Investigation of pulse oximeter failure rates during artificial hypoperfusion utilising a custom made multimode pulse oximetery sensor

Pulse oximetry utilises the technique of photople-thysmography (PPG) to estimate arterial oxygen saturation values (SpO2). In poorly perfused tissues, SpO2 readings may be compromised due to the poor quality of the PPG signals. In order to investigate further the threshold where pulse oximetry fails to produce accurate SpO2 values, we have developed a custom made multimode finger pulse oximetry probe that operates in conventional, reflectance and transmittance mode independently and also in a combined mode called transreflectance. Experiments on twenty healthy volunteers undergoing induced artificial hypoperfusion utilising a brachial blood pressure cuff were performed in order to investigate the possible threshold of failure to accurately estimate SpO2 values from all pulse oximetry modes. The results suggest that the transreflectance pulse oximeter endures more in estimating accurately SpO2 values when compared with the other two custom made pulse oximeters and a commercial finger pulse oximeter

Water-pipe smoking and albuminuria: new dog with old tricks

Water-pipe (WP) smoking is on rise worldwide for the past few years, particularly among younger individuals. Growing evidence indicates that WP smoking is as harmful as cigarette smoking. To date, most of the research has focused on acute health effects of WP smoking, and evidence remains limited when it comes to chronic health effects in relation to long-term WP smoking. Therefore, the aim of this study was to examine the association between WP smoking and albuminuria in apparently healthy individuals. This analysis was conducted on data of a population-based cross-sectional study—the Urban Rural Chronic Diseases Study (URCDS). The study sample was recruited from three sites in Pakistan. Trained nurses carried out individual interviews and obtained the information on demographics, lifestyle factors, and past and current medical history. Measurements of complete blood count, lipid profile, fasting glucose level, and 24-hour albuminuria were also made by using blood and urine samples. Albumin excretion was classified into three categories using standard cut-offs: normal excretion, high-normal excretion and microalbuminuria. Multiple logistic regression models were used to examine the relationship between WP smoking and albuminuria. The final analysis included data from 1,626 health individuals, of which 829 (51.0%) were males and 797 (49.0%) females. Of 1,626 individuals, 267 (16.4%) were current WP smokers and 1,359 (83.6%) were non-WP smokers. WP smoking was significantly associated with high-normal albuminuria (OR = 2.33, 95% CI 1.68-3.22, p-value <0.001) and microalbuminuria (OR = 1.75, 95% CI 1.18-2.58, p-value 0.005) after adjustment for age, sex, BMI, social class, hypertension, and diabetes mellitus. WP smoking was significantly associated with high-normal albuminuria and microalbuminuria when analysis was stratified on hypertension and diabetes mellitus categories. WP smoking has a strong association with albuminuria in apparently healthy individuals. More research is warranted to evaluate the temporality of this association between WP smoking and albuminuria

Alliance free and alliance cover sets

A \emph{defensive} (\emph{offensive}) $k$-\emph{alliance} in $\Gamma=(V,E)$ is a set $S\subseteq V$ such that every $v$ in $S$ (in the boundary of $S$) has at least $k$ more neighbors in $S$ than it has in $V\setminus S$. A set $X\subseteq V$ is \emph{defensive} (\emph{offensive}) $k$-\emph{alliance free,} if for all defensive (offensive) $k$-alliance $S$, $S\setminus X\neq\emptyset$, i.e., $X$ does not contain any defensive (offensive) $k$-alliance as a subset. A set $Y \subseteq V$ is a \emph{defensive} (\emph{offensive}) $k$-\emph{alliance cover}, if for all defensive (offensive) $k$-alliance $S$, $S\cap Y\neq\emptyset$, i.e., $Y$ contains at least one vertex from each defensive (offensive) $k$-alliance of $\Gamma$. In this paper we show several mathematical properties of defensive (offensive) $k$-alliance free sets and defensive (offensive) $k$-alliance cover sets, including tight bounds on the cardinality of defensive (offensive) $k$-alliance free (cover) sets

The modified Glasgow prognostic score in prostate cancer: results from a retrospective clinical series of 744 patients

<p>Background: As the incidence of prostate cancer continues to rise steeply, there is an increasing need to identify more accurate prognostic markers for the disease. There is some evidence that a higher modified Glasgow Prognostic Score (mGPS) may be associated with poorer survival in patients with prostate cancer but it is not known whether this is independent of other established prognostic factors. Therefore the aim of this study was to describe the relationship between mGPS and survival in patients with prostate cancer after adjustment for other prognostic factors.</p> <p>Methods: Retrospective clinical series on patients in Glasgow, Scotland, for whom data from the Scottish Cancer Registry, including Gleason score, Prostate Specific Antigen (PSA), C-reactive protein (CRP) and albumin, six months prior to or following the diagnosis, were included in this study.</p> <p>The mGPS was constructed by combining CRP and albumin. Five-year and ten-year relative survival and relative excess risk of death were estimated by mGPS categories after adjusting for age, socioeconomic circumstances, Gleason score, PSA and previous in-patient bed days.</p> <p>Results: Seven hundred and forty four prostate cancer patients were identified; of these, 497 (66.8%) died during a maximum follow up of 11.9 years. Patients with mGPS of 2 had poorest 5-year and 10-year relative survival, of 32.6% and 18.8%, respectively. Raised mGPS also had a significant association with excess risk of death at five years (mGPS 2: Relative Excess Risk = 3.57, 95% CI 2.31-5.52) and ten years (mGPS 2: Relative Excess Risk = 3.42, 95% CI 2.25-5.21) after adjusting for age, socioeconomic circumstances, Gleason score, PSA and previous in-patient bed days.</p> <p>Conclusions: The mGPS is an independent and objective prognostic indicator for survival of patients with prostate cancer. It may be useful in determining the clinical management of patients with prostate cancer in addition to established prognostic markers.</p&gt

Investigation of photoplethysmographic signals and blood oxygen saturation values on healthy volunteers during cuff-induced hypoperfusion using a multimode PPG/SpO2 sensor

Photoplethysmography (PPG) is a technique widely used to monitor volumetric blood changes induced by cardiac pulsations. Pulse oximetry uses the technique of PPG to estimate arterial oxygen saturation values (SpO2). In poorly perfused tissues, SpO2 readings may be compromised due to the poor quality of the PPG signals. A multimode finger PPG probe that operates simultaneously in reflectance, transmittance and a combined mode called “transreflectance”’ was developed, in an effort to improve the quality of the PPG signals in states of hypoperfusion. Experiments on 20 volunteers were conducted to evaluate the performance of the multimode PPG sensor and compare the results with a commercial transmittance pulse oximeter. A brachial blood pressure cuff was used to induce artificial hypoperfusion. Results showed that the amplitude of the transreflectance AC PPG signals were significantly different (p\0.05) than the AC PPG signals obtained from the other two conventional PPG sensors (reflectance and transmittance). At induced brachial pressures between 90 and 135 mmHg, the reflectance finger pulse oximeter failed 25 times (failure rate 42.2 %) to estimate SpO2 values, whereas the transmittance pulse oximeter failed 8 times (failure rate 15.5 %). The transreflectance pulse oximeter failed only 3 times (failure rate 6.8 %) and the commercial pulse oximeter failed 17 times (failure rate 29.4 %)

Selection of HyspIRI optimal band positions for the earth compositional mapping using HyTES data

The National Aeronautics and Space Administration (NASA) has proposed the launch of a new space-borne sensor called HyspIRI (Hyperspectral and Infrared Imager) which will cover the spectral range from 0.4–12 μm. Two instruments will be mounted on HyspIRI platform: 1) a hyperspectral instrument which can sense earth surface between 0.4 and 2.5 μm at 10 nm intervals and 2) a multispectral infrared sensor will acquire images between 3 and 12 μm in eight spectral bands (one in Mid infrared (MIR) and seven in Thermal Infrared (TIR)). The TIR spectral wavebands will be positioned based on their importance in various applications. This study aimed to identify HyspIRI optimal TIR wavebands position for earth compositional mapping. A Genetic Algorithm coupled with the Spectral Angle Mapper (GA-SAM) was used as a spectral bands selector. High dimensional HyTES (Hyperspectral Thermal Emission Spectrometer) emissivity spectra comprised of 202 spectral bands of Cuprite and Death Valley regions were used to select meaningful subsets of bands for earth compositional mapping. The GA-SAM was trained for fifteen mineral classes and the algorithms were run iteratively 50 times. High calibration (> 95%) and validation (> 90%) accuracies were achieved with a limited number (seven) of spectral bands selected by GA-SAM. The knowledge of important band positions will help the scientists of the HyspIRI group to place spectral bands in regions where accuracies of earth compositional mapping can be enhanced

Longevity Framework: Leveraging Online Integrated Aging-Aware Hierarchical Mapping and VF-Selection for Lifetime Reliability Optimization in Manycore Processors

Rapid device aging in the nano era threatens system lifetime reliability, posing a major intrinsic threat to system functionality. Traditional techniques to overcome the aging-induced device slowdown, such as guardbanding are static and incur performance, power, and area penalties. In a manycore processor, the system-level design abstraction offers dynamic opportunities through the control of task-to-core mappings and per-core operation frequency towards more balanced core aging profile across the chip, optimizing the system lifetime reliability while meeting the application performance requirements. This article presents Longevity Framework (LF) that leverages online integrated aging-aware hierarchical mapping and voltage frequency (VF)-selection for lifetime reliability optimization in manycore processors. The mapping exploration is hierarchical to achieve scalability. The VF-selection builds on the trade-offs involved between power, performance, and aging as the VF is scaled while leveraging the per-core DVFS capabilities. The methodology takes the chip-wide process variation into account. Extensive experimentation, comparing the proposed approach with two state-of-the-art methods, for 64-core and 256-core systems running applications from PARSEC and SPLASH-2 benchmark suites, show an improvement of up to 3.2 years in the system lifetime reliability and 4× improvement in the average core health

Impact of duration of therapy on side effect profile of anti-HCV protocol: A retrospective cohort study from two tertiary health facilities in Pakistan

Purpose: To evaluate the plausible risks and adverse effects related to the duration of therapy in hepatitis C (HCV) patients in Lahore, Pakistan.Method: A retrospective observational study involving 250 HCV patients who received combination therapy with ribavirin and interferon was conducted. The patients were segregated into two groups on the basis of duration of therapy (≤ 6 months and > 6 months). Adverse effect profiles of patients under treatment were collected using a pre-validated questionnaire and compared using Pearson’s Chi- Square Test/Chi-Square Goodness-of-Fit tests and unpaired t-test.Results: Patients who underwent treatment for ≤ 6 months frequently encountered side-effects such as GIT disturbance (23.77 %) and joint pains (29.63 %). Additionally, diabetes mellitus (27.86 %) and frequent injections (74.59 %) were the most commonly observed co-morbid condition and disease risk, respectively. On the other hand, in patients who underwent therapy for > 6 months, skin disorders (30.46 %) and gastric acidity (10.15 %) were the most frequently observed side-effects with less frequent reporting on co-morbid conditions and disease risk factors. Moreover, there was a significant reduction in body weight (p = 0.03), serum bilirubin (p = 0.0005), albumin (p = 0.003) and triglycerides (p = 0.006) levels due to longer duration of treatment.Conclusion: The data suggest that treatment-related risks are higher among HCV patients on shorter treatment duration whereas adverse events subside in patients on longer duration of therapy (>6 months). Changes in biochemical profile were also more evident in those receiving treatment for periods >6 months.Keywords: Interferon, Ribavirin, Side effects, Duration of therapy, Outcomes of therap

Investigation of finger reflectance photoplethysmography in volunteers undergoing a local sympathetic stimulation

Optical sensors used in clinical applications have gained great popularity over the last few decades, especially the photoplethysmographic (PPG) technique used in estimating arterial blood oxygen saturation in the well-known medical devices called pulse oximeters. In this study we investigate the photoplethysmogram further in an effort to understand its origin better, as there is a significant void in the current knowledge on the PPG quantitative measurement. The photoplethysmographic signal provides a heart rhythm pulsating AC component, and a non-pulsating DC component. The signal is commonly believed to originate from tissue volume changes only and hasn't been investigated intensively. This in vivo study examines the source of the PPG signal in relation to pulse amplitude and pulse rhythm while volunteers undergo a right hand ice immersion. It was found that the PPG signal is sensitive in detecting the sympathetic stimulation which corresponds to volumetric and heart rate changes. During the immersion, AC pulse amplitudes (PA) from both hands decreased significantly, while DC levels increased significantly in the right hand and non-significantly in the left hand. Also, a significant decrease in the pulse repetition time (PRT) was observed. Using blood pressure-flow theories, these results suggest that there are possibly other factors in the blood flow regulation that alter the blood optical density which contributes to the detected signal. Further studies need to investigate PPGs in relation to blood optical density and the dynamics of the pulsatile flow effects besides volumetric changes. Such investigations might explore further applications of the PPG in medicine