A Large-Scale, Multiplayer Virtual Reality Deployment: A Novel Approach to Distance Education in Human Anatomy.

The arrival of COVID-19 restrictions and the increasing demand of online instruction options posed challenges to education communities worldwide, especially in human anatomy. In response, Colorado State University developed and deployed an 8-week-long large-scale virtual reality (VR) course to supplement online human anatomy instruction. Students (n = 75) received a VR-capable laptop and head-mounted display and participated in weekly synchronous group laboratory sessions with instructors. The software enabled students to remotely collaborate in a common virtual space to work with human anatomy using an artist-rendered cadaver. Qualitative data were collected on student engagement, confidence, and reactions to the new technology. Quantitative data assessed student knowledge acquisition and retention of anatomical spatial relationships. Results indicated that students performed better in the online course (mean = 82.27%) when compared to previous in-person laboratories (mean = 80.08%). The utilization of VR promoted student engagement and increased opportunities for student interaction with teaching assistants, peers, and course content. Notably, students reported benefits that focused on unique aspects of their virtual learning environment, including the ability to infinitely scale the cadaver and walk inside and around anatomical structures. Results suggested that using VR was equivalent to 2D methods in student learning and retention of anatomical relationships. Overall, the virtual classroom maintained the rigor of traditional gross anatomy laboratories without negatively impacting student examination scores and provided a high level of accessibility, without compromising learner engagement. Supplementary Information: The online version contains supplementary material available at 10.1007/s40670-023-01751-w.

Assessment of burnout and pandemic fatigue among pharmacy leadership in the Veterans Health Administration healthcare system.

PURPOSE: Factors associated with burnout in Veterans Health Administration (VHA) pharmacy leadership positions were examined during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: A questionnaire was distributed to all pharmacy executives of the VHA healthcare system. It collected demographic and employment characteristics, career satisfaction and work-related variables, indicators of burnout using validated single-item measures adapted from the Maslach Burnout Inventory, and the impact of the COVID-19 pandemic on psychosocial and work-related variables. A χ2 test with Bonferroni correction was used to evaluate the data. Burnout was defined as a score of 4 or greater on either of the 2 single-item validated statements adapted from the Maslach Burnout Inventory to assess emotional exhaustion and depersonalization. RESULTS: In total, 407 (of 1,027; 39.6%) VHA pharmacy leaders representing Veterans Integrated Service Network pharmacy executives, chiefs of pharmacy, associate chiefs of pharmacy, and inpatient and outpatient supervisors completed the survey. The overall prevalence of burnout was 68.6% using the aggregate measure of emotional exhaustion or depersonalization. Pharmacy leaders who worked more than 60 hours a week reported significantly greater rates of burnout than those who worked 40 to 60 hours a week (86.7% vs 66.9%, χ2 = 7.34, degrees of freedom = 1, P < 0.05). Those experiencing increased workload related to COVID-19 also reported high burnout rates (72.1%, χ2 = 16.40, degrees of freedom = 1, P < 0.001). Burnout scores were similar across groups when respondents were stratified by leadership position, gender, age, or years in position. CONCLUSION: As of March 2021, two-thirds of pharmacy leaders were experiencing burnout. It is important for healthcare system leadership to identify patterns of burnout among their pharmacy leaders to ensure a productive and sustainable workforce.

Physicochemical and toxicological properties of wood smoke particulate matter as a function of wood species and combustion condition.

Wood burning is a major source of ambient particulate matter (PM) and has been epidemiologically linked to adverse pulmonary health effects, however the impact of fuel and burning conditions on PM properties has not been investigated systematically. Here, we employed our recently developed integrated methodology to characterize the physicochemical and biological properties of emitted PM as a function of three common hardwoods (oak, cherry, mesquite) and three representative combustion conditions (flaming, smoldering, incomplete). Differences in PM and off-gas emissions (aerosol number/mass concentrations; carbon monoxide; volatile organic compounds) as well as inorganic elemental composition and organic carbon functional content of PM0.1 were noted between wood types and combustion conditions, although the combustion scenario exerted a stronger influence on the emission profile. More importantly, flaming combustion PM0.1 from all hardwoods significantly stimulated the promoter activity of Sterile Alpha Motif (SAM) pointed domain containing ETS (E-twenty-six) Transcription Factor (SPDEF) in human embryonic kidney 293 (HEK-293 T) cells, a biomarker for mucin gene expression associated with mucus production in pulmonary diseases. However, no bioactivity was observed for smoldering and incomplete combustion, which was likely driven by differences in the organic composition of PM0.1. Detailed chemical speciation of organic components of wood smoke is warranted to identify the individual compounds that drive specific biological responses.

Development of an Integrated Platform to Assess the Physicochemical and Toxicological Properties of Wood Combustion Particulate Matter.

Wood burning contributes to indoor and ambient particulate matter (PM) pollution and has been associated with increased morbidity and mortality. Here, we present an integrated methodology that allows to generate, sample, and characterize wood smoke derived from different moisture contents and representative combustion conditions using pine wood as a model. Flaming, smoldering, and incomplete combustion were assessed for low-moisture pine, whereas both low-moisture pine and high-moisture pine were investigated under flaming conditions. Real-time monitoring of carbon monoxide, volatile organic compounds, and aerosol number concentration/size in wood smoke was performed. The PM was size-fractionated, sampled, and characterized for elemental/organic carbon, organic functional groups, and inorganic elements. Bioactivity of PM was assessed by measuring the sterile alpha motif (SAM) pointed domain containing ETS (E-twenty-six) transcription factor (SPDEF) gene promoter activity in human embryonic kidney 293 (HEK-293T) cells, a biomarker for mucin gene expression. Findings showed that moisture content and combustion condition significantly affected the organic and inorganic elemental composition of PM0.1 as well as its bioactivity. Also, for a given moisture and combustion scenario, PM chemistry and bioactivity differed considerably with PM size. Importantly, PM0.1 from flaming combustion of low-moisture pine contained the highest abundance of the oxygenated saturated aliphatic functional group [H-C-O] and was also biologically most potent in stimulating SPDEF promoter activity, suggesting the role of organic compounds such as carbohydrates and sugar alcohols (that contain [H-C-O]) in driving mucus-related respiratory outcomes. Our platform enables further well-controlled parametric studies using a combination of in vitro and in vivo approaches to link wood burning parameters with acute and chronic inhalation health effects of wood smoke.

Exploring the Association Between Antibiotic Prescribing Patterns and Clinical Variations in a Network of Pediatricians.

INTRODUCTION: Variation in practice patterns among physicians is well-documented despite professional guidelines and increasingly uniform medical training. Variations may lead to improper utilization of healthcare resources, misdiagnosis, overdiagnosis, unnecessary treatments, and forgoing of needed interventions. One area of clinical variation and overuse of particular interest is the prescribing of antibiotics, which can lead to eventual antibiotic resistance and other negative consequences. Variations in antibiotic prescribing along with other practice patterns have been studied previously but no attempt has been made to examine the correlation between multiple practice patterns. The purpose of this study was to determine if a correlation existed between the provider behaviors studied. METHODS: A small area network of 39 pediatric providers was analyzed to determine if antibiotic prescription percentages varied. Antibiotic prescription percentages were further broken down by visit type (sick versus well). Two other practice measures, in-office lab utilization and diagnoses of food and drug allergies, were then analyzed. Data were explored primarily with Spearman's correlation tests. RESULTS: Strong positive correlation was seen between a provider's antibiotic prescription percentage at sick and well visits. Strong positive correlation was seen between the antibiotic prescribing percentage and the number of in-office labs ordered. Moderate positive correlation was seen between antibiotic prescribing percentage and the percentage of a provider's empaneled patients with any allergy diagnosis (medication, food, or seasonal). CONCLUSION: This retrospective study demonstrates that variation in provider practice patterns continues to exist despite established practice guidelines from national organizations. It also demonstrates a linear correlation between multiple provider behaviors that have not previously been explored together. The presence of a correlation between clinical behaviors may suggest an underlying practice philosophy and present an opportunity for personalized, provider-specific education and quality improvement.

Immersive 3-Dimensional Virtual Reality Modeling for Case-Specific Presurgical Discussions in Cerebrovascular Neurosurgery.

BACKGROUND: Adequate surgical planning includes a precise understanding of patient-specific anatomy and is a necessity for neurosurgeons. Although the use of virtual reality (VR) technology is emerging in surgical planning and education, few studies have examined the effectiveness of immersive VR during surgical planning using a modern head-mounted display. OBJECTIVE: To investigate if and how immersive VR aids presurgical discussions of cerebrovascular surgery. METHODS: A multiuser immersive VR system, BananaVisionTM, was developed and used during presurgical discussions in a prospective patient cohort undergoing cerebrovascular surgery. A questionnaire/interview was administered to multiple surgeons after the surgeries to evaluate the effectiveness of the VR system compared to conventional imaging modalities. An objective assessment of the surgeon's knowledge of patient-specific anatomy was also conducted by rating surgeons' hand-drawn presurgical illustrations. RESULTS: The VR session effectively enhanced surgeons' understanding of patient-specific anatomy in the majority of cases (83.3%). An objective assessment of surgeons' presurgical illustrations was consistent with this result. The VR session also effectively improved the decision-making process regarding minor surgical techniques in 61.1% of cases and even aided surgeons in making critical surgical decisions about cases involving complex and challenging anatomy. The utility of the VR system was rated significantly higher by trainees than by experts. CONCLUSION: Although rated as more useful by trainees than by experts, immersive 3D VR modeling increased surgeons' understanding of patient-specific anatomy and improved surgical strategy in certain cases involving challenging anatomy.

Characterization of exhaled breath condensate (EBC) non-exchangeable hydrogen functional types and lung function of wildland firefighters.

Inhalation of smoke is shown to be associated with adverse respiratory outcomes in firefighters. Due to invasiveness of procedures to obtain airways lining fluid, the immediate responses of the target organ (i.e. lung) are secondarily assessed through biomarkers in blood and urine. The objective of this study was to identify changes in metabolic profile of exhaled breath condensate (EBC) and lung function of firefighters exposed to wildfires smoke. A total of 29 subjects were studied over 16 events; 14 of these subjects provided cross-shift EBC samples. The predominant types of non-exchangeable hydrogen in EBC were saturated oxygenated hydrogen, aliphatic alkyl and allylic. Non-exchangeable allylic and oxygenated hydrogen concentrations decreased in post-exposure EBC samples. Longer exposures were correlated with increased abundance of oxidized carbon in ketones, acids and esters. Post-exposure lung function declines (forced expiratory volume in 1 s (FEV1): 0.08 l, forced vital capacity (FVC): 0.07 l, FEV1/FVC: 0.03 l, peak expiratory flow (PEF): 0.39 l s-1) indicated airways inflammation. They were related to exposure intensity (FEV1 and FVC) and exposure duration (PEF). This study showed that EBC characterization of non-exchangeable hydrogen types by NMR may provide insights on EBC molecular compositions in response to smoke inhalation and facilitate targeted analysis to identify specific biomarkers.

Assessment of pharmacist gender bias: Egalitarianism of the Department of Veterans Affairs.

For the past 2 decades, the earnings gap between genders has narrowed for pharmacists, making it 1 of the smallest for a high-wage profession. Gender bias is reflected in 2 main areas, pay and opportunity. The Department of Veterans Affairs (VA) is the largest integrated health care system in the country, and the authors performed an analysis to see if there was any evidence of gender bias within its pharmacist workforce. The distribution of pharmacists by gender, age, and years of service was examined and whether part-time employment had any impact was also studied. Overall, there is a high degree of gender egalitarianism in terms of pay and opportunity for pharmacists at the VA. The level of step achievement, and thus, pay for men and women, was not associated with gender but rather years of service.

CNOT gate operation on a photogenerated molecular electron spin-qubit pair.

Implementation of the two-qubit controlled-NOT (CNOT) gate is necessary to develop a complete set of universal gates for quantum computing. Here, we demonstrate that a photogenerated radical (spin qubit) pair within a covalent donor-chromophore-acceptor molecule can be used to successfully execute a CNOT gate with high fidelity. The donor is tetrathiafulvalene (TTF), the chromophore is 8-aminonaphthalene-1,8-dicarboximide (ANI), and the acceptor is pyromellitimide (PI). Selective photoexcitation of ANI with a 416 nm laser pulse results in subnanosecond formation of the TTF•+-ANI-PI•- radical (spin qubit) pair at 85 K having a 1.8 µs phase memory time. This is sufficiently long to execute a CNOT gate using a sequence of five microwave pulses followed by a sequence of two pulses that read out all the elements of the density matrix. Comparing these data to a simulation of the data that assumes ideal conditions results in a fidelity of 0.97 for the execution of the CNOT gate. These results show that photogenerated molecular spin qubit pairs can be used to execute this essential quantum gate at modest temperatures, which affords the possibility that chemical synthesis can be used to develop structures to execute more complex quantum logic operations using electron spins.

Stabilizing the Naphthalenediimide Radical within a Tetracationic Cyclophane.

Organic radicals are of importance in developing smart materials that have paramagnetic and/or near-infrared optical properties. Their practical applications, however, are limited by the labile nature of the radicals. Here, we demonstrate that by using a tetracationic cyclophane, namely, cyclobis(4,4'-(1,4-phenylene)bispyridine-p-phenylene) (ExBox4+), to encapsulate a naphthalenediimide (NDI) guest, the redox properties of NDI can be modulated. In organic solvents such as MeCN or DMF, ExBox4+ is able to provide the surrounding Coulombic attraction to the NDI•- radical anion and therefore enhance its stability toward oxidation. In water, NDI•- is prone to dimerization, forming its (NDI•-)2 dimer. Under UV-light irradiation, the (NDI•-)2 dimer is observed to disproportionate and yield the dianionic NDI2-. ExBox4+ is able to encapsulate the NDI•- radical anion and prevent its dimerization, and as a consequence, the radical anion is protected from further reduction in a noncovalent manner. We believe that our strategy of modulating the redox properties of NDI by either host-guest recognition or mechanical interlocking can aid and abet the development of radical-based materials, which could be employed in pursuit of applications in many areas, such as transporting spin and charges.

Quintet-triplet mixing determines the fate of the multiexciton state produced by singlet fission in a terrylenediimide dimer at room temperature.

Singlet fission (SF) is a photophysical process in which one of two adjacent organic molecules absorbs a single photon, resulting in rapid formation of a correlated triplet pair (T1T1) state whose spin dynamics influence the successful generation of uncorrelated triplets (T1). Femtosecond transient visible and near-infrared absorption spectroscopy of a linear terrylene-3,4:11,12-bis(dicarboximide) dimer (TDI2), in which the two TDI molecules are directly linked at one of their imide positions, reveals ultrafast formation of the (T1T1) state. The spin dynamics of the (T1T1) state and the processes leading to uncoupled triplets (T1) were studied at room temperature for TDI2 aligned in 4-cyano-4'-pentylbiphenyl (5CB), a nematic liquid crystal. Time-resolved electron paramagnetic resonance spectroscopy shows that the (T1T1) state has mixed 5(T1T1) and 3(T1T1) character at room temperature. This mixing is magnetic field dependent, resulting in a maximum triplet yield at ∼200 mT. The accessibility of the 3(T1T1) state opens a pathway for triplet-triplet annihilation that produces a single uncorrelated T1 state. The presence of the 5(T1T1) state at room temperature and its relationship with the 1(T1T1) and 3(T1T1) states emphasize that understanding the relationship among different (T1T1) spin states is critical for ensuring high-yield T1 formation from singlet fission.

Hyperbaric oxygen produces a nitric oxide synthase-regulated anti-allodynic effect in rats with paclitaxel-induced neuropathic pain.

Research has demonstrated that hyperbaric oxygen (HBO2) treatment produced relief of both acute and chronic pain in patients and animal models. However, the mechanism of HBO2 antinociceptive effect is still elusive. Based on our earlier findings that implicate NO in the acute antinociceptive effect of HBO2, the purpose of this study was to ascertain whether HBO2-induced antinociception in a chronic neuropathic pain model is likewise dependent on NO. Neuropathic pain was induced in male Sprague Dawley rats by four injections of paclitaxel (1.0 mg/kg, i.p.). Twenty-four hours after the last paclitaxel injection, rats were treated for one day or four consecutive days with 60-min HBO2 at 3.5 atmospheres absolute (ATA). Two days before HBO2 treatment, some groups of rats were implanted with Alzet® osmotic minipumps that continuously infused a selective inhibitor of neuronal NO synthase (nNOS) into the lateral cerebral ventricle for 7 days. Mechanical and cold allodynia were assessed every other day, using electronic von Frey and acetone assays, respectively. Rats in the paclitaxel control group exhibited a mechanical or cold allodynia that was significantly reversed by one HBO2 treatment for mechanical allodynia and four HBO2 treatments for cold allodynic. In rats treated with the nNOS inhibitor, the effects of HBO2 were nullified in the mechanical allodynia test but unaffected in the cold allodynia test. In summary, these results demonstrate that the antiallodynic effect of HBO2 in two different pain tests is dependent on NO in the CNS.

Molecular Russian dolls.

The host-guest recognition between two macrocycles to form hierarchical non-intertwined ring-in-ring assemblies remains an interesting and challenging target in noncovalent synthesis. Herein, we report the design and characterization of a box-in-box assembly on the basis of host-guest radical-pairing interactions between two rigid diradical dicationic cyclophanes. One striking feature of the box-in-box complex is its ability to host various 1,4-disubstituted benzene derivatives inside as a third component in the cavity of the smaller of the two diradical dicationic cyclophanes to produce hierarchical Russian doll like assemblies. These results highlight the utility of matching the dimensions of two different cyclophanes as an efficient approach for developing new hybrid supramolecular assemblies with radical-paired ring-in-ring complexes and smaller neutral guest molecules.

Effect of Electron-Nuclear Hyperfine Interactions on Multiple-Quantum Coherences in Photogenerated Covalent Radical (Qubit) Pairs.

Ultrafast photodriven electron transfer reactions starting from an excited singlet state in an organic donor-acceptor molecule can generate a spin-correlated radical pair (RP) with an initially entangled spin state that may prove useful as a two-qubit pair in quantum information protocols. Here we investigate the effects of modulating electron-nuclear hyperfine coupling by rapidly transferring an electron between two equivalent sites comprising the reduced acceptor of the RP. A covalent electron donor-acceptor molecule including a tetrathiafulvalene (TTF) donor, a 4-aminonaphthalene-1,8-imide (ANI) chromophoric primary acceptor, and an m-xylene bridged cyclophane having two equivalent pyromellitimides (PI2), TTF-ANI-PI2, as a secondary acceptor was synthesized along with an analogous molecule having one pyromellitimide (PI) acceptor, TTF-ANI-PI. Photoexcitation of ANI within each molecule results in sub-nanosecond formation of TTF+•-ANI-PI-• and TTF+•-ANI-PI2-•. The effect of reducing electron-nuclear hyperfine interactions in TTF+•-ANI-PI2-• relative to TTF+•-ANI-PI-• on decoherence of multiple-quantum coherences has been measured by pulse-EPR spectroscopy. This contribution is especially relevant in the absence of modulation of exchange or dipolar interactions, as with the RP at a fixed distance in the molecules in this work. The theoretical prediction of the contribution from an ensemble of hyperfine interactions to decoherence in these RPs is shown to be less than the full width at half-maximum of the quantum beat frequencies measured experimentally. Pulse bandwidth and off-resonant excitation by square microwave pulses are proposed as larger contributors to decoherence in these molecules than the hyperfine interactions, and specific pulse shapes relevant to arbitrary waveform generation are introduced.

Singlet Fission in 9,10-Bis(phenylethynyl)anthracene Thin Films.

Singlet fission (SF) in two or more electronically coupled organic chromophores converts a high-energy singlet exciton into two low-energy triplet excitons, which can be used to increase solar cell efficiency. Many known SF chromophores are unsuitable for device applications due to chemical instability and low triplet state energies. The results described here show that efficient SF occurs in polycrystalline thin films of 9,10-bis(phenylethynyl)anthracene (BPEA), a commercial dye that has singlet and triplet energies of 2.40 and 1.11 eV, respectively, in the solid state. BPEA crystallizes into two polymorphs with space groups C2/ c and Pbcn, which undergo SF with kSFA = (109 ± 4 ps)-1 and kSFB = (490 ± 10 ps)-1, respectively. The high triplet energy and efficient SF evidenced from the 180 ± 20% triplet yield make BPEA a promising candidate for enhancing solar cell performance.

Covalent Radical Pairs as Spin Qubits: Influence of Rapid Electron Motion between Two Equivalent Sites on Spin Coherence.

Ultrafast photodriven electron transfer reactions starting from an excited singlet state in an organic donor-acceptor molecule generate a radical pair (RP) in which the two spins are initially entangled and, in principle, can serve as coupled spin qubits in quantum information science (QIS) applications, provided that spin coherence lifetimes in these RPs are long. Here we investigate the effects of electron transfer between two equivalent sites comprising the reduced acceptor of the RP. A covalent electron donor-acceptor molecule (D-C-A24+) including a p-methoxyaniline donor (D), a 4-aminonaphthalene-1,8-imide chromophoric primary acceptor (C), and a m-xylene bridged cyclophane having two equivalent phenyl-extended viologens (A24+) as a secondary acceptor was synthesized along with the analogous molecule having one phenyl-extended viologen acceptor and a second, more difficult to reduce 2,5-dimethoxyphenyl-extended viologen in a very similar cyclophane structure (D-C-A4+). Photoexcitation of C within each molecule results in subnanosecond formation of D+•-C-A23+• and D+•-C-A3+•. The spin dynamics of these RPs were characterized by time-resolved EPR spectroscopy and magnetic field effects on the RP yield in both CH3CN and CD3CN. The data show that rapid electron hopping within A23+• promotes spin decoherence in D+•-C-A23+• relative to D+•-C-A3+• having a monomeric acceptor, while the interaction of the RP electron spins with the nuclear spins of the solvent have little or no effect on the spin dynamics. These observations provide important information for designing and understanding novel molecular assemblies of spin qubits with long coherence times for QIS applications.

Development of a Pharmacoeconomic Model to Demonstrate the Effect of Clinical Pharmacist Involvement in Diabetes Management.

BACKGROUND: A data collection tool was developed and nationally deployed to clinical pharmacists (CPs) working in advanced practice provider roles within the Department of Veterans Affairs to document interventions and associated clinical outcomes. Intervention and short-term clinical outcome data derived from the tool were used to populate a validated clinical outcomes modeling program to predict long-term clinical and economic effects. OBJECTIVE: To predict the long-term effect of CP-provided pharmacotherapy management on outcomes and costs for patients with type 2 diabetes. METHODS: Baseline patient demographics and biomarkers were extracted for type 2 diabetic patients having > 1 encounter with a CP using the tool between January 5, 2013, and November 20, 2014. Treatment biomarker values were extracted 12 months after the patient's initial visit with the CP. The number of visits with the CP was extracted from the electronic medical record, and duration of visit time was quantified by Current Procedural Terminology codes. Simulation modeling was performed on 3 patient cohorts-those with a baseline hemoglobin A1c of 8% to < 9%, 9% to < 10%, and ≥ 10%-to estimate long-term cost and clinical outcomes using modeling based on pivotal trial data (the Archimedes Model). A sensitivity analysis was conducted to assess the extent to which our results were dependent on assumptions related to program effectiveness and costs. RESULTS: A total of 7,310 patients were included in the analysis. Analysis of costs and events on 2-, 3-, 5-, and 10-year time horizons demonstrated significant reductions in major adverse cardiovascular events (MACEs), myocardial infarctions (MIs), episodes of acute heart failure, foot ulcers, and foot amputations in comparison with a control group receiving usual guideline-directed medical care. In the cohort with a baseline A1c of ≥ 10%, the absolute risk reduction was 1.82% for MACE, 1.73% for MI, 2.43% for acute heart failure, 5.38% for foot ulcers, and 2.03% for foot amputations. The incremental cost-effectiveness ratios for cost per quality-adjusted life-year during the 2-, 3-, 5-, and 10-year time horizons were cost-effective for the cohorts of patients with a baseline A1c of 9% to < 10% and ≥ 10%. CONCLUSIONS: CPs acting as advanced practice providers reduced A1c from baseline for veterans with type 2 diabetes compared with modeled usual care. Archimedes modeling of the A1c reductions projects a decreased incidence of diabetes complications and overall health care spending when compared with modeled usual care. DISCLOSURES: There was no outside funding source or sponsor for this project. None of the authors report any conflicts of interest. The views expressed in this article are those of the authors and do not necessarily reflect the views or policies of the U.S. Department of Veterans Affairs. Preliminary data from this project were previously presented in abstract form at the Academy of Managed Care Pharmacy 27th Annual Meeting and Expo; April 8-10, 2015; in San Diego, California.

Assessing electronic cigarette emissions: linking physico-chemical properties to product brand, e-liquid flavoring additives, operational voltage and user puffing patterns.

Users of electronic cigarettes (e-cigs) are exposed to particles and other gaseous pollutants. However, major knowledge gaps on the physico-chemical properties of such exposures and contradictory data in published literature prohibit health risk assessment. Here, the effects of product brand, type, e-liquid flavoring additives, operational voltage, and user puffing patterns on emissions were systematically assessed using a recently developed, versatile, e-cig exposure generation platform and state-of-the-art analytical methods. Parameters of interest in this systematic evaluation included two brands (A and B), three flavors (tobacco, menthol, and fruit), three types of e-cigs (disposable, pre-filled, and refillable tanks), two puffing protocols (4 and 2 s/puff), and four operational voltages (2.2-5.7 V). Particles were generated at a high number concentration (106-107 particles/cm3). The particle size distribution was bi-modal (∼200 nm and 1 µm). Furthermore, organic species (humectants propylene glycol and glycerin, nicotine) that were present in e-liquid and trace metals (potassium and sodium) that were present on e-cig heating coil were also released into the emission. In addition, combustion-related byproducts, such as benzene and toluene, were also detected in the range of 100-38,000 ppbv/puff. Parametric analyzes performed in this study show the importance of e-cig brand, type, flavor additives, user puffing pattern (duration and frequency), and voltage on physico-chemical properties of emissions. This observed influence is indicative of the complexity associated with the toxicological screening of emissions from e-cigs and needs to be taken into consideration.

Tunable Crystallinity and Charge Transfer in Two-Dimensional G-Quadruplex Organic Frameworks.

DNA G-quadruplex structures were recently discovered to provide reliable scaffolding for two-dimensional organic frameworks due to the strong hydrogen-bonding ability of guanine. Herein, 2,7-diaryl pyrene building blocks with high HOMO energies and large optical gaps are incorporated into G-quadruplex organic frameworks. The adjustable substitution on the aryl groups provides an opportunity to elucidate the framework formation mechanism; molecular non-planarity is found to be beneficial for restricting interlayer slippage, and the framework crystallinity is highest when intermolecular interaction and non-planarity strike a fine balance. When guanine-functionalized pyrenes are co-crystallized with naphthalene diimide, charge-transfer (CT) complexes are obtained. The photophysical properties of the pyrene-only and CT frameworks are characterized by UV/Vis and steady-state and time-resolved photoluminescence spectroscopies, and by EPR spectroscopy for the CT complex frameworks.

Influence of maternal age on the effects of seleno-l-methionine in the model organism Daphnia pulex under standard and heat stress conditions.

Selenium deficiency and toxicity increase the risk of adverse developmental and reproductive outcomes; however, few multi-stressor studies have evaluated the influence of maternal age on organic selenium dose-response and additional stressors over the life course. While multi-stressor research in mammalian models is time-consuming and expensive, use of alternative models can efficiently produce screening data for prioritizing research in mammalian systems. As a well-known eco-toxicological model, Daphnia pulex, may offer advantages in screening for impacts of multi-stressor exposures. We evaluated the influence of maternal age on the effects of seleno-methionine (SeMet) for lifespan, reproduction, and heat-stress resistance in D. pulex. Our results show effects of SeMet-treatment and maternal age, where the highest SeMet-treatment had reduced lifespan and absence of reproduction, and where Daphnia from late life broods had increased resistance to heat-induced stress. Further analysis suggests an additional interactive effect between maternal age and SeMet treatment on time to first reproduction.