Thermal Extraction of Polycyclic Aromatic Hydrocarbons from Atmospheric 2.5 µm Particulate Matter Collected on a Filter Paper Using a High-Temperature Headspace Method.

Recently, owing to the performance improvement of the headspace (HS)-sampling devices and its consumables, HS vial samples can be analyzed at temperatures up to 300°C. Some studies have attempted to analyze polycyclic aromatic hydrocarbons (PAHs) in atmospheric 2.5 µm particulate matter (PM 2.5) collected on a filter paper by gas chromatography/mass spectrometry (GC/MS) coupled with thermal desorption device. However, no studies have reported the use of an HS-sampling device to quantify PAHs in PM 2.5 filter paper. In this study, we found that the quantification of PAH analysis using HS-GC/MS can be improved by the following steps, so that the accuracy becomes almost the same as that of a solvent-extraction method: 1) replacement of the air in the HS vial with nitrogen, 2) limiting the solvent to toluene, 3) using the hydrolyzed polyimide-covered septum, and 4) optimization of the heating temperature and heating time of the HS vial. As a result, we succeeded in protecting PAHs in an HS vial at a high temperature and in creating an analysis method with a high recovery rate and high repeatability; the limit of quantitation of each PAH in this method was 5.4 pg m-3 in the case of a volume of 10080 m3 of air being collected on the filter paper.

Thermal desorption gas chromatography-mass spectrometric analysis of polycyclic aromatic hydrocarbons in atmospheric fine particulate matter.

Thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) is used to analyze polycyclic aromatic hydrocarbons (PAHs) in atmospheric fine particulate matter. However, despite the high sensitivity of TD-GC-MS, the recovery rate of PAHs is greatly influenced by active sites in the equipment. PAHs are decomposed or adsorbed at active sites, decreasing quantitative accuracy. Also, the thermal extraction of PAHs is easily affected by the matrix in PM2.5 samples, decreasing the thermal extraction efficiency. Herein, the analytical sensitivities of PAHs were improved by adding analyte protectant (AP) and thermal desorption aid (TDA) as an auxiliary agent. The combination of 2 µL of 0.5 w/v% D-sorbitol (as AP) and 2 µL of 10 w/v% Tween®20 (as TDA) was found to be most effective in improving the analytical sensitivity of PAHs. The sensitivities of 5-6-ring PAHs with high boiling points increased most when analyzing blank filter papers added with PAHs standard sample or real samples of PM2.5 compared with the samples without the auxiliary agent. When analyzing real samples of PM2.5, the peak areas of 5-ring and 6-ring PAHs in the PM2.5 sample added with the optimized auxiliary agent were 1.40 and 1.96 times that without the auxiliary agent. It is considered that AP in the auxiliary agent covered active sites and protected PAHs undergoing decomposition or adsorption. TDA improved the thermal extraction rate of high boiling point PAHs. When using alternative heat sampling equipment to analyze low concentrations of high boiling point components, the auxiliary agent proposed herein can increase the analytical sensitivity toward the target compounds.

An Avulsed Tooth Detected Prior to Insertion of a Laryngeal Mask Airway.

This case report describes the importance of inspecting the hypopharynx via direct laryngoscopy prior to laryngeal mask airway (LMA) insertion during induction of general anesthesia for dental patients with special needs. A 51-year-old man with cerebral palsy underwent induction of general anesthesia for dental extractions and subsequently was noted to be missing a tooth. Prompt inspection of the airway via direct laryngoscopy revealed the tooth resting within the pharynx, which was subsequently retrieved, prior to insertion of the LMA. Visual inspection of the oropharynx and hypopharynx by laryngoscopy prior to LMA insertion can be useful in preventing accidental aspiration and ingestion of foreign bodies, particularly with certain high-risk patients. Use of laryngoscopy should also be considered if an object is lost or possibly impinging upon the airway.

Dynamics of intracellular phospholipid membrane organization during oocyte maturation and successful vitrification of immature oocytes retrieved by ovum pick-up in cattle.

The objective was to determine if immature bovine oocytes with cumulus cells at the germinal vesicle (GV) stage could be vitrified by aluminum sheets (AS; pieces of sheet-like aluminum foil). Cleavage rates in fertilized oocytes previously vitrified by the AS procedure were higher than those vitrified by a nylon-mesh holder (NM) procedure (89.3 ± 2.1% vs. 65.0 ± 3.7%). Cleaved embryos derived from the AS but not from the NM procedures developed to blastocysts. Furthermore, to investigate the effects of vitrifying GV oocytes on cytoplasmic structure and on the ability to undergo cytoplasmic changes, the intracellular phospholipid membrane (IM) was stained with the lipophilic fluorescent dye, 3,3'-dioctadecyloxa-carbocyanine perchlorate. After vitrification by AS, the IM remained intact relative to that of oocytes vitrified by NM. During in vitro maturation, reorganization of the IM was also undamaged in oocytes vitrified by AS before oocyte maturation, and the IM within oocytes vitrified by the NM procedure was evidently impaired. Finally, vitrification (AS) was used for GV oocytes collected using the ovum pick-up method. A bull calf was born after in vitro production and subsequent embryo transfer. The vitrification techniques described herein should facilitate generation of viable in vitro production bovine blastocysts using oocytes recovered using the ovum pick-up method.