Microwave Absolute Distance Measurement Method with Ten-Micron-Level Accuracy and Meter-Level Range Based on Frequency Domain Interferometry.

A microwave absolute distance measurement method with ten-micron-level accuracy and meter-level range based on frequency domain interferometry is proposed and experimentally demonstrated for the first time. Theoretical analysis indicates that an interference phenomenon occurs instantaneously in the frequency domain when combining two homologous broad-spectrum microwave beams with different paths, and the absolute value of the distance difference between the two paths is only inversely proportional to the period of frequency domain interference fringes. The proof-of-principle experiments were performed to prove that the proposed method can achieve absolute distance measurement in the X-band with standard deviations of 15 µm, 17 µm, and 26 µm and within ranges of 1.69 m, 2.69 m, and 3.75 m. Additionally, a displacement resolution of 100 microns was realized. The multi-target recognition performance was also verified in principle. Furthermore, at the expense of a slight decrease in ranging accuracy, a fast distance measurement with the single measurement time of 20 µs was achieved by using a digitizer combined with a Fourier transform analyzer. Compared with the current microwave precision ranging technologies, the proposed method not only has the advantages of high precision, large range, and rapid measurement capability, but the required components are also easily obtainable commercial devices. The proposed method also has better complex engineering applicability, because the ten-micron-level ranging accuracy is achievable only by using a simple Fourier transform without any phase estimation algorithm, which greatly reduces the requirement for signal-to-noise ratio.

Physiological analysis of severe chlamydia psittaci pneumonia and clinical diagnosis after doxycycline-based treatment.

Objective: To describe the clinical spectrum of severe Chlamydia psittaci pneumonia in order to understand the disease better. Methods: Retrospective analysis was made on 31 patients with severe Chlamydia psittaci pneumonia diagnosed in ICU by next-generation sequencing of metagenome Metagenomic next-generation sequencing(mNGS) from January 2019-November 2022, including clinical characteristics, laboratory examination results, imaging characteristics, treatment, and prognosis. Results: We included 31 patients with severe Chlamydia psittaci pneumonia, 15 of whom had a history of virus exposure. There were 12 cases with multiple bacterial infections, and the common symptoms included fever (31/31,100%), dyspnea (31/31, 100%), cough (22/31, 71.0%), and myalgia (20/31, 64.5%). Laboratory data showed that white blood cells were average or slightly increased, but the levels of C-reactive protein and neutrophils were high. CT findings of the lung were consolidation (19/31, 61.3%) and pleural effusion (11/31, 35.5%). Only one lobe was involved in 11 patients (35.5%). Before diagnosis, 22 patients (71.0%) did not have atypical pathogens in their antimicrobial regimen. After diagnosis, 19 patients (61.3%) received single drug treatment, of which doxycycline or moxifloxacin were the most commonly used drugs. Among 31 patients, three died, nine improved, and nineteen were cured. Conclusion: The clinical manifestations of severe Chlamydia psittaci pneumonia are non-specific. The application of mNGS can improve the diagnostic accuracy of Chlamydia psittaci pneumonia, reduce the unnecessary use of antibiotics, and shorten the course of the disease. Doxycycline-based treatment is effective for severe chlamydia psittaci pneumonia, but it is necessary to understand the secondary bacterial infection and other complications in the course of the disease.

Bioinformatics prediction of differential miRNAs in non-small cell lung cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancers. The drug resistance of NSCLC has clinically increased. This study aimed to screen miRNAs associated with NSCLC using bioinformatics analysis. We hope that the screened miRNA can provide a research direction for the subsequent treatment of NSCLC. METHODS: We screened out the common miRNAs after compared the NSCLC-related genes in the TCGA database and GEO database. Selected miRNA was performed ROC analysis, survival analysis, and enrichment analysis (GO term and KEGG pathway). RESULTS: A total of 21 miRNAs were screened in the two databases. And they were all highly expressed in normal and low in cancerous tissues. Hsa-mir-30a was selected by ROC analysis and survival analysis. Enrichment analysis showed that the function of hsa-mir-30a is mainly related to cell cycle regulation and drug metabolism. CONCLUSION: Our study found that hsa-mir-30a was differentially expressed in NSCLC, and it mainly affected NSCLC by regulating the cell cycle and drug metabolism.

Independently Tunable Multipurpose Absorber with Single Layer of Metal-Graphene Metamaterials.

This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 µm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.

Ultrawideband terahertz absorber with a graphene-loaded dielectric hemi-ellipsoid.

We herein present a high-performance ultrawideband terahertz absorber with a silicon hemi-ellipsoid (SHE) on a monolayer graphene that is separated by a dielectric spacer from a bottom metal reflector. The constitution of the absorber, which includes dielectric-mode structures and unstructured monolayer graphene, can minimize undesired optical losses in metals and avoid graphene processing. The absorber achieved an ultrawide absorption bandwidth from 2 THz to more than 10 THz with an average absorption of 95.72%, and the relative bandwidth is 133%. The excellent absorption properties are owing to the presence of graphene and the shape morphing of the SHE, in which multiple discrete graphene plasmon resonances (GPRs) and continuous multimode Fabry-Perot resonances (FPRs) can be excited. By coupling the GPRs and FPRs, the absorption spectrum is extended and smoothed to realize an ultrawideband absorber. The incident angular insensitivity within 50° of the absorber is discussed. The results will shed light on the better performance of terahertz trapping, imaging, communication and detection.

[Nontuberculous mycobacteria pulmonary disease: A retrospective analysis].

OBJECTIVE: To analyze the clinical characteristics and drug resistance in patients with non-tuberculous mycobacteria (NTM) pulmonary disease in Changsha Central Hospital of Hunan Province in recent three years.
 Methods: The clinical data of 153 patients with NTM pulmonary disease, who were diagnosed in Changsha Central Hospital of Hunan Province from February 2014 to May 2017, were retrospectively analyzed. According to the concentration of drug sensitivity test, the patients were divided into a low concentration group and a high concentration group. The status of drug sensitivity and drug resistance were examined.
 Results: Among 153 patients, 79 patients (51.63%) were male, 74 patients (48.37%) were female. The mean ages were (60.27±19.46) years. The NTM pulmonary disease mainly occurred in the individuals with bronchiectasis, and the course of disease was long (mean 7.8 years). The clinical symptoms were not specific and mostly misdiagnosed as pulmonary tuberculosis (92.81%). Mycobacterium avium-intracellulare (56.21%) and mycobacterium chelonae-abscess (20.92%) were the majority. The drug-resistance rate of the first-line and second-line anti-tuberculosis drugs was high. The majority was resistant to more than eight drugs, 38.56% patients in the low concentration group were resistant to total drugs, and 25.49% patients in the high concentration group were resistant to total drugs.
 Conclusion: The NTM pulmonary disease is easily misdiagnosed, and the drug resistance rate is high. Identification of mycobacterium species and detection of drug sensitivity play an important role in clinical diagnosis and treatment.

Independently tunable multi-band and ultra-wide-band absorbers based on multilayer metal-graphene metamaterials.

Dynamically and independently tunable absorbers based on multilayer metal-graphene metamaterials are proposed to achieve multi-band and ultra-wide-band absorbing properties at mid-infrared frequencies. Dual-band, triple-band and even more bands absorption can be arbitrarily customized by etching the appropriate number of tandem gold strips in each meta-molecule, as well as stacking multiple metal-graphene layers. Through tuning the Fermi energy level of the graphene in each metal-graphene layer separately, the multiple absorption resonances can be dynamically and independently adjusted. With side-by-side arrangement of the gold strips in each supercell, the proposed structure is rendered to be a promising candidate for ultra-wide-band absorber. The extreme bandwidth exceeding 80% absorption up to 7.5THz can be achieved with a dual-layered structure, and the average peak absorption is 88.5% in the wide-band range for lossless insulating interlayer. For a triple-layered structure, the average peak absorption is 84.7% from 27.5 THz to 38.4 THz with a minimum of 60%. The absorption windows can be even further broadened with more metal-graphene layers. All these results will benefit the integrated microstructure research with simple structure and flexible tunability, and the multilayer structure has potential applications in information processing fields such as filtering, sensing, cloaking objects and other multispectral devices.

Simultaneous measurement of the dynamic emissivity and the radiance of the shocked Al/LiF interface in the near-infrared wavelength.

A novel method based on signal superimposing has been presented to simultaneously measure the dynamic emissivity and the radiance of a shocked sample/window interface in the near-infrared wavelength. In this method, we have used three rectangle laser pulses to illuminate the sample/window interface via an integrating sphere and expect that the reflected laser pulses from the sample/window interface can be superimposed on its thermal radiation at the shocked steady state by time precision synchronization. In the two proving trials, the second laser pulse reflected from the Al/LiF interface has been successfully superimposed on its thermal radiation despite large flyer velocity uncertainty. The dynamic emissivity and the radiance at 1064 nm have been obtained simultaneously from the superimposing signals. The obtained interface temperatures are 1842 ± 82 K and 1666 ± 154 K, respectively, the corresponding release pressures are 65.7 GPa and 62.6 GPa, and the deduced Hugonoit temperatures are consistent with the theoretical calculations. In comparison, the fitting temperatures from the gray body model are 300-500 K higher than our experimental measurement results and the theoretical calculations.

Terahertz radiation in graphene hyperbolic medium excited by an electric dipole.

In this Letter, the enhanced and directional radiation in a wide terahertz (THz) frequency range in a graphene hyperbolic medium excited by an electric dipole is presented. The numerical simulations and theoretical analyses indicate that the enhanced radiation comes from the strong surface plasmon couplings in the graphene hyperbolic medium, consisting of alternative graphene and dielectric substrate layers. The simulation results also show that the peak power flow of the enhanced THz radiation in the graphene hyperbolic medium is dramatically enhanced by more than 1 order of magnitude over that in a general medium within a certain distance from the dipole, and the electromagnetic fields are strongly concentrated in a narrow angle. Also, the radiation fields can be manipulated, and the fields' angular distributions can be tuned by adjusting the dielectric permittivity and thickness of the substrates, and the chemical potential of graphene. Accordingly, it provides a good opportunity for developing miniature, integratable, high-power-density, and tunable radiation sources in the THz band at room temperature.

Dynamically tunable band stop filter enabled by the metal-graphene metamaterials.

Dynamically tunable band stop filter based on metal-graphene metamaterials is proposed and numerically investigated at mid-infrared frequencies. The proposed filter is constructed by unit cells with simple gold strips on the stack of monolayer graphene and the substrate of BaF2. A stable modulation depth up to -23.26 dB can be achieved. Due to the cooperative effect of the "bright-bright" elements, the amount of the gold strips in each unit cell determines the number of the stop-bands, providing a simple and flexible approach to develop multispectral devices. Further investigations illustrate that the location of the stop bands not only can be adjusted by varying the length of gold strips, but also can be dynamically controlled by tuning the Fermi energy level of graphene, and deep modulation is acquired through designing the carrier mobility. With the sensitivity as high as 2393 nm/RIU of the resonances to the varieties of surrounding medium, the structure is also enabled to be an index based sensor. The results will benefit the on plane or integrated micro-structure research with simple structure and flexible tunability, and can be applied in multi-band stop filters, sensors and other graphene-based multispectral devices.

Mediated coupling of surface plasmon polaritons by a moving electron beam.

The mediated coupling of surface plasmon polaritons (SPPs) by a parallel moving electron beam is demonstrated in this paper. The theoretical analysis shows that the electron beam excited spoof surface plasmon polaritons (SSPs) on the grating placed above the metal films play the role as the excitation source in the mediated coupling. The numerical calculations and particle-in-cell simulations demonstrate the significant advantages of the SSPs mediately coupled SPPs in contrast with that coupled by the parallel moving electron beam directly. The photo density of the mediately coupled SPPs reaches up to 106 per cm2 for the electron beam with the charge density 100 nC/cm, which is two orders of magnitude larger than that of the directly coupled SPPs. The tuning band of the mediately coupled SPPs reaches up to 9% for the beam energy ranging from 10 keV to 30 keV, while it almost cannot be tuned for the direct coupling. The lifetime of the mediately coupled SPPs, which reaches up to hundreds of femtoseconds, is also much longer. Accordingly, the mediated coupling may bring great significances for the applications of SPPs.

Plasmon modes of circular cylindrical double-layer graphene.

In this paper, a theoretical investigation on plasmon modes in a circular cylindrical double-layer graphene structure is presented. Due to the interlayer electromagnetic interaction, there exist two branches of plasmon modes, the optical plasmon mode and the acoustic plasmon mode. The characteristics of these two modes, such as mode pattern, effective mode index and propagation loss, are analyzed. The modal behaviors can be effectively tuned by changing the distance between two graphene layers, the chemical potential of graphene and the permittivity of interlayer dielectric. Importantly, the breakup of tradeoff between mode confinement and propagation loss is discovered in the distance-dependent modal behavior, which originates from the unique dispersion properties of a double-layer graphene system. As a consequence, both strong mode confinement and longer propagation length can be achieved. Our results may provide good opportunities for developing applications based on graphene plasmonics in circular cylindrical structure.

Krüppel-Like Factor 4 Enhances Sensitivity of Cisplatin to Lung Cancer Cells and Inhibits Regulating Epithelial-to-Mesenchymal Transition.

In order to improve therapeutic efficacy, it is a current emergency to better know the mechanisms underlying cisplatin resistance in lung cancer cells. In this study, we aim to investigate the role of Krüppel-like factor 4 (KLF4) in cisplatin-resistant lung cancer cells. We developed cisplatin-resistant lung cancer cell line A549/DDP, and then a battery of experiments was used to analyze the effects of KLF4 in cisplatin resistance of lung cancer. We found that KLF4 was significantly downregulated in cisplatin-resistant A549 cells and forced KLF4 expression inhibited cell growth and induced apoptosis. Further, we found that overexpression of KLF4 was able to inhibit cell migration and invasion, to inhibit the expression of Slug, Twist, and vimentin, and to increase the expression of E-cadherin and subsequent inhibition of the EMT process. Thus, overexpression of KLF4 may be a potential strategy for lung cancer treatment, especially for cisplatin-resistant cases.

[Fluorescent Characteristics of Strontium Tetraborate (SrB4O7) Doped with Divalent Lanthanide Elements].

Strontium borate doping with different lanthanide bivalent ions and concentration (SrB4O : Re2+) were synthesized by the high-temperature solid state method. The fluorescent spectral characteristics of SrB4O7 : Re2+ were investigated by the non-polarization con-foucus fluorescence/raman measurement system built by us. The results indicate that the fluorescent spectral characteristics of SrB4O7 : Re2+ is very similar to that of SrB4O7 : Sm2+. The most strong fluorescence line (0-0 line) arises from 5D0 - 7F0 electron transition and the wavelength is 685.41 nm. In addition, two fluorescent bands coming from 5D0 - 7F1 and 5D0 -7F2 electron transition are observed near 700 and 730 nm, respectively. The intensity of 0-0 line of SrB4O7 : Re2+ is at least a magnitude smaller than that of SrB4O7 : Sm2+. A further study on the fluorescent spectrums of SrB4O7 : Re2+ shows that the doping elements and concentration both are the key points that affect the intensity of the fluorescent peaks, which directly decide the amount of Re2+ concerned with irradiance.

Coherent and Tunable Terahertz Radiation from Graphene Surface Plasmon Polarirons Excited by Cyclotron Electron Beam.

Terahertz (THz) radiation can revolutionize modern science and technology. To this date, it remains big challenges to develop intense, coherent and tunable THz radiation sources that can cover the whole THz frequency region either by means of only electronics (both vacuum electronics and semiconductor electronics) or of only photonics (lasers, for example, quantum cascade laser). Here we present a mechanism which can overcome these difficulties in THz radiation generation. Due to the natural periodicity of 2π of both the circular cylindrical graphene structure and cyclotron electron beam (CEB), the surface plasmon polaritions (SPPs) dispersion can cross the light line of dielectric, making transformation of SPPs into radiation immediately possible. The dual natural periodicity also brings significant excellences to the excitation and the transformation. The fundamental and hybrid SPPs modes can be excited and transformed into radiation. The excited SPPs propagate along the cyclotron trajectory together with the beam and gain energy from the beam continuously. The radiation density is enhanced over 300 times, up to 10(5) W/cm(2). The radiation frequency can be widely tuned by adjusting the beam energy or chemical potential. This mechanism opens a way for developing desired THz radiation sources to cover the whole THz frequency regime.

Gbps terahertz external modulator based on a composite metamaterial with a double-channel heterostructure.

The past few decades have witnessed a substantial increase in terahertz (THz) research. Utilizing THz waves to transmit communication and imaging data has created a high demand for phase and amplitude modulation. However, current active THz devices, including modulators and switches, still cannot meet THz system demands. Double-channel heterostructures, an alternative semiconductor system, can support nanoscale two-dimensional electron gases (2DEGs) with high carrier concentration and mobility and provide a new way to develop active THz devices. In this Letter, we present a composite metamaterial structure that combines an equivalent collective dipolar array with a double-channel heterostructure to obtain an effective, ultrafast, and all-electronic grid-controlled THz modulator. Electrical control allows for resonant mode conversion between two different dipolar resonances in the active device, which significantly improves the modulation speed and depth. This THz modulator is the first to achieve a 1 GHz modulation speed and 85% modulation depth during real-time dynamic tests. Moreover, a 1.19 rad phase shift was realized. A wireless free-space-modulation THz communication system based on this external THz modulator was tested using 0.2 Gbps eye patterns. Therefore, this active composite metamaterial modulator provides a basis for the development of effective and ultrafast dynamic devices for THz wireless communication and imaging systems.

[Clinical efficacy of vitamin support in lung adenocarcinoma patients treated with pemetrexed second-line chemotherapy].

OBJECTIVE: To analyze the clinical efficacy and toxicity of vitamin support in lung adenocarcinoma patients treated with pemetrexed second-line chemotherapy. METHODS: Two hundred and eighty-three patients with stage 3/4 lung adenocarcinoma treated at our hospital from August 2010 to August 2013 were included in this study. The lung adenocarcinomas in all the 283 patients were confirmed by pathology or cytology, all were EGFR-negative, and all patients received pemetrexed second line chemotherapy. The 283 patients were randomly divided into two groups: the improved treatment group (142 cases) and the conventional treatment group (141 cases). The patients of conventional treatment group received 400 µg folic acid per os daily for 7 days before the first dose of pemetrexed, and continued until 21 days after the last dose of pemetrexed. Besides, they received 1000 µg vitamin B12 injection at 7 days before the first dose of pemetrexed, and once per cycle of pemetrexed for 3 cycles after the last dose of pemetrexed. The patients of the improved treatment group took 400 µg folic acid daily per os from the day before the first dose to 21 days after the last dose of pemetrexed. They also received 500 µg vitamin B12 by injection one day before the first dose, and one day before each therapy cycle of pemetrexed therapy. RESULTS: The mean number of cycles of pemetrexed chemotherapy was 4 in both groups. In the 142 patients of improved treatment group, complete response (CR) was observed in two cases, partial remission (PR) in 28, stable disease (SD) in 21, and progressive disease (PD) in 91 cases, with a total effective rate of 21.1%. While in the conventional treatment group, CR was observed in one case, PR in 27 cases, SD in 23 cases, and PD in 90 cases, with a total effective rate of 19.9%. The median progression-free survival (PFS) was 3.8 months in the improved treatment group and 4.2 months in the conventional treatment group (P=0.143). The toxicity of chemotherapy was mild in both groups, with no significant difference between the two groups (P>0.05). The most common side effects of hematological system were leukopenia and neutropenia, and the most common side effects of non-blood system were nausea and vomiting. The most common grade 3-4 toxic reaction in both groups was leukopenia and neutropenia, with no significant difference between the two groups (P>0.05). Multivariate analysis showed that the age of patients was an independent factor of grade 3-4 chemotherapy toxic reaction (P<0.05), while gender, the baseline level of PS score or blood system had no significant effect on the grade 3-4 chemotherapy toxic reaction (P>0.05). CONCLUSIONS: Compared with the conventional treatment scheme, the improved treatment scheme has similar therapeutic effects and could be used more conveniently, while the toxic effects of chemotherapy are not increased at the same time. Our results indicate that pemetrexed-based chemotherapy does not need to delay the chemotherapy because of vitamin support treatment.

Dynamic frequency-domain interferometer for absolute distance measurements with high resolution.

A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

Electron beam excitation of surface plasmon polaritons.

In this paper, the excitations of surface plasmon polaritons (SPPs) by both perpendicular and parallel electron beam are investigated. The results of analytical theory and numerical calculation show that the mechanisms of these two excitations are essentially different, and the behavior and properties of SPPs in metal structures strongly depend on the methods of excitation. For the perpendicular excitation, SPPs contain plenty of frequency components, propagate with attenuation and are always accompanied with the transition radiation. Whereas for parallel excitation, SPPs waves are coherent, tunable, propagating without attenuation and the transition radiation does not occur. We also show that there are two modes for the parallel excited SPPs on the metal films and they all can be excited efficiently by the parallel moving electron beam. And the operating frequency of SPPs can be tuned in a large frequency range by adjusting the beam energy.

Note: a novel method to measure the deformation of diamond anvils under high pressure.

A novel and simple method based on optical-fiber frequency domain interferometer to measure the deformation of diamond anvils under high pressure is presented. The working principle and application examples are given in this paper. The deformation of diamond anvils is obtained up to 37.7 GPa, our results verify that the deformation has an obvious difference between uploading and downloading at a given pressure, the maximum difference is up to 4.5 µm at 18.8 GPa, and the cupping effect is observed directly.