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Rivers play a major role in the distribution of microplastics (MPs) in the environment, however, research on temporal variations in these highly dynamic systems is still in its infancy. To date, most studies dealing with the seasonality of MP contamination in rivers focus on bi-yearly analysis, while temporal fluctuations over the course of the year are rarely studied. To shed more light on seasonal variability of MP abundance and potential driving factors, we have thus sampled the water surface of one location in the Weser River in Germany monthly over one entire year. In our study, we targeted MP in the size range 10-5000 μm, using two different state-of-the-art sampling methods (manta net for large MP (l-MP; 500-5000 μm) and a filtration system for small MP (s-MP; 10-500 μm)) and analysis techniques (ATR-FTIR and FPA-μFTIR) for chemical identification. Our findings show a strong size-dependent positive correlation of the MP concentration with discharge rates (specifically direct runoff) and suspended particulate matter (SPM) for s-MPs, specifically in the size range 10-149 μm. L-MPs, however, show a different environmental behaviour and do not follow these patterns. With our study, we were able to deliver a much higher temporal resolution, covering a broader size range of MPs compared to most studies. Our findings point towards an interplay of two possible mechanisms: a) the riverbeds play an important role in large-scale MP and SPM release via resuspension during high discharge events, and b) precipitation-driven soil erosion and runoff from urban surfaces (e.g. rain sewers) introduce MP and SPM. Hence, our study serves as a basis for more detailed investigations of MP transport in and between ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

One of the biggest issues in microplastic (MP, plastic items  <5 mm) research is the lack of standardisation and harmonisation in all fields, reaching from sampling methodology to sample purification, analytical methods and data analysis. This hampers comparability as well as reproducibility among studies. Concerning chemical analysis of MPs, Fourier-transform infrared (FTIR) spectroscocopy is one of the most powerful tools. Here, focal plane array (FPA) based micro-FTIR (µFTIR) imaging allows for rapid measurement and identification without manual preselection of putative MP and therefore enables large sample throughputs with high spatial resolution. The resulting huge datasets necessitate automated algorithms for data analysis in a reasonable time frame. Although solutions are available, little is known about the comparability or the level of reliability of their output. For the first time, within our study, we compare two well-established and frequently applied data analysis algorithms in regard to results in abundance, polymer composition and size distributions of MP (11-500 µm) derived from selected environmental water samples: (a) the siMPle analysis tool (systematic identification of MicroPlastics in the environment) in combination with MPAPP (MicroPlastic Automated Particle/fibre analysis Pipeline) and (b) the BPF (Bayreuth Particle Finder). The results of our comparison show an overall good accordance but also indicate discrepancies concerning certain polymer types/clusters as well as the smallest MP size classes. Our study further demonstrates that a detailed comparison of MP algorithms is an essential prerequisite for a better comparability of MP data., (© 2023. The Author(s).)

Background: Advanced practice registered nurses (APRNs) and physician assistants (PAs) are integral to health care delivery in the United States. However, the cultivation of APRNs and PAs relies heavily on the model of precepting. Advanced practice registered nurses and PAs frequently precept students or new hires, yet limited data are available to describe the motivations, incentives, and barriers associated with precepting., Purpose: The purpose of this mixed-method, cross-sectional study was to better understand APRN and PA preceptors' perceived levels of support during precepting, facilitating factors, and barriers to the precepting process., Methods: An electronic survey was distributed via REDCap to a convenience sample of APRN and PA preceptors at an academic medical center. Data collected from the survey were analyzed using both descriptive statistics and qualitative thematic analysis., Results: One hundred fifty-four participants completed the survey. Motivating factors for precepting included "giving back" to the profession, and barriers included inadequate time to precept while in the clinical role. Participants indicated that financial incentives, heightened communication, protected teaching time, preceptor training, meaningful recognition, and organizational support could enhance the precepting process., Conclusion: This study demonstrated that altruistic intentions frequently motivate APRN and PA preceptors, however, navigating multiple clinical responsibilities while precepting serves as a barrier to the precepting process. Preceptor training, ongoing education, dedicated time for precepting, enhanced communication, and organizational or professional incentives may optimize the APRN and PA precepting process., Implications: Further research should focus on how to optimally incorporate education, professional development, support, and incentives into the APRN and PA preceptor role., Competing Interests: Competing interests: The authors report no conflicts of interest., (Copyright © 2022 American Association of Nurse Practitioners.)

Microplastic (MP) appears to be omnipresent in the atmosphere, raising concerns about dispersion across environmental compartments, ecological consequences and human health risks by inhalation. To date, data on the sources of atmospheric MP and deposition to river catchment areas are still sparse. We, therefore, took aerosol and total atmospheric deposition samples in the catchment area of the large German river Weser to estimate microplastic deposition fluxes (DFs) at six specific sites and airborne MP concentrations. Sampling in rural, suburban, and urban environments and wastewater treatment plants (WWTPs) was performed, aiming at a variation in airborne MP pollution and elucidating potential MP source areas. Aerosol samples were taken twice in April and October while monthly total deposition samples were collected over a period from March to October. Microplastics were detected in all analysed aerosol samples by Raman spectroscopy down to 4 μm, and in all 32 total deposition samples by μFT-IR down to 11 μm. Average MP number concentrations of 91 ± 47 m -3 were found in aerosol samples. The measured total MP number DFs ranged between 10 and 367 N m -2  day -1 (99 ± 85 mean ± SD) corresponding to total deposition of 0.05 ± 0.1 kg ha -1 per year and to an estimated 232 metric tons of plastic being deposited in the Weser River catchment annually. MP number DFs were higher in urban than rural sites. An effect of WWTPs on the MP abundance in air was not observed. Polypropylene, polyethylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, and silicone fragments were found as the predominant polymer types in total deposition samples, while polyethylene particles dominated in aerosol samples. The results suggest that proximity to sources, especially to cities, increase the numbers of MP found in the atmosphere. It further indicates that atmospheric MP considerably contributes to the contamination of both aquatic and terrestrial habitats., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Traumatic brain injury (TBI) is often accompanied by hemorrhage, and treatment of hemorrhagic shock (HS) after TBI is particularly challenging because the two therapeutic treatment strategies for TBI and HS often conflict. Ischemia/reperfusion injury from HS resuscitation can be exaggerated by TBI-induced loss of autoregulation. In HS resuscitation, the goal is to restore lost blood volume, while in the treatment of TBI the priority is focused on maintenance of adequate cerebral perfusion pressure and avoidance of secondary bleeding. In this study, we investigate the responses to resuscitation from severe HS after TBI in rats, using fresh blood, polymerized human hemoglobin (PolyhHb), and lactated Ringer's (LR). Rats were subjected to TBI by pneumatic controlled cortical impact. Shortly after TBI, HS was induced by blood withdrawal to reduce mean arterial pressure (MAP) to 35-40 mmHg for 90 min before resuscitation. Resuscitation fluids were delivered to restore MAP to ~ 65 mmHg and animals were monitored for 120 min. Increased systolic blood pressure variability (SBPV) confirmed TBI-induced loss of autoregulation. MAP after resuscitation was significantly higher in the blood and PolyhHb groups compared to the LR group. Furthermore, blood and PolyhHb restored diastolic pressure, while this remained depressed for the LR group, indicating a loss of vascular tone. Lactate increased in all groups during HS, and only returned to baseline level in the blood reperfused group. The PolyhHb group possessed lower SBPV compared to LR and blood groups. Finally, sympathetic nervous system (SNS) modulation was higher for the LR group and lower for the PolyhHb group compared to the blood group after reperfusion. In conclusion, our results suggest that PolyhHb could be an alternative to blood for resuscitation from HS after TBI when blood is not available, assuming additional testing demonstrate similar favorable results. PolyhHb restored hemodynamics and oxygen delivery, without the logistical constraints of refrigerated blood.

To understand how the microvasculature grows and remodels, researchers require reproducible systems that emulate the function of living tissue. Innovative contributions toward fulfilling this important need have been made by engineered microvessels assembled in vitro with microfabrication techniques. Microfabricated vessels, commonly referred to as "vessels-on-a-chip," are from a class of cell culture technologies that uniquely integrate microscale flow phenomena, tissue-level biomolecular transport, cell-cell interactions, and proper three-dimensional (3-D) extracellular matrix environments under well-defined culture conditions. Here, we discuss the enabling attributes of microfabricated vessels that make these models more physiological compared with established cell culture techniques and the potential of these models for advancing microvascular research. This review highlights the key features of microvascular transport and physiology, critically discusses the strengths and limitations of different microfabrication strategies for studying the microvasculature, and provides a perspective on current challenges and future opportunities for vessel-on-a-chip models.

Background: Pacific walruses ( Odobenus rosmarus divergens ) are a conspicuous and important component of the Bristol Bay ecosystem and human social systems, but very little is known about walrus ecology in this region, principally their feeding ecology. The present work provides contemporary data on the diets of walruses at four haulout locations throughout Bristol Bay between 2014 and 2018., Methods: We analyzed scat and gastrointestinal tract samples from these animals using quantitative polymerase chain reaction to amplify prey DNA, which allowed for diet estimates based on frequencies of prey item occurrence and on the relative importance of dietary items as determined from DNA threshold cycle scores., Results: Diets were highly diverse at all locations, but with some variation in composition that may be related to the time of year that samples were collected (summer vs. autumn), or to spatial variability in the distribution of prey. Overall, polychaetes and tunicates had the highest frequencies of occurrence and relative abundances in 2014-15, but a major change in diet appears to have occurred by 2017-18. While some sample sizes were small, diets in these later years contrasted sharply, with a greater prevalence of sea cucumbers and mollusks, and reduced importance of decapods and fishes compared to the earlier years. Prey identified in scat samples from one collection site also contrasted sharply with those reported from the same location in 1981. The apparent temporal shifts in walrus prey may represent a changing benthic ecosystem due to warming waters in recent decades., Competing Interests: John M. Maniscalco, Katrina Counihan and Tuula Hollmen are employed by Alaska SeaLife Center, and Helen M. Aderman and Moses Toyukak, Sr. are affiliated with the Bristol Bay Native Association., (©2020 Maniscalco et al.)