210 research outputs found

    Prediction of Drug Loading in the Gelatin Matrix Using Computational Methods

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    The delivery of drugs is a topic of intense research activity in both academia and industry with potential for positive economic, health, and societal impacts. The selection of the appropriate formulation (carrier and drug) with optimal delivery is a challenge investigated by researchers in academia and industry, in which millions of dollars are invested annually. Experiments involving different carriers and determination of their capacity for drug loading are very time-consuming and therefore expensive; consequently, approaches that employ computational/theoretical chemistry to speed have the potential to make hugely beneficial economic, environmental, and health impacts through savings in costs associated with chemicals (and their safe disposal) and time. Here, we report the use of computational tools (data mining of the available literature, principal component analysis, hierarchical clustering analysis, partial least squares regression, autocovariance calculations, molecular dynamics simulations, and molecular docking) to successfully predict drug loading into model drug delivery systems (gelatin nanospheres). We believe that this methodology has the potential to lead to significant change in drug formulation studies across the world

    Quantum non-demolition (QND) modulation of quantum interference

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    We propose an experiment where quantum interference between two different paths is modulated by means of a QND measurement on one or both the arm of the interferometer. The QND measurement is achieved in a Kerr cell. We illustrate a scheme for the realisation of this experiment and some further developments.Comment: accepted for publicatio

    Physical properties of FeSe0.5_{0.5}Te0.5_{0.5} single crystals grown under different conditions

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    We report on structural, magnetic, conductivity, and thermodynamic studies of FeSe0.5_{0.5}Te0.5_{0.5} single crystals grown by self-flux and Bridgman methods. The samples were prepared from starting materials of different purity at various temperatures and cooling rates. The lowest values of the susceptibility in the normal state, the highest transition temperature TcT_c of 14.5 K, and the largest heat-capacity anomaly at TcT_c were obtained for pure (oxygen-free) samples. The critical current density jcj_c of 8×1048 \times 10^4 A/cm2^2 (at 2 K) achieved in pure samples is attributed to intrinsic inhomogeneity due to disorder at the cation and anion sites. The impure samples show increased jcj_c up to 2.3×1052.3 \times 10^5 A/cm2^2 due to additional pinning centers of Fe3_3O4_4. The upper critical field Hc2H_{c2} of 500\sim 500 kOe is estimated from the resistivity study in magnetic fields parallel to the \emph{c}-axis. The anisotropy of the upper critical field γHc2=Hc2ab/Hc2c\gamma_{H_{c2}} = H_{_{c2}}^{ab}/H_{_{c2}}^{c} reaches a value 6\sim 6 at TTcT\longrightarrow T_c. Extremely low values of the residual Sommerfeld coefficient for pure samples indicate a high volume fraction of the superconducting phase (up to 97%). The electronic contribution to the specific heat in the superconducting state is well described within a single-band BCS model with a temperature dependent gap Δ0=27(1)\Delta_0 = 27(1) K. A broad cusp-like anomaly in the electronic specific heat of samples with suppressed bulk superconductivity is ascribed to a splitting of the ground state of the interstitial Fe2+^{2+} ions. This contribution is fully suppressed in the ordered state in samples with bulk superconductivity.Comment: 11 pages, 11 figures, 3 table

    Entangled-Photon Generation from Parametric Down-Conversion in Media with Inhomogeneous Nonlinearity

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    We develop and experimentally verify a theory of Type-II spontaneous parametric down-conversion (SPDC) in media with inhomogeneous distributions of second-order nonlinearity. As a special case, we explore interference effects from SPDC generated in a cascade of two bulk crystals separated by an air gap. The polarization quantum-interference pattern is found to vary strongly with the spacing between the two crystals. This is found to be a cooperative effect due to two mechanisms: the chromatic dispersion of the medium separating the crystals and spatiotemporal effects which arise from the inclusion of transverse wave vectors. These effects provide two concomitant avenues for controlling the quantum state generated in SPDC. We expect these results to be of interest for the development of quantum technologies and the generation of SPDC in periodically varying nonlinear materials.Comment: submitted to Physical Review

    Multi-gap superconductivity in a BaFe1.84Co0.16As2 film from optical measurements at terahertz frequencies

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    We measured the THz reflectance properties of a high quality epitaxial thin film of the Fe-based superconductor BaFe1.84_{1.84}Co0.16_{0.16}As2_2 with Tc_c=22.5 K. The film was grown by pulsed laser deposition on a DyScO3_3 substrate with an epitaxial SrTiO3_3 intermediate layer. The measured RS/RNR_S/R_N spectrum, i.e. the reflectivity ratio between the superconducting and normal state reflectance, provides clear evidence of a superconducting gap ΔA\Delta_A close to 15 cm1^{-1}. A detailed data analysis shows that a two-band, two-gap model is absolutely necessary to obtain a good description of the measured RS/RNR_S/R_N spectrum. The low-energy ΔA\Delta_A gap results to be well determined (ΔA\Delta_A=15.5±\pm0.5 cm1^{-1}), while the value of the high-energy gap ΔB\Delta_B is more uncertain (ΔB\Delta_B=55±\pm7 cm1^{-1}). Our results provide evidence of a nodeless isotropic double-gap scenario, with the presence of two optical gaps corresponding to 2Δ/kTc\Delta/kT_c values close to 2 and 7.Comment: Published Versio

    Hole-doping dependence of percolative phase separation in Pr_(0.5-delta)Ca_(0.2+delta)Sr_(0.3)MnO_(3) around half doping

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    We address the problem of the percolative phase separation in polycrystalline samples of Pr0.5δ_{0.5-\delta}Ca0.2+δ_{0.2+\delta}Sr0.3_{0.3}MnO3_3 for 0.04δ0.04-0.04\leq \delta \leq 0.04 (hole doping nn between 0.46 and 0.54). We perform measurements of X-ray diffraction, dc magnetization, ESR, and electrical resistivity. These samples show at TCT_C a paramagnetic (PM) to ferromagnetic (FM) transition, however, we found that for n>0.50n>0.50 there is a coexistence of both of these phases below TCT_C. On lowering TT below the charge-ordering (CO) temperature TCOT_{CO} all the samples exhibit a coexistence between the FM metallic and CO (antiferromagnetic) phases. In the whole TT range the FM phase fraction (XX) decreases with increasing nn. Furthermore, we show that only for n0.50n\leq 0.50 the metallic fraction is above the critical percolation threshold XC15.5X_C\simeq 15.5%. As a consequence, these samples show very different magnetoresistance properties. In addition, for n0.50n\leq 0.50 we observe a percolative metal-insulator transition at TMIT_{MI}, and for TMI<T<TCOT_{MI}<T<T_{CO} the insulating-like behavior generated by the enlargement of XX with increasing TT is well described by the percolation law ρ1=σ(XXC)t\rho ^{-1}=\sigma \sim (X-X_C)^t, where tt is a critical exponent. On the basis of the values obtained for this exponent we discuss different possible percolation mechanisms, and suggest that a more deep understanding of geometric and dimensionality effects is needed in phase separated manganites. We present a complete TT vs nn phase diagram showing the magnetic and electric properties of the studied compound around half doping.Comment: 9 text pages + 12 figures, submitted to Phys. Rev.

    usefulness of measurement of blood chromium levels in the assessment of occupational Cr(VI) exposure

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    Funding Information: This work has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author's organizations and/or Ministries. Luxembourg entered the study at a later stage and thus financed the study at its own means. Publisher Copyright: © 2022 The AuthorsOccupational exposures to hexavalent Chromium (Cr(VI)) can occur in welding, hot working stainless steel processing, chrome plating, spray painting and coating activities. Recently, within the human biomonitoring for Europe initiative (HBM4EU), a study was performed to assess the suitability of different biomarkers to assess the exposure to Cr(VI) in various job tasks. Blood-based biomarkers may prove useful when more specific information on systemic and intracellular bioavailability is necessary. To this aim, concentrations of Cr in red blood cells (RBC-Cr) and in plasma (P–Cr) were analyzed in 345 Cr(VI) exposed workers and 175 controls to understand how these biomarkers may be affected by variable levels of exposure and job procedures. Compared to controls, significantly higher RBC-Cr levels were observed in bath plating and paint application workers, but not in welders, while all the 3 groups had significantly greater P–Cr concentrations. RBC-Cr and P–Cr in chrome platers showed a high correlation with Cr(VI) in inhalable dust, outside respiratory protective equipment (RPE), while such correlation could not be determined in welders. In platers, the use of RPE had a significant impact on the relationship between blood biomarkers and Cr(VI) in inhalable and respirable dust. Low correlations between P–Cr and RBC-Cr may reflect a difference in kinetics. This study showed that Cr-blood-based biomarkers can provide information on how workplace exposure translates into systemic availability of Cr(III) (extracellular, P–Cr) and Cr(VI) (intracellular, RBC-Cr). Further studies are needed to fully appreciate their use in an occupational health and safety context.publishersversionpublishe

    HBM4EU chromates study - Usefulness of measurement of blood chromium levels in the assessment of occupational Cr(VI) exposure

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    Occupational exposures to hexavalent Chromium (Cr(VI)) can occur in welding, hot working stainless steel processing, chrome plating, spray painting and coating activities. Recently, within the human biomonitoring for Europe initiative (HBM4EU), a study was performed to assess the suitability of different biomarkers to assess the exposure to Cr(VI) in various job tasks. Blood-based biomarkers may prove useful when more specific information on systemic and intracellular bioavailability is necessary. To this aim, concentrations of Cr in red blood cells (RBC-Cr) and in plasma (P-Cr) were analyzed in 345 Cr(VI) exposed workers and 175 controls to understand how these biomarkers may be affected by variable levels of exposure and job procedures. Compared to controls, significantly higher RBC-Cr levels were observed in bath plating and paint application workers, but not in welders, while all the 3 groups had significantly greater P-Cr concentrations. RBC-Cr and P-Cr in chrome platers showed a high correlation with Cr(VI) in inhalable dust, outside respiratory protective equipment (RPE), while such correlation could not be determined in welders. In platers, the use of RPE had a significant impact on the relationship between blood biomarkers and Cr(VI) in inhalable and respirable dust. Low correlations between P-Cr and RBC-Cr may reflect a difference in kinetics. This study showed that Cr-blood-based biomarkers can provide information on how workplace exposure translates into systemic availability of Cr(III) (extracellular, P-Cr) and Cr(VI) (intracellular, RBC-Cr). Further studies are needed to fully appreciate their use in an occupational health and safety context.Highlights: - Suitability of blood biomarkers was evaluated to assess occupational Cr(VI)exposure; - Bath platers and painters had higher Red Blood Cells-Cr levels compared to controls; - Bath platers, painters and welders had higher plasma-Cr levels compared to controls; Red Blood Cells- and Plasma-Cr were highly correlated with inhalable Cr(VI) in platers; Blood-Cr biomarkers can provide information on systemic and intracellular availability.This work has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 733032 and received co-funding from the author’s organizations and/or Ministries. Luxembourg entered the study at a later stage and thus financed the study at its own means.info:eu-repo/semantics/publishedVersio

    Management of acute hypercortisolism

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    An occasional patient with Cushing's syndrome may require urgent management primarily because the chronic ravages of hypercortisolism have caused the patient to be in a precarious metabolic condition. The side effects of prolonged excess corticosteroids increase the risk of operations in such patients and must be considered in overall management. Among the many effects of hypercortisolism to be considered are hypertension, diabetes, ocular hypertension, myopathies, dermatologic changes including skin infection, pancreatitis, osteoporosis, pathological fractures, peptic ulcers, renal calculi, coagulopathies, hypokalemia, poor wound healing, and increased susceptibility to infection. The most effective way to avert these complications is by earlier diagnosis and definitive treatment of Cushing's syndrome. The present report includes a review of the etiology and diagnosis of Cushing's syndrome and the management of problems associated with hypercortisolism . Il est possible qu'un malade atteint de maladie de Cushing ait besoin d'être traité sans attente en raisons de troubles métaboliques sévères dus aux effets nocifs de l'hypercortisolisme chronique qui augmentent les risques opératoires et doivent être pris en considération avant tout traitement. Il en est ainsi de l'hypertension, du diabète, de l'hypertension intra-oculaire, des lésions dermiques comprenant l'infection cutanée, la pancréatite, l'ostéoporose, les fractures pathologiques, l'ulcère peptique, les calculs rénaux, les coagulopathies, l'hypokaliémie, la lenteur du processus de cicatrisation et l'augmentation de la suceptibilité à l'infection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41309/1/268_2005_Article_BF01655367.pd
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