Mid-infrared trace detection with parts-per-quadrillion quantitation accuracy: Expanding frontiers of radiocarbon sensing.

Detection sensitivity is a critical characteristic to consider during selection of spectroscopic techniques. However, high sensitivity alone is insufficient for spectroscopic measurements in spectrally congested regions. Two-color cavity ringdown spectroscopy (2C-CRDS), based on intra-cavity pump-probe detection, simultaneously achieves high detection sensitivity and selectivity.

Room-Temperature Optical Detection of CO below the Natural Abundance with Two-Color Cavity Ring-Down Spectroscopy.

Radiocarbon's natural production, radiative decay, and isotopic rarity make it a unique tool to probe carbonaceous systems in the life and earth sciences. However, the difficulty of current radiocarbon (C) detection methods limits scientific adoption. Here, two-color cavity ring-down spectroscopy detects CO in room-temperature samples with an accuracy of one-tenth the natural abundance in 3 min.

Two-color, intracavity pump-probe, cavity ringdown spectroscopy.

We report a proof-of-principle demonstration of intracavity pump-probe, cavity ringdown (CRD) detection in a three-mirror, traveling-wave cavity. With cavity-enhanced pump power and probe absorption path length, the technique is a generally applicable, high-sensitivity, high-selectivity detection method. In our experiments, the pump radiation is switched off during every other probe ringdown, which allows uncorrelated measurements of analyte and background cavity decay rates.

Radiocarbon Tracers in Toxicology and Medicine: Recent Advances in Technology and Science.

This review summarizes recent developments in radiocarbon tracer technology and applications. Technologies covered include accelerator mass spectrometry (AMS), including conversion of samples to graphite, and rapid combustion to carbon dioxide to enable direct liquid sample analysis, coupling to HPLC for real-time AMS analysis, and combined molecular mass spectrometry and AMS for analyte identification and quantitation. Laser-based alternatives, such as cavity ring down spectrometry, are emerging to enable lower cost, higher throughput measurements of biological samples.

Phase 0, including microdosing approaches: Applying the Three Rs and increasing the efficiency of human drug development.

Phase 0 approaches, including microdosing, involve the use of sub-therapeutic exposures to the tested drugs, thus enabling safer, more-relevant, quicker and cheaper first-in-human (FIH) testing. These approaches also have considerable potential to limit the use of animals in human drug development. Recent years have witnessed progress in applications, methodology, operations, and drug development culture.

Effects of Washington State's alcohol ignition interlock laws on DUI recidivism: An update.

Objective: The objective of this study was to examine the effects of changes to Washington State's alcohol ignition interlock laws: moving issuance of interlock orders from the courts to the driver licensing department (July 2003); extending the interlock order requirement to all persons convicted of driving under the influence (DUI; June 2004); allowing an interlock in lieu of an administrative driver's license suspension (January 2009); and requiring proof of interlock installation to reinstate the driver's license (January 2011).

Method: Trends in conviction types, interlock installation rates, and 2-year cumulative recidivism rates were examined for first-time and repeat offenders with convictions stemming from DUI arrests during 1999-2012. Autoregressive integrated moving average (ARIMA) models examined the association between law changes and installation rates, law changes and recidivism rates, and installation rates and recidivism rates.

Fatally injured pedestrians and bicyclists in the United States with high blood alcohol concentrations.

Introduction: Little research has focused on the problem of alcohol impairment among pedestrians and bicyclists in the United States. The aim of the current study was to investigate the prevalence, trends, and characteristics of alcohol-impaired fatally injured pedestrians and bicyclists.

Method: Data from the Fatality Analysis Reporting System (FARS) were analyzed for fatally injured passenger vehicle drivers, pedestrians, and bicyclists 16 and older during 1982-2014.

Crash risk factors for interstate large trucks in North Carolina.

Introduction: Provide an updated examination of risk factors for large truck involvements in crashes resulting in injury or death.

Methods: A matched case-control study was conducted in North Carolina of large trucks operated by interstate carriers. Cases were defined as trucks involved in crashes resulting in fatal or non-fatal injury, and one control truck was matched on the basis of location, weekday, time of day, and truck type.

Effects of vehicle power on passenger vehicle speeds.

Objectives: During the past 2 decades, there have been large increases in mean horsepower and the mean horsepower-to-vehicle weight ratio for all types of new passenger vehicles in the United States. This study examined the relationship between travel speeds and vehicle power, defined as horsepower per 100 pounds of vehicle weight.

Methods: Speed cameras measured travel speeds and photographed license plates and drivers of passenger vehicles traveling on roadways in Northern Virginia during daytime off-peak hours in spring 2013.

Impaired driving enforcement practices among state and local law enforcement agencies in the United States.

Introduction: Alcohol-impaired driving (DUI) persists as a substantial problem, yet detailed data on DUI enforcement practices are rarely collected. The present study surveyed state and local law enforcement agencies about their DUI enforcement activities.

Method: Telephone interviews were conducted with law enforcement liaisons in state highway safety offices.

Quantifying Carbon-14 for Biology Using Cavity Ring-Down Spectroscopy.

A cavity ring-down spectroscopy (CRDS) instrument was developed using mature, robust hardware for the measurement of carbon-14 in biological studies. The system was characterized using carbon-14 elevated glucose samples and returned a linear response up to 387 times contemporary carbon-14 concentrations. Carbon-14 free and contemporary carbon-14 samples with varying carbon-13 concentrations were used to assess the method detection limit of approximately one-third contemporary carbon-14 levels.

Measurements of Carbon-14 With Cavity Ring-Down Spectroscopy.

Accelerator Mass Spectrometry (AMS) is the most sensitive method for quantitation of C in biological samples. This technology has been used in a variety of low dose, human health related studies over the last 20 years when very high sensitivity was needed. AMS helped pioneer these scientific methods, but its expensive facilities and requirements for highly trained technical staff have limited their proliferation.

Observed activation status of lane departure warning and forward collision warning of Honda vehicles at dealership service centers.

Objective: There are little objective data on whether drivers with lane departure warning and forward collision warning systems actually use them, but self-report data indicate that lane departure warning may be used less and viewed less favorably than forward collision warning. The current study assessed whether the systems were turned on when drivers brought their vehicles to dealership service stations and whether the observational protocol is a feasible method for collecting similar data on various manufacturers' systems.

Methods: Observations of 2013-2015 Honda Accords, 2014-2015 Odysseys, and 2015 CR-Vs occurred at 2 U.

Toyota drivers' experiences with Dynamic Radar Cruise Control, Pre-Collision System, and Lane-Keeping Assist.

Introduction: Advanced crash avoidance and driver assistance technologies potentially can prevent or mitigate many crashes. Previous surveys with drivers have found favorable opinions for many advanced technologies; however, these surveys are not necessarily representative of all drivers or all systems. As the technologies spread throughout the vehicle fleet, it is important to continue studying driver acceptance and use of them.

History and current status of state graduated driver licensing (GDL) laws in the United States.

Introduction: The objective of this study is to describe changes in teenage driver licensing policies in the United States during the past two decades with the introduction of graduated driver licensing (GDL) programs, assess GDL laws currently in place, and discuss the possibilities and likely consequences of further changes.

Methods: The history of laws introducing and amending GDL programs was tracked, based on records maintained by the Insurance Institute for Highway Safety (IIHS). Counts of states included the District of Columbia.

Vehicle choices for teenage drivers: A national survey of U.S. parents.

Introduction: Previous research has shown that many newly licensed teenagers in the United States are driving vehicles with inferior crash protection. The objective of this study was to update and extend previous research on U.S.

Differences in glance behavior between drivers using a rearview camera, parking sensor system, both technologies, or no technology during low-speed parking maneuvers.

This study characterized the use of various fields of view during low-speed parking maneuvers by drivers with a rearview camera, a sensor system, a camera and sensor system combined, or neither technology. Participants performed four different low-speed parking maneuvers five times. Glances to different fields of view the second time through the four maneuvers were coded along with the glance locations at the onset of the audible warning from the sensor system and immediately after the warning for participants in the sensor and camera-plus-sensor conditions.

Multi-modal assessment of on-road demand of voice and manual phone calling and voice navigation entry across two embedded vehicle systems.

One purpose of integrating voice interfaces into embedded vehicle systems is to reduce drivers' visual and manual distractions with 'infotainment' technologies. However, there is scant research on actual benefits in production vehicles or how different interface designs affect attentional demands. Driving performance, visual engagement, and indices of workload (heart rate, skin conductance, subjective ratings) were assessed in 80 drivers randomly assigned to drive a 2013 Chevrolet Equinox or Volvo XC60.

Tracking progress in teenage driver crash risk in the United States since the advent of graduated driver licensing programs.

Introduction: This study examined U.S. teenagers' crash rates since 1996, when the first graduated driver licensing (GDL) program in the United State was implemented.

Critical older driver errors in a national sample of serious U.S. crashes.

Objective: Older drivers are at increased risk of crash involvement per mile traveled. The purpose of this study was to examine older driver errors in serious crashes to determine which errors are most prevalent.

Methods: The National Highway Traffic Safety Administration's National Motor Vehicle Crash Causation Survey collected in-depth, on-scene data for a nationally representative sample of 5470 U.

Rear seat safety: Variation in protection by occupant, crash and vehicle characteristics.

Objectives: Current information on the safety of rear row occupants of all ages is needed to inform further advances in rear seat restraint system design and testing. The objectives of this study were to describe characteristics of occupants in the front and rear rows of model year 2000 and newer vehicles involved in crashes and determine the risk of serious injury for restrained crash-involved rear row occupants and the relative risk of fatal injury for restrained rear row vs. front passenger seat occupants by age group, impact direction, and vehicle model year.

Type, size and age of vehicles driven by teenage drivers killed in crashes during 2008-2012.

Given teenagers' elevated crash rates, it is especially important that their vehicles have key safety features and good crash protection. A profile of vehicles driven by teenagers killed in crashes was developed. Data on vehicles of drivers ages 15-17 and ages 35-50 who died in crashes during 2008-2012 were obtained from the Fatality Analysis Reporting System.

Model-Based, Closed-Loop Control of PZT Creep for Cavity Ring-Down Spectroscopy.

Cavity ring-down spectrometers typically employ a PZT stack to modulate the cavity transmission spectrum. While PZTs ease instrument complexity and aid measurement sensitivity, PZT hysteresis hinders the implementation of cavity-length-stabilized, data-acquisition routines. Once the cavity length is stabilized, the cavity's free spectral range imparts extreme linearity and precision to the measured spectrum's wavelength axis.