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The interrupted sampling repeater jamming (ISRJ) is a type of coherent jamming that can not only improve the detection threshold of adjacent range cells but also induce the radar system to track a false target. In order to suppress ISRJ, we have developed an interference identification and suppression method based on a clustering algorithm. First, we obtain the time-frequency (TF) domain matrix by applying the short-time Fourier transform (STFT) to the received signal containing the target echo and ISRJ. Then, the time-frequency domain matrix is subjected to threshold decision to obtain a series of over-threshold points which are then processed by the density-based spatial clustering of applications with noise (DBSCAN) algorithm to form a series of clusters. By analyzing the number of points of these clusters, we can identify whether the cluster corresponds to the target echo or ISRJ. Recognition mainly depends on the number of cluster points and the corresponding point threshold allowing for good recognition without the need for accurate estimation of ISRJ parameters. An accurate time-frequency domain filter is constructed based on the recognition results to avoid damaging the spectral structure of the target echo while suppressing the interference. We simulate the method and verify the effect of different combinations of input signal to noise ratio (SNR) and input signal to jamming ratio (SJR) on the performance of the method through Monte Carlo simulation. The simulation results demonstrate that this method has a good suppression effect for the three ISRJ modes under various combinations of SNR and SJR.

Background and Purpose: Chronic obstructive pulmonary disease (COPD) is proposed to hasten lung aging. Erythromycin protects against oxidative stress and inflammatory responses. However, the potential anti-senescence effect of erythromycin remains disclosed. In the present study, we investigated whether erythromycin influenced oxidative stress-induced cellular senescence and investigated its related mechanisms.Methods: A cigarrete smoke (CS) -induced emphysema mouse model and a H2O2-induced premature senescence model in human bronchial epithelial cell line (BEAS-2B) were established. Senescence-related markers (P53, P21 and SA-β-Gal activity), and levels of oxidative stress biomarkers (MDA, SOD and ROS) were measured. Additionally, cells were pretreated with rapamycin (mTOR inhibitor) or erythromycin, and the expression levels of components of the PI3K-mTOR signaling pathway were measured in BEAS-2B cells.Results: Exposed to H2O2, increased SA-β-gal activity was observed in BEAS-2B cells suggesting premature senescence. Erythromycin inhibited the expression of P53 and P21 in the CS-induced emphysema mouse model. MDA levels significantly increased and SOD levels decreased in the CS-exposed mice and H2O2-induced BEAS-2B cells. Rapamycin and erythromycin significantly suppressed the expression of P53 and P21. Additionally, rapamycin and erythromycin inhibited the PI3K-mTOR signaling pathway.Conclusion: Our findings suggest that erythromycin ameliorates oxidative stress-induced cellular senescence via the PI3K-mTOR signaling pathway. Hence, we establish a theoretical foundation for the clinical application of erythromycin for COPD prevention and treatment.

Primary amoebic meningoencephalitis (PAM) caused by Naegleria fowleri is a fatal infection with a mortality rate of more than 95%, despite advances in antimicrobial chemotherapy and supportive care. Initial manifestations of PAM are indistinguishable from bacterial meningitis. Prompt diagnosis and antifungal treatment may help decline the overall mortality. Here we present a case of a 38-year-old man transferred to our hospital due to mild headache, which deteriorated quickly. Severe increased intracranial pressure was found. The cerebrospinal fluid (CSF) was yellowish with significantly increased leukocyte and protein. Smear and culture were negative. The patient was first diagnosed with pyogenic meningoencephalitis. However, the symptoms deteriorated. Metagenomic next-generation sequencing (mNGS) of CSF was applied and finally confirmed N. fowleri as the protist pathogen within 24 h. However, due to the time cost of sampling and transportation (2 days), the diagnosis came too late, and the patient passed away 1 day before. In summary, mNGS is a rapid and accurate diagnostic method for clinical practices, especially for rare central nervous system infections. It should be used as quickly as possible for acute infections, such as PAM. All aspects of patient interrogation and prompt identification should be paramount to ensure appropriate treatment and decline the overall mortality.

Previous studies have reported that miR-27a-3p is down-regulated in the serum of patients with intracerebral hemorrhage (ICH), but the implication of miR-27a-3p down-regulation in post-ICH complications remains elusive. Here we verified miR-27a-3p levels in the serum of ICH patients by real-time PCR and observed that miR-27a-3p is also significantly reduced in the serum of these patients. We then further investigated the effect of miR-27a-3p on post-ICH complications by intraventricular administration of a miR-27a-3p mimic in rats with collagenase-induced ICH. We found that the hemorrhage markedly reduced miR-27a-3p levels in the hematoma, perihematomal tissue, and serum and that intracerebroventricular administration of the miR-27a-3p mimic alleviated behavioral deficits 24 h after ICH. Moreover, ICH-induced brain edema, vascular leakage, and leukocyte infiltration were also attenuated by this mimic. Of note, miR-27a-3p mimic treatment also inhibited neuronal apoptosis and microglia activation in the perihematomal zone. We further observed that the miR-27a-3p mimic suppressed the up-regulation of aquaporin-11 (AQP11) in the perihematomal area and in rat brain microvascular endothelial cells (BMECs). Moreover, miR-27a-3p down-regulation increased BMEC monolayer permeability and impaired BMEC proliferation and migration. In conclusion, miR-27a-3p down-regulation contributes to brain edema, blood-brain barrier disruption, neuron loss, and neurological deficits following ICH. We conclude that application of exogenous miR-27a-3p may protect against post-ICH complications by targeting AQP11 in the capillary endothelial cells of the brain.

Introduction: Although long-term macrolide antibiotics could reduce the recurrent exacerbation of chronic obstructive pulmonary disease (COPD), the side effect of bacterial resistance and the impact on the microbiota remain concerning. We investigated the influence of long-term erythromycin treatment on the airway and gut microbiota in mice with emphysema and patients with COPD. Methods: We conducted 16S rRNA gene sequencing to explore the effect of erythromycin treatment on the lung and gut microbiota in mice with emphysema. Liquid chromatography-mass spectrometry was used for lung metabolomics. A randomized controlled trial was performed to investigate the effect of 48-week erythromycin treatment on the airway and gut microbiota in COPD patients. Results: The mouse lung and gut microbiota were disrupted after cigarette smoke exposure. Erythromycin treatment depleted harmful bacteria and altered lung metabolism. Erythromycin treatment did not alter airway or gut microbial diversity in COPD patients. It reduced the abundance of pathogens, such as Burkholderia, in the airway of COPD patients and increased levels of symbiotic bacteria, such as Prevotella and Veillonella. The proportions of Blautia, Ruminococcus, and Lachnospiraceae in the gut were increased in COPD patients after erythromycin treatment. The time to the first exacerbation following treatment was significantly longer in the erythromycin treatment group than in the COPD group. Conclusion: Long-term erythromycin treatment reduces airway and gut microbe abundance in COPD patients but does not affect microbial diversity and restores microbiota balance in COPD patients by reducing the abundance of pathogenic bacteria. [ABSTRACT FROM AUTHOR]