Min Heat Research Articles

Functional properties of Lactobacillus plantarum strains: A study in vitro of heat stress influence

Functional properties of two Lactobacillus plantarum strains (Lp 813 and Lp 998) were evaluated (in vitro) before and after heat adaptation and shock. The stress conditions were selected considering a previous work: 55 °C – 15 min (heat shock) and 45 °C – 30 min (thermal adaptation), both performed in MRS broth. The functional properties evaluated were: a-survival to simulated gastrointestinal tract (GIT: saliva + bovine pepsina solution brought to pH 2.3 in 90 min, bile solution 1% w/v pH 8–10 min and bile + pancreatin solution pH 8–30 min), b-co-aggregation with Saccharomyces cerevisiae to simulate intestinal epithelia adhesion, c- auto- and co-aggregation with enteric pathogens (Escherichia coli and Salmonella enteritidis) and d-use of prebiotic compounds (inulin, soluble corn fiber, lactulose and raffinose) evaluated for kinetics of growth. Heat treatments (generally) affected the studied functional properties as follows: a-diminished the resistance to acidic step and improved survival undergoing bile-pancreatin step in GIT simulation, b-mean values of auto-aggregation and co-aggregation with yeast or pathogens were not significantly modified, despite an increase in variability and c-prebiotic use diminished in the case of strains subjected tothermal treatments except for raffinose, which showed to have been better employed in this last case. These results could be very useful when it comes to the selection of microorganisms to be used and conserved in processes and methodologies that involve high temperatures as a stress factor (spray drying or cheese elaboration).

ENHANCEMENT OF INULINASE PRODUCTION FROM AN Acetobacter sp. IN SUBMERGED CULTURES

Recently, inulinases one of the most important enzymes which have gained much attention in industrial purposes. They can be applied for production of high fructose syrup from inulin and could reduce the process steps, resulting in cost reduction and increasing the amount of products. Acetobacter sp. produced extracellular inulinase in vitro. Maximum inulinase production was obtained at pH 7.0, 300C temperature, ammonium sulphate as nitrogen source, inoculum volume 5% (v/v), 1% sucrose as additional carbon source and 48 hr after inoculation.The enzyme showed maximum activity at pH 7 and 50 0C. The enzyme was stable more than 80% of its maximal activity at 30-50 0C after 30 min heat treatment.

The overproduction of Synechocystis sp. PCC 6803 heat-shock protein (Sll0170) protects Escherichia coli against high-temperature stress

The most important role of molecular chaperones, especially under extreme temperature, is in handling with the impact of such stress on proteins and avoiding loss of their native conformation. Molecular chaperones play roles in the folding, transport, synthesis and quality control of other proteins under extreme temperature. The genome of the cyanobacterium Synechocystis PCC 6803 includes three dnaK genes (encoding heat-shock protein 70, Hsp70). The role of the second Hsp70 protein (Sll0170; DnaK2) in the acquisition of thermotolerance in Escherichia coli cells was investigated. Escherichia coli strain BL21 (DE3) was transformed with an expression vector (pTYB21) carrying the coding sequence of the Sll0170 gene under the control of the lac promoter. The recombinant cells which showed inducible expression of DnaK2 were observed to have improved viability compared to the wild-type strain upon transfer from 37 °C to 52 °C for up to 2, 4 and 6 min. Moreover, the growth of the wild-type cell culture decreased to 64% of that of the recombinant cell culture, following a transient (15 min) heat shock at 45 °C after which the culture was subsequently transferred back to 37 °C. Interestingly, the recombinant E. coli cells showed significantly faster culture growth than the wild-type cells at 37 °C.

Low temperature pyrolysis properties and kinetics of non-coking coal in Chinese western coals

Chinese western low-rank coals known as for its favorable characteristics play a key role in the production of coal oil. In this work, based on the changes in element occurrence during low-temperature pyrolysis of coal, the kinetic and thermodynamic characteristics of coal at 400–500 °C temperatures with 10 °C/min heat rate were studied, which resulted in the drastically cracking of aliphatic groups. However, a significant amount of oxygen-containing functional groups were also found during coal pyrolysis at low temperature followed pseudo-first-order kinetics. According to the low-temperature thermal kinetics analysis of different coals, the activation energy of coking coal is higher than that of non-coking coals, and the activation of non-coking coals is relatively low under the same pyrolysis conditions. The objective of this work is to provide theoretical data about the pyrolysis characteristics of non-coking coal at low temperature and increase the non-coking coal proportion in coking proceeding.

Electrical properties optimization of silver nanowires supported on polyethylene terephthalate

ABSTRACTThe aim of this study is the enhancement of the electrical properties of thin films obtained from silver nanowires (AgNWs) deposited on a flexible polyethylene terephthalate (PET) support. First, AgNWs were obtained by the “polyol” liquid phase synthesis method in the presence of chloride ions. After purification, the AgNWs were successively deposited on a flexible support of PET by doctor blade method. To improve the adhesion of the AgNWs coating to the substrate, thin films of polymethyl methacrylate (PMMA) were interposed between the layer of AgNWs and PET substrate. The properties of the thin films have been studied depending on the number of AgNWs layers and heat treatment procedure. Characterization of pure AgNWs as well as of AgNWs/PMMA/PET structures has been carried out by x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray analysis, transmission electron microscopy, UV–Vis spectroscopy, and scanning probe microscopy. The sheet resistance of the transparent conducting films was determined by four point probe measurement. Best results in terms of homogenous conductance across the film and optical transmittance have been obtained for samples prepared by deposition of four successive layers of AgNWs. Further heat treatment improved the conductivity of AgNWs on the PMMA/PET substrate. For these films, the sheet resistance decreased from 41.25 to 29.55 Ω/sq after 40 min of heat treatment in air at 150°C.

A Time Resolved Study of Precoated AISI 441 for SOFC Interconnects Using STEM-EELS - Part I

Precoated AISI441 for SOFC interconnectors were investigated by STEM-EELS looking at the diffusion processes in the initial stage of the oxidation. The PVD coating contained Ce and Co/Mn-alloy in two layers with at total thickness of 800nm. The samples were exposed up to 1000 hours at 800°C then characterized by TEM. Multiple linear least squares (MLLS) fitting of reference spectra aids the interpretation of the elemental maps due to overlapping edges (Figure 1). Within 4 min heat treatment the oxidation front has reached the substrate steel and Cr2O3 is forming at the stainless steel interface. CeO2 acts as the barrier line for Cr and is situated between the Cr-containing spinels and the (Co,Mn)-spinel after 72 h heat treatment. Figure 1

Solution combustion synthesis of Brownmillerite-type Ca2AlMnO5 as an oxygen storage material

Brownmillerite-type Ca2AlMnO5 exhibits remarkable oxygen uptake/release capability, and therefore is a promising material for achieving energy efficient air separation. This study investigates optimized conditions for the glycine-nitrate-based solution combustion synthesis (SCS) of Ca2AlMnO5. The effects of glycine content and duration of heat treatment on the morphology, crystallinity, and oxygen uptake/release performance of the products were investigated. Single phase Ca2AlMnO5, whose maximum reversible oxygen uptake/release capacity is about 3.0 wt%, was successfully synthesized by combination of SCS with various quantities of glycine and heat treatment at 1250 °C for various lengths of time. Greater crystallinity and larger capacities for reversible oxygen uptake/release were obtained from products prepared with longer periods of heat treatment. Single phase Ca2AlMnO5 can be synthesized by a combination of SCS and just 1 min of heat treatment at 1250 °C.

A Time Resolved Study of Precoated AISI 441 for SOFC Interconnects Using STEM-EELS - Part II

Precoated AISI441 for SOFC interconnectors were investigated by STEM-EELS looking at the diffusion processes in the initial stage of the oxidation. The electron beam physical vapour deposition (EB-PVD) coating contained Ce and Co/Mn-alloy in two layers with at total thickness of 800 nm. The samples were exposed up to 1000 hours at 800°C, and then characterized by STEM-EELS. Multiple linear least squares (MLLS) fitting of reference spectra aids the interpretation of the elemental maps due to overlapping edges. Within 4 min heat treatment the oxidation front has reached the substrate steel and Cr2O3 is forming at the stainless steel interface. CeO2 acts as the barrier line for Cr and is situated between the Cr-containing spinels and the (Co,Mn)-spinel after up to 168 h heat treatment.

A Time Resolved Study of Precoated AISI 441 for SOFC Interconnects Using STEM-EELS - Part I

Precoated AISI441 for SOFC interconnectors were investigated by STEM-EELS looking at the diffusion processes in the initial stage of the oxidation. The electron beam physical vapour deposition (EB-PVD) coating contained Ce and Co/Mn-alloy in two layers with at total thickness of 800 nm. The samples were exposed up to 1000 hours at 800°C, and then characterized by STEM-EELS. Multiple linear least squares (MLLS) fitting of reference spectra aids the interpretation of the elemental maps due to overlapping edges. Within 4 min heat treatment the oxidation front has reached the substrate steel and Cr2O3 is forming at the stainless steel interface. CeO2 acts as the barrier line for Cr and is situated between the Cr-containing spinels and the (Co,Mn)-spinel after up to 168 h heat treatment.

Application of peptidases from Maclura pomifera fruit for the production of active biopeptides from whey protein

A crude extract containing serine peptidases, was prepared from latex of Maclura pomifera fruits. Peptidases were isolated by precipitation with one volume of ethanol with a yield of 5.4 ± 0.4 Ucas per milligram of protein. This extract was used for hydrolysis of bovine whey proteins at 45 °C and pH 6.5. Proteolytic activity was 99% inactivated after 5 min of heat treatment (100 °C). Major whey proteins degradation profile was analysed by tricine SDS-PAGE. After 180 min of hydrolysis alpha-lactalbumin (α-LA) and beta-lactoglobulin (β-LG) were almost completely degraded. Hydrolysis degree was 31.3 ± 1.7% at 180 min of reaction and the peptides produced that were smaller than 3 kDa were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC). Angiotensin-converting enzyme (ACE) inhibitory activity and antioxidant capacity were detected in the hydrolysates and IC50 values for 180 min of hydrolysis were 0.53 ± 0.02 and 4.44 ± 0.44 mg/ml, respectively. One peptide sequence deduced from peptide masses in the 180 min filtered hydrolysate, coincided with an ACE-inhibitory peptide reported by other author. The results support the conclusion that, by the presence of ACE-inhibitory and antioxidant peptides, it would be possible to use these whey protein hydrolysates for functional food manufacturing.

Effects of heat shock and salinity on barley growth and stress-related gene transcription

The effects of a short (30 min) heat shock (HS) on plants subsequently grown under a salinity stress (SS, 200 mM NaCl) for 10 d were investigated in barley (Hordeum vulgare L.) cv. Tokak 157/37. The maximum temperature for HS allowing plant survival was 45 °C. The root length was significantly decreased by SS, whereas HS alone did not affect root growth. Interestingly, HS stimulated root elongation under SS. An osmotic adjustment was promoted in leaves by SS. On the contrary, HS increased the osmotic potential in leaves in the absence of SS, and partly counteracted the effect of SS in the HS+SS treatment. Cu/Zn-SOD, HvAPX, HvCAT2, HSP17, HSP18, and HSP90 were transcribed in leaves of HS-treated plants, but not in control plants. The HSP70 was constitutively transcribed in both the SS and control plants, but after HS, a shorter amplicon was also observed. The genes coding antioxidants, Cu/Zn-SOD, HvCAT2 and HvAPX, were differentially influenced by SS or HS+SS in the roots and leaves. In the roots, the mRNA content of BAS1, HvDRF1, HvMT2, and HvNHX1 increased after the HS treatment. In a recovery experiment in which plants were grown to maturity after HS and HS+SS stress exposure, the plant height increased and the time to maturity was reduced in comparison with SS. Our results show that HS could stimulate plant growth and reduce some of the negative effects of SS, and that it affected the transcription of several stress-related genes.

Linoleic acid binding properties of ovalbumin nanoparticles

In the present work, ovalbumin (OVA) solutions (10g/L, 50mM NaCl, pH 7.5) were heat-treated at 75, 80 and 85°C (namely, OVA-75, OVA-80 and OVA-85, respectively), from 0 to 25min. OVA nanoparticles (OVAn) around 100nm were obtained. For 3min of heat treatment, OVAn sizes increased with temperature, but for a heating time longer than 10min, OVA-75 showed the highest size values. OVAn surface hydrophobicity increased 6–8 folds in comparison with native OVA and wavelength blue shifts of 25–30nm in maximum fluorescence intensity were registered. These results suggest that buried hydrophobic residues were exposed to the aqueous medium. Binding experiments with linoleic acid (LA) as polyunsaturated fatty acid (PUFA) model were carried out. Firstly, binding ability of OVAn was determined from LA titration curves of intrinsic fluorescence measurements. OVA-85 at 5min presented the highest binding ability and it was used for further binding properties studies (turbidity, particle size distribution – PSD – analysis and ζ-potential measurements). Turbidity measurement and PSD analysis showed that OVAn–LA nanocomplexes were formed, avoiding LA supramolecular self-assembly formation. The union of LA to OVAn surface confers them significant lower ζ-potential and larger size. Hence, fluorescence and ζ-potential results showed that LA would bind to OVAn by mean of hydrophobic interactions. Information derived from this work could be important to potentially use OVAn as PUFA vehiculization with applications in several industrial sectors (food, pharmaceutical, cosmetics, etc.).

Effects of solvents on the synthesis of CuInSe2 nanoparticles for thin film solar cells.

Chalcopyrite CuInSe2 (CIS) nanoparticles were synthesized in oleic acid, 1-octadecene, oleyl amine and tetraethylene glycol at temperature above 200 degrees C. Depending on the solvent used and reaction temperature, the obtained nanoparticles had different shapes, sizes, chemical compositions, and crystal and thermal properties. CIS powders synthesized in oleic acid, 1-octadecene and oleyl amine above 200 degrees C exhibited chalcopyrite structure. On the other hand, powders prepared in tetraethylene glycol contained a mixture of CIS and CuSe compounds. The CIS powder obtained in oleyl amine had a high thermal stability over 500 degrees C. CIS thin films prepared from nanoparticles were heat-treated in order to observe changes in their property. After 10 min heat-treatment at 500 degrees C, their crystal structure and chemical composition were slightly changed, and their band gap energies were ca. 1.01 eV except in the case of powders prepared in tetraethylene glycol.

Heat, acid and cold stresses enhance the expression of DnaK gene in Alicyclobacillus acidoterrestris

DnaK gene coding for the 70-kDa heat shock protein (Hsp70) plays an essential role in protecting microorganisms from a hostile environmental and food preservation conditions such as heating, acidity, alkalinity and chilling and is believed to be associated with the thermo-acidophilic resistance of Alicyclobacillus acidoterrestris (A. acidoterrestris). In this study, the genome walking technique was used to clone DnaK gene and the bioinformatics characteristics of DnaK was predicted using online software. The growth and sporulation of A. acidoterrestris were explored and the expression levels of DnaK gene in A. acidoterrestris were determined by quantitative real time PCR (qRT-PCR) under heat, acid and cold stresses. DnaK gene (GenBank Accession No. HQ893543) from A. acidoterrestris DSM 3922T contains an open reading frame of 1854bp coding for 617 amino acids and the deduced amino acid sequence is homologous to the DnaK chaperone protein of Alicyclobacillus acidocaldarius. The protein translated from DnaK gene of A. acidoterrestris was characterized as a thermostable protein based on the primary and secondary structure analyses which predict the functions of amino acid sequence, and folding and coiling polypeptides, respectively. Three environmental stresses including heat stress at 70°C, acid stress at the pH of 1.0, and cold stress at 0°C were imposed on A. acidoterrestris to investigate the expression of DnaK. The transcriptional level of DnaK gene under heat stress increased quickly to peak level in 5min and then dropped to the minimum level in 15min; the transcriptional levels of DnaK gene under acid stress increased markedly in 0.5h to peak level in 1h and then decreased to the minimum level in 3h, and the peak mRNA expression levels differed between heat and acid stress. DnaK expression levels of 5min heat stress and 1h acid stress were 1.4 times and 4.3 times higher than those of the control under non-stress condition at 45°C, respectively. In response to cold stress at 0°C, the DnaK expression level decreased drastically to 0.48 times of the control after 1h cold treatment. Spores of A. acidoterrestris were produced after the bacteria received 40min heat stress, 5h acid stress or 6h cold stress, which suggested that DnaK gene regulates the stress resistance of A. acidoterrestris against abrupt abiotic stimuli differently from sporulation. However, the expression of DnaK under stress conditions demonstrated the different pattern of changes as the induced stresses continued, especially in the case of acid stress, which implied that a more complicated mechanism of DnaK regulation is involved in the stress response of A. acidoterrestris.

Redistribution of acetyl groups on the non-reducing end xylopyranosyl residues and their removal by xylan deacetylases.

Monoacetylated xylosyl residues of the main hardwood hemicellulose acetylglucuronoxylan undergo acetyl group migration between positions 2 and 3, and predominantly to position 4 of the non-reducing end xylopyranosyl (NRE-Xylp) residues which are amplified by saccharifying enzymes. On monoacetylated non-reducing end xylopyranosyl (NRE-Xylp) residues of xylooligosaccharides the acetyl group migrates predominantly to position 4 and hinders their hydrolysis by β-xylosidase. Acetyl migration on the NRE-Xylp residues and their enzymatic deacetylation by various xylan deacetylases was followed by (1)H-NMR spectroscopy and TLC. A 5-min heat treatment of 4-nitrophenyl 3-O-acetyl-β-D-xylopyranoside was sufficient to establish equilibrium between monoacetate derivatives acetylated at positions 2, 3 and 4. Rapid acetyl migration along the NRE-Xylp ring at elevated temperature was confirmed in derivatives of methyl β-1,4-xylotrioside (Xyl3Me) monoacetylated solely on the NRE-Xylp residue, the analogues of naturally occurring acetylated xylooligosaccharides. The Xyl3Me monoacetates were used as substrates to study regioselectivity of the NRE-Xylp residue deacetylation by various acetylxylan esterases (AcXEs) of distinct carbohydrate esterase (CE) families. CE1, CE4 and CE6 AcXEs hydrolyzed considerably faster the 2″-O-acetyl derivative than the 3″-O-acetyl derivative. In contrast, the CE16 acetyl esterase preferred to attack the ester bond at position 3 followed by position 4. Redistribution of acetyl group on the NRE-Xylp residues is extremely rapid at elevated temperature and includes the formation of 4-acetate. Regioselectivity of AcXEs and CE16 acetyl esterase on these monoacetates is complementary. The formation of all isomers of acetylated xylosyl residues must be taken into account after a long-term incubation of acetylxylan and acetylated xylooligosaccharides solutions or upon their treatment at elevated temperatures. This phenomenon emphasizes requirement of both types of xylan deacetylases to enable a rapid saccharification of xylooligosaccharides by glycoside hydrolases.

Grain growth and pore elimination in Inconel 625 deposited by APS

Due to the nature of the thermally sprayed structures, the mechanical and physical properties of such structures are completely different from commercially produced alloys such as cast and forged structures. The existence of lamellae, splat boundaries, micro cracks and pores and a high level of residual stresses due to the rapid solidification process could affect the properties of the thermally sprayed alloys. In order to improve the properties of the as-sprayed structure, post-deposition heat treatment is necessary. In the current study, Inconel 625 was deposited by atmospheric plasma spraying. Then, the microstructural evolution during the post-deposition heat treatment was investigated. Splat boundaries and micro crack elimination, pore morphology conversion, and grain growth mechanisms were comprehensively elucidated. Results showed that the splat boundaries disappeared partially after heat treatment. The pore morphology converted from irregular to spherical shape. Initially, the grain growth rate accelerated after 200min. The mean grain size increased from less than 1μm to 3.5μm after 300min isothermal treatment time. The rate of pore growth was fast at first 200min heat treatment time and reduced slightly after around 200min heat treatment time.

Experimental and theoretical study of Ti20Zr20Hf20Nb20X20 (X = V or Cr) refractory high-entropy alloys

We investigated the microstructure and mechanical properties of Ti20Zr20Hf20Nb20X20 (X=V or Cr) high-entropy alloys (HEA), produced by induction melting and casting in inert atmosphere. The structures of these alloys were studied via X-ray diffractometry and scanning electron microscopy. Results show that Ti20Zr20Hf20Nb20V20 has mainly the body centered cubic (BCC) structure, whereas the BCC matrix of Ti20Zr20Hf20Nb20Cr20 contains small amount of Cr2Nb and Cr2Hf intermetallic compounds. Ti20Zr20Hf20Nb20V20 alloy shows the high strength and the homogeneous deformation under compression at room temperature. The strength and hardness of Ti20Zr20Hf20Nb20Cr20 alloy are further enhanced by the Cr-containing Laves phases segregated during casting. The structural and mechanical properties remained almost unchanged after a short time (10min) heat treatment at 573, 773, 973 and 1173K indicating the resistance to working temperature peaks for these two alloys. Ab initio calculations predict ductile behavior for these and similar refractory HEAs. The theoretically calculated Young's modulus E is in good agreement with the experimental ones.

Fabrication of glycopolymer/MWCNTs composite nanofibers and its enzyme immobilization applications

Glycopolymer (poly(AN-co-OVSEG))/MWCNTs (multiwalled carbon nanotubes) composite nanofibers are fabricated using a facile approach combining enzymatic synthesis, radical polymerization and electrospinning. The structure of the glycopolymer was confirmed by FT-IR and 1H NMR. Poly(AN-co-OVSEG)/MWCNTs composite nanofibers were prepared using electrospinning and characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hydrophilic properties of the composite nanofibers surfaces were increased since the contact angle of poly(AN-co-OVSEG)/MWCNTs composite was reduced from 65.5° to 37° compared to (PAN). As an enzymatic model catalase (CAT) was loaded (ca. 55.0mg/g) to the poly(AN-co-OVSEG)/MWCNTs nanofibers. The optimum temperature for poly(AN-co-OVSEG)/MWCNTs nanofibers increased from 25°C to 45°C compared to free CAT. The covalently immobilized enzymes conjugate exhibited 60% activity at 60°C, while the free enzyme was entirely inactivity after 5min heat treatment. The immobilized CAT retained 70% of its initial activity after 5 cycles of decomposition of hydrogen peroxide.

Thermostable Sites and Catalytic Characterization of Xylanase XYNB of Aspergillus niger SCTCC 400264

In order to improve the expression of heat-resistant xylanase XYNB from Aspergillus niger SCTCC 400264, XynB has been cloned into Pichia pastoris secretary vector pPIC9K. The XynB production of recombinant P. pastoris was four times as E. coli, the Vmax and specific activity of XynB reached 2,547.7 μmol/mg and 4,757 U/mg, respectively. And the XynB still had 74% residual enzyme activity after 30 min-heat treatment at 80°C. The van der Waals force analysis in XYNB (ACN89393 and AAS67299), there is one more oxygen radicals in AAS67299 in their catalytic site, indicating that the local cavity is much more free, and it is more optimal for substrate binding, affinity reaction, and proton transfer etc, and eventually increasing enzyme activity. The H-bonds analysis of XYNB indicated that there are two more H-bonds in 33rd Ser of XYNB (AAS67299) than 33rd Ala(ACN89393 ), two H-bonds between Ser70 and Asp67.

Heart failure patients have impaired thermoregulatory response during exercise (884.2)

Objective: During a thermoregulatory challenge such as exercise in the heat, skin blood flow (SkBF) must rise so as to maximise radiant, convective and evaporative heat loss. There is some evidence to suggest that in Heart Failure (HF) the rise in SkBF is blunted during passive heat exposure. Indeed, HF patients may be unable to adequately increase cardiac output to service multiple vascular beds during a thermoregulatory challenge. The aim of this study was to compare the thermoregulatory responses to exercise in the heat in a group of HF patients (n=7, 62 + 7 yr, NYHA Class I‐II) and age‐matched healthy controls (CON; n=6, 63 + 8 yr). Methods: HF and CON exercised for 60 min heat (30oC, 60% relative humidity) at ~70% peak oxygen uptake (VO2). Core temperature (Tc) and skin temperature (Tsk) were measured continuously. Skin blood flow was measured every 10 minutes using Laser Doppler Flowmetry. Skin conductance was determined from the ratio of SkBF and mean arterial pressure. Results: HF patients exercised with a significantly (p<0.05) lower metabolic heat load when compared to CON (VO2: HF 1.26 + 0.32; CON 1.83 + 0.52 l/min). Despite this, both HF and CON had a similar and significant increase (P<0.05) in Tc (HF: pre: 37.2+ 0.4, end ex: 38.2 + 0.4oC; CON: pre 37.3 + 0.2, end ex: 38.2 + 0.4oC) and Tsk (HF: pre: 33.0+ 0.6, end ex: 35.0 + 0.5oC; CON: pre 32.6 + 0.6, end ex: 35.7 + 0.6oC). HF patients had a significantly lower (p<0.01) increase in SkBF (HF: 101 + 30; CON: 302 + 64 AU) and skin conductance (HF: 1.0 + 0.6; CON: 2.9 + 1.1 AU). Conclusion: Despite exercising at a lower metabolic heat load, HF patients had a similar increase in Tc but lower SkBF when compared CON. Our results suggest HF patients may have impaired thermoregulation secondary to blunted circulatory heat dissipation in HF.