Load Sharing in Gravel Decked Log Stringer Bridges

Log bridges are an economical alternative to steel and concrete structures for temporary crossings; however, reduced availability of large logs for stringers and the advancing age of existing log bridges increases the importance of structural analysis. Load sharing between the stringers is complicated and can result from load spread due to the gravel deck, cable lashing, and mechanical interlocking and friction between the stringers. This paper describes the development of a finite element model (FEM) for gravel decked log stringer bridges that includes elements capable of transferring vertical loads between the stringers. The FEM was used to interpret load deflection data from two in-situ bridges. The results of this paper suggest the segments of lashing that pass under one stringer and over an adjacent stringer contribute to load sharing between the stringers; however, care must be taken to ensure that the pattern of lashing supports the stringers directly loaded by the live loads

Lethal marine snow : pathogen of bivalve mollusc concealed in marine aggregates

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of American Society of Limnology and Oceanography for personal use, not for redistribution. The definitive version was published in Limnology and Oceanography 50 (2005): 1983-1988, doi:10.4319/lo.2005.50.6.1983.We evaluated marine aggregates as environmental reservoirs for a thraustochytrid pathogen, Quahog Parasite Unknown (QPX), of the northern quahog or hard clam, Mercenaria mercenaria. Positive results from in situ hybridization and denaturing gradient gel electrophoresis confirm the presence of QPX in marine aggregates collected from coastal embayments in Cape Cod, Massachusetts, where QPX outbreaks have occurred. In laboratory experiments, aggregates were observed and recorded by entering a quahog’s pallial cavity, thereby delivering embedded particles from the water column to its benthic bivalve host. The occurrence of pathogen-laden aggregates in coastal areas experiencing repeated disease outbreaks suggests a means for the spread and survival of pathogens between epidemics and provides a specific target for environmental monitoring of those pathogens.This work was funded by an NSF grant as part of the joint NSF-NIH Ecology of Infectious Disease program, by the Woods Hole Oceanographic Institution (WHOI) Sea Grant Program, under a grant from the National Oceanic and Atmospheric Administration, U.S. Department of Commerce, and a National Science Foundation Graduate Fellowship to M. Lyons

Network analysis of differential Ras isoform mutation effects on intestinal epithelial responses to TNF-α

Tumor necrosis factor alpha (TNF-α) is an inflammatory cytokine that can elicit distinct cellular behaviors under different molecular contexts. Mitogen activated protein kinase (MAPK) pathways, especially the extracellular signal-regulated kinase (Erk) pathway, help to integrate influences from the environmental context, and therefore modulate the phenotypic effect of TNF-α exposure. To test how variations in flux through the Erk pathway modulate TNF-α-elicited phenotypes in a complex physiological environment, we exposed mice with different Ras mutations (K-Ras activation, N-Ras activation, and N-Ras ablation) to TNF-α and observed phenotypic and signaling changes in the intestinal epithelium. Hyperactivation of Mek1, an Erk kinase, was observed in the intestine of mice with K-Ras activation and, surprisingly, in N-Ras null mice. Nevertheless, these similar Mek1 outputs did not give rise to the same phenotype, as N-Ras null intestine was hypersensitive to TNF-α-induced intestinal cell death while K-Ras mutant intestine was not. A systems biology approach applied to sample the network state revealed that the signaling contexts presented by these two Ras isoform mutations were different. Consistent with our experimental data, N-Ras ablation induced a signaling network state that was mathematically predicted to be pro-death, while K-Ras activation did not. Further modeling by constrained Fuzzy Logic (cFL) revealed that N-Ras and K-Ras activate the signaling network with different downstream distributions and dynamics, with N-Ras effects being more transient and diverted more towards PI3K-Akt signaling and K-Ras effects being more sustained and broadly activating many pathways. Our study highlights the necessity to consider both environmental and genomic contexts of signaling pathway activation in dictating phenotypic responses, and demonstrates how modeling can provide insight into complex in vivo biological mechanisms, such as the complex interplay between K-Ras and N-Ras in their downstream effects.National Institute of General Medical Sciences (U.S.) (Grant R01-GM088827)National Cancer Institute (U.S.) (U54-CA112967)United States. Army Research Office (Institute for Collaborative Biotechnologies Grant W911NF-09-D-000

Perspectives of older adults on co-management of low back pain by doctors of chiropractic and family medicine physicians: a focus group study.

BACKGROUND: While older adults may seek care for low back pain (LBP) from both medical doctors (MDs) and doctors of chiropractic (DCs), co-management between these providers is uncommon. The purposes of this study were to describe the preferences of older adults for LBP co-management by MDs and DCs and to identify their concerns for receiving care under such a treatment model. METHODS: We conducted 10 focus groups with 48 older adults who received LBP care in the past year. Interviews explored participants\u27 care seeking experiences, co-management preferences, and perceived challenges to successful implementation of a MD-DC co-management model. We analyzed the qualitative data using thematic content analysis. RESULTS: Older adults considered LBP co-management by MDs and DCs a positive approach as the professions have complementary strengths. Participants wanted providers who worked in a co-management model to talk openly and honestly about LBP, offer clear and consistent recommendations about treatment, and provide individualized care. Facilitators of MD-DC co-management included collegial relationships between providers, arrangements between doctors to support interdisciplinary referral, computer systems that allowed exchange of health information between clinics, and practice settings where providers worked in one location. Perceived barriers to the co-management of LBP included the financial costs associated with receiving care from multiple providers concurrently, duplication of tests or imaging, scheduling and transportation problems, and potential side effects of medication and chiropractic care. A few participants expressed concern that some providers would not support a patient-preferred co-managed care model. CONCLUSIONS: Older adults are interested in receiving LBP treatment co-managed by MDs and DCs. Older adults considered patient-centered communication, collegial interdisciplinary interactions between these providers, and administrative supports such as scheduling systems and health record sharing as key components for successful LBP co-management

Surface Water Intrusion, Land Use Impacts, and Bacterial Community Composition in Shallow Groundwater Wells Supplying Potable Water in Sparsely Populated Areas of a Boreal Region

Rural communities often rely on groundwater for potable water supply. In this study, untreated groundwater samples from 28 shallow groundwater wells in Finland ( IMPORTANCE Standard physicochemical water quality analyses and microbial indicator analyses leave much of the (largely uncultured) complexity of groundwater microbial communities unexplored. This study combined these standard methods with additional analyses of stable water isotopes, bacterial community data, and environmental data about the surrounding areas to investigate the associations between physicochemical and microbial properties of 28 shallow groundwater wells in Finland. We detected impaired groundwater quality in some wells, identified potential land use impacts, and revealed indications of surface water intrusion which were negatively correlated with bacterial alpha diversity. The potential influence of surface water intrusion on groundwater wells and their bacterial communities is of particular interest and warrants further investigation because surface water intrusion has previously been linked to groundwater contamination, which is the primary cause of waterborne outbreaks in the Nordic region and one of the major causes in the United States and Canada.Peer reviewe

Monitoring groundwater quality with real-time data, stable water isotopes, and microbial community analysis : A comparison with conventional methods

Groundwater provides much of the world's potable water. Nevertheless, groundwater quality monitoring programmes often rely on a sporadic, slow, and narrowly focused combination of periodic manual sampling and laboratory analyses, such that some water quality deficiencies go undetected, or are detected too late to prevent adverse consequences. In an effort to address this shortcoming, we conducted enhanced monitoring of untreated groundwater quality over 12 months (February 2019-February 2020) in four shallow wells supplying potable water in Finland. We supplemented periodic manual sampling and laboratory analyses with (i) real-time online monitoring of physicochemical and hydrological parameters, (ii) analysis of stable water isotopes from groundwater and nearby surface waters, and (iii) microbial community analysis of groundwater via amplicon sequencing of the 16S rRNA gene and 16S rRNA. We also developed an early warning system (EWS) for detecting water quality anomalies by automating real-time online monitoring data collection, transfer, and analysis - using electrical conductivity (EC) and turbidity as indirect water quality indicators. Real-time online monitoring measurements were largely in fair agreement with periodic manual measurements, demonstrating their usefulness for monitoring water quality; and the findings of conventional monitoring, stable water isotopes, and microbial community analysis revealed indications of surface water intrusion and faecal contamination at some of the studied sites. With further advances in technology and affordability expected into the future, the supplementary methods used here could be more widely implemented to enhance groundwater quality monitoring - by contributing new insights and/or corroborating the findings of conventional analyses.Peer reviewe

Sepsis prediction for the general ward setting

OBJECTIVE: To develop and evaluate a sepsis prediction model for the general ward setting and extend the evaluation through a novel pseudo-prospective trial design. DESIGN: Retrospective analysis of data extracted from electronic health records (EHR). SETTING: Single, tertiary-care academic medical center in St. Louis, MO, USA. PATIENTS: Adult, non-surgical inpatients admitted between January 1, 2012 and June 1, 2019. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 70,034 included patient encounters, 3.1% were septic based on the Sepsis-3 criteria. Features were generated from the EHR data and were used to develop a machine learning model to predict sepsis 6-h ahead of onset. The best performing model had an Area Under the Receiver Operating Characteristic curve (AUROC or c-statistic) of 0.862 ± 0.011 and Area Under the Precision-Recall Curve (AUPRC) of 0.294 ± 0.021 compared to that of Logistic Regression (0.857 ± 0.008 and 0.256 ± 0.024) and NEWS 2 (0.699 ± 0.012 and 0.092 ± 0.009). In the pseudo-prospective trial, 388 (69.7%) septic patients were alerted on with a specificity of 81.4%. Within 24 h of crossing the alert threshold, 20.9% had a sepsis-related event occur. CONCLUSIONS: A machine learning model capable of predicting sepsis in the general ward setting was developed using the EHR data. The pseudo-prospective trial provided a more realistic estimation of implemented performance and demonstrated a 29.1% Positive Predictive Value (PPV) for sepsis-related intervention or outcome within 48 h

Exercise-Based Stroke Rehabilitation: Clinical Considerations Following the COVID-19 Pandemic

Background. The COVID-19 pandemic attributable to the severe acute respiratory syndrome virus (SARS-CoV-2) has had a significant and continuing impact across all areas of healthcare including stroke. Individuals post-stroke are at high risk for infection, disease severity, and mortality after COVID-19 infection. Exercise stroke rehabilitation programs remain critical for individuals recovering from stroke to mitigate risk factors and morbidity associated with the potential long-term consequences of COVID-19. There is currently no exercise rehabilitation guidance for people post-stroke with a history of COVID-19 infection. Purpose. To (1) review the multi-system pathophysiology of COVID-19 related to stroke and exercise; (2) discuss the multi-system benefits of exercise for individuals post-stroke with suspected or confirmed COVID-19 infection; and (3) provide clinical considerations related to COVID-19 for exercise during stroke rehabilitation. This article is intended for healthcare professionals involved in the implementation of exercise rehabilitation for individuals post-stroke who have suspected or confirmed COVID-19 infection and non-infected individuals who want to receive safe exercise rehabilitation. Results. Our clinical considerations integrate pre-COVID-19 stroke (n = 2) and COVID-19 exercise guidelines for non-stroke populations (athletic [n = 6], pulmonary [n = 1], cardiac [n = 2]), COVID-19 pathophysiology literature, considerations of stroke rehabilitation practices, and exercise physiology principles. A clinical decision-making tool for COVID-19 screening and eligibility for stroke exercise rehabilitation is provided, along with key subjective and physiological measures to guide exercise prescription. Conclusion. We propose that this framework promotes safe exercise programming within stroke rehabilitation for COVID-19 and future infectious disease outbreaks