Spectroscopic Analysis Methods Research Articles

Accumulation of zoledronic acid in rabbit intervertebral discs

Low back pain is a major chronic musculoskeletal disorder, caused mainly due the degeneration of the intervertebral discs (IVDs). Bisphosphonates (BPs), like zoledronic acid (ZOL), are used in osteoporosis management; however, their accumulation in the IVDs and their physiological role has not been addressed so far. To this end, an SPE-liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) analytical method, using on-cartridge derivatization, has been developed and validated. The analytical method presented excellent linearity (R2 > 0.992), high recoveries (67.8–82.6%), increased repeatability (0.5–9.9%) and low LOD values (21 ng g−1 in the case of IVDs) in all matrices studied. The injection of ZOL in a rabbit animal model resulted in rapid accumulation in blood plasma and the skin, followed by quick clearance. On the other hand, no ZOL was detected in nucleus pulposus, the core of the IVD, while in the peripheral annulus fibrosus a lower and delayed accumulation, as well as dispersal was found. These variations are most probably due to the avascular nature of IVD, allowing only the diffusion of small molecules in and out of the tissue, and/or to the unique physicochemical environment of IVDs. Finally, ZOL, at the concentrations found, did not affect cells’ viability or the increase of reactive oxygen species (ROS).

Brominated trihalamines in chlorinated seawaters: Quantification of tribromamine and identification of bromochloramines by Membrane Introduction Mass Spectrometry

During chlorination of seawater, the presence of bromide and ammonia alters the speciation of the oxidant and lead to the formation of chlorinated and brominated amines. This can affect the effectiveness of the disinfection treatment and the formation of disinfection by-products released to the environment. In this study, a Membrane Introduction Mass Spectrometry (MIMS) analytical method was developed to differentiate brominated trihalamines (i.e. tribromamine NBr3, dibromochloramine NBr2Cl and bromodichloramine NBrCl2) in synthetic and natural chlorinated seawater. A mass-to-charge ratio of m/z = 253 corresponding to the parent ion was used for the quantification of NBr3 in absence of organic matter and the signal of the fragment at m/z = 177 was chosen in presence of high concentration of organic matter. Limits of detection were 0.23 μM (49 μg Cl2/L) and 0.18 μM (38 μg Cl2/L) for m/z 253 and m/z 177, respectively. Both NBr2Cl and NBrCl2 were monitored in chlorinated seawaters with their respective parent ion at m/z = 207 and m/z = 163 but were not quantified. MIMS results also showed that reaction of brominated trihalamines with natural organic matter (NOM) was a minor pathway for 1–2 mg C/L compared to their auto-decomposition in natural or synthetic seawater. Overall, MIMS was able to unambiguously differentiate and monitor brominated trihalamines for the first time in chlorinated seawater, which was not possible by using UV measurement, titration and colorimetric methods.

Quantification of the irreversible fibroblast growth factor receptor inhibitor futibatinib by UPLC-MS/MS: Application to the metabolic stability assay in human liver microsomes for the estimation of its in vitro hepatic intrinsic clearance

Futibatinib (FUT) is a potent irreversible inhibitor of fibroblast growth factor receptor 1–4 currently under clinical investigation for the treatment of cholangiocarcinoma. However, there remains a paucity of information pertaining to its hepatic metabolism. In this study, our overarching aims were to systematically develop and validate a novel ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analytical method to quantify FUT for the subsequent application to the metabolic stability assay. Chromatographic separation was achieved on a C18 column and a gradient elution system comprising 0.1% formic acid in water (A) and acetonitrile (B). Positive electrospray ionization in conjunction with multiple reaction monitoring (MRM) mode was harnessed for the selective and sensitive quantification of FUT (m/z 419.2 → 296.0) and erdafitinib (m/z 447.0 → 362.0; internal standard). The retention time was 1.49 min for FUT and 1.29 min for erdafitinib. The calibration curve was linear from 0.003 to 3 µM (r2 > 0.99) and the lower limit of quantification was 0.003 µM. The intra-day and inter-day precision (% RSD) and accuracy (% bias) were all < 11.4% and < 11.3% respectively. Quality control samples were determined to be stable under several conditions routinely employed in sample preparation and UPLC-MS/MS analyses. Moreover, the liver microsomal matrix did not adversely affect the quantification of FUT. Following which, the in vitro microsomal intrinsic clearance (CLint) of FUT was calculated from our metabolic stability assay to be 29.3 µL/min/mg, thereby suggesting that it was a medium clearance drug. Finally, extrapolating the CLint with human scaling factors yielded an estimated in vitro hepatic intrinsic clearance value of 2075 mL/min. Our study reports the first UPLC-MS/MS method and offers a specific, sensitive and rapid means of determining FUT human liver microsomal stability.

Targeted proteomics and specific immunoassays reveal the presence of shared allergens between the zoonotic nematodes Anisakis simplex and Pseudoterranova decipiens

The family Anisakidae, mainly represented by Anisakis simplex s.l. and Pseudoterranova decipiens, encompasses zoonotic nematodes infecting many marine fish. Both are responsible for gastrointestinal disease in humans after ingestion of a live larva by consumption of undercooked fish, and, in the case of A. simplex, an allergic reaction may occur after consuming or even handling infected fish. Due to its phylogenetic relatedness with A. simplex, few studies investigated the allergenic potential of P. decipiens, yet none of them focused on its excretory/secretory (E/S) proteins that easily get missed when working solely on extracts from crushed nematodes. Moreover, these E/S allergens remain behind even when the larva has been removed during fish quality processing. Therefore, the aim was to investigate if Anisakis-like allergens could also be detected in both crushed and E/S P. decipiens protein extract using targeted mass spectrometry analysis and immunological methods. The results confirmed that at least five A. simplex allergens have homologous proteins in P. decipiens; a result that emphasizes the importance of also including E/S protein extracts in proteomic studies. Not only A. simplex, but also P. decipiens should therefore be considered a potential source of allergens that could lead to hypersensitivity reactions in humans.

Tunability in dimension, metal and ligand coordination modes and emission properties in Cd(II) and Zn(II) coordination networks based on 4,4’-(hydrazine-1,2-diyilidenebis(methanylylidene)) dibenzoic acid linker

Cd(II) and Zn(II) coordination polymers based on dicarboxylic azine chromophore, 4,4'-(hydrazine-1,2-diylidenebis(methanylylidene)) dibenzoic acid (H2(4-dbahz)), were obtained and include 1D coordination polymer {[Cd(4-dbahz)(dmso)2(H2O)]·(dmso)2}n (1, 2) in the forms of monoclinic and orthorhombic polymorphs, 2D coordination grid {[Zn(4-dbahz)(dmso)]·0.5(dmso·dmf)}n (3), and 3D MOF {[Cd2(4-dbahz)2(dmso)2]·dmso}n (4). The coordination compounds and H2(4-dbahz) chromophore were studied using spectroscopic (FTIR, NMR, PL) and X-ray diffraction methods of analysis. The organic chromophore H2(4-dbahz) reveals dual emission indicated by the emission bands in the high and low energy regions of spectrum. The tuning of emission properties was followed for the as-synthesized coordination polymers 1, 3, 4 and their desolvated products and showed excellent sensing of solvated dmso. The significant enhancement of photoluminescence in the blue region in 1 is associated with elimination of π-π stacking interactions due to accommodation of dmso solvent.

A review of hyperspectral image analysis techniques for plant disease detection and identif ication.

Plant diseases cause signif icant economic losses in agriculture around the world. Early detection, quantif ication and identif ication of plant diseases are crucial for targeted application of plant protection measures in crop production. Recently, intensive research has been conducted to develop innovative methods for diagnosing plant diseases based on hyperspectral technologies. The analysis of the ref lection spectrum of plant tissue makes it possible to classify healthy and diseased plants, assess the severity of the disease, differentiate the types of pathogens, and identify the symptoms of biotic stresses at early stages, including during the incubation period, when the symptoms are not visible to the human eye. This review describes the basic principles of hyperspectral measurements and different types of available hyperspectral sensors. Possible applications of hyperspectral sensors and platforms on different scales for diseases diagnosis are discussed and evaluated. Hyperspectral analysis is a new subject that combines optical spectroscopy and image analysis methods, which make it possible to simultaneously evaluate both physiological and morphological parameters. The review describes the main steps of the hyperspectral data analysis process: image acquisition and prepro cessing; data extraction and processing; modeling and analysis of data. The algorithms and methods applied at each step are mainly summarized. Further, the main areas of application of hyperspectral sensors in the diagnosis of plant diseases are considered, such as detection, differentiation and identif ication of diseases, estimation of disease severity, phenotyping of disease resistance of genotypes. A comprehensive review of scientif ic publications on the diagnosis of plant diseases highlights the benef its of hyperspectral technologies in investigating interactions between plants and pathogens at various measurement scales. Despite the encouraging progress made over the past few decades in monitoring plant diseases based on hyperspectral technologies, some technical problems that make these methods diff icult to apply in practice remain unresolved. The review is concluded with an overview of problems and prospects of using new technologies in agricultural production

Enhanced microstructure and mechanical properties of Al6061 alloy via graphene nanoplates reinforcement fabricated by stir casting

In this research, graphene/Al6061 aluminum matrix nanocomposites were fabricated by stir casting, and the influence of graphene nanoplates on microstructure and mechanical properties of the 6061 aluminum alloy were investigated by field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy, tensile and hardness testing analysis methods. The major limitation in the utilization of 6061 aluminum alloy in heavy stress applications such as airplane fuselages, wings, internal panels, and luxury vehicles chassis is low strength and hardness. This deficiency of 6061 aluminum alloy was tackled by successful reinforcement of graphene nanoplates in 2, 4, 6, 8 and 10 wt.%, using the stir casting process. The FESEM micrographs showed that the graphene nanoplates were uniformly distributed in the 6061-aluminum matrix alloy and tensile strength, hardness, and yield strength enhanced remarkably as compared with unreinforced 6061 aluminum alloy. The as-cast tensile strength, hardness, and yield strength of the graphene/Al6061 nanocomposites were improved by 127%, 158%, and 402%, respectively, compared with the unreinforced Al6061 alloy. It is concluded that the nano thickness of graphene, reinforcement quantity, and manufacturing process are the major factors for the enhancement of microstructure and mechanical properties of graphene/Al6061 nanocomposites.

Emerging Electrochemical Techniques for Probing Site Behavior in Single-Atom Electrocatalysts.

Single-atom catalysts (SACs) have aroused tremendous interest over the past decade, particularly in the community of energy and environment-related electrocatalysis. A rapidly growing number of recent publications have recognized it as a promising candidate with maximum atomic utilization, distinct activity, and selectivity in comparison to bulk catalysts and nanocatalysts. However, the complexity of localized coordination environments and the dispersion of isolated sites lead to significant difficulties when it comes to gaining insight into the intrinsic behavior of electrocatalytic reactions. Furthermore, the low metal loadings of most SACs make conventional ensemble measurements less likely to be accurate on the subnanoscale. Thus, it remains challenging to probe the activity and properties of individual atomic sites by available commercial instruments and analytical methods. In spite of this, continuing efforts have lately focused on the development of advanced measurement methodologies, which are very useful to the fundamental understanding of SACs. There have recently been a number of in situ/operando techniques applied to SACs, such as electron microscopy, spectroscopy, and other analysis methods, which support relevant functions to identify the active sites and reaction intermediates and to investigate the dynamic behavior of localized structures of the catalytic sites.This Account aims to present recent electrochemical probing techniques which can be used to identify single-atomic catalytic sites within solid supports. First, we describe the basic principles of molecular probe methods for the study and analysis of electrocatalytic site behavior. In particular, the in situ probing technique enabled by surface interrogation scanning electrochemical microscopy (SI-SECM) can measure the active site density and kinetic rate with high resolution. An alternative electrochemical probing technique is further demonstrated on the basis of single-entity electrochemistry, which allows the unique electrochemical imaging of the size and catalytic rate of single atoms, molecules, and clusters. The merits and limitations of different electrochemical techniques are then discussed, along with perspectives for future prospects. Apart from this, we further showcase the powerful capability of emerging electrochemical probing techniques for determining significant effects and properties of SACs for various electrocatalytic reactions, including oxygen reduction and evolution, hydrogen evolution, and nitrate reduction. Overall, electrochemical techniques with atomic resolution have greatly increased opportunities for observing, measuring, and understanding the surface and interface chemistry during energy conversion. In the future, it is anticipated that the development of electrochemical probing techniques will be advanced with innovative perspectives on the behavior and features of SACs. We hope that this Account can contribute in several ways to promoting the fundamental knowledge and technical progress of emerging electrochemical measurements for studying SACs.

Simultaneous Analysis for Quality Control of Traditional Herbal Medicine, Gungha-Tang, Using Liquid Chromatography-Tandem Mass Spectrometry.

Gungha-tang (GHT), a traditional herbal medicine, consists of nine medicinal herbs (Cnidii Rhizoma, Pinelliae Tuber, Poria Sclerotium, Citri Unshius Pericarpium, Citri Unshius Pericarpium Immaturus, Aurantii Fructus Immaturus, Atracylodis Rhizoma Alba, Glycyrrhizae Radix et Rhizoma, and Zingiberis Rhizoma Recens). It has been used for various diseases caused by phlegm. This study aimed to develop and verify the simultaneous liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis method, using nine marker components (liquiritin apioside, neoeriocitrin, narirutin, naringin, hesperidin, neohesperidin, liquiritigenin, glycyrrhizin, and 6-shogaol) for quality control of GHT. LC–MS/MS analysis was conducted using a Waters TQ-XS system. All marker analytes were separated on a Waters Acquity UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm) using gradient elution with a distilled water solution (containing 5 mM ammonium formate and 0.1% [v/v] formic acid)–acetonitrile mobile phase. LC–MS/MS multiple reaction monitoring (MRM) analysis was carried out in negative and positive ion modes of an electrospray ionization source. The developed LC–MS/MS MRM method was validated by examining the linearity, limits of detection and quantification, recovery, and precision. LOD and LOQ values of nine markers were calculated as 0.02–8.33 ng/mL and 0.05–25.00 ng/mL. The recovery was determined to be 89.00–118.08% and precision was assessed with a coefficient of variation value of 1.74–8.64%. In the established LC–MS/MS MRM method, all markers in GHT samples were detected at 0.003–16.157 mg/g. Information gathered during the development and verification of the LC–MS/MS method will be useful for the quality assessment of GHT and other herbal medicines.

UPLC-PDA-MS/MS Profiling and Healing Activity of Polyphenol-Rich Fraction of Alhagi maurorum against Oral Ulcer in Rats.

Camelthorn, Alhagi maurorum Boiss, family Fabaceae has long been used in African folk medicine owing to its richness in pharmacologically active metabolites. The crude extract (CEAM), ethyl acetate fraction (EFAM) and n-butanol (BFAM) fraction of A. maurorum aerial parts were investigated for their total polyphenols and oral antiulcer activity using in-vitro and in-vivo models. The major phenolic compound was isolated from the polyphenol-rich EFAM fraction and identified by conventional and spectroscopic methods of analysis as isorhamnetin-3-O-rutinoside. Furthermore, standardization of EAFM using UPLC-PDA-UV quantified isorhamnetin-3-O-rutinoside as 262.91 0.57 g/mg of the fraction. Analysis of EFAM using UPLC-PDA-MS/MS revealed tentative identification of 25 polyphenolic compounds. EFAM exhibited the most potent free radical scavenging activity against DPPH, with an IC50 (27.73 ± 1.85 µg/mL) and an FRAP value of (176.60 ± 5.21 μM Trolox equivalent (TE)/mg fraction) in comparison with CEAM and BFAM. Acetic acid-induced oral ulcers in a rat model were used to evaluate the healing properties of A. maurorum aerial parts. EFAM significantly decreased tumor necrosis factor-alpha (TNF-α) and interleukin-2 (IL-2) by 36.4% and 50.8%, respectively, in the ulcer tissues while, CEAM and BFAM exhibited lower activity at the same dose. In addition, EFAM led to a significant (p < 0.0001) rise in the expression of proliferating cell nuclear antigen (PCNA), a cell proliferation marker. A. maurorum exhibited a potent healing effect in acetic acid-induced oral ulcers in rats by mitigating the release of pro-inflammatory cytokines and improving PCNA expression.

Development of three ecological spectroscopic methods for analysis of betrixaban either alone or in mixture with lercanidipine: greenness assessment.

Three eco-friendly spectrophotometric methods were developed for determination of the novel anticoagulant drug, betrixaban (BTX). The first method (method A) was based on direct analysis of BTX at 229.4 nm on the zero-order spectrum using methanol as the optimum solvent. While the second method (method B) was based on measuring difference absorption value (ΔA) of BTX at 335 nm, which was obtained from pH-induced spectral difference (difference spectra of BTX in 0.1 M NaOH versus 0.1 M HCl). The third method (method C) was based on measurement of the first-derivative amplitudes of BTX and its co-administered Ca channel blocker lercanidipine (LER) at 304 and 229 nm for simultaneous assay of BTX and LER, respectively. All methods were linear over concentration ranges of 1.0–20.0 and 8.0–80.0 µg ml−1 for BTX in methods A and B, respectively, and of 1.0–20.0 and 1.0–25.0 µg ml−1 for BTX and LER, respectively, in method C. The three methods were fully validated and assessed for greenness by three metrics: analytical eco-scale, green analytical procedure index and Analytical GREEnness metrics. The results indicated the validity and greenness of the proposed methods. Moreover, the methods were applied to assay the studied analytes in their dosage forms with high percentage of recovery and low percentage of relative s.d. values.

Development and application of high resolution mass spectrometry analytical method to study and identify the photoinduced transformation products of environmental pollutants

Terpenes are among the major causes of pleasant or unpleasant odors close to active or inactive landfills. We studied R-limonene and p-cymene environmental degradation products using the heterogeneous photocatalysis mediated by titanium dioxide to explore the odor pollution. The aim of the study was the development of mass spectrometry based methods both hyphenated with GC and HPLC to identify and characterize transformation products (TPs) derived from photodegradation of R-limonene and p-cymene. With the GC-MS method we identified three TPs for R-limonene and two for p-cymene comparing the obtained mass spectra with those in the NIST library. While with HPLC-MS method, thanks to the use of the high resolution of MS tool, we recognized four and five TPs for R-limonene and p-cymene respectively. No p-cymene was detected as R-limonene transformation product. The methods developed were then applied to real environmental samples coming from landfills active (Lan1) or inactive (Lan2 and Lan3) located in northern Italy. R-limonene was detected in the active landfill (Lan1 at the concentration of 2.35 μg/mL) together with one of its TPs and one TP derived from p-cymene. p-Cymene was detected in the other two inactive landfills (Lan2 and Lan3 concentrations 0.025 and 0.15 μg/mL, respectively) together with one of its TP and two TPs coming from R-limonene photodegradation. The finding of TPs together with R-limonene and p-cymene both in active and inactive landfills point out the attention on the reduction of these molecules in the environment to reduce pollution and human risks.

Dynamical parallax, physical parameters, and evolutionary status of the components of the bright eclipsing binary α Draconis

Aims. Both components of the bright eclipsing binary α Dra have been resolved using long baseline interferometry and the secondary component has been shown to contribute approximately 15% of the total flux; however, a spectroscopic detection of the companion star has so far been unsuccessful. We aim for a firm spectroscopic detection of the secondary component of α Dra using state-of-the-art spectroscopic analysis methods for very high-quality spectroscopic observations. This will allow the determination of fundamental and atmospheric properties of the components in the system with high precision and accuracy. Methods. To achieve our goals, we use a combined data set from interferometry with the Navy Precision Optical Interferometer (NPOI), photometry with the TESS space observatory, and high-resolution spectroscopy with the HERMES fibre-fed spectrograph at the La Palma observatory. We use the method of spectral disentangling to search for the contribution of a companion star in the observed composite HERMES spectra, to separate the spectral contributions of both components, and to determine orbital elements of the α Dra system. TESS light curves are analysed in an iterative fashion with spectroscopic inference of stellar atmospheric parameters to determine fundamental stellar properties and their uncertainties. Finally, NPOI interferometric measurements are used for determination of the orbital parameters of the system and angular diameters of both binary components. Results. We report the first firm spectroscopic detection of the secondary component in α Dra and deliver disentangled spectra of both binary components. The components’ masses and radii are inferred with high precision and accuracy, and are MA = 3.186 ± 0.044 M⊙, RA = 4.932 ± 0.036 R⊙, and MB = 2.431 ± 0.019 M⊙, RB = 2.326 ± 0.052 R⊙ for the primary and secondary components, respectively. Combined astrometric and spectroscopic analysis yields the semi-major axis of the system, which is ultimately used to derive the dynamical parallax of π = 11.48 ± 0.13 mas, and the distance d = 87.07 ± 1.03 pc to the α Dra system. Evolutionary analysis of both binary components with MESA stellar structure and evolution models suggests the primary is an evolved post-TAMS A-type star, while the companion is a main-sequence A-type star with a convective core mass of Mcc = 0.337 ± 0.011 M⊙. Positions of both binary components in the Kiel- and HR-diagrams suggest a value of the convective core overshooting parameter fov well below 0.010 Hp, and we infer the age of the system to be 310 ± 25 Myr. Conclusions. The inferred near-core mixing properties of both components do not support a dependence of the convective core overshooting on the stellar mass. At the same time, the α Dra system provides extra support to hypothesise that the mass discrepancy in eclipsing spectroscopic double-lined binaries is associated with inferior atmospheric modelling of intermediate- and high-mass stars, and less so with the predictive powerof stellar structure and evolution models as to the amount of near-core mixing and mass of the convective core.

Manganese-Mediated C–H Bond Activation of Fluorinated Aromatics and the ortho-Fluorine Effect: Kinetic Analysis by In Situ Infrared Spectroscopic Analysis and Time-Resolved Methods

Manganese-Mediated C–H Bond Activation of Fluorinated Aromatics and the <i>ortho</i>-Fluorine Effect: Kinetic Analysis by <i>In Situ</i> Infrared Spectroscopic Analysis and Time-Resolved Methods

6PPD-Quinone: Revised Toxicity Assessment and Quantification with a Commercial Standard

Stormwater exposure can cause acute mortality of coho salmon (Oncorhynchus kisutch), and 6PPD-quinone (6PPD-Q) was identified as the primary causal toxicant. Commercial standards of 6PPD-Q recently became available; their analysis highlighted a systematic high bias in prior reporting concerning 6PPD-Q. A 6PPD-Q commercial standard was used to re-confirm toxicity estimates in juvenile coho salmon and develop a liquid chromatography-tandem mass spectrometry analytical method for quantification. Peak area responses of the commercial standard were ∼15 times higher than those of in-house standards, and the updated LC50 value (95 ng/L) was ∼8.3-fold lower than that previously reported. These data support prior relative comparisons of the occurrence and toxicity while confirming the substantial lethality of 6PPD-Q. While environmental concentrations are expected to be lower, 6PPD-Q also was more toxic than previously calculated and should be categorized as a “very highly toxic” pollutant for aquatic organisms. Isotope dilution-tandem mass spectrometry methods enabled accurate quantification (limits of quantification of <10 ng/L) within environmental samples.

Phytochemical Analysis and Bioactivity Screening of Primary and Secondary Metabolic Products of Medicinal Plants in the Valleys of Medina Region Saudi Arabia

Medicinal plants are highly valued for their active compounds. These plants can be used in various fields and preservation of these plants in their environment. The present study aimed to screen medicinal plants used in traditional medicine in Medina valleys for the presence of metabolites, and to answer the following question: is the ethnomedicinal importance of medicinal plants used in Medina valleys conform to their primary and secondary metabolite content. Eight plants (Pulicaria incise, Heliotropium arbainense, Commicarpus grandiflorus, Rumex vesicarius, Senna alexandrina, Rhazya stricta, Withania somnifera and Asphodelus fistulosus) were collected from the Medina valleys and were biochemically analyzed to determine the different compounds after leaves extraction analyzed statistically to clarify the content of primary compounds. The chemical compounds in the most active fraction were determined using quantitative phytochemical and gas chromatography-mass spectrometry (GC/MS) analytical methods, comparing the mass spectra of the GC/MS identified compounds with those of the Center of Excellence in Environmental Studies (CEES) database library. The result showed 16 aroma compounds representing the GC/MS analysis revealed the presence of various compounds like 4,4-Dimethyl octane, 5H-1-Pyrindine and 1,3- Cyclopentadiene, 1,2,5,5-tetramethyl- in the ethanolic extract of Pulicaria incisa. The most prevalent plants were Pulicaria incisa, Senna alexandrina and Heliotropium arbainense the study plants have high content of protein. There is a need to focus phytochemical screening on ethnobotanical studies to complete research into traditional medicine which leads to the discovery of new drugs.

A New Method for Finding the Limits of Quantification of Elements, Estimating Dynamic Range, and Detecting Matrix and Interelement Interferences in Spectral Analysis (Atomic Absorption Spectrometry and ICP Analysis Methods)

A New Method for Finding the Limits of Quantification of Elements, Estimating Dynamic Range, and Detecting Matrix and Interelement Interferences in Spectral Analysis (Atomic Absorption Spectrometry and ICP Analysis Methods)

Development of a Simultaneous Liquid Chromatography-Tandem Mass Spectrometry Analytical Method for Urinary Endogenous Substrates and Metabolites for Predicting Cytochrome P450 3a4 Activity

Development of a Simultaneous Liquid Chromatography-Tandem Mass Spectrometry Analytical Method for Urinary Endogenous Substrates and Metabolites for Predicting Cytochrome P450 3a4 Activity

Aging mechanisms analysis of Graphite/LiNi0.80Co0.15Al0.05O2 lithium-ion batteries among the whole life cycle at different temperatures

Lithium-ion batteries (LIBs) are widely used in electric vehicles, while capacity fading happens due to unwanted side reactions during cycling. Therefore, it is of great significance to study the aging mechanisms of LIBs among the whole life cycle for the use and design of LIBs. In this study, the aging experiments of Graphite/LiNi0.80Co0.15Al0.05O2 (NCA) batteries were conducted at 25°C and 45°C, the aging mechanisms were examined by differential voltage analysis method and electrochemical impedance spectroscopy analysis method, and verified by microscopic morphology observation. The results show that the loss of anode active material and lithium ions are the main degradation modes, and the lithium plating side reaction at the late aging stage is the inducement of capacity plunge both at 25°C and 45°C. But the causes of lithium plating are different, at 25 °C, the growth of solid electrolyte interphase (SEI) leads to lithium plating, while at 45 °C, the accumulation of gas leads to lithium plating.

Single-Cell Digital Microfluidic Mass Spectrometry Platform for Efficient and Multiplex Genotyping of Circulating Tumor Cells.

Gene mutation profiling of heterogeneous circulating tumor cells (CTCs) offers comprehensive and real-time molecular information of tumors for targeted therapy guidance, but the lack of efficient and multiplex genotyping techniques for single-CTC analysis greatly hinders its development and clinical application. This paper reports a single-CTC mass spectrometry analysis method for efficient and multiplex mutation profiling based on digital microfluidics. Digital microfluidics affords integrated single-CTC manipulation, from single-CTC isolation to high-performance whole genome amplification, via nanoliter droplet-based wettability trapping and hydrodynamic adjustment of cell distribution. Coupled with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, multiplex mutation information of individual CTCs can be efficiently and accurately identified by the inherent mass differences of different DNA sequences. This platform achieves Kirsten rat sarcoma viral oncogene mutation profiling of heterogeneous CTCs at the single-cell level from cancer patient samples, offering new avenues for genotype profiling of single CTCs and cancer therapy guidance.