Context. The European Space Agency mission Gaia has published, with its second data release (DR2), a catalogue of photometric measurements for more than 1.3 billion astronomical objects in three ...passbands. The precision of the measurements in these passbands, denoted G, GBP, and GRP, reach down to the milli-magnitude level. The scientific exploitation of this data set requires precise knowledge of the response curves of the three passbands. Aims. This work aims to improve the exploitation of the photometric data by deriving an improved set of response curves for the three passbands, allowing for an accurate computation of synthetic Gaia photometry. Methods. This is achieved by formulating the problem of passband determination in a functional analytic formalism, and linking the photometric measurements with four observational, one empirical, and one theoretical spectral library. Results. We present response curves for G, GBP, and GRP that differ from the previously published curves, and which provide a better agreement between synthetic Gaia photometry and Gaia observations.
It has been suggested that many forms of secondary lymphedema in humans are driven by a progressive loss of lymphatic pump function after an initial risk-inducing event. However, the link between ...pump failure and disease progression has remained elusive due to experimental challenges in the clinical setting and a lack of adequate animal models. Using a novel surgical model of lymphatic injury, we track the adaptation and functional decline of the lymphatic network in response to surgery. This model mimics the histological hallmarks of the typical mouse tail lymphedema model while leaving an intact collecting vessel for analysis of functional changes during disease progression. Lymphatic function in the intact collecting vessel negatively correlated with swelling, while a loss of pumping pressure generation remained even after resolution of swelling. By using this model to study the role of obesity in lymphedema development, we show that obesity exacerbates acquired lymphatic pump failure following lymphatic injury, suggesting one mechanism through which obesity may worsen lymphedema. This lymphatic injury model will allow for future studies investigating the molecular mechanisms leading to lymphedema development.
Network analytical metrics often seek to capture the structural dimension of social capital, but such data collections using traditional social research tools often suffer from biases like ...interviewer effects and are usually only suitable to study small groups of participants. Digital sources of social relations might offer great potential for facilitating such measures though, because they digitally store unprecedented amounts of relational data, free from the limitations associated with self-reported data. This study therefore compares individual node degrees collected through a contact diary (i.e., overall-social capital), and a counterpart extracted from digital footprint data from the social media network, Facebook (i.e., social media network-social capital). The findings suggest that researchers conducting empirical studies involving the concept thus should not ignore social media network-social capital as a practical alternative measure of overall-social capital; it provides a sound approximation but only after controlling for other influential factors. In particular, our results highlight that the usability of the digital social capital metric is conditional on the three-way interaction between the variables gender, age, and social media network-social capital. Thus, the evidence from our study, in turn, also intimates that individuals act heterogeneously in the digital sphere with respect to their networking behaviour.
Near-infrared imaging of lymphatic drainage of injected indocyanine green (ICG) has emerged as a new technology for clinical imaging of lymphatic architecture and quantification of vessel function, ...yet the imaging capabilities of this approach have yet to be quantitatively characterized. We seek to quantify its capabilities as a diagnostic tool for lymphatic disease. Imaging is performed in a tissue phantom for sensitivity analysis and in hairless rats for
testing. To demonstrate the efficacy of this imaging approach to quantifying immediate functional changes in lymphatics, we investigate the effects of a topically applied nitric oxide (NO) donor glyceryl trinitrate ointment. Premixing ICG with albumin induces greater fluorescence intensity, with the ideal concentration being
ICG and
albumin. ICG fluorescence can be detected at a concentration of
as deep as 6 mm with our system, but spatial resolution deteriorates below 3 mm, skewing measurements of vessel geometry. NO treatment slows lymphatic transport, which is reflected in increased transport time, reduced packet frequency, reduced packet velocity, and reduced effective contraction length. NIR imaging may be an alternative to invasive procedures measuring lymphatic function
in real time.
The World Health Organization's Global Program to Eliminate Lymphatic Filariasis (LF) has reduced LF transmission worldwide, but millions remain affected by filarial lymphedema. Tools for clinically ...monitoring lymphedema in developing nations are limited. We tested a novel, portable, infrared three-dimensional imaging system (3DIS) against water displacement (WD) and tape measurement of limb circumference (TMLC) among patients with filarial leg lymphedema in Galle, Sri Lanka. Outcomes were accuracy and reproducibility of imaging system measurements. In parallel, we also tested the reproducibility of skin thickness ultrasound (STU) measurements. We examined 52 patients (104 limbs) with lymphedema of stages 0-6 (
= 28, 19, 20, 21, 2, 4, and 10, respectively). 3DIS measurements correlated nearly perfectly with WD (
= 0.9945) and TMLC values (
> 0.9801). The median time required to acquire imaging system measurements for both legs was 2.1 minutes, compared with 17, 7, and 29 minutes, respectively, for WD, TMLC, and STU. Median interexaminer coefficients of variation (CVs) for volume measurements were 1.1% (interquartile range IQR 0.5-2.1%) for WD and 1.7% (IQR 1.2-2.4%) for the 3DIS. CVs for circumference measurements were 1.4% (IQR 0.8-2.4%) by TMLC and 1.3% (0.8-1.9%) by 3DIS. Median interexaminer CV for STU was 13.7% (IQR 8.5-21.3%). The portable imaging system noninvasively provided accurate and reproducible limb volume and circumference measurements in approximately 2 minutes per patient. This portable technology has the potential to greatly improve assessment and monitoring of lymphedema in the clinic and in the field.
Abstract
Background
There are challenges related to the accurate and efficient measurement of lymphedema in people with breast cancer. The LymphaTech 3D Imaging System (LymphaTech, Atlanta, GA, USA) ...is a mobile, noninvasive platform that provides limb geometry measurements.
Objective
The objective of this study was to estimate the reliability and validity of the LymphaTech for measuring arm volume in the context of women seeking care in a specialty breast cancer rehabilitation clinic.
Design
This was a cross-sectional reliability and convergent validity study.
Methods
People who had stage I to IV breast cancer with lymphedema or were at risk for it were included. Arm volume was measured in 66 participants using the LymphaTech and perometer methods. Test-retest reliability for a single measure, limb volume difference, and agreement between methods was analyzed for 30 participants. A method-comparison analysis was also used to assess convergent validity between methods.
Results
Both LymphaTech and perometer methods displayed intraclass correlation coefficients (ICCs) of ≥0.99. The standard errors of measurement for the LymphaTech and length-matched perometer measurements were nearly identical. Similar intraclass correlation coefficients (0.97) and standard errors of measurement (38.0–40.7 mL) were obtained for the between-limb volume difference for both methods. The convergent validity analyses demonstrated no systematic difference between methods.
Limitations
The sample size was not based on a formal sample size calculation. LymphaTech measurements included interrater variance, and perometer measurements contained intrarater variance.
Conclusions
The LymphaTech had excellent test-retest reliability, and convergent validity was supported. This technology is efficient and portable and has a potential role in prospective surveillance and management of lymphedema in clinical, research, and home settings.
While our understanding of the lymphatic system has improved substantially in the past few decades, the translation of this knowledge into improved healthcare solutions for patients suffering from ...secondary lymphedema has been severely limited. The challenge facing clinicians is two-fold. First, there is no reliable, affordable, diagnostic capable of detecting the disease before symptoms of the lymphedema develop and the efficacy of treatment options becomes limited. Second, our understanding of the disease pathogenesis, its risk factors, and the underlying physiologic mechanisms is still in its infancy. These two challenges go hand in hand as limited diagnostic options have hindered our ability to understand lymphedema progression, and the lack of known underlying mechanisms involved in the disease prohibits the development of new diagnostic targets. This review serves to discuss the recent developments in clinical and lab research settings of both lymphedema diagnostic technologies and our understanding of the mechanisms driving disease risk and progression. We will show how these two lines of research are synergistically working with the ultimate goal of improving patient outcomes for those suffering from this horrible disease, identifying key areas of further research that are warranted to move the field forward and provide clinical relief for this neglected patient population.
Lymphedema is a common complication of breast cancer treatment that affects one in five breast cancer survivors, yet there is no reliable method to detect lymphedema in the subclinical range. The ...objective of this study was to determine the feasibility and reliability of using an infrared 3D scanning device (ISD) as a peri-operative limb volume measurement tool.
Fifteen patients were analyzed based on inclusion criteria. Peri-operative measurements were obtained using tape measure and an ISD. Volumes were calculated using a standard algorithm for tape measure and a custom algorithm for ISD measurements. Linear regression models were used to assess ISD and tape measurement volume and circumference correlation. One-way ANOVA was used to compare change in percent difference at set time points post-operatively (2-3 weeks, 4-6 weeks, and 7-12 weeks) for both ISD and tape measure. t tests for unequal variances with the Bonferroni correction were performed among these groups.
There is a positive linear correlation (R
= 0.8518) between absolute volume measurements by the ISD and tape measure. Analyses over 2-10 weeks post-operatively showed that the ISD was able to detect volume changes in both the unaffected and the affected arm. Furthermore, the affected arm tended to have a greater increase in volume in the majority of patients, indicating these patients could be at risk for lymphedema.
Technology utilizing infrared 3D scanners can reliably measure limb volume pre- and post-treatment similarly to tape measure in a small sample of patients. Further research using 3D scanning technology with a longer follow up is warranted.
Cephalopelvic disproportion (CPD)-related obstructed labor is accountable for 3-8% of the maternal deaths worldwide. The consequence of CPD-related obstructive labor in the absence of a Caesarian ...section (C/S) is often maternal or perinatal mortality or morbidity to the mother and/or the infant. Accurate and timely referral of at-risk mothers to health facilities where C/S is a delivery option could reduce maternal mortality in the developing world. The goal of this work was to develop and test the feasibility of a safe, low-cost, easy-to-use, portable tool, using a Microsoft Kinect 3D camera, to identify women at risk for obstructed labor due to CPD. Magnetic resonance imaging (MRI) scans, 3D camera imaging, anthropometry and clinical pelvimetry were collected and analyzed from women 18-40 years of age, at gestational age ≥36+0 weeks with previous C/S due to CPD (n = 43), previous uncomplicated vaginal deliveries (n = 96), and no previous obstetric history (n = 148) from Addis Ababa, Ethiopia. Novel and published CPD risk scores based on anthropometry, clinical pelvimetry, MRI, and Kinect measurements were compared. Significant differences were observed in most anthropometry, clinical pelvimetry, MRI and Kinect measurements between women delivering via CPD-related C/S versus those delivering vaginally. The area under the receiver-operator curve from novel CPD risk scores base on MRI-, Kinect-, and anthropometric-features outperformed novel CPD risk scores based on clinical pelvimetry and previously published indices for CPD risk calculated from these data; e.g., pelvic inlet area, height, and fetal-pelvic index. This work demonstrates the feasibility of a 3D camera-based platform for assessing CPD risk as a novel, safe, scalable approach to better predict risk of CPD in Ethiopia and warrants the need for further blinded, prospective studies to refine and validate the proposed CPD risk scores, which are required before this method can be applied clinically.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The ability to quantify collecting vessel function in a minimally invasive fashion is crucial to the study of lymphatic physiology and the role of lymphatic pump function in disease progression. ...Therefore, we developed a highly sensitive, minimally invasive research platform for quantifying the pumping capacity of collecting lymphatic vessels in the rodent tail and forelimb. To achieve this, we have integrated a near-infrared lymphatic imaging system with a feedback-controlled pressure cuff to modulate lymph flow. After occluding lymphatic flow by inflating a pressure cuff on the limb or tail, we gradually deflate the cuff while imaging flow restoration proximal to the cuff. Using prescribed pressure applications and automated image processing of fluorescence intensity levels in the vessels, we were able to noninvasively quantify the effective pumping pressure (P(eff), pressure at which flow is restored after occlusion) and vessel emptying rate (rate of fluorescence clearance during flow occlusion) of lymphatics in the rat. To demonstrate the sensitivity of this system to changes in lymphatic function, a nitric oxide (NO) donor cream, glyceryl trinitrate ointment (GTNO), was applied to the tails. GTNO decreased P(eff) of the vessels by nearly 50% and the average emptying rate by more than 60%. We also demonstrate the suitability of this approach for acquiring measurements on the rat forelimb. Thus, this novel research platform provides the first minimally invasive measurements of P(eff) and emptying rate in rodents. This experimental platform holds strong potential for future in vivo studies that seek to evaluate changes in lymphatic health and disease.
PDF
