Tin(IV) Schiff base complexes: Synthesis, thermodynamic and anti bacterial investigation, experimental and theoretical studies

A series of five coordinated diorganotin(IV) unsymmetrical Schiff base complexes have been synthesized. The structure determination and characterization of these complexes were made on the basis of UV-Vis, IR, (1H and 119Sn) NMR spectroscopy as well as elemental analysis. The binding site of the ligand was identified by IR spectroscopic measurement. Computational analyses at the level of DFT were performed to study its electronic and molecular structures. The molecular geometry, infrared vibrational frequencies, HOMO-LUMO energy gap, dipole moment, Mulliken charges, HF energies were calculated. The theoretical results were consistent with the experimental data reported. The Schiff base ligands and synthesized tin(IV) complexes were screened for their in vitro growth inhibiting activity against different strains of bacteria. Results indicated that the complexes exhibited good antibacterial activities than the ligands. Also the thermodynamic formation constants of the Schiff bases as donors with Me2SnCl2 as an acceptor were measured using UV-Vis spectrophotometric titration for 1:1 complex formation at constant ionic strength (I = 0.1 M NaClO4) and at 25 ºC.               KEY WORDS: Tin(IV) complexes, Thermodynamic parameter, Biological activity, Computational analyses Bull. Chem. Soc. Ethiop. 2019, 33(1), 77-90DOI: https://dx.doi.org/10.4314/bcse.v33i1.8            

Damage detection in concrete gravity dams using signal processing algorithms based on earthquake vibrations

In structural engineering, damage detection in concrete gravity dams (CGDS) is a practical problem. Dam destruction can have severe financial consequences and may even lead to fatalities. Therefore, structural health monitoring in advance is crucial. In this regard, a well-known CGD, namely the Pine Flat Dam, has been chosen for the Finite Element Modeling. In this paper, damage is induced in the dam neck through elasticity modulus reduction by 40 % and 80 %. In addition, after applying Northridge earthquake, the acceleration in structure nodes for intact and damaged cases are recorded in vector formats. Using various methods, such as Discrete-time Fourier Transform (DTFT), Wavelet transform and Wiener transform, the differences between these two signals are investigated. The standard deviation (S.D.) of variations is chosen as the performance metric and is applied to the signal amplitude between intact and damage observations/signals. The reason why several signal processing algorithms are used is finding an approach which shows more clearly the differences caused by the destruction. This is evaluated via S.D. values for different algorithms. The results confirm the superiority of DTFT over other given algorithms. DTFT has a negligible outperformance (approximately zero dB) with respect to the Wavelet transform in both the crest and the lower nodes of the dam. This rate for DTFT and Wavelet is 10dB higher than that of Wiener and 35 dB in comparison with the simple amplitude difference. Moreover, the detection thresholds for the given methods are compared, and it is verified that the DTFT and Wavelet indicate the best performance

Formation constants and thermodynamic parameters of bivalent Co, Ni, Cu and Zn complexes with Schiff base ligand: Experimental and DFT calculations

Formation constant (Kf) values of Schiff base ligand, L = methyl-2-{[1-methyl-2-(aceton)ethylidynenitrilo]ethyl}amino-1-cyclopentenedithiocarboxylate, with Co(II), Ni(II), Cu(II) and Zn(II) ions has been determined spectrophotometrically for 1:1 complex formation at constant ionic strength 0.01 M (NaClO4), and at various temperatures in DMF solvent. Thermodynamic studies of the complexes have been carried out and their stability were found in the order CoL > CuL > NiL > ZnL. The enthalpy, entropy and Gibbs free energy changes of the complexation reaction have been evaluated from the temperature dependence of the formation constant. Our experimental results revealed that the complexation process is spontaneous, exothermic and entropically unfavorable. Also, B3LYP/(LANL2DZ and 6-311G٭٭) level density functional theory is applied on the structure and stability of Schiff base ligand and their complexes. HOMO-LUMO and binding energies were calculated to obtained stability of the complexes. The theoretical results are compared with experimental data

Effect of hope therapy on the hope of diabetic patients

Hope is the most important factor in diabetic patients' life. The level of hope may be changing among these individuals as a result of chronic nature of diabetes and its complications. When the level of hope increases among these patients, they can resist against physical and psychological complications of diabetes more, accept the treatment better, enjoy life more, and adapt with their situations more efficiently. This study aimed to define the efficacy of hope therapy on hope among diabetic patients. This was a quasi-experimental study conducted on 38 diabetic patients referring to Sedigheh Tahereh Research and Treatment Center affiliated to Isfahan University of Medical Sciences in Iran in 2012. The subjects were selected based on the goals and inclusion criteria of the study and then were randomly assigned to study and control groups. Herth Hope Index (HHI) was completed by both groups before, after, and 1 month after intervention. In the study group, 120-min sessions of hope therapy were held twice a week for 4 weeks. Descriptive and inferential statistical tests were adopted to analyze the data through SPSS version 12. Comparison of the results showed that hope therapy significantly increased hope in diabetic patients after intervention in the study group compared to control (P < 0.001). The results showed that hope therapy increased hope among diabetic patients. This method is suggested to be conducted for diabetic patients. Effect of hope therapy on the hope of diabetic patients (PDF Download Available). Available from: https://www.researchgate.net/publication/272842885_Effect_of_hope_therapy_on_the_hope_of_diabetic_patients [accessed Oct 28 2017]

Synthesis, physical characterization, antibacterial activity and thermodynamic studies of five coodrdinate cobalt(III) Schiff base complexes

Some five-coordinated cobalt(III) complexes were synthesized and characterized using elemental analysis, 1H NMR and IR spectra. The formation constants and the thermodynamic parameters were measured spectrophotometrically for the 1:1 adduct formation of [Co(Chel)(PBu3)]ClO4.H2O where Chel = cd3OMesalen, cd4OMesalen, cd5OMesalen: methyl-2-{[1-methyl-2-(2-hydroxy-3-, 4-, 5-methoxyphenyl)methylidynen-itrilo]ethyl}amino-1-cyclopentene-dithiocarboxylate, as acceptors, with some linear and cyclic amines as donors, in different solvents at constant ionic strength (I = 0.1 M NaClO4), and at various temperatures (T = 283-313 K). The results revealed that the formation constants of the Co(III) Schiff base complexes toward a given amines donor are as follow: [Co(cd4OMesalMeen)(PBu3)]+ > [Co(cd3OMesalMeen)(PBu3)]+ > [Co(cd5OMesalMeen)(PBu3)]+. The trend of the formation constants of the donors (amines) toward a given cobalt(III) complex is as follow: Im > 4-MeIm > BzIm and n-butylamine > sec-butylamine > tert-butylamine. Also the effect of the solvents on the formation constants of a given cobalt(III) Schiff base complex toward a given donor are as follow: CH3CN > DMF > EtOH. The ligands and their cobalt complexes have been screened for their antibacterial activities. All the free Schiff base ligands exhibit higher antibacterial activity than the cobalt(III) complexes

The effect of earthworm (Eisenia foetida) meal with vermi-humus on growth performance, hematology, immunity, intestinal microbiota, carcass characteristics, and meat quality of broiler chickens

The present investigation was aimed to evaluate the effect of varied amount of earthworm meal (EW) and vermihumus (VH) on the growth performance of broiler chickens. Three hundred 1-d-old broiler chickens were assigned to 5 starter treatments with 5 pens per treatment, and 12 broiler chickens per pen in a completely randomized design from d 0–14 of the study. Dietary treatments were [per kilogram dry matter (DM)]: control (0 g EW and 0 g VH/kg of DM), and the diets containing 10 g VH/kg of DM supplemented with 0, 10, 20, or 30 g EW/kg of DM. At the end of the study (d 42), one representative broiler chicken per pen, close to the average body weight, was selected for blood sampling using a sterile needle and heparinized vacuum tube. The outcomes of the study depicted the greater overall feed intake value in broiler chicken fed the control diet than those fed the diets containing VH or EW or both, and it decreased linearly and quadratically (P<0.05) as the amount of EW supplementation increased. The average weight gain for the chickens was numerically increased as supplementation of EW was increased (linear, =0.3; quadratic P=0.4). On the other hand, overall feed conversation ratio was slightly greater (P=0.02) in broiler chickens fed the control diet, and it decreased linearly (P=0.03) as dietary EW supplementation increased. Additionally, the serum total protein, albumin, Ca, and P concentrations were lower in broiler chickens fed the control diet, and those variables increased linearly (P<0.05) as dietary EW increased. In like manner, humoral immune response (except heterophil/lymphocyte ratio) and relative weights of immune organs were lower in broiler chickens fed the control diet. Remarkable differences were observed between carcass and ileum characteristics of broiler chickens under treatments. Varied concentrations of EW showed increased total counts of lactic acid bacteria (linear, P<0.05; quadratic, P=0.3) and reduced population of pathogenic intestinal microbiota (linear, P0.05). Similarly, the meat quality of broiler chicken was markedly affected linearly (P<0.05) by the supplementation of increased dietary EW. Briefly, diets containing 30 g EW/kg of DM can positively affect the growth performance of broiler chickens and produce meat with better characteristics

PARTICLES SIZE DISTRIBUTION EFFECT ON 3D PACKING OF NANOPARTICLES INTO A BOUNDED REGION

Abstract In this paper, the effects of two different Particle Size Distributions (PSD) on packing behavior of ideal rigid spherical nanoparticles using a novel packing model based on parallel algorithms have been reported. A mersenne twister algorithm was used to generate pseudorandom numbers for the particles initial coordinates. Also, for this purpose a nanosized tetragonal confined container with a square floor (300 * 300 nm) were used in this work. The Andreasen and the Lognormal PSDs were chosen to investigate the packing behavior in a 3D bounded region. The effects of particle numbers on packing behavior of these two PSDs have been investigated. Also the reproducibility and the distribution of packing factor of these PSDs were compared. Keyword

Prevalence of mechanical dyssynchrony in heart failure patients with different QRS durations

Background: Cardiac resynchronization therapy (CRT) has emerged as an established therapy for congestive heart failure. However, up to 30 of patients fail to respond to CRT despite prolonged QRS. Objectives: This study aimed at defining the prevalence of interventricular and intraventricular dyssynchrony in heart failure patients with different QRS durations. Methods: A total of 123 consecutive patients with severe heart failure (LVEF < 35 and NYHA class III-IV) were prospectively evaluated using 12-lead electrocardiogram and complete echocardiographic examination including tissue Doppler imaging. Results: According to the QRS duration, 56 patients had a QRS duration �120 ms (Group 1), 33 patients had a QRS duration between 120 and 150 ms (Group 2), and 34 patients had a QRS duration �150 ms (Group 3). Intraventricular dyssynchrony was present in 36 of Group 1 patients, in 58 of Group 2 patients, and in 79 of Group 3 patients (P < 0.000). Linear regression demonstrated a weak relation between QRS and intraventricular dyssynchrony. A greater proportion of patients with interventricular dyssynchrony was observed in Group 3 or Group 2 compared to patients with normal QRS duration (32 in Group 1 vs. 51.5 in Group 2 vs. 76.5 in Group 3, P < 0.000). Linear regression demonstrated a significant relation between QRS duration and interventricular mechanical delay. Conclusions: Although both interventricular and intraventricular dyssynchrony increased with the increasing QRS duration, the correlation between intraventricular mechanical and electrical dyssynchrony was weak. The lack of intraventricular dyssynchrony in a fraction of patients with standard CRT indication by QRS duration may provide us insight into the nonresponders rates. © 2007, The Authors