Long-term accumulation, depth distribution, and speciation of silver nanoparticles in biosolids-amended soils.

Biosolids can be a source of metals and metal nanoparticles. The objective of this study was to quantify and characterize the accumulation and transport of silver (Ag) in a natural soil that has received agronomically recommended rates of biosolids as fertilizer from 1994 to 2017. Total Ag concentrations were measured in biosolids and soil samples collected from 0 to 10 cm between 1996 and 2017. The depth distribution of Ag in soil to 60-cm depth was measured in 2017. Electron microscopy, in combination with X-ray spectroscopy, and X-ray absorption spectroscopy were used to characterize the Ag. The Ag concentrations in the biosolids-amended soil increased steadily from 1996 until 2007, after which the concentrations leveled off at about 1.25 mg Ag kg-1 soil. This corresponded with a decrease of Ag concentrations in biosolids over time. The majority of the Ag (82%) was confined to the top 10 cm of the soil, small amounts (14%) were detected at 10-to-20-cm depth, and trace amounts (4%) were detected at 30-to-40-cm depth. The Ag in the biosolids was identified as S-containing nanoparticles (Ag2 S) with a diameter of 10-12 nm; however, in soil, the Ag concentrations were too low to allow identification of Ag speciation. This study shows that in a real-world field scenario, biosolids applied at agronomic rates represent a long-term, economically viable source of crop nutrients without increasing the concentration of total Ag in soil above a maximum of 1.5 mg Ag kg-1 . This concentration is below estimated ecotoxicity limits for Ag2 S in soil.

Application of Different Commercial Tourniquets by Laypersons: Would Public-access Tourniquets Work Without Training?

BACKGROUND: The White House "Stop the Bleed" campaign has renewed interest in public-access bleeding kits and the use of tourniquets by the lay public. The objective of this study was to determine which type of tourniquet could be applied most effectively by the lay public using only manufacturer instructions included with each tourniquet. METHODS: This prospective study randomized participants to one of four different tourniquets (SOFTT-W, CAT, RMT, SWAT-T). Participants were all over 18 years of age. Individuals with prior military, EMS, or patient-care medical experience were excluded. Using only the manufacturer's packaging instructions, participants were asked to apply a tourniquet on a simulated bleeding arm. A trained observer noted if tourniquet application by the participant was effective, partially effective, or ineffective based on reduction or cessation of simulated blood flow. Participant's application of the tourniquet was also timed (in seconds) by the observer. The primary outcome of our study was the effectiveness of application for each of the four tourniquets. Secondary outcome was time to effective application. RESULTS: A total of 176 participants were enrolled. For untrained laypersons the RMT had the highest effective application rate of 64.4% and was also the most rapidly applied at 100.9 ± 8.8 seconds (95% confidence interval [CI] = 83.1 to 118.6). The SWAT-T had the highest ineffective application rate (55.5%) than any other tourniquet type (p = 0.002). There was no effect of age or education on time to application for any tourniquet type. Effective applications were performed significantly faster than partially effective or ineffective applications (93.4 ± 5.8 [95% CI = 81.7 to 104.9] vs. 136.7 ± 8.7 [95% CI = 118.8 to 154.7] vs. 151.9 ± 8.3 [95% CI = 135.2 to 168.6]; p ≤ 0.001). There was no difference in time between partial and ineffective applications (p = 0.261). CONCLUSIONS: Our study suggests that laypersons could benefit from prior training to effectively apply tourniquets in emergency situations. Of the tourniquets studied, the RMT was the most effectively and most rapidly applied.

Characteristics and Diversity of ACGME Accredited Emergency Medical Services Fellowship Programs.

Introduction: There is a minimal amount of published data regarding to Emergency Medical Services (EMS) fellowship programs. The purpose of this study was to obtain program characteristics and diversity data regarding EMS fellowship programs. Methods: A survey was sent to program directors at all EMS fellowship programs accredited by the Accreditation Council of Graduate Medical Education (ACGME). Data collected included: year program started, year program accredited, unfilled fellow positions, number of EMS faculty, gender, and race/ethnicity. Gender and race/ethnicity data from EMS fellowships were compared to emergency medicine (EM) residencies using data from the American Association of Medical Colleges. Data were analyzed using IBM SPSS with descriptive statistics, and Chi-square tests. Results: The response rate for the survey was 88% (45/51) of all EMS fellowship programs that were accredited at the time of this survey. Most programs (71%) offer a one-year EMS fellowship, with the remaining offering an optional second year. The median number of physician response vehicles per program was 1.0 (IQR 0.0-2.0), with 24% (11/45) not having a dedicated physician response vehicle. This survey identified that 118 EMS fellows have graduated since inception of the accreditation process, while 34 positions went unfilled. The median number of EMS fellow positions per program was 2.0 (IQR 1.0-2.0), with a range of 1 to 4. It was noted that 31% of programs had no female EMS faculty, and 48% of programs had no under-represented minority EMS faculty. There was a significantly larger proportion of female faculty in EM residency programs (30.5%; 949/3,107) compared to EMS fellowships (19%; 53/274), OR = 1.8, 95% CI:1.3-2.5, p < 0.0001. There was a significantly larger proportion of female fellows in EMS (56%; 66/118) vs. female residents in EM (38%; 2,193/5,777), OR" = 2.1, 95% CI:1.4-3.0, p < 0.0001. There was a significantly larger proportion of under-represented minority faculty in EM residency programs (19.7%; 786/3,978) vs. EMS fellowships (12.0%, 33/274), OR = 1.8, 95% CI:1.2-2.6, p < 0.002. Conclusion: A significant number of EMS fellowship positions have remained unfilled since implementation of an accreditation process for EMS fellowships. The percentage of females and under-represented minority faculty in EMS programs was much lower than for EM residency programs.

Willingness of Emergency Medical Services Professionals to Respond to an Active Shooter Incident.

BACKGROUND: Historically, staging of civilian emergency medical services (EMS) during an active shooter incident was in the cold zone while these professionals awaited the scene to be completely secured by multiple waves of law enforcement. This delay in EMS response has led to the development of a more effective method: the Rescue Task Force (RTF). The RTF concept has the second wave of law enforcement escorting civilian EMS into the warm zone, thus decreasing EMS response time. To our knowledge, there are no data regarding the willingness of EMS professionals to enter a warm zone as part of an RTF. In this study, we assessed the willingness of EMS providers to respond to an active shooter incident as part of an RTF. METHODS: A survey was distributed at an annual, educational EMS conference in North Carolina. The surveys were distributed on the first day of the conference at the beginning of a general session that focused on EMS stress and wellness. Total attendance was measured using identification badges and scanners on exiting the session. Data were assessed using χ2 analysis, as were associations between demographics of interest and willingness to respond under certain conditions. A p value < .01 indicated statistical significance. RESULTS: The overall response rate was 76% (n = 391 of 515 session attendees). Most surveys were completed by paramedics (74%; n = 288 of 391). Most EMS professionals (75%; n = 293 of 391) stated they would respond to the given active shooter scenario as part of an RTF (escorted by the second wave of law enforcement) if they were given only ballistic gear. However, most EMS professionals (61%; n = 239 of 391) stated they would not respond if they were provided no ballistic gear and no firearm. Those with tactical or military training were more willing to respond with no ballistic gear and no firearm (49.6%; n = 68 of 137) versus those without such training (31%; n = 79 of 250; odds ratio, 2.2; 95% confidence interval, 1.4-3.3; p < .001). CONCLUSION: EMS professionals are willing to put themselves in harm's way by entering a warm zone if they are simply provided the proper training and ballistic equipment.

Poor extraction efficiencies of polystyrene nano- and microplastics from biosolids and soil.

Extraction and quantification of nano- and microplastics from sediments and soils is challenging. Although no standard method has been established so far, flotation is commonly used to separate plastic from mineral material. The objective of this study was to test the efficiency of flotation for the extraction of nano- and microplastics from biosolids and soil. We spiked biosolids and soil samples with polystyrene nano- and microbeads (0.05, 1.0, 2.6, 4.8, and 100 µm diameter). Different extraction methods (w/ and w/o H2O2 digestion) were tested, and plastic beads were separated from mineral particles by flotation in a ZnCl2 solution. Plastic particles were quantified by UV-Vis spectrometry and gravimetrically. While large beads (100 µm) could be quantitatively extracted (∼100%) from both biosolids and soils, smaller beads had low extraction efficiencies (ranging from 5 to 80%, with an average of 20%). Except for the 100 µm beads, oxidation with H2O2 negatively impacted the extraction efficiencies. For the soil, extraction with water only, followed by flotation in a ZnCl2 solution, resulted in relatively high extraction efficiencies (>75%) for beads larger than 1 µm, but low efficiencies (<30%) for the 0.05 and 1.0 µm beads. Our results indicate that while flotation generally works to separate plastic nano- and microbeads in a solution, the challenge is to quantitatively extract nano- and microbeads from a biosolids or soil matrix. Samples high in organic matter content require removal of the organic matter, but the common method of H2O2 oxidation leads to poor extraction efficiencies for nano- and microbeads.

Comparison Of The I-Gel Supraglottic And King Laryngotracheal Airways In A Simulated Tactical Environment.

BACKGROUND: When working in a tactical environment there are several different airway management options that exist. One published manuscript suggests that when compared to endotracheal intubation, the King LT laryngotracheal airway (KA) device minimizes time to successful tube placement and minimizes exposure in a tactical environment. However, comparison of two different blind insertion supraglottic airway devices in a tactical environment has not been performed. This study compared the I-Gel airway (IGA) to the KA in a simulated tactical environment, to determine if one device is superior in minimizing exposure and minimizing time to successful tube placement. METHODS: This prospective randomized cross over trial was performed using the same methods and tactical environment employed in a previously published study, which compared endotracheal intubation versus the KA in a tactical environment. The tactical environment was simulated with a one-foot vertical barrier. The participants were paramedic students who wore an Advanced Combat Helmet (ACH) and a ballistic vest (IIIA) during the study. Participants were then randomized to perform tactical airway management on an airway manikin with either the KA or the IGA, and then again using the alternate device. The participants performed a low military type crawl and remained in this low position during each tube placement. We evaluated the time to successful tube placement between the IGA and KA. During attempts, participants were videotaped to monitor their height exposure above the barrier. Following completion, participants were asked which airway device they preferred. Data was analyzed using Student's t-test across the groups for time to ventilation and height of exposure. RESULTS: In total 19 paramedic students who were already at the basic EMT level participated. Time to successful placement for the KA was 39.7 seconds (95%CI: 32.7-46.7) versus 14.4 seconds (95%CI: 12.0-16.9) for the IGA, p < 0.001. Maximum height exposure of the helmet above a one foot vertical barrier for the KA resulted in 1.42 inches of exposure (95%CI: 0.38-0.63) compared to the IGA with 1.42 inches, 95%CI:0.32-0.74, p = 0.99. On questioning 100% of the participants preferred the IGA device over the KA. CONCLUSION: In a simulated tactical environment placement of the IGA for airway management was faster than with the KA, but there was no difference in regard to exposure. Additionally, all the participants preferred using the IGA device over the KA.

Probability of a shockable presenting rhythm as a function of EMS response time.

INTRODUCTION: Survival from cardiac arrest is associated with having a shockable presenting rhythm (VF/pulseless VT) upon EMS arrival. A concern is that several studies have reported a decline in the incidence of VF/PVT over the past few decades. One plausible explanation is that contemporary cardiovascular therapies, such as increased use of statin and beta blocker drugs, may shorten the duration of VF/PVT after arrest. As a result, EMS response time would become an increasingly important factor in the likelihood of a shockable presenting rhythm, and consequently, cardiac arrest survival. OBJECTIVE: To develop a model describing the likelihood of shockable presenting rhythm as a function of EMS response time. METHODS: We conducted a retrospective observational study of cardiac arrest using the North Carolina Prehospital Care Reporting System (PreMIS). Inclusionary criteria consisted of adult patients suffering nontraumatic cardiac arrests witnessed by a layperson between January 1 and June 30, 2012. Patients defibrillated prior to EMS arrival were excluded. Chi-square and t-tests were used to analyze the relationship between shockable presenting rhythm and patient age, gender, and race; response time measured as elapsed minutes between 9-1-1 call receipt and scene arrival; and bystander CPR. Logistic regression was used to calculate the adjusted odds ratio (OR) of shockable presenting rhythm as a function of response time while controlling for statistically significant covariates. RESULTS: A total of 599 patients met inclusion criteria. Overall, VF/PVT was observed in 159 patients (26.5%). VF/PVT was less likely with increasing EMS response time (OR 0.92, 95% CI = 0.87-0.97, p < 0.01) and age (OR 0.98, 95% CI = 0.97-0.99, p < 0.01), while males (OR 1.98, 95% CI = 1.29-3.03, p < 0.01) and Caucasians (OR 1.86, 95% CI = 1.17-2.95, p < 0.01) were more likely to have shockable presenting rhythm. Bystander CPR was not associated with shockable presenting rhythm, although EMS response time was longer among patients with bystander CPR compared to those without (9.83 vs. 8.83 minutes, p < 0.01). CONCLUSIONS: We found that for every one minute of added ambulance response time, the odds of shockable presenting rhythm declined by 8%. This information could prove useful for EMS managers tasked with developing EMS system response strategies for cardiac arrest management.

Humanized mice as a model to study human hematopoietic stem cell transplantation.

Hematopoietic stem cell (HSC) transplantation has the potential to treat a variety of human diseases, including genetic deficiencies, immune disorders, and to restore immunity following cancer treatment. However, there are several obstacles that prevent effective HSC transplantation in humans. These include finding a matched donor, having a sufficient number of cells for the transplant, and the potency of the cells in the transplant. Ethical issues prevent effective research in humans that could provide insight into ways to overcome these obstacles. Highly immunodeficient mice can be transplanted with human HSCs and this process is accompanied by HSC homing to the murine bone marrow. This is followed by stem cell expansion, multilineage hematopoiesis, long-term engraftment, and functional human antibody and cellular immune responses. As such, humanized mice serve as a model for human HSC transplantation. A variety of conditions have been analyzed for their impact on HSC transplantation to produce humanized mice, including the type and source of cells used in the transplant, the number of cells transplanted, the expansion of cells with various protocols, and the route of introduction of cells into the mouse. In this review, we summarize what has been learned about HSC transplantation using humanized mice as a recipient model and we comment on how these models may be useful to future preclinical research to determine more effective ways to expand HSCs and to determine their repopulating potential in vivo.