Multiphase modelling of the effect of fluid shear stress on cell yield and distribution in a hollow fibre membrane bioreactor

We present a simplified two-dimensional model of fluid flow, nutrient transport and cell distribution in a hollow fibre membrane bioreactor, with the aim of exploring how fluid flow can be used to control the distribution and yield of a cell population which is sensitive to both fluid shear stress and nutrient concentration. The cells are seeded in a scaffold in a layer on top of the hollow fibre, only partially occupying the extracapillary space. Above this layer is a region of free-flowing fluid which we refer to as the upper fluid layer. The flow in the lumen and upper fluid layer is described by the Stokes equations, whilst the flow in the porous fibre membrane is assumed to follow Darcy’s law. Porous mixture theory is used to model the dynamics of and interactions between the cells, scaffold and fluid in the cell–scaffold construct. The concentration of a limiting nutrient (e.g. oxygen) is governed by an advection–reaction–diffusion equation in each region. Through exploitation of the small aspect ratio of each region and asymptotic analysis, we derive a coupled system of partial differential equations for the cell volume fraction and nutrient concentration. We use this model to investigate the effect of mechanotransduction on the distribution and yield of the cell population, by considering cases in which cell proliferation is either enhanced or limited by fluid shear stress and by varying experimentally controllable parameters such as flow rate and cell–scaffold construct thickness

Personal Letter from Charles A. Webb to Dan Tompkins

This letter is part of the Dan Tompkins Collection housed in the special collections library of WCU in box MSS 80-14. It was written to Dan Tompkins from Charles Webb, associate publisher of the Citizen, during the 1920 election in North Carolina. Tompkins was editor of the Jackson County Journal during this time. He also served three terms in the House of Representatives and as the Mayor of Sylva in following years (Austin)

Personal Letter from C.B. Robinson to H.T. Hunter

iiiIntroductionThis letter was written by Jackson County businessman C.B. Robinson to the president of Western Carolina Teacher’s College, H.T. Hunter. In the letter, Robinson discusses the state of Western Carolina Teacher’s College, now Western Carolina University. C.B. Robinson owned Blackwood Lumber Company, a staple of the region’s economy and one of the most booming industries of this period (MSS 16-07.5). The handwritten note at the bottom addressed to Dan Tompkins suggests that Robinson was not only a prominent businessman but also a well-regarded member of the community

Personal Letter from Dan Tompkins to his mother and family

This letter was written by Dan Tompkins to his mother and family, in Sylva, NC, while he was staying in Raleigh for business. As the letter heading reflects, Tompkins was a North Carolina State Representative during this time, thus he would have traveled to Raleigh on political business. In addition to serving three terms in the North Carolina House of Representatives, Tompkins was also the editor of the Jackson County Journal from 1912 to 1943 (Austin)

Form Letter from King George V to Dan Tompkins

This form letter was written by Britain’s King George V to the enlisted American soldiers upon the arrival of United States troops on Europe. King George had declared war on Germany four years earlier, helping set the stage for the battle between the Allies and Central Powers that the U.S. joined in 1917. This letter was received by all American soldiers entering the war and was a treasured souvenir for many soldiers

A new species of Tiaracrinus from the latest Emsian of Morocco and its Phylogeny

Abstract: We describe a new species of the unusual crinoid Tiaracrinus, T. jeanlemenni sp. nov. from the latest Emsian of the famous mudmound locality Hamar Laghdad,Morocco. It differs from the previously known species inthe higher number of ribs and the vaulted rib-fields, which is corroborated by the comparison of simple quantitative characters and ratios as well as by the results of a clusteranalysis and a Principal Component Analysis. Based on the new material and the published specimens, we discuss the phylogeny of the genus and suggest that T. oehlerti and T.moravicus represent the ancestral forms of this small clad

New Ridged, Conical, Fissiculate Blastoid from the Permian of Timor

Abstract: Permian rocks from the Indonesian island ofTimor contain an abundant and diverse pelatozoanechinoderm fauna that was extensively monographed inthe first half of the twentieth century. Recent collectionshave produced specimens of Corrugatobastus savilli, n.gen. n. sp., the first genus of blastoid described from Timorin 70 years. Corrugatoblastus savilli is a ridged andfurrowed, conical, fissiculate blastoid with a highly unusualthecal morphology mimicking a small, solitary, rugosecoral. We have placed C. savilli in the family Codasterida,although it has several morphological features that areunique when compared to other genera in the family and to other blastoid genera regardless of familial assignment

Fourier Analysis of the Ostracode Margin

Abstract: Fourier analysis can be used as an objectivedescriptor of the ostracode margin. Results of the three examples suggest that the method explained may give information of interest to systematist. Use of Fourier analysis issuggested both for research on specimens and for study of illustrations from the literature

Stratigraphy and facies development of the marine Late Devonian near the Boulongour Reservoir, northwest Xinjiang China

Late Devonian to Early Carboniferous stratigraphic units within the ‘Zhulumute’ Formation, HonggulelengFormation (stratotype), ‘Hebukehe’ Formation and the Heishantou Formation near the BoulongourReservoir in northwestern Xinjiang are fossil-rich. The Hongguleleng and ‘Hebukehe’ formations are biostratigraphicallywell constrained by microfossils from the latest Frasnian linguiformis to mid-Famenniantrachytera conodont biozones. The Hongguleleng Formation (96.8 m) is characterized by bioclastic argillaceouslimestones and marls (the dominant facies) intercalated with green spiculitic calcareous shales. Ityields abundant and highly diverse faunas of bryozoans, brachiopods and crinoids with subordinatesolitary rugose corals, ostracods, trilobites, conodonts and other fish teeth. The succeeding ‘Hebukehe’Formation (95.7 m) consists of siltstones, mudstones, arenites and intervals of bioclastic limestone (e.g.‘Blastoid Hill’) and cherts with radiolarians. A diverse ichnofauna, phacopid trilobites, echinoderms(crinoids and blastoids) together with brachiopods, ostracods, bryozoans and rare cephalopods have beencollected from this interval. Analysis of geochemical data, microfacies and especially the distribution ofmarine organisms, which are not described in detail here, but used for facies analysis, indicate a deepeningof the depositional environment at the Boulongour Reservoir section. Results presented here concernmainly the sedimentological and stratigraphical context of the investigated section. Additionally, oneLate Devonian palaeo-oceanic and biotic event, the Upper Kellwasser Event is recognized near the sectionbase

Redescription of two Genera of blastoids from China

Abstract : In this paper we redescribe and reassign two genera of Chineseblastoids previously described by Mu (1955) and Chi (1943) based on our ownnew collections and those of other Chinese geologists. Mesoblastus tushanensisis reassigned to the Schizoblastidae from the Granatocrinidae based on the presence of ten spiracles and a separate anus and to the new genus Pinguiblastus. Previously Mississippian schizoblastids have been restricted toNorth America. Pinguiblastus provides a paleogeographic and evolutionarytransitional taxon between the North American schizoblastid genera and thevery abundant Permian faunas from Timor. Devonoblastus heitaiensis is reassigned to the new genus Sinoblastus, based on the presence of large exposed cryptodeltoids, a taxonomically significant character not found inDevonoblastus. This removes known occurrences of Devonoblastus from Asia