A detection method of typical toxic mixed red tide algae in Qinhuangdao based on three-dimensional fluorescence spectroscopy.

Red tides occur every year in the Qinhuangdao sea area of China, including a variety of toxic algae and non-toxic algae. Toxic red tide algae have caused great damage to the marine aquaculture industry in China and seriously endangered human health, but most of non-toxic algae are important bait for marine plankton. Therefore, it is very important to identify the type of mixed red tide algae in Qinhuangdao sea area. In this paper, three-dimensional fluorescence spectroscopy and chemometrics were applied to the identification of typical toxic mixed red tide algae in Qinhuangdao. Firstly, the three-dimensional fluorescence spectrum data of typical mixed red tide algae in Qinhuangdao sea area were measured by f-7000 fluorescence spectrometer, and the contour map of algae samples was obtained. Secondly, the contour spectrum analysis is carried out to find the excitation wavelength of the peak position of the three-dimensional fluorescence spectrum and form the new three-dimensional fluorescence spectrum data selected by the feature interval. Then, the new three-dimensional fluorescence spectrum data are extracted by principal component analysis (PCA). Finally, the feature extraction data and the data without feature extraction are used as the input of the genetic optimization support vector machine (GA-SVM) and particle swarm optimization support vector machine (PSO-SVM) classification models, respectively, to obtain the classification model of mixed red tide algae, and the two feature extraction analysis methods and two classification algorithms are compared. The results show that the classification accuracy of the test set using the principal component feature extraction and GA-SVM classification method is 92.97 %, when the excitation wavelengths are 420 nm, 440 nm, 480 nm, 500 nm and 580 nm, and the emission wavelengths are 650-750 nm. Therefore, it is feasible and effective to apply the three-dimensional fluorescence spectrum characteristics and genetic optimization support vector machine classification method to the identification of toxic mixed red tide algae in Qinhuangdao sea area.

[Effect of Different Cationic Polyacrylamide Organic Dehydrating Agents on Sludge Dewatering Performance].

To study the effect of different cationic polyacrylamide organic dehydrating agents on sludge dewatering performance, eight commercially available cationic polyacrylamides of the same series with different properties were used. Based on the different cationic degree, they were named 9101, 9102, 9103, 9104, 9106, 9108, 9110, and 9112, respectively. Their properties were characterized by instruments and chemical analysis, and the indexes of sludge after treatment were also measured. The results showed that the properties of the eight organic dehydrants were different, among which the charge density, cationicity, viscosity, and Zeta potential had homologous trends, which all increased gradually from 9101 to 9112. The four indexes of 9112 were as high as 2.98 meq·L-1, 17.42%, 85.07 mPa·s, and 67.10 mV, respectively. The dewatering performance of sludge was improved by improving the specific resistance of filtration (SRF), floc properties, viscosity, Zeta potential, the bound water content, and the distribution of extracellular polymeric substances (EPS) after dosing organic dewatering agents. The results showed that the viscosity, charge density, cationic degree, and Zeta potential of the dewatering agents had a great influence on the sludge dewatering performance. The SRF of sludge was negatively correlated with the viscosity of the organic dewatering agent, and the correlation coefficient was as high as 0.92025, indicating that the sludge dewatering performance was improved mainly through the adsorption bridging effect of the organic dewatering agent in sludge dewatering.

Large-area mid-infrared broadband absorbers based on spiral ITO resulting from the combination of two different broadening absorption methods.

A large-area mid-infrared broadband absorber is proposed in this paper. The absorber is a spiral ITO structure grown on a hexagonal lattice arrangement of silicon nanopillars by using a glancing angle deposition method. The experimental results show that when the heights of the silicon nanopillars are 1.7 µm and the number of rotation depositions is n = 5, that is, the rotation angle is 150 degrees, the absorber absorbs more than 81% of electromagnetic waves in the 2.5-6 µm spectral range. In the atmospheric window of 3-5 µm, the integral absorption reaches 96%. The experimental results also show that the absorbing ability of the ITO structure in the mid-infrared atmospheric window is significantly stronger than that of the structure composed of silver under the same preparation conditions. The main reasons for the broadband absorption are that the spiral ITO structure has resonant absorption of electromagnetic waves with different wavelengths in the empty cavity regions with different sizes, and ITO has longer penetration depths than noble metals in the mid-infrared band, which brings about stronger broadband absorption. The combination of the two leads to a broadening of the total absorption spectrum. The higher heights of the silicon nanopillars enhance absorption further. Additionally, the loose spiral ITO distributions indicate lower mean plasma concentration and then increase penetration depths further, resulting in stronger light absorption. Such a large-area mid-infrared absorption structure with a simple preparation method has potential applications in mid-infrared cloaking and sensing.

Could lengthening minocycline therapy better treat early syphilis?

Syphilis is a sexually transmitted disease caused by Treponema pallidum. Minocycline, a representative tetracycline derivative, has the greatest antimicrobial activity among all tetracyclines. There are few reports about treating syphilis with minocycline because there is a lack of efficacy data from controlled trials. We compared the rates of serological cure in patients with early syphilis who were treated with minocycline or benzathine penicillin G (BPG).During the study period, a total of 40 syphilis patients received the BPG treatment, which was a single intramuscular dose of 2.4 million units of BPG, and 156 patients were treated with minocycline; 77 patients were placed in the 2-week, standard minocycline therapy group and received 100 mg of minocycline orally, twice daily for 14 days, and 79 patients were placed in the 4-week, lengthened minocycline therapy group and received 100 mg of minocycline orally, twice daily for 28 days. The outcome of interest was the rate of serological cure in these patients.At the end of the 2-year follow-up, the serological cure rate of the 4-week, lengthened minocycline therapy group (87.34%) was higher than that of both the 2-week, standard minocycline therapy group (72.73%) and the BPG treatment group (77.50%). In addition, the curative effect of the 4-week, lengthened minocycline therapy was significantly greater than that of the 2-week, standard minocycline therapy in patients who were aged >40 years; exhibited an initial rapid plasma reagin titer ≥1: 32; or exhibited secondary syphilis (P = 0.000, 0.008, 0.000; <0.05).Minocycline appears to be an effective agent for treating early syphilis, especially when applied as a 4-week, lengthened therapy.

[Design and implementation of command system for emergency events of parasitic diseases].

Based on the requirement analysis and functional design of the command system for parasitic disease outbreaks, the system was constructed by workflow technique, function modules and technical architecture. The command system was a multi-platform system, could achieve multiple functions, such as monitoring and early warning of parasitic diseases, emergency video communication, emergency dispatcher, and emergency management. The system can meet the needs in emergency events of parasitic diseases, and increase preparedness level.

[Study on the interaction of cobalt (II) polyamidomine dendrimer with DNA by spectrometry techniques].

Cobalt (II) polyamidomine dendrimer was prepared by the reaction of cobalt chloride, glyoxal and polyamidomine dendrimer of 5.0 generation. The interaction of cobalt (II) polyamidomine dendrimer complex with herring sperm (hsDNA) was carried out using methylene blue (MB) as the probe molecule by absorption and fluorescence spectroscopy and synchronous fluorescence spectroscopy. The results showed that the intensity of absorption peaks and fluorescence peaks increased when the complex interacted with hsDNA. The effect of sodium chloride showed that sodium ion can significantly constrain the interaction of cobalt(II) polyamidomine dendrimer with hsDNA. The curves indicated the competitive inhibition of MB binding to hsDNA in the presence of cobalt (II) polyamidomine dendrimer complexes, also MB could insert into interior of cobalt (II) polyamidomine dendrimer complexes. The results suggested that the complex mainly interacted with negatively charged phosphate moieties on hsDNA through electrostatic attraction and stacked on the surface of double stranded hsDNA, which may reduce the binding affinity of MB to hsDNA in the surrounding site. It was indicated that sodium ion might neutralize the negatively charged phosphate backbone of hsDNA, and then weaken the electrostatic attraction between complexes and hsDNA.

[A method of recognizing biology surface spectrum using cascade-connection artificial neural nets].

A method of recognizing the visible spectrum of micro-areas on the biological surface with cascade-connection artificial neural nets is presented in the present paper. The visible spectra of spots on apples' pericarp, ranging from 500 to 730 nm, were obtained with a fiber-probe spectrometer, and a new spectrum recognition system consisting of three-level cascade-connection neural nets was set up. The experiments show that the spectra of rotten, scar and bumped spot on an apple's pericarp can be recognized by the spectrum recognition system, and the recognition accuracy is higher than 85% even when noise level is 15%. The new recognition system overcomes the disadvantages of poor accuracy and poor anti-noise with the traditional system based on single cascade neural nets. Finally, a new method of expression of recognition results was proved. The method is based on the conception of degree of membership in fuzzing mathematics, and through it the recognition results can be expressed exactly and objectively.

[Study on the method to adjust optical fiber's spectrum attenuation with the Fourier transform].

A method based on Fourier transform to compensate the non-linear attenuation of optical fiber used as a probe in a spectrum-collecting system was proposed. First the output electric currents of photoelectric tube with and without fiber were transformed to the frequency field. So an adjustable function in frequency field was obtained, and the adjustable function was transformed to the spectrum field, so the final adjustable function was obtained. A photoelectric system was designed for testing. With visible light, this method can make the error rate of fiber transmission as low as less than 1.54%. It is proved that the method is fit for adjusting some optical fiber spectrum attenuation.

[The effect of adjusting the ANN's parameters on the identifying of biology spectrum].

A method to identify the visible spectrum of micro areas on the biological surface with artificial neural net (BP-ANN) was introduced in this paper. The visible spectra (from 500 nm to 730 nm) of the micro areas with some rotten or scars on the surface of the apples were measured with fiber sensor spectrometer. A kind of ANN with a single hidden layer was created to identify the characters on the surface automatically. The effects of different ranges of output, different training functions, different number of single hidden layers, and different noise levels on the ANN were also studied.