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Цель исследования. Установить степень влияния наследственных факторов на физико-химические и морфофункциональные особенности эмали зуба как фактора, обуславливающего кариесрезистентность или восприимчивость к кариозному процессу.Методы. Для решения поставленной задачи на зубах, удаленных по показаниям, близнецовой выборки (30 монозиготных и 30 дизиготных пар близнецов) методом электронного парамагнитного резонанса проанализирована степень наследственной и средовой обусловленности физико-химических и структурных свойств эмали интактных и кариозных зубов. Метод электронного парамагнитного резонанса (ЭПР) позволяет получить уникальную информацию о микроскопических и макроскопических свойствах вещества, которую нельзя получить с помощью рентгеноструктурного, спектрального и других анализов.Результаты. Нами выявлено, что концентрация парамагнитных центров, образующихся после облучения, как правило, в 1.5–2 раза выше в эмали кариозных зубов, чем в интактных. Величина К, характеризующая кариесвосприимчивость, наиболее выражена при сопоставлении концентрации свободных радикалов в эмали здоровых и кариозных зубов; у резцов на вестибулярной поверхности (1.35), У моляров в пришеечной области (1.97). Как известно, радиационную стойкость твердых тел можно характеризовать концентрацией парамагнитных центров, образованных после облучения. Эта устойчивость, в свою очередь, связана со структурой, химическим составом, прочностью химических связей. Анализ результатов близнецовых исследований показал, что внутрипарные различия в концентрации свободных радикалов F-центра соответствующих участков эмали зубов в монозиготных парах были достоверно ниже (1.6), чем в идентичных участках эмали зубов дизиготных близнецовых пар (7.0). Высокие значения показателя наследуемости (Н=0.81) дают основания сделать заключение о существенном вкладе наследственных факторов на изучаемый показатель.Выводы. Физико-химические и морфологические свойства эмали обуславливают восприимчивость или устойчивость зубов к кариозному поражению и испытывают высокую степень наследственных влияний (Н-0.81, Н-0,95).На основании результатов исследования можно сделать вывод, что структура эмали генетически детерминирована. Это указывает на необходимость индивидуального подхода к проведению профилактических мероприятий с выделением групп риска к кариесу зубов, Aim. To determine the degree of influence of hereditary factors on the physicochemical and morphofunctional features of tooth enamel as a factor determining caries resistance or susceptibility to the carious process.Methods. To solve the problem, the degree of hereditary and environmental conditioning of the physico-chemical and structural properties of the enamel of intact and carious teeth was analyzed using the method of electron paramagnetic resonance on teeth removed by indications of a twin sample (30 monozygotic and 30 dizygotic pairs of twins). The method of electron paramagnetic resonance (EPR) allows one to obtain unique information about microscopic and macroscopic properties of tooth enamel, which cannot be obtained with the help of X-ray diffraction, spectral and other analyzes.Result. We found that the concentration of paramagnetic centers formed after irradiation is generally 1.5-2 times higher in enamel of carious teeth than in intact ones. The value of K, which characterizes caries susceptibility, is most pronounced when comparing the concentration of free radicals in the enamel of intact and carious teeth; incisors on the vestibular surface (1.35), in molars in the cervical region (1.97). As is known, the radiation resistance of solids can be characterized by the concentration of paramagnetic centers formed after irradiation. This stability, in turn, is related to the structure, chemical composition, strength of chemical bonds. Analysis of the results of twin studies showed that the intraparity differences in the concentration of free radicals of the F-center of the corresponding parts of the enamel of teeth in monozygotic pairs were significantly lower (1.6) than in identical sites of dizygotic twin pairs (7.0). High values of the heritability index (H-0.81) give grounds for making a conclusion about the significant contribution of hereditary factors to the indicator under studyConclusions. The physico-chemical and morphological properties of the enamel determine the susceptibility or stability of the teeth to carious lesions and experience a high degree of hereditary influences (H-81, H-0.95). Based on the data obtained, it can be concluded that the structure of the enamel is genetically determined. This indicates the need for an individual approach to the implementation of preventive measures with the allocation of risk groups to tooth decay, Мета дослідження. Встановити ступінь впливу спадкових факторів на фізико-хімічні та морфофункціональні особливості емалі зуба як фактора, що обумовлює резистентність від карієсу або сприйнятливість до каріозної процесу.Методи. Для вирішення поставленого завдання на зубах, видалених за показаннями, близнюкової вибірки (30 монозиготних і 30 дизиготних пар близнюків) методом електронного парамагнітного резонансу проаналізовано ступінь спадкової і середовищної обумовленості фізико-хімічних і структурних властивостей емалі інтактних і каріозних зубів. Метод електронного парамагнітного резонансу (ЕПР) дозволяє отримати унікальну інформацію про мікроскопічні і макроскопічні властивості речовини, яку неможливо одержати за допомогою рентгеноструктурного, спектрального та інших аналізів.Результати. Нами виявлено, що концентрація парамагнітних центрів, що утворюються після опромінення, як правило, в 1.5–2 рази вище в емалі каріозних зубів, ніж в інтактних. Величина К, що характеризує вразливість, найбільш виражена при зіставленні концентрації вільних радикалів в емалі здорових і каріозних зубів; у різців на вестибулярної поверхні (1.35), у молярів в пришийковій ділянці (1.97). Як відомо, радіаційну стійкість твердих тіл можна характеризувати концентрацією парамагнітних центрів, утворених після опромінення. Ця стійкість, в свою чергу, пов'язана зі структурою, хімічним складом, міцністю хімічних зв'язків. Аналіз результатів близнюкових досліджень показав, що відмінності всередині пар в концентрації вільних радикалів F-центру відповідних ділянок емалі зубів у монозиготних парах були достовірно нижче (1.6), ніж в ідентичних ділянках емалі зубів дизиготних близнюкових пар (7.0). Високі значення показника спадковості (Н=0.81) дають підстави зробити висновок про істотний внесок спадкових факторів на досліджуваний показник.Висновки. Фізико-хімічні та морфологічні властивості емалі обумовлюють сприйнятливість або стійкість зубів до каріозного ураження та відчувають високу ступінь спадкових впливів (Н -0.81, Н-0,95). На підставі результатів дослідження можна зробити висновок, що структура емалі генетично детермінована. Це вказує на необхідність індивідуального підходу до проведення профілактичних заходів з виділенням груп ризику до карієсу зубів

We report the structural and biochemical characterization of GLB-33, a putative neuropeptide receptor that is exclusively expressed in the nervous system of the nematode Caenorhabditis elegans. This unique chimeric protein is composed of a 7-transmembrane domain (7TM), GLB-33 7TM, typical of a G-protein-coupled receptor, and of a globin domain (GD), GLB-33 GD. Comprehensive sequence similarity searches in the genome of the parasitic nematode, Ascaris suum, revealed a chimeric protein that is similar to a Phe-Met-Arg-Phe-amide neuropeptide receptor. The three-dimensional structures of the separate domains of both species and of the full-length proteins were modeled. The 7TM domains of both proteins appeared very similar, but the globin domain of the A. suum receptor surprisingly seemed to lack several helices, suggesting a novel truncated globin fold. The globin domain of C. elegans GLB-33, however, was very similar to a genuine myoglobin-type molecule. Spectroscopic analysis of the recombinant GLB-33 GD showed that the heme is pentacoordinate when ferrous and in the hydroxide-ligated form when ferric, even at neutral pH. Flash-photolysis experiments showed overall fast biphasic CO rebinding kinetics. In its ferrous deoxy form, GLB-33 GD is capable of reversibly binding O2 with a very high affinity and of reducing nitrite to nitric oxide faster than other globins. Collectively, these properties suggest that the globin domain of GLB-33 may serve as a highly sensitive oxygen sensor and/or as a nitrite reductase. Both properties are potentially able to modulate the neuropeptide sensitivity of the neuronal transmembrane receptor. ispartof: Journal of Biological Chemistry vol:290 issue:16 pages:10336-10352 ispartof: location:United States status: published

The unique architecture of the active site of Thermobifida fusca truncated hemoglobin (Tf-trHb) and other globins belonging to the same family has stimulated extensive studies aimed at understanding the interplay between iron-bound ligands and distal amino acids. The behavior of the heme-bound hydroxyl, in particular, has generated much interest in view of the relationships between the spin-state equilibrium of the ferric iron atom and hydrogen-bonding capabilities (as either acceptor or donor) of the OH− group itself. The present investigation offers a detailed molecular dynamics and spectroscopic picture of the hydroxyl complexes of the WT protein and a combinatorial set of mutants, in which the distal polar residues, TrpG8, TyrCD1, and TyrB10, have been singly, doubly, or triply replaced by a Phe residue. Each mutant is characterized by a complex interplay of interactions in which the hydroxyl ligand may act both as a H-bond donor or acceptor. The resonance Raman stretching frequencies of the Fe−OH moiety, together with electron paramagnetic resonance spectra and MD simulations on each mutant, have enabled the identification of specific contributions to the unique ligand-inclusive H-bond network typical of this globin family. Fil: Nicoletti, Francesco P.. Universita Degli Studi Di Firenze; Italia Fil: Bustamante, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Droghetti, Enrica. Universita Degli Studi Di Firenze; Italia Fil: Howes, Barry D.. Universita Degli Studi Di Firenze; Italia Fil: Fittipaldi, Maria. Universita Degli Studi Di Firenze; Italia Fil: Bonamore, Alessandra. Universita Di Roma; Italia Fil: Baiocco, Paola. Italian Institute of Technology; Italia Fil: Feis, Alessandro. Universita Degli Studi Di Firenze; Italia Fil: Boffi, Alberto. Universita Di Roma; Italia Fil: Estrin, Dario Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentina Fil: Smulevich, Giulietta. Universita Degli Studi Di Firenze; Italia

This thesis presents a detailed study of paramagnetic defects in hydrogenated amorphous silicon (a-Si:H). The defect states act as recombination centers for excess charge carriers and limit the efficiency of thin-film solar cells based on a-Si:H materials. The defect density drastically increases by light irradiation of the solar cell, which is a well-known degradation effect (Staebler Wronski effect - SWE). This effect is the major limitation of solar cells based on a-Si:H. In order to understand the process which leads to the generation of the defects states, detailed knowledge of the microscopic origin of the defect states is mandatory. In this work, the paramagnetic defects present after deposition (native defects) and after degradation with light (light-induced defects) are investigated with electron paramagnetic resonance (EPR). This technique measures the g-value of the defects and hyperfine interaction with magnetic nuclei in their vicinity and therefore allows mapping out the wave function of the defects. Native defects in a-Si:H are localized coordination defects, which were attributed to threefold-coordinated silicon atoms (dangling bonds). A measurement of the EPR spectrum of native defects at various microwave frequencies (multifrequency EPR) is presented in this work and allows a precise determination of the g-values and the hyperfine interactions. The values obtained by the experiment are compared to theoretical density-functional theory calculations of dangling bonds to test if the microscopic origin of native coordination defects can be ascribed to dangling bonds. Defect states generated by light in the SWE are investigated by EPR measurements at high-field (Q-Band). Due to the increased resolution of these experiments, a new type of light-induced defect state could be observed, which exhibits different g-values and a faster primary-echo decay as compared to native coordination defects. In order to perform these advanced EPR experiments on fully-processed thin- film solar cells, electrically detected magnetic resonance (EDMR) is used with its superior sensitivity. A novel EDMR microwave pulse sequence is presented and tested on µc-Si:H solar cells to detect weak hyperfine interactions., Die vorliegende Arbeit ist eine detaillierte Studie von paramagnetischen Defekten in hydrogenisiertem amorphen Silizium (a-Si:H). Die Defektzustände sind Rekombinationszentren für Überschussladungsträger und limitieren die Effizienz von a-Si:H Solarzellen. Die Defektdichte erhöht sich stark bei Bestrahlung der Solarzelle mit Licht durch einen bekannten Degradationseffekt (Staebler-Wronski Effekt - SWE). Dieser Effekt schränkt das Potential von a-Si:H Solarzellen stark ein. Um den Generationsprozess der Defekte besser zu verstehen ist eine Studie der mikroskopischen Struktur der Defekte unerlässlich. In der vorliegenden Arbeit werden die paramagnetischen Defekte nach der Materialdeposition (native Defekte) und nach Lichtdegradation (lichtinduzierte Defekte) mittels Elektronen-Paramagnetischer Resonanz (EPR) untersucht. Diese Technik misst den g-Wert und die Hyperfeinwechselwirkung magnetischer Nuklide in der Defektumgebung und erlaubt es die Defektwellenfunktion genau zu bestimmen. Native Defekte in a-Si:H sind lokalisierte Koordinationsdefekte, welche dreifach-koordinierten Siliziumatomen zu geordnet wurden ("dangling bonds"). In dieser Arbeit wird eine Messung des EPR Spektrums nativer Defekte bei verschiedenen Mikrowellenfrequenzen präsentiert, welche es erlaubt die g-Werte und Hyperfeinwechselwirkungen präzise zu bestimmen. Die experimentellen Werte wurden mit Dichtefunktionaltheorie Rechnungen von dangling bond Defekten verglichen um zu überprüfen ob die mikroskopische Struktur dieser Defekte tatsächlich dangling bond Defekten zugeordnet werden kann. Lichtinduzierte Defekte des SWE wurden mittels Hochfeld-EPR (Q-Band) untersucht. Durch die erhöhte Auflösung dieser Experimente konnte gezeigt werden, dass lichtinduzierte Defekte andere g-Werte und einen schnelleren Echozerfall als native Koordinationsdefekte aufweisen. Um die entwickelten EPR Techniken auch auf Dünnschichtsolarzellen anzuwenden wurde elektrisch detektierte Magnetresonanz (EDMR) eingesetzt um die Empfindlichkeit zu steigern. Eine neuartige EDMR Mikrowellenpulssequenz wurde entwickelt und getestet an µc-Si:H Solarzellen um schwache Hyperfeinwechselwirkungen auszumessen.

Surfactant free ternary systems formulated with organic solvents such as alpha-pinene or n-hexane, short chain alcohols and water, were used as new reaction media to maximize the catalytic performance of chloroperoxidase from Caldariomyces fumago (CPO) towards the oxidation of hydrophobic compounds including olefins and terpenols. The influence of the composition and the hydration state of the system, the nature of the oxidizing agent as well as substrate availability on the catalytic behavior and stability of the enzyme was investigated, using the chlorination of monochlorodimedone (MCD) and the epoxidation of styrene as model reactions. Based on residual chlorination activity measurements, which were in accordance with differential scanning calorimetry (DSC) findings, it was concluded that in low water systems formulated with alpha-pinene CPO stability is significantly increased compared to other reaction media (up to 65% residual activity after 24 h of incubation at 30 degrees C). Electron paramagnetic resonance (EPR) spectroscopy indicated that in low water content systems the ferric environment of the active site of CPO does not undergo severe modifications. Total turnover numbers (TTN) obtained for the oxidation of various olefins and terpenols in alpha-pinene-based systems, were up to 25,000 which is 2-170 times higher than previously reported values. The results indicate that such ternary systems can be efficiently employed as reaction media leading to highly enhanced stability and increase CPO potential as practical catalyst for oxidation of large amounts of hydrophobic compounds in a single-step biocatalytic process. (c) 2007 Elsevier B.V. All rights reserved. Journal of Molecular Catalysis B-Enzymatic

The interaction of copper(II) and manganese(II) with pipemidic acid, Hpipem, afforded the complexes [Cu(pipem)(2)(H2O)](.)2H(2)O, 1 and [Mn(pipem)(2)(H2O)], 2. The new complexes have been characterised by elemental analyses, infrared, UV-vis and X-band EPR spectroscopy in the temperature range from 4 to 300 K. The monoanion, pipem, exhibits O,O ligation through the carbonyl and carboxylato oxygen atoms. Five coordinate square-pyramid configuration has been proposed for 1 and 2, and the fifth apical position is occupied by a coordinated water molecule. (c) 2005 Elsevier B.V. All rights reserved. Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy

The complexes [VO(pycac)] and [VO(pycbac)] were prepared by the reaction of bis(pentane-2,4-dionato)oxovanadium(IV) with either N-[2-(4-oxopent-2-en-2-ylamino)phenyl]pyridine-2-carboxamide (H-2pycac) or N-[2-(4-phenyloxobut-2-en-2-ylamino)-phenyl]pyridine-2-carboxamide (H-2pycbac) in a methanolic solution. Crystals of [VO(pycac)] crystallized from nitromethane were monoclinic, space group P2(1)/n with a = 7.5938 (1) angstrom, b = 30.161 (1) angstrom, c = 13.6982 (2) angstrom, beta = 86.468 (1)-degrees, Z = 8, and R(w) = 5.39%. Crystallization of [VO(pycac)] from chlorobenzene yielded triclinic crystals with a space group P1BAR and a = 7.8558 (5) angstrom, b = 12.934 (1) angstrom, c = 15.675 (1) angstrom, alpha = 78.594 (2)-degrees, beta = 89.938 (2)-degrees, gamma = 88.097 (2)-degrees, Z = 4, and R(w) = 6.45%. [VO(pycbac)] crystals were monoclinic, space group P2(1)/c with a = 6.5422 (4) angstrom, b = 14.4786 (8) angstrom, c = 19.963 (1) angstrom, beta = 93.461 (2)-degrees, Z = 4, and R(w) = 3.80%. The geometry about vanadium in each structure approximates a square pyramid with an average V=O bond length of 1.595 angstrom with the metal ion 0.669 angstrom above the basal plane. The average V-N (pyridine), V-N(amine), V-N(amide), and V-O bond lengths are 2.100, 2.045, 1.981, and 1.916 angstrom, respectively. The V-N(amide) and V-O bond lengths constitute rare examples of such short V-N and V-O distances that have been reported for oxovanadium(IV) complexes to date. In addition to the synthesis and crystallographic studies, we report the optical, infrared, magnetic, electron paramagnetic resonance, and electrochemical properties of these complexes. This study represents the first systematic study of oxovanadium containing a vanadium-amide bond. Inorg Chem

Metal ion complexes of the double-armed p-tert-butylcalix[4]arene derivative possessing imine functionality linked through salicylyl moiety at the lower rim has been synthesized for the first time and characterized by analytical, spectral and magnetic methods. The 1, 3- di-calix[4]arene-imine conjugate exhibits variable coordination behavior, from tetradentate to hexadentate, depending upon the metal ion to which it is bound, by always acting as di-anionic. While it uses both the ether oxygens of the pendants to coordinate in the case of Fe(III), Co(III) and Ni(II) complexes, it uses only the pendant salicylidene moieties in the case of Cu(II) and Zn(II) complexes. The Zn(II) complex catalysis ester hydrolysis through the formation of Zn(II)-hydroxo species.