Calibration measurements for the efficiency and response functionof the NE213 scintillator by a 252Cf spontaneous fissionsource-application of a two-dimensional pulse height analysissystem

The authors describe calibration measurements for the efficiency and response function of the NE213 scintillator as an application of a two-dimensional pulse height analysis system. In this method, a ²⁵² Cf spontaneous fission source with a continuous spectrum is employed by taking each fission event as a pulsed neutron source, and the efficiency and response function of the NE213 scintillator can be estimated by two-dimensional measurements of the time-of-flight spectrum (neutron energy spectrum) and pulse height spectrum     

Negative-chirp electroabsorption modulator using low-wavelengthdetuning

The negative chirp of an electroabsorption modulator having an α-parameter value of 0 to -0.5, at an input light wavelength of 1.55-1.56 μm, has been developed by optimizing the bandgap energy of an InGaAsP bulk absorption layer. We have demonstrated successful transmission with 10 Gb/s NRZ modulation over a 100-km span of standard fiber without resort to dispersion compensation     

Isolation and characterization of two cDNAs encoding 4-coumarate:CoA ligase in Lithospermum cell cultures

Two near full-length cDNAs (LE4CL-1, LE4CL-2), which encode 4-coumarate:CoA ligase (4CL), were cloned from a library of Lithospermum erythrorhizon cell suspension cultures by the use of heterologous probe of potato 4CL. These cDNAs are 2.1 kb and 2.2 kb in length, respectively. LE4CL-1 encodes 636 amino acids, whose homologies to the 4CL protein sequences known to potato, parsley, pine and rice, were found to be 68%, 66%, 56% and 50% (identities on amino acid level), respectively, whereas those of the predicted translation product of LE4CL-2 (594 amino acids) to the above 4CL proteins were 49 approximately 54%. The similarity of the deduced amino acid sequences between the two 4CLs from Lithospermum cell cultures was 49% in identity. Northern analyses showed that the mRNA levels of both LE4CL-1 and LE4CL-2 were much higher under illumination than in the dark, as reported for the 4CL genes of such plants as parsley. In comparison of mRNA levels of LE4CL-1 and LE4CL-2, the former was demonstrated to be generally higher than the latter by means of an application of RT-PCR. The genomic southern blot experiments suggested that there are probably three copies of LE4CL-1 in the Lithospermum genome DNA, whereas only one copy was detected for LE4CL-2.     

Effect of pressure onT c in La2- x Ba x CuO4 withx=0.125

The superconducting transition temperature,T _c , of La_2?x Ba _x CuO₄ has been measured under high pressure up to 8 GPa.T _c is found to change drastically at the pressure where the structural phase transition takes place. This finding clearly indicates that there exists an intimate relation between the crystal structure and superconductivity.     

Estimating the time-delay and frequency decay parameter ofscattering components using a modified MUSIC algorithm

A superresolution technique to determine the time-delay and frequency response of individual components of electromagnetic scattering is presented. A modification of the MUltiple SIgnal Classification (MUSIC) algorithm is proposed for the data model which includes scattering components with frequency dependent amplitudes. The modified technique is based on pre-multiplying the scattering data by the inverse of an assumed frequency dependence parameterized by a variable α. Estimates of α are then obtained by considering the roots of the root-MUSIC polynomial for various α. The algorithm is tested for simulated and experimental compact range data. For the example of measured scattering from a diagonal flat plate, different decay parameters corresponding to the single and double diffraction components are determined using the new algorithm     

Transform-limited optical short-pulse generation at high repetitionrate over 40 GHz from a monolithic passive mode-locked DBR laser diode

The fabrication of monolithic InP-based passively mode-locked distributed-Bragg-reflector (DBR) laser is reported. An optical short-pulse train with a duration of 3.5 ps was generated at a repetition rate of over 40 GHz. The time-bandwidth product was 0.43, and it was very close to the transform-limited value of a Gaussian waveform. Peak power of 60 mW has been achieved. This laser is promising as an optical source for a high-bit-rate soliton transmission system     

Clinical significance of micromegakaryocytes in de novo AML

Bone marrow specimens obtained from 54 patients with de novo AML and 7 patients with AML evolving from MDS were retrospectively examined for the presence of micromegakaryocytes defined as cells of less than 30 microns in diameter with one or two nuclei. At least 25 megakaryocytes were counted in each patient. Micromegakaryocytes were found in 17 cases (31%), M1:1/11, M2:5/18, M3:0/4, M4:5/12, M5:1/4, M6:4/4, M7:1/1. The median age of the patients was higher in de novo AML with micromegakaryocytes (57 years) than in de novo AML without micromegakaryocytes (41 years) (p = 0.014). Chromosomal analysis revealed that deletion of 5 or 5q-, 7 or 7q- was recognized only in the group of de novo AML with micromegakaryocytes and that t(15;17), t(8:21) and inv (16) were not recognized in this group. Micromegakaryocytes were identified in each bone marrow specimen obtained from 9 of 10 patients with de novo AML with trilineage myelodysplasia. The complete remission rate was significantly lower in de novo AML with micromegakaryocytes (33%) than in de novo AML without micromegakaryocytes (86%) (p = 0.001). The duration of survival of the patients with de novo AML with micromegakaryocytes was shown to be shorter than that of the patients with de novo AML without micromegakaryocytes (p = 0.017). Micromegakaryocytes were recognized in all of 7 patients with AML evolving from MDS. The presence of micromegakaryocytes in bone marrow of the patients with AML indicates a subset of AML with poor prognosis that may be closely associated with myelodysplastic syndrome.     

Fibronectin expression in cancer tissues from patients undergoing radiation therapy

Fibronectin expression and distribution were examined in cancer tissues from 19 patients with cancer of the head and neck regions. Samples taken before and after irradiation of approximately 10 Gy, 20 Gy or 30 Gy were analyzed by the avidin-biotin-horseradish peroxidase method using mouse monoclonal antibodies against human fibronectin. The results were correlated with the patient's prognosis after radiation therapy. No remarkable changes in the fibronectin expression or distribution were found between tissue specimens taken before and after each dose of irradiation. The prognosis, however, varied according to the degree of expression and the distribution pattern of fibronectin. Seven patients in which the cancer tissue was encircled by a thick fibronectin network are still alive without recurrence 4.5-6 years after treatment, whereas 6 patients in which fibronectin was only faintly expressed or focally distributed died or developed recurrence soon after treatment. The present findings demonstrate that fibronectin expression and distribution in cancer tissue are intimately related to the patient's prognosis, and that the analysis of these two parameters is applicable as a predictive assay in radiotherapy of cancer of the head and neck regions.     

Surgical treatment of atrial fibrillation--experience with 9 cases

The patient was a 50-year-old alcoholic man with a left palatine tonsillar ulcer. Histopathological and bacteriological studies established the diagnosis of tonsillar tuberculosis with asymptomatic advanced pulmonary tuberculosis and multiple cerebral supra- and infratentorial tuberculomas previously unnoticed.