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The value of three-dimensional virtual objects are proven in a great variety of applications; their flexibility allowing for a substantial amount of utilization purposes. In cultural heritage this has been used for many years already, and the amount of users continue to grow as acquisition methods and implementations are becoming more approachable. Nonetheless, there are still many apparent issues with making use of all the possible benefits of 3D data in the field, varying from lack of knowledge, infrastructure, or coherent workflows. This review aims to underline the current limitations in implementing 3D workflows for various cultural heritage purposes. 45 projects and institutions are reviewed, along with the most prominent guidelines for workflows and ways of implementing the 3D data on the web. We also cover how each project manage and make their data accessible to the public. Prominent and recurring issues with standardization, interoperability, and implementation is highlighted and scrutinized. The review is concluded with a discussion on the current utilization's of 3D data for cultural heritage purposes, along with suggestions for future developments. [ABSTRACT FROM AUTHOR]

The powdered form of various food products, including dairy-based and sugar-rich, is popular in the market due to their ease of processing and instant application. Spray drying is one of the most popular processing techniques to make food powders. The spray-drying process parameters, especially the drying temperatures and feed rate, have a significant influence on the quality attributes (such as color, moisture content, drying yield, wettability, water activity, proximate composition, and nutrient contents) of different food products. Recent studies revealed that at very high inlet/outlet air temperatures, the properties of the powdered products are adversely affected. Furthermore, sticking is a major problem during the spray-drying process. Keeping all these issues, this review focuses on providing insights on the effects of spray-drying process conditions and optimization of these conditions to overcome the problems associated with the process and ultimately obtain the best quality product with longer storage life. [ABSTRACT FROM AUTHOR]

The main objective of this work was to optimize the spray drying of coconut milk using response surface methodology (RSM). Maltodextrin was added to the feed coconut milk as the carrier agent in the laboratory scale experiments and the same were designed using Box-Behnken design approach. The effect of the chosen input variables on the responses namely product yield, moisture content, hygroscopicity, and angle of repose of the powders were evaluated using 3D surface plots. Among the chosen input variables of the process, the temperature of the inlet air in the spray drying chamber was found to significantly affect the characteristics of the powder. The flowability properties of the synthesized powders were experimentally obtained and the values were found to be satisfactory. The functional and morphological properties, and color of the powder produced at the optimal condition were compared to those of a commercially available coconut milk powder. For the synthesized powder of the optimal condition, an enhancement of 30oC for the glass transition temperature was seen over to that of the commercial powder. [ABSTRACT FROM AUTHOR]

Document forgeries that involve modification of the materials used, such as ink and paper, provide evidence of any malpractices being performed. Forensic specialists use different techniques to identify and classify these samples; however, the most preferred method is to use nondestructive techniques to avoid any potential damage to the original specimen under investigation. Hyperspectral imaging has already been explored in several application domains and used as a powerful method in forensic investigations to extract information about the materials under examination. To precisely classify the material information and utilize the hyperspectral imaging technique's potential, we probed the potential of some hybrid spectral similarity measures to classify different commonly used paper samples. A comparison of these methods is quantitatively presented in this article. Hybrid spectral similarity algorithms are tested on forensic analysis of paper data. We compared the classification capabilities of various hybrid spectral similarity algorithms on hyperspectral data of 40 different paper samples. The overall accuracy (OA), kappa K̂, Z‐score of kappa (ZK̂), and the 95% confidence interval of kappa (CI(K̂)) are used for comparison. The SID‐SAM and SID‐SCA produced an overall accuracy of 88% and 87%, respectively, which is highest among the hybrid spectral similarity measures tested. [ABSTRACT FROM AUTHOR]

Documentation and analysis of crime scene evidences are of great importance in any forensic investigation. In this paper, we present the potential of hyperspectral imaging (HSI) to detect and analyze the beverage stains on a paper towel. To detect the presence and predict the age of the commonly used drinks in a crime scene, we leveraged the additional information present in the HSI data. We used 12 different beverages and four types of paper hand towel to create the sample stains in the current study. A support vector machine (SVM) is used to achieve the classification, and a convolutional auto-encoder is used to achieve HSI data dimensionality reduction, which helps in easy perception, process, and visualization of the data. The SVM classification model was re-established for a lighter and quicker classification model on the basis of the reduced dimension. We employed volume-gradient-based band selection for the identification of relevant spectral bands in the HSI data. Spectral data recorded at different time intervals up to 72 h is analyzed to trace the spectral changes. The results show the efficacy of the HSI techniques for rapid, non-contact, and non-invasive analysis of beverage stains. [ABSTRACT FROM AUTHOR]

Glutathione (GSH), a non-protein thiol in living cells whose abnormal level indicates the onset of diseases like Alzheimer’s, HIV, diabetes, cancer, Parkinson’s, Dementia, etc. Herein, we have synthesized a low-cost, selective, and sensitive detection platform by using citric acid and urea-derived fluorescent carbon dots (NCDs) via the microwave-assisted method, showing fluorescence at 444 nm. This fluorescence was quenched with picric acid (PA), and this probe, picric acid incorporated nitrogen doped carbon dot (NCDs@PA) was further used for the detection of GSH. The characterization of the probe was done by photoluminescence study, UV-Visible absorption studies, ATR-FTIR, SEM, and DLS analysis. GSH induced fluorescence recovery due to the competitive binding of GSH to PA. GSH was detected within a linear range of 0.31 mM- 2.43 mM with a Limit of Detection (LoD) and Limit of Quantification (LoQ) of 32.10 µM and 107.32 µM, respectively. The sensor exhibited good selectivity and sensitivity towards GSH among various co-existing ions and biomolecules. The paper-strip-based sensing of glutathione was conducted to check practical applicability of the probe, and a real sample analysis was also conducted from spiked human samples. [ABSTRACT FROM AUTHOR]

Plant diseases significantly impact agricultural productivity. Early disease identification and diagnosis are critical for plant protection. Recent deep learning approaches have substantially aided detection of plant diseases. However, existing plant leaf disease identification techniques do not provide sufficient disease detection accuracies when the input image resolution is low. Images of grape leaves taken in the field may be low-resolution (LR) in nature due to limited lighting and varying weather conditions. Such LR images may result in incorrect real-time disease diagnosis. Hence super-resolution is a way to solve this problem. This research work proposes a novel Residual Skip Network-based Super-Resolution for Leaf Disease Detection (RSNSR-LDD) in the Grape plant. The input LR image is separated into two subcomponents using the guided filtering technique. Features from the two subcomponents are extracted using single convolutional layer and four layers of the two-channel residual skip network. Concatenation is used to combine the features of two channels. Following this, a decoding block and a convolutional layer are utilized to generate the super-resolution (SR) image. A new collaborative loss function is proposed for training. The obtained SR image is given to the Disease Detection Network (DDN) for grape leaf disease detection. This approach, based on an LR image, assists the farmer in spotting grape plant diseases very early. Proposed model was extensively trained and tested on PlantVillage, Grape 400, Grape Leaf Disease datasets with multiple super-resolution scaling factors for various grape leaves images. For different super-resolution scaling factors such as Χ2, Χ4, Χ6, the proposed model RSNSR-LDD achieved accuracies of 97.19%, 99.37%, and 99.06% for the PlantVillage dataset, 96.88%, 97.12%, and 95.43% for the Grape400 dataset, and 100% for the Grape Leaf Disease dataset. [ABSTRACT FROM AUTHOR]

In a previous article, we modelled the spectral and temporal dimensions of the photodegradation behaviour of pigments in the painting "A Japanese Lantern" by Oda Krohg. In particular, we extracted the endmembers and spectral fading rate of pigments by applying tensor decomposition on a time-series of spectroscopic point measurements. Now, we capture the same painting with a hyperspectral imaging setup and propose an approach to render the fading effects as 2D images. More precisely, from the hyperspectral image, we compute the concentration maps of each previously identified endmember with a least-squares unmixing method. Subsequently, by using tensor algebra, we multiply the concentration maps with the endmembers and their corresponding fading rate and obtain a 4D tensor where each pixel in the image is described by a spectrum and a fading function. This way, we generate past and future spatio-temporal simulations of the painting's appearance by reversing and elevating light exposure, respectively. [ABSTRACT FROM AUTHOR]

Photo-sensitive materials tend to change with exposure to light. Often, this change is visible when it affects the reflectance of the material in the visible range of the electromagnetic spectrum. In order to understand the photo-degradation mechanisms and their impact on fugitive materials, high-end scientific analysis is required. In a two-part article, we present a multi-modal approach to model fading effects in the spectral, temporal (first part) and spatial dimensions (second part). Specifically, we collect data from the same artwork, namely "A Japanese Lantern" by Norwegian artist, Oda Krohg, with two techniques, point-based microfading spectroscopy and hyperspectral imaging. In this first part, we focus on characterizing the pigments in the painting based on their spectral and fading characteristics. To begin with, using microfading data of a region in the painting, we analyze the color deterioration of the measured points. Then, we train a tensor decomposition model to reduce the measured materials to a spectral basis of unmixed pigments and, at the same time, to recover the fading rate of these endmembers (i.e. pure, unmixed chemical signals). Afterwards, we apply linear regression to predict the fading rate in the future. We validate the quality of these predictions by spectrally comparing them with temporal observations not included in the training part. Furthermore, we statistically assess the goodness of our model in explaining new data, collected from another region of the painting. Finally, we propose a visual way to explore the artist's palette, where potential matches between endmembers and reference spectral libraries can be evaluated based on three metrics at once. [ABSTRACT FROM AUTHOR]

Ethnopharmacological relevance Melicope lunu - ankenda leaves are used to treat diabetes in folklore medicinal practices in India and Malaysia. Here we report the isolation of an O -prenylated flavonoid (3,5,4′-trihydroxy-8,3′-dimethoxy-7-(3-methylbut-2-enoxy)flavone; OPF) from the leaves of M. lunu - ankenda and its antidiabetes activity against type-2 diabetes mellitus (T2DM). Materials and methods OPF was isolated from M. lunu - ankenda leaves by extraction and repeated column chromatography and its structure was elucidated by IR, UV–vis, 1D-, 2D-NMR and mass spectral analyses. Blood glucose lowering activity of OPF was tested in normal rats by oral glucose tolerance test and its efficacy was tested in STZ-induced type-2 diabetic rats. SGOT, SGPT, ALP, serum urea, total triglycerides, total cholesterol and reduction in HDLC, protein and serum insulin levels in normal rats and STZ-induced type-2 diabetic rats were measured. Acute toxicity of OPF was tested at 500 mg/kg dose. Mechanism of antidiabetes action of OPF was elucidated by insulin release from RIN 5F cells. Results OPF isolated from M. lunu - ankenda showed significant blood glucose lowering activity in oral glucose tolerance test on overnight fasted, glucose loaded normal rats and the optimum activity was observed at a dose of 10 mg/kg body weight. In neonatal streptozotocin (STZ) induced diabetic rats, the OPF treatment for 20 days significantly ameliorated the derailed blood glucose levels, liver glycogen and serum biological parameters including insulin to normal levels. OPF on acute toxicity evaluation did not show any conspicuous toxic symptoms even at a higher dose of 500 mg/kg body weight in mice. On evaluating the mechanism of antidiabetes action, it was observed that, OPF induced insulin release from cultured RIN 5F cells in vitro from which it was evident that the OPF acts on pancreatic β-cells for insulin release thereby correcting the derailed blood glucose levels, serum biochemical parameters and ameliorate various diabetic complications in STZ-induced diabetic rats. Conclusions This study shows the potent antidiabetes activity of OPF and describes its mechanism of action. OPF is a promising candidate for the development of new generation anti-DM drugs. Isolation of the O -prenylated flavonoid justifies the use of M. lunu - ankenda for diabetic treatments in folklore practices. [ABSTRACT FROM AUTHOR]

Abstract: A systemic investigation of expansion dynamics of plasma plume, produced by laser-blow-off of LiF–C thin film has been done with emphasis on the formation of shock wave and their dependence on the pressure and nature of the ambient gas. The present results demonstrate that highly directional plume produces a strong shock wave in comparison to shock produced by the diverging plume. Shock-velocity, strength and its structure are strongly dependent on ambient environment; maximum shock velocity is observed in helium whereas shock strength is highest in argon environment. The role of chemically reactive processes was not observed in the present case as the plume structure is almost similar in argon and oxygen. [Copyright &y& Elsevier]

A study has been carried out to understand the influence of ambient gases on the dynamics of laser-blow-off plumes of multi-layered LiF–C thin film. Plume images at various time intervals ranging from 100 to 3000 ns have been recorded using an intensified CCD camera. Enhancement in the plume intensity and change in size and shape occurs on introducing ambient gases and these changes are highly dependent on the nature and composition of the ambient gas used. Velocity of the plume was found to be higher in helium ambient whereas intensity enhancement is greater in argon environment. The plume shapes have maximum size at 10−2 and 10−1 Torr of Ar and He pressures, respectively. As the background pressure increases further (>10−2 Torr: depending on the nature of gas), the plume gets compressed/focused in the lateral direction. Internal structure formation and turbulences are observed at higher pressures (>10−1 Torr) in both ambient gases. [ABSTRACT FROM AUTHOR]

Abstract: The uniform surface activation characteristics of RuO2-coated Al–Zn alloy sacrificial anodes were studied in the present work. Electrochemical impedance spectroscopic and SEM/EDAX analyses were carried out to evaluate the galvanic dissolution characteristics of the anodes. The conventional electrochemical methods were also followed. Persistence and retention of catalytic RuO2 on the anode surface even after a large extent of galvanic dissolution of the anode surface was confirmed based on the EDAX spectroscopy. The anodes showed the same polarization performances even after the anodes were disintegrated to one-third of its original size, revealing the sustained catalytic activity of RuO2. [Copyright &y& Elsevier]

The work presented in this paper is part of a wider research project, which aims at documenting and analyzing stained glass windows by means of hyperspectral imaging. This technique shares some similarities with UV-VIS-IR spectroscopy, as they both provide spectral information; however, spectral imaging has the additional advantage of providing spatial information, since a spectrum can be collected in each pixel of the image. Compared to UV-VIS-IR spectroscopy, spectral imaging has rarely been used for the investigation of stained glass windows. One of the objectives of this paper is, thus, to compare the performance of these two instruments to validate the results of hyperspectral imaging. The second objective is to evaluate the potential of analyzing colored-glass pieces in reflectance modality and compare the results with those obtained in transmittance, in order to highlight the differences and similarities between the two approaches. The geometry of the systems and the backing material for the glass, as well as the characteristics of the glass pieces, are discussed. L*a*b* values obtained from the spectra, as well as the calculated color difference ΔE00, are provided, to show the degree of agreement between the instruments and the two measurement modalities. [ABSTRACT FROM AUTHOR]

Bilirubin (BR), a heme protein produced from breakdown of haemoglobin is present in aged red blood cells; whose abnormal concentration is associated with diseases like hyperbilirubinemia, coronary disease, iron deficiency, and so on. Herein, we have synthesized a selective, sensitive, and low-cost sensing platform using fluorescent nitrogen doped carbon dots (NCDs), prepared from precursors; citric acid and urea via a simple microwave-assisted method. The emission at 444 nm on excitation with 360 nm was well quenched in presence of BR suggesting a direct turn-off detection for BR. Characterization of developed probe was done by UV-Visible absorption studies, photoluminescence studies, SEM, TEM, ATR-FTIR, XPS, and DLS analysis. BR was detected with a Limit of Detection (LoD) and Limit of Quantification (LoQ) of 0.32 µM and 1.08 µM respectively. NCDs exhibited excellent selectivity and sensitivity towards BR in the presence of co-existing biomolecules and ions. Practical feasibility was checked by paper-strip-based sensing of BR and spiked real human samples were used for conducting real sample analysis. [ABSTRACT FROM AUTHOR]

In terms of both international public security and environmental protection, nitroaromatic explosive substances like 2,4,6-trinitrophenol (TNP) receive great concern, and its detection has relevance in health sector as well. Herein, we have synthesized a fluorescent sensor for easy and fast detection of TNP. Sulphur and nitrogen-doped carbon dots (S,N-CDs) were synthesized via microwave irradiation method using L-cysteine as the sulphur and nitrogen donor and citric acid as the carbon source. The prepared S,N-CDs were examined by various analytical techniques, such as DLS, photoluminescence (PL) studies, UV–visible absorption studies, lifetime analysis, FT-IR, TEM, and SEM analysis. The developed S,N-CDs can act as a selective fluorescent probe for TNP. S,N-CDs show a detection limit of 0.29 µM and a limit of quantification of 0.95 µM towards TNP with appreciable selectivity and sensitivity. Thus, a fast and easy direct turn-off detection of TNP is developed by this fluorescence sensing platform. Further, TNP detection on a paper-strip based sensing platform was also performed. [ABSTRACT FROM AUTHOR]

We study the relationship between reflectance and the degree of linear polarization of radiation that bounces off the surface of an unvarnished oil painting. We design a VNIR-SWIR (400 nm to 2500 nm) polarimetric reflectance imaging spectroscopy setup that deploys unpolarized light and allows us to estimate the Stokes vector at the pixel level. We observe a strong negative correlation between the S0 component of the Stokes vector (which can be used to represent the reflectance) and the degree of linear polarization in the visible interval (average -0.81), while the correlation is weaker and varying in the infrared range (average -0.50 in the NIR range between 780 and 1500 nm, and average -0.87 in the SWIR range between 1500 and 2500 nm). By tackling the problem with multi-resolution image analysis, we observe a dependence of the correlation on the local complexity of the surface. Indeed, we observe a general trend that strengthens the negative correlation for the effect of artificial flattening provoked by low image resolutions. [ABSTRACT FROM AUTHOR]

An enzymatic fluorescent probe is developed for the selective detection of glucose. In this work, a Bovine Serum Albumin stabilized gold nanocluster (BSA‐AuNCs) was synthesized by microwave assisted method, and it is modified with glucose oxidase, thereby a fluorescent enzymatic sensor (BSA‐AuNCs@GoX) was designed for the sensitive detection of glucose with a limit of detection of 0.03 mM. The red fluorescence exhibited by the probe is quenched by the production of H2O2 on addition of glucose via. a static quenching mechanism from UV visible absorption and Fluorescence lifetime results. The developed probe exhibits good selectivity and sensitivity with other coexisting molecular species such as glycine, creatinine, methionine, histidine, uric acid, albumin, and ions such as sodium, potassium, calcium, magnesium, zinc etc. that appear in the body fluid. The practical applicability was studied in paper strip and extended its reproducibility in biological matrixes such as human serum and urine and found a good recovery percentage of 94–101 %. By this way, we have fabricated an effective fluorescent enzymatic "turn‐off" sensing probe for the detection of glucose. [ABSTRACT FROM AUTHOR]

L‐3,4‐dihydroxyphenylalanine (levodopa or L–DOPA) a precursor of neurotransmitter dopamine, has been universally prescribed as a gold standard for treatment of Parkinson's Disease (PD). However, direct administration of L–DOPA has risky adverse effects which makes it challenging in the treatment of PD. Hence developing simple detection platform for sensing of L–DOPA is significant. In this work, we have developed cysteine stabilized copper nanocluster quenched with Fe2+ (Fe2+@cys@CuNC) and used as both fluorescent and colorimetric probe for detection of L–DOPA. L–DOPA attributed a fluorescence quenching effect on developed probe. Fe2+@cys@CuNC detected L–DOPA within a linear range from 0.06 mM to 1.31 mM with a low limit of detection (LoD) of 6.57 nM. The probe also exhibited high selectivity for L–DOPA over other biomolecules and neurotransmitters. Furthermore, the capability of this probe was validated by sensing L–DOPA from human serum with excellent recovery rates of 85.75 % to 115.07 %. A low‐cost paper strip‐based portable detection platform was also developed for visual detection of L–DOPA. [ABSTRACT FROM AUTHOR]

The virtual inpainting of artworks provides a nondestructive mode of hypothesis visualization, and it is especially attractive when physical restoration raises too many methodological and ethical concerns. At the same time, in Cultural Heritage applications, the level of details in virtual reconstruction and their accuracy are crucial. We propose an inpainting algorithm that is based on generative adversarial network, with two generators: one for edges and another one for colors. The color generator rebalances chromatically the result by enforcing a loss in the discretized gamut space of the dataset. This way, our method follows the modus operandi of an artist: edges first, then color palette, and, at last, color tones. Moreover, we simulate the stochasticity of the lacunae in artworks with morphological variations of a random walk mask that recreate various degradations, including craquelure. We showcase the performance of our model on a dataset of digital images of wall paintings from the Dunhuang UNESCO heritage site. Our proposals of restored images are visually satisfactory and they are quantitatively comparable to state-of-the-art approaches. [ABSTRACT FROM AUTHOR]

The dynamics of plasma plume, formed by the laser-blow-off of multicomponent LiF-C thin film under various ambient pressures ranging from high vacuum to argon pressure of 3 Torr, has been studied using fast imaging technique. In vacuum, the plume has ellipsoidal shape. With the increase in the ambient pressure, sharp plume boundary is developed showing a focusing-like (confinement in the lateral space) behavior in the front end, which persists for long times. At higher ambient pressure (>10-1 Torr), structures are developed in the plasma plume due to hydrodynamic instability/turbulences. [ABSTRACT FROM AUTHOR]

Ink analysis is an important tool in forensic science and document analysis. Hyperspectral imaging (HSI) captures large number of narrowband images across the electromagnetic spectrum. HSI is one of the non-invasive tools used in forensic document analysis, especially for ink analysis. The substantial information from multiple bands in HSI images empowers us to make non-destructive diagnosis and identification of forensic evidence in questioned documents. The presence of numerous band information in HSI data makes processing and storing becomes a computationally challenging task. Therefore, dimensionality reduction and visualization play a vital role in HSI data processing to achieve efficient processing and effortless understanding of the data. In this paper, an advanced approach known as t-Distributed Stochastic Neighbor embedding (t-SNE) algorithm is introduced into the ink analysis problem. t-SNE extracts the non-linear similarity features between spectra to scale them into a lower dimension. This capability of the t-SNE algorithm for ink spectral data is verified visually and quantitatively, the two-dimensional data generated by the t-SNE showed a better visualization and a greater improvement in clustering quality in comparison with Principal Component Analysis (PCA). [ABSTRACT FROM AUTHOR]

A selective fluorescence turn-on immunosensor for the specific detection of cardiac troponin I (cTnI), the potent biomarker for myocardial infarction diagnosis, was developed with a nano couple comprised of protein-stabilized gold nanocluster and gold nanoparticle. The red fluorescence of cTnI-specific antibody tagged bovine serum albumin stabilized gold nanoclusters was quenched with gold nanoparticles (AuNP) via the intensive interaction between amine and hydroxyl functionalities of BSA and AuNP. Through this, the adsorption of gold nanoclusters at the surface of AuNP, resulting in a core-satellite assembly, was assumed to quench the fluorescence emission. While in the presence of cTnI antigen, this gets disturbed due to the formation of immunocomplex between cTnI antigen and antibody, which restricts the close interaction between gold clusters and nanoparticles, thereby restoring quenched fluorescence. The enhancement in fluorescence signal is directly related to the concentration of cTnI, and this facilitates the selective detection of cTnI in the linear concentration range 0.7 to 10 ng/mL without any interference from other potentially interfering co-existing biomolecules. An appreciable limit of detection of 0.51 ng/mL and a limit of quantification of 0.917 ng/mL for cTnI is comparable to that of the previous report. [ABSTRACT FROM AUTHOR]

Glutathione (GSH), an oxidative stress biomarker plays a major role in different pathological processes and lead to a vast number of diseases including cancer. Biologically, cystine uptake is a fundamental factor in maintaining GSH levels in cells; however, the interaction between cystine and GSH in biological systems is least explored in developing sensors for GSH. In the present work, we have explored this interaction as the fundamental factor in "turn‐on" sensing of GSH from body fluids using a fluorescent gold nanocluster platform. The experimental results revealed that the probe displayed appreciable performance for GSH over a linear range from 0.2 mM to 1.3 mM with a limit of detection (LoD) of 0.43 μM. The probe also revealed sensitive as well as selective response towards GSH even in the presence of possible co‐existing interferants and provided satisfactory recovery percentage of 94.17 % to 108.12 % from real serum samples. These findings of the present study can be extended in future applications of sensing GSH from clinical samples. [ABSTRACT FROM AUTHOR]

Cardiac troponin I (cTnI) is a significant biomarker for acute heart attack. Hence, fast, economical, easy and real time monitoring of cardiac troponin I (cTnI) is of great importance in diagnosis and prognosis of heart failure in the healthcare domain. In this work, an immunoassay based on NaYF4:Yb/Ho based photon-upconversion nanoparticle (UCNP) with narrow emission peaks at 540 nm and 655 nm respectively, is synthesized. Then, it is encapsulated with amino functionalized silica using 3-aminopropyltriethoxysilane (APTES) to form APTES@SiO2-NaYF4:Yb/Ho UCNPs. When AuNPs is added to this system, the fluorescence is quenched by the electrostatic interaction with APTES@SiO2-NaYF4:Yb/Ho UCNPs, thereby exhibiting a FRET-based biosensor. When the cTnI antigen is introduced into the developed probe, an antibody–antigen complex is formed on the surface of the UCNPs resulting in fluorescence recovery. The developed sensor shows a linear response towards cTnI in the range from 0.1693 ng mL−1 to 1.9 ng mL−1 with a low limit of detection (LOD) of 5.5 × 10−2 ng mL−1. The probe exhibits adequate selectivity and sensitivity when compared with coexisting cardiac biomarkers, biomolecules and in real human serum samples. [ABSTRACT FROM AUTHOR]

Hyperspectral (HS) imaging captured at low proximity ranges has become an effective method for assessing the quality and safety of food products in recent years. The majority of Hyperspectral cameras are push-broom type, which often contributes random noise and stripes to the spectral images. As a result, the quality of the collected HS images and the precision of the subsequent processing will both suffer. Despite the fact that there are several denoising techniques that have been studied and recorded in the literature, they frequently fail to fully restore the original HS images when there are strong stripe noises and other intricate mixed noises. In this study, we introduce a new method based on tensor logarithmic Schatten- p norm minimization with anisotropic spatial spectral total variation (ASSTV) regularization for simultaneous denoising and destriping of line scan-based hyperspectral images. Tensor logarithmic Schatten- p norm improves denoising performance by deleting the smaller singular values while protecting the larger singular values. Through the application of ASSTV, stripes and Gaussian noise are eliminated while maintaining the spatial–spectral smoothness of HS images and the directional characteristics of the stripes. The augmented Lagrange multiplier (ALM) approach is used to address the ensuing optimization problem. The quantitative and visual assessments reveal that the suggested technique has improved performance than its counterparts. • A new method for noise removal from spectral images of fruits is proposed. • Tensor logarithmic Schatten-p norm minimization improves noise attenuation. • ASSTV regularization improves the spatial–spectral smoothness of the image. • The method is tested on real and simulated noisy hyperspectral images of fruits. • An extensive evaluation of the results proves the effectiveness of the method. [ABSTRACT FROM AUTHOR]

Neopterin (NPT) is a Guanosine Tri Phosphate (GTP) metabolite produced by activated macrophages and is considered a pro‐inflammatory and atherosclerotic agent. Beyond this NPT is a multi‐utility biomarker for assessing the status of various diseases including cardiovascular disease, depression, and malignant tumors as well as infections including viral and bacterial origin. Recent clinical investigations suggest the use NPT as a prognostic marker for the early prediction of the severity of Covid‐19, which is the prime concern of global public health. One of the main immunopathological characteristics of Covid‐19 is an excessive inflammatory response, and the severity of the infection is linked with macrophage activation syndrome (MAS). Hence the assessment of neopterin serves as an effective diagnostic tool for the risk prediction of Covid‐19. We present a fluorescence turn‐on sensor for neopterin using ferric ion‐modulated sulfur and nitrogen co‐doped carbon quantum dots. The linear detection of NPT was achieved with a limit of detection of 3.11 nM. [ABSTRACT FROM AUTHOR]

Over the last decade, hyperspectral imaging has become a popular technique for the non-invasive identification and mapping of painting materials in many typologies of artworks, thanks to the possibility of obtaining spectral information over the spatial region. A few attempts have also been made on stained-glass windows to identify the chromophore elements responsible for glass color. Hyperspectral imaging of stained glass can be complex; in most cases, stained-glass windows are an integral part of buildings, and sunlight represents the natural light source for illuminating these artifacts. While it may be considered an advantage, sunlight is not homogeneous throughout the day, and different weather conditions can affect the quality of the hyperspectral images. In addition, the presence of buildings and vegetation in the background could also modify the colors of the stained-glass windows and consequently alter the characteristic peaks of the chromophores in the spectra. This work aims to solve some of these issues and proposes different strategies to improve the results obtainable in situ. The methodology was tested on stained-glass panels displayed in the windows of the Swiss National Museum. Stained-glass panels located in windows of an internal wall were also analyzed, developing a lighting setup to account for the lack of natural light. Hyperspectral images of the selected stained glass were acquired multiple times, choosing different transmittance references for the preprocessing and exposure time to evaluate differences in the collected spectral images. The use of a diffuser sheet to mitigate the effect of external factors was also tested on some panels exposed to sunlight. Results from representative case studies will be presented to discuss the feasibility and limitations of in-situ hyperspectral imaging applications on stained glass and provide some general recommendations to consider during the acquisitions. [ABSTRACT FROM AUTHOR]

Rapid, reliable, onsite approaches for the trace level detection of trinitrotoluene (TNT) is a pressing necessity for both homeland security and environmental protection. Selective detection of TNT from other nitroaromatics is still challenging as it possess similar chemical structure and properties with its analogues. In the present work, the water soluble polyethylene imine protected copper nanoclusters (PEI CuNC) were developed as fluorescent and colorimetric probe which can detect TNT selectively and sensitively both in aqueous and vapour form. The PEI CuNC with size less than 3 nm was prepared via a simple one pot microwave method and exhibited bright blue emission at 480 nm. The fluorescence of PEI CuNC can be remarkably quenched by TNT through the formation of amine-TNT Meisenheimer complex. Quenching was further facilitated by fluorescence resonance energy transfer (FRET) and inner filter effect (IFE). A good linearity was observed for the PEI CuNC based fluorescence detection of TNT with limit of detection 14 pM. Meanwhile the formation of Meisenheimer complex resulted in a significant colour change of the solution from pale green to red, which enables visual detection of TNT with detection limit down to 0.05 nM. The fluorescence as well as colorimetric method displayed excellent selectivity and sensitivity over other interfering compounds and ions. Fluorescent paper strip sensor was developed to detect TNT in vapour phase as well as solution form. PEI CuNC coated paper strips were able to detect TNT vapours with in one minute with a limit of detection 10 nM, providing a valuable platform for sensing TNT in public safety and security. [ABSTRACT FROM AUTHOR]

The authors report Ho ion incorporated and fluorescent dye-doped silica nanoparticles which are engineered to enable the imaging modalities of receptor targeted fluorescence imaging (FI) and magnetic resonance imaging (MRI). The silica nanoparticles synthesized through a modified Stöber method is luminomagnetic by virtue of the luminescence of organic dye fluorophore (FITC) and magnetism of Ho. The doping concentration of Ho is estimated by inductively coupled plasma mass spectrometry (ICP-MS) as 0.97%. The presence of Ho has a little effect on the luminescence intensity but impart strong paramagnetism of 27.217 emu/g at room temperature. The relaxivity measurements shown that the nanoparticles exhibit a longitudinal relaxivity (r) of 0.12 s mM and transverse relaxivity (r) of 26.96 s mM, which makes the system potentially suitable for developing T2 MRI contrast agents based on holmium. The luminomagnetic nanoparticles were surface engineered through aminization and conjugated with folic acid (FA) to address the folate receptor targeted imaging of the cancer cells. The biocompatibility studies revealed no apparent toxicity even at higher doses of 750 μg/mL and at 48 h of incubation. The as prepared nanoparticles were demonstrated as a bioimaging probe in the in vitro receptor targeted fluorescence imaging of HeLa cells. The luminescence and magnetism together with biocompatibility enables the adaptability of the present system as a nano platform for potential bimodal imaging. [ABSTRACT FROM AUTHOR]

The authors report on the development of copper nanocluster stabilized with tannic acid (TA CuNC) as a fluorescent nanoprobe for the turn on detection of a catecholamine neurotransmitter, dopamine. The nanocluster is obtained through a microwave assisted synthesis and exhibit distinct blue emission peak at 450 nm during excitation at 370 nm. The luminescence in the present system is effectively quenched by Fe(III) ions. The quenching happens through an electron transfer mechanism, which operate between the nanocluster and Fe(III) ions. The quenching is linear proportional to the concentration of Fe(III) between 0.25 and 1 μM and the detection limit is as low as 1.28 nM. Addition of dopamine into the quenched system causes the removal Fe(III) ions from the cluster surface and thereby leads to the retrieval of luminescence. The quenched system exhibited high sensitivity and selectivity for dopamine with a limit of detection 45 nM. The adaptability of the nanocluster as a turn on fluorescent probe is tested in real samples for the detection of dopamine and the recovery of fluorescence is in the range of 95%. [ABSTRACT FROM AUTHOR]

A new fluorescent probe based on Eu (III) incorporated BSA‐AuNCs is developed for the selective sensing of sarcosine. Sarcosine is a simple non‐proteinogenic amino acid which is a clinical biomarker for prostate cancer. The non‐invasive sensing of a metabolite biomarker sarcosine for prostate cancer from urine sample was achieved through the developed Eu (III) incorporated BSA‐AuNCs probe. The developed sensor exhibited a good sensitivity and selectivity towards the metabolite sarcosine and observed no significant interference with other coexisting metabolites present in urine. The probe shows a very lower Limit of detection (LOD) of 0.177 mM and this probe can be developed for determining sarcosine on clinical basis. Considering its predominance and the pain associated invasive prostate cancer clinical examinations for the diagnosis, a non‐invasive diagnosis is of great need and significance. [ABSTRACT FROM AUTHOR]

Dipicolinic acid (DPA) is a prominent biomarker for Anthrax disease. Bacillus anthracis bacterial endospores is composed of DPA as the significant component, which on over inhalation can cause severe health issues. Such contagious and life-threatening pathogens can be employed as bioweapons or biothreat agents for spreading bioterrorism which is a major risk for national security and public health concerns. Hence, effective detection or a surveillance system is essential for preventing the growth of bioterrorism events. Herein, we have developed a Terbium − 1,10 Phenanthroline (Tb-Phen) based lanthanide luminescence complex with bright green fluorescence. On addition of DPA, the green fluorescence is turn-off at a linear range from 0.6 to 4.762 mM. In this effect, 5D4– 7F5 transition caused by 1,10-phenanthroline to Tb3+ at 544 nm is restricted due to energy transfer quenching and Inner Filter Effect (IFE). The developed probe shows good sensitivity towards the detection of DPA with other coexisting biomolecules and ions with a low Limit of Detection (LOD) of 5.029 µM. The practical feasibility was evaluated in paper strip assay and extended in real samples such as human serum and tap water with satisfactory recovery percentage. Thereby, probe finds promising application in sensing of anthrax spore biomarker (DPA) and biothreat agents. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pre-Columbian textiles were studied using hyperspectral imaging (400–2500 nm). • Spectral unmixing was used to identify endmembers of possible dye mixes. • Both an a priori and an automatic processing approach were used to define endmembers. • The selected endmembers were mapped to reveal patterns of dyes and fiber materials. • A comparison between maps obtained with the two selection approaches is provided. In this study, two pre-Columbian textiles belonging to the Middle Orizon and Necropolis Paracas Cultures are studied by means of reflectance imaging spectroscopy. The non-invasive analysis of artifacts is a fundamental step when investigating the constituent materials and their state of conservation in order to target subsequent sampling campaigns in specific areas. The paper aims to explore the spectral properties in the Visible Near-Infrared (VNIR) and Short-Wave Infrared (SWIR) intervals and investigate the spectral correlation between the relevant identified regions of interest. Two ways of selecting relevant spectral signatures are proposed: manual selection and automatic filtering. According to these two selections, the regions of interest undergo spectral unmixing in the VNIR interval to investigate which dyes had been used as such. The hyperspectral images are then mapped according to the selected endmembers in both VNIR and SWIR intervals. Small areas that feature the usage of a peculiar black thread have been given particular attention and imaged with a macro objective. The SWIR mapping on one of the samples has helped to reveal a pattern that can be ascribed to the manufacturing processes or the burial conditions. [ABSTRACT FROM AUTHOR]

Troponin I, as a cardiac-specific biomarker, is a very valuable tool in the identification of acute coronary syndromes. In this work, an economical technique for easy and sensitive diagnosis of cardiac troponin I (cTnI) was developed nanoprobe on the basis of graphene oxide quenching of the fluorescence of bovine serum albumin–capped fluorescent nickel (BSA@NiNCs) nanoclusters. The developed nanoprobe nickel nanocluster exhibited superparamagnetism. The nanoprobe showed a fluorescence turn-on behavior toward incremental addition of in cTnI, with a detection limit of 0.012 ng/mL. We successfully used the proposed sensing technique for cTnI sensing in serum samples. [ABSTRACT FROM AUTHOR]

Schematic Representation of developed fluorescent "Turn-off" sensor for the detection of bilirubin. [Display omitted] • Bright green Tb-DPA luminescent complex was designed. • Tb-DPA act as a luminescent probe for the detection of bilirubin. • Selectivity and sensitivity with other coexisting biomolecules were evaluated. • Real sample analysis is performed in human serum and urine samples and obtained satisfactory result. The sensitive and selective fluorescent probes for biomolecule detection have significant application in clinical diagnosis and bioanalysis. Hyperbilirubinemia is a disease condition in which the excessive or less production of bilirubin in blood resulting in jaundice. In this work, we have synthesised Terbium based bright green, fluorescent lanthanide complex (Tb-DPA) with emission at λ em = 544 nm for the detection of Bilirubin. A one-step synthesis approach was adopted with 2,6-pyridine dicarboxylic acid (DPA) as ligand and Sodium dodecyl sulphate (SDS) as surfactant. The green fluorescence of Tb-DPA was quenched with the addition of bilirubin due to the inner filter effect mechanism. The fluorescence intensity of Tb-DPA decreases as bilirubin concentration increases and a linear " turn-off " response is obtained. Even in presence of other coexisting biomolecules and ions, the Tb-DPA probe exhibited good selectivity and sensitivity for the detection of bilirubin. The limit of detection (LOD) of 2.6 mg/dL was obtained. Furthermore, the proposed fluorescent probe was applied in Human serum and urine samples with satisfactory recoveries in the range of 92–122 %. Based on the result obtained, it has probability to be used as a rapid detection method for bilirubin in biological samples at bedside. [ABSTRACT FROM AUTHOR]

• Blue, fluorescent chiral carbon dots are synthesised using L/D methionine by microwave assisted method with emission at 450 nm. • Fe (II) is doped to these L/D MCDs separately resulting in quenching of fluorescence. • On addition of l-cysteine to the system, it competitively binds Fe (II) ions from the CDs surface causing fluorescence recovery of MCDs. • The probe positive results in spiked human serum sample with LOD of 0.71 µM and 0.94 µM for l-MCDs and d-MCDs. Chiral carbon dots have prominently influenced in the field of chemical, biological, and medicinal research. Comparing to achiral carbon dots, chiral carbon dots exhibit unique characteristics in biosensing application. In this perspective, we have developed bright blue, fluorescent L and d-Methionine Chiral carbon dots (MCDs) using a simple microwave assisted process for effective sensing of l-Cysteine. l-Cysteine plays a vital role in balancing the physiological redox in the body. These MCDs can be complexed with Fe2+ ions to create an energy transfer quenching system due to distinctive N and S functional group distribution on their surface. However, l-Cysteine attaches to Fe2+ ions in a competitive manner, leads to recovery of MCDs fluorescence. As a result, a " turn-on " fluorescent sensing platform based on L and d-Methionine-CDs has been developed for the rapid identification and detection of l-Cysteine. The probe shows good selectivity and sensitivity with coexisting biomolecules and ions. From comparative PL studies, d- MCDs are more responsive than l-Meth CDs towards the detection of l-cysteine with LOD of 0.71 µM and 0.94 µM respectively. The chiroptical properties were evaluated and the probe extends its practical application in paper strip and in biological matrix such as human blood serum with satisfactory recoveries in the range 85–104%. [Display omitted] [ABSTRACT FROM AUTHOR]

A "turn-on" photon up conversion nano couple based on NaYF 4 : Yb, Tm UCNPs quenched with MnO 2 nanosheet was developed for the rapid and selective detection of cTnT. Herein, MnO 2 nanosheet hold on the surface of Antibody cTnT (Ab-cTnT) conjugated blue emitting up conversion nanoprobe (λ em at 475 nm), which leads to quenching of fluorescence due to energy transfer from photon up conversion nanoparticles to MnO 2 nanosheets. On introducing cTnT antigen to the system, the energy transfer process is hindered due to strong antigen -antibody interface on the surface. This in turn, influences the nano-couples positions and effectively separates up conversion nanoprobe from MnO 2 nanosheets surface resulting in restriction to energy transfer process enabling fluorescence recovery. The developed probe shows a linear response towards cTnT in the range of 0.16–2.77 ng/mL with a Limit of Detection (LoD) of 0.025 ng/mL. The practical feasibility of the nanoprobe is performed with possible coexisting biomolecules. Biological study in human blood serum samples exhibited sufficient recovery percentage in the range of 92–103 % is obtained. [Display omitted] • Blue emitting Thulium doped photon-upcoversion nanoprobe coupled with MnO 2 NS for the detection of cTnT was developed. • Surface modification with PEI to form PEI@NaYF 4 : Yb, Tm UCNPs. • Ab-cTnT is conjugated on the surface of PE1@ NaYF 4 : Yb, Tm UCNPs via. EDC-NHS coupling. • The luminescence intensity of the immunoprobe is quenched by the addition of nanosheet. • The luminescence intensity is "turn-on" with linear response from 0.016 to 2.7 ng/mL with a LoD of 0.025 ng/mL. [ABSTRACT FROM AUTHOR]

Lead halide perovskites are an advanced class of materials with high photoluminescence and optoelectronic properties. However their instability towards moisture and lead toxicity hinders their applications especially in biological sensing. Hence the need for novel lead free perovskite nanocrystals are of utmost important. Herein we synthesized a lead free, highly efficient, stable, cost effective Cs 2 ZnCl 4 perovskite nanocrystals (PNCs) and extends its application in biosensing. The PNCs exhibits bright blue fluorescence upon UV irradiation and was able to selectively detect bilirubin (BR) - a clinically important jaundice biomarker. The intense fluorescence emission of the sensor was completely quenched upon the addition of bilirubin. The sensor could detect bilirubin even in the presence of other interfering biomolecules with a good limit of detection of 26.10 nM. The sensor could successively detect BR in human serum samples. Furthermore, for the visual detection of bilirubin, a paper strip sensor was also designed making the sensor more economical and adaptable. [Display omitted] • Lead free Cs 2 ZnCl 4 Perovskite nanocrystals were synthesized as the fluorescent probe. • The fluorescence intensity of the probe was drastically quenched upon bilirubin addition. • The sensor displayed a good selectivity and sensitivity towards bilirubin over other coexisting biomolecules. • The sensor shows an accurate recovery percent when applied to human serum samples. • For rapid visual detection, a paper strip sensor was also developed. [ABSTRACT FROM AUTHOR]

Graphical representation of fluorescence turn-on detection of BNP antigen-by-BNP specific antibody tagged gold nanoclusters – MoS 2 nanosheet nano couple. [Display omitted] • An easy and prompt method for the detection of heart failure biomarker was achieved with gold nanocluster / 2D MoS 2 nanosheets. • A stable fluorescence turn - on response was observed with the probe in presence of BNP in physiologically significant serum concentration levels. • The development of the probe and detection of BNP antigen can be achieved within minutes without any high-end instruments. • The probe exhibited a low detection limit of 0.165 pg/mL. In the context of elevated morbidity and mortality risk of heart failure (HF), the establishment of prompt and sensitive diagnosis of HF is vital. A nanostructured fluorescence immuno sensing probe was constructed out of noble metal nanoclusters / two-dimensional transition metal dichalcogenide nano couple to target brain natriuretic peptide (BNP) antigen, a potential multi-utility heart failure biomarker. The green fluorescence of BNP-specific monoclonal antibody-conjugated gold nanoclusters was pre-quenched by a MoS 2 two-dimensional nanosheet, which is subsequently enhanced in the presence of BNP antigen via target-specific antigen–antibody interaction. The probe is free from interferences by other potentially interfering possible co-existing biomolecules and offers easy, low-cost linear detection of BNP in the concentration range 0 to 360.82 pg/mL. [ABSTRACT FROM AUTHOR]

We present a nano couple platform for the detection of cardiac biomarker in which the pre-quenched fluorescence of monoclonal antibody conjugated nano fluorophore was lighted up successfully by the utilization of immunocomplex formation between antigen and antibody. Folic acid-capped fluorescent gold nanoclusters were surface-engineered with cardiac troponin-T(cTnT) specific monoclonal antibody through carbodiimide chemistry. Further, its fluorescence was quenched with a two-dimensional nanosheet made of MnO 2. This pre-quenched nano couple can detect the presence of cTnT selectively by giving an enhanced fluorescence signal proportional to the concentration of cTnT antigen. The specific detection was manifested by the specific antigen-antibody interaction forming an immunocomplex, disrupting the direct contact of cluster and two-dimensional sheet. • Target-specific antibody-tagged 0D nanoclusters / 2D nanosheets fluorescence probe for cardiac biomarker was developed. • A standard cardiac biomarker, cardiac troponin T (cTnT) antigen, was probed successfully. • The antibody-tagged gold nanoclusters/MnO 2 nano couple gave a stable fluorescence turn-on signal with cTnT antigen. • The probe successfully detected clinically relevant concentrations of cTnT antigen in aqueous media and human serum samples. • A low-cost paper-based assay strip with this probe successfully detected the presence of cTnT antigen. [ABSTRACT FROM AUTHOR]

Oral Squamous Cell Carcinoma (OSCC), a prevalent type of oral cancer originates in squamous cells that develop due to tobacco use, excess alcohol consumption, human papillomavirus infection, chronic irritation and weakened immune system. When detected early, survival rates of OSCC can be increased to more than 85%. Hence its early detection is crucial for appropriate management. Oxidative stress has a vital role in pathogenesis of various cancers including OSCC. Early detection of OSCC can be done by exploring serum Glutathione (GSH); an oxidative stress biomarker. Herein, we have developed two Silicon quantum dots (SiQDs); (L-methionine capped Silicon quantum dots (LSiQDs) and D-methionine capped Silicon quantum dots (DSiQDs)) and their fluorescence was quenched with Cu2+. The obtained Cu@LSiQDs and Cu@DSiQDs were then explored and compared for sensing GSH. Both the SiQDs were checked for selectivity and interference studies using coexisting biomolecules extended for sensing GSH from real samples. Moreover, a paper strip assay was also developed and compared. [ABSTRACT FROM AUTHOR]

Several studies have been focusing on alloying and structural modification of aluminium alloy sacrificial anodes using different activators including intermetallic compounds. With a novel approach, the present work explore and evaluate the feasibility of effective aluminium activation by RuO2 in 95 + 5 Al–Zn alloy substrates. The electrodes prepared in the present work, by making RuO2 film on the substrate, were found to possess good surface interaction, low surface resistivity and facilitate interlayer diffusion of aluminium ions. The electrodes showed excellent galvanic performance under different experimental conditions in 3% NaCl electrolyte. The RuO2 layer was found to persist on the electrode surface even after the electrode size was reduced to one-third of its original size due to long period of galvanic exposure, evidencing its mobile character. The electrodes are economically efficient, convenient to prepare as other conventional hanging electrodes, tolerable to very aggressive media and highly efficient even under high current load. [Copyright &y& Elsevier]

Rapid and onsite detection of nitroaromatic explosive 2,4,6-trinitrotoluene (TNT) is very crucial for the safety and security of human life as well as for the environment. In this present work, we demonstrate the feasibility for employing Folic Acid (FA) as a fluorescent as well as a colorimetric probe for the detection of TNT. This probe was synthesized by a simple one-step process. The developed probe shows an emission maximum at 490 nm upon excitation at 420 nm. On adding TNT, the fluorescence of the FA probe is quenched. Also, it shows a good selectivity towards TNT over other similar organic compounds such as 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP) and picric acid (PA). The limit of detection (LoD) of TNT was found to be 1.9398 µM. Colorimetric detection was conducted and paper strip assay was developed for the practical applications. [ABSTRACT FROM AUTHOR]

The radiation captured in spectral imaging depends on both the complex light–matter interaction and the integration of the radiant light by the imaging system. In order to obtain material-specific information, it is important to define and invert an imaging process that takes into account both aspects. In this article, we investigate the use of several mixing models and evaluate their performances in the study of oil paintings. We propose an evaluation protocol, based on different features, i.e., spectral reconstruction, pigment mapping, and concentration estimation, which allows investigating the different properties of those mixing models in the context of spectral imaging. We conduct our experiment on oil-painted mockup samples of mixtures and show that models based on subtractive mixing perform the best for those materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple, sensitive and economically feasible fluorescence immunoassay for cTnI antigen was developed. • The immunosensor was based on MPA capped Mn2+ doped ZnS QDs and MnO 2 nanosheets as the FRET couple. • The probe was able to detect cTnI antigen linearly from 0 to 2 ng/mL with a low LoD of 0.05 ng/mL. • The selectivity of the developed probe was assessed in the presence of other potential interferants and other cardiac biomarkers. • Good recovery percentage was obtained for cTnI detection from human serum samples. Acute Myocardial Infarction (AMI) is the persisting serious threat among all cardiovascular diseases due to its highest mortality rates. Clinicians resort to biomarker levels pertinent to AMI in triaging patients. Among the several cardiac biomarkers, by virtue of the specificity and sensitivity, cardiac troponin I (cTnI) was recognized as the gold standard for AMI diagnosis. Immunosensors that have been developed for cTnI detection are limited by multistep process and long diagnostic time which makes them unadaptable in primary healthcare centres. Recently, Fluorescence Resonance Energy Transfer (FRET) based immunosensors have found wide applicability in biomolecule detection. Among the evolving nanomaterials, Quantum dots (QDs) have been emerged as attractive donors in FRET based sensors for biomolecules. In the present work, we report a simple and sensitive fluorescence immunosensor for cTnI detection using Mercaptopropionic acid (MPA) capped Mn2+ doped ZnS QDs and MnO 2 nanosheet as the FRET couple. For the specific detection of cTnI antigen, we have coupled cTnI antibody on the surface of MPA capped Mn2+ doped ZnS QDs. cTnI can be detected linearly with a low Limit of Detection (LoD) of 0.05 ng/mL. Furthermore, the selectivity of the developed probe has also been evaluated in the presence of other potential interferants and other cardiac biomarkers. In real serum samples, good recovery percentage was obtained proving that the probe is adaptable for Point of care detection of cTnI. [ABSTRACT FROM AUTHOR]

Despite the very high specificity and simplicity, antibody-based assays require high costs and top-end preservation facilities to develop an efficient biosensor. We constructed "An antibody-free fluorescence probe for cardiac troponin -I," the 'gold standard' marker for diagnosing myocardial infarction. In the present work, positively charged green-emitting gold nanoclusters were synthesized through a one-pot microwave-mediated method, and the fluorescence response with heparin was studied. These heparin-conjugated gold nanoclusters were further utilized as a fluorescence probe for the non-enzymatic detection of cardiac troponin I. The linear detection of troponin with a low limit of detection of 0.1631 ng/mL was achieved with the probe. The challenging interfering perturbation of the co-existing biomolecules was evaluated, among which only glutathione showed an insignificant turn-on response within the biological limit. ● An antibody-free fluorescence platform for cardiac biomarker was explored. ● Non-enzymatic detection of cardiac troponin I within the clinically relevant concentration can be achieved within 15 min. ● Probe's fluorescence turn-on response has no significant interference from co-existing biomolecules. ● The probe is successful in sensing cTnI in the real biological matrix of human serum samples. [ABSTRACT FROM AUTHOR]

The present work is an attempt to investigate the heavy atom effect imparted by halide ions, especially iodide (I−) ions on the fluorescence behavior of carbon dots (CDs). Here two different types of CDs viz. nitrogen doped carbon dots (NCDs) from Citric Acid (CA) & Urea and Sulfur and nitrogen co-doped carbon dots (S,N-CDs) from CA & L-Cysteine were synthesized and the fluorescence of both CDs were quenched by heavy atom effect on adding potassium iodide (KI). The large difference in average lifetime was obtained in time-correlated single-photon counting (TCSPC) analysis suggests the dynamic quenching and heavy atom effect. [ABSTRACT FROM AUTHOR]

The direct detection of dopamine (DA) in human body fluids is a great challenge for medical diagnostics of neurological disorders like Parkinson's disease, Alzheimer's disease, senile dementia, and schizophrenia. In this work, a simple and turn off luminescence sensing of DA based on bovine serum albumin (BSA)-capped manganese-doped zinc sulphide quantum dots (Mn:ZnS/BSA QDs) is developed. The Mn:ZnS/BSA QDs were synthesized by a chemical co-precipitation method. Due to the special interaction of DA with BSA and metal ions, Mn:ZnS/BSA QDs can serve as an effective sensing platform for DA. The luminescence of Mn:ZnS/BSA QDs decreased linearly with increasing concentration of DA in the range from 6.6 to 50.6 nM. The limit of detection is 2.02 nM. The driving force for the luminescence quenching is partly provided by ground-state complex formation of QDs with DA. The photo-induced electron transfer from the conduction band of QDs to oxidized dopamine (quinone) also favors quenching. The Mn:ZnS/BSA QDs are barely interfered with by other competing biomolecules except catecholamine neurotransmitter like epinephrine. Moreover, this method is used in the analysis of DA-spiked human serum and human urine samples and good recovery percentages are found. To assess the utility of the developed sensor, paper strip assay was also successfully conducted. [ABSTRACT FROM AUTHOR]

Pancreatic cancer is one of the leading causes of cancer‐related death in the world due to non‐specific symptoms at early stages and late diagnosis. In this article, we report the use of nitrogen doped carbon nanodots (NCD) as fluorescent contrast agents for in vitro imaging of live pancreatic cancer cells. The surface of these NCDs was functionalised with tyrosine kinase inhibitor type anticancer drug named erlotinib. This targeting ligand enables specific in vitro targeting of epidermal growth factor receptor (EGFR) overexpressed human pancreatic cancer cell lines (PANC‐1). The receptor‐mediated fluorescence staining with targeted NCD was further tested by monitoring in vitro targeting in L929 mouse fibroblast cells with normal EGFR expression. The confocal fluorescence microscopic images show uniform fluorescence staining on PANC‐1 cells and a localised fluorescence staining on the central region of normal L929 cells. The fluorescence stability of targeted NCD even after conjugation with bovine serum albumin proved its potential for cellular imaging. [ABSTRACT FROM AUTHOR]