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Ping Yang,1,2 Chao Liu,3 Zhenchao Wu,2 Jiajia Zheng,4 Juan Yi,1 Nan Wu,2 Zhangli Wu,1,2 Ming Lu,2,3 Liyan Cui,4,&ast; Ning Shen1– 3,&ast; 1Institute of Medical Technology, Peking University Health Science Center, Beijing, People’s Republic of China; 2Department of Pulmonary and Critical Care Medicine, Peking University Third Hospital, Beijing, People’s Republic of China; 3Department of Infectious Diseases, Peking University Third Hospital, Beijing, People’s Republic of China; 4Department of Laboratory Medicine, Peking University Third Hospital, Beijing, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Liyan Cui; Ning Shen, Email cliyan@163.com; shenningputh@163.comPurpose: This study aimed to identify the clinical outcomes, microbiological features and risk factors for difficult-to-treat resistance (DTR) Klebsiella pneumoniae (Kp) infection.Materials and Methods: A retrospective study was conducted at Peking University Third Hospital from January 2020 to March 2021. DTR was defined as resistance to ≥ 1 carbapenem, ≥ 1 extended-spectrum cephalosporin, and ≥ 1 fluoroquinolone. Hypervirulent Kp (HvKp) was defined as peg-344-, iroB-, iucA-, rmpA-, or rmpA2-positive. Clinical data were collected. Antimicrobial susceptibility testing and string tests were performed to determine resistance and hypermucoviscosity phenotype. Whole genome sequencing was performed to analyze the sequence type (ST), capsular serotypes, resistance and virulence genes. Risk factors for 30-day mortality were analyzed.Results: Fifty DTR-Kp (50.0%) strains were identified among 100 patients. Compared to non-DTR-Kp group, a significant number of patients with DTR-Kp infection experienced ICU admission (44.0% versus 10.0%, P< 0.001) and mechanical ventilation after Kp detection (26.0% versus 10.0%, P=0.037). Notably, the percentage of hvKp among the DTR-Kp isolates increased consistently over the 15 months evaluated. Most DTR-Kp strains belonged to ST11 (82.0%), followed by ST15 (12.0%), ST86 (2.0%), ST996 (2.0%), and ST3157 (2.0%). DTR-Kp isolates possessed various resistance genes, such as blaKPC-2, blaTEM-1D and fosA3 (90.0%, 80.0% and 72.0%, respectively). Importantly, the yersiniabactin genes were significantly clustered in DTR group (48/50, 96.0%). The 30-day mortality was significantly higher in patients with DTR-Kp infection than non-DTR-Kp group (38.0% versus 8.2%, P=0.001). DTR-Kp infection (odds ratio [OR] = 4.196) was an independent risk factor for the 30-day mortality of Kp-infected patients. Additionally, cerebrovascular disease (OR = 2.780) and Charlson comorbidity index (OR= 1.584) were independent risk factors for DTR-Kp infections.Conclusion: DTR-hvKp is rapidly emerging. The DTR-Kp strains harbored various resistance genes and high rates of yersiniabactin siderophore genes. DTR-Kp infection was an independent risk factor for mortality, suggesting that enhanced awareness essential.Keywords: Klebsiella pneumoniae, difficult-to-treat resistance, mortality, risk factor

Optical fiber microresonators have attracted considerable interest for acoustic detection because of their compact size and high optical quality. Here, we have proposed, designed, and fabricated a spring-based Fabry–Pérot cavity microresonator for highly sensitive acoustic detection. We observed two resonator vibration modes: one relating to the spring vibration state and the other determined by the point-clamped circular plate vibration mode. We found that the vibration modes can be coupled and optimized by changing the structure size. The proposed resonator is directly 3D printed on an optical fiber tip through two-photon polymerization and is used for acoustic detection and imaging. The experiments show that the device exhibits a high sensitivity and low noise equivalent acoustic signal level of 2.39 mPa/Hz1/2 at 75 kHz that can detect weak acoustic waves, which can be used for underwater object imaging. The results demonstrate that the proposed work has great potential in acoustic detection and biomedical imaging applications.

The all-optical fiber-based intelligent sensing system is one key technology for acoustic/ultrasonic structural health monitoring. Damages such as cracking or impact loading in civil, aerospace, and mechanical structures can generate transient ultrasonic waves, which can reveal the structural health condition. Hence, there is a great need to develop a high precision adaptive sensor for large-value strain signals with large frequency range that can extent to several hundred kilohertz in ultrasonic/acoustic sensing. In this work, we explore an intelligent system based on a fiber Bragg grating (FBG) and an erbium-doped fiber amplifier (EDFA), composing as a fiber cavity that offers significant advantages and higher performance in ultrasonic/acoustic sensing applications. The ASE light emitted from the EDFA and reflected by a FBG is amplified in the fiber cavity and coupled out by a 90:10 coupler, which is demodulated by an unbalanced Mach-Zehnder interferometer (MZI) composed by a 2×2 coupler and a 3×3 coupler. As the reflective spectrum of the FBG sensor changes due to excited acoustic waves, the shift of the laser output wavelength is subsequently converted into a corresponding phase change. We theoretically and experimentally calculate the three output signals using a differential cross-multiplication (DCM) algorithm to directly demodulate the wavelength shift of the FBG sensor. The experimental results demonstrate that the proposed FBG acoustic sensing system has high sensitivity and can respond the ultrasonic waves into the hundreds of kilohertz frequency range, which shows a potential for acoustic emission detection in practical applications.

Continuous fiber laser with ultra-high power and narrow linewidth is one of the key devices in the field of high-precision industrial processing, beam combining, and nonlinear frequency conversion. Under the premise of ensuring the signal quality, continuously increasing the output power is the focus of high-power narrow-linewidth fiber lasers. Driven by the white noise or pseudo-random binary sequence (PRBS), using cascaded phase modulations to broaden the spectrum of the seed source to suppress the stimulated Brillouin scattering (SBS) effect in the master oscillator power amplifier (MOPA) structure is an effective solution to increase the output power. However, this type of optical spectrum needs to be optimized, and the randomness of the driving signal causes a self-pulsing effect, which limits the further increase of the output power. In this paper, the influence of the frequency interval and randomness of the driving signal on the SBS effect in the laser system is analyzed. The modulated spectral type can be simply adjusted through changing the bit rate and inversion probability. Combining with high-order phase modulation, an approximate rectangular spectral broadening of the seed source with a tunable bandwidth up to 30 GHz is achieved. Compared with the cascaded white noise case, the output power of this scheme is increased by 600 W under the extended bandwidth of 27 GHz. It is fully verified that the seed source spectrum with high in-band flatness and low randomness can effectively suppress the SBS effect in the fiber laser and increase the output power.

Poor soil hydraulic properties (SPH) limit the productivity of clayey Utisol (red soil) under a humid subtropical climate in southern China. The roots performance of rotation crops was compared, and the effects on SPH were investigated in the field. Five treatments (two cultivars of oilseed rape, one-year-old lucerne, and one- and five-year-old vetiver) were employed as pre-crops before summer maize, and their root performances were examined in spring. The soil-water characteristic curve (SWCC) and soil porosity were measured with soil cores, saturated hydraulic conductivity (Ks), and near-saturated hydraulic conductivity with a tension infiltrometer in situ. The two rape cultivars had the thinnest root diameter at an average of 0.45−0.50 mm and the shallowest distribution at a depth of 40 cm, while two vetivers had the thickest mean root diameter at 0.79 mm and the deepest distribution >80 cm. Taproot crops of rape and lucerne did not show stronger rooting ability than fibrous root crops of vetivers. All crops increased soil total and aeration porosity, but no bio-pores larger than 2 mm were formed. Rapes were beneficial for increasing soil aeration porosity (diameter >30 μm), while vetivers increased active capillary porosity (30−0.2 μm). The SHP, namely, SWCC and Ks, was improved by all crops, with the best effects in the five-year old vetiver due to its higher root length density (RLD) and the balanced distribution between diameter classes. Ks was significantly correlated with RLD (p