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Background: The key circular RNAs (circRNAs) and the molecular mechanisms by which they regulate the progression of acute myeloid leukemia (AML) in adults are unclear.Methods: We used a circRNA microarray to analyze the differentially expressed circRNAs in peripheral blood mononuclear cells of newly diagnosed adult AML patients. Reverse transcription-PCR, fluorescence in situ hybridization, Sanger sequencing, and ribonuclease R tests were used to examine circRNF220 loop formation and stability and its potential value in AML diagnosis. Cell Counting Kit-8, flow cytometry, and subcutaneous tumor assays were used to detect the effects of circRNF220 on the proliferation and apoptosis of the HL-60 and THP-1 cell lines. RNA antisense purification, methylated RNA immunoprecipitation, and RNA pull-down assays were used to identify circRNF220-binding proteins and microRNAs.Results: CircRNF220 was located in the cytoplasm and was more stable than linear RNF220. The area under the curve value of circRNF220 for the diagnosis of AML was 0.8314. Silencing circRNF220 expression inhibited the growth and promoted the early apoptosis of HL-60 and THP-1 cells. CircRNF220 had no competitive endogenous relationship with microRNAs. The RNA methylase FTO regulated the demethylation and expression of circRNF220. The RNA-binding protein serine/arginine-rich splicing factor 1 (SRSF1) and circRNF220 co-localized in the cytoplasm, and circRNF220 promoted SRSF1 expression. Furthermore, silencing circRNA220 reduced the tumorigenicity of AML cells in vivo.Conclusions: CircRNF220 is a potential biomarker for the diagnosis of adult AML. FTO mediates circRNF220 demethylation. and circRNF220 binds to SRSF1 to promote the progression of AML.

BACKGROUND Treatments utilizing stems cells often require stem cells to be exposed to inflammatory environments, but the effects of such environments are unknown. AIM To examine the effects of inflammatory cytokines on the morphology and quantity of mesenchymal stem cell exosomes (MSCs-exo) as well as the differential expression of microRNAs (miRNAs) in the exosomes. METHODS MSCs were isolated from human umbilical tissue by enzymatic digestion. Exosomes were then collected after a 48-h incubation period in a serum-free medium with one of the following the inflammatory cytokines: None (control), vascular cell adhesion molecule-1 (VCAM-1), tumor necrosis factor (TNF) α, and interleukin (IL) 6. The morphology and quantity of each group of MSC exosomes were observed and measured. The miRNAs in MSCs-exo were sequenced. We compared the sequenced data with the miRBase and other non-coding databases in order to detect differentially expressed miRNAs and explore their target genes and regulatory mechanisms. In vitro tube formation assays and Western blot were performed in endothelial cells which were used to assess the angiogenic potential of MSCs-exo after inflammatory cytokine stimulation. RESULTS MSCs-exo were numerous, small, and regularly shaped in the VCAM-1 group. TNFα stimulated MSCs to secrete larger and irregular exosomes. IL6 led to a reduced quantity of MSCs-exo. Compared to the control group, the TNFα and IL6 groups had more downregulated differentially expressed miRNAs, particularly angiogenesis-related miRNAs. The angiogenic potential of MSCs-exo declined after IL6 stimulation. CONCLUSION TNFα and IL6 may influence the expression of miRNAs that down-regulate the PI3K-AKT, MAPK, and VEGF signaling pathways; particularly, IL6 significantly down-regulates the PI3K-AKT signaling pathway. Overall, inflammatory cytokines may lead to changes in exosomal miRNAs that abnormally impact cellular components, molecular function, and biological processes.

Based on the phase-change material Ge2Sb2Te5 (GST), achromatic metasurface optical device in the longer-infrared wavelength is designed. With the combination of the linear phase gradient GST nanopillar and the adjustment of the crystalline fraction m value of GST, the polarization insensitive achromic metalenses and beam deflector metasurface within the longer-infrared wavelength 9.5 μm to 13 μm are realized. The design results show that the achromatic metalenses can be focused on the same focal plane within the working waveband. The simulation calculation results show that the full-width at half-maximum (FWHM) of the focusing spot reaches the diffraction limit at each wavelength. In addition, the same method is also used to design a broadband achromatic beam deflector metasurface with the same deflection angle of 19°. The method proposed in this article not only provides new ideas for the design of achromatic metasurfaces, but also provides new possibilities for the integration of optical imaging, optical coding and other related optical systems.

Background: Diabetic foot is caused by ischemic disease of lower extremities of diabetic patients, and the effective therapy is very limited. Mesenchymal stem cells (MSCs) based cell therapy had been developed into a new treatment strategy for diabetic foot clinically. However, the underlying molecular mechanism remains to be fully addressed. Exosomes secreted by MSCs may play crucial role in the processes of MSCs mediated inhibition of inflammatory microenvironment as well as pro-angiogenesis of ischemic tissue of diabetic foot. Methods: Exosomes were isolated from MSCs using ultra-high centrifugation, and further characterized by the nanoparticle tracking analyzer and flow cytometry. Moreover, RNA sequencing, Western Blot, in vitro cell proliferation, in vivo pro-angiogenesis, as well as ischemic repairment of diabetic foot through rat model were performed to evaluate exosome physiological functions. Results: We found that different inflammatory cytokines (tumor necrosis factor a, vascular cell adhesion molecule-1 and interleukin-6) induced MSCs to secrete exosomes heterogeneously, including exosome size and quantity. Through RNA sequencing, we defined a new proangiogenic miRNA, miRNA-21-5p. Further knockdown and overexpression of miRNA-21-5p by manipulating MSCs validated the biological activity of exosome miRNA-21-5p, including in vitro cell proliferation, in vivo pro-angiogenesis in Chick Chorioallantoic Membrane (CAM) assay, and in vivo pro-angiogenesis experiments (tissue injury and repair) in diabetic rat models. Furthermore, we discovered that exosomemiRNA-21-5p promoted angiogenesis through upregulations of vascular endothelial growth factor receptor (VEGFR) as well as activations of serine/threonine kinase (AKT) and mitogen-activated protein kinase (MAPK). Together, our work suggested miRNA-21-5p could be a novel mechanism by which exosomes promote ischemic tissue repairing and angiogenesis. Meanwhile, miRNA-21-5p could be potentially developed into a new biomarker for exosomes of MSCs to treat diabetic foot. Conclusions: miRNA-21-5p is a new biomarker and a novel mechanism by which exosomes promote ischemic tissue repairing and angiogenesis of diabetic foot. Our work could not only provide new scientific evidences for revealing pro-angiogenesis mechanism of MSCs, but also eventually benefit MSCs-based clinical therapy for diabetic foot of diabetes patients.

Three vortex-focused beams are produced with linearly polarized light along the x or y axis at a wavelength of 1550 nm. First, a polarization-independent vortex metalens with a topological charge of three and focal length of 3000 nm is designed by selecting cylindrical-shaped elements. This design has a focusing efficiency of 83%. Second, vortex beams with different focal lengths and topological charges are achieved by combining various shapes of structures. Both designs have a focusing efficiency of greater than 92%. The designed metasurface is of great significance to optical communication and radar detection.

Three-dimensional (3D) materials are widely used in optoelectronics, thermodynamics and ultrafast fiber lasers because of their excellent nonlinear optical properties. Silver sulfide (Ag

Two-dimensional layered metal chalcogenides (LMCs) are widely used in battery anode materials, energy conversion, and semiconductor devices, because of their high energy storage characteristics, high thermoelectric characteristics, and large electron mobility. SnSe

A tunable metalens plays an indispensable role in the development of integrated optics, multi-imaging systems, etc. We propose a multifunctional tunable metalens that combines a double-layer barium titanate (BTO) structure and geometric phase in the visible light band. The refractive indices of the upper and lower layer BTO nanorods can be tuned continuously and independently by applying external voltage (0–60 V), and the lower layer can be converted between a full-wave plate and normal scattering unit, while the scatterers of the upper layer can be switched between a half-wave plate and full-wave plate. The voltages of the upper and lower layers can be adjusted to achieve different functions such as optical switches, conversion between monofocal and bifocal metalenses, adjustment of bifocal intensity, and broadband focusing (585–690 nm). Simulation results show that the multifunctional tunable metalens has a good focusing effect. A metalens with high focusing efficiency, dynamic reconfigurability, and a switching function has tremendous application potential in the fields of multifunctional devices, biomedicine, optical communication, imaging, and so on.

OBJECTIVE This study aimed to explore the correlation of long non-coding RNA taurine-upregulated gene 1 (lncRNA TUG1) expression with clinicopathological features and its predictive value for treatment response and survival profiles in refractory or relapsed acute myeloid leukemia (R/R AML) patients. METHODS Seventy three R/R AML patients who received cladribine combined with cytarabine and granulocyte colony-stimulating factor (G-CSF) (CLAG) or fludarabine combined with cytarabine and G-CSF (FLAG) based chemotherapy and 37 non-malignant controls were recruited. LncRNA TUG1 expression was detected in bone marrow sample obtained before treatment. Complete response (CR), partial response (PR), overall response rate (ORR) and overall survival (OS) were evaluated. RESULTS LncRNA TUG1 expression was upregulated in R/R AML patients compared to controls. It was also elevated in R/R AML patients with age ⩾ 60 years (vs. age < 60 years, P= 0.030) and in patients with secondary AML (vs. primary AML, P= 0.035). R/R AML patients with lncRNA TUG1 high expression achieved numerically lower CR (P= 0.053), decreased ORR (P= 0.028) and shorter OS (P< 0.001) than patients with lncRNA TUG1 low expression. Univariate logistic regression and COX's regression disclosed that lncRNA TUG1 high expression correlated with declined ORR, numerically decreased CR, and reduced OS. Furthermore, multivariate analyses verified that lncRNA TUG1 high expression was an independent predictive factor for decreased ORR and worse OS. CONCLUSIONS In conclusion, lncRNA TUG1 expression was elevated in R/R AML patients, and it might serve as a potential biomarker for poor prognosis in R/R AML patients treated with CLAG or FLAG based chemotherapy.

The relays used in aviation electronic equipment are required to have extremely high reliability. Due to strong shock and vibration in the service process, premature failure of reeds in aviation relays is a common problem. Nonetheless, limited published investigations focus on reed failures. In this study, a reed in a force-balanced aviation relay was investigated, which comprised of internally oxidized Ag-Mg-Ni alloy. The fracture and microstructural investigation of the failed reed were conducted systematically, and the microhardness of the reed was also measured. The results indicated that the intergranular fracture occurred in the failed reed, and the failure of the reed was caused by severe Ni segregation. Abnormally large grains and remarkable difference in grain size for the core regions were observed in the failed reed, and the overall hardness of the failed reed was lower than the technical specification. The results indicated that Ni segregation led to inhomogeneous microstructure. In addition, secondary particles in the fracture surface were identified as Ni particles and oxides of Ni. Numerous nanoparticles were distributed in the grain boundaries, which led to intergranular brittle fracture of the reed. This study provides guidance on the evaluation of microstructure and failure analysis for Ag-Mg-Ni reeds.

We prepared a novel hemostatic material using chitosan (CS), alginate, and Bletilla striata, which showed good biocompatibility and hemostatic properties. Alginate-calcium porous microspheres (Alg) were prepared by emulsification/cross-linking methods, and Bletilla striata polysaccharide (Bsp) was extracted from the tubers by water extraction and alcohol precipitation. To improve the water absorption and accelerate the blood coagulation, Alg and Bsp were mixed with chitosan solution to form CS/Alg and CS/Alg/Bsp composite sponges by lyophilization. Based on SEM images, the microspheres exhibited good spherical shape, possessed many pores on the surface, and were well dispersed in the CS/Alg5 and CS/Alg10 composite sponges. The CS/Alg10 composite sponges showed higher water absorption and porosity. In addition, the cytotoxicity assay and hemostatic property of the CS/Alg and CS/Alg/Bsp composite sponges were tested by CCK-8 assay, in vitro blood clotting, red blood cell (RBC) adhesion, and rabbit ear artery bleeding. These ternary composite sponges could be used as potential novel hemostatic materials in surgical treatment.

Two-dimensional materials with a sheet structure have excellent optical, electrical and mechanical properties, and have attracted much attention in recent years, especially In

Many people have been affected by thrombotic events in several ways, all of which can give rise to the necrosis and death of tissues. Therefore, a sensitive way for detecting thrombus can enhance the efficiency of the diagnosis and the management of thrombosis. This study provided an originally activated platelet-targeted contrast agent for the detection of thrombosis. Utility Gd load apoferritin (Afn) nanocages, for MRI-enhancing contrast, were conjugated with a KGDS peptide, targeting integrin GPIIb-IIIa located on the membrane of human activated platelets. A transmission electron microscope (TEM) and dynamic light scattering (DLS) were used to examine the morphology of the prepared Gd-Afn-KGDS, which had the mean particle size about of 11.59 ± 0.37 nm with a narrow size distribution (the PDI was 0.21 ± 0.02). Hemolysis and cytotoxicity studies showed that the prepared Gd-Afn-KGDS had a great affinity for blood cells and vascular endothelial cells. Microscopy and in vitro MR imaging showed that the targeted nanoparticles bind to the blood clot and enhanced thrombus in the T1-weighted imaging, whereas in the control group, the non-targeted nanoparticles did not appear to have the same features. Thus, the evidence shows that the designed thrombus-specific, targeted T1-weighted contrast nanoparticles could potentially provide a benefit in the detection of thrombosis by MRI which could possibly be used in humans and might be useful for accurate thrombus therapy by entrapping thrombolytic drug inside the apoferritin nanocage.

Three-dimensional (3D) materials are widely used in optoelectronics, thermodynamics and ultrafast fiber lasers because of their excellent nonlinear optical properties. Silver sulfide (Ag2S) is a kind of 3D material with a unique tetragonal structure and large absorption coefficient. In this paper, a double-balance detection system is used to measure the saturation absorption intensity of Ag2S as 226.6 MW/cm2 and the modulation depth as 13.9%. In the ring fiber laser, Ag2S is used as a saturable absorber (SA) to obtain a stable dual-wavelength mode locking. The center wavelengths of the mode locking are 1536.9 and 1544.5 nm, and the corresponding 3-dB bandwidths are 1.3 and 1.5. nm. By adjusting the polarization controller (PC), a tuning process from two wavelengths to multiple wavelengths is realized, and the tunable width is 13.1 nm. This phenomenon is due to the combined effect of birefringence and nonlinear effects in the cavity. To our knowledge, this is the first report of a multiplexed fiber laser with Ag2S as a SA. The emergence of this result provides a valuable reference information for the multifunctional compact fiber laser, and the formed system can be applied in the fields of fiber sensing, telecommunications and optical communication.

Material flow uniformity in a die cavity is the key to extrude sound aluminum alloy radiators. However, it is generally difficult to control material flow due to their geometry features, such as complex cross section, multiple teeth, etc. In this work, for an irregular and multitooth aluminum alloy radiator, the initial extrusion die is firstly designed. Numerical simulation and experimental observation both show that the extruded radiator could not meet the size and shape requirements due to severe twist deformation in the cross section. Then, four different die modifications (resizing the porthole structure, chamfering the mandrel support, adding baffle plates, and adjusting bearing lengths) are taken to improve material flow uniformity during the extrusion process. Through a series of die modifications, the velocity difference in the cross section of the radiator is reduced from 34.9 mm/s with the initial extrusion die to 8.3 mm/s with the modified one. The standard deviation of the velocity field in the cross section decreases from 10.7 to 3.3 mm/s, and the velocity uniformity is improved greatly. With the modified extrusion die, a sound radiator is extruded with the desired size and geometry. Finally, the extrusion die modification rules are summarized for this kind of radiators.

Two-dimensional layered metal chalcogenides (LMCs) are widely used in battery anode materials, energy conversion, and semiconductor devices, because of their high energy storage characteristics, high thermoelectric characteristics, and large electron mobility. SnSe2 as a kind of LMC has strong nonlinear optical characteristics. However, its research on dissipative system dynamics as a saturable absorber has not been studied. In this work, we obtained SnSe2 nanosheets using lithium ion intercalation and we reported a passively mode-locked fiber laser with SnSe2 as a saturable absorber to achieve the dissipative soliton in a dissipative system. Due to the high third-order nonlinearity of SnSe2, the evolution of square wave pulses from 2 to 16 ns was obtained in a fiber ring cavity. Through adjusting the polarization state, the evolution phenomenon of soliton rain, the soliton rain phenomenon with a spectrum of dual-wavelengths, and a bound state harmonic phenomenon with a frequency of 313 MHz were obtained. Therefore, the strong nonlinear fiber laser based on SnSe2 provides a good platform for study the pulsation, explosion, rainfall and other phenomena.

A novel portable and cost-effective multi-wavelength smartphone colorimetric reader (MW-SCR) was designed for the quantitation of liquid colorimetric assays. Six light-emitting diodes (LEDs) with different wavelengths were assembled in a roulette fashion to form the light detection source. An ambient light sensor of smartphone was applied as the detector. Using this MW-SCR, we detected six common serum analytes, including alkaline phosphatase(ALP), potassium(K+), chloride(Cl−), alanine aminotransaminase(ALT), glycated serum protein(GSP), and albumin, to evaluate the feasibility and reliability of the MW-SCR. Strong linear regression (R2>0.99) analysis with a wide linear range and good limits of detection were found for this device, detection limits as low as 0.37 U/L, 0.0083 mmol/L, 0.78 mmol/L, 4.49 KarU, 0.023 mmol/L and 2.23 g/L for ALP, K+,Cl−, ALT, GSP and albumin, respectively, were achieved. It also had high repeatability that ranged from 0.20 to 0.61 % relative standard deviations (RSD), and the precision ranged of MW-SCR were from 0.26 to 1.17 % RSDs. Results demonstrated that our device showed remarkable stability, accuracy, and repeatability, presenting excellent consistency with a professional microplate reader. It can be redesigned for multiple indications, such as clinical biochemical analyses, food safety testing, environmental monitoring and so on, because it is open source, user friendly and easy manufacturing.

Two-dimensional materials with a sheet structure have excellent optical, electrical and mechanical properties, and have attracted much attention in recent years, especially In2Se3 (the N-type semiconductor compound), which has a rapid development in the fields of materials science and optical communication. In this paper, the nonlinear saturation absorption characteristics of In2Se3 are studied. The In2Se3 nanosheet dispersion can be used in ultrafast photonics applications. The nonlinear absorption is measured by power dependent method, and the modulation depth and saturation intensity are 3.8% and 246.6 MW cm-2, respectively. More importantly, In2Se3 is used as a saturable absorber (SA) in a passively mode-locked erbium-doped fiber laser. The proposed mode-locked fiber laser is demenstrated with a center wavelength of 1529.4 nm, a fundamental frequency of 5.9 MHz, a spectral width of 3.96 nm, a pulse width of 1.38 ps, and a signal-to-noise ratio of 55 dB. For the first time, harmonic mode-locking with a high-repetition rate of 431 MHz is achieved when the pump power is 360 mW corresponding to 73rd-order harmonic mode locking. It can be seen that In2Se3 is indeed a new excellent photonic material, which can be used in fiber optic communication, SAs photonics, laser material processing and light modulators.

To prospectively study the efficacy of different anti-adhesion agents for the prevention of tubal obstruction after recanalization, this trial was approved by our hospital ethics committee. Four hundred patients with fallopian tube obstruction were randomly assigned to four groups. The control group underwent recanalization alone, whereas the other groups were injected with chitosan, Dan-shen, or combined chitosan and Dan-shen after recanalization. The tubal patency rate in all four groups was recorded after 12 day, 3 months, and 12 months. The pregnancy rates were noted after 12 months. The recanalization rates after 1 day in the control, chitosan, Dan-shen, and combined chitosan and Dan-shen groups were 94.1, 97.1, 96.5, and 98.2%, respectively (p = 0.18, p > 0.05). The rates of tubal patency after 3 months were significantly higher in the combined chitosan and Dan-shen (96.5%), chitosan (88%), and Dan-shen (85.2%) groups compared with the control group (73.9%) (p = 0.0001, p

Bismuthene, a mono-elemental two-dimensional material with a novel kind of few-layer structure purely consisting of bismuth, has been predicted to have a prominent optical response and enhanced stability in theory. In this paper, few-layer bismuthene is employed as the saturable absorber. The mode-locker is fabricated by dropping bismuthene on a microfiber in a passively mode-locked, Er-doped fiber laser. The single pulse can be obtained at 122.1 mW, with 621.5 fs pulse duration at 1557.5 nm central wavelength, 10.35 nm spectral width and fundamental repetition of 22.74 MHz. Thanks to the outstanding nonlinear effect and semimetal of the bismuthene, dual-pulses, octonary-pulses and fourteen-pulses soliton molecules with tightly and loosely temporal separation can be achieved for the first time, to the best of our knowledge. The preceding indicates that bismuthene will have wide potential in many applications, such as optical fiber communications, optical logical gate, and laser materials processing, etc.

Allogeneic peripheral blood stem cell transplantation (allo-PBSCT) is a curative therapy for some types of hematological disorders. However, allo-PBSCT is commonly complicated with acute graft-versus-host disease (aGVHD), characterized by host tissues being attacked by the grafted donor lymphocytes due to disparities of human leukocyte antigen (HLA) between the donor and host. By contrast, cord blood transplantation (CBT) is typically associated with low-grade severity of aGVHD, but the underlying mechanisms remain unclear. Donor-derived CD4(+) alloreactive T cells (ATs) are of a specific lymphocyte subset, which can be activated by the recipient's HLA, and play a crucial role in the onset of aGVHD. In the present study, we aimed to explore the difference in the property of CD4(+) ATs between cord blood (CB) and adult peripheral blood (APB). We thus found that CB and APB CD4(+) ATs contained not only effector T cells (Teffs) that execute aGVHD, but also a distinct subset of FoxP3(+) regulatory T cells (Tregs) that may alleviate aGVHD. Importantly, CB CD4(+) ATs contained higher percentage of FoxP3(+) Tregs, compared to APB CD4(+) ATs (P < 0.001), while lower percentage of Teffs (Th1, Th2 and Th17 cells) was detected in CB CD4(+) ATs (P < 0.05, P < 0.001 and P < 0.05, respectively). Our findings suggest that FoxP3(+) Tregs in CB CD4(+) ATs may contribute to attenuating the severity of aGVHD observed after CBT.

Due to the excellent electrochemical characteristics, Sb4O5Cl2 has been potentially used in flame retardant, catalyst, and anode materials, etc. At the same time, it has broad application prospects in optics and optoelectronics because of its strong inoxidizability, high damage threshold and relatively high-photoelectric conversion efficiency. However, the application of Sb4O5Cl2 in ultra-fast photonics has not been reported so far. In this work, the structure characteristic and nonlinear optics property of Sb4O5Cl2 have been systematically studied. The result indicates saturation intensity and modulation depth are 402.5 MW/cm2 and 1.3%, which prove Sb4O5Cl2 could be utilized as a saturable absorber (SA) in ultrafast photonics. Especially, harmonic mode-locking with 850-fs pulse duration, 2.86-nm 3-dB bandwidth, 202.3-MHz maximum repetition rate in optical communication region is generated based on a tapered fiber incorporated with Sb4O5Cl2 for the first time to our knowledge. This work opens novel avenues toward optoelectronics device based on Sb4O5Cl2 in the fields of optical modulation, optical detection and optical communication, etc.

A promising technology for non-destructive fabricating microtapered long period fiber gratings (MT-LPFGs) is demonstrated by periodically slight tapering single-mode fiber. Owing to the optimized microtapering technique, high-quality LPFGs with dip attenuations of about 40 dB, insertion loss

The characteristics of air plasma are studied using laser-induced breakdown spectroscopy at room temperature in air at atmospheric pressure. The electron temperature of 20796 K is determined using the Boltzmann plot method with six ionic nitrogen lines at 444.703, 463.054, 500.515, 566.663, 594.165, and 648.205 nm. The electron number density inferred by measuring the Stark broadened profile of well-isolated Hα line (656.273 nm) is 1.83 ￡ 1017 cm?3. The hypotheses of the local thermodynamic equilibrium and optically thin plasma are verified based on the experimental results. These results are beneficial for better understanding of the terahertz (THz) wave generation in pulsed laser induced air plasma.

A long cavity passively mode locked fiber laser in the anomalous dispersion regime is reported. Nonlinear polarization rotation technique is employed to achieve the mode locking in our experiments. The output pulse from the fiber laser has the Gaussian profile spectrum and right angle trapezoid shape. Stable mode locking is achieved without using any dispersion-compensation components. The single pulse with an energy of 652 nJ and a repetition rate of 836 kHz at the pump power of approximately 500 mW is obtained and the duration of the output pulse increases linearly with the pump power. Different from the conventional low-energy soliton pulse, experimental results demonstrate that the passively mode locked fiber laser operating in the anomalous regime can also realize high energy pulse.

In this paper, we investigate the subcarrier allocation and power adjustment to maximize the sum data rate of the secondary users with limited interference to the primary users in OFDM-based cooperative cognitive networks. A fixed common relay is introduced to forward the data of the secondary users by adopting two-way amplify-and forward (AF) relay. By categorizing the subcarriers into 2 classes, the idle subcarriers and the busy subcarriers, we analyze the resource allocation problem for them and propose a resource allocation scheme which limits the power interferences caused to primary user and maximizes the sum data rate of the secondary users. The simulation results show that the proposed scheme can significantly increase the sum data rate.

When a debris flow joins a main river, it may block the river. The collapse of the block is often a sudden change that can be simplified into a phase transition. In this paper we study the problem on the model of percolation which is a second order phase transition. Rather than general random percolation model, we introduce a self-similar percolation model and develop it from two dimensions to three dimensions. Under this model, we conclude that a block made of grains (for example stone, sandy grains, clay grains, silt grains, etc.) with more different sizes has a better stability. Moreover, with the help of efflux theory, we explain why the joint on the other side of the block with the main river is easier to break than other places of the block.

This paper presents the design and implementation of a target tracking test bed based on wireless sensor network (WSN). The test bed is made up of a group of ultrasonic sensor nodes for ranging, a robot as mobile target for tracking and a laptop as base station for visualization. A new incremental optimization algorithm based on trilateration as well as a kind of changeable periodic scheduling scheme is applied in the test bed to pursue excellent tracking performance. The experimental result shows that the test bed can track a moving target effectively.

Aimed at that the quality of railway switch equipment is the key factor of railway-running security, fuzzy comprehensive appraisal method of switch equipment quality based on data-fusion of multi-sensor is presented, and testing platform of ZD6LH-S switch equipment is exploited which is controlled by PC and MCU. The problem of hierarchical determination about quality of switch equipment is solved, and the probability of equipment failure is degraded obviously.

Based on the non-relativistic theory and dipole approximation, we have developed a new program to study the interaction between a circularly polarized laser and hydrogen atoms. In this paper, we present our calculation of above-threshold ionization (ATI) rate based on the new code and compare the results with that of a pertubation theory calculation. The comparison shows that our non-perturbative calculations can produce ATI peak suppression.

A plasma generated by 1064?nm Nd:YAG laser irradiation of aluminum alloy in air at atmospheric pressure was studied spectroscopically. The electron density was inferred by measuring the Stark broadened line profile of Cu(I) 324.75?nm, while the electron temperature was determined using the Boltzmann plot method with ten neutral iron lines. Based on the results, local thermodynamic equilibrium was studied. Moreover, calibration curves were presented for samples containing Si, Fe, Cu, Mn, Mg, Ni, Zn and Ti, and the limit of detection of trace elements was calculated based on experimental results.