Turkey. The researchers collected data by conducting face-to-face half-structured interviews. The findings of this phenomenographic research showed that kindergarten teachers have some difficulties in teaching geometry and have lack of knowledge and skills in teaching geometry in kindergarten classes.     

Effect of pressure on pressed pellets in XRS

In this study, the absorption experiments which are an application area in XRS are discussed. The effect on the absorption parameters of the pressure applied to make pellet powder samples was investigated. The mass attenuation coefficients ( μ _m ), mean free paths and half-value layers of samples prepared at different pressures were experimentally determined. C₆H₁₀O₅, VF₄, CaO and Y₂O₃ samples were pressed at 1.91, 3.82, 5.72 and 7.63 tons/cm². A variable energy x-ray source from Amersham (AMC.2084) was used in order to irradiate the samples at energies 13.39, 19.63, 24.90, 32.06, 36.39, 44.48, 51.70 and 59.54 keV. The photon intensities were measured by using an HPGe detector with a resolution of 182 eV at 5.9 keV. The theoretical radiation absorption parameters were calculated by WinXCOM program. The calculated values were compared with the experimental values. Good agreement has been observed within experimental uncertainties for low pellet pressure. The obtained results show that the radiation absorption parameters change with the amount of pressure applied to the sample.     

Monodisperse Mw-Pt NPs@VC as Highly Efficient and Reusable Adsorbents for Methylene Blue Removal

Addressed herein, monodisperse Vulcan carbon supported Pt nanoparticles (Mw-Pt NPs@VC) have been reproducibly synthesized using the microwave assisted method and their application for methylene blue (MB) removal from aqueous solutions was investigated through the adsorption mechanism. The prepared nanomaterials were characterized by X-ray diffraction, transmission electron microscopy, high resolution transmission electron microscopy and X-ray photoelectron spectroscopy. All results show that highly crystalline and colloidally stable nanoparticles have been formed and Mw-Pt NPs@VC were found to be one of the the most active catalyst. The results showed that the Mw-Pt NPs@VC nanoparticles had remarkable MB adsorption capacity of 271.15 mg/g. The equilibrium for MB adsorption was attained in ～55 min. Moreover, Mw-Pt NPs@VC is a reusable and promising material for MB removal since it preserves 95.6 % of its initial efficiency after six successive cycles of adsorption–desorption.     

An approximation for kanban controlled assembly systems

An approximation is proposed to evaluate the steady-state performance of kanban controlled two-stage assembly systems. The development of the approximation is as follows. The considered continuous-time Markov chain is aggregated keeping the model exact, and this aggregate model is approximated replacing some state-dependent transition rates with constant rates. The approximate aggregate model is, then, decomposed into submodels and a product-form steady-state distribution is obtained for each submodel. Finally, the submodels are combined in such a way that the size of the problem becomes independent of the number of kanbans. This leads to the computational advantage in solving the combined model using numerical matrix-geometric solution algorithms. Numerical comparisons of the combined model with simulation, exact model, approximate aggregate model and an approximation in the literature show that the proposed approximation performs well in terms of accuracy and computational burden.     

The stochastic transportation problem with single sourcing

We propose a branch-and-price algorithm for solving a class of stochastic transportation problems with single-sourcing constraints. Our approach allows for general demand distributions, nonlinear cost structures, and capacity expansion opportunities. The pricing problem is a knapsack problem with variable item sizes and concave costs that is interesting in its own right. We perform an extensive set of computational experiments illustrating the efficacy of our approach. In addition, we study the cost of the single-sourcing constraints.     

Hepatic nodules in liver transplantation candidates: MR imaging and underlying hepatic disease

OBJECTIVE: To assess by MR imaging the frequency of hepatic nodules in patients waiting on the liver transplant list and to determine whether certain underlying hepatic diseases were more often associated with the development of such hepatic nodules. MATERIAL AND METHODS: We reviewed the MR and clinical records in all patients seen by the liver transplant service at our center since its inception in January 1998 until September 2002. A total of 371 patients (207 men and 164 women, age range 18-68 years, mean 45 years) were included in the study. The presence of hepatic nodules, size, number and underlying hepatic diseases were determined in all patients. Magnetic resonance imaging was performed on a 1.5-T MR imager using T1-weighted, T2-weighted and multi-phase gadolinium-enhanced sequences. Odds ratio (OR) and 95% confidence intervals (CIs) were computed to evaluate the association between the underlying hepatic disease and the development of hepatic nodule. RESULTS: Among 371 liver transplantation candidates, the most common underlying hepatic disease was hepatitis C virus (HCV) infection, either alone (n=93; 25%) or associated with other hepatic diseases (n=40; 10.8%). Of all patients, 33 (8.9%) had regenerative nodules (RNs), 40 (10.7%) dysplastic nodules (DNs) and 57 (15.3%) hepatocellular carcinomas (HCCs). Hepatocellular carcinoma was observed in 35.3% of patients with HCV infection and alcohol abuse combined, 24.5% with cryptogenic cirrhosis, 25% with hemochromatosis and 19% with alcohol abuse. Patients who had either DNs or HCC were 2.5 times more likely to have either alcohol abuse or HCV, alone or combined, as the substrate of their liver disease (OR 2.54, 95% CI 1.56-4.13). Our data suggest a supra-additive interaction between HCV infection and ethanol in their association with MR imaging detected lesions. CONCLUSION: Patients with cryptogenic cirrhosis, alcohol abuse, HCV infection (alone or combined) and hemochromatosis had the greatest likelihood of having HCC, with the combination of HCV infection and alcohol abuse having the highest of all.