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Now showing items 65 - 80 of 230

  • Targeted delivery of doxorubicin to tumour tissues by a novel legumain sensitive polygonal nanogel

    Lin, Sen   Li, Tong   Xie, Peiling   Li, Qing   Wang, Bailiang   Wang, Lei   Li, Lingli   Wang, Yuqin   Chen, Hao   Nan, Kaihui  

    Targeted delivery of cytotoxic drugs to tumour tissue has great importance for successful chemotherapy. Legumain is an asparaginyl endopeptidase that is highly up-regulated in a number of solid tumours. The aim of this work was to prepare a novel hyaluronic acid (HA) based legumain sensitive nanogel for the delivery of doxorubicin with a high targeting efficiency both in vitro and in vivo. The legumain sensitive property is achieved by the conjugation of doxorubicin with HA via a legumain substrate peptide bridge. This HA derivative is further crosslinked in a water/oil solvent system to form a polygonal nanogel. Doxorubicin released in the tumour tissue is sustained thanks to the combined action of legumain and hyaluronidase, which are both overexpressed in tumour tissues. Hyaluronic acid could act as a targeting agent to CD44 (HA receptor), which further improved the in vivo target effect and enhanced in vitro cellular uptake. The developed nanogel exhibited a high therapeutic index that improved tumour inhibition effects and reduced system toxicity in a lung cancer mice model. These results highlighted the advantages of using this multi-functional material for a successful delivery of doxorubicin against cancer.
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  • Three-component difunctionalization of alkenes leading to beta-acetamido sulfides and beta-acetoxy sulfides

    Wang, Dingyi   Yan, Zhaohua   Xie, Qihuang   Zhang, Rongxing   Lin, Sen   Wang, Yuanxing  

    A novel method for the synthesis of beta-acetamido sulfides via NBS-mediated aminosulfenylation of alkenes with thiophenols and nitriles under metal-free conditions has been described. And beta-acetamido sulfides were also synthesized with 1-(arylthio) pyrrolidine-2,5-diones as substrates and HBr as an additive. On the other hand, iodine-catalyzed1,2-acetoxysulfenylation of alkenes by using (diacetoxyiodo) benzene as an oxygen source to synthesise various beta-acetoxy sulfides was described as well.
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  • Polyinosinic-polycytidylic acid has therapeutic effects against cerebral ischemia/reperfusion injury through the downregulation of TLR4 signaling via TLR3.

    Wang, Peng-Fei   Fang, Huang   Chen, Jing   Lin, Sen   Liu, Yong   Xiong, Xiao-Yi   Wang, Yan-Chun   Xiong, Ren-Ping   Lv, Feng-Lin   Wang, Jian   Yang, Qing-Wu  

    Recent reports have shown that preconditioning with the TLR3 ligand polyinosinic-polycytidylic acid (poly(I:C)) protects against cerebral ischemia/reperfusion (I/R) injury. However, it is unclear whether poly(I:C) treatment after cerebral I/R injury is also effective. We used mouse/rat middle cerebral artery occlusion and cell oxygen-glucose deprivation models to evaluate the therapeutic effects and mechanisms of poly(I:C) treatment. Poly(I:C) was i.p. injected 3 h after ischemia (treatment group). Cerebral infarct volumes and brain edemas were significantly reduced, and neurologic scores were significantly increased. TNF-alpha and IL-1beta levels were markedly decreased, whereas IFN-beta levels were greatly increased, in the ischemic brain tissues, cerebral spinal fluid, and serum. Injuries to hippocampal neurons and mitochondria were greatly reduced. The numbers of TUNEL-positive and Fluoro-Jade B(+) cells also decreased significantly in the ischemic brain tissues. Poly(I:C) treatment increased the levels of Hsp27, Hsp70, and Bcl2 and decreased the level of Bax in the ischemic brain tissues. Moreover, poly(I:C) treatment attenuated the levels of TNF-alpha and IL-1beta in serum and cerebral spinal fluid of mice stimulated by LPS. However, the protective effects of poly(I:C) against cerebral ischemia were abolished in TLR3(-/-) and TLR4(-/-)mice. Poly(I:C) downregulated TLR4 signaling via TLR3. Poly(I:C) treatment exhibited obvious protective effects 14 d after ischemia and was also effective in the rat permanent middle cerebral artery occlusion model. The results suggest that poly(I:C) exerts therapeutic effects against cerebral I/R injury through the downregulation of TLR4 signaling via TLR3. Poly(I:C) is a promising new drug candidate for the treatment of cerebral infarcts. =20
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  • Theoretical Insight into the Reaction Mechanism of Ethanol Steam Reforming on Co(0001)

    Lin, Sen   Huang, Jing   Gao, Xiaomei   Ye, Xinxin   Guo, Hua  

    By using plane-wave density functional theory, the reaction mechanism of ethanol steam reforming (ESR) on the Co(0001) surface is investigated by systematically exploring the barriers and reaction energies of elementary steps. Our results suggest that ESR is initiated by decomposition of ethanol: CH3CH2OH* -> CH3CH2O* -> CH3CHO* -> CH3CO* -> CH3* + CO*. This is followed by the watergas shift (CO* + OH* -> COOH* -> CO2* + H*) or direct oxidation (CO* + O* -> CO2*) reaction to produce CO2. The reaction between CO* and OH*/O* is considered to be the key step in ESR. The proposed mechanism is consistent with most available experimental data and provides theoretical insight into the reaction pathways of the ESR process on cobalt catalysts.
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  • Photocatalysis: Novel Porous Boron Nitride Nanosheet with Carbon Doping: Potential Metal‐Free Photocatalyst for Visible‐Light‐Driven Overall Water Splitting (Adv. Theory Simul. 4/2019)

    Wan, Qiang   Wei, Fenfei   Ma, Zuju   Anpo, Masakazu   Lin, Sen  

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  • Calcification response of Pleurochrysis carterae to iron concentrations in batch incubations:implication for the marine biogeochemical cycle

    Zou, Xiang   Sun, Shiyong   Lin, Sen   Shen, Kexuan   Dong, Faqin   Tan, Daoyong   Nie, Xiaoqin   Liu, Mingxue   Wei, Jie  

    Calcified coccolithophores, a diverse and widely distributed group of marine microalgae, produce biogenic calcite in the form of coccoliths located on the cell surface. Using batch incubations of the coccolithophorid Pleurochrysis carterae, we investigated the responses of this calcification process to iron concentrations by changing the iron supply in the initial culture media from a normal concentration to 1 ppm (parts per million), 5 ppm, and 10 ppm. Time-dependent measurements of cell population, production of inorganic carbon (coccoliths), and organic carbon (organic cellular components) showed that elevated iron supply in the growth medium of P. carterae stimulates carbon sequestration by increasing growth along enhanced photosynthetic activity and calcification. In addition, the acquired time-dependent UV-Vis and FT-IR spectra revealed that iron fertilization-enhanced coccolith calcification is accompanied by a crystalline phase transition from calcite to aragonite or amorphous phase. Our results suggest that iron concentration has a significant influence on the marine carbon cycle of coccolithophores.
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  • On the mechanism of alkyne hydrogenation catalyzed by Ga-doped ceria

    Zhou, Shulan   Gao, Liye   Wei, Fenfei   Lin, Sen   Guo, Hua  

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  • Direct Blow Spinning of Flexible and Transparent Ag Nanofiber Heater

    Wang, Haiyang   Lin, Sen   Zu, Di   Song, Jianan   Liu, Zhenglian   Li, Lei   Jia, Chao   Bai, Xiaopeng   Liu, Junchen   Li, Ziwei   Wang, Dong   Huang, Ya   Fang, Minghao   Lei, Ming   Li, Bo   Wu, Hui  

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  • Monitoring Rice Phenology Based on Backscattering Characteristics of Multi-Temporal RADARSAT-2 Datasets

    He, Ze   Li, Shihua   Wang, Yong   Dai, Leiyu   Lin, Sen  

    Accurate estimation and monitoring of rice phenology is necessary for the management and yield prediction of rice. The radar backscattering coefficient, one of the most direct and accessible parameters has been proved to be capable of retrieving rice growth parameters. This paper aims to investigate the possibility of monitoring the rice phenology (i.e., transplanting, vegetative, reproductive, and maturity) using the backscattering coefficients or their simple combinations of multi-temporal RADARSAT-2 datasets only. Four RADARSAT-2 datasets were analyzed at 30 sample plots in Meishan City, Sichuan Province, China. By exploiting the relationships of the backscattering coefficients and their combinations versus the phenology of rice, HH/VV, VV/VH, and HH/VH ratios were found to have the greatest potential for phenology monitoring. A decision tree classifier was applied to distinguish the four phenological phases, and the classifier was effective. The validation of the classifier indicated an overall accuracy level of 86.2%. Most of the errors occurred in the vegetative and reproductive phases. The corresponding errors were 21.4% and 16.7%, respectively.
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  • Reduced graphene oxide-NiCo2O4 nanoflowers as efficient electrocatalysts for the oxygen reduction reaction

    Lin, Sen   Shi, Xiaoyu   Yang, Hujiang   Fan, Dongyu   Wang, Yonggang   Bi, Ke  

    Two-dimensional materials have already become the focus of many researches due to their innovation potential in various fields related to their special structure. Particularly, more and more two-dimensional electrocatalysts are being developed for the oxygen reduction reaction (ORR). In this work, novel two-dimensional NiCo2O4 nanoflowers/reduced graphene oxide (NCONFs/rGO) nanocomposite ORR catalysts have been successfully synthetized via a two-steps method. The micromorphology and microstructure of the obtained samples were analyzed via XRD, SEM, TEM and Raman spectroscopy. The different characterizations showed a typical petal-like structure of NiCo2O4 and a good coupling between NCONFs and rGO. Electrochemical measurements demonstrated both superior NCONFs/rGO ORR activity (0.92 V of onset potential, vs. RHE) and an excellent catalytic stability (6.4% decrease in current during a 10,000 s test). Such outstanding performances have never been reported before for ORR catalysts and originate from the two-dimensional microstructure of materials combined with the supporting rGO layer. (C) 2017 Published by Elsevier B.V.
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  • A 40-Gb/s PAM-4 Transmitter Based on a Ring-Resonator Optical DAC in 45-nm SOI CMOS

    Moazeni, Sajjad   Lin, Sen   Wade, Mark   Alloatti, Luca   Ram, Rajeev J.   Popovic, Milos   Stojanovic, Vladimir  

    The next generations of large-scale data-centers and supercomputers demand optical interconnects to migrate to 400G and beyond. Microring modulators in silicon-photonics VLSI chips are promising devices to meet this demand due to their energy efficiency and compatibility with dense wavelength division multiplexed chip-to-chip optical I/O. Higher order pulse amplitude modulation (PAM) schemes can be exploited to mitigate their fundamental energy-bandwidth tradeoff at the system level for high data rates. In this paper, we propose an optical digital-to-analog converter based on a segmented microring resonator, capable of operating at 20 GS/s with improved linearity over conventional optical multi-level generators that can be used in a variety of applications such as optical arbitrary waveform generators and PAM transmitters. Using this technique, we demonstrate a PAM-4 transmitter that directly converts the digital data into optical levels in a commercially available 45-nm SOI CMOS process. We achieved 40-Gb/s PAM-4 transmission at 42-fJ/b modulator and driver energies, and 685-fJ/b total transmitter energy efficiency with an area bandwidth density of 0.67 Tb/s/mm(2). The transmitter incorporates a thermal tuning feedback loop to address the thermal and process variations of microrings' resonance wavelength. This scheme is suitable for system-on-chip applications with a large number of I/O links, such as switches and general-purpose and specialized processors in large-scale computing and storage systems.
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  • Characterisation of the inhomogeneity of sol-gel-derived SiO(2)-CaO bioactive glass and a strategy for its improvement RID B-1007-2012

    Lin, Sen   Ionescu, Claudia   Baker, Simon   Smith, Mark E.   Jones, Julian R.  

    Sol-gel derived bioactive glasses are one of the most promising materials for bone regeneration. The nanostructure of the glasses is critical regarding their interaction with the physiological environment. Composition is one of the most important factors affecting the nanostructure. In this study, inhomogeneity (a translucent component surrounded by an opaque component) was found within sol-gel derived bioactive glass monoliths (70 mol% SiO(2) and 30 mol% CaO) produced by a standard procedure. The nanostructure and composition of the two components were characterised by electron microscopy, nitrogen sorption, secondary ion mass spectroscopy, X-ray fluorescence and solid state nuclear magnetic resonance. Results showed that calcium concentration and nanoscale porosity were much higher in the opaque region than in the translucent component. This is believed to be caused by calcium nitrate accumulation on the outer surface of the monoliths during the drying stage of the sol-gel process. The homogeneity of monoliths was successfully improved by using Teflon moulds. These findings are important for the large scale commercial production of homogeneous sol-gel glasses.
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  • Contralateral C7 transfer via the prespinal and retropharyngeal route to repair brachial plexus root avulsion: A preliminary report

    Xu, Lei   Gu, Yudong   Xu, Jianguang   Lin, Sen   Chen, Liang   Lu, Jiuzhou  

    OBJECTIVE: We sought to investigate a shorter and safer route for contralateral C7 transfer. METHODS: Eight male patients were treated from December 2005 to November 2006. Their ages ranged from 22 to 43 years (average, 30 yr). Five patients had total brachial plexus avulsion. The operative delay was from 2 to 6 months (mean, 4 mo). The bilateral scalenus anterior muscles were transected before a prespinal and retropharyngeal tunnel was made. The contralateral C7 nerve root was used to repair the upper trunk or the infraclavicular lateral cord and posterior cord of the injured side via this route, with the use of direct neurorrhaphy or nerve grafting. RESULTS: The length of the harvested contralateral C7 nerve root was 4.67 +/- 0.52 cm in the first five patients. The nerve graft was 6.25 +/- 0.35 cm long for repairing supraclavicular brachial plexus and 8.56 +/- 0.45 cm long for repairing infraclavicular brachial plexus. The length of the harvested contralateral C7 nerve root averaged 6.85 cm in the last three patients, two of whom had direct neurorrhaphy to the C5 and six residual nerve roots; in the other patient, a nerve graft 3 cm in length was used. Transient contralateral sensory symptoms were reported in most patients. In all cases, shoulder abduction and elbow flexion recovered by 12 months postoperatively. CONCLUSION: Transection of the bilateral scalenus muscles can reduce the length of the nerve graft and allow the C7 nerve to be transferred more smoothly and safely through the prespinal and retropharyngeal route; this method also favors nerve regeneration and functional recovery.
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  • Synthetic Route to Metal Nitrides:High-Pressure Solid-State Metathesis Reaction

    Lei, Li   Yin, Wenwen   Jiang, Xiaodong   Lin, Sen   He, Duanwei  

    We report a general synthetic route to well-crystallized metal nitrides through a high-pressure solid-state metathesis reaction (HPSSM) between boron nitride (BN) and ternary metal oxide A(x)M(y)O(z) (A =3D alkaline or alkaline-earth metal and M =3D main group or transition metal). On the basis of the synthetic metal nitrides (Fe3N, Re3N, VN, GaN, CrN, and WxN) and elemental products (graphite, rhenium, indium, and cobalt metals), the HPSSM reaction has been systematically investigated with regard to its general chemical equation, reaction scheme, and characteristics, and its thermodynamic considerations have been explored by density functional theory (DFT) calculations. Our results indicate that pressure plays an important role in the synthesis, which involves an ion-exchange process between boron and the metal ion, opening a new pathway for material synthesis.
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  • Rational Design of Hierarchical TiO2/Epitaxially Aligned MoS2-Carbon Coupled Interface Nanosheets Core/Shell Architecture for Ultrastable Sodium-Ion and Lithium-Sulfur Batteries

    Yang, Yong   Wang, Shitong   Lin, Sen   Li, Yutong   Zhang, Weiyu   Chao, Yuguang   Luo, Mingchuan   Xing, Yi   Wang, Kai   Yang, Chao   Zhou, Peng   Zhang, Yelong   Tang, Zilong   Guo, Shaojun  

    The development of electrode materials with superior cycling stability is currently receiving intensive research for next-generation portable electronic equipment. Herein, a novel 3D hierarchical architecture composed of TiO2/epitaxially aligned MoS2-carbon coupled interface nanosheets is reported for boosting sodium-ion storage and lithium-sulfur batteries, in which the MoS2 nanosheets are epitaxially aligned grown on the surface of carbon nanosheets through a simple calculation conversion process. The resulting hybrid demonstrates ultralong-life performance for sodium-ion storage and lithium-sulfur batteries, owing to synergistic effects among the stable TiO2 nanowires, the high-conductivity carbon nanosheets, and the vertical MoS2 nanostructure. Even at a high current density of 8 A g(-1), the capacity can be maintained at 169 mA h g(-1) after 15 000 cycles, one of the highest values for TiO2-based electrodes. Moreover, such peculiar sheet-on-sheet structure also brings benefits for lithium-sulfur batteries, providing an effective physical shield against polysulfide shuttling and chemical adsorption of polysulfides, with a low fading rate (0.039% per cycle over 1500 cycles). The present work highlights that this rationally designed hybrid nanoarchitecture is an effective strategy to boost the stability of electrochemical energy storage.
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  • Toll-like receptors in cerebral ischemic inflammatory injury

    Wang, Yan-Chun   Lin, Sen  

    Cerebral ischemia triggers acute inflammation, which has been associated with an increase in brain damage. The mechanisms that regulate the inflammatory response after cerebral ischemia are multifaceted. An important component of this response is the activation of the innate immune system. However, details of the role of the innate immune system within the complex array of mechanisms in cerebral ischemia remain unclear. There have been recent great strides in our understanding of the innate immune system, particularly in regard to the signaling mechanisms of Toll-like receptors (TLRs), whose primary role is the initial activation of immune cell responses. So far, few studies have examined the role of TLRs in cerebral ischemia. However, work with experimental models of ischemia suggests that TLRs are involved in the enhancement of cell damage following ischemia, and their absence is associated with lower infarct volumes. It may be possible that therapeutic targets could be designed to modulate activities of the innate immune system that would attenuate cerebral brain damage. Ischemic tolerance is a protective mechanism induced by a variety of preconditioning stimuli. Interpreting the molecular mechanism of ischemic tolerance will open investigative avenues into the treatment of cerebral ischemia. In this review, we discuss the critical role of TLRs in mediating cerebral ischemic injury. We also summarize evidence demonstrating that cerebral preconditioning downregulates pro-inflammatory TLR signaling, thus reducing the inflammation that exacerbates ischemic brain injury.
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