Efficient nitrogen-vacancy centers' fluorescence excitation and collection from micrometer-sized diamond by a tapered optical fiber

Efficiently excite nitrogen-vacancy (NV) centers in diamond and collect their fluorescence significantly benefit the fiber-optic-based NV sensors. Here, using a tapered optical fiber (TOF) tip, we significantly improve the efficiency of the laser excitation and fluorescence collection of the NV, thus enhance the sensitivity of the fiber-optic based micron-sized diamond magnetic sensor. Numerical calculation shows that the TOF tip delivers a high numerical aperture (NA) and has a high fluorescence excitation and collection efficiency. Experiments demonstrate that using such TOF tip can obtain up to over 7-fold the fluorescence excitation efficiency and over15-fold the fluorescence collection efficiency of a flat-ended (non-TOF) fiber. Such fluorescence collection enhances the sensitivity of the optical fiber-based diamond NV magnetometer, thus extending its potential application region.Comment: 11 pages, 13 figure

Distributions of surface sediments surrounding the Antarctic Peninsula and its environmental significance

We analyzed grain size composition to provide information on the types and distributions as well as depositional varieties of marine surface sediments from the area surrounding the Antarctic Peninsula. The samples retrieved from the study area contain gravel, sand, silt and clay. As suggested by bathymetry and morphology, the study area is characterized by neritic, hemipelagic and pelagic deposits. The glacial-marine sediments can be divided into two types, residual paratill and compound paratill, which are primarily transported by glaciers and as ice-rafted debris. Ocean current effects on deposition are more obvious, and the deposit types are distributed consistently with terrain variations

Experimental Study on Influence of Combustion Bed Catalytic Thickness on Resistance Characteristics of Fuel-air Mixture

AbstractFuel-air mixture is a typical of flammable and explosive material and tens of thousands of cubic meters of oil steam and air mixture will be presented in the ventilation and replacement project at any time, no matter in the anti-explosion of ventilation operation in the oil tank, or in the anti-explosion of fuel-air mixture in emergency. Thermo-catalytic combusting technology used in the anti-explosion of fuel-air mixture is viewed as a kind of most promising technology, which can safely dispose the fuel-air mixture. This paper mainly introduces the resistance characteristics of fuel-air mixture within the catalytic combustion bed and the experimental results of the influence of catalytic thickness on resistance of fuel-air mixture. Based on the experiment and analysis, the resistance predicting model using in catalytic combusting bed is putting forward. The conclusions drown from the studies and researches will not only have much important significance for the design and optimization with thermo-catalytic reactor for anti-explosion in oil and natural gas engineering, but also supply some important references to the analysis of the fuel-air mixture flowing in porous media in other fields

Kriging Interpolation for Evaluating the Mineral Resources of Cobalt-Rich Crusts on Magellan Seamounts

The evaluation of mineral resources on seamounts by geostatistics faces two key challenges. First, the conventional distance/orientation- and the simple distance-based variogram functions used are ineffective at expressing the spatial self-correlation and continuity of cobalt-rich crust thicknesses on seamounts. Second, the sampling stations used for a single seamount are generally very sparsely distributed because of the high survey costs, which results in an insufficient number of information points for variogram fitting. Here, we present an alternative geostatistical method that uses distance/gradient- and distance/relative-depth-based variograms to process data collected from several neighboring seamounts, allowing the variogram fitting. The application example reported for the Magellan seamounts demonstrates the suitability of the method for evaluating the mineral resources of cobalt-rich crusts. The method could be effective also for the analysis of surface data obtained from mountain slopes on land (e.g., soil)

Baicalein alleviates depression-like behavior in rotenone- induced Parkinson's disease model in mice through activating the BDNF/TrkB/CREB pathway

Background: Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder in the world. In addition to motor symptoms, a variety of non-motor symptoms seriously affect the life quality of PD patients. Baicalein, a flavonoid extracted from the herb Scutellaria baicalensis Georgi, exhibits anti-PD activity through alleviation of its motor symptoms. However, its effects on non-motor symptoms were barely reported. This study aimed to investigate the therapeutic effects of baicalein on PD-related depression. Methods: After a 2-week injection of rotenone, mice with PD-related depression behavior were selected, divided into three groups, and administrated saline, baicalein, or madopar orally for four weeks. Behavior, neuroinflammation, neurotransmitters, and synaptic plasticity were evaluated. Results: Our results showed that 4-week baicalein treatment significantly alleviated the depression-like behavior in the rotenone-induced mice model. Repeated baicalein treatment reduced α-synuclein aggregation, inhibited neuroinflammation, and maintained neurotransmitters homeostasis. Moreover, we found that baicalein treatment could remarkably protect the synaptic plasticity and activate the BDNF/TrkB/CREB pathway in the PD-related depression mice model. As traditional dopamine replacement therapy unleashed few effects on depression-like symptom amelioration and synaptic function protection, baicalein might be a more appropriate choice for PD-related depression. Conclusions: The current results suggested that baicalein could act as a treatment for PD-related depression

Preclinical detection of porcine circovirus type 2 infection using an ultrasensitive nanoparticle DNA probe-based PCR assay.

Porcine circovirus type 2 (PCV2) has emerged as one of the most important pathogens affecting swine production globally. Preclinical identification of PCV2 is very important for effective prophylaxis of PCV2-associated diseases. In this study, we developed an ultrasensitive nanoparticle DNA probe-based PCR assay (UNDP-PCR) for PCV2 detection. Magnetic microparticles coated with PCV2 specific DNA probes were used to enrich PCV2 DNA from samples, then gold nanoparticles coated with PCV2 specific oligonucleotides were added to form a sandwich nucleic acid-complex. After the complex was formed, the oligonucleotides were released and characterized by PCR. This assay exhibited about 500-fold more sensitive than conventional PCR, with a detection limit of 2 copies of purified PCV2 genomic DNA and 10 viral copies of PCV2 in serum. The assay has a wide detection range for all of PCV2 genotypes with reliable reproducibility. No cross-reactivity was observed from the samples of other related viruses including porcine circovirus type 1, porcine parvovirus, porcine pseudorabies virus, porcine reproductive and respiratory syndrome virus and classical swine fever virus. The positive detection rate of PCV2 specific UNDP-PCR in 40 preclinical field samples was 27.5%, which appeared greater than that by conventional and real-time PCR and appeared application potency in evaluation of the viral loads levels of preclinical infection samples. The UNDP-PCR assay reported here can reliably rule out false negative results from antibody-based assays, provide a nucleic acid extraction free, specific, ultrasensitive, economic and rapid diagnosis method for preclinical PCV2 infection in field, which may help prevent large-scale outbreaks