Manufacturing of agarose-based chromatographic adsorbents with controlled pore and particle size

Chromatography remains the most commonly employed method for achieving high resolution separation of large-sized biomolecules, such as plasmid DNA, typically around 150-250 nm in diameter. Currently, fractionation of such entities is performed using stationary phases designed for protein purification, typically employing pore sizes of about 40 nm. This results into a severe underexploitation of the porous structure of the adsorbent as adsorption of plasmid DNA occurs almost exclusively on the outer surface of the adsorbent. In this study, the effect of two processing parameters, the ionic strength of agarose solution and quenching temperature, on the structure of the resulting particles was investigated. Three characterization methods, Atomic Force and cryo-Scanning Electron microscopy, as well as mechanical testing of single particles where used to quantify the effect of these parameters on the pore size/size distribution and mechanical properties of the adsorbent. In the presence of salt, it was found that agarose fibres tend to aggregate, leading to a gel with large pore size and wide pore size distribution. In fact, for the narrow range of ionic strength used (0-0.1m), a five-fold increase in pore size of the gel was observed. The same type of enlarged agarose structures was observed when slow cooling was applied during the gelation of agarose. The increase in pore size of the gel was also accompanied by an increase in the compression strength and the elastic modulus of the particles, i.e. particles with 200 nm pore size were found to have higher compression strength (1.5-fold difference) than those with 40 nm pore size

Developing and Characterizing a Novel TEMPO CNF Hydrogel Adjuvant and Delivery System for Aquatic Vaccines

Aquaculture is a large part of the food production sector which is greatly expanding. One of the largest losses in aquaculture is due to pathogens. Current solutions for protecting farmed finfish from pathogens can be very expensive with variable efficiency. Current disease prevention strategies include vaccination. Types of vaccines include immersion vaccines, feed vaccines, and injectable vaccines. The most popular solution is oil-based injectable vaccines due to its protection. However, the oil-based adjuvant used in most of these formulations causes adverse reactions in the fish including reduced growth. These vaccines require multiple administrations throughout the fish’s lifetime causing unwanted handling stress and additional labor costs. Preliminary trials show that cellulose nanomaterials cause minimal adverse reactions when injected into salmon and does not significantly affect their growth. The goal of this research was to create an adjuvant from cellulose nanomaterials which would increase bacterin efficacy while avoiding harmful side effects. A prolonged release formulation was also desirable, obviating the need for multiple vaccinations. Additionally, hydrogels have been used for a wide variety of applications including drug delivery, making them an attractive aquatic vaccine adjuvant. Cellulose nanomaterials were decided as the polymer to make up the hydrogel matrix due to their biocompatibility, sustainability, high tunability, high abundance, low cost. The development of the hydrogel formulation, modifying the hydrogel for easier delivery into the salmon, measuring the diffusive properties of the hydrogel, and in vivo testing of the hydrogel for analysis of delivery methods and reactions to the formulation are described in this research

Crossflow microfiltration modelling and mechanical means to prevent membrane fouling

The definition, history and applications of Microfiltration (MP) are briefly reviewed in Chapter 1. The physical mechanisms and mathematical models of the filtration process including concentration polarization (CP), gel polarization (GP) and pore blocking are given in Chapter 2. Crossflow microfiltration membrane fouling and the deposition of solids onto the filter surface have been investigated using a process fluid (seawater), latex and a ground mineral. The performance of various membrane materials has also been studied, including: acrylonitrile, polypropylene, PTFE, ceramic and stainless steel. The seawater filtration work showed in Chapter 3 that good filtrate flux rates can be maintained if material fouling or depositing on the membrane can be prevented from entering the membrane structure. A surface deposit may be removed by mechanical means such as backflushing with permeate or compressed air. This aspect of the work indicated that a more comprehensive study of fouling was required. Existing crossflow filtration membrane models did not adequately represent even the simplest filtration when penetration of the membrane structure applied. Such conditions occurred during latex filtration in Chapter 4. Latex of varying sizes and density were manufactured and filtrations using acrylonitrile membranes were performed. Considerable deposition of latex inside the membrane pores occurred despite the nominal rating of the membrane being less than the latex particle diameter. Thus the membranes relied on a depth filtration mechanism rather than a surface straining mechanism for filtration effectiveness. A standard filtration blocking model was modified for use in crossflow microfiltration, coupled with a mass balance on the amount of material filtered. This mathematical model was then used to predict and correlate the rate of filtration flux decay with respect to filtration time during crossflow filtration. The model provided acceptable accuracy and is an improvement on existing empirical models for the flux decay period. Under the circumstances of membrane penetration it is advisable to minimise the amount of material entering the membrane structure. Mechanical means to achieve this were investigated and a novel anti-fouling method using a centrifugal field force and enhanced shear stress at the membrane surface was developed. The filtration of limestone slurries with three different tubular filters are presented in Chapter 5, in which one filter was conventional, the other two novel ones were specially designed for the separation of particles with a density different from that of the liquid, one used a helical channel around the filter, and the other had tangential inlet and outlet endcaps. The centrifugal force produced by the spinning flow around these two filters retarded the approach of particles towards the membrane surface so that the particle deposition was reduced. The results showed such a system was energy efficient, saving 20 % of the energy required to effect a separation of mineral material compared with using the membrane in a more conventional way

Progression Magazine, 2017 Winter

Magazine of the College of Science at Coastal Carolina University.https://digitalcommons.coastal.edu/progression/1009/thumbnail.jp

Studies on freshwater phytoplankton, with special reference to the Desmidiaceae

The papers submitted herewith relate to personal researches on various aspects of the biology of phytoplankton principally in Scottish freshwater lochs but also of the river plankton in the White and Blue Niles in the Sudan. The latter studies were conducted as part of a programme of work on the fundamental hydrobiology of the Nile initiated by Dr. J. Rzoska and the author, who together inaugurated the Nile Hydrobiological Research Unit. An introduction to this work is the systematic account of the algal plankton of both rivers (1) and is based on collections made between 1949 and 1952 from the Blue Nile at Khartoum and from many places between Khartoum and the Sudd region on the White Nile. Some of the effects, on the river's plankton and hydro -chemistry, of impounding water above the Gebel Aulyia Dam on the White Nile, south of Khartoum, were studied by taking a succession of samples from the Dam upstream for 325 Km (2). It was found that the plankton showed a numerical increase of more than 100 -fold, the increase being; associated with the change from river -to lake -like conditions as the Dam was approached. The seasonal development of the plankton in the White and Blue Nile has also been investigated (3). This study was based on regular samples collected over a period of three years, from 1951 -53, and indicates that although regular annual fluctuations in plankton density occur in both rivers, their peaks do not coincide but show a marked dependance on the specific hydrological regimes of the two rivers, which are briefly summarised. Related to these studies on Nile algae are some observations on the ecology of the terrestrial alga, Fritschiella tuberosa which makes a seasonal appearance on drying mud on the banks of the Blue Nile (4.). Some details of the exacting environmental conditions under which this alga grows are presented. A comprehensive survey and bibliography of the literature relating to the freshwater algae of Africa has also been compiled (5).The papers on the phytoplankton of Scottish freshwater lochs have been assigned to three categories. These relate to studies: -I. On water replacement in relation toe plankton productivity (6). Here it has been shown that water inflow and outflow in small lakes may be a factor of over -riding importance in determining the abundance of plankton. This study is related to the observations made on the White Nile plankton at the Jebel Aulyia Dam (2).II. On the effects on the phytoplankton of addin mineral fertilizers to hill lochs (7 & 8), These studies which are contributions towards investigations of the factors affecting the biological productivity of Scottish freshwaters, show that quite small additions of phosphate produce quite profound and prolonged effects on the phytoplankton of the treated lochs. Also bearing on this work are observations made on the aquatic fauna as an ecological factor in studies of the occurrence of freshwater algae (9). During the course of all these investigations the phytoplankton of many lochs were examined and observations made on this somewhat neglected aspect of Scottish vegetation. These have been published in a series of short papers (10 -14).III. On the desmid- plankton which is especially prominent in many Scottish lochs (15=22). This aspect of phytoplankton research was begun in an attempt to use plankton algae as indications of the trophic status of lakes (15 & 16). It was found, however, that the taxonomy of the most commonly occurring genus, Staurastrum, was so confused that before any real progress could be achieved a detailed reinvestigation would have to be made of many of the supposedly well established, commonly occurring species. Most prominent amongst these were S. paradoxum and S. gracile, species which, according to the literature are amongst the most widespread of plankton organisms not only in the British Isles and Europe, but throughout the world. An attempt has therefore been made to rationalize the taxonomy of these two supposedly cosmopolitan species (17 - 21). Studies have also been made on other desmids from the British freshwater plankton again with special reference to the genus Staurastrum (22 - 25).PUBLISHED PAPERS:- (01) A systematic account of the phytoplankton of the Blue and White Nile. Ann. Mag. Nat. Hist. Ser. 12, vol. 7, 195+, 648 -656. || (02) The influence of the Gebel Aulyia Dam on the development of Nile plankton. J. Animal Ecol., 23, 1954, 101 -111+. (with J. Rzoska). || (03) Seasonal plankton development in the White and Blue Nile near Khartoum. Verh. int. Ver. Limnol., 12, 1955, 327 -331+. (with J. Rzoska, and G.A. Prows. || (04) On the ecology of the terrestrial alga, Fritschiella tuberosa, in the Sudan. New Phytol., 56, 1956, 130 -132. || (05) A bibliography of African freshwater algae. Rev. Algol. 1957, 207 -238. (with Ross, Kufferath & Sims). || (06) Some observations on the effects of water inflow and outflow on the plankton of small lakes. J. Animal Ecol., 22, 1956, 22 -35. (with W.B. Woodward). || (07) Fertilization experiments on Scottish freshwater lochs. I. Loch Kinardochy. Sci. Invest. Freshwat. Fish. Scot. 17, 1957, 30 pp. (with A.V. Holden). || (08) Changes in the phytoplankton of some Scottish hill lochs resulting from their artificial enrichment. Verh. internat. Ver. Limnol. XIII, 1958, 298 -305. || (09) The aquatic fauna as an ecological factor in studies of the occurrence of freshwater algae. Rev. algol., (N.W.) 1, 1955, 11+1 -11+50 || (10) Notes on some uncommon algae from lochs in the Tu.mmel -Garry catchment area. Trans. bot. Soc. Edinb., 36 (3), 1954 -, 207 -211+. || (11) Notes on some uncommon algae from lochs in Kinross, Perthshire and Caithness. Trans. bot. Soc. Edinb., 1955, 309 -16. || (12) Notes on freshwater algae, mainly from lochs in Perthshire and Sutherland, Trans. bot. Soc. Edinb., IL 1957, 114 -122. || (13) Notes on algae from the plankton of some Scottish freshwater lochs. Trans. bot. Soc. Edinb., 37 (3), 1958, 174 -181. || (14) On some forms of Micrasterias new to or rare in Britain. Naturalist, Lond., April -June, 1957, 37 -39. || (15) The status of desmids in the phytoplankton and the determination of phytoplankton quotients. J. Ecol., 4-7, 1959, 429 -445. || (16) The phytoplankton of some Irish loughs and an assessment of their trophic status. Proc. Roy. Irish Acad., 60 B. (4), 1959, 167 -191. (with F.E. Round). || (17) Notes on desmids of the genus Staurastrum III. S. paradoxum Meyen in the Jenner Herbarium of the British Museum. Naturalist Lond., July -Sept. 1959, 81 -83. || (18) The published figures of the desmid Staurastrum paradoxum. Rev. Algol. 4-, 1959, 239 -255. || (19) Staurastrum paradoxum Meyen and S. gracile Ralfs in the British freshwater plankton, and a revision of the S. anatinum - group of radiate desmids. Trans. Roy. Soc. Edinb. LXIII No. 26, 1959, 589 -628. || (20) De Brebisson's determinations of Staurastrum paradoxum Meyen and S. gracile,Ralfs. Nova Hedwigia, 1(2), 1959, 163 -166. || (21) The varieties of Staurastrum paradoxum Meyen - nomen dubium. Nova Hedwigia, 1(4.), 1960, 431 -422. || (22) Notes on desmids of the genus Staurastrum I. S. pseudopelagicum, S. subcruciatum, S. avicula and S. denticulatum. Naturalist, Lond., July -Sept. 1957, 97-100. || (23) Notes on desmids of the genus Staurastrum. II. S. leptodermum, S. longispinum, S. brasiliense, S. setigerum, S. clevei and S. tohopekaligense var. trifurcata. Naturalist, Lond. July - Sept. 1958, 91 -95e || (24) Staurastrum pendulum var. pinguiforme Croasdale. S. micron, West, f. major f. nov., fac. quadrata and S. micron var. perpendiculatum (Cronblad) nov. comb., desmids new to the British freshwater plankton. Nova Hedwigia, 1(2), 157 -162, || (25) Desmids from the plankton of some Irish loughs. Froc. Royl. Irish Acad. B (6), 1958, 71 -91

Progression magazine Winter 2017

Progression Magazine is published by the Gupta College of Science at Coastal Carolina University and highlights the marine-related work of the students, faculty, and staff, events, and educational and research information of students and faculty