Exoskeleton type long-period fiber grating for cross-talk-resistance single-parameter measurement.

This paper proposes a new, to the best of our knowledge, design framework of long-period fiber grating (LPFG) sensors resistant to multi-parameter cross talk. A section of hollow quartz capillary (HQC), which acts as an exoskeleton, is periodically merged with a single-mode fiber (SMF) by the arc-discharge method. The mechanical stress in the SMF is released while the thermal stress is enhanced after a high-temperature fusion process. Under the influence of the elastic-optical effect, the refractive index of the core is periodically modulated along the axial direction to form an exoskeleton long-period fiber grating (Es-LPFG). The unique exoskeleton structure not only induces mode coupling but also enables the proposed device to resist cross talk among the strain, ambient refractive index, and vector bending. The temperature is able to be measured independently with a sensitivity of 74 pm/ ∘C. The novel Es-LPFG is promising in single-parameter sensing, mode-locked lasers, and frequency-locked gain flattening.

Co-linear common-path shearography with a zero-approaching shear amount and separate control of the spatial carrier for single-shot phase measurement.

A co-linear common-path shearography is proposed with spatial phase shift for single-shot phase measurement. The co-linear common-path configuration brings an enhanced robustness and stability of the measuring system, because the two laterally sheared interfering object waves propagate essentially along the same path, which cancels out the disturbance and noise in surroundings. Two functional features, which break through the limitations in conventional co-linear common-path shearography, are proposed and implemented, namely the zero-approaching shear amount and the separate control of the spatial carrier. Seldom shearography configured by co-linear common-path structure possesses with these two features, because the linearly aligned optics restricts the control parameters in regards to the shear amount and the spatial carrier. In the proposed scheme, an intermediate real image plane is created in the linearly aligned light path to address the issue of zero-approaching shear amount. A 4-f imaging system is embedded with an aperture in between to implement a separate control of the spatial carrier. The zero-approaching shear amount provides the sufficiently small shear to make sure the strain or slope field of complex deformation is resolvable. Meanwhile, the separate control of the spatial carrier further guarantees a well-distributed spatial frequency spectrum when the required zero-approaching shear amount is configured.

Super-compact shearography based on a single diffractive optical element with 3-in-1 phase mask.

This Letter communicates a new, to the best of our knowledge, designing framework of shearography. The three elementary functional parts of quantitative shearography, namely imaging, shearing, and phase shifting, are integrated into a single diffractive optical element (DOE), named a 3-in-1 phase mask. The idea breaks through the conventional designing routine of shearography, and converts it from the combination of individual optical elements to the spatial manipulation of phase. The slicing, splicing, and alternating strategy is proposed to generate the 3-in-1 phase mask from a given number of sequenced Fresnel lenses and a modified echelle grating. The operating component is merely a DOE, which renders the optics naturally coaxial. The delivered shearography system enjoys a super-compact configuration, a high level of robustness and stability, and the potential for implementing outside optics laboratories. Crucial system parameters, e.g., shear amount, shear direction, working distance, can be readily shifted on call by re-making the 3-in-1 phase mask. The future of the present idea is in its shape and seems promising with lithography, micromachining, and metasurfaces.

Circular RNA circCSPP1 promotes the occurrence and development of colon cancer by sponging miR-431 and regulating ROCK1 and ZEB1.

BACKGROUND: Colon cancer is a common malignant tumor of the digestive tract, and its incidence is ranked third among gastrointestinal tumors. The present study aims to investigate the role of a novel circular RNA (circCSPP1) in colon cancer and its underlying molecular mechanisms. METHODS: Bioinformatics analysis and reverse transcription-quantitative PCR were used to detect the expression levels of circCSPP1 in colon cancer tissues and cell lines. The effects of circCSPP1 on the behavior of colon cancer cells were investigated using CCK-8, transwell and clonogenic assays. Bioinformatics analysis along with luciferase, fluorescence in situ hybridization and RNA pull-down assays were used to reveal the interaction between circCSPP1, microRNA (miR)-431, Rho associated coiled-coil containing protein kinase 1 (ROCK1) and zinc finger E-box binding homeobox 1 (ZEB1). RESULTS: It was found that circCSPP1 expression was significantly upregulated in colon cancer tissues and cell lines. Overexpression of circCSPP1 significantly promoted the proliferation, migration and invasion of colon cancer cells, whereas silencing of circCSPP1 exerted opposite effects. Mechanistically, circCSPP1 was found to bind with miR-431. In addition, ROCK1 and ZEB1 were identified as the target genes of miR-431. Rescue experiments further confirmed the interaction between circCSPP1, miR-431, ROCK1 and ZEB1. Moreover, circCSPP1 promoted the expression level of ROCK1, cyclin D1, cyclin-dependent kinase 4, ZEB1 and Snail, and lowered the E-cadherin expression level. CONCLUSION: Taken together, the findings of the present study indicated that circCSPP1 may function as a competing endogenous RNA in the progression of colon cancer by regulating the miR-431/ROCK1 and miR-431/ZEB1 signaling axes.

Highly sensitive strain sensor based on a long-period fiber grating with chain-shaped structure.

In this paper, a novel chain-shaped long-period fiber grating (CS-LPFG) for strain measurement is investigated and experimentally demonstrated. This structure is achieved by polishing periodic slant planes on a single-mode fiber with a high-frequency CO2 laser. The chain-shaped structures improved the strain sensitivity of the sensor while shortening the length of the sensing unit. Experimental results show that the strain sensitivity of CS-LPFG is 34.8 pm/µÎµ in the range of 0-650 µÎµ, and the total length of the sensing unit is significantly reduced to 7.5 mm. Meanwhile, the temperature-strain cross talk is 1.6 µÎµ/°C, which is much lower than that of most fiber strain sensors.

All fiber compact bending sensor with high sensitivity based on a multimode fiber embedded chirped long-period grating.

We investigated and prepared a chirped long-period grating for high sensitivity bending measurement. The novel fiber structure is composed of the multimode fiber (MMF) with fixed length and gradually longer single-mode fiber using the continuous splicing method. The powerful ability of refractive index modulation in the MMF renders the miniaturization of the sensor. The total length of the sensor is 3.45 mm. Chirped period arrangement is adopted to improve the bending sensitivity. Through numerical calculation, the chirp coefficient is determined, and the clear resonance peaks are obtained using the wavelength scanning. The experimental results of several samples show that the maximum bending sensitivity is 53.68nm/m-1 at 0-1.803m-1. With the advantages of small size and high sensitivity, the sensor is especially suitable for bending sensing with a micro-structure.

Shear-unlimited common-path speckle interferometer.

A single-aperture common-path speckle interferometer with an unlimited shear amount is developed. This unlimited shear amount is introduced when a Wollaston prism is placed near the Fourier plane of a common-path interferometer, which is built by using a quasi-${4f}$4f imaging system. The fundamentals of the shear amount and the spatial carrier frequency generation are analyzed mathematically, and the theoretical predictions are validated by a static experiment. Mode-I fracture experiments through the three-point bending are conducted to prove the feasibility and the capability of this method in full-field strain measurement with various shear amounts. A remarkable feature of this setup is that no tilt is required between the optical components to produce the unlimited shear amount in off-axis holography.

Chiral Mobile-Phase Additives in HPLC Enantioseparations.

High-performance liquid chromatography (HPLC) is one of the main separation techniques for chiral drugs. Among the chiral HPLC techniques available, the chiral mobile-phase additive (CMPA) technique is a valuable method for the direct enantioseparation of chiral chemical entities. In the CMPA method, the chiral selector is dissolved in the mobile phase while the stationary phase is achiral. Interaction with the analyte enantiomers results in the formation of transient diastereomeric complexes. These complexes differ in their formation constants and/or distribution between the (achiral) stationary phase and the mobile phase resulting in an enantioseparation. This chapter describes the HPLC separation applying CMPA methods by several most useful types of chiral selectors including chiral ligand exchangers, macrocyclic antibiotics, and cyclodextrins.

Non-Contact Roughness Measurement in Sub-Micron Range by Considering Depolarization Effects.

The characteristics of a surface, particularly the roughness, play an important role in different fields of the industry and have to be considered to ensure quality standards. Currently, there are numerous sophisticated methods for measuring surface roughness but plenty of them cause long-term damage because they are in contact with the sample. This article presents a non-contact method to accurately determine small surface roughnesses resulting from the consideration of the depolarization effects caused by the rough surface. This technique can be applied as an extension in various roughness measurements and improves the approach of Chandley's technique, which does not take into account the depolarization of the light scattered by the sample. The experimental setup and the measurements are easy to perform. The essential component is a quarter wave plate, which is incorporated into a Michelson interferometer. With the resulting two different contrasts and the recorded intensities of the sample and the reference mirror, the surface roughness can be estimated straightforwardly. This article details the theoretical approach, followed by the experimental results and the corresponding uncertainties. The experimental results are compared with Chandley's method. In order to have reference roughness values of the samples, measurements with a stylus profilometer and with a confocal microscope are performed and compared.

Real-time dual-sensitive shearography for simultaneous in-plane and out-of-plane strain measurements.

A real-time, dual-sensitive shearography system using a single-wavelength laser was developed for simultaneous and dynamic in-plane and out-of-plane strain measurements. The shearography system is capable of measuring crack-tip deformation fields quantitatively. A spatial multiplexing technique based on Fourier transform is employed for simultaneous and dynamic multi-component phase retrieval. Two slit spatial filters and a common-path shearing interferometer are used to obtain an improved phase quality for crack-tip deformation measurements. Mode-I fracture experiments under three-point bending were conducted to validate the feasibility and the capability of this method.

Dual-directional shearography based on a modified common-path configuration using spatial phase shift.

This paper describes a dual-directional shearography system to address the issue of two-dimensional characterization of the surface strain. A common-path configuration coupled with an additional light path is used to provide the shearing in two directions. One of the three interfering beams is shared by both directional shearograms to improve the light efficiency and enhance the robustness of the system. The two directional shearograms are carried by different spatial carriers to distinguish one from the other. The spatial carrier is introduced by the single-aperture-lens Wollaston prism configuration. Rather than the conventional method in which the aperture is fixed at the front focal point of the imaging lens, a general case is considered by introducing a variable distance between the aperture and the imaging lens. The influence of the aperture-lens distance on the spatial carrier is then analyzed, which enables the separate control of the shearing amount and the spatial carrier. Two types of dual-directional shearography are presented to demonstrate the feasibility and the flexibility of the system. Type I is the simultaneous dual lateral shearography in orthogonal directions, and Type II is the simultaneous lateral and radial shearography. The spatial carrier introduced by the single-aperture-lens Wollaston prism configuration is discussed, and a configuration in which the Wollaston prism and the aperture are located at different sides of the lens is recommended for further shearography applications.

Online 3D Displacement Measurement Using Speckle Interferometer with a Single Illumination-Detection Path.

Measurement systems for online nondestructive full-field three-dimensional (3D) displacement based on the single-shot and multiplexing techniques attract more and more interest, especially throughout the manufacturing industries. This paper proposes an accurate and easy-to-implement method based on an electronic speckle pattern interferometer (ESPI) with single illumination-detection path to realize the online nondestructive full-field 3D displacement measurement. The simple and compact optical system generates three different sensitivity vectors to enable the evaluation of the three orthogonal displacement components. By applying the spatial carrier phase-shifting technique, the desired information can be obtained in real time. The theoretical analysis and the measurement results have proven the feasibility of this ESPI system and quantified its relative measurement error.

Temporal electronic speckle pattern interferometry for real-time in-plane rotation analysis.

A temporal electronic speckle pattern interferometry (ESPI) system is proposed for in-plane rotation measurement. The relationship between the rotation angle and the phase change distribution is established and the rotation direction is indicated by the sign of the partial differential of the phase change distribution. Temporal phase modulation is applied in the proposed symmetric illumination ESPI system. The phase is recovered by the temporal intensity analysis method which uses the temporal evolution history of the light intensity. The system can perform dynamic measurements and provide results in off-line real-time. Preliminary experiments were carried out with a continuously rotating target to show the feasibility and the dynamic feature of the temporal ESPI system. At present, the mean absolute error of the experiment is 0.39 arcsec.

Non-phase unwrapping interferometric approach for a real-time in-plane rotation measurement.

This Letter proposes a novel interferometric approach for the in-plane rotation measurement. With a simple and compact measurement system, the rotation angle and its direction can be determined simultaneously in real time by applying the spatial carrier frequency. Besides, the phase unwrapping process is not required for the angular evaluation, which simplifies the data processing procedure. Theoretically, the relationship between the in-plane rotation and the phase change distribution has been deduced to demonstrate the possibility of this interferometric method. Practically, the preliminary experiments have been carried out to verify the feasibility of this approach and quantify the measurement accuracy.

Simultaneous displacement and slope measurement in electronic speckle pattern interferometry using adjustable aperture multiplexing.

This paper suggests the use of adjustable aperture multiplexing (AAM), a method which is able to introduce multiple tunable carrier frequencies into a three-beam electronic speckle pattern interferometer to measure the out-of-plane displacement and its first-order derivative simultaneously. In the optical arrangement, two single apertures are located in the object and reference light paths, respectively. In cooperation with two adjustable mirrors, virtual images of the single apertures construct three pairs of virtual double apertures with variable aperture opening sizes and aperture distances. By setting the aperture parameter properly, three tunable spatial carrier frequencies are produced within the speckle pattern and completely separate the information of three interferograms in the frequency domain. By applying the inverse Fourier transform to a selected spectrum, its corresponding phase difference distribution can thus be evaluated. Therefore, we can obtain the phase map due to the deformation as well as its slope of the test surface from two speckle patterns which are recorded at different loading events. By this means, simultaneous and dynamic measurements are realized. AAM has greatly simplified the measurement system, which contributes to improving the system stability and increasing the system flexibility and adaptability to various measurement requirements. This paper presents the AAM working principle, the phase retrieval using spatial carrier frequency, and preliminary experimental results.

Bioactive Diterpenoids from Clerodendrum kiangsiense.

A new abeo-abietane diterpenoid, 12-methoxy-6,11,14,16-tetrahydroxy-17(15→16)-abeo-5,8,11,13-abietatetraen-3,7-dione (8), was isolated from the hydroalcoholic extract of the herb of Clerodendrum kiangsiense along with seven known diterpenoids (1-7). Their structures were identified on the basis of spectroscopic analyses including two-dimensional NMR and comparison with literature data. All of these compounds were evaluated for their cytotoxic activities against the growth of human cancer cells lines HL-60, SMMC-7721, A-549 and MCF-7 by the MTT assay. The results showed that cryptojaponol (4), fortunin E (6) and 8 exhibited significant cytotoxicity against four human cancer cell lines.

A new bioactive diterpenoid from pestalotiopsis adusta, an endophytic fungus from clerodendrum canescens.

Bioassay-guided fractionation of the culture extract of Pestalotiopsis adusta, an endophytic fungus isolated from the medicinal plant Clerodendrum canescens, led to the isolation of one new, (10S)-12,16-epoxy-17(15→16)-abeo-3,5,8,12,15-abietapentaen-2,7,11,14-tetraone (1), and four known diterpenoids, teuvincenone F (2), uncinatone (3), coleon U (4), coleon U-12-methyl ether (5). These structures were identified by using spectroscopic methods, including UV, MS, 1D and 2D NMR experiments. This is the first report of these compounds being isolated from a Pestalotiopsis species. The cytotoxic activities of the compounds were evaluated, and compounds 1 and 3 demonstrated cytotoxic activities against the HL-60 tumour cell line (IC50 ï¼œ 20 µM).

A polarized digital shearing speckle pattern interferometry system based on temporal wavelet transformation.

Digital shearing speckle pattern interferometry (DSSPI) has been recognized as a practical tool in testing strain. The DSSPI system which is based on temporal analysis is attractive because of its ability to measure strain dynamically. In this paper, such a DSSPI system with Wollaston prism has been built. The principles and system arrangement are described and the preliminary experimental result of the displacement-derivative test of an aluminum plate is shown with the wavelet transformation method and the Fourier transformation method. The simulations have been conducted with the finite element method. The comparison of the results shows that quantitative measurement of displacement-derivative has been realized.

Continual mechanical vibration trajectory tracking based on electro-optical heterodyne interferometry.

Vibration is one of the confused problems in many fields. To give a comprehensive analysis of vibration, an electro-optical heterodyne interferometry with temporal intensity analysis method that can track the trajectory of the vibration dynamically has been built in this paper. The carrier frequency is introduced by the electrically controlled electro-optical frequency shifter. The trajectory is obtained by using temporal evolution of the light intensity in heterodyne interferometry. The instantaneous displacement of the vibration is extracted with spectral analysis technique. No target mirror and moving parts are required in our self-developed system. The principle and system configuration are described. The simulations and the preliminary experiments have been performed and the results show that this trajectory tracking system is high-efficiency, low-cost, jamproof, robust, precise and simple.

Characterizing the effect of cytochrome P450 (CYP) 2C8, CYP2C9, and CYP2D6 genetic polymorphisms on stereoselective N-demethylation of fluoxetine.

Fluoxetine (FLX) is one of the most widely prescribed selective serotonin reuptake inhibitors. Although FLX is used as racemate in the clinic, the clinical pharmacokinetics of FLX and its N-demethylation metabolite norfluoxetine (NFLX) show obvious cytochrome P450 (CYP) polymorphism dependency and exhibit marked stereoselectivity. However, the kinetic profiles of CYP variants to FLX remain unclear. In the present study, some variants of human CYP2C8, CYP2C9, and CYP2D6 were first expressed in insect cells, and their catalytic roles with respect to FLX enantiomers were then investigated. CYP2C8.4 and CYP2C9.10 showed significantly lower activity and CYP2C8.3 showed significantly higher activity toward both R- and S-FLX compared with the wildtype, while CYP2C9.3, CYP2C9.13, and CYP2C9.16 showed significantly lower activity only toward R-FLX. Five CYP2C9 variants and CYP2D6.1 exhibited significantly stereoselective kinetic profiles prior to R-FLX, and CYP2C8.3 showed a slight stereoselectivity. Interestingly, obvious substrate inhibition was observed in the CYP2C9 wildtype and its three variants only in the case of R-FLX. Together, these findings suggest that CYP2C9 and CYP2D6 polymorphism may play an important role in the clearance of FLX and also in the stereoselective kinetic profiles of FLX enantiomers.