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This document summarizes a study on the effects of CFTR modulators on patients with cystic fibrosis (CF) and leukocyte adhesion deficiency type IV (LAD-IV). The study found that CFTR modulators improved certain cellular functions in CF patients, suggesting that they may correct both CF and LAD-IV phenotypes. However, there were some patients who showed improvement in CF symptoms but not in LAD-IV characteristics, indicating the need for further research. The study also suggests that measuring certain cellular markers could be a useful method for monitoring patients in the long term. [Extracted from the article]

The review reports on investigations and studies that have contributed in the last 20 years (2003–2023) to the clarification of the mechanisms governing the chemical vapor generation (CVG) of hydrides and other volatile metallic species using aqueous phase derivatization with tetrahydridoborate (1-)(THB) and amine boranes, which is widely used in determination and speciation analysis of trace elements by atomic optical and mass spectrometry. The discussion begins with the early investigations leading to definition of the mechanism of hydrolysis of aqueous THB and that of reaction conditions. The new knowledge represents important achievements for the clarification of controversial aspects that plagued CVG for more than 35 years and stimulated further studies which are discussed in detail. They concern with the mechanism of hydrolysis of amine boranes, the mechanism of interferences, the role played by chemical additives and the definition of more general reaction models for CVG, which are valid for both analytical and non-analytical reaction conditions. The latest developments and the analytical applications of the new knowledge to trace element analysis are discussed. [ABSTRACT FROM AUTHOR]

This paper reports a summary of the studies on the mechanisms that govern the generation of hydrides and other volatile species through reaction with aqueous boranes (CVG). This derivatization reaction has been used since the early 1970s for elemental determination and speciation from the trace level down to the ultratrace level and below. An IUPAC project, concluded in 2011, reported on the mechanisms of hydrogen transfer from borane to the analytical substrate and served to remove erroneous concepts that had dominated CVG until the early 2000s. Following the conclusion of the IUPAC project, many studies have been published on the mechanisms of CVG under conditions approaching those of analyzes of real samples. These studies included the definition of more general reaction models, which valid under non-analytical conditions, the mechanism of action of additives and interferences in CVG of volatile hydrides. In addition to the analytical utility for CVG, the results represent a contribution to the knowledge of the chemistry of aqueous boranes. Other studies will be necessary to clarify still unknown aspects, among them the identity of volatile transition metal species formed by reaction of metal ions with aqueous boranes. [ABSTRACT FROM AUTHOR]

The negative impact of liquid phase interferences of transition metals has plagued chemical vapor generation with tetrahydridoborate since its introduction, which was more than fifty years ago. Herein, the interference from selected transition metal ions in the generation of SbH3 and BiH3 was investigated using the hydrolysis products of NaBH4-hydridoboron intermediates (BH)-as derivatization reagents instead of NaBH4. The BH intermediates were simply generated on-line in a pre-hydrolysis coil of the instrumental set-up. Compared to NaBH4, the use of BH intermediates allowed for significantly improved tolerance to the interference of Ni(II), Co(II), and Cu(II) (tolerance limit of ≥100 mg L−1) for Bi and Sb determination in the absence of any masking agents and in a wide range of acidity. Their applicability to real complex samples was successfully demonstrated by the determination of Sb and Bi in steel and copper standard reference materials. Beyond the analytical application, this work aims to play a part in the comprehension of borohydride chemical behaviour, which is still not completely understood. [ABSTRACT FROM AUTHOR]

In order to elucidate controversial results emerging in chemical vapor generation (CVG) for trace element determination, we conducted a series of experiments devoted to the identification of intermediates formed by acid hydrolysis of amine-boranes. For the first time, direct analysis in real time coupled with high-resolution mass spectrometry (DART-Orbitrap) was applied for detection of this class of compounds. Mass spectra of both solid amine-boranes and their aqueous solutions (pH ~ 8, no hydrolysis) were acquired for understanding their ionization pathway. Mass spectra of aqueous solutions of t-BuNH2·BH3 and Me2NH·BH3 were acquired under conditions that are employed in CVG (0.017–4.0 mol L−1 HCl, 0.167–0.2 mol L−1 borane reagent). The results disclose a reactivity driven by pH of amine-boranes undergoing hydrolysis. At low acidity, the hydrolysis proceeds according to the currently accepted displacement mechanisms (i.e., R3N·BH3 + H3O+ → R3NH+ + H2OBH3). At higher acidity, N-tert-butyl, cyclotriborazane, and bis(dimethylamino)boronium were identified, for the first time, during the hydrolysis of t-BuNH2·BH3 and Me2NH·BH3, respectively. Formation of these intermediates was ascribed to a hydrolysis pathway starting with the ionization of the amine-borane, (i.e., R3N·BH3 + H3O+ → [(H2O)R3NBH2] + + H2). The new evidence explains the anomalous behavior observed in CVG by amine-borane derivatization, and updates the currently accepted mechanisms for the acid hydrolysis of amine-boranes. Graphical Abstract [ABSTRACT FROM AUTHOR]

The aqueous-phase reaction of dimethylarsinc acid (DMAs(V)) with NaBH4 (THB) was studied under non-analytical conditions (1000 μg/mL As, 0.1 M HCl, 1% NaBH4) with the aim of identifying intermediates and reaction products. The use of direct analysis in real time (DART) with high-resolution mass spectrometry (HRMS), in combination with two different chemical vapor generation systems, allowed the identification of some species not detected by GC-MS such as Me2As–AsMe–AsMe2 and the arsonium species [Me3As–AsMe2]+ and [Me2As–AsMe2–AsMe2]+. Many other methylated species of arsenic containing up to four arsenic atoms have been observed. Unfortunately, the oxidation mechanism that took place in the DART source interfered with the identification of some of those species formed in solution following THB reduction. The species identified by DART-HRMS, together with those previously identified by GC-MS (Me2AsH, Me2AsOH, Me3As, Me3AsO, Me2AsAsMeH, Me2AsAsMe2, and Me2As–O–AsMe2)‚ enabled the formulation of hypotheses on the possible reaction pathways and revealed an aqueous-phase reactivity of DMAs(V) which could not be explained on the basis of current knowledge. [ABSTRACT FROM AUTHOR]

VITA-1 and VITB-1 are low- and elevated level CRMs, respectively, which were certified for minerals and vitamin contents by National Research Council Canada. The proportions of key ingredients are the same in each formula, and they were prepared in such a way that VITB-1 has twice the amount of minerals and vitamins as VITA-1. The availability of these two matrix-matched CRMs, with different concentrations for all analytes, will not only assist in the validation of procedures and the development of methods for the determination of respective analytes in multivitamins or samples of a similar matrices, but also will be useful for calibration purposes (for the values that are certified). Tablets were individually packaged in trilaminate foil pouches and values presented in the certificate of analysis are expressed on a "as is" basis, with no need for the determination of moisture content on a separate test portion. In addition, certified/reference values are provided per single tablet (mass fraction expressed as both mg/kg and µg/tablet), eliminating the need of a homogenization step prior to analysis. Homogeneity and stability were assessed and included in the final expanded uncertainties of the certified values. Quantity value assignment for both VITA-1 and VITB-1 was based on the use of at least two independent methods, using data generated at NRC and data from external collaborators for confirmation purposes. As a result of this campaign, value assignment was possible for a total of 39 analytes: 24 trace elements and 15 vitamins. [ABSTRACT FROM AUTHOR]

The degree of knowledge of the mechanisms operating in chemical vapor generation (CVG) by aqueous boranes (MBH4, R3N·BH3, M = Na, K and R = H, alkyl) for trace element determination by atomic or mass spectrometry, have been reviewed in the light of the most recent evidence. The attention has been mainly focused on the role played by sample composition – acidity, type of acid or buffer and chemical additives – in the control of the mechanism of CVG of volatile hydrides (Ge, Sn, Pb, As, Sb, Bi, Se, Te, Hg and Cd) under analytical conditions (analyte < 10−6 mol L−1, borane ≥ 10−2 mol L−1) in the absence of interfering species. The available evidence is reported in order to discuss the role played in CVG by some key chemical species, among them the hydrolysis products of borane reagents. Particular emphasis was given to those mechanistic aspects of the chemistry of aqueous boranes that have been clarified thanks to the contribution of CVG coupled with atomic or mass spectrometry, to those that are still controversial and that could stimulate further studies to understand the reactivity of aqueous boranes also for their applications other than CVG. [ABSTRACT FROM AUTHOR]

Chemical vapor generation of cadmium (CVG) by aqueous NaBH4 was investigated with the aim to individuate the mechanisms controlling the generation of volatile cadmium species in the absence of any additive. A continuous flow reactor was employed in combination with atomic absorption spectrometry. An electro-thermal quartz tube atomizer (293–1200 K) and a miniature argon–hydrogen diffusion flame were employed as the atomizers. The reactor system can be used with various chemifold setups which allow different mixing strategies of the sample (2.5–50 μg L−1 of CdII in 0.25 mol L−1 HCl) and reductant (1–3% m/v NaBH4 in 0.1–1.2 mol L−1 NaOH) solutions. The molar ratios of the reagents HCl, NaBH4 and NaOH play a decisive role in determining both the nature of CdII substrates and the hydrolysis products of BH4−, which strongly affected the generation efficiency of volatile Cd species. For the first time the interference effect of dissolved oxygen and the use of BH3OH− in CVG of Cd have been demonstrated. The interference of dissolved oxygen, causing liquid phase interference during the derivatization step, can be removed by degassing the solution with argon. The on-line generation of BH3OH− in a quenched flow reactor indicates that it is more efficient than that of BH4− and it might play a role in CVG of Cd. The combination of BH3OH− derivatization and degassed solutions allows obtaining about 20 and 5 fold increase of sensitivity using a quartz tube and miniature flame, respectively. Volatile cadmium vapors are composed of both atomic and molecular species, and the oxygen removal and/or the use of BH3OH− favors the formation of atoms with respect to molecular species. [ABSTRACT FROM AUTHOR]

Response to multiple microenvironmental cues and resilience to mechanical stress are essential features of trafficking leukocytes. Here, we describe unexpected role of titin (TTN), the largest protein encoded by the human genome, in the regulation of mechanisms of lymphocyte trafficking. Human T and B lymphocytes express five TTN isoforms, exhibiting cell-specific expression, distinct localization to plasma membrane microdomains, and different distribution to cytosolic versus nuclear compartments. In T lymphocytes, the LTTN1 isoform governs the morphogenesis of plasma membrane microvilli independently of ERM protein phosphorylation status, thus allowing selectin-mediated capturing and rolling adhesions. Likewise, LTTN1 controls chemokine-triggered integrin activation. Accordingly, LTTN1 mediates rho and rap small GTPases activation, but not actin polymerization. In contrast, chemotaxis is facilitated by LTTN1 degradation. Finally, LTTN1 controls resilience to passive cell deformation and ensures T lymphocyte survival in the blood stream. LTTN1 is, thus, a critical and versatile housekeeping regulator of T lymphocyte trafficking. [Display omitted] • Human T and B lymphocytes express five isoforms of the giant protein TTN • In T lymphocytes, the LTTN1 isoform regulates the structure of microvilli • LTTN1 regulates integrin activation and chemotaxis • LTTN1 controls cell stiffness and deformability and ensures survival in the circulation Toffali et al. find that human lymphocytes express five isoforms of TTN. In T lymphocytes, the LTTN1 isoform regulates microvilli structure, integrin activation, and chemotaxis. Moreover, LTTN1 controls cell stiffness and resilience to deformation and ensures survival in the blood stream. LTTN1 is, thus, a central regulator of lymphocyte trafficking. [ABSTRACT FROM AUTHOR]

The interaction of chemicals with DNA may lead to genotoxicity, mutation or carcinogenicity. A simple open tubular capillary electrochromatographic method is proposed to rapidly assess the interaction affinity of three environmental contaminants (1,4-phenylenediamine, pyridine and 2,4-diaminotoluene) to DNA by measuring their retention in the capillaries coated with DNA probes. DNA oligonucleotide probes were immobilized on the inner wall of a fused silica capillary that was first derivatized with 3-(aminopropyl)-triethoxysilane (APTES). The difference in retention times and factors was considered as the difference in interaction affinity of the contaminants to the DNA probes. The interaction of the contaminants with both double-stranded (dsDNA) and single-stranded DNA (ssDNA) coatings was compared. Retention factors of 1,4-phenylenediamine, pyridine and 2,4-diaminotoluene in the capillary coated with ssDNA probe were 0.29, 0.42, and 0.44, respectively. A similar trend was observed in the capillary coated with dsDNA, indicating that 2,4-diaminotoluene has the highest affinity among the three contaminants. The relative standard deviation (RSD) for the retention factors was in the range of 0.05–0.69% (n = 3). The results demonstrated that the developed technique could be applied for preliminary screening purpose to provide DNA interaction affinity information of various environmental contaminants. [ABSTRACT FROM AUTHOR]

In analytical chemistry, improvement in instrument performances is always important for achieving better analytical results and obtaining more information on the target analytes. Gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS), which combines powerful separation ability and high sensitivity, has found broad applications in sensitive speciation of organometals such as methylmercury (MeHg), butyltin (BuSn), and seleniomethionine (SeMet). Unfortunately, GC-ICPMS is unable to provide molecular information of the analytes such as molecular fragmentations or isotopic patterns, which are very important for identifying target analytes. A method is reported for the simultaneous determination of organometals including MeHg, dibutyltin (DBT), tributyltin (TBT) and SeMet using a unique interface with gas chromatography-electron ionization mass spectrometry (GC-EIMS) and GC-ICPMS systems synchronously. The method was validated with measurements of MeHg, DBT, TBT and SeMet in the certified reference materials (CRMs) including dogfish liver (DOLT-4), marine sediments (PACS-2) and selenium-enriched yeast (SELM-1). Compared with EIMS, ICPMS achieved a remarkable gain in sensitivity for MeHg, DBT and SeMet (19-, 130- and 2850-fold S/N gain, respectively). The concentrations of MeHg (1.335 ± 0.033 µg g-1), DBT (1.171 ± 0.005 µg g-1) and TBT (0.834 ± 0.003 mg g-1) obtained with isotope dilution are in agreement with the certified values of the corresponding CRMs. With the proposed method, the ICPMS system can provide higher precision and sensitivity, and the EIMS system can provide information on the molecular structure, which is essential for identification of target analytes. [ABSTRACT FROM AUTHOR]

The binding of chlorosulphonated paraffins to collagen triple helices is studied by means of classical molecular dynamics simulations and experimental spectroscopic techniques in order to disclose the principal characteristics of their interaction during the leather fattening process. Indeed, collagen is the main target to develop new leather modifying agents with specific characteristics, and an accurate design of the collagen binders, supported by predictive computational strategies, could be a successful tool to obtain new effective eco-compatible compounds able to impart to the leather the required functionalities and distinctive mechanical properties. Possible effects caused by the tanning agents on the collagen matrix have been identified from both experimental and theoretical points of view. Computational data in agreement with experiment have revealed that chlorosulphonated paraffins can interact favorably with the collagen residues having amine groups in their side chains (Arg, Lys, Asn and Gln) and reduce the tendency of the solvated collagen matrix to swell. However, the interference of chlorosulphonated paraffins with the unfolding process, which is operated mainly by the action of water, can be due both to covalent cross-linking of the collagen chains and intermolecular hydrogen bonding interactions involving also the hydroxyl groups of Hyp, Ser and Thr residues. [ABSTRACT FROM AUTHOR]

The formation of volatile products during the reaction of As( iii), As( v), MeAsO(OH), and MeAsO(OH) with aqueous NaBH has been investigated, and the formation of arsanes, diarsanes, and triarsanes has been detected. The presence of triarsanes is reported here for the first time. Diarsanes and triarsanes are likely formed in condensation cascade reactions, whereas trimethylarsane arises via the transfer of a methyl group. The formation of volatile by-products is considerably reduced by increasing the acidity of the medium and the concentration of NaBH or by the addition of thiols, such as cysteine. A reaction scheme is proposed which reconciles the evidence reported herein and elsewhere in the literature that is valid for both analytical (trace analysis) and non-analytical reaction conditions. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Atherosclerosis has received wide attention as a primary cause of premature death in developed countries. The retention of low-density lipoprotein (LDL) particles in the intima, the inner layer of the capillaries, has been imputed as the main cause of the development of atherosclerotic plaques. The entrapment of LDL is mainly due to the specific interaction between the lysine-rich site on apolipoprotein B-100 (apoB-100), a major apolipoprotein of LDL, and extracellular matrix (ECM) components such as collagen, proteoglycans, and glycosaminoglycans (GAGs). Although valuable techniques already exist for studies on apoB-100 and ECM interactions, there is continued need for miniaturized tools that can complement the tools already available and even provide totally new data. This work explores the applicability of the quartz crystal microbalance (QCM) for interaction studies between apoB-100 peptide fragments and various components of the ECM. Two positive peptide fragments, PP and PP2, and two components of the ECM, collagen I and a selected GAG, chondroitin 6-sulfate (C6S), were immobilized on polystyrene and carboxyl sensor chips. C6S was injected as analyte for PP- and PP2-coated surfaces, while PP was the analyte for collagen I and C6S surfaces. The estimated dissociation constant ( KD) indicates that the interactions occur via the positive residues, lysine and arginine, of apoB-100. The continuous-flow QCM system employed in this study is shown to be an excellent tool for the elucidation of interactions between these types of biomolecules. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Electrochromatography with open tubular capillaries coated with human low density lipoprotein (LDL) particles and their protein-free derivatives was studied as a method for their in situ enzymatic modification. LDL particles as monolayers or their protein-free derivatives (lipid microemulsions) were coated on 50 μm i.d. capillaries, which resemble tiny human blood vessels in size, the arterioles. The immobilized LDL particles were exposed to sphingomyelinase, phospholipase A2 or α-chymotrypsin at 25 and 37 °C. The mobility of the electro-osmotic flow was employed as a surface charge indicator, and the retention factors of steroids were used as hydrophobicity indicators. Moreover, the capillaries were, for the first time, coated with lipid microemulsions containing either LDL-derived or commercial lipids, and the immobilized microemulsions were treated with sphingomyelinase in capillary. The results demonstrate that open tubular capillaries provide a good microreactor for the in situ modification of LDL particles and lipid microemulsions. The technique only requires extremely low quantities of LDL particles, lipid microemulsions, and enzymes. It allows quick and easy alteration of the reaction conditions, and the enzymes can be collected and reused. Asymmetrical flow field flow fractionation provides useful information on the size of the enzymatically modified LDL particles. [ABSTRACT FROM AUTHOR]

The effect of mM concentrations of K3[Fe(CN)6], Fe(III), Mo(VI), KSCN and KMnO4 on the generation of BiH3 by the reaction of 0.2–10 μg ml−1 Bi(III) with 0.2 M tetrahydroborate(III) at 1 M acidity (HCl or HNO3) was investigated. Chemical vapour generation (CVG) of BiH3 was investigated by atomic absorption spectrometry using a continuous flow reaction system (CF–CVG–AAS) and different mixing sequences and reagent reaction times. Gas chromatography–mass spectrometry (GC–MS) was employed in batch generation experiments with NaBD4. In the absence of additives, the formation of Bi0 at high concentrations of Bi(III) caused rollover of calibration curves and limited the linear range to less than 1 μg ml−1 Bi(III). In the presence of additives, the formation of Bi0 was not observed and the linear range was increased to 5 μg ml−1 of Bi(III) while rollover was completely removed. GC–MS experiments indicated that the presence of additives did not affect the direct transfer of H from boron to bismuth. Experiments with CF–CVG–AAS and different mixing sequences and reagent reaction times suggest that additives act by preventing the formation of Bi0 through the formation of reaction intermediates which evolve towards the formation of BiH3 at elevated Bi(III)/NaBH4 ratios. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

A rapid, accurate, and precise method is described for the determination of Pb in wine using continuous-flow hydride generation atomic fluorescence spectrometry (CF-HGAFS). Sample pretreatment consists of ten-fold dilution of wine followed by direct plumbane generation in the presence of 0.1 mol L−1 HCl and 1% m/v K3[Fe(CN)6] with 1% m/v NaBH4 as reducing agent. An aqueous standard calibration curve is recommended for Pb quantification in wine sample. The method provides a limit of detection and a limit of quantification of 0.3 μg L−1 and 1 μg L−1, respectively. The relative standard deviation varies between 2–6% (within-run) and 4–11% (between-run) at 3–30 μg L−1 Pb levels in wine. Good agreement has been demonstrated between results obtained by CF-HGAFS and direct electrothermal atomic absorption spectrometry in analyses of red and white wines within the concentration range of 9.2–25.8 μg L−1 Pb. [ABSTRACT FROM AUTHOR]

Hydrophobic-interaction chromatography coupled on-line with chemical-vapor-generation atomic-fluorescence spectrometry (HIC-CVGAFS), optimized recently for the analysis of thiol-containing proteins under denaturing conditions, has been used to study the chemical reduction of denatured proteins. Four proteins chosen as models (human serum albumin (HSA), bovine serum albumin (BSA),a-lactalbumin (a-Lac) from bovine milk, and lysozyme from chicken egg (Lys)) were denatured with urea and reduced with dithiothreitol (DTT), with selenol as catalyst. The method is based on derivatization of the -SH groups of proteins withp-hydroxymercurybenzoate (PHMB), followed by HIC separation and post-column on-line reaction of the derivatized reduced, denatured proteins with bromine generated in situ. HgII, derived from rapid conversion of uncomplexed and protein-complexed PHMB, is selectively detected by AFS in an Ar/H2 miniaturized flame after sodium borohydride (NaBH4) reduction to Hg°. The yield of the reduction was studied as a function of reductant concentration, reduction time (tred), and urea concentration. Results showed that the optimum values for DTT and selenol concentrations and fortred were between 1 and 100 mmol L-1 and between 1 and 20 min, respectively, depending on the protein studied. The percentage disulfide bond reduction increases as the urea concentration used for protein denaturation increases, giving a single-step sigmoid increment for single-domain, low-MW proteins (a-Lac and Lys), and a two-step sigmoid increment for multi-domain, high MW proteins (HSA and BSA). The shapes of plots of percentage reduced disulfide against urea concentration are characteristic of each protein and are correlated with the location of S-S in the protein. Under the adopted conditions complete protein denaturation is the conditio sine qua non for obtaining 100% S-S reduction. The detection limit for denatured, reduced proteins examined under the optimized conditions was found to be in the range 1-5×10-12 mol L-1 (10-30 pg), depending on the protein considered. [ABSTRACT FROM AUTHOR]

The article presents a call for solutions to an analytical chemistry challenge about vitamin B3.

The article discusses the preparation of pink tea which known as Noon chai with special tea leaves such as Kashmiri chai, water, salt, baking soda and milk. It states that the tea leaves are boiled for a long time for the extraction of polyphenols with the addition of baking soda and milk to achieve the pink color of the tea. It also cites the phenolic content and antioxidative capacity of the tea.

The article presents the journal's challenge involving Pink tea or Noon Chai which is a Kashmiri beverage.

Correction for 'The contribution of chemical vapor generation coupled with atomic or mass spectrometry to the comprehension of the chemistry of aqueous boranes' by Alessandro D'Ulivo et al., J. Anal. At. Spectrom., 2019, 34, 823–847. [ABSTRACT FROM AUTHOR]

The article discusses the answers to the mystery challenge on the deficiency of niacin or vitamin B3 in corn-based diet that has led to an epidemic of pellagra in Europe and the U.S. The alkaline treatment process for corn known as nixtamalization, originating from the Mesoamerica region, is also discussed. According to the author the Europeans disregarded the process of nixtamalization which has led to spread of Pellagra.

The article offers details of the absinthe challenge, which is a herbal spirit made from the botanicals wormwood, anise and fennel.

The article focuses on the semi-metal hydride generation mechanism that invoke the formation of nascent hydrogen. According to nascent hydrogen theory, nascent hydrogen is formed during acid decomposition of borohydride, and it is responsible for the derivation of the element to the hydride, which can be validated by the use of deuterium-labeled reagents. A brief history of arsenic used as poison and its discovery through tests are provided.

The article focuses on the accusations that absinthe, causes absinthism syndrome during the 20th century. Topics discussed include thujone content of the absinthe which was overestimated because of the crude analytical techniques during the period, essential oils contained by absinthe which can dissolve several compounds, including monoterpene thujone and the aromatic compound anethol, and dilution of absinthe with cold water which led to stability of microemulsion.