Development of horseradish peroxidase and tyrosinase-based organic-phase biosensors

Horseradish peroxidase-and tyrosinase-modified electrodes were constructed by entrapping the enzyme within an Eastman AQ 55D polymer matrix. The biosensors were used to detect their respective substrates (1 e organic peroxides and phenols) and inhibitors in polar orgamc solvents Horseradish peroxidase (HRP) inhibitors investigated mcluded thiourea, ethylenethiourea, mercaptoethanol, hydroxylamme and methyl isothiocyanate. Similarly, diethyldithiocarbamate was detected as a tyrosinase inhibitor Electrochemical methods such as cyclic voltammetry and steady-state amperometry, as well as spectroelectrochemistry, were used to characterise the analytical performance of these biosensors in organic solvents, namely acetomtnle, methanol, acetone, tetrahydrofuran, 2-propanol and 2-butanol. Operational parameters, such as the use o f a mediator, the effects of the chemical nature of the utilised mediator and its concentration, water content of the solvent and workmg potential were investigated and used to optimise the catalytic performance of the biosensors. The kinetic parameters for the sensors in the different organic media, such as the current as the substrate concentration approaches infinity (Imax), the apparent Michaelis-Menten constant (Km'), the apparent inhibition constant (K/) and Hill coefficients were determined. The differences in the values of these parameters were linked to the physico-chemical properties of the organic media, 1e solvent properties such as polarity, hydrophobicity, kinematic viscosity, dielectric constant, and solventenzyme mteractions. Finally, a glassy carbon electrode was modified with tyrosinase and a conductmg poly(l-vmylimidazole)-based osmium polymer. The ability o f this biosensor to function as a detector for high performance liquid chromatographic (HPLC) analysis of phenolic compounds such as p-ammophenol, phenol, p-cresol, catechol and pchlorophenol was characterised. The phenol sensor exhibited a 100 to 200-fold improvement in sensitivity and detection limit when compared to an ultraviolet-visible spectrophotometnc detector. The effects of operational parameters, such as the concentrations of the modifying compounds 1e the osmium polymer and the crosslinking compound, poly(ethylene glycol), the mobile phase composition and flow rate, the workmg potential and the biosensor’s short-term stability were investigated and optimised. The biosensor was used to measure phenol m an antiseptic cream, p-acetamidophenol (paracetamol) in a cold/flu relieving salt, and phenolic compounds in cigarette filter tips

State Surveillance, the Right to Privacy, and Why We May Need a New International Instrument

Especially since the beginning of the 19th century, surveillance has become an integral part of many states’ tool to maintain territorial integrity, inform foreign policies, and prevent foreign and domestic threats. Over the years, the means and modes of state surveillance have become more pervasive, more effective, and cheaper, thanks to incredible advancements in technology. By its very nature, state surveillance threatens an already endangered notion of privacy for which human beings have historically demonstrated an innate desire. So important is privacy, in fact, that for decades, it has been protected under international law as a fundamental right—a protection that is significant not only because privacy is such an integral right in itself, but also because without privacy, other civil liberties, such as the freedom of thought, belief, opinion and expression, cannot be fully or truly exercised. As technology continues to enhance states’ surveillance capabilities and as new and intrusive means capable of monitoring individuals and entire populations are developed, the idea of a global right to privacy—promoted by international law and its interpretations—crumbles. Not only that, as international law has remained relatively static in the face of changing states’ priorities, merging of our physical and digital worlds, and the consequent emergence of new privacy concerns, decades-old international law encounters serious problems. This thesis identifies and discusses the following key problems: first, as international law has failed to clearly regulate foreign surveillance, states have embraced the tendency to offer lesser privacy protections to foreigners, vis-à-vis their citizens/residents when conducting surveillance, thereby rendering questionable the idea of a universal right to privacy. Second, there are controversies regarding the application of international law to the extraterritorial surveillance activities of states. Third, although mass surveillance, particularly mass foreign surveillance, has become a standard part of some states’ national security and foreign relations practices, international law has failed to acknowledge mass (foreign) surveillance as a reality of state surveillance, let alone seek to regulate its deployment. Fourth, there are issues with the privacy guarantees under international law as there is little clarity on what the ‘right to privacy’ actually entails. Having identified and examined these problems, this thesis concludes that current international law rules on privacy are no longer adequate. The thesis then proposes the making of an international cyber surveillance and privacy instrument to resolve identified problems and set baseline standards for the conduct particularly of foreign and mass surveillance, in an ultimate bid to maintain some privacy in an increasingly connected and surveilled world. In other words, this thesis makes doctrinal arguments that highlight the flaws or lacunas in current international law on privacy and surveillance, and suggests the making of a new binding international instrument that would clarify current rules and address apparent lacunas

Fertility intention and contraceptive use among males in Nigeria

Thesis (M.A.)--University of the Witwatersrand, Faculty of Humanties, School of Social Sciences (Demography and Population Studies), 2013Background: Many African countries are still characterized by high fertility rates and low use of modern contraceptives despite numerous reproductive and health programs which aims to increase level of use in these countries. In recent times, there is an increasing body of literature on the role of men in family planning. These studies came about as a result of the inconsistencies observed with women’s inability to match fertility intention to their contraceptive behaviour despite the fact that most family planning programmes have concentrated on women. A potential explanation for this ambivalence is the great influence that male partners exert on women’s contraceptive use and fertility outcome in households. Could fertility intention of males therefore predict their modern contraceptive use in households? This study examined if and how fertility intention of males in Nigeria influences their modern contraceptive use. Methods: This is a cross-sectional study which used data from the Nigerian Demographic and Health Survey 2008. The population of interest in this study are sexually active males (had sex in the last one month before survey) of ages 15-59 interviewed during the survey. The dependent variable is current contraceptive use while the independent variables include demographic, socio-economic and reproductive characteristics of the males. The analysis of data was done at univariate, bivariate and multivariate levels to examine the association between male fertility intention and contraceptive use. Results: Results showed that only 9.0% of the 6,486 males in the study sample were using modern contraceptive methods, 13.1% want no more children and 33.4% want to delay having a/next child after two years while 33.4% want to have a/next child within 2 years. Fertility intention was found to be associated with use of modern contraceptive methods at both bivariate and multivariate levels. Result showed that men who do not want a/another child were significantly more likely (OR= 2.89) to use modern contraceptive method compared to men who wanted a/another child within two years. Men who wanted to space childbirth (want after two years) were also more likely to use modern contraceptive (OR= 1.61) when compared to men who wanted a child within two years. Conclusions: Men who were limiting or spacing child birth have higher propensity to use modern contraceptive method compared to men that wanted another child within two years. This suggests that fertility intention of men in Nigeria has an influence on their contraceptive behaviour and could be a good prediction for fertility outcomes in the country at large

Safety and efficacy of blood exchange transfusion for priapism complicating sickle cell disease.

BACKGROUND: Priapism is unwanted painful penile erection that affects about 36% of boys and men with sickle cell disease (SCD) most of whom have sickle cell anemia. Clinically, priapism could be stuttering, minor, or major. The first two types are mild, last \u3c 4 h, are usually treated at home, have good prognosis with normal sexual function. The major type of priapism lasts \u3e4 h, associated with severe pain, requires hospitalization; often does not respond to medical treatment and may require shunt surgery. Untreated major priapism and surgical intervention often cause impotence. In this study, we report our 15-year experience in treating adult patients with SCD and major priapism with blood exchange transfusion after being refractory to other medical therapies. METHODS: Adult male African Americans patients with SCD and major priapism were enrolled in this study and followed for 15 years. A Haemonitics V-50 machine was initially used for whole blood exchange and was later replaced with Cobe Spectra machine for RBC exchange. RESULTS: We used 239 blood exchanges requiring 1,136 RBC units. We maintained a post-exchange hemoglobin level of about 10 g/dL and hemoglobin S level \u3c 30%. None of the patients had any neurological complications such as headache, seizures, neurological deficits, or obtundation post-exchange. CONCLUSION: Together, the data indicate that blood exchange transfusion for the treatment of patients with SCD and major priapism is efficacious and safe

Social media in undergraduate medical education: A systematic review

Introduction There are over 3.81 billion worldwide active social media (SoMe) users. SoMe are ubiquitous in medical education, with roles across undergraduate programmes, including professionalism, blended learning, well being and mentoring. Previous systematic reviews took place before recent explosions in SoMe popularity and revealed a paucity of high-quality empirical studies assessing its effectiveness in medical education. This review aimed to synthesise evidence regarding SoMe interventions in undergraduate medical education, to identify features associated with positive and negative outcomes. Methods Authors searched 31 key terms through seven databases, in addition to references, citation and hand searching, between 16 June and 16 July 2020. Studies describing SoMe interventions and research on exposure to existing SoMe were included. Title, abstract and full paper screening were undertaken independently by two reviewers. Included papers were assessed for methodological quality using the Medical Education Research Study Quality Instrument (MERSQI) and/or the Standards for Reporting Qualitative Research (SRQR) instrument. Extracted data were synthesised using narrative synthesis. Results 112 studies from 26 countries met inclusion criteria. Methodological quality of included studies had not significantly improved since 2013. Engagement and satisfaction with SoMe platforms in medical education are described. Students felt SoMe flattened hierarchies and improved communication with educators. SoMe use was associated with improvement in objective knowledge assessment scores and self-reported clinical and professional performance, however evidence for long term knowledge retention was limited. SoMe use was occasionally linked to adverse impacts upon mental and physical health. Professionalism was heavily investigated and considered important, though generally negative correlations between SoMe use and medical professionalism may exist. Conclusions Social media is enjoyable for students who may improve short term knowledge retention and can aid communication between learners and educators. However, higher-quality study is required to identify longer-term impact upon knowledge and skills, provide clarification on professionalism standards and protect against harms

The Impact of Coporate Website on Dissemination of Research Information Among Stakeholders in Nigeria

This study accesses the influence of an official website as one that has been licensed by using an authority to signify itself or its houses online. Individuals, companies, governments, and different organizations can be such an authority. An internet portal is a web-based platform that gives employees, clients and suppliers with a single get right of entry to factor to information.8 A web portal can be used to supply the consumer with customized data such as employee training, protection manuals or a customer profile. A web portal can additionally be used to beautify the collaboration of information and improve the way employees, customers and suppliers interact with your commercial enterprise [7]. There are couple of reasons why an MSMEs will seem toward net portal development. This study was once made in two classes of lookup institutes: Health institutes and economic/social institutes. Comparison figures point out that there is no sizable difference in phrases of presence of a respectable website of Health Institutes and Economic/social institutes. Health Institutes have extra capability to diffuse their improvements to public than Economic/social institutes, using their website as a verbal exchange device of lookup findings dissemination. The comparisons of use of professional website, goal audiences were carried out as well as reliability check in percentages to allow conclusive results

Design of Automated Database System for Storage and Management of Reports on Mycotoxins Contaminated Agricultural Products in Sub-Saharan Africa

This paper discusses the idea and the design of an automated system for storage and management of mycotoxins reports for decision making Mycotoxins are poisonous chemical compounds produced by certain fungi Mycotoxins are fungal secondary metabolites that contaminate various feedstuffs and agricultural crops The contamination of food by mycotoxins can occur before production during storage processing transportation or marketing of the food products High temperature moisture content and water activity are among the factors that facilitate the production of mycotoxins in food The five major mycotoxins produced in food and feedstuffs are Aflatoxins ochratoxins fumonisins deoxynivalenol and zearalenon

Microperimetry reliability assessed from fixation performance

Purpose: Microperimetry provides an accurate assessment of central retinal sensitivity due to its fundus-tracking capability, but it has limited reliability indicators. One method currently employed, fixation loss, samples the optic nerve blind spot for positive responses; however, it is unclear if these responses arise from unintentional button presses or from tracking failure leading to stimuli misplacement. We investigated the relationship between blind spot scotoma positive responses (termed scotoma responses) and fixation. Methods: Part 1 of the study involved a custom grid of 181 points centered on the optic nerve that was constructed to map physiological blind spots in primary and simulated eccentric fixation positions. Scotoma responses and the 63% and 95% fixation bivariate contour ellipse areas (BCEA63 and BCEA95) were analyzed. In Part 2, fixation data from controls and patients with retinal diseases (234 eyes from 118 patients) were collected. Results: Part 1, a linear mixed model of 32 control participants, demonstrated significant (P < 0.001) correlation between scotoma responses and BCEA95. In Part 2, the upper 95% confidence intervals for BCEA95 were 3.7 deg2 for controls, 27.6 deg2 for choroideremia, 23.1 deg2 for typical rod–cone dystrophies, 21.4 deg2 for Stargardt disease, and 111.3 deg2 for age-related macular degeneration. Incorporating all pathology groups into an overall statistic resulted in an upper limit BCEA95 = 29.6 deg2. Conclusions: Microperimetry reliability is significantly correlated to fixation performance, and BCEA95 provides a surrogate marker for test accuracy. Examinations of healthy individuals and patients with retinal disease are deemed unreliable if BCEA95 > 4 deg2 and BCEA95 > 30 deg2, respectively. Translational Relevance: Microperimetry reliability should be assessed using fixation performance as summarized by BCEA95 rather than the level of fixation losses

Synthesis and characterization of a tetranuclear Cu(II) coordination polymer containing pyridine-2,6-dicarboxylic acid and 4-amidinopyridine co-ligand

This research demonstrates the preparation of a new coordination polymer, {[Cu4(H2pydc)2(H1apy)(H2O)2DMF].DMF}n, (H2pydc = pyridine-2,6-dicarboxylic acid, H1apy = 4-amidinopyridine) under solvothermal condition by the self-assembly of pyridine-2,6-dicarboxylic acid, 4-midinopyridene and copper(II) acetate. The compound was characterized by elemental analysis and infrared spectroscopic technique. The analysis indicated that the 4-amidinopyridine coordinated to the copper ions through the terminal nitrogen in a monodentate fashion while the pyridine-2,6-dicarboxylic acids coordinated through the carboxylate oxygens in monodentate mode. Both the elemental analysis and the infrared spectroscopic data agreed with the proposed stoichiometry. This result represent the first report of a tetranuclear Cu(II) coordination polymer having coordinated 4-amidinopyridine as the nitrogen donor moiety in its structure

Anthelmintička učinkovitost vodenog iscrpka biljke Euphorbia hirta u nigerijskih pasa.

The anthelmintic efficacy of the aqueous crude extract of Euphorbia hirta Linn was studied in 20 Nigerian dogs that were naturally infected with nematodes. They were randomly divided into 4 groups, A, B, C and D. Groups A and B each comprised 4 dogs while groups C and D comprised 6 dogs each. Group A animals were untreated, while those in group B were treated with proprietary anthelmintic (Mebendazole). Groups C and D animals were treated with aqueous crude extracts of E. hirta using intramuscular and oral routes, respectively. Two weeks after treatment, blood and faecal samples were collected to evaluate haematological values and faecal egg counts, respectively. The procedure was repeated two weeks later. Results of this study show that the aqueous crude extracts of E. hirta after its administration into local dogs produced a significant increase (P< 0.05) in PCV, RBC, Hb conc., TWBC and lymphocyte counts. The faecal egg counts also showed a remarkable and significant reduction in the levels of the identified helminths. The reduction in faecal egg counts was more pronounced with the extract administered through the oral route when compared with the intramuscular route. The effects of the plant extracts were broad spectrum in action. The phenol compound present in the plant extract could have caused reduction in worm load through this same mechanism that culminates in exhaustion and death of worms. Since the aqueous crude extract of E. hirta significantly reduced the faecal egg count of the helminths, it could serve as an anthelmintic agent.Anthelmintička učinkovitost vodenog iscrpka biljke Euphorbia hirta istražena je u 20 nigerijskih pasa prirodno invadiranih nematodima. Životinje su bile svrstane u skupine A, B, C i D. U skupini A i B bile su četiri životinje, dok su skupine C i D sadržavale šest životinja. Psi u skupini A nisu bili liječeni dok su oni u skupini B bili liječeni mebendazolom. Psi u skupini C bili su liječeni vodenim iscrpkom biljke i to intramuskularnom primjenom. Skupina D bila je liječena peroralnom primjenom vodenog iscrpka. Dva tjedna nakon liječenja svim psima izvađena je krv te sakupljene izmetine. Parazitološka pretraga izmetina bila je ponovljena nakon dva tjedna. Rezultati istraživanja pokazuju da vodeni iscrpak biljke Euphorbia hirta značajno (P<0,05) povećava broj krvnih stanica, eritrocita, leukocita, limfocita kao i koncentraciju hemoglobina. Promjene su dokazane i u nalazu parazitskih jaja. Smanjeni broj parazitskih jaja bio je izraženiji u skupini koja je iscrpak dobivala peroralno u odnosu na intramuskularnu primjenu. Pretpostavlja se da je upravo fenol kao komponenta iscrpka odgovoran za učinak na endoparazite. S obzirom da se njegovom primjenom značajno smanjio broj parazitskih jaja može ga se preporučiti i kao anthelmintik