The influence of different load distribution considering geometric error on the fatigue life of ball screw.

The ball screw pair is a precision drive component that converts rotary motion into linear motion. In practical applications, because the feed system usually has rotational torque and geometric errors, it may increase the contact load of the ball screw pair and reduce the fatigue life. In order to study the influence of different loads and geometric errors on the maximum contact load and fatigue life of ball screw pairs, the following research work was carried out. Firstly, based on the composite load and rotational torque, the ball load distribution model is established, and the accuracy of the model is verified by finite element modeling analysis. Then, the influence of different composite loads, rotation times and geometric errors (including ball size error, lead error and raceway tooth profile error) on the ball load distribution is analyzed. Finally, the influence of compound load, rotating torque and geometric error on the fatigue life of ball screw pairs is studied. The results show that the rotational torque and lead error have a great influence on the load distribution and fatigue life of the ball, and the influence of lead error on load distribution is greater than that of dimension error and tooth profile error. The fatigue life of the ball screw pair with non-uniform load distribution is shorter than that of the ball screw pair with uniform load distribution.

The efficacy of electroconvulsive therapy in adolescent major depressive disorder with suicidal ideation: A propensity score-matched, retrospective cohort study.

BACKGROUND: More evidence is needed to validate the use of ECT in adolescent depression. This study aims to compare the effectiveness of electroconvulsive therapy (ECT) to conventional medication therapy for adolescents with major depression with suicidal ideation. METHODS: In this retrospective cohort study, we reviewed inpatient records from the First Affiliated Hospital of Chongqing Medical University spanning December 2016 to June 2021. We focused on adolescents diagnosed with severe depression presenting with suicidal tendencies. To equalize baseline differences between patients, we used the one-to-one propensity score matching to match patients who received ECT treatment with those who did not. Multivariate regression analysis was utilized to adjust for potential confounders, and subgroup analyses and sensitivity analyses were conducted to verify the robustness of our findings. RESULTS: Of the 626 patients in this study, 474 underwent ECT treatment while 152 received medication treatment, all aged between 10 and 18 years. Once matched, each group contained 143 patients. The ECT group demonstrated a significantly higher response rate and greater reductions in both Hamilton Depression Rating Scale and Hamilton Anxiety Scale scores (all P < 0.001). Additionally, the ECT group was more effective in reducing suicidal ideation, with fewer individuals retaining such ideation at discharge. In the multivariable regression analysis, both ECT treatment and shorter disease duration were independently linked to enhanced antidepressant efficacy. Subgroup analyses and sensitivity analyses verified the robustness of the main study effect. CONCLUSIONS: For adolescents with major depressive disorder and suicidal ideation, combining ECT with pharmacotherapy is more effective than pharmacotherapy alone before medications reach full effect.

Electroconvulsive therapy for adolescents with severe depressive episode and suicidality: retrospective comparison between responders and non-responders.

BACKGROUND: For adolescents with major depression who exhibit suicidal tendencies, Electroconvulsive Therapy (ECT) is increasingly adopted in clinical practice. Yet, the precise mechanisms behind its effectiveness remain elusive, and studies on factors that influence treatment outcomes are scarce. METHODS: In this retrospective comparative study, we included all adolescent severe depressive episode patients with suicidal tendencies admitted to the Psychiatry Department of the First Affiliated Hospital of Chongqing Medical University between 2017 and 2021 and received ECT treatment. By collecting data on personal history, medical history, and standard treatment features, we established demographic, disease, medication, and ECT treatment factors variables. Patients were divided into effective and ineffective groups based on the Clinical Global Impressions-Improvement (CGI-I) scale scores, and differences between outcomes were compared. Logistic regression analyses were used to identify factors independently associated with ineffectiveness. RESULTS: A total of 494 adolescent severe depressive episode patients with suicidal behavior who received ECT were included in this study. According to CGI-I scores, the treatment was effective in 361 patients (73.1%) and ineffective in 133 patients (26.9%). Logistic regression analyses showed that 8 to 12 and 12 to 16 ECT sessions reduced the risk of ineffectiveness compared to fewer than 4 sessions. The risk of ineffectiveness decreased with age and increased with comorbidity with obsessive-compulsive disorder (OCD). Compared to sertraline, escitalopram was associated with a heightened risk of futility, whereas olanzapine and aripiprazole demonstrated a reduced risk when contrasted with quetiapine. CONCLUSIONS: ECT's ineffectiveness in treating adolescent severe depressive episode with suicidal behavior decreases with age, and comorbidity with OCD significantly increases the risk of treatment failure. Fewer than 8 ECT sessions may hinder achieving satisfactory results.

Efficient markerless gene deletions in Pseudomonas protegens Pf-5 using a upp-based counterselective system.

OBJECTIVES: Developing a counterselective system for efficient markerless gene deletions in biocontrol strain P. protegens Pf-5. RESULTS: We successfully implemented a markerless deletion of upp in Pf-5 to obtain the 5-FU resistant strain Pf5139. With this strain, we performed markerless gene deletions for each component of Gac/Rsm system and a 17 kb DNA fragment with the deletion ratio of 20 to 50%, and efficiently constructed a strain with triple deletions based on the suicide plasmid pJQ200UPP. In addition, there is no obvious connection between the deleted fragment length and the deletion ratio. CONCLUSION: The upp-based counterselective system in this study is efficient and valuable for markerless gene deletions in Pf-5, indicating that it has great potential in the study of gene function and in the application of genome reduction for Pseudomonas strains.

ArgR directly inhibits lipA transcription in Pseudomonas protegens Pf-5.

ArgR, a transcriptional regulator belonging to the AraC/XylS family, plays a key role in arginine metabolism regulation. ArgR has also been found to repress the transcription of a lipase gene, but its molecular mechanism is still unknown. In this study, we investigated the molecular mechanism acting on the expression of intracellular lipase gene lipA regulated by ArgR in Pseudomonas protegens Pf-5 through knockout and overexpression of argR, detection of DNA-protein interaction in vivo, determining whole-cell lipase activities of various strains derived from Pf-5, and examining ß-galactosidase activities of various lacZ fusions. The results demonstrated that ArgR inhibits lipA expression at the transcriptional level. Further results showed that the inhibition of lipA transcription by ArgR is mediated by binding to the ArgR binding site of lipA promoter to produce steric hindrance, in which the common sequence, TGTCGC is crucial for the ArgR binding. Besides, arginine inhibits lipA expression in both wild-type and argR mutant, and shows a synergistic inhibition on lipA expression when combined with ArgR. To the best of our knowledge, this is the first report on ArgR directly repressing the transcription of a lipase gene.

Characterization on the alternative splicing, expression and gene phylogenesis of PTPR4 family in Japanese flounder, Paralichthys olivaceus.

One mechanism of eukaryotic signaling is protein phosphorylation by protein tyrosine phosphatases (PTPs). Here we have identified the PTP Receptor-Type IV (PTPR4) family, including one form of PTPalpha and two forms of PTPepsilon (PTPepsilon M and PTPepsilon C) in flounder. The existence of PTPepsilon C has not been reported in non-mammalian animals. Semi-quantitative RT-PCR revealed independent expression patterns and levels of PTPalpha and the two forms of PTPepsilon in various tissues. The sequence of PTPepsilon C was identical to that of PTPepsilon M except for its 5'-terminal regions. Southern blot analysis proved that there existed only one PTPepsilon gene in flounder genome, indicating that the two isoforms of PTPepsilon might have been derived from alternative splicing of the single gene. Phylogenetic analysis of PTP domain D2 and part of D1 of PTPR4 showed that flounder was first joint with other teleost fish and then tetrapods, and also provided evidence that the gene duplication from the ancestor gene to PTPalpha and PTPepsilon occurred before the divergence of Gnathastomata and Agnatha. These results showed that the functional evolution of protein phosphorylation is promoted by not only genome duplication, but also elaborate regulation of gene expression.

Isolation and characterization of 64 novel microsatellite markers from a fosmid library of female half-smooth tongue sole (Cynoglossus semilaevis).

Microsatellite markers were developed from a fosmid library of female half-smooth tongue sole, Cynoglossus semilaevis. Three hundred eighty-four clones were randomly selected to sequence (double strand reading), and 168 sequences in 143 clones were found to contain microsatellites. Of the 101 primer pairs designed, 64 gave polymorphic polymerase chain reaction products. Based on characterization with 36 individuals, the number of alleles ranged from two to nine. The values of observed and expected heterozygosities varied from 0.06 to 1.00 and from 0.05 to 0.94, respectively. These markers have the potential as tools for population structure evaluation, ecological analyses and linkage map construction.