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Apolipoprotein (apo) E4 is a major risk factor for Alzheimer's disease, and many studies have suggested that apoE has isoform-specific effects on the deposition or clearance of amyloid beta (A beta) peptides. We examined the effects of apoE isoforms on the processing of amyloid precursor protein (APP) and on A beta production in rat neuroblastoma B103 cells stably transfected with human wild-type APP695 (B103-APP). Lipid-poor apoE4 increased A beta production in B103-APP cells to a greater extent than lipid-poor apoE3 (60% vs. 30%) due to more pronounced stimulation of APP recycling by apoE4 than apoE3. The difference in A beta production was abolished by preincubating the cells with the receptor-associated protein (25 nM), which blocks the low-density lipoprotein receptor-related protein (LRP) pathway, or by reducing LRP expression by small interference RNA. The differences were also attenuated by replacing Arg-61 with threonine in apoE4 or pretreating apoE4 with small molecules, both of which abolish apoE4 intramolecular domain interaction. Thus, apoE4 appears to modulate APP processing and A beta production through both the LRP pathway and domain interaction. These findings provide insights into why apoE4 is associated with increased risk for Alzheimer's disease and may represent a potential target for drug development.

Mn3O4 was prepared by hydrothermal method with 180 °C as reaction temperature and 10 h as reaction time. The obtained samples were bar-like samples with high purity were evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical performance of Mn3O4 was improved by Sn-doping. The specific capacitance of the composites obtained by compounding the modified materials with graphene was greatly increased and their cyclic voltammetric curves were rectangular, which shows that the graphene modified Mn3O4 has a pleasurable development prospect. For the pure Mn3O4, Sn-Mn3O4 and Sn-Mn3O4 / graphene composite, the specific capacitance of 21 F·g-1, 30 F·g-1 and 215 F·g-1 were manifested by electrochemical work station, respectively. The results show that stannum and graphene greatly enhances the electrochemical performance of Mn3O4. [ABSTRACT FROM AUTHOR]

Various toxic organic pollutants can be degraded or mineralized into biogradable small molecules or carbon dioxide by photocatalysis. And the keystone of photocatalysis research is pursuing highly efficient photocatalysis. Zinc oxide (ZnO) nanomaterials and graphene nanomaterials (GNS) were prepared from expanded graphite according to modified Hummers method. ZnO/GNS were prepared by ultrasound method. The samples were analyzed by XRD, TEM, FT-IR, UV-vis and Raman spectroscopy. Expanded graphite through deep oxidation and reduction can be thin layer of graphene. Then ZnO/GNS was constructed by simple ultrasound method. And photocatalytic performance of the composite structure showed was increased drastically. Thus, the structure we built is necessary to environment. [ABSTRACT FROM AUTHOR]

Compared with common quantum dots, the doped ZnS quantum dots (ZnS QD) have outstanding properties in luminescence, electricity and other fields and have became research focus in material science. In this research, ZnS:Na+,Mg2+ QD, ZnS:Na+,Cr3+ QD and ZnS:Mg2+,Cr3+ QD were prepared by aqueous-phase synthesis. The quantum dots were analyzed and characterized by XRD, TEM, fluorescence spectra and IR spectra. The results showed that double-doping didn't have effect on the structure of ZnS QD. The ZnS QD approximated sphere with reunion phenomenon and had obvious lattice structure. The doping of metal ions could regulate the fluorescence properties of the ZnS QD. [ABSTRACT FROM AUTHOR]

Using thiourea as surface modifier, ZnS:Mg2+ quantum dots are successfully prepared by aqueous phase method. X-ray diffractometer, TEM and fluorescence spectrophotometer are used to analyze structure properties and luminescent properties of ZnS:Mg2+ quantum dots. At the same time, by the infrared absorption spectrum, we analyze the formation mechanism of ZnS:Mg2+ quantum dots. The results show that the as-obtained samples are cubic sphalerite structures and are approximate to spheres. They distribute uniformly but have adhesion phenomenon. The measures of quantum dots are about 4nm. The samples emit green light at 525nm. The best preparing conditions are that the doping concentration of Mg2+ is 1.5%, thiourea/ZnS is 1.5:1 and pH value is 13. [ABSTRACT FROM AUTHOR]

MnO2 materials are prepared through a hydrothermal process. Sn-doping and composite graphene are both achieved simultaneously during the hydrothermal reaction then obtain the electrode materials of supercapacitors. Morphology, structure and electrochemical properties of the samples are evaluated by X-ray diffraction(XRD), scanning electron microscopy (SEM), and electrochemical work station. The results show that, the specific capacitance of 49 F·g-1, 283 F·g-1 and 312 F·g-1 are exhibited for the pure MnO2, Sn- MnO2 and Sn-MnO2 / graphene composite, respectively, indicating that stannum and graphene greatly enhances the electrochemical performance of MnO2. [ABSTRACT FROM AUTHOR]

An improved method for the preparation of graphene quantum dots (GQDs) is described. The samples are characterized in terms of morphological, structural, and optical properties which are evaluated by X-ray diffraction (XRD), transmission electron microscopy (TEM), the Photoluminescence (PL) spectrum and Fourier transform infrared (FTIR) spectra correspondingly. The graphene oxide (GO) go through with microwave expansion treatment first, then followed by solvothermal process. The research shows that with the increase of the microwave time and microwave power, the fluorescence intensity of GQDs first increased and then decreased, when the GO sheets are under 500 W microwave-assisted treatment for 5 min, the intensity gets the strongest. The solvothermal temperature had no effect on the fluorescence emission wavelength of the graphene quantum dots, the fluorescence emission spectra red shifts as the microwave treatment time is increased. The fluorescence emission spectrum of GQDs that synthesized by this method perform excitation-dependent PL behaviors. [ABSTRACT FROM AUTHOR]

A microcalorimeter (Setaram c-80) was used to study the thermokinetics of the hydration process of calcium phosphate cement (CPC), a biocompatible biomaterial used in bone repair. The hydration enthalpy was determined to be 35.8 J g–1 at 37.0°C when up to 80 mg CPC was dissolved in 2 mL of citric buffer. In the present study, parameters related to time constants of the calorimeter were obtained by fitting the recorded thermal curves with the function θ= Ae–?t(1– e–?2t). The real thermogenetic curves were then retrieved with Tian function and the transformation rate of the hydration process of CPC was found to follow the equation α=1–[1–(0.0075 t)3]3. The microstructures of the hydrated CPC were examined by scanning electron microscopy. The nano-scale flake microstructures are due to crystallization of calcium phosphate and they could contribute to the good biocompatibility and high bioactivity. [ABSTRACT FROM AUTHOR]

An AgBiS2/BiOI composites with different proportions were prepared by precipitation method, and their catalytic activity was studied by degrading RhB (100 mg/L) under simulated light conditions. The results showed that the photocatalytic activity of AgBiS2/BiOI composite was the best when the doping amount of AgBiS2 was 4 wt. % (the degradation rate was about 94%). Compared with pure BiOI, the degradation rate of RhB increased by 24%. After 5 cycles of experiments, the degradation rate of the material can still reach 94%, indicating that the AgBiS2/BiOI composite has good stability. [ABSTRACT FROM AUTHOR]

Porous alumina ceramics with different pore composition (intrinsic pores and extrinsic pores) were prepared by gel injection molding process combined with pore forming technology and effects of intergranular pores and extrinsic pores on thermal shock fracture resistance and thermal shock damage resistance were studied. The results show that, when the solid phase content or total porosity is the same, the porous ceramic material with extrinsic pores has higher damage tolerance, thermal shock critical temperature difference (ΔTc) and residual strength retention rate. A ratio parameter (KIC/E) for evaluating the thermal shock stability of materials is deduction. The larger the ratio is, the better the thermal shock resistance of materials. [ABSTRACT FROM AUTHOR]

One dimension CaTiO3: Eu3+, Gd3+ nanofibers have been prepared by a combination method of sol-gel process and electrospinning. X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric and differential thermal analysis (TG-DTG), and photoluminescence (PL) properties were used to characterize the resulting samples. SEM results indicate the surface the as-formed fibers are rough, and the as-prepared nanofibers consist of nanoparticles. The photoluminescence properties exhibit that the obtained phosphors can be efficiently excited in the range from 370 to 420 nm. Under 398nm excitation, the phosphors show the characteristic emission of Eu3+, i.e. 5Do-7F15Do-7F2 5Do-7F3 transitions. A certain amount of Gd3+ and Eu3+ is contributed to the intensity of light emission. [ABSTRACT FROM AUTHOR]

The Sr2TiO4:Eu3+, Ce3+ phosphors were synthesized by sol-gel method. Multiple techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM) were used to examine the surface morphology and structural properties of Sr2TiO4:Eu3+, Ce3+ phosphors. The optical properties were presented and discussed in terms of photoluminescence (PL), photoluminescence excitation (PLE) and ultraviolet-visible (UVVIS) spectra. The as-obtained Sr2TiO4:Eu3+, Ce3+ phosphors showed higher PL emission intensity (at 588, 611 nm). These peaks were attributed to electronic transition (5D0-7F1, 5D0-7F2) of Eu3+. After being irradiated with ultraviolet light, the phosphor samples emitted white light with excitation at 394 nm. The UV-VIS absorption spectra showed strong absorption in the ultraviolet region, suggesting potential applications in many fields. [ABSTRACT FROM AUTHOR]

Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum, energy transfer mechanism, and color brightness of the samples are studied using scanning electron microscopy, X-ray diffraction, fluorescence spectrophotometry, and color coordinate (CIE) calculations. Furthermore, the effects of the synthesis temperature, holding time, rare-earth element doping amount, and charge compensation agent on the luminescence intensity of the samples are investigated. Results show that the luminescent effect of the sample containing Na+ as the charge compensator is better than that of the sample containing K+. When the concentrations of Dy3+ and Eu3+ are 2 and 3%, respectively, the calcination temperature is 700°C, and the holding time is 3 h, the samples exhibit the best luminescence performance and the color coordinates are in the white-light region, indicating a good white-light luminescent material. [ABSTRACT FROM AUTHOR]

The blue phosphor material in trichromatic phosphors for white light emitting diodes (WLED) has a great application prospect. Therefore, the silicate blue luminescent material BaCaSiO4:Eu2+, Gd3+ for WLED was prepared by combustion method. Using urea as combustion agent, the optimum sintering temperature and sintering time of primary sintering and secondary sintering were studied. The main emission peak of the luminescent material is located at 499nm, which was the transition emission peak of 4f65d¹→4f7 of Eu2+, and the luminescence properties of silicate luminescent material could be enhanced by doping a certain amount of Gd3+. The color of light emitted from the luminescent material was pure blue according to the color coordinates obtained from the emission spectrum. [ABSTRACT FROM AUTHOR]

A CQDs/CoO/g-C3N4 nanocomposite used for photocatalytic degradation was designed and fabricated in this paper. The effects of carbon quantum dots (CQDs) content and synthesis temperature on photocatalytic properties of nanocomposites were studied. The results show that the solar energy utilization efficiency of CQDs/CoO/g-C3N4 nanocomposite is twice that of pure g-C3N4 when the content of CQDs is 4.5 wt%. The improvement of photocatalytic performance of nanocomposite is mainly attributed to the synergistic effect of the junction/interface between g-C3N4, CoO and CQDs. [ABSTRACT FROM AUTHOR]

Abstract: Age estimation is of great significance in the fields of criminal investigation and forensic identification. It can provide the age information of individuals to judicial departments to facilitate the development of judicial work. In recent years, age estimation methods expanded from the morphological level to the molecular biology level. With the rapid development of epigenetics represented by DNA methylation, and the advancement of DNA methylation detection technology together with the detection platform, many age estimation methods based on DNA methylation biomarkers, or using several biological fluids, such as blood, blood stains, saliva, semen stains, etc. are developed. Currently, researches related to age estimation based on DNA methylation are relatively widely carried out. This paper summarizes the researches on age estimation based on DNA methylation, in order to provide references for related studies and forensic applications., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine.)

We investigated type II deiodinase (DIO2) polymorphisms and serum thyroid hormone levels in subjects with mild cognitive impairment (MCI) in a Uygur population. We studied the DIO2 Thr92Ala (rs225014) and ORFa-Gly3Asp (rs12885300) polymorphisms of 129 unrelated MCI cases and 131 matched controls. All subjects were genotyped using SNaPshot SNP genotyping assays. Serum thyroid hormone levels were measured by radioimmunoassay. Levels of serum triiodothyronine and thyroxine in the MCI group were significantly lower than those in the control group. Genotype and allele frequencies in the DIO2 gene between the MCI and control groups were not significantly different. There was no association in genotype and allele frequencies of Thr92Ala between genders in both groups. ORFa-Gly3Asp genotype and allele frequencies were significantly different in patients and controls by gender. The Asp allele was less frequent among male MCI patients compared to controls (odds ratio = 0.471, 95% confidence interval = 0.261-0.848). However, female Asp carriers were more frequent among MCI patients than among controls (odds ratio = 2.842, 95% confidence interval = 1.326-6.09). Serum levels of triiodothyronine and thyroxine were lower in individuals of the Ala/Ala genotype than in those with the Thr/Thr or Thr/Ala genotype. Serum levels of triiodothyronine were lower in male Gly/Gly carriers than in Gly/Asp or Asp/Asp carriers. Decreased serum levels of triiodothyronine and thyroxine may influence the incidence of MCI in the Uygur population. DIO2 gene polymorphisms may play a role in the incidence of MCI in male patients.

We examined whether the X-ray repair cross-complementing group 1 (XRCC1) Arg399Gln polymorphism is a risk factor for bladder cancer by conducting a meta-analysis. We searched the Pubmed and Embase databases for study retrieval. This meta-analysis examined 16 case-control studies, including 892 prostate cancer cases and 1020 healthy controls. Meta-analysis results based on these studies showed no significant association between the XRCC1 Arg399Gln polymorphism and bladder cancer risk in comparisons of the glutamine (Gln) allele vs arginine (Arg) allele, Arg/Arg vs (Gln/Gln + Gln/Arg), Gln/Gln vs (Gln/Arg + Arg/Arg), Gln/Gln vs Arg/Arg, and Gln/Arg vs Arg/Arg [odds ratio (OR) = 0.96, 95% confidence interval (CI) = 0.80-1.16, P = 0.70; OR = 1.13, 95%CI = 0.70-1.82, P = 0.62; OR = 0.92, 95%CI = 0.79-1.07, P = 0.29; OR = 0.90, 95%CI = 0.69-1.16, P = 0.42; OR = 0.89, 95%CI = 0.75-1.05, P = 0.17, respectively]. In subgroup analysis by ethnicity, no association was observed between the XRCC1 Arg399Gln polymorphism and bladder cancer risk in Caucasian, Mongoloid, or black populations. We identified no association between the XRCC1 Arg399Gln polymorphism and bladder cancer risk.

Human apolipoprotein E4 (apoE4) binds preferentially to lower density lipoproteins, including very low density lipoproteins, and is associated with increased risk of atherosclerosis and neurodegenerative disorders, including Alzheimer's disease. This binding preference is the result of the presence of Arg-112, which causes Arg-61 in the amino-terminal domain to interact with Glu-255 in the carboxyl-terminal domain. ApoE2 and apoE3, which have Cys-112, bind preferentially to high density lipoproteins (HDL) and do not display apoE4 domain interaction. Mouse apoE, like apoE4, contains the equivalent of Arg-112 and Glu-255, but lacks the critical Arg-61 equivalent (it contains Thr-61). Thus, mouse apoE does not display apoE4 domain interaction and, as a result, behaves like human apoE3, including preferential binding to HDL. To assess the potential role of apoE4 domain interaction in atherosclerosis and neurodegeneration, we sought to introduce apoE4 domain interaction into mouse apoE. Replacing Thr-61 in mouse apoE with arginine converted the binding preference from HDL to very low density lipoproteins in vitro, suggesting that apoE4 domain interaction could be introduced into mouse apoE in vivo. Using gene targeting in embryonic stem cells, we created mice expressing Arg-61 apoE. Heterozygous Arg-61/wild-type apoE mice displayed two phenotypes found in human apoE4/E3 heterozygotes: preferential binding to lower density lipoproteins and reduced abundance of Arg-61 apoE in the plasma, reflecting its more rapid catabolism. These findings demonstrate the successful introduction of apoE4 domain interaction into mouse apoE in vivo. The Arg-61 apoE mouse model will allow the effects of apoE4 domain interaction in lipoprotein metabolism, atherosclerosis, and neurodegeneration to be determined.

The defective binding of apolipoprotein (apo) E2 to lipoprotein receptors, an underlying cause of type III hyperlipoproteinemia, results from replacement of Arg 158 with Cys, disrupting the naturally occurring salt bridge between Asp 154 and Arg 158. A new bond between Asp 154 and Arg 150 is formed, shifting Arg 150 out of the receptor binding region. Elimination of the 154-150 salt bridge by site-directed mutagenesis of Asp 154 to Ala restored the receptor binding activity to near normal levels. The X-ray crystal structure of apoE2 Ala 154 demonstrated that Arg 150 was relocated within the receptor binding region. Our results demonstrate that defective binding of apoE2 occurs by a novel mechanism of the replacement of one salt bridge with another.

Human apolipoprotein (apo) E4 (arginine at residue 112) preferentially associates with very low density lipoproteins (VLDL), and apoE3 (cysteine at 112) associates with high density lipoproteins. It has been postulated that the amino-terminal domain, which contains residue 112, influences the lipoprotein preference by interacting with the carboxyl-terminal domain, which contains the lipid-binding region. To delineate the region in the carboxyl-terminal domain mediating lipoprotein binding and involved in isoform preference, we produced truncated apoE3 and apoE4 variants (terminating at residues 251, 260, 266, or 272) in Escherichia coli and assessed them for lipoprotein association. This analysis suggested that residues 260-272 contain important determinants for complete lipoprotein association and isoform preferences. To determine whether positive charge at residue 112 was an absolute requirement for the apoE4 VLDL preference, we compared the distributions of rabbit apoE (equivalent to apoE3, with cysteine at a position corresponding to 112), canine apoE (arginine at the corresponding site), and cysteamine-treated rabbit apoE (cysteine converted to a positively charged residue). Surprisingly, all distributed like human apoE3, suggesting that positive charge at a position corresponding to 112 was not directly responsible for the isoform preference and that other residues in the amino-terminal domain were involved. To determine which residues were involved, the structure of the apoE4 22-kDa fragment (the amino-terminal two-thirds of the molecule) was determined to 2.5 A by x-ray crystallography. Compared with the known four-helix bundle structure of apoE3, the only significant differences in the apoE4 structure were that glutamic acid 109 formed a salt bridge with arginine 112 and that the arginine 61 side chain was displaced to a new position. Site-directed mutagenesis of glutamic acid 109 in apoE3 and arginine 61 in apoE4 demonstrated that the position of the arginine 61 side chain in apoE4 was critical in determining apoE4 lipoprotein distribution, suggesting that arginine 61 interacted with the carboxyl-terminal domain to direct binding to VLDL.

A genetic classification of Alzheimer disease(s) (AD) is presented. We describe a potential metabolic process in individuals who inherit apolipoprotein E-epsilon 4 (APOE4, gene; apoE4, protein) alleles, leading to increased risk and earlier age of onset of late-onset Alzheimer disease. Apolipoprotein E-epsilon 3 (apoE3) binds to tau protein, possibly slowing the initial rate of tau phosphorylation and self-assembly into paired helical filaments (PHFs); apoE4 does not bind tau. Tau promotes microtubule assembly and stabilizes microtubules; hyperphosphorylated tau does not bind, thereby destabilizing microtubules. Hyperphosphorylated tau may self-assemble into PHFs. Over time a bias toward destabilization of microtubules and the formation of neurofibrillary tangles may occur in individuals who inherit APOE4 alleles, leading to a shorter functional neuronal life span. This hypothesis focuses attention on two important aspects of AD research design: (1) Although the inheritance of APOE4 is associated with increased risk and decreased age of onset, apoE4 does not directly cause the disease. Our data point to the absence of an important function of apoE3 or apoE2 in individuals who do not inherit these alleles as the genetically relevant metabolic factor. This has important implications for design of experiments directed toward understanding the relevant neuronal metabolism. (2) Should this hypothesis be proven and confirmed, targets for pharmaceutical therapy designed to mimic the metabolic function of apoE3 or apoE2 become a realistic preventive strategy.