- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Simultaneous determination of proteins in microstructured optical fibers supported by chemometric tools
摘要： A new perspective on the relevant problem—creating simple, rapid, and efficient protein sensors based on microstructured optical fibers using a simple homogeneous analysis format—was proposed. Commercially available long-period grating hollow core microstructured optical fibers (LPG HCMOF) were used to determine bovine serum albumin (BSA) and albumin from chicken eggs (OVA) in binary mixtures as well as immunoglobulin G (IgG) in the presence of BSA and OVA. LPG HCMOF transmission spectra allowed the detection of both BSA and OVA up to 10 mg/mL with LOD as low as 0.1 and 0.8 μg/mL, respectively. Partial least squares regression (PLS) was utilized for modeling of LPG HCMOF spectral data and quantitative analysis of BSA, OVA, total protein, and IgG in binary and ternary mixtures. Rather high coefficients of determination (R2) and low root mean square error for the calibration (RMSEC) (15%) and prediction (RMSEP) (20%) were obtained for all PLS models. The proposed approach was tested in the analysis of BSA in spiked horse blood hemolyzed (HBH). The results demonstrated the functionality of the proposed approach and offered the opportunity for the creation of a wide range of sensors for protein determination in complex mixtures.
关键词： Chemometrics,Partial least squares regression,Protein determination,Long-period grating fiber,Microstructured optical fibers
更新于2025-09-16 10:30:52
-
In-process determination of fiber orientation for layer accurate laser ablation of CFRP
摘要： Complex repair geometries including stepped laser ablation of damaged areas in CFRP parts significantly increase the bonding strength of the reconstruction patch. In the optimum case the steps in the repair geometry exactly fit the fiber layers. Unfortunately, the layer thickness is subject to manufacturing related fluctuations. Therefore, the step heights have to be adapted for each layer. To meet these requirements a controlled laser ablation process using optical coherence tomography (OCT) for optical distance measurement was developed, allowing to control the ablation depth with an accuracy of <10 μm. Furthermore, the 2D-Fourier transform of the reconstructed surface topography shows that certain wavelengths only appear perpendicular to the fiber direction, which enables the determination of the fiber orientation. OCT-controlled ablation together with the determination of the fiber direction was used to demonstrate layer accurate repair geometries.
关键词： controlled ablation,layer accurate,CFRP repairing,determination of fiber orientation
更新于2025-09-12 10:27:22
-
Experimental determination of material model of machine parts produced by Selective laser sintering (SLS) technology
摘要： The machine parts realized by additive production technologies are more and more frequently used as parts of machines. To achieve this an exact design process must be carried out, which in general is possible by numerical analysis. To fulfill correct calculation the material properties must be known. Earlier investigations pointed out that the orthotropic material model is suitable to describe the behavior of the model under external loads produced by additive technology. Analysis of this fact, and the material properties of this kind of materials have been investigated in this paper. The results of SLS technology have been compared with the results of other technologies.
关键词： material properties,material law,Additive manufacturing,SLS,experimental determination
更新于2025-09-12 10:27:22
-
Nanoscale temperature measurement during temperature controlled in situ TEM using Al plasmon nanothermometry
摘要： Over recent years, the advent of microelectromechanical system (MEMS)-type microheaters has pushed the limits of temperature controlled in situ transmission electron microscopy (TEM). In particular, by enabling the observation of the structure of materials in their application environments, temperature controlled TEM provides unprecedented insights into the link between the properties of materials and their structure in real-world problems, a clear knowledge of which is necessary for rational development of functional materials with new or improved properties. While temperature is the key parameter in such experiments, accessing the precise temperature of the sample at the nanoscale during observations still remains challenging. In the present work, we have applied aluminium plasmon nanothermometry technique that monitors the temperature dependence of the volume plasmon of Al nanospheres using electron energy loss spectroscopy for in situ local temperature determination over a MEMS microheater. With access to local temperatures between room temperature to 550°C, we have assessed the spatial and temporal stabilities of the microheater when it operates at different setpoint temperatures both under vacuum and in the presence of a static H2 gas environment. Temperature comparisons performed under the two environments show discrepancies between local and setpoint temperatures.
关键词： in situ transmission electron microscopy,electron energy loss spectroscopy,volume expansion of metal,local temperature determination,volume plasmons shift
更新于2025-09-12 10:27:22
-
Study on the preparation of water-soluble AgInS2 quantum dots and their application in the detection of ciprofloxacin
摘要： Water-soluble AgInS2 quantum dots (AIS QDs) were prepared by hot-injection method with thioglycolic acid (TGA) as the stabilizer. The fluorescence of as-prepared AIS QDs could be quenched effectively by ciprofloxacin. Herein, a method for the content determination of ciprofloxacin based on the fluorescence quenching effect was explored. The experimental results showed that the particle size of AIS QDs prepared at pH = 4 was about 3–8 nm, and the maximum fluorescence emission wavelength was centered at 626 nm at λex = 500 nm. The measured concentration range of ciprofloxacin could be adjusted by varying the amount of AIS QDs solution. When 0.40 mL AIS QDs solution was used for the content determination of ciprofloxacin, a good linearity relationship was achieved between the quenched efficiency of AIS QDs fluorescence and the concentration of ciprofloxacin in the range of 1.0–19.5 μg/mL, the correlation coefficient was 0.996, the detection limit of ciprofloxacin was 0.12 μg/mL, and the blank spike recoveries were in the range of 96.7–103.3%. The method is of wide detection range, excellent selectivity, high sensitivity and easy operability, could be applied for the content determination of ciprofloxacin in drugs.
关键词： AgInS2 quantum dots,Ciprofloxacin,Fluorescence quenching,Content determination
更新于2025-09-12 10:27:22
-
Direct Observation of Chain Lengths and Conformations in Oligofluorene Distributions from Controlled Polymerization by Double Electron–Electron Resonance
摘要： Synthetic polymers are mixtures of chains with different lengths, and their chain length and chain conformation is often experimentally characterized by ensemble averages. We demonstrate that Double-Electron-Electron-Resonance (DEER) spectroscopy can reveal the chain length distribution, and chain conformation and flexibility of the individual n-mers in oligo-(9,9-dioctylfluorene) from controlled Suzuki-Miyaura Coupling Polymerization (cSMCP). The required spin-labeled chain ends were introduced efficiently via a TEMPO-substituted initiator and chain terminating agent, respectively, with an in situ catalyst system. Individual precise chain length oligomers as reference materials were obtained by a stepwise approach. Chain length distribution, chain conformation and flexibility can also be accessed within poly(fluorene) nanoparticles.
关键词： controlled polymerization,polymer particles,wormlike chain model,conjugated polymers,Electron paramagnetic resonance,double-Electron-Electron resonance (DEER),distance determination
更新于2025-09-12 10:27:22
-
[IEEE 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - Torino, Italy (2019.6.19-2019.6.21)] 2019 IEEE 5th International Workshop on Metrology for AeroSpace (MetroAeroSpace) - LED-based attitude reconstruction and back-up light communication: experimental applications for the LEDSAT CubeSat
摘要： Optical observations are intensively applied to space debris monitoring for the achievement of orbit determination and for gathering information on their attitude motion, even if constrained by light conditions. Light Emitting Diodes (LEDs) installed on the external surfaces of a satellite could increase the visibility interval to the whole eclipse time. LEDSAT (LED-based small SATellite) is a 1-Unit CubeSat aimed at demonstrating the effectiveness of LEDs for the improvement of space debris optical monitoring algorithms. The LEDSAT experimental mode includes flashing patterns that will allow the CubeSat attitude reconstruction and the testing of a back-up light-based communication method. This paper will describe the features of the LEDSAT experimental mode, by describing the needed measurements for achieving the satellite LED-based attitude reconstruction and the features of the back-up LED communication.
关键词： orbit determination,attitude reconstruction,CubeSat,space debris,LED,light communication
更新于2025-09-11 14:15:04
-
A Simple and Rapid Staining Technique for Sex Determination of Trichinella Larvae Parasites by Confocal Laser Scanning Microscopy
摘要： The roundworms of Trichinella genus are worldwide distributed and their prevalence in nature is high. Trichinella genus parasites are the causative agents of foodborne zoonosis trichinellosis. The main prevention and control of the infection are meat inspection by the magnetic stirrer method for the detection of Trichinella larvae in muscle samples. The treatment can be effective if the parasite is discovered early in the intestinal phase. Once the Trichinella larva has reached the muscle tissue, the parasite remains therein and there is no treatment for this life cycle stage. The Trichinella species is dioecious with separate male and female individuals. The developed staining technique that uses confocal laser scanning microscopy (CLSM) displays sufficient results for Trichinella larvae examination and this protocol is applicable to study the internal and external structures and for the sex determination of T. britovi and T. spiralis larvae samples. In the present study, a luminescent derivative was synthesized and used for staining of T. spiralis and T. britovi larvae samples for the examination by CLSM. Various fixatives, such as AFA, 70% ethanol, and Bouin’s and Carnoy’s solutions were tested for sample preparation. The synthesized luminescent compound demonstrates best visualization results for samples fixed in Bouin’s fixative.
关键词： benzanthrone dye,fixatives,confocal laser scanning microscopy,Trichinella larvae sex determination,Bouin’s fixative
更新于2025-09-11 14:15:04
-
Analysis of Laser Ranges and Angular Measurements Data Fusion for Space Debris Orbit Determination
摘要： In the framework of space debris, the orbit determination process is a fundamental step, both, for researchers and for satellite operators. The accurate knowledge of the orbit of space debris objects is needed to allow space debris characterization studies and to avoid unnecessary collision avoidance maneuvers. The accuracy of the results of an orbit determination process depends on several factors as the number, the accuracy, the kind of processed measurements, their distribution along the orbit, and the object-observer relative geometry. When the observation coverage of the target orbit is not homogeneous, the accuracy of the orbit determination can be improved processing di?erent kind of observables. Recent studies showed that the satellite laser ranging technique can be successfully applied to space debris. In this paper, we will investigate the bene?ts of using laser ranges and angular measurements for the orbit determination process. We will analyze the in?uence of the number of used observations, of the covered arc of orbit, of each observable, and of the observation geometry on the estimated parameters. Finally, using data acquired on short observation arcs, we analyze the achievable accuracies for the orbital regimes with the highest space debris density, and to the consequences of the data fusion on catalog maintenance operations. The results shown are obtained using only real data (both angular and laser measurements) provided by sensors of the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald owned by the Astronomical Institute of the University of Bern (AIUB) and for some studies also using ranges provided from other stations of the International Laser Ranging Service (ILRS).
关键词： orbit determination,real range measurements,data fusion,real angular measurements,accuracy improvements,space debris
更新于2025-09-11 14:15:04
-
Joint activity and attenuation estimation for PET with TOF data and single events
摘要： Maximum likelihood reconstruction of activity and attenuation (MLAA) for PET data with time-of-flight (TOF) information can determine the activity distribution up to a scale, and the attenuation map Radon transform up to a related constant. Prior knowledge is widely used for the determination of the constant. However, prior knowledge could be inaccurate due to patient variation and may result in quantitation errors. Our goal is to develop a method that can determine the scale and the related constant in the TOF-MLAA algorithm to obtain quantitatively accurate activity and attenuation maps. Our idea is to utilize the single events which have depth dependent attenuation factors, contrary to coincidence events. We show that in a 2D case, with the combination of TOF information and single events, a unique solution of attenuation and activity can be achieved. A three-step iterative image reconstruction algorithm is developed. In each iteration, the activity distribution is first updated using the MLEM approach with TOF PET data; the attenuation map is then updated using MLTR with non-TOF data; finally, both activity distribution and attenuation map are updated using a scale estimated from single events. Noisy and noise-free projection data are generated for 2D XCAT phantoms through analytical simulation. Both scatter information and randoms information are assumed to be known. The proposed method and the conventional TOF-MLAA algorithm are used to reconstruct the simulated data. Conventional MLEM method with known attenuation map is implemented for comparison as well. Normalized root mean square error (NRMSE) and optimal constant are defined for the quantitative analysis of reconstructed images. Our proposed image reconstruction method achieves ~1% NRMSE for the activity map and ~5% NRMSE for the attenuation map with a correct scale after 150 iterations for noise-free data. Results of noisy simulations are consistent with noise-free data. In summary, we have proposed to use the single events for constant determination in TOF-MLAA algorithm to obtain a unique solution of attenuation map and activity distribution without prior information. Future work will be dedicated to the extension of our method to the 3D situation.
关键词： constant determination,single events,attenuation correction
更新于2025-09-10 09:29:36