311 research outputs found
Homogenized finite element analysis on effective elastoplastic mechanical behaviors of composite with imperfect interfaces
A three-dimensional (3D) representative volume element (RVE) model was developed for analyzing effective mechanical behavior of fiber-reinforced ceramic matrix composites with imperfect interfaces. In the model, the fiber is assumed to be perfectly elastic until its tensile strength, and the ceramic material is modeled by an elasto-plastic Drucker-Prager constitutive law. The RVE model is then used to study the elastic properties and the tensile strength of composites with imperfect interfaces and validated through experiments. The imperfect interfaces between the fiber and the matrix are taken into account by introducing some cohesive contact surfaces. The influences of the interface on the elastic constants and the tensile strengths are examined through these interface models
Optimal Sample Selection Through Uncertainty Estimation and Its Application in Deep Learning
Modern deep learning heavily relies on large labeled datasets, which often
comse with high costs in terms of both manual labeling and computational
resources. To mitigate these challenges, researchers have explored the use of
informative subset selection techniques, including coreset selection and active
learning. Specifically, coreset selection involves sampling data with both
input (\bx) and output (\by), active learning focuses solely on the input
data (\bx).
In this study, we present a theoretically optimal solution for addressing
both coreset selection and active learning within the context of linear softmax
regression. Our proposed method, COPS (unCertainty based OPtimal Sub-sampling),
is designed to minimize the expected loss of a model trained on subsampled
data. Unlike existing approaches that rely on explicit calculations of the
inverse covariance matrix, which are not easily applicable to deep learning
scenarios, COPS leverages the model's logits to estimate the sampling ratio.
This sampling ratio is closely associated with model uncertainty and can be
effectively applied to deep learning tasks. Furthermore, we address the
challenge of model sensitivity to misspecification by incorporating a
down-weighting approach for low-density samples, drawing inspiration from
previous works.
To assess the effectiveness of our proposed method, we conducted extensive
empirical experiments using deep neural networks on benchmark datasets. The
results consistently showcase the superior performance of COPS compared to
baseline methods, reaffirming its efficacy
Characteristics and a comparison of the gut microbiota in two frog species at the beginning and end of hibernation
Season has been suggested to contribute to variation in the gut microbiota of animals. The complicated relationships between amphibians and their gut microbiota and how they change throughout the year require more research. Short-term and long-term hypothermic fasting of amphibians may affect gut microbiota differently; however, these changes have not been explored. In this study, the composition and characteristics of the gut microbiota of Rana amurensis and Rana dybowskii during summer, autumn (short-term fasting) and winter (long-term fasting) were studied by high-throughput Illumina sequencing. Both frog species had higher gut microbiota alpha diversity in summer than autumn and winter, but no significant variations between autumn and spring. The summer, autumn, and spring gut microbiotas of both species differed, as did the autumn and winter microbiomes. In summer, autumn and winter, the dominant phyla in the gut microbiota of both species were Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria. All animals have 10 OTUs (>90% of all 52 frogs). Both species had 23 OTUs (>90% of all 28 frogs) in winter, accounting for 47.49 ± 3.84% and 63.17 ± 3.69% of their relative abundance, respectively. PICRUSt2 analysis showed that the predominant functions of the gut microbiota in these two Rana were focused on carbohydrate metabolism, Global and overview maps, Glycan biosynthesis metabolism, membrane transport, and replication and repair, translation. The BugBase analysis estimated that among the seasons in the R. amurensis group, Facultatively_Anaerobic, Forms_Biofilms, Gram_Negative, Gram_Positive, Potentially_Pathogenic were significantly different. However, there was no difference for R. dybowskii. The research will reveal how the gut microbiota of amphibians adapts to environmental changes during hibernation, aid in the conservation of endangered amphibians, particularly those that hibernate, and advance microbiota research by elucidating the role of microbiota under various physiological states and environmental conditions
The Study of Microwave and Electric Hybrid Sintering Process of AZO Target
We simulated the microwave sintering of ZnO by 3D modelling. A large-size Al-doped ZnO (AZO) green ceramic compact was prepared by slurry casting. Through studying the microwave and electric hybrid sintering of the green compact, a relative density of up to 98.1% could be obtained by starting microwave heating at 1200°C and increasing the power 20 min later to 4 kW for an AZO ceramic target measuring 120 × 240 × 12 mm. The resistivity of AZO targets sintered with microwave assistance was investigated. The energy consumption of sintering could be greatly reduced by this heating method. Until now, few studies have been reported on the microwave and electric hybrid sintering of large-size AZO ceramic targets. This research can aid in developing sintering technology for large-size high-quality oxide ceramic targets
Backreaction in Axion Monodromy, 4-forms and the Swampland
Axion monodromy models can always be described in terms of an axion coupled
to 3-form gauge fields with non-canonical kinetic terms. The presence of the
saxions parametrising the kinetic metrics of the 3-form fields leads to
backreaction effects in the inflationary dynamics. We review the case in which
saxions backreact on the K\"ahler metric of the inflaton leading to a
logarithmic scaling of the proper field distance at large field. This behaviour
is universal in Type II string flux compactifications and consistent with a
refinement of the Swampland Conjecture. The critical point at which this
behaviour appears depends on the mass hierarchy between the inflaton and the
saxions. However, in tractable compactifications, such a hierarchy cannot be
realised without leaving the regime of validity of the effective theory,
disfavouring transplanckian excursions in string theory.Comment: Proceedings prepared for the "Workshop on Geometry and Physics",
November 2016, Ringberg Castl
Loop-mediated isothermal amplification (LAMP): Early detection of Toxoplasma gondii infection in mice
<p>Abstract</p> <p>Background</p> <p>Toxoplasmosis is a widespread zoonotic parasitic disease that occurs in both animals and humans. Traditional molecular assays are often difficult to perform, especially for the early diagnosis of <it>Toxoplasma gondii </it>infections. Here, we established a novel loop-mediated isothermal amplification targeting the 529 bp repeat element (<it>529 bp</it>-LAMP) to detect <it>T. gondii </it>DNA in blood samples of experimental mice infected with tachyzoites of the RH strain.</p> <p>Findings</p> <p>The assay was performed with Bst DNA polymerase at 65°C for 1 h. The detection limit of the <it>529 bp-</it>LAMP assay was as low as 0.6 fg of <it>T. gondii </it>DNA. The sensitivity of this assay was 100 and 1000 fold higher than that of the LAMP targeting <it>B1 </it>gene (<it>B1</it>-LAMP) and nested PCR targeting 529 bp repeat element (<it>529 bp</it>-nested PCR), respectively. The specificity of the <it>529 bp-</it>LAMP assay was determined using the DNA samples of <it>Trypanosoma evansi, Plasmodium falciparum, Paragonimus westermani, Schistosoma japonicum, Fasciola hepatica </it>and <it>Angiostrongylus cantonensis</it>. No cross-reactivity with the DNA of any parasites was found. The assay was able to detect <it>T. gondii </it>DNA in all mouse blood samples at one day post infection (dpi).</p> <p>Conclusions</p> <p>We report the following findings: (<it>i</it>) The detection limit of the <it>529 bp-</it>LAMP assay is 0.6 fg of <it>T. gondii </it>DNA; (<it>ii</it>) The assay does not involve any cross-reactivity with the DNA of other parasites; (<it>iii</it>) This is the first report on the application of the LAMP assay for early diagnosis of toxoplasmosis in blood samples from experimentally infected mice. Due to its simplicity, sensitivity and cost-effectiveness for common use, we suggest that this assay should be used as an early diagnostic tool for health control of toxoplasmosis.</p
The LAMOST Survey of Background Quasars in the Vicinity of the Andromeda and Triangulum Galaxies -- II. Results from the Commissioning Observations and the Pilot Surveys
We present new quasars discovered in the vicinity of the Andromeda and
Triangulum galaxies with the LAMOST during the 2010 and 2011 observational
seasons. Quasar candidates are selected based on the available SDSS, KPNO 4 m
telescope, XSTPS optical, and WISE near infrared photometric data. We present
509 new quasars discovered in a stripe of ~135 sq. deg from M31 to M33 along
the Giant Stellar Stream in the 2011 pilot survey datasets, and also 17 new
quasars discovered in an area of ~100 sq. deg that covers the central region
and the southeastern halo of M31 in the 2010 commissioning datasets. These 526
new quasars have i magnitudes ranging from 15.5 to 20.0, redshifts from 0.1 to
3.2. They represent a significant increase of the number of identified quasars
in the vicinity of M31 and M33. There are now 26, 62 and 139 known quasars in
this region of the sky with i magnitudes brighter than 17.0, 17.5 and 18.0
respectively, of which 5, 20 and 75 are newly-discovered. These bright quasars
provide an invaluable collection with which to probe the kinematics and
chemistry of the ISM/IGM in the Local Group of galaxies. A total of 93 quasars
are now known with locations within 2.5 deg of M31, of which 73 are newly
discovered. Tens of quasars are now known to be located behind the Giant
Stellar Stream, and hundreds behind the extended halo and its associated
substructures of M31. The much enlarged sample of known quasars in the vicinity
of M31 and M33 can potentially be utilized to construct a perfect astrometric
reference frame to measure the minute PMs of M31 and M33, along with the PMs of
substructures associated with the Local Group of galaxies. Those PMs are some
of the most fundamental properties of the Local Group.Comment: 26 pages, 6 figures, AJ accepte
Salaklar Derneği, Sözen'i yılın adamı seçti
Taha Toros Arşivi, Dosya No: 207-Nurettin-Gürol-Metin SözenUnutma İstanbul projesi İstanbul Kalkınma Ajansı'nın 2016 yılı "Yenilikçi ve Yaratıcı İstanbul Mali Destek Programı" kapsamında desteklenmiştir. Proje No: TR10/16/YNY/010
21-Gene Recurrence Score Assay Could Not Predict Benefit of Post-mastectomy Radiotherapy in T1-2 N1mic ER-Positive HER2-Negative Breast Cancer
Introduction: It is still controversial whether post-mastectomy radiotherapy (PMRT) is necessary for women with T1-2 N1mic ER-positive HER2-negative breast cancer. The 21-gene recurrence score (RS) assay has been validated in T1-2 N1 breast cancer to be prognostic of locoregional recurrence (LRR) and overall survival (OS). This study aims to evaluate the predict value of 21-gene recurrence score assay for the benefit of PMRT in T1-2 N1mic ER-positive HER2-negative breast cancer.Methods: A population-based cohort study was performed on women with T1-2 N1mic ER-positive HER2-negative breast cancer who underwent mastectomy and were evaluated using the 21-gene RS in the Surveillance, Epidemiology, and End Results (SEER) registry between 2004 and 2015. Clinical characteristics as well as OS and breast cancer-specific survival (BCSS) were compared between patients with and without PMRT in patients with a Low-, Intermediate-, and High-RS. Multivariate COX regression analysis was performed to investigate if the 21-gene RS assay could predict benefit of PMRT in this group of breast cancer patients.Results: A total of 1571 patients met the criteria of our study and were enrolled, including 970 patients in the Low-Risk group (score <18), 508 in the Intermediate-Risk group (score 18–30), and 93 patients in the High-Risk group (score >30). In the High-Risk group, there were more patients with age ≥50 (87.0 vs. 64.3%, P = 0.040) and received chemotherapy with a borderline significance (91.3 vs. 72.9%, P = 0.066) in the PMRT subgroup than in the no PMRT subgroup. In all three groups, OS was comparable between the PMRT subgroup and the no PMRT subgroup. Furthermore, multivariate analysis did not show any OS benefit for PMRT based on the 21-gene recurrence score.Conclusion: This study showed that the 21-gene RS assay was not able to predict the benefit of PMRT for OS in women with T1-2 N1mic ER-positive HER2-negative breast cancer. However, further prospective larger sample-size trials are warranted to determine if a benefit exists
BMI-1 Autoantibody as a New Potential Biomarker for Cervical Carcinoma
BMI-1 is overexpressed in a variety of cancers, which can elicit an immune response leading to the induction of autoantibodies. However, BMI-1 autoantibody as a biomarker has seldom been studied with the exception of nasopharyngeal carcinoma. Whether BMI-1 autoantibodies can be used as a biomarker for cervical carcinoma is unclear. In this study,BMI-1 proteins were isolated by screening of a T7 phage cDNA library from mixed cervical carcinoma tissues. We analyzed BMI-1 autoantibody levels in serum samples from 67 patients with cervical carcinoma and 65 controls using ELISA and immunoblot. BMI-1 mRNA or protein levels were over-expressed in cervical carcinoma cell lines. Immunoblot results exhibited increased BMI-1 autoantibody levels in patient sera compared to normal sera. Additionally, the results for antibody affinity assay showed that there was no difference between cervical polyps and normal sera of BMI-1 autoantibody levels, but it was significantly greater in patient sera than that in normal controls (patient 0.827±0.043 and normal 0.445±0.023; P<0.001). What's more, the levels of BMI-1 autoantibody increased significantly at stage I (0.672±0.019) compared to normal sera (P<0.001), and levels of BMI-1 autoantibodies were increased gradually during the tumor progression (stage I 0.672±0.019; stage II 0.775 ±0.019; stage III 0.890 ±0.027; stage IV 1.043±0.041), which were significantly correlated with disease progression of cervical carcer (P<0.001). Statistical analyses using logistic regression and receiver operating characteristics (ROC) curves indicated that the BMI-1 autoantibody level can be used as a biomarker for cervical carcinoma (sensitivity 0.78 and specificity 0.76; AUC = 0.922). In conclusion, measuring BMI-1 autoantibody levels of patients with cervical cancer could have clinical prognostic value as well as a non-tissue specific biomarker for neoplasms expressing BMI-1
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