| 1. |
- Thomas, HS, et al.
(author)
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- 2019
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swepub:Mat__t
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| 2. |
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| 3. |
- Abulfathi, Ahmed Aliyu, et al.
(author)
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Clinical Pharmacokinetics and Pharmacodynamics of Rifampicin in Human Tuberculosis
- 2019
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In: Clinical Pharmacokinetics. - : Springer Science and Business Media LLC. - 0312-5963 .- 1179-1926. ; 58:9, s. 1103-1129
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Research review (peer-reviewed)abstract
- The introduction of rifampicin (rifampin) into tuberculosis (TB) treatment five decades ago was critical for shortening the treatment duration for patients with pulmonary TB to 6months when combined with pyrazinamide in the first 2months. Resistance or hypersensitivity to rifampicin effectively condemns a patient to prolonged, less effective, more toxic, and expensive regimens. Because of cost and fears of toxicity, rifampicin was introduced at an oral daily dose of 600mg (8-12mg/kg body weight). At this dose, clinical trials in 1970s found cure rates of >= 95% and relapse rates of < 5%. However, recent papers report lower cure rates that might be the consequence of increased emergence of resistance. Several lines of evidence suggest that higher rifampicin doses, if tolerated and safe, could shorten treatment duration even further. We conducted a narrative review of rifampicin pharmacokinetics and pharmacodynamics in adults across a range of doses and highlight variables that influence its pharmacokinetics/pharmacodynamics. Rifampicin exposure has considerable inter- and intra-individual variability that could be reduced by administration during fasting. Several factors including malnutrition, HIV infection, diabetes mellitus, dose size, pharmacogenetic polymorphisms, hepatic cirrhosis, and substandard medicinal products alter rifampicin exposure and/or efficacy. Renal impairment has no influence on rifampicin pharmacokinetics when dosed at 600mg. Rifampicin maximum (peak) concentration (C-max) > 8.2 mu g/mL is an independent predictor of sterilizing activity and therapeutic drug monitoring at 2, 4, and 6h post-dose may aid in optimizing dosing to achieve the recommended rifampicin concentration of >= 8 mu g/mL. A higher rifampicin C-max is required for severe forms TB such as TB meningitis, with C-max >= 22 mu g/mL and area under the concentration-time curve (AUC) from time zero to 6h (AUC(6)) >= 70 mu g.h/mL associated with reduced mortality. More studies are needed to confirm whether doses achieving exposures higher than the current standard dosage could translate into faster sputum conversion, higher cure rates, lower relapse rates, and less mortality. It is encouraging that daily rifampicin doses up to 35mg/kg were found to be safe and well-tolerated over a period of 12weeks. High-dose rifampicin should thus be considered in future studies when constructing potentially shorter regimens. The studies should be adequately powered to determine treatment outcomes and should include surrogate markers of efficacy such as C-max/MIC (minimum inhibitory concentration) and AUC/MIC.
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| 4. |
- Audet, Carolyn M., et al.
(author)
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An unrecognized key population? : Traditional treatment practices associated with HIV risk among traditional healers in rural South Africa
- 2020
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In: AIDS. - : Lippincott Williams & Wilkins. - 0269-9370 .- 1473-5571. ; 34:15, s. 2313-2317
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Journal article (peer-reviewed)abstract
- Objective: To understand the risk of HIV acquisition through occupational exposure among rural South African traditional healers, notably via the practice of traditional skin incisions with razors.Design: A random sample of traditional healers living in South Africa participated in a cross-sectional survey that included a rapid HIV test.Setting: Rural Bushbuckridge district of Mpumalanga, South Africa.Participants: Traditional healers.Intervention: Pretest counseling, posttest counseling, and referral to care if HIV seropositive.Main outcome measure(s): HIV infection.Results: Among healers who reported a previous positive test result or accepted an HIV test (96%), HIV prevalence was 30% (95% confidence interval: 23–37%). During their careers, 98% of healers reported conducting at least one ‘vaccination’ (as traditional incisions are called), 32% reported always using gloves when conducting these procedures, 29 (14%) reported patient blood touching their bare skin. Healers who reported exposure to patient blood had a higher HIV prevalence than their nonexposed colleagues (adjusted risk ratio: 2.35, 95% confidence interval: 1.55–3.56, P = 0.001).Conclusion: Nearly all traditional healers are routinely performing minimally invasive skin incisions that could expose them to patient blood. The lack of training and access to personal protective equipment increase their risk of acquisition of blood–borne pathogens, including HIV. Given the widespread practice of traditional skin incisions across southern Africa, and the higher levels of HIV among traditional healers exposed to patient blood, it is likely that traditional healers are a hitherto unrecognized key population at disproportionate risk of acquiring HIV.
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| 5. |
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| 6. |
- Vanfretti, Luigi, et al.
(author)
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Application of ambient analysis techniques for the estimation of electromechanical oscillations from measured PMU data in four different power systems
- 2011
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In: European transactions on electrical power. - : Wiley-Blackwell. - 1430-144X .- 1546-3109. ; 21:4, s. 1640-1656
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Journal article (peer-reviewed)abstract
- The application of advanced signal processing techniques to power system measurement data for the estimation of dynamic properties has been a research subject for over two decades. Several techniques have been applied to transient (or ringdown) data, ambient data, and to probing data. Some of these methodologies have been included in off-line analysis software, and are now being incorporated into software tools used in control rooms for monitoring the near real-time behavior of power system dynamics. In this paper we illustrate the practical application of some ambient analysis methods for electromechanical mode estimation in different power systems. We apply these techniques to phasor measurement unit (PMU) data from stored archives of several hours originating from the US Eastern Interconnection (EI), the Western Electricity Coordinating Council (WECC), the Nordic Power System, and time-synchronized Frequency Disturbance Recorder (FDR) data from Nigeria. It is shown that available signal processing tools are readily applicable for analysis of different power systems, regardless of their specific dynamic characteristics. The discussions and results in this paper are of value to power system operators and planners as they provide information of the applicability of these techniques via readily available signal processing tools, and in addition, it is shown how to critically analyze the results obtained with these methods.
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| 7. |
- Vanfretti, Luigi, et al.
(author)
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Building a Frequency Monitoring Network to Study Dynamics of Small-Scale Power Systems
- 2007
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In: Proceedings of the 7th International Conference on Power System Operations and Planning (ICPSOP) 2007. - : ICPSOP.
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Conference paper (peer-reviewed)abstract
- Frequency is one of the most important measures of the status of a power system, especially for weak and smallscale po systems. Therefore, frequency monitoring is a desirable practice to ensure reliability and provide data for analysis. This paper reports the joint work between Rensselaer Polytechnic Institute (RPI) and Abubakar Tafawa Balewa University (ATBU) to study frequency dynamics of small power systems. We describe the Frequency Disturbance Recorder (FDR) implementation experience at ATBU, Bauchi, Nigeria, and present analysis on the digital recordings provided by the FDR installed at this location. A proposal for a university-based FNET for Nigeria’s power system is also presented. Such monitoring system will allow further investigations on the Nigerian system dynamics and will enhance the understanding of dynamics and control of weak small-scale power systems.
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| 8. |
- Vanfretti, Luigi, et al.
(author)
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Estimation of the Nigerian Power System Electromechanical Modes using FDR Measurements
- 2010
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In: Proceedings of the 9th International Conference on Power System Operations and Planning (ISCPSOP) 2010.
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Conference paper (peer-reviewed)abstract
- This paper reports on an ongoing research effort between researchers in North America and Africa on the study of the dynamics of loosely regulated and rapidly growing power systems, with focus on the Nigerian power network. A description of the implementation of Virginia Tech’s FDR (Frequency Disturbance Recorder) at Bauchi, Nigeria is provided. We discuss the nature of the frequency dynamics observed throughout multiple hours of a day in Nigeria and other power systems. To cater to the loosely regulated nature of the system frequency in Nigeria, we propose an appropriate method for signal conditioning which prepares the data for ambient analysis. Parametric and nonparametric block processing techniques are applied to prolonged frequency recordings ranging from 8 to 19 hours, and estimates of modal frequencies and damping are obtained by computing power spectrum densities and applying a mode meter algorithm to the ambient data. The estimated modes from ambient analysis are in agreement with other studies based on power system models.
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| 9. |
- Vanfretti, Luigi, et al.
(author)
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Modelling of a System Collapse in the Nigerian National Power System using Frequency Disturbance Recorder Data
- 2012
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In: 9th International Conference on Power System Operations adn Planning (ICPSOP) 2012. ; , s. 1-6
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Conference paper (peer-reviewed)abstract
- This paper exploits the availability of frequency disturbance recorder (FDR) measurements and knowledge of the underlying operational data from the Nigerian National Power System to develop a model capable of reproducing the most important characteristics of one of the many collapses in the Nigerian grid during the last recent years.The collapse investigated in this paper was captured on December 2nd , 2006, with an FDR unit installed at Abubakar Tafawa Balewa University (ATBU). Using operational information from the National Control Center (NCC) at Osogbo, three models representing the Nigerian power system were developed to capture the most relevant dynamics of the grid during the cascading failure. These models include both detailed representations of the different network components, as well as average frequency dynamics only.Comprehensive simulation results show how the models are capable of representing the most important features of the collapse of the system, and hence, their continuous improvement through model validation may allow their use in the development of load shedding mechanisms which are needed for mitigating cascading failures in the Nigerian system.
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| 10. |
- Vanfretti, Luigi, et al.
(author)
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System frequency monitoring in the Nigerian power system
- 2009
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In: 2009 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, VOLS 1-8. - : IEEE. - 9781424442409 ; , s. 2301-2306
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Conference paper (peer-reviewed)abstract
- Frequency is one of the most important measures of the state of a power system, especially for structurally weak and rapidly growing power systems. Thus, frequency monitoring is a desirable practice to ensure reliability and provide data for analysis. This paper reports the joint work between Abubakar Tafawa Balewa University (ATBU) and Rensselaer Polytechnic Institute (RPI) to study frequency dynamics of a relative small power system. We describe the frequency disturbance recorder (FDR) implementation experience at ATBU, Bauchi, Nigeria, and present analysis on the digital recordings obtained by the FDR. A proposal for a university-based frequency monitoring network for the Nigerian power system is also presented. Such monitoring system will allow further investigations on the Nigerian system and ultimately enhance the understanding of the dynamics and control of structurally weak and rapidly growing power systems found in many developing countries.
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