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Terms modified by Mo Selected AbstractsNeuronal leucine-rich repeat 6 (XlNLRR-6) is required for late lens and retina development in Xenopus laevisDEVELOPMENTAL DYNAMICS, Issue 4 2006Adam D. Wolfe Abstract Leucine-rich repeat proteins expressed in the developing vertebrate nervous system comprise a complex, multifamily group, and little is known of their developmental function in vivo. We have identified a novel member of this group in Xenopus laevis, XlNLRR-6, and through sequence and phylogenetic analysis, have placed it within a defined family of vertebrate neuronal leucine-rich repeat proteins (NLRR). XlNLRR-6 is expressed in the developing nervous system and tissues of the eye beginning at the neural plate stage, and expression continues throughout embryonic and larval development. Using antisense morpholino oligonucleotide (MO) -mediated knockdown of XlNLRR-6, we demonstrate that this protein is critical for development of the lens, retina, and cornea. Reciprocal transplantation of presumptive lens ectoderm between MO-treated and untreated embryos demonstrate that XlNLRR-6 plays autonomous roles in the development of both the lens and retina. These findings represent the first in vivo functional analysis of an NLRR family protein and establish a role for this protein during late differentiation of tissues in the developing eye. Developmental Dynamics 235:1027,1041, 2006. © 2006 Wiley-Liss, Inc. [source] Synthesis and Reactivity of Oxametallacyclic Niobium Compounds by Using ,,,-Unsaturated Carbonyl Ligands,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2008Rocío A. Arteaga-Müller Abstract Reduction of mono(cyclopentadienyl)niobium complexes [NbCpRCl4] [CpR = C5Me4H (1), C5H4SiMe2Cl (2), C5H4SiMe3 (3)] with Na/Hg in the presence of methyl methacrylate [MMA, CH2=C(Me)C(O)OMe (a)], methyl acrylate [MA, CH2=CHC(O)OMe (b)] and mesityl oxide [MO, CMe2=CHC(O)Me (c)] afforded the corresponding derivatives [NbCpRCl2(LL)] [CpR = C5Me4H, LL = MMA (1a); CpR = C5H4SiMe2Cl, LL = MMA (2a), MA (2b), MO (2c); CpR = C5H4SiMe3, LL = MMA (3a), MA (3b)] in variable yields depending on both the cyclopentadienyl and the ,,,-unsaturated carbonyl compounds. The reactivity of these complexes was studied toward protic and Lewis acids. Addition of triflic acid TfOH (Tf = CF3SO2) to 3b gave the triflate complex [NbCpRCl2{(CH2)2C(O)OMe}(OTf)] [CpR = C5H4SiMe3 (4)]. The Lewis acids E(C6F5)3 (E = B, Al) reacted with complexes 2b and 3b to give the three-membered metallacyclic (or ,2 -enone) compounds [NbCpRCl2{,2 -CH2=CHC(OMe){O·E(C6F5)3}}] [CpR = C5H4SiMe2Cl, E = B (5), Al (6); CpR = C5H4SiMe3, E = B (7), Al (8)], which decomposed to the corresponding adducts MA·E(C6F5)3. The same reaction with the 2a and 3a derivatives only allowed the observation of the corresponding adducts MMA·E(C6F5)3. Complexes 2a,b and 3a,b reacted with CO with elimination of the acrylate compounds, MA and MMA, respectively, to give the carbonylniobium(III) compounds [NbCpRCl2(CO)2]2 [CpR = C5H4SiMe2Cl (9), C5H4SiMe3 (10)]. Analogous reactions with CNAr showed the elimination of the free MA and MMA compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Validation of the deCODE Migraine Questionnaire (DMQ3) for use in genetic studiesEUROPEAN JOURNAL OF NEUROLOGY, Issue 11 2006M. Kirchmann We assessed the reliability of the diagnosis of migraine with aura (MA) and migraine without aura (MO) based on the third edition of the deCODE Migraine Questionnaire (DMQ3) using a physician-conducted interview as an empirical index of validity. Amongst Danish migraine families recruited from specialist practice we selected 200 cases diagnosed according to the International Classification of Headache Disorders 2nd Edition in a validated physician-conducted telephone interview: 50 patients with exclusively MA, 50 with both MA and MO, 50 with exclusively MO and 50 controls. A written copy of the DMQ3 was mailed to the participant. The DMQ3-based diagnosis was compared with the interview-based diagnosis. Overall, the DMQ3 diagnosed migraine (MA, MO or both) with a sensitivity of 99% (109/110), a specificity of 86% (32/37) and a kappa statistic of 0.89. The most reliable subtype of migraine was MA (with or without co-occurring attacks of MO) which was diagnosed with a sensitivity of 92% (71/77), a specificity of 93% (65/70) and a kappa statistic of 0.85. Exclusively MO was diagnosed with a sensitivity of 91% (30/33), a specificity of 93% (106/114) and a kappa statistic of 0.80. Weakest was the diagnosis of both MO and MA which was diagnosed with a sensitivity of 63% (24/38), a specificity of 92% (100/109) and a kappa statistic of 0.57. In conclusion, the DMQ3 is a valid tool for diagnosing patients with migraine for genetic studies. [source] Thermal behaviour of cubic phases rich in 1-monooleoyl- rac -glycerol in the ternary systemFEBS JOURNAL, Issue 1 2003- d -glucoside/water, 1-monooleoyl- rac -glycerol/n -octyl- Using synchrotron X-ray diffraction the thermal behaviour was studied of the cubic phases in the 1-monooleoyl- rac -glycerol (MO)/n -octyl-,- d -glucopyranoside (OG)/2H2O system with 58 or 45 wt % MO concentration and varying OG/2H2O contents. These MO contents correspond to a Pn3m cubic single-phase or a Pn3m cubic phase in excess water on the binary MO/water axis of the ternary phase diagram. The cubic liquid crystalline phases are stable with small fractions of OG, while higher OG concentrations trigger a cubic-to-lamellar phase transition. Moreover, with increasing OG concentration the initial Pn3m structure is completely converted to an Ia3d structure prior to the L, phase being formed. Upon heating this effect is reversed, resulting in an Ia3d -to- Pn3m phase transition. For some samples additional peaks were observed in the diffractograms upon heating, resulting from the metastability notoriously shown by bicontinuous cubic phases. This judgement is supported by the fact that upon cooling these peaks were absent. Remarkably, both the Ia3d and the Pn3m cubic structures could be in equilibrium with excess water in this ternary system. A comparison is made with previous results on n -dodecyl-,- d -maltoside (DM), showing that cubic phases with OG have higher thermal and compositional stability than with DM. [source] The Spectrum of Myositis Ossiticans in HaemophiliaHAEMOPHILIA, Issue 2 2004G. V. Massey Summary., Myositis ossificans (MO) refers to non-neoplastic heterotopic soft tissue ossification that can have several aetiologies. Broadly it can be classified into three categories based on aetiology [1]. MO traumatica, the most common form occurs secondary to acute or chronic trauma. MO can also be associated with neurological disorders and in rare cases is congenital. The latter (progressive MO) is a genetic disorder in which congenital osseous abnormalities are associated with progressive soft tissue calcification. Despite an increased tendency to soft tissue bleeds, MO has been rarely reported in haemophilia. We treated three adolescents with haemophilia and MO of varying degrees of severity and outcome. [source] Inorganic Macroporous Films from Preformed Nanoparticles and Membrane Templates: Synthesis and Investigation of Photocatalytic and Photoelectrochemical Properties,ADVANCED FUNCTIONAL MATERIALS, Issue 10 2003D.G. Shchukin Abstract Colloidal dispersions of titania, zirconia, tin oxide, indium oxide, and ceria have been successfully used to impregnate membrane templates and form the respective metal oxide (MO) porous films. The use of alumina and iron oxide sols in the same procedure, however, resulted in compact structures. By mixing different nanoparticle solutions before impregnation, final inorganic films containing two metal oxides, of variable metal oxide ratios, were obtained. The porous inorganic materials were analyzed in terms of surface area, pore size, film thickness, and crystallinity. The mechanism of nanoparticle infiltration and particle adsorption to the template walls is proposed based on the stability of the inorganic film and a study of the influence of either the sol concentration or washing times on the amount of inorganic substance incorporated in the hybrid material. The photocatalytic decomposition of an organic pollutant, 2-chlorophenol, was demonstrated for the porous titania material along with the structures containing mixtures of titania with zirconia, indium oxide, and tin oxide. A ratio of 9:1 TiO2/MO gave the highest photocatalytic activity, which was higher than the activity of Degussa P25 for the TiO2/In2O3 and TiO2/SnO2 systems under the same conditions. The titania films have also been attached to substrates,glass or indium tin oxide (ITO) surfaces,and the photoelectrochemical properties of the porous film attained. A comparison with a spin-coated titania film (prepared from the same colloidal dispersion) showed that the structured porous inorganic film has two times the photoelectrochemical efficiency as the spin-coated film. [source] Myth and Reality in the Attitude toward Valence-Bond (VB) Theory: Are Its ,Failures' Real?HELVETICA CHIMICA ACTA, Issue 4 2003Sason Shaik According to common wisdom propagated in textbooks and papers, valence-bond (VB) theory fails and makes predictions in contradiction with experiment. Four iconic ,failures' are: a) the wrong prediction of the ground state of the O2 molecule, b) the failure to predict the properties of cyclobutadiene (CBD) viz. those of benzene, c) the failure to predict the aromaticity/anti-aromaticity of molecular ions like C5H and C5H, C3H and C3H, C7H and C7H, etc; and d) the failure to predict that, e.g., CH4 has two different ionization potentials. This paper analyzes the origins of these ,failures' and shows that two of them (stated in a and d) are myths of unclear origins, while the other two originate in misuse of an oversimplified version of VB theory, i.e., simple resonance theory that merely enumerate resonance structures. It is demonstrated that, in each case, a properly used VB theory at a simple and portable level leads to correct predictions, as successful as those made by use of molecular-orbital (MO) theory. This notion of VB ,failure', which is traced back to the VB-MO rivalry, in the early days of quantum chemistry, should now be considered obsolete, unwarranted, and counterproductive. A modern chemist should know that there are two ways of describing electronic structure, which are not two contrasting theories, but rather two representations or two guises of the same reality. Their capabilities and insights into chemical problems are complementary, and the exclusion of any one of them undermines the intellectual heritage of chemistry. [source] Successful amplification of degraded DNA for use with high-throughput SNP genotyping platforms,HUMAN MUTATION, Issue 12 2008Simon Mead Abstract Highly accurate and high-throughput SNP genotyping platforms are increasingly popular but the performance of suboptimal DNA samples remains unclear. The aim of our study was to determine the best platform, amplification technique, and loading concentration to maximize genotype accuracy and call rate using degraded samples. We amplified high-molecular weight genomic DNA samples recently extracted from whole blood and degraded DNA samples extracted from 50-year-old patient sera. Two whole-genome amplification (WGA) methodologies were used: an isothermal multiple displacement amplification method (MDA) and a fragmentation-PCR,based method (GenomePlex® [GPLEX]; Sigma-Aldrich, St. Louis, MO). Duplicate runs were performed on genome-wide dense SNP arrays (Nsp-Mendel; Affymetrix) and custom SNP platforms based on molecular inversion probes (Targeted Genotyping [TG]; Affymetrix) and BeadArray technology (Golden Gate [GG]; Illumina). Miscalls and no-calls on Mendel arrays were correlated with each other, with confidence scores from the Bayesian calling algorithm, and with average probe intensity. Degraded DNA amplified with MDA gave low call rates and concordance across all platforms at standard loading concentrations. The call rate with MDA on GG was improved when a 5,×,concentration of amplified DNA was used. The GPLEX amplification gave high call rate and concordance for degraded DNA at standard and higher loading concentrations on both TG and GG platforms. Based on these analyses, after standard filtering for SNP and sample performance, we were able to achieve a mean call rate of 99.7% and concordance 99.7% using degraded samples amplified by GPLEX on GG technology at 2,×,loading concentration. These findings may be useful for investigators planning case-control association studies with patient samples of suboptimal quality. Hum Mutat 0, 1,7, 2008. © 2008 Wiley-Liss, Inc. [source] Determination of the mutation spectrum of the EXT1/EXT2 genes in British Caucasian patients with multiple osteochondromas, and exclusion of six candidate genes in EXT negative cases,,HUMAN MUTATION, Issue 11 2006Lorne Lonie Abstract We describe here the spectrum and distribution of mutations in the EXT1 and EXT2 genes in the largest reported British Caucasian multiple osteochondromas (MO) population. Furthermore, we report for the first time the screening of the EXT1 and EXT2 promoters, 5,UTRs, and 3,UTRs, and exclude six potential MO candidate genes in individuals without a detectable mutation within the coding region of EXT1 and EXT2. The coding exons of EXT1 and EXT2 were screened in 72 unrelated probands affected with MO. Forty-six different mutations were identified in 56 probands, of which 29 were novel. Mutation in the EXT1 and EXT2 genes each accounted for 50% of the mutations identified. Of the 72 probands, 42 were of British Caucasian descent, which when added to the 41 British Caucasian families previously reported from our total cohort, gave a total of 83 families. This cohort's proportional frequency for EXT1/EXT2 mutation was 53%/47%. We also validated the technique of high-resolution melting analysis in a blind study using 27 unique EXT1 or EXT2 mutations. This technique was found to be sensitive with a detection rate of 100% regarding heterozygote detection for EXT mutation scanning. Furthermore, this technique has a very high throughput and is very cost-effective. © 2006 Wiley-Liss, Inc. [source] Dentine demineralization when subjected to EDTA with or without various wetting agents: a co-site digital optical microscopy studyINTERNATIONAL ENDODONTIC JOURNAL, Issue 4 2008G. De-Deus Abstract Aim, To analyse quantitatively the chelating ability of ethylenediaminetetraacetic acid (EDTA) and three common EDTA-based associations with wetting agents. Methodology, Twelve maxillary human molars were selected, from which 3 mm thick discs were obtained from the cervical third of the root. Following the creation of standardized smear layer co-site microscopy image sequences of the dentine surface submitted to EDTA, EDTA plus 0.1% cetavlon® (Sigma Chemical Co., St Louis, MO, USA), EDTA plus 1.25% sodium lauryl ether sulphate and SmearClearÔ (Sybron Endo, Orange, CA, USA) were obtained after several cumulative demineralization times. Sixteen images were obtained of each dentine sample for each experimental time, at 1000× magnification. An image processing and analysis sequence was used to measure the area of open tubules for each experimental time. Thus, it was possible to follow the demineralization process and quantitatively analyse the effect of the various substances. The Student's t -test was used to assess differences between experimental groups. Results, EDTA solution had the strongest effect at all experimental times whilst the association of EDTA with wetting agents showed a weaker chelating effect and this difference was statistically significant (P < 0.05). Conclusions, (i) The EDTA solution had the strongest effect at all experimental times (P < 0.05); (ii) the association of EDTA with wetting agents did not improve the chelating power of the solution; (iii) co-site optical microscopy represents a powerful approach to compare directly, longitudinally and quantitatively the ability of the chelating solutions. [source] Semen quality in fertile US men in relation to geographical area and pesticide exposureINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 1 2006Shanna H. Swan Summary We conducted the first US study to compare semen quality among study centres using standardized methods and strict quality control. We present data on semen quality in partners of 493 pregnant women recruited through prenatal clinics in four US cities during 1999,2001. Sperm concentration, semen volume and motility were determined at the centres and morphology was assessed at a central laboratory. While between-centre differences in sperm morphology and sample volume were small, sperm concentration and motility were significantly reduced in Columbia, MO (MO) relative to men in New York, NY, Minneapolis, MN and Los Angeles, CA; total number of motile sperm was 113 × 106 in MO and 162, 201 and 196 × 106 in CA, MN and NY respectively. Differences among centres remained significant in multivariate models that controlled for abstinence time, semen analysis time, age, race, smoking, history of sexually transmitted disease and recent fever (all p -values <0.01). We hypothesized that poorer sperm concentration and motility in MO men relative to other centres might be related to agricultural pesticides that are commonly used in the mid-west. We investigated this hypothesis by conducting a nested case,control study within the MO cohort. We selected 25 men in this cohort for whom all semen parameters (concentration, % normal morphology and % motile) were low as cases and an equal number of men for whom all semen parameters were within normal limits as controls. We measured metabolites of eight non-persistent, current-use pesticides in urine samples the men had provided at the time of semen collection. Pesticide metabolite levels were elevated in cases compared with controls for the herbicides alachlor and atrazine, and for the insecticide diazinon (2-isopropoxy-4-methyl-pyrimidinol) (p -values for Wilcoxon rank test = 0.0007, 0.012, and 0.0004 for alachlor, atrazine and diazinon respectively). Men with higher levels of alachlor or diazinon were significantly more likely to be cases than men with low levels [odds ratios (OR) = 30.0, 16.7 for alachlor and diazinon respectively], as were men with atrazine over the limit of detection (OR = 11.3). These associations between current-use pesticides and reduced semen quality suggest that agricultural chemicals may have contributed to the reduced semen quality seen in fertile men from mid-Missouri. [source] Kinetics of propane oxydehydrogenation on metals oxides and metals phosphates catalysts: Evidence of compensation effectsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 3 2006B. Y. Jibril Kinetics of oxidative dehydrogenation of propane has been tested on three groups of catalysts; alumina-supported metal oxides (MO) (where metal is V, Cr, Ni, Zr, Mo, or Ba), alumina-supported rare earth metal oxides (RO) (where metal is Ce, Tb, Dy, Ho, Tm, or Yb), and metal phosphates (MP) (where metal is V, Cr, Mn, Ni, Zr, Mg, Ba, or Ce). They were found to be active and exhibited different selectivities to propylene, ethylene, and COx (CO and CO2). The Arrhenius parameters,apparent pre-exponential factor (lnAapp) and activation energy Eapp),were evaluated. Evidence of compensation effects was established through statistically significant linear relationship between ln Aapp and Eapp. The rates of propane conversions and COx productions on MO and MP showed common compensation line different from that of RO. When the data for rates of production of propylene and ethylene were plotted, the line for the ethylene rate on MO appeared above that of propylene rate, contrary to the observation on MP and RO. An attempt was made to associate the differences in the behaviors of the catalysts with differences in the ensembles of chemisorbed species that form the respective active centers. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 176,183, 2006 [source] Evaporative climate change in the British IslesINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 9 2008Gerald Stanhill Abstract Evaporation measurements made at 16 sites in the British Isles were analysed for evidence of long-term changes. Half of the series were from sites in Ireland measured with Class A evaporation pans between 1963 and 2005 and half in England and Scotland measured with the British Meteorological Office (MO) sunken evaporation tank between 1885 and 1968. Four of the Irish series showed significant linear trends, three of increasing and one of decreasing evaporation. These significant changes ranged between , 0.1 and + 0.1 mm year,1 equivalent to annual changes between , 0.22 and + 0.15%. Five of the UK series showed statistically significant linear trends, three of them decrease and two increase: These ranged in size between , 3.7 and + 2.1 mm year,1, equivalent to annual changes of , 1.05 to + 0.40% of the mean. Curvilinear time trends accounted for twice the amount of inter-annual variation in evaporation as did the linear trends. Differences in sunshine duration (SD), used as a proxy for global radiation, were found to be the major factor explaining spatial as well as temporal changes in evaporation in the British Isles. The pooled Irish data, expressed as normalized anomalies, showed a small and significant linear increase in evaporation over the last 40 years. Similarly parameterized the UK measurements showed no significant trend up till 1968; the one UK series that did extend till 2004 indicated a marked increase during the last 20 years. The long-term changes found in annual evaporation were similar to those in air temperatures both in Ireland and England. The relevance of these findings to the hypothesis of an acceleration in the hydrological cycle is discussed. Copyright © 2007 Royal Meteorological Society [source] Circulation dynamics of Mediterranean precipitation variability 1948,98INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 15 2003A. Dünkeloh Abstract Canonical correlation analysis is used to identify main coupled circulation,rainfall patterns and to relate recent variability and trends of Mediterranean precipitation to large-scale circulation dynamics. Analyses are based on geopotential heights (500 and 1000 hPa levels) for the North Atlantic,European area (National Centers for Environmental Prediction,National Center for Atmospheric Research reanalysis) and on highly resolved (0.5° × 0.5° ) monthly rainfall grids (Climatic Research Unit, Norwich) selected for the Mediterranean area during the 1948,98 period. Combining monthly analyses with similar characteristics to seasonal samples yields winter (October,March), spring (April,May) and summer (June,September) types of coupled variability; a particular autumn type for the whole Mediterranean does not occur on the monthly time scale. Coupled patterns specifically linked to one or two seasons include an east Atlantic jet (EA-Jet) related pattern for summer and a Mediterranean meridional circulation (MMC) pattern for winter and spring. The most important pattern recurring with dynamical adjustments throughout the whole year reflects the seasonal cycle of the Mediterranean oscillation (MO), which is linked (with seasonal dependence) to the Northern Hemisphere teleconnection modes of the Arctic oscillation (AO) and North Atlantic oscillation (NAO). Winter rainfall trends of the recent decades marked by widespread decreases in the Mediterranean area and by opposite conditions in the southeastern part are linked to particular changes over time in several of the associated circulation patterns. Thus, different regional rainfall changes are integrated into an overall interrelation between Mediterranean rainfall patterns and large-scale atmospheric circulation dynamics. Copyright © 2003 Royal Meteorological Society [source] An efficient algorithm for mobile objects localizationINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 3 2008M. Salamah Abstract A new efficient algorithm based on time of arrival to determine the position of a mobile object (MO) in a wireless environment is proposed. Since all operations in our algorithm are simple add and shift operations, it can be easily implemented in the MO's firmware or hardware to reduce the number of instructions and computational cost involved in the localization task. Simulation results show that the proposed algorithm outperforms other algorithms in terms of computational cost and implementation simplicity. Copyright © 2007 John Wiley & Sons, Ltd. [source] Theory of chemical bonds in metalloenzymes.INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2010Abstract Reaction mechanisms of oxygen evolution in native and artificial photosynthesis II (PSII) systems have been investigated on the theoretical grounds, together with experimental results. First of all, our previous broken-symmetry (BS) molecular orbitals (MO) calculations are reviewed to elucidate the instability of the d,-p, bond in high-valent (HV) Mn(X)O systems and the d,-p,-d, bond in HV MnOMn systems. The triplet instability of these bonds entails strong or intermediate diradical characters: ,Mn(IV)O, and ,MnOMn,; the BS MO resulted from strong electron correlation, leading to the concept of electron localizations and local spins. The BS computations have furthermore revealed guiding principles for derivation of selection rules for radical reactions of local spins. As a continuation of these theoretical results, the BS MO interaction diagrams for oxygen-radical coupling reactions in the oxygen evolution complex (OEC) in the PSII have been depicted to reveal scope and applicability of local singlet diradical (LSD) and local triplet diradical (LTD) mechanisms that have been successfully utilized for theoretical understanding of oxygenation reactions mechanisms by p450 and methane monooxygenase (MMO). The manganese-oxide cluster models examined are London, Berlin, and Berkeley models of CaMn4O4 and related clusters Mn4O4 and Mn3Ca. The BS MO interaction diagrams have revealed the LSD and/or LTD mechanisms for generation of molecular oxygen in the total low-, intermediate and high-spin states of these clusters. The spin alignments are found directly corresponding to the spin-coupling mechanisms of oxygen-radical sites in these clusters. The BS UB3LYP calculations of the clusters have been performed to confirm the comprehensive guiding principles for oxygen evolution; charge and spin densities by BS UB3LYP are utilized for elucidation and confirmation of the LSD and LTD mechanisms. Applicability of the proposed selection rules are examined in comparison with a lot of accumulated experimental and theoretical results for oxygen evolution reactions in native and artificial PSII systems. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] The role of the Frontier orbitals in acid,base chemistry of organic amines probed by ab initio and chemometric techniquesINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 11 2010Felipe A. La Porta Abstract The Frontier effective-for-reaction molecular orbital (FERMO) concept emerges as a powerful and innovative implement to investigate the role of molecular orbitals (MOs) applied in the description of breakage and formation of chemical bonds. In this work, theoretical calculations were carried out for conjugated acids of 18 amines and their acid,base behavior was analyzed using MO energies. We observed that highest occupied MO (HOMO) energies are inadequate to describe the acid,base behavior of these compounds. By using the FERMO concept, the reactions that are driven by HOMO, and those that are not, can be better explained, independent of the calculation method used, as independent of the calculation method used, both HF and Kohn,Sham methodologies lead to the same FERMO. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] Theory of chemical bonds in metalloenzymes XIII: Singlet and triplet diradical mechanisms of hydroxylations with iron-oxo species and P450 are revisitedINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2009Kizashi Yamaguchi Abstract Electronic structures of the Compound I (CpdI) in P450 are investigated on the basis of spin coupling forms of iron-oxo (Fe(IV)O) cores and radical ligand (,L) groups to generalize previous singlet and triplet diradical (TD) mechanisms for oxygenations of alkanes with Fe( IV)O. Orbital interaction schemes for four lower-lying spin configurations of CpdI with HC bond of substrate are examined to elucidate how magnetic coupling modes correlate with radical reaction pathways for hydroxylation reactions on the basis of the broken symmetry (BS) molecular orbital (MO) model. The configuration correlation diagrams for the four configurations model are depicted on the basis of the isoelectronic analogy among O, O2, and Fe( IV)O, in addition to Coulomb exchange energy on the iron site, which determines its local spin configuration. Important role of ligand spin (,L) of CpdI for regulation of hydroxylation mechanisms is clarified with the aid of the spin coupling forms. Transition states for one quartet and three doublet configurations under the BS MO approximation are examined on the basis of potential curve crossings along reaction pathways. The four transition structures and corresponding radical intermediates for methane and trimethyl methane with CpI are located by the BS hybrid Kohn,Sham density functional theory (DFT) (B3LYP) method to confirm the orbital interaction schemes. Spin density populations obtained by the BS B3LYP calculations are found to be consistent with the theoretical predictions based on the four configurations model. The configuration and state correlation diagrams by BS B3LYP before and after spin projection are also consistent with the BS MO interaction schemes, which provide local SD and TD mechanisms of hydroxylation with CpdI. The present BS MO-theoretical framework is useful for systematic understanding of a lot of recent BS hybrid DFT computational results for hydroxylation reactions with CpdI and configuration correlation diagrams reported by several groups. Implications of the present theoretical and computational results are discussed in relation to several experimental characteristics of hydroxylation reactions with iron-oxo species and P450. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Extended Hartree,Fock theory of chemical reactions.INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2009Abstract Symmetry and broken symmetry (BS) in molecular orbital description of transition structures and intermediates in oxygenation reactions have been revisited to elucidate states correlation diagrams and mechanisms for addition reactions of molecular oxygen and metal-oxo MO (M = Mn(II) and Fe(II)) species to CC double bonds. Relative stabilities between diradical (DR) and perepoxide (PE) intermediates were thoroughly investigated by several BS hybrid DFT (HDFT) methods and BS CCSD(T) method with and without spin projection. It has been found that recovery of spin symmetry, namely eliminating spin contamination error from the BS solutions, is crucial for the elucidation of reasonable state correlation diagrams and energy differences of the key structures in the oxygenation reactions because the singlet-triplet energy gap for molecular oxygen is large (22 kcal/mol). The BS HDFT followed by spin correction reproduced activation barriers for transition structures along both PE and DR reaction pathways by the use of the CASPT2 method. Basis set dependence on the relative stability between PE and DR intermediates were also examined thoroughly. Solvation effect for DR and PE intermediates was further examined with self-consistent reaction field (SCRF) and SCIPCM methods. Both BS HDFT and CASPT2 have concluded that the DR mechanism is favorable for the addition reaction of singlet oxygen to ethylene, supporting our previous conclusions. The BS HDFT with spin correction was concluded to be useful enough for theoretical investigations of mechanisms of oxygenation reactions. Implications of the computational results were discussed in relation to the theoretical framework (four configuration model) for elucidation of possible mechanisms of epoxidation reactions with Fe(IV)O cores in metalloenzymes on the basis of isolobal analogies among O, OO, and Fe(IV)O. Correspondence between magnetic coupling mode and radical pathway in oxygenations with these species was clarified based on the BS MO interaction diagrams, leading to local singlet and triplet diradical mechanisms for epoxidations. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] Charge transfer in single- and double-strand DNAs: Theoretical analysis based on molecular orbital methodINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2006Kenichi Dedachi Abstract Electrochemical DNA chips determine the sequence of DNA bases by detecting the change in charge conductivity through single- or double-strand DNA. Experimentally, double-strand DNAs were found to conduct much greater electric current than single-strand DNAs. To gain insight into the underlying mechanism leading to such a disparity in charge conductivity, the hole/electron conductivities in single- and double-strand DNAs were examined theoretically by molecular dynamics and molecular orbital (MO) calculations. The hole/electron transfer integrals between the neighboring DNA bases were estimated from the frontier MO energy levels. The current-voltage characteristics of single- and double-strand DNAs, derived from the transfer integrals and the site energy of each DNA base, are qualitatively in agreement with experiment. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source] Experimental and DFT calculated structure of the diruthenium(2.5) complex [(Me3TACN)Ru(,-Cl)3Ru(Me3TACN)](PF6)2ISRAEL JOURNAL OF CHEMISTRY, Issue 3 2001Wolfgang Kaim The diruthenium(2.5) complex [(Me3TACN)Ru(,-Cl)3Ru(Me3TACN)]-(PF6)2, Me3TACN = 1,4,7-trimethyl-1,4,7-triazacyclononane, has been crystallized for structural characterization. The results are reproduced by density functional theory (DFT) calculations and confirm the sensitivity of the central Ru(,-Cl)3Ru core to contacts between the Cl bridging atoms and the co-ligands. The singly occupied MO is characterized as a ,* MO involving the metal dz2 orbitals and a small halide contribution by DFT calculations and EPR. [source] Evaluation of the Video Intubation Unit in morbid obese patientsACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 1 2010I. BATHORY Background: Tracheal intubation may be more difficult in morbidly obese (MO) patients than in the non-obese. The aim of this study was to evaluate clinically if the use of the Video Intubation Unit (VIU), a video-optical intubation stylet, could improve the laryngoscopic view compared with the standard Macintosh laryngoscope in this specific population. Methods: We studied 40 MO patients (body mass index >35 kg/m2) scheduled for bariatric surgery. Each patient had a conventional laryngoscopy and a VIU inspection. The laryngoscopic grades (LG) using the Cormack and Lehane scoring system were noted and compared. Thereafter, the patients were randomised to be intubated with one of the two techniques. In one group, the patients were intubated with the help of the VIU and in the control group, tracheal intubation was performed conventionally. The duration of intubation, as well as the minimal SpO2 achieved during the procedure, were measured. Results: Patient characteristics were similar in both groups. Seventeen patients had a direct LG of 2 or 3 (no patient had a grade of 4). Out of these 17 patients, the LG systematically improved with the VIU and always attained grade 1 (P<0.0001). The intubation time was shorter within the VIU group, but did not attain significance. There was no difference in the SpO2 post-intubation. Conclusion: In MO patients, the use of the VIU significantly improves the visualisation of the larynx, thereby improving the intubation conditions. [source] Evaluation of the potential of polymeric carriers based on chitosan- grafted -polyacrylonitrile in the formulation of drug delivery systemsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2010A. A. Sarhan Abstract Graft copolymerization of chitosan with acrylonitrile (AN) was carried out by free radical polymerization using KMnO4 and oxalic acid as a combined redox initiator system. Graft copolymerization was confirmed by Fourier transform infrared spectra (FTIR), proton nuclear magnetic resonance spectra (1H-NMR), thermal gravimetric analysis (TGA) measurements, and wide angle X-ray diffraction (WAXD). In addition, further modification of the cyano groups of the grafted copolymers was performed by partial hydrolysis into carboxylic function groups with various extents. The extent of hydrolysis was monitored using FTIR spectroscopy. The potential of the hydrolyzed and unhydrolyzed grafted copolymers as polymeric carriers for drug delivery systems was extensively studied by preparation of tablets incorporated with methyl orange (MO) as a drug model. In vitro drug release was carried out in simulated gastric and intestinal conditions. The effects of grafting percentage (GP) and the extent of hydrolysis on the release kinetics were evaluated. Release continued up to 24 h for both hydrolyzed and unhydrolysed chitosan- g -PAN copolymers. The nature of drug transport through the polymer matrices was studied by comparing with power law or Kormeyer-Peppas equation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] A valence bond study of the dioxygen moleculeJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 1 2007Peifeng Su Abstract The dioxygen molecule has been the subject of valence bond (VB) studies since 1930s, as it was considered as the first "failure" of VB theory. The object of this article is to provide an unambiguous VB interpretation for the nature of chemical bonding of the molecule by means of modern VB computational methods, VBSCF, BOVB, and VBCI. It is shown that though the VBSCF method can not provide quantitative accuracy for the strongly electronegative and electron-delocalized molecule because of the lack of dynamic correlation, it still gives a correct qualitative analysis for wave function of the molecule and provides intuitive insights into chemical bonding. An accurate quantitative description for the molecule requires higher levels of VB methods that incorporate dynamic correlation. The potential energy curves of the molecule are computed at the various VB levels. It is shown that there exists a small hump in the PECs of VBSCF for the ground state, as found in previous studies. However, higher levels of VB methods dissolve the hump. The BOVB and VBCI methods reproduce the dissociation energies and other physical properties of the ground state and the two lowest excited states in very good agreement with experiment and with sophisticated MO based methods, such as the MRCI method. © 2006 Wiley Periodicals, Inc. J Comput Chem, 2007 [source] Medullary motor neurones associated with drinking behaviour of Japanese eelsJOURNAL OF FISH BIOLOGY, Issue 1 2003T. Mukuda A fluorescent dye, Evans blue (EB), was injected into the following seven drinking-associated muscles of the Japanese eel Anguilla japonica: the sternohyoid, third branchial, fourth branchial, opercular, pharyngeal, upper oesophageal sphincter and oesophageal body muscles. The sternohyoid muscle promotes ,ingestion', and the remaining muscles contribute to ,swallowing'. All neurones stained by EB were located ipsilaterally in the caudal medulla oblongata (MO) of the Japanese eel. Neurones projecting into the sternohyoid muscle were identified as those in the spino-occipital motor nucleus (NSO), and neurones projecting into the remaining muscles as those in the glossopharyngeal,vagal motor complex (GVC). Within the GVC, the neuronal arrangement was topological, and hence, ,swallowing' will be completed if the GVC neurones ,fire' progressively from rostral to caudal. These neurones in the NSO and GVC may use acetylcholine (ACh) as a neurotransmitter, as the EB-positive neurones in both nuclei were immunoreactive against anticholine acetyltransferase (anti-ChAT) antibody. Besides the MO, some somata in a ganglion of the vagal nerve were also stained by EB injected into the pharyngeal, the upper oesophageal sphincter and the oesophageal body muscles. The localization and the shape of the somata suggest that they are sensory neurones. These sensory neurones were not ChAT-immunoreactive. Combining these results, based on a model for ,swallowing' in mammals, a plausible model for central organization of ,drinking' in the Japanese eel is proposed, which suggests that ,drinking' in the fishes is regulated by the neuronal circuit for ,swallowing' in mammals. [source] FREE RADICAL-SCAVENGING ACTIVITIES OF LOW MOLECULAR WEIGHT CHITIN OLIGOSACCHARIDES LEAD TO ANTIOXIDANT EFFECT IN LIVE CELLSJOURNAL OF FOOD BIOCHEMISTRY, Issue 2010DAI-NGHIEP NGO ABSTRACT Chitin oligosaccharides (NA-COS) with low molecular weight distribution of 229.21,593.12 Da were produced from crab chitin by acid hydrolysis. They showed reducing power and scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) (Sigma Chemical Co., St. Louis, MO), hydroxyl and alkyl radicals. It was observed that the radical-scavenging activity of NA-COS increased in a dose-dependent manner. Their IC50 values for DPPH, hydroxyl and alkyl radicals were 0.8, 1.75 and 1.14 mg/mL, respectively. Furthermore, NA-COS exhibited the inhibitory effect on the oxidative damage of DNA from human lymphoma U937 (American Type Culture Collection, Manassas, VA) and the direct radical-scavenging effect in human fibrosarcoma cells (HT1080) (American Type Culture Collection) in 2,,7,-dichlorofluorescin diacetate (DCFH-DA) assay (Molecular Probes Inc., Eugene, OR). The results suggest that NA-COS can exert antioxidant effect in live cells and have the potential to be applied to food supplements or nutraceuticals. PRACTICAL APPLICATIONS Chitin oligosaccharides (NA-COS) are the hydrolyzed products of chitin (KEUMHO chemical products Co. Ltd., Gyeongbuk, Korea) of which derivatives have shown antioxidant, antimicrobial, anticancer, anti-inflammatory and immunostimulant effects. According to previous studies, NA-COS have beneficial biological activities similar to those of chitin. Furthermore, they are easily soluble in water because of their shorter chain length. Therefore, NA-COS are potentially applicable to improve food quality and human health. [source] EFFECTS OF MUSCLE PROTEASES, ENDOGENOUS PROTEASE INHIBITORS AND MYOFIBRIL FRAGMENTATION ON POSTMORTEM AGING OF GOAT MEATJOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2006N.S. NAGARAJ ABSTRACT The present study was conducted to evaluate the extent of postmortem proteolysis in longissimus dorsi, biceps femoris, semimembranosus and semitendinosus goat muscles on postmortem aging at an ambient (27C) temperature. The activities of calpains and calpastatin were determined after separation on a (diethylamino)ethyl,Sephacel column (Sigma, St. Louis, MO) and cathepsin (B, B + L and H) by carboxymethyl,Sepharose column (Sigma). The results showed that the decrease in calpain I and calpastatin activities was significantly higher than that of calpain II. Cathepsin B, B + L, H and cystatin were found to fall by 30,80% after 12 h, whereas cathepsin D decreased significantly in all the muscles. The disappearance of titin 1 and nebulin, and the appearance of a 30-kDa component were confirmed by Western blot analysis. The appearance of the 30-kDa component reported here explains the time-induced structural changes of myofibrils. The Z-line degradation had occurred by 6 h postmortem. Cathepsins are not stable compared to calpains during postmortem aging, and both enzymes may play a significant role in the proteolysis of myofibrillar proteins at ambient temperature. [source] EFFECT OF FROZEN TEMPERATURE AND STORAGE TIME ON CALPAINS, CATHEPSINS (B, B + L, H AND D) AND THEIR ENDOGENOUS INHIBITORS IN GOAT MUSCLESJOURNAL OF FOOD BIOCHEMISTRY, Issue 2 2006N.S. NAGARAJ ABSTRACT The effects of frozen storage on the biochemical properties of myofibrils, muscle proteinases (cathepsins and calpains) and their endogenous inhibitors were investigated. Longissimus dorsi, biceps femoris, semimembranosus and semitendinosus muscles from goat were frozen (,15C) and studied up to 120 days. The results showed that the percentage change in sarcomere length was 8.4,13.1. The calpain activity was determined after separation on a diethylaminoethyl,Sephacel column (Sigma, St. Louis, MO). Significantly greater percentage of calpain II activity was recovered when compared to calpain I. There was a 15,25% loss in calpastatin inhibitory activity, and the cystatin level fell by 11,16% after 80 days. Cathepsin B, B + L, H and D were very stable when compared to calpains. The calcium concentration may also be the factor for calpain activation. The sodium dodecyl sulfate,polyacrylamide gel electrophoresis result showed the appearance of 55 kDa components. It was concluded that calpains, not cathepsins, play an important role in the proteolysis of myofibrillar proteins at the freezing temperature. [source] A classification of computer security incidents based on reported attack dataJOURNAL OF INVESTIGATIVE PSYCHOLOGY AND OFFENDER PROFILING, Issue 2 2005Maria Kjaerland Abstract Previous studies of computer criminals have attempted to differentiate between offenders, but have not used data from the actual attacks. Drawing on theories from investigative psychology as well as information security, the current study differentiates 2755 computer security incidents using information about Method of Operation (MO), Impact, and Source Sector from reported attacks. Multivariate statistical analyses were applied on the data-matrix of 22 variables and showed the co-occurrences of various aspects of computer security incidents. A radex structure emerged where the high frequency variables were positioned in the centre of the data-plot. Based on a previously developed taxonomy of cyber intrusions, the results of the analysis showed that it was possible to draw inferences about the less informative category of Objective, from information about Attacker, Tools, Access, and Results. By applying the division-lines indicating the Objectives of Challenge/Status, Destruction, Political Gain and Financial Gain on the SSA-plot, it was shown how the taxonomies could be further developed by taking into account the relationships between the categories. Copyright © 2005 John Wiley & Sons, Ltd. [source] Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyesJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 8 2009I. V. Shmigol Abstract Desorption/ionization on silicon (DIOS) mass spectra of model ionic dyes methylene blue (MB+Cl,) and methyl orange (Na+MO,) were studied using p+ type-derived porous silicon (PS) free layers. As-prepared PS (PS-H), the PS thermally oxidized at 300 °C (PS-OX), PS with chemically grafted cation-exchanging alkylsulfonic acid (PS-SO3H) and anion-exchanging propyl-octadecyldimethylammonium chloride (PS-ODMA+Cl,) groups was tested as ionization platforms. Two mechanisms of the methylene blue desorption/ionization were found: (1) the formation of [MB + H]+, ion due to the reduction/protonation of MB+, which is predominant for PS-H and PS-OX platforms and (2) direct thermal desorption of the MB+ cation, prevailing for PS-SO3H. The fragmentation of the cation is significantly suppressed in the latter case. The samples of PS-SO3H and PS-ODMA+ Cl, efficiently adsorb the dyes of the opposite charge from their solutions via the ion-exchange. Consequent DIOS MS studies allow to detect only low fragmented ions (MB+ and MO,, respectively), demonstrating the potential of the ion-exchange adsorption combined with DIOS MS for the analysis of ionic organic compounds in solutions. 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