82 research outputs found
Cataract surgery and non-attendance: RCT to determine the effect of a SMS reminder system and financial impact in a developing country
AIMS: Missed cataract surgical appointments are an important cause of inefficiency, with delays in appropriate treatment, loss of continuity of care, and wasted resources. This study was conducted to determine if an SMS reminder system will reduce the failure to attend (FTA) rate by our patients who are booked for cataract surgery. METHODS: A randomised controlled trial was conducted at Groote Schuur Hospital between June 2015 and June 2016. Eligible patients were randomised into one of two study groups: either the "NO reminder control group "or the "SMS reminder intervention group". Patients in the SMS reminder group were entered into a secure web platform from which the automated SMS reminder system dispatched an SMS reminder one month, four days and one day pre-operatively between 10am and 12am. The message contained the following: "Dear "Mr/Mrs name", this is to confirm your cataract surgery at Groote Schuur Hospital, booked for "date". Please phone 021 404 3541 if any queries." RESULTS: 234 patients were enrolled into this study, and 15 patients were excluded. Of the remaining 219 patients, 111 were randomised into the NO reminder group (control) and 108 into the SMS reminder group (intervention). SMS reminders reduced the FTA rate by 52.6% from 11.7% to 5.6% (p=0.11). Transport problems were identified as the most common reason for non-attendance. CONCLUSION: An SMS reminder system aids in the reduction of non-attendance for booked cataract surgery. With an estimated cost of only 54 cents for three SMS reminders, this affordable intervention results in an improved efficiency of clinical service delivery
Characterization and evaluation of glucose oxidase activity in recombinant Saccharomyces cerevisiae strains
Thesis (PhD)--Stellenbosch University, 2010.ENGLISH ABSTRACT: Popular wine styles prepared from fully-ripened, more mature grapes are characterized
by intense fruitiness and varietal flavors. However, lengthy maturation of
grapes in the vineyard does not only translate into higher flavor intensity but also
into higher sugar levels, which, in turn, leads to wines with higher concentrations of
alcohol. Excessive alcohol levels can compromise wine flavor and render wine unbalanced.
This, along with health issues and anti-social behavior linked to high-risk
alcohol consumption patterns, stricter legislation and increased tax rates associated
with high-alcohol wines, have increased demand for wines with reduced alcohol
concentrations, without loss of the intense fruity aromas. Although low-alcohol
wines can be made using physical post-fermentation processes, such approaches are
often expensive and can impact adversely on wine flavor. As an alternative strategy,
yeast strains are being developed by several research groups to convert some of the
grape sugars into metabolites other than ethanol.
Based on promising results from previous preliminary work, this study focused
on the development of an industrial Saccharomyces cerevisiae wine strain producing
glucose oxidase (GOX; b-D-glucose:oxygen oxidoreductase, EC 1.1.3.4).
GOX oxidizes b-D-glucose to D-glucono-d-lactone and gluconic acid (GA) extracellularly,
thus preventing its entry into glycolysis, thereby diverting a portion of the sugar carbon away from ethanol. The GOX-encoding gene from the foodgrade
fungus, Aspergillus niger was used to construct three cassettes (GOX1, GOX2
and GOX2LOX). In these gene cassettes, the A. niger GOX gene was placed under
the regulation of the S. cerevisiae phosphoglycerate-kinase-1 gene promoter
(PGK1P) and terminator (PGK1T ). To facilitate secretion, in GOX1 the yeast mating
pheromone-factor a secretion signal (MFa1S) was fused to the GOX gene, and
in GOX2 the native A. niger secretion signal of GOX was used. These gene cassettes
were each integrated into the genome of two laboratory yeast strains (BY4742 and
S1278b) and one industrial wine yeast strain (VIN13). An additional integration
cassette, designated GOX2LOX, was constructed to knock out the IME1 gene in S.
cerevisiae. In GOX2LOX, GOX2 was fused to a loxP cassette. VIN13-D1 was obtained
by integrating a single copy of GOX2LOX into the IME1 locus. To generate
an asporogenic, GOX-producing wine yeast, VIN13-D2 was created by sporulation,
micromanipulation and re-diploidisation of VIN13-D1. Comparative analysis indicated
that (i) GOX2 resulted in higher levels of extracellular glucose oxidase activity
than GOX1; and that (ii) the levels of secreted glucose oxidase activity in the wine
yeast transformants were sufficiently high to conduct follow-up small-scale wine
fermentation trials.
The wine yeast transformant, VIN13-D1 was evaluated under red and white experimental
winemaking conditions. Results from this work indicated that glucose
oxidase was produced and secreted by VIN13-D1 that dominated the fermentation
to the end, but also that the enzyme was not highly active under the evaluated winemaking
conditions. Consequently, no significant decrease in ethanol concentrations
was observed in the wine made from VIN13-D1 when compared to that from
VIN13. Wine samples were analyzed by Fourier transform-middle infrared spectrometry
(FT-MIR) to determine the chemical composition and Gas chromatography
with a flame ionization detector (GC-FID) to evaluate the concentrations of
aroma compounds. The levels of gluconic acid were determined by enzymatic assays.
Multivariate data analysis (PCA and PLS1-discrim) was applied to highlight
significant differences between the wines made by VIN13 (wild-type) and VIN13-
D1. Chemometric projections of the score plots for all results allowed insight into
all significant variation up to three principal components (PCA) or PLS components,
which showed very clearly that GA is a key factor in evaluating the effect of
GOX in VIN13-D1 fermentation with regard to VIN13 fermentations. The VIN13-
D1 effect manifestations were best shown on PLS1-discrim score plots that revealed that, of the restricted variable subsets the FT-MIR-compounds and GC-compounds
yielded better results, with the GC-compounds displaying greater discriminability
between cultivars and VIN13 / VIN13-D1. It can be concluded from these results
that the greatest influence of VIN13-D1 produced wines could be observed in the
aroma components, but, because there were also discriminability effects discernable
in the FT-MIR-compounds, thus the flavor components were also affected.
The activity of GOX in grape juice was further investigated in controlled small
scale fermentations performed in a bio-reactor. It was confirmed that GOX is active
under aerobic conditions, inactive under anaerobic conditions, and can be activated
instantly when an anaerobic culture is switched to aerobic conditions (simulated
micro-oxygenation). These fermentations showed that glucose oxidase is active in
grape juice, and that oxygen play a key-role in the enzyme’s activation. Finally, it
was shown with the help of a simplified model, that under ideal conditions, GOX
secreted from VIN13-D1, can be employed to reduce the ethanol by a predefined
concentration for the production of low alcohol wines.
This work gives more insight into how to employ a GOX-producing wine yeast
during winemaking and strongly suggests the use of micro-oxygenation to activate
the enzyme in order to reduce available glucose, thereby diverting a portion of the
sugar carbon away from ethanol production.AFRIKAANSE OPSOMMING: Gewilde wynstyle word dikwels gemaak van volryp, goed ontwikkelde druiwe,
gekarakteriseer deur intense aromas en smaakkomponente wat direk met spesifike
kultivars geassosieer word. ’n Nadelige gevolg om druiwe te lank aan die wingerdstok
te laat bly hang sodat meer intense geurkomponente kan ontwikkel, is die
toename in suikerinhoud. Hierdie addisionele suiker lei tot wyne met hoër alkoholvlakke.
Te hoë alkoholvlakke kan wyn ongebalanseerd laat voorkom en die
smaak nadelig beïnvloed. Dit, tesame met gesondheidsredes en anti-sosiale gedrag
wat gekoppel kan word aan die inname van te veel alkohol, strenger wetgewing
aangaande dronkbestuur en die toename in belasting op wyne met ’n hoër alkoholinhoud,
het aanleiding gegee tot ’n aanvraag vir wyn met ’n verlaagte alkoholinhoud,
sonder dat aroma- en geurkomponente ingeboet word. Alhoewel daar sekere
fisiese/gemeganiseerde prosesse beskikbaar is om die alkohol in wyn te verwyder of
te verminder, is ’n nadeel dat hierdie prosesse baie duur en arbeidsintensief is, en dat
dit deur sommige wynpuriste as te ingrypend in die ‘natuurlike’ proses van wynmaak
beskou word. Sommige van hierdie alkoholverwyderingsprosesse kan ook die wyn se geur- en aromakomponente nadelig beïnvloed. As alternatief tot hierdie
fisies-chemiese prosesse word wyngiste reg oor die wêreld deur verskillende
navorsingsgroepe ontwikkel sodat van die druifsuikers nie na alkohol omgeskakel
word nie, maar eerder ander metaboliete.
Belowende navorsingsresultate in ’n voorafgaande studie het aanleiding gegee
tot hierdie navorsingsprojek. In hierdie studie word daar klem gelê op die ontwikkeling,
deur middel van genetiese manipulering, van ’n industriële wynras van
Saccharomyces cerevisiae sodat dit in staat sal wees om glukose-oksidase (GOX;
b-D-glukose:suurstof oksidoreduktase, EC 1.1.3.4) te produseer. GOX kan reeds
b-D-glukose in die medium oksideer na glukoonsuur (GA), wat sodoende verhoed
dat dit verder gemetaboliseer word via glukolise, en dit het tot gevolg dat
’n gedeelte van die beskikbare suiker nie omgeskakel word na alkohol nie. Die
strukturele glukose-oksidase-geen (GOX) van die voedsel-gegradiëerde fungus, Aspergillus
niger is gebruik tydens die konstruksie van drie kassette (GOX1, GOX2 en
GOX2LOX). Binne hiedie geenkassette is A. niger se GOX-geen se transkripsieinisiëring
en -terminering onafhanklik deur die fosfogliseraat-kinase-1-promotor
(PGK1P) en termineerder (PGK1T ) bewerkstellig. Om uitskeiding van GOX uit die
gis te bewerkstellig, is daar van die a-spesifieke gisferomoon-a-faktor (MFa1S)
in GOX1 gebruik gemaak, en in GOX2, van A. niger se eie natuurlike sekresiesein.
Hierdie geenkassette is binne-in die genoom van twee labaratoriumgisrasse
van S. cerevisiae (BY4742 en S1278b) asook een industriële wyngisras (VIN13)
geintegreer. ’n Addisionele integreringskasset (die sogenaamde GOX2LOX-kasset)
is gemaak om die IME1-geen van S. cerevisiae te elimineer. Binne die GOX2LOXkasset
is GOX2 aan ’n loxP-kasset gekoppel. Die nuwe wyngis VIN13-D1 is verkry
deur ’n genomiese integrasie van GOX2LOX binne-in die IME1-lokus. Om die niesporulerende
GOX-produserende wyngis VIN13-D2 te verkry, is VIN13-D1 gesporuleer,
onderwerp aan mikromanipulasie en toegelaat om te herdiploidiseer. Ontledings
het aangedui dat (i) GOX2 aanleiding gegee het tot hoër vlakke van ekstrasellulêre
glukose-oksidase aktiwiteit in vergelyking met GOX1; en (ii) dat die
vlakke van uitgeskeide biologies-aktiewe glukose-oksidase vir die wyngisrasse aansienlik
hoër was. Dit het verdere kleinskaalse wynfermentasies geregverdig.
Die getransformeerde wyngis VIN13-D1 is op eksperimentele skaal in die maak
van rooi- en witwyn geëvalueer. Ontledings van hierdie eksperimentele wyne het
daarop gedui dat glukose-oksidase deur die VIN13-D1-gisselle geproduseer en suksesvol
uitgeskei tydens die wynmaakproses is, en dat VIN13-D1 die fermentasie gedomineer het en die alkoholiese gisting voltooi het. Resultate het egter ook aangedui
dat die geproduseerde glukose-oksidase nie baie aktief was onder die wynmaaktoestande
wat in hierdie eksperimentele wynmaakproses gegeld het nie, en gevolglik
was daar nie ’n drastiese verlaging in die alkoholvlakke sigbaar toe VIN13-D1
se wyne met VIN13 se wyne vergelyk is nie. Wynmonsters is deur middel van
Fourier-transformasie-mid-infrarooispektroskopie (FT-MIR) ontleed ten einde die
chemiese samestelling te bepaal, en gaschromatografie-massaspektrometrie (GCMS)
is aangewend om die wynaromakomponente te bepaal. Die vlakke van glukoonsuur
is deur middel van ensiematiese reaksies bepaal. Multiveranderlike data-analise
[hoofkomponentanalise (PCA) en parsiële kleinte kwadrate (PLS1) diskriminantanalise]
is op die data van die verskeie analitiese tegnieke toegepas om onderliggende
veskille tussen die wyne van VIN13 (wilde-tipe) en VIN13-D1 uit te wys. Chemometriese
projeksies het aangetoon dat daar wel beduidende variasies sigbaar was tot en
met drie hoofkomponente en/of PLS-komponente wat duidelik aandui dat glukoonsuur
’n sleutelfaktor was ten opsigte van die uitwerking wat GOX op VIN13-D1-
fermentasies in vergelyking met VIN13-fermentasies. VIN13-D1 effek manifestasies
is die beste waargeneem op grafieke wat PLS1-diskriminantanalise-data bevat.
Verder het PLS1-diskriminantanalise ook aangetoon dat van die ‘groepe’ wat
gebruik was tydens die analise, die FT-MIR-komponente en die GC-komponente
beter resultate gelewer het. Die GC-komponente het hulle verder daartoe geleen
om tussen die verskillende kultivars en VIN13/VIN13-D1-fermentasies te diskrimineer.
Daar kan dus met sekerheid gesê word dat die grootste invloed in VIN13-D1
wyne sigbaar is in die aromakomponent, maar omdat daar wel ook variasies sigbaar
was in die MIR-komponente, dat die smaakkomponente ook beïnvloed was.
Die aktiwiteit van GOX in druiwesap is verder ondersoek deur gebruik te maak
van kleinskaalse fermentasies in bioreaktors. Daar is bevestig dat die VIN13-D1-
geproduseerde GOX biologies-aktief was tydens aerobiese kondisies, onaktief was
tydens anaerobiese kondisies, en onmiddelik geaktiveer kon word wanneer ’n anaerobiese
fermentasie aerobies gemaak word (gesimuleerde mikro-oksigenasie). Hierdie
verskillende fermentasies dui daarop dat glukose-oksidase inderdaat aktief is in
druiwesap, en dat suurstof ’n sleutelfaktor is tydens die aktivering van die ensiem.
Met behulp van ’n vereenvoudigde model kon aangetoon word dat tydens ideale
toestande dit wel moontlik is om die alkoholvlakke te verlaag na ’n voorafbepaalde
konsentrasie vir die bereiding van lae-alkohol wyne.
Hierdie studie verskaf verdere insig hoe om ’n GOX-produserende wyngis gedurende die wynmaakproses vir die verlaging van die alkoholvlakke te benut. Verder
is dit duidelik dat suurstof van kardinale belang is vir die aktivering van die glukoseoksidase-
ensiem en dat ’n tegniek soos mikro-oksigenasie ’n belangrike rol in hierdie
verband tydens die wynmaakproses sou kon speel
A Clinical Approach to Common Surgical Scenarios: A Handbook for Students and Junior Doctors
Aimed at students and junior doctors, the purpose of this book is to provide a guide to the evaluation of common surgical problems as well as test diagnostic and troubleshooting skills when there is nobody to help or ask for advice
A synoptic decomposition of rainfall over the Cape south coast of South Africa
A synoptic climatology is derived for the
Cape south coast region of South Africa by application
of the self-organizing map (SOM) technique. The SOM
is applied to average daily low-level circulation fields, as
represented by sea-level pressure anomalies for the period
1979–2011. This coastal region receives rainfall all-year
round with slight peaks during March–April and with more
pronounced peaks during August and October–November.
The synoptic forcing responsible for this annual multimodal
rainfall distribution is identified, and the relative
contribution of different synoptic types to the annual rainfall
is quantified. Ridging high pressure systems contribute
to 46 % of the annual rainfall, while tropical–temperate
troughs contribute 28 %. Cut-off lows (COLs) co-occurring
with ridging highs and tropical–temperate troughs are associated
with 16 % of the annual rainfall total. The contribution
of ridging high pressure systems decreases from south
to north, whilst the opposite is true for tropical–temperate
troughs. COLs, ridging high pressure systems and tropical–
temperate troughs are associated with the March–April
rainfall peak, while COLs are largely associated with the August rainfall peak. Ridging high pressure systems and to
a lesser extent tropical–temperate troughs, are responsible
for the October peak observed along the coast, while the
November peak over the adjacent interior regions is associated
with COLs that occur in combination with the tropical–
temperate troughs during this month.Water Research Commission (Project K5/2257/1) and the Applied Centre for Climate and Earth System Studies (ACCESS) in South Africa.http://link.springer.com/journal/3822016-05-31hb201
Projected changes in tropical cyclone climatology and landfall in the southwest Indian Ocean region under enhanced anthropogenic forcing
The conformal-cubic atmospheric model, a variable-resolution global model, is applied at high spatial resolution to perform simulations of present-day and future climate over southern Africa and over the Southwest Indian Ocean. The model is forced with the bias-corrected sea-surface temperatures and sea-ice of six coupled global climate models that contributed to Assessment Report 4 of the Intergovernmental Panel on Climate Change. All six simulations are for the period 1961–2100, under the A2 emission scenario. Projections for the latter part of the 21st century indicate a decrease in the occurrence of tropical cyclones over the Southwest Indian Ocean adjacent to southern Africa, as well as a northward shift in the preferred landfall position of these systems over the southern African subcontinent. A concurrent increase in January to March rainfall is projected for northern Mozambique and southern Tanzania, with decreases projected further south over semi-arid areas such as the Limpopo River Basin where these systems make an important contribution as main cause of widespread heavy rainfall. It is shown that the projected changes in tropical cyclone attributes and regional rainfall occur in relation to changes in larger scale atmospheric temperature, pressure and wind profiles of the southern African region and adjacent oceans.The Water Research Commission (WRC Project No. K5/1847) in South Africa, as well as the Agricultural Research Council and the Council for Scientific and Industrial Research, South Africa.http://link.springer.com/journal/382hb201
The bi-decadal rainfall cycle, Southern Annular Mode and tropical cyclones over the Limpopo River Basin, southern Africa
The association between bi-decadal rainfall variability over southern Africa and the rainfall
contributed by tropical cyclonic systems from the Southwest Indian Ocean (SWIO) provides a
potential means towards understanding decadal-scale variability over parts of the region. A
multi-decadal period is considered, focusing on the anomalous tropospheric patterns that
induced a particularly wet 8-year long sub-period over the Limpopo River Basin. The wet
sub-period was also characterized by a larger contribution to rainfall by tropical cyclones
and depressions. The findings suggest that a broadening of the Hadley circulation
underpinned by an anomalous anticyclonic pattern to the east of southern Africa altered
tropospheric steering flow, relative vorticity and moisture contents spatially during the subperiod
of 8 years. These circulation modulations induced enhanced potential for tropical
systems from the SWIO to cause precipitation over the Limpopo River Basin. The same
patterns are also conducive to increasing rainfall over the larger subcontinent, therefore
explaining the positive association in the bi-decadal rainfall cycle and rainfall contributed by
tropical cyclonic systems from the SWIO. The regional circulation anomalies are also
explained in hemispheric context, specifically in relation to the Southern Annular Mode,
towards understanding variation over other parts of the Southern Hemisphere at this time
scale.Water Research Commission (WRC Project No.K5/1847) in South Africa and the Agricultural Research Council (Project No. GW 50/053).http://link.springer.com/journal/382hb201
Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa : a historical perspective
The study provides perspective on the contribution of landfalling tropical systems (cyclones, depressions, storms and lows) from the southwest Indian Ocean (SWIO) towards rainfall over the eastern interior of southern Africa, over the period 1948-2008. Although these systems contribute to < 10% of the annual rainfall occurring over the region, their relative contribution to local and widespread heavy rainfall events is shown to be highly significant. About 50% of widespread heavy rainfall events over northeastern South Africa are caused by landfalling tropical systems. Fourier analysis performed on the time series of rainfall occurring over notheastern South Africa in association with these systems reveals the existence of a quasi-18-year cycle. The cycle coincides with the well-known quasi-18-year Dyer-Tyson cycle in rainfall over the summer rainfall region of South Africa. These results suggest that atmospheric and surface conditions leading to wet phases of the Dyer-Tyson cycle also favour the landfall and subsequent westward movement of tropical systems from the SWIO over southern Africa – and their eventual contribution to rainfall over northeastern South Africa and southern Zimbabwe.Water Research Commission,
South Africa (WRC Project No. K5/1847).http://www3.interscience.wiley.com/journal/4735/hom
Diagnostic accuracy of the Xpert MTB/Rif Ultra for tuberculosis adenitis
Abstract
Background
The WHO recently recommended the new Xpert MTB/RIF Ultra assay (Ultra) instead of the Xpert MTB/RIF assay because Ultra has improved sensitivity. We report the diagnostic accuracy of Ultra for tuberculous adenitis in a tuberculosis and HIV endemic setting.
Methods
We obtained fine-needle aspirates (FNA) and lymph node tissue by core-needle biopsy in adult patients with peripheral lymphadenopathy of >20 mm. Ultra and mycobacterial culture were performed on FNA and tissue specimens, with histological examination of tissue specimens. We assessed the diagnostic accuracy of Ultra against a composite reference standard of ‘definite tuberculosis’ (microbiological criteria) or ‘probable tuberculosis’ (histological and clinical criteria).
Results
We prospectively evaluated 99 participants of whom 50 were HIV positive: 21 had ‘definite tuberculosis’, 15 ‘probable tuberculosis’ and 63 did not have tuberculosis (of whom 38% had lymphoma and 19% disseminated malignancy). Using the composite reference standard the Ultra sensitivity on FNA was 70% (95% CI 51–85; 21 of 30), and on tissue was 67% (45–84; 16/24) these were far superior to the detection of acid-fast bacilli on an FNA (26%; 7/27); AFB on tissue (33%; 8/24); or tissue culture (39%; 9/23). The detection of granulomas on histology had high senstivity (83%) but the lowest specficity. When compared with culture the Ultra on FNA had a sensitvity of 78% (40-97; 7/9) and tissue 90% (55-100; 9/10).
Conclusions
Ultra performed on FNA or tissue of a lymph node had good sensitivity and high specificity. Ultra had a higher yield than culture and has the advantage of being a rapid test. Ultra on FNA would be an appropriate initial investigation for lymphadenopathy in tuberculosis endemic areas followed by a core biopsy for histopathology with a repeat Ultra on tissue if granulomas are present
Fabrication of Ti14Nb4Sn alloys for bone tissue engineering applications
In this paper, porous Ti14Nb4Sn alloys were fabricated using a space holder sintering method, resulting in a porosity of ~70%. Scanning electron microscopy (SEM) analyses revealed a
combination of both macropore and micropore structures. The fabricated titanium alloy scaffolds exhibited a similar structure to that of natural bone, which is expected to improve bone implant longevity. Bacterial cells of Pseudomonas aeruginosa ATCC 9027 were employed for the in vitro test
Fabrication of Ti14Nb4Sn Alloys for Bone Tissue Engineering Applications
In this paper, porous Ti14Nb4Sn alloys were fabricated using a space holder sintering method, resulting in a porosity of ~70%. Scanning electron microscopy (SEM) analyses revealed a combination of both macropore and micropore structures. The fabricated titanium alloy scaffolds exhibited a similar structure to that of natural bone, which is expected to improve bone implant longevity. Bacterial cells of Pseudomonas aeruginosa ATCC 9027 were employed for the in vitro test
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