A Versatile SERS Sensor for Multiple Determinations of Polycyclic Aromatic Hydrocarbons and Its Application Potential in Analysis of Fried Foods

Polycyclic aromatic hydrocarbons (PAHs), due to their high hydrophobicity, have low affinity for metallic SERS-active surfaces, which leads to their low SERS detection sensitivity. Various functional groups have been used to improve the affinity of metallic substrates towards the target PAHs. However, a large portion of the signals generated from the “first-layer effect” of the functionalized substrates may complicate the spectrum, leading to a distortion in the assignment of the intrinsic SERS fingerprints of PAHs. In this study, a SERS sensor composed of Au nanoparticles (AuNPs) and reoxidized graphene oxide (rGO) was developed for the simultaneous determination of 16 EPA priority PAHs. The synthesis of the rGO/AuNP substrate can be realized without a complicated modification process. All the 16 PAHs could be identified based on their characteristic peaks in the presence of the composited substrate, with estimated LOD as low as 0.2–2 ng·mL−1. The binary linear regression was optimized as the fitting model for all PAHs except for benzo(k)fluoranthene, with the linear correlation coefficient ranging from 0.9889 to 0.9997. Based on the developed SERS substrates and sample pretreatment, the characteristic SERS peaks of four PAHs in Chinese traditional fried food (youtiao) were identified without any background interference. The whole detection process only takes approximately 15 minutes. The results demonstrate the potential of the multicomponent on-field detection of PAHs.

Optimal Partner Wavelength Combination Method Applied to NIR Spectroscopic Analysis of Human Serum Globulin

Human serum globulin (GLB), which contains various antibodies in healthy human serum, is of great significance for clinical trials and disease diagnosis. In this study, the GLB in human serum was rapidly analyzed by near infrared (NIR) spectroscopy without chemical reagents. Optimal partner wavelength combination (OPWC) method was employed for selecting discrete information wavelength. For the OPWC, the redundant wavelengths were removed by repeated projection iteration based on binary linear regression, and the result converged to stable number of wavelengths. By the way, the convergence of algorithm was proved theoretically. Moving window partial least squares (MW-PLS) and Monte Carlo uninformative variable elimination PLS (MC-UVE-PLS) methods, which are two well-performed wavelength selection methods, were also performed for comparison. The optimal models were obtained by the three methods, and the corresponding root-mean-square error of cross validation and correlation coefficient of prediction (SECV, RP,CV) were 0.813 g·L-1 and 0.978 with OPWC combined with PLS (OPWC-PLS), and 0.804 g L-1 and 0.979 with MW-PLS, and 1.153 g L-1 and 0.948 with MC-UVE-PLS, respectively. The OPWC-PLS and MW-PLS methods achieved almost the same good results. However, the OPWC only contained 28 wavelengths, so it had obvious lower model complexity. Thus it can be seen that the OPWC-PLS has great prediction performance for GLB and its algorithm is convergent and rapid. The results provide important technical support for the rapid detection of serum.

Optimal Partner Wavelength Combination Method Applied to NIR Spectroscopic Analysis of Human Serum Globulin

Human serum globulin (GLB), which contains various antibodies in healthy human serum, is of great significance for clinical trials and disease diagnosis. In this study, the GLB in human serum was rapidly analyzed by near infrared (NIR) spectroscopy without chemical reagents. Optimal partner wavelength combination (OPWC) method was employed for selecting discrete information wavelength. For the OPWC, the redundant wavelengths were removed by repeated projection iteration based on binary linear regression, and the result converged to stable number of wavelengths. By the way, the convergence of algorithm was proved theoretically. Moving window partial least squares (MW-PLS), a well-performed wavelength selection method, was also performed for comparison. The optimal models were obtained by the two methods, and the corresponding root-mean-square error of cross validation and correlation coefficient of prediction (SECV, RP,CV) were 0.813 g·L-1 and 0.978 with OPWC combined with PLS (OPWC-PLS), and 0.804 g L-1 and 0.979 with MW-PLS, respectively. The two methods achieved almost the same good results. However, the OPWC only contained 28 wavelengths, so it had obvious lower model complexity. Thus it can be seen that the OPWC-PLS has great prediction performance for GLB and its algorithm is convergent and rapid. The results provide important technical support for the rapid detection of serum.

Optimal Partner Wavelength Combination Method Applied to NIR Spectroscopic Analysis of Human Serum Globulin

Human serum globulin (GLB), which contains various antibodies in healthy human serum, is of great significance for clinical trials and disease diagnosis. In this study, the GLB in human serum was rapidly analyzed by near infrared (NIR) spectroscopy without chemical reagents. Optimal partner wavelength combination (OPWC) method was employed for selecting discrete information wavelength. For the OPWC, the redundant wavelengths were removed by repeated projection iteration based on binary linear regression, and the result converged to stable number of wavelengths. By the way, the convergence of algorithm was proved theoretically. Moving window partial least squares (MW-PLS), a well-performed wavelength selection method, was also performed for comparison. The optimal models were obtained by the two methods, and the corresponding root-mean-square error of cross validation and correlation coefficient of prediction (SECV, RP,CV) were 0.813 g·L-1 and 0.978 with OPWC combined with PLS (OPWC-PLS), and 0.804 g L-1 and 0.979 with MW-PLS, respectively. The two methods achieved almost the same good results. However, the OPWC only contained 28 wavelengths, so it had obvious lower model complexity. Thus it can be seen that the OPWC-PLS has great prediction performance for GLB and its algorithm is convergent and rapid. The results provide important technical support for the rapid detection of serum.

Circulating microRNA-378 levels serve as a novel biomarker for assessing the severity of coronary stenosis in patients with coronary artery disease

Background: Circulating microRNAs (miRNA) are steady preserved in blood plasma. Multiple evidences have shown that miRNAs play a crucial role in cardiovascular disease including miRNA-378, which has been illustrated to participate in diverse physiological and pathological processes of cardiovascular disease. In the present study, we aim to explore the expression of plasma miRNA-378 and its clinical significance in patients with coronary artery disease (CAD). Methods: MiRNA-378 expression in blood plasma was performed by quantitative real-time PCR (qRT-PCR) in 215 CAD patients and 52 matched controls of healthy populations. Medical information of all patients including the results of coronary angiography (CAG) was acquired through hospital information system (HIS). Spearman’s correlation, binary linear regression, and covariance analysis were used to examine the association between miRNA-378 and relative clinical risk factors. Receiver operating characteristic curve analysis was applied to evaluate the value of miRNA-378 in predicting the disease severity of coronary lesion. Results: Plasma miR-378 expression was significantly down-regulated in CAD patients compared with healthy controls. Relative miR-378 level was shown conversely correlated with Gensini score, which present the severity of coronary artery lesions. Moreover, it is indicated that miR-378 expression can effectively distinguish patients with or without coronary artery stenosis. Conclusions: Plasma miR-378 levels appear to be a promising non-invasive biomarker, but require to be further validated by a large cohort study in future.

Error Analysis in Determination of Density and Temperature of Saline Solution Using Fiber Optic Photoacoustic Transducer Coated with MoS2-PDMS Composite

Regarding the ultrasound determination of density-dependent salinity in seawater, a miniature broadband (up to ~12.8 MHz at 6 dB bandwidth) fiber-tip photoacoustic transducer coated with an ~68.32 μm thick MoS2-polydimethylsiloxane (PDMS) composite was developed for simultaneously measuring the temperature and density of laboratory saline solutions, along with a piezoelectric transducer (PZT) for ultrasound detection. The two parameters, respectively, ranging 20 °C to 50 °C and from 0.99 g/cm3 to 1.10 g/cm3 were measured and then extracted based on the regressive dependence on the propagation speed and attenuation of the ultrasonic wave. In terms of the established linear regression model and estimated regression characteristic parameters, the calculated temperature and density results, respectively, exhibited the extended uncertainty values of 1 °C and 1.08 × 10−3 g/cm3 (k = 2.132), accompanied with an excellent goodness of fit (R2 > 0.97) and significance of the binary linear regression (F >> F0.01). The highly consistent experimental data confirmed the accuracy of our method, thus suggesting the potential of measuring salinity in seawater using compact fiber-optic photo-induced ultrasound scheme.

Aplicación de la Auditoría en las MyPEs del Ecuador: Un estudio de la demanda

<p>La auditoría un tema abordado y aplicado en las Empresas Públicas y Privadas, grandes o pequeñas reguladas y no por órganos de control en la República del Ecuador. Las Pequeñas y Mediana Empresas (PyMEs) al no ser obligadas, no aplican, porque un gran porcentaje de ellas son empresas personales, familiares o societarias, no cuentan con una estructura organizacional, contable y procedimientos adecuados de control financiero y administrativo. La investigación tiene el objetivo de identificar cuáles son los factores que determinan la aplicación de la auditoría en las MyPEs a partir de la determinación de la demanda voluntaria de una auditoría. Se usa el método descriptivo, analítico y estadístico, a través de la revisión bibliográfica y la regresión lineal binaria a datos de la última Encuesta Nacional a Empresas con sus establecimientos y Microempresa. Se demuestra que H1. La aplicación de una auditoría financiera y de gestión, está medida por la obligatoriedad de llevar contabilidad y viene asociada a la naturaleza jurídica y al costo del servicio de una auditoría; y, H2. Si la auditoría no es obligatoria entonces es necesario que las instituciones reguladoras y la universidad jueguen el papel motivador. Se concluye, que existe la probabilidad de contratación de servicios de auditoría voluntariamente porque ayuda al logro de los objetivos y sirve como un elemento importante para el administrador en la toma de decisiones y tener la certeza de la situación financiera y la realidad del negocio, basados en las conclusiones y recomendaciones del informe de auditoría con base en los hallazgos y juicios de valor que emite el profesional auditor.</p><p> </p><p><strong>Descriptores claves:</strong> <em>Control interno, gestión, hallazgos, juicios de valor, medidas correctivas</em></p><p> </p><p> </p><p align="center"><strong>ABSTRAC</strong></p><p>The audit is an issue addressed and applied in Public and Private Enterprises, large or small regulated and not by control bodies in the Republic of Ecuador. Small and Medium Enterprises (SMEs) are not obliged, do not apply, because a large percentage of them are personal, family or corporate companies, do not have an organizational structure, accounting and adequate procedures for financial and administrative control. The objective of the research is to identify the factors that determine the application of the audit in the MSEs from the determination of the voluntary demand for an audit. The descriptive, analytical and statistical method is used, through the bibliographic review and the binary linear regression to data of the last National Survey to Companies with their establishments and Microenterprise. It is shown that H1. The application of a financial and management audit is measured by the obligation to keep accounting and is associated with the legal nature and cost of the service of an audit; Y, H2. If the audit is not mandatory then it is necessary that the regulatory institutions and the university play the motivating role. It is concluded that there is a probability of hiring audit services voluntarily because it helps the achievement of the objectives and serves as an important element for the manager in making decisions and having the certainty of the financial situation and the reality of the business based In the conclusions and recommendations of the audit report based on the findings and value judgments issued by the auditor.</p><p> </p><p><strong><em>Keywords:</em></strong><em> internal control, management, findings, value judgments, corrective measures</em></p>

Measurement Error Correction of y Coordinate in Three Dimensional Localization of Tomatoes Using Binocular Stereo Vision

Accuracy three dimensional coordinates of fruits and vegetables are very important to harvesting robots to harvest fruits and vegetables correctly. To decrease the measurement errors of the y coordinates of tomatoes, we analyzed the measurement errors of y coordinate acquired using binocular stereo vision based on three stereo matching methods. These three stereo matching methods were centroid-based, area-based, and combination stereo matching methods. After stereo matching, the three dimensional coordinates of tomatoes could be acquired based on the triangle ranging principle. Tests of 225 pairs of stereo images of three plastic balls used as normal balls acquired at the distances from 300 to 1000 mm showed that the ranges of the measurement errors of y coordinate acquired based on three stereo matching methods changed with the image acquisition distances obviously. Moreover, the measurement errors of y coordinate appeared linear decreasing trends approximately. Therefore, binary linear regression models were set up to reduce the ranges of the measurement errors of y coordinate of three balls. These models were used as correction models of the measurement values of y coordinate and were helpful to reduce the measurement errors of y coordinate. However, there were owe correction and overcorrection conditions when the image acquisition distances were smaller and larger than 750 mm separately. Then, the correction models based on piecewise binary linear regression were used to solve this problem. The ranges of the measurement errors of y coordinate were reduced further. Tests of 225 pairs of stereo images of three tomatoes acquired at the distances from 300 to 1000 mm showed that the ranges of the measurement errors of y coordinate acquired based on three stereo matching methods were separately from [-20.9, -6.6], [-19.9, -3.44], [-19.9, -3.48] mm to [-6.84, -0.06], [-5.84, -0.82], [-5.85, -0.83] mm after the correction using the piecewise binary linear regression models. It proved that the piecewise binary linear regression models were helpful to reduce the measurement errors of y coordinate in three dimensional localization of tomatoes using binocular stereo vision.