Publications by authors named "Tim Gillece"

2 Publications

  • Page 1 of 1

Hydrophobically Modified Isosorbide Dimethacrylates as a Bisphenol-A (BPA)-Free Dental Filling Material.

Materials (Basel) 2021 Apr 22;14(9). Epub 2021 Apr 22.

Interdisciplinary Program in Materials Science and Engineering, New Jersey Institute of Technology, Newark, NJ 07012, USA.

A series of bio-based hydrophobically modified isosorbide dimethacrylates, with , , and benzoate aromatic spacers (ISBGBMA), are synthesized, characterized, and evaluated as potential dental restorative resins. The new monomers, isosorbide 2,5-bis(4-glyceryloxybenzoate) dimethacrylate (ISB4GBMA), isosorbide 2,5-bis(3-glyceryloxybenzoate) dimethacrylate (ISB3GBMA), and isosorbide 2,5-bis(2-glyceryloxybenzoate) dimethacrylate (ISB2GBMA), are mixed with triethylene glycol dimethacrylate (TEGDMA) and photopolymerized. The resulting polymers are evaluated for the degree of monomeric conversion, polymerization shrinkage, water sorption, glass transition temperature, and flexural strength. Isosorbide glycerolate dimethacrylate (ISDGMA) is synthesized, and Bisphenol A glycerolate dimethacrylate (BisGMA) is prepared, and both are evaluated as a reference. Poly(ISBGBMA/TEGDMA) series shows lower water sorption (39-44 µg/mm) over Poly(ISDGMA/TEGDMA) (73 µg/mm) but higher than Poly(BisGMA/TEGDMA) (26 µg/mm). Flexural strength is higher for Poly(ISBGBMA/TEGDMA) series (37-45 MPa) over Poly(ISDGMA/TEGDMA) (10 MPa) and less than Poly(BisGMA/TEGDMA) (53 MPa) after immersion in phosphate-buffered saline (DPBS) for 24 h. Poly(ISB2GBMA/TEGDMA) has the highest glass transition temperature at 85 °C, and its monomeric mixture has the lowest viscosity at 0.62 Pa·s, among the (ISBGBMA/TEGDMA) polymers and monomer mixtures. Collectively, this data suggests that the ortho ISBGBMA monomer is a potential bio-based, BPA-free replacement for BisGMA, and could be the focus for future study.
View Article and Find Full Text PDF

Download full-text PDF

Source Listing
April 2021

Influence of various environmental parameters on sweat gland activity.

J Cosmet Sci 2013 Jul-Aug;64(4):243-60

Department of Materials Science, Corporate R&D, Ashland Specialty Ingredients, Wayne, NJ, USA.

The choice of environmental conditions when conducting antiperspirant studies greatly affects the quantity of sweat output. Our initial goal in this work was to develop an in-house procedure to test the efficacy of antiperspirant products using replica techniques in combination with image analysis. To ameliorate the skin replica method, we conducted rheological studies using dynamic mechanical analysis of the replica formulation. In terms of sweat output quantification, our preliminary results revealed a considerable amount of variation using the replica technique, leading us to conduct more fundamental studies of the factors that influence sweating behavior and how to best design the experimental strategy. In accordance with the FDA's protocol for antiperspirant testing, we carried out gravimetric analyses of axillae sweating under a variety of environmental conditions including temperature and humidity control. Subjects were first acclimatized in an environmentally controlled room for 30 min, and then placed in a sauna for an additional 30 or 45 min, depending on which test we administered. In Test 1 (30 min total in the sauna), the first 10 min in the sauna was another equilibration period, followed by a 20 min sweat production stage. We monitored axillae sweating during the last 20 min in the sauna by gravimetric analysis. At time (t) = 30 min in the sauna, skin replicas were taken and later analyzed using imaging and image analysis techniques. Test 1 was carried out on over 25 subjects, both male and female, from various racial backgrounds. In Test 2, subjects spent 45 min in the sauna after the initial 30-min period in the environmental room. During the 45 min, we obtained gravimetric readings of absorbent pads placed in the axillae. We conducted studies at various temperature and relative humidity settings. We also studied the influence of several external parameters on sudoriferous activity. Test 2 was a range-finding experiment on two subjects to determine the optimized environmental conditions for the hot room procedure. In addition to the replica and gravimetric techniques, we also measured flux density to determine the onset of firing of sweat glands to ensure that our environmental preconditioning step (30 min in the environmental room) brought subjects to the point that their sweat glands were activated. Although flux density measurements are usually carried out to determine transepidermal water loss (TEWL), we found that they can be equally useful for monitoring the onset of sweat production. Thermal infrared imaging experiments were also carried out allowing us to generate full-body images of subjects containing anatomical thermal distribution data with high accuracy. Overall, we conclude that our in-house hot room procedure offers much potential as an effective and cost-efficient screening tool for narrowing copious antiperspirant formulations to a select few for expensive clinical evaluation.
View Article and Find Full Text PDF

Download full-text PDF

September 2013