Low delay rate adaptive pacemaker using FPGA embedded piezoelectric sensor

Abstract

This paper presents the hardware implementation of low delay, power-efficient, rate-adaptive dual-chamber pacemaker (RDPM) using a piezoelectric sensor. Rate adaptive pacemaker has the ability to sense the patient’s activity by means of some special sensors and it controls the pacing rate according to the patient’s activity. Ideally, there should be no delay between sensing and the subsequent pacing operation performed by the pacemaker. However, delay in the responses of various components in the circuitry produces an accumulative delay effect in any practical circuit. Physical activity and the physiological needs of the patient can be easily adapted by the rate-responsive pacemakers using a wide range of sensor information. The piezo-electric sensor recognises the pressure on human muscles because of physical activity and converts it to an electrical signal, which is received by the pulse generator of the pacemaker. When the patient is in the rest mode, the heart rate is the only parameter that is to be detected by the pacemaker. Thus, the heart rate and the physical activity both are the inevitable parameters for the design of RDPM. Performance analysis of the proposed RDPM shows a significant reduction in the delay between sensing and pacing. Device utility analysis shows that the proposed design not only requires lesser memory but also reduces the number of components on the chip. Therefore, it becomes very clear that the proposed pacemaker design will consume much lesser power.     

Performance status and comorbidity predict transplant-related mortality after allogeneic hematopoietic cell transplantation.

Comorbidity measurements have recently been used to improve estimation of tolerance to allogeneic hematopoietic cell transplantation (HCT). We sought to determine the independent effect of comorbidity and performance status on HCT outcome and to devise a simple risk classification system for transplant-related mortality. We analyzed 105 consecutively enrolled patients who underwent HCT and received reduced intensity conditioning with fludarabine, melphalan, and alemtuzumab. Comorbid conditions were tabulated using 2 scales, the Charlson Comorbidity Index (CCI) and the Kaplan-Feinstein Scale (KFS). Comorbid conditions were found in 47% of patients by the KFS and in 27% by the CCI (P < .001). Using the Eastern Cooperative Oncology Group Performance Status (PS) scale, 34% had a PS score >0 (range, 0-2). A simple scale combining the KFS and PS enabled separation of high- from low-risk patients, with 6-month cumulative incidences 50% and 15%, respectively for transplant-related mortality (P = .001) and enhanced prognostic power over the CCI alone (P = .018). Prospective studies evaluating more comprehensive functional and comorbidity measurements are warranted.     

Screening for cognitive impairment in older adults attending an eye clinic

PURPOSE: We conducted a cross-sectional study examining potentially modifiable factors associated with cognitive impairments (mild or severe) in older whites, African Americans and Hispanics attending an outpatient eye clinic. METHODS: In-clinic interviews and physical examinations assessed social, demographic and health information from 100 consecutive Hispanic, African-American and white adults aged > or = 55. Our primary outcome was presence of any cognitive impairment (mild or severe) using the St. Louis University Mental Status Examination (SLUMS) scale. RESULTS: Of the 100 subjects, 65 screened positive for cognitive impairments on the SLUMS cognitive instrument: 46 with mild cognitive impairment and 19 with severe impairment (possible dementia). African-American and Hispanic adults (nonwhites) were significantly more likely to have cognitive impairment compared to white adults (OR 2.80: 95% CI = 1.05-7.44), independent of age, years of education and systolic blood pressure. Subjects with diabetes also had increased odds of cognitive impairments (OR 3.28, 95% CI = 1.21-8.90) even after adjusting for relevant confounders. There was a nonsignificant trend between visual acuity impairment and cognitive impairment (p = 0.059). CONCLUSIONS: Sixty-five percent of adults aged > or = 55 attending the eye clinic screened positive for cognitive impairments, with higher rates among nonwhites and adults living with diabetes.     

Necrotising Fasciitis of the Neck and Anterior Chest Wall

Maxillary antral mucocoeles have an incidence of only 3–10%. Mucocoeles are more commonly seen in the frontoethmoidal region. We present one such rare case of a 52-year-old lady who came to us with complaints of pain and swelling of the left cheek of 4 months duration. Clinical examination and investigation revealed a giant maxillary sinus mucocoele which was duly treated surgically. We discuss its classical presentation and management since such large mucocoeles are not often seen in the maxillary sinus.     

Alternatives to animal testing: A review

The number of animals used in research has increased with the advancement of research and development in medical technology. Every year, millions of experimental animals are used all over the world. The pain, distress and death experienced by the animals during scientific experiments have been a debating issue for a long time. Besides the major concern of ethics, there are few more disadvantages of animal experimentation like requirement of skilled manpower, time consuming protocols and high cost. Various alternatives to animal testing were proposed to overcome the drawbacks associated with animal experiments and avoid the unethical procedures. A strategy of 3 Rs (i.e. reduction, refinement and replacement) is being applied for laboratory use of animals. Different methods and alternative organisms are applied to implement this strategy. These methods provide an alternative means for the drug and chemical testing, up to some levels. A brief account of these alternatives and advantages associated is discussed in this review with examples. An integrated application of these approaches would give an insight into minimum use of animals in scientific experiments.