All Fiber-optic Fluorescent Spectral Measurement and Analysis on Alga Chla/c Characteristics

The fluorescent principle used for measuring alga characteristic parameters and the optimum structure design of the instrument are discussed. The fluorescent spectrum of Chla/c and the time-resolved different spectrum ΔA(λ,t) are given. The research provides an effective method for considering the density and the classification of algae, which will be helpful to monitor sea pollution.

Temperature and light tolerance of representative brown,green and red algae in tumble culture revealed by chlorophyll fluorescence measurements

Laminaria japonica, Undaria pinnatifida, Ulva lactuca, Grateloupia turuturu and Palmaria palmata are suitable species that fit the requirements of a seaweed-animal integrated aquaculture system in terms of their viable biomass, rapid growth and promising nutrient uptake rates. In this investigation, the responses of the optimal chlorophyll fluorescence yield of the five algal species in tumble culture were assessed at a temperature range of 10 - 30℃. The results revealed that Ulva lactuca was the most resistant species to high temperature, withstanding 30℃ for 4 h without apparent decline in the optimal chlorophyll fluorescence yield . While the arctic alga Palmaria palmata was the most vulnerable one, showing significant decline in the optimal chlorophyll fluorescence yield at 25℃ for 2 h. The cold-water species Laminaria japonica, however, demonstrated strong ability to cope with higher temperature （24 -26℃ ） for shorter time （within 24 h） without significant decline in the optimal chlorophyll fluorescence yield . Grateloupia turuturu showed a general decrease in the optimal chlorophyll fluorescence yield with the rising temperature from 23 to 30℃ , similar to the temperate kelp Undaria pinnatifida. Changes of chlorophyll fluorescence yields of these algae were characterized differently indicating the existence of species-unique strategy to cope with high light. Measurements of the optimal chlorophyll fluorescence yield after short exposure to direct solar irradiance revealed how long these exposures could be without significant photoinhibition or with promising recovery in photosynthetic activities. Seasonal pattern of alternation of algal species in tank culture in the Northern Hemisphere at the latitude of 36°N was proposed according to these basic measurements.

Quantitative measurement and application of droplets on physical surfaces based on LIF technology

Contaminated surfaces play a significant role in the transmission of respiratory infectious diseases.To address this issue,we pre-sented a novel quantitative detection method for droplets on physical surfaces,based on the laser-induced fluorescence technique.The proposed detection method was demonstrated in a realistic high-speed train compartment scenario by simulating the process of droplet release during passengers’breathing and coughing.The experimental results showed that this method could offer high precision(10-1 mg/m^(2))for detecting minute substance concentrations,and its ease of operation makes it suitable for complex en-gineering environments.The results also revealed that under the combined effects of the indoor airflow and breathing airflow,the range of droplets released by breathing activity exceeded two rows in front of and behind the release position.Simultaneously,we observed that a large number of droplets settled on the seat surfaces on both sides of the same row as the releaser,with over 36%of these droplets concentrated on the backrest area of the seats.As the respiratory jet velocity increased,the location with the most sed-iment droplets(accounting for 8%of the total sedimentation)occurred on the seat directly in front of the releaser,and approximately 48% of the droplets were found on the back of this seat.Our proposed method overcomes the shortcomings of existing experimental methods in quantitatively capturing the motion characteristics of droplets in complex flow fields.

Citrate-stabilized CdSe/CdS quantum dots as fluorescence probe for protein determination

A rapid, ultrasensitive and convenient fluorescence measurement technology based on the enhancement of the fluorescence intensity resulting from the interaction of functionalized CdSe/CdS quantum dots （QDs） with bov/ne serum albumin （BSA） was proposed. The citrate-stabilized CdSe/CdS （QDs） were synthesized by using Se powder and Na2S as precursors instead of any pyrophoric organometallic precursors. The modified CdSe/CdS QDs are brighter and more stable against photobleaching in comparison with organic fluorophores. At pH 7.0, the fluorescence signal of CdSe/CdS is enhanced by increasing the concentration of BSA in the range of 0.1-10 μg/mL, and the low detection limit is 0.06 μg/mL. A linear relationship between the enhanced fluorescence peak intensity （△F） and BSA concentration （c） is established using equation △F=50.7c＋16.4 （R=0.996 36）. Results of determination for BSA in three synthetic samples are identical with the true values, and the recovery （98.9%-102.4%） and relative standard deviation （RSD, 1.8%-2.5%） are satisfactory.

Novel Portable Oil Ingredient Instrument with Optical Fiber Link

The operation principle of a novel portable oil ingredient instrument is introduced. Using the theory of fluorescence measurement, this instrument can carry out fast and consecutive in-situ detection of oil ingredient in sea water, confirming fast and correctly the situation of oil contamination such as the concentration and the area, etc. The lowest detectable concentration for the instrument is 1×10 -8 g/ml with the precision of less than 3 %. The results of experiment and practice show that this system has well water-sealed characteristic and repeatability.

Microfluidic chip enables single-cell measurement for multidrug resistance in triple-negative breast cancer cells

Aims:Triple-negative breast cancer patients are commonly treated with combination chemotherapy.Nonetheless,outcomes remain substandard with relapses being of a frequent occurrence.Among the several mechanisms that result in treatment failure,multidrug resistance,which is mediated by ATP-binding cassette proteins,is the most common.Regardless of the substantial studies conducted on the heterogeneity of cancer types,only a few assays can distinguish the variability in multidrug resistance activity between individual cells.We aim to develop a single-cell assay to study this.Methods:This experiment utilized a microfluidic chip to measure the drug accumulation in single breast cancer cells in order to understand the inhibition of drug efflux properties.Results:Selection of single cells,loading of drugs,and fluorescence measurement for intracellular drug accumulation were all conducted on a microfluidic chip.As a result,measurements of the accumulation of chemotherapeutic drugs(e.g.,daunorubicin and paclitaxel)in single cells in the presence and absence of cyclosporine A were conducted.Parameters such as initial drug accumulation,signal saturation time,and fold-increase of drug with and without the presence cyclosporine A were also tested.Conclusion:The results display that drug accumulation in a single-cell greatly enhanced over its same-cell control because of inhibition by cyclosporine A.Furthermore,this experiment may provide a platform for future liquid biopsy studies to characterize the multidrug resistance activity at a single-cell level.

Detection of Staphylococcus Aureus using quantum dots as fluorescence labels

Staphylococcus aureus(S.aureus)has been identified as one of the major foodborne pathogenic bacteria.The development of rapid detection methods for S.aureus is needed for assuring food safety.In this study,quantum dots were used as fluorescent labels in an immunoassay for quantitative detection of S.aureus.Firstly,biotin-labeled anti-S.aureus antibody was conjugated with streptavidin-coated magnetic nanobeads(180 nm diameter)and used to separate S.aureus cells.Then streptavidin coated quantum dots(QDs)were conjugated with biotin-labeled anti-S.aureus antibody and used as the fluorescence labels to mix with the separated S.aureus.Finally the fluorescence intensity of the bead-cell-QD complexes was measured at a wavelength of 620 nm.A linear relationship between S.aureus cell number(X)and fluorescence intensity(Y)was found for cell numbers ranging from 10^(3) to 10^(6) CFU(Colony Forming Unit)/mL,and the detection limit was 10^(3) CFU/mL.The regression model can be expressed as Y=7.68X+35.06 with R^(2)=0.94.The detection of S.aureus in food sample was explored initially.The fluorescence intensity of food sample was close to the background,so it was not satisfied.Further study will focus on the application of the method for detection of S.aureus in food sample.