117 research outputs found

    New findings in a 400 million-year-old Devonian placoderm shed light on jaw structure and function in basal gnathostomes

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    Arthodire placoderms have been proposed as the sister group of Chinese 'maxillate' placoderms plus all the more crownward gnathostomes. These basal groups provide key information for understanding the early evolution of jaws. Here, we test previous assumptions about placoderm jaw structure and function by using high-resolution computed tomography, digital dissection, and enlarged 3D printouts on a unique articulated 400 million-year-old buchanosteid arthrodire. The upper jaw has a double ethmoid and a palatobasal connection, but no otic connection; the dermal bone attachment for the quadrate is different to other placoderms. A separately ossified cartilage behind the mandibular joint is comparable to the interhyal of osteichthyans. Two articular facets on the braincase associated with the hyomandibular nerve foramen supported a possible epihyal element and a separate opercular cartilage. Reassembling and manipulating 3D printouts demonstrates the limits of jaw kenetics. The new evidence indicates unrecognized similarities in jaw structure between arthrodires and osteichthyans, and will help to clarify the sequence of character acquisition in the evolution of basal gnathostome groups. New details on the hyoid arch will help to reformulate characters that are key in the heated debate of placoderm monophyly or paraphyly

    CT investigations of Australian Devonian fossil fishes, and the application of 3D segmentation and modelling in vertebrate morphology

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    This thesis by compilation covers four publications, which together demonstrate and apply computed tomography (CT) data, three-dimensional (3D) segmentation, and 3D printing, for the non-destructive high-resolution detection of internal structure in early vertebrate fossils. Paper 1 (published 2019) studied the tetrapodomorph fish, Gogonasus, a three dimensionally well-preserved acid etched Devonian sarcopterygian. 3D modelling and printing were used for the reconstruction of its shoulder girdle and opercular series. A close fit of the opercular series against the upper bones of the shoulder girdle required a more horizontally aligned anocleithrum, supracleithrum and post-temporal than in previous reconstructions. Subopercular bone 2 is partly covered the clavicle, and the ascending process of the clavicle, and the ventral process of the anocleithrum, do not fit closely inside the cleithrum, suggesting they may have functioned for ligamentous attachment. A rugose area on the anocleithral process has a similar relative position to muscle ligament attachements in the shoulder girdle of various living actinopterygians. The manipulation of 3D models demonstrates testing of morphological fit for extremely fragile acid-etched bones. Paper 2 (published 2017) dealt with an articulated Devonian placoderm. Micro CT, 3D segmentation, and enlarged 3D models of a buchanosteid arthrodire, demonstrated a double ethmoid and a palatobasal connection for the palatoquadrate, but no otic connection. A separately ossified cartilage behind the mandibular joint is comparable to the interhyal of osteichthyans. Two articular facets on the braincase associated with the hyomandibular nerve foramen supported a possible epihyal element and a separate opercular cartilage. Reassembling 3D printouts demonstrates the limits of jaw kinetics. New details on the hyoid arch will help to reformulate characters that are key in the heated debate of placoderm monophyly or paraphyly. Paper 3 (published 2019) describes the detailed morphology of the three gnathal elements of the same specimen as on the previous paper, giving insights into the morphology and organization of the dentition in arthrodires. Arthrodire placoderms, as a possible sister group of Chinese maxillate placoderms plus crown gnathostomes, provide important information regarding early evolution of jaws and teeth. In displaying numerous denticle rows, the gnathal element morphology is different from the much-reduced denticulation of higher brachythoracid arthrodires. Ossification centres are anterolateral on the anterior supragnathal (attached to the braincase), anteromesial on the posterior supragnathal (attached to the palatoquadrate), and in the central part of the biting portion of the infragnathal (attached to the meckelian cartilage). The infragnathal shows no evidence of two ossification centres, as has been interpreted for more advanced arthrodires. The new evidence gives insights into the primitive arthrodire condition for comparison with the dermal jaw bones of Chinese 'maxillate' placoderms that have been homologised with the premaxilla, maxilla, and dentary of osteichthyans. Paper 4 (published 2020) summarizes the relationship between different modules of Drishti, an open-source volume exploration, rendering and three-dimensional segmentation software program that was used in the previous three published papers. A new version (Drishti v2.7) is presented, with a new tool for thresholding volume data (i.e. gradient thresholding). A protocol is introduced for performing three-dimensional segmentation using the new 3D Freeform Painter tool. In Drishti Paint, these new tools and workflow enable more accurate and precise digital reconstruction, 3D modelling and three-dimensional printing/modelling results. Scan data from the buchanosteus arthrodire (Paper 2 and 3) was used as a case study but published procedure is widely applicable in biological, medical and industrial research

    Contrastive Learning Method for Sequential Recommendation based on Multi-Intention Disentanglement

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    Sequential recommendation is one of the important branches of recommender system, aiming to achieve personalized recommended items for the future through the analysis and prediction of users' ordered historical interactive behaviors. However, along with the growth of the user volume and the increasingly rich behavioral information, how to understand and disentangle the user's interactive multi-intention effectively also poses challenges to behavior prediction and sequential recommendation. In light of these challenges, we propose a Contrastive Learning sequential recommendation method based on Multi-Intention Disentanglement (MIDCL). In our work, intentions are recognized as dynamic and diverse, and user behaviors are often driven by current multi-intentions, which means that the model needs to not only mine the most relevant implicit intention for each user, but also impair the influence from irrelevant intentions. Therefore, we choose Variational Auto-Encoder (VAE) to realize the disentanglement of users' multi-intentions. We propose two types of contrastive learning paradigms for finding the most relevant user's interactive intention, and maximizing the mutual information of positive sample pairs, respectively. Experimental results show that MIDCL not only has significant superiority over most existing baseline methods, but also brings a more interpretable case to the research about intention-based prediction and recommendation

    Three-dimensional segmentation of computed tomography data using Drishti Paint: new tools and developments

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    Computed tomography (CT) has become very widely used in scientific and medical research and industry for its non-destructive and high-resolution means of detecting internal structure. Three-dimensional segmentation of computed tomography data sheds light on internal features of target objects. Three-dimensional segmentation of CT data is supported by various well-established software programs, but the powerful functionalities and capabilities of open-source software have not been fully revealed. Here, we present a new release of the open-source volume exploration, rendering and three-dimensional segmentation software, Drishti v. 2.7. We introduce a new tool for thresholding volume data (i.e. gradient thresholding) and a protocol for performing three-dimensional segmentation using the 3D Freeform Painter tool. These new tools and workflow enable more accurate and precise digital reconstruction, three-dimensional modelling and three-dimensional printing results. We use scan data of a fossil fish as a case study, but our procedure is widely applicable in biological, medical and industrial research.This research was funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDB26000000) and the National Natural Science Foundation of China (grant no. 41872023). Y.H. was supported by a Postgraduate Research Scholarship at the Research School of Physics, Australian National University. The development of Drishti is supported by National Computational Infrastructure, Australian National University. CT scans and three-dimensional printing are supported by the Department of Applied Mathematics, Research School of Physics and ANU CT Lab, with funding support from Prof. T. Senden and Australian Research Council Discovery Grant DP160102460

    Emotional Rendering of 3D Indoor Scene with Chinese Elements

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    One of the challenging tasks is to use computer technology to automatically design a virtual indoor scene that both satisfies realness and matches the target emotion. The subjective nature of emotions brings uncertainty of results. At present, there is a lack of approach to identify and evaluate emotion of indoor scenes. In addition, under the premise of fully considering emotional appeals, the authenticity of scene is also one of important factors in indoor scene design. Aiming at above problems, a novel optimization algorithm combining Chinese elements for indoor scenes rendering is proposed. Firstly, an emotion classifier is trained to identify and evaluate the emotion with the features extracted via deep learning from a indoor scene dataset containing 25000 images. Secondly, in order to ensure the authenticity of rendering results, an algorithm is proposed to evaluate how realistic the colors of the objects’ textures. Next, an algorithm is designed to render indoor scene automatically according to the target emotion. Then, a style transfer algorithm integrating with Chinese elements is used to carry out fine-grained refinement processing on the furnishings in an indoor scene, improve the spatial connotation, cultural connotation and emotional expression of rendering results, and enhance the visual appeal. Finally, the approach is tested in four indoor scenes, and the correctness and effectiveness of the approach are verified through statistical analysis of results and user survey data

    An in silico framework for integrating epidemiologic and genetic evidence with health care applications: ventilation-related pneumothorax as a case illustration

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    OBJECTIVE: To illustrate an in silico integration of epidemiologic and genetic evidence that is being developed at the Center for Devices and Radiological Health/US Food and Drug Administration as part of regulatory research on postmarket device performance. In addition to using conventional epidemiologic evidence from registries, this innovative approach explores the vast potential of open-access omics databases for identifying genetic evidence pertaining to devices. MATERIAL AND METHODS: A retrospective analysis of Agency for Healthcare Research and Quality (AHRQ)/Healthcare Cost and Utilization Project (HCUPNet) data (2002-2011) was focused on the ventilation-related iatrogenic pneumothorax (Vent-IP) outcome in discharges with mechanical ventilation (MV) and continuous positive airway pressure (CPAP). The derived epidemiologic evidence was analyzed in conjunction with pre-existing genomic data from Gene Expression Omnibus/National Center for Biotechnology Information and other databases. RESULTS: AHRQ/HCUPNet epidemiologic evidence showed that annual occurrence of Vent-IP did not decrease over a decade. While the Vent-IP risk associated with noninvasive CPAP comprised about 0.5%, the Vent-IP risk due to longer-term MV reached 2%. Along with MV posing an independent risk for Vent-IP, female sex and white race were found to be effect modifiers, resulting in the highest Vent-IP risk among mechanically ventilated white females. The Vent-IP risk was also potentiated by comorbidities associated with spontaneous pneumothorax (SP) and fibrosis. Consistent with the epidemiologic evidence, expression profiling in a number of animal models showed that the expression of several collagens and other SP/fibrosis-related genes was modified by ventilation settings. CONCLUSION: Integration of complementary genetic evidence into epidemiologic analysis can lead to a cost- and time-efficient discovery of the risk predictors and markers and thus can facilitate more efficient marker-based evaluation of medical product performance

    The association and dose–response relationship between dietary intake of α-linolenic acid and risk of CHD: a systematic review and meta-analysis of cohort studies

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    Abstract Previous studies show inconsistent associations between α -linolenic acid (ALA) and risk of CHD. We aimed to examine an aggregate association between ALA intake and risk of CHD, and assess for any dose–response relationship. We searched the PubMed, EMBASE and Web of Science databases for prospective cohort studies examining associations between ALA intake and CHD, including composite CHD and fatal CHD. Data were pooled using random-effects meta-analysis models, comparing the highest category of ALA intake with the lowest across studies. Subgroup analysis was conducted based on study design, geographic region, age and sex. For dose–response analyses, we used two-stage random-effects dose–response models. In all, fourteen studies of thirteen cohorts were identified and included in the meta-analysis. The pooled results showed that higher ALA intake was associated with modest reduced risk of composite CHD (risk ratios (RR)=0·91; 95 % CI 0·85, 0·97) and fatal CHD (RR=0·85; 95 % CI 0·75, 0·96). The analysis showed a J-shaped relationship between ALA intake and relative risk of composite CHD ( χ 2 =21·95, P <0·001). Compared with people without ALA intake, only people with ALA intake <1·4 g/d showed reduced risk of composite CHD. ALA intake was linearly associated with fatal CHD – every 1 g/d increase in ALA intake was associated with a 12 % decrease in fatal CHD risk (95 % CI −0·21, −0·04). Though a higher dietary ALA intake was associated with reduced risk of composite and fatal CHD, the excess composite CHD risk at higher ALA intakes warrants further investigation, especially through randomised controlled trials

    Ultrasound-guided microwave ablation in the treatment of recurrent primary hyperparathyroidism in a patient with MEN1: a case report

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    BackgroundMultiple endocrine neoplasia type 1 (MEN1) is an inherited endocrine syndrome caused by the mutation in the tumor suppressor gene MEN1. The recurrence rate of primary hyperparathyroidism (PHPT) in patients with MEN1 after parathyroidectomy remains high, and the management of recurrent hyperparathyroidism is still challenging.Case presentationWe reported a 44-year-old woman with MEN1 combined with PHPT who was diagnosed through genetic screening of the patient and her family members. After parathyroidectomy to remove one parathyroid gland, the patient suffered from persistent high levels of serum calcium and parathyroid hormone, which returned to normal at up to 8 months after ultrasound-guided microwave ablation (MWA) for bilateral parathyroid glands, suggesting an acceptable short-term prognosis.ConclusionUltrasound-guided MWA for parathyroid nodules may be an effective therapeutic strategy for recurrent PHPT in MEN1 patients
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