Assessment of hygienic quality of surfaces in retail food service establishments based on microbial counts and real-time detection of ATP

Clean food contact surfaces are important in reducing the likelihood of foodborne disease transmission. The goal of this study was to assess and compare baseline cleanliness of food contact and environmental surfaces in retail food establishments by using ATP bioluminescence (ATP-B), visual assessment, and surface contact plates. Four hundred eighty-nine surface samples were collected from three food service establishments at the University of Minnesota-Twin Cities (Minneapolis) and analyzed for either ATP (252) or total aerobic plate count bacteria (237). ATP levels ranged from a minimum of 4 relative light units (RLU; 0.60 log RLU) on a clean slicer to a maximum of 506,618 RLU (5.77 log RLU) on a dirty cutting board. The overall mean was 1,950 RLU (3.29 log RLU). Cutting boards had the highest ATP levels (mean, 5,495 RLU or 3.74 log RLU; median, 6,761 RLU or 3.83 log RLU). Of the 128 samples judged visually clean at the time of sampling, 70.3 % failed ATP-B testing. Sixty-one (26 % ) of the 237 total aerobic plate count samples yielded counts of over 125 CFU/50 cm(2) (failed), and of those that failed, 40 % were assessed as visually clean before sampling. The highest average counts in CFU/50 cm(2) were found on slicers (104) and cutting boards (87). The results of this study suggest that the current practice of evaluating food contact surface cleanliness by sight and touch to meet regulatory requirements might be inadequate. ATP-B testing may be an efficient tool to facilitate creation, implementation, and validation of more effective food contact surface cleaning in food establishments.     

The growth and morphology of core/shell heterostructured conical carbon fibers

Core/shell heterostructured conical carbon fibers with silicon-based cores and graphitic carbon sheaths have been grown on silicon carbide (SiC) surfaces exposed to the combustion of methane. The conical carbon fibers (CCFs), which taper from a circular base to a point, appear to form by two simultaneous growth processes, axial tip-growth and radial fiber thickening. Radial fiber thickening results from pyrolytic carbon deposition from gas-phase hydrocarbons. Oxidation of SiC surfaces is proposed to produce gas-phase silicon oxides, which feed axial tip-growth and install the silicon-based core. The unusual morphology of the CCFs, including bending, branching, curving and tapering, is proposed to result from the action and interplay of these two simultaneous processes.     

台北艺术中心

正为什么过去百年间最令人兴奋的剧场盛事总是发生在正规场所之外?建筑如何才能超越自身卑微的命运,摆脱那种限制各种可能的宿命?近年来,世界各地的演艺中心数目渐增,但不知何故,这些演艺中心似乎达成一种共识,呈现出雷同的空间组合:一座约2 000席的大型演艺厅和一个1 500席的中型剧院,再加上一个黑盒子剧场。标志性的外形掩饰以典型19世纪做法为基础的     

Efficient stabilization of Cu+ ions in phosphate glasses via reduction of Cu2+ by Sn2+ during ambient atmosphere melting

Glasses containing substantial amounts of well-dispersed luminescent Cu⁺ ions are attractive materials for applications in solid-state lighting, photonic waveguides, and solar cells. Thus far, coming across a simple yet effective method for the preparation of such has remained elusive given the instability of Cu⁺ relative to Cu²⁺, especially for syntheses carried out under the oxidizing air atmosphere. In this work, high concentrations of monovalent copper ions are shown to be successfully incorporated in a high-solubility phosphate glass matrix by a simple melt-quench method. The traditional Cu²⁺ spectrophotometric analysis commonly utilized for liquid solutions is proposed herein for the solid-state material to estimate the reduction efficiency of Cu²⁺ during the material preparation process. Reproducibly, the use of relatively large quantities of copper(II) oxide with equal amounts of reducing agent tin(II) oxide (up to 20 mol%), together with the use of sucrose to assist as antioxidant during melting in air atmosphere, yields high-reduction efficiencies estimated at 98 %. Along with the optical absorption analysis, photoluminescence spectroscopy is employed in evaluating the emission properties of the glasses in connection to the Cu⁺ ions. Further, solid-state ³¹P nuclear magnetic resonance spectroscopy reveals the structural features of the glasses that support the remarkable stabilization of the Cu⁺ ions.     

Photoluminescence in Nd-doped V2O5

Based on the melt-quenching method, V₂O₅ was doped with Nd³⁺ ions. Photoluminescent properties due to electronic transitions of Nd³⁺ were found. In spite of the used method in the fabrication of this material, which consisted in a thermal shock from 1073 to 100 K, all the characterization techniques indicated that V₂O₅ has a crystalline orthorhombic phase and is acting as a host matrix for the Nd³⁺ ions. For instance, in the X-ray diffraction patterns, only well-defined peaks associated to V₂O₅ were detected. By Raman spectroscopy, vibrational modes related to V₂O₅ were observed. An E _g  = 2.15 eV was determined from the optical absorption spectrum for this doped material. Scanning electron microscopy images recorded on a fresh fracture show that this material is formed by lamellar plates. The elemental semi quantitative analysis indicates that the doping level with Nd³⁺ was of the order of 2.0 ± 0.2 at.%. Dark conductivity measurements yielded values in the 10^?6–10^?12 (Ω cm)^?1 range. Finally, by micro photoluminescence spectroscopy, the {⁴F_5/2, ⁴F_3/2} → ⁴I_9/2 electronic transitions related to Nd³⁺ ions were observed.     

Clinical significance of the isolation of rapidly growing mycobacteria

BACKGROUND: To assess the clinical significance of the isolates of rapid-growing mycobacteria in a Universitary hospital from Madrid (Spain). PATIENTS AND METHODS: Review of medical records from patients with isolates of rapid-growing mycobacteria identified between 1979 and 1996 in the Microbiology department of the Fundación Jiménèz Díaz (Madrid, Spain). RESULTS: Rapid-growing mycobacteria were isolated from 28 patients during the study period (13 M. chelonae, 10 M. fortuitum, 2 M. mucogenicum, 1 M. marinum, 1 M. smegmatis and 1 M. flavascens). Clinical records of 26 patients were reviewed, being the isolate significative in 10 cases (5 soft tissue infections, 2 peritonitis in patients undergoing Continuous Ambulatory Peritoneal Dialysis [CAPD], 1 urinary tract infection, 1 osteomyelitis and 1 catheter-related soft-tissue infection). No patient was HIV+. All infections cured except 2 of them (the urinary tract infection and the osteomyelitis). Catheter withdrawal was needed in 3 cases (peritonitis in CAPD and catheter-related soft-tissue infection), apart from proper antimicrobial therapy. CONCLUSION: The most frequent rapid-growing mycobacteria isolated were those of the M. fortuitum complex. In our experience, isolation of rapid-growing mycobacteria from skin and soft-tissue samples was usually clinically significant, while isolates from respiratory tract, gut and blood cultures are always nonsignificant.     

Prevalence of chronic urticaria following the ingestion of food additives in a third tier hospital

We studied 40 patients with the clinical diagnostic of chronic urticaria from January to June, 1995 and excluded 4 patients who did not fulfilled the entry criteria. 29 women and 7 men with age from 4 to 62 years old. We performed a basic clinics history and the oral challenge tests (PRO) included Tartrazine (Ta), Sodium Metabisulfite (MS), Potasium Metabisulfite (MP) and Sodium Bisulfite (BS) in consecutive days with increasing doses unless an adverse reactions appear. Other tests included Skin Prick tests for food (PC), complete blood counts, coprology and immunology tests (IgE, IgA, IgM, IgG, C3, C4, Cel LE and ANA) and paranasal sinus X Ray. 63.8% (23/36) had positive PRO. 47.2% (17/36) positives to Ta,, 36.1% (13/36) to MS, 33.3% (12/36) to BS and 30.5% (11/36) to MP. 72.2% (26/36) had positive PC to one or more foods, 65.3% (17/26) besides had positive PRO. 41.1% (7/17) of the patients who had positive PRO and positive PC to foods had sinusitis. One patient (0.23%) had palpebral angioedema with PRO. The prevalence was 3.1%. Ta was the additive that cause more reactivity. It is possible to find reactivity to one or more additives in a patient with chronic urticaria.     

Investigation of diode geometry and metal line pattern for robust ESD protection applications

The effect of different diode geometries and metal patterns on the failure current It2 is investigated experimentally. The devices considered are N+/P well LOCOS diodes having different lengths, widths, finger numbers, and metal connections. The results provide useful insights into optimizing the diode for robust electrostatic discharge (ESD) protection applications.     

Identification of adulterants added to beeswax: Estimation of detectable minimum percentages

The minimum percentages of adulteration of pure beeswax from Apis mellifera with three paraffins of different melting points and with cow tallow, stearic acid and carnauba wax that can be detected by gas chromatography with flame ionization detection were established. The concentrations of 93 endogenous beeswax compounds such as aliphatic hydrocarbons, olefins, acids, monoesters, alcohols and hydroxyacids were measured in relation to an internal standard (octadecyl octadecanoate) in mixtures of beeswax with the six adulterants; the variation of the concentrations of the compounds with the adulteration percentage was also studied. Percentages higher than 1–4% of each adulterant can be detected in the mixtures. The added adulterant can be identified by the non‐endogenous beeswax compounds observed in the chromatogram; the changes in the concentrations of some beeswax compounds are also useful to corroborate the identification.