206 research outputs found

    A Ka-Band High Data Rate Shipboard Satellite Terminal

    Get PDF
    A fully articulated steerable shipboard satellite antenna system operating at Ka-band was developed by engineers from the Naval Research Laboratory (NRL), NASA\u27s Glenn Research Center, and a number of industry partners. A series of tests conducted in October of 1998 on Lake Michigan achieved an unparalleled data rate transmission of 45 megabits per second (Mbps) between a moving vessel at sea and a fixed-earth station using NASA\u27s Advanced Communications Technology Satellite (ACTS). Network and application layer tests ran concurrently with the data rate transmission trials, examining TCP/IP file transfers, video and voice transfer technologies, and Asynchronous Transfer Mode (ATM) techniques. This experiment, called the Shipboard ACTS Ka-band Experiment (SHAKE), collected a data set of time-correlated measurements. The samples, collected at one-second (or faster) intervals, included vessel motion, RF and IF (modem) measurements. DS-3 layer port statistics, ATM layer statistics, TCP/IP statistics, and application performance. This data set (discussed herein) represents the one of the most comprehensive collections of its type ever recorded on a vessel. Tracking was measured at various sea states and weather conditions, including seas that generated peak pitch variations on the vessel of + 12 degrees, and peak roll variations of + 24 degrees. The SHAKE experiment, utilizing a combination of commercial-off-the-shelf (COTS) and government hardware, clearly illustrated the viability of high data rate (HDR) Ka-band systems for ship-to-shore communications. The system, which was developed over a period of four months, was tested during a two-week period on Lake Michigane on a 45-foot Bayliner Motor Yacht. Entropy. Underlying networking, protocol, terminal, and bandwidth-on-demand issues, combined with variable bit rate servive and HDR capabilities, present challenges not typically addressed in current Naval SATCOM systems. Through this study, numerous system optimizations were documented, which are presented as work remaining in order to realize reliable services that would support Naval HDR shipboard SATCOM requirements using commercially-available Ka-Band satellite systems

    Rapid and efficient stable gene transfer to mesenchymal stromal cells using a modified foamy virus vector

    Get PDF
    Mesenchymal stromal cells (MSCs) hold great promise for regenerative medicine. Stable ex vivo gene transfer to MSCs could improve the outcome and scope of MSC therapy, but current vectors require multiple rounds of transduction, involve genotoxic viral promoters and/or the addition of cytotoxic cationic polymers in order to achieve efficient transduction. We describe a self-inactivating foamy virus vector (FVV), incorporating the simian macaque foamy virus envelope and using physiological promoters, which efficiently transduces murine MSCs (mMSCs) in a single-round. High and sustained expression of the transgene, whether GFP or the lysosomal enzyme, arylsulphatase A (ARSA), was achieved. Defining MSC characteristics (surface marker expression and differentiation potential), as well as long-term engraftment and distribution in the murine brain following intracerebroventricular delivery, are unaffected by FVV transduction. Similarly, greater than 95% of human MSCs (hMSCs) were stably transduced using the same vector, facilitating human application. This work describes the best stable gene transfer vector available for mMSCs and hMSCs

    Advanced Shipboard Communications Demonstrations with ACTS

    Get PDF
    For ships at sea, satellites provide the only option for high data rate (HDR), long haul communications. Furthermore the demand for HDR satellite communications (SATCOM) for military and commercial ships, and other offshore platforms is increasing. Presently the bulk of this maritime HDR SATCOM connectivity is provided via C-band and X-band. However, the shipboard antenna sizes required to achieve a data rate of, say T1 (1.544 Mbps) with present C-/X-band SATCOM systems range from seven to ten feet in diameter. This limits the classes of ships to which HDR services can be provided to those which are large enough to accommodate the massive antennas. With its high powered K/Ka-band spot beams, the National Aeronautics and Space Administration\u27s (NASA) Advanced Communications Technology Satellite (ACTS) was able to provide T1 and higher rate services to ships at sea using much smaller shipboard antennas. This paper discusses three shipboard HDR SATCOM demonstrations that were conducted with ACTS between 1996 and 1998. The first demonstration involved a 2 Mbps link provided to the seismic survey ship M/V Geco Diamond equipped with a 16-inch wide, 4.5-inch tall, mechanically steered slotted waveguide array antenna developed by the Jet Propulsion Laboratory. In this February 1996 demonstration ACTS allowed supercomputers ashore to process Geco Diamond\u27s voluminous oceanographic seismic data in near real time. This capability allowed the ship to adjust its search parameters on a daily basis based on feedback from the processed data, thereby greatly increasing survey efficiency. The second demonstration was conducted on the US Navy cruiser USS Princeton (CG 59) with the same antenna used on Geco Diamond. Princeton conducted a six-month (January-July 1997) Western Hemisphere solo deployment during which time T1 connectivity via ACTS provided the ship with a range of valuable tools for operational, administrative and quality-of-life tasks. In one instance, video teleconferencing (VTC) via ACTS allowed the ship to provide life-saving emergency medical aid, assisted by specialists ashore, to a fellow mariner - the Master of a Greek cargo ship. The third demonstration set what is believed to be the all-time SATCOM data rate record to a ship at sea, 45 Mbps in October 1998. This Lake Michigan (Chicago area) demonstration employed one of ACTS\u27 fixed beams and involved the smallest of the three vessels, the 45-foot Bayliner M/V Entropy equipped with a modified commercial-off-the-shelf one-meter antenna. A variety of multi-media services were provided to Entropy through a stressing range of sea states. These three demonstrations provided a preview of the capabilities that could be provided to future mariners on a more routine basis when K/Ka-band SATCOM systems are widely deployed

    A comparison of the molecular mechanisms underpinning high-intensity, pulsed polychromatic light and low-intensity UV-C hormesis in tomato fruit

    Get PDF
    Postharvest treatment of tomato fruit with high-intensity, pulsed polychromatic light (HIPPL) has previously been shown to induce delayed ripening and disease resistance comparable to that of low-intensity UV-C (LIUV). Little, however, is known of the mechanisms underpinning postharvest HIPPL hormesis in tomato fruit. Expression of genes involved in plant hormone biosynthesis, defence, secondary metabolism and ripening were monitored 24 h post treatment (24 HPT), 10 d post treatment (10 DPT) and 12 h post inoculation with Botrytis cinerea (12 HPI). All genes monitored were constitutively expressed and changes in expression profiles following treatment were highly similar for both HIPPL and LIUV treatments. Expression of pathogenesis-related proteins P4, β-1,3,-Glucanase and Chitinase 9 and a jasmonate biosynthesis enzyme (OPR3), were significantly upregulated at 10 DPT and 12 HPI. Both treatments significantly downregulated the expression of polygalacturonase and flavonol synthase at 10 DPT and 12 HPI. Ethylene biosynthesis enzyme ACO1 and β-carotene hydroxylase were significantly upregulated at 24 HPT, and phenylalanine ammonia-lyase (PAL) was significantly upregulated at 12 HPI. Both HIPPL and LIUV treatments stimulate defence responses that are mediated by salicylic acid, jasmonic acid and ethylene. This may lead to broad range resistance against both necrotrophic and biotrophic pathogens as well as abiotic stresses and herbivorous pests. Following inoculation with B. cinerea only PAL showed indication of a gene priming response for HIPPL- and LIUV-treated fruit

    A comparison of low intensity UV-C and high intensity pulsed polychromatic sources as elicitors of hormesis in tomato fruit

    Get PDF
    Post-harvest hormetic treatment of mature green tomato fruit (Solanum lycopersicum cv. Mecano) with high intensity pulsed polychromatic light (HIPPL) significantly delayed ripening to levels comparable to those achieved using a conventional low intensity UV-C (LIUV) source. A 16 pulse HIPPL treatment reduced the ΔTCI (tomato colour index) by 50.1 % whilst treatment with a LIUV source led to a reduction of 43.1 %. Moreover, the 16 pulse treatment also induced disease resistance in the fruit to Botrytis cinerea with a 41.7 % reduction in disease progression compared to a 38.1 % reduction for the LIUV source. A single 16 pulse HIPPL treatment was found to significantly reduce disease progression on both mature green and ripe fruit with a 28.5 % reduction on ripe fruit in comparison to 13.4 % for the LIUV treatment. It is shown here that delayed ripening and disease resistance are local responses in side treated tomato fruit for both LIUV and HIPPL treatments. Finally, utilising a 16 pulse HIPPL treatment would reduce treatment times from 370 s for LIUV sources to 10 s per fruit - a 97.3 % reduction

    Deep sequencing of virus derived small interfering RNAs and RNA from viral particles shows highly similar mutational landscape of a plant virus population.

    Get PDF
    RNA viruses exist within a host as a population of mutant sequences, often referred to as quasispecies. Within a host, sequences of RNA viruses constitute several distinct but interconnected pools, such as RNA packed in viral particles, double-stranded RNA, and virus-derived small interfering RNAs. We aimed to test if the same representation of within-host viral population structure could be obtained by sequencing different viral sequence pools. Using ultradeep Illumina sequencing, the diversity of two coexisting Potato virus Y sequence pools present within a plant was investigated: RNA isolated from viral particles and virus-derived small interfering RNAs (the derivatives of a plant RNA silencing mechanism). The mutational landscape of the within-host virus population was highly similar between both pools, with no notable hotspots across the viral genome. Notably, all of the single-nucleotide polymorphisms with a frequency of higher than 1.6% were found in both pools. Some unique single-nucleotide polymorphisms (SNPs) with very low frequencies were found in each of the pools, with more of them occurring in the small RNA (sRNA) pool, possibly arising through genetic drift in localized virus populations within a plant and the errors introduced during the amplification of silencing signal. Sequencing of the viral particle pool enhanced the efficiency of consensus viral genome sequence reconstruction. Nonhomologous recombinations were commonly detected in the viral particle pool, with a hot spot in the 3′ untranslated and coat protein regions of the genome. We stress that they present an important but often overlooked aspect of virus population diversity. IMPORTANCE This study is the most comprehensive whole-genome characterization of a within-plant virus population to date and the first study comparing diversity of different pools of viral sequences within a host. We show that both virus-derived small RNAs and RNA from viral particles could be used for diversity assessment of within-plant virus population, since they show a highly congruent portrayal of the virus mutational landscape within a plant. The study is an important baseline for future studies of virus population dynamics, for example, during the adaptation to a new host. The comparison of the two virus sequence enrichment techniques, sequencing of virus-derived small interfering RNAs and RNA from purified viral particles, shows the strength of the latter for the detection of recombinant viral genomes and reconstruction of complete consensus viral genome sequence

    Recurrent encephalopathy: NAGS (N-Acetylglutamate Synthase) deficiency in adults

    Get PDF
    N-acetyl-glutamate synthase (NAGS) deficiency is a rare autosomal recessive urea cycle disorder (UCD) that uncommonly presents in adulthood. Adult presentations of UCDs include; confusional episodes, neuropsychiatric symptoms and encephalopathy. To date, there have been no detailed neurological descriptions of an adult onset presentation of NAGS deficiency. In this review we examine the clinical presentation and management of UCDs with an emphasis on NAGS deficiency. An illustrative case is provided. Plasma ammonia levels should be measured in all adult patients with unexplained encephalopathy, as treatment can be potentially life-saving. Availability of N-carbamylglutamate (NCG; carglumic acid) has made protein restriction largely unnecessary in treatment regimens currently employed. Genetic counselling remains an essential component of management of NAGS

    A comparison of low intensity UV-C and high intensity pulsed polychromatic sources as elicitors of hormesis in tomato fruit

    Get PDF
    Post-harvest hormetic treatment of mature green tomato fruit (Solanum lycopersicum cv. Mecano) with high intensity pulsed polychromatic light (HIPPL) significantly delayed ripening to levels comparable to those achieved using a conventional low intensity UV-C (LIUV) source. A 16 pulse HIPPL treatment reduced the ΔTCI (tomato colour index) by 50.1 % whilst treatment with a LIUV source led to a reduction of 43.1 %. Moreover, the 16 pulse treatment also induced disease resistance in the fruit to Botrytis cinerea with a 41.7 % reduction in disease progression compared to a 38.1 % reduction for the LIUV source. A single 16 pulse HIPPL treatment was found to significantly reduce disease progression on both mature green and ripe fruit with a 28.5 % reduction on ripe fruit in comparison to 13.4 % for the LIUV treatment. It is shown here that delayed ripening and disease resistance are local responses in side treated tomato fruit for both LIUV and HIPPL treatments. Finally, utilising a 16 pulse HIPPL treatment would reduce treatment times from 370 s for LIUV sources to 10 s per fruit - a 97.3 % reduction

    Transcriptional Profiling of Endocrine Cerebro-Osteodysplasia Using Microarray and Next-Generation Sequencing

    Get PDF
    BACKGROUND: Transcriptome profiling of patterns of RNA expression is a powerful approach to identify networks of genes that play a role in disease. To date, most mRNA profiling of tissues has been accomplished using microarrays, but next-generation sequencing can offer a richer and more comprehensive picture. METHODOLOGY/PRINCIPAL FINDINGS: ECO is a rare multi-system developmental disorder caused by a homozygous mutation in ICK encoding intestinal cell kinase. We performed gene expression profiling using both cDNA microarrays and next-generation mRNA sequencing (mRNA-seq) of skin fibroblasts from ECO-affected subjects. We then validated a subset of differentially expressed transcripts identified by each method using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Finally, we used gene ontology (GO) to identify critical pathways and processes that were abnormal according to each technical platform. Methodologically, mRNA-seq identifies a much larger number of differentially expressed genes with much better correlation to qRT-PCR results than the microarray (r² = 0.794 and 0.137, respectively). Biologically, cDNA microarray identified functional pathways focused on anatomical structure and development, while the mRNA-seq platform identified a higher proportion of genes involved in cell division and DNA replication pathways. CONCLUSIONS/SIGNIFICANCE: Transcriptome profiling with mRNA-seq had greater sensitivity, range and accuracy than the microarray. The two platforms generated different but complementary hypotheses for further evaluation

    MELAS: A multigenerational impact of the MTTL1 A3243G MELAS mutation

    Get PDF
    Background: the maternally inherited MTTL1 A3243G mutation in the mitochondrial genome causes MelaS (Mitochondrial encephalopathy lactic acidosis with Stroke-like episodes), a condition that is multisystemic but affects primarily the nervous system. Significant intra-familial variation in phenotype and severity of disease is well recognized. Methods: retrospective and ongoing study of an extended family carrying the MTTL1 A3243G mutation with multiple symptomatic individuals. tissue heteroplasmy is reviewed based on the clinical presentations, imaging studies, laboratory findings in affected individuals and pathological material obtained at autopsy in two of the family members. Results: there were seven affected individuals out of thirteen members in this three generation family who each carried the MTTL1 A3243G mutation. the clinical presentations were varied with symptoms ranging from hearing loss, migraines, dementia, seizures, diabetes, visual manifestations, and stroke like episodes. three of the family members are deceased from MelaS or to complications related to MelaS. Conclusions: the results of the clinical, pathological and radiological findings in this family provide strong support to the current concepts of maternal inheritance, tissue heteroplasmy and molecular pathogenesis in MelaS. neurologists (both adult and paediatric) are the most likely to encounter patients with MelaS in their practice. genetic counselling is complex in view of maternal inheritance and heteroplasmy. newer therapeutic options such as arginine are being used for acute and preventative management of stroke like episodes. © 2014 Canadian Journal of neurologiCal sciences inc
    • …
    corecore