Medical devices & sensors最新文献

This work presents a clinical study of a chest-based blood pressure (BP) monitoring technique. This research was designed to examine pulse transit time (PTT) and to measure beat-to-beat and cuff-based systolic BP (SBP) and diastolic BP (DBP). The PTT values were extracted as the time difference between the end of the pre-ejection period (PEP) measured using an on-body continuous-wave radar (CWR) sensor and the pulse arrival time (PAT) in central arteries extracted from the shoulders' bio-impedance (BImp) signal. The system was investigated under three experimental conditions: (a) resting at various postures; (b) rising exercise stress, followed by resting; and (c) spraying inconstant doses of glyceryl trinitrate (GTN) medicine and recovery. Data were collected from 43 volunteers who participated in posture recordings, 26 undertook exercises and 17 experienced GTN spray. The BImp-based PTT was compared with PPG-based one (peripheral) in terms of BP estimation. Various mathematical methods of calculating BPs from PTTs were investigated to gain the most accurate outcomes. We demonstrate the accuracy of each model in this work. Our study found that cuffless BP determined from PTT derived from central arteries shows more than 3% accuracy compared to that determined from peripheral arteries.

The role of electrical stimuli in directing cellular activities during natural tissue healing and regeneration process has been well recognized. This observation has prompted the development and use of exogenous electrical stimulations in the treatment of delayed unions and non-unions of bone fracture in different parts of the human skeletal system. Considerable amount of clinical evidences has also been generated on the benefits of exogenous bone growth stimulators. However, the clinical efficacy and safety of these exogenous electrical stimulating methods are being argued to be inconsistent and inconclusive, due to lack of sufficient number of well-controlled, randomized clinical studies. As a result, there has been significant interest in the development of smart biomaterials, which can generate in situ electrical stimuli, for accelerated bone repair, healing and regeneration. These smart biomaterials are essentially either composite biomaterials containing electrically active materials or biomaterials that can be polarized. The primary objective of this mini review was to provide an overview of different exogenous electrical stimulation methods and biocomposites for in situ stimulation, which can be used for bone growth and healing. The first part is focused on exogenous stimulation methods, and the second part discusses the use of biocomposites containing electrically active materials such as piezoelectric materials and multiferroic materials for accelerated repair and regeneration of bone.

Sepsis is a potentially fatal physiological state caused by an imbalance in the body's immune response to an infection and is one of the most common causes for deaths in the non-coronary intensive care unit worldwide. In this article, the state of art on sepsis is presented in a manner that facilitates easy comprehension also for the non-medical researchers by introducing sepsis, its causes, extent and comparison of diagnostic techniques (conventional labeled as well as label-free detection). The article also provides a comprehensive discussion on sepsis biomarkers, to help researchers from multi-disciplinary domain in developing devices and ideas to complement the existing sepsis diagnosis systems for quick and premature detection of the physiological condition and reduce mortality by means of early treatments.

In vivo monitoring of biomedical implants to detect early stages of failure is currently unavailable. State-of-the-art imaging techniques do not provide information about small-scale localized changes in the implant and surrounding environment, which are key to early detection of failure. Here, we discuss different electrochemical responses of implants during degradation which may be utilized to develop biosensors to monitor implant degradation in vivo. This review is focused on identifying the need, potential measurement techniques and degradation response obtained from sensors based on electrochemical signature of biomedical implants. Benefits of designing these novel sensors include continuous monitoring, early failure detection, reduced post-surgery and prevention of catastrophic failure from implant degradation.

Glaucoma is a chronic eye disease where an increase in intraocular pressure (IOP) permanently damaging the optic nerve leading to irreversible vision loss. Intraocular pressure is the main factor for monitoring the progression of glaucoma and has been found to fluctuate throughout the day. A continuous monitoring system can track the fluctuations in the intraocular pressure throughout the day, improving the management of the disease. A novel non-invasive wearable sensor was created to monitor the fluctuating corneal curvature of the eye and directly relate the deformation to the intraocular pressure. The wearable sensor was able to capture on average 40.8 µm/mmHg with a standard deviation of 29.4 in fluid location per increase in intraocular pressure with an ability to return over 80% back to its original position indicating a good ability to accurately track the fluctuations in the IOP.

The main purpose of this study is to present a systematically assessment of wear characteristics of hybrid dental composites. Lanthanum oxide (La₂O₃) nanofillers are an imperative part of fillers in hybrid dental composites to increase their cosmetic features and radiopacity that are added as a second filler along with quartz microfillers. In this research, hybrid nanocomposite samples are synthesized by different content of La₂O₃ nanofillers to study their effect on surface behaviour, friction coefficient and wear resistance that further discussed using scanning electron microscopy (SEM) images of the wear track and debris. The results provide a significant influence of nanofillers on wear resistance with samples having higher nanofillers showing lower wear resistance; however, coefficient of friction reaches an optimum and increase with higher content. The wear behaviour is also related to micro-hardness of specimens to find a detailed understanding of wear mechanism.