In Situ Observation of Nonpolar to Strongly Polar Atom-Ion Collision Dynamics.

The onset of collision dynamics between an ion and a Rydberg atom is studied in a regime characterized by a multitude of collision channels. These channels arise from coupling between a nonpolar Rydberg state and numerous highly polar Stark states. The interaction potentials formed by the polar Stark states show a substantial difference in spatial gradient compared to the nonpolar state leading to a separation of collisional timescales, which is observed in situ. For collision energies in the range of k_{B}µK to k_{B}K, the dynamics exhibit a counterintuitive dependence on temperature, resulting in faster collision dynamics for cold-initially "slow"-systems. Dipole selection rules enable us to prepare the collision pair on the nonpolar potential in a highly controlled manner, which determines occupation of the collision channels. The experimental observations are supported by semiclassical simulations, which model the pair state evolution and provide evidence for tunable nonadiabatic dynamics.

Rydberg Molecules for Ion-Atom Scattering in the Ultracold Regime.

We propose a novel experimental method to extend the investigation of ion-atom collisions from the so far studied cold, essentially classical regime to the ultracold, quantum regime. The key aspect of this method is the use of Rydberg molecules to initialize the ultracold ion-atom scattering event. We exemplify the proposed method with the lithium ion-atom system, for which we present simulations of how the initial Rydberg molecule wave function, freed by photoionization, evolves in the presence of the ion-atom scattering potential. We predict bounds for the ion-atom scattering length from ab initio calculations of the interaction potential. We demonstrate that, in the predicted bounds, the scattering length can be experimentally determined from the velocity of the scattered wave packet in the case of ^{6}Li^{+}-^{6}Li and from the molecular ion fraction in the case of ^{7}Li^{+}-^{7}Li. The proposed method to utilize Rydberg molecules for ultracold ion-atom scattering, here particularized for the lithium ion-atom system, is readily applicable to other ion-atom systems as well.

Observation of Rydberg Blockade Induced by a Single Ion.

We study the long-range interaction of a single ion with a highly excited ultracold Rydberg atom and report on the direct observation of an ion-induced Rydberg excitation blockade mediated over tens of micrometer distances. Our hybrid ion-atom system is directly produced from an ultracold atomic ensemble via near-threshold photoionization of a single Rydberg excitation, employing a two-photon scheme that is specifically suited for generating a very low-energy ion. The ion's motion is precisely controlled by small electric fields, which allows us to analyze the blockade mechanism for a range of principal quantum numbers. Finally, we explore the capability of the ion as a high-sensitivity, single-atom-based electric field sensor. The observed ion-Rydberg-atom interaction is of current interest for entanglement generation or studies of ultracold chemistry in hybrid ion-atom systems.

Applicability of two methods of mixed dentition analysis in a contemporary Indian population sample.

AIM: More than 10 years experience in implementing the Tanaka Johnston and Moyers methods has shown that they overestimate the sizes of unerupted canines and premolars when used in populations other than the Caucasian. This study was designed to assess the applicability of the two most commonly used methods of mixed dentition analysis and to attempt to derive a more accurate and precise formula to predict the sizes of the unerupted premolars and canines in a sample of Indian population. MATERIALS AND METHODS: The sample included 200 study models (100 male, 100 female). Tanaka Johnston's and Moyer's equations were applied to this sample and the mean differences between the actual and estimated tooth widths were determined. New regression equations were derived using lower first molars and incisors as the predictors. RESULTS: The mean difference between the actual and estimated values of canines and premolars using Tanaka Johnston's and Moyers methods were clinically and statistically significant. Therefore new regression equations were derived taking lower first molars and incisors as the predictors for both sexes. On validation, these equations were found to be accurate and precise for this population. CONCLUSION: It is recommended to use these equations as a method of mixed dentition analysis for the Indian population.

Psychogenic non-epileptic seizures, anticipatory grief and limited access to medical care.

Psychogenic non-epileptic seizures (PNES) in the context of meningoencephalitis can occur with sufficient stressors. Video-EEG is a critical diagnostic tool in such complex cases. Once the diagnosis of PNES is confirmed by video-EEG, psychiatric consultation with psychotherapeutic intervention to address underlying psychopathology and specific stressors that led to these conversion symptoms is required. Clinicians need to understand the importance of cultural themes, including the economics of healthcare, and anticipatory grief as causative stressors in pseudoseizures.

Assessment of systolic and diastolic function in clinically healthy horses using ambulatory acoustic cardiography.

BACKGROUND: Assessment of cardiac electromechanical function in horses requires training, experience and specialised equipment and does not allow continuous monitoring over time. OBJECTIVES: The objective of this study was to establish the use of an acoustic ECG monitor (Audicor® ) in healthy horses. It provides noninvasive, examiner-independent, continuous analyses combining ECG and phonocardiography to calculate indices of cardiac mechanical activity and haemodynamics. Device usability was investigated, reference intervals calculated and reproducibility of analyses assessed. STUDY DESIGN: Prospective descriptive study. METHODS: Continuous overnight recordings were obtained in 123 healthy horses. ECG and acoustic cardiography analyses were performed. Electromechanical activating time (EMAT), rate-corrected EMATc, left ventricular systolic time (LVST), rate-corrected LVSTc and intensity and persistence of the third and fourth heart sound (S3, S4) were reported. Associations with age and reproducibility of analyses were assessed. RESULTS: Audicor® recordings of diagnostic quality were obtained in 116 horses, with an artefact-free recording time of 1:08-14:03 h (mean 10:21 h). 44.8% of the horses had atrial premature complexes (up to 0.18% of analysed beats), 4.3% had ventricular premature complexes (up to 0.021% of analysed beats). Reference intervals for acoustic cardiography variables were reported. S3 was significantly more often graded ≥5 (scale 0-10) in younger compared to older horses (P = 0.0036, R2  = 0.072). The between-day coefficient of variation ranged from 2.5 to 7.7% for EMAT, EMATc, LVST and LVSTc. MAIN LIMITATIONS: Audicor® algorithms are based on human databases. Horses were deemed clinically healthy without advanced diagnostics. Some data were lost because of technical difficulties, artefacts and noises. CONCLUSIONS: Overnight Audicor® recordings are feasible in horses. Combining ambulatory ECG and phonocardiography allows noninvasive, continuous assessment of variables representing systolic and diastolic cardiac function. ECG rhythm analyses require over-reading by a specialist, but acoustic cardiography variables are based on automated algorithms independent of examiner input. Further studies are required to establish the clinical value of acoustic cardiography in horses.

Improving Radiation Awareness and Feeling of Personal Security of Non-Radiological Medical Staff by Implementing a Traffic Light System in Computed Tomography.

PURPOSE: Non-radiological medical professionals often need to remain in the scanning room during computed tomography (CT) examinations to supervise patients in critical condition. Independent of protective devices, their position significantly influences the radiation dose they receive. The purpose of this study was to assess if a traffic light system indicating areas of different radiation exposure improves non-radiological medical staff's radiation awareness and feeling of personal security. MATERIAL AND METHODS: Phantom measurements were performed to define areas of different dose rates and colored stickers were applied on the floor according to a traffic light system: green = lowest, orange = intermediate, and red = highest possible radiation exposure. Non-radiological medical professionals with different years of working experience evaluated the system using a structured questionnaire. Kruskal-Wallis and Spearman's correlation test were applied for statistical analysis. RESULTS: Fifty-six subjects (30 physicians, 26 nursing staff) took part in this prospective study. Overall rating of the system was very good, and almost all professionals tried to stand in the green stickers during the scan. The system significantly increased radiation awareness and feeling of personal protection particularly in staff with ≤ 5 years of working experience (p < 0.05). The majority of non-radiological medical professionals stated that staying in the green stickers and patient care would be compatible. Knowledge of radiation protection was poor in all groups, especially among entry-level employees (p < 0.05). CONCLUSION: A traffic light system in the CT scanning room indicating areas with lowest, intermediate, and highest possible radiation exposure is much appreciated. It increases radiation awareness, improves the sense of personal radiation protection, and may support endeavors to lower occupational radiation exposure, although the best radiation protection always is to re-main outside the CT room during the scan. KEY POINTS: • A traffic light system indicating areas with different radiation exposure within the computed tomography scanner room is much appreciated by non-radiological medical staff. • The traffic light system increases non-radiological medical staff's radiation awareness and feeling of personal protection. • Knowledge on radiation protection was poor in non-radiological medical staff, especially in those with few working experience.

Implementation of Dose Monitoring Software in the Clinical Routine: First Experiences.

PURPOSE: Radiation exposure of the public as a result of medical imaging has significantly increased during the last decades. To have a tool to register and control patient dose exposure, we implemented dose monitoring software at our institution and first connected our computed tomography (CT) scanners. MATERIALS AND METHODS: CT dose data from July 2014 to February 2015 was retrospectively analyzed using dose monitoring software. We evaluated a number of scans above predefined dose thresholds ("alerts"), assessed reasons for alerts and compared data of two CT scanners, one located close to the emergency room ("emergency CT scanner") and one mainly used on an outpatient basis ("clinical routine CT scanner"). To check for statistically significant differences between scanners, chi-square-tests were performed. RESULTS: A total of 8883 scans were acquired (clinical routine CT scanner, n = 3415; emergency CT scanner, n = 5468) during which 316 alerts were encountered (alert quota, 4 %). The overall alert quota ranged from 2 - 5 % with significantly higher values for the clinical routine CT scanner. Reasons for alerts were high BMI (51 %), patient off-centering (24 %), scan repetition (11 %), orthopedic hardware (9 %), or other (5 %). Scan repetition was necessary significantly more often with the emergency CT scanner (p = 0.019), while high BMI, off-centering and orthopedic hardware were more frequently seen with the clinical routine CT scanner (for all, p < 0.05). There was a good correlation between high body weight and dose above threshold (r = 0.585). CONCLUSION: Implementation of dose monitoring software in the clinical routine was successfully accomplished and provides important information regarding patient radiation protection. KEY POINTS: ∙ Implementation of dose monitoring software in the clinical routine can be successfully accomplished. · Dose notifications are due to human error or patient-specific factors. · Dose monitoring software provides important information regarding radiation protection of patients.

Devices for the control of laser transmission across the sclera during transscleral photocoagulation.

Improving the reproducibility of transscleral photocoagulation necessitates controlling the transmission of the laser beam through the sclera. Two factors make such control problematic: the locally increased transparency of the sclera resulting from the contact procedure and the occurrence of time-related relaxation phenomena. Two instruments have been devised to help control these factors. The first is a mechanical compensation unit comprised of magnets and a spring that allows the force exerted on the sclera to be adjusted to between 0.1 and 0.4 N, the pressure being determined by the outer diameter of the contact tip. The second instrument monitors the portion of the aiming beam reflected by the sclera as a means of determining the exact level of power actually transmitted through it. This information theoretically could be fed back to the treatment laser, allowing the level of power being delivered to be adjusted accordingly.