1,218 research outputs found
Design, synthesis and biological activity of selective hCAs inhibitors based on 2-(benzylsulfinyl)benzoic acid scaffold
A large library of derivatives based on the scaffold of 2-(benzylsulfinyl)benzoic acid were synthesised and tested as atypical inhibitors against four different isoforms of human carbonic anhydrase (hCA I, II, IX and XII, EC 4.2.1.1). The exploration of the chemical space around the main functional groups led to the discovery of selective hCA IX inhibitors in the micromolar/nanomolar range, thus establishing robust structure-activity relationships within this versatile scaffold. HPLC separation of some selected chiral compounds and biological evaluation of the corresponding enantiomers was performed along with molecular modelling studies on the most active derivatives
Preferential expression of the transcription coactivator HTIF1alpha gene in acute myeloid leukemia and MDS-related AML
HTIF1α, a transcription coactivator which is able to mediate RARα activity and functionally interact with PML, is encoded by a gene on chromosome 7q32–34, which is a critical region in acute myeloid leukemias (AML). With the assumption that this gene may be related to AML, we investigated the HTIF1α DNA structure and RNA expression in leukemic cells from 36 M1–M5 AML patients (28 ‘de novo’ and eight ‘secondary’ to myelodysplastic syndrome (MDS)). Abnormal HTIF1α DNA fragments were never found, whereas loss of HTIF1α DNA was observed in the patients with chromosome 7q32 deletion and translocation, and in one case without detectable chromosome 7 abnormality. HTIF1α RNA was found in acute myelocytic leukemic blasts, and was almost undetectable in normal mononuclear cells. The expression varied among the patients: higher in M1 to M3 subtypes, with the highest values in M1; low levels were constantly observed in M4 and M5 AML. In addition, HTIF1α was significantly overexpressed in MDS-related AML (MDR-AML), but not in MDS. We also found that HTIF1α expression was high in myeloid cell lines. In myeloblastic HL60 and promyelocytic NB4 cells, induced to differentiate along the monocytic–macrophage pathway by TPA or vitamin D3, HTIF1α expression decreased, whereas it was maintained at high levels on induction to granulocytic differentiation by RA or DMSO. In K562 cells, HTIF1α RNA levels did not change after hemin-induced erythroid differentiation. These results suggest that HTIF1α could play a role in myeloid differentiation, being distinctly regulated in hematopoietic lineages
HST color-magnitude diagrams of 74 galactic globular clusters in the HST F439W and F555W bands
We present the complete photometric database and the color-magnitude diagrams
for 74 Galactic globular clusters observed with the HST/WFPC2 camera in the
F439W and F555W bands. A detailed discussion of the various reduction steps is
also presented, and of the procedures to transform instrumental magnitudes into
both the HST F439W and F555W flight system and the standard Johnson B and V
systems. We also describe the artificial star experiments which have been
performed to derive the star count completeness in all the relevant branches of
the color magnitude diagram. The entire photometric database and the
completeness function will be made available on the Web immediately after the
publication of the present paper.Comment: 21 pages, 77 figures. High resolution version of this paper can be
retrived at http://dipastro.pd.astro.it/globular
RubikAuth: Fast and Secure Authentication in Virtual Reality
There is a growing need for usable and secure authentication in virtual reality (VR). Established concepts (e.g., 2D graphical PINs) are vulnerable to observation attacks, and proposed alternatives are relatively slow. We present RubikAuth, a novel authentication scheme for VR where users authenticate quickly by selecting digits from a virtual 3Dcube that is manipulated with a handheld controller. We report two studies comparing how pointing using gaze, headpose, and controller tapping impacts RubikAuth’s usability and observation resistance under three realistic threat models. Entering a four-symbol RubikAuth password is fast:1.69 s to 3.5 s using controller tapping, 2.35 s to 4.68 s using head pose, and 2.39 s to 4.92 s using gaze and highly resilient to observations; 97.78% to 100% of observation attacks were unsuccessful. Our results suggest that providing attackers with support material contributes to more realistic security evaluations
Mineralogical characterization of fluorescent grossular garnet var. tsavorite from Merelani Hills, Tanzania
Tsavorite is the trade name for the green vanadium–chromium variety of grossular occurring in the Precambrian terrains in the areas of Merelani Hills (Tanzania) and Tsavo Park (Kenya) which are by far the most important source of gem grade specimens of tsavorite used for high jewellery. The tsavorite crystals from Merelani Hills exhibit a pink-red and yellow fluorescence when irradiated by common portable UV lamp, an unusual phenomenon among members of the garnet group. The electron density map calculated from the diffraction data and plotted against a grossular standard shows that an excess of negative charge is clearly pinpointed in the crystallographic site occupied by Al3+. The bulk elemental analysis shows that the most represented end-member, besides grossular, is the vanadium-bearing goldmanite garnet (3.82–4.08 mol %). The fluorometry with an excitation beam at 408 nm indicates a complex emission pattern with the most intense emissions at 701 and 716 nm and subordinately at 592 nm. The colour perception is dominated by the emission yellow band at 592 nm while the contribution of the red band modulates the colour ranging from bright orange to pink-red. The attribution of the emission at 592 nm is related to Mn2+ while the emissions at 701 and 716 nm could be related to the chromium content and/or to a possible fraction of vanadium as V2+. Because of the characteristic colour perceived under UV light, the use of a common led lamp can be useful as a diagnostic tool to easily identify tsavorite
Is Eriophyes mali Nalepa present in Italy?
In the last few years, blistering symptoms were observed on apple plants in commercial orchards. Blisters are commonly found on apple leaves as well as on small fruits. This symptom is compatible with that described for apple blister mites belonging to the genus Eriophyes (Eriophyidae). To assess the identity of the etiological agent, leaf blisters and buds of symptomatic apple and, as a control, pear plants were examined under the dissection microscope and eriophyoid mites were collected. Specimens were examined using both molecular and morphological approaches. The analysis of sequences confirmed that eriophyoid mites collected from symptomatic apple and pear plants are genetically different. Our analyses highlight a complex scenario inside the genus Eriophyes that is worth to be studied in more detai
Adhesive force distributions for tungsten dust deposited on bulk tungsten and beryllium-coated tungsten surfaces
Comprehensive measurements of the adhesive force for tungsten dust adhered to tungsten surfaces have been performed with the electrostatic detachment method. Monodisperse spherical dust has been deposited with gas dynamics techniques or with gravity mimicking adhesion as it naturally occurs in tokamaks. The adhesive force is confirmed to follow the log-normal distribution and empirical correlations are proposed for the size-dependence of its mean and standard deviation. Systematic differences are observed between the two deposition methods and attributed to plastic deformation during sticking impacts. The presence of thin beryllium coatings on tungsten surfaces is demonstrated to barely affect adhesion
Internal calibration of Gaia BP/RP low-resolution spectra
The full third Gaia data release will provide the calibrated spectra obtained
with the blue and red Gaia slit-less spectrophotometers. The main challenge
when facing Gaia spectral calibration is that no lamp spectra or flat fields
are available during the mission. Also, the significant size of the line spread
function with respect to the dispersion of the prisms produces alien photons
contaminating neighbouring positions of the spectra. This makes the calibration
special and different from standard approaches.
This work gives a detailed description of the internal calibration model to
obtain the spectrophotometric data in the Gaia catalogue. The main purpose of
the internal calibration is to bring all the epoch spectra onto a common flux
and pixel (pseudo-wavelength) scale, taking into account variations over the
focal plane and with time, producing a mean spectrum from all the observations
of the same source.
In order to describe all observations in a common mean flux and
pseudo-wavelength scale, we construct a suitable representation of the
internally calibrated mean spectra via basis functions and we describe the
transformation between non calibrated epoch spectra and calibrated mean spectra
via a discrete convolution, parametrising the convolution kernel to recover the
relevant coefficients.
The model proposed here is able to combine all observations into a mean
instrument to allow the comparison of different sources and observations
obtained with different instrumental conditions along the mission and the
generation of mean spectra from a number of observations of the same source.
The output of this model provides the internal mean spectra, not as a sampled
function (flux and wavelength), but as a linear combination of basis functions,
although sampled spectra can easily be derived from them.Comment: 20 pages, 22 figure
Resolving Globular Cluster Formation within a Cosmological Context
We place constraints on the formation redshifts for blue globular clusters
(BGCs), independent of the details of hydrodynamics and population III star
formation. The observed radial distribution of BGCs in the Milky Way Galaxy
suggests that they formed in biased dark matter halos at high redshift. As a
result, simulations of a ~1 Mpc box up to z~10 must resolve BGC formation in
LCDM. We find that most halo stars could be produced from destroyed BGCs and
other low-mass clusters that formed at high redshift. We present a
proof-of-concept simulation that captures the formation of globular-like star
clusters.Comment: Accepted for publication in ApJ
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