Reductive degradation of perfluorinated compounds in water using Mg-aminoclay coated nanoscale zero valent iron

Arvaniti, Olga S.,Hwang, Yuhoon,Andersen, Henrik R.,Stasinakis, Athanasios S.,Thomaidis, Nikolaos S.,Aloupi, Maria Elsevier 2015 Chemical engineering journal Vol.262 No.-

<P><B>Abstract</B></P> <P>Perfluorinated compounds (PFCs) are extremely persistent micropollutants that are detected worldwide. We studied the removal of PFCs (perfluorooctanoic acid; PFOA, perfluorononanoic acid; PFNA, perfluorodecanoic acid; PFDA and perfluorooctane sulfonate; PFOS) from water by different types of nanoscale zero-valent iron (nZVI). Batch experiments showed that an iron dose of 1gL<SUP>−1</SUP> in the form of Mg-aminoclay (MgAC) coated nZVI, at an initial pH of 3.0 effectively removed 38–96% of individual PFCs. An increasing order of removal efficiency was observed of PFOA<PFNA<PFOS≈PFDA. Compared to this, PFCs removal was less than 27% using a commercial air stabilized nZVI or freshly synthesized uncoated nZVI, under the same experimental conditions. The effectiveness of PFCs removal by MgAC coated nZVI was further investigated at various initial pH, nZVI dosage, temperature and age of the nZVI. A maximum removal was observed for all PFCs with high nZVI concentration, freshly synthesized nZVI, low pH and low temperature. A mass balance experiment with PFOS in a higher concentration of nZVI revealed that the removal was due to both sorption and degradation. Fluoride production partially matched the observed degradation, while no organic byproducts were detected using LC–QTOF–MS.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Different nanosized zero valent iron (nZVI) types were tested for PFCs degradation. </LI> <LI> Only nZVI coated with a cationic surface modifier removed PFCs effectively. </LI> <LI> The order of PFCs degradability was PFOA<PFNA<PFOS≈PFDA. </LI> <LI> Low pH and temperature favored degradation of PFCs by surface modified nZVI. </LI> <LI> Fluoride formation confirmed PFCs degradation while partial sorption was observed. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Concentration inequalities for Kernel density estimators under uniform mixing

Arvanitis Stelios 한국통계학회 2023 Journal of the Korean Statistical Society Vol.52 No.2

We derive non-asymptotic concentration inequalities for the uniform deviation between a multivariate density function and its non-parametric kernel density estimator in stationary and uniform mixing time series framework. We derive analogous inequalities for their (first) Wasserstein distance, as well as for the deviations between integrals of bounded functions w.r.t. them. They can be used for the construction of confidence regions, the estimation of the finite sample probabilities of decision errors, etc. We employ the concentration results to the derivation of statistical guarantees and oracle inequalities in regularized prediction problems with Lipschitz and strongly convex costs.

Isolation and Identification Rhizosphere and Phyllosphere Microfungi of Keben (barringtonia Asiatica Kurz.) in Pancur Costal Forest Alas Purwo National Park East Java

Arvan Solatan Rescho 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Incidental Non-Cardiac Findings of a Coronary Angiography with a 128-Slice Multi-Detector CT Scanner: Should We Only Concentrate on the Heart?

Olga Lazoura,Katerina Vassiou,Theodora Kanavou,Marianna Vlychou,Dimitrios L. Arvanitis,Ioannis V. Fezoulidis 대한영상의학회 2010 Korean Journal of Radiology Vol.11 No.1

Objective: To evaluate the spectrum, prevalence, and significance of incidental non-cardiac findings (INCF) in patients referred for a non-invasive coronary angiography using a 128-slice multi-detector CT (MDCT). Materials and Methods: The study subjects included 1,044 patients; 774 males (mean age, 59.9 years) and 270 females (mean age, 63 years), referred for a coronary CT angiography on a 128-slice MDCT scanner. The scans were acquired from the level of the carina to just below the diaphragm. To evaluate INCFs, images were reconstructed with a large field of view (> 300 mm) covering the entire thorax. Images were reviewed in the axial, coronal, and sagittal planes, using the mediastinal, lung, and bone windows. The INCFs were classified as severe, indeterminate, and mild, based on their clinical importance, and as thoracic or abdominal based on their locations. Results: Incidental non-cardiac findings were detected in 56% of patients (588 of 1,044), including 435 males (mean age, 65.6 years) and 153 females (mean age, 67.9 years). A total of 729 INCFs were observed: 459 (63%) mild (58% thoracic, 43% abdominal), 96 (13%) indeterminate (95% thoracic, 5% abdominal), and 174 (24%) severe (87% thoracic, 13% abdominal). The prevalence of severe INCFs was 15%. Two severe INCFs were histologically verified as lung cancers. Conclusion: The 128-slice MDCT coronary angiography, in addition to cardiac imaging, can provide important information on the pathology of the chest and upper abdomen. The presence of severe INCFs is not rare, especially in the thorax. Therefore, all organs in the scan should be thoroughly evaluated in daily clinical practice. Objective: To evaluate the spectrum, prevalence, and significance of incidental non-cardiac findings (INCF) in patients referred for a non-invasive coronary angiography using a 128-slice multi-detector CT (MDCT). Materials and Methods: The study subjects included 1,044 patients; 774 males (mean age, 59.9 years) and 270 females (mean age, 63 years), referred for a coronary CT angiography on a 128-slice MDCT scanner. The scans were acquired from the level of the carina to just below the diaphragm. To evaluate INCFs, images were reconstructed with a large field of view (> 300 mm) covering the entire thorax. Images were reviewed in the axial, coronal, and sagittal planes, using the mediastinal, lung, and bone windows. The INCFs were classified as severe, indeterminate, and mild, based on their clinical importance, and as thoracic or abdominal based on their locations. Results: Incidental non-cardiac findings were detected in 56% of patients (588 of 1,044), including 435 males (mean age, 65.6 years) and 153 females (mean age, 67.9 years). A total of 729 INCFs were observed: 459 (63%) mild (58% thoracic, 43% abdominal), 96 (13%) indeterminate (95% thoracic, 5% abdominal), and 174 (24%) severe (87% thoracic, 13% abdominal). The prevalence of severe INCFs was 15%. Two severe INCFs were histologically verified as lung cancers. Conclusion: The 128-slice MDCT coronary angiography, in addition to cardiac imaging, can provide important information on the pathology of the chest and upper abdomen. The presence of severe INCFs is not rare, especially in the thorax. Therefore, all organs in the scan should be thoroughly evaluated in daily clinical practice.

Detection of O-Linked-N-Acetylglucosamine Modification and Its Associated Enzymes in Human Degenerated Intervertebral Discs

Georgios Nikolaou,Aristeidis H. Zibis,Apostolos H. Fyllos,Antonios Katsioulis,Sotirios Sotiriou,Anastasios Kotrotsios,Markos Sgantzos,Aikaterini Vassiou,Dimitrios L. Arvanitis 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.6

Study Design: Human herniated discs were obtained from discectomy specimens for the immunohistochemical detection of OGlcNAc and O-GlcNAcase (OGA)/O-GlcNAc transferase (OGT). Purpose: This study aimed to quantify the extent of O-GlcNAcylation and its associated enzymes (OGT/OGA) in human degenerated intervertebral discs. Overview of Literature: The O-GlcNAcylation of nuclear, cytoplasmic, and mitochondrial proteins as well as the effects of such post-translational modifications are currently the focus of extensive research. O-GlcNAcylation is believed to contribute to the etiology of chronic illnesses by acting as a nutrient and stress sensor in the cellular environment. Mature intervertebral disc cells are chondrocyte-like cells, and O-GlcNAc has been shown to promote chondrocyte apoptosis in vitro . We believe that O-GlcNAcylation is a key regulator of disc degeneration. Methods: Fifty-six specimens were fixed for 24 hours in a 10% solution of neutral-buffered formaldehyde, dehydrated, and embedded in paraffin. Tissue slices (4-μm-thick) were used for hematoxylin-eosin staining and immunohistochemistry. Results: We found that O-GlcNAcylation of cytoplasmic proteins was less than that of nuclear proteins in both single cells and cell clusters. Cytoplasmic O-GlcNAcylation occurs subsequent to nuclear O-GlcNAcylation and is directly proportional to disc degeneration. OGT and O-GlcNAc expression levels were identical in all specimens examined. Conclusions: O-GlcNAc and OGA/OGT expression is shown to correlate for the first time with intervertebral disc cell degeneration. Increasing disc degeneration is associated with increasing O-GlcNAcylation in both nuclear and cytoplasmic proteins in human disc cells.

Autophagy is a major regulator of beta cell insulin homeostasis

Riahi, Yael,Wikstrom, Jakob D.,Bachar-Wikstrom, Etty,Polin, Nava,Zucker, Hava,Lee, Myung-Shik,Quan, Wenying,Haataja, Leena,Liu, Ming,Arvan, Peter,Cerasi, Erol,Leibowitz, Gil Springer-Verlag 2016 Diabetologia Vol.59 No.7

<P>Aims/hypothesis We studied the role of protein degradation pathways in the regulation of insulin production and secretion and hypothesised that autophagy regulates proinsulin degradation, thereby modulating beta cell function. Methods Proinsulin localisation in autophagosomes was demonstrated by confocal and electron microscopy. Autophagy was inhibited by knockdown of autophagy-related (ATG) proteins and using the H+-ATPase inhibitor bafilomycin-A1. Proinsulin and insulin content and secretion were assessed in static incubations by ELISA and RIA. Results Confocal and electron microscopy showed proinsulin localised in autophagosomes and lysosomes. Beta-Atg7(-/-) mice had proinsulin-containing sequestosome 1 (p62 [also known as SQSTM1])(+) aggregates in beta cells, indicating proinsulin is regulated by autophagy in vivo. Short-term bafilomycin-A1 treatment and ATG5/7 knockdown increased steady-state proinsulin and hormone precursor chromogranin A content. ATG5/7 knockdown also increased glucose- and non-fuel-stimulated insulin secretion. Finally, mutated forms of proinsulin that are irreparably misfolded and trapped in the endoplasmic reticulum are more resistant to degradation by autophagy. Conclusions/interpretation In the beta cell, transport-competent secretory peptide precursors, including proinsulin, are regulated by autophagy, whereas efficient clearance of transport-incompetent mutated forms of proinsulin by alternative degradative pathways may be necessary to avoid beta cell proteotoxicity. Reduction of autophagic degradation of proinsulin increases its residency in the secretory pathway, followed by enhanced secretion in response to stimuli.</P>