Investigation of antimicrobial properties and in-vitro bioactivity of Ce3+-Sr2+dual-substituted nano hydroxyapatites

Dual doped calcium apatite has been widely focused as it enhances the osteoconductive property for the possible applications in orthopedic and dental implants. In this work, we investigate the antimicrobial and bioactive properties of cerium/strontium (Ce³⁺/Sr²⁺) co-substituted hydroxyapatite (HA) nanoparticles synthesized by sol-gel assisted precipitation method. The structure, morphology, functional groups, photoluminescence, and thermal stability of the developed systems are examined. The comparative studies performed among the pure HA, Sr²⁺, and Ce³⁺-substituted HA nanoparticles illustrate higher antibacterial activity with lowered apatite-forming ability and biocompatibility for the Ce³⁺-substituted HA. However, the Ce³⁺/Sr²⁺co-substituted HA exhibits better biocompatibility, apatite-forming ability, and good antimicrobial properties. Sr²⁺ ion inclusion leads to better biological properties and compromise the cytotoxic nature of the Ce³⁺-HA. In addition, the Ce³⁺/Sr²⁺-HA nanoparticles prevent thermal decomposition up to 700°C, pointing also toward the possibility of this co-substituted HA in bone implant applications.     

Detecting anomalous packets in network transfers: investigations using PCA,autoencoder and isolation forest in TCP

Machine Learning - Large-scale scientific workflows rely heavily on high-performance file transfers. These transfers require strict quality parameters such as guaranteed bandwidth, no packet loss...     

Fumed SiO2 nanoparticle reinforced biopolymer blend nanocomposites with high dielectric constant and low dielectric loss for flexible organic electronics

In the present study, fumed silica (SiO₂) nanoparticle reinforced poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) blend nanocomposite films were prepared via a simple solution‐blending technique. Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), X‐ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to elucidate the successful incorporation of SiO₂ nanoparticles in the PVA/PVP blend matrix. A thermogravimetric analyzer was used to evaluate the thermal stability of the nanocomposites. The dielectric properties such as dielectric constant (?) and dielectric loss (tan δ) of the PVA/PVP/SiO₂ nanocomposite films were evaluated in the broadband frequency range of 10^?2 Hz to 20 MHz and for temperatures in the range 40–150 °C. The FTIR and UV–vis spectroscopy results implied the presence of hydrogen bonding interaction between SiO₂ and the PVA/PVP blend matrix. The XRD and SEM results revealed that SiO₂ nanoparticles were uniformly dispersed in the PVA/PVP blend matrix. The dielectric property analysis revealed that the dielectric constant values of the nanocomposites are higher than those of PVA/PVP blends. The maximum dielectric constant and the dielectric loss were 125 (10^?2 Hz, 150 °C) and 1.1 (10^?2 Hz, 70 °C), respectively, for PVA/PVP/SiO₂ nanocomposites with 25 wt % SiO₂ content. These results enable the preparation of dielectric nanocomposites using a facile solution‐casting method that exhibit the desirable dielectric performance for flexible organic electronics. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44427.     

Solution-processed white graphene-reinforced ferroelectric polymer nanocomposites with improved thermal conductivity and dielectric properties for electronic encapsulation

The recent surge in graphene research has stimulated interest in the investigation of various two-dimensional (2D) nanomaterials, including 2D boron nitride (BN) nanostructures. Among these, hexagonal boron nitride nanosheets (h-BNNs; also known as white graphene, as their structure is similar to that of graphene) have emerged as potential nanofillers for preparing thermally conductive composites. In this work, hexagonal boron nitride nanoparticles (h-BNNPs) approximately 70 nm in size were incorporated into a polyvinylidene fluoride (PVDF) matrix with different loadings (0–25 wt.%). The PVDF/h-BNNP nanocomposites were prepared by a solution blending technique and characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), polarized optical microscopy (POM) and scanning electron microscopy (SEM). In addition, the thermal conductivity and dielectric properties of the nanocomposites were investigated. The incorporation of h-BNNPs in the PVDF matrix resulted in enhanced thermal conductivity. The highest value, obtained at 25 wt.% h-BNNP loading, was 2.33 W/mK, which was five times that of the neat PVDF (0.41 W/mK). The thermal enhancement factor (TEF) at 5 wt.% h-BNNP loading was 78%, increasing to 468% at 25 wt.% h-BNNP loading. The maximum dielectric constant of approximately 36.37 (50Hz, 150 °C) was obtained at 25 wt.% h-BNNP loading, which was three times that of neat PVDF (11.94) at the same frequency and temperature. The aforementioned results suggest that these multifunctional and high-performance nanocomposites hold great promise for application in electronic encapsulation.     

Soft chemistry synthesis of MxV2O5 + ε·nH2O (MCo, Ni, Cu, Zn) nanowires

Recently a simple method was used for preparing nanowires M_xV₂O_5 + ε·nH₂O (MMg, Mn). It consists of mixing a boiling solution of vanadium oxide with the corresponding metal nitrate. In the present paper, this method was explored for preparing other nanowires layered M_xV₂O_5 + ε·nH₂O compounds (MTi, Cr, Fe, Co, Ni, Cu, and Zn). The results obtained show that If the precipitates are formed immediately after mixing the two solutions, such in case of titanium, chromium and iron, the structure and particles shape of the products are different from the layered compound M_xV₂O_5 + ε·nH₂O. However, if the precipitates start to appear only after several minutes of stirring, such in case of cobalt, nickel, copper and zinc, the phases obtained are similar to layered nanowires M_xV₂O_5 + ε·nH₂O. The amount of the metal inserted “M” was found to be lower than 25 at.% in all as-prepared samples. Nickel containing sample shows the highest inserted amount.     

衬底温度对NiO:Cu/ZnO异质pn结的光电性能影响

利用磁控溅射方法改变衬底温度,制备了一系列Ni O:Cu/ZnO异质pn结。实验结果表明,当衬底温 度从室温升高到300℃时,NiO:Cu/ZnO异质pn结的整流特性明显得到 改善;与此同时,NiO:Cu/ZnO异质 pn结的光学透过率也从40%增大到80%。这可能是由于NiO:Cu薄膜结晶质量改善,薄膜内 缺陷减少所致。 继续增加衬底温度至400℃,异质结的整流特性有所削弱,这可能是 由于生长在异质结下层 的NiO:Cu薄膜影响了其上ZnO薄膜的生长,进而影响到异质结的整流特性。这一结论,得到 X射线衍射(XRD)、原子力显微镜(AFM)和紫外(UV)谱测试结果的支持。     

MicroRNA-16 Restores Sensitivity to Tyrosine Kinase Inhibitors and Outperforms MEK Inhibitors in KRAS-Mutated Non-Small Cell Lung Cancer

Background: Non-small cell lung cancer (NSCLC) is the leading cause of cancer death worldwide. Chemotherapy, the treatment of choice in non-operable cases, achieves a dismal success rate, raising the need for new therapeutic options. In about 25% of NSCLC, the activating mutations of the KRAS oncogene define a subclass that cannot benefit from tyrosine kinase inhibitors (TKIs). The tumor suppressor miR-16 is downregulated in many human cancers, including NSCLC. The main objectives of this study were to evaluate miR-16 treatment to restore the TKI sensitivity and compare its efficacy to MEK inhibitors in KRAS-mutated NSCLC. Methods: We performed in vitro and in vivo studies to investigate whether miR-16 could be exploited to overcome TKI resistance in KRAS-mutated NSCLC. We had three goals: first, to identify the KRAS downstream effectors targeted by mir-16, second, to study the effects of miR-16 restoration on TKI resistance in KRAS-mutated NSCLC both in vitro and in vivo, and finally, to compare miR-16 and the MEK inhibitor selumetinib in reducing KRAS-mutated NSCLC growth in vitro and in vivo. Results: We demonstrated that miR-16 directly targets the three KRAS downstream effectors MAPK3, MAP2K1, and CRAF in NSCLC, restoring the sensitivity to erlotinib in KRAS-mutated NSCLC both in vitro and in vivo. We also provided evidence that the miR-16–erlotinib regimen is more effective than the selumetinib–erlotinib combination in KRAS-mutated NSCLC. Conclusions: Our findings support the biological preclinical rationale for using miR-16 in combination with erlotinib in the treatment of NSCLC with KRAS-activating mutations.     

Latex coatings containing antifeedants: Formulation,characterization, and application for protection of conifer seedlings against pine weevil feeding

Latex-based coatings for protection of tree seedlings against pest insect feeding are evaluated with respect to surface-, mechanical-, and release properties and antifeedant activity. The latex dispersion Eudragit copolymer (EC) was used to form the coatings, 2,6-di-tert-butyl-4-methylphenol (BHT) and cis-dihydropinidine (Alk) as antifeedants, and a thickener and a alkylglucoside based nonionic surfactant were used as additives to optimize the release- and mechanical properties of coatings. Coating characterization was performed with respect to surface morphology (atomic force microscopy, AFM) and surface wetting (contact angle), as well as to mechanical (tensile stress- and tensile strain at break) properties. Surface smoothness and wettability as well as elasticity increased with addition of the surfactant. The optimized coatings were found to be elastic and water resistant at 3–6 wt.% of BHT and 3 wt.% of surfactant. BHT was released into SDS/water at very low rates. Several formulations of BHT and Alk were efficient in preventing the feeding on conifer bark by a pine insect, Hylobius abietis both in laboratory (no-choice) and in field (3 months) tests.