The DNA Repair Enzyme Apurinic/Apyrimidinic Endonuclease (Apex Nuclease) 2 Has the Potential to Protect against Down-Regulation of Chondrocyte Activity in Osteoarthritis

Apurinic/apyrimidinic endonuclease 2 (Apex 2) plays a critical role in DNA repair caused by oxidative damage in a variety of human somatic cells. We speculated that chondrocyte Apex 2 may protect against the catabolic process of articular cartilage in osteoarthritis (OA). Higher levels of Apex 2 expression were histologically observed in severely compared with mildly degenerated OA cartilage from STR/OrtCrlj mice, an experimental model which spontaneously develops OA. The immunopositivity of Apex 2 was significantly correlated with the degree of cartilage degeneration. Moreover, the OA-related catabolic factor interleukin-1β induced the expression of Apex 2 in chondrocytes, while Apex 2 silencing using small interfering RNA reduced chondrocyte activity in vitro. The expression of Apex 2 in chondrocytes therefore appears to be associated with the degeneration of articular cartilage and could be induced by an OA-related catabolic factor to protect against the catabolic process of articular cartilage. Our findings suggest that Apex 2 may have the potential to prevent the catabolic stress-mediated down-regulation of chondrocyte activity in OA.     

Modulation of Interparticle Distance in Discrete Gold Nanoparticle Dimers and Trimers by DNA Single‐Base Pairing

Self‐assembled structures of metallic nanoparticles with dynamically changeable interparticle distance hold promise for the regulation of collective physical properties. This paper describes gold nanoparticle dimers and trimers that exhibit spontaneous and reversible changes in interparticle distance. To exploit this property, a gold nanoparticle is modified with precisely one long DNA strand and approximately five short DNA strands. The long DNA serves to align the nanoparticles on a template DNA via hybridization, while the short DNAs function to induce the interparticle distance changes. The obtained dimer and trimer are characterized with gel electrophoresis, dynamic light scattering measurements, and transmission electron microscopy (TEM). When the complementary short DNA is added to form the fully matched duplexes on the particle surface in the presence of MgCl₂, spontaneous reduction of the interparticle distance is observed with TEM and cryo‐electron microscopy. By contrast, when the terminal‐mismatched DNA is added, no structural change occurs under the same conditions. Therefore, the single base pairing/unpairing at the outermost surface of the nanoparticle impacts the interparticle distance. This unique feature could be applied to the regulation of structures and properties of various DNA‐functionalized nanoparticle assemblies.     

Molecular design of high performance fused heteroacene radical cations: A DFT study

Hybrid density functional theory (DFT) calculations have been carried out for neutral and radical cation of fused furan oligomer, denoted by F(n) where n means number of furan rings in the oligomer, to elucidate the electronic structures at ground and low-lying excited states. A polymer of fused furan was also investigated using one-dimensional periodic boundary condition (PBC) for comparison. It was found that the reorganization energy of radical cation of F(n) from vertical hole trapping point to its relaxed structure is significantly small. Also, the reorganization energy decreased gradually with increasing n, indicating that F(n) has an effective hole transport property. It was found that the cation radical of F(n) has a low energy band at near IR region, which is strongly correlated to hole conductivity. The relation between the electronic states and hole conductivity was discussed on the basis of theoretical calculations.     

An asymptotically optimal fixed-width confidence interval for the difference of two normal means

We consider the problem of providing a fixed width confidence interval for the difference of two normal means when the variances are unknown and unequal. We propose a two-stage procedure that differs from those of Chapman (1950) and Ghosll (1975). The procedure provides the desired confidence, subject to the restriction on the width, for certain values of the design parameter h. Values of h are given by the Monte Carlo rnethod for various combinations of first stage sample size and confidence level. Finally, it is shown that the procedure is asymptotically more efficient than those of Chapmail and Ghosh with respect to total sample size, as the width of the interval approaches zero.     

Verbal working memory and solvent exposure: A positron emission tomography study.

Neuropsychological studies have documented frontal dysfunction in patients with a history of exposure to organic solvents. The deficits typically observed in these patients appear to be related to working memory (WM). This study used [1?O] water positron emission tomography (PET) to examine the pattern of neural activation during verbal working memory in patients with a history of exposure to solvents. Six individuals with solvent exposure were compared with 6 age- and education-matched controls. On the 2 WM tasks examined with PET, with equivalent task performance, participants with solvent exposure demonstrated frontal peaks that were atypical for the tasks, whereas the posterior peaks were typical for the tasks. The results support frontal dysfunction and compensatory use within anterior regions of the WM system in patients with solvent exposure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the computational power of binary decision diagram with redundant variables

We introduce a BDD with redundant variables as an Indexed BDD (IBDD) and define PolyIBDD as the class of Boolean functions represented by polynomial-sized IBDDs for the number of input variables. Assuming that the class of languages on {0, 1}^* that are accepted by logarithmic space bounded DTMs is DLOG, the following relation holds. PolyIBDD = DLOG. That is to say that languages which belong to DLOG also belong to PolyIBDD. We also show examples of polynomial-sized IBDD's construction from logarithmic space bounded DTMs.     

A new index for mapping lichen-dominated biological soil crusts in desert areas

Tracking the presence, distribution and disappearance of biological soil crusts is important for ecosystem management of desert regions and provides highly valuable information on desertification and climate change studies in arid environments. Based on the analysis of the spectral features of biological soil crusts, we propose a new biological soil crust index (BSCI) for biological soil crusts mapping. Using both a radiative transfer simulation and an analysis of a Landsat Enhanced Thematic Mapper Plus (ETM+) image, we examined the ability of satellite remote sensing to detect and map biological soil crusts. Our simulation indicated that Landsat ETM+ data could be used, after atmospheric correction, to detect biological soil crusts if 33% or more of any pixel was accounted for by biological soil crusts. When the proposed BSCI was applied to the detection of biological soil crusts in the Gurbantonggut Desert, Xingjiang, China, a Kappa coefficient of 0.82 and an overall accuracy of 94.7% were achieved. These experimental results indicate that the new index is applicable to identification of lichen-dominated biological soil crusts, and therefore has good potential for biological soil crust detection and mapping in cool and cold deserts.     

New limits to automaticity: Context modulates semantic priming.

It is widely assumed that semantic priming in visual word recognition is automatic when the task requires word-level analysis. The present experiments show that this conclusion is too strong. Whether brief-duration primes facilitated the processing of related targets in lexical decision depended on the context in which the primes were seen. Semantic priming occurred if Ss saw only brief primes (blocked condition) but was minimal if longer primes were presented as well (mixed condition). Converging operations indicate that this modulation of semantic priming reflects operations beyond the lexical level rather than early encoding deficits. Rather than being automatic, semantic priming depends on the context in which a word is read. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Formation and transformation of SrGeO3

The reaction of an equimolar mixture of SrCO₃ and GeO₂ proceeds in five stages, [1]–[5]. The overall reaction of [1], [2], and [3]

$\text{2SrCO}{}_3\text{+}\text{GeO}{}_2\text{→}\text{Sr}{}_2\text{GeO}{}_4\text{+}\text{2CO}{}_2\text{[1]}\text{SrCO}{}_3\text{+}\text{4GeO}{}_2\text{→}\text{SrGe}{}_4\text{O}{}_9\text{+}\text{CO}{}_2\text{[2]}\text{SrCO}{}_3\text{+}\text{GeO}{}_2\text{→}\text{β-SrGeO}{}_3\text{+}\text{CO}{}_2\text{[3]}\text{β-SrGeO}{}_3{}^{\mathrm{<mtext>transformation</mtext>}}\text{α-SrGeO}{}_3\text{[4]}\text{3Sr}{}_2\text{GeO}{}_4\text{+}\text{SrGe}{}_4\text{O}{}_9\text{→7(}\text{α-SrGeO}{}_3\text{)}\text{[5]}$

is best described by the Jander equation, the apparent activation energy being 47.6 kcal mol^?1 irrespective of the ball-milling time. β-Strontium metagermanate is formed directly at lower temperatures from amorphous material prepared by the simultaneous hydrolysis of strontium and germanium alkoxides. Kinetic studies of β-SrGeO₃ formation and β- → α-SrGeO₃ transformation are carried out by means of X-ray diffraction.     

n-3 long-chain FA decrease serum levels of TG and remnant-like particle-cholesterol in humans

A large number of papers have reported that administration of n−3 FA reduced serum TG concentrations in hypertriglyceridemic patients. However, few studies have examined the effect of n−3 FA on serum concentrations of remnant-like particle (RLP) cholesterol. Volunteers (n=41) whose serum TG concentrations were 100–300 mg/dL were recruited and randomly assigned to either an n−3 FA group or a control group with stratification by sex, age, and serum TG level in a double-blind manner. The subjects in the n−3 FA group were administered 125 ml of fermented soybean milk with fish oil containing 600 mg of EPA and 260 mg of DHA/d for 12 wk. The controls consumed control soybean milk with olive oil. Fasting blood samples were obtained before the start of administration and at 4, 8 and 12 wk. EPA concentrations in red blood cells increased significantly in all but one subject in the n−3 FA group, with no significant changes in the control group. TG levels decreased more in the n−3 FA group than in the control group at weeks 4 (P<0.05), 8 (P<0.01), and 12 (P<0.05) with their baseline as covariate. RLP cholesterol levels decreased more in the n−3 FA group than in the control at weeks 8 (P<0.01) and 12 (P<0.05) with their baseline as covariate. The groups did not differ in the other lipid levels. It is likely that n−3 long-chain FA may exert anti-atherosclerotic effects by lowering serum TG and RLP-cholesterol levels even at the dose of 860 mg/d.