The Impact of Inter-Hospital Transfer on Clinical Outcomes following Endovascular Treatment for Acute Ischemic Stroke

PURPOSE Hospitals designated as primary stroke centers offer noninvasive treatment for acute ischemic stroke, but only comprehensive stroke centers are equipped to provide endovascular treatment. When stroke patients needing endovascular treatment present to the emergency department at a primary stroke center, they then require inter-hospital transfer to a comprehensive center for definitive treatment. Recent studies have found significant treatment delays and poor clinical outcomes in patients requiring inter-hospital transfer1,2. The primary aim of this study is to determine if inter-hospital transfer impacts clinical outcomes after endovascular treatment for acute ischemic stroke. A secondary aim is to determine whether inter-hospital transfer coincides with any significant treatment delay. METHODS This study involves retrospective chart review for 107 patients undergoing endovascular treatment for acute ischemic stroke at one of three hospitals in Austin, Texas from October 2016 to September 2018. 26 patients required inter-hospital transfer, while 81 (the control group) presented directly to a hospital offering endovascular treatment. Two-tailed T- and U-tests were used for analysis of parametric and non-parametric variables pertaining to time intervals and baseline characteristics. Odds ratios were calculated to compare dichotomized outcomes between groups, with significance determined by chi-square. RESULTS Inter-hospital transfer significantly prolonged onset to groin (mean difference = 37.2 min, p=.02). The transfer group was more likely to experience intracranial hemorrhage (53.9% > 22.2%, p<.01). Clinical outcomes did not significantly differ between groups. CONCLUSIONS Although observed trends in these data suggest poor outcomes for transfer patients, small sample size limits the significance of these findings. However, the significant treatment delay seen in the transfer group warrants a discussion on city protocol changes regarding patient transport via emergency services. Protocol changes favoring direct delivery of patients to comprehensive stroke centers may reduce treatment delay and yield improved clinical outcomes.Dell Medical Schoo

Development of a Transition Between an Energy-Absorbing Concrete Barrier and a Rigid Concrete Buttress

From 2010 to 2015, MwRSF researchers developed the RESTORE barrier, which is a restorable MASH TL-4 median barrier with a steel and concrete rail supported by elastomer posts and steel skids. The research effort reported herein describes the initial development of a transition from the RESTORE barrier to a rigid TL-4 concrete buttress. The previously-developed RESTORE barrier LS-DYNA model was validated against three full-scale vehicle crash tests. Several design concepts were generated through a series of brainstorming efforts. The primary transition concept consisted of a pin and loop connection between the RESTORE barrier and rigid concrete buttress, which was designed and evaluated with LS-DYNA computer simulation. Vehicle and system behavior were investigated using MASH test designation nos. 4-20, 4-21, and 4-22. Six horizontal gusset plates and drop-down pin allowed for limited deflection and rotation at the transition joint, but provided shear continuity between the two systems. A rounded-edge cover plate mitigated vehicle snag on the transition joint hardware. Eleven impact points were evaluated with each vehicle model to determine critical impact points for use in a future full-scale crash testing program. All occupant risk measures and vehicle stability were within MASH limits. Further design modifications are recommended to limit stresses in the transition joint hardware and to reduce excessive occupant compartment deformation that occurred when the small car impacted the concrete buttress end. Advisor: Ronald K. Falle

Development of a Transition Between an Energy-Absorbing Concrete Barrier and a Rigid Concrete Buttress

From 2010 to 2015, MwRSF researchers developed the RESTORE barrier, which is a restorable MASH TL-4 median barrier with a steel and concrete rail supported by elastomer posts and steel skids. The research effort reported herein describes the initial development of a transition from the RESTORE barrier to a rigid TL-4 concrete buttress. The previously-developed RESTORE barrier LS-DYNA model was validated against three full-scale vehicle crash tests. Several design concepts were generated through a series of brainstorming efforts. The primary transition concept consisted of a pin and loop connection between the RESTORE barrier and rigid concrete buttress, which was designed and evaluated with LS-DYNA computer simulation. Vehicle and system behavior were investigated using MASH test designation nos. 4-20, 4-21, and 4-22. Six horizontal gusset plates and drop-down pin allowed for limited deflection and rotation at the transition joint, but provided shear continuity between the two systems. A rounded-edge cover plate mitigated vehicle snag on the transition joint hardware. Eleven impact points were evaluated with each vehicle model to determine critical impact points for use in a future full-scale crash testing program. All occupant risk measures and vehicle stability were within MASH limits. Further design modifications are recommended to limit stresses in the transition joint hardware and to reduce excessive occupant compartment deformation that occurred when the small car impacted the concrete buttress end. Advisor: Ronald K. Falle

Computational Evaluation of Ventricular Assist Device Implementation in the Single Ventricle Circulation

Patients with a single ventricle congenital heart defect are prone to increased volume loading, which can lead to heart failure and require mechanical circulatory support. A ventricular assist device (VAD) can serve as a bridge treatment option for these patients. However, in VAD support cases, pediatric patients possessing congenital heart defects have lower survival rates than patients without and outcomes worsen further in single ventricle cases. Performance differences between pulsatile and continuous flow VADs have also been clinically observed, but the underlying mechanism remains poorly understood. Six pediatric, stage 1 single ventricle patients (cohort mean BSA = 0.30 m2) were considered. The cardiovascular system was computationally simulated using a lumped-parameter network (LPN) tuned to patient specific data. A first set of simulations emulated current clinical implementation of VADs in single ventricle patients. A second set modified VAD settings with the goal to further improve cardiac output (CO). For all patients, optimal CO was at least 1 L min-1 greater with the continuous flow VAD compared that of pulsatile flow (p=0.0009). The 25 and 50 mL pulsatile flow VADs exhibited incomplete filling at higher heart rates that reduced CO as much as 0.26 and 1.4 L min-1 (9.7% and 37.3%) below design expectations respectively. Optimization of pulsatile flow VAD settings to improve filling did not achieve statistically significant (p\u3c0.05) improvement. Results corroborate anecdotal clinical experience associating continuous flow VADs with superior CO and ventricular unloading in single ventricle patients. Future work should aim to improve models for ventricular suction resistance and the passive pressure-volume relationship at negative ventricular pressures. As part of future work, the single ventricle LPN was modified to simulate resting and exercise physiologies of example adult patients with normal bi-ventricular circulations. Correlations with exercise level for key physiological parameters were developed using prior literature data. Considerations for patient fitness level and age were also incorporated as appropriate. This model produced resting physiology within tolerance of prior literature data and exercise physiologies for two example patients within 10% of prior data for CO and mean arterial pressure. This modified LPN serves as a platform for future work in computational studies of bi-ventricular patients

A Real-Time Programmable Pulsatile Flow Pump for In Vitro Cardiovascular Experimentation

Benchtop in vitro experiments are valuable tools for investigating the cardiovascular system and testing medical devices. Accurate reproduction of the physiologic flow waveforms at various anatomic locations is an important component of these experimental methods. This study discusses the design, construction, and testing of a low-cost and fully programmable pulsatile flow pump capable of continuously producing unlimited cycles of physiologic waveforms. It consists of a gear pump actuated by an AC servomotor and a feedback algorithm to achieve highly accurate reproduction of flow waveforms for flow rates up to 300 ml/s across a range of loading conditions. The iterative feedback algorithm uses the flow error values in one iteration to modify the motor control waveform for the next iteration to better match the desired flow. Within four to seven iterations of feedback, the pump replicated desired physiologic flow waveforms to within 2% normalized RMS error (for flow rates above 20 mL/s) under varying downstream impedances. This pump device is significantly more affordable (∼10% of the cost) than current commercial options. More importantly, the pump can be controlled via common scientific software and thus easily implemented into large automation frameworks

Interspecific Breeding for Warm-Winter Tolerance in Tulipa gesneriana L.

Focus on breeding of Tulipa gesneriana has largely concentrated on appearance. Through interspecific breeding with more warm-tolerant species, tolerance of warm winters could be introduced into the species, decreasing dormancy requirements and expanding the range of tulips southward. Additionally, long-lasting foliage can be favored in breeding to allow plants to store more energy for daughter bulbs. Continued virus and fungal resistance breeding will decrease infection. Primary benefits are for gardeners and landscapers who, under the current planting schedule, are planting tulip bulbs annually, wasting money. Producers benefit from this by reducing cooling times, saving energy, greenhouse space, and tulip bulbs lost to diseases in coolers

The Externalities Associated with Various Heating Sources at Bates College

The aim of this report is to determine the costs associated with the externalities of #2 fuel oil, natural gas, biomass, and renewable fuel oil. Externalities occur when a market transaction imposes costs on parties external to that transaction. These four energy sources are options Bates College is considering for heating its campus, either through the central steam plant or separate boiler systems. Evaluating the costs of these externalities will provide a picture of the true cost of energy, allowing the school to make a decision with complete information regarding the implications of using these energy sources. The methodology for estimating the cost of externalities differs for the two groups of energy sources. The values for #2 fuel oil and natural gas largely follow the methodology of the ExternE report of the European Commission, in which empirical modeling and case studies provide for the estimates of various externalities of fuel sources used across Europe. The findings of the ExternE report are supplemented with outside literature in order to confirm that the ExternE methodology is valid, and to provide additional externality cost information lacking in the report. This study finds that there are a range of externality costs associated with the use of #2 fuel oil and natural gas, from the costs of health effects to atmospheric pollution. Biomass and renewable fuel oil follow similar methodologies in terms of evaluating the costs of externalities. Various sources of literature are used to determine the possible mechanisms in which externalities may exist through the use of these energy types, and to determine their impact in terms of a monetary value. As these two energy sources are very recent additions to the market, reports beyond those available in the academic literature are also relied upon to provide information. One of the major contributors to externalities associated with renewable fuel oil is the Pacific Northwest National research Lab (PNNL). This report finds that the externality costs associated with biomass and renewable fuel oil are minimal compared to the other energy sources, as the primary externality costs are associated with the transportation of these materials. The results of this study are reported as lower bounds for fossil fuel externalities and upper bounds for renewable fuel externalities. By reporting the renewable fuel externalities as upper bounds, we can show the worst-case scenario associated with renewables. This will provide a contrasting figure to our minimum conservative values for fossil fuels that show the best-case scenario. These values are estimates due to our understanding that certain impacts cannot be valued monetarily given the complexity of the relationships among these energy markets, the economy, and the environment

Hydrogen-atom Attack on Phenol and Toluene is \u3cem\u3eortho\u3c/em\u3e-directed

The reaction of H + phenol and H/D + toluene has been studied in a supersonic expansion after electric discharge. The (1 + 1′) resonance-enhanced multiphoton ionization (REMPI) spectra of the reaction products, at m/z = parent + 1, or parent + 2 amu, were measured by scanning the first (resonance) laser. The resulting spectra are highly structured. Ionization energies were measured by scanning the second (ionization) laser, while the first laser was tuned to a specific transition. Theoretical calculations, benchmarked to the well-studied H + benzene → cyclohexadienyl radical reaction, were performed. The spectrum arising from the reaction of H + phenol is attributed solely to the ortho-hydroxy-cyclohexadienyl radical, which was found in two conformers (syn and anti). Similarly, the reaction of H/D + toluene formed solely the ortho isomer. The preference for the ortho isomer at 100–200 K in the molecular beam is attributed to kinetic, not thermodynamic effects, caused by an entrance channel barrier that is ∼5 kJ mol−1 lower for ortho than for other isomers. Based on these results, we predict that the reaction of H + phenol and H + toluene should still favour the ortho isomer under elevated temperature conditions in the early stages of combustion (200–400 °C)

Development of a Transition Between an Energy-Absorbing Concrete Barrier and a Rigid Concrete Butress

From 2010 to 2015, MwRSF researchers developed the RESTORE barrier, which is a restorable MASH TL-4 median barrier with a steel and concrete rail supported by elastomer posts and steel skids. The research effort reported herein describes the initial development of a transition from the RESTORE barrier to a rigid TL-4 concrete buttress. The previously-developed RESTORE barrier LS-DYNA model was validated against three full-scale vehicle crash tests. Several design concepts were generated through a series of brainstorming efforts. The primary transition concept consisted of a pin and loop connection between the RESTORE barrier and rigid concrete buttress, which was designed and evaluated with LS-DYNA computer simulation. Vehicle and system behavior were investigated using MASH test designation nos. 4-20, 4-21, and 4-22. Six horizontal gusset plates and drop-down pin allowed for limited deflection and rotation at the transition joint, but provided shear continuity between the two systems. A rounded-edge cover plate mitigated vehicle snag on the transition joint hardware. Eleven impact points were evaluated with each vehicle model to determine critical impact points for use in a future full-scale crash testing program. All occupant risk measures and vehicle stability were within MASH limits. Further design modifications are recommended to limit stresses in the transition joint hardware and to reduce excessive occupant compartment deformation that occurred when the small car impacted the concrete buttress end