Proton emission in α-induced reactions at 43 MeVnucleon

Inclusive proton spectra and proton-proton correlations have been measured from α + ⁵⁸Ni and α + ¹⁹⁷Au reactions at energies E_α = 100 MeV and 172 MeV. The inclusive spectra are compared to results of a simple model assuming local equilibration of the energy transferred to the target nucleons. This model describes the energy and angular dependence sufficiently well at angles ? 40°. Due to finite number effects, it also explains the occurrence of differences between in-plane to out-of-plane pp correlations. In addition, the measured coincidences indicate contributions from quasifree pp scattering.     

One-step synthesis and functionalization of hydroxyl-decorated magnetite nanoparticles

Magnetite nanoparticles covered by a layer of omega-hydroxycarboxylic acid were synthesized in one step by high-temperature decomposition of iron(III) omega-hydroxycarboxylates in tri- and tetra-ethylene glycol. The nanoparticles were characterized by TEM, XRD, IR, XPS and NMR techniques in order to show that they comprise a crystalline magnetite core and actually bear on the outer surface terminal hydroxy groups. The latter ones are convenient "handles" for further functionalization as opposed to the chemically-inert aliphatic chains which cover conventionally synthesized nanoparticles. This was shown by several examples in which the hydroxy groups on the nanoparticle surface were easily transformed in other functional groups or reacted with other molecules. For instance, the hydroxyl-decorated nanoparticles were made water soluble by esterification with a PEGylated acetic acid. The reactive behavior of the surfactant monolayer was monitored by degrading the nanoparticles with aqueous acid and isolating the surfactant for NMR characterization. In general, the reactivity of the terminal hydroxyl groups on the nanoparticle surface parallels that observed in the free surfactants. The reported hydroxyl-decorated magnetite nanoparticles can be thus considered as pro-functional nanoparticles, i.e., a convenient starting material to functionalized magnetic nanoparticles.     

Development of an Injectable Calcium Phosphate/Hyaluronic Acid Microparticles System for Platelet Lysate Sustained Delivery Aiming Bone Regeneration

Despite the biocompatibility and osteoinductive properties of calcium phosphate (CaP) cements their low biodegradability hampers full bone regeneration. Herein the incorporation of CaP cement with hyaluronic acid (HAc) microparticles loaded with platelet lysate (PL) to improve the degradability and biological performance of the cements is proposed. Cement formulations incorporating increasing weight ratios of either empty HAc microparticles or microparticles loaded with PL (10 and 20 wt%) are developed as well as cements directly incorporating PL. The direct incorporation of PL improves the mechanical properties of the plain cement, reaching values similar to native bone. Morphological analysis shows homogeneous particle distribution and high interconnectivity between the HAc microparticles. The cements incorporating PL (with or without the HAc microparticles) present a sustained release of PL proteins for up to 8 d. The sustained release of PL modulates the expression of osteogenic markers in seeded human adipose tissue derived stem cells, thus suggesting the stimulatory role of this hybrid system toward osteogenic commitment and bone regeneration applications.

     

General phase transition models for vehicular traffic with point constraints on the flow

In this paper, we present a general phase transition model that describes the evolution of vehicular traffic along a one‐lane road. Two different phases are taken into account, according to whether the traffic is low or heavy. The model is given by a scalar conservation law in the free‐flow phase and by a system of 2 conservation laws in the congested phase. The free‐flow phase is described by a one‐dimensional fundamental diagram corresponding to a Newell‐Daganzo type flux. The congestion phase is described by a two‐dimensional fundamental diagram obtained by perturbing a general fundamental flux. In particular, we study the resulting Riemann problems in the case a local point constraint on the flow of the solutions is enforced.     

Study of Be + C elastic scattering at energies near the Coulomb barrier

In this work, angular distribution measurements for the elastic channel were performed for the ⁹Be + ¹²C reaction at the energies ELab=13.0$E_{\mathit{Lab}}=13.0$, 14.5, 17.3, 19.0 and 21.0 MeV, near the Coulomb barrier. The data have been analyzed in the framework of the double folding São Paulo potential. The experimental elastic scattering angular distributions were well described by the optical potential at forward angles for all measured energies. However, for the three highest energies, an enhancement was observed for intermediate and backward angles. This can be explained by the elastic transfer mechanism.     

High performance liquid chromatography-high resolution mass spectrometry and micropulverized extraction for the quantification of amphetamines, cocaine, opioids, benzodiazepines, antidepressants and hallucinogens in 2.5 mg hair samples

A high performance liquid chromatography-high resolution mass spectrometry (HPLC-HRMS) method for simultaneous screening and quantification of 28 drugs was developed and validated for 2.5 mg hair samples. Target drugs and their metabolites included amphetamines, cocaine, opioids, benzodiazepines, antidepressants, and hallucinogens. After decontamination, hair samples were extracted with 200 μL of a mixture of water: acetonitrile:1 M trifluoroacetic acid (80:10:10, v/v) using a 5 min simultaneous pulverization/extraction step. The extracts were analysed by HPLC-HRMS in an Orbitrap at a nominal resolution of 60,000, with concomitant in source collisional experiments (in source CID). Gradient elution on an Atlantis T3 column resolved 28 target compounds and 5 internal standards. Total chromatographic run time was 26 min. Calibration was achieved by linear regression analysis utilizing six calibration points; R2 ranged from 0.9964 to 0.9999, the limits of quantification were 0.1 ng/mg for 8 compounds, 0.2 ng/mg for 16 compounds and 0.5 ng/mg for 4 compounds; mean relative errors from -21% to +23% were obtained; relative standard deviation, used to estimate repeatability and intermediate reproducibility at three concentrations, was always less than 20%. Process efficiency and recoveries for all analytes were better than 65 and 73%, respectively, at any concentration. The method was applied to hair samples from forensic investigations that contained a broad assortment of drugs of abuse and pharmaceuticals. The use of concomitant HRMS full scan and CID afforded the possibility of retrospective analysis for discovering untargeted drugs.     

Changes in amniotic fluid and umbilical cord serum proteomic profiles of foetuses with intrauterine growth retardation

Foetal growth is a result of a complex net of processes, requiring coordination within the maternal, placental, and foetal compartments, the imbalance or lack of which may lead to intrauterine growth restriction (IUGR). IUGR is the major cause of perinatal morbidity and mortality, and is also related to enhanced morbidity and metabolic abnormalities later in life. In the present study, the protein profiles of umbilical cord serum (UCS) and amniotic fluid (AF) of ten IUGR and ten appropriate for gestational age newborns have been analysed by 2-DE, and nanoHPLC-Chip/MS technology. A total of 18 and 13 spots were found to be differentially expressed (p<0.01) in UCS and AF respectively. The unique differentially expressed proteins identified by MS/MS analysis were 14 in UCS, and 11 in AF samples. Protein gene ontology classification indicate that 21% of proteins are involved in inflammatory response, 20% in immune response, while a smaller proportion are related to transport, blood pressure, and coagulation. These results support the conclusion that the IUGR condition alters the expression of proteins involved in the coagulation process, immune mechanisms, blood pressure and iron and copper homeostasis control, offering a new insight into IUGR pathogenesis.     

A Rheumatoid arthritis study using Raman spectroscopy

Rheumatoid arthritis (RA) is characterized by chronic inflammation of the joints and can lead to a progressive destruction of articular cartilage and bone. In this study, the specificity and sensitivity of the RA diagnostic methods based on the receiver-operating characteristic curves for monitoring C-reactive protein (CRP) and rheumatoid factor (RF) were compared with the Raman spectroscopic diagnostic method developed in this work. Sera from 24 patients with rheumatoid arthritis and from 16 healthy individuals were analyzed to assess the biochemical composition and presence of inflammatory activity by the aforementioned methods. By comparing with the clinical results for specificity and sensitivity from the RF and CRP tests, we show that the overall results from the newly developed Raman method were significantly better, with a specificity of 96%, a sensitivity of 88%, and correctly identifying 92% of the RA and healthy individuals, while the RF test gave a specificity of 100% and a sensitivity of 54%, and the CRP test gave a specificity of 87% and a sensitivity of 58%, respectively.     

Synthesis and physico-chemical characterization of Au/TiO2 nanostructures formed by novel “cold” and “hot” nanosoldering of Au and TiO2 nanoparticles dispersed in water

A novel approach to synthesize Au/TiO₂ nanostructures with interesting optical properties is presented and discussed. It is based on the nanoparticle “cold” or “hot” nanosoldering occurring when two water suspensions of Au and TiO₂ nanoparticles are merely mixed at room temperature or laser irradiated after mixing.Thanks to the high fraction and mutual reactivity of surface species, immediately after the mixing process, the encounters between Au and TiO₂ nanoparticles in liquid phase are enough for “cold” nanosoldering of gold nanoparticles onto TiO₂ nanoparticles to occur. The optical characterizations show that this fast process (timescale less than 1 min) is followed by a slower process, attributable to some change of the Au nanoparticles. This latter process is significantly accelerated by the 532 nm laser light illumination. The structural and optical properties of “cold” and “hot” nanosoldered Au-TiO₂ nanoparticles were investigated by TEM, UV-vis and fluorescence spectroscopies.Interesting optical limiting response was detected at laser fluences above 0.8 J/cm². The nature of the nonlinear effect was investigated by the Z-scan technique, determining both the nonlinear absorption coefficient and the refraction index. Such interesting non-linear optical properties are worth to be tailored for specific applications.     

Ultrasound-assisted pullulan/montmorillonite bionanocomposite coating with high oxygen barrier properties

In this paper, the preparation and characterization of oxygen barrier pullulan sodium montmorillonite (Na(+)-MMT) nanocomposite coatings are presented for the first time. Full exfoliation of platelets during preparation of the coating water dispersions was mediated by ultrasonic treatment, which turned out to be a pivotal factor in the oxygen barrier performance of the final material even at high relative humidity (RH) conditions [oxygen permeability coefficients ~1.43 ± 0.39 and 258.05 ± 13.78 mL·μm·m(-2)·(24 h)(-1)·atm(-1) at 23 °C and 0% RH and 70% RH, respectively]. At the micro- and nanoscale, the reasons are discussed. The final morphology of the coatings revealed that clay lamellae were stacked on top of one another, probably due to the forced confinement of the platelets within the coating thickness after solvent evaporation. This was also confirmed by modeling the experimental oxygen permeability data with the well-known Nielsen and Cussler permeation theoretical models, which suggested a reasonable aspect ratio (α) of ~100. Electron microscopic analyses also disclosed a peculiar cell-like arrangement of the platelets. The stacking of the clay lamellae and the cell-like arrangement create the excellent oxygen barrier properties. Finally, we demonstrated that the slight haze increase in the bionanocomposite coating materials arising from the addition of the clays depends on the clay concentration but not so much on the sonication time, due to the balance of opposite effects after sonication (an increase in the number of scattering centers but a reduction in their size).