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A flexible and detachable gas-absorption cell with variable optical path length was designed to obtain the optical path optimal length for gas detection based on ultraviolet differential optical absorption spectroscopy. A model of the gas-absorption cell structure was established based on Lambert-Beer law. This model demonstrates the effect of different optical path lengths on ammonia detection, and the optical path optimal length of the proposed system is 1.6 m. A gas detection system was developed with the proposed gas-absorption cell, and the feasibility and stability of the system were evaluated at different ammonia concentrations. Owing to the influence of light loss induced by spherical concave mirror reflection and ammonia absorption, the detection results for ammonia at a concentration of 17 ppm are more accurate when the optical path length is 1.6 m versus 0.8 and 2.4 m. The error is less than 0.6% that is consistent with the simulation results. When the optical path length is 1.6 m, the linearity between the detection and the standard values reaches 0.9993. The standard deviation of the detection results is less than 0.3 ppm, indicating good stability of the system. The minimum detection limit of 0.43 ppm per meter is achieved. Water has a slight influence on the results of ammonia concentration detection. When the relative humidity is 7.5%, the response time of the system is 120 s that becomes longer with the increase of relative humidity. This method can be used to detect other gases with high precision.

In this letter, we demonstrate a high-sensitivity flow rate sensor which is packaged using a stable and convenient method. The sensor is based on an optofluidic microbottle resonator (OFMBR), which serves as a promising platform for fluid sensing due to its ultrahigh quality factor and inherent microfluidic channel. The coupling system is packaged using a modified method, and the sensor’s stability is verified using phosphate buffered saline at different flow rates. According to the Bernoulli effect of fluid, the dynamic change of velocity in OFMBR can be detected via wavelength shift mechanism of whispering galley mode. Both the simulated and experimental results show that sensitivity can be enhanced for a given wall thickness by exploiting higher order radial modes of the OFMBR. The maximum sensitivity of 0.079 pm/( $\mu \text{L}$ /min) within the range of 0- $200~\mu \text{L}$ /min is achieved in the experiment. This sensor provides an optional method for fluid detection with high sensitivity and stability.

We demonstrate a high-sensitivity bidirectional magnetic field sensor based on a packaged optofluidic microbottle resonator (OFMBR) filled with magnetic fluid (MF). The relationship between sensitivity and different wall thicknesses and radial modes of OFMBR is theoretically analyzed. Then the thin-wall OFMBR is fabricated by etching a capillary with the fusion discharge process. The OFMBR and tapered fiber is packaged with a portable and robust coupling configuration. By applying perpendicular or parallel magnetic field directions to the OFMBR, opposite refractive index responses of the MF can be obtained, with resonant wavelengths redshifted or blueshifted as the magnetic field intensity is increased. A magnetic field sensitivity of 98.23 pm/mT can be obtained by using the second-order radial mode when the magnetic field is perpendicular to the packaged OFMBR. When the magnetic field is parallel to the packaged OFMBR, the sensitivity is −304.80 pm/mT by using the third-order radial mode and the detection limit reaches 0.0656 mT. The proposed sensor has the advantages of easy fabrication, high sensitivity, and reliability, showing a great potential in bidirectional magnetic field application.

Abatract Miniature inverted-repeat transposable elements (MITEs) are a group of DNA transposable element (TE) which preferentially distributed with gene associated regions. Tens of MITEs families have been revealed in Brassica napus genome, they scatter across the genome with tens of thousands copies and produce polymorphisms both intra- and inter-species. Our previous studies revealed a Tourist-like MITE, Monkey King, associated with vernalization requirement of B. napus, however there are still few studies reveal MITE association with agricultural traits in B. napus. In the present study, 80 polymorphic markers were developed from 55 MITEs, and used to evaluate genetic diversity in a panel of B. napus accessions consisting of 101 natural and 25 synthetic genotypes. Five agricultural traits, oil content, glucosinolate content, erucic acid content, weight of thousand seeds (WTS) and plant height, were investigated across 3-years field experiments, in addition, two traits, hypocotyl length and root length, were evaluated at the 4-leaf stage in the laboratory. Correlations between the MITE-based markers and seven traits were analyzed, finally, 10 polymorphic markers produced by 6 pairs of MITE specific primers were revealed relatively high correlation with 5 traits. Two polymorphic markers were anchored with two candidate genes, BnaA02g13530D and BnaA08g20010D, respectively, which may contribute to glucosinolate content and WTS. This research may contribute to genetic improvement through utilization of MITE-induced polymorphisms in Brassica species.

In this work, bismuth doped fiber (BDF) and bismuth/phosphosilicate co-doped fiber (BPDF) were fabricated by atomic layer deposition (ALD) combined with the modified chemical vapor deposition (MCVD). The spectral characteristics are studied experimentally and the BPDF has good excitation effect covering the O band. A diode pumped BPDF amplifier with the gain over 20 dB from 1298-1348 nm (50 nm) has been demonstrated. The maximum gain of 30 dB was measured at 1320 nm with a gain coefficient of around 0.5 dB/m. Furthermore, we constructed different local structures through simulation and found that compared with the BDF, BPDF has a stronger excited state and a greater significance in O-band. This is mainly because phosphorus (P) doping changes the associated electron distribution and forms the bismuth-phosphorus active center. The fiber has a high gain coefficient, which is of great significance for the industrialization of O-band fiber amplifier.

The magneto-refractive properties of Er/Yb co-doped silica fiber (EYDF) are important in magnetic field sensing. Here, we proposed a theoretical calculation model of the EYDF using density functional theory (DFT) and demonstrated it by an interferometric digital hologram magneto-refractive measurement system. The calculation results show that the fiber material, doped with Er/Yb atoms, has a large net spin and asymmetric spin distribution, which enables the elements to play an important role in the magnetic characteristics of the material. The experimental results show that the refractive index of the fiber decreases linearly with the increase of the magnetic field. The sensitivity of EYDF is 3.8279 × 10-5 RIU/Gs and is two orders of magnitude higher than that of single-mode fiber which is confirmed by the theoretical calculation. It demonstrated that the EYDF has advantages and potential of high sensitivity, miniaturization, and easy integration for magnetic field detection in harsh environments.

We report a magnetic field sensor based on an optofluidic microbottle resonator (OFMBR) with whispering gallery mode (WGM) strongly confined in the axial direction, with the hollow core inherently easy to infiltrate the magnetic fluid. The device is simply fabricated along a silica capillary through a fusing splicer. And the influence of number of discharges on the size of the device is analyzed according to the state equation of ideal gas, which is verified by experimental results. In the magnetic field range from the critical value (40 Gs) to the saturated value (300 Gs), the resonant wavelength shifts linearly with the increase of magnetic field strength, with a sensitivity of 8.45 pm/Gs demonstrated, based on the axial confined mode of OFMBR with a Q-factor of 1.28 × 106. This sensor possesses advantages of simple structure, easy fabrication process, and compact size for magnetic field sensing.

A novel PbS/PbSe co-doped fiber is fabricated by the modified chemical vapor deposition (MCVD) technology. Its absorption and luminescence characteristics are investigated. There are two absorption peaks at 773 and 1161 nm, respectively. The luminescence spectrum ranges from 1000 to 1350 nm. In addition, the intensity of luminescence is related to pump power.

The magneto-refractive characteristics of erbium-doped silica fiber (EDF) are of great significance in magnetic field sensing. The fiber doped with rare earth Er3+ has a large magnetic moment and spin splitting, which makes a major contribution to the magnetic properties of the fiber. The refractive index of EDF in different magnetic fields was measured. The experimental results show that the refractive index of EDF decreases linearly with the increase of magnetic field. The magneto-refractive sensitivity of EDF is 3.21×10−5 RI /mT, which is about 20 times higher than that of single-mode fiber. The magneto-refractive properties of silica fiber are enhanced by rare earth element Er3+.

We designed C+L band light sources with Bi/Er/La co-doped silica fibers. The broadband one had fluorescence intensity of −21.00 dBm in 1527–1612 nm, and the different-wavelength lasers were generated.

The spectral and gain characteristics of Bi/Er codoped silica optical fiber are investigated in this paper. The fiber provides four obvious absorption peaks, which result from the energy level transitions of Er3+ and Bi iron. The fiber exhibits ultra-broadband luminescence spectrum region between 1100 and 1700 nm when pumped by 980 nm laser. And the maximum gain of the fiber can reach 34 dB at 1534 nm when the pump power is 131.3 mW. Those prove that this fiber is conducive to the application of laser and amplifier.

We demonstrate a novel fiber Bragg grating (FBG) temperature sensor based on lead sulfide (PbS)-doped silica optical fiber, prepared by atomic layer deposition (ALD) doping technique. The FBGs are fabricated using the phase mask method, without hydrogen loading. The temperature sensitivity of the FBG-PbS is found to be $\sim$ 19 pm/ $^\circ$ C within 20–150 $^\circ$ C, showing great linearity and repeatability. It is increased by approximately 60% compared to the temperature sensitivity of FBG in standard single mode fiber (SMF). Furthermore, the temperature characteristics of PbS-doped silica optical fiber are investigated. The thermal expansion coefficient and thermal-optic coefficient of PbS-doped silica fiber are 6.3 $\times\; 10^{-7}$ and 1.23 $\times\; 10^{-5}$ / $^\circ$ C, respectively. Moreover, the thermal-optic coefficient value of the PbS-doped silica optical fiber is nearly one order of magnitude higher than that of SMF. Therefore, the FBG based on PbS-doped silica optical fiber appears to be very attractive for the temperature sensing fields.

The efficient identification of bacteria is of considerable significance in clinical diagnosis. Herein, a novel colorimetric sensor array was developed for the detection and identification of bacteria based on the specific affinity and electrostatic interaction between Wulff-type 4-mercaptophenylboronic acid (MPBA)-mercaptoethylamine (MA) cofunctionalized AgNPs (MPBA-MA@AgNPs) and bacteria at various pH. In the neutral and alkaline conditions, AgNPs tended to be dispersed due to the specific affinity between cis-diol residues contained in carbohydrate-rich compositions on the bacterial cell surface and MPBA. Bacterial cells have different carbohydrate compositions on their surface. The differential binding affinity of MPBA on the surface of AgNPs to cis-diol residues of various carbohydrates resulted in a different color change of AgNPs, which could be tuned by pH. On the contrary, AgNPs tended to be aggregated due to the electrostatic interaction between positively charged MA and negatively charged bacteria under acidic conditions. Therefore, using various pH buffer solutions as the sensing elements and MPBA-MA@AgNPs as the indicator, bacteria could be differentiated from each other by their own color response patterns. Moreover, the complex bacteria mixtures could be well discriminated. The method is simple, efficient, and visual and has a potential application in pathogen diagnosis.

Optical fiber amplifier is a vital device in optical communication system, which can directly amplify optical signal. We theoretically propose a type of few-mode quantum dots-doped fiber amplifier (FM-QDFA) in this paper, capable of providing amplification for a number of linear polarization (LP) signal mode groups. The main part of the amplifier is a ring-core fiber doped with PbS quantum dots. And refractive index difference between the annular area and cladding is set to 0.035, which weakens the modal coupling between different LP mode groups. The simulation results show that the ring-core optical fiber not only supports transmission for LP(L=0∼6,1) signal mode group, but also provides relatively uniform gain for LP(L=1∼3,1) signal mode group across the wavelength band 1500 nm–1630 nm that covers the C + L band. For these three signal modes, we explore the differential modal gain (DMG) under 11 pump mode groups (LP(L=0∼10,1)). Noticing that the highest gain for LP(1,1) signal mode is approximately 31 dB obtained at the wavelength of 1530 nm and the DMG is less than 0.5 dB with a LP (7,1) pumping mode.

Fibronectin type III domain-containing protein 5 (FNDC5) plays an important role in white-to-brown adipose tissue conversion in mice. However, there is no report on the role of this protein in Arbas Cashmere goat adipose tissue. We investigated the effect of FNDC5 on the proliferation and differentiation of goat adipose-derived stem cells (gADSCs). We found that FNDC5 promotes the proliferation of gADSCs and increases the levels of p-ERK and p-p38, while it has no effect on the levels of ERK, p38, AKT and p-AKT. What's more, FNDC5 promotes the differentiation of gADSCs into lipid droplets. Overexpression of FNDC5 increased the protein levels of ASC1, UCP1, PPARγ and SREBP1. Additionally, mRNA levels of PPARγ, SREBP1, ACC, and FABP4 increased significantly. FNDC5 knockdown was associated with opposite effects. These results suggest that FNDC5 promotes the proliferation of gADSCs via MAPK signaling pathway and also induces the differentiation of these cells.

Digital holographic tomography (DHT) technology is efficiently utilized to measure optical fiber structure profile. A Mach-Zender off-axis holographic interferometer is used to get fiber wavefront, an angular spectrum reconstruction algorithm is applied to obtain optical path difference (OPD) curves. With an adaptive simultaneous algebraic reconstruction technique (ASART), we obtain a fiber refractive index profile and non-circularity. In fiber wavefront measuring, errors are inevitably caused by measurement accuracy and fiber position offset as fiber rotating. In order to improve fiber structure profile reconstruction accuracy, we propose a novel algorithm to eliminate measuring errors of OPD curves including value drift and position drift, which obviously improves the reconstruction quality. With ASART, we analyze the structure parameters of single-mode spun fiber with various spinning pitches, including refractive index profiles and the fiber non-circularity. The results show that as the shortening of fiber spinning pitch, the refractive index dip in the fiber core is deeper and both cladding non-circularity and core non-circularity are less.

Protein identification is very important in the field of clinical medicine and diagnosis. Here, we report a novel and simple sensor array for the detection and identification of proteins using pH buffer solutions as sensing elements. Different proteins in various pH solutions have different net surface charges including positive, negative or no charge. Such differences may allow a pattern recognition-based sensor array for protein identification. When using negatively charged CdSe/ZnS quantum dots as an indicator, the interactions between a charged protein and quantum dots result in fluorescence changes, generating a differential response pattern for the protein. The result shows that proteins with pI > 7, pI = 7 or pI < 7 can be differentiated successfully. Moreover, complex protein mixtures are also able to be identified and the results demonstrate that surface charge may play an important role in protein sensing. The HSA of different concentrations in water and human urine can also be detected by using the sensor array. It is demonstrated that the proposed sensor array has potential applications in clinical diagnosis and proteomics.

Bacterial biofilms are responsible for many chronic infections because antibacterial agents exhibit poor penetration into the dense matrix barrier and cannot easily reach the internal bacteria. Herein, we reported pH-responsive nanocomposites (PDA@Kana-AgNPs) that could penetrate and disperse biofilms, which were synthesized by the combination of ultrasmall silver nanoparticles (AgNPs) and kanamycin, and then coating with polydopamine. Confocal fluorescence imaging indicated that PDA@Kana-AgNPs could respond to the acidic microenvironment of biofilms, leading to biofilm-triggered on- demand drug release in situ. The zone of inhibition test and Resazurin assay showed that the combination of kanamycin and AgNPs had greater antimicrobial activity against test strains (Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Escherichia coli BL21) than when applied separately. The crystal violet staining test demonstrated that biofilms were effectively dispersed by the proposed nanocomposites. Biocompatibility was also evaluated, which showed that PDA@Kana-AgNPs were non-toxic to mammalian cells. Therefore, the proposed pH-responsive nanocomposites held great potential for efficient antibiotics delivery and showed synergistic antibacterial and antibiofilm activities. This strategy could also be used to encapsulate a variety of antibiotics in combination with other drugs or materials, thereby showing therapeutic potential in preventing biofilm-related infections and realizing fluorescence imaging in situ.

Sensitive and rapid identification of pathogenic microorganisms is of great importance for clinical diagnosis and treatment. In this study, we developed an ultrasensitive colorimetric sensor array (CSA) based on the interactions between aminoglycoside antibiotics (AMGs) and Ag nanoparticles decorated with β-cyclodextrin (AgNPs@β-CD) to discriminate microorganisms quickly and accurately. Microorganisms can absorb different amounts of AMGs after incubation. Upon the addition of AgNPs@β-CD, the corresponding extracellular AMG residues will bind to AgNPs@β-CD, leading to color changes due to the modifications in localized surface plasmon resonance. The array was developed using 4 AMGs as sensing elements and AgNPs@β-CD as the colorimetric probe to generate a unique colorimetric response pattern for each microorganism. Standard chemometric methods indicated excellent discrimination among 20 microorganisms at low concentrations of 2 × 106 CFU/mL. Therefore, this ultrasensitive CSA can be used for microbial discrimination portably and efficiently. Importantly, the concentration of microbial discrimination by our array is much lower than that of prior CSAs. This method of extracellular residue sensing also provided a new strategy to improve the sensitivity of conventional CSA in the discrimination of microorganisms, to measure the amount of intercellular uptake of AMGs by microorganisms, and to screen drugs that can easily be accumulated by the pathogenic microorganisms.

Established Verdet constant test system based on Faraday rotating mirror (FRM). It is found that FRM eliminates the influence of linear birefringence, indicating that the introduction of FRM can compensate for the Verdet constant.

A terbium doped silica fiber is fabricated by MCVD, and treated by high magnetic field. Compare to the untreated fiber, the Verdet constant of the treated fiber is increased by 29%.