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1.
Int J Dent ; 2024: 3783021, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38803464

RESUMO

Learning suturing skills is an important area of the undergraduate curriculum and ideally requires realistic and anatomically accurate surgical training models to prepare students for treating patients. Little is currently understood regarding which model might be perceived by students to be the best or which might most effectively facilitate their learning. The aim of this study was to compare four teaching models: a tabletop silicon dental model, a restricted access tabletop model, a traditional phantom head mounted model, and a Thiel cadaver. Student preferences were explored for each of the models. Following lecture and video-based teaching 67 fourth-year students attended a practical suturing teaching session followed by the second session more focused on the experience of cutting and suturing mucoperiosteal flaps. Forty-six students (67%) gave online anonymous feedback on the first session. The majority (95%) felt prepared to place a simple interrupted suture on a patient, and 88% felt confident to do so. Twenty-eight students (40%) provided feedback on the second session with 82% agreeing that they were prepared to cut a mucoperiosteal flap and 48% felt confident to do this for a patient. The cadaver model was rated as the best of the four models for both suturing and mucoperiosteal flap skills. These results support its use for teaching students to suturing and surgical skills. However, despite this teaching student-rated confidence to cut and suture flaps for a patient remains poor.

2.
Forensic Sci Med Pathol ; 20(1): 239-248, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36773212

RESUMO

This study aimed to systematically review the correlational accuracy between width ratios and length ratios based on the Kvaal methodology with chronological age. This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). The search strategy included ProQuest, PubMed, Science Direct, and Taylor and Francis and Willey online without time or language restriction using Kvaal method of age estimation as key words for the search up to December 2021. A team of two researchers independently selected the studies and extracted the data. The Covidence platform was used to systematically organize all titles. The full texts of eligible studies were analyzed. Risk of bias (RoB) was assessed using a modified (to the specific characteristics of this systematic review) checklist based on Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement checklist for observational studies. A total of 658 articles were initially reviewed, but 22 were selected for inclusion. The risk of bias was estimated to be unclear to low overall. Among the length ratios, ratio R showed a strong association with chronological age, followed by ratio P. For the width ratios, ratio B demonstrated a close association with chronological age, followed by ratio C. The results suggest that width ratios correlate better with chronological age than length ratios. This systematic review suggests the width ratios are more strongly associated with chronological age than the length ratios. Using a width ratio could serve as a convenient and rapid way to estimate dental age. Our results apply equally to all types of ethnic groups.


Assuntos
Viés , Humanos
3.
J Oral Biosci ; 66(1): 5-12, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38036053

RESUMO

BACKGROUND: In the absence of soft tissue, skeletal remains are analyzed to identify the deceased. This assessment involves establishing the biological profile that aids medicolegal investigations and fulfils the right of the dead to be identified. Since the mandible is the strongest bone in the skull and easily identifiable, even when fragmented, this study aimed to systematically review its value in constructing the biological profile in the published literature. We searched PubMed, ScienceDirect, Scopus, and Latin American and Caribbean Health Sciences Literature and collected cross-sectional studies published in English before 2021. A risk of bias assessment was completed based on Joanna Briggs Institute's critical appraisal tools. The data are presented descriptively and were analyzed using Microsoft Office Excel 365. HIGHLIGHT: Of the 104 eligible articles, 94 examined the sexual dimorphism of the mandible, while 25 attempted to estimate age. Ancestry and stature were the least explored biological characteristics (five and one articles, respectively). A metric analysis was the most common approach (n = 80), followed by morphological analysis and combined morphologic and metric techniques (n = 18 and n = 6, respectively). The results showed no statistically significant correlation between an individual's mandible and stature. Orthopantomogram radiography continues to be the most common radiographic technique for assessing the mandible. CONCLUSION: The mandible is reliable when used for sex estimation; however, caution should be exercised in relying solely on it for morphological assessments. This review provides guidance on estimating age, sex, and ancestry directly from mandibular specimens or radiographs.


Assuntos
Cabeça , Mandíbula , Humanos , Estudos Transversais , Mandíbula/diagnóstico por imagem , Mandíbula/anatomia & histologia , Radiografia , Caracteres Sexuais
4.
Opt Lett ; 48(18): 4857-4860, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37707921

RESUMO

Oral cancer, primarily oral squamous cell carcinomas (OSCC), is a major health concern worldwide. The current gold standard for the diagnosis of OSCC is biopsy and histopathological analysis, which is invasive and can place a huge financial burden on the healthcare system. Optical coherence tomography-based angiography (OCTA) is a non-invasive imaging technique that shows promise as an imaging modality to aid the diagnosis of OSCC. This Letter outlines the development of a handheld intraoral OCT probe applied to a swept-source OCT system with an angiography function for oral applications. The probe has a thin body with a diameter of 17.8 mm and a two-lens system with a working distance that is adjustable from 20.92 mm to 24.08 mm, a field of view 9 mm in diameter, an imaging depth of ∼1.7 mm, and resolutions of 39.38 µm (laterally) and 33.37 µm (axially). This probe was used to scan 14 oral sites to evaluate its ability to scan various sites in the oral cavity. This system has the potential to reduce invasive procedures and aid early OSCC diagnosis.


Assuntos
Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Humanos , Tomografia de Coerência Óptica , Angiografia , Neoplasias Bucais/diagnóstico por imagem , Carcinoma de Células Escamosas de Cabeça e Pescoço/diagnóstico por imagem
5.
Int J Legal Med ; 137(1): 123-130, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36197526

RESUMO

In adult dental age estimation, segmentation of dental volumetric information from different tooth parts using cone-beam computed tomography (CBCT) has proven beneficial in improving the regression model reliability. This segmentation method can be expanded in the crown part since the volumetric information in the crown is affected by attrition in the enamel and secondary dentine in the dentine and pulp chamber. CBCT scans from 99 patients aged between 20 and 60 were collected retrospectively. A total of 80 eligible teeth for each tooth type were used in this study. The enamel to dentine volume ratio (EDVR), pulp to dentine volume ratio (PDVR) and sex were used as independent variables to predict chronological age (CA). The EDVR was not affected by PDVR. The highest R2 was calculated from the maxillary canine (R2 = 0.6). The current approach in crown segmentation has proven to improve model performance in anterior maxillary teeth.


Assuntos
Determinação da Idade pelos Dentes , Tomografia Computadorizada de Feixe Cônico Espiral , Reprodutibilidade dos Testes , Estudos Retrospectivos , Determinação da Idade pelos Dentes/métodos , Odontologia Legal/métodos , Dente Canino/diagnóstico por imagem , Tomografia Computadorizada de Feixe Cônico , Coroas , Imageamento Tridimensional
6.
Dent J (Basel) ; 10(12)2022 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-36547045

RESUMO

BACKGROUND: The detrimental impact of the COVID-19 pandemic on dental education prompted the Scottish Government to fund an additional year to the dental course to ensure that the students had the necessary clinical experience. The aim of the study was to better understand the final year student perceptions of this extension on their oral surgery experience at the University of Dundee. METHODS: This mixed methods study consisted of an anonymous online questionnaire and a focus group. RESULTS: Forty-one students (69.3%) completed the questionnaire and ten students participated in the focus group. Thirty-six (88.8%) students agreed that the oral surgery teaching provided sufficient knowledge to undertake independent practice. All of the students felt confident to carry out an extraction, and the majority of them (n = 40, 95%) felt confident to remove a retained root, however, their confidence with surgery was lower. CONCLUSION: The extension gave the students sufficient experience in oral surgery to gain confidence in clinical skills and an appropriate level of knowledge in preparation for the next phase of their career. Most of the students agreed that the extension was necessary and beneficial. This cohort graduated with more oral surgery experience than any of the students did in the previous 4 years from Dundee and with experience that was comparable with the students at other schools in the pre-COVID-19 era.

7.
Geophys Res Lett ; 49(19): e2022GL100014, 2022 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-36582259

RESUMO

An interplanetary shock can abruptly compress the magnetosphere, excite magnetospheric waves and field-aligned currents, and cause a ground magnetic response known as a sudden commencement (SC). However, the transient (<∼1 min) response of the ionosphere-thermosphere system during an SC has been little studied due to limited temporal resolution in previous investigations. Here, we report observations of a global reversal of ionospheric vertical plasma motion during an SC on 24 October 2011 using ∼6 s resolution Super Dual Auroral Radar Network ground scatter data. The dayside ionosphere suddenly moved downward during the magnetospheric compression due to the SC, lasting for only ∼1 min before moving upward. By contrast, the post-midnight ionosphere briefly moved upward then moved downward during the SC. Simulations with a coupled geospace model suggest that the reversed E ⃗ × B ⃗ vertical drift is caused by a global reversal of ionospheric zonal electric field induced by magnetospheric compression during the SC.

8.
Front Psychol ; 13: 960638, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36312160

RESUMO

Lifestyle factors are known to be influential determinants of health. According to the World Health Organization (WHO), approximately one third of deaths involve unhealthy lifestyle habits. Among lifestyle risk factors for head and neck cancers (HNC), alcohol consumption and smoking have an undeniable role in the multifactorial aetiology of the disease. In recent years, the promotion of healthy lifestyle choices has gained significant attention as contributory to improving health and disease prevention. Interventions to tackle these risk factors are vitally important in disease prevention and progression. However, in order to effectively prevent the disease and reduce the risk factors, it is crucial to identify what upstream reasons lead to the adoption of these lifestyle risk factors in the first place. Stress being a constant aspect of modern-day life is known to contribute to alcohol and smoking practices. In this review paper, relevant literature was searched in PubMed database for stress, lifestyle factors, HNC and cancer to explore the role of stress and its associated biological pathways as an upstream factor in the adoption of lifestyle risk factors that cause HNC. It highlights the importance of stress pathways and the Hypothalamus Pituitary Adrenal (HPA) axis as a locus of interaction between stress, alcohol, smoking and cancer. Despite their widely accepted harmful effects, alcohol and smoking remain deeply rooted in contemporary life. A greater understanding of the impact of stress on lifestyle choices and an exploration of the mechanisms resulting in stress, alcohol- and smoking- related cancer may highlight opportunities for improved prevention measures through the modification of unhealthy lifestyle choices.

9.
Dent J (Basel) ; 10(7)2022 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-35877399

RESUMO

Suturing is an essential skill in dentistry and not one easily acquired. The COVID-19 pandemic prompted a change to the use of Thiel cadavers and online resources with the aim of improving skill acquisition using the best model available. This study investigated the utility of the Thiel cadaver for teaching suturing skills and the potential impact of the lockdown. Fifty-seven year 4 students attended a teaching session. Student views on this teaching were explored via a questionnaire survey and qualitative data collected from a focus group. Data were analysed using an inductive approach. The response rate was 53% (30 students) for the questionnaire with 9 students participating in the focus group. Independent feedback was provided by two members of the teaching staff. Online video resources were very well received by the students with 97% agreeing that it was useful preparation. Ninety percent (90%) thought that the cadaveric model was suitable for this teaching and realistic. Positive emergent themes from the focus group centred on the use of the cadaveric model and the positive and relaxed teaching and learning environment. Staff perceived this model as superior to previously used models. There were no reported negative pandemic impacts and the cadaver model was well received.

10.
J Geophys Res Space Phys ; 127(5): e2021JA029988, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35865125

RESUMO

Intense sunward (westward) plasma flows, named Subauroral Polarization Stream (SAPS), have been known to occur equatorward of the electron auroras for decades, yet their effect on the upper thermosphere has not been well understood. On the one hand, the large velocity of SAPS results in large momentum exchange upon each ion-neutral collision. On the other hand, the low plasma density associated with SAPS implies a low ion-neutral collision frequency. We investigate the SAPS effect during non-storm time by utilizing a Scanning Doppler Imager (SDI) for monitoring the upper thermosphere, SuperDARN radars for SAPS, all-sky imagers and DMSP Spectrographic Imager for the auroral oval, and GPS receivers for the total electron content. Our observations suggest that SAPS at times drives substantial (>50 m/s) westward winds at subauroral latitudes in the dusk-midnight sector, but not always. The occurrence of the westward winds varies with AE index, plasma content in the trough, and local time. The latitudinally averaged wind speed varies from 60 to 160 m/s, and is statistically 21% of the plasma. These westward winds also shift to lower latitude with increasing AE and increasing MLT. We do not observe SAPS driving poleward wind surges, neutral temperature enhancements, or acoustic-gravity waves, likely due to the somewhat weak forcing of SAPS during the non-storm time.

11.
J Forensic Sci ; 67(5): 1890-1898, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35819122

RESUMO

Cone-beam computed tomography (CBCT) enables the assessment of regressive morphological changes in teeth, which can be used to predict chronological age (CA) in adults. As each tooth region is known to have different correlations with CA, this study aimed to segment and quantify the sectional volumes of the tooth crown and root from CBCT scans to test their correlations with the chronological age (CA). Seventy-five CBCT scans from individuals with age between 20 and 60 years were collected retrospectively from an existing database. A total of 192 intact maxillary anterior teeth fulfilled the eligibility criteria. The upper tooth volume ratio (UTVR), lower tooth volume ratio (LTVR), and sex were used as predictor variables. The UTVR and LTVR parameters were both found to be differently correlated to CA and independent from each other. Regression models were derived from each tooth, with the highest R2 being the maxillary lateral incisor (R2  = 0.67). Additional single predictor models using each ratio were capable of reliably predicting the CA. The segmentation approach in volumetric adult dental age estimation proved to be beneficial in enhancing the reliability of the regression model.


Assuntos
Tomografia Computadorizada de Feixe Cônico , Coroa do Dente , Adulto , Tomografia Computadorizada de Feixe Cônico/métodos , Coroas , Humanos , Incisivo/diagnóstico por imagem , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Coroa do Dente/diagnóstico por imagem , Adulto Jovem
12.
Sci Total Environ ; 823: 153699, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35152004

RESUMO

Vehicle emission remote sensing devices have been widely used for monitoring and assessing the real-world emission performance of vehicles. They are also well-suited to identify candidate high emitting vehicles as remote sensing surveys measure the on-road, real-driving emissions (RDE) of a high proportion of the operational vehicle fleet passing through a testing site. This study uses the Gumbel distribution to characterize the fuel-specific NOx emission rates (g·kg-1) from diesel vans (formally referred to as light commercial vehicles or LCVs) and screen candidate high emitting vehicles. Van emission trends of four European countries (Belgium, Sweden, Switzerland and the UK) from Euro 3 to Euro 6a/b have been studied, and the impact of road grade on candidate Euro 6a/b high-emitters is also evaluated. The measurements of Euro 6a/b fleets from four countries are pooled together, and a consistent 4% of candidate high-emitters are found in both class II and class III Euro 6a/b vans, accounting for an estimated 24% and 21% total NOx emissions respectively. The pooled four country data is differentiated by vehicle models and manufacture groups. Engine downsizing of Euro 6a/b class II vans is suspected to worsen the emission performance when vehicles are driven under high engine load. The VW Group is found to be the manufacture with cleanest NOx emission performance in the Euro 6a/b fleets. By distinguishing high-emitters from normally behaving vehicles, a more robust description of fleet behaviour can be provided and high-emitting vehicles targeted for further testing by plume chasing or in an inspection garage. If the vehicle is found to have a faulty, deteriorated or tampered emission after-treatment system, the periodic vehicle inspection safety and environmental performance certificate could be revoked.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Veículos Automotores , Tecnologia de Sensoriamento Remoto , Emissões de Veículos/análise
13.
Dentomaxillofac Radiol ; 51(4): 20210335, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34995103

RESUMO

OBJECTIVES: This study aimed to investigate the reproducibility of dental age estimation methods in cone beam computed tomography (CBCT) and the correlation between dental (DA) and chronological (CA) ages. METHODS: The scientific literature was searched in six databases (PubMed, Scopus, LILACS, Web of Science, SciELO, and OATD). Only observational studies were selected. Within each study, the outcomes of interest were (I) the quantified reproducibility of the method (κ statistics and Intraclass correlation coefficient); and (II) the correlation (r) between the dental and chronological ages. A random-effect three-level meta-analysis was conducted alongside moderator analysis based on methods, arch (maxillary/mandibular), population, and number of roots. RESULTS: From 671 studies, 39 fulfilled the inclusion criteria, with one study reporting two different methods. The methods used in the studies were divided into metric (n = 17), volumetric (n = 20), staging (n = 2), and atlas (n = 1). All studies reported high examiner reproducibility. Group 1 (metric and volumetric) provided a high inverse weighted r ([Formula: see text] = -0.71, CI [-0.79,-0.61]), and Group 2 (staging) provided a medium-weighted r ([Formula: see text] = 0.49, CI [0.44, 0.53]). Moderator analysis on Group one did not show statistically significant differences between methods, tooth position, arch, and number of roots. An exception was detected in the analysis based on population (Southeast Asia, [Formula: see text] = -0.89, CI [-0.94,-0.81]). CONCLUSION: There is high evidence that CBCT methods are reproducible and reliable in dental age estimation. Quantitative metric and volumetric analysis demonstrated better performance in predicting chronological age than staging. Future studies exploring population-specific variability for age estimation with metric and volumetric CBCT analysis may prove beneficial.


Assuntos
Determinação da Idade pelos Dentes , Tomografia Computadorizada de Feixe Cônico Espiral , Dente , Determinação da Idade pelos Dentes/métodos , Tomografia Computadorizada de Feixe Cônico , Humanos , Reprodutibilidade dos Testes
14.
Br Dent J ; 231(11): 704-708, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34893735

RESUMO

Since the advice to 'stay at home' on 23 March 2020, there has been an enforced upsurge in the use of remote services. Clinical constraints within the dental schools have drastically reduced trainee/patient exposure and utilising available tools to increase patient contact is invaluable. Developing robust protocols and frameworks for remote activities is key to ensuring safe, secure and effective learning experiences. In Dundee, we have invested in careful planning to implement online engagement with clinical activity. A collaborative and iterative approach with NHS Tayside and other key stakeholders has resulted in a safe, online, clinical protocol that trainees, trainers and patients can have confidence in. The purpose of this article is to share our experience and to open a dialogue to work synergistically with other institutions to contribute towards a UK-wide remote training strategy.

15.
Front Cell Dev Biol ; 9: 714999, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34336866

RESUMO

The COVID-19 pandemic emerged as a largely unexplained outbreak of pneumonia cases, in Wuhan City, China and rapidly spread across the world. By 11th March 2020, WHO declared it as a global pandemic. The resulting restrictions, to contain its spread, demanded a momentous change in the lifestyle of the general population as well as cancer patients. This augmented negative effects on the mental health of patients with head and neck cancer (HNC), who already battle with the stress of cancer diagnosis and treatment. The causative agent of COVID-19, SARS-CoV2, gains entry through the Angiotensin converting enzyme 2 (ACE2) receptor, which is a component of the Renin Angiotensin System (RAS). RAS has been shown to influence cancer and stress such that it can have progressive and suppressive effects on both. This review provides an overview of SARS-CoV2, looks at how the RAS provides a mechanistic link between stress, cancer and COVID-19 and the probable activation of the RAS axis that increase stress (anxiogenic) and tumor progression (tumorigenic), when ACE2 is hijacked by SARS-CoV2. The mental health crises brought about by this pandemic have been highlighted in many studies. The emerging links between cancer and stress make it more important than ever before to assess the stress burden of cancer patients and expand the strategies for its management.

16.
Cancers (Basel) ; 13(2)2021 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-33418900

RESUMO

A single head and neck Cancer (HNC) is a globally growing challenge associated with significant morbidity and mortality. The diagnosis itself can affect the patients profoundly let alone the complex and disfiguring treatment. The highly important functions of structures of the head and neck such as mastication, speech, aesthetics, identity and social interactions make a cancer diagnosis in this region even more psychologically traumatic. The emotional distress engendered as a result of functional and social disruption is certain to negatively affect health-related quality of life (HRQoL). The key biological responses to stressful events are moderated through the combined action of two systems, the hypothalamus-pituitary-adrenal axis (HPA) which releases glucocorticoids and the sympathetic nervous system (SNS) which releases catecholamines. In acute stress, these hormones help the body to regain homeostasis; however, in chronic stress their increased levels and activation of their receptors may aid in the progression of cancer. Despite ample evidence on the existence of stress in patients diagnosed with HNC, studies looking at the effect of stress on the progression of disease are scarce, compared to other cancers. This review summarises the challenges associated with HNC that make it stressful and describes how stress signalling aids in the progression of cancer. Growing evidence on the relationship between stress and HNC makes it paramount to focus future research towards a better understanding of stress and its effect on head and neck cancer.

17.
Eur J Dent Educ ; 25(4): 670-678, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33315279

RESUMO

INTRODUCTION: Patient safety within dental education is paramount. Wrong-site surgery (WSS) tooth extraction is not uncommon and is a significant never event (NE) in dentistry. This study aimed to explore dental schools' undergraduate experience of NEs, safety interventions implemented and the impact on student experience. METHODS: All 16 UK dental schools were surveyed via email. RESULTS: The response rate was 100%. A modified World Health Organization (WHO) checklist was used within institutions (94%) including pre-operative briefings and recording teeth on whiteboards (81%, respectively). Students were directly supervised performing extractions (63%) utilising a 1:4 staff: student ratio. WSS by students was reported in 69% of schools, with student experience being impacted by an increased patient safety focus. DISCUSSION: This study demonstrated an increased utilisation of an adapted WHO checklist. Modification of practices to ensure patient safety was demonstrated at all schools, irrespective of student WSS occurrences. Institutions experiencing student NEs commonly implemented WHO checklists and recording teeth for extraction on whiteboards. Other strategies included direct staff supervision and pre-operative briefings. CONCLUSION: UK dental schools have increased the emphasis on patient safety by the implementation of national healthcare models, for example WHO checklists and pre-operative briefings. These strategies both aim to improve communication and teamwork. Increased levels of staff supervision foster greater quality of teaching; however, this has resulted in reduced student clinical experience. A proposed minimum standard for undergraduate surgery is suggested to ensure safe and competent dental practitioners of the future.


Assuntos
Odontólogos , Faculdades de Odontologia , Currículo , Educação em Odontologia , Humanos , Erros Médicos/prevenção & controle , Papel Profissional , Estudantes , Inquéritos e Questionários , Ensino , Reino Unido
18.
Sci Total Environ ; 750: 142088, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33182199

RESUMO

The quantification and comparison of NOX emission from in-situ car fleets, and identification of the highest emitters is an ongoing challenge. This challenge will become more important as new and increasingly complex emissions removal systems penetrate the market. We combine real-world data with new-to-the-field statistical methods to describe fleet-scale emissions behaviours and identify candidate gross-emitter vehicles. 19,605 passenger cars were observed using a Remote Sensing Device across Aberdeen in 2015. Of these, 736 were Euro 6 Passenger Cars. The distribution of observed pollutant per unit of fuel burnt ratios for most fuel type and Euro standards followed an asymmetrical shape best characterised by the Gumbel distribution. The Gumbel distribution approach was not able to fully replicate the distribution of measurements of petrol or Euro 6 diesel cars due to the presence of a subset of high-emitting outliers, ranging from the 13th percentile for Euro 3 petrol to the 2nd percentile for Euro 6 petrol, with Euro 6 diesel having a 5th percentile outlier value. No outlier fraction was observed for pre-Euro 6 diesels. The off-model fractions resembled Gumbel distributed data and in some cases could be modelled as a separate distribution with the fleet behaving as a superposition of them. It is shown that VSP was not directly linked to this behaviour and it is hypothesised that it is caused by the emissions control systems operating sub-optimally. The reasons for sub-optimal operation are beyond the scope of this paper but may be linked to air-fuel mixture sensors, cold-start running and deterioration of the catalytic converter. Larger data-sets with more Euro 6 passenger cars are required to fully test this. Application of this methodology to larger data sets from more widely deployed remote sensing devices will allow observers to identify potentially problematic vehicles for further investigation into their emission control systems.

19.
Sci Total Environ ; 763: 142974, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33121764

RESUMO

Refrigerated vans used for home deliveries are attracting attention as online grocery shopping in the UK is expanding rapidly and contributes to the increasing greenhouse gas (CO2) and nitrogen oxides (NOX) emissions. These vans are typically 3.5-tonne gross weight vehicles equipped with temperature-controlled units called Transport Refrigeration Units (TRUs), which are usually powered off the vehicles' engine. It is obvious that vehicles with added weight of TRUs consume more fuel and emit more NOX, let alone the vehicles' diesel engines are also powering the refrigeration units, which further elevates the emissions. This research uses an instantaneous vehicle emission model PHEM (version 13.0.3.21) to simulate the real-world emissions from refrigerated vans. A validation of PHEM is included using data from laboratory (chassis dynamometer) tests over a realistic driving profile (the London Drive Cycle), to assess its ability to quantify the impact of changing vehicle weights and carrying loads. The impact of the TRU weight, greater frontal area increasing aerodynamic drag and refrigeration load on van emissions is then estimated by PHEM. The influence of ambient temperature, cargo weight and driving condition on CO2 and NOX emission from refrigerated van are also assessed. Overall CO2 emissions of vans with TRUs are found to be 15% higher than standard vehicles, with NOX emissions estimated to be elevated by 18%. This confirms the need to take into account the impact of additional engine load when predicting van emissions in this and other sectors such as ambulances which are relatively heavy, high powered vehicles. Moreover, findings of the impact of TRUs on fuel consumptions can be used to optimize fuel-saving strategies for refrigerated vans and test cases for alternative low- or zero-emission technologies, to support progress to a sustainable net-zero society.

20.
Evid Based Dent ; 21(3): 82-83, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32978531

RESUMO

Basic health and infection control measures are the main methods of protection against COVID-19. Patients are well informed about how practitioners should be conducting themselves, however, they may lose trust in clinicians who fail to demonstrate, and promote those same basic prevention measures. The broader COVID-19 strategy has included the rapid development and deployment of swabs and antibody tests. Flaws in testing fail to offer assurances due to false negatives while even true positives cannot guarantee future immunity as there is uncertainty regarding long-term antibody response. An understanding of human factors and an appreciation of the limitations of available tests could offer healthcare staff mechanisms to encourage safety.


Assuntos
Betacoronavirus , Técnicas de Laboratório Clínico , Infecções por Coronavirus , Pandemias , Pneumonia Viral/epidemiologia , Formação de Anticorpos , COVID-19 , Teste para COVID-19 , Infecções por Coronavirus/diagnóstico , Humanos , SARS-CoV-2
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