Enhancing antibacterial properties of titanium implants through a novel Ag-TiO2-OTS nanocomposite coating: a comprehensive study on resist-killing-disintegrate approach.

Titanium (Ti) implants are widely used in orthopedic and dental applications due to their excellent biocompatibility and mechanical properties. However, bacterial adhesion and subsequent biofilm formation on implant surfaces pose a significant risk of postoperative infections and complications. Conventional surface modifications often lack long-lasting antibacterial efficacy, necessitating the development of novel coatings with enhanced antimicrobial properties. This study aims to develop a novel Ag-TiO2-OTS (Silver-Titanium dioxide-Octadecyltrichlorosilane, ATO) nanocomposite coating, through a chemical plating method. By employing a 'resist-killing-disintegrate' approach, the coating is designed to inhibit bacterial adhesion effectively, and facilitate pollutant removal with lasting effects. Characterization of the coatings was performed using spectroscopy, electron microscopy, and contact angle analysis. Antibacterial efficacy, quantitatively evaluated against E. coli and S. aureus over 168 h, showed a significant reduction in bacterial adhesion by 76.6% and 66.5% respectively, and bacterial removal rates were up to 83.8% and 73.3% in comparison to uncoated Ti-base material. Additionally, antibacterial assays indicated that the ratio of the Lifshitz-van der Waals apolar component to electron donor surface energy components significantly influences bacterial adhesion and removal, underscoring a tunable parameter for optimizing antibacterial surfaces. Biocompatibility assessments with the L929 cell line revealed that the ATO coatings exhibited excellent biocompatibility, with minimal cytotoxicity and no significant impact on cell proliferation or apoptosis. The ATO coatings provided a multi-functionality surface that not only resists bacterial colonization but also possesses self-cleaning capabilities, thereby marking a substantial advancement in the development of antibacterial coatings for medical implants.

Cyanobacterial VOCs ß-ionone and ß-cyclocitral poisoning Lemna turionifera by triggering programmed cell death.

ß-Ionone and ß-cyclocitral are two typical components in cyanobacterial volatiles, which can poison aquatic plants and even cause death. To reveal the toxic mechanisms of the two compounds on aquatic plants through programmed cell death (PCD), the photosynthetic capacities, caspase-3-like activity, DNA fragmentation and ladders, as well as expression of the genes associated with PCD in Lemna turionifera were investigated in exposure to ß-ionone (0.2 mM) and ß-cyclocitral (0.4 mM) at lethal concentration. With prolonging the treatment time, L. turionifera fronds gradually died, and photosynthetic capacities gradually reduced and even disappeared at the 96th h. This demonstrated that the death process might be a PCD rather than a necrosis, due to the gradual loss of physiological activities. When L. turionifera underwent the death, caspase-3-like was activated after 3 h, and reached to the strongest activity at the 24th h. TUNEL-positive nuclei were detected after 12 h, and appeared in large numbers at the 48th h. The DNA was cleaved by Ca2+-dependent endonucleases and showed obviously ladders. In addition, the expression of 5 genes (TSPO, ERN1, CTSB, CYC, and ATR) positively related with PCD initiation was up-regulated, while the expression of 2 genes (RRM2 and TUBA) negatively related with PCD initiation was down-regulated. Therefore, ß-ionone and ß-cyclocitral can poison L. turionifera by adjusting related gene expression to trigger PCD.

Toxic mechanism of two cyanobacterial volatiles ß-cyclocitral and ß-ionone on the photosynthesis in duckweed by altering gene expression.

Volatile organic compounds (VOCs) promote cyanobacteria dominating eutrophicated waters, with aquatic plant decrease and even disappearance. To uncover the toxic mechanism of cyanobacterial VOCs on aquatic plants, we investigated the growth, photosynthetic pigment levels, photosynthetic abilities and related gene expression in duckweed treated with ß-cyclocitral and ß-ionone, 2 main components in the VOCs. The levels of chlorophylls and carotenoids gradually declined with raising the concentration of the 2 compounds and prolonging the treatment time. Their decline should result from the down-regulation of 8 genes associated with photosynthetic pigment biosynthesis and up-regulation of 2 genes involved in carotenoid degradation. The reduction was also found in the photosystem II (PSII) efficiency and O2 evolution rate, which should result from the lowered photosynthetic pigment levels and down-regulation of 38 genes related with photosynthetic process. The frond numbers, total frond area and fresh weight gradually decreased with raising the 2 compound concentration, which may result from the lowered photosynthetic abilities as well as down-regulated expression of 7 genes associated with growth-promoting hormone biosynthesis and signal transduction. It can be speculated that cyanobacterial VOCs may poison aquatic plants by lowering the photosynthesis and growth through altering related gene expression.

A Novel Calix[4]Crown-Based 1,3,4-Oxadiazole as a Fluorescent Chemosensor for Copper(II) Ion Detection.

The synthesis and characterization of a novel florescent chemosensor 1 with two different types of cationic binding sites have been reported in this work, which is a calix[4]crown derivative in 1,3-alternate conformation bearing two 2-phenyl-5-(4-dimethylaminopyenyl)-1,3,4-oxadiazole units. The recognition behaviors of 1 in dichloromethane/acetonitrile solution to alkali metal ions (Na+ and K+), alkaline earth metal ions (Mg2+ and Ca2+), and transition metal ions (Co2+, Ni2+, Zn2+, Cd2+, Cu2+, Mn2+, and Ag+) have been investigated by UV-Vis and fluorescence spectra. The fluorescence of 1 might be quenched selectively by Cu2+ due to the photo-induced electron transfer mechanism, and the quenched emission from 1 could be partly revived by the addition of Ca2+ or Mg2+; thus, the receptor 1 might be worked as an on-off switchable fluorescent chemosensor triggered by metal ion exchange.

The Relationship between Post-Traumatic Symptoms, Parenting Style, and Resilience among Adolescents in Liaoning, China: A Cross-Sectional Study.

BACKGROUND: In China, a growing number of adolescents have experienced traumatic events that have resulted in PTSD (post-traumatic stress disorder). Post-traumatic symptoms are common psychological problems in adolescents who have experienced traumatic events. However, existing studies tend to focus on the factors influencing PTSD, such as the response styles and social support, and studies on the relationships between parenting style, resilience and post-traumatic symptoms are still rare. OBJECTIVES: To analyze the relationships between parenting style, resilience and post-traumatic symptoms among adolescents in China. METHODS: A cross-sectional survey was conducted from June to December 2013 in the Liaoning Province, China. N = 5765 adolescents (aged 12 to 18 years old) were ultimately chosen to participate. The Chinese version of the Essen Trauma Inventory for Kids and Juveniles (ETI-KJ), a modified version of the Parental Authority Questionnaire, and the Chinese Resilience Scale were used to estimate the post-traumatic symptoms, parenting style, and resilience, respectively. Pearson's correlations, multiple linear regression analyses and structural equation modeling (SEM) were applied to analyze the data. RESULTS: Of the adolescents, 39.76% (N = 2292) had been exposed to traumatic events during their lives. The prevalence of probable PTSD at the time of the interview (one-month-prevalence) was 12.65%. Parenting style and resilience were significantly associated with post-traumatic symptoms. According to the SEM, parenting style had a significant direct effect on resilience (0.70, P<0.01) and post-traumatic symptoms (-0.15, P<0.05), and resilience had a significant direct effect on the post-traumatic symptoms (-0.43, P<0.01). Furthermore, parenting style had a significant indirect effect (-0.43×0.70 = -0.30. P<0.01) on the post-traumatic symptoms through resilience. The SEM significantly explained 49% of the variance in resilience and 30% of the variance in post-traumatic symptoms. CONCLUSIONS: Parenting style and resilience have significant effects on adolescents' post-traumatic symptoms. Schools and social-related departments could share knowledge on the impact of parenting style with parents enabling them to improve their own parenting style and their children's resilience and ability to respond effectively to traumatic events.

Quantitative assessment of binding affinities for nanoparticles targeted to vulnerable plaque.

Recent successes in targeted immune and cell-based therapies have driven new directions for pharmaceutical research. With the rise of these new therapies there is an unfilled need for companion diagnostics to assess patients' potential for therapeutic response. Targeted nanomaterials have been widely investigated to fill this niche; however, in contrast to small molecule or peptide-based targeted agents, binding affinities are not reported for nanomaterials, and to date there has been no standard, quantitative measure for the interaction of targeted nanoparticle agents with their targets. Without a standard measure, accurate comparisons between systems and optimization of targeting behavior are challenging. Here, we demonstrate a method for quantitative assessment of the binding affinity for targeted nanoparticles to cell surface receptors in living systems and apply it to optimize the development of a novel targeted nanoprobe for imaging vulnerable atherosclerotic plaques. In this work, we developed sulfated dextran-coated iron oxide nanoparticles with specific targeting to macrophages, a cell type whose density strongly correlates with plaque vulnerability. Detailed quantitative, in vitro characterizations of (111)In(3+) radiolabeled probes show high-affinity binding to the macrophage scavenger receptor A (SR-A). Cell uptake studies illustrate that higher surface sulfation levels result in much higher uptake efficiency by macrophages. We use a modified Scatchard analysis to quantitatively describe nanoparticle binding to targeted receptors. This characterization represents a potential new standard metric for targeted nanomaterials.