384 research outputs found
Planar hole-doping concentration and effective three-dimensional hole-doping concentration for single-layer high- superconductors
We propose that physical properties for the high temperature superconductors
can be addressed by either a two-dimensional planar hole-doping concentration
() or an effective three-dimentional hole-doping concentration
(). We find that superconducting transition temperature ()
exhibits a universal dome-shaped behavior in the plot with
a universal optimal doping concentration at 1.6
10 cm for the single-layer high temperature superconductors.Comment: 2pages, 2 figures, submitted to Physica C (Proceedings of M2S-HTSC
VIII) ; Ref. 10 is revise
Cytoskeletal elements in an acoelomorph worm, Praesagittifera naikaiensis
Acoel flatworms can move in a variety of ways such as muscular and ciliary movements via cytoskeletal elements and their neural regulations. However, those locomotive mechanisms have not yet been fully elucidated. In this study, we examined the distribution of cytoskeletal elements including filamentous actin (F-actin) and tubulin, and the neuroanatomical organization in an acoelomorph worm, Praesagittifera naikaiensis (P. naikaiensis). Video microscopy revealed the elongation/contraction and the bending/rotation processes, and the ciliary gliding movement of P. naikaiensis. Histochemical and morphological analysis demonstrated that F-actin networks of inner longitudinal and outer circular muscle fibers were positioned along the entire surface of the body, and that the average distance between the circular muscle fibers in the contracted organism was decreased in the anterior region compared with that in the elongated organism. Electron microscopy showed dense bodies on the muscle cells of P. naikaiensis, which indicates that those muscle cells have the appearance of vertebrate smooth muscle cells. Immunohistochemical analysis revealed that -tubulin-positive signals on the ciliary microtubules had close contact with the F-actin network, and that neurite bundles labelled with anti dSap47 antibody as a neuronal marker run along the anterior-posterior body axis. These results indicate that the well-organized cytoskeletal elements and their neural control systems are preserved in P. naikaiensis, and that their mechanisms involved in those regulation systems are similar to those vertebrate systems. Further studies are needed to clarify the physiological mechanisms underlying the muscular and ciliary movements in P. naikaiensis
High-resolution imaging of myosin motor in action by a high-speed atomic force microscope
金沢大学理学部The atomic force microscope (AFM) is a powerful tool for imaging biological molecules on a substrate, in solution. However, there is no effective time axis with AFM; commercially available AFMs require minutes to capture an image, but many interesting biological processes occur at much higher rate. Hence, what we can observe using the AFM is limited to stationary molecules, or those moving very slowly. We sought to increase markedly the scan speed of the AFM, so that in the future it can be used to study the dynamic behaviour of biomolecules. For this purpose, we have developed various devices optimised for high-speed scanning. Combining these devices has produced an AFM that can capture a 100 x 100 pixel image within 80 ms, thus generating a movie consisting of many successive images of a sample in aqueous solution. This is demonstrated by imaging myosin V molecules moving on mica, in solution
The prognostic effect of tumor volume, reduction ratio, and cumulative doses on external beam radiotherapy with central-shielding method and image-guided adaptive brachytherapy for cervical cancer
ObjectiveTo evaluate the prognostic effect of tumor volume at diagnosis, tumor reduction ratio during external beam radiotherapy (EBRT) with central-shielding method, and cumulative minimal dose to 90% of the high-risk clinical target volume (CTVHR D90) on combined EBRT and image-guided adaptive brachytherapy (IGABT) for cervical cancer.MethodsConsecutive patients who underwent definitive radiotherapy or concurrent chemoradiotherapy for cervical cancer at Gunma University Hospital between January 2010 and December 2019 were retrospectively reviewed. Tumor volume at diagnosis and reduction ratio were calculated using magnetic resonance imaging at diagnosis and before the first IGABT session. The cumulative dose of EBRT and IGABT was calculated as an equivalent dose in 2 Gy fractions (EQD2). Optimal cutoff values were determined according to a receiver operating characteristic curve. Treatment outcomes were evaluated using the Kaplan–Meier method and compared using the log-rank test and Cox proportional hazards regression.ResultsA total of 254 patients were included in the analysis. The median follow-up for all patients was 57 (2–134) months. The 5-year overall survival (OS) was 81.9%, progression-free survival (PFS) was 71.3%, and local control (LC) was 94.5%. The patients were divided into four groups according to tumor volume at diagnosis and reduction ratio. The group with tumor volume at diagnosis ≥ 34.1 cm3 and reduction ratio < 68.8% showed significantly worse OS, PFS, and LC than the other three groups (All p < 0.05). In this group, the patients with a cumulative CTVHR D90 < 69.6 GyEQD2 showed significantly worse PFS and LC (p = 0.042 and p = 0.027, respectively). In the multivariate analysis of OS, adenocarcinoma/adenosquamous carcinoma, International Federation of Gynecology and Obstetrics 2009 stage III/IV, and a reduction ratio of < 68.8% were independent significant poor prognostic factors (p = 0.045, p = 0.009 and p = 0.001, respectively). In the univariate analysis of LC, a reduction ratio of < 68.8% was the only poor prognostic factor (p = 0.041).ConclusionThe patients with large and poorly responding tumors had significantly worse prognoses in terms of OS, PFS, and LC, suggesting that dose escalation should be considered for such tumors
JASTRO IC/IS Guideline for Gynecologic Cancers
It has been postulated that the combination of intracavitary and interstitial brachytherapy (IC/IS) is effective and safe for large and irregularly shaped uterine cervical cancer patients. However, due to its invasiveness compared to conventional intracavitary brachytherapy (ICBT), it has to be said that the implementation speed of IC/IS is slow. Until now, there have been no guidelines for required equipment, human resources, and procedural guide focusing solely on IC/IS. The purpose of this guideline is to provide radiation oncologists and medical physicists who wish to start IC/IS with practical and comprehensive guidance for a safe IC/IS introduction and to help accelerate the spread of the utilization of IC/IS nationwide. This is the English translation of the Japanese IC/IS Guidelines, and it was created in an effort to share the Japanese approach to the management of locally advanced uterine cervical cancer worldwide
Embedded DRAM using c-axis-aligned crystalline In-Ga-Zn oxide FET with 1.8V-power-supply voltage
An embedded memory using c-axis aligned crystalline In-Ga-Zn oxide (CAAC-IGZO) FETs with an extremely low off-state current on the order of yoctoamperes (yA) (yocto- is a metric prefix denoting a factor of 10-24) is known as a potential next-generation memory [1][2]. A dynamic oxide semiconductor RAM (DOSRAM), where each memory cell is composed of one CAAC-IGZO FET and one capacitor, enables long data retention and long interval of refresh operations with an advantage of extremely low off-state current of the CAAC-IGZO FET. However, negative backgate voltage (Vbg) and word-line driving voltages of 0/3.3 V (VSSL/VDDH) had been required for an access transistor of the memory cell to satisfy high on-state current and low off-state current.
This work shows that DOSRAM operates with 1.8 V-power supply voltage by using a novel driving method.
Figure 1 shows Vg-Id performance of a CAAC-IGZO FET used as a cell transistor. The threshold voltage (Vth) of the CAAC-IGZO FET is controlled by changing a level of Vbg, whereas Vth of the Si FET is controlled by channel doping. Figure 2 shows a block diagram of a prototyped DOSRAM. The refresh rate in DOSRAM mainly depends on the leakage current of cell transistors. To reduce the refresh rate to once an hour, the off-state current of the cell transistors on a non-selected word line needs to be reduced to 200 zeptoamperes (zA) per FET (zepto- is a metric prefix denoting a factor of 10-21) or lower at 85C. The required Vbg is -7.0 V to achieve such an off-state current at Vg 0 V, for example. To obtain approx. 100 MHz-driving frequency, the required on-state current is at least several microamperes. The voltage level difference in the word line, VDDH VSSL, is a factor that determines the on-state current, and in this work is fixed to 3.3 V so that the combination of Vbg and the word line voltage is optimized. The application of negative voltage to the word line enables the leakage current of the cell transistor to be maintained low even when Vbg is increased. For example, whereas the existing driving method meets the above off-state current value with Vbg -7.0 V and the VSSL 0 V, the novel driving method meets the value with Vbg 0 V and VSSL -1.5 V. In the novel driving method, VDDH 1.8 V. There has been a report of a reduction in leakage current of a memory cell by application of negative voltage to a top gate in DRAM using Si CMOS [3]. In contrast to it, DOSRAM including CAAC-IGZO FETs with L 60 nm has a leakage current of 200 zA or lower, which is 7-digit lower than that of the DRAM using Si CMOS, and enables longer data retention.
The evaluation results of the prototyped DOSRAM verify that a reduction in power-supply voltage from 3.3 V to 1.8 V is possible in terms of operation and data retention. This suggests a highly compatible and efficient configuration of an embedded DRAM and a logic circuit where signals can be transmitted with low VDD.
References
[1] S. H. Wu, et al., IEEE Symp. VLSI Tech., pp. 166-167, 2017.
[2] T. Ishizu, et al., IEEE Symp. VLSI Cir., pp. 162-163, 2017.
[3] F. Hamzaoglu et al., IEEE Journal of Solid-State Circuits, vol. 50, no. 1, pp. 150-157, Jan. 2015
Characteristics of unique endocytosis induced by weak current for cytoplasmic drug delivery
We previously reported that 20 a weak current (WC, 0.3-0.5mA/cm2) applied to cells can induce endocytosis to promote cytoplasmic delivery of hydrophilic macromolecules (MW: < 70,000), such as dextran and siRNA, which leak from WC-induced endosomes into the cytoplasm (Hasan et al., 2016). In this study, we evaluated the characteristics of WC-mediated endocytosis for application of the technology to cytoplasmic delivery of macromolecular medicines. WC induced significantly higher cellular uptake of exogenous DNA fragments compared to untreated cells; the amount increased in a time-dependent manner, indicating that endocytosis was induced after WC. Moreover, following WC treatment of cells in the presence of an antibody (MW: 150,000) with the lysosomotropic agent chloroquine, the antibody was able to bind to its intracellular target. Thus, high molecular weight protein medicines delivered by WC-mediated endocytosis were functional in the cytoplasm. Transmission electron microscopy of cells treated by WC in the presence of gold nanoparticles covered with polyethylene glycol showed that the WC-induced endosomes exhibited an elliptical shape. In the WC-induced endosomes, ceramide, which makes pore structures in the membrane, was localized. Together, these results suggest that WC can induce unique endocytosis and that macromolecular medicines leak from endosomes through a ceramide pore
Hybrid Brachytherapy of Cervical Cancer
High-dose-rate brachytherapy by remote afterloading is now performed under three-dimensional image guidance by CT or MRI. Three-dimensional image-guided brachytherapy in cervical cancer disclosed that the traditional intracavitary brachytherapy by Manchester method cannot deliver an adequate dose to the large tumor with resulting local recurrence. To improve the local control rate, combined interstitial and intracavitary (hybrid) brachytherapy can increase the dose to the large parametrial involvement without increasing the dose to the rectum and bladder. Whether hybrid brachytherapy can be performed safely on a multi-institutional basis remains to be studied. From 2015, phase I/II study of hybrid brachytherapy was launched in Japan, and it was revealed that hybrid brachytherapy can be performed safely and with a high quality of radiation dose distribution in a multi-institutional study. In Japan, the number of patients undergoing hybrid brachytherapy in cervical cancer is rapidly rising. Education and clinical trial are very important to establish hybrid brachytherapy in the management of cervical cancer
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