4,049 research outputs found
Charge carrier generation in a conjugated polymer studied via ultrafast pump-push-probe experiments
Conjugated polymers find rapidly growing application in electroluminescent displays and are extensively studied for use in photovoltaics and laser diodes. For a wide range of conjugated materials ultrafast pump-probe experiments have revealed the excited state dynamics of singlet and triplet excitons as well as positively and negatively charged polarons. Charge carriers play a key role in all the above mentioned applications. However, there is yet no clear picture of the mechanisms which lead to their generation. Photocurrent excitation cross-correlation measurement on methyl-substituted ladder-type poly(para)phenyl (m-LPPP), a prototypical conjugated polymer with very appealing properties for the above mentioned applications, have suggested that charge carrier generation occurs preferentially from higher lying states during energy migration. Our approach to examining this mechanism consists of an innovative modification of the ultrafast time-resolved pump-probe technique
Spatial organization of seismicity and fracture pattern in NE Italy and W Slovenia
Abstract The study focuses on the spatial organization of seismicity and the relation between fracture pattern and earthquakes in the Friuli (north-eastern Italy) and western Slovenia seismic regions. The structural setting is characterized by a complex structure resulting from the superposition of several tectonic phases that generated NWSE trending Dinaric faults and about E-W trending Alpine faults. The upper crust is characterized by lithological and mechanical heterogeneities. The fractal analysis shows that, in general, the seismicity only partially fills a plane. Only in a few cases, the earthquakes distribute on planar structures. The orientation of planes that fit through the hypocentres shows a different disposition at the two depth intervals analysed. The shallower interval (0\u201310 km) is characterized by planes with highly variable orientations. The spatial seismicity is investigated in the context of a general damage model, represented by the crack density distribution. The results evidence that the seismicity appears mostly located along sharp transition areas from low crack density to higher crack density, i.e., from zones of low damage to zones of intermediate damage. These zones are characterized by high heterogeneity due to the superposition of different tectonic phases and by the maximum interference between Dinaric and Alpine domains. The orientation of the planes fitting the seismicity at 10\u201320-km depth appears less dispersed, coinciding with the trend of Dinaric subvertical faults in the northern and eastern parts of the study area, and with Alpine low-angle faults in the western and southern parts
Assembling and Verification of a Fitness Test Battery for the Recruitment of the Swiss Army and Nation-Wide Use
The aim of this study was to assess the reliability, validity and feasibility of selected physical performance tests, to compile a new fi tness test battery based on these results and to obtain standard values for young men. 79 men (20.3 ± 1.1 y) performed the tests for the reliability part, while 60 men (20.3 ± 1.1 y) completed the tests for the validity part of the study. Feasibility was confi rmed by 25 sport experts who conducted the test battery among 1704 men (19.5 ± 1.0 y). For standard values, the data of 12 862 men (19.9 ± 1.0 y) were collected. Based on the reliability and validity data, the following 5 tests were selected for the fi tness-test battery: 1) progressive endurance run, 2) seated 2-kg-shot put, 3) standing long jump, 4) trunk muscle strength test and 5) 1-leg standing test. The reliability and validity of the selected performance tests were suffi cient to very good (r = 0.50–0.90 and r = 0.64–0.91, respectively). The suggested fi tness-test battery can be applied among large groups
The coherent dynamics of photoexcited green fluorescent proteins
The coherent dynamics of vibronic wave packets in the green fluorescent
protein is reported. At room temperature the non-stationary dynamics following
impulsive photoexcitation displays an oscillating optical transmissivity
pattern with components at 67 fs (497 cm-1) and 59 fs (593 cm-1). Our results
are complemented by ab initio calculations of the vibrational spectrum of the
chromophore. This analysis shows the interplay between the dynamics of the
aminoacidic structure and the electronic excitation in the primary optical
events of green fluorescent proteins.Comment: accepted for publication in Physical Review Letter
Solid-phase microextraction/gas chromatography–mass spectrometry method optimization for characterization of surface adsorption forces of nanoparticles
A complete characterization of the different physical chemical properties of nanoparticles (NPs) is necessary for the evaluation of their impact on health and environment. Among these properties, the surface characterization of the nanomaterial is the least developed and in many cases limited to the measurement of surface composition and Zeta potential. The biological surface adsorption index approach (BSAI) for characterization of surface adsorption properties of nanoparticles (NPs) has been recently introduced [1,2]. BSAI approach offers in principle the possibility to characterize the different interaction forces exerted between a nanomaterial surface and an organic –and by extension biological- entity. The present work develops further the BSAI approach of and optimizes a solid-phase microextraction – gas chromatography mass spectrometry (SPME/GC-MS) method, which is applied to measure the adsorption properties of different nanomaterials taking into account their specific surface area. This approach gives thus a better defined quantification of the adsorption properties on NPs.
To optimize the SPME/GC-MS method, we investigated the various aspects of the process including: kinetics of adsorption of probe compounds on SPME fiber, kinetic of adsorption of probe compounds on NPs surface, and optimization of NPs concentration. The optimized conditions were then tested on 33 probe compounds and on Au NPs (15 nm) and SiO2 NPs (50 nm).
The results demonstrated that this detailed optimization of the SPME/GC-MS method under various conditions is a critical factor and pre-requisite to the application of BSAI approach as a tool to characterize surface adsorption properties of NPs and therefore to any further conclusions on their potential impact on health.JRC.I.4-Nanobioscience
CVA6 RISC-V Virtualization: Architecture, Microarchitecture, and Design Space Exploration
Virtualization is a key technology used in a wide range of applications, from
cloud computing to embedded systems. Over the last few years, mainstream
computer architectures were extended with hardware virtualization support,
giving rise to a set of virtualization technologies (e.g., Intel VT, Arm VE)
that are now proliferating in modern processors and SoCs. In this article, we
describe our work on hardware virtualization support in the RISC-V CVA6 core.
Our contribution is multifold and encompasses architecture, microarchitecture,
and design space exploration. In particular, we highlight the design of a set
of microarchitectural enhancements (i.e., G-Stage Translation Lookaside Buffer
(GTLB), L2 TLB) to alleviate the virtualization performance overhead. We also
perform a Design Space Exploration (DSE) and accompanying post-layout
simulations (based on 22nm FDX technology) to assess Performance, Power ,and
Area (PPA). Further, we map design variants on an FPGA platform (Genesys 2) to
assess the functional performance-area trade-off. Based on the DSE, we select
an optimal design point for the CVA6 with hardware virtualization support. For
this optimal hardware configuration, we collected functional performance
results by running the MiBench benchmark on Linux atop Bao hypervisor for a
single-core configuration. We observed a performance speedup of up to 16%
(approx. 12.5% on average) compared with virtualization-aware non-optimized
design at the minimal cost of 0.78% in area and 0.33% in power. Finally, all
work described in this article is publicly available and open-sourced for the
community to further evaluate additional design configurations and software
stacks
Management of newly diagnosed patients with type 2 diabetes: What are the attitudes of physicians? A SUBITO!AMD survey on the early diabetes treatment in Italy
Early intensive therapy in type 2 diabetes can
prevent complications. Nevertheless, metabolic control is
often sub-optimal in newly diagnosed patients. This webbased
survey aimed to evaluate opinions of physicians
about treatment, priorities, and barriers in the care of
patients first referred to diabetes clinics. Data on physician
attitudes toward therapeutic preferences for two clinical
case models (same clinical profile, except HbA1c levels of
8.6 and 7.3% at the first access, respectively) were collected.
Participants were asked to rank from 1 (most
important) to 6 (least important) a list of priorities and
barriers associated with the care of new patients. Overall,
593 physicians participated. In both case models, metformin
and education were primary options, although their
combination with other classes of drugs varied substantially.
Main priorities were ‘‘to teach the patient how to
cope with the disease’’ and ‘‘to achieve HbA1c target’’;
main barriers were ‘‘lack of time’’ and ‘‘long waiting list’’.
At multivariate analyses, physicians from the South of Italy
had a twofold higher likelihood to attribute a rank 1–2 to
organizational barriers than those operating in the North
(South vs. North: OR: 2.4; 95% CI 1.4–4.1; Center vs.
North: OR: 2.4; 95% CI 0.9–3.2). In the absence of a
widely accepted evidence-based therapeutic algorithm
driving the therapeutic choices according to the patient
characteristics, prescriptions vary according to physician
preferences. Education is perceived as a key-strategy, but
organizational barriers and geographic disparities are an
obstacle. These findings can drive new strategies to reduce
clinical inertia, attitudes variability, and geographic
disparities
Endovascular management of massive post-partum haemorrhage in abnormal placental implantation deliveries
Objectives: To retrospectively evaluate safety and efficacy of pelvic artery embolisation (PAE) in post-partum haemorrhage (PPH) in abnormal placental implantation (API) deliveries. Methods: From January 2009 to November 2013, 12 patients with API and intractable intraoperative PPH underwent PAE after caesarean delivery to control a haemorrhage (in four of these cases after hysterectomy). Arterial access was obtained prior to the delivery; PAE was performed in the obstetrics operating room by an interventional radiologist that was present with an interventional radiology (IR) team during the delivery. Results: PAE was successful in preventing bleeding and avoid hysterectomy in four cases (group A). Uterine atony and disseminated intravascular coagulation caused failure of PAE requiring hysterectomy in four patients (group B). PAE prevented bleeding post-hysterectomy in the remaining four cases (group C). Technical success (cessation of contrast extravasation on angiography or occlusion of the selected artery) was 100 %. Maternal and foetal mortality and morbidity were 0 %. Conclusions: PAE is a minimal invasive technique that may help to prevent hysterectomy and control PPH in API pregnancies without complications. Embolisation should be performed on an emergency basis. For such cases, an IR team on standby in the obstetrics theatre may be useful to prevent hysterectomy, blood loss and limit morbidity. Key Points: • Endovascular treatment is a validated technique in post-partum haemorrhage. • Abnormal placental implantation is a risk factor for post-partum haemorrhage. • We propose an interventional radiologist standby in the delivery room. © 2015, European Society of Radiology
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