Experimental study on the bifurcation of a density oscillator depending on density difference

Hydrodynamic instabilities often cause spatio-temporal pattern formations and transitions between them. We investigate a model experimental system, a density oscillator, where the bifurcation from a resting state to an oscillatory state is triggered by the increase in the density difference of the two fluids. Our results show that the oscillation amplitude increases from zero and the period decreases above a critical density difference. The detailed data close to the bifurcation point provide a critical exponent consistent with the supercritical Hopf bifurcation.Comment: 7 pages, 7 figure

Immuno-serological and Electrophoretic Studies on the Protein of Pregnant Urin Part Ⅰ Immuno-serological Study on the Protein of Pregnant Urin

1. Rabbits were immunized repeatedly with the protein urin of pregnant toxikosis (pregnant edema, pregnant nephrosis, preeclampsia, eclampsia), inflammation of kidney and nephrosis. As the result of this experiment above, rabbits had antiserum with high precipitin titels. 2. Rabbits which were immunized repeatedly (ten times) with the protein urin of pregnant edema, pregnant nephrosis and inflammation of kidney could easily get antiserum with high precipitin titels but only few precipitin quantities, and showed no heterogitis. On the other side rabbits which were immunized repeatedly (ten times) with the protein urin of preeclampsia, eclampsia and nephrosis could easily get antiserum with high precipitin titels with the increase of the precipitin quantity, this time and show slightly higher heterogitis. Consequently, it was found that race-speciality is more intensive in the former than in the latter. 3. It was assumed from the data of the author and of other members in our department that if pregnant toxikosis turn to preeclampsia or eclampsia by getting worse, evacuation of a part of specific protein which had not been found before was found in adult serum

Microenvironment and radiation therapy

Dependency on tumor oxygenation is one of the major features of radiation therapy and this has led many radiation biologists and oncologists to focus on tumor hypoxia. The first approach to overcome tumor hypoxia was to improve tumor oxygenation by increasing oxygen delivery and a subsequent approach was the use of radiosensitizers in combination with radiation therapy. Clinical use of some of these approaches was promising, but they are not widely used due to several limitations. Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that is activated by hypoxia and induces the expression of various genes related to the adaptation of cellular metabolism to hypoxia, invasion and metastasis of cancer cells and angiogenesis, and so forth. HIF-1 is a potent target to enhance the therapeutic effects of radiation therapy. Another approach is antiangiogenic therapy. The combination with radiation therapy is promising, but several factors including surrogate markers, timing and duration, and so forth have to be optimized before introducing it into clinics. In this review, we examined how the tumor microenvironment influences the effects of radiation and how we can enhance the antitumor effects of radiation therapy by modifying the tumor microenvironment

Decreases in Brain Reward Function Reflect Nicotine- and Methamphetamine-Withdrawal Aversion in Rats

The purpose of the present study was to investigate whether brain reward function decreases during withdrawal from nicotine and methamphetamine, and whether decreased reward function is related to aversion during withdrawal from these drugs. For that purpose, male Sprague-Dawley rats were chronically infused subcutaneously with 9 mg/kg per day nicotine, or with 6 mg/kg per day methamphetamine using osmotic minipumps. In an intracranial self-stimulation (ICSS) paradigm, chronic infusion of nicotine and methamphetamine decreased the thresholds for lateral hypothalamic ICSS, whereas their antagonists, mecamylamine and haloperidol increased the ICSS thresholds in the rats treated with nicotine and methamphetamine, respectively. In a conditioned place aversion paradigm, mecamylamine and haloperidol produced place aversion in nicotine- and methamphetamine-infused rats, respectively. Interestingly, elevations in ICSS reward thresholds and place aversion during mecamylamine-precipitated nicotine withdrawal were almost the same in magnitude as those observed during haloperidol-precipitated methamphetamine withdrawal. The present study indicates that 1) brain reward function decreased during nicotine and methamphetamine withdrawal, and 2) a decrease in reward function may reflect the negative affective state (aversion) during withdrawal from nicotine and methamphetamine

High-frequency earthquake swarm associated with the May 1991 dome extrusion at Unzen Volcano, Japan

Abstract \nThe 1990-1995 eruption of Unzen Volcano in southwestern Japan was characterized by the extrusion of a dacite lava dome and frequent pyroclastic flows during the dome growth. Associated with the dome emergence on May 20, 1991, an intense swarm of high-frequency (HF) microearthquakes occurred just beneath the crater at very shallow depths. We used data from FG3, a seismic station located 500 m SSW of the crater, to identify 29,401 HF earthquakes between May 11 and 31, 1991. The rate of HF earthquakes increased starting on May 12 and peaked on May 17. The high seismicity continued until May 26, then dropped sharply, coinciding with a marked decline in the swelling on the southern upper flank of the volcano. The seismicity increased and decreased repeatedly within a 1- to 2-h period, which was correlated with tilt cycles observed 680 m west of the crater in such a way that the seismicity increased during uplifting on the craterward side. Defining an earthquake group as a series of earthquakes with waveforms that are similar or vary only slightly over time, we identified 10 such groups, each containing more than 300 events. The largest group comprised 3,214 events over 18 days. Seismicity rates of eight groups, including the largest, increased and decreased repeatedly, correlated with the tilt cycles. As the waveform data from station FG3 were considerably clipped for relatively large events, we analyzed data from two additional stations, KRA and CJA, located 3.5 and 8.7 km from the crater, respectively, and identified a total of five new groups. The activity of two groups recorded at KRA was correlated with the tilt cycles, but those of three groups recorded at CJA did not always show such a correlation. Hypocenters for the groups recorded at KRA were distributed to the east side of the conduit and a focal mechanism suggested that the events in this area occurred due to compressional stress produced by the inflation of the conduit. The groups recorded at CJA occurred to the north side of the dike trending westward from the conduit. The focal mechanisms have P-axes roughly trending to the dike, which can be explained by the compressional stress generated by the increasing thickness of the dike

Strategies for Reducing Blood Transfusions in Hepatic Resection

A comparison of 60 blood transfused and 71 nonblood transfused hepatic resection patients was done to evaluate strategies for reducing blood transfusions during hepatic surgery. There were no significant differences between the two groups with regard to preoperative laboratory data, except for prothrombin time and hematocrit value. The mean operative blood loss was 1990 ml and 760 ml in the blood transfused and nonblood transfused groups, respectively. A multivariate analysis suggested that the patient’s body weight, preoperative prothrombin time, and operative blood loss independently predicted the need for intraoperative blood transfusion. Major postoperative complications developed more frequently in the blood transfused group than in the nonblood transfused group (31.7 vs. 11.3%, p<0.005). These results suggest that the difference in operative blood loss between the two groups was related to the prolonged prothrombin time and a susceptibility for blood transfusion was found to exist particularly in patients with a lower hematocrit value as well as a lower body weight. Thus, the improvement of these preoperative laboratory data combined with avoiding the use of the hematocrit value as a determining factor for intraoperative transfusion could correspond to a reduction in operative blood loss, while curtailing the demands on blood bank facilities, and lowering the risk of postoperative complications

Initial Value Problem Formulation of 3-D Time Domain Boundary Element Method

A time domain boundary element method (TDBEM) gives us another possibility of time domain microwave simulations in addition to a finite difference time domain (FDTD) method. In particular, the TDBEM has good advantages in analysis of coupling problems with charged particle motion such as in a particle accelerator. However, it is known that time domain microwave simulations in the particle accelerator by the conventional TDBEM often encounter numerical instability and inaccuracy because of its bad matrix property. To avoid the numerical instability and inaccuracy caused by the conventional open boundary problem formulation of the TDBEM, an initial value problem formulation of 3-D TDBEM is presented in this paper