647 research outputs found

    The Complexity of Fixed-Height Patterned Tile Self-Assembly

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    We characterize the complexity of the PATS problem for patterns of fixed height and color count in variants of the model where seed glues are either chosen or fixed and identical (so-called non-uniform and uniform variants). We prove that both variants are NP-complete for patterns of height 2 or more and admit O(n)-time algorithms for patterns of height 1. We also prove that if the height and number of colors in the pattern is fixed, the non-uniform variant admits a O(n)-time algorithm while the uniform variant remains NP-complete. The NP-completeness results use a new reduction from a constrained version of a problem on finite state transducers.Comment: An abstract version appears in the proceedings of CIAA 201

    Federated Block Coordinate Descent Scheme for Learning Global and Personalized Models

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    In federated learning, models are learned from users' data that are held private in their edge devices, by aggregating them in the service provider's "cloud" to obtain a global model. Such global model is of great commercial value in, e.g., improving the customers' experience. In this paper we focus on two possible areas of improvement of the state of the art. First, we take the difference between user habits into account and propose a quadratic penalty-based formulation, for efficient learning of the global model that allows to personalize local models. Second, we address the latency issue associated with the heterogeneous training time on edge devices, by exploiting a hierarchical structure modeling communication not only between the cloud and edge devices, but also within the cloud. Specifically, we devise a tailored block coordinate descent-based computation scheme, accompanied with communication protocols for both the synchronous and asynchronous cloud settings. We characterize the theoretical convergence rate of the algorithm, and provide a variant that performs empirically better. We also prove that the asynchronous protocol, inspired by multi-agent consensus technique, has the potential for large gains in latency compared to a synchronous setting when the edge-device updates are intermittent. Finally, experimental results are provided that corroborate not only the theory, but also show that the system leads to faster convergence for personalized models on the edge devices, compared to the state of the art.Comment: 31 pages, 5 figures. Codes available at this url {https://github.com/REIYANG/FedBCD}. To appear in AAAI 202

    Effective eModule Design for First-Year Medical Student Anatomy Curricula

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    Introduction: It is critical to evaluate student experience with any newly integrated educational resource. In 2018, a Distal Upper Limb (DUL) Anatomy eModule was developed for first-year medical students at the University of Nebraska Medical Center, who have historically identified the DUL as a region of difficulty. This mixed methods study sought to (1) evaluate learner perception of the eModule relative to other resources, and (2) identify eModule content and features that students found valuable. Methods: The DUL eModule was made available to first-year medical students in 2019 (n= 132), 2020 (n=131), and 2021 (n=131) as a voluntary, supplemental resource. In 2019-2021, all eModule users were prompted to complete a post-eModule, pre-exam survey. In 2021, users were also asked to complete a post-eModule, post-exam survey. Both surveys included a combination of Likert-type and free-response questions. Results: In the post-eModule, pre-exam survey, a majority of students from all three years agreed or strongly agreed that the eModule was convenient, preferred compared to a textbook or didactic lecture, and applicable to the gross anatomy lab, though opinions were more split when comparing the eModule to studying from a gross specimen. In the post-eModule, post-exam survey, greater than 75% of students agreed or strongly agreed that the eModule prepared them to answer DUL exam questions, and was a useful adjunct to learning DUL anatomy. In the survey’s free response section, students cited support for the eModule’s cadaveric images, its ability to consolidate/organize information, and its two modes of use, though users reported a need for a figure legend to orient the user, and a desire for a learning evaluation integrated within the eModule. Discussion: While gross anatomy has historically been taught through in-person dissection, student demand for digital, remote learning resources is certain to grow. The findings of this mixed methods analysis will serve to guide anatomy faculty in developing effective digital resources for future novice anatomists.https://digitalcommons.unmc.edu/emet_posters/1034/thumbnail.jp

    Histamine H-3 Receptor Signaling Regulates the NLRP3 Inflammasome Activation in C2C12 Myocyte During Myogenic Differentiation

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    NLRP3 inflammasome has been implicated in impaired post-injury muscle healing and in muscle atrophy. Histamine receptors play an important role in inflammation, but the role of histamine H-3 receptor (H3R) in myocyte regeneration and in the regulation of NLRP3 inflammasome is not known. We studied the effects of H3R signaling on C2C12 myocyte viability, apoptosis, and tumor necrosis factor alpha (TNF alpha)-induced NLRP3 inflammasome activation during striated myogenic differentiation at three time points (days 0, 3, and 6). Expression of Nlrp3, interleukin-1 beta (IL-1 beta), and myogenesis markers were determined. TNF alpha reduced overall viability of C2C12 cells, and exposure to TNF alpha induced apoptosis of cells at D6. Activation of H3R had no effect on viability or apoptosis, whereas inhibition of H3R increased TNF alpha-induced apoptosis. Stimulation of C2C12 cells with TNF alpha increased Nlrp3 mRNA expression at D3 and D6. Moreover, TNF alpha reduced the expression of myogenesis markers MyoD1, Myogenin, and Myosin-2 at D3 and D6. H3R attenuated TNF alpha-induced expression of Nlrp3 and further inhibited the myogenesis marker expression; while H3R -blockage enhanced the proinflammatory effects of TNF alpha and increased the myogenesis marker expression. TNF alpha-induced secretion of mature IL-1 beta was dependent on the activation of the NLRP3 inflammasome, as shown by the reduced secretion of mature IL-1 beta upon treatment of the cells with the small molecule inhibitor of the NLRP3 inflammasome (MCC950). The activation of H3R reduced TNF alpha-induced IL-1 beta secretion, while the H3R blockage had an opposite effect. In conclusion, the modulation of H3R activity regulates the effects of TNF alpha on C2C12 myocyte differentiation and TNF alpha-induced activation of NLRP3 inflammasome. Thus, H3R signaling may represent a novel target for limiting postinjury muscle inflammation and muscle atrophy.Peer reviewe

    Luminescent Pt-II and Pt-IV Platinacycles with Anticancer Activity Against Multiplatinum-Resistant Metastatic CRC and CRPC Cell Models

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    Platinum-based chemotherapy persists to be the only effective therapeutic option against a wide variety of tumours. Nevertheless, the acquisition of platinum resistance is utterly common, ultimately cornering conventional platinum drugs to only palliative in many patients. Thus, encountering alternatives that are both effective and non-cross-resistant is urgent. In this work, we report the synthesis, reduction studies, and luminescent properties of a series of cyclometallated (C,N,N')PtIV compounds derived from amine- imine ligands, and their remarkable efficacy at the high nanomolar range and complete lack of cross57 resistance, as an intrinsic property of the platinacycle, against multiplatinum-resistant colorectal cancer (CRC) and castration-resistant prostate cancer (CRPC) metastatic cell lines generated for this work. We have also determined that the compounds are effective and selective for a broader cancer panel, including breast and lung cancer. Additionally, selected compounds have been further evaluated, finding a shift in their antiproliferative mechanism towards more cytotoxic and less cytostatic than cisplatin against cancer cells, being also able to oxidize cysteine residues and inhibit topoisomerase II, thereby holding great promise as future improved alternatives to conventional platinum drugs

    The lncRNA landscape of breast cancer reveals a role for DSCAM-AS1 in breast cancer progression.

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    Molecular classification of cancers into subtypes has resulted in an advance in our understanding of tumour biology and treatment response across multiple tumour types. However, to date, cancer profiling has largely focused on protein-coding genes, which comprise <1% of the genome. Here we leverage a compendium of 58,648 long noncoding RNAs (lncRNAs) to subtype 947 breast cancer samples. We show that lncRNA-based profiling categorizes breast tumours by their known molecular subtypes in breast cancer. We identify a cohort of breast cancer-associated and oestrogen-regulated lncRNAs, and investigate the role of the top prioritized oestrogen receptor (ER)-regulated lncRNA, DSCAM-AS1. We demonstrate that DSCAM-AS1 mediates tumour progression and tamoxifen resistance and identify hnRNPL as an interacting protein involved in the mechanism of DSCAM-AS1 action. By highlighting the role of DSCAM-AS1 in breast cancer biology and treatment resistance, this study provides insight into the potential clinical implications of lncRNAs in breast cancer

    Molybdenum Disulfide-Coated Lithium Vanadium Fluorophosphate Anode: Experiments and First-Principles Calculations

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    To develop a new anode material to meet the increasing demands of lithium-ion battery, MoS2 is used for the first time to modify the C/LiVPO4F anode to improve its lithium-storage performance between 3 and 0.01 V. Morphological observations reveal that the MoS2-modified C/LiVPO4F particles (M-LVPF) are wrapped by an amorphous carbon as interlayer and layered MoS2 as external surface. Charge–discharge tests show that M-LVPF delivers a high reversible capacity of 308 mAh g−1 at 50 mA g−1. After 300 cycles at 1.0 A g−1, a capacity retention of 98.7 % is observed. Moreover, it exhibits high rate capability with a specific capacity of 199 mAh g−1 at 1.6 A g−1. Electrochemical impedance spectroscopy tests indicate that the lithium-ion diffusion and charge-exchange reaction at the surface of M-LVPF are greatly enhanced. First-principles calculations for the MoS2 (001)/C/LiVPO4F (010) system demonstrate that the absorption of MoS2 on C/LiVPO4F is exothermic and spontaneous and that the electron transfer at the MoS2-absorbed C/LiVPO4F surface is enhanced.postprin

    Room-Temperature Phosphorescence and Efficient Singlet Oxygen Production by Cyclometalated Pt(II) Complexes with Aromatic Alkynyl Ligands

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    The synthesis of five novel cyclometalated platinum(II) compounds containing five different alkynyl-chromophores was achieved by the reaction of the previously synthesized Pt-Cl cyclometalated compound (1) with the corresponding RC (math)CH by a Sonogashira reaction. It was observed that the spectral and photophysical characteristics of the cyclometalated platinum(II) complexes (Pt-Ar) are essentially associated with the platinum-cyclometalated unit. Room-temperature emission of the Pt-Ar complexes was attributed to phosphorescence in agreement with DFT calculations. Broad nanosecond (ns)-transient absorption spectra were observed with decays approximately identical to those obtained from the emission of the triplet state. From the femtosecond-transient absorption (fs-TA) data, two main excited- state decay components were identified: one in the order of a few picoseconds was assigned to fast intersystem crossing to populate the triplet excited-state and the second (hundreds of ns) was associated with the decay of the transient triplet state. In general, efficient singlet oxygen photosensitization quantum yields were observed from the triplet state of these complexes
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