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In this paper, a compact filtering rat-race coupler implemented in low-temperature co-fired ceramic (LTCC) technology is presented. In order to reduce the dimensions, the schematic and the coupling topology of a planar filtering rat-race coupler are first studied and then simplified to fit the 3-D multilayer LTCC structure. An eight-line spatially symmetrical coupled structure is, therefore, proposed to obtain the required coupling topology between resonators. Thus, the filtering rat-race coupler can be constructed only by using four resonators, which is only half that of the planar one. Consequently, the size could be reduced substantially. For validation, a design example centered at 3.5 GHz is simulated, fabricated, and measured. All the measured results are in good agreement with the full-wave simulation results. Besides, the size of the circuit is only 3.8×4×2.1 mm3, which demonstrates that by employing the eight-line spatiallysymmetrical coupled structure, the proposed rat-race coupler obtains good performance and compact size.

Patch antennas with multiple feeds are proposed in this paper. The antennas consist of a traditional square patch and feeding probes that are set in a line orthogonal to the polarization direction. In addition to radiating EM energy just like the conventional antennas, the proposed multi-port antennas can also realize on-antenna power combining without power combiner. Thanks to this, high-line losses and large system size caused by extra power combiner can be avoided. Moreover, since the location and the number of ports have a limited effect on the antenna performances, flexible feeding strategies can be chosen in different applications. For demonstration, four patch antennas with a different number of ports (one port, two ports, three ports, and four ports) are designed at the center frequency of 1.5 GHz. Compared with the traditional one-port patch antenna, the proposed three multi-port patch antennas can achieve nearly the same antenna performance, including bandwidth, polarization, efficiency, and radiation pattern. Besides, one-port antenna and two-port antenna integrated with a two-way power amplifier are designed and measured, respectively. Then, they are compared to further prove the proposed power combining method in multi-port antennas.

A low-temperature co-fired ceramic (LTCC) filtering power divider with harmonic suppression is presented. It is composed of three resonators and one resistor. By using 3D technology, the two output resonators are symmetrically coupled to the input resonator to obtain the power splitting response. Each splitting path is composed of two resonators to achieve the filtering response. The resistor for isolation is located on the top layer and connected to the two output ports by vertical strips on the side walls. The broadside couplings between resonators produce required passband and stopband. A compact filtering power divider with the core size of 0.122λg × 0.1λg × 0.059λg is implemented. Good filtering, power splitting and isolation performance are achieved. What is more, the second harmonic is successfully rejected below 20 dB without any extra circuit. [ABSTRACT FROM AUTHOR]

A Ka-band dual-gate frequency doubler using 0.5 μm GaAs enhancement- mode pHEMT process is presented. The cascode circuit is equalised to the dual-gate frequency doubler and the relationship between bias and output matching is discussed to obtain the maximum output power and conversion efficiency. Since a pinch-off gate-to-source bias is driven at the input gate node, the frequency doubler consumes little DC power when injecting a low-power fundamental signal. Based on the analysis, the designed dual-gate doubler has a 3 dB bandwidth of 5.6 GHz, from 36 to 41.6 GHz. The fundamental suppressions are better than 15 dB. The measured maximum conversion gain is -0.9 dB at an injected power of 7 dBm. A high saturation output power is 7 dBm with a conversion efficiency of 14.3%. The measured results confirm the validity of the proposed analysis method. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of ovarian carcinoma cells on the differentiation, maturation, and function of the dendritic cells (DC)., Methods: Human epithelial ovarian carcinoma cells were isolated from specimens of ovarian carcinoma from 12 patients obtained during operation, and cultured. Peripheral blood samples were collected from these patients. DC were isolated and co-cultured with recombinant human tumor necrosis factor (TNF)-alpha to promote their maturation. Immunostaining and flow cytometry (FC) were used to detect the DC specific marker CD1a, maturation marker CD83, co-stimulating factors CD86 and human leucocyte antigen (HLA)-DR. FITC-labeled glucan was added and FC was used to detect the phagocytic function. T cells were co-cultured with immature and mature DC of different concentrations respectively for 96 h, 18 h before the end of culture 3H-TdR was added, liquid scintillation counter was used to measure the level of count per minute (cpm) Ovarian carcinoma cells and peripheral mononuclear cells were put into Transwell to contact each other directly or indirectly, TNF-alpha was add to promote the maturation, and then FC was used to detect the CD1a, CD83, CD86, and HLA-DR levels, and the glucan uptake level. ELISA was used to detect the levels of IL-12, IL-10, and interferon (IFN)-gamma, and Western blotting was used to detect the p-38 protein and phosphorylated p-38 protein in the supernatant., Results: After stimulation of TNF-alpha the expression; levels of CD1a, CD86, CD83, and HLA-DR of the DCs were remarkably increased. Immature DCs showed a strong ability at phagocytosis of glucan, and this ability was decreased by the stimulation of TNF-alpha. The proliferative function of mature DCs on allogenic T lymphocytes was significantly increased dose-dependently (P<0.05). Co-culture with ovarian carcinoma cells decreased the expression levels of CD1a, CD86, and HLA-DR, increased the expression level of CD83, and decreased the ability in up taking glucan by 43.05%. The proliferative function of the DC cultured in direct contact with ovarian carcinoma cells was decreased by 56.35%, and such inhibitory function of the DCs cultured not in direct contact with ovarian carcinoma cells was weaker, and the levels of CD1a, CD86, CD83, and HLA-DR expressed by the DC cultured not in direct contact with ovarian carcinoma cells was between those of the DC cultured in direct contact with ovarian carcinoma cells and those of the DC undergoing routine culture. The levels of IL-12 and phosphorylated p-38 protein were decreased in the supernatant of the DC co-cultured with ovarian carcinoma cells., Conclusion: Ovarian carcinoma cells suppress the differentiation of monocyte into DC, negatively regulates the phagocytotic and antaean managing functions of DC, thus the DC can not effectively stimulate the proliferation of T lymphocytes and inhibit the activity of cytotoxic T lymphocytes. That may be one of the underlying mechanisms of immune escape of tumor and immune tolerance of T lymphocytes.

Objective: To develop a new method to promote the differentiation of mesenchymal stem cells derived from human placenta (pMSC) to uterus smooth muscle cells (uSMC) in simulated uterus microenvironment., Methods: MSCs were isolated from human placenta, cultivated, and analyzed for their phenotype by flow cytometry. The multipotential differentiation of the pMSC was examined by chondrogenic, adipogenic, and osteogenetic induction. uSMC were isolated from uteri resected during operation and co-cultivated with the pMSC in a Transwell chamber simulating Two, 4, and 8 days later RT-PCR and Western blotting were used to detect the mRNA and protein expression of alpha-actin, calmodulin, and myosin heavy chains (MHC), the markers of smooth muscle differentiation at the early, middle, and late stages. On day 8 RT-PCR was used to detect the expression of estrogen receptor in these 2 groups of cells, then estrogen was used to stimulate these cells and the protein kinase C (PKC) activity was examined., Results: The pMSC could be induced into adipocytes, osteocytes, and chondrocytes respectively. After co-culture with uSMC, the morphology of the pMSC changed closely into that of the uSMC, and MHC was expressed in the pMSC. Estrogen receptor was positive in both groups of cells. The PKC activity increased, especially in the cell membrane, after stimulation of estrogen., Conclusion: The postpartum human placenta can be used as an important and novel source of multipotent stem cells for tissue engineering and genetic engineering. Placental MSC have the potential to differentiate into smooth muscle cells under the simulated uterus microenvironment in vitro.