Fabrication and in vitro deployment of a laser-activated shape memory polymer vascular stent

<p>Abstract</p> <p>Background</p> <p>Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP) stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an <it>in vitro </it>artery model.</p> <p>Methods</p> <p>A novel SMP stent was fabricated from thermoplastic polyurethane. A solid SMP tube formed by dip coating a stainless steel pin was laser-etched to create the mesh pattern of the finished stent. The stent was crimped over a fiber-optic cylindrical light diffuser coupled to an infrared diode laser. Photothermal actuation of the stent was performed in a water-filled mock artery.</p> <p>Results</p> <p>At a physiological flow rate, the stent did not fully expand at the maximum laser power (8.6 W) due to convective cooling. However, under zero flow, simulating the technique of endovascular flow occlusion, complete laser actuation was achieved in the mock artery at a laser power of ~8 W.</p> <p>Conclusion</p> <p>We have shown the design and fabrication of an SMP stent and a means of light delivery for photothermal actuation. Though further studies are required to optimize the device and assess thermal tissue damage, photothermal actuation of the SMP stent was demonstrated.</p

In Search of Cellular Immunophenotypes in the Blood of Children with Autism

Autism is a neurodevelopmental disorder characterized by impairments in social behavior, communication difficulties and the occurrence of repetitive or stereotyped behaviors. There has been substantial evidence for dysregulation of the immune system in autism.We evaluated differences in the number and phenotype of circulating blood cells in young children with autism (n = 70) compared with age-matched controls (n = 35). Children with a confirmed diagnosis of autism (4-6 years of age) were further subdivided into low (IQ<68, n = 35) or high functioning (IQ ≥ 68, n = 35) groups. Age- and gender-matched typically developing children constituted the control group. Six hundred and forty four primary and secondary variables, including cell counts and the abundance of cell surface antigens, were assessed using microvolume laser scanning cytometry.There were multiple differences in immune cell populations between the autism and control groups. The absolute number of B cells per volume of blood was over 20% higher for children with autism and the absolute number of NK cells was about 40% higher. Neither of these variables showed significant difference between the low and high functioning autism groups. While the absolute number of T cells was not different across groups, a number of cellular activation markers, including HLA-DR and CD26 on T cells, and CD38 on B cells, were significantly higher in the autism group compared to controls.These results support previous findings that immune dysfunction may occur in some children with autism. Further evaluation of the nature of the dysfunction and how it may play a role in the etiology of autism or in facets of autism neuropathology and/or behavior are needed

MANGROVE FOREST COVER EXTRACTION OF THE COASTAL AREAS OF NEGROS OCCIDENTAL, WESTERN VISAYAS, PHILIPPINES USING LIDAR DATA

Mangroves have a lot of economic and ecological advantages which include coastal protection, habitat for wildlife, fisheries and forestry products. Determination of the extent of mangrove patches in the coastal areas of the Philippines is therefore important especially in resource conservation, protection and management. This starts with a well-defined and accurate map. LiDARwas used in the mangrove extraction in the different coastal areas of Negros Occidental in Western Visayas, Philippines. Total coastal study area is 1,082.55 km² for the 14 municipalities/ cities processed. Derivatives that were used in the extraction include, DSM, DTM, Hillshade, Intensity, Number of Returns and PCA. The RGB bands of the Orthographic photographs taken at the same time with the LiDAR data were also used as one of the layers during the processing. NDVI, GRVI and Hillshade using Canny Edge Layer were derived as well to produce an enhanced segmentation. Training and Validation points were collected through field validation and visual inspection using Stratified Random Sampling. The points were then used to feed the Support Vector Machine (SVM) based on tall structures. Only four classes were used, namely, Built-up, Mangroves, Other Trees and Sugarcane. Buffering and contextual editing were incorporated to reclassify the extracted mangroves. Overall accuracy assessment is at 98.73% (KIA of 98.24%) while overall accuracy assessment for Mangroves only is at 98.00%. Using this workflow, mangroves can already be extracted in a large-scale level with acceptable overall accuracy assessments

Gene regulatory networks shape developmental plasticity of root cell types under water extremes in rice

: Understanding how roots modulate development under varied irrigation or rainfall is crucial for development of climate-resilient crops. We established a toolbox of tagged rice lines to profile translating mRNAs and chromatin accessibility within specific cell populations. We used these to study roots in a range of environments: plates in the lab, controlled greenhouse stress and recovery conditions, and outdoors in a paddy. Integration of chromatin and mRNA data resolves regulatory networks of the following: cycle genes in proliferating cells that attenuate DNA synthesis under submergence; genes involved in auxin signaling, the circadian clock, and small RNA regulation in ground tissue; and suberin biosynthesis, iron transporters, and nitrogen assimilation in endodermal/exodermal cells modulated with water availability. By applying a systems approach, we identify known and candidate driver transcription factors of water-deficit responses and xylem development plasticity. Collectively, this resource will facilitate genetic improvements in root systems for optimal climate resilience

Nuclear transcriptomes at high resolution using retooled INTACT

Breakthrough Technologies - Focus IssueIsolated nuclei provide access to early steps in gene regulation involving chromatin as well as transcript production and processing. Here, we describe transfer of the isolation of nuclei from tagged specific cell types (INTACT) to the monocot rice (Oryza sativa L.). The purification of biotinylated nuclei was redesigned by replacing the outer nuclear-envelope-targeting domain of the nuclear tagging fusion (NTF) protein with an outer nuclear-envelope-anchored domain. This modified NTF was combined with codon-optimized Escherichia coli BirA in a single T-DNA construct. We also developed inexpensive methods for INTACT, T-DNA insertion mapping, and profiling of the complete nuclear transcriptome, including a ribosomal RNA degradation procedure that minimizes pre-ribosomal RNA (pre-rRNA) transcripts. A high-resolution comparison of nuclear and steady-state poly(A)+ transcript populations of seedling root tips confirmed the capture of pre-messenger RNA (pre-mRNA) and exposed distinctions in diversity and abundance of the nuclear and total transcriptomes. This retooled INTACT can enable high-resolution monitoring of the nuclear transcriptome and chromatin in specific cell types of rice and other species

Nuclear Transcriptomes at High Resolution Using Retooled INTACT

Breakthrough Technologies - Focus IssueInternational audienceIsolated nuclei provide access to early steps in gene regulation involving chromatin as well as transcript production and processing. Here, we describe transfer of the isolation of nuclei from tagged specific cell types (INTACT) to the monocot rice (Oryza sativa L.). The purification of biotinylated nuclei was redesigned by replacing the outer nuclear-envelope-targeting domain of the nuclear tagging fusion (NTF) protein with an outer nuclear-envelope-anchored domain. This modified NTF was combined with codon-optimized Escherichia coli BirA in a single T-DNA construct. We also developed inexpensive methods for INTACT, T-DNA insertion mapping, and profiling of the complete nuclear transcriptome, including a ribosomal RNA degradation procedure that minimizes pre-ribosomal RNA (pre-rRNA) transcripts. A high-resolution comparison of nuclear and steady-state poly(A)+ transcript populations of seedling root tips confirmed the capture of pre-messenger RNA (pre-mRNA) and exposed distinctions in diversity and abundance of the nuclear and total transcriptomes. This retooled INTACT can enable high-resolution monitoring of the nuclear transcriptome and chromatin in specific cell types of rice and other species

Magnetic resonance flow velocity and temperature mapping of a shape memory polymer foam device

<p>Abstract</p> <p>Background</p> <p>Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment.</p> <p>Methods</p> <p>A laser-heated SMP foam device was deployed in a simplified <it>in vitro </it>vascular model. Magnetic resonance imaging (MRI) techniques were used to assess the fluid dynamics and thermal changes associated with device deployment.</p> <p>Results</p> <p>Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired.</p> <p>Conclusions</p> <p>Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.</p