Enhanced propagation of motile bacteria on surfaces due to forward scattering

How motile bacteria move near a surface is a problem of fundamental biophysical interest and is key to the emergence of several phenomena of biological, ecological and medical relevance, including biofilm formation. Solid boundaries can strongly influence a cell's propulsion mechanism, thus leading many flagellated bacteria to describe long circular trajectories stably entrapped by the surface. Experimental studies on near-surface bacterial motility have, however, neglected the fact that real environments have typical microstructures varying on the scale of the cells' motion. Here, we show that micro-obstacles influence the propagation of peritrichously flagellated bacteria on a flat surface in a non-monotonic way. Instead of hindering it, an optimal, relatively low obstacle density can significantly enhance cells' propagation on surfaces due to individual forward-scattering events. This finding provides insight on the emerging dynamics of chiral active matter in complex environments and inspires possible routes to control microbial ecology in natural habitats

Cognitive ability experiment with photosensitive organic molecular thin films

We present an optical experiment which permits to evaluate the information exchange necessary to self-induce cooperatively a well-organized pattern in a randomly activated molecular assembly. A low-power coherent beam carrying polarization and wavelength information is used to organize a surface relief grating on a photochromic polymer thin film which is photo-activated by a powerful incoherent beam. We demonstrate experimentally that less than 1% of the molecules possessing information cooperatively transmit it to the entire photo-activated polymer film.Comment: 16 pages, 4 figure

Burn Shock and Resuscitation: Many Priorities, One Goal

Burn injuries come in a wide variety of presentations, depending on the size and depth of the thermal insult, concurrent traumatic or inhalation injury, as well as the associated physiological response of the burn victim. To minimize patient morbidity and reduce mortality, prompt recognition and tailored treatment strategies are critically important. As the percentage of total body surface area (TBSA) burned increases so do the body’s physiologic response and the associated complexity of management. Understanding the pathophysiology of burn injury allows the practitioner to optimize and individualize burn patient management—a component of care critical to limiting wound progression and improving outcomes. Burn patient care starts with an accurate and thorough burn patient evaluation conducted in person by an experienced provider. For burns >10–15% TBSA, prompt initiation of fluid resuscitation greatly impacts clinical outcomes. Several formulae have been published to guide crystalloid and/or colloid fluid resuscitation in the setting of burn shock. Other important considerations include ambient temperature control, early enteral nutritional support, vitamin and mineral supplementation, assessment for inhalation injury, glycemic control, early recognition of potential complications of large volume resuscitation, potential need for cardiovascular support, and early wound excision and coverage. Burn patients often require multidisciplinary teams to manage the physical, social, and psychological effects associated with their injury. Dedicated burn centers are the ideal places for meeting the complex needs of each burn patient

Wrong-Site Procedures: Preventable Never Events that Continue to Happen

A comprehensive discussion of “never events” or preventable and grievously shocking medical errors that may result in serious morbidity and mortality is incomplete without a thorough analysis of wrong‐site procedures (WSP). These occurrences are often due to multiple, simultaneous failures in team processes and communication. Despite being relatively rare, wrong‐site surgery can be devastating to all parties involved, from patients and families to healthcare workers and hospitals. This chapter provides a general overview of the topic in the context of clinical vignettes discussing specific examples of WSP. The goal of this work is to educate the reader about risk factors and preventive strategies pertinent to WSP, with the hope of propagating the knowledge required to eliminate these “never events.” To that end, the chapter discusses pitfalls in current surgical practice that may contribute to critical safety breakdowns and emphasizes the need for multiple overlapping measures designed to improve patient safety. Furthermore, updated definitions regarding WSP are included in order to better characterize the different types of WSP. Most importantly, this chapter presents evidence‐based support for the current strategies to prevent wrong‐site events. A summary of selected recent wrong‐site occurrences is also provided as a reference for researchers in this important area of patient safety

Modeling and Experimental Validation of a Transient Direct Expansion Heat Pump

Geothermal heat pump technology is currently one of the most interesting technologies used to heat buildings. There are two designs used in the industry: geothermal heat pump using a secondary ground loop and Direct Expansion (DX) ground source heat pump. The latter is less used, possibly because less research has been carried out for the design of this kind of heat pump. In this paper, a transient model using the Comsol Multiphysic of a DX ground heat pump is presented in heating mode with R22, and a comparison with experimental results is presented with a 24-hour test. It is shown that the model was adequately validated by our experiment with only a maximum difference of 15%. Following this validation, a parametric analysis was realised on the geometry of the borehole. This study concluded that to have the best heat extraction of the ground, the pipes shank spacing need to be important without increasing the borehole diameter.Article History: Received January 16th 2017; Received in revised form May 28th 2017; Accepted June 6th 2017; Available onlineHow to Cite This Article: Rousseau, C., Fannou, J.L.C., Lamarche, L. and Kajl, S. (2017) Modeling and Experimental Validation of a Transient Direct Expansion Heat Pump. International Journal of Renewable Energy Development, 6(2), 145-155.https://doi.org/10.14710/ijred.6.2.145-15

Thermalization vs. Isotropization & Azimuthal Fluctuations

Hydrodynamic description requires a local thermodynamic equilibrium of the system under study but an approximate hydrodynamic behaviour is already manifested when a momentum distribution of liquid components is not of equilibrium form but merely isotropic. While the process of equilibration is relatively slow, the parton system becomes isotropic rather fast due to the plasma instabilities. Azimuthal fluctuations observed in relativistic heavy-ion collisions are argued to distinguish between a fully equilibrated and only isotropic parton system produced in the collision early stage.Comment: 12 pages, presented at `Correlations and Fluctuations in Relativistic Nuclear Collisions', MIT, April 05, minor correction

Resuscitation Endpoints in Traumatic Shock: A Focused Review with Emphasis on Point-of-Care Approaches

Trauma resuscitation is a blend of art and science, with the traumatologist at the helm of a large, multidisciplinary team, making split-second decisions and overseeing various parallel processes. Despite tremendous progress over the past few decades, the “art” component continues to play a large part in the overall trauma resuscitation process, with the “science” part slowly but steadily increasing its footprint as a determinant of processes and decisions. Thus, it becomes critical for all clinicians to be able to recognize the evidence-based factors which can be most valuable in guiding trauma resuscitations. This chapter serves as an overview of the current clinical findings, resuscitative endpoints, imaging techniques, and physiologic indices that are most helpful in order to promptly recognize and treat traumatic shock as well as projecting forward to look at novel techniques and biomarkers. Though a single universal marker that accurately and consistently identifies traumatic shock has yet to be discovered, certain factors discussed, such as lactate and base deficit, have been proven to be much more reliable than others

Adverse Events during Intrahospital Transfers: Focus on Patient Safety

Intrahospital transport of patients constitutes an integral part of care delivery in the complex environment of modern hospitals. In general, the more complicated and acute the patient’s condition is, the more likely he or she will require both scheduled and unscheduled trips. The purpose of this chapter is to highlight the potential adverse events associated with intrahospital transfers (IHTs), to discuss the interdepartmental handoff process when patients travel within the walls of a single institution, and finally to provide strategies to prevent adverse events from occurring during the IHT process. A comprehensive literature review, covering some of the most recent developments in this area, has been included in this manuscript. Aspects unique to this presentation include sections dedicated to risk assessment, commonly seen patterns of transfers and complications, as well as the inclusion of family communication as a core component of the process. The overall goal of providers and patient safety champions should be the achievement of “zero incidence” rate of IHT-related events. We hope that this chapter provides a small, but significant, step in the right direction