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The resolution limitation is a main problem in the time-reversed field shaping system. In this paper, a subwavelength field shaping approach is proposed by combining time reversal (TR) technique and defective resonant metasurfaces. The subwavelength 2D and 3D field patterns can be effectively realized in both single-target and multi-target field-shaping systems. The resolution in both single-target and multi-target field-shaping systems aided with defective metasurfaces is approximately $0.1~\lambda $ , which is corresponding to the dimension of the applied metasurface cell. The proposed technique can be used for wireless power transfer, industrial heating, and localized wireless communications.

[Purpose] The purpose of this study was to investigate the relationship of various aspects of daily physical activity, such as the number of steps, time spent in moderate to vigorous intensity physical activity (MVPA), and locomotive and non-locomotive MVPA measured by a triaxial accelerometer, with the functional fitness in healthy elderly men. [Methods] The subjects of this study were 22 healthy elderly men aged over 65 years. The participants wore a triaxial accelerometer for two weeks to estimate their daily physical activities. The level of functional fitness was measured based on "National Fitness Award 100 in Korea" immediately after the measurement of two weeks of daily physical activities. [Results] The results showed that active healthy elderly men with more than 6,500 walking steps per day and more than 60 min per day spent in MVPA showed a significantly higher 2-min marching in place and index of cardiorespiratory endurance compared to less physically active participants. Particularly, locomotive MVPA was significantly associated with cardiorespiratory endurance levels (r = 0.50), whereas non-locomotive MVPA was not associated with other measurements of functional fitness. [Conclusion] Increased MVPA time, especially the locomotive MVPA, can effectively suppress the decrease in cardiorespiratory endurance level in elderly men. However, no association was observed between non-locomotive MVPA, such as household activities, and functional fitness in healthy elderly men.

Background The adverse effects of TI exposure on pregnant women are still unclear, especially regarding the risk of gestational diabetes mellitus (GDM) Objective: We explored the association between maternal urinary Tl burden and the risk of GDM. Methods A subsample of 1789 pregnant women were enrolled who provided spot urine samples before the diagnostic 75-g oral glucose tolerance test. Urinary Tl concentration was measured using inductively coupled plasma mass spectrometry. Logistic regression and covariance analysis were carried out to estimate the association between Tl exposure and GDM risk. Results The median of urinary Tl concentration was 0.382 μg/L or 0.525 μg/g creatinine (CC–Tl). There were 437 (24.4%) participants who were diagnosed with GDM, and the urinary CC-Tl concentrations of pregnant women with GDM were higher than that of pregnant women without GDM [0.548 (0.402, 0.788) vs 0.518 (0.356, 0.724), p = 0.014]. After adjusting for the relevant covariates, an association between urinary Tl concentrations and GDM was found. In comparison to the pregnant women in the lowest quartile of urinary CC-Tl concentration, the pregnant women in the highest quartile had a higher risk of GDM [OR (95% CI) = 1.44 (1.03, 2.02), p-trend = 0.055]. If limited to the pregnant women without family history of diabetes, the results were still robust [OR (95% CI) = 1.59 (1.11, 2.30), p-trend = 0.012]. Conclusion Urinary CC-Tl concentration was associated with GDM among Chinese pregnant women. Our findings provide evidence that moderately high Tl exposure may be a novel risk factor for pregnant women health.

The organic-inorganic hybrid perovskite has become a new type of semiconductor for low cost and highly efficient solar cells. However, the mechanism of interactions between the organic cation and the inorganic framework is still not completely clear under optical electronic excitation. In this work, we employ first-principles molecular dynamics with electronic excitation effects to prove that the hydrogen-bond interaction between the molecular cation and the inorganic lattice can be readily adjusted by several-percentage-valence-electron excitations in cubic CH3NH3PbI3. While the hydrogen-bond interaction causes serious lattice distortions, the electronic excitation can recover the lattice symmetry largely by weakening hydrogen bonding. The study offers atomic dynamics to understand the excitation process in the organic-inorganic hybrid perovskite semiconductor.

The reflection characteristics of flying electromagnetic toroid (FET) pulses on an inclined air-metal interface are numerically analyzed and compared with the performance of the free-space FET pulses in this paper. The structural stability and field component transformation characteristics of the FET pulses are firstly found from the reflected pulses on an inclined metallic surface, which provides a physical basis for the application of the FET pulses in complex reflection scenarios.

The propagation characteristics of flying electromagnetic toroid (FET) pulses are discussed under the condition of partial absorption boundary and the encounter of scattering bodies in the propagation path. We demonstrate that the longitudinal partial absorption boundary can lengthen the non-diffraction section of FET and FET has the structure self-repairing property. The characteristics that we demonstrate have broad application prospects in the fields of energy transmission, particle acceleration and longitudinal multistage imaging

As a new kind of electromagnetic pulses with finite energy, the flying electromagnetic toroid (FET), also called as the flying electromagnetic doughnut, has significant potential applications, such as the excitation of anapole non-radiation mode and the acceleration of charged particles. To show the propagation characteristic of FET, the spatial distribution and spectrum characteristic of the transverse and longitudinal components of FET and its topology evolution in the propagation process are discussed in this paper. Without loss of generality, we theoretically research the longitudinal field and transverse field of the transverse magnetic (TM) FET based on the real part of FET’s propagation equations. The field distribution, topology, and spectrum when the FET propagates to different positions can be calculated by assigning corresponding values to the time variable in FET’s propagation equations, therefore, the propagation characteristics of FET can be studied accurately in theory. The magnetic field of TM FET is distributed into rings in the plane vertical to the propagation direction and the electric field of TM FET is rotated around the magnetic field, which means the FET has a hypertorus topology. All the field components of FET are rotationally symmetric in the plane vertical to the propagation direction. The FET’s center is the maximum position of the longitudinal electric field component and the null position of the transverse electric and magnetic field components. Maximum values of FET’s longitudinal field are always located on the central line of FET’s propagation path and decrease gradually in the propagation process. Different from the longitudinal field, the maximum value of FET’s transverse field gradually moves away from FET’s center. The theoretical research indicates that the FET spreads quite slowly in its early propagation state and spreads linearly after propagating a long distance, which has the slowly spreading propagation characteristic even in the so-called focused range with stable toroidal topological structure. The further spectrum analysis shows that the high-frequency components spread less than the low-frequency components and the high-frequency components play a vital role in the topology retention of FET in the focused range, which may provide a basis for the generation and application of FET. At present, the theoretical research on FET’s characteristics is increasingly improved. To apply the attractive characteristics of FET in actual systems, it is necessary to actually generate FET. Therefore, the generation method of FET should become the next research emphasis.

본 연구는 대형항공사 국제선 객실승무원의 수면의 질, 피로 및 직무스트레스를 파악하고 직무스트레스에 미치는 영향요인을 확인하기 위한 서술적 상관관계 조사연구이다. 연구결과 직무스트레스에 유의한 영향을 주는 인구학적 변수는 성별, 직급, 한 달 비행시간, 건강보조식품 복용유무, 수면유도제 복용유무였다. 직무스트레스와 수면의 질은 음의 관계 (r=-.57, p

Aims Mesenchymal stem cells (MSCs) have been demonstrated to be protective in diabetic nephropathy (DN) by reducing albuminuria and attenuating glomerular injury. However, the mechanisms remain unclear. The aim of this study was to explore the effects of MSCs on oxidative stress in DN. Materials/methods Streptozotocin-induced diabetic rats received no treatment or treatment with MSCs (2 × 106, via tail vein) for two continuous weeks. Two other control groups received the antioxidant-probucol or insulin. Eight weeks after treatment, physical, biochemical, renal functional and morphological parameters were measured. Glomerular mesangial cells were cultured for the in vitro experiment. Results Green fluorescent protein-labeled MSCs were only detected around the glomeruli and near vessels in the kidney. MSCs treatment dramatically reduced blood glucose, urinary albumin excretion, creatinine clearance and renal mass index. The glomerulosclerosis as revealed by periodic acid Schiff staining and expression of collagen I and fibronectin was significantly reduced by MSC treatment. Oxidative stress was also markedly inhibited in the MSCs group. Furthermore, the expression of TGF-β and membrane localization of GLUT1 were also down-regulated by MSCs. MSCs secreted a significant amount of hepatocyte growth factor (HGF). In vitro, MSC conditioned medium inhibited up-regulation of TGF-β expression stimulated by high glucose and HGF neutralizing antibody blocked the inhibitory effect of MSC conditioned medium. Conclusions MSC treatment reduced urinary albumin excretion and ameliorated glomerulosclerosis. The mechanisms underlying these effects involved reduced blood glucose levels and cellular glucose uptake mediated by GLUT1, thus inhibiting oxidative stress.

A novel scheme with a tapered channel attached to an ultra-thin carbon foil is proposed to accelerate and guide carbon ions via breakout afterburner mechanism. Also, the problems involved are investigated by using two-dimensional particle-in-cell simulations. It is demonstrated that the tapered channel can efficiently accelerate and guide carbon ions and result in a much better quality beam with an order of magnitude higher in density and 22% larger in cut-off energy than that without the tapered channel. The enhanced reasons are analyzed in detail, which are mainly attributed to the guidance of the longitudinal electric field and the focus of the transverse electric field, as well as the convergence effect of the tapered channel. All of them are certified to guide greatly carbon ions to move along the longitudinal direction. Besides, during the simulation time, the ion beam with a tapered channel can remain eight times smaller in divergence angle than that without the tapered channel. Such a target may be beneficial to many applications such as ion fast ignition in inertial fusion, high-energy physics, and proton therapy.

A low-density-core target with buried high density layers is proposed to improve the transport of fast electrons and involved problems are investigated by using two-dimensional particle-in-cell simulations. It is demonstrated that this target can collimate the fast electrons efficiently and lead to a better beam quality. The enhancement is attributed to the weakening of the two stream instability and the better collimation by the self-generated multilayer megagauss magnetic field as well as the baroclinic magnetic field. Comparing this to that without buried high density layers, the energy flux of fast electrons is increased by a factor of about 1.8 and has a narrower transverse distribution in space. Besides, the dependence of the efficiency on the target parameters is examined, and the optimal target parameters are also obtained. Such a target can be useful to many applications, such as fast ignition in inertial fusion.

Mesenchymal stem cells (MSCs) treatment has been shown to be effective in diabetic nephropathy (DN). However, the mechanisms involved in the renoprotective effects of MSCs have not been clearly demonstrated. Especially, there was no study on the relationship of MSCs and macrophages in diabetic kidney. To explore the effect of MSCs on macrophages in DN, streptozotocin-induced diabetes animals received no treatment or treatment with MSCs (2×10(6), via tail vein) for two continuous weeks. Eight weeks after treatment, physical, biochemical and morphological parameters were measured. Immunohistochemistry for fibronectin (FN), CollagenI, ED-1, monocyte chemoattractant protein-1 (MCP-1) was performed. Expressions of pro-inflammatory cytokines and hepatocyte growth factor (HGF) at gene level and protein level were determined by real-time reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Blood glucose, urinary albumin excretion, creatinine clearance were significantly reduced after MSCs treatment. The glomerulosclerosis as revealed by periodic acid Schiff stain and expression of FN and CollagenI was also dramatically attenuated. Most importantly, the expression of MCP-1 and the number of infiltrated macrophages in kidney were effectively suppressed by MSCs treatment. The expression of HGF in MSCs group was up-regulated. Meanwhile, the expressions of IL-1β, IL-6 and TNFα were significantly down-regulated by MSCs treatment. Our study suggest that MSCs treatment ameliorates DN via inhibition of MCP-1 expression by secreting HGF, thus reducing macrophages infiltration, down-regulating IL-1β, IL-6, TNFα expression in renal tissue in diabetic rats.

Optical properties of metal nano-materials is based on the shape, In this paper, firstly, relationships between scattering efficiency and the incident light wavelength of iron nanoparticles with diameter of 20nm, 40nm, 60nm, 80nm, 100nm were calculated with Mie plot and DDA. The results show that DDA algorithm and program design and parameter settings are accurate. Then scattering efficiency of iron nanorods is calculated by DDA, diameters are 10nm, 20nm, 30nm with different aspect ratio and different incident light wavelength, and relationship between aspect ratio and the scattering efficiency is also analysed. This work will contribute to the exploration of the other optical properties of iron nanorods, and provide the theoretical basis of application.