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Aim: Liver‐expressed antimicrobial peptide 2 (LEAP2) dynamics in human plasma and its association with feeding behaviour remain poorly understood. Therefore, this study aims: (a) to investigate fasting LEAP2 in participants with normal weight or with overweight or mild obesity (OW/OB); (b) to study the association between fasting LEAP2 and anthropometric and metabolic traits, feeding behaviour, LEAP2 genetic variants and blood cell DNA methylation status; and (c) to ascertain postprandial changes in LEAP2 after high protein intake and the association with feeding behaviour and food intake. Methods: Anthropometric and behavioural measures, genotyping, methylation profiling, plasma glucose and LEAP2 concentrations were assessed in 327 females and males. A subgroup of 123 participants received an ad libitum high‐protein meal, and postprandial LEAP2 concentration and behavioural measures were assessed. Results: LEAP2 concentration was higher in participants with OW/OB (p < 0.001) and in females (p < 0.001), and was associated with LEAP2 single nucleotide polymorphisms rs765760 (p = 0.012) and rs803223 (p = 0.019), but not with LEAP2 methylation status. LEAP2 concentration was directly related to glycaemia (p = 0.001) and fullness (p = 0.003) in participants with normal weight, whereas it was associated with body mass index (p = 0.018), waist circumference (p = 0.014) and motor impulsivity in participants with OW/OB (p = 0.005). A negative association with reward responsiveness was observed in participants with OW/OB (p = 0.023). LEAP2 concentration was inversely associated with food intake (p = 0.034) and decreased after a high‐protein meal (p < 0.001), particularly in women (p = 0.002). Conclusion: Increased LEAP2 in participants with OW/OB is associated with behavioural characteristics of obesity. Our results show sexual dimorphism in LEAP2 concentration before and after food intake and highlight the role of LEAP2 in feeding regulation. [ABSTRACT FROM AUTHOR]

Amino‐acid protein composition plays an important role in biology, medicine, and nutrition. Here, a groundbreaking protein analysis technique that quickly estimates amino acid composition and secondary structure across various protein sizes, while maintaining their natural states is introduced and validated. This method combines multivariate statistics and the thermostable Raman interaction profiling (TRIP) technique, eliminating the need for complex preparations. In order to validate the approach, the Raman spectra are constructed of seven proteins of varying sizes by utilizing their amino acid frequencies and the Raman spectra of individual amino acids. These constructed spectra exhibit a close resemblance to the actual measured Raman spectra. Specific vibrational modes tied to free amino and carboxyl termini of the amino acids disappear as signals linked to secondary structures emerged under TRIP conditions. Furthermore, the technique is used inversely to successfully estimate amino acid compositions and secondary structures of unknown proteins across a range of sizes, achieving impressive accuracy ranging between 1.47% and 5.77% of root mean square errors (RMSE). These results extend the uses for TRIP beyond interaction profiling, to probe amino acid composition and structure. [ABSTRACT FROM AUTHOR]

Background: Trigeminal neuralgia (TN) is a severe facial pain condition often associated with a neurovascular conflict. However, neuroinflammation has also been implicated in TN, as it frequently co‐occurs with multiple sclerosis (MS). Methods: We analysed protein expression levels of TN patients compared to MS patients and controls. Proximity Extension Assay technology was used to analyse the levels of 92 proteins with the Multiplex Neuro‐Exploratory panel provided by SciLifeLab, Uppsala, Sweden. Serum and CSF samples were collected from TN patients before (n = 33 and n = 27, respectively) and after (n = 28 and n = 8, respectively) microvascular decompression surgery. Additionally, we included samples from MS patients (n = 20) and controls (n = 20) for comparison. Results: In both serum and CSF, several proteins were found increased in TN patients compared to either MS patients, controls, or both, including EIF4B, PTPN1, EREG, TBCB, PMVK, FKBP5, CD63, CRADD, BST2, CD302, CRIP2, CCL27, PPP3R1, WWP2, KLB, PLA2G10, TDGF1, SMOC1, RBKS, LTBP3, CLSTN1, NXPH1, SFRP1, HMOX2, and GGT5. The overall expression of the 92 proteins in postoperative TN samples seems to shift towards the levels of MS patients and controls in both serum and CSF, as compared to preoperative samples. Interestingly, there was no difference in protein levels between MS patients and controls. Conclusions: We conclude that TN patients showed increased serum and CSF levels of specific proteins and that successful surgery normalizes these protein levels, highlighting its potential as an effective treatment. However, the similarity between MS and controls challenges the idea of shared pathophysiology with TN, suggesting distinct underlying mechanisms in these conditions. Significance: This study advances our understanding of trigeminal neuralgia (TN) and its association with multiple sclerosis (MS). By analysing 92 protein biomarkers, we identified distinctive molecular profiles in TN patients, shedding light on potential pathophysiological mechanisms. The observation that successful surgery normalizes many protein levels suggests a promising avenue for TN treatment. Furthermore, the contrasting protein patterns between TN and MS challenge prevailing assumptions of similarity between the two conditions and point to distinct pathophysiological mechanisms. [ABSTRACT FROM AUTHOR]

The low energy interactions between axions and electromagnetic fields that arise in models with heavy dyons charged under a spontaneously broken global axial U(1) symmetry are derived using the path integral approach. Hence, generic axion‐Maxwell equations relevant for experimental searches are obtained. It is found that the structure of the axion Maxwell equations can be significantly different compared to what is normally assumed in the literature, as the derived equations feature new axion‐dependent terms including CP‐violating ones. The new terms can reconcile the Peccei–Quinn solution to the strong CP problem with astrophysical axion hints, as well as give unique signatures in light‐shining‐through‐wall and haloscope experiments. Moreover, via the latter signatures, these experiments can indirectly probe the existence of heavy dyons. [ABSTRACT FROM AUTHOR]

Recently, interactions between putative axions and magnetic monopoles have been revisited by two of the authors.[1] It is shown that significant modifications to conventional axion electrodynamics arise due to these interactions, so that the axion–photon coupling parameter space is expanded from one parameter gaγγ$g_{a\gamma \gamma }$ to three (gaγγ,gaAB,gaBB)$(g_{a\gamma \gamma },g_{aAB},g_{aBB})$. Poynting theorem is implemented to determine how to exhibit sensitivity to gaAB$g_{aAB}$ and gaBB$g_{aBB}$ using resonant haloscopes, allowing new techniques to search for axions and a possible indirect way to determine if magnetically charged matter exists. [ABSTRACT FROM AUTHOR]

The magnetoelectric (ME) effect is beginning to be extensively studied. However, the main issue in the design of new ME devices is the evaluation and selection of the ME composite and the calculation of its ME voltage coefficients. As the calculation of ME voltage coefficients based on the generalized Hooke's law is a laborious task, the well‐known method of nomograms is presented to simplify it. To attract the further interest of researchers in this field toward the nomogram method, this article presents a detailed method to obtain the ME voltage coefficients of two ME composites: nickel spinel (NFO)–lead zirconate titanate (PZT) and Terfenol‐D–piezoquartz (X‐cut) in the low‐frequency range and the longitudinal mode of electromechanical resonance (EMR). The results confirm that the nomogram method, in contrast to the general method, allows a quicker and easier determination of the ME voltage coefficients with considerable accuracy. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (GNPs) have shown considerable potential in a vast number of biomedical applications. However, currently there are no clinically approved injectable GNP formulations. Conversely, gold salts have been used in the clinic for nearly a century. Further, there is evidence of GNP formation in patients treated with gold salts (i.e., chrysiasis). Recent reports evaluating this phenomenon in human cells and in murine models indicate that the use of gold ions for in situ formation of theranostic GNPs could greatly improve the delivery within dense biological tissues, increase efficiency of intracellular gold uptake, and specificity of GNP formation within cancer cells. These attributes in combination with safe clinical application of gold salts make this process a viable strategy for clinical translation. Here, the first summary of the current knowledge related to GNP biomineralization in mammalian cells is provided along with critical assessment of potential biomedical applications of this newly emergent field. [ABSTRACT FROM AUTHOR]

Background: While microbubble contrast agents (MCAs) are commonly used in ultrasound (US), they are inherently limited to vascular targets due to their size. Alternatively, phase‐changing nanodroplet contrast agents (PNCAs) can be delivered as nanoscale agents (i.e., small enough to extravasate), but when exposed to a US field of sufficient mechanical index (MI), they convert to MCAs, which can be visualized with high contrast using nonlinear US. Purpose: To investigate the effect of perfluorocarbon (PFC) core composition and presence of cholesterol in particle coatings on stability and image contrast generated from acoustic activation of PNCAs using high‐frequency US suitable for clinical imaging. Methods: PNCAs with varied core compositions (i.e., mixtures of perfluoropentane [C5] and/or perfluorohexane [C6]) and two coating formulations (i.e., with and without cholesterol) were characterized and investigated for thermal/temporal stability and postactivation, nonlinear US contrast in phantom and in vivo environments. Through hydrophone measurements and nonlinear numerical modeling, MI was estimated for pulse sequences used for PNCA activation. Results: All PNCA compositions were characterized to have similar diameters (249–267 nm) and polydispersity (0.151–0.185) following fabrication. While PNCAs with majority C5 core composition showed higher levels of spontaneous signal (i.e., not due to US activation) in phantoms than C6‐majority PNCAs, all compositions were stable during imaging experiments. When activating PNCAs with a 12.3‐MHz US pulse (MI = 1.1), C6‐core particles with cholesterol‐free coatings (i.e., CF‐C6‐100 particles) generated a median contrast of 3.1, which was significantly higher (p < 0.001) than other formulations. Further, CF‐C6‐100 particles were activated in a murine model, generating US contrast ≥$ \ge $3.4. Conclusion: C6‐core PNCAs can provide high‐contrast US imaging with minimal nonspecific activation in phantom and in vivo environments. [ABSTRACT FROM AUTHOR]

Hydroxyisophthalic acids are valuable polytopic ligands for the design of functional materials based on coordination polymers due to the variety of charges and coordination modes they possess. Herein, we describe the synthesis, thermal stability, nonlinear optical (NLO) and spectroscopic properties of five novel coordination compounds, [K2L(H2O)2], [MgL(H2O)2] ⋅ 3H2O, [CaL(H2O)3], [SrL(H2O)3] ⋅ H2O, [BaL(H2O)(H2O)5], and one salt, (NH4)2L ⋅ 2H2O, with 4,5,6‐trihydroxyisophthalic acid (H2L), which has not been tested in assembling crystalline coordination networks before. The peculiarities of the structural organization of the compounds were analyzed and compared with those for other hydroxyisophthalates. The coordination properties of hydroxyisophthalic acids were studied from the topological point of view, and a comparative topological analysis of coordination and H‐bonded networks was performed. Structural correlations revealed in this study could be useful for the design of hydroxyisophthalate‐based coordination networks, including porous metal‐organic frameworks, proton conductors, and NLO materials. [ABSTRACT FROM AUTHOR]

In this work nine novel heteroleptic Ir(III) complexes of general formulae [Ir(N∧C#)2(O∧O#)] containing four different cyclometallating and four β‐diketonate ligands were synthesized and fully characterized. Six of them display phosphorescence in the deep red and NIR regions with quantum yields reaching 24.6 % in degassed solution for one of the NIR emitters. Variation in the nature of orthometalating ligands results in dramatic changes in photophysical behavior: the compounds containing 2‐phenylpyridine (N∧C1) and 2‐(benzo[b]thiophen‐2‐yl)pyridine (N∧C2) ligands give non‐emissive complexes, whereas those with methyl 2‐phenylquinoline‐4‐carboxylate (N∧C3) and 6‐(benzo[b]thiophen‐2‐yl)phenanthridine) (N∧C4) are luminescent, but display different character of electronic transitions responsible for absorption and emission. Complexes with the N∧C3 ligand luminesce from 3LC excited state and do not change their emission characteristics upon variations in the nature of β‐diketonates. On the contrary, the compounds based on the N∧C4 cyclometalating ligand emit from the excited state with considerable contribution of 3MLCT character and show systematic bathochromic shift of absorption and emission bands upon increase in electron donicity of O∧O# ligands. This conclusion was supported by DFT and TD‐DFT calculations and by the analysis of correlations between the 13C chemical shift of the diketonate C(H) carbon and emission maxima of the compounds under study. [ABSTRACT FROM AUTHOR]

Designing peptide sequences that self‐assemble into well‐defined nanostructures can open a new venue for the development of novel drug carriers and molecular contrast agents. Current approaches are often based on a linear block‐design of amphiphilic peptides where a hydrophilic peptide chain is terminated by a hydrophobic tail. Here, a new template for a self‐assembling tetrapeptide (YXKX, Y = tyrosine, X = alkylated tyrosine, K = lysine) is proposed with two distinct sides relative to the peptide's backbone: alkylated hydrophobic residues on one side and hydrophilic residues on the other side. Using all‐atom molecular dynamics simulations, the self‐assembly pathway of the tetrapeptide is analyzed for two different concentrations. At both concentrations, tetrapeptides self‐assembled into a nanosphere structure. The alkylated tyrosines initialize the self‐assembly process via a strong hydrophobic effect and to reduce exposure to the aqueous solvent, they formed a hydrophobic core. The hydrophilic residues occupied the surface of the self‐assembled nanosphere. Ordered arrangement of tetrapeptides within the nanosphere with the backbone hydrogen bonding led to a beta sheet formation. Alkyl chain length constrained the size and shape of the nanosphere. This study provides foundation for further exploration of self‐assembling structures that are based on peptides with hydrophobic and hydrophilic moieties located on the opposite sides of a peptide backbone. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAbs) against morphine are important in the development of immunotherapeutic and diagnostic methods for the treatment and prevention of drug addiction. By the surface plasmon resonance (SPR) and enzyme immunoassay techniques, we characterized two previously obtained mAbs 3K11 and 6G1 and showed their ability to recognize free morphine and morphine‐containing antigens in different ways because of the epitope specificity thereof. Using the defined amino acid sequences, we obtained three‐dimensional models of the variable regions of Fab fragments of these antibodies and compared them with the known sequence and spatial structure of the anti‐morphine antibody 9B1. Docking simulations are performed to obtain models of the antibodies complexes with morphine. Differences in the models of 3K11 and 6G1 complexes with morphine correlate with their experimentally detected epitope specificity. The results, in particular, can be used for the structure‐based design of the corresponding humanized antibodies. According to our modeling and docking results, the very different modes of morphine binding to mAbs 3K11 and 6G1 are qualitatively similar to those previously reported for cocaine and two anti‐cocaine antibodies. Thus, the obtained structural information brings more insight into the hapten recognition diversity. [ABSTRACT FROM AUTHOR]

The paper describes the magnetoelectric (ME) effect in a gradient laminate structure consisting of a LiNbO3/Ni/metglas multilayer based on a bidomain lithium niobate single crystal with a Y + 128° cut. The main purpose of the work is to obtain a self‐biased structure. A theoretical and experimental study is conducted to determine the optimal thickness of the Ni film for creating such a structure. The application of self‐biased structures based on gradient bidomain crystals in ME devices can significantly reduce their weight and dimensions as well as improve their electrical characteristics. [ABSTRACT FROM AUTHOR]

Purpose: Design and characterization of a new inductively driven wireless coil (WLC) for wrist imaging at 1.5 T with high homogeneity operating due to focusing the B1 field of a birdcage body coil. Methods: The WLC design has been proposed based on a volumetric self‐resonant periodic structure of inductively coupled split‐loop resonators with structural capacitance. The WLC was optimized and studied regarding radiofrequency fields and interaction to the birdcage coil (BC) by electromagnetic simulations. The manufactured WLC was characterized by on‐bench measurements and in vivo and phantom study in comparison to a standard cable‐connected receive‐only coil. Results: The WLC placed into BC gave the measured B 1 + increase of the latter by 8.6 times for the same accepted power. The phantom and in vivo wrist imaging showed that the BC in receiving with the WLC inside reached equal or higher signal‐to‐noise ratio than the conventional clinical setup comprising the transmit‐only BC and a commercial receive‐only flex‐coil and created no artifacts. Simulations and on‐bench measurements proved safety in terms of specific absorption rate and reflected transmit power. Conclusions: The results showed that the proposed WLC could be an alternative to standard cable‐connected receive coils in clinical magnetic resonance imaging. As an example, with no cable connection, the WLC allowed wrist imaging on a 1.5 T clinical machine using a full‐body BC for transmitting and receive with the desired signal‐to‐noise ratio, image quality, and safety. [ABSTRACT FROM AUTHOR]

Nafion particles doped with ruthenium(II) tris(2,2′-bipyridyl) are synthesized by using a re-precipitation method. Characterization including SEM sizing and quantification of Ru(bpy)32+ in the Nafion particles using UV/Vis spectroscopy was conducted. The synthesized Ru-Nafion particles were investigated electrochemically at both ensemble and single particle levels. Voltammetry of the drop-cast Ru-Nafion particles evidences the successful incorporation of Ru(bpy)32+ into the Nafion particle but only a small fraction of the incorporated Ru(bpy)32+ was detected due at least in part to the formation of the likely agglomerated and irregular 'mat' associated with the dropcast technique. In contrast, nano-impact experiments provided a quantitative determination of the amount of Ru(bpy)32+ in single Ru-Nafion particles. Finally, oxidation of solution-phase oxalate mediated by Ru(bpy)32+ within individual Nafion particles was observed, showing the electrocatalytic properties of the Ru-Nafion particles. [ABSTRACT FROM AUTHOR]

The oxidative dissolution of citrate-capped silver nanoparticles (AgNPs, ∼50 nm diameter) is investigated herein by two electrochemical techniques: nano-impacts and anodic stripping voltammetry. Nano-impacts or single nanoparticle-electrode collisions allow the detection of individual nanoparticles. The technique offers an advantage over surface-immobilized methods such as anodic stripping voltammetry as it eliminates the effects of particle agglomeration/aggregation. The electrochemical studies are performed in different electrolytes (KNO3, KCl, KBr and KI) at varied concentrations (≤20 m m). In nano-impact measurements, the AgNP undergoes complete oxidation upon impact at a suitably potentiostated electrode. The frequency of the nanoparticle-electrode collisions observed as current-transient spikes depends on the electrolyte identity, its concentration and the potential applied at the working electrode. The frequencies of the spikes are significantly higher in the presence of halide ions and increase with increasing potentials. From the frequency, the rate of AgNP oxidation as compared with the timescale the AgNP is in electrical contact with the electrode can be inferred, and hence is indicative of the relative kinetics of the oxidation process. Primarily based on these results, we propose the initial formation of the silver (I) nucleus (Ag+, AgCl, AgBr or AgI) as the rate-determining process of silver oxidation on the nanoparticle. [ABSTRACT FROM AUTHOR]

Potassium (de-)insertion from Prussian blue (PB) is investigated at the single and multi-particle scale. The electrochemical behaviour is found to differ between the two measurement types. At the single particle level, oxidation of the PB nanoparticles with concomitant K+ deinsertion occurs more readily than the associated reduction, relating to K+ insertion. In contrast, the cyclic voltammetry of PB in a composite electrode containing conductive additives and polymeric binder suggests the opposite behaviour. Implications for assessing battery materials are discussed. [ABSTRACT FROM AUTHOR]

Fluorescence microscopy and electrochemistry were employed to examine capping agent dynamics in silver nanoparticles capped with DNA intercalated with ethidium bromide, a fluorescent molecule. The capped NPs were studied first electrochemically, demonstrating that the intercalation of the capping agent promotes oxidation of the silver core, occurring at 0.50 V (vs. Ag, compared with 1.15 V for Ag NPs capped in DNA alone). Second, fluorescence electrochemical microscopy revealed that the electron transfer from the nanoparticles is gated by the capping agent, allowing dynamic insights unobservable using electrochemistry alone. [ABSTRACT FROM AUTHOR]

Particle-impact electrochemistry is employed to study spherical polyethylene microparticles suspended in an aqueous solution. This electrochemical method detects polyethylene microparticles impacting on a carbon fiber electrode generating a transient current response or 'spike'. We interpret the physio-chemical origin of the spikes and accurately identify particle size distributions and concentrations for microparticles of sizes 1-10 μm. [ABSTRACT FROM AUTHOR]

Hydroxylated rhodamines, carbopyronines, silico- and germanorhodamines with absorption maxima in the range of 530-640 nm were prepared and applied in specific labeling of living cells. The direct and high-yielding entry to germa- and silaxanthones tolerates the presence of protected heteroatoms and may be considered for the syntheses of various sila- and germafluoresceins, as well as -rhodols. Application in stimulated emission depletion (STED) fluorescence microscopy revealed a resolution of 50-75 nm in one- and two-color imaging of vimentin-HaloTag fused protein and native tubulin. The established structure-property relationships allow for prediction of the spectral properties and the positions of spirolactone/zwitterion equilibria for the new analogues of rhodamines, carbo-, silico-, and germanorhodamines using simple additive schemes. [ABSTRACT FROM AUTHOR]

Coronal mass ejections (CMEs), a kind of energetic solar eruptions, are an integral subject of space weather research. Numerical magnetohydrodynamic (MHD) modeling, which requires powerful computational resources, is one of the primary means of studying the phenomenon. With increasing accessibility of such resources, grows the demand for user-friendly tools that would facilitate the process of simulating CMEs for scientific and operational purposes. The Eruptive Event Generator based on Gibson-Low flux rope (EEGGL), a new publicly available computational model presented in this paper, is an effort to meet this demand. EEGGL allows one to compute the parameters of a model flux rope driving a CME via an intuitive graphical user interface. We provide a brief overview of the physical principles behind EEGGL and its functionality. Ways toward future improvements of the tool are outlined. [ABSTRACT FROM AUTHOR]

Oxidative addition of N-aminophthalimide to 1,2,4-triaryl-1-azabuta-1,3-dienes leads, in most cases, to the regio-defined formation of 1,3,5-triarylpyrazoles in moderate to good yields through [4+1] annulation. This transformation is supposed to proceed by nitrenoid attack onto a lone pair of electrons of the imine nitrogen atom to give the vinylazomethine imine, followed by its 1,5-electrocyclization into pyrazoline and further aromatization into pyrazole. Rare examples of 2-imidoyl-1-phthalimidoaziridines that are formed by competitive [2+1] cycloaddition onto the C=C bond were isolated in low yields for 1-azadienes with electron-deficient aryl substituents at the imine nitrogen atom. [ABSTRACT FROM AUTHOR]

The specific apparent capacitance (Farads per unit geometric area) of commercial carbon microdisc electrodes and in-house fabricated carbon microcylinders is studied through the use of cyclic voltammetry. Home-made microcylinder electrodes exhibit lower specific apparent capacitances and as a result facilitate lower limits of detection. We further demonstrate practically how the electroanalytical limit of the detection of solution phase trace oxygen is significantly improved using such microcylinder electrodes. Finally we show that after the degassing of a solution by nitrogen purging even in the most commonly encountered 'best' case scenarios approximately tens of μM of oxygen remain present in the electrochemical cell, unobservable by the commercial microdisc electrodes, but detectable with microcylinder electrodes, testifying to their analytical superiority. [ABSTRACT FROM AUTHOR]

Cyclic voltammetry is used to investigate the oxidation of chloride on platinum nanoparticles. The electrochemical response of the nanoparticles drop-cast onto a glassy carbon electrode is compared to that recorded at a platinum macroelectrode. The use of 'nano'- and 'macro'-scale Pt reveals different ratios of the electrochemically formed products, chlorine (Cl2) and the trichloride (Cl3−) anion. This difference in the speciation is attributed to the chloride oxidation being a surface-reaction-limited process. For the situation in which there are a limited number of active sites available on the electrode, owing to low nanoparticle surface coverages, the sub-diffusion-limited currents result in higher chloride concentrations adjacent to the electrochemical interface. This excess chloride at the interface leads to the formation of the trichloride anion. The effect of surface oxide formation towards the chloride oxidation is also examined on both electrodes. Formation of platinum oxide serves to inhibit the rate of chloride oxidation. [ABSTRACT FROM AUTHOR]

We demonstrate that the concentration of a red blood cell solution under physiological conditions can be determined by electrochemical voltammetry. The magnitude of the oxygen reduction currents produced at an edge-plane pyrolytic graphite electrode was diagnosed analytically at concentrations suitable for a point-of-care test device. The currents could be further enhanced when the solution of red blood cells was exposed to hydrogen peroxide. We show that the enhanced signal can be used to detect red blood cells at a single entity level. The method presented relies on the catalytic activity of red blood cells towards hydrogen peroxide and on surface-induced haemolysis. Each single cell activity is expressed as current spikes decaying within a few seconds back to the background current. The frequency of such current spikes is proportional to the concentration of cells in solution. [ABSTRACT FROM AUTHOR]

We report the voltammetry of alloy nanoparticles by using cyclic voltammetry to study gold-silver alloy nanoparticles. Through careful comparison with the response of pure gold nanoparticles, pure silver nanoparticles, and their mixture, the contrasting electrochemical behavior of the alloy nanoparticles is established, providing insights into the electrochemical stability of gold-silver alloy nanoparticles in chloride-containing media. [ABSTRACT FROM AUTHOR]

Colloidal suspensions of Bi2O3 nanoparticles were studied in aqueous solution using imaging and electrochemical techniques. Nanoparticle tracking analysis revealed the particles to be agglomerated. In contrast, electrochemical detection via the nano-impacts technique showed almost exclusive detection of monomeric nanoparticles. Comparison of the two techniques allows the conclusion to be drawn that the agglomeration/deagglomeration of the nanoparticles is reversible. A minimum rate constant for the deagglomeration process was estimated. [ABSTRACT FROM AUTHOR]

The field of nanoparticle (NP) sizing encompasses a wide array of techniques, with electron microscopy and dynamic light scattering (DLS) having become the established methods for NP quantification; however, these techniques are not always applicable. A new and rapidly developing method that addresses the limitations of these techniques is the electrochemical detection of NPs in solution. The 'nano-impacts' technique is an excellent and qualitative in situ method for nanoparticle characterization. Two complementary studies on silver and silver bromide nanoparticles (NPs) were used to assess the large radius limit of the nano-impact method for NP sizing. Noting that by definition a NP cannot be larger than 100 nm in diameter, we have shown that the method quantitatively sizes at the largest limit, the lower limit having been previously reported as ∼6 nm. [ABSTRACT FROM AUTHOR]

Significant effort has been devoted to developing effective cancer vaccines based on dendritic cells (DCs) loaded with various tumour antigens, including DNA constructs that carry sequences of tumour-associated antigens (TAAs). Such vaccines efficiently and selectively activate the T cell immune response. In this study, we describe a method to induce an antitumour immune response in mononuclear cell (MNC) cultures from colorectal cancer patients using DNA-transfected DCs encoding TAA epitopes of carcinoembryonic antigen, epithelial cell adhesion molecule and mucin 4. DCs were obtained from peripheral blood monocytes of colorectal cancer patients. Magnetic-assisted transfection was used to deliver the genetic constructs to DCs. To assess the potency of the immune response, the antitumour cytotoxic response was assessed by lymphocyte intracellular perforin and the MNC cytotoxic activity against autologous tumour cells. We showed that polyepitope DNA-transfected DCs enhanced MNC antitumour activity, increasing tumour cell death and the percentage of perforin-positive lymphocytes. In addition, DNA-transfected DCs elicited a cytotoxic response that was as efficient as that of tumour lysate-loaded DCs. Taken together, the data suggest that it is feasible to induce an antitumour immune response in colorectal MNCs using transfected DCs. Thus, the DNA construct reported in this study may potentially be used in therapeutic and prophylactic DC-based vaccines. [ABSTRACT FROM AUTHOR]

The geometry of quasi-spherical nanoparticles is investigated. The combination of SEM imaging and electrochemical nano-impact experiments is demonstrated to allow sizing and characterization of the geometry of single silver nanoparticles. [ABSTRACT FROM AUTHOR]

A new approach to benzo-annelated δ-sultams containing an aryl-nitrogen bond is described. The method, which involves the intramolecular Michael cyclization of tert-butyl ortho-[ N-(methoxycarbonylmethyl)sulfonylamino]cinnamates, allows the synthesis of secondary sultams as well as their tertiary analogues and bridged tricyclic derivatives efficiently and diastereoselectively. [ABSTRACT FROM AUTHOR]

A wide range of five- and six-membered sultams bearing an α-ethoxycarbonyl-α-methyl substituent or an α-aryl group (17 examples) were synthesized by the cyclodialkylation of α-substituted methanesulfonanilides with α,ω-dihaloalkanes in the presence of K2CO3 or under phase-transfer catalysis (PTC) conditions. Upon treatment with K2CO3 in N, N-dimethylformamide (DMF) or NaH in dimethyl sulfoxide (DMSO), N-(2,3-dibromopropyl)-α-toluenesulfonanilides furnished different 1,3-diaryl-2-thia-3-azabicyclo[3.1.0]hexane 2,2-dioxides in good to excellent yields (51-88 %, 16 examples). The 4-methoxyphenyl (PMP) group was easily removed from the sultam nitrogen atom by treatment of the corresponding bicyclic sultams with cerium(IV) ammonium nitrate in acetonitrile (71-84 % yield, 6 examples). [ABSTRACT FROM AUTHOR]

Systematic studies of reaction of nitronium with substituted benzenes (Alk‐, X‐Ph‐, CH3O‐, Cl‐, ‐COOCH3, ‐NO2, and other) were performed using semiempirical methods Austin model 1 and Solvation model v. 2.1 (SM2.1). Reaction path and maps of potential energy surface were investigated, including charge and thermodynamic properties of transition states and intermediate σ‐complexes. Main factors of reactivity—deformation energy and orbital and coulomb interaction—were considered by means of energy partitioning procedure, theory of Perturbation of Molecular Orbitals (PMO), etc. Firm correlation between calculated activation barriers and enthalpies of σ‐complex formation was found. It was found that the above‐mentioned factors successfully joined in enthalpy of protonation of aromatic substrates; thus, this parameter appeared to be ideal index of reactivity of arenes in nitration reaction. Coulomb interaction of nitronium and substituent in transition states explained cases of abnormally high reactivity of ortho position (e.g., in substituted biphenyls). © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004 [ABSTRACT FROM AUTHOR]