FTIR Study of Copper Agglomeration during Atomic Layer Deposition of Copper

The growth of of metallic copper by atomic layer deposition (ALD) using copper(I) di-sec-butylacetamidinate $([Cu(^sBu-amd)]_2)$ and molecular hydrogen $(H_2)$ on $SiO_2/Si$ surfaces has been studied. The mechanisms for the initial surface reaction and chemical bonding evolutions with each ALD cycle are inferred from in situ Fourier transform infrared spectroscopy (FTIR) data. Spectroscopic evidence for Cu agglomeration on $SiO_2$ is presented involving the intensity variations of the $SiO_2$ LO/TO phonon modes after chemical reaction with the Cu precursor and after the $H_2$ precursor cycle. These intensity variations are observed over the first 20 ALD cycles at 185°C.Chemistry and Chemical Biolog

In-situ Infrared Characterization During Atomic Layer Deposition of Lanthanum Oxide

Mechanisms of atomic layer deposition (ALD) growth of lanthanum oxide on H-terminated Si(111) using lanthanum tris(N,N′-diisopropylacetamidinate) (La(iPr-MeAMD)3) are investigated using infrared (IR) absorption spectroscopy. The reactivity of this amidinate precursor is high, with almost all surface Si−H bonds consumed after 5 ALD cycles at 300 °C. Gas phase IR spectra show that, although most of the precursor (La(iPr-MeAMD)3) remains intact, a strong feature at 1665 cm−1, characteristic of a hydrogenated and dissociated free ligand with localized electrons in the N−CN bonds, is present. Such partial precursor dissociation in the gas phase is due to hydrolysis by traces of water vapor remaining in the reactor, even after purging. As a result, some Si−O−La bonds are formed upon reaction with the surface during the first La(iPr-MeAMD)3 pulse, prior to any water pulse. During film growth, acetate/carbonate and hydroxyl impurities are incorporated into the film. Annealing to 500 °C in dry N2 removes these impurities but fosters the growth of interfacial SiO2. Deposition at 300 °C leads to decomposition of adsorbed ligands, as evidenced by the formation of cyanamide or carbodiimide vibrational bands (or both) at 1990 and 2110 cm−1, respectively. Despite this decomposition, ideal self-limited ALD growth is maintained because the decomposed ligands are removed by the subsequent water pulse. Growth of pure lanthanum oxide films is often characterized by nonuniform film thickness if purging is not complete because of reversible absorption of water by the La2O3 film. Uniform ALD growth can be maintained without a rigorous dry purge by introducing alternating trimethylaluminum (TMA)/D2O ALD cycles between La/D2O cycles.Chemistry and Chemical Biolog

Novel Bacterial Diversity and Fragmented eDNA Identified in Hyperbiofilm-Forming Pseudomonas aeruginosa Rugose Small Colony Variant

Pseudomonas aeruginosa biofilms represent a major threat to health care. Rugose small colony variants (RSCV) of P. aeruginosa, isolated from chronic infections, display hyperbiofilm phenotype. RSCV biofilms are highly resistant to antibiotics and host defenses. This work shows that RSCV biofilm aggregates consist of two distinct bacterial subpopulations that are uniquely organized displaying contrasting physiological characteristics. Compared with that of PAO1, the extracellular polymeric substance of RSCV PAO1ΔwspF biofilms presented unique ultrastructural characteristics. Unlike PAO1, PAO1ΔwspF released fragmented extracellular DNA (eDNA) from live cells. Fragmented eDNA, thus released, was responsible for resistance of PAO1ΔwspF biofilm to disruption by DNaseI. When added to PAO1, such fragmented eDNA enhanced biofilm formation. Disruption of PAO1ΔwspF biofilm was achieved by aurine tricarboxylic acid, an inhibitor of DNA-protein interaction. This work provides critical novel insights into the contrasting structural and functional characteristics of a hyperbiofilm-forming clinical bacterial variant relative to its own wild-type strain

Ichthyofauna of the Mangrove Ecosystem

The mangroves are breeding, nursery, feeding and hiding grounds for a certain group of finfish, crustacea and shellfish among the aquatic fauna and include those which enter from the sea as well as those which migrate down from the upstream stretches of rivers. An inventory of the ichthyofauna of the mangrove ecosystems has been prepared as part of a NATP project to assess the biodiversity

Strict inequalities of critical values in continuum percolation

We consider the supercritical finite-range random connection model where the points $x,y$ of a homogeneous planar Poisson process are connected with probability $f(|y-x|)$ for a given $f$. Performing percolation on the resulting graph, we show that the critical probabilities for site and bond percolation satisfy the strict inequality $p_c^{\rm site} > p_c^{\rm bond}$. We also show that reducing the connection function $f$ strictly increases the critical Poisson intensity. Finally, we deduce that performing a spreading transformation on $f$ (thereby allowing connections over greater distances but with lower probabilities, leaving average degrees unchanged) {\em strictly} reduces the critical Poisson intensity. This is of practical relevance, indicating that in many real networks it is in principle possible to exploit the presence of spread-out, long range connections, to achieve connectivity at a strictly lower density value.Comment: 38 pages, 8 figure

FTIR study of copper agglomeration during atomic layer deposition of copper

ABSTRACT The growth of of metallic copper by atomic layer deposition (ALD) using copper(I) di-secbutylacetamidinate ([Cu

Recommendations for repositories and scientific gateways from a neuroscience perspective

Digital services such as repositories and science gateways have become key resources for the neuroscience community, but users often have a hard time orienting themselves in the service landscape to find the best fit for their particular needs. INCF (International Neuroinformatics Coordinating Facility) has developed a set of recommendations and associated criteria for choosing or setting up and running a repository or scientific gateway, intended for the neuroscience community, with a FAIR neuroscience perspective. These recommendations have neurosciences as their primary use case but are often general. Considering the perspectives of researchers and providers of repositories as well as scientific gateways, the recommendations harmonize and complement existing work on criteria for repositories and best practices. The recommendations cover a range of important areas including accessibility, licensing, community responsibility and technical and financial sustainability of a service.Comment: 10 pages, submitted to Scientific Dat

Dialysis Initiation in Patients With Chronic Coronary Disease and Advanced Chronic Kidney Disease in ISCHEMIA-CKD

BACKGROUND: In participants with concomitant chronic coronary disease and advanced chronic kidney disease (CKD), the effect of treatment strategies on the timing of dialysis initiation is not well characterized. METHODS AND RESULTS: In ISCHEMIA‐CKD (International Study of Comparative Health Effectiveness With Medical and Invasive Approaches–Chronic Kidney Disease), 777 participants with advanced CKD and moderate or severe ischemia were randomized to either an initial invasive or conservative management strategy. Herein, we compare the proportion of randomized participants with non–dialysis‐requiring CKD at baseline (n=362) who initiated dialysis and compare the time to dialysis initiation between invasive versus conservative management arms. Using multivariable Cox regression analysis, we also sought to identify the effect of invasive versus conservative chronic coronary disease management strategies on dialysis initiation. At a median follow‐up of 23 months (25th–75th interquartile range, 14–32 months), dialysis was initiated in 18.9% of participants (36/190) in the invasive strategy and 16.9% of participants (29/172) in the conservative strategy (P=0.22). The median time to dialysis initiation was 6.0 months (interquartile range, 3.0–16.0 months) in the invasive group and 18.2 months (interquartile range, 12.2–25.0 months) in the conservative group (P=0.004), with no difference in procedural acute kidney injury rates between the groups (7.8% versus 5.4%; P=0.26). Baseline clinical factors associated with earlier dialysis initiation were lower baseline estimated glomerular filtration rate (hazard ratio [HR] associated with 5‐unit decrease, 2.08 [95% CI, 1.72–2.56]; P<0.001), diabetes (HR, 2.30 [95% CI, 1.28–4.13]; P=0.005), hypertension (HR, 7.97 [95% CI, 1.09–58.21]; P=0.041), and Hispanic ethnicity (HR, 2.34 [95% CI, 1.22–4.47]; P=0.010). CONCLUSIONS: In participants with non–dialysis‐requiring CKD in ISCHEMIA‐CKD, randomization to an invasive chronic coronary disease management strategy (relative to a conservative chronic coronary disease management strategy) is associated with an accelerated time to initiation of maintenance dialysis for kidney failure

Correlations in the chemical composition of rural background atmospheric aerosol in the UK determined in real time using time-of-flight mass spectrometry

An aerosol time-of-flight mass spectrometer (ATOFMS) was used to determine, in real time, the size and chemical composition of individual particles in the atmosphere at the remote inland site of Eskdalemuir, Scotland. A total of 51980 particles, in the size range 0.3–7.4 µm, were detected between the 25th and 30th June 2001. Rapid changes in the number density, size and chemical composition of the atmospheric aerosol were observed. These changes are attributed to two distinct types of air mass; a polluted air mass that had passed over the British mainland before reaching Eskdalemuir, interposed between two cleaner air masses that had arrived directly from the sea. Such changes in the background aerosol could clearly be very important to studies of urban aerosols and attempts at source apportionment. The results of an objective method of data analysis are presented. Correlations were sought between the occurrence of: lithium, potassium, rubidium, caesium, beryllium, strontium, barium, ammonium, amines, nitrate, nitrite, boron, mercury, sulfate, phosphate, fluorine, chlorine, bromine, iodine and carbon (both elemental and organic hydrocarbon) in both fine (d 2.5 µm) particle fractions. Several previously unreported correlations were observed, for instance between the elements lithium, beryllium and boron. The results suggest that about 2 in 3 of all fine particles (by number rather than by mass), and 1 in 2 of all coarse particles containing carbon, consisted of elemental carbon rather than organic hydrocarbon (although a bias in the sensitivity of the ATOFMS could have affected these numbers). The ratio of the number of coarse particles containing nitrate anions to the number of particles containing chloride anions exceeded unity when the air mass had travelled over the British mainland. The analysis also illustrates that an air mass of marine origin that had travelled slowly over agricultural land can accumulate amines and ammonium

Polygenic Parkinson's Disease Genetic Risk Score as Risk Modifier of Parkinsonism in Gaucher Disease

Background: Biallelic pathogenic variants in GBA1 are the cause of Gaucher disease (GD) type 1 (GD1), a lysosomal storage disorder resulting from deficient glucocerebrosidase. Heterozygous GBA1 variants are also a common genetic risk factor for Parkinson's disease (PD). GD manifests with considerable clinical heterogeneity and is also associated with an increased risk for PD. Objective: The objective of this study was to investigate the contribution of PD risk variants to risk for PD in patients with GD1. Methods: We studied 225 patients with GD1, including 199 without PD and 26 with PD. All cases were genotyped, and the genetic data were imputed using common pipelines. Results: On average, patients with GD1 with PD have a significantly higher PD genetic risk score than those without PD (P = 0.021). Conclusions: Our results indicate that variants included in the PD genetic risk score were more frequent in patients with GD1 who developed PD, suggesting that common risk variants may affect underlying biological pathways. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA