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Optics Express Oct 2010A recently introduced two-channel confocal microscope with correlated detection promises up to 50% improvement in transverse spatial resolution [Simon, Sergienko, Optics...
A recently introduced two-channel confocal microscope with correlated detection promises up to 50% improvement in transverse spatial resolution [Simon, Sergienko, Optics Express 18, 9765 (2010)] via the use of photon correlations. Here we achieve similar results in a different manner, introducing a triple-confocal correlated microscope which exploits the correlations present in optical parametric amplifiers. It is based on tight focusing of pump radiation onto a thin sample positioned in front of a nonlinear crystal, followed by coincidence detection of signal and idler photons, each focused onto a pinhole. This approach offers further resolution enhancement in confocal microscopy.
Topics: Algorithms; Amplifiers, Electronic; Equipment Design; Microscopy, Confocal; Models, Statistical; Models, Theoretical; Optics and Photonics; Oscillometry; Photons
PubMed: 20941116
DOI: 10.1364/OE.18.022147 -
Scientific Reports Sep 2018We developed an iPhone X application to measure blood pressure (BP) via the "oscillometric finger pressing method". The user presses her fingertip on both the front...
We developed an iPhone X application to measure blood pressure (BP) via the "oscillometric finger pressing method". The user presses her fingertip on both the front camera and screen to increase the external pressure of the underlying artery, while the application measures the resulting variable-amplitude blood volume oscillations via the camera and applied pressure via the strain gauge array under the screen. The application also visually guides the fingertip placement and actuation and then computes BP from the measurements just like many automatic cuff devices. We tested the application, along with a finger cuff device, against a standard cuff device. The application yielded bias and precision errors of -4.0 and 11.4 mmHg for systolic BP and -9.4 and 9.7 mmHg for diastolic BP (n = 18). These errors were near the finger cuff device errors. This proof-of-concept study surprisingly indicates that cuff-less and calibration-free BP monitoring may be feasible with many existing and forthcoming smartphones.
Topics: Adolescent; Adult; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Female; Fingers; Humans; Male; Middle Aged; Oscillometry; Pressure; Proof of Concept Study; Reproducibility of Results; Sensitivity and Specificity; Smartphone
PubMed: 30177793
DOI: 10.1038/s41598-018-31632-x -
Clinics (Sao Paulo, Brazil) 2024Studies suggest peripheral airway abnormalities in Pulmonary Arterial Hypertension (PAH). Impulse Oscillometry (IOS) is a noninvasive and sensitive technique for...
INTRODUCTION
Studies suggest peripheral airway abnormalities in Pulmonary Arterial Hypertension (PAH). Impulse Oscillometry (IOS) is a noninvasive and sensitive technique for assessing the small airways. It evaluates the impedance of the respiratory system ‒ Resistance (R) and reactance (X) ‒ to a pulse of sound waves sent to the lungs, in a range of frequencies (5‒20 Hz).
METHOD
Resistance variables: R5, R20, R5-R20 and reactance variables: AX (reactance area) and Fres (resonance frequency). The aim is to evaluate R and X in patients with idiopathic PAH (IPAH) and to investigate whether there is a correlation between IOS and spirometry.
RESULTS
Thirteen IPAH patients and 11 healthy subjects matched for sex and age underwent IOS and spirometry. IPAH patients had lower FVC and FEV values (p < 0.001), VEF/CVF (p = 0.049) and FEF 25-75 (p = 0.006) than healthy patients. At IOS, IPAH patients showed lower tidal volumes and higher AX (p < 0.05) compared to healthy individuals, and 53.8 of patients had R5-R20 values ≥ 0.07 kPa/L/s. Correlation analysis: X5, AX, R5-R20 and Fres showed moderate correlation with FVC (p = 0.036 r = 0.585, p = 0.001 r = -0.687, p = 0.005 r = -0.726 and p = 0.027 r = -0.610); Fres (p = 0.012 r = -0.669) and AX (p = 0.006 r = -0.711) correlated with FEV; [R5 and R20, (R5-R20)] also correlated with FEV (p < 0.001 r = -0.573, p = 0.020 r = -0.634 and p = 0.010 r = -0.683, respectively) in the IPAH group. There were also moderate correlations of FEF 25-75 % with Z5 (p = 0.041), R5 (p = 0.018), Fres (p = 0.043) and AX (p = 0.023).
DISCUSSION
Patients showed changes suggestive of increased resistance and reactance in the IOS compared to healthy individuals, and the IOS findings showed a good correlation with spirometry variables.
Topics: Humans; Pulmonary Arterial Hypertension; Oscillometry; Forced Expiratory Volume; Respiratory Function Tests; Lung; Spirometry
PubMed: 38490138
DOI: 10.1016/j.clinsp.2023.100313 -
Journal of Feline Medicine and Surgery Feb 2021This study compared Doppler and oscillometric (PetMAP+) devices (with or without proprietary optimisations) for the non-invasive measurement of blood pressure in...
OBJECTIVES
This study compared Doppler and oscillometric (PetMAP+) devices (with or without proprietary optimisations) for the non-invasive measurement of blood pressure in conscious cats.
METHODS
Twenty-three cats were enrolled; however, five were excluded as fewer than five measurements were obtained for each assessment. All measurements were obtained according to American College of Veterinary Internal Medicine consensus guidelines. Oscillometric device modes A and B were operated according to the manufacturer's guidelines. Doppler and oscillometric devices were used alternately as the first device.
RESULTS
Systolic arterial blood pressure (SAP) measurements were obtained by Doppler (SAPd) and oscillometry; the mean of each set of five values was used for statistical analysis. There was a significant difference between SAPd and SAP measurements in oscillometric modes A ( <0.001) and B ( <0.001). While both modes measured SAP higher than SAPd, B had a smaller bias (+15.72 mmHg) and narrower limits of agreement (LOA). There was also a significant difference between SAPd and mean arterial pressure (MAP) on oscillometric modes A ( = 0.002) and B ( <0.001). Both modes' MAP readings were lower than SAPd and oscillometric A MAP was closer to SAPd (-14.94 mmHg), with a smaller bias and narrower LOA.
CONCLUSIONS AND RELEVANCE
The findings support that Doppler and oscillometric devices cannot be used interchangeably, with or without proprietary optimisations. Methodology should always be taken into account and reference intervals (RIs) need to be defined for the different methodologies. Until methodology-specific RIs are published, definitive diagnosis of hypertension and sub-staging of patients with kidney disease according to the International Renal Interest Society guidelines remains challenging.
Topics: Animals; Blood Pressure; Blood Pressure Determination; Blood Pressure Monitors; Cats; Oscillometry; Ultrasonics; Ultrasonography, Doppler
PubMed: 32580610
DOI: 10.1177/1098612X20932407 -
Journal of Veterinary Internal Medicine Mar 2021Measured indirect blood pressure (BP) results in cats in a clinical environment might be affected by stress and characteristics of the cats.
Influence of clinical setting and cat characteristics on indirectly measured blood pressure and pulse rate in healthy Birman, Norwegian Forest, and Domestic Shorthair cats.
BACKGROUND
Measured indirect blood pressure (BP) results in cats in a clinical environment might be affected by stress and characteristics of the cats.
HYPOTHESIS
To investigate the influence of clinical setting, cat characteristics, and life situation on BP and pulse rate (PR) in healthy cats.
ANIMALS
Ninety-four healthy Domestic Shorthair, Birman and Norwegian Forest cats.
METHODS
Blood pressure measured by high-definition oscillometry in 3 settings: cat placed in its own carrier with veterinarian present; cat placed in carrier with owner alone present; and cat placed on table with veterinarian present. Statistical analyses were performed using mixed linear models.
RESULTS
Systolic BP (SBP) did not differ among settings. Higher mean arterial pressure (MAP), diastolic BP (DBP), and PR were found when measurements were performed with cat placed on table, rather than in carrier. Coefficients of variation (CVs) higher for SBP, MAP, DBP, and PR when measured with cat placed on table than in carrier. Birman cats had lower BP than other breeds. Systolic BP, MAP, DBP, and PR increased with age. Cats allowed outdoors had lower PR than cats living strictly indoors.
CONCLUSION AND CLINICAL IMPORTANCE
No difference in SBP was found among settings, but measuring BP with the cat placed on the examination table gave higher MAP, DBP, PR, and CV than measuring BP with the cat in its carrier. Breed affected BP, with lower BP in Birman cats than other breeds. Blood pressure increased with age. Pulse rate was lower in cats allowed outdoors than cats living strictly indoors.
Topics: Animals; Blood Pressure; Cats; Forests; Heart Rate; Oscillometry
PubMed: 33675246
DOI: 10.1111/jvim.16096 -
PloS One 2023Impulse oscillometry system (IOS) is a simple, and less invasive method for assessing small to total airway resistance in children. We analyzed the correlation between...
Impulse oscillometry system (IOS) is a simple, and less invasive method for assessing small to total airway resistance in children. We analyzed the correlation between IOS, spirometry, and plethysmographic parameters performed for the diagnosis of pediatric BO patients. A total of 89 IOS assessments of pediatric BO patients or children without lung disease were included, and the relationship between pulmonary function tests (PFTs) and diagnostic performance was analyzed. R5, R5-20, X5, and AX were statistically significantly worse in the BO group. In general linear correlation analysis, R5% (adjusted β [aβ], -0.59; p < 0.001) and AX % (aβ, -0.9; p < 0.001) showed the strongest correlation with conventional PFT parameters. R5% and AX % also showed the highest correlation with FEF25-75% (aβ, -0.48; p < 0.001 and aβ, -0.83; p < 0.001), and sRaw % (aβ, -0.73; p = 0.003 and aβ, -0.59; p = 0.008, respectively). Multivariate logistic regression analysis showed that R5 Z-score showed the highest ORs with FEV1 (OR = 3.94, p = 0.006), FEF25-75% (OR = 5.96, p = 0.005), and sRaw % (OR = 4.85, p = 0.022). Receiver operating curve analysis suggested AX % and R5% as the most optimal IOS parameters for BO diagnostic performance with the area under the curve of 0.915 and 0.882, respectively. In conclusion, R5 and AX are the parameters that can independently identify the severity of airway obstruction in pediatric BO patients without conventional lung function tests. IOS is an easy-to-perform, and reliable diagnostic method capable of detecting pathological obliteration of the small airways in children with BO.
Topics: Humans; Child; Oscillometry; Respiratory Function Tests; Lung; Spirometry; Bronchiolitis Obliterans; Forced Expiratory Volume
PubMed: 36749747
DOI: 10.1371/journal.pone.0280309 -
Journal of Clinical Hypertension... Dec 2018The measurement of blood pressure in the office (OBP) remains the basis for hypertension diagnosis and management for more than half a century. Despite the increasing...
The measurement of blood pressure in the office (OBP) remains the basis for hypertension diagnosis and management for more than half a century. Despite the increasing use of out-of-office blood pressure measurement using home and less so ambulatory monitoring and their endorsement by hypertension societies, at present and for some time to come it is likely that in many people the diagnosis and management of hypertension will be based on OBP measurement alone. OBP measurement is a very variable method affected by multiple factors, which have major impact on the OBP level, reproducibility and prognostic ability. Thus, there are several types of OBP measurement, depending on the device type, conditions, observer's presence and the number of readings. The 4 main OBP types are: Type I: Auscultatory OBP in clinical practice; Type II: Automated attended OBP in clinical practice; Type III: Research setting OBP; Type IV: Unattended automated OBP. These OBP types have different standardization level, different reproducibility, different clinical relevance and different thresholds for hypertension diagnosis. Unless the methodological details of OBP measurement are reported, any conclusions based on such measurements in clinical research and in practice are questionable.
Topics: Auscultation; Automation; Blood Pressure; Blood Pressure Determination; Blood Pressure Monitoring, Ambulatory; Humans; Hypertension; Office Visits; Oscillometry; Practice Patterns, Physicians'; Randomized Controlled Trials as Topic; Reproducibility of Results
PubMed: 30402943
DOI: 10.1111/jch.13420 -
Respiratory Care Aug 2016The impulse oscillometry system is a noninvasive method of evaluating respiratory mechanics that is being increasingly used in the pediatric population. To date, no... (Observational Study)
Observational Study
BACKGROUND
The impulse oscillometry system is a noninvasive method of evaluating respiratory mechanics that is being increasingly used in the pediatric population. To date, no reference equations have been developed for healthy Brazilian children and adolescents. The purpose of the study was to determine the reference equations for impulse oscillometry system parameters in healthy children and adolescents.
METHODS
We undertook an observational cross-sectional analytical study with healthy students age 6-14 y from educational institutions in the Greater Florianópolis area. Biometric data were evaluated (weight, height, body mass index, and body surface area) as predictors and for sample characterization. All participants were submitted to evaluation of respiratory mechanics using an oscillometry system following American Thoracic Society standards. Three tests were recorded, with data acquisition for ≥20 s. For data normality verification, the Kolmogorov-Smirnov test was applied, and Pearson's correlation test identified the relationship between the predicted values of height, age, and weight and the oscillometric variables of resistance at 5 and 20 Hz reactance; respiratory impedance at 5 Hz resonant frequency; and reactance area. Models were developed using simple linear regression and multiple analyses.
RESULTS
After the recruitment of 864 children, 123 subjects with an average age of 10.0 ± 2.4 y for boys and 9.9 ± 2.4 y for girls (P = .94) were considered for final analysis. Correlations were identified between the dependent and predictor oscillometric variables, with height identified as having the greatest predictive power in the equations developed for boys in all oscillometric parameters, with a mean adjusted R(2) of 46.51%. Age had greater influence on resonant frequency (adjusted R(2) = 40.1%) and reactance area (adjusted R(2) = 48.8%) for girls.
CONCLUSIONS
Reference equations were developed for males and females, and height was the most influential predictor variable for most impulse oscillometry system parameters in the population studied.
Topics: Adolescent; Age Factors; Body Height; Body Weight; Brazil; Child; Cross-Sectional Studies; Electric Impedance; Female; Humans; Linear Models; Male; Oscillometry; Predictive Value of Tests; Reference Standards; Reference Values; Respiratory Mechanics; Statistics, Nonparametric
PubMed: 27165421
DOI: 10.4187/respcare.04226 -
Respiratory Research Jul 2022To establish the predicted value of pulmonary function determined by impulse oscillometry (IOS) in children (4-17 years old) in China. (Clinical Trial)
Clinical Trial
OBJECTIVE
To establish the predicted value of pulmonary function determined by impulse oscillometry (IOS) in children (4-17 years old) in China.
METHODS
A total of 6270 healthy children aged 4-17 years in China were included. The Master Screen IOS pulmonary function device (Jaeger Co, Germany) was used to detect the respiratory impedance (Zrs), resonant frequency (Fres), respiratory system resistance (Rrs) and respiratory system reactance (Xrs) at various oscillation frequencies, and the indices above were analysed. Stepwise multivariate regression was used to establish the regression equation of related parameters of IOS in different sexes, ages, height, and weight.
RESULTS
The differences in the main IOS parameters between different age stages were statistically significant regardless of sex (P < 0.05). The stepwise multivariate regression analysis showed that IOS parameters were related to height, age, and weight, and most IOS parameters were most closely related to height (the absolute value of the regression coefficient was the largest). With increasing age and height, the values of Z, R, R, R-R, and Fres decreased, while the value of X increased. Through height, age, and weight, we obtained the normal predicted values equation of children's IOS parameters. Compared with the other reference equations, our reference equation is more suitable for Chinese children.
CONCLUSIONS
The study revealed the reference values of IOS parameters in healthy Chinese children. In the evaluation of results for lung function measurements, this predicted value equation is more consistent with the characteristics of Chinese children than other reference equations.
CLINICAL TRIAL
ChiCTR: 1800019029.
Topics: Adolescent; Child; Child, Preschool; China; Humans; Lung; Oscillometry; Reference Values; Respiratory Function Tests; Spirometry
PubMed: 35831898
DOI: 10.1186/s12931-022-02080-z -
Optics Express Mar 2012Semiconductor saturable absorber mirror (SESAM) mode-locked thin disk lasers define the state-of-the-art performance for high average power and high pulse energy... (Review)
Review
Semiconductor saturable absorber mirror (SESAM) mode-locked thin disk lasers define the state-of-the-art performance for high average power and high pulse energy femtosecond laser oscillators. To date pulse energies above 30 µJ and average powers above 140 W have been demonstrated. In this paper we review the achievements of mode-locked thin disk lasers in terms of average power and pulse energy. Stable mode locking requires single transverse mode operation even at the highest average power, which is challenging and therefore addressed in more detail. We then summarize our expectations on the main challenges and limitiations for the next generation of mode-locked thin disk laser oscillators with an average power above 500 W and pulse energies in excess of 100 µJ.
Topics: Amplifiers, Electronic; Equipment Design; Equipment Failure Analysis; Lasers, Semiconductor; Miniaturization; Oscillometry
PubMed: 22453386
DOI: 10.1364/OE.20.007054