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Using seawater, sea sand, and recycled bricks to make concrete for nearshore and marine engineering can save resources and protect the environment. Therefore, this article studies the mechanical degradation law and failure mechanism of recycled seawater and sea sand concrete (SSC) after seawater freeze–thaw (SFT) cycles. Using the replacement rate of recycled brick coarse aggregate as a variable, the mass loss rate, relative dynamic elastic modulus, compression and splitting tensile strength, and microstructure changes of specimens under different SFT cycles were tested, and a mechanical performance degradation model was established. The results indicate that the SFT failure of recycled brick coarse aggregate SSC results from the action of physical SFT and chemical crystallization. Friedel’s salts without cementitious properties and ettringite with expansive properties are generated inside the concrete due to the chloride and sulfate ions in the internal concrete and external seawater reacting with cement hydration products. The formation of harmful crystals leads to the loosening of the concrete, especially in the interface area between brick aggregates and cement. The calculated results of the mechanical model established in this article agree with the test results. The compression and splitting tensile strength decrease linearly with the increase in SFT cycles.

Abstract The present is a low‐profile, wide‐angle scanning, ultrawideband, tightly coupled dipole array that lacks a wide‐angle impedance matching layer and lossy materials. Impedance matching will deteriorate at the lower end of the operating bandwidth due to the influence of the ground plane. A well‐designed perforated balun is used to achieve better impedance matching. Moreover, parasitic metallic strips are attached to the dipole's side to add additional reactive components. According to the results of simulations, the impedance bandwidth of the array, which ranges from 0.67 to 2.83 GHz, and its wide‐angle scanning capability, which scans 75° in the E‐plane and 45° in the H‐plane, both achieve good performance when the voltage standing wave ratio is less than 3. The profile of the array is only 0.0581λlow above the ground plane, where λlow is the wavelength at the lowest operating frequency. The proposed array's simulated results are validated by fabricating and measuring an 8 × 8 prototype array.

In this study, the electrical characteristics of depletion-mode AlGaN/GaN high-electron-mobility transistors (HEMTs) with a SiNx gate dielectric were tested under hydrogen exposure conditions. The experimental results are as follows: (1) After hydrogen treatment at room temperature, the threshold voltage VTH of the original device was positively shifted from −16.98 V to −11.53 V, and the positive bias of threshold was 5.45 V. When the VDS was swept from 0 to 1 V with VGS of 0 V, the IDS was reduced by 25% from 9.45 A to 7.08 A. (2) Another group of original devices with identical electrical performance, after the same duration of hydrogen treatment at 100 °C, exhibited a reverse shift in threshold voltage with a negative threshold shift of −0.91 V. The output characteristics were enhanced, and the saturation leakage current was increased. (3) The C-V method and the low-frequency noise method were used to investigate the effect of hydrogen effect on the device interface trap and border trap, respectively. It was found that high-temperature hydrogen conditions can passivate the interface/border traps of SiNx/AlGaN, reducing the density of interface/border traps and mitigating the trap capture effect. However, in the room-temperature hydrogen experiment, the concentration of interface/border traps increased. The research findings in this paper provide valuable references for the design and application of depletion-mode AlGaN/GaN HEMT devices.

Cutting blasting has been widely used for tunnel excavation. The cutting forms significantly influence the blasting effect. This research focuses on the study of the relationship between cutting forms and blasting effects. Similarity theory is proposed for the experimental study of the rock blasting using small models. Then four experimental modes with different cutting forms are used to study the blasting effect due to the cutting forms. The cutting depth, borehole utilization rate, fragments volume, and average fragment size are analysed. The blasting effects with various cutting forms are compared. The influences of the borehole space and the blasting delay are discussed. It is concluded that the spiral cutting form can produce more fragments and is recommend for the small section tunnel excavation.

K. marxianus is a promising cell factory for producing heterologous proteins. Oxidative stresses were raised during overexpression of heterologous proteins, leading to the shift of the redox state. How to measure the redox state of live K. marxianus cells without perturbing their growth remains a big challenge. Here, a fluorescence lifetime imaging (FLIM)-based method was developed in live K. marxianus cells. During the early exponential growth, K. marxianus cells exhibited an increased mean fluorescence lifetime (τ-mean) of NAD(P)H compared with Saccharomyces cerevisiae cells, which was consistent with the preference for respiration in K. marxianus cells and that for fermentation in S. cerevisiae cells. Upon oxidative stresses induced by high temperature or H2O2, K. marxianus cells exhibited an increased τ-mean in company with decreased intracellular NAD(P)H/NAD(P)+, suggesting a correlation between an increased τ-mean and a more oxidized redox state. The relationship between τ-mean and the expression level of a heterologous protein was investigated. There was no difference between the τ-means of K. marxianus strains which were not producing a heterologous protein. The τ-mean of a strain yielding a high level of a heterologous protein was higher than that of a low-yielding strain. The results suggested the potential application of FLIM in the non-invasive screen of high-yielding cells.

Abstract Background Porcine Parvovirus (PPV) is a Parvovirinae virus that can cause embryonic and fetal loss and death and mummification in affected fetal pigs. Unlike conventional vaccines, virus-like particles (VLPs) inherit the natural structure of their authentic virions and highly immunostimulatory that can induce strong humoral immune and T cell responses with no risk of pathogenicity. The production of PPV VLPs is still a challenge based on traditional expression platforms due to their low yields and high culture costs. Kluyveromyces marxianus is a safe and fast-growing eukaryote that can get high biomass with low-cost cultures. In this study, we investigated the expression and downstream processes of PPV VLPs in K. marxianus, and the potential for effective stand-alone vaccines. Results After optimization according to the codon bias of K. marxianus, the VP2 protein from Kresse strain was highly expressed. In a 5 L fermentator, the yield of PPV VLPs reached 2.5 g/L, quantified by HPLC, using a defined mineral medium after 48 h fermentation. Two strategies were established to purify intracellular PPV VLPs: (i) Using the cation exchange chromatography coupled with Sephacryl® S-500 HR chromatography to purify VLPs from the supernatants of pH adjusted cell lysates. (ii) Using anion exchange chromatography followed by cross-flow diafiltration to recover the VLPs precipitated in pH adjusted cell lysates. The purity of PPV VLPs reached about 95%, and total recovery was more than 60%. Vaccination of mice with the purified PPV VLPs induced high titers of specific IgG antibodies in sera, and showed hemagglutination inhibitions on both swine and guinea pig erythrocytes. Spleen lymphocyte proliferation and cytokines detection suggested the PPV VLPs produced by K. marxianus provoked the cellular immune and humoral immunity responses in mice. Conclusions This is the highest production of recombinant PPV VLPs achieved to date. The superiorities, Generally Recognized As Safe (GRAS), high production, short lead time, and low cost, make K. marxianus a greatly competitive platform for bioproduction of PPV VLPs vaccine.

Since the probe coupling for cavity filters is unsuitable for ceramic-filled cavity filters, a novel capacitive cross-coupling structure is proposed to improve stopband suppression by introducing transmission zeros. This structure is implemented by first etching a coupling window on the silver-plated layer on the ceramic surface between two resonant cavities and then placing an isolated metal strip in the window. This structure enjoys high design freedom. Thus, the coupling coefficient between the two cavities is readily adjusted. Moreover, the structure has the advantages of a compact size and simple fabrication and tuning processes. For validation, a ten-pole ceramic-filled cavity filter for 5G applications is designed and evaluated. The proposed cross-coupling technology is used to introduce a pair of symmetrical transmission zeros at the band skirts to increase the frequency selectivity. The measured results are consistent with the simulated ones.

Complementary sources concept and half-mode/quarter-mode substrate integrated waveguide (HMSIW/QMSIW) technology are introduced in this paper to improve the back-radiation suppression and bandwidth of microstrip patch antennas (MPAs). The HMSIW cavity as the feeding structure brings an additional resonant frequency to the inherent resonant mode of typical MPAs, which efficiently extends the bandwidth of the MPAs. In addition, while stimulating the MPA mode, the HMSIW cavity drives a monopole by slightly breaking the shorting wall of the HMSIW cavity and loading a printed monopole. The loaded monopole and the equivalent magnetic currents of the MPA construct an orthogonal complementary source model that indicates back radiation suppression. A differential feeding scheme is also employed to enhance the radiation performance. The dual-polarized model, achieved by replacing the HMSIW cavity with QMSIW cavities, is also addressed and even fabricated and tested. The measured results show a differential impedance bandwidth of 15.4% from 1.91 GHz to 2.23 GHz with a differential port-to-port isolation of 38 dB. In the operating band, the average gain is 7.5 dBi, and the front-to-back ratio (FBR) is over 18 dB with a maximum value of 34 dB.

A wristwatch-style wearable dielectric resonator antenna (DRA) is proposed for the 2.45-GHz ISM band and sub-6 GHz 5G NR bands around 2.5 GHz, such as the commercial band for China Mobile Communications Corporation. The antenna is designed for applications on forearms and ankles. Practical concerns, including the aligning method, platform size, specific absorption rate, and user effects are investigated. Coplanar feeding structure is applied for alignment and isolation. Analysis of the watchband-like substrate is highlighted to avoid performance degradation. Given that platform configurations are not discretionary in actual devices, parasitic loading is introduced to attain desirable substrate effects and suppress unwanted ones. The user-device interplay is studied in light of actual application scenarios. The specific absorption rate is calculated through multilayer biological tissue models. Meanwhile, radiation variation caused by users is estimated based on human phantom models and measurements.

In this paper, a novel circularly polarized (CP) antenna that achieves high gain by maximizing the radiation aperture utilization is proposed for vehicle applications. The realization of increasing the radiation aperture is based on the application environment, making full utilization of the vehicle roof, a large metal reflector beneath the antenna, which is indispensable in the vehicle application. Developed from the structure of typical microstrip patch antenna, the design extends the radiation patch to cover the side of the dielectric substrate, which increases the size of the radiating patch without increasing the antenna's outline size. To make CP antennas more suitable for special working environments with large reflecting surface, a sequential rotation feeding structure with 90° progressive phase difference is uniquely designed based on the active port impedance of the four-ended radiation structure. This co-design method introducing the active port impedance of a multi-port radiator into the design of feeding network as the loads can effectively guarantee the CP performance of the antenna, and can greatly simplify the optimization work in the subsequent stage. Based on this design idea, a prototype working at 1.48 GHz with a 50-MHz bandwidth is designed for vehicle satellite broadcasting application. Experimental results show that the antenna achieves a high CP gain greater than 7 dBic with a compact size of $50 \times 50 \times 10\,\,mm^{3}$ ($0.247\lambda _{0} \times 0.247\lambda _{0} \times 0.05\lambda _{0}$ , $\lambda _{0} $ is the wavelength of working frequency in free space).

The characteristic modes (CMs) analysis can give physical insights into the intrinsic mechanisms of radiating structures. To obtain the CMs of composite metallic-dielectric objects is a very challenging task. Existing formulations encounter some problems in calculating the CMs of multiple and multi-layer composite structures. In this paper, we present two new surface integral equation (SIE) formulations for the calculation of CMs of composite metallic-dielectric objects. Employing the contact-region modeling (CRM) technique and the inherent dependent relationships between various kinds of equivalent sources, we propose two new SIE-based CM formulations wherein the electric or magnetic currents on the surfaces of dielectric regions are alternatively involved to suppress spurious modes. Compared to the existing formulations, the proposed formulations are easier to be extended to multiple and multi-layer composite structures. Numerical results of five representative structures are presented to validate the accuracy of the proposed formulations.

Theory of characteristic modes (TCM) can provide physical insight into the radiation mechanism of arbitrarily-shaped electromagnetic objects. However, how to compute the characteristic modes (CMs) of different structures is still an open problem. Even for the calculation of CMs of an isolated dielectric body, there are eleven integral equation (IE)-based formulations which result in different modal solutions. Such kind of non-uniqueness of solutions makes CMs community confused. One of the objectives of this paper is to outline the differences among all existing IE-based formulations for the CMs of dielectric bodies. The existing formulations are briefly reviewed and carefully compared. We present a procedure to implement the different formulations in a unified manner. Then, we make a complete comparison of the numerical results of existing methods for a dielectric cylinder, which also serves as cross-validation for these approaches. We hope that this paper will help researchers understand the calculation of CMs of dielectric bodies and explore the computation methods of CMs for more complex objects.

In this paper, the feasibility of using the half-mode/quarter-mode of a substrate integrated waveguide (HMSIW/QMSIW) cavity to feed microstrip patch antennas (MPAs) is explored; based on this, a circularly polarized (CP) MPA fed by the sequential rotation QMSIW cavities is proposed. For more compact and higher integration, the active circuits are packaged inside the microstrip patch antenna. Correspondingly, the QMSIW cavities have also been chamfered, and slots are designed on the upper surface to reduce the influence of the chamfer operation. The SIW cavities introduced an additional resonant mode, which can essentially enhance the bandwidth of the MPAs. The fabricated prototype shows a bandwidth of about 9% (1.42GHz - 1.55GHz) with an average CP gain of 7 dBic. In addition, the adoption of HMSIW/QMSIW cavity excitation allows the microstrip patch antenna to retain a seamless ground plane as well, which facilitates further integration with other components of the communication system by printed circuit board lamination technology.

Compact arc-shaped conformal dielectric resonator antennas (DRAs) loaded by metal plates and high-dielectric-constant (HiK) patches are investigated. Their miniaturizing principles are analyzed from different aspects. Closed-form expressions are derived to characterize the function of the conformal ground in size reduction. Difference between the conventional flat ground and conformal one is discussed. As to lateral metal loading, its influence on radiation patterns are utilized to acquire additional function. Next, to replace the metallic structure, HiK patches are used as perfect electric conductor (PEC) walls. Their working mechanisms are analyzed through the electromagnetic theory in layered media, and waveguide-based simulation methods. As validation, a dielectric-loaded arc DRA is proposed. By working like a PEC, the thin dielectric patch reduces the DRA size to one half. Similar characteristics are observed between the dielectric- and metal-loaded antennas. Finally, a bare DRA and a miniaturized one are fabricated and measured. This research expands the miniaturizing theory of conformal arc DRAs.

Ground effects on arc-shaped conformal dielectric resonator antennas (DRAs) working in the TE11δz mode are investigated and utilized to attain various radiation performances. Manipulation of directivity patterns are achieved with the help of the three-dimensional curved metal ground. The backlobe, beamwidth, broadside gain, backscattering, and cross-polarization level of the antenna are all readily controllable. The geometric theory of diffraction is applied to provide an intuitional explanation for the radiation changes. Detailed analysis is then conducted from the perspective of ground current. It is found that the current distribution is affected by configurations of both the arc DRA and ground plane. Based on this, analytical methods are developed to calculate the ground effects exclusively for conformal arc-shaped DRAs. Next, the design theory of arc DRAs with curved ground is proposed. To demonstrate it, two conformal DRAs owning directional and wide beams, respectively, are designed as paradigms. At last, a prototype is fabricated and measured for validation.

The conventional monopulse comparator, which commonly consists of a power divider, a standard 3dB-coupler and a 90-degree phase shifter, occupies a significantly large area of the antenna aperture. This results in a low efficiency. In order to improve the antenna's aperture efficiency and keep a planar single-layer structure simultaneously, a substrate integrated waveguide (SIW) slots array monopulse antenna excited only by a square dual-mode (TE120 and TE210) SIW resonator is proposed, fabricated and measured in this communication. The sum and difference beams are obtained when the feeding cavity operates at two high-order modes, respectively. The needless of complex feeding network reduces the antenna's structure complexity and improves its aperture efficiency. The aperture efficiency of the antenna can reach 42%. Besides, the sum and difference ports have good isolation due to the orthogonality between the two modes. The proposed antenna obtains a 100 MHz impedance bandwidth, determined by the reflection coefficient less than -10 dB. The measured gain of the sum pattern is 11.9 dBi at 10 GHz, while the null depth of the difference pattern is lower than -27 dB.

Saline soil in Western China contains high concentrations of chloride ions, sulfate ions, and other corrosive ions, and the performance of concrete will substantially deteriorate from exposure to this environment. Therefore, it is of great significance to study and predict the concrete compressive strength in saline soil environments. In this paper, the effects of corrosion on concrete were analyzed from the aspects of surface damage, damage depth, and X-ray diffraction (XRD) of the corrosion products. The effects of corrosion were quantified by damage depth and corrosion depth. Then, considering the corrosion effects combined with Fick’s diffusion law, a time-dependent model of concrete compressive strength and a time-dependent model of damage depth were established. The results show that the deterioration of concrete gradually developed from the surface to the interior, and that the interface of the concrete specimen was equivalent to three parts: a failure zone, a filling zone, and an undisturbed zone. The results also showed that the time-varying model of concrete compressive strength proposed by the author was fully applicable, with an error of less than five percent. The service life of concrete predicted by the damage depth was found to be about 253 months (21.1 years), and the service life predicted by the time-varying compressive strength model was about 187 months (15.6 years). Both prediction results were far less than the normal concrete service life of 50 years. In addition, the long-term compressive strength of the corroded concrete was about 90% of that of the noncorroded concrete, which did not deteriorate with the corrosion time.

Bolted connections are widely used in multiple engineering fields including aerospace and mechanical engineering due to their numerous advantages like the ability to bear relatively heavy loads, low costs, easy installation, and implementation. Bolt looseness may lead to costly disasters in industries and some cases of injuries. A new method for bolt looseness detection based on average autocorrelation function is proposed. It does not usually directly extract the looseness damage feature from the original response signal to detect the bolt looseness, but it uses the average autocorrelation function value at time lag T = 0 of the vibration pixel displacement signal to establish the looseness damage index. In terms of structural arrangement of this paper, firstly, the theoretical background of the proposed method is given. Then, an experimental system for bolt looseness detection based on computer vision is designed, and a verification experiment is carried out with the bolted connection plate as the experimental object. The results show that the proposed method can effectively obtain the location of the looseness damage of the bolted connection plate, which provides a new technical reference for the online monitoring of the looseness damage of bolted connection plate.

In the process of tunnel excavation, large charge wedge cutting blasting is widely used to improve the effect of cut blasting and speed up the excavation rate, which is tantamount to increasing the construction cost. In order to save economic cost and improve cutting blasting effect, wedge cutting models with five different cutting angles were experimented and studied by using concrete materials on the basis of similarity theory analysis. The relationships among cutting depth, blasting volume, blasting fragment, and cutting angle are studied and deduced by the dimensional analysis method. The polynomial fitting of cutting depth, blasting volume, blasting fragment, and cutting angle is carried out according to the experimental data, and the corresponding fitting formula is obtained. The optimum cutting depth, hole utilization rate, blasting volume, and blasting fragment were obtained when the wedge cutting angle was 67° under the same charge. The values were 1.665 × 10−1 m, 92.5%, 8.390 × 10−3 m3, and 49.07 mm, respectively. With the use of TC4850N type blasting vibration meter, the blasting vibrations on the wedge in four directions are tested and analyzed. The results show that when wedge cutting inclination is 65 degrees, the peak vibration velocity is the minimum and the vibration intensity of the wedge cutting inclined side is generally smaller than that of the vertical side. Considering the cutting depth, blasting volume, blasting fragment, blasting vibration hazard, drilling error, tunneling construction cost, and other factors, the 65°∼69° wedge cutting blasting in engineering practice can improve the blasting tunneling rate and increase economic benefits. The experimental results show that the blasting tunneling rate is increased and the economic benefit is increased with the minimum construction tunneling cost, which has certain engineering significance.

In this paper, we propose a low-profile ultra-wideband (UWB) antenna for wireless body area networks. The proposed antenna is low-weight and easy to produce by printed circuit board manufacturing. Optimized shape of the radiation patch and shorted top-loading patches are introduced to broaden the bandwidth and reduce the profile of the antenna. The height of the antenna is 0.05λ0, where λ0 is the free-space wavelength at the lowest operating frequency. The simulated and measured results show that an enhanced impedance bandwidth of about 162% in the range of 2.5 to 24 GHz (S11

Infectious bursal disease (IBD), caused by the infectious bursal disease virus (IBDV), is a highly contagious and immunosuppressive disease in chickens worldwide. The novel variant IBDV (nvIBDV) has been emerging in Chinese chicken farms since 2017, but there are no available vaccines that can provide effective protection. Herein, the capsid protein VP2 from nvIBDV strain FJ-18 was expressed in Kluyveromyces marxianus with the aim to produce nvIBDV subviral particles (SVPs). Two recombinant strains constructed for expression of nvIBDV VP2 (nvVP2) and His-tagged VP2 (nvHVP2) formed two types of nvIBDV subviral particles (SVPs), namely nvVP2-SVPs and nvHVP2-SVPs. TEM scans showed that both SVPs were about 25 nm in diameter, but there was a large portion of nvVP2-SVPs showing non-spherical particles. Molecular dynamics simulations indicate that an N-terminal His tag strengthened the interaction of the nvHVP2 monomer and contributed to the assembly of SVPs. Vaccination of chicks with the nvHVP2-SVPs provided 100% protection against novel variant IBDV infection when challenged with the FJ-18 strain, as well as the classical strain BC6/85. By contrast, vaccination with the nvVP2-SVPs only provided 60% protection against their parent FJ-18 strain, suggesting that the stable conformation of subviral particles posed a great impact on their protective efficacy. Our results showed that the nvHVP2-SVPs produced by the recombinant K. marxianus strain is an ideal vaccine candidate for IBDV eradication.

A miniaturized ultra-wideband Vivaldi antenna is proposed in this paper. Optimized slots are inserted in the radiation patches to obtain a low frequency resonance. Two substrates with radiation patches are put back to back, forming a double-layered structure. Thus, the transverse E-field of the doublelayered structure is significantly reduced due to this symmetric treatment, which gives rise to very low cross polarization. The measured results show that an enhanced impedance bandwidth of approximately 126% in the range of 2.5-11 GHz (S11 0 x 0.26λ0 x 0.02λ0, where λ0 is the freespace wavelength at the lowest operating frequency. Furthermore, the cross polarization is -40 dB over the bandwidth. The time-domain behavior of the Vivaldi antenna is tested, and the results show a low cross polarization in the time domain and admirable time-domain responses.

In this paper, a wide-band low cross polarization antenna with a structure of microstrip line coupling to slot line as the balun is proposed. The radiation part of the antenna is fed by two pairs of parallel transmission line via a transition from a slot line which is coupled by a microstrip line. Because it is fed by parallel transmission lines, which is balanced-fed structure, the antenna can achieve an improved low cross-polarization performance. The height of the antenna is 0.146λ0 (λ0 is the wavelength of lowest frequency). The prototype antenna demonstrates a measured impedance bandwidth of 93.5% (2.7-7.44 GHz), a 3-dB-gain bandwidth of 77% (2.7-6.1 GHz), and a maximum gain of 10.5 dBi at 4.5 GHz.

A wideband dual-polarized planar antenna is designed and analyzed by using the theory of characteristic modes (TCM). The eigenvalue, eigencurrent, characteristic pattern, and modal weighting coefficient are analyzed to bring physical insight to this kind of antenna. The results demonstrate that there are two modes resonant in the operating band for each polarization, which have been combined to form a wider frequency band. A bandwidth of 60.2% (1.72–3.2 GHz) for VSWR < 1.5 with high isolation of 32 dB is achieved simultaneously. The size of the radiator structure is 0.33λ0 × 0.33λ0 × 0.22λ0 (λ0 refers to the center operating frequency).

A single-point-fed circularly polarized (CP) rectangular dielectric resonator antenna (DRA) with wide CP bandwidth is presented. By using TE111 and TE113 modes of the rectangular DRA, a wideband CP performance is achieved. The coupling slot of the antenna contains a resistor loaded monofilar-spiral-slot and four linear slots. Design concept of the proposed antenna is demonstrated by simulations, and parameter studies are carried out. Prototype of the proposed antenna was fabricated and measured. Good agreement between the simulation and measurement is obtained. The measured impedance bandwidth (|S11|

A rapid, simple and sensitive ultra-performance liquid chromatography-electrospray-ionization-tandem mass spectrometry (UPLC-ESI-MS/MS) method was developed and validated for the simultaneous determination of aesculin, aesculetin, fraxetin, fraxin and polydatin in beagle dog plasma for the first time. Plasma samples were pretreated by protein precipitation with methanol. Chromatographic separation was performed on an Acquity UPLC HSS T3 C18 column (2.1 mm × 100 mm, 1.8 μm) with gradient elution at a flow rate of 0.4 mL/min, using a mobile phase consisting of 0.1% formic acid (A) and acetonitrile (B). The analytes and IS were detected by multiple reaction monitoring (MRM) via negative ion mode with ion transitions of m/z 339.1–m/z 176.8 for aesculin, m/z 176.8–m/z 88.9 for aesculetin, m/z 206.8–m/z 192.1 for fraxetin, m/z 369.1–m/z 206.9 for fraxin, m/z 389.1–m/z 227.0 for polydatin and m/z 415.2–m/z 295.1 for puerarin. This method was validated according to the FDA guidelines and the results met the requirements of analysis. The calibration curves of analytes were linear with correlation coefficients more than 0.9980. The intra- and inter-day precisions were less than 15% and the accuracy was within ±15%. The maximum plasma concentration (Cmax) of aesculin, aesculetin, fraxetin, fraxin and polydatin was 46.75 ± 7.46, 209.9 ± 57.65, 369.7 ± 48.87, 67.04 ± 12.09 and 47.14 ± 12.04 ng/mL, respectively. The time to reach the maximum plasma concentration (Tmax) was 1.32 ± 0.38 h for aesculin, 1.03 ± 0.27 h for aesculetin, 0.94 ± 0.23 h for fraxetin, 0.83 ± 0.18 h for fraxin and 1.15 ± 0.15 h for polydatin. The results indicated that the absorption of aesculin might be slow in beagle dog plasma. This method was successfully applied for pharmacokinetics in beagle dog plasma after oral administration of the extracts of Ledum palustre L. at a dosage of 0.27 g/kg.

A novel planar inverted-F antenna (PIFA) with dual-shorting points is proposed for multiband mobile handsets. The antenna comprises a meandered strip, a feeding point, two shorting points, and a slotted ground plane. For bandwidth enhancement of DCS/PCS/UMTS/WLAN 11.b/LTE2300/2500 and IMT-Advanced (International Mobile Telecommunications-Advanced), the antenna applies a dual-shorting points design, which generates a multimode between 1707 and 2815 MHz. The proposed antenna has good impedance matching characteristics for GSM (824–960 MHz)/DCS (1710–1880 MHz)/PCS (1850–1990 MHz)/UMTS (1920–2170 MHz)/LTE (2300–2400 MHz, 2500–2690 MHz)/WLAN 11.b (2400–2480 MHz) and IMT-A (4200–4800 MHz). The measured radiation efficiencies of the proposed antenna were all higher than 60% in GSM850/900, DCS/PCS, UMTS, LTE2300/2500, and WLAN 802.11 b, and it is up to 86% in IMT-A.