10,700 research outputs found
Combined SIRT3 and SIRT5 deletion is associated with inner retinal dysfunction in a mouse model of type 1 diabetes
Abstract Diabetic retinopathy (DR) is a major cause of blindness in working adults in the industrialized world. In addition to vision loss caused by macular edema and pathological angiogenesis, DR patients often exhibit neuronal dysfunction on electrophysiological testing, suggesting that there may be an independent neuronal phase of disease that precedes vascular disease. Given the tremendous metabolic requirements of the retina and photoreceptors in particular, we hypothesized that derangements in metabolic regulation may accelerate retinal dysfunction in diabetes. As such, we induced hyperglycemia with streptozotocin in mice with monoallelic Nampt deletion from rod photoreceptors, mice lacking SIRT3, and mice lacking SIRT5 and tested multiple components of retinal function with electroretinography. None of these mice exhibited accelerated retinal dysfunction after induction of hyperglycemia, consistent with normal-appearing retinal morphology in hyperglycemic Sirt3 −/− or Sirt5 −/− mice. However, mice lacking both SIRT3 and SIRT5 (Sirt3 −/− Sirt5 −/− mice) exhibited significant evidence of inner retinal dysfunction after induction of hyperglycemia compared to hyperglycemic littermate controls, although this dysfunction was not accompanied by gross morphological changes in the retina. These results suggest that SIRT3 and SIRT5 may be involved in regulating neuronal dysfunction in DR and provide a foundation for future studies investigating sirtuin-based therapies
An artificial intelligence-based structural health monitoring system for aging aircraft
To reduce operating expenses, airlines are now using the existing fleets of commercial aircraft well beyond their originally anticipated service lives. The repair and maintenance of these 'aging aircraft' has therefore become a critical safety issue, both to the airlines and the Federal Aviation Administration. This paper presents the results of an innovative research program to develop a structural monitoring system that will be used to evaluate the integrity of in-service aerospace structural components. Currently in the final phase of its development, this monitoring system will indicate when repair or maintenance of a damaged structural component is necessary
High Thermoelectric Figure of Merit by Resonant Dopant in Half-Heusler Alloys
Half-Heusler alloys have been one of the benchmark high temperature
thermoelectric materials owing to their thermal stability and promising figure
of merit ZT. Simonson et al. early showed that small amounts of vanadium doped
in Hf0.75Zr0.25NiSn enhanced the Seebeck coefficient and correlated the change
with the increased density of states near the Fermi level. We herein report a
systematic study on the role of vanadium (V), niobium (Nb), and tantalum (Ta)
as prospective resonant dopants in enhancing the ZT of n-type half-Heusler
alloys based on Hf0.6Zr0.4NiSn0.995Sb0.005. The V doping was found to increase
the Seebeck coefficient in the temperature range 300-1000 K, consistent with a
resonant doping scheme. In contrast, Nb and Ta act as normal n-type dopants, as
evident by the systematic decrease in electrical resistivity and Seebeck
coefficient. The combination of enhanced Seebeck coefficient due to the
presence of V resonant states and the reduced thermal conductivity has led to a
state-of-the-art ZT of 1.3 near 850 K in n-type
(Hf0.6Zr0.4)0.99V0.01NiSn0.995Sb0.005 alloys.Comment: Submitted to AIP Advance
An integrated capacitance bridge for high-resolution, wide temperature range quantum capacitance measurements
We have developed a highly-sensitive integrated capacitance bridge for
quantum capacitance measurements. Our bridge, based on a GaAs HEMT amplifier,
delivers attofarad (aF) resolution using a small AC excitation at or below kT
over a broad temperature range (4K-300K). We have achieved a resolution at room
temperature of 10aF per root Hz for a 10mV AC excitation at 17.5 kHz, with
improved resolution at cryogenic temperatures, for the same excitation
amplitude. We demonstrate the performance of our capacitance bridge by
measuring the quantum capacitance of top-gated graphene devices and comparing
against results obtained with the highest resolution commercially-available
capacitance measurement bridge. Under identical test conditions, our bridge
exceeds the resolution of the commercial tool by up to several orders of
magnitude.Comment: (1)AH and JAS contributed equally to this work. 6 pages, 5 figure
Dispositional Authenticity, Internalized Homonegativity, and Relationship Quality in Same-Gender Couples : An Actor-Partner Interdependence Moderation Model
Additional information Funding The authors received no funding for this study.Peer reviewedPublisher PD
Manager\u27s Perspectives on the Provision of Healthy Meals in Resort Hotels
This research aimed to understand hotel managers’ attitudes toward the provision of healthy meals. The study deployed a mailing survey to assess the managers’ perceptions. A closed-ended questionnaire was developed evaluating the role of healthy food choices in Mediterranean resort hotels. The findings showed that (1) atmosphere in the restaurant, (2) appealing display of food, and (3) eating habits and lifestyle were more important than personal health when selecting a meal. In addition, this study suggested that the managers were not ready to promote healthy eating because their customers would have been critical of this new service concep
Calorimetric and magnetic study for NiMnIn and relative cooling power in paramagnetic inverse magnetocaloric systems
The non-stoichiometric Heusler alloy NiMnIn undergoes a
martensitic phase transformation in the vicinity of 345 K, with the high
temperature austenite phase exhibiting paramagnetic rather than ferromagnetic
behavior, as shown in similar alloys with lower-temperature transformations.
Suitably prepared samples are shown to exhibit a sharp transformation, a
relatively small thermal hysteresis, and a large field-induced entropy change.
We analyzed the magnetocaloric behavior both through magnetization and direct
field-dependent calorimetry measurements. For measurements passing through the
first-order transformation, an improved method for heat-pulse relaxation
calorimetry was designed. The results provide a firm basis for the analytic
evaluation of field-induced entropy changes in related materials. An analysis
of the relative cooling power (RCP), based on the integrated field-induced
entropy change and magnetizing behavior of the Mn spin system with
ferromagnetic correlations, shows that a significant RCP may be obtained in
these materials by tuning the magnetic and structural transformation
temperatures through minor compositional changes or local order changes
Betting Big on CPEC
With the launch of the China- Pakistan Economic Corridor (CPEC), one fundamental question to ask is if this ambitious project will transform Pakistan and boost China’s ambitious Belt and Road Initiative (BRI). In this article, the authors assess the potential and prospect of CPEC in terms of its various opportunities and constraints and examine the economic potentials and social impacts of CPEC from the Pakistani national perspective using a subnational and local lens as well as from the Chinese vantage point and draw the broad implications of this two-sided analysis of CPEC toward a preliminary policy oriented conclusion
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