163 research outputs found

    NMR quantification of 16-O-methylcafestol and kahweol in Coffea canephora var. robusta beans from different geographical origins

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    Diterpenes have recently received a great deal of interest as tools to investigate the botanical origin of coffee. Specifically, kahweol has been proposed as a marker of Coffea arabica while 16-O-methylcafestol (16-OMC) is a Coffea canephora specific marker and its detection and quantification allow the authenticity of pure C. arabica roasted coffee blends to be assessed. In this study, we evaluated the possibility of the industrial use of the quantification of these diterpenes to assess the relative amounts of the two coffee species in blends. The content of 16-OMC and kahweol was determined in 78 samples (i.e., 39 green and the corresponding 39 roasted beans) of C. canephora from different geographical origins using a recently published NMR approach. Our results show a small natural variability in 16-OMC content for the Asian samples (average content = 1837 \ub1 113 mg/kg) while a much larger spread was found for the African samples (average content = 1744 \ub1 322 mg/kg). This large variability prevents the use of 16-OMC to quantify C. canephora in unknown roasted coffee blends. We also show that kahweol cannot be considered a specific C. arabica marker since it was detected almost all coffees and quantified in about 30% of the C. canephora samples

    Patient-specific blood flow simulations in the pulmonary bifurcation of patients with tetralogy of fallot

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    Dysfunction of the pulmonary valve and narrowing of the branch pulmonary arteries are common chronic complications in adult patients with tetralogy of Fallot; the most common cyanotic congenital heart disease with an estimate prevalence 1 in 3000 live births. Clinical consequences include, but are not limited to, abnormal lung development and elevated pulmonary vascular resistance. It is, therefore, crucial to better understand and characterise the haemodynamic environment in the pulmonary bifurcation to better diagnose and treat these patients. In this study, we have focused on investigating the blood flow dynamics in patient-specific geometries of the pulmonary bifurcation by means of computational models

    Current treatment strategies in managing side effects associated with domiciliary positive airway pressure (PAP) therapy for patients with sleep disordered breathing: A systematic review and meta-analysis

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    Sleep disordered breathing is commonly treated with positive airway pressure therapy. Positive airway pressure therapy is delivered via a tight-fitting mask with common side effects including: leak, ineffective treatment, residual sleep disordered breathing, eye irritation, nasal congestion, pressure ulcers and poor concordance with therapy. This systematic review and meta-analysis aimed to identify the effectiveness of current treatment strategies for managing side effects associated with positive airway pressure therapy. Five databases were searched and 10,809 articles were screened, with 36 articles included in the review. Studies investigated: dressings, nasal spray/douche, chin straps, heated humidification and interfaces. No intervention either improved or detrimentally affected: positive airway pressure concordance, Epworth Sleepiness Score, residual apnoea hypopnea index or interface leak. The review was limited by study heterogeneity, particularly for outcome measures. Additionally, patient demographics were not reported, making it difficult to apply the findings to a broad clinical population. This review highlights the paucity of evidence supporting treatment strategies to manage side effects of positive airway pressure therapy

    A Proof of Concept of a Non-Invasive Image-Based Material Characterization Method for Enhanced Patient-Specific Computational Modeling

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    PURPOSE: Computational models of cardiovascular structures rely on their accurate mechanical characterization. A validated method able to infer the material properties of patient-specific large vessels is currently lacking. The aim of the present study is to present a technique starting from the flow-area (QA) method to retrieve basic material properties from magnetic resonance (MR) imaging. METHODS: The proposed method was developed and tested, first, in silico and then in vitro. In silico, fluid-structure interaction (FSI) simulations of flow within a deformable pipe were run with varying elastic modules (E) between 0.5 and 32 MPa. The proposed QA-based formulation was assessed and modified based on the FSI results to retrieve E values. In vitro, a compliant phantom connected to a mock circulatory system was tested within MR scanning. Images of the phantom were acquired and post-processed according to the modified formulation to infer E of the phantom. Results of in vitro imaging assessment were verified against standard tensile test. RESULTS: In silico results from FSI simulations were used to derive the correction factor to the original formulation based on the geometrical and material characteristics. In vitro, the modified QA-based equation estimated an average E = 0.51 MPa, 2% different from the E derived from tensile tests (i.e. E = 0.50 MPa). CONCLUSION: This study presented promising results of an indirect and non-invasive method to establish elastic properties from solely MR images data, suggesting a potential image-based mechanical characterization of large blood vessels

    Maxillary Changes Following Facial Bipartition – A Three-Dimensional Quantification

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    INTRODUCTION: Children with Apert syndrome have hypertelorism and midfacial hypoplasia, which can be treated with facial bipartition (FB), often aided by rigid external distraction. The technique involves a midline osteotomy that lateralizes the maxillary segments, resulting in posterior cross-bites and midline diastema. Varying degrees of spontaneous realignment of the dental arches occurs postoperatively. This study aims to quantify these movements and assess whether they occur as part of a wider skeletal relapse or as dental compensation. METHODS: Patients who underwent FB and had high quality computed tomography scans at the preoperative stage, immediately postsurgery, and later postoperatively were reviewed. DICOM files were converted to three-dimensional bone meshes and anatomical point-to-point displacements were quantified using nonrigid iterative closest point registration. Displacements were visualized using arrow maps, thereby providing an overview of the movements of the facial skeleton and dentition. RESULTS: Five patients with Apert syndrome were included. In all cases, the arrow maps demonstrated initial significant anterior movement of the frontofacial segment coupled with medial rotation of the orbits and transverse divergence of the maxillary arches. The bony position following initial surgery was shown to be largely stable, with primary dentoalveolar relapse correcting the dental alignment. CONCLUSIONS: This study showed that spontaneous dental compensation occurs following FB without compromising the surgical result. It may be appropriate to delay active orthodontic for 6-months postoperatively until completion of this early compensatory phase

    The 3D skull 0–4 years: A validated, generative, statistical shape model

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    BACKGROUND: This study aims to capture the 3D shape of the human skull in a healthy paediatric population (0–4 years old) and construct a generative statistical shape model. METHODS: The skull bones of 178 healthy children (55% male, 20.8 ± 12.9 months) were reconstructed from computed tomography (CT) images. 29 anatomical landmarks were placed on the 3D skull reconstructions. Rotation, translation and size were removed, and all skull meshes were placed in dense correspondence using a dimensionless skull mesh template and a non-rigid iterative closest point algorithm. A 3D morphable model (3DMM) was created using principal component analysis, and intrinsically and geometrically validated with anthropometric measurements. Synthetic skull instances were generated exploiting the 3DMM and validated by comparison of the anthropometric measurements with the selected input population. RESULTS: The 3DMM of the paediatric skull 0–4 years was successfully constructed. The model was reasonably compact - 90% of the model shape variance was captured within the first 10 principal components. The generalisation error, quantifying the ability of the 3DMM to represent shape instances not encountered during training, was 0.47 mm when all model components were used. The specificity value was <0.7 mm demonstrating that novel skull instances generated by the model are realistic. The 3DMM mean shape was representative of the selected population (differences <2%). Overall, good agreement was observed in the anthropometric measures extracted from the selected population, and compared to normative literature data (max difference in the intertemporal distance) and to the synthetic generated cases. CONCLUSION: This study presents a reliable statistical shape model of the paediatric skull 0–4 years that adheres to known skull morphometric measures, can accurately represent unseen skull samples not used during model construction and can generate novel realistic skull instances, thus presenting a solution to limited availability of normative data in this field

    Evaluating inhibition conditions in high-solids anaerobic digestion of organic fraction of municipal solid waste

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    High-solids anaerobic digestion (HSAD) processes, when applied to different types of organic fractions of municipal solid waste (OFMSW), may easily be subjected to inhibition due to organic overloading. In this study, a new approach for predicting these phenomena was proposed based on the estimation of the putrescibility (oxygen consumption in 20 h biodegradation, OD20) of the organic mixtures undergoing the HSAD process. Different wastes exhibiting different putrescibility were subjected to lab-scale batch-HSAD. Measuring the organic loading (OL) as volatile solids (VS) was found unsuitable for predicting overload inhibition, because similar VS contents corresponded to both inhibited and successful trials. Instead, the OL calculated as OD20 was a very good indicator of the inhibiting conditions (inhibition started for OD20 > 17\u201318 g O2 kg^(-1)). This new method of predicting inhibition in the HSAD process of diverse OFMSW may be useful for developing a correct approach to the technology in very different contexts

    Convolutional mesh autoencoders for the 3-dimensional identification of FGFR-related craniosynostosis

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    Clinical diagnosis of craniofacial anomalies requires expert knowledge. Recent studies have shown that artificial intelligence (AI) based facial analysis can match the diagnostic capabilities of expert clinicians in syndrome identification. In general, these systems use 2D images and analyse texture and colour. They are powerful tools for photographic analysis but are not suitable for use with medical imaging modalities such as ultrasound, MRI or CT, and are unable to take shape information into consideration when making a diagnostic prediction. 3D morphable models (3DMMs), and their recently proposed successors, mesh autoencoders, analyse surface topography rather than texture enabling analysis from photography and all common medical imaging modalities and present an alternative to image-based analysis. We present a craniofacial analysis framework for syndrome identification using Convolutional Mesh Autoencoders (CMAs). The models were trained using 3D photographs of the general population (LSFM and LYHM), computed tomography data (CT) scans from healthy infants and patients with 3 genetically distinct craniofacial syndromes (Muenke, Crouzon, Apert). Machine diagnosis outperformed expert clinical diagnosis with an accuracy of 99.98%, sensitivity of 99.95% and specificity of 100%. The diagnostic precision of this technique supports its potential inclusion in clinical decision support systems. Its reliance on 3D topography characterisation make it suitable for AI assisted diagnosis in medical imaging as well as photographic analysis in the clinical setting

    Grape berry responses to sequential flooding and heatwave events: a physiological, transcriptional, and metabolic overview

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    Grapevine cultivation, such as the whole horticulture, is currently challenged by several factors, among which the extreme weather events occurring under the climate change scenario are the most relevant. Within this context, the present study aims at characterizing at the berry level the physiological response of Vitis vinifera cv. Sauvignon Blanc to sequential stresses simulated under a semi-controlled environment: flooding at bud-break followed by multiple summer stress (drought plus heatwave) occurring at pre-vèraison. Transcriptomic and metabolomic assessments were performed through RNASeq and NMR, respectively. A comprehensive hormone profiling was also carried out. Results pointed out a different response to the heatwave in the two situations. Flooding caused a developmental advance, determining a different physiological background in the berry, thus affecting its response to the summer stress at both transcriptional levels, with the upregulation of genes involved in oxidative stress responses, and metabolic level, with the increase in osmoprotectants, such as proline and other amino acids. In conclusion, sequential stress, including a flooding event at bud-break followed by a summer heatwave, may impact phenological development and berry ripening, with possible consequences on berry and wine quality. A berry physiological model is presented that may support the development of sustainable vineyard management solutions to improve the water use efficiency and adaptation capacity of actual viticultural systems to future scenario
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