Seeing is Believing: Chasing Sevoflurane Vapor Trails

PURPOSE

Sevoflurane is an inhalational general anesthetic that has been used recently to treat chronic, painful lesions, reportedly supporting analgesia and wound healing. The potential for repeated exposure to off-gassed sevoflurane vapor, especially outside the air-conditioned operating theatre environment, is of some concern.

DESIGN

This paper explores the qualitative and quantitative pathing of off-gassed sevoflurane from a topically applied liquid source.

METHODS

Using a small, unventilated test-box (total volume 0.5 m3) with infra-red imaging and gas-analysing, we investigated the spatial distribution of sevoflurane vapor following complete vaporization of a 20 mL liquid sample. Utilizing the infra-red absorption of sevoflurane, it was possible to visualize (as an apparent reduction in temperature) the streaming path of the sevoflurane vapor. Sevoflurane levels (%) in the test-box were measured using an infra-red gas analyzer.

FINDINGS

In keeping with its higher density than air, sevoflurane vapor was seen to "waterfall" from the liquid source and accumulate in the bottom of the test-box. Sevoflurane vapor concentration was minimal above the liquid source. When extrapolated to a larger (unventilated) room, we estimate that the sevoflurane concentration would be less than 10 ppm one centimetre above the liquid pool. With vacuum extraction, these levels would be even lower.

CONCLUSIONS

Due to sevoflurane's tendency to accumulate on the floor, it is concluded that topical application of liquid sevoflurane posses virtually no risk to off-gas exposure in unventilated spaces.

Sex Differences in Response-Contingent Cannabis Vapor Administration During Adolescence Mediate Enduring Effects on Behavioral Flexibility and Prefrontal Microglia Activation in Rats

Introduction: Cannabis is the most used illicit drug in the United States. With many states passing legislation to permit its recreational use, there is concern that cannabis use among adolescents could increase dramatically in the coming years. Historically, it has been difficult to model real-world cannabis use to investigate the causal relationship between cannabis use in adolescence and behavioral and neurobiological effects in adulthood. Materials and Methods: We used a response-contingent vapor administration model to investigate long-term effects of cannabis use during adolescence on the medial prefrontal cortex (mPFC) and mPFC-dependent behaviors in male and female rats. Results: Adolescent (35- to 55-day-old) female rats had significantly higher rates of responding for vaporized Δ9-tetrahydrocannabinol (THC)-dominant cannabis extract (CANTHC) compared with adolescent males. In adulthood (70-110 days old), female, but not male, CANTHC rats also took more trials to reach criterion and made more regressive errors in an automated attentional set-shifting task compared with vehicle rats, thereby indicating sex differences in behavioral flexibility impairments. Notably, sex-treatment interactions were not observed when rats of each sex were exposed to a noncontingent CANTHC vapor dosing regimen that approximated CANTHC vapor deliveries earned by females. No differences were observed in effort-based decision making in either sex. In the mPFC, female (but not male) CANTHC rats displayed more reactive microglia with no changes in myelin basic protein expression or dendritic spine density. Conclusion: Altogether, these data reveal important sex differences in rates of responding for CANTHC vapor in adolescence that may confer enduring alterations to mPFC structure and function and suggest that there may be subtle differences in the effects of response-contingent versus noncontingent cannabis exposure that should be systematically examined in future studies.

The Impact of Hydrogen Peroxide (H2O2) Fumigation on Bacterial Levels in Dental Office Environments: A Randomized Clinical Trial Investigation

BACKGROUND

Fumigation with hydrogen peroxide has proven to be a highly effective approach to maintaining biological safety within dental offices. The main purpose of this research was to investigate the efficacy of hydrogen peroxide (H2O2) fumigation in reducing bacterial levels in dental office environments.

METHODS

The study involved 30 participants diagnosed with moderate caries decay (ICDAS 3 and 4) in their mandibular molars. Sixty Petri dishes (two per patient) with Columbia Agar and 5% Sheep Blood were opened at the beginning of the caries treatment. After the completion of caries treatment and tooth restoration, 30 plates (G1 group) were closed. Following this, a 20 min fumigation procedure with 6% hydrogen peroxide biosanitizer using a compressed air device was conducted. After the fumigation, the remaining plates were closed (G2 group). The total number of bacteria CFUs (colony-forming units) in the dental office air was determined using the Koch sedimentation method.

RESULTS

The total bacterial colony (TBC) level, measured in cfu/m3, demonstrated a significant decrease in the number of bacteria following room environment fumigation (163.1 ± 145.7; G2 group) compared to non-fumigated samples (817.2 ± 208.2; G1 group) (p < 0.001). The predominant bacteria observed in the microbiological plates before fumigation were Micrococcus and Bacillus species, found in 80% (24/30) and 60% (18/30) of the plates, respectively. Application of H2O2 room fumigation resulted in a significant reduction in bacterial numbers: 79.2% (5/30) for Micrococcus species (p < 0.001), 83.3% (3/30) for Bacillus species (p < 0.001), and 100% (0/30) for Staphylococcus arlettae (p < 0.05).

CONCLUSION

Fumigation with 6% H2O2 is an effective method for reducing bacterial counts in a dental office environment.

A combinatorial approach of Monarda citriodora essential oil (MEO) and linalool vapors to control fruit rot of Citrus limon caused by a new pathogen, Aspergillus foetidus, and its underlying mode of action

AIMS

Citrus limon (lemon) is a widely cultivated citrus fruit. Significant postharvest losses due to fungi plague its production. Environmental and human health hazards have made the application of synthetic fungicides unsuitable. Despite the previous reports of antifungal activities of essential oil (EO) vapors, their synergistic combinations are understudied. Synergistic vapor combinations are advantageous due to less concentration of active components. This study aimed to isolate and identify postharvest fungal pathogens lemon and to evaluate the antifungal effects of synergistic Monarda citriodora EO (MEO)-constituent vapor combinations in vivo and in vitro.

METHODS AND RESULTS

Postharvest fungal pathogens of lemon (C. limon) were isolated from various infected samples. The most pathogenic isolate was identified through morphology and its ITS-based rRNA gene sequencing as Aspergillus foetidus (O4). This is the first report of A. foetidus as a postharvest pathogen of lemon. The minimum fungicidal concentrations (MFCs) of MEO vapors treatment against O4 were 1346.15 µL/L air. For carvacrol, hexanal, and linalool, MFC was same (96.16 µL/L air). Checkerboard assays demonstrated that 1/4 MFC of MEO (336.54 µL/L air) and 1/4 MFC of linalool (24.04 µL/L air) (M + L) were synergistic against O4. M + L vapors reduced the O4 growth on lemons during storage by 64% ± 1.50% and preserved their quality (low weight loss %, unchanged pH, increased ascorbic acid content). Propidium iodide staining, ergosterol content analysis, calcofluor white staining and chitin content analysis revealed the integrity loss of the O4 plasma membrane and cell wall. 2',7'-Dichlorofluorescin diacetate staining revealed accumulation of intracellular reactive oxygen species (ROS), and scanning electron microscopy (SEM) analysis exposed the M + L treated mycelia with malformations.

CONCLUSIONS

M + L vapors offer protection for lemons from A. foetidus and preserve their quality during storage.

Water/Vapor Assisted Fabrication of Large-Area Superprotonic Conductive Covalent Organic Framework Membranes

Fabrication of large-area ionic covalent organic framework membranes (iCOMs) remains a grand challenge. Herein, the authors report the liquid water and water vapor-assisted fabrication of large-area superprotonic conductive iCOMs. A mixed monomer solution containing 1,3,5-triformylphloroglucinol (TFP) in 1,4-dioxane and p-diaminobenzenesulfonic acid (DABA) in water is first polymerized to obtain a pristine membrane which subsequently underwent crystallization process in mixed vapors containing water vapor. During the polymerization stage, water played a role of a diluting agent, weakening the Coulombic repulsion between sulfonic acid groups. During the crystallization stage, water vapor played a role of a structure-directing agent to facilitate the formation of highly crystalline, large-area iCOMs. The resulting membranes achieved a proton conductivity value of 0.76 S cm-1 at 90 °C under 100% relative humidity, which is among the highest ever reported. Using liquid water and water vapor as versatile additives open a novel avenue to the fabrication of large-area membranes from covalent organic frameworks and other kinds of crystalline organic framework materials.

Antibacterial Activity of Hexanol Vapor In Vitro and on the Surface of Vegetables

Hexanol is a volatile alcohol and a major component of plant essential oils (EOs). However, the antibacterial activity of hexanol vapor has not been well studied. This study aimed to evaluate the antibacterial activity of hexanol. In this study, seven food-related bacteria were exposed to 1-, 2- or 3-hexanol vapor on agar media to evaluate their growth. Additionally, the total viable counts in three vegetables when exposed to 1-hexanol vapor were measured. The results showed that 1-hexanol exhibited antibacterial effects against Gram-negative bacteria but did not affect Gram-positive bacteria. However, compounds 2- and 3-hexanol did not show antimicrobial activity against any bacteria. For the vegetables, exposure to 1-hexanol vapor decreased the total viable bacterial counts in cabbage and carrot and inhibited bacterial growth in eggplants. In cabbage, 1-hexanol vapor at concentrations over 50 ppm decreased the total viable count within 72 h, and 25 ppm of vapor showed bacteriostatic activity for 168 h. However, 1-hexanol vapor also caused discoloration in cabbage. In summary, 1-hexanol has the potential to act as an antibacterial agent, but further studies are required for practical use. Moreover, the study results may help determine the antimicrobial activity of various EOs in the future.

Improvement in the Thermal Conductivity of Silver Epoxy Adhesive by Treating with Water Vapor

With the miniaturization of electronic devices, electronic packaging has become increasingly precise and complex, which presents a significant challenge in terms of heat dissipation. Electrically conductive adhesives (ECAs), particularly silver epoxy adhesives, have emerged as a new type of electronic packaging material, thanks to their high conductivity and stable contact resistance. However, while there has been extensive research on silver epoxy adhesives, little attention has been paid to improving their thermal conductivity, which is a critical requirement in the ECA industry. In this paper, we propose a straightforward method for treating silver epoxy adhesive with water vapor, resulting in a remarkable improvement in thermal conductivity to 9.1 W/(m·K), three times higher than the sample cured using traditional methods (2.7 W/(m·K)). Through research and analysis, the study demonstrates that the introduction of H₂O into the gaps and holes of the silver epoxy adhesive increases the path of electron conduction, thereby improving thermal conductivity. Furthermore, this method has the potential to significantly improve the performance of packaging materials and meet the needs of high-performance ECAs.

Sex Differences in the Impact of Electronic Nicotine Vapor on Corticotropin-Releasing Factor Receptor 1 Neurons in the Mouse Ventral Tegmental Area

Nicotine engages dopamine neurons in the ventral tegmental area (VTA) to encode reward and drive the development of nicotine addiction, however how nicotine alters a stress associated VTA population remains unclear. Here, we used male and female CRF1-GFP mice and nicotine vapor exposure to examine the effects of nicotine in VTA corticotropin-releasing factor receptor 1 (CRF1) neurons. We use immunohistochemistry and electrophysiology to examine neuronal activity, excitability, and inhibitory signaling. We found that VTA CRF1 neurons are mainly dopaminergic and project to the nucleus accumbens (NAc; VTA-NAcCRF1 neurons). VTA-NAcCRF1 neurons show greater phasic inhibition in naive females and greater focal nicotine-induced increases in firing in naive males. Following acute nicotine vapor exposure, phasic inhibition was not altered, but focal nicotine-induced tonic inhibition was enhanced in females and diminished in males. Acute nicotine vapor exposure did not affect firing in VTA-NAcCRF1 neurons, but females showed lower baseline firing and higher focal nicotine-induced firing. Activity (cFos) was increased in the CRF1 dopaminergic VTA population in both sexes, but with greater increases in females. Following chronic nicotine vapor exposure, both sexes displayed reduced basal phasic inhibition and the sex difference in tonic inhibition following acute vapor exposure was no longer observed. Additionally, activity of the CRF1 dopaminergic VTA population was no longer elevated in either sex. These findings reveal sex-dependent and exposure-dependent changes in mesolimbic VTA-NAc CRF1 neuronal activity, inhibitory signaling, and nicotine sensitivity following nicotine vapor exposure. These changes potentially contribute to nicotine-dependent behaviors and the intersection between stress, anxiety, and addiction.SIGNIFICANCE STATEMENT Nicotine is known to engage reward systems in the brain historically centering the neurotransmitter dopamine however, how nicotine impacts other neurons in the reward pathway is less clear. The current study investigates the impact of acute and chronic electronic nicotine vapor exposure in a genetically-defined cell population containing the stress receptor corticotropin-releasing factor 1 (CRF1) that is located in the reward circuitry. This study employs functional measures of neuronal activity and identifies important sex differences in nicotine's effects across time and exposure.

Nano Edible Coatings and Films Combined with Zinc Oxide and Pomegranate Peel Active Phenol Compounds Has Been to Extend the Shelf Life of Minimally Processed Pomegranates

Edible coating and film from chitosan and incorporating it with the action of ZnONPs on active phenol compounds from extracts of pomegranate peel (PPE) The physical and chemical properties of edible films composed of zinc oxide ZnONPs and active phenol compounds extracted from pomegranate peel (PPE) were investigated. Adding ZnONPs with active phenol compounds from extracted pomegranate peel(PPE) to chitosan films can provide safe edible films, decrease microbial growth and consequently prolong the shelf life of pomegranates, as well as improve the physiochemical stability of the pomegranate. The substances used in this experiment were film with a (A) extract of pomegranate peels (PPE), 5% (0.1%), (B)ZnONPs 1% (0.02%), (C) ZnONPs 2% (0.04%), (D) ZnONPs 3% (0.06%), (E) ZnONPs 1%/PPE1% (0.02%), (F) ZnONPs 2%/PPE2% (0.04%), (G) ZnONPs 3%/PPE3% (0.06%) wt% of chitosan on quality attributes and prolonging the shelf life of pomegranates were stored in plastic containers at 2 °C and 90-95% relative humidity for 20 days. The treatments of (G) ZnONPs 3%/PPE3% (0.06%) loaded on chitosan as well as chitosan and (D) ZnONPs 3% (0.06%) reduced the weight loss, had excellent microbial count until 20 days of storage, and recorded the lowest microbial count and mould & yeast colonies. Other chemical properties, such as total soluble solids content, acidity, anthocyanin content, firmness, and ascorbic acid, were investigated. Results indicated that ZnONPs 3%/PPE3% (0.06%) loaded on chitosan or ZnONPs 3% (0.06%) are the best treatments for preserving pomegranate arils. It was found that the best measurements were that the film-forming nan emulsion solutions decreased by E% 110 nm and B% 134 nm. Nano followed treatment, F% 188.7 nm, compared to nano edible films, which were A 0% 1312 nm.

Sex differences in adolescent cannabis vapor self-administration mediate enduring effects on behavioral flexibility and prefrontal microglia activation in rats

Cannabis is the most used illicit drug in the United States. With many states passing legislation to permit its recreational use, there is concern that cannabis use among adolescents could increase dramatically in the coming years. Historically, it has been difficult to model real-world cannabis use to investigate the causal relationship between cannabis use in adolescence and behavioral and neurobiological effects in adulthood. To this end, we used a novel volitional vapor administration model to investigate long-term effects of cannabis use during adolescence on the medial prefrontal cortex (mPFC) and mPFC-dependent behaviors in male and female rats. Adolescent (35-55 day old) female rats had significantly higher rates of responding for vaporized Δ9-tetrahydrocannabinol (THC)-dominant cannabis extract (CANTHC) compared to adolescent males. In adulthood (70-110 day old), female, but not male, CANTHC rats also took more trials to reach criterion and made more regressive errors in an automated attentional set-shifting task compared to vehicle rats. Similar set-shifting deficits were observed in males when they were exposed to a non-contingent CANTHC vapor dosing regimen that approximated CANTHC self-administration rates in females. No differences were observed in effort-based decision making in either sex. In the mPFC, female (but not male) CANTHC rats displayed more reactive microglia with no significant changes in myelin basic protein expression or dendritic spine density. Together, these data reveal important sex differences in rates of cannabis vapor self-administration in adolescence that confer enduring alterations to mPFC structure and function. Importantly, female-specific deficits in behavioral flexibility appear to be driven by elevated rates of CANTHC self-administration as opposed to a sex difference in the effects of CANTHC vapor per se.

Fundamentals and Applications of Polymer Brushes in Air

For several decades, high-density, end-tethered polymers, forming so-called polymer brushes, have inspired scientists to understand their properties and to translate them to applications. While earlier research focused on polymer brushes in liquids, it was recently recognized that these brushes can find application in air as well. In this review, we report on recent progress in unraveling fundamental concepts of brushes in air, such as their vapor-swelling and solvent partitioning. Moreover, we provide an overview of the plethora of applications in air (e.g., in sensing, separations or smart adhesives) where brushes can be key components. To conclude, we provide an outlook by identifying open questions and issues that, when solved, will pave the way for the large scale application of brushes in air.

Kinetics of Sorption in Hygroscopic Hydrogels

Hygroscopic hydrogels hold significant promise for high-performance atmospheric water harvesting, passive cooling, and thermal management. However, a mechanistic understanding of the sorption kinetics of hygroscopic hydrogels remains elusive, impeding an optimized design and broad adoption. Here, we develop a generalized two-concentration model (TCM) to describe the sorption kinetics of hygroscopic hydrogels, where vapor transport in hydrogel micropores and liquid transport in polymer nanopores are coupled through the sorption at the interface. We show that the liquid transport due to the chemical potential gradient in the hydrogel plays an important role in the fast kinetics. The high water uptake is attributed to the expansion of hydrogel during liquid transport. Moreover, we identify key design parameters governing the kinetics, including the initial porosity, hydrogel thickness, and shear modulus. This work provides a generic framework of sorption kinetics, which bridges the knowledge gap between the fundamental transport and practical design of hygroscopic hydrogels.

Effect of Humid Air Exposed to IR Radiation on Enzyme Activity

Water vapor absorbs well in the infra-red region of the electromagnetic spectrum. Absorption of radiant energy by water or water droplets leads to formation of exclusion zone water that possesses peculiar physico-chemical properties. In the course of this study, normally functioning and damaged alkaline phosphatase, horseradish peroxidase and catalase were treated with humid air irradiated with infrared light with a wavelength in the range of 1270 nm and referred to as coherent humidity (CoHu). One-minute long treatment with CoHu helped to partially protect enzymes from heat inactivation, mixed function oxidation, and loss of activity due to partial unfolding. Authors suggest that a possible mechanism underlying the observed effects involves altering the physicochemical properties of aqueous media while treatment of the objects with CoHu where CoHu acts as an intermediary.

Liquid-dependent impedance induced by vapor condensation and percolation in nanoparticle film

A liquid-dependent impedance is observed by vapor condensation and percolation in the void space between nanoparticles. Under the Laplace pressure, vapor is effectively condensed into liquid to fill the nanoscale voids in an as-deposited nanoparticle film. Specifically, the transient impedance of the nanoparticle film in organic vapor is dependent on the vapor pressure and the conductivity of the condensed liquid. The response follows a power law that can be explained by the classical percolation theory. The condensed vapor gradually percolates into the void space among nanoparticles. A schematic is proposed to describe the vapor condensation and percolation dynamics among the nanoparticles. These findings offer insights into the behavior of vapor adsorbates in nanomaterial assemblies that contain void space.

Maternal-fetal transmission of delta-9-tetrahydrocannabinol (THC) and its metabolites following inhalation and injection exposure during pregnancy in rats

Cannabis use during pregnancy has increased over the past few decades, with recent data indicating that, in youth and young adults especially, up to 22% of people report using cannabis during pregnancy. Animal models provide the ability to study prenatal cannabis exposure (PCE) with control over timing and dosage; however, these studies utilize both injection and inhalation approaches. While it is known that Δ9-tetrahydrocannabinol (THC; primary psychoactive component of cannabis) can cross the placenta, examination of the transmission and concentration of THC and its metabolites from maternal blood into the placenta and fetal brain remains relatively unknown, and the influence of route of administration has never been examined. Pregnant female rats were exposed to either vaporized THC-dominant cannabis extract for pulmonary consumption or subcutaneous injection of THC repeatedly during the gestational period. Maternal blood, placenta, and fetal brains were collected following the final administration of THC for analysis of THC and its metabolites, as well as endocannabinoid concentrations, through mass spectrometry. Both routes of administration resulted in the transmission of THC and its metabolites in placenta and fetal brain. Repeated exposure to inhaled THC vapor resulted in fetal brain THC concentrations that were about 30% of those seen in maternal blood, whereas repeated injections resulted in roughly equivalent concentrations of THC in maternal blood and fetal brain. Neither inhalation nor injection of THC during pregnancy altered fetal brain endocannabinoid concentrations. Our data provide the first characterization of maternal-fetal transmission of THC and its metabolites following both vaporized delivery and injection routes of administration. These data are important to establish the maternal-fetal transmission in preclinical injection and inhalation models of PCE and may provide insight into predicting fetal exposure in human studies.

Rodent models for nicotine withdrawal

BACKGROUND

Animal models are critical to improve our understanding of the neuronal mechanisms underlying nicotine withdrawal. Nicotine dependence in rodents can be established by repeated nicotine injections, chronic nicotine infusion via osmotic minipumps, oral nicotine intake, tobacco smoke exposure, nicotine vapor exposure, and e-cigarette aerosol exposure. The time course of nicotine withdrawal symptoms associated with these methods has not been reviewed in the literature.

AIM

The goal of this review is to discuss nicotine withdrawal symptoms associated with the cessation of nicotine, tobacco smoke, nicotine vapor, and e-cigarette aerosol exposure in rats and mice. Furthermore, age and sex differences in nicotine withdrawal symptoms are reviewed.

RESULTS

Cessation of nicotine, tobacco smoke, nicotine vapor, and e-cigarette aerosol exposure leads to nicotine withdrawal symptoms such as somatic withdrawal signs, changes in locomotor activity, anxiety- and depressive-like behavior, learning and memory deficits, attention deficits, hyperalgesia, and dysphoria. These withdrawal symptoms are most pronounced within the first week after cessation of nicotine exposure. Anxiety- and depressive-like behavior, and deficits in learning and memory may persist for several months. Adolescent (4-6 weeks old) rats and mice display fewer nicotine withdrawal symptoms than adults (>8 weeks old). In adult rats and mice, females show fewer nicotine withdrawal symptoms than males. The smoking cessation drugs bupropion and varenicline reduce nicotine withdrawal symptoms in rodents.

CONCLUSION

The nicotine withdrawal symptoms that are observed in rodents are similar to those observed in humans. Tobacco smoke and e-cigarette aerosol contain chemicals and added flavors that enhance the reinforcing properties of nicotine. Therefore, more valid animal models of tobacco and e-cigarette use need to be developed by using tobacco smoke and e-cigarette aerosol exposure methods to induce dependence.

Major Constituents of Cannabis Vape Oil Liquid, Vapor and Aerosol in California Vape Oil Cartridge Samples

During the E-cigarette or Vaping product use Associated Lung Injury (EVALI) outbreak of August 2019 to February 2020, the California Department of Public Health, Food and Drug Laboratory Branch received numerous cannabis vape oil cartridge investigation samples from throughout the state. Many of these products were directly linked to patients; others were collected as part of investigations. We determined the major ingredients and additives in twelve unused cannabis vape oil cartridge samples obtained before (n = 2) and during the EVALI outbreak (n = 10) in California from September 2018 to December 2019. We tested for major constituents in vape oil liquid, vape oil vapor, and vape oil aerosol phases. A nontargeted Gas Chromatography Mass Spectrometry direct injection screening method was developed for vape oils, a headspace heating module used for vape oil vapors and a solid-phase microextraction (SPME) vaping rig for aerosols generated by vaping. We have identified more than 100 terpenes and natural extracts, 19 cannabinoids, and other potential toxic additives such as Vitamin E Acetate, Polyethylene Glycols, and Medium Chain Triglycerides. We determined more terpenes and minor cannabinoids can be produced via vaporizing and aerosolizing the vape oil. Delta9-THC and potential toxic additives were found at lower levels in the vapor and aerosol than in the vape liquid.

Progressive Cellular Architecture in Microscale Gas Chromatography for Broad Chemical Analyses

Gas chromatography is widely used to identify and quantify volatile organic compounds for applications ranging from environmental monitoring to homeland security. We investigate a new architecture for microfabricated gas chromatography systems that can significantly improve the range, speed, and efficiency of such systems. By using a cellular approach, it performs a partial separation of analytes even as the sampling is being performed. The subsequent separation step is then rapidly performed within each cell. The cells, each of which contains a preconcentrator and separation column, are arranged in progression of retentiveness. While accommodating a wide range of analytes, this progressive cellular architecture (PCA) also provides a pathway to improving energy efficiency and lifetime by reducing the need for heating the separation columns. As a proof of concept, a three-cell subsystem (PCA3mv) has been built; it incorporates a number of microfabricated components, including preconcentrators, separation columns, valves, connectors, and a carrier gas filter. The preconcentrator and separation column of each cell are monolithically implemented as a single chip that has a footprint of 1.8 × 5.2 cm2. This subsystem also incorporates two manifold arrays of microfabricated valves, each of which has a footprint of 1.3 × 1.4 cm2. Operated together with a commercial flame ionization detector, the subsystem has been tested against polar and nonpolar analytes (including alkanes, alcohols, aromatics, and phosphonate esters) over a molecular weight range of 32-212 g/mol and a vapor pressure range of 0.005-231 mmHg. The separations require an average column temperature of 63-68 °C within a duration of 12 min, and provide separation resolutions >2 for any two homologues that differ by one methyl group.

Self-administration of inhaled delta-9-tetrahydrocannabinol and synthetic cannabinoids in non-human primates

Cannabis and synthetic cannabinoids are abused in spite of possible adverse health consequences. The current study investigated the reinforcing effects of an ecologically relevant mode of administration (inhalation) of delta-9-tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, and three synthetic cannabinoids detected in synthetic cannabinoid products (JWH-018, JWH-073, and HU-210) in non-human primates (NHPs). Male and female (N = 4 each) rhesus macaques were trained to inhale warm air via a metal stem to receive a candy reinforcer, an alcohol aerosol vehicle was then paired with the candy. Dose-dependent responding for inhaled aerosols of THC (2.0-16.0 μg/kg/inhalation), JWH-018 (0.2-1.6 μg/kg/inhalation), JWH-073 (2.0-8.0 μg/kg/inhalation), and HU-210 (1.0-8.0 μg/kg/inhalation) was established using a fixed-ratio five schedule of reinforcement and compared to vehicle (alcohol) self-administration. Dose-dependent responding for inhaled heroin (25.0-100.0 μg/kg/inhalation), a known reinforcer in NHPs, was also established. Responding approximated vehicle levels for many drug doses tested, but at least half of the monkeys responded for ≥ one dose of each cannabinoid and heroin above vehicle, with the exception of THC. Drug deliveries calculated as percent vehicle followed a prototypical inverted-U shaped dose-response curve for cannabinoids and heroin except for THC and JWH-018 (in males). Grouped data according to sex demonstrated that peak percent of vehicle reinforcers earned for THC was greater in males than females, whereas peak percent of vehicle reinforcers earned for JWH-018, HU-210, and heroin were greater in females than males. These findings indicate minimal reinforcing effects of CB1 receptor agonists when self-administered by NHPs via aerosol inhalation. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The biofilm formation of nontuberculous mycobacteria and its inhibition by essential oils

Background

Nontuberculous mycobacteria (NTM) form two types of biofilms: Bottom biofilm and pellicle. The spatial distribution of cells between these types of biofilms and their dispersion into the liquid medium depends on the ratio of the nutrient components of the growth medium. The inhibition of biofilm formation by NTM can be achieved through the use of lipophilic compounds, such as essential oils (EOs).

Method

The biofilm and pellicle formation of Mycobacterium smegmatis and Mycobacterium avium on four nutrient media under static conditions and in the vapors of six EOs was evaluated by conventional method. The antimycobacterial effect of EOs was also studied by the disc diffusion method.

Results

The bottom biofilm and pellicle formation of NTM largely depended on the composition and availability of nutrients. Nutrient media in which NTM form powerful bottom biofilm or pellicle or both have been determined. The growth of studied NTM strains on agar was highly sensitive to the EOs of Scots pine, Atlas cedar, bergamot, and a mixture of EO of different plants. The cultivation of bacteria in the EO vapors also resulted in total suppression of the pellicle for all studied NTM strains.

Conclusions

Our data clearly indicate that the carbon-nitrogen ratio is involved in the regulation of the spatial distribution of the biofilm. The preventing effect of EOs vapors, especially the synergistic action of mixture of EOs on the biofilm and pellicle formation by NTMs can be observed.

Water Vapor Endometrial Ablation for Heavy Menstrual Bleeding: 36-Month Follow-Up of a Prospective, Multicenter Pivotal Clinical Trial

Study Objective

To report 36-month follow-up of a pivotal trial that evaluated the safety and effectiveness of the AEGEA Water Vapor System for the treatment of heavy menstrual bleeding (HMB) secondary to Abnormal Uterine Bleeding due to Endometrial disorders or Leiomyomata (AUB-E and AUB-L).

Methods

A prospective, multicenter, single-arm clinical trial at 14 sites in the US, Canada, Mexico, and the Netherlands. Inclusion criteria included a Pictorial Blood Loss Assessment (PBLAC, Higham) score ≥150 and allowed treatment of subjects with leiomyomata classified by the International Federation of Gynecology and Obstetrics (FIGO) Types 2–6 up to 4 cm in diameter, a uterine cavity up to 12 cm in length (uterine sound), Essure^® contraceptive inserts and/or prior cesarean section. Follow-up assessments were conducted annually up to 36 months after endometrial ablation. The following outcomes were evaluated for 125/155 women: gynecological adverse events, qualitative assessment of menstrual flow, quality of life using the Menorrhagia Impact Questionnaire (MIQ), patient satisfaction, and medical or surgical reintervention for AUB.

Results

One hundred and fifty-five premenopausal women aged 30 to 50 years were enrolled from September 2014 through May 2015. Water vapor endometrial ablation was performed under varying anesthesia/sedation regimens in offices, surgical centers and operating rooms. There were 6 procedure-related adverse events that occurred between 12- and 36-month follow-up, 1 of which was deemed serious (hematometra managed successfully hysteroscopically). Seventy-two percent reported amenorrhea or light menstrual flow. The mean quality of life (MIQ) score improved from 14.7 at baseline to 6.4. Ninety-three percent reported “Satisfied” or “Very Satisfied.” Post-ablation hysterectomy for any indication was performed in 6.5% of patients, and the total rate of re-intervention for bleeding was 7.1%.

Conclusion

Outcomes 36-months after water vapor endometrial ablation for HMB are consistent with 12- and 24-month follow-up results in all subgroups evaluated. The AEGEA Water Vapor System increases the population of patients amenable to efficacious and acceptable treatment of Heavy Menstrual Bleeding (HMB) due to Abnormal Uterine Bleeding (AUB-E,-L). CinicalTrials.gov NCT01979861 registered November 8, 2013.

Antibacterial and Antifungal Activity of Propyl-Propane-Thiosulfinate and Propyl-Propane-Thiosulfonate, Two Organosulfur Compounds from Allium cepa: In Vitro Antimicrobial Effect via the Gas Phase

Propyl-propane thiosulfinate (PTS) and propyl-propane thiosulfonate (PTSO) are two volatile compounds derived from Allium cepa with a widely documented antimicrobial activity. The aim of this study was to evaluate their anti-candidiasis activity and the ability of its gaseous phase to inhibit bacterial and yeast growth in vitro. The minimum inhibitory concentration of various antifungal products (including PTS and PTSO) was determined versus 203 clinical isolates of Candida spp. through broth microdilution assay. Additionally, the antimicrobial activity through aerial diffusion of PTS and PTSO was evaluated over the growth of a collection of bacteria and yeasts cultivated in agar plates. All yeasts were susceptible to the antifungals tested, except C. glabrata and C. krusei, that showed azole resistance. PTSO (MIC₅₀ and MIC₉₀ ranged from 4 to 16 mg/L and 8 to 32 mg/L, respectively) was significantly more active against yeasts than PTS (MIC₅₀ and MIC₉₀ ranged from 16 to 64 mg/L and 32 to 64 mg/L). Values were higher than those obtained for antifungal drugs. Gaseous phases of PTS and PTSO generated growth inhibition zones whose diameters were directly related to the substances concentration and inversely related to the microbial inoculum. The quantification of PTS and PTSO levels reached in the growth media through aerial diffusion displayed a concentration gradient from the central zone to the periphery. Only P. aeruginosa ATCC 27853 showed resistance, while yeasts (C. albicans ATCC 200955 and C. krusei ATCC 6258) presented the higher susceptibility to both compounds. These results suggest that PTS and PTSO display antibacterial and anti-candidiasis activity in vitro through aerial diffusion, having potential use in human therapy.

Vaporized Cannabis Extracts Have Reinforcing Properties and Support Conditioned Drug-Seeking Behavior in Rats

Recent trends in cannabis legalization have increased the necessity to better understand the effects of cannabis use. Animal models involving traditional cannabinoid self-administration approaches have been notoriously difficult to establish and differences in the drug used and its route of administration have limited the translational value of preclinical studies. To address this challenge in the field, we have developed a novel method of cannabis self-administration using response-contingent delivery of vaporized Δ⁹-tetrahydrocannabinol-rich (CAN_THC) or cannabidiol-rich (CAN_CBD) whole-plant cannabis extracts. Male Sprague-Dawley rats were trained to nose-poke for discrete puffs of CAN_THC, CAN_CBD, or vehicle (VEH) in daily 1 h sessions. Cannabis vapor reinforcement resulted in strong discrimination between active and inactive operanda. CAN_THC maintained higher response rates under fixed ratio schedules and higher break points under progressive ratio schedules compared with CAN_CBD or VEH, and the number of vapor deliveries positively correlated with plasma THC concentrations. Moreover, metabolic phenotyping studies revealed alterations in locomotor activity, energy expenditure, and daily food intake that are consistent with effects in human cannabis users. Furthermore, both cannabis regimens produced ecologically relevant brain concentrations of THC and CBD and CAN_THC administration decreased hippocampal CB1 receptor binding. Removal of CAN_THC reinforcement (but not CAN_CBD) resulted in a robust extinction burst and an increase in cue-induced cannabis-seeking behavior relative to VEH. These data indicate that volitional exposure to THC-rich cannabis vapor has bona fide reinforcing properties and collectively support the utility of the vapor self-administration model for the preclinical assessment of volitional cannabis intake and cannabis-seeking behaviors.SIGNIFICANCE STATEMENT The evolving legal landscape concerning recreational cannabis use has increased urgency to better understand its effects on the brain and behavior. Animal models are advantageous in this respect; however, current approaches typically used forced injections of synthetic cannabinoids or isolated cannabis constituents that may not capture the complex effects of volitional cannabis consumption. We have developed a novel model of cannabis self-administration using response-contingent delivery of vaporized cannabis extracts containing high concentrations of Δ⁹ tetrahydrocannabinol (THC) or cannabidiol. Our data indicate that THC-rich cannabis vapor has reinforcing properties that support stable rates of responding and conditioned drug-seeking behavior. This approach will be valuable for interrogating effects of cannabis and delineating neural mechanisms that give rise to aberrant cannabis-seeking behavior.

[Emission Status and Standards of Volatile Organic Compounds from Chinese and Foreign Bulk Petroleum Terminals]

Chinese emission standard of air pollutants for bulk gasoline terminals (GB 20950-2007) stipulate standards for vapor emissions during gasoline storage and receiving in bulk gasoline terminals. However, the standards are not applicable to crude oil, aviation kerosene, naphtha, and other kinds of oil. We assess emission standards or directives for vapor processing equipment in terminals in the United States (US) and European Union (EU), and analyze the emission status of vapor processing equipment in three typical cities in China. We further propose revisions to GB 20950-2007. We made the following observations. ① US and EU standards include scope not only for gasoline, but also crude oil and other organic liquids. ② The emission limits of non-methane hydrocarbons defined in GB 20950-2007 are i) 0.5, 1.8, and 8.9 times those defined in Subpart XX, Subpart R, and Subpart Y in the US federal regulations, ii) 1.8 and 3.1 times those defined in Rule 462 and Rule 1142 in southern California law, and iii) 0.7 and 500 times those defined in EU and German directives, respectively. The vapor leakage limit for general areas of China is 0.5 times that defined in Subpart XX of the US standards, whereas the limits for some other specific areas of China, are 0.7 and 2.0 times those defined by Rule 462 and Rule 1142 in southern California law. ③ The numerical range of P5th-P95th of NMHC emissions from the inlet and outlet of vapor processing equipment in three typical cities of China were 115-811 g·m^-3 and 0.1-20.0 g·m^-3, respectively. The proportion of NMHC emission concentrations less than or equal to 10 g·m^-3 at the outlet of vapor processing equipment was>85%. We suggest that the scope of application of GB 20950-2007 should be extended to crude oil, gasoline (including ethanol gasoline), aviation kerosene, and naphtha. The emission concentration limit of NMHC from vapor processing equipment should be tighten from 25 g·m^-3 to 20 g·m^-3, with a emission limit of 10 g·m^-3 added for particular cases.

EXTENDED ATTENUATION OF CORTICOSTRIATAL POWER AND COHERENCE AFTER ACUTE EXPOSURE TO VAPOURIZED Δ9 TETRAHYDROCANNABINOL IN RATS

Introduction

Over 14% of Canadians use cannabis, with nearly 60% of these individuals reporting daily or weekly use. Inhalation of cannabis vapour has recently gained popularity, but the effects of this exposure on neural activity remain unknown. In this study, we assessed the impact of acute exposure to vapourized Δ9-tetrahydrocannabinol (THC) on neural circuit dynamics in rats.

Objectives

We aimed to characterize the changes in neural activity in the dorsal striatum (dStr), orbitofrontal cortex (OFC), and prefrontal cortex (PFC), after acute exposure to THC vapour.

Methods

Rats were implanted with electrode arrays targeting the dStr, OFC, and PFC. Rats were administered THC (or vehicle) using a Volcano® vapourizer and local field potential recordings were performed in a plexiglass chamber in a cross-over design with a week-long washout period.

Results

Decreased spectral power was observed within the dStr, OFC, and PFC in the gamma range (>32-100 Hz) following vapourized THC administration. Most changes in gamma were still present 7 days after THC administration. Decreased gamma coherence was also observed between the OFC-PFC and dStr-PFC region-pairs.

Conclusion

A single exposure to vapourized THC suppresses cortical and dorsal striatal gamma power and coherence, effects that appear to last at least a week. Given the role of gamma hypofunction in schizophrenia, these findings may provide mechanistic insights into the known psychotomimetic effects of THC.

Fundamental Understanding of Water-Induced Mechanisms in Li-O2 Batteries: Recent Developments and Perspectives

Modern sustainability challenges in recent years have warranted the development of new energy storage technologies. Practical realization of the lithium-O₂ battery holds great promise for revolutionizing energy storage as it holds the highest theoretical specific energy of any rechargeable battery yet discovered. However, the complete realization of Li-O₂ batteries necessitates ambient air operations, which presents quite a few challenges, as carbon dioxide (CO₂ ) and water (H₂ O) contaminants introduce unwanted byproducts from side reactions that greatly affect battery performance. Although current research has thoroughly explored the beneficial incorporation of CO₂ , much mystery remains over the inconsistent effects of H₂ O. The presence of water in both the cathode and electrolyte has been observed to alter reaction mechanisms differently, resulting in a diverse range of effects on voltage, capacity, and cyclability. Moreover, recent preliminary research with catalysts and redox mediators has attempted to utilize the presence of water to the battery's benefit. Here, the key mechanism discrepancies of water-afflicted Li-O₂ batteries are presented, concluding with a perspective on future research directions for nonaqueous Li-O₂ batteries.

Vapor toxicity of five volatile pyrethroids against Aedes aegypti, Aedes albopictus, Culex quinquefasciatus, and Anopheles quadrimaculatus (Diptera: Culicidae)

BACKGROUND

Mosquito mortality has been documented in numerous studies of spatial repellents but the concentration-dependent toxicity of spatial repellent vapors has not been documented. To address this issue, prallethrin, flumethrin, metofluthrin, transfluthrin, and meperfluthrin were selected for comparative study against Aedes albopictus (Skuse), Ae. aegypti (L.), Culex quinquefasciatus Say, and Anopheles quadrimaculatus Say. Mosquito were exposed to vapors of each chemical for 2, 4, and 24 h with mortality recorded at each time point. A second experiment involved exposing mosquitoes to vapors for 2 h, then transferring them to untreated holding containers and held for 24 h. For these mosquitoes, readings were only taken after 24 h to allow for metabolic detoxification and recovery.

RESULTS

LC₅₀ and LC₉₀ data indicated that transfluthrin and meperfluthrin had the greatest toxicity across all species, followed by metofluthrin, prallethrin, and flumethrin.

CONCLUSION

Our findings, through the direct comparison of these compounds, suggest that transfluthrin, meperfluthrin, and metofluthrin be considered for further development. The vapor toxicity for the aforementioned compounds significantly exceeds prallethrin, which is currently market available as an adulticidal active ingredient in public health pest control. © 2018 Society of Chemical Industry.

Generation of Electronic Cigarette Aerosol by a Third-Generation Machine-Vaping Device: Application to Toxicological Studies

Electronic-cigarette (e-cig) devices use heat to produce an inhalable aerosol from a liquid (e-liquid) composed mainly of humectants, nicotine, and flavoring chemicals. The aerosol produced includes fine and ultrafine particles, and potentially nicotine and aldehydes, which can be harmful to human health. E-cig users inhale these aerosols and, with the third-generation of e-cig devices, control design features (resistance and voltage) in addition to the choice of e-liquids, and the puffing profile. These are key factors that can significantly impact the toxicity of the inhaled aerosols. E-cig research, however, is challenging and complex mostly due to the absence of standardized assessments and to the numerous varieties of e-cig models and brands, as well as e-liquid flavors and solvents that are available on the market. These considerations highlight the urgent need to harmonize e-cig research protocols, starting with e-cig aerosol generation and characterization techniques. The current study focuses on this challenge by describing a detailed step-by-step e-cig aerosol generation technique with specific experimental parameters that are thought to be realistic and representative of real-life exposure scenarios. The methodology is divided into four sections: preparation, exposure, post-exposure analysis, plus cleaning and maintenance of the device. Representative results from using two types of e-liquid and various voltages are presented in terms of mass concentration, particle size distribution, chemical composition and cotinine levels in mice. These data demonstrate the versatility of the e-cig exposure system used, aside from its value for toxicological studies, as it allows for a broad range of computer-controlled exposure scenarios, including automated representative vaping topography profiles.

Simple and Efficient Chromophoric-Fluorogenic Probes for Diethylchlorophosphate Vapor

In this work, we developed two small-molecule probes for real-time and onsite detecting of diethylchlorophosphate (DCP) vapor by incorporating amine groups into Schiff base skeletons. Both probes can be easily synthesized with high yield through one-step and low-cost synthesis. They can detect DCP vapor in the chromophoric-fluorogenic dual mode, which combines both the advantages of the visualization of color sensing and the high sensitivity of the fluorescence sensing. Furthermore, its sensing is based on the "turn-on" mode which can avoid the interference arising from photobleaching or fluorescence quenching agents based on "turn-off" mode. The detection limit was quantified to be as low as 0.14 ppb.

Extensive Hand Thermal and Blast Injury From Electronic Cigarette Explosion: A Case Report

Background: As the use of electronic cigarettes rises, more reports of injuries related to device explosion are surfacing. Methods: Presented here is the case of a 35-year-old man sustaining extensive thermal and blast injuries to his hand when the device exploded while he was holding it. He required multiple surgeries involving groin flap coverage, tendon transfer, and nerve grafting to optimize his postinjury function. Results: While much of his hand function has been restored, he has continued deficits in range of motion and sensation as a result of the incident. Conclusions: With increasing numbers of such injuries, hand surgeons must be aware of the blast mechanism involved so as to avoid missing deep soft tissue injury or disruption of deep structures, as demonstrated in this case.

E-cigarettes: voltage- and concentration-dependent loss in human lung adenocarcinoma viability

E-cigarettes are used by millions of people despite the fact that the harmful effect of aerosol emitted from these products to the human organism is still not clear. In this paper, toxicity of vapor generated using different solutions and battery output voltage on A549 cells viability is presented. The obtained EC₅₀ values for commercially available propylene glycol/glycerol solution 1:1 e-liquids based on 3.2 V (0.127%), 4.0 V (0.112%) and 4.8 V (0.038%) were about 1.5-4.5 times higher than in tobacco smoke (0.0086%). Furthermore, it was shown that the increase of battery output voltage decreased A549 cell viability. In addition, commercially available extracts were more cytotoxic than laboratory made extracts. Owing to the expansiveness of e-cigarettes, it is very important to estimate their impact on public health. Our results not only confirm less cytotoxicity of e-liquid aerosol than cigarette smoke, but also demonstrate that solutions used in e-liquids and, for the first time, battery output voltage have a significant impact on cytotoxicity of e-cigarette vapor. Thus, the results of this study are very important for the current and future legal regulations on e-cigarettes.

Antimicrobial activity of selected essential oils against Streptococcus suis isolated from pigs

The inhibitory potential by contact and vapor of basil, cinnamon, clove, peppermint, oregano, rosemary, common thyme, and red thyme essential oils (EOs) against 20 strains of Streptococcus suis was determined by the disk diffusion test. The broth microdilution method was used to determine the minimal inhibitory and minimal bactericidal concentration (MIC and MBC) of the four selected oils. Furthermore, the bactericidal power (ratio MBC/MIC) was calculated. The EOs with the major potential in the disk diffusion method were red thyme, common thyme, oregano, and cinnamon (∅ mean 16.5–34.2 mm), whereas cinnamon did not show vapor activity. In the microdilution test, all the EOs showed notable antimicrobial activity (MIC₉₀ and MBC₉₀ 312.5–625 μg·ml⁻¹) and a strong bactericidal power (ratio = 1). This is the first study that selects essential oils against S. suis. New studies about the possible synergic effect of EOs with antibiotics and about toxicity and efficacy in in vivo conditions are recommended.

Tuning Transpiration by Interfacial Solar Absorber-Leaf Engineering

Plant transpiration, a process of water movement through a plant and its evaporation from aerial parts especially leaves, consumes a large component of the total continental precipitation (≈48%) and significantly influences global water distribution and climate. To date, various chemical and/or biological explorations have been made to tune the transpiration but with uncertain environmental risks. In recent years, interfacial solar steam/vapor generation is attracting a lot of attention for achieving high energy transfer efficiency. Various optical and thermal designs at the solar absorber-water interface for potential applications in water purification, seawater desalination, and power generation appear. In this work, the concept of interfacial solar vapor generation is extended to tunable plant transpiration by showing for the first time that the transpiration efficiency can also be enhanced or suppressed through engineering the solar absorber-leaf interface. By tuning the solar absorption of membrane in direct touch with green leaf, surface temperature of green leaf will change accordingly because of photothermal effect, thus the transpiration efficiency as well as temperature and relative humidity in the surrounding environment will be tuned. This tunable transpiration by interfacial absorber-leaf engineering can open an alternative avenue to regulate local atmospheric temperature, humidity, and eventually hydrologic cycle.

Whole body exposure of rats to sulfur mustard vapor

Sulfur mustard (SM) is an incapacitating chemical warfare agent used in numerous conflicts around the world and it is still a major threat for both, army troops and civilians. To evaluate its multiple targets effects in experimental setup, a model of whole body exposure (WBE) to SM vapor was established in rats and its simultaneous effects on lungs and eyes as well as on general wellbeing were examined. Rats were exposed to SM vapor. Evaluation (up to 10 weeks post-exposure) included body weight, general observation, blood counts and histological analysis. Results showed that following a latency-period of several hours, rats typical symptoms developed over a period of more than one week. The initial symptoms, characterized by swollen and erythematic nose, deteriorated into extensive rhinorrhea, eye closure, excessive lacrimation as well as rhonchi, wheezing and breathing difficulties. Alopecia and behavioral abnormality were also recorded. A weight loss of up to 40% was measured within one week with spontaneous recovery to baseline level within three weeks after exposure. Blood counts revealed leukopenia during the first three days post-exposure. Histological evaluation revealed a long lasting damage to the trachea, lungs and eyes. Thus, WBE to SM, was found to closely mimic the deleterious effects of SM on the sensitive tissues previously described in human victims during WWI and the Iran-Iraq war. The use of this animal model will enable comprehensive characterization of changes in biological processes that may lead to the development of therapeutic measures to ameliorate SM induced multi-system injuries.

Long-Term Stability of Polymer-Coated Surface Transverse Wave Sensors for the Detection of Organic Solvent Vapors

Arrays with polymer-coated acoustic sensors, such as surface acoustic wave (SAW) and surface transverse wave (STW) sensors, have successfully been applied for a variety of gas sensing applications. However, the stability of the sensors’ polymer coatings over a longer period of use has hardly been investigated. We used an array of eight STW resonator sensors coated with different polymers. This sensor array was used at semi-annual intervals for a three-year period to detect organic solvent vapors of three different chemical classes: a halogenated hydrocarbon (chloroform), an aliphatic hydrocarbon (octane), and an aromatic hydrocarbon (xylene). The sensor signals were evaluated with regard to absolute signal shifts and normalized signal shifts leading to signal patterns characteristic of the respective solvent vapors. No significant time-related changes of sensor signals or signal patterns were observed, i.e., the polymer coatings kept their performance during the course of the study. Therefore, the polymer-coated STW sensors proved to be robust devices which can be used for detecting organic solvent vapors both qualitatively and quantitatively for several years.

Nicotine Vapor Method to Induce Nicotine Dependence in Rodents

Nicotine, the main addictive component of tobacco, induces potentiation of brain stimulation reward, increases locomotor activity, and induces conditioned place preference. Nicotine cessation produces a withdrawal syndrome that can be relieved by nicotine replacement therapy. In the last decade, the market for electronic cigarettes has flourished, especially among adolescents. The nicotine vaporizer or electronic nicotine delivery system is a battery-operated device that allows the user to simulate the experience of tobacco smoking without inhaling smoke. The device is designed to be an alternative to conventional cigarettes that emits vaporized nicotine inhaled by the user. This report describes a procedure to vaporize nicotine in the air to produce blood nicotine levels in rodents that are clinically relevant to those that are observed in humans and produce dependence. We also describe how to construct the apparatus to deliver nicotine vapor in a stable, reliable, and consistent manner, as well as how to analyze air for nicotine content. © 2017 by John Wiley & Sons, Inc.

Vapor and Gas-Bubble Growth Dynamics around Laser-Irradiated, Water-Immersed Plasmonic Nanoparticles

Microbubbles produced by exposing water-immersed metallic nanoparticles to resonant light play an important role in emerging and efficient plasmonic-enhanced processes for catalytic conversion, solar energy harvesting, biomedical imaging, and cancer therapy. How do these bubbles form, and what is their gas composition? In this paper, the growth dynamics of nucleating bubbles around laser-irradiated, water-immersed Au plasmonic nanoparticles are studied to determine the exact origin of the occurrence and growth of these bubbles. The microbubbles' contact angle, footprint diameter, and radius of curvature were measured in air-equilibrated water (AEW) and degassed water (DGW) with fast imaging. Our experimental data reveals that the growth dynamics can be divided into two regimes: an initial bubble nucleation phase (regime I, < 10 ms) and, subsequently a bubble growth phase (regime II). The explosive growth in regime I is identical for AEW and DGW due to the vaporization of water. However, the slower growth in regime II is distinctly different for AEW and DGW, which is attributed to the uptake of dissolved gas expelled from the water around the hot nanoparticle. Our scaling analysis reveals that the bubble radius scales with time as R(t) ∝ t^1/6 for both AEW and DGW in the initial regime I, whereas in the later regime II it scales as R(t) ∝ t^1/3 for AEW and is constant for perfectly degassed water. These scaling relations are consistent with the experiments.

Photoluminescent Metal-Organic Frameworks for Gas Sensing

Luminescence of porous coordination polymers (PCPs) or metal-organic frameworks (MOFs) is sensitive to the type and concentration of chemical species in the surrounding environment, because these materials combine the advantages of the highly regular porous structures and various luminescence mechanisms, as well as diversified host-guest interactions. In the past few years, luminescent MOFs have attracted more and more attention for chemical sensing of gas-phase analytes, including common gases and vapors of solids/liquids. While liquid-phase and gas-phase luminescence sensing by MOFs share similar mechanisms such as host-guest electron and/or energy transfer, exiplex formation, and guest-perturbing of excited-state energy level and radiation pathways, via various types of host-guest interactions, gas-phase sensing has its unique advantages and challenges, such as easy utilization of encapsulated guest luminophores and difficulty for accurate measurement of the intensity change. This review summarizes recent progresses by using luminescent MOFs as reusable sensing materials for detection of gases and vapors of solids/liquids especially for O₂, highlighting various strategies for improving the sensitivity, selectivity, stability, and accuracy, reducing the materials cost, and developing related devices.

Do electronic cigarettes impart a lower potential disease burden than conventional tobacco cigarettes? Review on E-cigarette vapor versus tobacco smoke

OBJECTIVES/HYPOTHESIS

Development and utilization of electronic cigarettes (ECs) resulted from the search for healthier alternatives to conventional tobacco cigarettes (TCs) and the search for alternative methods for quitting TCs. This review compares the potential disease burden presented by TC smoke to that of EC vapor.

METHODS

Potential disease burden of EC vapor versus TC smoke was assessed by reviewing clinical studies that measured inhaled components. Chemicals and carcinogens produced by vapor versus smoke were compared.

RESULTS

Studies show that EC vapors contain far less carcinogenic particles than TC smoke. Whereas ECs have the ability to reach peak serum cotinine/nicotine levels comparable to that of TCs, ECs do not cause an increase in total white blood cell count; thus, ECs have the potential to lower the risk of atherosclerosis and systemic inflammation. Use of ECs has been shown to improve indoor air quality in a home exposed to TC smoke. This reduces secondhand smoke exposure, thus having the potential to decrease respiratory illness/asthma, middle-ear disease, sudden infant death syndrome, and more. However, some studies claim that propylene glycol (PG) vapor can induce respiratory irritation and increase chances for asthma. To minimize risks, EC manufacturers are replacing PG with distilled water and glycerin for vapor production.

CONCLUSION

Based on the comparison of the chemical analysis of EC and TC carcinogenic profiles and association with health-indicating parameters, ECs impart a lower potential disease burden than conventional TCs.

A dynamic system for delivering controlled bromine and chlorine vapor exposures to weanling swine skin

CONTEXT

Assessing the hazards of accidental exposure to toxic industrial chemical (TIC) vapors and evaluating therapeutic compounds or treatment regimens require the development of appropriate animal models.

OBJECTIVE

The objective of this project was to develop an exposure system for delivering controlled vapor concentrations of TICs to the skin of anesthetized weanling pigs. Injury levels targeted for study were superficial dermal (SD) and deep dermal (DD) skin lesions as defined histopathologically.

MATERIALS AND METHODS

The exposure system was capable of simultaneously delivering chlorine or bromine vapor to four, 3-cm diameter exposure cups placed over skin between the axillary and inguinal areas of the ventral abdomen. Vapor concentrations were generated by mixing saturated bromine or chlorine vapor with either dried dilution air or nitrogen.

RESULTS

Bromine exposure concentrations ranged from 6.5 × 10(-4) to 1.03 g/L, and exposure durations ranged from 1 to 45 min. A 7-min skin exposure to bromine vapors at 0.59 g/L was sufficient to produce SD injuries, while a 17-min exposure produced a DD injury. Chlorine exposure concentrations ranged from 1.0 to 2.9 g/L (saturated vapor concentration) for exposures ranging from 3 to 90 min. Saturated chlorine vapor challenges for up to 30 min did not induce significant dermal injuries, whereas saturated chlorine vapor with wetted material on the skin surface for 30-60 min induced SD injuries. DD chlorine injuries could not be induced with this system.

CONCLUSION

The vapor exposure system described in this study provides a means for safely regulating, quantifying and delivering TIC vapors to the skin of weanling swine as a model to evaluate therapeutic treatments.

Animal models of nicotine exposure: relevance to second-hand smoking, electronic cigarette use, and compulsive smoking

Much evidence indicates that individuals use tobacco primarily to experience the psychopharmacological properties of nicotine and that a large proportion of smokers eventually become dependent on nicotine. In humans, nicotine acutely produces positive reinforcing effects, including mild euphoria, whereas a nicotine abstinence syndrome with both somatic and affective components is observed after chronic nicotine exposure. Animal models of nicotine self-administration and chronic exposure to nicotine have been critical in unveiling the neurobiological substrates that mediate the acute reinforcing effects of nicotine and emergence of a withdrawal syndrome during abstinence. However, important aspects of the transition from nicotine abuse to nicotine dependence, such as the emergence of increased motivation and compulsive nicotine intake following repeated exposure to the drug, have only recently begun to be modeled in animals. Thus, the neurobiological mechanisms that are involved in these important aspects of nicotine addiction remain largely unknown. In this review, we describe the different animal models available to date and discuss recent advances in animal models of nicotine exposure and nicotine dependence. This review demonstrates that novel animal models of nicotine vapor exposure and escalation of nicotine intake provide a unique opportunity to investigate the neurobiological effects of second-hand nicotine exposure, electronic cigarette use, and the mechanisms that underlie the transition from nicotine use to compulsive nicotine intake.

The magnetic-nanofluid heat pipe with superior thermal properties through magnetic enhancement

This study developed a magnetic-nanofluid (MNF) heat pipe (MNFHP) with magnetically enhanced thermal properties. Its main characteristic was additional porous iron nozzle in the evaporator and the condenser to form a unique flowing pattern of MNF slug and vapor, and to magnetically shield the magnet attraction on MNF flowing. The results showed that an optimal thermal conductivity exists in the applied field of 200 Oe. Furthermore, the minor thermal performance of MNF at the condenser limited the thermal conductivity of the entire MNFHP, which was 1.6 times greater than that filled with water for the input power of 60 W. The feasibilities of an MNFHP with the magnetically enhanced heat transfer and the ability of vertical operation were proved for both a promising heat-dissipation device and the energy architecture integrated with an additional energy system.

PCBs in air, soil and milk in industrialized and urban areas of KwaZulu-Natal, South Africa

Information regarding polychlorinated biphenyls (PCBs) in environmental media in Africa is limited. This paper presents results of a monitoring program conducted in KwaZulu-Natal Province, South Africa designed to characterize levels, trends and sources of airborne PCBs. Particulate and vapor samples were sampled over the 2004-2005 period at three sites. The total PCB concentration averaged 128+/-47 pgm(-3), and levels were highest in winter. Tri- through hexa-congeners predominated, and the vapor fraction was predominant. Several tetra- through hexa-chlorinated congeners had levels comparable to those at urban sites in the northern hemisphere, but hepta- through deca-congeners resembled levels at background sites. PCB source areas, deduced using spatial and temporal patterns, compositional information and trajectory analyses, likely included local, regional and global sources. Soils at three rural sites showed high PCB concentrations, and milk from a local dairy showed PCB concentrations comparable to USA levels in year 2000.

Molar Heat Capacity (Cv) for Saturated and Compressed Liquid and Vapor Nitrogen from 65 to 300 K at Pressures to 35 MPa

Molar heat capacities at constant volume (Cv ,) for nitrogen have been measured with an automated adiabatic calorimeter. The temperatures ranged from 65 to 300 K, while pressures were as high as 35 MPa. Calorimetric data were obtained for a total of 276 state conditions on 14 isochores. Extensive results which were obtained in the saturated liquid region (Cv(2) and Cσ ) demonstrate the internal consistency of the Cv (ρ,T) data and also show satisfactory agreement with published heat capacity data. The overall uncertainty of the Cv values ranges from 2% in the vapor to 0.5% in the liquid.

Measurements of the Specific Heats, Cσ , and Cv of Dense Gaseous and Liquid Ethane. J Res Natl Bur Stand A Phys Chem 1976;80A:739-759. [PMID: 32196297 PMCID: PMC5312758 DOI: 10.6028/jres.080a.069]

The specific heats of saturated liquid ethane, Cσ , have been measured at 106 temperatures in the temperature range 93 to 301 K. The specific heats at constant volume, Cv have been measured at 19 densities ranging from 0.2 to 3.1 times the critical density, at temperatures between 91 and 330 K, with pressures to 33 MPa, at 200 PVT states in all. The uncertainty of most of the measurements is estimated to be less than 2.0 percent. As the critical point is approached the uncertainty rises to about 5.0 percent. The measurements were performed to provide input data for accurate calculations of the thermodynamic properties for ethane. They are believed to be the most comprehensive specific heat measurements available for the liquid and vapor states of ethane.