Computer Vision Techniques Demonstrate Robust Orientation Measurement of the Milky Way Despite Image Motion.

Many species rely on celestial cues as a reliable guide for maintaining heading while navigating. In this paper, we propose a method that extracts the Milky Way (MW) shape as an orientation cue in low-light scenarios. We also tested the method on both real and synthetic images and demonstrate that the performance of the method appears to be accurate and reliable to motion blur that might be caused by rotational vibration and stabilisation artefacts. The technique presented achieves an angular accuracy between a minimum of 0.00° and a maximum 0.08° for real night sky images, and between a minimum of 0.22° and a maximum 1.61° for synthetic images. The imaging of the MW is largely unaffected by blur. We speculate that the use of the MW as an orientation cue has evolved because, unlike individual stars, it is resilient to motion blur caused by locomotion.

Integrating RGB-thermal image sensors for non-contact automatic respiration rate monitoring.

Respiration rate (RR) holds significance as a human health indicator. Presently, the conventional RR monitoring system requires direct physical contact, which may cause discomfort and pain. Therefore, this paper proposes a non-contact RR monitoring system integrating RGB and thermal imaging through RGB-thermal image alignment. The proposed method employs an advanced image processing algorithm for automatic region of interest (ROI) selection. The experimental results demonstrated a close correlation and a lower error rate between measured thermal, measured RGB, and reference data. In summary, the proposed non-contact system emerges as a promising alternative to conventional contact-based approaches without the associated discomfort and pain.

Antiplatelet and anticoagulation therapy and the risk of pituitary apoplexy in pituitary adenoma patients.

PURPOSE: Pituitary apoplexy can be a life threatening and vision compromising event. Antiplatelet and anticoagulation use has been reported as a contributing factor in pituitary apoplexy (PA). Utilizing one of the largest cohorts in the literature, this study aims to determine the risk of PA in patients on antiplatelet/anticoagulation (AP/AC) therapy. METHODS: A single center, retrospective study was conducted on 342 pituitary adenoma patients, of which 77 patients presented with PA (23%). Several potential risk factors for PA were assessed, including: patient demographics, tumor characteristics, pre-operative hormone replacement, neurologic deficits, coagulation studies, platelet count, and AP/AC therapy. RESULTS: Comparing patients with and without apoplexy, there was no significant difference in the proportion of patients taking aspirin (45 no apoplexy vs. 10 apoplexy; p = 0.5), clopidogrel (10 no apoplexy vs. 4 apoplexy; p = 0.5), and anticoagulation (7 no apoplexy vs. 3 apoplexy; p = 0.7). However, male sex (p-value < 0.001) was a predictor for apoplexy while pre-operative hormone treatment was a protective factor from apoplexy (p-value < 0.001). A non-clinical difference in INR was also noted as a predictor for apoplexy (no apoplexy: 1.01 ± 0.09, apoplexy: 1.07 ± 0.15; p < 0.001). CONCLUSIONS: Although pituitary tumors have a high risk for spontaneous hemorrhage, the use of aspirin is not a risk for hemorrhage. Our study did not find an increased risk of apoplexy with clopidogrel or anticoagulation, but further investigation is needed with a larger cohort. Confirming other reports, male sex is associated with an increased risk for PA.

Noncontact Sensing of Contagion.

The World Health Organization (WHO) has declared COVID-19 a pandemic. We review and reduce the clinical literature on diagnosis of COVID-19 through symptoms that might be remotely detected as of early May 2020. Vital signs associated with respiratory distress and fever, coughing, and visible infections have been reported. Fever screening by temperature monitoring is currently popular. However, improved noncontact detection is sought. Vital signs including heart rate and respiratory rate are affected by the condition. Cough, fatigue, and visible infections are also reported as common symptoms. There are non-contact methods for measuring vital signs remotely that have been shown to have acceptable accuracy, reliability, and practicality in some settings. Each has its pros and cons and may perform well in some challenges but be inadequate in others. Our review shows that visible spectrum and thermal spectrum cameras offer the best options for truly noncontact sensing of those studied to date, thermal cameras due to their potential to measure all likely symptoms on a single camera, especially temperature, and video cameras due to their availability, cost, adaptability, and compatibility. Substantial supply chain disruptions during the pandemic and the widespread nature of the problem means that cost-effectiveness and availability are important considerations.

Is competitive atrial pacing a possible trigger for atrial fibrillation? Observations from the RATE registry.

BACKGROUND: A high incidence of asymptomatic atrial tachycardia and atrial fibrillation (AT/AF) has been recognized in patients with cardiac implantable devices (CIED). The clinical significance of these AT/AF episodes remains unclear. Some "device-detected AT/AF" was previously shown to be triggered by competitive atrial pacing (CAP). OBJECTIVE: To investigate and characterize a potential association between CAP and AT/AF in the largest series of observations to date. METHODS: RATE, a multicenter registry, included 5379 patients with CIEDs followed for approximately 2 years. Electrograms (EGMs) from 1352 patients with AT/AF, CAP, or both were analyzed by experienced adjudicators to assess a causal relationship between AT/AF and CAP onset, duration, and morphology. RESULTS: In 225 patients, 1394 episodes of both AT/AF and CAP were present in the same tracing. CAP and AT/AF were strongly associated (P ≤ .02). AT/AF occurred during the course of the study in 71% of patients with CAP. In 62% of the episodes, expert adjudication concluded that CAP triggered AT/AF. The duration and morphology of triggered and spontaneous AT/AF episodes differed. Spontaneous AT/AF episodes were associated with constant EGM morphology, and were either long or extremely short. CAP-triggered AT/AF more often had variable and shorter cycle length EGMs. The incidence of short AT/AF events was higher among triggered episodes (25% vs 12.8%, P < .002). CONCLUSION: Device-triggered AT/AF due to CAP is likely more common than previously recognized. This AT/AF entity differs from spontaneous AT/AF in duration and morphology. Clinical implications of spontaneous and device-triggered AT/AF may be different.

Body Image Avoidance, Body Dissatisfaction, and Eating Pathology: Is There a Difference Between Male Gym Users and Non-Gym Users?

With research highlighting the increasing prevalence and severity of body image and eating disturbances in males, particularly athletes and regular gymnasium users, the current study examined body image and eating disturbances in a sample of male gym users and non-gym users (N = 180). Based on previous research, it was predicted that male gym users would report greater body image disturbance (e.g., body image avoidance and body dissatisfaction) and eating pathology, compared with non-gym users. Results of the study partially supported hypotheses, revealing body dissatisfaction and eating pathology were significantly increased in male gym users. However, no significant differences were observed in body image avoidance behaviors, though this is likely because of methodological limitations associated with psychometric measures selected. The study provides preliminary evidence that male gym users do experience subclinical eating and body image concerns, with some also experiencing clinically significant symptoms that could be precursors to the later development of an eating disorder. Results of the current study highlight the importance of educating key stakeholders within health and fitness centers, through community-based interventions, to increase awareness regarding male body image and eating disturbances.

A method for achieving super-resolved widefield CARS microscopy.

We propose a scheme for achieving widefield coherent anti-Stokes Raman scattering (CARS) microscopy images with sub-diffraction-limited resolution. This approach adds structured illumination to the widefield CARS configuration [Applied Physics Letters 84, 816 (2004)]. By capturing a number of images at different phases of the standing wave pattern, an image with up to three times the resolution of the original can be constructed. We develop a theoretical treatment of this system and perform numerical simulations for a typical CARS system, which indicate that resolutions around 120 nm are obtainable with the present scheme. As an imaging system, this method combines the advantages of sub-diffraction-limited resolution, endogenous contrast generation, and a wide field of view.

Quantitative SLM-based Differential Interference Contrast imaging.

We describe the implementation of quantitative Differential Interference Contrast (DIC) Microscopy using a spatial light modulator (SLM) as a flexible Fourier filter in the optical path. The experimental arrangement allows for the all-electronic acquisition of multiple phase shifted DIC-images at video rates which are analyzed to yield the optical path length variation of the sample. The resolution of the technique is analyzed by retrieving the phase profiles of polystyrene spheres in immersion oil, and the method is then applied for quantitative imaging of biological samples. By reprogramming the diffractive structure displayed at the SLM it is possible to record the whole set of phase shifted DIC images simultaneously in different areas of the same camera chip. This allows for quantitative snap-shot imaging of a sample, which has applications for the investigation of dynamic processes.

Differential interference contrast imaging using a spatial light modulator.

Differential interference contrast microscopy, imaging by interferometric superposition of two displaced beams passed through a transparent sample, is one of the most sophisticated methods in classical microscopy. Here we demonstrate a versatile electronically controlled variant using a liquid-crystal spatial light modulator that displays a diffractive optical element and steers the beam separation. The orientation and magnitude of the shear angle and the relative phase of the two interfering beams can all be varied at video rates. The technique is demonstrated by imaging polystyrene beads in immersion oil and a sample of red blood cells. The method expands the capabilities of previous implementations of differential interference contrast microscopy by its nonmechanical control over all imaging parameters.

Impact of erythrocyte Duffy antigen genetic polymorphism on the distribution of GroBeta-T, a novel human CXC chemokine.

PURPOSE: Grobeta-T, a human CXC chemokine, has been studied for its potential to mobilize stem cells. Chemokines bind specifically to receptors on target immune cells but also to a homologous erythrocyte blood group antigen, the Duffy Antigen/Receptor for Chemokines (DARC)that is subject to genetic polymorphism in humans.A mutation in the DARC gene is common among African Americans and results in lack of expression of the erythrocyte antigen. We used a combination of in vitro studies of Grobeta-DARC interaction and pharmacokinetic simulation to anticipate the potential impact of this polymorphism on the pharmacokinetics of Grobeta-T. METHODS: [125I]Grobeta-T was incubated in Caucasian blood to characterize the concentration dependence of the blood to plasma concentration ratio (B/P). Affinity and capacity of binding was estimated by Scatchard analysis; specificity was investigated by competitive displacement with a CC chemokine. The B/P value (7 nM) was then determined in blood from 8 African American subjects. Duffy antigen expression was determined by antibody agglutination. A pharmacokinetic model was developed which accounted for blood-cell binding. Simulations were performed to explore effects of dose regimen and DARC expression on the Grobeta-T plasma concentration-time profile. RESULTS: Grobeta-T affinity and capacity for DARC (Caucasian blood)were 23.0 +/- 1.2 and 37.7 +/- 0.6 nM, respectively;excess CC chemokine fully displaced [125I]Grobeta-T. Chemokine binding was highly correlated with the presence or absence of the Duffy antigen (p<0.01) in African American blood; the proportion of subjects for which binding was observed (3/8), was consistent with the reported frequency of DARC expression in this population. Counter to intuition,in the terminal disposition phase at low doses,concentrations of free Grobeta-T in the presence of DARC may be substantially higher than in the absence of DARC. CONCLUSION: Dissociation from the erythrocyte antigen may lead to greater persistence, at low doses, of free Grobetabeta-T in the blood of individuals expressing the chemokine sink.

OH concentration and temperature measurements by use of near-resonant holographic interferometry.

Near-resonant holographic interferometry is demonstrated to measure temperature and species concentration in a two-dimensional steady premixed air-acetylene flame. A peak temperature of (2600 +/- 100) K and a peak OH number density of (9.6 +/- 0.3) x 10(22) m(-3) are obtained, consistent with the expected values for such a flame. These values are determined by recording interferograms with a laser assumed sufficiently detuned from line center so that pressure and temperature broadening can be ignored. The results are thus obtained without making prior assumptions on the temperature or pressure of the flame beyond the existence of thermal equilibrium.

Isotope and elemental effects indicate a rate-limiting methyl transfer as the initial step in the reaction catalyzed by Escherichia coli cyclopropane fatty acid synthase.

Cyclopropane fatty acid (CFA) synthases catalyze the formation of cyclopropane rings on unsaturated fatty acids (UFAs) that are natural components of membrane phospholipids. The methylene carbon of the cyclopropane ring derives from the activated methyl group of S-adenosyl-L-methionine (AdoMet), affording S-adenosyl-L-homocysteine (AdoHcys) and a proton as the remaining products. This reaction is unique among AdoMet-dependent enzymes, because the olefin of the UFA substrate is isolated and unactivated toward nucleophilic or electrophilic addition, raising the question as to the timing and mechanism of proton loss from the activated methyl group of AdoMet. Two distinct reaction schemes have been proposed for this transformation; however, neither was based on detailed in vitro mechanistic analysis of the enzyme. In the preceding paper [Iwig, D. F. and Booker, S. J. (2004) Biochemistry 43, http://dx.doi.org/10.1021/bi048693+], we described the synthesis of two analogues of AdoMet, Se-adenosyl-L-selenomethionine (SeAdoMet) and Te-adenosyl-L-telluromethionine (TeAdoMet), and their intrinsic reactivity toward polar chemistry in which AdoMet is known to be involved. We found that the electrophilicity of AdoMet and its onium congeners followed the series SeAdoMet > AdoMet > TeAdoMet, while the acidity of the carbons adjacent to the relevant heteroatom followed the series AdoMet > SeAdoMet > TeAdoMet. When each of these compounds was used as the methylene donor in the CFA synthase reaction, the kinetic parameters of the reaction, k(cat) and k(cat) K(M)(-1), followed the series SeAdoMet > AdoMet > TeAdoMet, suggesting that the reaction takes place via methyl transfer followed by proton loss, rather than by processes that are initiated by proton abstraction from AdoMet. Use of S-adenosyl-L-[methyl-d(3)]methionine as the methylene donor resulted in an inverse isotope effect of 0.87 +/- 0.083, supporting this conclusion and also indicating that the methyl transfer takes place via a tight s(N)2 transition state.

Near-resonant holographic interferometry and absorption measurements of seeded atomic species in a flame.

The development of near-resonant holographic interferometry techniques for use on flows seeded with atomic species is described. A theoretical model for the refractivity that is due to the seed species is outlined, and an approximation to this model is also described that is shown to be valid for practical regimes of interest and allows the number density of the species to be determined without knowledge of line-broadening effects. The details of quantitative number density experiments performed on an air-acetylene flame are given, and a comparison with an alternative absorption-based experiment is made.

Enhanced flow visualization with near-resonant holographic interferometry.

Holographic interferometry measurements have been performed on high-speed, high-temperature gas flows with a laser output tuned near a resonant sodium transition. The technique allows the detection and quantification of the sodium concentration in the flow. By controlling the laser detuning and seeded sodium concentration, we performed flow visualization in low-density flows that are not normally detectable with standard interferometry. The technique was also successfully used to estimate the temperature in the boundary layer of the flow over a flat plate.

Use of the AutoCapture Pacing System with implantable defibrillator leads.

INTRODUCTION: Previous studies using various bipolar pacemaker leads have shown that the AutoCapture (AC) Pacing System is able to verify ventricular capture and regulate pacing output, increasing patient safety with respect to unexpected threshold changes and potentially prolonging device longevity. An increasing number of patients with implantable cardioverter defibrillators (ICDs) require ventricular pacing that contributes to a shortening of longevity of these systems. This prospective study tested the compatibility of the AC system with bipolar ICD leads. METHODS: The AC algorithm was evaluated prior to ICD testing in 30 ICD recipients. A single coil, active fixation, true bipolar ventricular lead was implanted in 21 patients, and a dual coil, passive fixation, integrated bipolar ventricular lead was implanted in 9 patients. A ventricular evoked response sensitivity test and an AC threshold test were performed using a pacemaker with the ventricular AC algorithm. RESULTS: AC was recommended in 22/30 (73.3%) of implants, including 20/21 (95.2%) with the single coil and 2/9 (22.2%) with the dual coil lead. Mean polarization was lower (1.23 +/- 0.95 mV vs 3.70 +/- 2.33 mV, P = 0.013) while the mean evoked response was higher (18.04 +/- 8.29 mV vs 10.13 +/- 4.22 mV, P = 0.002) with the single coil leads. CONCLUSION: Automatic threshold tracking using the AC is compatible with ICD leads. Leads with lower polarization and greater evoked response are more likely to result in recommendation of AC use. Use of this system offers the potential for increasing ICD generator longevity and improving patient safety in response to late unexpected threshold increases.