The role of remnant cholesterol beyond low-density lipoprotein cholesterol in diabetes mellitus.

BACKGROUND: Previous research has linked elevated low-density lipoprotein cholesterol (LDL-C) and remnant cholesterol (RC) with diabetes mellitus (DM). The present study aims to estimate the RC-related DM risk beyond LDL-C, and to investigate the extent to which the association of RC and DM is mediated via insulin resistance and inflammation. METHODS: We enrolled 7308 individuals without previous history of DM into the present study from the China Health and Nutrition Survey. Fasting RC was calculated as total cholesterol minus LDL-C and high-density lipoprotein cholesterol. Subjects were divided into four groups according to their LDL-C (100 mg/dL) and RC (24 mg/dL) levels to evaluate the role of LDL-C vs. RC on DM. A logistic regression analysis was then employed to evaluate the relationships between the discordant/concordant LDL-C and RC and DM. A mediation analysis was undertaken to identify potential mediators. RESULTS: Of all the participants, a total of 625 (8.55%) patients were newly diagnosed with DM. Compared to the high LDL-C/low RC group, the low LDL-C/high RC group was more common in DM patients. After a multivariate adjustment, elevated LDL-C and RC were associated with DM. Moreover, the low LDL-C/high RC group and the high LDL-C/low RC group manifested a 4.04-fold (95% CI 2.93-5.56) and 1.61-fold (95% CI 1.21-2.15) higher risk of DM, relative to those with low LDL-C/low RC. The subgroup analysis indicated that low LDL-C/high RC was more likely to be related to DM in females. Similar results were also shown when the sensitivity analyses were performed with different clinical cut-points of LDL-C. Insulin resistance and inflammation partially mediated the association between RC and DM. CONCLUSIONS: Our findings provided evidence for RC beyond the LDL-C associations with DM that may be mediated via insulin resistance and the pro-inflammatory state. In addition, women are more susceptible to RC exposure-related DM.

Photoelectrochemical immunosensor for sensitive detection of alpha-fetoprotein based on a graphene honeycomb film.

Alpha-fetoprotein (AFP) in adult serum often appears in early liver cancer. Therefore, early detection of an abnormal elevation of AFP concentration is important for the early diagnosis and treatment of primary liver cancer. In this work, a photoelectrochemical (PEC) electrode was fabricated for AFP-sensitive detection based on a reduced graphene oxide (rGO) honeycomb structure. After layer-by-layer bioconjugation, the immunoassay graphene electrode was modified with anti-AFP antibodies (Ab). Meanwhile, polymer nanoparticles (PFBT dots) were prepared via a nanoprecipitation method. In addition, the AFP was modified by using the PFBT dots and glucose oxidase (GOD), which formed a fluorescent probe (AFP-PFBT-GOD). By the competitive linkage of AFP and AFP-PFBT-GOD onto the anti-AFP modified honeycomb structure electrode, an immunosensor for AFP detection was obtained. During the PEC test, the electrons produced by the catalytic reaction of glucose and GOD can scavenge the photogenerated holes on the PFBT dots, which can reduce the recombination of photogenerated holes and electrons on the PFBT dots. The PEC immunosensor based on a rGO honeycomb structure exhibited a linear detection range of 0.05-100 ng/mL with a detection limit of 0.05 ng/mL. The excellent detection performance of the graphene PEC biosensor provides an opportunity for the early diagnosis of primary liver cancer.

Hydrogen production from methanol aqueous solution by ZnO/Zn(OH)2 macrostructure photocatalysts.

Photocatalytic H2 generation was studied for a series of ZnO/Zn(OH)2 macrostructure photocatalysts. Different ZnO/Zn(OH)2 macrostructures were prepared through a one-step hydrothermal method by adjusting the pH values of the solution and the concentration of dodecyl sulfate. Three different morphologies of the ZnO/Zn(OH)2 macrostructure were synthesized and studied using SEM and XRD. The reflectance spectra revealed that the cone shaped ZnO/Zn(OH)2 macrostructure (ZnO-C) had the lowest reflectivity of UV light. It was found that the photoelectronic properties depend on the morphology of the ZnO/Zn(OH)2 macrostructures. The photocatalytic activity of these ZnO/Zn(OH)2 macrostructure hybrids (about 0.070 mmol g-1 h-1) were higher than that observed for ZnO nanorods (0.050 mmol g-1 h-1). These results suggest the substantial potential of metal oxide materials with macrostructures in photocatalytic water splitting applications.

Enhanced Red Upconversion Luminescence in Yb-Er Codoped NaYF4 Nanocrystals.

In this work the effects of NaYF4:Yb,Er (NYE) structure on the enhanced red upconversion luminescence (UC) was investigated. α-NYE nanocrystals (NCs) and ß-NYE NCs were fabricated by a high temperature decomposition reaction method. The prepared NCs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The results show that the red UC luminescence of α-NYE NCs is significantly enhanced compared with that of ß-NYE. Furthermore, a possible energy transfer mechanism was proposed on the basis of our experimental results.

The Effect of Phase Structures on the Enhanced Red Upconversion Luminescence in NaLuF4:Yb-Er Nanocrystals.

In this work, α-NaLuF4:Yb,Er (NLF) nanocomposites (NCs) and ß-NLF NCs with diameter about ~13 nm were fabricated by a high temperature decomposition reaction method. The effects of NLF structure on the enhanced red upconversion luminescence performance were investigated. Under 980 nm excitation from a laser diode, the α-NLF emitted dominant red UC emission. Furthermore, the possible energy transfer mechanism was proposed on the basis of our experimental results.

Oleic acid-modified LiYF4:Er,Yb nanocrystals for potential optical-amplification applications.

LiYF4:18%Yb, 2%Er nanocrystals and NaYF4:18%Yb,2% Er nanoparticles (NCs) were synthesized by a solvothermal approach using oleic acid (OA) as the surfactant. With the excitation of a 980 nm diode laser, LiYF4:18%Yb, 2%Er NCs exhibit more strong emission than alpha-NaYF4:18%Yb, 2%Er at around 1530 nm. The TEM images showed that the LiYF4:18%Yb, 2%Er NCs have a nearly spherical shape and the size is about 15 nm. The OA-capped LiYF4 NCs have excellent dispersibility in organic solvents. These results showed that LiYF4:18%Yb, 2%Er NCs are a promising material for polymer-based optical waveguide amplifiers.

Preparation and upconversion luminescence of beta-NaYF4:Yb3+, Tm3+/ZnO nanoparticles.

Beta-NaYF4:Yb3+, Tm3+/ZnO core/shell nanoparticles (NPs) were synthesized via a high temperature thermal decomposition method. The as-synthesized core/shell NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and upconversion luminescence spectra (UCL). Under 980 nm laser excitation, the measured intensity of upconversion luminescence (1I6 --> 3H6, 1I6 --> 3F4, and 1D2 --> 3H6) was different with and without ZnO. During the sample preparations, changing the ratio of the solvent affected the ZnO UV absorption efficiency. The results show that the NIR light can be used as the driving source to excite ZnO, thus extending utility rate to the NIR spectral region and enhancing the light harvest rate.

Ultraviolet upconversion emissions of Gd3+ in beta-NaLuF4:Yb3+,Tm3+,Gd3+ nanocrystals.

Beta-NaLuF4:20%Yb,0.5%Tm,x%Gd (x = 10, 20, 30) nanocrystals were synthesized by high temperature thermal decomposition method. X-ray diffraction (XRD) show the as-prepared samples are characteristic of a pure beta-NaLuF4. Transmission electron microscope (TEM) investigations indicate the nanocrystals have particle size of -85 nm with good monodispersity and well-defined crystallographic facets. Particularly, under 980 nm excitation, upconversion (UC) emissions in the UV range of 270-320 nm were observed in these nanocrystals, which further prove that beta-NaLuF4 is an excellent host for building UV compact solid-state lasers or fiber lasers.

Enhanced near-infrared photocatalysis of NaYF4:Yb, Tm/CdS/TiO2 composites.

The previous works by our group (Chem. Commun., 2010, 46, 2304-2306; ACS Catal., 2013, 3, 405-412; Phys. Chem. Chem. Phys., 2013, 15, 14681-14688) have reported the near-infrared-driven photocatalysis of broadband semiconductor TiO2 or ZnO that was combined with upconverting luminescence particles to form a core-shell structure. However, the photocatalytic efficiency is low for this new type of photocatalysts. In this work, NaYF4:Yb,Tm/CdS/TiO2 composites for NIR photocatalysis were prepared by linking CdS and TiO2 nanocrystals on the NaYF4:Yb,Tm microcrystal surfaces. CdS and TiO2 were well interacted to form a heterojunction structure. The energy transfer between NaYF4:Yb,Tm and the semiconductors CdS and TiO2 was investigated by steady-state and dynamic fluorescence spectroscopy. The photocatalytic activities of the as-prepared composites were evaluated by the degradation of methylene blue in aqueous solution upon NIR irradiation. Significantly, it was found that the united adhesions of CdS and TiO2 on the NaYF4:Yb,Tm particle surfaces showed much higher catalytic activities than the individual adhesion of CdS or TiO2 on the NaYF4:Yb,Tm surfaces. This was attributed mainly to the effective separation of the photogenerated electron-hole pairs due to the charge transfer across the CdS-TiO2 interface driven by the band potential difference between them. The presented composite structure of upconverting luminescence materials coupled with narrow/wide semiconductor heterojunctions provides a new model for improved NIR photocatalysis.

Near-infrared photocatalysis of ß-NaYF4:Yb3+,Tm3+@ZnO composites.

A novel near-infrared (NIR)-responsive photocatalyst, ß-NaYF4:Yb(3+),Tm(3+)@ZnO composites, was prepared by a two-step high temperature thermolysis method. In the NIR-responsive photocatalysis, ß-NaYF4:Yb,Tm served as a NIR-to-UV upconverter and provided "UV light" or "necessary energy" to the ZnO catalyst. The energy transfer in the composites and the mixtures of ß-NaYF4:Yb,Tm and ZnO was studied by using steady-state and dynamic fluorescence spectroscopy. The NIR photocatalytic activities were investigated by the decomposition of Rhodamine B. It was found that the energy transfer processes dominated the overall photocatalytic activities, and the generation of hydroxyl radicals was the origin of organic pollutant decomposition under NIR irradiation.

Fabrication of nanostructured hydroxyapatite and analysis of human osteoblastic cellular response.

Nano-sized hydroxyapatite (HA) powders were produced by a hydrothermal method and a precipitation method. Spark plasma sintering (SPS) was used to fabricate nanostructured HA (NHA) using nano-sized HA powders as a precursor. Conventional sintering was employed to produce microstructured HA (MHA). Characteristics of HA powders and HA bulk ceramics after sintering were investigated by XRD, FTIR, SEM, TEM, particle size distribution, and AFM. Dense compacts consisting of equiaxed grains with an average grain size of approximately 100 nm were obtained by SPS. Human osteoblasts were cultured on both NHA and MHA and cell attachment, proliferation, and mineralization were evaluated. After 90 min incubation, the cell density on NHA surface was significantly higher than that of MHA and glass control, whereas average cell area of a spread cell was significantly lower on NHA surface compared to MHA and glass control after 4 h incubation. Matrix mineralization was determined after 7 and 14 days incubation by using alizarin red assay combined with cetylpyridinium chloride extraction. NHA shows significant enhancement (p < 0.05) in mineralization compared to MHA. Results from this study suggest that NHA may be a much better candidate for clinical use in terms of bioactivity.

Electrophoretic deposition of hydroxyapatite coating on Fecralloy and analysis of human osteoblastic cellular response.

Hydroxyapatite has been successfully deposited onto Fecralloy substrate (a metal alloy with 22% Cr, 4.8% Al) by electrophoretic deposition in an attempt to promote the adhesion between coating and substrate, consequently to extend the lifetime of implants. Fecralloy has the ability to generate a dense and stable alpha-Al(2)O(3) layer "in situ" during thermal treatment, which will highly improve the adhesion and the corrosion resistance of the coating system. Phases and morphologies of HA coating were found to vary after sintering according to XRD and SEM analysis. Besides the physicochemical characterization, the effects of the Fecralloy, thermally generated oxide layer, and HA coating on the early and late responses of osteoblasts in vitro were determined. Cellular morphology and proliferation were studied up to 7 days. Quantitative assays of mineralization were conducted up to 14 days. Osteoblasts showed increased cell spreading and cell proliferation on metal substrates, with significantly higher mineralization on HA coating. The results in this study proved that Fecralloy is a biocompatible metal and the HA coating on Fecralloy provides a good candidate for orthopaedic and dental implants.