404 research outputs found

    Parametric testing of a linearly driven Stirling cryogenic refrigerator

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    The parametric testing of a novel Stirling cycle cryogenic refrigerator which incorporates electromagnetic bearings, clearance seals and electronically controlled linear motion was studied. The last feature, which involves the use of two linear motors, position transducers and a highly accurate electronic feedback network, produces the system capability which forms the basis for the tests. The test results provide designers with an understanding of the basic operation of the Stirling cycle and give potential users some indication of the capabilities of this refrigerator under off design conditions

    Family Dynamics and Personal Strengths among Dementia Caregivers in Argentina

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    This study examined whether healthier family dynamics were associated with higher personal strengths of resilience, sense of coherence, and optimism among dementia caregivers in Argentina. Caregivers are usually required to assist individuals with dementia, and family members have typically fulfilled that role. Personal strengths such as resilience, sense of coherence, and optimism have been shown to protect caregivers from some of the negative experiences of providing care, though the family-related variables associated with these personal strengths are largely unknown. Hierarchical multiple regressions investigated the extent to which family dynamics variables are associated with each of the caregiver personal strengths after controlling for demographic and caregiver characteristics. A sample of 105 caregivers from Argentina completed a set of questionnaires during a neurologist visit. Family dynamics explained 32% of the variance in resilience and 39% of the variance in sense of coherence. Greater family empathy and decreased family problems were uniquely associated with higher resilience. Greater communication and decreased family problems were uniquely associated with higher sense of coherence. Optimism was not found to be significantly associated with family dynamics. These results suggest that caregiver intervention research focused on the family may help improve caregiver personal strengths in Argentina and other Latin American countries

    An Intelligent Advisor for City Traffic Policies

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    Nowadays, city streets are populated not only by private vehicles but also by public transport, fleets of workers, and deliveries. Since each vehicle class has a maximum cargo capacity, we study in this article how authorities could improve the road traffic by endorsing long term policies to change the different vehicle proportions: sedans, minivans, full size vans, trucks, and motorbikes, without losing the ability of moving cargo throughout the city. We have performed our study in a realistic scenario (map, road traffic characteristics, and number of vehicles) of the city of Malaga and captured the many details into the SUMO microsimulator. After analyzing the relationship between travel times, emissions, and fuel consumption, we have defined a multiobjective optimization problem to be solved, so as to minimize these city metrics. Our results provide a scientific evidence that we can improve the delivery of goods in the city by reducing the number of heavy duty vehicles and fostering the use of vans instead.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This research has been partially funded by the Spanish MINECO and FEDER projects TIN2014-57341-R, TIN2016-81766-REDT, and TIN2017-88213-R. University of Malaga, Andalucia TECH. Daniel H. Stolfi is supported by a FPU grant (FPU13/00954) from the Spanish MECD. Christian Cintrano is supported by a FPI grant (BES-2015-074805) from Spanish MINECO

    Embodied Interactions with E-Textiles and the Internet of Sounds for Performing Arts

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    This paper presents initial steps towards the design of an embedded system for body-centric sonic performance. The proposed prototyping system allows performers to manipulate sounds through gestural interactions captured by textile wearable sensors. The e-textile sensor data control, in real-time, audio synthesis algorithms working with content from Audio Commons, a novel web-based ecosystem for repurposing crowd-sourced audio. The system enables creative embodied music interactions by combining seamless physical e-textiles with web-based digital audio technologies

    Folate-Functionalization Enhances Cytotoxicity of Multivalent DNA Nanocages on Triple-Negative Breast Cancer Cells

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    DNA is an excellent programmable polymer for the generation of self-assembled multivalent nanostructures useful for biomedical applications. Herein, we developed (i) folate-functionalized nanocages (Fol-NC), very efficiently internalized by tumor cells overexpressing the alpha isoform of the folate receptor; (ii) AS1411-linked nanocages (Apt-NC), internalized through nucleolin, a protein overexpressed in the cell surface of many types of cancers; and (iii) nanostructures that harbor both folate and AS1411 aptamer functionalization (Fol-Apt-NC). We analyzed the specific miRNA silencing activity of all types of nanostructures harboring miRNA sequestering sequences complementary to miR-21 and the cytotoxic effect when loaded with doxorubicin in a drug-resistant triple-negative breast cancer cell line. We demonstrate that the presence of folate as a targeting ligand increases the efficiency in miR-21 silencing compared to nanocages functionalized with AS1411. Double-functionalized nanocages (Fol-Apt-NC), loaded with doxorubicin, resulted in an increase of over 51% of the cytotoxic effect on MDA-MB-231 cells compared to free doxorubicin, demonstrating, besides selectivity, the ability of nanocages to overcome Dox chemoresistance. The higher efficiency of the folate-functionalized nanocages is due to the way of entrance, which induces more than four times higher intracellular stability and indicates that the folate-mediated route of cell entry is more efficient than the nucleolin-mediated one when both folate and AS1411 modifications are present

    A Cohort Study Assessing the Impact of Anki as a Spaced Repetition Tool on Academic Performance in Medical School

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    Introduction Anki is an application that capitalizes upon the techniques of spaced repetition and is increasingly utilized by medical students for examination preparation. This study examines the impact of Anki usage in a medical school curriculum on academic performance. Secondary objectives analyzed individual Anki utilization and a qualitative assessment of Anki use. Methods A cohort-control study was conducted at Boonshoft School of Medicine. One hundred thirty first-year medical students were enrolled in an Anki utilization training program from July 2021 to September 2021. Training included educational Anki courses and subsequent survey data collection over Anki usage. Data variables included all course final examinations, the Comprehensive Basic Science Exam (CBSE), individual Anki user statistics, nationally standardized exams scores, and Qualtrics surveys on student perceived ease of use. Results Seventy-eight students reported using Anki for at least one of the exams, and 52 students did not use Anki for any exam. Anki users scored significantly higher across all four exams: Course I (6.4%; p \u3c 0.001); Course II (6.2%; p = 0.002); Course III (7.0%; p = 0.002); and CBSE (12.9%; p = 0.003). Students who reported higher dependency on Anki for studying performed significantly better on the Course I, II, and CBSE exams. Conclusion Anki usage may be associated with an increase in standardized examination scores. This supports Anki as an evidence-based spaced repetition and active retrieval learning modality for medical school standardized examinations. There was little correlation between its specific statistical markers and examination performance. This is pertinent to physicians and medical students alike as the learning and preservation of biomedical knowledge is required for examinations and effective clinical care

    Tbet Expression in Regulatory T Cells Is Required to Initiate Th1-Mediated Colitis

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    In normal conditions gut homeostasis is maintained by the suppressive activity of regulatory T cells (Tregs), characterized by the expression of the transcription factor FoxP3. In human inflammatory bowel disease, which is believed to be the consequence of the loss of tolerance toward antigens normally contained in the gut lumen, Tregs have been found to be increased and functionally active, thus pointing against their possible role in the pathogenesis of this immune-mediated disease. Though, in inflammatory conditions, Tregs have been shown to upregulate the T helper (Th) type 1-related transcription factor Tbet and to express the pro-inflammatory cytokine IFN\u3b3, thus suggesting that at a certain point of the inflammatory process, Tregs might contribute to inflammation rather than suppress it. Starting from the observation that Tregs isolated from the lamina propria of active but not inactive IBD patients or uninflamed controls express Tbet and IFN\u3b3, we investigated the functional role of Th1-like Tregs in the dextran sulfate model of colitis. As observed in human IBD, Th1-like Tregs were upregulated in the inflamed lamina propria of treated mice and the expression of Tbet and IFN\u3b3 in Tregs preceded the accumulation of conventional Th1 cells. By using a Treg-specific Tbet conditional knockout, we demonstrated that Tbet expression in Tregs is required for the development of colitis. Indeed, Tbet knockout mice developed milder colitis and showed an impaired Th1 immune response. In these mice not only the Tbet deficient Tregs but also the Tbet proficient conventional T cells showed reduced IFN\u3b3 expression. However, Tbet deficiency did not affect the Tregs suppressive capacity in vitro and in vivo in the adoptive transfer model of colitis. In conclusion here we show that Tbet expression by Tregs sustains the early phase of the Th1-mediated inflammatory response in the gut

    Robustness Verification of Support Vector Machines

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    We study the problem of formally verifying the robustness to adversarial examples of support vector machines (SVMs), a major machine learning model for classification and regression tasks. Following a recent stream of works on formal robustness verification of (deep) neural networks, our approach relies on a sound abstract version of a given SVM classifier to be used for checking its robustness. This methodology is parametric on a given numerical abstraction of real values and, analogously to the case of neural networks, needs neither abstract least upper bounds nor widening operators on this abstraction. The standard interval domain provides a simple instantiation of our abstraction technique, which is enhanced with the domain of reduced affine forms, which is an efficient abstraction of the zonotope abstract domain. This robustness verification technique has been fully implemented and experimentally evaluated on SVMs based on linear and nonlinear (polynomial and radial basis function) kernels, which have been trained on the popular MNIST dataset of images and on the recent and more challenging Fashion-MNIST dataset. The experimental results of our prototype SVM robustness verifier appear to be encouraging: this automated verification is fast, scalable and shows significantly high percentages of provable robustness on the test set of MNIST, in particular compared to the analogous provable robustness of neural networks
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