610 research outputs found
The COST IRACON Geometry-based Stochastic Channel Model for Vehicle-to-Vehicle Communication in Intersections
Vehicle-to-vehicle (V2V) wireless communications can improve traffic safety
at road intersections and enable congestion avoidance. However, detailed
knowledge about the wireless propagation channel is needed for the development
and realistic assessment of V2V communication systems. We present a novel
geometry-based stochastic MIMO channel model with support for frequencies in
the band of 5.2-6.2 GHz. The model is based on extensive high-resolution
measurements at different road intersections in the city of Berlin, Germany. We
extend existing models, by including the effects of various obstructions,
higher order interactions, and by introducing an angular gain function for the
scatterers. Scatterer locations have been identified and mapped to measured
multi-path trajectories using a measurement-based ray tracing method and a
subsequent RANSAC algorithm. The developed model is parameterized, and using
the measured propagation paths that have been mapped to scatterer locations,
model parameters are estimated. The time variant power fading of individual
multi-path components is found to be best modeled by a Gamma process with an
exponential autocorrelation. The path coherence distance is estimated to be in
the range of 0-2 m. The model is also validated against measurement data,
showing that the developed model accurately captures the behavior of the
measured channel gain, Doppler spread, and delay spread. This is also the case
for intersections that have not been used when estimating model parameters.Comment: Submitted to IEEE Transactions on Vehicular Technolog
Rehabilitation Intervention for Individuals With Heart Failure and Fatigue to Reduce Fatigue Impact: A Feasibility Study
Objective:
To investigate feasibility of recruitment, tablet use in intervention delivery, and use of self-report outcome measures and to analyze the effect of Energy Conservation plus Problem-Solving Therapy versus Health Education interventions for individuals with heart failure-associated fatigue.
Methods:
This feasibility study was a block-randomized controlled trial involving 23 adults, blinded to their group assignment, in a rural southern area in the United States. Individuals with heart failure and fatigue received the interventions for 6 weeks through videoconferencing or telephone. Participants were taught to solve their fatigue-related problems using energy conservation strategies and the process of Problem-Solving Therapy or educated about health-related topics.
Results:
The recruitment rate was 23%. All participants completed the study participation according to their group assignment, except for one participant in the Energy Conservation plus Problem-Solving Therapy group. Participants primarily used the tablet (n=21) rather than the phone (n=2). Self-report errors were noted on Activity Card Sort (n=23). Reported fatigue was significantly lower for both the Energy Conservation plus Problem-Solving Therapy (p=0.03, r=0.49) and Health Education (p=0.004, r=0.64) groups. The Health Education group reported significantly lower fatigue impact (p=0.019, r=0.48). Participation was significantly different in low-physical demand leisure activities (p=0.008; r=0.55) favoring the Energy Conservation plus Problem-Solving Therapy group.
Conclusion:
The recruitment and delivery of the interventions were feasible. Activity Card Sort may not be appropriate for this study population due to recall bias. The interventions warrant future research to reduce fatigue and decrease participation in sedentary activities (Clinical Trial Registration number: NCT03820674)
Mapping the Pathways of Photo-induced Ion Migration in Organic-inorganic Hybrid Halide Perovskites
Organic-inorganic hybrid perovskites (OIHPs) exhibiting exceptional
photovoltaic and optoelectronic properties are of fundamental and practical
interest, owing to their tunability and low manufacturing cost. For practical
applications, however, challenges such as material instability and the
photocurrent hysteresis occurring in perovskite solar cells under light
exposure need to be understood and addressed. While extensive investigations
have suggested that ion migration is a plausible origin of these detrimental
effects, detailed understanding of the ion migration pathways remains elusive.
Here, we report the characterization of photo-induced ion migration in OIHPs
using \textit{in situ} laser illumination inside a scanning electron
microscope, coupled with secondary electron imaging, energy-dispersive X-ray
spectroscopy and cathodoluminescence with varying primary electron energies.
Using methylammonium lead iodide (MAPbI), formamidinium lead iodide
(FAPbI) and hybrid formamidinium-methylammonium lead iodide as model
systems, we observed photo-induced long-range migration of halide ions over
hundreds of micrometers and elucidated the transport pathways of various ions
both near the surface and inside the bulk of the OIHPs, including a surprising
finding of the vertical migration of lead ions. Our study provides insights
into ion migration processes in OIHPs that can aid OIHP material design and
processing in future applications
Single Read and Paired End mRNA-Seq Illumina Libraries from 10 Nanograms Total RNA
Whole transcriptome sequencing by mRNA-Seq is now used extensively to perform global gene expression, mutation, allele-specific expression and other genome-wide analyses. mRNA-Seq even opens the gate for gene expression analysis of non-sequenced genomes. mRNA-Seq offers high sensitivity, a large dynamic range and allows measurement of transcript copy numbers in a sample. Illumina’s genome analyzer performs sequencing of a large number (> 107) of relatively short sequence reads (< 150 bp).The "paired end" approach, wherein a single long read is sequenced at both its ends, allows for tracking alternate splice junctions, insertions and deletions, and is useful for de novo transcriptome assembly
Improved Gastrointestinal Symptoms and Quality of Life after Conversion from Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium in Renal Transplant Patients Receiving Tacrolimus
It is reported that a conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) relieves gastrointestinal (GI) symptom burden and improves health-related quality of life (HRQoL). However, it is unclear whether renal transplant recipients using tacrolimus receive the same benefit from the conversion. In this prospective, multi-center, open-label trial, patients were categorized into two groups by their GI symptom screening. Equimolar EC-MPS (n=175) was prescribed for patients with GI burdens; those with no complaints remained on MMF (n=83). Gastrointestinal Symptom Rating Scale (GSRS) and Gastrointestinal Quality of Life Index (GIQLI) were evaluated at baseline and after one month. Patients and physicians completed Overall Treatment Effect (OTE) at one month. EC-MPS-converted patients had worse GSRS and GIQLI scores at baseline than MMF-continued patients (all P<0.001). Significant improvements in GSRS and GIQLI scores were observed for EC-MPS-converted patients at one month, but MMF-continued patients showed worsened GSRS scores (all P<0.05). OTE scale indicated that EC-MPS patients improved in overall GI symptoms and HRQoL more than MMF patients did (P<0.001). In tacrolimus-treated renal transplant recipients with GI burdens, a conversion from MMF to EC-MPS improves GI-related symptoms and HRQoL
Endovascular Treatment of Isolated Common Iliac Artery Aneurysms With Short Necks Using Bifurcated Stent-Grafts
Elective surgical repair has traditionally been considered to be the treatment of choice for the exclusion of isolated iliac artery aneurysms (IAAs). Recently, endovascular repair has evolved as an alternative to surgical repair, especially in patients at high surgical risk. However, in the absence of sufficient proximal necks, iliac artery aneurysms are not suitable for direct deployment of a tubular-shaped endograft. Here we report two cases of IAAs with short proximal necks that were excluded using an endovascular bifurcated stent-graft. The bifurcated stent-graft was successfully deployed with complete exclusion of the aneurysm. In neither case was there evidence of procedural failures. There were no signs of significant complications. We conclude that endovascular repair of IAAs with short proximal necks is feasible and efficient using an endovascular bifurcated stent-graft
Intravenous KITENIN shRNA Injection Suppresses Hepatic Metastasis and Recurrence of Colon Cancer in an Orthotopic Mouse Model
KITENIN (KAI1 C-terminal interacting tetraspanin) promotes invasion and metastasis in mouse colon cancer models. In the present study, we evaluated the effects of KITENIN knockdown by intravenous administration of short hairpin RNAs (shRNAs) in an orthotopic mouse colon cancer model, simulating a primary or adjuvant treatment setting. We established orthotopic models for colon cancer using BALB/c mice and firefly luciferase-expressing CT-26 (CT26/Fluc) cells. Tumor progression and response to therapy were monitored by bioluminescence imaging (BLI). In the primary therapy model, treatment with KITENIN shRNA substantially delayed tumor growth (P = 0.028) and reduced the incidence of hepatic metastasis (P = 0.046). In the adjuvant therapy model, KITENIN shRNA significantly reduced the extent of tumor recurrence (P = 0.044). Mice treated with KITENIN shRNA showed a better survival tendency than the control mice (P = 0.074). Our results suggest that shRNA targeting KITENIN has the potential to be an effective tool for the treatment of colon cancer in both adjuvant and metastatic setting
Organic electrode coatings for next-generation neural interfaces
Traditional neuronal interfaces utilize metallic electrodes which in recent years have reached a plateau in terms of the ability to provide safe stimulation at high resolution or rather with high densities of microelectrodes with improved spatial selectivity. To achieve higher resolution it has become clear that reducing the size of electrodes is required to enable higher electrode counts from the implant device. The limitations of interfacing electrodes including low charge injection limits, mechanical mismatch and foreign body response can be addressed through the use of organic electrode coatings which typically provide a softer, more roughened surface to enable both improved charge transfer and lower mechanical mismatch with neural tissue. Coating electrodes with conductive polymers or carbon nanotubes offers a substantial increase in charge transfer area compared to conventional platinum electrodes. These organic conductors provide safe electrical stimulation of tissue while avoiding undesirable chemical reactions and cell damage. However, the mechanical properties of conductive polymers are not ideal, as they are quite brittle. Hydrogel polymers present a versatile coating option for electrodes as they can be chemically modified to provide a soft and conductive scaffold. However, the in vivo chronic inflammatory response of these conductive hydrogels remains unknown. A more recent approach proposes tissue engineering the electrode interface through the use of encapsulated neurons within hydrogel coatings. This approach may provide a method for activating tissue at the cellular scale, however, several technological challenges must be addressed to demonstrate feasibility of this innovative idea. The review focuses on the various organic coatings which have been investigated to improve neural interface electrodes
Optofluidic phantom mimicking optical properties of porcine livers
One strategy for assessing efficacy of a liver transplant is to monitor perfusion and oxygenation after transplantation. An implantable optical sensor is being developed to overcome inadequacies of current monitoring approaches. To facilitate sensor design while minimizing animal use, a polydimethylsiloxane (PDMS)-based liver phantom was developed to mimic the optical properties of porcine liver in the 630-1000 nm wavelength range and the anatomical geometry of liver parenchyma. Using soft lithography to construct microfluidic channels in pigmented elastomer enabled the 2D approximation of hexagonal liver lobules with 15mm sinusoidal channels, which will allow perfusion with blood-mimicking fluids to facilitate the development of the liver perfusion and oxygenation monitoring system
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