Reliable 3D detection of diffraction-limited spots in fluorescence microscopy images is an important task in subcellular observation. Generally, fluorescence microscopy images are heavily degraded by noise and non-specifically stained background, making reliable detection a challenging task. In this work, we have studied the performance and parameter sensitivity of eight recent methods for 3D spot detection. The study is based on both 3D synthetic image data and 3D real confocal microscopy images. The synthetic images were generated using a simulator modeling the complete imaging setup, including the optical path as well as the image acquisition process. We studied the detection performance and parameter sensitivity under different noise levels and under the influence of uneven background signal. To evaluate the parameter sensitivity, we propose a novel measure based on the gradient magnitude of the F1 score. We measured the success rate of the individual methods for different types of the image data and found that the type of image degradation is an important factor. Using the F1 score and the newly proposed sensitivity measure, we found that the parameter sensitivity is not necessarily proportional to the success rate of a method. This also provided an explanation why the best performing method for synthetic data was outperformed by other methods when applied to the real microscopy images. On the basis of the results obtained, we conclude with the recommendation of the HDome method for data with relatively low variations in quality, or the Sorokin method for image sets in which the quality varies more. We also provide alternative recommendations for high-quality images, and for situations in which detailed parameter tuning might be deemed expensive.

• Klíčová slova
• 3D imaging, diffraction-limited spot detection, fluorescence microscopy, parameter sensitivity,
• MeSH
• algoritmy MeSH
• fluorescenční mikroskopie metody   MeSH
• konfokální mikroskopie metody   MeSH
• počítačové zpracování obrazu metody   MeSH
• senzitivita a specificita MeSH
• zobrazování trojrozměrné metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

PURPOSE: We aimed to evaluate the diagnostic performance of computed tomography colonography (CTC) in the detection of internal hemorrhoids. METHODS: Three gastroenterologists systematically reported on the presence of internal hemorrhoids in patients with incomplete colonoscopy, for whom they considered a subsequent CTC. For 44 patients with internal hemorrhoids revealed by optical colonoscopy, an age- and gender-matched cohort of 66 patients with normal findings in the rectum was selected. Endoluminal and transaxial CTC views of the rectum were evaluated for the presence of internal hemorrhoids, the anal verge prominence, asymmetry, and cushion-like appearance on a Likert scale by two experienced radiologists and two gastroenterologists. RESULTS: The sensitivity, specificity, and AUC for identification of internal hemorrhoids were 0.61 (95% CI, 0.53-0.68), 0.69 (95% CI, 0.63-0.75) and 0.66 (95% CI, 0.62-0.70), respectively. The radiologists showed a better specificity, the gastroenterologists a slightly better sensitivity. When only the rating "very likely" was considered as positive, the specificity rose to 0.89 (95% CI, 0.81-0.94) with a sensitivity of 0.50 (95% CI, 0.38-0.62). The interobserver agreement was fair. The best predictor of the presence of hemorrhoids was a prominent anal verge in the supine position (OR=1.789, 95% CI, 1.267-2.525). The difference between supine and prone positions in the evaluated features in patients with internal hemorrhoids was not significant. CONCLUSION: CTC has low sensitivity but high specificity in the detection of internal hemorrhoids, if the rater is confident in detecting them. Internal hemorrhoids do not substantially change their shape between prone and supine positions.

• MeSH
• hemoroidy diagnostické zobrazování   MeSH
• kolonografie počítačovou tomografií metody   MeSH
• lidé MeSH
• prospektivní studie MeSH
• rektum diagnostické zobrazování   MeSH
• reprodukovatelnost výsledků MeSH
• senioři MeSH
• senzitivita a specificita MeSH
• sexuální faktory MeSH
• věkové faktory MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

An oligonucleotide microarray for the detection of some fruit-tree viruses was designed and its theoretical detection limit was assessed using Cy3-labelled oligonucleotides. The real sensitivity of the microarray was compared for different kinds of fluorescently labelled targets: (a) cDNA and PCR amplified targets, (b) PCR amplified targets labelled using three different labelling methods. In the first case (a), the number of viral cDNA molecules was below the assessed detection limit of the microarray and only PCR amplified targets were detected. A second comparison (b), done on 3 selected viruses, included indirect labelling, the direct incorporation of labelled-dUTPs, and the use of Cy3-labelled primer. The targets labelled most intensively were produced by the Cy3-primer labelling (2 of 3 viruses) or by the indirect labelling method (1 of 3 viruses), the weakest signal showed targets labelled directly (all 3 viruses). The use of Cy3-primer labelling involved the simplest preparation and the lowest cost, however occasional weak cross-hybridization appeared. The indirect labelling method was of the highest specificity. The probes hybridizing near the 3-end of the targets showed the lowest intensities of fluorescent signal.

• MeSH
• falešně pozitivní reakce MeSH
• fluorescence MeSH
• mikročipová analýza metody   MeSH
• nemoci rostlin virologie   MeSH
• rostlinné viry izolace a purifikace   MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• senzitivita a specificita MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH

Single-cage boron cluster anions with at least 11 cluster atoms, free of bonded functional groups that strongly absorb UV light, and their cobalt complexes have been the investigated compounds. Their UV-absorption spectra have absolute maxima between 200 and 215 nm. Corresponding molar extinction coefficients that are of the order of 10(3)-10(4) L mol(-1) cm(-1) indicate medium detection sensitivity. Its reaching requires elimination of background electrolytes that weaken the UV-light beam in any way. Frequently used carboxylic acids and zwitterionic Good's buffers cannot be used as buffering compounds from this reason. Freshly prepared 1 mM solutions of boron cluster compounds in aqueous sodium chloride, chosen as indifferent electrolyte, which contain 20-30% (v/v) of methanol or acetonitrile, give zones free of tailing. After storing in the fridge, zones of the compounds became pronouncedly tailed even if their solutions remain clear and free of precipitation, turbidity or opalescence. The tailing usually disappeared if the acetonitrile or the methanol concentration in samples was 40-60% (v/v) depending on the dissolved compound hydrophobicity. Solutions of extremely hydrophobic compounds, stored in the fridge, require mild heating to 30-40 degrees C for half an hour for the avoiding of the tailing. Permanent slow decrease in effective mobilites of boron cluster anions was found if background electrolytes contained acetonitrile and beta-cyclodextrin. Analogous decrease was not observed with organic anions. Constant mobilities of boron cluster anions have been reached if acetonitrile was replaced with methanol. Analyte zones were more symmetrical in background electrolytes buffered with sodium borate of pH 9 than in background electrolytes buffered with sodium phosphate of pH 7.

• MeSH
• borany izolace a purifikace   MeSH
• elektroforéza kapilární metody   MeSH
• koncentrace vodíkových iontů MeSH
• pufry MeSH
• senzitivita a specificita MeSH
• spektrofotometrie ultrafialová MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• borany MeSH
• pufry MeSH

A sensitive capillary electrophoretic method featuring spectrophotometric detection using a commercial Z-cell was devised for the assay of 8-hydroxy-2'-deoxyguanosine (8OHdG) in human urine. Solid-phase extraction (SPE) based on hydrophilic-lipophilic-balanced RP sorbent was utilized for urine sample pretreatment and analyte preconcentration. The separation was carried out in conventional fused-silica capillaries employing a Z-cell with hydrodynamic sample injection (at 50 mbar for 12 s). The BGE (pH* 9.2, adjusted with 1 M NaOH) contained 0.15 M boric acid and 10% v/v ACN. The detection wavelength was 282 nm. The calibration curve for 8OHdG (measured in spiked urine) was linear in the range 10-1000 ng/mL; R(2) = 0.9993. The LOD was 3 ng/mL (11 nmol/L) of 8OHdG. Determination of the 8OHdG urinary levels was possible even in healthy individuals.

• Klíčová slova
• 8-Hydroxy-2′-deoxyguanosine, CE, Oxidative stress, Urine,
• MeSH
• 8-hydroxy-2'-deoxyguanosin MeSH
• deoxyguanosin analogy a deriváty   chemie   moč   MeSH
• elektroforéza kapilární metody   MeSH
• extrakce na pevné fázi metody   MeSH
• lidé MeSH
• limita detekce MeSH
• lineární modely MeSH
• reprodukovatelnost výsledků MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 8-hydroxy-2'-deoxyguanosin MeSH
• deoxyguanosin MeSH

Single cell gel electrophoresis, also known as the comet assay, is widely used for the detection and measurement of DNA strand breaks. With the addition of a step in which DNA is incubated with specific endonucleases recognising damaged bases, these lesions can be measured, too. In the standard protocol, electrophoresis is carried out at high pH. If, instead, electrophoresis is in neutral buffer, the effect of DNA damage seems to be much reduced--either because alkaline conditions are needed to reveal certain lesions, or because the effect of the same number of breaks on DNA migration is greater at high pH. A lower sensitivity can be useful in some circumstances, as it extends the range of DNA damage levels over which the assay can be used. Here we compare the performance of standard and modified techniques with a variety of DNA-damaging agents and offer possible explanations for the differences in behaviour of DNA under alternative electrophoretic conditions.

• MeSH
• chinoliziny farmakologie   MeSH
• DNA-formamidopyrimidinglykosylasa MeSH
• elektroforéza v agarovém gelu metody   MeSH
• exodeoxyribonukleasy metabolismus   MeSH
• Fabaceae genetika   MeSH
• HeLa buňky účinky léků   MeSH
• koncentrace vodíkových iontů MeSH
• léčivé rostliny MeSH
• lidé MeSH
• methylmethansulfonát farmakologie   MeSH
• N-glykosylhydrolasy metabolismus   MeSH
• poškození DNA * účinky léků   MeSH
• pufry MeSH
• pyrimidinové dimery analýza   MeSH
• pyrrolidiny farmakologie   MeSH
• senzitivita a specificita MeSH
• vitamin K farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chinoliziny MeSH
• DNA-formamidopyrimidinglykosylasa MeSH
• exodeoxyribonuclease III MeSH Prohlížeč
• exodeoxyribonukleasy MeSH
• methylmethansulfonát MeSH
• N-glykosylhydrolasy MeSH
• pufry MeSH
• pyrimidinové dimery MeSH
• pyrrolidiny MeSH
• Ro 19-8022 MeSH Prohlížeč
• vitamin K MeSH

Ultraviolet (UV) sensors are a key component in growing applications such as water quality treatment and environmental monitoring, with considerable interest in their miniaturization and enhanced operation. This work presents a passive gold coplanar waveguide split ring resonator integrated with anodic self-organized TiO2 nanotube (TNT) membranes with a thickness of 20 μm to provide real-time UV detection. The resonator operated as a one-port device to capture the reflection coefficient (S11) signal, with a center frequency of 16 GHz and a notch amplitude of -88 dB. It was experimentally analyzed for its UV sensing capability in the range of 36.5-463 μW/cm2. The high-frequency resonator was improved through design choices including the addition of a tapered input transmission line, wire bonding for practical device design, and an interdigitated capacitive ring gap. The high frequency also helped mitigate noise due to water vapor or environmental contaminants. S11 amplitude variation was found through both experiments and modeling to follow a linear trend with UV illumination intensity. The resonator exhibited over 45 ± 2 dB shift in the resonant amplitude under the highest UV illumination conditions, with a sensitivity of 0.084 dB/μW cm-2 and the potential to sense UV intensity as low as 2.7 μW/cm2. The presented device enabled a repeatable and accurate microwave response under UV illumination with very high sensitivity, entirely through the use of passive circuit elements.

• Klíčová slova
• TiO2 nanotube membrane, UV detection, coplanar waveguide resonator, real-time microwave sensing, split ring resonator,
• Publikační typ
• časopisecké články MeSH

We carried out a calibration of FLOTAC for ciliates Troglodytella abrassarti and Neobalantidium coli based on the selection of a most appropriate flotation solutions, and we also tested its accuracy (i.e., number of detected stages out of known added number of stages to fecal samples) and sensitivity for trophozoites of both ciliates in chimpanzee feces and N. coli cysts in pig feces, compared the detection threshold of FLOTAC with MIF-based sedimentation, and, subsequently, tested the losses of ciliate stages during sample preparation. Nine flotation solutions were evaluated, and ZnSO4 solution (specific gravity [s.g.] 1.2) showed to be the most suitable for trophozoite detection, while Sheather's solution (s.g. 1.33) was selected as most suitable for cysts. The FLOTAC sensitivity in detection of both stages varied: for trophozoites, we found all samples were positive when the intensity of infection 10 trophozoites per gram and higher, whereas for cysts the sensitivity was lower. The accuracy of FLOTAC negatively correlated with infection intensity, and the merthiolate-iodine-formaldehyde sedimentation-based quantification had a lower detection threshold. We demonstrated additional losses of stages of T. abrassarti and N. coli due to their retention in the sediment, which is probably a major reason for discrepancies in the numbers of countable ciliates between both methods. In conclusion, the FLOTAC should not be considered as a gold standard for quantification of intestinal ciliates in primates; instead, we recommend the modified MIF method.

• MeSH
• Ciliophora izolace a purifikace   MeSH
• feces parazitologie   MeSH
• infekce prvoky kmene Ciliophora diagnóza   parazitologie   veterinární   MeSH
• kalibrace MeSH
• limita detekce MeSH
• nemoci lidoopů diagnóza   parazitologie   MeSH
• nemoci prasat diagnóza   parazitologie   MeSH
• Pan troglodytes parazitologie   MeSH
• prasata MeSH
• roztoky chemie   klasifikace   MeSH
• senzitivita a specificita MeSH
• specifická hustota MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• validační studie MeSH
• Názvy látek
• roztoky MeSH

The new screening method for rapid evaluation of major phenolic compounds in apples has been developed. Suitability of coupling HPLC/UHPLC separation with the diode-array detection and universal charged aerosol detection with respect to the presence of interfering substances was tested. Characteristics of both detection techniques were compared and method linearity, limits of detection and quantitation, and selectivity of them determined. Student t-test based on slopes of calibration plots was applied for the detailed comparison. The diode-array detection provided the best results regarding sensitivity and selectivity of the developed method in terms of evaluation of phenolics profiles. The response of the charged aerosol detector was negatively affected by co-eluting substances during rapid-screening analyses. Coulometric detection was used for advanced characterization of extracts in terms of antioxidant content and strength to obtain more complex information concerning sample composition. This detection also allowed evaluation of unidentified compounds with antioxidant activity. HPLC/UHPLC separation using a combination of diode-array and coulometric detectors thus represented the best approach enabling quick, yet complex characterization of bioactive compounds in apples.

• Klíčová slova
• antioxidants, apple extracts, charged aerosol detection, complex matrices, coulometric detection, detection sensitivity, diode-array detection, phenolic compounds,
• MeSH
• aerosoly chemie   MeSH
• antioxidancia chemie   MeSH
• chromatografie metody   MeSH
• elektrochemie metody   MeSH
• fenol chemie   MeSH
• fenoly analýza   MeSH
• kalibrace MeSH
• limita detekce MeSH
• Malus metabolismus   MeSH
• potravinářská technologie MeSH
• reprodukovatelnost výsledků MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aerosoly MeSH
• antioxidancia MeSH
• fenol MeSH
• fenoly MeSH

Separation technologies play an important role in revealing biological processes at various omic levels, in pharmacological and clinical research. In this context, CE is a strong candidate for analyses of samples with rapidly increasing complexity. Even though CE is well known for its many advantages in this regard, the sensitivity of CE analyses is insufficient for many applications. Accordingly, there are generally three main options for enhancing the sensitivity of CE analyses - using special detection techniques, using sample pre-concentration and derivatisation. Derivatisation is often the method of choice for many laboratories, since it is simple and provides several advantages such as small sample volume demand and the possibility of automation. Although it can be performed in different ways depending on where the reaction takes place, this article reviews one of the simplest and at the same time most useful approaches on-capillary derivatisation. Even if in many cases the use of on-capillary derivatisation alone is enough to improve the detection sensitivity, on other occasions it needs to be employed in combination with the other above-mentioned strategies. After a simple discussion of derivatisation in general, special attention is focused on the on-capillary approach and methodologies available for on-capillary reactant mixing. Its applications in various fields are also described.

• Klíčová slova
• Capillary electrophoresis, Derivatisation, Enhancing of sensitivity, On-capillary derivatisation,
• MeSH
• aminokyseliny analýza   MeSH
• elektroforéza kapilární metody   MeSH
• elektrolyty chemie   MeSH
• peptidy analýza   MeSH
• sacharidy analýza   MeSH
• senzitivita a specificita MeSH
• sulfhydrylové sloučeniny analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• aminokyseliny MeSH
• elektrolyty MeSH
• peptidy MeSH
• sacharidy MeSH
• sulfhydrylové sloučeniny MeSH