Abrupt and gradual onset of synchronized oscillations due to dynamical quorum sensing in the single-cathode multi-anode nickel electrodissolution system.

The nonlinear dynamics of an oscillatory Ni electrodissolution-hydrogen ion reduction system are explored in a multi-electrode anode-single cathode system. A mathematical analysis of the charge balance equations reveals that the coupling scheme is similar to dynamical quorum sensing, where the number of anode wires affects a parameter related to the population density. In a parameter region where the large population exhibits stationary behavior, with sufficiently strong coupling (with small individual resistances attached to the anode wires), synchronized oscillations emerge abruptly with decreasing the number of anodes. Therefore, an "inverse" dynamical quorum sensing takes place. With weak coupling the transition is gradual. The experiments are supported by numerical simulation of a kinetic model of the process. The results thus show that the description of nontrivial cathode-anode interactions in the form of dynamical quorum sensing provides an efficient way of analyzing the dynamical response of complex, interacting electrochemical reactions.

Flexor Tenosynovectomy for Recurrent Carpal Tunnel Syndrome: A Retrospective Case Series of 108 Hands.

Background: The etiology of recurrent carpal tunnel syndrome (CTS) is unclear, and outcomes following secondary surgery in this demographic have been poorer than primary surgery. Fibrosis and hypertrophy have been identified in the flexor tenosynovium in these patients. The authors use flexor tenosynovectomy (FTS) for recurrent CTS after primary carpal tunnel release and present a review of these patients. Methods: A retrospective chart review was performed of 108 cases of FTS for recurrent CTS from 1995 to 2015 by 4 attending surgeons at one institution. Demographic information, symptoms, and outcomes were among the data recorded. A phone survey was conducted on available patients where the shortened version of the Disabilities of the Arm, Shoulder and Hand Questionnaire (QuickDASH) and satisfaction were assessed. Results: Average office follow-up was 12 months. Average age was 57.5 years. A total of 104 (96%) reported symptom improvement and 48 (44%) reported complete symptom resolution. Forty patients were available for long-term follow-up at an average 6.75 years postoperatively via phone interview. Average QuickDASH score was 31.2 in these patients. Thirty-six (90%) of 40 patients were initially satisfied at last office visit, and 31 (78%) of 40 were satisfied at average 6.9 years, a maintenance of satisfaction of 86%. Satisfied patients were older (58 years) than unsatisfied patients (51 years). Conclusion: Both long-term satisfaction and QuickDASH scores in our cohort are consistent with or better than published results from nerve-shielding procedures. The authors believe a decrease in both carpal tunnel volume and potential adhesions of fibrotic or inflammatory synovium contributes to the benefits of this procedure. This remains our procedure of choice for recurrent CTS.

Optimal waveform for the entrainment of a weakly forced oscillator.

A theory for obtaining a waveform for the effective entrainment of a weakly forced oscillator is presented. Phase model analysis is combined with calculus of variation to derive a waveform with which entrainment of an oscillator is achieved with a minimum power forcing signal. Optimal waveforms are calculated from the phase response curve and a solution to a balancing condition. The theory is tested in chemical entrainment experiments in which oscillations close to and farther away from a Hopf bifurcation exhibited sinusoidal and higher harmonic nontrivial optimal waveforms, respectively.

Tranexamic Acid Use in Open Reduction and Internal Fixation of Fractures of the Pelvis, Acetabulum, and Proximal Femur: A Randomized Controlled Trial.

OBJECTIVE: To assess the safety and efficacy of tranexamic acid (TXA) use in fractures of the pelvic ring, acetabulum, and proximal femur. DESIGN: Prospective, randomized controlled trial. SETTING: Single Level 1 trauma center. PATIENTS: Forty-seven patients were randomized to the study group, and 46 patients comprised the control group. INTERVENTION: The study group received 15 mg/kg IV TXA before incision and a second identical dose 3 hours after the initial dose. MAIN OUTCOME MEASUREMENTS: Transfusion rates and total blood loss (TBL) [via hemoglobin-dilution method and rates of venous thromboembolic events (VTEs)]. RESULTS: TBL was significantly higher in the control group (TXA = 952 mL, no TXA = 1325 mL, P = 0.028). The total transfusion rates between the TXA and control groups were not significantly different (TXA 1.51, no TXA = 1.17, P = 0.41). There were no significant differences between the TXA and control groups in inpatient VTE events (P = 0.57). CONCLUSION: The use of TXA in high-energy fractures of the pelvis, acetabulum, and femur significantly decreased calculated TBL but did not decrease overall transfusion rates. TXA did not increase the rate of VTE. Further study is warranted before making broad recommendations for the use of TXA in these fractures. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Dual kinetic curves in reversible electrochemical systems.

We introduce dual kinetic chronoamperometry, in which reciprocal relations are established between the kinetic curves of electrochemical reactions that start from symmetrical initial conditions. We have performed numerical and experimental studies in which the kinetic curves of the electron-transfer processes are analyzed for a reversible first order reaction. Experimental tests were done with the ferrocyanide/ferricyanide system in which the concentrations of each component could be measured separately using the platinum disk/gold ring electrode. It is shown that the proper ratio of the transient kinetic curves obtained from cathodic and anodic mass transfer limited regions give thermodynamic time invariances related to the reaction quotient of the bulk concentrations. Therefore, thermodynamic time invariances can be observed at any time using the dual kinetic curves for reversible reactions. The technique provides a unique possibility to extract the non-steady state trajectory starting from one initial condition based only on the equilibrium constant and the trajectory which starts from the symmetrical initial condition. The results could impact battery technology by predicting the concentrations and currents of the underlying non-steady state processes in a wide domain from thermodynamic principles and limited kinetic information.