A new approach to achieve beam steering at a fixed frequency by adjusting the amount of the filled dielectric material is presented. It is realized based on a standard waveguide with longitudinally slotted on the broad wall, where a layered structure is designed. By selectively filling the proposed layered structure with the low-loss transform oil $(\epsilon_{r}=2.2)$ , the effective permittivity of the medium inside the waveguide is altered, which consequently leads to the the beam steering of the waveguide antenna. To validate this concept, a six-layer container and a non-resonant 20-slot waveguide slot array operating at 13 GHz are designed. The simulation results show that the main beam scans from $-47^{\mathrm{o}}$ to $-6^{\mathrm{o}}$ and the gain varies from 11.88 $\text{dBi}$ to 14.52 $\text{dBi}$ , when the container is gradually filled with transform oil from empty to full. The results demonstrate that the proposed structure can effectively achieve beam-steering at the fixed frequency.
Shenxiang Suhe Pill (SXSHP) is a traditional Chinese medicine (TCM) widely used to treat coronary heart disease. The present study aims to investigate the effect of SXSHP on posterior circulation ischemic (PCI) vertigo.One hundred and twenty patients with PCI vertigo were randomly divided into the control, low-dose, and high-dose groups with 40 patients in each group. The control group was treated with basic Western medicine. The low-dose and high-dose groups were treated with 0.7 g SXSHP once a day in the morning and twice a day in the morning and evening, respectively. The assessments were performed on days 14 and 28. The traditional Chinese medicine symptom score, average blood flow velocity of vertebral artery and basilar artery, blood viscosity, blood lipids, serum C-reactive protein level (CRP), blood routine test, and liver and kidney function were compared before and after treatment among the 3 groups.In the evaluation of the traditional Chinese medicine symptom score, both low-dose and high-dose SXSHP treatments showed higher efficacy than the control group (P = .013). The average blood flow velocity of vertebral artery and basilar artery in the 3 groups showed an upward trend from baseline (P < .05). The blood viscosity and levels of fibrinogen, hematocrit, and CRP in the 3 groups showed a downward trend from baseline level (P < .05). The levels of total cholesterol, triglycerides, low-density lipoprotein, and CRP in the low-dose group and high-dose group were lower than those in the control group on day 28 (P < .05). There were no significant differences in the routine blood test and liver and kidney function between the low-dose and high-dose groups compared with the baseline values (P > .05).SXSHP effectively improved PCI vertigo by inhibiting blood viscosity, regulating blood lipid levels, anti-inflammation, and improving cerebrovascular blood flow without affecting liver and kidney functions.
Background: Tendon-repair techniques have evolved to increase the construct strength of the repair site in order to permit early active range of motion without tendon gap or rupture. The present study evaluated the hypothesis that the injection of botulinum neurotoxin type-A (BoNT-A) into the gastrocnemius muscle will reduce the active force production of that muscle below the force required to rupture the associated, repaired Achilles tendon. Methods: Seventy-nine rat Achilles tendons were surgically bisected and were repaired with use of a two-strand core suture with a running epitenon repair. After the repair, the animals were treated with unilateral intramuscular (gastrocnemius) injections of either BoNT-A (6 U/kg body weight) (thirty-seven rats) or saline solution (forty-two rats). Operatively treated ankles were fixed in the neutral position with a percutaneous pin for the first two days after surgery. Unrestricted ankle motion and weight-bearing were allowed after the second postoperative day. An assessment of gap formation or rupture at the repair site, electrophysiologic measurements of force applied to the tendon, and an assessment of the strength of the repaired tendon were performed. Results: Intramuscular BoNT-A injections produced a significant, reversible reduction in active muscle force (p < 0.007). Twitch and tetanus contractions decreased to approximately 25% of the values for the control side within one week, remained at <50% of the values for the control side at one month, and returned to normal levels by six months. The tetanic force capability of the muscles that had been injected with BoNT-A was fivefold to tenfold less than the force required to rupture the associated Achilles tendon for as long as four weeks after tendon repair. The spontaneous Achilles tendon rupture rate of repaired tendons in the BoNT-A group was three times lower than that in the saline solution group at one week, and the tendon rupture force was significantly higher in the BoNT-A group between one and three weeks after repair (p < 0.007). There was no significant difference in tendon rupture force between the two groups after three weeks. Conclusions: Intramuscular gastrocnemius BoNT-A injections were associated with a significant reduction in force-generating potential, such that the muscle was incapable of actively producing enough force to rupture the repaired Achilles tendon in this rat model of tendon repair. Clinical Relevance: The temporary decrease of active muscle-tendon forces produced by intramuscular BoNT-A injections has the potential to allow early active motion, to provide a pharmacologically mediated aid (bioprotection) to improve patient compliance with rehabilitation, and to enhance patient outcomes.
The advancement in nano-technology and the increasing demands for healthcare technologies are expediting the progressing of In-vivo Wireless Nanosensor Networks (iWNSN)[1]. With the development of miniature plasmonic signal sources, an tenna and detectors, wireless communication among intra-body nano-devices will be expectedly enabled at both terahertz [2] and optical frequencies[3]. Due to the limited energy and capabilities of nano-devices, it is generally believed that the information could be transmitted in femtosecond-long pulses [4]. Apart from the electromagnetic properties of the biological tissues at the operation band, the pulse shape also has a great effect on the communication performance. Since the path loss sharply increases with the rise of the frequency, thus, it is recommended that the lower band of the THz and optical freq uencies should be adopted. We evaluate the channel capacity for 0.1 ∼ 1THz and received power for 400∼450THz communication inside the layered skin. The transmitted signal power is $1\mu \mathrm{W}$ , the duration of the Gaussian pulse is 100 femtosecond, and the standard deviation equals to 10fs. The channel capacity of THz communication inside the skin can be around 5 Gbps when the propagating distance is 1 mm. While in the optical communication, the received signal power at 1mm for the considered optical communication is around −92dBm. The obtained results comparatively quantize the potential of the THz and optical communication inside the human body.
A model of large core and multimode photonic crystal fiber (PCF) with sealed air holes at its end face is proposed for the first time. The model indicates that this PCF can be replaced by another equivalent fiber with complete holes at a new end-face position. Instead of a segment of glass rod between the old and new end faces, light rays travel in a virtual medium with the loss rating of pure glass but the refractive index of the immersion medium. For a two-fiber structure, this segment of pure glass has the capability of enhancing the light collection efficiency, which is investigated using a specifically designed fiber probe and fluorescent samples with different concentrations.
Recognition of road surface conditions should always be at the forefront of intelligent transportation systems for the enhancement of transportation safety and efficiency. When road surfaces are covered by ice or snow, accident rate would increase due to the reduction of road surface roughness and also friction between tire and road. High-resolution recognition of natural and manmade surfaces has been proved to be achievable by employing radars operating at low-terahertz frequencies. In this work, we present theoretical investigations on surface condition recognition of an icy road by employing low-terahertz frequencies. A theoretical model combining integral equation method (IEM), radiative transfer equation (RTE) and Rayleigh scattering theory is developed. Good agreement between the calculation results and measured data confirms the applicability of low-terahertz frequencies for the evaluation of icy road surface in winter. The influence of carrier frequency, ambient temperature, impurities inside the ice layer and frozen soil surface conditions on the efficiency of this method is presented and discussed.
This work describes the diffuse scattering response of a terahertz data stream on metallic rough surfaces. The measurements are performed using a wireless link with carrier frequencies operating from 100-400 GHz. We discuss the implications of surface roughness for non-line-of-sight (NLOS) paths in non-specular directions.
Based on the previously proposed concept of a lab on a fiber (LOF) and an LOF-based platform for detecting trace vapors of TNT explosives, in this paper, we study the compatibility of the LOF device with a preconcentration unit. We report the detail investigation of factors that crucially affect the overall performance of this LOF platform. From a theoretical perspective, we investigate the efficiency of a light source formed at the fiber tip on sensory film excitation. Experimentally, we demonstrate the much faster response time of the LOF over a sensory film on a bulky planar glass substrate. We also evaluate the following factors that significantly impact the sensitivity of the instrumentation system: 1) the proper bond between the sensory film and the fiber surface; 2) the concentration of polymer solution for thin-film formation; and 3) the degradation of thin film in the presence of ambient light and the oxygen content in the air.
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