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1.
Over the last decade, the light microscope has become increasingly useful as a quantitative tool for studying colloidal systems. The ability to obtain particle coordinates in bulk samples from micrographs is particularly appealing. In this paper we review and extend methods for optimal image formation of colloidal samples, which is vital for particle coordinates of the highest accuracy, and for extracting the most reliable coordinates from these images. We discuss in depth the accuracy of the coordinates, which is sensitive to the details of the colloidal system and the imaging system. Moreover, this accuracy can vary between particles, particularly in dense systems. We introduce a previously unreported error estimate and use it to develop an iterative method for finding particle coordinates. This individual-particle accuracy assessment also allows comparison between particle locations obtained from different experiments. Though aimed primarily at confocal microscopy studies of colloidal systems, the methods outlined here should transfer readily to many other feature extraction problems, especially where features may overlap one another. 相似文献
2.
Muhammed Ali S. A. Anwar Mustafa Baharuddin Nurul Akidah Somalu Mahendra Rao Muchtar Andanastuti 《Journal of Solid State Electrochemistry》2018,22(1):263-273
Journal of Solid State Electrochemistry - The aim of this work was to investigate the effect of three key fabrication parameters (thickness, solid content, and sintering temperature) on the... 相似文献
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Kelly JG Ahmadzai AA Hermansen P Pitt MA Saidan Z Martin-Hirsch PL Martin FL 《Analytical and bioanalytical chemistry》2011,401(3):957-967
Fine needle aspirates (FNAs) of suspicious breast lesions are often used to aid the diagnosis of female breast cancer. Biospectroscopy
tools facilitate the acquisition of a biochemical cell fingerprint representative of chemical bonds present in a biological
sample. The mid-infrared (IR; 4,000–400 cm−1) is absorbed by the chemical bonds present, allowing one to derive an absorbance spectrum. Complementary to IR spectroscopy,
Raman spectroscopy measures the scattering by chemical bonds following excitation by a laser to generate an intensity spectrum.
Our objective was to apply these methods to determine whether a biospectroscopy approach could objectively segregate different
categories of FNAs. FNAs of breast tissue were collected (n = 48) in a preservative solution and graded into categories by a cytologist as C1 (non-diagnostic), C2 (benign), C3 (suspicious,
probably benign) or C5 (malignant) [or C4 (suspicious, probably malignant); no samples falling within this category were identified
during the collection period of the study]. Following washing, the cellular material was transferred onto BaF2 (IR-transparent) slides for interrogation by Raman or Fourier-transform IR (FTIR) microspectroscopy. In some cases where
sufficient material was obtained, this was transferred to low-E (IR-reflective) glass slides for attenuated total reflection–FTIR
spectroscopy. The spectral datasets produced from these techniques required multivariate analysis for data handling. Principal
component analysis followed by linear discriminant analysis was performed independently on each of the spectral datasets for
only C2, C3 and C5. The resulting scores plots revealed a marked overlap of C2 with C3 and C5, although the latter pair were
both significantly segregated (P < 0.001) in the Raman spectra. Good separation was observed between C3 and C5 in all three spectral datasets. Analysis performed
on the average spectra showed the presence of three distinct cytological groups. Our findings suggest that biospectroscopy
tools coupled with multivariate analysis may support the current FNA tests whilst increasing the sensitivity and associated
reliability for improved diagnostics. 相似文献
5.
I. N. Ivanov 《Journal of Radioanalytical and Nuclear Chemistry》1973,15(2):451-465
Prospects of the application of computers for the selection of optimum methods and for data-processing in activation analysis
are discussed. Programs have been developed to select the irradiation source and the type of recording apparatus and to optimize
time conditions. Various methods for handling gamma-radiation spectra are discussed. Complex utilization of the programs allows
in many cases the elimination of the necessity of developing individual procedures, and the determination of the optimum method
for a given element and given analysis parameter. 相似文献
6.
Cyclic instrumental neutron activation analysis can be used to improve detection limits for short-lived nuclides. The detection limit for a given nuclide is a function of the activity arising from the sample matrix and the various timing parameters used in the analysis. An easily operated computer program, based on the cyclic activation equation, has been developed to estimate theoretically the optimum timing parameters for a number of short-lived nuclides in four different types of simulated sample matrix. The computed results are discussed with reference to the change in maximum sensitivity when optimum conditions are not used, and a comparison is made with the experimentally determined results for the measurement of selenium in NBS Bovine Liver. 相似文献
7.
《Arabian Journal of Chemistry》2021,14(12):103452
We report on the spectral selection of excitation wavelength towards selective detection of aluminum and iron ions using dual emission polymer carbon dots (PCDs). PCDs were prepared from glucose and dilute sulfuric acid using one-pot solvothermal method. The PCDs emit blue light at 480 nm when excited at 340 nm, while emit red light at 590 nm when excited with 400 nm. Spectral selection (selection of excited state) showed sensitivity enhancement for detection of some metal ions. The PCDs showed fluorescence enhancement when combined with Al3+ ions with hypsochromic shift centered at 470 nm when excited at 440 nm. While the PCDs selectively quenched via addition of Fe3+ ions, when excited at 400 nm. The wavelength selection of the same carbon dots increases signal to noise ration. The PCDs showed thermo-sensing behavior from 0 °C to 90 °C with reasonably good reversibility. The PCDs acted as fluorescent probes for multicolor (green and yellow) imaging of MCF-7 cells while not inducing cell death, which indicates that the PCDs are biocompatible and nontoxic to the cells. Therefore, the PCDs can be used as probes for cell-imaging applications in vitro and in vivo. The PCDs proved to be a multi-purpose polymer carbon nanomaterial that can used for pharmaceutical analysis, bio-imaging and thermo-sensing while providing high accuracy, selectivity and a limit of detection in the nano range. 相似文献
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Arash Zulkarnain Ahmad Rozaini Abdullah Abdulhameed Revathy Deivasigamani Nurulhuda Nadzreen Noraziah Mohamad Zin Amin Ahmad Kayani Muhamad Ramdzan Buyong 《Electrophoresis》2023,44(15-16):1220-1233
Characterization of antibiotic-resistant bacteria is a significant concern that persists for the rapid classification and analysis of the bacteria. A technology that utilizes the manipulation of antibiotic-resistant bacteria is key to solving the significant threat of these pathogenic bacteria by rapid characterization profile. Dielectrophoresis (DEP) can differentiate between antibiotic-resistant and susceptible bacteria based on their physical structure and polarization properties. In this work, the DEP response of two Gram-positive bacteria, namely, Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-susceptible S. aureus (MSSA), was investigated and simulated. The DEP characterization was experimentally observed on the bacteria influenced by oxacillin and vancomycin antibiotics. MSSA control without antibiotics has crossover frequencies () from 6 to 8 MHz, whereas MRSA control is from 2 to 3 MHz. The changed when bacteria were exposed to the antibiotic. As for MSSA, the decreased to 3.35 MHz compared to MSSA control without antibiotics, MRSA, increased to 7 MHz when compared to MRSA control. The changes in the DEP response of MSSA and MRSA with and without antibiotics were theoretically proven using MyDEP and COMSOL simulation and experimentally based on the modification to the bacteria cell walls. Thus, the DEP response can be employed as a label-free detectable method to sense and differentiate between resistant and susceptible strains with different antibiotic profiles. The developed method can be implemented on a single platform to analyze and identify bacteria for rapid, scalable, and accurate characterization. 相似文献
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Yang L Arias LR Lane TS Yancey MD Mamouni J 《Analytical and bioanalytical chemistry》2011,399(5):1823-1833
In this study, electrical impedance-based measurements were used to distinguish oral cancer cells and non-cancer oral epithelial
cells based on their cellular activities on the microelectrodes in a real-time and label-free manner. CAL 27 and Het-1A cell
lines were used as the models of oral cancer cells and non-cancer oral epithelial cells, respectively. Various cellular activities,
including cell adhesion, spreading, and proliferation were monitored. We found that both the kinetics of cell spreading and
the static impedance-based cell index were feasible to distinguish the two cell types. At each given cell number, CAL 27 cell
spreading produced a smaller cell index change rate that was 60–70% of those of Het-1A cells. When cells were fully spread,
CAL 27 cells generated a cell index more than four times greater than that of Het-1A cells. Since cell spreading and attachment
occurs in the first few hours when they were cultured on the microelectrodes, this impedance-based method could be a rapid
label-free and non-invasive approach to distinguish oral cancer cells from non-cancer oral epithelial cells. Cell viability
analysis was performed along with the impedance-based analysis. Confocal microscopic imaging analysis showed the difference
in cell morphology and the thickness of cell monolayers between the two cell types. 相似文献
11.
Summary A new equation which describes the interdependence of instrument band spreading, injection volume and input profile is proposed and experimentally verified in two modes: 1. without a column; 2. with a column.It is shown that under equivalent conditions both modes are in excellent agreement. The method of calculation of the variance of a response function appeared to be of utmost importance in correctly interpreting the experimentally observed interdependence of instrumental band spreading and injection characteristics.Presented as part of a poster at the Vth International Symposium on Column Liquid Chromatography, Avignon (France), 11–15 May 1981. 相似文献
12.
New catechol derivatives of safrole and their antiproliferative activity towards breast cancer cells
Madrid Villegas A Espinoza Catalán L Montenegro Venegas I Villena García J Carrasco Altamirano H 《Molecules (Basel, Switzerland)》2011,16(6):4632-4641
Catechols were synthesized from safrole. Nine derivatives were prepared and assessed for antiproliferative effects using different human cell lines. The in vitro growth inhibition assay was based on the sulphorhodamine dye to quantify cell viability. The derivatives 4-allylbenzene-1,2-diol (3), 4 4-[3-(acetyloxy)propyl]-1,2-phenylene diacetate (6) and 4-[3-(acetyloxy)propyl]-5-nitro-1,2-phenylene diacetate (10) showed higher cytotoxicity than the parent compound 2 in tests performed on two breast cancer cell lines (MCF-7 and MDA-MB-231). The IC?? values of 40.2 ± 6.9 μM, 5.9 ± 0.8 μM and 33.8 ± 4.9 μM, respectively, were obtained without toxicity towards dermal human fibroblast (DHF cells). 相似文献
13.
C.V. Ramana Mohabul A. Mondal Vedavati G. Puranik Mukund K. Gurjar 《Tetrahedron letters》2007,48(42):7524-7527
A formal total synthesis of aspercyclide C (3) is described in which d-ribose is employed as a chiral pool material. The key step is a ring closing metathesis. 相似文献
14.
Summary An appropriate procedure based on statistical criteria is suggested for the determination of the optimum set of model parameters
for a given chromatographic system. The criteria employed are the t-ratio test, the rate of change in the sum of squares of
residuals, the standard error of the fit, the F-test, and the CP-test. The suggested procedure has been evaluated using two different models, one based on partition and the other on adsorption
mechanisms, which describe the combined effect of pH and organic modifier content on the retention of ionogenic solutes in
reversed-phase liquid chromatography. It is shown that all the criteria give almost converged results and therefore we may
simply use the F-test, which seems to be the most sensitive and reliable criterion excluding any personal judgement. It is
also found that the retention models tested show a different behavior towards their simplification. In particular, the use
of a reduced equation of the partition model, selected on the basis of the suggested procedure, is necessary for the prediction
of meaningful retention surfaces, whereas the decrease in the number of the adjustable parameters in the adsorption model
offers only noise reduction and fitting simplicity, because no version of this model predicts abnormal retention surfaces. 相似文献
15.
Regnier FE Riggs L Zhang R Xiong L Liu P Chakraborty A Seeley E Sioma C Thompson RA 《Journal of mass spectrometry : JMS》2002,37(2):133-145
Disease, external stimuli (such as drugs and toxins), and mutations cause changes in the rate of protein synthesis, post-translational modification, inter-compartmental transport, and degradation of proteins in living systems. Recognizing and identifying the small number of proteins involved is complicated by the complexity of biological extracts and the fact that post-translational alterations of proteins can occur at many sites in multiple ways. It is shown here that a variety of new tools and methods based on internal standard technology are now being developed to code globally all peptides in control and experimental samples for quantification. The great advantage of these stable isotope-labeling strategies is that mass spectrometers can rapidly target those proteins that have changed in concentration for further analysis. When coupled to stable isotope quantification, targeting can be further focused through chromatographic selection of peptide classes on the basis of specific structural features. Targeting structural features is particularly useful when they are unique to types of regulation or disease. Differential displays of targeted peptides show that stimulus-specific markers are relatively easy to identify and will probably be diagnostically valuable tools. 相似文献
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Metabolomics is an emerging field dealing with the measurement and interpretation of small molecular byproducts of biochemical processes, or metabolites, which can be used to generate profiles from biological samples. Promising for use in pathophysiology, metabolomic profiles give the immediate biological state of a sample. These profiles are altered in diseases and are detectable in biological samples, such as tissue, blood, urine, saliva, and others. Most remarkably, metabolic profiles usually are altered before symptoms appear in a patient. For this reason, metabolomics has potential as a reliable method for an early diagnosis of diseases through disease biomarker identification. This application is most prevalent in cancer, such as head and neck cancer (HNC). Metabolomic studies offer avenues to improve on current medical techniques through the application of mass spectrometry (MS), nuclear magnetic resonance spectroscopy (NMR), and statistical analysis to determine better biomarkers than those currently known. In this review, we discuss the use of MS and NMR tools for detecting biomarkers in tissue and fluid samples, and the appropriateness of metabolomics in analyzing cancer. Advantages, disadvantages, and recent studies on metabolomic profiling techniques in HNC analysis are also discussed herein. 相似文献
18.
Chen J Zhang J Guo Y Li J Fu F Yang HH Chen G 《Chemical communications (Cambridge, England)》2011,47(28):8004-8006
A simple, label-free, ultra-highly sensitive and selective electrochemical sensor based on nuclease-assisted target recycling and DNAzyme for the detection of DNA species related to oral cancer in saliva is developed. 相似文献
19.
Majumder SK Gupta A Gupta S Ghosh N Gupta PK 《Journal of photochemistry and photobiology. B, Biology》2006,85(2):109-117
We report development of a direct multi-class spectroscopic diagnostic algorithm for discrimination of high-grade cancerous tissue sites from low-grade as well as precancerous and normal squamous tissue sites of human oral cavity. The algorithm was developed making use of the recently formulated theory of total principal component regression (TPCR). The in vivo autofluorescence spectral data acquired from patients screened for neoplasm of oral cavity at the Government Cancer Hospital, Indore, was used to train and validate the algorithm. The diagnostic algorithm based on TPCR was found to provide satisfactory performance in classifying the tissue sites in four different classes - high-grade squamous cell carcinoma, low-grade squamous cell carcinoma, leukoplakia, and normal squamous tissue. The classification accuracy for these four classes was observed to be approximately 94%, 100%, 100% and 91% for the training data set (based on leave-one-out cross-validation), and was approximately 90%, 90%, 85% and 88%, respectively for the corresponding classes for the independent validation data set. 相似文献