Carbonyl compounds responsive 2,4-dinitrophenylhydrazine doped polydimethylsiloxane based membrane as alternative derivatizing strategy prior to in-tube solid phase microextraction coupled with capillary liquid chromatography analysis.

In this work, a DNPH doped PDMS based membrane was developed to facilitate carbonyl compound derivatization. This membrane delivers DNPH in presence of carbonyl compounds to form hydrazones. Subsequently, the resulting hydrazones are preconcentrated, separated and detected by in-tube solid phase microextraction (IT-SPME) coupled on-line with capillary liquid chromatography (CapLC) with Uv-Vis diode array detection (DAD).

High-pressure phase transition and amorphization of BaVO.

The structural evolution of metavanadate compounds under high pressure offers valuable insights into phase transitions and changes in material properties. This study explores the structural behavior of BaVO under pressures up to 12 GPa using powder X-ray diffraction and density-functional theory (DFT) simulations. The results indicate a phase transition from the ambient pressure orthorhombic phase (space group 222) to a monoclinic phase (space group 2) at 4 GPa, likely driven by the distortion of the vanadium oxide polyhedron.

The Impact of Corneal Oedema on UV Light Transmission: An Experimental Study in Porcine Eyes.

Corneal oedema is known for changing the cornea's optical properties, particularly its ability to transmit ultraviolet (UV) light, which is crucial for visual clarity and eye health. This study explores how changes in corneal thickness in oedematous states affect UV light transmission. This study included 107 porcine eyes with artificially induced corneal oedema.

Quantitative Assessment of Volatile Profile and Sensory Perception of Artisan Bread Made in the City of Valencia.

Artisan bread, known for its simple recipes, natural ingredients, and traditional techniques, has seen a surge in demand, especially following the COVID-19 pandemic. Small bakeries emphasize extended fermentation processes and prioritize sensory qualities in their products. However, the impact of ingredients on the quality characteristics of artisan bread remains underexplored.

Acrylamide content in popcorn from Spanish market: Risk assessment.

Snacks, including popcorn, are increasingly consumed in Spain and are susceptible to acrylamide (AA) formation. AA, classified as a probable human carcinogen by the International Agency for Research on Cancer (IARC), is produced via the Maillard reaction between reducing sugars and amino acids, particularly glucose, and asparagine, when foods are heated above 120 °C. This study aims to analyze the AA content in 91 popcorn samples, categorized by flavor (salted, butter, caramel, flavored, colored, unflavored) and cooking method (ready-to-eat, popcorn maker, microwave), and assess dietary AA exposure in the Spanish population.

In vivo detection of spectral reflectance changes associated with regulated heat dissipation mechanisms complements fluorescence quantum efficiency in early stress diagnosis.

Early stress detection of crops requires a thorough understanding of the signals showing the very first symptoms of the alterations in the photosynthetic light reactions. Detection of the activation of the regulated heat dissipation mechanism is crucial to complement passively induced fluorescence to resolve ambuiguities in energy partitioning. Using leaf spectroscopy, we evaluated the capability of pigment spectral unmixing to calculate the fluorescence quantum efficiency (FQE) and simultaneously retrieve fast absorption changes in a drought and nitrogen deficiency experiment with tomato.

Thermal equation of state of rhodium characterized by XRD in a resistively heated diamond anvil cell.

The high-pressure and high-temperature structural, mechanical, and dinamical stability of rhodium has been investigated via synchrotron X-ray diffraction using a resistively heated diamond anvil cell and density functional theory. The isothermal compression data have been fitted with a Rydberg-Vinet equation of state (EoS) with best-fitting parameters =55.046(16) Å , = 251(3) GPa, and = 5.

Correlation Between Voltammetry of Immobilized Particles and Mott-Schottky Analysis of Metal Corrosion Patinas.

The conjoint application of the voltammetry of immobilized particles (VIMP) methodology and the Mott-Schottky analysis (MS) of impedance data to studying metal corrosion patinas is described. The study is applied to copper and bronze objects exploiting the semiconducting character of cuprite and other copper corrosion products. A simplified theoretical modeling of MS analysis at microparticulate deposits extracted from metal corrosion layers attached to graphite electrodes is provided.

Danio rerio embryo as in vivo model for the evaluation of the toxicity and metabolism of pyrovalerone cathinones.

The objective of the present manuscript was the evaluation of the toxicity and metabolism of the second generation of pyrovalerone cathinones (α-PHP, α-PHPiP, 4-MePPP and TH-PVP), using an early zebrafish (Danio rerio) larvae as in vivo model. Pyrovalerone cathinones LC were determined after 24, 48, 72 and 96 h of exposure. TH-PVP proved to be the most toxic cathinone, whereas 4-MePPP was the least toxic.

Transferability of global retention models in reversed-phase liquid chromatography for natural products.

Considerable progress has been made in enhancing resolution in reversed-phase liquid chromatography for the analysis of complex samples, particularly within the field of natural products, through the application of global retention models using multi-linear gradients. Global models effectively differentiate solute retention effects from those originating from the column and solvent, offering predictive capabilities comparable to conventional individual retention models, without the requirement for standards for all compounds. While conventional individual models result in higher accuracy, they frequently demand standards that are unavailable for natural product samples.

Asymmetric electrophilic functionalization of amino-substituted heteroaromatic compounds: a convenient tool for the enantioselective synthesis of nitrogen heterocycles.

The catalytic asymmetric electrophilic functionalization of the less reactive N-heteroaromatic compounds has been reported using the approach of the introduction of an exocyclic amino substituent. This strategy has allowed enantioselective Friedel-Crafts alkylation in pyrazoles, isoxazoles and isothiazoles, as well as in aminoindoles, aminobenzofurans and aminobenzothiophenes. Several stereoselective methods have been used for the 1,4-addition or 1,2-addition of these heteroaromatic compounds to different electrophiles employing organocatalysts or chiral metal complexes.

Absolute Configuration of the Invasive Mealybug (De Lotto) Sex Pheromone: Synthesis and Bioassay of Both Enantiomers.

The mealybug (De Lotto) (Hemiptera: Pseudococcidae) is an invasive pest reported in Europe at the end of the first decade of the 2000s, causing severe damage to citrus production in eastern Spain. In a previous work, (4,5,5-trimethyl-3-methylenecyclopent-1-en-1-yl)methyl acetate was identified as the sex pheromone emitted by females, a new compound with an unusual β-necrodol skeleton possessing one stereocenter. This compound was assigned to the (-)-enantiomer but the absolute configuration was then not reported.

Assessing the size transformation of nanoplastics in natural water matrices.

Understanding the stability of NPs in different aqueous environments, related with their size is crucial for assessing their potential risks. This is influenced by several factors, including pH, ionic strength, and the presence of biomolecules, or dissolved organic matter (DOM). In this study, dispersions of NPs derived from common plastic waste materials, including polystyrene (PS), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), and polycarbonate (PC), were synthesized by a nanoprecipitation method with sizes: 189 ± 7, 58 ± 3, 123 ± 4, 151 ± 7 and 182 ± 6 nm, respectively.

Electrogeneration and Characterization of Poly(methylene blue) Thin Films on Stainless Steel 316 Electrodes-Effect of pH.

Methylene blue was electropolymerized on the surface of stainless steel 316. The addition of sodium oxalate and working at a pH near 11 allowed us to obtain steel electrodes coated with an electroactive polymer. This polymer shows electrochromic properties like those of the monomer, but also exhibits electroactivity at more positive potentials, which is associated with the active centers in the bridges between monomeric units.

Janus ScYCBr MXene as a Promising Thermoelectric Material.

Finding green energy resources that contribute to the battle against global warming and the pollution of our planet is an urgent challenge. Thermoelectric electricity production is a clean and efficient method of producing energy; consequently, scientists are currently researching and creating thermoelectric materials to increase the efficiency of thermoelectric electricity production and expand the potential of the thermoelectric effect for clean energy production. This work focuses on a comprehensive study of the thermoelectric properties of two-dimensional ScYCBr.

Performance of global retention models in the optimisation of the liquid chromatographic separation (II): Complex multi-analyte samples.

Background: Enhancing the quality control of medicinal plants is a complex challenge due to their rich variety of chemical compounds present at varying and extreme concentrations. Chromatographic fingerprints, which have become essential for characterising these complex natural materials, require achieving optimal separation conditions to effectively maximise the number of detected peaks. The challenges in optimising fingerprints and other complex multi-analyte samples include the unavailability of standards, the presence of unknown constituents and the substantial workload that would require conventional optimisation methods based on models.

Transcriptional reprogramming post-peripheral nerve injury: A systematic review.

Neuropathic pain is characterised by periodic or continuous hyperalgesia, numbness, or allodynia, and results from insults to the somatosensory nervous system. Peripheral nerve injury induces transcriptional reprogramming in peripheral sensory neurons, contributing to increased spinal nociceptive input and the development of neuropathic pain. Effective treatment for neuropathic pain remains an unmet medical need as current therapeutics offer limited effectiveness and have undesirable effects.

The role of the cation and anion in aqueous liquid chromatography with sodium dodecyl sulphate and imidazolium-based ionic liquids as mobile phase reagents.

Background: In reversed-phase liquid chromatography, solute retention is primarily influenced by interactions between a nonpolar stationary phase and a moderately polar hydro-organic mobile phase, based on the solute lipophilicity. However, challenges regarding retention and peak tailing can arise due to ionic interactions between positively charged analytes and free silanols present on silica-based stationary phases. To address these challenges, incorporating surfactants and ionic liquids (ILs) into the mobile phase offers an effective solution.

Development of a greener and sustainable method to determine acrylamide in corn products by LC-MS/MS: Evaluation of levels in corn-based products.

Acrylamide (AA) is produced through the reaction between sugars and amino acids present in starchy foods cooked at high temperature. It is classified as probably carcinogenic to humans. In 2019, the European Commission reported a list of foods for monitoring the presence of AA, which includes cereal snacks.

Green synthesis of MIL53(Al)-modified paper-based analytical device for efficient extraction of neonicotinoid insecticides from environmental water samples.

Background: There is a need to develop low-cost, reliable and portable devices to enhance the efficiency of microextraction techniques in complex samples. Metal-organic frameworks (MOFs) have proven to be promising sorbents due to their well-documented properties. However, their green preparation and combination with paper-based substrates have not been satisfactorily explored to fabricate sustainable sorptive phases.

Analysis and classification of tea varieties using high-performance liquid chromatography and global retention models.

As a result of their metabolic processes, medicinal plants produce bioactive molecules with significant implications for human health, used directly for treatment or for pharmaceutical development. Chromatographic fingerprints with solvent gradients authenticate and categorise medicinal plants by capturing chemical diversity. This work focuses on optimising tea sample analysis in HPLC, using a model-based approach without requiring standards.

A Macroscopic Interpretation of the Correlation between Electrical Percolation and Mechanical Properties of Poly-(Ethylene Vinyl Acetate)/Zn Composites.

Elastic composites were prepared using a procedure involving hot plates and zinc powder that was directly dispersed into an EVA matrix. The correlation between the zinc content and the conductive properties of the material was studied via impedance spectroscopy, the thermal properties of the material were studied via differential calorimetry and the mechanical properties of the composites were studied via tensile strength curves, representing an important advancement in the characterization of this type of composite material. The composites' tensile strength and elongation at break decrease with the addition of filler since zinc particles act as stress-concentrating centres, while the composites' hardness and Young's modulus increase because of an increase in the stiffness of the material.

Molecular Data Confirm Interspecific Limits of Four and One Species of Parasitic Wasps within the Subfamily Charipinae (Cynipoidea: Figitidae).

The hymenopteran subfamily Charipinae (Cynipoidea: Figitidae) consist of a group of parasitic wasps that are exclusive hyperparasitoids of Hemipteran. The species boundaries in Charipinae have historically been unclear. While diagnostic morphological features have been established for the stepwise separation of species, it is recommended to confirm those limits using molecular data.

New Monoterpenoid as the Sex Pheromone of Spanish Populations of the Longtailed Mealybug (Hemiptera: Pseudococcidae).

(Targioni-Tozzetti) (Hemiptera: Coccoidea: Pseudococcidae), a polyphagous and cosmopolitan pest native to Australia, is a highly damaging pest for numerous crops of economic importance. The sex pheromone of this species (2-(1,5,5-trimethylcyclopent-2-en-1-yl)ethyl acetate), currently used for pest monitoring purposes, was not attractive to males in field experiments conducted in Spanish persimmon orchards infested with this mealybug. The virgin and mated female volatile profiles of these populations were studied by the volatile collection of effluvia in Porapak-Q.