3,388 research outputs found
Spectrophotomatic Assay for the Enzyme Catalyzed Reaction of 4-nitroquinoline 1-oxide with Glutathione
4-Nitroquinoline 1-oxide (4NQO(is a toxic and carcinogenic compound that has been reported to be subject to conjugation with glutathione (GSH). This reaction may proceed non-enzymatically or be catalyzed by GSH transferases. The non-enzymatic rate for this reaction has been reported to be very high. The purposes of this investigation were to develop a spectrophotometric assay for the reaction of4NQO with GSH and to determine whether the rate for the enzyme catalyzed reaction was significant relative to the non-enzymatic reaction. The absorbance spectrum of 4NQO in phosphate buffer exhibited a maximum at 365 nm. Reaction of 4NQO with GSH was accompanied by a shift to 353 nm and an absorbance increase which was maximal at 350 nm. The formation of product could be quantitated from the increase in absorbance at 350 nm, where the change in the millimolar extinction coefficient was 7.20 mM^-1 cm^-1. Although the non-enzymatic reaction of 4NQO and GSH proceeded rapidly at or above pH 8, at physiological pH this reaction was largely enzyme dependent. In an assay system containing 0.1 mM 4NQO, 1 mM GSH, and 0.1 M potassium phosphate, at 25°C, the conjugation of 4NQO with GSH by mouse livercytosol was optimal at pH 6.5 - 7.5. At pH 6.5 and 1 mM GSH, a GSH transferase purified from mouse liver catalyzed the reaction of 4NQO with GSH with a maximum velocity of 156 μmoles/min per mg of protein. The Km for 4NQO was 35 μM. The high activity of liver cytosol in promoting the reaction of 4NQO with GSH and the high affinity of the purified GSH transferase for 4NQO suggest that enzymatic catalysis of this reaction may be of considerable significance in vivo
Virginia\u27s \u27Affiliated Transactions\u27 Statute: Indulging Form over Substance in Second Generation Takeover Legislation
Virginia\u27s recently enacted antitakeover statute, the Affiliated Transactions provision of the Virginia Stock Corporation Act, raises serious constitutional and economic questions. Although the form of the statute appears to regulate the internal affairs of Virginia corporations, the substance and practical impact of the statute render it violative of both the commerce and supremacy clauses. Constitutional analysis of state antitakeover legislation necessitates consideration of the economic desirability of an unrestricted market for corporate control. The United States Supreme Court\u27s most recent statement on the subject, in CTS Corp. v. Dynamics Corp. of America, decided on April 21, 1987, reflects a noteworthy retreat from the Court\u27s position in Edgarv. MITE. The debate concerning the role of economic analysis in the constitutional scrutiny of state antitakeover legislation, as well as the question whether such legislation is truly consistent with shareholder interests, appears to be far from settled
Evidence for the importance of resonance scattering in X-ray emission line profiles of the O star Puppis
We fit the Doppler profiles of the He-like triplet complexes of \ion{O}{7}
and \ion{N}{6} in the X-ray spectrum of the O star Puppis, using
XMM-Newton RGS data collected over ks of exposure. We find that they
cannot be well fit if the resonance and intercombination lines are constrained
to have the same profile shape. However, a significantly better fit is achieved
with a model incorporating the effects of resonance scattering, which causes
the resonance line to become more symmetric than the intercombination line for
a given characteristic continuum optical depth . We discuss the
plausibility of this hypothesis, as well as its significance for our
understanding of Doppler profiles of X-ray emission lines in O stars.Comment: 29 pages, 8 figures, revised version accepted by Ap
High frequency oscillator comprising cointegrated thin film resonator and active device
A cointegrated high frequency oscillator including a thin film resonator and activedevices formed on the same semiconductor substrate and by a process which is compatible with formation of both the thin film resonator and the active devices. The processes utilized in formation of the thin film resonator are adapted to microelectronic processing techniques such that the steps of formation of the active devices and the thin film resonator can be intermixed to the degree necessary to allow, for example, the metallization layers to serve as elements both of the active devices and the thin film resonator
Perancangan Aplikasi Panduan Belajar Pengenalan Ortodonsia Menggunakan Animasi 3D
--- Perancangan aplikasi panduan belajar pengenalan ortodonsia menggunakan animasi 3D merupakan e-learning, yang dibuat untuk menjelaskan alat bantu ajar mata kuliah ortodonsia dengan menggunakan teknologi animasi 3D. Mengubah materi dan ilustrasi berupa animasi 3D yang menarik sehingga mahasiswa lebih mudah mengerti. Data yang di jadikan sebagai kebutuhan pembuatan aplikasi didapatkan dari wawancara kepada dosen pengampu mata kuliah ortodonsia di fakultas kedokteran gigi UNSRAT. Metode pengembangan aplikasi yang digunakan adalah Rapid Aplication Development. Dengan teknologi yang digunakan, tools pembuatan 3 Dimensi blender dan Blender Game Engine untuk membuat aplikasi interaktif. Kata Kunci -- Ortodonsia, RAD, e-learning Abstrak --- Perancangan aplikasi panduan belajar pengenalan ortodonsia menggunakan animasi 3D merupakan e-learning, yang dibuat untuk menjelaskan alat bantu ajar mata kuliah ortodonsia dengan menggunakan teknologi animasi 3D. Mengubah materi dan ilustrasi berupa animasi 3D yang menarik sehingga mahasiswa lebih mudah mengerti. Data yang di jadikan sebagai kebutuhan pembuatan aplikasi didapatkan dari wawancara kepada dosen pengampu mata kuliah ortodonsia di fakultas kedokteran gigi UNSRAT. Metode pengembangan aplikasi yang digunakan adalah Rapid Aplication Development. Dengan teknologi yang digunakan, tools pembuatan 3 Dimensi blender dan Blender Game Engine untuk membuat aplikasi interaktif. Kata Kunci -- Ortodonsia, RAD, e-learnin
Why Major Programs Need Innovation Support Labs: An Example from the Space Shuttle Launch Program at KSC
For over 30 years the Kennedy Space Center (KSC) has processed the Space Shuttle; handling all hands-on aspects from receiving the Orbiter, External Tanks, Solid Rocket Booster Segments, and Payloads, through certification, check-out, and assembly, and ending with fueling, count-down, and launch. A team of thousands have worked this highly complicated, yet supremely organized, process and have, as a consequence, generated an exceptional amount of technology to solve a host of problems. This paper describes the contributions of one team that formed with the express purpose to help solve some of these diverse Shuttle ground processing problems
Characterization, renovation, and utilization of water from slurry transport systems
The transportation of a number of commodities as water slurries in pipelines offers a number of advantages which will make this method of transport more popular in coming years. Among the formeost of these advantages are high reliability, low operating costs, minimum environmental disruption, and ability to operate with nonpetroleum energy resources. Although coal is the most frequently mentioned material that is a candidate for slurry transport, other commodities including minerals, wood chips, and even solid refuse may be moved in this manner. Water used as a slurry transport medium must be properly characterized, renovated, and used in order to make slurry transport environmentally and economically acceptable.Project # B-145-MO Agreement # 14-34-0001-121
The Spin Structure of a Polarized Photon
We show that the first moment of the spin-dependent structure function
of a real photon vanishes independent of the momentum
transfer it is probed with. This result is non-perturbative: it holds to
all orders in perturbation theory in abelian and non-abelian gauge theory and
at every twist.Comment: LaTex, 13 page
An Untranslated cis-Element Regulates the Accumulation of Multiple C4 Enzymes in Gynandropsis gynandra Mesophyll Cells.
C4 photosynthesis is a complex phenotype that allows more efficient carbon capture than the ancestral C3 pathway. In leaves of C4 species, hundreds of transcripts increase in abundance compared with C3 relatives and become restricted to mesophyll (M) or bundle sheath (BS) cells. However, no mechanism has been reported that regulates the compartmentation of multiple enzymes in M or BS cells. We examined mechanisms regulating CARBONIC ANHYDRASE4 (CA4) in C4 Gynandropsis gynandra. Increased abundance is directed by both the promoter region and introns of the G. gynandra gene. A nine-nucleotide motif located in the 5' untranslated region (UTR) is required for preferential accumulation of GUS in M cells. This element is present and functional in three additional 5' UTRs and six 3' UTRs where it determines accumulation of two isoforms of CA and pyruvate,orthophosphate dikinase in M cells. Although the GgCA4 5' UTR is sufficient to direct GUS accumulation in M cells, transcripts encoding GUS are abundant in both M and BS. Mutating the GgCA4 5' UTR abolishes enrichment of protein in M cells without affecting transcript abundance. The work identifies a mechanism that directs cell-preferential accumulation of multiple enzymes required for C4 photosynthesis.We would like to thank the BBSRC for funding.This is the author accepted manuscript. The final version is available from the American Society of Plant Biologists via http://dx.doi.org/10.​1105/​tpc.​15.​0057
Avoided Critical Behavior in O(n) Systems
Long-range frustrating interactions, even if their strength is infinitesimal,
can give rise to a dramatic proliferations of ground or near-ground states. As
a consequence, the ordering temperature can exhibit a discontinuous drop as a
function of the frustration. A simple model of the doped Mott insulator, where
the short-range tendency of the holes to phase separate competes with
long-range Coulomb effects, exhibits this "avoided critical" behavior. This
model may serve as a paradigm for many other systems.Comment: 4 pages, 2 figure
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