Digital electric field induced switching of plasmonic nanorods using an electro-optic fluid fiber

We demonstrate the digital electric field induced switching of plasmonic nanorods between 1 and 0 orthogonal aligned states using an electro-optic fluid fiber component. We show by digitally switching the nanorods, that thermal rotational diffusion of the nanorods can be circumvented, demonstrating an approach to achieve submicrosecond switching times. We also show, from an initial unaligned state, that the nanorods can be aligned into the applied electric field direction in 110 nanoseconds. The high-speed digital switching of plasmonic nanorods integrated into an all-fiber optical component may provide novel opportunities for remote sensing and signaling applications

Lower Extremity Stiffness in Collegiate Distance Runners Pre- and Post-Competition

Previous evidence has suggested that there is a relationship between leg stiffness and improved running performance. The purpose of this investigation was to determine how leg stiffness of runners was influenced in the 24 and 48 hour period following a cross country race. Twenty-two collegiate cross-country runners (13 males, 9 females, 19.5 ± 1.4 yr) were recruited and participated in the study. Leg stiffness was assessed 24 hours before and after a race as well as 48 hours post-race. Three jumping protocols were conducted: 1) a static jump, 2) a countermovement jump, and 3) a vertical hopping test. Two embedded force plates (1000 Hz) were utilized to measure ground reaction forces for each test and a metronome was utilized to maintain hopping frequency (2.2 Hz). A significant main effect was found for a static jump, a countermovement jump and leg stiffness. Leg stiffness was significantly reduced 24 hours post-race (pre-race 36.84 kN·m-1, 24h post 33.11 kN·m-1, p \u3c 0.05), but not 48 hours post-race (36.30 kN·m-1). No significant differences were found in post-hoc analysis for the squat jump, countermovement jump height and the eccentric utilization ratio. Following a cross-country race, leg stiffness significantly declined in a group of collegiate runners in the immediate 24 hours post-race, but returned to baseline 48 hours post-race. Sport scientists and running coaches may be able to monitor leg stiffness as a metric to properly prescribe training regiments

Additive Manufacturing of Heat Exchangers

The Advanced Research Project Agency (ARPA) includes the Advanced Research In Dry cooling (ARID) program. The objective of the ARID program is to develop technologies that allow power plants to achieve high thermal-to-electric energy conversion efficiency with zero net water consumption. The most direct method of achieving this goal is to improve the thermal efficiency of dry-cooled condensers by reducing the air-side thermal resistance without significantly increasing either the capital cost or the fan power required to operate these devices. One approach to this is the application of additive manufacturing to dry cooled condensers in order to obtain a low cost, high performance heat rejection system. Conversations with air-cooled heat exchanger manufacturers have resulted in aggressive cost targets that must be met in order to make this technology commercially viable in relevant first markets. A leading manufacturer of air-to-water heat exchangers has indicated that their “gold-standard” heat exchanger for HVAC&R applications achieves economic and thermal performance of approximately $10/kW­th and 7kWth/kg, respectively. This represents the limit of state-of-the-art air-cooled system performance that is the product of a many decades of engineering research; the limits of this technology are unlikely to change using conventional approaches since geometric constraints and costs are largely dictated by the manufacturing technology. The application of additive manufacturing to heat exchangers allows an unparalleled freedom in design. Fused Filament Fabrication (FFF) is a relatively low cost additive manufacturing process that involves depositing thermoplastic material layer by layer. The coupling of FFF with numerical models of air-side thermal fluid behavior has led to a novel, compact, high performance heat exchanger design that has been manufactured and validated experimentally. The heat exchanger features water and air in cross flow with an airfoil fin array on the air-side. Design paths towards cost and performance targets that will allow this technology to be competitive with industry targets have been identified and include: better understanding for manufacturing process constraints, filled material development, and air-side convection improvements. In the FFF process, physical geometrical constraints such as extrusion nozzle diameter and layer height have implications on thermal performance, overall resistance to heat transfer, and manufacturability. Typical thermoplastic thermal conductivities are 100 to 1000 times smaller than that of the aluminum and copper used in industry standard heat exchangers. Efforts to manufacture polymers that are filled with conductive materials such as carbon fiber, aluminum flakes, and graphite aim to decrease this gap by an order of magnitude. To be competitive with traditional air-cooled heat exchangers with material that is much less conductive, air-side convection optimization using Computational Fluid Dynamics (CFD) has been utilized to implement and validate advanced air-side geometries. An FFF manufactured heat exchanger that is cost and performance competitive with traditionally manufactured heat exchangers will open the door to a future in air-cooled systems that currently does not exist. This technology will allow heat exchangers to become lighter and fit in a smaller envelope as well as result in rapid replacement, high customization, fouling resistance and other secondary advantages

In vivo DNA assembly using common laboratory bacteria: A re-emerging tool to simplify molecular cloning

Molecular cloning is a cornerstone of biomedical, biotechnological, and synthetic biology research. As such, improved cloning methodologies can significantly advance the speed and cost of research projects. Whereas current popular cloning approaches use in vitro assembly of DNA fragments, in vivo cloning offers potential for greater simplification. It is generally assumed that bacterial in vivo cloning requires Escherichia coli strains with enhanced recombination ability; however, this is incorrect. A widely present, bacterial RecA-independent recombination pathway is re-emerging as a powerful tool for molecular cloning and DNA assembly. This poorly understood pathway offers optimal cloning properties (i.e. seamless, directional, and sequence-independent) without requiring in vitro DNA assembly or specialized bacteria, therefore vastly simplifying cloning procedures. Although the use of this pathway to perform DNA assembly was first reported over 25 years ago, it failed to gain popularity, possibly due to both technical and circumstantial reasons. Technical limitations have now been overcome, and recent reports have demonstrated its versatility for DNA manipulation. Here, we summarize the historical trajectory of this approach and collate recent reports to provide a roadmap for its optimal use. Given the simplified protocols and minimal requirements, cloning using in vivo DNA assembly in E. coli has the potential to become widely employed across the molecular biology community

Recruiting Undergraduate Students: Creating a Path to the Counseling Profession

Counselor educators must find ways to encourage undergraduate students to choose to pursue a graduate degree in counseling. Related helping professions (e.g., psychology, social work) may have a recruitment advantage. Faculty in disciplines with both undergraduate and graduate programs can encourage high achieving undergraduate students to continue into graduate programs within their discipline. Due to the lack of a discipline specific academic pathway and an undergraduate advising system directing students into counseling graduate programs, counselor educators must find innovative ways to recruit undergraduate students. The authors will discuss the issues involved in recruiting undergraduate students, present a framework for sharing information about the counseling profession, and provide strategies for recruiting undergraduate students into counseling graduate programs

Evaluation and Long-Term Outcomes of Cardiac Toxicity in Paediatric Cancer Patients

Paediatric cancer survival rates have increased dramatically in the last 20 years. With decreased mortality comes increased long-term morbidity. Cardiovascular disease is the leading cause of secondary morbidity and mortality of childhood cancer survivors. The most common chemotherapeutic agents in treatment regimens are implicated in chemotherapy-induced cardiomyopathy. The clinical presentation is rarely uniform and may manifest in symptoms besides chest pain, shortness of breath or decreased exercise tolerance. In addition to symptomatic patients, asymptomatic patients are especially important to screen as the effects of cardiac toxicity are reversible if caught early. There are new techniques more sensitive than traditional 2D echocardiography ejection fraction that may lead to earlier detection of cardiac dysfunction. Treatment methods have changed little in the recent past with the exception of miniaturization of support devices allowing for cardiac recovery or bridge to cardiac transplant