ELIMINATION AND SEPARATION OF VIRUSES IN APPLE CLONES BY EXPOSURE TO DRY HEAT

1965 ◽  
Vol 45 (5) ◽  
pp. 443-454 ◽  
Author(s):  
Maurice F. Welsh ◽  
George Nyland
Keyword(s):  
Heat Exposure ◽  
Exposure Period ◽  
Virus Infections ◽  
Maximum Heat ◽  
Dry Heat ◽  
Lateral Buds ◽  
Before And After ◽  
Accurate Forecast ◽  
Minimum Heat ◽  
Stem Pitting

Virus infections have been eliminated from apple clones by propagation of lateral buds from potted apple trees after their exposure to dry heat at 38 °C for varying periods. For several clones the minimum heat exposure period imposed (7 days, following preheating 7 days at 35 °C) inactivated viruses that cause stem pitting of Virginia crab; foliage and shoot symptoms on Hopa crab; rubbery wood on Lord Lambourne apple; foliage and dieback symptoms on Spartan apple (McIntosh pucker virus); and leaf pattern, epinasty, and bark necrosis of Spy 227.The apple clones displayed wide differences in heat tolerance. Minimum heat exposure periods for virus inactivation varied among clones treated. For two clones, the buds sampled after maximum heat exposure periods, approaching survival threshold of the plants, gave higher levels of positive indexing on Spy 227, Hopa crab, and Virginia crab than those sampled after short or intermediate periods. Virginia crab stem pitting and Virginia crab decline were shown to have distinct etiology: the virus causing stem pitting proved very sensitive to heat, whereas that causing decline was heat-tolerant. Indexing before and after heat exposure provided evidence that distinct viruses or strains induce the reactions of Hopa crab and Spy 227, Hopa crab and Virginia crab, and probably also Virginia crab and Spy 227.Indexing of internodal bark chips at the time buds were removed from the heat chamber for propagation yielded readings quickly and provided a generally accurate forecast of the indexing results for trees derived from the treated buds.

Effects of weathering on failure pressure of filament-wound GFRP thermoset pipes

2010 ◽  
Vol 45 (6) ◽  
pp. 645-655 ◽  
Author(s):  
F. Al-Sulaiman ◽  
Z. Khan ◽  
N. Merah ◽  
M.A. Kounain ◽  
M. Mehdi
Keyword(s):  
Environmental Conditions ◽  
Heat Exposure ◽  
Failure Pressure ◽  
Dry Heat ◽  
Oil Transportation ◽  
Natural Exposure ◽  
Glass Fiber Reinforced ◽  
Filament Wound ◽  
Before And After

Burst tests have been performed on the glass fiber-reinforced (GFR) thermoset pipes before and after exposure to natural and accelerated environmental conditions. The main objective of this study was to explore the effects of long-term natural outdoor and artificial accelerated environmental conditions on the burst resistance of the vinyl-based and epoxy-based GFR filament wound thermoset pipes which are targeted for use in crude oil transportation. The pipes were exposed to natural outdoor and accelerated dry heat conditions. The results show that these environments did not produce any noticeable degradation in the hydrostatic burst resistance of the pipes up to 24 months of natural exposure and up to 10,000 h of dry heat exposure.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

Plasma volumes and constituents of heat-exposed men before and after acclimatization

1975 ◽  
Vol 38 (4) ◽  
pp. 570-575 ◽  
Author(s):  
L. C. Senay
Keyword(s):  
Water Movement ◽  
Venous Blood ◽  
Heat Exposure ◽  
Heat Acclimatization ◽  
Vascular Volume ◽  
Exercise Regimen ◽  
Body Weights ◽  
Before And After ◽  
Body Compartments ◽  
Considerable Loss

Five men underwent a 2-wk exercise regimen and were then exposed to 45 degrees C db, 28 degrees C wb, wind speed 1 m/s for 12 h while at rest. Body weight was maintained with 0.1% saline. One week later the exposure was repeated without rehydration. After heat acclimatization, the 12-h experiments were repeated. Frequent body weights, rectal temperatures, and venous blood samples were obtained. Results indicated that hemodilution upon acute heat exposure is partially due to protein influx into the vascular volume and the hemodilution allowed considerable loss of body water before plasma volume returned to preexposure values. Water within the vascular volume appeared to be in equilibrium with that in other body compartments before but not after acclimatization. Acclimatization altered the rate of protein transfer (and water movement) such that hemodilution was accomplished more rapidly than before acclimatization. Early hemodilution was quite labile and depended upon subject hydration during the first hour of heat exposure.

Infant Dietary Experience and Acceptance of Solid Foods

PEDIATRICS ◽  
1994 ◽  
Vol 93 (2) ◽  
pp. 271-277 ◽  
Author(s):  
Susan A. Sullivan ◽  
Leann L. Birch
Keyword(s):  
Dietary Exposure ◽  
Exposure Period ◽  
Green Beans ◽  
Solid Foods ◽  
Local Newspapers ◽  
Period 2 ◽  
Before And After ◽  
Control Food ◽  
Birth Records ◽  
Repeated Consumption

Objective. To examine the effects of dietary experience and milk feeding regimen on acceptance of their first vegetable by 4-to 6-month-old infants. Design. Longitudinal study, of 26-days duration, observing infants aged 4 to 6 months at the start of the study. Random assignment to treatments, within-subject control. Setting. General community in a medium-sized mid-western town. Subjects. Thirty-six infants and their mothers. Subjects were solicited through birth records and advertisements in local newspapers. Interventions. Infants were randomly assigned to be fed one vegetable on 10 occasions, either salted or unsalted peas or green beans, for a 10-day period. Outcome measures. Infant intake of the vegetable consumed during the 10-day exposure period; intake of salted and unsalted versions: (1) before the 10-day exposure period, (2) immediately after the exposure period; and (3) after a 1-week period of delay. Intake of a control food was also measured before and after repeated consumption of the vegetable. Adult ratings of the infants' videotaped responses during test feedings were also obtained before and after the exposure period. Results. After 10 opportunities to consume the vegetable, all infants significantly increased their intake (P &lt; .001). Although they did not differ initially, infants fed breast milk showed greater increases in intake of the vegetable after exposure and had an overall greater level of intake than formula-fed infants. Adult ratings of the infants' nonverbal responses correlated positively with infant intake. Conclusions. Infants increase their acceptance (reflected both in changes in intake and in behavioral response) of a novel food after repeated dietary exposure to that food. Relative to formula-feeding, breast-feeding may facilitate the acceptance of solid foods.

Maintenance of primary African green monkey kidney (pAGMK) and Vero cells at room temperature (25°). A system for virus isolation in community practice

1974 ◽  
Vol 20 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Julius A. A. Mingle ◽  
J. C. N. Westwood
Keyword(s):  
Herpes Simplex ◽  
Room Temperature ◽  
Adenovirus Type ◽  
Field Studies ◽  
Vero Cells ◽  
Community Practice ◽  
Virus Infections ◽  
African Green Monkey Kidney ◽  
Before And After ◽  
Simplex Virus

Primary AGMK cells and Vero cells were maintained at room temperature (25 °C) and their sensitivities tested using echovirus type 9, coxsackie B4 and B5, herpes simplex virus, vaccinia, influenza A2/Hong Kong, and adenovirus type 7. pAGMK maintained for 4 days at room temperature was found to be less sensitive to herpes simplex and coxsackie B4 whilst maintenance of Vero cells at room temperature did not affect the sensitivity. Susceptibility of these two cell cultures to prototype viruses indicated that pAGMK was more susceptible.pAGMK cells were held at room temperature both before and after inoculation with viruses and incubated at 37 °C. Cytopathic effect (CPE) was noticed in these cells earlier after switching them to 37 °C incubation than when refrigerated suspensions of the viruses were inoculated into fresh cultures that had not been subjected to room temperature incubation. The usefulness of such a procedure in field studies of virus infections is discussed.

scholarly journals Effect of Added Sugar on the Consumption of A Lipid-Based Nutrient Supplement Among 7–24-Month-Old Children

Nutrients ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 3069
Author(s):  
Harriet Okronipa ◽  
Amado D. Quezada-Sánchez ◽  
Susan L. Johnson ◽  
Cloe Rawlinson ◽  
Selene Pacheco-Miranda ◽  
...  
Keyword(s):  
Exposure Period ◽  
Primary Objective ◽  
Health Centers ◽  
Double Burden ◽  
Added Sugar ◽  
Initial Exposure ◽  
Nutrient Supplements ◽  
Before And After ◽  
Study Population ◽  
Food Mixture

Small-quantity lipid-based nutrient supplements (SQ-LNS) could help prevent malnutrition. Our primary objective was to examine the acceptability and consumption of sweetened and unsweetened versions of SQ-LNS before and after 14-days of repeated exposure. A total of 78 mother-infant dyads recruited from health centers in Morelos, Mexico, were randomized to two groups of SQ-LNS (sweetened, LNS-S; unsweetened, LNS-U). During the study, infants were fed SQ-LNS (20 g) mixed with 30 g of complementary food of the caregiver’s choice. The amount of supplement-food mixture consumed was measured before, during and after a 14-day home exposure period. We defined acceptability as consumption of at least 50% of the offered food mixture. At initial exposure, LNS-U consumption was on average 44.0% (95% CI: 31.4, 58.5) and LNS-S 34.8% (25.3, 44.0); at final exposure, LNS-U and LNS-S consumption were 38.5% (27.8, 54.0) and 31.5% (21.6, 43.0). The average change in consumption did not differ between the groups (2.2 p.p. (−17.2, 24.4)). We conclude that the acceptability of sweetened and unsweetened SQ-LNS was low in this study population. Since consumption did not differ between supplement versions, we encourage the use of the unsweetened version given the potential effects that added sugar may have on weight gain especially in regions facing the double burden of malnutrition.

scholarly journals Role of opioids in hypoxic pial artery dilation is stimulus duration dependent

1998 ◽  
Vol 275 (3) ◽  
pp. H861-H867 ◽  
Author(s):  
William M. Armstead
Keyword(s):  
Stimulus Duration ◽  
Exposure Period ◽  
Hypoxic Exposure ◽  
Relative Role ◽  
Moderate Hypoxia ◽  
Methionine Enkephalin ◽  
Cranial Window ◽  
Pial Artery ◽  
Before And After

Because methionine enkephalin contributes to and dynorphin opposes dilation during a 10-min hypoxic exposure, opioids modulate pial artery dilation to this stimulus. However, such modulation may be dependent on the duration of hypoxia. The present study was designed to characterize the modulation of hypoxic pial dilation by opioids as a function of stimulus duration in newborn pigs equipped with a closed cranial window. Hypoxic dilation was decremented in both moderate and severe groups ([Formula: see text] ≈ 35 and 25 mmHg, respectively) during 20-min and 40-min exposure periods compared with the response during 5 or 10 min of stimulation (24 ± 1, 25 ± 1, 18 ± 1, and 14 ± 1% for 5, 10, 20, and 40 min of moderate hypoxia; means ± SE). Moderate and severe hypoxia had no effect on cerebral spinal fluid (CSF) methionine enkephalin or dynorphin concentration during a 5-min exposure period. During a 10-min exposure, however, both opioids were increased in CSF. During 20- and 40-min exposure periods, CSF dynorphin continued to increase, whereas methionine enkephalin steadily decreased (962 ± 18, 952 ± 21, 2,821 ± 15, 2,000 ± 81, and 1,726 ± 58 pg/ml methionine enkephalin for control, 5, 10, 20, and 40 min of moderate hypoxia, respectively). The μ-opioid (methionine enkephalin) antagonist β-funaltrexamine had no influence on dilation during the 5-min exposure, decremented the 10- and 20-min exposures, but had no effect on 40-min exposure hypoxic dilation. Whereas the κ-opioid (dynorphin) antagonist norbinaltorphimine similarly had no effect on a 5-min exposure dilation, it, in contrast, potentiated 10-, 20-, and 40-min exposure hypoxic dilations (23 ± 1 vs. 23 ± 1, 24 ± 1 vs. 32 ± 1, 16 ± 1 vs. 24 ± 2, and 13 ± 1 vs. 23 ± 3% for 5, 10, 20, and 40-min hypoxic dilation before and after norbinaltorphimine). These data show that opioids do not modulate hypoxic pial dilation during short but do so during longer exposure periods. Moreover, hypoxic pial dilation is diminished during longer exposure periods. Decremented hypoxic pial dilation during longer exposure periods results, at least in part, from decreased release of methionine enkephalin and accentuated release of dynorphin. These data suggest that the relative role of opioids in hypoxic pial dilation changes with the stimulus duration.

scholarly journals Low-Temperature Decontamination with Hydrogen Peroxide or Chlorine Dioxide for Space Applications

2012 ◽  
Vol 78 (12) ◽  
pp. 4169-4174 ◽  
Author(s):  
T. Pottage ◽  
S. Macken ◽  
K. Giri ◽  
J. T. Walker ◽  
A. M. Bennett
Keyword(s):  
Hydrogen Peroxide ◽  
Low Temperature ◽  
Chlorine Dioxide ◽  
Exposure Period ◽  
Microbial Reduction ◽  
Space Applications ◽  
Content Type ◽  
Chlorine Dioxide Gas ◽  
Dry Heat ◽  
D Values

ABSTRACTThe currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction at temperatures of >110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effective and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative to dry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseous decontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m3exposure chamber. Five spore-formingBacillusspp. were exposed on stainless steel coupons to vaporized hydrogen peroxide and chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery ofBacillus atrophaeusandGeobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required an exposure period of 60 min to reduce bothB. atrophaeusandG. stearothermophilusby 5 logs. Of the three otherBacillusspp. tested,Bacillus thuringiensisproved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and 6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing theBacillusspp. tested within the exposure ranges by over 5 logs, with the exception ofB. thuringiensis, which was more resistant to both technologies. These results indicate that a review of the indicator organism choice and loading could provide a more appropriate and realistic challenge for the sterilization procedures used in the space industry.

Effect of Dry Heat, Direct Flame, and Straw Burning on Seed Germination of Weed Species Found in Lowbush Blueberry Fields

2016 ◽  
Vol 30 (1) ◽  
pp. 263-270 ◽  
Author(s):  
Scott N. White ◽  
Nathan S. Boyd
Keyword(s):  
Seed Germination ◽  
Exposure Time ◽  
Heat Exposure ◽  
Seed Viability ◽  
Weed Species ◽  
Dry Heat ◽  
Lowbush Blueberry ◽  
Weed Seeds ◽  
Straw Burning ◽  
Time Required

Experiments were conducted to determine the effects of dry heat, direct flame, and straw burning on germination of several weed species from lowbush blueberry fields. Dry heat experiments were designed as factorial arrangements of temperature (100, 200, and 300 C in experiment 1 and room temperature, 100, 200, and 300 C in experiment 2) and exposure time (0, 5, 10, 20, 40, and 80 s in experiment 1 and 2, 5, 10, and 20 s in experiment 2) to determine the exposure time required to reduce germination for each temperature. Susceptibility to dry heat varied across species tested, but germination of spreading dogbane, meadow salsify, fireweed, and hair fescue seeds collected from lowbush blueberry fields in Nova Scotia, Canada generally declined exponentially as a function of duration of heat exposure at the temperatures tested. Germination decreased more rapidly at higher temperatures in all species, although the duration of heat exposure required to reduce germination by 50 and 90% varied across temperatures and species. Exposure of seeds to direct flame rapidly reduced germination, with less than 1 s of exposure required to reduce seed germination of witchgrass, spreading dogbane, and meadow salsify by > 90%. Straw burning did not consistently reduce germination of hair fescue or winter bentgrass, indicating that a surface burn occurring above weed seeds may not be consistently effective at reducing seed viability. These results provide important estimates of the temperature and exposure times required to reduce viability of weed seeds in lowbush blueberry fields and suggest that thermal technologies that expose weed seeds to direct flame will be the most consistent in reducing seed viability.

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