79 research outputs found

    A determination of the key factors and characteristics that SME-scale commercial biomedical ventures require to succeed in the South African environment

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    The potential for private sector healthcare business in Africa has been forecasted to reach $35 billion by 2016, with South Africa being regarded as the most industrially advanced country on the continent. South Africa’s entry to modern biotechnology is fairly recent, though, with companies in the private sector still in a developmental phase, and most having limited bioproduct ranges. While considerable research has been conducted in the past to attempt to define the biotechnology environment of South Africa, as yet, a concise overview is lacking. In particular, a synopsis of the biomedical or commercial health technology environment has not been forthcoming for entrepreneurs to refer to as a ‘roadmap’. The purpose of this study was to perform a comprehensive study on the attributes that should be met for a successful, sustainable health technology venture (HTV) to be started in South Africa; while identifying the opportunities and threats that have existed in the South African market; thereby, affecting their success and sustainability to date. In this study, two phases of research were conducted. The first was a small-sampled mixed-methods (both qualitative and quantitative) study involving 21 medical devices, biogenerics, diagnostics, and contract services companies. The second was a quantitative study, involving 107 vaccines, biogenerics, therapeutics, nutraceuticals, reagents, diagnostics, medical devices, biotools, contract services and public services companies. Inferential statistical tests were conducted on the data, including Pearson’s Chi-Square, ANOVA, bivariate correlation, linear regression, logistic regression and multinomial logistic regression. From the study, the overall proportion of business sustainability for HTVs was found to be 66.7%, and at least 30% were unsustainable (or not yet at a level of sustainability). Variations were observed in the overall rate of sustainability for companies, based on their core functional classification, location, production type, size and start-up or R&D spending. By converting the observed frequencies of activity level, as an indication of sustainability, into a probability, it was possible to observe the company type that was most, and least likely to succeed in South Africa. Based on the statistical observations in this study, the HTV type most likely to succeed in South Africa, with a 63.7% probability of reaching sustainability, is a ‘vaccines’, ‘biotools’ or ‘public services’ company from Johannesburg with at least 20 employees; that has developed its goods or services internally, but manufactured externally and spent between R20 million–and–R30 million on its R&D or start-up. Conversely, least likely to succeed (3.2% probability) is a nutraceutical company from Cape Town with between six and 20 employees, that has developed and produced internally, and which has spent between R1 million–and–R10million on its start-up.Life and Consumer SciencesM. Sc. (Life Sciences

    The CHROMA cloud top pressure retrieval algorithm for the Plankton, Aerosol, Cloud, ocean Ecosytem (PACE) satellite mission

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    This paper provides the theoretical basis and simulated retrievals for the Cloud Height Retrieval from O2 Molecular Absorption (CHROMA) algorithm. Simulations are performed for the Ocean Color Instrument (OCI), which is the primary payload on the forthcoming NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission, and the Ocean Land Colour Instrument (OLCI) currently flying on the Sentinel 3 satellites. CHROMA is a Bayesian approach which simultaneously retrieves cloud optical thickness (COT), cloud top pressure/height (CTP/CTH), and (with a significant prior constraint) surface albedo. Simulated retrievals suggest that the sensor and algorithm should be able to meet the PACE mission goal for CTP error, which is +/-60 mb for 65 % of opaque (COT > 3) single-layer clouds on global average. CHROMA will provide pixel-level uncertainty estimates, which are demonstrated to have skill at telling low-error situations from high-error ones. CTP uncertainty estimates are well-calibrated in magnitude, although COT uncertainty is overestimated relative to observed errors. OLCI performance is found to be slightly better than OCI overall, demonstrating that it is a suitable proxy for the latter in advance of PACE’s launch. CTP error is only weakly sensitive to correct cloud phase identification or assumed ice crystal habit/roughness. As with other similar algorithms, for simulated retrievals of multi-layer systems consisting of optically thin cirrus clouds above liquid clouds, retrieved height tends to be underestimated because the satellite signal is dominated by the optically-thicker lower layer. Total (liquid plus ice) COT also becomes underestimated in these situations. However, retrieved CTP becomes closer to that of the upper ice layer for ice COT approx 3 or higher

    Predicting Survival of NSCLC Patients Treated with Immune Checkpoint Inhibitors: Impact and Timing of Immune-related Adverse Events and Prior Tyrosine Kinase Inhibitor Therapy

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    Introduction: Immune checkpoint inhibitors (ICIs) produce a broad spectrum of immune-related adverse events (irAEs) affecting various organ systems. While ICIs are established as a therapeutic option in non-small cell lung cancer (NSCLC) treatment, most patients receiving ICI relapse. Additionally, the role of ICIs on survival in patients receiving prior targeted tyrosine kinase inhibitor (TKI) therapy has not been well-defined. Objective: To investigate the impact of irAEs, the relative time of occurrence, and prior TKI therapy to predict clinical outcomes in NSCLC patients treated with ICIs. Methods: A single center retrospective cohort study identified 354 adult patients with NSCLC receiving ICI therapy between 2014 and 2018. Survival analysis utilized overall survival (OS) and real-world progression free survival (rwPFS) outcomes. Model performance matrices for predicting 1-year OS and 6-month rwPFS using linear regression baseline, optimal, and machine learning modeling approaches. Results: Patients experiencing an irAE were found to have a significantly longer OS and rwPFS compared to patients who did not (median OS 25.1 vs. 11.1 months; hazard ratio [HR] 0.51, confidence interval [CI] 0.39- 0.68, P-value \u3c0.001, median rwPFS 5.7 months vs. 2.3; HR 0.52, CI 0.41- 0.66, P-value \u3c0.001, respectively). Patients who received TKI therapy before initiation of ICI experienced significantly shorter OS than patients without prior TKI therapy (median OS 7.6 months vs. 18.5 months; P-value \u3c 0.01). After adjusting for other variables, irAEs and prior TKI therapy significantly impacted OS and rwPFS. Lastly, the performances of models implementing logistic regression and machine learning approaches were comparable in predicting 1-year OS and 6-month rwPFS. Conclusion: The occurrence of irAEs, the timing of the events, and prior TKI therapy were significant predictors of survival in NSCLC patients on ICI therapy. Therefore, our study supports future prospective studies to investigate the impact of irAEs, and sequence of therapy on the survival of NSCLC patients taking ICIs

    Coronary artery height differences and their effect on fractional flow reserve

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    Background: Fractional flow reserve (FFR) uses pressure-based measurements to assess the severityof a coronary stenosis. Distal pressure (Pd) is often at a different vertical height to that of the proximalaortic pressure (Pa). The difference in pressure between Pd and Pa due to hydrostatic pressure, mayimpact FFR calculation.Methods: One hundred computed tomography coronary angiographies were used to measure heightdifferences between the coronary ostia and points in the coronary tree. Mean heights were used to calculate the hydrostatic pressure effect in each artery, using a correction factor of 0.8 mmHg/cm. Thiswas tested in a simulation of intermediate coronary stenosis to give the “corrected FFR” (cFFR) andpercentage of values, which crossed a threshold of 0.8.Results: The mean height from coronary ostium to distal left anterior descending (LAD) was +5.26 cm,distal circumflex (Cx) –3.35 cm, distal right coronary artery-posterior left ventricular artery (RCA-PLV)–5.74 cm and distal RCA-posterior descending artery (PDA) +1.83 cm. For LAD, correction resulted in a mean change in FFR of +0.042, –0.027 in the Cx, –0.046 in the PLV and +0.015 in the PDA. Using 200 random FFR values between 0.75 and 0.85, the resulting cFFR crossed the clinical treatmentthreshold of 0.8 in 43% of LAD, 27% of Cx, 47% of PLV and 15% of PDA cases.Conclusions: There are significant vertical height differences between the distal artery (Pd) and its point of normalization (Pa). This is likely to have a modest effect on FFR, and correcting for this results in a proportion of values crossing treatment thresholds. Operators should be mindful of this phenomenon when interpreting FFR values

    Pond ecology and conservation: research priorities and knowledge gaps

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    Ponds are among the most biodiverse and ecologically important freshwater habitats globally and may provide a significant opportunity to mitigate anthropogenic pressures and reverse the decline of aquatic biodiversity. Ponds also provide important contributions to society through the provision of ecosystem services. Despite the ecological and societal importance of ponds, freshwater research, policy, and conservation have historically focused on larger water bodies, with significant gaps remaining in our understanding and conservation of pond ecosystems. In May 2019, pond researchers and practitioners participated in a workshop to tackle several pond ecology, conservation, and management issues. Nine research themes and 30 research questions were identified during and following the workshop to address knowledge gaps around: (1) pond habitat definition; (2) global and long-term data availability; (3) anthropogenic stressors; (4) aquatic–terrestrial interactions; (5) succession and disturbance; (6) freshwater connectivity; (7) pond monitoring and technological advances; (8) socio-economic factors; and (9) conservation, management, and policy. Key areas for the future inclusion of ponds in environmental and conservation policy were also discussed. Addressing gaps in our fundamental understanding of pond ecosystems will facilitate more effective research-led conservation and management of pondscapes, their inclusion in environmental policy, support the sustainability of ecosystem services, and help address many of the global threats driving the decline in freshwater biodiversity
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