Application of Counter-wound Multi-arm Spirals in HTS Resonator Design.

Significant sensitivity improvements have been achieved by utilizing high temperature superconducting (HTS) resonators in nuclear magnetic resonance (NMR) probes. Many nuclei such as 13C benefit from strong excitation fields which cannot be produced by traditional HTS resonator designs. We investigate the use of double-sided, counter-wound multi-arm spiral HTS resonators with the aim of increasing the excitation field at the required nuclear Larmor frequency for 13C. When compared to double-sided, counter-wound spiral resonators with similar geometry, simulations indicate that the multi-arm spiral version develops a more uniform current distribution. Preliminary tests of a two-arm resonator indicate that it may produce a stronger excitation field.

Progress Towards a Higher Sensitivity 13C-Optimized 1.5 mm HTS NMR Probe.

Nuclear magnetic resonance (NMR) probes using thin-film high temperature superconducting (HTS) resonators offer high sensitivity and are particularly suitable for small-sample applications. We are developing an improved 1.5 mm HTS NMR probe designed for operation at 14.1 T and optimized for 13C detection. The total sample volume is about 35 µL and the active sample volume is 20 µL. The probe employs HTS resonators for 13C and 1H transmission and detection and the 2H lock. We examine the interactions of multiple superconducting resonators and normal metal tuning loops on coil resonance frequency and probe sensitivity. We test a recently introduced 13C resonator design, engineered to significantly increase 13C detection sensitivity over previous all-HTS probes. At zero field, we observe a 13C quality factor of 6000 which is several times higher than previous resonators. In this work the coil design considerations and probe build-out procedure are discussed.

Measurements of Ion Binding to Lipid-Hosted Ionophores by Affinity Chromatography.

The binding affinity between antibiotic ionophores and alkali ions within supported lipid bilayers was evaluated using affinity chromatography. We used zonal elution and frontal analysis methods in nanovolume liquid chromatography to characterize the binding selectivity of the carrier and channel ionophores valinomycin and gramicidin A within different phosphatidylcholine bilayers. Distinct binding sensitivity to the lipid phase, both in affinity and selectivity, is observed for valinomycin, whereas gramicidin is less sensitive to changes in a membrane environment, behavior that is consistent with ion binding occurring within the interior of an established channel. There is good agreement between the chromatographic retention and the reported binding selectivity measured by other techniques. Surface potential near the binding site affects ion retention and the apparent association binding constants, but not the binding selectivity or enthalpy measurements. A model accounting for the surface potential contributions of retained ions during frontal analyses yields values close to intrinsic binding constants for gramicidin A (KA for K+ between 70 and 120 M-1) using reasonable estimates of the initial potential that is postulated to arise from the underlying silica.

2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging: Best Practices for Safety and Effectiveness-A Review for the Cardiac Anesthesiologist.

The American College of Cardiology, in collaboration with the American Society of Nuclear Cardiology, Heart Rhythm Society, Mended Hearts, North American Society for Cardiovascular Imaging, Society for Cardiovascular Angiography and Interventions, Society for Cardiovascular Computed Tomography, and Society of Nuclear Medicine and Molecular Imaging, recently published a consensus document recommending best practices for the use of ionizing radiation in cardiovascular medicine. With the increase in number and complexity of catheter-based cardiovascular interventions, cardiothoracic anesthesiologists are being requested to consult and provide care for these patients. This review summarizes the salient portions of the consensus document as it pertains to the anesthesiologist. Radiation exposure for both patients and providers should be minimized to be as low as reasonably achievable. For the anesthesiologist involved in the procedure, the authors recommend wearing protective garments including apron, vest, neck collar, and glasses of at least 0.25-mm lead or lead equivalent. The addition of a portable shield also is strongly recommended. The anesthesiologist should maintain the maximum distance allowable from the x-ray source, remembering that radiation intensity is inversely proportional to the square of the distance from the x-ray source. Monitoring radiation exposure is done best by both collar and under-apron film badge. A 0.5-mm lead-equivalent apron is expected to shield approximately 95% of the radiation. By using these recommendations, the anesthesiologist should be able to keep radiation exposure under 20 mSv per year as recommended by the International Commission on Radiation Protection.

Nursing values and moral identity in baccalaureate nursing students.

BACKGROUND: Professional nursing identity formation requires alignment with the values and moral norms of the nursing profession. PURPOSE: This study sought to explore professional nursing identity formation by comparing differences in nursing values and moral identity between students enrolled in generic Bachelor of Science in nursing (BS) programs and Accelerated Second-degree Bachelor of Science in nursing (ASBS) programs who were nearing graduation. Secondary aims were 1) to explore the relationship between nursing values and moral identity and, 2) to analyze the influence of moral identity and being in an ASBS program on nursing values in baccalaureate students." METHODS: The descriptive, correlative study used a 42-item survey that included the Nursing Professional Values Scale-3 (NPVS-3), the Moral Identity Scale (MIS), and four demographic questions. An emailed invitation to take the online survey was distributed to senior students enrolled at four universities in California. RESULTS: No significant differences in NPV-3 scores or MIS scores between BS students and ASBS students were found. Overall, students scored lowest in the NPV-3 activism subfactor. A positive, statistically significant relationship between nursing values and moral identity was revealed. Regression modeling detected that every 1-point increase on the MIS significantly corresponded to an increase of 1.26 points on the NPVS-3 after adjusting for age and gender. Enrollment in an ASBS program did not have a statistically significant influence on nursing values. CONCLUSIONS: Findings suggest that students in both BS and ASBS programs who are nearing graduation are fully engaging with being a nurse. Overall, students ascribe more importance to the NPVS-3 subfactor of caring, and less importance on the NPVS-3 subfactors of activism and professionalism. Nursing values as measured by the NPVS-3 and moral identity as measured by the MIS are distinct concepts that together provide a salient measure of Professional Nursing Identity Formation in baccalaureate students.

Burnout, Self-Efficacy, and Resilience in Haitian Nurses: A Cross-Sectional Study.

Purpose of Study: Though nursing burnout is a global problem, research on nurse burnout in Haiti is scarce. In a context of multiple personal, social, and environmental challenges, this study assessed burnout and associated factors among Haitian nurses. Design of Study: A multi-site cross-sectional study. Methods: A survey in French and Haitian Creole was conducted in five Haitian hospitals using forward and back translated scales measuring burnout (emotional exhaustion [EE], depersonalization [DP], personal accomplishment [PA]), self-efficacy, nursing work environment, resilience, and demographics. Findings: Haitian nurses (N = 179) self-reported moderate EE (M = 21, SD = 11.18), low DP (Mdn = 2.0, range = 29), and high personal accomplishment (Mdn = 41.0, range = 33). General self-efficacy (M = 32.31, SD = 4.27) and resilience (M = 26.68, SD = 5.86) were high. Dissatisfaction with salary, autonomy, and staffing were evident. Conclusions: It is noteworthy that burnout was lower than expected given the scarce resource, difficult socio-politico-economic environment. High levels of self-efficacy and resilience likely mitigated a higher level of burnout. Adaptation enables these nurses to manage their critical conditions and practice holistic nursing, which may inspire hope among nurses in similar contexts.

Hemodynamic stability during biventricular pacing after cardiopulmonary bypass.

OBJECTIVE: To assess the stability of cardiac output, mean arterial pressure, and systemic vascular resistance during biventricular pacing (BiVP) optimization. DESIGN: Substudy analysis of data collected as part of a randomized controlled study examining the effects of optimized temporary BiVP after cardiopulmonary bypass (CPB). SETTING: A single-center study at a university-affiliated tertiary care hospital. PARTICIPANTS: Cardiac surgery patients at risk of left ventricular failure after CPB. INTERVENTIONS: BiVP was optimized immediately after CPB. Atrioventricular delay (7 unique settings) was optimized first, followed by the left ventricular pacing site (3 unique settings) and then the interventricular delay (9 unique settings). Each setting was tested twice for 10 seconds each time. Vasoactive medication and fluid infusion rates were held constant. MEASUREMENTS AND MAIN RESULTS: Aortic flow velocity and radial artery pressure were digitized, recorded, and averaged over single respiratory cycles. Least squares and linear regression/Wilcoxon analyses were applied to the first 7 patients studied. Subsequently, curvilinear analysis was applied to 15 patients. Changes in mean arterial pressure and systemic vascular resistance were statistically insignificant or too small to be meaningful by least squares analysis. During interventricular synchrony optimization, cardiac output and mean arterial pressure decreased (mean changes -5.7% and -2.5%, respectively; with standard errors 2.3% and 1.5%, respectively), whereas SVR increased (mean change 3.1% with standard error 3.4%). Only the change in cardiac output was statistically significant (p = 0.043). Curvilinear fits to data for 15 patients demonstrated progressive hemodynamic stability over the total testing period. CONCLUSION: BiVP optimization may be done safely in patients after CPB. With continuous monitoring of mean arterial pressure and cardiac output, the procedure results in no harmful hemodynamic perturbation.

New near-infrared rhodamine dyes with large Stokes shifts for sensitive sensing of intracellular pH changes and fluctuations.

New near-infrared rhodamine dyes with large Stokes shifts were developed and applied for sensitive detection of cellular pH changes and fluctuations by incorporating an additional amine group with fused rings into the rhodamine dyes to enhance the electron donating ability of amine groups and improve the spectroscopic properties of the dyes.

Auditory cortical neurons respond to somatosensory stimulation.

The prevailing hierarchical model of cortical sensory processing holds that early processing is specific to individual modalities and that combination of information from different modalities is deferred until higher-order stages of processing. In this paper, we present physiological evidence of multisensory convergence at an early stage of cortical auditory processing. We used multi-neuron cluster recordings, along with a limited sample of single-unit recordings, to determine whether neurons in the macaque auditory cortex respond to cutaneous stimulation. We found coextensive cutaneous and auditory responses in caudomedial auditory cortex, an area lying adjacent to A1, and at the second stage of the auditory cortical hierarchy. Somatosensory-auditory convergence in auditory cortex may underlie effects observed in human studies. Convergence of inputs from different sensory modalities at very early stages of cortical sensory processing has important implications for both our developing understanding of multisensory processing and established views of unisensory processing.

Anesthetic implications of extended right hepatectomy in a patient with fontan physiology.

Patients who have undergone complete cavopulmonary anastomosis, the Fontan procedure, have passive venous blood flow from the superior and inferior vena cava into the pulmonary circulation without passing through the right ventricle. Although this procedure is an effective means of palliation, the resultant chronically increased central venous pressure, leads to several types of hepatic dysfunction including chronic congestion, cardiac cirrhosis, and even hepatocellular carcinoma. In this case report, we describe a patient with Fontan-associated hepatocellular carcinoma who successfully underwent a right hepatectomy.

Cardiac output measurement by arterial pressure waveform analysis during optimization of biventricular pacing after cardiac surgery.

Biventricular pacing (BiVP) can optimize cardiac output (CO) in patients after cardiac surgery, so devices that calculate continuous CO from arterial pressure may be a useful tool. We investigated PulseCO for measuring CO during optimization by comparison with aortic flow probe measurement. Seven patients in the Biventricular Pacing After Cardiac Surgery (BiPACS) trial were studied. Before weaning from cardiopulmonary bypass, BiVP was initiated. After bypass, CO was optimized by varying atrioventricular pacing delay, ventricular site, and interventricular pacing delay with a randomized protocol. Continuous CO was measured by PulseCO and aortic flow probe. Reliability was estimated by Fleiss method and agreement assessed by Bland-Altman analysis. Compared with flow probe, PulseCO reliably measured changes in CO (intraclass correlation coefficient = 0.90) but underestimated the change (-4% + or - 17%). In contrast, changes in mean arterial pressure did not reflect changes in CO (intraclass correlation coefficient = 0.02). Thus, PulseCO can measure continuous CO in open-chest patients after cardiac surgery, whereas underestimating changes occurring across 10-second pacemaker changes. Further studies in the closed chest are indicated.