Chaos-assisted broadband momentum transformation in optical microresonators

The law of momentum conservation rules out many desired processes in optical microresonators. We report broadband momentum transformations of light in asymmetric whispering gallery microresonators. Assisted by chaotic motions, broadband light can travel between optical modes with different angular momenta within a few picoseconds. Efficient coupling from visible to near-infrared bands is demonstrated between a nanowaveguide and whispering gallery modes with quality factors exceeding 10 million. The broadband momentum transformation enhances the device conversion efficiency of the third-harmonic generation by greater than three orders of magnitude over the conventional evanescent-wave coupling. The observed broadband and fast momentum transformation could promote applications such as multicolor lasers, broadband memories, and multiwavelength optical networks

Effects of TGF- β

Introduction. This study aimed to explore the effects of TGF-β1 on regulating activities of cementoblasts and osteoblasts with or without stress. Material and Methods. Human recombinant TGF-β1 was added with different doses. Immunohistochemical test of osteoprotegerin (OPG)/receptor activator of nuclear factor-kappaB ligand (RANKL) and Alizarin Red-S staining were conducted. Mechanical compressive stress was obtained by increasing the pressure of gaseous phase. OPG/RANKL expression was detected in both cells through quantitative real-time PCR. Results. Similar significant differences (P<0.05) existed in OPG/RANKL change with increasing concentration of TGF-β1 without mechanical stress for cementoblasts and osteoblasts. However, under 3 h stress, OPG increased and RANKL decreased significantly (P<0.01) but with similar OPG/RANKL change. Moreover, under 24 h stress, OPG change exhibited no difference (P>0.05), but RANKL decreased significantly (P<0.01) at 10 and 100 ng/mL TGF-β1 in cementoblasts. In osteoblasts, OPG increased significantly (P<0.01) at 10 and 100 ng/mL, whereas RANKL decreased with statistical difference (P<0.05) at 1 and 10 ng/mL. Conclusions. The effects of TGF-β1 on OPG/RANKL expression of cementoblasts and osteoblasts are similar even without mechanical stress. However, these effects are different under mechanical compressive stress

A novel procedure for precise quantification of Schistosoma japonicum eggs in bovine feces

Schistosomiasis japonica is a zoonosis with a number of mammalian species acting as reservoir hosts, including water buffaloes which can contribute up to 75% to human transmission in the People's Republic of China. Determining prevalence and intensity of Schistosoma japonicum in mammalian hosts is important for calculating transmission rates and determining environmental contamination. A new procedure, the formalin-ethyl acetate sedimentation-digestion (FEA-SD) technique, for increased visualization of S. japonicum eggs in bovine feces, is described that is an effective technique for identifying and quantifying S. japonicum eggs in fecal samples from naturally infected Chinese water buffaloes and from carabao (water buffalo) in the Philippines. The procedure involves filtration, sedimentation, potassium hydroxide digestion and centrifugation steps prior to microscopy. Bulk debris, including the dense cellulosic material present in bovine feces, often obscures schistosome eggs with the result that prevalence and infection intensity based on direct visualization cannot be made accurately. This technique removes nearly 70% of debris from the fecal samples and renders the remaining debris translucent. It allows improved microscopic visualization of S. japonicum eggs and provides an accurate quantitative method for the estimation of infection in bovines and other ruminant reservoir hosts. We show that the FEA-SD technique could be of considerable value if applied as a surveillance tool for animal reservoirs of S. japonicum, particularly in areas with low to high infection intensity, or where, following control efforts, there is suspected elimination of schistosomiasis japonica.This work was partially supported by the following grants: The National High Technology Research and Development Program of China (grant No. 2007AA02Z153), and National Science and Technology Major Program (grant Nos. 2009ZX10004-302, 2008ZX10004-011)

Antibacterial Activity and Mode of Action of Mentha arvensis Ethanol Extract against Multidrug-Resistant Acinetobacter baumannii

Purpose: To evaluate the antibacterial effect of ethanol extract of Mentha arvensis against multi-drug resistant Acinetobacter baumannii using liquid chromatography–mass spectrometry (LC-ESI-MS).Methods: Disc diffusion and microdilution assays were used to evaluate the antibacterial effect of the extract by measuring the zone of inhibition, minimum inhibitory concentration (MIC) and and minimum bacteriocidal concentration (MBC) of the extract against the test bacteria. Scanning electron microscopy (SEM) was employed to evaluate the morphological changes induced by the extract in cellular membrane of the bacteria. Reactive oxygen species (ROS) generation and protein leakage from the bacterial cells induced by the extract were also evaluated.Results: The extract showed dose-dependent growth inhibitory effects against A. baumannii with MIC and MBC of 23.5 and 72.1 μg/mL, respectively. The extract also induced potent ROS generation and protein leakage in A. baumannii bacterial cells. SEM findings revealed that the extract induced potential cellular damage which increased with increasing extract concentration.Conclusion: The ethanol extract of Mentha arvensis is a potent antibacterial agent against A. baumannii and acts by inducing lethal cellular damage to the bacterium.Keywords: Mentha arvensis, Acinetobacter baumannii, Reactive oxygen species, Antibacterial activity, Cellular membrane damag

Chaos-assisted broadband momentum transformation in optical microresonators

The law of momentum conservation rules out many desired processes in optical microresonators. We report broadband momentum transformations of light in asymmetric whispering gallery microresonators. Assisted by chaotic motions, broadband light can travel between optical modes with different angular momenta within a few picoseconds. Efficient coupling from visible to near-infrared bands is demonstrated between a nanowaveguide and whispering gallery modes with quality factors exceeding 10 million. The broadband momentum transformation enhances the device conversion efficiency of the third-harmonic generation by greater than three orders of magnitude over the conventional evanescent-wave coupling. The observed broadband and fast momentum transformation could promote applications such as multicolor lasers, broadband memories, and multiwavelength optical networks