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1.
Phys Rev Lett ; 124(2): 027203, 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-32004033

RESUMO

Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI), which gives rise to topological spin textures, such as skyrmions. However, the DMI has not yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping for spin waves. In this work, we experimentally evidence the interfacial DMI in a 7-nm-thick YIG film by measuring the nonreciprocal spin-wave propagation in terms of frequency, amplitude, and most importantly group velocities using all electrical spin-wave spectroscopy. The velocities of propagating spin waves show chirality among three vectors, i.e., the film normal direction, applied field, and spin-wave wave vector. By measuring the asymmetric group velocities, we extract a DMI constant of 16 µJ/m^{2}, which we independently confirm by Brillouin light scattering. Thickness-dependent measurements reveal that the DMI originates from the oxide interface between the YIG and garnet substrate. The interfacial DMI discovered in the ultrathin YIG films is of key importance for functional chiral magnonics as ultralow spin-wave damping can be achieved.

2.
Skeletal Radiol ; 49(2): 273-280, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31352490

RESUMO

OBJECTIVE: Osteoporosis is diagnosed based on the results of BMD assessment and/or fragility fractures. Vertebral fracture is the most common fragility fracture. Many vertebral fractures are asymptomatic and are not clinically recognized. Early detection of vertebral fracture may increase diagnosis of osteoporosis. In this study, we performed BMD measurement combined with vertebral fracture assessment (VFA) by DXA for the postmenopausal women receiving the first bone densitometry and studied the impact of VFA on the diagnosis of osteoporosis. METHODS: A total of 502 postmenopausal women were enrolled in our study. Patients' age was 66.7 ± 9.5 years. All patients had BMD assessment and VFA by dual-energy X-ray absorptiometry. Genant's semiquantitative assessment was used. The impact of VFA on the diagnosis of osteoporosis was studied. All parameters of groups were compared using the Chi-squared test. RESULTS: There were 257 patients with T-score ≤-2.5, 202 patients with a T-score between -1 and - 2.5, and 43 patients with BMD within the normal range. There were 162 patients with 345 fractured vertebrae identified by VFA, among which 84% of patients were previously unknown. Osteoporosis or severe osteoporosis was presented in 51.2% patients diagnosed by BMD alone, in 55.2% patients diagnosed by BMD plus fracture history, and in 62.4% of patients diagnosed by BMD plus fracture history and VFA. Severe osteoporosis significantly increased by 17.2% in patients receiving VFA. CONCLUSIONS: VFA combined with BMD can detect previously unknown vertebral fractures and increase clinical diagnosis of osteoporosis. It is plausible to speculate that this method should be considered in postmenopausal women for the first BMD assessment.

3.
Exp Ther Med ; 18(5): 3715-3722, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31616505

RESUMO

Bacterial resistance to antimicrobial agents, including multidrug resistance, is an increasing problem in the treatment of infectious diseases. The development of resistance-modifying agents represents a potential strategy to alleviate the spread of bacterial resistance to antibiotics. A checkerboard microdilution assay was used to determine the synergy of jatrorrhizine and the antibiotic, norfloxacin (NFX). A bacterial ethidium bromide efflux assay, reverse transcription semi-quantitative polymerase chain reaction analysis and molecular docking study were performed. The three-dimensional structure of NorA multidrug efflux pump (NorA) was generated using a multiple threading approach. A murine thigh infection model was used to evaluate the in vivo synergistic effect. As a natural product, jatrorrhizine exhibited little antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) SA1199B with a minimum inhibitory concentration (MIC) of 64 mg/l. According to the investigations of the mechanism, jatrorrhizine significantly inhibited bacterial drug efflux and the expression of NorA in the mRNA level as it can bind to NorA by hydrogen-bonds, hydrophobic and electrostatic interactions. The in vivo synergistical bactericidal activity of jatrorrhizine and NFX against MRSA was confirmed in a murine thigh infection model. As a novel resistance-modifying agent, jatrorrhizine exhibited in vitro and in vivo synergistic activities against MRSA, and inhibited bacterial drug efflux. The effects were mediated by the suppression of NorA mRNA expression and/or interactions with NorA efflux pump. These data support the hypothesis that jatrorrhizine is a potential agent for therapeutic use in infections caused by MRSA.

4.
Global Spine J ; 9(6): 613-618, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31448194

RESUMO

Study Design: Retrospective cohort study. Objective: To assess both implant performance and the amount of correction that can be achieved using multilevel anterior lumbar interbody fusion (ALIF). Methods: Retrospective cohort study (n = 178) performed over a 4-year period. Surgical variables examined included blood loss, operative time, perioperative complications, and secondary/revision procedures. Follow-up radiographic assessment was performed to record implant-related problems. Radiographic parameters were examined pre- and postoperatively. Health-related quality of life (HRQOL) outcome measures were collected preoperatively and at 6 weeks, 6 months, 1 year, and 2 years postoperatively. Descriptive and comparative statistical analysis, using paired-sample t test and repeated-measures analysis of variance (rANOVA), was performed. Results: Lumbar lordosis increased from 42° ± 17° preoperatively to 55° ± 11° postoperatively (P < .001). The visual analog scale back pain mean score improved from 8.3 ± 1.5 preoperatively to 2.6 ± 2.4 at 2 years (P < .001). The mean Oswestry Disability Index improved from 69.5 ± 21.5 preoperatively to 19.9 ± 15.2 at 2 years (P < .001). The EQ-5D mean score improved from 0.2 ± 0.2 preoperatively to 0.8 ± 0.1 at 2 years (P = .02). There were no neurological, vascular, or visceral approach-related injuries reported. No rod breakages and no symptomatic nonunions occurred. There was one revision procedure performed for fracture. Conclusions: The use of porous tantalum cages as part of a 360-degree fusion to treat adult degenerative spinal deformity has been demonstrated to be a safe and effective strategy, leading to good clinical, functional, and radiographic outcomes in the short term.

5.
Orthop Surg ; 11(5): 777-783, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31429532

RESUMO

OBJECTIVE: To study the effect of anti-osteoporosis therapies on mortality after hip fracture. METHODS: This retrospective study was carried out in the Second Affiliated Hospital of Fujian Medical University and enrolled 690 patients 50 years of age and older who were admitted with hip fractures between 2010 and 2015. The patients were followed in 2017: 690 patients aged was from 50 to 103 years. There were 456 women and 234 men. There were 335 patients with fractures of the femoral neck and 355 patients with intertrochanteric fractures of the femur. There were 444 (64.35%) patients who also had internal diseases. The Charlson comorbidity index was 0-6. The anti-osteoporosis medications were classified into no anti-osteoporosis medication, calcium + vitamin D supplementations, non-bisphosphonate medication, and bisphosphonate medication. The physicians followed the patients or family members by personal visit and telephone. Multivariable Cox regression analyses were done with known risk factors for mortality of hip fracture, such as gender, age, number of combined internal diseases, fracture type, place of residence, and Charlson comorbidity index, to show which anti-osteoporosis medications had significant effects on mortality after adjustment for these variables. RESULTS: Out of 690 patients with hip fractures, 149 patients received no anti-osteoporosis medication, 63 patients received calcium +vitamin D supplementations, 398 patients received non-bisphosphonate medication, and 80 patients received bisphosphonate medication. The patients were followed between 7 months and 52 months, with the average of 28.53 ± 9.75 months. A total of 166 patients died during the follow-up period. Of 166 deaths, 43 occurred within 3 months, 65 within 6 months, and 99 within 1 year after the hip fracture. In this study, fracture type, place of residence, and Charlson comorbidity index were not associated with the mortality, and the male gender, age > 75 years, and ≥ 2 combined internal diseases were the independent factors for deaths post-hip fracture. The cumulative mortality was 36.24% in the patients receiving no anti-osteoporosis medication. The hazard ratio for mortality after hip fracture with bisphosphonate medication, non-bisphosphonate medication, and calcium/vitamin D supplementation was 0.355 (95% CI, 0.194-0.648), 0.492 (95% CI, 0.347-0.699) and 0.616 (95% CI, 0.341-1.114), respectively, as compared with no anti-osteoporosis group. Bisphosphonate and non-bisphosphonate medications for osteoporosis were significantly associated with the reduction of cumulative mortality post-hip fracture (P < 0.01). CONCLUSIONS: Bisphosphonate and non-bisphosphonate medications for osteoporosis were significantly associated with decreased mortality after fragility hip fracture.

6.
Nat Nanotechnol ; 14(7): 691-697, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31011219

RESUMO

Spin waves may constitute key components of low-power spintronic devices. Antiferromagnetic-type spin waves are innately high-speed, stable and dual-polarized. So far, it has remained challenging to excite and manipulate antiferromagnetic-type propagating spin waves. Here, we investigate spin waves in periodic 100-nm-wide stripe domains with alternating upward and downward magnetization in La0.67Sr0.33MnO3 thin films. In addition to ordinary low-frequency modes, a high-frequency mode around 10 GHz is observed and propagates along the stripe domains with a spin-wave dispersion different from the low-frequency mode. Based on a theoretical model that considers two oppositely oriented coupled domains, this high-frequency mode is accounted for as an effective antiferromagnetic spin-wave mode. The spin waves exhibit group velocities of 2.6 km s-1 and propagate even at zero magnetic bias field. An electric current pulse with a density of only 105 A cm-2 can controllably modify the orientation of the stripe domains, which opens up perspectives for reconfigurable magnonic devices.

7.
J Cell Biochem ; 120(9): 15280-15287, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31020693

RESUMO

Glioma is an aggressive malignancy with increasing incidence and threatens people's health worldwide. Accumulating evidence revealed that circular RNAs (circRNAs) play important functions in cancers. A previous study demonstrated that circ_001350 was elevated in glioma tissue samples than nontumorous tissue specimens screened by high-throughput microarray. The level of circ_001350 in glioma tissue specimens and cell lines was detected by quantitative real-time polymerase chain reaction. The Fisher exact test was carried out to estimate the correlation of circ_001350 level with clinical characteristics. Cell proliferation, apoptosis, and motility abilities were detected using cell counting kit-8, clonogenic, flow cytometry, and transwell experiments, respectively. The potential target of circ_001350 was identified by the luciferase assay. circ_001350 level was significantly enhanced in glioma tissue specimens and cells. Further, elevated expression of circ_001350 was closely linked to patients' clinical severity. Knockdown of circ_001350 could inhibit cell proliferation and metastatic properties and increase apoptotic cells. circ_001350 could directly bind to miR-1236 and regulate its expression to exert oncogenic functions. Collectively, circ_001350 directly sponges miR-1236, thus contributing to malignant progression of glioma.

8.
Aging Clin Exp Res ; 31(10): 1525-1529, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30560430

RESUMO

BACKGROUND: Fragility fracture significantly increases risk of future fracture. The fragility fracture cycle should be disrupted. The secondary fracture prevention is important for the patients with fragility hip fracture. The pharmacotherapy for osteoporosis is important for prevention of new fracture. However, many patients with hip fracture do not receive osteoporosis treatment. This retrospective study investigates the influence of bone mineral density (BMD) assessment on the initiation of anti-osteoporosis medications in the hospitalized patients with fragility hip fracture. METHODS: This retrospective research enrolled 1211 patients with fragility hip fracture 50 years of age and older. Among 1211 patients aged from 50 to 103 years with the average age of 77.83 ± 9.95 years, there were 807 females and 404 males. There were 634 fractures of femoral neck and 577 intertrochanteric fractures of femur. We examined whether patients had received bone mineral density assessment and received anti-osteoporosis therapy during the period of hospitalization. The patients were divided into BMD assessment group and no BMD assessment group. Measurement data were expressed as mean ± standard deviation and compared with t test. All parameters of groups were compared with Chi-square test. RESULTS: Of 1211 patients, 331 (27.33%) had received BMD assessment and 925 (76.38%) had received anti-osteoporosis drugs during the period of hospitalization. The rate of bisphosphonate use was lower and only 11.31% in the total patients. The anti-osteoporosis treatment rate was 93.66% in the patients receiving BMD assessment and 69.89% in the patients without BMD assessment (p < 0.01). The zoledronate use significantly increased from 6.7% in the patients without BMD assessment to 23.56% in the patients receiving BMD assessment (p < 0.01). CONCLUSIONS: BMD assessment is a good basis for communication between patients and orthopedic surgeons. BMD assessment significantly increases the initiation of osteoporosis treatment and bisphosphonate use in the patients with hip fracture during the period of hospitalization.


Assuntos
Fraturas do Quadril , Osteoporose/tratamento farmacológico , Idoso , Idoso de 80 Anos ou mais , Densidade Óssea , Difosfonatos/uso terapêutico , Feminino , Fêmur , Colo do Fêmur , Fraturas do Quadril/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/prevenção & controle , Estudos Retrospectivos , Prevenção Secundária
9.
Artigo em Inglês | MEDLINE | ID: mdl-31889270

RESUMO

In order to evaluate the dust suppression performance with a spraying system at the fully mechanized excavation face, an airflow-droplet-dust multiphase coupling model was established based on the Eulerian-Lagrangian method. Subsequently, the model's accuracy was validated experimentally using a self-developed system for measuring dust suppression efficiency. For the pressure/exhaust hybrid ventilation condition, the following conclusions can be drawn: with an increase of airflow migration distance, the number of vortices gradually decreased, and dust-capturing probability caused by collision with wall decreased gradually along the axial direction of the roadway. Jointly driven by the rebounded airflow, the entrainment effect of high-velocity jets around the pressure inlet, and the transverse vortex field near the cutting face, three high-concentration dust particle clusters, denoted as particle flows I, II, and III, were formed, and the distribution patterns of dust particle clusters after the implementation of different spray schemes were determined. By analyzing the droplet field distribution surrounding the coal cutting head and comparing the dust suppression performance, the study proposed two optimal spray schemes: with gravity-driven supply of water, the spray scheme K2.0-4 MPa delivered optimum dust suppression performance, and the mean dust concentrations at specific fixed operating points dropped to 130 mg/m3; after utilizing a booster pump, the P2.0-8 MPa spray scheme delivered optimum dust suppression performance, with a mean dust concentration at fixed operating points dropping to 65 mg/m3. After applying the K2.0-4 MPa and P2.0-8 MPa schemes, the dust suppression performance was better for the dust with bigger size. The dust suppression efficiencies for the respirable dust were less than 60.7 and 72.5%, respectively. Other dust prevention measures should be taken to further reduce the dust hazard.

10.
J Cell Biochem ; 2018 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-30387180

RESUMO

Multifidus muscle dysfunction is associated with the multifidus muscle injury (MMI), which ultimately result in the low-back pain. Increasing evidence shows that microRNAs (miRs) may be involved in multifidus muscle dysfunction. In this study, we tested the hypothesis that downregulation of let-7b-5p may inhibit the multifidus muscle dysfunction development and progression. The target prediction program and luciferase activity determination confirmed electron transfer flavoprotein alpha subunit (ETFA) as a direct target gene of let-7b-5p. To study the mechanisms and functions of let-7b-5p in relation to ETFA in MMI progression, we prepared rats with experimental MMI, and a lentivirus-based packaging system was designed to upregulate expressions of let-7b-5p, and downregulate the expression of ETFA. ETFA was identified as a target gene of let-7b-5p. Older age, a longer duration of pain, and higher visual analog scale and Oswestry disability index scores for the patients with chronic low-back pain were linked to a more severe degree of degenerative muscle atrophy and fatty infiltration. Increased expression of let-7b-5p and decreased expression of ETFA and vitamin D receptor (VDR) were positively correlated with multifidus muscle dysfunction. Downregulated let-7b-5p could inhibit infiltration of collagen fibers, reverse the ultrastructural changes of multifidus muscle, and induce the VDR expression, thereby repair the MMI. The results provided a potential basis for let-7b-5p that could support targeted intervention in multifidus muscle dysfunction. Collectively, this study confirmed that downregulation of let-7b-5p has a potential inhibitory effect on the development of the function of the musculus myocytes by upregulating ETFA.

11.
Clin Neurol Neurosurg ; 175: 149-154, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30447607

RESUMO

OBJECTIVE: Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction. Our study aims to explore the correlation of osteoprotegerin (OPG) gene polymorphisms and the risk factors and severity of CSM. PATIENTS AND METHODS: The peripheral blood samples from 494 CSM patients and 515 healthy individuals were collected for detecting the 950T/C, 1181G/C and 163A/G genotypes and genetic equilibrium of OPG in the CSM and control groups and analyzing the genotype distribution and allele frequency. The severity of CSM and the impaired segments were evaluated by the Japanese Orthopedic Association (JOA) scoring combined with cervical magnetic resonance imaging (MRI), in order to investigate the relations between the three genotypes of OPG promoter gene loci (950T/C, 163A/G and 1181G/C) and occurrence as well as severity of CSM. RESULTS: The risk rate of TC genotype carrier suffered from CSM was 0.46, of TT genotype carrier was 0.27. The risk rate of T allele carrier suffered from CSM was 0.37. In 950T/C single nucleotide polymorphism (SNP), patients with TC, TT and T genotypes had lower risk to suffer from CSM. CONCLUSION: Taken together, OPG 950T/C SNP protects against CSM, and it is correlated with the severity of CSM, providing a new idea for the prevention and treatment of CSM.


Assuntos
Grupo com Ancestrais do Continente Asiático/genética , Predisposição Genética para Doença/genética , Osteoprotegerina/genética , Polimorfismo de Nucleotídeo Único/genética , Doenças da Medula Espinal/genética , Espondilose/genética , Adulto , Vértebras Cervicais/diagnóstico por imagem , Feminino , Predisposição Genética para Doença/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Vigilância da População/métodos , Doenças da Medula Espinal/diagnóstico por imagem , Doenças da Medula Espinal/epidemiologia , Espondilose/diagnóstico por imagem , Espondilose/epidemiologia , Adulto Jovem
12.
Biochem Biophys Res Commun ; 507(1-4): 260-266, 2018 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-30442366

RESUMO

Osteosarcoma is the most common primary bone tumor and occurs most frequently in adolescents. Cancer stem cells (CSCs) are resistant to chemotherapy and radiotherapy, and can drive cancer recurrence. In this study, we aimed to investigate the effect of Long noncoding RNAs (lncRNAs) DLX6-AS1 on osteosarcoma stemness and the underlying mechanism involved. DLX6-AS1 enhanced osteosarcoma stemness in vitro and in vivo. Moreover, DLX6-AS1 competitively interacted with miR-129-5p to DLK1, resulting in activation of Wnt signaling and promotion of stemness in osteosarcoma. DLX6-AS1 functionally interplayed with miR-129-5p to form a reciprocal feedback loop to activate Wnt signaling. High DLX6-AS1 expression was observed in osteosarcoma tissues, and predicted a poor prognosis for osteosarcoma patients. Our study suggests that DLX6-AS1, combined with miR-129-5p and DLK1, can be utilized as factors for the clinical diagnosis and prognosis of osteosarcoma, and may be potential targets for the treatment of osteosarcoma.


Assuntos
Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , MicroRNAs/metabolismo , Células-Tronco Neoplásicas/patologia , Osteossarcoma/genética , Osteossarcoma/patologia , RNA Longo não Codificante/metabolismo , Via de Sinalização Wnt/genética , Animais , Proteínas de Ligação ao Cálcio , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/genética , Células-Tronco Neoplásicas/metabolismo , Prognóstico , Ligação Proteica , RNA Longo não Codificante/genética , Análise de Sobrevida , Regulação para Cima/genética
13.
BMC Musculoskelet Disord ; 19(1): 235, 2018 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-30021567

RESUMO

BACKGROUND: Vertebral fracture is the most common fragility fracture but it remains frequently unrecognized and is underdiagnosed worldwide. In this retrospective study, we examined the prevalence of moderate and severe vertebral fractures on chest radiographs of hospitalized female patients aged 50 years and older and determined missed diagnosis of vertebral fractures in the original radiology reports. METHODS: 3216 female patients 50 years of age and older were enrolled in our study. The patients' medical records including their original radiology reports and lateral chest radiographs were retrospectively reviewed by the study radiologists who had training certificates from the International Society for Clinical Densitometry (ISCD). Vertebral fractures between thoracic spine T4 and lumbar spine L1 were identified and classified using Genant's semi-quantitative scale. The definition of vertebral fractures used in this study was Genant grade 2 or higher. RESULTS: The study radiologists identified 295(9.2%) patients with grade 2 or 3 fractured vertebrae, total 444 vertebrae on 3216 chest radiographs. The prevalence of vertebral fracture was 2.4% in women aged 50-59 yrs., 8.9% in women aged 60-69 yrs., and 21.9% in women aged≥70 yrs. There were 213 patients with a single vertebral fracture, 49 patients with two vertebral fractures and 33 patients with ≥ three vertebral fractures. Fractured vertebrae were identified with greater frequency in thoracic spine T11,12 and lumbar spine L1. According to our statistics, 66.8% of patients with vertebral fractures found in this study were undiagnosed in the original radiology reports. CONCLUSIONS: Vertebral fracture is common on chest radiographs but it is often ignored by radiologists. Genant's semiquantitative assessment is a simple and effective method for detecting vertebral fracture. Because osteoporotic vertebral fracture increases the risk of new fractures, radiologists have an important role in accurately diagnosing vertebral fractures.


Assuntos
Vértebras Lombares/diagnóstico por imagem , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/epidemiologia , Vértebras Torácicas/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pessoa de Meia-Idade , Prevalência , Estudos Retrospectivos , Tórax/diagnóstico por imagem
14.
Environ Sci Pollut Res Int ; 25(27): 27141-27154, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30022392

RESUMO

In order to ensure safe production and occupational health at a large-mining-height fully mechanized mining face in a coal mine, the present study firstly establishes an airflow-dust coupled model based on gas/solid two-phase flow equations and combines numerical simulation and field measurement for analyzing the dispersion pattern of dust particles with various sizes for different coal cutter locations. Results show that, due to the existence of drums, airflow deviates from the original direction and enters the footway. Driven by the airflow, dust particles enter the footway at different locations depending on coal cutter locations. The coal-cutting location (denoted as Prl) and the location where dust particles enter the footway (denoted as Pdt) are correlated as follows: Pdt(Prl) = - 0.0007Prl2 + 1.0343Prl - 3.3536. When Prl < 55 m, dust particles produced by the rear drum during coal cutting enter the footway earlier than those produced by the front drum, leading to the first and second dust concentration peaks in respiratory zones of footway. Dust suppression effects are assessed in these regions based on the first and second dust concentration peaks. Due to the superposition of the concentration fields associated with dust particles 2.5, 7, and 20 µm in diameter, dust concentration 25 m down the leeward side of the coal cutter can reach 1440 mg/m3. The concentration of dust particles with a diameter of 40 µm drops steadily and approaches 0 at the return corner. The dust particles 80 µm in diameter are fully settled within 22 m down the leeward side of the coal cutter. A comparison with the field measurement indicates that the present simulation results are highly accurate. Graphical abstract.


Assuntos
Movimentos do Ar , Minas de Carvão , Poeira/análise , Modelos Teóricos , Carvão Mineral/análise , Simulação por Computador , Humanos , Exposição Ocupacional , Saúde do Trabalhador
15.
Phys Rev Lett ; 120(21): 217202, 2018 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-29883138

RESUMO

We observe strong interlayer magnon-magnon coupling in an on-chip nanomagnonic device at room temperature. Ferromagnetic nanowire arrays are integrated on a 20-nm-thick yttrium iron garnet (YIG) thin film strip. Large anticrossing gaps up to 1.58 GHz are observed between the ferromagnetic resonance of the nanowires and the in-plane standing spin waves of the YIG film. Control experiments and simulations reveal that both the interlayer exchange coupling and the dynamical dipolar coupling contribute to the observed anticrossings. The coupling strength is tunable by the magnetic configuration, allowing the coherent control of magnonic devices.

16.
Environ Sci Pollut Res Int ; 25(22): 21768-21788, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29796880

RESUMO

In order to investigate the diffuse pollution mechanisms of high-concentration dusts in the blasting driving face, the airflow-dust coupled model was constructed based on CFD-DEM coupled model; the diffusion rules of the dusts with different diameters at microscopic scale were analyzed in combination with the field measured results. The simulation results demonstrate that single-exhaust ventilation exhibited more favorable dust suppression performance than single-forced ventilation. Under single-exhaust ventilation condition, the motion trajectories of the dusts with the diameter smaller than 20 µm were close to the airflow streamline and these dusts were mainly distributed near the footway walls; by contrast, under single-forced ventilation condition, the motion trajectories of the dust particles with a diameter range of 20~40 µm were close to the airflow streamlines, and a large number of dusts with the diameter smaller than 20 µm accumulated in the regions 5 m and 17~25 m away from the head-on section. Moreover, under the single-exhaust ventilation, the relationship between dust diameter D and negative-pressured-induced dust emission ratio P can be expressed as P = - 25.03ln(D) + 110.39, and the dust emission ratio was up to 74.36% for 7-µm dusts, and the path-dependent settling behaviors of the dusts mainly occurred around the head-on section; under single-forced ventilation condition, the z value of the dusts with the diameter over 20 µm decreased and the dusts with a diameter smaller than 7 µm are particularly harmful to human health, but their settling ratios were below 22.36%. Graphical abstract The airflow-dust CFD-DEM coupling model was established. The numerical simulation results were verified. The migration laws of airflow field were obtained in a blasting driving face. The diffusion laws of dusts were obtained after blasting.


Assuntos
Poluição do Ar/análise , Poeira/análise , Mineração/métodos , Modelos Teóricos , China , Simulação por Computador , Difusão , Humanos , Exposição Ocupacional/análise , Ventilação
17.
ACS Appl Mater Interfaces ; 10(19): 16887-16892, 2018 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-29682962

RESUMO

In this work, we demonstrate that skyrmions can be nucleated in the free layer of a magnetic tunnel junction (MTJ) with Dzyaloshinskii-Moriya interactions (DMIs) by a spin-polarized current with the assistance of stray fields from the pinned layer. The size, stability, and number of created skyrmions can be tuned by either the DMI strength or the stray field distribution. The interaction between the stray field and the DMI effective field is discussed. A device with multilevel tunneling magnetoresistance is proposed, which could pave the ways for skyrmion-MTJ-based multibit storage and artificial neural network computation. Our results may facilitate the efficient nucleation and electrical detection of skyrmions.

18.
Exp Ther Med ; 15(3): 2295-2300, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29456636

RESUMO

Chronic obstructive pulmonary disease (COPD) is characterized by progressive airflow limitation and loss of lung function. The present study aimed to investigate the diaphragmatic protein expression of myostatin and its correlation with apoptosis in a rat model of CPOD. Sprague Dawley rats were randomly divided into a control group and a COPD group, the latter of which were exposed to cigarette smoke to build a rat model of COPD. The validity of the COPD model was evaluated by assessment of lung function and histopathological analysis. Diaphragmatic myostatin expression and apoptosis were measured by western blot and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling, respectively. The rat model of COPD was efficiently established by cigarette smoke exposure. Diaphragmatic myostatin expression and apoptotic index in COPD rats were obviously increased as compared with that in the control animals. A positive correlation between diaphragmatic myostatin expression and apoptotic index was identified (r=0.857). Diaphragmatic myostatin overexpression in rats with COPD may promote diaphragmatic apoptosis and atrophy, leading to diaphragm weakness and respiratory muscle dysfunction, which is involved in the pathology of COPD.

19.
Orthop Surg ; 10(1): 17-22, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29430846

RESUMO

OBJECTIVE: To investigate the effect of grip strength on bone mineral density (BMD) in postmenopausal women. Low BMD is related to risk of fracture and falling is the strongest factor for fragility fractures. Handgrip strength is a reliable indicator of muscle strength and muscle strength is associated with falling. METHODS: For the present study 120 women were divided into two groups: those ≤65 years and those >65 years. Serum 25 hydroxyvitamin D (25OHD), BMD, and handgrip strength were measured to observe the effect of age on 25OHD, grip strength, and BMD, as well as the effect of 25OHD on grip strength and BMD. The correlation between grip strength and BMD was investigated. RESULTS: In the 120 patients, 25OHD was 24.31 ± 8.29 ng/mL. There were 37 cases with 25OHD <20 ng/mL and 83 cases with 25 OHD ≥20 ng/mL. The patients with 25OHD <20 ng/mL had significantly lower femoral neck BMD, most of them with a T score ≤-2.5 (P < 0.05). BMD measurement showed 66 patients with femoral neck T ≤-2.5, 30 cases with total hip T ≤-2.5 and 90 cases with lumbar BMD T ≤-2.5. The maximum grip strength in the group is 22.28 ± 6.17 kg. There were 38 cases with the maximum grip strength <20 kg and 82 cases with the maximum grip strength ≥20 kg. Patients >65 years had lower 25OHD, lower maximum grip strength, and lower BMD. The osteoporosis risk in postmenopausal women with a maximum grip strength <20 kg and who were >65 years was significantly elevated. CONCLUSION: Handgrip strength and 25OHD decrease with aging in postmenopausal women. The patients with lower 25OHD level had significantly lower BMD of femoral neck. The patients with lower handgrip strength had significantly lower BMD of lumbar spine, femoral neck, and total hip. Grip strength measurement is the simplest muscle strength measurement method. Our study confirmed that low grip strength was correlated with low BMD and was a strong risk factor for osteoporosis in postmenopausal women.


Assuntos
Densidade Óssea/fisiologia , Força da Mão/fisiologia , Osteoporose Pós-Menopausa/fisiopatologia , Acidentes por Quedas/estatística & dados numéricos , Idoso , Envelhecimento/sangue , Envelhecimento/fisiologia , Feminino , Colo do Fêmur/fisiopatologia , Articulação do Quadril/fisiopatologia , Humanos , Vértebras Lombares/fisiopatologia , Pessoa de Meia-Idade , Força Muscular/fisiologia , Osteoporose Pós-Menopausa/sangue , Osteoporose Pós-Menopausa/complicações , Fraturas por Osteoporose/etiologia , Fraturas por Osteoporose/fisiopatologia , Pós-Menopausa/sangue , Pós-Menopausa/fisiologia , Fatores de Risco , Vitamina D/análogos & derivados , Vitamina D/sangue
20.
Nat Commun ; 9(1): 738, 2018 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-29467416

RESUMO

Recent years have witnessed a rapidly growing interest in exploring the use of spin waves for information transmission and computation toward establishing a spin-wave-based technology that is not only significantly more energy efficient than the CMOS technology, but may also cause a major departure from the von-Neumann architecture by enabling memory-in-logic and logic-in-memory architectures. A major bottleneck of advancing this technology is the excitation of spin waves with short wavelengths, which is a must because the wavelength dictates device scalability. Here, we report the discovery of an approach for the excitation of nm-wavelength spin waves. The demonstration uses ferromagnetic nanowires grown on a 20-nm-thick Y3Fe5O12 film strip. The propagation of spin waves with a wavelength down to 50 nm over a distance of 60,000 nm is measured. The measurements yield a spin-wave group velocity as high as 2600 m s-1, which is faster than both domain wall and skyrmion motions.

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