Fiber Bragg grating pressure sensor with enhanced sensitivity

A novel fiber Bragg grating （FBG） pressure sensor with the enhanced sensitivity has been demonstrated. A piston-like diaphragm with a hard core in the center is used to enhance the sensitivity. Both the theoretical analysis and the experimental result show that the radius of the hard core has significant effect on the pressure sensitivity. When the radius of the hard core is 1.5 mm, a pressure sensitivity of 7.23 nm/MPa has been achieved.

Microanalysis of silver jewellery by laser-ablation laser-induced breakdown spectroscopy with enhanced sensitivity and minimal sample ablation

Laser-ablation laser-induced breakdown spectroscopy （LA-LIBS） based on single Nd：YAG laser is used to analyze copper impurity in silver jewellery with enhanced sensitivity and minimal sample ablation. 6-30 folds signal enhancement can be achieved under the re-excitation of the breakdown laser and the spatial resolution is only determined by the ablation laser. 50 ppm limit of detection of copper is achieved when the crater diameter is 17.2 μm under current experimental condition. This technique gives higher analysis sensitivity under the same sample ablation in comparison with single pulse （SP） LIBS. It is useful for high sensitive element mieroanalvsis of precious samples.

Exceptional-point-enhanced sensing in an all-fiber bending sensor

An exceptional-point(EP)enhanced fiber-optic bending sensor is reported.The sensor is implemented based on paritytime(PT)-symmetry using two coupled Fabry-Perot(FP)resonators consisting of three cascaded fiber Bragg gratings(FBGs)inscribed in an erbium-ytterbium co-doped fiber(EYDF).The EP is achieved by controlling the pumping power to manipulate the gain and loss of the gain and loss FP resonators.Once a bending force is applied to the gain FP resonator to make the operation of the system away from its EP,frequency splitting occurs,and the frequency spacing is a nonlinear function of the bending curvature,with an increased slope near the EP.Thus,by measuring the frequency spacing,the bending information is measured with increased sensitivity.To achieve high-speed and high-resolution interrogation,the optical spectral response of the sensor is converted to the microwave domain by implementing a dual-passband microwave-photonic filter(MPF),with the spacing between the two passbands equal to that of the frequency splitting.The proposed sensor is evaluated experimentally.A curvature sensing range from 0.28 to 2.74 m^(−1) is achieved with an accuracy of 7.56×10^(−4 )m^(−1 )and a sensitivity of 1.32 GHz/m^(−1),which is more than 4 times higher than those reported previously.

Estimation of enhanced low dose rate sensitivity mechanisms using temperature switching irradiation on gate-controlled lateral PNP transistor

The mechanisms occurring when the switched temperature technique is applied, as an accelerated enhanced low dose rate sensitivity （ELDRS） test technique, are investigated in terms of a specially designed gate-controlled lateral PNP transistor （GLPNP） that used to extract the interface traps （Nit） and oxide trapped charges （Not）. Electrical characteristics in GLPNP transistors induced by 60Co gamma irradiation are measured in situ as a function of total dose, showing that generation of Nit in the oxide is the primary cause of base current variations for the GLPNP. Based on the analysis of the variations of Nit and Not, with switching the temperature, the properties of accelerated protons release and suppressed protons loss play critical roles in determining the increased Nit formation leading to the base current degradation with dose accumulation. Simultaneously the hydrogen cracking mechanisms responsible for additional protons release are related to the neutralization of Not extending enhanced Nit buildup. In this study the switched temperature irradiation has been employed to conservatively estimate the ELDRS of GLPNP, which provides us with a new insight into the test technique for ELDRS.

Studies on the Phenylfluorone-Mo(Ⅵ) Complex as Interacting Mode Spectroscopic Probe of Protein in OP Microemulsion Medium

The application of phenylfluorone (PF)-Mo(VI) complex as a spectroscopic probe is studied. In the presence of OP microemulsion at pH 3.04, PF-Mo(Ⅵ) complex combines protein rapidly to form a stable compound and the absorbance at 527 nm is in proportion to the concentration of protein in the range 0-16 μg mL-1 for bovine serum albumin (BSA). OP microemuslion media is introduced into protein determination, it has increased markedly the sensitivity of the system. The molar absorption coefficient was 5.98×l06 L mol-1 cm-1 for BSA. The assay, with sensitivity, simplicity and tolerance to many foreign substances, is applied to the determination of protein in samples with satisfactory results. Moreover, the binding number of BSA with the complex, which is determined by molar ratio and slope ratio methods, is in good agreement.

Effect of ionizing radiation on dual 8-bit analog-to-digital converters (AD9058) with various dose rates and bias conditions

The radiation effects on several properties （reference voltage, digital output logic voltage, and supply current） of dual 8-bit analog-to-digital （A/D） converters （AD9058） under various biased conditions are investigated in this paper. Gamma ray and 10-MeV proton irradiation are selected for a detailed evaluation and comparison. Based on the measurement results induced by the gamma ray with various dose rates, the devices exhibit enhanced low dose rate sensitivity （ELDRS） under zero and working bias conditions. Meanwhile, it is obvious that the ELDRS is more severe under the working bias condition than under the zero bias condition. The degradation of AD9058 does not display obvious ELDRS during 10-MeV proton irradiation with the selected flux.

Sensitivity-enhanced Experiments for the Measurement of J and Dipolar Coupling Constants

A sensitivity-enhanced IPAP NMR experiment was described in this paper, whichseparates the ~1H-^(15)N doublets into two different spectra to alleviate the problem of resonanceoverlaps and achieve the accurate measurement of J and residual dipolar coupling constants inproteins. This experiment offered 20%―60% sensitivity enhancement over the original IPAPexperiment, and therefore produced more measurable resonances. Pulsed field gradient was used forcoherence selection. Water-flip-back approach was used for water suppression. Thesensitivity-enhanced IPAP experiment was employed in the measurement of ~1J_(NH) and ~1D_(NH)constants of the protein UBC9.

Raltitrexed as a synergistic hyperthermia chemotherapy drug screened in patient-derived colorectal cancer organoids

Objective:Organoids have recently been used as in vitro models to screen chemotherapy drugs in combination with hyperthermia treatment in colorectal cancer.Our research aimed to establish a library of patient-derived colorectal cancer organoids to evaluate synergism between chemotherapy drugs and hyperthermia;validate an index of the hyperthermia chemotherapy sensitization enhancement ratio(HCSER)to identify the chemotherapeutics most enhanced by hyperthermia;and recommend chemotherapy drugs for hyperthermic intraperitoneal treatment.Methods:Organoids were grown from cells extracted from colorectal cancer patient samples or colorectal cancer cell lines.Cells from both sources were encapsulated in 3 D Matrigel droplets,which were formulated in microfluidics and phase-transferred into identical cell-laden Matrigel microspheres.The microspheres were seeded in 96-well plates,with each well containing a single microsphere that developed into an organoid after 7 days.The organoids were used to evaluate the efficacy of chemotherapy drugs at both 37℃ as a control and 43℃ for 90 min to examine hyperthermia synergism.Cell viability was counted with 10%CCK8.Results:We successfully established a library of colorectal cancer organoids from 22 patient parental tumors.We examined the hyperthermia synergism of 7 commonly used hyperthermic intraperitoneal chemotherapy drugs.In 11 of the 22 patient organoids,raltitrexed had significant hyperthermia synergism,which was indexed as the highest HCSER score within each patient group.Conclusions:Our results primarily demonstrated the use of patient-derived colorectal cancer organoids as in vitro models to evaluate hyperthermia synergistic chemotherapeutics.We found that hyperthermia enhanced the effect of raltitrexed the most among the common anti-colorectal cancer drugs.

In situ calcite U-Pb geochronology by high-sensitivity single-collector LA-SF-ICP-MS

U-Pb geochronology of calcite using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is an emerging method,with potential applications to a vast array of geological problems.Due to the low levels of U and Pb in calcite,measurement using higher-sensitivity instruments,such as sector field (SF) ICP-MS,have advantages over more commonly used quadrupole (Q) ICP-MS instruments.Using a Thermo Element XR ICP-MS,we demonstrate that the Jet+X cone combination with the N_(2) enhancement technique provides the best sensitivity for measuring U and Pb isotopes.This higher sensitivity improves the precision of calcite U-Pb isotope measurements,and permits dating at high spatial resolutions (<110μm) and for samples containing low contents of^(238)U (<1μg g^(–1)) and/or^(207)Pb (i.e.,young samples<10 Ma).Using a spot size of 85μm with a low fluence (~2.0 J cm^(–2)),the laser-induced elemental fractionation of^(206)Pb/^(238)U in the NIST SRM 614,ARM-3 and WC-1 reference materials are insignificant (<2.2%).Adopting the optimized instrument parameters,we analysed four commonly-used calcite U-Pb reference materials (WC-1,Duff Brown Tank,JT,and ASH-15).The results match well with published isotope dilution data,demonstrating the reliability of our technique.ARM-3,an andesitic glass,is shown to be an appropriate reference material for both^(207)Pb/^(206)Pb calibration and instrument optimization because of its moderate contents of U(~3.75μg g^(–1)) and Pb (~12.7μg g^(–1)).We further demonstrate that the image-guided approach using LA-ICP-MS elemental mapping is an efficient tool in obtaining robust ages.

Enhancement of the angular rotation measurement sensitivity based on SU(2)and SU(1,1) interferometers

We investigate the sensitivity of the angular rotation measurement with the method of homodyne detection in SU(2) and SU(1,1) interferometers by employing orbital angular momentum(OAM). By combining a coherent beam with a vacuum beam in an SU(2) interferometer, we get the sensitivity of the angular rotation measurement as 1/(2N^(1/2)l). We can surpass the limit of the angular rotation measurement in an SU(1,1) interferometer by combining a coherent beam with a vacuum beam or a squeezed vacuum beam when the probe beam has OAM. Without injection, the sensitivity can reach 1/(2N^(1/2)l). In addition, by employing another construction of an SU(1,1) interferometer where the pump beam has OAM, with the same injection of an SU(1,1) interferometer, the sensitivity of the angular rotation measurement can be improved by a factor of 2, reaching 1/(4Nl). The results confirm the potential of this technology for precision measurements in angular rotation measurements.

Enhancement of Surface Plasmon Fiber Sensor Sensitivity Through the Grafting of Gold Nanoparticles

The optical fibers,coated with plasmonic active metal films,represent the simple and unpretentious sensors,potentially useful for measurements of physical or chemical quantities and wide range of analytical application.All fiber-based plasmonic sensors operate on the same physical principle based on changes in the position of the plasmon absorption peak induced by a variation of surrounding medium refractive index.However,the observed spectral differences are often weak,and thus an enhancement of sensor sensitivity is strongly required.In this paper,we propose the immobilization of gold nanoparticles with sharp edges on the thin gold layer,deposited on the multimode fiber surface for improvement of the sensor functionality.The morphological and compositional changes in the gold covered fiber surface were determined by using the atomic force microscopy,scanning electron microscopy,and energy-dispersive X-ray spectroscopy methods.As a result of gold nanoparticles immobilization,the pronounced plasmon energy concentration near the fiber surface occurred,thus enhancing the response of the proposed hybrid plasmonic system to the variation of ambient refractive index.The position of plasmon absorption in the case of the created plasmonic structure was shown to be more sensitive to the changes in the surrounding medium in comparison with the standard sensors based on the bare gold layer.

Diversiform gas sensors based on two-dimensional nanomaterials

Two-dimensional(2D)nanomaterials have been widely used in gas sensing due to their large specific surface area,high surface reactivity,and excellent gas adsorption properties.This paper reviews the typical synthesis methods of various types of 2D nanomaterials and summarizes the recent progress in gas sensors based on 2D materials,such as noble metal nanoparticles(NPs),metal oxides(MOS),conductive polymers,other new 2D materials.The methods of doping,modification,and photoexcitation can effectively improve the gas-sensing properties of 2D materials.The sensitive mechanisms of heterojunction,Schottky junction,and photoexcitation in 2D material sensors are discussed in detail.This paper discusses the application prospects of 2D materials in wearable gas sensors,food safety,and self-powered sensing,and provides ideas for further applications in environmental quality monitoring and disease diagnosis.In addition,the opportunities and challenges for gas sensors based on 2D materials are also discussed.

Effect of Kang’ai Injection (康艾注射液) on Serum Level of Soluble Interleukin-2 Receptor and Vascular Endothelial Growth Factor in Patients with Esophageal Carcinoma during Radiotherapy

Objective： To observe the effect of Kang＇ai Injection （康艾注射液, KAI） on serum level of soluble interleukin-2 receptor （sIL-2R） and vascular endothelial growth factor （VEGF） in patients with esophageal carcinoma （EC） during radiotherapy （RT）, and to investigate its synergistic effect with RT and its influence on immunological function of the body. Methods： One hundred and seventy patients with EC, who had missed the chance of surgical operational therapy, were assigned to the treated group （90 cases） and the RT group （80 cases）, and at the same time a control group consisting of 80 inpatients without tumors was set up. Patients in the RT group were treated with RT alone but KAI was given additionally to those in the treated group, with 50 ml given once per day via intravenous dripping, 15 days as one course, and 2 courses administered in total. The immediate therapeutic efficacy and changes of serum slL-2R and VEGF levels were observed, and the effect of KAI on patients＇ quality of life （QOF） was evaluated by Karnofsky scoring. Results： In 16 patients of the treated group it was completely remission （OR）, in 54 partially remission （PR）, in 18 it was stabilized disease （SD） and in 2 progressive disease （PD）, with the total effective rate （CR ＋ PR） as 77.8%, while in those of the control group it was 12, 46, 18, 4 and 72.5%, respectively, the immediate therapeutic efficacy in the treated group was somewhat better than that in the RT group, but showed no statistical significance （P〉0.05）. Serum levels of slL-2R and VEGF in all the patients before treatment were higher than those in the control group, which were decreased after treatment in both groups （P〈0.05）, but the improvement in the treated group was better than that in the RT group, showing significant difference （P〈0.05）, and patients＇ QOF improved more significantly in the former as well （62.2 % vs 40.0%, P〈 0.05）. Conclusion： KAI in combination with RT in treating patients with EC could enhance the immunological function of patients, improve their QOF and enhance their sensitivity to RT.

Radiosensitization of human pancreatic cancer by piperlongumine analogues

Radiotherapy is commonly used to treat advanced pancreatic cancers and can improve survival by2 months in combination with gemcitabine.However,prognosis and survival improvement remain unsatisfactory,and effective therapies are urgently needed.Piperlongumine has been demonstrated to have therapeutic potentials against various cancers.In this study,we synthesized a series of piperlongumine derivatives and provided evidence that piperlongumine derivatives could be used as effective radiosensitizers in pancreatic cancer.Two compounds enhanced the radiosensitivity of Panc-1 and SW1990 cells.In a pancreatic bi-flank xenograft tumor model,they significantly inhibited tumor growth.Piperlongumine derivatives could induce reactive oxygen species(ROS)expression and regulate the Keapl-Nrf2 protective pathway with enhancement of radiation-induced DNA damage,G2/M-phase cell cycle arrest,and apoptosis.Collectively,our data offer a proof of concept for the use of piperlongumine derivatives as a novel class of radiosensitizers for the treatment of pancreatic cancer.

Ignition enhancement of ethylene/air by NO_x addition

Recently, non-equilibrium plasma assisted combustion （PAC） has been found to be promising in reducing the ignition delay time in hypersonic propulsion system. NO x produced by non-equilibrium plasma can react with intermediates during the fuel oxidation process and thereby has influence on the combustion process. In this study, the effects of NO x addition on the ignition process of both the homogeneous ethylene/air mixtures and the non-premixed diffusion layer are examined numerically. The detailed chemistry for ethylene oxidization together with the NO x sub-mechanism is included in the simulation. Reaction path analysis and sensitivity analysis are conducted to give a mechanistic interpretation for the ignition enhancement by NO x addition. It is found that for both the homogenous and non-premixed ignition processes at normal and elevated pressures, NO 2 addition has little influence on the ignition delay time while NO addition can significantly promote the ignition process. The ignition enhancement is found to be caused by the promotion in hydroxyl radical production which quickly oxidizes ethylene. The promotion in hydroxyl radical production by NO addition is achieved in two ways：one is the direct production of OH through the reaction HO2＋NO = NO2＋OH, and the other is the indirect production of OH through the reactions NO＋O2=NO2＋O and C2H4＋O = C2H3＋OH. Moreover, it is found that similar to the homogeneous ignition process, the acceleration of the diffusion layer ignition is also controlled by the reaction HO2＋NO = NO2＋OH.