Odor Fingerprinting of Chitosan and Source Identification of Commercial Chitosan: HS-GC-IMS, Multivariate Statistical Analysis, and Tracing Path Study.

Chitosan samples were prepared from the shells of marine animals (crab and shrimp) and the cell walls of fungi (agaricus bisporus and aspergillus niger). Fourier-transform infrared spectroscopy (FT-IR) was used to detect their molecular structures, while headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) was employed to analyze their odor composition. A total of 220 volatile organic compounds (VOCs), including esters, ketones, aldehydes, etc.

Sources of atmospheric oxygenated volatile organic compounds in different air masses in Shenzhen, China.

As precursors of photochemical secondary pollutants, oxygenated volatile organic compounds (OVOCs) play an important role in atmospheric photochemistry. In this study, 23 OVOCs were monitored using a commercial proton transfer reaction time-of-flight mass spectrometer at an urban site in Shenzhen, China. During the campaign, the mean total concentration of OVOCs was 23.

[Effect of exchange of tracheal tube for laryngeal mask airway(LMA) on intratracheal extubation stress response under deep anesthesia level after surgery in elderly patients with hypertension].

Objective: To investigate the effect of exchange of tracheal tube for a laryngeal mask airway (LMA) on intratracheal extubation stress response under deep anesthesia level after surgery in elderly patients with hypertension.

Methods: From October 2008 to June 2009, 40 hypertension patients aged from 65 to 78 years scheduled for upper abdominal surgery were randomly divided into 2 groups, one was extubated intratracheal tube when being awake (group TT, n = 20) and the other was extubated and exchanged for LMA under deep anesthesia (group LM, n = 20). The American Society of Anesthesiologists (ASA) of the patients were I o rII.