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Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10-21 s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28O and 27O through their decay into 24O and four and three neutrons, respectively. The 28O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers1,2, it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called 'doubly magic' nuclei. Both 27O and 28O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28O from a 29F beam is consistent with it not exhibiting a closed N = 20 shell structure.
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To search for low-energy resonant structures in isospin T=3/2 three-body systems, we have performed the experiments ^{3}H(t,^{3}He)3n and ^{3}He(^{3}He,t)3p at intermediate energies. For the 3n experiment, we have newly developed a thick Ti-^{3}H target that has the largest tritium thickness among targets of this type ever made. The 3n experiment for the first time covered the momentum-transfer region as low as 15 MeV/c, which provides ideal conditions for producing fragile systems. However, in the excitation-energy spectra we obtained, we did not observe any distinct peak structures. This is in sharp contrast to tetraneutron spectra. The distributions of the 3n and 3p spectra are found to be similar, except for the displacement in energy due to Coulomb repulsion. Comparisons with theoretical calculations suggest that three-body correlations exist in the 3n and 3p systems, although not enough to produce a resonant peak.
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Testing the limits of survivability in space is the primary focus in astrobiological research. Although a number of previous studies have examined terrestrial life survival in an extraterrestrial environment, only a few have investigated how life systems respond to high doses of alpha cosmic ray, the main component of cosmic rays. We used respiration and photosynthetic rates as indicators of the vital signs of the lichen Caloplaca flavovirescens, which is a symbiotic life form including fungi and algae. Our experiment demonstrated that the photosynthetic rate decreased with increased helium-beam doses, whereas the respiration rate was relatively unaffected. Specifically, under a helium-beam dose greater than 10 Gy, the respiration rate remained nearly constant regardless of further increases in the radiation rate. Our results indicate that the different metabolic systems of terrestrial life forms might exhibit different survival characteristics when they are in space.
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Radiación Cósmica , Relación Dosis-Respuesta en la Radiación , Líquenes/efectos de la radiación , Exobiología , Medio Ambiente Extraterrestre , Helio , Líquenes/fisiología , Fotosíntesis , Fenómenos FísicosRESUMEN
The objective of this study was to evaluate the effects of feeding purple corn (Zea mays L.) silage on productivity and blood superoxide dismutase concentration in lactating cows. We hypothesized that feeding purple corn silage (AX-152; Nagano Animal Industry Experiment Station, Nagano, Japan, and Takii and Co. Ltd., Tokyo, Japan), which is high in anthocyanin content, would increase milk production and blood concentration of superoxide dismutase. We assigned 16 Holstein cows (8 primiparous and 8 multiparous) in mid lactation to 1 of 2 treatments in a randomized block design, with efforts to balance parity, body weight, and days in milk between treatments. Experimental diets contained either purple corn silage [PCS; 31.2% dry matter (DM), 8.4% crude protein, 40.2% neutral detergent fiber, and 26.6% starch] or conventional corn silage (CONT; 30.5% dry matter, 8.7% crude protein, 42.1% neutral detergent fiber, and 26.5% starch) at approximately 32% of diet DM. Both PCS and CONT were ensiled for 5 mo before the study. Treatment diets were fed as total mixed rations ad libitum for 12 wk from February 1 to April 25, 2016. Cows fed the PCS had increased milk yield (31.7 vs. 29.2 kg/d) and blood superoxide dismutase concentrations (9,333 vs. 8,467 U/mL) compared with those fed CONT. However, anthocyanin concentration in the PCS decreased over the 12-wk experiment: 70 mg/kg of DM for the first 4 wk, 20 mg/kg of DM for the second 4 wk, and undetectable for the last 4 wk. We did not detect anthocyanins in the CONT group at any time point. Feeding PCS may increase antioxidant capacity and milk production in dairy cows, but anthocyanin in PCS may be degraded during storage.
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Bovinos/fisiología , Lactancia/efectos de los fármacos , Leche/metabolismo , Ensilaje/análisis , Superóxido Dismutasa/sangre , Animales , Antocianinas/metabolismo , Antioxidantes/metabolismo , Peso Corporal , Dieta/veterinaria , Fibras de la Dieta , Femenino , Japón , Estrés Oxidativo , Paridad , Embarazo , Almidón , Superóxido Dismutasa/metabolismo , Zea maysRESUMEN
The (^{12}N, ^{12}C) charge-exchange reaction at 175 MeV/u was developed as a novel probe for studying the isovector spin giant monopole resonance (IVSMR), whose properties are important for better understanding the bulk properties of nuclei and asymmetric nuclear matter. This probe, now available through the production of ^{12}N as a secondary rare-isotope beam, is exothermic, is strongly absorbed at the surface of the target nucleus, and provides selectivity for spin-transfer excitations. All three properties enhance the excitation of the IVSMR compared to other, primarily light-ion, probes, which have been used to study the IVSMR thus far. The ^{90}Zr(^{12}N,^{12}C) reaction was measured and the excitation energy spectra up to about 70 MeV for both the spin-transfer and non-spin-transfer channels were deduced separately by tagging the decay by γ emission from the ^{12}C ejectile. Besides the well-known Gamow-Teller and isobaric analog transitions, a clear signature of the IVSMR was identified. By comparing with the results from light-ion reactions on the same target nucleus and theoretical predictions, the suitability of this new probe for studying the IVSMR was confirmed.
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We observed the atomic 1s and 2p states of π^{-} bound to ^{121}Sn nuclei as distinct peak structures in the missing mass spectra of the ^{122}Sn(d,^{3}He) nuclear reaction. A very intense deuteron beam and a spectrometer with a large angular acceptance let us achieve a potential of discovery, which includes the capability of determining the angle-dependent cross sections with high statistics. The 2p state in a Sn nucleus was observed for the first time. The binding energies and widths of the pionic states are determined and found to be consistent with previous experimental results of other Sn isotopes. The spectrum is measured at finite reaction angles for the first time. The formation cross sections at the reaction angles between 0° and 2° are determined. The observed reaction-angle dependence of each state is reproduced by theoretical calculations. However, the quantitative comparison with our high-precision data reveals a significant discrepancy between the measured and calculated formation cross sections of the pionic 1s state.
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The gamma strength function and level density of 1^{-} states in ^{96}Mo have been extracted from a high-resolution study of the (p[over â], p[over â]^{'}) reaction at 295 MeV and extreme forward angles. By comparison with compound nucleus γ decay experiments, this allows a test of the generalized Brink-Axel hypothesis in the energy region of the pygmy dipole resonance. The Brink-Axel hypothesis is commonly assumed in astrophysical reaction network calculations and states that the gamma strength function in nuclei is independent of the structure of the initial and final state. The present results validate the Brink-Axel hypothesis for ^{96}Mo and provide independent confirmation of the methods used to separate gamma strength function and level density in γ decay experiments.
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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.
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BACKGROUND: Epidemiological evidence has demonstrated a clear association between diabetes mellitus and increased risk of Alzheimer's disease (AD). Cerebral accumulation of phosphorylated tau aggregates, a cardinal neuropathological feature of AD, is associated with neurodegeneration and cognitive decline. Clinical and experimental studies indicate that diabetes mellitus affects the development of tau pathology; however, the underlying molecular mechanisms remain unknown. OBJECTIVE: In the present study, we used a unique diabetic AD mouse model to investigate the changes in tau phosphorylation patterns occurring in the diabetic brain. DESIGN: Tau-transgenic mice were fed a high-fat diet (n = 24) to model diabetes mellitus. These mice developed prominent obesity, severe insulin resistance, and mild hyperglycemia, which led to early-onset neurodegeneration and behavioral impairment associated with the accumulation of hyperphosphorylated tau aggregates. RESULTS: Comprehensive phosphoproteomic analysis revealed a unique tau phosphorylation signature in the brains of mice with diabetic AD. Bioinformatic analysis of the phosphoproteomics data revealed putative tau-related kinases and cell signaling pathways involved in the interaction between diabetes mellitus and AD. CONCLUSION: These findings offer potential novel targets that can be used to develop tau-based therapies and biomarkers for use in AD.
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Enfermedad de Alzheimer , Disfunción Cognitiva , Diabetes Mellitus Tipo 2 , Ratones , Humanos , Animales , Enfermedad de Alzheimer/metabolismo , Proteínas tau/metabolismo , Fosforilación , Dieta Alta en Grasa/efectos adversos , Modelos Animales de Enfermedad , Ratones Transgénicos , Disfunción Cognitiva/complicacionesRESUMEN
We report on model studies of stimulated LâH transitions. These studies use a novel reduced mesoscale model. Studies reveal that LâH transitions can be triggered by particle injection into a subcritical state (i.e., P
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The double-differential cross sections for the (208)Pb and (90)Zr(t,(3)He) reactions at 300 MeV/u have been measured at the RI Beam Factory at RIKEN. This was the first physics experiment with the SHARAQ magnetic spectrometer. The combined analysis of the present (t,(3)He) data and previous (n,p) data provides the clearest identification for the ß(+) isovector spin monopole resonance both in the (208)Tl and (90)Y nuclei, and puts the observations of this giant resonance on a firm foundation. The measured distributions of the (t,(3)He) monopole cross sections were well reproduced by the distorted-wave Born approximation calculation, where the target transition density was calculated with the self-consistent Hartree-Fock plus random-phase approximation using the T43 Skyrme interaction. A major part of the expected ß(+) isovector spin monopole strength was found in the measured cross section spectra.
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Atrophic gastritis, intestinal metaplasia, and epithelial dysplasia of the stomach are common and are associated with an increased risk for gastric cancer. In the absence of guidelines, there is wide disparity in the management of patients with these premalignant conditions. The European Society of Gastrointestinal Endoscopy (ESGE), the European Helicobacter Study Group (EHSG), the European Society of Pathology (ESP) and the Sociedade Portuguesa de Endoscopia Digestiva (SPED) have therefore combined efforts to develop evidence-based guidelines on the management of patients with precancerous conditions and lesions of the stomach (termed MAPS). A multidisciplinary group of 63 experts from 24 countries developed these recommendations by means of repeat online voting and a meeting in June 2011 in Porto, Portugal. The recommendations emphasize the increased cancer risk in patients with gastric atrophy and metaplasia, and the need for adequate staging in the case of high grade dysplasia, and they focus on treatment and surveillance indications and methods.
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Mucosa Gástrica/patología , Gastritis Atrófica/patología , Gastritis Atrófica/terapia , Lesiones Precancerosas/patología , Lesiones Precancerosas/terapia , Neoplasias Gástricas/patología , Biopsia , Medicina Basada en la Evidencia , Gastritis Atrófica/diagnóstico , Gastroscopía , Infecciones por Helicobacter/tratamiento farmacológico , Infecciones por Helicobacter/economía , Infecciones por Helicobacter/microbiología , Helicobacter pylori , Humanos , Metaplasia/patología , Metaplasia/terapia , Pepsinógenos/sangre , Vigilancia de la Población , Lesiones Precancerosas/diagnósticoRESUMEN
BACKGROUND AND OBJECTIVE: Adiponectin is a cytokine constitutively produced by adipocytes and exhibits multiple biological functions by targeting various cell types. However, the effects of adiponectin on primary gingival fibroblasts and periodontal ligament cells are still unexplored. Therefore, we investigated the effects of adiponectin on gingival fibroblasts and periodontal ligament cells. MATERIAL AND METHODS: The expression of adiponectin receptors (AdipoR1 and AdipoR2) on human gingival fibroblasts (HGFs), mouse gingival fibroblasts (MGFs) and human periodontal ligament (HPDL) cells was examined using RT-PCR and western blotting. HGFs and MGFs were stimulated with interleukin (IL)-1ß in the presence or absence of adiponectin, and the expression of IL-6 and IL-8 at both mRNA and protein levels was measured by real-time PCR and ELISA, respectively. Furthermore, small interfering RNAs (siRNAs) in MGFs were used to knock down the expression of mouse AdipoR1 and AdipoR2. The effects of adiponectin on the expression of alkaline phosphatase (ALP) and runt-related transcription factor 2 (Runx2) genes were evaluated by real-time PCR. Mineralized nodule formation of adiponectin-treated HPDL cells was revealed by Alizarin Red staining. RESULTS: AdipoR1 and AdipoR2 were expressed constitutively in HGFs, MGFs and HPDL cells. Adiponectin decreased the expression of IL-6 and IL-8 in IL-1ß-stimulated HGFs and MGFs. AdipoR1 siRNA in MGFs revealed that the effect of adiponectin on reduction of IL-6 expression was potentially mediated via AdipoR1. Adiponectin-treated HPDL cells promoted the expression of ALP and Runx2 mRNAs and up-regulated ALP activity. Furthermore, adiponectin enhanced mineralized nodule formation of HPDL cells. CONCLUSION: Our observations demonstrate that adiponectin exerts anti-inflammatory effects on HGFs and MGFs, and promotes the activities of osteoblastogenesis of HPDL cells. We conclude that adiponectin has potent beneficial functions to maintain the homeostasis of periodontal health, improve periodontal lesions, and contribute to wound healing and tissue regeneration.
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Adiponectina/farmacología , Fibroblastos/efectos de los fármacos , Encía/efectos de los fármacos , Ligamento Periodontal/efectos de los fármacos , Fosfatasa Alcalina/análisis , Animales , Antraquinonas , Antiinflamatorios/farmacología , Calcificación Fisiológica/efectos de los fármacos , Técnicas de Cultivo de Célula , Diferenciación Celular/efectos de los fármacos , Línea Celular , Colorantes , Subunidad alfa 1 del Factor de Unión al Sitio Principal/análisis , Silenciador del Gen , Encía/citología , Humanos , Interleucina-1beta/farmacología , Interleucina-6/análisis , Interleucina-8/análisis , Interleucina-8/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Osteoblastos/efectos de los fármacos , Ligamento Periodontal/citología , ARN Interferente Pequeño/farmacología , Receptores de Adiponectina/análisis , Receptores de Adiponectina/genéticaRESUMEN
The reaction of molecular oxygen with the Si(111)-7 x 7 surface is investigated at room temperature using in situ scanning tunneling microscopy and surface stress measurements to reveal the quantitative relationship between site-specific oxygen coverage and a decrease in tensile surface stress. This relationship is described using a modified form of the reaction model originally proposed by Dujardin et al. We show that the decrease in tensile surface stress is greatest for the faulted subunits of the 7 x 7 cell and determine the stress signatures of different reaction products, including the absence of long-lived metastable species with a unique stress signature.
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BACKGROUND: Diabetes and prediabetes are chronic conditions that affect over 40% of the US adult population combined. Regular physical activity can benefit people with diabetes through improved glucose control and can reduce the conversion of prediabetes to diabetes. Studies are needed in settings where people with these conditions can be identified and provided the skills and support to increase physical activity. The primary care setting meets this need, but there are insufficient high-quality trials to recommend this approach be broadly implemented. METHODS: We conducted a randomized, 24-week pilot study in Southern California to assess the feasibility of using information technology systems available in primary care for identifying potential participants, test methods for obtaining physical activity clearance, conducting mail-based assessments, and delivering telephone-based motivational interviewing to increase physical activity. Eligibility criteria included age between 18 and 74 years, diabetes or prediabetes, and physically inactive based on a clinical assessment tool. At baseline and follow-up, physical activity was assessed by a 7-day accelerometry, cardiometabolic risk factors were collected from electronic medical records, and psychosocial factors were assessed from validated questionnaires administered through a mail survey. Participants were block randomized into intervention or usual care. Staff collecting outcome data were blinded to group assignment. Analysis of covariance was used to assess the difference at follow-up between the intervention and usual care, adjusting for baseline. RESULTS: A total of 67 participants were randomized. Follow-up mail assessments were completed by 53 participants. Of 224 potential intervention calls, 194 were completed (87%). Psychosocial measures significantly improved in four of the five factors for physical activity motivation relative to participants in the usual care arm. The more internally focused factors for exercise self-regulation and outcome expectancies scores were significantly greater for participants in intervention compared with usual care. Moderate to vigorous physical activity improved in intervention participants relative to usual care, but the difference was not statistically significant. No adverse events were noted. CONCLUSIONS: The objectives of this pilot study were met. If a fully powered trial is successful, primary care settings with "behind-the-scenes" information technology support may be appropriate to increase physical activity among patients with prediabetes and diabetes. TRIAL REGISTRATION: Exercise Promotion in Primary Care (EPPC), NCT03429088, registered on February 5, 2018.