186 research outputs found

    Fermions in Geodesic Witten Diagrams

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    We develop the embedding formalism for odd dimensional Dirac spinors in AdS and apply it to the (geodesic) Witten diagrams including fermionic degrees of freedom. We first show that the geodesic Witten diagram (GWD) with fermion exchange is equivalent to the conformal partial waves associated with the spin one-half primary field. Then, we explicitly demonstrate the GWD decomposition of the Witten diagram including the fermion exchange with the aid of the split representation. The geodesic representation of CPW indeed gives the useful basis for computing the Witten diagrams.Comment: 12 pages + appendices; v2: some comments and appendices added, published versio

    New Paradigms of Radiotherapy for Bone Metastasis

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    Proper care of patients with bone metastasis requires interdisciplinary treatments. Radiotherapy (RT) plays a central role in the management of painful bone metastasis. External beam RT can provide rapid successful palliation of painful bone metastasis in 50–80% of patients, is associated with very few adverse effects and leads to complete pain relief at the treated site in up to one‐third of patients. Intensity‐modulated RT (IMRT) or stereotactic body RT (SBRT) enables the delivery of higher doses to the target tumor while minimizing the dose to adjacent organs. Reirradiation using IMRT or SBRT is a valuable option for the management of bone metastases. A multidisciplinary team, especially one consisting of a spinal surgeon and rehabilitation physician, is particularly useful for treating patients with spinal bone metastases characterized by spinal instability. Rehabilitation intervention which increases the physical activity level and prevents deconditioning is important. Future developments in surgical procedures and RT will likely improve the management protocols for bone metastases and technology to reduce metal artifacts in radiation planning might improve the efficacy and safety of combination therapy

    Noise robust 2D bird localization via sound using microphone arrays

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    Birds in the wild are difficult to localize, because their sizes tend to be small, they move swiftly, and they are often visually occluded. However, their location information is crucial for ethological studies on birds' behaviour. Recently, automating the process has been studied as a hot topic, where spatial sensors and sensor networks are commonly used. To avoid the visual occlusion problem, many studies focus on acoustic signal processing by applying microphone arrays and perform 1D azimuth localization through bird songs. In this study, we perform 2D sound source localization in the Cartesian coordinates using azimuths from multiple microphone arrays. To estimate the exact bird's location, we calculate the intersection points of these azimuth lines. Although this approach is simple and easy to be implemented, it has two main issues. One is that even small noise interference in azimuth values results in corrupting the localization data. This leads to a problem, where the intersection points between the azimuth lines do not intersect in one point for a single bird, but in several points. This proves difficulty in estimating the exact location of each bird. Especially in a far-field application, even small noise corruption leads to large localization errors. The other issue is that in the bird's natural habitat, elements such as leaves, grass and rivers are natural noise sources. It is difficult to extract the bird songs in such a noisy environment. We propose an algorithm involving statistic methods, sound feature analysis and machine learning. Based on this approach, a noise robust bird localization system has been established. We have performed numerous simulations to further understand the limitations of the system. Based on the results we have also derived the system's design guidelines, describing how the results change depending on the number of microphone arrays, signal-to-noise ratio, bird's distance from the devices, array's transfer function, type of the singing bird and specific parameter settings used in the algorithms. Such detailed guidelines support interested researchers in creating a similar system, which can contribute to ethological researches

    Proximal Vertebral Body Fracture after 4-Level Fusion Using L1 as the Upper Instrumented Vertebra for Lumbar Degenerative Disease: Report of 2 Cases with Literature Review

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    Some cases with lumbar degenerative diseases require multi-level fusion surgeries. At our institute, 27 and 4 procedures of 3- and 4-level fusion were performed out of a total 672 posterior lumbar interfusions (PLIFs) on patients with lumbar degenerative disease from 2005 to 2010. We present 2 osteoporotic patients who developed proximal vertebral body fracture after 4-level fusion. Both cases presented with gait disability for leg pain by degenerative lumbar scoliosis and canal stenosis at the levels of L1/2-4/5. After 4-level fusion using L1 as the upper instrumented vertebra, proximal vertebral body fractures were found along with the right pedicle fractures of L1 in both cases. One of these patients, aged 82 years, was treated as an outpatient using a hard corset for 24 months, but the fractures were exacerbated over time. In the other patient, posterolateral fusion was extended from Th10 to L5. Both patients can walk alone and have been thoroughly followed up. In both cases, the fracture of the right L1 pedicle might be related to the subsequent fractures and fusion failure. In consideration of multi-level fusion, L1 should be avoided as an upper instrumented vertebra to prevent junctional kyphosis, especially in cases with osteoporosis and flat back posture

    FcɛRI-mediated mast cell degranulation requires calcium-independent microtubule-dependent translocation of granules to the plasma membrane

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    The aggregation of high affinity IgE receptors (Fcɛ receptor I [FcɛRI]) on mast cells is potent stimulus for the release of inflammatory and allergic mediators from cytoplasmic granules. However, the molecular mechanism of degranulation has not yet been established. It is still unclear how FcɛRI-mediated signal transduction ultimately regulates the reorganization of the cytoskeleton and how these events lead to degranulation. Here, we show that FcɛRI stimulation triggers the formation of microtubules in a manner independent of calcium. Drugs affecting microtubule dynamics effectively suppressed the FcɛRI-mediated translocation of granules to the plasma membrane and degranulation. Furthermore, the translocation of granules to the plasma membrane occurred in a calcium-independent manner, but the release of mediators and granule–plasma membrane fusion were completely dependent on calcium. Thus, the degranulation process can be dissected into two events: the calcium-independent microtubule-dependent translocation of granules to the plasma membrane and calcium-dependent membrane fusion and exocytosis. Finally, we show that the Fyn/Gab2/RhoA (but not Lyn/SLP-76) signaling pathway plays a critical role in the calcium-independent microtubule-dependent pathway

    Evaluation for effect of hypothermia on the disposition of 4-nitrophenol in rats by in-vitro metabolism study and rat liver perfusion system

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    Objectives The aim of this study was to evaluate the effect of hypothermia on the in-vivo pharmacokinetics of 4-nitrophenol (4NP) using rat liver homogenate and rat liver perfusion system. Methods Rat liver homogenate was incubated with 4NP, which is mainly metabolized by cytochrome P450 2E1, at 37, 34, 32 or 28°C. The Michaelis constant (Km) and maximum elimination velocity (Vmax) of 4NP were calculated by a Hanes-Woolf plot. The hepatic extraction ratio (Eh) of 4NP was evaluated in a rat liver perfusion study at 37, 34, 32 or 28°C. Moreover, the plasma concentration profiles of 4NP after its intravenous (i.v.) administration to rats were analysed by the moment theory and were compared with in-vitro parameters. Key findings While the Km of 4NP was not changed, the Vmax and Eh were reduced at low temperatures. The plasma concentrations of 4NP after its i.v. administration to rats were significantly increased at 28°C. Conclusion Changes in the pharmacokinetics of 4NP under hypothermic conditions were caused by alterations in Vmax and E h. We may be able to predict the disposition of a drug by in-vitro studies
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