钴铬铜复合离子掺杂黑色玻璃的制备及光吸收特性研究

以钠硼硅玻璃为基质,引入过渡金属离子为着色剂制备了单一离子着色玻璃和复合离子掺杂黑色玻璃,测定了各玻璃样品的透射光谱。结果表明,不同过渡金属离子对不同波段的太阳光产生吸收,钴铬铜复合离子掺杂黑色玻璃对到达地表的所有太阳光波段的吸收率可达到99%以上。     

In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against Atrazine

Widespread use of the chlorotriazine herbicide, atrazine, has led to serious environmental and human health consequences. Current methods of detecting atrazine contamination are neither rapid nor cost-effective. In this work, atrazine-specific single-stranded DNA (ssDNA) molecular recognition elements (MRE) were isolated. We utilized a stringent Systematic Evolution of Ligands by Exponential Enrichment (SELEX) methodology that placed the greatest emphasis on what the MRE should not bind to. After twelve rounds of SELEX, an atrazine-specific MRE with high affinity was obtained. The equilibrium dissociation constant (K_d) of the ssDNA sequence is 0.62 ± 0.21 nM. It also has significant selectivity for atrazine over atrazine metabolites and other pesticides found in environmentally similar locations and concentrations. Furthermore, we have detected environmentally relevant atrazine concentrations in river water using this MRE. The strong affinity and selectivity of the selected atrazine-specific ssDNA validated the stringent SELEX methodology and identified a MRE that will be useful for rapid atrazine detection in environmental samples.     

Methanobactin-Mediated Synthesis of Gold Nanoparticles Supported over Al2O3 toward an Efficient Catalyst for Glucose Oxidation

Methanobactin (Mb) is a copper-binding peptide that appears to function as an agent for copper sequestration and uptake in methanotrophs. Mb can also bind and reduce Au(III) to Au(0). In this paper, Au/Al₂O₃ catalysts prepared by a novel incipient wetness-Mb-mediated bioreduction method were used for glucose oxidation. The catalysts were characterized, and the analysis revealed that very small gold nanoparticles with a particle size <4 nm were prepared by the incipient wetness-Mb-mediated bioreduction method, even at 1.0% Au loading (w/w). The influence of Au loading, calcination temperature and calcination time on the specific activity of Au/Al₂O₃ catalysts was systematically investigated. Experimental results showed that decomposing the Mb molecules properly by calcinations can enhance the specific activity of Au/Al₂O₃ catalysts, though they acted as reductant and protective agents during the catalyst preparation. Au/Al₂O₃ catalysts synthesized by the method exhibited optimum specific activity under operational synthesis conditions of Au loading of 1.0 wt % and calcined at 450 °C for 2 h. The catalysts were reused eight times, without a significant decrease in specific activity. To our knowledge, this is the first attempt at the preparation of Au/Al₂O₃ catalysts by Mb-mediated in situ synthesis of gold nanoparticles.     

The lethal giant larvae Gene in Tribolium castaneum: Molecular Properties and Roles in Larval and Pupal Development as Revealed by RNA Interference

We identified and characterized the TcLgl gene putatively encoding lethal giant larvae (Lgl) protein from the red flour beetle (Tribolium castaneum). Analyses of developmental stage and tissue-specific expression patterns revealed that TcLgl was constitutively expressed. To examine the role of TcLgl in insect development, RNA interference was performed in early (1-day) larvae, late (20-day) larvae, and early (1-day) pupae. The early larvae injected with double-stranded RNA of TcLgl (dsTcLgl) at 100, 200, and 400 ng/larva failed to pupate, and 100% mortality was achieved within 20 days after the injection or before the pupation. The late larvae injected with dsTcLgl at these doses reduced the pupation rates to only 50.3%, 36.0%, and 18.2%, respectively. The un-pupated larvae gradually died after one week, and visually unaffected pupae failed to emerge into adults and died during the pupal stage. Similarly, when early pupae were injected with dsTcLgl at these doses, the normal eclosion rates were reduced to only 22.5%, 18.0%, and 11.2%, respectively, on day 7 after the injection, and all the adults with abnormal eclosion died in two days after the eclosion. These results indicate that TcLgl plays an essential role in insect development, especially during their metamorphosis.     

Protective Effect of Resveratrol against IL-1β-Induced Inflammatory Response on Human Osteoarthritic Chondrocytes Partly via the TLR4/MyD88/NF-κB Signaling Pathway: An “in Vitro Study”

Resveratrol is a natural polyphenolic compound that prevents inflammation in chondrocytes and animal models of osteoarthritis (OA) via yet to be defined mechanisms. The purpose of this study was to determine whether the protective effect of resveratrol on IL-1β-induced human articular chondrocytes was associated with the TLR4/MyD88/NF-κB signaling pathway by incubating human articular chondrocytes (harvested from osteoarthritis patients) with IL-1β before treatment with resveratrol. Cell viability was evaluated using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and TNFα levels in culture supernatants were measured by ELISA(Enzymelinked immunosorbent assay). The levels of TLR4 and its downstream signaling targets (MyD88 and TRAF6) and IL-1β were assessed by measuring the levels of mRNA and protein expression by real-time RT-PCR and western blot analysis, respectively, in addition to assessing NF-κB activation. In addition, TLR4 siRNA was used to block TLR4 expression in chondrocytes further demonstrating that resveratrol prevented IL-1β-mediated inflammation by TLR4 inhibition. We found that resveratrol prevented IL-1β-induced reduction in cell viability. Stimulation of chondrocytes with IL-1β caused a significant up-regulation of TLR4 and its downstream targets MyD88 and TRAF6 resulting in NF-κB activation associated with the synthesis of IL-1β and TNFα. These IL-1β-induced inflammatory responses were all effectively reversed by resveratrol. Furthermore, activation of NF-κB in chondrocytes treated with TLR4 siRNA was significantly attenuated, but not abolished, and exposure to resveratrol further reduced NF-κB translocation. These data suggested that resveratrol prevented IL-1β-induced inflammation in human articular chondrocytes at least in part by inhibiting the TLR4/MyD88/NF-κB signaling pathway suggesting that resveratrol has the potential to be used as a nutritional supplement to counteract OA symptoms.     

Doublecortin May Play a Role in Defining Chondrocyte Phenotype

Embryonic development of articular cartilage has not been well understood and the role of doublecortin (DCX) in determination of chondrocyte phenotype is unknown. Here, we use a DCX promoter-driven eGFP reporter mouse model to study the dynamic gene expression profiles in mouse embryonic handplates at E12.5 to E13.5 when the condensed mesenchymal cells differentiate into either endochondral chondrocytes or joint interzone cells. Illumina microarray analysis identified a variety of genes that were expressed differentially in the different regions of mouse handplate. The unique expression patterns of many genes were revealed. Cytl1 and 3110032G18RIK were highly expressed in the proximal region of E12.5 handplate and the carpal region of E13.5 handplate, whereas Olfr538, Kctd15, and Cited1 were highly expressed in the distal region of E12.5 and the metacarpal region of E13.5 handplates. There was an increasing gradient of Hrc expression in the proximal to distal direction in E13.5 handplate. Furthermore, when human DCX protein was expressed in human adipose stem cells, collagen II was decreased while aggrecan, matrilin 2, and GDF5 were increased during the 14-day pellet culture. These findings suggest that DCX may play a role in defining chondrocyte phenotype.     

Autophagic Cell Death and Cancer

Programmed cell death (PCD) is a crucial process required for the normal development and physiology of metazoans. The three major mechanisms that induce PCD are called type I (apoptosis), type II (autophagic cell death), and type III (necrotic cell death). Dysfunctional PCD leads to diseases such as cancer and neurodegeneration. Although apoptosis is the most common form of PCD, recent studies have provided evidence that there are other forms of cell death. One of such cell death is autophagic cell death, which occurs via the activation of autophagy. The present review summarizes recent knowledge about autophagic cell death and discusses the relationship with tumorigenesis.     

Stem Cell Treatment for Alzheimer’s Disease

Alzheimer’s disease (AD) is a progressive and neurodegenerative disorder that induces dementia in older people. It was first reported in 1907 by Alois Alzheimer, who characterized the disease as causing memory loss and cognitive impairment. Pathologic characteristics of AD are β-amyloid plaques, neurofibrillary tangles and neurodegeneration. Current therapies only target the relief of symptoms using various drugs, and do not cure the disease. Recently, stem cell therapy has been shown to be a potential approach to various diseases, including neurodegenerative disorders, and in this review, we focus on stem cell therapies for AD.