A colorimetric RT-LAMP assay and LAMP-sequencing for detecting SARS-CoV-2 RNA in clinical samples.

The coronavirus disease 2019 (COVID-19) pandemic caused by the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) coronavirus is a major public health challenge. Rapid tests for detecting existing SARS-CoV-2 infections and assessing virus spread are critical. Approaches to detect viral RNA based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) have potential as simple, scalable, and broadly applicable testing methods. Compared to RT quantitative polymerase chain reaction (RT-qPCR)-based methods, RT-LAMP assays require incubation at a constant temperature, thus eliminating the need for sophisticated instrumentation. Here, we tested a two-color RT-LAMP assay protocol for detecting SARS-CoV-2 viral RNA using a primer set specific for the N gene. We tested our RT-LAMP assay on surplus RNA samples isolated from 768 pharyngeal swab specimens collected from individuals being tested for COVID-19. We determined the sensitivity and specificity of the RT-LAMP assay for detecting SARS-CoV-2 viral RNA. Compared to an RT-qPCR assay using a sensitive primer set, we found that the RT-LAMP assay reliably detected SARS-CoV-2 RNA with an RT-qPCR cycle threshold (CT) number of up to 30, with a sensitivity of 97.5% and a specificity of 99.7%. We also developed a swab-to-RT-LAMP assay that did not require a prior RNA isolation step, which retained excellent specificity (99.5%) but showed lower sensitivity (86% for CT < 30) than the RT-LAMP assay. In addition, we developed a multiplexed sequencing protocol (LAMP-sequencing) as a diagnostic validation procedure to detect and record the outcome of RT-LAMP reactions.

A colorimetric sensor array for the discrimination of glucosinolates.

A novel approach for the discrimination of different glucosinolates (sinigrin, progoitrin, gluconapin, 4-methoxyglucobrassicin, glucoraphanin, glucobrassicin, glucoiberin, glucobrassicanapin, glucoraphenin, and glucoerucin) using a colorimetric sensor array (CSA) is reported herein. The developed CSA technique exhibited an acceptable linearity (r2 ≥ 0.97) over a concentration range of 0-150 µM for the 10 glucosinolates. The CSA coupled with principal component analysis and hierarchical cluster analysis correctly distinguished the majority of glucosinolate samples according to their type. In addition, the CSA coupled with linear discriminant analysis correctly classified the majority of 8 kinds of cruciferous vegetable samples with an overall accuracy of 94%. Furthermore, the partial least squares regression results showed that the CSA responses were correlated with the concentration in a correlation coefficient (Rp) range of 0.813-0.964. These results demonstrate that the described procedure based on the CSA technique could be useful for the rapid discrimination of different glucosinolates.

Quantum dot (QD)-based probes for multiplexed determination of heavy metal ions.

Heavy metal contamination is a major global concern and additive toxicity resulting from the exposure to multiple heavy metal ions is more pronounced than that induced by a single metal species. Quantum dots (QDs) have demonstrated unique properties as sensing materials for heavy metal ions over the past two decades. With the rapid development and deep understanding on determination of single heavy metal ion using QD probes, this technology has been employed for sensing multiple metal ions. This review (with 97 refs.) summarizes the progress made in recent years in methods for multiplexed determination of heavy metal ions using QDs. Following an introduction into the importance of simultaneous quantitation of multiple heavy metal ions in environmentally relevant settings, the review discusses the applications of different types of QDs, i.e. chalcogenide, carbon, polymer and graphene in this field. Determination strategies based on fluorometric, colorimetric and electrochemical responses were reviewed including the testing mechanisms and differentiation between various metal ions. In addition, current state of the art sensor constructions, i.e. immobilization of QDs on solid substrate and sensor arrays have been highlighted. A concluding section describes the limitations, opportunities and future challenges of the QD probes. We also compiled a comprehensive table of currently available literature. The listed papers provided information in the following categories, i.e. type of QDs used, ligands or other components in the probe, metal ions tested, medium/substrate of the probe, transduction methods, discrimination mechanism, limit of detection (LOD) and concentration range. Graphic abstract.

Quantification of Colorimetric Data for Paper-Based Analytical Devices.

Colorimetric measurements by image analysis, giving RGB or HSV data, have become commonplace with optical indicator-based assays and as a readout for paper-based analytical devices (PADs). Yet, most works on PADs tend to ignore the quantitative relationship between color data and concentration, which may hamper their establishment as analytical devices and make it difficult to properly understand chemical or biological reactions on the paper substrate. This Perspective Article discusses how image color data are computed into colorimetric absorbance values that correlate linearly to dye concentration and compare well to traditional spectrophotometry. Thioflavin T (ThT), Neutral Red (NR), and Orange IV are used here as model systems. Absorbance measurements in solution correlate well to image data (and Beer's law) from the color channel of relevance if the gamma correction normally used to render the picture more natural to the human eye is removed. This approach also allows one to correct for color cast and variable background color, which may otherwise limit quantitation in field measurements. Reflectance measurements on paper color spots are equally found to correlate quantitatively between spectroscopy and imaging devices. In this way, deviations from Beer's law are identified that are explained with dye interactions on the paper substrate.

Color density spectral array for early evaluation of prognosis of patients with coma in pediatric intensive care unit.

The aim of this study was to assess the bedside brain function monitoring of color density spectral array (CDSA) for early prognostic evaluation of coma patients in pediatric intensive care unit (PICU).Forty-two consecutive pediatric coma patients were enrolled. The individual conscious state was evaluated according to the Glasgow coma scale (GCS). CDSA parameters including CDSA pattern (CDSAP), sleep-wake cycle (SWC), sleep stage (SS), and drug-induced fast wave activity (DIFWA) were recorded. Three months later, prognosis was evaluated according to pediatric cerebral performance category (PCPC) score, based on which the patients were divided into FP-group (favorable prognosis) and PP-group (poor prognosis).The changeable type of CDSAP, appearance of SWC, SS, and DIFWA were significantly correlated with favorable prognosis. Both GCS and SWC were significantly correlated with the prognosis. However, there was substantial overlap in GCS between FP-group and PP-group. Although the absence of SWC was statistically an independent risk factor for poor prognosis but with a high false positive rate (0.143), a linear logistic regression showed the odds ratio of GCS for predicting prognosis was 0.93 (95% confidence interval: 0.48-1.80; P = .83) and that of SWC was 0.12 (95% confidence interval: 0.03-0.47; P = .03). Furthermore, the absence of SWC was correlated with poor prognosis in nonintracranial infection patients.Our study found that several CDSA factors are associated with prognosis of coma patients in PICU. SWC may be a potential indicator for evaluating the prognosis of coma patients in PICU.

Signature maps for automatic identification of prostate cancer from colorimetric analysis of H&E- and IHC-stained histopathological specimens.

Prostate cancer (PCa) is a major cause of cancer death among men. The histopathological examination of post-surgical prostate specimens and manual annotation of PCa not only allow for detailed assessment of disease characteristics and extent, but also supply the ground truth for developing of computer-aided diagnosis (CAD) systems for PCa detection before definitive treatment. As manual cancer annotation is tedious and subjective, there have been a number of publications describing methods for automating the procedure via the analysis of digitized whole-slide images (WSIs). However, these studies have focused only on the analysis of WSIs stained with hematoxylin and eosin (H&E), even though there is additional information that could be obtained from immunohistochemical (IHC) staining. In this work, we propose a framework for automating the annotation of PCa that is based on automated colorimetric analysis of both H&E and IHC WSIs stained with a triple-antibody cocktail against high-molecular weight cytokeratin (HMWCK), p63, and α-methylacyl CoA racemase (AMACR). The analysis outputs were then used to train a regression model to estimate the distribution of cancerous epithelium within slides. The approach yielded an AUC of 0.951, sensitivity of 87.1%, and specificity of 90.7% as compared to slide-level annotations, and generalized well to cancers of all grades.

A rapid and sensitive colorimetric assay for the determination of adenosine kinase activity.

Adenosine kinase (ADK) plays an important role in the growth and development of organisms. A convenient, quick, reliable, sensitive and low-cost assay for ADK activity is of great significance. Here, we found the reaction system with bromothymol blue as the pH indicator had a maximum absorption peak at 614 nm. The absorbance change in 614 nm was positively correlated with the generated hydrogen ions in the reaction catalyzed by ADK. Then, we demonstrated this assay was feasible for ADK activity. Further, we analyzed the effects of buffer, bromothymol blue concentrations on the sensitivity of the assay, and investigated the sensitivity of ADK contents and adenosine concentration on the assay. Finally, we calculated the Km and Vmax of ADK from Bombyx mori with this assay. Our results suggested this assay was quick, convenient, reliable, sensitive and economic for the activity of ADK. It is an excellent alternative for the conventional ADK assays.

End-Tidal Carbon Dioxide Use for Tracheal Intubation: Analysis From the National Emergency Airway Registry for Children (NEAR4KIDS) Registry.

OBJECTIVE: Waveform capnography use has been incorporated into guidelines for the confirmation of tracheal intubation. We aim to describe the trend in waveform capnography use in emergency departments and PICUs and assess the association between waveform capnography use and adverse tracheal intubation-associated events. DESIGN: A multicenter retrospective cohort study. SETTING: Thirty-four hospitals (34 ICUs and nine emergency departments) in the National Emergency Airway Registry for Children quality improvement initiative. PATIENTS: Primary tracheal intubation in children younger than 18 years. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patient, provider, and practice data for tracheal intubation procedure including a type of end-tidal carbon dioxide measurement, as well as the procedural safety outcomes, were prospectively collected. The use of waveform capnography versus colorimetry was evaluated in association with esophageal intubation with delayed recognition, cardiac arrest, and oxygen desaturation less than 80%. During January 2011 and December 2015, 9,639 tracheal intubations were reported. Waveform capnography use increased over time (39% in 2010 to 53% in 2015; p < 0.001), whereas colorimetry use decreased (< 0.001). There was significant variability in waveform capnography use across institutions (median 49%; interquartile range, 25-85%; p < 0.001). Capnography was used more often in emergency departments as compared with ICUs (66% vs. 49%; p < 0.001). The rate of esophageal intubation with delayed recognition was similar with waveform capnography versus colorimetry (0.39% vs. 0.46%; p = 0.62). The rate of cardiac arrest was also similar (p = 0.49). Oxygen desaturation occurred less frequently when capnography was used (17% vs. 19%; p = 0.03); however, this was not significant after adjusting for patient and provider characteristics. CONCLUSIONS: Significant variations existed in capnography use across institutions, with the use increasing over time in both emergency departments and ICUs. The use of capnography during intubation was not associated with esophageal intubation with delayed recognition or the occurrence of cardiac arrest.

Post-standardization of routine creatinine assays: are they suitable for clinical applications.

Introduction Reliable serum creatinine measurements are of vital importance for the correct classification of chronic kidney disease and early identification of kidney injury. The National Kidney Disease Education Programme working group and other groups have defined clinically acceptable analytical limits for creatinine methods. The aim of this study was to re-evaluate the performance of routine creatinine methods in the light of these defined limits so as to assess their suitability for clinical practice. Method In collaboration with the Dutch External Quality Assurance scheme, six frozen commutable samples, with a creatinine concentration ranging from 80 to 239 µmol/L and traceable to isotope dilution mass spectrometry, were circulated to 91 laboratories in four European countries for creatinine measurement and estimated glomerular filtration rate calculation. Two out of the six samples were spiked with glucose to give high and low final concentrations of glucose. Results Results from 89 laboratories were analysed for bias, imprecision (%CV) for each creatinine assay and total error for estimated glomerular filtration rate. The participating laboratories used analytical instruments from four manufacturers; Abbott, Beckman, Roche and Siemens. All enzymatic methods in this study complied with the National Kidney Disease Education Programme working group recommended limits of bias of 5% above a creatinine concentration of 100 µmol/L. They also did not show any evidence of interference from glucose. In addition, they also showed compliance with the clinically recommended %CV of ≤4% across the analytical range. In contrast, the Jaffe methods showed variable performance with regard to the interference of glucose and unsatisfactory bias and precision. Conclusion Jaffe-based creatinine methods still exhibit considerable analytical variability in terms of bias, imprecision and lack of specificity, and this variability brings into question their clinical utility. We believe that clinical laboratories and manufacturers should work together to phase out the use of relatively non-specific Jaffe methods and replace them with more specific methods that are enzyme based.

Evaluation of reliability and validity of three dental color-matching devices.

PURPOSE: To assess the repeatability and accuracy of three dental color-matching devices under standardized and freehand measurement conditions. MATERIALS AND METHODS: Two shade guides (Vita Classical A1-D4, Vita; and Vita Toothguide 3D-Master, Vita), and three color-matching devices (Easyshade, Vita; SpectroShade, MHT Optic Research; and ShadeVision, X-Rite) were used. Five shade tabs were selected from the Vita Classical A1-D4 (A2, A3.5, B1, C4, D3), and five from the Vita Toothguide 3D-Master (1M1, 2R1.5, 3M2, 4L2.5, 5M3) shade guides. Each shade tab was recorded 15 continuous, repeated times with each device under two different measurement conditions (standardized, and freehand). Both qualitative (color shade) and quantitative (L, a, and b) color characteristics were recorded. The color difference (ΔE) of each recorded value with the known values of the shade tab was calculated. The repeatability of each device was evaluated by the coefficient of variance. The accuracy of each device was determined by comparing the recorded values with the known values of the reference shade tab (one sample t test; α = 0.05). The agreement between the recorded shade and the reference shade tab was calculated. The influence of the parameters (devices and conditions) on the parameter ΔE was investigated (two-way ANOVA). Comparison of the devices was performed with Bonferroni pairwise post-hoc analysis. RESULTS: Under standardized conditions, repeatability of all three devices was very good, except for ShadeVision with Vita Classical A1-D4. Accuracy ranged from good to fair, depending on the device and the shade guide. Under freehand conditions, repeatability and accuracy for Easyshade and ShadeVision were negatively influenced, but not for SpectroShade, regardless of the shade guide. CONCLUSION: Based on the total of the color parameters assessed per device, SpectroShade was the most reliable of the three color-matching devices studied.

Structural color changes in permanent enamel of patients with cleft lip and palate: a case-control study.

OBJECTIVES: White spots are more common in patients with cleft lip and palate (CLP) than in the normal population. Whether these are due to the cleft itself or concomitant circumstances (e.g., surgical procedures, orthodontic treatments, systemic fluoridation, increased caries risk) remains unclear. This case-control study evaluated both their prevalence in CLP patients versus control subjects and associated risk factors. PATIENTS AND METHODS: A total of 73 CLP patients (average age 8.7 years, range 6-18 years, 42 % male) and a control group of 73 age- and gender-matched non-CLP patients were included. Enamel color changes, subsuming mineralization defects (DDE index), mild dental fluorosis (Dean's index), and initial caries (ICDAS score 2), were recorded. Caries index (dmf-t/DMF-T) scores were also recorded to distinguish between high or low caries risk as defined by the Deutsche Arbeitsgemeinschaft für Jugendzahnpflege criteria. Histories of systemic fluoridation, trauma to primary teeth, surgery, and orthodontic treatment were obtained using a questionnaire. Statistical analysis included t test, χ (2) test, and multivariable logistic regression. RESULTS: Enamel color changes were observed three times more often in the CLP group than in the control group (39.7 vs. 12.3 %; p < 0.001). Significantly more patients in the CLP group had a history of orthodontic treatment (38.4 vs. 15.1 %; p < 0.05). An increased risk for enamel color changes was associated with CLP itself [OR (odds ratio) 3.6; 95 % confidence interval (CI) 1.3-9.9] and table salt plus tablets combined for systemic fluoridation (OR 2.7, 95 % CI 1.1-6.9). No increased risks were identified for increased caries risk, history of primary-tooth trauma, or history of orthodontic treatment. CONCLUSION: The higher prevalence of enamel color changes in the CLP group (more than threefold compared to the control group) was not related to previous orthodontic treatments; however, systemic fluoridation (table salt and tablets) constituted a risk factor for the enamel color changes seen in the CLP patients.

Effect of two fluoride varnishes on the color stability of three resin-based restorative materials: an in vitro study.

AIM: The aim of the present study was to evaluate the effect of two fluoride varnishes on color stability of three resin-based restorative materials. METHODS: Fifty-four discs (14.5 × 1.7 mm) were fabricated from A2 and A3 shades of a compomer (F2000), a flowable composite (Z350), and a hybrid composite (Z250), and incubated at 37°C for 48 h. Dura Shield (colored) and Fluor Protector (colorless) fluoride varnishes were applied onto the discs. The coating was cleaned using a low-speed handpiece and nylon bristle brush after 24 h of storage in distilled water. A second coating was then applied. A control group with no coating was immersed in distilled water and used. The CIE L*a*b* color scale was measured before the treatments and following each cleaning utilizing a spectrophotometer. RESULTS: The colored fluoride varnish exhibited the highest overall color change (∆E) after the first and the second cleaning procedures in all the materials. Among these, the greatest color change was observed in the A3 shade of F2000, followed by the A3 shade of Z-250. The ∆E was less than 3.3 in all groups, and was therefore clinically acceptable. CONCLUSION: Color changes following the application of fluoride varnishes were found to be clinically acceptable in all groups.

Highly sensitive and specific colorimetric detection of cancer cells via dual-aptamer target binding strategy.

Simple, rapid, sensitive and specific detection of cancer cells is of great importance for early and accurate cancer diagnostics and therapy. By coupling nanotechnology and dual-aptamer target binding strategies, we developed a colorimetric assay for visually detecting cancer cells with high sensitivity and specificity. The nanotechnology including high catalytic activity of PtAuNP and magnetic separation & concentration plays a vital role on the signal amplification and improvement of detection sensitivity. The color change caused by small amount of target cancer cells (10 cells/mL) can be clearly distinguished by naked eyes. The dual-aptamer target binding strategy guarantees the detection specificity that large amount of non-cancer cells and different cancer cells (10(4) cells/mL) cannot cause obvious color change. A detection limit as low as 10 cells/mL with detection linear range from 10 to 10(5) cells/mL was reached according to the experimental detections in phosphate buffer solution as well as serum sample. The developed enzyme-free and cost effective colorimetric assay is simple and no need of instrument while still provides excellent sensitivity, specificity and repeatability, having potential application on point-of-care cancer diagnosis.

Out-of-hospital pediatric airway management in the United States.

OBJECTIVE: The objective of this study was to characterize pediatric out-of-hospital airway management interventions, success rates, and complications in the United States using the 2012 National Emergency Medical Services Information System (NEMSIS) dataset. METHODS: In 2012, NEMSIS collected data from Emergency Medical Services (EMS) encounters in 40 states. We included all patients less than 18 years of age and identified all patients who had airway interventions including endotracheal intubation (ETI), bag-valve-mask ventilation (BVM), continuous positive airway pressure/bilevel positive airway pressure (CPAP/BiPAP) and alternate airways (Combitube, King LT, Laryngeal Mask Airway (LMA), esophageal obturator airway, and cricothyroidotomy). Success and complication rates were analyzed and compared across pediatric age groups, by race, ethnicity, clinical condition, and geographic region. RESULTS: We identified a total of 949,301 pediatric patient care events in the NEMSIS 2012 dataset. 4.5% had airway management procedures (42,936 events). Invasive airway management or ventilation (ETI, cricothyroidotomy, alternate airway, CPAP/BiPAP, BVM and other ventilation) took place in 1.5% of patient care events (14,107). Of those who had invasive airway management, 29.9% were less than 1 year of age, 58.1% were male, 42.3% were white, and 83.6% were in urban areas. ETI occurred in 3124 of patient care events (329 per 100,000; 95% CI 318-341). Overall success of ETI was 81.1% (95% CI 79.7-82.6). Lower success was noted in patients with cardiac arrest (75.5%, 95% CI 72.6-78.3) and those aged 1-12 months (72.1%, 95% CI 68.3-75.6). CONCLUSIONS: Out-of-hospital pediatric advanced airway procedures were infrequently performed. Success rates are lowest in patients aged 1-12 months.

Saliva urea nitrogen dipstick - a novel bedside diagnostic tool for acute kidney injury.

BACKGROUND AND AIMS: Measurement of saliva urea nitrogen (SUN) may be valuable in the screening of kidney failure. Here we evaluate the diagnostic performance of SUN dipsticks in patients with acute kidney injury (AKI). MATERIAL AND METHODS: We measured SUN and blood urea nitrogen (BUN) in hospitalized patients diagnosed with AKI based on Acute Kidney Injury Network (AKIN)-criteria. After collection, saliva was transferred to a colorimetric SUN dipstick. We then compared the resultant test-pad color to six standardized color fields indicating SUN of 5 - 14 (#1), 15 - 24 (#2), 25 - 34 (#3), 35 - 54 (#4), 55 - 74 (#5), and ≥ 75 (#6) mg/dL, respectively. We assessed the performance of SUN and BUN to discriminate AKIN 3 from earlier stages by the area under receiver operating characteristic curves (AUC ROC). RESULTS: We enrolled 44 patients (59.5 ± 18 years, 58% female; pre-renal AKI: 67%; renal 24%; post-renal 9%) in AKIN stages 1 (59%), 2 (16%), and 3 (25%). SUN and BUN levels were correlated (Spearman rank Rs = 0.69; p < 0.001, n = 44) with the highest correlation in AKIN 1 (Rs = 0.63, p = 0.001, n = 26). SUN allowed a significant discrimination of AKIN 3 from earlier stages (AUC ROC 0.91; 95% CI 0.80 - 1.0), which was comparable to the diagnostic performance of BUN (AUC ROC 0.90; 95% CI 0.78 - 1.0). CONCLUSIONS: SUN dipsticks allow the discrimination of AKIN 3 from earlier AKI stages. This low-technology approach may aid the screening of severe AKI in areas where laboratory resources are scarce.

Reliability and validity of a quantitative color scale to evaluate masticatory performance using color-changeable chewing gum.

In the present study, we developed a novel color scale for visual assessment, conforming to theoretical color changes of a gum, to evaluate masticatoryperformance; moreover, we investigated the reliability and validity of this evaluation method using the color scale. Ten participants (aged 26.30 years) with natural dentition chewed the gum at several chewing strokes. Changes in color were measured using a colorimeter, and then, linearregression expressions that represented changes in gum color were derived. The color scale was developed using these regression expressions. Thirty-two chewed gums were evaluated using colorimeter and were assessed three times using the color scale by six dentists aged 25.27 (mean, 25.8) years, six preclinical dental students aged 21.23 (mean, 22.2) years, and six elderly individuals aged 68.84 (mean, 74.0) years. The intrarater and interrater reliability of evaluations was assessed using intraclass correlation coefficients. Validity of the method compared with a colorimeter was assessed using Spearman's rank correlation coefficient. All intraclass correlation coefficients were > 0.90, and Spearman's rank-correlation coefficients were > 0.95 in all groups. These results indicated that the evaluation method of the color-changeable chewing gum using the newly developed color scale is reliable and valid.

Intra- and inter-rater reliability of digital image analysis for skin color measurement.

BACKGROUND: We determined the intra- and inter-rater reliability of data from digital image color analysis between an expert and novice analyst. METHODS: Following training, the expert and novice independently analyzed 210 randomly ordered images. Both analysts used Adobe(®) Photoshop lasso or color sampler tools based on the type of image file. After color correction with Pictocolor(®) in camera software, they recorded L*a*b* (L*=light/dark; a*=red/green; b*=yellow/blue) color values for all skin sites. We computed intra-rater and inter-rater agreement within anatomical region, color value (L*, a*, b*), and technique (lasso, color sampler) using a series of one-way intra-class correlation coefficients (ICCs). RESULTS: Results of ICCs for intra-rater agreement showed high levels of internal consistency reliability within each rater for the lasso technique (ICC ≥ 0.99) and somewhat lower, yet acceptable, level of agreement for the color sampler technique (ICC = 0.91 for expert, ICC = 0.81 for novice). Skin L*, skin b*, and labia L* values reached the highest level of agreement (ICC ≥ 0.92) and skin a*, labia b*, and vaginal wall b* were the lowest (ICC ≥ 0.64). CONCLUSION: Data from novice analysts can achieve high levels of agreement with data from expert analysts with training and the use of a detailed, standard protocol.

Clinical application of a digital method to improve the accuracy of color perception in toluidine blue stained oral mucosal lesions.

OBJECTIVE: Color perception is an important variable in detecting and assessing oral conditions. The aim was to investigate clinicians' perception of toluidine blue (Tblue) staining compared to digital color analysis, which may impact mucosal lesion detection, affect the decision to biopsy, and biopsy site selection. METHOD AND MATERIALS: Four oral lesions were stained with Tblue. Digital color analyses of eight areas on each image were completed and were considered as "gold standard" (GS). Twenty specialists ranked these areas according to their perceived intensity of blue stain in two sessions. RESULTS: Consistency between GS and observers rankings was 0.8791. However, more than half of the observers inaccurately perceived the intermediate blue tones. Overall interobserver agreement was 0.8714; stability between two sessions decreased to 45% for intermediate tones. CONCLUSION: Assessing the equivocal blueness of an oral mucosal lesion in clinical settings may vary due to variation in visual perception. A digital method for objective color analysis in clinical practice may be used to eliminate this deficiency by implementing a mathematical formula.

Sensitive colorimetric visualization of dihydronicotinamide adenine dinucleotide based on anti-aggregation of gold nanoparticles via boronic acid-diol binding.

A facile, highly sensitive colorimetric strategy for dihydronicotinamide adenine dinucleotide (NADH) detection is proposed based on anti-aggregation of gold nanoparticles (AuNPs) via boronic acid-diol binding chemistry. The aggregation agent, 4-mercaptophenylboronic acid (MPBA), has specific affinity for AuNPs through Au-S interaction, leading to the aggregation of AuNPs by self-dehydration condensation at a certain concentration, which is responsible for a visible color change of AuNPs from wine red to blue. With the addition of NADH, MPBA would prefer reacting with NADH to form stable borate ester via boronic acid-diol binding dependent on the pH and solvent, revealing an obvious color change from blue to red with increasing the concentration of NADH. The anti-aggregation effect of NADH on AuNPs was seen by the naked eye and monitored by UV-vis extinction spectra. The linear range of the colorimetric sensor for NADH is from 8.0 × 10(-9)M to 8.0 × 10(-6)M, with a low detection limit of 2.0 nM. The as-established colorimetric strategy opened a new avenue for NADH determination.

A comparison between laser-doppler imaging and colorimetry in the assessment of scarring: "a pilot study".

BACKGROUND: This cross-sectional pilot-study investigated the reproducibility of the LDI (Moor-LDI-B2; Moor Instruments) and the chromameter (Minolta chromameter CR-300) when used in scar assessment. METHODS: Twenty-seven scars in 14 subjects were included between January and June 2003. One observer performed two times both measurements with 10 min apart. The intra-observer agreement is quantified by means of the intra-class correlations (ICC) and the standard errors of measurement (SEM) for both the LDI and the chromameter. RESULTS: Ignoring one outlier, the ICC of the LDI = 0.856 and the SEM = 34.56. The chromameter shows a better reproducibility with an ICC of 0.93 and a SEM of 0.79. CONCLUSION: This pilot-study with a limited number of measurements shows a moderate reproducibility of the LDI compared to the chromameter measurements, in the assessment of respectively flux and redness in scars.