1,626 research outputs found
Evaluation of crack sealing techniques in Alaska's asphalt concrete pavements
Thesis (Ph.D.) University of Alaska Fairbanks, 2016Thermal cracking is one of the most prevalent asphalt concrete (AC) pavement distresses in northern states and countries. Every year in Alaska, a substantial amount of funding is spent on sealing cracks according to the practices of the Alaska Department of Transportation and Public Facilities (ADOT&PF) Maintenance and Operations (M&O) division. However, to date there are no specific guidelines available that clearly outline the best timing for crack sealing or even what conditions necessitate crack sealing in a consistent manner. There is a need to evaluate the effectiveness and best practices for using the crack sealing techniques on AC pavements in Alaska. In response to this research need, a pavement preservation project was conducted and found that although crack sealing is a very common practice in Alaska, it is unclear how and why M&O decides to seal cracks since some are sealed and some are not. This motivated further evaluation of 91 field sections that represent the various climate regions of Alaska. A new survey method, "special thermal crack evaluation (STCE) ", was developed to answer critical questions related to road thermal cracks and to provide guidance for crack sealing practices. The new STCE method was conducted along with two other field survey methods, the Long Term Pavement Performance (LTPP) program and the Pavement Surface and Evaluation Rating (PASER). Results between methods were then correlated. Finally, regression analyses were conducted to determine factors that significantly influence crack development and crack sealing practices in Alaska. Significant influencing factors on crack development include pavement temperature, freezing index, and rut depth. Crack frequency, freezing index, pavement age, PASER rating, PASER transverse crack severity level, and certain STCE questions can significantly contribute to the decision making for current sealing practices. It was found that the STCE method could generate direct recommendations on crack sealing practices. STCE, in combination with the LTPP and PASER methods, provides specific analysis about asphalt thermal cracking and sealing of these cracks so that informed decisions can be made for a positive impact on ADOT&PF's maintenance budget. It is recommended to use STCE along with the LTPP and PASER methods and to use the findings of influencing factors of this study to develop more specific plans for future crack sealing practices
Handheld Raman Spectroscopy in the First UK Home Office Licensed Pharmacist-Led Community Drug Checking Service
© 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).Across the world, the interest in point-of-care drug checking as a harm-reduction intervention is growing. This is an attempt to improve intelligence about current drug trends and reduce drug-related morbidity and mortality. In the UK, drug-related harm is increasing exponentially year after year. As such, specialist community treatment services are exploring new methods to improve engagement with people who use drugs (PWUD), who may require support for their problematic drug use. This need has driven the requirement to pilot an on-site, time-responsive, readily available drug-checking service at point-of-support centres. In this study, we piloted the UKâs first Home Office-licensed drug-checking service that was embedded into a community substance-misuse service and had all on-site analysis and harm-reduction interventions led and delivered by pharmacists. We report on the laboratory findings from the associated confirmatory analysis (UHPLC-MS, GC-MS, and 1H NMR) to assess the performance of the on-site hand-held Raman spectrometer and outline the challenges of providing real-time analysis of psychoactive substances in a clinical setting. Whilst acknowledging the limitation of the small sample size (n = 13), we demonstrate the potential suitability of using this technology for the purposes of screening substances in community-treatment services. Portability of equipment and timeliness of results are important and only very small samples may be provided by people who use the service. The challenges of accurately identifying substances from complex mixtures were equally found with both point-of-care Raman spectroscopy and laboratory confirmatory-analysis techniques. Further studies are required to confirm these findings.Peer reviewe
Quantitative histopathologic assessment of perfusion MRI as a marker of glioblastoma cell infiltration in and beyond the peritumoral edema region
Background:
Conventional MRI fails to detect regions of glioblastoma cell infiltration beyond the contrastâenhanced T1 solid tumor region, with infiltrating tumor cells often migrating along host blood vessels.
Purpose:
To quantitatively and qualitatively analyze the correlation between perfusion MRI signal and tumor cell density in order to assess whether local perfusion perturbation could provide a useful biomarker of glioblastoma cell infiltration.
Study Type:
Animal model.
Subjects:
Mice bearing orthotopic glioblastoma xenografts generated from a patientâderived glioblastoma cell line.
Field Strength/Sequences:
7T perfusion images acquired using a high signalâtoânoise ratio (SNR) multiple boli arterial spin labeling sequence were compared with conventional MRI (T1/T2 weighted, contrastâenhanced T1, diffusionâweighted, and apparent diffusion coefficient).
Assessment:
Immunohistochemistry sections were stained for human leukocyte antigen (probing humanâderived tumor cells). To achieve quantitative MRIâtissue comparison, multiple histological slices cut in the MRI plane were stacked to produce tumor cell density maps acting as a âground truth.â
Statistical Tests:
Sensitivity, specificity, accuracy, and Dice similarity indices were calculated and a twoâtailed, paired tâtest used for statistical analysis.
Results:
High comparison test results (Dice 0.62â0.72, Accuracy 0.86â0.88, Sensitivity 0.51â0.7, and Specificity 0.92â0.97) indicate a good segmentation for all imaging modalities and highlight the quality of the MRI tissue assessment protocol. Perfusion imaging exhibits higher sensitivity (0.7) than conventional MRI (0.51â0.61). MRI/histology voxelâtoâvoxel comparison revealed a negative correlation between tumor cell infiltration and perfusion at the tumor margins (Pâ=â0.0004).
Data Conclusion:
These results demonstrate the ability of perfusion imaging to probe regions of low tumor cell infiltration while confirming the sensitivity limitations of conventional imaging modalities. The quantitative relationship between tumor cell density and perfusion identified in and beyond the edematous T2 hyperintensity region surrounding macroscopic tumor could be used to detect marginal tumor cell infiltration with greater accuracy
Benzodiazepine Boom: Tracking Etizolam, Pyrazolam, and Flubromazepam from Pre-UK Psychoactive Act 2016 to Present Using Analytical and Social Listening Techniques
© 2024 The Author(s). Licensee MDPI, Basel, Switzerland. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Introduction: The designer benzodiazepine (DBZD) market continues to expand whilst evading regulatory controls. The widespread adoption of social media by pro-drug use communities encourages positive discussions around DBZD use/misuse, driving demand. This research addresses the evolution of three popular DBZDs, etizolam (E), flubromazepam (F), and pyrazolam (P), available on the drug market for over a decade, comparing the quantitative chemical analyses of tablet samples, purchased from the internet prior to the implementation of the Psychoactive Substances Act UK 2016, with the thematic netnographic analyses of social media content. Method: Drug samples were purchased from the internet in early 2016. The characterisation of all drug batches were performed using UHPLC-MS and supported with 1H NMR. In addition, netnographic studies across the platforms X (formerly Twitter) and Reddit, between 2016â2023, were conducted. The latter was supported by both manual and artificial intelligence (AI)-driven thematic analyses, using numerous.ai and ChatGPT, of social media threads and discussions. Results: UHPLC-MS confirmed the expected drug in every sample, showing remarkable inter/intra batch variability across all batches (E = 13.8 ± 0.6 to 24.7 ± 0.9 mg; F = 4.0 ± 0.2 to 23.5 ± 0.8 mg; P = 5.2 ± 0.2 to 11.5 ± 0.4 mg). 1H NMR could not confirm etizolam as a lone compound in any etizolam batch. Thematic analyses showed etizolam dominated social media discussions (59% of all posts), with 24.2% of posts involving sale/purchase and 17.8% detailing new administration trends/poly-drug use scenarios. Artificial intelligence confirmed three of the top five trends identified manually. Conclusions: Purity variability identified across all tested samples emphasises the increased potential health risks associated with DBZD consumption. We propose the global DBZD market is exacerbated by surface web social media discussions, recorded across X and Reddit. Despite the appearance of newer analogues, these three DBZDs remain prevalent and popularised. Reporting themes on harm/effects and new developments in poly-drug use trends, demand for DBZDs continues to grow, despite their potent nature and potential risk to life. It is proposed that greater controls and constant live monitoring of social media user content is warranted to drive active regulation strategies and targeted, effective, harm reduction strategies.Peer reviewe
Towards a multi-arm multi-stage platform trial of disease modifying approaches in Parkinson's disease
An increase in the efficiency of clinical trial conduct has been successfully demonstrated in the oncology field, by the use of multi-arm, multi-stage trials allowing the evaluation of multiple therapeutic candidates simultaneously, and seamless recruitment to phase 3 for those candidates passing an interim signal of efficacy. Replicating this complex innovative trial design in diseases such as Parkinsonâs disease is appealing, but in addition to the challenges associated with any trial assessing a single potentially disease modifying intervention in Parkinsonâs disease, a multi-arm platform trial must also specifically consider the heterogeneous nature of the disease, alongside the desire to potentially test multiple treatments with different mechanisms of action.
In a multi-arm trial, there is a need to appropriately stratify treatment arms to ensure each are comparable with a shared placebo/standard of care arm; however, in Parkinsonâs disease there may be a preference to enrich an arm with a subgroup of patients that may be most likely to respond to a specific treatment approach. The solution to this conundrum lies in having clearly defined criteria for inclusion in each treatment arm as well as an analysis plan that takes account of predefined subgroups of interest, alongside evaluating the impact of each treatment on the broader population of Parkinsonâs disease patients.
Beyond this, there must be robust processes of treatment selection, and consensus derived measures to confirm target engagement and interim assessments of efficacy, as well as consideration of the infrastructure needed to support recruitment, and the long-term funding and sustainability of the platform. This has to incorporate the diverse priorities of clinicians, triallists, regulatory authorities and above all the views of people with Parkinsonâs disease
Towards a multi-arm multi-stage platform trial of disease modifying approaches in Parkinson's disease
An increase in the efficiency of clinical trial conduct has been successfully demonstrated in the oncology field, by the use of multi-arm, multi-stage trials allowing the evaluation of multiple therapeutic candidates simultaneously, and seamless recruitment to Phase 3 for those candidates passing an interim signal of efficacy. Replicating this complex innovative trial design in diseases such as Parkinson's disease is appealing but in addition to the challenges associated with any trial assessing a single potentially disease modifying intervention in PD, a multi-arm platform trial must also specifically consider the heterogeneous nature of PD, alongside the desire to potentially test multiple treatments with different mechanisms of action. In a multi-arm trial, there is a need to appropriately stratify treatment arms to ensure each are comparable with a shared placebo/standard of care arm, however in PD there may be a preference to enrich an arm with a subgroup of patients that may be most likely to respond to a specific treatment approach. The solution to this conundrum lies in having clearly defined criteria for inclusion in each treatment arm as well as an analysis plan that takes account of pre-defined subgroups of interest, alongside evaluating the impact of each treatment on the broader population of PD patients. Beyond this, there must be robust processes of treatment selection, and consensus derived measures to confirm target engagement and interim assessments of efficacy, as well as consideration of the infrastructure needed to support recruitment, and the long-term funding and sustainability of the platform. This has to incorporate the diverse priorities of clinicians, triallists, regulatory authorities and above all the views of people with Parkinson's disease
A Comprehensive Predictive Corrosion Model incorporating varying Environmental Gas Pollutants applied to Wider Steel Applications
A comprehensive model has been developed to predict uniform corrosion rate of structural steel under the effect of low pH conditions for example acid rain. Acid rain is mainly caused by emissions of sulfur dioxide (SO2) which reacts with the water droplets in atmosphere to produce acidic solution which is the primary cause of corrosion of steel structures such as bridges, and weathering of stone buildings and statues. A five-stage division was applied to mathematically describe the model as: (i) the growth rate of air-suspended water droplets (i.e. moisture) depending on the condensation/evaporation rate, (ii) the absorption of gas phase SO2 in the droplets forming bisulfite HSO_3^- ions, (iii) the coalescence of these SO2 absorbed water droplets under the effects of wind speed and gravity, (iv) the deposition rate of SO2 absorbed droplets on steel substrate depending on the inclination and azimuth angles of steel surfaces and, (v) the corrosion rate of steel due to the deposition of these SO2 absorbed droplets. The incorporation of all the above stages develops a comprehensive corrosion prediction model which not only includes the electrochemical parameters but also large number of physical, environmental and material parameters. Experiment was performed to analyse the corrosion rate of steel samples by exposing them to moist SO2 corrosion test. A comparative analysis between the model predictions and experimental results was performed to verify the reliability of model. The predictive trends of corrosion rate of steel were also generated for different values of temperature, relative humidity, and SO2 mole percentage
Towards a multi-arm multi-stage platform trial of disease modifying approaches in Parkinsonâs disease
An increase in the efficiency of clinical trial conduct has been successfully demonstrated in the oncology field, by the use of multi-arm, multi-stage trials allowing the evaluation of multiple therapeutic candidates simultaneously, and seamless recruitment to phase 3 for those candidates passing an interim signal of efficacy. Replicating this complex innovative trial design in diseases such as Parkinsonâs disease is appealing, but in addition to the challenges associated with any trial assessing a single potentially disease modifying intervention in Parkinsonâs disease, a multiarm platform trial must also specifically consider the heterogeneous nature of the disease, alongside the desire to potentially test multiple treatments with different mechanisms of action. In a multi-arm trial, there is a need to appropriately stratify treatment arms to ensure each are comparable with a shared placebo/standard of care arm; however, in Parkinsonâs disease there may be a preference to enrich an arm with a subgroup of patients that may be most likely to respond to a specific treatment approach. The solution to this conundrum lies in having clearly defined criteria for inclusion in each treatment arm as well as an analysis plan that takes account of predefined subgroups of interest, alongside evaluating the impact of each treatment on the broader population of Parkinsonâs disease patients. Beyond this, there must be robust processes of treatment selection, and consensus derived measures to confirm target engagement and interim assessments of efficacy, as well as consideration of the infrastructure needed to support recruitment, and the long-term funding and sustainability of the platform. This has to incorporate the diverse priorities of clinicians, triallists, regulatory authorities and above all the views of people with Parkinsonâs disease.</p
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