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Three aldohexose monosaccharides, d-glucose, d-mannose, and d-galactose, were examined by scanning temperature dielectric analysis (DEA) from ambient temperatures through their melts. Phase transitions, including glass transition (T g) and melting temperature (T m), were evaluated by differential scanning calorimetry (DSC). The monosaccharides were found to exhibit thermally-induced dielectric loss spectra in their amorphous-solid phase before melting. Activation energies for electrical charging of each of the monosaccharides were calculated from an Arrhenius plot of the tan delta (e″/e′, dielectric loss factor/relative permittivity) peak frequency versus reciprocal temperature in Kelvin. The DEA profiles were also correlated with the DSC phase diagrams, showing the changes in electrical behavior associated with solid–solid and solid–liquid transitions.

Advances in science and technology are now at the heart of the global economy, but the number of students earning degrees in the sciences, technology, engineering, and math (STEM) fields has stalled. According to the National Association for Colleges and Employers (NACE), programs have been initiated nationwide to nurture interest in the sciences, including research competitions, co-ops and internships, and K-12 STEM education. Senior thermal analysis scientists are not only researchers, they are role models, mentors and teachers intimately involved in the recruitment and training of young scientists. The authors present guidelines for thermal analysis research project planning for high school students, undergraduate students and master’s and doctoral candidates. Project planning includes developmentally appropriate techniques, methods, instruments, scope and significance. Case studies illustrate examples of short-term, concrete materials analysis projects tailored to younger student researchers, as well as master’s level projects making significant contributions to the state of the science and innovative doctoral research. In addition to designing projects for students at all levels, senior thermal analysis scientists can use specific teaching and training techniques to help young scientists develop their abilities in the lab and at the podium.

Novel dielectric behavior of a linear increase in ionic conductivity prior to melt temperature was observed for active pharmaceutical ingredients (APIs), organic chemicals, amino acids, and carbohydrates. Though, there are solids like polyolefins and long chain organic compounds (tetracosane, pentacosane) which do not exhibit this premelt behavior (i.e., the temperature where the onset of increase in ionic conductivity to melt temperature). We have discovered novel electrical conductivity properties and other physical analytical variations which can lead to unique synthetic routes of certain chemical entities. The above-mentioned unique variations are not related to solid–solid transitions which are quite often observed in pharmaceutical crystalline solids. These new properties are related to amorphous crystalline behavior of a solid. We have also studied the effect of various experimental variables: such as amount of mass tested, applied frequency at a given electric field and heating rate, which results in varying the onset temperature of the increase in ionic conductivity. Melting of the solids was correlated using differential scanning calorimetry (DSC). Activation energies for all the solids were measured in the premelt region using an Arrhenius plot at a specific frequency since we observed changes in the conductivity with frequency. This study focused on frequencies 0.1 to 10 Hz, since the conductivity at these frequencies related to surface analysis. This new physical properties are leading to new electro synthetic procedures to modify or prepare chemicals.

Three electrorheological fluids (ERFs) of recently synthesized Polyaniline.HCl and Cellulose fluids as well as a commercial product from Fludicon® (Germany), were evaluated with a two-electrode probe unit and by Dielectric Analysis (DEA). The study was a part of an ongoing medical device development project. The dielectric response times were calculated using the critical peak frequency in a corresponding Debye plot of Tan Delta (loss factor/permittivity) vs. log frequency. The DEA revealed the response times (tau, τ) in ms. The Fludicon® ERF was DEA durable (repeat cycles produced same results) and the τ was temperature dependent: 16 ms at 25°C and 0.16 ms at 80°C. The Cellulose ERF was somewhat DEA durable and the τ was 5.5 ms at 25°C and 0.21 ms at 80°C. The response times were logarithmic with the temperature (°C) with a correlation coefficient of >0.98 for the Cellulose and Fludicon® ERFs. The Polyaniline ERF had a τ of 53 ms at 25°C in the 1st DEA run and there was no indication of a τ for the remaining DEA tests.

Eugenol is the main volatile compound extracted oil from clove bud, Syzygium aromaticum L., and used in traditional medicine, as a bactericide, fungicide, anesthetic, and others. Its extraction was performed using hydrodistillation which is the most common extraction technique. Its components and thermal behavior were evaluated using gas chromatography (GC) and differential scanning calorimetry (DSC), which provide a better characterization of these natural compounds. This extracted product was compared to the standard eugenol results. The GC results suggested ~90% eugenol was found in the total extracted oil, and some of its boiling characteristics were 270.1 °C for peak temperature and 244.1 J g−1 for the enthalpy variation.

Dielectric Thermal Analysis (DETA) of drugs, proteins and amino acids reveals a strongly linear conductivity increase prior to and peaking at the melt, associated with dielectric viscoelastic properties of the material. Premelt onset and peak are shown to depend on thermal history. Comparisons of neat amino acid samples to samples heated to 150 °C; dried in a desiccator; or heated above their melting point and cooled show significant premelt and melt shifts. Melts are also correlated with phase transitions observed by Differential Scanning Calorimetry (DSC). Activation energies attributed to charging in the premelt for amino acids were typically 250 J/mole.

Eugenol is an allyl chain-substituted guaiacol in the biosynthesized phenylpropanoid compound class derived from Syzygium aromaticum L. and widely used in folk medicine. Nonetheless, its pharmacological use is limited by some problems, such as instability when exposed to light and high temperature. In order to enhance stability, the eugenol molecule was structurally modified, resulting in eugenyl acetate. The eugenyl acetate’s thermal behavior and crystal structure was then characterized by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) and compared to a commercial sample.

This biomaterials overview for selecting polymers for medical devices focuses on polymer materials, properties and performance. An improved understanding of thermoplastics and thermoset properties is accomplished by thermal analysis for device applications. The medical applications and requirements as well as the oxidative and mechanical stability of currently used polymers in devices are discussed. The tools used to aid the ranking of the thermoplastics and thermosets are differential scanning calorimetry (DSC), thermogravimetry (TG), thermal mechanical analysis (TMA) and dynamic mechanical analysis (DMA) as well as a number of key ASTM polymer tests. This paper will spotlight the thermal and mechanical characterization of the bio-compatible polymers e.g., olefins, nylon, polyacetals, polyvinyl chloride and polyesters.

A 16-yr-old northern water snake (Nerodia sipedon) presented with a large, firm midcoelomic swelling. A complete blood count, survey radiographs, coelomic ultrasound, and fine needle aspirate of the mass were performed. Survey radiographs revealed a soft tissue opacity mass. Ultrasonographic examination confirmed the presence of the mass but could not aid in its visceral localization. After 2 weeks, the snake presented again because of continued anorexia and poor quality of life. Euthanasia was performed. Gross necropsy revealed a multilobulated mass attached to and effacing the splenopancreas. Histologically, the mass was composed of cuboidal to columnar neoplastic epithelial cells forming tubules surrounded by variable amounts of fibrovascular stroma. Histological examination and immunohistochemical staining of other tissues revealed local invasion in the subserosa and tunica muscularis of the stomach, metastasis within the liver, in the mesovarium, and an intravascular metastasis within the ventricle of the heart surrounded by a thrombus.

Iontophoretic and electroporation transdermal delivery modes of ionic drugs have been utilized in a number of clinical and biomedical devices. However, applications of these methods have been found challenging for the delivery of many non polar and high molecular weight clinically important drugs. The main goal of the present study is to investigate whether transdermal transport of non polar macromolecular drugs such as insulin and terbinafine can be safely enhanced as a result of their polarization and activation by AC electrokinetic forces. An in vitro delivery system was developed to simulate a clinical application, where transdermal non invasive delivery of medication through a biological membrane is motivated by a combination of AC electrokinetic and AC iontophoresis protocols generated on a device located external to the membrane. The developed method resulted in an average transdermal delivery of 57% of insulin and 39% of terbinafine during several minutes long delivery cycle, which is at least an order of magnitude improvement over the results reported for these drugs in the literature for various passive and active transdermal delivery protocols. For the proposed drug delivery model quantification of the amounts of transported drugs and their relationship to experimental parameters, such as AC voltage amplitude and frequency, treatment time, and membrane thickness were investigated. Experimental results validated a computational model simulating the effects of major electrokinetic forces on drug particle in non uniform AC electric field. The presented transdermal approach overcomes many limitations of existing drug delivery technologies, providing efficient, regulated, localized, non invasive and safe delivery method for high molecular weight non polar macromolecules such as insulin.

A 307-bp Sau3AI fragment previously cloned by deletion enrichment from the bovine Y chromosome was used to isolate a larger lambda EMBL3A genomic cattle clone. The whole 13-kb insert did not give a sex-specific pattern of hybridization to Southern blots of cattle DNA. Subclones from this phage, however, did show that this fragment had a Y-chromosomal origin. It was estimated that at least 40% of the cattle Y chromosome is composed of repeated sequences related to those within these subcloned fragments. Sequences within these subclones are male-specific or male-enriched also in sheep, goats, and deer. Comparison of cattle and sheep homologues of these sequences reveals that much greater amplification and rearrangement have occurred on the cattle Y chromosome than on the sheep Y. The apparent insertion of sequences into cattle Y-specific sequences relative to the sheep homologues suggests possible mechanisms for the evolution of the artiodactyl Y chromosome.