In this review, the research conducted by the authors on anodic oxide films on aluminum is described, paying particular attention to how the electric field strength, as a factor other than voltage, ...controls the nanostructures and properties of the films. It will also be indicated what factors contribute to the formation of defects, which, in contrast to the ideal or model film structure, contains a significant number of defects in the film. In addition to electrochemical measurements, the films were examined with a variety of advanced instruments, including electron microscopes, to confirm the “reality of film nanostructure” from a slightly different angle than the conventional view. The following topics on anodic films formed in four types of major anodizing electrolytes are discussed: pore initiation process, steady-state porous structure, sealing mechanism, the relationship between cell parameters and voltage/electric field strength, amount and depth of anion incorporation, electrolyte types, radial branching of pores, atypical pore structures, defect formation mechanism, self-ordering, Al coordination number, and the creation of α-alumina membranes.
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•Sealing process of anodic alumina films was studied by advanced SEM, TEM and XPS.•In boiling water, boehmite precipitates as small flakes due to (100)-oriented growth.•As pore walls ...dissolve, boehmite flakes increase, forming an intertwined structure.•A three-layered sealing film with different densities of flaky boehmite is formed.•Neither preferential pore mouth closure nor uniform pore narrowing was identified.
The mechanism of the hot water sealing of anodic alumina films was studied using electron microscopy and compositional analysis. The films dissolve in boiling water and boehmite precipitates as small flakes due to (100)-oriented growth with 3-nm average thickness and evenly dispersing in the pores and the surface. The quantity and size of flakes increase with increasing sealing time forming a densely intertwined boehmite structure. Eventually, a three-layered structure is formed, which is composed of an outer vertically grown coarse flaky layer, an intermediate dense flaky layer with 2:1 thickness ratio, and a porous layer filled with dense flaky boehmite.
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•Nanostructures of anodic alumina films are studied by advanced analysis techniques.•The atypical pore structure of anode films can be classified into five categories.•The pores of ...common anodic films naturally grow with radially branched nanopores.•Initial small pores and radial nanopores are caused by a low electric field strength.•Radial branching of pores turned out to be universal, not unique to chromic acid film.
In this study, we use advanced analysis techniques to examine the nanostructures of anodic films formed on aluminum in various electrolytes, including oxalic acid and sulfuric acid, in the original state (without being chemically dissolved) and reveal that pores grow with radially branched nanopores. Nanopores are generated in the main pores for the same reason that initial small pores are generated on the film surface: nanopores are created when the electric field is reduced due to the presence of a thick barrier layer. These radially branched nanopores appear in a form characteristic of a film formed in chromic acid, producing a feather-like pore wall. As a representative model, the atypical porous structures created in the film formed in chromic acid were classified into five categories: initial small pores, branched pores, side holes, spherical voids, and radially branched nanopores. We demonstrate that these structures are not unique to chromic acid films but are a universal phenomenon, particularly radial nanobranching, which occurs naturally during the anodizing of most electrolytes.
•PEO coatings formed on AZ31B in various P:Si ratio electrolytes were studied.•The effect of P:Si ratio on the corrosion resistance was investigated.•Si-coating showed superior corrosion resistance ...to P-coating.•The highest corrosion resistance was achieved with a ratio of P:Si=20:80.
AZ31B magnesium alloy was treated by plasma electrolytic oxidation (PEO) in phosphate–silicate mixture electrolytes. The concentration ratio of phosphate to silicate was varied from 100:0 to 0:100 in order to investigate the influence of the electrolyte composition on the morphology, compositions and corrosion resistance of PEO coatings by using SEM, EDS, XRD, XPS analyses, immersion test, salt spray test and potentiodynamic polarization. When a mixture electrolyte with an optimum concentration ratio of phosphate to silicate (i.e. P:Si=20:80) is used, the corrosion resistance of PEO coatings is the highest.
Myxedema coma is a life-threatening and emergency presentation of hypothyroidism. However, the clinical features and outcomes of this condition have been poorly defined because of its rarity.
We ...conducted a retrospective observational study of patients diagnosed with myxedema coma from July 2010 through March 2013 using a national inpatient database in Japan. We investigated characteristics, comorbidities, treatments, and in-hospital mortality of patients with myxedema coma.
We identified 149 patients diagnosed with myxedema coma out of approximately 19 million inpatients in the database. The mean (standard deviation) age was 77 (12) years, and two-thirds of the patients were female. The overall proportion of in-hospital mortality among cases was 29.5%. The number of patients was highest in the winter season. Patients treated with steroids, catecholamines, or mechanical ventilation showed higher in-hospital mortality than those without. Variations in type and dosage of thyroid hormone replacement were not associated with in-hospital mortality. The most common comorbidity was cardiovascular diseases (40.3%). The estimated incidence of myxedema coma was 1.08 per million people per year in Japan. Multivariable logistic regression analysis revealed that higher age and use of catecholamines (with or without steroids) were significantly associated with higher in-hospital mortality.
The present study identified the clinical characteristics and outcomes of patients with myxedema coma using a large-scale database. Myxedema coma mortality was independently associated with age and severe conditions requiring treatment with catecholamines.
•Two-thirds of patients with myxedema coma were female, and the mean age was 77 years.•The mortality rate was 29.5%, and the incidence was 1.08/million people/year.•Older age and use of catecholamines, with or without steroids, were related to death.
Anodization by plasma electrolytic oxidation (PEO) and subsequent apatite coating were performed on a biodegradable AZ31 magnesium alloy to enhance its corrosion resistance and bioactivity in ...physiological solution. The PEO film itself (~48μm in thickness) exhibited low bioactivity, where only aggregated apatite particles were deposited locally on its surface as a result of the alternative immersion method (AIM) in Ca–phosphate solutions. The uniformity of apatite coating on the PEO film was markedly improved by pretreatment of the film in a dilute NaOH solution. The alkali treatment induced the formation of a nano-size platelet Mg(OH)2 layer on the film surfaces that drastically enlarged the effective surface area for the precipitation of apatite. A uniform apatite layer as thick as 1μm was successfully deposited on the hydroxide layer after AIM treatment. The enhanced uniformity of the apatite coating on an alkali- and AIM-treated surface significantly improved the corrosion resistance in both simulated body fluid (SBF) and NaCl solution, and the bioactivity in SBF.
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•Direct apatite coating applied on the PEO film of Mg alloy was unsuccessful.•Alkali treatment of PEO film markedly enhanced HA deposition by AIM.•HA pre-coated PEO film drastically improved bioactivity and corrosion resistance in SBF.
Current guidelines recommend routine nephropathy monitoring, including microalbuminuria or proteinuria testing, for people with diabetes mellitus; however, its effect in terms of preserving renal ...function remains unclear. We conducted this study to examine the impact of routine nephropathy monitoring on subsequent changes in estimated glomerular filtration rate.
We retrospectively identified non-elderly individuals with diabetes mellitus based on the prescription of hypoglycemic agents from a large Japanese database (JMDC, Tokyo, Japan) of screening for lifestyle diseases linked with administrative claims data. We collected data on baseline characteristics including age, sex, comorbidity, and laboratory data. We then examined the association between routine nephropathy monitoring results and change in estimated glomerular filtration rate using a propensity-score inverse probability of treatment weighting method.
Among 1,602 individuals who started taking hypoglycemic agents between 2005 and 2016, 102 (6.0%) underwent routine nephropathy monitoring during the first year of medication for diabetes mellitus. After adjusting for multiple confounding factors, there was no significant difference in subsequent estimated glomerular filtration rate changes between individuals with and without routine nephropathy monitoring (difference in percent change 0.11; 95% confidence interval -2.74 to 2.95).
Routine nephropathy monitoring was not associated with preserved renal function. Current recommendations for the universal application of nephropathy monitoring may have limited value to prevent renal dysfunction in non-elderly individuals with diabetes mellitus.
Direct comparative effectiveness of booster doses of BNT162b2 and mRNA-1273 after BNT162b2 primary vaccination is unknown.
We investigated comparative effectiveness of BNT162b2 and mRNA-1273 booster ...dose using data from registry systems for vaccination and coronavirus disease 2019 (COVID-19) infection in a local city in Japan. We followed participants aged ≥16 years who completed the BNT162b2 primary vaccination between 22 November 2021, and 15 April 2022. We collected information on age, sex, vaccination status, vaccine type, and infection status. Age was categorized as 16-44, 45-64, 65-84, and ≥85 years. Vaccine effectiveness for mRNA-1273 and no booster vaccination against BNT162b2 was estimated using age-stratified Cox regression adjusted for age, sex, and days since the second vaccination. The estimated hazard ratios for mRNA-1273 and no booster vaccinations were integrated separately using random effects meta-analyses.
During the study period, we identified 62 586 (40.4%), 51 490 (33.2%), and 40 849 (26.4%) participants who received BNT162b2, mRNA-1273, and no booster dose, respectively. The median age was 69, 71, and 47 years for BNT162b2, mRNA-1273, and no booster dose, respectively. The integrated hazard ratio with reference to BNT162b2 was 1.72 for no booster vaccination and 0.62 for mRNA-1273. The comparative effectiveness of mRNA-1273 was similar across age categories.
Both homologous and heterologous vaccinations are effective against Omicron variants. In the head-to-head comparison, the effect was stronger in people who received heterologous vaccination than in those who received homologous vaccination. These findings may help improve logistics and decision making in future vaccination programs.
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The thickness and corrosion resistance of films formed on AZ31 magnesium alloys through plasma electrolytic oxidation for the same amount of electricity supplied increased with ...decreasing electrolyte concentration irrespective of the current density. For all electrolytes of phosphate, silicate, and aluminate, the initial bending/breakdown voltage increased linearly with the logarithm of the decreasing electrolyte concentration and exhibited no dependence on the current density. The chemical composition of the films was independent of all electrolysis conditions such as electrolyte concentration, current density, and anodization time. This behavior is explained by a mechanism in which anion incorporation is governed by a chemical reaction/precipitation under plasma but not by the electric field, unlike the case for conventional anodizing of valve metals without sparking. The corrosion resistance of the films tended to increase as a function of the logarithm of the film thickness, irrespective of the electrolyte species and electrolysis conditions.
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