Kevin A. Schug’s research while affiliated with The University of Texas at Arlington and other places

Introduction Waterpipe (WP) tobacco smoking remains popular among US young adults, yet specific regulations for WP devices are lacking. This study examines how WP device size (base volume and height) affects smoking behavior, toxicant exposures, and subjective experiences. Methods Thirty-eight individuals who smoke WP aged 21 to 39 participated in a randomized crossover study. Each completed three 45-minute ad libitum smoking sessions using small, medium, and large WP sizes. Saliva nicotine and exhaled carbon monoxide (eCO) were measured before and after smoking. Puff topography was recorded during sessions, and subjective smoking experiences were collected afterward. Results Significant differences were observed in saliva nicotine between the three WP sizes, with higher concentrations for the small WP relative to larger sizes (Ps<0.05). Exhaled CO was significantly higher after smoking the large WP compared to smaller sizes (Ps<0.05). Puff topography revealed significant differences and followed a dose-response pattern, with larger size associated with longer puff duration, greater smoke volume inhaled, and larger puff volume (Ps<0.05). The large WP was associated with enhanced subjective experiences for satisfaction and concentration compared to the small WP (Ps<0.05). Conclusions WP size substantially impacts smoking experiences and exposures. Regulation of WP size should be essential in comprehensive tobacco control policies aimed at curbing WP use among young adults. These findings will aid in developing of WP size-specific standards to regulate the marketing and sales of WP devices. Such regulations should aim to minimize toxicant exposure by controlling the dimensions and design of WP components, which can significantly influence smoking behavior and toxicant intake. Implications This study underscores the critical role of waterpipe (WP) size in shaping smoking behavior, experiences, and exposures among young adults.

A commercially available dielectric barrier discharge ionization (DBDI) source was tested with supercritical fluid chromatography‐mass spectrometry (SFC‐MS). The compound mixture investigated comprised caffeine, theobromine, theophylline, uracil, testosterone, and pyrene, diluted in methanol. Dynamic response ranges were evaluated with multiple injections at different concentrations. Precision studies demonstrated the robustness and sensitivity of the ionization source across a concentration range of 10–1000 ng/mL. Results from this experiment showed linear regression of 0.99 or greater for all analytes tested over the range with a relative standard deviation (RSD) of less than 10% down to 10 ng/mL for all analytes except theobromine, which had an RSD of less than 10% down to 25 ng/mL. Notably, this study marks the first investigation of sensitivity for coupling a commercial DBDI source with SFC; a limit of detection less than 1 ng/mL was achieved for all compounds. This study demonstrates chromatographic separation by SFC and MS analysis for compounds that ionize poorly using traditional atmospheric pressure ionization, such as polycyclic aromatic hydrocarbons. Combining SFC with the DBDI source opens promising avenues for analyzing compounds that were previously challenging to characterize with standard atmospheric pressure ionization techniques.

Vacuum‐assisted headspace solid‐phase microextraction (Vac‐HS‐SPME) is a technique used to enhance SPME sampling of semi‐volatile organic compounds. Here, it was combined with a high‐capacity SPME Arrow, which features a larger volume of extraction phase and a more rugged configuration than traditional extraction fibers. An in‐depth assessment of the critical parameters was conducted to achieve optimal extraction of representative compounds from a model solid sample matrix (Ottawa sand). Operational fundamentals investigated included the types of seals needed to create a leak‐free environment under vacuum conditions; the magnitude of the vacuum applied and time needed to activate the Vac kinetics; order of sample vial preparation methods (VPMs); and other standard variables associated with extract analysis by gas chromatography‐mass spectrometry. When exploring the limits of sample VPMs, results indicated an ideal workflow requires the solid sample to be spiked before sealing the vial, allow the sample to rest overnight, then apply vacuum at a pressure of ‐677 mbar (out of ‐789 mbar maximum possible vacuum with pump and compressor used), exerted on the vial for 90 s. This work provides the necessary workflow for the optimization of Vac‐HS‐SPME sampling of analytes from solid matrices.

Citation: Sanchez-Rosario, R.; Garcia, J.; Rodriguez, V.; Schug, K.A.; Hildenbrand, Z.L.; Bernal, R.A. Using Bacteriophages to Treat Resilient Bacteria Found in Produced Water. Water 2024, 16, 797. https:// Abstract: Numerous treatment modalities have been employed over the years to eradicate bacterial communities in industrial wastewater. Oxidizing agents and chemical additives, such as ozone, permanganate, glutaraldehyde, and chlorine, are effective in treating microbial contaminants that are typically found in domestic wastewater. However, the chemical complexity of water produced from fracking requires novel approaches, because the microbes have developed mechanisms to overcome typical disinfectants. In this work, we test the effectiveness of bacteriophages for the eradication of two model bacteria from produced water: Pseudomonas aeruginosa and Bacillus megaterium. These bacteria were grown in low salinity produced water and exposed to their corresponding phage. Overall, the total inactivation of the P. aeruginosa population was achieved, as well as the inactivation of B. megaterium. These promising results provide a potentially useful tool for bacterial elimination in overall PW treatment, at an industrial scale. Particularly, since phage treatment is a rapid and cost-effective alternative. Moreover, these results fall within the objectives proposed as part of the sustainable development goals adopted worldwide.

Vacuum-assisted headspace solid-phase microextraction (Vac-HS-SPME) is an emerging sampling technique that enhances the extraction of semi-volatile compounds. The one extra step of pulling vacuum from the sampling vial pre-equilibrium increases the concentration of semi-volatiles in the headspace and allows for faster extraction times. This overview highlights the timeline, applications, and fundamentals of Vac-HS-SPME.

Untargeted analysis using liquid chromatography with tandem mass spectrometry (LC–MS/MS) chemical profiling has become a valuable tool for providing insight into the variations found in a sample set. However, the large data sets often generated, frequently yielding upwards of 20,000 features or more, can be overwhelming. Key elements in creating an experimental design are one of the most pivotal aspects of verifying statistical variance in a sample set. Therefore, care should be taken when an experimental design is developed and when statistical tools are used to perform data reduction and processing.