Academic literature on the topic 'HEPHC'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'HEPHC.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "HEPHC"
1
Rakotomanga, M., M. Saint-Pierre-Chazalet, and P. M. Loiseau. "Alteration of Fatty Acid and Sterol Metabolism in Miltefosine-Resistant Leishmania donovani Promastigotes and Consequences for Drug-Membrane Interactions." Antimicrobial Agents and Chemotherapy 49, no. 7 (July 2005): 2677–86. http://dx.doi.org/10.1128/aac.49.7.2677-2686.2005.
Full textAbstract:
ABSTRACT Miltefosine (hexadecylphosphocholine [HePC]) is the first orally active drug approved for the treatment of visceral leishmaniasis. In order to investigate the biochemical modifications occurring in HePC-resistant (HePC-R) Leishmania donovani promastigotes, taking into account the lipid nature of HePC, we investigated their fatty acid and sterol metabolisms. We found that the content of unsaturated phospholipid alkyl chains was lower in HePC-R parasite plasma membranes than in those of the wild type, suggesting a lower fluidity of HePC-R parasite membranes. We also demonstrated that HePC insertion within an external monolayer was more difficult when the proportion of unsaturated phospholipids decreased, rendering the HePC interaction with the external monolayer of HePC-R parasites more difficult. Furthermore, HePC-R parasite membranes displayed a higher content of short alkyl chain fatty acids, suggesting a partial inactivation of the fatty acid elongation enzyme system in HePC-R parasites. Sterol biosynthesis was found to be modified in HePC-R parasites, since the 24-alkylated sterol content was halved in HePC-R parasites; however, this modification was not related to HePC sensitivity. In conclusion, HePC resistance affects three lipid biochemical pathways: fatty acid elongation, the desaturase system responsible for fatty acid alkyl chain unsaturation, and the C-24-alkylation of sterols.
2
Yeh, Kwo-yih, Mary Yeh, Laura Mims, and Jonathan Glass. "Iron feeding induces ferroportin 1 and hephaestin migration and interaction in rat duodenal epithelium." American Journal of Physiology-Gastrointestinal and Liver Physiology 296, no. 1 (January 2009): G55—G65. http://dx.doi.org/10.1152/ajpgi.90298.2008.
Full textAbstract:
Intestinal iron absorption involves proteins located in the brush border membrane (BBM), cytoplasm, and basolateral membrane (BLM) of duodenal enterocytes. Ferroportin 1 (FPN1) and hephaestin (Heph) are necessary for transport of iron out of enterocytes, but it is not known whether these two proteins interact during iron absorption. We first examined colocalization of the proteins by cotransfection of HEK293 cells with pDsRed-FPN1 with pEmGFP-Heph or with the COOH-terminal truncated pEmGFP-HephΔ43 or -HephΔ685 and found that FPN1 and Heph with or without the COOH terminus colocalized. In rat duodenal enterocytes, within 1 h of iron feeding prominent migration of FPN1 from the apical subterminal zone to the basal subnuclear zone of the BLM occurred and increased to at least 4 h after feeding. Heph exhibited a similar though less prominent migration after iron ingestion. Analysis using rat duodenal epithelial cell sheets demonstrated that 1) by velocity sedimentation ultracentrifugation, FPN1 and Heph occupied vesicles of different sizes prior to iron feeding and migrated to similar fractions 1 h after iron feeding; 2) by blue native/SDS-PAGE, FPN1, and Heph interacted to form two complexes, one containing dimeric FPN1 and intact Heph and the other consisting of monomeric FPN1 and a Heph fragment; and 3) by immunoprecipitation, anti-Heph or anti-FPN1 antiserum coimmunoprecipitated FPN1 and Heph. Thus the data indicate that FPN1 and Heph migrate and interact during iron feeding and suggest that dimeric FPN1 is associated with intact Heph.
3
Tseng, Chung-Chih, Tah-Wei Chu, Ridha Danata, Yenny Risjani, Hui-Tsu Shih, and Shao-Yang Hu. "Hepcidin-Expressing Fish Eggs as A Novel Food Supplement to Modulate Immunity against Pathogenic Infection in Zebrafish (Danio rerio)." Sustainability 12, no. 10 (May 15, 2020): 4057. http://dx.doi.org/10.3390/su12104057.
Full textAbstract:
Hepcidin antimicrobial peptides are difficult to produce in prokaryotic expression systems due to their complex structure and antimicrobial activity. Although synthetic hepcidin provides an alternative to solve this issue, its high cost limits its practical application in various industries. The present study used zebrafish eggs as bioreactors to produce convict cichlid (Amatitlania nigrofasciata) hepcidin (AN-hepc) using the oocyte-specific zona pellucida (zp3) promoter. The expression plasmid pT2-ZP3-AN-hepc-ZP3-EGFP, using EGFP as a reporter of AN-hepc expression, was designed to establish the transgenic line Tg(ZP3:AN-hepc:ZP3:EGFP) for the expression of AN-hepc. The AN-hepc peptide was produced successfully in fertilized eggs, as evidenced by RT-PCR and Western blotting. The AN-hepc-expressing eggs exhibited antimicrobial activity against a variety of aquatic pathogens and antibiotic-resistant pathogens, suggesting that the AN-hepc expressed in fish eggs was bioactive. The immunomodulatory effects of AN-hepc-expressing fertilized eggs on zebrafish innate immunity were evaluated by determining the expression of indicator genes after feeding with AN-hepc-expressing fertilized eggs for two months. Zebrafish supplementation with AN-hepc-expressing fertilized eggs significantly increased the expression of innate immunity-related genes, including IL-1β, IL-6, IL-15, TNF-α, NF-κb, complement C3b, lysozyme and TLR-4a. The zebrafish administered AN-hepc-expressing eggs exhibited higher cumulative survival than fish supplemented with wild-type and control eggs after infection with Aeromonas hydrophila and Streptococcus iniae. In conclusion, the present results showed that supplementation with AN-hepc-expressing fish eggs enhanced zebrafish innate immunity against pathogenic infections, suggesting that fertilized eggs containing AN-hepc have the potential to be developed as a food supplement for improving health status in aquaculture.
4
Li, Jie, Xuelan Shang, Yan Liang, Wenjie Yang, Zhe Wang, and Hezhao Ji. "Assessment of the Hepatitis C Surveillance System in Henan, China: 2014~2016." BioMed Research International 2018 (September 26, 2018): 1–8. http://dx.doi.org/10.1155/2018/8942152.
Full textAbstract:
Objectives. To access the Hepatitis C (HepC) surveillance program in Henan, China, 2014~2016. Methods. A total of 8,448 HepC-relevant cases were reviewed and this data was then inquired against the 6,147 archived HepC reports during the same time period. The performance of the HepC surveillance program was evaluated using parameters including Timely Reporting Rate (TRR), pairs of Report Sensitivity (RS)/Underreporting Rate (UR), and False Report Rate (FRR)/Predictive Value Positive (PVP). Longitudinal comparisons of report quality over the three examined years were conducted to determine the temporal trend of HepC surveillance accountability. Results. All HepC reports were submitted within 24 hours post diagnosis, and TRR rates for all examined years remained at 100%. The RS rates significantly improved overtime for clinically diagnosed HepC cases (CDHC) (2014:60.32%, 2015:68.13%, and 2016:82.83%), whereas the RS for confirmed HepC cases (CHC) remained relatively constant (80.77%, 88.64%, and 85.82%). The FRR rates for CDHC and CHC in 2015~2016 were both approximately 30% but at 23.61% and 51.85%, respectively, in 2014. Conclusions. The HepC surveillance system in Henan remains effective and consistent improvement in report accountability was observed over time. However, some issues concerning especially RS and PVP remained to be addressed for ensuring data accountsbility.
5
Rakotomanga, M., S. Blanc, K. Gaudin, P. Chaminade, and P. M. Loiseau. "Miltefosine Affects Lipid Metabolism in Leishmania donovani Promastigotes." Antimicrobial Agents and Chemotherapy 51, no. 4 (January 22, 2007): 1425–30. http://dx.doi.org/10.1128/aac.01123-06.
Full textAbstract:
ABSTRACT Miltefosine (hexadecylphosphocholine [HePC]) is the first orally active antileishmanial drug. Transient HePC treatment of Leishmania donovani promastigotes at 10 μM significantly reduced the phosphatidylcholine content and enhanced the phosphatidylethanolamine (PE) content in parasite membranes, suggesting a partial inactivation of PE-N-methyltransferase. Phospholipase D activity did not seem to be affected by HePC. In addition, the enhancement of the lysophosphatidylcholine content could be ascribed to phospholipase A2 activation. Moreover, transient HePC treatment had no effect on the fatty acid alkyl chain length or the fatty acid unsaturation rate. Concerning sterols, we found a strong reduction of the C24 alkylated sterol content, and the enhancement of the cholesterol content could be the result of the HePC condensation effect with sterols. Because some of the effects observed after transient HePC treatment were different from those previously observed in HePC-resistant parasites, it could be hypothesized that continuous in vitro drug pressure induces the mechanisms of regulation in Leishmania lipid metabolism.
6
Mena, Natalia P., Andrés Esparza, Victoria Tapia, Pamela Valdés, and Marco T. Núñez. "Hepcidin inhibits apical iron uptake in intestinal cells." American Journal of Physiology-Gastrointestinal and Liver Physiology 294, no. 1 (January 2008): G192—G198. http://dx.doi.org/10.1152/ajpgi.00122.2007.
Full textAbstract:
Hepcidin (Hepc) is considered a key mediator in iron trafficking. Although the mechanism of Hepc action in macrophages is fairly well established, much less is known about its action in intestinal cells, one of the main targets of Hepc. The current study investigated the effects of physiologically generated Hepc on iron transport in Caco-2 cell monolayers and rat duodenal segments compared with the effects on the J774 macrophage cell line. Addition of Hepc to Caco-2 cells or rat duodenal segments strongly inhibited apical 55Fe uptake without apparent effects on the transfer of 55Fe from the cells to the basolateral medium. Concurrently, the levels of divalent metal transporter 1 (DMT1) mRNA and protein in Caco-2 cells decreased while the mRNA and protein levels of the iron export transporter ferroportin did not change. Plasma membrane localization of ferroportin was studied by selective biotinylation of apical and basolateral membrane domains; Hepc induced rapid internalization of ferroportin in J774 cells but not in Caco-2 cells These results indicate that the effect of Hepc is cell dependent: in macrophages it inhibits iron export by inducing ferroportin degradation, whereas in enterocytes it inhibits apical iron uptake by inhibiting DMT1 transcription. Our results highlight the crucial role of Hepc in the control of intestinal iron absorption.
7
Graf v.d. Schulenburg, M. "HEPAC – New Editor-in-chief." European Journal of Health Economics (HEPAC) 2, no. 1 (March 2001): 1. http://dx.doi.org/10.1007/pl00012213.
Full text
8
Myers, John, Michael Smith, Claudia Espinosa, Charles Woods, and Scott Duncan. "Is there Failure to Screen for Hepatitis C in Newborns Suffering from Neonatal Abstinence Syndrome?" Open Forum Infectious Diseases 4, suppl_1 (2017): S40—S41. http://dx.doi.org/10.1093/ofid/ofx162.098.
Full textAbstract:
Abstract Background Enormous advances in treating/curing patients suffering from Hepatitis C (HepC) infection have occurred; resulting in many states mandating screening for HepC for older individuals. Unfortunately, no protection of screening exists for newborns. In Kentucky, rates of HepC among pregnant women are the second highest within the U.S., which has been associated to high intravenous drug use. Infants born to those women are at risk of HepC infection and other conditions such as neonatal abstinence syndrome (NAS). The current study examined the rate of HepC screening in a high-risk cohort (newborns suffering from NAS) and it’s impact on policy-making for this vulnerable population. Methods Kentucky Medicaid records, from 2015, were obtained to develop a detailed demographic, behavioral, clinical, and diagnostic data set (n = 152,749). NAS was defined by ICD-9 code 779.5 and ICD-10 code P96.1. HepC screening was defined by CPT codes (CPT 87520 [HCV, direct probe], 87521 [HCV, amplified probe], and 87522 [HCV RNA, Quantitative] or antibody [CPTs 86803–4]). Initially a descriptive study was performed, then multiple logistic regression techniques were used to test what variables impacted the odds of not being screened for HepC. Results A total of 1234 newborns with NAS were identified. The majority showed signs of NAS within 24 hours (64%), were white (68%) and were admitted to the hospital for an average of 24.8 days. Only one-in-three newborns with NAS (n = 412, 33.4%) were screened for HepC. Non-Whites (OR = 1.58, 95% CI 1.45–1.71, P < 0.001) and those living in non-urban areas (OR = 1.42, 95% CI 1.28–1.56, P < 0.001) were the only study variables to significantly impact the odds of not being screened for HepC (for newborns suffering from NAS). Conclusion A high-risk and vulnerable population for HepC may not be getting screened for HepC and thus are being underserved by the health care system. Non-Whites and those in rural areas are the most affected. Solutions and policies need to be focused on this population and area where screening is lacking. Optimization of maternal screening for HepC is crucial in high-risk populations. Disclosures All authors: No reported disclosures.
9
Luque-Ortega, Juan Román, and Luis Rivas. "Miltefosine (Hexadecylphosphocholine) Inhibits Cytochrome c Oxidase in Leishmania donovani Promastigotes." Antimicrobial Agents and Chemotherapy 51, no. 4 (February 5, 2007): 1327–32. http://dx.doi.org/10.1128/aac.01415-06.
Full textAbstract:
ABSTRACT Miltefosine (hexadecylphosphocholine [HePC]) is currently on trial as a first-choice, orally active drug for the treatment of visceral leishmaniasis when resistance to organic pentavalent antimonials becomes epidemic. However, data on the targets involved in its leishmanicidal mechanism have, until now, been only fragmentary. We have carried out a systematic study of the alterations induced on the bioenergetic metabolism of Leishmania donovani promastigotes by HePC. Overnight incubation with HePC caused a significant decline in the intracellular ATP levels of the parasites, together with a reduction in the oxygen consumption rate and mitochondrial depolarization, while the integrity of the plasma membrane remained undamaged. In a further step, the effects of HePC on the respiratory chain were addressed in digitonized parasites. The inhibition of the oxygen consumption rate caused by HePC was not reverted either with the uncoupling agent carbonyl cyanide p-trifluoromethoxyphenylhydrazone or with tetramethyl-p-phenylenediamine plus ascorbate, which feeds the electron transport chain at the level of cytochrome c. These results suggest that cytochrome c oxidase is a likely target in the complex leishmanicidal mechanism of HePC. This was further confirmed from the finding that this enzyme was specifically inhibited in a dose-dependent manner by HePC, but not the cytochrome c reductase, ruling out an unspecific effect of HePC on the respiratory chain.
10
Pérez-Victoria, F. Javier, Santiago Castanys, and Francisco Gamarro. "Leishmania donovani Resistance to Miltefosine Involves a Defective Inward Translocation of the Drug." Antimicrobial Agents and Chemotherapy 47, no. 8 (August 2003): 2397–403. http://dx.doi.org/10.1128/aac.47.8.2397-2403.2003.
Full textAbstract:
ABSTRACT Miltefosine (hexadecylphosphocholine [HePC]) is the first drug approved for the oral treatment of visceral leishmaniasis. As part of a study on the mechanisms of action of this drug and on the rates of resistance to this drug, we have been working in vitro with an Leishmania donovani line that was previously shown to be 15-fold more resistant to HePC. We have studied the accumulation of [14C]HePC by L. donovani promastigotes and have found a drastic reduction (>95%) in the ability of the resistant line to internalize the drug. Binding of HePC to the plasma membrane and drug efflux from preloaded cells were similar in both drug-sensitive and -resistant lines, and no [14C]HePC metabolism was evident in either line. Resistant parasites were also unable to take up other short-chain phospholipid analogs, independently of their polar head group, even though endocytosis remained unaltered. Finally, HePC uptake was temperature and energy dependent and sensitive to the thiol-reactive agent N-ethylmaleimide. We propose that inward translocation of a short-chain phospholipid across the plasma membrane may exist in Leishmania promastigotes and that such activity is defective in the resistant line.
Dissertations / Theses on the topic "HEPHC"
1
Milbourne, Katrina Jane, and n/a. "A randomised controlled trial to investigate the efficacy of heparin and hydrocortisone additive to extend the life of peripheral cannulae in children." University of Canberra. Health Sciences, 2002. http://erl.canberra.edu.au./public/adt-AUC20050530.104945.
Full textAbstract:
Repeated cannulation of children during the course of treatment is distressing for the
child, their family and to their nurses. Some paediatric units endeavour to minimise recannulation
by employing strategies to reduce complications such as phlebitis and
thrombosis formation. One strategy is to infuse low dose heparin and hydrocortisone
(HEPHC). However, its effectiveness in prolonging cannula survival is inconclusive.
There is also concern about the potential risks of administering these preparations to
children.
A randomised, controlled, blinded trial was conducted that examined the effectiveness
of continuous infusion of low dose HEPHC in a group of children requiring long term
intravenous antibiotics in a general paediatric unit. Comparisons of cannula
complications and cannulae survival times were made in children receiving either
continuous infusions of clear fluids or low dose HEPHC.
The results demonstrated that there was no statistically significant difference (Logrank
statistic=l.l, p=0.3) in cannula survival times between the two groups. It was also
found that the bacterial and fungal colonisation of cannula for these children was
extremely low. Based on these findings it is recommended that routine administration
of low dose HEPHC to extend cannula survival time be discontinued. The findings
also support current practice of removing cannula in children only when a complication
occurs on completion of treatment.
2
Ravindranath, Velaga M. "Elucidating the role of mitoferrin (Mfrn), iron regulatory proteins (IRP1 and IRP2) and hephaestin (Heph) in iron metabolism by tagSNP and protein-protein interaction (PPI) analysis." Thesis, London Metropolitan University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639414.
Full textAbstract:
Precisely how Hephaestin (Heph) facilitate iron release from cells is poorly understood. The work in this thesis tried to establish the role of different iron metabolic proteins, Mitoferrin (Mfrn), IRPs and Heph in iron homeostasis. Analysis of 18 tagSNPs in the Mfrn gene was carried out in an AsianCaucasian population to establish any correlation between the Mfrn tagSNPs, haemoglobin levels and birth weight in the presence of covariates such as sex of the fetus, gestational age and mother's booking weight. Two-way ANCOVA analysis was carried out to check if the covariates have any influence on the dependent variable in the presence of fixed factors. From the ANCOVA analysis of Mfrn tagSN Ps it can be concluded that neither the haemoglobin levels nor the birth weight are dependent on the genotype, fetal sex, nor on their interaction. Owing to the significance in identifying the interacting partners of IRPs and Heph to understand more about their role in iron metabolism, protein-protein interaction studies were also carried out. IRPs and Heph genes were successfully cloned with One-Strep tag. Full length clones were sequence confirmed for any variation after PCR. Before carrying out immunoprecipitation to identify the interacting partners, transfection efficiency, viability and the role of magnetic particles on K562 cells was performed by using IRPs and Heph cloned with One-Strep tag. Lipofectamine-L TX plus transfection had more viable cells and higher efficiency compared with magnetic-assisted transfection . Also, this study confirms that magnetic nanoparticles do not have any adverse or significant effect on IRPs during the transfection. An unsuccessful attempt was made to identify the interacting partners of IRPs and Heph by immunoprecipitation. The current thesis work also involved identification of a potential ferroxidase . Ceruloplasmin (Cp) was used as a postive control. Non-denaturing gel eletrophoresis of the K562, MDA-MB-231 and PNT2-C2 cell fractions confirmed the presence of the extra band establishing the ubiquitous nature of the band. Mass spectrometry analysis identified the excised band as Calreticulin (CALR). This is the first report of calreticulin having ferroxidase activity.
Books on the topic "HEPHC"
1
Carter, Royal Wheeler. Stairs from the Dungeon: The Dialogues of a HepC Maniac. PublishAmerica, 2005.
Find full textBook chapters on the topic "HEPHC"
1
Boumaiza, Mohamed, Samia Rourou, Paolo Arosio, and Mohamed Nejib Marzouki. "The Use of Ferritin as a Carrier of Peptides and Its Application for Hepcidin." In BioMechanics and Functional Tissue Engineering [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94408.
Full textAbstract:
Hepcidin a 25-amino-acid and highly disulfide bonded hormone, is the central regulator of iron homeostasis. In this chapter we propose ferritin as a peptide carrier to promote the association of the hybrid hepcidin/ferritin nanoparticle with a particular cell or tissue for therapeutic or diagnostic use. Indeed, human ferritin H-chain fused directly (on its 5’end) with camel mature hepcidin was cloned into the pASK-43 plus vector and expressed using BL21 (DE3) pLys E. coli strain. The transformed E.coli produced efficiently hepcidin-ferritin construct (hepcH), consisting of 213 amino acids with a molecular weight of 24 KDa. The recovered product is a ferritin exposing hepcidin on outer surface. The hepcH monomer was characterized by immunoblotting using a monoclonal antibody specific for human ferritin and a polyclonal antibody specific for hepcidin-25. The results were also confirmed by MALDI-TOF mass spectrometry. The recombinant native human ferritin and the commercial human hepcidin-25 were used as controls in this experiment. The assembly of hepcH, as an heteropolymer molecule, was performed in presence of denatured human ferritin-H and -L chains. After cysteine oxidation of the recombinant nanoparticles, cellular binding assays were performed on mammalian cells such as mouse monocyte–macrophage cell line J774, HepG2 and COS7.
2
Doherty, Peter C. "HIV/AIDS." In Pandemics. Oxford University Press, 2013. http://dx.doi.org/10.1093/wentk/9780199898107.003.0008.
Full textAbstract:
Is HIV still a concern? That depends a lot on how and where we live. The current situation for HIV is a bit like that discussed above for the HepC virus in that, while HIV is active in every nation on the planet, the...
Conference papers on the topic "HEPHC"
1
Cohn, Marvin J. "Life Management of Main Steam and Hot Reheat Piping Systems: Part 2." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93628.
Full textAbstract:
Since there have been several instances of weldment failures in main steam (MS) and hot reheat (HRH) piping systems, most utilities have developed programs to examine their most critical welds. Many utilities select their MS and HRH critical girth welds for examination by consideration of some combination of the ASME B31.1 Code [1] (Code) highest sustained stresses, highest thermal expansion stresses, terminal point locations, and fitting weldments. This paper suggests the use of an alternative life management methodology to prioritize material damage locations based on realistic stresses and applicable damage mechanisms. This methodology is customized to each piping system, considering applicable affects, such as operating history, measured weldment wall thicknesses, observed support anomalies, actual piping thermal displacements, and more realistic time-dependent multiaxial stresses. The high energy piping life consumption (HEPLC) methodology for MS and HRH critical girth welds may be considered as a rational approach to determine critical weldment locations for examinations and to determine appropriate reexamination intervals as a risk-based evaluation technique. The HEPLC methodology has been implemented over the past 15 years to provide more realistic estimates of actual displacements, stresses, and material damage based on the evaluation of field conditions. This HEPLC methodology can be described as having three basic phases: data collection, evaluation, and recommendations. The data collection phase includes obtaining design and post construction piping and supports information. The effects of current piping loads and anomalies are evaluated for potential creep/fatigue damage at the most critical weldments. The top ranked weldments of the HEPLC study are than selected as the highest priority examination locations. The author has completed many HEPLC studies of MS and HRH piping systems. The previous paper (Part 1) provided examples of data collection results and documentation of observed piping system anomalies. This paper will provide examples of evaluation results and recommendations, including a few case histories that have correctly ranked and predicted locations of significant creep/fatigue damage.
2
Zhang, Haoyuan, Lei Zheng, and Lin Cai. "HePNC: Design of physical layer network coding with heterogeneous modulations." In GLOBECOM 2014 - 2014 IEEE Global Communications Conference. IEEE, 2014. http://dx.doi.org/10.1109/glocom.2014.7037213.
Full text
3
Shkolnik, Nikolay, and Alexander C. Shkolnik. "High Efficiency Hybrid Cycle Engine." In ASME 2006 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/icef2005-1221.
Full textAbstract:
A “High Efficiency Hybrid Cycle” (HEHC) thermodynamic cycle is explored. This four-stroke cycle borrows elements from Otto, Diesel, Atkinson, and Rankine cycles. Air is compressed into an isolated combustion chamber, allowing for true isochoric combustion, and extended duration for combustion to proceed until completion. Combustion products expand into a chamber with greater volume than intake. We provide details of a compact HEHC design implementation using rotary pistons and isolated rotating combustion chambers. Two Pistons simultaneously rotate and reciprocate and are held in position by two roller bearings. One Piston performs intake and compression, while the other performs exhaust and expansion. We predict a reduction of energy losses, moving part counts, weight and size over conventional engines.
4
Zhang, Haoyuan, and Lin Cai. "HePNC: A Cross-Layer Design for MIMO Networks with Asymmetric Two-Way Relay Channel." In GLOBECOM 2015 - 2015 IEEE Global Communications Conference. IEEE, 2015. http://dx.doi.org/10.1109/glocom.2015.7417073.
Full text
5
Zhang, Haoyuan, and Lin Cai. "HePNC: A Cross-Layer Design for MIMO Networks with Asymmetric Two-Way Relay Channel." In GLOBECOM 2015 - 2015 IEEE Global Communications Conference. IEEE, 2014. http://dx.doi.org/10.1109/glocom.2014.7417073.
Full text
6
Cohn, Marvin J. "Risk-Based Inspection Applied to Main Steam and Hot Reheat Piping Systems." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26375.
Full textAbstract:
Many utilities select critical welds in their main steam (MS) and hot reheat (HRH) piping systems by considering some combination of design-based stresses, terminal point locations, and fitting weldments. The conventional methodology results in frequent inspections of many low risk areas and the neglect of some high risk areas. This paper discusses the use of a risk-based inspection (RBI) strategy to select the most critical inspection locations, determine appropriate reexamination intervals, and recommend the most important corrective actions for the piping systems. The high energy piping life consumption (HEPLC) strategy applies cost effective RBI principles to enhance inspection programs for MS and HRH piping systems. Using a top-down methodology, this strategy is customized to each piping system, considering applicable effects, such as expected damage mechanisms, previous inspection history, operating history, measured weldment wall thicknesses, observed support anomalies, and actual piping thermal displacements. This information can be used to provide more realistic estimates of actual time-dependent multiaxial stresses. Finally, the life consumption estimates are based on realistic weldment performance factors. Risk is defined as the product of probability and consequence. The HEPLC strategy considers a more quantitative probability assessment methodology as compared to most RBI approaches. Piping stress and life consumption evaluations, considering existing field conditions and inspection results, are enhanced to reduce the uncertainty in the quantitative probability of failure value for each particular location and to determine a more accurate estimate for future inspection intervals. Based on the results of many HEPLC projects, the author has determined that most of the risk (regarding failure of the pressure boundary) in MS and HRH piping systems is associated with a few high priority areas that should be examined at appropriate intervals. The author has performed many studies using RBI principles for MS and HRH piping systems over the past 15 years. This life management strategy for MS and HRH critical welds is a rational approach to determine critical weldment locations for examinations and to determine appropriate reexamination intervals as a risk-based evaluation technique. Both consequence of failure (COF) and likelihood of failure (LOF) are considered in this methodology. This paper also provides a few examples of the application of this methodology to MS and HRH piping systems.
7
Budtz-Joergensen, Carl, Axel Bahnsen, M. M. Madsen, C. Olesen, Per Jonasson, and Herbert W. Schnopper. "High-Energy/Low-Energy Proportional Counter (HEPC/LEPC) detector systems on the SRG." In SPIE's 1994 International Symposium on Optics, Imaging, and Instrumentation, edited by Richard B. Hoover and Arthur B. C. Walker, Jr. SPIE, 1994. http://dx.doi.org/10.1117/12.193172.
Full text
8
Cohn, Marvin J., and Dan Nass. "Creep Life Prediction For High Energy Piping Girth Welds Case History: Cholla, Unit 2." In ASME 2002 Pressure Vessels and Piping Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/pvp2002-1225.
Full textAbstract:
Creep damage of high energy piping (HEP) systems in fossil fuel power plants results from operation at creep range temperatures and stresses over many years. Thermal expansion stresses are typically below the yield stress and gradually relax over time. Consequently, the operating stresses in a piping system are typically below the yield stress and become load controlled. Conventional designs of HEP systems use the American Society of Mechanical Engineers B31.1 Power Piping Code. The Code is a general guideline for piping system design. Utilities typically determine examination sites by performing Code piping stress analyses and selecting locations that include the highest sustained longitudinal stress, highest thermal expansion stress, and terminal points. However, the Code does not address weldment properties, redistribution of thermal stresses and time-dependent life consumption due to material creep degradation. As an alternative, a high energy piping life consumption (HEPLC) methodology was used to predict maximum material damage locations. The methodology was used to prioritize expected creep damage locations, considering applicable affects such as weldment properties, field piping displacements, time-dependent operating stresses, and multiaxial piping stresses. This approach was applied to the main steam piping system at Cholla Unit 2. The locations of highest expected creep damage would not have been selected by a conventional site selection approach. Significant creep damage was found at the locations of maximum expected creep damage using the HEPLC methodology.
9
Cohn, Marvin J. "Life Management of Main Steam and Hot Reheat Piping Systems: Part 1." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93627.
Full textAbstract:
Many utilities choose critical girth welds in their main steam (MS) and hot reheat (HRH) steam piping by consideration of some combination of the ASME B31.1 Code [1] (Code) highest sustained load and thermal expansion stresses, terminal point locations, and fitting weldments subject to stress intensification. As an alternative, a life management methodology is used to prioritize material damage locations based on realistic stresses and applicable damage mechanisms. This methodology is customized to each piping system, considering applicable affects, such as operating history, measured weldment wall thicknesses, observed support anomalies, actual piping thermal displacements, and more realistic time-dependent multiaxial stresses. The life management methodology for MS and HRH critical girth welds may be considered as a rational approach to determine critical weldment locations for examinations and to determine appropriate reexamination intervals as a risk-based evaluation technique. This methodology has been implemented over the past 15 years to provide more realistic estimates of actual displacements, strains, stresses, and material damage based on the evaluation of field conditions. This high energy piping life consumption (HEPLC) methodology can be described as having three basic phases: data collection, evaluation, and recommendations. The data collection phase includes obtaining design and post construction piping and supports information. The effects of current anomalies are evaluated to prioritize critical examination locations. Results of the examinations at the most critical locations are used to determine the degree of material damage at lead-the-fleet locations. The author has performed many HEPLC studies of MS and HRH piping systems. This paper will provide examples of data collection results and documentation of observed piping system anomalies.
10
Cohn, Marvin J. "Comparison of a Life Consumption Analysis to Section III, Subsection NH Design Rules for a Main Steam Girth Weld Creep Crack." In ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-1927.
Full textAbstract:
Creep damage of high energy piping (HEP) systems in fossil fuel power plants results from operation at creep range temperatures and high stresses over many years. Typically, the operating stresses in an HEP piping system are substantially below the yield stress. They tend to be load controlled and time dependent. In spring 1999, Arizona Public Service Company performed an examination of several girth welds of a main steam piping system at Cholla Power Station, Unit 2. A significant creep-related crack was found in a weld after 158,000 operating hours. The American Society of Mechanical Engineers (ASME) Subsection NH methodology was used to evaluate the load controlled stress design rules for nuclear Class 1 components in elevated temperature service as applied to this piping system. A high energy piping life consumption (HEPLC) analysis was performed prior to the examination to select and rank the most critical welds. After obtaining critical information during the outage, the software was also used to estimate the life exhaustion at the most critical weld. A discussion of results for the two approaches is provided in this paper.