A Lightweight Remote Sensing Payload for Wildfire Detection and Fire Radiative Power Measurements.

Small uncrewed aerial systems (sUASs) have the potential to serve as ideal platforms for high spatial and temporal resolution wildfire measurements to complement aircraft and satellite observations, but typically have very limited payload capacity. Recognizing the need for improved data from wildfire management and smoke forecasting communities and the potential advantages of sUAS platforms, the Nighttime Fire Observations eXperiment (NightFOX) project was funded by the US National Oceanic and Atmospheric Administration (NOAA) to develop a suite of miniaturized, relatively low-cost scientific instruments for wildfire-related measurements that would satisfy the size, weight and power constraints of a sUAS payload. Here we report on a remote sensing system developed under the NightFOX project that consists of three optical instruments with five individual sensors for wildfire mapping and fire radiative power measurement and a GPS-aided inertial navigation system module for aircraft position and attitude determination. The first instrument consists of two scanning telescopes with infrared (IR) channels using narrow wavelength bands near 1.6 and 4 µm to make fire radiative power measurements with a blackbody equivalent temperature range of 320-1500 °C. The second instrument is a broadband shortwave (0.95-1.7 µm) IR imager for high spatial resolution fire mapping. Both instruments are custom built. The third instrument is a commercial off-the-shelf visible/thermal IR dual camera. The entire system weighs about 1500 g and consumes approximately 15 W of power. The system has been successfully operated for fire observations using a Black Swift Technologies S2 small, fixed-wing UAS for flights over a prescribed grassland burn in Colorado and onboard an NOAA Twin Otter crewed aircraft over several western US wildfires during the 2019 Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) field mission.

Membrane nanodomains homeostasis during propofol anesthesia as function of dosage and temperature.

Some anesthetics bind and potentiate γ-aminobutyric-acid-type receptors, but no universal mechanism for general anesthesia is known. Furthermore, often encountered complications such as anesthesia induced amnesia are not understood. General anesthetics are hydrophobic molecules easily dissolving into lipid bilayers. Recently, it was shown that general anesthetics perturb phase separation in vesicles extracted from fixed cells. Unclear is whether under physiological conditions general anesthetics induce perturbation of the lipid bilayer, and whether this contributes to the transient loss of consciousness or anesthesia side effects. Here we show that propofol perturbs lipid nanodomains in the outer and inner leaflet of the plasma membrane in intact cells, affecting membrane nanodomains in a concentration dependent manner: 1 µM to 5 µM propofol destabilize nanodomains; however, propofol concentrations higher than 5 µM stabilize nanodomains with time. Stabilization occurs only at physiological temperature and in intact cells. This process requires ARP2/3 mediated actin nucleation and Myosin II activity. The rate of nanodomain stabilization is potentiated by GABAA receptor activity. Our results show that active nanodomain homeostasis counteracts the initial disruption causing large changes in cortical actin. SIGNIFICANCE STATEMENT: General anesthesia is a routine medical procedure with few complications, yet a small number of patients experience side-effects that persist for weeks and months. Very young children are at risk for effects on brain development. Elderly patients often exhibit subsequent amnesia. Here, we show that the general anesthetic propofol perturbs the ultrastructure of the lipid bilayer of the cell membrane in intact cells. Initially propofol destabilized lipid nanodomains. However, with increasing incubation time and propofol concentration, the effect is reversed and nanodomains are further stabilized. We show that this stabilization is caused by the activation of the actin cortex under the membrane. These perturbations of membrane bilayer and cortical actin may explain how propofol affects neuronal plasticity at synapses.

Nonconcordance between Clinical and Head CT Findings: The Specter of Overdiagnosis.

Background. It is unclear whether history and physical examination findings can predict abnormalities on head computed tomography (CT) believed to indicate increased risk of lumbar-puncture- (LP-) induced brain herniation. The objectives of this study were to (1) identify head CT findings felt to be associated with increased risk of brain herniation and (2) to assess the ability of history and physical examination to predict those findings. Methods. Using a modified Delphi survey technique, an expert panel defined CT abnormalities felt to predict increased risk of LP-induced brain herniation. Presence of such findings on CT was compared with history and physical examination (H&P) variables in 47 patients. Results. No H&P variable predicted "high-risk" CT; combining H&P variables to improve sensitivity led to extremely low specificity and still failed to identify all patients with high-risk CT. Conclusions. "High-risk" CT is not uncommon in patients with clinical characteristics known to predict an absence of actual risk from LP, and thus it may not be clinically relevant. "Overdiagnosis" will be increasingly problematic as technological advances identify increasingly subtle deviations from "normal."

Injuries missed by limited computed tomographic imaging of patients with cervical spine injuries.

STUDY OBJECTIVE: It has been prominently suggested that computed tomographic (CT) imaging is unnecessary in evaluating patients who have one of a number of specific index cervical spine injuries identified on plain radiographs. We seek to evaluate this recommendation by examining how frequently patients with these index cervical spine injuries have additional secondary injuries that are missed on plain radiography. METHODS: We identified all patients in the National Emergency X-Radiography Utilization Study (NEXUS) cervical spine data set who had an index cervical spine injury identified by plain radiography. We reviewed all radiographic studies done on each of these patients, including CT, to determine whether any patient sustained additional cervical spine injuries not visualized on plain radiographs. RESULTS: Of 818 patients with cervical spine injuries in NEXUS, 224 had one of these index cervical spine injuries diagnosed on plain film radiography. Eighty-one of these 224 patients (36.2%; 95% confidence interval [CI] 29.9% to 42.8%) had at least 1 secondary injury that was not identified on plain radiography. A noncontiguous spinal injury was found in 22 of these 81 patients (27.2%; 95% CI 17.9% to 38.2%) with multiple cervical spine injuries. CONCLUSION: More than a third of patients who had one of the index cervical spine injuries sustained a secondary injury that was not diagnosed by plain radiography, and approximately one fourth of the patients with multiple cervical spine injuries have a noncontiguous spinal injury. Guidelines about the necessity for CT scanning in such patients should be reconsidered.

Developing a decision instrument to guide computed tomographic imaging of blunt head injury patients.

BACKGROUND: Computed tomographic (CT) head scanning of blunt trauma patients is expensive, delays care, and necessitates radiation exposure, while detecting intracranial injuries in a minority of patients. Clinical characteristics may be able reliably identify patients who do not have intracranial injuries and consequently, do no require imaging. METHODS: Physicians assessed blunt trauma patients undergoing imaging for the presence or absence of specific criteria. Recursive partitioning was used to identify criteria that predict intracranial injuries with high sensitivity. RESULTS: Intracranial injuries were found in 917 of 13,728 enrolled patients (6.7%). Injuries were rare among patients under age 65 who had no evidence of skull fracture, scalp hematoma, neurologic deficit, abnormal alertness, abnormal behavior, coagulopathy, or persistent vomiting. These characteristics would have identified 901 injury cases (sensitivity 98.3% [CI: 97.2-99.0]), while classifying 1,752 patients (12.8%) as "low risk." CONCLUSIONS: Clinical characteristics can reliably identify patients who are unlikely to have intracranial injuries and who do not require CT imaging.

Active correction of thermal lensing through external radiative thermal actuation.

Absorption of laser beam power in optical elements induces thermal gradients that may cause unwanted phase aberrations. In precision measurement applications, such as laser interferometric gravitational-wave detection, corrective measures that require mechanical contact with or attachments to the optics are precluded by noise considerations. We describe a radiative thermal corrector that can counteract thermal lensing and (or) thermoelastic deformation induced by coating and substrate absorption of collimated Gaussian beams. This radiative system can correct anticipated distortions to a high accuracy, at the cost of an increase in the average temperature of the optic. A quantitative analysis and parameter optimization is supported by results from a simplified proof-of-principle experiment, demonstrating the method's feasibility for our intended application.

Solid-state laser intensity stabilization at the 10(-8) level.

A high-power, low-noise photodetector, in conjunction with a current shunt actuator, is used in an ac-coupled servo to stabilize the intensity of a 10-W cw Nd:YAG laser. A relative intensity noise of 1 x 10(-8) Hz(-1/2) at 10 Hz is achieved.

Supervision of residents by faculty radiologists using home workstations.

Our purpose was to determine if a home-based faculty radiologist equipped with a high-resolution workstation could add new information to residents' readings on overnight computed chest images that was equivalent to the new information generated by faculty reviewers inside the hospital. Teleconferencing software was installed on home workstations for online supervision of residents by faculty on chest images from a cardiothoracic intensive care unit. Critical observations that could affect patient care were recorded by first-year radiology residents before and after teleconferencing with the home-based radiologist. The amount of information added was compared with that which was added on the same 50 images through direct consultations with faculty inside the medical center. The amount of critical information that was added by teleconferencing with a chest radiologist at home was equivalent statistically to the information added through direct supervision of residents by faculty inside the hospital. Teleconferencing resulted in 149 changes in critical image findings as reported initially by the residents, out of 800 possible findings on 50 chest images, as opposed to 142 changes in residents' readings by faculty inside the medical center. Faculty subspecialists can supervise radiology residents effectively from their homes after hours, using high-resolution workstations and special teleconferencing software.

Developing a clinical decision instrument to rule out intracranial injuries in patients with minor head trauma: methodology of the NEXUS II investigation.

The fear of failing to identify brain injury has led to the liberal and potentially excessive use of computed tomographic (CT) scanning of patients with blunt head trauma who have even a remote possibility of intracranial injury. This practice exposes large numbers of patients to the expense and radiation exposure associated with CT imaging while detecting injuries in a small minority. Previous studies suggest that it might be possible to develop a decision instrument to identify patients with blunt head injury who have essentially no risk of significant intracranial injury and for whom CT scanning is therefore unnecessary. Development of such a decision instrument has been identified as a priority among practicing emergency physicians. The National Emergency X-Radiography Utilization Study II (NEXUS II) is a large, multicenter, prospective study designed to derive a decision rule for CT imaging of patients with blunt head injury. This study, conducted in 21 different emergency departments across the United States and Canada, will enroll more than 10 times as many patients with head trauma as any currently published study. NEXUS II should be able to definitively answer questions about the validity and reliability of clinical criteria as a preliminary screen for blunt head trauma.