The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Fred W Kolkhorst - One of the best experts on this subject based on the ideXlab platform.
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effect of skin temperature on the cholinergic sensitivity of the human eccrine sweat gland
Japanese Journal of Physiology, 2003Co-Authors: Dana M Dipasquale, Michael J Buono, Fred W KolkhorstAbstract:Although sweat gland activity is directly controlled by the central nervous system, which detects changes in core body temperature, sweat glands can also be influenced by local cutaneous thermal conditions. Objective: The present study sought to determine the effect of local skin temperature on pilocarpine-induced sweating within a range of typical skin temperatures. Methods: Thirteen subjects (30 ± 6 years; 172 ± 11 cm; 72.8 ± 11.0 kg) had forearm sweat rates measured at rest following pilocarpine iontophoresis at each of three skin temperatures in randomized order: warm (Twarm = 37.1 ± 0.9°C), control (Tcon = 32.3 ± 1.4°C), and cool (Tcool = 26.6 ± 1.3°C). Tskin was raised and lowered with an electric Heating Pad and gel ice pack, respectively. Forearm Tskin was measured with a skin temperature probe. Pilocarpine iontophoresis was used on an approximately 7 cm2 area of the anterior forearm to stimulate localized sweating. Following stimulation, sweat was collected from the area for 15 min with a Macroduct Sweat Collection System. Results: There was a higher sweat rate at Twarm (p = 0.001) and Tcon (p = 0.006) compared to that at Tcool. However, there was no difference between the sweat rate at Twarm and that at Tcon (p = 0.127). Conclusion: These results indicated that skin temperatures below approximately 32°C affect local sweat production primarily by altering glandular sensitivity to the neurotransmitter, whereas skin temperatures above approximately 32°C predominantly affect neurotransmitter release. Furthermore, sweat glands display maximal or near maximal cholinergic sensitivity at resting skin temperature in a thermoneutral environment.
Thomas De Beer - One of the best experts on this subject based on the ideXlab platform.
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modelling the primary drying step for the determination of the optimal dynamic Heating Pad temperature in a continuous pharmaceutical freeze drying process for unit doses
International Journal of Pharmaceutics, 2017Co-Authors: Laurens De Meyer, Joris Lammens, Severine Therese F C Mortier, Brecht Vanbillemont, Pieterjan Van Bockstal, Jos Corver, Ingmar Nopens, Chris Vervaet, Thomas De BeerAbstract:Abstract In the pharmaceutical industry, traditional freeze-drying of unit doses is a batch-wise process associated with many disadvantages. To overcome these disadvantages and to guarantee a uniform product quality and high process efficiency, a continuous freeze-drying process is developed and evaluated. The main differences between the proposed continuous freeze-drying process and traditional freeze-drying can be found firstly in the freezing step during which the vials are rotated around their longitudinal axis (spin freezing), and secondly in the drying step during which the energy for sublimation and desorption is provided through the vial wall by conduction via an electrical Heating Pad. To obtain a more efficient drying process, the energy transfer has to be optimised without exceeding the product and process limits (e.g. cake collapse, choked flow). Therefore, a mechanistic model describing primary drying during continuous lyophilisation of unit doses based on conduction via Heating Pads was developed allowing the prediction of the optimal dynamic power input and temperature output of the electric Heating Pads. The model was verified by experimentally testing the optimal dynamic primary drying conditions calculated for a model formulation. The primary drying endpoint of the model formulation was determined via in-line NIR spectroscopy. This endpoint was then compared with the predicted model based endpoint. The mean ratio between the experimental and model based predicted drying time for six verification runs was 1.05 ± 0.07, indicating a good accordance between the model and the experimental data.
Matthew D. Phaneuf - One of the best experts on this subject based on the ideXlab platform.
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Use of textile dyeing technology to create an infection-resistant functionalized polyester biomaterial
Journal of Biomedical Materials Research - Part B Applied Biomaterials, 2010Co-Authors: P. Aggarwal, Kerry A. Sousa, Martin J Bide, Frank W. Logerfo, Matthew D. PhaneufAbstract:Infection is a major complication when utilizing implantable devices. The purpose of this study was to create a functionalized polyethylene terephthalate (polyester) biomaterial with sustained antimicrobial properties using textile-dyeing technology. Polyester was hydrolyzed via exposure to sodium hydroxide (NaOH) to provide two functional sites within the polymeric backbone. A modified textile dyeing technique known as thermofixation or Pad-Heating (Pad-heat) in conjunction with autoclaving was employed to directly incorporate the fluoroquinolone antibiotic Ciprofloxacin (Cipro) into polyester fibers. Woven polyester segments were placed into various concentrations of boiling NaOH solutions to create carboxylic acid and hydroxyl groups (HYD). The segments were then sprayed (Padded) with a 5 mg mL(-1) Cipro solution and dried overnight, followed by exposure to intense heat and autoclaving. Untreated HYD, Cipro-dipped, and Pad-heat-treated HYD segments were then washed under stringent conditions. The antimicrobial activity of the each material was determined via zone of inhibition. Untreated HYD controls had no antimicrobial activity at any of the time periods examined. Cipro-dipped HYD segments had no antimicrobial activity after 1 h. In contrast, antimicrobial activity for autoclaved, Pad-heat-treated HYD segments persisted for 80 days (length of study). Autoclave usage prior to plating affected antimicrobial activity substantially. Additionally, varying hydrolysis concentrations did not significantly affect overall Cipro release. Thus, Cipro application to HYD polyester via thermofixation resulted in controlled, sustained antibiotic release over an extended period of time. The long-term infection resistance provided by this technique may address major problems of infection from which implantable devices suffer.
Dana M Dipasquale - One of the best experts on this subject based on the ideXlab platform.
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effect of skin temperature on the cholinergic sensitivity of the human eccrine sweat gland
Japanese Journal of Physiology, 2003Co-Authors: Dana M Dipasquale, Michael J Buono, Fred W KolkhorstAbstract:Although sweat gland activity is directly controlled by the central nervous system, which detects changes in core body temperature, sweat glands can also be influenced by local cutaneous thermal conditions. Objective: The present study sought to determine the effect of local skin temperature on pilocarpine-induced sweating within a range of typical skin temperatures. Methods: Thirteen subjects (30 ± 6 years; 172 ± 11 cm; 72.8 ± 11.0 kg) had forearm sweat rates measured at rest following pilocarpine iontophoresis at each of three skin temperatures in randomized order: warm (Twarm = 37.1 ± 0.9°C), control (Tcon = 32.3 ± 1.4°C), and cool (Tcool = 26.6 ± 1.3°C). Tskin was raised and lowered with an electric Heating Pad and gel ice pack, respectively. Forearm Tskin was measured with a skin temperature probe. Pilocarpine iontophoresis was used on an approximately 7 cm2 area of the anterior forearm to stimulate localized sweating. Following stimulation, sweat was collected from the area for 15 min with a Macroduct Sweat Collection System. Results: There was a higher sweat rate at Twarm (p = 0.001) and Tcon (p = 0.006) compared to that at Tcool. However, there was no difference between the sweat rate at Twarm and that at Tcon (p = 0.127). Conclusion: These results indicated that skin temperatures below approximately 32°C affect local sweat production primarily by altering glandular sensitivity to the neurotransmitter, whereas skin temperatures above approximately 32°C predominantly affect neurotransmitter release. Furthermore, sweat glands display maximal or near maximal cholinergic sensitivity at resting skin temperature in a thermoneutral environment.
Laurens De Meyer - One of the best experts on this subject based on the ideXlab platform.
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modelling the primary drying step for the determination of the optimal dynamic Heating Pad temperature in a continuous pharmaceutical freeze drying process for unit doses
International Journal of Pharmaceutics, 2017Co-Authors: Laurens De Meyer, Joris Lammens, Severine Therese F C Mortier, Brecht Vanbillemont, Pieterjan Van Bockstal, Jos Corver, Ingmar Nopens, Chris Vervaet, Thomas De BeerAbstract:Abstract In the pharmaceutical industry, traditional freeze-drying of unit doses is a batch-wise process associated with many disadvantages. To overcome these disadvantages and to guarantee a uniform product quality and high process efficiency, a continuous freeze-drying process is developed and evaluated. The main differences between the proposed continuous freeze-drying process and traditional freeze-drying can be found firstly in the freezing step during which the vials are rotated around their longitudinal axis (spin freezing), and secondly in the drying step during which the energy for sublimation and desorption is provided through the vial wall by conduction via an electrical Heating Pad. To obtain a more efficient drying process, the energy transfer has to be optimised without exceeding the product and process limits (e.g. cake collapse, choked flow). Therefore, a mechanistic model describing primary drying during continuous lyophilisation of unit doses based on conduction via Heating Pads was developed allowing the prediction of the optimal dynamic power input and temperature output of the electric Heating Pads. The model was verified by experimentally testing the optimal dynamic primary drying conditions calculated for a model formulation. The primary drying endpoint of the model formulation was determined via in-line NIR spectroscopy. This endpoint was then compared with the predicted model based endpoint. The mean ratio between the experimental and model based predicted drying time for six verification runs was 1.05 ± 0.07, indicating a good accordance between the model and the experimental data.