Evaluation of two collocated federal equivalent method PM2.5 instruments over a wide range of concentrations in Sarajevo, Bosnia and Herzegovina

Two widely used PM_2.5 monitors in the United States (U.S.) designated as federal equivalent methods (FEMs) by the U.S. Environmental Protection Agency were collocated for 15 months in Sarajevo, Bosnia and Herzegovina (BiH) to evaluate their comparability. With differing measurement principles, the FEMs (Met One BAM-1020 and Teledyne API T640) exhibited unique responses to the significant range in PM_2.5 over the study period. During the winter months when concentrations greatly increased (e.g., daily PM_2.5 > 100 μg m^-3), the BAM-1020 had intermittent malfunctioning nozzle contact to the collection tape, resulting in periods of data invalidation. Increased operator observation and doubling the cleaning frequency were required to maintain proper operation. The hourly data from the BAM-1020, which detects PM_2.5 via beta-attenuation of particles loaded to the collection tape, indicated higher noise at concentrations below 40 μg m^-3 relative to the T640, which detects PM_2.5 via an optical method. Above this concentration threshold, the two instruments appear to have comparable hourly fluctuations in the data. Relative to the BAM-1020, the T640 reported higher concentrations when PM_2.5 is above 80 μg m^-3. A linear regression equation was developed and applied to adjust T640 PM_2.5 high concentration values, resulting in 24-hr average T640adj PM_2.5 values closely matching that from the BAM-1020 for the full concentration range. Based on the T640adj values, the annual average for Sarajevo was calculated at the site to be 42 μg m^-3, with significant seasonality resulting in over 7-fold higher concentrations in the months of December-January compared to June-July.

Deliberating Performance Targets: Follow-on workshop discussing PM10, NO2, CO, and SO2 air sensor targets

The use of air sensor technology is increasing worldwide for a variety of applications, however, with significant variability in data quality. The United States Environmental Protection Agency held a workshop in July 2019 to deliberate possible performance targets for air sensors measuring particles with aerodynamic diameters of 10 μm or less (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), and sulfur dioxide (SO2). These performance targets were discussed from the perspective of non-regulatory applications and with the sensors operating primarily in a stationary mode in outdoor environments. Attendees included representatives from multiple levels of government organizations, sensor developers, environmental nonprofits, international organizations, and academia. The workshop addressed the current lack of sensor technology requirements, discussed fit-for-purpose data quality needs, and debated transparency issues. This paper highlights the purpose and key outcomes of the workshop. While more information on performance and applications of sensors is available than in past years, the performance metrics, or parameters used to describe data quality, vary among the studies reports and there is a need for more clear and consistent approaches for evaluating sensor performance. Organizations worldwide are increasingly considering, or are in the process of developing, sensor performance targets and testing protocols. Workshop participants suggested that these new guidelines are highly desirable, would help improve data quality, and would give users more confidence in their data. Given the wide variety of uses for sensors and user backgrounds, as well as varied sensor design features (e.g., communication approaches, data tools, processing/adjustment algorithms and calibration procedures), the need for transparency was a key workshop theme. Suggestions for increasing transparency included documenting and sharing testing and performance data, detailing best practices, and sharing data processing and correction approaches.

Bullous pemphigoid associated with ipilimumab therapy for advanced metastatic melanoma

Immunotherapy is now being routinely used in the management of many cancers. It is therefore vital that all clinicians are aware of the diverse array of cutaneous manifestations that can result from their use, which can vary from mild to life threatening.

Influential factors affecting black carbon trends at four sites of differing distance from a major highway in Las Vegas

Elevated air pollution levels adjacent to major highways are an ongoing topic of public health concern worldwide. Black carbon (BC), a component of particulate matter (PM) emitted by diesel and gasoline vehicles, was measured continuously via a filter-based light absorption technique over ~ 16 months at four different stations positioned on a perpendicular trajectory to a major highway in Las Vegas, NV. During downwind conditions (winds from the west), BC at 20 m from the highway was 32 and 60% higher than concentrations at 100 and 300 m from the roadway, respectively. Overall highest roadside (20-m site) BC concentrations were observed during the time period of 4 a.m.-8 a.m. under low-speed variable winds (3.02 μg/m³) or downwind conditions (2.84 μg/m³). The 20-m site BC concentrations under downwind conditions are 85% higher on weekday periods compared to weekends during the time period of 4 a.m.-8 a.m. Whereas total traffic volume was higher on weekdays versus weekends and differed by approximately 3% on weekdays versus weekends, similarly, the detected heavy-duty fraction was higher on weekdays versus weekends and differed by approximately 21% on weekdays versus weekend. Low wind speeds predominated during early morning hours, leading to higher BC concentrations during early morning hours despite the maximum traffic volume occurring later in the day. No noticeable impact from the airport or nearby arterial roadways was observed, with the 300-m site remaining the lowest of the four-site network when winds were from the east. Multivariate linear regression analysis revealed that heavy-duty traffic volume, light-duty traffic volume, wind speed, weekday versus weekend, surface friction velocity, ambient temperature, and the background BC concentration were significant predictors of roadside BC concentrations. Comparison of BC and PM_2.5 downwind concentration gradients indicates that the BC component contributes substantially to the PM_2.5 increase in roadside environments. These results suggest that BC is an important indicator to assess the contribution of primary traffic emissions to near-road PM_2.5 concentrations, providing opportunities to evaluate the feasibility and effectiveness of mitigation strategies.

Preparation of phytantriol cubosomes by solvent precursor dilution for the delivery of protein vaccines

Different delivery strategies to improve the immunogenicity of peptide/protein-based vaccines are currently under investigation. In this study, the preparation and physicochemical characterisation of cubosomes, a novel lipid-based particulate system currently being explored for vaccine delivery, was investigated. Cubosomes were prepared from a liquid precursor mixture containing phytantriol or glycerylmonooleate (GMO), F127 for particle stabilisation, and a hydrotrope (ethanol or polyethylene glycol (PEG(200)) or propylene glycol (PG)). Several liquid precursors were prepared, and the effect of varying the concentrations of F127 and the hydrotrope on cubosome formation was investigated. Formulations were prepared by fragmentation for comparison. The model protein ovalbumin (Ova) was also entrapped within selected formulations. Submicron-sized particles (180-300 nm) were formed spontaneously upon dilution of the liquid precursors, circumventing the need for the preformed cubic phase used in traditional fragmentation-based methods. The nanostructure of the phytantriol dispersions was determined to be cubic phase using SAXS whilst GMO dispersions had a reverse hexagonal nanostructure coexisting with cubic phase. The greatest entrapment of Ova was within phytantriol cubosomes prepared from liquid precursors. Release of Ova from the various formulations was sustained; however, release was significantly faster and the extent of release was greater from fragmented dispersions compared to liquid precursor formulations. Taken together, these results suggest that phytantriol cubosomes can be prepared using liquid precursors and that it is a suitable alternative to GMO. Furthermore, the high entrapment and the slow release of Ova in vitro highlight the potential of phytantriol cubosomes prepared using liquid precursors as a novel vaccine delivery system.

The national ambient air monitoring strategy: rethinking the role of national networks

A current re-engineering of the United States routine ambient monitoring networks intended to improve the balance in addressing both regulatory and scientific objectives is addressed in this paper. Key attributes of these network modifications include the addition of collocated instruments to produce multiple pollutant characterizations across a range of representative urban and rural locations in a new network referred to as the National Core Monitoring Network (NCore). The NCore parameters include carbon monoxide (CO), sulfur dioxide (SO2), reactive nitrogen (NOy), ozone (O3), and ammonia (NH3) gases and the major fine particulate matter (PM2.5) aerosol components (ions, elemental and organic carbon fractions, and trace metals). The addition of trace gas instruments, deployed at existing chemical speciation sites and designed to capture concentrations well below levels of national air quality standards, is intended to support both long-term epidemiological studies and regional-scale air quality model evaluation. In addition to designing the multiple pollutant NCore network, steps were taken to assess the current networks on the basis of spatial coverage and redundancy criteria, and mechanisms were developed to facilitate incorporation of continuously operating particulate matter instruments.

Defining "dead on arrival": impact on a level I trauma center

OBJECTIVE

To determine the potential impact of defining criteria for "dead on arrival" (DOA) on a Level I trauma center.

METHODS

From 1990 to 1994, trauma patients having cardiopulmonary resuscitation (CPR) performed by certified prehospital personnel were reviewed for time of CPR, outcome, and costs to determine whether any benefit would have been realized had DOA criteria been followed.

RESULTS

A total of 106 patients had prehospital CPR; 20 did not meet DOA criteria and underwent resuscitation, three survived (15%). Eighty-six patients met DOA criteria; 16 were pronounced dead without further resuscitative efforts (in-hospital costs of $200/patient), while 70 (81%) had continued resuscitation with no survivors (in-hospital costs of $4150/patient). The positive predictive value for criteria was 100%. Had criteria been implemented, total cost savings over the 5-year period would have been $290,000.

CONCLUSIONS

National DOA criteria could dramatically reduce the burden on trauma centers with an estimated minimum annual savings of $14 million.

Selective expression of an acetylcholine receptor-lacZ transgene in synaptic nuclei of adult muscle fibers

Acetylcholine receptors (AChRs) are highly concentrated in the postsynaptic membrane at the neuromuscular junction. To investigate mechanisms that lead to the formation or maintenance of this synaptic specialization, we generated transgenic mice in which regulatory elements from the AChR alpha or epsilon-subunit genes are linked to a gene for a reporter protein that is targeted to the nucleus (nlacZ). Both transgenes were selectively expressed and developmentally regulated in muscle; nuclei in both extrafusal (ordinary) and intrafusal (spindle) muscle fibers were labeled. Within individual muscle fibers from epsilon-nlacZ mice, nuclei near synaptic sites were nlacZ-positive, whereas extrasynaptic nuclei were nlacZ-negative. In contrast, nlacZ was expressed in both synaptic and extrasynaptic nuclei when under the control of regulatory elements from the AChR alpha-subunit gene; however, synaptic nuclei were somewhat more intensely stained than extrasynaptic nuclei in a minority of muscle fibers from these mice. Together, our results provide direct evidence for molecular differences between synaptic and extrasynaptic nuclei within a single cytoplasm, and suggest that the motor nerve regulates synapse formation by selectively affecting transcription in synaptic nuclei.

Prevalence of Otitis Media with Effusion in a Group of Preschool Children in the United States

There is a paucity of information regarding the prevalence and natural history of OME. This makes reaching decisions regarding screening and management difficult. Two longitudinal studies are in progress. One involves the application of strict diagnostic criteria to evaluate OME and hearing in a small population of preschool children. The other follows newborn twins for 3 years to establish the influence of genetics and/or environment on the etiology of otitis media, but will also provide information on the incidence and natural history of the disease.

A fat-mobilizing factor in rat serum

The serum of rats promoted triglyceride breakdown in isolated adipose tissue cells incubated in vitro, as shown by increased glycerol release into the medium. The serum of fed rats had a smaller fat-mobilizing action than that of rats fasted for 20 h. There was a very close linear relation of dose-response versus dose, as occurs in other physiological responses provoked by a hormone acting on a limited number of receptors. The maximum lipolytic effect of serum from fasted animals was of the same order as the maximum effect of noradrenaline, and amounted to a breakdown of about 1.5% of the adipose cell triglyceride per hour. The triglyceride breakdown provoked by serum was inhibited by the β-blocking drug propranolol, but was not affected by insulin even in high concentration.

Total nitrogen and L-hydroxyproline content of adipose tissue from various sites in rats of different ages

The total nitrogen and L-hydroxyproline concentrations of two intra-abdominal and two subcutaneous sites of adipose tissue were measured in male and female Wistar rats. At 100 g body weight the nitrogen concentration of intra-abdominal adipose tissue was slightly lower than that of subcutaneous adipose tissue. As age advanced beyond sexual maturity, the nitrogen content of intra-abdominal adipose tissue was steadily reduced, whereas that of subcutaneous tissue did not change. The L-hydroxyproline concentration of intra-abdominal adipose tissue was also lower than in subcutaneous adipose tissue. In male rats it rose in most adipose tissue sites when sexual maturity was reached, then fell with advancing age. In female rats the pattern of change was less consistent, but the l-hydroxyproline content of intra-abdominal adipose tissue was reduced as age increased.

Insulin sensitivity and carbohydrate metabolism of rats with hypothalamic obesity

A fixed dose of glucose, irrespective of body weight, used for i.v. glucose tolerance tests in rats with hypothalamic obesity and in non-obese control rats caused almost identical blood glucose increments in both kinds of rats, and the K values (coefficients of glucose assimilation) were not significantly different. Glucose doses proportional to body weight caused much larger increments of blood glucose in the obese animals but the K value was not significantly different from that for the controls.

On the other hand, the insulin sensitivity of obese rats was found to be less than that of control rats when a fixed dose of the hormone was given. When the insulin dosage was proportional to body weight, the fall of fasting blood glucose produced in the obese animals was not significantly different from that in the control group. In vitro, the diaphragm muscle of the obese animals was insensitive to the action of insulin as compared with controls. There was no evidence of insulin insensitivity of the obese animals' adipose tissue; the very low metabolic activity of the adipose tissue of both the control and obese animals may have been responsible. The interpretation of these findings is discussed in the light of similar work in human obesity.