Comparison of Roka Atlas® System Performance and Health Canada Reference Method for Listeria Detection From Plastic, Sealed Concrete, and Stainless-Steel Surface Samples.

Background: There is a high demand in the food industry and in public health for rapid automated methods capable of high-volume sample processing.

Objective: In an unpaired study, Roka Atlas® System performance was compared with Health Canada reference method MFHPB-30 for Listeria spp. (LSP Roka assay) and Listeria monocytogenes (LmG2 Roka Assay) detection on plastic (PL), sealed concrete (SC), and stainless-steel (SS) surfaces (45 samples each per candidate or reference method).

kinetics of the CHNH + NO reaction: formation of nitramines and -alkyl nitroxides.

This study provides a detailed understanding of how the reaction between CHNH, one of the primary products of the CHNH + OH/Cl reactions, and NO occurs in the atmosphere since the reaction is expected to be a dominant sink for the tropospheric CHNH radical. First, we focus on the reaction of the aminyl radical CHNH with NO, complementing the known reaction between CHNH and NO, to provide the overall picture of the CHNH + NO system. The reaction was meticulously examined across the extended range of temperature (298-2000 K) and pressure (0.

Mechanistic and Kinetic Insights into OH-Initiated Atmospheric Oxidation of Hymexazol: A Computational Study.

Hymexazol is a volatile fungicide widely used in agriculture, causing its abundance in the atmosphere; thus, its atmospheric fate and conversion are of great importance when assessing its environmental impacts. Herein, we report a theoretical kinetic mechanism for the oxidation of hymexazol by OH radicals, as well as the subsequent reactions of its main products with O and then with NO by using the Rice-Ramsperger-Kassel-Marcus-based Master equation kinetic model on the potential energy surface explored at the ROCBS-QB3//M06-2X/aug-cc-pVTZ level. The predicted total rate constants (, ) for the reaction between hymexazol and OH radicals show excellent agreement with scarcely available experimental values (e.

OH-initiated oxidation of vinyl butyrate: insights.

The widespread use of vinyl butyrate (CHCHOC(O)CHCHCH or VB) in the polymer industry and daily-life materials inevitably results in its emission into the atmosphere. Therefore, understanding the mechanism and kinetics of the VB conversion is critical for evaluating its fate and environmental impacts. Herein, we theoretically investigate the chemical transformation of VB initiated by OH radicals in the atmosphere using the stochastic Rice-Ramsperger-Kassel-Marcus (RRKM)-based master equation kinetic model on the potential energy surface explored at the M06-2X/aug-cc-pVTZ level of theory.

Metal complexes of benzimidazole-derived as potential anti-cancer agents: synthesis, characterization, combined experimental and computational studies.

In this study, a series of 14 Cu (II), Zn (II), Ni (II) and Ag (I) complexes containing bis-benzimidazole derivatives were successfully designed and synthesized from 2-(1-benzimidazole-2-yl)-phenol derivatives and corresponding metal salt solutions. The compound structures were identified by FT-IR, H-NMR, powder X-ray diffraction and ESI-MS analyses, and the presence of the metal in the complexes was confirmed by ultraviolet-visible spectroscopy and ICP optical emission spectrometry. Electronic structure calculations were also carried out to describe the detailed structures in addition to the electronic absorption spectra of the ligands.

On The Radical Scavenging and DNA Repairing Activities by Natural Oxygenated Diterpenoids: Theoretical Insights.

Diterpenoids are abundant and important compounds in Euphorbia species owing to their structural diversity; therefore, in this study, we investigate the modern-concept antioxidant activities, including free-radical scavenging and oxidative DNA damage repairing, of highly oxygenated diterpenoids originating from the aerial part of . Four compounds with structural types of -abietane, containing a fused furan ring in their structures, including euphelionolide A (), euphelionolide D (), euphelionolide I (), and euphelionolide L () are selected. First, the radical-scavenging activity of these compounds was evaluated with two typical radicals HOO and HO in water and pentyl ethanoate (PEA, to mimic lipid environment) via three main mechanisms, namely, hydrogen atom transfer (HAT), radical adduct formation (RAF), and single electron transfer.

Ab Initio Kinetics of Initial Thermal Pyrolysis of Isopropyl Propionate: A Revisited Study.

This work reports a detailed mechanism of the initial thermal pyrolysis of isopropyl propionate, (CHC(=O)OCH(CH)), an important biodiesel additive/surrogate, for a wide range of = 500-2000 K and = 7.6-76 000 Torr. The detailed kinetic behaviors of the title reaction on the potential energy surface constructed at the CBS-QB3 level were investigated using the RRKM-based master equation (RRKM-ME) rate model, including hindered internal rotation (HIR) and tunneling corrections.

New Mechanistic Insights into Atmospheric Oxidation of Aniline Initiated by OH Radicals.

This study theoretically reports the comprehensive kinetic mechanism of the aniline + OH reaction in the range of 200-2000 K and 0.76-7600 Torr. The temperature- and pressure-dependent behaviors, including time-resolved species profiles and rate coefficients, were studied within the stochastic RRKM-based master equation framework with the reaction energy profile, together with molecular properties of the species involved, characterized at the M06-2X/aug-cc-pVTZ level.

Multiple dehydrogenation of fluorene cation and neutral fluorene using the statistical molecular fragmentation model.

The statistical molecular fragmentation (SMF) model was used to analyze the 306 fragmentation channels (containing 611 different species) that result from the fluorene (C13H10+) cation losing up to three hydrogen atoms (neutral radicals and/or a proton). Breakdown curves from such analysis permit one to extract experimentally inaccessible information about the fragmentation of the fluorene cation, such as the locations of the lost hydrogen atoms (or proton), yields of the neutral fragments, electronic states of the residues, and quantification of very low probability channels that would be difficult to detect. Charge localization during the fragmentation pathways was studied to provide a qualitative understanding of the fragmentation process.

Validation of the AtlasTMCampylobacter Detection Assay: AOAC Performance Tested MethodSM 032101.

Background: Campylobacter spp. are a major causal agent for diarrheal illness in humans. Detection of Campylobacter spp.

Microbiologique Microfilm™ EBEc - a Rapid Method for the Simultaneous Enumeration of Enterobacteriaceae and Escherichia coli.

Background: The Enterobacteriaceae and generic Escherichia coli are routinely enumerated in foods as part of product release criteria, or in the case of swabs, for environmental monitoring.

Objective: Microbiologique Microfilm™ EBEc is intended to provide a rapid and easy-to-use method for simultaneous enumeration of Enterobacteriaceae and E. coli on foods and environmental surfaces.

Detailed kinetics of hydrogen abstraction from -decalin by OH radicals: the role of hindered internal rotation treatment.

In this study, the detailed kinetic mechanism of the trans-decalin + OH reaction is firstly investigated for a wide range of conditions (i.e., T = 200-2000 K & P = 0.

Two-Year Clinical Outcomes of Combined Phacoemulsification, Goniosynechialysis, and Excisional Goniotomy For Angle-Closure Glaucoma.

Purpose: The aim of this study was to describe changes in intraocular pressure (IOP) and IOP medications after phacoemulsification with Kahook Dual Blade-assisted goniosynechialysis and excisional goniotomy in eyes with angle-closure glaucoma and cataract.

Design: Retrospective case series.

Methods: Data were collected retrospectively through 24 months of follow-up in 42 eyes of 24 subjects.

Ab initio kinetic mechanism of OH-initiated atmospheric oxidation of pyrrole.

The comprehensive kinetic mechanism of the OH-initiated gas-phase oxidation of pyrrole is first theoretically reported in a broad range of conditions (T = 200-2000 K &P = 1-7600 Torr). On the potential energy surface constructed at the M06-2X/aug-cc-pVTZ level, the temperature- and pressure-dependent behaviors of the title reaction were characterized using the stochastic Rice-Ramsperger-Kassel-Marcus based Master Equation (RRKM-ME) rate model. The corrections of the hindered internal rotation and quantum tunneling treatments were included.

Ab initio dynamics of hydrogen abstraction from NH by OH radicals: an RRKM-based master equation study.

The detailed reaction mechanism of the NH + OH reaction is comprehensively reported for a wide range of conditions (i.e., T = 200-3000 K & P = 1-7600 Torr) using the CCSD(T)/CBS//M06-2X/6-311++G(3df,2p) level and the master equation/Rice-Ramsperger-Kassel-Marcus (ME/RRKM) rate model, which includes corrections of the hindered internal rotor (HIR) and tunneling treatments.

Twelve-month outcomes of excisional goniotomy using the Kahook Dual Blade in eyes with angle-closure glaucoma.

Purpose: To characterize clinical outcomes following Kahook Dual Blade (KDB)-assisted goniosynechialysis and excisional goniotomy combined with phacoemulsification in eyes with angle-closure glaucoma and cataract.

Setting: Two clinical practices.

Methods: In this retrospective analysis of existing health records, data were collected from 42 eyes of 24 subjects from preoperative, operative, and postoperative encounters through 12 months of follow-up.

Comment on "Atmospheric oxidation reactions of imidazole initiated by hydroxyl radicals: kinetics and mechanism of reactions and atmospheric implications" by Safaei et al., Phys. Chem. Chem. Phys., 2019, 21, 8445.

In this short communication, we resolve the discrepancy in chemical kinetics between the recent theoretical work by Safaei et al. (Phys. Chem.

Ab initio kinetics of the CH + NH reaction: a revisited study.

This work provides a rigorous detailed kinetic study on the CH + NH reaction in a wide range of conditions (T = 250-2000 K & P = 1-76000 Torr). In particular, the composite method W1U was used to construct the potential energy surface on which the kinetic behaviors were characterized within the state-of-the-art master equation/Rice-Ramsperger-Kassel-Marcus (ME/RRKM) framework. Corrections of the hindered internal rotation (HIR) treatment and quantum tunneling effect were included.

Application of Sample6 DETECT™ HT/L Kit for the Detection of Listeria in Mixed Leafy Greens.

Background: Early and accurate detection of Listeria in foods is vital. Current methods require 24 h enrichment for detection.

Objective: This study aimed to demonstrate enhanced early detection of Listeria in mixed leafy greens using Sample6 DETECT™ HT/L, a phage-based detection system.

Kahook Dual Blade Excisional Goniotomy and Goniosynechialysis Combined With Phacoemulsification for Angle-closure Glaucoma: 6-Month Results.

Purpose: The purpose of this study was to characterize reductions in intraocular pressure (IOP) and the need for IOP-lowering medications following phacoemulsification combined with Kahook Dual Blade-assisted goniosynechialysis and excisional goniotomy in eyes with angle-closure glaucoma and cataract.

Methods: In this retrospective, interventional case series, preoperative, operative, and postoperative data were collected through 6 months of follow-up from 42 eyes of 24 subjects. Outcomes included mean IOP reduction, reduction in IOP-lowering medications, and the proportion of patients achieving IOP reduction ≥20%, IOP≤18 mm Hg, and reduction of ≥1 medication.

mHDFS-HoF: A generalized multilevel homodesmotic fragment-separation reaction based program for heat-of-formation calculation for acyclic hydrocarbons.

Based on our modified classification of elemental species, a framework for automatic generation of multilevel Homodesmotic fragment-separation (mHDFS) reactions for chemical species was proposed. Combined the mHDFS framework with a database of heat of formation (HoF) and the calculated electronic structure data for the elemental mHD species, the mHDFS-HoF program was constructed in C/C++ language to calculate heat of formation for a species of interest on-the-fly. Using the electronic structure data calculated at CBS-QB3 level of theory for the elemental mHD species, applications and robustness of the code were discussed with several acyclic hydrocarbon systems including neutral and radical species.

Application of an Environmental Phage-Based Assay (Sample6 Detect HT/L) for the Detection of spp. in Ice Cream.

Dairy products are common sources of outbreaks, and early detection of the pathogen is critical to prevent outbreaks of illnesses and financial losses for dairy producers. This study aimed to evaluate Sample6 Detect HT/L for effective detection of and in ice cream. Performance of the Sample6 DETECT HT/L was compared with U.

Detailed kinetics of tetrafluoroethene ozonolysis.

The C2F4 + O3 reaction plays an important role in the oxidation process of perfluoroalkenes in the atmosphere. The detailed reaction mechanism was explored using the accurate electronic structure method, CCSD(T)/CBS//B3LYP/aug-cc-pVTZ. The 1,3-cycloaddition of O3 with C2F4 to form the primary ozonide was found to be the rate-determining step of the oxidation process with a small barrier (i.

Low Temperature Oxidation Kinetics of Biodiesel Molecules: Rate Rules for Concerted HO Elimination from Alkyl Ester Peroxy Radicals.

In an attempt to construct detailed kinetic mechanisms for biodiesel fuels on the fly, high-pressure rate rules for the concerted HO elimination reaction class were derived using a comprehensive training reaction set of more than 60 reactions involving different alkyl methyl/ethyl ester peroxy radicals (RCOOR')-OO. Using the composite electronic structure method CBS-QB3 in combination with classical statistical mechanics and the transition state theory (TST) rate model, high-pressure rate constants for the reactions in the training set as well as thermodynamic properties for the species involved were calculated. The corrections from Eckart tunneling and hindered internal rotation (HIR) treatments were also included in the calculations.

On-the-fly kinetics of hydrogen abstraction from polycyclic aromatic hydrocarbons by methyl/ethyl radicals.

This work provides a rigorous procedure, within the framework of the Reaction Class Transition State Theory (RC-TST) and the Structure-Activity Relationship (SAR), for predicting reliable thermal rate constants on-the-fly for hydrogen abstraction reactions by methyl/ethyl radicals from Polycyclic Aromatic Hydrocarbons (PAHs) in a temperature range of 300-3000 K. All necessary RC-TST parameters were derived from ab initio calculations for a representative set of 36 reactions on which different error analyses and comparisons with available literature data were carried out. In addition to the good agreement between the RC-TST rate constants and the literature data, the detailed error analyses show that RC-TST/SAR, utilizing either the Linear Energy Relationship (LER) where only the reaction energy is needed or Barrier Height Grouping (BHG) where no additional data is needed, can predict the thermal rate constants for any reaction in the title reaction class with an average systematic error of less than 50% when compared to the explicit rate calculations.