126 research outputs found
Solution Map Analysis of a Multiscale Drift-Diffusion Model for Organic Solar Cells
In this article we address the theoretical study of a multiscale
drift-diffusion (DD) model for the description of photoconversion mechanisms in
organic solar cells. The multiscale nature of the formulation is based on the
co-presence of light absorption, conversion and diffusion phenomena that occur
in the three-dimensional material bulk, of charge photoconversion phenomena
that occur at the two-dimensional material interface separating acceptor and
donor material phases, and of charge separation and subsequent charge transport
in each three-dimensional material phase to device terminals that are driven by
drift and diffusion electrical forces. The model accounts for the nonlinear
interaction among four species: excitons, polarons, electrons and holes, and
allows to quantitatively predict the electrical current collected at the device
contacts of the cell. Existence and uniqueness of weak solutions of the DD
system, as well as nonnegativity of all species concentrations, are proved in
the stationary regime via a solution map that is a variant of the Gummel
iteration commonly used in the treatment of the DD model for inorganic
semiconductors. The results are established upon assuming suitable restrictions
on the data and some regularity property on the mixed boundary value problem
for the Poisson equation. The theoretical conclusions are numerically validated
on the simulation of three-dimensional problems characterized by realistic
values of the physical parameters
Measuring Social Well Being in The Big Data Era: Asking or Listening?
The literature on well being measurement seems to suggest that "asking" for a
self-evaluation is the only way to estimate a complete and reliable measure of
well being. At the same time "not asking" is the only way to avoid biased
evaluations due to self-reporting. Here we propose a method for estimating the
welfare perception of a community simply "listening" to the conversations on
Social Network Sites. The Social Well Being Index (SWBI) and its components are
proposed through to an innovative technique of supervised sentiment analysis
called iSA which scales to any language and big data. As main methodological
advantages, this approach can estimate several aspects of social well being
directly from self-declared perceptions, instead of approximating it through
objective (but partial) quantitative variables like GDP; moreover
self-perceptions of welfare are spontaneous and not obtained as answers to
explicit questions that are proved to bias the result. As an application we
evaluate the SWBI in Italy through the period 2012-2015 through the analysis of
more than 143 millions of tweets.Comment: 40 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1512.0156
Biologic targeting in the treatment of inflammatory bowel diseases
The etiology of inflammatory bowel disease (IBD) has not yet been clarified and immunosuppressive agents which nonspecifically reduce inflammation and immunity have been used in the conventional therapies for IBD. Evidence indicates that a dysregulation of mucosal immunity in the gut of IBD causes an overproduction of inflammatory cytokines and trafficking of effector leukocytes into the bowel, thus leading to an uncontrolled intestinal inflammation. Under normal situations, the intestinal mucosa is in a state of âcontrolledâ inflammation regulated by a delicate balance of proinflammatory (tumor necrosis factor [TNF-α], interferon-gamma [IFN-Îł], interleukin-1 [IL-1], IL-6, IL-12 and anti-inflammatory cytokines IL-4, IL-10, IL-11). The mucosal immune system is the central effector of intestinal inflammation and injury, with cytokines playing a central role in modulating inflammation. Cytokines may therefore be a logical target for inflammatory bowel disease therapy using specific cytokine inhibitors. Biotechnology agents targeted against TNF, leukocyte adhesion, Th1 polarization, T cell activation, nuclear factor-kappaB (NF-ÎșB), and other miscellaneous therapies are being evaluated as potential therapies for the treatment of inflammatory bowel disease. In this context, infliximab and adalimumab are currently the only biologic agents approved in Europe for the treatment of inflammatory Crohnâs disease. Other anti-TNF biologic agents have emerged, including CDP571, certolizumab pegol, etanercept, onercept. However, ongoing research continues to generate new biologic agents targeted at specific pathogenic mechanism involved in the inflammatory process. Lymphocyte-endothelial interactions mediated by adhesion molecules are important in leukocyte migration and recruitment to sites of inflammation, and selective blockade of these adhesion molecules is a novel and promising strategy to treat Crohnâs disease. Therapeutics agents to inhibit leukocyte trafficking include natalizumab (approved for use in Crohnâs disease in USA), MLN-02, and ISIS 2302. Other agents being investigated for the treatment of Crohnâs disease include inhibitors of T cell activation, proinflammatory cytokine receptors, Th1 polarization, growth hormone, and growth factors. Agents being investigated for treatment of ulcerative colitis include many of those mentioned above. Controlled clinical trials are currently being conducted, exploring the safety and efficacy of old and new biologic agents, and the search certainly will open new and exciting perspective on the development of therapies for inflammatory bowel disease. A review is made of the main areas of research exploring the mechanisms associated with the pathogenesis of IBD, providing advances in the agents currently in use, and identifying a host of new therapeutic biologic targets
First functionality tests of a 64 x 64 pixel DSSC sensor module connected to the complete ladder readout
The European X-ray Free Electron Laser (XFEL.EU) will provide every 0.1 s a
train of 2700 spatially coherent ultrashort X-ray pulses at 4.5 MHz repetition
rate. The Small Quantum Systems (SQS) instrument and the Spectroscopy and
Coherent Scattering instrument (SCS) operate with soft X-rays between 0.5 keV -
6keV. The DEPFET Sensor with Signal Compression (DSSC) detector is being
developed to meet the requirements set by these two XFEL.EU instruments. The
DSSC imager is a 1 mega-pixel camera able to store up to 800 single-pulse
images per train. The so-called ladder is the basic unit of the DSSC detector.
It is the single unit out of sixteen identical-units composing the
DSSC-megapixel camera, containing all representative electronic components of
the full-size system and allows testing the full electronic chain. Each DSSC
ladder has a focal plane sensor with 128 x 512 pixels. The read-out ASIC
provides full-parallel readout of the sensor pixels. Every read-out channel
contains an amplifier and an analog filter, an up-to 9 bit ADC and the digital
memory. The ASIC amplifier have a double front-end to allow one to use either
DEPFET sensors or Mini-SDD sensors. In the first case, the signal compression
is a characteristic intrinsic of the sensor; in the second case, the
compression is implemented at the first amplification stage. The goal of signal
compression is to meet the requirement of single-photon detection capability
and wide dynamic range. We present the first results of measurements obtained
using a 64 x 64 pixel DEPFET sensor attached to the full final electronic and
data-acquisition chain.Comment: Preprint proceeding for IWORID 2016, 18th International Workshop on
Radiation Imaging Detectors, 3rd-7th July 2016, Barcelona, Spai
Development of a High-Performance Low-Weight Hydraulic Damper for Active Vibration Control of the Main Rotor on HelicoptersâPart 1: Design and Mathematical Model
The helicopter vibrations generated by the main rotor/gearbox assembly are the principal cause of damage to cockpit instruments and discomfort of the crew in terms of cabin noise. The principal path of vibration transmission to the fuselage is through the gearbox rigid support struts. With the aim of reducing these vibrations, this paper presents the design of a low-weight high-performance active damper for vibration control developed by Elettronica Aster S.p.A. The system is intended to replace the conventional struts and is composed of an electro-hydraulic actuator hosted within a compliant structure. This parallel nested structure allows the system to reach a high-power density. A physics-based mathematical model was used as a design digital twin to optimize the performance to meet the strict requirements. The active damper was designed for a reference application of a 15-seat medium-sized twin-engine helicopter. The model was used to perform the tests specified in the acceptance and testing procedure document, showing the compliance with the requirements of the current design. The damper physical realization, test bench design, experimental campaign, and model validation will be presented in Part 2
Development of a High-Performance Low-Weight Hydraulic Damper for Active Vibration Control of the Main Rotor on HelicoptersâPart 2: Preliminary Experimental Validation
Vibrations generated by the main rotor-gearbox assembly in a helicopter are the principal cause of damage to cockpit instruments and crew discomfort in terms of cabin noise. The principal path of vibration transmission to the fuselage is through the gearboxâs rigid support struts. This article is Part 2 of a two-part paper presenting an innovative solution involving the replacement of rigid struts with low-weight, high-performance active dampers for vibration control developed by Elettronica Aster S.p.A. Part 1 provided a comprehensive overview of the system layout obtained through a model-based design process and presented a thorough description of the adopted nonlinear mathematical model. Part 2 focuses on the physical realization of the damper and its dedicated experimental test bench. The mathematical model parameter fitting procedure is presented in detail, as it has been used to help in the definition and optimization of the control schemes and the verification of the expected performance. The experimental results obtained in Part 2 not only demonstrate the compliance of the active damper prototype with the acceptance tests outlined in the ATP but also provide compelling evidence reinforcing the promise of the presented solution for effective vibration reduction
Rescheduling rehabilitation sessions with answer set programming
The rehabilitation scheduling process consists of planning rehabilitation physiotherapy sessions for patients, by assigning proper operators to them in a certain time slot of a given day, taking into account several requirements and optimizations, e.g. patientâs preferences and operatorâs work balancing. Being able to efficiently solve such problem is of upmost importance, in particular as a consequence of the COVID-19 pandemic that significantly increased rehabilitationâs needs. The problem has been recently successfully solved via a two-phase solution based on answer set programming (ASP). In this paper, we focus on the problem of rescheduling the rehabilitation sessions, which comes into play when the original schedule cannot be implemented, for reasons that involve the unavailability of operators and/or the absence of patients. We provide rescheduling solutions based on ASP for both phases, considering different scenarios. Results of experiments performed on real benchmarks, provided by ICS Maugeri, show that also the rescheduling problem can be solved in a satisfactory way. Finally, we present a web application that supports the usage of our solution
Telematic integration of health data: the INTESA project
Following an approach based on the methods of basic research, the INTESA project has developed a complete architecture of health information system, capable to guarantee a smart and safe storing of the essential information, an effective and personalized retrieval of data, and some innovative models to compare the results of clinical and medical activities of all the "actors" of the health care process. Together with other metropolitan repositories based on HL7 messages and applications able to examine the data stored, the developed archive will contribute to keep a check on every citizen's health history, clinical examinations and cure therapies, but, above all, it will allow to verify the efficacy and efficiency of the health care processes related to particular pathologies.Non present
8-Hydroxy-2-Deoxyguanosine Levels and Cardiovascular Disease: A Systematic Review and Meta-Analysis of the Literature
Significance: 8-Hydroxy-2-deoxyguanosine (8-OHdG) is generated after the repair of ROS-mediated DNA damages and, thus, is one of the most widely recognized biomarkers of oxidative damage of DNA because guanosine is the most oxidized among the DNA nucleobases. In several pathological conditions, high urinary levels of oxidized DNA-derived metabolites have been reported (e.g., cancer, atherosclerosis, hypertension, and diabetes). Recent Advances: Even if published studies have shown that DNA damage is significantly associated with the development of atherosclerosis, the exact role of this damage in the onset and progression of this pathology is not fully understood, and the association of oxidative damage to DNA with cardiovascular disease (CVD) still needs to be more extensively investigated. We performed a meta-analysis of the literature to investigate the association among 8-OHdG levels and CVD. Critical Issues: Fourteen studies (810 CVD patients and 1106 controls) were included in the analysis. We found that CVD patients showed higher 8-OHdG levels than controls (SMD: 1.04, 95%CI: 0.61, 1.47, p < 0.001, I2 = 94%, p < 0.001). The difference was confirmed both in studies in which 8-OHdG levels were assessed in urine (MD: 4.43, 95%CI: 1.71, 7.15, p = 0.001) and in blood samples (MD: 1.42, 95%CI: 0.64, 2.21, p = 0.0004). Meta-regression models showed that age, hypertension, and male gender significantly impacted on the difference in 8-OHdG levels among CVD patients and controls. Future Directions: 8-OHdG levels are higher in patients with CVD than in controls. However, larger prospective studies are needed to test 8-OHdG as a predictor of CVD. Antioxid. Redox Signal. 24, 548-555
Solving rehabilitation scheduling problems via a two-phase ASP approach
A core part of the rehabilitation scheduling process consists of planning rehabilitation physiotherapy sessions for patients, by assigning proper operators to them in a certain time slot of a given day, taking into account several legal, medical and ethical requirements and optimizations, e.g., patientâs preferences and operatorâs work balancing. Being able to efficiently solve such problem is of upmost importance, in particular after the COVID-19 pandemic that significantly increased rehabilitationâs needs.
In this paper, we present a two-phase solution to rehabilitation scheduling based on Answer Set Programming, which proved to be an effective tool for solving practical scheduling problems. We first present a general encoding, and then add domain specific optimizations. Results of experiments performed on both synthetic and real benchmarks, the latter provided by ICS Maugeri, show the effectiveness of our solution as well as the impact of our domain specific optimization
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