305 research outputs found
Asymmetric Organocatalysis-A Powerful Technology Platform for Academia and Industry: Pregabalin as a Case Study
Enantioselective organocatalysis has quickly established itself as the third pillar of asymmetric catalysis. It is a powerful technology platform, and it has a tremendous impact in both academic and industrial settings. By focusing on pregabalin, as a case study, this Perspective aims to show how a process amenable to industry of a simple chiral molecule can be tackled in several different ways using organocatalysis
Exploring low-degree nodes first accelerates network exploration
We consider information diffusion on Web-like networks and how random walks can simulate it.
A well-studied problem in this domain is Partial Cover Time, i.e., the calculation of the expected number of steps a random walker needs to visit a given fraction of the nodes of the network.
We notice that some of the fastest solutions in fact require that nodes have perfect knowledge of the degree distribution of their neighbors, which in many practical cases is not obtainable, e.g., for privacy reasons.
We thus introduce a version of the Cover problem that considers such limitations: Partial Cover Time with Budget.
The budget is a limit on the number of neighbors that can be inspected for their degree; we have adapted optimal random walks strategies from the literature to operate under such budget.
Our solution is called Min-degree (MD) and, essentially, it biases random walkers towards visiting peripheral areas of the network first.
Extensive benchmarking on six real datasets proves that the---perhaps counter-intuitive strategy---MD strategy is in fact highly competitive wrt. state-of-the-art algorithms for cover
Intense terahertz pulses from SPARC-LAB coherent radiation source
The linac-based Terahertz source at the SPARC_LAB test facility is able to gene
rate highly intense Terahertz broadband
pulses
via
coherent transition radiation (CTR) from high brightness electron beams. The THz pulse duration is typically
down to 100 fs RMS and can be tuned through the electron bunch duration and shaping. The measured stored energy in a
single THz pulse has reached 40
ÎĽ
J, which corresponds to a peak
electric field of 1.6 MV/cm at the THz focus. Here we
present the main features, in particular spatial and sp
ectral distributions and energy
characterizations of the
SPARC_LAB THz source, which is very competitive for investigations in Condensed Matter, as well as a valid tool for
electron beam longitudinal diagnostics
Factors Associated with Adherence to the Mediterranean Diet among Adolescents Living in Sicily, Southern Italy
The present study aimed to examine the factors associated with increased Mediterranean diet (MD) adherence among a sample of Italian adolescents. A cross-sectional survey was conducted on 1135 students (13–16 years) attending 13 secondary schools of Sicily, southern Italy. Validated instruments were used for dietary assessment and the KIDMED score to assess adolescents’ adherence to the MD. A higher adherence to the MD was associated with high socioeconomic status (Odds Ratio [OR] 1.53, 95% Confidence Interval [CI]: 1.03–2.26) and high physical activity (OR 1.19, 95% CI: 1.02–1.70), whereas lower adherence was associated with living in an urban environment (OR 0.65, 95% CI: 0.44–0.97) and being obese (OR 0.59, 95% CI: 0.37–0.94). The adolescents’ KIDMED scores were inversely associated with adolescents’ intake of sweets, fast foods, fried foods, and sugary drinks, and directly with fruit, vegetables, pasta, fish, and cheese intakes. Urban-living adolescents were less likely to eat fruit and more prone to consume meat, sugary drinks, and fast food than rural-living adolescents. The latter were more likely to eat sweets and snacks. A general poor quality of food consumption in Italian adolescents away from the MD was reported, especially among those living in urban areas
The Palermo (Sicily) seismic cluster of September 2002, in the seismotectonic framework of the Tyrrhenian Sea-Sicily border area
The northern coast of Sicily and its offshore area represent a hinge zone between a sector of the Tyrrhenian
Basin, characterized by the strongest crustal thinning, and the sector of the Sicilian belt which has emerged. This
hinge zone is part of a wider W-E trending right-lateral shear zone, which has been affecting the Maghrebian
Chain units since the Pliocene. Seismological and structural data have been used to evaluate the seismotectonic
behavior of the area investigated here. Seismological analysis was performed on a data set of about 2100 seismic
events which occurred between January 1988 and October 2002 in the Southern Tyrrhenian Sea. This paper
focuses in particular on a set of data relating to the period from 6th September 2002, including both the main
shock and about 540 aftershocks of the Palermo seismic sequence. The distribution of the hypocenters revealed
the presence of two main seismogenic zones. The events of the easternmost zone may be related to the Ionian
lithospheric slab diving beneath the Calabrian Arc. The seismicity associated with the westernmost zone is closely
clustered around a sub-horizontal regression plane contained within the thinned Southern Tyrrhenian crust,
hence suggesting that this seismogenic zone is strictly connected to the deformation field active within the hinge
zone. On the basis of both structural and seismological data, the brittle deformation pattern is characterized by
high-angle faults, mainly represented by transcurrent synthetic right-lateral and antithetic left-lateral systems,
producing both restraining/uplifting and releasing/subsiding zones which accommodate strains developing in response
to the current stress field (characterized by a maximum axis trending NW-SE) which has been active in
the area since the Pliocene. The cluster of the seismic sequence which started with the 6th September 2002's
main shock is located within the hinge zone. The distribution of the hypocenters relative to this sequence emphasizes
the presence of a high-angle NE-SW-oriented deformation belt within which several shear surfaces are
considered to be found sub-parallel to that established for the main shock. The kinematics of all these structures
is consistent with a compressive right-lateral focal mechanism
Twenty years of experience in juvenile nasopharyngeal angiofibroma (JNA) preoperative endovascular embolization: An effective procedure with a low complications rate
Juvenile nasopharyngeal angiofibroma (JNA) is a benign tumor of the nasal cavity that predominantly affects young boys. Surgical removal remains the gold standard for the management of this disease. Preoperative intra-arterial embolization (PIAE) is useful for reductions in intraoperative blood loss and surgical complications. In our series of 79 patients who underwent preoperative embolization from 1999 to 2020, demographics, procedural aspects, surgical management and follow-up outcome were analyzed. Embolization was performed in a similar fashion for all patients, with a superselective microcatheterization of external carotid artery (ECA) feeders and an injection of polyvinyl alcohol (PVA) particles, followed, in some cases, by the deployment of coils. Procedural success was reached in 100% of cases, with no complications such as bleeding or thromboembolic occlusion, and surgical intraoperative blood loss was significantly decreased. In conclusion, PIAE is a safe and effective technique in JNA treatment, minimizing intraoperative bleeding
Patterns and trends of utilization of incretin-based medicines between 2008 and 2014 in three Italian geographic areas
Background: The incretin-based medicines GLP1 analogues (GLP1a) and dipeptidyl peptidase-4 inhibitors (DPP4i) are hypoglycaemic agents licensed for the treatment of type 2 diabetes mellitus (T2DM). Although these drugs possess comparable efficacy and low risk of hypoglycaemia, differences in terms of route of administration (subcutaneous versus oral), effect on body weight and gastrointestinal tolerabily can impact their actual use in clinical practice. This study aimed to describe the real-world utilization of incretin-based medicines in the Italian clinical practice. Methods: A multi-database, population-based, descriptive, cohort study was performed using administrative data collected between 2008 and 2014 from three Italian geographic areas. Subjects aged 6518 were selected. New users were defined as those with 651 dispensing of GLP1a or DPP4i during the year of interest and none in the past. Trends of cumulative annual incidence of use in the general adult population were observed. New users of GLP1a or DPP4i were respectively described in terms of demographic characteristics and use of antidiabetic drugs during 1 year before and after the first incretin dispensing. Results: The overall study population included 4,943,952 subjects. A total of 7357 new users of GLP1a and 41,907 of DPP4i were identified during the study period. Incidence of use increased between 2008 (0.2\u2030 for both GLP1a and DPP4i) and 2011 (GLP1a = 0.6\u2030; DPP4i = 2.5\u2030) and slightly decreased thereafter. In 2014, 61% of new GLP1a users received once-daily liraglutide while 52% of new DPP4i users received metformin/DPP4i in fixed-dose. The percentage of new DPP4i users older than 65 years of age increased from 30.9 to 62.6% during the study period. Around 12% of new users had not received any antidiabetic before starting an incretin. Conclusions: During the study period, DPP4i rapidly became the most prescribed incretin-based medicine, particularly among older new user. The choice of the specific incretin-based medicine at first prescription appeared to be directed towards those with higher convenience of use (e.g. oral DPP4i rather than subcutaneous GLP1a, once-daily liraglutide rather than twice-daily exenatide). The non-negligibile use of incretin-based medicines as first-line pharmacotherapy for T2DM warrants further effectiveness and safety evaluations to better define their place in therapy
Non-adhesive liquid embolic agents in extra-cranial district: State of the art and review of the literature
This review focuses on the use of “new” generation of non-adhesive liquid embolic agents (NALEA). In literature, non-adhesive liquid embolic agents have mainly been used in the cerebral district; however, multiple papers describing the use of NALEA in the extracranial district have been published recently and the aim of this review is to explore and analyze this field of application. There are a few NALEA liquids such as Onyx, Squid, and Phil currently available in the market, and they are used in the following applications: mainly arteriovenous malformations, endoleaks, visceral aneurysm or pseudoaneurysm, presurgical and hypervascular lesions embolization, and a niche of percutaneous approaches. These types of embolizing fluids can be used alone or in combination with other embolizing agents (such as coils or particles) so as to enhance its embolizing effect or improve its possible defects. The primary purpose of this paper is to evaluate the use of NALEAs, predominantly used alone, in elective embolization procedures. We did not attempt a meta-analysis due to the data heterogeneity, high number of case reports, and the lack of a consistent follow-up time period
First single-shot and non-intercepting longitudinal bunch diagnostics for comb-like beam by means of Electro-Optic Sampling
At SPARC-LAB,we have installed an Electro-Optic Sampling(EOS)experiment for single shot,non-
destructive measurements of the longitudinal distribution charge of individual electron bunches.The
profile of the electron bunch field is electro-optically encoded into aTi:Sa laser, having 130fs(rms)pulse
length, directly derived from the photocathode's laser. The bunch profile information is spatially
retrieved,i.e.,the laser crosses with an angle of 30 degrees with respect to the normal to the surface of EO
crystal(ZnTe,GaP)and the bunch longitudinal profile is mapped into the laser's transverse profile.
In particular,we used the EOS for a single-shot direct visualization of the time profile of a comb-like
electron beam,consisting of two bunches, about 100fs(rms)long,sub-picosecond spaced with a total
charge of 160pC. The electro-optic measurements(done with both ZnTe and GaP crystals)have been
validated with both RF Deflector (RFD)and Michelson interferometer measurements
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