74 research outputs found

    Kerr-lens mode-locked Tm^3+:Sc_2O_3 single-crystal laser in-band pumped by an Er:Yb fiber MOPA at 1611  nm

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    We demonstrate a Kerr-lens mode-locked Tm3+:Sc2O3single-crystal laser in-band pumped by an Er3+:Yb3+ fiber master oscillator power amplifier at 1611 nm. Pulses as short as 166 fs with an average output power of 440 mW are obtained. The spectral bandwidth and center wavelength are 29.3 and 2124 nm, respectively. At a longer pulse duration of 298 fs, we obtain 1 W of average output power. The repetition rate is 95 MHz, and the conversion efficiency against the absorbed pump power is as high as 47%. To the best of our knowledge, this is the first Kerr-lens mode-locked Tm3+-doped solid state laser

    Discovery and informing research participants of incidental findings detected in brain magnetic resonance imaging studies : Review and multi‐institutional study

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    Background: Brain imaging studies using magnetic resonance imaging (MRI ) sometimes reveal incidental findings (IFs) that might be relevant to some of the health issues in research participants. Although professional communities have discussed how to manage these IFs, there is no global consensus on the concrete handling procedures including how to inform participants of IFs. Methods: First, this study reviewed previous studies for the number of IFs discovered in brain imaging studies using MEDLINE. Second, a multi‐institutional study determined the number of IF discoveries and evaluated the method of informing participants at multiple institutions, which participated in a national brain science project in Japan. Results: Both the review and multi‐institutional study showed that IFs with a high urgency level were discovered in 0–2.0% of participants, including healthy volunteers, and that the rate of IF discovery in general was higher in studies conducted in elderly population. Moreover, multi‐institutional study suggested the criteria used to judge whether or not to inform participants of IFs may differ by institution. Conclusions: Our results suggest that in order to ensure informing the participants of high urgency IFs, physicians who are capable of interpreting brain images clinically should review all brain images, and the establishment of a support system is required for brain imaging studies at nonmedical institutions. Since the method of informing participants of IFs might affect their understanding and acceptance of IFs, which are related to managing risks of false “clean bill of health” or psychological impacts of informing IFs, further research focusing on communication of IFs is needed

    1994 Multi-site Broadband Seismic Observation at Sakurajima Volcano, Japan

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    Broadband observation of volcanic earthquakes has been recently conducted at many volcanoes. At the Sakurajima Volcano in Japan, one of the most active volcanoes all over the world, we conducted two broadband seismic observations successfully in last three years. However, they left some problems in terms of the number of observation sites and recording systems. This paper reports the outline of our third observation using three broadband seismometers (Streckeisen STS-II) with continuous recording at the Sakurajima Volcano from February 18 to March 28, 1994. This observation is distinguished from the previous two by the three stations operating continuously over the entire period. Although the Sakurajima Volcano had very low seismic activities during this observation period, we observed some kinds of volcanic earthquake, A-type and B-type earthquakes and volcanic tremors, particularly one series of interesting clone events

    Intrinsic and scattering attenuation of the Mt Fuji Region, Japan

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    Mount Fuji is the focus of intense study because of its potential hazard signaled by seismic, geologic and historical activity. Based on extensive seismic data recorded in the vicinity of Mt Fuji, coda quality factor () using a single scattering model hypothesis, and intrinsic and scattering quality factor ( and ) using the Multiple Lapse Time Window (MLTW) method were measured. To focus the study on the magmatic structure below Mt Fuji, the data were separated into two groups: a near-Fuji region of rays traversing an area with radius 5 km around the summit ( 20 km). This classification shows the largest discrepancy of at a range of sampling volumes corresponding to overlapped sampling depth of about 80 km. Further, the spatial division shows significant difference of and at hypocentral distance of 80 km. The large difference of in bandwidths 2–4, and 4–8 Hz indicates lithospheric heterogeneity beneath Mt Fuji with a characteristic heterogeneity scale length of about 1 km. The results have a small error range due to the large data sample, showing that all values in the near-Fuji area are greater than those of the far-Fuji area, and for both the near and far-Fuji areas is higher than at high frequencies. The and values for far-Fuji are in the range of values for typical non-volcanic areas. The values of the near-Fuji area are lower than those of other volcanic areas considered, where as values of are not. The low for the volcanic region of near-Fuji suggests that the magmatic activity, indicated by percent partial melt, in the vicinity of Mt Fuji is not as active as hot spot volcanoes, such as Kilauea, Hawaii

    alpha-lipoic acid suppresses 6-hydroxydoparnine-induced ROS generation and apoptosis through the stimulation of glutathione synthesis but not by the expression of heme oxygenase-1

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    We previously reported that the generation of reactive oxygen species (ROS) is the initial event in cell death induced by 6-hydroxydopamine (6-OHDA), an experimental model of Parkinsonism. Since recent studies suggested the important role of antioxidant activity of alpha-lipoic acid (LA) in the suppression of apoptosis of various types, we studied the effect on 6-OHDA-induced apoptosis of PC12 cells. Biochemical analysis revealed that LA suppressed the 6-OHDA-induced ROS generation, increase of caspase-like activity and chromatin condensation. The suppression of 6-OHDA-induced apoptosis by LA required pre-incubation of PC12 cells with LA for 12-24 h. LA increased the intracellular levels of heme oxygenase-1 (HO-1) and glutathione (GSH) and stimulated the expression of GSH synthesis-related genes such as cystine/glutamate antiporter and gamma-glutamylcysteine synthetase (gamma-GCS). However, Sn-mesoporphyrin IX, an inhibitor of HO-1, did not attenuate the LA-induced suppression of apoptosis. In contrast, buthionine sulfoximine, an inhibitor of gamma-GCS, attenuated the LA-induced suppression of ROS generation and chromatin condensation. in addition, a transcription factor Nrf2, which regulates the expression of antioxidant enzymes such as gamma-GCS, translocated to the nucleus by LA. These results suggested that LA suppressed the 6-OHDA induced-apoptosis by the increase in cellular glutathione through stimulation of the GSH synthesis system but not by the expression of HO-1.</p

    Beliefs held by breast surgeons that impact the treatment decision process for advanced breast cancer patients : a qualitative study

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    Introduction: Although guidelines do not recommend chemotherapy for patients with advanced cancer when death is imminent, many reports suggest the tendency to continue this treatment has been increasing every year. This study aimed to construct a model to clarify the beliefs and communication of doctors who administer chemotherapy to patients with recurrent or metastatic (hereafter, “recurrent/metastatic”) breast cancer, and determine how these beliefs are related to the process of treating patients. Materials and methods: Semi-structured interviews were conducted with 21 breast surgeons, and interview contents were analyzed using the grounded theory approach in order to conceptualize the treatment process. Results: The process of chemotherapy for patients with recurrent/metastatic breast cancer differed based on two beliefs held by doctors. One was a “belief that the patient is an entity who cannot accept death,” and throughout the treatment process, these doctors consistently avoided sharing bad news that might hurt patients, and always discussed aggressive chemotherapy. They proposed treatments as long as options remained, and when they ultimately judged that the physical condition of patients could not withstand further treatment, treatment was terminated despite the patient hoping for continuation. The other was a “belief that the patient is an entity who can accept death.” From early on after recurrence/metastasis, these doctors repeatedly gave patients information including bad news about prognosis, and when they judged that further treatment would hinder a patient’s ability to have a good death, they proposed terminating treatment. Conclusion: We demonstrated that breast surgeons treating recurrent/metastatic breast cancer patients have two beliefs and constructed a model of the treatment process based on those beliefs. This offered breast surgeons, who make decisions regarding treatment without clearly-defined guidelines, a chance to reflect on their own care style, which we believe will contribute to optimal patient care

    The effect of three large Mw¿7.3 subduction earth-quakes (August-November 2012) on volcanic unrest in Central America

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    ¿Was the volcanic eruption triggered by the earthquake?¿ The answer to this question usually is ¿maybe¿ or ¿a coincidence¿. A region like Central America, is an adequate area to find hints to answer this question because have the necessary ingredients: the frequent occurrence of large earthquakes (M5+) and dozens of active volcanoes. This research focuses on whether the uncommon occurrence of three large earthquakes in the subduction zone of Central America, within a time span of ten weeks in 2012, promoted enhanced volcanic activity. The time window analyzed is from 2000 to 2019, which includes a total of 50 volcanic eruptions with a VEI¿2. Before the 2012 earthquakes, 22 eruptions occurred. The Monte Carlo statistical simulation method allowed to demonstrate that this increase in the number of volcanic eruptions after the three large earthquakes of 2012 it is not a temporal coincidence. We analyzed the characteristics of each earthquake and described how they could disturb the volcanic systems. Although Central America hosts 24 volcanoes with historical eruptions, only 11 of them erupted after the 2012 earthquakes. Why did only these volcanoes erupt? To answer this question, we calculated the dynamic and static stress in each volcano and the level of volcanic unrest (the change in volcanic activity beyond background behavior to worrisome levels) prior to the earthquakes. We found that volcanoes in a unrest stage before the earthquakes but, without experiencing explosive eruptions before, erupted after receiving the seismic shocks. This fact suggests that the earthquakes by themselves did not transfer enough energy to generate the volcanic eruptions when volcanoes were not ready to erupt. However, earthquakes could promote volcanic eruptions when volcanoes were already at unrest. This research offers a tool for forecasting volcanic activity when a large earthquake hits a region, if the volcanic activity is previously monitored

    Author Correction: Increment in the volcanic unrest and number of eruptions after the 2012 large earthquakes sequence in Central America

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    Correction to: Scientific Reports https://doi.org/10.1038/s41598-021-01725-1, published online 17 November 2021.The original version of this Article contained a repeated error in the Introduction, in Figure 1 and its accompanying legend, in the Results section under the subheading ‘Stress changes caused by the earthquakes’, in the Discussion and conclusions section under the subheading ‘Volcanic eruptions long after the earthquakes’, and in the Supplementary Information file, where the earthquake that occurred on November 7, 2012 was incorrectly mentioned as having occurred on November 11, 2012. The original Fig. 1 and accompanying legend appear below. The original Article and the Supplementary Information file that accompanies the original Article have been corrected.Peer reviewe
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