1,721,012 research outputs found
CRISPR/Cas-enabled paper microfluidic device to detect SARS- CoV-2 and its variants for wastewater-based epidemiology
No full textCullen, David C. - Associate SupervisorWastewater-based epidemiology (WBE) has been demonstrated to be a
powerful tool for monitoring public health through the detection of biomarkers,
such as drugs and pathogens, in wastewater. During the COVID-19 pandemic,
it evolved into a significant supplementary approach to clinical diagnostics,
offering capabilities as an early warning system, enabling population-level
infection monitoring, and tracking down the virus including the variants of
concern. However, current methods for wastewater analysis are heavily
dependent on the centralized laboratory which requires expensive equipment,
specialized personnel, and result in slow turnround. This thesis addresses
these critical challenges by developing innovative approaches for the detection
of SARS-CoV-2 and its variants, combining molecular diagnostics with field-
deployable paper microfluidic devices. A comparative analysis of polyethylene
glycol (PEG) precipitation and ultrafiltration for concentrating SARS-CoV-2
RNA from wastewater led to the development of an optimized protocol suitable
for routine analysis. This protocol was applied for long-term monitoring of viral
loads (N-gene) in a local wastewater treatment plant, providing valuable
insights into infection trends. Additionally, a CRISPR/Cas12a-based
fluorescent assay was developed to detect SARS-CoV-2 and its variants with
high specificity and sensitivity, able to detect as low as 5 copies µL¯¹ . To enable
on-site diagnostics, a portable paper microfluidic device was designed,
integrating the optimized concentration methods and CRISPR/Cas12a assays.
The device demonstrated a rapid detection of wastewater within 90 minutes for
SARS-CoV-2 even without laboratory settings. This research findings advances
WBE by bridging the gap between laboratory-based techniques and in-field
testing. The technology provides a scalable, cost-effective platform for rapid
and onsite monitoring SARS-CoV-2 and other pathogens, contributing
significantly to global health management, particularly in resource-limited
settings.PhD in Wate
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Development of life marker chip technology for in-situ life detection on Mars
Full text linkThe European Space Agency (ESA) is currently developing its flagship Life Detection Mission, ExoMars, which is scheduled to fly to Mars in 2013. The primary goal of this mission is to compliment the Phoenix NASA mission in confirming the presence of organic material on Mars, and, for the first time, analyse this organic material to determine the presence of organic species indicative of presence of past or present Life. One of the proposed Life detection technologies is the Life Marker Chip (LMC), which uses immunoassays with fluorescent readout to detect small organics and proteins in a microarray format within microfluidic channel structures. This PhD thesis encompasses the work done by the author on the development of the SMILE LMC during the period prior to, and during part of the first phase of, the Life Marker Chip Technology Readiness Level Upgrade Study funded by ESA from 2005 and 2007. Cont/d
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Development of a fluidic sensor for the detection of herbicides using thylakoid preparations immobilised on magnetic beads to aid regenerability
Full text linkFollowing the industrial revolution and advances in chemical science, the
pollution of the environment with trace organic pollutants has been steadily
increasing, which is of concern, due to their effect on the environmental and
human health. Tighter legislation that has been introduced in order to minimise
the release of harmful pollutants has led to the initiation of monitoring
programmes. For example, drinking water suppliers are obliged to
systematically monitor drinking water supplied for human consumption for a
large range of pollutants. The same applies for waste water treatment facilities.
The well-established standard methods of environmental waters analysis
require sampling and transportation of samples to the laboratory for detailed
measurements. Therefore, the timescale from sampling to reporting is not ideal,
as a considerable lag occurs.
There is therefore the potential for the use of in situ methods that overcome this
issue. As these do not currently exist, a need to address this is identified.
Biosensors are sensing devices that rely on a biologically-derived component
as an integral part of their detection mechanism. Biosensors that respond to
pollutants could be used for rapid, low cost, field-based pre-screening of water
samples.
Herbicides are considered to be the most important class of pesticides used in
the E.U. Herbicides can be highly toxic for human and animal health, and
increase in the application of herbicides in agriculture during recent decades
has resulted in immense pollution of both soil and water. About half of the
herbicides used at present in agriculture inhibit the light reactions in
photosynthesis, mostly by targeting the Photosystem II (PSII) complex.
A method of detecting certain classes of herbicides is therefore proposed; the
photosynthesis-inhibiting herbicides act by binding to PS II, a chlorophyll–
protein complex which plays a vital role in photosynthesis, located in the
thylakoid membrane of algae, cyanobacteria and higher plants. The inhibition of
PS II causes a reduced photoinduced production of hydrogen peroxide, which
can be measured by the HRP-mediated luminol chemiluminescence reaction.
The design and development of a fluidic sensor unit for the detection of such
herbicides, based upon their inhibition of the hydrogen peroxide production, will
employ the use of superparamagnetic beads in order to address issues of reuse
and regenerability.
The illumination-dependent production of hydrogen peroxide by isolated
thylakoids, and its inhibition by herbicides in a concentration-dependent
manner, were achieved and measured with the HRP-mediated
chemiluminescence reaction with luminol in a cuvette, batch format, allowing for
the detection of herbicides down to 6.0 x 10-09.The integration of the above reactions has been achieved by designing and
constructing a fluidic unit that combines the herbicide-dependent production and
the detection of hydrogen peroxide in a single fluidic assay by combining all the
individual steps in a compact, portable format, with both HRP and thylakoids
covalently coupled on superparamagnetic beads. This addresses issues of
regenerability, as the beads are introduced, used and discarded following a
measurement, controlled only by magnetic and flow forces. Herbicide detection
was achieved to a lower LOD of 5.5 x 10-10 M. The concept development,
design and construction of the fluidic unit, as well as results of the detection of
herbicides with the batch assay method has been published, in a paper by the
author (Talanta, 2008, vol. 77, no. 1, pp. 42-47),
Considerable progress has therefore been made towards developing a system
that would be suitable for automated, field deployment applications for the
detection of the most frequently used classes of herbicides; the lower LOD
however is not within the stringent legislated maximum permissible limits set for
herbicides measured in water, in European waters.
An immediate step forward would be to achieve the required lower LOD, with
the unit's development into a prototype instrument that can be field deployed
being the further goal
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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