19 research outputs found
Enabling Technologies for Broadband In-Band On-Channel Digital Radio
Thesis (Ph.D.)--University of Washington, 2012Due to inadequate spectrum resources and increasing demands for high quality multimedia services, traditional analog broadcasting is being migrated into digital radio around the world. This dissertation focuses on the development of several innovative broadcasting technologies and the design of so-called Broadband Digital Radio (BDR) system, which is suitable for digital audio and data broadcasting in FM and AM channels. The new broadcasting system synergistically integrates frequency hopping, LDPC coding, hierarchical modulation and band aggregation techniques to increase the data rate, improve spectrum efficiency, and at the same time, provide the spectrum flexibility necessary in high quality audio and multimedia services. One of the key features in the BDR is the powerful hierarchical modulation scheme that offers significant performance enhancement over existing schemes (e.g., DVB-T). In this dissertation, we present a novel decoding algorithm for the hierarchical modulation. Unlike the traditional hierarchical demodulation approaches which suffer from serious inter-layer interference (ILI), the proposed method exploits the structure information of the secondary layer to mitigate the ILI impairment, thereby offers significant gains in reception performance. For the digital network, frequency planning is needed as in other digital broadcasting signals. Most importantly, the single frequency network (SFN) architecture will be used in the BDR deployment. The hierarchical modulation technique is also adopted in the SFN to provide both global and local information. Accordingly we develop a low-complexity successive interference cancellation (SIC) algorithm to ILI and inter-cell interference (ICI) in the HM based SFN. The performance evaluation and decoding complexity comparisons indicate that the proposed structured SIC approach offers a good performance-complexity trade-off, especially for the HM-based SFN scenarios. Finally, a BDR prototype has been developed on a personal computer (PC) based software defined radio (SDR) platform. Numerical results and initial laboratory tests demonstrate significant performance advantages of the new design over existing systems such as the Digital Radio
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Particle-attached microorganism oxidation of ammonia in a hypereutrophic urban river.
To elucidate the importance and mechanisms of particle-attached microorganisms on ammonia oxidation, we conducted a controlled simulation experiment with samples collected from the Shunao River, an ammonia-rich hypereutrophic urban river in eastern China. The effects of particle concentration, ammonia concentration, organic carbon source and concentration, dissolved oxygen concentration, and pH were investigated on ammonia transformation rate (ammonia removal rate and NO2 -  + NO3 - accumulation rate) and abundance of particle-attached ammonia-oxidizing bacteria (AOB) and archaea (AOA). All these factors significantly influenced ammonia transformation rates. Our results provided direct evidence that microorganisms attached on riverine suspended particles were associated with ammonia oxidation. Sequencing revealed that the AOA genus Nitrososphaera, and the AOB genus Nitrosomonas were the most dominant in particle-attached ammonia-oxidizing microbial communities. Further analysis showed that AOB communities had higher species richness and diversity compared with AOA communities. Additionally, AOB amoA genes were ~10-100 times more abundant than AOA amoA genes, and AOB abundance was more strongly correlated with ammonia transformation rates than AOA abundance in most experiments, indicating that particle-attached AOB were more important than AOA in the hypereutrophic urban river. This study adds to our knowledge of particle-attached microorganism oxidation of ammonia
Sustained release ivermectin-loaded solid lipid dispersion for subcutaneous delivery: in vitro and in vivo evaluation
This work aimed to develop a sustained release solid dispersion of ivermectin (IVM-SD) in a lipid matrix (hydrogenated castor oil, HCO) for subcutaneous delivery. Solvent-melting technology was employed to prepare IVM-SDs using HCO. The physicochemical properties of the IVM-SDs were evaluated by scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and Fourier transform infrared spectroscopy (FTIR). The release of IVM from IVM-SDs was evaluated with HPLC in vitro. Pharmacokinetics of IVM was studied in rabbits following a single subcutaneous administration of IVM-SD formulations. The efficacy of IVM-SD against the ear mange mite was evaluated in rabbits. IVM was completely dispersed in HCO in an amorphous state at a drug:carrier ratio lower than 1:3. No chemical interactions between drug and carrier were found besides hydrogen bonding for the amorphous IVM-SDs. The amorphous IVM-SDs formulations exhibited a sustained release of IVM versus physical mixtures (PMs) of IVM and HCO. The drug release decreased as the drug:carrier ratios decreased, and the release kinetics of IVM were controlled via diffusion. Cytotoxicity of IVM-SD to MDCK cells was lower than native IVM. The IVM plasma concentration of SD1:3 remained above 1 ng/mL for 49 d. Higher AUC, MRT, and Tmax values were obtained at a SD1:3 relative to the IVM group. The IVM-SD improved almost 1.1-fold bioavailability of drug compared with IVM in rabbits. IVM-SD could provide longer persistence against rabbit’s ear mites than a commercial IVM injection. This study shows that these solid lipid dispersions are a promising approach for the development of subcutaneous IVM formulations
Study on environmental factors affecting the quality of codonopsis radix based on MaxEnt model and all-in-one functional factor
Abstract Owing to the increasing market demand of Codonopsis Radix, the cropper blindly cultivates to expand planting area for economic benefits, which seriously affects the quality of Codonopsis Radix. Therefore, this study synthesized 207 batches of Codonopsis Radix and 115 ecological factors, and analyzed the suitable planting areas of Codonopsis pilosula under current and future climate change based on Geographic Information System (GIS) and MaxEnt model. Secondly, we evaluated the quality of Codonopsis Radix based on the all-in-one functional factor including chromatographic fingerprint, the index components, the effective compounds groups, the nutritional components, and the nutritional elements, and the quality regionalization of Codonopsis Radix was analyzed. Finally, the ecological factors affecting the accumulation of effective components of Codonopsis Radix were analyzed. This study found for the first time that the highly suitable area of Codonopsis pilosula was mainly distributed in the Weihe River system and the Bailongjiang River system in Gansu Province. There were differences in the quality of Codonopsis Radix from different ecologically suitable areas based on the all-in-one functional factors, and the comprehensive high-quality area of Codonopsis Radix was mainly distributed in Longnan and Longxi district of Gansu Province. The precipitation, temperature and altitude play a key role in the accumulation of chemical components in the 10 ecological factors affecting the distribution of Codonopsis pilosula. Under future climatic conditions, the highly suitable area of Codonopsis pilosula is decreased
Development of Polyclonal Antibodies for Detection of Diosbulbin B‑Derived <i>cis</i>-Enedial Protein Adducts
Diosbulbin
B (DSB), a major component of herbal medicine <i>Dioscorea bulbifera</i> L. (DB), can be metabolized to an electrophilic
intermediate, DSB-derived <i>cis</i>-enedial (DDE). DDE
was suggested to contribute to the hepatotoxicity observed in experimental
animals and humans after their exposure to DSB. Our previous work
found that DDE reacted with primary amino and/or sulfhydryl groups
of hepatic protein. The objective of the study was to develop polyclonal
antibodies that can recognize DDE-derived protein adducts. Immunogens
synthesized from DDE and keyhole limpet hemocyanin were employed to
raise polyclonal antibodies in rabbits. An enzyme-linked immunosorbent
assay (ELISA) demonstrated high titers of antisera obtained from immunized
rabbits. Immunoblot analysis showed that DDE-modified bovine serum
albumin (BSA) was recognized by the obtained polyclonal antibodies
in a concentration-dependent manner and without cross-reaction to
native BSA. Competitive ELISA and competitive immunoblot analyses
defined the specificity of the antibodies to recognize BSA modified
by DDE. Immunoblot analysis also detected a multitude of chemiluminescent
bands with a variety of molecular weights in liver homogenates that
were harvested from mice treated with DSB. In summary, we have successfully
raised polyclonal antibodies to detect protein adducts derived from
DDE