145 research outputs found
Identification and quantification protocol of hazardous-metal bearing minerals: Ni in serpentinite rocks from Valmalenco (Sondrio, Central Alps, Northern Italy)
Serpentinite is a widespread rock type used worldwide as building material. Heavy metals like Ni in both the serpentinite products and serpentinite mining wastes pose potential environmental and health issues. This work devises an analytical protocol to identify and quantify the Ni speciation in the mineralogical matrix, through: i) bulk Ni quantification; ii) quantitative mineralogical and chemical analysis of each Ni-rich mineral; iii) comparison of bulk analysis results with the sum of each contribution from the Ni-rich minerals. As case study, two commercial serpentinites "Verde Giada" (VG) and "Verde Vittoria" (VV) from Valmalenco (Northern Italy) were analysed by ICP-MS, XRPD, TGA-MSEGA, SEM, TEM, EPMA, and micro-Raman spectroscopy. The bulk Ni content is 1500-1750 mg/kg and 1390-1620 mg/kg for VG and VV, respectively. The major minerals from XRPD and EPMA (antigorite, olivine, pyroxene, magnetite, brucite) account for 1094 and 1291 mg/kg of Ni for VG and VV, respectively. SEM/TEM and EPMA highlighted the presence of minor chrysotile, pentlandite, heazlewoodite, awaruite, rising the computed Ni to 1924 and 1761 mg/kg for VG and VV, in good agreement with bulk ICP-MS. This protocol provides robust results and can thus enhance the exposure assessment of Ni and eventually other naturally occurring hazardous metals
Isolated ovarian follicle culture: a promising strategy for fertility preservation
Ovarian tissue cryopreservation represents one among the most preferred strategies for fertility preservation currently. However, concerns regarding the transmission of malignant cells during the transplantion of stored ovarian tissues, is a major restraint in recommending the procedure to patients diagnosed with all kinds of malignant disorders.
On the contrary, use of isolated follicles for restoration of fertility in such patients could completely evade the possibility of cancer re-introduction after treatment. Follicles housed in the ovarian environment in vivo prevail under the mechanical and the chemical/nutritional support of the ovary. Although not complete, recent knowledge about the dynamics of follicular progression has led to improvements in the culture system adopted.
This review aims at summarising the culture of isolated follicles in vitro, particularly emphasising the efforts made to mechanically and nutritionally support the follicle. Advances in follicular culture systems could prove useful to highly improve the efficiency of current fertility restoration strategies and evade the concerns associated with the same
SWIPE: a bolometric polarimeter for the Large-Scale Polarization Explorer
The balloon-borne LSPE mission is optimized to measure the linear
polarization of the Cosmic Microwave Background at large angular scales. The
Short Wavelength Instrument for the Polarization Explorer (SWIPE) is composed
of 3 arrays of multi-mode bolometers cooled at 0.3K, with optical components
and filters cryogenically cooled below 4K to reduce the background on the
detectors. Polarimetry is achieved by means of large rotating half-wave plates
and wire-grid polarizers in front of the arrays. The polarization modulator is
the first component of the optical chain, reducing significantly the effect of
instrumental polarization. In SWIPE we trade angular resolution for
sensitivity. The diameter of the entrance pupil of the refractive telescope is
45 cm, while the field optics is optimized to collect tens of modes for each
detector, thus boosting the absorbed power. This approach results in a FWHM
resolution of 1.8, 1.5, 1.2 degrees at 95, 145, 245 GHz respectively. The
expected performance of the three channels is limited by photon noise,
resulting in a final sensitivity around 0.1-0.2 uK per beam, for a 13 days
survey covering 25% of the sky.Comment: In press. Copyright 2012 Society of Photo-Optical Instrumentation
Engineers. One print or electronic copy may be made for personal use only.
Systematic reproduction and distribution, duplication of any material in this
paper for a fee or for commercial purposes, or modification of the content of
the paper are prohibite
large area superconducting tes spiderweb bolometer for multi mode cavity microwave detect
For the cosmic microwave background, the increase of the sensitivity of present superconducting TES Spiderweb Bolometers can be done coupling them to a large set of modes of the EM radiation inside the cavity. This will require a proper shaping of the horn-cavity assembly for the focal plane of the microwave telescope and the use of large area bolometers. Large area spiderweb bolometers of 8 mm diameter and a mesh size of 250 ÎŒm are fabricated in order to couple with approximately the first 20 modes of the cavity at about 140 GHz. These bolometers are fabricated with micro machining techniques from silicon wafer covered with SiO2 â Si3N4 CVD thick films, 0.3 ÎŒm and 1 ÎŒm respectively. The sensor is a Ti/Au/Ti 3 layer TES sensor with Tc tuned in the 330-380 mK and 2 mK transition width. The TES is electronically coupled to the EM gold absorber that is grown on to the spiderweb mesh in order to sense the temperature of the electron gas heated by the EM radiation. The gold absorber mesh has 5 um beam size over a Si3N4 10 ÎŒm beam size supporting mesh. The Si3N4 mesh is then fully suspended by means of DRIE back etching of the Si substrate. Here we present the first results of these large area bolometers
Design of 280 GHz feedhorn-coupled TES arrays for the balloon-borne polarimeter SPIDER
We describe 280 GHz bolometric detector arrays that instrument the
balloon-borne polarimeter SPIDER. A primary science goal of SPIDER is to
measure the large-scale B-mode polarization of the cosmic microwave background
in search of the cosmic-inflation, gravitational-wave signature. 280 GHz
channels aid this science goal by constraining the level of B-mode
contamination from galactic dust emission. We present the focal plane unit
design, which consists of a 1616 array of conical, corrugated feedhorns
coupled to a monolithic detector array fabricated on a 150 mm diameter silicon
wafer. Detector arrays are capable of polarimetric sensing via waveguide
probe-coupling to a multiplexed array of transition-edge-sensor (TES)
bolometers. The SPIDER receiver has three focal plane units at 280 GHz, which
in total contains 765 spatial pixels and 1,530 polarization sensitive
bolometers. By fabrication and measurement of single feedhorns, we demonstrate
14.7 FHWM Gaussian-shaped beams with 1% ellipticity in a 30%
fractional bandwidth centered at 280 GHz. We present electromagnetic
simulations of the detection circuit, which show 94% band-averaged,
single-polarization coupling efficiency, 3% reflection and 3% radiative loss.
Lastly, we demonstrate a low thermal conductance bolometer, which is
well-described by a simple TES model and exhibits an electrical noise
equivalent power (NEP) = 2.6 10 W/,
consistent with the phonon noise prediction.Comment: Proceedings of SPIE Astronomical Telescopes + Instrumentation 201
First Results of the “Carbonaceous Aerosol in Rome and Environs (CARE)” Experiment: Beyond Current Standards for PM10
In February 2017 the âCarbonaceous Aerosol in Rome and Environs (CARE)â experiment was carried out in downtown Rome to address the following specific questions: what is the color, size, composition, and toxicity of the carbonaceous aerosol in the Mediterranean urban background area of Rome? The motivation of this experiment is the lack of understanding of what aerosol types are responsible for the severe risks to human health posed by particulate matter (PM) pollution, and how carbonaceous aerosols influence radiative balance. Physicochemical properties of the carbonaceous aerosol were characterised, and relevant toxicological variables assessed. The aerosol characterisation includes: (i) measurements with high time resolution (min to 1â2 h) at a fixed location of black carbon (eBC), elemental carbon (EC), organic carbon (OC), particle number size distribution (0.008â10 ÎŒ m), major non refractory PM1 components, elemental composition, wavelength-dependent optical properties, and atmospheric turbulence; (ii) 24-h measurements of PM10 and PM2.5 mass concentration, water soluble OC and brown carbon (BrC), and levoglucosan; (iii) mobile measurements of eBC and size distribution around the study area, with computational fluid dynamics modeling; (iv) characterisation of road dust emissions and their EC and OC content. The toxicological assessment includes: (i) preliminary evaluation of the potential impact of ultrafine particles on lung epithelia cells (cultured at the air liquid interface and directly exposed to particles); (ii) assessment of the oxidative stress induced by carbonaceous aerosols; (iii) assessment of particle size dependent number doses deposited in different regions of the human body; (iv) PAHs biomonitoring (from the participants into the mobile measurements). The first experimental results of the CARE experiment are presented in this paper. The objective here is to provide baseline levels of carbonaceous aerosols for Rome, and to address future research directions. First, we found that BC and EC mass concentration in Rome are larger than those measured in similar urban areas across Europe (the urban background mass concentration of eBC in Rome in winter being on average 2.6 ± 2.5 ÎŒ g · m â 3 , mean eBC at the peak level hour being 5.2 (95% CI = 5.0â5.5) ÎŒ g · m â 3 ). Then, we discussed significant variations of carbonaceous aerosol properties occurring with time scales of minutes, and questioned on the data averaging period used in current air quality standard for PM 10 (24-h). Third, we showed that the oxidative potential induced by aerosol depends on particle size and composition, the effects of toxicity being higher with lower mass concentrations and smaller particle size. Albeit this is a preliminary analysis, findings reinforce the need for an urgent update of existing air quality standards for PM 10 and PM 2.5 with regard to particle composition and size distribution, and data averaging period. Our results reinforce existing concerns about the toxicity of carbonaceous aerosols, support the existing evidence indicating that particle size distribution and composition may play a role in the generation of this toxicity, and remark the need to consider a shorter averaging period (<1 h) in these new standards
A Multicenter Retrospective Survey regarding Diabetic Ketoacidosis Management in Italian Children with Type 1 Diabetes
We conducted a retrospective survey in pediatric centers belonging to the Italian Society for Pediatric Diabetology and Endocrinology. The following data were collected for all new-onset diabetes patients aged 0-18 years: DKA (pH < 7.30), severe DKA (pH < 7.1), DKA in preschool children, DKA treatment according to ISPAD protocol, type of rehydrating solution used, bicarbonates use, and amount of insulin infused. Records (n = 2453) of children with newly diagnosed diabetes were collected from 68/77 centers (87%), 39 of which are tertiary referral centers, the majority of whom (n = 1536, 89.4%) were diagnosed in the tertiary referral centers. DKA was observed in 38.5% and severe DKA in 10.3%. Considering preschool children, DKA was observed in 72%, and severe DKA in 16.7%. Cerebral edema following DKA treatment was observed in 5 (0.5%). DKA treatment according to ISPAD guidelines was adopted in 68% of the centers. In the first 2 hours, rehydration was started with normal saline in all centers, but with different amount. Bicarbonate was quite never been used. Insulin was infused starting from third hour at the rate of 0.05-0.1 U/kg/h in 72% of centers. Despite prevention campaign, DKA is still observed in Italian children at onset, with significant variability in DKA treatment, underlying the need to share guidelines among centers
Science case study and scientific simulations for the enhanced X-ray Timing Polarimetry mission, eXTP
The X-ray astronomy mission eXTP (enhanced X-ray Timing Polarimetry) is designed to study matter under extreme conditions of density, gravity and magnetism. Primary
goals are the determination of the equation of state (EoS) of matter at supranuclear density,
the physics in extremely strong magnetic fields, the study of accretion in strong-field gravity
(SFG) regime. Primary targets include isolated and binary neutron stars, strong magneticfield systems like magnetars, and stellar-mass and supermassive black holes. In this paper
we report about key observations and simulations with eXTP on the primary objectives
involving accretion under SFG regimes and determination of NS-Eo
CMB-S4: Forecasting Constraints on Primordial Gravitational Waves
CMB-S4---the next-generation ground-based cosmic microwave background (CMB)
experiment---is set to significantly advance the sensitivity of CMB
measurements and enhance our understanding of the origin and evolution of the
Universe, from the highest energies at the dawn of time through the growth of
structure to the present day. Among the science cases pursued with CMB-S4, the
quest for detecting primordial gravitational waves is a central driver of the
experimental design. This work details the development of a forecasting
framework that includes a power-spectrum-based semi-analytic projection tool,
targeted explicitly towards optimizing constraints on the tensor-to-scalar
ratio, , in the presence of Galactic foregrounds and gravitational lensing
of the CMB. This framework is unique in its direct use of information from the
achieved performance of current Stage 2--3 CMB experiments to robustly forecast
the science reach of upcoming CMB-polarization endeavors. The methodology
allows for rapid iteration over experimental configurations and offers a
flexible way to optimize the design of future experiments given a desired
scientific goal. To form a closed-loop process, we couple this semi-analytic
tool with map-based validation studies, which allow for the injection of
additional complexity and verification of our forecasts with several
independent analysis methods. We document multiple rounds of forecasts for
CMB-S4 using this process and the resulting establishment of the current
reference design of the primordial gravitational-wave component of the Stage-4
experiment, optimized to achieve our science goals of detecting primordial
gravitational waves for at greater than , or, in the
absence of a detection, of reaching an upper limit of at CL.Comment: 24 pages, 8 figures, 9 tables, submitted to ApJ. arXiv admin note:
text overlap with arXiv:1907.0447
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