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Cross striation in human permanent and deciduous enamel measured with confocal Raman microscopy
摘要： Dental enamel is the most mineralized tissue in the human body and has a very complex organization. The aim of the present study was to evaluate chemical composition and orientation of crystals in human enamel cross striation using confocal Raman microscope. Slices of teeth were prepared and scanned using a confocal Raman microscope. Cross striation spacing was calculated according to the variation of PO4 3? peak intensity. The measurements showed a characteristic length between two cross striations of 2.70 (SD 0.43) μm for permanent teeth and 1.75 (SD 0.37) for deciduous teeth. Ratios between OH and PO4 3? peaks, for 0 and 90 degrees angulation, are, respectively, 9.18 (SD 0.80) and 44.74 (SD 3.12) for decidual teeth, and 11.72 (SD 1.46) and 22.12 (SD 3.15) for adult teeth. This confirmed that the hydroxyapatite crystal is well oriented along the enamel prism, as reported in the literature, but with a significant increase in deciduous teeth. K‐mean cluster binary images were calculated to compare the ratio of the centroid peaks of the cross striation zone and inter cross striation material. The regions corresponding to inner prism, included cross striations, are more mineralized than the outer part of enamel prism. In the prism, the Pearson correlation test was performed based on the intensity of hydroxyapatite characteristic peaks (ν1 PO4 3?, ν1 CO3 2?, and OH). The variations were well correlated: These results indicated that cross striations corresponded to the variation of hydroxyapatite concentration and not to a variation of crystals orientation.
关键词： Raman microscopy,cross striation,enamel prism,K‐mean cluster analysis,decidual teeth
更新于2025-09-23 15:23:52
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On-line measurement of fluorescent aerosols near an industrial zone in the Yangtze River Delta region using a wideband integrated bioaerosol spectrometer
摘要： In this work, we present on-line fluorescent aerosol measurements by the wideband integrated bioaerosol spectrometer (WIBS-4A) near an industrial zone in Nanjing, a megacity in the Yangtze-River-Delta (YRD) region. The fieldwork was conducted from April 1 to May 8, 2014. A TSI. 3321 aerosol-particle-sizer (APS) was simultaneously deployed to measure the total number size distribution of aerosol with diameter from 0.8–20 μm. Both WIBS-4A and APS reported similar number concentration and temporal profiles (R2 = 0.72). However, the daily average number of potential bioaerosols was only 0.5 ± 0.2% of the total particles detected by the WIBS-4A and displayed a completely different diurnal profile from that of APS. In addition, WIBS-4A can only provide integrated fluorescent signals, which strongly limited the potential to specifically identify the bioaerosols. Accordingly, hierarchical-agglomerative-cluster-analysis (HACA) was utilized to identify and speciate the potential bioaerosols from the WIBS-4A dataset. By maximizing the total distances among all potential cluster centers, a 12-cluster solution was accepted as the optimum result. These clusters were further identified according to their fluorescent signatures, size, and morphology, i.e., non-bioaerosols, bacteria, and fungal spores and/or pollen fragments. Bacteria were the dominant bioaerosol species detected in this work. The diurnal profiles of bioaerosols correlated very well with relatively humidity (RH), reaching daily maxima around 3 AM~6 AM, indicating the presence of humidity controlled bioaerosol emission mechanism, i.e., bacteria may flourish under moderate ambient temperature, RH, and the absence of UV radiation. The size- and AF-distributions of bioaerosols indicated that bioaerosols normally varied substantially in size and assumed a rather irregular shape. Although the number concentration of bioaerosols was relatively small, most bioaerosols can efficiently serve as ice nuclei by providing rough and irregular surfaces, verified by the observation results. Therefore, WIBS-4A measurements can still be informative for investigations of bioaerosols in the atmosphere, especially when HACA method was incorporated into the data processing.
关键词： Hierarchical agglomerative cluster analysis,WIBS-4A,Ice nuclei,Cloud condensation nuclei,Primary biological aerosol
更新于2025-09-23 15:23:52
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Innovation capability, network embeddedness and economic performance: profiling solar power innovators in China
摘要： This paper discusses the technological upgrading of China in photovoltaics technology. It explores the patterns of innovation and network embeddedness and their impact on economic performance at the firm level. Identifying the main innovators over 1995–2014 with patent and market share indicators, the landscape of their activities is inspected through two hierarchical cluster analyses in parallel: first, against the quantity, quality and diversity of patents, and second, against global-integration, component-size and position in technological knowledge networks. The resulting clusters are cross-related to understand their interrelations with age, size, turnover and productivity of actors. The multivariate analysis of variance shows a significant relationship between turnover and productivity. Global-integration in small-world networks is significantly related with economic performance. Quality of innovation shows higher importance than quantity and diversity. While specialisation in high-tech fields has positive impact on turnover, production-oriented firms with low-tech focus have higher productivity.
关键词： patent profiles,MANOVA,productivity,cluster analysis,concurrency matrix,technological upgrading,China,emerging economy,innovation system,solar photovoltaics,economic performance,network embeddedness patterns
更新于2025-09-23 15:22:29
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Chromatographic Fingerprint Analysis of Radix Hedysari Using Supercritical Fluid Chromatography Coupled with Diode Array Detector
摘要： A newly and rapid supercritical ?uid chromatography method for the simultaneous determination of 11 active compounds in Radix Hedysari samples has been developed and validated. Optimum separation was achieved on a HSS SB C18 column with a gradient elution at a ?ow rate of 1.5 mL/min, back pressure of 11.03 Mpa and diode array detector at 260 nm. The results from the quantitative data showed that contents of these 11 active compounds were different from plant regions. Especially the contents of formononetin in the Minxian county are ～6-fold than in wild Radix Hedysari. The chromatographic ?ngerprint of Radix Hedysari was recorded under the same chromatographic condition. Data analytic procedure was performed to differentiate the 25 batches of Radix Hedysari samples. Data from chromatographic ?ngerprint were also analyzed using hierarchical cluster analysis. The results showed that 23 batches of Radix Hedysari samples had a high similarity (> 0.90) and overall 25 batches of sample were divided into two clusters. Moreover, according to the comparison contents of active compounds in each Radix Hedysari samples, the cultivated location of Radix Hedysari was successfully distinguished. This method presented good stability, repeatability and precision and would be a useful and reliable approach for the quality control of Radix Hedysari. Moreover, all target compounds were quanti?ed by ultra-high performance liquid chromatography–time-of-?ight mass spectrometry.
关键词： Radix Hedysari,supercritical ?uid chromatography,hierarchical cluster analysis,chromatographic ?ngerprint,quality control
更新于2025-09-19 17:13:59
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Protein profiling analysis based on matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry and its application in typing Streptomyces isolates
摘要： Marine Streptomyces is a potential source of novel bioactive natural products in medicine and agriculture. The current discrimination and screening method of Streptomyces isolates is not accurate and time-consuming, and a novel method is necessary. In this study, a protein profiling method based on an ultrahigh resolution 15 Tesla Matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) was established and applied for differentiation and bioactivity screening of marine Streptomyces isolates. To obtain robust protein profiling, the effects of the protein extraction method, the matrix-solvent, the sample deposition mode, and the culture time of isolates on protein profiling were thoroughly studied, the optimal conditions were obtained. To evaluate the performance of the developed MALDI-FTICR MS method, MALDI-time of flight (TOF) MS and 16S rRNA were applied in parallel to analyze 25 marine Streptomyces isolates. We found that the clustering result of MALDI-FTICR MS was more similar to that of 16S rRNA than MALDI-TOF MS. And MALDI-FTICR MS could effectively indicate the antibacterial activity of Streptomyces isolates against three plant pathogenic bacteria including Xanthomonas campestris, Xanthomonas oryzae and Erwinia carotovora. Furthermore, a differential protein/peptide was defined and successfully applied to predict antibacterial activity of blind samples. This study demonstrated that MALDI-FTICR MS has great potential to discriminate and screen complex microorganisms, especially those closely related strains.
关键词： Protein profiling,Streptomyces isolates,Cluster analysis,Activity screening,Matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
更新于2025-09-16 10:30:52
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Quantitative Analysis of Twelve Active Components Combined With Chromatographic Fingerprint for Comprehensive Evaluation of Qinma Prescription by Ultra-Performance Liquid Chromatography Coupled With Diode Array Detection
摘要： A combination method of ultra-performance liquid chromatography (UPLC) coupled with diode array detection has been developed for quality evaluation of Qinma prescription (QMP), based on chromatographic fingerprint technology with the similarity analysis (SA) and the quantitative analysis of 12 components by hierarchical cluster analysis (HCA). The established method has been validated by linearity, precision, repeatability, stability and recovery tests. The UPLC fingerprints with 17 common peaks of 5 QMP samples prepared by different extraction methods including water decoction extraction, water extraction-ethanol precipitation method, ethanol reflux extraction, ethanol extraction-water precipitation method and methanol ultrasonic extraction were obtained, and the SA results indicated that similarity index was greatly influenced by the large peak. The similarity index ranged from 0.816 to 0.999 basing on 17 peaks, which has been decreased to 0.683–0.999 basing on 16 peaks without the large peak of baicalin (BA). The results of simultaneous quantification of 12 components in these 5 QMP samples proved that BA, gallic acid (GA), wogonoside (WOG) and gentiopicroside (GEN) were the major ingredients in QMP with high contents >1.44 (mg/g), indicating that ethanol reflux was the most effective extraction method. Integrating fingerprint analysis, simultaneous determination and HCA, the established method is rapid, sensitive, accurate and readily applicable. All the results indicated that the combination method can control the quality of QMP and its related traditional Chinese medicinal compounds more comprehensively and scientifically.
关键词： quantitative analysis,Qinma prescription,similarity analysis,diode array detection,UPLC,hierarchical cluster analysis,chromatographic fingerprint
更新于2025-09-12 10:27:22
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Heliostat field cleaning scheduling for Solar Power Tower plants: A heuristic approach
摘要： Soiling of heliostat surfaces due to local climate has a direct impact on their optical efficiency and therefore a direct impact on the productivity of the Solar Power Tower plant. Cleaning techniques applied are dependent on plant construction and current schedules are normally developed considering heliostat layout patterns, providing sub-optimal results. In this paper, a method to optimise cleaning schedules is developed, with the objective of maximising energy generated by the plant. First, an algorithm finds a cleaning schedule by solving an integer program, which is then used as a starting solution in an exchange heuristic. Since the optimisation problems are of large size, a p-median type heuristic is performed to reduce the problem dimensionality by clustering heliostats into groups to be cleaned in the same period.
关键词： Solar energy,Routing problems,Cluster analysis,Scheduling
更新于2025-09-10 09:29:36
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Rapid subtyping of pathogenic and nonpathogenic Vibrio parahaemolyticus by fourier transform infrared spectroscopy with chemometric analysis
摘要： Vibrio parahaemolyticus which naturally inhabits marine and estuarine environment represents pathogenic strains (virulence genes tdh or trh positive) and non-pathogenic strains (virulence genes negative). In this study, a rapid method for subtyping pathogenic and non-pathogenic V. parahaemolyticus was established using fourier transform infrared (FTIR) spectroscopy with chemometric analysis. This method targeted three strains of genotypes of V. parahaemolyticus including tdh positive, trh positive and virulence gene-negative (nonpathogenic) V. parahaemolyticus. The FTIR absorption spectra between 1800 and 900 cm?1 highlighted the most distinctive variations and were the most useful for characterizing the three bacteria. The successful differentiation and identification of the three bacteria could be accomplished in less than 1 h by FTIR using principal component analysis (PCA), or another cluster model of hierarchical cluster analysis (HCA). The method was verified by analyzing spiked V. parahaemolyticus fish samples. Furthermore, all of ten clinical isolates of V. parahaemolyticus were identified as tdh-positive, none of the clinical isolates were trh-positive, and all of ten environmental isolates were identified as non-pathogenic by the subtyping method, which were confirmed by PCR assays. All data demonstrated that the newly established subtyping method by FTIR is practical, time-saving, labor-saving, specific and cost-effective, especially suitable for the basic laboratories of CDC and port quarantine departments to perform suiveillance and epidemiological traceability of pathogenic V. parahaemolyticus.
关键词： Pathogenicity,Principal component analysis,Fourier transform infrared spectroscopy,Hierarchical cluster analysis,Vibrio parahaemolyticus,Subtype
更新于2025-09-09 09:28:46
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Potential of Near Infrared Spectroscopy for Classification of Different Delignificant Pre-Treatments on Banana Rachis
摘要： Delignificant pretreatments are fundamental in lignocellulosic materials preprocessing to remove lignin from biomass. Current wet chemical methods are time-consuming, labor-intensive and use hazardous reagents. Near Infrared Spectroscopy (NIRS) provides rapid and non-destructive analysis, and has shown promising results. Spectra collection (8000-4000 cm-1), combined with chemometric analysis based on Cluster Analysis and Principal Component Analysis, has allowed to perform qualitative study of banana rachis, a lignocellulosic residue of agricultural production.
关键词： Near infrared spectroscopy,Cluster analysis,Delignification,Pre-treatments,Banana rachis
更新于2025-09-09 09:28:46
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Discrimination of molecular thin films by surface-sensitive time-resolved optical spectroscopy
摘要： An optical discrimination technique, tailored to nanometric-sized, low optical absorbance molecular complexes adhering to thin metal films, is proposed and demonstrated. It is based on a time-resolved evanescent-wave detection scheme in conjunction with hierarchical cluster analysis and principal value decomposition. The present approach aims to differentiate among molecular films based on statistical methods, without using previous detailed knowledge of the physical mechanisms responsible for the detected signal. The technique is open to integration in lab-on-a-chip architectures and nanoscopy platforms for applications ranging from medical screening to material diagnostics.
关键词： time-resolved optical spectroscopy,principal value decomposition,optical discrimination technique,hierarchical cluster analysis,molecular thin films
更新于2025-09-09 09:28:46