1,245 research outputs found
Nearly Massless Electrons in the Silicon Interface with a Metal Film
We demonstrate the realization of nearly massless electrons in the most
widely used device material, silicon, at the interface with a metal film. Using
angle-resolved photoemission, we found that the surface band of a monolayer
lead film drives a hole band of the Si inversion layer formed at the interface
with the film to have nearly linear dispersion with an effective mass about 20
times lighter than bulk Si and comparable to graphene. The reduction of mass
can be accounted for by repulsive interaction between neighboring bands of the
metal film and Si substrate. Our result suggests a promising way to take
advantage of massless carriers in silicon-based thin-film devices, which can
also be applied for various other semiconductor devices.Comment: 4 pages, 4 figures, accepted for publication in Physical Review
Letter
CIB1 protects against MPTP-induced neurotoxicity through inhibiting ASK1.
Calcium and integrin binding protein 1 (CIB1) is a calcium-binding protein that was initially identified as a binding partner of platelet integrin αIIb. Although CIB1 has been shown to interact with multiple proteins, its biological function in the brain remains unclear. Here, we show that CIB1 negatively regulates degeneration of dopaminergic neurons in a mouse model of Parkinson\u27s disease using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Genetic deficiency of the CIB1 gene enhances MPTP-induced neurotoxicity in dopaminergic neurons in CIB1(-/-) mice. Furthermore, RNAi-mediated depletion of CIB1 in primary dopaminergic neurons potentiated 1-methyl-4-phenyl pyrinidium (MPP(+))-induced neuronal death. CIB1 physically associated with apoptosis signal-regulating kinase 1 (ASK1) and thereby inhibited the MPP(+)-induced stimulation of the ASK1-mediated signaling cascade. These findings suggest that CIB1 plays a protective role in MPTP/MPP(+)-induced neurotoxicity by blocking ASK1-mediated signaling
만성 중심장액맥락망막증의 절반 용량의 광역학 치료와 저시간 광역학치료의 비교 Comparative Study of Subjects with Chronic Central Serous Chorioretinopathy Undergoing Half-Dose or Time-Reduced Photodynamic Therapy
Purpose: To compare the clinical outcomes of reduced fluence (time-reduced) photodynamic therapy (PDT) and half-dose PDT in treating chronic central serous chorioretinopathy (CSC). Methods: Medical records of patients who underwent half-dose or reduced fluence PDT for chronic CSC were reviewed. The clinical outcomes of 34 eyes that underwent half-dose PDT and 39 eyes that underwent reduced fluence PDT were compared. Results: Six months after treatment, complete absorption of subretinal fluid was observed in 29 of 34 eyes (85.3%) in the half-dose PDT group and 36 of 39 eyes (92.3%) in the reduced fluence PDT group (p = 0.46). Twenty-one of 34 (61.8%) eyes in the half-dose PDT group and 27 of 39 (69.2%) eyes in the reduced fluence PDT group achieved visual improvement of more than one line in the Snellen chart (p = 0.62). Focal retinal pigment epithelium degeneration after treatment was noted in 7 of 27 eyes (25.9%) in the half-dose PDT group and 10 of 30 (33.3%) eyes in the reduced fluence PDT group (p = 0.58). Conclusions: Reduced fluence PDT showed a favorable outcome, similar to that of half-dose PDT, in treating chronic CSC. Because of its convenient preparation and application, reduced fluence (low-fluence) PDT might be an alternative treatment modality in treating chronic CSC
Re-evaluation of the optimum dietary protein level for maximum growth of juvenile barred knifejaw Oplegnathus fasciatus reared in cages
Abstract We determined the optimum dietary protein level in juvenile barred knifejaw Oplegnathus fasciatus in cages. Five semi-purified isocaloric diets were formulated with white fish meal and casein-based diets to contain 35, 40, 45, 50, and 60 % crude protein (CP). Fish with an initial body weight of 7.1 ± 0.06 g (mean ± SD) were randomly distributed into 15 net cages (each size: 60 cm × 40 cm × 90 cm, W × L × H) as groups of 20 fish in triplicates. The fish were fed at apparent satiation level twice a day. After 8 weeks of feeding, the weight gain (WG) of fish fed 45, 50, and 60 % CP diets were significantly higher than those of fish fed 35 and 40 % CP diets. However, there were no significant differences in WG among fish fed 45, 50, and 60 % CP diets. Generally, feed efficiency (FE) and specific growth rate (SGR) showed a similar trend as WG. However, the protein efficiency ratio (PER) was inversely related to dietary protein levels. Energy retention efficiency increased with the increase of dietary protein levels by protein sparing from non-protein energy sources. Blood hematocrit content was not affected by dietary protein levels. However, a significantly lower amount of hemoglobin was found in fish fed 35 % CP than in fish fed 40, 45, 50, and 60 % CP diets. Fish fed 60 % CP showed the lowest survival rate than the fish fed 35, 40, 45, and 50 % CP diets. Broken-line analysis of WG showed the optimum dietary protein level was 45.2 % with 18.8 kJ/g diet for juvenile barred knifejaw. This study has potential implication for the successful cage culture of barred knifejaw
Deep Learning Guided Autonomous Retinal Surgery using a Robotic Arm, Microscopy, and iOCT Imaging
Recent technological advancements in retinal surgery has led to the modern
operating room consisting of a surgical robot, microscope, and intraoperative
optical coherence tomography (iOCT). The integration of these tools raises the
fundamental question of how to effectively combine them to enable surgical
autonomy. In this work, we address this question by developing a unified
framework that enables real-time autonomous surgical workflows utilizing the
aforementioned devices. To achieve this, we make the following contributions:
(1) we develop a novel imaging system that integrates microscopy and iOCT in
real-time, accomplished by dynamically tracking the surgical instrument via a
small iOCT scanning region (e.g. B-scan), which was not previously possible;
(2) implementing various convolutional neural networks (CNN) that automatically
segment and detect task-relevant information for surgical autonomy; (3)
enabling surgeons to intuitively select goal waypoints within both the
microscope and iOCT views through simple mouse-click interactions; (4)
integrating model predictive control (MPC) for real-time trajectory generation
that respects kinematic constraints to ensure patient safety. We show the
utility of our system by tackling subretinal injection (SI), a challenging
procedure that involves inserting a microneedle below the retinal tissue for
targeted drug delivery, a task surgeons find challenging due to requiring
tens-of-micrometers of accuracy and precise depth perception. We validate our
system by conducting 30 successful SI trials on pig eyes, achieving needle
insertion accuracy of to various subretinal goals and
duration of seconds. Preliminary comparisons to a human operator
performing SI in robot-assisted mode highlight the enhanced safety of our
system.Comment: pending submission to a journa
Artificial External Glottic Device for Passive Lung Insufflation
PURPOSE: For patients with neuromuscular disease, air stacking, which inflates the lungs to deep volumes, is important for many reasons. However, neuromuscular patients with severe glottic dysfunction or indwelling tracheostomy tubes cannot air stack effectively. For these patients, we developed a device that permits deep lung insufflations substituting for glottic function.
MATERIALS AND METHODS: Thirty- seven patients with bulbar-innervated muscle weakness and/or tracheostomies were recruited. Twenty-three had amyotrophic lateral sclerosis, and 14 were tetraplegic patients due to cervical spinal cord injury. An artificial external glottic device (AEGD) was used to permit passive deep lung insufflation. In order to confirm the utility of AEGD, vital capacity, maximum insufflation capacity (MIC), and lung insufflation capacity (LIC) with AEGD (LICA) were measured.
RESULTS: For 30 patients, MICs were initially zero. However, with the use of the AEGD, LICA was measurable for all patients. The mean LICA was 1,622.7±526.8 mL. Although MIC was measurable for the remaining 7 patients without utilizing the AEGD, it was significantly less than LICA, which was 1,084.3±259.9 mL and 1,862.9±248 mL, respectively (p<0.05).
CONCLUSION: The AEGD permits lung insufflation by providing deeper lung volumes than possible by air stacking.ope
Macrophages but not Astrocytes Harbor HIV DNA in the Brains of HIV-1-Infected Aviremic Individuals on Suppressive Antiretroviral Therapy
The question of whether the human brain is an anatomical site of persistent HIV-1 infection during suppressive antiretroviral therapy (ART) is critical, but remains unanswered. The presence of virus in the brains of HIV patients whose viral load is effectively suppressed would demonstrate not only the potential for CNS to act as an anatomical HIV reservoir, but also the urgent need to understand the factors contributing to persistent HIV behind the blood-brain barrier. Here, we investigated for the first time the presence of cells harboring HIV DNA and RNA in the brains from subjects with undetectable plasma viral load and sustained viral suppression, as identified by the National NeuroAIDS Tissue Consortium. Using new, highly sensitive in situ hybridization techniques, RNAscope and DNAscope, in combination with immunohistochemistry, we were able to detect HIV-1 in the brains of all virally suppressed cases and found that brain macrophages and microglia, but not astrocytes, were the cells harboring HIV DNA in the brain. This study demonstrated that HIV reservoirs persist in brain macrophages/microglia during suppressive ART, which cure/treatment strategies will need to focus on targeting
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