1,342 research outputs found

    Model-guided design of ligand-regulated RNAi for programmable control of gene expression

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    Progress in constructing biological networks will rely on the development of more advanced components that can be predictably modified to yield optimal system performance. We have engineered an RNA-based platform, which we call an shRNA switch, that provides for integrated ligand control of RNA interference (RNAi) by modular coupling of an aptamer, competing strand, and small hairpin (sh) RNA stem into a single component that links ligand concentration and target gene expression levels. A combined experimental and mathematical modelling approach identified multiple tuning strategies and moves towards a predictable framework for the forward design of shRNA switches. The utility of our platform is highlighted by the demonstration of fine-tuning, multi-input control, and model-guided design of shRNA switches with an optimized dynamic range. Thus, shRNA switches can serve as an advanced component for the construction of complex biological systems and offer a controlled means of activating RNAi in disease therapeutics

    Pancreatic acinar cell carcinoma: A review on molecular profiling of patient tumors

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    Pancreatic carcinomas with acinar differentiation are rare, accounting for 1%-2% of adult pancreatic tumors; they include pancreatic acinar cell carcinoma (PACC), pancreatoblastoma, and carcinomas of mixed differentiation. Patients with PACC have a prognosis better than pancreatic ductal adenocarcinomas but worse than pancreatic neuroendocrine tumors. Reports of overall survival range from 18 to 47 mo. A literature review on PACCs included comprehensive genomic profiling and whole exome sequencing on a series of more than 70 patients as well as other diagnostic studies including immunohistochemistry. Surgical resection of PACC is the preferred treatment for localized and resectable tumors. The efficacy of adjuvant treatment is unclear. Metastatic PACCs are generally not curable and treated with systemic chemotherapy. They are moderately responsive to chemotherapy with different regimens showing various degrees of response in case reports/series. Most of these regimens were developed to treat patients with pancreatic ductal adenocarcinomas or colorectal adenocarcinomas. Review of PACC’s molecular profiling showed a number of gene alterations such as: SMAD4, BRAF, BRCA2, TP53, RB1, MEN1, JAK-1, BRCA-1, BRCA-2, and DNA mismatch repair abnormalities. PACCs had multiple somatic mutations with some targetable with available drugs. Therefore, molecular profiling of PACC should be an option for patients with refractory PACC

    A Review of Power Converters for Ships Electrification

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    Fully electric ships have become popular to meet the demand for emission-free transportation and improve ships' functionality, reliability, and efficiency. Previous studies reviewed the shipboard power systems, the different types of shipboard energy storage devices, and the influences of the shore-to-ship connection on ports' electrical grid. However, the converter topologies used in the electrification of ships have received very little attention. This article presents a comprehensive topological review of currently available shore-to-ship and shipboard power converters in the literature and on the market. The main goal is to anticipate future trends and potential challenges to stimulate research to accelerate more efficient and reliable electric ships

    Under Seawater Capacitive Power Transfer for Maritime Charging Applications

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    Underwater capacitive power transfer (CPT) can provide an inexpensive and light electric charging solution with good misalignment tolerance for unmanned maritime vehicles. This paper investigates the effect of the changing of the frequency and the distance on the power transfer and overall efficiency of the underwater CPT system, considering the dielectric losses of the medium. It also proposes and validates a mathematical model for calculating the maximum available efficiency of the system. Using series compensations, the proposed CPT can transfer 48 W at 500 mm, 48 V input voltage, 516 kHz, and 54%

    Conformal Transformation Analysis of Capacitive Wireless Charging

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    This paper studies the capacitive coupling in a capacitive power transfer (CPT) system designed for charging applications. It proposes mathematical models using the conformal transformation for calculating air-gapped and underwater capacitance and verifies the proposed models using COMSOL multiphysics and measurements. The measured results show that we can achieve nano-farad capacitance ranges if we submerge the capacitor in seawater. The seawater’s capacitance slightly changes when we increase the gap distance or the operating frequency. As the under seawater CPT system can be an attractive option for loosely-coupled charging applications, we further examine the system by focusing on the crosscoupling effects. The results show that the cross-coupling between the plate degrades the system’s power transfer capability and efficiency. With negligible cross-coupling effects, the system gives 129 W output power at an efficiency of 81.2%

    COVID-19 severity and vaccine breakthrough infections in idiopathic inflammatory myopathies, other systemic autoimmune and inflammatory diseases, and healthy controls: a multicenter cross-sectional study from the COVID-19 Vaccination in Autoimmune Diseases (COVAD) survey

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    OBJECTIVES: We aimed to compare the spectrum and severity of COVID-19 and vaccine breakthrough infections (BIs) among patients with IIMs, other systemic autoimmune and inflammatory diseases (SAIDs), and healthy controls (HCs). METHODS: This is a cross-sectional study with data from the COVAD study, a self-reported online global survey that collected demographics, COVID-19 history, and vaccination details from April to September 2021. Adult patients with at least one COVID-19 vaccine dose were included. BIs were defined as infections occurring > 2 weeks after any dose of vaccine. Characteristics associated with BI were analyzed with a multivariate regression analysis. RESULTS: Among 10,900 respondents [42 (30-55) years, 74%-females, 45%-Caucasians] HCs were (47%), SAIDs (42%) and IIMs (11%). Patients with IIMs reported fewer COVID-19 cases before vaccination (6.2%-IIM vs 10.5%-SAIDs vs 14.6%-HC; OR = 0.6, 95% CI 0.4-0.8, and OR = 0.3, 95% CI 0.2-0.5, respectively). BIs were uncommon (1.4%-IIM; 1.9%-SAIDs; 3.2%-HC) and occurred in 17 IIM patients, 13 of whom were on immunosuppressants, and 3(18%) required hospitalization. All-cause hospitalization was higher in patients with IIM compared to HCs [23 (30%) vs 59 (8%), OR = 2.5, 95% CI 1.2-5.1 before vaccination, and 3 (18%) vs 9 (5%), OR = 2.6, 95% CI 1.3-5.3 in BI]. In a multivariate regression analysis, age 30-60 years was associated with a lower odds of BI (OR = 0.7, 95% CI 0.5-1.0), while the use of immunosuppressants had a higher odds of BI (OR = 1.6, 95% CI 1.1-2.7). CONCLUSIONS: Patients with IIMs reported fewer COVID-19 cases than HCs and other SAIDs, but had higher odds of all-cause hospitalization from COVID-19 than HCs. BIs were associated with the use of immunosuppressants and were uncommon in IIMs

    Design Considerations of Capacitive Power Transfer Systems

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    Capacitive power transfer (CPT) is a near-field wireless power transfer (WPT) technology that has attracted attention in different charging applications. By utilizing electric fields, CPT gives charging systems advantages in terms of cost, weight, flexibility, and mobility. This paper surveys a number of empirical published works in a period between 2015 and 2023. Additionally, it discusses theoretical and practical design considerations of a CPT system to understand and improve the technology and its applications. The paper studies the one- and two-port measuring approaches using vector network analyzers to determine the coupling parameters and compares the measurements to the simulated values using COMSOL Multiphysics ©. The two-port approach gives more accurate results than the one-port approach. The paper designs and tests a 13.56MHz CPT system using the two-port measurement results. The system transfers 100W at 87.4% efficiency and 30mm separation distance. Lastly, the paper discusses the design limitations and challenges of the CPT systems, aiming to emphasize the design obstacles that can drive the advancement of the CPT systems for wireless charging applications

    Laparoscopic Laser Speckle Contrast Imaging Can Visualize Anastomotic Perfusion:A Demonstration in a Porcine Model

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    Background: Intestinal resection causes inevitable vascular damage, which cannot always be seen during an intraoperative clinical assessment of local intestinal perfusion. If left unaltered, impaired perfusion can lead to complications, such as anastomotic leakage (AL). Therefore, we demonstrate the use of a novel laparoscopic laser speckle contrast imaging (LSCI)-based approach in order to assess local intestinal perfusion during the construction of intestinal anastomoses. Methods: Three segments were isolated from the small intestine of a pig, while the perfusion of each was compromised by coagulating 7–8 mesenteric arteries. Both clinical assessments and LSCI were used to detect the induced perfusion deficits and to subsequently guide a transection in either a well perfused, marginally perfused, or poorly perfused tissue area within the segment. Bowel ends were then utilized for the creation of three differently perfused anastomoses: well perfused/well perfused (anastomosis segment 1), well perfused/poorly perfused (anastomosis segment 2), and poorly perfused/poorly perfused (anastomosis segment 3). After construction of the anastomoses, a final perfusion assessment using both clinical assessment and LSCI was executed in order to evaluate the vascular viability of the anastomosis. Results: Laparoscopic LSCI enabled continuous assessment of local intestinal perfusion and allowed for detection of perfusion deficits in real time. The imaging feedback precisely guided the surgical procedure, and, when evaluating the final anastomotic perfusion, LSCI was able to visualize the varying degrees of perfusion, whereas standard clinical assessment yielded only minor differences in visual appearance of the tissue. Conclusions: In this technical note, we demonstrate a novel LSCI-based approach for intraoperative perfusion assessment. With its ability to continuously visualize perfusion in real time, laparoscopic LSCI has significant potential for the optimization of anastomotic surgery in the near future

    The interplay of microscopic and mesoscopic structure in complex networks

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    Not all nodes in a network are created equal. Differences and similarities exist at both individual node and group levels. Disentangling single node from group properties is crucial for network modeling and structural inference. Based on unbiased generative probabilistic exponential random graph models and employing distributive message passing techniques, we present an efficient algorithm that allows one to separate the contributions of individual nodes and groups of nodes to the network structure. This leads to improved detection accuracy of latent class structure in real world data sets compared to models that focus on group structure alone. Furthermore, the inclusion of hitherto neglected group specific effects in models used to assess the statistical significance of small subgraph (motif) distributions in networks may be sufficient to explain most of the observed statistics. We show the predictive power of such generative models in forecasting putative gene-disease associations in the Online Mendelian Inheritance in Man (OMIM) database. The approach is suitable for both directed and undirected uni-partite as well as for bipartite networks
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