246 research outputs found
SSBM: A Signed Stochastic Block Model for Multiple Structure Discovery in Large-Scale Exploratory Signed Networks
Signed network structure discovery has received extensive attention and has
become a research focus in the field of network science. However, most of the
existing studies are focused on the networks with a single structure, e.g.,
community or bipartite, while ignoring multiple structures, e.g., the
coexistence of community and bipartite structures. Furthermore, existing
studies were faced with challenge regarding large-scale signed networks due to
their high time complexity, especially when determining the number of clusters
in the observed network without any prior knowledge. In view of this, we
propose a mathematically principled method for signed network multiple
structure discovery named the Signed Stochastic Block Model (SSBM). The SSBM
can capture the multiple structures contained in signed networks, e.g.,
community, bipartite, and coexistence of them, by adopting a probabilistic
model. Moreover, by integrating the minimum message length (MML) criterion and
component-wise EM (CEM) algorithm, a scalable learning algorithm that has the
ability of model selection is proposed to handle large-scale signed networks.
By comparing state-of-the-art methods on synthetic and real-world signed
networks, extensive experimental results demonstrate the effectiveness and
efficiency of SSBM in discovering large-scale exploratory signed networks with
multiple structures
Flow induced dissolution of femtoliter surface droplet arrays
The dissolution of liquid nanodroplets is a crucial step in many applied
processes, such as separation and dispersion in food industry, crystal
formation of pharmaceutical products, concentrating and analysis in medical
diagnosis, and drug delivery in aerosols. In this work, using both experiments
and numerical simulations, we \textit{quantitatively} study the dissolution
dynamics of femtoliter surface droplets in a highly ordered array under a
uniform flow. Our results show that the dissolution of femoliter droplets
strongly depends on their spatial positions relative to the flow direction,
drop-to-drop spacing in the array, and the imposed flow rate. In some
particular case, the droplet at the edge of the array can dissolve about 30%
faster than the ones located near the centre. The dissolution rate of the
droplet increases by 60% as the inter-droplet spacing is increased from 2.5
m to 20 m. Moreover, the droplets close to the front of flow commence
to shrink earlier than those droplets in the center of the array. The average
dissolution rate is faster for faster flow. As a result, the dissolution time
decreases with the Reynolds number Re of the flow as . The experimental results are in good agreement with numerical
simulations where the advection-diffusion equation for the concentration field
is solved and the concentration gradient on the surface of the drop is
computed. The findings suggest potential approaches to manipulate nanodroplet
sizes in droplet arrays simply by dissolution controlled by an external flow.
The obtained droplets with varying curvatures may serve as templates for
generating multifocal microlens in one array
Sulfotanshinone Sodium Injection for Unstable Angina Pectoris: A Systematic Review of Randomized Controlled Trials
Objective. To assess the effect of sulfotanshinone sodium injection for unstable angina. Methods. We searched for published and unpublished studies up to June 2011. We included randomized controlled trials that confoundedly addressed the effect of sulfotanshinone sodium injection in the treatment of unstable angina. Results. Twenty-five studies involving 2,377 people were included. There was no evidence that sulfotanshinone sodium alone had better or worse effects to routine western medicine treatments in improving clinical symptoms (RR 1.00, 95% CI 0.90 to 1.11) and ECG (RR 0.97, 95% CI 0.87 to 1.09). However, there was evidence that sulfotanshinone sodium combined with western medications was a better treatment option than western medications alone in improving clinical symptoms (RR 1.28, 95% CI 1.23 to 1.3), ECG (RR 1.26, 95% CI 1.18 to 1.35), C-reaction protein (mean difference 2.10, 95% CI 1.63 to 2.58), and IL-6 (mean difference −3.85, 95% CI −4.10 to −3.60). There was no difference between sulfotanshinone sodium plus western medications and western medications alone affecting mortality (RR 0.50, 95% CI 0.02 to 12.13). Conclusion. Compared with western medications alone, sulfotanshinone sodium combined with western medications may provide more benefits for patients with unstable angina. Further large-scale high-quality trials are warranted
Oiling-out Crystallization of Beta-Alanine onSolid Surfaces Controlled by Solvent Exchange
Droplet formation in oiling-out crystallization has important implication for
separation and purification of pharmaceutical active ingredients by using an
antisolvent. In this work, we report the crystallization processes of
oiling-out droplets on surfaces during solvent exchange. Our model ternary
solution is beta-alanine dissolved in isopropanol and water mixture. As the
antisolvent isopropanol displaced the alanine solution pre-filled in a
microchamber, liquid-liquid phase separation occurred at the mixing front. The
alanine-rich subphase formed surface microdroplets that subsequently
crystallized with progression of solvent exchange. We find that the flow rates
have significant influence on the droplet size, crystallization process, and
growth rate, and final morphology of the crystals. At fast flow rates the
droplets solidified rapidly and formed spherical-cap structures resembling the
shape of droplets, in contrast to crystal microdomains or thin films formed at
slow flow rates. On a highly hydrophilic surface, the crystals formed thin film
without droplets formed on the surface. We further demonstrated that by the
solvent exchange crystals can be formed by using a stock solution with a very
low concentration of the precursor, and the as-prepared crystals can be used as
seeds to trigger crystallization in bulk solution. Our results suggest that the
solvent exchange has the potential to be an effective approach for controlling
oiling-out crystallization, which can be applied in wide areas, such as
separation and purification of many food, medical, and therapeutic ingredients.Comment: Advanced Materials Interfaces (2020
Comparison of three magnetization transfer ratio parameters for assessment of intestinal fibrosis in patients with Crohn’s disease
Identification of the chemical components of ethanol extract of Chenopodium ambrosioides and evaluation of their in vitro antioxidant and anti tumor activities
Purpose: To determine the characteristic chemical components of the ethanol extract of Chenopodium ambrosioides and evaluate their antioxidant and anti-tumor effects in vitro.
Methods: The plant powder (5 g) was extracted with 1 L of 80 % ethanol at room temperature for 45 min, and then placed at 60 oC at varying microwave power and duration to obtain optimal extraction conditions. Characteristic chemical components were detected using ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS/MS). Kaempferitrin was isolated from the 80 % ethanol extract using a D101 macroporous resin column, and its content was assessed by high performance liquid chromatography (HPLC). The antioxidant effect of kaempferitrin was evaluated by its ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radicals, while its anti-proliferation activity in human liver cancer cells SMMC-7721 was determined using cell counting kit-8 (CCK-8) reagent.
Results: Three characteristic components of ethanol extract of C. ambrosioides were obtained, namely, kaempferitrin, kaempferol-3-O-apigenin-7-O-rhamnoside and kaempferol-3-O-acetylapigenin-7-O-rhamnoside. Kaempferitrin was shown to possess strong DPPH radical and moderate ABTS radical scavenging activities. Kaempferitrin significantly inhibited the proliferation of SMMC-7721 cells at doses of 4 and 8 μg/mL, with half-maximal concentration (IC50) of 0.38 μM (p < 0.05).
Conclusion: Kaempferitrin extracted from C. ambrosioides has antioxidant and anti-tumor activities. The results reported here indicate that C. ambrosioides may have potential use in herbal medicine practice
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Downregulating Notch counteracts KrasG12D-induced ERK activation and oxidative phosphorylation in myeloproliferative neoplasm.
The Notch signaling pathway contributes to the pathogenesis of a wide spectrum of human cancers, including hematopoietic malignancies. Its functions are highly dependent on the specific cellular context. Gain-of-function NOTCH1 mutations are prevalent in human T-cell leukemia, while loss of Notch signaling is reported in myeloid leukemias. Here, we report a novel oncogenic function of Notch signaling in oncogenic Kras-induced myeloproliferative neoplasm (MPN). We find that downregulation of Notch signaling in hematopoietic cells via DNMAML expression or Pofut1 deletion significantly blocks MPN development in KrasG12D mice in a cell-autonomous manner. Further mechanistic studies indicate that inhibition of Notch signaling upregulates Dusp1, a dual phosphatase that inactivates p-ERK, and downregulates cytokine-evoked ERK activation in KrasG12D cells. Moreover, mitochondrial metabolism is greatly enhanced in KrasG12D cells but significantly reprogrammed by DNMAML close to that in control cells. Consequently, cell proliferation and expanded myeloid compartment in KrasG12D mice are significantly reduced. Consistent with these findings, combined inhibition of the MEK/ERK pathway and mitochondrial oxidative phosphorylation effectively inhibited the growth of human and mouse leukemia cells in vitro. Our study provides a strong rational to target both ERK signaling and aberrant metabolism in oncogenic Ras-driven myeloid leukemia
Habitat Use and Activity Patterns of Mammals and Birds in Relation to Temperature and Vegetation Cover in the Alpine Ecosystem of Southwestern China with Camera-Trapping Monitoring
The high-altitude ecosystem of the Tibetan Plateau in China is a biodiversity hotspot that provides unique habitats for endemic and relict species along an altitudinal gradient at the eastern edge. Acquiring biodiversity information in this area, where the average altitude is over 4000 m, has been difficult but has been aided by recent developments in non-invasive technology, including infrared-triggered camera trapping. We used camera trapping to acquire a substantial number of photographic wildlife records in Wolong National Nature Reserve, Sichuan, China, from 2013 to 2016. We collected information of the habitat surrounding the observation sites, resulting in a dataset covering 37 species and 12 environmental factors. We performed a multivariate statistical analysis to discern the dominant environmental factors and cluster the mammals and birds of the ecosystem in order to examine environmental factors contributing to the species’ relative abundance. Species were generalized into three main types, i.e., cold-resistant, phyllophilic, and thermophilic, according to the identified key environmental drivers (i.e., temperature and vegetation) for their abundances. The mammal species with the highest relative abundance were bharal (Pseudois nayaur), Moupin pika (Ochotona thibetana), and Himalayan marmot (Marmota himalayana). The bird species with highest relative abundance were snow partridge (Lerwa lerwa), plain mountain finch (Leucosticte nemoricola), Chinese monal (Lophophorus lhuysii), and alpine accentor (Prunella collaris)
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