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https://www.readbyqxmd.com/read/28758403/ab-initio-computations-and-active-thermochemical-tables-hand-in-hand-heats-of-formation-of-core-combustion-species
#1
Stephen J Klippenstein, Lawrence B Harding, Branko Ruscic
The fidelity of combustion simulations is strongly dependent on the accuracy of the underlying thermochemical properties for the core combustion species that arise as intermediates and products in the chemical conversion of most fuels. High level theoretical evaluations are coupled with a wide-ranging implementation of the Active Thermochemical Tables (ATcT) approach to obtain well-validated high fidelity predictions for the 0 K heat of formation for a large set of core combustion species. In particular, high level ab initio electronic structure based predictions are obtained for a set of 348 C, N, O, and H containing species, which corresponds to essentially all core combustion species with 34 or fewer electrons...
July 31, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28727457/enthalpy-of-formation-of-n2h4-hydrazine-revisited
#2
David Feller, David H Bross, Branko Ruscic
In order to address the accuracy of the long-standing experimental enthalpy of formation of gas-phase hydrazine, fully confirmed in earlier versions of Active Thermochemical Tables (ATcT), the provenance of that value is re-examined in light of new high-end calculations of the Feller-Peterson-Dixon (FPD) variety. An overly optimistic determination of the vaporization enthalpy of hydrazine, which created an unrealistically strong connection between the gas phase thermochemistry and the calorimetric results defining the thermochemistry of liquid hydrazine, was identified as the probable culprit...
August 4, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28636377/enthalpies-of-formation-of-hydrazine-and-its-derivatives
#3
Olga V Dorofeeva, Oxana N Ryzhova, Taisiya A Suchkova
Enthalpies of formation, ΔfH298(°), in both the gas and condensed phase, and enthalpies of sublimation or vaporization have been estimated for hydrazine, NH2NH2, and its 36 various derivatives using quantum chemical calculations. The composite G4 method has been used along with isodesmic reaction schemes to derive a set of self-consistent high-accuracy gas-phase enthalpies of formation. To estimate the enthalpies of sublimation and vaporization with reasonable accuracy (5-20 kJ/mol), the method of molecular electrostatic potential (MEP) has been used...
July 5, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28517940/thermal-decomposition-of-potential-ester-biofuels-part-i-methyl-acetate-and-methyl-butanoate
#4
Jessica P Porterfield, David H Bross, Branko Ruscic, James H Thorpe, Thanh Lam Nguyen, Joshua H Baraban, John F Stanton, John W Daily, G Barney Ellison
Two methyl esters were examined as models for the pyrolysis of biofuels. Dilute samples (0.06-0.13%) of methyl acetate (CH3COOCH3) and methyl butanoate (CH3CH2CH2COOCH3) were entrained in (He, Ar) carrier gas and decomposed in a set of flash-pyrolysis microreactors. The pyrolysis products resulting from the methyl esters were detected and identified by vacuum ultraviolet photoionization mass spectrometry. Complementary product identification was provided by matrix infrared absorption spectroscopy. Pyrolysis pressures in the pulsed microreactor were about 20 Torr and residence times through the reactors were roughly 25-150 μs...
June 9, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28345688/a-vacuum-ultraviolet-laser-pulsed-field-ionization-photoion-study-of-methane-ch4-determination-of-the-appearance-energy-of-methylium-from-methane-with-unprecedented-precision-and-the-resulting-impact-on-the-bond-dissociation-energies-of-ch4-and-ch4
#5
Yih-Chung Chang, Bo Xiong, David H Bross, Branko Ruscic, C Y Ng
We report on the successful implementation of a high-resolution vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) detection method for the study of unimolecular dissociation of quantum-state- or energy-selected molecular ions. As a test case, we have determined the 0 K appearance energy (AE0) for the formation of methylium, CH3(+), from methane, CH4, as AE0(CH3(+)/CH4) = 14.32271 ± 0.00013 eV. This value has a significantly smaller error limit, but is otherwise consistent with previous laboratory and/or synchrotron-based studies of this dissociative photoionization onset...
March 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28239467/ccr7-selected-gene-modified-t-cells-maintain-a-central-memory-phenotype-and-display-enhanced-persistence-in-peripheral-blood-in-vivo
#6
Gray Kueberuwa, Hannah Gornall, Erik Marcelo Alcantar-Orozco, Deborah Bouvier, Zainul Abedin Kapacee, Robert Edward Hawkins, David Edward Gilham
BACKGROUND: Adoptive T cell immunotherapy (ATCT) for cancer entails infusing patients with T cells that recognise and destroy tumour cells. Efficient engraftment of T cells and persistence in the circulation correlate with favourable clinical outcomes. T cells of early differentiation possess an increased capacity for proliferation and therefore persistence, using these cells for ATCT could therefore lead to improved clinical outcomes. METHOD: We describe a method to enrich T cells of early differentiation status using paramagnetic beads and antibodies targeting cells expressing C-C motif chemokine receptor 7 (CCR7)...
2017: Journal for Immunotherapy of Cancer
https://www.readbyqxmd.com/read/27583807/validation-of-a-database-of-formation-enthalpies-and-of-mid-level-model-chemistries
#7
J M Simmie, J N Sheahan
In order to test new procedures for the calculation of basic molecular properties, a properly validated database and computational method appropriate to the range of species at hand is essential. Here formation enthalpies of chemical species CmHnNpOq from their constituent atoms are computed by midlevel composite model chemistries in order to check the contents of the best established and most accurate database, ATcT. Once discrepancies are identified alternative independent procedures and/or higher level model chemistries, which include CCSDT(Q) calculations, are employed to resolve the problems...
September 22, 2016: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/27276939/toward-a-w4-f12-approach-can-explicitly-correlated-and-orbital-based-ab-initio-ccsd-t-limits-be-reconciled
#8
Nitai Sylvetsky, Kirk A Peterson, Amir Karton, Jan M L Martin
In the context of high-accuracy computational thermochemistry, the valence coupled cluster with all singles and doubles (CCSD) correlation component of molecular atomization energies presents the most severe basis set convergence problem, followed by the (T) component. In the present paper, we make a detailed comparison, for an expanded version of the W4-11 thermochemistry benchmark, between, on the one hand, orbital-based CCSD/AV{5,6}Z + d and CCSD/ACV{5,6}Z extrapolation, and on the other hand CCSD-F12b calculations with cc-pVQZ-F12 and cc-pV5Z-F12 basis sets...
June 7, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27043325/enthalpy-of-formation-and-o-h-bond-dissociation-enthalpy-of-phenol-inconsistency-between-theory-and-experiment
#9
Olga V Dorofeeva, Oxana N Ryzhova
Gas-phase O–H homolytic bond dissociation enthalpy in phenol, DH298°(C6H5O–H), is still disputed, despite a large number of experimental and computational studies. In estimating this value, the experimental enthalpy of formation of phenol, ΔfH298°(C6H5OH, g) = −96.4 ± 0.6 kJ/mol (Cox, J. D. Pure Appl. Chem. 1961, 2, 125−128), is often used assuming high accuracy of the experimental value. In the present work a substantially less negative value of ΔfH298°(C6H5OH, g) = −91.8 ± 2.5 kJ/mol was calculated combining G4 theory with an isodesmic reaction approach...
April 21, 2016: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/27043241/treatment-of-cmv-infection-after-allogeneic-hematopoietic-stem-cell-transplantation
#10
REVIEW
Enrico Maffini, Luisa Giaccone, Moreno Festuccia, Lucia Brunello, Alessandro Busca, Benedetto Bruno
Despite a remarkable reduction in the past decades, cytomegalovirus (CMV) disease in allogeneic hematopoietic stem cell transplant (HSCT) recipients remains a feared complication, still associated with significant morbidity and mortality. Today, first line treatment of CMV infection/reactivation is still based on dated antiviral compounds Ganciclovir (GCV), Foscarnet (FOS) and Cidofovir (CDF) with their burdensome weight of side effects. Maribavir (MBV), Letermovir (LMV) and Brincidofovir (BDF) are three new promising anti-CMV drugs without myelosuppressive properties or renal toxic effects that are under investigation in randomized phase II and III trials...
June 2016: Expert Review of Hematology
https://www.readbyqxmd.com/read/26972692/detection-of-a-g-c-single-nucleotide-polymorphism-within-a-repetitive-dna-sequence-by-high-resolution-dna-melting
#11
Ulrike Schmidt, Johannes Hulkkonen, Jana Naue
In standard forensic DNA analysis, single base mutations within short tandem repeats (STR) mostly escape detection. In this study, high-resolution DNA melting (HRM) is compared to minisequencing and Sanger sequencing as to determine the most suitable method for detection of a G to C mutation within a repetitive DNA sequence, the STR system DXS10161. It shows an ATG/ATC polymorphism surrounded by a variable number of (TATC) and (ATCT) motifs. Neutral base changes like G:C to C:G result in very low differences in the melting temperature (T m) of the PCR amplicons...
September 2016: International Journal of Legal Medicine
https://www.readbyqxmd.com/read/26851143/measuring-the-capacity-for-auditory-system-plasticity-an-examination-of-performance-gains-during-initial-exposure-to-auditory-targeted-cognitive-training-in-schizophrenia
#12
Melissa Tarasenko, Veronica B Perez, Sean T Pianka, Sophia Vinogradov, David L Braff, Neal R Swerdlow, Gregory A Light
UNLABELLED: Auditory-Targeted Cognitive Training (ATCT), which aims to improve auditory information processing efficiency, has shown great promise for remediating cognitive deficits in schizophrenia (SZ). However, there is substantial heterogeneity in the degree of cognitive gains made during ATCT, and some patients show negligible benefit after completing therapeutic doses of training. Identifying individual differences that can be measured early in the course of ATCT and that predict subsequent cognitive benefits from the intervention is therefore important...
April 2016: Schizophrenia Research
https://www.readbyqxmd.com/read/26536014/genome-wide-analysis-of-microsatellite-markers-based-on-sequenced-database-in-chinese-spring-wheat-triticum-aestivum-l
#13
Bin Han, Changbiao Wang, Zhaohui Tang, Yongkang Ren, Yali Li, Dayong Zhang, Yanhui Dong, Xinghua Zhao
Microsatellites or simple sequence repeats (SSRs) are distributed across both prokaryotic and eukaryotic genomes and have been widely used for genetic studies and molecular marker-assisted breeding in crops. Though an ordered draft sequence of hexaploid bread wheat have been announced, the researches about systemic analysis of SSRs for wheat still have not been reported so far. In the present study, we identified 364,347 SSRs from among 10,603,760 sequences of the Chinese spring wheat (CSW) genome, which were present at a density of 36...
2015: PloS One
https://www.readbyqxmd.com/read/26524912/-prediction-of-promoter-motifs-in-virophages
#14
Chaowen Gong, Xuewen Zhou, Yingjie Pan, Yongjie Wang
Virophages have crucial roles in ecosystems and are the transport vectors of genetic materials. To shed light on regulation and control mechanisms in virophage--host systems as well as evolution between virophages and their hosts, the promoter motifs of virophages were predicted on the upstream regions of start codons using an analytical tool for prediction of promoter motifs: Multiple EM for Motif Elicitation. Seventeen potential promoter motifs were identified based on the E-value, location, number and length of promoters in genomes...
July 2015: Bing du Xue Bao, Chinese Journal of Virology
https://www.readbyqxmd.com/read/26447346/on-the-hcn-hnc-energy-difference
#15
Thanh L Nguyen, Joshua H Baraban, Branko Ruscic, John F Stanton
The value for the HCN → HNC 0 K isomerization energy has been investigated by combining state-of-the-art electronic structure methods with the Active Thermochemical Tables (ATcT) approach. The directly computed energy difference between HCN and HNC at the HEAT-456QP level of theory is 5236 ± 50 cm(-1). This is substantially lower (by ∼470 cm(-1) or ∼1.3 kcal/mol) than the recently proposed high-level multireference configuration interaction value of 5705 ± 20 cm(-1) of Barber et al. ( Mon. Not. R. Astron...
November 5, 2015: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/26171842/benchmarking-compound-methods-cbs-qb3-cbs-apno-g3-g4-w1bd-against-the-active-thermochemical-tables-formation-enthalpies-of-radicals
#16
Kieran P Somers, John M Simmie
The 298.15 K formation enthalpies of 38 radicals with molecular formula CxHyOz have been computed via the atomization procedure using the five title methods. The computed formation enthalpies are then benchmarked against the values recommended in the Active Thermochemical Tables (ATcT). The accuracy of the methods have been interpreted in terms of descriptive statistics, including the mean-signed error, mean-unsigned error, maximum average deviation, 2σ uncertainties, and 2×root-mean-square-deviations (2RMSD)...
August 20, 2015: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/25760799/active-thermochemical-tables-sequential-bond-dissociation-enthalpies-of-methane-ethane-and-methanol-and-the-related-thermochemistry
#17
Branko Ruscic
Active Thermochemical Tables (ATcT) thermochemistry for the sequential bond dissociations of methane, ethane, and methanol systems were obtained by analyzing and solving a very large thermochemical network (TN). Values for all possible C-H, C-C, C-O, and O-H bond dissociation enthalpies at 298.15 K (BDE298) and bond dissociation energies at 0 K (D0) are presented. The corresponding ATcT standard gas-phase enthalpies of formation of the resulting CHn, n = 4-0 species (methane, methyl, methylene, methylidyne, and carbon atom), C2Hn, n = 6-0 species (ethane, ethyl, ethylene, ethylidene, vinyl, ethylidyne, acetylene, vinylidene, ethynyl, and ethynylene), and COHn, n = 4-0 species (methanol, hydroxymethyl, methoxy, formaldehyde, hydroxymethylene, formyl, isoformyl, and carbon monoxide) are also presented...
July 16, 2015: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/25732248/tri-allelic-pattern-of-short-tandem-repeats-identifies-the-murderer-among-identical-twins-and-suggests-an-embryonic-mutational-origin
#18
Li-Feng Wang, Ying Yang, Xiao-Nan Zhang, Xiao-Liang Quan, Yuan-Ming Wu
Monozygotic twins can be co-identified by genotyping of short tandem repeats (STRs); however, for distinguishing them, STR genotyping is ineffective, especially in the case of murder. Here, a rarely occurring tri-allelic pattern in the vWA locus (16, 18, 19) was identified only in the DNA of one identical twin, which could help to exonerate the innocent twin in a murder charge. This mutation was defined as primary through genotyping of the family and could be detected in blood, buccal and semen samples from the individual; however, two alternative allele-balanced di-allelic patterns (16, 18 or 16, 19) were detected in hair root sheath cells...
May 2015: Forensic Science International. Genetics
https://www.readbyqxmd.com/read/25580800/benchmarking-compound-methods-cbs-qb3-cbs-apno-g3-g4-w1bd-against-the-active-thermochemical-tables-a-litmus-test-for-cost-effective-molecular-formation-enthalpies
#19
John M Simmie, Kieran P Somers
The theoretical atomization energies of some 45 CxHyOz molecules present in the Active Thermochemical Tables compilation and of particular interest to the combustion chemistry community have been computed using five composite model chemistries as titled. The species contain between 1-8 "heavy" atoms, and a few are conformationally diverse with up to nine conformers. The enthalpies of formation at 0 and 298.15 K are then derived via the atomization method and compared against the recommended values. In general, there is very good agreement between our averaged computed values and those in the ATcT; those for 1,3-cyclopentadiene exceptionally differ considerably, and we show from isodesmic reactions that the true value for 1,3-cyclopentadiene is closer to 134 kJ mol(-1) than the reported 101 kJ mol(-1)...
July 16, 2015: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/23834334/active-thermochemical-tables-water-and-water-dimer
#20
Branko Ruscic
A new partition function for water dimer in the temperature range 200-500 K was developed by exploiting the equations of state for real water vapor, liquid water, and ice, and demonstrated to be significantly more accurate than any proposed so far in the literature. The new partition function allows the Active Thermochemical Tables (ATcT) approach to be applied on the available experimental and theoretical data relating to water dimer thermochemistry, leading to accurate water dimer enthalpies of formation of -499...
November 21, 2013: Journal of Physical Chemistry. A
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