Click Chemistry in Lithium-Metal Batteries.

Lithium-metal batteries (LMBs) are considered the "holy grail" of the next-generation energy storage systems, and solid-state electrolytes (SSEs) are a kind of critical component assembled in LMBs. However, as one of the most important branches of SSEs, polymer-based electrolytes (PEs) possess several native drawbacks including insufficient ionic conductivity and so on. Click chemistry is a simple, efficient, regioselective, and stereoselective synthesis method, which can be used not only for preparing PEs with outstanding physical and chemical performances, but also for optimizing the stability of solid electrolyte interphase (SEI) layer and elevate the cycling properties of LMBs effectively. Here it is primarily focused on evaluating the merits of click chemistry, summarizing its existing challenges and outlining its increasing role for the designing and fabrication of advanced PEs. The fundamental requirements for reconstructing artificial SEI layer through click chemistry are also summarized, with the aim to offer a thorough comprehension and provide a strategic guidance for exploring the potentials of click chemistry in the field of LMBs.

Visible-Light-Driven α-Substituted Amines Enabled by In Situ Formation of Amine Substrate Aggregates.

A visible-light-driven, photocatalyst-free, air-promoted, α-substituted reaction of amines with varying nucleophiles is described. The amine substrate aggregates formed in situ through physical π-π stacking by H2O regulation in organic solvent can absorb visible light and then generate iminium ion intermediates, which undergo nucleophilic substitution reactions with varying nucleophiles to afford α-substituted amines. This reaction features catalyst-free, good functional group tolerance, simple operation procedure, and green reaction conditions.

Road traffic death coding quality in the WHO Mortality Database.

Objective: To evaluate the precision and dependability of road traffic mortality data recorded in the World Health Organization Mortality Database and investigate how uncorrected data influence vital mortality statistics used in traffic safety programmes worldwide. Methods: We assessed country and territory-specific data quality from 2015 to 2020 by calculating the proportions of five types of nonspecific cause of death codes related to road traffic mortality. We compared age-adjusted road traffic mortality and changes in the average annual mortality rate before and after correcting the deaths with nonspecific codes. We generated road traffic mortality projections with both corrected and uncorrected codes, and redistributed the data using the proportionate method. Findings: We analysed data from 124 countries and territories with at least one year of mortality data from 2015 to 2020. The number of countries and territories reporting more than 20% of deaths with ill-defined or unknown cause was 2; countries reporting injury deaths with undetermined intent was 3; countries reporting unspecified unintentional injury deaths was 21; countries reporting unspecified transport crash deaths was 3; and countries reporting unspecified unintentional road traffic deaths was 30. After redistributing deaths with nonspecific codes, road traffic mortality changed by greater than 50% in 7% (5/73) to 18% (9/51) of countries and territories. Conclusion: Nonspecific codes led to inaccurate mortality estimates in many countries. We recommend that injury researchers and policy-makers acknowledge the potential pitfalls of relying on raw or uncorrected road traffic mortality data and instead use corrected data to ensure more accurate estimates when improving road traffic safety programmes.

Evaluating the effectiveness of the safety experience room, an affordable interactive education intervention to prevent unintentional injury among rural preschoolers in China: protocol for a cluster randomized controlled trial.

BACKGROUND: Interactive and experiential learning programs have proven effective to teach children safety and prevent child unintentional injury. However, previously-published programs were designed primarily to address safety concerns of children living in urban, well-resourced areas, and therefore might be less effective or economically infeasible to distribute to children in resource-limited areas, such as those living in rural areas or underdeveloped regions. This proposed study will evaluate the effectiveness of teaching children safety lessons to rural preschoolers in China through the preschool-based Safety Experience Room intervention that was developed based on relevant theories, the lessons of previous intervention research, the characteristics of child injuries in underdeveloped rural areas, and the needs and circumstances of rural families and preschools in China. The study will also evaluate the cost-effectiveness of delivering the program. METHODS AND ANALYSIS: A single-blinded, 12-month follow-up, parallel-group cluster randomized controlled trial with a 1:1 allocation ratio will be implemented in two selected counties. In total, at least 2378 rural preschoolers aged 3-6 years old will be recruited from 12 preschools, 6 in Yang County and 6 in Shicheng County. Clusters will be randomized at the preschool level and allocated to the control group (routine school-based education) or the intervention group (routine school-based education plus the Safety Experience Room education). External support strategies will be implemented by local partners to minimize attrition. Data collection will be conducted at baseline and then every 3 months during a 12-month follow-up time period. Intention-to-treat (ITT) data analysis will be used. Generalized estimation equations (GEE) will evaluate the effectiveness of the program and generalized cost-effectiveness analysis (GCEA) will evaluate the cost-effectiveness of it. A per-protocol (PP) sensitivity analysis will assess the robustness of ITT results. Subgroup analyses will be performed to evaluate the impact of socio-demographic factors on the intervention effect, following the same strategies as the primary analyses. DISCUSSION: The newly-designed Safety Experience Room program is expected to be feasible, effective, and financially beneficial. If these hypotheses prove true, we will take steps to disseminate the program to rural preschools across China. TRIAL REGISTRATION: Chinese Clinical Trial Registry ( http://www.chictr.org.cn ), CHiCTR2000038025, registered on 8 September 2020.

An Ultrasound-Induced Self-Clearance Hydrogel for Male Reversible Contraception.

Nearly half of pregnancies worldwide are unintended mainly due to failure of contraception, resulting in negative effects on women's health. Male contraception techniques, primarily condoms and vasectomy, play a crucial role in birth control, but cannot be both highly effective and reversible at the same time. Herein, an ultrasound (US)-induced self-clearance hydrogel capable of real-time monitoring is utilized for in situ injection into the vas deferens, enabling effective contraception and noninvasive recanalization whenever needed. The hydrogel is composed of (i) sodium alginate (SA) conjugated with reactive oxygen species (ROS)-cleavable thioketal (SA-tK), (ii) titanium dioxide (TiO2), which can generate a specific level of ROS after US treatment, and (iii) calcium chloride (CaCl2), which triggers the formation of the hydrogel. For contraception, the above mixture agents are one-time injected into the vas deferens, which can transform from liquid to hydrogel within 160 s, thereby significantly physically blocking the vas deferens and inhibiting movability of sperm. When fertility is needed, a noninvasive remedial ultrasound can make TiO2 generate ROS, which cleaves SA-tK to destroy the network of the hydrogel. Owing to the recanalization, the refertility rate is restored to 100%. Meanwhile, diagnostic ultrasound (D-US, 22 MHz) can monitor the occlusion and recanalization process in real-time. In summary, the proposed hydrogel contraception can be a reliable, safe, and reversible male contraceptive strategy that addresses an unmet need for men to control their fertility.

Coding quality of deaths and its impact on elderly unintentional fall mortality data from 1990 to 2019: a retrospective analysis of the WHO Mortality Database.

BACKGROUND: Several studies have assessed the reporting quality of all-cause mortality data from the WHO Mortality Database, but little is known about coding quality and its impact on elderly unintentional fall mortality data worldwide. We aimed to assess the coding quality of deaths and its impact on elderly unintentional fall mortality. METHODS: Using data from the WHO Mortality Database, 1990-2019, we calculated the number of countries/territories that had mortality data in the database, and the proportion of deaths with five types of problematic codes based on the 10th International Classification of Disease (unspecified deaths, injury deaths with undetermined intent, unspecified unintentional injury, unintentional falls with unspecified mechanism, unintentional falls with unknown occurrence place). We estimated age-adjusted unintentional fall mortality before and after correcting problematic codes. RESULTS: Only 64% (124/194) of WHO member states had at least 1 year of mortality data in the database during 1990-2019, and data unavailability was more common for underdeveloped countries/territories than for developed countries/territories. Coding quality was poor for many countries/territories. Among the study years when countries/territories possessed mortality data, 80, 53, 51, and 63% had a proportion of unintentional fall deaths with unspecified mechanism over 50% in low-income, lower middle-income, upper middle-income, and high-income countries/territories, respectively; comparable proportions for unintentional fall deaths with unknown occurrence place were 100, 42, 71, and 62%. Among the 94 countries/territories having mortality data, problematic codes caused a relative mortality difference ≥ 50% in 59 countries/territories (63%). After correcting problematic codes, 5 of 55 countries/territories with data witnessed a reverse in mortality changes between 2005 and 2015. Among the 82 countries/territories with mortality data for 5 or more years, 18 countries/territories (22%) experienced a directional reverse in linear regression coefficient. CONCLUSIONS: The availability and coding quality of global data related to elderly unintentional fall mortality was poor between 1990 and 2019. When data are available, varying coding quality across countries/territories and over time have a substantial impact on mortality estimates and mortality comparisons. Global agencies plus each individual government should be aware of the importance of collecting and sharing high-quality mortality data, and take action to improve data quality for inclusion in the WHO Mortality Database.

Assessing the effectiveness of an app-based child unintentional injury prevention intervention for caregivers of rural Chinese preschoolers: protocol for a cluster randomized controlled trial.

BACKGROUND: Compared to urban children, children living in rural areas of most countries, including China, are at higher risk of suffering unintentional injuries. Most proven injury prevention interventions, however, are rarely implemented in rural China due to lack of resources. Mobile health interventions are low-cost and easy-to-implement, facilitating implementing injury prevention in resource-limited areas (e.g., rural areas). This study is designed and implemented to examine the effectiveness of an app-based intervention for unintentional injury prevention among rural preschoolers in China. METHODS: A single-blind, 18-month, parallel-group cluster randomized controlled trial with 1:1 allocation ratio will be implemented in 2 rural areas of China (Yang County, Shaanxi Province, and Shicheng County, Jiangxi Province). In total, at least 3508 rural caregivers of preschoolers aged 3-6 years old who own a smartphone will be recruited from 24 preschools. Clusters will be randomized at the preschool level and allocated to the control group (receiving routine school-based education plus app-based parenting education excluding unintentional injury prevention) or the intervention group (receiving routine school-based education plus app-based parenting education including unintentional injury prevention). External support strategies will be adopted by local partners to minimize user fatigue, non-compliance, and attrition. Data collection will be conducted at baseline and then every 3 months during the 18-month follow-up time period. Intention-to-treat data analysis will be implemented. Missing values will be imputed by using the Expectation Maximization algorithm. Generalized estimating equation will test the overall effectiveness of the app-based intervention. A per-protocol sensitivity analysis will be conducted to test the robustness of results. Subgroup analyses will follow the strategies for primary analyses. The primary outcome measure is the incidence rate of unintentional injury among preschoolers during the study period. Secondary outcome measures comprise longitudinal changes in caregiver's attitudes, caregiver-reported supervision behaviors, and caregiver-assessed home environment safety surrounding child unintentional injury prevention in the last week using a standardized audit instrument. DISCUSSION: The app-based intervention is expected to be feasible and effective over the 18-month intervention period. If the app is demonstrated effective as hypothesized, we will initiate processes to generalize and popularize it broadly to rural child caregivers across China. TRIAL REGISTRATION: ChiCTR2000037606 , registered on August 29, 2020.

Intestinal dysbacteriosis leads to kidney stone disease.

The formation and physicochemical properties of kidney stones (KSs) are closely associated with diet. In view of the differences in ethnicity and dietary composition between Chinese and Western populations, the present study aimed to investigate the association between intestinal dysbacteriosis and KSs in China. The current study examined the differences in intestinal microbes between the KS disease (KSD) and the healthy control (HLT) groups, and statistically significant differences based on 16s rRNA gene amplicons were identified using a Student's t­test or one­way ANOVA. In addition, the calcium oxalate KS (COKS), uric acid KS (UAKS) and carbonate apatite KS(CCKS) groups were compared with a non­parametric statistical test. Determination of bacterial abundance was performed via the analysis of 16s rRNA marker gene sequences using next­generation sequencing. Firmicutes (F) and Bacteroides (B) levels were significantly higher in the KSD group compared with the HLT group (B/F=0.67 vs. 0.08; P<0.001), as were the overall levels of B (6.19­fold higher compared with the HLT group; 22.2 vs. 3.6%; P<0.001). The Prevotella­9 abundance levels in the KSD group were 4.65­fold higher compared with those in the HLT group (8.8 vs. 1.9%; P<0.001). The levels of Blautia and Lachnoclostridium were significantly decreased in the KSD group (13.3 vs. 6.0%; and 5.0 vs. 7.9%; both P<0.05). Moreover, Prevotella­9 levels were higher in non­calciferous KSs (UAKS) compared with calciferous KSs (COKS and CCKS). Therefore, the findings of the present study indicated a key association between specific KS components and intestinal flora, providing a theoretical basis for new treatment methods for KSs. Moreover, differences and interactions between these bacteria could initially predict specific types of urolithiasis.

Efficient Iridium Catalysts for Formic Acid Dehydrogenation: Investigating the Electronic Effect on the Elementary ß-Hydride Elimination and Hydrogen Formation Steps.

We report herein a series of Cp*Ir complexes containing a rigid 8-aminoquinolinesulfonamide moiety as highly efficient catalysts for the dehydrogenation of formic acid (FA). The complex [Cp*Ir(L)Cl] (HL = N-(quinolin-8-yl)benzenesulfonamide) displayed a high turnover frequency (TOF) of 2.97 × 104 h-1 and a good stability (>100 h) at 60 °C. Comparative studies of [Cp*Ir(L)Cl] with the rigid ligand and [Cp*Ir(L')Cl] (HL' = N-propylpypridine-2-sulfonamide) without the rigid aminoquinoline moiety demonstrated that the 8-aminoquinoline moiety could dramatically enhance the stability of the catalyst. The electron-donating ability of the N,N'-chelating ligand was tuned by functionalizing the phenyl group of the L ligand with OMe, Cl, and CF3 to have a systematical perturbation of the electronic structure of [Cp*Ir(L)Cl]. Experimental kinetic studies and density functional theory (DFT) calculations on this series of Cp*Ir complexes revealed that (i) the electron-donating groups enhance the hydrogen formation step while slowing down the ß-hydride elimination and (ii) the electron-withdrawing groups display the opposite effect on these reaction steps, which in turn leads to lower optimum pH for catalytic activity compared to the electron-donating groups.

Factors Associated With Dropout of Participants in an App-Based Child Injury Prevention Study: Secondary Data Analysis of a Cluster Randomized Controlled Trial.

BACKGROUND: Mobile health (mHealth) interventions offer great potential to reach large populations and improve public health. However, high attrition rates threaten evaluation and implementation of mHealth intervention studies. OBJECTIVE: We explored factors associated with attrition of study participants in an mHealth randomized controlled trial (RCT) evaluating an intervention to reduce unintentional child injury risk in China. METHODS: The cluster RCT compared two groups of an app-based intervention for caregivers of 3-6-year-old children (Bao Hu San). The intervention group received unintentional child injury and parenting education, whereas only parenting education was implemented in the control group. The trial included 2920 study participants in Changsha, China, and lasted 6 months. Data on participant engagement (using the app) were collected electronically throughout the 6-month period. Associations between participant attrition and demographic characteristics, and between attrition and intervention engagement were tested and quantified separately for the intervention and control groups using the adjusted odds ratio (aOR) based on generalized linear mixed models. RESULTS: In total, 2920 caregivers from 20 eligible preschools participated, with 1510 in the intervention group and 1410 in the control group. The 6-month attrition rate differed significantly between the two groups (P<.001), at 28.9% (437/1510) in the intervention group and 35.7% (503/1410) in the control group. For the intervention group, the only significant predictor of attrition risk was participants who learned fewer knowledge segments (aOR 2.69, 95% CI 1.19-6.09). For the control group, significant predictors of attrition risk were lower monthly login frequency (aOR 1.48, 95% CI 1.00-2.18), learning fewer knowledge segments (aOR 1.70, 95% CI 1.02-2.81), and shorter learning durations during app engagement (aOR 2.39, 95% CI 1.11-5.15). Demographic characteristics were unrelated to attrition. CONCLUSIONS: Engagement in the app intervention was associated with participant attrition. Researchers and practitioners should consider how to best engage participants in app-based interventions to reduce attrition. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR-IOR-17010438; http://www.chictr.org.cn/showproj.aspx?proj=17376. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1186/s12889-018-5790-1.

Synergistic Effect of Pendant N Moieties for Proton Shuttling in the Dehydrogenation of Formic Acid Catalyzed by Biomimetic IrIII Complexes.

Formic acid (FA) is among the most promising hydrogen storage materials. The development of efficient catalysts for the dehydrogenation of FA via molecular-level control and precise tuning remains challenging. A series of biomimetic Ir complexes was developed for the efficient dehydrogenation of FA in an aqueous solution without base addition. A high turnover frequency of 46510 h-1 was achieved at 90 °C in 1 m FA solution with complex 1 bearing pendant pyridine. Experimental and mechanistic studies revealed that the integrated pendant pyridine and pyrazole moieties of complex 1 could act as proton relay and facilitate proton shuttling in the outer coordination sphere. This study provides a new strategy to control proton transfer accurately and a new principle for the design of efficient catalysts for FA dehydrogenation.

Ultrasmall Ni-ZnO/SiO2 Synergistic Catalyst for Highly Efficient Hydrogenation of NaHCO3 to Formic Acid.

Conversion of CO2 into fuels and chemicals has been considered to be an important strategy to reduce greenhouse gas emissions and alleviate the energy crisis. Bicarbonate as a CO2 source is convenient for experimental operation. Herein, based on the synergistic effect of Ni and ZnO benefitting from the electronic transfer, ultrasmall Ni-ZnO clusters (∼2 nm) stabilized by microporous silica nanoparticles were designed and prepared for catalyzing the hydrogenation of sodium bicarbonate to formic acid. The yield of formic acid reached up to 97.0% at 260 °C/3 MPa for 2 h, which is higher than those reported non-noble metal-based catalysts. The good performance of Ni-ZnO/SiO2 can be attributed to the ultrasmall active component size and the synergy effect based on electron transfer between Ni and ZnO.

Comprehensive characterization of immune- and inflammation-associated biomarkers based on multi-omics integration in kidney renal clear cell carcinoma.

BACKGROUND: Kidney renal clear cell carcinoma (KIRC) is the most common type of kidney cancer in adults, and it is responsible for approximately 90-95% of cases. Although extensive evidence has suggested that many immune- and inflammation-related genes could serve as effective biomarkers in KIRC, the potential associations among immune-, inflammation- and KIRC-related genes has not been sufficiently understood. METHODS: Here, we integrated multiple levels of data to construct an immune-, inflammation- or KIRC-directed neighbour network (IIKDN network) and a KIRC-related gene-directed network (KIRCD network). RESULTS: Our analysis suggested that immune- and inflammation-related genes in the network have special topological characteristics and expression patterns related to KIRC. We further identified five core clusters that showed a tighter network structure and stronger correlation of expression from the KIRCD network. Specifically, multiple-level molecular characteristics were systematically portrayed, including somatic mutation, copy-number variant and DNA methylation for the genes in five core clusters. We discovered that the genes showed strong correlation with respect to the expression and methylation levels in these five core clusters. These five core clusters could become special prognostic biomarkers for KIRC, and functional analysis showed that they were associated with activation of the immune and inflammation systems and cancer progression. CONCLUSIONS: Our findings highlighted the novel role of the immune and inflammation genes in KIRC.

Room temperature oxidative desulfurization with MoO3 subnanoclusters supported on MCM-41.

Subnano MoO3/MCM-41 was successfully prepared through doping (NH4)6Mo7O24 in the synthesis process of MCM-41. The morphology of MoO3/MCM-41 was visually observed by TEM and HADDF-STEM. N2 sorption, XPS and Raman were further applied to investigate the structure of the material. MoO3/MCM-41 was used in the oxidative desulfurization process with tert-butyl hydroperoxide as oxidant. MoO3/MCM-41 showed outstanding catalytic activity and recycling ability at room temperature.

MiR-216a exerts tumor-suppressing functions in renal cell carcinoma by targeting TLR4.

MiR-216a, a tumor-related microRNA (miRNA), has been reported to be implicated in the tumorigenesis and progression of diverse types of human malignancies; however, its role in renal cell carcinoma (RCC) remains unclear. This study aimed to explore the biological role of miR-216a in RCC and clarify the potential mechanisms involved. In the present study, miR-216a was found to be significantly down-regulated in both RCC tissues and cell lines. Functional studies demonstrated that enhanced expression of miR-216a suppressed RCC cell proliferation, migration and invasion in vitro, inhibited tumor growth in vivo, and induced RCC cell cycle arrest and apoptosis. Moreover, the tumor-suppressing effects of miR-216a in RCC were abrogated by the miR-216a inhibitor treatment. Notably, toll-like receptor 4 (TLR4) was downregulated by miR-216a via direct binding to its 3' untranslated region in RCC cells. Furthermore, TLR4 expression was discovered to be markedly up-regulated and inversely correlated with miR-216a expression in RCC tissues. Mechanistic studies revealed that restoring the expression of TLR-4 alleviated miR-216a-induced inhibitory effects on proliferation, migration and invasion of RCC cells. Taken together, these findings suggest that miR-216a functions as a tumor suppressor in RCC by directly targeting TLR4 and that miR-216a might be a novel therapeutic target for RCC.

CO2 Hydrogenation Catalyzed by Iridium Complexes with a Proton-Responsive Ligand.

The catalytic cycle for the production of formic acid by CO2 hydrogenation and the reverse reaction have received renewed attention because they are viewed as offering a viable scheme for hydrogen storage and release. In this Forum Article, CO2 hydrogenation catalyzed by iridium complexes bearing sophisticated N^N-bidentate ligands is reported. We describe how a ligand containing hydroxy groups as proton-responsive substituents enhances the catalytic performance by an electronic effect of the oxyanions and a pendent-base effect through secondary coordination sphere interactions. In particular, [(Cp*IrCl)2(TH2BPM)]Cl2 (Cp* = pentamethylcyclopentadienyl; TH2BPM = 4,4',6,6'-tetrahydroxy-2,2'-bipyrimidine) enormously promotes the catalytic hydrogenation of CO2 in basic water by these synergistic effects under atmospheric pressure and at room temperature. Additionally, newly designed complexes with azole-type ligands were applied to CO2 hydrogenation. The catalytic efficiencies of the azole-type complexes were much higher than that of the unsubstituted bipyridine complex [Cp*Ir(bpy)(OH2)]SO4. Furthermore, the introduction of one or more hydroxy groups into ligands such as 2-pyrazolyl-6-hydroxypyridine, 2-pyrazolyl-4,6-dihydroxypyrimidine, and 4-pyrazolyl-2,6-dihydroxypyrimidine enhanced the catalytic activity. It is clear that the incorporation of additional electron-donating functionalities into proton-responsive azole-type ligands is effective for promoting further enhanced hydrogenation of CO2.

Formic acid dehydrogenation with bioinspired iridium complexes: a kinetic isotope effect study and mechanistic insight.

Highly efficient hydrogen generation from dehydrogenation of formic acid is achieved by using bioinspired iridium complexes that have hydroxyl groups at the ortho positions of the bipyridine or bipyrimidine ligand (i.e., OH in the second coordination sphere of the metal center). In particular, [Ir(Cp*)(TH4BPM)(H2 O)]SO4 (TH4BPM: 2,2',6,6'-tetrahydroxyl-4,4'-bipyrimidine; Cp*: pentamethylcyclopentadienyl) has a high turnover frequency of 39 500 h(-1) at 80 °C in a 1 M aqueous solution of HCO2 H/HCO2 Na and produces hydrogen and carbon dioxide without carbon monoxide contamination. The deuterium kinetic isotope effect study clearly indicates a different rate-determining step for complexes with hydroxyl groups at different positions of the ligands. The rate-limiting step is ß-hydrogen elimination from the iridium-formate intermediate for complexes with hydroxyl groups at ortho positions, owing to a proton relay (i.e., pendent-base effect), which lowers the energy barrier of hydrogen generation. In contrast, the reaction of iridium hydride with a proton to liberate hydrogen is demonstrated to be the rate-determining step for complexes that do not have hydroxyl groups at the ortho positions.

Efficient water oxidation with organometallic iridium complexes as precatalysts.

Catalytic water oxidation has been investigated using five iridium complexes as precatalysts and NaIO4 as an oxidant at various pH conditions. An increase in the activity of all complexes was observed with increasing pH. A detailed analysis of spectroscopic data together with O2-evolution experiments using Cp*Ir(6,6'-dihydroxy-2,2'-bipyridine)(OH2)(2+) as a precatalyst indicate that the high catalytic activity is closely connected with transient species (A) that exhibits an absorption band at λmax 590 nm. The formation of this active form is strongly dependent on reaction conditions, and the species was distinctly observed using a small excess of periodate. However, another species absorbing at 600 nm (B), which seems to be a less active catalyst, was also observed and was more prominent at high oxidant concentration. Dynamic light scattering analysis and transmission electron microscopy have identified species B as 120 nm nanoparticles. The ultrafiltration method has revealed that species A can be attributed to particles with size in the range of 0.5­2 nm, possibly small IrOx clusters similar to those described previously by Harriman and co-workers (J. Phys. Chem., 1991, 95, 616­621).