Generation of a switchable and tunable rectangular pulse and multi-pulse with different peak powers at the L-band.

A novel, to our knowledge, L-band erbium-doped fiber laser, utilizing a nonlinear optical loop mirror (NOLM) as a mode-locker, is presented in this study. Through precise adjustments of the polarization controllers (PCs), the laser achieves the generation of rectangular pulses with distinct single wavelengths, λ 1=1593n m and λ 2=1571n m, as well as dual-wavelength operation. The laser's operational mode can extend further to include harmonic mode-locking (HML). Furthermore, the investigation reveals the emergence of trapezoidal pulses and low-peak-power rectangular pulses within proximity of the conventional rectangular pulses. Notably, the evolutions of these low-peak-power pulses with the pump power also adhere to the peak power clamping (PPC) effect. Remarkably, the relative positioning of these pulses remains consistent across varying pump power levels or harmonic orders. Intriguingly, the evolution of the trapezoidal pulse with respect to pump power stands in stark contrast to that of the h-shaped pulse.

Measurement and multiplexing of ultra-low duty cycle Nyquist pulse sequences.

In this paper, we propose a novel, to the best of our knowledge, method to our knowledge for generating and accurately measuring Nyquist pulse sequences with an ultra-low duty cycle of only 0.037, which breaks the limitations caused by the noise and bandwidth of the optical sampling oscilloscope (OSO) by using a narrow-bandwidth real-time oscilloscope (OSC) and an electrical spectrum analyzer (ESA). By this method, it is found that the bias point drift of the dual parallel Mach-Zehnder modulator (DPMZM) is the main cause of the distortion of the waveform. In addition, we increase the repetition rate of Nyquist pulse sequences by a factor of 16 by multiplexing the unmodulated Nyquist pulse sequences.

Ultra-flat multicarrier light source based on recirculating frequency shift loop driven by a parity-time symmetric optoelectronic oscillator.

A multicarrier light source based on a recirculating frequency shift loop (RFSL) driven by a parity-time (PT)-symmetric optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The impact of the side-mode suppression ratio (SMSR) of the radio frequency (RF) signal on the multicarrier is studied for the first time, to our knowledge. The RFSL driven by PT-symmetric OEO significantly optimizes the phase noise and flatness of the multicarrier, facilitating the system miniaturization. In the experiment, a 10.019 GHz RF signal with a SMSR of 42 dB is generated with -98.63d B c/H z measured phase noise at 10 kHz offset frequency (actual phase noise should be lower than -122.87d B c/H z). Up to 120 subcarriers with 2.32 dB flatness are obtained successfully, covering the overall bandwidth of approximately 1.2 THz.

Observation of square- and h-shaped pulse from a mode-locked erbium-doped fiber laser.

We demonstrate the generation of a type of square-shaped pulse in a passively mode-locked erbium-doped fiber laser based on the nonlinear optical loop mirror technique. Through adjusting the pump power and polarization state, square-shaped pulses are generated. Furthermore, we investigate the pulse profile in relation to the optical spectrum. By filtering out short-wavelength spectrum components gradually, pulse shaping is achieved, and the top of the square-shaped pulse becomes flat. Subsequently, by filtering out long-wavelength spectrum components, a type of h-shaped pulse is obtained and the formation reason is also investigated.

[Research on Reliability Design and Verification of CT Based on Clinical Application Data].

Based on the clinical application data of medical X-ray computed tomography (CT) in the Shanghai Sixth People's Hospital, this study transformed it into the product reliability index requirements, and took the mechanical representative component-examination table (hereinafter referred to as "patient table") and the electronic representative component-DCB (data control board) as examples. Based on the relationship between failure characteristics and clinical application data, a complete set of closed-loop implementation methods from reliability index requirements to reliability design and verification are discussed.

[Research on Reliability Index and Realization of Magnetic Resonance (MR) Based on Clinical Use Condition].

Combined with the clinical use condition of MR in use in Shanghai Sixth People's Hospital, MR components are divided into scanning type I and scanning type II. At the same time, combined with the main loss force of MR components, the research divides MR components into dynamic components and electric thermal components. In this study, a complete set of MR system reliability indexes and implementation methods are given, including system reliability index determination, system reliability allocation, component reliability index realization, system reliability prediction and system reliability verification. At the same time, this study also gives the methods of reliability prediction and reliability verification, and gives the MTBF calculation method of MR system based on clinical use data statistics.

A Novel Method of Measuring Instantaneous Frequency of an Ultrafast Frequency Modulated Continuous-Wave Laser.

Ultrafast linear frequency modulated continuous-wave (FMCW) lasers are a special category of CW lasers. The linear FMCW laser is the light source for many sensing applications, especially for light detection and ranging (LiDAR). However, systems for the generation of high quality linear FMCW light are limited and diverse in terms of technical approaches and mechanisms. Due to a lack of characterization methods for linear FMCW lasers, it is difficult to compare and judge the generation systems in the same category. We propose a novel scheme for measuring the mapping relationship between instantaneous frequency and time of a FMCW laser based on a modified coherent optical spectrum analyzer (COSA) and digital signal processing (DSP) method. Our method has the potential to measure the instantaneous frequency of a FMCW laser at an unlimited sweep rate. In this paper, we demonstrate how to use this new method to precisely measure a FMCW laser at a large fast sweep rate of 5000 THz/s by both simulation and experiments. We find experimentally that the uncertainty of this method is less than 100 kHz and can be improved further if a frequency feedback servo system is introduced to stabilize the local CW laser.

Multiple stable states of dissipative soliton resonance in a passively mode-locked Yb-doped fiber laser.

Dissipative soliton resonance (DSR) with multiple stable states has been experimentally demonstrated in a passively mode-locked Yb-doped fiber laser. The generation of the DSR square pulse has been achieved with the nonlinear optical loop mirror technique. The duration of the square pulse varies from 16 to 123 ns, while the amplitude of the pulse remains constant. Experimentally, by fixing the pump power and changing the orientations of the polarization controllers, we have observed three different square pulses that all operate in the DSR regime. At the same time, we have obtained a wavelength-tunable square pulse, which demonstrates that the DSR and operation wavelength are independent of each other. We also analyzed the ideal state in the DSR regime.

Broadband linearly chirped light source with narrow linewidth based on external modulation.

An external modulation method is proposed and experimentally demonstrated for the generation of linearly chirped light over broadband with narrow linewidth. Our chirped light source is a combination of an optical recirculating frequency shifter loop and an optical frequency linear sweeper. A linearly chirped light over a range of 200 GHz at a chirp rate of 3.6×1016 Hz/s is generated. The instantaneous linewidth of the chirped light is estimated to be less than 50 kHz.

Stable L-band multi-wavelength SOA fiber laser based on polarization rotation.

We propose and experimentally demonstrate a stable multi-wavelength fiber ring laser operating in the L-band with wavelength spacing of 25 GHz. The mechanism is induced by a polarization rotation intensity equalizer consisting of a semiconductor optical amplifier and polarization devices. A Fabry-Perot filter is inserted into the cavity to serve as a multi-wavelength selection device. Stable L-band multi-wavelength lasing with 3 dB uniformity of 21.2 nm, and simultaneous oscillation of 101 lines with wavelength spacing of 25 GHz, is obtained.

Generation of a square pulse with ultra-wide tuning range in a passively mode-locked Yb-doped fiber laser.

We have experimentally demonstrated a square pulse in a passively mode-locked Yb-doped fiber ring laser operating in the dissipative soliton resonance (DSR) region based on the nonlinear polarization rotation technique. In our experiment, a 1.5-km long single-mode fiber (SMF) is inserted into the cavity to increase the cavity length. The total cavity is 1501.8 m. With increasing pump power, the pulse duration can be tuned from 209.8 ns to 812.4 ns without wave-breaking, and the maximum output single pulse energy is 42.34 nJ. To the best of our knowledge, this is the widest pulse in any Yb-doped mode-locked fiber laser. Moreover, the relationship between pulse width and cavity length is investigated. When the total cavity length is decreased to 1001.8 m and 501.8 m, the tuning range of square pulse is 372.4 ns (from 58.6 ns to 431 ns) and 138 ns (from 26 ns to 164 ns), respectively, and the maximum output single pulse energy is 13.85 nJ and 8.75 nJ, respectively.

[Risk and solutions to chimeric antigen receptor-engineered T cell-based cancer immunotherapy].

The potential of cancer immunotherapy has been demonstrated recently using the chimeric antigen receptors-engineered (CAR) T cells, in which B cell haematological malignancies was successfully treated in clinical trials. However, challenges remain in the translation of the potential benefits into therapy of other types of cancer with similar efficacy and safety. Excessive activation of genetically-modified T cells may cause severe toxicities, such as cytokine storm, on-target toxicities, and tumor lysis syndrome. Genomic integration of viral vectors may cause genetic toxicities due to insertional mutagenesis of important genes. Strategies to overcome these toxicities are proposed and discussed, including the use of suicide genes, combinatorial antigen recognition, on-switch, non-viral vector and other innovative gene therapy strategies, to enhance safety of this promising immunotherapy.

[Anti-inflammatory effect of recombinant human kallistatin in ulcerative colitis of mice].

This study was designed to evaluate the anti-inflammatory effect of recombinant human kallistatin (Kal) on ulcerative colitis (UC) in the mouse model. Acute colitis was induced by administration of 4% dextran sodium suffate (DSS) to KM mice for 7 days. The mice were then randomized into 5 groups: model control, Kal 0.2 mg·kg(-1)·d(-1), 1.0 mg·kg(-1)·d(-1) and 2.0 mg·kg-1·d(-1) group, salazosulfapyridine (SASP) group. Ten age-matched normal KM mouse were administered with saline in the normal control. The weight, colon length, inflammation factor (MPO/SOD/MDA) and TNF-α/IL-10 levels among the five groups of mice were determined. The results showed that histological index score and MPO/MDA/TNF-α levels of high-dose Kal treatment group and SASP group were significantly lower compared with the model group (P < 0.01), but the weight, colon length, IL-10 level and SOD activity were significant higher than the model group (P < 0.01), approaching the normal group. These parameters showed that Kal can significantly relieve the UC state in a dose-dependent manner. This study demonstrates that Kal significantly remits UC in mice, and participates in the regulation of inflammatory cytokines TNF-α/IL-10 levels and has some antioxidant activity.

Multi-wavelength lasers with suppressed spectral linewidth of 10 kHz.

High coherent multi-wavelength or multi-tone light source are in high demand for optical density wavelength division multiplexed (DWDM) networks as the telecommunication capacity expands exponentially. However the linewidths of commercial multi-wavelength semiconductor lasers are typically a few MHz which is not acceptable when the frequency spacing of the multi-tones is 10 GHz. In this paper, a novel and simple method to suppress the linewidths of the multi-wavelength from ~6 MHz to ~10 kHz using an all-optical approach is proposed and demonstrated. The linewidths of the multi-wavelength are suppressed by a factor of 600 and the noise level of the multi-wavelength is decreased by nearly 20 dB. Each wavelength of the multi-wavelength operates in single longitudinal mode. Finally, more than 8 wavelengths over 10 nm are suppressed simultaneously through the approach and scheme presented in this work.

Plasmid mediated kallistain gene expression via intramuscular electroporation delivery in vivo for treatment of NCI-H446 subcutaneous xenograft tumor.

Kallistatin (KAL) is a novel anti-tumor protein with anti-angiogenic activity. The aim of this study was to investigate whether intramuscular injection of KAL plasmid DNA by electroporation could inhibit NCI-H446 subcutaneous xenograft tumor growth in mice. The tumor model of BALB/c nude mice was induced by subcutaneous inoculation of 5×10(6) NCI-H446 cells into the mice right flank. The next day, naked plasmid pEGFP or pKAL was electrotransfered into the skeletal muscle of nude mice (n=6 for each group), with the optimized electroporation conditions. Tumor cells migration was assessed by E-cadherin staining; Proliferation was determined by anti-Ki-67 staining; and apoptosis was assayed via TUNEL, tumor microvessel density (MVD) was examined by anti-CD34 staining to evaluate the angiogenesis of tumor. Compared to the pEGFP treating group, tumor growth was inhibited by 85% (pEGFP group: 486 ± 187 mm(3), pKAL group: 71±33 mm(3)) at day 42, the MVD of tumor tissues was significantly decreased, and tumor cellular proliferation was also inhibited. The results indicate that this therapeutic strategy might serve as a promising approach for cancer clinical therapy.

[Novel targets for antibiotics discovery: riboswitches].

Riboswitches are cis-acting domains located in mRNA sequences that could regulate gene expression by sensing small molecules without employing protein. Most known riboswitches in bacteria have naturally evolved to bind essential metabolite ligands and are involved in the regulation of critical genes that are responsible for the biosynthesis or transport of the cognate ligand. The riboswitch-mediated gene expression could be repressed by metabolite analogs, which caused bacterial growth inhibition or even death. A number of leading compounds targeting riboswitches have been discovered. A promising avenue for the development of new class of riboswitch-based antibiotics has been opened. Herein we reviewed the current findings of riboswitches that served as targets for antibacterial drug development and the underlying mechanisms. The development of high-throughput methods and rational drug design for riboswitch-specific drug discovery are relevant challenges are discussed. summarized.

Colon cancer diagnosis and staging classification based on machine learning and bioinformatics analysis.

Advanced metastasis of colon cancer makes it more difficult to treat colon cancer. Finding the markers of colon cancer (Colon Cancer) can diagnose the stage of cancer in time and improve the prognosis with timely treatment. This paper uses gene expression profiling data from The Cancer Genome Atlas (TCGA) for the diagnosis of colon cancer and its staging. In this study, we first selected the gene modules with the greatest correlation with cancer by Weighted Gene Co-expression Network Analysis (WGCNA), extracted the characteristic genes for differential expression results using the least absolute shrinkage and selection operator algorithm (Lasso) and performed survival analysis, and then combined the genes in the modules with the Lasso-extracted feature genes were combined to diagnose colon cancer versus healthy controls using RF, SVM and decision trees, and colon cancer staging was diagnosed using differentially expressed genes for each stage. Finally, Protein-Protein Interaction Networks (PPI) networks were done for 289 genes to identify clusters of aggregated proteins for survival analysis. Finally, the RF model had the best results in the diagnosis of colon cancer versus control group fold cross-validation with an average accuracy of 99.81%, F1 value reaching 0.9968, accuracy of 99.88%, and recall of 99.5%, and an average accuracy of 91.5%, F1 value reaching 0.7679, accuracy of 86.94%, and recall in the diagnosis of colon cancer stages I, II, III and IV. The recall rate reached 73.04%, and eight genes associated with colon cancer prognosis were identified for GCNT2, GLDN, SULT1B1, UGT2B15, PTGDR2, GPR15, BMP5 and CPT2.

Breast Cancer Case Identification Based on Deep Learning and Bioinformatics Analysis.

Mastering the molecular mechanism of breast cancer (BC) can provide an in-depth understanding of BC pathology. This study explored existing technologies for diagnosing BC, such as mammography, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET) and summarized the disadvantages of the existing cancer diagnosis. The purpose of this article is to use gene expression profiles of The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) to classify BC samples and normal samples. The method proposed in this article triumphs over some of the shortcomings of traditional diagnostic methods and can conduct BC diagnosis more rapidly with high sensitivity and have no radiation. This study first selected the genes most relevant to cancer through weighted gene co-expression network analysis (WGCNA) and differential expression analysis (DEA). Then it used the protein-protein interaction (PPI) network to screen 23 hub genes. Finally, it used the support vector machine (SVM), decision tree (DT), Bayesian network (BN), artificial neural network (ANN), convolutional neural network CNN-LeNet and CNN-AlexNet to process the expression levels of 23 hub genes. For gene expression profiles, the ANN model has the best performance in the classification of cancer samples. The ten-time average accuracy is 97.36% (±0.34%), the F1 value is 0.8535 (±0.0260), the sensitivity is 98.32% (±0.32%), the specificity is 89.59% (±3.53%) and the AUC is 0.99. In summary, this method effectively classifies cancer samples and normal samples and provides reasonable new ideas for the early diagnosis of cancer in the future.

[Studies on correspondence between catalytic activity and fluorescence spectra character of macrocyclic dioxotetramine complexes].

In this paper, the conventional fluorescence spectra and laser induced fluorescence spectra of a novel macrocyclic dioxotetramine, 1,4,7,10-tetraazacyclotridecane-11,13-dionato and its Cu(II), Co(II), Ni(II) complexes at different pH are studied. The results show that the complexes fluorescence quantum yields have the relation of phi CuL5 < phi CoL5 < phi NiL5. At the same time, the reasonable explanation is given. The correspondence between their catalytic activities and fluorescence spectra character as minic superoxide dismutase metalloenzynes are also analyzed. It has been found that the fluorescence quantum yield of CuL5 decreases when the pH gets higher. But it is on the contrary for CoL5 and NiL5. It has been inferred that catalytic activities may be CuL5 > CoL5 > NiL5 according to their fluorescence quantum yield.

[Expression of human long-acting FSH in CHO cell and its bioactivity in vivo].

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein hormone that is essential for the development of ovarian follicles and testicular seminiferous tubules. The relatively short half-life of FSH in vivo requires daily injections for more than 10 days that is inconvenient and possibly contribute to the stress perceived by the patients. The goal of the present study was to increase FSH glycosylation, in order to develop a long-acting recombinant FSH. The cDNA of native alpha and beta subunit of human FSH was linked by a sequence with two N-linked glycosylation sites, and the resulted DNA was inserted into pcDNA3.1 vector to generate a recombinant vector of pcDNA3.1-FSH. The pcDNA3.1-FSH was linearized and transfected into CHO-K1, positive transformants were selected by G418 and confirmed by PCR and Western blotting. A single chain recombinant FSH was expressed, with molecular weight of about 49 kDa. The recombinant FSH expression level in CHO-K1 cell strain in serum-free culture was 3 mg/L. Single injection of this recombinant FSH could induce folliculogenesis and ovulation in rats, the efficacy was similar with the commercially available FSH preparation (Folltropin-V) administrated 8 times consecutively. The results suggested a long-acting FSH was produced successfully.