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Foodborne pathogens and biofilm formation pose a critical threat to food safety. Pseudomonas aeruginosa is a pathogen of interest in the food industry. High-power pulsed microwave (HPPM) is a non-thermal technology with proven efficacy towards bacterial inactivation. This study investigated the inactivation mechanisms and performance of different HPPM treatments (50, 100, 150, 200, and 250 Hz for 3, 5, 7, 9, and 11 min, respectively) to identify the optimum conditions to inactivate P. aeruginosa PAO1 biofilms. The results showed significant cell inactivation at increasing frequency/time (p < 0.05). Hence, HPPM treatment (200 Hz, 9 min) was selected following its efficacy and limited thermal sublethal effects to elucidate further the inactivation mechanisms against P. aeruginosa and its biofilm-forming ability. Cell viability, scanning (SEM) and transmission electron microscopy (TEM) results demonstrated severe morphological disruptions, cell disintegration, and cell lysis in the treated cells. From the confocal laser scanning micrographs (CLSM), biofilm thickness was calculated, showing a significant reduction after treatment (17.56 vs. 42.16 μm in the treated and untreated groups, respectively), indicating that HPPM effectively compromised the integrity of the biofilm envelope. This study outlines useful insights into better understanding HPPM's efficacy on microbial inactivation and biofilm proliferation in the food industry. • High-power pulse microwave (HPPM) demonstrated significant cell inactivation at increasing frequency/time (p < 0.05). • Treated cells demonstrated severe cell deformation, membrane shriveling, and cell lysis. • It showed a marked reduction in biofilm thickness than untreated cells (17.56 ± 1.51vs. 42.16 ± 1.23 μm). • This study provides useful insights into validating HPPM's efficacy against bacterial biofilm formation. [ABSTRACT FROM AUTHOR]

Opioid withdrawal generates extremely unpleasant physical symptoms and negative affective states. A rapid relief of opioid withdrawal-induced anxiety has obvious clinical relevance but has been rarely reported. We have shown that injection of ketamine metabolite (2 R ,6 R)-hydroxynorketamine (HNK) leads to a rapid alleviation of anxiety-like behaviors in male mice undergoing chronic morphine withdrawal. Here we investigated the contribution of nucleus accumbens shell (sNAc) parvalbumin (PV)-neurons to this process. Chronic morphine withdrawal was associated with higher intrinsic excitability of sNAc PV-neurons via reduced voltage-dependent potassium currents. Chemogenetic inhibition of sNAc PV-neurons reversed the enhanced excitability of PV-neurons and anxiety-like behaviors in these morphine withdrawal male mice, while activation of sNAc PV-neurons induced anxiety-like behaviors in naive male mice. (2 R ,6 R)-HNK reversed the altered potassium currents and intrinsic excitability of sNAc PV-neurons. Our findings demonstrate an important contribution of sNAc PV-neurons to modulating morphine withdrawal-induced anxiety-like behaviors and rapid relief of anxiety-like behaviors by (2 R ,6 R)-HNK, this newly identified target may have therapeutic potentials in treating opioid addiction and anxiety disorders. • sNAc PV-neuron excitability is higher in mice undergoing morphine withdrawal. • Inhibiting sNAc PV-neurons improves morphine withdrawal-induced anxiety-like behaviors. • Activating sNAc PV-neurons elicits anxiety-like behaviors in naïve mice. • (2 R ,6 R)-HNK alleviates morphine withdrawal-induced anxiety-like behaviors in mice. • (2 R ,6 R)-HNK increases K+ currents and reduces excitability of sNAc PV-neurons. [ABSTRACT FROM AUTHOR]

• An improved dynamic model of ball bearing is proposed. • This model considers bearing deformations and ball-inner raceway separation. • A prediction method for the initial values is applied to solve dynamic model. • The influence of deformations and ball-inner raceway separation is discussed. In actual operation conditions, the bearing deformations caused by the change of assembly state play a major role in bearing dynamic performance, and the ball-inner raceway separation due to the insufficient preload or excessive external loads is also a key issue that limits the bearing service. In this paper, an improved nonlinear dynamic model of ball bearing considering bearing deformations and ball-inner raceway separation is proposed. Firstly, the relationships between the bearing deformations and bearing-shaft assembly state are directly derived according to the deformation compatibility condition, and the interaction and relative motions among various bearing components under the ball-inner raceway separation conditions are analyzed. Then a prediction method for the initial iterative values is used to calculate the dynamic model, and the calculation results are compared with the experimental data for verification. Finally, the variations of bearing deformations, contact properties, and cage skid under different factors are investigated. It is found that the bearing deformations affect the contact properties of ball-raceway, and the appropriate preload effectively improves the bearing service characteristics, especially under the ball-inner raceway separation conditions. [ABSTRACT FROM AUTHOR]

• A 5 DOFs nonlinear dynamics model of four-point contact ball bearing was proposed. • The dynamic contact feature of FCPBB with complex operating conditions were investigated. • The interaction between balls and raceway may changes from 2-point to 3-point contact with pure axial load. • The ball may experience 2-point contact, 3-point contact and 4-point contact in one revolution in case of combined loads. Four-contact-point ball bearing (FCPBB), with a special double half inner ring structure, presents dynamic multi-point contact characteristics in service. The dynamic contact feature, such as 2-point, 3-point or even 4-point contact phenomena between balls and bearing raceway, lead to completely different bearing friction, heat generation and wear rates. Considering the oil film traction effect, the traction and contact equations for ball and four raceways were proposed, and the changes of bearing dynamic contact feature with complex operating conditions, such as high speed-slight load, combined axial-radial load, were investigated. As bearing preload increases, the interaction between the ball and raceway gradually changes from 3-point to 2-point contact. In this process, the PV factor in outer sub-contact area first increases and then decreases, which is the key factor in bearing friction loss. In case of combined load, the ball may experience 2-point contact, 3-point contact and 4-point contact in one revolution. Besides, when two-point contact occurs, the main-contact area has the largest PV value; when four-point contact occurs, the sub-contact area has the largest PV value. [ABSTRACT FROM AUTHOR]