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There are still some problems in the study of hydraulic fracture (HF) network evolution in cemented naturally fractured reservoirs, such as microseismic mapping showing exaggerated stimulated reservoir volume in some cases. In addition, the dominant role of natural fracture (NF) cementation strength, injection rate, in situ stress difference, NF distribution, and fracture initiation sequence of perforations in synthetically influencing fracture network formation needs to be further studied. For this purpose, a three‐dimensional matrix hexahedral element global coupled 0‐thickness cohesive element hydraulic fracturing model was developed. Results show that each interaction between HF and NF causes HF diameter shrinkage, which increases the propagation pressure of HF. When the cementation strength of the NF is low, the HF tends to deviate toward the tip of the NF to form a complex fracture network. Increasing the injection rate and the number of NFs can significantly enhance the complexity of the HF network, but does not change the HF and NF interaction pattern. The in situ stress differences dominate the morphology of the HF network when the cementation strength of NFs is constant. The stress interference of multiple fractures under segmented fracturing may form "S"‐shaped HFs, and the HFs are difficult to maintain a symmetrical morphology in the direction of the well axis. In addition, some NFs in inactivated damaged zones have developed a certain width geometrically due to the induced effect of HF, but they are still isolated by the low permeability matrix and might only generate some microseismic events. [ABSTRACT FROM AUTHOR]

Mesenchymal stem cells (MSCs) have been suggested for pancreatic islet repair in Type 1 diabetes mellitus (T1DM). This study aimed to investigate the effect of human umbilical cord MSCs (hUC‐MSCs) transfected with tissue inhibitors of matrix metalloproteinase (TIMP)‐1 on the regeneration of β‐cell islets in vitro and in vivo. hUC‐MSCs were isolated, cultured, and transfected with lentiviruses for the overexpression of hTIMP‐1. An in vitro coculture system of hUC‐MSCs and streptozotocin‐induced islets was established to examine the morphology, apoptosis, and insulin secretion of the cocultured islets. Diabetic mouse models were injected with lenti‐TIMP‐1‐enhanced green fluorescent protein (EGFP)‐hUC‐MSCs to test the effect of hTIMP‐1 on insulin levels and glucose tolerance in vivo. The expression of insulin and glucagon was evaluated by immunofluorescence staining. The results showed that coculture with hUC‐MSCs or Lenti‐TIMP‐1‐EGFP‐hUC‐MSCs improved islet viability rates. Lenti‐TIMP‐1‐EGFP‐hUC‐MSC coculture increased the insulin and C‐peptide secretion function of the cultured islets and increased the secretion of tumor necrosis factor‐β1, interleukin‐6, IL‐10, and hTIMP‐1. hUC‐MSCs, especially those transfected with Lenti‐hTIMP‐1‐EGFP, showed a strong protective effect in diabetic mice by alleviating weight loss and improving glucose and insulin metabolism. In addition, transplantation rescued islet histology and function in vivo. The overexpression of TIMP‐1 by hUC‐MSCs seems to exert beneficial effects on pancreatic islet cells. In conclusion, this study may provide a new perspective on the development of hUC‐MSC‐based cell transplantation therapy for T1DM. [ABSTRACT FROM AUTHOR]

Red phosphor is indispensable to achieve warm white light in the white light diode (WLED) application. However, the current red phosphors suffer from high cost and harsh synthesis conditions. In this study, an oxide‐based rare‐earth‐free red‐emitting phosphor Li3Mg2NbO6:Mn4+ (LMN:Mn4+) has been successfully synthesized by a simple solid‐state reaction method. The relationship between crystal structure and luminescence was investigated in detail. The site occupancy of the doping Mn4+ ion in the LMN host has been discussed from the point of bond valence sum. How the coordination environment of doping Mn4+ affects the energy level of doping Mn4+ ion has been illustrated via the Tanabe‐Sugano energy‐level diagram. Moreover, warm white light has been obtained using LMN:Mn4+ as compensator to the YAG:Ce3+. [ABSTRACT FROM AUTHOR]

A novel apatite‐based UV‐excited dual‐emitting Ca2Na2La6(SiO4)4(PO4)2O: Eu2+/Eu3+ phosphor (CNL: Eu2+/Eu3+) was designed and successfully synthesized by a solid‐state reaction. Compared with previous reports on this family of materials, a structural study based on DFT calculation exhibited a new consequence that the monovalent ions in this system are more inclined to occupy the seven‐coordinate cationic sites rather than the nine‐coordinate sites. This result was confirmed by the structural refinement and high‐resolution transmission electron microscopy (HRTEM) data. Due to the coexistence of Eu2+ and Eu3+ dopants in the material, under 345 or 392 nm excitation, CNL: 0.02Eu2+/Eu3+ exhibited a green Eu2+ emission band (528 nm) and red Eu3+ emission peaks (around 618 nm). The application potential of CNL:0.02Eu2+/Eu3+ in luminescent thermometry was studied by exploiting the temperature sensitivity of the fluorescent intensity ratio (green/red) at different temperatures. It was found that, under 345 nm excitation, the fluorescent intensity ratio of CNL: 0.02Eu2+/Eu3+ displayed linear correlation over the temperature range of 298 to 473 K with a high sensitivity of 2.82%K−1. Additionally, the emission color of the CNL: 0.02Eu2+/Eu3+ sample under UV lamp (254 and 365 nm) excitation showed an obvious change (from green to red) as the temperature increased from 298 to 473 K (from green to red). These results indicated that CNL: Eu2+/Eu3+ can serve as an excellent visual luminescent ratiometric thermometer. Furthermore, this work provides a novel reference for developing high‐performance luminescence temperature‐sensing materials. [ABSTRACT FROM AUTHOR]

Using the solid-state reaction method, Ce3+, Tb3+-coactivated Si5 AlON7 ( Si6− z Al z O z N8− z, z = 1) phosphors were successfully synthesized. The obtained phosphors exhibit high absorption and strong excitation bands in the wavelength range of 240-440 nm, matching well with the light emitting-diode ( LED) chip. The ET from Ce3+ to Tb3+ ions in Si5 AlON7: Ce3+, Tb3+ has been studied and demonstrated by the luminescence spectra and decay curves. Moreover, the phosphors show tunable emissions from blue to green by tuning the relative ratio of the Ce3+ to Tb3+ ions. Thermal quenching properties of Si5 AlON7: Ce3+, Tb3+ had also been investigated and the quenching temperature is ~190°C. These results show that Si5 AlON7: Ce3+, Tb3+ could be a promising candidate for a single-phased color-tunable phosphor applied in UV-chip pumped LEDs. [ABSTRACT FROM AUTHOR]

Large quantities of hexagonal boron nitride ( h-BN) nanoplates with hexagonal morphologies have been successfully synthesized by a simple two-step route without using any template or catalyst, including combustion synthesis and then annealing processes. The phase content, morphology, and optical properties of the products have been characterized. It reveals that the obtained products are pure and of high crystallinity. The UV-vis absorption spectrum indicates that the h-BN nanoplates have an optical band gap of ~6.07 eV. Strong violet-blue photoluminescence ( PL) emission with a broad band ranging from 400 nm to 475 nm has been observed, indicating that the nanoplates as-grown by this simple route are promising for application in nanosize optical devices ( LEDs, blue-light source, UV detector, etc.). The phonon lines features are obviously found in the PL spectra, the phonon frequency involved in these transitions is consistent with the B-N E2g vibrational mode, which has been measured by the Raman spectroscopy. [ABSTRACT FROM AUTHOR]

Ca12Al14O32Cl2:xBi3+ (0.005 ≤ x ≤ 0.7) phosphors are synthesized by solid state reaction of CaCO3, Al2O3, SiO2, NH4Cl, and Bi2O3 (air, alumina crucible, 1150 °C, 10 h). [ABSTRACT FROM AUTHOR]

The region on chromosome 7q stands out as the region of suggestive linkage to aetiology of autism with the greatest concordance in many independent genome-wide scans. RELN and GRM8, the two genes selected in this study, are located within this region. The protein products of both genes are considered to play a pivotal role in the development of the central nervous system. In addition, biochemical and neuroanatomical data indicated that RELN and GRM8 genes are likely involved in the pathogenesis of autistic disorder. Therefore, both RELN and GRM8 genes are considered to be not only the positional but also the functional candidate genes to autism for association research. In this study, we genotyped 12 single nucleotide polymorphisms (SNPs) located within the RELN and GRM8 genes in 213 children with autistic spectrum disorder (ASD) and 160 controls. A significant genetic association between SNP2 (located in intron 59 of RELN) and ASD was observed, and the log-additive model was accepted as the best inheritance model fitting this data (OR: 0.72, 95% CI: 0.54-0.97, P = 0.03). Haplotype-specific association analysis revealed that the result was consistent with the individual SNP study; the combination of SNP1/SNP2/SNP3/SNP4 which are in strong linkage disequilibrium (LD) (D' > 0.75) showed significant association with ASD (P = 0.027). Neither the single SNP nor the haplotype analysis showed significant association between ASD and the markers of GRM8 gene. Hence, our study suggested the possible involvement of RELN gene in the susceptibility to ASD. Future replications are warranted before definitive conclusion can be drawn., ((c) 2007 Wiley-Liss, Inc.)