95 research outputs found
Development of a Displacement-Based Design Method for Steel Dual Systems With Buckling-Restrained Braces and Moment-Resisting Frames
No full textDual systems can offer an attractive lateral force-resisting solution, combining individual systems in a
complementary manner. A displacement based-design (DBD) method is proposed for steel dual
systems incorporating moment-resisting frames (MRFs) and buckling-restrained braces (BRBs). The
validity of the method is established through a verification study considering theoretical designs of 6-,
9-, 12-, and 18-story buildings and nonlinear time-history analysis (NTHA) using ten spectrum
compatible accelerograms. The results show that the DBD method provides good control of displacements
and drifts for the structures, although higher mode effects tend to become significant for the taller
case studies. In addition to controlling peak deformations, the article illustrates how the inclusion of the
MRFs in parallel to BRB systems can be an effective means of limiting residual deformations
Ten years of conflict management research 2007-2017
No full textPurpose: The purpose of this study is to map the intellectual structure of conflict management studies by investigating the key themes, concepts and their relationships for the period 2007-2017. The study updates the previous decade (1997-2006) investigation by Ma et al. (2008) to reflect the increased publication efforts in the field. Design/methodology/approach: Bibliometric analysis was used to trace the development path of the extant literature. The study included activity indicators such as distribution of articles and most-cited journals; relationship indicators such as co-author analysis and keyword analysis; and the mapping of the theoretical foundations. Findings: The analysis identified five key themes that help track the direction of conflict management research: negotiation, mediation, trust, conflict management styles and performance. Originality/value: These themes show a wider diversification of topics in the field than in the past, corroborating previous results about the reputation and maturity of conflict management as an independent scientific field of research. This study will help scholars to improve their understanding of the evolution of conflict management studies and the direction that conflict management research is taking, in particular, identifying available avenues for future research
Maley, Timothy (Death, 1879-08-05)
No full textAddress: 170 W. Front St.Age at death: 81 yrsPg 82/1879/94/M W M/Ireland/Dr. C. Brent/J Sullivan/St. Joseph's NewOriginal record filed in drawer labeled 'MAIN-MANNING'
Tissue engineering of a tracheal substitute
No full textLectin histochemistry and scanning electron microscopy (SEM) was used to assess the growth and characterise the differentiation of human respiratory epithelial cells (REC) cultured on two biomaterial scaffolds. The first scaffold, based on a hyaluronic acid derivative, was observed to be non-adhesive for REC. This lack of adhesion was found to be unrelated to the presence of the hyaluronic acid binding domain on the surface of isolated REC. The other scaffold, consisting of equine collagen, was observed to encourage REC spreading and adhesion. Positive Ulex Europaeus agglutinin (UEA) lectin staining of this preparation indicated the presence of ciliated REC on the scaffold surface. However, the marked decrease in peanut agglutinin (PNA) positive staining, relative to that of control cultures and native tissue, indicates a dedifferentiation of the secretory cells in monolayer. SEM analysis of REC cultured on the collagen scaffold confirmed the presence of ciliated cells thereby validating the UEA positive staining. The presence of both established and developing cilia was also verified. This indicates that collagen biomaterials are appropriate for the tissue engineering of REC. Furthermore, that UEA and PNA staining is a useful tool in the characterisation of cells cultured on biomaterials, therefore helpful in identifying biomaterials that are suitable for specific tissue engineering purposes.
The culture of REC at an air liquid interface (ALI) was investigated. Both conventional ALI inserts and the Biofleece scaffold were used. The cells grown the on conventional inserts became multilayered and showed some degree of ciliation after the period of ten days. The cells grown on the Biofleece scaffold became necrotic and died due to nutrient deprivation. The use of ALI culture techniques on scaffold materials needs to be adjusted to allow for sufficient nutrient supply to the cells.
The Biofleece scaffold was found to be suitable for the tissue engineering of cartilage in vitro. Constructs with a cartilage-like morphology were generated with the scaffold after two weeks in culture. The tissue-engineered cartilage was found to contain a higher number of cells and less extracellular matrix (ECM) than the native tissue controls. Suction seeding techniques were used to improve the distribution of cells within the scaffold and thereby increase the overall efficiency of cartilage tissue engineering within the scaffold. Alcian blue (AB) and Papanicolau (PN) stains of the tissue engineered cartilage described two distinct regions within the constructs, namely the developed cartilage-like region and the developing region. The latter is thought to be areas in which the cartilage cells are yet to fully remodel the scaffold material and deposit their own “native” ECM. However, the Biofleece scaffold material was observed to loose 40-50% of its initial volume during the tissue engineering process over a period of two weeks. Thus the degradation of the Biofleece scaffold exceeds the rate of maturation of the cartilage tissue within the scaffold. This rapid biodegradation is most likely a result of matrixmetalloproteinase (MMP), in particular collagenase, production by the maturing chondrocytes. This reduction in size means that the Biofleece scaffold is not an appropriate material for the tissue engineering of a trachea. The optimal biomaterial for the tissue engineering of a trachea would degrade at a rate equal too, or slower than, the time taken for the cells within the scaffold to mature into functional tissue.
The co-culture of REC and chondrocytes was achieved through the use of matrigel as a basement membrane replacement (note that direct growth of REC on cartilage tissue has been observed to be difficult). The co-cultured constructs were not stable because the Biofleece scaffold degrades at a high rate in the presence of both cell types. The constructs were observed to shrink to approximately 35-30% of the original dimensions in a period of 3-7 days. The reason for this accelerated degradation is not known but is most likely the result of severe MMP production by the two cell types when in combination.
It was concluded that the characterisation procedures used in this study (histochemical staining, fluorescent staining and scanning electron microscopy) for both REC and chondrocyte tissue engineered constructs are appropriate for this and further studies. The chondrocyte seeding methodologies in particular are a useful tool for tissue engineering. This study succeeds in many ways to investigate the tissue engineering of a tracheal substitute by detailing how REC and chondrocytes can be cultured on biomaterials and assessed for tissue development. However, the study does not deliver such a viable substitute as an end product. The primary reason for this outcome is the rapid degradation of the Biofleece scaffold materialLectin Histochemie und Elektronenmikroskopie wurden benutzt, um das Wachstum von humanen respiratorischen Epithelzellen (RECs), welche auf zwei Biomaterialien kultiviert wurden, festzusetzen und ihren Differenzierungsgrad zu bestimmen. Das erste Trägermaterial, welches auf einem Hyaluronsäurederivat basiert, ließ keine Anheftung der RECs zu. Diese fehlende Anheftung ließ sich jedoch nicht zurückführen auf das Vorhandensein der Hyaluronsäure bindenden Domaine auf der Oberfläche isolierter RECs. Das andere Trägermaterial, aus Pferdekollagen hergestellt, zeigte dagegen eine verstärkte Teilungsaktivität und Anheftung der REC. Die positive Ulex Europaeus Agglutinin (UEA) Lectin Färbung dieser Proben ließ die Anwesenheit von mit Zilien versehenen RECs auf der Trägerstoffoberfläche vermuten. Darüber hinaus weist das im Vergleich zu Kontrollkulturen und nativem Gewebe deutliche Nachlassen der positiven Peanut Agglutinin–Färbereaktion auf eine Dedifferenzierung der sekretorischen Zellen in der Monolayer-Kultur hin. Die rasterelektronenmikroskopische Untersuchung der auf dem Kollagenbiomaterial kultivierten RECs bestätigte das Auftreten von Zellen mit Zilien und damit auch die Aussagekräftigkeit der positiven UEA–Färbung. Dies zeigt somit, dass Biomaterialien aus Kollagen für das Tissue Engineering von RECs geeignet sind und dass sowohl die UEA–als auch die PNA–Färbung geeignete Methoden zur Charakterisierung von Zellen darstellen, die auf Biomaterialien kultiviert wurden. Somit helfen sie bei der Identifizierung von Biomaterialien für bestimmte Einsatzgebiete im Tissue Engineering.
Des weiteren wurde die Kultivierung von RECs auf einem Air liquid interface (ALI) untersucht, wobei sowohl der konventionelle ALI–Einsatz als auch das Biovliesmaterial zum Einsatz kamen. Dabei wuchsen die Zellen auf dem konventionellen Einsatz in Multilayern und zeigten nach einem Zeitraum von 10 Tagen einen bestimmten Anteil an Ziliierung. Die Zellen auf dem Biovlies dagegen wurden nekrotisch und gingen schließlich an Nahrungsmangel ein. Deshalb muss der Einsatz von ALI–Kulturtechniken bei Trägermaterialien dementsprechend modifiziert werden, dass eine ausreichende Versorgung der Zellen mit Nährstoffen gewährleistet ist.
Für das in vitro–Tissue Engineering von Knorpel erwies sich das Biovlies jedoch als geeignet. Mit ihm konnten nach zwei Wochen Kulturzeit Konstrukte mit einer knorpelähnlichen Morphologie erzeugt werden. Dabei zeigte sich, dass der Tissue Engineering–Knorpel eine höhere Zellzahl bei reduzierter extrazellulärer Matrix (ECM) aufwies als vergleichbares natives Kontrollgewebe. Dabei wurden Saugtechniken benutzt, um die Verteilung der Zellen im Trägerstoff zu verbessern. Die Alzian – Blau – Färbung (AB) und Papanicolau – Färbung (PN) zeigten bei dem Tissue Engineering–Knorpel zwei unterschiedliche Regionen innerhalb des Konstrukts, nämlich eine knorpelähnliche bereits entwickelte Region und eine sich entwickelnde Region. Bei letzterer dürfte es sich wohl um Gebiete handeln, in denen Zellen noch im Begriff sind, den Trägerstoff vollends umzubauen und ihre eigene „native“ ECM abzulagern. Nichtsdestoweniger büßte das Biovlies während des Tissue Engineering Prozesses über einen Zeitraum von zwei Wochen annähernd 40-50 % seines anfänglichen Volumens ein. Somit übersteigt das Ausmaß der Degradation des Biovlieses das des Heranreifens von Knorpelgewebe in dem Trägermaterial. Diese schnelle Biodegradation ist am ehesten das Ergebnis der Aktivität von Matrixmetalloproteinasen (MMP), insbesondere der Kollagenase, welche von reifenden Chondrozyten produziert wird. Diese Schrumpfung bedeutet also, dass das Biovlies kein geeignetes Material für das Tissue Engineering der Trachea darstellt. Denn ein optimales Biomaterial für das Tissue Engineering der Trachea sollte sich innerhalb derselben Zeit bzw. über einen längeren Zeitraum hinweg abbauen, als innerhalb desjenigen, den die sich in dem Trägermaterial befindlichen Zellen benötigen, um zu funktionalem Gewebe heranzureifen.
Durch den Einsatz von Matrigel als Ersatz für die Basalmembran konnte eine Kokultur aus RECs und Chondrozyten etabliert werden (wobei anzumerken ist, dass sich direktes Wachstum von RECs auf Knorpelgewebe als problematisch erweist). Die Konstrukte aus Kokulturen waren nicht stabil, da das Biovlies in Anwesenheit beider Zelltypen hochgradig abgebaut wird. Innerhalb von 3–7 Tagen schrumpften die Konstrukte auf ca. 35–50 % ihrer Ausgangsgröße zusammen. Der Grund für diesen beschleunigten Abbau ist unbekannt, jedoch ist am ehesten eine ausgeprägte Produktion von MMP durch die beiden Zellarten anzunehmen, sobald diese in Kombination vorliegen.
Insgesamt lässt sich sagen, dass die Methoden zur Zell- und Gewebecharakterisierung, welche in dieser Studie benutzt wurden (histochemische Färbungen, Fluoreszenzfärbung und Elektronenmikroskopie) sowohl für mit RECs als auch mit Chondrozyten hergestellte Konstrukte für die vorliegende Arbeit als auch zukünftige Studien als geeignet anzusehen sind. Diese Studie hat in vielerlei Hinsicht erfolgreich das Tissue Engineering einer Luftröhre untersuchen können, indem sie im Detail aufzeigt, wie RECs und Chondrozyten auf Biomaterialien kultiviert und für das Tissue Engineering eingesetzt werden können. Trotzdem kann diese Arbeit kein einsetzbares Ersatzmaterial als Endprodukt liefern. Der Hauptgrund für dieses Ergebnis ist in erster Linie in dem schnellen Abbau des Biovlieses als Trägermaterial zu sehen
Spenser and Shakespeare: Bards of a feather?
No full textThis chapter examines the latticework of links between Shakespeare and Spenser, sifting the available evidence to establish key points of contact within the Irish colonial context. It tells a tale of two writers, one who goes to London to become poet and playwright, the other to Dublin with dreams of a dramatic career, where he finds his theatre of worldlings is a theatre of war. If Spenser’s influence on Shakespeare, especially early Shakespeare, is seldom discussed, Shakespeare’s influence on Spenser remains an even more neglected topic. Shifting from an Anglocentric to an Anglo-Irish focus aids our understanding of the creative context from which Shakespeare took wing. Spenser is crucial here, since that poet’s Irish residence necessitates a broadening of horizons, and he is viewed as part of a recognizable circle. Shakespeare was a lifelong co-author and collaborator influenced by several of Spenser’s Irish contemporaries – Lodowick Bryskett, Geoffrey Fenton, Barnabe Googe, Thomas North, Barnaby Rich, and Petruccio Ubaldini – yet he is more often read in isolation. These writers and translators, part of an expansive English literary circle in Ireland, offer a rich resource for understanding and enhancing the ‘Shakespeare Circle’ that has recently received some critical attention, albeit within a restricted English milieu. From the Spenser-Harvey correspondence and the early histories onwards, this study tracks the collaborative underpinnings of both writers’ work, charting their influences from a shared reliance on Holinshed to a common concern with innovation in form and genre
Holocene changes in African vegetation: Tradeoff between climate and water availability
No full textAlthough past climate change is well documented in West Africa through instrumental records, modeling activities, and paleo-data, little is known about regional-scale ecosystem vulnerability and long-term impacts of climate on plant distribution and biodiversity. Here we use paleohydrological and paleobotanical data to discuss the relation between available surface water, monsoon rainfall and vegetation distribution in West Africa during the Holocene. The individual patterns of plant migration or community shifts in latitude are explained by differences among tolerance limits of species to rainfall amount and seasonality. Using the probability density function methodology, we show here that the widespread development of lakes, wetlands and rivers at the time of the "Green Sahara" played an additional role in forming a network of topographically defined water availability, allowing for tropical plants to migrate north from 15 to 24° N (reached ca. 9 cal ka BP). The analysis of the spatio-temporal changes in biodiversity, through both pollen occurrence and richness, shows that the core of the tropical rainbelt associated with the Intertropical Convergence Zone was centered at 15-20° N during the early Holocene wet period, with comparatively drier/more seasonal climate conditions south of 15° N. © 2014 Author(s)
Dynamic clonal equilibrium and predetermined cancer risk in Barrett's oesophagus
No full textabstract: Surveillance of Barrett’s oesophagus allows us to study the evolutionary dynamics of a human neoplasm over time. Here we use multicolour fluorescence in situ hybridization on brush cytology specimens, from two time points with a median interval of 37 months in 195 non-dysplastic Barrett's patients, and a third time point in a subset of 90 patients at a median interval of 36 months, to study clonal evolution at single-cell resolution. Baseline genetic diversity predicts progression and remains in a stable dynamic equilibrium over time. Clonal expansions are rare, being detected once every 36.8 patient years, and growing at an average rate of 1.58 cm[superscript 2] (95% CI: 0.09–4.06) per year, often involving the p16 locus. This suggests a lack of strong clonal selection in Barrett’s and that the malignant potential of ‘benign’ Barrett’s lesions is predetermined, with important implications for surveillance programs.The final version of this article, as published in Nature Communications, can be viewed online at: https://www.nature.com/articles/ncomms1215
Global talent management and inpatriate social capital building: a status inconsistency perspective
No full textDistinct to expatriate managers at the subsidiary-level, inpatriate managers' influence at the headquarter (HQ)-level is controlled by the extent to which an inpatriate manager is able to ‘win’ status from HQ personnel. The primary goal of the paper is to conceptualize how organizational support, in the form of global talent management (GTM) practices, can alleviate inpatriates' difficulties in building social capital at HQ. Building social capital at HQ is vital for inpatriates to attain status in order to build the inter-unit social capital that enables them to pursue their boundary-spanning role across HQs and subsidiaries. Status inconsistency theory is put forward to recognize the personal, professional and structural incongruence of events and activities at HQ carried out with respect to inpatriates. We argue that inpatriate managers become empowered at HQ only when social capital is accumulated whereby social capital is driven by an acknowledgment of inpatriates as a legitimate staffing option. The relationship between GTM practices and social capital building needs to be managed properly by inpatriates themselves as well as by the organization. A future research agenda helping to build social capital of inpatriates through GTM infrastructure is discussed and propositions are offered throughout
Pollen dataset for "Asymmetric response of forest and grassy biomes to climate variability across the African Humid Period: influenced by anthropogenic disturbance?"
No full textThis dataset is associated with Phelps et al. (2020, DOI: 10.1111/ecog.04990), and is comprised of paleoecological information from African subfossil pollen assemblages over the past 20,000 years. Data includes the following information:
Appendix 1: a list of collated sites from the APD, EPD, and other publications
Appendix 2: a list of collated entities from the APD, EPD, and other publications
Appendix 3: a list of citations for each entity in appendix 2, whether analyzed or not
Appendix 4: a harmonized taxa list with original taxa names and numbers
Appendix 5: a list of collated samples from the APD, EPD, and other publications
Appendix 6: a list of counts from the APD, EPD, ACER, and other publications
Appendix 7: a list of dates (14C, etc) from the APD, EPD, ACER, and other publications
Appendix 8: a list of CLAM outputs calculated (Blaauw 2010) from the list of radiocarbon dates
Appendix 9: a harmonized biomization scheme for "direct" and "indirect" methods
For use of these datasets, associated publications (see appendix 3) and databases should be cited:
The African Pollen Database (APD: Vincens et al. 2007, http://fpd.sedoo.fr/fpd/bibli.do)
The European Pollen Database (EPD: Fyfe et al. 2009, http://www.europeanpollendatabase.net/getdata/)
The ACER Pollen and Charcoal Database (Sánchez Goñi et al. 2017)
Additional information was added to these appendices in association with the following publications (note: information was extracted from publications and/or contributed by authors): Brenac 1988, Burrough & Willis 2015, Chase et al. 2015b, Cheddadi et al. 2015, 2016, 2017, Cordova et al. 2017, Giresse et al. 1994, Lim et al. 2016, Maley 1991, Maley & Brenac 1998, Metwally et al. 2014, Quick et al. 2016, 2018, Valsecchi et al. 2013, Waller et al. 2007. The harmonized biomization scheme (appendix 9), is based on six primary publications: Jolly et al. 1998, Elenga et al. 2000, Vincens et al. 2006, Vincens et al. 2007, Lebamba et al. 2009, Lézine et al. 2009, with reference to the African Plant Database (version 3.4.0)
Demanda de deformación en edificaciones con y sin disipadores de energía
No full text60 páginasEste trabajo tiene como objetivo analizar el comportamiento de la demanda de deformación en estructuras aporticadas de concreto reforzado con y sin disipadores de energía cuando están sometidas a fuerzas sísmicas.PregradoIngeniero(a) Civi
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