scholarly journals Characterisation of prosthetic feet used in low-income countries

2004 ◽  
Vol 28 (2) ◽  
pp. 132-140 ◽  
Author(s):  
M. Sam ◽  
A. H. Hansen ◽  
D. S. Childress

Eleven kinds of prosthetic feet that were designed for use in low-income countries were mechanically characterised in this study. Masses of the different kinds of prosthetic feet varied substantially. Dynamic properties, including damping ratios and resonant frequencies, were obtained from step unloading tests of the feet while interacting with masses comparable to the human body. Data showed that for walking, the feet can be appropriately modeled using their quasistatic properties since natural frequencies were high compared to walking frequencies and since damping ratios were small. Roll-over shapes, the effective rocker (cam) geometries that the feet deform to under walking loads, were determined using a quasistatic loading technique and a spatial transformation of the ground reaction force's centre of pressure. The roll-over shapes for most of the prosthetic feet studied were similar to the roll-over shape of the SACH (solid-ankle cushioned heel) prosthetic foot. All roll-over shapes showed a lack of forefoot support, which may cause a “drop-off experience at the end of single limb stance and shorter step lengths of the contralateral limb. The roll-over shapes of prosthetic feet appear useful in characterization of foot function.

2021 ◽  
Author(s):  
Choolwe Muzyamba

Abstract Background The onset of the covid19 pandemic has sparked heated debate among scholars on the relevance of lockdowns. There are those in favor of the lockdown and others who are critical of it. However, despite the increased interest in understanding the relevance of lockdowns, there still has not been much focus on its relevance in low income countries like Zambia. Thus with the help of the SRT, we set out to explore and document the local characterization of the lockdown by residents of Lusaka, Zambia.Methods A qualitative study in the form of interviews was conducted in Lusaka, Zambia involving a sample of 68 participants. Due to the lockdown measures that were in place during the study, the interviews were conducted via phone calls and the data collected were later analyzed by use of thematic analysis technique.Results The lockdown was on one hand lauded for slowing down the incidence rates, preventing fatalities, and for protecting the healthcare system from collapse. On the other hand, it was criticized for exacerbating poverty levels, unemployment rates, increasing the rate of mental health problems, aiding gender based violence, and intensifying political repression and corruption. The results speak to the complexity in the characterization of the lockdown as a response to covid19 in Zambia. This observation demonstrates the folly of viewing, applying and characterizing the covid19 lockdown as a ‘one-size-fits-all’ approach in Zambia.Conclusion Thus rather than definitely establishing the lockdown as an incontestable good, as it is depicted by some scholars or as useless by its critics, our findings instead demonstrate the diversity and complexity in how it is locally viewed by Zambians. The study provides grounds for caution on simplistic and binary characterization of lockdowns. It indicates the need for careful dialog between the designers of lockdowns and citizens in order to tailor such interventions to local realities in context-specific ways. It also shows that though the development of such interventions, all the various and complex elements it embodies must be taken into account in order to realize optimum outcomes.


2017 ◽  
Vol 7 (1) ◽  
pp. 151-155 ◽  
Author(s):  
Rashid Chiposa ◽  
Rochelle H. Holm ◽  
Chimuleke Munthali ◽  
Russel C. G. Chidya ◽  
Francis L. de los Reyes

The urban areas of many low-income countries must balance a rising demand for pit latrines for household sanitation provision against limitations in space, resulting in a need for pit latrine emptying services. This study was undertaken in the peri-urban neighborhood of Area 1B in the city of Mzuzu, Malawi, to examine the characteristics of household pit latrines for designing and selecting pit latrine emptying tools. We used 150 structured household surveys and field observations. From this, a subset was selected and 30 manual cone penetrometer tests were conducted at full latrines. Chemical oxygen demand analysis was also performed for 14 pit latrines. The results indicated that in addition to serving as a disposal for fecal matter, 90% of households also used pit latrines for domestic waste. Only 10% of the studied pit latrines were lined. The filling rate in the study area is calculated to be about three years, and no respondents reported previous emptying. It is suggested pit latrine emptying technology development focuses on a maximum tool diameter of 10 cm to fit through the keyhole (squat hole) and height of 146 cm to fit inside the superstructure, as well as supporting unlined pits and the ability to pump trash.


2003 ◽  
Vol 27 (2) ◽  
pp. 89-99 ◽  
Author(s):  
A. H. Hansen ◽  
M. R. Meier ◽  
M. Sam ◽  
D. S. Childress ◽  
M. L. Edwards

The authors examined the rollover shape alignment hypothesis, which states that prosthetic feet are aligned by matching their rollover shapes with an “ideal” shape. The “ideal” shape was considered to be the rollover shape of the ablebodied footankle system. An alignment algorithm and computational alignment system were developed to set transtibial alignments based on this hypothesis. Three prosthetic feet with considerably different rollover shapes were either aligned using the alignment system or not aligned (i.e. used previous foot's alignment), and then were aligned by a team of prosthetists. No significant differences were found between rollover shapes aligned by the computational alignment system and those based on standard clinical techniques (p = 0.944). Significant differences were found between the “no alignment” shapes and the prosthetist alignment shapes (p = 0.006), and between the “no alignment” shapes and the computational alignment system shapes (p = 0.024). The results of the experiment support the hypothesis that the goal of alignment is to match the prosthetic foot's rollover shape, as closely as possible, with an “ideal” shape. The hypothesis is also supported by its ability to explain the results of previous studies. Using an “ideal” rollover shape or surface as a goal for prosthetic alignment could lead to a priori alignment, eliminating the need for alignment hardware in some cases. Being able to build the alignment into a prosthesis without special hardware could be beneficial in lowincome countries and in the fabrication of lightweight prostheses for the elderly.


2021 ◽  
Vol 22 ◽  
Author(s):  
E. Bhargav ◽  
Y. Padmanabha Reddy ◽  
K.B. Koteshwara

Abstract : Malaria, a protozoan disease led to numerous deaths and several new million cases raised due to the development of resistance as per the WHO malaria report 2019. This can be overcome by the development of an effective targeted plant-based delivery system through phytosomes that are effective in permeation and bioavailability to treat infected RBCs (parasitic cells). This review article explained the development of targeted Nanophytosomes to overcome resistance, to improve efficacy. This review paper also emphasized various quality-driven developmental approaches in developing an antimalarial product at a reasonable cost. By implementing molecular modeling techniques in development, a significant phytoconstituent with the capability of acting at the target (receptor or enzymes) of the parasite and the one with the capability to overcome drug resistance against resistant strains of parasites can be identified. Absorption Distribution Metabolism Excretion and Toxicity (ADMET) studies information provide a route to the design and formulation of a potent antimalarial agent. Efficient targeted Nanophytosomal formulations can be formulated by functionalizing or conjugating with suitable targets to direct the phytoconstituent to the infected RBCs thereby achieving complete parasitic eradication. Artificial Neural Network technology (ANN), Quality by Design (QbD), molecular dynamics, and simulation studies implementation improves quality and reduces the cost of the product, as these malarial products are much utilized in low-income countries. Hence it can be concluded that targeted developmental quality-driven approaches implementation is essential for effective malarial treatment.


2004 ◽  
Vol 20 (4) ◽  
pp. 294-306 ◽  
Author(s):  
Michel Sam ◽  
Dudley Childress ◽  
Andrew Hansen ◽  
Margrit Meier ◽  
Sophie Lambla ◽  
...  

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Nicholas P. Fey ◽  
Glenn K. Klute ◽  
Richard R. Neptune

Unilateral below-knee amputees develop abnormal gait characteristics that include bilateral asymmetries and an elevated metabolic cost relative to non-amputees. In addition, long-term prosthesis use has been linked to an increased prevalence of joint pain and osteoarthritis in the intact leg knee. To improve amputee mobility, prosthetic feet that utilize elastic energy storage and return (ESAR) have been designed, which perform important biomechanical functions such as providing body support and forward propulsion. However, the prescription of appropriate design characteristics (e.g., stiffness) is not well-defined since its influence on foot function and important in vivo biomechanical quantities such as metabolic cost and joint loading remain unclear. The design of feet that improve these quantities could provide considerable advancements in amputee care. Therefore, the purpose of this study was to couple design optimization with dynamic simulations of amputee walking to identify the optimal foot stiffness that minimizes metabolic cost and intact knee joint loading. A musculoskeletal model and distributed stiffness ESAR prosthetic foot model were developed to generate muscle-actuated forward dynamics simulations of amputee walking. Dynamic optimization was used to solve for the optimal muscle excitation patterns and foot stiffness profile that produced simulations that tracked experimental amputee walking data while minimizing metabolic cost and intact leg internal knee contact forces. Muscle and foot function were evaluated by calculating their contributions to the important walking subtasks of body support, forward propulsion and leg swing. The analyses showed that altering a nominal prosthetic foot stiffness distribution by stiffening the toe and mid-foot while making the ankle and heel less stiff improved ESAR foot performance by offloading the intact knee during early to mid-stance of the intact leg and reducing metabolic cost. The optimal design also provided moderate braking and body support during the first half of residual leg stance, while increasing the prosthesis contributions to forward propulsion and body support during the second half of residual leg stance. Future work will be directed at experimentally validating these results, which have important implications for future designs of prosthetic feet that could significantly improve amputee care.


2020 ◽  
Author(s):  
Choolwe Mphanza Muzyamba

Abstract Background The onset of the covid19 pandemic has sparked heated debate among scholars on the relevance of lockdowns. There are those in favor of the lockdown and others who are critical of it. However, despite the increased interest in understanding the relevance of lockdowns, there still has not been much focus on its relevance in low income countries like Zambia. Thus with the help of the SRT, we set out to explore and document the local characterization of the lockdown by residents of Lusaka, Zambia.Methods A qualitative study in the form of interviews was conducted in Lusaka, Zambia involving a sample of 68 participants. Due to the lockdown measures that were in place during the study, the interviews were conducted via phone calls and the data collected were later analyzed by use of thematic analysis technique. Results The lockdown was on one hand lauded for slowing down the incidence rates, preventing fatalities, and for protecting the healthcare system from collapse. On the other hand, it was criticized for exacerbating poverty levels, unemployment rates, increasing the rate of mental health problems, aiding gender based violence, and intensifying political repression and corruption. The results speak to the complexity in the characterization of the lockdown as a response to covid19 in Zambia. This observation demonstrates the folly of viewing, applying and characterizing the covid19 lockdown as a ‘one-size-fits-all’ approach in Zambia.Conclusion Thus rather than definitely establishing the lockdown as an incontestable good, as it is depicted by some scholars or as useless by its critics, our findings instead demonstrate the diversity and complexity in how it is locally viewed by Zambians. The study provides grounds for caution on simplistic and binary characterization of lockdowns. It indicates the need for careful dialog between the designers of lockdowns and citizens in order to tailor such interventions to local realities in context-specific ways. It also shows that though the development of such interventions, all the various and complex elements it embodies must be taken into account in order to realize optimum outcomes.


Author(s):  
Giovanni Andrea Cornia

This chapter presents empirical data on long-term trends in growth and income inequalitybefore discussing the nature, main features, and immediate and underlying determinants of long-term growth. It reviews the origins of income differences among world citizens by making reference to colonial history, pre-existing feudal institutions in low-income countries, and differences in growth rates between developed and developing countries. It subsequently presents the long-term growth models developed for the industrialized countries, including the Harrod–Domar model, the neoclassical exogenous growth models of Solow and Mankiw–Romer–Weil, the endogenous growth models of Romer and Aghion–Howitt, and the Unified Growth Theory. It provides also a brief comparison of the main features and dynamic properties of each model.


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