Comparison of the Watson formula and bioimpedance spectroscopy for measuring body volume and calculating kt/V in patients with peritoneal dialysis

CONCLUSION

There were significant differences between Vwat and Vbis and between Kt/Vwat and Kt/Vbis. Kt/Vwat may underestimate small-solute dialysis adequacy in most cases. Kt/Vbis instead of Kt/Vwat could be accounted for in creating individualized dialysis prescriptions if the patient has no obvious clinical symptoms.

Development of UV-Vis spectroscopy-based analysis method for determination of tin(IV) in epilobium parviflorum (hoary willowherb) tea using deep eutectic solvent based preconcentration

In this study, a UV-Vis Spectroscopy-based method was developed for the determination of tin(IV) in epilobium parviflorum tea samples after preconcentration. The preconcentration process was carried out using the liquid-liquid microextraction technique. Before starting the analysis, optimization studies were carried out for the variables likely to affect the experimental results. As a result of the analyzes performed under optimum conditions, the detection limit of our method was calculated as 16.83 μg/L. The percent relative standard deviation value was calculated as 1.25% (n = 8) and linearity was found in the range of 10-1000 μg/L. Recovery experiments were performed on epilobium parviflorum tea samples using the matrix matching method. As a result of the analyzes made on teas belonging to three different brands, recovery results ranging from 92 to 117% were obtained.

Machine learning-enabled high-throughput industry screening of edible oils

Long-term consumption of mixed fraudulent edible oils increases the risk of developing of chronic diseases which has been a threat to the public health globally. The complicated global supply-chain is making the industry malpractices had often gone undetected. In order to restore the confidence of consumers, traceability (and accountability) of every level in the supply chain is vital. In this work, we shown that machine learning (ML) assisted windowed spectroscopy (e.g., visible-band, infra-red band) produces high-throughput, non-destructive, and label-free authentication of edible oils (e.g., olive oils, sunflower oils), offers the feasibility for rapid analysis of large-scale industrial screening. We report achieving high-level of discriminant (AUC > 0.96) in the large-scale (n ≈ 11,500) of adulteration in olive oils. Notably, high clustering fidelity of 'spectral fingerprints' achieved created opportunity for (hypothesis-free) self-sustaining large database compilation which was never possible without machine learning. (137 words).

Unraveling the binding mechanism between soybean protein isolate and selected bioactive compounds

The present study was aimed to investigate the interactions between soybean protein isolate (SPI) with resveratrol (RESV) and lutein (LUT). The binding forces, molecular interactions and functional properties were explored by multi-spectroscopic analysis, molecular docking and functional property indexes between SPI and RESV/LUT. The RESV/LUT quenched SPI chromophore residues with static mechanism and the endothermic reaction. The SPI- RESV/LUT complexes were formed through hydrogen bond, electrostatic and hydrophobic interactions. Molecular docking confirmed van-der-Waals force as one of the important forces. The interaction of RESV/LUT led to SPI's secondary structure alterations with a decrease in α-helix and random coil and an increase in β-sheet and β-turns. RESV/LUT developed foaming and emulsifying properties of SPI and showed a significant decrease of the surface hydrophobicity with RESV/LUT concentrations increase attributed to SPI's partial unfolding. Our study exposed molecular mechanisms and confirmations to understand the interactions in protein- RESV/LUT complexes for protein industrial base promotion.

Infrared spectroscopy-based machine learning algorithms for rapid detection of Klebsiella pneumoniae isolated directly from patients' urine and determining its susceptibility to antibiotics

Among the most prevalent and detrimental bacteria causing urinary tract infections (UTIs) is Klebsiella (K.) pneumoniae. A rapid determination of its antibiotic susceptibility can enhance patient treatment and mitigate the spread of resistant strains. In this study, we assessed the viability of using infrared spectroscopy-based machine learning as a rapid and precise approach for detecting K. pneumoniae bacteria and determining its susceptibility to various antibiotics directly from a patient's urine sample. In this study, 2333 bacterial samples, including 636 K. pneumoniae were investigated using infrared micro-spectroscopy. The obtained spectra (27996spectra) were analyzed with XGBoost classifier, achieving a success rate exceeding 95 % for identifying K. pneumoniae. Moreover, this method allows for the simultaneous determination of K. pneumoniae susceptibility to various antibiotics with sensitivities ranging between 74 % and 81 % within approximately 40 min after receiving the patient's urine sample.

A one-class classification approach for authentication of specialty coffees by inductively coupled plasma mass spectroscopy (ICP-MS)

Due to the lucrative nature of specialty coffees, there have been instances of adulteration where low-cost materials are mixed in to increase the overall volume, resulting in illegal profit. A widely used and recommended approach to detect possible adulteration is the application of one-class classifiers (OCC), which only require information about the target class to build the models. Thus, this work aimed to identify adulterations in specialty coffees with low-quality coffee using multielement analysis determined by ICP-MS and to evaluate the performance of one-class classifiers (dd-SIMCA, OCRF, and OCPLS). Therefore, authentic specialty coffee samples were adulterated with low-quality coffee in 25 % to 75 % (w/w) proportions. Samples were subjected to acid decomposition for analysis by ICP-MS. OCPLS method presented the best performance to detect adulterations with low-quality coffee in specialty coffees, showing higher specificity (SPE = 100 %) and reliability rate (RLR = 94.3 %).

Does the age of milk affect its mid-infrared spectrum and predictions?

Milk of dairy species commonly undergo standardized official analyses, these that may require chemical preservation and transportation to a certified laboratory. In this context, storage duration is an important factor that can potential affect both milk chemical analyses and its mid-infrared spectrum. We analysed milk samples at different time points/ages to assess repeatability and reproducibility of mid-infrared predicted traits (e.g., fat and protein). Using spectral data, we also evaluated the ability of spectroscopy coupled with chemometrics to discriminate samples according to their age. Although the main components of milk remained consistently reproducible across age (days), changes in the spectrum due to sample aging and deterioration of the matrix were detectable. Using a discriminant analysis, we achieved a classification accuracy of 77% in validation. Predicting milk age using mid-infrared spectra is feasible, allowing for sample monitoring within circuits where maximum reliability is needed, e.g., bulk or individual milk samples for legal/official use or payment systems.

Characterization and classification of oleogels and edible oil using vibrational spectroscopy in tandem with one-class and multiclass chemometric methods

Oleogel represents a promising healthier alternative to act as a substitute for conventional fat in various food products. Oil selection is a crucial factor in determining the technological properties and applications of oleogels due to their distinct fatty acid composition, molecular weight, and thermal properties, as well as the presence of antioxidants and oxidative stability. Hence, the relevance of monitoring oleogel properties by non-destructive, eco-friendly, portable, fast, and effective techniques is a relevant task and constitutes an advance in the evaluation of oleogels quality. Thus, the present study aims to classify oleogels rapidly and reliably, without the use of chemicals, comparing two handheld near infrared (NIR) spectrometers and one portable Raman device. Furthermore, two different multivariate methods are compared for oleogel classification according to oil type. Three types of oleogels were prepared, containing 95 % oil (sunflower, soy, olive) and 5 % beeswax as a structuring agent, melted at 90 °C. Polarized light microscopy (PLM) images were acquired, and fatty acid composition, peroxide index and free fatty acid content were determined using official methods. A total of 240 oleogel and 92 oil spectra were obtained for each instrument. After spectra pretreatment, Principal Component Analysis (PCA) was performed, and two classification methods were investigated. The Data Driven - Soft Independent Modelling of Class Analogy (DD-SIMCA) and Partial Least Squares Discriminant Analysis (PLS-DA) models demonstrated 95 % to 100 % of accuracy for the external test set. In conclusion, the use of vibrational spectroscopy using handheld and portable instruments in tandem with chemometrics showed to be an efficient alternative for classifying oils and oleogels and could be extended to other food samples. Although the classification of vegetable oils by NIR is widely used and known, this work proposes the classification of different types of oil in oleogel matrices, which has not yet been explored in the literature.

A new ultrasound-assisted microextraction for elemental impurities determination in tablets by ICP-MS according to USP chapters 232 and 233

Along with the United States Pharmacopeia (USP) chapters 232 and 233 regarding elemental impurities in pharmaceutical products, new challenges have been imposed in terms of sample preparation procedures prior to inductively coupled plasma mass spectrometry analysis, considering the matrix complexities. As so, a new microextraction procedure assisted by ultrasound using a cup-horn sonoreactor, minimal reactants, and sample was proposed and validated according to USP. The procedure was optimized with samples of milled tablets and 3 different acid mixtures (HNO3, 3HNO3:1HCl, and 9HNO3:1HF) and it was compared with microwave-assisted acid digestion. In the validation step, recoveries ranging from 85 to 120 % and RSD below 10 % were obtained for 22 analytes (except Ag and Pt) with satisfactory linearity and good sensitivity. The method was then applied for 37 samples of antidepressants, which presented trace levels of As, Ba, Cd, Co, Cr, Cu, Ni, Pb, Pd, Sn, and V.

Quantification of [99Tc]TcO4- in urine by means of anion-exchange chromatography-aerosol desolvation nebulization-inductively coupled plasma-mass spectrometry

To sensitively determine 99Tc, a new method for internal quantification of its most common and stable species, [99Tc]Tc O 4 - , was developed. Anion-exchange chromatography (IC) was coupled to inductively coupled plasma-mass spectrometry (ICP-MS) and equipped with an aerosol desolvation system to provide enhanced detection power. Due to a lack of commercial Tc standards, an isotope dilution-like approach using a Ru spike and called isobaric dilution analysis (IBDA) was used for internal quantification of 99Tc. This approach required knowledge of the sensitivities of 99Ru and 99Tc in ICP-MS. The latter was determined using an in-house prepared standard manufactured from decayed medical 99mTc-generator eluates. This standard was cleaned and preconcentrated using extraction chromatography with TEVA resin and quantified via total reflection X-ray fluorescence (TXRF) analysis. IC coupled to ICP-MS enabled to separate, detect and quantify [99Tc]Tc O 4 - as most stable Tc species in complex environments, which was demonstrated in a proof of concept. We quantified this species in untreated and undiluted raw urine collected from a patient, who previously underwent scintigraphy with a 99mTc-tracer, and determined a concentration of 19.6 ± 0.5 ng L-1. The developed method has a high utility to characterize a range of Tc-based radiopharmaceuticals, to determine concentrations, purity, and degradation products in complex samples without the need to assess activity parameters of 99(m)Tc.

An overview of preconcentration techniques combined with inductively coupled plasma mass spectrometry for trace element determination in biological studies

In the last decades, the determination of trace elements in biological materials has emerged as an important area of study because of its relevance to human health and the environment. Inductively coupled plasma mass spectrometry (ICP-MS) has proven to be a powerful tool for trace element analysis, owing to its high sensitivity and ability to determine several elements in a single measurement. However, given the complex nature of biological matrices and the presence of elements, most of them at ultratrace levels, it becomes crucial to complement ICP-MS with preconcentration techniques to increase the sensitivity and selectivity of analytical methods. This article presents an exhaustive overview of liquid- and solid-phase preconcentration techniques used in combination with ICP-MS for trace element determination in different biological samples from 2000 to the present. An in-depth discussion of the advances on the application of state-of-the-art solvents and materials in trace element extraction and preconcentration is presented. Special attention is given to different strategies for elemental speciation analysis, employing both chromatographic and non-chromatographic techniques. The role of automation in these methodologies is also described. Finally, future trends and challenges related to this topic are discussed.

3D polarization-interference holographic histology for wavelet-based differentiation of the polycrystalline component of biological tissues with different necrotic states. Forensic applications

Significance

The interference-holographic method of phase scanning of fields of scattered laser radiation is proposed. The effectiveness of this method for the selection of variously dispersed components is demonstrated. This method made it possible to obtain polarization maps of biological tissues at a high level of depolarized background. The scale-selective analysis of such maps was used to determine necrotic changes in the optically anisotropic architectonics of biological tissues.

Objective

Development and experimental approbation of layered phase polarimetry of repeatedly scattered fields in diffuse layers of biological tissues. Application of scale-selective processing of the found coordinate distributions of polarization states in various phase sections of object fields. Determination of criteria (markers) for histological differential diagnosis of the causes of necrotic changes in optical anisotropy of biological tissues.

Approach

We used a synthesis of three instrumental and analytical methods. Polarization-interference registration of laser radiation scattered by a sample of biological tissue. Digital holographic reconstruction and layered phase scanning of distributions of complex amplitudes of the object field. Analytical determination of polarization maps of various phase cross-sections of repeatedly scattered radiation. Application of wavelet analysis of the distributions of polarization states in the phase plane of a single scattered component of an object field. Determination of criteria (markers) for differential diagnosis of necrotic changes in biological tissues with different morphological structure. Two cases are considered. The first case is the myocardium of those who died as a result of coronary heart disease and acute coronary insufficiency. The second case is lung tissue samples of deceased with bronchial asthma and fibrosis.

Results

A method of polarization-interference mapping of diffuse object fields of biological tissues has been developed and experimentally implemented. With the help of digital holographic reconstruction of the distributions of complex amplitudes, polarization maps in various phase sections of a diffuse object field are found. The wavelet analysis of azimuth and ellipticity distributions of polarization in the phase plane of a single scattered component of laser radiation is used. Scenarios for changing the amplitude of the wavelet coefficients for different scales of the scanning salt-like MHAT function are determined. Statistical moments of the first to fourth orders are determined for the distributions of the amplitudes of the wavelet coefficients of the azimuth maps and the ellipticity of polarization. As a result, diagnostic markers of necrotic changes in the myocardium and lung tissue were determined. The statistical criteria found are the basis for determining the accuracy of their differential diagnosis of various necrotic states of biological tissues.

Conclusions

Necrotic changes caused by "coronary artery disease-acute coronary insufficiency" and "asthma-pulmonary fibrosis" were demonstrated by the method of wavelet differentiation with polarization interference with excellent accuracy.

Determination of Trace, Micro and Macro Elemental Concentration of Eritrean Honeys

In this study macro, micro and trace elemental concentrations were measured in Eritrean acacia honey samples by Inductively Coupled Plasma Optical Emission Spectrometry (Al, B, C, K, Mg, Na, P and S) and Inductively Coupled Plasma Mass Spectrometry (As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr and Zn). The concentration of essential elements in the examined Eritrean acacia honeys decreased in the following order: K > P > Ca > Mg > Fe > Zn > Mn > Cu > Sr > Mo. Independent samples T test was used to determine the statistically verified differences between the two regions, but there was none; however there were remarkable differences among the measured element contents of specific honey samples. Elemental concentrations of Eritrean honeys are influenced by the characteristics of the collecting area (e.g. elevation, agricultural activities, water resources).Our samples showed low essential elemental concentration; therefore the consumption of these honeys does not contribute significantly to the nutrition reference value (NRV) (around 1% of NRV). Toxic elemental concentrations were also low; thus the calculated estimated daily intakes were much lower than the tolerable daily intakes. Consumption of these honeys presents no risk for the human body.

Design of a dual Ir-Eu tag for fluorescent visualization and ICP-MS quantification of SIRPα and its host cells

With the expansion of ICP-MS application into the field of bioanalysis, there is an urgent need for novel element tags today. Here, we report the design of a dual-element Ir-Eu tag, opening the door to simultaneous fluorescent imaging and ICP-MS quantification. The ratio of 153Eu/193Ir may serve as a precision control of the labeling process, allowing internal validation of the quantitative results obtained. As for SIRPα and its host cell analysis exemplified here, the Ir-Eu tag demonstrated superior figures of ICP-MS quantification with the LOD (3σ) down to 0.5 (153Eu) and 1.1 (193Ir) pM SIRPα and 220 (153Eu) and 830 (193Ir) RAW264.7 cells more than 130 times more sensitive compared with the LOD (3σ) of 65.2 pM SIRPα at 612 nm using fluorometry. Not limited to these demonstrations, we believe that the design ideas of the dual Ir-Eu tags should be applicable to various cases of bioanalysis when dual optical profiling and ICP-MS quantification are indispensable.

Enhancing biomarker detection sensitivity through tag-laser induced breakdown spectroscopy with NELIBS

Nanoparticle-enhanced laser-induced breakdown spectroscopy and Tag-LIBS are two approaches that have been shown to significantly enhance LIBS sensitivity and specificity. In an effort to combine both of these approaches, we have initiated a study on the effect of the presence of Silver nanoparticle concentrations on Europium (Eu) and Ytterbium (Yb) LIBS signals. These elements are part of metal-loaded polymers conjugated to antibodies. We observe a signal enhancement of the emission lines of about 10 and 12 times for the Europium and Ytterbium lines. This study shows that Europium and Ytterbium are enhanced differently; Europium shows enhancement for both neutral and ionized species while the Ytterbium shows enhancement only for ionized species. Additionally, we found that NPs at 0.1 mg/mL and 0.05 mg/mL achieved maximum enhancement for Eu and Yb, respectively. Based on our findings, the temperature and electron density of Eu and Yb are not significantly different for NPs concentrations, but the total signal intensity is significantly higher for optimum NP concentrations for both Eu and Yb.

Discrimination of vocal folds lesions by multiclass classification using autofluorescence spectroscopy: An ex vivo study

BACKGROUND

Autofluorescence spectroscopy is effective for noninvasive detection but underutilized in tissue with various pathology analyses. This study evaluates whether AFS can be used to discriminate between different types of laryngeal lesions in view of assisting in vocal fold surgery and preoperative investigations.

METHODS

A total of 1308 spectra were recorded from 29 vocal fold samples obtained from 23 patients. Multiclass analysis was performed on the spectral data, categorizing lesions into normal, benign, dysplastic, or carcinoma.

RESULTS

Through an appropriate selection of spectral components and a cascading classification approach based on artificial neural networks, a classification rate of 97% was achieved for each lesion class, compared to 52% using autofluorescence intensity.

CONCLUSIONS

The ex vivo study demonstrates the effectiveness of AFS combined with multivariate analysis for accurate classification of vocal fold lesions. Comprehensive analysis of spectral data significantly improves classification accuracy, such as distinguishing malignant from precancerous or benign lesions.

Application of microscopy and spectroscopy in investigating anti-cancer potential of Achyranthes aspera L. leaves

The genus Achyranthes belong to the family Amaranthaceae which constitutes an important group of herbs and shrubs with immense medicinal value. The present research work was conducted to investigate the anticancer potential of Achyranthes aspera L. leaves by focusing on the antioxidant, aniproliferative and antimitotic activities of leaf extracts. Plant extraction was carried out by soxhelt method with different solvents. Phytochemical characterization of the plants extracts using chemical methods identified the presence of cardiac glycosides, saponins, coumarins, proteins, tannins, flavonoids and triterpenes. Alkaloid was present in methanolic and ethanolic extract. High performance liquid chromatography showed presence of different concentration of myricetin, quercetin and kaempferol in different extracts with the highest concentration of myricetin (84.53 μg/mL) in n-butanolic extract. The extracts were then tested for antioxidant activity using 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging assay by spectrophotometric method. In DPPH radical scavenging assay, antioxidant activity of A. aspera ranged between 79.78 ± 0.034% and 58.63 ± 0.069%. Highest antioxidant activity was observed for methanolic extract and lowest for acetone. Antimitotic activity was determined by using Allium cepa assay in which microscopic investigation was carried out to observe normal and abnormal phases of mitosis. In this assay, n-butanolic extract had highest antimitotic activity with minimum mitotic index at 2 mg/mL (57 ± 0.0351%). The plant extracts also caused chromosomal and mitotic aberrations which were clearly observed under 40× and 100× magnification of compound microscope. Antiproliferative activity was determined by using yeast cell model in which light microscope with hemocytometer was used for cell counting. In case of Antiproliferative activity, the ethyl acetate extract of A. aspera had highest antiproliferative activity with lowest cell viability (22.14 ± 0.076%) at highest extract concentration (2 mg/mL) while methanol extract of A. aspera had highest antiproliferative activity with lower cell viability (24.24 ± 0.057%) at lowest extract concentration (0.25 mg/mL). The results of the study indicated that the leaves extract of A. aspera have strong potential to be used as a source of anti-cancer agent. RESEARCH HIGHLIGHTS: Achyranthes aspera L. leaves have various phytochemicals which contribute to its medicinal properties Various extracts of the leaves of A. aspera L. possess antioxidant, antimitotic and antiproliferative potential The results of the study indicated that the leaves extract of A. aspera have strong potential to be used as a source of anti-cancer agent.

Label-free detection of biomolecules using inductively coupled plasma mass spectrometry (ICP-MS)

Bioassays using inductively coupled plasma mass spectrometry (ICP-MS) have gained increasing attention because of the high sensitivity of ICP-MS and the various strategies of labeling biomolecules with detectable metal tags. The classic strategy to tag the target biomolecules is through direct antibody-antigen interaction and DNA hybridization, and requires the separation of the bound from the unbound tags. Label-free ICP-MS techniques for biomolecular assays do not require direct labeling: they generate detectable metal ions indirectly from specific biomolecular reactions, such as enzymatic cleavage. Here, we highlight the development of three main strategies of label-free ICP-MS assays for biomolecules: (1) enzymatic cleavage of metal-labeled substrates, (2) release of immobilized metal ions from the DNA backbone, and (3) nucleic acid amplification-assisted aggregation and release of metal tags to achieve amplified detection. We briefly describe the fundamental basis of these label-free ICP-MS assays and discuss the benefits and drawbacks of various designs. Future research is needed to reduce non-specific adsorption and minimize background and interference. Analytical innovations are also required to confront challenges faced by in vivo applications.

Investigation of elemental composition in red teff grains using inductively coupled plasma optical emission spectroscopy (ICP OES), Sire District, Arsi zone, Ethiopia

BACKGROUND

Minerals are important not only for better plant growth and development but also for human and animal nutrition. It is known that east and west Gojam in the Amhara region and east and west Shoa areas in the Oromia region Ethiopia's most teff growing areas. However, there is no information on the mineral content and nutritional worth of Teff Sire district, Arsi zone, Ethiopia. Since ICP OES is a powerful technique to examine elemental compositions even in lower concentration, it is used in this work to investigate the elemental composition of red teff samples.

METHODS

The elemental compositions of red Teff grain samples were determined using ICP-OES from three sites: S1, S2, and S3 of Sire district, Arsi zone, Ethiopia. Wet digestion of the teff samples was carried out by weighing 0.5 g red teff sample and digested with 8 ml HNO3 and 2 ml H2O2 (30%) for 3:00 h at a temperature of 100℃ on hot plate. The investigations of method validation, limit of detection and limit of quantification were also carried out.

RESULTS

The average amount of elements in red teff sample obtained as 172-280 mg/kg Fe, 13-76 mg/kg Mn, 8.2-8.5 mg/kg Cu, 24-26 mg/kg Zn, and toxic trace elements 0.12-0.29 mg/kg Pb and 0.15-0.22 mg/kg Cd. The limit of detection found in ranges from 0.21 mg Kg-1 to 10.44 mg Kg-1 whereas quantification limit resulted in 0.7 mg Kg-1 to 34.8 mg Kg-1 for the metals under consideration. The method was validated by its linear range in the concentration range of 0.028-1.4 ppm or 0.056-2.8 ppm and excellent recovery result was achieved in the range of 90-120%.

CONCLUSION

This study aimed to investigate the mineral content in red teff cultivated in Ethiopia specifically Arsi zone by using ICP OES. From the obtained results, Iron was the first abundant essential element in red teff compared to Mn, Cu and Zn. The level of trace elements: Cd and Pb in the samples slightly above the acceptable limit, possibly due to agricultural practices like usage of fertilizers, pesticides, and other industrial products. Overall, this red teff elemental composition information contributes to the nutrition database and food safety in Ethiopia and beyond.

Critical evaluation of the potential of ICP-MS-based systems in toxicological studies of metallic nanoparticles

The extensive application of metallic nanoparticles (NPs) in several fields has significantly impacted our daily lives. Nonetheless, uncertainties persist regarding the toxicity and potential risks associated with the vast number of NPs entering the environment and human bodies, so the performance of toxicological studies are highly demanded. While traditional assays focus primarily on the effects, the comprehension of the underlying processes requires innovative analytical approaches that can detect, characterize, and quantify NPs in complex biological matrices. Among the available alternatives to achieve this information, mass spectrometry, and more concretely, inductively coupled plasma mass spectrometry (ICP-MS), has emerged as an appealing option. This work critically reviews the valuable contribution of ICP-MS-based techniques to investigate NP toxicity and their transformations during in vitro and in vivo toxicological assays. Various ICP-MS modalities, such as total elemental analysis, single particle or single-cell modes, and coupling with separation techniques, as well as the potential of laser ablation as a spatially resolved sample introduction approach, are explored and discussed. Moreover, this review addresses limitations, novel trends, and perspectives in the field of nanotoxicology, particularly concerning NP internalization and pathways. These processes encompass cellular uptake and quantification, localization, translocation to other cell compartments, and biological transformations. By leveraging the capabilities of ICP-MS, researchers can gain deeper insights into the behaviour and effects of NPs, which can pave the way for safer and more responsible use of these materials.

Exploring the evolution of circular polarized light backscattered from turbid tissue-like disperse medium utilizing generalized Monte Carlo modeling approach with a combined use of Jones and Stokes-Mueller formalisms

Significance

Phase retardation of circularly polarized light (CPL), backscattered by biological tissue, is used extensively for quantitative evaluation of cervical intraepithelial neoplasia, presence of senile Alzheimer's plaques, and characterization of biotissues with optical anisotropy. The Stokes polarimetry and Mueller matrix approaches demonstrate high potential in definitive non-invasive cancer diagnosis and tissue characterization. The ultimate understanding of CPL interaction with tissues is essential for advancing medical diagnostics, optical imaging, therapeutic applications, and the development of optical instruments and devices.

Aim

We investigate propagation of CPL within turbid tissue-like scattering medium utilizing a combination of Jones and Stokes-Mueller formalisms in a Monte Carlo (MC) modeling approach. We explore the fundamentals of CPL memory effect and depolarization formation.

Approach

The generalized MC computational approach developed for polarization tracking within turbid tissue-like scattering medium is based on the iterative solution of the Bethe-Salpeter equation. The approach handles helicity response of CPL scattered in turbid medium and provides explicit expressions for assessment of its polarization state.

Results

Evolution of CPL backscattered by tissue-like medium at different conditions of observation in terms of source-detector configuration is assessed quantitatively. The depolarization of light is presented in terms of the coherence matrix and Stokes-Mueller formalism. The obtained results reveal the origins of the helicity flip of CPL depending on the source-detector configuration and the properties of the medium and are in a good agreement with the experiment.

Conclusions

By integrating Jones and Stokes-Mueller formalisms, the combined MC approach allows for a more complete representation of polarization effects in complex optical systems. The developed model is suitable to imitate propagation of the light beams of different shape and profile, including Gaussian, Bessel, Hermite-Gaussian, and Laguerre-Gaussian beams, within tissue-like medium. Diverse configuration of the experimental conditions, coherent properties of light, and peculiarities of polarization can be also taken into account.

Metabolic Imaging of Acute Ischemic Stroke (PET, 1Hydrogen Spectroscopy, 17Oxygen Imaging, 23Sodium MRI, pH Imaging)

Acute stroke imaging plays a vital and time-sensitive role in therapeutic decision-making. Current clinical workflows widely use computed tomography (CT) and magnetic resonance (MR) techniques including CT and MR perfusion to estimate the volume of ischemic penumbra at risk for infarction without acute intervention. The use of imaging techniques aimed toward evaluating the metabolic derangements underlying a developing infarct may provide additional information for differentiating the penumbra from benign oligemia and infarct core. The authors review several modalities of metabolic imaging including PET, hydrogen and oxygen spectroscopy, sodium MRI, and pH-weighted MRI.

Spectroscopy and absolute quantum efficiency of near-infrared electrochemiluminescence for a macrocyclic palladium complex

Electrochemiluminescence (ECL) is widely applied as a reliable tool in clinical diagnosis, including immunoassays, cancer biomarker detection, etc. Metal complexes with emission in the near-infrared (NIR) range possess distinct features such as high transmission and minimal tissue auto-absorption, making them versatile for applications in biosensing and other fields. Through ECL spectral studies of an O-linked nonaromatic benzitripyrrin (C^N^N^N) macrocyclic palladium complex (Pd1) with multiple pyrrole structures, we observed emission peaks from the Qx(0,0) and its vibronic Qx(0,1) bands during both photoluminescence (PL) and ECL. Notably, the emission from the Qx(0,1) band was significantly enhanced in the ECL spectrum, demonstrating higher selectivity for near-infrared light at 743 nm. In the ECL annihilation pathway, the appearance of ECL signals showed a strong correlation with the redox processes of the tri-pyrrin structure, revealing a cyclic tri-pyrrin ligand-centered nature with contributions from the metal center. Upon the introduction of tripropylamine (TPrA) and benzoyl peroxide (BPO) coreactants, the ECL signals exhibited enhancements ranging from several hundred to tens of times. Various reaction routes within different coreactant systems are extensively discussed. Additionally, the absolute quantum efficiencies of the Pd1/TPrA coreactant system were determined, showing efficiencies of 0.0032% ± 0.0005% and 0.000074% ± 0.000016% during pulsing and CV scan processes, respectively. This work addresses gaps in the study of palladacycle complexes in ECL and provides insights into the design of NIR luminescent structures that contribute to the fast screening and deep tissue penetration bioimaging techniques.

Mueller matrix-based characterization of cervical tissue sections: a quantitative comparison of polar and differential decomposition methods

Significance

Quantitative optical polarimetry has received considerable recent attention owing to its potential for being an efficient diagnosis and characterizing tool with potential applications in biomedical research and various other disciplines. In this regard, it is crucial to validate various Mueller matrix (MM) decomposition methods, which are utilized to extract and quantify the intrinsic individual polarization anisotropy properties of various complex optical media.

Aim

To quantitatively compare the performance of both polar and differential MM decomposition methods for probing the structural and morphological changes in complex optical media through analyzing their intrinsic individual polarization parameters, which are extracted using the respective decomposition algorithms. We also intend to utilize the decomposition-derived anisotropy parameters to distinguish among the cervical tissues with different grades of cervical intraepithelial neoplasia (CIN) and to characterize the healing efficiency of an organic crystal.

Approach

Polarization MM of the cervical tissues with different grades of CIN and the different stages of the self-healing crystal are recorded with a home-built MM imaging setup in the transmission detection geometry with a spatial resolution of ≈ 400    nm . The measured MMs are then processed with both the polar and differential MM decomposition methods to extract the individual polarization parameters of the respective samples. The derived polarization parameters are further analyzed to validate and compare the performance of both the MM decomposition methods for probing and characterizing the structural changes in the respective investigated optical media through their decomposition-derived intrinsic individual polarization properties.

Results

Pronounced differences in the decomposed-derived polarization anisotropy parameters are observed for cervical tissue sections with different grades of CIN. While a significant increase in the depolarization parameter ( Δ ) is obtained with the increment of CIN stages for both the polar [Δ = 0.32 for CIN grade one (CIN-I) and Δ = 0.53 for CIN grade two (CIN-II))] and differential (Δ = 0.35 for CIN-I and Δ = 0.56 for CIN-II) decomposition methods, a trend reversal is seen for the linear diattenuation parameter ( d L ) , indicating the structural distortion in the cervical morphology due to the CIN disease. More importantly, with the differential decomposition algorithm, the magnitude of the derived d L parameter decreases from 0.26 to 0.19 with the progression of CIN, which was not being probed by the polar decomposition method.

Conclusion

Our results demonstrate that the differential decomposition of MM holds certain advantages over the polar decomposition method to characterize and probe the structural changes in the cervical tissues with different grades of CIN. Although the quantified individual polarization parameters obtained through both the MM decomposition methods can be used as useful metrics to characterize various optical media, in case of complex turbid media such as biological tissues, incorporation of the differential decomposition technique may yield more efficient information. Also, the study highlights the utilization of MM polarimetry with an appropriate decomposition technique as an efficient diagnostic and characterizing tool in the realm of biomedical clinical research, and various other disciplines.

Microwave-induced combustion for further determination of potentially toxic elements in honey by ICP-MS

Microwave-induced combustion (MIC) was proposed in this study for honey decomposition aiming for As, Cd, Hg, and Pb determination by inductively coupled plasma mass spectrometry (ICP-MS). Sample mass (up to 1.0 g), absorbing solution (0.5 to 14.4 mol L-1 HNO3, and H2O), heating program, and combustion aids were evaluated. The Eurachem guidelines were used for method validation. The proposed method enabled combustion of a high sample mass (0.8 g of honey, with 0.4 g of microcrystalline cellulose and 100 µL of 6 mol L-1 NH4NO3) using 6 mL of an absorbing solution consisting of 1 mol L-1 HNO3, which resulted in low residual carbon in solution (< 25 mg L-1). Honey samples from different geographical origins were analyzed. Results showed no significant difference in comparison to other two microwave decomposition methods, based on microwave-assisted wet digestion with single reaction chamber (MAWD-SRC) and microwave-assisted wet digestion (MAWD). Standard addition experiments resulted in recoveries higher than 98%. The limits of detection ranged from 1.10 (As) to 4.60 ng g-1 (Pb). In addition to using only diluted reagents and resulting in digests virtually free of interferences, the proposed method was faster (< 30 min) than most of those presented in the literature.

Breath of Health: spectroscopy-based breath test for the detection of SARS-CoV-2

BACKGROUND

Nucleic acid amplification tests (NAAT) are considered the gold standard for COVID-19 diagnosis. These tests require professional manpower and equipment, long processing and swab sampling which is unpleasant to the patients. Several volatile organic compounds (VOCs) have been identified in the breath of COVID-19 patients. Detection of these VOCs using a breath test could help rapidly identify COVID-19 patients.

OBJECTIVE

Assess the accuracy of 'Breath of Health' (BOH) COVID-19 Fourier-transform infra-red (FTIR) Spectroscopy-based breath test.

METHODS

Breath samples from patients with or without symptoms suggestive for COVID-19 who had NAAT results were collected using Tedlar bags and were blindly analysed using BOH FTIR spectroscopy. BOH Measures several VOCs simultaneously and differentiating positive and negative results. BOH results were compared to NAAT results as gold standard.

RESULTS

Breath samples from 531 patients were analysed. The sensitivity of BOH breath test was found to be 79.5% and specificity was 87.2%. Positive predictive value (PPV) was 74.7% and negative predictive value (NPV) 90.0%. Calculated accuracy rate was 84.8% and area under the curve 0.834. Subgroup analysis revealed that the NPV of patients without respiratory symptoms was superior over the NPV of symptomatic patients (94.7% vs 80.7%, P-value < 0.0001) and PPV of patients with respiratory symptoms outranks the PPV of individuals without symptoms (85.3% vs 69.2%, P-value 0.0196).

CONCLUSION

We found BOH COVID-19 breath test to be a patient-friendly, rapid, non-invasive diagnostic test with high accuracy rate and NPV that could efficiently rule out COVID-19 especially among individuals with low pre-test probability.

Assessment of radio-activation using spectroscopy in medical linear accelerators

In radiotherapy, when photon energy exceeding 8 MV is utilized, photoneutrons can activate the components within the gantry of the linear accelerator (linac). At the end of the linac's lifecycle, radiation workers are tasked with its dismantling and disposal, potentially exposing them to unintentional radiation. This study aims to identify and measure the radioisotopes generated by this activation through spectroscopy, and to evaluate the effective dose rate. We selected nine medical linacs, considering various factors such as manufacturer (Siemens, Varian, and Elekta), model, energy, period of operation, and workload. We identified the radionuclides in the linac head by employing an in situ high-purity germanium (HPGe) detector. Spectroscopy and dose-rate measurements were conducted post-shutdown. We also measured the dose rates at the beam-exit window following irradiation with 10 MV and 15 MV photon beams. As a result of the spectroscopy, we identified approximately 20 nuclides including those with half-lives of 100 days or longer, such as 54Mn, 60Co, 65Zn, 122Sb, and 198Au. The dose rate measurements after 10 MV irradiation decreased to the background level in 10 min. By contrast, on 15 MV irradiation, the dose rate was 628 nSv/h after 10 min and decreased to 268 nSv/h after 1.5 hours. It was confirmed that the difference in the level of radiation and the type of nuclide depends on the period of use, energy, and workload. However, the type of nuclide does not differ significantly between the linacs. It is necessary to propose appropriate guidelines for the safety of workers, and disposal/move-install should be planned while taking into consideration the equipment's energy usage rate.

Plasticizer concentration effect on films and coatings based on poly(vinyl alcohol) and cationic starch blends

Films based on poly(vinyl alcohol) (PVA) and cationic starch (CS) were combined with different percentages of sorbitol (S; 15.0, 22.5, and 30.0% w v-1) to assess the effect of plasticizer on the films. Spectroscopic analyses confirmed the interaction between them. However, micrographs indicated the formation of sorbitol crystals on the surface of the films, especially at higher sorbitol concentrations. The blends presented low water vapor transmission rate values, reaching (7.703 ± 0.000) g h-1 m-2 (PVA75CS25S15), and low solubility values for the films containing higher CS amounts. The lack of statistical differences in most parameters suggests that no significant gain comes from increasing the amount of sorbitol at percentages higher than 15%. As a coating, the blend PVA75CS25S15 successfully decreased the loss of moisture content in acerolas by 1.15 times (compared to the control), confirming the suitability of this matrix as a fruit coating.

Quantitative determination of potential genotoxic impurities in metformin hydrochloride and empagliflozin tablets through ultra-performance liquid chromatographymass spectrometry

An increasing number of drug research institutions consider genotoxic impurity research a core task in drug research and development. Peroxides in drugs may directly or indirectly attack and damage cell DNA, posing a potential carcinogenic risk to the human body. Currently, the literature only studies hydroperoxide impurities, and benzyl peroxide has not been studied yet. In this study, an effective method for ultra-performance liquid chromatographymass spectrometry (UPLCMS/MS) was established and verified to detect and quantify the potential genotoxic impurity (PGI), empagliflozin benzyl peroxide, in metformin-empagliflozin combination formulations, which has not been reported thus far. A Waters ACQUITY UPLC HSS T3 (3.0 ×100 mm, 1.8 µm) column was used to achieve chromatographic separation with gradient elution. The mass spectrometry conditions were optimized using electrospray ionization in the negative mode. Following the International Conference of Harmonization (ICH) guidelines, this methodology can quantify PGIs at 1.35 ng/mL (5.4 ppm) in samples. This validated method exhibited good linearity over a concentration range of 5.4 to 36 ppm, and the accuracy of this method was in the range of 83.2-95.0% for empagliflozin benzyl peroxide. This approach fills the gap in the detection method for benzyl peroxide impurities in metformin hydrochloride and empagliflozin tablets, providing technical support for the quality control of the drug.

Label-free quantification of gold nanoparticles at the single-cell level using a multi-column convolutional neural network (MC-CNN)

Gold nanoparticles (AuNPs) are extensively used in cellular imaging, single-particle tracking, disease diagnosis, studying membrane protein interaction, and drug delivery. Understanding the dynamics of AuNP uptake in live cells is crucial for optimizing their efficacy and safety. Traditional manual methods for quantifying AuNP uptake are time-consuming and subjective, limiting their scalability and accuracy. The available fluorescence-based techniques are limited to photobleaching and photoblinking. Optical microscopy techniques are limited by diffraction limits. Electron microscopy-based imaging techniques are destructive and unsuitable for live cell imaging. Furthermore, the resulting images may contain hundreds of particles with varied intensities, blurring, and substantial occlusion, making it difficult to manually quantify AuNP uptake. To overcome this issue and measure AuNP uptake by live cells, we annotated a dataset of dark-field images of 50 nanometer-radius AuNPs at different incubation durations. Then, to count the number of particles present in a cell, we created a customized multi-column convolutional neural network (MC-CNN). The customized MC-CNN outperformed typical particle counting architectures when compared to spectroscopy-based counting. This will allow researchers to gain a better understanding of AuNP behavior and interactions with cells, paving the way for advancements in nanomedicine, drug delivery, and biomedical research. The code for this paper is available at the following link: https://github.com/Namerlight/LabelFree_AuNP_Quantification.

Correlating Structure with Spectroscopy in Ascorbate Peroxidase Compound II

Structural and spectroscopic investigations of compound II in ascorbate peroxidase (APX) have yielded conflicting conclusions regarding the protonation state of the crucial Fe(IV) intermediate. Neutron diffraction and crystallographic data support an iron(IV)-hydroxo formulation, whereas Mössbauer, X-ray absorption (XAS), and nuclear resonance vibrational spectroscopy (NRVS) studies appear consistent with an iron(IV)-oxo species. Here we examine APX with spectroscopy-oriented QM/MM calculations and extensive exploration of the conformational space for both possible formulations of compound II. We establish that irrespective of variations in the orientation of a vicinal arginine residue and potential reorganization of proximal water molecules and hydrogen bonding, the Fe-O distances for the oxo and hydroxo forms consistently fall within distinct, narrow, and nonoverlapping ranges. The accuracy of geometric parameters is validated by coupled-cluster calculations with the domain-based local pair natural orbital approach, DLPNO-CCSD(T). QM/MM calculations of spectroscopic properties are conducted for all structural variants, encompassing Mössbauer, optical, X-ray absorption, and X-ray emission spectroscopies and NRVS. All spectroscopic observations can be assigned uniquely to an Fe(IV)═O form. A terminal hydroxy group cannot be reconciled with the spectroscopic data. Under no conditions can the Fe(IV)═O distance be sufficiently elongated to approach the crystallographically reported Fe-O distance. The latter is consistent only with a hydroxo species, either Fe(IV) or Fe(III). Our findings strongly support the Fe(IV)═O formulation of APX-II and highlight unresolved discrepancies in the nature of samples used across different experimental studies.

Augmenting authenticity for non-invasive in vivo detection of random blood glucose with photoacoustic spectroscopy using Kernel-based ridge regression

Photoacoustic Spectroscopy (PAS) is a potential method for the noninvasive detection of blood glucose. However random blood glucose testing can help to diagnose diabetes at an early stage and is crucial for managing and preventing complications with diabetes. In order to improve the diagnosis, control, and treatment of Diabetes Mellitus, an appropriate approach of noninvasive random blood glucose is required for glucose monitoring. A polynomial kernel-based ridge regression is proposed in this paper to detect random blood glucose accurately using PAS. Additionally, we explored the impact of the biological parameter BMI on the regulation of blood glucose, as it serves as the primary source of energy for the body's cells. The kernel function plays a pivotal role in kernel ridge regression as it enables the algorithm to capture intricate non-linear associations between input and output variables. Using a Pulsed Laser source with a wavelength of 905 nm, a noninvasive portable device has been developed to collect the Photoacoustic (PA) signal from a finger. A collection of 105 individual random blood glucose samples was obtained and their accuracy was assessed using three metrics: Root Mean Square Error (RMSE), Mean Absolute Difference (MAD), and Mean Absolute Relative Difference (MARD). The respective values for these metrics were found to be 10.94 (mg/dl), 10.15 (mg/dl), and 8.86%. The performance of the readings was evaluated through Clarke Error Grid Analysis and Bland Altman Plot, demonstrating that the obtained readings outperformed the previously reported state-of-the-art approaches. To conclude the proposed IoT-based PAS random blood glucose monitoring system using kernel-based ridge regression is reported for the first time with more accuracy.

Molecular Structure of Salicylic Acid and Its Hydrates: A Rotational Spectroscopy Study

We present a study of salicylic acid and its hydrates, with up to four water molecules, done by employing chirped-pulse Fourier transform microwave spectroscopy. We employed the spectral data set of the parent, 13C, and 2H isotopologues to determine the molecular structure and characterize the intra- and intermolecular interactions of salicylic acid and its monohydrate. Complementary theoretical calculations were done to support the analysis of the experimental results. For the monomer, we analyzed structural properties, such as the angular-group-induced bond alternation (AGIBA) effect. In the microsolvates, we analyzed their main structural features dominated by the interaction of water with the carboxylic acid group. This work contributes to seeding information on how water molecules accumulate around this group. Moreover, we discussed the role of cooperative effects further stabilizing the observed inter- and intramolecular hydrogen bond interactions.

Intermolecular hydrogen bonding in DNA base pairs interacting with different numbers of bare and hydrated Li+: NBO, QTAIM, and computational spectroscopic studies

In this study, the effect of different numbers of Li+ interacting with various sites of DNA base pairs (adenine-thymine (AT) and cytosine-guanine (GC)) on the base pair structures, the strength of hydrogen bonding between the bases, and spectroscopic properties (IR and absorption spectra) of the base pairs was investigated. Two quantum computational analyses, the natural bonding orbitals (NBO) and the quantum theory of atoms in molecules (QTAIM), were used to follow the change in the strength of hydrogen bonds between the bases in each pair. The type of base pair's site interacting with Li+ showed different effects on the change in the strength of the hydrogen bonds between the bases. The IR and absorption spectra of the lithiated base pairs were calculated and compared with those of bare base pairs. This comparison provided the changes in the spectra as a fingerprint for the structural identification of different lithiated base pairs. Also, the determination of the change in the strength of hydrogen bonds in the lithiated base pairs compared to their bare base pairs. In the other part of this study, the effect of the hydration of the attached Li+ in the structure of lithiated base pairs on the strength of their hydrogen bonds and spectra was investigated.

Insight into the binding characteristics of epigallocatechin-3-O-gallate and alcohol dehydrogenase: Based on the spectroscopic and molecular docking analysis

Alcohol dehydrogenase (ADH) is one of the pivotal enzymes for alcohol metabolism, which plays an important role in many physiological processes. In this study, the activation effects of epigallocatechin-3-O-gallate (EGCG) on ADH and the characteristics of the interaction were investigated via biochemical method, spectroscopy methods, and molecular docking. The results demonstrated that EGCG significantly increased the catalytic activity of ADH with a 33.33% activation rate and that EGCG blending slightly altered the microenvironment surrounding ADH aromatic amino acids, with an increase in the quantity of β-sheet and a decrease in the α-helix. Through the thermal stability analysis, it is further shown that the interaction of the two affects the intra-molecular hydrogen bond formation of the protein, and the conformation is partially extended. Besides, a total of 8 residues in ADH participated in the docking with EGCG, among which Asp-227, Lys-231, Glu-234, Gly-365 and Glu-366 participated in the formation of hydrogen bonds. At the same time, EGCG and amino group of Lys-231 form a noncovalent bond through cation-π interaction. In particular, hydrogen bonding was beneficial to keep the stability of EGCG-ADH, which was the primary driver of ADH activity activation. The results supply a new way for EGCG to activate ADH and a theoretical basis for the development of anti-alcoholism products.

Characterization of a unique attachment organelle: Single-cell force spectroscopy of Giardia duodenalis trophozoites

The unicellular parasite Giardia duodenalis is the causative agent of giardiasis, a gastrointestinal disease with global spread. In its trophozoite form, G. duodenalis can adhere to the human intestinal epithelium and a variety of other, artificial surfaces. Its attachment is facilitated by a unique microtubule-based attachment organelle, the so-called ventral disc. The mechanical function of the ventral disc, however, is still debated. Earlier studies postulated that a dynamic negative pressure under the ventral disc, generated by persistently beating flagella, mediates the attachment. Later studies suggested a suction model based on structural changes of the ventral discs, substrate clutching or grasping, or unspecific contact forces. In this study, we aim to contribute to the understanding of G. duodenalis attachment by investigating detachment characteristics and determining adhesion forces of single trophozoites on a smooth glass surface (RMS = 1.1 ± 0.2 nm) by fluidic force microscopy (FluidFM)-based single-cell force spectroscopy (SCFS). Briefly, viable adherent trophozoites were approached with a FluidFM micropipette, immobilized to the micropipette aperture by negative pressure, and detached from the surface by micropipette retraction while retract force curves were recorded. These force curves displayed novel and so far undescribed characteristics for a microorganism, namely, gradual force increase on the pulled trophozoite, with localization of adhesion force shortly before cell detachment length. Respective adhesion forces reached 7.7 ± 4.2 nN at 1 μm s-1 pulling speed. Importantly, this unique force pattern was different from that of other eukaryotic cells such as Candida albicans or oral keratinocytes, considered for comparison in this study. The latter both displayed a force pattern with force peaks of different values or force plateaus (for keratinocytes) indicative of breakage of molecular bonds of cell-anchored classes of adhesion molecules or membrane components. Furthermore, the attachment mode of G. duodenalis trophozoites was mechanically resilient to tensile forces, when the pulling speeds were raised up to 10 μm s-1 and adhesion forces increased to 28.7 ± 10.5 nN. Taken together, comparative SCSF revealed novel and unique retract force curve characteristics for attached G. duodenalis, suggesting a ligand-independent suction mechanism, that differ from those of other well described eukaryotes.

Rapid and Mechanically Robust Immobilization of Proteins on Silica Studied at the Single-Molecule Level by Force Spectroscopy and Verified at the Macroscopic Level

Typical methods for stable immobilization of proteins often involve time-consuming surface modification of silicon-based materials to enable specific binding, while the nonspecific adsorption method is faster but usually unstable. Herein, we fused a silica-binding protein, Si-tag, to target proteins so that the target proteins could attach directly to silica substrates in a single step, markedly streamlining the immobilization process. The adhesion force between the Si-tag and glass substrates was determined to be approximately 400-600 pN at the single-molecule level by atomic force microscopy, which is greater than the unfolding force of most proteins. The adhesion force of the Si-tag exhibits a slight increase when pulled from the C-terminus compared to that from the N-terminus. Furthermore, the Si-tag's adhesion force on a glass surface is marginally higher than that on a silicon nitride probe. The binding properties of the Si-tag are not obviously affected by environmental factors, including pH, salt concentration, and temperature. In addition, the macroscopic adhesion force between the Si-tag-coated hydrogel and glass substrates was ∼40 times higher than that of unmodified hydrogels. Therefore, the Si-tag, with its strong silica substrate binding ability, provides a useful tool as an excellent fusion tag for the rapid and mechanically robust immobilization of proteins on silica and for the surface coating of silica-binding materials.

Simultaneous photoacoustic and ultrasound imaging: A review

Photoacoustic imaging (PAI) is an emerging biomedical imaging technique that combines the advantages of optical and ultrasound imaging, enabling the generation of images with both optical resolution and acoustic penetration depth. By leveraging similar signal acquisition and processing methods, the integration of photoacoustic and ultrasound imaging has introduced a novel hybrid imaging modality suitable for clinical applications. Photoacoustic-ultrasound imaging allows for non-invasive, high-resolution, and deep-penetrating imaging, providing a wealth of image information. In recent years, with the deepening research and the expanding biomedical application scenarios of photoacoustic-ultrasound bimodal systems, the immense potential of photoacoustic-ultrasound bimodal imaging in basic research and clinical applications has been demonstrated, with some research achievements already commercialized. In this review, we introduce the principles, technical advantages, and biomedical applications of photoacoustic-ultrasound bimodal imaging techniques, specifically focusing on tomographic, microscopic, and endoscopic imaging modalities. Furthermore, we discuss the future directions of photoacoustic-ultrasound bimodal imaging technology.

Using differential mobility spectrometry to improve the specificity of targeted measurements of 2,3-dinor 11β-Prostaglandin F2α

INTRODUCTION

2,3-dinor 11β-Prostaglandin F2α (BPG) is an arachidonic acid derivative and the most abundant metabolic byproduct of prostaglandin D2, which is released during mast cell activation. Therefore, measurements of BPG in urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) provide a noninvasive method for evaluation and management of mast cell disorders. Measurements obtained by LC-MS/MS exhibit a high prevalence of chromatographic interferences resulting in challenges with optimal determination of BGP. In this investigation, differential mobility spectrometry (DMS) is utilized to overcome the limitations of current testing.

METHODS

Urine samples were extracted using an automated solid-phase extraction method. Samples were then analyzed with and without DMS devices installed on two commercially available mass spectrometry platforms to assess the benefits of DMS. Following promising results from a preliminary analytical evaluation, LC-DMS-MS/MS measurements of BPG in urine were fully validated to assess the analytical implications of using this technology.

RESULTS AND DISCUSSION

The addition of DMS devices to the LC-MS/MS systems evaluated in this investigation significantly reduced interferences observed in the chromatograms. Concomitantly, DMS reduced the number of discordant quantifier/qualifier fragment ion results that significantly exceeded the ± 20 % limits, suggesting greater analytical specificity. The validation studies yielded low interday imprecision, with %CVs less than 6.5 % across 20 replicate measurements. Validation studies assessing other aspects of analytical performance also met acceptance criteria.

CONCLUSIONS

Incorporating DMS devices greatly improved the specificity of BPG measurements by LC-MS/MS, as evidenced by the comparison of chromatograms and fragment ion results. Validation studies showed exceptional performance for established analytical metrics, indicating that this technology can be used to minimize the impact of interferences without adversely impacting other aspects of analytical or clinical performance.

Fast high-resolution prospective motion correction for single-voxel spectroscopy

PURPOSE

To develop a fast high-resolution image-based motion correction method using spiral navigators with multislice-to-volume registration.

METHODS

A semi-LASER sequence was modified to include a multislice spiral navigator for prospective motion correction (∼305 ms including acquisition, processing, and feedback) as well as shim and frequency navigators for prospective shim and frequency correction (∼100 ms for each). MR spectra were obtained in the prefrontal cortex in five healthy subjects at 3 T with and without prospective motion and shim correction. The effect of key navigator parameters (number of slices, image resolution, and excitation flip angle) on registration accuracy was assessed using simulations.

RESULTS

Without prospective motion and shim correction, spectral quality degraded significantly in the presence of voluntary motion. In contrast, with prospective motion and shim correction, spectral quality was improved (metabolite linewidth = 6.7 ± 0.6 Hz, SNR= 67 ± 9) and in good agreement with baseline data without motion (metabolite linewidth = 6.9 ± 0.9 Hz, SNR = 73 ± 9). In addition, there was no significant difference in metabolites concentrations measured without motion and with prospective motion and shim correction in the presence of motion. Simulations showed that the registration precision was comparable when using three navigator slices with 3 mm resolution and when using the entire volume (all slices) with 8 mm resolution.

CONCLUSION

The proposed motion correction scheme allows fast and precise prospective motion and shim correction for single-voxel spectroscopy at 3 T. With 3 mm resolution, only a few navigator slices are necessary to achieve excellent motion correction performance.

Cytotoxic flavonoids from the leaves of Callicarpa nudiflora hook

A new flavonoid glycoside, luteolin-3'-O-β-D-6″-acetyl glucopyranoside (1), along with six known flavonoids, were isolated from the leaves of Callicarpa nudiflora Hook. The structures of the isolated compounds were established on the basis of extensive spectroscopic analyses. Compound 6 exhibited potent cytotoxicity and compounds 1 and 7 exhibited moderate cytotoxicity against human hepatocellular carcinoma SMMC-7721 cells.

Visible light-activated curcumin-doped zinc oxide nanoparticles integrated into orthodontic adhesive on Micro-tensile bond strength, degree of conversion, and antibacterial effectiveness against Staphylococcus Aureus. An investigation using scanning electron microscopy and energy-dispersive X-ray spectroscopy

AIM

To acquire a thorough comprehension of the photoactivated Cur-doped ZnONPs at different concentrations 0%, 2.5%, and 5% on the physical qualities, antibacterial efficacy, degree of conversion, and μshear bond strength between orthodontic brackets and the enamel surface.

MATERIAL AND METHODS

An extensive investigation was carried out utilizing a range of analytical methods, scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FTIR) spectroscopy, micro tensile bond strength (μTBS) testing, and evaluation of antibacterial effectiveness. Cur-doped ZnONPs at concentrations of 2.5% and 5% were blended with Transbond XT, a light-curable orthodontic adhesive. A control group without the addition of Cur-doped ZnONPs was also prepared. The tooth samples were categorized into three groups based on the weight percentage of NPs: Group 1 (control) with 0% Cur-doped ZnONPs, Group 2 with 2.5 wt% Cur-doped ZnONPs, and Group 3 with 5 wt% Cur-doped ZnONPs. The SEM technique was employed to analyze the morphological characteristics of Cur-doped ZnONPs and ZnONPs. The composition and elemental distribution of the modified Cur-doped ZnONPs were assessed using energy-dispersive X-ray spectroscopy. The effectiveness of NPs at various concentrations against S.Mutans was gauged through the pour plate method. DC of Cur-doped ZnONPs at a region of 1608 cm-1 to 1636 cm-1 for the cured area, whereas the uncured area spanned the same range of 1608 cm-1 to 1636 cm-1 was assessed. The Adhesive Remnant Index (ARI) approach was utilized to investigate the bond failure of orthodontic brackets, while a Universal Testing Machine (UTM) was utilized to test μTBS. The Kruskal-Wallis test was employed to investigate variations in S.mutans survival rates. To determine the μTBS values, analysis of variance (ANOVA) and the post hoc Tukey multiple comparisons test were used.

RESULTS

The maximum μTBS was given and documented in group 3: 5 wt% Cur-doped ZnONPs (21.21 ± 1.53 MPa). The lowest μTBS was given in group 2: 2.5 wt% Cur-doped ZnONPs (19.58 ± 1.27 MPa). The highest efficacy against S.mutans was documented in group 3 in which 5 wt% Cur-doped ZnONPs (0.39 ± 0.15). The lowest efficacy was seen in group 1 in which no Cur-doped ZnONPs were used (6.47 ± 1.23). The ARI analysis indicated that the predominant failure was between scores 0 and 1 among all experimental groups. Control group 1 which was not modified showed the highest DC (73.11 ± 4.19).

CONCLUSION

Orthodontic adhesive, containing 5% Cur-doped ZnONPs photoactivated with visible light exhibited a favorable impact on μTBS and indicated enhanced antibacterial efficacy against S.mutans. Nevertheless, it was observed that the addition of Cur-doped ZnONPs at different concentrations (2.5%,5%) resulted in a decrease in the monomer-to-polymer ratio compromising DC.

Deciphering the binding behavior and interaction mechanism of apigenin and α-glucosidase based on multi-spectroscopic and molecular simulation studies

This study investigated the molecular mechanism underlying the binding interaction between apigenin (API) and α-glucosidase (α-glu) by a combination of experimental techniques and computational simulation strategies. The spontaneously formation of stable API-α-glu complex was mainly driven by hydrogen bonds and hydrophobic forces, leading to a static fluorescence quenching of α-glu. The binding of API induced secondary structure and conformation changes of α-glu, decreasing the surface hydrophobicity of protein. Computational simulation results demonstrated that API could bind into the active cavity of α-glu via its interaction with active residues at the binding site. The important roles of key residues responsible for the binding stability and affinity between API and α-glu were further revealed by MM/PBSA results. In addition, it can be found that the entrance of active site tended to close after API binding as a result of its interaction with gate keeping residues. Furthermore, the structural basis for the binding interaction behavior of API was revealed and visualized by weak interaction analysis. The findings of our study revealed atomic-level mechanism of the interaction between API, which might shed light on the development of better inhibitors.

Spectroscopic view on the interaction between the psoralen derivative amotosalen and DNA

Psoralens are eponymous for PUVA (psoralen plus UV-A radiation) therapy, which inter alia can be used to treat various skin diseases. Based on the same underlying mechanism of action, the synthetic psoralen amotosalen (AMO) is utilized in the pathogen reduction technology of the INTERCEPT® Blood System to inactivate pathogens in plasma and platelet components. The photophysical behavior of AMO in the absence of DNA is remarkably similar to that of the recently studied psoralen 4'-aminomethyl-4,5',8-trimethylpsoralen (AMT). By means of steady-state and time-resolved spectroscopy, intercalation and photochemistry of AMO and synthetic DNA were studied. AMO intercalates with a higher affinity into A,T-only DNA (KD = 8.9 × 10-5 M) than into G,C-only DNA (KD = 6.9 × 10-4 M). AMO covalently photobinds to A,T-only DNA with a reaction quantum yield of ΦR = 0.11. Like AMT, it does not photoreact following intercalation into G,C-only DNA. Femto- and nanosecond transient absorption spectroscopy reveals the characteristic pattern of photobinding to A,T-only DNA. For AMO and G,C-only DNA, signatures of a photoinduced electron transfer are recorded.

Monitoring the efficacy of antibiotic therapy in febrile pediatric oncology patients with bacteremia using infrared spectroscopy of white blood cells-based machine learning

Bacteremia refers to the presence of bacteria in the bloodstream, which can lead to a serious and potentially life-threatening condition. In oncology patients, individuals undergoing cancer treatment have a higher risk of developing bacteremia due to a weakened immune system resulting from the disease itself or the treatments they receive. Prompt and accurate detection of bacterial infections and monitoring the effectiveness of antibiotic therapy are essential for enhancing patient outcomes and preventing the development and dissemination of multidrug-resistant bacteria. Traditional methods of infection monitoring, such as blood cultures and clinical observations, are time-consuming, labor-intensive, and often subject to limitations. This manuscript presents an innovative application of infrared spectroscopy of leucocytes of pediatric oncology patients with bacteremia combined with machine learning to diagnose the etiology of infection as bacterial and simultaneously monitor the efficacy of the antibiotic therapy in febrile pediatric oncology patients with bacteremia infections. Through the implementation of effective monitoring, it becomes possible to promptly identify any indications of treatment failure. This, in turn, indirectly serves to limit the progression of antibiotic resistance. The logistic regression (LR) classifier was able to differentiate the samples as bacterial or control within an hour, after receiving the blood samples with a success rate of over 95 %. Additionally, initial findings indicate that employing infrared spectroscopy of white blood cells (WBCs) along with machine learning is viable for monitoring the success of antibiotic therapy. Our follow up results demonstrate an accuracy of 87.5 % in assessing the effectiveness of the antibiotic treatment.

Capacitive spectroscopy as transduction mechanism for wearable biosensors: opportunities and challenges

Wearable sensors would revolutionize healthcare and personalized medicine by providing individuals with continuous and real-time data about their bodies and environments. Their integration into everyday life has the potential to enhance well-being, improve healthcare outcomes, and offer new opportunities for research. Capacitive sensors technology has great potential to enrich wearable devices, extending their use to more accurate physiological indicators. On the basis of capacitive sensors developed so far to monitor physical parameters, and taking into account the advances in capacitive biosensors, this work discusses the benefits of this type of transduction to design wearables for the monitoring of biomolecules. Moreover, it provides insights into the challenges that must be overcome to take advantage of capacitive transduction in wearable sensors for health.

DNA polyhedrons cube, prism, and square pyramid protect the catalytic activity of catalase: A thermodynamics and kinetics study

DNA is widely used as building block material for the construction of polyhedral nanostructures. DNA polyhedrons (DNA prism, cube, and square pyramid) are small 3D wireframed nanostructures with tunable shapes and sizes. Despite substantial progress in synthesis, the study regarding cellular responses to DNA polyhedrons is limited. Herein, the molecular interaction between DNA polyhedrons and the antioxidant enzyme, catalase has been explored. The enzymatic activity of bovine liver catalase (BLC) remains unaltered in the presence of DNA polyhedrons after 1 h of incubation. However, the activity of BLC was protected after 24 h of incubation in the presence of DNA polyhedrons as compared to the natural unfolding. The kinetics study confirmed the protective role of DNA polyhedrons on BLC with lower KM and higher catalytic efficiency. Furthermore, no profound conformational changes of BLC occur in the presence of DNA polyhedrons as observed in spectroscopic studies. From fluorescence quenching data we confirmed the binding between DNA polyhedrons and BLC. The thermodynamic parameters indicate that non-covalent bonds played a major role during the interaction of BLC with DNA polyhedrons. Moreover, the hepatic catalase activity remains unaltered in the presence of DNA polyhedrons. The cytotoxicity assay revealed that DNA polyhedrons were biocompatible in the cellular environment. The protective role of DNA polyhedrons on enzyme activity and the unaltered conformational change of protein ensures the biocompatibility of DNA polyhedrons in the cellular environment.

Determination of seawater COD spectra using double-loop contraction and sorted frog optimization

This study develops a novel double-loop contraction and C value sorting selection-based shrinkage frog-leaping algorithm (double-contractive cognitive random field [DC-CRF]) to mitigate the interference of complex salts and ions in seawater on the ultraviolet-visible (UV-Vis) absorbance spectra for chemical oxygen demand (COD) quantification. The key innovations of DC-CRF are introducing variable importance evaluation via C value to guide wavelength selection and accelerate convergence; a double-loop structure integrating random frog (RF) leaping and contraction attenuation to dynamically balance convergence speed and efficiency. Utilizing seawater samples from Jiaozhou Bay, DC-CRF-partial least squares regression (PLSR) reduced the input variables by 97.5% after 1,600 iterations relative to full-spectrum PLSR, RF-PLSR, and CRF-PLSR. It achieved a test R2 of 0.943 and root mean square error of 1.603, markedly improving prediction accuracy and efficiency. This work demonstrates the efficacy of DC-CRF-PLSR in enhancing UV-Vis spectroscopy for rapid COD analysis in intricate seawater matrices, providing an efficient solution for optimizing seawater spectra.

Comprehensive spectroscopic, metabolomic, and proteomic liquid biopsy in the diagnostics of hepatocellular carcinoma

Liquid biopsy is a very topical issue in clinical diagnostics research nowadays. In this study, we explored and compared various analytical approaches to blood plasma analysis. Finally, we proposed a comprehensive procedure, which, thanks to the utilization of multiple analytical techniques, allowed the targeting of various biomolecules in blood plasma reflecting diverse biological processes underlying disease development. The potential of such an approach, combining proteomics, metabolomics, and vibrational spectroscopy along with preceding blood plasma fractionation, was demonstrated on blood plasma samples of patients suffering from hepatocellular carcinoma in cirrhotic terrain (n = 20) and control subjects with liver cirrhosis (n = 20) as well as healthy subjects (n = 20). Most of the applied methods allowed the classification of the samples with an accuracy exceeding 80.0 % and therefore have the potential to be used as a stand-alone method in clinical diagnostics. Moreover, a final panel of 48 variables obtained by a combination of the utilized analytical methods enabled the discrimination of the hepatocellular carcinoma samples from cirrhosis with 94.3 % cross-validated accuracy. Thus, this study, although limited by the cohort size, clearly demonstrated the benefit of the multimethod approach in clinical diagnosis.

Novel needle-probe single-fiber reflectance spectroscopy to quantify sub-surface myoglobin forms in beef psoas major steaks during retail display

Meat discoloration starts at the interface between the bright red oxymyoglobin layer and the interior deoxymyoglobin layer. Currently, limited tools are available to characterize myoglobin forms formed within the sub-surface of meat. The objective was to demonstrate a needle-probe based single-fiber reflectance (SfR) spectroscopy approach for characterizing sub-surface myoglobin forms of beef psoas major muscles during retail storage. A 400-μm fiber was placed in a 17-gauge needle, and the assembly was inserted into the muscle at five depths of 1 mm increment and 1 cm lateral shift. Metmyoglobin content increased at all depths during display and content at 1 mm was greater compared to that of 2 to 5 mm depth. The a* values decreased (P < 0.05) during retail display aligning with the sub-surface formation of metmyoglobin. In summary, the results suggest that needle-probe SfR spectroscopy can determine interior myoglobin forms and characterize meat discoloration.