1,137 research outputs found
Nonlocal charges of T-dual strings
We obtain sets of infinite number of conserved nonlocal charges of strings in
a flat space and pp-wave backgrounds, and compare them before and after
T-duality transformation. In the flat background the set of nonlocal charges is
the same before and after the T-duality transformation with interchanging odd
and even-order charges. In the IIB pp-wave background an infinite number of
nonlocal charges are independent, contrast to that in a flat background only
the zero-th and first order charges are independent. In the IIA pp-wave
background, which is the T-dualized compactified IIB pp-wave background, the
zero-th order charges are included as a part of the set of nonlocal charges in
the IIB background. To make this correspondence complete a variable conjugate
to the winding number is introduced as a Lagrange multiplier in the IIB action
a la Buscher's transformation.Comment: 23 pages, 1 figur
Marek's Disease Virus Down-Regulates Surface Expression of MHC (B Complex) Class I (BF) Glycoproteins during Active but not Latent Infection of Chicken Cells
AbstractInfection of chicken cells with three Marek's disease virus (MDV) serotypes interferes with expression of the major histocompatibility complex (MHC or B complex) class I (BF) glycoproteins. BF surface expression is blocked after infection of OU2 cells with MDV serotypes 1, 2, and 3. MDV-induced T-cell tumors suffer a nearly complete loss of cell surface BF upon virus reactivation with 5-bromo-2′-deoxyuridine (BUdR). The recombinant virus (RB1BUS2gfpΔ) transforming the MDCC-UA04 cell line expresses green fluorescent protein (GFP) during the immediate early phase of viral gene expression. Of the UA04 cells induced to express the immediate early GFP, approximately 60% have reduced levels of BF expression. All of the reactivated UA04 and MSB1 tumor cells expressing the major early viral protein pp38 display reduced levels of BF. Thus, BF down-regulation begins in the immediate early phase and is complete by the early phase of viral gene expression. The intracellular pool of BF is not appreciably affected, indicating that the likely mechanism is a block in BF transport and not the result of transcriptional or translational regulation
Coronal mass ejections as expanding force-free structures
We mode Solar coronal mass ejections (CMEs) as expanding force-fee magnetic
structures and find the self-similar dynamics of configurations with spatially
constant \alpha, where {\bf J} =\alpha {\bf B}, in spherical and cylindrical
geometries, expanding spheromaks and expanding Lundquist fields
correspondingly. The field structures remain force-free, under the conventional
non-relativistic assumption that the dynamical effects of the inductive
electric fields can be neglected. While keeping the internal magnetic field
structure of the stationary solutions, expansion leads to complicated internal
velocities and rotation, induced by inductive electric field. The structures
depends only on overall radius R(t) and rate of expansion \dot{R}(t) measured
at a given moment, and thus are applicable to arbitrary expansion laws. In case
of cylindrical Lundquist fields, the flux conservation requires that both axial
and radial expansion proceed with equal rates. In accordance with observations,
the model predicts that the maximum magnetic field is reached before the
spacecraft reaches the geometric center of a CME.Comment: 19 pages, 9 Figures, accepted by Solar Physic
Acidity of Creamery Butter and Its Relation to Quality
The first intention in beginning these investigations on acidity of butter was to trace the relationship between the quality or score, and the acidity of the butter. If there should be a uniform relation between the two, then it would be possible, at least in part to use an acid test in judging or scoring butter. The senses of taste, smell and sight have not always given satisfaction. A person\u27s judgment is elastic, and all judges do not have the same standard, while an acid test is definite. If any uniform relation existed, a certain percentage of the points in the score card might be based on the acid test. During the last two years at different seasons, butter from different creameries has been sent to this experiment station, at which place it has been scored or judged by well known butter experts, as shown in the following tables, and at the same time tested for acid. Butter from different states was judged and tested for acid in the Chicago market. In addition, many lots of butter have been manufactured, judged, and tested at the experiment station. These tests and scores have been carefully studied, the results compared, and conclusions are herein reported
Creamery Butter
The results reported in this Bulletin are a continuation of the investigations on the acidity of creamery butter, a preliminary report of which was published as Bulletin No. 116 of this Station under the title, Acidity of Creamery Butter and Its Relation to Quality. In this latter Bulletin it was shown that no definite relation was found to exist between the score and the acidity of fresh butter, but that experiments then in progress indicated that the acid test was a fair measure of the extent and rapidity of the deterioration of butter held in storage. Investigations on the acidity of cold storage butter, amount and nature of acids and other decomposition products of butter, and their relation to rancid and ill-flavored butter are now in progress and results will be reported in future publications
Heat to Electricity Conversion by a Graphene Stripe with Heavy Chiral Fermions
A conversion of thermal energy into electricity is considered in the
electrically polarized graphene stripes with zigzag edges where the heavy
chiral fermion (HCF) states are formed. The stripes are characterized by a high
electric conductance Ge and by a significant Seebeck coefficient S. The
electric current in the stripes is induced due to a non-equilibrium thermal
injection of "hot" electrons. This thermoelectric generation process might be
utilized for building of thermoelectric generators with an exceptionally high
figure of merit Z{\delta}T \simeq 100 >> 1 and with an appreciable electric
power densities \sim 1 MW/cm2.Comment: 8 pages, 3 figure
Phase II study of CC-486 (oral azacitidine) in previously treated patients with locally advanced or metastatic nasopharyngeal carcinoma
BACKGROUND: Treatment options are limited for recurrent nasopharyngeal carcinoma (NPC). We report results from a phase II study of CC-486 (oral azacitidine) in advanced NPC. PATIENTS AND METHODS: Patients with locally advanced or metastatic NPC and 1-2 prior treatment regimens received CC-486 300 mg daily on days 1-14 of 21-day cycles until disease progression or unacceptable toxicity. The first 6 patients of Asian-Pacific Islander (API) ethnicity received a reduced dose of 200 mg to preserve safety and tolerability; if well tolerated, subsequent API patients received CC-486 300 mg. The study could advance to stage 2 if > 4 patients achieved a response. Co-primary end-points were overall response rate (ORR) and progression-free survival (independent review). Key secondary end-points were overall survival and safety. RESULTS: Owing to faster-than-anticipated enrolment, 36 patients, including 13 of API ethnicity, were enrolled; the median age was 54.0 years. Most patients were male (81%) and had an Eastern Cooperative Oncology Group performance status 64 1 (97%). Among 25 efficacy-evaluable patients, the ORR was 12%; the median progression-free and overall survival were 4.7 and 18.0 months, respectively. The most common grade III/IV treatment-emergent adverse events were neutropenia (33%) and febrile neutropenia (11%). Twenty-one posttreatment deaths, primarily due to progressive disease or disease complications, and 1 on-treatment death (epistaxis, unrelated to study drug) occurred. The study did not advance to stage 2. CONCLUSION: CC-486 did not show sufficient clinical activity to support further development as monotherapy in this patient population. The safety profile of CC-486 in NPC was consistent with that in other solid tumours
Selenium poisoning in livestock: a review and progress
Selenium in certain soils may be taken up by plants in amounts to render them
toxic. Seleniferous forage can be found in most of the western states. Intoxication
of livestock by seleniferous plants has been classified as acute and chronic. Acute
poisoning results from consumption of plants having high levels of Se; chronic Se
poisoning has been described in two forms— alkali disease and blind staggers. Alkali
disease is said to result from the consumption of seleniferous grains and grasses,
and is manifest by loss of hair, lameness, and loss of weight. Blind staggers is slid
to result from the consumption of Se indicator plants and is manifest by wandering,
circling, loss of ability to swallow, and blindness. Some research casts doubt on the
above classification of Se poisoning. Research using pigs (Sus scrofa domesticus) indicates
that the source of Se does not alter the type of lesion or signs of poisoning
observed. There are data available that suggest that blind staggers is not related to
Se poisoning
Statistical mechanics of RNA folding: importance of alphabet size
We construct a minimalist model of RNA secondary-structure formation and use
it to study the mapping from sequence to structure. There are strong,
qualitative differences between two-letter and four or six-letter alphabets.
With only two kinds of bases, there are many alternate folding configurations,
yielding thermodynamically stable ground-states only for a small set of
structures of high designability, i.e., total number of associated sequences.
In contrast, sequences made from four bases, as found in nature, or six bases
have far fewer competing folding configurations, resulting in a much greater
average stability of the ground state.Comment: 7 figures; uses revtex
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