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1.
Nature ; 620(7976): 965-970, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37648757

RESUMO

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.

2.
Phys Rev Lett ; 133(8): 082501, 2024 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-39241734

RESUMO

The neutron-rich unbound fluorine isotope ^{30}F_{21} has been observed for the first time by measuring its neutron decay at the SAMURAI spectrometer (RIBF, RIKEN) in the quasifree proton knockout reaction of ^{31}Ne nuclei at 235 MeV/nucleon. The mass and thus one-neutron-separation energy of ^{30}F has been determined to be S_{n}=-472±58(stat)±33(sys) keV from the measurement of its invariant-mass spectrum. The absence of a sharp drop in S_{n}(^{30}F) shows that the "magic" N=20 shell gap is not restored close to ^{28}O, which is in agreement with our shell-model calculations that predict a near degeneracy between the neutron d and fp orbitals, with the 1p_{3/2} and 1p_{1/2} orbitals becoming more bound than the 0f_{7/2} one. This degeneracy and reordering of orbitals has two potential consequences: ^{28}O behaves like a strongly superfluid nucleus with neutron pairs scattering across shells, and both ^{29,31}F appear to be good two-neutron halo-nucleus candidates.

4.
Nephrol Dial Transplant ; 38(3): 610-617, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-35438795

RESUMO

BACKGROUND: Early recognition of hospital-acquired acute kidney injury (AKI) may improve patient management and outcomes. METHODS: This multicentre study was conducted at three hospitals (H1-intervention; H2 and H3-controls) served by a single laboratory. The intervention bundle [an interruptive automated alerts (aAlerts) showing AKI stage and baseline creatinine in the eMR, a management guide and junior medical staff education] was implemented only at H1. Outcome variables included length-of-stay (LOS), all-cause in-hospital mortality and management quality. RESULTS: Over 6 months, 639 patients developed AKI (265 at H1 and 374 at controls), with 94.7% in general wards; 537 (84%) patients developed Stage 1, 58 (9%) Stage 2 and 43 (7%) Stage 3 AKI. Median LOS was 9 days (IQR 4-17) and was not different between intervention and controls. However, patients with AKI stage 1 had shorter LOS at H1 [median 8 versus 10 days (P = 0.021)]. Serum creatinine had risen prior to admission in most patients. Documentation of AKI was better in H1 (94.8% versus 83.4%; P = 0.001), with higher rates of nephrology consultation (25% versus 19%; P = 0.04) and cessation of nephrotoxins (25.3 versus 18.8%; P = 0.045). There was no difference in mortality between H1 versus controls (11.7% versus 13.0%; P = 0.71). CONCLUSIONS: Most hospitalized patients developed Stage 1 AKI and developed AKI in the community and remained outside the intensive care unit (ICU). The AKI eAlert bundle reduced LOS in most patients with AKI and increased AKI documentation, nephrology consultation rate and cessation of nephrotoxic medications.


Assuntos
Injúria Renal Aguda , Pacotes de Assistência ao Paciente , Humanos , Estudos de Coortes , Austrália/epidemiologia , Injúria Renal Aguda/diagnóstico , Injúria Renal Aguda/terapia , Hospitalização , Unidades de Terapia Intensiva , Creatinina , Estudos Retrospectivos
5.
Osteoporos Int ; 32(8): 1621-1629, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33559714

RESUMO

Janus kinase (JAK) inhibitors are used to treat rheumatoid arthritis (RA). We assessed the effects of tofacitinib on bone density and bone markers in association with clinical and laboratory parameters in RA. Tofacitinib stabilized bone density and resulted in a positive balance of bone turnover. INTRODUCTION: Janus kinase (JAK) inhibitors emerged as new therapeutic options in rheumatoid arthritis (RA). We have little information on how it affects areal and volumetric bone mineral density (BMD) and bone turnover markers. The aim of this study was to assess the effects of 1-year tofacitinib therapy on bone metabolism in RA. METHODS: Thirty RA patients with active disease were treated with either 5 mg bid or 10 mg bid tofacitinib for 12 months. We determined DAS28, CRP, IgM rheumatoid factor (RF), and anti-cyclic citrullinated peptide (CCP) levels, as well as serum levels of sclerostin, osteocalcin (OC), P1NP, DKK-1, OPG, RANKL, and 25-hydroxy-vitamin D3. Areal and volumetric BMD were assessed by DXA and peripheral quantitative CT (QCT), respectively. RESULTS: Twenty-six patients (13 on each arm) completed the study. Tofacitinib was clinically effective by suppressing DAS28, CRP, and HAQ. This was accompanied by the attenuation of further bone loss. Tofacitinib therapy significantly increased OC, OPG, and vitamin D3, while decreased CTX levels (p < 0.05). Age and multiple bone markers (OC, CTX, P1NP, RANKL) inversely correlated with L2-4 and femoral neck BMD by DXA. CRP, DAS28, and RANKL inversely determined volumetric BMD by QCT. Age, CRP, anti-CCP, and DKK-1 influenced the effects of tofacitinib therapy on BMD changes. CONCLUSIONS: One-year tofacitinib treatment stabilized BMD in RA patients and resulted in a positive balance of bone turnover as indicated by bone biomarkers. Further studies are needed to evaluate the potential beneficial effects of JAK inhibitors on inflammatory bone loss.


Assuntos
Artrite Reumatoide , Pirróis , Artrite Reumatoide/tratamento farmacológico , Densidade Óssea , Humanos , Piperidinas/farmacologia , Piperidinas/uso terapêutico , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Pirróis/farmacologia , Pirróis/uso terapêutico
6.
BMC Med Ethics ; 22(1): 146, 2021 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-34732195

RESUMO

BACKGROUND: Health care professionals have to judge the appropriateness of treatment in critical care on a daily basis. There is general consensus that critical care interventions should not be performed when they are inappropriate. It is not yet clear which chances of survival are considered necessary or which risk for serious disabilities is acceptable in quantitative terms for different stakeholders to start intensive care treatment. METHODS: We performed an anonymous online survey in a random sample of 1,052 participants recruited via email invitation and social media. Age, sex, nationality, education, professional involvement in health care, critical care medicine and treatment decisions in critical care medicine as well as personal experience with critical illness were assessed as potential influencing variables. Participants provided their opinion on the necessary chances of survival and the acceptable risk for serious disabilities to start a high-risk or uncomfortable therapy for themselves, relatives or for their patients on a scale of 0-100%. RESULTS: Answers ranged from 0 to 100% for all questions. A three-peak pattern with different distributions of the peaks was observed. Sex, education, being a health care professional, being involved in treatment decisions and religiosity influence these opinions. Male respondents and those with a university education would agree that a risky and uncomfortable treatment should be started even with a low chance of survival for themselves, relatives and patients. More respondents would choose a lower necessary chance of survival (0-33% survival) when deciding for patients compared to themselves or relatives to start a risky and uncomfortable treatment. On the other hand, the majority of respondents would accept only a low risk of severe disability for both themselves and their patients. CONCLUSION: No cut-off can be identified for the necessary chances of survival or the acceptable risk of disability to help quantify the "inappropriateness" of critical care treatment. Sex and education are the strongest influencing factors on this opinion. The large variation in personal opinions, depending on demographic and personality variables and education needs to be considered in the communication between health care professionals and patients or surrogates.


Assuntos
Cuidados Críticos , Estado Terminal , Atitude do Pessoal de Saúde , Comunicação , Humanos , Masculino , Inquéritos e Questionários
7.
Phys Rev Lett ; 124(15): 152502, 2020 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-32357034

RESUMO

Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230 MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6) keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60) keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of ^{28}F. Importantly, in the case of the ground state, the reconstructed ^{27}F+n momentum distribution following neutron removal from ^{29}F indicates that it arises mainly from the 1p_{3/2} neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes ^{28}F, and most probably ^{29}F, and suggests that ^{28}O is not doubly magic.

9.
Appl Opt ; 58(14): 3870-3876, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31158202

RESUMO

Infrared light is a promising candidate for the treatment of neurodegenerative diseases. Optimizing the device parameters to achieve the best optical and mechanical performance is essential for reliable in vivo operation. In this work, mechanical strength simulations and coupled optical and thermal model were used to determine optimal design parameters for maximizing overall device efficiency. Our analysis reveals that minimizing the number of integrated optical elements and optimizing the optical path leads to a 33% relative in-coupling efficiency improvement at equal mechanical robustness. Using a symmetric optrode tip with an angle of 15°, the efficiency showed a further 17% relative improvement due to the enhancement of out-coupling at the tip. To investigate the temperature rise of the brain tissue during the infrared stimulation in the case of the optimized device, a thermal simulation with pulsed infrared excitation was developed. Our results show that the optimized device provides a temperature rise of 4.42°C as opposed to 3°C for the original setup.


Assuntos
Encéfalo/fisiologia , Neurônios/fisiologia , Optogenética/instrumentação , Animais , Temperatura Corporal/fisiologia , Desenho de Equipamento , Humanos , Raios Infravermelhos , Modelos Teóricos , Dispositivos Ópticos , Estimulação Transcraniana por Corrente Contínua
10.
Cell Mol Neurobiol ; 38(5): 1081-1097, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29464444

RESUMO

Cuprizone (CZ) is a widely used copper chelating agent to develop non-autoimmune animal model of multiple sclerosis, characterized by demyelination of the corpus callosum (CC) and other brain regions. The exact mechanisms of CZ action are still arguable, but it seems that the only affected cells are the mature oligodendrocytes, possibly via metabolic disturbances caused by copper deficiency. During the pathogenesis of multiple sclerosis, high amount of deposited iron can be found throughout the demyelinated areas of the brain in the form of extracellular iron deposits and intracellularly accumulated iron in microglia. In the present study, we used the accepted experimental model of 0.2% CZ-containing diet with standard iron concentration to induce demyelination in the brain of C57BL/6 mice. Our aim was to examine the changes of iron homeostasis in the CC and as a part of the systemic iron regulation, in the liver. Our data showed that CZ treatment changed the iron metabolism of both tissues; however, it had more impact on the liver. Besides the alterations in the expressions of iron storage and import proteins, we detected reduced serum iron concentration and iron stores in the liver, together with elevated hepcidin levels and feasible disturbances in the Fe-S cluster biosynthesis. Our results revealed that the CZ-containing diet influences the systemic iron metabolism in mice, particularly the iron homeostasis of the liver. This inadequate systemic iron regulation may affect the iron homeostasis of the brain, eventually indicating a relationship among CZ treatment, iron metabolism, and neurodegeneration.


Assuntos
Cuprizona/administração & dosagem , Ferro/metabolismo , Esclerose Múltipla/metabolismo , Animais , Axônios/patologia , Axônios/ultraestrutura , Proteínas de Transporte de Cátions/metabolismo , Corpo Caloso/metabolismo , Citosol/metabolismo , Modelos Animais de Doenças , Regulação da Expressão Gênica , Hepcidinas/sangue , Hepcidinas/genética , Hepcidinas/metabolismo , Metabolismo dos Lipídeos/genética , Fígado/metabolismo , Imageamento por Ressonância Magnética , Masculino , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Esclerose Múltipla/genética , Esclerose Múltipla/patologia , Proteína Básica da Mielina/metabolismo , Bainha de Mielina/metabolismo , Bainha de Mielina/patologia , Neuroglia/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
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