107 research outputs found
The African State: An Illusory Vestige of Colonialism
In a 2006 Interview, prominent Nigerian author, and social commentator, Chimamanda Ngozi Adichie said; “…Nigeria was set up to fail. The only thing we Nigerians should take responsibility for is the extent of the failure….”1. Such a view about colonialism and the states it arbitrarily created is widely shared by many on the African continent, who have come to understand that the very creation and existence of the African state are largely to blame for the seemingly countless socio-economic and political issues faced on the continent.
1 Kimber, Charlie, Interview: Chimamanda Ngozi Adichie. The Socialist Review. (Online, October 2006)
Numerical modelling of the sound absorption spectra for bottleneck dominated porous metallic structures
Numerical simulations are used to test the ability of several common equivalent fluid models to predict the sound absorption behaviour in porous metals with “bottleneck” type structures. Of these models, Wilson's relaxation model was found to be an excellent and overall best fit for multiple sources of experimental acoustic absorption data. Simulations, incorporating Wilson's model, were used to highlight the relative importance of key geometrical features of bottleneck structures on the normal incidence sound absorption spectrum. Simulations revealed significant improvements in absorption behaviour would be achieved, over a “benchmark” structure from the literature, by maximising the porosity (0.8) and targeting a permeability in the range of 4.0 × 10 −10 m 2 . Such a modelling approach should provide a valuable tool in the optimisation of sound absorption performance and structural integrity, to meet application-specific requirements, for a genre of porous materials that offer a unique combination of acoustic absorption and load bearing capability
Biocompatible and Selective 18F-Fluorination Reagents for the Development of Biological Radiotracers for Positron Emission Tomography
Pathologies that require non-invasive, quantitative, and repeated investigation for treatment follow-up and for patient selection are on the rise due to longer life-expectancy and lifestyle changes. Early treatment and accurate diagnosis are required for curative intervention. Positron emission tomography (PET) offers a non-invasive and quantitative imaging modality for investigating biological processes, namely metabolism and receptor expression in tissues. To achieve the requirements of selectivity and sensitivity, various radiotracers need to be designed, synthesized and evaluated. Anything from small molecules to nanoparticles and biomacromolecules, are utilized as tracers, depending on the imaging target and the kinetics of the process under investigation.
Several tumors over-express on their surface receptors that can be targeted with biomolecules, such as peptides, extremely selectively. Peptides have specific amino acid sequences that interact with the binding site in the receptor, requiring careful design of the radiolabeling modifications in order not to disturb the interaction. Consequently, chemoselective radiolabeling methods are becoming more prevalent in the synthesis of biomolecular radiotracers. Given the high cost of radiopharmaceutical development, the availability of multipurpose, late-stage radiolabeling tools offering rapid radiotracer production from diverse target molecules would lower the development costs and provide wider selection of biological radiotracers for imaging studies.
The aim of this work was to develop fluorine-18-labeled tetrazines for preparing biological radiotracers for PET imaging. The novel tetrazines were studied for their metabolic stability and biological performance and used for in vitro radiolabeling of the target biomolecules. Heat sensitive serum albumin protein, and cyclic receptor targeting peptides, were radiolabeled with fast click reactions of the tetrazines providing chemoselective and mild radiofluorination. The first candidate tetrazine, fluorine-18 labeled silicon-fluoride acceptor tetrazine ([18F]SiFA-Tz) with a lipophilic prosthetic group, was found to be metabolically unstable and was further studied for its in vitro metabolism pathway in mouse liver microsomes with ultra-high performance liquid chromatography (UHPLC) high-resolution mass spectrometry (HRMS). Structural optimization was done and a metabolically stable and more hydrophilic fluorine-18 labeled alkylammoniomethyltrifluoroborate tetrazine ([18F]AmBF3-Tz) was developed, and evaluated with in vivo PET-computed tomography (PET/CT) imaging and ex vivo biodistribution studies where it demonstrated excellent stability. [18F]AmBF3-Tz is currently under further investigation for in vivo pretargeted PET imaging, due to the highly promising biological behavior as a standalone radiotracer. [18F]AmBF3-Tz was subsequently used as a radiofluorination reagent for somatostatin receptor-2 (SSTR2) targeting peptides. The lead peptide tracer was used for PET/CT imaging of preclinical pancreatic carcinoma model, providing clear visualization of the tumor xenografts. The findings presented in this study demonstrate the successful development of a novel radiolabeling tool to produce new biomolecular radiotracers for PET imaging.Sairaudet, jotka vaativat kajoamatonta, kvantitatiivista ja toistuvaa diagnostiikkaa hoidon seurantaan sekä potilasvalintaan, ovat kasvussa elinajanodotteen sekä elämäntapamuutosten johdosta. Varhainen diagnoosi ja oikea hoito ovat keskeisiä ennusteen parantamiseksi. Positroniemissiotomografia (PET) on kajoamaton ja kvantitatiivinen isotooppikuvantamismenetelmä, jolla voidaan tutkia biologisia prosesseja, kuten aineenvaihduntaa ja reseptorien ilmentymistä kudoksissa. Herkät ja selektiiviset kuvantamismenetelmät vaativat toimiakseen suuren valikoiman erilaisia radioleimattuja merkkiaineita. Merkkiaineen pohjana voidaan käyttää lähes mitä tahansa pienistä molekyyleistä nanopartikkeleihin sekä biomakromolekyyleihin, riippuen kuvannettavasta kohteesta ja tutkittavan prosessin kinetiikasta.
Useat kasvaimet yli-ilmentävät pinnallaan reseptoreita, joihin erilaiset biomolekyylit kuten tietyt peptidit sitoutuvat hyvin selektiivisesti. Tämä selektiivisyys syntyy peptidien aminohappotähteiden vuorovaikutuksesta reseptorin sitoutumispaikan aminohappotähteiden ja reseptoritaskun rakenteen kanssa. Viime aikoina biologisten radiomerkkiaineiden kehitys on painottunut kemoselektiivisiin radioleimausmenetelmiin, jotta vältytään tuhoamasta biomolekyylin luontaista toiminnallisuutta samalla valjastaen niiden poikkeuksellinen kohdentumiskyky kuvantamisen tarpeisiin. Monikäyttöisen, usealle eri kohdebiomolekyylille soveltuvan radioleimaustyökalun kehitys radiomerkkiainetuotantoon laskisi tuotantokustannuksia ja tarjoaisi useiden merkkiaineiden laajemman saatavuuden sairauksien diagnostiikkaan.
Tämän työn tarkoituksena oli suunnitella 18F-radioleimattuja tetratsiineja biologisten radiolääkeaineiden tuotantoon PET-kuvantamista varten. Uusia tetratsiineja tutkittiin niiden metabolisen stabiilisuuden sekä biologisen käyttäytymisen osalta ja niitä käytettiin biologisten kohdemolekyylien radioleimaamiseen in vitro. Lämpöherkkä seerumin albumiini -proteiini, sekä sykliset reseptorikohdentuvat peptidit radioleimattiin 18F-leimatuilla tetratsiineillä kemoselektiivisesti ja miedoissa olosuhteissa hyödyntäen käänteisesti elektronivajaata Diels-Alder reaktiota. Ensimmäinen kandidaatti, suhteellisesti rasvaliukoinen [18F]SiFA-Tz, osoittautui metabolisesti epästabiiliksi. Sen metaboliareittiä hiiren maksan mikrosomeissa in vitro tutkittiin edelleen käyttäen ultrakorkean erotuskyvyn nestekromatografia-korkean resoluution massaspektrometriaa (UHPLC-HRMS). Rakennetta optimoimalla kehitettiin metabolisesti erittäin stabiili ja vesiliukoisempi [18F]AmBF3-Tz, joka arvioitiin in vivo PET-TT-kuvantamisella (positroniemissiotomografia-tietokonetomografia) sekä ex vivo biodistribuutiokokeilla, joissa se osoittautui erittäin stabiiliksi ja farmakokinetiikaltaan lupaavaksi radiomerkkiaineeksi. [18F]AmBF3-Tz:a tutkitaan paraikaa esikohdennettuun PET-kuvantamiseen johtuen sen erittäin lupaavasta biologisesta käyttäytymisestä. Tässä työssä [18F]AmBF3-Tz:a käytettiin radiofluorausreagenssina somatostatiinireseptori 2:een (SSTR2) kohdentuville peptideille. Johtavaa peptidimerkkiaine-ehdokasta käytettiin PET-TT-kuvantamiseen prekliinisessä haimasyöpämallissa, jossa hiiriin istutetut kasvaimet oli mahdollista havaita selkeästi merkkiaineen avulla. Tässä työssä esitetyt löydökset osoittavat, että [18F]AmBF3-Tz on lupaava uusi radioleimaustyökalu biomolekyylipohjaisten radiomerkkiaineiden tuotantoon PET-kuvantamista varten
ALTERNATIVE DISPUTE RESOLUTION STRATEGIES FOR SUSTAINABLE DEVELOPMENT IN AFRICA: INSIGHTS FROM NIGERIA
Conflicts especially in Nigeria shall be explored in the course of this
paper. Also the concept of sustainable development, conflicts and contradiction in
the drive for sustainable development along with approaches to ensuring
sustainable development in Nigeria shall also be examined. We shall dwell further
on reported cases of conflicts in Nigeria and the incorporation of alternative
dispute resolution into the framework for sustainable development. And at the
Economic and social development in Africa has been hampered by a number of
interrelated issues. These include high cost of credit, low level of education and
the imbalance in a rapidly globalising world. There are also many cases of
conflicts, almost in the magnitude of organised terrorism. Media reportage has
not helped issues either. There is therefore the need to seek alternatives in
managing these conflicts. It is this desire that provides motivation for this paper.
The conceptual framework of sustainable development as well as the provisions of
Alternative Dispute Resolution in dealing end of the paper it shall be proffered
that alternative dispute resolution is a better remedy for conflict resolution. We
are optimistic that the results will provide viable alternatives to resolving conflicts
and thus ensure sustainable development in the continent
CATANOVA Analysis of Knowledge and Control Practices of Hepatitis B Virus Infection amongst Tertiary University Students
Frequency data, having no underlying metric, are frequently encountered in real-life situations. The analysis of such data is usually difficult as nominal data are inherently less informative than quantitative data and decisions are taken erroneously using such results.
The objective of the research was to study the significant effect of gender, faculties and interaction using categorical data in a two-way cross classification.
Materials and Methods. The study applied a cross sectional study with a total sample size of 434. Multistage sampling was adopted. Categorical analysis of variance (CATANOVA) technique was used for analysis. This is suitable as it uses a two-way ANOVA with quantal responses as equivalent of a three-way contingency table in which one of the classifications is treated as responses to the other two. The study considered frequency data involving response scores of students using a scale of good, fair and poor.
Results. Numerical results revealed poor level of student’s knowledge and control practices of hepatitis B virus infection. And it is significantly (p>0.05) the same in the study Universities. Moreover, gender and faculties, as well as interaction have no significant (p>0.05) effect on student’s knowledge and control practices of hepatitis B virus infection
Airflow measurement across negatively infiltration processed porous aluminum structures
Detailed structural characterization and experimental measurement of airflow across open-celled aluminum foam structures with near-spherical cells varying in pore sizes and interstices are presented herein. The aluminum foam structures were produced by infiltrating liquid aluminum into convergent gaps created by packed beds of near-spherical hydrosoft salt beds varying in particle sizes, packing densities, and infiltration pressures. A quantitative assessment of the unit pressure drops developed across these structures show that viscous and inertial terms of these structures were observed to greatly depend on the shape and structural macroscopic parameters of the porous medium. © 2019 American Institute of Chemical Engineers AIChE J, 2019. © 2019 American Institute of Chemical Engineer
Marketing relacional y fidelización de los clientes en Bibi Pet Shop & Spa - Chiclayo 2022
La presente investigación tuvo como objetivo determinar la relación existente entre
el marketing relacional y la fidelización de los clientes en Bibi Pet Shop & Spa. Fue
de enfoque cuantitativo, de tipo aplicada, con un nivel descriptivo correlacional,
diseño no experimental y de corte transversal. Como población se tomó en cuenta
a 70 de los clientes fidelizados, asimismo, por contar con el número reducido de
población de decidió emplear una muestra poblacional. Con respecto a la técnica
de recolección de datos, se empleó la encuesta mediante formularios virtuales,
dicho formulario contaba con 20 ítems. El instrumento fue validado por tres expertos
en el tema. Además, la confiabilidad del instrumento por parte de la variable de
marketing relacional determinó el valor de 0.875 y para la variable de fidelización
de clientes el valor de 0.798. Finalmente se obtuvo como resultado que las variables
de estudio tienen una relación significativa alta, con un coeficiente de correlación
entre el marketing relacional y la fidelización de clientes es 0.725 con una
significancia <0.000
Mapping Invasive Giant Goldenrod (Solidago gigantea) with Multispectral Images Acquired by Unmanned Aerial Vehicle
Invasive alien species are one of the main threats to worldwide biodiversity loss. Unmanned aerial vehicles with multispectral sensors offer a cost-effective alternative to monitor invasive plant species at a centimetre scale. Giant Goldenrod (Solidago gigantea) is one of the most problematic invasive alien plant species in Switzerland and controlling this species – especially in nature protection areas – is a priority. In this study, a methodology is developed to detect the Giant Goldenrod coverage via unmanned aerial vehicle (UAV) equipped with multispectral sensors. Very high resolution maps (6.5 cm) are produced and high accuracy is achieved for the classification of the Giant Goldenrod coverage with a kappa coefficient of 0.902 and an overall accuracy of 92.12%. These results indicate that UAV equipped with multispectral sensors is a valuable tool in monitoring and combatting invasive alien species
An Empirical Evaluation of Agribusiness Firms Perceptions of the Impact of E-Marketing Strategy on Distribution Channel.
Many farms have begun operating websites in order to promote
their businesses. The internet represents a significant change in the
competitive landscape. individuals use internet for different reasons including social iutemctio1z, obtaining information, and
purchasing goods and services. Modem distribution is been shifted
from paper-based, people-intensive marketing systc111s towards
electronic-based procedures that rely on internet communications
and web-enhanced software tools. The objective of this paper is to
examine the evalution of Agributsiness firm's perceptions of the
impact of e-marketing strategy on distribution channel. A
questionnaire was prepared based On the review of current
literature and distributed to a number of agribusiness firms
employees in Ota metropolis of Ogun state. One hundred and
twenty completed surveys were received from the firms ·who have
adopted e-marketing strategy. Based on the 120 completed survey
questionnaires, simple stylistics were carried out and it was
discovered that some factors that influence the implement ation of e-marketing
in study area include among others distance, time, place,
and competition. Based on the findings, conclusion and
recommendations were given
Anthelmintička učinkovitost nepročišćenog metanolskog iscrpka biljke Xylopia aethiopica protiv oblića Nippostrongylus brasiliensis u štakora
Xylopia aethiopica A. Rich (X. aethiopica; Annonaceae) is used commonly in Nigeria by traditional herbalists and pastoralists to control gastrointestinal helminth parasites. The anthelmintic effect of the crude methanol extract was evaluated in rats experimentally infected with the rat hookworm Nippostrongylus brasiliensis. Thirtyfive rats were each infected subcutaneously with 200 third stage infective larvae of the parasite and randomly
grouped into seven groups. Five days after infection, rats in siof the groups were treated with the extract, the dose varying per group. Rats in the seventh (control) group were each given propylene glycol. Anthelmintic activity was assessed by comparing the number of worms recovered from treated rats to those from non-treated infected control rats. The extract at the dose of 0.8 g/kg, 1.0 g/kg, 1.2 g/kg, 1.4 g/kg, 1.7 g/kg and 2.0 g/kg produced deparasitization rates of 21%, 47%, 51%, 50%, 63% and 76% and were signifi cant (P>0.05) when compared to untreated control rats.Travari i stočari u Nigeriji tradicionalno koriste biljku Xylopia aethiopica protiv želučano crijevnih helminata. Anthelmintički učinak nepročišćenog metanolskog iscrpka istražen je na pokusno invadiranim štakorima oblićem Nippostrongylus brasiliensis. Ukupno 35 štakora podijeljeno je u sedam skupina. Svi štakori supkutano su invadirani s 200 invazijskih ličinki trećeg stupnja. Pet dana nakon invazije, štakorima iz svih šest skupina apliciran je iscrpak u različitim dozama. Štakorima sedme skupine primijenjen je propilen glikol. Učinkovitost je određena uspoređivanjem broja parazita u liječenih i neliječenih štakora. Značajna (P<0,05) anthelmintička učinkovitost dokazana je za sve primijenjene doze. Tako je rezultat primjene iscrpka u dozi od 0,8 g/kg bio smanjeni broj parazita za 21%. Veće doze (1,0 g/kg i 1,2 g/kg) smanjile su broj parazita za 47% i 51%. Za najviše doze (1,7 g/kg i 2,0 g/kg) potvrđena je i najviša učinkovitost od 63% i 76%
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