7,928 research outputs found
Increased expression of aggrecan and biglycan mRNA in Achilles tendinopathy
To determine the expression of mRNA encoding the proteoglycans aggrecan, versican, biglycan and decorin in mid-tendon samples of chronic painful Achilles tendinopathy and ruptured Achilles tendons, compared with normal tendons. Total RNA isolated from frozen tendon samples (14 normal, 13 painful, 14 ruptured) was assayed by relative quantitative reverse transcription polymerase chain reaction for aggrecan, versican, biglycan and decorin mRNA, normalized using 18S rRNA. Differences between sample groups were tested by univariate analysis of variance with age as co-variate. In normal tendon samples expression of each of the proteoglycan mRNA decreased with increasing age. Decorin mRNA was the most highly-expressed of the proteoglycan mRNA, while versican mRNA expression was higher (3.8-fold) than that of aggrecan. In painful tendinopathy both aggrecan and biglycan mRNA expression increased (more than 10-fold and 5-fold, respectively) compared with normal tendon samples, but levels of versican and decorin mRNA were not significantly changed. In ruptured tendons the levels of aggrecan, biglycan and versican mRNA were not changed compared with normal tendon samples, but decorin mRNA decreased markedly. Increased aggrecan and biglycan mRNA expression in painful tendinopathy resembles the pattern in fibrocartilaginous regions of tendon, and may reflect an altered mechanical environment at the site of the lesion. Increased aggrecan mRNA expression may underlie the increase in glycosaminoglycan observed in painful tendinopathy
Versican splice variant messenger RNA expression in normal human Achilles tendon and tendinopathies
Versican is the principal large proteoglycan expressed in mid-tendon, but its role in tendon pathology is unknown. Our objective was to define the expression of versican isoform splice variant messenger ribonucleic acid (mRNA) in normal Achilles tendons, in chronic painful tendinopathy and in ruptured tendons. Total RNA isolated from frozen tendon samples (normal n = 14; chronic painful tendinopathy n = 10; ruptured n = 8) was assayed by relative quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for total versican, versican variants V0, V1, V2, V3 and type I collagen a1 mRNA, normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Differences between sample groups were tested by Wilcoxon statistics. Painful and ruptured tendons showed a significant decrease (median 2-fold) in the expression of versican mRNA, in contrast to an increased expression (median 8-fold) of type I collagen a1 mRNA in painful tendons. Versican splice variants V0 and V1 mRNA were readily detected in normal samples, V3 levels were substantially lower, and V2 levels were more variable. Each of V1, V2 and V3 mRNA showed significant decreases in expression in painful and ruptured tendons, but V0 was not significantly changed. Changes in versican expression relative to that of collagen, and alterations in the balance of versican splice variants, may contribute to changes in matrix structure and function in tendinopathies
Mobile Offloading in Residential Wireless Access Markets
The growth of mobile data traffic has been increasing at a tremendous pace. Currently, mobile broadband is mostly served by macro base stations. Strong attenuation occurs when the signals penetrate through buildings affecting the quality of service. Hence, mobile operators need to enhance the capacity to minimise congestion problems and improve the coverage on their macro networks for better network operation. As most of the mobile traffic occurs indoors, there is a need for indoor network deployments.
A qualitative analysis employing the combination of various research methods (value network configuration, system dynamics, expert interviews) has been carried out to investigate various factors besides mobile offloading, which could lead to a large-scale deployment of femtocells in homes with the focus on Finland. This study also discusses several options to cope with the mobile traffic growth and examines different indoor network deployment scenarios. Furthermore, the scenarios of Femtocell-as-a-Service are highlighted and its possible impacts on mobile operators’ business are covered as well. The analysis is also conducted to illustrate how different actors are interrelated in the home network business.
The analysis reveals that the primary factor that will contribute to the success of femtocell deployment in homes is the need for future mobile offloading. However, many other factors have important implications which require careful consideration by mobile operators. With the presence of good macro network capacity like in Finland, new services and partnership with third party providers has been identified as the most important factor. Mobile operators need to offer an incentive to attract end-users to adopt a femtocell service due to the strong positioning of WiFi in homes. Therefore, new services would also enable the penetration of femtocells into homes to compete with WiFi access points. Three factors (interference mitigation and interoperability, femtocell management system, backhaul) are also important as these are needed to ensure the femtocell networks operate reliably. As lowering the cost is essential for building scale, the model of Femtocell-as-a-Service is useful as it reduces capital investments for mobile operators. Interviews with the experts found that major mobile operators are less likely to adopt this model. This is better suited for smaller mobile operators that want to quickly enter the femtocell business
Hybrid User Pairing for Spectral and Energy Efficiencies in Multiuser MISO-NOMA Networks with SWIPT
In this paper, we propose a novel hybrid user pairing (HUP) scheme in multiuser multiple-input single-output nonorthogonal multiple access networks with simultaneous wireless information and power transfer. In this system, two information users with distinct channel conditions are optimally paired while energy users perform energy harvesting (EH) under non-linearity
of the EH circuits. We consider the problem of jointly optimizing user pairing and power allocation to maximize the overall spectral efficiency (SE) and energy efficiency (EE) subject to userspecific quality-of-service and harvested power requirements. A new paradigm for the EE-EH trade-off is then proposed to achieve a good balance of network power consumption. Such
design problems are formulated as the maximization of nonconcave functions subject to the class of mixed-integer non-convex constraints, which are very challenging to solve optimally. To
address these challenges, we first relax binary pairing variables to be continuous and transform the design problems into equivalent non-convex ones, but with more tractable forms. We then develop low-complexity iterative algorithms to improve the objectives and converge to a local optimum by means of the inner approximation framework. Simulation results show the convergence of proposed algorithms and the SE and EE improvements of the proposed
HUP scheme over state-of-the-art designs. In addition, the effects of key parameters such as the number of antennas and dynamic power at the BS, target data rates, and energy threshold, on the system performance are evaluated to show the effectiveness of the proposed schemes in balancing resource utilization
Organ-Specific and Development Regulation of the Nopaline Synthase Promoter in Transgenic Tobacco Plants
Control regions of the nopaline synthase (nos) gene have been widely used to express foreign genes in plants since the promoter is active in a wide variety of plant tissues. We report here the characteristics of the nos promoter activity in transgenic tobacco (Nicotiana tabacum) plants at various developmental stages. The promoter was highly active in the lower parts of a plant and gradually decreased in the upper parts. This vertical gradient was maintained throughout plant growth until the flowering stage when the overall promoter strength decreased significantly in the vegetative organs. However, in various flower organs, the nos promoter activities increased dramatically. Higher activity was observed in calyx, corolla, and stamens although the maximum promoter activity in each organ was found at different stages of flower development. The promoter activity in pistils was low and gradually increased in the ovaries after anthesis. In developing fruits, the nos promoter activity was strongly induced during the mid-stage of embryogenesis. These results indicate that the expression of the nos promoter is developmentally regulated and organ specific in transgenic tobacco plants
Regrouping metric-space search index for search engine size adaptation
This work contributes to the development of search engines that self-adapt their size in response to fluctuations in workload. Deploying a search engine in an Infrastructure as a Service (IaaS) cloud facilitates allocating or deallocating computational resources to or from the engine. In this paper, we focus on the problem of regrouping the metric-space search index when the number of virtual machines used to run the search engine is modified to reflect changes in workload. We propose an algorithm for incrementally adjusting the index to fit the varying number of virtual machines. We tested its performance using a custom-build prototype search engine deployed in the Amazon EC2 cloud, while calibrating the results to compensate for the performance fluctuations of the platform. Our experiments show that, when compared with computing the index from scratch, the incremental algorithm speeds up the index computation 2–10 times while maintaining a similar search performance
Growth factors regulate heterogeneous nuclear ribonucleoprotein K expression and function
Epidermal Growth Factor (EGF) family of growth factors and their receptors regulate normal and cancerous epithelial cell proliferation, a process that can be suppressed by antireceptor blocking antibodies. To identify genes whose expression may be modulated by antireceptor blocking antibodies, we performed a differential display screen with cells grown in the presence or absence of antireceptor blocking antibodies; isolates from one cDNA clone were 100% identical to human heterogeneous nuclear ribonucleoprotein K (hnRNP K), a protein with a conserved KH motif and RGG boxes, has been implicated in such functions as sequence-specific DNA binding, transcription, RNA binding and nucleocytoplasmic shuttling. Both EGF and heregulin-β1 induced expression of hnRNP K mRNA and protein in human breast cancer cells. This growth factor-mediated hnRNP K expression was effectively blocked by pretreatment of cultures with humanized anti-EGF Receptor (EGFR) antibody C225, or anti-human epidermal growth factor receptor-2 (HER2) antibody. Anti-EGFR monoclonal antibody also caused regression of human tumor xenografts and reduction in hnRNP K levels in athymic mice. Samples from grade III human breast cancer contained more hnRNP K protein than samples from grade II cancer. Finally, overexpression of hnRNP K in breast cancer cells significantly increased target c-myc promoter activity and c-Myc protein, hnRNP K protein levels, and enhanced breast cancer cell proliferation and growth in an anchorage-independent manner. These results suggested that the activity of human EGF receptor family members regulates hnRNP K expression by extracellular growth promoting signals and that therapeutic humanized antibodies against EGFR and HER2 can effectively block this function
PolarLight: a CubeSat X-ray Polarimeter based on the Gas Pixel Detector
The gas pixel detector (GPD) is designed and developed for high-sensitivity
astronomical X-ray polarimetry, which is a new window about to open in a few
years. Due to the small mass, low power, and compact geometry of the GPD, we
propose a CubeSat mission Polarimeter Light (PolarLight) to demonstrate and
test the technology directly in space. There is no optics but a collimator to
constrain the field of view to 2.3 degrees. Filled with pure dimethyl ether
(DME) at 0.8 atm and sealed by a beryllium window of 100 micron thick, with a
sensitive area of about 1.4 mm by 1.4 mm, PolarLight allows us to observe the
brightest X-ray sources on the sky, with a count rate of, e.g., ~0.2 counts/s
from the Crab nebula. The PolarLight is 1U in size and mounted in a 6U CubeSat,
which was launched into a low Earth Sun-synchronous orbit on October 29, 2018,
and is currently under test. More launches with improved designs are planned in
2019. These tests will help increase the technology readiness for future
missions such as the enhanced X-ray Timing and Polarimetry (eXTP), better
understand the orbital background, and may help constrain the physics with
observations of the brightest objects.Comment: Accepted for publication in Experimental Astronom
Can Solid-Organ-Transplanted Patients Perform a Cycling Marathon? Trends in Kidney Function Parameters in Comparison With Healthy Subjects.
Abstract Background Few solid-organ–transplanted patients (TP) perform regular sport activity. Poor data are available on the safety of intense and prolonged physical exercise on this population. The aim of the study was to evaluate kidney function parameters in a group of TP in comparison with healthy volunteers (HV) involved in a long-distance road cycling race: length 130 km and total uphill gradient, 1871 m. Methods Nineteen TP were recruited: 10 renal, 8 liver, and 1 heart and compared with 35 HV. Renal function parameters, namely, creatinine, estimated glomerular filtration rate (eGFR), urea, uric acid, urine specific gravity, microalbuminuria, and proteinuria were collected and their values were compared the day before the race (T1), immediately after crossing the finish line (T2), and 18 to 24 hours after the competition (T3). Results No adverse events were recorded. At baseline, TP showed lower values of eGFR (69 ± 22 versus 87 ± 13 mL/min/1.73 m 2 ), lower urine specific gravity (1015 ± 4 versus 1019 ± 6), and higher microalbuminuria (56 ± 74 versus 8 ± 15) and proteinuria values (166 ± 99 versus 74 ± 44) (in mg/L). At T2 in both groups, renal function parameters showed the same trends: decline of eGFR (54 ± 19 versus 69 ± 15 mL/min/1.73 m 2 ) and rise in protein excretion. At T3, functional parameters returned to baseline, except for urine specific gravity values remaining stable in TP (1018 ± 6) and growing higher in HV (1028 ± 4). Conclusions Selected and well-trained organ-transplanted patients can perform an intensive exercise, displaying temporary modifications on kidney function parameters comparable to healthy subjects, despite differences related to baseline clinical conditions and pharmacological therapies
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