Ligand-Bound CO2 as a Nonclassical Route toward Efficient Photocatalytic CO2 Reduction with a Ni N-Confused Porphyrin.

Implementing the synergistic effects between the metal and the ligand has successfully streamlined the energetics for CO2 activation and gained high catalytic activities, establishing the important breakthroughs in photocatalytic CO2 reduction. Herein, we describe a Ni(II) N-confused porphyrin complex (NiNCP) featuring an acidic N-H group. It is readily deprotonated and exists in an anion form during catalysis. Owing to this functional site, NiNCP gave rise to an outstanding turnover number (TON) as high as 217,000 with a 98% selectivity for CO2 reduction to CO, while the parent Ni(II) porphyrin (NiTPP) was found to be nearly inactive. Our mechanistic analysis revealed a nonclassical reaction pattern where CO2 was effectively activated via the attack of the Lewis-basic ligand. The resulting ligand-bound CO2 adduct could be further reduced to produce CO. This new metal-ligand synergistic effect is anticipated to inspire the design of highly active catalysts for small molecule activations.

Accelerating Charge Kinetics in Photocatalytic CO2 Reduction by Modulating the Cobalt Coordination in Heterostructures of Cadmium Sulfide/Metal-Organic Layer.

Artificial photocatalytic CO2 reduction (CO2 R) holds great promise to directly store solar energy into chemical bonds. The slow charge and mass transfer kinetics at the triphasic solid-liquid-gas interface calls for the rational design of heterogeneous photocatalysts concertedly boosting interfacial charge transfer, local CO2 concentration, and exposure of active sites. To meet these requirements, in this study heterostructures of CdS/MOL (MOL = metal-organic layer) furnishing different redox Co sites are fabricated for CO2 R photocatalysts. It is found that the coordination environment of Co is key to photocatalytic activity. The best catalyst ensemble comprising ligand-chelated Co2+ with the bipyridine electron mediator demonstrates a high CO yield rate of 1523 µmol h-1 gcat -1 , selectivity of 95.8% and TON of 1462.4, which are ranked among the best seen in literature. Comprehensive photochemical and electroanalytical characterizations attribute the high CO2 R performance to the improved photocarrier separation and charge kinetics originated from the proper energy band alignment and coordination chemistry. This work highlights the construction of 2D heterostructures and modulation of transition metal coordination to expedite the charge kinetics in photocatalytic CO2 reduction.

Rapid, Selective, and Chemical-Free Removal of Dissolved Silica from Water via Electrosorption: Feasibility and Mechanisms.

The unavoidable and detrimental formation of silica scale in engineered processes necessitates the urgent development of effective, economic, and sustainable strategies for dissolved silica removal from water. Herein, we demonstrate a rapid, chemical-free, and selective silica removal method using electrosorption. Specifically, we confirm the feasibility of exploiting local pH dynamics at the electrodes in flow-through electrosorption, achieved through a counterintuitive cell configuration design, to induce ionization and concomitant electrosorption of dissolved silica. In addition, to improve the feasibility of silica electrosorption under high-salinity solutions, we developed a silica-selective anode by functionalizing porous activated carbon cloths with aluminum hydroxide nanoparticles (Al(OH)3-p-ACC). The modification markedly enhances silica sorption capacity (2.8 vs 1.1 mgsilica ganode-1) and reduces the specific energy consumption (13.3 vs 19.8 kWh kgsilica-1). Notably, the modified electrode retains remarkable silica sorption capacity even in the presence of high concentrations of co-occurring ions (up to 100 mM NaCl). The mechanisms underlying the superior silica removal stability and selectivity with the Al(OH)3-p-ACC electrode are also elucidated, revealing a synergistic interaction involving outer-sphere and inner-sphere complexation between dissolved silica and Al(OH)3 nanoparticles on the electrodes. Moreover, we find that effective regeneration of the electrodes may be achieved by applying a reverse potential during discharge, although complete regeneration of the modified electrodes may necessitate alternative materials or process optimization. We recommend the adoption of feedwater-specific designs for the development of future silica-selective electrodes in electrosorption capable of meeting silica removal demands across a wide range of engineered systems.

Comparative genomics analysis provide insights into evolution and stress responses of Lhcb genes in Rosaceae fruit crops.

BACKGROUND: Light-harvesting chlorophyll a/b b evelopment of higher plants and in response to abiotic stress. Previous works has demonstrated that that Lhcb genes were involved in the phytochrome regulation and responded to the different light and temperature conditions in Poaceae (such as maize). However, the evolution and functions of Lhcb genes remains poorly characterized in important Rosaceae species. RESULTS: In this investigation, we conducted a genome-wide analysis and identified a total of 212 Lhcb genes across nine Rosaceae species. Specifically, we found 23 Lhcb genes in Fragaria vesca, 20 in Prunus armeniaca, 33 in Malus domestica 'Gala', 21 in Prunus persica, 33 in Rosa chinensis, 29 in Pyrus bretschneideri, 18 in Rubus occidentalis, 20 in Prunus mume, and 15 in Prunus salicina. Phylogenetic analysis revealed that the Lhcb gene family could be classified into seven major subfamilies, with members of each subfamily sharing similar conserved motifs. And, the functions of each subfamily was predicted based on the previous reports from other species. The Lhcb proteins were highly conserved within their respective subfamilies, suggesting similar functions. Interestingly, we observed similar peaks in Ks values (0.1-0.2) for Lhcb genes in apple and pear, indicating a recent whole genome duplication event (about 30 to 45 million years ago). Additionally, a few Lhcb genes underwent tandem duplication and were located across all chromosomes of nine species of Rosaceae. Furthermore, the analysis of the cis-acting elements in the 2000 bp promoter region upstream of the pear Lhcb gene revealed four main categories: light response correlation, stress response correlation, hormone response correlation, and plant growth. Quantitative expression analysis demonstrated that Lhcb genes exhibited tissue-specific expression patterns and responded differently to low-temperature stress in Rosaceae species. CONCLUSIONS: These findings shed light on the evolution and phylogeny of Lhcb genes in Rosaceae and highlight the critical role of Lhcb in pear's response to low temperatures. The results obtained provide valuable insights for further investigations into the functions of Lhcb genes in Rosaceae, and these functional genes will be used for further fruit tree breeding and improvement to cope with the current climate changes.

Genetic evidence strengthens the bidirectional connection between gut microbiota and periodontitis: insights from a two-sample Mendelian randomization study.

BACKGROUND: Recent research has established the correlation between gut microbiota and periodontitis via oral-gut axis. Intestinal dysbiosis may play a pivotal bridging role in extra-oral inflammatory comorbidities caused by periodontitis. However, it is unclear whether the link is merely correlative or orchestrated by causative mechanistic interactions. This two-sample Mendelian randomization (MR) study was performed to evaluate the potential bidirectional causal relationships between gut microbiota and periodontitis. MATERIALS AND METHODS: A two-sample MR analysis was performed using summary statistics from genome-wide association studies (GWAS) for gut microbiota (n = 18,340) and periodontitis (cases = 12,251; controls = 22,845). The inverse-variance weighted (IVW) method was used for the primary analysis, and we employed sensitivity analyses to assess the robustness of the main results. The PhenoScanner database was then searched for pleiotropy SNPs associated with potential confounders. In order to identify the possibly influential SNPs, we further conducted the leave-one-out analysis. Finally, a reverse MR analysis was performed to evaluate the possibility of links between periodontitis and genetically predicted gut microbiota alternation. RESULTS: 2,699 single nucleotide polymorphisms (SNPs) associated with 196 microbiota genera were selected as instrumental variables (IVs). IVW method suggested that order Enterobacteriales (OR: 1.35, 95% CI 1.10-1.66), family Bacteroidales S24.7group (OR: 1.22, 95% CI 1.05-1.41), genus Lachnospiraceae UCG008 (OR: 1.16, 95% CI 1.03-1.31), genus Prevotella 7 (OR: 1.11, 95% CI 1.01-1.23), and order Pasteurellales (OR: 1.12, 95% CI 1.00-1.26) may be associated with a higher risk of periodontitis, while genus Ruminiclostridium 6 may be linked to a lower risk (OR: 0.82, 95% CI 0.70-0.95). The sensitivity and heterogeneity analyses yielded no indication of horizontal pleiotropy or heterogeneity. Only the association between order Enterobacteriales and the likelihood of periodontitis remained consistent across all alternative MR approaches. In the reverse MR analysis, four microbiota genera were genetically predicted to be down-regulated in periodontitis, whereas two were predicted to be up-regulated. CONCLUSIONS: The present MR analysis demonstrated the potential bidirectional causal relationships between gut microbiota and periodontitis. Our research provided fresh insights for the prevention and management of periodontitis. Future research is required to support the finding of our current study.

Electrosorption Integrated with Bipolar Membrane Water Dissociation: A Coupled Approach to Chemical-free Boron Removal.

Boron removal from aqueous solutions has long persisted as a technological challenge, accounting for a disproportionately large fraction of the chemical and energy usage in seawater desalination and other industrial processes like lithium recovery. Here, we introduce a novel electrosorption-based boron removal technology with the capability to overcome the limitations of current state-of-the-art methods. Specifically, we incorporate a bipolar membrane (BPM) between a pair of porous carbon electrodes, demonstrating a synergized BPM-electrosorption process for the first time. The ion transport and charge transfer mechanisms of the BPM-electrosorption system are thoroughly investigated, confirming that water dissociation in the BPM is highly coupled with electrosorption of anions at the anode. We then demonstrate effective boron removal by the BPM-electrosorption system and verify that the mechanism for boron removal is electrosorption, as opposed to adsorption on the carbon electrodes or in the BPM. The effect of applied voltage on the boron removal performance is then evaluated, revealing that applied potentials above ∼1.0 V result in a decline in process efficiency due to the increased prevalence of detrimental Faradaic reactions at the anode. The BPM-electrosorption system is then directly compared with flow-through electrosorption, highlighting key advantages of the process with regard to boron sorption capacity and energy consumption. Overall, the BPM-electrosorption shows promising boron removal capability, with a sorption capacity >4.5 µmol g-C-1 and a corresponding specific energy consumption of <2.5 kWh g-B-1.

Impact of COVID-19 on patient follow-up during supportive periodontal therapy: a retrospective study based on phone call survey.

BACKGROUND: COVID-19 and the subsequent intermittent lockdown measures from 2020 to 2022 in China critically disrupted regular medical activities, including dental care. This study aimed to investigate the impact of COVID-19 on long-term follow-up at the Stomatology Hospital, Zhejiang University School of Medicine and to evaluate potential causes of loss to follow-up. METHODS: A total of 1062 patients with periodontitis who visited the hospital from January 2019 to June 2022 were included in this study, and patient information was collected retrospectively in the form of a telephone questionnaire. The questionnaire consisted of 19 questions in four areas: demographic characteristics, clinical periodontal parameters, oral hygiene habits, and follow-up-related open-ended questions (specific reasons for loss to follow-up, attitudes toward follow-up and suggestions for increasing participation in future follow-ups). Regression analysis of factors influencing the follow-up of patients with periodontitis were analyzed by regression analysis using R (v4.2.3) software. RESULTS: A total of 536 (50.47%) valid questionnaires were collected from 1062 patients. Personal factors (42.5%), instead of the COVID-19 epidemic (20.0%), were the main factors that impacted the loss to follow-up in long-term periodontal treatment, while work factors (19.8%), hospital factors (16.4%), and transportation or distance factors (14.7%) were all important factors. A family history of periodontitis [odds ratio (OR) = 0.567, 95% confidence interval (CI): 0.393, 0.817, p = 0.002], as well as frequent use of dental devices (OR = 0.540, 95% CI: 0.375, 0.777, p = 0.001), were significantly associated with a "negative" attitude toward follow-up visits. CONCLUSION: This survey suggests that the COVID-19 epidemic factor was an important cause contributed to the loss to follow-up during supportive periodontal therapy (SPT) among a variety of potential factors. Majority of patients had negative attitudes toward subsequent continued participation in supportive care.

Covalently Grafting Graphene onto Si Photocathode to Expedite Aqueous Photoelectrochemical CO2 Reduction.

Silicon semiconductor functionalized with molecular catalysts emerges as a promising cathode for photoelectrochemical (PEC) CO2 reduction reaction (CO2 RR). However, the limited kinetics and stabilities remains a major hurdle for the development of such composites. We herein report an assembling strategy of silicon photocathodes via chemically grafting a conductive graphene layer onto the surface of n+ -p Si followed by catalyst immobilization. The covalently-linked graphene layer effectively enhances the photogenerated carriers transfer between the cathode and the reduction catalyst, and improves the operating stability of the electrode. Strikingly, we demonstrate that altering the stacking configuration of the immobilized cobalt tetraphenylporphyrin (CoTPP) catalyst through calcination can further enhance the electron transfer rate and the PEC performance. At the end, the graphene-coated Si cathode immobilized with CoTPP catalyst managed to sustain a stable 1-Sun photocurrent of -1.65 mA cm-2 over 16 h for CO production in water at a near neutral potential of -0.1 V vs. reversible hydrogen electrode. This represents a remarkable improvement of PEC CO2 RR performance in contrast to the reported photocathodes functionalized with molecular catalysts.

Proton Shuttling by Polyaniline of High Brønsted Basicity for Improved Electrocatalytic Ethylene Production from CO2.

Hybrid organic/inorganic composites with the organic phase tailored to modulate local chemical environment at the Cu surface arise as an enchanting category of catalysts for electrocatalytic CO2 reduction reaction (CO2 RR). A fundamental understanding on how the organics of different functionality, polarity, and hydrophobicity affect the reaction path is, however, still lacking to guide rational catalyst design. Herein, polypyrrole (PPy) and polyaniline (PANI) manifesting different Brønsted basicity are compared for their regulatory roles on the CO2 RR pathways regarding *CO coverage, proton source and interfacial polarity. Concerted efforts from in situ IR, Raman and operando modelling unveil that at the PPy/Cu interface with limited *CO coverage, hydridic *H produced by the Volmer step favors the carbon hydrogenation of *CO to form *CHO through a Tafel process; Whereas at the PANI/Cu interface with concentrated CO2 and high *CO coverage, protonic H+ shuttled through the benzenoid -NH- protonates the oxygen of *CO, yielding *COH for asymmetric coupling with nearby *CO to form *OCCOH under favored energetics. As a result of the tailored chemical environment, the restructured PANI/Cu composite demonstrates a high partial current density of 0.41 A cm-2 at a maximal Faraday efficiency of 67.5 % for ethylene production, ranking among states of the art.

Redox-Driven Recrystallization of PbO2.

Lead(IV) oxide (PbO2) is one of the lead corrosion products that forms on the inner surface of lead pipes used for drinking water supply. It can maintain low dissolved Pb(II) concentrations when free chlorine is present. When free chlorine is depleted, PbO2 and soluble Pb(II) will co-occur in these systems. This study used a stable lead isotope (207Pb) as a tracer to examine the interaction between aqueous Pb(II) and solid PbO2 at conditions with no net change in dissolved Pb concentration. While the dissolved Pb(II) concentration remained unchanged, significant isotope exchange occurred that indicated that substantial amounts (24.3-35.0% based on the homogeneous recrystallization model) of the Pb atoms in the PbO2 solids had been exchanged with those in solution over 264 h. Neither α-PbO2 nor ß-PbO2 displayed a change in mineralogy, particle size, or oxidation state after reaction with aqueous Pb(II). The combined isotope exchange and solid characterization results indicate that redox-driven recrystallization of PbO2 had occurred. Such redox-driven recrystallization is likely to occur in water that stagnates in lead pipes that contain PbO2, and this recrystallization may alter the reactivity of PbO2 with respect to its stability and susceptibility to reductive dissolution.

Exchange of Adsorbed Pb(II) at the Rutile Surface: Rates and Mechanisms.

The dynamics of Pb(II) at mineral surfaces affect its mobility in the environment. Pb(II) forms inner- and outer-sphere complexes on mineral surfaces, and this adsorbed pool often represents a large portion of the bioaccessible Pb in contaminated soils. To assess the lability of this potentially reactive adsorbed Pb(II) pool at metal oxide surfaces, we performed Pb(II) isotope exchange measurements between dissolved Pb(II) enriched in 207Pb and natural isotopic abundance Pb(II) adsorbed to rutile at pH 5, 6, and 7. We find that ∼95% of the adsorbed lead is exchangeable. An initially fast exchange (<1 h) is followed by a slower exchange that occurs on a time scale of hours to days. Pb LIII-edge extended X-ray absorption fine structure spectra indicate that similar binding mechanisms are present at all pH values and Pb(II) loadings, implying that differences in exchange rates across the pH range examined are not attributable to changes in the coordination environment. The slower exchange at pH 5 may be associated with interparticle and intraparticle diffusion resulting from particle aggregation. These findings demonstrate that the dissolved Pb(II) pool can be rapidly replenished by adsorbed Pb(II) if this pool is drawn down incrementally by biological uptake or a shift in chemical conditions.

Effects of Cu(II) and Zn(II) on PbO2 Reductive Dissolution under Drinking Water Conditions: Short-term Inhibition and Long-term Enhancement.

Lead oxide (PbO2) has the lowest solubility with free chlorine among Pb corrosion products, but depletion of free chlorine or a switch from free chlorine to monochloramine can cause its reductive dissolution. We previously reported that Cu(II) and Zn(II) inhibited PbO2 reductive dissolution within 12 h. Here, we expanded on this work by performing longer duration experiments and further exploring the underlying mechanisms. Between 12 and 48 h, Cu(II) and Zn(II) had no discernible effect on PbO2 reductive dissolution. From 48 to 192 h, Cu(II) and Zn(II) enhanced PbO2 reductive dissolution. Dissolved oxygen (DO) concentrations followed the same trends as PbO2 reductive dissolution, indicating that the DO was produced by PbO2 reductive dissolution. On the basis of extended X-ray absorption fine structure spectra, we hypothesize that the inhibitory effect of Cu(II) and Zn(II) on PbO2 reductive dissolution (<12 h) is caused by decreasing abundance of protonated sites on the PbO2 surface. The enhanced dissolution (>48 h) may be caused by competitive adsorption of Cu(II) and Zn(II) with Pb(II), which could limit the adsorption of Pb(II) onto PbO2 that could otherwise inhibit reductive dissolution. This study indicates that stagnation time plays a vital role in determining cations' effects on the stability of Pb corrosion products.

MicroRNA-32-5p attenuates cerebral ischemia/reperfusion injuries by modulating the phosphatase and tensin homologous protein.

Non-coding RNAs have recently attracted much attention with the potential in the treatment of cerebral ischemia/reperfusion (I/R) injuries. In this study, we investigated the role of miR-32-5p in cerebral I/R injuries by using oxygen-glucose deprivation/reperfusion (OGD/R) PC12 cells and middle cerebral artery occlusion/reperfusion (MCAO/R) rats. The expression of genes and proteins were detected by RT-qPCR and Western blot, respectively. The function of OGD/R PC12 cells was detected using MTT assay and flow cytometry analysis. The influences of MCAO/R on rats was evaluated by measuring the infarct volume and brain water content. Bioinformatics analysis and luciferase gene reporter assay were used to identify the relationship between miR-32-5p and PTEN. The results showed that miR-32-5p had neuroprotective effects on OGD/R induced PC12 cells and MCAO/R injured rats' brain. The level of miR-32-5p was significantly reduced after OGD/R. Overexpression of miR-32-5p significantly reduced MCAO/R-induced brain damages in rats. Moreover, PTEN was found to be a target of miR-32-5p, and overexpression of PTEN attenuated the effects of miR-32-5p overexpression on cerebral I/R injuries. In addition, miR-32-5p was able to activate PI3K/AKT signaling by inhibiting PTEN. In conclusion, miR-32-5p prevents brain I/R injuries through modulating PTEN/PI3K/AKT signaling pathway.

Effect of Rhythm of Music Therapy on Gait in Patients with Stroke.

AIM: This study aims to analyze the effects of rhythm of music therapy on gait in patients with ischemic stroke, and explore the value of music therapy in walking training in stroke. METHODS: The present study is a prospective clinical study. Sixty patients with ischemic stroke, who were admitted to our hospital from October 2017 to December 2018, were enrolled. These patients were divided into two groups, according to the method of the random number table, with thirty patients in each group: control group and study group. Patients in the control group received conventional drug therapy, rehabilitation training and walking training, while the patients in the study group were given music therapy on the basis of the above mentioned therapies for four weeks, during which Sunday was regarded as a rest day, and the music therapy was suspended. The main outcome measures included indexes in evaluating the walking ability of patients in these two groups. At each time point, the Fugl-Meyer Assessment (FMA), Berg Balance Scale (BBS) and stroke rehabilitation treatment satisfaction questionnaire were used. RESULTS: The results revealed that the stride length, cadence and maximum velocity were higher in patients in the study group, when compared to patients in the control group, at the second week and end of the therapy, and the difference in step length between the affected side and healthy side was significantly lower in the study group than in the control group. These differences were statistically significant (P < 0.05). In the second week of therapy and at the end of therapy, the FMA and BBS scores were higher in the study group than in the control group, and the difference was statistically significant (P < 0.05). The total satisfaction rate was higher in the study group than in the control group, and the difference was statistically significant (P < 0.05). CONCLUSION: Under the stimulation of music rhythm, applying music therapy to patients with ischemic stroke can improve their gait, walking ability, lower limb motor function, balance ability and treatment satisfaction.

Best-first search guided multistage mass spectrometry-based glycan identification.

MOTIVATION: Glycan identification has long been hampered by complicated branching patterns and various isomeric structures of glycans. Multistage mass spectrometry (MSn) is a promising glycan identification technique as it generates multiple-level fragments of a glycan, which can be explored to deduce branching pattern of the glycan and further distinguish it from other candidates with identical mass. However, the automatic glycan identification still remains a challenge since it mainly relies on expertise to guide a MSn instrument to generate spectra. RESULTS: Here, we proposed a novel method, named bestFSA, based on a best-first search algorithm to guide the process of spectrum producing in glycan identification using MSn. BestFSA is able to select the most appropriate peaks for next round of experiments and complete the identification using as few experimental rounds. Our analysis of seven representative glycans shows that bestFSA correctly distinguishes actual glycans efficiently and suggested bestFSA could be used in practical glycan identification. The combination of the MSn technology coupled with bestFSA should greatly facilitate the automatic identification of glycan branching patterns, with significantly improved identification sensitivity, and reduce time and cost of MSn experiments. AVAILABILITY AND IMPLEMENTATION: http://glycan.ict.ac.cn. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Effect of Cu(II) on Mn(II) Oxidation by Free Chlorine To Form Mn Oxides at Drinking Water Conditions.

The chemical oxidation of dissolved Mn(II) to Mn(III/IV) oxides (MnOx) can lead to the accumulation of Mn deposits in drinking water distribution systems. However, Mn(II) oxidation by free chlorine is quite slow under mild conditions (e.g., pH 7.7 and 1.0 mg/L Cl2). This study found a significant role for Cu(II) in Mn(II) oxidation under conditions relevant to the supply of chlorinated drinking water. At pH 7.7, dissolved Cu(II) accelerated Mn(II) oxidation more than 10 times with a dose of 20 µg/L. Solid characterization revealed that during Mn(II) oxidation, Cu(II) adsorbed to freshly formed MnOx and produced Mn-Cu mixtures (denoted as MnOx-Cu(II)). An autocatalytic model for the reaction kinetics suggested that the freshly formed MnOx-Cu(II) had a much higher catalytic activity than that of pure MnOx. Solid CuO also catalyzed Mn(II) oxidation, and kinetic modeling indicated that after an initial oxidation of Mn(II) facilitated by the CuO surface, the freshly formed MnOx-Cu(II) on CuO surface played the dominant role in accelerating further Mn(II) oxidation. This study indicates a high potential for the formation of Mn oxides at locations in a drinking water distribution system or in premise plumbing where both Mn(II) and Cu(II) are available. It provides insights into the co-occurrence of other metals with Mn deposits that is frequently observed in distribution systems.

Role of Manganese in Accelerating the Oxidation of Pb(II) Carbonate Solids to Pb(IV) Oxide at Drinking Water Conditions.

Pb(II) carbonate solids are corrosion products that form on the inner surfaces of lead service lines (LSLs) and can be oxidized by free chlorine to form Pb(IV) oxide (PbO2). The formation of PbO2 can maintain low dissolved lead concentrations in drinking water, but PbO2 can dissolve if a free chlorine residual is not maintained. Experiments demonstrated that the oxidation of Pb(II) carbonate by free chlorine was faster with manganese (Mn). Without Mn(II), the oxidation of Pb(II) carbonate was an autocatalytic process. With Mn(II), the overall oxidation rate was 2 orders of magnitude faster than without Mn(II). X-ray diffraction and free chlorine consumption profiles indicated that δ-MnO2 was formed within several minutes of the reaction of Mn(II) with free chlorine, and δ-MnO2 catalyzed the oxidation of Pb(II) carbonate by free chlorine. Free chlorine consumption profiles for Pb(II) carbonate with and without Mn(II) were interpreted based on the kinetics and stoichiometry of the underlying chemical reactions. These findings highlight the importance of Mn in accelerating the formation of PbO2 in water with Pb(II) carbonate solids and free chlorine, and it may help explain why PbO2 is observed on LSLs of some but not all water systems that use free chlorine.

Traumatic occlusion aggravates bone loss during periodontitis and activates Hippo-YAP pathway.

AIM: This study aimed at exploring changes in YAP expression and their effect on periodontitis (PD) combined with traumatic occlusion (TO). MATERIALS AND METHODS: BALB/cJ mice were used to establish a PD model by local administration of Porphyromonas gingivalis (P.g, ATCC 33277) and a TO model by occlusal elevation (OE) using composite resin bonding on the bilateral maxillary molar. The mouse fibroblast cell line (L929) and pre-osteoblast cell line (MC3T3-E1) were subjected to cyclic tensile/compressive stress and inflammatory stimuli (lipopolysaccharide from Escherichia coli) to verify in vivo results. RESULTS: Severe bone resorption was observed by microCT scanning in OE with P.g group, when compared to OE only and P.g only groups. Mechanical stress caused by OE activated the Hippo-YAP pathway in periodontal tissues and upregulated the expression of JNK/AP-1. OE with P.g further promoted the expression of YAP and JNK/AP1, leading to the upregulation of the JNK/AP-1 related inflammatory cytokines TNF-α and IL6. Similar results were obtained when osteoblasts were subjected to mechanical stress in vitro. CONCLUSIONS: Our study demonstrated that periodontitis with TO caused severe inflammation-induced bone resorption. Activation of YAP and upregulation of JNK/AP-1 induced by TO potentially aggravated the symptoms of PD.

Inhibition of Ctsk alleviates periodontitis and comorbid rheumatoid arthritis via downregulation of the TLR9 signalling pathway.

AIM: In this study, we investigate the mechanistic link between rheumatoid arthritis (RA) and periodontitis to identify a novel target (cathepsin K; Ctsk) for the treatment of comorbid periodontitis and RA. METHODS: An experimental model of periodontitis with arthritis was established in DBA/1 mice. We then tested the effect of BML-244, a specific inhibitor of Ctsk, by quantifying several inflammatory markers of TLR9 signalling both in vivo and in vitro. RESULTS: Our results showed that periodontitis-rheumatoid arthritis comorbidity causes severer periodontal bone and joint cartilage destruction than either disease alone. Inhibition of Ctsk reduced infiltration by dendritic cells and T cells and inflammatory cytokine production; these improvements alleviated the hard-tissue erosion in periodontitis and RA as measured by bone erosion in periodontal lesions and cartilage destruction in knee joints. Inhibition of Ctsk also decreased the expression of TLR4 and TLR9 in vivo, whereas in vitro experiments indicated that Ctsk is involved specifically in the production of cytokines in response to TLR9 engagement. CONCLUSION: Our data reveal that periodontitis and RA may have additive pathological effects through dysregulation of the TLR9 pathway and that Ctsk is a critical mediator of this pathway and contributes to the pathogenesis of RA and periodontitis.