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[Display omitted] • The orientation-dependent growth mechanism of Cr-rich oxide precipitate is revealed. • The directed growth is thermodynamically preferred than the isotropic growth. • The outward diffusion of Fe atom leaving vacancies which enhancing the Cr diffusion. • O promotes the aggregation of Cr atoms along the [1 0 0] direction. Advanced characterization techniques and atomic simulations, including density functional theory calculation and molecular dynamics simulation, are performed to reveal the orientation-dependent growth mechanism of Cr-rich oxide precipitates in the internal oxide layer of Fe-9Cr steel under supercritical water environment. A new Fe/Cr/O/H reactive force field is constructed to address the limitations of existing empirical potentials in accurately describing the corrosion mechanism of FeCr alloy. The high-resolution characterization reveals the growth mechanism of needle-like FeCr 2 O 4 precipitates in the <1 0 0> direction of the matrix. Atomic simulation demonstrate that the directed growth is thermodynamically preferred than the isotropic growth. The vacancies generated by the outward diffusion of metal atoms enhancing the diffusion of Cr atoms, and O promote the aggregation of Cr atoms along the <1 0 0> direction. [ABSTRACT FROM AUTHOR]

Normalized difference vegetation index (NDVI), derived from the near-infrared and red bands of a multispectral (MS) image, has been widely used in remote sensing. To obtain a high-resolution (HR) NDVI, existing attempts typically first generate an HR-MS image using pansharpening and then calculate the HR NDVI accordingly. However, some inaccurate spatial information will be simultaneously introduced into NDVIs, influencing their spatial quality seriously. To overcome this challenge, we investigate a computational fusion approach from a novel perspective for HR NDVI in this study. Rather than pansharpening an HR-MS image, we define an HR vegetation index calculated based on an available HR panchromatic image and an estimated HR red band (VIPR) and fuse the low-resolution (LR) NDVI and HR VIPR directly to acquire an HR NDVI. In particular, we adopt a nonlocal gradient sparsity constraint to force a similar nonlocal spatial structure in the fused NDVI and VIPR, where the VIPR is dynamically updated by adding a constraint to reconstruct the HR red band. We further integrate a data fidelity term to constrain the relationship between the fused NDVI and its LR version, and an efficient strategy based on the alternative direction multiplier method is developed to solve the nonconvex optimization problem. The extensive experimental results demonstrate that the proposed method achieves superior fusion performance over the state of the art, exhibiting its wide application aspect in remote sensing. [ABSTRACT FROM AUTHOR]

Due to its great performance, tungsten (W) and W-based alloys have been considered as the candidates for plasma-faced materials in future fusion reactors. However, the radiation-induced segregation under the reactor environment is one of the key issues to limit the long-term service properties of W-based alloys, and the understanding of nucleation and growth mechanisms of Re-rich precipitates is still incomplete. In the present study, both molecular dynamics (MD) and variance-constrained semi-grand canonical ensemble Monte Carlo (VC-SGC-MC) methods are employed to investigate the nucleation and growth mechanisms of Re clusters precipitated in W-Re alloys under cumulative flux irradiation. It is found that all segregated Re-rich clusters in the model alloys without irradiation are a plate-like structure (χ-phase) which orientates along the <110>, while they change to a needle-like structure (σ-phase) orienting along the <111> direction after irradiation. The combination of defects and Re atoms in W-Re alloys are considered with the most probable nucleation precursors. The Re-rich clusters will pin the interstitials and form stable nucleation sites. During the process of cumulative flux irradiation, newborn defects will be trapped by the nucleation site promoting the growth of Re clusters. [ABSTRACT FROM AUTHOR]

A computational tool was developed to facilitate proanthocyanidin analysis using data collected by ultra-high-performance liquid chromatography-diode array detection-high resolution accurate mass-mass spectrometry (UHPLC-DAD-HRAM-MS). Both identification and semi-quantitation of proanthocyanidins can be achieved by the developed computational tool. It can extract proanthocyanidin chromatographic peaks, deconvolute the isotopic patterns of A-type, B-type, and multi-charged proanthocyanidins ions, and predict proanthocyanidin structures. Proanthocyanidins were quantified by an external calibration curve of catechin and molar relative response factors (MRRFs) of proanthocyanidins. Quantitation results including concentrations of total proanthocyanidins, individual proanthocyanidins, and proanthocyanidins with different degrees of polymerization and different types of linkage were calculated by the program and exported into an Excel spreadsheet automatically. The program was applied to the analysis of seven plant materials including apple, cranberry, dark chocolate, grape seed extract, jujube, litchi, and mangosteen. The identification results were compared with the results obtained by manual processing. The program can greatly save the time needed for the data analysis of proanthocyanidins. [ABSTRACT FROM AUTHOR]

Two simple fingerprinting methods, flow-injection coupled to ultraviolet spectroscopy and proton nuclear magnetic resonance, were used for discriminating betweenAurantii fructus immaturusandFructus poniciri trifoliatae immaturus. Both methods were combined with partial least-squares discriminant analysis. In the flow-injection method, four data representations were evaluated: total ultraviolet absorbance chromatograms, averaged ultraviolet spectra, absorbance at 193, 205, 225, and 283 nm, and absorbance at 225 and 283 nm. Prediction rates of 100% were achieved for all data representations by partial least-squares discriminant analysis using leave-one-sample-out cross-validation. The prediction rate for the proton nuclear magnetic resonance data by partial least-squares discriminant analysis with leave-one-sample-out cross-validation was also 100%. A new validation set of data was collected by flow-injection with ultraviolet spectroscopic detection two weeks later and predicted by partial least-squares discriminant analysis models constructed by the initial data representations with no parameter changes. The classification rates were 95% with the total ultraviolet absorbance chromatograms datasets and 100% with the other three datasets. Flow-injection with ultraviolet detection and proton nuclear magnetic resonance are simple, high throughput, and low-cost methods for discrimination studies. [ABSTRACT FROM AUTHOR]

A fuzzy chromatography mass spectrometric (FCMS) fingerprinting method combined with chemometric analysis has been established for rapid discrimination of whole-grain flour (WF) from refined wheat flour (RF). Bran, germ, endosperm, and WF from three local cultivars or purchased from a grocery store were studied. The state of refinement (whole vs. refined) of wheat flour was differentiated successfully by use of principal-components analysis (PCA) and soft independent modeling of class analogy (SIMCA), despite potential confounding introduced by wheat class (red vs. white; hard vs. soft) or resources (different brands). Twelve discriminatory variables were putatively identified. Among these, dihexoside, trihexoside, apigenin glycosides, and citric acid had the highest peak intensity for germ. Variable line plots indicated phospholipids were more abundant in endosperm. Samples of RF and WF from three cultivars (Hard Red, Hard White, and Soft White) were physically mixed to furnish 20, 40, 60, and 80 % WF of each cultivar. SIMCA was able to discriminate between 100 %, 80 %, 60 %, 40 %, and 20 % WF and 100 % RF. Partial least-squares (PLS) regression was used for prediction of RF-to-WF ratios in the mixed samples. When PLS models were used the relative prediction errors for RF-to-WF ratios were less than 6 %. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

RATIONALE: Using one or two 2H-atom-labeled analogs as internal standards (ISs) may cause a 'cross-contribution' problem (i.e., the overlap of ions from the IS and the analyte) especially for halogenated volatile organic compounds (VOCs). However, in this situation the overlapping peak clusters of the analyte and ISs can be resolved by multivariate chemometric methods such as classical least-squares (CLS) and inverse least-squares (ILS). METHODS: Trichloroethylene (TCE) and its internal standard, deuterated TCE (TCE-d), as model compounds, were analyzed using portable gas chromatography/mass spectrometry. CLS and ILS were applied to resolve overlapping TCE and TCE-d mass spectral signals and evaluated for the determination of TCE. CLS and ILS models were constructed and used to predict concentration ratios of TCE to TCE-d. Calibration samples were prepared by adding TCE at different concentrations and TCE-d at 300 ng mL-1 as an IS. RESULTS: The calibration curve was linear over a range of 10-1000 ng mL-1 with a coefficient of determination (R2) of 0.993. A validation data set collected 2 weeks later was used to further test the model robustness. Lower prediction errors and higher correlation coefficients were obtained from TCE/TCE-d ratios predicted by the CLS model. CONCLUSIONS: This paper describes the first application of CLS to deconvolute overlapping peaks between an analyte and its corresponding isotopic internal standard for quantification. The proposed method enables simple isotopic analogs of analytes (one H or C atom is isotopically labeled) to be used as internal standards for analytes with isotopic distributions. It has wide application because of the environmental impact and prevalence of halogenated VOCs, especially when analytes have isotopic distributions that overlap with an internal standard or when sophisticated isotopic analogs of the analytes with three or more 2H- or/and 13C-atoms are prohibitively expensive or even impossible. [ABSTRACT FROM AUTHOR]

Multivariate partial least-squares (PLS) method was applied to the quantification of two complex polychlorinated biphenyls (PCBs) commercial mixtures, Aroclor 1254 and 1260, in a soil matrix. PCBs in soil samples were extracted by headspace solid phase microextraction (SPME) and determined by gas chromatography/mass spectrometry (GC/MS). Decachlorinated biphenyl (deca-CB) was used as internal standard. After the baseline correction was applied, four data representations including extracted ion chromatograms (EIC) for Aroclor 1254, EIC for Aroclor 1260, EIC for both Aroclors and two-way data sets were constructed for PLS-1 and PLS-2 calibrations and evaluated with respect to quantitative prediction accuracy. The PLS model was optimized with respect to the number of latent variables using cross validation of the calibration data set. The validation of the method was performed with certified soil samples and real field soil samples and the predicted concentrations for both Aroclors using EIC data sets agreed with the certified values. The linear range of the method was from 10 μg kg −1 to 1000 μg kg −1 for both Aroclor 1254 and 1260 in soil matrices and the detection limit was 4 μg kg −1 for Aroclor 1254 and 6 μg kg −1 for Aroclor 1260. This holistic approach for the determination of mixtures of complex samples has broad application to environmental forensics and modeling. [ABSTRACT FROM AUTHOR]

A novel fast screening method was developed for the determination of polychlorinated biphenyls that are constituents of the commercial mixture, Aroclor 1260, in soil matrices by gas chromatography with mass spectrometry combined with solid-phase microextraction. Nonequilibrium headspace solid-phase microextraction with a 100 μm polydimethylsiloxane fiber was used to extract polychlorinated biphenyls from 0.5 g of soil matrix. The use of 2 mL of saturated potassium dichromate in 6 M sulfuric acid solution improved the reproducibility of the extractions and the mass transfer of the polychlorinated biphenyls from the soil matrix to the microextraction fiber via the headspace. The extraction time was 30 min at 100°C. The percent recoveries, which were evaluated using an Aroclor 1260 standard and liquid injection, were within the range of 54.9-65.7%. Two-way extracted ion chromatogram data were used to construct calibration curves. The relative error was <±15% and the relative standard deviation was <15%, which are respective measures of the accuracy and precision. The method was validated with certified soil samples and the predicted concentrations for Aroclor 1260 agreed with the certified values. The method was demonstrated to be linear from 10 to 1000 ng/g for Aroclor 1260 in dry soil. [ABSTRACT FROM AUTHOR]

Seven polychlorinated biphenyls (PCBs) commercial mixtures, Aroclor 1016, 1221, 1232, 1242, 1248, 1254, and 1260, were analyzed by gas chromatography/mass spectrometry (GC/MS) combined with solid phase microextraction (SPME). Three pattern recognition methods: a fuzzy rule-building expert system (FuRES), partial least-squares discriminant analysis (PLS-DA), and a fuzzy optimal associative memory (FOAM) were used to build classification models. Modulo compression was introduced for data preprocessing to extract the characteristic features and compress the data size. Baseline correction and data normalization were also applied prior to data processing. Four GC/MS data set configurations were constructed and used to evaluate the classifiers and data pretreatments including two-way modulo compressed, two-way data, one-way total ion current and one-way total mass spectrum. The results indicate that modulo compression and baseline correction methods significantly improved the performance of the classifiers which resulted in improved classification rates for FuRES, PLS-DA, and FOAM classifiers. By using two-way modulo compressed data sets, the average classification rates with FuRES, PLS-DA, and FOAM were 100±0%, 94.6±0.7%, and 96.1±0.6% for 100 bootstrapped Latin partitions of the Aroclor standards. The classifiers were validated by application to Aroclor samples extracted from soil with no parametric changes except that the calibration set of standards and validation set of soil samples were individually mean centered. The classification rates for the GC/MS modulo 35 compressed data obtained from the Aroclor soil samples with FOAM, FuRES, and PLS-DA were 100%, 96.4%, and 78.6%, respectively. Therefore, a chemometric pipeline for SPME-GC/MS data coupled with chemometric analysis was devised as a fast authentication method for different Aroclors in soil. [ABSTRACT FROM AUTHOR]

A rapid and sensitive LC–MS–MS method for the quantitation of sertraline in human plasma was developed and validated. Sertraline and the internal standard, telmisartan, were cleaned up by protein precipitation from 100 μL of plasma sample, and analyzed on a TC–C18 column (5 μm, 150 × 4.6 mm i.d.) using 70% acetonitrile and 30% 10 mM ammonium acetate (0.1% formic acid) as mobile phase. The method was demonstrated to be linear from 0.1 ng/mL to 50 ng/mL with the lower limit of quantitation of 0.1 ng/mL. Intra- and inter-day precision were below 4.40% and 3.55%. Recoveries of sertraline at low, medium, and high levels were 88.0 ± 2.3%, 88.2 ± 1.9%, and 90.0 ± 2.0%, respectively. The method was successfully applied to a bioequivalence study of sertraline after a single oral administration of 50 mg sertraline hydrochloride tablets. [ABSTRACT FROM AUTHOR]

Abstract: A rapid and sensitive method for the simultaneous quantitation of hydrochlorothiazide (HCT) and metoprolol (MET) in human plasma based on liquid chromatography–tandem mass spectrometry (LC–MS/MS) has been developed and validated. MS/MS detection involved switching the electrospray ionization (ESI) mode during chromatography from negative to detect HCT and its internal standard (I.S.) 5-bromouracil to positive to detect MET and its I.S. tramadol. Sample preparation by liquid–liquid extraction with diethyl ether–dichloromethane (60:40, v/v) was followed by chromatography on a Venusil MP-C18 column using methanol–ammonium acetate (10mM)–formic acid (pH 3.4) (50:50:0.05, v/v/v) at a flow rate of 0.8mL/min. The method was linear in the concentration range 3–1000ng/mL for both HCT and MET using 100μL human plasma. Intra- and inter-day precisions (as relative standard deviation) for HCT were 2.9–3.9% and 3.9–4.7%, respectively and for MET were 2.4–4.1% and 4.7–6.2%, respectively. Accuracies (as relative error) were ±3.8% and ±2.6% for HCT and MET, respectively. The assay was successfully applied to a pharmacokinetic study involving a single oral dose of a combination tablet (25mg HCT, 50mg MET) in healthy volunteers. [Copyright &y& Elsevier]

Abstract: Voltage-dependent persistent inward currents (PICs) which underlie the plateau potentials are an important intrinsic property of spinal motoneurons. Electrophysiological experiments have indicated that a subtype of the low threshold L-type calcium channel, CaV1.3, mediates this current. In mouse and turtle lumbar spinal cord it has been shown that these channel proteins are mainly found on motoneuron dendrites. In the present study we have used immunohistochemistry to locate these channels in lumbar spinal neurons, especially motoneurons, of the cat. The results indicate that CaV1.3 immunoreactivity was unevenly distributed among the laminae of the spinal grey matter. The small neurons in superficial dorsal horn (laminae I–III) were sparsely and weakly labelled, while large neurons in ventral horn were frequently and densely labelled. Groups of motoneurons in lamina IX that were immunoreactive to choline acetyltransferase also co-expressed CaV1.3. The immmunoreactivity was mainly associated with neuronal somata and proximal dendrites. Double staining with antibodies against CaV1.3 and MAP2 (a dendritic marker) showed that some fine fibres, which may include distal dendrites, were also labelled. These results in the cat spinal cord show some differences from studies in mouse and turtle motoneurons where the immunoreactivity against this channel was mainly localized to the dendrites. [Copyright &y& Elsevier]

We used cross-correlation analysis to characterize the incidence and strength of stimulus-induced neuronal synchronization in different layers of SI barrel cortex and as a function of neuronal location in different barrel columns. To reduce the possibility of evoking responses that were coordinated by simultaneous whisker movements, multiple whiskers were sequentially stimulated with airjets that moved back-and-forth across the peripheral whisker pad. From a sample of 627 neurons, we characterized 1,182 neuron pairs and found that 687 (58.1%) of these displayed significant peaks of synchronized activity that exceeded the 99.9% confidence limits. Whereas 88% of the infragranular neuron pairs were synchronized during whisker stimulation, only 30% of the neuron pairs in the granular or supragranular layers displayed synchronized responses. The strength of synchronization, as measured by the correlation coefficient, was significantly higher in the infragranular layers than in the other layers. These results indicate that synchronized outputs from the infragranular layers do not depend on synchronized inputs from the upper cortical layers. We also found that synchronization varies with the spatial configuration of the neurons and is strongest for neuron pairs residing in the same row. Given the dense local projections between neighboring barrel columns in the same row, our results indicate that neuronal synchronization is greatest when stimuli simultaneously activate those peripheral receptors whose cortical representations are most densely interconnected. Finally, we compared the present results with synchronized responses in somatosensory (SI) barrel cortex that were evoked by controlled, pulsatile whisker movements in a previous study. We conclude that highly-controlled whisker stimulation increases stimulus coordination and may exaggerate the incidence and strength of synchronization among neurons in the granular or supragranular layers. [ABSTRACT FROM AUTHOR]

We used cross-correlation analysis to characterize the coordination of stimulus-induced neuronal activity in the primary somatosensory barrel cortex of isoflurane-anesthetized rats. On each trial, multiple whiskers were simultaneously deflected at frequencies that corresponded to 2, 5, 8, or 11 Hz. Among 476 neuron pairs that we examined, 342 (71.8%) displayed significant peaks of synchronized activity that exceeded the 99.9% confidence limits. The incidence and strength of these functional associations varied across different cortical layers. Only 52.9% of neuron pairs in layer IV displayed synchronized responses, whereas 84.1% of the infragranular neuron pairs were synchronized during whisker stimulation. Neuronal synchronization was strongest in the infragranular layers, weakest in layer IV, and varied according to the columnar configuration of the neuron pairs. Thus correlation coefficients were largest for neuron pairs in the same whisker barrel row but were smallest for neurons in different rows and arcs. Spontaneous activity in the infragranular layers was also synchronized to a greater degree than in the other layers. Although infragranular neuron pairs displayed similar amounts of synchronization in response to each stimulus frequency, granular and supragranular neurons were synchronized mainly during stimulation at 2 or 5 Hz. These results are consistent with previous studies indicating that infragranular neurons have intrinsic properties that facilitate synchronized activity, and they suggest that neuronal synchronization plays an important role in transmitting sensory information to other cortical or subcortical brain regions. [ABSTRACT FROM AUTHOR]

Elucidating the central sensory projection pathways of extra- and intracranial vessels appears to be of fundamental importance for understanding the pathogenetic mechanisms of primary headaches. In this paper, two kinds of tracers, choleragenoid (cholera toxin subunit b, CTb) and wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP), were used to transganglionically label the central sensory projections of the innervation of the superficial temporal artery (STA). Following either of the tracers applied on the adventitia of the STA, labelled terminations were found mainly in the ipsilateral C1–C3 spinal dorsal horns. Sparse labelling was also found in the interpolar and caudal parts of the spinal trigeminal nucleus. In the spinal cord, CTb labelled profiles were mainly located in laminae III and IV, whereas WGA-HRP labelled profiles were mainly located in laminae I and II. In the medulla, CTb but not WGA-HRP labelled terminals were found in a small dorsolateral extension of the cuneate nucleus. The present results indicate that the primary sensory nervous center of the STA is located in the rostral cervical spinal dorsal horn. The caudal parts of the spinal trigeminal nucleus, which has been demonstrated as a center of pain and temperature sensations of the head and face, transmits limited information from the STA to higher nervous centers. [Copyright &y& Elsevier]

To elucidate the organization of the ferret spinocervicothalamic pathway (SCTP), we examined the lateral cervical nucleus (LCN) and the termination of the cervicothalamic tract (CTT) in this species. In thionin-stained sections, the ferret LCN appeared as an easily delineated column of cells in the dorsolateral funiculus from about mid-C3 to the rostral end of C1, with most cells located in the C1 and C2 segments. In transverse sections, the LCN was elongated along a dorsolateral to ventromedial axis and in the rostral half of C2 and caudal half of C1 continuous with the neck of the dorsal horn. The number of ferret LCN cells was estimated to 2,500–3,700, with an average of 3,340. Substance P-like immunoreactive fibers located preferentially in the ventromedial part of the LCN, whereas serotonin-like immunoreactive fibers were found throughout the nucleus. Anterograde transport of wheat germ agglutinin–horseradish peroxidase conjugate and biotinylated dextran amine demonstrated that the ferret CTT terminates extensively in the peripheral parts of the ventral posterior lateral nucleus. Sparser termination was evident in the ventral posterior inferior nucleus, in the medial nucleus of the posterior complex, and in the medial part of the magnocellular medial geniculate nucleus. Thus, although the LCN is significantly smaller in ferrets than in cats and raccoons, the organization of the LCN and of the cervicothalamic tract is closely similar in the three species. These findings indicate a conserved general organization of the SCTP among carnivores. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI) stands as a prominent global cause of disability, with motor deficits being a common consequence. Despite its widespread impact, the precise pathological mechanisms underlying motor deficits after TBI remain elusive. In this study, hindlimb postural asymmetry (HL-PA) development in rats subjected to focal TBI was investigated to explore the potential roles of collagen IV and laminin within the extracellular matrix (ECM) of selected hindlimb muscles in the emergence of motor deficits following TBI. A focal TBI was induced by ablating the left sensorimotor cortex in rats and motor deficits were assessed by measuring HL-PA. The expression of laminin and collagen IV in eight selected muscles on each side of the hindlimbs from both TBI- and sham-operated rats were studied using immunohistochemistry and semi-quantitatively analyzed. The results indicated that the TBI rats exhibited HL-PA, characterized by flexion of the contralateral (right) hindlimb. In the sham-operated rats, the immunoreactive components of laminin and collagen IV were evenly and smoothly distributed along the border of the muscle fibers in all the investigated muscles. In contrast, in the TBI rats, the pattern was broken into aggregated, granule-like, immunoreactive components. Such a labeling pattern was detected in all the investigated muscles both from the contra- and ipsilateral sides of the TBI rats. However, in TBI rats, most of the muscles from the contralateral hindlimb showed a significantly increased expression of these two proteins in comparison with those from the ipsilateral hindlimb. In comparison to sham-operated rats, there was a significant increase in laminin and collagen IV expression in various contralateral hindlimb muscles in the TBI rats. These findings suggest potential implications of laminin and collagen IV in the development of motor deficits following a focal TBI. [ABSTRACT FROM AUTHOR]

• Spectrum consistency, which means that changes in spectral direction are always a smooth function, is first investigated in the fusion model. • Spatial adaptivity is also introduced to reduce spectral distortion in the fusion process. • The separable approximation method and augmented Lagrangian method are employed to solve the optimization problem. • Our method is compared with other state-of-the-art fusion algorithms, and good performance is verified by UAV datasets. • Furthermore, we apply our fusion algorithm in the application of a vegetation phenotype, which proves its significant research value in UAV remote sensing. Unmanned aerial vehicle (UAV) remote sensing has been widely used in vegetation phenotypes and precision agriculture. The fusion of UAV multispectral and panchromatic images has considerable research value. For example, an accurate vegetation index can be obtained. However, large geometrical distortions are observed in UAV images, contributing to the insufficiency of existing fusion algorithms. Spectrum consistency, which indicates that changes in spectral direction are always a smooth function, is investigated in this paper to solve the above problem. Spatial adaptivity is also introduced to reduce spectral distortion in the fusion process. Based on the two aspects, a multispectral and panchromatic image fusion model employing adaptive spectral-spatial gradient sparse regularization is proposed for UAV remote sensing. The separable approximation and augmented Lagrangian methods are employed to optimize this model. In the experiments, the proposed method is firstly compared with other state-of-the-art fusion algorithms, and good performance is verified by UAV datasets in terms of visual effect and objective quality analysis. Secondly, the fusion algorithm is applied in the application of a vegetation phenotype. The experiments finally demonstrate that accurate vegetation indices can be generated by adopting the proposed algorithm. This finding proves the substantial research value of the proposed algorithm in UAV remote sensing. [ABSTRACT FROM AUTHOR]

Conventional Gas Chromatography‐Mass Spectrometry (GC‐MS) methods for the analysis of ignitable liquids (ILs) are usually time‐consuming, and the data produced are difficult to interpret. A fast IL screening method using direct analysis in real time mass spectrometry (DART‐MS) is proposed in this study. GC‐MS, QuickStrip DART‐MS, and thermal desorption DART‐MS methods were used to analyze neat ILs and thermal desorption DART‐MS without extraction was used to analyze ILs on five substrates (e.g., carpet, wood, cloth, sand, and paper). Compared to GC‐MS, DART‐MS methods generated different spectral profiles for neat ILs with more peaks in the higher mass range and also provided better detection of less volatile compounds. ILs on substrates were successfully classified (98 ± 1%) using partial least squares discriminant analysis (PLS‐DA) models based on thermal desorption DART‐MS data. This study shows that DART‐MS has great potential for the high‐throughput screening of ILs on substrates. [ABSTRACT FROM AUTHOR]

Cerebrospinal fluid contacting neurons (CSF-cNs) are a specific type of neurons located around the ventricles in the brain and the central canal in the spinal cord and have been demonstrated to be intrinsic sensory neurons in the central nervous system. One of the important channels responsible for the sensory function is the polycystic kidney disease 2-like 1 (PKD2L1) channel. Most of the studies concerning the distribution and function of the PKD2L1-expressing CSF-cNs in the spinal cord have previously been performed in non-mammalian vertebrates. In the present study immunohistochemistry was performed to determine the distribution of PKD2L1-immunoreactive (IR) CSF-cNs in the spinal cords of four mammalian species: mouse, rat, cat, and macaque monkey. Here, we found that PKD2L1-expressing CSF-cNs were present at all levels of the spinal cord in these animal species. Although the distribution pattern was similar across these species, differences existed. Mice and rats presented a clear PKD2L1-IR cell body labeling, whereas in cats and macaques the PKD2L1-IR cell bodies were more weakly labeled. Ectopic PKD2L1-IR neurons away from the ependymal layer were observed in all the animal species although the abundance and the detailed locations varied. The apical dendritic protrusions with ciliated fibers were clearly seen in the lumen of the central canal in all the animal species, but the sizes of protrusion bulbs were different among the species. PKD2L1-IR cell bodies/dendrites were co-expressed with doublecortin, MAP2 (microtubule-associated protein 2), and aromatic L-amino acid decarboxylase, but not with NeuN (neuronal nuclear protein), indicating their immature properties and ability to synthesize monoamine transmitters. In addition, in situ hybridization performed in rats revealed PKD2L1 mRNA expression in the cells around the central canal. Our results indicate that the intrinsic sensory neurons are conserved across non-mammalian and mammalian vertebrates. The similar morphology of the dendritic bulbs with ciliated fibers (probably representing stereocilia and kinocilia) protruding into the central canal across different animal species supports the notion that PKD2L1 is a chemo- and mechanical sensory channel that responds to mechanical stimulations and maintains homeostasis of the spinal cord. However, the differences of PKD2L1 distribution and expression between the species suggest that PKD2L1-expressing neurons may receive and process sensory signals differently in different animal species. [ABSTRACT FROM AUTHOR]

Improving the performance of fuel cell is a research focus. The rough interface between microporous layer (MPL) and catalyst layer (CL) which affects the performance of fuel cell has been simulated by W-M function. The relative heat resistance and the relative diffusivity of the rough contact surface to the perfect contact surface between MPL and CL had been calculated by Monte Carlo simulation. The results show that the relative thermal resistance and the relative diffusivity decrease with the increment of fractal dimension of rough surface. The research results have reference value for fuel cell design. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "Evaluation of Mass Spectrometric Methods for Screening Polycyclic Aromatic Hydrocarbons in the Particulate Phase of Wildfire/Biomass Smoke." The original article was published without open access on October 27, 2022, but the authors later decided to make it available under a Creative Commons Attribution 4.0 International License. This license allows for the use, sharing, adaptation, distribution, and reproduction of the article as long as appropriate credit is given to the original authors and source. The correction notice confirms that the original article has been corrected. [Extracted from the article]

The flowers of daylily ( Hemerocallis fulva (L.) L.) are called ' Jinzhen' which are commonly used as vegetables or seasoning in East Asia. In this study, we evaluated the chemical profile changes with different processing method after harvest. Five different drying methods including solar drying, vacuum freeze drying, steam drying, and hot air drying method were investigated regarding their impact on the chemical constituents in daylily. The major phenolic compounds were tentatively characterized with ultra-high performance liquid chromatography tandem high-resolution mass spectrometric with multistage fragmentation techniques (UHPLC-HRMSn). The UHPLC-UV fingerprinting and UHPLC-HRMSn-based metabolomic approaches were used for identifying the difference between different processing methods. The quercetin 3- O-rutinoside, 5- O-caffeoylquinic acids are obviously higher in freeze-dried and steam-dried samples. Colchicine was believed to be one of the toxic constituents found in daylily fresh flowers; however, no colchicine was found in any the daylily samples investigated. Practical applications The drying process is particularly important for handling and distribution of daylily flowers after harvest and it can also prolong the shelf life. However, the drying process may result in degradation of nutrients and quality loss in food. Steamed sunlight dried or hot air drying methods preserve most of the phenolic composition of fresh daylily samples. The purpose of this study was to analyze the phenolic compounds in daylily using ultra-high performance liquid chromatography tandem high-resolution mass spectrometric with multistage fragmentation techniques and to evaluate the drying processing method by fingerprinting and metabolomic approaches. [ABSTRACT FROM AUTHOR]

A comprehensive characterization of C-glycosyl flavones in wheat germ has been conducted using multi-stage high resolution mass spectrometry (HRMSn) in combination with a mass defect filtering (MDF) technique. MDF performed the initial search of raw data with defined C-glycosyl flavone mass windows and mass defect windows to generate the noise-reduced data focusing on targeted flavonoids. The high specificity of the exact mass measurement permits the unambiguous discrimination of acyl groups (nominal masses of 146, 162 and 176.) from sugar moieties (rhamnose, glucose or galactose and glucuronic acid). A total of 72 flavone C-glycosyl derivatives, including 2 mono-C-glycosides, 34 di-C-glycosides, 15 tri-glycosides, 14 acyl di-C-glycosides and 7 acyl tri-glycosides, were characterized in wheat germ, some of which were considered to be important marker compounds for differentiation of whole grain and refined wheat products. The 7 acylated mono-O-glycosyl-di-C-glycosyl flavones and some acylated di-C-glycosyl flavones are reported in wheat for the first time. The frequent occurrence of numerous isomers is a remarkable feature of wheat germ flavones. Both UV and mass spectra are needed to maximize the structure information obtained for data interpretation. [ABSTRACT FROM AUTHOR]

American ginseng (Panax quinquefolius L.) has been recognized as a valuable herb medicine, and ginsenosides are the most important components responsible for the health-beneficial effects. This study investigated the secondary metabolites responsible for the differentiation of wild and cultivated American ginsengs with ultrahigh-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS)-based metabolomic approach. An in-house ginsenoside library was developed to facilitate data processing and metabolite identification. Data visualization methods, such as heatmaps and volcano plots, were utilized to extract discriminated ion features. The results suggested that the ginsenoside profiles of wild and cultivated ginsengs were significantly different. The octillol (OT)-type ginsenosides were present in greater abundance and diversity in wild American ginsengs; however, a wider distribution of the protopanaxadiol (PPD)-and oleanolic acid (OA)-type ginsenosides were found in cultivated American ginseng. Based on the tentative identification and semi-quantification, the amounts of five ginsenosides (i.e., notoginsenoside H, glucoginsenoside Rf, notoginsenoside R1, pseudoginsenoside RT2, and ginsenoside Rc) were 2.3–54.5 fold greater in wild ginseng in comparison to those in their cultivated counterparts, and the content of six ginsenosides (chicusetsusaponin IVa, malonylginsenoside Rd, pseudoginsenoside Rc1, malonylfloralginsenoside Rd6, Ginsenoside Rd, and malonylginsenoside Rb1) was 2.6–14.4 fold greater in cultivated ginseng compared to wild ginseng. The results suggested that the in-house metabolite library can significantly reduce the complexity of the data processing for ginseng samples, and UHPLC-HRMS is effective and robust for identifying characteristic components (marker compounds) for distinguishing wild and cultivated American ginseng. [ABSTRACT FROM AUTHOR]

• The structural impact on anthocyanins' UV–Vis molar absorptivity was studied; • A quantitative strategy based on the molar relative response factors was proposed; • An online database for 617 anthocyanins was developed to support the approach; • Our strategy provided improved quantitative results for anthocyanins in food. The effects of anthocyanin's substitution groups on the UV–Vis molar absorptivity were examined by analyzing a group of 31 anthocyanidin/anthocyanin reference standards with ultra-high performance liquid chromatography-diode array detector (UHPLC-DAD). The substitution groups on aglycones were found to associate with molar absorptivity variations, often neglected in anthocyanin quantitation, resulting in significant analytical errors. A simple yet comprehensive strategy based on the molar relative response factors (MRRFs) and a single master reference calibration (i.e., cyanidin-3-glucoside) was proposed to quantify anthocyanins in red cabbage, blueberry, and strawberry samples with improved analytical accuracy. The results indicate this approach provides an effective, inexpensive, and accurate analytical method for anthocyanins in food materials without using individual reference standards. MRRFs of 617 anthocyanins/anthocyanidins were calculated, and the information is freely available at https://BotanicalDC.online/anthocyanin/. This study could be critical to developing new reference methods for anthocyanin analysis and harmonizing results and data from various sources. [ABSTRACT FROM AUTHOR]

Brain injury and stroke are leading causes of adult disability. Motor deficits are common problems, and their underlying pathological mechanisms remain poorly understood. The serotoninergic system is implicated in both functional recovery from and the occurrence of spasticity after injuries to the central nervous system. This study, which was conducted on rats, investigated the development of limb postural changes and their relationship to the expression of serotonin (5-HT) 2A and 2C receptors in the spinal cord in the 4 weeks after focal traumatic brain injury (TBI) to the right hindlimb sensorimotor cortex. The limb motor deficits were assessed by measuring gait pattern changes during walking and hindlimb postural asymmetry at different time intervals (3–28 days) after surgery. The expressions of the 5-HT2A and 2C receptors in the lumbar spinal cord were investigated using immunohistochemistry. The results showed that all the rats with TBI, independently of the duration of the interval, displayed postural asymmetry with flexion on the contralateral (left) side (>2 mm), while the sham-operated rats showed no apparent postural asymmetry. The TBI rats also had longer stride lengths during walking in both their hindlimbs and their forelimbs compared with the sham rats. For both the TBI and the sham rats, the hind-paw placement angles were larger on the contralateral side in some of the groups. Compared to the sham-operated rats, the 5-HT2A and 2C receptor expression did not significantly change on either side of the lumbar spinal cords of the TBI rats in any of the groups. These results suggest that focal TBI can induce motor deficits lasting a relatively long time, and that these deficits are not related to the expression of the 5-HT2A and 2C receptors in the spinal cord. [ABSTRACT FROM AUTHOR]

Predictive and prognostic biomarkers for multiple sclerosis (MS) remain a significant gap in MS diagnosis and treatment monitoring. Currently, there are no timely markers to diagnose the transition to secondary progressive MS (SPMS). This study aims to evaluate the discriminatory potential of the High temperature requirement serine protease (HTRA1)/Macrophage migration inhibitory factor (MIF) cerebrospinal fluid (CSF) ratio in distinguishing relapsing-remitting (RRMS) patients from SPMS patients. The MIF and HTRA1 CSF levels were determined using ELISA in healthy controls (n = 23), RRMS patients before (n = 22) and after 1 year of dimethyl fumarate treatment (n = 11), as well as in SPMS patients before (n = 11) and after 2 years of mitoxantrone treatment (n = 7). The ability of the HTRA1/MIF ratio to discriminate the different groups was determined using receiver operating curve (ROC) analyses. The ratio was significantly increased in treatment naïve RRMS patients while decreased again in SPMS patients at baseline. Systemic administrated disease modifying treatment (DMT) only significantly affected the ratio in RRMS patients. ROC analysis demonstrated that the ratio could discriminate treatment naïve RRMS patients from SPMS patients with 91% sensitivity and 100% specificity. The HTRA1/MIF ratio is a strong candidate as a MS biomarker for SPMS conversion. • HTRA1/MIF ratio is a strong candidate as a biomarker for RRMS to SPMS conversion. • The HTRA1/MIF ratio, initially high in RRNMS, decreases with 1-year DMF treatment. • The HTRA1/MIF ratio decreases with disease progression to SPMS, indicating a shift from RRMS inflammation. • MTX treatment has limited impact on HTRA1/MIF CSF ratio in SPMS patients. • Combining HTRA1 and MIF improves prognostic accuracy over individual markers. [ABSTRACT FROM AUTHOR]

Abstract: A rapid and sensitive bioassay based on liquid chromatography–tandem mass spectrometry (LC–MS/MS) for the simultaneous determination of four isomeric escin saponins (escin Ia, escin Ib, isoescin Ia and isoescin Ib) in human plasma has been developed and validated. Sample preparation of plasma after addition of telmisartan as internal standard (I.S.) involved solid-phase extraction (SPE) on C18 cartridges. Separation was based on reversed phase chromatography using gradient elution with methanol–acetonitrile (50:50, v/v) and 10mM ammonium acetate solution (pH 6.8). MS/MS detection in the positive ion mode used multiple reaction monitoring of the transition at m/z 1113.8→807.6. Stability issues with the four saponins required the addition of formic acid to plasma samples prior to storage at −80°C and analysis within 30 days. The method was linear at concentrations up to 10ng/mL with correlation coefficients>0.996 for all analytes. The lower limit of quantitation (LLOQ) for all four saponins was 33pg/mL. Intra- and inter-day precisions (as relative standard deviation) were all <15% and accuracies (as relative error) in the range −5.3% to 6.1%. The method was successfully applied to a pharmacokinetic study of escins in healthy volunteers after oral administration of sodium aescinate tablets containing 60mg escin saponins. [Copyright &y& Elsevier]

Background: High Temperature Requirement Serine Protease A1 (HTRA1) degrades extracellular matrix molecules (ECMs) and growth factors. It interacts with several proteins implicated in multiple sclerosis (MS), but has not previously been linked to the disease. Objective: Investigate the levels of HTRA1 in cerebrospinal fluid (CSF) in different subtypes of MS and brain tissue. Methods: Using ELISA, HTRA1 levels were compared in CSF from untreated patients with relapsing–remitting MS (RRMS, n = 23), secondary progressive MS (SPMS, n = 26) and healthy controls (HCs, n = 26). The effect of disease modifying therapies (DMTs) were examined in both patient groups. Cellular distribution in human brain was studied using immunochemistry and the oligointernode database, based on a single-nuclei RNA expression map. Results: HTRA1 increased in RRMS and SPMS compared to HCs. DMT decreased HTRA1 levels in both types of MS. Using ROC analysis, HTRA1 cut-offs could discriminate HCs from RRMS patients with 100% specificity and 82.6% sensitivity. In the brain, HTRA1 was expressed in glia and neurons. Conclusion: HTRA1 is a promising CSF biomarker for MS correlating with disease- and disability progression. Most cell species of the normal and diseased CNS express HTRA1 and the expression pattern could reflect pathological processes involved in MS pathogenesis. [ABSTRACT FROM AUTHOR]

Traumatic brain injury and stroke result in hemiplegia, hemiparesis, and asymmetry in posture. The effects are mostly contralateral; however, ipsilesional deficits may also develop. We here examined whether ablation brain injury and controlled cortical impact (CCI), a rat model of clinical focal traumatic brain injury, both centered over the left or right sensorimotor cortex, induced hindlimb postural asymmetry (HL-PA) with contralesional or ipsilesional limb flexion. The contralesional hindlimb was flexed after left or right side ablation injury. In contrast, both the left and right CCI unexpectedly produced HL-PA with flexion on left side. The flexion persisted after complete spinal cord transection suggesting that CCI triggered neuroplastic processes in lumbar neural circuits enabling asymmetric muscle contraction. Left limb flexion was exhibited under pentobarbital anesthesia. However, under ketamine anesthesia, the body of the left and right CCI rats bent laterally in the coronal plane to the ipsilesional side suggesting that the left and right injury engaged mirror-symmetrical motor pathways. Thus, the effects of the left and right CCI on HL-PA were not mirror-symmetrical in contrast to those of the ablation brain injury, and to the left and right CCI produced body bending. Ipsilateral effects of the left CCI on HL-PA may be mediated by a lateralized motor pathway that is not affected by the left ablation injury. Alternatively, the left-side-specific neurohormonal mechanism that signals from injured brain to spinal cord may be activated by both the left and right CCI but not by ablation injury. [ABSTRACT FROM AUTHOR]

Effects of environmental factors may be transmitted to the following generation, and cause neuropsychiatric disorders including depression, anxiety, and posttraumatic stress disorder in the offspring. Enhanced synaptic plasticity induced by environmental enrichment may be also transmitted. We here test the hypothesis that the effects of brain injury in pregnant animals may produce neurological deficits in the offspring. Unilateral brain injury (UBI) by ablation of the hindlimb sensorimotor cortex in pregnant rats resulted in the development of hindlimb postural asymmetry (HL‐PA), and impairment of balance and coordination in beam walking test in the offspring. The offspring of rats with the left UBI exhibited HL‐PA before and after spinal cord transection with the contralesional (i.e., right) hindlimb flexion. The right UBI caused the offspring to develop HL‐PA that however was cryptic and not‐lateralized; it was evident only after spinalization, and was characterized by similar occurrence of the ipsi‐ and contralesional hindlimb flexion. The HL‐PA persisted after spinalization suggesting that the asymmetry was encoded in lumbar spinal neurocircuits that control hindlimb muscles. Balance and coordination were affected by the right UBI but not the left UBI. Thus, the effects of a unilateral brain lesion in pregnant animals may be intergenerationally transmitted, and this process may depend on the side of brain injury. The results suggest the existence of left‐right side‐specific mechanisms that mediate transmission of the lateralized effects of brain trauma from mother to fetus. [ABSTRACT FROM AUTHOR]

BACKGROUND: The new approach of using UV-C irradiation followed by a specific dark period to control plant diseases has the potential to become a mainstream treatment in the production of strawberries and other fruits and vegetables. Thus, it is imperative to study the effects of this treatment on fruit quality. METHODS: In this study, short-day 'Chandler' strawberry plants grown in growth chamber from bloom to harvest were irradiated twice a week with nighttime UV-C light (253 nm peak value 12.36 J m–2 and the total dose of 50 J m–2 in the range of 240 –260 nm). The effects on the content of key phenolic compounds in mature fruit were studied with targeted analysis and a non-targeted metabolomic approach based on ultra-high performance liquid chromatography high resolution mass spectrometry (UHPLC-HRMS). Analysis of variance-principal component analysis (ANOVA-PCA) was used to associate variance with different experimental factors. RESULTS: Results indicate that the content of anthocyanins, glucosides and glucuronides of quercetin and kaempferol, catechin, pelargonidin rutinoside, and ellagic acid was not affected by UV-C treatment. ANOVA-PCA analysis of the metabolomic dataset showed no significant differences in composition and content of strawberry metabolites between UV-C and control groups; however, differences were observed between harvest times. CONCLUSIONS: Our findings strongly indicate that UV-C treatment of 50 J/m2 twice per week did not affect nutritional values of strawberry fruit. The metabolomic approach combined with ANOVA-PCA used to evaluate strawberry fruit quality after UV-C irradiation proved to be a very powerful tool in providing an overall insight into fruit quality and accurately determines the influence of each experimental factor. [ABSTRACT FROM AUTHOR]

Cannabis has been cultivated as a source of food, fiber, and medicine globally, so the classification of Cannabis cultivars based on their chemical fingerprints is important to standardize and control the quality of Cannabis, ensure that patients receive a full and consistent spectrum of therapeutic benefits, and promote the further implementation of Cannabis-based products in clinical uses. In this study, a high-throughput analytical method, thermal desorption direct analysis in real time mass spectrometry (TD-DART-MS), was employed to classify various Cannabis hemp cultivars with multivariate analysis. Cannabis plant materials from four cultivars were analyzed directly by TD-DART-MS without solvent extraction. The total run time was 15 min including 8 min for data acquisition and 7 min for cooling down the thermal stage. Data preprocessing strategy such as data transformation was evaluated on the TD-DART-MS data set and cubic root transform has shown significant improvement to the classification. TD-DART-MS data was then processed by principal component analysis (PCA) and the results were compared with those from liquid chromatography-mass spectrometry (LC-MS) data. The samples were clustered based on cultivars by PCA, and the validation samples collected 2 months later were also grouped together with the original samples by cultivars after mean-centering the data sets. Partial least squares discriminant analysis (PLS-DA) models were constructed with the TD-DART-MS data sets and a 99.3 ± 0.3% classification accuracy was obtained from 100 independent bootstrapped Latin partition evaluations. Our results indicate that TD-DART-MS may be used as a screening tool for the classification of Cannabis cultivars. [ABSTRACT FROM AUTHOR]

The covalent attachment of polyethylene glycol (PEG) to therapeutic compounds (known as PEGylation) is one of the most promising techniques to improve the biological efficacy of small molecular weight drugs. After administration, PEGylated prodrugs can be metabolized into pharmacologically active compounds so that PEGylated drug, free drug and released PEG are present simultaneously in the body. Understanding the pharmacokinetic behavior of these three compounds is needed to guide the development of pegylated theranostic agents. However, PEGs are polydisperse molecules with a wide range of molecular weights, so that the simultaneous quantitation of PEGs and PEGylated molecules in biological matrices is very challenging. This article reports the application of a data-independent acquisition method (MSAll) based on liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-q-q-TOF-MS) in the positive ion mode to the simultaneous determination of methoxyPEG2000-doxorubicin (mPEG2K-Dox) and its breakdown products in rat blood. Using the MSAll technique, precursor ions of all molecules are generated in q1, fragmented to product ions in q2 (collision cell), and subjected to TOF separation before precursor and product ions are recorded using low and high collision energies (CE) respectively in different experiments for a single sample injection. In this study, dissociation in q2 generated a series of high resolution PEG-related product ions at m/z 89.0611, 133.0869, 177.1102, 221.1366, 265.1622, 309.1878, and 353.2108 corresponding to fragments containing various numbers of ethylene oxide subunits, Dox-related product ions at m/z 321.0838 and 361.0785, and an mPEG2K-Dox specific product ion at m/z 365.0735. Detection of mPEGs and mPEG2K-Dox was based on high resolution extracted ions of mPEG and the specific compound. The method was successfully applied to a pharmacokinetic study of doxorubicin, mPEG2K (methylated polyethylene glycol 2K), and mPEG2K-doxorubicin in rats after a single intravenous injection of mPEG2K-doxorubicin. To the best of our knowledge, this is the first assay that simultaneously determines mPEG, Dox, and mPEG2K-Dox in a biological matrix. We believe the MSAll technique as applied in this study can be potentially extended to the determination of other PEGylated small molecules or polymeric compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • SCC mechanism of α-Fe under SCW is revealed at atomic scale. • There is no significant difference in corrosion under a stress below threshold. • The stability of vacancy-H clusters promotes defects formation in GB. • Vacancies in GB accelerate intergranular corrosion, resulting in materials failure. Mechanistically understanding stress corrosion cracking (SCC) of Fe-based alloy under extremely high-temperature and high-pressure conditions is a key challenge for designing and optimizing structural materials of the supercritical water (SCW) reactors. The mechanism of SCC of α-Fe in supercritical water has been investigated by reactive force-field molecular dynamics simulations, and it is obtained that SCC is caused by the coupling effect of hydrogen embrittlement and intergranular corrosion. Hydrogen atoms in metals induce vacancy formation when the loaded stress is larger than the threshold stress, resulting in forming stable vacancy-hydrogen clusters. These stable vacancies pin grain boundary (GB) and act as stress concentrators under sufficient tensile stress, leading to the generation of more vacancies. A large number of vacancies in GB promote intergranular corrosion which directly results in materials failure. [ABSTRACT FROM AUTHOR]

Due to the complexity and variation of the chemical constituents in authentic black cohosh ( Actaea racemosa) and its potential adulterant species, an accurate and feasible method for black cohosh authentication is not easy. A high-resolution accurate mass (HRAM) LC-MS fingerprinting method combined with chemometric approach was employed to discover new marker compounds. Seven hydroxycinnamic acid amide (HCAA) glycosides are proposed as potential marker compounds for differentiation of black cohosh from related species, including two Asian species ( A. foetida, A. dahurica) and two American species ( A. pachypoda, A. podocarpa). These markers were putatively identified by comparing their mass spectral fragmentation behavior with those of their authentic aglycone compounds and phytochemistry reports. Two isomers of feruloyl methyldopamine 4- O-hexoside ([M + H] 506) and one feruloyl tyramine 4- O-hexoside ([M + H] 476) contributed significantly to the separation of Asian species in principle component analysis (PCA) score plot. The efficacy of the models built on four reasonable combinations of these markers in differentiating black cohosh and its adulterants were evaluated and validated by partial least-square discriminant analysis (PLS-DA). Two models based on these reduced dataset achieved 100% accuracy based on the current sample collection, including the model that used only three feruloyl dopamine- O-hexoside isomers ([M + H] 492) and one feruloyl dopamine- O-dihexoside ([M + H-hexosyl] at m/ z 492). [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) are a class of compounds containing multiple aromatic rings formed during incomplete combustion. Since many of them are known mutagens and carcinogens, PAHs found in the particulate matter (PM) from the wildfire smoke may pose significant health risks to the wildland firefighters. It is pivotal to determine the levels of PAHs in the PM to evaluate the health effects of their inhalation exposure. However, the determination of PAHs using the conventional chromatographic approaches is often time-consuming and laborious. Herein, we describe a novel method for screening nonpolar and polar PAHs in the PM of smoke by direct analysis in real-time mass spectrometry (DART-MS). PM2.5 and PM10 samples were collected on the quartz filters with a sampling system consisting of a cascade impactor with a portable sampling pump. Various indoor and outdoor experiments from biomass burns were conducted to evaluate the PM sampling systems. PAHs were analyzed by DART-MS and gas chromatography-mass spectrometry (GC–MS) methods. The PM samples were collected in California during the wildfire season of fall 2020, and significant levels of multiple nonpolar PAHs and polar PAHs were detected. Overall, the DART-MS method has shown promising ability for high-throughput screening of PAHs in the PM of smoke. Further studies are currently under way to apply this method to study the particulate phase PAH exposures of wildland firefighters during their firefighting activities. [ABSTRACT FROM AUTHOR]

Macrophage migration inhibitory factor (MIF) is involved in the function of both the innate and adaptive immune systems and in neuroprotection and has recently been implicated in multiple sclerosis (MS). Determination of MIF levels in the cerebrospinal fluid (CSF) of patients with distinct subtypes of MS and the cellular localization of MIF in human brain tissue. The levels of MIF were investigated in CSF from patients with clinically isolated syndrome (CIS) (n = 26), relapsing-remitting MS (RRMS) (n = 22), secondary progressive MS (SPMS) (n = 19), and healthy controls (HCs) (n = 24), using ELISA. The effect of disease-modifying therapies in the RRMS and SPMS cohorts were examined. Cellular distribution of MIF in the human brain was studied using immunochemistry and the newly available OligoInternode database. MIF was significantly decreased in treatment-naïve CIS and RRMS patients compared to HCs but was elevated in SPMS. Interestingly, MIF levels were sex-dependent and significantly lower in women with CIS and RRMS. MIF expression in the human brain was localized to neurons, astrocytes, pericytes, and oligo5 oligodendrocytes but not in microglia. The finding that MIF was decreased in newly diagnosed CIS and RRMS patients but was high in patients with SPMS may suggest that MIF levels in CSF are regulated by local MIF receptor expression that affects the overall MIF signaling in the brain and may represent a protective mechanism that eventually fails. • MIF CSF levels are reduced during CIS and early RRMS while increased in SPMS. • MIF levels may be sex-dependent in CIS and RRMS patients. • MIF is highly expressed by neurons in the human brain. • MIF levels in MS may reflect dysregulated MIF signaling in the CNS. • MIF is a good prognostic marker for disease progression in MS. [ABSTRACT FROM AUTHOR]

Neuromodulators, such as serotonin (5-hydroxytryptamine, 5-HT) and noradrenalin, play an essential role in regulating the motor and sensory functions in the spinal cord. We have previously shown that in the rat spinal cord the activity of aromatic L-amino acid decarboxylase (AADC) cells to produce 5-HT from its precursor (5-hydroxytryptophan, 5-HTP) is dramatically increased following complete spinal cord transection. In this study, we investigated whether a partial loss of 5-HT innervation could similarly increase AADC activity. Adult rats with spinal cord hemisected at thoracic level (T11/T12) were used with a postoperation interval at 5 days or 60 days. Using immunohistochemistry, first, we observed a significant reduction in the density of 5-HT-immunoreactive fibers in the spinal cord below the lesion on the injured side for both groups. Second, we found that the AADC cells were similarly expressed on both injured and uninjured sides in both groups. Third, increased production of 5-HT in AADC cells following 5-HTP was seen in 5-day but not in 60-day postinjury group. These results suggest that plastic changes of the 5-HT system might happen primarily in the subchronic phase and for longer period its function could be compensated by plastic changes of other intrinsic and/or supraspinal modulation systems. [ABSTRACT FROM AUTHOR]

Neurons of the dorsal spinocerebellar tracts (DSCT) have been described to be rhythmically active during walking on a treadmill in decerebrate cats, but this activity ceased following deafferentation of the hindlimb. This observation supported the hypothesis that DSCT neurons primarily relay the activity of hindlimb afferents during locomotion, but lack input from the spinal central pattern generator. The ventral spinocerebellar tract (VSCT) neurons, on the other hand, were found to be active during actual locomotion (on a treadmill) even after deafferentation, as well as during fictive locomotion (without phasic afferent feedback). In this study, we compared the activity of DSCT and VSCT neurons during fictive rhythmic motor behaviors. We used decerebrate cat preparations in which fictive motor tasks can be evoked while the animal is paralyzed and there is no rhythmic sensory input from hindlimb nerves. Spinocerebellar tract cells with cell bodies located in the lumbar segments were identified by electrophysiological techniques and examined by extra- and intracellular microelectrode recordings. During fictive locomotion, 57/81 DSCT and 30/30 VSCT neurons showed phasic, cycle-related activity. During fictive scratch, 19/29 DSCT neurons showed activity related to the scratch cycle. We provide evidence for the first time that locomotor and scratch drive potentials are present not only in VSCT, but also in the majority of DSCT neurons. These results demonstrate that both spinocerebellar tracts receive input from the central pattern generator circuitry, often sufficient to elicit firing in the absence of sensory input. [ABSTRACT FROM AUTHOR]

Abstract: It is well known that spinal motoneurons below a spinal transection become supersensitive to a systemic administration of serotonin (5-HT) precursors, such as 5-hydroxytryptophan. This supersensitivity has been implicated in both the process of functional recovery following chronic lesions, and also in the development of symptoms such as hyperreflexia and spasticity. However, the mechanisms of this denervation supersensitivity are still largely unknown. In this study we have investigated the changes in 5-HT2A receptor immunoreactivity following chronic spinal transections at the level of the sacrocaudal spinal cord. The results show that in the spinalized rats the immunoreactivity of 5-HT2A receptors below the lesion is dramatically increased in the motoneuron soma and its proximal dendritic territory, most likely also in their distal dendritic territory, to a level 3–5-fold higher than that of sham-operated rats. We also found a small number of intraspinal 5-HT neurons and clusters of 5-HT fibers and their varicosities in the spinal cord caudal to the lesion, which may provide an intrinsic source of 5-HT to act upon the upregulated 5-HT2A receptors. These results indicate that the upregulation of 5-HT2A receptors at least partly underlies the 5-HT denervation supersensitivity of spinal motoneurons after a complete spinal transection. [Copyright &y& Elsevier]

• DART-MS, GC–MS, and LC-MS were used to analyze black pepper samples and their results were compared; • Chemometrics was applied to classify the black pepper samples based on their origins; • DART-MS has been demonstrated as a simple and high-throughput method for discrimination studies of food materials. The current study applied gas chromatography-mass spectrometry (GC–MS), liquid chromatography-mass spectrometry (LC-MS), and thermal desorption direct analysis in real-time mass spectrometry (TD-DART-MS) methods to the analysis of black pepper (Piper nigrum L.) samples from different countries. The black pepper powder samples were analyzed directly by TD-DART-MS without any extraction, but for GC–MS and LC-MS methods, a methanol extraction procedure was employed before the analysis. Various compounds, such as piperamides and terpenes, were detected. Partial least squares-discriminant analysis (PLS-DA) was used to classify black pepper samples based on their origins. Total ion mass spectrum (TMS) data profiles from GC–MS, LC-MS, and TD-DART-MS methods were constructed and evaluated for the performance of classification. A cubic-root data transformation was tested in the data preprocessing and found to be effective for improving the classification rates. The average classification rates of PLS-DA models with GC–MS-cubic-root-TMS, LC-MS-cubic-root-TMS, and DART-MS-cubic-root-TMS data representations were 94.1 ± 0.6%, 87.7 ± 0.6%, and 97.0 ± 0.3% respectively, for 100-time bootstrapped-Latin-partition cross-validation. This study presents for the first time the analysis of plant-based food materials by using TD-DART-MS, and it has been demonstrated as a simple and high-throughput method for classification studies. [ABSTRACT FROM AUTHOR]