Academic literature on the topic 'WW 2'
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 'WW 2.'
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 "WW 2"
1
Schilmann, Astrid, Andrés Sánchez-Pájaro, Marbella T. Ovilla-Muñoz, Juan Téllez-Sosa, Sugey Bravo-Romero, Sara Yuvisela Bahena-Reyes, Margarita Lobato, et al. "SARS-CoV-2 Wastewater Surveillance in Ten Cities from Mexico." Water 15, no. 4 (February 17, 2023): 799. http://dx.doi.org/10.3390/w15040799.
Full textAbstract:
We aimed to estimate the lead time and infection prevalence from SARS-CoV-2 wastewater (WW) monitoring compared with clinical surveillance data in Mexico to generate evidence about the feasibility of a large-scale WW surveillance system. We selected 10 WW treatment plants (WWTP) and 5 COVID-19 hospitals in major urban conglomerates in Mexico and collected biweekly 24-h flow-adjusted composite samples during October–November 2020. We concentrated WW samples by polyethylene glycol precipitation and employed quantitative PCR (RT-qPCR) assays, targeting the nucleoprotein (N1 and N2) genes. We detected and quantified SARS-CoV-2 RNA in 88% and 58% of the raw WW samples from WWTPs and COVID-19 hospitals, respectively. The WW RNA daily loads lead the active cases by more than one month in large and medium WWTP sites. WW estimated that cases were 2 to 20-fold higher than registered active cases. Developing a continuous monitoring surveillance system for SARS-CoV-2 community transmission through WW is feasible, informative, and recognizes three main challenges: (1) WW system data (catchment area, population served), (2) capacity to maintain the cold-chain and process samples, and (3) supplies and personnel to ensure standardized procedures.
2
Robotto, Angelo, Carlotta Olivero, Elisa Pozzi, Claudia Strumia, Camilla Crasà, Cristina Fedele, Maddalena Derosa, et al. "Efficient wastewater sample filtration improves the detection of SARS-CoV-2 variants: An extensive analysis based on sequencing parameters." PLOS ONE 19, no. 5 (May 24, 2024): e0304158. http://dx.doi.org/10.1371/journal.pone.0304158.
Full textAbstract:
During the SARS-CoV-2 pandemic, many countries established wastewater (WW) surveillance to objectively monitor the level of infection within the population. As new variants continue to emerge, it has become clear that WW surveillance is an essential tool for the early detection of variants. The EU Commission published a recommendation suggesting an approach to establish surveillance of SARS-CoV-2 and its variants in WW, besides specifying the methodology for WW concentration and RNA extraction. Therefore, different groups have approached the issue with different strategies, mainly focusing on WW concentration methods, but only a few groups highlighted the importance of prefiltering WW samples and/or purification of RNA samples. Aiming to obtain high-quality sequencing data allowing variants detection, we compared four experimental conditions generated from the treatment of: i) WW samples by WW filtration and ii) the extracted RNA by DNase treatment, purification and concentration of the extracted RNA. To evaluate the best condition, the results were assessed by focusing on several sequencing parameters, as the outcome of SARS-CoV-2 sequencing from WW is crucial for variant detection. Overall, the best sequencing result was obtained by filtering the WW sample. Moreover, the present study provides an overview of some sequencing parameters to consider when optimizing a method for monitoring SARS-CoV-2 variants from WW samples, which can also be applied to any sample preparation methodology.
3
Ashton, Elizabeth, Benjamin Smeeton, and Stuart Weatherby. "ONE YEAR RETROSPECTIVE AUDIT OF CNS MALIGNANCY 2 WW REFERRALS." Journal of Neurology, Neurosurgery & Psychiatry 86, no. 11 (October 14, 2015): e4.126-e4. http://dx.doi.org/10.1136/jnnp-2015-312379.37.
Full textAbstract:
BackgroundSince its introduction in 2000, concerns have been raised about the two week wait (2 WW) referral system for suspected malignancy. Studies have demonstrated poor compliance to guidelines, low detection rates and questioned the time effectiveness of the referral process.MethodAll patients referred under the 2 WW system for suspected CNS malignancy to Derriford Hospital, Plymouth Hospitals NHS trust, over a one-year period were retrospectively audited. Data was gained from clinic letters and radiological imaging. The aims were to determine the number of referrals, their appropriateness and subsequent time taken to outpatient appointment, imaging and final diagnosis.Results103 referrals were made between September 2013 and September 2014 with just 48.5% fulfilling NICE referral guidelines for suspected CNS malignancy. Just three tumours were diagnosed with guidelines identifying all of these. Only 28% of 2 WW referrals received diagnostic imaging and an outpatient appointment within two weeks.ConclusionsUnnecessary referrals are placing strain on the 2 WW system. We suggest that a potential solution is for general practitioners to refer patients for imaging at the same time as they make their neurological 2 WW referral in order to cut down waiting times.
4
LOTT, J. Shaun, Sarah J. CODDINGTON-LAWSON, Paul H. TEESDALE-SPITTLE, and Fiona J. MCDONALD. "A single WW domain is the predominant mediator of the interaction between the human ubiquitin-protein ligase Nedd4 and the human epithelial sodium channel." Biochemical Journal 361, no. 3 (January 25, 2002): 481–88. http://dx.doi.org/10.1042/bj3610481.
Full textAbstract:
The activity of the epithelial Na+ channel (ENaC) is required for the maintenance of salt and water balance in the body. Channel activity is regulated by the ubiquitin-protein ligase Nedd4 ['neuronal precursor cell-expressed developmentally down-regulated (gene 4)'] that interacts with the channel via its WW domains. Mutations in channel subunits that disrupt this interaction cause Liddle's syndrome, a severe inherited form of hypertension. In previous studies we showed that WW domains 2, 3 and 4 of human Nedd4 bound to the human ENaC (hENaC) subunits, whereas WW domain 1 did not. Here we extend this observation to determine the binding affinities of the human Nedd4 WW domains for hENaC C-terminal peptides. We show that WW domains 2, 3 and 4 bind with differing affinities to Na+ channel subunit peptides. WW domain 3 has the highest affinity and we predict that WW domain 3 contributes most of the binding because a construct containing the three WW domains bound no better than WW domain 3 alone. Further, a single amino acid change (Arg165 → Thr) in WW domain 1 enables binding to the α subunit of the channel to occur, with an affinity comparable with that of WW domain 4. Differential binding propensities between the various WW domains and Na+ channel subunit peptides are explained on the basis of quantitative structural modelling of the complexes and their isolated components.
5
Schillinger, William F., and David W. Archer. "Winter Triticale: A Long-Term Cropping Systems Experiment in a Dry Mediterranean Climate." Agronomy 10, no. 11 (November 13, 2020): 1777. http://dx.doi.org/10.3390/agronomy10111777.
Full textAbstract:
Triticale (X Triticosecale Wittmack) is a cereal feed grain grown annually worldwide on 4.2 million ha. Washington is the leading state for rainfed (i.e., non-irrigated) triticale production in the USA. A 9-year dryland cropping systems project was conducted from 2011 to 2019 near Ritzville, WA to compare winter triticale (WT) with winter wheat (Triticum aestivum L.) (WW) grown in (i) a 3-year rotation of WT-spring wheat (SW) -no-till summer fallow (NTF) (ii) a 3-year rotation of WW-SW-undercutter tillage summer fallow (UTF) and (iii) a 2-year WW-UTF rotation, We measured grain yield, grain yield components, straw production, soil water dynamics, and effect on the subsequent SW wheat crop (in the two 3-year rotations). Enterprise budgets were constructed to evaluate the production costs and profitability. Grain yields averaged over the years were 5816, 5087, and 4689 kg/ha for WT, 3-year WW, and 2-year WW, respectively (p < 0.001). Winter triticale used slightly less water than WW (p = 0.019). Contrary to numerous reports in the literature, WT never produced more straw dry biomass than WW. Winter wheat produced many more stems than WT (p < 0.001), but this was compensated by individual stem weight of WT being 60% heavier than that of WW (p < 0.001). Spring wheat yield averaged 2451 vs. 2322 kg/ha after WT and WW, respectively (p = 0.022). The market price for triticale grain was always lower than that for wheat. Winter triticale produced an average of 14 and 24% more grain than 3-year and 2-year WW, respectively, provided foliar fungal disease control, risk reduction, and other rotation benefits, but was not economically competitive with WW. A 15–21% increase in WT price or grain yield would be necessary for the WT rotation to be as profitable as the 3-year and 2-year WW rotations, respectively.
6
Kakehi, Y., T. Kamoto, O. Ogawa, K. Tobisu, Y. Saito, H. Fukuda, and T. Kakizoe. "Prospective evaluation of a “Watchful Waiting” program using initial pathology criteria and PSA-doubling time monitoring for patients with stage T1c prostate cancer." Journal of Clinical Oncology 24, no. 18_suppl (June 20, 2006): 14651. http://dx.doi.org/10.1200/jco.2006.24.18_suppl.14651.
Full textAbstract:
14651 Background: “Watchful waiting (WW)” is becoming a common treatment option for patients (pts) with screening detected prostate cancer. There is, however, no consensus about which pts are suitable for WW and how pts are monitored. Methods: Eligibility criteria: 1) stage T1c prostate cancer pts, 2) age 50–80, 3) serum PSA: 20 ng/ml or less, 4) 1 or 2 positive cores per 6 to 12 systematic core biopsies, 5) Gleason score of 6 or less, 6) 50% or less maximum % cancer occupation in a positive core. The criteria of 4), 5), 6) were confirmed by a central pathologist before pts registration. Registered patients chose either WW or immediate aggressive treatment. In patients who chose WW, serum PSA was monitored every 2 months for 6 months and PSA-doubling time (PSADT) was calculated centrally. Those who showed PSADT 2y and re-biopsy at 13 months fit the initial pathology criteria again. Primary endpoint was “% PSADT > 2 y”, which was defined as proportion of patients who showed PSADT at 6 months > 2 y out of all patients who chose WW. Point estimate of “% PSADT > 2 y” was expected to be higher than 80%. The planned sample size was 100 pts who chose WW, which gives the width of 95% confidence intervals for % PSADT > 2 y within 10%. Results: 134 pts were enrolled from 01/2002 to 12/2003 and 118 pts chose WW while 13 pts chose aggressive treatment (surgery, radiotherapy, hormonal therapy). The initial 6 months’ PSADT could be assessed in 106 patients (measurement point error in 6, early dropout in 6). Of 106 patients, 22 showed PSADT < 2 y (“rapid riser”) while 84 showed PSADT > 2 y. “% PSADT > 2 y” was 71.2% (84/118, 95% CI: 62.1–79.2%). 84 pts have continued WW with median follow-up of 27 months. Neither metastasis nor cancer-death was observed until 06/2005. As to health-related QOL, any domain of SF-36 was not impaired in patients who continued WW at least for 1 year. Conclusion: Our initial selection criteria for WW may include at least 20% of “rapid riser”, hence need further modification. Additionally, it should be confirmed by further follow-up of 84 pts whether eliminating “rapid riser” from WW by initial 6 months’ PSADT is appropriate. No significant financial relationships to disclose.
7
Fleet, M. R., S. F. Lincoln, and A. M. Hounslow. "Electron spin resonance of wool from Merino sheep heterozygous or homozygous for white fleece." Animal Science 47, no. 1 (August 1988): 97–103. http://dx.doi.org/10.1017/s0003356100037090.
Full textAbstract:
AbstractWool samples were collected from two groups of Merino sheep, both of which contained animals that were either heterozygous (Ww) or homozygous (WW) for white fleece. Group 1 were sampled in summer and group 2 in winter. These samples were scoured and measured for electron spin resonance initially (ESR1), following irradiation by ultraviolet light (ESR2) and then after wetting and drying the sample (ESR3).There was no significant difference between WW and Ww sheep in each group for any of the ESR measurements (P > 0·05). However, for ESR1 there was a difference between management groups (group 1> group 2; P < 0·05). The ESR3 on ESR1 values were plotted separately for WW and Ww genotypes. The plotted ESR3 on ESR1 values in both groups showed no differentation into distinct genotype clusters. Nevertheless, for group 2 there was a slight similarity to the cross-like pattern of genotypes reported in an earlier description of this technique and the regression coefficients of ESR3 on ESR1 for WW sheep (b = −0·09 (s.e. 0·28)) differed significantly from those of Ww sheep (b = 1·31 (s.e. 0·52)) (P < 0·05).It appears that the previously published method for differentiating between sheep that are either heterozygous or homozygous for white fleece was ineffective in this case.
8
Jasiński OFM, Andrzej Sebastian. "Pokutna modlitwa psalmisty." Scriptura Sacra, no. 21 (July 17, 2021): 71–83. http://dx.doi.org/10.25167/scrs/4158.
Full textAbstract:
Ps 6 jest lamentem indywidualnym (struktura: ww. 2-4 lament; ww. 5-8 modlitwa o uzdrowienie; ww. 9-11 dziękczynienie). Lamenty w Biblii dotyczą bardzo różnorodnej tematyki. Ps 6 jest pierwszym z siedmiu psalmów pokutnych (Ps 6; 32; 38; 51; 102; 130; 143). Ww. 2-3 ukazują wszechobecną moc grzechu. Grzech ma wpływ na całą egzystencję, o czym świadczy użycie słów „kości” (fizyczne) i „dusza” (cała istota). W istocie psalmista próbuje błagać Boga, mówiąc: „Jeśli mnie nie wybawisz, będziesz miał o jednego czciciela mniej”. Psalmista kładzie wysoką wartość na chwałę Boga jako kartę przetargową.
9
Gomes, Marta, Maria Bartolomeu, Cátia Vieira, Ana T. P. C. Gomes, Maria Amparo F. Faustino, Maria Graça P. M. S. Neves, and Adelaide Almeida. "Photoinactivation of Phage Phi6 as a SARS-CoV-2 Model in Wastewater: Evidence of Efficacy and Safety." Microorganisms 10, no. 3 (March 19, 2022): 659. http://dx.doi.org/10.3390/microorganisms10030659.
Full textAbstract:
The last two years have been marked by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. This virus is found in the intestinal tract; it reaches wastewater systems and, consequently, the natural receiving water bodies. As such, inefficiently treated wastewater (WW) can be a means of contamination. The currently used methods for the disinfection of WW can lead to the formation of toxic compounds and can be expensive or inefficient. As such, new and alternative approaches must be considered, namely, photodynamic inactivation (PDI). In this work, the bacteriophage φ6 (or, simply, phage φ6), which has been used as a suitable model for enveloped RNA viruses, such as coronaviruses (CoVs), was used as a model of SARS-CoV-2. Firstly, to understand the virus’s survival in the environment, phage φ6 was subjected to different laboratory-controlled environmental conditions (temperature, pH, salinity, and solar and UV-B irradiation), and its persistence over time was assessed. Second, to assess the efficiency of PDI towards the virus, assays were performed in both phosphate-buffered saline (PBS), a commonly used aqueous matrix, and a secondarily treated WW (a real WW matrix). Third, as WW is generally discharged into the marine environment after treatment, the safety of PDI-treated WW was assessed through the determination of the viability of native marine water microorganisms after their contact with the PDI-treated effluent. Overall, the results showed that, when used as a surrogate for SARS-CoV-2, phage φ6 remains viable in different environmental conditions for a considerable period. Moreover, PDI proved to be an efficient approach in the inactivation of the viruses, and the PDI-treated effluent showed no toxicity to native aquatic microorganisms under realistic dilution conditions, thus endorsing PDI as an efficient and safe tertiary WW disinfection method. Although all studies were performed with phage φ6, which is considered a suitable model of SARS-CoV-2, further studies using SARS-CoV-2 are necessary; nevertheless, the findings show the potential of PDI for controlling SARS-CoV-2 in WW.
10
Kamynina, Elena, Caroline Tauxe, and Olivier Staub. "Distinct characteristics of two human Nedd4 proteins with respect to epithelial Na+ channel regulation." American Journal of Physiology-Renal Physiology 281, no. 3 (September 1, 2001): F469—F477. http://dx.doi.org/10.1152/ajprenal.2001.281.3.f469.
Full textAbstract:
The epithelial Na+ channel (ENaC) is regulated via PY motif-WW domain interaction by the mouse (m) ubiquitin-protein ligase mNedd4-2 but not by its close relative mNedd4-1. Whereas mNedd4-1 is composed of one C2, three WW, and one HECT domain, mNedd4-2 comprises four WW domains and one HECT domain. Both proteins have human (h) homologs, hNedd4-1 and hNedd4-2; however, both of them include four WW domains. Therefore, we characterized hNedd4-1 and hNedd4-2 in Xenopus laevisoocytes with respect to ENaC binding and interaction. We found that hNedd4-2 binds to and abrogates ENaC activity, whereas hNedd4-1 does not coimmunoprecipitate with ENaC and has only modest effects on ENaC activity. Structure-function studies revealed that the C2 domain of hNedd4-1 prevents this protein from downregulating ENaC and that WW domains 3 and 4, involved in interaction with ENaC, do not by themselves provide specificity for ENaC recognition. Taken together, our data demonstrate that hNedd4-2 inhibits ENaC, implying that this protein is a modulator of salt homeostasis, whereas hNedd4-1 is not primarily involved in ENaC regulation.
Dissertations / Theses on the topic "WW 2"
1
Tenner, Katja. "Funktionelle Charakterisierung der humanen Tryptophanhydroxylase 2." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2007. http://dx.doi.org/10.18452/15669.
Full textAbstract:
Die Tryptophanhydroxylase (TPH) katalysiert den geschwindigkeitsbestimmenden Schritt der Synthese des wichtigen Neurotransmitters Serotonin. Kürzlich wurde ein zweites TPH-Isozym, die TPH2, entdeckt. Es stellte sich heraus, dass dieses Isozym für die Serotoninsynthese im Zentralnervensystem verantwortlich ist, wohingegen die TPH1 lediglich der Ausgangspunkt der Serotoninsynthese in den peripheren Geweben ist. Da Störungen im Serotoninstoffwechsel mit einer Vielzahl von psychiatrischen Erkrankungen in Verbindung gebracht werden, rückt nun die als neuronales Enzym identifizierte TPH2 in den Fokus der Forschung. In dieser Arbeit konnte gezeigt werden, dass TPH1 und 2 sich nicht nur in ihren Expressionsorten sondern auch in ihren grundlegenden biochemischen Eigenschaften voneinander unterscheiden. Die TPH1 stellte sich als aktiveres der beiden Enzyme heraus. Der N- und C-Terminus der TPH2 konnten als auf die Aktivität des Enzyms inhibierend bzw. aktivierend wirkende Strukturen identifiziert werden und stellen damit interessante Angriffspunkte für die pharmakologische Beeinflussung dar, wobei der N-Terminus als TPH2-spezifische Struktur eine gezielte Beeinflussung des serotonergen Systems im Zentralnervensystem ohne Auswirkungen auf das periphere System ermöglichen würde. In weiteren Projekten konnte die Existenz von mindestens zwei, die Enzymaktivität nicht beeinflussenden Proteinkinase A-Phosphorylierungsstellen in der TPH2 nachgewiesen werden, es konnte ein auf einem fluorometrischen Prinzip basierender High-Throughput-Assay zur Bestimmung der TPH-Aktivität entwickelt werden, Tubulin beta2A wurde als Interaktionpartner der TPH2 identifiziert, die Auswirkungen eines in vitro aktivitätssenkenden Tph2-SNPs auf die Serotoninlevel und das Verhalten verschiedener Mausstämme konnte durch die Generierung und Untersuchung von congenen Mäusen als unbedeutend eingestuft werden und die Expression von TPH1-mRNA wurde als Marker für endometriale Karzinome identifiziert.Tryptophan hydroxylase (TPH) catalyzes the rate limiting step of the synthesis of the important neurotransmitter serotonin. Recently a new TPH isoenzyme, TPH2, was discovered. It turned out that this isoenzyme is responsible for the serotonin synthesis within the central nervous system, whereas the TPH1 is merely the starting point of serotonin synthesis in peripheral tissues. Since dysfunction in the metabolism of serotonin is related to a large number of psychiatric diseases, the neuronal TPH2 moved into the centre of interest. As a basis for the pharmacological manipulation of the central nervous serotonergic system, without influencing the periphery, the identification of differences between the two isoenzymes is essential. In this thesis it was shown that TPH1 and 2 not only differ in their expression sites but also in their basic biochemical characteristics. TPH1 turned out to be the more active enzyme. Furthermore it was shown that the N- and C-termini of TPH2 have an inhibitory respectively activating influence on the enzymatic activity. Therefore they became interesting targets for pharmacological interference, whereas the N-terminus as a TPH2 specific structure would facilitate the manipulation of the central nervous serotonergic system without exerting influence on the peripheral system. In further projects the existence of at least two protein kinase A phosphorylation sites could be verified, whereas the phosphorylation doesn’t seem to have any influence on the enzymatic activity, a high throughput assay for determination of TPH activity, based on a fluorometric principle, was developed, Tubulin beta2A was identified as a TPH2 interaction partner, the effect of a SNP in the Tph2 gene that decreases the TPH2 activity in vitro on the serotonin level and the behaviour of different mouse strains could be rated as insignificant by the generation of congenic mice und the expression of TPH1 mRNA was identified as a marker for endometrial cancer.
2
Labonne, B. "Origine et manifestation de la brisure de supersymétrie : Phénoménologie de l'annihilation de neutralinos en Zh et WW. Représentation (0,1/2) et dualité." Phd thesis, Université de la Méditerranée - Aix-Marseille II, 2007. http://tel.archives-ouvertes.fr/tel-00194510.
Full textAbstract:
La supersymétrie est une extension possible du modèle standard. Il faut en maîtriser autant les aspects formels que la phénoménologie caractéristique pour espérer découvrir si c'est une symétrie choisie par la nature. La supersymétrie offre un candidat privilégié pour la matière noire : le neutralino le plus léger , un des enjeux actuels est de comprendre au mieux les spectres d'annihilation de neutralinos produisant des particules détectables. Ainsi, le canal Zh est important de par la nature dure de son spectre. Cependant, la section efficace d'annihilation de neutralinos dans ce canal est supprimée quand la supersymétrie est brisée. L'annulation de ce canal est alors à chercher dans des phénomènes connus pour le MS : indépendance de jauge et unitarité UV de la théorie. En outre, la suppression est liée au caractère Majorana des neutralinos , mais aussi à la limite d'annihilation au repos, qui confère une polarisation au boson Z. Le même phénomène de polarisation est mis en évidence pour l'annihilation en WW. Néanmoins, la polarisation des W ne supprime pas le canal mais modifie la forme des spectres de ses produits de désintégration qui pourraient être détectés.D'un point de vue plus formel, les différentes représentations sur le super-espace du multiplet (0,1/2) sont passées en revue. Nous nous concentrons sur deux représentations spécifiques, le multiplet de 3-forme et le multiplet X. Le premier nous permet de réaliser un mécanisme de brisure de supersymétrie de type O'Raifeartaigh, sans singlet dans le superpotentiel. Le second multiplet contient les propriétés d'une brisure de supersymétrie. Nous mettons en évidence une relation de dualité entre ces deux représentations.
3
Labonne, Benjamin. "Origine et manifestation de la brisure de supersymétrie : Phénoménologie de l'annihilation de neutralinos en Zh et WW : Représentation (0,1/2) et dualité." Aix-Marseille 2, 2007. http://www.theses.fr/2007AIX22008.
Full text
4
Mosienko, Valentina. "Behavioral, neuronal, and development consequences of genetically decreased tryptophan hydroxylase 2 activity." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2014. http://dx.doi.org/10.18452/16885.
Full textAbstract:
Serotonin (5-Hydroxytryptamin, 5-HT) ist ein wichtiger Neurotransmitter im Zentralnervensystem (ZNS). Seine Biosynthese erfolgt unter Beteiligung des Enzyms Tryptophanhydroxylase 2 (TPH2). Polymorphismen im TPH2 Gen beim Menschen sind Risikofaktoren bei der Entstehung von Depressionen und Angstverhalten. Die gängigsten Antidepressiva und Anxiolytika wirken auf das Serotonin System. Unklar ist, ob das komplette oder teilweise Fehlen von Serotonin im Gehirn zu Entwicklungsstörungen und neurochemischen oder psychologischen Veränderungen führt. In dieser Arbeit werden Mauslinien mit unterschiedlichen TPH2 Aktivitäten im ZNS verglichen und der Einfluss verringerter 5-HT Konzentrationen auf Entwicklung und Verhalten der Tiere untersucht. Zentrales Serotonin ist nur für die postnatale Entwicklung notwendig. Das verzögerte Wachstum von Tph2-/- Tieren ist nicht auf eine Störung der Hypothalamus-Hypophysen-Nebennieren-Achse oder auf metabolische Veränderungen zurückzuführen, sondern kann aus verringerter Vokalisation im Ultraschallbereich resultieren. Tph2-/- Mäuse wurden mit generierten Mausmodellen mit niedriger TPH2 Aktivität vergleichen. Die Ergebnisse zeigen, dass 20% weniger zentrales Serotonin nicht ausreichen, um Depression oder Angst-Verhalten herbeizuführen. Möglicherweise greifen kompensatorische Mechanismen wie ein verringerter Serotoninmetabolismus oder eine gesteigerte 5-HT1A-Rezeptorsensitivität. Der komplette Verlust von Serotonin im Gehirn führt zu einem starken depressiven und weniger ängstlich Verhalten, mit erhöhter Aggression - ohne Veränderung in Aktivität, Geruchsinn, Gedächnis und adulter Neurogenese. Fluoxetine Behandlung von Tph2-defizienten Mäusen zeigte einen Serotonin-unabhängigen Effekt dieses Antodepressivums auf Angst-Verhalten und Depression. Fluoxeine reduzieren den Serotoningehalt im Gehirn von Mäusen mit geringen TPH2-Aktivität, was zeigt, dass TPH-Aktivität die Effizienz von Serotonin beeinflussenAntidepressiva bestimmen,Serotonin (5-HT) is a major neurotransmitter in the brain biosynthesis of which is initiated by tryptophan hydroxylase 2 (TPH2). Polymorphisms in the TPH2 gene are suggested as risk factors associated with depression and anxiety in humans. Furthermore, the most frequently prescribed antidepressants and anxiolytics target the serotonergic system. However, the question whether a complete ablation or partial reduction in brain serotonin leads to the developmental, neurochemical, or psychological abnormalities remains unresolved. In this study, I took advantage of mouse lines with various degree of decrease in TPH2 activity in order to dissect the impact of 5-HT loss on development, brain neurochemistry and behavior. Using Tph2-deficient mice I showed that central serotonin is essential for normal postnatal, but not prenatal development. Growth retardation of Tph2-/- mice was not a result of a disruption of the hypothalamo-pituitary-adrenal axis, metabolic abnormalities, or impaired thermoregulation, but could result from reduced ultrasonic vocalization. I tested Tph2-/- mice along with other newly generated mouse models with partial TPH2 reduction, and showed that 20% reduction in central serotonin is not enough to cause changes in anxiety- and depression-like behaviors most likely due to compensatory mechanisms including reduced serotonin metabolism and increased 5-HT1A receptor sensitivity. However, complete loss of central serotonin leads to a depression-like phenotype, reduced anxiety-like behavior, and exaggerated aggression, but no differences in activity, olfaction, memory, and adult neurogenesis. Fluoxetine treatment of Tph2-/- mice revealed serotonin-independent action of this antidepressant on anxiety- and depression-like behavior. Furthermore, fluoxetine drastically reduced the brain 5-HT content in mice with low TPH2 activity indicating that TPH2 activity may determine the efficiency of antidepressants targeting the serotonergic system.
5
Kaup, Daniel. "Wirkung der AT2-Überexpression auf Collagen I alpha 2-mRNA-Gehalt und Migration porciner kardialer Fibroblasten." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2003. http://dx.doi.org/10.18452/14848.
Full textAbstract:
In der vorliegenden Arbeit wurde der Einfluss der humanen AT2-Rezeptorexpression und -stimulation auf den Collagen I alpha 2-mRNA-Gehalt und die Migration von porcinen kardialen Fibroblasten untersucht, um die Frage zu klären, ob AT2-Rezeptoren in kultivierten kardialen Fibroblasten AT1-antagonistische antifibrotische und migrationshemmende Effekte auf den Collagen I alpha 2-mRNA-Gehalt bzw. die Migration ausüben. Um die Funktion der AT2-Rezeptoren in der Zellkultur untersuchen zu können, wurde die AT2-cDNA durch adenovirale Transduktion in die Fibroblasten übertragen und so der AT2-Rezeptor überexprimiert. Mittels RT-PCR wurden die relativen Änderungen im Collagen I alpha 2-mRNA-Gehalt in TGF-beta1- bzw. TGF-beta1 plus Ang II-stimulierten Fibroblasten im Vergleich zur unstimulierten Kontrolle bestimmt. Alle Werte wurden auf ein Referenzgen (beta-Actin) bezogen. Die AT2-Stimulation änderte den relativen Collagen I alpha 2-mRNA-Gehalt der Fibroblasten nicht signifikant gegenüber den Antisense-(Ad5TA2)-transduzierten Fibroblasten. In der modifizierten Boyden-Kammer wurde der AT2-vermittelte Effekt von Ang II, hPDGF-BB sowie der Kombination beider Stoffe auf die Migration untersucht. Die alleinige Stimulation von AT2-Rezeptoren mit Ang II verhinderte die Migration gegenüber nichttransduzierten Fibroblasten. In Kombination mit hPDGF-BB änderte Ang II die Migration in AT2-überexprimierenden Fibroblasten nicht gegenüber den Antisense-(Ad5TA2)-transduzierten Fibroblasten. Bei ausschließlicher Stimulation durch hPDGF-BB wurde aber in AT2-exprimierenden Fibroblasten eine signifikant geringere Migration als in Antisense-(Ad5TA2)-transduzierten Fibroblasten festgestellt. Die zugrunde liegende Hypothese, dass AT2-Expression und Stimulation den relativen Collagen I alpha 2-mRNA-Gehalt hemmt, konnte in den vorliegenden Experimenten nicht bestätigt werden. Dies ließ keine inhibitorische AT2-vermittelte Wirkung von Ang II im Bezug auf den TGF-beta1-induzierten Collagen I alpha 2-mRNA-Gehalt erkennen. Dagegen führte die Ang II-Stimulation überexprimierter AT2-Rezeptoren zu einer verringerten Migration und vermittelte so einen AT1-antagonistischen Effekt.In this work the influence of expression and stimulation of the human AT2 receptor on Collagen I alpha 2-mRNA-content and migration of porcine cardiac fibroblastst was tested to clarify the question if AT2 receptors promote AT1 antagonistic antifibrotic and antimigratory effects on collagen I alpha 2-mRNA content and migration. To examine the AT2 receptor function in the cell culture AT2 cDNA was transferred into fibroblasts by adenoviral transduction and the AT2 receptor was overexpressed. Through the use of RT-PCR the relative changes in collagen I alpha 2-mRNA content in TGF-beta1 stimulated and TGF-beta1 plus Ang II stimulated fibroblasts were assayed and compared to the unstimulated control. All values were referred to a reference gene (beta-actin). Stimulation of AT2 receptors did not change the relative collagen I alpha 2-mRNA content of the fibroblasts significantly compared to antisense-(Ad5TA2) transduced fibroblasts. In the modified Boyden-chamber the AT2 mediated effect of Ang II, hPDGF-BB and the combination of both on migration was assessed. The stimulation of AT2 receptors with Ang II inhibited migration compared to nontransduced fibroblasts. In combination with hPDGF-BB Ang II did not change the migration in AT2 overexpressing fibroblasts compared to antisense-(Ad5TA2)-transduced fibroblasts. In the case of exclusive stimulation of AT2-expressing fibroblasts with hPDGF-BB a significantly lower migration was found compared to antisense-(Ad5TA2)-transduced fibroblasts. The underlying therory that AT2 expression and stimulation inhibits the relative collagen I alpha 2-mRNA content could not be confirmed in this work. This did not reveal an inhibitory AT2 mediated effect of Ang II in respect to the TGF-beta1 induced collagen I alpha 2-mRNA content. In contrast to that Ang II stimulation of overexpressed AT2 receptors led to a decreased migration and mediated an AT1 antagonistic effect.
6
DiCesare, Silvana. "The guanine nucleotide exchanger Vav2 interacts with c-ErbB-2 and induces alveolar morphogenesis of mammary epithelial cells." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2002. http://dx.doi.org/10.18452/14693.
Full textAbstract:
Die Familie der ErbB-Rezeptor-Tyrosinkinasen besteht aus vier Mitgliedern, dem EGF-Rezeptor (ErbB-1), ErbB-2, ErbB-3 und ErbB-4. ErbB-Rezeptoren spielen eine wichtige Rolle bei der Entwicklung des Nervensystems, des Herzens und der Brustdrüsen. Ein Teil dieser Differenzierungsvorgänge läßt sich in vitro nachvollziehen: so ist zum Beispiel die Aktivierung des ErbB-2 Rezeptors ausreichend für alveoläre Morphogenese der Brustdrüsenepithelzellinie EpH4. Intrazelluläre Moleküle, die dieses ErbB2-Signal übertragen, sind allerdings noch unbekannt. Mit Hilfe eines neuen, modifizierten Hefe-2-Hybrid-Systems wurde in der vorliegenden Arbeit Vav2 als neuer Interaktionspartner von ErbB-2 identifiziert. Vav2 assoziiert mit aktiviertem ErbB-2 über eine SH2-Domäne. Die Interaktion ist direkt und ist von zwei Phosphotyrosinen in ErbB-2 abhängig. Vav2 kann den GDP/GTP-Austausch bei GTPasen der Rho-Familie vermitteln. Dadurch kann der Umbau des Zytoskeletts und Veränderungen der Transkription sowie Zelltransformation induziert werden. In einem dreidimensionalen Zellkultursystem kann aktiviertes Vav2 in EpH4 Zellen die Bildung von alveolären Zellaggregaten induzieren. In diesen Alveolen umgibt eine Schicht polarisierter milchproduzierender Zellen ein zentrales Lumen. Diese Vav2-vermittelte Morphogenese ist abhängig von der katalytischen GDP/GTP-Austausch Aktivität von Vav2. Katalytisch-inaktives Vav2 kann die morphogenetische Aktivität von ErbB-2 in EpH4-Zellen verhindern, ohne die mitogene Aktivität von ErbB-2 zu beeinflussen. Vav2 ist mit ErbB-2 coexprimiert und interagiert mit dem Rezeptor in Brustdrüsenzellen schwangerer Mäuse. Diese Untersuchungen deuten darauf hin, dass Vav2 eine wichtige Funktion bei der durch ErbB-2 induzierten alveolären Morphogenese der Brustdrüse spielt.The ErbB receptor tyrosine kinases constitute a subfamily of four structurally related members, the EGF receptor (ErbB-1), ErbB-2, ErbB-3 and ErbB-4. ErbB receptor tyrosine kinases are critical for embryonic development of central and peripheral neural structures and heart. In addition, ErbB receptors play an important role in the postnatal development of the mammary gland. Previous studies showed that activated ErbB-2 receptor induces alveolar morphogenesis of EpH4 mammary epithelial cells that are cultured on a three-dimensional matrix (termed Matrigel). However, the downstream signaling proteins that mediate this biological activity of ErbB-2 were unknown. In this work, Vav2 was identified as a direct interaction partner of tyrosine-phosphorylated ErbB receptors using the yeast two-hybrid system. Vav2 is a member of a family of guanine nucleotide exchange factors that induce cytoskeletal rearrangements, transcriptional alterations, and have oncogenic potential when activated. To test the ability of Vav2 to mediate morphogenic signals of ErbB-2, EpH4 cells overexpressing Vav2 protein were cultured on Matrigel. Indeed, Vav2 induces alveolar morphogenesis of EpH4 cells when activated either by oncogenic mutation or tyrosine phosphorylation by ErbB-2. The morphogenic activity of Vav2 requires the Dbl homology domain, which mediates GDP/GTP exchange. Dominant-negative Vav2 specifically blocks the morphogenic signals of ErbB-2 in EpH4 cells without interfering with ErbB2-induced mitogenesis. Importantly, Vav2 is co-expressed and interacts with ErbB-2 in the mammary glands of pregnant mice. Taken together, these results point to Vav2 as a candidate to mediate ErbB-2 signals for alveolar morphogenesis in vivo, which is a relevant step in the development of the mammary gland during pregnancy.
7
Corvaisier, Matthieu. "Implication des co-activateurs transcriptionnels YAP/TAZ dans la régulation entre la croissance et la dormance tumorale des cellules du cancer colorectal : mécanismes moléculaires et perspectives thérapeutiques." Thesis, Lille 2, 2016. http://www.theses.fr/2016LIL2S028/document.
Full textAbstract:
Le cancer colorectal est la première pathologie cancéreuse de la sphère digestive, tant en terme de fréquence que de mortalité par an. Chaque année, 41 000 nouveaux cas sont diagnostiqués et 17 000 décès sont dus à ce cancer en France. Deux paramètres cliniques expliquent la mortalité de ce cancer; d'une part le fait qu'un patient sur deux est diagnostiqué au stade métastatique ou va présenter des lésions métastatiques durant l'histoire de sa pathologie, d'autre part le fait que les patients après traitement vont fréquemment présenter une récidive de leur pathologie. L'utilisation de régimes de chimiothérapies avant et après résection métastatique améliore la survie sans récidive à court terme, mais à 2 ans post chirurgie l'avantage apporté est perdu. Ainsi, la compréhension des mécanismes d'échappement à la chimiothérapie et régissant la croissance tumorale est d'intérêt pour tenter de limiter la récidive tumorale. L'objectif de ce travail de thèse a consisté en l'analyse de sous-populations obtenues sous pression de chimiothérapie au 5-Fluorouracile (5FU) dérivées de la lignée cancéreuse colique HT29, ainsi que les mécanismes moléculaires associés. Notre clone le plus chimiorésistant isolé, le modèle cellulaire 5F31, quitte le compartiment prolifératif sous traitement à fortes doses de 5FU, ceci étant associé à une perturbation de la voie de signalisation de la Src kinase c-Yes et de son partenaire, le co-activateur transcriptionnel YAP. Sous traitement, les cellules chimiorésistantes entrent en quiescence, le complexe protéique entre c-Yes et YAP est perdu et la quantité totale et nucléaire de YAP diminue de manière significative (Igoudjil, Touil, Corvaisier et al. 2014 Clinical Cancer Research). Dès lors, la suite des travaux a consisté en l'étude du rôle potentiel de YAP sur la balance quiescence/prolifération sous 5FU. L'inhibition pharmacologique ou l'inhibition transitoire de l'expression de YAP et de son paralogue, la protéine TAZ, dans plusieurs lignées cancéreuses coliques induit l'augmentation de la fraction de cellules quiescentes, associée au ralentissement significatif de la croissance tumorale. A l'inverse, la surexpression d'une forme constitutivement active de YAP demeurant nucléaire sous 5FU maintient les cellules 5F31 en prolifération et sensibilise les cellules à la chimiothérapie. Au niveau des effecteurs protéiques, l'induction de quiescence (par traitement à la chimiothérapie ou inhibition de YAP/TAZ) est associée à la perte d'expression de la Cycline E1 et du facteur de transcription c-Myc. A l'inverse, la surexpression du dominant constitutivement actif de YAP dans les cellules 5F31 conduit à l'expression soutenue de la Cycline E1 sous 5FU, expression nécessitant l'activation du facteur de transcription CREB. L'inhibition de la Cycline E1 permet d'induire la quiescence cellulaire, proposant cette protéine comme l'un des effecteurs des protéines YAP/TAZ dans la régulation entre la quiescence et la prolifération cellulaire (Corvaisier et al, Oncotarget, 2016). En conclusion, nos données montrent l'importance du rôle des protéines YAP/TAZ dans le maintien des cellules en prolifération via l'expression notamment de la Cycline E1. Nos résultats sur cohorte de patients atteints de métastases hépatiques de cancers colorectaux montrent que l'expression des co-activateurs YAP/TAZ est liée à un index prolifératif plus important, confortant nos données sur le rôle de ces protéines dans la croissance tumorale. De plus, l'expression élevée de YAP et TAZ est associée en analyses multivariées à une récidive plus précoce et à une survie globale plus faible. Ainsi, l'étude de l'expression et du niveau d'activation de ces acteurs serait un marqueur pronostic intéressant dans l'anticipation de la récidive métastatique ; ainsi que des cibles thérapeutiques intéressantes pour tenter de limiter la rechute tumoraleColorectal cancer is the most frequent and lethal cancerous pathology from the digestive system. Each year in France, 41 000 new cases are diagnosed and 17 000 patients die due to this pathology. This high mortality is mainly due to the rate of patients with liver metastatic lesions and the early relapse of those metastases after treatment. The use of chemotherapy prior to surgery induces a decrease of early relapse, however 2 years after resection this advantage is lost. Thus, understanding the mechanisms underlying escape to treatment is required to try to delay or prevent tumor recurrence.The aim of this doctoral work was to analyze clonal chemoresistant subpopulations derived from the colorectal cancer cell line HT29 after chronic exposure to 5-Fluorouracil (5FU) and molecular mechanisms associated with chemoresistance. The most chemoresistant clonal subpopulation, 5F31, stops its proliferation after treatment with high dose of 5FU, this behavior being associated with the modulation of the c-Yes/YAP axis. After treatment, 5F31 cells enter quiescence, interaction between c-Yes and YAP is lost and total and nuclear YAP protein expression reduces significantly (Igoudjil, Touil, Corvaisier et al. 2014, Clinical Cancer Research). The next step was to study functions of YAP protein in this chemotherapy- induced quiescence.Pharmacological or transient inhibition of YAP and its homolog TAZ, induces quiescence and reduces cellular growth in several colorectal cancer cell lines. On the other hand, overexpression of a constitutively active form of YAP in 5F31 cells forces cells to remain proliferative under 5FU treatment, enhancing 5F31 cell chemosensitivity to 5FU.Regarding proteic effectors, quiescence (either induced by 5FU or YAP/TAZ inhibition) is associated with loss of expression of the transcription factor c-Myc and Cyclin E1. In 5F31 cells expressing the active mutant form of YAP, Cyclin E1 expression is sustained after 5FU treatment through the activation of the transcription factor CREB. Cyclin E1 inhibition is sufficient to induce quiescence, therefore introducing this protein as one of the final effectors of YAP/TAZ co-activators in the regulation of the proliferation/quiescence switch in colorectal cancer cells (Corvaisier et al. 2016, Oncotarget).To conclude, our work reveals the importance of YAP/TAZ proteins for the maintenance of colorectal cancer cells proliferation through Cyclin E1 expression. Our work on liver metastases from patients with colorectal cancer shows that high expression of YAP/TAZ is connected to a higher proliferative index in metastatic lesions. Moreover, high YAP/TAZ expression is associated with shorter patient progression-free survival and shorter overall survival. Studying the expression and level of YAP/TAZ activation could be an interesting prognosis marker to anticipate metastatic relapse and potent druggable target to delay tumoral recurrence
8
Harms, Christoph Friedemann. "Endogene Systeme der Neuroprotektion." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2003. http://dx.doi.org/10.18452/14874.
Full textAbstract:
Die Wirkung von zwei endogen neuroprotektiven Substanzen, Melatonin und 17 beta-Estradiol wurde an drei Caspase-abhängigen, apoptotischen, aber Exzitotoxin-unabhängigen Schadensmodellen an neuronalen Primärkulturen untersucht und mit der bei vorwiegend nekrotischen Schadensmodellen verglichen. Es zeigten sich eine Abhängigkeit des neuroprotektiven Potentials von der Art des Zelluntergangs sowie unterschiedliche Mechanismen der Neuroprotektion. Melatonin wirkte in allen drei apoptischen Modellen nicht neuroprotektiv, sondern verstärkte die Schädigung der Neurone noch, während partiell gegen die OGD-induzierte Nekrose (OGD, engl. Oxygen glucose deprivation, kombinierter Sauerstoff- und Glukoseentzug) kortikaler Neurone Schutz erzielt wurde. Der Einsatz des endogenen neuroprotektiven Faktors Melatonin als Therapeutikum ist möglicherweise nur bei neurodegenerativen Erkrankungen mit exzitotoxischer Schädigung durch Glutamat oder oxidativem Stress wie bei Epilepsie oder dem Schlaganfall durch Ischämie sinnvoll. Die fehlende bzw. potenzierenden Wirkung von Melatonin bei neuronaler Apoptose in vitro, stellt jedoch einen therapeutischen Erfolg bei der Behandlung der mit apoptotischer Schädigung einhergehenden Alzheimer'schen Erkrankung in Frage. Bei klinischer Anwendung ist auch der von uns erhobene Befund zu beachten, dass in vitro native neuronale Zellen durch Melatonin geschädigt werden. 17 beta-Estradiol wirkte sowohl bei nekrotischer als auch bei apoptotischer Zellschädigung. Dabei zeigten sich wesentliche Unterschiede in den Mechanismen der Neuroprotektion und in der Ansprechbarkeit verschiedener Regionen des Gehirns. Schutz vor Apoptose konnte nur durch eine Langzeitvorbehandlung (20 h) in septalen und hippokampalen Kulturen, nicht jedoch in kortikalen Kulturen beobachtet werden. Dieser Effekt liess sich durch Rezeptorantagonisten, Proteinsynthesehemmung sowie durch Hemmung der Phosphoinositol-3-Kinase blockieren. Eine Kurzzeitbehandlung war gegen Apoptose nicht wirksam, zeigte gegen OGD und Glutamattoxizität jedoch neuroprotektives Potential. Dieser Effekt liess sich nicht antagonisieren, so dass hier ein direkter antioxidativer Mechanismus wahrscheinlich erscheint. Die antiapoptotische Wirkung in septalen und hippokampalen Kulturen korrelierte mit einer höheren Dichte des Estrogenrezeptors-alpha und einer erhöhten Expression antiapoptotischer Proteine in diesen Regionen. Da bei der Alzheimer'schen Erkrankung der Kortex betroffen ist, könnte der fehlende Effekt von 17 beta-Estradiol in kortikalen Neuronen sowohl auf die neuronale Apoptose als auch auf die Proteinexpression von Bcl-2 und Bcl-xL möglicherweise auf experimenteller Basis erklären, warum eine langfristige Estrogentherapie bei Frauen mit milder bis moderater Alzeimer'scher Erkrankung den Progress der Erkrankung nicht aufhalten konnte (Mulnard et al. 2000).The neuroprotective effect of melatonin and 17 beta-estradiol has been evaluated in several in vitro models of neuronal apoptosis and necrosis. Melatonin was not neuroprotective in three models of apoptosis but showed a pro-apoptotic effect in primary cortical neurons. Melatonin revealed to damage naïve neurons, too. Partial protection was observed against necrotic neurodegeneration after oxygen-glucose deprivation (OGD). The use of melatonin as a therapeutic agent might be of interest in neurodegenerative diseases with excitotoxic damage like epilepsia or ischemia, but is questioned in case of apoptotic neurodegeneration. 17 beta-estradiol was neuroprotectiv in both necrotic and apoptotic neurodegeneration. Differences in the mechanism of neuroprotetion and in the efficacy in different regions of the brain were observed. A neuroprotective effect was visible only in hippocampal and septal cultures if 17 beta-estradiol was applied 20 h prior (long term pre-treatment) but not in cortical neurons. This effect correlates with an increased density of estrogen receptor-alpha and an increased expression of anti-apoptotic proteins like Bcl-2 and Bcl-xL in these regions. These effect could be blocked with receptor antagonists, protein synthesis inhibitors and an inhibitor of the phosphatidylinositol 3-kinase. A short term pre-treatment revealed a receptor independent neuroprotective potential against OGD and glutamate toxicity. The failure of 17 beta-estradiol to protect cortical neurons against apoptosis could be an experimental basis to understand, why a long lasting treatment with estrogens of women with mild to moderate Alzheimer´s disease failed to inhibit the progress of the illness (Mulnard et al., 2000)
9
Masin, Marianela. "Identification and characterization of the molecular complex formed by the P2X2 receptor subunit and the adapter protein Fe65 in rat brain." Doctoral thesis, 2006. http://hdl.handle.net/11858/00-1735-0000-0006-B6DE-2.
Full text
10
Jürgens, Daniel. "Untersuchung der elektrischen Hyperfeinwechselwirkung in Mn+1AXn-Phasen mittels der gestörten γ-γ-Winkelkorrelation." Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0022-5EB8-2.
Full textAbstract:
Mn+1AXn-Phasen sind thermodynamisch stabile nanolaminierte Ternärcarbide und -nitride, die sowohl metallische als auch keramische Eigenschaften aufweisen. Der Buchstabe M steht für ein frühes Übergangsmetall, der Buchstabe A für ein A-Element aus den Gruppen IIIA – VIA und X für Kohlenstoff und/oder Stickstoff. Die M-Atome bilden Oktaederschichten mit X-Atomen in ihren Zentren. Der Index n beschreibt die Dicke der Mn+1Xn-Lage, die zwischen zwei hexagonalen A-Schichten eingebettet ist. Die außergewöhnlichen Eigenschaften dieser Materialien haben ihren Ursprung in ihrer Mikrostruktur. Um einen Einblick auf atomarer Ebene zu gewinnen wird die Messmethode der gestörten γ-γ-Winkelkorrelation (PAC) angewendet. Die radioaktiven Sonden 111In/111Cd und 181Hf/181Ta werden durch Ionenimplantation und/oder durch Neutronenaktivierung in das Wirtsmaterial eingebracht, um den elektrischen Feldgradienten (EFG) zu messen, der am Gitterpatz des Sondenatoms herrscht.
Das erste Ziel der Arbeit ist die Suche nach optimalen Ausheilparametern, mit denen ein möglichst hoher Anteil der Sonden die gleiche lokale Umgebung spürt. Der nächste Schritt ist die Bestimmung des Gitterplatzes der Sonden in der MAX-Struktur. Als Ergebnis kann festgestellt werden, dass 111In in den In- und Al-basierten MAX-Phasen fast ausschließlich den A-Platz besetzt, während 181Hf in Hf2InC auf dem M-Platz eingebaut wird. Als überraschendes Ergebnis zeigt diese Arbeit, dass die PAC-Methode bei Phasen mit gleichen Konstituenten, aber unterschiedlicher Mn+1Xn-Schichtdicke sensitiv auf die Änderung der Stapelfolge ist.
Die Experimente werden mit umfangreichen Rechnungen auf Basis der Dichtefunktionaltheorie (DFT) verglichen, die hier erstmalig für nahezu alle Mitglieder der Familie der MAX-Verbindungen durchgeführt wurden. Die DFT-Rechnungen reproduzieren die gemessenen EFGs mit hoher quantitativer Genauigkeit und stützen die Hypothese, dass sich die Sonden auf den prognostizierten Gitterplätzen befinden.
Books on the topic "WW 2"
1
Kachmar, Paul Elliot. WW-II 1/2. New York: Vantage Press, 2002.
Find full text
2
Sheets, John L. 745 survivor WW-2: Combat infantry rifleman. Gallipolis, OH: J.L. Sheets, 2000.
Find full text
3
Drabkin, Artem. Red Army infantrymen remember the Great Patriotic War: A collection of interviews with 16 Soviet WW-2 veterans. Bloomington, IN: AuthorHouse, 2009.
Find full text
4
Drabkin, Artem. Red Army infantrymen remember the Great Patriotic War: A collection of interviews with 16 Soviet WW-2 veterans. Bloomington, IN: AuthorHouse, 2009.
Find full text
5
Pictorial HIST WW 2. Main Street Books, 1990.
Find full text
6
Casterson, Scott. Short History WW 2. Lulu Press, Inc., 2016.
Find full text
7
Kachmer, Paul Elliott. WW II 1/2. Vantage Pr, 2002.
Find full text
8
Ww Iii:behind Lin Nuk (Ww III : Behind the Lines, Book 2). Berkley, 1990.
Find full text
9
Cd-Rom, 1. Starhawks 2 C/D&W/Ww. N-TK ENTERTAINMENT, 1996.
Find full text
10
Publishing, RH Value. War Planes & Air Battles WW 2. Crescent, 1988.
Find full textBook chapters on the topic "WW 2"
1
"2 Water into Wine (= WW)." In Lady E. S. Drower's Scholarly Correspondence, 73–133. BRILL, 2012. http://dx.doi.org/10.1163/9789004222472_004.
Full text
2
"PP P PP aa a aa rr r rr tt t tt tt t tt ww w ww oo o oo." In Routledge Philosophy GuideBook to Plato and the Republic, 41–204. Routledge, 2002. http://dx.doi.org/10.4324/9780203069813-2.
Full textConference papers on the topic "WW 2"
1
Angelos, Mathew G., Elise C. Kohn, and Andrea K. McCollum. "Abstract LB-190: Novel cell cycle regulation through the WW-domain of the co-chaperone BAG3." In Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL. American Association for Cancer Research, 2011. http://dx.doi.org/10.1158/1538-7445.am2011-lb-190.
Full text
2
Hill, Steven C. "Modeling nonlinear optics in microdroplets." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1993. http://dx.doi.org/10.1364/oam.1993.ww.2.
Full textAbstract:
Nonlinear mixing processes such as coherent anti-Stokes Raman scattering (CARS),1 and third-order sum-frequency generation (TSFG)2 have been modeled in microdroplets. The radiation from the third-order nonlinear polarization is modified by the spherical cavity. When the input waves are Gaussian beams tightly-focused near the center of the droplet, the morphology-dependent resonances (MDRs) are not excited, and the phase matching analysis is similar to that in bulk materials (the bending of the beams at the droplet surface must be considered). CARS generated by such focused beams may be useful for probing the spatially-dependent internal species concentrations. When the generating waves are focused at the edge of the droplet, or when the generating waves have been generated inside the droplet by a nonlinear process (e.g., stimulated Raman scattering in the case of TSFG), then the output intensity is very sensitive to droplet size, and to the spatial and frequency overlaps between the MDRs. Intensity-dependent shifts in MDR frequencies, and effects of two-photon on time-dependent scattering have also been modeled.3
3
McCollum, Andrea K., Mathew G. Angelos, Andrea D. Fischione, Marco Mineo, and Elise C. Kohn. "Abstract 2032: A novel function of WW domain binding protein 2 (WBP2) in regulating cytoskeletal function and cellular division through binding to co-chaperone BAG3." In Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL. American Association for Cancer Research, 2012. http://dx.doi.org/10.1158/1538-7445.am2012-2032.
Full text
4
Cadirci, Sertac, and Hasan Gunes. "Boundary Layer Separation Control on an Inclined Plate Using Jet and Vortex Actuator." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62551.
Full textAbstract:
In this numerical study a Jet and Vortex Actuator (JaVA) system is implemented on an inclined plate (with an inclination angle 6°) to control the laminar boundary layer separation. JaVA is an active flow control device similar to the synthetic jets that transports momentum into the boundary layer and interacts with the boundary layer velocity profiles. The JaVA used in this study is a two-dimensional rectangular cavity with an actuating plate mounted on the opening which is placed asymmetrically. The plate moves up and down in vertical direction with a specified frequency. As the actuating plate is mounted asymmetrically on the cavity-opening, there are one narrow (wn) and one wide gap (ww) between the plate and the cavity. First JaVA in a cross-flow on an inclined plate (with inclination angle 6°) is modeled using a computational domain including a moving zone to mimic the vertical motion of the actuating plate. As plate moves up and down like a piston, JaVA-induced vortices emanate from the wide gap and are injected into the oncoming boundary layer. The calculations are carried out by a commercial finite-volume-based unsteady, laminar, incompressible Navier-Stokes solver. Time-averaged flow fields are calculated to extract boundary layer profiles from various downstream stations. For different oscillation frequencies (f = 1, 2, 3 and 4 Hz) time averaged boundary layers are compared to the non-actuated case (f = 0). The variations of the important boundary layer characteristics (displacement thickness, momentum thickness, shape factor) as well as friction coefficient are also investigated. It is observed that with increasing plate frequency or jet-Reynolds number (ReJ = 4abf/ν), JaVA-induced vortices interact with the cross-flow and modify the boundary layer characteristics. This has been shown in the time-averaged velocity profiles with a fuller shape causing larger displacement thicknesses and in association with them the shape factors drop and the friction coefficients increase. The proposed control method based on alternating suction and blowing with an oscillating plate is effective in delaying or preventing the flow separation downstream of an inclined plate.
5
Kondo, Taisei, Mikihito Otani, Takako Sinzi, Megumi Aibara, Kiyoshi Kurakawa, Kazumi Sekiguchi, Atsushi Kobayashi, Aiko Takazawa, and Masakazu Furuichi. "Life History Support System “LHS” - Recording Memories and Sharing Stories for Family Social Network." In AHFE 2023 Hawaii Edition. AHFE International, 2023. http://dx.doi.org/10.54941/ahfe1004376.
Full textAbstract:
The world is aging rapidly, and the population of over 65 years old in Japan is 29.1% (Sep. 15, 2022, Japan Statistic Bureau of Japan), which is the highest in Japanese history. Human memory and knowledge are rapidly being digitized on an incalculable scale. While its value as a booster for monetization is now known worldwide, such private and personal heritage, especially its whereabouts remains unknown. In particular, the memory and knowledge of elders are not recorded appropriately for the next generations, we claim that the current system has shown an enormous loss of value in society, especially for the family members. Therefore, the desire to interview and document the life experiences of different generations of family members is very important. However, interviewing and documenting are difficult to achieve for various reasons, in such cases as when family members live apart from each other. Therefore, our research group has started to develop Life History Support System called “LHS”. The new system aims to solve the problem and preserve elderlies' wisdom and knowledge cultivated in turbulent times, such as during WW II and the post-war years of recovery. The LHS is designed for the Family Social Network, allowing digital information to be accessed only by the same members. LHS is an application that runs on smartphones, tablets and PC which is connected to the Internet and works as a social network system (SNS), but the main difference between conventional SNS is (1) LHS can be accessed only by the family members or designated members, (2) it mainly works as a card type database to share topic cards among members. We have developed a prototype system using Apple’s Claris FileMaker database system which runs on-premises private server. Then, to test the prototype's applicability, we have performed a preliminary interview experiment in an actual user environment (family members living together or living apart, and the elderly person living alone). The result shows that we could identified the experience of “fun” by both, an interviewer and interviewee, during the process of recall of memories with the LHS setup. Rather, we confirm the needs in longitudinal study to capture the continuous use of the LHS. Since the LHS inherently gains its value by long-term regular use, interviewing, recording and viewing by many family members, it is necessary to add new functions based on some theories. We are planning to include gamification functions to LHS. This paper describes the LHS system overview and the current development status.
Reports on the topic "WW 2"
1
Litaor, Iggy, James Ippolito, Iris Zohar, and Michael Massey. Phosphorus capture recycling and utilization for sustainable agriculture using Al/organic composite water treatment residuals. United States Department of Agriculture, January 2015. http://dx.doi.org/10.32747/2015.7600037.bard.
Full textAbstract:
Objectives: 1) develop a thorough understanding of the sorption mechanisms of Pi and Po onto the Al/O- WTR; 2) determine the breakthrough range of the composite Al/O-WTR during P capturing from agro- wastewaters; and 3) critically evaluate the performance of the composite Al/O-WTR as a fertilizer using selected plants grown in lysimeters and test-field studies. Instead of lysimeters we used pots (Israel) and one- liter cone-tainers (USA). We conducted one field study but in spite of major pretreatments the soils still exhibited high enough P from previous experiments so no differences between control and P additions were noticeable. Due to time constrains the field study was discontinued. Background: Phosphorous, a non-renewable resource, has been applied extensively in fields to increase crop yield, yet consequently has increased the potential of waterway eutrophication. Our proposal impetus is the need to develop an innovative method of P capturing, recycling and reuse that will sustain agricultural productivity while concurrently reducing the level of P discharge from and to agricultural settings. Major Conclusions & Achievements: An innovative approach was developed for P removal from soil leachate, dairy wastewater (Israel), and swine effluents (USA) using Al-based water treatment residuals (Al- WTR) to create an organic-Al-WTR composite (Al/O-WTR), potentially capable of serving as a P fertilizer source. The Al-WTR removed 95% inorganic-P, 80% to 99.9% organic P, and over 60% dissolved organic carbon from the agro-industrial waste streams. Organic C accumulation on particles surfaces possibly enhanced weak P bonding and facilitated P desorption. Analysis by scanning electron microscope (SEM- EDS), indicated that P was sparsely sorbed on both calcic and Al (hydr)oxide surfaces. Sorption of P onto WW-Al/O-WTR was reversible due to weak Ca-P and Al-P bonds induced by the slight alkaline nature and in the presence of organic moieties. Synchrotron-based microfocused X-ray fluorescence (micro-XRF) spectrometry, bulk P K-edge X-ray absorption near edge structure spectroscopy (XANES), and P K-edge micro-XANES spectroscopy indicated that adsorption was the primary P retention mechanism in the Al- WTR materials. However, distinct apatite- or octocalciumphosphatelike P grains were also observed. Synchrotron micro-XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al-WTR aggregates. Organic P species were not explicitly identified via P K-edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. In screen houses experiments (Israel) we showed that the highest additions of Al/O-WTR (5 and 7 g kg⁻¹) produced the highest lettuce (Lactuca sativa L. var. longifolial) yield. Lettuce yield and P concentration were similar across treatments, indicating that Al/O- WTR can provide sufficient P to perform similarly to common fertilizers. A greenhouse study (USA) was utilized to compare increasing rates of swine wastewater derived Al/O-WTR and inorganic P fertilizer (both applied at 33.6, 67.3, and 134.5 kg P₂O₅ ha⁻¹) to supply plant-available P to spring wheat (TriticumaestivumL.) in either sandy loam or sandy clay loam soil. Spring wheat straw and grain P uptake were comparable across all treatments in the sandy loam, while Al/O-WTR application to the sandy clay loam reduced straw and grain P uptake. The Al/O-WTR did not affect soil organic P concentrations, but did increase phosphatase activity in both soils; this suggests that Al/O-WTR application stimulated microorganisms and enhance the extent to which microbial communities can mineralize Al/O-WTR-bound organic P. Implications: Overall, results suggest that creating a new P fertilizer from Al-WTR and agro-industrial waste sources may be a feasible alternative to mining inorganic P fertilizer sources, while protecting the environment from unnecessary waste disposal.