The relaxation dynamics of vibrationally excited ground-state azulene molecules have been examined by picosecond transient absorption spectroscopy in a variety of different solvents including hexane, chloromethanes, methanol, CClF3, Xe, and Kr. A high pressure optical cell was used to liquify gases for use as solvents and to change their density and temperature independently over the entire liquid density range. Experimental results indicate that the vibrational cooling rate is strongly solvent dependent, with cooling rates of approximately 20 ps in molecular solvents and approximately 150 ps in atomic solvents. Comparison of the rates in Xe and Kr at constant number density demonstrates the strong effect of solvent mass on energy transfer. The effect of solvent temperature on vibrational cooling is minimal, as is the effect of solvent density. The latter result is quite surprising in light of earlier experiments on simpler molecular systems, such as I2 in Xe, and predictions of isolated binary collision theories. An explanation is offered from large scale molecular dynamics simulations of the system. In effect, azulene forms an ‘‘ordered Xe cluster’’ with xenon atoms; the xenon number density normal to the azulene molecular plane is independent of solvent density.
Background: Arrhythmias are a leading cause of death in adults with congenital heart disease (ACHD). While 24-48-hour monitors are often used to assess arrhythmia burden, extended continuous ambulatory rhythm monitors (ECAM) can record 2 weeks of data. The utility of this device and the arrhythmia burden identified beyond 48-hour monitoring have not been evaluated in the ACHD population. Additionally, the impact of ECAM has not been studied to determine management recommendations.Objective: To address the preliminary question, we hypothesized that clinically significant arrhythmias would be detected on ECAM beyond 48 hours and this would lead to clinical management changes. Methods:A single center retrospective cohort study of ACHD patients undergoing ECAM from June 2013 to May 2016 was performed. The number and type of arrhythmias detected within and beyond the first 48 hours of monitoring were compared using Kaplan-Meier curves and Cox proportional hazard models. Results: Three hundred fourteen patients had monitors performed [median age 31(IQR 25-41) years, 61% female). Significant arrhythmias were identified in 156 patients (50%), of which 46% were noted within 48 hours. A management change based on an arrhythmia was made in 49 patients (16%).Conclusions: ECAM detects more clinically significant arrhythmias than standard 48hour monitoring in ACHD patients. Management changes, including medication changes, further testing or imaging, and procedures, were made based on results of ECAM. Recommendations and guidelines have been made based on arrhythmias on 48-hour monitoring; the predictive ability and clinical consequence of arrhythmias found on ECAM are not yet known.
Background Managing "spaghetti syndrome," the tangle of therapeutic cables, tubes, and cords at patients' bedsides, can be challenging. oBjectives To assess nurses' perceptions of the effectiveness of a novel banding device in management of spaghetti syndrome. Methods A simple color-coded elastomeric banding strap with ribbed flaps was attached to bed rails of adult critical care patients to help organize therapeutic cables, tubes, wires, and cords. Nurses were surveyed before and after use of the bands and after the nursing shift to assess the burden of spaghetti syndrome and the effectiveness of using the bands. results Use of the bands decreased the time spent untangling cords, reduced the frequency of contact of tubing with the floor, and diminished disruptions in care. conclusions Use of a simple flexible latex-free elastomeric band may help organize therapeutic tubing at patients' bedsides and may promote improvements in nursing care. (Critical Care Nurse. 2015;35[6]:38-45) ©2015 American Association of Critical-Care Nurses doi: http://dx.doi.org/10.4037/ccn2015321 C ritical care patients often have numerous therapeutic connections (eg, cords, cables, and tubes) at the bedside that can easily become disorganized and tangled, leading to contamination of the connections, nurses' confusion, a physical hazard that increases the risk for falls for both nurses and patients, and the possibility of damage of medical devices.1-6 This phenomenon, known as spaghetti syndrome, makes caring for patients challenging and difficult 1,2 ( Figure 1). Multiple instances of patients' deaths, permanent injury, and life-threatening situations related to entanglement with the cords of medical devices have been reported. 5,[7][8][9][10][11][12][13][14] Ensuring the organization of cords and tubes at a patient's bedside may reduce adverse outcomes such as entanglement of the patient, backflow in tubing, falls by both patients and health care personnel, and connection errors or damage of medical equipment. [5][6][7]12 38 Therapeutic tubing, cables, wires, and cords are a fundamental aspect of daily health care for delivery of medications and fl uids to patients. The often disorganized tubing and cords at the bedside increase the possibility of inadvertently connecting the wrong syringes and tubing and then unintentionally delivering medication or fl uids via the wrong route. In 2006, the Joint Commission issued alerts on tubing misconnections; interventions and procedures to manage and protect medical cords, tubes, and cables as a standard of care, but only a few devices are available to aid in this task. 11,13,15 Few bedside devices for cord control are commercially available, and they vary in complexity and design. The purpose of this study was to test use of a novel simple, sleeved-strap banding device in the management of spaghetti syndrome in a critical care unit and to assess nurses' responses to use of the band. Before the study, no devices or standard protocols were being used to manage the syndrome. MethodsAfter a compa...
activity seen for addition of DMSO parallels that observed for methanol, strongly indicating that the changes observed are again due primarily to the variation in solvent dielectric constant. DMSO has a dielectric constant (< = 47) similar to that of methanol but is devoid of hydrogen bonding. DiscussionThe conclusion drawn above, that the "dissociated" model of Schipper best fits the data for L-histidine-Tb(DPA)33", differs from that of Brittain et al., who have described the interaction of various chiral substrates including L-histidine with Ln(DPA)33" as forming 1:1 complexes.10 Our results do, however, agree with those of Schipper, who examined similar concentration data for Pfeiffer-active transition-metal systems and also concluded that the dissociated model appears to give a better fit to the experimental data than the associated model.17Although the addition of L-histidine to racemic solutions of lanthanide-DPA complexes clearly results in an equilibrium shift, exactly which enantiomer is favored has not been known until very recently. By comparison of CPL and CD spectra from an optically active crystal of Na3Eu(DPA)3-2NaC104-6H20 to that of a Pfeiffer-perturbed Eu(DPA)33" solution, we have concluded that addition of L-histidine results in an excess of the -enantiomer.19 This conclusion is in agreement with that of Brittain.11 This result implies that ( ) is negative (see eq 14, 16, and 18) and that the L-histidineinteraction, ( -), is of lower energy. A multipole-multipole calculation of this interaction is in progress.The results presented above for mixed solvent systems indicate that the chiral discriminatory interaction has a large electrostatic component. In addition, it is concluded that hydrogen-bonding effects are less important. No attempt has been made to take into account selective solvation or other complications of these mixed solvent systems,20 but such work is under way.
A 5-year-old previously healthy girl presented to the emergency department (ED) with vomiting for 6 days. Her activity level was normal but her parents described progressive exercise intolerance with frequent recreational breaks approximately 2 days prior to presentation. In addition, the child complained of mild abdominal discomfort that began 24 hours prior to her presentation. She had no diarrhea or changes in her diet or oral intake; she had no dysuria or changes in urination. She had no cough, shortness of breath, dizziness, vision changes, falls, or decreased coordination.
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