Rotavirus diarrhea – An analysis through epidemic modeling

Modelling an infectious disease like diarrhea improves the understanding of the transmission and helps in preventing it. Based on the pathogenesis, this research creates a continuous mathematical model for diarrhea (forming an SIRS system) caused by the virus rotavirus. Basic calculations including the basic reproduction number (R0) and disease-free state are successfully completed for the described system. Results show that if the basic reproduction number is kept below 1 (i.e. R0 < 1), there will be no epidemic. This mathematical model has been simulated using assumed values of parameters to test its fidelity. In order to establish the model in a functioning form, the Routh Hurwitz method has been used for the stability analysis. Model fidelity has been made stronger by conducting the sensitivity analysis and parameter estimation too. This model is very useful and has been integrated to form utilizable systems which function as a predictive system to assist in prevention of further infections of rotavirus causing diarrhea.

Decision-making in advanced heart failure patients requiring LVAD insertion: Can preoperative simulation become the way forward? A case study

Clinical practice heavily relies on results from randomized controlled trials, which may not reflect completely individual patients. Patient-specific modelling has received increasing attention in recent years. Although still far from clinical application on a daily basis, the potential of this approach is significant. The treatment of advanced heart failure may benefit from a modelling framework to guide device treatment and predict outcome. The role of mechanical circulatory support as a long-term solution is increasing in view of the evolving technology and worsening heart failure patient population. Therefore, a preoperative strategy with the ability to predict the course of events in a simulation setting may be justified. Here we present a heart failure patient discussed at a multidisciplinary team meeting whose outcome was compared with simulations carried out with CARDIOSIM$^{©}$ software to investigate the role of this approach as a planning strategy to guide intervention and predict outcome. The clinical decision process is complex and many factors are involved. Patient-specific modelling may have a role to play as part of a preoperative planning strategy with more quantitative evaluation to smooth decision-making.

A novel strain sensor using a microchannel embedded in PDMS

A novel, inexpensive, and easy-to-use strain sensor using polydimethylsiloxane (PDMS) was developed. The sensor consists of a microchannel that is partially filled with a coloured liquid and embedded in a piece of PDMS. A finite element model was developed to optimize the geometry of the microchannel to achieve higher sensitivity. The highest gauge factor that was measured experimentally was 41. The gauge factor was affected by the microchannel’s square cross-sectional area, the number of basic units in the microchannel, and the inlet and outlet configuration. As a case study, the developed strain sensors were used to measure the rotation angle of the wrist and finger joints.

In people and pets in Grenada -- do owners practice alternative and traditional medicine on both people and pets?

Introduction：Alternative and traditional medicine has been used in various cultures across the world for hundreds of years. Many regions of the world, including the Caribbean Islands, use traditional medicine practices such as charcoal for poisoning, seeds for deworming, salt for lesions, spices and herbs for inflammation, and engine oil for mange. In communities where biomedical resources are limited, alternative medicine is more cost effective and attainable for both people and their pets. Although conventional medical practices have a scientific basis, its options are often limited and such practices and treatments have physiological side effects that must be considered.Objective: The objective of this study is to identify whether people in Grenada practice traditional medicine, and if these practitioners are also implementing similar practices on their companion animals. It is hypothesized that many citizens of Grenada prefer the use of traditional medicine over conventional medicine for both themselves and their pets.Methods: In order to test this hypothesis, we conducted a cross sectional study using a questionnaire to collect data from pet owners and determine whether they practice traditional medicine – and if so, identify which specific practices were used and how they were being implemented (strictly on themselves, only on their pets, or both).Results: We found that many people use alternative medicine practices on themselves and both themselves and their pets, but few use them on just their pets.Conclusions: This study can offer us a more comprehensive understanding of alternative medicine, thereby allow us to engage pet owners in this area of healthcare. Veterinarians can be better informed of the alternative medical practices that their clients may be utilizing, which will allow them to educate the owners by offering their guidance and expertise in approaching traditional medical practices – and perhaps offer alternative medical solutions when appropriate. Furthermore, it will allow veterinarians to formulate more comprehensive patient histories in veterinary clinics around Grenada.

Phase plane quantification of single-joint smoothness

We report a metric of single joint movement smoothness based on phase plane analysis of trajectories of the wrist about the elbow. Overall smoothness was quantified as the Phase Area Ratio (PAR), comparing the total area circumscribed by the acceleration-velocity (A-V) curve, to the area of its convex hull; PAR ranges from 0 (perfectly smooth) to 1 (gross motor impairment). Elbow flexion records obtained from a cohort study showed that PAR was significantly different in intact (PAR = 9.4x10-4 ± 6.6x10-4, group average, N = 18) versus chronic stroke patients (0.11 ± 0.15, N = 9; Wilcoxon rank-sum on group means: P < .0001). Separate simulations showed that PAR was appropriately insensitive to velocity asymmetry and to scale factors, e.g. range of motion, peak- and average velocity, and movement duration. We conclude that PAR is an attractive smoothness measure, as it accomplishes four objectives: 1) insensitivity to scale factors unrelated to trajectory shape, 2) discrimination of an intact versus impaired cohort, 3) reporting a near-zero impairment for healthy actors, responding appropriately to asymmetries commonly observed in human movement, and 4) operation on a fixed, closed scale.

Knee kinematic curve representation and application to knee pathology classification

This study investigates a variational method to determine the most representative shape of a set of knee kinematic curves with application to knee pathology classification. Although they provide essential information for pathology classification, knee kinematic curves are characterized by high intra-class variability and outliers are often present. As a result, a set of several measurement curves are acquired of any single individual which are then averaged before their use for pathology classification. Rather than using the average of an individual’s recorded measurement curves, this method determines a better representative curve by first correcting the data to account for outliers occurrence and class variability using a variational method. The correction is performed by simultaneous minimization of a set of objective functions, one for each curve in the measurement set, and consisting of a weighed sum of two terms: a data term of conformity of the corrected curve to the given curve, and a regularization term of proximity of the corrected curve to the mean of all the corrected curves to inhibit the influence of outliers in the set. Validation tests were performed to discriminate between knee osteoarthritis data (OA) and non-OA data. Using a support vector machine, the classification accuracy with the proposed representation was 86%, with 81% sensitivity and 90% specificity, compared to 83% accuracy for the standard representation by average, with 76% sensitivity and 90% specificity. The representation has also been tested within the OA category to distinguish the femero-tibial patholgy from the femero-patellar, giving 76% accuracy, with 76% sensitivity and 76% specificity, compared to 69% accuracy, with 62% sensitivity and 76% specificity. These significant improvements by the proposed method warrant its further investigation by application to other biomedical engineering pattern classification problems and datasets.

Laser Doppler Flowmetry versatile acquisition system with low quantization error

The Laser Doppler Flowmetry (LDF) is a non-invasive technique used to evaluate blood perfusion of various human tissues like the skin or the fundus of the eye. It is based on the scattering of light on moving red blood cells in tissue. Frequency shifted scattered light is detected and provide an electrical signal. Physical models for LDF use the DC and AC components of this signal. If AC is small relative to the DC, digitalization becomes an issue, and if more than two LDF signal acquisitions and analysis have to be done simultaneously, the device becomes expensive and bulky. We propose here a versatile and inexpensive acquisition system, which overcomes quantization errors issue by first separating DC from AC, then amplifying AC and finally recombining both signals before digitalization. We designed an analog circuit combined with a 12 bit analog-to-digital converter, a microcontroller unit and a Raspberry Pi2 (Rpi2) for the signal processing. Results are accessed remotely from the Rpi2 through HTTP protocol. Multiple systems can easily be used simultaneously for multichannel acquisitions.

Identification of emphysema patterns in high resolution computed tomography images

Fractal dimension (FD) is a very useful metric for the analysis of image structures with statistically self-similar properties. It has applications in areas such as texture segmentation, shape classification and analysis of medical images. Several approaches can be used for calculating the fractal dimension of digital images; the most popular method is the box-counting method. It is also very challenging and difficult to classify patterns in high resolution computed tomography images (HRCT) using this important descriptor. This paper applied the Holder exponent computation of the local intensity values for detecting the emphysema patterns in HRCT images. The absolute differences between the normal and the abnormal regions in the images are the key for a successful classification of emphysema patterns using the statistical analysis. The results obtained in this paper demonstrated the effectiveness of the predictive power of the features extracted from the Holder exponent in the analysis and classification of HRCT images. The overall classification accuracy achieved in lung tissue layers is greater than 90%, which is an evidence to prove the effectiveness of the methods investigated in this paper.

Correspondence between waist-to-height ratio and body mass index in juniors

Despite the increase in body mass through childhood and adolescence is countered by the increase in height in the Body Mass Index (BMI), this measure is inadequate for judging the degree of excess weight among the young. Unlike using clearly defined cut points, same for any stage of adulthood, it is required to consult BMI-for-age charts, which can be a demanding exercise when data analysis is involved. The waist circumference to height ratio (WCHR) was hypothesised to be invariant to age change, and this is generally supported by the epidemiological evidence. This paper analyses a sample of NHANES data to find a connection between BMI, WCHR and Age. A strong linearity between the anthropometric measures is demonstrated, thus enabling estimation of WCHR for a given BMI and Age. The pattern of change of this parameter at BMI levels that indicate the transition to overweight state or obesity thus becomes unravelled. The results strongly support the feasibility of a universal WCHR threshold for the overweight state past early childhood and through adolescence, and the estimated one is similar to the WCHR levels found elsewhere in the literature.

Automatic bone drilling using a novel robot in orthopedic trauma surgery

Background: Currently, applications of robotized systems in orthopedic trauma surgery steadily increase due to their functional abilities facilitating surgeon skills. The aim of this study is to present the functional advantages of a recently developed robot for bone drilling.Methods: Ex-vivo experiments were performed on fresh porcine and bovine bones, as well as on fresh and embalmed human bones such as femora, vertebrae and rips, by the use of the robot for bone drilling to identify diverse control parameters and analyse thrust force and drill bit temperature during drilling.Results: Experimental data during drilling is shown, control algorithms are described and bone drilling modes are characterized. Maximal values of thrust force and temperature are detected. Controlling thrust force seems to be the proper way to reduce force resistance and hence temperature during drilling. In automatic drilling mode, preliminary defined channel depth is drilled with accuracy of 0.1 mm, and far cortex end recognition is proved to work reliably for automatic stop with minimal controlled soft tissue penetration. Cortex and bone marrow thickness are measured and analysed in real time.Conclusion: The bone drilling robot is programmed to follow with high accuracy parameters defined by the surgeon. Enhancing surgeon’s freedom and responsibility to make decisions, it can perform precise manipulations, decreasing the influence of subjective factors and increasing patient’s safety.