754 research outputs found
Testing Ultrafast Two-Photon Spectral Amplitudes via Optical Fibres
We test two-dimensional TPSA of biphoton light emitted via ultrafast
spontaneous parametric down-conversion (SPDC) using the effect of
group-velocity dispersion in optical fibres. Further, we apply this technique
to demonstrate the engineering of biphoton spectral properties by acting on the
pump pulse shape
Perspective: Polarizable continuum models for quantum-mechanical descriptions
Polarizable continuum solvation models are nowadays the most popular approach to describe solvent effects in the context of quantum mechanical calculations. Unexpectedly, despite their widespread use in all branches of quantum chemistry and beyond, important aspects of both their theoretical formulation and numerical implementation are still not completely understood. In particular, in this perspective we focus on the numerical issues of their implementation when applied to large systems and on the theoretical framework needed to treat time dependent problems and excited states or to deal with electronic correlation. Possible extensions beyond a purely electrostatic model and generalizations to environments beyond common solvents are also critically presented and discussed. Finally, some possible new theoretical approaches and numerical strategies are suggested to overcome the obstacles which still prevent a full exploitation of these models
Performance of the diamond active target prototype for the PADME experiment at the DANE BTF
The PADME experiment at the DANE Beam-Test Facility (BTF) is designed
to search for the gauge boson of a new interaction in the process
ee+, using the intense positron beam hitting a
light target. The , usually referred as dark photon, is assumed to
decay into invisible particles of a secluded sector and it can be observed by
searching for an anomalous peak in the spectrum of the missing mass measured in
events with a single photon in the final state. The measurement requires the
determination of the 4-momentum of the recoil photon, performed by a
homogeneous, highly segmented BGO crystals calorimeter. A significant
improvement of the missing mass resolution is possible using an active target
capable to determine the average position of the positron bunch with a
resolution of less than 1 mm. This report presents the performance of a real
size PADME active target made of a thin (50 m) diamond
sensor, with graphitic strips produced via laser irradiation on both sides. The
measurements are based on data collected in a beam test at the BTF in November
2015.Comment: 7 pages, 10 figure
Realization and characterization of graphitic contacts on diamond by means of laser
This work deals with the realization and characterization of integrated graphitic contacts on diamond by means of laser irradiation (graphitization), in order to obtain good quality ohmic electrodes for nuclear radiation detectors to be used in high energy physics experiments. Unlike the conventional method used for the electrode production, which requires numerous steps and very well controlled environmental conditions, this alternative technique presents many advantages: the contacts are realized in air at room temperature in a single step. In this study, the characteristics of several graphitic structures realized on a diamond surface by changing the radiation-matter interaction parameters have been evaluated in order to define the best experimental conditions to create graphitic electrodes with low resistivity. The obtained results are promising: contacts perfectly adherent, with good charge collection properties, stable and resistant to ionizing radiation
Radiation Damage of Polycrystalline CVD Diamond with Graphite Electrical Contacts
In this work we show preliminary results of radiation damage for a polycrystalline diamond with graphite contacts in terms of time response after 62 MeV protons irradiation for a total fluence of (2.0±0.08)×1015 protons/cm2. In addition, we describe the realization of a new type of device made with graphite micro-strips by laser micro-writing on diamond surface. In this way we made 20 graphite micro-strips of width about 87 m and spacing between each other of about 60 m
Diamond detectors with electrodes graphitized by means of laser
In the last years there has been an increase of interest in diamond devices because of the promising applications in different field, such as high-energy physics, radiotherapy and biochemical applications. In particular, a new frontier is represented by the realization of full-carbon detectors characterized by graphite electrodes, which give to the devices considerable advantages like high radiation hardness, perfect mechanical adhesion and good charge collection properties. In this paper the manufacturing of full-carbon devices and their detection performances are illustrated and compared to a reference diamond detector characterized by traditional electrodes
RAMAN spectroscopy imaging improves the diagnosis of papillary thyroid carcinoma
Recent investigations strongly suggest that Raman spectroscopy (RS) can be used as a clinical tool in
cancer diagnosis to improve diagnostic accuracy. In this study, we evaluated the efficiency of Raman
imaging microscopy to discriminate between healthy and neoplastic thyroid tissue, by analyzing
main variants of Papillary Thyroid Carcinoma (PTC), the most common type of thyroid cancer. We
performed Raman imaging of large tissue areas (from 100 × 100 μm2 up to 1 × 1 mm2), collecting
38 maps containing about 9000 Raman spectra. Multivariate statistical methods, including Linear
Discriminant Analysis (LDA), were applied to translate Raman spectra differences between healthy and
PTC tissues into diagnostically useful information for a reliable tissue classification. Our study is the first
demonstration of specific biochemical features of the PTC profile, characterized by significant presence
of carotenoids with respect to the healthy tissue. Moreover, this is the first evidence of Raman spectra
differentiation between classical and follicular variant of PTC, discriminated by LDA with high efficiency.
The combined histological and Raman microscopy analyses allow clear-cut integration of morphological
and biochemical observations, with dramatic improvement of efficiency and reliability in the differential
diagnosis of neoplastic thyroid nodules, paving the way to integrative findings for tumorigenesis and
novel therapeutic strategies
A five-year survey for plastic surgery malpractice claims in Rome, Italy
(1) Introduction: Medical malpractice claims against both health institutions and physicians are a crucial topic in Italy, as well as in other countries, particularly regarding civil proceedings. Our study reports an analysis of all of the malpractice judgments concerning plastic surgery decided in the Civil Court of Rome between 2012 and 2016. (2) Methods: the database of the Observatory Project on Medical Responsibility (ORMe) was analyzed, which collects all of the judgments of the Civil Court of Rome, that is, the first instance district court. Therefore, neither the jurisprudence of the second level court nor that of the Supreme Court was taken into account. (3) Results: 144 judgments concerning plastic surgery were delivered in the five-year period of 2012–2016 (corresponding to 10.6% of total professional liability verdicts of the Civil Court of Rome in the same period). In 101/144 cases (70.14%), the claim was accepted. A total of €4,727,579.00 was paid in compensation for plastic surgery malpractice claims, with a range from a minimum amount of €1555.96 to a maximum amount of €1,425,155.00 and an average compensation of €46,807.71 per claim that was significantly lower compared to other surgical disciplines. (4) Conclusions: Our data confirm that the analyzed branch has a high litigation rate, with a prevalence of convictions for cosmetic procedures over reconstructive ones, both for malpractice and for violation of the informed consent. Plastic surgery is also confirmed among those branches in which the professionals are more frequently sued compared to health institutions
Stereospecific generation of homochiral helices in coordination polymers built from enantiopure binaphthyl-based ligands
The novel enantiopure spacer 2,2′-dimethoxy-1,1′-binaphthyl-3,3′-bis(4-pyridyl-amido) has been designed to prepare helical coordination polymers here investigated by means of experimental and theoretical data
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