The measurement and analysis of molecular weight and molecular weight distribution remain matters of fundamental importance for the characterization and physical properties of polymers. Gel permeation chromatography (GPC) is the most routinely used method for the molecular weight determination of polymers whereas matrix-assisted laser…

The mineral acid-catalyzed dehydration of 2-methyl-1-cyclohexanol has been a popular laboratory exercise in second-year organic chemistry for several decades. The dehydration experiment is often performed by organic chemistry students to illustrate Zaitsev's rule. However, sensitive analytical techniques reveal that the results do not entirely…

These spectroscopic experiments investigate polarity and concentration effects on self-association behavior in N-methylacetamide. Inquiry can be limited to the concentration dependence of hydrogen bonding and estimation of dimerization constant (NMR studies) or to the effect of solvent polarity on extent of hydrogen bonding (IR studies). The…

The use of silver in commercial products has proliferated in recent years owing to its antibacterial properties. Food containers impregnated with micro-sized silver promise long food life, but there is some concern because silver can leach out of the plastic and into the stored food. This laboratory experiment gives students the opportunity to…

An experiment has been developed in which the hydrogen-atom abstraction and the coupling of propionitrile, using Fenton's reagent, are investigated. Students learn about the regiochemistry of radical formation, the stereochemistry of product formation, and the interpretation of GC-MS data, in a safe reaction that can be easily completed in one…

Reactive oxygen species such as singlet oxygen have been a major focus of research in medicine. The effect of singlet oxygen on sterols within biological membranes is becoming increasingly more important. Ergosterol, a vitamin D precursor, is one such sterol. The benzoylation of ergosterol and subsequent reaction with singlet oxygen to form an…

A thematic course called "Climate Change: Chemistry and Controversy" was developed for upper-level non-STEM students. This course used the socioscientific context of climate change to teach chemical principles and the nature of science. Students used principles of agnotology (direct study of misinformation) to debunk climate change…

A series of experiments for undergraduate courses (e.g., organic, physical) have been developed in the area of small molecule organic materials. These experiments focus on understanding the electronic and redox properties of a donor-acceptor molecule that is prepared in a convenient one-step microscale reaction. The resulting intensely colored…

Measurements have been added to an old demonstration of chemical equilibria allowing the determination of thermodynamic constants. The experiment allows the students an opportunity to merge qualitative observations associated with Le Chatelier's principle and thermodynamic calculations using graphical techniques. (Contains 4 figures.)

Analysis of halogenated volatile organic compounds (HVOCs) by GC-MS demonstrates the use of instrumentation in the environmental analysis of pollutant molecules and enhances student understanding of stable isotopes in nature. In this experiment, students separated and identified several HVOCs that have been implicated as industrial groundwater…

Brain mitochondrial dysfunction has been proposed as an etiologic factor in autism spectrum disorder (ASD). Proton magnetic resonance spectroscopic imaging ([superscript 1]HMRS) and MRI were used to assess for evidence of brain mitochondrial dysfunction in longitudinal samples of children with ASD or developmental delay (DD), and cross-sectionally…

It has been more than two decades since the copper-oxide high temperature superconductors were discovered. However, building a satisfactory theoretical framework to study these compounds still remains one of the major challenges in condensed matter physics. In addition to the mechanism of superconductivity, understanding the properties of the…

Multibeam interference lithography is investigated as a manufacturing technique for three-dimensional photonic crystal templates. In this research, optimization of the optical setup and the photoresist initiation system leads to a significant improvement of the optical quality of the crystal, as characterized by normal incidence optical…

At technical colleges and secondary-level tech schools, students enrolled in basic electronics labs who have learned about diodes that do rectification are used to seeing power diodes like the 1N4001. When the students are introduced to low-power zener diodes and signal diodes, component identification gets more complex. If the small zeners are…

Purpose: In this study, the authors evaluated the diagnostic value of spectral/cepstral measures to differentiate dysphonic from nondysphonic voices using sustained vowels and continuous speech samples. Methodology: Thirty-two age- and gender-matched individuals (16 participants with dysphonia and 16 controls) were recorded reading a standard…