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The electrical solenoid is triggered by using a hand-held push button or a foot pedal that is several feet away from the gantry of the scanner.
This system has provided improved image quality and is safe for the animals, easy to use, and reliable. Premotor neurons encode torsional eye velocity during smooth-pursuit eye movements. Responses to horizontal and vertical ocular pursuit and head and body rotation in multiple planes were recorded in eye movement-sensitive neurons in the rostral vestibular nuclei VN of two rhesus monkeys.
When tested during pursuit through primary eye position, the majority of the cells preferred either horizontal or vertical target motion. During pursuit of targets that moved horizontally at different vertical eccentricities or vertically at different horizontal eccentricities, eye angular velocity has been shown to include a torsional component the amplitude of which is proportional to half the gaze angle "half-angle rule" of Listing's law.
Multiple linear regression analysis revealed a significant contribution of torsional eye movement sensitivity to the responsiveness of the cells. These findings suggest that many VN neurons encode three-dimensional angular velocity , rather than the two-dimensional derivative of eye position, during smooth-pursuit eye movements. Although no clear clustering of pursuit preferred-direction vectors along the semicircular canal axes was observed, the sensitivity of VN neurons to torsional eye movements might reflect a preservation of similar premotor coding of visual and vestibular-driven slow eye movements for both lateral-eyed and foveate species.
Purpose: To study the oxygen saturation SO2 and breath-holding time variation applied active breathing control ABC in radiotherapy of tumor. And the patient monitor was used to observe the oxygen saturation SO2 variation. The variation of SO2, and length of breath-holding time and the time for recovering to the initial value of SO2 were recorded and analyzed. And the breath-holding time shortened obviously for patients whose SO2 did not recover to normal.
It is necessary to check the SO2 variation in breath training, and enough time should be given to recover SO2. We describe a clinical case study surrounding the behavioral assessment and operant treatment of, an adult with severe mental retardation who engaged in chronic breath-holding. In this clinical case, previous neurological and medical testing had ruled out biological bases for the individual's breath-holding.
A functional behavioral assessment…. Agreement and repeatability of vascular reactivity estimates based on a breath-hold task and a resting state scan. By complementing a task-related BOLD acquisition with a vascular reactivity measure obtained through breath-holding or hypercapnia, this unwanted variance can be statistically reduced in the BOLD responses of interest. Recently, it has been suggested that vascular reactivity can also be estimated using a resting state scan.
This study aimed to compare three breath-hold based analysis approaches block design, sine—cosine regressor and CO2 regressor and a resting state approach CO2 regressor to measure vascular reactivity.
We tested BOLD variance explained by the model and repeatability of the measures. Fifteen healthy participants underwent a breath-hold task and a resting state scan with end-tidal CO2 being recorded during both. Maps and regional vascular reactivity estimates showed high repeatability when the breath-hold task was used. Repeatability and variance explained by the CO2 trace regressor were lower for the resting state data based approach, which resulted in highly variable measures of vascular reactivity.
We conclude that breath-hold based vascular reactivity estimations are more repeatable than resting-based estimates, and that there are limitations with replacing breath-hold scans by resting state scans for vascular reactivity assessment.
Both CO 2 inhalation followed by hyperventilation and breath-holding have been utilized to measure cerebral vasomotor reactivity VMR but their correlation has been poorly studied and understood.
A retrospective study was conducted in subjects The mean BHI was 0. Move dish and sample into the cell culture This study aimed to compare three breath-hold based analysis approaches block design, sine-cosine regressor and CO2 regressor and a resting state approach CO2 regressor to measure vascular reactivity. Published by Elsevier Inc. Boson sampling is a problem strongly believed to be intractable for classical computers, but can be naturally solved on a specialized photonic quantum simulator.
The protocol requires only one single-photon source, two detectors, and a loop-based interferometer for an arbitrary number of photons. The single-photon pulse train is time-bin encoded and deterministically injected into an electrically programmable multimode network. The observed three- and four-photon boson sampling rates are Volumetric velocity measurements in restricted geometries using spiral sampling : a phantom study. The aim of this study was to evaluate the accuracy of maximum velocity measurements using volumetric phase-contrast imaging with spiral readouts in a stenotic flow phantom.
In a phantom model, maximum velocity , flow, pressure gradient, and streamline visualizations were evaluated using volumetric phase-contrast magnetic resonance imaging MRI with velocity encoding in one extending on current clinical practice and three directions for characterization of the flow field using spiral readouts. Results of maximum velocity and pressure drop were compared to computational fluid dynamics CFD simulations, as well as corresponding low-echo-time TE Cartesian data.
Flow was compared to 2D through-plane phase contrast PC upstream from the restriction. Results obtained with 3D through-plane PC as well as 4D PC at shortest TE using a spiral readout showed excellent agreements with the maximum velocity values obtained with CFD velocity location, as well as the accurate velocity quantification can be obtained in stenotic regions using short-TE spiral volumetric PC imaging.
Marijuana smoking: effects of varying puff volume and breathhold duration. Two studies were conducted to quantify biological and behavioral effects resulting from exposure to controlled doses of marijuana smoke. Each study also varied levels of delta 9-tetrahydro-cannabinol marijuana cigarette content 1. Subjects smoked 10 puffs in each of six sessions; a seventh, nonsmoking session all measures recorded at the same times as in active smoking sessions served as a control.
Variations in puff volume produced significant dose-related changes in postsmoking plasma delta 9-tetrahydro-cannabinol levels, carbon monoxide boost and subjective effects e.
In contrast, breathholding for 10 or 20 sec versus 0 sec increased plasma delta 9-tetrahydro-cannabinol levels but not CO boost or subjective effects. Task performance measures were not reliably influenced by marijuana smoke exposure within the dosing ranges examined. These findings confirm the utility of the controlled smoking technology, support the notion that cumulative puff volume systematically influences biological exposure and subjective effects, but cast doubt on the common belief that prolonged breathholding of marijuana smoke enhances classical subjective effects associated with its reinforcing value in humans.
Zhang, Ziheng; Dione, Donald P. A novel MR imaging technique, spatial modulation of magnetization with polarity alternating velocity encoding SPAMM-PAV , is presented to simultaneously examine the left ventricular early diastolic temporal relationships between myocardial deformation and intra-cavity hemodynamics with a high temporal resolution of 14 ms.
This approach is initially evaluated in a dynamic flow and tissue mimicking phantom. A comparison of regional longitudinal strains and intra-cavity pressure differences integration of computed in-plane pressure gradients within a selected region in relation to mitral valve inflow velocities is performed in eight normal volunteers.
Our results demonstrate that apical regions have higher strain rates 0. This pattern is reversed during the deceleration period, when the strain-rates in the basal regions are the highest 0.
A positive base-to-apex gradient in peak pressure difference is observed during acceleration, followed by a negative base-to apex gradient during deceleration. These studies shed insight into the regional volumetric and pressure difference changes in the left ventricle during early diastolic filling. Breast tumor hemodynamic response during a breath-hold as a biomarker to predict chemotherapeutic efficacy: preclinical study. Therefore, it requires a perturbation of physiological signals, such as blood flow and oxygenation.
In that sense, a few groups reported that monitoring a relative hemodynamic change during a breast tissue compression or a breath-hold to a patient can provide good contrast between tumor and nontumor. However, no longitudinal study reports the utilization of a breath-hold to predict tumor response during chemotherapy. A continuous wave near-infrared spectroscopy was employed to monitor hemodynamics in rat breast tumor during a hyperoxic to normoxic inhalational gas intervention to mimic a breath-hold during tumor growth and chemotherapy.
The reduced oxyhemoglobin concentration during inhalational gas intervention correlated well with tumor growth, and it responded one day earlier than the change of tumor volume after chemotherapy.
In conclusion, monitoring tumor hemodynamics during a breath-hold may serve as a biomarker to predict chemotherapeutic efficacy of tumor. Left ventricle changes early after breath-holding in deep water in elite apnea divers. To study by ultrasounds cardiac morphology and function early after breath-hold diving in deep water in elite athletes. Each subject performed a series of three consecutive breath-hold dives and 40 m depth. End-diastolic left ventricular LV diameter EDD and end-diastolic LV volume EDV increased significantly p breath-hold diving due to favorable changes in loading conditions relative to pre-diving, namely the recruitment of left ventricular preload reserve and the reduction in afterload.
Dark chocolate reduces endothelial dysfunction after successive breath-hold dives in cool water. The aim of this study is to observe the effects of dark chocolate on endothelial function after a series of successive apnea dives in non-thermoneutral water. Twenty breath-hold divers were divided into two groups: a control group 8 males and 2 females and a chocolate group 9 males and 1 female.
The chocolate group performed the dives 1 h after ingestion of 30 g of dark chocolate. A significant decrease in FMD was observed in the control group after the dives No differences in digital photoplethysmography and peroxynitrites were observed between before and after the dives.
Antioxidants contained in dark chocolate scavenge free radicals produced during breath-hold diving. Ingestion of 30 g of dark chocolate 1 h before the dive can thus prevent endothelial dysfunction which can be observed after a series of breath-hold dives.
Validation of high temporal resolution spiral phase velocity mapping of temporal patterns of left and right coronary artery blood flow against Doppler guidewire. Temporal patterns of coronary blood flow velocity can provide important information on disease state and are currently assessed invasively using a Doppler guidewire.
A non-invasive alternative would be beneficial as it would allow study of a wider patient population and serial scanning. A retrospectively-gated breath-hold spiral phase velocity mapping sequence TR 19 ms was developed at 3 Tesla. Velocity maps were acquired in 8 proximal right and 15 proximal left coronary arteries of 18 subjects who had previously had a Doppler guidewire study at the time of coronary angiography.
Cardiovascular magnetic resonance CMR velocity -time curves were processed semi-automatically and compared with corresponding invasive Doppler data. High temporal resolution breath-hold spiral phase velocity mapping underestimates absolute values of coronary flow velocity but allows accurate assessment of the temporal patterns of blood flow.
MR imaging of the human heart without explicit cardiac synchronization promises to extend the applicability of cardiac MR to a larger patient population and potentially expand its diagnostic capabilities.
However, conventional non-gated imaging techniques typically suffer from low image quality or inadequate spatio-temporal resolution and fidelity. Patient-Adaptive Reconstruction and Acquisition in Dynamic Imaging with Sensitivity Encoding PARADISE is a highly-accelerated non-gated dynamic imaging method that enables artifact-free imaging with high spatio-temporal resolutions by utilizing novel computational techniques to optimize the imaging process. In addition to using parallel imaging, the method gains acceleration from a physiologically-driven spatio-temporal support model; hence, it is doubly accelerated.
The support model is patient-adaptive, i. The proposed method is also doubly adaptive as it adapts both the acquisition and reconstruction schemes. Based on the theory of time-sequential sampling , the proposed framework explicitly accounts for speed limitations of gradient encoding and provides performance guarantees on achievable image quality.
Determination of ethane, pentane and isoprene in exhaled air--effects of breath-holding , flow rate and purified air. Exhaled ethane, pentane and isoprene have been proposed as biomarkers of oxidative stress. The objectives were to explore whether ethane, pentane and isoprene are produced within the airways and to explore the effect of different sampling parameters on analyte concentrations.
The flow dependency of the analyte concentrations, the concentrations in dead-space and alveolar air after breath-holding and the influence of inhaling purified air on analyte concentrations were investigated. The analytical method involved thermal desorption from sorbent tubes and gas chromatography.
The studied group comprised 13 subjects with clinically stable asthma and 14 healthy controls. After breath-holding , no significant changes in ethane levels were observed.
Pentane and isoprene levels increased significantly after 20 s of breath-holding. Inhalation of purified air before exhalation resulted in a substantial decrease in ethane levels, a moderate decrease in pentane levels and an increase in isoprene levels. The major fractions of exhaled ethane, pentane and isoprene seem to be of systemic origin.
There was, however, a tendency for ethane to be flow rate dependent in asthmatic subjects, although to a very limited extent, suggesting that small amounts of ethane may be formed in the airways. Double-blind, placebo-controlled trial on the effect of piracetam on breath-holding spells. Breath-holding spells BHS are apparently frightening events occurring in otherwise healthy children.
The aim of this study was to evaluate the efficacy of piracetam in the treatment of breath-holding spells. Forty patients with BHS who were classified into two groups were involved in a double-blinded placebo-controlled prospective study. Piracetam was given to group A while group B received placebo.
Patients were followed monthly for a total period of 4 months. There was a significant decline of number of attacks after piracetam treatment compared to placebo p value breath-holding spells in children.
Evaluation of correlation between physical properties and ultrasonic pulse velocity of fired clay samples. The aim of this study is to establish a correlation between physical properties and ultrasonic pulse velocity of clay samples fired at elevated temperatures.
Brick-making clay and pottery clay were studied for this purpose. A commercial ultrasonic testing instrument Proceq Pundit Lab was used to evaluate the ultrasonic pulse velocity measurements for each fired clay sample as a function of temperature.
It was observed that there became a relationship between physical properties and ultrasonic pulse velocities of the samples. The results showed that in consequence of increasing densification of the samples , the differences between the ultrasonic pulse velocities were higher with increasing temperature.
These findings may facilitate the use of ultrasonic pulse velocity for the estimation of physical properties of fired clay samples. In a series of breath-hold acquisitions, three-dimensional data were acquired initially for prospective image registration of subsequent BOLD measurements.
Prospective image registration and BOLD imaging of each kidney was achieved within a total measurement time of about 17 s, enabling its execution within a single breath-hold.
Magn Reson Med , Sensory neurons integrate information about the world, adapting their sampling to its changes. However, little is understood mechanistically how this primary encoding process, which ultimately limits perception, depends upon stimulus statistics.
Here, we analyze this open question systematically by using intracellular recordings from fly Drosophila melanogaster and Coenosia attenuata photoreceptors and corresponding stochastic simulations from biophysically realistic photoreceptor models. Simulations reveal how a photoreceptor's information capture depends critically upon the stochastic refractoriness of its 30, sampling units microvilli. In daylight, refractoriness sacrifices sensitivity to enhance intensity changes in neural image representations, with more and faster microvilli improving encoding.
But for GWN and other stimuli, which lack longer dark contrasts of real-world intensity changes that reduce microvilli refractoriness, these performance gains are submaximal and energetically costly. Decompression sickness in breath-hold divers: a review. Although it has been generally assumed that the risk of decompression sickness is virtually zero during a single breath-hold dive in humans, repeated dives may result in a cumulative increase in the tissue and blood nitrogen tension.
Many species of marine mammals perform extensive foraging bouts with deep and long dives interspersed by a short surface interval, and some human divers regularly perform repeated dives to m or a single dive to more than m, all of which may result in nitrogen concentrations that elicit symptoms of decompression sickness.
Neurological problems have been reported in humans after single or repeated dives and recent necropsy reports in stranded marine mammals were suggestive of decompression sickness-like symptoms. Modelling attempts have suggested that marine mammals may live permanently with elevated nitrogen concentrations and may be at risk when altering their dive behaviour. In humans, non-pathogenic bubbles have been recorded and symptoms of decompression sickness have been reported after repeated dives to modest depths.
The mechanisms implicated in these accidents indicate that repeated breath-hold dives with short surface intervals are factors that predispose to decompression sickness. Optimising diffusion-weighted MR imaging for demonstrating pancreatic cancer: a comparison of respiratory-triggered, free-breathing and breath-hold techniques.
Two radiologists, independently and blindly, assigned total image quality scores [sum of rating diffusion images lesion detection, anatomy, presence of artefacts and ADC maps lesion characterisation, overall image quality ] per technique and ranked them.
Total image quality scores for respiratory-triggered, free-breathing and breath-hold techniques were The respiratory-triggered technique had a significantly higher ranking.
Lesion SI on all b-values and signal-to-noise ratio on b and b were significantly higher for the respiratory-triggered technique. For respiratory-triggered, free-breathing and breath-hold techniques the mean ADCs were 1. Anonymized images were randomized for blinded review by two independent readers for image quality, artifact severity in 8 defined vessel segments and aortic dimensions in 6 standard sites.
Comparison and reproducibility of ADC measurements in breathhold , respiratory triggered, and free-breathing diffusion-weighted MR imaging of the liver. To compare and determine the reproducibility of apparent diffusion coefficient ADC measurements of the normal liver parenchyma in breathhold , respiratory triggered, and free-breathing diffusion-weighted magnetic resonance imaging DWI.
Eleven healthy volunteers underwent three series of DWI. ADCs of the liver parenchyma were compared by using nonparametric tests. Reproducibility was assessed by the Bland-Altman method. ADC measurements of the normal liver parenchyma in respiratory triggered DWI are significantly higher and less reproducible than in breathhold and free-breathing DWI. Copyright c Wiley-Liss, Inc. Qualitative assessment of contrast-enhanced magnetic resonance angiography using breath-hold and non-breath-hold techniques in the portal venous system.
The purpose of this study is to evaluate the image quality in delineation of the portal venous systems with two different methods, breath-hold and non-breath-hold by using the 3D FLASH sequence. We used a 1. Our study showed contrast-enhanced 3D FLASH MR angiography, together with the breath-hold technique, may provide reliable and accurate information on the portal venous system.
Time-instant sampling based encoding of time-varying acoustic spectrum. The inner ear has been shown to characterize an acoustic stimuli by transducing fluid motion in the inner ear to mechanical bending of stereocilia on the inner hair cells IHCs. Subsequently, the afferent auditory nerve fiber ANF bundle samples the encoded waveform in the IHCs by synapsing with them. In this work we focus on sampling of information by afferent ANFs from the IHCs, and show computationally that sampling at specific time instants is sufficient for decoding of time-varying acoustic spectrum embedded in the acoustic stimuli.
The approach is based on sampling the signal at its zero-crossings and higher-order derivative zero-crossings. We show results of the approach on time-varying acoustic spectrum estimation from cricket call signal recording.
The framework gives a time-domain and non-spatial processing perspective to auditory signal processing. The approach works on the full band signal, and is devoid of modeling any bandpass filtering mimicking the BM action.
Instead, we motivate the approach from the perspective of event-triggered sampling by afferent ANFs on the stimuli encoded in the IHCs. Though the approach gives acoustic spectrum estimation but it is shallow on its complete understanding for plausible bio-mechanical replication with current mammalian auditory mechanics insights. Reflex anoxic seizures 'white breath-holding ' : nonepileptic vagal attacks.
From clinical history 58 children were diagnosed as having reflex anoxic seizures secondary to provoked cardioinhibition also known as white breath-holding attacks. Before referral, these seizures were commonly misdiagnosed as epileptic either because the provocation was ignored, not recognised, or was a febrile illness, or because there was no crying, no obvious breath-holding , little cyanosis, and often no pallor to suggest syncope and cerebral ischaemia.
The duration of cardiac asystole after ocular compression was measured in these children and in 60 additional children with other paroxysmal disorders. Review of the literature supports the concept that these seizures result from vagal-mediated reflex cardiac arrest which can if necessary be prevented by atropine.
The simple name 'vagal attack' is proposed. Images Figs. This work was aimed at estimating the concentrations of proteins encoded by human chromosome 18 Chr 18 in plasma samples of 54 healthy male volunteers aged These young persons have been certified by the medical evaluation board as healthy subjects ready for space flight training. Over stable isotope-labeled peptide standards SIS were synthesized to perform the measurements of proteins encoded by Chr These proteins were quantified in whole and depleted plasma samples.
A minor part of the proteins mostly representing intracellular proteins was characterized by extremely high inter individual variations. The results provide a background for studies of a potential biomarker in plasma among proteins encoded by Chr Breath-holding spells may be associated with maturational delay in myelination of brain stem. To evaluate possible contribution of maturational delay of brain stem in the etiology of breath-holding spells in children using brain stem auditory evoked potentials.
The study group included children who experienced breath-holding spells. The control group consisted of healthy age- and sex-matched children. Age, gender, type and frequency of spell, hemoglobin, and ferritin levels in study group and brain stem auditory evoked potentials results in both groups were recorded. Study group was statistically compared with control group for brain stem auditory evoked potentials. The mean age of study and control groups was The III-V and I-V interpeak latencies were significantly prolonged in the study group compared with the control group 2.
At the same time, III-V and I-V interpeak latencies of patients without anemia in the study group compared with those of control group were significantly prolonged 2. Our results consider that maturational delay in myelination of brain stem may have a role in the etiology of breath-holding spells in children. Hall effect encoding of brushless dc motors.
Encoding mechanism integral to the motor and using the permanent magnets embedded in the rotor eliminates the need for external devices to encode information relating the position and velocity of the rotating member.
Preliminary observations on the effect of hypoxic and hyperbaric stress on pulmonary gas exchange in breath-hold divers. Pulmonary diffusing capacity to carbon monoxide DLCO and nitric oxide DLNO , haemoglobin Hb and haematocrit Hct were measured in six elite divers before and at 2, 10 and 25 minutes after a maximal breath-hold dive to a depth of 10 metres' sea water. Compared to pre-dive, DLCO showed a slight increase at 2 minutes in five subjects and a tendency to decrease at 25 minutes P breath-hold dive.
Recent advances in echocardiography allow real-time 3-D dynamic image acquisition of the heart. However, one of the major limitations of 3-D echocardiography is the limited field of view, which results in an acquisition insufficient to cover the whole geometry of the heart. This study proposes the novel approach of fusing multiple 3-D echocardiography images using an optical tracking system that incorporates breath-hold position tracking to infer that the heart remains at the same position during different acquisitions.
The proposed method yielded a field of view improvement of To improve the quality of the fused image, a wavelet-based fusion algorithm was developed that computes pixelwise likelihood values for overlapping voxels from multiple image views. The proposed wavelet-based fusion approach yielded significant improvement in contrast The new data confirm the cylindrical rotation observed at -6 Degree-Sign and -8 Degree-Sign and are an excellent fit to themore » Shen et al.
N-body bar model. Our survey finds no strong evidence of previously unknown kinematic streams. We also publish our complete catalog of radial velocities , photometry, TiO band strengths, and spectra, which is available at the Infrared Science Archive as well as at UCLA. The effect of deep inspiration breath-hold on tumour oxygenation. To investigate the influence of deep inspiration breath-hold on the oxygen tension of in-vivo tumours measured using an Eppendorf pO2 histograph. Change in oxygen tension was assessed using the Wilcoxon Signed Ranks test.
Thirty patients were entered in to this protocol. The median maximum tumour dimension was 4 cm. The median of the median pO2 of these tumours was 18 mmHg.
Oxygen tension measurements along pairs of tracks per tumour median of 2 were obtained. In six tumours, the values during NB were significantly higher than during DIBH, whereas, for six other tumours, the relationship was the opposite; for the remaining 18 patients, no significant difference was observed.
These data show heterogeneity of tumour oxygenation seen with in-situ tumours both at baseline and as a result of DIBH. Sherrah, Andrew G. Background Chronic descending thoracic aortic dissection CDTAD following surgical repair of ascending aortic dissection requires long-term imaging surveillance. We investigated four-dimensional 4D -flow magnetic resonance imaging MRI with a novel multi- velocity encoding multi-VENC technique as an emerging clinical method enabling the dynamic quantification of blood volume and velocity throughout the cardiac cycle.
Measuring vascular reactivity with resting-state blood oxygenation level-dependent BOLD signal fluctuations: A potential alternative to the breath-holding challenge? Measurement of the ability of blood vessels to dilate and constrict, known as vascular reactivity, is often performed with breath-holding tasks that transiently raise arterial blood carbon dioxide P a CO 2 levels. However, following the proper commands for a breath-holding experiment may be difficult or impossible for many patients.
In this study, we evaluated two approaches for obtaining vascular reactivity information using blood oxygenation level-dependent signal fluctuations obtained from resting-state functional magnetic resonance imaging data: physiological fluctuation regression and coefficient of variation of the resting-state functional magnetic resonance imaging signal.
This technique may eliminate the need for subject cooperation, thus allowing the evaluation of vascular reactivity in a wider range of clinical and research conditions in which it may otherwise be impractical. An improved target velocity sampling algorithm for free gas elastic scattering. We present an improved algorithm for sampling the target velocity when simulating elastic scattering in a Monte Carlo neutron transport code that correctly accounts for the energy dependence of the scattering cross section.
The algorithm samples the relative velocity directly, thereby avoiding a potentially inefficient rejection step based on the ratio of cross sections. Here, we have shown that this algorithm requires only one rejection step, whereas other methods of similar accuracy require two rejection steps. The method was verified against stochastic and deterministic reference results for upscattering percentages in U. Whole-heart magnetic resonance coronary angiography with multiple breath-holds and automatic breathing-level tracking.
Whole-heart WH magnetic resonance coronary angiography MRCA studies are usually performed during free breathing while monitoring the position of the diaphragm with real-time motion correction. However, this results in a long scan time and the patient's breathing pattern may change, causing the study to be aborted.
However, one problem in the mBH method is that patients cannot hold their breath at the same position every time, leading to image degradation. We have developed a new WH MRCA imaging method that employs both the mBH method and automatic breathing-level tracking to permit automatic tracking of the changes in breathing or breath-hold levels.
Evaluation of its effects on WH MRCA image quality showed that this method can provide high-quality images within a shorter scan time. Reproducible deep-inspiration breath-hold irradiation with forward intensity-modulated radiotherapy for left-sided breast cancer significantly reduces cardiac radiation exposure compared to inverse intensity-modulated radiotherapy.
To investigate the objective utility of our clinical routine of reproducible deep-inspiration breath-hold irradiation for left-sided breast cancer patients on reducing cardiac exposure. Free-breathing and reproducible deep-inspiration breath-hold scans were evaluated for our 10 consecutive left-sided breast cancer patients treated with reproducible deep-inspiration breath-hold. Both inverse and forward intensity-modulated radiotherapy plans were generated for each computed tomography dataset.
Reproducible deep-inspiration breath-hold plans with forward intensity-modulated radiotherapy significantly spared the heart and left anterior descending artery compared to generated free-breathing plans based on mean doses - free-breathing vs reproducible deep-inspiration breath-hold , left ventricle Reproducible deep-inspiration breath-hold and free-breathing plans with inverse intensity-modulated radiotherapy provided similar organ at risk sparing by reducing the mean doses to the left ventricle, left anterior descending artery, heart, VV20 of the heart and right ventricle.
However, forward intensity-modulated radiotherapy showed significant reduction in doses to the left ventricle, left anterior descending artery, heart, right ventricle, and contralateral breast mean dose, The mean doses for free-breathing vs reproducible deep-inspiration breath-hold of the proximal left anterior descending artery were 1.
A method is presented that combines steady-state free precession SSFP cine imaging with myocardial tagging. Imaging is continued immediately after tagging preparation, using linearly increasing startup angles LISA with a rampup over 10 pulses. Interleaved segmented k-space ordering is used to prevent artifacts from the increasing signal during the LISA rampup. The measurements were performed in phantoms and in six subjects applying breathhold cine imaging with tagging temporal resolution 51 ms.
The results show that ghost artifacts are negligible for the LISA method. Copyright Wiley-Liss, Inc. The effect of CO2 on ventilation and breath-holding during exercise and while breathing through an added resistance. Ventilation was measured while subjects were made to rebreathe from a bag containing CO 2 and O 2 in order to expose them to a steadily rising CO 2 tension P CO2. The object of the experiments was to determine the effect of a variety of stimuli upon the increase in ventilation and fall in breath-holding time which occurs in response to the rising P CO2.
Steady-state exercise at kg. These results have been interpreted with the aid of a model of the control of breath-holding and it is suggested that there is no change in CO 2 sensitivity on exercise, either during rebreathing or breath-holding. An increase in the resistance to breathing caused a marked reduction in S V and B V , but no change in the breath-holding-CO 2 response curve. These findings suggest that the flattening of the ventilation-CO 2 response curve is mechanical in origin and acute airway obstruction produces no change in CO 2 sensitivity.
On the basis of these results, we suggest that more information about CO 2 sensitivity can be obtained by a combination of ventilation and breath-holding-CO 2 response curves. Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples. We report on changes in P and S-wave velocities and rock microstructure induced by devolatilization reactions using gypsum as a reference analog material.
Cylindrical samples of natural alabaster were dehydrated in air, at ambient pressure, and temperatures between and K. Concurrently, P and S-wave velocities linearly decreased with porosity from 5. It is concluded that a linearized empirical Raymer-type model extended by a critical porosity term and based on the respective time dependent mineral and pore volumes reasonably replicates the P and S-wave data in relation to reaction progress and porosity.
This study determined 1 how many vessels i. Functional slitlamp biomicroscope was used to image hundreds of venules per subject. The bulbar conjunctiva in five healthy human subjects was imaged on six different locations in the temporal bulbar conjunctiva. The histograms of the diameter and velocity were plotted to examine whether the distribution was normal.
Standard errors were calculated from the standard deviation and vessel sample size. The ratio of the standard error of the mean over the population mean was used to determine the sample size cutoff. The velocity was plotted as a function of the vessel diameter to display the distribution of the diameter and velocity. The distributions of the diameter and velocity were not only unimodal, but also somewhat positively skewed and not normal.
Temporal distribution of favourite books, movies, and records: differential encoding and re- sampling. The reminiscence bump is the effect that people recall more personal events from early adulthood than from childhood or adulthood. The bump has been examined extensively.
However, the question of whether the bump is caused by differential encoding or re- sampling is still unanswered. To examine this issue, participants were asked to name their three favourite books, movies, and records.
Furthermore,they were asked when they first encountered them. We compared the temporal distributions and found that they all showed recency effects and reminiscence bumps. The distribution of favourite books had the largest recency effect and the distribution of favourite records had the largest reminiscence bump.
We can explain these results by the difference in rehearsal. Books are read two or three times, movies are watched more frequently, whereas records are listened to numerous times. The results suggest that differential encoding initially causes the reminiscence bump and that re- sampling increases the bump further. Chronic daily headache with analgesics overuse in professional women breath-hold divers.
The object of this study is to investigate the prevalence and characteristics of headache in Korean professional women breath-hold divers, including their overuse of analgesics. Headache is a common problem encountered in clinical practice, and undersea divers exhibit unique causes of headache in addition to other common primary headaches. Many scuba divers are known to use various types of drugs to overcome dive-related symptoms or to enhance their underwater performance.
The target population of this study was women divers in the northern district of Jeju Island who were registered in the divers' union. Data were collected using telephone interviews with a structured questionnaire. Headache was diagnosed and classified according to criteria of the International Headache Society.
Nine hundred and eleven The prevalence rates of headache were One hundred and four divers Overuse of combination analgesics was reported by Women divers with CDH were significantly older and they complained more of tinnitus and dizziness, and had a greater history of hypertension than divers without headache.
The prevalence of CDH is high in Korean professional women breath-hold divers, with many of them being combination-analgesics overusers. Decompression sickness in breath-hold diving, and its probable connection to the growth and dissolution of small arterial gas emboli.
We solved the Laplace equation for the radius of an arterial gas embolism AGE , during and after breath-hold diving. We used a simple three-region diffusion model for the AGE, and applied our results to two types of breath-hold dives: single, very deep competitive-level dives and repetitive shallower breath-hold dives similar to those carried out by indigenous commercial pearl divers in the South Pacific.
Because of the effect of surface tension, AGEs tend to dissolve in arterial blood when arteries remote from supersaturated tissue. However if, before fully dissolving, they reach the capillary beds that perfuse the brain and the inner ear, they may become inflated with inert gas that is transferred into them from these contiguous temporarily supersaturated tissues. By using simple kinetic models of cerebral and inner ear tissue, the nitrogen tissue partial pressures during and after the dive s were determined.
These were used to theoretically calculate AGE growth and dissolution curves for AGEs lodged in capillaries of the brain and inner ear. From these curves it was found that both cerebral and inner ear decompression sickness are expected to occur occasionally in single competitive-level dives. Our predictions both for single competitive-level and repetitive commercial breath-hold diving were consistent with what is known about the incidence of cerebral and inner ear decompression sickness in these forms of diving.
Inter- and intraobserver agreement of ADC measurements of lung cancer in free breathing, breath-hold and respiratory triggered diffusion-weighted MRI. To prospectively evaluate the inter- and intraobserver agreement of apparent diffusion coefficient ADC measurements in free breathing, breath-hold , and respiratory triggered diffusion-weighted imaging DWI of lung cancer. Lesion ADCs were measured twice by both of the two independent observers and compared.
Great inter- and intraobserver agreement was shown. According to statistical analyses of the multiplicity functions, we conclude in two volume-limited Main galaxy samples : small stellar velocity dispersion galaxies preferentially form isolated galaxies, close pairs and small group, while large stellar velocity dispersion galaxies preferentially inhabit the dense groups and clusters.
A comprehensive study of sampling -based optimum signal detection in concentration- encoded molecular communication. In this paper, a comprehensive analysis of the sampling -based optimum signal detection in ideal i. Information is encoded by modulating the amplitude of the transmission rate of information molecules at the TN.
The critical issues involved in the sampling -based receiver thus developed are addressed in detail, and its performance in terms of the number of samples per symbol, communication range, and transmission data rate is evaluated.
In addition, the performance of the optimum receiver depends on the receiver's ability to compute the ISI accurately, thus providing a trade-off between receiver complexity and achievable bit error rate BER. Exact and approximate detection performances have been derived. Dive-related injuries are relatively common, but almost exclusively occur in recreational or scuba diving. We report 2 children with acute central nervous system complications after breath-hold diving.
After ascent, he suddenly felt extreme thoracic pain that resolved spontaneously. Neurologic examination revealed right leg weakness and sensory deficits with a sensory level at T5. A few weeks later, a year-old girl was admitted with acute dizziness, personality changes, confusion, and headache. After stepping out, she felt sudden severe thoracic pain and lost consciousness.
Shortly later she reported headache and vertigo, and numbness of the complete left side of her body. Neurologic examination revealed reduced sensibility to all modalities, a positive Romberg test, and vertigo. Cerebral MRI revealed no pathologic findings. Both children experienced a strikingly similar clinical course.
The chronology of events strongly suggests that both patients were suffering from arterial gas embolism. This condition has been reported for the first time to occur in children after breath-hold diving beneath the water surface without glossopharyngeal insufflation.
Scalable boson sampling with time-bin encoding using a loop-based architecture. We present an architecture for arbitrarily scalable boson sampling using two nested fiber loops. The architecture has fixed experimental complexity, irrespective of the size of the desired interferometer, whose scale is limited only by fiber and switch loss rates. The architecture employs time-bin encoding , whereby the incident photons form a pulse train, which enters the loops.
Dynamically controlled loop coupling ratios allow the construction of the arbitrary linear optics interferometers required for boson sampling. The architecture employs only a single point of interference and may thus be easier to stabilize than other approaches.
The scheme has polynomial complexity and could be realized using demonstrated present-day technologies. MR angiography of the renal artery: comparison of breath-hold two-dimensional phase-contrast cine technique with the phased-array coil and breath-hold two-dimensional time-of-flight technique with the body coil. A PC technique with k-space segmentation was utilized with the phased-array coil.
With cardiac triggering, distal renal arteries were well demonstrated in PC MR angiography. On PC images, up- or downward movements of the mid to distal renal arteries with aortic pulsatility were recognized. The mid to distal portions of the renal arteries translationally move with aortic pulsatility. To consistently visualize and evaluate them on MR angiography, cardiac triggering might be required to reduce the effects of pulsatile motions of the renal artery in the use of a phased-array coil.
Potential, velocity , and density fields from sparse and noisy redshift-distance samples - Method. A method for recovering the three-dimensional potential, velocity , and density fields from large-scale redshift-distance samples is described.
Galaxies are taken as tracers of the velocity field, not of the mass. The density field and the initial conditions are calculated using an iterative procedure that applies the no-vorticity assumption at an initial time and uses the Zel'dovich approximation to relate initial and final positions of particles on a grid. The method is tested using a cosmological N-body simulation 'observed' at the positions of real galaxies in a redshift-distance sample , taking into account their distance measurement errors.
Malmquist bias and other systematic and statistical errors are extensively explored using both analytical techniques and Monte Carlo simulations. These calibrations were established for axial single-slice breath-hold imaging at the location of the portal vein. Scanning in multi-slice mode makes the exam more efficient, since whole-liver coverage can be achieved with two breath-holds and the optimal slice can be selected afterward.
Navigator echoes remove the need for breath-holds and allow use in sedated patients. Bland-Altman analysis showed that all imaging method comparisons were strongly associated with each other and had high correlation coefficients 0. Linear regression yielded slopes that were close to 1. We conclude that these three R2. Corrected tetralogy of Fallot: comparison of tissue doppler imaging and velocity-encoded MR for assessment of performance and temporal activation of right ventricle.
To compare velocity-encoded VE magnetic resonance MR imaging with tissue Doppler imaging to assess right ventricular RV peak systolic velocities and timing of velocities in patients with corrected tetralogy of Fallot and healthy subjects.
Local institutional review board approval was obtained; patients or their parents gave informed consent. Thirty-three patients 20 male, 13 female; median age, 12 years; interquartile range [IQR], years; age range, years and 19 control subjects 12 male, seven female; median age, 14 years; IQR, years; age range, years underwent VE MR imaging and tissue Doppler imaging.
Data were analyzed by using linear regression, paired and unpaired tests, and Bland-Altman plots. Good correlation and agreement between the two techniques were observed. Both techniques can be used interchangeably to clinically assess velocities and timing of velocities of. Cardiac changes induced by immersion and breath-hold diving in humans. To evaluate the separate cardiovascular response to body immersion and increased environmental pressure during diving, 12 healthy male subjects mean age Heart rate, left ventricular volumes, stroke volume, and cardiac output were obtained by underwater echocardiography.
Dueck, Jenny, E-mail: jenny. Purpose: The safe clinical implementation of pencil beam scanning PBS proton therapy for lung tumors is complicated by the delivery uncertainties caused by breathing motion. The purpose of this feasibility study was to investigate whether a voluntary breath-hold technique could limit the delivery uncertainties resulting from interfractional motion.
Methods and Materials: Data from 15 patients with peripheral lung tumors previously treated with stereotactic radiation therapy were included in this study. The patients had 1 computed tomographic CT scan in voluntary breath-hold acquired before treatment and 3 scans during the treatment course.
PBS proton treatment plans with 2 fields 2F andmore » 3 fields 3F , respectively, were calculated based on the planning CT scan and subsequently recalculated on the 3 repeated CT scans. Conclusions: The breath-hold approach is a realistic clinical option for treating lung tumors with PBS proton therapy.
On the basis of these results, the baseline shift of the tumor should be monitored eg, through image guided therapy , and appropriate measures should be taken accordingly. The intrafractional motion needs to be investigated to confirm that the breath-hold approach is robust. The first major huddle to the study was to determine the effect of the overnight shipping of the viability of. Breath-hold times in air compared to breath-hold times during cold water immersions.
The exercise was designed to provide firsth and experience of the effects of cold water exposure on BH time. The first BH was completed while standing on the pool deck. There were 40 of the volunteers who also breathed from an emergency breathing system EBS while in the cold water. Results demonstrated that BH capabilities in cold water were significantly lower than those in ambient air.
A significant correlation was also found between BH in air and the difference in cold water vs. The BH times for this group were similar to those reported in previous cold water immersion studies. Based on the questionnaire results, it is possible, when carefully applied, to include a practical cold water immersion exercise into existing HUET programs. DNA- encoded chemistry: enabling the deeper sampling of chemical space.
DNA- encoded chemical library technologies are increasingly being adopted in drug discovery for hit and lead generation. Franco Bontempi , Konstantinos Gkoumas. This paper focuses on the different conceptual frameworks that govern the structural problem and provides an insight on the results obtained from structural analysis, towards a sound framework for structural design. The interdisciplinary of many aspects is highlighted, considering the developments on the sustainable development and the architectonic design, and the availability of modern technologies that nowadays are integrated in the structural forms.
The paper provides significant concepts and case studies long span bridges, offshore wind turbines, high-rise buildings etc. Carlo Pellegrino. Sadeq Sinan. Log in with Facebook Log in with Google.
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