Novel approach to fabricate keratin sponge scaffolds with controlled pore size and porosity

A compression-molding/particulate-leaching (CM/PL) method was developed to fabricate S-sulfo keratin sponges with the controlled pore size and porosity. The S-sulfo keratin was extracted from wool and was then spray-dried to give S-sulfo keratin powder. The S-sulfo keratin powder mixed with urea in advance was compression-molded together with the sieved NaCl particulates above the melting temperature of urea. The following removal of the salts and urea in water created the sponges composed of interconnected pores and the continuous S-sulfo keratin matrix. The S-sulfo keratin sponges were strong enough to handle and water-insoluble. By contrast, the sponges prepared without urea were very fragile and readily collapsed, because most of S-sulfo keratin matrix remained powdery. The pore size was in good accordance with the size of the salts, indicating that the pores were formed by leaching-out the salts. The S-sulfo keratin sponges with the regulated sizes of pores (<100, 100-300 and 300-500 microm) were fabricated, all of which had more than 90% of the porosity. Thus, CM/PL method is able to give the S-sulfo keratin sponge with the desired pore size and porosity, which might be a good scaffold for the cells in tissue engineering.     

Adsorption of low density lipoproteins onto selected biomedical polymers

This study examines the interaction of human low density lipoprotein (LDL) with a select group of biomedical polymers. The adsorption characteristics of LDL on cured filler-free poly(dimethyl Siloxane) (C-PDMS), Biomer, Cardiomat 610, Kraton 1650, poly(hydroxyethyl methacrylate) (PHEMA) and glass are presented. Adsorption of LDL to charged hydrophilic glass control surfaces occurred rapidly, reaching plateau concentrations within one minute (0.19 +/- 0.01 ug/cm2). Adsorption of LDL to polymer surfaces appeared to be dependent upon both the polymer hydrophobicity (or apolar nature), and flexibility (or dynamic nature) at the interface. Increased surface concentrations were observed for Biomer (0.32 +/- 0.01 ug/cm2) as well as other polymers which exhibited both hydrophobic and elastomeric properties. Temperature changes between 25 degrees C and 37 degrees C were found to significantly influence the surface concentration of LDL on Biomer (0.16 +/- 0.01 ug/cm2 at 25 degrees C versus 0.32 +/- 0.01 ug/cm2 at 37 degrees C). A lipid core phase transition at 36 degrees C was believed to be responsible for the temperature influence. Preliminary competitive adsorption studies of LDL with albumin (HSA) and serum on silicone surfaces suggests that LDL adsorption occurred rapidly and preferentially (0.25 +/- 0.01 ug/cm2 for LDL alone; 0.33 +/- 0.01 ug/cm2 for LDL + HSA; 0.15 +/- 0.01 ug/cm2 LDL + serum). Preliminary studies on the role of LDL in calcification were not conclusive. It can be concluded that LDL adsorption is dependent upon polymer hydrophobicity, flexibility and temperature. Competitive adsorption experiments suggests that LDL may have a substantial influence on protein adsorption.     

Dynamic mechanical studies of hydrolytic degradation in isotropic and oriented Maxon B

Hydrolytic degradation studies have been undertaken on Maxon B, a bioresorbable block copolymer of polyglycolic acid (PGA) and polytrimethylene carbonate (TMC). Isotropic and oriented samples were studied by dynamic mechanical measurements over a wide range of temperatures. In addition to mechanical tests, water content and mass loss were also determined on the degraded samples. At early stages of degradation water content was the dominant factor and plasticisation lead to reductions in the glass transition temperatures of the PGA and TMC components. Orientation was shown to give significant improvements in the mechanical properties, including overall increases in modulus and an increase in the glass transition temperature of the PGA component, which is important for the behaviour at body temperature (37 degrees C). Oriented samples also showed significantly less reduction in mechanical properties on degradation. Simple one-dimensional Takayanagi models were used to provide useful insight into the understanding of the mechanical behaviour.     

Calcium-deficient hydroxyapatite-PLGA composites: mechanical and microstructural investigation

The microstructural and mechanical properties of composites composed of calcium deficient hydroxyapatite (CDHAp) and poly(lactide-co-glycolide) (PLGA) have been investigated. The composites were formed by hydrolysis of alpha-tricalcium phosphate (alpha-TCP) to CDHAp in pressed precomposite compacts of alpha-TCP-PLGA-NaCl. The differences in hydrolysis of alpha-TCP-PLGA-NaCl for two compositions of 80:10:10 wt % and 60:20:20 wt %. were monitored by isothermal calorimetry and X-ray diffraction. The microstructural evolution and variance in final composite microstructure after hydrolysis at 37 degrees C, 45 degrees C, and 56 degrees C were examined by scanning electron microscopy. HAp-PLGA composite formed from the alpha-TCP-PLGA-NaCl (80:10:10) precomposites at 37 degrees C developed a tensile strength of 13.3 +/- 0.9 MPa, a flexural strength of 24.8 +/- 1.7 MPa, and Young's modulus of 2.8 +/- 0.3 GPa. These values were 12.00 +/- 0.2 MPa, 36.1 +/- 2.1 MPa, and 5.5 +/- 0.8 GPa for the precomposite composition 60:20:20. All these mechanical properties showed a variation with hydrolysis temperature and composition. The differences in mechanical properties were related to the final microstructures of the composites, which are governed by the morphological changes in the polymer structure at its glass transition temperature and the extent of cement-type formation of CDHAp by hydrolysis of alpha-TCP.     

Growth hormone and prolactin responses during partial and whole body warm-water immersions

AIM: To elucidate the role of core and skin thermoreceptors in the release of growth hormone (GH) and prolactin (PRL), a sequence of two experiments using whole-body (head-out) and partial (one forearm) hot water immersions was performed. METHODS: Experiment 1: Nine healthy men were exposed to head-out and partial water immersions (25 min, 38-39 degrees C). RESULTS: Head-out immersion increased the core temperature (38.0 +/- 0.1 vs. 36.7 +/- 0.1 degrees C, P < 0.001) and plasma concentration of the hormones (GH, 16.1 +/- 4.5 vs. 1.2 +/- 0.4 ng mL(-1), P < 0.01; PRL, 9.1 +/- 1.0 vs. 6.4 +/- 0.4 ng mL(-1), P < 0.05). During the partial immersion the core temperature was slightly elevated (36.8 +/- 0.1 vs. 36.6 +/- 0.1, P < 0.001), the concentration of GH increased (4.8 +/- 1.7 vs. 0.6 +/- 0.3, P < 0.05), while plasma PRL decreased (7.6 +/- 0.8, 6.0 +/- 0.6, 5.2 +/- 0.6, P < 0.01). Experiment 2: Seven volunteers immersed one forearm once in 39 degrees C and once in 38 degrees C water. The measurements were performed in 5-min intervals. The GH concentration increased gradually from the beginning of the immersions (min 10; 39 degrees C: 1.9 +/- 1.0 vs. 0.6 +/- 0.3 ng mL(-1), P < 0.01; 38 degrees C: 0.19 +/- 0.03 vs. 0.14 +/- 0.03, P < 0.05) and peaked after their completion (39 degrees C: +10 min, 3.7 +/- 2.0, P < 0.001; 38 degrees C: +15 min, 0.86 +/- 0.61, P < 0.01). The core temperature was unchanged until min 15 of the 39 degrees C bath. Thereafter, it increased about 0.15 degrees C above the baseline (P < 0.01). Immersion in 38 degrees C water did not induce core temperature changes. CONCLUSIONS: Peripheral thermoreceptors are involved in GH release when the body is exposed to elevated environmental temperature while a substantial elevation of core temperature is a precondition of PRL release.     

Synthesis and characterization of elastic and macroporous chitosan-gelatin cryogels for tissue engineering

Elastic chitosan-gelatin cryogels of varying concentration of polymer precursors have been synthesized using glutaraldehyde as a crosslinking agent. The optimum co-polymer ratio of chitosan to gelatin was found to be 1:4 at the temperature of -12 degrees C for synthesis of chitosan-gelatin hybrid cryogels. chitosan-gelatin cryogels synthesized with low viscosity chitosan were morphologically better than those formed with medium and high viscosity chitosan. Pore diameters of chitosan-gelatin cryogels as measured by scanning electron microscopy (SEM) was in the range of 30-100microm. While mercury porosimetry analysis revealed the majority of pores of the scaffold lying in the range of 30-50microm. Porosity of chitosan-gelatin cryogels was found to be greater than 90% using Archimedes's principle. Unconfined compression tests showed significant elasticity of chitosan-gelatin cryogels and maintained their physical integrity even after compressing them up to 80% of their original length. The elastic modulus varied in the range of 36-39kPa. Cyclic deformation analysis performed by compression of chitosan-gelatin cryogels with varying strains (10, 20 and 40%) showed no cracking or any significant deformation. The degradation of chitosan-gelatin cryogels was found up to 13.58+/-1.52% at 37 degrees C within 8 weeks of incubation under sterile conditions and the cryogels swelled up to 90% of their capacity within two min. Efficient cell adherence, proliferation and extracellular matrix (ECM) secretion was observed by growing fibroblast (Cos-7) cell line on chitosan-gelatin hybrid cryogels which indicate potential of the material for tissue engineering applications.     

Effect of swimming to exhaustion, at low temperatures, on serum Zn, Cu, Mg and Ca in rats

In order to study the response of plasma trace minerals during exercise in cold water at varying temperatures, three groups of ten male Wistar rats each were forced to swim until exhaustion in water at different constant temperatures (10, 20 and 32 degrees C), while another 3 groups were kept at rest in water at the same temperatures and another group at rest out of the water, at room temperature (21 degrees C). Rectal temperature (RT) was measured before and after the exercise. Samples of arterial blood were obtained under anaesthesia (pentobarbital) from the abdominal aorta after the exercise, and serum concentrations of Cu, Zn, Mg and Ca were determined by flame atomic absorption spectrophotometry (FAAS). The swimming time (ST) decreased in cold water, the values obtained at 10 and 20 degrees C being 3.3% and 8.5%, respectively, of those observed at 32 degrees C. The RT of the animals swimming at 32 degrees C was 32.5 +/- 1.8 degrees C (mean +/- SD) and fell to 25.0 +/- 2.0 and to 19.1 +/- 1.5 degrees C in those swimming, respectively, at 20 and 10 degrees C. The concentrations of Mg, Cu and Ca were significantly higher (+50%, +36% and +7%, respectively) in animals subjected to exercise with respect to the control groups in water, although there were no differences among the three groups. On the contrary, Zn rose progressively with the increase of WT (+32% at 10 degrees C, +60% at 20 degrees C and +76% at 32 degrees C).(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of chemical and mechanical properties of dental composites.

Composite materials were aged in distilled, deionized water and a solution by volume of 50% distilled, deionized water and 50% ethanol for three mon at 37 degrees C. Also investigated was the effect of aging dental glass filler powder in distilled, deionized water for one, three, six, and ten mon at 2 degrees C, 37 degrees C, and 72 degrees C. Atomic absorption analysis was performed on the aqueous media in which the samples were aged in order to determine the extent of leaching of silicon and strontium. From the leaching rates at various aging temperatures, the activation energies for silicon (10.3-16.4 j/mol) and strontium (57.0-58.4 j/mol) were determined. Aging in the 50% distilled, deionized water and 50% ethanol solution greatly increased the leaching rate of both silicon and strontium, as compared to aging in distilled, deionized water. Glass powder leached far more than the composite materials, due to an increase in exposed surface area, as well as a lack of chemical bonding to a resin matrix or a linked glass network. Temperature greatly increased the leaching rate of both silicon and strontium. Only after ten mon did strontium leach substantially more than silicon. For the dental composites investigated after 3 mon aging, Mode I fracture toughness decreased 57-68% in ethanol and 37-43% in water, and mode II fracture toughness decreased 41-49% in ethanol and 6-11% in water.     

Restoration of the Functions of the Respiratory Center in Rats after Total Cold Paralysis

White rats were cooled in water until respiratory arrest, which appeared at a brain temperature of 17.62 +/- 0.16 degrees C; animals were then removed from the water to a room at a temperature of 19-20 degrees C. Experimental animals were given 1 ml of 0.6% EDTA, which binds calcium ions, 1 min after the onset of respiratory arrest; controls received 1 ml of physiological saline. Electrical heaters were used to warm the medulla oblongata; respiratory recovery occurred at 6.0 +/- 0.3 min from the onset of respiratory arrest, when the medulla oblongata temperature was 18.62 +/- 0.15 degrees C. In controls, heating of the medulla oblongata to 18.84 +/- 0.17 degrees C did not restore respiration. EDTA bound calcium ions, facilitating transport of the excess quantities of these ions from the cell cytosol to the intercellular medium. Decreases in the cytosol calcium ion concentration to normal restored the normal regulation of metabolism in cells.     

Water intake, pleasure and water temperature in humans

The influence of water temperature on intake and affective ratings was explored in human subjects. Dehydration whether by profuse sweating (body weight loss: 289 +/- 11 g, N = 20) or mountain climbing (body weight loss: 1660 +/- 58 g, N = 20) resulted in the same intake. Maximal intake was observed for water at 15 degrees C with respectively 199.0 +/- 17.0 ml and 222.7 +/- 17.4 ml. Colder and warmer water was ingested to a lesser extent. When 20 subjects were allowed to mix water to their preferred temperature, they chose 14.9 +/- 1 degree C and drunk 211.0 +/- 19.5 ml. Votes on a pleasure/displeasure scale increased from 50 degrees C to 0 degree C. Cold water was therefore both more pleasureable and less drunk. Dehydration resulted in a negative alliesthesia for warm water. Positive alliesthesia for cold water was probably the result of hyperthermia rather than dehydration.     

Temperature dependence of non-electrolyte and sodium permeability in giant axon of squid

1. The efflux of [(14)C]urea was measured in micro-injected axons at 18 degrees C. A permeability constant for urea of (0.55 +/- 0.18) x 10(-6) cm/sec was calculated from these experiments.2. The influxes of urea, thiourea, ethylene glycol, urethane and toluene were measured in perfused axons at 18 +/- 1 degrees C. The permeability constants obtained from these determinations increased in the order listed, from (0.76 +/- 0.19) x 10(-6) cm/sec for urea to 0.80 x 10(-4) cm/sec for toluene.3. The influxes of tritiated water and sodium ions at 18 degrees C were measured in perfused axons. An average permeability of (0.78 +/- 0.22) x 10(-4) cm/sec for titriated water and an average influx of 23 +/- 6 p-mole/cm(2) sec for sodium were obtained.4. Lowering the temperature of the external sea-water bathing the axon from 18 to 5 degrees C produced a decrease of 12% in the permeability of toluene, 30% for tritiated water and urethane, 55% for ethylene glycol and urea and 60% for thiourea. There was a 50% reduction in the influx of sodium for this same temperature change.5. The results obtained with the effect of temperature on permeabilities suggest that the axonal membrane has a non-homogeneous composition. A model based on the assumption of structured aqueous channels in the membrane is postulated.     

A comparison of thermoregulatory responses in the Japanese macaque (Macca fuscata) and the crab-eating macaque (Macaca irus) during cold exposure.

Thermoregulatory responses in four male adult Japanese macaques and four male adult crab-eating macaques, weighing 6-12 kg and 6.2-8 kg, respectively, were compared at ambient temperatures (Ta) ranging from 5 degrees C to 25 degrees C. The average values +/- S.E. for some physiological measurements made at Ta of 25 degrees C in the Japanese macaque and the crab-eating macaque, respectively, were as follows: resting metabolic rate; 47.6 +/- 5.0 and 42.5 +/- 1.7 W/M2; tissue conductance; 11.9 +/- 0.8 and 8.9 +/- 0.8 W/M2/degrees C; respiratory evaporative heat loss; 4.1 +/- 0.3 and 3.2 +/- 0.5 W/M2; rectal temperature; 38.6 +/- 0.1 and 37.4 +/- 0.2 degrees C; mean skin temperature; 34.0 +/- 0.3 and 31.2 +/- 0.1 degrees C. When Ta was lowered stepwise from 25 degrees C to 20, 15, 10, and 5 degrees C successively, and maintained constant at each temperature level for 1 hr, metabolic heat production graudually increased in both species. Whe Ta was lowered from 10 degrees C to 5 degrees C, the crab-eating macaque did not show further increase in heat production and the result was a loss of thermal equilibrium with rectal temperature continuing to fall. On the other hand, the Japanese macaque maintained thermal balance even at Ta of 5 degrees C. Tissue conductance, which was significantly higher in the Japanese macaque than in the crab-eating macaque at Ta of 5, 15, and 25 degrees C, decreased in both species at Ta was lowered from 25 degrees C to 15 and 5 degrees C. The specific differences in thermo-regulatory responses are considered to be adaptational, relative to the natural habitat of thw two species studied.     

Conservation of phage reference materials and water samples containing bacteriophages of enteric bacteria

The survival was determined in different conservation conditions of: somatic coliphages, F-specific RNA bacteriophages and phages infecting Bacteroides fragilis proposed as model micro-organisms for water quality control. Titres of phages of all groups either in pure culture phage suspensions or in naturally occurring phage suspensions were stable at (-70+/-10) degrees C and at (-20+/-5) degrees C when protected with glycerol. Moreover, phage analysis of stored suspensions demonstrated that their numbers were homogeneous, both between vials and within vials, and consequently they can be used as reference materials. Furthermore, changes in the storage temperature of the vials cause unpredictable changes in the numbers of bacteriophages. Consequently, phage reference materials and samples containing a quantitative number of phages must be maintained and dispatched at a constant temperature. Consequently, the results indicate that bacteriophages should be packed in dry ice during transport and storage. Finally, the number of phages in water samples stored at (5+/-3) degrees C in the dark does not decrease significantly during the first 72 h of storage. In addition, phage concentrates from natural samples obtained by adsorption-elution to cellulose nitrate filters and mixed with 10% glycerol were stable at least for 2 months at (-70+/-10) degrees C and at (-20+/-5) degrees C.     

Temperature dependence of commercially available diode detectors

Temperature dependence of commercially available n- and p-type diodes were studied experimentally under both high instantaneous dose rate (pulsed) and low dose rate (continuous) radiation. The sensitivity versus temperature was measured at SSD = 80 or 100 cm, 10 x 10 cm2, and 5 cm depth in a 30 x 30 x 30 cm3 water phantom between 10 degrees C and 35 degrees C. The response was linear for all the diode detectors. The temperature coefficient (or sensitivity variation with temperature, svwt) was dose rate independent for preirradiated diodes. They were (0.30 +/- 0.01)%/degrees C, (0.36 +/- 0.03)%/degrees C, and (0.29 +/- 0.08)%/degrees C for QED p-type, EDP p-type, and Isorad n-type diodes, respectively. The temperature coefficient for unirradiated n-type diodes was different under low dose rate [(0.16 to 0.45)%/degrees C, continuous, cobalt] and high instantaneous dose rate [(0.07 +/- 0.02)%/degrees C, pulsed radiation]. Moreover, the temperature coefficient varies among individual diodes. Similarly, the temperature coefficient for a special unirradiated QED p-type diode was different under low dose rate (0.34%/degrees C, cobalt) and high instantaneous dose rate [(0.26 +/- 0.01)%/degrees C, pulsed radiation]. Sufficient preirradiation can eliminate dose rate dependence of the temperature coefficient. On the contrary, preirradiation cannot eliminate dose rate dependence of the diode sensitivity itself.     

The effect of water temperature on the hormonal response to prolonged swimming.

The relationship between thermoreception, hormonal secretion and muscular activity was studied. 6 men swam 60 min in 21, 27 and 33 degrees C water at a speed requiring 68% of VO2 max (determined in 27 degrees C water). Rectal temperature increased in 33 degrees C (1.3 +/- 0.2 degrees C, mean and S.E.) and 27 degrees C (0.7+/- 0.1 degrees C) expts. but decreased in 21 degrees C expts. (0.8 +/- 0.3 degrees C). Changes in esophageal and muscle temperatures parallelled changes in rectal temperature. Plasma noradrenaline was higher in 33 degrees C than in 27 degrees C expts. and growth hormone, cortisol and glucagon concentrations increased in 27 degrees C and 33 degrees C expts. only. Insulin concentrations were uniformly depressed during swimming at the different water temperatures. In 21 degrees C expts. noradrenaline and adrenaline concentrations were higher than in 27 degrees C expts. VO2, carbohydrate combustion and peak lactate were slightly lower in 33 degrees C expts. Plasma glucose decreased slightly and FFA and glycerol concentrations increased identically in all expts. Heart rate increased continuously during swimming in 27 degrees C and 33 degrees C expts., but not in 21 degrees C expts. In conclusion the rise in body temperatures normally observed during exercise enhances the exercise induced increases in the plasma concentrations of noradrenaline, cortisol, growth hormone and glucagon. Decreased body temperatures may elicit catecholamine secretion as a direct consequence of thermoreception. Shivering may account for previously observed decreases in insulin secretion during cold stress but not for increases in cortisol and growth hormone.     

Dynamic mechanical properties of multiphase acrylic systems

The influence of type and quantity of five different dimethacrylate crosslinking agents on the dynamic mechanical properties of multiphase acrylic systems has been studied. These materials, commonly used in bioengineering, were processed by polymerization of a mixture of liquid methacrylate monomers, and poly(methyl methacrylate) powder. The specimens were made with various ratios of methyl methacrylate and dimethacrylate crosslinking agents in the monomer liquid. Two different processing conditions were used, heat-polymerization at 100 degrees C and autopolymerization at 45 degrees C. By using a forced torsional vibration apparatus the storage modulus (G'), loss modulus (G"), and dissipation factor (tan delta) were determined over the temperature range -60 degrees C to 140 degrees C at frequencies of 0.1, 1.0, 10, and 100 rad/s. In the autopolymerized materials, the glass transition temperature (Tg), as determined via tan delta data, increased with increasing quantities of crosslinking agents. The storage modulus likewise increased. In the heat-polymerized materials only minor variations in modulus and tan delta with type and quantity of crosslinking agents were observed. Tg values of the heat-polymerized materials were, in all cases, greater than those of the autopolymerized materials.     

Effect of various sampling condition on the measurement of circulating TSH and free thyroxine]

We report here the effect of various sampling and storage condition on the measurement of circulating TSH and free thyroxine (FT4). Blood samples were obtained from five normal subjects using four kinds of sampling tubes; plane glass tube, glass tube containing serum separator, and glass tube containing EDTA-2Na or heparin-sodium. We stored whole blood, serum or plasma at low temperature (4-8 degrees C) or at room temperature (20-25 degrees C) from one hour to thirteen days. Both values of EDTA-plasma TSH and FT4 were significantly lower than those of serum samples, EDTA-plasma TSH value was increased gradually during storage at room temperature but not at low temperature. Serum or plasma FT4 values were decreased during storage at room temperature but not at low temperature. In conclusion, circulating TSH and FT4 values are influenced by different sampling tubes and, serum or plasma TSH and FT4 are not always stable under the storage condition at room temperature. Serum samples obtained by using plane glass tube and kept at low temperature give us more reliable values of TSH and FT4.     

Press-formable CaO-MgO-SiO(2)-TiO(2)-Ag(2)O glass as a biomaterial

Glass-ceramics were investigated to obtain a glass with a composition of CaO. MgO. 2SiO(2). 0.375TiO(2). 0.007Ag(2)O. The glass melted at 1500 degrees C and could be cast. Crystallization of diopside of this glass is controlled by volume nucleation and growth processes. In a crystallization treatment at 850 degrees -870 degrees C, this glass presented a milky white, semitransparent color. The crystals formed were diopside, their crystal grain diameter was 1-2 micrometer, and crystallization was 15-25%. The bending strength of the glass produced by a crystallization treatment of 25 min at 850 degrees C was 400 MPa, which is suitable for artificial bones. This crystallized glass also was extremely stable, with no weight loss after stability testing in artificial saliva. The softening point, as determined from the viscosity curve, was 830 degrees C, and the crystallization temperature was 895 degrees C. Thus this glass can be press-formed at a temperature of 830 degrees -880 degrees C. Actual press-forming at a pressure of 0.64 MPa was carried out for 40 min at 850 degrees C and resulted in the formation of desired shapes. Given its ready formation into desired shapes and its great strength after crystallization, such glass is applicable for use as artificial bones and as dental roots and crowns.     

Influence of hydroxyl content on selected properties of 45S5 bioactive glass

Numerous material properties may be influenced by the concentration of chemically dissolved hydroxyl species within a glass. A tube furnace connected to a steam generator was used to create hydroxyl-saturated 45S5 glass under 1 atm of water at 1100 degrees C. Selected properties of as-melted and hydroxyl-saturated samples were compared to assess the sensitivity of 45S5 to excess hydroxylation. The glass transition temperature and the peak crystallization temperature of the treated 45S5 glass were reduced in comparison to the as-melted 45S5 glass. In addition, the treated glass exhibited a broad endothermic signal that may be indicative of enhanced viscous flow. A simple dissolution experiment indicated that the treated 45S5 glass was also less durable than the as-melted 45S5 glass.     

Fever and tachycardia in a bird (Gallus domesticus) after simple handling

Three Gallus domesticus cocks were reared separately in a climatic chamber at 22 degrees C, with lights on at 0600 and off at 1800 h. Food and water were available at all times. At noontime, one bird was handled for the purpose of taking cloacal, comb, and foot temperatures every 3 min for 18 min. Repeated handling produced a fever characterized by a mean rise in core temperature from 41.1 +/- 0.3 degrees C to 41.6 +/- 0.3 degrees C and an initial peripheral vasoconstriction, as shown by a drop in skin temperatures. Maximum core temperature was only 39.9 +/- 0.2 degrees C when the birds received intraperitoneal salicylate 1 h before handling. It is concluded that handling causes a fever in birds. The birds were equipped with an electrocardiogram radio transmitter, and their heart rates were recorded at a distance. When simply touched by an experimenter, the birds' mean heart rate rose from 198 +/- 6 to 249 +/- 15 beats/min. We conclude that fever and tachycardia might indicate the existence of emotion in birds.