TMBF: Bloom filter algorithms of time-dependent multi bit-strings for incremental set

Set is widely used as a kind of basic data structure. However, when it is used for large scale data set the cost of storage, search and transport is overhead. The bloom filter uses a fixed size bit string to represent elements in a static set, which can reduce storage space and search cost that is a fixed constant. The time-space efficiency is achieved at the cost of a small probability of false positive in membership query. However, for many applications the space savings and locating time constantly outweigh this drawback. Dynamic bloom filter (DBF) can support concisely representation and approximate membership queries of dynamic set instead of static set. It has been proved that DBF not only possess the advantage of standard bloom filter, but also has better features when dealing with dynamic set. This paper proposes a time-dependent multiple bit-strings bloom filter (TMBF) which roots in the DBF and targets on dynamic incremental set. TMBF uses multiple bit-strings in time order to present a dynamic increasing set and uses backward searching to test whether an element is in a set. Based on the system logs from a real P2P file sharing system, the evaluation shows a 20% reduction in searching cost compared to DBF

Enhanced oxidation resistance of active nanostructures via dynamic size effect.

A major challenge limiting the practical applications of nanomaterials is that the activities of nanostructures (NSs) increase with reduced size, often sacrificing their stability in the chemical environment. Under oxidative conditions, NSs with smaller sizes and higher defect densities are commonly expected to oxidize more easily, since high-concentration defects can facilitate oxidation by enhancing the reactivity with O2 and providing a fast channel for oxygen incorporation. Here, using FeO NSs as an example, we show to the contrary, that reducing the size of active NSs can drastically increase their oxidation resistance. A maximum oxidation resistance is found for FeO NSs with dimensions below 3.2 nm. Rather than being determined by the structure or electronic properties of active sites, the enhanced oxidation resistance originates from the size-dependent structural dynamics of FeO NSs in O2. We find this dynamic size effect to govern the chemical properties of active NSs

Effects of flavonoids extracted from the whole plant of Patrinia Villosa (Thunb) Juss in a rat model of chronic pelvic inflammation

Purpose: To investigate the effects of total flavonoids (PLV) extracted from the  whole plant of Patrinia Villosa (Thunb.) Juss (PTJ) in a rat model of chronic pelvic inflammation.Methods: An orthogonal test design was employed to optimize the extraction  conditions of PLV via reflux extraction by ethanol. Rats were randomly divided into control group, model group and PLV groups. An absorbable gelatin sponge with  pathogens was inserted into the cervix of the rat to establish a pelvic inflammatory model. The PLV groups were orally administered PLV at doses of 25, 50 and 100 mg/kg for eight days. Enzyme-linked immunosorbent assay (ELISA) was used for the determination of inflammatory cytokines in rat serum and the culture  supernatant of RAW264.7 cells. Real-time reverse transcription polymerase chain reaction (real-time PCR) was employed to determine mRNA levels.Results: The optimum extraction conditions for PLV by orthogonal test were  obtained: extraction time (120 min), ratio of liquid to raw material (20 mL/g) and ethanol concentration (50 %). By treating with PLV, the levels of TNF-α, IL-6 and IL-1β significantly decreased (p < 0.01), while IL-10 level significantly increased (p < 0.01) in the serum of chronic pelvic inflammatory rats and LPS-stimulated  macrophages. In addition, a similar trend was observed in the mRNA levels of LPS-stimulated macrophages treated with PLV.Conclusion: PLV showes significant anti-inflammatory effects on chronic pelvic inflammation. The potential mechanism is related to regulating the expression of inflammatory factorsKeywords: Patrinia Villosa (Thunb.) Juss, Total flavonoids, Chronic pelvic  inflammation, Inflammatory cytokine

Antitumor activity of physcion 8-o-β-glucopyranoside against cervical cancer by induction of apoptosis

Purpose: To investigate the antitumor activity of physcion8-O-β-glucopyranoside (PSG) against cervical cancer, as well as its mechanisms.Methods: The anti-proliferative effects of PSG on HeLa cells were determined by CCK-8 assay and the half maximal inhibitory concentration (IC50) values were calculated. Subsequently, a mouse xenograft model of HeLa cell line was established to investigate the antitumor effect of PSG in vivo. Furthermore, cell apoptosis was investigated by fluorescence microscopy via DAPI staining, and other mechanisms were determined by Western blot assay.Results: In vitro, PSG exhibited significant anti-proliferative effect on HeLa cells (p <0.05) in concentration-and time-dependent manners, with an IC50 value of 41.34 μg/mL. In vivo, PSG also had significant anti-tumor activity in nude mouse xenograft model (p < 0.05), inhibiting tumor growth. Furthermore, the results showed that treatment with PSG (20, 40 and 60 μg/mL) for 24 h resulted in significantly  increased apoptosis in HeLa cells (p < 0.05). Additionally, Western blot analysis revealed that after exposure to 20, 40 and 60 μg/mL of PSG for 24 h, protein expressions of C-caspase-3, Ccaspase-9 and Bax were markedly up-regulated (p < 0.05) while Bcl-2 was significantly down-regulated (p < 0.05). These results confirmed that PSG inhibited HeLa cell growth by inducing mitochondriamediated apoptosis via up-regulation of caspase-3 and caspase-9 and Bax, and  down-regulation of Bcl-2.Conclusion: The results demonstrate that PSG possesses notable anti-tumor activity against cervical cancer and that the mechanisms involve induction of apoptosis by mitochondria-mediated signaling pathway.Keywords: Physcion 8-O-β-glucopyranoside, Cervical cancer, Apoptosis, HeLa cells, Caspase, Antitumour, Mouse xenograf

Gas kinematics and star formation in the filamentary molecular cloud G47.06+0.26

We performed a multi-wavelength study toward the filamentary cloud G47.06+0.26 to investigate the gas kinematics and star formation. We present the 12CO (J=1-0), 13CO (J=1-0) and C18O (J=1-0) observations of G47.06+0.26 obtained with the Purple Mountain Observation (PMO) 13.7 m radio telescope to investigate the detailed kinematics of the filament. The 12CO (J=1-0) and 13CO (J=1-0) emission of G47.06+0.26 appear to show a filamentary structure. The filament extends about 45 arcmin (58.1 pc) along the east-west direction. The mean width is about 6.8 pc, as traced by the 13CO (J=1-0) emission. G47.06+0.26 has a linear mass density of about 361.5 Msun/pc. The external pressure (due to neighboring bubbles and H II regions) may help preventing the filament from dispersing under the effects of turbulence. From the velocity-field map, we discern a velocity gradient perpendicular to G47.06+0.26. From the Bolocam Galactic Plane Survey (BGPS) catalog, we found nine BGPS sources in G47.06+0.26, that appear to these sources have sufficient mass to form massive stars. We obtained that the clump formation efficiency (CFE) is about 18% in the filament. Four infrared bubbles were found to be located in, and adjacent to, G47.06+0.26. Particularly, infrared bubble N98 shows a cometary structure. CO molecular gas adjacent to N98 also shows a very intense emission. H II regions associated with infrared bubbles can inject the energy to surrounding gas. We calculated the kinetic energy, ionization energy, and thermal energy of two H II regions in G47.06+0.26. From the GLIMPSE I catalog, we selected some Class I sources with an age of about 100000 yr, which are clustered along the filament. The feedback from the H II regions may cause the formation of a new generation of stars in filament G47.06+0.26.Comment: 10 pages, 11 figures, accepted for publication in A&

Relationship between nutrient pollutants and suspended sediments in upper reaches of Yangtze River

AbstractIn order to study the relationship between nutrient pollutants and suspended sediments (SS) in the upper reaches of the Yangtze River and two tributaries, water samples were collected from September 1, 2010 to September 30, 2011 at the Zhutuo, Cuntang, Beibei, Wulong, Qingxichang, Wanxian, and Fengjie cross-sections. In the laboratory, the SS concentration and the concentration of SS whose particle size was smaller than 0.02 mm were measured. The phosphorus (P), nitrogen (N), and permanganate index (CODMn) concentrations in the natural water sample, the settled water sample, and two types of filtered water samples obtained through filter membranes with pore sizes of 0.02 mm and 0.45 μm were monitored synchronously. The results show that there are strong relationships between the P and CODMn concentrations and the SS concentration. P mainly exists in particulate form, while N mainly exists in dissolved form. SS whose particle size is smaller than 0.02 mm accounts for a high proportion of sediments in the Yangtze River and has a strong effect on water quality. At the seven cross-sections, the amounts of P, N, and CODMn in particulate form in the wet season are higher than in the dry season and the adsorption amounts of P, N, and CODMn per unit mass of sediment are higher in the dry season than in the wet season

Magnetic surface on nonmagnetic bulk of electride Hf2S

Recent experiment reported the self-passivated electride Hf2S with excellent stability and continuous electrocatalytic ability [S. H. Kang et al., Sci. Adv. 6, eaba7416 (2020)]. Starting from its 2H-type layered structure, we have studied the electronic, magnetic, and transport properties of the electride Hf2S in the monolayer and multilayer forms by combining first-principles electronic structure calculations and Kubo formula approach. Our calculations indicate that these thin films of Hf2S electride are both dynamically and thermodynamically stable. Astonishingly, the calculations further show that the outmost Hf atoms and the surface electron gas of the Hf2S multilayers are spin polarized, while the inner Hf atoms and the electron gas in the interlayer regions remain nonmagnetic. Due to the magnetic surface, the multilayer Hf2S exhibits many unusual transport properties such as the surface anomalous Hall effect and the electric-field-induced layer Hall effect. Our theoretical predictions on Hf2S call for future experimental verification.Comment: 5 pages, 5 figures, 34 reference