A Polynomial Digital Pre-Distortion Technique Based on Iterative Architecture

A digital predistortion (DPD) technique based on an iterative adaptation structure is proposed for linearizing power amplifiers (PAs). To obtain proper DPD parameters, a feedback path that converts the PA’s output to a baseband signal is required, and memory is also needed to store the baseband feedback signals. DPD parameters are usually found by an adaptive algorithm by using the transmitted signals and the corresponding feedback signals. However, for the adaptive algorithm to converge to a reliable solution, long feedback samples are required, which increases hardware complexity and cost. Considering that the convergence time of the adaptive algorithm highly depends on the initial condition, we propose a DPD technique that requires relatively shorter feedback samples. Specifically, the proposed DPD iteratively utilizes the short feedback samples in memory while keeping and using the DPD parameters found at the former iteration as the initial condition at the next iteration. Computer simulation shows that the proposed technique performs better than the conventional technique, as the former requires much shorter feedback memory than the latter

Robust Digital Predistortion in Saturation Region of Power Amplifiers

This paper proposes a digital predistortion (DPD) technique to improve linearization performance when the power amplifier (PA) is driven near the saturation region. The PA is a non-linear device in general, and the nonlinear distortion becomes severer as the output power increases. However, the PA’s power efficiency increases as the PA output power increases. The nonlinearity results in spectral regrowth, which leads to adjacent channel interference, and degrades the transmit signal quality. According to our simulation, the linearization performance of DPD is degraded abruptly when the PA operates in its saturation region. To relieve this problem, we propose an improved DPD technique. The proposed technique performs on/off control of the adaptive algorithm based on the magnitude of the transmitted signal. Specifically, the adaptation normally works for small and medium signals while it stops for large signals. Therefore, harmful coefficient updates by saturated signals can be avoided. A computer simulation shows that the proposed method can improve the linearization performance compared with the conventional DPD method in highly driven PAs

Cystamine induces AIF-mediated apoptosis through glutathione depletion

AbstractCystamine and its reduced form cysteamine showed protective effects in various models of neurodegenerative disease, including Huntington's disease and Parkinson's disease. Other lines of evidence demonstrated the cytotoxic effect of cysteamine on duodenal mucosa leading to ulcer development. However, the mechanism for cystamine cytotoxicity remains poorly understood. Here, we report a new pathway in which cystamine induces apoptosis by targeting apoptosis-inducing factor (AIF). By screening of various cell lines, we observed that cystamine and cysteamine induce cell death in a cell type-specific manner. Comparison between cystamine-sensitive and cystamine-resistant cell lines revealed that cystamine cytotoxicity is not associated with unfolded protein response, reactive oxygen species generation and transglutaminase or caspase activity; rather, it is associated with the ability of cystamine to trigger AIF nuclear translocation. In cystamine-sensitive cells, cystamine suppresses the levels of intracellular glutathione by inhibiting γ-glutamylcysteine synthetase expression that triggers AIF translocation. Conversely, glutathione supplementation completely prevents cystamine-induced AIF translocation and apoptosis. In rats, cysteamine administration induces glutathione depletion and AIF translocation leading to apoptosis of duodenal epithelium. These results indicate that AIF translocation through glutathione depletion is the molecular mechanism of cystamine toxicity, and provide important implications for cystamine in the neurodegenerative disease therapeutics as well as in the regulation of AIF-mediated cell death

TRAIL Enhances Apoptosis of Human Hepatocellular Carcinoma Cells Sensitized by Hepatitis C Virus Infection: Therapeutic Implications

Hepatitis C virus (HCV) infection causes chronic liver diseases leading to hepatocellular carcinoma (HCC) and liver failure. We have previously shown that HCV sensitizes hepatocytes to mitochondrial apoptosis via the TRAIL death receptors DR4 and DR5. Although TRAIL and its receptors are selective targets for cancer therapy, their potential against HCC with chronic HCV infection has not been explored yet. Here we show that HCV induces DR4/DR5-dependent activation of caspase-8 leading to elevation of apoptotic signaling in infected cells and also present TRAIL effect in HCV-induced apoptotic signaling. HCV induced proteolytic cleavage of caspase-9 by stimulating DR4 and DR5, resulting in subsequent cleavage of caspase-3. Further, HCV-induced proteolytic cleavage in caspase-8, caspase-9, and caspase-3 was enhanced in the presence of recombinant TRAIL. HCV-induced cleavage in caspase-9 and increase in caspase-3/7 activity was completely suppressed by silencing of either DR4 or DR5. Perturbing DR4/DR5-caspase-8 signaling complex by silencing DR4 and DR5 or by chemical inhibitor specific to caspase-8 led to decrease of HCV-induced cleavage of poly(ADP-ribose) polymerase (PARP), a substrate for caspase-3 during apoptosis, indicating the functional role of caspase-8 in HCV-induced apoptotic signaling network. Furthermore, TRAIL enhanced PARP cleavage in apoptotic response induced by HCV infection, indicating the effect of TRAIL for the induction of selective apoptosis of HCC cells infected with HCV. Given the importance of apoptosis in HCC development, our data suggest that HCV-induced DR4 and DR5 may be considered as an attractive target for TRAIL therapy against HCC with chronic HCV infection

Dining-out behaviors of residents in Chuncheon city, Korea, in comparison to the Korean National Health and Nutrition Survey 2001

Dining-out behavior is associated not only with socio-demographic characteristics such as gender, education, occupation, residence, and marital status, but also with individual preferences, such as eating-out activities, interests, and opinions. We investigated dining-out behaviors and their associated factors. Announcements by health practioners and the Chief of Dong Office were used to recruit 739 residents (217 males and 522 females) in Chuncheon, Korea. Information on the frequency and reasons for eating out, the standards for meal selection, and the overall satisfaction with restaurants, based on taste, nutrition, amount, price, service, sanitation, and subsidiary facilities of restaurants, was obtained through personal interviews with a structured questionnaire. Among all respondents, 46.3% of subjects ate outside of the home once or twice a month, and 33.8% reported that they ate out only a few times a year, or never. This was much higher than the national average of 52.0% as reported by the Korean National Health and Nutrition Survey (KNHNS) in 2001. The frequency of eating out differed significantly according to age (p=0.001), family income (p<0.001), residential area (p<0.001), and educational level (p<0.001). The most common reasons for dining out were meetings (46.7%), followed by special celebrations (15.4%), and enjoyment (11.2%). Korean food (55.3%) was the most frequently selected type of meal when eating out, and food was most often selected based on personal preferences (41.4%) and taste (29.8%); only 5.5% and 7.7% of subjects considered nutrition or other factors (e.g., sanitation), respectively. The results showed that the frequency of eating out for Chuncheon residents was much lower than the national average; in addition, eating-out behaviors depended on the residents' socio-demographic and personal characteristics

Alpha-2-Macroglobulin as a New Promising Biomarker Improving the Diagnostic Sensitivity of Bovine Paratuberculosis

Johne&apos;s disease (JD) is a chronic granulomatous enteritis of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), which induces persistent diarrhea and cachexia. JD causes huge economic losses to the dairy industry due to reduced milk production and premature culling. Infected animals excrete MAP via feces during the prolonged subclinical stage without exhibiting any clinical signs. Therefore, accurate detection of subclinical stage animals is crucial for successful eradication of JD in the herd. In the current study, we analyzed serum samples of MAP-infected and non-infected cattle to identify potential biomarker candidates. First, we identified 12 differentially expressed serum proteins in subclinical and clinical shedder groups compared to the healthy control group. Second, we conducted ELISA for three selected biomarkers (alpha-2-macroglobulin (A2M), alpha-1-beta glycoprotein, and transthyretin) and compared their diagnostic performance with that of two commercial ELISA diagnostic kits. Serum A2M levels were significantly higher in the MAP-exposed, subclinical shedder, subclinical non-shedder, and clinical shedder groups than in the healthy control group, suggesting its possible use as a diagnostic biomarker for MAP infection. Furthermore, A2M demonstrated a sensitivity of 90.4%, and a specificity of 100% while the two commercial ELISA kits demonstrated a sensitivity of 67.83 and 73.04% and a specificity of 100%, respectively. In conclusion, our results suggest that measuring A2M by ELISA can be used as a diagnostic tool to detect MAP infection, considerably improving the detection rate of subclinical shedders and MAP-exposed animals that are undetectable using current diagnostic tools

Monoclonal Antibodies to Human Transglutaminase 4

Transglutaminase 4 (TG4) is a member of the enzyme family that catalyzes the calcium-dependent post-translational modification of proteins via cross-linking, polyamination, or deamidation. TG4 exhibits prostate-specific expression pattern and plays a crucial role in the formation of the copulatory plug in rodents. However, the physiological function(s) of human TG4 remains speculative. Human TG4 has been postulated to participate in the maturation process of sperm by modifying its cell surface, which results in suppression of sperm antigenicity in the female genital tract. To better understand the pathophysiological role of TG4 in prostate tissue, we generated monoclonal antibodies (MAb) against human TG4 in mice by repeated injections with the recombinant human TG4. Western blot analysis demonstrated that the selected MAbs react specifically with TG4, but not with other isoenzymes of the TG family. Immunocytochemical and immunohistochemical analyses showed that specific staining is observed with the cells overexpressing TG4 and with the paraffin-embedded prostate tissue specimens obtained from the benign prostate hyperplasia and prostate cancer patients, respectively. Our results indicate that these MAbs are suitable for detecting TG4 in the cultured cells or prostate tissues for investigating the biological functions of human TG4.Shin DM, 2004, J BIOL CHEM, V279, P15032, DOI 10.1074/jbc.M308734200Jeon JH, 2003, EMBO J, V22, P5273Lorand L, 2003, NAT REV MOL CELL BIO, V4, P140, DOI 10.1038/nrm1014Jeon JH, 2002, BIOCHEM BIOPH RES CO, V294, P818An G, 1999, UROLOGY, V54, P1105Dubbink HJ, 1999, GENE, V240, P261Dubbink HJ, 1999, LAB INVEST, V79, P141Choi K, 1998, EXP MOL MED, V30, P41Esposito C, 1996, J BIOL CHEM, V271, P27416Dubbink HJ, 1996, BIOCHEM J, V315, P901SEITZ J, 1991, BIOCHIM BIOPHYS ACTA, V1078, P139PAONESSA G, 1984, SCIENCE, V226, P852MUKHERJEE DC, 1983, SCIENCE, V219, P989WILLIAMSASHMAN HG, 1977, BIOCHEM BIOPH RES CO, V79, P1192WILLIAMS.HG, 1972, P NATL ACAD SCI USA, V69, P2322

Usefulness of Multiplex Real-Time PCR for Simultaneous Pathogen Detection and Resistance Profiling of Staphylococcal Bacteremia

Staphylococci are the leading cause of nosocomial blood stream infections. Fast and accurate identification of staphylococci and confirmation of their methicillin resistance are crucial for immediate treatment with effective antibiotics. A multiplex real-time PCR assay that targets mecA, femA specific for S. aureus, femA specific for S. epidermidis, 16S rRNA for universal bacteria, and 16S rRNA specific for staphylococci was developed and evaluated with 290 clinical blood culture samples containing Grampositive cocci in clusters (GPCC). For the 262 blood cultures identified to the species level with the MicroScan WalkAway system (Siemens Healthcare Diagnostics, USA), the direct real-time PCR assay of positive blood cultures showed very good agreement for the categorization of staphylococci into methicillin-resistant S. aureus (MRSA), methicillin-susceptible S. aureus (MSSA), methicillin-resistant S. epidermidis (MRSE), methicillin-susceptible S. epidermidis (MSSE), methicillin-resistant non-S. epidermidis CoNS (MRCoNS), and methicillin-susceptible non-S. epidermidis CoNS (MSCoNS) ( = 0.9313). The direct multiplex real-time PCR assay of positive blood cultures containing GPCC can provide essential information at the critical point of infection with a turnaround time of no more than 4 h. Further studies should evaluate the clinical outcome of using this rapid real-time PCR assay in glycopeptide antibiotic therapy in clinical settings

Effect of emergency medical service use on time interval from symptom onset to hospital admission for definitive care among patients with intracerebral hemorrhage: a multicenter observational study

Objective This study evaluated whether emergency medical service (EMS) use was associated with early arrival and admission for definitive care among intracerebral hemorrhage (ICH) patients. Methods Patients with ICH were enrolled from 29 hospitals between November 2007 and December 2012, excluding those patients with subarachnoid hemorrhage, traumatic ICH, and missing information. The patients were divided into four groups based on visit type to the definitive hospital emergency department (ED): direct visit by EMS (EMS-direct), direct visit without EMS (non-EMS-direct), transferred from a primary hospital by EMS (EMS-transfer), and transferred from a primary hospital without EMS (non-EMS-transfer). The outcomes were the proportions of participants within early (<1 hr) definitive hospital ED arrival from symptom onset (pS2ED) and those within early (<4 hr) admission from symptom onset (pS2AD). Adjusted odds ratios were calculated to determine the association between EMS use and outcomes with and without inter-hospital transfer. Results A total of 6,564 patients were enrolled. The adjusted odds ratios (95% confidence intervals) for pS2ED were 22.95 (17.73–29.72), 1.11 (0.67–1.84), and 7.95 (6.04–10.46) and those for pS2AD were 5.56 (4.70–6.56), 0.96 (0.71–1.30), and 2.35 (1.94–2.84) for the EMS-direct, EMS-transfer, and non-EMS-direct groups compared with the non-EMS-transfer group, respectively. Through the interaction model, EMS use was significantly associated with early arrival and admission among direct visiting patients but not with transferred patients. Conclusion EMS use was significantly associated with shorter time intervals from symptom onset to arrival and admission at a definitive care hospital. However, the effect disappeared when patients were transferred from a primary hospital