Molecular epidemiology and antimicrobial resistance of outbreaks of Klebsiella pneumoniae clinical mastitis in Chinese dairy farms

Klebsiella pneumoniae is an opportunistic pathogen that causes serious infections in humans and animals. However, the availability of epidemiological information on clinical mastitis due to K. pneumoniae is limited. To acquire new information regarding K. pneumoniae mastitis, data were mined about K. pneumoniae strains on dairy cattle farms (farms A to H) in 7 Chinese provinces in 2021. Hypermucoviscous strains of K. pneumoniae were obtained by the string test. MICs of antimicrobial agents were determined via the broth microdilution method. Ten antimicrobial resistance genes and virulence genes were identified by PCR. The prevalence of K. pneumoniae was 35.91% (65/181), and 100% of the bacteria were sensitive to enrofloxacin. Nine antimicrobial resistance genes and virulence genes were identified and compared among farms. The hypermucoviscous phenotype was present in 94.44% of isolates from farm B, which may be a function of the rmpA virulence gene. Based on these data, the multidrug-resistant strains SD-14 and HB-21 were chosen and sequenced. Genotypes were assayed for K. pneumoniae isolates from different countries and different hosts using multilocus sequence typing (MLST). Ninety-four sequence types (STs) were found, and 6 STs present a risk for spreading in specific regions. Interestingly, ST43 was observed in bovine isolates for the first time. Our study partially reveals the current distribution characteristics of bovine K. pneumoniae in China and may provide a theoretical basis for the prevention and treatment of bovine K. pneumoniae mastitis

Boosting with an aerosolized Ad5-nCoV elicited robust immune responses in inactivated COVID-19 vaccines recipients

IntroductionThe SARS-CoV-2 Omicron variant has become the dominant SARS-CoV-2 variant and exhibits immune escape to current COVID-19 vaccines, the further boosting strategies are required.MethodsWe have conducted a non-randomized, open-label and parallel-controlled phase 4 trial to evaluate the magnitude and longevity of immune responses to booster vaccination with intramuscular adenovirus vectored vaccine (Ad5-nCoV), aerosolized Ad5-nCoV, a recombinant protein subunit vaccine (ZF2001) or homologous inactivated vaccine (CoronaVac) in those who received two doses of inactivated COVID-19 vaccines. ResultsThe aerosolized Ad5-nCoV induced the most robust and long-lasting neutralizing activity against Omicron variant and IFNg T-cell response among all the boosters, with a distinct mucosal immune response. SARS-CoV-2-specific mucosal IgA response was substantially generated in subjects boosted with the aerosolized Ad5-nCoV at day 14 post-vaccination. At month 6, participants boosted with the aerosolized Ad5-nCoV had remarkably higher median titer and seroconversion of the Omicron BA.4/5-specific neutralizing antibody than those who received other boosters. DiscussionOur findings suggest that aerosolized Ad5-nCoV may provide an efficient alternative in response to the spread of the Omicron BA.4/5 variant.Clinical trial registrationhttps://www.chictr.org.cn/showproj.html?proj=152729, identifier ChiCTR2200057278

Intelligent Island detection method of DC microgrid based on Adaboost algorithm

Aiming at the problems of large detection blind areas and difficult threshold settings in traditional passive islanding detection methods, this paper proposes an intelligent passive islanding detection method based on the adaptive boosting (Adaboost) algorithm. This method first uses feature screening technology to obtain the key feature electrical quantities of DC microgrid islands and form a sample set, and then rely on the Adaboost algorithm to generate a high-precision island classification model to realize the detection and classification of DC microgrid operation status. It has the advantages of automatic setting threshold, small detection blind area, and high accuracy. In addition, aiming at the problem that the classification results of the intelligent islanding detection algorithm based on machine learning cannot be directly used as the islanding discrimination results, an islanding criterion method based on the sliding window algorithm is added on the basis of the classification algorithm. This method realizes the accurate detection of the DC microgrid islanding operation state by the secondary analysis and judgment of the classification results of the islanding classification model. Finally, a DC microgrid model is built to simulate and verify the proposed method. The results show that the method can quickly and accurately complete the islanding detection of the DC microgrid

Effects of Cr and Mo elements on the microstructures and compressive properties of the in situ (TiCxNy–TiB2)/Ni cermets

In-situ (TiCxNy–TiB2)/Ni cermets with 70 wt% TiCxNy–TiB2 were successfully fabricated by combustion synthesis and hot pressing sintering in Ni-Ti-B4C-BN powder systems. The microstructures, density, compressive properties, and hardness of the TiCxNy–TiB2/Ni cermets with the addition of 0–8 wt% Cr/Mo to the Ni-Ti-B4C-BN powder systems were compared and analysed. The results showed that the ceramic particles distributed uniformly in the cermets, and the size of the ceramic particles reduced with the Cr/Mo addition. Both Cr and Mo addition can improve the hardness, compressive properties, and fracture strains of the cermets. The hardness, compressive strength, and fracture strain of the (TiCxNy–TiB2)/(Ni+Cr) cermets increased from 1561 HV, 2.94 GPa, and 2.9% to 1864 HV, 3.65 GPa, and 3.4%, respectively when the Cr content increased to 5 wt%. The hardness and compressive strength of the (TiCxNy–TiB2)/(Ni+Mo) cermets increased from 1561 HV and 2.94 GPa to 1902 HV and 3.43 GPa, respectively when the Mo content increased to 8 wt%. The cermets with Cr had better compressive properties than the cermets with Mo. Keywords: (TiCxNy–TiB2)/Ni cermets, Cr/Mo content, Microstructure, Compressive propertie

Effects of V and Co Element Addition on Microstructures and the Mechanical Properties of In Situ Biphasic Hybrid (TiCxNy–TiB2)/Ni Cermets

In situ micro-(TiCxNy–TiB2)/Ni cermets with different Co and V content (2,5 and 8 wt.%) were successfully fabricated by combustion synthesis and hot press consolidation in Ni–(V/Co)–Ti–B4C–BN systems. The results indicate that as Co content increased from 0 to 8 wt.%, the average sizes of the ceramic particles decreased, when the content of V increased from 0 to 8 wt.%, the size of the ceramic particles first decreased and then increased, and when the V content is 5%, the ceramic particle size is the smallest. The Co element did not participate in the SHS reaction and was a diluent; therefore, when the Co element was added, the combustion temperature continued to decrease. When the V content was no more than 5 wt.%, as the V content increased, the maximum combustion temperature decreased. When the content of V was less than 5 wt.%, the concentration of V was not sufficient to greatly promote the generation of VN. Therefore, V absorbed a large amount of heat during the reaction, resulting in a continuous decrease in the reaction temperature of the reaction system during the reaction. When the content of the added V continued to increase to 8 wt.%, V participated in the reaction, which was exothermic. The results indicate that as Co content increased from 0 to 8 wt.%, the average sizes of the ceramic particles decreased, and the cermets with 5 wt.% Co possessed the best comprehensive properties: the highest hardness (1967 Hv), superior compression strength (3.25 GPa) and higher fracture strain (3.3%). Correspondingly, when the V content was 8 wt.%, the ultimate compressive strength and hardness of the cermets reached 1823 Hv and 3.11 GPa, respectively, 262 Hv and 0.17 GPa higher than those of the unalloyed cermets, respectively. Furthermore, the effects of Co and V on strengthening mechanisms were analyzed

Coherent Random-Modulated Continuous-Wave LiDAR Based on Phase-Coded Subcarrier Modulation

A coherent random-modulated continuous-wave (RMCW) LiDAR transmits a lightwave modulated by a pseudo-random binary sequence (PRBS). The lightwave backscattered from targets is received and used to reconstruct the PRBS. Then, the time-of-flight is extracted by correlating the reconstructed PRBS and the original PRBS. We propose a coherent RMCW LiDAR based on phase-coded subcarrier modulation, in which the impacts of internal reflection and optical Doppler frequency shift (DFS) are mitigated. A continuous lightwave is amplitude-modulated by an RF signal which is phase-coded with a PRBS. Coherent detection is used in the receiver. A beat signal that consisted of a low-frequency signal and a high-frequency signal is obtained by a single balanced photodetector (BPD). The optical DFS can be directly extracted from the low-frequency signal. It is used to compensate for the frequency offset of PRBS, which is extracted from the high-frequency signal. In addition, the background noise caused by internal reflection is suppressed by averaging over successive measurement spots. In this paper, the performance of a coherent RMCW LiDAR is firstly analyzed by numeric simulations and demonstration experiments. Then, line-scanning measurements for moving targets are implemented to demonstrate the 3D imaging capability of the proposed coherent RMCW LiDAR

The effects and gender-related differences of guided forest therapy program on physiological and psychological health of graduating college students

Forest therapy has been proven to have a quantifiable positive impact on human physiological and psychological health. Given that graduating students at university are easy to stress due to changes in life, pressure from their studies, and independence in finance. The main purpose of this research was to explore the effects of guided forest therapy on graduating college students through a field experiment in Pacific Spirit Regional Park which held significant geographical value. This paper investigated the pressure of graduating college students and their needs for forest therapy, and explored the psychological and physiological changes after guided forest therapy. This study also analyzed gender-related psychological and physiological differences. Thirty-six healthy graduating college students were invited to participate in a 2-hour forest therapy program. Likert scales were used to assess students' pressure and the demand for forest therapy. Most of the students were facing the pressure of graduation and were willing to participate in forest therapy. Systolic and diastolic blood pressure, pulse rate, and heart rate variability (HRV) were used as physiological measurement indices. Our physiological results indicated that blood pressure significantly decreased, the high-frequency component of HRV (HF) was significantly larger, and the low-to-high-frequency component ratio (LF/HF) was smaller after the forest therapy program, and some beneficial changes in females were more significant than that in males. The participants' mean HR decreased throughout the forest therapy, but there were no significant differences. Mental status was assessed before and after forest therapy using the Profile of Mood States (POMS), employment stress scale and State-Trait Anxiety Inventory (STAI) for participants. Overall, the guided forest therapy program effectively reduced participants' employment stress and state anxiety. Our research showed that guided forest therapy had positive physiological and psychological benefits for graduating college students. In addition, females obtained more positive physiological benefits than males, and males obtained more positive psychological benefits than females throughout forest therapy

Impact of closed management on gastrointestinal function and mental health of Chinese university students during COVID-19

Abstract Background The innovative closed management of universities may have influenced the physical and mental health of students during the fourth stage of the COVID-19 pandemic in China. The study aimed to assess the gastrointestinal and mental health status of students in this stage and to explore the possible risk factors and mechanisms to provide a reference for future school responses to similar stressful events. Method A multicenter, cross-sectional survey was administered to 598 college students from 10 Chinese universities. The study used the 7-item Generalized Anxiety Disorder Scale (GAD-7), 9-item Patient Health Questionnaire (PHQ-9), Fear of COVID-19 Scale (FCV-19 S), and the Diagnostic Tendency of Functional Bowel Disease Scale (DT-FBD) to evaluate anxiety, depression, fear of COVID-19 and likelihood of being diagnose diagnosed with functional bowel disease (FBD), respectively. Results A total of 516 college students completed the questionnaire. The proportions of students with more severe anxiety, more severe depression, greater fear of COVID-19, and a greater likelihood of being diagnosed with FBD were 49.8%, 57.0%, 49%, and 49%, respectively. These symptoms were significantly and positively correlated with the frequency of irregular sleep and eating (p < 0.05). Students in high-risk areas were more likely to experience anxiety and depression than students in areas with low/medium risk (odds ratio [OR] = 1.90, 95% confidence interval [CI]: 1.12–3.24, p = 0.017; OR = 2.14, 95% CI: 1.11–4.11, p = 0.022). A high likelihood of being diagnosed with FBD was positively associated with the severity of anxiety and depression symptoms and fear of COVID-19 (all p < 0.001). Moreover, mediation analysis revealed the following pathway in college students: fear of COVID-19 → depression and anxiety → poor diet → likelihood of being diagnosed with FBD. Conclusion College students generally exhibited higher more severe anxiety and depression symptoms and psychological symptoms with a greater higher propensity likelihood of being to be diagnosed with FBD. Good lifestyle habits, especially adequate sleep and a regular diet, can alleviate these problems. In addition, appropriate psychological intervention is very important