11,305 research outputs found
RAM function is dependent on Kapβ2-mediated nuclear entry
No full textEukaryotic gene expression is dependent on the modification of the first transcribed nucleotide of pre-mRNA by the addition of the 7-methylguanosine cap. The cap protects transcripts from exonucleases and recruits complexes which mediate transcription elongation, processing and translation initiation. The cap is synthesised by a series of reactions which link 7-methylguanosine to the first transcribed nucleotide via a 5' to 5' triphosphate bridge. In mammals, cap synthesis is catalysed by the sequential action of RNGTT (RNA guanylyltransferase and 5'-phosphatase) and RNMT (RNA guanine-7 methyltransferase), enzymes recruited to RNA pol II during the early stages of transcription. We recently discovered that the mammalian cap methyltransferase is a heterodimer consisting of RNMT and the RNMT-activating subunit, RAM (RNMT-activating mini-protein). RAM activates and stabilises RNMT and thus is critical for cellular cap methylation and cell viability. Here we report that RNMT interacts with the N-terminal 45 amino acids of RAM, a domain necessary and sufficient for maximal RNMT activation. In contrast, smaller components of this RAM domain are sufficient to stabilise RNMT. RAM functions in the nucleus and we report that nuclear import of RAM is dependent on PY nuclear localisation signals and Kapß2 nuclear transport protein
Deformation and Aerodynamic Performance of a Ram-Air Wing
No full textRam-air wings form an ever increasing market of soft fabric, air inflated wings. They are primairily used in air sports such as parachuting, paragliding and kiting. Ram-air kites may also be used for electric power generation by letting the kite pull a cable from a drum that is connected to a generator. An example if this principle is the Laddermill concept. But since ram-air wings are flexible by nature they will deform and depart from their intended design shape when they are loaded by aerodynamic forces. These deformations generally affect the performance of the wings adversely. Kites with a higher lift-to-drag ratio on the Laddermill could mean a direct increase of the energy produced per square meter of kite. Besides this benefit for the Laddermill there is a huge, world-wide market of parachuting, paragliding and kiting that can benefit from more research and a better understanding of the deformation and aerodynamic performance of ram-air wings. The goals of this thesis are to be able to point out where a ram-air kite departs from the intended design shape, to investigate how well the kite performs, to understand how the deformations affect the airflow and to make suggestions for possible improvements of the design. Since little has been published about these subjects this report will most of all form a basis for further research. This report presents a method to analyse the shape and the aerodynamics of a ram-air kite. The kite is tested in the windtunnel. Its 3D shape is captured using two techniques: photogrammetry and laser scanning. Using the geometry data the structural deformation of the wing is dissected. With computational fluid dynamics the aerodynamics of the deformed shape is analyzed. An extra result of this study is the comparison of photogrammetry and laser scanning in terms of their suitability to capture the 3D shape of the ram-air kite. A number of interesting deformations and flow features were found on the ram-air wing: - Theoretically the bumps (ballooning) and grooves on a ram-air wing hinder the spanwise flow on a 3-dimensional wing, but in practise this effect is only visible on small parts of the upper surface. - The pull of the suspension lines on the under surface and the internal construction of the wing make the upper surface of the wing deform. This results in a decrease of the upper surface curvature, especially near the nose. This curvature decrease causes a loss of lift of at least 5%. - Because the flat, 2-dimensional fabric is inflated into a 3-dimensional shape the fabric wrinkles. The wrinkles continue from the top and bottom surface into the ribs that internally connect and support the top and bottom surface. On average these wrinkles shorten the ribs in chordwise direction by 3.5%. This decreases the surface area of the wing and it makes the ribs effectively thicker. Many more details became visible with the thorough analysis of the wing’s shape. The conclusion is that the performance of the ram-air wing can be improved by changing these details. The photogrammetry measuring technique gave better results than laser scanning and is very suitable tool to make these details visible. It allows a designer to identify where the real flying shape deviates from the design shape. This can help kite designers and designers of other ram-air wings to reverse-Aerospace Engineerin
Astronomical Applications Of New Line Lists For Cn, C2 And Their Isotopologues
No full textFor cool stellar and substellar objects, atomic lines weaken, and detailed elemental and isotopic abundances are often derived from molecular absorption features. We have embarked on a project to provide molecular line lists by combining experimental observations for line positions with ab initio calculations for line strengths. So far we have results for MgH (A-X and B-X transitions)\footnote{E. GharibNezhad, A. Shayesteh and P. F. Bernath, Mon. Notices R. Astro. Soc. 432, 2043-2047 (2013)}\footnote{K. H. Hinkle, L. Wallace, R. S. Ram, P. F. Bernath, C. Sneden and S. Lucatello, Astrophys. J. Suppl. 207, 26 (7pp) (2013)}, C (Swan system)\footnote{J. S. A. Brooke, P. F. Bernath, T. W. Schmidt and G. B. Bacskay, J. Quant. Spectrosc. Rad. Trans. 124, 11-20 (2013)}\footnote{R. S. Ram, J. S. A. Brooke, P. F. Bernath, C. Sneden and S. Lucatello, Astrophys. J. Suppl. 211, 5 (7pp) (2014)}, CN (red and violet systems)\footnote{J. S. A. Brooke, R. S. Ram, C. M. Western, G. Li, D. W. Schwenke and P. F. Bernath, Astrophys. J. Suppl. 210, 23 (15pp) (2014)}, CP (A-X transition)\footnote{R. S. Ram, J. S. A. Brooke, C.M. Western and P. F. Bernath, J. Quant. Spectrosc. Rad. Transfer (in press)}, NH (vibration-rotation bands) and OH (Meinel system)\footnote{J. S. A. Brooke et al., this meeting, P301}. This talk will briefly describe the new line lists for the Swan system (d-a) of C and CC, and the red (A-X) and violet (B-X) systems of CN, CN and CN. Applications to the spectra of carbon-enhanced metal-poor stars, the K-giant Arcturus, the metal-rich open cluster NGC 6791, the Sun and comets will be presented.Made available in DSpace on 2014-09-17T16:56:06Z (GMT). No. of bitstreams: 3
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Previous issue date: 2014-06-1
Numerical simulation of ram extrusion in short-fiber-reinforced fresh cementitious composites
No full textThis is the author's accepted manuscript. The final published article is available from the link below. First published in JoMMS in 4(10), 2009, published by Mathematical Sciences Publishers.A series of ram extrusion tests was carried out on a short-fiber-reinforced, semisolid, fresh cementitious composite. An elastoviscoplastic constitutive model is proposed for the extrudable fresh cementitious composite. It features the associative flow rule, a nonlinear strain rate-hardening law, and the von Mises yield criterion. The model is then implemented in ANSYS/LS-DYNA explicit finite element code.
Various ram extrusion processes of the fresh cementitious composite were simulated. It has been found that the extrusion load versus imposed displacement predictions agree well with the experimental results. The fresh paste flow, through the die entry and the die-land, is then interpreted in light of the evolution of the deformation and distribution of state variables, mainly based on numerical results and the ram extrusion mechanism.
The effects of extrusion ratio and extrusion velocity on extrusion load are also investigated, based on the mechanical properties of the fresh cementitious composite. The study indicates that the numerical procedure established, together with the constitutive model proposed, is applicable for describing ram extrusion of short-fiber-reinforced fresh cementitious composites, which might provide a numerical rheometric tool from which ram extrusion of elastoviscoplastic paste-like materials can be examined and quantified.Hong Kong Research Grant Council and China Ministry of Science and Technology
A One Transistor RAM for MPC Projects
No full textMany MPC projects, such as video frame buffers, need a large memory subsystem. A one transistor per bit dynamic memory using Mead-Conway design rules is being designed with this purpose in mind. The memory cell size is 16.5 λ by 8λ (about the same size as a 1975 4K RAM cell with λ = 2.5 microns).
While a complete high density memory subsystem has not been designed, two chips have been designed to test its major components. One chip is a 1K memory array that tests the sense amplifier, column decoder/driver, and read/write logic. This chip lacks a timing generator and clock drivers. The second chip tests some low power bootstrapped clock drivers. These test chips are currently being fabricated
Scientometric portrait of Ram Gopal Rastogi
No full textPublication productivity of Indian scientist (R.G. Rastogi) has been documented.
Scientometric analysis of 312 papers by Ram Gopal Rastogi published during 1954 to 1992 in various domains: (a) Luni -solar activity and quiet -time E & F- region (57); (b) Equatorial electric field and low and mid latitude iof:osphere (78); (c) Ionospheric E- region irregularities (19); (dj Ionospheric F- region irregularities (32); and (e) Magnetic disturbance effects on the equatorial low and mid latitude ionosphere (23) were analysed. Interdomainery contents and of the number of papers: a+b were 36; b+c and b+d were 20 each; b+e were 16;. c+e were 5; a+e were 3; d+e were 2; and a+d had only one publication. Highest collaborations were with H. Chandra (61), M.R. Deshpande (42), and G. Sethia (19) out of his total 97 collaborators. His highest productivity was during 1978 with 28 papers followed by 19 papers during 1977. The core journals preferred by him for publishing papers were: Indian Journal of Radio & Space Physics, India, and Journal of Atomic & Terrestrial Physics, UK (59 each), followed by Proceedings of the Indian Academy of Sciences, India (34). Most prolific title keywords with their frequencies were: Ionosphere (92); Equatorial (61); F-region (53); Equatorial electrojet region (40), and Magnetic equator (30)
ram cat
No full textram-cat nAn adult I've been told about used an unusual frightening figure to induce sleep in her son. The threat was, "If you don't go to sleep I'll give you to the Ram Cats."DNE-citW. J. KIRWIN JAN 1976JH JAN 1976Used I and SupUsed IUsed IOnly the portion of the quote in quotation marks appears in the dictionary
ram n
No full textram nMany sealing vessels were equipped with rams, two long poles attached to opposite sides of the bow and lashed together just below the bowsprit.PRINTED ITEM DNE SupG. M. Story AUG. 9 1989W. J. KIRWINUsed SupUsed SupUsed Su
Ram-jet Performance
No full textThe ram jet is basically one of the most dimple types of aircraft engine. It consists only of an inlet diffuser, a combustion system, and an exit nozzle. A typical ram-jet configuration is shown in figure 128. The engine operates on the Brayton cycle, and ideal cycle efficiency depends only on the ratio of engine to ambient pressure. The increased, engine pressures are obtained by ram action alone, and for this reason the ram jet has zero thrust at zero speed. Therefore, ram-jet-powered aircraft must be boosted to flight speeds close to a Mach number of 1.0 before appreciable thrust is generated by the engine. Since pressure increases are obtained by ram action alone, combustor-inlet pressures and temperatures are controlled by the flight speed, the ambient atmospheric condition, and by the efficiency of the inlet diffuser. These pressures and temperatures, as functions of flight speed and altitude, are shown in figure 129 for the NACA standard atmosphere and for practical values of diffuser efficiency. It can be seen that very wide ranges of combustor-inlet temperatures and pressures may be encountered over the ranges of flight velocity and altitude at which ram jets may be operated. Combustor-inlet temperatures from 500 degrees to 1500 degrees R and inlet pressures from 5 to 100 pounds per square inch absolute represent the approximate ranges of interest in current combustor development work. Since the ram jet has no moving parts in the combustor outlet, higher exhaust-gas temperatures than those used in current turbojets are permissible. Therefore, fuel-air ratios equivalent to maximum rates of air specific impulse or heat release can be used, and, for hydrocarbon fuels, this weight ratio is about 0.070. Lower fuel-air ratios down to about 0.015 may also be required to permit efficient cruise operation. This fuel-air-ratio range of 0.015 to 0.070 used in ram jets can be compared with the fuel-air ratios up to 0.025 encountered in current turbojets. Ram-jet combustor-inlet velocities range from 150 to 400 feet per second. These high linear velocities combined with the relatively low pressure ratios obtainable in ram jets require that the pressure drop through the combustor be kept low to avoid excessive losses in cycle efficiency. It has been estimated that, for a long-range ram-jet engine, an increase in pressure loss of one dynamic head would require a compensating 1-percent increase in combustion efficiency. Therefore, combustor pressure-loss coefficients (pressure drop/impact pressure) of the order of 1 to 4 are found in most current engines. The operating conditions described impose major problems in the design of stable and efficient ram-jet combustion systems. This chapter presents a survey of ram-jet combustor research and, where possible, points out criteria that may be useful in the design of ram-jet combustion systems
CHARACTERISTIC OF FROZEN-THAWED EPIDIDYMAL SPERMATOZOA AND REFRIGERATED STORAGE OF RAM SPERMATOZOA
No full textPost-mortem spermatozoa recovery is an important technique for obtaining germplasm reserves
from genetically valuable animals or endangered species. The purpose of this study was to study
whether ram spermatozoa within epididymides stored at 4º C for 24 and 48 h remain their motility and
viability. The characteristic of ram epididymal spermatozoa after freezing and thawing was also
observed. Six pairs of ram testes with attached epididymides were used in this study. The motility of
control spermatozoa was well maintained throughout the dilution procedure (83.3±1.1, 80±1.3, and
80±1.3% for collection, Niwa and Sasaki freezing -1 extender (NSF-1 and NSF-2 groups respectively);
but declined (P<0.05) after freezing and thawing (38.3±3.1%). Motile and viable spermatozoa could be
recovered from epididymides up to 48 h of storage, although their quality declined significantly
(P<0.05) as post-mortem storage time increased (motility: 83±1.2, 67±3.0, and 46±5.1; viability:
84.2±2.4, 73±2.8, and 66.6±2.6 % for control, 24 h and 48 h group respectively). These data indicate
that ram epididymides could be stored at 4º C for 48 h when epididymal spermatozoa cannot be
immmediately collected and cryopreserved. These storage conditions might be possible to use for
epididymal sperm recovery in wild ruminants.
Keywords: epididymal spermatozoa, Freezing, ram, refrigeratio
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