Well-dispersed ultrafine nitrogen-doped TiO_2 with polyvinylpyrrolidone(PVP) acted as N-source and stabilizer for water splitting

In this paper, ultrafine nitrogen-doped TiO2 photocatalyst with enhanced photocatalytic water-splitting properties was successfully fabricated via a solvothermal method. Herein, polyvinylpyrrolidone（PVP） was used as both nitrogen source and stabilizer. The enhancement in water-splitting process can be attributed to the doping of element nitrogen, which could supply an intermediate energy level and promote the separation of photo-excited holes and electrons. Moreover, this paper provides a new application of high-molecular polymer to synthesize solar-driven water-splitting photocatalysts.

Michael Acceptor Pyrrolidone Derivatives and Their Activity against Diffuse Large B-cell Lymphoma

Objective This study aimed to design and evaluate the efficacy of pyrrolidone derivatives as potential therapeutic agents against diffuse large B-cell lymphoma(DLBCL),a common and heterogeneous malignancy of the adult lymphohematopoietic system.Given the limitations of current therapies,there is a pressing need to develop new and effective drugs for DLBCL treatment.Methods A series of pyrrolidone derivatives were synthesized,and their antitumor activities were assessed,particularly against DLBCL cell lines.Structure-activity relationship(SAR)analysis was conducted to identify key structural components essential for activity.The most promising compound,referred to as compound 7,was selected for further mechanistic studies.The expression levels of relevant mRNA and protein were detected by RT-qPCR and Western blotting,and the expression of mitochondrial membrane potential and ROS was detected using flow cytometry for further assessment of cell cycle arrest and apoptosis.Results The compound 7 exhibited good antitumor activity among the synthesized derivatives,specifically in DLBCL cell lines.SAR analysis highlighted the critical role ofα,β-unsaturated ketones in the antitumor efficacy of these compounds.Mechanistically,compound 7 was found to induce significant DNA damage,trigger an inflammatory response,cause mitochondrial dysfunction,and disrupt cell cycle progression,ultimately leading to apoptosis of DLBCL cells.Conclusion The compound 7 has good antitumor activity and can induce multiple cellular mechanisms leading to cancer cell death.These findings warrant further investigation of the compound 7 as a potential therapeutic agent for DLBCL.

Radiation-Induced Synthesis of Polyvinylpyrrolidone （PVP） Nanogels

Nanogels-particles of polymer gels having the dimensions in the order of nanometers-are gaining attention for their wide application as biomaterials. Mainly, the nanogels are promising novel pharmaceutical carriers for small biologically active agents, bin macromolecules and can be chemically modified to incorporate various ligands for targeted drug delivery. This important factor has stimulated research on dissimilar science field such as nanotechnology and biotechnology, polymer and materials sciences, biochemistry, radiation chemistry and pharmaceutical sciences. A multitude of techniques have been described for the synthesis of this nanomaterial from polymers. However, the use of ionizing radiation （γ, e-） has demonstrated to be especially suitable for obtaining polymeric nanogels with a high degree of purity for biomedical applications, although the gamma radiation has not been widely utilized for these purposes. The aim of this paper is to develop the synthesis of PVP （polyvynilpyrrolidone） nanogels by gamma irradiation, for their evaluation as potential pharmaceutical carriers. Experiments were performed using argon saturated solution of PVP （0.1-1%）. Crosstinking reactions were carried out in a gamma irradiation chamber with a 60Co source （ISOGAMMA LLCo）, at room temperature. The PVP concentration influence was evaluated in PVP solutions （0.1% and 0.25%） at 15 kGy. The SEM （scanning electron microscopy）, ATR （attenuate total reflection spectroscopy）, DLS （dynamic light scattering）, and viscosimetry were used as characterization techniques.

骨密度联合骨代谢指标在胸腰椎PVP后再骨折中的应用进展

胸腰椎骨折在我国具有较高的发病率,可严重影响患者日常生活,需及时治疗。椎体成形术(vertebroplasty,PVP)是临床用于治疗胸腰椎骨折的一种常见技术,具有疗效高、术后康复快等优势。部分患者于术后可能受到多种因素影响出现再骨折等情况,不仅影响远期预后,严重时可加重病情,增加手术治疗难度。因此,如何评估胸腰椎PVP后再骨折风险与治疗效果,分析影响胸腰椎PVP后再骨折的主要因素,加强高危人群管理,预防胸腰椎PVP再骨折发生至关重要。目前,临床主要将骨密度、骨代谢相关指标作为预测胸腰椎PVP后再骨折的主要观察指标,能够有效预测再骨折发生率,同时还能用于疾病治疗后临床效果的评估,应用价值较高。文章主要从骨密度、骨代谢指标在胸腰椎PVP后再骨折中的应用情况进行综述,分析了骨代谢指标与骨密度在胸腰椎PVP后再骨折中的应用进展,此文的研究结果为骨密度、骨代谢指标后期标准制定提供了借鉴内容。

Preparation and physicochemical characterization of solid dispersion of quercetin and polyvinylpyrrolidone

Aim The objective of this study was to prepare and characterize quercetin-polyvinylpyrrolidone （Qurc-PVP） solid dispersion with the intention of improving its dissolution properties, Methods Qurc-PVP sclid dispersion was prepared by solvent method. The release rate of quercetin was determined from dissolution studies and the physicochemical properties of solid dispersion were investigated by differential scanning calorimetry （DSC）, infrared spectroscopy （IR）, powder X-ray diffraction （PXRD） and scanning electron microscopy （SEM）. Results The results showed that the dissolution rate of quercetin was significantly improved by solid dispersion compared to that of the pure drug and physical mixture, Solubility studies revealed a markedly increase in the solubility of quercetin. The results of DSC and PXRD showed that the quercetin in solid dispersion was amorphous form. From SEM analysis, there was no quercetin crystal observed in the solid dispersions. Conclusion The solubility and dissolution of quercetin were improved by solid dispersion technique.

PVP基多孔炭材料的制备及其电容性能研究

以聚乙烯吡咯烷酮(PVP)为新型含氮碳源,采用碳化活化法,制备聚合物基氮掺杂多孔炭材料,重点研究了碳化活化温度对制备炭材料的电化学性能和电容器电池性能的影响。研究结果表明:不同的碳化活化温度对制备炭材料的形貌有一定影响,XPS分析证实N元素成功掺杂在制备的炭材料里。在三电极体系下,制备的炭材料在800℃表现出最佳的电化学性能和电容性能。此温度下制备的炭材料(PVP-800)在0.5 A·g^(-1)电流密度时,比容量可高达319 F·g^(-1);在10 A·g^(-1)电流密度时,材料的比容量为243 F·g^(-1),显示出良好的电容性能和倍率性能。在二电极体系下,组成的超级电容器能量密度最高为6.77 W·h·kg^(-1),在2 A·g^(-1)的电流密度下循环10 000次后容量保留了最原始的90.7%,体现出优良的比电容性能和循环稳定性。

A new pyrrolidone derivative from Pistacia chinensis

A new N-phenyl-pyrrolidone derivative had been isolated from Pistacia chinesis Bunge. Its structure was elucidated as 4-hydroxy-5-（2-oxo-1-pyrrolidinyl）-benzoic acid, named pistaciamide on the basis of the 1D-NMR, DEPT, HMQC and HMBC spectroscopic techniques. 2007 Xi Kui Liu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Electrospun nanofibers of poly(vinyl pyrrolidone)/Eu^(3+) and its photoluminescence properties

Nanofibers of poly（vinyl pyrrolidone） （PVP）/Eu^3＋ with diameters of 300-900 nm were prepared by using sol-gel processing and electrospinning technique. The products were characterized by scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FT-IR）, and photoluminescence （PL）. The results indicated that, Eu^3＋ was successfully embedded in the onedimensional hybrid nanofibers, and the PVP/Eu^3＋ hybrid nanofibers had favorable photoluminescence properties.

Effect of Added Poly (vinyl pyrrolidone) during Condensation on Properties of Poly(p-phenylene terephthalamide)Pulp

Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)having calcium chloride,in the presence of poly(vinyl pyrrolidone)(PVP)having a viscosity average molecular weight lower than 40 000.It was confirmed that the polycondensation could be accelerated,the inherent viscosity of the polymer could be increased,and the polymers could be fibrillated more easily by the addition of the PVP.FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps.The morphology of the resultant pulps,the effect of viscosity average molecular weight,amount and adding mode of PVP on inherent viscosity,specific surface area,and mean length of the resultant pulps were discussed in detail.And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.

Dissolution Properties of 2-(Dinitromethylene)-5-methyl-1,3-diazacyclopentane in Dimethyl Sulfoxide and N-Methyl Pyrrolidone

The molar enthalpies of dissolution for 2-（dinitromethylene）-5-methyl-1,3-diazacyclopentane（DNMDZ） in dimethyl sulfoxide（DMSO） and N-methyl pyrrolidone（NMP） were measured using an RD496-2000 Calvet microcalorimeter at 298.15 K under atmospheric pressure.Empirical formulae for the calculation of the molar enthalpies of dissolution（Δ diss H） were obtained from the experimental data of the dissolution processes of DNMDZ in DMSO or NMP.The relationships between the rate constant（k） and the molality（b） and between the reaction order（n） and the molality（b） were determined.The corresponding kinetic equations describing the two dissolution processes were dα/dt=10^-2.16（1-α） ^1.01 for the dissolution of DNMDZ in DMSO,and dα/dt=10^-2.02（1-α）^ 0.85 for the dissolution of DNMDZ in NMP,respectively.

STUDY ON THE INTERACTION BETWEEN POLYVINYLPYRROLIDONE AND PLATINUM METALS DURING THE FORMATION OF THE COLLOIDAL METAL NANOPARTICLES

Several PVP-stabilized colloidal platinum metals nanoparticles have been synthesized and characterized by FTIR and TEM.Comparing with the pure PVP,carbonyl groups of PVP in the mixture of PVP and the metal precursors or in the PVP-stabilized metal nanoparticles have obvious peak shifts in FTIR spectra.The peak shifts reveal the interaction between PVP and the metal species.The interaction between PVP and metal precursors has effect on the formation of the colloidal metal nanoparticles.Strength of the intera...

PVP对有机无机复合绝缘FeSi粉芯力学性能与磁性能的影响

在FeSi粉芯的环氧树脂/SiO_(2)绝缘工艺流程中添加PVP作为增强剂,系统研究了PVP添加量对粉芯生坯强度、成品强度以及磁性能的影响规律。研究发现,PVP的引入可增加绝缘层各组分之间以及绝缘层和磁粉之间的粘结力,进而有利于生坯强度的提高。在退火过程中,适量PVP的熔化还有助于SiO_(2)纳米粒子的均匀重排,从而增强成品强度。同时,适量PVP可促进稳定、均匀SiO_(2)绝缘层的形成,进而实现直流偏置性能的优化以及维持良好的磁导率频率稳定性和较低的磁芯损耗。PVP最佳添加量为0.3%(质量分数),相应的FeSi粉芯生坯强度为22 N,成品强度为305.76 N,有效磁导率在20~2000 kHz具有良好的频率稳定性,8000 A/m直流偏置场下的有效磁导率百分比高达86.5%,50 kHz/100 mT的损耗仅为522.7 kW/m^(3)。

Combined gene therapy of endostatin and interleukin 12 with polyvinylpyrrolidone induces a potent antitumor effect on hepatoma

AIM: To study the antitumor effect of combined gene therapy of endostatin and interleukin 12 (IL-12) with polyvinylpyrrolidone (PVP) on mouse transplanted hepatoma.METHODS: Mouse endostatin eukaryotic plasmid (pSecES) with a mouse Igk signal sequence inside and mouse IL-12 eukaryotic plasmid (pmIL-22) were transfected into BHK-22cells respectively. Endostatin and IL-22 were assayed by ELISA from the supernant and used to culture endothelial cells and spleen lymphocytes individually. Proliferation of the latter was evaluated by M-I-r. H22 cells were inoculated into the leg musde of mouse, which was injected intratumorallywith pSecES/PVP, pmIL-12/PVP or pSecES+pmIL-12/PVPrepeatedly. Tumor weight, serum endostatin and serumIL-22 were assayed. Tumor infiltrating lymphocytes, tumormicrovessel density and apoptosis of tumor cells were also displayed by HE staining, CD32 staining and TUNEL.RESULTS: Endostatin and IL-12 were secreted after transfection, which could inhibit the proliferation of endothelial cells or promote the proliferation of spleen lymphocytes.Tumor growth was highly inhibited by 92.8% after injection of pSecES+pmIL-i2/PVP accompanied by higher serum endostatin and IL-22, more infiltrating lymphocytes, fewertumor vessels and more apoptosis cells compared with injection of pSecES/PVP, pmIL-i2/PVP or vector/PVP.CONCLUSION: Mouse endostatin gene and IL-12 gene can be expressed after intratumoral injection with PVP.Angiogenesis of hepatoma can be inhibited synergisticly,lymphocytes can be activated to infiltrate, and tumor cells are induced to apoptosis. Hepatoma can be highly inhibited or eradiated.

Thermo-Responsive Electrospun Nanofibers from Poly( N-isopropylacrylamide )/Polyvinyl Pyrrolidone Blends

A novel nanofiber composite poly(N-isopropylacrylamide)(PNIPAAm)/polyvinyl pyrrolidone(PVP)was successfully prepared by electrospinning.Analogous medicated fibers loaded with ketoprofen(KET)as a model drug were prepared.X-ray diffraction(XRD)demonstrated that the drug was presented in the fibers with an amorphous form.Both scanning and transmission electron microscopy showed that the fibers had an even diameter and smooth surface,and no phase separation was observed.The KET loaded nanofibers did not affect the morphology of the fibers,and no drug aggregation was separated from the polymer fibers.Water contact angle measurements proved that the PNIPAAm/PVP fibers switched from hydrophilic to hydrophobic when the temperature increased the lower critical solution temperature of 32℃.In vitro drug release studies were also undertaken and the result indicated that the PNIPAAm/PVP blend nanofiber presented the properties of the two polymers,having temperature-sensitive systems with sustained release properties.In addition,MTT assay demonstrated that the nanofiber film was non-toxic and suitable for cell growth.Thus,the nanofiber can be used as thermoresponsive carriers for sustained release of poor water soluble drugs.

Kinetic hydrate inhibitor performance of new copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s with TBAB

In oil and gas field, the application of kinetic hydrate inhibitors （KHIs） independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly（N-vinyl-2-pyrrolidone-co-2-vinyl pyridine）s （HGs） is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran （THF） hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.

INTERACTION OF POLYVINYLPYRROLIDONE WITH METAL CHLORIDE AQUEOUS SOLUTIONS

Interactions of polyvinylpyrrolidone (PVP) with metal chlorides (MgCl 2 , CaCl 2 , KCl and BaCl 2 ) have been investigated by viscometric and spectrophotometric techniques in aqueous solutions. Intrinsic viscosity [η] of (PVP) has shown a discontinuity with varying concentration of metal chlorides. The decreasing order of effectiveness of cation is K 1+ > Ca 2+ > Mg 2+ > Ba 2+ for poly(vinylpyrrolidone) solution. Changes in the absorption spectra of the cosolutes were observed in the presence of PVP in the lower limit of the UV-visible region i.e. 200-210 nm. These changes were attributed to interaction of PVP molecules with the cosolute molecules. As the concentration of the cosolute increased, a red shift in the peaks was observed, indicating an increase in interaction between PVP and cosolutes.

MICELLIZATION STUDIES OF DODECYL BENZENESULFONIC ACID AND ITS INTERACTION WITH POLYVINYLPYRROLIDONE

Dodecyl benzenesulfonic acid(DBSA)surfactant was used in the present study to find the effect of concentrationon its electrical conductance in solution from 293-323 K above and below the critical micelle concentration(CMC).Themicellization parameters i.e.degree of counter ion binding(β),aggregation number(n)and number of counter ion micelle(m)were measured.The interaction of DBSA with polyvinylpyrrolidone(PVP)was also studied at 293 K throughconductance and surface tension measure ments.A number of important parameters i.e.critical aggregation concentration(CAC),Gibb's free energy(△G)and binding ratio(R)were determined and the effect of NaCl on the CAC and polymersaturation point(PSP)was also investigated.

Poly(<i>N</i>-Vinyl Pyrrolidone-<i>b</i>-Dimethylsiloxane) Electrospun Nanofibers: Preparation, Characterization and Biological Response

Here we report electrospinning of Poly(dimethylsiloxane-b-vinyl pyrrolidone) (PDMS-b-PVP) based fibrous scaffold materials. The morphology, thermal properties, surface composition, hydrophilicity and fibers formation with different PDMS and PVP chain lengths were determined by using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray photoelectron microscopy (XPS) and X-ray diffraction (RXD) water vapor uptake and water contact angle (WCA). The electrospinning parameters were controlled as well as fiber deposition area. The influence of polymer solution concentration on the morphology of electrospun fibers was also investigated. We checked out the applicability of the electrospun fibers for tissue engineering by the investigation of their capability to support fibroblast cell adhesion, cell growth and proliferation.

Rational Synthesis of Cylindrical Silver Single-crystalline Nanowires via Poly(vinyl pyrrolidone) Reduction of AgCl

We presented a simple yet convenient hydrothermal approach for the large-scale synthesis of uniform cylindrical silver (Ag) single-crystalline nanowires with diameters of about 25 nm and lengths of 1-4 μm. Poly(vinyl pyrrolidone) (PVP) was used as a reducing agent, and AgCl was used as a precursor to deliberately control [Ag^+] at a low degree in the overall reaction process through its dynamic equilibrium by directly reducing AgCl with PVP at a quasi-equilibrium growth condition. The as-obtained products were characterized by powder X-ray diffraction (XRD) patterns, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), infrared spectra (IR) and Raman spectra. Factors such as [PVP], reaction temperature, time, and species of reducing agents and precursors were investigated to have strong influences on the morphologies and structures of the resultant Ag nanostructures. The wire diameter can conveniently be adjusted between 25 and 50 nm by simply adjusting [PVP], reaction temperature and reducing agent species. The as-synthesized silver nanowires can be self-assembled into perfect order arrays after being dried on tin foil due to the PVP coating on the surface, the circular cross-section and the uniform diameter of the Ag nanowires. These special silver nanowires with a core-shell structure as well as their spontaneous self-assembly of order arrays are expected to provide potential applications in flexible conductors, dielectric materials, electromagnetic shielding materials and nano-devices.