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PubMed1974

[New diagrams for quick calculation of refrigerating machines (author's transl)].

The present edition is a re-elaboration and an extension of a previous one and takes into account the data meanwhile brought up to date--concerning the characteristics of saturated vapours--as well as the opportuneness of an easier consultation. In fact, by introducing logarithmic scales and by an appropriate choice of the logarithmic modulus, it has been possible to summarize the characteristics of each fluid in one diagram only, whereas, in the first edition, the extension of the metric scales of the abcissas imposed to divide each diagram in two parts. Besides, more units have been introduced, namely: m3/kcal, m3/kj and ft3/Btu for volumes; oF and oC degrees for temperatures. These new diagrams have heen developed for the following refrigerant fluids: R 11, R 12, R 13, R 13 B1, R 22, R 114, R 502, NH3 and CH3Cl. Known the temperature before the throttling device, the evaporating temperature and the one of the eventual superheating, they enable to promptly calculate the volume of the refrigerant in the gaseous phase, both as dry saturated vapour and superheated vapour; besides, they allow the quick calculation of the speed of the fluid inside thepiping system, the performance of the compressor under different working conditions and with different refrigerants, and so on. A number of practical examples illustrate even more clearly what stated about quickness and possibilities of calculation.

Refrigeration↗
PubMed1977

Effect of refrigeration on bactericidal activity of four preserved multiple-dose injectable drug products.

The influence of refrigeration on the bactericidal capability of preservative systems in multiple-dose injectable drug products was studied. Commercially available multiple-dose injectable drug products containing preservatives--atropine/phenol, lidocaine/methylparaben, cyanocobalamin/benzyl alcohol and diphenhydramine/benzethonium chloride--were divided into two groups, one to be maintained under refrigeration (5C) and the other to be maintained at room temperature (25C). In separate tests the multiple-dose vials (MDVs) were individually inoculated with the following organisms: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Serratia marcescens, and cultured to establish bacterial concentrations at 0, 1, 2, 4, 8 and 24 hours. Bacteria in the preservative systems tested remained viable significantly longer under refrigeration. (Data for diphenhydramine/benzethonium were not obtainable with the methodology used.) It is recommended that sterile medications maintained in preserved MDVs be stored at romm temperature after initial use (i.e., after exposure to possible contamination) unless drug stability considerations dictate otherwise.

Alcohols↗
PubMed1989

An ergonomics approach to refrigerator design for the elderly person.

The objective was to determine a set of refrigerator design guidelines for independent living elderly women. The study was conducted with a refrigerator mockup with interchangeable internal features. Twelve elderly women participated, both in a standing and seated (wheelchair) position. The participants were videotaped as they simulated use of shelves and drawer, and they rated these components and their positions for acceptability of reach, visibility of contents, and personal preference. Participants then used a variety of mockup items to configure the refrigerator to their own preferred design. These were then analysed and synthesised into three 'consensus' designs combining the features of most of the others.

Journal Article↗
PubMed2005

A comparative study on lipid peroxidation, activities of antioxidant enzymes and viability of cattle and buffalo bull spermatozoa during storage at refrigeration temperature.

A comparative study was conducted to monitor the activities of some antioxidant enzymes, lipid peroxidation and viability of cattle and buffalo bull spermatozoa during storage of semen at refrigeration temperature over a period of 72 h. Semen samples, collected from six cross bred cattle bulls (group I) and six Murrah buffalo bulls (group II), were diluted in egg-yolk-citrate and the spermatozoa were separated from seminal plasma by centrifugation at 4 degrees C in a refrigerated centrifuge. The malondialdehyde (MDA) production in group I increased from 1.17+/-0.29 at 0 h to 7.50+/-0.52 nmol/10(8)spermatozoa after 72 h of storage while in group II it increased from 1.99+/-0.26 to 8.70+/-0.10 nmol/10(8)spermatozoa in the same period. However, buffalo bull spermatozoa had a significantly higher (p<0.05) lipid peroxidation at 0 h as well as at 12, 24 and 48 h (p<0.01) periods. The activities of antioxidant enzymes viz. SOD, GPx and G6PD in both the groups showed a similar pattern of change i.e. the activities declined successively in spermatozoa and increased in the seminal plasma. However, the activities of these three enzymes remained significantly higher in the cattle bull spermatozoa than that in buffalo bull spermatozoa. Amount of MDA produced in spermatozoa of both the groups was negatively correlated while SOD, GPx and G6PD activities in spermatozoa were positively correlated to the motility and viability of spermatozoa. Sperm motility as well as viability was significantly less (p<0.05) in group II than that in group I. SOD, GPx and G6PD activities in spermatozoa of both the groups were negatively correlated to lipid peroxidation of spermatozoa cell membrane. The results showed that the less activities of antioxidant enzymes in buffalo bull spermatozoa was due to higher lipid peroxidation that indicated that they were more prone to oxidative stress as compared to cattle bull spermatozoa when stored at refrigeration temperature.

Animals↗
PubMed2000

Flow cytometric evaluation of antibiotic effects on viability and mitochondrial function of refrigerated spermatozoa of Nile tilapia.

Improved techniques for storage and evaluation of fish sperm would enhance breeding programs around the world. The goal of this study was to test the effect of antibiotics on refrigerated sperm from Nile tilapia (Oreochromis niloticus) by use of flow cytometry with 2 dual-staining protocols for objective assessment of sperm quality. Concentrations of 1 x 10(9). sperm/mL were suspended in Ringer's buffer at 318 mOsmol/kg (pH 8.0). The fluorescent stains Sybr 14 (10 microM), propidium iodide (2.4 mM), and rhodamine 123 (0.13 microM) were used to assess cell viability and mitochondrial function. Three concentrations of ampicillin, gentamicin, and an antibiotic/antimycotic solution were added to fresh spermatozoa. Motility estimates and flow cytometry measurements were made daily during 7 d of refrigerated storage (4 degrees C). The highest concentrations of gentamicin and antibiotic/antimycotic and all 3 concentrations of ampicillin significantly reduced sperm viability. The highest of each of the 3 antibiotic concentrations significantly reduced mitochondrial function. This study demonstrates that objective sperm quality assessments can be made using flow cytometry and that addition of antibiotics at appropriate concentrations can lengthen refrigerated storage time for tilapia spermatozoa. With minor modifications, these protocols can be adapted for use with sperm from other species and with other tissue types.

Animals↗
PubMed2003

Refrigerated dough syruping in relation to the arabinoxylan population.

Refrigerated doughs develop syruping upon prolonged storage. To assess the role of arabinoxylans (AX), in this phenomenon, the evolution of the AX population and syruping in refrigerated doughs during storage were studied. When doughs were kept at 6 degrees C for up to 34 days of storage, dough syruping increased from 0% (fresh dough) to 22% of dough weight, reaching a plateau after 16 days of storage. High-performance size exclusion chromatography and gas-liquid chromatography showed hydrolysis of water-unextractable AX in the refrigerated dough, resulting in increased levels of solubilized AX in the first 2 days of storage. Longer storage resulted in further degradation of solubilized and water-extractable AX. Increased syruping was accompanied by a decrease in farinograph dough consistency. The results support the hypothesis that loss of water-holding capacity due to degradation of AX by endogenous xylanases is responsible for dough syruping.

Bread↗
PubMed2000

Interaction of temperature, humidity, driver preferences, and refrigerant type on air conditioning compressor usage.

Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity. Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted.

Air Conditioning↗
PubMed2002

Quantum refrigeration cycles using spin-1/2 systems as the working substance.

The cycle model of a quantum refrigerator composed of two isothermal and two isomagnetic field processes is established. The working substance in the cycle consists of many noninteracting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semigroup approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate, and power input, are given. Especially, the case at high temperatures is analyzed in detail. The results obtained are further generalized and discussed, so that they may be directly used to describe the performance of the quantum refrigerator using spin-J systems as the working substance. Finally, the optimum characteristics of the quantum Carnot refrigerator are derived simply.

Journal Article↗
PubMed1985

Laboratory evaluation of skin refrigerants used in dermabrasion.

Six skin refrigerants were evaluated for maximum cooling temperature. The temperatures produced correlated well with the chemical components and also the gelatin freeze-thaw times. Freon 114 and Freon 114-ethyl chloride mixtures are time-tested, safe skin refrigerants. Some of the newer skin refrigerants are pure sources of Freon 12 or mixtures of Freon 12 and Freon 11. These newer, colder products have the potential to damage the skin and represent a hazard to successful dermabrasion.

Chlorofluorocarbons, Methane↗
PubMed1989

Stability of famotidine in minibags refrigerated and/or frozen in total parenteral nutrition solutions.

The use of histamine2-receptor antagonists could be beneficial in critically ill patients for protection against stress-induced gastrointestinal bleeding. Famotidine, similar to cimetidine and ranitidine, is stable when mixed in dextrose 5% injection and NaC1 0.9% injection at a concentration of 200 micrograms/mL and stored in polyvinyl chloride bags at 4 degrees C for 14 days or when frozen for 28 days and subsequently refrigerated for 14 days. Furthermore, famotidine, also like cimetidine and ranitidine, is stable when added to most common total parenteral nutrition (TPN) solutions. Famotidine in concentrations of 20 mg/L and 40 mg/L is stable in crystalline amino acid solutions (20 g/L and 42.5 g/L) when refrigerated for 24 hours, then held at room temperature for 24 hours, at room temperature for 48 hours, or refrigerated for seven days. The concentration of amino acids in the TPN solutions containing 42.5 g/L also is not affected by the addition of famotidine 40 mg/L when stored under conditions similar to those stated above for 48 hours. TPN solutions remain clear and free of turbidity.

Amino Acids↗
PubMedDate not supplied

[Evaluation of rapid urease test stored in refrigerator].

UNLABELLED: The rapid urease test is an accurate and cheap method, which results are readily available, and broadly used for routine Helicobacter pylori infection diagnosis. AIM: The evaluation of rapid urease test stored in refrigerator at 4 degrees C (SRUT) compared to regular rapid urease test. PATIENTS AND METHOD: Endoscopic biopsies were obtained from gastric antrum in 104 consecutive patients. Diagnosis of Helicobacter pylori infection was accomplished by rapid urease test, histology and rapid urease test stored (kept in refrigerator by a period ranging from 1 to 8 days). RESULTS: Infection was considered present if both rapid urease test and histology were positive. Helicobacter pylori was present in 45/104 patients (42%). Rapid urease test stored had specificity comparable to rapid urease test (93%), with sensitivity of 88%. CONCLUSION: We concluded that rapid urease test can be stored in refrigerator for up to 1 week, without loss of clinical applicability, and that can make the test even easier to use for routine Helicobacter pylori tests in a busy endoscopy unit.

Adolescent↗
PubMed2006

Effects of frozen and refrigerated storage on organic acid profiles of goat milk plain soft and Monterey Jack cheeses.

The effects of 6 mo of freezing and refrigeration on organic acid profiles of 2 types of goat milk cheese [plain soft (PS) and Monterey Jack (MJ)] were studied in comparison with those of a nonfrozen control (NFC). Three lots of commercial PS cheeses were purchased, and 3 lots of MJ cheeses were manufactured at the University dairy plant. Each lot of the 2 types of cheeses was subdivided into 4 equal portions, and one subsample of each cheese was immediately stored at 4 degrees C as the NFC for 0, 14, and 28 d. The other 3 were immediately frozen (-20 degrees C) for 0, 3, and 6 mo (0MF, 3MF, and 6MF) and subsequently thawed the next day at 4 degrees C. The samples were then stored at 4 degrees C for 0, 14, and 28 d. Organic acids were quantified using an HPLC. The PS had no pyruvic acid, and MJ contained no isotartaric acid; however, several unknown large peaks appeared between propionic and butyric acids. Differences in organic acid contents between PS and MJ cheeses were significant for all acids except citric and lactic acid. Lot effect was significant for most of the known acids, indicating that variations existed in milk composition and manufacturing parameters. Effects of storage treatments (NFC, 0MF, 3MF, and 6MF) were significant for most organic acids, except for orotic and a few unidentified acids. Aging at 4 degrees C for 4 wk had little influence on all organic acids, except butyric acid. Concentrations of butyric, lactic, propionic, tartaric, and uric acids were significantly elevated as the frozen storage period advanced. At the initial stage, there were no differences in pH and acid degree values between NFC and frozen-stored groups of both cheeses. However, acid degree values gradually increased as the refrigerated storage extended up to 4 wk, indicating that lipolysis increased as the refrigeration storage at 4 degrees C advanced. Although levels of several organic acids were changed in the goat cheeses, the prolonged frozen storage, up to 6 mo, was apparently feasible for extending storage.

Acetic Acid↗
PubMed1995

The effect of refrigerated and frozen storage on populations of mesophilic and coliform bacteria on fresh broiler chicken carcasses.

Experiments were conducted to determine whether lots of broiler chicken carcasses analyzed at Day 0 or subjected to various refrigeration or freezing temperatures could be microbiologically differentiated using impedance microbiological methods. Sixty ready-to-cook broiler chicken carcasses were collected from a processing facility and used in each of three replicate trials. For each trial, 10 carcasses each were: sampled immediately (Day 0 control), sampled after holding at 3 C for 13 d (Refrigerated control), sampled after holding at 0 C for 12 d and tempering at 3 C for 24 h (Refrigerated 0), sampled after holding at -3.9 C for 12 d and tempering at 3 C for 24 h (Frozen -3.9), sampled after holding at -7.8 C for 12 d and tempering at 3 C for 24 h (Frozen -7.8), and sampled after holding at -27.0 C for 12 d and tempering at 3 C for 24 h (Frozen -27). Carcasses were sampled using a whole carcass rinse procedure. Mesophilic impedance detection times (MDT) and coliform impedance detection times (CDT) at 42 C were conducted in duplicate on each carcass rinse. Lots of carcasses held at 0 C or below had significantly fewer mesophiles than those held at 3 C. The MDT would be suitable for distinguishing carcasses held at 0 C or below from those held at 3 C. Using CDT, lots of carcasses frozen at -7.8 or -27.0 C could be distinguished from lots analyzed at Day 0 or held at 0 or 3 C. Using CDT, lots of carcasses frozen at -3.9 could not be separated from those held at 3 C, but could be distinguished from those held at 0 C. Monitoring coliforms using impedance would be useful for identifying lots of carcasses subjected to temperatures of -7.8 C or below but would not be suitable for determining freezing temperature.

Animals↗
PubMed1999

Antagonistic action of Lactobacillus lactis toward Salmonella spp. and Escherichia coli O157:H7 during growth and refrigerated storage.

Cells of Lactobacillus lactis were added to trypticase soy broth that contained cells of Escherichia coli O157:H7 or cells of Salmonella spp. in order to determine if L. lactis inhibited the pathogens. The inhibition of all pathogens was examined during growth at 37 degrees C for 24 h. Inhibition of Salmonella spp. was also examined at refrigeration temperatures (6 degrees C) for 5 days. One strain each of E. coli O157:H7, Salmonella Typhimurium, and Salmonella Enteritidis was examined. E. coli was enumerated on violet red bile agar, and Salmonella spp. were enumerated on brilliant green agar. In all experiments at 37 degrees C, the L. lactis completely inhibited all pathogens, producing numbers that were not detectable after 24 h of incubation. There were significant (P > 0.05) increases in numbers of the pathogens in the control samples containing no L. lactis. There were significant (P < 0.05) declines in the pH of both control and L. lactis inoculated samples. There was a significantly (P < 0.05) larger decline in the pH of samples inoculated with L.lactis. Interaction studies with pH-neutralized broth indicated that acid production by L lactis was primarily responsible for the inhibition. Numbers of Salmonella spp. incubated at 6 degrees C did not decline significantly (P > 0.05) for control or inoculated samples, which suggests that this strain of L. lactis does not inhibit Salmonella spp. at refrigeration temperatures. Additionally, there were no significant (P > 0.05) changes in pH or in numbers of L. lactis during refrigerated storage.

Cold Temperature↗
PubMedDate not supplied

Influence of different intravenous infusion sets on temperature of refrigerated parenteral nutrition solutions.

We measured the temperature of 10 previously refrigerated parenteral-nutrition solutions (PN solutions) at the end of a standard intravenous-infusion set (IIS) (Intrafix, 145 cm long), an IIS with a mechanical device to control the flow of the solution (Dial-a-Flow, 226 cm long), and an IIS to be used with a volumetric infusion pump (Infusomat, 259 cm long). The temperature of the PN solution just after taking it out of the refrigerator was 6.0 +/- 0.8 degrees C (mean +/- SD), and that of the room was 24.2 +/- 0.7 degrees C. We recorded the temperature again at the end of the IIS after draining it freely, i.e., until there was no air inside the set (time 0), after 5, 10, and 15 min of infusion at 100 ml/h. After 15 min, the temperature at the end of the Intrafix set did not statistically differ (P less than 0.05) from room temperature. With Dial-a-Flow, the temperature of the solution was not statistically different from room temperature at any time. Finally, with Infusomat, the temperature was statistically different from that of the room for the first 5 min. We thus conclude that refrigerated PN solution can be administered to patients without having to warm it whenever an IIS is longer than 145 cm and flow not exceeding 100 ml/h is used. Adverse reactions sometimes observed in patients at the beginning of the administration of PN solution cannot, in our opinion, be attributed to the low temperature of the solution.

Cold Temperature↗
PubMedDate not supplied

[Temperature of refrigerated parenteral nutrition solutions at the end of 2 infusion systems].

It is common practice to let parenteral nutrition bags that are kept refrigerated stand at room temperature before administration. In this study the temperature of the mixtures administration. In this study the temperature of the mixtures flowing at the end of a conventional system (Intrafix 145 cm long) and at the end of a flow-control system (Dial-a-flow 226 cm long) were measured. Mixture temperatures within the parenteral nutrition bag were recorded upon removal from the refrigerator, at the end of the infusion system after purging the system with the fastest flow rate possible (time 0), and at 5, 10, and 15 minutes, after sustaining continuous flow at 100 cc/hour. The conventional system showed no statistically significant differences (P less than 0.05) between room temperature (23.7 +/- 0.5) and mixture temperature at the end of the infusion line at 15 minutes of infusion (23.0 +/- 0.9). The Dial-a-flow system showed no statistically significant differences between room temperature (24.5 +/- 0.9) and mixture temperatures at the end of the system (time 0: 23.7 +/- 2.2; 5 minutes, 24.1 +/- 0.8; 10 minutes, 24.3 +/- 0.7; 15 minutes, 24.4 +/- 0.7) (p less than 0.05). Therefore, the results indicate that refrigerated parenteral nutrition bags can be administered directly to the patient without waiting for the mixture to warm up, anytime the length of the infusion system is over 145 cm. Occasional reactions observed at the onset of parenteral nutrition therapy cannot be attributed to low mixture temperature, and as such, other reasons must be searched for.

Cold Temperature↗
PubMed1986

Stability of ranitidine admixtures frozen and refrigerated in minibags.

The stability of ranitidine hydrochloride stored frozen and refrigerated in polyvinyl chloride minibags was studied. Ranitidine hydrochloride was added to either 5% dextrose injection or 0.9% sodium chloride injection to yield concentrations of 0.5, 1.0, and 2.0 mg/mL. In phase 1 of the study, admixtures containing ranitidine hydrochloride 1 mg/mL were stored at 4 degrees C for 10 days. In phase 2, solutions were frozen for 30 days at -30 degrees C and were later refrigerated for 14 days. Ranitidine concentration was tested using a stability-indicating high-performance liquid chromatographic assay at time zero and at intervals during storage. Sterility tests were performed on some samples, and various admixtures were visually inspected and tested for pH. At least 90% of the initial concentration of ranitidine remained in all solutions at all storage conditions. No visual changes or changes in pH or sterility were observed. Ranitidine hydrochloride in concentrations of 0.5, 1.0, and 2.0 mg/mL in 5% dextrose injection or 0.9% sodium chloride injection may be stored in polyvinyl chloride minibags frozen for 30 days followed by refrigeration for an additional 14 days.

Drug Combinations↗
PubMedDate not supplied

Thermodilution cardiac output determinations: a comparison of iced and refrigerated injectate temperatures in patients after cardiac surgery.

OBJECTIVE: To compare cardiac output determinations with two temperatures of injectate: iced (0 degrees to 6 degrees C) and refrigerated (10 degrees to 16 degrees C) in adult patients after cardiac surgery. DESIGN: A quasi-experimental study design was used. The dependent variable was cardiac output. The independent variable was injectate temperature. Each patient served as his or her own control. SETTING: Intensive care unit at a 500-bed urban teaching hospital in Western Canada. SAMPLE: A convenience sample of 40 male and female patients admitted to the intensive care unit after myocardial revascularization and/or valvular surgery between March and August 1991. All patients experienced surgery with the normothermic technique. METHOD: Each subject had cardiac output determinations performed within 12 hours of surgery with both 10 ml refrigerated and 10 ml iced injectate. The capped syringe technique was used. DATA ANALYSIS: A paired t test was performed to determine statistically significant differences between the two sets of measurements. Regression analysis was used to determine strength of agreement between the two techniques. Clinical significance was examined by a difference in mean cardiac output greater than 15% resulting in an alteration in medical therapy. RESULTS: There were no statistically or clinically significant differences between the two methods of cardiac output determinations. Regression analysis showed very good agreement (r = 0.965, p < 0.0001). Clinically, when the two cardiac outputs were reported to the surgeon, medical therapy was not altered based on differences. CONCLUSIONS: The use of 10 ml of refrigerated injectate provides reproducible cardiac output results as compared with iced injectate in normothermic patients after cardiac surgery. Further investigation is required to generalize these results to other patient populations and to determine the reproducibility with a lower volume of injectate.

Adult↗