Computational fluid dynamics (CFD) investigation of impacts of an obstruction on airflow in underground mines

Continuous airflow monitoring can improve the safety of the underground work force by ensuring the uninterrupted and controlled distribution of mine ventilation to all working areas. Air velocity measurements vary significantly and can change rapidly depending on the exact measurement location and, in particular, due to the presence of obstructions in the air stream. Air velocity must be measured at locations away from obstructions to avoid the vortices and eddies that can produce inaccurate readings. Further, an uninterrupted measurement path cannot always be guaranteed when using continuous airflow monitors due to the presence of nearby equipment, personnel, roof falls and rib rolls. Effective use of these devices requires selection of a minimum distance from an obstacle, such that an air velocity measurement can be made but not affected by the presence of that obstacle. This paper investigates the impacts of an obstruction on the behavior of downstream airflow using a numerical CFD model calibrated with experimental test results from underground testing. Factors including entry size, obstruction size and the inlet or incident velocity are examined for their effects on the distributions of airflow around an obstruction. A relationship is developed between the minimum measurement distance and the hydraulic diameters of the entry and the obstruction. A final analysis considers the impacts of continuous monitor location on the accuracy of velocity measurements and on the application of minimum measurement distance guidelines.

Low-Dose Azithromycin Attenuates OVA-Induced Airway Remodeling and Inflammation via Down-Regulating TGF-βl Expression in RAT

Asthma is characteristic with chronic airway inflammation and remodeling. Azithromycin (AZM), the 15-member macrolide, is known to present an anti-inflammatory effect and is increasingly being used in the treatment of chronic inflammatory pulmonary diseases. We hypothesize that low-dose azithromycin can inhibit allergen-induced airway remodeling except allergic airway inflammation in rat model. Male SD rats underwent intraperitoneal ovalbumin sensitization on days 1 and 6 followed by an intranasal challenge on day 7–13. On day 14, airway inflammation and remodeling were assessed by quantifying leukocytes in the airway, expression of multiple inflammatory mediators in BALF, histological examination in lung and TGF-β1 mRNA and protein levels by qRT-PCR, immunohistochemistry and Western blotting. Treatment with low-dose azithromycin at the dose of 25 mg/kg significantly reduced ovalbumin-dependent airway inflammation, including accumulation of neutrophils, lymphocytes and eosinophils, secretion of IL-2, IL-4, IL-13 and TNF-α. Moreover, airway remodeling was significantly abrogated by azithromycin in this model. The mucus cell hyperplasia, thickening of the peribronchial smooth muscle layer, secretion of ET-1, IL-2, IL-4, IL-13 and TNF-α, and increasing mRNA and protein expressions of TGF-β1 in lung tissue were all significantly decreased in azithromycin-treated rats. These findings demonstrate the protective effect of low-dose azithromycin on allergic airway remodeling in rat and suggest low-dose azithromycin may have beneficial effects in treating allergic airway inflammation.

Nanostructured Si-nanowire microarrays for enhanced-performance bio-analytics

We demonstrate the fabrication of a novel platform based on Si nanowire arrays integrated with a programmable DNA-directed homogeneous-phase analyte-capture strategy for robust detection of bio-analytes. The nanofabrication process used, based on a combination of glancing-angle-deposition and metal-assisted-catalytic-etching, is capable of producing thousands of testing sites per chip, and the sites can be fabricated over entire wafers, with precise control of size and positioning, using conventional microelectronics technology. The analyte-capture strategy used eliminates the well-known interference of the heterogeneous-phase (substrate) with the capturing of analytes. We examine the effects of the nanoscale features of the substrates (nanowire porosity and clumping) on the coupling efficiency of analytes and show that the fabricated microarrays are robust, have high efficiency and capacity, and provide significantly enhanced signal-to-noise ratio detection.

Protective effect of puerarin against beta-amyloid-induced oxidative stress in neuronal cultures from rat hippocampus: involvement of the GSK-3β/Nrf2 signaling pathway

Current evidence suggests that amyloid beta (Aβ) peptides may play a major role in the pathogenesis of Alzheimer's disease in part by eliciting oxidative stress. Puerarin, a major isoflavone glycoside from Kudzu root (Pueraria lobata), has been reported to exert estrogen-like and antioxidant activities. The central hypothesis guiding this study is that puerarin will prevent or at least markedly attenuate Aβ(25-35)-induced excess production of reactive oxygen species (ROS) by interrupting glycogen synthase kinase-3β (GSK-3β) signaling. In this study, we demonstrate that pretreatment of primary hippocampal neurons with puerarin significantly reduced Aβ(25-35)-induced oxidative stress characterized by scavenging of ROS and inhibiting lipid peroxidation. Puerarin induced expression of nuclear Nrf2 protein, but not in the Nrf2 mRNA level, and increased heme oxygenase-1 (HO-1) levels at levels of transcription and translation. Puerarin-induced Serine 9 phosphorylation of GSK-3β was blocked by lithium chloride treatment in primary hippocampal neurons, indicating the participation of the GSK-3β inactivation. This protective effect was partially reversed when GSK-3β were blocked by the chemical inhibitors such as lithium chloride. These results suggest puerarin as a phytoestrogen with potential of a possible therapeutic agent in neurodegenerative diseases involving oxidative stress.

Evidence for the direct two-photon transition from ψ(3686) to J/ψ

The two-photon transition ψ(3686)→γγJ/ψ is studied in a sample of 1.06×10(8) ψ(3686) decays collected by the BESIII detector. The branching fraction is measured to be (3.1±0.6(stat)(-1.0)(+0.8)(syst))×10(-4) using J/ψ→e(+)e(-) and J/ψ→μ(+)μ(-) decays, and its upper limit is estimated to be 4.5×10(-4) at the 90% confidence level. This work represents the first measurement of a two-photon transition among charmonium states. The orientation of the ψ(3686) decay plane and the J/ψ polarization in this decay are also studied. In addition, the product branching fractions of sequential E1 transitions ψ(3686)→γχ(cJ) and χ(cJ)→γJ/ψ(J=0,1,2) are reported.

Effects of probiotic, Clostridium butyricum, on growth performance, immune function, and cecal microflora in broiler chickens

Four hundred and fifty 1-d-old male Lingnan Yellow broiler chickens were used to investigate the effects of Clostridium butyricum on growth performance, immune function, and cecal microflora. The birds were randomly assigned to 5 treatments and offered the same antibiotic-free basal diets for 42 d. The treatments were as follows: no addition (control), 1 × 10(7) cfu C. butyricum/kg of diet (CB1), 2 × 10(7) cfu C. butyricum/kg of diet (CB2), 3 × 10(7) cfu C. butyricum/kg of diet (CB3), and 10 mg of colistine sulfate/kg of diet (antibiotic). Birds fed either CB2 or antibiotic had greater overall BW than those in the control group. During d 1 to 7, d 21 to 42, and d 1 to 42, birds fed either CB2 or CB3 or the antibiotic diet had greater ADG compared with those in the control group. No significant differences were observed in BW or ADG among the CB2, CB3, and antibiotic groups. Birds fed the CB2 or CB3 diet had greater concentrations of IgA and IgG in the serum from d 14 to 42 and greater IgM in the serum from d 21 to 42 than those in the control group. Birds fed the CB3 diet had a greater concentration of complement component 3 in the serum than those in the control group from d 7 to 42. Dietary C. butyricum decreased (P < 0.05) Escherichia coli in cecal contents on d 14 and 42, and both CB2 and CB3 decreased (P < 0.05) cecal Salmonella and Clostridium perfringen from d 14 to 42 compared with the control. Broilers fed either CB2 or CB3 had greater cecal Lactobacillus and Bifidobacterium counts from d 21 to 42, and birds fed C. butyricum had greater cecal C. butyricum counts during the whole period compared with those in the control group. The results indicate that C. butyricum promotes growth performance and immune function and benefits the balance of the intestinal microflora in broiler chickens.

Increased expression of a novel splice variant of the complement component 4 (C4A) gene in mastitis-infected dairy cattle

The complement system helps in the direct lysis of invading pathogens and modulates phagocytic, humoral and cellular immune responses. Complement 4 is a critical component in complement activity and protection against many bacterial pathogens because it is essential to classical and lectin activation pathways. We used reverse transcription and PCR to investigate alternative splicing and expression of the complement component 4 (C4A) gene in Chinese Holstein cattle. The PCR products were cloned and sequenced. A novel splice variant involving intron 10 was identified, which we named C4A-AS. To examine how C4A gene activity is affected by bovine mastitis, six Chinese Holstein cattle were divided into healthy (non-mastitic) and Staphylococcus aureus-induced mastitic groups. Real-time quantitative PCR (qRT-PCR) revealed that the C4A-complete and C4A-AS transcripts are expressed at significantly different levels in healthy cows, while there were no significant differences in the mastitic group (P = 0.257). Expression of C4A-AS increased significantly when mastitis developed. We also examined the expression of C4A-complete and C4A-AS in several tissues (liver, heart, spleen, lung, kidney, tongue, and muscle). The two transcripts were expressed in all of these tissues but there were no significant differences in expression between healthy and mastitic cows. We therefore conclude that the C4A-complete transcript is the main transcript under normal physiological conditions, while C4A-AS is augmented when mastitis develops.

First observation of the M1 transition ψ(3686)→γη(c)(2S)

Using a sample of 106×10(6) ψ(3686) events collected with the BESIII detector at the BEPCII storage ring, we have made the first measurement of the M1 transition between the radially excited charmonium S-wave spin-triplet and the radially excited S-wave spin-singlet states: ψ(3686)→γη(c)(2S). Analyses of the processes ψ(3686)→γη(c)(2S) with η(c)(2S)→K(S)(0)K(±)π(∓) and K(+)K(-)π(0) give an η(c)(2S) signal with a statistical significance of greater than 10 standard deviations under a wide range of assumptions about the signal and background properties. The data are used to obtain measurements of the η(c)(2S) mass (M(η(c)(2S))=3637.6±2.9(stat)±1.6(syst) MeV/c(2)), width (Γ(η(c)(2S))=16.9±6.4(stat)±4.8(syst) MeV), and the product branching-fraction (B(ψ(3686)→γη(c)(2S))×B(η(c)(2S)→KKπ)=(1.30±0.20(stat)±0.30(syst))×10(-5)). Combining our result with a BABAR measurement of B(η(c)(2S)→KKπ), we find the branching fraction of the M1 transition to be B(ψ(3686)→γη(c)(2S))=(6.8±1.1(stat)±4.5(syst))×10(-4).