Relative phase effect of nonsequential double ionization of molecules by counter-rotating two-color circularly polarized fields.

Relative phase effect of nonsequential double ionization (NSDI) of aligned molecules by counter-rotating two-color circularly polarized (TCCP) fields is investigated with a three-dimensional classical ensemble model. Numerical results show that NSDI yield in counter-rotating TCCP fields sensitively depends on the relative phase of the two components, which exhibits a sin-like behavior with the period of π/2. NSDI yield achieves its maximum at the relative phase π/8 and minimum at 3π/8. Back analysis indicates the recollision time and the return angle of the electron strongly depend on the relative phase of the two components, which results in the dominant emission direction of the electrons, is different for different relative phases. This indicates that the recollision process can be steered by changing the relative phase of the two components in counter-rotating TCCP laser fields. Meantime, it provides an avenue to obtain information about the recollision time and the return angle in the recollision process from the electron momentum distribution.

The Development of a Macromolecular Analgesic for Arthritic Pain.

The addictive potential of clinically used opioids as a result of their direct action on the dopaminergic reward system in the brain has limited their application. In an attempt to reduce negative side effects as well as to improve the overall effectiveness of these analgesics, we have designed, synthesized, and evaluated an N-(2-hydroxypropyl)methacrylamide (HPMA)-based macromolecular prodrug of hydromorphone (HMP), a commonly used opioid. To this end, P-HMP was synthesized via RAFT polymerization and a subsequent polymer analogous reaction. Its interaction with inflammatory cells in arthritic joints was evaluated in vitro using a RAW 264.7 cell culture, and subsequent confocal microscopy analysis confirmed that P-HMP could be internalized by the cells via endocytosis. In vivo imaging studies indicated that the prodrug can passively target the arthritic joint after systemic administration in a rodent model of monoarticular adjuvant-induced arthritis (MAA). The inflammatory pain-alleviating properties of the prodrug were assessed in MAA rats using the incapacitance test and were observed to be similar to dose-equivalent HMP. Analgesia through mechanisms at the spinal cord level was further measured using the tail flick test, and it was determined that the prodrug significantly reduced spinal cord analgesia versus free HMP, further validating the peripheral restriction of the macromolecular prodrug. Immunohistochemical analysis of cellular uptake of the P-HMP within the MAA knee joint proved the internalization of the prodrug by phagocytic synoviocytes, colocalized with HMP's target receptor as well as with pain-modulating ion channels. Therefore, it can be concluded that the novel inflammation-targeting polymeric prodrug of HMP (P-HMP) has the potential to be developed as an effective and safe analgesic agent for musculoskeletal pain.

Performance comparison of laryngoscopy and suction techniques in a hemorrhagic airway manikin simulator: direct laryngoscopy with Yankauer vs. Storz CMAC with attached suction tip.

Airway management of the hemorrhagic airway can be a difficult skill to master as trainee exposure to this difficult airway may be limited. In this study, we employed a hemorrhagic airway simulator along with a videolaryngoscope and the Storz Boedker-Doerges (BD) suction blade. These devices provided improved intubation performance in this model with respect to traditional direct laryngoscope (DL) and VL blades. This study shows that use of a hemorrhagic simulator could be an effective and valuable training tool in difficult airway intubation training.

Periocular Manifestation of Obstructive Sleep Apnea as a Novel Perioperative Screening Tool.

PURPOSE: Obstructive sleep apnea (OSA) presents perioperative challenges with increased risk for complications. Floppy eyelid syndrome (FES) is associated with OSA yet has not been addressed perioperatively. The current standard for perioperative OSA screening includes assessing patient risk factors or the STOP-BANG tool, which requires an active participant. We aimed to confirm a connection between FES and OSA in presurgical patients and develop a screening method appropriate for patients with perioperative OSA risk. MATERIALS AND METHODS: 162 presurgical pre-anesthesia clinic patients were enrolled. Screening questions determined eligibility. Those who were pregnant or aged < 19 were excluded. Control group included those with a STOP-BANG score < 3. Experimental group included those with BMI > 35 and OSA diagnosis. Examiners photographed participants' eyes with vertical and horizontal retraction while two blinded ophthalmologists used a grading scale to review grade of eyelid laxity. RESULTS: Differences in habitus, ASA score, and hypertension as a comorbidity were significant. Sensitivity of FES screening was 52% (CI 37-66%) and specificity was 56% (CI 46-66%) for reviewer 1. For reviewer 2, sensitivity was 48% (CI 28-69%) and specificity was 72% (CI 60-81%). Negative predictive value was 86% (CI 81-90) for reviewer 1 and 88% (CI 83-92%) for reviewer 2. Inter-rater agreement was moderate. CONCLUSION: While specificity and sensitivity were lower than anticipated, negative predictive value was high. Given this strong negative predictive value, our findings indicate using eyelid retraction to screen for FES has perioperative clinical utility. These findings encourage further research addressing the connection of lid laxity/FES to OSA. KEY POINTS: • Aimed to investigate if a FES screening tool could identify perioperative OSA risk. • Negative predictive value for FES with OSA was 86%. • Observing periocular lid laxity has clinical utility; is feasible in any patient.

Prospective Randomized Evaluation of Preoperative Angiotensin-Converting Enzyme Inhibition (PREOP-ACEI).

BACKGROUND: Intraoperative hypotension is associated with an increased risk of end organ damage and death. The transient preoperative interruption of angiotensinconverting enzyme inhibitor (ACEI) therapy prior to cardiac and vascular surgeries decreases the occurrence of intraoperative hypotension. OBJECTIVE: We sought to compare the effect of two protocols for preoperative ACEI management on the risk of intraoperative hypotension among patients undergoing noncardiac, nonvascular surgeries. DESIGN: Prospective, randomized study. SETTING: Midwestern urban 489-bed academic medical center. PATIENTS: Patients taking an ACEI for at least six weeks preoperatively were considered for inclusion. INTERVENTIONS: Randomization of the final preoperative ACEI dose to omission (n = 137) or continuation (n = 138). MEASUREMENTS: The primary outcome was intraoperative hypotension, which was defined as any systolic blood pressure (SBP) < 80 mm Hg. Postoperative hypotensive (SBP < 90 mm Hg) and hypertensive (SBP >> 180 mm Hg) episodes were also recorded. Outcomes were compared using Fisher's exact test. RESULTS: Intraoperative hypotension occurred less frequently in the omission group (76 of 137 [55%]) than in the continuation group (95 of 138 [69%]) (RR: 0.81, 95% CI: 0.67 to 0.97, P = .03, NNH 7.5). Postoperative hypotensive events were also less frequent in the ACEI omission group (RR: 0.49, 95% CI: 0.28 to 0.86, P = .02) than in the continuation group. However, postoperative hypertensive events were more frequent in the omission group than in the continuation group (RR: 1.95, 95%: CI: 1.14 to 3.34, P = .01). CONCLUSIONS: The transient preoperative interruption of ACEI therapy is associated with a decreased risk of intraoperative hypotension. REGISTRATION: ClinicalTrials.gov: NCT01669434.

[Impacts of pH and surfactants on adsorption behaviors of norfloxacin on marine sediments].

The adsorption behaviors of norfloxacin (NOR) on marine sediments at different pH values and in the presence of four different surfactants were systematically investigated by a batch equilibrium method. The results indicated that Freundlich adsorption isotherms fitted the adsorption behavior of NOR on marine sediments very well at different pH values. The Freundlich constant K(F) and the equilibrium adsorption amount of NOR reduced with the increase of pH values, and the minimum appeared at pH 8.10. The results suggested that cation exchange was the main adsorption mechanism of NOR at pH 6.01, while Van der Waals' force, hydrophobic effects, electrostatic force were the major adsorption mechanism of NOR on marine sediments at pH 8.10. The adsorption process fitted well with pseudo-second-order kinetic equations with the addition of surfactants. Our study also indicated that the addition of surfactants had the significant influence on the saturated adsorption amount of adsorption of NOR. The equilibrium adsorption amount (Q(e)) of NOR exhibited the following sequence: Q(e) (Tween80) < Q(e) (Tween20)

Pilot study to determine the utility of point-of-care ultrasound in the assessment of difficult laryngoscopy.

OBJECTIVES: Prediction of difficult laryngoscopy in emergency care settings is challenging. The preintubation clinical screening tests may not be applied in a large number of emergency intubations due to the patient's clinical condition. The objectives of this study were 1) to determine the utility of sonographic measurements of thickness of the tongue, anterior neck soft tissue at the level of the hyoid bone, and thyrohyoid membrane in distinguishing difficult and easy laryngoscopies and 2) to examine the association between sonographic measurements (thickness of tongue and anterior neck soft tissue) and difficult airway clinical screening tests (modified Mallampati score, thyromental distance, and interincisor gap). METHODS: This was a prospective observational study at an academic medical center. Adult patients undergoing endotracheal intubation for an elective surgical procedure were included. The investigators involved in data collection were blinded to each other's assessments. Demographic variables were collected preoperatively. The clinical screening tests to predict a difficult airway were performed. The ultrasound (US) measurements of tongue and anterior neck soft tissue were obtained. The laryngoscopic view was graded using Cormack and Lehane classification by anesthesia providers on the day of surgery. To allow for comparisons between difficult airway and easy airway groups, a two-sided Student's t-test and Fisher's exact test were employed as appropriate. Spearman's rank correlation coefficients were used to examine the association between screening tests and sonographic measurements. RESULTS: The mean (±standard deviation [SD]) age of 51 eligible patients (32 female, 19 male) was 53.1 (±13.2) years. Six of the 51 patients (12%, 95% confidence interval [CI] = 3% to 20%) were classified as having difficult laryngoscopy by anesthesia providers. The distribution of laryngoscopy grades for all subjects was 63, 25, 4, and 8% for grades 1, 2, 3, and 4, respectively. In this study, 83% of subjects with difficult airways were males. No other significant differences were noted in the demographic variables and difficult airway clinical screening tests between the two groups. The sonographic measurements of anterior neck soft tissue were greater in the difficult laryngoscopy group compared to the easy laryngoscopy group at the level of the hyoid bone (1.69, 95% CI = 1.19 to 2.19 vs. 1.37, 95% CI = 1.27 to 1.46) and thyrohyoid membrane (3.47, 95% CI = 2.88 to 4.07 vs. 2.37, 95% CI = 2.29 to 2.44). No significant correlation was found between sonographic measurements and clinical screening tests. CONCLUSIONS: This pilot study demonstrated that sonographic measurements of anterior neck soft tissue thickness at the level of hyoid bone and thyrohyoid membrane can be used to distinguish difficult and easy laryngoscopies. Clinical screening tests did not correlate with US measurements, and US was able to detect difficult laryngoscopy, indicating the limitations of the conventional screening tests for predicting difficult laryngoscopy.