The “controlled” synthesis of metastable γ-Bi2O3 by solution based approaches was reported several times recently, but the formation of Bi12SiO20 in the presence of trace amounts of silicates renders ...the results to be questionable. Here, the preparation of the Sillenite γ-Bi2O3 and the Sillenite-type Bi12SiO20 starting from the polynuclear bismuth oxido cluster Bi38O45(O2CC3H5)24(DMSO)9 is reported. γ-Bi2O3 crystallizes after calcination at 800 °C of the silicate-free hydrolysis product “Bi38O45(OH)24” on a silver sheet. Corrosion of the substrate causes contamination with silver, which is not incorporated into the Bi–O lattice, and was removed by treatment with an aqueous KCN-solution. Bi12SiO20 was obtained after hydrothermal treatment of the bismuth oxido cluster in the presence of NaOH in glass vessels or Na2SiO3 in a Teflon-lined reactor vessel followed by calcination at 600 °C. PXRD studies, scanning electron microscopy, nitrogen adsorption measurements, IR- and Raman spectroscopy, diffuse UV–vis spectroscopy, and DSC were used for characterization. The phase transition of γ-Bi2O3 to give α-Bi2O3 occurred slowly in the temperature range of 348–510 °C (ΔH γ→α = 6.57 kJ·mol–1). The silver-containing γ-Bi2O3 exhibits slightly increased Raman modes compared to the silver-free sample due to the SERS effect. In the diffuse UV–vis spectrum γ-Bi2O3 exhibits an absorption edge at λ = 485 nm (E g = 2.76 eV), and the contamination with silver results in an additional absorption edge at λ = 572 nm. Silver-free γ-Bi2O3 exhibits an absorption edge at λ = 460 nm (E g = 2.83 eV) and Bi12SiO20 at λ = 422 nm (E g = 3.16 eV). The photocatalytic activity of the compounds was investigated in the decomposition of aqueous rhodamine B under visible light irradiation, showing silver-containing γ-Bi2O3 to be slightly more effective compared to Bi12SiO20 and significantly more effective than the silver-free γ-Bi2O3.
The 2017 World Workshop Classification system for periodontal and peri-implant diseases and conditions was developed in order to accommodate advances in knowledge derived from both biological and ...clinical research, that have emerged since the 1999 International Classification of Periodontal Diseases. Importantly, it defines clinical health for the first time, and distinguishes an intact and a reduced periodontium throughout. The term 'aggressive periodontitis' was removed, creating a staging and grading system for periodontitis that is based primarily upon attachment and bone loss and classifies the disease into four stages based on severity (I, II, III or IV) and three grades based on disease susceptibility (A, B or C). The British Society of Periodontology (BSP) convened an implementation group to develop guidance on how the new classification system should be implemented in clinical practice. A particular focus was to describe how the new classification system integrates with established diagnostic parameters and pathways, such as the basic periodontal examination (BPE). This implementation plan focuses on clinical practice; for research, readers are advised to follow the international classification system. In this paper we describe a diagnostic pathway for plaque-induced periodontal diseases that is consistent with established guidance and accommodates the novel 2017 classification system, as recommended by the BSP implementation group. Subsequent case reports will provide examples of the application of this guidance in clinical practice.
Aim This paper reports on one review of four rapid reviews undertaken to explore the relationships between oral health and general medical conditions, in order to support teams within Public Health ...England, health practitioners and policy makers. This review aimed to explore the most contemporary evidence on whether poor oral health and cardiovascular disease occurs in the same individuals or populations, to outline the nature of the relationship between these two health outcomes and to discuss the implication of any findings for health services and future research.Methods The review was undertaken by a group comprising consultant clinicians from medicine and dentistry, trainees, public health and academics. The methodology involved a streamlined rapid review process and synthesis of the data.Results The results identified a number of systematic reviews of low to high quality, which suggests that there is: (1) fairly robust evidence of an increased risk of atherosclerotic vascular disease (ASVD) amongst individuals with chronic periodontitis, independent of other established cardiovascular risk factors; (2) there is some evidence that the incidence of caries and tooth loss is higher in patients with cardiovascular disease; and (3) that orofacial pain can presents as the sole symptom of stroke in some patients. The findings are discussed in relation to implications for service and future research.Conclusion There is high quality evidence to support an association between cardiovascular disease and oral health. This evidence is mainly related to the association between chronic periodontitis and atherosclerotic heart disease, and is independent of confounding factors as drawn from epidemiological observational studies.
We introduce a direct aqueous synthesis of luminescent 2-3 nm Ag-In-Se (AISe) quantum dots (QDs) capped by glutathione (GSH) complexes, where sodium selenosulfate Na
2
SeSO
3
is used as a stable Se
...2−
precursor. A series of size-selected AISe QDs with distinctly different positions of absorption and PL bands can be separated from the original QD ensembles by using anti-solvent-induced size-selective precipitation. The AISe-GSH QDs emit broadband PL with the band maximum varying from 1.65 eV (750 nm) to 1.90 eV (650 nm) depending on the average QD size and composition. The PL quantum yield varies strongly with basic synthesis parameters (ratios of constituents, Zn addition, duration of thermal treatment,
etc.
) reaching 4% for "core" AISe and 12% for "core/shell" AISe/ZnS QDs. The shape and position of PL bands is interpreted in terms of the model of radiative recombination of a self-trapped exciton. The AISe-GSH QDs reveal phonon Raman spectra characteristic for small and Ag-deficient tetragonal Ag-In-Se QDs. The ability of ultra-small AISe QDs to support such "bulk-like" vibrations can be used for future deeper insights into structural and optical properties of this relatively new sort of QDs.
A direct aqueous synthesis, composition- and size-dependent absorption, photoluminescence, and vibrational properties of ultra-small glutathione-capped Ag-deficient Ag-In-Se quantum dots are reported.
ABSTRACT
The detection of the optical transient AT2017gfo proved that binary neutron star mergers are progenitors of kilonovae (KNe). Using a combination of numerical-relativity and ...radiative-transfer simulations, the community has developed sophisticated models for these transients for a wide portion of the expected parameter space. Using these simulations and surrogate models made from them, it has been possible to perform Bayesian inference of the observed signals to infer properties of the ejected matter. It has been pointed out that combining inclination constraints derived from the KN with gravitational-wave measurements increases the accuracy with which binary parameters can be estimated, in particular breaking the distance-inclination degeneracy from gravitational wave inference. To avoid bias from the unknown ejecta geometry, constraints on the inclination angle for AT2017gfo should be insensitive to the employed models. In this work, we compare different assumptions about the ejecta and radiative reprocesses used by the community and we investigate their impact on the parameter inference. While most inferred parameters agree, we find disagreement between posteriors for the inclination angle for different geometries that have been used in the current literature. According to our study, the inclusion of reprocessing of the photons between different ejecta types improves the modeling fits to AT2017gfo and, in some cases, affects the inferred constraints. Our study motivates the inclusion of large ∼ 1-mag uncertainties in the KN models employed for Bayesian analysis to capture yet unknown systematics, especially when inferring inclination angles, although smaller uncertainties seem appropriate to capture model systematics for other intrinsic parameters. We can use this method to impose soft constraints on the ejecta geometry of the KN AT2017gfo.
The aim of this study was to investigate the association between cigarette smoking and smoking cessation and the prevalence and incidence of tooth loss in a large cohort study in Germany. We analyzed ...data of 23,376 participants of the European Prospective Investigation into Cancer and Nutrition (EPIC)–Potsdam study recruited between 1994 and 1998 from the general population in Potsdam and other parts of Brandenburg, Germany, who had complete data on cigarette smoking, tooth loss, and covariates. Negative binomial regression and tooth-specific logistic regression models were fit to evaluate the association between smoking and the baseline prevalence and incidence of tooth loss during follow-up, respectively. Cigarette smoking was associated with higher prevalence of tooth loss at baseline as well as higher incidence of tooth loss during follow-up. The association between smoking and the incidence of tooth loss was stronger in men than women and stronger in younger versus older individuals. Heavy smoking (≥15 cigarettes/d) was associated with >3 times higher risk of tooth loss in men (odds ratio, 3.6; 95% confidence interval, 3.0, 4.4) and more than twice the risk of tooth loss in women (odds ratio, 2.5; 95% confidence interval, 2.1, 2.9) younger than 50 y when compared with never smokers. Smoking cessation was consistently associated with a reduction in tooth loss risk, with the risk of tooth loss approaching that of never smokers after approximately 10 to 20 y of cessation.
Abstract
Structure, composition, and optical properties of colloidal mercaptoacetate-stabilized Cu
2
ZnSnS
4
(CZTS) nanocrystal inks produced by a “green” method directly in aqueous solutions were ...characterized. A size-selective precipitation procedure using 2-propanol as a non-solvent allows separating a series of fractions of CZTS nanocrystals with an average size (bandgap) varying from 3 nm (1.72 eV) to 2 nm (2.04 eV). The size-selected CZTS nanocrystals revealed also phonon confinement, with the main phonon mode frequency varying by about 4 cm
−1
between 2 nm and 3 nm NCs.
In this work, we developed a method to study in situ the optical properties of Cu2–x Se and CuS nanocrystals upon electrochemical reduction and oxidation. Both these materials possess a strong ...localized surface plasmon resonance (LSPR) in the near-infrared region. First, the nanoparticles were embedded into a transparent film made of a perfluorinated sulfonic-acid copolymer Nafion deposited onto an ITO-coated glass. This substrate was employed as a working electrode for chronoamperometry and cyclic voltammetry measurements directly in a transparent cell allowing for simultaneous acquisition of absorption spectra of the system upon its charging/discharging. We observed that LSPR of the Cu2–x Se NCs can be well-controlled and tuned in a wide range simply by potentiostatic potential switching. Starting with an intensive plasmon of the initial as-synthesized Cu2–x Se NCs we were able to completely damp it via reduction (electron injection). Moreover, this electrochemical tuning was demonstrated to be reversible by subsequent oxidation (extracting electrons from the system). At the same time, CuS NCs did not exhibit such prominent LSPR modulation upon the same experimental conditions due to their more metallic-like electronic structure. Hence, our findings demonstrate for the first time a reversible tuning of the LSPR of copper chalcogenide NCs without any chemical or structural modification. Such a wide LSPR tunability is of paramount importance, for example in applications of these materials in photovoltaics to amplify light absorption, in systems involving plasmon–exciton interactions to controllably quench/enhance light emission, and in electrochromic devices to control their transmittance.
Conjugated polymers featuring tunable band gaps/positions and tailored active centers, are attractive photoelectrode materials for water splitting. However, their exploration falls far behind their ...inorganic counterparts. Herein, we demonstrate a molecular engineering strategy for the tailoring aromatic units of conjugated acetylenic polymers from benzene‐ to thiophene‐based. The polarized thiophene‐based monomers of conjugated acetylenic polymers can largely extend the light absorption and promote charge separation/transport. The C≡C bonds are activated for catalyzing water reduction. Using on‐surface Glaser polycondensation, as‐fabricated poly(2,5‐diethynylthieno3,2‐bthiophene) on commercial Cu foam exhibits a record H2‐evolution photocurrent density of 370 μA cm−2 at 0.3 V vs. reversible hydrogen electrode among current cocatalyst‐free organic photocathodes (1–100 μA cm−2). This approach to modulate the optical, charge transfer, and catalytic properties of conjugated polymers paves a critical way toward high‐activity organic photoelectrodes.
Photoelectrode materials for water splitting: As‐fabricated poly(2,5‐diethynylthieno3,2‐bthiophene) on Cu foam exhibits a record H2‐evolution photocurrent density of 370 μA cm−2 at 0.3 V vs. reversible hydrogen electrode, in comparison to current cocatalyst‐free organic photocathodes (1–100 μA cm−2), during water splitting. This paves a critical way towards the development of high‐activity organic photoelectrodes.
In Europe cardiovascular disease (CVD) is responsible for 3.9 million deaths (45% of deaths), being ischaemic heart disease, stroke, hypertension (leading to heart failure) the major cause of these ...CVD related deaths. Periodontitis is also a chronic non-communicable disease (NCD) with a high prevalence, being severe periodontitis, affecting 11.2% of the world's population, the sixth most common human disease.
There is now a significant body of evidence to support independent associations between severe periodontitis and several NCDs, in particular CVD. In 2012 a joint workshop was held between the European Federation of Periodontology (EFP) and the American Academy of Periodontology to review the literature relating periodontitis and systemic diseases, including CVD. In the last five years important new scientific information has emerged providing important emerging evidence to support these associations.
The present review reports the proceedings of the workshop jointly organised by the EFP and the World Heart Federation (WHF), which has updated the existing epidemiological evidence for significant associations between periodontitis and CVD, the mechanistic links and the impact of periodontal therapy on cardiovascular and surrogate outcomes. This review has also focused on the potential risk and complications of periodontal therapy in patients on anti thrombotic therapy and has made recommendations for dentists, physicians and for patients visiting both the dental and medical practices.
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