The system L transporter is generally considered to be one of the major Na+‐independent carriers for large neutral α‐amino acids in mammalian cells. However, we found that cultured astrocytes from rat brain cortex accumulate gabapentin, a γ‐amino acid, predominantly by this α‐amino acid transport system. Uptake of gabapentin by system L transporter was also examined in synaptosomes and Chinese hamster ovary (CHO) cells. The inhibition pattern displayed by various amino acids on gabapentin uptake in astrocytes and synaptosomes corresponds closely to that observed for the system L transport activity in CHO cells. Gabapentin and leucine have Km values that equal their Ki values for inhibition of each other, suggesting that leucine and gabapentin compete for the same system L transporter. By contrast, gabapentin exhibited no effect on uptake of GABA, glutamate, and arginine, indicating that these latter three types of brain transporters do not serve for uptake of gabapentin. A comparison of computer modeling analysis of gabapentin and l‐leucine structures shows that although the former is a γ‐amino acid, it can assume a conformation that can resemble the L‐form of a large neutral α‐amino acid such as l‐leucine. The steady‐state kinetic study in astrocytes and CHO cells indicates that the intracellular concentrations of gabapentin are about two to four times higher than that of leucine. The uptake levels of these two substrates are inversely related to their relative exodus rates. The concentrating ability by system L observed in astrocytes is consistent with the substantially high accumulation gradient of gabapentin in the brain tissue as determined by microdialysis.

The problem addressed in this phenomenological study was the lack of documentation that supported the lived experiences of crisis intervention team (CIT)-trained police officers related to their field encounters with persons with mental illnesses. The purpose of the study was to explore the lived experiences of officers among CIT-trained police officers to address the problem. The protection motivation theory was aligned closest with the teachings of CIT training as described by the study participants’ lived experiences. Participants provided the study’s collected data, which was composed of completed questionnaires and transcribed interviews. The empirical theoretical framework method of analysis used was a combination of inductive coding and theme analysis that established the results of this study. Key findings of the study identified a significant amount of frustration expressed in the lived experiences of the CIT-trained police officers. Frustration was experienced by officers who applied the protection motivation theory to ensure the well-being of persons experiencing a mental crisis. There was considerable pushback from the public mental health facilities, which added to the frustration experienced by CIT-trained police officers who attempted to navigate treatment with the limited resources available to help persons in mental crisis. The positive social change produced from this study included recommendations to police leadership and mental health advocates to encourage certain CIT-training-related practices that directly impact CIT field encounters with persons in mental crises. Specialized training may promote improved departmental outcomes such as sustainability of gains for those in crises and enable police officer accountability and reliability.

The Thermal Stress Index (TSI) was developed to provide a means for rapidly estimating the physiological severity of exposure to extreme temperatures for shipboard firefighters and to provide a rational means for finding their most effective work rest cycles. It was meant to be an adjunct to discrete event simulation models of human behavior in complex environments. In this way, a modeling tool with the TSI equation could be used to recommend the number of personnel needed onboard for fighting shipboard fires, the least recovery time needed before they could be returned to duties and to estimate the extent of heat casualties while an onboard fire is fought. As a stand-alone algorithm, the TSI could assist management of fire crews using a simple spreadsheet program to estimate safe exposure and recovery times for forest fires, such as those that annually burn US forests and major building fires.As a consequence of being warm blooded, the human body must maintain a fairly constant internal temperature within a narrow range, even though it is exposed to a wide variety of environmental temperature extremes. To keep internal body temperatures within safe limits, excess heat must be released or conserved, primarily through varying the rate and amount of blood circulating through the skin. These involuntary responses usually occur when the temperature of the blood departs from 97-99 F and are kept in balance and controlled by the central nervous system. During extreme heat exposure, with so much blood going to the external surface of the body for cooling, relatively less goes to the active muscles, the brain and other internal organs. As a result, physical endurance declines and mental fatigue occurs, leading to a reduction in stamina, alertness and mental capacity.In addition to intense heat and thick smoke, shipboard firefighters can be exposed to a huge variety of toxic substances while firefighting. In the course of their duties, they also experience strenuous physical activities compounded by the weight and restricted movement of their protective gear. Heat stroke occurs when the body's thermoregulation ability fails or is surpassed and body temperature rises to critical levels, usually over 103 F. This condition is caused by a combination of highly variable internal factors, and its occurrence is difficult to predict. Heat stroke is a medical emergency. The elevated metabolic temperatures caused by a combination of workload and environmental heat load, both of which contribute to heat stroke, are also highly variable and difficult to predict. Nearly half of all heat stroke victims die or have permanent brain damage.The Thermal Stress Index (TSI) was developed to estimate safe exposure durations for firefighters onboard ship. It is intended to be used in discrete event simulations of human behavior to add a degree of realism to estimates of human performance. Models of human ability frequently fail to include performance degradation as a result of human physical limitations such as from sleep loss or heat stress, r...

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