A Musculoskeletal Model Customized for Sagittal and Frontal Knee Kinematics With Improved Knee Joint Stability.

Current lower limb musculoskeletal (MSK) models focus on sagittal plane kinematics. However, abnormal gait is typically associated with sagittal plane motions crossing into other planes, limiting the use of current MSK models. The purpose of this study was twofold, first, to extend the capability of a full-body MSK model from the literature to include frontal knee plane kinematics during healthy gait, and second, to propose and implement a realistic muscle discretization technique. Two MSK model constructs were derived-the first construct (Knee2_SM) allowed two degrees-of-freedom (sagittal and coronal) at the knee and the second construct (Knee2_MM) implemented multiline elements for all the lower limb muscles in conjunction with two knee degrees-of-freedom. Motion analysis data of normal gait cycle from 10 healthy adults were used to compare joint kinematics, muscle moment arms, muscle forces, and muscle activations, between new constructs and the original model. Knee varus-valgus trajectories were estimated with the mean peak values ranging from 9.49 deg valgus to 1.57 deg varus. Knee2_MM predicted a significant difference (p < 0.05) in moment arms and forces in those muscles responsible for medial-lateral stability of the knee. The simulated muscle activations generated by the Knee2_MM model matched more closely to the experimental electromyography (EMG) when qualitatively compared. This study enhances the capability of the sagittal plane full-body MSK model to incorporate knee varus-valgus motion while keeping the joint stability intact and improving muscle prediction.

An FPGA-based design for power efficient low delay rate adaptive pacemaker using accelerometer and heart rate sensor.

This paper presents a power efficient, low delay and rate adaptive dual chamber pacemaker (PLRDPM) using heart rate and accelerometer sensor. In recent years, number of modifications have been done in the pacemaker design. However, design of an implantable device on an open source is still challenging. Through this paper, we are proposing a "proof of concept" for the design of PLRDPM on FPGA for improving the vital parameters: delay and power consumption. The proposed PLRDPM comprises of accelerometer and heart rate sensors to measure physical activity's effect on heart rate of the bradycardia patients. A rate adaptive pacing algorithm has been designed using two sensor's data, to reduce the delay and power consumption. However, delay in the responses of various components in the circuitry produces an accumulative delay effect in any practical circuit. The delay and the power consumption for the proposed PLRDPM are found to be 2.82 ns and 9 mW, respectively.

3D Printed Chitosan Composite Scaffold for Chondrocytes Differentiation.

AIMS: Our aim is to develop 3D printed chitosan-gelatin-alginate scaffolds using a costeffective in house designed 3D printer followed by its characterization. To observe chondrocyte differentiation on 3D printed scaffolds as part of scaffold application. BACKGROUND: Cartilage is considered to be a significant tissue in humans. It is present in between the rib cage, the lobe of the ear, nasal septum in the form of hyaline cartilage, in between ribs costal cartilage, intervertebral discs in the form of fibrocartilage, meniscus, larynx, epiglottis and between various joints of bones. To replace or repair damaged tissues due to disorders or trauma, thousands of surgical procedures are performed daily. 3D printing plays a crucial role in the development of controlled porous architectures of scaffolds for cartilage tissue regeneration. Advancement in 3D printing technology like inkjet, micro- extrusion in 3D bioprinting, Laser-assisted 3D Bioprinting (LAB), stereolithography combination with biomaterials plays a crucial role in the quick development of patient-specific articulating cartilage when need in a short period frame. OBJECTIVE: Our objective is to develop different compositions of chitosan-gelatin-alginate composite hydrogel scaffolds with controlled porosity and architectures with the application of 3D printing and observe the growth of cartilage on it. To achieve as proposed, an in-house 3D paste extruder printer was developed, which is capable of printing porous composite chitosan hydrogel scaffolds of desired architecture layer by layer. After the characterization of 3D printed chitosan composite scaffolds, the differentiation of chondrocyte was observed using hMSC. METHODS: In present paper process for the development of chitosan-alginate-gelatin composite hydrogel, 3D printing, morphological characterization, and observation for differentiation of chondrocytes cells on 3D printed chitosan composite hydrogels is presented. The present study is divided into three parts: in first part development of composite chitosan-alginate-gelatin hydrogel with the utilization of in house customized assembled paste extruder based 3D printer, which is capable of printing chitosan composite hydrogels. In the second part, the characterization of 3D printed chitosan composite scaffolds hydrogel is performed for evaluating the morphological, mechanical, and physical properties. The prepared composite scaffolds were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction(XRD), Scanning Electron Microscopy SEM, swelling property, mechanical testing, porosity, etc. In the last part of the study, the differentiation of chondrocytes cells was observed with human Mesenchymal Stem Cells (hMSC) on 3D printed scaffolds and showed positive results for the same. RESULTS: Stereolithography (STL) files of 3D models for porous chitosan composite were developed using Computer-Aided Design (CAD) and printed with a hydrogel flow rate within the range of 0.2-0.25 ml/min. The prepared scaffolds are highly porous, having optimum porosity, optimal mechanical strength to sustain the cartilage formation. The 3D printed chitosan composite scaffolds show supports for the differentiation of chondrocytes. The above study is helpful for in-vivo regeneration of cartilage for patients having related cartilage disorders. CONCLUSION: This method helps in regeneration of degenerated cartilage for patient-specific and form above experiment we also concluded that 3D printed chitosan scaffold is best suited for the regeneration of chondrocyte cells.

Scalp electroencephalography (sEEG) based advanced prediction of epileptic seizure time and identification of epileptogenic region.

Objectives Epilepsy is characterized by uncontrollable seizure during which consciousness of patient is disturbed. Prediction of the seizure in advance will increase the remedial possibilities for the patients suffering from epilepsy. An automated system for seizure prediction is important for seizure enactment, prevention of sudden unexpected deaths and to avoid seizure related injuries. Methods This paper proposes the prediction of an upcoming seizure by analyzing the 23 channel non-stationary EEG signal. EEG signal is divided into smaller segments to change it into quasi-stationary data using an overlapping moving window. Brain region is marked into four regions namely left hemisphere, right hemisphere, central region and temporal region to identify the epileptogenic region. The epileptogenic region shows significant variations during pre-ictal state in comparison to the other regions. So, seizure prediction is carried out by analyzing EEG signals from this region. Seizure prediction is proposed using features extracted from both time and frequency domain. Relative entropy and relative energy are extracted from wavelet transform and Pearson correlation coefficient is obtained from time domain EEG signal. Extracted features have been smoothened using moving average filter. First order derivative of relative features have been used to normalize the intervariability before deciding the threshold for marking the prediction of seizure. Results Isolated seizures where pre-ictal duration of more than 1 h is reported has been detected with an accuracy of 92.18% with precursory warning 18 min in advance and seizure confirmation 12 min in advance. An overall accuracy of 83.33% with false positive alarm rate of 0.01/h has been obtained for all seizure cases with average prediction time of 9.9 min.

The implications of recent advances in carboxymethyl chitosan based targeted drug delivery and tissue engineering applications.

Over the last decade carboxymethyl chitosan (CMCS) has emerged as a promising biopolymer for the development of new drug delivery systems and improved scaffolds along with other tissue engineering devices for regenerative medicine that is currently one of the most rapidly growing fields in the life sciences. CMCS is amphiprotic ether, derived from chitosan, exhibiting enhanced aqueous solubility, excellent biocompatibility, controllable biodegradability, osteogenesis ability and numerous other outstanding physicochemical and biological properties. More strikingly, it can load hydrophobic drugs and displays strong bioactivity which highlight its suitability and extensive usage for preparing different drug delivery and tissue engineering formulations respectively. This review provides a comprehensive introduction to various types of CMCS based formulations for delivery of therapeutic agents and tissue regeneration and further describes their preparation procedures and applications in different tissues/organs. Detailed information of CMCS based nano/micro systems for targeted delivery of drugs with emphasis on cancer specific and organ specific drug delivery have been described. Further, we have discussed various CMCS based tissue engineering biomaterials along with their preparation procedures and applications in different tissues/organs. The article then, gives a brief account of therapy combining drug delivery and tissue engineering. Finally, identification of major challenges and opportunities for current and ongoing application of CMCS based systems in the field are summarised.

Biomedical applications of carboxymethyl chitosans.

This review outlines the recent developments on carboxymethyl chitosan-based bio-medical applications. Carboxymethyl chitosan, a water soluble derivative of chitosan, with enhanced biological and physicochemical properties compared to chitosan, has emerged as a promising candidate for different biomedical applications. Introducing small chemical groups like carboxymethyl to the chitosan structure can drastically increase the solubility of chitosan at neutral and alkaline pH values without affecting their characteristic properties. Due to improved biocompatibility, high moisture retention ability more viscosity and enhanced antimicrobial property of carboxymethyl chitosan than chitosan makes it promising candidate for hydrogels and wound healing applications. The biodegradability and biocompatibility of carboxymethyl chitosan has significant interest with application as biomaterial for tissue engineering. Apart from this, the easy of carboxymethyl chitosan can be easily processed into nanoparticles so it has shown promise for drug delivery, bioimaging, biosensors and gene therapy applications. The contribution of carboxymethyl chitosan to green chemistry in the recent years has also been given in detail. This review will focus on preparative methods and physicochemical and biological properties of carboxymethyl chitosan with particular emphasis on biomedical and pharmaceutical applications of this derivative of chitosan.