Search

The disturbance of flushing to the electrode wire exists in conventional top and bottom flushing process and the machined surface easily being burned in the dry process, a novel dielectric fluid feeding method (moistened wire method) with near-dry high-speed reciprocating wire electrical discharge machine (HS-WEDM) was proposed. A dielectric fluid was poured onto a drum to achieve a moistened wire and packed into the discharge gap by a high-speed running molybdenum wire, and form a gas-liquid double-layer dielectric for discharge machining, cooling and cleaning for the working material. The effect of four processing (conventional top and bottom flushing with emulsion, the dry with atmospheric, the moistened wire with emulsion and moistened wire with emulsion-SiC nanofluids) during the finishing process on the kerf width, average cutting speed, surface roughness, surface morphology, and corner accuracy of the Cr12MoV die steel was studied. Compared to the conventional top and bottom flushingprocess, the moistened wires with emulsion and emulsion-SiC nanofluid processes maintained the high cutting speeds and obtained smooth machined surfaces. The Ra values decreased by 39.8% and 45.8%, the inner circle radius decreased by 4.1% and 4.9%, and outer circle radius decreased by 3.4% and 10.3%, respectively. The results showed that the moistened wire process improved the machined surface quality and corner accuracy of 90° profile without sacrificing the average cutting speed due to their moderate discharge gaps. Compared with the moistened wires with emulsion process, the moistened wires with emulsion-SiC nanofluid process further improved machined quality with lower surface roughness and corner error.

Flow battery electrodes are vital for performing redox reactions, and an in-depth understanding of reaction kinetics and spatial distribution differences in electrodes is very important for improving the efficiency of electrochemical reactions. In this study, a reflection-type phase-sensitive weak measurement imaging system was developed for the detection of flow batteries. The phase difference between two polarization components in total internal reflection caused by electrode redox processes was measured by weak value amplification. The resulting refractive index resolution of the imaging system was estimated to be 2.8-4.2 × 10-6 RIU. The real-time monitoring ability of the system was demonstrated by linear sweep voltammetry tests of vanadium redox batteries. Compared to traditional optical methods, the proposed weak measurement imaging sensor did not require coating, as it can be used in acid electrolytes of vanadium flow batteries. Meanwhile, the weak value amplification effect led to a higher resolution than the total internal reflection system shown in our previous work, thereby resulting in more accurate detection of electrochemical reactions. In sum, the proposed sensor looks very promising for the detection of electrochemical reactions in flow batteries, water splitting, electrochemical corrosion, and electrocatalysis.

In this paper, possibility of improving high-speed reciprocating wire electrical discharge machine (HS-WEDM) machining performances using SiC nanofluids was studied. The performances of SiC nanofluid high-speed WEDM and conventional emulsion dielectric high-speed WEDM were compared. An extra dielectric circulating system was used to satisfy requirement of adding SiC nanofluids. Type of operation, dielectric medium combination, and pulse on time were taken as considerable process parameters of performance of average cutting speed (ACS), surface roughness (SR), surface morphology, recast layer thickness, and material transfer. The result showed that the SiC nanofluids dielectric medium gives a better surface quality and average cutting speed as compared to conventional emulsion dielectric. The average cutting speed increased from 16.9 to 21.22 mm2/min, surface roughness improved from 1.463 to 1.233 μm, and recast layer thickness reduced from 24.7 to 12.9 μm during the HS-WEDM multiple cutting process. The secondary discharge during SiC nanofluids multi-cutting process is the main reason for improvement of the surface quality. Furthermore, scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) investigation revealed a substantial transform of carbon and silicon from SiC nanofluids to the workpiece surface.

In this study, a method to improve the detection accuracy of a “weak measurement” system of optical rotation was proposed by determining the optimal total phase difference of the system. Analysis of the characteristics of weak measurement regime of the system under different total phase differences provided the total phase difference corresponding to the regime with the smallest ratio of system noise level to sensitivity (that is, the highest system resolution). In this regime, an optical rotation resolution of 5.522 × 10−6° was obtained, which is nearly an order of magnitude higher than the original system.

A system containing spectral-domain phase microscopy and fluorescence microscopy has been developed to decode and detect thickness-encoded suspension arrays. The spectral-domain phase imaging path is used for decoding the thickness of the micro glass pieces while the fluorescence imaging path is used for quantifying the targeted analytes. The spectral-domain phase microscopy uses a spectral domain phase retrieval technique so that it has a high-dynamic thickness imaging range and submicron-scale thickness resolution, increasing the encoding efficiency and decoding precision. The thickness decoding capability of the system has been demonstrated by multiplexed immunoassay experiments. The quantitative analysis capability has been verified by concentration gradient experiments.

A quantitative understanding about the optical scattering of medium plays an important role in many common but important application fields including optical imaging, optical communication, and optical remote sensing. In this paper, two quantitative models about single scattering and multiple scattering were established based on the different polarization properties of these two scattering processes on the condition of paraxial approximation. The related approximate explicit functions about the light scattering characteristics through fog are solved. Moreover, on the basis of scattering models, the depolarization ratio of broad-band polarized light is also measured. The physical models are demonstrated very consistent with the experimental results and Monte Carlo simulations. These works greatly simplify previous models and have a significant promotion to the study of medium scattering characteristics.

A multiple-reflection scheme was proposed to improve the sensitivity and resolution of interferometric weak measurement by introducing a cuboid prism device in the optical path. Increasing the number of reflection in a total internal reflection weak value amplification (WVA) system resulted in a 3.8 fold improvement in the sensitivity of the central wavelength shift to refractive index unit (RIU) (from 1788 nm/RIU to 6821 nm/RIU). Using the multiple reflection device, a RIU resolution of $2.7\times 10$ -7 RIU was obtained. The real-time deposition process of dopamine is monitored.

Objectives To investigate fetal hemodynamic alterations using transabdominal ultrasound in fetuses with isolated mild‐to‐moderate ventriculomegaly (VM). Methods Fetuses diagnosed with isolated mild‐to‐moderate VM by transabdominal ultrasound were evaluated for hemodynamic changes, including changes in fetal cardiac function, the umbilical artery, the ductus venosus, and the middle cerebral artery. The fetuses with isolated mild‐to‐moderate VM were divided into 2 groups, namely, before 32 weeks’ gestation (20 weeks–31 weeks 6 days) and after 32 weeks’ gestation (32–38 weeks), and matched to corresponding healthy control fetuses. Results The 53 fetuses with VM before 32 weeks had a longer mean isovolumetric relaxation time (IRT; mean ± SD, 42.9 ± 6.8 versus 40.4 ± 5.0 milliseconds; P

A simple transmission optical rotation (OR) configuration based on weak measurement was developed for the real-time and relatively high precision determination of chiral molecules. According to the theory of optical weak measurement, the shift of the central wavelength of output spectra bears a close relationship with the angle of pre-selected polarization in the frequency domain. Hence, by altering the pre-selected polarization state with the OR, the lactate enantiomers can be detected. The optical activity is not only relative to the concentration of the tested chiral sample but also can be quantitatively analyzed via the shift of the central wavelength of output spectra. Meanwhile, it can be collected in real time. Since the proposed weak measurement system is not sensitive to the refractive index change, it works well in complicated circumstances. Against this background, the experiments of determination of D- and L-lactate were conducted to obtain the optical activity of D- and L-lactate. The experiments showed that the two isomers of chiral lactate exhibited opposite responses. A resolution of 5.7 × 10−4 for D- and L-lactate determination was reached based on the system, which shows a relatively high sensitivity about 3 orders of magnitude higher than that of traditional polarimeters. Moreover, the proposed method is successfully applied for the detection of L-lactate in lactate cream samples. Furthermore, the weak measurement still has great advantages, such as real-time detection, a simple setup, high robustness, high stability and low cost. As a promising method, this real-time and high resolution determination approach matters much in clinical diagnosis, food safety and biological systems.

Reverse design is a frontier direction in the optical research field. In this work, reverse design is applied to the design of terahertz devices. We have employed direct binary search (DBS) and binary particle swarm optimization (BPSO) algorithms to design pixel-type terahertz band-pass filters, respectively. Through a comparative analysis of the designed devices, we found that BPSO algorithm converged faster than DBS algorithm, and the device performance is better on out-of-band suppression. We have fabricated a sample utilizing femtosecond laser micromachining and characterized it by terahertz time-domain spectroscopy. The experimental results were consistent with the finite difference time domain (FDTD) simulation. Our method can simultaneously optimize multiple characteristics of the band-pass filters, including the peak transmittance, out-of-band transmittance, bandwidth, and polarization stability, which can not be achieved by traditional optical design methods.

In this paper, we propose a linear differential detection system based on a frequency domain weak measurement. The system can be used for detecting optical substances. Moreover, we completed an experiment to detect himan serum albumin (HSA) content in a mixture of human serum albumin and l-proline via dialysis. This work also proves the differential function of the system. This experiment can be further extended to detecting protein content in a mixed solution that contains protein macromolecules and various small molecules. It is very important for detecting molecules without photomarking in solutions of complex biological samples. In this paper, the system has an optical resolution of 1.39 × 10-5, and resolution of 4.06 × 10-8 mol/L for himan serum protein solution.

OBJECTIVES To quantitatively assess prenatal diagnostic performance of three-dimensional ultrasound (3D-US) for posterior fossa anomalies (PFA) and establish a preliminarily 3D-US prediction model. METHODS Sixty singleton fetuses suspected of PFA by 2D-US presented their detailed 3D-US evaluation. The surface area of vermis (SAV), brainstem-vermis, and brainstem-tentorium angles were measured by 3D-US. The good prognosis was defined as normal neurodevelopmental outcome. MRI and autopsy were the diagnostic reference standard. RESULTS There was a significant difference between 2D-US (60.0%, 36/60) and 3D-US (94.8%, 55/58) for the diagnostic accuracy (P < .01). Prenatal 3D-US prediction model was established with observed/expected SAV as the main predictor (area under the curve [AUC]: 0.901; 95% CI, 0.810-0.992, P < .001). When it was more than 107.5%, the prognosis seemed to be good (sensitivity: 96.4%, specificity: 26.7%), which led to consideration of mega cisterna magna, Blake pouch cyst, or small arachnoid cyst. The prognosis appeared to be poor when it was less than 73% (sensitivity: 71.4%, specificity: 100%), and the diagnosis tended to be a Dandy-Walker malformation, vermian hypoplasia, and cerebellar hypoplasia. Brainstem-vermis and brainstem-tentorium angles were the secondary indicators (AUC: 0.689 vs 0.761; 95% CI, 0.541-0.836 vs 0.624-0.897, P = .014 vs.001). CONCLUSIONS It seems that the exact types of PFA can be effectively diagnosed by quantitative indicators of 3D-US.

Bacterial degradation of organosulfonates plays an important role in sulfur recycling, and has been extensively studied. However, this process in anaerobic bacteria especially gut bacteria is little known despite of its potential significant impact on human health with the production of toxic H2S. Here, we describe the structural and biochemical characterization of an oxygen-sensitive enzyme that catalyzes the radical-mediated C-S bond cleavage of isethionate to form sulfite and acetaldehyde. We demonstrate its involvement in pathways that enables C2 sulfonates to be used as terminal electron acceptors for anaerobic respiration in sulfate- and sulfite-reducing bacteria. Furthermore, it plays a key role in converting bile salt-derived taurine into H2S in the disease-associated gut bacterium Bilophila wadsworthia. The enzymes and transporters in these anaerobic pathways expand our understanding of microbial sulfur metabolism, and help deciphering the complex web of microbial pathways involved in the transformation of sulfur compounds in the gut., The C2 sulfonates taurine and isethionate are also present in the anaerobic mammalian gut, where they are converted into toxic H2S by sulfate and sulfite-reducing bacteria. Here the authors characterise the O2-sensitive enzyme IseG that catalyzes the C-S bond cleavage of isethionate and show that IseG also plays a key role in converting taurine into H2S in Bilophila wadsworthia.

We propose a method for sensing the non-specific orientation magnetic field based on a simple frequency domain weak measurement system. The magnetic fields with different directions and magnitudes induce the phase differences. It experimentally and theoretically demonstrates the high sensitivity of the system to phase differences, which confirms the potential of detecting magnetic fields. We obtain a sensitivity of 1.19 nm/mT and a resolution of 0.70 × 10−3 mT. Further, the axial and radial magnetic fields can be calculated simultaneously by using the characteristics of the central wavelength and intensity of the spectrum. The method has a simple set-up and offers high sensitivity, real-time response to the magnetic field, suggesting a new way of enriching the detection of the vector magnetic field.

Primary ovarian pregnancy is rare in the classifications of ectopic pregnancy with an incidence of 0.5-3% of all ectopic gestations. The surgical management of ovarian pregnancy is different from the operation of salpingocyesis. Preoperative diagnosis in early pregnancy can help to guide the optimal management. We have reported the case of a 37- year-old woman who presented with a naturally conceived ovarian pregnancy. Transvaginal ultrasound was used in this patient, and made the correct diagnosis of ovarian pregnancy before surgery. We found that transvaginal ultrasound can be helpful in the diagnosis of the location of ectopic pregnancies.

A phase-sensitive fluidic biosensor based on a spectral-domain low-coherence interferometer is presented in this paper. With a fiber optic probe employing the common-path interferometric configuration, subnanometric changes in thickness of the molecular layers can be detected through phase analysis of the acquired interference signal from the sensor surface. Advantages of this biosensor include its picometer-scale thickness sensitivity, 13.9-ms time response, and tolerance to the fluctuation in concentration of the target solution. The capabilities of this biosensor in monitoring specific molecular binding and recognizing specific molecular was successfully demonstrated by using the reactions between the molecules of protein A and IgG. The calculated minimum detectable concentration of IgG is 0.11 &micro, g/mL.

The Fe(II)/2-oxoglutarate-dependent dioxygenases (2-OGDs) catalyze the oxidation of substrates ranging from small molecules to large biomolecules with concomitant oxidation of co-substrate (2-oxoglutarate) into succinate. In the present study, we reported a coupled colorimetric assay that can be generally applied to measure the activities of all members of 2-OGDs family. Succinyl-CoA synthetase is employed as the coupling enzyme to transform succinate produced from 2-OGDs catalysis to form succinyl-CoA with concomitant hydrolysis of ATP to form ADP and orthophosphate. Orthophosphate can be quantitated by reacting it with molybdic acid forming a blue pigment. As a proof of concept, kinetic parameters of ectoine hydroxylase obtained using this method are compared to a traditional time- and labor-consuming HPLC based method. As 2-OGDs family enzymes are important drug targets due to their impressive versatility in catalyzing numerous oxidative reactions that are still very challenging using synthetic chemistry, colorimetric method detailed in the manuscript has the potential to enable the practice of high throughput drug screening for 2-OGDs.

The ability to identify L(+)-ascorbic acid from D(-)-isoascorbic acid in medicinal products is of practical interest. Based on the method of frequency domain weak measurement, a set of common optical path sensors for identification of L(+)-ascorbic acid and D(-)-isoascorbic acid is established. By quantificationally analyzing the magnitude and offset direction of the spectral central wavelength, a good identification of the concentration and the optically active forms of ascorbic acid has been achieved. The sensitivity and resolution of the sensor for optical rotation can reach 34.35 nm/° and ${5.53} \times {{10}^{ - 5}}^\circ $5.53×10-5 ∘, respectively. The detection resolution for L(+)-ascorbic acid is ${2.00} \times {{10}^{ - 4}}\;{\rm mol}/{\rm mL}$2.00×10-4mol/mL, and that for D(-)-isoascorbic acid is ${2.73} \times {{10}^{ - 4}}\;{\rm mol}/{\rm mL}$2.73×10-4mol/mL. The potential of the sensor in the detection of transparent but optically inactive impurities has been verified by comparative experiments of sodium chloride solution. The sensor also has been applied to identify medicinal vitamin C tablets, which verified the feasibility of the method in optically active pharmaceutical solutions with water-insoluble, optically inactive impurities. Since the sensor has the advantages of high precision, real-time, high robustness, and being non-destructive, it has a great prospect in the field of drug detection containing chiral molecules.

In this study, we propose a multifunctional weak measurement system that can measure the optical rotation and the refractive index of solution. The center wavelength of the output spectrum of such a system is sensitive to the optical rotation and the phase difference produced by total internal reflection. The optical resolution and refractive index resolution of the solution determined by the proposed method were 3.26 × 10–5° and 3.93 × 10–7 RIU, respectively, by measuring different concentrations of glucose solution. As the optical rotation and refractive index of the solution are important properties of the solution, this system can be used to determine the type of solute in the solution in the future.

Vibrometry using optical coherence tomography (OCT) can provide valuable information for investigating either the mechanical properties or the physiological function of biological tissues, especially the hearing organs. Real-time imaging of the measured tissues provides structure imaging and spatial guidance for and is thus highly demanded by such vibrometry. However, the traditional time-domain OCT (TD-OCT) systems, although capable of subnanometric vibrometry at large ranges of frequencies, are unable to offer an imaging speed that is high enough to acquire depth-resolved images for guidance. The spectral-domain OCT (SD-OCT) systems, although allowing image-guided vibrometry, are challenged in measuring vibration at high frequencies, particularly for scattering tissue specimens that require longer exposure time to ensure imaging and vibrometry performance. This is because of their limit in the line-scan rate of the CCD, in which the maximum resolvable frequency measured by the SD-OCT is about 1/4 of the CCD line-scan rate in practice. In the present study, we have developed a dual-mode OCT system combining both SD-OCT and TD-OCT modalities for image-guided vibrometry, as the SD-OCT can provide guiding structural images in real-time and, moreover, the TD-OCT can guarantee vibrometry at large ranges of frequencies, including high frequencies. The efficacy of the developed system in image-guided vibrometry has been experimentally demonstrated using both piezoelectric ceramic transducer (PZT) and ex vivo middle-ear samples from guinea pigs. For the vibrometry of PZT, the minimum detectable vibration amplitude was reached at ∼0.01 nm. For the vibrometry of the sound-evoked biological samples, both real-time two-dimensional imaging and subnanometric vibrometry were performed at the frequency ranging from 1 to 40 kHz. These results indicate that our dual-mode OCT system is able to act as an excellent vibrometer enabling image-guided high-frequency measurement.

Phase-sensitive weak measurement systems have been receiving an increasing amount of attention. In this paper, we introduce a series of weak measurement working areas. By adjusting the pre-selection and post-selection states and the total phase difference between vertically polarized light and horizontally polarized light, the measurement of the weak value is amplified by several times in one system. Its applicability is verified in a label-free total internal reflection system. The original sensitivity and resolution are improved at different working areas, reaching 1.85 um/refractive index unit (RIU) and 6.808 × 10-7 RIU, respectively.

Rationale: Uniparental disomy (UPD) gives a description of the inheritance of both homologues of a chromosome pair from the same parent. The consequences of UPD depend on the specific chromosome/segment involved and its parental origin. Patient concerns: We report prenatal phenotypes of 2 rare cases of UPD. Diagnoses: The prenatal phenotype of case 1 included sonographic markers such as enlarged nuchal translucency (NT), absent nasal bone, short femur and humerus length, and several structural malformations involving Dandy–Walker malformation and congenital heart defects. The prenatal phenotype of Case 2 are sonographic markers, including enlarged NT, thickened nuchal fold, ascites, and polyhydramnios without apparent structural malformations. Interventions: Conventional G-band karyotype appears normal in case 1, while it shows normal chromosomes with a small supernumerary marker chromosome (sSMC) in case 2. Genetic etiology was left unknown until single-nucleotide polymorphism-based array (SNP-array) was performed, and segmental paternal UPD 22 was identified in case 1 and segmental paternal UPD 14 was found in case 2. Outcomes: The parents of case 1 chose termination of pregnancy. The neonate of case 2 was born prematurely with a bellshaped small thorax and died within a day. Lessons: UPD cases are rare and the phenotypes are different, which depend on the origin and affected chromosomal part. If a fetus shows multiple anomalies that cannot be attributed to a common aneuploidy or a genetic syndrome, or manifests some features possibly related to an UPD syndrome, such as detection of sSMC, SNP-array should be considered.

Treatment of hot water extract of the sclerotium of Polyporus rhinocerus (PRW) with murine macrophages including RAW 264.7 cell line and primary macrophages (PMs) could enhance their functional activities. These include a significant up-regulation of pinocytosis; an increase in the production of reactive oxygen species (ROS) and nitric oxide (NO); an increase in tumor necrosis factor alpha (TNF-alpha) production and inducible nitric oxide synthase (iNOS) expression in both RAW 264.7 cells and PMs. Cell surface receptors for yeast-derived beta-glucan, including Dectin-1, CR3, and TLR2, were determined by flow cytometry, and the expression of Dectin-1+ cells on the cell surface decreased in the responses of PMs to PRW. PRW increased phosphorylation of IkappaBalpha, which could trigger the nuclear factor kappa B (NF-kappaB) signal pathway for macrophage activation in RAW 264.7 cells. Therefore, the immunomodulatory effect of PRW could be mediated by macrophage activation via the NF-kappaB signal pathway.