Ureolytic CaCO3 precipitation for immobilization of arsenic in an aquifer system

The objective of this study was to precipitate CaCO3in a groundwater media to reduce dissolved arsenic concentrations. In this study a mixture of ureolytic calcite and aragonite were precipitated using groundwater as the media. Although precipitation of carbonate was successful using Ardkenneth groundwater, arsenic concentrations were not reduced. Ureolytic calcite and aragonite precipitated using broth as the media and resulted in a decrease in arsenic concentrations of up to 88% from the initial 0.7 μg L-1 concentration. Ureolytic carbonate precipitation required the inoculation of ureolytic cultures isolated from groundwater into both the groundwater and broth media. Precipitates in the inoculation experiments were identified using infrared spectroscopy techniques.The decrease in arsenic concentrations in the inoculated urea treated broth samples compared to the groundwater samples was attributed to the greater amounts of precipitate formed in the broth media. The broth had a free Ca(II) concentration of 1300 mg L-1 whereas the Ardkenneth groundwater had a free Ca(II) concentration of 36 to 42 mg L-1. The higher free Ca(II) concentrations in the broth media would account for the higher yield of carbonate precipitate, making Ca(II) concentration a limiting factor in ureolytic CaCO3 remediation techniques. Formation of a visible precipitate required the addition of nitrate to the broth and groundwater samples. The inoculated cultures, being denitrifiers, required a nitrate source. Ca(II) ion concentrations decreased in the different media without the addition of nitrate, but no visible precipitate formed. Laboratory experiments using Ardkenneth groundwater and treatments of 0.03 M urea did not decrease the Ca(II) ion concentrations or reduce arsenic in solution. These results suggest that inoculation with selected ureolytic cultures was needed to optimize the precipitation of CaCO3 in a natural groundwater system. The results of this study suggest that arsenic was reduced by the precipitation of ureolytic CaCO3. Arsenic reduced by ureolytic CaCO3 precipitation required adequate levels of Ca(II) ions, higher than those found in the Ardkenneth aquifer. Successful precipitation of CaCO3 by ureolytic organisms also required an adequate cell density. Thus, inoculation with ureolytic cultures optimized the broth and groundwater media for CaCO3 precipitation

The burden of self-reported antibiotic allergies in health care and how to address it: A systematic review of the evidence

Background: Antibiotics are the first-line treatment for bacterial infections; however, overuse and inappropriate prescribing have made antibiotics less effective with increased antimicrobial resistance. Unconfirmed reported antibiotic allergy labels create a significant barrier to optimal antimicrobial stewardship in health care, with clinical and economic implications. Objective: A systematic review was conducted to summarize the impact of patient-reported antibiotic allergy on clinical outcomes and various strategies that have been employed to effectively assess and remove these allergy labels, improving patient care. Methods: The review was undertaken using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A critical appraisal was conducted on all studies and a narrative synthesis was performed to identify themes. Results: Four themes emerged: the prevalence of antibiotic allergy, impact of antibiotic allergy on antimicrobial prescribing, impact of antibiotic allergy on clinical outcomes, and delabeling strategies to improve clinical outcomes. Of the 32 studies, including 1,089,675 participants, the prevalence of reported antibiotic allergy was between 5% and 35%. Patients with a reported antibiotic allergy had poorer concordance with prescribing guidelines in 30% to 60% of cases, with a higher use of alternatives such as quinolone, tetracycline, macrolide, lincosamide, and carbapenem and lower use of beta-lactam antibiotics. Antibiotic allergy delabeling was identified as an intervention and recommendation to advance the state of the science. Conclusions: There is substantial evidence within the literature that antibiotic allergy labels significantly impact patient clinical outcomes and a consensus that systematic assessment of reported antibiotic allergies, commonly referred to as delabeling, improves the clinical management of patients

Exploring transparency: a new framework for responsible business management

The purpose of this paper is to critically review the relevant literature on transparency, provide a comprehensive definition of transparency, and present a new framework for facilitating the adoption of transparency as an ethical cornerstone and pragmatic strategy for organizational responsible business management.Ye

Dinuclear Ce(IV) Aryloxides: Highly Active Catalysts for Anhydride/Epoxide Ring-Opening Copolymerization

A library of new dinuclear CeIV complexes of the type [NEt4]2[Ce2X6(TP)(sol)2] (X = Cl, ODipp, OSiMe3; sol = py, THF), where TP represents a family of tetraphenolate ligands that control intermetallic distance, are readily made in good yields. The ligands strongly stabilize the cerium +4 oxidation state and allow the incorporation of alkylammonium cocations in an "ate"complex formulation that enables them to be used as soluble, single-component catalysts for the ring-opening copolymerization (ROCOP) of a variety of anhydrides and epoxides. High turnover frequencies (TOFs) are achieved with high ester linkage selectivity, low dispersities, and rates that are highly tunable by the intermetallic distance enforced by the TP ligand, demonstrating that a closely coupled di-CeIV unit provides excellent rates of ROCOP catalysis and that, more generally, rare-earth complexes deserve further attention as ROCOP initiators

Effects of Within-Person Variability in Spot Urinary Sodium Measurements on Associations With Blood Pressure and Cardiovascular Disease.

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The Effects of Anodal Stimulation of the Left Prefrontal Cortex on Sentence Production

Most studies in which Anodal Transcranial Direct Current Stimulation (A-tDCS) has been used to improve language production have focused on single words. Yet sentence production requires more than lexical retrieval. For example, successful suppression of the past and careful planning of the future are two critical requirements for producing a correct sentence. Can A-tDCS improves those, and by extension, production at the sentence level

HIV-2 Encephalitis: Case Report and Literature Review

We report the case of a 59-year-old man who moved from Cape Verde to Massachusetts at the age of 29. He had multiple sexual contacts with female partners in Cape Verde and with West African women in Massachusetts, as well as multiple past indeterminate HIV-1 antibody tests. He presented to our facility with 2–3 months of inappropriate behaviors, memory impairment, weight loss, and night sweats, at which time he was found to have an abnormal enhancing lesion of the corpus collosum on brain magnetic resonance imaging (MRI). Laboratory testing revealed a CD4 count of $63 cells/mm^3$, positive HIV-2 Western blot, serum HIV-2 RNA polymerase chain reaction (PCR) of 1160 copies per milliliter and cerebrospinal fluid (CSF) HIV-2 RNA PCR of 2730 copies per milliliter. Brain biopsy demonstrated syncytial giant cells centered around small blood vessels and accompanied by microglia, which correlated with prior pathologic descriptions of HIV-2 encephalitis and with well-described findings of HIV-1 encephalitis. Based on genotype resistance assay results, treatment guidelines, and prior studies validating success with lopinavir-ritonavir, he was treated with tenofovir-emtricitabine and lopinavir-ritonavir, which has led to virologic suppression along with steady neurologic and radiologic improvement, although he continues to have deficits

Diversity-Oriented Enzymatic Synthesis of Cyclopropane Building Blocks

While biocatalysis is increasingly incorporated into drug development pipelines, it is less commonly used in the early stages of drug discovery. By engineering a protein to produce a chiral motif with a derivatizable functional handle, biocatalysts can be used to help generate diverse building blocks for drug discovery. Here we show the engineering of two variants of Rhodothermus marinus nitric oxide dioxygenase (RmaNOD) to catalyze the formation of cis- and trans-diastereomers of a pinacolboronate-substituted cyclopropane which can be readily derivatized to generate diverse stereopure cyclopropane building blocks

Diversity-Oriented Enzymatic Synthesis of Cyclopropane Building Blocks

While biocatalysis is increasingly incorporated into drug development pipelines, it is less commonly used in the early stages of drug discovery. By engineering a protein to produce a chiral motif with a derivatizable functional handle, biocatalysts can be used to help generate diverse building blocks for drug discovery. Here we show the engineering of two variants of Rhodothermus marinus nitric oxide dioxygenase (RmaNOD) to catalyze the formation of cis- and trans-diastereomers of a pinacolboronate-substituted cyclopropane which can be readily derivatized to generate diverse stereopure cyclopropane building blocks