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1.
Chin J Integr Med ; 30(3): 195-202, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38374490

RESUMEN

OBJECTIVE: To evaluate the effect and safety of foot baths with Tangbi Waixi Decoction (TW) in treating patients with diabetic peripheral neuropathy (DPN). METHODS: It is a multicenter double-blinded randomized controlled trial. Participants with DPN were recruited between November 18, 2016 and May 30, 2018 from 8 hospitals in China. All patients received basic treatments for glycemic management. Patients received foot baths with TW herbal granules either 66.9 g (intervention group) or 6.69 g (control group) for 30 min once a day for 2 weeks and followed by a 2-week rest, as a therapeutic course. If the Toronto Clinical Scoring System total score (TCSS-TS) ⩾6 points, the patients received a total of 3 therapeutic courses (for 12 weeks) and were followed up for 12 weeks. The primary outcome was change in TCSS-TS score at 12 and 24 weeks. Secondary outcomes included changes in bilateral motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) of the median and common peroneal nerve. Safety was also assessed. RESULTS: Totally 632 patients were enrolled, and 317 and 315 were randomized to the intervention and control groups, respectively. After the 12-week intervention, patients in both groups showed significant declines in TCSSTS scores, and significant increases in MNCV and SNCV of the median and common peroneal nerves compared with pre-treatment (P<0.05). The reduction of TCSS-TS score at 12 weeks and the increase of SNCV of median nerve at 24 weeks in the control group were greater than those in the intervention group (P<0.05). The number of adverse events did not differ significantly between groups (P>0.05), and no serious adverse event was related with treatment. CONCLUSION: Treatment of TW foot baths was safe and significantly benefitted patients with DPN. A low dose of TW appeared to be more effective than a high dose. (Registry No. ChiCTR-IOR-16009331).


Asunto(s)
Diabetes Mellitus , Neuropatías Diabéticas , Plantas Medicinales , Humanos , Neuropatías Diabéticas/tratamiento farmacológico , Baños , Método Doble Ciego , Extractos Vegetales/uso terapéutico
2.
Orthop Surg ; 12(1): 199-209, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32077262

RESUMEN

OBJECTIVES: This study aimed to present the different pattern of intravertebral vacuum cleft (IVC) related to high risk of cement complications in minimally invasive treatments for Kümmell's disease (KD) and relevant treatment strategies. METHODS: A retrospective study from January 2016 to January 2018 was conducted at Wuhan Fourth Hospital and comprised 35 patients with Kümmell's disease. There were seven males and 28 females, and the mean age of the patients was 70.4 years. The patterns of IVC in KD were analyzed. These patients were divided into three groups based on the treatment method used. The treatment methods included long-segment fixation (LSF), posterior short-segment fixation (SSF), and percutaneous kyphoplasty (PKP). We retrospectively reviewed outcomes, including the Oswestry Disability Index (ODI), visual analog scale (VAS) score, anterior height of affected vertebrae, kyphotic Cobb angle, and complications. RESULTS: All patients were followed up for 12-38 months. According to their radiographic appearance we could observe two main patterns of clefts. Pattern I, clefts that were found to be near to the endplate and connected with intervertebral space, the endplate was incomplete. Pattern II, IVC traversed to anterior edge of the vertebral body affected. Both were related to high risk of cement complications in minimal invasive treatments for KD. Good results have been achieved in LSF and SSF groups, the VAS, ODI, anterior height of affected vertebrae and kyphotic Cobb angle showed statistically significant differences between pre- and post-operation and between pre- and final follow-up (P < 0.05). In PKP group, although the VSA and ODI showed statistically significant differences between pre- and post-operation and between pre- and final follow-up (P < 0.05), we could observe that the VSA and ODI rebounded a little at the final follow-up. Cement leakage into intervertebral space occurred in four (44.45%) patients of PKP group. CONCLUSIONS: PKP should be chosen carefully if the IVC of the patient presents to be pattern I or II. LSF and SSF are safe and effective, and can achieve satisfactory correction of kyphosis and vertebral height, with pain relief and improvement in patient's daily life, with few complications.


Asunto(s)
Fijación Interna de Fracturas/métodos , Fracturas por Compresión/cirugía , Fracturas Osteoporóticas/cirugía , Fracturas de la Columna Vertebral/cirugía , Vértebras Torácicas/cirugía , Anciano , Anciano de 80 o más Años , Evaluación de la Discapacidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dimensión del Dolor , Estudios Retrospectivos
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 220: 117103, 2019 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-31146205

RESUMEN

A novel approach to use two-dimensional correlation spectroscopy (2D-COS) to analyze bilinear data is proposed. A phenomenon called Systematic Absence of Cross Peaks (SACPs) is observed in a 2D asynchronous spectrum. Two theorems relevant to SACPs have been derived. The SACP-based 2D-COS method has been successfully applied on analyzing bilinear data from mixed samples (including one model system and two real systems). Implicit isolated peaks can be identified and assigned to different components based on characteristic pattern of SACPs even if the time-related profiles of different components are severely overlapped. Based on the results of SACPs, spectra of pure components can be retrieved. Identification of SACPs can still be achieved in the presence of artifacts. Thus, neither noise nor baseline drift can produce significant influence on the results obtained from the approach described in this paper. We have used several well-established chemometric methods, including N-Findr, VCA, and MCR with various initial settings, on two systems that can be successfully solved using the 2D-COS method. The chemometric methods mentioned above cannot provide correct spectra of pure components because of severe problem of rotational ambiguity derived from severe overlapping of the time-related profiles. Only when the information from SACPs in 2D-COS is used as additional constraints in MCR calculation, correct spectra can be obtained. That is to say, the SACP-based 2D-COS method provides intrinsic information which is crucial in the analysis of chromatographic-spectroscopic and analogous data even if the time-related profiles of different components overlap severely.

4.
Am J Ther ; 25(5): e517-e523, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-26840341

RESUMEN

Etomidate is a widely used hypnotic drug for induction of general anesthesia and sedation, especially in elderly patients and hemodynamically unstable patients. Myoclonus, however, is the most prominent problem during induction of anesthesia with etomidate. Many agents have been used to prevent it and opioid is one of them. This meta-analysis was to evaluate effects of opioids pretreatment for preventing etomidate-induced myoclonus. We searched the PubMed, EMBASE, and the Cochrane Library databases and published studies in English updated to September 2015. Randomized controlled trials of opioids versus placebo/control in patients were included. We evaluated the prophylactic effect of opioids on etomidate-induced myoclonus. All statistical analysis was performed using RevMan 5.2 software. Nine randomized controlled trials involving 604 participants were included. The results indicated that compared with placebo/control, opioids allow more patients to experience no myoclonic movements after etomidate injection [risk ratio (RR) 2.76, 95% confidence interval (CI) 1.75-4.37, P < 0.0001]. The numbers of patients with mild myoclonus [(RR) 0.53, 95% (CI) 0.36-0.78, P = 0.001], moderate myoclonus [(RR) 0.36, 95% (CI) 0.23-0.55, P < 0.00001], and severe myoclonus [(RR) 0.20, 95% (CI) 0.08-0.52, P = 0.0009] after etomidate injection were significantly decreased with the pretreatment of opioids. This meta-analysis suggests that pretreatment with opioids before injecting etomidate was effective for preventing etomidate-induced myoclonus and can reduce the intensity of myoclonus without any adverse effects.


Asunto(s)
Analgésicos Opioides/administración & dosificación , Etomidato/efectos adversos , Hipnóticos y Sedantes/efectos adversos , Mioclonía/inducido químicamente , Mioclonía/prevención & control , Humanos , Ensayos Clínicos Controlados Aleatorios como Asunto , Índice de Severidad de la Enfermedad
5.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(12): 4067-71, 2016 Dec.
Artículo en Chino | MEDLINE | ID: mdl-30256561

RESUMEN

Because of ground observation instruments and other factors, we can not recognize the space target only from the external shape in the image. Since the reflection spectrum of the space target is determined by the surface material of space object, spectral analysis technique can be used for classifying the space objects. Based on the K-nearest neighbor algorithm (KNN), a method called adaptive weight k-local hyperplane (AWKH) is proposed in this paper. The main improvement of the algorithm is that weight discrimination is added in the processes of calculating the hyperplane distance between predicted samples. The algorithm constructs a hyperplane model by using the difference between the groups and within group ratio for the weights of features. In order to verify the classification effectiveness and efficiency of the algorithm, this paper carried out four sets of verification experiments. In the first set of experiments, 9 kinds of common materials were extracted from the database of United State Geological Survey. Then 3 kinds of these materials were mixed into multi-class objections. In the second and third sets of experiments, the spectra of four normal space target materials were mixed in different classes. Then these classes were identified from the visible and near-infrared wave bands. In the fourth set of experiments, four square models of hexahedron were classified by the spectra of their surface material. The experimental results indicate that the AWKH algorithm has more advantages in identification accuracy and effectiveness of the complex samples by comparing with the support vector machine (SVM) method.

6.
Appl Opt ; 54(6): 1267-72, 2015 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-25968186

RESUMEN

To achieve a unidirectional transmission waveguide with miniature dimensions and flexible geometry, we propose a self-guided unidirectional waveguide composed of a chain of gyromagnetic rods. Two configurations of the waveguides were demonstrated. One is of a zigzag chain form, the other is a straight-line chain. These two types of waveguides have very wide one-way edge mode bandwidths. The simulated and experimental results illustrate their extraordinary wideband one-way transmission characteristics. They can also be expected to function as flexible platforms for practical applications because of their thin transverse dimensions and robustness to bending.

7.
Opt Express ; 23(8): 9658-63, 2015 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-25969002

RESUMEN

We experimentally demonstrate a broadband one-way transmission by merging the operating bands of two types of one-way edge modes that are associated with Bragg scattering and magnetic surface plasmon (MSP) resonance, respectively. By tuning the configuration of gyromagnetic photonic crystals and applied bias magnetic field, the fused bandwidth of unidirectional propagation is up to 2 GHz in microwave frequency range, much larger than either of the individual one-way bandwidth associated with Bragg scattering or MSP resonance. Our scheme for broadband one-way transmission paves the way for the practical applications of one-way transmission.

8.
Int J Surg ; 18: 28-33, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25865086

RESUMEN

OBJECTIVE: The number of citations that a paper has received reflects the impact of the article within a particular medical area. Citation analysis concerning the most cited articles have been widely reported in orthopedic surgery and its subspecialties. However, which articles are cited most frequently in orthopedic elbow surgery is unknown. This study aimed to identify and analyze the characteristics of the 50 most cited articles in elbow surgery. METHODS: Science Citation Index Expanded was used to search for citations in 181 journals chosen according to the relevance for elbow publications. The 50 most cited articles in elbow surgery were identified. The title, authors, year of publications, article type, journal source, country, institution, number of citations, decade published, citation density and level of evidence were recorded and analyzed. RESULTS: The 50 most cited articles were published between 1950 and 2010. The 1980s was the most productive decade. The number of citations ranged from 388 to 124. All the articles were written in English and published in nine journals. The majority of articles originated from United States, followed by Canada and United Kingdom. Fracture was the most discussed topic. The majority of the top cited articles were clinical studies, with the remaining basic research. The most common level of evidence was level IV. CONCLUSIONS: Identification of the most cited papers in elbow surgery shows an insight into the historical development of elbow surgery and provides the foundation for further investigations.


Asunto(s)
Codo/cirugía , Ortopedia , Publicaciones Periódicas como Asunto , Bibliometría , Humanos , Estados Unidos
9.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(5): 1429-33, 2014 May.
Artículo en Chino | MEDLINE | ID: mdl-25095453

RESUMEN

A novel calibration transfer method based on stability competitive adaptive reweighted sampling (SCARS) was proposed in the present paper. An informative criterion, i. e. the stability index, defined as the absolute value of regression coefficient divided by its standard deviation was used. And the root mean squared error of prediction (RMSEP) after transfer was also used. The wavelength variables which were important and insensitive to influence of measurement parameters were selected. And then the differences in responses of different instruments or measurement conditions for a specific sample were eliminated or reduced to improve the calibration transfer results. Moreover, in the proposed method, the spectral variables were compressed, making calibration transfer more stable. The application of the proposed method to calibration transfer of NIR analysis was evaluated by analyzing the corn with different NIR spectrometers. The results showed that this method can well correct the difference between instruments and improve the analytical accuracy. The transfer results obtained by the proposed method, orthogonal signal correction (OSC), Monte Carlo uninformative variable elimination (MCUVE) and competitive adaptive reweighted sampling (CARS), respectively, for corn with different NIR spectrometers indicated that the former gave the best analytical accuracy, and was effective for the spectroscopic data compression which can simplify and optimize the transfer process.

10.
Guang Pu Xue Yu Guang Pu Fen Xi ; 34(2): 494-7, 2014 Feb.
Artículo en Chino | MEDLINE | ID: mdl-24822427

RESUMEN

In order to improve the prediction accuracy of quantitative analysis model in the near-infrared spectroscopy of blood glucose, this paper, by combining net analyte preprocessing (NAP) algorithm and radial basis functions partial least squares (RBFPLS) regression, builds a nonlinear model building method which is suitable for glucose measurement of human, named as NAP-RBFPLS. First, NAP is used to pre-process the near-infrared spectroscopy of blood glucose, in order to effectively extract the information which only relates to glucose signal from the original near-infrared spectra, so that it could effectively weaken the occasional correlation problems of the glucose changes and the interference factors which are caused by the absorption of water, albumin, hemoglobin, fat and other components of the blood in human body, the change of temperature of human body, the drift of measuring instruments, the changes of measuring environment, and the changes of measuring conditions; and then a nonlinear quantitative analysis model is built with the near-infrared spectroscopy data after NAP, in order to solve the nonlinear relationship between glucose concentrations and near-infrared spectroscopy which is caused by body strong scattering. In this paper, the new method is compared with other three quantitative analysis models building on partial least squares (PLS), net analyte preprocessing partial least squares (NAP-PLS) and RBFPLS respectively. At last, the experimental results show that the nonlinear calibration model, developed by combining NAP algorithm and RBFPLS regression, which was put forward in this paper, greatly improves the prediction accuracy of prediction sets, and what has been proved in this paper is that the nonlinear model building method will produce practical applications for the research of non-invasive detection techniques on human glucose concentrations.


Asunto(s)
Glucemia/análisis , Algoritmos , Calibración , Hemoglobinas , Humanos , Análisis de los Mínimos Cuadrados , Dinámicas no Lineales , Espectroscopía Infrarroja Corta
11.
Guang Pu Xue Yu Guang Pu Fen Xi ; 33(2): 390-4, 2013 Feb.
Artículo en Chino | MEDLINE | ID: mdl-23697118

RESUMEN

Raman spectroscopy technique could satisfy industrial field measurement requirements because of the advantages of rapidity and nondestructiveness. Thus, It has been widely used in a variety of quantitative and qualitative analysis fields. The volume ration of alcohol and water in alcoholic beverages, i. e. the ethanol content, is a key factor in the detection of the quality of wine products. The development of the detection system for quick, easy and real-time ethanol content measurement is of great significance for national production. In the present paper, net signal analysis method (NAS) was used in the ethanol content quantitative analysis of Raman spectra from the ethanol aqueous solution. The linear regression model was developed between the net signal of ethanol and its concentration. The results showed that the qualitative analysis method based on net signal analysis was superior to the traditional linear regression method such as the MLR method based on the feature peak intensity and the PLS model. It not only improved the prediction accuracy of the model but also enhanced the robustness of the model. Because the model established by the NAS-MLR method is simple and stable, it is possible to develop the portable measurement instruments in future.


Asunto(s)
Bebidas/análisis , Etanol/análisis , Modelos Químicos , Espectrometría Raman , Tecnología de Alimentos , Modelos Lineales
12.
Guang Pu Xue Yu Guang Pu Fen Xi ; 33(3): 780-4, 2013 Mar.
Artículo en Chino | MEDLINE | ID: mdl-23705453

RESUMEN

It is the premise of establishing stable and accurate model to extract useful information from spectrum data in Vis/NIR spectrum analysis technology. ISOMAP is a dimension reduction method, and can effectively extract the intrinsic low dimension from high dimensional data, but is sensitive to noise and neighborhood parameter. In this paper, an improved ISOMAP algorithm, called supervised dimension reduction, is proposed. It guides the construction of the neighborhood graph using correlation owned by spectrum data, and reduces sensitivity to noise and neighborhood parameter. The algorithm was applied to two datasets, and then PLS models were established. The experiment results indicated that the improved algorithm was less sensitive to the neighborhood size and more robust and more topologically stable. In addition, smaller dimension was extracted, and the model precision was improved at the same time.

13.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(9): 2523-7, 2012 Sep.
Artículo en Chino | MEDLINE | ID: mdl-23240431

RESUMEN

Photoplethysmography can be used to noninvasively detect oxygen saturation of human. When detecting by photoplethysmography, because of the disturbance of random noise in the process of signal acquisition, there is high-frequency noise, which affects the final prediction accuracy of oxygen saturation. Therefore empirical mode decomposition(EMD) method based on consecutive mean square error(CMSE) criterion is employed, which can remove high-frequency noise from pulse wave signal. The present paper used a self-developed photoplethysmography acquiring device to obtain the pulse wave signal, employed the above mentioned method to remove high-frequency noise, and adopted frequency spectrum of the signal to evaluate the effect. The results showed that: this method could effectively remove high-frequency noise from pulse wave signal. This would be beneficial for improving the prediction accuracy of oxygen saturation of human.


Asunto(s)
Oxígeno , Fotopletismografía/instrumentación , Algoritmos , Artefactos , Humanos
14.
ScientificWorldJournal ; 2012: 936149, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22645472

RESUMEN

Cancer is a disease that does great harms to the health of human beings. FT-IR spectroscopy could identify variability at the molecular level in biological specimens. It is a rapid and noninvasive method, which could be used intraoperatively to modify surgical procedures. The aim of this paper is to identify and separate cancer from colitis in endoscopic colon biopsies through the use of FT-IR spectroscopy. A total of 88 endoscopic colon samples, including 41 cases of colitis and 47 cases of colon cancer, were obtained. Specimens were placed on an ATR accessory linked to FT-IR spectrometer with a MCT detector for greater stability and sensitivity. Later, specimens were sent for the histological examination as the reference in the spectral analysis. 41 colitis and 47 cancer specimens were compared. Spectra preprocessed with smoothing and normalization were used for discrimination analysis. PCA was processed to simplify the spectrum data set. Naive Bayes classifier model was constructed for diagnostic classification. Leave-one-out cross-validation method was utilized to assess the discrimination results. The sensitivity of FT-IR detection for cancer achieves 97.6%. The results showed that colon cancer could be distinguished from colitis with high accuracy using FT-IR spectroscopy and chemometrics.


Asunto(s)
Biopsia/métodos , Colitis/diagnóstico , Neoplasias del Colon/diagnóstico , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Adulto , Anciano , Teorema de Bayes , Neoplasias del Colon/patología , Endoscopía/métodos , Femenino , Humanos , Masculino , Oncología Médica/métodos , Persona de Mediana Edad , Análisis de Componente Principal , Reproducibilidad de los Resultados
15.
Guang Pu Xue Yu Guang Pu Fen Xi ; 32(3): 642-6, 2012 Mar.
Artículo en Chino | MEDLINE | ID: mdl-22582623

RESUMEN

A small non-invasive measurement system for human blood glucose has been developed, which can achieve fast, real-time and non invasive measurement of human blood glucose. The device is mainly composed of four parts, i. e. fixture, light system, data acquisition and processing systems, and spectrometer. A new scheme of light source driving was proposed, which can meet the requirements of light source under a variety of conditions of spectral acquisition. An integrated fixture design was proposed, which not only simplifies the optical structure of the system, but also improves the reproducibility of measurement conditions. The micro control system mainly achieves control function, dealing with data, data storage and so on. As the most important component, microprocessor DSP TMS320F2812 has many advantages, such as low power, high processing speed, high computing ability and so on. Wavelet denoising is used to pretreat the spectral data, which can decrease the loss of incident light and improve the signal-to-noise ratio. Kernel partial least squares method was adopted to build the mathematical model, which can improve the precision of the system. In the calibration experiment of the system, the standard values were measured by One-Touch. The correlation coefficient between standard blood glucose values and truth values is 0.95. The root mean square error of measurement is 0.6 mmol x L(-1). The system has good reproducibility.


Asunto(s)
Glucemia/análisis , Espectroscopía Infrarroja Corta , Calibración , Humanos , Análisis de los Mínimos Cuadrados , Modelos Teóricos , Reproducibilidad de los Resultados , Relación Señal-Ruido
16.
J Immunol ; 187(11): 5495-9, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-22039303

RESUMEN

Bacillus Calmette-Guérin (BCG), the antituberculosis vaccine, localizes within immature phagosomes of macrophages and dendritic cells (APCs), and avoids lysosomal degradation. BCG-derived antigenic peptides are thus inefficiently processed by APCs, and we investigated alternate mechanisms of Ag processing. Proteomics identified that BCG phagosomes are enriched for nicastrin, APH, and presenilin components of γ-secretase, a multimeric protease. Using an in vitro Ag presentation assay and BCG-infected APCs, we found γ-secretase components to cleave BCG-derived Ag85B to produce a peptide epitope, which, in turn, primed IL-2 release from Ag85B-specific T cell hybridoma. siRNA knockdown or chemical inhibition of γ-secretase components using L685458 decreased the ability of BCG or Mycobacterium tuberculosis-infected APCs to present Ag85B. In addition, L685485 inhibition of γ-secretase led to a decreased ability of BCG-dendritic cells to immunize mice and induce Ag85B-specific CD4 T cells in vivo. Because BCG and M. tuberculosis sequester within APCs preventing immune recognition, γ-secretase components appear to fortuitously process the immunodominant Ag85B, facilitating immune recognition.


Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/inmunología , Presentación de Antígeno/inmunología , Antígenos Bacterianos/inmunología , Vacuna BCG/inmunología , Epítopos de Linfocito T/inmunología , Activación de Linfocitos/inmunología , Linfocitos T/inmunología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Animales , Células Presentadoras de Antígenos/inmunología , Células Presentadoras de Antígenos/metabolismo , Células Presentadoras de Antígenos/microbiología , Antígenos Bacterianos/metabolismo , Endopeptidasas/inmunología , Endopeptidasas/metabolismo , Técnica del Anticuerpo Fluorescente , Antígenos de Histocompatibilidad Clase II/inmunología , Glicoproteínas de Membrana/inmunología , Glicoproteínas de Membrana/metabolismo , Ratones , Ratones Endogámicos C57BL , Mycobacterium bovis/inmunología , Mycobacterium bovis/metabolismo , Fagosomas/inmunología , Fagosomas/metabolismo , Presenilinas/inmunología , Presenilinas/metabolismo , Proteómica , Linfocitos T/metabolismo
17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 31(6): 1481-5, 2011 Jun.
Artículo en Chino | MEDLINE | ID: mdl-21847914

RESUMEN

Accurate measurement of human blood glucose concentration is very significant for the treatment of diabetes. In the present paper, the method of continuum power regression can improve the predictive accuracy of noninvasive measurement of human blood glucose concentration with near infrared spectroscopy. This method is the expansion of the traditional method of partial least squares (PLS). It can achieve simpleness, and can significantly improve predictive accuracy when the power coefficient is fit. Using the method, quantitative analysis models of four ingredient experiment and noninvasive experiment of body were established, and these models can be used to predict the predictive samples. Experimental results show that compared with the PLS, the quantitative analysis models of this method not only can improve predictive accuracy, but also can set different power coefficient for different individuals to achieve the best results of models. According to different individuals, the power coefficient can be selected flexibly, which is of great value to the research on noninvasive measurement of human blood glucose concentration with near infrared spectroscopy.


Asunto(s)
Glucemia/análisis , Espectroscopía Infrarroja Corta , Humanos , Análisis de los Mínimos Cuadrados , Modelos Teóricos
18.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(8): 2115-9, 2010 Aug.
Artículo en Chino | MEDLINE | ID: mdl-20939319

RESUMEN

In the study of non-invasive measurement of human blood glucose concentration with near-infrared spectroscopy, the partial robust M-regression (PRM) is proposed in the present paper to solve the robustness of calibration model affected by outliers existing in the spectra data set. While keeping the good properties of M-estimators if an appropriate weighting scheme is chosen, PRM inherits the speed of computation and easy realization of the iterative reweighted partial least squares (IRPLS) algorithm, but is robust to all types of outliers. With the pretreatment of spectra based on PRM, the root mean square error of prediction (RMSEP) of calibration model was presented and compared with partial least squares (PLS). Experimental results show that the robust calibration model PRM produces better prediction of glucose than the model of PLS when the components of the samples increase which is significant for non-invasive prediction of blood glucose levels.


Asunto(s)
Glucemia , Espectroscopía Infrarroja Corta , Algoritmos , Calibración , Humanos , Análisis de los Mínimos Cuadrados
19.
Biosens Bioelectron ; 26(2): 536-41, 2010 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-20692151

RESUMEN

Horseradish peroxidase (HRP) was successfully incorporated into the laponite/chitosan (Chit)-modified glassy carbon electrode (GCE) using step-by-step self-assembly. The self-assembly processes were monitored by X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectra (EIS). Direct electrochemistry and electrocatalysis of the self-assembled HRP were investigated. Cyclic voltammetry of HRP/laponite/Chit/GCE, in anaerobic phosphate buffer solution (0.025 M PBS, pH 7.0), displayed a pair of stable and quasi-reversible peaks at potentials Epa=0.024 V and Epc=-0.132 V vs. SCE, attributed to the HRP-Fe(III)/HRP-Fe(II) redox couple. The electrochemical reaction of the HRP/laponite/Chit/GCE exhibited a surface-controlled electrode process. The electron transfer rate constant was estimated to be 1.82 s(-1). The self-assembled HRP maintained its biological activity and exhibited an excellent electrocatalytic performance for the reduction of H2O2 with fast amperometric response (10 s), broad linear range (2.9×10(-5) to 1.4×10(-3) M), good sensitivity (19.7±0.5 mA M(-1) cm(-2)) and low detection limit (5×10(-6) M) at a signal-to-noise ratio of 3. Moreover, the inhibitory of sulfide to the self-assembled HRP was also investigated.


Asunto(s)
Técnicas Biosensibles/instrumentación , Quitosano/química , Conductometría/instrumentación , Peroxidasa de Rábano Silvestre/química , Peróxido de Hidrógeno/análisis , Silicatos/química , Sulfuros/química , Inhibidores Enzimáticos/química , Enzimas Inmovilizadas/química , Diseño de Equipo , Análisis de Falla de Equipo , Peróxido de Hidrógeno/química , Indicadores y Reactivos
20.
Guang Pu Xue Yu Guang Pu Fen Xi ; 30(5): 1310-4, 2010 May.
Artículo en Chino | MEDLINE | ID: mdl-20672624

RESUMEN

Vis/NIR spectroscopy technology is capable of analyzing the content of biochemical parameter in folium rapidly and nondestructively. In the process of spectrum analysis, the variations in path-length between different samples exist, with the random light scattering and leaf thickness perturbations, which influence the precision of quantitative analysis model. In order to resolve this problem, an improved path-length correction method based on Extended Multiplicative Scattering Correction is presented. In this paper, firstly the theory of EMSC algorithm is deduced. EMSC method incorporates both chemical terms and wavelength functions to help realize the efficient separation of path-length and interest concentration. Secondly two experiments were implemented to demonstrate the validity of the method. In Experiment 1, sixteen samples of different thickness but almost the same chlorophyll content were selected, and how the path-length affects the spectrum was compared, after EMSC preprocessing, the variable coefficient of spectrum could approach the repeatability error of spectrometer. In Experiment 2, thirty-two samples of different thickness and chlorophyll content were selected. PLS model established using cross validation was employed to evaluate the efficiency of the presented algorithm. Before the preprocessing, the root mean squared error of prediction is 3.9 SPAD with 5 principal components. After preprocessing, the predicted root mean squared error is 2.2 SPAD with 12 principal components. The results indicate that the improved EMSC preprocessing method could exactly eliminate the spectrum difference caused by the path-length variations between different foliums, enhance the sensitivity of concentration and spectral data, and increase the precision of calibrated model.


Asunto(s)
Hojas de la Planta , Espectroscopía Infrarroja Corta , Algoritmos , Calibración , Clorofila/análisis , Modelos Teóricos
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