Colloidal Atomic Layer Deposition on Nanocrystals Using Ligand-Modified Precursors.

Atomic layer deposition (ALD) is a method to grow thin metal oxide layers on a variety of materials for applications spanning from electronics to catalysis. Extending ALD to colloidally stable nanocrystals promises to combine the benefits of thin metal oxide coatings with the solution processability of the nanocrystals. However, challenges persist in applying this method, which relate to finding precursors that promote the growth of the metal oxide while preserving colloidal stability throughout the process. Herein, we introduce a colloidal ALD method to coat nanocrystals with amorphous metal oxide shells using metal and oxygen precursors that act as colloidal stabilizing ligands. Our scheme involves metal-amide precursors modified with solubilizing groups and oleic acid as the oxygen source. The growth of the oxide is self-limiting and proceeds in a layer-by-layer fashion. Our protocol is generalizable and intrinsically scalable. Potential applications in display, light detection, and catalysis are envisioned.

Burden of osteoarthritis in India and its states, 1990-2019: findings from the Global Burden of disease study 2019.

OBJECTIVE: To describe the burden of osteoarthritis (OA) in India from 1990 to 2019. DESIGN: Data from Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 were used. The burden of OA -knee OA, hip OA, hand OA, and other OA- was estimated for India and its states from 1990 to 2019 through a systematic analysis of prevalence, incidence, years lived with disability (YLD), and disability-adjusted life years (DALY) using methods reported in GBD 2019 study. RESULT: Around 23.46 million individuals in India had OA in 1990; this increased to 62.35 million in 2019. The age-standardised prevalence of OA increased from 4,895 (95% uncertainty interval (UI):4,420-5,447) in 1990-5313 (95%UI:4,799-5,898) in 2019, per 100,000 persons. Similarly, DALYs due to OA increased from 0.79 million (95%UI:0.40-1.55) to 2.12 million (95%UI:1.07-4.23); while age-standardised DALYs increased from 164 (95%UI:83-325) to 180 (95%UI:91-361) per 100,000 persons from 1990 to 2019. OA was the 20th most common cause of YLDs in India in 2019, accounting for 1.48% (95%UI:0.88-2.78) of all YLDs; increasing from 23rd most common cause in 1990 (1.25%(95%UI:0.74-2.34)). Knee OA was the most common form of OA, followed by hand OA. The prevalence, incidence, and DALYs for OA and knee OA were consistently higher in females than males. CONCLUSION: The burden and impact of OA in India are substantial and is increasing. Adopting suitable control and preventive community measures to reduce modifiable risk factors (obesity, injuries, occupational stress) are needed to reduce the current and future burden of OA in India.

Resonant nanodiffraction x-ray imaging reveals role of magnetic domains in complex oxide spin caloritronics.

Spin electronic devices based on crystalline oxide layers with nanoscale thicknesses involve complex structural and magnetic phenomena, including magnetic domains and the coupling of the magnetism to elastic and plastic crystallographic distortion. The magnetism of buried nanoscale layers has a substantial impact on spincaloritronic devices incorporating garnets and other oxides exhibiting the spin Seebeck effect (SSE). Synchrotron hard x-ray nanobeam diffraction techniques combine structural, elemental, and magnetic sensitivity and allow the magnetic domain configuration and structural distortion to be probed in buried layers simultaneously. Resonant scattering at the Gd L2 edge of Gd3Fe5O12 layers yields magnetic contrast with both linear and circular incident x-ray polarization. Domain patterns facet to form low-energy domain wall orientations but also are coupled to elastic features linked to epitaxial growth. Nanobeam magnetic diffraction images reveal diverse magnetic microstructure within emerging SSE materials and a strong coupling of the magnetism to crystallographic distortion.

Operando potassium K-edge X-ray absorption spectroscopy: investigating potassium catalysts during soot oxidation.

The chemical and structural nature of potassium compounds involved in catalytic soot oxidation have been studied by a combination of temperature programmed oxidation and operando potassium K-edge X-ray absorption spectroscopy experiments. These experiments are the first known operando studies using tender X-rays (∼3.6 keV) under high temperature oxidation reaction conditions. X-ray absorption near edge structure analysis of K2CO3/Al2O3 catalysts during heating shows that, at temperatures between 100 and 200 °C, potassium species undergo a structural change from an initial hydrated K2CO3·xH2O and KHCO3 mixture to well-defined K2CO3. As the catalyst is heated from 200 °C to 600 °C, a feature associated with multiple scattering shifts to lower energy, indicating increased K2CO3 dispersion, due to its mobility at high reaction temperature. This shift was noted to be greater in samples containing soot than in control experiments without soot and can be attributed to enhanced mobility of the K2CO3, due to the interaction between soot and potassium species. No potassium species except K2CO3 could be defined during reactions, which excludes a potential reaction mechanism in which carbonate ions are the active soot-oxidising species. Simulations of K-edge absorption near edge structures were performed to rationalise the observed changes seen. Findings showed that cluster size, unit cell distortions and variation in the distribution of potassium crystallographic sites influenced the simulated spectra of K2CO3. While further simulation studies are required for a more complete understanding, the current results support the hypothesis that changes in the local structure on dispersion can influence the observed spectra. Ex situ characterisation was carried out on the fresh and used catalyst, by X-ray diffraction and X-ray photoelectron spectroscopy, which indicated changes to the carbonate species, in line with the X-ray absorption spectroscopy experiments.

In situ K-edge X-ray absorption spectroscopy of the ligand environment of single-site Au/C catalysts during acetylene hydrochlorination.

The replacement of HgCl2/C with Au/C as a catalyst for acetylene hydrochlorination represents a significant reduction in the environmental impact of this industrial process. Under reaction conditions atomically dispersed cationic Au species are the catalytic active site, representing a large-scale application of heterogeneous single-site catalysts. While the metal nuclearity and oxidation state under operating conditions has been investigated in catalysts prepared from aqua regia and thiosulphate, limited studies have focused on the ligand environment surrounding the metal centre. We now report K-edge soft X-ray absorption spectroscopy of the Cl and S ligand species used to stabilise these isolated cationic Au centres in the harsh reaction conditions. We demonstrate the presence of three distinct Cl species in the materials; inorganic Cl-, Au-Cl, and C-Cl and how these species evolve during reaction. Direct evidence of Au-S interactions is confirmed in catalysts prepared using thiosulfate precursors which show high stability towards reduction to inactive metal nanoparticles. This stability was clear during gas switching experiments, where exposure to C2H2 alone did not dramatically alter the Au electronic structure and consequently did not deactivate the thiosulfate catalyst.

XMaS @ the ESRF.

This paper describes the motivation for the design and construction of a beamline at the European Synchrotron Radiation Facility (ESRF) for the use of UK material scientists. Although originally focused on the study of magnetic materials, the beamline has been running for 20 years and currently supports a very broad range of science as evidenced by the research topics highlighted in this article. We describe how the beamline will adapt to align with the ESRF's upgrade to a diffraction limited storage ring. This article is part of the theme issue 'Fifty years of synchrotron science: achievements and opportunities'.

NEXAFS spectroscopy of ionic liquids: experiments versus calculations.

Experimental near edge X-ray absorption fine structure (NEXAFS) spectra are reported for 12 ionic liquids (ILs) encompassing a range of chemical structures for both the sulfur 1s and nitrogen 1s edges and compared with time-dependent density functional theory (TD-DFT) calculations. The energy scales for the experimental data were carefully calibrated against literature data. Gas phase calculations were performed on lone ions, ion pairs and ion pair dimers, with a wide range of ion pair conformers considered. For the first time, it is demonstrated that TD-DFT is a suitable method for simulating NEXAFS spectra of ILs, although the number of ions included in the calculations and their conformations are important considerations. For most of the ILs studied, calculations on lone ions in the gas phase were sufficient to successfully reproduce the experimental NEXAFS spectra. However, for certain ILs - for example, those containing a protic ammonium cation - calculations on ion pairs were required to obtain a good agreement with experimental spectra. Furthermore, significant conformational dependence was observed for the protic ammonium ILs, providing insight into the predominant liquid phase cation-anion interactions. Among the 12 investigated ILs, we find that four have an excited state that is delocalised across both the cation and the anion, which has implications for any process that depends on the excited state, for example, radiolysis. Considering the collective experimental and theoretical data, we recommend that ion pairs should be the minimum number of ions used for the calculation of NEXAFS spectra of ILs.

Atomic charges of sulfur in ionic liquids: experiments and calculations.

Experimental near edge X-ray absorption fine structure (NEXAFS) spectra, X-ray photoelectron (XP) spectra and Auger electron spectra are reported for sulfur in ionic liquids (ILs) with a range of chemical structures. These values provide experimental measures of the atomic charge in each IL and enable the evaluation of the suitability of NEXAFS spectroscopy and XPS for probing the relative atomic charge of sulfur. In addition, we use Auger electron spectroscopy to show that when XPS binding energies differ by less than 0.5 eV, conclusions on atomic charge should be treated with caution. Our experimental data provides a benchmark for calculations of the atomic charge of sulfur obtained using different methods. Atomic charges were computed for lone ions and ion pairs, both in the gas phase (GP) and in a solvation model (SMD), with a wide range of ion pair conformers considered. Three methods were used to compute the atomic charges: charges from the electrostatic potential using a grid based method (ChelpG), natural bond orbital (NBO) population analysis and Bader's atoms in molecules (AIM) approach. By comparing the experimental and calculated measures of the atomic charge of sulfur, we provide an order for the sulfur atoms, ranging from the most negative to the most positive atomic charge. Furthermore, we show that both ChelpG and NBO are reasonable methods for calculating the atomic charge of sulfur in ILs, based on the agreement with both the XPS and NEXAFS spectroscopy results. However, the atomic charges of sulfur derived from ChelpG are found to display significant, non-physical conformational dependence. Only small differences in individual atomic charge of sulfur were observed between lone ion (GP) and ion pair IL(SMD) model systems, indicating that ion-ion interactions do not strongly influence individual atomic charges.

Origin of spray formation during impact on heated surfaces.

In many applications, it is crucial to control the heat transfer rate of impacting drops on a heated plate. When the solid exceeds the so-called Leidenfrost temperature, an impacting drop is prevented from contacting the plate by its own evaporation. But the decrease in the resulting cooling efficiency of the impacting drop is yet not quantitatively understood. Here, we experimentally study the impact of such water drops on smooth heated surfaces of various substances. We demonstrate that, in contrast to previous results for other liquids, water exhibits spray in the vertical direction when impacting sapphire and silicon. We show that this typical spray formation during impact is a result of the local cooling of the plate. This is surprising since these two materials were considered to remain isothermal during the impact of mm-sized droplets. We conclude and explain that the thermal time scale of the system is not solely determined by the thermal properties of the solid, but also by those of the liquid. We also introduce a dimensionless number comparing the thermal time scale and the dynamic time scale with which we can predict the spraying behaviour at impact.

ARHGAP29 Mutation Is Associated with Abnormal Oral Epithelial Adhesions.

Nonsyndromic cleft lip and/or palate (NSCL/P) is a prevalent birth defect of complex etiology. Previous studies identified mutations in ARHGAP29 associated with an increased risk for NSCL/P. To investigate the effects of ARHGAP29 in vivo, we generated a novel murine allele by inserting a point mutation identified in a patient with NSCL/P. This single-nucleotide variation of ARHGAP29 translates to an early nonsense mutation (K326X), presumably resulting in loss-of-function (LoF). Embryos from Arhgap29K326X/+ intercrosses were harvested at various time points. No homozygous Arhgap29K326X animals were found in the 45 analyzed litters, assessed as early as embryonic day 8.5 (e8.5). Coronal sectioning of e13.5 and e14.5 heads revealed that 59% of Arhgap29K326X/+ mice ( n = 37) exhibited improper epithelial contact between developing oral structures, while none were observed in wild types ( n = 10). In addition, Arhgap29K326X/+ embryos exhibited a significantly higher percentage of maxillary epithelium in contact with mandibular epithelium. Immunofluorescent analyses of the periderm and oral adhesions revealed the presence of Arhgap29 in periderm cells. These cells were p63 negative, keratin 17 positive, and keratin 6 positive and present at sites of adhesion, although occasionally disorganized. Oral adhesions did not appear to impair palatogenesis, as all analyzed Arhgap29K326X/+ embryos showed confluent palatal mesenchyme and epithelium at e18.5 ( n = 16), and no mice were found with a cleft at birth. Collectively, our data demonstrate that ARHGAP29 is required for embryonic survival and that heterozygosity for LoF variants of Arhgap29 increases the incidence and length of oral adhesions at a critical time point during orofacial development. In conclusion, we validate the LoF nature of the human K326X mutation in vivo and reveal a previously unknown effect of Arhgap29 in murine craniofacial development.

X-ray spectroscopy for chemistry in the 2-4 keV energy regime at the XMaS beamline: ionic liquids, Rh and Pd catalysts in gas and liquid environments, and Cl contamination in γ-Al2O3.

The 2-4 keV energy range provides a rich window into many facets of materials science and chemistry. Within this window, P, S, Cl, K and Ca K-edges may be found along with the L-edges of industrially important elements from Y through to Sn. Yet, compared with those that cater for energies above ca. 4-5 keV, there are relatively few resources available for X-ray spectroscopy below these energies. In addition, in situ or operando studies become to varying degrees more challenging than at higher X-ray energies due to restrictions imposed by the lower energies of the X-rays upon the design and construction of appropriate sample environments. The XMaS beamline at the ESRF has recently made efforts to extend its operational energy range to include this softer end of the X-ray spectrum. In this report the resulting performance of this resource for X-ray spectroscopy is detailed with specific attention drawn to: understanding electrostatic and charge transfer effects at the S K-edge in ionic liquids; quantification of dilution limits at the Cl K- and Rh L3-edges and structural equilibria in solution; in vacuum deposition and reduction of [Rh(I)(CO)2Cl]2 to γ-Al2O3; contamination of γ-Al2O3 by Cl and its potential role in determining the chemical character of supported Rh catalysts; and the development of chlorinated Pd catalysts in `green' solvent systems. Sample environments thus far developed are also presented, characterized and their overall performance evaluated.

Canine olfactory detection of malignant melanoma.

Our patient is a 75-year-old man who presented after his pet dog licked persistently at an asymptomatic lesion behind his right ear. Examination revealed a nodular lesion in the postauricular sulcus. Histology confirmed malignant melanoma, which was subsequently excised. Canine olfactory detection of human malignancy is a well-documented phenomenon. Advanced olfaction is hypothesised to explain canine detection of bladder, breast, colorectal, lung, ovarian, prostate and skin cancers. Further research in this area may facilitate the development of a highly accurate aid to diagnosis for many malignancies, including melanoma.

Intravenous glomus tumour of the upper arm.

Glomus tumours are rare, benign tumours of the glomus body, most frequently located in the subungual region of digits, palms and soles, but they have been reported throughout the body. Our patient is a 65-year-old man who presented with a 3-year history of a very painful area on his left upper arm. The overlying skin was normal and there was no lesion to palpate, but the symptoms were very striking, warranting further investigation. An exploratory operation identified a prominent vein with a noticeable bulge in the vessel wall. The vein was ligated and excised. On dissection of the vein, a tumour was present within its lumen. Histological examination and immune profile of the tumour confirmed an intravascular glomus tumour. Following surgical excision, symptoms resolved.

Efficacy and safety of leflunomide alone and in combination with methotrexate in the treatment of refractory rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis patients who develop refractoriness are left with no alternatives other than leflunomide and costly biological response modifiers. Leflunomide, though effective, was associated with adverse events and has not been extensively studied in the Indian population. AIMS: Determination of safety and efficacy of leflunomide alone and if not useful, in combination with methotrexate in patients refractory to conventional disease-modifying agents. SETTING AND DESIGN: Open labeled clinical trial with leflunomide [100 mg, OD x 3 days followed by 20 mg, OD x 6 months], if no improvement at three months, combined with methotrexate [5-7.5 mg, OD x 3 months] at a tertiary care hospital. MATERIALS AND METHODS: The primary endpoint in the improvement in EULAR criteria and secondary endpoints were patient and physician global evaluation, incidence of remission and biochemical and clinical adverse events. STATISTICAL ANALYSIS: Chi square test or Fisher's exact test and parametric and non-parametric repeat measure ANOVA were used for analysis. RESULTS: Among 84 patients who were included in the study, leflunomide showed improvement and remission in 52 [62%] and 6 [7%] in six months, by intention to treat analysis. Adverse events were observed in 15, discontinuation in 5 and 24 dropped out. With combination in 11 patients, there was improvement and remission in nine [91%] and one [9%] after three months. Adverse events were observed in six and one discontinued. CONCLUSIONS: If regular monitoring of hepatic function and hematological parameters are performed, leflunomide is an effective and safe drug in the Indian population in resistant rheumatoid arthritis patients, especially if used alone.

Once-monthly administration of darbepoetin alfa for the treatment of patients with chronic heart failure and anemia: a pharmacokinetic and pharmacodynamic investigation.

In patients with chronic heart failure (CHF), anemia is associated with more severe symptoms and worse prognosis. Erythropoiesis-stimulating proteins (ESPs) increase hemoglobin and may be of therapeutic benefit. We investigated the pharmacokinetics and pharmacodynamics of the long-acting ESP, darbepoetin alfa, administered on 2 occasions 1 month apart to 30 healthy subjects and 33 patients with symptomatic CHF and anemia (hemoglobin

Association of hemoglobin levels with clinical outcomes in acute coronary syndromes.

BACKGROUND: In the setting of an acute coronary syndrome (ACS), anemia has the potential to worsen myocardial ischemia; however, data relating anemia to clinical outcomes in ACS remain limited. METHODS AND RESULTS: We examined the association between baseline hemoglobin values and major adverse cardiovascular events through 30 days in 39,922 patients enrolled in clinical trials of ACS. After adjustment for differences in baseline characteristics and index hospitalization treatments, a reverse J-shaped relationship between baseline hemoglobin values and major adverse cardiovascular events was observed. In patients with ST-elevation myocardial infarction, when those with hemoglobin values between 14 and 15 g/dL were used as the reference, cardiovascular mortality increased as hemoglobin levels fell below 14 g/dL, with an adjusted OR of 1.21 (95% CI 1.12 to 1.30, P<0.001) for each 1-g/dL decrement in hemoglobin. At the other end of the range of hemoglobin, patients with hemoglobin values >17 g/dL also had excess mortality (OR 1.79, 95% CI 1.18 to 2.71, P=0.007). In patients with non-ST-elevation ACS, with those with hemoglobin 15 to 16 g/dL used as the reference, the likelihood of cardiovascular death, myocardial infarction, or recurrent ischemia increased as the hemoglobin fell below 11 g/dL, with an adjusted OR of 1.45 (95% CI 1.33 to 1.58, P<0.001) for each 1 g/dL decrement in hemoglobin. Patients with hemoglobin values >16 g/dL also had an increased rate of death or ischemic events (OR 1.31, 95% CI 1.03 to 1.66, P=0.027). CONCLUSIONS: Anemia is a powerful and independent predictor of major adverse cardiovascular events in patients across the spectrum of ACS.

Anemia and its relationship to clinical outcome in heart failure.

BACKGROUND: Anemia is often observed in patients with chronic heart failure (CHF), but its implications for patient outcomes are not well understood. The goal of this study was to investigate the relationship between anemia, severity of CHF, and clinical outcomes. METHODS AND RESULTS: Hemoglobin concentration (Hb) was measured in 912 subjects with CHF enrolled in the Randomized Etanercept North American Strategy to Study Antagonism of Cytokines (RENAISSANCE) trial. In a subgroup of 69 subjects, cardiac MRI was performed at randomization and 24 weeks later. Anemia (Hb < or =12.0 g/dL) was present in 12% of subjects. Cox regression analysis indicated that for every 1-g/dL-higher baseline Hb, the risk of mortality was 15.8% lower (P=0.0009) and the risk of mortality or hospitalization for heart failure was 14.2% lower (P<0.0001). Greater CHF severity was associated with significantly lower Hb concentrations. An increase in Hb over time was associated with a decrease in left ventricular mass and lower mortality, whereas a decrease in Hb over time was associated with an increase in left ventricular mass and higher mortality. In multivariate analysis, anemia remained a significant, independent predictor of death or hospitalization for heart failure, with both outcomes being significantly higher in all NYHA classes. CONCLUSIONS: Anemia is frequently present in patients with CHF. Lower Hb is associated with greater disease severity, a greater left ventricular mass index, and higher hospitalization and mortality rates.

Anti-inflammatory strategies in coronary atherosclerosis.

Recent evidence has demonstrated that inflammation plays an important role in the progression of coronary atherosclerosis. This review focuses on acute coronary syndromes and examines some novel therapeutic strategies aimed at manipulating the inflammatory environment in these patients in order to reduce the subsequent major adverse coronary event rate following myocardial infarction.

Simultaneous detection of different glycosidase activities by 19F NMR spectroscopy.

A fast method for the simultaneous detection of different glycosidolytic activities in commercially available enzyme preparations and crude culture filtrates was found in using, as substrate, a mixture of different glycosyl fluorides and 19F NMR spectroscopy as a screening technique. Accompanying studies regarding the hydrolytic stability of these fluorides in various buffer systems, as well as conditions of their long-term storage, were carried out. A simple procedure for the preparation of beta-D-mannopyranosyl fluoride in gram quantities is given.