Successful Cessation Programs that Reduce Comorbidity May Explain Surprisingly Low Smoking Rates Among Hospitalized COVID-19 Patients

A recent, non-peer-reviewed meta-analysis suggests that smoking may reduce the risk of hospitalization with COVID-19 because the prevalence of smoking among hospitalized COVID-19 is less than that of the general population. However, there are alternative explanations for this phenomena based on (1) the failure to report, or accurately record, smoking history during emergency hospital admissions and (2) a pre-disposition to avoid smoking among COVID-19 patients with tobacco-related comorbidities (a type of “reverse” causation). For example, urine testing of hospitalized patients in Australia for cotinine showed that smokers were under-counted by 37% because incoming patients failed to inform staff about their smoking behavior. Face-to-face interviews can introduce bias into the responses to attitudinal and behavioral questions not present in the self-completion interviews typically used to measure smoking prevalence in the general population. Subjects in face-to-face interviews may be unwilling to admit socially undesirable behavior and attitudes under direct questioning. Reverse causation may also contribute to the difference between smoking prevalence in the COVID-19 and general population. Patients hospitalized with COVID-19 may be simply less prone to use tobacco than the general population. A potentially robust “reverse causation” hypothesis for reduced prevalence of smokers in the COVID-19 population is the enrichment of patients in that population with serious comorbidities that motivates them to quit smoking. We judge that this “smoking cessation” mechanism may account for a significant fraction of the reduced prevalence of smokers in the COVID-19 population. Testing this hypothesis will require a focused research program

Residual Stress Measurement of Suspension HVOF-Sprayed Alumina Coating via a Hole-Drilling Method

The nature and magnitude of residual stresses in thermal-sprayed coatings determine their lifetime and failure mechanisms. The residual stresses of suspension high-velocity oxy-fuel (SHVOF) thermal sprayed alumina (Al2O3) coating were measured with hole-drilling and x-ray diffraction. The coating is dense and consists of amorphous and two crystalline phases: alpha and gamma. The residual stresses measured by hole-drilling in the Al2O3 coating was − 162 MPa (compression) in the longitudinal direction and − 104 MPa (compression) in the transverse direction. This is due to the peening stress and the high substrate–coating CTE ratio of ~ 2.1. The nature of the residual stress through the coating is related to the microstructure build-up shown from the cross section and the fracture surfaces of the coating

Successful Cessation Programs that Reduce Comorbidity May Explain Surprisingly Low Smoking Rates Among Hospitalized COVID-19 Patients

A recent, non-peer-reviewed meta-analysis suggests that smoking may reduce the risk of hospitalization with COVID-19 because the prevalence of smoking among hospitalized COVID-19 is less than that of the general population. However, there are alternative explanations for this phenomena based on (1) the failure to report, or accurately record, smoking history during emergency hospital admissions and (2) a pre-disposition to avoid smoking among COVID-19 patients with tobacco-related comorbidities (a type of “reverse” causation). For example, urine testing of hospitalized patients in Australia for cotinine showed that smokers were under-counted by 37% because incoming patients failed to inform staff about their smoking behavior. Face-to-face interviews can introduce bias into the responses to attitudinal and behavioral questions not present in the self-completion interviews typically used to measure smoking prevalence in the general population. Subjects in face-to-face interviews may be unwilling to admit socially undesirable behavior and attitudes under direct questioning. Reverse causation may also contribute to the difference between smoking prevalence in the COVID-19 and general population. Patients hospitalized with COVID-19 may be simply less prone to use tobacco than the general population. A potentially robust “reverse causation” hypothesis for reduced prevalence of smokers in the COVID-19 population is the enrichment of patients in that population with serious comorbidities that motivates them to quit smoking. We judge that this “smoking cessation” mechanism may account for a significant fraction of the reduced prevalence of smokers in the COVID-19 population. Testing this hypothesis will require a focused research program

Pandemic (H1N1) 2009 influenza community transmission was established in one Australian state when the virus was first identified in North America

BACKGROUND In mid-June 2009 the State of Victoria in Australia appeared to have the highest notification rate of pandemic (H1N1) 2009 influenza in the world. We hypothesise that this was because community transmission of pandemic influenza was already well established in Victoria at the time testing for the novel virus commenced. In contrast, this was not true for the pandemic in other parts of Australia, including Western Australia (WA). METHODS We used data from detailed case follow-up of patients with confirmed infection in Victoria and WA to demonstrate the difference in the pandemic curve in two Australian states on opposite sides of the continent. We modelled the pandemic in both states, using a susceptible-infected-removed model with Bayesian inference accounting for imported cases. RESULTS Epidemic transmission occurred earlier in Victoria and later in WA. Only 5% of the first 100 Victorian cases were not locally acquired and three of these were brothers in one family. By contrast, 53% of the first 102 cases in WA were associated with importation from Victoria. Using plausible model input data, estimation of the effective reproductive number for the Victorian epidemic required us to invoke an earlier date for commencement of transmission to explain the observed data. This was not required in modelling the epidemic in WA. CONCLUSION Strong circumstantial evidence, supported by modelling, suggests community transmission of pandemic influenza was well established in Victoria, but not in WA, at the time testing for the novel virus commenced in Australia. The virus is likely to have entered Victoria and already become established around the time it was first identified in the US and Mexico

Menthol stereoisomers exhibit different effects on α4β2 nAChR upregulation and dopamine neuron spontaneous firing

Menthol contributes to poor cessation rates among smokers, in part because menthol enhances nicotine reward and reinforcement. Mentholated tobacco products contain (−)-menthol and (+)-menthol, in varying proportions. We examined these two menthol stereoisomers for their ability to upregulate α4β2 nAChRs and to alter dopamine neuron firing frequency using long-term, low-dose (≤ 500 nM) exposure that is pharmacologically relevant to smoking. We found that (−)-menthol upregulates α4β2 nAChRs while (+)-menthol does not. We also found that (−)-menthol decreases dopamine neuron baseline firing and dopamine neuron excitability, while (+)-menthol exhibits no effect. We then examined both stereoisomers for their ability to inhibit α4β2 nAChR function at higher concentrations (>10 µM) using the Xenopus oocyte expression system. To probe for the potential binding site of menthol, we conducted flooding simulations and site-directed mutagenesis. We found that menthol likely binds to the 9’ position on the TM2 helix. We found that menthol inhibition is dependent on the end-to-end distance of the side chain at the 9’ residue. Additionally, we have found that (−)-menthol is only modestly (∼25%) more potent than (+)-menthol at inhibiting wildtype α4β2 nAChRs and a series of L9’ mutant nAChRs. These data reveal that menthol exhibits a stereoselective effect on nAChRs and that the stereochemical effect is much greater for long-term, sub µM exposure in mice than for acute, higher level exposure. We hypothesize that of the two menthol stereoisomers, only (−)-menthol plays a role in enhancing nicotine reward through nAChRs on dopamine neurons

Patterns of Methamphetamine Use During Pregnancy: Results from the Infant Development, Environment, and Lifestyle (IDEAL) Study

The objectives of this study are to characterize methamphetamine (MA) usage patterns during pregnancy, examine whether patterns of MA use are associated with sociodemographic characteristics and prenatal care, and test the hypothesis that persistent or increasing MA use during pregnancy is associated with greater use of other illicit drugs. The sample consisted of 191 MA-using mothers who participated in a large-scale multi-site study of prenatal MA exposure. Patterns of substance use were assessed by maternal self-report via the Substance Use Inventory (SUI), which included detailed information about MA use, including frequency, quantity, and maximum use during each trimester of pregnancy. The study demostrated that on average, the prevalence of MA use decreased over the three trimesters of pregnancy (84.3% vs. 56.0% vs. 42.4%), and decreased frequency was observed among users from the first trimester to the third (3.1 vs. 2.4 vs. 1.5 days/week). Closer examination of the individual patterns revealed that 29.3% of women maintained consistently high frequency, 9.4% increased frequency, 25.7% had a stable low/moderate pattern, and 35.6% decreased their frequency of MA over the course of pregnancy. These four groups did not differ in sociodemographic characteristics; women who decreased their use of MA had significantly more prenatal visits compared to the consistently high-use group, but were the most likely to use alcohol during their pregnancy. In conclusion, this article elucidated the different patterns of MA use in this community sample. Approximately, one third of MA-using mothers could be classified as consistently high users with a profile of use with the greatest risk to themselves and potentially to their infants including high levels of MA use throughout pregnancy and fewer prenatal care visits. Overall, we found that MA use declined across pregnancy; however, a substantial proportion of users had consistently high or increasing MA use, while those who decreased their MA frequency had a higher prevalence of polydrug use. Future research will investigate the association of these patterns with neonatal outcomes

YAG thermal barrier coatings deposited by suspension and solution precursor thermal spray

Yttrium aluminium garnet (YAG) is a promising topcoat material for thermal barrier coatings due to its high temperature stability and better CMAS (calcium-magnesium-alumino-silicate) resistance. YAG topcoats were deposited by suspension and solution precursor high-velocity oxy-fuel (HVOF) thermal spray. The relationships between processing, microstructure and final properties were studied through a range of characterization techniques and thermal cycling tests. The microstructure of the as-sprayed YAG topcoat from stoichiometric solution precursor (SP-YAG) had distributed pores and inter-splat boundaries, while the as-sprayed topcoat produced from suspension (S-YAG) had vertical and branched micro cracks, pores, and inter-splat boundaries. Both as-sprayed coatings were composed of amorphous phase, hexagonal yttrium aluminium perovskite (YAP) and cubic YAG. In thermal cycling tests, 20% of SP-YAG failure was reached after the 10th cycle; whereas, S-YAG reached the failure criteria between the 60th and 70th cycle. The failure of both the SP-YAG and the S-YAG topcoats occurred due to thermal stresses during the thermal cycling

Disclosure of Maternal HIV Status to Children: To Tell or Not To Tell . . . That Is the Question

HIV-infected mothers face the challenging decision of whether to disclose their serostatus to their children. From the perspective of both mother and child, we explored the process of disclosure, providing descriptive information and examining the relationships among disclosure, demographic variables, and child adjustment. Participants were 23 mothers and one of their noninfected children (9 to 16 years of age). Sixty-one percent of mothers disclosed. Consistent with previous research, disclosure was not related to child functioning. However, children sworn to secrecy demonstrated lower social competence and more externalizing problems. Differential disclosure, which occurred in one-third of the families, was associated with higher levels of depressive and anxiety symptoms. Finally, knowing more than mothers had themselves disclosed was related to child maladjustment across multiple domains. Clinical implications and the need for future research are considered

Menthol stereoisomers exhibit different effects on α4β2 nAChR upregulation and dopamine neuron spontaneous firing

Menthol contributes to poor cessation rates among smokers, in part because menthol enhances nicotine reward and reinforcement. Mentholated tobacco products contain (−)-menthol and (+)-menthol, in varying proportions. We examined these two menthol stereoisomers for their ability to upregulate α4β2 nAChRs and to alter dopamine neuron firing frequency using long-term, low-dose (≤ 500 nM) exposure that is pharmacologically relevant to smoking. We found that (−)-menthol upregulates α4β2 nAChRs while (+)-menthol does not. We also found that (−)-menthol decreases dopamine neuron baseline firing and dopamine neuron excitability, while (+)-menthol exhibits no effect. We then examined both stereoisomers for their ability to inhibit α4β2 nAChR function at higher concentrations (>10 µM) using the Xenopus oocyte expression system. To probe for the potential binding site of menthol, we conducted flooding simulations and site-directed mutagenesis. We found that menthol likely binds to the 9’ position on the TM2 helix. We found that menthol inhibition is dependent on the end-to-end distance of the side chain at the 9’ residue. Additionally, we have found that (−)-menthol is only modestly (∼25%) more potent than (+)-menthol at inhibiting wildtype α4β2 nAChRs and a series of L9’ mutant nAChRs. These data reveal that menthol exhibits a stereoselective effect on nAChRs and that the stereochemical effect is much greater for long-term, sub µM exposure in mice than for acute, higher level exposure. We hypothesize that of the two menthol stereoisomers, only (−)-menthol plays a role in enhancing nicotine reward through nAChRs on dopamine neurons

Self-assembled titanium-based macrostructures with hierarchical (macro-, micro-, and nano) porosities : a fundamental study

This study details the novel self-assembly of sodium titanate converted Ti-based microspheres into hierarchical porous 3D constructs, with macro-, micro-, and nanoporosity, for the first time. Ti6Al4V microspheres were suspended into 5 M NaOH (60 °C/24 h) solutions, with extensive variations in microsphere:solution ratios to modify microsphere interaction and initiate self-assembly through proximity merging of titanate surface dendritic growth. The formed structures, which either produced 1) unbonded, sodium titanate-converted microspheres; 2) flat (non-macroporous) scaffolds; or 3) open, hierarchically porous scaffolds, were then assessed in terms of their formation mechanism, chemical composition, porosity, as well as the effect of post-heat treatments on compressive mechanical properties. It was found that specific microsphere:solution ratios tended to form certain structures (3 flat non-macroporous, >8 powder) due to a combination of microsphere freedom of movement, H2 gas bubble formation, and exposed surface reactivity. This promising discovery highlights the potential for lower temperature, simplistic production of 3D constructs with modifiable chemical properties due to the ion-exchange potential of titanate structures, with clear applications in a wide-range of fields, from medical materials to catalysts