Ultrafast Mapping of Electronic and Nuclear Structure in the Photo Dissociation of Nitrogen Dioxide.

We investigate the photoinduced dissociation reaction of NO → NO + O upon electronic excitation of the X̃A (D) to the ÃB (D) state by femtosecond X-ray absorption spectroscopy at the nitrogen K-edge. We obtain key insight into the chemical bond breaking event and its associated electronic structural dynamics. Calculations of the photoinduced reaction allow to assign the transient absorption features at time scales of 10-50 fs to wave packet motions in the excited D and ground D states, followed by the formation of the NO photoproduct with a 255 ± 23 fs time constant.

Isolation and Enumeration of the Bacillus cereus Group Using a Chromogenic Substrate that Targets Phosphatidylcholine Phospholipase C Activity.

The Bacillus cereus group is comprised of diverse yet closely related species that are ubiquitous in nature. These Gram-positive, spore-forming bacteria are commonly isolated as potential pathogens in environmental and food samples, and they are also beneficially used in industrial applications such as probiotics or agricultural pesticides. Although phylogenetic and genomic analyses identified eight formally recognized species within the Bacillus cereus group, only five members are currently acknowledged using standardized isolation procedures.

Distinguishing Organomagnesium Species in the Grignard Addition to Ketones with X-Ray Spectroscopy.

The addition of Grignard reagents to ketones is a well-established textbook reaction. However, a comprehensive understanding of its mechanism has only recently begun to emerge. X-ray spectroscopy, because of its high selectivity and sensitivity, is the ideal tool for distinguishing between an ensemble of competing pathways.

Comparison of Two Culture-Based Detection Systems for the Isolation of Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii in Raw Ground Poultry.

Arcobacters are emerging pathogens that have been underestimated due to a lack of a standardized isolation method. The aim of this research was to evaluate the ability to isolate Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii using two Arcobacter-specific culture detection systems: (i) the Houf broth and modified charcoal cefoperazone deoxycholate agar supplemented with cefoperazone, amphotericin B, and teicoplanin (HB/mCCDA+CAT), and (ii) the Nguyen-Restaino-Juárez Arcobacter enrichment broth and chromogenic agar (NRJ-B/M). Both detection systems were evaluated for productivity ratio, sensitivity, and specificity.

NRJ Media as the Gold-Standard -Specific Detection System: Applications in Poultry Testing.

species are ubiquitous emerging pathogens with an impact that has been underestimated due to limitations in isolation and detection methods. Our group recently developed the novel NRJ -detection system, with major improvements in specificity and selectivity compared to other culture-based methods. In this work, the NRJ detection system was evaluated using retail whole broiler chicken carcass.

Probing nonadiabatic dynamics with attosecond pulse trains and soft x-ray Raman spectroscopy.

Linear off-resonant x-ray Raman techniques are capable of detecting the ultrafast electronic coherences generated when a photoexcited wave packet passes through a conical intersection. A hybrid femtosecond or attosecond probe pulse is employed to excite the system and stimulate the emission of the signal photon, where both fields are components of a hybrid pulse scheme. In this paper, we investigate how attosecond pulse trains, as provided by high-harmonic generation processes, perform as probe pulses in the framework of this spectroscopic technique, instead of single Gaussian pulses.

A New Method for Detection of Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii Using a Novel Chromogenic Agar.

Abstract: Arcobacter species are gram-negative rods that have been implicated in food- and waterborne illness. Although various cultural isolation methods have been proposed, the current procedures are unable to fully suppress the growth of background microbiota present in food samples, which inhibits Arcobacter isolation. The purpose of this study was to develop a selective enrichment broth and chromogenic plating medium to detect three Arcobacter species that have been recognized as emerging foodborne pathogens: Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii.

Enantioselective oxidation of sulfides catalyzed by titanium complexes of 1,2-diarylethane-1,2-diols: effect of the aryl substitution.

The effects of the substitution on the aryl moiety on the asymmetric oxidation of sulfides mediated by Ti-complexes of chiral 1,2-diarylethane-1,2-diols were investigated. The substitution of the aryl ring of the diol with both EWG and EDG substituents generally decreased the enantioselectivity with respect to the use of unsubstituted 1,2-diphenylethane-1,2-diol (1a). Only in the presence of 1,2-di(4-t-butyl)phenyl-1,2-diol (1g) were higher ee's obtained with aryl methyl and aryl benzyl sulfides affording ee's up to 90 and 99%, respectively.

A selective chromogenic agar that distinguishes Bacillus anthracis from Bacillus cereus and Bacillus thuringiensis.

A selective and differential plating medium, R & F anthracis chromogenic agar (ACA), has been developed for isolating and identifying presumptive colonies of Bacillus anthracis. ACA contains the chromogenic substrate 5-bromo-4-chloro-3-indoxyl-choline phosphate that upon hydrolysis yields teal (blue green) colonies indicating the presence of phosphatidylcholine-specific phospholipase C (PC-PLC) activity. Among seven Bacillus species tested on ACA, only members of the Bacillus cereus group (B.

A chromogenic plating medium for the isolation and identification of Enterobacter sakazakii from foods, food ingredients, and environmental sources.

A chromogenic agar, R&F Enterobacter sakazakii chromogenic plating medium (ESPM), was developed for isolating presumptive colonies of E. sakazakii from foods and environmental sources. ESPM contains two chromogenic substrates (5-bromo-4-chloro-3-indoxyl-alpha-D-glucopyranoside and 5-bromo-4-chloro-3-indoxyl-beta-D-cellobioside), three sugars (sorbitol, D-arabitol, and adonitol), a pH indicator, and inhibitors (bile salts, vancomycin, and cefsulodin), which all contribute to its selectivity and differential properties.

Efficacy of enrichment broths in the recovery of freeze-injured Escherichia coli O157:H7 in inoculated ground beef by PCR.

Escherichia coli O157:H7 strains ATCC 35150 and ATCC 43894 and five pooled isolates from beef and pork freeze injured at -25 degrees C in beef infusion were used to inoculate ground beef. Samples (25 g each) were added to 225 ml of buffered peptone water with vancomycin, cefsulodin, and cefixime (BPW-VCC), 225 ml of modified EC broth plus novobiocin (mEC+n), and 225 ml of R&F enrichment broth (R&F-EB) and aerobically incubated at 41 to 42 degrees C. After 6, 7, 8, and 24 h of incubation, levels of E.

Comparison of the Reveal 20-hour method and the BAM culture method for the detection of Escherichia coli O157:H7 in selected foods and environmental swabs: collaborative study.

Four different food types along with environmental swabs were analyzed by the Reveal for E. coli O157:H7 test (Reveal) and the Bacteriological Analytical Manual (BAM) culture method for the presence of Escherichia coli O157:H7. Twenty-seven laboratories representing academia and private industry in the United States and Canada participated.

Reveal 8-Hour Test System for detection of Escherichia coli O157:H7 in raw ground beef, raw beef cubes, and iceberg lettuce rinse: collaborative study.

Five different food types were analyzed by the Reveal for E. coli O157:H7 8-Hour Test System (Reveal 8) and either the U.S.

Efficacy of chromocult coliform agar for coliform and Escherichia coil detection in foods.

Chromocult coliform agar (CCA) was compared with Petrifilm Escherichia coli count plate (PEC) for identifying coliforms and E. coli in a variety of meat products. Products examined included 45 raw beef samples, 12 sausage emulsion samples, 11 samples of meat-based ready-to-eat appetizers, and 8 pork trimming samples.

A chromogenic plating medium for isolating Escherichia coli O157:H7 from beef.

There was no significant difference (P > 0.05) in the percentages of Escherichia coli O157:H7 cells recovered on BCM O157:H7 (+) agar (69.7%) and MacConkey sorbitol agar containing 5-bromo-4-chloro-3-indoxyl-beta-D-glucuronic acid (MSA-BCIG) (76.

Isolation and detection of Listeria monocytogenes using fluorogenic and chromogenic substrates for phosphatidylinositol-specific phospholipase C.

The BCM Listeria monocytogenes detection system (LMDS) consists of a selective preenrichment broth (LMPEB), selective enrichment broth (LMSEB), selective/differential plating medium (LMPM), and identification on a confirmatory plating medium (LMCM). The efficacy of the BCM LMDS was determined using pure cultures and naturally and artificially contaminated environmental sponges. The BCM LMPEB allowed the growth of Listeria and resuscitation of heat-injured L.

A 5-h screening and 24-h confirmation procedure for detecting Escherichia coli O157:H7 in beef using direct epifluorescent microscopy and immunomagnetic separation.

An antibody-direct epifluorescent filter technique (Ab-DEFT) detected 100% of the raw ground beef samples inoculated with Escherichia coli O157:H7 cells (0.15 cells g-1) and incubated in a prewarmed, modified buffered peptone water (mBPW) non-selective enrichment broth for 5 h at 42 degrees C in an orbital shaking water bath (200 rev min-1). Over 50% of the microscopic fields viewed were positive (1-10 fluorescent cells field-1) in the Ab-DEFT.

Antibody-Direct Epifluorescent Filter Technique and Immunomagnetic Separation for 10-h Screening and 24-h Confirmation of Escherichia coli O157:H7 in Beef.

Rapid screening of beef for the presence of Escherichia coli O157:H7 was shown to be feasible using a 10-h enrichment in modified buffered peptone water and the antibody-direct epifluorescent filter technique (Ab-DEFT). The Ab-DEFT involved membrane filtration, fluorescent antibody staining and epifluorescence microscopy and was accomplished in less than 1 h. The procedure allowed detection of the pathogen artificially inoculated into beef patties at 0.

Antimicrobial Effectiveness of Potassium Sorbate and Sodium Benzoate against Zygosaccharomyces bailii in a Salsa Mayonnaise.

The antimicrobial effectiveness of sodium benzoate and potassium sorbate (0.05, 0.10, 0.

Efficacy of ozonated water against various food-related microorganisms.

The antimicrobial effects of ozonated water in a recirculating concurrent reactor were evaluated against four gram-positive and four gram-negative bacteria, two yeasts, and spores of Aspergillus niger. More than 5 log units each of Salmonella typhimurium and Escherichia coli cells were killed instantaneously in ozonated water with or without addition of 20 ppm of soluble starch (SS). In ozonated water, death rates among the gram-negative bacteria--S.

Antimicrobial Efficacy of a New Organic Acid Anionic Surfactant Against Various Bacterial Strains.

The surface sanitizing properties of a buffered organic acid anionic surfactant (BOAAS) was compared with six traditional sanitizers (organic chlorine - 100 ppm, two iodophors - 25 ppm, peroxyacetic acid - 483 ppm, acid anionic - 230 ppm, and a quaternary ammonium compound - 150 ppm) in its ability to reduce Staphylococcus aureus on an inoculated Formica surface. In the absence of organic material, the traditional sanitizers were not significantly different (P > 0.05) from water in reducing S.

Comparison of β-Glucuronidase and Indole-Based Direct Plating Methods for Enumerating Escherichia coli in Artificially Inoculated Ground Meats.

Peptone tergitol glucuronide (PTG) agar containing 4-methylumbelliferyl-β-D glucuronide (MUG) (for β-glucuronidase activity), the Holbrook, Anderson, Baird-Parker (HABP) method (for detecting indole production), and the standard 3-tube most probable number (MPN) method were compared with plate count agar (PCA) for enumerating three strains of unstressed Escherichia coli artificially inoculated into ground beef and chicken at 1-6 × 10 cells/g. No significant difference (P>0.05) was determined between PTG agar and PCA in the recovery of E.

Use of the Chromogenic Substrate 5-Bromo-4-Chloro-3-Indolyl-B-D-Glucuronide (X-GLUC) for Enumerating Escherichia coli in 24 H from Ground Beef.

A 24-h direct plating method for Escherichia coli using the chromogenic substrate 5-bromo-4-chloro-3-indolyl-B-D-glucuronide (X-GLUC) incorporated into a Peptone-tergitol agar base (PTX) was compared with the standard 3-tube Most Probable Number (MPN) method on 50 naturally contaminated ground beef samples. A paired-comparisons t-test showed no significant difference between the two methods. A positive linear correlation between the two methods was observed over the entire range of values.