316 research outputs found

    Implicit yield function formulation for granular and rock-like materials

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    The constitutive modelling of granular, porous and quasi-brittle materials is based on yield (or damage) functions, which may exhibit features (for instance, lack of convexity, or branches where the values go to infinity, or false elastic domains) preventing the use of efficient return-mapping integration schemes. This problem is solved by proposing a general construction strategy to define an implicitly defined convex yield function starting from any convex yield surface. Based on this implicit definition of the yield function, a return-mapping integration scheme is implemented and tested for elastic-plastic (or -damaging) rate equations. The scheme is general and, although it introduces a numerical cost when compared to situations where the scheme is not needed, is demonstrated to perform correctly and accurately.Comment: 19 page

    Extracellular cell stress (heat shock) proteins - immune responses and disease: an overview

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    Extracellular cell stress proteins are highly conserved phylogenetically and have been shown to act as powerful signalling agonists and receptors for selected ligands in several different settings. They also act as immunostimulatory ‘danger signals’ for the innate and adaptive immune systems. Other studies have shown that cell stress proteins and the induction of immune reactivity to self-cell stress proteins can attenuate disease processes. Some proteins (e.g. Hsp60, Hsp70, gp96) exhibit both inflammatory and anti-inflammatory properties, depending on the context in which they encounter responding immune cells. The burgeoning literature reporting the presence of stress proteins in a range of biological fluids in healthy individuals/non-diseased settings, the association of extracellular stress protein levels with a plethora of clinical and pathological conditions and the selective expression of a membrane form of Hsp70 on cancer cells now supports the concept that extracellular cell stress proteins are involved in maintaining/regulating organismal homeostasis and in disease processes and phenotype. Cell stress proteins, therefore, form a biologically complex extracellular cell stress protein network having diverse biological, homeostatic and immunomodulatory properties, the understanding of which offers exciting opportunities for delivering novel approaches to predict, identify, diagnose, manage and treat disease

    Tumor-derived exosomes confer antigen-specific immunosuppression in a murine delayed-type hypersensitivity model

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    Exosomes are endosome-derived small membrane vesicles that are secreted by most cell types including tumor cells. Tumor-derived exosomes usually contain tumor antigens and have been used as a source of tumor antigens to stimulate anti-tumor immune responses. However, many reports also suggest that tumor-derived exosomes can facilitate tumor immune evasion through different mechanisms, most of which are antigen-independent. In the present study we used a mouse model of delayed-type hypersensitivity (DTH) and demonstrated that local administration of tumor-derived exosomes carrying the model antigen chicken ovalbumin (OVA) resulted in the suppression of DTH response in an antigen-specific manner. Analysis of exosome trafficking demonstrated that following local injection, tumor-derived exosomes were internalized by CD11c+ cells and transported to the draining LN. Exosome-mediated DTH suppression is associated with increased mRNA levels of TGF-β1 and IL-4 in the draining LN. The tumor-derived exosomes examined were also found to inhibit DC maturation. Taken together, our results suggest a role for tumor-derived exosomes in inducing tumor antigen-specific immunosuppression, possibly by modulating the function of APCs. © 2011 Yang et al

    Exosomes: Looking back three decades and into the future

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    Exosomes are extracellular membrane vesicles whose biogenesis by exocytosis of multivesicular endosomes was discovered in 1983. Since their discovery 30 years ago, it has become clear that exosomes contribute to many aspects of physiology and disease, including intercellular communication. We discuss the initial experiments that led to the discovery of exosomes and highlight some of the exciting current directions in the field

    Integration of decision support systems to improve decision support performance

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    Decision support system (DSS) is a well-established research and development area. Traditional isolated, stand-alone DSS has been recently facing new challenges. In order to improve the performance of DSS to meet the challenges, research has been actively carried out to develop integrated decision support systems (IDSS). This paper reviews the current research efforts with regard to the development of IDSS. The focus of the paper is on the integration aspect for IDSS through multiple perspectives, and the technologies that support this integration. More than 100 papers and software systems are discussed. Current research efforts and the development status of IDSS are explained, compared and classified. In addition, future trends and challenges in integration are outlined. The paper concludes that by addressing integration, better support will be provided to decision makers, with the expectation of both better decisions and improved decision making processes

    Lipodystrophy as a late effect after stem cell transplantation

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    Survivors of childhood cancer are at high risk of developing metabolic diseases in adulthood. Recently, several patients developing partial lipodystrophy following hematopoietic stem cell transplantation (HSCT) have been described. In this review, we summarize the cases described so far and discuss potential underlying mechanisms of the disease. The findings suggest that HSCT-associated lipodystrophies may be seen as a novel form of acquired lipodystrophy

    Ultrasound Liver Fibrosis Diagnosis using Multi-indicator guided Deep Neural Networks

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    Accurate analysis of the fibrosis stage plays very important roles in follow-up of patients with chronic hepatitis B infection. In this paper, a deep learning framework is presented for automatically liver fibrosis prediction. On contrary of previous works, our approach can take use of the information provided by multiple ultrasound images. An indicator-guided learning mechanism is further proposed to ease the training of the proposed model. This follows the workflow of clinical diagnosis and make the prediction procedure interpretable. To support the training, a dataset is well-collected which contains the ultrasound videos/images, indicators and labels of 229 patients. As demonstrated in the experimental results, our proposed model shows its effectiveness by achieving the state-of-the-art performance, specifically, the accuracy is 65.6%(20% higher than previous best).Comment: Jiali Liu and Wenxuan Wang are equal contributio

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    Gasless balloon laparoscopy

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    The concept of balloon laparoscopy (B-LSC) pursues the simplification of conventional diagnostic laparoscopy (LSC). The pneumoperitoneum is replaced by a transparent balloon, which is positioned in front of the optical system. It shall be shown that with this arrangement diagnostic LSC can be performed outside of the operating room without requiring general anesthesia.An inflatable balloon was developed for a 30°/3.5-mm rod lens. Intra-abdominally the balloon was expanded to a diameter of 30 mm by air insufflation, and B-LSC was performed. Twelve patients were examined in general anesthesia before laparoscopic surgery. Twelve patients were subjected to B-LSC fully awake or with sedation (midazolam or propofol/S-ketamine) as a “second-look” procedure by way of a flexible trocar (port) left in the abdominal wall at the end of previous operation. Eight patients have been first provided with a trocar under sedation (midazolam or propofol/S-ketamine) combined with local anesthesia, and B-LSC was performed before laparoscopic surgery.On a scale of 1–5, the general impression was rated 1.9, the navigability to the different abdominal organs 2.5, the resolution 1.5, the stability of the system optic/trocar 2.1, the suitability of the balloon format 1.9, and the stability of the balloon against lateral shear forces 2.4. The degree of painfulness of the examination was rated 2.8, the tolerance of the port 1.4, and the degree of painfulness of trocar placement at 2.5. On a scale of 1 to 3, the strain of the abdominal musculature was rated 1.4 and the obstruction by adhesions 1.7.B-LSC is technically practicable with good imaging qualities and without requiring pneumoperitoneum. It is tolerated in great extent under slight sedation and particularly well under deep sedation. The procedure is suitable for diagnostics of unclear abdominal conditions, as a second-look LSC and also as a staging LSC

    Digital single-operator pancreatoscopy for the treatment of symptomatic pancreatic duct stones: a prospective multicenter cohort trial

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    BACKGROUND  Digital single-operator pancreatoscopy (DSOP)-guided lithotripsy is a novel treatment modality for pancreatic endotherapy, with demonstrated technical success in retrospective series of between 88 % and 100 %. The aim of this prospective multicenter trial was to systematically evaluate DSOP in patients with chronic pancreatitis and symptomatic pancreatic duct stones. METHODS  Patients with symptomatic chronic pancreatitis and three or fewer stones ≥ 5mm in the main pancreatic duct (MPD) of the pancreatic head or body were included. The primary end point was complete stone clearance (CSC) in three or fewer treatment sessions with DSOP. Current guidelines recommend extracorporeal shock wave lithotripsy (ESWL) for MPD stones > 5 mm. A performance goal was developed to show that the CSC rate of MPD stones using DSOP was above what has been previously reported for ESWL. Secondary end points were pain relief measured with the Izbicki pain score (IPS), number of interventions, and serious adverse events (SAEs). RESULTS  40 chronic pancreatitis patients were included. CSC was achieved in 90 % of patients (36/40) on intention-to-treat analysis, after a mean (SD) of 1.36 (0.64) interventions (53 procedures in total). The mean (SD) baseline IPS decreased from 55.3 (46.2) to 10.9 (18.3). Overall pain relief was achieved in 82.4 % (28/34) after 6 months of follow-up, with complete pain relief in 61.8 % (21/34) and partial pain relief in 20.6 % (7/34). SAEs occurred in 12.5 % of patients (5/40), with all treated conservatively. CONCLUSION  DSOP-guided endotherapy is effective and safe for the treatment of symptomatic MPD stones in highly selected patients with chronic pancreatitis. It significantly reduces pain and could be considered as an alternative to standard ERCP techniques for MPD stone treatment in these patients
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