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2.
Opt Lett ; 42(2): 203-206, 2017 Jan 15.
Article in English | MEDLINE | ID: mdl-28081076

ABSTRACT

We report a photothermal modulation of Mie scattering (PMMS) method that enables concurrent spatial and spectral discrimination of individual micron-sized particles. This approach provides a direct measurement of the "fingerprint" infrared absorption spectrum with the spatial resolution of visible light. Trace quantities (tens of picograms) of material were deposited onto an infrared-transparent substrate and simultaneously illuminated by a wavelength-tunable intensity-modulated quantum cascade pump laser and a continuous-wave 532 nm probe laser. Absorption of the pump laser by the particles results in direct modulation of the scatter field of the probe laser. The probe light scattered from the interrogated region is imaged onto a visible camera, enabling simultaneous probing of spatially-separated individual particles. By tuning the wavelength of the pump laser, the IR absorption spectrum is obtained. Using this approach, we measured the infrared absorption spectra of individual 3 µm PMMA and silica spheres. Experimental PMMS signal amplitudes agree with modeling using an extended version of the Mie scattering theory for particles on substrates, enabling the prediction of the PMMS signal magnitude based on the material and substrate properties.

3.
Ultrasound Obstet Gynecol ; 50(2): 215-220, 2017 Aug.
Article in English | MEDLINE | ID: mdl-27392316

ABSTRACT

OBJECTIVES: To determine whether there is beat-to-beat (BTB) variability in the fetal left myocardial performance index (MPI), as evaluated by an automated system, and whether there is a correlation between MPI and fetal heart rate (FHR). METHODS: This was a prospective cross-sectional study of uncomplicated, morphologically normal, singleton pregnancies at 20-38 weeks' gestation. Multiple cineloops for left MPI measurement were acquired during a single examination of each fetus. Raw cineloop data were analyzed by our automated MPI system (intraclass correlation coefficient of 1.0 for any given waveform) to produce a set of MPIs. The corresponding instantaneous FHR was measured for each individual cardiac cycle for which MPI was calculated. RESULTS: Data from 29 fetuses were analyzed; mean MPI was 0.52, mean FHR was 150 beats per min and the median number of cardiac cycles examined per fetus was 70 (interquartile range, 31-115). Marked BTB variability was noted; median coefficient of variation was 10% (range, 5.5-13.9%). FHR was weakly correlated with absolute MPI (r = 0.22; P < 0.05). BTB variation in MPI as a percentage of the mean MPI was not significantly correlated with FHR (r = 0.031; P = 0.146). When standard error of the mean of all MPI values was divided by the mean for each case, it showed that at least four cardiac cycles should be averaged to reduce MPI variability to approximately ± 5%. CONCLUSION: There is significant BTB variability in fetal left MPI, which has an overall weak correlation with FHR. This could be a factor affecting the consistency of MPI values reported by different research groups. Variability would be reduced by averaging 4-5 cardiac cycles per fetus. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.


Subject(s)
Heart Rate, Fetal , Ultrasonography, Prenatal , Ventricular Function, Left , Cross-Sectional Studies , Female , Gestational Age , Humans , Pregnancy , Prospective Studies , Reproducibility of Results
4.
Yearb Med Inform ; (1): 73-86, 2016 Nov 10.
Article in English | MEDLINE | ID: mdl-27830234

ABSTRACT

OBJECTIVES: As wearable sensors take the consumer market by storm, and medical device manufacturers move to make their devices wireless and appropriate for ambulatory use, this revolution brings with it some unintended consequences, which we aim to discuss in this paper. METHODS: We discuss some important unintended consequences, both beneficial and unwanted, which relate to: modifications of behavior; creation and use of big data sets; new security vulnerabilities; and unforeseen challenges faced by regulatory authorities, struggling to keep pace with recent innovations. Where possible, we proposed potential solutions to unwanted consequences. RESULTS: Intelligent and inclusive design processes may mitigate unintended modifications in behavior. For big data, legislating access to and use of these data will be a legal and political challenge in the years ahead, as we trade the health benefits of wearable sensors against the risk to our privacy. The wireless and personal nature of wearable sensors also exposes them to a number of unique security vulnerabilities. Regulation plays an important role in managing these security risks, but also has the dual responsibility of ensuring that wearable devices are fit for purpose. However, the burden of validating the function and security of medical devices is becoming infeasible for regulators, given the many software apps and wearable sensors entering the market each year, which are only a subset of an even larger 'internet of things'. CONCLUSION: Wearable sensors may serve to improve wellbeing, but we must be vigilant against the occurrence of unintended consequences. With collaboration between device manufacturers, regulators, and end-users, we balance the risk of unintended consequences occurring against the incredible benefit that wearable sensors promise to bring to the world.


Subject(s)
Monitoring, Physiologic/instrumentation , Privacy , Confidentiality , Humans , Monitoring, Ambulatory/instrumentation , Wireless Technology
5.
Ultrasound Obstet Gynecol ; 48(4): 496-503, 2016 Oct.
Article in English | MEDLINE | ID: mdl-26423314

ABSTRACT

OBJECTIVE: To compare automated measurements of the fetal left myocardial performance index (MPI) with manual measurements for absolute value, repeatability and waveform acceptability. METHODS: This was a multicenter international online study using images from uncomplicated, morphologically normal singleton pregnancies (16-38 weeks' gestation). Single Doppler ultrasound cardiac cycle images of 25 cases were selected, triplicated and randomized (n = 75). Six senior observers, unaware of the repetition of images, manually calculated MPI for each waveform and the results were compared with automation. Intraobserver repeatability and interobserver reproducibility were assessed using intraclass correlation coefficients (ICCs) and 95% CI. The agreement between each observer's manual MPI measurements and corresponding automated measurements was evaluated using Bland-Altman plots and ICCs with 95% CI. The degree of variation between experts in the classification of fetal MPI waveform quality was assessed using individual cardiac cycle left MPI images previously classified by two authors as 'optimal', 'suboptimal' or 'unacceptable', with 30 images selected for each quality group. Ten images in each category were duplicated and the resulting 120 images were randomized and then classified online by five observers. The kappa statistic (κ) was used to demonstrate interobserver and intraobserver agreement and agreement of classifications by the five observers. RESULTS: The automated measurement software returned the same value for any given image, resulting in an ICC of 1.00. Manual measurements had intraobserver repeatability ICC values ranging from 0.69 to 0.97, and the interobserver reproducibility ICC was 0.78. Comparison of automated vs manual MPI absolute measurements for each observer gave ICCs ranging from 0.77 to 0.96. Interobserver image quality classification agreement gave k = 0.69 (P < 0.001), and the intraobserver agreement was variable (κ ranging from 0.40 to 0.81). CONCLUSIONS: Automated fetal MPI provides superior repeatability and reproducibility to manual methodology. Additionally, experts vary significantly when classifying suitability of fetal MPI waveforms. Automated MPI may facilitate clinical translation by removing human subjectivity. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.


Subject(s)
Echocardiography, Doppler/methods , Fetal Heart/diagnostic imaging , Ultrasonography, Prenatal/methods , Female , Gestational Age , Humans , Observer Variation , Pregnancy , Prospective Studies , Reproducibility of Results , Software
6.
Work ; 50(1): 9-20, 2015.
Article in English | MEDLINE | ID: mdl-25547167

ABSTRACT

BACKGROUND: Military culture and workplace are areas of interest for researchers across disciplines. However, few publications on military culture exist. OBJECTIVE: The purpose of this article is to introduce general concepts regarding the structure and culture of the United States Military and discuss how this creates challenges for reintegrating into the civilian world. METHOD: Topics that will be covered in this article include an overview of the Department of Defense (DoD) and Department of Veterans Affairs (VA), socialization to military culture, the unique features of the military as a workplace, the cultural experiences of military personnel reintegrating back into the community, and the challenges faced by military members and their spouses. RESULTS: The provided information on military culture will expand military cultural competency so that civilian employers can enhance their ability to create supportive workplaces for veterans and military spouses during times of transition and reintegration. DISCUSSION: The unique characteristics of the military culture should be understood by those who work with or plan to work with military populations.


Subject(s)
Military Personnel/psychology , Organizational Culture , Workplace/psychology , Humans , Iraq War, 2003-2011 , United States
7.
Yearb Med Inform ; 9: 135-42, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-25123733

ABSTRACT

OBJECTIVES: The aim of this paper is to discuss how recent developments in the field of big data may potentially impact the future use of wearable sensor systems in healthcare. METHODS: The article draws on the scientific literature to support the opinions presented by the IMIA Wearable Sensors in Healthcare Working Group. RESULTS: The following is discussed: the potential for wearable sensors to generate big data; how complementary technologies, such as a smartphone, will augment the concept of a wearable sensor and alter the nature of the monitoring data created; how standards would enable sharing of data and advance scientific progress. Importantly, attention is drawn to statistical inference problems for which big datasets provide little assistance, or may hinder the identification of a useful solution. Finally, a discussion is presented on risks to privacy and possible negative consequences arising from intensive wearable sensor monitoring. CONCLUSIONS: Wearable sensors systems have the potential to generate datasets which are currently beyond our capabilities to easily organize and interpret. In order to successfully utilize wearable sensor data to infer wellbeing, and enable proactive health management, standards and ontologies must be developed which allow for data to be shared between research groups and between commercial systems, promoting the integration of these data into health information systems. However, policy and regulation will be required to ensure that the detailed nature of wearable sensor data is not misused to invade privacies or prejudice against individuals.


Subject(s)
Datasets as Topic , Monitoring, Ambulatory/instrumentation , Telemetry/instrumentation , Wireless Technology , Confidentiality , Data Mining , Datasets as Topic/standards , Humans , Wireless Technology/standards
8.
Z Gerontol Geriatr ; 46(8): 720-6, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24271252

ABSTRACT

Objective measurement of real-world fall events by using body-worn sensor devices can improve the understanding of falls in older people and enable new technology to prevent, predict, and automatically recognize falls. However, these events are rare and hence challenging to capture. The FARSEEING (FAll Repository for the design of Smart and sElf-adapaive Environments prolonging INdependent livinG) consortium and associated partners strongly argue that a sufficient dataset of real-world falls can only be acquired through a collaboration of many research groups. Therefore, the major aim of the FARSEEING project is to build a meta-database of real-world falls. To establish this meta-database, standardization of data is necessary to make it possible to combine different sources for analysis and to guarantee data quality. A consensus process was started in January 2012 to propose a standard fall data format, involving 40 experts from different countries and different disciplines working in the field of fall recording and fall prevention. During a web-based Delphi process, possible variables to describe participants, falls, and fall signals were collected and rated by the experts. The summarized results were presented and finally discussed during a workshop at the 20th Conference of the International Society of Posture and Gait Research 2012, in Trondheim, Norway. The consensus includes recommendations for a fall definition, fall reporting (including fall reporting frequency, and fall reporting variables), a minimum clinical dataset, a sensor configuration, and variables to describe the signal characteristics.


Subject(s)
Accidental Falls/prevention & control , Actigraphy/standards , Information Storage and Retrieval/standards , Monitoring, Ambulatory/standards , Practice Guidelines as Topic , Telemedicine/standards , Transducers/standards , Actigraphy/instrumentation , Europe , Evidence-Based Medicine , Humans , Monitoring, Ambulatory/instrumentation , Telemedicine/instrumentation
9.
Intern Med J ; 43(2): 174-82, 2013 Feb.
Article in English | MEDLINE | ID: mdl-22471951

ABSTRACT

BACKGROUND: Lung cancer is the leading cause of cancer-related mortality in Australia. Screening using low-dose computed tomography (LDCT) can reduce lung cancer mortality. The feasibility of screening in Australia is unknown. This paper describes the rationale, design and methods of the Queensland Lung Cancer Screening Study. AIMS: The aim of the study is to describe the methodology for a feasibility study of lung cancer screening by LDCT in Australia. METHODS: The Queensland Lung Cancer Screening Study is an ongoing, prospective observational study of screening by LDCT at a single tertiary institution. Healthy volunteers at high risk of lung cancer (age 60-74 years; smoking history ≥30 pack years, current or quit within 15 years; forced expiratory volume in 1s ≥50% predicted) are recruited from the general public through newspaper advertisement and press release. Participants receive a LDCT scan of the chest at baseline, year 1 and year 2 using a multidetector helical computed tomography scanner and are followed up for a total of 5 years. Feasibility of screening will be assessed by cancer detection rates, lung nodule prevalence, optimal management strategies for lung nodules, economic costs, healthcare utilisation and participant quality of life. CONCLUSIONS: Studying LDCT screening in the Australian setting will help us understand how differences in populations, background diseases and healthcare structures modulate screening effectiveness. This information, together with results from overseas randomised studies, will inform and facilitate local policymaking.


Subject(s)
Early Detection of Cancer/methods , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/epidemiology , Tomography, X-Ray Computed/methods , Aged , Early Detection of Cancer/standards , Feasibility Studies , Female , Humans , Male , Middle Aged , Prospective Studies , Queensland/epidemiology , Risk Factors , Tomography, X-Ray Computed/standards
10.
J Laryngol Otol ; 127 Suppl 1: S13-20, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22892109

ABSTRACT

BACKGROUND: Chronic tympanic membrane perforations can cause significant morbidity. The term myringoplasty describes the operation used to close such perforations. A variety of graft materials are available for use in myringoplasty, but all have limitations and few studies report post-operative hearing outcomes. Recently, the biomedical applications of silk fibroin protein have been studied. This material's biocompatibility, biodegradability and ability to act as a scaffold to support cell growth prompted an investigation of its interaction with human tympanic membrane keratinocytes. METHODS AND MATERIALS: Silk fibroin membranes were prepared and human tympanic membrane keratinocytes cultured. Keratinocytes were seeded onto the membranes and immunostained for a number of relevant protein markers relating to cell proliferation, adhesion and specific epithelial differentiation. RESULTS: The silk fibroin scaffolds successfully supported the growth and adhesion of keratinocytes, whilst also maintaining their cell lineage. CONCLUSION: The properties of silk fibroin make it an attractive option for further research, as a potential alternative graft in myringoplasty.


Subject(s)
Fibroins , Keratinocytes/physiology , Myringoplasty/methods , Tissue Scaffolds , Tympanic Membrane Perforation/surgery , Tympanic Membrane/cytology , Adult , Biocompatible Materials , Cell Culture Techniques , Cell Proliferation , Child , Chronic Disease , Fluorescent Antibody Technique , Humans , Keratinocytes/metabolism , Keratinocytes/ultrastructure , Materials Testing/methods , Membrane Proteins/metabolism , Otitis Media, Suppurative/complications , Proto-Oncogene Protein c-ets-1/metabolism , Tissue Engineering/methods , Tympanic Membrane/physiology , Tympanic Membrane Perforation/complications
11.
Z Gerontol Geriatr ; 45(8): 694-706, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23184295

ABSTRACT

Identification of older people most at risk of falling may facilitate early preventative intervention to reduce the likelihood of falls occurring. While many clinical fall risk assessment techniques exist, they often require subjective assessor interpretation, or are not appropriate for unsupervised screening of larger populations owing to a number of issues including safety, ability to reliably perform the assessment, and requirements for unwieldy apparatus. Researchers have more recently attempted to address some of these deficits by instrumenting new or existing physical fall risk assessments with wearable motion sensors to make such assessments more objective, quicker to administer, and potentially more appropriate for deployment for unsupervised use in the community. The objective of this paper is to discuss various practical questions involving sensor-based fall risk assessment (SFRA). Many of the issues discussed contribute to answering the important question of whether SFRA should or can be used in either a supervised or an unsupervised manner, and what possible deployment scenarios exist for it.


Subject(s)
Accelerometry/instrumentation , Accidental Falls/prevention & control , Optical Devices , Risk Assessment/methods , Signal Processing, Computer-Assisted/instrumentation , Activities of Daily Living/classification , Aged , Environment Design , Equipment Design , Gait Disorders, Neurologic/complications , Gait Disorders, Neurologic/diagnosis , Geriatric Assessment/methods , Germany , Homes for the Aged , Humans , Mobility Limitation , Nursing Homes , Rehabilitation Centers
12.
Physiol Meas ; 33(9): 1517-33, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22903004

ABSTRACT

The use of telehealth paradigms for the remote management of patients suffering from chronic conditions has become more commonplace with the advancement of Internet connectivity and enterprise software systems. To facilitate clinicians in managing large numbers of telehealth patients, and in digesting the vast array of data returned from the remote monitoring environment, decision support systems in various guises are often utilized. The success of decision support systems in interpreting patient conditions from physiological data is dependent largely on the quality of these recorded data. This paper outlines an algorithm to determine the quality of single-lead electrocardiogram (ECG) recordings obtained from telehealth patients. Three hundred short ECG recordings were manually annotated to identify movement artifact, QRS locations and signal quality (discrete quality levels) by a panel of three experts, who then reconciled the annotation as a group to resolve any discrepancies. After applying a published algorithm to remove gross movement artifact, the proposed method was then applied to estimate the remaining ECG signal quality, using a Parzen window supervised statistical classifier model. The three-class classifier model, using a number of time-domain features and evaluated using cross validation, gave an accuracy in classifying signal quality of 78.7% (κ = 0.67) when using fully automated preprocessing algorithms to remove gross motion artifact and detect QRS locations. This is a similar level of accuracy to the reported human inter-scorer agreement when generating the gold standard annotation (accuracy = 70-89.3%, κ = 0.54-0.84). These results indicate that the assessment of the quality of single-lead ECG recordings, acquired in unsupervised telehealth environments, is entirely feasible and may help to promote the acceptance and utility of future decision support systems for remotely managing chronic disease conditions.


Subject(s)
Electrocardiography/standards , Telemedicine/standards , Algorithms , Artifacts , Humans , Quality Control , Reproducibility of Results , Signal Processing, Computer-Assisted
13.
Physiol Meas ; 33(3): 465-86, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22370141

ABSTRACT

Accurate systolic and diastolic pressure estimation, using automated blood pressure measurement, is difficult to achieve when the transduced signals are contaminated with noise or interference, such as movement artifact. This study presents an algorithm for automated signal quality assessment in blood pressure measurement by determining the feasibility of accurately detecting systolic and diastolic pressures when corrupted with various levels of movement artifact. The performance of the proposed algorithm is compared to a manually annotated reference scoring (RS). Based on visual representations and audible playback of Korotkoff sounds, the creation of the RS involved two experts identifying sections of the recorded sounds and annotating sections of noise contamination. The experts determined the systolic and diastolic pressure in 100 recorded Korotkoff sound recordings, using a simultaneous electrocardiograph as a reference signal. The recorded Korotkoff sounds were acquired from 25 healthy subjects (16 men and 9 women) with a total of four measurements per subject. Two of these measurements contained purposely induced noise artifact caused by subject movement. Morphological changes in the cuff pressure signal and the width of the Korotkoff pulse were extracted features which were believed to be correlated with the noise presence in the recorded Korotkoff sounds. Verification of reliable Korotkoff pulses was also performed using extracted features from the oscillometric waveform as recorded from the inflatable cuff. The time between an identified noise section and a verified Korotkoff pulse was the key feature used to determine the validity of possible systolic and diastolic pressures in noise contaminated Korotkoff sounds. The performance of the algorithm was assessed based on the ability to: verify if a signal was contaminated with any noise; the accuracy, sensitivity and specificity of this noise classification, and the systolic and diastolic pressure differences between the result obtained from the algorithm and the RS. 90% of the actual noise contaminated signals were correctly identified, and a sample-wise accuracy, sensitivity and specificity of 97.0%, 80.61% and 98.16%, respectively, were obtained from 100 pooled signals. The mean systolic and diastolic differences were 0.37 ± 3.31 and 3.10 ± 5.46 mmHg, respectively, when the artifact detection algorithm was utilized, with the algorithm correctly determined if the signal was clean enough to attempt an estimation of systolic or diastolic pressures in 93% of blood pressure measurements.


Subject(s)
Blood Pressure Determination/methods , Signal Processing, Computer-Assisted , Adult , Algorithms , Electrocardiography , Female , Humans , Male , Oscillometry , Reproducibility of Results
14.
Opt Lett ; 36(14): 2686-8, 2011 Jul 15.
Article in English | MEDLINE | ID: mdl-21765509

ABSTRACT

Commercial 0.5 kW Yb-doped fiber amplifiers have been characterized and found to be suitable for coherent beam combining. Eight such fiber amplifiers have been coherently combined in a tiled-aperture configuration with 78% combining efficiency and total output power of 4 kW. The power-in-the-bucket vertical beam quality of the combined output is 1.25 times diffraction limited at full power. The beam-combining performance is independent of output power.

15.
Poult Sci ; 90(8): 1659-63, 2011 Aug.
Article in English | MEDLINE | ID: mdl-21753200

ABSTRACT

Chicken meat and eggs contaminated with Salmonella result in economic losses in the poultry industry and potential human infection. Intestinal parasites have been shown to lead to a reduction in the utilization of nutrients and performance in poultry. This study provides insight into the immune responses used by hens of 3 genetically distinct chicken lines (broiler, Leghorn, and Fayoumi) in the presence and absence of Salmonella Enteritidis infection. Understanding the range of immune responses used by different lines in response to Salmonella Enteritidis may help the poultry industry genetically select birds that are more pathogen resistant. The splenic mRNA levels of several immune-related genes [IL-6, IL-8, IL-10, IL-18, macrophage inflammatory protein 1ß, interferon (IFN)-γ, transforming growth factor ß1, and regulated upon activation, normal T cell expressed, and secreted (RANTES)] were analyzed by quantitative PCR. Line, challenge, and their interaction were considered fixed effects. Line had a significant effect on the mRNA expression of RANTES (P < 0.02) and IFN-γ (P < 0.03). Broilers expressed significantly more splenic RANTES mRNA than Fayoumis, and significantly more splenic IFN-γ mRNA than Leghorns (P < 0.05). There was a significant interaction of genetic line and challenge on IL-18 (P < 0.02) and IL-6 (P < 0.01) mRNA expression. Although there was a significant interaction of genetic line and challenge for IL-18, Tukey's test analysis only showed differences at a suggestive level (P < 0.1). Bacterial challenge had a significant effect on IL-6 mRNA expression only within the Fayoumi line. Challenged Fayoumis expressed significantly less IL-6 mRNA than nonchallenged Fayoumis (P < 0.05). The observed differences in mRNA expression of selected cytokines support the concept that these distinct genetic lines utilize different immune responses at homeostasis and in response to Salmonella Enteritidis infection.


Subject(s)
Chickens/genetics , Cytokines/metabolism , Poultry Diseases/metabolism , Salmonella Infections, Animal/microbiology , Salmonella enteritidis , Spleen/metabolism , Animals , Cytokines/genetics , Gene Expression Profiling , Gene Expression Regulation/immunology , Poultry Diseases/genetics , Salmonella Infections, Animal/genetics , Salmonella Infections, Animal/metabolism
16.
Poult Sci ; 90(5): 1009-13, 2011 May.
Article in English | MEDLINE | ID: mdl-21489947

ABSTRACT

Vaccines, antibiotics, and other therapeutic agents used to combat disease in poultry generate recurring costs and the potential of residues in poultry products. Enhancing the immune response using alternative approaches such as selection for increased disease resistance or dietary immunomodulation may be effective additions to the portfolio of strategies the industry applies in poultry health management. The objective of this study was to characterize the effects of dietary supplementation with 3 immunomodulators [ascorbic acid, 1,3-1,6 ß-glucans from baker's yeast, and corticosterone] on cytokine gene expression in the spleen of 3 distinct genetic lines of chickens. Relative mRNA expression levels were determined using quantitative reverse transcriptase PCR for IL-1ß, IL-2, inducible nitric oxide synthase, and toll-like receptors 4 and 15, all of which play important roles in chicken immune function. Expression data were analyzed by mixed model analysis. The only significant effect detected was sex effect (P < 0.04) on expression of IL-1ß. The present findings suggest the need for further investigations into the effects of dietary immunomodulators on cytokine gene expression in chickens so as to generate a better understanding of the immunomodulation process.


Subject(s)
Chickens/immunology , Gene Expression Regulation/drug effects , Genes, MHC Class II/physiology , Immunologic Factors/pharmacology , Spleen/metabolism , Animal Feed , Animals , Ascorbic Acid/pharmacology , Corticosterone/pharmacology , Cytokines/genetics , Cytokines/metabolism , Diet/veterinary , Female , Genes, MHC Class II/genetics , Male , beta-Glucans/pharmacology
17.
Physiol Meas ; 32(3): 369-84, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21330696

ABSTRACT

Pulse oximetry has been extensively used to estimate oxygen saturation in blood, a vital physiological parameter commonly used when monitoring a subject's health status. However, accurate estimation of this parameter is difficult to achieve when the fundamental signal from which it is derived, the photoplethysmograph (PPG), is contaminated with noise artifact induced by movement of the subject or the measurement apparatus. This study presents a novel method for automatic rejection of artifact contaminated pulse oximetry waveforms, based on waveform morphology analysis. The performance of the proposed algorithm is compared to a manually annotated gold standard. The creation of the gold standard involved two experts identifying sections of the PPG signal containing good quality PPG pulses and/or noise, in 104 fingertip PPG signals, using a simultaneous electrocardiograph (ECG) signal as a reference signal. The fingertip PPG signals were each 1 min in duration and were acquired from 13 healthy subjects (10 males and 3 females). Each signal contained approximately 20 s of purposely induced artifact noise from a variety of activities involving subject movement. Some unique waveform morphology features were extracted from the PPG signals, which were believed to be correlated with signal quality. A simple decision-tree classifier was employed to arrive at a classification decision, at a pulse-by-pulse resolution, of whether a pulse was of acceptable quality for use or not. The performance of the algorithm was assessed using Cohen's kappa coefficient (κ), sensitivity, specificity and accuracy measures. A mean κ of 0.64 ± 0.22 was obtained, while the mean sensitivity, specificity and accuracy were 89 ± 10%, 77 ± 19% and 83 ± 11%, respectively. Furthermore, a heart rate estimate, extracted from uncontaminated sections of PPG, as identified by the algorithm, was compared with the heart rate derived from an uncontaminated simultaneous ECG signal. The mean error between both heart rate readings was 0.49 ± 0.66 beats per minute (BPM), in comparison to an error value observed without using the artifact detection algorithm of 7.23 ± 5.78 BPM. These results demonstrate that automated identification of signal artifact in the PPG signal through waveform morphology analysis is achievable. In addition, a clear improvement in the accuracy of the derived heart rate is also evident when such methods are employed.


Subject(s)
Oximetry/methods , Wavelet Analysis , Adult , Algorithms , Artifacts , Electrocardiography , Female , Heart Rate/physiology , Humans , Male , Photoplethysmography , Reference Values , User-Computer Interface
18.
Science ; 330(6003): 512-4, 2010 Oct 22.
Article in English | MEDLINE | ID: mdl-20966253

ABSTRACT

The Afrotropical mosquito Anopheles gambiae sensu stricto, a major vector of malaria, is currently undergoing speciation into the M and S molecular forms. These forms have diverged in larval ecology and reproductive behavior through unknown genetic mechanisms, despite considerable levels of hybridization. Previous genome-wide scans using gene-based microarrays uncovered divergence between M and S that was largely confined to gene-poor pericentromeric regions, prompting a speciation-with-ongoing-gene-flow model that implicated only about 3% of the genome near centromeres in the speciation process. Here, based on the complete M and S genome sequences, we report widespread and heterogeneous genomic divergence inconsistent with appreciable levels of interform gene flow, suggesting a more advanced speciation process and greater challenges to identify genes critical to initiating that process.


Subject(s)
Anopheles/genetics , Genetic Speciation , Genome, Insect , Animals , Anopheles/classification , Evolution, Molecular , Female , Gene Flow , Male , Models, Genetic , Polymorphism, Single Nucleotide
19.
Science ; 330(6003): 514-517, 2010 Oct 22.
Article in English | MEDLINE | ID: mdl-20966254

ABSTRACT

Mosquitoes in the Anopheles gambiae complex show rapid ecological and behavioral diversification, traits that promote malaria transmission and complicate vector control efforts. A high-density, genome-wide mosquito SNP-genotyping array allowed mapping of genomic differentiation between populations and species that exhibit varying levels of reproductive isolation. Regions near centromeres or within polymorphic inversions exhibited the greatest genetic divergence, but divergence was also observed elsewhere in the genomes. Signals of natural selection within populations were overrepresented among genomic regions that are differentiated between populations, implying that differentiation is often driven by population-specific selective events. Complex genomic differentiation among speciating vector mosquito populations implies that tools for genome-wide monitoring of population structure will prove useful for the advancement of malaria eradication.


Subject(s)
Anopheles/genetics , Gene Flow , Genes, Insect , Insect Vectors/genetics , Polymorphism, Single Nucleotide/genetics , Animals , Female , Genotype , Malaria
20.
Poult Sci ; 89(8): 1635-41, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20634518

ABSTRACT

Nutritional modulation of the immune system is an often exploited but poorly characterized process. In chickens and other food production animals, dietary enhancement of the immune response is an attractive alternative to antimicrobial use. A yeast cell wall component, beta-1,3/1,6-glucan, augments the response to disease in poultry and other species; however, the mechanism of action is not clear. Ascorbic acid and corticosterone are better characterized immunomodulators. In chickens, the spleen acts both as reservoir and activation site for leukocytes and, therefore, splenic gene expression reflects systemic immune function. To determine effects of genetic line and dietary immunomodulators, chickens of outbred broiler and inbred Leghorn and Fayoumi lines were fed either a basal diet or an experimental diet containing beta-glucans, ascorbic acid, or corticosterone from 56 to 77 d of age. Spleens were harvested, mRNA was isolated, and expression of interleukin (IL)-4, IL-6, IL-18, macrophage inflammatory protein-1beta, interferon-gamma, and phosphoinositide 3-kinase p110gamma transcripts was measured by quantitative reverse transcription PCR. Effects of diet, genetic line, sex, and diet x genetic line interaction on weight gain and gene expression were analyzed. At 1, 2, and 3 wk after starting the diet treatments, birds fed the corticosterone diet had gained less weight compared with birds fed the other diets (P < 0.001). Sex affected expression of IL-18 (P = 0.010), with higher levels in males. There was a significant interaction between genetic line and diet on expression of IL-4, IL-6, and IL-18 (P = 0.021, 0.006, and 0.026, respectively). Broiler line gene expression did not change in response to the experimental diet. Splenic expression of IL-6 was higher in Leghorns fed the basal or ascorbic acid diets, rather than the beta-glucan or corticosterone diets, whereas the opposite relationship was observed in the Fayoumi line. Expression of IL-4 and IL-18 responded to diet only within the Fayoumi line. The differential splenic expression of birds from diverse genetic lines in response to nutritional immunomodulation emphasizes the need for further study of this process.


Subject(s)
Animal Nutritional Physiological Phenomena , Chickens/genetics , Cytokines/genetics , Immunomodulation/genetics , Spleen/immunology , Animal Feed , Animals , Ascorbic Acid/pharmacology , Chickens/immunology , Corticosterone/pharmacology , Cytokines/immunology , DNA Primers , Gene Amplification , Gene Expression Regulation , Immunomodulation/physiology , Interleukin-18/genetics , Interleukin-4/genetics , Interleukin-6/genetics , Phosphatidylinositol 3-Kinases/genetics , RNA, Messenger/genetics , Reverse Transcriptase Polymerase Chain Reaction , Species Specificity , Spleen/drug effects , beta-Glucans/pharmacology
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