Search

We developed a CANDLES-III system to study the neutrino-less double beta (0$\nu\beta\beta$) decay of $^{48}$Ca. The proposed system employs 96 CaF$_{2}$ scintillation crystals (305 kg) with natural Ca ($^{\rm nat.}$Ca) isotope which corresponds 350\,g of $^{48}$Ca. External backgrounds were rejected using a 4$\pi$ active shield of a liquid scintillator surrounding the CaF$_2$ crystals. The internal backgrounds caused by the radioactive impurities within the CaF$_2$ crystals can be reduced effectively through analysis of the signal pulse shape. We analyzed the data obtained in the Kamioka underground for a live-time of 130.4\,days to evaluate the feasibility of the low background measurement with the CANDLES-III detector. Using Monte Carlo simulations, we estimated the background rate from the radioactive impurities in the CaF$_{2}$ crystals and the rate of high energy $\gamma$-rays caused by the (n, $\gamma$) reactions induced by environmental neutrons. The expected background rate was in a good agreement with the measured rate, i.e., approximately 10$^{-3}$ events/keV/yr/(kg of $^{\rm nat.}$Ca), in the 0$\nu\beta\beta$ window. In conclusion, the background candidates were estimated properly by comparing the measured energy spectrum with the background simulations. With this measurement method, we performed the first search for 0$\nu\beta\beta$ decay in a low background condition using a detector with a Ca isotope, in which the Ca present was not enriched, in a scale of hundreds of kg. The $^{48}$Ca isotope has a high potential for use in 0$\nu\beta\beta$ decay search, and is expected to be useful for the development of a next-generation detector for highly sensitive measurements.

High energy γ rays with several MeV produced by (n,γ) reactions can be a trouble for low background measurements in the underground laboratories such as double beta decay experiments. In the CANDLES project, which aimed to observe the neutrino-less double beta decay from 48Ca, γ rays caused by (n,γ) reactions were found to be the most significant background. The profile of the background was studied by measurements with a neutron source and a simulation with a validity check of neutron processes in Geant4. The observed spectrum of γ rays from (n,γ) reactions was well reproduced by the simulated spectra, which were originated from the surrounding rock and a detector tank made of stainless steel. The environmental neutron flux was derived by the observed event rate of γ rays from (n,γ) reactions using the simulation. The thermal and non-thermal neutron flux were found to be ( 1.3 ± 0.6 ) × 10 − 6 cm − 2 s − 1 and ( 1.1 ± 0.5 ) × 10 − 5 cm − 2 s − 1 , respectively. It is necessary to install an additional shield to reduce the background from (n,γ) reaction to the required level.

We have studied the neutrino-less double beta decay(0νββ) of 48Ca with the CANDLES III system, which consists of CaF2(pure) scintillators. Rejection analyses for background events from radioactive contaminations in the CaF2(pure) scintillators were effective to reduce backgrounds in Qββ -value region. As the results, no events were observed in the region for the data of 131 days × 86 kg. It gave a lower limit 6.2 × 1022 year (90 % C.L.) for the half-life of 0νββ of 48Ca. For higher sensitive measurement of 48Ca 0νββ, we have developed new techniques for 48Ca enrichment and CaF2 scintillating bolometer. In this paper, we will also show current status of these techniques.

The neutrino-less double beta decay is acquiring great interest after the confirmation of neutrino oscillation which demonstrated nonzero neutrino mass. In order to search for neutrino-less double beta decay of $^{48}$Ca, we proposed the CANDLES project by using CaF$_{2}$(pure) scintillators. Now we installed the CANDLES III system at the Kamioka underground laboratory. The CANDLES III system realizes the low background condition by a characteristic structure and data analyses for background rejection. Furthermore we installed new shielding system in order to reduce $\gamma$-ray backgrounds from neutron capture reaction. Here we report performances of the CANDLES III system.

CANDLES(CAlcium fluoride for the study of Neutrinos and Dark matters by Low Energy Spectrometer) is the experiment to search for the neutrino-less double beta decay(0vββ) of 48Ca with CaF2 scintillator. 48Ca has the highest Q ββ -value (4.3 MeV) among all isotope candidates for 0vββ. It enables us to measure signals with very low background condition. After rejection analysis with 131 days × 86 kg data for background events from radioactive contaminations in the CaF2 scintillators, no events are observed in the Q ββ -value region. As a result, the half-life of 48Ca is greater than 6.2 × 1022 yr (90% confidence level). For further high sensitive measurement of 48Ca 0vββ search, we have been developing the 48Ca enrichment and CaF2 scintillating bolometer techniques. In this paper, the latest result for CANDLES and the status of scintillating bolometer development are described.

We have studied the neutrino-less double beta decay(0νββ) of 48Ca by using CaF2(pure) scintillators. Analysis for rejection of backgrounds(212Bi→ 212Po events and 208Tl events) was effective to reduce backgrounds in Qββ-value region. No events are observed in the Qββ-value region for the data of 131 days × 86 kg. It gives a lower limit (90% confidence level) of (math) > 6.2 × 1022 year (preliminary) for the half-life of 0νββ of 48Ca.

For a supergoup \(\), we study closed \(\)-manifolds with positive conformal classes. We use the relative Yamabe invariant from [2] to define the conformal cobordism relation on the category of such manifolds. We prove that the corresponding conformal cobordism groups \(\) are isomorphic to the cobordism groups \(\) defined by Stolz in [19]. As a corollary, we show that the conformal concordance relation on positive conformal classes coincides with the standard concordance relation on positive scalar curvature metrics. Our main technical tools come from analysis and conformal geometry.

The direct ultraviolet irradiation of dimethyl benzyl phosphite (1) and dimethyl p-acetylbenzyl phosphite (8) was investigated in acetonitrile, cyclohexane, and benzene. Phosphite 1 gives predominantly the photo-Arbuzov product, dimethyl benzylphosphonate (2), in 67−81% accountability yields, based of phosphite consumed, along with minor amounts of bibenzyl (20) and dimethyl phosphite (10). The quantum yield for formation of 2 in cyclohexane, φP, is 0.43. By contrast, irradiation of phosphite 8 yields only 7−13% of photo-Arbuzov phosphonate (9) but relatively large amounts of radical diffusion products: dimethyl phosphite (10) the p-acetylbenzyl radical dimer (11); and p-acetyltoluene (12). Evidently 8, closely related to acetophenone, reacts predominantly via the triplet excited estate to generate long-lived, triplet, free-radical pairs (6 and 7a). In benzene, further products (15, 16, 17a and 17b) are identified that result from addition of the phosphinoyl radical (6) to benzene to give cyclohexadienyl...

A 3/7-level mixed-mode algorithmic analog-to- digital converter (ADC) is proposed. The operation comprises six phases to obtain the 8-bit resolution. The 3-level mode is used in the first three phases for an accurate conversion, while the 7-level mode is used for the last three phases to improve the sampling speed. Transistor-level simulations assuming 0.18-mum CMOS technology with a supply voltage of 1.8 V are carried out to estimate the circuit performance. A signal-to-noise ratio of 48.1dB (ap7.7 bit) is obtained at a sampling frequency of 12.8 MHz, which is superior to the results obtained from conventional 3-level and 7-level algorithmic ADCs.

We show that, for all nonnegative integers $k, l, m$ and $ n$, the Yamabe invariant of $$ \#(\mathbb{RP}^3)\# \ell(\mathbb{RP}^2 \#m(S^2 \times S^1)\#n(S^2 \tilde \times S^1)$$ is equal to the Yamabe invariant of $\mathbb{RP}^3$, provided $k + \ell \geq 1$. We then complete the classification (started by Bray and the second author) of all closed 3-manifolds with Yamabe invariant greater than that of $\mathbb{RP}^3$. More precisely, we show that such maniforlds are either $S^3$ or finite connected sums $ \# m (S^2 \times S^1) \# n (S^2 \tilde \times S^1)$, where $S^2 \tilde \times S^1$ is the nonorientable $S^2$-bundle over $S^1$. ¶ A key ingredient is Aubin’s Lemma [3], which says that if the Yamabe constant is positive, then it is strictly less than the Yamabe constant of any of its non-trivial finite conformal coverings. This lemma, combined with inverse mean curvature flow and with analysis of the Green’s function for the conformal Laplacians on specific finite and normal infinite Riemannian coverings, will al- low us to construct a family of nice test functions on the finite coverings and thus prove the desired result.

The authors describe the NIP-III image processor, which can execute a wide variety of general image processing operations for automobile industry manufacturing applications. Sixteen processing units having the same architecture are connected in rows. Individual users can input desired instructions to each unit and also freely change the bus lines linking the units. The processing units are implemented by gate-array large-scale integrated circuits and can perform the arithmetic and logic functions needed for image processing. A high processing speed has been achieved without increasing the size of the circuits. The authors present the hardware architecture of the NIP-III and describe its processing capabilities. >

Primitive neuroectodermal tumors (PNETs) are very rare. Malignant tumors of the cerebrum in young individuals are composed predominantly of undifferentiated cells, with moderate differentiation along either neuronal or glial lines. To our knowledge, cerebral PNETs in adults are extraordinarily rare and have been reported in only 11 cases, with little cytologic documentation in the literature. The cytopathologic, immunohistochemical and ultrastructural features of cerebral PNET arising in an adult male are presented.A cystic tumor, on computed tomography and magnetic resonance imaging, arose from the left frontal lobe in a 39-year-old man and contained histopathologic features of PNET. Specimens obtained from surgery revealed the presence of an undifferentiated type of PNET with moderate neuronal and glial differentiation and mild characteristic findings of peripheral PNET. The cytologic and histologic specimens showed evidence of a scattered pattern of blastic and undifferentiated tumor cells and a neural arrangement with Homer-Wright-like rosettes. Immunohistochemically, the tumor cells were glial fibrillary acidic protein, neuron-specific enolase, synaptophysin and CD-99 positive and epithelial membrane antigen, S-100 protein and vimentin negative. Ultrastructurally, neither microtubular structures nor intermediate filaments, except neurosecretory granules, were found in the tumor cells.Both immunohistochemical and ultrastructural studies on cytologic and histologic slides were important for the diagnosis of PNET because of establishing not only undifferentiated tumor cells but also neural and glial differentiation.

Management after heart transplantation must deal with the twin risks of rejection and infection. Early infection with viral infection, particularly cytomegalovirus (CMV), is becoming more prevalent two to three months after transplantation. To our knowledge, there has been no previous report of human polyomavirus (HPOV) infection after heart transplantation.A 20-year-old male with a history of Kawasaki disease and who had suffered from severe congestive heart failure after a coronary artery bypass graft, underwent heart transplantation. Urinary cytology demonstrated HPOV infection, the diagnosis of which was established by the immunoperoxidase technique, in situ hybridization and electron microscopy.The definitive diagnosis of HPOV infection after a heart transplant can be made on urinary cytology.

Allyl and benzyl phosphites undergo photoisomerization to the corresponding allyl- and benzylphosphonates. The triplet-sensitized photorearrangements of the allyl systems are regiospecific. A triplet 5-membered ring 1,3-phosphoranyl biradical intermediate is proposed. Optically active phosphites, chiral at the benzyl carbon, undergo intramolecular photo-Arbuzov rearrangement with very predominant retention of configuration at carbon.

Etude de la reduction du coefficient de frottement des composites a matrice metallique et d'une nouvelle methode de production de ces composes. Utilisation de la microscopie electronique a balayage pour caracteriser les etats de surface apres les tests d'usure

Allyl and benzyl phosphites undergo photoisomerization to the corresponding allyl- and benzylphosphonates. The triplet-sensitized photorearrangements of the allyl systems are regiospecific. A triplet 5-membered ring 1,3-phosphoranyl biradical intermediate is proposed. Optically active phosphites, chiral at the benzyl carbon, undergo intramolecular photo-Arbuzov rearrangement with very predominant retention of configuration at carbon.

Lithiation of the pyrrole (I) and subsequent treatment with CO2 (III) give the 1-pyrrolecarboxylate (IV) which undergoes further lithiation, followed by reaction with the electrophiles (V).

Effects of flurazepam, a benzodiazepine derivative, on Ca2+-induced cardio-stimulant contractile activity in normal Tyrode's solution and Ca2+-mediated contraction in K+-rich (19-22 mM) Tyrode's solution were investigated in electrically driven left atrial preparations isolated from guinea-pigs. In normal Tyrode's solution, flurazepam (1 X 10(-6), 1 X 10(-5) and 1 X 10(-4) M) noncompetitively shifted the dose-response curves for CaCl2 downwards. In K+ (19 mM)-rich Tyrode's solution, flurazepam (3 X 10(-5) M) decreased contractile amplitude time-dependently; and after addition of CaCl2 (final: 8 mM), contractile amplitude was increased time-dependently. In K+ (19 mM)-depolarized preparations, flurazepam (3 X 10(-5) M) competitively shifted the dose-response curve for CaCl2 rightwards. In the K+ (22 mM)-depolarized isoproterenol (3.8 X 10(-6) M)-treated atrial preparation, flurazepam (3 X 10(-5) M) consistently suppressed contraction. Flurazepam (9 X 10(-5) M) suppressed atrial contraction in tetrodotoxin (TTX) (2 X 10(-5) M)-added normal Tyrode's solution, and CaCl2 (final: 8 mM) partially restored the contraction. These results suggest that flurazepam inhibits transmembrane Ca2+-influx into the atrial muscle cell.