274 research outputs found

    Understanding local neuromuscular mechanisms that explain the efficacy of interventions for patellofemoral pain

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    Patellofemoral pain (PFP) is a common and persistent knee pain complaint among all age ranges, especially highly active people. Multiple approaches have been used to understand symptom persistence, including identifying a mechanism explaining intervention benefits (i.e. changes in specific deficits in groups that show symptoms’ improvement). Research has been conducted to identify the characteristics associated with PFP, but uncertainty regarding local neuromuscular characteristics remain evident. The thesis aimed to a) identify the local neuromuscular characteristics associated with PFP, b) develop an evidence informed laboratory protocol to detect those characteristics, c) establish protocol reliability and feasibility, and d) identify interventions that can target these neuromuscular characteristics. A systematic review with meta-analysis was completed to identify the neuromuscular characteristics of all muscles that cross the knee in people with PFP compared to uninjured groups. Ten deficits within three neuromuscular domains were found. Within the electromyography (EMG) domain, a delay in Vastus medialis (VM) relative to Vastus lateralis (VL) excitation onset, a high Biceps femoris (BF) mean excitation amplitude, and a lower Hoffman-reflex amplitude of VM were identified. Within the muscle performance domain, lower isometric, concentric, and eccentric extensors peak torque and total work, lower concentric flexors peak torque, and lower rate of torque development (RTD) to reach 30%, 60% and 90% of extensors peak torque were identified. Hamstring tightness was identified within muscle flexibility domain. The systematic review was published and the results used to inform testing protocol development. A second systematic review with meta-analysis was conducted to identify interventions that can target the local deficits associated with PFP. The results indicate that currently an intervention that effectively modifies EMG characteristics cannot be identified. Predominantly, exercise interventions have effects on strength and flexibility in PFP. Specifically, hip and knee targeted exercises are found to have a potential mechanism of benefit through both characteristics categories. A unique approach was introduced within the thesis to develop a deficit-detection protocol based on systematic review results. This approach provided a comprehensive analysis of the protocols from the studies that were included in the meta-analysis. A battery of tests was developed and included; a) VM-VL excitation onset timing in step-up task, b) BF mean excitation amplitude in single-leg triple-hop test, c) isometric, d) concentric and e) eccentric extensors peak torque, f) RTD to 30%, 60% and 90% of isometric peak torque, and hamstrings flexibility. Reliability testing of the deficit-detection protocol was conducted with both uninjured and participants with PFP over two phases. Phase one evaluated the original protocols adapted from the review. Phase two was performed on the EMG and RTD domains to explore the effects of signal processing parameters on reliability, such as; onset detection thresholds modification, unnormalised signals, and the addition of absolute RTD. For the PFP group: reliable results were demonstrated for concentric and eccentric extensors peak torque; RTD of the quadriceps at 25ms, 50ms and 90% of peak torque; and hamstrings flexibility. The uninjured group showed reliable results in: unnormalised BF mean excitation amplitude; all three peak torque tests; RTD to 30% of peak torque and at 150 and 175 milliseconds; and hamstrings flexibility. To establish participant recruitment rate and retention, in addition to the acceptability of the test protocol, a preliminary feasibility study of the deficit-detection protocol was conducted. A sample of 14 participants with PFP were recruited and tested at the Mile-end campus of QMUL before and after a six weeks period. Feasibility results indicate that 25.5% were willing to participate following an online screening process (n=17/55) and 82% met the eligibility criteria following face-to-face assessment (n=14/17). Recruitment rate was 0.5 participants per week and drop-out rate was 35.2% (n=11/17). The results indicate that the protocol did not meet all a-priori feasibility criteria, but the results can inform future research planning. The thesis has successfully identified local deficits associated with PFP, developed a test protocol that demonstrates reliability in evaluating these deficits and assessed the feasibility of the protocol in individuals with PFP. Interventions to cause change within these local deficits have been identified, with gap maps demonstrating where further research is required to better align the mechanisms of treatment effects with specific deficits associated with PFP

    Aspects of the preparation and properties of some conformationally biased dihydroaromatic compounds

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    The work described in this thesis is concerned with preparation and conformation of dihydroaromatic molecules. In part I the use of alkaline metal/liquid ammonia solutions in the preparation of dihydroaromatic compounds is reviewed; particular emphasis being placed on the effect of the substituent on the nature of the products obtained. The reduction of several benzoic acid and naphthoic acid derivatives has been investigated with a view to using the alkaline metal/liquid ammonia sequence to prepare sterically hindered dihydrobenzoic acids and dihydronaphthoic acids. 1,4-Dihydro-8-methyl -l-naphthoic acid and 1,4-dihydro-8-isopropyl-l-naphthoic acid have been successfully prepared by this method. In the course of this work the reduction of the lactones phthalide and naphthalide and their dimethyl analogues have been studied. In these cases, there is competition between reduction of the aromatic ring and of the ester formation. Factors which influence the competition between these two reaction pathways have been investigated. In Part II evidence for the conformations of dihydro-aromatic rings is reviewed and the effect of the substituents is discussed. Nuclear magnetic resonance (nmr) spectroscopic data for dihydroaromatic compounds prepared in Part I are analysed in detail; these data are then used to determine the conformations of these conformationally biased and conformationally locked dihydroaromatic rings

    Optimising surface roughness and density in titanium fabrication via laser powder bed fusion

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    The Ti6Al4V alloy has many advantages, such as being lightweight, formal, and resistant to corrosion. This makes it highly desirable for various applications, especially in the aerospace industry. Laser Powder Bed Fusion (LPBF) is a technique that allows for the production of detailed and unique parts with great flexibility in design. However, there are challenges when it comes to achieving high-quality surfaces and porosity formation in the material, which limits the wider use of LPBF. To tackle these challenges, this study uses statistical techniques called Design of Experiments (DoE) and Analysis of Variance (ANOVA) to investigate and optimise the process parameters of LPBF for making Ti6Al4V components with improved density and surface finish. The parameters examined in this study are laser power, laser scan speed, and hatch space. The optimisation study results show that using specific laser settings, like a laser power of 175 W, a laser scan speed of 1914 mm/s, and a hatch space of 53 µm, produces Ti6Al4V parts with a high relative density of 99.54% and low top and side surface roughness of 2.6 µm and 4.3 µm, respectively. This promising outcome demonstrates the practicality of optimising Ti6Al4V and other metal materials for a wide range of applications, thereby overcoming existing limitations and further expanding the potential of LPBF while minimising inherent process issues

    Cost-Effectiveness of Propofol (Diprivan) Versus Inhalational Anesthetics to Maintain General Anesthesia in Noncardiac Surgery in the United States.

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    Abstract Objectives It is not known whether using propofol total intravenous anaesthesia (TIVA) to reduce incidence of postoperative nausea and vomiting (PONV) is cost-effective. We assessed the economic impact of propofol TIVA versus inhalational anesthesia in adult patients for ambulatory and inpatient procedures relevant to the US healthcare system. Methods Two models simulate individual patient pathways through inpatient and ambulatory surgery with propofol TIVA or inhalational anesthesia with economic inputs from studies on adult surgical US patients. Efficacy inputs were obtained from a meta-analysis of randomized controlled trials. Probabilistic and deterministic sensitivity analyses assessed the robustness of the model estimates. Results Lower PONV rate, shorter stay in the post-anesthesia care unit, and reduced need for rescue antiemetics offset the higher costs for anesthetics, analgesics, and muscle relaxants with propofol TIVA and reduced cost by 11.41 ± 10.73 USD per patient in the inpatient model and 11.25 ± 9.81 USD in the ambulatory patient model. Sensitivity analyses demonstrated strong robustness of the results. Conclusions Maintenance of general anesthesia with propofol was cost-saving compared to inhalational anesthesia in both inpatient and ambulatory surgical settings in the United States. These economic results support current guideline recommendations, which endorse propofol TIVA to reduce PONV risk and enhance postoperative recovery

    Hybrid finite element–smoothed particle hydrodynamics modelling for optimizing cutting parameters in CFRP composites

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    Carbon-fibre-reinforced plastic (CFRP) is increasingly being used in various applications including aerospace, automotive, wind energy, sports, and robotics, which makes the precision modelling of its machining operations a critical research area. However, the classic finite element modelling (FEM) approach has limitations in capturing the complexity of machining, particularly with regard to the interaction between the fibre–matrix interface and the cutting edge. To overcome this limitation, a hybrid approach that integrates smoothed particle hydrodynamics (SPHs) with FEM was developed and tested in this study. The hybrid FEM-SPH approach was compared with the classic FEM approach and validated with experimental measurements that took into account the cutting tool’s round edge. The results showed that the hybrid FEM-SPH approach outperformed the classic FEM approach in predicting the thrust force and bounce back of CFRP machining due to the integrated cohesive model and the element conversion after failure in the developed approach. The accurate representation of the fibre–matrix interface in the FEM-SPH approach resulted in predicting precise chip formation in terms of direction and morphology. Nonetheless, the computing time of the FEM-SPH approach is higher than the classic FEM. The developed hybrid FEM-SPH model is promising for improving the accuracy of simulation in machining processes, combining the benefits of both techniques

    Chip formation and orthogonal cutting optimisation of unidirectional carbon fibre composites

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    This study presents a thorough experimental investigation utilising the design of experiments and analysis of variance (ANOVA) to examine the impact of machining process parameters on chip formation mechanisms, machining forces, workpiece surface integrity, and damage resulting from the orthogonal cutting of unidirectional CFRP. The study identified the mechanisms behind chip formation and found it to significantly impact the workpiece orientation of fibre and the tool’s cutting angle, resulting in increased fibre bounceback at larger fibre orientation angles and when using smaller rake angle tools. Increasing the depth of cut and fibre orientation angle results in an increased damage depth, while using higher rake angles reduces it. An analytical model based on response surface analysis for predicting machining forces, damage, surface roughness, and bounceback was also developed. The ANOVA results indicate that fibre orientation is the most significant factor in machining CFRP, while cutting speed is insignificant. Increasing fibre orientation angle and depth leads to deeper damage, while larger tool rake angles re-duce damage. Machining workpieces with 0° fibre orientation angle results in the least subsurface damage, and surface roughness is unaffected by the tool rake angle for fibre orientations between 0° to 90° but worsens for angles greater than 90°. Optimisation of cutting parameters were subsequently optimised to improve machined workpiece surface quality and reduce forces. The experimental results showed that negative rake angle and cutting at moderately low speeds (366 mm/min) is the optimal conditions for machining laminates with a fibre angle of θ = 45°. On the other hand, for composite materials with fibre angles of θ = 90° and θ = 135°, it is recommended to use a high positive rake angle and cutting speeds

    LKAU23 at Qur’an QA 2023: Using Transformer Models for Retrieving Passages and Finding Answers to Questions from the Qur’an

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    The Qur’an QA 2023 shared task has two sub tasks: Passage Retrieval (PR) task and Machine Reading Comprehension (MRC) task. Our participation in the PR task was to further train several Arabic pre-trained models using a Sentence-Transformers architecture and to ensemble the best performing models. The results of the test set did not reflect the results of the development set. CL-AraBERT achieved the best results, with a 0.124 MAP. We also participate in the MRC task by further fine-tuning the base and large variants of AraBERT using Classical Arabic and Modern Standard Arabic datasets. Base AraBERT achieved the best result with the development set with a partial average precision (pAP) of 0.49, while it achieved 0.5 with the test set. In addition, we applied the ensemble approach of best performing models and post-processing steps to the final results. Our experiments with the development set showed that our proposed model achieved a 0.537 pAP. On the test set, our system obtained a pAP score of 0.49

    Impact of diabetes continuing education on health care professionals’ attitudes towards diabetes care in a Yemeni city

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    Purpose: To evaluate the impact of a continuing education (CE) program on the attitudes of health care professionals (HCPs) towards diabetes care in Yemen.Methods: A pre- and post-intervention study was carried out in Mukalla City, Hadramout, Yemen and was offered to all physicians, pharmacists, and nurses registered in the Health Office in the Mukalla City. The HCPs were invited to attend a CE program. All participants filled out a questionnaire before the intervention (pre-test) that measured the attitudes of the participants towards diabetes. An interventional program was given in the form of a seminar, and participants were requested to complete the same questionnaire after the seminar.Results: A total of 73 HCPs attended the CE, including 19 pharmacists (26 %), 37 physicians (50.7 %), and 17 (23.3 %) nurses. The pre- and post-intervention changes in the questionnaire responses were significant only for attitude toward the values of blood glucose levels (p = 0.009) and attitude toward autonomy of diabetes patients (p = 0.023).Conclusion: HCPs in Mukalla City have positive attitudes toward diabetes. Physicians were more aware of the sequelae of diabetes than other healthcare professional groups with nurses showing the least understanding. Therefore, more emphasis should be placed upon designing education programs for diabetes specifically tailored for nurses and pharmacists.Keywords: Diabetes, Continuing education, Attitude, Health care professional

    The miR-17~92 Cluster: A Key Player in the Control of Inflammation during Rheumatoid Arthritis.:

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    MicroRNAs (miRNAs) are now recognized as essential regulators of gene expression in plants and animals. They potentially modulate the expression of multiple genes thereby enabling homeostatic settings in physiological conditions. Their role is also increasingly considered in many diseases in which deregulated epigenetic mechanisms induce aberrant gene expression. Work conducted in our laboratory has recently led to the identification of miRNAs essential for the control of inflammatory reactions that occur during rheumatoid arthritis (RA). In this review, we describe two such miRNAs, members of the miR-17 ∼ 92 cluster, which has been previously implicated in cancer. Based on our data and on predicted miRNA:mRNA interactions, we will extrapolate a model whereby the miR-17 ∼ 92 cluster appears as a global regulator of the Apoptosis Signal-Regulating Kinase 1 signalosome, a central actor in the inflammatory pathways activated during RA. We will also discuss the potential therapeutic outcomes emerging from this model
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