Theoretical investigation on the mechanism and kinetics of the OH•‒initiated atmospheric degradation of p-chloroaniline: Addition of ∑g-3O2 and isomerization of peroxy radicals.

Atmospheric oxidation of the p-chloroaniline-OH• adduct [C6H4ClNH2-OH]• (AD-C2) by ∑g-3O2 and internal isomerization processes of peroxy radical [C6H4ClNH2-OH]•-O2 are theoretically investigated at the M06-2X/aug-cc-pVTZ and CBS-QB3//M06-2X/aug-cc-pVTZ level of theories. Potential energy surfaces (PESs) for the most efficient pathways indicated that the oxidation process begins via the complexation of individual reactants in syn mode forming PRCy-iOO-syn (y = 2,5) in an exothermic and endogenic step. The syn mode addition is favored over the anti one due to the formation of internal hydrogen bond between the hydroxyl and peroxy groups. Formation of new C5-OO bond in PRCy-iOO-syn complex is an unimolecular process which is exothermic and exoergic. This pathway is predominated over other internal conversions due to the presence of stronger intramolecular hydrogen bond. Cyclization of the produced [C6H4ClNH2-OH]•-O2 peroxy radical AD-C2-5OO-syn into the bicyclic peroxy radical AD-C2-5,6OO-syn is the last step which is strongly endothermic and endogenic. The rate coefficients are calculated by means of the RRKM theory over the temperature range 250-350 K and at a pressure range of 0.1 bar to the high-pressure limit. The RRKM rate coefficients at the M06-2X/aug-cc-pVTZ level for the first bimolecular and last unimolecular steps are in order of 10-16 cm3 molecule-1 s-1 and 10-7 s-1, respectively, while the obtained rate coefficients at the CBS-QB3//M06-2X/aug-cc-pVTZ are overestimated about two order of magnitude.

Theoretical investigation on the mechanism and kinetics of the OH•‒initiated atmospheric degradation of p-chloroaniline via OH•‒addition and hydrogen abstraction pathways.

Atmospheric oxidative degradation of p-chloroaniline (PCA) initiated by OH• has been studied theoretically at the M06-2X/aug-cc-pVTZ and CBS-QB3//M06-2X/aug-cc-pVTZ levels, coupled with kinetic calculations using the RRKM/ZCT method over the temperature range of 250-350 K. The calculations exhibit that the OH• addition and hydrogen atom abstraction pathways are thermodynamically favorable. RRKM results revealed that the atmospheric oxidation of PCA is dominated by OH addition to the C1 and C2 atoms and hydrogen atom abstraction from amino group. The individual and overall rate coefficients of PCA reaction triggered by OH• at 1 bar are negatively linear dependent on the temperature and their values are consistent with the experimental data. RRKM calculations also show that the transition state theory approximation for estimation of rate coefficients at ambient pressure breaks down and very high pressures are essential to be valid. The atmospheric life-time at the benchmark CBS-QB3 level is smaller than 2 days.

Sulfonated calixarene modified Poly(methyl methacrylate) nanoparticles:A promising adsorbent for Removal of Vanadium Ions from aqueous media.

The poly (methyl methacrylate) (PMMA)-based nanoparticle was synthesized by surfactant-free emulsion polymerization method and then post modified with Calixarene using (3-Aminopropyl)triethoxysilane organo-silane as a linker after OH-treatment. The prepared structure was applied for efficient adsorption of Vanadium ions in the aqueous solution after characterization by FT-IR, SEM, TEM, DLS, and EDX. Additional investigations discovered that the prepared adsorbent has a good capacity to adsorb vanadium ions. The effect of key experimental factors was studied to find the optimal point of adsorbent efficiency including the initial concentration of analyte, sorbent dosage, pH of the solution, contact time, and type/quantity of the eluents. It was specified, the maximum adsorption capacity for the synthesized nanoparticles was obtained about 322 mg g-1. The adsorption mechanism was revealed that the model of Langmuir isotherm well-matched compared to the others due to the calculated equilibrium data. Besides, the kinetics of the adsorption process was fitted with pseudo-second-order. Eventually, the prepared adsorbent was successfully applied in vanadium adsorption from real water media.

Interacción de SWCNTs con anticancerígenos de dopamina y serotonina a través de métodos de QM/MM: Un enfoque de administración de medicamentos / SWCNTs Interaction with Dopamine and Serotonin Anticancer Through QM/MM Methods: A Drug Delivery Approaches

Objetivo: La dopamina y la serotonina son los dos importantes transmisores biológicos que tienen actividades hormonales y son responsables de la felicidad y el bienestar. El objetivo de este artículo fue estudiar teóricamente las características estructurales de la dopamina y la serotonina en el complejo de nanotubos de carbono de pared simple como neurotransmisor. Material y métodos: Se estudió la estructura de la unión de dopamina y serotonina con SWCNT con cuatro diámetros diferentes (7.0, 7.5, 7.7, 10.0 nm) utilizando mecánica molecular (MM) y mecánica cuántica (QM). Las energías notables, incluida la energía potencial, la energía total y la energía cinética en el tiempo de simulación en pasos de 10 ns en dos temperaturas (298, 310 grados kelvin), fueron investigadas por el método de Monte Carlo con fuerza opls archivada. También se han cumplido los datos del tensor de blindaje de RMN según el nivel de teoría B3LYP con 6-31 G (d) como conjunto de base y método semi empírico. Resultados: Se realizaron cálculos teóricos para estudiar los datos de desplazamiento químico de RMN, incluido el tensor de blindaje magnético (σ, ppm), la asimetría de blindaje (η), la anisotropía de blindaje magnético (σaniso), la isotropía de blindaje magnético (σiso), la desviación de un tensor (Κ) y anisotropía de desplazamiento químico (Δσ) y span (Ω) en varios ángulos de rotación alrededor de una rotación específica, propiedades físicas y químicas de los núcleos atómicos. Se revelaron cálculos semi empíricos como energía total, energía de enlace, energía atómica aislada, energía electrónica, interacción núcleo-núcleo y calor de formación en Am1. Conclusión: En el método Monte Carlo se deduce que nuestros dos fármacos específicos y su nanotubo de pequeño diámetro son los más estables que los demás. El diámetro más grande lleva la estabilidad de la combinación a un valor más bajo.

Objetive:Dopamine and Serotonin are the two important biological transmitters that have hormonal activities and responsible for happiness and felling well. The aim of this article was to study theoretically the structure features of Dopamine and Serotonin in the complex of single-walled carbon nanotube as a neurotransmitter. The structure of Dopamine and Serotonin binding with Material and Methods:SWCNTwith four different diameters (7.0,7.5,7.7,10.0 nm) was studied by using molecular mechanic (MM) and quantum mechanic (QM). The remarkable energies including potential energy, total energy and kinetic energy in time of simulation 10 ns steps in two temperatures (298, 310 kelvin degree) were investigated by Monte Carlo method with opls force filed. NMR shielding tensor data by B3LYPlevel of theory with 6-31 G(d) as a basis set and semi empirical method have been also fulfilled.Results: Theoretical computations were performed to study NMR chemical shift data including magnetic shielding tensor (σ, ppm), shielding asymmetry (η), magnetic shielding anisotropy (σaniso), magnetic shielding isotropy (σiso) , skew of a tensor (Κ) and chemical shift anisotropy (Δσ) and span (Ω) at various rotation angles around a specific rotation, physical and chemical properties of atomic nuclei. Semi empirical calculations such as total energy, binding energy, isolated atomic energy, electronic energy, core­core interaction and heat of formation in AM1 were revealed. It is figured out Conclusion:in Monte Carlo method our two specific drug and its nanotube with small diameter are the most stable one than the others. The larger diameter leads the combination stability into lower value

Effect of chrysin omega-3 and 6 fatty acid esters on mushroom tyrosinase activity, stability, and structure.

The estreification of chrysin with α-Linolenic acid (complex I) and linoleic acid (complex II) poly unsaturated fatty acids resulted to design of new mushroom tyrosinase (MT) inhibitors. Thermodynamic parameters of enzymes, including the melting point (Tm ) and ∆G values, were obtained from thermal and chemical denaturation curves. Complexes I and II showed a competitive inhibitory effect on MT with Ki values of 0.45 and 0.29 mM, respectively. The Tm values were calculated as 328.6, 322.4, and 318 K and the ∆G values as 62.8, 52.9, and 47.1 KJ mol-1 for the enzyme alone and its interaction with complexes I and II, respectively. Intrinsic and extrinsic fluorescence techniques showed structural instability of the enzyme in concomitance with a decrease in the regular secondary structure acquired using CD spectrometry. This data clearly prove that the new derivatives show a stronger inhibitory effect than the separate compounds. Molecular docking analysis showed that the best possible interaction condition was achieved for chrysin with n-6. PRACTICAL APPLICATIONS: MT is a suitable model in medicine for the investigation of melanogenesis, skin disorders, and hyperpigmentation because of its accessibility and close structural similarity to mammalian tyrosinase. In recent years, the designing of tyrosinase inhibitors from natural substances for prevention of hyperpigmentation in medicine, skin cosmetics, and undesired browning in agriculture and food industry has risen sharply. Many of the pharmaceutical products based on the use of flavonoids and poly unsaturated acids as natural compounds or on their semi-synthetic derivatives have been interested for investigations because of their usefulness in many pathological conditions such as inflammation, cancer, and skin disorders. The limitation of the flavonoids applications are low bioavailability, permeability, and solubility for the cells. In this study, conjugation of chrysin with n-3 and n-6 fatty acids resulted in a stronger inhibitors of MT with a synergic inhibitory effect on its activity.

Capability of parasulfonato calix[6]arene, as an anion dopant, and organic solvents in enhancing the sensitivity and loading of glucose oxidase (GOx) on polypyrrole film in a biosensor: a comparative study.

In this study, the effects of two solvents (acetonitrile and water) and an anion dopant (para sulfonato calix[6]arene ((C[6]S)(-6))), on the manufacturing and properties of a polypyrrole (Ppy)-based, glucose oxidase amperometric biosensor were studied. Pyrrole was polymerized using galvanostatic mode in two different solvents, and the effect of (C[6]S)(-6) was studied in aqueous solution. The morphology of the obtained polypyrrole films was studied by scanning electron microscopy (SEM). Glucose oxidase (GOx) was adsorbed on the Ppy films via cross-linking method. Then the amperometric responses of the Pt/Ppy/GOx electrodes were measured using the amperometric method at the potential of 0.7 V in steps of adding a glucose solution to a potassium phosphate buffer. We found that acetonitrile and (C[6]S)(-6) increase the sensitivity of the enzyme electrode up to 79.30 µA M(-1)cm(-2) in comparison with 31.60 µA M(-1)cm(-2) for the electrode synthesized in calixarene free aqueous solvent. Also (C[6]S)(-6) has the main role in preventing leaching the enzyme from the electrode. This fact increases loading of the enzyme and stability of the biosensor. So that the steady state current density of the aforementioned electrode increases linearly with increasing glucose concentration up to 190 mM. Whereas the linearity was observed up to 61 mM and 80 mM for the electrodes made using calixarene free acetonitrile and aqueous solutions, respectively.

Interaction modes and absolute affinities of α-amino acids for Mn2+: a comprehensive picture.

Manganese is involved as a cofactor in the activation of numerous enzymes as well as the oxygen-evolving complex of photosystem II. Full understanding of the role played by the Mn(2+) ion requires detailed knowledge of the interaction modes and energies of manganese with its various environments, a knowledge that is far from complete. To bring detailed insight into the local interactions of Mn in metallopeptides and proteins, theoretical studies employing first-principles quantum mechanical calculations are carried out on [Mn-amino acid](2+) complexes involving all 20 natural α-amino acids (AAs). Detailed investigation of [Mn-serine](2+), [Mn-cysteine](2+), [Mn-phenylalanine](2+), [Mn-tyrosine](2+), and [Mn-tryptophan](2+) indicates that with an electron-rich side chain, the most stable species involves interaction of Mn(2+) with carbonyl oxygen, amino nitrogen, and an electron-rich section of the side chain of the AA in its canonical form. This is in sharp contrast with aliphatic side chains for which a salt bridge is formed. For aromatic AAs, complexation to manganese leads to partial oxidation as well as aromaticity reduction. Despite multisite binding, AAs do not generate strong enough ligand fields to switch the metal to a low- or even intermediate-spin ground state. The affinities of Mn(2+) for all AAs are reported at the B3LYP and CCSD(T) levels of theory, thereby providing the first complete series of affinities for a divalent metal ion. The trends are compared with those of other cations for which affinities of all AAs have been previously obtained.

Molecular dynamic study of human prion protein upon D178N mutation: new perspective to H-bonds, salt bridges and the critical amino acids.

The molecular dynamics simulation method was used to investigate the structural details for human prion protein (PrPN) and its D178N mutant (PrPM). Root-mean-square fluctuations (RMSFs) and the root-mean-square deviations (RMSDs) showed an increase in the flexibility and high dynamic plasticity of PrPM. Average Total energy for PrPM and PrPN sequentially was -2.975 x105 (kJmol-1) and -3.193 x 105 (kJmol-1). The results showed conformational rearrangement susceptibility for PrPM. For PrPM, highly surface-exposed Glu196 and Arg136 caused hydrogen bond weakening and electrostatic interactions changes in salt bridges. Hydrogen bond weakening under mutation can be mentioned as the leader of conformational changes and disease-related conversions. Contrary to some reports, the contributions of electrostatic interactions of Glu146-Arg208 and Arg156-Glu196 salt bridges for PrPN is less than of these interactions for PrPM. These interactions can pave the way to conformational changes in PrPM. The results showed that the role of the hydrogen bonds in the stability of human prion protein is more important than these salt bridges. The calculation of the solvent accessible surface area showed that the conformational plasticity in PrPM is mainly due to Asn residues that were solvent exposed. Conformational changes in the specific amino acids can affect metal-ion occupancy and function. The secondary structure has also showed that the structural transition arose from D178N mutation and occurs in specific residues. Our studies support the large scale effects of electrostatic forces at key position 178 of prion. As a result, the conformational rearrangements happen by eliminating only a single negative charge because of the mutation induced global forces in the prion structure. These rearrangements can be considered as a molecular switch, which triggers the initial stages of the conformational transition.

Comparison of 4-chloro-2-nitrophenol adsorption on single-walled and multi-walled carbon nanotubes.

The adsorption characteristics of 4-chloro-2-nitrophenol (4C2NP) onto single-walled and multi-walled carbon nanotubes (SWCNTs and MWCNTs) from aqueous solution were investigated with respect to the changes in the contact time, pH of solution, carbon nanotubes dosage and initial 4C2NP concentration. Experimental results showed that the adsorption efficiency of 4C2NP by carbon nanotubes (both of SWCNTs and MWCNTs) increased with increasing the initial 4C2NP concentration. The maximum adsorption took place in the pH range of 2-6. The linear correlation coefficients of different isotherm models were obtained. Results revealed that the Langmuir isotherm fitted the experimental data better than the others and based on the Langmuir model equation, maximum adsorption capacity of 4C2NP onto SWCNTs and MWCNTs were 1.44 and 4.42 mg/g, respectively. The observed changes in the standard Gibbs free energy, standard enthalpy and standard entropy showed that the adsorption of 4C2NP onto SWCNTs and MWCNTs is spontaneous and exothermic in the temperature range of 298-328 K.

Optically active: microwave-assisted synthesis and characterization of L-lysine-derived poly (amide-imide)s.

L-lysine hydrochloride was transformed to ethyl L-lysine dihydrochloride. This salt was reacted with trimellitic anhydride to yield the corresponding diacid (1). Microwave-assisted polycondensation results a series of novel Poly (amide-imide)s (PAI (a-i)). These polymers have inherent viscosities in the range of 0.23-0.66 dl g(-1), display optical activity from +8.02 to +15.11 (as there is no obvious regioselectivity between alpha and epsilon amino groups of the chiral diacid during the polymerization step then random orientation of diacid moieties along the polymer backbone can be predicted and the concept of "tacticity" cannot be addressed in this research), and are readily soluble in polar aprotic solvents. They start to decompose (T (10%)) above 362°C and display glass-transition temperatures at 119-153°C. All of the above polymers were fully characterized by UV, FT-IR and (1)H NMR spectroscopy, elemental analysis, thermogravimetric analyses, DSC, inherent viscosity measurement and specific rotation.

Effects of 5-year interventions on cardiovascular risk factors of factories and offies employees of isfahan and najafabad: worksite intervention project-isfahan healthy heart program.

BACKGROUND: Effects of 5-year interventions of Worksite Intervention Project from Isfahan Healthy Heart Program on cardiovascular risk factors of factories and offices employees were studied in Isfahan and Najafabad (intervention area) compared to Arak (control area). METHODS: We had especial interventions for nutrition, physical activity and smoking as well as hypertension and obesity screening systems in all offices and factories, and other risk factors screening systems whenever possible. Before and after the interventions, questionnaires containing demographic and other required data were completed for the two populations; height, weight and blood pressure (BP) were measured and a fasting and 2h blood sample was taken for the measurement of blood sugar (BS) and lipid levels. RESULTS: The prevalence of hypercholesterolemia, hypertriglyceridemia and central obesity decreased, but low HDL increased in office staff (P < 0.01). Waist circumference, HDL and total cholesterol mean values decreased, and diastolic BP and fasting and 2h BS increased among the intervention group. In factory workers, the prevalence of hypertriglyceridemia and central obesity decreased, while low HDL prevalence increased in intervention group (P < 0.001). Mean values of waist circumference, HDL and total cholesterol, and triglyceride decreased significantly (P < 0.001), while diastolic BP and fasting BS increased. CONCLUSION: It seems that Worksite Intervention Project has a protective effect on CVD risk factors in factories and offices employees. So, the modifiable project can be used as an applicable tool for health improvement in worksites which creates tangible changes in employees' lifestyle.

{1,1'-[2,2-Dimethyl-propane-1,3-diylbis(nitrilo-methyl-idyne)]di-2-naphtholato}nickel(II).

In the title Schiff base complex, [Ni(C(27)H(24)N(2)O(2))], the Ni(II) atom shows a slightly distorted square-planar geometry. The dihedral angle between the mean planes of the two aromatic rings is 6.16 (6)°. In the crystal, pairs of inter-molecular weak C-H⋯O hydrogen bonds link neighboring mol-ecules into a chain along the a axis. The crystal structure is further stabilized by two inter-molecular π-π inter-actions with centroid-centroid distances of 3.7252 (13) and 3.8323 (13) Å.

{6,6'-Dieth-oxy-2,2'-[2,2-dimethyl-propane-1,3-diylbis(nitrilo-methyl-idyne)]diphenolato}(2-eth-oxy-6-formyl-phenolato)cobalt(III)-ethanol-water (1/1/1).

The asymmetric unit of the title compound, [Co(C(23)H(28)N(2)O(4))(C(9)H(9)O(3))]·C(2)H(5)OH·H(2)O, comprises one complex mol-ecule, a water mol-ecule of crystallization and an ethanol mol-ecule of crystallization, which is disordered over two positions with a ratio of refined site occupancies of 0.567 (10):0.433 (10). The Co(III) ion is in a slightly distorted octa-hedral geometry involving an N(2)O(2) atom set of the tetra-denate Schiff base ligand and two O atoms of 2-eth-oxy-6-formyl-phenolate. The H atoms of the water mol-ecule act as donors in the formation of bifurcated inter-molecular O-H⋯(O,O) hydrogen bonds with the O atoms of the hydr-oxy and eth-oxy groups with R(1) (2)(5) ring motifs, which may influence the mol-ecular conformation. The crystal structure is further stabilized by inter-molecular O-H⋯O and C-H⋯O inter-actions.

Process evaluation of a community-based program for prevention and control of non-communicable disease in a developing country: The Isfahan Healthy Heart Program, Iran.

BACKGROUND: Cardiovascular diseases are the most common cause of mortality in Iran. A six-year, comprehensive, integrated community-based demonstration study entitled Isfahan Healthy Heart Program (IHHP) conducted in Iran, and it started in 2000. Evaluation and monitoring are integrated parts of this quasi-experimental trial, and consists of process, as well as short and long-term impact evaluations. This paper presents the design of the "process evaluation" for IHHP, and the results pertaining to some interventional strategies that were implemented in workplaces METHODS: The process evaluation addresses the internal validity of IHHP by ascertaining the degree to which the program was implemented as intended. The IHHP process evaluation is a triangulated study conducted for all interventions at their respective venues. All interventional activities are monitored to determine why and how some are successful and sustainable, to identify mechanisms as well as barriers and facilitators of implementation. RESULTS: The results suggest that factory workers and managers are satisfied with the interventions. In the current study, success was mainly shaped by the organizational readiness and timing of the implementation. Integrating most of activities of the project to the existing ongoing activities of public health officers in worksites is suggested to be the most effective means of implementation of the health promoting activities in workplaces. CONCLUSION: The results of our experience may help other developing countries to plan for similar interventions.

The effect of ring size on vibrational spectroscopy and hydrogen bonding properties for the complexes between small ring carbonyl compounds with HF and HCl: theoretical analysis.

The effect of the molecular structure on the properties of C = O...HX (X = F, Cl) bonds was investigated in a set of small cyclic carbonyl compounds, using vibrational spectroscopy and B3LYP/6-311G** calculations. Two main effects were studied: the size of the ring and the inclusion of oxygen atoms in the ring. In these complexes the C = O and H-X participating bonds in the hydrogen-bond are elongated, while others bonds are compressed. The calculated vibrational spectra were interpreted and band assignments were reported. Surface potential energy calculations are carried out with scanning HCl and HF near oxygen atom.

µ-2,3,5,6-Tetra-2-pyridylpyrazine-κN,N,N:κN,N,N-bis-[(methanol-κO)(nitrato-κO,O')(nitrato-κO)cadmium(II)].

The title complex, [Cd(2)(NO(3))(4)(C(24)H(16)N(6))(CH(4)O)(2)], displays a centrosymmetric dinuclear structure, in which the 2,3,5,6-tetra-2-pyridinylpyrazine (tppz) ligand links two Cd ions separated by 7.323 (4) Å. Each Cd(II) center is seven-coordinated by three N-atom donors of tppz in one plane, by two O atoms nearly normal to this plane, and by two O atoms 0.393 (3) and 0.488 (3) Šfrom that plane. The two Cd(II) ions are above and below the plane of the pyrazine ring of the tppz ligand, oriented with respect to the pyridine rings at dihedral angles of 38.01 (3) and 31.90 (3)°. The dihedral angle between the two pyridine rings is 41.11 (3)°. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules.

Solid-phase extraction and spectrophotometric determination of mercury with 6-mercaptopurine in environmental samples.

A highly selective, sensitive and rapid method for the determination of trace amounts of inorganic mercury based on the reaction of Hg (II) with 6-mercaptopurine and the solid phase extraction of the complex on C18 membrane disks was developed. The 6-mercaptopurine selectively reacts with Hg (II) to form a complex in the pH range of 5-8. This complex was preconcentrated by solid phase extraction with C18 disks. An enrichment factor of 100 was achieved. The molar absorptivity of the complex is 0.26 x 10(-6) L. mol(-1) cm(-1) measured at 315 nm. The Beer's law is obeyed in the concentration range of 0.002-0.048 microg mL(-1). The relative standard deviation for eleven-replicated measurement of 0.04 microg mL(-1) is 1.5 %. The detection limit is 0.001 microg mL(-1) in the water samples. The advantage of the method is that the determination of Hg (II) is free from interference of almost all the cations and anions found in environment and wastewater samples. The determination of Hg (II) in water samples of different origins and marine sediment were carried out by the present method and cold vapor atomic absorption spectrometry (CVAAS). Also the method's accuracy was investigated by using SRM 2709. The obtained results by the present procedure were in good agreement with those of the CVAAS and certified value, so that the applicability of the proposed method was confirmed for the real samples.