RESUMO
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., were identified as the odor fingerprinting components of chitosan for the first time. A principal component analysis (PCA) revealed that chitosan could be effectively identified and classified based on its characteristic VOCs. The sum of the first three principal components explained 87% of the total variance in original information. An orthogonal partial least squares discrimination analysis (OPLS-DA) model was established for tracing and source identification purposes, demonstrating excellent performance with fitting indices R2X = 0.866, R2Y = 0.996, Q2 = 0.989 for independent variable fitting and model prediction accuracy, respectively. By utilizing OPLS-DA modeling along with a heatmap-based tracing path study, it was found that 29 VOCs significantly contributed to marine chitosan at a significance level of VIP > 1.00 (p < 0.05), whereas another set of 20 VOCs specifically associated with fungi chitosan exhibited notable contributions to its odor profile. These findings present a novel method for identifying commercial chitosan sources, which can be applied to ensure biological safety in practical applications.
RESUMO
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. The data of mean arterial pressure (MAP), heart rate(HR), pulse oxygen saturation (SPO(2)), end-tidal carbon dioxide tension (P(ET)CO(2)) and rate pressure product(RPP) were recorded before induction of anesthesia (T(0)), suction (T(1)) and at 0 (T(2)), 5(T(3)), and 10 (T(4)) and 15 min (T(5)) after extubation tracheal tube or LMA in two groups. The indices mentioned above also were recorded before and after extubation in group LM. Blood samples were taken at T(0), skin incision, T(2), T(3), for determination of serum concentrations of blood glucose and cortisol. The airway adverse events in the recovery period were recorded. RESULTS: Compared with group LM, MAP, HR and RPP were significantly higher at T(1), T(2), T(3) than T(0) in group TT (P < 0.05). There was no significant difference in the indices mentioned above during extubated intratracheal tube and exchanged for LMA under deep anesthesia in group LM (P > 0.05). The incidence rate of glossoptosis in group TT was significantly higher than those in group LM (P < 0.01), while complications, such as cough, bucking, breath holding during the recovery stage in group TT were more than those in group LM (P < 0.05). Compared with the baseline value, blood glucose and cortisol concentration level were significantly increased in group TT than in group LM (P < 0.01). CONCLUSIONS: Exchange of tracheal tube for LMA under deep anesthesia during recovery stage can decrease the stress response during the recovery stage and attenuate the harmful response of respiratory tract. It is suitable for the elderly patients with hypertension.