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At least 163 records · Page 9Linked to original sources
PubMed1999

Effect of refrigeration on shear bond strength of three dentin bonding systems.

PURPOSE: To determine whether use of dentin bonding agents directly from refrigerated storage would have adverse effects on their shear bond strength to dentin. MATERIALS AND METHODS: Resin-based composite cylinders were bonded to dentin on the ground occlusal surfaces of 60 extracted human molars using three different dentin bonding systems at 3.0 degrees C and 23.5 degrees C. The cylinders were then debonded using an Instron testing machine in compression mode at 0.5 mm/sec. The results were interpreted with t-test and Student-Newman-Keuls post hoc analysis. RESULTS: Scotchbond Multi-Purpose demonstrated significantly lower shear bond strengths at 23.5 degrees C (P < 0.05) than all other groups at both 3.0 degrees C and 23.5 degrees C. All-Bond 2 and Prime & Bond had higher shear bond strengths at refrigerated temperature, but the differences were insignificant in magnitude.

Bisphenol A-Glycidyl Methacrylate↗
PubMedDate not supplied

Movement of moisture in refrigerated cheese samples transferred to room temperature.

When cheese samples refrigerated at 4 degrees C in 120 mL plastic tubs were transferred to room temperature at 23 degrees C, moisture began to move from the warmer surface to the cooler interior; the difference after 1 h was 0.2-0.4%. Others had observed that moisture moved from the interior of warmer blocks of cheese to the cooler surface during cooling at the end of cheese manufacture. In loosely packed cheese prepared for analysis, part of the moisture movement may have been due to evaporation from the warmer surface and condensation on the cooler cheese. It is recommended that cheese be prepared for analysis immediately before weighing. Cheese samples that have been refrigerated, as in interlaboratory trials, should also be remixed or prepared again.

Cheese↗
PubMed2000

Food labeling, safe handling statements, labeling of shell eggs; refrigeration of shell eggs held for retail distribution. Food and Drug Administration, HHS. Final rule.

The Food and Drug Administration (FDA) is revising its food labeling regulations to require a safe handling statement on cartons of shell eggs that have not been treated to destroy Salmonella microorganisms. The agency also is requiring that, when held at retail establishments, shell eggs be stored and displayed under refrigeration at a temperature of 7.2 degrees C (45 degrees F) or less. FDA is taking these actions because of the number of outbreaks of foodborne illnesses and deaths caused by Salmonella Enteritidis (SE) that are associated with the consumption of shell eggs. These actions also respond, in part, to petitions from Rose Acres Farm, Inc., and the Center for Science in the Public Interest (CSPI). Safe handling statements will help consumers take measures to protect themselves from illness or deaths associated with consumption of shell eggs that have not been treated to destroy Salmonella (all serotypes). Refrigeration of shell eggs that have not been treated to destroy Salmonella will help prevent the growth of SE in shell eggs.

Consumer Product Safety↗
PubMed1975

Room temperature stability of drug products labeled for refrigerated storage.

The stability at room temperature of many pharmaceutical products labeled for storage under refrigeration is presented. The data were obtained through a survey of manufacturers. It is observed that many drug products labeled for refrigerated storage are stable at room temperature for extended periods.

Drug Stability↗
PubMedDate not supplied

Phenomenological theory on refrigeration effect of practical type-I superconductor.

In accordance with the phenomenological theory of thermodynamics, we discussed the Magnetocaloric effect of type-I superconductors, which are exposed to a varying magnetic field. It is concluded theoretically that the refrigeration effect is closely associated with demagnetization effect for practical specimens, which is different from the situation for ideal superconductor sample having no demagnetization effect. From the thermodynamic formulation of superconductivity, we deduced the integrating function of the thermal effect. By numerical calculation, we found a quantitative relation between the refrigeration effect and the demagnetizing factor which is determined by the shape of the sample.

Electric Conductivity↗
PubMed2001

[Growth kinetics and proteases production of Pseudomonas fluorescens in raw milk at refrigeration].

The general use of refrigeration of raw milk has contributed to maintenance of its quality, but has induced the selection of a psychotrophic bacteria which during its growth produces heat-resistant enzymes responsible, in part, for the deterioration of long-life products. Given the condition of the prolonged refrigeration of the milk before the process, it was necessary to determine the growth curves for bacteria at temperatures between 2 degrees C and 10 degrees C and the kinetics of production of proteases in raw fresh milk, inoculated with Pseudomonas fluorescens RV1O, using an automatic fermentation system, with minimal agitation under conditions of controlled temperature and pH. The results show a development over 10(5) ufc/mL in the cultures at 6 degrees, 8 degrees and 10 degrees C during the first 30 h and proteasic activities over 30 microM p-NA/2 h getting levels of de 80-180 microM p-NA/2 h over 50 h of cultivation. Only the cultures at 2 degrees C appeared stable with inferior cell counts and without inducing enzymatic activity. At 4 degrees C an intermediate situation occurs.

Animals↗
PubMed1975

Retention of albino and brown phenotypes of Histoplasma capsulatum by liquid nitrogren refrigeration.

Pathogenic differences between albino (A) and brown (B) phenotypes of Histoplasma capsulatum for experimental animals, and serological differences between A- and B- derived histoplasmins or yeast-phase antigens, necessitate the retention of these phenotypes in culture for diagnoses and epidemiologic studies. Selected strains of A and B types were frozen in liquid nitrogen (LN) and stored for 6-9 months in the vapor phase of a LN refrigerator (-165 degrees C). The strains were tested by using Berliner's method for differentiation of these two phenotypes. The results have proved that the LN refrigeration can be used for long-term conservation to prevent the conversion of B type into the A type in vitro.

Color↗
PubMed1987

Effects of refrigeration on daily microbial bioburden of hydrogel lenses.

Microbial bioburden of contact lenses was evaluated in connection with lens care by refrigeration. Subjects wore new hydrogel contact lenses for approximately 8 hours. The microbial bioburden initially and after an overnight refrigeration of the lens was evaluated with the use of viable counts on three different media. No major changes in viable counts were observed resulting from this method of storage. Scanning electron microscopy indicated the presence of foreign material on both new and worn lenses, presumed to be debris from lens manufacture and mucoid deposits from daily wear. Microbial colonization was not apparent and single bacterial cells could not be discerned on the micrographs.

Bacteria↗
PubMed1979

[German cockroaches (Blattella germanica) in a refrigerator].

German cockroaches (Blattella germanica) regularly occurred in a refrigerator of a hospital in Leipzig. Larvae of instars 1--6 of a population of high density but uneven spatial distribution infiltrated through the defective magnetic tape packing of the refrigerator door into an area maintaining +7...12 degrees C. In this way they utilised their temperature dependent ability to move almost down to the lower limit and gave a new example of the plasticity of their reactions. Behavioural and ecological aspects of the observations as well as hygienic consequences and prophylactic measures are discussed.

Animals↗
PubMedDate not supplied

Detection of Salmonella in dry foods using refrigerated pre-enrichment and enrichment broth cultures: summary of collaborative study.

A collaborative study was conducted to compare the productivity of refrigerated pre-enrichment and enrichment broth cultures with the U.S. Food and Drug Administration culture methods for detection of Salmonella. The refrigerated pre-enrichment and selective enrichment broth culture methods for detection of Salmonella in dry foods have been adopted first action by AOAC INTERNATIONAL.

Bacteriological Techniques↗
PubMed2002

Quantification of the refrigerants R22 and R134a in mixtures by means of different polymers and reflectometric interference spectroscopy.

The aim of this study was the quantification of vapors of the ozone-depleting refrigerant R22 in the presence of its most important substitute R134a, by the use of the reflectometric interference spectroscopy and polymers as sensitive layers. First, the sorption characteristic of different types of polymers exposed to the vapors of the two analytes was investigated. Then, binary mixtures of the two refrigerants were measured with an array set-up on the basis of six polymer sensors. The measurements were evaluated by the use of neural networks, whereby low limits of detection of 0.45 percentage volume (vol. %)for R22 and 1.45 vol. % for R134a could be established. Additionally, one polar polymer and one microporous polymer were selected for the measurements with a low-cost set-up. The quantification of R22 in the presence of R134a with this low-cost set-up was possible with a limit of detection of 0.44 vol. %, which would enable a fast and economical monitoring at recycling stations.

Air Pollutants↗
PubMed2002

Fresh cucumber flavor in refrigerated pickles: comparison of sensory and instrumental analysis.

The ability of nonacidified, refrigerated pickled cucumbers to produce the fresh cucumber flavor impact compounds (E,Z)-2,6-nonadienal and (E)-2-nonenal declined during storage. Production of these compounds decreased as the pH of refrigerated cucumbers was reduced. Despite the fact that the concentrations of (E,Z)-2,6-nonadienal and (E)-2-nonenal generated were over 10(5)-fold greater than the threshold levels, it was possible for a sensory panel to consistently detect differences in the intensity of fresh cucumber flavor, provided the pH difference between samples was 1 unit or greater. The presence of spices did not interfere with the ability of panelists to detect differences in fresh flavor intensity. There was a linear correlation between sensory scores and the amount of (E,Z)-2,6-nonadienal produced by cucumbers equilibrated at different pH levels.

Aldehydes↗
PubMed2003

Changes in volatile compounds of carrots (Daucus carota L.) during refrigerated and frozen storage.

Carrots (Daucus carota L.) of cv. Bolero and cv. Carlo were processed into shreds and stored for up to 4 months at -24 degrees C (frozen storage), or the roots were stored for up to 4 months at 1 degrees C (refrigerated storage) followed by processing into shreds. Volatiles from the carrot shreds were collected by dynamic headspace technique and analyzed by GC-FID, GC-MS, GC-MS/MS, and GC-O to determine the volatile composition and aroma active components of carrots stored under different temperature conditions. A total of 52 compounds were quantified, of which mono- and sesquiterpenes accounted for approximately 99% of the total volatile mass. Major volatile compounds were (-)-alpha-pinene, beta-myrcene, (-)-limonene, (+)-limonene, (+)-sabinene, gamma-terpinene, p-cymene, terpinolene, beta-caryophyllene, alpha-humulene, and (E)- and (Z)-gamma-bisabolene. A considerable increase in the concentration of mono- and sesquiterpenes was observed during refrigerated storage, whereas the concentration of terpenoids was around the same level during frozen storage. GC-O revealed that the major volatiles together with (+)-alpha-pinene, (-)-beta-pinene, (+)-beta-pinene, 6-methyl-5-hepten-2-one, (-)-beta-bisabolene, beta-ionone, and myristicin had an odor sensation, which included notes of "carrot top", "terpene-like", "green", "earthy", "fruity", "citrus-like", "spicy", "woody", and "sweet".

Chromatography, Gas↗
PubMed2006

Complex rare-earth tetrelides, RE5(SixGe(1-x))4: new materials for magnetic refrigeration and a superb playground for solid state chemistry.

A "giant magnetocaloric effect" discovered in 1997 for Gd5Si2Ge2 near room temperature has triggered optimism that environmentally-friendly, solid-state magnetic refrigeration may be viable to replace gas-compression technology in the near future. Gd5Si2Ge2 is one member of an extensive series of rare-earth compounds, RE5(SixGe(1-x))4. Due to the complexity of their structures and flexibility associated with chemical compositions, this series is an attractive "playground" to study the interrelationships among composition, structure, physical properties and chemical bonding. This tutorial review, which is directed toward students and researchers interested in structure-property relationships in solids, summarizes recent efforts concerning the synthesis, structure, physical properties, chemical bonding and chemical modifications of RE5(SixGe(1-x))4. A brief history of refrigerants, to present certain motivating factors for this research effort, as well as a brief overview of the magnetocaloric effect serves to introduce this review.

Journal Article↗
PubMed2006

Detection of refrigerator-associated 60 Hz alternating current as ventricular fibrillation by an implantable defibrillator.

This report describes a patient with an implantable defibrillator who suffered an inappropriate defibrillation shock upon retrieving some food items from his inadequately earthed refrigerator. Noise typical of electrical interference can be observed in the stored electrogram of the episode. The patient was instructed to earth his home appliances, but he decided to avoid his refrigerator altogether, and has had no subsequent shocks.

Aged↗
PubMedDate not supplied

Six-month stability of bevacizumab (Avastin) binding to vascular endothelial growth factor after withdrawal into a syringe and refrigeration or freezing.

PURPOSE: To determine the change in anti-vascular endothelial growth factor (VEGF) activity of bevacizumab (Avastin, Genentech, Inc., San Francisco, CA) after refrigeration or freezing. METHODS: Samples of bevacizumab were drawn up from new vials into plastic tuberculin syringes and refrigerated at 4 degrees C for 1 week, 3 weeks, 1 month, 3 months, and 6 months. The vials and syringes were stored at 4 degrees C, and the syringes were capped with a needle. One syringe was frozen at -10 degrees C. The bevacizumab concentration was measured, via its binding to VEGF-165. RESULTS: The percentage of degradation of bevacizumab in the previously pierced vials stored at 4 degrees C compared with that in the unpierced vial was 9.6% at 3 months and 12.7% at 6 months. The bevacizumab drawn into the syringe and stored at 4 degrees C was degraded by 1.6% at 1 week, 0% at 3 weeks, 8.8% at 3 months, and 15.9% at 6 months. The bevacizumab frozen in a syringe at -10 degrees C was degraded by 12.0% at 6 months. CONCLUSION: The anti-VEGF activity of bevacizumab may degrade minimally over time, with storage.

Angiogenesis Inhibitors↗
PubMed2002

The optimal stack spacing for thermoacoustic refrigeration.

The characteristic pore dimension in the stack is an important parameter in the design of thermoacoustic refrigerators. A quantitative experimental investigation into the effect of the pore dimensions on the performance of thermoacoustic devices is reported. Parallel-plate stacks with a plate spacing varying between 0.15 and 0.7 mm are manufactured and measured. The performance measurements show that a plate spacing in the stack of 0.25 mm (2.5 deltak) is optimum for the cooling power. A spacing of 0.4 mm (4 deltak) leads to the lowest temperature. The optimum spacing for the performance is about 0.3 mm (3 deltak). It is concluded that a plate spacing in the stack of about three times the penetration depth should be optimal (3 deltak) for thermoacoustic refrigeration.

Journal Article↗