529 research outputs found
Sensor Integrated Metal Dielectric Filters for Solar-Blind Silicon Ultraviolet Detectors
A filter for electromagnetic radiation including one or more dielectric spacer regions and one or more reflective regions integrated on a semiconductor substrate, the semiconductor substrate including a semiconductor photodetector, such that the filter transmits ultraviolet radiation to the semiconductor photodetector, the ultraviolet radiation having a range of wavelengths, and the filter suppresses transmission of electromagnetic radiation, having wavelengths outside the range of wavelengths, to the semiconductor photodetector
Activity-Dependent mRNA Splicing Controls ER Export and Synaptic Delivery of NMDA Receptors
AbstractActivity-dependent targeting of NMDA receptors (NMDARs) is a key feature of synapse formation and plasticity. Although mechanisms for rapid trafficking of glutamate receptors have been identified, the molecular events underlying chronic accumulation or loss of synaptic NMDARs have remained unclear. Here we demonstrate that activity controls NMDAR synaptic accumulation by regulating forward trafficking at the endoplasmic reticulum (ER). ER export is accelerated by the alternatively spliced C2′ domain of the NR1 subunit and slowed by the C2 splice cassette. This mRNA splicing event at the C2/C2′ site is activity dependent, with C2′ variants predominating upon activity blockade and C2 variants abundant with increased activity. The switch to C2′ accelerates NMDAR forward trafficking by enhancing recruitment of nascent NMDARs to ER exit sites via binding of a divaline motif within C2′ to COPII coats. These results define a novel pathway underlying activity-dependent targeting of glutamate receptors, providing an unexpected mechanistic link between activity, mRNA splicing, and membrane trafficking during excitatory synapse modification
Polarized Secretory Trafficking Directs Cargo for Asymmetric Dendrite Growth and Morphogenesis
SummaryProper growth of dendrites is critical to the formation of neuronal circuits, but the cellular machinery that directs the addition of membrane components to generate dendritic architecture remains obscure. Here, we demonstrate that post-Golgi membrane trafficking is polarized toward longer dendrites of hippocampal pyramidal neurons in vitro and toward apical dendrites in vivo. Small Golgi outposts partition selectively into longer dendrites and are excluded from axons. In dendrites, Golgi outposts concentrate at branchpoints where they engage in post-Golgi trafficking. Within the cell body, the Golgi apparatus orients toward the longest dendrite, and this Golgi polarity precedes asymmetric dendrite growth. Manipulations that selectively block post-Golgi trafficking halt dendrite growth in developing neurons and cause a shrinkage of dendrites in mature pyramidal neurons. Further, disruption of Golgi polarity produces neurons with symmetric dendritic arbors lacking a single longest principal dendrite. These results define a novel polarized organization of neuronal secretory trafficking and demonstrate a mechanistic link between directed membrane trafficking and asymmetric dendrite growth
High efficiency CCD detectors at UV wavelengths
The Faint Intergalactic Redshifted Emission Balloon (FIREBall) is a NASA/CNES balloon-borne ultraviolet
multi-object spectrograph designed to observe the diffuse gas around galaxies (the circumgalactic medium) via
line emission redshifted to ~ 205 nm. FIREBall uses a ultraviolet-optimized delta doped e2v CCD201 with a
custom designed high efficiency five layer anti-re
ection coating. This combination achieves very high quantum
efficiency (QE) and photon-counting capability, a first for a CCD detector in this wavelength range. We also present new work on red blocking mirror coatings to reduce red leak
Materials and process development for the fabrication of far ultraviolet device-integrated filters for visible-blind Si sensors
In this work, we show that the direct integration of ultraviolet metal-dielectric filters with Si sensors can improve throughput over external filter approaches, and yield devices with UV quantum efficiencies greater than 50%, with rejection ratios of visible light greater than 10^3. In order to achieve these efficiencies, two-dimensional doping methods are used to increase the UV sensitivity of back-illuminated Si sensors. Integrated filters are then deposited by a combination of Al evaporation and atomic layer deposition of dielectric spacer layers. At far UV wavelengths these filters require the use of non-absorbing dielectrics, and we have pursued the development of new atomic layer deposition processes for metal fluorides materials of MgF_2, AlF_3 and LiF. The performance of the complete multilayer filters on Si photodiodes and CCD imaging sensors, and the design and fabrication challenges associated with this development are demonstrated. This includes the continued development of deep diffused silicon avalanche photodiodes designed to detect the fast 220 nm emission component of barium fluoride scintillation crystals, while optically rejecting a slower component at 300 nm
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The Survival Benefits of Antiretroviral Therapy in South Africa
Background. We sought to quantify the survival benefits attributable to antiretroviral therapy (ART) in South Africa since 2004. Methods. We used the Cost-Effectiveness of Preventing AIDS Complications–International model (CEPAC) to simulate 8 cohorts of human immunodeficiency virus (HIV)–infected patients initiating ART each year during 2004–2011. Model inputs included cohort-specific mean CD4+ T-cell count at ART initiation (112–178 cells/µL), 24-week ART suppressive efficacy (78%), second-line ART availability (2.4% of ART recipients), and cohort-specific 36-month retention rate (55%–71%). CEPAC simulated survival twice for each cohort, once with and once without ART. The sum of the products of per capita survival differences and the total numbers of persons initiating ART for each cohort yielded the total survival benefits. Results. Lifetime per capita survival benefits ranged from 9.3 to 10.2 life-years across the 8 cohorts. Total estimated population lifetime survival benefit for all persons starting ART during 2004–2011 was 21.7 million life-years, of which 2.8 million life-years (12.7%) had been realized by December 2012. By 2030, benefits reached 17.9 million life-years under current policies, 21.7 million life-years with universal second-line ART, 23.3 million life-years with increased linkage to care of eligible untreated patients, and 28.0 million life-years with both linkage to care and universal second-line ART. Conclusions. We found dramatic past and potential future survival benefits attributable to ART, justifying international support of ART rollout in South Africa
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A customizable microfluidic platform for medium-throughput modeling of neuromuscular circuits
Neuromuscular circuits (NMCs) are vital for voluntary movement, and effective models of NMCs are needed to understand the pathogenesis of, as well as to identify effective treatments for, multiple diseases, including Duchenne's muscular dystrophy and amyotrophic lateral sclerosis. Microfluidics are ideal for recapitulating the central and peripheral compartments of NMCs, but myotubes often detach before functional NMCs are formed. In addition, microfluidic systems are often limited to a single experimental unit, which significantly limits their application in disease modeling and drug discovery. Here, we developed a microfluidic platform (MFP) containing over 100 experimental units, making it suitable for medium-throughput applications. To overcome detachment, we incorporated a reactive polymer surface allowing customization of the environment to culture different cell types. Using this approach, we identified conditions that enable long-term co-culture of human motor neurons and myotubes differentiated from human induced pluripotent stem cells inside our MFP. Optogenetics demonstrated the formation of functional NMCs. Furthermore, we developed a novel application of the rabies tracing assay to efficiently identify NMCs in our MFP. Therefore, our MFP enables large-scale generation and quantification of functional NMCs for disease modeling and pharmacological drug targeting. © 2019 The Author
Book Reviews
Catherine Stonehouse and Scottie MayListening to Children on the Spiritual Journey: Guidance for Those Who Teach and Nurture2010. Grand Rapids, MI: Baker AcademicReviewed by Desiree Segura-April
Dyron B. DaughrityThe Changing World of Christianity: The Global History of a Borderless Religion2010. New York: Peter LangReviewed by Meesaeng Lee Choi
Derek TidballThe Message of Holiness: Restoring God\u27s Masterpiece2010. Downers Grove, IL Inter-Varsity, PressReviewed by Joseph R. Dongell
Accordance. Scholars CollectionDVD-ROM and CD-ROM, version 82008. OakTree Software, Inc.Reviewed by Michael D. Matlock and Jason R. Jackson
Paul L. Gavrilyuk, Douglas M. Koskela, Jason E. Vickers, Eds.Immersed in the Life of God: The Healing Resources of the Christian Faith2008. Grand Rapids: William B. Eerdmans Publishing Co.Reviewed by Stephen Seamands
Thomas Jay OordThe Nature of Love: A TheologySt. Louis, MO: Chalice Press, 2010Reviewed by Wm. Andrew Schwartz
James R. PaytonGetting the Reformation Wrong. Correcting some MisunderstandingsDowners Grove: InterVarsity Press, 2010, 240 pages, $23Reviewed by Ben Witherington
Kenneth Cain KinghornThe Story of Asbury Theological Seminary2010. Published by Emeth PressReviewed by Laurence W. Woo
Advanced imaging capabilities by incorporating plasmonics and metamaterials in detectors
Ultraviolet detection is often required to be made in the presence of a strong background of solar radiation which needs to be suppressed, but materials limitations at these wavelengths can impact both filter and sensor performance. In this work, we explore the use of 1D photonic bandgap structures integrated directly onto a Si sensor that can operate with solar blindness. These filters take advantage of the improved admittance with silicon to significantly improve throughput over conventional stand-alone bandpass filter elements. At far ultraviolet wavelengths these filters require the use of non-absorbing dielectrics such as the metal fluoride materials of MgF_2, AlF_3 and LiF. The latest performance of these 1D multilayer filters on Si photodiodes and CCD imaging sensors is demonstrated. We have also extended these 1D structures to more complex multilayers guided by the design concepts of metamaterials and metatronics, and to 2D patterned plasmonic hole array filters fabricated in aluminum. The performance of sensors and test filter structures is presented with an emphasis on UV throughput
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