Separation of Dissolved Organic Matter (DOM) and Per- and Polyfluoro-Alkyl Substances (PFAS) from Landfill Leachate Using Modified Coal Fly-Ash (CFA)

Per and Poly-fluoroalkyl Substances (PFAS) has been a major subject of research in environmental sector ever since it was found in the environment and blood serums at toxic levels. As landfills are the final disposal method for majority of the waste, PFAS concentration in landfill leachate have been found in the range of few µg/L to mg/L. Only few conventional treatments such as Activated Carbon, Reverse Osmosis, and Ion-Exchange has been proven effective in removing PFAS. However, these treatment methods are proving to be very expensive and generate secondary contamination that needs to be disposed-off or treated. Since the phase out of C8-PFAS compounds, more short chain PFAS compounds are detected in landfill leachate. Hence, an effective treatment strategy is needed to keep up with the rising concentration levels and variety of PFAS compounds. The purpose of this study was to develop a sustainable and cost-effective process using modified Coal Fly-Ash (CFA) that can treat both short chain and long chain PFAS compounds. Previous studies have shown application of CFA in removal of dye and metals from different types of wastewaters. In previous studies CFA was modified to enhance its surface properties, that can improve the adsorption of organic and anionic contaminants. In this study, thermo-chemical modification was used on CFA to remove organic matter and PFAS compounds. Preliminary results showed that, CFA can remove more than 90% UV absorbance, more than 80% TOC and approximately 40% of total PFAS compounds. The maximum adsorption capacity for total PFAS was found to be 84 ng PFAS per g CFA, out of which 70 ng was for short chain PFAS and 14 ng for long chain PFAS compounds. An effective removal of organic matter and PFAS compounds, show a promising application of CFA in leachate treatment. However, further research is needed to analyze the adsorption dynamics, kinetics, post-treatment disposal method, and any possible contamination when mixing CFA with landfill leachate

The 15-K neutron structure of saccharide-free concanavalin A

The positions of the ordered hydrogen isotopes of a protein and its bound solvent can be determined by using neutron crystallography. Furthermore, by collecting neutron data at cryo temperatures, the dynamic disorder within a protein crystal is reduced, which may lead to improved definition of the nuclear density. It has proved possible to cryo-cool very large Con A protein crystals (>1.5 mm(3)) suitable for high-resolution neutron and x-ray structure analysis. We can thereby report the neutron crystal structure of the saccharide-free form of Con A and its bound water, including 167 intact D(2)O molecules and 60 oxygen atoms at 15 K to 2.5-Å resolution, along with the 1.65-Å x-ray structure of an identical crystal at 100 K. Comparison with the 293-K neutron structure shows that the bound water molecules are better ordered and have lower average B factors than those at room temperature. Overall, twice as many bound waters (as D(2)O) are identified at 15 K than at 293 K. We note that alteration of bound water orientations occurs between 293 and 15 K; such changes, as illustrated here with this example, could be important more generally in protein crystal structure analysis and ligand design. Methodologically, this successful neutron cryo protein structure refinement opens up categories of neutron protein crystallography, including freeze-trapped structures and cryo to room temperature comparisons

What are we missing? False- negative cancers at multiparametric MR imaging of the prostate

Purpose: To characterize clinically important prostate cancers missed at multiparametric (MP) magnetic resonance (MR) imaging. Materials and Methods: The local institutional review board approved this HIPAAcompliant retrospective single-center study, which included 100 consecutive patients who had undergone MP MR imaging and subsequent radical prostatectomy. A genitourinary pathologist blinded to MP MR findings outlined prostate cancers on whole-mount pathology slices. Two readers correlated mapped lesions with reports of prospectively read MP MR images. Readers were blinded to histopathology results during prospective reading. At histopathologic examination, 80 clinically unimportant lesions (,5 mm; Gleason score, 3+3) were excluded. The same two readers, who were not blinded to histopathologic findings, retrospectively reviewed cancers missed at MP MR imaging and assigned a Prostate Imaging Reporting and Data System (PI-RADS) version 2 score to better understand false-negative lesion characteristics. Descriptive statistics were used to define patient characteristics, including age, prostate-specific antigen (PSA) level, PSA density, race, digital rectal examination results, and biopsy results before MR imaging. Student t test was used to determine any demographic differences between patients with false-negative MP MR imaging findings and those with correct prospective identification of all lesions. Results: Of the 162 lesions, 136 (84%) were correctly identified with MP MR imaging. Size of eight lesions was underestimated. Among the 26 (16%) lesions missed at MP MR imaging, Gleason score was 3+4 in 17 (65%), 4+3 in one (4%), 4+4 in seven (27%), and 4+5 in one (4%). Retrospective PI-RADS version 2 scores were assigned (PI-RADS 1, n = 8; PI-RADS 2, n = 7; PI-RADS 3, n = 6; and PI-RADS 4, n = 5). On a perpatient basis, MP MR imaging depicted clinically important prostate cancer in 99 of 100 patients. At least one clinically important tumor was missed in 26 (26%) patients, and lesion size was underestimated in eight (8%). Conclusion: Clinically important lesions can be missed or their size can be underestimated at MP MR imaging. Of missed lesions, 58% were not seen or were characterized as benign findings at second-look analysis. Recognition of the limitations of MP MR imaging is important, and new approaches to reduce this false-negative rate are needed

What Are We Missing? False-Negative Cancers at Multiparametric MR Imaging of the Prostate.

Purpose: To characterize clinically important prostate cancers missed at multiparametric (MP) magnetic resonance (MR) imaging. Materials and Methods: The local institutional review board approved this HIPAAcompliant retrospective single-center study, which included 100 consecutive patients who had undergone MP MR imaging and subsequent radical prostatectomy. A genitourinary pathologist blinded to MP MR findings outlined prostate cancers on whole-mount pathology slices. Two readers correlated mapped lesions with reports of prospectively read MP MR images. Readers were blinded to histopathology results during prospective reading. At histopathologic examination, 80 clinically unimportant lesions (,5 mm; Gleason score, 3+3) were excluded. The same two readers, who were not blinded to histopathologic findings, retrospectively reviewed cancers missed at MP MR imaging and assigned a Prostate Imaging Reporting and Data System (PI-RADS) version 2 score to better understand false-negative lesion characteristics. Descriptive statistics were used to define patient characteristics, including age, prostate-specific antigen (PSA) level, PSA density, race, digital rectal examination results, and biopsy results before MR imaging. Student t test was used to determine any demographic differences between patients with false-negative MP MR imaging findings and those with correct prospective identification of all lesions. Results: Of the 162 lesions, 136 (84%) were correctly identified with MP MR imaging. Size of eight lesions was underestimated. Among the 26 (16%) lesions missed at MP MR imaging, Gleason score was 3+4 in 17 (65%), 4+3 in one (4%), 4+4 in seven (27%), and 4+5 in one (4%). Retrospective PI-RADS version 2 scores were assigned (PI-RADS 1, n = 8; PI-RADS 2, n = 7; PI-RADS 3, n = 6; and PI-RADS 4, n = 5). On a perpatient basis, MP MR imaging depicted clinically important prostate cancer in 99 of 100 patients. At least one clinically important tumor was missed in 26 (26%) patients, and lesion size was underestimated in eight (8%). Conclusion: Clinically important lesions can be missed or their size can be underestimated at MP MR imaging. Of missed lesions, 58% were not seen or were characterized as benign findings at second-look analysis. Recognition of the limitations of MP MR imaging is important, and new approaches to reduce this false-negative rate are needed