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A multicolor flow cytometry panel was designed and optimized to define the following nine mouse T cell subsets: Treg (CD3+ CD4+ CD8- FoxP3+ ), CD4+ T naive (CD3+ CD4+ CD8- FoxP3- CD44int/low CD62L+ ), CD4+ T central memory (CD3+ CD4+ CD8- FoxP3- CD44high CD62L+ ), CD4+ T effector memory (CD3+ CD4+ CD8- FoxP3- CD44high CD62L- ), CD4+ T EMRA (CD3+ CD4+ CD8- FoxP3- CD44int/low CD62L- ), CD8+ T naive (CD3+ CD8+ CD4- CD44int/low CD62L+ ), CD8+ T central memory (CD3+ CD8+ CD4- CD44high CD62L+ ), CD8+ T effector memory (CD3+ CD8+ CD4- CD44high CD62L- ), and CD8+ T EMRA (CD3+ CD8+ CD4- CD44int/low CD62L- ). In each T cell subset, a dual staining for Ki-67 expression and DNA content was employed to distinguish the following cell cycle phases: G0 (Ki67- , with 2n DNA), G1 (Ki67+ , with 2n DNA), and S-G2 /M (Ki67+ , with 2n

BACKGROUND Fresh-cut vegetables are subjected to multiple stressing agents including: (i) slicing, which induces cellular decompartmentalization; (ii) low refrigeration temperatures, responsible for chilling injury in the most sensitive products (e.g. tomatoes), and (iii) storage time because tissue senescence and aging can occur and reduce the shelf-life. In tomato slices, one of the most important issues is the membrane, which is responsible for several disorders related to the alteration of physiological processes, including ethylene biosynthesis. RESULTS Electrolyte leakage and the content of thiobarbituric acid reactive substances in sliced tomatoes increased over time at two storage temperatures (4 °C and 15 °C) compared with intact fruit for the commercial variety (cultivar) Jama used as reference. However, in the tomato Italian landrace Canestrino, electrolyte leakage in sliced fruits increased after 120 h of storage compared to intact tomatoes, while the thiobarbituric acid reactive substance content increased rapidly over time at both storage temperatures. In the packages, higher ethylene content and carbon dioxide concentrations were detected in sliced tomatoes compared with intact fruits for both genotypes. In the most sensitive genotype for slicing (Jama), phospholipase C activity increased in tomato slices after 24 h of storage, but phospholipase D reached a higher value only at 168 h after processing at 4 °C of storage. CONCLUSIONS The results evidence that the main damage in slices of full ripe tomatoes is more related to cutting, rather than chilling injury due to storage temperatures, with differences related to the genotype. Slicing enhanced membrane catabolism, ethylene production, and enzyme activity of phospholipases with a significant genotype effect. © 2021 Society of Chemical Industry.

The cell cycle of antigen-specific T cells in vivo has been examined by using a few methods, all of which possess some limitations. Bromodeoxyuridine (BrdU) marks cells that are in or recently completed S-phase, and carboxyfluorescein succinimidyl ester (CFSE) detects daughter cells after division. However, these dyes do not allow identification of the cell cycle phase at the time of analysis. An alternative approach is to exploit Ki67, a marker that is highly expressed by cells in all phases of the cell cycle except the quiescent phase G0. Unfortunately, Ki67 does not allow further differentiation as it does not separate cells in S-phase that are committed to mitosis from those in G1 that can remain in this phase, proceed into cycling, or move into G0. Here, we describe a flow cytometric method for capturing a "snapshot" of T cells in different cell cycle phases in mouse secondary lymphoid organs. The method combines Ki67 and DNA staining with major histocompatibility complex (MHC)-peptide-multimer staining and an innovative gating strategy, allowing us to successfully differentiate between antigen-specific CD8 T cells in G0, in G1 and in S-G2/M phases of the cell cycle in the spleen and draining lymph nodes of mice after vaccination with viral vectors carrying the model antigen gag of human immunodeficiency virus (HIV)-1. Critical steps of the method were the choice of the DNA dye and the gating strategy to increase the assay sensitivity and to include highly activated/proliferating antigenspecific T cells that would have been missed by current criteria of analysis. The DNA dye, Hoechst 33342, enabled us to obtain a high-quality discrimination of the G0/ G1 and G2/M DNA peaks, while preserving membrane and intracellular staining. The method has great potential to increase knowledge about T cell response in vivo and to improve immuno-monitoring analysis.

Drug-induced liver injury (DILI) is a challenging clinical event in medicine, particularly because of its ability to present with a variety of phenotypes including that of autoimmune hepatitis or other immune mediated liver injuries. Limited diagnostic and therapeutic tools are available, mostly because its pathogenesis has remained poorly understood for decades. The recent scientific and technological advancements in genomics and immunology are paving the way for a better understanding of the molecular aspects of DILI. This review provides an updated overview of the genetic predisposition and immunological mechanisms behind the pathogenesis of DILI and presents the state-of-the-art experimental models to study DILI at the pre-clinical level.

In the present paper we describe the optimization and the application of a chromatographic method suitable to get all four diastereoisomers of C24–C25 cyclopropyl dafachronic acid derivatives in sufficient amount for their biological appraisal towards the nuclear hormone receptor transcription factor DAF-12. A preliminary column screening of six anion exchange type Cinchona alkaloid-based chiral stationary phases (CSPs) allowed to identify the one with a quinine scaffold and carrying a O-9-(3,5-bis(trifluoromethyl)phenyl) moiety at C9 position as the best CSP. Few modifications of the experimental conditions revealed that a content of 18 mM acetic acid used as counterion and displacer in acetonitrile and a column temperature fixed at 35 °C were optimal for the simultaneous discrimination of all four diastereoisomers with a 1.0 mL/min flow rate. With such conditions, transoid (S,S) and (R,R) diastereoisomers were resolved with RS > 1.4. With non chiral reversed-phase columns, neither the cisoid nor the transoid diastereoisomers could be resolved. This way, ca. 1.0 mg of each stereoisomer was isolated with a diastereomeric purity >98%, suitable for the following biological tests. The indirect stereochemical assignments of the four diastereoisomers, and hence the corresponding chromatographic elution order (24R,25R)

In the present study, the "Inverted Chirality Columns Approach (ICCA)" was applied to follow an asymmetric synthetic reaction, namely, the addition of butan-2-one to trans-β-nitrostyrene, catalysed by (S)-proline, leading to the formation of 3-methyl-4-phenyl-5-nitro-2-pentan-2-one. The ICCA method was applied to overcome the lack of pure enantiomeric standards. The two widely employed (R,R)- and (S,S)-Whelk-O1 chiral stationary phases (CSPs), incorporating fully synthesized enantiomeric chiral selectors, were profitably used for this purpose. The enantioselective analysis with the two CSPs was performed under optimized reversed-phase conditions with a water/acetonitrile (60/40, v/v) eluent. In the probe reaction under investigation, a diastereomeric excess90% was found according to a well-established reaction mechanism, thus affording the enantiomer couple (3S,4R)-3-methyl-4-phenyl-5-nitropentan-2-one and (3R,4S)-3-methyl-4-phenyl-5-nitropentan-2-one as the main product. Therefore, the attention was exclusively focused on this enantiomers pair. Rather similar retention and separation factor [1.12 with (R,R)-Whelk-O1 and 1.13 with (S,S)-Whelk-O1] values as well as resolutions [2.06 with (R,R)-Whelk-O1 and 2.30 with (S,S)-Whelk-O1] were produced by the two enantiomeric CSPs. Applying the ICCA concept allowed to identify the two enantiomers-related peaks in the chromatograms, ultimately indicating a 65-to-35 enantiomeric per cent ratio. Electronic circular dichroism (ECD) and high-resolution mass spectrometry analyses of the two peaks collected during the enantioselective analyses further confirmed the enantiomeric nature of the identified compounds. The (3S,4R) (3R,4S) enantiomer elution order with the (R,R)-Whelk-O1 was fully disclosed thanks to ECD studies coupled with in silico quantum mechanical simulations. As expected, reversed elution order turned out with (S,S)-Whelk-O1.

The aim of this preliminary study is to understand and simulate the hydric behaviour of a porous material in the presence of protective treatments. In particular, here the limestone Lumaquela deAjarte is considered before and after the application of the silane-based product ANC. A recently developed mathematical model was applied in order to describe the capillary rise of water in stone specimens. The model was calibrated by using experimental data concerning the water absorption by capillarity in both treated and untreated stone specimens. With a suitable calibration of the main parameters of the model and of the boundary conditions, it was possible to reproduce the main features of the experimentally observed phenomenon.

Owing to their pronounced polarity, hydrophilic interaction liquid chromatography (HILIC) can be considered as the elective choice for the LC analysis of aminoglycoside (AG) antibiotics. In the present work, a gradient program was optimized for the first time with a diol-type stationary phase and an evaporative light scattering detector (ELSD), thus allowing the almost complete separation of the nine analysed AGs: spectinomycin, dihydrostreptomycin, streptomycin A, gentamicin C1, amikacin, kanamycin A, paromomycin, apramycin and neomycin. In the optimized analysis conditions, analyte retention was found to be governed by a multimodal mechanism encompassing electrostatic, partitioning and hydrophilic interactions. However, the gradient mode of elution complicated a deep understanding of the influence of each contribution on the retention behaviour. The developed HILIC-ELSD method was applied for the analysis of commercial tablets containing neomycin co-formulated with the polypeptide antibiotic bacitracin. The method was fully validated according to the guidelines enshrined in the International Conference on Harmonization (ICH). The use of the diol-type stationary phase was well suited for implementing a successful 2D-HPLC system. Indeed, in order to cope with the absence of chemoselectivity for the couples amikacin/kanamycin and paromomycin/apramycin, a successful 2D-HPLC method was implemented with the "heart-cut" approach and the use of either heptafluorobutyric (for the former) or perfluorooctanoic acid (for the latter) as the ion-pair reagent in the second RP-LC dimension.

Background p130 Crk-associated substrate (p130CAS; also known as BCAR1) is a scaffold protein that modulates many essential cellular processes such as cell adhesion, proliferation, survival, cell migration, and intracellular signaling. p130Cas has been shown to be highly expressed in a variety of human cancers of epithelial origin. However, few data are available regarding the role of p130Cas during normal epithelial development and homeostasis. Methods To this end, we have generated a genetically modified mouse in which p130Cas protein was specifically ablated in the epidermal tissue. Results By using this murine model, we show that p130Cas loss results in increased cell proliferation and reduction of cell adhesion to extracellular matrix. In addition, epidermal deletion of p130Cas protein leads to premature expression of “late” epidermal differentiation markers, altered membrane E-cadherin/catenin proteins localization and aberrant tyrosine phosphorylation of E-cadherin/catenin complexes. Interestingly, these alterations in adhesive properties in absence of p130Cas correlate with abnormalities in progenitor cells balance resulting in the amplification of a more committed cell population. Conclusion Altogether, these results provide evidence that p130Cas is an important regulator of epidermal cell fate and homeostasis.

International audience; We propose a mathematical model to describe enzyme-based tissue degradation in cancer therapies. The proposed model combines the poroelastic theory of mixtures with the transport of enzymes or drugs in the extracellular space. The effect of the matrix degrading enzymes on the tissue composition and its mechanical response are accounted for. Numerical simulations in 1D, 2D and ax-isymmetric (3D) configurations show how an injection of matrix degrading enzymes alters the porosity of a biological tissue. We eventually exhibit numerically the main consequences of a matrix degrading enzyme pretreatment in the framework of chemotherapy: the removal of the diffusive hindrance to the penetration of therapeutic molecules in tumors and the reduction of interstitial fluid pressure which improves transcapillary transport. Both effects are consistent with previous biological observations.

Sliced tomatoes soften rapidly as well as becoming translucent. To develop a physiologically-based mechanism to describe softening the firmness of two cultivars, as a function of time, storage temperature, type of compression (repeated on the same spot or single measurements on consecutive spots on the equator of the pericarp) and initial maturity was measured using tomato slices. The proposed mechanism assumes that the softening of slices is radically different from that of whole tomatoes and depends on the stage of ripening at slicing. The mechanism is also based on the assumption that the pericarp solubility will quickly increase because of exposure to, amongst others, vacuolar contents with a low pH. This exposure will have a more serious effect on the firmness behaviour of ripe tomatoes because the pericarp tissue will have been exposed longer to a lower pH environment that will affect pectin solubility. A kinetic model that describes the individual firmness behaviour over time was developed. This model described trends well despite the high variability of the raw data. It was found that firmness loss induced by wounding occurs within 12 h. The effect of the initial maturity on the final firmness of the slices was large. The model indicates that consumer acceptance of sliced tomatoes is greatly affected by selection of cultivars with sufficient final (structural) firmness combined with a thorough assessment of the maturity at the time of slice preparation.

This paper shows the first study results of the mechanical characterization of a commercial polypropylene (PP) polymer. Before testing, a mold for injection molding process has been designed and realized. Three different specimens can be produced, for three different tests: tensile, Charpy and Hopkinson bar. In-cavity pressure and temperature sensors are installed next to the molded item to have direct information about process phases. After the description of the instrumentation, the correlation between injection molding input parameters and mechanical behavior of the material has been assessed. In particular, tensile tests have been carried out to investigate the influence of: melt temperature, mold temperature, packing pressure and cooling time. A Design of Experiment plan has been set up to establish the tests to be performed. Results show the influence of mold temperature and holding pressure on mechanical strength of the polymer.

In search for new enantioselectivity profiles, the N-decyl-S-trityl-(R)-cysteine [C10-(R)-STC] was synthesized through a one-step procedure and then hydrophobically adsorbed onto an octadecylsilica surface to generate a stable chiral stationary phase for ligand-exchange chromatography (CLEC-CSP) applications. The CLEC analysis was carried out on underivatized amino acids, by using a Cu(II) sulphate (1.0 mM) containing aqueous eluent system. Most of the analysed compounds (34 out of 45) were enantiodiscriminated by the C10-(R)-STC-based CSP, with resolution factor (RS) values up to 8.86. Conformationally rigid and hydrophobic ligands often experienced the largest enantioselectivity effects. A high loadability emerged from the analysis of rac-NorVal (selected as prototype test compound): up to 20 mg/mL were efficiently enantioseparated with the CLEC-CSP. Two in-line hand-made cartridges filled with a strong cation-exchange resin allowed the effective catching of Cu(II) ions after the semi-preparative enantioseparation. The quantitative recovery of the rac-NorVal enantiomers was made possible by flowing through the cartridge a 5% (v) ammonia solution. The CLEC phase proved successful in the enantioselective analysis of a commercially available (S)-Leu containing tablet. Furthermore, in order to understand the molecular basis for a successful use of the C10-(R)-STC-based CLEC system, a descriptive structure-separation relationship study was performed. As a result, all compounds with a MEAN-QPlogS (a hydrophilicity descriptor) value lower than 0.373 can be most likely enantioseparated with the CLEC system under investigation. In the work, the numerous aspects complying with the principles of green chromatography are highlighted and discussed.

A Special Year of Italian Medchem: Guest Editors Violetta Cecchetti and Benedetto Natalini of the University of Perugia look back at the XXIV National Meeting in Medicinal Chemistry (NMMC 2016) held in Perugia, Italy. It was this at special conference where ChemMedChem also held its 10th Anniversary Celebration. In this editorial, they provide highlights of last year's events, including some key presentations now collected in this Special Issue.

In response to the outburst of research in the field of synthetic medicinal chemistry, enantioselective chromatography methods based on the use of chiral stationary phases (CSPs) found immediate acceptance as the elective choice for the analytical determinations of the enantiomeric purity of synthetic compounds. In contrast to an initial scepticism, also the preparative-scale applications are gaining increasing recognition as a powerful alternative to enantioselective synthesis for the supply of pure enantiomers of bioactive compounds. The increasing success of liquid chromatography methods has been made possible thanks to the development of highly efficient CSPs allowing the enantioresolution of practically all the chemical classes of chiral compounds. However, only few CSPs are really suitable for preparative- scale applications, being the loading capacity is the major concern for preparativescale enantioseparations. The cellulose- and amylose-based CSPs present the highest loading capacity and enantiodiscrimination power, which makes these CSPs the most versatile and applicable for preparative-scale applications in all the applicable elution modes (reversedphase, normal-phase, and with polar-organic or polar-ionic eluents). However, also other types of CSPs have been successfully employed at this regard (brush-type phases, polyacrylamide and cross-linked di-allyltartardiamide phases as well as cyclodextrin, and glycopeptide containing phases). Several instrumental methods exist for the determination of the absolute configuration of organic compounds in absence of known enantiopure reference standards. The most widely known are X-ray crystallography, followed by chirooptical methods [e.g., electronic and vibrational circular dichroism (ECD and VCD, respectively)] and nuclear magnetic resonance (NMR) spectroscopy. All these aspects will be treated in the review.

For years, d -amino acids were thought to have a minor function in biological processes compared to that of l- enantiomers. Recently, many studies have shown that d- amino acids are present in high concentrations in microorganisms, plants, mammals and humans and execute specific biological functions. One relevant example is that of d- cysteine, whose hydrogen sulfide-producing properties have been found to protect neurons against oxidative stress and to promote dendritic development. Herein, we introduce a chiral LC MS method for the rapid determination of cysteine enantiomers under polar ionic elution conditions (MeOH/MeCN/H2O 49/49/2 v/v/v, containing 50 mM formic acid and 50 mM ammonium formate) developed on a Chiralpak® ZWIX(+) chiral stationary phase. Cysteine enantiomers were analysed in biological samples after efficient reduction of the disulfide bond in cystine; the latter was achieved with the use of 1,4-dithio- dl- threitol as a reducing agent. A baseline resolution (RS = 2.7) was obtained, and the d- enantiomer eluted before the l- enantiomer. For the enantioselective analysis, cysteine was labelled with AccQ-Tag reagent, resulting in improved chromatographic behaviour and MS detection sensitivity. The method was validated according to the Food and Drug Administration guidelines. Good linearity was determined in the ranges of 0.05-0.50 mg/L for d- cysteine and 0.11-0.56 mg/L for l- cysteine. The repeatability and intermediate precision were found to be lower than 4.0%, with trueness ranging from 95.6 to 100.2% for both enantiomers. The LOD and LOQ values were 0.02 and 0.05 mg/L for d- cysteine and 0.04 and 0.11 mg/L for l- cysteine, respectively. The method was successfully applied to cell culture samples treated with d- cysteine.

International audience; Background and Objective: The paper focuses on the numerical strategies to optimize a plasmid DNA delivery protocol, which combines hyaluronidase and electroporation. Methods: A well-defined continuum mechanics model of muscle porosity and advanced numerical optimization strategies have been used, to propose a substantial improvement of a pre-existing experimental protocol of DNA transfer in mice. Our work suggests that a computational model might help in the definition of innovative therapeutic procedures, thanks to the fine tuning of all the involved experimental steps. This approach is particularly interesting in optimizing complex and costly protocols, to make in vivo DNA therapeutic protocols more effective. Results: Our preliminary work suggests that computational model might help in the definition of innovative therapeutic protocol, thanks to the fine tuning of all the involved operations. Conclusions: This approach is particularly interesting in optimizing complex and costly protocols for which the number of degrees of freedom prevents a experimental test of the possible configuration.

Background High-flow oxygen therapy via nasal cannula (HFOTNASAL) increases airway pressure, ameliorates oxygenation and reduces work of breathing. High-flow oxygen can be delivered through tracheostomy (HFOTTRACHEAL), but its physiological effects have not been systematically described. We conducted a cross-over study to elucidate the effects of increasing flow rates of HFOTTRACHEAL on gas exchange, respiratory rate and endotracheal pressure and to compare lower airway pressure produced by HFOTNASAL and HFOTTRACHEAL. Methods Twenty-six tracheostomized patients underwent standard oxygen therapy through a conventional heat and moisture exchanger, and then HFOTTRACHEAL through a heated humidifier, with gas flow set at 10, 30 and 50 L/min. Each step lasted 30 min; gas flow sequence during HFOTTRACHEAL was randomized. In five patients, measurements were repeated during HFOTTRACHEAL before tracheostomy decannulation and immediately after during HFOTNASAL. In each step, arterial blood gases, respiratory rate, and tracheal pressure were measured. Results During HFOTTRACHEAL, PaO2/FiO2 ratio and tracheal expiratory pressure slightly increased proportionally to gas flow. The mean [95% confidence interval] expiratory pressure raise induced by 10-L/min increase in flow was 0.2 [0.1–0.2] cmH2O (ρ = 0.77, p TRACHEAL limited the negative inspiratory swing in tracheal pressure; at 50 L/min, but not with other settings, HFOTTRACHEAL increased mean tracheal expiratory pressure by (mean difference [95% CI]) 0.4 [0.3–0.6] cmH2O, peak tracheal expiratory pressure by 0.4 [0.2–0.6] cmH2O, improved PaO2/FiO2 ratio by 40 [8–71] mmHg, and reduced respiratory rate by 1.9 [0.3–3.6] breaths/min without PaCO2 changes. As compared to HFOTTRACHEAL, HFOTNASAL produced higher tracheal mean and peak expiratory pressure (at 50 L/min, mean difference [95% CI]: 3 [1–5] cmH2O and 4 [1–7] cmH2O, respectively). Conclusions As compared to standard oxygen, 50 L/min of HFOTTRACHEAL are needed to improve oxygenation, reduce respiratory rate and provide small degree of positive airway expiratory pressure, which, however, is significantly lower than the one produced by HFOTNASAL.

Albendazole is a first line drug for the treatment of several parasitic diseases in humans. Some parasites target the lungs, however lung delivery of albendazole has so far not been reported. We have developed albendazole-based powders suitable for pulmonary delivery, and studied the impact of surfactant on the formulation properties. High-pressure homogenization followed by spray drying was used to produce inhalable particles of albendazole containing the bile salts sodium taurocholate and sodium glycocholate. The process resulted in porous microparticles, that exhibited good spray drying yield (>50%), low moisture contents ( 71%) or conditions that simulate decreased respiratory capacity (respiratory fraction > 49%). The powders did not disturb lung surfactant function. The comparison between both formulations has revealed that the properties of the surfactants affect mainly the particle size of the suspensions and the porosity of the powders. The higher porosity of the albendazole-sodium taurocholate powder led to an enhanced aerodynamic performance of the formulation compared to albendazole-sodium glycocholate. The developed albendazole powders may pave a way for local lung treatment of parasitic diseases. Fil: Natalini, Paola Marisel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina. University of Southern Denmark; Dinamarca Fil: Razuc, Mariela Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina Fil: Sørli, Jorid Birkelund. The National Research Centre for the Working Environment; Dinamarca Fil: Bucala, Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Química; Argentina Fil: Ramírez Rigo, María Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; Argentina. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia; Argentina

The early diagnosis of mastitis is an essential factor for the prompt detection of the animal for further actions. In fact, if not culled, infected cows must be segregated from the milking herd and milked last, or milked with separate milking units. Besides microbiological analysis, the somatic cell count (SCC) commonly used as predictor of intramammary infection, frequently lead to a misclassification of milk samples. To overcome these limitations, more specific biomarkers are continuously evaluated. The total amino acid content increases significantly in mastitic milk compared to normal milk. S. aureus requires branched-chain amino acids (BCAAs&mdash, isoleucine, leucine, and valine) for protein synthesis, branched-chain fatty acids synthesis, and environmental adaptation by responding to their availability via transcriptional regulators. The increase of BCAAs in composite milk has been postulated to be linked to mammary infection by S. aureus. The aim of this work is to demonstrate, by a direct ion-pairing reversed-phase method, based on the use of the evaporative light-scattering detector (IP-RP-HPLC-ELSD), applied to 65 composite cow milk samples, a correlation between the concentration of isoleucine and leucine, and S. aureus load. The correlation coefficient, r, was found to be 0.102 for SCC (p = 0.096), 0.622 for isoleucine (p &lt, 0.0001), 0.586 for leucine (p &lt, 0.0001), 0.013 for valine (p = 0.381), and 0.07 for tyrosine (p = 0.034), standing for a positive correlation between S. aureus and isoleucine and leucine concentration. The link between the content of BCAAs, isoleucine and leucine, and udder infection by S. aureus demonstrated with our study has an important clinical value for the rapid diagnosis of S. aureus mastitis in cows.

A data-matrix (DM)-technology approach in cell biology is implemented as an efficient method for the multiparameter monitoring of cell cultures. The proposed method takes advantage of the know-how developed for fault tolerance in digital information technology by measuring the amount of errors induced by intervening cells upon checking a DM code placed behind them. It gives continuous access to several quantitative parameters of the observed culture, such as cell coverage, mean size, viability, and transfection efficiency.

Chiral ligand-exchange chromatography is one of the elective strategies for the direct enantioresolution of small chelating compounds: amino acids, diamines, amino alcohols, diols, small peptides, etc. Unlike other methods, the interaction between chiral selector and analyte enantiomers is mediated by a cation, thus producing diastereomeric ternary complexes. Two main approaches are conventionally applied in chiral ligand-exchange chromatography. The first relies upon chiral stationary phases where the chiral selector is either covalently immobilized or physically adsorbed onto suitable packing materials (coated phases). In the second approach, chiral molecules are added to the eluent, thus generating chiral eluent systems. Among the advantages of chiral ligand-exchange chromatography, the generation of UV/vis-active metal complexes, and the use of commercially available or easy-to-synthesize chiral selectors, in combination to rather inexpensive achiral columns for coated phases and chiral eluents, are noteworthy. Besides amino acids and amino alcohols, other species have proven suitable for chiral ligand-exchange chromatography applications. Recently, the use of either chiral ionic liquids or micellar liquid chromatography systems as well as the successful off-column formation of diastereomeric complexes have expanded the selectivity profiles and application fields. All of these issues are touched in the review, shedding light to the contributions appeared in the last decade.

Keladi tikus umumnya diperbanyak secara vegetatif sehingga ragamgenetiknya sempit. Penelitian peningkatan keragaman genetik pada keladitikus melalui kultur in vitro telah dilakukan di Laboratorium KulturJaringan, Balai Penelitian Tanaman Obat dan Aromatik (Balittro) Bogorpada bulan April sampai Desember 2005. Bahan tanaman yang digunakanadalah daun steril keladi tikus in vitro. Media dasar yang digunakan adalahMurashige and Skoog (MS) yang diperkaya vitamin dari group B. Sebagaisumber energi digunakan sukrosa sebanyak 30 g/l. Penelitian terdiri daridua tahap yaitu induksi dan regenerasi kalus. Perlakuan yang diuji padatahap I adalah beberapa taraf konsentrasi auksin (2,4-D) secara tunggalmaupun kombinasi dengan sitokinin (kinetin) terhadap induksi kalus yaitu: 2,4-D 0,1 mg/l; 2,4-D 0,5 mg/l; 2,4-D 1,0 mg/l; 2,4-D 0,1 + kinetin 0,1mg/l; 2,4-D 0,5 mg/l + kinetin 0,1 mg/l; 2,4-D 1.0 mg/l + kinetin 0,1 mg/l;2,4-D 0,1 mg/l + kinetin 0,3 mg/l; 2,4-D 0,5 mg/l +kinetin 0,3 mg/l dan2,4-D 1,0 mg/l + kinetin 0,3 mg/l. Tahap II adalah beberapa tarafkonsentrasi benzyl adenin untuk regenerasi kalus. Penelitian disusunmenggunakan rancangan acak lengkap dengan pola faktorial dan limaulangan, dan setiap ulangan terdiri dari satu eksplan. Faktor pertamaadalah asal kalus dan faktor kedua adalah beberapa taraf konsentrasi BAyaitu : BA 0,1 mg/l ; BA 0,3 mg/l dan BA 0,5 mg/l. Parameter yangdiamati adalah waktu inisiasi kalus, struktur dan warna kalus, jumlahtunas serta penampilan kultur secara visual. Hasil penelitian menunjukkanbahwa kalus asal eksplan daun dapat diinduksi pada perlakuan 2,4-D 1,0mg/l + kinetin 0,1 mg/l dan 2,4-D 1,0 mg/l + kinetin 0,3 mg/l denganwaktu inisiasi 8 sampai 10 minggu setelah perlakuan. Regenerasi kalusterbaik diperoleh pada medium 2,4-D 1,0 mg/l + kinetin 0,3 mg/lmengandung BA 0,3 mg/l dengan rata-rata tunas dan daun yang dihasilkansebanyak 13,2 tunas dan 4,4 daun.Kata kunci : Keladi tikus, Typonium flagelliforme Lodd., induksi,regenerasi kalus, in vitroABSTRACTInduction and regeneration of Rodent tuber calli throughin vitro cultureRodent tuber plant (Typonium flagelliforme Lodd) is commonlypropagated vegetatively, the repro its genetic variation is narrow. Aresearch to increase the genetic variability of the plant was conducted inTissue Culture Laboratory of the Indonesian Medicinal and AromaticResearch Institute, Bogor from April to December 2005. The leaf ofRodent tuber in vitro used as an explants. Murashige and Skoog (MS)medium used as basic medium, supplemented with vitamin from B group,sucrose 30 g/l was added into the medium as carbon source. The researchconsist of two steps : 1) calli induction and 2) calli regeneration. Thetreatment tested in first step : 2.4-D 0.1 mg/l; 2.4-D 0.5 mg/l; 2.4-D 1,0mg/l; 2.4-D 0.1 + kinetin 0.1 mg/l; 2.4-D 0.5 mg/l + kinetin 0.1 mg/l; 2.4-D 1.0 mg/l + kinetin 0,1 mg/l; 2.4-D 0.1 mg/l + kinetin 0.3 mg/l; 2.4-D 0.5mg/l + kinetin 0.3 mg/l and 2.4-D 1.0 mg/l + kinetin 0.3 mg/l. In thesecond steps, several concentration of BA were tested i.e: BA 0,1 mg/l ;BA 0,3 mg/l and BA 0,5 mg/l. The experiment was arranged incompletely randomized design with factorial pattern. Each treatmentconsist of five replications. The parameters observed were time of calliinitiation, texture, colour of calli and number of shoot and leaves inregeneration. The result showed that calli can be induced on 2.4-D 1.0mg/l + kinetin 0.1 mg/l and 2.4-D 1.0 mg/l + kinetin 0.3 mg/l, eight to tenweeks after culture. The best medium for shoots regeneration contains 2.4-D 1.0 mg/l + kinetin 0.3 mg/l with 0.3 mg/l BA, with mean result of 13.2shoots and 4.4 leaves.Key words : Rodent tuber, Typonium flagelliforme Lodd. bl , induction,regeneration, calli, in vitro

The aqueous extract of dry onion skin waste from the &lsquo, Dorata di Parma&rsquo, cultivar was tested as a new source of biomolecules for the production of colored and biofunctional wool yarns, through environmentally friendly dyeing procedures. Specific attention was paid to the antioxidant and UV protection properties of the resulting textiles. On the basis of spectrophotometric and mass spectrometry analyses, the obtained deep red-brown color was assigned to quercetin and its glycoside derivatives. The Folin&ndash, Ciocalteu method revealed good phenol uptakes on the wool fiber (higher than 27% for the textile after the first dyeing cycle), with respect to the original total content estimated in the water extract (78.50 &plusmn, 2.49 mg equivalent gallic acid/g onion skin). The manufactured materials showed remarkable antioxidant activity and ability to protect human skin against lipid peroxidation following UV radiation: 7.65 &plusmn, 1.43 (FRAP assay) and 13.60 (ORAC assay) mg equivalent trolox/g textile, lipid peroxidation inhibition up to 89.37%. This photoprotective and antioxidant activity were therefore ascribed to the polyphenol pool contained in the outer dried gold skins of onion. It is worth noting that citofluorimetric analysis demonstrated that the aqueous extract does not have a significative influence on cell viability, neither is capable of inducing a proapoptotic effect.

Oxygenated polyunsaturated fatty acids (PUFAs)play an outstanding role in the physiological and pathological regulation of several biological processes. These oxygenated metabolites can be produced both enzimatically, yielding almost pure enantiomers, and non-enzymatically. The free radical-mediated non-enzymatic oxidation commonly produces racemic mixtures which are used as biomarkers of oxidative stress and tissue damage. The biological activity of oxygenated PUFAs is often associated with only one enantiomer, making it necessary of availing of lipidomics platforms allowing to disclose the role of single enantiomers in health and disease. Polysaccharide-based chiral stationary phases (CSPs) play a dominating part in this setting. As for the cellulose backbone, 4-methylbenzoate derivatives exhibit very high chiral recognition ability towards this class of compounds. Concerning the phenylcarbamate derivatives of cellulose and amylose, the tris(3,5-dimethylphenylcarbamate) variants show the best enantioresolving ability for a variety of oxygenated PUFAs. Moreover, also the amylose tris(5-chloro-2-methylphenylcarbamate)-based selector produces relevant chromatographic performances. The extreme versatility of those CSPs mostly depends on their compatibility with the most relevant elution modes: normal- and reversed-phase, as well as polar organic/ionic-mode. In this review article, a selection of enantioseparation studies of different oxygenated PUFAs is reported, with both tris(benzoates) and tris(phenylcarbamates) of cellulose and amylose.

In this interdisciplinary paper, we study the formation of iron precipitates – the so-called Liesegang rings – in Lecce stones in contact with iron source. These phenomena are responsible of exterior damages of lapideous artifacts, but also in the weakening of their structure. They originate in presence of water, determining the flow of carbonate compounds mixing with the iron ions and then, after a sequence of reactions and precipitation, leading to the formation of Liesegang rings. In order to model these phenomena observed in situ and in laboratory experiments, we propose a modification of the classical Keller–Rubinow model and show the results obtained with some numerical simulations, in comparison with the experimental tests. Our model is of interest for a better understanding of damage processes in monumental stones.

The early diagnosis of cow subclinical mastitis represents a pivotal factor for a prompt and adequate animal treatment. Although several methods are available, the somatic cells count (SCC) still remains the elective test directly carried out on milk samples. In mastitis affected cows (even at subclinical stages), altered concentrations of specific metabolites, including free amino acids, is a well-known occurrence. In order to define the relationships between the variation of the unbound amino acids content with the SCC value, a direct ion-pairing reversed-phase method based on the use of the evaporative light-scattering detector (IP-RP-HPLC-ELSD) was applied to 65 cow milk samples. The statistical analysis of variance (ANOVA) was pursued in order to find a correlation between the SCC value and the concentration of isoleucine (Ile), leucine (Leu), valine (Val) and tyrosine (Tyr). Samples were divided in two groups according to their SCC value: Group I comprised all ones with SCC &lt, 400,000 cells/mL, Group II encompassed those with a SCC &gt, 400,000 cells/mL. Statistical analyses highlighted significant differences in the content of the branched-chain amino acids Ile and Leu, between the two groups (p &lt, 0.02* and &lt, 0.005**, respectively). This study confirms that a dysmetabolism of certain free amino acids parallels elevated SCC values.

The Global Carbon Budget is the cumulative carbon emissions that human activities can generate while limiting the global temperature increase to less than 2°C. On this basis, most countries ratified the Paris Agreement 2015, pledging to reduce national emissions and the impacts of climate change. The European Union has planned to reduce emissions by 80% of their 1990 value by 2050 but such a target needs to be coupled with a further constraint on the cumulative greenhouse gases released along the path to 2050. The aim and the novelty of this study are to propose, for the first time, a carbon budget for the European Union, which represents the most significant physical characteristic to assess the feasibility of current EU-28 greenhouse gas reduction objectives under the goals of the 2015 Paris treaty

In this study, we were interested in comparing the amino acid profile in a specific variety of onion, Rossa da inverno sel. Rojo Duro, produced in two different Italian sites: the Cannara (Umbria region) and Imola (Emilia Romagna region) sites. Onions were cultivated in a comparable manner, mostly in terms of the mineral fertilization, seeding, and harvesting stages, as well as good weed control. Furthermore, in both regions, the plants were irrigated by the water sprinkler method and subjected to similar temperature and weather conditions. A further group of Cannara onions that were grown by micro-irrigation was also evaluated. After the extraction of the free amino acid mixture, an ion-pairing reversed-phase high performance liquid chromatography-evaporative light scattering detector (IP-RP HPLC-ELSD) method allowed for the separation and detection of almost all the standard proteinogenic amino acids. However, only the peaks corresponding to leucine (Leu), phenylalanine (Phe), and tryptophan (Trp), were present in all the investigated samples and they were unaffected from the matrix interfering peaks. The use of the beeswarm/box plots revealed that the content of Leu and Phe were markedly influenced by the geographical origin of the onions (with *** p << 0.001 for Phe), but not by the irrigation procedure. The applied HPLC method was validated in terms of the specificity, the linearity (a logarithm transformation was applied for the method linearization), the limit of detection (LOD) and limit of quantification (LOQ), the accuracy (≥90% for inter-day Recovery percentage), and the precision (≤10.51 for the inter-day RSD percentage), before the quantitative assay of Leu, Phe, and Trp in the onion samples. These preliminary findings are a good starting point for considering the quantity of the specific amino acids in the Rossa da inverno sel. Rojo Duro variety as a fingerprint of its geographical origin.

In the frame of a broader project, we were interested at comparing the amino acid profile in a specific variety of onion, Rossa da inverno sel. Rojo Duro, produced in two different Italian sites: Cannara (Umbria region) and Imola (Emilia Romagna region). In both places, onions were cultivated and harvested in the same way, and irrigated by water sprinkler method. A further group of Cannara onions, growth by microirrigation, was also evaluated. After the extraction of free amino acid mixture from onion samples, an ion-pairing RP-HPLC method allowed the separation and the evaporative light scattering detection of almost all underivatized proteinogenic amino acids. However, only the peaks corresponding to Leu, Phe, Trp, were present in all the investigated samples and unaffected from matrix interfering peaks. The application of the beeswarm/box plots with the ANOVA/TukeyHSD statistical approach revealed a content of Leu and Phe markedly influenced by the geographical origin of the onions, while not by the irrigation procedure. The developed HPLC method was validated in terms of specificity, linearity, LOD and LOQ, accuracy and precision, before the quantitative assay of Leu, Phe and Trp in the onion samples. Although further studies are necessary, these preliminary findings can represent a good starting point for considering the quantity of specific amino acids in the Rossa da inverno sel. Rojo Duro variety as a fingerprint of its geographical origin. In principle, the developed approach might be applied to other onion varieties, thus contributing to their characterization and traceability, also contributing to limit commercial frauds.

In two-dimensional HPLC (2D-HPLC) "heart-cut" applications, two columns are connected in series via a switching valve and volume fractions from the "primary" column are re-injected on the "secondary" column. The heart-cut 2D-HPLC system here described was implemented by connecting a reversed-phase (RP) column (first dimension) to a chiral column (second dimension) containing a quinidine-based chiral stationary phase. The system was used to evaluate the change in the enantiomeric excess value of dansylated (Dns) amino acids (AAs) in milk samples from two cows with different "California Mastitis Test" scores: negative test for sample 1, positive for sample 2. Apart from the co-elution of Dns-Arg/Dns-Gly and the reduced chemoselectivity for Dns-Leu/Dns-allo-Ile, the optimized achiral RP method distinguished the remaining standard Dns-AAs. Dns-AAs were identified in the chromatograms of the real samples, and in higher concentration Dns-Ala, Dns-Arg, Dns-Asp, Dns-Glu, Dns-Ile, Dns-Leu, Dns-Phe and Dns-Val. Except Dns-Arg, the chiral column enabled the RP enantioseparation of all the other compounds (α and RS values up to 1.65 and 8.63, respectively, for Dns-Phe). In sample 2, the amounts of Dns-d-AAs were rather elevated, in particular for Dns-Ala and Dns-Asp. Instead, for sample 1, D-isomers were detected for Dns-Ala, Dns-Glu and Dns-Leu. The proposed 2D-HPLC method could be useful for the identification of clinical mastitis difficult to be diagnosed. Moreover, the eventual progressive reduction of D-AAs levels with the degree of sub-clinical mastitis could allow the building of mathematical models to use for the diagnosis of early stages of mastitis.

Peptide stereoisomer analysis is of importance for quality control of therapeutic peptides, the analysis of stereochemical integrity of bioactive peptides in food, and the elucidation of the stereochemistry of peptides from a natural chiral pool which often contains one or more D-amino acid residues. In this work, a series of model peptide stereoisomers (enantiomers and diastereomers) were analyzed on a zwitterionic ion-exchanger chiral stationary phase (Chiralpak ZWIX(+) 5 µm), in order to investigate the retention and separation performance for such compounds on this chiral stationary phase and elucidate its utility for this purpose. The goal of the study focused on 1) investigations of the effects of the sample matrix used to dissolve the peptide samples; 2) optimization of the mobile phase (enabling deriving information on factors of relevance for retention and separation); and 3) derivation of structure-selectivity relationships. It turned out that small di- and tripeptides can be well resolved under optimized conditions, typically with resolutions larger than 1.5. The optimized mobile phase often consisted of methanol-tetrahydrofuran-water (49:49:2; v/v/v) with 25 mM formic acid and 12.5 mM diethylamine. This work proposes some guidance on which mobile phases can be most efficiently used for peptide stereoisomer separations on Chiralpak ZWIX. Chirality 28:5-16, 2016. © 2015 Wiley Periodicals, Inc.

Onion cultivars with low pungency have been increasing in popularity because they are more attractive for fresh, uncooked use. The pyruvic acid amount is commonly used as a measure of onion pungency. For the first time the validation of a reversed-phase high-performance liquid chromatography method for the quantitative analysis of pyruvic acid in onion extracts was carried out. The established chromatography method based on the use of a 50 mM phosphate buffer (pH 2.5) eluent system provided good precision (RSD% in the range of 1.25–1.29, in the long-period) and accuracy (recovery% in the range of 97.70–111.62, in the long-period) as well as appreciably low limit of detection and limit of quantitation values (11.03 and 33.41 ng/mL, respectively). The validated method proved successful in the analysis of the onion extract from Dorata di Parma cultivar after a preliminary solid-phase extraction step. A significant adherence with results from previous spectrophotometric determinations turned out.

During the last twenty years, the interest towards the development of chiral compound has exponentially been increased. Indeed, the set-up of suitable asymmetric enantioselective synthesis protocols is currently one of the focuses of many pharmaceutical research projects. In this scenario, chiral HPLC separations have gained great importance as well, both for analytical- and preparative-scale applications, the latter devoted to the quantitative isolation of enantiopure compounds. Molecular modelling and quantum chemistry methods can be fruitfully applied to solve chirality related problems especially when enantiomerically pure reference standards are missing. In this framework, with the aim to explain the molecular basis of the enantioselective retention, we performed computational studies to rationalize the enantiomer elution order with both low- and high-molecular weight chiral selectors. Semi-empirical and quantum mechanical computational procedures were successfully applied in the domains of chiral ligand-exchange and chiral ion-exchange chromatography, as well as in studies dealing with the use of polysaccharide-based enantioresolving materials.

New stable [6,6]-methano cycloadducts and fulleropyrazolines containing electron-withdrawing groups have been obtained by the reaction of ethyl diazopiruvate with [60]fullerene. The results obtained by a sistematic study conducted both in thermal and catalytic conditions have provided crucial indications concerning the mechanism of this important cluster opening process in fullerene chemistry.

Detomidine is an alpha-2-adrenergic agonist widely used in horses. To evaluate changes in muscular energy metabolism caused by detomidine continuous rate infusion in standing horses, six adult animals were submitted to 1 hour 20 μg/kg/hr IV constant rate infusion detomidine. Heart rate, respiratory rate (RR), mean arterial blood pressure, systolic blood pressure, diastolic blood pressure, capillary refill time, rectal temperature, plasma glucose, blood lactate, total plasma protein, packed cell volume (PCV), hemoglobin (Hb), partial arterial pressure of oxygen, partial arterial pressure of carbon dioxide (PaCO 2 ), arterial oxygen saturation, bicarbonate (HCO 3 − ), sodium, potassium, ionized calcium (iCa), arterial oxygen content (CaO 2 ), muscle glycogen, and muscle lactate were recorded before the infusion, after 20, 40, and 60 minutes, when it was discontinued. One last sample was obtained 1 hour after infusion was finished. Four animals were submitted to 1 hour saline infusion as a control group. Constant rate infusion detomidine resulted in significant decrease in HR, RR, PCV, Hb, iCa, CaO 2 , and muscle glycogen in comparison with both baseline and control groups and significant increase in PaCO 2 , blood lactate, and HCO 3 − . Detomidine 20 μg/kg/hr produces minimal clinically significant changes in horses, and it does interfere with energy metabolism through mobilization of muscle glycogen and increase in blood lactate.

The comparison between cathodoluminescence and deep level transient spectroscopy is a powerful tool to analyze the defect formation in implanted materials. In this work aluminium implanted 4H-SiC p+/n diodes are studied. Different structures, implanted with different ion energy and fluencies, are analyzed in order to understand the process related effects. The comparison between the epilayer and the implanted areas shows an increase of the concentration of intrinsic defects in the implanted areas. The 4H-SiC band-edge emission decreases, increasing the aluminium ion dose, due to the enhancement of the lattice disorder, partially recovered by the post-implantation annealing.

A new partial differential model for monitoring and detecting copper corrosion products (mainly brochantite and cuprite) is proposed to provide predictive tools suitable for describing the evolution of damage induced on bronze specimens by sulfur dioxide (SO2) pollution. This model is characterized by the movement of a double free boundary. Numerical simulations show a nice agreement with experimental result. (C) 2014 Elsevier Inc. All rights reserved.

Parkinson's disease is a multifactorial neurodegenerative disorder, characterized by a reduction of dopamine (DA) levels. The molecular pathways involved in the pathogenesis of disease have not yet been fully disclosed. Therefore, developing new diagnostic methods and tools to evaluate the depletion of DA and of some of its metabolites (3,4-dihydroxyphenylacetic acid, homovanillic acid, and 3-methoxytyramine) is of outstanding importance for biochemical evaluations. Moreover, neurons responsible for DA release also produce the neurotransmitter gamma-aminobutyric acid (GABA), thus, quantitative measurements of GABA levels can have a relevant impact for a further understanding of the biochemical processes involved in the neurodegenerative event. In the present study, two HPLC methods based on the reversed-phase ion-pairing chromatography (RP-IPC) and the hydrophilic liquid interaction chromatography (HILIC) concepts were developed to allow the quantification of DA and its metabolites as well as GABA levels in mouse striatal and cortical tissue homogenates. The two fairly orthogonal HPLC methods were directly applied to the biological samples, without preliminary derivatization of the compounds of interest. A high level of selectivity was obtained for DA metabolites and GABA by running the gradient RP-IPC method with a volatile ion-pairing reagent, which makes it suitable for the quantitative assay of four out of five compounds. Matrix deriving interferences unabled the base-line separation of DA which was instead successfully achieved with the HILIC-based method. To avail of HPLC methods providing distinct selectivity profiles, makes possible the correct species quantification and allows to compensate the intrinsic limits characterizing all chromatographic methods.

With the present contribution, we demonstrate that the baseline separation of ketoprofen enantiomers can be successfully achieved (α = 1.09; R(S) = 1.60) in the reversed-phase mode of elution with a commercially available anion-exchange-based chiral stationary phase, incorporating the quinine 2,6-diisopropylphenyl carbamate derivative as the enantioresolving unit. Focused modification of the eluent composition indicated a stereoselective role of hydrophobic and π-π interactions between the selector and selectand units, besides the prime ionic intermolecular interaction. The mechanistic hypotheses based on the chromatographic data were confirmed by in silico molecular dynamic simulations, which allowed us to establish the network of selector-selectand interactions underlying the stereorecognition process at a molecular level. The validated method was successfully used to evaluate the drug content and release profile of ketoprofen-loaded polymeric film, showing drug homogeneous distribution into the film and no preferential interactions between the polymer and one of the enantiomers, with the racemate released at each time point.

For the first time, a successful chromatographic method based on the use of a novel triazole click quinidine (QD) derivative anion-exchange chiral stationary phase (CSP) is applied for the epimer separation of dafachronic acids (Δ 4 - and Δ 7 -DAs). The use of a polar-ionic eluent system consisting of 18 mM AcOH in ACN furnished an excellent separation of both Δ 4 - ( α = 1.19, R S = 2.52) and Δ 7 -DA ( α = 1.14, R S = 2.06) C-25 epimer couples. The pool of data collected during the chromatographic analyses revealed the prominent role of anion-exchange interactions in governing the analyte (SA) retention and also indicated the occurrence of stereoselective H-bond contacts with the chiral selector (SO) substructural motifs. In any case, molecular modelling studies corroborate the need for sufficient spatial freedom for optimum binding between the SO and the SAs which seems less the case for the immobilised SO unit of the commercialized QD-based CSP.

A dynamic coating of the RP-18 carbon chain layers with the new chiral selector (S)-(-)-alpha,alpha-di(2-naphthyl)-2-pyrrolidinemethanol allowed the formation of a mixed chiral stationary phase that has been used in the separation of a selected set of amino acid racemates. Both a representative model and classification structure-property relationship studies have been performed in order to study the contribution of hydrophobic, bulky and electron-donating groups in the side chain of the chiral selector to the mechanism of chiral recognition.

Mobile phase variables have a deep influence on the chromatographic behavior with polysaccharide-based chiral stationary phases. Basic additives are generally used to minimize peak broadening arising from unwanted interactions between polar solutes and underivatized silanols. However, basic additives can improve enantioselectivity through disruption of hydrogen bonds and modification of the polymer morphology. Acidic additives are incorporated into the mobile phase during the analysis of acidic compounds as efficiency enhancers. Acidic additives can also improve enantioselectivity by minimizing within the chiral recognition site nonenantioselective retention. Peak shape without acidic additive in the eluent could be severely distorted during the analysis of salified compounds. Concentration and type of alcohol modifier can have an effect on the morphology of the polymer. The different winding of the chiral selector, caused by alcohol modifiers of different size/shape, ultimately results in different stereo environment of the chiral cavities in the polymer chain. Trace amounts of water in normal-phase eluents can affect retention time, tailing, and resolution. Deliberate addition of water to the eluent can improve peak resolution and save analysis time and solvent needs. Immobilized-type polysaccharide-derived chiral stationary phases offer new selectivity profiles and often improved enantioselectivity.

Recent evidences demonstrate that branched-chain amino acids (BCAAs) are associated with a number of pathologies encompassing insulin resistance, type 2 diabetes mellitus, chronic kidney disease as well as ischemic stroke, major depression and Huntington disease. Therefore, the measurement and monitoring of BCAAs levels in biological fluids and organs could represent a promising method for aiding in the clinical diagnosis and prognosis assessment for patients. However, too many questions are still open regarding the mechanisms at the basis of the relationship between BCAAs levels and disease process/severity. It is widely accepted that BCAAs levels in diagnosing, predicting or monitoring disease can be concretely useful in the presence of additional information that will place these levels in the context of the whole clinical picture.

The capacity of nonsteroidal antiinflammatory drugs (NSAIDs) to prevent prostanoids biosynthesis through the inhibition of COX-2 enzyme is related to their structural backbone, based on the fusion of a cis-stilbene unit with a variety of heterocyclic and carbocyclic rings. By this route, a series of new selective COX-2 inhibitors was developed, by maintaining the 4-methylsulfone or 4-methylsulfonamide substituent on the phenyl moiety, essential for their activity. In this frame, two novel propyl sulfoxide derivatives were synthesized, which proved selective and sufficiently potent COX-2 inhibition activity when tested as racemates. In the present study, the use of a cellulose tris(3,5-dichlorophenylcarbamate)-based chiral stationary phase, in a polar-organic mode of elution, enabled the successful enantioseparation of the investigated compounds. The developed chromatography method reveals a useful tool of monitoring in view of a proper forthcoming enantioselective synthetic protocol. Moreover, the optimized chromatographic conditions allowed the isolation of appropriate amounts of single enantiomers for the electronic circular dichroism studies that, coupled with in silico simulations, allowed assessing the absolute configuration of each species.

Tomatoes are important sources of vitamins, minerals, and bioactive molecules. The fresh cut industry is interested in including tomatoes among the fresh cut vegetables. The wounds usually induce tissue degradation and release of juice, which can negatively affect quality during storage. The aim of this work was to investigate the role of ethylene in the processed vegetables using the never ripe (Nr) mutant and wild type tomatoes. The ethylene accumulation affected shelf life and quality based on the differential sensitivity of the genotypes to ethylene. Physiological and biochemical parameters related to membrane stability, phospholipases activities, ethylene and carbon dioxide accumulation were investigated in Nr mutant and wild type tomatoes as processed products and whole fruits. Results indicate that ethylene biosynthesis significantly regulates membrane breakdown. Nr tomatoes showed higher membrane stability, higher tolerance to wounding, and lower variability of physiological and biochemica...