ß-Delayed One and Two Neutron Emission Probabilities Southeast of

The ß-delayed one- and two-neutron emission probabilities (P_{1n} and P_{2n}) of 20 neutron-rich nuclei with N≥82 have been measured at the RIBF facility of the RIKEN Nishina Center. P_{1n} of ^{130,131}Ag, ^{133,134}Cd, ^{135,136}In, and ^{138,139}Sn were determined for the first time, and stringent upper limits were placed on P_{2n} for nearly all cases. ß-delayed two-neutron emission (ß2n) was unambiguously identified in ^{133}Cd and ^{135,136}In, and their P_{2n} were measured. Weak ß2n was also detected from ^{137,138}Sn. Our results highlight the effect of the N=82 and Z=50 shell closures on ß-delayed neutron emission probability and provide stringent benchmarks for newly developed macroscopic-microscopic and self-consistent global models with the inclusion of a statistical treatment of neutron and γ emission. The impact of our measurements on r-process nucleosynthesis was studied in a neutron star merger scenario. Our P_{1n} and P_{2n} have a direct impact on the odd-even staggering of the final abundance, improving the agreement between calculated and observed Solar System abundances. The odd isotope fraction of Ba in r-process-enhanced (r-II) stars is also better reproduced using our new data.

Evidence for a new nuclear 'magic number' from the level structure of 54Ca.

Atomic nuclei are finite quantum systems composed of two distinct types of fermion--protons and neutrons. In a manner similar to that of electrons orbiting in an atom, protons and neutrons in a nucleus form shell structures. In the case of stable, naturally occurring nuclei, large energy gaps exist between shells that fill completely when the proton or neutron number is equal to 2, 8, 20, 28, 50, 82 or 126 (ref. 1). Away from stability, however, these so-called 'magic numbers' are known to evolve in systems with a large imbalance of protons and neutrons. Although some of the standard shell closures can disappear, new ones are known to appear. Studies aiming to identify and understand such behaviour are of major importance in the field of experimental and theoretical nuclear physics. Here we report a spectroscopic study of the neutron-rich nucleus (54)Ca (a bound system composed of 20 protons and 34 neutrons) using proton knockout reactions involving fast radioactive projectiles. The results highlight the doubly magic nature of (54)Ca and provide direct experimental evidence for the onset of a sizable subshell closure at neutron number 34 in isotopes far from stability.

Diagnosing eosinophilic asthma using a multivariate prediction model based on blood granulocyte responsiveness.

BACKGROUND: The identification of inflammatory asthma phenotypes, using sputum analysis, has proven its value in diagnosis and disease monitoring. However due to technical limitations of sputum analysis, there is a strong need for fast and noninvasive diagnostics. This study included the activation state of eosinophils and neutrophils in peripheral blood to phenotype and monitor asthma. OBJECTIVES: To (i) construct a multivariable model using the activation state of blood granulocytes, (ii) compare its diagnostic value with sputum eosinophilia as gold standard and (iii) validate the model in an independent patient cohort. METHODS: Clinical parameters, activation of blood granulocytes and sputum characteristics were assessed in 115 adult patients with asthma (training cohort/Utrecht) and 34 patients (validation cohort/Oxford). RESULTS: The combination of blood eosinophil count, fractional exhaled nitric oxide, Asthma Control Questionnaire, medication use, nasal polyposis, aspirin sensitivity and neutrophil/eosinophil responsiveness upon stimulation with formyl-methionyl-leucyl phenylalanine was found to identify sputum eosinophilia with 90.5% sensitivity and 91.5% specificity in the training cohort and with 77% sensitivity and 71% specificity in the validation cohort (relatively high percentage on oral corticosteroids [OCS]). CONCLUSIONS: The proposed prediction model identifies eosinophilic asthma without the need for sputum induction. The model forms a noninvasive and externally validated test to assess eosinophilic asthma in patients not on OCS.

Decays of the Three Top Contributors to the Reactor ν[over ¯]_{e} High-Energy Spectrum,

We report total absorption spectroscopy measurements of ^{92}Rb, ^{96gs}Y, and ^{142}Cs ß decays, which are the most important contributors to the high energy ν[over ¯]_{e} spectral shape in nuclear reactors. These three ß decays contribute 43% of the ν[over ¯]_{e} flux near 5.5 MeV emitted by nuclear reactors. This ν[over ¯]_{e} energy is particularly interesting due to spectral features recently observed in several experiments including the Daya Bay, Double Chooz, and RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory by means of proton-induced fission of ^{238}U with on-line mass separation of fission fragments and the Modular Total Absorption Spectrometer. We observe a ß-decay pattern that is similar to recent measurements of ^{92}Rb, with a ground-state to ground-state ß feeding of 91(3)%. We verify the ^{96gs}Y ground-state to ground-state ß feeding of 95.5(20)%. Our measurements substantially modify the ß-decay feedings of ^{142}Cs, reducing the ß feeding to ^{142}Ba states below 2 MeV by 32% when compared with the latest evaluations. Our results increase the discrepancy between the observed and the expected reactor ν[over ¯]_{e} flux between 5 and 7 MeV, the maximum excess increases from ∼10% to ∼12%.

Candidate Resonant Tetraneutron State Populated by the

A candidate resonant tetraneutron state is found in the missing-mass spectrum obtained in the double-charge-exchange reaction ^{4}He(^{8}He,^{8}Be) at 186 MeV/u. The energy of the state is 0.83±0.65(stat)±1.25(syst) MeV above the threshold of four-neutron decay with a significance level of 4.9σ. Utilizing the large positive Q value of the (^{8}He,^{8}Be) reaction, an almost recoilless condition of the four-neutron system was achieved so as to obtain a weakly interacting four-neutron system efficiently.

Low-Lying Structure of (50)Ar and the N=32 Subshell Closure.

The low-lying structure of the neutron-rich nucleus (50)Ar has been investigated at the Radioactive Isotope Beam Factory using in-beam γ-ray spectroscopy with (9)Be((54)Ca,(50)Ar+γ)X, (9)Be((55)Sc,(50)Ar+γ)X, and (9)Be((56)Ti,(50)Ar+γ)X multinucleon removal reactions at ∼220 MeV/u. A γ-ray peak at 1178(18) keV is reported and assigned as the transition from the first 2(+) state to the 0(+) ground state. A weaker, tentative line at 1582(38) keV is suggested as the 4(1)(+)→2(1)(+) transition. The experimental results are compared to large-scale shell-model calculations performed in the sdpf model space using the SDPF-MU effective interaction with modifications based on recent experimental data for exotic calcium and potassium isotopes. The modified Hamiltonian provides a satisfactory description of the new experimental results for (50)Ar and, more generally, reproduces the energy systematics of low-lying states in neutron-rich Ar isotopes rather well. The shell-model calculations indicate that the N=32 subshell gap in (50)Ar is similar in magnitude to those in (52)Ca and (54)Ti and, notably, predict an N=34 subshell closure in (52)Ar that is larger than the one recently reported in (54)Ca.

The prognostic impact of the neutrophil-to-lymphocyte ratio in patients with small-cell lung cancer.

BACKGROUND: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are prognostic factors for various types of cancer. In this study, we assessed the association of NLR and PLR with the prognosis of small-cell lung cancer (SCLC) in patients who received the standard treatment. METHODS: We retrospectively reviewed patients who were diagnosed with SCLC and treated with platinum-based chemotherapy between July 2006 and October 2013 in Gyeongsang National University Hospital Regional Cancer Center and Changwon Samsung Hospital. RESULTS: In total, 187 patients were evaluated. Compared with low NLR (<4), high NLR (⩾4) at diagnosis was associated with poor performance status, advanced stage, and lower response rate. Median overall survival (OS) and progression-free survival (PFS) were worse in the high-NLR group (high vs low, 11.17 vs 9.20 months, P=0.019 and 6.90 vs 5.49 months, P=0.005, respectively). In contrast, PLR at diagnosis was not associated with OS or PFS (P=0.467 and P=0.205, respectively). In multivariate analysis, stage, lactate dehydrogenase, and NLR at diagnosis were independent prognostic factors for OS and PFS. CONCLUSIONS: NLR is easily measurable and reflects the SCLC prognosis. A future prospective study is warranted to confirm our results.

Isomer decay spectroscopy of 164Sm and 166Gd: midshell collectivity around N=100.

Excited states in the N=102 isotones 166Gd and 164Sm have been observed following isomeric decay for the first time at RIBF, RIKEN. The half-lives of the isomeric states have been measured to be 950(60) and 600(140) ns for 166Gd and 164Sm, respectively. Based on the decay patterns and potential energy surface calculations, including ß6 deformation, a spin and parity of 6- has been assigned to the isomeric states in both nuclei. Collective observables are discussed in light of the systematics of the region, giving insight into nuclear shape evolution. The decrease in the ground-band energies of 166Gd and 164Sm (N=102) compared to 164Gd and 162Sm (N=100), respectively, presents evidence for the predicted deformed shell closure at N=100.

Demonstration of nuclear gamma-ray polarimetry based on a multi-layer CdTe Compton camera.

To detect and track structural changes in atomic nuclei, the systematic study of nuclear levels with firm spin-parity assignments is important. While linear polarization measurements have been applied to determine the electromagnetic character of gamma-ray transitions, the applicable range is strongly limited due to the low efficiency of the detection system. The multi-layer Cadmium-Telluride (CdTe) Compton camera can be a state-of-the-art gamma-ray polarimeter for nuclear spectroscopy with the high position sensitivity and the detection efficiency. We demonstrated the capability to operate this detector as a reliable gamma-ray polarimeter by using polarized 847-keV gamma rays produced by the [Formula: see text]([Formula: see text]) reaction. By combining the experimental data and simulated calculations, the modulation curve for the gamma ray was successfully obtained. A remarkably high polarization sensitivity was achieved, compatible with a reasonable detection efficiency. Based on the obtained results, a possible future gamma-ray polarimetery is discussed.

Initial phase establishment of an in vitro method for developmental neurotoxicity test using Ki-67 in human neural progenitor cells.

Building a precise alternative neurotoxicological test is of great importance to respond to societal and ethical requirements. In this study, a new developmental neurotoxicity test (DNT) was established with the human neural progenitor cell line. ReNcell CX cells were exposed to neurotoxic chemicals (aphidicolin, hydroxyurea, cytosine arabinoside, 5-fluorouracil, and ochratoxin A) or non-neurotoxic chemicals (sodium gluconate, sodium bicarbonate, penicillin G, and saccharin). Propidium iodide (PI) was used to evaluate cell viability. BrdU and Ki-76 were employed to determine cell proliferation. Based on the cell viability and proliferation, mathematical models were built by linear discriminant analysis. Furthermore, the neurotoxic-considered chemicals inhibited cell cycle progression at the protein level, supporting the biomolecular rationale for the predictive model. Overall, these results show that the new test method can be used to determine the potential developmental neurotoxicants or new drug candidates.

Well developed deformation in 42Si.

Excited states in (38,40,42) Si nuclei have been studied via in-beam γ-ray spectroscopy with multinucleon removal reactions. Intense radioactive beams of ^{40}S and (44)S provided at the new facility of the RIKEN Radioactive Isotope Beam Factory enabled γ-γ coincidence measurements. A prominent γ line observed with an energy of 742(8) keV in (42) Si confirms the 2(+) state reported in an earlier study. Among the γ lines observed in coincidence with the 2^{+} → 0+ transition, the most probable candidate for the transition from the yrast 4(+) state was identified, leading to a 4(1)+) energy of 2173(14) keV. The energy ratio of 2.93(5) between the 2(1)+ and 4(1)(+) states indicates well-developed deformation in (42) Si at N = 28 and Z = 14. Also for 38,40)Si energy ratios with values of 2.09(5) and 2.56(5) were obtained. Together with the ratio for (42)Si, the results show a rapid deformation development of Si isotopes from N = 24 to N = 28.

ß-decay half-lives of very neutron-rich Kr to Tc isotopes on the boundary of the r-process path: an indication of fast r-matter flow.

The ß-decay half-lives of 38 neutron-rich isotopes from (36)Kr to (43)Tc have been measured; the half-lives of (100)Kr, (103-105)Sr, (106-108)Y, (108-110)Zr, (111,112)Nb, (112-115)Mo, and (116,117)Tc are reported here. The results when compared with previous standard models indicate an overestimation in the predicted half-lives by a factor of 2 or more in the A≈110 region. A revised model based on the second generation gross theory of ß decay better predicts the measured half-lives and suggests a more rapid flow of the rapid neutron-capture process (r-matter flow) through this region than previously predicted.

Structural evolution in the neutron-rich nuclei ¹°6Zr and ¹°8Zr.

The low-lying states in ¹°6Zr and ¹°8Zr have been investigated by means of ß-γ and isomer spectroscopy at the radioactive isotope beam factory (RIBF), respectively. A new isomer with a half-life of 620 ± 150 ns has been identified in ¹°8Zr. For the sequence of even-even Zr isotopes, the excitation energies of the first 2⁺ states reach a minimum at N = 64 and gradually increase as the neutron number increases up to N = 68, suggesting a deformed subshell closure at N = 64. The deformed ground state of ¹°8Zr indicates that a spherical subshell gap predicted at N = 70 is not large enough to change the ground state of ¹°8Zr to the spherical shape. The possibility of a tetrahedral shape isomer in ¹°8Zr is also discussed.

Distribution of mast-cell precursors in hematopoeitic and lymphopoietic tissues of mice.

Two experimental systems were used to investigate the origin of precursor cells which differentiate into tissue mast cells in vivo. (a) Increase of mast cell number was examined in the skin, stomach, cecum, and mesentery of genetically mast cell-depleted WBB6F1 (WB X C57BL/6)-W/WV mice after the injection of various hematolymphoid cells of congenic +/+ mice. (b) Appearance of mast cells with giant granules was studied in irradiated C57BL/6-+/+ mice after the injection of lymphoid cells of C57BL/6-bgJ/bgJ (beige, Chediak-Higashi syndrome) mice. Concentrations of mast cell precursors in the thymus, lymph node and Peyer's patch were less than 0.1% of the concentration in the bone marrow. Neither treatment of donor bone marrow cells with anti-Thy-1.2 serum and complement nor thymectomy of the recipient mice affects the development of mast cells in the skin, stomach, cecum, and mesentery. Moreover, the number of mast cells increased to normal level when the skin of WBB6F1-W/WV mice was grafted on the back of nude athymic (BALB/c-nu/nu) mice. These results indicate that mast cell precursors are derived from hematopoietic tissues rather than lymphopoetic ones and that the differentiation of the precursor cells does not depend on T lymphocytes or the thymus.

Neuroendocrine-immune modulation may be useful for allograft-specific immunosuppression in small bowel transplantation.

PURPOSE: The authors have previously demonstrated that the neuropeptide bombesin (BBS) prevented allograft mucosal atrophy under tacrolimus (TRL) immunosuppression for rats small bowel transplantation (SBT). The present study investigated whether BBS had immunosuppressive effects on small bowel allografts. METHODS: Allogeneic SBT was performed heterotopically in rats (n = 12) that received daily administration of 0.1 mg/kg/d TRL from postoperative day 0 to day 14. Rats divided into two groups of six rats each were administered BBS or normal saline as a control. Biopsy of the allograft was performed from the stomal site on postoperative days 6, 10, and 14. The state of the graft mucosal villi was evaluated by H & E staining and TUNEL immunohistochemistry. RESULTS: By postoperative day 14, extensive mucosal destruction accompanied by heavy transmural cellular infiltration had developed in the control group. Lymphocytes and plasma cells infiltrated the lamina propria of the allograft without the distorting villous architecture in the BBS group. The TUNEL index of graft mucosa in the control group was 1.26% +/- 0.37% (mean +/- SD) and that in the BBS group, 0.59% +/- 0.20%, respectively (p < .001). CONCLUSION: This study demonstrated an immunosuppressive effect of bombesin on transplanted allografts, which might dramatically reduce the dose of TRL required for postoperative immunosuppression.

Equilibrium folding intermediates of a Greek key beta-barrel protein.

Protein S is a calcium-binding protein comprising two Greek key beta-barrel domains. We have used NMR and optical spectroscopies to show that, in the absence of calcium, the N-terminal domain of protein S forms two equilibrium folding intermediates that are in slow exchange. The intermediates arise from differential calcium-dependent folding of subdomains which are not contiguous along the polypeptide chain. The structures of these intermediates are incompatible with several previously proposed folding mechanisms for Greek key beta-barrel domains. We proposed a different mechanism that involves multiple nucleation sites for folding and sequential acquisition of native long-range interactions.

Structural studies of soluble oligomers of the Alzheimer beta-amyloid peptide.

Recent studies have suggested that non-fibrillar soluble forms of Abeta peptides possess neurotoxic properties and may therefore play a role in the molecular pathogenesis of Alzheimer's disease. We have identified solution conditions under which two types of soluble oligomers of Abeta40 could be trapped and stabilized for an extended period of time. The first type of oligomers comprises a mixture of dimers/tetramers which are stable at neutral pH and low micromolar concentration, for a period of at least four weeks. The second type of oligomer comprises a narrow distribution of particles that are spherical when examined by electron microscopy and atomic force microscopy. The number average molecular mass of this distribution of particles is 0.94 MDa, and they are are stable at pH 3 for at least four weeks. Circular dichroism studies indicate that the dimers/tetramers possess irregular secondary structure that is not alpha-helix or beta-structure, while the 0.94 MDa particles contain beta-structure. Fluorescence resonance energy transfer experiments indicate that Abeta40 moieties in amyloid fibrils or protofibrils are more similar in structure to those in the 0.94 MDa particles than those in the dimers/tetramers. These findings indicate that soluble oligomeric forms of Abeta peptides can be trapped for extended periods of time, enabling their study by high resolution techniques that would not otherwise be possible.

Effects of castration and testosterone administration on serum lipoproteins and their apoproteins in male spontaneously hypertensive rat.

Serum triglyceride and very low density lipoprotein (VLDL) concentrations were higher in male spontaneously hypertensive rat than in male control Wistar Kyoto rat, whereas serum cholesterol, phospholipids, and high density lipoprotein (HDL) concentrations were lower. Castration of hypertensive rats induced an increase in serum cholesterol, phospholipids, and HDL, and a decrease in serum triglyceride and VLDL. The cholesterol content of HDL increased, whereas the triglycerides decreased after gonadectomy of hypertensive rats. These changes in serum lipids and lipoproteins could be reversed by the administration of testosterone. Apolipoprotein E contents in VLDL and HDL of hypertensive rats were low when compared with control rats but rose after castration and could be reduced by testosterone administration. Hypertensive rats accumulated triglycerides and cholesterol in the liver, which resulted in an increase of liver weight. Castration reduced the hepatic lipids as well as liver weight. The effects of castration and testosterone treatment on lipids and lipoproteins were more prominent in spontaneously hypertensive rats than in control rats. These results suggest that testosterone reduces VLDL catabolism which is related to changes of apolipoprotein composition, and that hypertensive rats are more sensitive to testosterone than control rats.

The storage form of human renal renin.

We isolated renin granules from cadaver kidneys using discontinuous sucrose density gradient centrifugation, and investigated the storage form of the renin from these granules. Approximately 23% of the total renin activity in the original homogenate was obtained from the surface phase between 1.6 and 1.7 M sucrose (Fraction 6). Granule renin extracted from the granules in Fraction 6 was separated into active and inactive renin using pepstatin affinity chromatography. Only the active renin had an affinity for pepstatin. The inactive renin, albeit activated by trypsin, was little activated by acidification. The proportion of inactive renin was about 25% of the total granule renin (active renin + inactive renin). Trypsin concentrations over 10 micrograms/ml resulted in a decrease in the renin activity of the trypsin-activated renin, but the enzymatic activity of active renin was decreased by trypsin. With gel filtration, the inactive renin revealed a single peak, and the molecular weight (MW) was 48,000. The active renin had a MW of 44,000. The inactive renin could be activated by trypsin without an apparent change in molecular weight.

Implications of quantitative tumor and nodal regression rates for nasopharyngeal carcinomas after 45 Gy of radiotherapy.

PURPOSE: To quantitatively investigate the clinical implications of tumor regression rate (TRR-45) and nodal regression rate (NRR-45) of nasopharyngeal carcinomas (NPC) after receiving 45 Gy of radiotherapy (RT). The values, predictive values, and associated factors of TRR-45 and NRR-45 in NPC are analyzed. METHODS AND MATERIALS: One hundred one patients with newly diagnosed NPC and who were curatively treated by RT alone were included in the study. Tumor volume and nodal volume before treatment and after 45 Gy were obtained from computed tomographic (CT) scans performed at those times and calculated with the assistance of a computer-based imaging analyzing system. TRR-45 (NRR-45) was defined as the ratio of reduced tumor (nodal) volume after 45 Gy to the initial tumor (nodal) volume. TRR-45 (NRR-45) values were stratified into three groups of slow (below 50%), moderate (between 50% and 75%), and rapid (above 75%) change. After conventional RT with 45 Gy, conformal RT for primary tumors was boosted to 70.2-72 Gy for T1-2 tumors, and 75.6-81 Gy for T3-T4 tumors. RT for residual neck masses was boosted by electron beam to 61-75 Gy. RESULTS: The mean value of TRR-45 for all patients was lower than that of NRR-45 for the 78 patients with metastatic neck nodes (70% +/- 4.8% vs. 81% +/- 5%, p = 0.003). The 3-year actuarial neck control rate was better than the primary tumor control rate with statistical significance (98% vs. 85%, p = 0.009). No significant statistical differences concerning local control probability, nodal control probability, or survival rate were found among patients with slow, moderate, or rapid TRR-45 or NRR-45. T-stage was the only significant prognostic factor for locoregional control after multivariate analysis. Tumor volume and T-stage were found to have a statistically significant negative correlation with TRR-45. No associated factor was found to be significantly correlated with NRR-45. CONCLUSION: Slow regression rates of the primary tumor or neck nodes in NPC after receiving 45 Gy of irradiation do not mean ultimately poor radiocurability, but may merely imply slow clearance of the cells damaged during irradiation. The different radiobiological behaviors of the regression rates during treatment, ultimate control probabilities, or associated factors for regression rates of NPC between primary tumors and neck nodes need to be further investigated.