Additive Manufacturing of Continuous Fiber-Reinforced Polymer Composites via Fused Deposition Modelling: A Comprehensive Review.

Additive manufacturing (AM) has arisen as a transformative technology for manufacturing complex geometries with enhanced mechanical properties, particularly in the realm of continuous fiber-reinforced polymer composites (CFRPCs). Among various AM techniques, fused deposition modeling (FDM) stands out as a promising method for the fabrication of CFRPCs due to its versatility, ease of use, flexibility, and cost-effectiveness. Several research papers on the AM of CFRPs via FDM were summarized and therefore this review paper provides a critical examination of the process-printing parameters influencing the AM process, with a focus on their impact on mechanical properties. This review covers details of factors such as fiber orientation, layer thickness, nozzle diameter, fiber volume fraction, printing temperature, and infill design, extracted from the existing literature. Through a visual representation of the process parameters (printing and material) and properties (mechanical, physical, and thermal), this paper aims to separate out the optimal processing parameters that have been inferred from various research studies. Furthermore, this analysis critically evaluates the current state-of-the-art research, highlighting advancements, applications, filament production methods, challenges, and opportunities for further development in this field. In comparison to short fibers, continuous fiber filaments can render better strength; however, delamination issues persist. Various parameters affect the printing process differently, resulting in several limitations that need to be addressed. Signifying the relationship between printing parameters and mechanical properties is vital for optimizing CFRPC fabrication via FDM, enabling the realization of lightweight, high-strength components for various industrial applications.

Effectiveness, perceptions and environmental benefits of remote consultation for adults referred with recurrent tonsillitis.

INTRODUCTION: We evaluate remote consultation for adult patients referred with recurrent sore throat, measuring the effectiveness of the consultation, satisfaction and environmental impact. METHODS: Eligible patients were invited to telephone clinics, undertaking a satisfaction survey after consultation, focusing on perceived convenience, satisfaction, cost and travel arrangements (used to calculate potential environmental benefit). Provider opinion was also captured. RESULTS: Forty-eight of 60 patients attended, with 38 (63%) eligible for inclusion. Thirty-six of these 38 patients (95%) had a definitive outcome of tonsillectomy (27/38) or discharge (9/38). Thirty-three of the 38 patients (87%) responded to the survey and reported high satisfaction in all arms of questioning (mean Likert ranking = 4.7/5). A mean of 3.76 hours of missed work and 5.17kg carbon dioxide emission equivalents were saved per patient. Provider responses were positive towards ongoing remote consultation use. CONCLUSIONS: Telephone consultation for adult patients considered for tonsillectomy is convenient to patients in terms of cost and time, reduces environmental harm and is associated with high patient and provider satisfaction.

Outcomes of remote versus face-to-face ear, nose and throat outpatient consultation on patient pathways.

INTRODUCTION: Remote consultation has potential benefits in increasing patient pathway efficiency and has been found to reduce costs and carbon emissions. Previous studies of remote consultation in ear, nose and throat (ENT) practice have reported mixed results and used relatively small sample sizes. The aim of this article is to study the impact of remote telephone consultation on ENT clinic outcomes and pathway efficiency, compared with in-person review, within new and follow-up patient cohorts and subspeciality, where previous studies demonstrate mixed and inconclusive results. METHODS: This was a comparison of remote clinic appointment outcomes over a 2-month period from a single ENT referral centre (426) with an equivalent data set of face-to-face clinic appointments over a similar time frame (1,533). Statistical analysis included chi-squared test for clinic outcomes and two-sample t-squared test for mean hand-off between both cohorts (p < 0.05). RESULTS: For new referrals, remote consultation was associated with statistically significantly greater rates of follow-up (p < 0.00001), investigation (p = 0.00251) and hand-off (p < 0.00013) than patients seen face-to-face - particularly where presenting with head and neck symptoms. For follow-up patients, remote consultation had similar rates of investigation (p = 0.11071) or further follow-up (p = 0.08) and mean hand-off (p < 0.11764) to those seen face-to-face. CONCLUSIONS: Remote consultation in ENT could become the norm for follow-up patients, but should be used with caution in the initial consultation of new patients.

Disparities in access to ear and hearing care in Cambodia: a mixed methods study on patient experiences.

OBJECTIVE: Chronic suppurative otitis media is a major global disease disproportionately affecting low- and middle-income countries, but few studies have explored access to care for those with ear and hearing disorders. METHOD: In a tertiary hospital in Cambodia providing specialist ear services, a mixed method study was undertaken. This study had three arms: (1) quantitative analysis of patients undergoing ear surgery, (2) a questionnaire survey and (3) semi-structured in-depth interviews. RESULTS: Patients presented with advanced middle-ear disease and associated hearing loss at rates that are amongst the highest per capita levels globally. Patients reported several structural, financial and socio-cultural barriers to treatment. This study showed a significant burden of ear disease in Cambodia, which reflects a delay in receiving timely and effective treatment. CONCLUSION: This study highlights the opportunity to integrate effective ear and hearing care into primary care service provision, strengthening the package of activities delivered at government facilities.

Artificial neural network models: implementation of functional near-infrared spectroscopy-based spontaneous lie detection in an interactive scenario.

Deception is an inevitable occurrence in daily life. Various methods have been used to understand the mechanisms underlying brain deception. Moreover, numerous efforts have been undertaken to detect deception and truth-telling. Functional near-infrared spectroscopy (fNIRS) has great potential for neurological applications compared with other state-of-the-art methods. Therefore, an fNIRS-based spontaneous lie detection model was used in the present study. We interviewed 10 healthy subjects to identify deception using the fNIRS system. A card game frequently referred to as a bluff or cheat was introduced. This game was selected because its rules are ideal for testing our hypotheses. The optical probe of the fNIRS was placed on the subject's forehead, and we acquired optical density signals, which were then converted into oxy-hemoglobin and deoxy-hemoglobin signals using the Modified Beer-Lambert law. The oxy-hemoglobin signal was preprocessed to eliminate noise. In this study, we proposed three artificial neural networks inspired by deep learning models, including AlexNet, ResNet, and GoogleNet, to classify deception and truth-telling. The proposed models achieved accuracies of 88.5%, 88.0%, and 90.0%, respectively. These proposed models were compared with other classification models, including k-nearest neighbor, linear support vector machines (SVM), quadratic SVM, cubic SVM, simple decision trees, and complex decision trees. These comparisons showed that the proposed models performed better than the other state-of-the-art methods.

Access to ear and hearing care services in Cambodia: a qualitative enquiry into experiences of key informants.

OBJECTIVE: In Cambodia, little is known about the state of ear and hearing care, or the roles providers or key stakeholders play in delivering services. METHOD: This was an exploratory study using semi-structured qualitative interviews and a questionnaire addressed to key stakeholders to explore their perceptions and experiences in providing services to people suffering from ear disease or hearing loss in Cambodia. RESULTS: Several challenges were described including a lack of hearing services to meet the demand, especially outside Phnom Penh in primary care and aural rehabilitation. Supply-side challenges include a shortage of trained professionals, facilities and resources, poor co-ordination between providers, unclear referral pathways, and long wait times. CONCLUSION: Now is an opportune time to build on the positive trend in providing integrated care for non-communicable diseases in Cambodia, through the integration of effective ear and hearing care into primary care and strengthening the package of activities delivered at government facilities.

Effectiveness of an online module: climate-change and sustainability in clinical practice.

BACKGROUND: Climate change has significant implications for health, yet healthcare provision itself contributes significant greenhouse gas emission. Medical students need to be prepared to address impacts of the changing environment and fulfil a key role in climate mitigation. Here we evaluate the effectiveness of an online module on climate-change and sustainability in clinical practice designed to achieve learning objectives adapted from previously established sustainable healthcare priority learning outcomes. METHODS: A multi-media, online module was developed, and 3rd and 4th year medical students at Brighton and Sussex Medical School were invited to enrol. Students completed pre- and post-module questionnaires consisting of Likert scale and white space answer questions. Quantitative and qualitative analysis of responses was performed. RESULTS: Forty students enrolled and 33 students completed the module (83% completion rate). There was a significant increase in reported understanding of key concepts related to climate change and sustainability in clinical practice (p < 0.001), with proportion of students indicating good or excellent understanding increasing from between 2 - 21% students to between 91 - 97% students. The majority (97%) of students completed the module within 90 min. All students reported the module was relevant to their training. Thematic analysis of white space responses found students commonly reported they wanted access to more resources related to health and healthcare sustainability, as well as further guidance on how to make practical steps towards reducing the environmental impact within a clinical setting. CONCLUSION: This is the first study to evaluate learner outcomes of an online module in the field of sustainable health and healthcare. Our results suggest that completion of the module was associated with significant improvement in self-assessed knowledge of key concepts in climate health and sustainability. We hope this approach is followed elsewhere to prepare healthcare staff for impacts of climate change and to support improving the environmental sustainability of healthcare delivery. TRIAL REGISTRATION: Study registered with Brighton and Sussex Medical School Research Governance and Ethics Committee (BSMS RGEC). Reference: ER/BSMS3576/8, Date: 4/3/2020.

Loop-Box: Multiagent Direct SLAM Triggered by Single Loop Closure for Large-Scale Mapping.

In this article, we present a multiagent framework for real-time large-scale 3-D reconstruction applications. In SLAM, researchers usually build and update a 3-D map after applying nonlinear pose graph optimization techniques. Moreover, many multiagent systems are prevalently using odometry information from additional sensors. These methods generally involve extensive computer vision algorithms and are tightly coupled with various sensors. We develop a generic method for the key challenging scenarios in multiagent 3-D mapping based on different camera systems. The proposed framework performs actively in terms of localizing each agent after the first loop closure between them. It is shown that the proposed system only uses monocular cameras to yield real-time multiagent large-scale localization and 3-D global mapping. Based on the initial matching, our system can calculate the optimal scale difference between multiple 3-D maps and then estimate an accurate relative pose transformation for large-scale global mapping.

A survey of UK and Irish surgeons' attitudes, behaviours and barriers to change for environmental sustainability.

INTRODUCTION: Surgery is a major contributor to the large environmental impact of healthcare, demanding urgent attention. To date there are no data on the attitudes and behaviours of surgeons towards climate change, or perceived barriers towards sustainable practice. METHODS: We invited surgeons and surgical trainees in the UK and Ireland to participate in an online survey (developed in accordance with the CHERRIES checklist) conducted between June and November 2020 and disseminated via the Royal College of Surgeons of England, Edinburgh and Ireland, the Association of Surgeons in Training and through local communication. RESULTS: We received 130 responses, across 14 surgical specialties. The majority of respondents (122/130; 94%) were concerned about the threat of climate change. Most respondents had instigated more sustainable practices in their personal lives (113/130; 87%) and, to a lesser extent, at work (73/130; 56%). Surgeons were willing to make changes to their clinical practice (107/130; 82%), but the main perceived barrier to improving sustainability was a lack of leadership (92/130; 70%). Surgeons welcomed greater leadership and guidance from national bodies (118/130; 91%) and more monitoring and regulation (113/130; 87%). CONCLUSIONS: The surgeons who responded to our survey are concerned about climate change and willing to engage in efforts to transition to more sustainable practice, but would welcome greater support, guidance and leadership.

Effect of stimulation duration to the existence of initial dip.

In this paper, we investigate the effect of stimulation durations on the hemodynamic responses (HRs) in the somatosensory cortex. In doing so, the relationship between stimulation duration and the initial dip is also investigated. The HRs are measured using functional near-infrared spectroscopy (fNIRS). The HR signals related to finger poking are acquired from the left somatosensory cortex. Two different stimulation durations (i.e., 1 and 5 sec) were tested in this study. From the results of the study, it is concluded that the stimulation duration of 1 sec (short stimulus) evokes initial dip in the somatosensory cortex, but it disappears as the stimulation duration gets longer. Therefore, the 1-sec stimulation duration can serve the purpose of the fNIRS-based brain-computer interface.

Surgical treatment of chronic ear disease in remote or resource-constrained environments.

BACKGROUND: Surgery for chronic suppurative otitis media performed in low- and middle-income countries creates specific challenges. This paper describes the equipment and a variety of techniques that we find best suited to these conditions. These have been used over many years in remote areas of Nepal. RESULTS AND CONCLUSION: Extensive chronic suppurative otitis media is frequently encountered, with limited pre-operative investigation or treatment possible. Techniques learnt in better-resourced settings with good follow up need to be modified. The paper describes surgical methods suitable for resource-poor conditions, with rationales. These include methods of tympanoplasty for subtotal wet perforations, hearing reconstruction in wet ears and open cavities, large aural polyps, and canal wall down mastoidectomy with cavity obliteration. Various types of autologous ossiculoplasty are described in detail for use in the absence of prostheses. The following topics are discussed: decision-making for surgery on wet or best hearing ears, children, bilateral surgery, working with local anaesthesia, and obtaining adequate consent in this environment.

Models of service delivery for ear and hearing care in remote or resource-constrained environments.

BACKGROUND: There is poor availability of ear and hearing services globally, because of a lack of infrastructure, funding, equipment and appropriately trained personnel. When deciding upon delivery of ear and hearing services, an approach based upon community assessment is advocated, with subsequent asset mapping and acquisition. OBJECTIVES: Some of the challenges to delivery of care in resource-constrained or remote environments are acknowledged, with discussion of several existing models of service delivery, and their advantages and disadvantages. Public health and telehealth are also mentioned. This article may assist those trying to set up new programmes in ear and hearing health.

Adaptive filtering of physiological noises in fNIRS data.

The study presents a recursive least-squares estimation method with an exponential forgetting factor for noise removal in functional near-infrared spectroscopy data and extraction of hemodynamic responses (HRs) from the measured data. The HR is modeled as a linear regression form in which the expected HR, the first and second derivatives of the expected HR, a short-separation measurement data, three physiological noises, and the baseline drift are included as components in the regression vector. The proposed method is applied to left-motor-cortex experiments on the right thumb and little finger movements in five healthy male participants. The algorithm is evaluated with respect to its performance improvement in terms of contrast-to-noise ratio in comparison with Kalman filter, low-pass filtering, and independent component method. The experimental results show that the proposed model achieves reductions of 77% and 99% in terms of the number of channels exhibiting higher contrast-to-noise ratios in oxy-hemoglobin and deoxy-hemoglobin, respectively. The approach is robust in obtaining consistent HR data. The proposed method is applied for both offline and online noise removal.

Implementation and results of a surgical training programme for chronic suppurative otitis media in Cambodia.

BACKGROUND: Chronic suppurative otitis media is a massive public health problem in numerous low- and middle-income countries. Unfortunately, few low- and middle-income countries can offer surgical therapy. METHODS: A six-month long programme in Cambodia focused on training local surgeons in type I tympanoplasty was instigated. Qualitative educational and quantitative surgical outcomes were evaluated in the 12 months following programme completion. A four-month long training programme in mastoidectomy and homograft ossiculoplasty was subsequently implemented, and the preliminary surgical and educational outcomes were reported. RESULTS: A total of 124 patients underwent tympanoplasty by the locally trained surgeons. Tympanic membrane closure at six weeks post-operation was 88.5 per cent. Pure tone audiometry at three months showed that 80.9 per cent of patients had improved hearing, with a mean gain of 17.1 dB. The trained surgeons reported high confidence in performing tympanoplasty. Early outcomes suggest the local surgeons can perform mastoidectomy and ossiculoplasty as safely as overseas-trained surgeons, with reported surgeon confidence reflecting these positive outcomes. CONCLUSION: The training programme has demonstrated success, as measured by surgeon confidence and operative outcomes. This approach can be emulated in other settings to help combat the global burden of chronic suppurative otitis media.

A cross-sectional evaluation of the validity of a smartphone otoscopy device in screening for ear disease in Nepal.

OBJECTIVES: Hearing loss is a neglected international health problem. The greatest burden of ear disease is in low-income countries where there is also a lack of resources. In this context, screening for otological disease may be worthwhile. Cupris© has developed an otoscopy device that offers the possibility of low-cost mass screening in remote communities. We evaluated the validity of this device in diagnosing ear disease and in determining whether referral to an ENT centre is warranted. DESIGN: Cross-sectional study. SETTING: Outpatient clinic, Nepal. PARTICIPANTS: All adults and children were invited to take part over a 2-day period. The Cupris© device was used to record participants otological history and examination. Stored history and images were assessed in the United Kingdom by a Consultant-grade ENT Surgeon, who provided a diagnosis and decided whether referral to an ENT centre was warranted. After screening with the Cupris© device, participants were immediately assessed by a UK trained ENT Consultant Surgeon using a standard otoscope ("standard assessment"). A diagnosis was recorded for each participant and a decision was made as to whether referral to an ENT centre was warranted. OUTCOMES: Concordance in primary diagnosis (analysed per ear) and concordance in the decision to refer (analysed per patient). Cohen's kappa coefficient for inter-rater agreement in diagnosis. RESULTS: Fifty-six patients agreed to participate. In four patients, the quality of video recorded precluded a diagnosis or management plan. These patients were excluded from subsequent analysis, leaving 52 patients for analysis. The same diagnosis was reached for 99 of 104 ears when comparing the Cupris© device to standard assessment (95% concordance), with Cohen's kappa coefficient of 0.89. The decision as to whether a patient should be referred to an ENT centre for further assessment was the same for all 52 participants when comparing the Cupris© device to standard assessment. CONCLUSIONS: When compared to standard assessment, the Cupris© device is a valid tool for the diagnosis of ear disease and decision for onward referral. It shows considerable promise for use by trained non-medical workers, as a low-cost and portable tool to screen for ear disease in remote settings, particularly in low- and middle-income countries.

The genetics of cholesteatoma. A systematic review using narrative synthesis.

OBJECTIVE: A cholesteatoma is a mass of keratinising epithelium in the middle ear. It is a rare disorder that is associated with significant morbidity, and its causative risk factors are poorly understood; on a global scale, up to a million people are affected by this each year. We have conducted a systematic literature review to identify reports about the heritability of cholesteatoma or any constitutional genetic factors that may be associated with its aetiology. DATA SOURCES: A systematic search of MEDLINE (EBSCO) and two databases of curated genetic research (OMIM and Phenopedia) was conducted. STUDY SELECTION: The participants and populations of interest for this review were people treated for cholesteatoma and their family members. The studies of interest reported evidence of heritability for the trait, or any association with congenital syndromes and particular genetic variants. DATA EXTRACTION: The searches identified 449 unique studies, of which 35 were included in the final narrative synthesis. DATA SYNTHESIS: A narrative synthesis was conducted, and data were tabulated to record characteristics, including study design, genetic data and author conclusions. Most of the studies identified in the literature search, and described here, are case reports and so represent the lowest level of evidence. In a few case reports, congenital and acquired cholesteatomas have been shown to segregate within families in the pattern typical of a monogenic or oligogenic disorder with incomplete penetrance. Evidence from syndromic cases could suggest that genes controlling ear morphology may be risk factors for cholesteatoma formation. CONCLUSIONS: This is the first systematic review about the genetics of cholesteatoma, and we have identified a small body of relevant literature that provides evidence of a heritable component for its aetiology. Cholesteatoma is a complex and heterogeneous clinical phenotype, and it is often associated with chronic otitis media and with some rare congenital syndromes known to affect ear morphology and related pathologies.