Extending ballistic graphene FET lumped element models to diffusive devices

In this work, a modified, lumped element graphene field effect device model is presented. The model is based on the "Top-of-the-barrier" approach which is usually valid only for ballistic graphene nanotransistors. Proper modifications are introduced to extend the model's validity so that it accurately describes both ballistic and diffusive graphene devices. The model is compared to data already presented in the literature. It is shown that a good agreement is obtained for both nano-sized and large area graphene based channels. Accurate prediction of drain current and transconductance for both cases is obtained

Nano-antenna array for high efficiency sunlight harvesting

none5noSolar rectennas are promising devices for energy harvesting. Capability of rectennas to convert incident light into useful energy depends on the antenna efficiency, that is the ratio between the power transferred to the load vs the incoming power. In this work, we first emphasize that for the efficiency to be calculated accurately, antennas need to be treated as receiving devices, not as transmitting ones. Then, we propose an arrangement of antennas that differs from those published so far in three respects: (1) the proposed arrangement is formed by an array of nano-antennas with sub-wavelength inter-element spacing, (2) it comprises a reflecting mirror, and (3) it allows for dual polarization operation. Through numerical simulations, we show that the small lattice pitch we use is responsible for frequency flattening of the lattice impedance over the whole solar spectrum, eventually allowing for excellent matching with the antennas’ loads. Also, the small pitch allows for a smooth dependence of the receiving efficiency on the angle of incidence of sunlight. Finally, we show numerically that the reflecting mirror also allows for an almost complete cancellation of light scattered by the receiving antennas. The final result is a polarization insensitive receiving theoretical efficiency larger than 70% over the whole 300-3000 nm spectral range, with a less than 10% energy wasting due to back-scattering of sunlight.openMidrio M.; Pierantoni L.; Boscolo S.; Truccolo D.; Mencarelli D.Midrio, M.; Pierantoni, L.; Boscolo, S.; Truccolo, D.; Mencarelli, D

Rubbing effects on the structural and optical properties of poly(3­hexylthiophene) films

International audienc

D2 or non D2-lymphadenectomy in gastric cancer

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Postharvest Ozone Fumigation of Grapes (cv Sangiovese) Differently Affects Volatile Organic Compounds and Polyphenol Profiles of Berries and Wine

Consumers are more and more oriented towards the purchase of safer food and beverages, which is pushing the wine sector to find alternatives to the use of sulfur dioxide. Ozone (O3) is already applied in the wine industry to produce sulfur dioxide-free wines through the patented method Purovino®. The aim of this two-year study was that of evaluating whether the postharvest treatment of grapes with ozone affects volatile organic compounds (VOCs) and polyphenol profile in berries, and in turn, wine composition. Grape bunches (Vitis vinifera L.) of cv Sangiovese were fumigated overnight with gaseous ozone (max 20 g·h−1 with 6% w.w−1 of ozone) in a cold room at 4°C (±0.5). After treatment, grapes were processed into wine. In grapes, ozone treatments increased total polyphenol and flavonoid content and upregulated specific genes (phenylalanine ammonia lyase, VvPAL, flavanol synthase 1, and VvFLS1) involved in polyphenol biosynthesis. Wine obtained from ozone-treated grapes had higher flavanol content than the control. Fumigation only slightly affected the different VOC classes of grapes and wine, including aroma compounds derived from the lipoxygenase (LOX) pathway. Although a season-dependent effect was observed, results showed that postharvest ozone treatments applied to avoid the use of sulfur dioxide introduced limited but, in general, positive modifications to grape and wine composition. This information provides assurance to winemakers that the maintenance of wine quality and typicity will be guaranteed when using ozone treatments

Administration of aspirin tablets using a novel gel-based swallowing aid: an open-label randomised controlled cross-over trial

Introduction To ease administration of medicines to people with dysphagia we developed and patented a gel formulation within which whole tablets could be inserted. The aim was to determine whether the gel would affect bioequivalence of uncoated aspirin tablet. Method A gel containing gelatin, hydroxypropylmethylcellulose, citric acid, potassium sorbate and water was developed to maintain structure on tablet insertion and increase saliva production to lubricate the swallow. In an open-label cross-over trial 12 healthy male volunteers were administered a 300 mg uncoated aspirin tablet with and without gel with a 7-day washout period. Blood salicylate levels, platelet activity and patient satisfaction were measured over 2 hours. Analysis was based on a random effects cross-over model. Results The estimated mean ratio (90% CI) of effect on salicylate levels when comparing administration with and without gel was 0.77 (90% CI 0.40 to 1.47) for amount absorbed and 0.76 (90% CI 0.44 to 1.31) and on total ASP-arachidonic acid platelet activity 1.16 (90% CI 0.88 to 1.53) and maximum ASP arachidonic platelet activity 0.98 (90% CI 0.79 to 1.22). These results are outside of the range allowable for the assumption of bioequivalence. Participants rated the taste of aspirin tablets significantly better when encapsulated in the gel (p<0.05). Discussion We cannot assume that uncoated aspirin administration with and without gel is bioequivalent. Administration with gel resulted in reduced salicylate levels and therefore increased platelet function. Further research is required to determine the exact reason for this result. The results bring into question current processes for providing marketing authorisation for medical devices which are designed to aid swallowing

Multidisciplinarity in Transition Pathways for Patients With Kidney Disease: The Current State of Play

In the field of medical care, successful transition from pediatric-centered to adult-oriented healthcare can provide a sense of continuity in the development of youth, and prepare them to accept responsibility for and manage their own chronic kidney condition in complete autonomy. The so-called transition process requires the presence of some basic aspects: a multidisciplinary team, which acts as a bridge between child and adult services; a comprehensive clinical, cognitive, psychological, and social change for the young people; the involvement of family and caregivers. Within the framework of transition and chronicity during the developmental age, we selected international papers explaining models which agreed on some important steps in the transition process, although many differences can be observed between different countries. In fact, in Europe, the situation appears to be heterogeneous as regards certain aspects: the written transition plan, the educational programmes, the timing of transfer to adult services, the presence of a transition coordinator, a dedicated off-site transition clinic. We then analyzed some studies focusing on patients with renal diseases, including the first to contain a standardized protocol for transition which was launched recently in the USA, and which seems to have already achieved important positive, although limited, results. In Italy, the issue of transition is still in its infancy, however important efforts in the management of chronic kidney disease have already been initiated in some regions, including Emila Romagna, which gives us hope for the future of many young people

Graphene-based Electronically Tuneable Microstrip Attenuator

This paper presents the design of a graphene-based electronically tuneable microstrip attenuator operating at a frequency of 5 GHz. The use of graphene as a variable resistor is discussed and the modelling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics can range from being a fairly good conductor to a highly lossy material, depending on the applied voltage. By applying the proper voltage through two high-impedance bias lines, the surface resistivity of graphene can be modified, thereby changing the insertion loss of the microstrip attenuator