Load monitoring and output power control of a wireless power transfer system without any wireless communication feedback

For mid-range wireless power applications, the load is normally far away from the power source. In this project, a new method is proposed to determine the load impedance and load power without using any direct output feedback. Based only on the information of the input voltage and current, the load impedance and load power can be monitored and controlled without using any wired or wireless feedback from the load. This new method can therefore eliminate the need for any directly measured output feedback, which was previously thought to be essential. It also makes the power control of a wireless power transfer very simple. The concept is verified by the comparison between the computed results and practical results of an 8-ring domino wireless power transfer system. A good degree of accuracy has been achieved in the verification. 2013 IEEE.published_or_final_versio

Monitoring of multiple loads in wireless power transfer systems without direct output feedback

In this paper, a computational method that uses only the input voltage and current to identify the impedances of multiple loads in wireless power transfer systems without any direct load measurements is proposed. The method has been practically realized in a wireless power domino-resonator system comprising 8 resonators. A good degree of accuracy has been achieved in the practical verification. Although the method is demonstrated in a relatively complex system, the principle applies to any wireless power transfer system with 3 or more coil-resonators. Without the requirements for direct load measurements, control circuitry of a wireless power transfer system with multiple loads can avoid the needs for using wireless communication system for feedback purposes. © 2014 IEEE.published_or_final_versio

Sequence Variations of Full-Length Hepatitis B Virus Genomes in Chinese Patients with HBsAg-Negative Hepatitis B Infection

BACKGROUND: The underlying mechanism of HBsAg-negative hepatitis B virus (HBV) infection is notoriously difficult to elucidate because of the extremely low DNA levels which define the condition. We used a highly efficient amplification method to overcome this obstacle and achieved our aim which was to identify specific mutations or sequence variations associated with this entity. METHODS: A total of 185 sera and 60 liver biopsies from HBsAg-negative, HBV DNA-positive subjects or known chronic hepatitis B (CHB) subjects with HBsAg seroclearance were amplified by rolling circle amplification followed by full-length HBV genome sequencing. Eleven HBsAg-positive CHB subjects were included as controls. The effects of pivotal mutations identified on regulatory regions on promoter activities were analyzed. RESULTS: 22 and 11 full-length HBV genomes were amplified from HBsAg-negative and control subjects respectively. HBV genotype C was the dominant strain. A higher mutation frequency was observed in HBsAg-negative subjects than controls, irrespective of genotype. The nucleotide diversity over the entire HBV genome was significantly higher in HBsAg-negative subjects compared with controls (p = 0.008) and compared with 49 reference sequences from CHB patients (p = 0.025). In addition, HBsAg-negative subjects had significantly higher amino acid substitutions in the four viral genes than controls (all p<0.001). Many mutations were uniquely found in HBsAg-negative subjects, including deletions in promoter regions (13.6%), abolishment of pre-S2/S start codon (18.2%), disruption of pre-S2/S mRNA splicing site (4.5%), nucleotide duplications (9.1%), and missense mutations in "alpha" determinant region, contributing to defects in HBsAg production. CONCLUSIONS: These data suggest an accumulation of multiple mutations constraining viral transcriptional activities contribute to HBsAg-negativity in HBV infection.published_or_final_versio

Front-End Monitoring of Multiple Loads in Wireless Power Transfer Systems Without Wireless Communication Systems

5siThis paper describes a method for monitoring multiple loads from the front end of a wireless power transfer system without using any wireless communication systems. A mathematical approach based on scanning the frequency around the resonant frequency has been developed for deriving the load conditions. The proposal requires only information of the input voltage and current, thereby eliminating the requirements of using wireless communication systems for feedback control. The proposal has been practically confirmed in hardware prototype with good results.reservedmixedYin, J.; Lin, D.; Lee, C. K.; Parisini, T.; Hui, S. Y. R.Yin, J.; Lin, D.; Lee, C. K.; Parisini, Thomas; Hui, S. Y. R

Inferring Influenza Infection Attack Rate from Seroprevalence Data

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A longitudinal study of infection attack rates among hospital outpatients in Hong Kong during the epidemic of the human swine influenza A/H1N1 virus in 2009 by tracking temporal changes in age-specific seroprevalence rates

Poster Presentations: Emerging / Infectious Diseases: abstract no. P110-Ab0092Conference Theme: Translating Health Research into Policy and Practice for Health of the Populationpublished_or_final_versio

Damaged DNA-binding protein 2 (DDB2) protects against UV irradiation in human cells and Drosophila

<p>Abstract</p> <p>Background</p> <p>We observed previously that cisplatin-resistant HeLa cells were cross-resistant to UV light due to accumulation of DDB2, a protein implicated in DNA repair. More recently, we found that cFLIP, which represents an anti-apoptotic protein whose level is induced by DDB2, was implicated in preventing apoptosis induced by death-receptor signaling. In the present study, we investigated whether DDB2 has a protective role against UV irradiation and whether cFLIP is also involved in this process.</p> <p>Methods</p> <p>We explored the role of DDB2 in mediating UV resistance in both human cells and Drosophila. To do so, DDB2 was overexpressed by using a full-length open reading frame cDNA. Conversely, DDB2 and cFLIP were suppressed by using antisense oligonucleotides. Cell survival was measured using a colony forming assay. Apoptosis was monitored by examination of nuclear morphology, as well as by flow cytometry and Western blot analyses. A transcription reporter assay was also used to assess transcription of cFLIP.</p> <p>Results</p> <p>We first observed that the cFLIP protein was upregulated in UV-resistant HeLa cells. In addition, the cFLIP protein could be induced by stable expression of DDB2 in these cells. Notably, the anti-apoptotic effect of DDB2 against UV irradiation was largely attenuated by knockdown of cFLIP with antisense oligonucleotides in HeLa cells. Moreover, overexpression of DDB2 did not protect against UV in VA13 and XP-A cell lines which both lack cFLIP. Interestingly, ectopic expression of human DDB2 in <it>Drosophila </it>dramatically inhibited UV-induced fly death compared to control GFP expression. On the other hand, expression of DDB2 failed to rescue a different type of apoptosis induced by the genes <it>Reaper </it>or <it>eiger</it>.</p> <p>Conclusion</p> <p>Our results show that DDB2 protects against UV stress in a cFLIP-dependent manner. In addition, the protective role of DDB2 against UV irradiation was found to be conserved in divergent living organisms such as human and <it>Drosophila</it>. In addition, UV irradiation may activate a cFLIP-regulated apoptotic pathway in certain cells.</p

Glucose lowering effect of transgenic human insulin-like growth factor-I from rice: in vitro and in vivo studies

<p>Abstract</p> <p>Background</p> <p>Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains.</p> <p>Results</p> <p>The plant-codon-optimized hIGF-I was introduced into rice via <it>Agrobacterium</it>-mediated transformation. To enhance the stability and yield of rhIGF-I, the endoplasmic reticulum-retention signal and glutelin signal peptide were used to deliver rhIGF-I to endoplasmic reticulum for stable accumulation. We found that only glutelin signal peptide could lead to successful expression of hIGF-I and one gram of hIGF-I rice grain possessed the maximum activity level equivalent to 3.2 micro molar of commercial rhIGF-I. <it>In vitro </it>functional analysis showed that the rice-derived rhIGF-I was effective in inducing membrane ruffling and glucose uptake on rat skeletal muscle cells. Oral meal test with rice-containing rhIGF-I acutely reduced blood glucose levels in streptozotocin-induced and Zucker diabetic rats, whereas it had no effect in normal rats.</p> <p>Conclusion</p> <p>Our findings provided an alternative expression system to produce large quantities of biologically active rhIGF-I. The provision of large quantity of recombinant proteins will promote further research on the therapeutic potential of rhIGF-I.</p

Effect of clinical and virological parameters on the level of neutralizing antibody against pandemic influenza A virus H1N1 2009

Background. Little is known about the antibody response in natural infection by the novel 2009 influenza A (H1N1) virus and its relationship with clinical and virological parameters. The relative lack of background neutralizing antibody against this novel virus provides a unique opportunity for understanding this issue. Methods. Case patients presenting with influenza-like illness who were positive for the pandemic H1 gene by reverse transcription polymerase chain reaction were identified. The serum antibody response was assayed by neutralizing antibody titer (NAT) against the virus in 881 convalescent donors. We retrospectively analyzed clinical parameters and viral load. Results. Ninety percent of the 881 convalescent donors had seroprotective titer of 1:40 or greater. The geometric mean titer of donors with convalescent NAT measured between day 21 and 42 was 1:101.1. Multivariate analysis by ordinal regression showed that pneumonia (odds ratio, 3.39; 95% confidence interval, 1.49-9-7.61; P=.004) and sputum production (odds ratio, 1.75; 95% CI, 1.01-3.01; P=.046) were the 2 independent factors associated with a higher level of convalescent NAT. Being afebrile on influenza presentation was associated with subsequent poor NAT (<1:40) response (P = .04). A positive correlation between the nasopharyngeal viral load on presentation and the convalescent NAT was demonstrated (Spearman correlation r, 0.238; P = .026). Conclusions. About 10% of these convalescent patients do not have a seroprotective NAT and may benefit from vaccination to prevent reinfection. The convalescent NAT correlated well with the initial viral load and was independently associated with severity of the viral illness, including pneumonia. The findings provide both the clinical and virological markers for identifying potential convalescent plasma donors with high serum NAT, which can be used to produce hyperimmune intravenous immunoglobulin in a randomized treatment trial for patients with severe pandemic H1N1 infection. © 2010 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio

Prevalence of occult hepatitis B infection in a highly endemic area for chronic hepatitis B: A study of a large blood donor population

Background and aims: The aim of the present study was to determine the population prevalence of occult hepatitis B (OHB) infection and its clinical profile in a highly endemic area of chronic hepatitis B virus disease. Methods: OHB was first identified by individual sample testing for hepatitis B surface antigen (HBsAg) followed by nucleic acid testing (NAT) and vice versa for 3044 (cohort 1, stored sera from donation within 1 year) and 9990 (cohort 2, prospective study) blood donors, respectively. OHB was confirmed meticulously by ≥2 out of 3 tests with detectable hepatitis B virus (HBV) DNA using a sensitive standardised assay. Detailed serology and viral load in the serum and liver were studied. Results: The prevalence of OHB was 0.13% (4/3044) and 0.11% (11/9967) for cohort 1 and 2, respectively. In cohort 2, 10 out of 11 OHB samples were positive for anti-HBc (hepatitis B core antigen) antibody (all were immunoglobulin G). Seven had detectable anti-HBs. The serum HBV DNA levels were extremely low (highest 14.1 IU/ml). Of the six donors who underwent liver biopsies, all had normal liver biochemistry, extremely low liver HBV DNA (highest 6.21 copies/cell) and nearly normal liver histology. For those with viral sequence generation, none had the common HBsAg mutant G145R. Conclusions: The prevalence of OHB in a highly endemic area of chronic HBV was very low, thus implying a low impact on transfusion services. To implement universal screening, the high cost of NAT should be taken into account. OHB blood donors had very low HBV replication, and normal liver biochemistry and histology, conferring a favourable prognosis.published_or_final_versio