Computational Chemical Kinetics for the Reaction of Criegee Intermediate CH2OO with HNO3 and Its Catalytic Conversion to OH and HCO.

The kinetics and mechanisms for the reaction of the Criegee intermediate CH2OO with HNO3 and the unimolecular decomposition of its reaction product CH2(O)NO3 are important in atmospheric chemistry. The potential-energy profile of the reactions predicted with the CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ method shows that the initial association yields a prereaction complex that isomerizes by H migration to yield excited intermediate nitrooxymethyl hydroperoxide NO3CH2OOH* with internal energy ∼44 kcal mol-1. A fragmentation of this excited intermediate produces CH2(O)NO3 + OH with its transition state located 5.0 kcal mol-1 below that of the reactants. Further decomposition of CH2(O)NO3 produces HCO + HNO3, forming a catalytic cycle for destruction of CH2OO by HNO3. The rate coefficients and product-branching ratios were calculated in the temperature range 250-700 K at pressure 20-760 Torr (N2) using the variational-transition-state and Rice-Ramsperger-Kassel-Marcus (RRKM) theories. The predicted total rate coefficient for reaction CH2OO + HNO3 at 295 K, 5.1 × 10-10 cm3 molecule-1 s-1, agrees satisfactorily with the experimental value, (5.4 ± 1.0) × 10-10 cm3 molecule-1 s-1. The predicted branching ratios at 295 K are 0.21 for the formation of NO3CH2OOH and 0.79 for CH2(O)NO3 + OH at a pressure of 40 Torr (N2), and 0.79 for the formation of NO3CH2OOH and 0.21 for CH2(O)NO3 + OH at 760 Torr (N2). This new catalytic conversion of CH2OO to HCO + OH by HNO3 might have significant impact on atmospheric chemistry.

Ab Initio Chemical Kinetics for the CH3 + O((3)P) Reaction and Related Isomerization-Decomposition of CH3O and CH2OH Radicals.

The kinetics and mechanism of the CH3 + O reaction and related isomerization-decomposition of CH3O and CH2OH radicals have been studied by ab initio molecular orbital theory based on the CCSD(T)/aug-cc-pVTZ//CCSD/aug-cc-pVTZ, CCSD/aug-cc-pVDZ, and G2M//B3LYP/6-311+G(3df,2p) levels of theory. The predicted potential energy surface of the CH3 + O reaction shows that the CHO + H2 products can be directly generated from CH3O by the TS3 → LM1 → TS7 → LM2 → TS4 path, in which both LM1 and LM2 are very loose and TS7 is roaming-like. The result for the CH2O + H reaction shows that there are three low-energy barrier processes including CH2O + H → CHO + H2 via H-abstraction and CH2O + H → CH2OH and CH2O + H → CH3O by addition reactions. The predicted enthalpies of formation of the CH2OH and CH3O radicals at 0 K are in good agreement with available experimental data. Furthermore, the rate constants for the forward and some key reverse reactions have been predicted at 200-3000 K under various pressures. Based on the new reaction pathway for CH3 + O, the rate constants for the CH2O + H and CHO + H2 reactions were predicted with the microcanonical variational transition-state/Rice-Ramsperger-Kassel-Marcus (VTST/RRKM) theory. The predicted total and individual product branching ratios (i.e., CO versus CH2O) are in good agreement with experimental data. The rate constant for the hydrogen abstraction reaction of CH2O + H has been calculated by the canonical variational transition-state theory with quantum tunneling and small-curvature corrections to be k(CH2O + H → CHO + H2) = 2.28 × 10(-19) T(2.65) exp(-766.5/T) cm(3) molecule(-1) s(-1) for the 200-3000 K temperature range. The rate constants for the addition giving CH3O and CH2OH and the decomposition of the two radicals have been calculated by the microcanonical RRKM theory with the time-dependent master equation solution of the multiple quantum well system in the 200-3000 K temperature range at 1 Torr to 100 atm. The predicted rate constants are in good agreement with most of the available data.

Correlation of HOXD3 promoter hypermethylation with clinical and pathologic features in screening prostate biopsies.

BACKGROUND: Molecular markers that can discriminate indolent cancers from aggressive ones may improve the management of prostate cancer and minimize unnecessary treatment.Aberrant DNA methylation is a common epigenetic event in cancers and HOXD3 promoter hypermethylation (H3PH) has been found in prostate cancer. Our objective was to evaluate the relationship between H3PH and clinicopathologic features in screening prostate biopsies. METHODS: Ninety-two patients who underwent a prostate biopsy at our institution between October 2011 and May 2012 were included in this study. The core with the greatest percentage of the highest grade disease was analyzed for H3PH by methylation-specific PCR. Correlational analysis was used to analyze the relationship between H3PH and various clinical parameters. Chi-square analysis was used to compare H3PH status between benign and malignant disease. RESULTS: Of the 80 biopsies with HOXD3 methylation status assessable, 66 sets were confirmed to have cancer. In the 14 biopsies with benign disease there was minimal H3PH with the mean percentage of methylation reference (PMR) of 0.7%. In contrast, the HOXD3 promoter was hypermethylated in 16.7% of all cancers and in 50% of high risk tumors with an average PMR of 4.3% (P=0.008). H3PH was significantly correlated with age (P=0.013), Gleason score (P=0.031) and the maximum involvement of the biopsy core (P=0.035). CONCLUSIONS: H3PH is associated with clinicopathologic features. The data indicate that H3PH is more common in older higher risk patients. More research is needed to determine the role of this marker in optimizing management strategies in men with newly diagnosed prostate cancer.

Ab initio chemical kinetics for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the related unimolecular decomposition of Si3H8 under a-Si/H CVD conditions.

The kinetics and mechanisms for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the related unimolecular decomposition of Si3H8 have been investigated by ab initio molecular orbital theory based on the QCISD(T)/CBS//QCISD/6-311++G(d,p) method in conjunction with quantum statistical variational Rice-Ramsperger-Kassel-Marcus (RRKM) calculations. For the barrierless radical association processes, their variational transition states have been characterized by the CASPT2//CASSCF method. The species involved in the study are known to coexist under CVD conditions. The results show that the association reaction of SiH2 and Si2H6 producing Si3H8 occurs by insertion via its lowest-energy path forming a loose hydrogen-bonding molecular complex with 8.3 kcal/mol binding energy; the reaction is exothermic by 55.0 kcal/mol. The chemically activated Si3H8 adduct can fragment by several paths, producing SiH4 + SiH3SiH (-0.7 kcal/mol), Si(SiH3)2 + H2 (-1.4 kcal/mol), and SiH3SiH2SiH + H2 (-1.4 kcal/mol). The predicted enthalpy changes as given agree well with available thermochemical data. Three other decomposition channels of Si3H8 occurring by Si-H or Si-Si breaking were found to be highly endothermic, and the reactions take place without a well-defined barrier. The heats of formation of Si3H8, SiH2SiH, Si2H4, i-Si3H7, n-Si3H7, Si(SiH3)2, and SiH3SiH2SiH have been predicted and found to be in close agreement with those available data in the literature. The product branching rate constants for SiH2 + Si2H6 and SiH3 + Si2H5 reactions and the thermal unimolecular decomposition of Si3H8 for all low-energy paths have been calculated with multichannel variational RRKM theory covering varying P,T conditions typically employed in PECVD and Cat-CVD processes for hydrogenated amorphous silicon (a-Si/H) film growth. The results were also found to be in good agreement with available kinetic data. Our kinetic results may be employed to model and control very large-area a-Si/H film growth for a new generation of solar cell applications.

Effect of roaming transition states upon product branching in the thermal decomposition of CH3NO2.

The kinetics for the thermal unimolecular decomposition of CH3NO2 and its structural isomer CH3ONO have been investigated by statistical theory calculations based on the potential energy surface calculated at the UCCSD(T)/CBS and CASPT3(8, 8)/6-311+G(3df,2p) levels. Our results show that for the decomposition of CH3NO2 at pressures less than 2 Torr, isomerization to CH3ONO via the recently located roaming transition state is dominant in the entire temperature range studied, 400-3000 K. However, at higher pressures, the formation of the commonly assumed products, CH3 + NO2, becomes competitive and at pressures higher than 200 Torr the production of CH3 + NO2 is exclusive. The predicted rate constants for 760 Torr and the high-pressure limit with Ar as diluent in the temperature range 500-3000 K, producing solely CH3 + NO2, can be expressed respectively by kd(760)(CH3NO2) = 2.94 × 10(55)T(-12.6) exp(-35500/T) s(-1) and kd(∞)(CH3NO2) = 5.88 × 10(24)T(-2.35) exp(-31400/T) s(-1). In the low pressure limit, the decomposition reaction takes place exclusively via the roaming TS producing internally excited CH3ONO, giving rise to both CH3O + NO and CH2O + HNO with the second-order rate constant kd(0)(CH3NO2) = 1.17 × 10(31)T(-10.94) exp(-32400/T) cm(3) molecule(-1) s(-1). For CH3ONO decomposition, a new roaming transition state connecting to the CH2O + HNO products has been located, lying 6.8 kcal/mol below the well-known four-member ring tight transition state and 0.7 kcal/mol below CH3O + NO. The rate constants predicted by similar calculations give rise to the following expressions for the thermal decomposition of CH3ONO in He: kd(760)(CH3ONO) = 8.75 × 10(41)T(-8.97) exp(-22600/T) s(-1) and kd(∞)(CH3ONO) = 1.58 × 10(23)T(-2.18) exp(-21100/T) s(-1) in the temperature range 300-3000 K. These results are in very good agreement with available experimental data obtained under practical pressure conditions. The much different branching ratios for the formation of CH3O + NO and CH2O + HNO in the decomposition of both CH3NO2 and CH3ONO are also given in this work.

Quantum chemical elucidation of the mechanism for hydrogenation of TiO2 anatase crystals.

Hydrogenation of TiO2 is relevant to hydrogen storage and water splitting. We have carried out a detailed mechanistic study on TiO2 hydrogenation through H and∕or H2 diffusion from the surface into subsurface layers of anatase TiO2 (101) by periodic density functional theory calculations implementing on-site Coulomb interactions (DFT + U). Both H atoms and H2 molecules can migrate from the crystal surface into TiO2 near subsurface layer with 27.8 and 46.2 kcal∕mol energy barriers, respectively. The controlling step for the former process is the dissociative adsorption of H2 on the surface which requires 47.8 kcal∕mol of energy barrier. Both hydrogen incorporation processes are expected to be equally favorable. The barrier energy for H2 migration from the first layer of the subsurface Osub1 to the 2nd layer of the subsurface oxygen Osub2 requires only 6.6 kcal. The presence of H atoms on the surface and inside the subsurface layer tends to promote both H and H2 penetration into the subsurface layer by reducing their energy barriers, as well as to prevent the escape of the H2 from the cage by increasing its escaping barrier energy. The H2 molecule inside a cage can readily dissociate and form 2HO-species exothermically (ΔH = -31.0 kcal∕mol) with only 26.2 kcal∕mol barrier. The 2HO-species within the cage may further transform into H2O with a 22.0 kcal∕mol barrier and 19.3 kcal∕mol exothermicity relative to the caged H2 molecule. H2O formation following the breaking of Ti-O bonds within the cage may result in the formation of O-vacancies and surface disordering as observed experimentally under a high pressure and moderately high temperature condition. According to density of states analysis, the projected density of states of the interstitial H, H2, and H2O appear prominently within the TiO2 band gap; in addition, the former induces a shift of the band gap position notably towards the conduction band. The thermochemistry for formation of the most stable sub-surface species (2HO and H2O) has been predicted. These results satisfactorily account for the photo-catalytic activity enhancement observed experimentally by hydrogenation at high temperatures and high pressures.

Ab initio chemical kinetics for the ClOO + NO reaction: effects of temperature and pressure on product branching formation.

The kinetics and mechanism for the reaction of ClOO with NO have been investigated by ab initio molecular orbital theory calculations based on the CCSD(T)/6-311+G(3df)//PW91PW91∕6-311+G(3df) method, employed to evaluate the energetics for the construction of potential energy surfaces and prediction of reaction rate constants. The results show that the reaction can produce two key low energy products ClNO + (3)O(2) via the direct triplet abstraction path and ClO + NO(2) via the association and decomposition mechanism through long-lived singlet pc-ClOONO and ClONO(2) intermediates. The yield of ClNO + O(2) ((1)△) from any of the singlet intermediates was found to be negligible because of their high barriers and tight transition states. As both key reactions initially occur barrierlessly, their rate constants were evaluated with a canonical variational approach in our transition state theory and Rice-Ramspergen-Kassel-Marcus/master equation calculations. The rate constants for ClNO + (3)O(2) and ClO + NO(2) production from ClOO + NO can be given by 2.66 × 10(-16) T(1.91) exp(341/T) (200-700 K) and 1.48 × 10(-24) T(3.99) exp(1711/T) (200-600 K), respectively, independent of pressure below atmospheric pressure. The predicted total rate constant and the yields of ClNO and NO(2) in the temperature range of 200-700 K at 10-760 Torr pressure are in close agreement with available experimental results.

Computational study on the reactions of H2O2 on TiO2 anatase (101) and rutile (110) surfaces.

This study investigates the adsorption and reactions of H(2)O(2) on TiO(2) anatase (101) and rutile (110) surfaces by first-principles calculations based on the density functional theory in conjunction with the projected augmented wave approach, using PW91, PBE, and revPBE functionals. Adsorption mechanisms of H(2)O(2) and its fragments on both surfaces are analyzed. It is found that H(2)O(2) , H(2)O, and HO preferentially adsorb at the Ti(5c) site, meanwhile HOO, O, and H preferentially adsorb at the (O(2c))(Ti(5c)), (Ti(5c))(2), and O(2c) sites, respectively. Potential energy profiles of the adsorption processes on both surfaces have been constructed using the nudged elastic band method. The two restructured surfaces, the 1/3 ML oxygen covered TiO(2) and the hydroxylated TiO(2), are produced with the H(2)O(2) dehydration and deoxidation, respectively. The formation of main products, H(2)O(g) and the 1/3 ML oxygen covered TiO(2) surface, is exothermic by 2.8 and 5.0 kcal/mol, requiring energy barriers of 0.8 and 1.1 kcal/mol on the rutile (110) and anatase (101) surface, respectively. The rate constants for the H(2)O(2) dehydration processes have been predicted to be 6.65 × 10(-27) T(4.38) exp(-0.14 kcal mol(-1)/RT) and 3.18 × 10(-23) T(5.60) exp(-2.92 kcal mol(-1)/RT) respectively, in units of cm(3) molecule(-1) s(-1).

Computational investigation of O2 reduction and diffusion on 25% Sr-doped LaMnO3 cathodes in solid oxide fuel cells.

The oxygen reduction reaction (ORR) and diffusion mechanisms on 25% Sr-doped LaMnO(3) (LSM) cathode materials as well as their kinetic behavior have been studied by using spin-polarized density functional theory (DFT) calculations. Bader charge and frequency analyses were carried out to identify the oxidation state of adsorbed oxygen species. DFT and molecular dynamics (MD) results show that the fast O(2) adsorption/reduction process via superoxide and peroxide intermediates is energetically favorable on the Mn site rather than on the Sr site. Furthermore, the higher adsorption energies on the Mn site of the (110) surface compared to those on the (100) surface imply that the former is more efficient for O(2) reduction. Significantly, we predict that oxygen vacancies enhance O(2) reduction kinetics and that the O-ion migration through the bulk is dominant over that on the surface of the LSM cathode.

Annexin-V imaging for noninvasive detection of cardiac allograft rejection.

Heart transplant rejection is characterized pathologically by myocyte necrosis and apoptosis associated with interstitial mononuclear cell infiltration. Any one of these components can be targeted for noninvasive detection of transplant rejection. During apoptotic cell death, phosphatidylserine, a phospholipid that is normally confined to the inner leaflet of cell membrane bilayer, gets exteriorized. Technetium-99m-labeled annexin-V, an endogenous protein that has high affinity for binding to phosphatidylserine, has been administered intravenously for noninvasive identification of apoptotic cell death. In the present study of 18 cardiac allograft recipients, 13 patients had negative and five had positive myocardial uptake of annexin. These latter five demonstrated at least moderate transplant rejection and caspase-3 staining, suggesting apoptosis in their biopsy specimens. This study reveals the clinical feasibility and safety of annexin-V imaging for noninvasive detection of transplant rejection by targeting cell membrane phospholipid alterations that are commonly associated with the process of apoptosis.

Basal cell cystadenoma of the lacrimal gland: diagnostic pitfalls of a basaloid pattern in lacrimal tumours.

An 85-year-old male experienced a painless swelling along the left lateral orbit for one year. A computed tomography scan demonstrated a cystic mass in the orbit adjacent to the lacrimal gland. There was a concern for malignancy considering the large size and the patient's age, so the tumour was excised. Histopathology of the tumour showed nests with basaloid patterns, but a definitive diagnosis was not rendered. The uncertainty of tissue diagnosis coupled with the basaloid pattern, which carries a grim prognosis in some salivary gland tumours, led us to refer this case to an authority on lacrimal gland pathology, who suggested that this tumour be called a basal cell cystadenoma. To the best of our knowledge, a basal cell cystadenoma of the lacrimal gland has not been reported in the literature. We present histopathological features that distinguish this tumour from malignant tumours with a basaloid pattern. We also discuss the management differences associated with basaloid patterns in lacrimal tumours.

Neuropsychiatric Symptoms and Caregiver's Burden in Parkinson's Disease Patients in a Tertiary Care Teaching Hospital in South India: A Cross-Sectional Study.

BACKGROUND: In patients with Parkinson's disease (PD), the occurrence of motor and non-motor symptoms increases with disease progression. The range of neuropsychiatric symptoms (NPS) vary among individuals and can be burdensome for caregivers. Only a few studies have identified the contributing factors of NPS and caregiver burden in India. OBJECTIVES: We aimed to study the clinical profile, disability, and predictive factors of NPS in PD patients and associated caregiver's burden. METHODS AND MATERIAL: This was a cross-sectional observational study carried out in PD patients and their respective caregivers attending a movement disorder clinic in a tertiary care teaching hospital in Kerala. A total of 104 patients diagnosed with idiopathic PD receiving levodopa therapy and who had a primary caregiver were enrolled in the study. Structured questionnaires were administered to both patients and caregivers to collect data. Data analysis was done using an independent t-test, linear, and multiple regression analysis. RESULTS: Among 104 patients recruited for the study, 61.5% of patients had shown at least one NPS and 40.44% showed multiple NPS. Results from the study showed that depression is the primary NPS occurring in IPD patients (55.8%) followed by irritability, anxiety, and apathy. On linear regression models, the prime determinant of NPS was the Everyday Abilities Scale for India (EASI). For caregiver burden, the main determinants were the presence of NPS, duration of caregiving, EASI, and RBDSQ score. CONCLUSIONS: NPS in PD are highly associated with and are determinants of caregiver burden. Detailed assessment and specific interventions aimed at NPS could alleviate caregiver burden.

Ab initio chemical kinetics for SiH3 reactions with Si(x)H2x+2 (x = 1-4).

Gas-phase kinetics and mechanisms of SiH(3) reactions with SiH(4), Si(2)H(6), Si(3)H(8), and Si(4)H(10), processes of relevance to a-Si thin-film deposition, have been investigated by ab initio molecular orbital and transition-state theory (TST) calculations. Geometric parameters of all the species involved in the title reactions were optimized by density functional theory at the B3LYP and BH&HLYP levels with the 6-311++G(3df,2p) basis set. The potential energy surface of each reaction was refined at the CCSD(T)/6-311++G(3df,2p) level of theory. The results show that the most favorable low energy pathways in the SiH(3) reactions with these silanes occur by H abstraction, leading to the formation of SiH(4) + Si(x)H(2x+1) (silanyl) radicals. For both Si(3)H(8) and n-Si(4)H(10) reactions, the lowest energy barrier channels take place by secondary Si-H abstraction, yielding SiH(4) + s-Si(3)H(7) and SiH(4) + s-Si(4)H(9), respectively. In the i-Si(4)H(10) reaction, tertiary Si-H abstraction has the lowest barrier producing SiH(4) + t-Si(4)H(9). In addition, direct SiH(3)-for-X substitution reactions forming Si(2)H(6) + X (X = H or silanyls) can also occur, but with significantly higher reaction barriers. A comparison of the SiH(3) reactions with the analogous CH(3) reactions with alkanes has been made. The rate constants for low-energy product channels have been calculated for the temperature range 300-2500 K by TST with Eckart tunneling corrections. These results, together with predicted heats of formation of various silanyl radicals and Si(4)H(10) isomers, have been tabulated for modeling of a-Si:H film growth by chemical vapor deposition.

Ab initio chemical kinetics for the reaction of an H atom with Si3H8.

The kinetics and mechanism for the reaction of H with Si(3)H(8) have been investigated using various theoretical methods including CCSD(T)/6-311++G(3df,2p)//B3LYP/6-311++G(3df,2p), G2M(RCC2), and CCSD(T)/6-311++G(3df,2p)//CCSD/6-311+G(d,p). The results obtained by the latter method show that H abstraction from a primary Si-H bond and a secondary Si-H bond leads to the formation of n-Si(3)H(7) and i-Si(3)H(7) products, with 3.8 (TS1) and 3.2 (TS2) kcal/mol barriers, respectively. Significantly, the hydrogen substitution of SiH(3) and Si(2)H(5) groups by attacking at the central Si atom via TS3 (3.3 kcal/mol) and a terminal Si atom of Si(3)H(8) from side and end on (via TS4, 4.2 kcal/mol and TS5, 6.3 kcal/mol), were found to give SiH(3) + Si(2)H(6) and SiH(4) + Si(2)H(5) products, respectively. The heats of formation of Si(3)H(8), n-Si(3)H(7), and i-Si(3)H(7) at 0 K are predicted to be 32.3 +/- 1.2, 68.6, and 66.6 kcal/mol, respectively. These values are in good agreement with the experimental and other theoretical values. The rate constants and branching ratios for the four product channels of the title reaction have been calculated by the transition state theory with Eckart tunneling corrections over a wide temperature region of 250-2500 K. These results may be employed for simulations of catalytic and plasma-enhanced chemical vapor deposition processes of a-Si:H films.

Ab initio chemical kinetic study for reactions of H atoms with SiH(4) and Si(2)H(6): comparison of theory and experiment.

The reactions of hydrogen atom with silane and disilane are relevant to the understanding of catalytic chemical vapor deposition (Cat-CVD) and plasma enhanced chemical vapor deposition (PECVD) processes. In the present study, these reactions have been investigated by means of ab initio molecular-orbital and transition-state theory calculations. In both reactions, the most favorable pathway was found to be the H abstraction leading to the formation of SiH(3) and Si(2)H(5) products, with 5.1 and 4.0 kca/mol barriers, respectively. For H + Si(2)H(6), another possible reaction pathway giving SiH(3) + SiH(4) may take place with two different mechanisms with 4.3 and 6.7 kcal/mol barriers for H-atom attacking side-way and end-on, respectively. To validate the calculated energies of the reactions, two isodesmic reactions, SiH(3)+CH(4)-->SiH(4)+CH(3) and Si(2)H(5)+C(2)H(6)-->Si(2)H(6)+C(2)H(5) were employed; the predicted heats of the formation for SiH(3) (49.0 kcal/mol) and Si(2)H(5) (58.6 kcal/mol) were found to agree well with the experimental data. Finally, rate constants for both H-abstraction reactions predicted in the range of 290-2500 K agree well with experimental data. The result also shows that H+Si(2)H(6) producing H(2)+Si(2)H(5) is more favorable than SiH(3)+SiH(4.).

Shock tube study on the thermal decomposition of CH3OH.

H atom produced in the thermal decomposition of CH(3)OH highly diluted in Ar (0.48-10 ppm) was monitored behind reflected shock waves by atomic resonance absorption spectrometry (ARAS) at fixed temperatures (and pressures), that is, 1660 (1.73 atm), 1760 (2.34 atm), 1860 (2.04 atm), 1950 (2.18 atm), and 2050 K (1.76 atm) (+/-10 K, respectively). High sensitivity for the H atom has been attained by signal averaging of the ARAS signals down to the concentrations of approximately 1 x 10(11) atoms/cm(3) and enables us to determine the branching fraction for the direct H atom production channel, CH(3)OH --> CH(2)OH + H (channel 1c ) in a mixture of 1 ppm CH(3)OH. Channel 1c is confirmed to be minor, that is, branching fraction for channel 1c is expressed by Log(k(1c)/k(1)) = (- 2.88 +/- 1.88) x 10(3)/T - (0.23 +/- 1.02), which corresponds to k(1c)/k(1) < 0.03 for the present temperature range. By using 0.48 and 1.0 ppm CH(3)OH with (100-1000) ppm H(2), the total decomposition rate k(1) for CH(3)OH --> products is measured from the time dependence of H atom, where the radical products of main channels 1a and 1b , that is, OH, CH(3), and CH(2), were converted rapidly into H atoms. The experimental result is summarized as Log(k(1)/cm(3)molecule(-1)s(-1)) = (-12.82 +/- 0.71) x 10(3)/T - (8.5 +/- 0.38). A theoretical study based on ab initio/TST calculations with high accuracy has been conducted for the reaction: (3)CH(2) + H(2) --> CH(3) + H (reaction 3 ). The rate is given by k(3)/cm(3)molecule(-1) s(-1) = (7.32 x 10(-19))T(2.3) exp (-3699/T). This result is used for numerical simulations to evaluate k(1). Present experimental results on the thermal decomposition rate of CH(3)OH are found to be consistent with previous works. It is also found that time dependence of [H] observed in the 10 ppm CH(3)OH in Ar can be reproduced very well by kinetic simulations by using a reaction mechanism composed of 36 elementary reactions.

Cloning and expression of an outer membrane protein OmpW of Aeromonas hydrophila and study of its distribution in Aeromonas spp.

AIMS: The main aims of this study were to clone and express an outer membrane protein (OMP), OmpW, of Aeromonas hydrophila and to study its distribution in Aeromonas spp. METHODS AND RESULTS: The gene encoding OmpW in A. hydrophila has been cloned and expressed in Escherichia coli. Primers were designed for amplification of full-length ompW gene and used for identification of this gene in different Aeromonas spp. Of the 42 Aeromonas strains tested, all the isolates were positive by polymerase chain reaction (PCR) except one strain of Aeromonas veronii biovar veronii (VTE338). None of the other gram-negative bacteria were positive by PCR with primers specific to ompW gene of A. hydrophila. Polyclonal antibodies were raised in rabbit against the purified recombinant protein and the reaction of these antibodies was confirmed by western blotting using the purified recombinant protein and 42 Aeromonas cultures grown at various salt concentrations. CONCLUSIONS: The ompW-based PCR method developed in this study was found to be 100% specific and 97% sensitive. Expression of OmpW protein of Aeromonas was found to be salt-dependant. Recombinant OmpW protein was found to be highly immunogenic in fish. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this is the first report on cloning and expression of OmpW protein of A. hydrophila. Full-length ompW gene amplification by PCR can be used for the detection of Aeromonas. Recombinant OmpW protein can be useful for vaccination of fish against Aeromonas spp.

Orbital metastasis of keratinizing squamous cell cervical carcinoma with giant cells. A case report.

A case of orbital metastasis of cervical keratinizing squamous cell carcinoma is presented. The patient, in remission from primary cervical and ovarian cancers, presented with complaints of left eye ptosis and pain. Examination revealed the presence of a moderately tender mass along the left supra-temporal orbital rim and downward displacement of the left globe. Computed tomography revealed a poorly circumscribed mass with superior lateral wall bone loss. Excised tissue contained invasive, poorly differentiated nests of pan keratin and epithelial membrane antigen-positive squamous cells with numerous pleomorphic multinucleated giant cells. Multiple treatment regimes were unsuccessful, and the patient expired due to disease complications after 3 months.

Oncogenic tyrosine kinase NPM/ALK induces activation of the MEK/ERK signaling pathway independently of c-Raf.

The mechanisms of cell transformation mediated by the highly oncogenic, chimeric NPM/ALK tyrosine kinase remain only partially understood. Here we report that cell lines and native tissues derived from the NPM/ALK-expressing T-cell lymphoma (ALK+ TCL) display phosphorylation of the extracellular signal-regulated protein kinase (ERK) 1/2 complex. Transfection of BaF3 cells with NPM/ALK induces phosphorylation of EKR1/2 and of its direct activator mitogen-induced extracellular kinase (MEK) 1/2. Depletion of NPM/ALK by small interfering RNA (siRNA) or its inhibition by WHI-154 abrogates the MEK1/2 and ERK1/2 phosphorylation. The NPM/ALK-induced MEK/ERK activation is independent of c-Raf as evidenced by the lack of MEK1/2 and ERK1/2 phosphorylation upon c-Raf inactivation by two different inhibitors, RI and ZM336372, and by its siRNA-mediated depletion. In contrast, ERK1/2 activation is strictly MEK1/2 dependent as shown by suppression of the ERK1/2 phosphorylation by the MEK1/2 inhibitor U0126. The U0126-mediated inhibition of ERK1/2 activation impaired proliferation and viability of the ALK+ TCL cells and expression of antiapoptotic factor Bcl-xL and cell cycle-promoting CDK4 and phospho-RB. Finally, siRNA-mediated depletion of both ERK1 and ERK2 inhibited cell proliferation, whereas depletion of ERK 1 (but not ERK2) markedly increased cell apoptosis. These findings identify MEK/ERK as a new signaling pathway activated by NPM/ALK and indicate that the pathway represents a novel therapeutic target in the ALK-induced malignancies.