Publications by authors named "Nieuwoudt M"

Piezoelectric organic polymers are promising alternatives to their inorganic counterparts due to their mechanical flexibility, making them suitable for flexible and wearable piezoelectric devices. Biological polymers such as proteins have been reported to possess piezoelectricity, while offering additional benefits, such as biocompatibility and biodegradability. However, questions remain regarding protein piezoelectricity, such as the impact of the protein secondary structure.

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Chemometrics; use of statistical models to characterise and understand complex chemical systems/samples, is an advancing field. In the dairy industry, the accurate prediction of milk composition involves combining mid-infrared spectroscopy with chemometric techniques for the evaluation of major constituents of milk. The increased interest in determination of detailed composition of dairy products, alongside emerging and more-widespread use of chemometric methodologies, have generated continuous improvement in predictive models for this application.

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Article Synopsis
  • Limited data on South African children hospitalized with COVID-19 exist, particularly in lower-level district hospitals.
  • The study finds that young age, especially in infants exposed to HIV or born prematurely, significantly increases the risk of severe COVID-19 hospitalization.
  • A notable number of children admitted also have tuberculosis, indicating a concerning link between viral infections like COVID-19 and childhood tuberculosis.
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The exquisite sensitivity of Raman spectroscopy for detecting biomolecular changes in skin cancer has previously been explored; however, this mostly required analysis of excised tissue samples using bulky, immobile laboratory instrumentation. In this study, the technique was translated for clinical use with a portable Raman system and customized fiber optic probe and applied to differentiation of skin cancers from benign lesions and inflammatory dermatoses. The aim was to provide an easy-to-use, easy-to-manage assessment tool for clinicians to use in their daily patient examination routine to perform rapid Raman measurements of skin lesions in vivo.

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Discoid lupus erythematosus (DLE) is the most common form of cutaneous lupus. It can cause permanent scarring. The pathophysiology of is not fully understood.

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In this study, we utilize nanosecond and femtosecond direct laser writing for the generation of hydrophobic and hydrophilic microfluidic valves on a centrifugal microfluidic disk made of polycarbonate, without the need for wet-chemistry. Application of a femtosecond (fs) laser at 800 nm resulted in an increased contact angle, from ∼80° to ∼160°, thereby inducing the formation of a hydrophobic surface. In contrast, employing a nanosecond (ns) laser at 248 nm led to the formation of superhydrophilic surfaces.

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Recent years have witnessed a significant advancement in brain imaging techniques that offer a non-invasive approach to mapping the structure and function of the brain. Concurrently, generative artificial intelligence (AI) has experienced substantial growth, involving using existing data to create new content with a similar underlying pattern to real-world data. The integration of these two domains, generative AI in neuroimaging, presents a promising avenue for exploring various fields of brain imaging and brain network computing, particularly in the areas of extracting spatiotemporal brain features and reconstructing the topological connectivity of brain networks.

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Photoinduced enhanced Raman spectroscopy (PIERS) is a new surface enhanced Raman spectroscopy (SERS) modality with a 680% Raman signal enhancement of adsorbed analytes over that of SERS. Despite the explosion in recent demonstrations, the PIERS mechanism remains undetermined. Using X-ray and time-resolved optical spectroscopies, electron microscopy, cyclic voltammetry, and density functional theory simulations, we elucidate the atomic-scale mechanism behind PIERS.

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Prostate cancer (PCa) is a significant healthcare problem worldwide. Current diagnosis and treatment methods are limited by a lack of precise in vivo tissue analysis methods. Real-time cancer identification and grading could dramatically improve current protocols.

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Objective: Stress can play a role in the onset and exacerbation of psoriasis. Psychological interventions to reduce stress have been shown to improve psychological and psoriasis-related outcomes. This pilot randomised study investigated the feasibility of a brief interaction with a Paro robot to reduce stress and improve skin parameters, after a stressor, in patients with psoriasis.

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Sustained release of lidocaine from poly ethylene-co-vinyl acetate (EVA) implants can significantly improve pain management outcomes; however, poor drug loading is a major limitation. Recently, myristic acid was found to improve drug loading in EVA by inhibiting the crystallization of lidocaine. Here, lidocaine's interaction with myristic acid was studied by differential scanning calorimetry.

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Raman spectroscopy has long been suggested as a potentially fast and sensitive method to monitor phytoplankton abundance and composition in marine environments. However, the pitfalls of visible detection methods in pigment-rich biological material and the complexity of their spectra have hindered their application as reliable detection methods. In this study we combine 1064 nm confocal Raman spectroscopy with multivariate statistical analysis techniques (principle component analysis and partial leas-squares discriminant analysis) to reliably measure differences in the cell viability of a diatom species () and two haptophyte species ( and ) of phytoplankton.

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Mid-infrared spectroscopy has been developed as a reliable and rapid tool for routine analysis of fat, protein, lactose and other components in liquid milk. However, variations within and between FTIR instruments, even within the same milk testing laboratory, present a challenge to the accuracy of measurement of particularly minor components in the milk, such as individual fatty acids or proteins. In this study we have used Analysis of variance-Simultaneous Component Analysis (ASCA), to monitor the spectral variation between and within each of four different FOSS FTIR spectrometers over each week in an independent milk testing laboratory over 4 years, between August 2017 and March 2021 (223 weeks).

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Synthetic polymeric materials have demonstrated great promise for bone tissue engineering based on their compatibility with a wide array of scaffold-manufacturing techniques, but are limited in terms of the bioactivity when compared to naturally occurring materials. To enhance the regenerative properties of these materials, they are commonly functionalised with bioactive factors to guide growth within the developing tissue. Extracellular matrix vesicles (EVs) play an important role in facilitating endochondral ossification during long bone development and have recently emerged as important mediators of cell-cell communication coordinating bone regeneration, and thus represent an ideal target to enhance the regenerative properties of synthetic scaffolds.

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During the process of studying some morphological characters of fish found in the food of the Australasian gannet Morus serrator breeding at Horuhoru Rock and Mahuki islands in the Hauraki Gulf, New Zealand, one carangid specimen of fish species Trachurus declivis out of the 25 fish specimens examined revealed seven small plastic particles in its stomach of different colours: black, red, blue, green, and transparent. Fourier transform infrared (FTIR) spectroscopy was used to identify the compositions of the particles as low and high density polyethylene, poly (methyl methacrylate), polypropylene, and a copolymer of butadiene, acrylonitrile, and methacrylamide. The plastic particles comprised several different shapes and sizes, ranging between 4.

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Long-term effects of the growing population of HIV-treated people in Southern Africa on individuals and the public health sector at large are not yet understood. This study proposes a novel 'ratio' model that relates CD4+ T-cell counts of HIV-infected individuals to the CD4+ count reference values from healthy populations. We use mixed-effects regression to fit the model to data from 1616 children (median age 4.

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Bone strength in human cortical bone is determined by the composition and structure of both the mineral and collagen matrices and influenced by factors such as age, gender, health, lifestyle and genetic factors. Age-related changes in the bone matrix are known to result in loss of mechanical strength and increased fragility. In this study we show how Raman spectroscopy, with its exquisite sensitivity to the molecular structure of bone, reveals new insights into age- and sex-related differences.

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Typically, African healthcare providers use immunological reference intervals adopted from Europe and the United States (US). This may be inappropriate in a setting with many differences including exposure to different environmental stimuli and pathogens. We compared immunological reference intervals for children from Europe and the US with South African children to explore whether healthy children living in settings with high rates of infectious diseases have different baseline immunological parameters.

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Introduction: There are Challenges in statistically modelling immune responses to longitudinal HIV viral load exposure as a function of covariates. We define Bayesian Markov Chain Monte Carlo mixed effects models to incorporate priors and examine the effect of different distributional assumptions. We prospectively fit these models to an as-yet-unpublished data from the Tshwane District Hospital HIV treatment clinic in South Africa, to determine if cumulative log viral load, an indicator of long-term viral exposure, is a valid predictor of immune response.

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In vivo and ex vivo sensors have the potential to aid tracking and anti-poaching endeavours and provide new insights into rhinoceros physiology and environment. However, the propagation of electromagnetic signals in rhinoceros tissue is currently not known. We present simulation and agar models of the rhinoceros that allow the investigation of electromagnetic propagation by in vivo and ex vivo devices without the need for surgery.

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Correction for 'Unexpected arene ligand exchange results in the oxidation of an organoruthenium anticancer agent: the first X-ray structure of a protein-Ru(carbene) adduct' by Matthew P. Sullivan et al., Chem.

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Background: Several studies in developed countries have demonstrated high levels of iron deficiency (ID) among blood donors. There is a paucity of data for developing countries where blood shortages remain a major concern.

Study Design And Methods: A total of 4412 donors were enrolled in the study.

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Polyaniline (PANI) and functionalised polyanilines (fPANI) are novel antimicrobial agents whose mechanism of action was investigated. single gene deletion mutants revealed that the antimicrobial mechanism of PANI likely involves production of hydrogen peroxide while homopolymer poly(3-aminobenzoic acid), P3ABA, used as an example of a fPANI, disrupts metabolic and respiratory machinery, by targeting ATP synthase and causes acid stress. PANI was more active against in aerobic, compared to anaerobic, conditions, while this was apparent for P3ABA only in rich media.

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