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Journal articles on the topic "PTXs"
1
Pazour, G. J., O. A. Sineshchekov, and G. B. Witman. "Mutational analysis of the phototransduction pathway of Chlamydomonas reinhardtii." Journal of Cell Biology 131, no. 2 (October 15, 1995): 427–40. http://dx.doi.org/10.1083/jcb.131.2.427.
Full textAbstract:
Chlamydomonas has two photobehavioral responses, phototaxis and photoshock. Rhodopsin is the photoreceptor for these responses and the signal transduction process involves transmembrane Ca2+ fluxes. This causes transient changes in flagellar beating, ultimately resulting in phototaxis or photoshock. To identify components that make up this signal transduction pathway, we generated nonphototactic strains by insertional mutagenesis. Seven new phototaxis genes were identified (ptx2-ptx8); alleles of six of these are tagged by the transforming DNA and therefore should be easily cloned. To order the mutants in the pathway, we characterized them electrophysiologically, behaviorally, and structurally, ptx5, ptx6, and ptx7 have normal light-induced photoreceptor currents (PRC) and flagellar currents (FC) but their pattern of swimming does not change in the normal manner when the intraflagellar Ca2+ concentration is decreased, suggesting that they have defects in the ability of their axonemes to respond to changes in Ca2+ concentration. ptx2 and ptx8 lack the FC but have normal PRCs, suggesting that they are defective in the flagellar Ca2+ channel or some factor that regulates it. ptx4 mutants have multiple eye-spots. ptx3 mutants are defective in a component essential for phototaxis but bypassed during photoshock; this component appears to be located downstream of the PRC but upstream of the axoneme.
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Kathariya, Rahul, Hansa Jain, Dnyneshwari Gujar, Archana Singh, Himanshu Ajwani, and Devendra Mandhyan. "Pentraxins as Key Disease Markers for Periodontal Diagnosis." Disease Markers 34, no. 3 (2013): 143–51. http://dx.doi.org/10.1155/2013/259273.
Full textAbstract:
Periodontal diseases are characterized by a complex set of biologic interactions between a diverse and dynamic microbial ecosystem and the host’s multifaceted and responsive immune and inflammatory machinery. Such interactions between microbial pathogens and various host response systems play a critical role in the development and progression of periodontal disease via the release of inflammatory and immune mediators. Advances in periodontal disease diagnostic are moving toward methods whereby periodontal risk can be identified and quantified by detecting such inflammatory mediators in its sequential pathophysiology. Pentraxins (PTXs) are classical mediators of inflammation and markers of acute-phase reaction. They are a super family of multifunctional molecules characterized by multimeric structure, divided into “short” PTXs and “long” PTXs. C-reactive protein (CRP) and pentraxin-3 (PTX3) are prototypic molecules of the short and long PTX family, respectively. Evidence suggests that PTXs acts as a non-redundant component of the humoral arm of innate immunity, downstream of, and complementary to, cellular recognition, as well as a tuner of inflammation. CRP is a cheaper biomarker and more readily available in everyday clinical practice compared with other inflammatory markers, on the other hand, PTX3 is believed to be the true independent indicator of disease activity and could have clinical implication in diagnosing the “at site” inflammatory status of the periodontal disease. These pentraxins are sensitive and specific in the diagnosis and prognosis of chronic diseases. Thus the pentraxins could be used as preferred biomarkers in periodontal disease diagnosis.
3
Colmer, Jane A., and Abdul N. Hamood. "Molecular analysis of thePseudomonas aeruginosaregulatory genesptxRandptxS." Canadian Journal of Microbiology 47, no. 9 (September 1, 2001): 820–28. http://dx.doi.org/10.1139/w01-088.
Full textAbstract:
We have previously described two Pseudomonas aeruginosa genes, ptxR, which enhances toxA and pvc ( the pyoverdine chromophore operon) expression, and ptxS, the first gene of the kgu operon for the utilization of 2-ketogluconate by P. aeruginosa. ptxS interferes with the effect of ptxR on toxA expression. In this study, we have utilized DNA hybridization experiments to determine the presence of ptxR and ptxS homologous sequences in several gram-negative bacteria. ptxR homologous sequences were detected in P. aeruginosa strains only, while ptxS homologous sequences were detected in P. aeruginosa, Pseudomonas putida, and Pseudomonas fluorescens. Using Northern blot hybridization experiments and a ptxSlacZ fusion plasmid, we have shown that P. aeruginosa ptxR and ptxS are expressed in P. putida and P. fluorescens. Additional Northern blot hybridization experiments confirmed that ptxS is transcribed in P. putida and P. fluorescens strains that carried no plasmid. The presence of a PtxS homologue in these strains was examined by DNA-gel shift experiments. Specific gel shift bands were detected when the lysates of P. aeruginosa, P. putida, and P. fluorescens were incubated with the ptxS operator site as probe. kgu-hybridizing sequences were detected in P. putida and P. fluorescens. These results suggest that (i) ptxR is present in P. aeruginosa, while ptxS is present in P. aeruginosa, P. putida, and P. fluorescens; (ii) both ptxR and ptxS are expressed in P. putida and P. fluorescens; and (iii) a PtxS homologue may exist in P. putida and P. fluorescens.Key words: Pseudomonas aeruginosa, ptxR, ptxS, DNA hybridization, kgu operon.
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Swanson, Britta L., and Abdul N. Hamood. "Autoregulation of the Pseudomonas aeruginosa Protein PtxS Occurs through a Specific Operator Site within the ptxS Upstream Region." Journal of Bacteriology 182, no. 15 (August 1, 2000): 4366–71. http://dx.doi.org/10.1128/jb.182.15.4366-4371.2000.
Full textAbstract:
ABSTRACT We have previously shown that the Pseudomonas aeruginosa toxA regulatory protein PtxS autoregulates its own synthesis by binding to a 52-bp fragment. The 3′ end of the 52-bp fragment is located 58 bp 5′ of the ptxS translation start site. We have identified a 14-bp palindromic sequence (TGAAACCGGTTTCA) within the 52-bp fragment. In this study, we used site-directed mutagenesis and promoter fusion experiments to determine if PtxS binds specifically to this palindromic sequence and regulatesptxS expression. We have also tried to determine the roles of specific nucleotides within the palindromic sequence in PtxS binding and ptxS expression. Initial promoter fusion experiments confirmed that the 52-bp fragment does not overlap with the region that carries the ptxS promoter activity. PtxS binding was eliminated upon the deletion of the 14-bp palindromic sequence from the 52-bp fragment. In addition, the deletion of the 14-bp sequence caused a significant enhancement in ptxS expression in theP. aeruginosa strain PAO1 and the ptxS isogenic mutant PAO::ptxS. Mutation of specific nucleotides within the 14-bp sequence eliminated, reduced, or had no effect on PtxS binding. However, mutations of several of these nucleotides produced a significant increase in ptxSexpression in both PAO1 and PAO::ptxS. These results suggest that (i) the 14-bp palindromic sequence and specific nucleotides within it play a role in PtxS binding and (ii) deletion of the palindromic sequence or changing of certain nucleotides within it interferes with another mechanism that may regulate ptxSexpression.
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Swanson, Britta L., Jane A. Colmer, and Abdul N. Hamood. "The Pseudomonas aeruginosa Exotoxin A Regulatory Gene, ptxS: Evidence for Negative Autoregulation." Journal of Bacteriology 181, no. 16 (August 15, 1999): 4890–95. http://dx.doi.org/10.1128/jb.181.16.4890-4895.1999.
Full textAbstract:
ABSTRACT We have previously described a Pseudomonas aeruginosagene, ptxR, which enhances exotoxin A production at the transcriptional level. We have also described another gene,ptxS, which is transcribed divergently fromptxR and interferes with the enhancement of exotoxin A synthesis by ptxR. However, the mechanisms through whichptxR and/or ptxS are regulated is not known. In this study, we attempted (by using the DNA gel shift assay) to determine if P. aeruginosa contains a potential regulatory protein that binds specifically to the ptxR orptxS upstream region. In the initial analysis, different-sized gel shift bands were detected when a probe containing the ptxR-ptxS intergenic region was incubated with the lysate of P. aeruginosa PAO1. The strongest binding activity was detected with a smaller fragment that represents theptxS upstream region. Additional deletion analysis localized the binding to a 52-bp fragment immediately upstream ofptxS. The gel shift band was not detected when the 52-bp fragment was incubated with the lysate of the ptxS isogenic mutant PAO1::ptxS. However, the binding band was regenerated when a plasmid carrying ptxS intact was introduced into PAO1::ptxS. In addition, the gel shift band was detected when the 52-bp fragment was incubated with a lysate of Escherichia coli in which ptxS was overexpressed from the T7 promoter. The effect of PtxS onptxS expression was examined by using aptxS-lacZ fusion plasmid. The level of β-galactosidase activity produced by PAO1::ptxS carrying the fusion plasmid was four- to fivefold higher than that produced by PAO1 carrying the same plasmid. Using DNase I footprinting analysis, the binding region was specified to a 20-bp fragment. Within the fragment, a 14-bp palindromic sequence exists that may function as a PtxS binding site. These results suggest that PtxS autoregulates its synthesis by binding to a specific sequence within the ptxSupstream region.
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Westfall, Landon W., A. Marie Luna, Michael San Francisco, Stephen P. Diggle, Kathryn E. Worrall, Paul Williams, Miguel Cámara, and Abdul N. Hamood. "The Pseudomonas aeruginosa global regulator MvaT specifically binds to the ptxS upstream region and enhances ptxS expression." Microbiology 150, no. 11 (November 1, 2004): 3797–806. http://dx.doi.org/10.1099/mic.0.27270-0.
Full textAbstract:
Exotoxin A production in Pseudomonas aeruginosa is regulated positively or negatively by several genes. Two such regulatory genes, ptxR and ptxS, which are divergently transcribed from each other, have been described previously. While computer analysis suggested that the ptxR-ptxS intergenic region contains potential binding sites for several regulatory proteins, the mechanism that regulates the expression of either ptxR or ptxS in P. aeruginosa is not known. The presence of a P. aeruginosa protein complex that specifically binds to a segment within this region was determined. In this study the binding region was localized to a 150 bp fragment of the intergenic region and the proteins that constitute the binding complex were characterized as P. aeruginosa HU and MvaT. Recombinant MvaT was purified as a fusion protein (MAL-MvaT) and shown to specifically bind to the ptxR-ptxS intergenic region. A PAO1 isogenic mutant defective in mvaT, PAOΔmvaT, was constructed and characterized. The lysate of PAOΔmvaT failed to bind to the 150 bp probe. The effect of mvaT on ptxS and ptxR expression was examined using real-time PCR experiments. The expression of ptxS was lower in PAOΔmvaT than in PAO1, but no difference was detected in ptxR expression. These results suggest that MvaT positively regulates ptxS expression by binding specifically to the ptxS upstream region.
7
Alcántara-Rubira, Alex, Víctor Bárcena-Martínez, Maribel Reyes-Paulino, Katherine Medina-Acaro, Lilibeth Valiente-Terrones, Angélica Rodríguez-Velásquez, Rolando Estrada-Jiménez, and Omar Flores-Salmón. "First Report of Okadaic Acid and Pectenotoxins in Individual Cells of Dinophysis and in Scallops Argopecten purpuratus from Perú." Toxins 10, no. 12 (November 23, 2018): 490. http://dx.doi.org/10.3390/toxins10120490.
Full textAbstract:
Causative species of Harmful Algal Bloom (HAB) and toxins in commercially exploited molluscan shellfish species are monitored weekly from four classified shellfish production areas in Perú (three in the north and one in the south). Okadaic acid (OA) and pectenotoxins (PTXs) were detected in hand-picked cells of Dinophysis (D. acuminata-complex and D. caudata) and in scallops (Argopecten purpuratus), the most important commercial bivalve species in Perú. LC-MS analyses revealed two different toxin profiles associated with species of the D. acuminata-complex: (a) one with OA (0.3–8.0 pg cell−1) and PTX2 (1.5–11.1 pg cell−1) and (b) another with only PTX2 which included populations with different toxin cell quota (9.3–9.6 pg cell−1 and 5.8–9.2 pg cell−1). Toxin results suggest the likely presence of two morphotypes of the D. acuminata-complex in the north, and only one of them in the south. Likewise, shellfish toxin analyses revealed the presence of PTX2 in all samples (10.3–34.8 µg kg−1), but OA (7.7–15.2 µg kg−1) only in the northern samples. Toxin levels were below the regulatory limits established for diarrhetic shellfish poisoning (DSP) and PTXs (160 µg OA kg−1) in Perú, in all samples analyzed. This is the first report confirming the presence of OA and PTX in Dinophysis cells and in shellfish from Peruvian coastal waters.
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Cropano, Catrina, Tomaz Mesar, David Turay, David King, Daniel Yeh, Peter Fagenholz, George Velmahos, and Marc A. de Moya. "Pneumothoraces on Computed Tomography Scan: Observation using the 35 Millimeter Rule is Safe." Panamerican Journal of Trauma, Critical Care & Emergency Surgery 4, no. 2 (2015): 48–53. http://dx.doi.org/10.5005/jp-journals-10030-1116.
Full textAbstract:
ABSTRACT Introduction The management of a pneumothorax (PTX) either by observation or with a tube thoracostomy (TT) has long been dictated by practitioner discretion rather than objective criteria. Many physicians elect to routinely place a TT for traumatic PTX, particularly when patients undergo positive pressure ventilation (PPV). Placement of unnecessary TT exposes patients to avoidable morbidity and may prolong hospitalization. Based on prior work establishing a cutoff, we hypothesized that all PTXs ≤35 mm in patients who have no physiologic derangement may be safely observed without TT regardless of the need for PPV. Materials and methods Retrospective review of all patients diagnosed with a PTX between 1/2009 and 2/2013. All PTXs visible on chest computed tomography (CT) were identified. Any patient with an associated significant hemothorax or those patients who were moribund were excluded. All PTXs were measured by measuring the perpendicular distance of the largest air pocket between the chest wall and the mediastinal or pulmonary structure. Management of the PTX was categorized as observation or TT. Observed PTXs were labeled as success or failure with failure defined as enlargement of the PTX or physiologic deterioration, requiring a TT. Results Out of 165 PTXs, 17 (10.3%) measured >35 mm, whereas 148 (89.7%) measured ≤35 mm. Of the 17 > 35 mm, 15 (88.2%) received immediate TT. Of the two PTXs >35 mm which were observed, one received a delayed TT for a pleural effusion (6 days after PTX diagnosis) and one (5.9 %) was safely observed. Of the 148 PTXs which measured ≤35 mm, 10 (6.8%) received immediate TT. Of the 138 remaining PTXs, 129 (93.5%) were safely managed without TT. Six (4.3%) of the PTXs initially observed eventually required TT placement for enlargement of the PTX. Only one of those six had manifested ongoing desaturations prior to TT. The remaining three cases received TT for reasons unrelated to the PTX. Of the 27 PPV cases in the ≤35 mm cohort, none contributed to the six failures. A cutoff measurement of 35 mm demonstrated a negative predictive value (NPV) of 95.7% in its ability to predict successful observation of the PTX with an area under the receiver operating characteristic (ROC) curve of 0.90. Conclusion All PTXs measuring ≤35 mm perpendicular to the chest wall without physiologic derangement may be safely observed independent of the need for mechanical ventilation. How to cite this article Cropano C, Mesar T, Turay D, King D, Yeh D, Fagenholz P, Velmahos G, de Moya MA. Pneumothoraces on Computed Tomography Scan: Observation using the 35 Millimeter Rule is Safe. Panam J Trauma Crit Care Emerg Surg 2015;4(2):48-53.
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Pineda-Molina, E., A. Daddaoua, T. Krell, J. L. Ramos, J. M. García-Ruiz, and J. A. Gavira. "In situX-ray data collection from highly sensitive crystals ofPseudomonas putidaPtxS in complex with DNA." Acta Crystallographica Section F Structural Biology and Crystallization Communications 68, no. 11 (October 30, 2012): 1307–10. http://dx.doi.org/10.1107/s1744309112028540.
Full textAbstract:
Pseudomonas putidaPtxS is a member of the LacI protein family of transcriptional regulators involved in glucose metabolism. All genes involved in this pathway are clustered into two operons,kguandgad. PtxS controls the expression of thekguandgadoperons as well as its own transcription. The PtxS operator is a perfect palindrome, 5′-TGAAACCGGTTTCA-3′, which is present in all three promoters. Crystallization of native PtxS failed, and PtxS–DNA crystals were finally produced by the counter-diffusion technique. A portion of the capillary used for crystal growth was attached to the end of a SPINE standard cap and directly flash-cooled in liquid nitrogen for diffraction tests. A full data set was collected with a beam size of 10 × 10 µm. The crystal belonged to the trigonal space groupP3, with unit-cell parametersa=b= 213.71,c = 71.57 Å. Only unhandled crystals grown in capillaries of 0.1 mm inner diameter diffracted X-rays to 1.92 Å resolution.
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Daddaoua, Abdelali, Tino Krell, Carlos Alfonso, Bertrand Morel, and Juan-Luis Ramos. "Compartmentalized Glucose Metabolism in Pseudomonas putida Is Controlled by the PtxS Repressor." Journal of Bacteriology 192, no. 17 (June 25, 2010): 4357–66. http://dx.doi.org/10.1128/jb.00520-10.
Full textAbstract:
ABSTRACT Metabolic flux analysis revealed that in Pseudomonas putida KT2440 about 50% of glucose taken up by the cells is channeled through the 2-ketogluconate peripheral pathway. This pathway is characterized by being compartmentalized in the cells. In fact, initial metabolism of glucose to 2-ketogluconate takes place in the periplasm through a set of reactions catalyzed by glucose dehydrogenase and gluconate dehydrogenase to yield 2-ketogluconate. This metabolite is subsequently transported to the cytoplasm, where two reactions are carried out, giving rise to 6-phosphogluconate, which enters the Entner-Doudoroff pathway. The genes for the periplasmic and cytoplasmic set of reactions are clustered in the host chromosome and grouped within two independent operons that are under the control of the PtxS regulator, which also modulates its own synthesis. Here, we show that although the two catabolic operons are induced in vivo by glucose, ketogluconate, and 2-ketogluconate, in vitro we found that only 2-ketogluconate binds to the regulator with an apparent KD (equilibrium dissociation constant) of 15 μM, as determined using isothermal titration calorimetry assays. PtxS is made of two domains, a helix-turn-helix DNA-binding domain located at the N terminus and a C-terminal domain that binds the effector. Differential scanning calorimetry assays revealed that PtxS unfolds via two events characterized by melting points of 48.1°C and 57.6°C and that, in the presence of 2-ketogluconate, the unfolding of the effector binding domain occurs at a higher temperature, providing further evidence for 2-ketogluconate-PtxS interactions. Purified PtxS is a dimer that binds to the target promoters with affinities in the range of 1 to 3 μM. Footprint analysis revealed that PtxS binds to an almost perfect palindrome that is present within the three promoters and whose consensus sequence is 5′-TGAAACCGGTTTCA-3′. This palindrome overlaps with the RNA polymerase binding site.
Dissertations / Theses on the topic "PTXs"
1
Burgess, Vanessa Anne, and n/a. "Toxicology Investigations With The Pectenotoxin-2 Seco Acids." Griffith University. School of Public Health, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030905.090222.
Full textAbstract:
Pectenotoxins (PTXs) are a group of large cyclic polyether compounds associated with diarrhetic shellfish poisoning (DSP) as they are often found in combination with other DSPs such as okadaic acid (OA) and dinophysis toxins (DTXs) in shellfish. Although classified and regulated with the DSPs, there is debate over whether these toxins should be classified with DSP toxins. To date, ten different analogues of PTXs have been identified from shellfish and algae, and of these, the pectenotoxin-2 seco acids (PTX2-SAs) are of particular interest as they have previously been implicated in a shellfish poisoning incident in Australia, but relatively little was known of their toxicology. One such incident occurred in December 1997, when approximately 200 people were reported with severe diarrhoetic shellfish poisoning in Northern New South Wales (NSW). Analysis of the shellfish associated with this incident revealed relatively high PTX2-SA concentrations (approx. 300 micrograms/kg shellfish meat), with only trace amounts of pectenotoxin-2 (PTX2) and OA. Following this incident, PTX2-SAs were considered a health threat and guidelines were implemented in the absence of toxicological data, which has caused a great economic burden to shellfish industries around the globe, in particular to Australia, New Zealand and Ireland. Such regulation created in the absence of scientific data demonstrated the need to determine the toxicology of PTX2-SAs in commercial shellfish. Thus a comprehensive study on the toxicology and possible health implications of the PTX2-SAs in Australian shellfish was conducted. PTX2-SAs were isolated in different batches from shellfish (pipis, oysters and mussels) and from algal bloom samples of Dinophysis caudata. Toxin extraction was conducted with several purification stages and chemical analysis was performed with high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). The chemical stability of the PTX2-SAs was investigated to ensure consistency of doses between toxicology experiments. Acute dosing studies with mice were then performed and included toxicopathology investigations with light microscopy and electron microscopy, in addition to toxin distribution studies and investigation of in vivo lipid peroxidation. In vitro studies with HepG2 cells included cytotoxicity assays, cell cycle investigations using flow cytometry and gene expression profiling of cells exposed to PTX2-SAs employing cDNA microarray technology. Acute pathology studies demonstrated that the PTX2-SAs do not cause the characteristic symptoms or lesions associated with DSP toxins. No diarrhoea was observed at any dose level in mice and no deaths occurred up to the maximum dosing level of 1.6mg/kg PTX2-SA. Only one batch of PTX2-SA extract produced toxic lesions characteristic of a DSP toxin (batch 1-pilot study) but after follow up studies, it was determined that this first batch of shellfish most likely contained an additional unidentified shellfish toxin or contaminant that co-extracted with PTX2-SAs during toxin isolation and purification procedures. This finding highlighted the importance of supporting the inclusion of the mice bioassay in procedures for shellfish toxin testing to enable detection of new toxins, and also highlighted the importance of toxin purification for toxicology studies. A significant rise in malondialdehyde excretion was observed within 24 hours of dosing mice, indicating that the PTX2-SAs may cause damage by lipid peroxidation in vivo. In vitro studies showed HepG2 cells to have cell cycle and gene expression changes within 24 hours of a dose of 800ng/mL PTX2-SAs. Cell cycle arrest was observed at the G2/M checkpoint and gene expression changes included alterations in genes involved in cell cycle control, lipid metabolism and transport, lipid genesis and trace metal transport. Many genes involved in DNA repair processes were moderated at the 24 hour point, but as no apoptosis was observed up to 72 hours post dosing it is a promising indication that any DNA damage that may have been caused by the administration of PTX2-SAs was not lethal, and was able to be repaired. In light of the information provided by toxicology investigations in this PhD, with particular reference to evidence of in vivo lipid peroxidation by raised levels of MDA in mouse urine, and changes in cell cycle distribution and gene expression in a cultured human cell line, it is concluded that there is potential for these toxins to induce biological changes in mammalian cells in vivo and in vitro, and hence potential for PTX2-SAs to cause health effects in humans. During the course of this three-year study, developments in techniques for shellfish toxin identification within our laboratories have revealed that the shellfish responsible for the 1997 NSW poisoning incident contained significant concentrations of okadaic acid acyl esters that were not detected at the time of the NSW incident. Although reportedly less toxic than okadaic acid itself, the OA ester concentrations present may have been sufficient to cause the observed symptoms. It is also theorized that these esters could be hydrolyzed in the human gastro-intestinal tract to release okadaic acid. In the light of this new evidence and with no pathology lesions or symptoms of diarrhoea being observed in PTX2-SA dosing studies with mice, we now believe these OA acyl esters to be the causative agent in the 1997 NSW DSP incident and not the PTX2-SAs. Nothing is currently known of the chronic toxicology of PTX2-SAs and thus their potential implications to public health in the long term cannot determined. The toxicology investigations in this thesis were acute studies, and it has not been established if the observed changes could be repaired or returned within normal limits without the manifestation of illness or disease occurring. Utilizing the acute toxicology information in this thesis, a health risk assessment for consumption of PTX2-SA contaminated shellfish was performed. This risk assessment, employing numerous safety factors essential for an incomplete data set, produced guideline values that are lower than the current recommend concentrations. To date, there has been no solid evidence that PTX2-SAs cause illness in humans all documented incidents involving the PTX2-SAs have also included other DSP contaminants that are known to cause human illness. Pathology has not unequivocally been demonstrated in animal studies and thus, in consideration of the epidemiological evidence, PTX2-SAs cannot be considered as high a risk to public health as was previously thought. For the reasons discussed above, and weighing up risk-benefit considerations of the economic burden the current guideline values are causing to shellfish industries around the globe, it is recommended that levels of PTX2-SAs be monitored in recognition of the precautionary principle, but no longer regulated as tightly with other DSPs until such a time that toxicological or epidemiological evidence can prove that the PTX2-SAs are a DSP and are a more considerable threat to human health than has been indicated by toxicology studies in this thesis. This study has produced a substantial amount of acute toxicology data and has provided a good basis for future chronic toxicology investigations with the PTX2-SAs for regulatory purposes.
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Burgess, Vanessa Anne. "Toxicology Investigations With The Pectenotoxin-2 Seco Acids." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/365382.
Full textAbstract:
Pectenotoxins (PTXs) are a group of large cyclic polyether compounds associated with diarrhetic shellfish poisoning (DSP) as they are often found in combination with other DSPs such as okadaic acid (OA) and dinophysis toxins (DTXs) in shellfish. Although classified and regulated with the DSPs, there is debate over whether these toxins should be classified with DSP toxins. To date, ten different analogues of PTXs have been identified from shellfish and algae, and of these, the pectenotoxin-2 seco acids (PTX2-SAs) are of particular interest as they have previously been implicated in a shellfish poisoning incident in Australia, but relatively little was known of their toxicology. One such incident occurred in December 1997, when approximately 200 people were reported with severe diarrhoetic shellfish poisoning in Northern New South Wales (NSW). Analysis of the shellfish associated with this incident revealed relatively high PTX2-SA concentrations (approx. 300 micrograms/kg shellfish meat), with only trace amounts of pectenotoxin-2 (PTX2) and OA. Following this incident, PTX2-SAs were considered a health threat and guidelines were implemented in the absence of toxicological data, which has caused a great economic burden to shellfish industries around the globe, in particular to Australia, New Zealand and Ireland. Such regulation created in the absence of scientific data demonstrated the need to determine the toxicology of PTX2-SAs in commercial shellfish. Thus a comprehensive study on the toxicology and possible health implications of the PTX2-SAs in Australian shellfish was conducted. PTX2-SAs were isolated in different batches from shellfish (pipis, oysters and mussels) and from algal bloom samples of Dinophysis caudata. Toxin extraction was conducted with several purification stages and chemical analysis was performed with high-performance liquid chromatography coupled to a tandem mass spectrometer (HPLC-MS/MS). The chemical stability of the PTX2-SAs was investigated to ensure consistency of doses between toxicology experiments. Acute dosing studies with mice were then performed and included toxicopathology investigations with light microscopy and electron microscopy, in addition to toxin distribution studies and investigation of in vivo lipid peroxidation. In vitro studies with HepG2 cells included cytotoxicity assays, cell cycle investigations using flow cytometry and gene expression profiling of cells exposed to PTX2-SAs employing cDNA microarray technology. Acute pathology studies demonstrated that the PTX2-SAs do not cause the characteristic symptoms or lesions associated with DSP toxins. No diarrhoea was observed at any dose level in mice and no deaths occurred up to the maximum dosing level of 1.6mg/kg PTX2-SA. Only one batch of PTX2-SA extract produced toxic lesions characteristic of a DSP toxin (batch 1-pilot study) but after follow up studies, it was determined that this first batch of shellfish most likely contained an additional unidentified shellfish toxin or contaminant that co-extracted with PTX2-SAs during toxin isolation and purification procedures. This finding highlighted the importance of supporting the inclusion of the mice bioassay in procedures for shellfish toxin testing to enable detection of new toxins, and also highlighted the importance of toxin purification for toxicology studies. A significant rise in malondialdehyde excretion was observed within 24 hours of dosing mice, indicating that the PTX2-SAs may cause damage by lipid peroxidation in vivo. In vitro studies showed HepG2 cells to have cell cycle and gene expression changes within 24 hours of a dose of 800ng/mL PTX2-SAs. Cell cycle arrest was observed at the G2/M checkpoint and gene expression changes included alterations in genes involved in cell cycle control, lipid metabolism and transport, lipid genesis and trace metal transport. Many genes involved in DNA repair processes were moderated at the 24 hour point, but as no apoptosis was observed up to 72 hours post dosing it is a promising indication that any DNA damage that may have been caused by the administration of PTX2-SAs was not lethal, and was able to be repaired. In light of the information provided by toxicology investigations in this PhD, with particular reference to evidence of in vivo lipid peroxidation by raised levels of MDA in mouse urine, and changes in cell cycle distribution and gene expression in a cultured human cell line, it is concluded that there is potential for these toxins to induce biological changes in mammalian cells in vivo and in vitro, and hence potential for PTX2-SAs to cause health effects in humans. During the course of this three-year study, developments in techniques for shellfish toxin identification within our laboratories have revealed that the shellfish responsible for the 1997 NSW poisoning incident contained significant concentrations of okadaic acid acyl esters that were not detected at the time of the NSW incident. Although reportedly less toxic than okadaic acid itself, the OA ester concentrations present may have been sufficient to cause the observed symptoms. It is also theorized that these esters could be hydrolyzed in the human gastro-intestinal tract to release okadaic acid. In the light of this new evidence and with no pathology lesions or symptoms of diarrhoea being observed in PTX2-SA dosing studies with mice, we now believe these OA acyl esters to be the causative agent in the 1997 NSW DSP incident and not the PTX2-SAs. Nothing is currently known of the chronic toxicology of PTX2-SAs and thus their potential implications to public health in the long term cannot determined. The toxicology investigations in this thesis were acute studies, and it has not been established if the observed changes could be repaired or returned within normal limits without the manifestation of illness or disease occurring. Utilizing the acute toxicology information in this thesis, a health risk assessment for consumption of PTX2-SA contaminated shellfish was performed. This risk assessment, employing numerous safety factors essential for an incomplete data set, produced guideline values that are lower than the current recommend concentrations. To date, there has been no solid evidence that PTX2-SAs cause illness in humans – all documented incidents involving the PTX2-SAs have also included other DSP contaminants that are known to cause human illness. Pathology has not unequivocally been demonstrated in animal studies and thus, in consideration of the epidemiological evidence, PTX2-SAs cannot be considered as high a risk to public health as was previously thought. For the reasons discussed above, and weighing up risk-benefit considerations of the economic burden the current guideline values are causing to shellfish industries around the globe, it is recommended that levels of PTX2-SAs be monitored in recognition of the precautionary principle, but no longer regulated as tightly with other DSPs until such a time that toxicological or epidemiological evidence can prove that the PTX2-SAs are a DSP and are a more considerable threat to human health than has been indicated by toxicology studies in this thesis. This study has produced a substantial amount of acute toxicology data and has provided a good basis for future chronic toxicology investigations with the PTX2-SAs for regulatory purposes.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Public Health
Faculty of Health Sciences
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Rodriguez, Grande Beatriz. "The role of PTX3 in brain inflammation and repair." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/the-role-of-ptx3-in-brain-inflammation-and-repair(b80f9c46-f81b-44a0-af27-efc932a6bd38).html.
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Pentraxin 3 (PTX3) is an acute phase protein which regulates peripheral inflammationand it has been suggested to have neuroprotective properties. Inflammation iscommonly associated with poor outcome during diverse central nervous system (CNS)disorders, but the role of PTX3 in brain inflammation is completely unknown. Westudied the role of PTX3 in brain inflammation and repair after stroke, a CNS disorderwhich is the third cause of death worldwide. To induce ischaemic stroke, we used themiddle cerebral artery occlusion (MCAo) model and found that the pro-inflammatorycytokine interleukin (IL)-1 was the inducer of PTX3 expression in the brain. Theanalysis of markers of inflammation and repair up to 14 days after MCAo in wild typeand PTX3 knockout (KO) mice revealed that, in general, lack of PTX3 has a negativeeffect on recovery after MCAo. PTX3 KO mice had delayed oedema resolution,defective glial scar, impaired microglial proliferation and reduced angiogenesis andneurogenesis. Therefore, PTX3 emerges as a target for stroke recovery and possiblyother CNS inflammatory diseases. PTX3 was, however, not involved in remoteneurodegeneration in the substantia nigra (SN) (an area of the brain remote butconnected with the area affected by the stroke), but we observed that remoteinflammation preceded remote neuronal death in the SN. Therefore, prevention ofremote inflammation may help prevent remote neurodegeneration in the SN afterstroke. This could have long term implications in SN neurodegeneration, which is akey pathological feature of Parkinson´s disease.
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Izuogu, Ginikachukwu Osagie. "Mechanisms and impact of Post-transcriptional Exon Shuffling (PTES)." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3738.
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Most eukaryotic genes undergo splicing to remove introns and join exons sequentially to produce protein-coding or non-coding transcripts. Post-transcriptional Exon Shuffling (PTES) describes a new class of RNA molecules, characterized by exon order different from the underlying genomic context. PTES can result in linear and circular RNA (circRNA) molecules and enhance the complexity of transcriptomes. Prior to my studies, I developed PTESFinder, a computational tool for PTES identification from high-throughput RNAseq data. As various sources of artefacts (including pseudogenes, template-switching and others) can confound PTES identification, I first assessed the effectiveness of filters within PTESFinder devised to systematically exclude artefacts. When compared to 4 published methods, PTESFinder achieves the highest specificity (~0.99) and comparable sensitivity (~0.85). To define sub-cellular distribution of PTES, I performed in silico analyses of data from various cellular compartments and revealed diverse populations of PTES in nuclei and enrichment in cytosol of various cell lines. Identification of PTES from chromatin-associated RNAseq data and an assessment of co-transcriptional splicing, established that PTES may occur during transcription. To assess if PTES contribute to the proteome, I analyzed sucrose-gradient fractionated data from HEK293, treated with arsenite to induce translational arrest and dislodge ribosomes. My results showed no effect of arsenite treatment on ribosome occupancy within PTES transcripts, indicating that these transcripts are not generally bound by polysomes and do not contribute to the proteome. To investigate the impact of differential degradation on expression levels of linear and circRNAs, I analyzed the PTES population within RNAseq data of anucleate cells and established that most PTES transcripts are circular and are enriched in platelets 17-to-188-fold relative to nucleated tissues. For some genes, only reads from circRNA exons were detectable, suggesting that platelets have lost >90% of their progenitor mRNAs, consistent with timedependent degradation of platelets transcriptomes. However, some circRNAs exhibit read density patterns suggestive of miRNA induced degradation. Finally, a linear PTES from RMST locus has been implicated in pluripotency maintenance using limited RNAseq data from human embryonic stem cells (hESC). To identify other PTES transcripts with similar expression patterns, I analyzed RNAseq data from H9 ESC differentiation series. Statistical analyses of PTES transcripts identified during cellular differentiation established that PTES expression changes track with that of cognate linear transcripts and accumulate upon differentiation. Contrary to previous reports, the dominant transcript from RMST is circular and increases in abundance during differentiation. Functional Abstract iii analyses demonstrating the role of RMST in pluripotency maintenance had targeted exons within the predicted circRNA, suggesting previously unreported functional relevance for circRNAs.
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Slusher, Aaron L. "COUNTERREGULATORY EFFECTS OF PTX3 ON INFLAMMATION AND CELLULAR AGING." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5287.
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Pentraxin 3 (PTX3) is a vital regulator of innate immune function that has been shown to counterregulate pro-inflammatory signaling and protect against the development of cardiovascular disease (CVD). Less is known about how PTX3 may mitigate against CVD risk by regulating the pro-inflammatory response at the cellular level. Therefore, this dissertation details four manuscripts which aimed to examine the capacity of PTX3 to regulate the innate immune response of peripheral blood mononuclear cells (PBMCs) isolated from healthy adults. Manuscript 1 examined the capacity of PTX3 to alter the inflammatory milieu following in vitro stimulation of isolated PBMCs with the pro-inflammatory lipid palmitate. In addition, Manuscript 2 sought to examine how participation in acute exercise, a powerful anti-inflammatory behavior that reduces CVD risk, alters the inflammatory phenotype and response of mononuclear cells following ex vivo stimulation with lipopolysaccharide (LPS). Manuscript 3 aimed to further elucidate the potential impact of cardiorespiratory fitness on the capacity of PTX3 to stimulate an innate immune response prior to and immediately following acute exercise in aerobically trained and untrained individuals. Finally, Manuscript 4 investigated the impact of healthy aging on plasma PTX3 concentrations and its relationship with telomere length in middle-aged compared to young adults. The capacity of isolated PBMCs to express a key cellular mechanism involved in maintaining longer telomere lengths, human telomerase reverse transcriptase (hTERT), following cellular stimulation with LPS, PTX3, and PTX3+LPS was also examined to address a mechanism that might explain how persistent exposure of circulating immune cells to the age-related pro-inflammatory milieu contributes to the shortening of telomere lengths.
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Harvey, Thomas Grierson. "Nonlinear optics of the polydiacetylene pTS." Thesis, Heriot-Watt University, 1991. http://hdl.handle.net/10399/874.
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Oliveira, Mirian Maria de. "O SONHO DA MORADIA DIGNA – PROGRAMA MINHA CASA MINHA VIDA - ENTIDADES GOIÂNIA DE 2009 A 2015." Pontifícia Universidade Católica de Goiás, 2017. http://tede2.pucgoias.edu.br:8080/handle/tede/3819.
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This paper analyzes the Housing Policy in Brazil, in particular Social Interest Housing, focusing on the My House My Life Entities Program in the city of Goiânia from 2009 to 2015. How was the work of the social worker performed in the Technical Work Projects (PTTS) of the Harmonia, Jardim Botânico I and Eldorado Oeste IV Housing Settlements, built by Associations attached to Movements of Housing Movements of the State of Goiás. Families moving to their homes begin to face problems such as distance, lack of Public equipment , security and others. The struggle of entities seeking to provide decent housing for the homeless has been working according to the criteria required by the Minha Casa Minha Vida - Entities Program (PMCMV-E)
Este trabalho analisa a Política de Habitação no Brasil em especial a Habitação de Interesse Social, com foco no Programa Minha Casa Minha Vida Entidades na cidade de Goiânia nos anos de 2009 á 2015. Como foi realizado o trabalho do assistente social nos Projetos de Trabalho Técnico Social (PTTS) dos Conjuntos Habitacionais Harmonia, Jardim Botânico I e Eldorado Oeste IV construídos por Associações ligadas a Entidades dos Movimentos de Moradia do Estado de Goiás. As famílias ao mudarem para suas casas,começam a enfrentar problemas como a distância, a falta de equipamentos públicos, segurança e outros. A luta das entidades em busca de propiciar moradia digna aos sem teto, tem trabalhado de acordo com os critérios exigidos pelo Programa Minha Casa Minha Vida – Entidades (PMCMV-E).
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Tremblay, Jacques. "Mécanisme d'action de PTX1, un facteur de transcription à homéodomaine." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq43040.pdf.
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Mishra, Gaurav. "Development of Person-Person Network and Interacting PTTS in EpiSimdemics." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64160.
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Communications over social media, telephone, email, text etc have emerged as an integral part of modern society and they are popularly used for the expression of anger, anxiety, fear, agitation and opinion by the people. People's social interaction tend to increase dramatically during periods of epidemics, protest and calamities. Therefore, above mentioned communication channels plays an important role in the spread of infectious phenomenon, like rumors, fads and effects. These infectious phenomena alters people's behavior during disease epidemic [1][2].
Social contact networks and epidemics co-evolve [1][2]. The spread of a disease influences people's behavior which in turn changes their social contact network, thereby altering the disease spread itself. As a result, there is a need for modeling the spread of these infectious phenomena that lead to changes in behavior. Their propagation among population primarily depends on the social contact network. The nature of social contagion spread is very similar to the spread of any infectious disease as they are contagious in nature. To spread contagious disease requires direct exposure to an infectious agent, whereas social contagions can be spread using various communications media like social networking forums, phones, emails and tweets.
EpiSimdemics is an individual-based modeling environment. It uses a people-location bipartite graph as the underlying network [3]. In its current form, EpiSimdemics requires two people to interact at a location to model simulations. Thus, it cannot simulate the spread of social contagions that do not necessarily require the meeting of two agents at a location.
We enhance EpiSimdemics by incorporating Person-Person network, which can model communications between people that are not contact based such as communications over email, phone, text and tweet. This Person-Person network is used to model effects (social contagion) which induce behavioral changes in population and thus impacting the disease spread. The disease spread is modeled on Person-Location network. This leads to the scenario of two interacting networks: Person-Person network modeling social contagion and Person-Location modeling disease. Theoretically, there can be multiple such networks modeling various interacting phenomena.
We demonstrate the usefulness of this network by modeling and simulating two interacting PTTSs (probabilistic timed transition systems). To model disease epidemics, we have defined Disease Model and to model effects (social contagion), we have defined Fear Model. We show how these models influence each other by performing simulations on EpiSimdemics with interacting Disease and Fear Model. Therefore a model that does not include the affect adaptations on disease epidemics and vice-versa, fails to reflect the actual behavior of a society during disease epidemic spread. The addition of Person-Person network to EpiSimdemics will allow for a better understanding of the affect adaptions, which can include behavior changes in society during an epidemic outbreak. This would lead to effective interventions and help to better understand the dynamics of disease epidemic.Master of Science
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Padrão, Ana Isabel Martins Novais. "Estudo das PTMs do citocromo c cardíaco: efeitos do envelhecimento." Master's thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/3126.
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Mestrado em Métodos BiomolecularesOs mecanismos celulares e bioquímicos subjacentes à disfunção cardíaca associada ao envelhecimento encontram-se pouco esclarecidos e, menos compreendido é o papel do estilo de vida neste processo. No sentido de avaliar a influência do estilo de vida ao longo da vida na potencial perda de funcionalidade das proteínas cardíacas, em particular do citocromo c, utilizaram-se ratinhos C57BL/6 machos que foram sujeitos a um protocolo experimental para simular o envelhecimento sedentário e activo. Os animais foram depois sacrificados, isolaram-se as mitocôndrias do coração e procedeu-se à análise de vários parâmetros bioquímicos com o intuito de (i) avaliar a funcionalidade da cadeia respiratória mitocondrial, (ii) identificar as proteínas susceptíveis à carbonilação e/ou nitração, (iii) caracterizar as PTMs do citocromo c de coração. Os resultados obtidos sugerem a existência de uma relação entre a perda de funcionalidade mitocondrial associada ao envelhecimento e o aumento do teor de proteínas carboniladas e/ou nitradas. Como proteínas alvo destas modificações pós-traducionais (PTMs) foram identificadas várias subunidades dos complexos da fosforilação oxidativa. Pela sua importância neste sistema metabólico, analisou-se mais exaustivamente a susceptibilidade do citocromo c a PTMs resultantes de processos oxidativos e de que forma o estilo de vida regula este processo. Apesar de se ter verificado um aumento da expressão do citocromo c com o envelhecimento, o número e o tipo de PTMs identificadas por LC-MS/MS não seguiu a mesma tendência. Efectivamente, identificou-se um maior número de PTMs no citocromo c do homogeneizado total dos ratinhos jovens (12 PTMs) do que nos ratinhos velhos. Considerando o efeito do estilo de vida, verificou-se a existência nos animais activos de um maior número de resíduos de aminoácidos modificados (10 PTMs) do que nos sedentários (6 PTMs). Curiosamente, a oxidação da Met65 foi a única modificação oxidativa identificada no citocromo c da fracção mitocondrial, tendo sido observada nos ratinhos velhos sedentários. ABSTRACT: Cellular and biochemical mechanisms underlying the age-related cardiac dysfunction are not fully understood and, even less clarified is the influence of lifestyle in this process. In order to evaluate the role of lifelong lifestyle in the mitochondrial plasticity and in the potential functionality loss of cardiac proteins, in particular cytochrome c, to post-translational modifications (PTMs), C57BL/6 male mice were subjected to an experimental protocol simulating sedentary and active aging. After animal sacrifice, mitochondria from cardiac muscle were isolated and several biochemical parameters were measured (i) to evaluate the mitochondrial respiratory chain functionality, (ii) to identify the susceptible proteins to carbonylation and/or nitration, (iii) to characterize the PTMs of cardiac cytochrome c. The results suggest a link between the age-related decrease in mitochondrial functionality and the higher susceptibility of cardiac muscle proteins to oxidative damage. Indeed, we observed a significant increase in the content of carbonylated and/or nitrated proteins in old mice, being the oxidative phosphorylation subunits the most affected. Given the importance of cytochrome c as the final mobile electron carrier in this metabolic process, its susceptibility to PTMs induced by oxidative stress was characterized more exhaustively. Despite the age-induced upregulation of cytochrome c, the number of oxidative PTMs identified by LC-MS/MS was not increased. Indeed, a higher number of PTMs was identified in citochrome c from young mice total homogenate (12 PTMs) compared to old mice. Regarding the effect of lifestyle, old active mice presented more PTMs (10 PTMs) than their sedentary counterparts (6 PTMs). Interestingly, the Met65 oxidation was the only PTM identified in mitochondrial cytochrome c and only in old sedentary mice.
Books on the topic "PTXs"
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Millar, Alan. British PTEs. London: I. Allan, 1985.
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Municipals and PTEs. London: Ian Allan, 1985.
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Corasolla Carregari, Victor, ed. Understanding PTMs in Neurodegenerative Diseases. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-05460-0.
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Wirosuhardjo, Kartomo. PTS sayang, PTS perlu ditimang: Perguruan tinggi swasta dalam sorotan. Jakarta: PT Elex Media Komputindo, 2015.
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M, Conner LeAnne, and Lorenz Gregory F, eds. Kinesiology foundations for OTAs and PTAs. Australia: Thomson Delmar Learning, 2005.
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Böhm, Karsten. EMDR in der Psychotherapie der PTBS. Berlin, Heidelberg: Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-60338-3.
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Physical therapy clinical handbook for PTAs. 2nd ed. Burlington, MA: Jones & Bartlett Learning, 2012.
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Böhm, Karsten. EMDR in der Psychotherapie der PTBS. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-47893-6.
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Soemarno, A. Pengembangan PTS sebagai kekuatan nasional. [Jakarta]: Departemen Pertahanan Keamanan RI, Lembaga Ketahanan Nasional, 1997.
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Stiftung, Papiertechnische. 50 Jahre PTS, 1951-2001. Heusenstamm, Germany: P. Keppler, 2001.
Find full textBook chapters on the topic "PTXs"
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Parente, Raffaella, Barbara Bottazzi, Alberto Mantovani, and Antonio Inforzato. "PTX3." In Encyclopedia of Signaling Molecules, 4316–23. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_101746.
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Parente, Raffaella, Barbara Bottazzi, Alberto Mantovani, and Antonio Inforzato. "PTX3." In Encyclopedia of Signaling Molecules, 1–8. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4614-6438-9_101746-1.
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Msangi, Gaspar, and Kenneth M. Peters. "Neuromodulation: PTNS." In Minimally Invasive Therapy for Urinary Incontinence and Pelvic Organ Prolapse, 171–76. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-0008-4_14.
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Maercker, A. "Komplexe PTBS." In Traumafolgestörungen, 47–60. Berlin, Heidelberg: Springer Berlin Heidelberg, 2019. http://dx.doi.org/10.1007/978-3-662-58470-5_3.
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Villars, P., K. Cenzual, R. Gladyshevskii, O. Shcherban, V. Dubenskyy, V. Kuprysyuk, I. Savysyuk, and R. Zaremba. "PtS." In Landolt-Börnstein - Group III Condensed Matter, 118. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-22847-6_68.
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van Lieshout, Trix, and Ron van Deth. "Posttraumatische-stressstoornis (PTSS)." In Pedagogische adviezen voor speciale kinderen, 119–42. Houten: Bohn Stafleu van Loghum, 2018. http://dx.doi.org/10.1007/978-90-368-1995-4_6.
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Soedirman, J. R., G. Brouwer, and S. Denen. "Posttraumatische stressstoornis (ptss)." In Verpleegkundig Vademecum, 575–82. Houten: Bohn Stafleu van Loghum, 2008. http://dx.doi.org/10.1007/978-90-313-7326-0_109.
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Soedirman, J. R., and G. Brouwer. "Posttraumatische stressstoornis (PTSS)." In Psychiatrie, 76–93. Houten: Bohn Stafleu van Loghum, 2009. http://dx.doi.org/10.1007/978-90-313-7552-3_6.
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Pausch, Markus J., and Sven J. Matten. "Symptome der PTBS." In Trauma und Traumafolgestörung, 27–52. Wiesbaden: Springer Fachmedien Wiesbaden, 2017. http://dx.doi.org/10.1007/978-3-658-17886-4_4.
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Lindauer, Ramón. "Diagnostiek van PTSS." In CAPS-CA DSM-5 – handleiding, 15–17. Houten: Bohn Stafleu van Loghum, 2019. http://dx.doi.org/10.1007/978-90-368-2346-3_3.
Full textConference papers on the topic "PTXs"
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Qian, Guian, and Markus Niffenegger. "Investigation on Constraint Effect of a Reactor Pressure Vessel Subjected to Pressurized Thermal Shocks." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-98161.
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The integrity of a reactor pressure vessel (RPV) related to pressurized thermal shocks (PTSs) has been extensively studied. This paper introduces the method of using fracture mechanics for the integrity analysis of a RPV subjected to PTS transients. A 3-D finite element (FE) model is used to perform thermal and fracture mechanics analyses by considering both elastic and elastic-plastic material models. The results show that the linear elastic analysis leads to a more conservative result than the elastic-plastic analysis. The variation of the T-stress and Q-stress (crack tip constraint loss) of a surface crack in a RPV subjected to PTSs is studied. A shallow crack is assumed in the RPV and the corresponding constraint effect on fracture toughness of the material is quantified by the K-T method. The safety margin of the RPV is larger based on the K-T approach than only based on the K approach. The J-Q method with the modified boundary layer formulation (MBL) is used for the crack tip constraint analysis by considering elastic-plastic material properties. For all transient times, the real stress is lower than that calculated from small scale yielding (SSY) due to the loss of crack tip constraint.
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Qian, Guian, V. F. González-Albuixech, Markus Niffenegger, and Medhat Sharabi. "Probabilistic Pressurized Thermal Shocks Analysis for a Reactor Pressure Vessel by Considering Plume Effect." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45963.
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The inner surface of a reactor pressure vessel (RPV) is assumed to be subjected to pressurized thermal shocks (PTSs) caused by the downstream of emergency cooling water. The downstream is not homogeneous but typically in a plume shape coming from the inlet nozzles. In this paper, both deterministic and probabilistic methods are used to assess the integrity of a model RPV subjected to PTS. The FAVOR code is used to calculate the probabilities for crack initiation and failure of the RPV considering crack distributions based on cracks observed in the Shoreham and PVRUF RPVs. The study shows that peak KI of the cracks inside the plume increases about 33% compared with that outside. The conditional probability inside the plume is more than eight orders of magnitude higher than outside the plume. In order to be conservative, it is necessary to consider the plume effect in the integrity assessment.
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"PTES 2018 TOC." In 2018 XVII Russian Scientific and Practical Conference on Planning and Teaching Engineering Staff for the Industrial and Economic Complex of the Region (PTES). IEEE, 2018. http://dx.doi.org/10.1109/ptes.2018.8604155.
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"PTES 2018 Preface." In 2018 XVII Russian Scientific and Practical Conference on Planning and Teaching Engineering Staff for the Industrial and Economic Complex of the Region (PTES). IEEE, 2018. http://dx.doi.org/10.1109/ptes.2018.8604264.
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Kannan, Surya, and Serhiy Souchelnytski. "Post-Translational Modifications of Albumin in Cancer – A Rich Source for Diagnostic and Monitoring of Treatment." In Qatar University Annual Research Forum & Exhibition. Qatar University Press, 2020. http://dx.doi.org/10.29117/quarfe.2020.0171.
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Albumin is in contact with all cells in a body. This major protein in a plasma accesses all tissues and organs and has a number of different roles. Albumin was found to have more than 50 posttranslational modifications (PTMs). Some of the albumin PTMs showed correlation with tumorigenesis. Examples of PTMs of albumin are reported at www.phosphosite.org. Modifications like glycation of patients with breast cancer is seen higher as compared to healthy control. We hypothesize that several novel post-translational modification in albumin could be related to cancer and can be used as biomarkers. We performed mass spectrometry and 2D gel electrophoresis analysis of serum albumin for 32 most common PTMs. We identified most of these PTMs in albumin. We observed that human cancer cells affected PTMs profile of albumin. Examples of affected PTMs are phosphorylation, palmitolylation, geranyl- geranylation etc. We observed also differences in PTMs profiles of albumin from serum of a healthy person and cancer patient. O - GlcNAcylation, farnesylation, glutathionylation, S- nitrosylation etc PTMs were found to differ. Our data show that PTMs of albumin can be easily detected. Our trial with 32 PTMs can be expanded to detect up to a hundred known PTMs. These PTMs may correlate with cancer development, and may be used as markers in cancer diagnostic and prognostic.
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"PTES 2018 Title Page." In 2018 XVII Russian Scientific and Practical Conference on Planning and Teaching Engineering Staff for the Industrial and Economic Complex of the Region (PTES). IEEE, 2018. http://dx.doi.org/10.1109/ptes.2018.8604176.
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"PTES 2018 Author Index." In 2018 XVII Russian Scientific and Practical Conference on Planning and Teaching Engineering Staff for the Industrial and Economic Complex of the Region (PTES). IEEE, 2018. http://dx.doi.org/10.1109/ptes.2018.8604222.
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Thomsen, Lars, Benjamin Watts, Daniel Cotton, and Paul Dastoor. "PTMS alignment on Aluminium Oxide." In 2006 International Conference on Nanoscience and Nanotechnology. IEEE, 2006. http://dx.doi.org/10.1109/iconn.2006.340641.
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Kelly, Bethany, Kenny Nguyen, Zach Miles, Salvador Mayoral, Susan Piacenza, Cheng Zhang, and Joseph Piacenza. "Exploring Design Trades to Extend Useful Life of Platform Terminal Transmitters on Sea Turtles." In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-97473.
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Abstract Satellite-linked platform terminal transmitters (PTTs) are important tools for conducting research of sea turtles in their marine habitats. Appropriate conservation actions can be identified using PTTs, mounted to the top of sea turtles’ shells, to collect information about migratory routes and habitat usage. However, there is concern that PTTs introduce hydrodynamic drag that may bias natural sea turtle behavior, making the migratory and habitat data inaccurate representations of the “untagged” population. PTTs also have limited attachment durations, hypothesized to be caused by hydrodynamic loading and shell expansion during growth. The aim of this research is to investigate the hydrodynamic drag induced by PTTs on juvenile hard-shelled sea turtles, with the broader goal of increasing deployment duration and minimizing behavioral effects. A computational fluid dynamics (CFD) model was created to simulate the hydrodynamics of juvenile sea turtles. The drag and lift coefficients for five PTTs, virtually attached to the sea turtle model, were calculated using numerical methods. A comparison table of PTT performance is presented. The results will be used to explore PTT form factor design trades-offs that reduce hydrodynamic loading, while still meeting operational requirements. This research could enable biologists to collect data that more accurately represents the untagged sea turtle population.
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Frate, Guido Francesco, Luigia Paternostro, Lorenzo Ferrari, and Umberto Desideri. "Off-Design of a Pumped Thermal Energy Storage Based on Closed Brayton Cycles." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-60185.
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Abstract The growth of renewable energy source requires reliable, durable and cheap storage technologies. In this field, the Pumped Thermal Energy Storage (PTES), is drawing some interest as it appears not to be affected by geographical limitations and use very cheap materials. PTES is less efficient than pumped hydro and batteries, but it could achieve satisfactory efficiencies, show better economic performance and be characterized by negligible environmental impacts. A PTES stores the electric energy as thermal exergy in solid packed beds, by operating two closed Brayton cycles, one for charging and the other one for discharging. Although PTES thermodynamical behavior is well understood, the interaction between the components is rarely investigated. This study investigates the impact of packed-bed behavior on turbomachines operating conditions. In this way, PTES off-design and part-load performance are estimated. A control strategy especially suited for closed Brayton cycles, i.e. the inventory control, is used to control the system. As it resulted, PTES is characterized by an excellent part-load performance, which might be a significant advantage over the competing technologies. However, the off-design operation induced by the packed-bed thermal behavior might significantly reduce the system performance and, in particular, that of the discharge phase.
Reports on the topic "PTXs"
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Nagahi, Morteza, Raed Jaradat, Safae El Amrani, Michael Hamilton, and Simon Goerger. Holistic and reductionist thinker : a comparison study based on individuals’ skillset and personality types. Engineer Research and Development Center (U.S.), May 2021. http://dx.doi.org/10.21079/11681/40746.
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As organizations operate in turbulent and complex environments, it has become a necessity to assess the systems thinking (ST) skills, personality types (PTs), and demographics of practitioners. In this study, we investigated the relationship between practitioners’ ST profile, their PTs profiles and demographic characteristics in the domain of complex system problems. The objective of this study is to address the current gap in the literature – lack of studies dedicated to predicting practitioners’ ST profile based on their PTs and demographics characteristics. A total of 258 practitioners with different demographics and PTs provided the data. The results show that (1) practitioners can be classified based on their ST skills scores into two clusters: holistic and reductionist (that is, ST profile), (2) each cluster has different PTs profiles and demographic characteristics, and (3) practitioner’s ST profile can be predicted, with good accuracy, based on their PTs profile and demographic characteristics.
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Hansen, Christopher P., Mark A. Rumble, R. Scott Gamo, and Joshua J. Millspaugh. Auxiliary VHF transmitter to aid recovery of solar Argos/GPS PTTs. Ft. Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 2014. http://dx.doi.org/10.2737/rmrs-rn-72.
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Prusa, Thomas, and Robert Teh. Protection Reduction and Diversion: PTAs and the Incidence of Antidumping Disputes. Cambridge, MA: National Bureau of Economic Research, August 2010. http://dx.doi.org/10.3386/w16276.
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Podlevsky, Joshua. Cas9 Protein Post-translational Modifications (PTMs): A Potential Biomarker of Gene-editing. Office of Scientific and Technical Information (OSTI), October 2019. http://dx.doi.org/10.2172/1571552.
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Nagahi, Morteza, Raed Jaradat, Simon Goerger, Michael Hamilton, Randy Buchanan, Sawsan Abutabenjeh, and Junfeng Ma. The impact of practitioners’ personality traits on their level of systems-thinking skills preferences. Engineer Research and Development Center (U.S.), October 2022. http://dx.doi.org/10.21079/11681/45791.
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In this study, we used a structural equation modeling method to investigate the relationship between systems engineers and engineering managers’ Systems-Thinking (ST) skills preferences and their Personality Traits (PTs) in the domain of complex system problems. As organizations operate in more and more turbulent and complex environments, it has become increasingly important to assess the ST skills preferences and PTs of engineers. The current literature lacks studies related to the impact of systems engineers and engineering managers’ PTs on their ST skills preferences, and this study aims to address this gap. A total of 99 engineering managers and 104 systems engineers provided the data to test four hypotheses posed in this study. The results show that the PTs of systems engineers and engineering managers have a positive impact on their level of ST skills preferences and that the education level, the current occupation type, and the managerial experience of the systems engineers and engineering managers moderate the main relationship in the study.
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Yu, Yiqi, April Novak, Dillon Shaver, and Elia Merzari. Multi physics simulation on Reactor Pressure Vessel (RPV) subjected to Pressurized Thermal Shock (PTS). Office of Scientific and Technical Information (OSTI), May 2022. http://dx.doi.org/10.2172/1876833.
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Avis, William. China’s Preferential Trading Schemes for Developing Countries. Institute of Development Studies, August 2022. http://dx.doi.org/10.19088/k4d.2022.134.
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This literature review collates available evidence on China’s preferential trading schemes for developing countries. It draws on a diverse range of sources from multiple academic disciplines and grey literature. The review focuses explicitly on that literature that discusses preferential trade agreements as a specific form of free trade agreements. The review acknowledges that impacts are multidimensional and multifaceted and will be reflected differently across sectors and countries making conclusions hard to reach. One of the most important elements of many countries trade policy since the turn of the century has been the rapid growth of various forms of Free Trade Agreements (FTAs). There are different definitions of PTAs, some include regional trade agreements as a form of PTA i.e. where a country gives preferential trade to your regional partners - this is not always true and WTO does not define RTAs as PTA. A preferential trade area established via a preferential trade agreement is a trading bloc that gives preferential access to certain products from participating countries. This is accomplished by reducing trade tariffs and is considered a first stage of economic integration.
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Simonen, Fredric A., Stephen R. Gosselin, and Steven R. Doctor. Technical Letter Report Development of Flaw Size Distribution Tables Including Effects of Flaw Depth Sizing Errors for Draft 10CFR 50.61a (Alternate PTS Rule) JCN-N6398, Task 4. Office of Scientific and Technical Information (OSTI), April 2013. http://dx.doi.org/10.2172/1077999.
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Nagahi, Morteza, Niamat Ullah Ibne Hossain, Safae El Amrani, Raed Jaradat, Laya Khademibami, Simon Goerger, and Randy Buchanan. Investigating the influence of demographics and personality types on practitioners' level of systems thinking skills. Engineer Research and Development Center (U.S.), March 2022. http://dx.doi.org/10.21079/11681/43622.
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Although the application of systems thinking (ST) has become essential for practitioners when dealing with turbulent and complex environments, there are limited studies available in the current literature that investigate how the ST skills of practitioners vary with regard to demographic factors and personality types (PTs). To address this gap, this article uses a structural equation modeling approach to explore the relationship be-tween practitioners’ ST skills, PT, and a set of demographic factors. The demographic factors included in the study are education level, the field of the highest degree, organizational ownership structure, job experience, and current occupation type. A total of 99 engineering managers, 104 systems engineers (SEs), and 55 practitioners with other occupations participated in this article. Results showed that the education level, the field of the highest degree, PT, organizational ownership structure, and current job experience of practitioners influenced their level of ST skills. Additionally, the current occupation type of practitioners partially affects their level of ST skills. An in-depth analysis was also conducted using multiple group analysis to show how seven ST skills of the practitioners vary across their level of education. Taken together, the findings of the study suggest that PT and a set of demographic factors influence the overall ST skill of the practitioners.
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Datta, Sandip, and Geeta Kingdon. Class Size and Learning: Has India Spent Too Much on Reducing Class Size? Research on Improving Systems of Education (RISE), January 2021. http://dx.doi.org/10.35489/bsg-rise-wp_2021/059.
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This paper examines the efficacy of class-size reductions as a strategy to improve pupils’ learning outcomes in India. It uses a credible identification strategy to address the endogeneity of class-size, by relating the difference in a student’s achievement score across subjects to the difference in his/her class size across subjects. Pupil fixed effects estimation shows a relationship between class size and student achievement which is roughly flat or non-decreasing for a large range of class sizes from 27 to 51, with a negative effect on learning outcomes occurring only after class size increases beyond 51 pupils. The class-size effect varies by gender and by subject-stream. The fact that up to a class-size of roughly 40 in science subjects and roughly 50 in non-science subjects, there is no reduction in pupil learning as class size increases, implies that there is no learning gain from reducing class size below 40 in science and below 50 in non-science. This has important policy implications for pupil teacher ratios (PTRs) and thus for teacher appointments in India, based on considerations of cost-effectiveness. When generalised, our findings suggest that India experienced a value-subtraction from spending on reducing class-sizes, and that the US$3.6 billion it spent in 2017-18 on the salaries of 0.4 million new teachers appointed between 2010 and 2017 was wasteful spending rather than an investment in improving learning. We show that India could save US$ 19.4 billion (Rupees 1,45,000 crore in Indian currency) per annum by increasing PTR from its current 22.8 to 40, without any reduction in pupil learning.