2,026 research outputs found
Boundary value problems for the stationary axisymmetric Einstein equations: a disk rotating around a black hole
We solve a class of boundary value problems for the stationary axisymmetric
Einstein equations corresponding to a disk of dust rotating uniformly around a
central black hole. The solutions are given explicitly in terms of theta
functions on a family of hyperelliptic Riemann surfaces of genus 4. In the
absence of a disk, they reduce to the Kerr black hole. In the absence of a
black hole, they reduce to the Neugebauer-Meinel disk.Comment: 46 page
Efficacy and tolerability of the Galanin Analog NAX 5055 in the multiple-hit rat model of symptomatic infantile spasms
Infantile spasms are seizures manifesting in infantile epileptic encephalopathies that are associated with poor epilepsy and cognitive outcomes. The current therapies are not always effective or are associated with serious side effects. Early cessation of spasms has been proposed to improve long-term outcomes. To identify new therapies for infantile spasms with rapid suppression of spasms, we are using the multiple-hit rat model of infantile spasms, which is a model of refractory infantile spasms. Here, we are testing the efficacy and tolerability of a single dose of the galanin receptor 1 preferring analog, NAX 5055, in the multiple-hit model of spasms. To induce the model, postnatal day 3 (PN3) male Sprague-Dawley rats underwent right intracerebral infusions of doxorubicin and lipopolysaccharide; p-chlorophenylalanine was then injected intraperitoneally (i.p.) at PN5. After the onset of spasms at PN4, 11-14 rats/group were injected i.p. with either NAX 5055 (0.5, 1, 2, or 4mg/kg) or vehicle. Video monitoring for spasms included a 1h pre-injection period, followed by 5h of recording post-injection, and two 2h sessions on PN5. The study was conducted in a randomized, blinded manner. Neurodevelopmental reflexes were assessed daily as well as at 2h after injection. Respiratory function, heart rate, pulse distension, oximetry and blood glucose were measured 4h after injection. The relative expression of GalR1 and GalR2 mRNA over β-actin in the cerebral cortex and hippocampus was determined with real time reverse transcription polymerase chain reaction. There was no acute effect of NAX 5055 on spasm frequency after the single dose of NAX 5055 (n=11-13 rats/group, following exclusions). Neurodevelopmental reflexes, vital signs, blood glucose measured 4h post-injection, and survival were not affected. A reduction in pulse and breath distention of unclear clinical significance was observed with the 7mg/kg NAX 5055 dose. GalR1 mRNA was present in the cerebral cortex and hippocampus of PN4 and adult rats. The hippocampal - but not the cortical - GalR1 mRNA expression was significantly lower in PN4 pups than in adults. GalR1 mRNA was also at least 20 times less abundant in the PN4 cortex than GalR2 mRNA. In conclusion, a single dose of NAX 5055 has no acute efficacy on spasms or toxicity in the multiple hit rat model of medically refractory infantile spasms. Our findings cannot exclude the possibility that repetitive NAX 5055 administration may show efficacy on spasms. The higher expression of GalR2 in the PN4 cortex suggests that GalR2-preferring analogs may be of interest to test for efficacy on spasms
The spectrum of the random environment and localization of noise
We consider random walk on a mildly random environment on finite transitive
d- regular graphs of increasing girth. After scaling and centering, the
analytic spectrum of the transition matrix converges in distribution to a
Gaussian noise. An interesting phenomenon occurs at d = 2: as the limit graph
changes from a regular tree to the integers, the noise becomes localized.Comment: 18 pages, 1 figur
Conductivity sum rule, implication for in-plane dynamics and c-axis response
Recently observed -axis optical sum rule violations indicate non-Fermi
liquid in-plane behavior. For coherent -axis coupling, the observed flat,
nearly frequency independent -axis conductivity implies
a large in-plane scattering rate around and therefore any
pseudogap that might form at low frequency in the normal state will be smeared.
On the other hand incoherent -axis coupling places no restriction on the
value of and gives a more consistent picture of the observed sum rule
violation which, we find in some cases, can be less than half.Comment: 3 figures. To appear in PR
The effect on membrane translocation and perturbation by modulating the helicity of cell-penetrating peptides
Topological phase due to electric dipole moment and magnetic monopole interaction
We show that there is an anologous Aharonov-Casher effect on a neutral
particle with electric dipole moment interacting with a magnetic filed produced
by magnetic monopoles.Comment: 8 page
Radiative Corrections for Pion Polarizability Experiments
We use the semi-analytical program RCFORGV to evaluate radiative corrections
to one-photon radiative emission in the high-energy scattering of pions in the
Coulomb field of a nucleus with atomic number Z. It is shown that radiative
corrections can simulate a pion polarizability effect. The average effect was
estimated for pion energies 40-600 GeV. We also study the range of
applicability of the equivalent photon approximation in describing one-photon
radiative emission.Comment: 11 pages (LaTex), 6 figures, 1 table. No changes in the paper. New
submission because old files are corrupted in arXi
An experimental measurement of corona discharge using laser Dopplervelocimetry
A point to plane testing discharge system was constructed allowing the flow of air to pass, circulate and return to its initial status, when corona is initiated by the alternating applied voltage on the stressed electrode. The corona wind velocity was measured by means of a laser Doppler velocimetry system implemented and calibrated in the laboratory. The velocity measurement was carried out without disturbing the field configuration intensity or the wind flow. The direction and pattern of the corona electric wind was visualized and observed through a laser curtain; this was achieved by guiding smoke to the discharge medium near the stressed electrode. Velocity measurements were obtained for various radial distances r, taken on the central discharge axis for several inter-electrode distances b. The direct observation of the obtained data shows an increase of the corona wind velocity with the applied voltage and the corona discharge current and substantial decrease as the radial distance is enlarged. An experimental investigation was conducted in the research laboratory to use electric wind corona discharge and enhance the available information supporting the corona discharge and applied voltage relationship along with the geometrical system parameter
The STAT5 transcription factor in B-cells of patients with chronic lymphocytic leukemia
Aim. To find out the cause of inhibition of the IL2-STAT5 signaling pathway in chronic lymphocytic leukemia (CLL) cells. Methods.CLL cells were isolated from peripheral blood, using gradient centrifugation on a ficoll-verografin mixture. Expression of the STAT1-6 genes at the mRNA level was analyzed, using the Oncomine database. Expression, phosphorylation status and cellular localization of the STAT5 protein were studied by fluorescence microscopy, using specific antibodies. Results.Unlike B-cells of healthy donors, expression of the STAT5A protein was low in the patient CLL cells. As we have previously shown, the IL-2-STAT5 (JAK-STAT5) signaling pathway is inhibited in CLL cells. Now we demonstrated a low level of phosphorylation of the STAT5 protein, or a complete lack of phosphorylation in CLL cells. The STAT5A protein shows cytoplasmic localization, indicating the absence of complexes in the nucleus that activate/repress transcription of the STAT5-dependent genes. Conclusions. Inhibition of the IL-2-STAT5 pathway in CLL cells is caused by a lack of the STAT5 proteins phosphorylation and/or the absence of the active STAT5A transcription complexes in the nucleus of CLL cells.Мета. Встановити причину блокування сигнального шляху IL2-STAT5 у клітинах крові хворих на хронічний ліфмолейкоз (ХЛЛ). Методи. Клітини ХЛЛ виділяли з периферичної крові пацієнтів, хворих на ХЛЛ, за допомогою центрифугування у градієнтіфікол-верографін. Експресію генів STAT1-6 на рівні мРНК аналізували за допомогою бази даних Oncomine. Експресію, статус фосфорилювання і клітинну локалізацію білка STAT5 вивчали методом флуоресцентної мікроскопії з використаннім специфічних антитіл. Результати. Навідмінувід В-клітин здорових людей, експресія білка STAT5А була низькою у клітинах хворих на ХЛЛ. Як нами було встановлено раніше, сигнальний шлях IL-2-STAT5 (JAK-STAT5) інгібовано у клітинах ХЛЛ. Нами було показано низький рівень фосфорилювання білків STAT5, або повну відсутність фосфорильованої форми протеїнів в лейкемічних клітинах. Протеїн STAT5А показує цитоплазматичну локалізацію, що вказує н авідсутність у ядрікомплексів, активуючих транскрипцію генів, залежних від фактора транскрипції STAT5. Висновки. Інгибування сигнального клітинного шляху IL-2-STAT5 в клітинах крові хворих на ХЛЛ реалізується за рахунок гіпофосфорилювання протеїнів STAT5 та/або відсутності активних комплексів транскрипції STAT5А у ядрі лейкемичних клітин.Цель. Установить причину блокирования сигнального пути IL2-STAT5 в клетках крови больных хроническим лимфолейкозом (ХЛЛ). Методы. Лейкемические клетки выделяли из периферической крови с помощью центрифугирования в градиенте плотности фиколл-верографин. Экспрессию генов STAT1-6 на уровне мРНК анализировали с помощью базы данных Oncomine. Экспрессию, статус фосфорилирования и клеточную локализацию белка STAT5 изучали методом флуоресцентной микроскопии с использованием специфических антител. Результаты. В отличие от В-клеток здоровых людей, экспрессия белка STAT5А была низкой в клетках больных ХЛЛ. Как нами было установлено ранее, сигнальный путь IL-2-STAT5 (JAK-STAT5) ингибирован в клетках ХЛЛ. Намибылпоказаннизкийуровеньфосфорилированиябелков STAT5 или полное отсутствие фосфорилированной формы протеинов в лейкемических клетках. Протеин STAT5А показывает цитоплазматическую локализацию, что указывает на отсутствие в ядре комплексов, активирующих транскрипцию генов, зависимых от фактора транскрипции STAT5. Выводы. Ингибирование сигнального клеточного пути IL-2-STAT5 в клетках крови больных ХЛЛ происходит за счёт гипофосфорилирования белков STAT5 и/или отсутствия активных комплексов транскрипции STAT5А в ядре лейкемических клеток
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