Follow-up of the Bacillus cereus emetic toxin production in penne pasta under household conditions using liquid chromatography coupled with mass spectrometry

Two outbreak-related Bacillus cereus emetic strains were investigated for their growth and cereulide production potential in penne pasta at 4, 8 and 25 °C during 7-day storage. Cereulide production was detected and quantified by LC-MS method (LOD of 1 ng/ml, LOQ of 5 ng/ml) and growth was determined by culture-based enumeration. Inoculated B. cereus strains (10(5) CFU/g) were able to reach counts of more than 10(8) CFU/g and cereulide production of about 500 ng/g already after 3 days of storage at 25 °C. Interestingly, a constant increase of the toxin was noticed during incubation at ambient temperature storage: the cereulide was continuously produced during the bacterial stationary growth phase reaching maximal amounts at the end of the experiment (7 days, concentration of about 1000 ng/g). Strictly respected cold chain temperature as 4 °C did not allow any detectable cereulide production for any of the two tested strains. At the limited temperature abuse of 8 °C, a detectable amount of cereulide was observed after two days for one of the strain (TIAC303) (相似文献   

Time-resolved strain and deformation measurement on the vibrating saxophone reed

Single-reed musical instruments, such as the saxophone, generate sound through a complex interplay between the mechanics of the reed and the hydrodynamic and acoustic pressure in the instrument mouthpiece. To understand this complex mechanism, experimental data are lacking. This paper presents full-field, time-resolved measurements of strain and displacement of a vibrating saxophone reed, measured under mimicked realistic playing conditions. It is found that strain along the length axis of the reed is mainly expansive, except in a small zone near the tip where it becomes compressive when the reed touches the front edge of the mouthpiece. At the instant in the vibration phase where the reed touches the mouthpiece, significant bending and compressive strain appear along the direction perpendicular to the reed axis. Strain magnitudes in both directions are similar, with absolute values of 0.1%. Full-field strain maps reveal subtle characteristics which are not revealed by displacement measurements. Bi-axial bending and strain may be an essential component in reed mechanics, which up till now has been fully neglected in modelling.     

Top-down kinetic modeling from power law to elementary steps using KASTER: A methane steam reforming case study

A top-down methodology for kinetic model construction including regression against experimental data is proposed using “KASTER.” As a case study, it is applied in the assessment of methane steam reforming (MSR) including water–gas shift (WGS) on a Ni catalyst at 923 K. The degree of detail in the reaction mechanism and the corresponding model is gradually enhanced, typically ranging from a simple power law to a microkinetic model. The reactor equations are solved transiently, preventing the numerical challenges encountered in the steady-state solution, particularly for microkinetic models. The microkinetic variant indicated that CH₄ dissociative adsorption and CO formation are kinetically relevant steps in MSR, while COOH formation is rate-determining in WGS. However, the model providing the best balance between detail accounted for and parameter significance corresponded to a Langmuir–Hinshelwood–Hougen–Watson (LHHW) mechanism accounting for dissociative adsorption, with CO formation and COOH formation as rate-determining steps for MSR and WGS, respectively.     

A solid‐like shell element allowing for arbitrary delaminations

In this contribution a new finite element is presented for the simulation of delamination growth in thin‐layered composite structures. The element is based on a solid‐like shell element: a volume element that can be used for very thin applications due to a higher‐order displacement field in the thickness direction. The delamination crack can occur at arbitrary locations and is incorporated in the element as a jump in the displacement field by using the partition of unity property of finite element shape functions. The kinematics of the element as well as the finite element formulation are described. The performance of the element is demonstrated by means of two examples. Copyright © 2003 John Wiley & Sons, Ltd.     

Clonidine and ketanserin both are effective treatment for postanesthetic shivering

BACKGROUND: Although meperidine is an effective treatment of postanesthetic shivering, its mechanism of action remains unknown. Investigation of other drugs might help clarify the mechanisms by which shivering can be controlled. Accordingly, we investigated the efficacy of clonidine, an alpha 2-adrenergic agonist, and ketanserin, a 5-hydroxytryptamine antagonist, in treating postanesthetic shivering. METHODS: First, 54 patients shivering after general anesthesia were allocated randomly to receive an intravenous bolus of saline, 150 micrograms clonidine, or 10 mg ketanserin. A second study explored the dose-dependence of clonidine. Forty shivering patients were given saline or clonidine, 37.5, 75, or 150 micrograms. RESULTS: The duration of shivering was significantly shorter in those given clonidine (2.1 +/- 0.9 min) than in the other two groups and shorter in the ketanserin group (4.3 +/- 0.9 min) than in the saline group (12.0 +/- 1.6 min). Clonidine and ketanserin significantly decreased systolic arterial blood pressure when compared to saline. Core rewarming was significantly slower in the clonidine group. In the second study, 37.5 micrograms clonidine was no more effective than saline. Two minutes after treatment, 150 micrograms obliterated shivering in all patients. Five minutes after treatment, all patients given 75 micrograms had stopped shivering. Systolic arterial pressure and heart rate decreased significantly in patients given 75 and 150 micrograms clonidine. CONCLUSIONS: Clonidine (150 micrograms) and ketanserin (10 mg) both are effective treatment for postanesthetic shivering. The effect of clonidine on shivering is dose-dependent: whereas 37.5 micrograms had no effect, 75 micrograms clonidine stopped shivering within 5 min.     

Fluorescent PCR and automated fragment analysis for the clinical application of preimplantation genetic diagnosis of myotonic dystrophy (Steinert''s disease)

Knowledge of the prevalence of congenital cytomegalovirus infection is necessary to evaluate the need for prevention. We performed a multicentre one-year study involving 11 neonatology divisions to ascertain the prevalence in Lombardy. Cytomegalovirus was isolated by culturing saliva samples from all babies born (n = 1268) of two 15-day sample periods and from 185 neonates with suspected congenital CMV based on clinical and laboratory findings and the history. The overall prevalence of congenital infection was 0.47% (6/1268) in the sample period group and 5% (9/185) in the second group. Clinical monitoring revealed sequelae in two of three children with symptomatic infection and no asymptomatic child at age two years. In a subgroup of 205 babies including 14 of the infected infants we also evaluated a test to detect cytomegalovirus DNA in the Guthrie cards obtained in neonatal screening for genetic and metabolic disorders. The test's sensitivity was 100% and specificity 98.5%, encouraging its use for early identification of infected neonates and for large epidemiological studies.     

An open book on Facebook? Examining the interdependence of adolescents’ privacy regulation strategies

Users of social network sites (SNSs) use three main strategies that help to manage the privacy of their profile information: (1) limiting the level of data revealed, (2) using privacy settings to exert control over data and (3) audience/friendship management by being restrictive about whom to accept as a ‘friend’. Extant research does not show whether these strategies operate as independent mechanisms or whether they are interdependent and work as a system. Given what offline privacy theorist Irwin Altman (1977 Altman, Irwin. 1977. “Privacy Regulation: Culturally Universal or Culturally Specific?” Journal of Social Issues 33 (3): 66–84. doi: 10.1111/j.1540-4560.1977.tb01883.x[Crossref], [Web of Science ®] , [Google Scholar]) designates as the multi-mechanic nature of privacy protection, we test a model in which we expect to find that the three discerned strategies are related to one another. Structural equation modelling analysis performed on the subsample (n?=?1564) of our study’s data – collected among 1743 adolescents by means of a paper-and-pencil survey – demonstrates that, in line with Altman’s vision of privacy protection, the three discerned strategies effectively operate as an interdependent system. In congruence with the hypotheses derived from extant research, we found that adolescents’ level of disclosure influences adolescents’ involvement in the two other discerned strategies: Adolescents with high levels of personal information disclosure share an increased tendency to have many friends on SNSs and a lower level of using privacy settings.     

Power saving through state retention in IGZO‐TFT AMOLED displays for wearable applications

We present a qHD (960 × 540 with three sub‐pixels) top‐emitting active‐matrix organic light‐emitting diode display with a 340‐ppi resolution using a self‐aligned IGZO thin‐film transistor backplane on polyimide foil with a humidity barrier. The back plane process flow is based on a seven‐layer photolithography process with a CD = 4 μm. We implement a 2T1C pixel engine and use a commercial source driver IC made for low‐temperature polycrystalline silicon. By using an IGZO thin‐film transistor and leveraging the extremely low off current, we can switch off the power to the source and gate driver while maintaining the image unchanged for several minutes. We demonstrate that, depending on the image content, low‐refresh operation yields reduction in power consumption of up to 50% compared with normal (continuous) operation. We show that with the further increase in resolution, the power saving through state retention will be even more significant.     

Modelling film formation and degradation of semi-transparent exterior wood coatings

Deposition and aggregation of small solid particles are encountered in many natural and industrial environments. These processes are of substantial significance for the development of a coating film on a wooden substrate. Formulating new coatings with improved performance and lower cost for exterior wooden joinery, mainly a trial-and-error approach, has a large influence on the initial film forming stage in a coating's life. Therefore modelling can supply insight in the particle–particle–substrate interaction. Two approaches are proposed. The first one uses a random point process to position the cluster centres and particles in a dry film. The second strategy starts with a random scattering of the particles in a wet film followed by Monte Carlo sampling and subsequently minimization of the total energy of the particle system. Surface roughness and gloss are calculated from the simulated surface structure. Next to these simulations, surface reconstruction of coated wood with confocal scanning laser microscopy (CSLM) is used to obtain surface roughness values and deduction of gloss applying the bidirectional reflection distribution function (BRDF) theory. As semi-transparent systems are the subject of gloss calculation on surfaces measured by CSLM and computer simulation, refractive index is estimated using an analytical solution of the reflectance and transmittance problem. Withal, coating and subsequent degradation simulation can become a valuable tool for screening purposes.