[Quantitative Analysis of Heave Mental Ion Based on Portable NIR Spectrometer].

By virtue of the characters of rapid analysis and simple pretreatment, near infrared reflectance spectroscopy technique is widely used in agriculture, medicine, environment, petrochemical and other fields. To satisfy the rapid on-site identification and analysis, portable near-infrared spectrometers have gained more and more attention. Because near infrared reflectance spectroscopy technique also is a green tool for multi-component analysis, the paper aims at investigating the feasibility for simultaneous quantitative analysis of various heavy metal ions in dilute solution using portable near infrared spectrometer. First, amino modified polymerized starch was used as adsorbent to enrich nickel ions and copper ions in diluted solution. Then, the diffuse reflectance spectra of amino modified polymerized starch samples were measured directly by portable near-infrared spectrometer. Furthermore, with the help of spectral preprocessing methods and partial least-squares regression, quantitative models were built from the near infrared diffuse reflectance spectra of amino modified polymerized starch enriched with heavy metal ions and reference concentrations. At last, the stability of the models was proved through cross validation and external validation. The results show that nickel ions and copper ions in diluted solution can be efficiently enriched by amino modified polymerized starch in the presence of other interfering ions. The adsorption rates for nickel ions and copper ions are 99.5% and 99.8%, respectively. Two robust models can be achieved after spectra processing and partial least squares regression. The spectra processing methods contains Continuous wavelet transform and multiplicative scatter correction combined with Savitzky-Golay. The obtained corresponding correlation coefficients of the two robust models are 0.981 9 and 0.965 4, respectively. Thus, simultaneous quantitative analysis of nickel ions and copper ions in the mixed diluted solution was achieved, and the detectable concentrations of nickel ions and copper ions are both as low as 3.0 mg·L(-1). The method not only improves the sensitivity of near infrared reflectance spectroscopy technique, but also demonstrates the feasibility for simultaneous quantitative determination of various heavy metal ions by using portable near infrared spectrometer. Moreover, the method may be a useful exploration to further broaden the application of near infrared reflectance spectroscopy technique.

[Analysis of the incidence of syncope and the influencing factors of death in patients with cardiovascular critical emergency].

OBJECTIVE: To observe the incidence of syncope in patients with acute and critical cardiovascular diseases and to explore the risk factors of death. METHODS: 925 cases of acute heart failure, acute myocardial infarction, pulmonary embolism, arrhythmia and aortic dissection rupture who participated in Prospective, Multi-Center Registered Research Project for Chinese Syncope Patients from March 2018 to March 2020, admitted to the department of emergency of Nanyang Second General Hospital were selected as the research objects. The incidence and mortality of syncope were recorded, and the patients were divided into syncope group and non-syncope group according to whether they were accompanied by syncope or not. The incidence of syncope in male and female patients with different cardiovascular critical diseases, the age and mortality of cardiovascular critical patients with syncope or not were analyzed and compared. Multivariate Logistic regression analysis was used to analyze the risk factors of death, and receiver operating characteristic curve (ROC curve) was drawn to evaluate the predictive value of risk factors on the prognosis of patients. RESULTS: The incidence of syncope in 5 kinds of cardiovascular critical patients from high to low was: acute myocardial infarction 3.03% (28/925), arrhythmia 2.70% (25/925), pulmonary embolism 1.51% (14/925), aortic dissection rupture 1.41% (13/925), acute heart failure 0.65% (6/925), with statistically significant differences (χ2 = 10.765, P = 0.010). There was no significant difference in the incidence of syncope between male and female patients with pulmonary embolism, aortic dissection rupture, acute myocardial infarction, arrhythmia and acute heart failure. The age of patients with aortic dissection rupture, acute myocardial infarction and arrhythmia in syncope group were significantly higher than those in non-syncope group [aortic dissection rupture (years old): 66.29±15.64 vs. 57.63±14.23, acute myocardial infarction (years old): 69.55±15.13 vs. 62.10±15.75, arrhythmia (years old): 70.48±14.93 vs. 60.29±16.31, all P < 0.05]. The mortality of patients with pulmonary embolism, aortic dissection rupture, acute myocardial infarction, arrhythmia, acute heart failure in syncope group were significantly higher than those in non-syncope group [pulmonary embolism: 5.81% (5/86) vs. 0.95% (8/839), aortic dissection rupture: 4.65% (4/86) vs. 0.60% (5/839), acute myocardial infarction: 4.65% (4/86) vs. 1.19% (10/839), arrhythmia: 2.33% (2/86) vs. 0.95% (8/839), acute heart failure: 2.33% (2/86) vs. 0.60% (5/839), all P < 0.05]. Multivariate Logistic regression analysis showed that age [odds ratio (OR) = 2.158, 95% confidence interval (95%CI) was 0.921-4.785, P = 0.000], pulmonary embolism (OR = 15.391, 95%CI was 8.904-27.314, P = 0.001), aortic dissection rupture (OR = 13.079, 95%CI was 6.237-25.509, P = 0.000), acute myocardial infarction (OR = 18.826, 95%CI was 10.420-32.921, P = 0.000), syncope (OR = 4.940, 95%CI was 1.764-9.287, P = 0.000) were risk factors for the prognosis of patients with acute and critical cardiovascular diseases. ROC curve analysis showed that syncope had a certain predictive value for 28-day prognosis of patients [the area under the ROC curve (AUC) = 0.760, P = 0.000], when the cut-off value was 4.12, the sensitivity was 88.51%, the specificity was 78.05%, the positive predictive value was 81.31%, and the negative predictive value was 84.27%. CONCLUSIONS: Syncope is an independent risk factor of death in patients with acute and critical cardiovascular diseases. For patients with syncope as the chief complaint, we should quickly identify the types of acute and critical diseases and assess the risk of sudden death.

Investigating the Structural Change in Protein Aqueous Solution Using Temperature-Dependent Near-Infrared Spectroscopy and Continuous Wavelet Transform.

The circulatory protein, human serum albumin (HSA), is widely used as a model protein for the study of protein structure. In this work, the structures of human serum albumin in aqueous solutions are studied using temperature-dependent near-infrared (NIR) spectroscopy with the aid of continuous wavelet transform (CWT). Near-infrared spectra of human serum albumin solutions with different concentrations were measured over a temperature range of 30-85 ℃. Then, continuous wavelet transform was performed on the spectra to enhance the resolution. As a result of the resolution enhancement, spectral bands around 4361, 4521, 4600 and 4260 cm-1 were extracted from the overlapping low-resolution signals. The four bands can be assigned to the protein structures of α-helix, ß-sheet, an intermediate state and side chains, respectively. The variations in intensity of the bands around 4361 and 4521 cm-1 with temperature show that the increase of temperature leads to the loss of α-helical structure but the formation of ß-sheet, and the denaturation temperature of human serum albumin is about 55 ℃. The variation of the band around 4600 cm-1 indicates that the temperature-induced unfolding process of human serum albumin occurs through a stable intermediate state, and a significant change in the microenvironment of the side chains about 63 ℃ is observed from the variation of the band around 4260 cm-1. On the other hand, the transformed spectra in the region of 8000-5600 cm-1 provide an explicit evidence for the structural changes of water during the process of protein denaturation, and the unfolding process of HSA can be reflected by these changes.

Multilevel analysis of temperature dependent near-infrared spectra.

Quantitative spectra-temperature relationship (QSTR) between near-infrared (NIR) spectra and temperature has been used for quantitative determination of the compositions in mixtures. In this work, QSTR is studied using multilevel simultaneous component analysis (MSCA) and the spectral data of the samples with different concentrations measured at different temperatures. MSCA model contains a between-individual model describing the differences between the individuals and a within-individual model capturing the differences within the data of all the individuals. NIR spectra of five different compositions (water-ethanol-isopropanol) measured at seven temperatures were analyzed. A between-temperature model describing the effect of temperature and a within-temperature model describing the variation of concentration were obtained, from which QSTR model is established and quantitative analysis is achieved. Furthermore, the difference between the between-temperature or within-temperature models of different mixtures is used to study the composition of the solvent.