The importance of various sediment components in the oxidation of As(III) (arsenite) to As(V) (arsenate) by freshwater lake sediments in southern Saskatchewan was examined. Treating the sediments with hydroxylamine hydrochloride or sodium acetate to remove Mn greatly decreased the oxidation of As(III). Furthermore, synthetic Mn(IV) oxide was a very effective oxidant with respect to As(III): 216 µg As(V)/ml was formed in solution when 1000 µg As(III)/ml was added to suspensions of 0.1 g of the oxide. These results indicate that Mn in the sediment was probably the primary electron acceptor in the oxidation of As(III). The conversion of As(III) to As(V) by naturally occurring carbonate and silicate minerals common in sediments was not evident in the system studied. Sediment particles >20 µm in size are the least effective in oxidizing As(III); the oxidizing ability of the 5–20-, 2–5-, and <2-µm particle size fractions varies depending on the sediment. The concentration of As(V) in equilibrated solutions after adding increasing amounts of As(III) (as much as 100 µg/ml) to 1 g of the three sediments ranged from approximately 3.5 to 19 µg/ml. Because As(III) is more toxic and soluble than As(V), Mn-bearing components of both the colloidal and non-colloidal fractions of the sediments may potentially detoxify any As(III) that may enter aquatic environments by converting it to As(V). This is very important in reducing the As contamination and in maintaining the ecological balance in aquatic environments.

Ultrafast optical probing is a widely used method of underdense plasma diagnostic. In relativistic plasma, the motion blur limits spatial resolution in the direction of motion. For many high-power lasers the initial pulse duration of 30–50 fs results in a 10–15 μm motion blur, which can be reduced by probe pulse post-compression. Here we used the compression after compressor approach [Phys.-Usp. 62, 1096 (2019); JINST 17 P07035 (2022)], where spectral broadening is performed in thin optical plates and is followed by reflections from negative-dispersion mirrors. Our initially low-intensity probe beam was down-collimated for a more efficient spectral broadening and higher probe-to-self-emission intensity ratio. The setup is compact, fits in a vacuum chamber and can be implemented within a short experimental time slot. We proved that the compressed pulse retained the high quality necessary for plasma probing.

OBJECTIVES/GOALS: The 'field effect' is a concept in pathology that pre-malignant tissue changes forecast health. Spatial transcriptomics could detect these changes earlier than histopathology, suggesting new early cancer screening methods. Knowing how normal tissue damage relates to cancer’s origin and progression may improve long-term outcomes. METHODS/STUDY POPULATION: We trained DEGAS, our machine learning framework, with prostate cancer data, combining both general cancer patterns and in-depth genetic information from individual tumors. The Tumor Cancer Genome Atlas (TCGA) shows how gene patterns in tumors relate to patient outcomes, emphasizing the differences between tumors from different patients (intertumor). On the other hand, spatial transcriptomics (ST) shows the genetic variety within a single tumor (intratumor) but has limited samples, making it hard to know which genetic differences are important for treatment. DEGAS bridges these areas by finding tissue sections that resemble those in TCGA profiles and are key indicators of patient survival. DEGAS serves as a valuable tool for generating clinically-important hypotheses. RESULTS/ANTICIPATED RESULTS: DEGAS identified benign-appearing glands in a normal prostate as being highly associated with poor progression-free survival. These glands have transcriptional signatures similar to high-grade prostate cancer. We confirmed this finding in a separate prostate cancer ST dataset. By integrating single cell (SC) data we demonstrated that cells annotated as cancerous in the SC data map to regions of benign glands in the ST dataset. We pinpoint several genes, chiefly Microseminoprotein-β (MSMB, PSP94), where reduced expression is highly correlated with poor progression-free survival. Cell type specific differential expression analysis further revealed that loss of MSMB expression associated with poor outcomes occurs specifically in luminal epithelia, the putative progenitor of prostate cancer. DISCUSSION/SIGNIFICANCE: DEGAS reveals that normal-appearing tissue can be highly-associated with tumor progression and underscores the importance of the 'field effect' in cancer research. Traditional analysis may miss such nuance, hiding key transitional cell states. Validating gene markers could boost early cancer detection and understanding of metastasis.

Reactions between hydroxy-Al ions and orthosilicic acid as influenced by citric acid were studied at an initial Si concentration of 1.6 × 10−3 M, Si/Al molar ratios of 0.5 and 1.0, OH/Al molar ratios of 1.0-3.0, and citric acid/Al molar ratios of 0-0.3. In the absence of citric acid and at OH/A1 ratios of 1.0-2.8, imogolite (>0.01 μm) was dominant in the precipitates. At citric acid/Al ratios of 0.01-0.1, imogolite and/or pseudoboehmite were dominant in the precipitates at OH/Al ratios of 1.0 and 2.0, and imogolite and/or ill-defined aluminosilicate complexes at OH/Al ratio of 2.8. Instead of allophane or “proto-imogolite” allophane being the predominant species in the precipitates, the formation of ill-defined aluminosilicate complexes at OH/Al ratio of 3.0 was steadily promoted by increasing the solution citric acid/Al ratios from 0 to 0.3. The freeze-dried soluble products (<0.01 μ) ranged from silica gel to “proto-imogolite,” depending upon the basicity of Al and the level of citric acid of the parent solution. The amount of “proto-imogolite” increased with increasing citric acid/Al ratios from 0 to 0.1 in solution. Complexing low molecular weight organic acids, such as citric acid, impeded the formation of the short-range ordered aluminosilicates, allophanes and imogolite.

From 2020 to December 2022, China implemented strict measures to contain the spread of severe acute respiratory syndrome coronavirus 2. However, despite these efforts, sustained outbreaks of the Omicron variants occurred in 2022. We extracted COVID-19 case numbers from May 2021 to October 2022 to identify outbreaks of the Delta and Omicron variants in all provinces of mainland China. We found that omicron outbreaks were more frequent (4.3 vs. 1.6 outbreaks per month) and longer-lasting (mean duration: 13 vs. 4 weeks per outbreak) than Delta outbreaks, resulting in a total of 865,100 cases, of which 85% were asymptomatic. Despite the average Government Response Index being 12% higher (95% confidence interval (CI): 9%, 15%) in Omicron outbreaks, the average daily effective reproduction number (Rt) was 0.45 higher (95% CI: 0.38, 0.52, p < 0.001) than in Delta outbreaks. Omicron outbreaks were suppressed in 32 days on average (95% CI: 26, 39), which was substantially longer than Delta outbreaks (14 days; 95% CI: 11, 19; p = 0.004). We concluded that control measures effective against Delta could not contain Omicron outbreaks in China. This highlights the need for continuous evaluation of new variants’ epidemiology to inform COVID-19 response decisions.

We evaluated whether universal chlorhexidine bathing (decolonization) with or without COVID-19 intensive training impacted COVID-19 rates in 63 nursing homes (NHs) during the 2020–2021 Fall/Winter surge. Decolonization was associated with a 43% lesser rise in staff case-rates (P < .001) and a 52% lesser rise in resident case-rates (P < .001) versus control.

Polynuclear Al13 tridecamer species are the major hydrolyzed species of aluminum, but their occurrence in terrestrial environments has not been established. X-ray diffraction (XRD), 27Al nuclear magnetic resonance (NMR), and scanning electron microscope (SEM) analyses show that the presence of tartaric acid (concentration range of 10−5–10−3 M), one of the commonly occurring low-molecular-weight organic acids, inhibits the formation of the Al13 tridecamer species.

In the absence of tartaric acid, the basic aluminum sulfate crystals were of tetrahedral morphology and conformed to isometric symmetry with a = 17.748 Å and space group of P4232. Increasing amounts of tartaric acid [tartaric acid/Al molar ratio (R) ranging from 0.01 to 0.05] modified the crystal morphology from the tetrahedral particles of isometric symmetry (R = 0) to rod-shaped particles of monoclinic symmetry (R = 0.01) to irregularly shaped X-ray noncrystalline microparticles (R = 0.05). Failure to detect the presence of Al13 tridecamer, the dominant hydrolyzed species of aluminum, in terrestrial environments may be partially attributed to the presence of low-molecular-weight organic acids, which inhibit the formation of Al13 tridecamer species.

This investigation was carried out to study the effect of different concentrations of citric acid and glycine, which are common in freshwaters, on the kinetics of the adsorption of Hg by kaolinite under various pH conditions. The data indicate that Hg adsorption by kaolinite at different concentrations of citric acid and glycine obeyed multiple first order kinetics. In the absence of the organic acids, the rate constants of the initial fast process were 46 to 75 times faster than those of the slow adsorption process in the pH range of 4.00 to 8.00. Citric acid had a significant retarding effect on both the fast and slow adsorption process at pHs of 6.0 and 8.0. It had a significant promoting effect on the fast and slow adsorption process at pH 4.00. Glycine had a pronounced enhancing effect on the rate of Hg adsorption by kaolinite during the fast process. The rise in pH of the system further increased the effect of glycine on Hg adsorption. The magnitude of the retarding/promoting effect upon the rate of Hg adsorption was evidently dependent upon the pH, structure and functionality of organic acids, and molar ratio of the organic acid/Hg. The data obtained suggest that low-molecular-weight organic acids merit close attention in studying the kinetics and mechanisms of the binding of Hg by sediment particulates and the subsequent food chain contamination.

The chemistry of Al transformation has been well documented, though little is known about the mechanisms of structural perturbation of Al precipitates by carbonates at a molecular level. The purpose of the present study was to investigate the structural perturbation of Al precipitates formed under the influence of carbonates. Initial carbonate/Al molar ratios (MRs) used were 0, 0.1, and 0.5 after aging for 32 days, then the samples were analyzed by X-ray absorption near edge structure spectroscopy (XANES), X-ray diffraction (XRD), Fourier-transform infrared absorption spectroscopy (FTIR), and chemical analysis. The XRD data were in accord with the FTIR results, which revealed that as the carbonate/Al MR was increased from 0 to 0.1, carbonate preferentially retarded the formation of gibbsite and had relatively little effect on the formation of bayerite. As the carbonate/Al MR was increased to 0.5, however, the crystallization of both gibbsite and bayerite was completely inhibited. The impact of carbonate on the nature of Al precipitates was also evident in the increase of adsorbed water and inorganic C contents with increasing carbonate/Al MR. The Al K- and L- edge XANES data provide the first evidence illustrating the change in the coordination number of Al from 6-fold to mixed 6- and 4-fold coordination in the structural network of short-range ordered (SRO) Al precipitates formed under the increasing perturbation of carbonate. The fluorescence yield spectra of the O K-edge show that the intensity of the peak at 534.5 eV assigned to σ* transitions of Al-O and O-H bonding decreased with increasing carbonate/Al MR. The XANES data, along with the evidence from XRD, FTIR, and chemical analysis showed clearly that carbonate caused the alteration of the coordination nature of the Al-O bonding through perturbation of the atomic bonding and structural configuration of Al hydroxides by complexation with Al in the SRO network of Al precipitates. The surface reactivity of an Al-O bond is related to its covalency and coordination geometry. The present findings were, therefore, of fundamental significance in understanding the low-temperature geochemistry of Al and its impacts on the transformation, transport, and fate of nutrients and pollutants in the ecosystem.

The Al13 polycation is the predominant hydroxy-Al species in partially neutralized solutions. However, the existence of the Al13 species and the factors governing its formation in terrestrial environments still remain obscure. The objective of this study was to investigate the influence of pyrogallol, a common polyphenol in soils, on the formation of Al13 tridecamer. Hydroxy-Al solutions with an OH/Al molar ratio of 2.2 (pH 4.53) at pyrogallol/Al molar ratios of 0, 0.01, 0.05, 0.1 and 0.5 were prepared and mixed with 0.5 M sodium sulfate to form aluminum sulfate precipitation products. The solid-state 27Al nuclear magnetic resonance (NMR) spectra of the precipitates show that the pyrogallol perturbed the formation of Al13 tridecamer species as indicated by the decrease in the intensity of resonance peak, observed at 62.5 ppm, with increase in the pyrogallol/Al molar ratio. The crystallization of the precipitated Al sulfates was also hampered by pyrogallol, resulting in the formation of X-ray non-crystalline products at a pyrogallol/Al molar ratio of 0.50. The absorbance at 465 and 650 nm of the hydroxy-Al-pyrogallol solutions, the C coprecipitated, the electron spin resonance and 13C CPMAS-NMR spectra of the precipitates indicate the concomitant enhanced abiotic humification of pyrogallol by the X-ray amorphous Al species.

The influence of organics on the crystallization of Al precipitates has been well documented. However, the effects of organics and ageing on the transformation and structural configuration of Al precipitates in relation to their surface and charge properties are not fully understood. This study investigated the structural, microporous and surface properties of Al precipitates formed under the influence of tannate and ageing. The Al precipitates were synthesized at an initial Al concentration of 7 × 10−3 M, an OH/Al molar ratio (MR) of 3.0, and initial tannate/Al MRs of 0, 0.001, 0.01 and 0.1, and aged for 1, 10 and 40 days. As indicated by a decrease in gibbsite and bayerite and an increase in the oxalate-extractable Al contents, the non-crystalline precipitates increased with the increase of the initial tannate/Al MR. This observation is in accord with the X-ray diffraction and Fourier transform infrared (FTIR) data. The impact of tannic acid on the nature of the Al precipitates is also reflected in the increase of the contents of the pyrophosphate-extractable Al, which is indicative of organically bound Al. This observation is in agreement with the increase in the intensity of characteristic FTIR absorption bands of tannate and the organic C and adsorbed water contents. The decrease in the crystallinity of Al precipitates with increase in the tannate/Al MR resulted in the development of microporosity, increase in BET specific surface area and decrease of the average pore diameter and point of zero salt effect (PZSE). The FTIR absorption bands characteristic of tannate of the Al precipitates became weaker with ageing, in accord with the ageing-induced decrease in the contents of organic C and pyrophosphate-extractable Al. Ageing drastically decreased the BET specific surface area of the Al precipitates formed in the absence of tannate but this effect was less conspicuous for the products formed at the tannate/Al molar ratio of 0.1. The ageing-induced change in the PZSE of the Al precipitates formed both in the absence and presence of tannate was not significant. The results accomplished in this study are of fundamental significance to our understanding of the combined effects of organics and ageing on structural configuration of hydrolytic precipitates of Al in relation to their microporosity, surface and charge properties in the environment.