Wyniki wyszukiwania - Biblioteka Nauki

1

Spatial distribution, environmental risk and source of heavy metals in street dust from an industrial city in semi-arid area of China

100%

Han X. , Lu X.

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2017

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tom Vol. 43, no. 2

10--19

EN

Environmental risks associated with Co, Cr, Cu, Mn, Ni, Pb, V and Zn in street dust collected from Baotou, a medium-sized industrial city in a semi-arid area of northwest China, were assessed by using enrichment factor and the potential ecological index. Their spatial distributions and sources in the dust were analyzed on the basis of geostatistical methods and multivariate statistical analysis, respectively. The results indicate that street dust in Baotou has elevated heavy metal concentrations, especially of Co, Cr, Cu, Pb and Zn. Co in the dust was significantly enriched. Cr and Pb were from moderate to significant enrichment. Cu and Zn were from minimal to moderate enrichment, whereas Mn, Ni and V in the dust were from deficient to minimal enrichment. The ecological risk levels of Co and Pb in the dust were moderate to considerable and low to moderate, respectively, whereas those of other heavy metals studied in the dust presented low ecological risk. Different distribution patterns were found among the analyzed heavy metals. Three main sources of these heavy metals were identified. Cr, Mn, Ni and V originated from nature and industrial activities. Cu, Pb and Zn derived mainly from traffic sources, and Co was mainly from construction sources.

2

Quantitative determination of glycerol in antarctic krill (Euphausia superba Dana) by high-performance thin-layer chromatography

100%

Han X. , Liu D.

Acta Chromatographica

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2018

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tom Vol. 30, no. 4

274--277

EN

In this reported study, a direct high-performance thin-layer chromatographic (HPTLC) method was developed to qualitatively detect and quantitatively determine glycerol in Antarctic krill for the first time. This procedure was based on the extraction of glycerol by ultrasonic solvent extraction with anhydrous ethanol, silica-gel column chromatographic separation, HPTLC detection and quantification using methylene chloride–methanol (5:1, v/v) as the developing solvent and alkaline potassium permanganate as chromogenic agent. The content of glycerol was 1.3725 ± 0.218 mg/g in freeze-dried Antarctic krill. The structure of glycerol in the Antarctic krill was subsequently determined by gas chromatography–mass spectrometry (GC–MS) which verified the presence of the material in the krill. The HPTLC method exhibited excellent accuracy with a recovery of 90.1–103.3% and good precision with a relative standard deviation (RSD) of 1.59–4.84%. The results clearly exhibited the applicability of the proposed for quantifying glycerol in Antarctic krill.

3

Electrospinning synthesis of hydroxyapatite nanofibers assembled from nanorods and their adsorption for heavy metal ions

80%

Zhou Y. , Li S. , Wang D. , Han X.

Polish Journal of Environmental Studies

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2019

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tom 28

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nr 2

EN

In this work, porous HAP nanofibers assembled from nanorods were developed as potential devices for the treatment of Cu(II), Cd(II), and Pb(II) contamination of consumable waters. Two steps were employed in the HAP nanofibers fabrication. First, rod-like HAP nanoparticles were synthesized through a chemical pathway from Ca(NO₃)₂ ·4H₂O, (NH₄)₂ HPO₄, and polyvinylpyrrolidone (PVP) as a capping agent. The subsequent electrospinning was performed to fabricate the PVP/HAP hybrid nanofibers as precursors to obtain pure HAP nanofibers assembled from nanorods via a calcination process. The effects of PVP dosage on morphology was investigated. And a possible formation mechanism of rod-like HAP was proposed. Then the removal efficiency of porous HAP nanofibers toward Cu(II), Cd(II), and Pb(II) were evaluated via sorption kinetics and sorption isotherms. Our results proved that the sorption kinetic data were well fitted by the pseudo second-order rate equation, and the adsorption of Cu²⁺, Cd², and Pb²⁺ ions on HAP nanofibers correlated well with the Langmuir equation as compared to Freundlich isotherm equation under the concentration range studied. These novel porous HAP nanofibers assembled from nanorods promise a feasible advance in the development of new, easy to handle, and low-cost water purifying methods.

4

Study on the optimization and performance of TDMA allocation algorithm in ships’ ad hoc networks

80%

Han X. , Li Y. , Liu G.

Polish Maritime Research

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2018

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tom 25

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nr Special Issue S2

EN

This paper analyzes the requirements of the information transmission network of ship integrated condition monitoring system, and proposes a design scheme of ship condition monitoring system based on wireless ad hoc network. The wireless ad hoc network protocol was designed, its networking process was analyzed in detail, and the network transmission performance of the monitoring system was tested. The results proved the feasibility of the system. The above solution can be used for the transmission of ship state information that satisfies the requirements of wireless transmission, and has important theoretical and practical significance. The slot allocation algorithm has been receiving extensive attention as an important part of the TDMA system research. This paper analyzes the summarization and summarization of TDMA time slot assignment algorithms from several aspects such as slot synchronization, existing slot allocation algorithm, and slot assignment model, laying an important foundation for researchers to do further research. In the TDMA system, time is divided into non-overlapping time frames, and the time frames are divided into non-overlapping time slots. Each node in the network performs corresponding operations in each time slot

5

How 23-year continuous soybean cultivation led to more SOC and thermal energy stored in Mollisol micro-aggregates

70%

Qiao Y. , Miao S. , Yue S. , Wu H. , Han X.

Polish Journal of Environmental Studies

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2016

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tom 25

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nr 3

EN

Aggregate has been recognized as a key element in the stabilization of soil organic carbon (SOC). Several researchers have done outstanding work on identifying and isolating aggregates and their physiochemical properties. However, thermal stability of SOC in soil aggregates has not yet been adequately explored. The main objective of the study was to clarify the protection of aggregation on SOC from thermal characters, and provide evidence on whether thermal analysis could be a potential rapid method to determine SOC stability in aggregates. We separated 20-cm surface soil into six fractions (>2, 1-2, 0.5-1, 0.25-0.5, 0.053-0.25 and <0.053mm) before and after 23-yr continuous soybean cultivation. The study measured the change of SOC and its thermal characteristics across aggregates using thermogravimetry-differential scanning calorimetry (TG-DSC), which also showed that the thermal stability mechanism of SOC is protected by aggregates. Results showed that 23-yr continuous soybean cultivation led to an SOC increase in 0.053-0.5 mm size aggregates, but a decrease in other large-size aggregates. Energy density in the > 0.5 mm fraction was decreased by 23-yr continuous soybean cultivation, but increased to < 0.5 mm size fraction. The largest energy density was in < 0.053 mm size fractions. In conclusion, long-term continuous soybean cultivation led to more energy transferred to micro-aggregates associated with the protection of micro-aggregates on soil SOC.

6

Permeability of P and K-nutrient through polystyrene membrane from aqueous solutions of urea + KH2PO4

70%

Deng X. , Liu K. , Han X. , Hu X. , Zheng S.

Polish Journal of Chemical Technology

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2018

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tom Vol. 20, nr 4

113--122

EN

With the polymer-coated fertilizer as background, the permeability of P- and K-nutrient through a representative polymer membrane-polystyrene membrane were investigated by measuring their permeability in the solutions of KH2 PO4 -water and urea-KH2 PO4 water at nominal temperature of 298 K using the Ussing chamber method. To analyze and interpret the variation of permeability with solute concentration, the solubility of permeate in polymer membrane were determined experimentally and the permeate diffusion coefficient were assessed by the measurements of density and apparent molar volume of the aqueous fertilizer solutions. An interesting “increase-decrease” trend for the permeability of both phosphorous (P)-nutrient, and potassium (K)-nutrient fertilizer with permeate concentration was observed, in which the increases in permeability at low concentrations of permeate could be attributed to the increase in solubility of KH2 PO4 in polymer while the decreases in permeability at high concentrations was due to the decrease in diffusion coefficient of permeate in polymer membrane. Finally, the release kinetics of these nutrients from a PS-coated urea-KH2 PO4 compound fertilizer granule was predicted using the Shaviv’s model along with the permeability data of P- and K-nutrient generated.

7

Effects of dietary vitamin E and organic selenium supplementation on the oxidative stability of lamb meat

70%

Han X. , Li J. G. , Gao Y. X. , Li Q. F. , Cao Y. F.

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nr 2

8

Interaction of abscisic acid and auxin on gene expression involved in banana ripening

61%

Lu W. , Mao L. , Chen J. , Han X. , Ren X. , Ying T. , Luo Z.

Acta Physiologiae Plantarum

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2018

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tom 40

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nr 03

9

Early pregnancy affects the expression of toll-like receptor pathway in ovine thymus

61%

Li N. , Wang L. , Cao N. , Zhang L. , Han X. , Yang L.

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tom 20

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nr 4

10

Mechanical properties and abrasive wear behaviors of in situ nano-TiCx/Al–Zn–Mg–Cu composites fabricated by combustion synthesis and hot press consolidation

51%

Gao Y. Y. , Qiu F. , Shu S. L. , Wang L. , Chang F. , Hu W. , Han X. , Li Q. , Jiang Q. C.

Archives of Civil and Mechanical Engineering

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2018

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tom Vol. 18, no. 1

179--187

EN

The in situ nano-TiCx/Al–Zn–Mg–Cu composites with different TiCx content (20, 25 and 30 vol.%) were successfully fabricated by combustion synthesis and hot press consolidation in Al–Ti–C/CNTs systems. The compressive properties and abrasive wear resistance of the composites improved with the increase in the TiCx content. The transformation of carbon source from pure C black to the mixture of C black and CNTs to pure CNTs in Al–Ti–C/CNTs systems leaded to a significant improvement in the compressive properties and wear resistance of the composites as well as a significant decrease in the average size of TiCx particles. The average size of the nano-TiCx particles in 30 vol.% TiCx/Al–Zn–Mg–Cu composite synthesized by the carbon source of CNTs reached 81 nm, moreover, the yield strength (σ0.2), the ultimate compression strength (σUCS) and the fracture strain (ɛf) of the composite reached 597 MPa, 882 MPa and 21.7%, respectively.

11

Systematic analysis of genes involved in oral cancer metastasis to lymph nodes

51%

Zhang X. , Zhang T. , Tang X. , Lin Y. , Han X. , Wang H. , Ming H. , Liu K. , Feng G.

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tom 23

EN

Oral cancer remains a deadly disease worldwide. Lymph node metastasis and invasion is one of the causes of death from oral cancer. Elucidating the mechanism of oral cancer lymph node metastasis and identifying critical regulatory genes are important for the treatment of this disease. This study aimed to identify differentially expressed genes (gene signature) and pathways that contribute to oral cancer metastasis to lymph nodes. The GSE70604-associated study compared gene profiles in lymph nodes with metastasis of oral cancer to those of normal lymph nodes. The GSE2280-associated study compared gene profiles in primary tumor of oral cancer with lymph node metastasis to those in tumors without lymph node metastasis. There are 28 common differentially expressed genes (DEGs) showing consistent changes in both datasets in overlapping analysis. GO biological process and KEGG pathway analysis of these 28 DEGs identified the gene signature CCND1, JUN and SPP1, which are categorized as key regulatory genes involved in the focal adhesion pathway. Silencing expression of CCND1, JUN and SPP1 in the human oral cancer cell line OECM-1 confirmed that those genes play essential roles in oral cancer cell invasion. Analysis of clinical samples of oral cancer found a strong correlation of these genes with short survival, especially JUN expression associated with metastasis. Our study identified a unique gene signature – CCND1, JUN and SPP1 – which may be involved in oral cancer lymph node metastasis.

12

Acidification induces Bax translocation to the mitochondria and promotes ultraviolet light-induced apoptosis

51%

Yang L. , Mei Y. , Xie Q. , Han X. , Zhang F. , Gu L. , Zhang Y. , Chen Y. , Li G. , Gao Z.

Cellular and Molecular Biology Letters

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2008

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tom 13

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nr 1

119-129

EN

It has been suggested that Bax translocation to the mitochondria is related to apoptosis, and that cytosol acidification contributes to apoptosis events. However, the mechanisms remain obscure. We investigated the effect of acidification on Bax translocation and on ultraviolet (UV) light-induced apoptosis. The Bax translocation assay in vitro showed that Bax translocated to the mitochondria at pH 6.5, whereas no Bax translocation was observed at pH 7.4. VHDBB cells expressing the GFP-Bax fusion protein were treated for 12 h with a pH 6.5 DMEM medium, nigericin (5 μg/ml) and UV light (50 J/cm2), separately or in combination, and Bax translocation to the mitochondria was determined by SDS-PAGE and Western blot, and apoptotic cell death was detected by flow cytometry. The results showed that some of the Bax translocated to the mitochondria in the cells treated with the normal medium, nigericin and UV in combination, whereas all of the Bax translocated to the mitochondria in the cells treated with the pH 6.5 medium, nigericin and UV in combination. In VHDBB cells treated for 12 h with nigericin, UV alone, and UV and nigericin in combination, the respective rates of apoptotic cell death were 25.08%, 33.25% and 52.88%. In cells treated with pH 6.5 medium and nigericin, pH 6.5 medium and UV, and pH 6.5 medium, nigericin and UV in combination, the respective rates of apoptotic cell death increased to 37.19%, 41.42% and 89.44%. Our results indicated that acidification induces Bax translocation from the cytosol to the mitochondria, and promotes UV lightmediated apoptosis. This suggests that there is a possibility of improving cancer treatment by combining acidification with irradiation or chemotherapeutic drugs.