3,681 research outputs found
A high frequency GaAlAs travelling wave electro-optic modulator at 0.82 micrometers
Experimental GaAlAs modulators operating at 0.82 micrometers using a Mach-Zehnder interferometer configuration were designed and fabricated. Coplanar 50 ohm travelling wave microwave electrodes were used to obtain a bandwidth length product of 11.95 GHz-cm. The design, fabrication and dc performance of the GaAlAs travelling wave modulator is presented
Post-Glitch RXTE-PCA Observations of the Vela Pulsar
We report the results of analysis of observations of the Vela Pulsar by PCA
on RXTE. Our data consists of two parts. The first part contains observations
at 1, 4, and 9 days after the glitch in 1996 and has 27000 sec. total exposure
time. The second part of observations were performed three months after this
glitch and have a total exposure time of 93000 sec. We found pulsations in both
sets. The observed spectrum is a power-law with no apparent change in flux or
count rate. The theoretical expectations of increase in flux due to internal
heating after a glitch are smaller than the uncertainty of the observations.Comment: 6 pages, 5 figures in 9 ps/eps files. Accepted for publication in A&A
Main Journa
Tumor detection and elimination by a targeted gallium corrole
Sulfonated gallium(III) corroles are intensely fluorescent macrocyclic compounds that spontaneously assemble with carrier proteins to undergo cell entry. We report in vivo imaging and therapeutic efficacy of a tumor-targeted corrole noncovalently assembled with a heregulin-modified protein directed at the human epidermal growth factor receptor (HER). Systemic delivery of this protein-corrole complex results in tumor accumulation, which can be visualized in vivo owing to intensely red corrole fluorescence. Targeted delivery in vivo leads to tumor cell death while normal tissue is spared. These findings contrast with the effects of doxorubicin, which can elicit cardiac damage during therapy and required direct intratumoral injection to yield similar levels of tumor shrinkage compared with the systemically delivered corrole. The targeted complex ablated tumors at >5 times a lower dose than untargeted systemic doxorubicin, and the corrole did not damage heart tissue. Complexes remained intact in serum and the carrier protein elicited no detectable immunogenicity. The sulfonated gallium(III) corrole functions both for tumor detection and intervention with safety and targeting advantages over standard chemotherapeutic agents
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Activated Bone Marrow-Derived Macrophages Eradicate Alzheimer's-Related Aβ42 Oligomers and Protect Synapses.
Impaired synaptic integrity and function due to accumulation of amyloid β-protein (Aβ42) oligomers is thought to be a major contributor to cognitive decline in Alzheimer's disease (AD). However, the exact role of Aβ42 oligomers in synaptotoxicity and the ability of peripheral innate immune cells to rescue synapses remain poorly understood due to the metastable nature of oligomers. Here, we utilized photo-induced cross-linking to stabilize pure oligomers and study their effects vs. fibrils on synapses and protection by Aβ-phagocytic macrophages. We found that cortical neurons were more susceptible to Aβ42 oligomers than fibrils, triggering additional neuritic arborization retraction, functional alterations (hyperactivity and spike waveform), and loss of VGluT1- and PSD95-excitatory synapses. Co-culturing neurons with bone marrow-derived macrophages protected synapses against Aβ42 fibrils; moreover, immune activation with glatiramer acetate (GA) conferred further protection against oligomers. Mechanisms involved increased Aβ42 removal by macrophages, amplified by GA stimulation: fibrils were largely cleared through intracellular CD36/EEA1+-early endosomal proteolysis, while oligomers were primarily removed via extracellular/MMP-9 enzymatic degradation. In vivo studies in GA-immunized or CD115+-monocyte-grafted APPSWE/PS1ΔE9-transgenic mice followed by pre- and postsynaptic analyses of entorhinal cortex and hippocampal substructures corroborated our in vitro findings of macrophage-mediated synaptic preservation. Together, our data demonstrate that activated macrophages effectively clear Aβ42 oligomers and rescue VGluT1/PSD95 synapses, providing rationale for harnessing macrophages to treat AD
An Analysis of the Development of Modular Building Design Elements to Improve Thermal Performance of a Representative High Rise Residential Estate in the Coastline City of Famagusta, Cyprus
Passive design strategies can reduce heating and cooling demands with integration of more efficient building systems as well as the potential to integrate modular off-site construction technology and its technical systems to offset overall energy consumption. This study evaluates the energy performance of the nationally representative post-war social housing estate in the southeastern Mediterranean island of Cyprus where the weather is subtropical (Csa) and partly semi-arid (Bsh). This study employed a mixed methods research design approach which was based on a thorough field study that consisted of a questionnaire survey conducted with residents of the social housing estate in the hottest summer month of August, to explore the occupants’ thermal sensation votes (TSVs), their habitual adaptive behaviour, and home energy performance concurrently. On-site environmental monitoring was performed, and in-situ measurements of each occupied space were recorded to identify ‘neutral’ adaptive thermal comfort. The selected representative high-rise residential development was modelled using Integrated Environmental Solutions’ Virtual Environment (IES-VE) software, where extensive dynamic thermal simulations have been produced to assess existing energy performance and energy effectiveness of retrofitting strategies. The results demonstrated that a moderate–strong relationship was found between orientation and reasons for thermal discomfort (χ2 = 49,327, p < 0.001, Cramer’s V = 0.405). Individual levels of thermal comfort were not limited to household socio-demographic characteristics, however; environmental factors were also determinants in the development of adaptive thermal-comfort theory. Furthermore, the occupants’ TSVs indicated that in a southeastern Mediterranean climate, 28.5 °C is considered a neutral temperature, and the upper limit of the indoor-air thermal-comfort range is 31.5 °C
An Investigation of Urban Process and Mass Housing Estates Development Through Topographical Formations in Urban Peripheries: A Case Study of Famagusta, Cyprus
Problems in mass housing estates in Famagusta, Cyprus, have been an issue for urban planning and policy interventions for many years. Neighbourhoods were designed featuring modernist residential tower blocks and suburban row houses with insufficient green areas and no consideration of either the climatic features of the built site or of urban planning, regulations or law. This study discusses ongoing, uncontrolled construction trying to change the contemporary urban environment, based on the features of housing and urbanism. It investigates whether the natural landscape and extensions to topography have played decisive roles in the construction of mass housing estate developments and uses of the rural periphery of this city. The study develops a base case of urban transformation models representing the morphological characteristics of buildings from three distinct construction eras (the 1970s, 1990s and 2010s). The information collected is enriched and verified by site surveys. Through three case studies, the types of buildings in each era are analysed and evaluated in relation to a number of environmental factors, including analyses of the different context layers, to ascertain the existing strength of the urban block development configurations as well as to evaluate their shortcomings under the threat of urban sprawl. The findings not only provide ground research for developing urban retrofit scenarios, but also employ sustainable planning tools based on those urban processes
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