Frailty as a Nexus Between the Biology of Aging, Environmental Conditions and Clinical Geriatrics

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Reentry vehicles: evaluation of plasma effects on RF propagation

In the frame of communication technology relevant to the re-entry vehicles, the communication black-out occurring in the presence of plasma is one of the main challenging issues. The re-entry plasma is a complex physical system, where the ionization derives from a shock-wave and non-equilibrium phenomena. As discussed elsewhere, the time scales of plasma dynamics (including its evolution along mission trajectory) and radio wave propagation are well separated so that radio wave propagation is solved at an appropriate number of time "snapshots" in which plasma dynamics is held unchanged and considered as known. In this activity, a consistent effort has been devoted to model the electromagnetic problem. For the involved range of oprative frequencies and expected densities, the plasma can be considered as an inhomogeneous dielectric. The associated electromagnetic problem is solved in two steps, via use of the field equivalence principle. The vehicle-plasma system is substituted by equivalent (Love's) currents on its boundary, radiating in free space; the fields at the boundary are obtained by solving the propagation problem from the antenna, installed on the spacecraft, up to the plasma boundary, through the Eikonal approximation. Radiation is then obtained without further approximations. Unlike other well-known numerical methods (e.g. FEM), this technique is not intrinsecally limited by the electrical dimension of the vehicle-plasma system. This enables to analyze high frequency problems. Since the formation of the re-entry plasma critically depends on the re-entry vehicle shape and kinematics, the related model has been directly derived from the output data of the Computational Fluid Dynamics simulations. All the results of the above mentioned activities have been collected in a new software, the AIPT (Antenna In Plasma Tool, integrated into ADF-EMS Antenna Design Framework Electromagnetic Satellite) able to predict the electromagnetic propagation in the presence of plasm

Reentry vehicles: evaluation of plasma effects on RF propagation

In the frame of communication technology relevant to the re-entry vehicles, the communication black-out occurring in the presence of plasma is one of the main challenging issues. The re-entry plasma is a complex physical system, where the ionization derives from a shock-wave and non-equilibrium phenomena. As discussed elsewhere, the time scales of plasma dynamics (including its evolution along mission trajectory) and radio wave propagation are well separated so that radio wave propagation is solved at an appropriate number of time "snapshots" in which plasma dynamics is held unchanged and considered as known. In this activity, a consistent effort has been devoted to model the electromagnetic problem. For the involved range of oprative frequencies and expected densities, the plasma can be considered as an inhomogeneous dielectric. The associated electromagnetic problem is solved in two steps, via use of the field equivalence principle. The vehicle-plasma system is substituted by equivalent (Love's) currents on its boundary, radiating in free space; the fields at the boundary are obtained by solving the propagation problem from the antenna, installed on the spacecraft, up to the plasma boundary, through the Eikonal approximation. Radiation is then obtained without further approximations. Unlike other well-known numerical methods (e.g. FEM), this technique is not intrinsecally limited by the electrical dimension of the vehicle-plasma system. This enables to analyze high frequency problems. Since the formation of the re-entry plasma critically depends on the re-entry vehicle shape and kinematics, the related model has been directly derived from the output data of the Computational Fluid Dynamics simulations. All the results of the above mentioned activities have been collected in a new software, the AIPT (Antenna In Plasma Tool, integrated into ADF-EMS Antenna Design Framework Electromagnetic Satellite) able to predict the electromagnetic propagation in the presence of plasma

Short- and long-term effect of sulphite on sucrose transport in grapevine (Vitis vinifera L.) leaves. An electrophysiological study

Sucrose is the main carbohydrate translocated in grapevine and its transport may be restricted or inhibited by a number of factors such as the pollutant sulphur dioxide. The present study investigated, for the first time in grapevine, the effects of sulphite on membrane electrical response of sucrose transport in the mesophyll cells. Co-transport of sucrose across the membrane is linked to the free energy in a electrochemical proton gradient. Without the pollutant, electrophysiological traces displayed a metabolic-dependent sucrose electrical response in which an initial depolarization was followed by complete repolarization. In the presence of sulphite, instead, there were different trends depending on time of contact with the tissue of the pollutant. In the short-term, a slower repolarization was observed and in the long-term (after 6 and 12 h) the extent of depolarization (Δ mV) was also reduced. Transmembrane electrical potentials, measured in the presence of sulphite, became significantly (P < 0.01) more positive with increasing time of incubation of the tissue. On the whole, electrophysiological results highlight a direct or indirect effect of the pollutant on the activity of proton pump H+/ATP ase. Since carbohydrate translocation has a central role in the balance between source and sinks in the plant, the results of the research suggest that sulphite can modify the above balance with negative implications for the export of carbohydrate from the leaves

Aging and the burden of multimorbidity: Associations with inflammatory and anabolic hormonal biomarkers

open9siThe InCHIANTI study baseline (1998–2000) was supported as a “targeted project” (ICS110.1/RF97.71) by the Italian Ministry of Health and in part by the U.S. National Institute on Aging (contracts: 263 MD 9164 and 263 MD 821336); the InCHIANTI Follow-up 1 (2001–2003) was funded by the U.S. National Institute on Aging (contracts: N.1-AG-1-1 and N.1-AG-1-2111); the InCHIANTI Follow-ups 2 and 3 studies (2004–2010) were financed by the U.S. National Institute on Aging (contract: N01-AG-5-0002); supported in part by the Intramural Research Program of the National Institute on Aging, National Institutes of Health, Baltimore, MarylandBackground. Multimorbidity increases with aging, but risk factors beyond age are unknown. Objective. To investigate the association of inflammatory and anabolic hormonal biomarkers with presence and prospective development of multimorbidity. Methods. Nine-year longitudinal study of 1018 participants aged 60 years or older (InCHIANTI Study). Multimorbidity was evaluated at baseline and follow-up visits as number of diagnosed diseases from a predefined list of 15 candidate chronic conditions, defined according to standard clinical criteria. Linear mixed models were used to test cross-sectional and longitudinal associations between candidate biomarkers and multimorbidity. Results. At baseline, multimorbidity was significantly higher in older participants (p <. 001) and higher IL-6, IL-1ra, TNF-α receptor II (TNFAR2), and lower dehydroepiandrosterone sulfate were associated with higher number of diseases, independent of age, sex, body mass index, and education. The rate of longitudinal increase in number of chronic diseases was significantly steeper in participants who were older at baseline (p <. 001). In addition, higher baseline IL-6 and steeper increase of IL-6 levels were significantly and independently associated with a steeper increase in multimorbidity over time (p <. 001 and p =. 003, respectively). Sensitivity analyses, performed using 15 different models obtained by removing each of 15 conditions included in the original list of candidate diseases, confirmed that results were not driven by any specific condition. Conclusions. Accumulation of chronic diseases accelerates at older ages and in persons with higher baseline levels and steeper increase over time of IL-6. High IL-6 and increase in IL-6 may serve as early warning sign to better target interventions aimed at reducing the burden of multimorbidity.openFabbri, Elisa; An, Yang; Zoli, Marco; Simonsick, Eleanor M.; Guralnik, Jack M.; Bandinelli, Stefania; Boyd, Cynthia M.; Ferrucci, LuigiFabbri, Elisa; An, Yang; Zoli, Marco; Simonsick, Eleanor M.; Guralnik, Jack M.; Bandinelli, Stefania; Boyd, Cynthia M.; Ferrucci, Luig