Overview of the KEKB accelerators Kurokawa, S.; Kikutani, E.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2003, Letnik:
499, Številka:
1
Journal Article
Recenzirano
An overview of the KEKB accelerators is given as an introduction of the following articles in this issue, first by summarizing the basic features of the machines, and then describing the improvements ...of the performance since the start of the physics experiment.
The single-antenna gain calibration method was first proposed by Glimm et al. of Physikalisch-Technische Bundesanstalt in 1999. Their method requires the measurements of the reflection coefficient of ...an antenna under test (AUT) in free space and the reflection coefficient on a large metal plane using two different measurement setups. On the other hand, we proposed a new single-antenna gain calibration method that can measure these quantities using the same measurement setup. Our proposed method uses the average value of the reflection coefficients of the AUT for various distances from the large metal plane to the AUT. Furthermore, we established a measurement setup for our proposed single-antenna method for a double-ridged guide horn (DRGH) antenna in the frequency range from 1 to 6 GHz. To estimate the antenna gain, we applied the Friis transmission formula, which included the amplitude center distance of the antenna. By using our proposed method and the measurement setup, the expanded uncertainty (<inline-formula> <tex-math notation="LaTeX">k = 2 </tex-math></inline-formula>) of the DRGH was estimated to be from 0.61 to 1.70 dB over a frequency range from 1 to 6 GHz.
Functions of layilin, a type 1 transmembrane protein with a C-type lectin motif, remain to be clarified. We here investigated precise intracellular localization of layilin and the location-related ...functions.
We used HEK293T cells to assess the co-localization of layilin with different individual organelle markers by double immunostaining. We then investigated mitochondrial morphology in layilin-knockdown (KD) conditions, also with immunostaining. Next, we measured amounts of proteins involved in regulation of mitochondrial dynamics, DRP1, pS616-DRP1, mitofusin1, mitofusin2, CDK1, pY15-CDK1, and cyclin B1, in layilin-KD cells versus control cells by Western blot. Furthermore, by using layilin-knockout (KO) cells, amounts of CDK1 and pY15-CDK1 as well as mitochondrial morphology were investigated.
We found that layilin localized to mitochondria rather than the other organelles. Small round-shape mitochondria were observed in control cells, whereas elongated and highly connected mitochondria were observed in layilin-KD cells. Amounts of active DRP1 (pS616-DRP1) and total DRP1 were significantly smaller in layilin-KD cells than in controls. Amounts of inactive CDK1 (pY15-CDK1) were significantly larger in layilin-KD cells than in controls. No other tested molecules were significantly altered in layilin-KD cells. Amounts of inactive CDK1 were significantly larger in layilin-KO cells than in wild type (WT) cells. Small round-shape mitochondria were observed in WT cells, whereas elongated and highly connected mitochondria were observed in layilin-KO cells.
We here demonstrated that layilin played a role in the maintenance of fragmented mitochondria in mitochondrial dynamics and that this function needed CDK1 and DRP1 activation. Our data unveiled a novel function for layilin, regulation of mitochondrial dynamics.
•Layilin localizes to mitochondria rather than the other organelles.•Layilin plays a role in the maintenance of fragmented mitochondria in mitochondrial dynamics.•Layilin activates DRP1 through the activation of CDK1.
Recently, it has been reported that frequent premature ventricular contractions (PVCs) may be associated with causing heart failure in patients with left ventricular (LV) dysfunction. However, the ...prognostic significance of frequent PVCs in asymptomatic patients with a normal LV function is unclear.
Two hundred and thirty-nine consecutive patients presenting with frequent PVCs (>1000 beats/day) originating from the right or left ventricular outflow tract without any detectable heart disease were enrolled in the study. Structural heart disease was ruled out by echocardiography and cardiac magnetic resonance imaging, and Holter-ECG monitoring was repeated two or three times to evaluate the PVC prevalence at the initial evaluation. All patients were followed up for at least 4 years, and further observation was continued if possible.
During an observation period of 5.6 (1.7) years, no patients exhibited any serious cardiac events. Although there was no significant change in the mean LV ejection fraction (LVEF) and mean LV diastolic dimension (LVDd), there was a significant negative correlation between the PVC prevalence and DeltaLVEF (p<0.001) and positive correlation between the PVC prevalence and DeltaLVDd (p<0.001). When the development of LV dysfunction was defined as DeltaLVEF>-6%, 13 patients exhibited LV dysfunction. For the prediction of the development of LV dysfunction, PVC prevalence and LVEF at the initial evaluation were independent predicting factors (p<0.01).
Although the prognosis in patients with frequent PVCs was considered relatively benign, attention should be paid to the progression of the LV dysfunction during a long-term observation, especially in patients with a high PVC prevalence.
The authors propose a new non-destructive inspection method for underground fiberglass-reinforced plastic mortar (FRPM) pipelines. Their method utilises time-domain responses of microwave ...guided-modes propagating along an FRPM pipe-wall. Through the time-domain analyses, they found that a microwave guided-mode signal propagating along a pipe-wall is spread out to various waves corresponding to straight and circumferential waves along the pipe-wall and that the position of an unwanted foreign object on the wall can be detected by examining the path of the wave interrupted by the foreign object. Additionally, they also derived a propagation equation that enables them to calculate a time-domain response of the spread microwave guided-mode signals propagating along the pipe-wall. This method can be applied to pipelines consisting of various types of materials.
Recently, it has been reported that hypoxia highly enhances expression of peptidylarginine deiminase (PAD) 4 and production of citrullinated proteins in some tumor cells. However, little is known ...about malignant gliomas on this issue. Therefore, we here investigated whether expression of PADs was induced by hypoxia and whether PADs citrullinated intracellular proteins if induced using U-251 MG cells of a human malignant glioma cell line.
Expression of PADs in U-251 MG cells, cultured under hypoxia or normoxia for 24 h, was investigated by quantitative polymerase chain reaction (qPCR). Citrullination of proteins in the cells and the cell lysates incubated for 48 h with or without Ca2+ was detected by western blotting. Citrullinated proteins were identified by mass spectrometry.
The mRNA levels of PAD1, 2, 3, and 4 were up-regulated by hypoxia in a hypoxia-inducible factor-1-dependent manner in U-251 MG cells. In spite of the increased expression, intracellular proteins were not citrullinated. However, the induced PADs citrullinated U-251 MG cell-derived proteins when the cells were lysed. Multiple proteins citrullinated by hypoxia-induced PADs were identified. In addition, the extracellular domain of vascular endothelial growth factor receptor 2 was citrullinated by human PAD2 in vitro.
Our data may contribute to understanding of pathophysiology of malignant gliomas from the aspects of protein citrullination.
•Peptidylarginine deiminases (PADs) were induced by hypoxia in malignant glioma cells.•PADs mRNA levels were up-regulated in a HIF-1-dependent manner.•The induced PADs citrullinated the cell-derived proteins when tested in the lysates.•Multiple proteins citrullinated by hypoxia-induced PADs were identified.•An extracellular domain of VEGFR2 was citrullinated by human PAD2.
•Malignant glioma cells highly expressed layilin, compared to astrocytes.•Layilin was mainly localized in the cytoplasm of A172 and T98G cells.•Layilin up-regulated SNAI1 to increase expression of ...MMP2, MMP9 and COL1A1.•Transcription of SNAI1 was up-regulated via down-regulation of MTA3 by layilin.•Layilin enhanced the invasive ability of malignant glioma cells.
Malignant gliomas are characterized by high invasive ability. In this study, we investigated roles of layilin, a C-type lectin-homologous protein, in the invasive ability of malignant glioma cells.
Expression of layilin was investigated by western blotting in the malignant glioma cell lines of U251-MG, A172, and T98G and in astrocytes. The effects of layilin-knockdown on the expression and protein levels of snail family transcriptional repressor 1 (SNAI1), a transcriptional factor involved in the acquisition and enhancement of invasive ability in malignant gliomas, and on the expression of its target genes, matrix metalloproteinase 2 (MMP2), MMP9, and collagen type I alpha 1 chain (COL1A1), were investigated by qPCR and/or western blotting. Furthermore, the effects of layilin-knockdown on the expression and protein levels of metastasis associated 1 family member 3 (MTA3), a transcriptional repressor of SNAI1, were also investigated by qPCR and western blotting. Finally, the effects of layilin-knockdown on the invasive ability of the cells were investigated by a wound healing assay.
All the tested malignant glioma cells highly expressed layilin, compared to astrocytes, one of representative glial cell types. Layilin-knockdown reduced SNAI1 both at the mRNA and protein levels in A172 cells, and consequently mRNA levels of MMP2, MMP9, and COL1A1 were also reduced. Furthermore, layilin-knockdown increased nuclear protein levels of MTA3 in A172 cells. Notably, layilin-knockdown suppressed the invasive ability of the cells.
Layilin up-regulates the expression of SNAI1 via down-regulation of MTA3. This process enhances the invasive ability of malignant glioma cells.
This study investigated whether the specific motor control strategy reported for eccentric muscle actions is dependent on muscle mechanical behavior. Motor evoked potentials, Hoffman reflex ...(H-reflex), fascicle length, pennation angle, and fascicle velocity of soleus muscle were compared between isometric and two eccentric conditions. Ten volunteers performed maximal plantarflexion trials in isometric, slow eccentric (25°/s), and fast eccentric (100°/s) conditions, each in a different randomized testing session. H-reflex normalized by the preceding M wave (H/M) was depressed in both eccentric conditions compared with isometric ( P < 0.001), while no differences in fascicle length and pennation angle were found among conditions. Furthermore, although the fast eccentric condition had greater fascicle velocity than slow eccentric ( P = 0.001), there were no differences in H/M. There were no differences in motor evoked potential size between conditions, and silent period was shorter for both eccentric conditions compared with isometric ( P = 0.009). Taken together, the present results corroborate the hypothesis that the central nervous system has an unique activation strategy during eccentric muscle actions and suggest that sensory feedback does not play an important role in modulating these muscle actions. NEW & NOTEWORTHY The present study provides new insight into the motor control of eccentric muscle actions. It was demonstrated that task-dependent corticospinal excitability modulation does not seem to depend on sensory information processing. These findings support the hypothesis that the central nervous system has a unique activation strategy during eccentric muscle actions.
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