Mid-infrared Doppler-free saturation absorption spectroscopy of the Q branch of CHν= 1 band using a rapid-scanning continuous-wave optical parametric oscillator.

We have developed a mid-infrared Doppler-free saturation absorption spectroscopy apparatus that employs a commercial continuous-wave optical parametric oscillator (CW OPO), complemented by a home-built automation and wavelength scanning system. Here, we report a comprehensive spectral scan of the Q branch transitions of the ν= 1 band of methane (CH) with an average linewidth (FWHM) of 4.5 MHz.

Where are Canada's PAs in 2023?

The physician assistant/associate (PA) role in Canada is slowly expanding from two provinces and 301 PAs in 2012 to five provinces with 959 PAs and 119 clinical assistants in 2022. This article reviews Canadian PA education, healthcare challenges, and future growth, providing a brief look at where in 2023 the 1,215 members of the Canadian Association of Physician Assistants are found, and some anticipated directions.

Calculated and Empirical Values of Vibronic Transition Dipole Moments of Reactive Chemical Intermediates for Determination of Concentrations.

Absorption spectroscopy has long been known as a technique for making molecular concentration measurements and has received enhanced visibility in recent years with the advent of new techniques, like cavity ring-down spectroscopy, that have increased its sensitivity. To apply the method, it is necessary to have a known molecular absorption cross section for the species of interest, which typically is obtained by measurements of a standard sample of known concentration. However, this method fails if the species is highly reactive, and indirect means for attaining the cross section must be employed.

Nicotine pharmacokinetics of electronic cigarettes: A pooled data analysis from the literature.

Several regulatory initiatives around the world restrict the amount of nicotine permitted in electronic cigarette liquids in an attempt to reproduce the nicotine delivery of combusted tobacco products, such as cigarettes, and or reduce the risk of consumers absorbing too much nicotine into their body at one time. Such an approach, however, assumes that (i) there is a strong correlation between the levels of nicotine in electronic cigarette liquids and nicotine intake into the body and (ii) that this correlation holds true across the various different types of electronic cigarette devices currently available on the market. In order to test these hypotheses, this study examines the available scientific literature on nicotine intake from electronic cigarettes, as measured by levels in the blood.

Nanodomain Formation in Planar Supported Lipid Bilayers Composed of Fluid and Polymerized Dienoyl Lipids.

Polymerization of synthetic phospholipid monomers has been widely used to enhance the stability of lipid membranes in applications such as membrane-based biosensing, where the inherent instability of fluid-phase lipid bilayers can be problematic. However, lipid polymerization typically decreases membrane fluidity, which may be required to maintain the activity of reconstituted integral proteins and peptides. Prior work has shown that a bilayer composed of binary mixtures of poly(lipid) and fluid lipid exhibits enhanced stability and supports the function of incorporated biomolecules.

Photopolymerization of Dienoyl Lipids Creates Planar Supported Poly(lipid) Membranes with Retained Fluidity.

Polymerization of substrate-supported bilayers composed of dienoylphosphatidylcholine (PC) lipids is known to greatly enhance their chemical and mechanical stability; however, the effects of polymerization on membrane fluidity have not been investigated. Here planar supported lipid bilayers (PSLBs) composed of dienoyl PCs on glass substrates were examined to assess the degree to which UV-initiated polymerization affects lateral lipid mobility. Fluorescence recovery after photobleaching (FRAP) was used to measure the diffusion coefficients (D) and mobile fractions of rhodamine-DOPE in unpolymerized and polymerized PSLBs composed of bis-sorbyl phosphatidylcholine (bis-SorbPC), mono-sorbyl-phosphatidylcholine (mono-SorbPC), bis-dienoyl-phosphatidylcholine (bis-DenPC), and mono-dienoyl phosphatidylcholine (mono-DenPC).

Label-free detection and identification of protein ligands captured by receptors in a polymerized planar lipid bilayer using MALDI-TOF MS.

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) coupled with affinity capture is a well-established method to extract biological analytes from complex samples followed by label-free detection and identification. Many bioanalytes of interest bind to membrane-associated receptors; however, the matrices and high-vacuum conditions inherent to MALDI-TOF MS make it largely incompatible with the use of artificial lipid membranes with incorporated receptors as platforms for detection of captured proteins and peptides. Here we show that cross-linking polymerization of a planar supported lipid bilayer (PSLB) provides the stability needed for MALDI-TOF MS analysis of proteins captured by receptors embedded in the membrane.

Highly stabilized, polymer-lipid membranes prepared on silica microparticles as stationary phases for capillary chromatography.

The ability to rapidly screen complex libraries of pharmacological modulators is paramount to modern drug discovery efforts. This task is particularly challenging for agents that interact with lipid bilayers or membrane proteins due to the limited chemical, physical, and temporal stability of conventional lipid-based chromatographic stationary phases. Here, we describe the preparation and characterization of a novel stationary phase material composed of highly stable, polymeric-phospholipid bilayers self-assembled onto silica microparticles.

Stabilized porous liposomes with encapsulated Gd-labeled dextran as a highly efficient MRI contrast agent.

A highly efficient contrast agent for magnetic resonance imaging was developed by encapsulating gadolinium within a stabilized porous liposome. The highly porous membrane leads to a high relaxivity of the encapsulated Gd. The stability of the liposome was improved by forming a polymer network within the bilayer membrane.

Where the Canadian physician assistants are in 2012.

Canada's physician assistant (PA) profession remains relatively unknown to the majority of Canadians, and the distribution of the approximately 300 Canadian PAs is uncertain. This report presents March 2012 findings from the 2011 Canadian PA survey, including the number of PAs employed and where they work.

The results of the first Canadian national physician assistant survey.

The first Canadian physician assistant (PA) survey was done in 2010 and used to establish baseline information on Canadian PAs' educational background, practices, role, responsibility, and satisfaction with their careers.

Synthesis of a Diverse Library of N,N-Dimethylamino Containing Monomers Appropriate as Lipid Head Groups.

We report on the synthesis of a diverse library of N,N-dimethylamino containing monomers. Subjecting these monomers to Chabrier reaction conditions would yield lipids with polymerizable head groups. This library of lipid head groups is equipped with a variety of arm lengths containing reduction-oxidation polymerizable groups at the terminus.

Physician assistants in Canada: update on health policy initiatives.

Objective: To analyze the health policies related to physician assistants (PAs) and to understand the factors influencing this medical work force movement.

Quality Of Evidence: This work combines a review of the literature and qualitative information, and it serves as a historical bookmark. The approach was selected when attempts to obtain reports or literature using customary electronic bibliography (PubMed, CINAHL, Google Scholar, EBSCO, and MEDLINE) searches in English and French, from 1970 through 2010, identified only 14 documents (including gray literature) of relevance.

Polymerized planar suspended lipid bilayers for single ion channel recordings: comparison of several dienoyl lipids.

The stabilization of suspended planar lipid membranes, or black lipid membranes (BLMs), through polymerization of mono- and bis-functionalized dienoyl lipids was investigated. Electrical properties, including capacitance, conductance, and dielectric breakdown voltage, were determined for BLMs composed of mono-DenPC, bis-DenPC, mono-SorbPC, and bis-SorbPC both prior to and following photopolymerization, with diphytanoyl phosphocholine (DPhPC) serving as a control. Poly(lipid) BLMs exhibited significantly longer lifetimes and increased the stability of air-water transfers.

Fractional polymerization of a suspended planar bilayer creates a fluid, highly stable membrane for ion channel recordings.

Suspended planar lipid membranes (or black lipid membranes (BLMs)) are widely used for studying reconstituted ion channels, although they lack the chemical and mechanical stability needed for incorporation into high-throughput biosensors and biochips. Lipid polymerization enhances BLM stability but is incompatible with ion channel function when membrane fluidity is required. Here, we demonstrate the preparation of a highly stable BLM that retains significant fluidity by using a mixture of polymerizable and nonpolymerizable phospholipids.

Differential effects of acute and chronic nicotine on Elk-1 in rat hippocampus.

Transcriptional regulation is central to the long-term effects of drugs of abuse. Activation of the extracellular signal-regulated kinase (ERK1/2) pathway underlies plasticity changes that accompany drug use. One target of ERK1/2 activation is the Ets-like transcription factor Elk-1.

Nicotinic receptors modulate transmitter cross talk in the CNS: nicotinic modulation of transmitters.

Neuronal nicotinic acetylcholine receptors (nAChRs) in the CNS appear to exert a predominantly modulatory influence on brain mechanisms, despite being fast-acting ligand-gated ion channels. Many nAChRs have an extrasynaptic location on somatodendritic regions or presynaptic terminals. They influence local excitability by depolarization and can initiate short- and long-term changes by interfacing with Ca2+ signaling pathways (Dajas- Bailador and Wonnacott, 2004).

Alpha7 nicotinic acetylcholine receptor expression in Alzheimer's disease: receptor densities in brain regions of the APP(SWE) mouse model and in human peripheral blood lymphocytes.

The brains of people with Alzheimer's disease (AD) display several characteristic pathological features, including deposits (plaques) of beta-amyloid 1-42 (Abeta1-42), intraneuronal accumulations (tangles) of hyperphosphorylated tau, degeneration of the basal forebrain cholinergic pathway, and gliosis. Abeta1-42 plaques develop in specific brain regions, including hippocampus and cortex, as well as in the vasculature. Abeta1-42 might promote neurodegeneration through the induction of free radicals and disruption of Ca2+ homeostasis, giving rise to the symptoms of AD.

Presynaptic alpha7 and non-alpha7 nicotinic acetylcholine receptors modulate [3H]d-aspartate release from rat frontal cortex in vitro.

The presynaptic nicotinic modulation of glutamatergic transmission in the CNS has been associated with activation of the alpha7 subtype of nicotinic acetylcholine receptor (nAChR) in sub-cortical regions, whereas in the frontal cortex, non-alpha7 nAChRs have been implicated. The aim of this investigation was to directly characterise nAChR-evoked release of excitatory amino acids from rat frontal cortex, by monitoring the release of [3H]D-aspartate from superfused synaptosomes or minces. Co-administration of a nAChR agonist with a depolarising stimulus enhanced [3H]D-aspartate release above the effect of depolarising agent alone.

Synthesis of 1,10-dimethylbicyclo[8.8.8]hexacosane and 1,10-dihydroxybicyclo[8.8.8]hexacosane.

[structure: see text] 1,10-Dimethylbicyclo[8.8.8]hexacosane (1) and 1,10-dihydroxybicyclo[8.

Why doesn't nicotinic ACh receptor immunoreactivity knock out?

Immunochemical analyses of protein expression and localization rely on the specificity of primary immunoreagents. A recent report, using transgenic mice, casts doubt on the specificity of three antibodies commonly used to immunolocalize alpha7 nicotinic ACh receptors. These data highlight the conundrum facing histologists--how 'real' is the labelling they see?

Precise localization of alpha7 nicotinic acetylcholine receptors on glutamatergic axon terminals in the rat ventral tegmental area.

Alpha7 neuronal nicotinic acetylcholine receptors (nAChRs) constitute one of the predominant nAChR subtypes in the mammalian brain. Within the ventral tegmental area (VTA), nicotine application, paired with postsynaptic stimulation, contributes to a form of long-term potentiation, an effect attributed to presynaptic alpha7 nAChRs on glutamatergic afferents (Mansvelder and McGehee, 2000). The aim of this study was to examine the precise subcellular distribution of alpha7 nAChRs in the adult rat VTA to establish whether these receptors are indeed present on glutamatergic axon terminals and to determine their relationship with cholinergic afferents.

Alpha bungarotoxin-1.4 nm gold: a novel conjugate for visualising the precise subcellular distribution of alpha 7* nicotinic acetylcholine receptors.

Alpha 7 subunit-containing nicotinic acetylcholine receptors (alpha7* nAChR) are involved in a variety of functions in the mammalian brain, including modulating neurotransmitter release and synaptic plasticity. Identifying the precise cellular distribution of alpha7* nAChRs with respect to the local neurochemical environment is crucial to understanding these biological roles. Current strategies for localising alpha7* nAChRs at the subcellular level have limitations.