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At least 793 records · Page 44Linked to original sources
PubMed2001

Temperature-induced expression of phb genes in Escherichia coli and the effect of temperature patterns on the production of poly-3-hydroxybutyrate.

The plasmid pNDTM2 was constructed to contain the p(R)-p(L) promoter and the phbC, A, and B genes which code for PHB synthase, beta-ketothiolase, and acetoacetyl-CoA reductase, respectively. This plasmid was transformed into Escherichia coli XL1-Blue. The effect of several thermal induction patterns on the production of poly-3-hydroxybutyric acid (PHB) was investigated based on fermentor experiments. Based on the experimental results with different induction patterns, it was found that the temperature should be controlled at 34 degrees C during the initial 10 h of cultivation to promote cell growth, and then it should be increased to 40 degrees C for induction. Then the temperature should be lowered to 37 degrees C after 5 h to relieve the effect of the heat shock.

Journal Article↗
PubMed1994

[Rapid temperature measurement by calculating the final temperature within the response time].

For the early detection of an epidemic among animals in mass production, rapid information about the temperature of the animals is important. The response time of conventional thermometers is too long to permit rapid measurement. For adequate accuracy the measuring time required is about five times the response time. Using a microcomputer and regression computation, measurement of the final temperature can be effected within the period of a single response time. In addition, several thousand data can be stored for evaluation at a later date.

Animal Husbandry↗
PubMed2003

[Combustion temperature measurement of solid propellant and the effect of organic compound on combustion temperature].

The FTIR emission spectra in the spectral range of 4,500-300 cm-1 for the solid propellants were measured by a remote sensing FTIR system. The P-branch of fine structure of HCl fundamental band lying at 3.46 microns was used for precise combustion temperature measurement of the solid propellant. The effect of the organic compound in the solid propellant on the combustion temperature was discussed.

English Abstract↗
PubMedDate not supplied

Supralingual temperatures compared to tympanic and rectal temperatures.

OBJECTIVE: To evaluate the validity, reliability, sensitivity, and specificity of the PaciTemp supralingual digital pacifier thermometer as compared to the Thermoscan Instant tympanic and glass-mercury rectal thermometers. METHOD: Eighty-one children under the age of 2 years had temperatures taken sequentially at three body sites: supralingual, tympanic, and rectal. Corrections were calculated between the readings of the three types of thermometers. Percentage of agreement was done to examine sensitivity and specificity. RESULTS: Using the glass-mercury measurement as the standard, both the supralingual and tympanic measurements showed an overall specificity of 62.8% and sensitivity of 63.3%. Correlation between rectal and supralingual was 0.62, and correlation between rectal and tympanic was 0.71. CONCLUSIONS: The Paci-Temp provides temperature readings that are similar to the tympanic method as compared to the rectal method. Further research on at-home thermometers is needed.

Child, Preschool↗
PubMed1976

Stereospecific actions of 2,5-dimethoxy-4-methylamphetamine (DOM) on colonic temperature in the rat at various ambient temperatures.

The R(-) and S(+)-isomers of 2,5-dimethoxy-4-methylamphetamine (DOM) produce a dose-dependent hypothermia in rats kept in the cold (6 degrees C). 2 This hypothermia was linearly dependent upon ambient temperature and the R(-)-isomer was considerably more potent than the S(+)-isomer. 3 A statistically significant tachyphylaxis was observed when R(-)-DOM was administered on two successive days. The response seven days after the second injection was similar to that on the first day of injection. 4 The hypothermia induced by R(-) and S(+)-DOM was antagonized by methysergide but not by p-chlorophenylalanine (PCPA) or pimozide. Methysergide, PCPA or pimozide alone did not elicit hypothermia at the doses used. The results indicate that R(-) and S(+)-DOM act at post-synaptic 5-hydroxytryptamine receptors.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1971

Growth temperatures and temperature characteristics of Aeromonas.

Six of the 13 Aeromonas hydrophila, 1 of 10 A. shigelloides, and none of 10 A. salmonicida were found to be psychrophiles. All of the rest of the strains were mesophiles. The mu values (temperature characteristics) could not be used to distinguish psychrophiles from mesophiles.

Aeromonas↗
PubMed2004

Imparting temperature sensitivity and attenuation in ferrets to A/Puerto Rico/8/34 influenza virus by transferring the genetic signature for temperature sensitivity from cold-adapted A/Ann Arbor/6/60.

The four temperature-sensitive (ts) loci identified in the PB1 and PB2 gene segments of cold-adapted A/Ann Arbor/6/60 influenza virus, the master donor virus for influenza A virus (MDV-A) FluMist vaccines, were introduced into a divergent A/Puerto Rico/8/34 influenza virus strain. Recombinant A/Puerto Rico/8/34 virus with these four introduced ts loci exhibited both ts and att phenotypes similar to those of MDV-A, which could be used as a donor virus for manufacturing large quantities of inactivated influenza virus vaccine against potential pandemic strains.

Animals↗
PubMedDate not supplied

[Temperature dependence of the heat of activation in a single isometric contraction of the rat diaphragm. The effect of extra- and intracellular temperature].

Using a myothermometric method it was found that at 27 degrees and 37 degrees C the activation heat (Qa) of a single isometric contraction of the Wistar's rats isolated diaphragm averages 0.26 +/- 0.02 mcal/g and 0.60 +/- 0.13 mcal/g, accordingly, and Q10 = 2.3. It has been proved that the value of Qa depends on the gradient of intracellular temperature decrease (delta T, r = 0.89, p less than or equal to 0.01) as Qa = 1.68 delta T + 1.30 under 0.01 less than or equal to delta T less than or equal to 1.0. It was concluded that high significance of Qa for the muscles of warm-blooded points to the damaged energetics of the contraction recovery period and delta T is an intracellular informative signal which always determines the value of Qa via the feedback mechanism.

Animals↗
PubMed1980

Temperature-sensitive mutants of influenza A virus: evaluation of the Alaska/77-ts-1A2 temperature-sensitive recombinant virus in seronegative adult volunteers.

An influenza A virus recombinant bearing the surface antigens of the A/Alaska/6/77 (H3N2) wild type virus ands the two ts genes of the A/Udorn/72-ts-1A2 (H3N2) virus was evaluated for attenuation, antigenicity, and transmissibility in 28 adult volunteers all of whom possessed a preinoculation serum hemagglutination-inhibiting (HAI) antibody titer of less than or equal to 1:8 and 18 of whom also possessed a serum neuraminidase-inhibiting (NI) antibody titer of less than or equal to 1:4. The Alaska/77-ts-1A2 recombinant, which had a 37 degrees C shutoff temperature for plaque formation and ts mutations on the genes thought to code for the P1 and P3 polymerase proteins, infected 71 percent of the vaccinees when administered at a dose of 10(6.5) TCID50. Only 3 percent of the vaccinees developed symptoms in contrast to 50 percent of volunteers who received 10(4.2) TCID50 of wild type virus. Vaccinees shed virus for a shorter interval and at a lower titer than the volunteers who received wild type virus. Each ts-1A2 isolate retained the ts phenotype indicating that the recombinant was stable genetically in seronegative adults. An immunological response, as measured by a rise in serum HAI and/or NI antibody, was detected in 71 percent of the vaccinees and 87 percent of the recipients of wild type virus. Transmission of vaccine virus to susceptible contacts was not observed. The two ts-1A2 ts genes have now been transferred to two variants within the H3N2 subtype, the Vic/75 and Alaska/77 viruses, and have rendered the viruses satisfactorily attenuated for adults. The level of infectivity of the Alaska/77-ts-1A2 virus appeared to be low, however.

Adult↗
PubMed1978

Absorption and circular dichroism spectra of chloroplast membrane fragments from spinach, barley and a barley mutant at room temperature and liquid nitrogen temperature.

The absorption and CD spectra of chloroplast fragments from spinach, barley and a barley mutant (chlorophyll b-minus) were studied at temperatures of 23 degrees C and --196 degrees C. The CD spectrum of wild type barley and spinach at --196 degrees C showed troughs at 640, 653, 676 and 695 nm and a maximum at 667 nm. The CD spectrum of the barley mutant at --196 degrees C consisted of a large trough at 684 nm, a small trough at 695 nm and a positive peak at 670 nm. A new feature observed at --196 degrees C but not at 23 degrees C is the trough at 640 nm. This 640 nm CD signal is missing in the CD spectrum of the barley mutant. It is attributable to the light-harvesting chlorophyll a/b protein which appears to be missing in the mutant. Another new feature, the trough at 695 nm, was observed in the CD spectra of spinach, barley and the barley mutant at --196 degrees C. The 695 nm trough appears to be sensitive to detergents and it may be due to a labile chlorophyll a.protein complex. Possible interpretations of the data are discussed.

Chloroplasts↗
PubMed1979

Studies on temperature adaptation in Tetrahymena. Positional distribution of fatty acids and species analysis of phosphatidylethanolamine from Tetrahymena pyriformis grown at different temperatures.

Phosphatidylethanolamine of 15 degrees C-grown Tetrahymena pyriformis (NT-I) cells contains more polyunsaturated fatty acids than 39.5 degrees C-grown cells. This increase in unsaturation is due to an increase in linoleic (C18 : 2) and linolenic (C18 : 3) acids, and a decrease in myristic (C14 : 0), palmitic (C16 : 0), palmitoleic (C16 : 1) and heptadecanoic (C17 : 0) acids. Compared with 39.5 degrees C-grown cells, the proportion of palmitic acid (C16 : 0) decreased in the 1-position as does at the 2-position in 15 degrees C-grown cells. On the contrary, there is a significant increase in linoleic (C18 : 2 delta 9, 12) and gamma-linolenic (gamma-C18 : 3) acids in the 1- and 2-positions, respectively. Phosphatidylethanolamine has been subfractionated into seven different diglyceride species. In 15 degrees C cells, the amounts of fractions 2 (1-linolenoyl-2-linoleoyl) and 3 (1-linolenoyl-2-palmitoleoyl, 1-linolenoyl-2-oleoyl) increased while there was a great decrease in subfraction 7 (1-myristoyl-2-palmitoleoyl, 1-palmitoyl-2-palmitoleoyl). Since subfractions 1 and 2 contain over 70% linoleic (C18 : 2) and linolenic (C18 : 3) acids, these fractions might be composed mainly of 1-linolenoyl-2-linolenoyl and 1-linolenoyl-2-linoleoyl molecular species at 15 degrees C. These data support evidence that phosphatidylethanolamine would play a principal role as an acceptor of acyl chains for temperature acclimation.

Adaptation, Physiological↗
PubMed1975

Temperature sensitivity of protein synthesis initiation in the reticulocyte lysate system. Reduced formation of the 40 S ribosomal subunit - Met-tRNAf complex at an elevated temperature.

Analysis of protein synthesis in the rabbit reticulocyte lysate system revealed the existence of a temperature-sensitive step in chain initiation which became irreversibly inactivated in the incubation at 42 degrees C. This inactivation of initiation was accompanied by a marked reduction in formation of the 40 S ribosomal subunit - Met-tRNAf complex. Decreased protein synthesis and a decrease in formation of the 40 S complex were also evident in unfortified lysates which had been prewarmed at 42 degrees C prior to protein synthesis. Hemin did not protect such lysates. The addition of supernatant fraction of a fresh lysate did not promote recovery of the reduced protein synthesis by such prewarmed lysates. Moreover, the addition of supernatant fraction prewarmed at 42 degrees C in the presence of added hemin caused little inhibition of protein synthesis by fresh lysate. The results indicate that the supernatant fraction is not involved in the inactivation.

Animals↗
PubMed2002

Hygroscopicity of aerosol particles at low temperatures. 1. New low-temperature H-TDMA instrument: setup and first applications.

A hygroscopicity tandem differential mobility analyzer (H-TDMA) is described that allows a fast and accurate determination of the water uptake by submicrometer aerosol particles at temperatures below 0 degrees C. To avoid volatilization of semivolatile particles, the humidification works without heating the gas stream, and the gas-phase composition is not changed during the analysis. The applied scanning mobility analysis allows a fast and accurate measurement of the humidogram, but care has to be taken with too high scanning velocities leading to artifacts in the particle size measurement. During a field campaign at a high-alpine site (Jungfraujoch, 3580 m above sea level), humidograms of free tropospheric particles were measured at T= -10 degrees C. The hygroscopic growth of these particles was characterized by monomodal growth distributions, which means that in the observed size range (dry particle diameters (Do) = 50-250 nm) the free tropospheric aerosol was to a large extent internally mixed. No distinct deliquescence was observed, indicating that the multicomponent aerosol particles are present in a liquid state even at a low relative humidity (RH) <10%. At RH 85%, average hygroscopic growth factors of 1.44, 1.49, and 1.53 were measured for Do = 50, 100, and 250 nm. The estimated soluble volume fraction of the particles in the observed size range was found to be 0.79, 0.86, and 0.91, respectively.

Aerosols↗
PubMed2000

Ab initio structure determination and Rietveld refinement of a high-temperature phase of zirconium hydrogen phosphate and a new polymorph of zirconium pyrophosphate from in situ temperature-resolved powder diffraction data.

The collected in situ temperature-resolved synchrotron powder data revealed that the transformation of the recently reported three-dimensional tau-Zr(HPO4)2 to cubic ZrP2O7 goes through two intermediate phases. The first intermediate phase, rho-Zr(HPO4)2, is formed in a reversible phase transition at 598 K, which involves both rearrangement and disordering of the hydrogen phosphate groups of tau-Zr(HPO4)2. At 688 K condensation of the hydrogen phosphate groups leads to the formation of the second intermediate, a new polymorph of zirconium pyrophosphate (beta-ZrP2O7). Heating above 973 K results in the gradual transformation of beta-ZrP2O7 to cubic zirconium pyrophosphate (alpha-ZrP2O7). The crystal structures of the two intermediate phases were solved from the in situ powder diffraction data using direct methods and refined using the Rietveld method. Both phases are orthorhombic, space group Pnnm and Z = 2. The lattice parameters for the two phases are: p-Zr(HPO4)2: a = 8.1935 (2), b = 7.7090 (2), c = 5.4080 (1) A; beta-ZrP2O7: a = 8.3127 (5), b = 6.6389 (4), c = 5.3407 (3) A. The formation mechanism for the new zirconium pyrophosphate polymorph, beta-ZrP2O7, is discussed in relation to structurally restricted soft chemistry.

Diphosphates↗