524 research outputs found

    Optical evidence for a magnetically driven structural transition in the spin web Cu3TeO6Cu_3TeO_6

    Full text link
    Cu3TeO6Cu_3TeO_6 is a modest frustrated S=1/2S=1/2 spin system, which undergoes an anti-ferromagnetic transition at TN61T_N\sim61 KK. The anti-ferromagnetic spin alignment in Cu3TeO6Cu_3TeO_6 below TNT_N is supposed to induce a magneto-elastic strain of the lattice. The complete absorption spectrum of Cu3TeO6Cu_3TeO_6 is obtained through Kramers-Kronig transformation of the optical reflectivity, measured from the far-infrared up to the ultraviolet spectral range as a function of temperature (TT). Below T50T^*\sim 50 KK, we find a new mode at 208 cm1cm^{-1}. The spectral weight associated to this additional mode increases as (TT)1/2\propto (T^*-T)^{1/2} with decreasing TT below TT^*. The implication of the optical findings will be discussed in relation to the magnetic phase transition at TNT_N.Comment: 9 pages, 3 figure

    Giant phonon anomalies in the pseudo-gap phase of TiOCl

    Full text link
    We report infrared and Raman spectroscopy results of the spin-1/2 quantum magnet TiOCl. Giant anomalies are found in the temperature dependence of the phonon spectrum, which hint to unusual coupling of the electronic degrees of freedom to the lattice. These anomalies develop over a broad temperature interval, suggesting the presence of an extended fluctuation regime. This defines a pseudo-gap phase, characterized by a local spin-gap. Below 100 K a dimensionality cross-over leads to a dimerized ground state with a global spin-gap of about 2Δspin\Delta_{spin}\approx~430 K.Comment: 4 pages, 3 figures, for further information see http://www.peter-lemmens.d

    Optical evidence for the proximity to a spin-density-wave metallic state in Na0.7_{0.7}CoO2_2

    Full text link
    We present the optical properties of \na single crystals, measured over a broad spectral range as a function of temperature (TT). The capability to cover the energy range from the far-infrared up to the ultraviolet allows us to perform reliable Kramers-Kronig transformation, in order to obtain the absorption spectrum (i.e., the complex optical conductivity). To the complex optical conductivity we apply the generalized Drude model, extracting the frequency dependence of the scattering rate (Γ\Gamma) and effective mass (mm^*) of the itinerant charge carriers. We find that Γ(ω)ω\Gamma(\omega)\sim \omega at low temperatures and for ω>T\omega > T. This suggests that \na is at the verge of a spin-density-wave metallic phase

    Optical evidence for a spin-filter effect in the charge transport of Eu0.6Ca0.4B6Eu_{0.6}Ca_{0.4}B_{6}

    Full text link
    We have measured the optical reflectivity R(ω)R(\omega) of Eu0.6Ca0.4B6Eu_{0.6}Ca_{0.4}B_{6} as a function of temperature between 1.5 and 300 KK and in external magnetic fields up to 7 TT. The slope at the onset of the plasma edge feature in R(ω)R(\omega) increases with decreasing temperature and increasing field but the plasma edge itself does not exhibit the remarkable blue shift that is observed in the binary compound EuB6EuB_{6}. The analysis of the magnetic field dependence of the low temperature optical conductivity spectrum confirms the previously observed exponential decrease of the electrical resistivity upon increasing, field-induced bulk magnetization at constant temperature. In addition, the individual exponential magnetization dependences of the plasma frequency and scattering rate are extracted from the optical data.Comment: submitted to Phys. Rev. Let

    The antibody-drug conjugate loncastuximab tesirine for the treatment of diffuse large B-cell lymphoma

    Get PDF
    Diffuse large B-cell lymphoma (DLBCL) is a heterogenous subtype of non-Hodgkin lymphoma. Relapsed/refractory disease represents remains an unmet medical need, despite the introduction of novel cellular and targeted therapies. Loncastuximab tesirine is a cluster of differentiation19-targeting antibody-drug conjugate approved by the US Food and Drug Administration for relapsed DLBCL after 2 lines of systemic therapy based on a trial showing a 48.3% overall response rate. The spectrum of its clinical applications is expanding and is now being tested in other B-cell malignancies

    Evaluation of carcass and meat traits of Muscovy duck fed with black soldier fly partially defatted meal

    Get PDF
    The aim of this study was to evaluate the carcass characteristics and breast meat quality in Muscovy duck (Cairina moschata domestica) fed different inclusion levels of a partially defatted black soldier fly larva (BSF) meal. A total of 256 Muscovy ducklings (average live weight, LW: 71.32\ub12.70 g) were reared from day 3 to day 48 and randomly allotted in 32 pens (8 replicates/treatment). Four different diets were formulated with increasing substitution level of corn gluten meal with BSF larva meal (0, 3, 6 and 9%; BSF0, BSF3, BSF6 and BSF9, respectively) and divided in 3 feeding phases: starter (1-14 days), grower (14-35 days) and finisher (35-48 days). At day 48, 2 animals/replicate were slaughtered and dissected to determine their carcass yields. The weights of spleen, bursa of Fabricius, liver, heart and abdominal fat were recorded. Breast and thigh muscles were then excised from 16 ducks/treatment and weighted. Ultimate pH (pHu) and L*, a*, b* colour values were then measured on breast muscle. The collected data were tested by means of oneway ANOVA evaluating the effect of dietary BSF inclusion level by polynomial contrasts. Significance was declared at P<0.05. The inclusion of BSF did not affect final LW (2,515.68\ub192.42 g on average). Hot and cold carcass weights showed a quadratic response (P<0.05) to increasing BSF larva meal, with a minimum corresponding to BSF6; however, refrigeration losses were not affected by treatments. Weight of spleen, bursa of Fabricius, liver and heart did not differ among treatments. The weight of abdominal fat showed a quadratic response to increasing BSF meal with a minimum corresponding to BSF6 group (P<0.05). Breast and thigh yields, pHu and L*, a*, b* colour values did not differ among groups. With the exception of BSF6, the inclusion of BSF meal did not affect meat traits and carcass characteristics, confirming the potential use of BSF meal in Muscovy duck diets

    Magneto-optical evidence of double exchange in a percolating lattice

    Full text link
    Substituting EuEu by CaCa in ferromagnetic EuB6EuB_6 leads to a percolation limited magnetic ordering. We present and discuss magneto-optical data of the Eu1xCaxB6Eu_{1-x}Ca_{x}B_6 series, based on measurements of the reflectivity R(ω)R(\omega) from the far infrared up to the ultraviolet, as a function of temperature and magnetic field. Via the Kramers-Kronig transformation of R(ω)R(\omega) we extract the complete absorption spectra of samples with different values of xx. The change of the spectral weight in the Drude component by increasing the magnetic field agrees with a scenario based on the double exchange model, and suggests a crossover from a ferromagnetic metal to a ferromagnetic Anderson insulator upon increasing CaCa-content at low temperatures.Comment: 10 pages, 3 figure

    Apparent digestibility of insect protein meals for rainbow trout

    Get PDF
    Insect meals are considered to be promising future ingredients for aquaculture feeds. In past feeding trials in rainbow trout, insect meals were included in diets only on the basis of their nutrients content and energy density without taking into account their biological availability due to the lack of their digestible values. Apparent digestibility (ADC) provides good indication of the bioavailability of nutrients and energy thus providing rational basis for the correct inclusion of feedstuffs. The aim of this research was to assess, in an in vivo trial on rainbow trout, the ADC of five full fat insect meals: one Tenebrio molitor (TM), two Hermetia illucens obtained through two different process (HI1 and HI2), one Musca domestica (MD), and one Alphitobius diaperinus (AD). Fish were fed a high-quality reference diet (R) and test diets obtained mixing the R diet with each of the test ingredients at a ratio of 70:30. Diets contained 1% celite as inert marker. Fish were fed to visual satiety twice a day and faecal samples collected using a continuous automatic device. Faeces were freeze dried and frozen (-20 \ub0C) until analyses. The ADC of dry matter, crude protein and ether extract of each insect meal diet were calculated. ADC for dry matter varied between 70.07 (HI1) and 80.85 (TM). ADC for protein was above 84% in all treatments and resulted the highest in MD, TM and AD treatments. Ether extract apparent digestibility significantly differed among diets with the highest value reported for TM treatment. All treatments reported values higher than 96%. Observed differences could be due to the insect species and meal treatment but in general, tested insect meals were highly digestible for rainbow trout. The results from this research could be useful to optimize the diet formulation

    Occupational Exposure to Metal Engineered Nanoparticles: A Human Biomonitoring Pilot Study Involving Italian Nanomaterial Workers

    Get PDF
    Advances in nanotechnology have led to an increased use of engineered nanoparticles (ENPs) and the likelihood for occupational exposures. However, how to assess such exposure remains a challenge. In this study, a methodology for human biomonitoring, based on Single Particle Inductively Coupled Plasma Mass Spectrometry (SP-ICP-MS), was developed as a tool to assess the ENPs exposure of workers involved in nanomaterial activities in two Italian Companies. The method was validated for size and number concentration determination of Ag, Au, In2O3, Ir, Pd, Pt, and TiO2 NPs in urine and blood samples. The results showed the presence of In2O3 NPs in blood of exposed workers (mean, 38 nm and 10,371 particles/mL), but not in blood of controls. Silver, Au, and TiO2 NPs were found in urine (mean, Ag 29 nm and 16,568 particles/mL) or blood (mean, Au 15 nm and 126,635 particles/mL; TiO2 84 nm and 27,705 particles/mL) of workers, though these NPs were found also in controls. The presence of ENPs in both workers and controls suggested that the extra-professional exposure is a source of ENPs that cannot be disregarded. Iridium, Pd, and Pt NPs were not detected neither in blood nor in urine. Overall, the findings provided a rational basis to evaluate the exposure assessment to ENPs in cohorts of workers as part of risk assessment and risk management processes in workplaces

    Magneto-optical Kerr effect in Eu1xCaxB6Eu_{1-x}Ca_{x}B_{6}

    Full text link
    We have measured the magneto-optical Kerr rotation of ferromagnetic Eu1xCaxB6Eu_{1-x}Ca_{x}B_{6} with x=0.2 and 0.4, as well as of YbB6YbB_{6} serving as the non-magnetic reference material. As previously for EuB6EuB_{6}, we could identify a feature at 1 eVeV in the Kerr response which is related with electronic transitions involving the localized 4f electron states. The absence of this feature in the data for YbB6YbB_{6} confirms the relevance of the partially occupied 4f states in shaping the magneto-optical features of EuEu-based hexaborides. Disorder by CaCa-doping broadens the itinerant charge carrier contribution to the magneto-optical spectra
    corecore