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1.
Nature ; 607(7918): 260-265, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35831598

RESUMO

In spite of the high-density and strongly correlated nature of the atomic nucleus, experimental and theoretical evidence suggests that around particular 'magic' numbers of nucleons, nuclear properties are governed by a single unpaired nucleon1,2. A microscopic understanding of the extent of this behaviour and its evolution in neutron-rich nuclei remains an open question in nuclear physics3-5. The indium isotopes are considered a textbook example of this phenomenon6, in which the constancy of their electromagnetic properties indicated that a single unpaired proton hole can provide the identity of a complex many-nucleon system6,7. Here we present precision laser spectroscopy measurements performed to investigate the validity of this simple single-particle picture. Observation of an abrupt change in the dipole moment at N = 82 indicates that, whereas the single-particle picture indeed dominates at neutron magic number N = 82 (refs. 2,8), it does not for previously studied isotopes. To investigate the microscopic origin of these observations, our work provides a combined effort with developments in two complementary nuclear many-body methods: ab initio valence-space in-medium similarity renormalization group and density functional theory (DFT). We find that the inclusion of time-symmetry-breaking mean fields is essential for a correct description of nuclear magnetic properties, which were previously poorly constrained. These experimental and theoretical findings are key to understanding how seemingly simple single-particle phenomena naturally emerge from complex interactions among protons and neutrons.

2.
Nature ; 581(7809): 396-400, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32461650

RESUMO

Molecular spectroscopy offers opportunities for the exploration of the fundamental laws of nature and the search for new particle physics beyond the standard model1-4. Radioactive molecules-in which one or more of the atoms possesses a radioactive nucleus-can contain heavy and deformed nuclei, offering high sensitivity for investigating parity- and time-reversal-violation effects5,6. Radium monofluoride, RaF, is of particular interest because it is predicted to have an electronic structure appropriate for laser cooling6, thus paving the way for its use in high-precision spectroscopic studies. Furthermore, the effects of symmetry-violating nuclear moments are strongly enhanced5,7-9 in molecules containing octupole-deformed radium isotopes10,11. However, the study of RaF has been impeded by the lack of stable isotopes of radium. Here we present an experimental approach to studying short-lived radioactive molecules, which allows us to measure molecules with lifetimes of just tens of milliseconds. Energetically low-lying electronic states were measured for different isotopically pure RaF molecules using collinear resonance ionisation at the ISOLDE ion-beam facility at CERN. Our results provide evidence of the existence of a suitable laser-cooling scheme for these molecules and represent a key step towards high-precision studies in these systems. Our findings will enable further studies of short-lived radioactive molecules for fundamental physics research.

3.
Zhonghua Yu Fang Yi Xue Za Zhi ; 58(1): 81-86, 2024 Jan 06.
Artigo em Chinês | MEDLINE | ID: mdl-38228553

RESUMO

To explore screening tools for children with autism spectrum disorder (ASD), which are convenient for primary hospitals, it can provide basic data for formulating ASD prevention policies. This was a cross-sectional study by cluster sampling. Huyi District and Xincheng District were extracted for investigation in Xi'an City. From July 2021 to September 2022, all children aged from 3 months to 36 months who live in the two districts were subjected to primary screening. The child care physician used the routine screening tool "warning signs checklist for screening psychological, behavioral and developmental problems of children" and cartoon pictures of "early high-risk warning signs of autism", the children who were positive in the initial screening were referred to the district level maternal and child health hospital for re-screening, and those who were positive in the re-screening were referred to Xi 'an Children's Hospital for diagnosis. The results showed that a total of 17 905 children aged from 3 months to 36 months were initially screened in the two districts, including 10 588 children aged from 18 months to 36 months, 50 children who were positive in the initial screening and 50 children who were re-screened. 23 children (18 boys and 5 girls) were diagnosed with ASD. The prevalence rate of ASD in children was 2.17‰ (95% confidence interval:1.29‰-3.06‰). 42 children were positive for "warning signs checklist" at the preliminary screening, and 19 were confirmed as ASD. 27 children were positive for "cartoon pictures" in the preliminary screening, and 23 were confirmed with ASD. The "cartoon pictures" in the preliminary screening and diagnosis of consistent rate was higher than the "warning signs checklist", two kinds of screening methods comparison were statistically significant difference in the odds of consistent (χ2=11.01, P=0.001). In conclusion, relying on the three-level network of maternal and child health care, it is conducive to the whole process management of screening and diagnosis of children with ASD, and to guide the formulation of prevention policies. The cartoon pictures of "early high-risk warning signs of autism" can assist the identification of children with ASD based on the "warning signs checklist", which is simple, effective and suitable for promotion in the community health care.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Masculino , Feminino , Humanos , Transtorno do Espectro Autista/diagnóstico , Transtorno do Espectro Autista/epidemiologia , Estudos Transversais , Programas de Rastreamento/métodos , Prevalência
4.
Phys Rev Lett ; 131(24): 242501, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38181133

RESUMO

We report here the first observation of the 0_{2}^{+} state of ^{8}He, which has been predicted to feature the condensatelike α+^{2}n+^{2}n cluster structure. We show that this state is characterized by a spin parity of 0^{+}, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new insights into clustering in neutron-rich nuclear systems and the pair correlation and condensation in quantum many-body systems under strong interactions.

5.
Zhonghua Zhong Liu Za Zhi ; 45(7): 605-612, 2023 Jul 23.
Artigo em Chinês | MEDLINE | ID: mdl-37462017

RESUMO

Objective: To evaluate the efficacy and influencing factors of programmed death protein 1 (PD-1) monoclonal antibody rechallenge therapy in advanced gastric cancer (GC). Methods: The clinical data of patients with advanced GC who were treated with anti-PD-1 rechallenge in Henan Cancer Hospital from January 2020 to December 2021 were collected retrospectively. The progression-free survival (PFS) was defined as the time from the first or second used of anti-PD-1 treatment to the date of disease progression or the last follow-up, named PFS(1) and PFS(2), respectively. Kaplan-Meier method and Log rank test were used for survival analysis, Cox proportional hazard model was used to analyze the influencing factors. Results: A total of 60 patients with anti-PD-1 rechallenge therapy were collected, the median follow-up time was 12.2 months. The median progression-free survival (PFS(2)) of anti-PD-1 rechallenge therapy was 2.9 months, the objective response rate (ORR) was 16.7%, and the disease control rate (DCR) was 55.0%. The median PFS(2) of the first and second anti-PD-1 identical and different rechallenge treatment was 3.5 months and 1.9 months (P=0.007) respectively. The median PFS(2) of positive PD-L1 expression in rechallenge therapy was 3.4 months, ORR was 22.7%, and DCR was 63.6%; the median PFS(2) was 4.5 months, ORR was 27.3%, and DCR was 54.5% in patients with median PFS(1)≥6 months. Multivariate analysis showed that peritoneal metastasis was independently associated with anti-PD-1 rechallenge therapy with PFS(2) (HR=2.327, 95% CI, 1.066-5.082, P=0.034). The incidence of adverse reactions in grade 1-2 and grade 3-4 of anti-PD-1 rechallenge therapy was 83.3%, and 35.0%, respectively, and the safety was controllable. Conclusion: Rechallenge therapy with anti-PD-1 is a feasible treatment in advanced GC, but the screening of suitable population for rechallenge therapy still needs prospective data analysis and verification.


Assuntos
Neoplasias Gástricas , Humanos , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/patologia , Estudos Retrospectivos , Estudos Prospectivos , Anticorpos Monoclonais/uso terapêutico , Imunoterapia/efeitos adversos
6.
Zhonghua Yi Xue Za Zhi ; 103(48): 3917-3923, 2023 Dec 26.
Artigo em Chinês | MEDLINE | ID: mdl-38129168

RESUMO

Objective: To explore the safety and myocardial protection efficacy of del Nido cardioplegia in adult cardiac and major vascular surgery with long aortic cross-clamp (ACC) time. Methods: A total of 2 536 patients who underwent adult cardiac and major vascular surgery with ACC time>90 min at Beijing Anzhen Hospital from March 2018 to March 2023 were collected. The patients were divided into two groups according to the type of cardioplegia solution: the del Nido cardioplegia solution group (DC group) and the cold blood cardioplegia solution group (BC group). Preoperative baseline data of the patients (age, gender, comorbidities, ejection fraction, etc) were adjusted using propensity score matching (PSM). Cardiopulmonary bypass (CPB) time, ACC time, total amount of cardioplegia solution, in-hospital mortality rate, length of intensive care unit (ICU) stay, mechanical ventilation time, postoperative complications, left ventricular ejection fraction, and troponin levels were compared between the two groups. Results: After PSM, a total of 306 patients were included, including 223 males and 83 females, with a mean age of (52.0±12.3) years. There were 153 cases in the DC group and 153 cases in the BC group. Compared with the DC group, the cross-clamp time was longer [109(100, 150) min vs 102(91, 133) min, P<0.001], the rate of return to spontaneous rhythm was lower [51.6% (79/153) vs 86.9%(133/153), P<0.001], and intraoperative peak glucose was higher [12.6 (6.5, 15.9) mmol/L vs 10.1 (8.5, 12.4) mmol/L, P=0.005] in the BC group. In addition, perioperative mortality [4.6% (7/153) vs 3.3% (5/153), P=0.132], stroke[3.9% (6/153) vs 3.3% (5/153), P=0.759], renal insufficiency [3.3% (5/153) vs 6.5% (10/153), P=0.186], atrial fibrillation [4.6% (7/153) vs 2.6% (4/153), P=0.652] and low cardiac output syndrome [3.9% (6/153) vs 4.6% (7/153), P=0.716] did not differ between the two groups. Compared with BC group, DC group had lower level of high sensitivity troponin (hsTnI) [1.2 (0.8, 1.8) µg/L vs 1.3 (0.9, 2.3) µg/L, P=0.030] and creatine kinase isoenzyme (CK-MB) [31.0 (20.0, 48.9) µg/L vs 37.0 (24.0, 58.9) µg/L, P=0.011] at 24 h postoperatively, and shorter length of ICU stay [35.6 (19.8, 60.5) h vs 42.6 (21.9, 83.6) h, P=0.015] and mechanical ventilation time [20.5 (15.5, 41.0) h vs 31.5 (17.1, 56.0) h, P=0.012]. Subgroup analysis showed that in the 120-180 minute subgroup, patients in the DC group had a shorter cross-clamp time [132 (124, 135) min vs 136 (124, 138) min, P<0.001], while levels of hsTnI [1.6 (1.1, 2.0) µg/L vs 1.4 (1.0, 2.6) µg/L, P=0.030] and CK-MB [38.8 (23.5, 55.5) µg/L vs 37.0 (24.5, 62.3) µg/L, P=0.011] were higher than those in the BC group. Conclusions: In adult cardiac and major vascular surgery with ACC times>90 min, comparable myocardial protection is observed with the use of DC compared with BC. Additional advantages in glycemic control, return to spontaneous rhythm, and improved surgical procedures make DN an attractive alternative for myocardial protection in adult cardiac surgery.


Assuntos
Parada Cardíaca Induzida , Função Ventricular Esquerda , Masculino , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Volume Sistólico , Parada Cardíaca Induzida/métodos , Soluções Cardioplégicas , Troponina , Procedimentos Cirúrgicos Vasculares , Estudos Retrospectivos
7.
Phys Rev Lett ; 128(2): 022502, 2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-35089728

RESUMO

Collinear laser spectroscopy is performed on the nickel isotopes ^{58-68,70}Ni, using a time-resolved photon counting system. From the measured isotope shifts, nuclear charge radii R_{c} are extracted and compared to theoretical results. Three ab initio approaches all employ, among others, the chiral interaction NNLO_{sat}, which allows an assessment of their accuracy. We find agreement with experiment in differential radii δ⟨r_{c}^{2}⟩ for all employed ab initio methods and interactions, while the absolute radii are consistent with data only for NNLO_{sat}. Within nuclear density functional theory, the Skyrme functional SV-min matches experiment more closely than the Fayans functional Fy(Δr,HFB).

8.
Phys Rev Lett ; 127(3): 033001, 2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34328758

RESUMO

Isotope shifts of ^{223-226,228}Ra^{19}F were measured for different vibrational levels in the electronic transition A^{2}Π_{1/2}←X^{2}Σ^{+}. The observed isotope shifts demonstrate the particularly high sensitivity of radium monofluoride to nuclear size effects, offering a stringent test of models describing the electronic density within the radium nucleus. Ab initio quantum chemical calculations are in excellent agreement with experimental observations. These results highlight some of the unique opportunities that short-lived molecules could offer in nuclear structure and in fundamental symmetry studies.

9.
Zhonghua Yu Fang Yi Xue Za Zhi ; 55(9): 1123-1128, 2021 Sep 06.
Artigo em Chinês | MEDLINE | ID: mdl-34619931

RESUMO

Objective: To investigate the role of autophagy mediated by mTOR signaling pathway in the inhibition of osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) induced by cadmium. Methods: HBMSCs were divided into 0, 2.5 or 5.0 µmol/L groups according to the exposure dose of cadmium chloride (CdCl2), and each group was treated for 1 day, 4 days and (or) 7 days. The ALP activity and mRNA and protein expression levels of osteogenesis markers (ALP, RUNX2 and OSTERIX), autophagy-related proteins (LC3 and Beclin-1) and mTOR signaling pathway related proteins (mTOR, p-mTOR and p-p70S6K) expression, alkaline phosphatase staining and alizarin red staining were detected. MHY 1485 was selected as the signaling pathway activator. The control group, CdCl2 group (5.0 µmol/L), MHY 1485 group and CdCl2+MHY 1485 combined treatment group were set. After 7 days of treatment, the expression levels of autophagy related proteins and mTOR signaling pathway related proteins of hBMSCs in each group were detected. Results: There was no significant difference in ALP activity between 0, 2.5 and 5.0 µmol/L groups on day 1 and 4 (P>0.05); On day 7, compared with the 0 µmol/L group, the ALP activity, expression of osteogenic markers (ALP, RUNX2, OSTERIX) and mTOR signaling pathway related proteins (mTOR, p-mTOR, p-p70S6K) expression decreased in the 2.5 and 5.0 µmol/L group (P<0.05). Compared with the 0 µmol/L group, the staining of the 2.5 and 5.0 µmol/L groups became lighter, and the formation of ALP and mineralized nodules was reduced. Compared with the CdCl2 group, the autophagy related protein expression in the CdCl2+MHY 1485 combined treatment group decreased, and the mTOR signaling pathway related protein expression increased. The difference was statistically significant (P<0.05). Conclusion: The inhibition of osteogenic differentiation of hBMSCs by cadmium may be related to autophagy mediated by mTOR signaling pathway.


Assuntos
Células-Tronco Mesenquimais , Osteogênese , Autofagia , Cádmio , Diferenciação Celular , Humanos , Células-Tronco Mesenquimais/metabolismo , Osteoblastos/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo
10.
Artigo em Chinês | MEDLINE | ID: mdl-34218572

RESUMO

Objective: To explore the relationship between shift work and menopausal age and menstruation span of retired women. Methods: During July 2017 and October 2018, the research was performed by using cluster sampling in nine districts of Shenzhen City to select all permanent residents (3518 people) with Shenzhen household registration in which was equal to or over 60 years old from the Community Health Service Centers. The data of age, marital status, menopausal age, smoking, drinking, shift experience and shift years were collected. The relationship between shift work and menopausal age as well as menstruation span of professional women were analyzed by multivariate linear regression model. Results: There were 359 people (10.2%) in the shift experience group, the menopausal age was (49.71±3.63) years, and the menstrual period was (34.27±3.92) years. The non-shift experience group were 3159 people (89.8%) , the menopausal age was (50.20±3.60) years, and the menstrual period was (34.86±4.13) years. The differences of menopausal age and menstrual years between the two groups were statistically significant (P<0.05) . After adjusting for factors such as passive smoking and drinking, the results of the multiple linear regression model showed that menopausal age, menstrual years were negatively correlated with shift work (ß=-0.493, -0.575, P<0.05) . Conclusion: Shifts are related to women's menopausal age and menstrual years, and attention should be paid to the impact of work intensity and circadian rhythm on the occupational health of female employees.


Assuntos
Menstruação , Jornada de Trabalho em Turnos , Consumo de Bebidas Alcoólicas , Feminino , Humanos , Menopausa , Pessoa de Meia-Idade , Fumar
11.
Phys Rev Lett ; 124(13): 132502, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32302185

RESUMO

We present the first laser spectroscopic measurement of the neutron-rich nucleus ^{68}Ni at the N=40 subshell closure and extract its nuclear charge radius. Since this is the only short-lived isotope for which the dipole polarizability α_{D} has been measured, the combination of these observables provides a benchmark for nuclear structure theory. We compare them to novel coupled-cluster calculations based on different chiral two- and three-nucleon interactions, for which a strong correlation between the charge radius and dipole polarizability is observed, similar to the stable nucleus ^{48}Ca. Three-particle-three-hole correlations in coupled-cluster theory substantially improve the description of the experimental data, which allows to constrain the neutron radius and neutron skin of ^{68}Ni.

12.
Phys Rev Lett ; 124(11): 112501, 2020 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-32242689

RESUMO

The gyromagnetic factor of the low-lying E=251.96(9) keV isomeric state of the nucleus ^{99}Zr was measured using the time-dependent perturbed angular distribution technique. This level is assigned a spin and parity of J^{π}=7/2^{+}, with a half-life of T_{1/2}=336(5) ns. The isomer was produced and spin aligned via the abrasion-fission of a ^{238}U primary beam at RIKEN RIBF. A magnetic moment |µ|=2.31(14)µ_{N} was deduced showing that this isomer is not single particle in nature. A comparison of the experimental values with interacting boson-fermion model IBFM-1 results shows that this state is strongly mixed with a main νd_{5/2} composition. Furthermore, it was found that monopole single-particle evolution changes significantly with the appearance of collective modes, likely due to type-II shell evolution.

13.
Phys Rev Lett ; 124(19): 192501, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32469564

RESUMO

An inelastic excitation and cluster-decay experiment ^{2}H(^{16}C,^{4}He+^{12}Be or ^{6}He+^{10}Be)^{2}H was carried out to investigate the linear-chain clustering structure in neutron-rich ^{16}C. For the first time, decay paths from the ^{16}C resonances to various states of the final nuclei were determined, thanks to the well-resolved Q-value spectra obtained from the threefold coincident measurement. The close-threshold resonance at 16.5 MeV is assigned as the J^{π}=0^{+} band head of the predicted positive-parity linear-chain molecular band with (3/2_{π}^{-})^{2}(1/2_{σ}^{-})^{2} configuration, according to the associated angular correlation and decay analysis. Other members of this band were found at 17.3, 19.4, and 21.6 MeV based on their selective decay properties, being consistent with the theoretical predictions. Another intriguing high-lying state was observed at 27.2 MeV which decays almost exclusively to ^{6}He+^{10}Be(∼6 MeV) final channel, corresponding well to another predicted linear-chain structure with the pure σ-bond configuration.

14.
J Biol Regul Homeost Agents ; 34(3): 785-794, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32723437

RESUMO

Previous reports indicated that specific cyclooxygenase-2 (COX-2) inhibitor suppresses osteoarthritis (OA). This study aimed to further explore the possible mechanism of Rofecoxib as a COX-2 inhibitor on the inhibition of chondrocyte (CH) hypertrophic development and tested the optimal treatment of Rofecoxib on CH. Basically, IL-1ß was used as a stimulus to establish a degenerated CH model. Immunofluorescence, Western blot, and RT-PCR were performed to determine the gene expression of Axin2, ß-catenin, GSK3ß, collagen X, collagen II, COX-2, PGE-2, SOX-9, Runx-2, and MMP- 13 expression. Cell Counting Kit (CCK-8) assay was used to analyze the viability of CHs. The data indicated that Rofecoxib significantly inhibited COX-2 expression and had less harmful effects on CH viability. Rofecoxib reversed the IL-1ß-induced upregulation of collagen X, COX-2, PGE-2, Runx-2, and MMP-13 expression, and promoted the viability of collagen II, SOX-9 expression of CHs. Furthermore, Rofecoxib suppressed Axin2, ß-catenin, and GSK3ß expression of the Wnt pathway, which was activated by IL-1ß or human recombinant Wnt-1 protein treatment. Therefore, Rofecoxib is an effective COX-2 inhibitor that protects CHs from hypertrophy by suppression of the Wnt/ß-catenin pathway.


Assuntos
Condrócitos/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase 2/farmacologia , Lactonas/farmacologia , Sulfonas/farmacologia , Via de Sinalização Wnt , Células Cultivadas , Condrócitos/citologia , Humanos , Hipertrofia , beta Catenina
15.
Phys Rev Lett ; 122(19): 192502, 2019 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-31144969

RESUMO

The change in mean-square nuclear charge radii δ⟨r^{2}⟩ along the even-A tin isotopic chain ^{108-134}Sn has been investigated by means of collinear laser spectroscopy at ISOLDE/CERN using the atomic transitions 5p^{2} ^{1}S_{0}→5p6 s^{1}P_{1} and 5p^{2} ^{3}P_{0}→5p6s ^{3}P_{1}. With the determination of the charge radius of ^{134}Sn and corrected values for some of the neutron-rich isotopes, the evolution of the charge radii across the N=82 shell closure is established. A clear kink at the doubly magic ^{132}Sn is revealed, similar to what has been observed at N=82 in other isotopic chains with larger proton numbers, and at the N=126 shell closure in doubly magic ^{208}Pb. While most standard nuclear density functional calculations struggle with a consistent explanation of these discontinuities, we demonstrate that a recently developed Fayans energy density functional provides a coherent description of the kinks at both doubly magic nuclei, ^{132}Sn and ^{208}Pb, without sacrificing the overall performance. A multiple correlation analysis leads to the conclusion that both kinks are related to pairing and surface effects.

16.
Zhonghua Yu Fang Yi Xue Za Zhi ; 53(3): 309-315, 2019 Mar 06.
Artigo em Chinês | MEDLINE | ID: mdl-30841673

RESUMO

Objective: To study the alterations of mitochondrial biological characteristics during both cellular replicative and premature senescence induced by hydrogen peroxide in human embryonic lung fibroblasts (HEFs). Methods: The premature senescence was induced by 400 µmol/L H(2)O(2) once a day at the same time and with 2 hours each time, after four consecutive days the premature senescence models were classified into premature senescence initiation group (PSi) and premature senescence persistence group (PSp). Based on the life span of HEFs, the cell replicative senescence was divided into five groups included young-age (22 PDL), middle-age (35 PDL), replicative senescence (49 PDL), PSi and PSp. The mitochondrial distribution, relative content, adenosine triphosphate (ATP) contents, 8-hydroxydeoxyguanosine (8-OHdG) levels, the relative mitochondrial transcription factor A (TFAM) as well as mitochondrial DNA methyltransferase 1 (mtDNMT1) mRNA levels, mtDNA copy number, the relative TFAM protein level and the total enzyme activity of mitochondrial DNA methyltransferases (mtDNMTs) were detected in five senescence groups. Results: The mtDNA copy number, 8-OHdG contents, level of mtDNMT1 mRNA and mtDNMTs activity in 49 PDL group were higher than those in 22 PDL group (all P values <0.05); The level of 8-OHdG in PSi was higher than that in 22 PDL group (P<0.05); The ATP contents, mtDNA copy number, the mRNA and protein expression levels of TFAM and mtDNMTs activity of PSp were higher than those in 22 PDL group (all P values<0.05). Conclusion: During the cellular senescence of HEFs, the higher mtDNA copy number and mtDNMTs activity were common features regardless of replicative or premature senescence, with possibility that oxidative stress was involved in modifying the occurrence of premature senescence.


Assuntos
Senescência Celular/efeitos dos fármacos , Fibroblastos/citologia , Peróxido de Hidrogênio/farmacologia , Pulmão/citologia , Mitocôndrias/metabolismo , Humanos , Pulmão/embriologia
17.
Nanotechnology ; 29(12): 125201, 2018 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-29355833

RESUMO

Zigzag silicene nanoribbons (ZSiNRs) in the ferromagnetic edge ordering have a metallic behavior, which limits their applications in spintronics. Here a robustly half-metallic property is achieved by the boron substitution doping at the edge of ZSiNRs. When the impurity atom is replaced by the aluminum atom, the doped ZSiNRs possess a spin semiconducting property. Its band gap is suppressed with the increase of ribbon's width, and a pure thermal spin current is achieved by modulating ribbon's width. Moreover, a negative differential thermoelectric resistance in the thermal charge current appears as the temperature gradient increases, which originates from the fact that the spin-up and spin-down thermal charge currents have diverse increasing rates at different temperature gradient regions. Our results put forward a promising route to design multi-functional spintronic devices which may be applied in future low-power-consumption technologies.

18.
Zhonghua Yu Fang Yi Xue Za Zhi ; 52(10): 994-1002, 2018 Oct 06.
Artigo em Chinês | MEDLINE | ID: mdl-30392316

RESUMO

Objective: A new ion exchange column technology was used to establish an efficient and sensitive method for the detection of inorganic arsenic. Methods: Based on the new As Specia Fast Column, the pretreatment methods, liquid phase separation and mass spectrometry determination conditions of inorganic arsenic in rice were optimized. Finally, arsenic compounds were separated by As Specia Fast Column and detected by liquid chromatography inductively coupled plasma mass spectrometry. The external standard method was used for quantitative analysis. The detection limit, precision and accuracy of the method were determined by measuring the content of arsenic compounds in rice samples and rice standard samples. At the same time, three Guangdong rice samples were selected as the experimental samples of this study, and 1 g of each sample was weighed and measured in parallel three times. The method was compared with the method of liquid chromatography-atomic fluorescence spectrometry (LC-AFS) and liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) in the national standard. Results: The inorganic arsenic in rice was extracted with 0.5% nitric acid solution at 65 ℃ for 15 h, and the pH was adjusted to alkaline. The mobile phase A (8 mmol/L HNO(3), 50 mmol/L NH(3)·H(2)O) and mobile phase B (40 mmol/L HNO(3), 80 mmol/L NH(3)·H(2)O) were used as the mobile phase gradient elution (93%) . Five arsenic compounds can reach baseline separation under the conditions of RF power of 1 500 W and atomization gas flow of 0.97 L/min. The detection limits ranged from 0.114 to 0.331 µg/L, and the inorganic arsenic content in rice samples ranged from 0.063 to 0.232 mg/kg. The results of determination of arsenic compounds in rice flour reference materials were all within the uncertainty range indicated by the standard. The recoveries were 86.7%~106.7%, and the precision was 1.9%-12.5%. Compared with national standards, the results of determination of arsenate in rice were relatively close (using this method, LC-AFS, LC-ICP-MS to detect the content of arsenate in rice samples 1 was 0.231, 0.226, 0.236 mg/kg, respectively). However, due to insufficient sensitivity, the national standard method is difficult to detect low levels of arsenic compounds (Arsenobetaine was not detected in rice sample 1). The method can detect the content of arsenobetaine in rice sample 1 was 0.023 mg/kg. Conclusion: The established method can meet the requirements of inorganic arsenic determination in rice, and it is more rapid and accurate than the current national standard. It can better monitor and evaluate the content of i-As in rice, and provide accurate data for comprehensively grasping and evaluating the safety of rice consumption of residents.


Assuntos
Arsênio/análise , Análise de Alimentos/métodos , Oryza/química , China , Cromatografia Líquida , Humanos , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem
19.
Zhonghua Yan Ke Za Zhi ; 54(8): 611-616, 2018 Aug 11.
Artigo em Chinês | MEDLINE | ID: mdl-30107655

RESUMO

Objective: Quality of life and the influencing factors in patients with diabetic retinopathy before and after receiving treatment of pan-retinal photocoagulation (PRP) were studied. Methods: Prospective study. A total of 55 diabetic retinopathy patients were collected at Beijing Friendship Hospital, Capital Medical University from November 2016 to August 2017 and were surveyed using Vision Function Questionaire (VFQ-25) to evaluate their quality of life before and 3 months after treatment with PRP. According to diagnostic criteria, the patients were divided into two groups: severe nonproliferative diabetic retinopathy(NPDR) and proliferative diabetic retinopathy group(PDR). SPSS was used for statistical analysis. Results: The score of VFO-25 general health before PRP treatment was 62.73±14.20, obviously lower the other sub scale scores of VFO-25. The results of variance analysis there was significant statistical difference between the composite score and the different educational levels (F=2.94, P<0.05), but there was no statistical difference for diabetes duration (F=3.01, P<0.05). The composite score was significantly significance between the severe NPDR and PDR group(t=8.95, P<0.05). The patients with hyperlipidemia (t=-3.21, P<0.05), hypertension(t=-2.32, P<0.05) and renal insufficiency(t=-2.05, P=0.045) has lower composite score. There was high relationship for age among the factors of worse logMAR vision, better logMAR vision and age (r=-0.47, P<0.05; r=-0.38, P<0.05; r=-0.26, P<0.05). The scores of VFQ-25 subscale of social function (t=-2.07, P<0.05) , role limitations (t=-2.38, P<0.05) , dependency (t=-2.99, P<0.05) and mental health (t=-2.26, P<0.05) was significantly increased after treatment of PRP. The score of ocular pain was obviously decreased (t=4.19, P<0.001) ; there were no significance in other sub scale scores. Conclusions: This study showed that the degree of visual acuity, the severity of DR and age were an important factor affecting the quality of life in DR patients. PRP therapy could improve the mental health and social field of DR patients, but failed to improve the scores of other visual functions in the patients. (Chin J Ophthalmol, 2018, 54:611-616).


Assuntos
Retinopatia Diabética , Fotocoagulação a Laser , Qualidade de Vida , Retinopatia Diabética/complicações , Retinopatia Diabética/terapia , Humanos , Estudos Prospectivos , Acuidade Visual
20.
Osteoporos Int ; 28(8): 2335-2341, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28382553

RESUMO

The present study shows that hip fracture women had higher serum periostin (sPostn) levels. The elevation of sPostn is associated with bone density loss, yet fracture itself may even increase sPostn levels during early healing phase. INTRODUCTION: The study aims to quantify the associations of sPostn levels with bone density loss and the possible effect on the fracture healing. METHODS: This study enrolled 261 older women with osteoporotic hip fracture and 106 age-matched women without fracture serving as controls. Clinical features, bone mineral density (BMD), and bone turnover markers including sPostn level were measured after fracture within 2 days. Follow-up sPostn levels during 1 year after 2 days were available for 128 patients. RESULTS: Initial levels of sPostn after fracture were significantly higher in patients than controls. sPostn was correlated with BMD of femoral neck (r = -0.529, P < 0.001), ß-isomerized C-terminal crosslinking of type I collagen (ß-CTX) (r = 0.403, P = 0.008), and N-terminal procollagen of type I collagen (PINP) (r = 0.236, P = 0.042) in the entire cohort. After multivariate analysis, sPostn remained as an independent risk factor for femoral neck BMD, which explained 19.1% of the variance in BMD. sPostn sampled within 7 days after fracture were acutely increasing from day 2 and then decreased and maintained at slightly high levels at 360 days. The percentage changes of sPostn positively correlated with the variation in ß-CTX (r = 0.396, P = 0.002) and PINP (r = 0.180, P = 0.033) at day 7 after fracture. CONCLUSIONS: High sPostn levels were an independent predictor of femoral neck BMD in older women presenting with an acute hip fracture. Increased sPostn levels during early healing phase may imply that Postn play a role in bone repair.


Assuntos
Densidade Óssea/fisiologia , Moléculas de Adesão Celular/sangue , Fraturas do Quadril/sangue , Osteoporose Pós-Menopausa/sangue , Fraturas por Osteoporose/sangue , Absorciometria de Fóton/métodos , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Estudos de Casos e Controles , Moléculas de Adesão Celular/fisiologia , Feminino , Colo do Fêmur/fisiopatologia , Consolidação da Fratura/fisiologia , Fraturas do Quadril/fisiopatologia , Humanos , Vértebras Lombares/fisiopatologia , Osteoporose Pós-Menopausa/fisiopatologia , Fraturas por Osteoporose/fisiopatologia
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