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Fast reduction of Cr(VI) from aqueous solutions using alumina
Fabiola Glorias-Garcia,Jose´ Miguel Arriaga-Merced,Gabriela Roa-Morales,Vı´ctor Varela-Guerrero,Carlos Eduardo Barrera-Dı´az,Bryan Bilyeu 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4
Hexavalent chromium is challenging to remove from industrial wastewater due the solubility and anionic nature of the chromates. Cr(VI) is typically removed by reduction to Cr(III), then precipitation or adsorption, which requires multiple steps and bulk reagents and generates sludge. In this project, we have evaluated a sintered alumina disk as a single step sorbent for Cr(VI). The disk was porous enough that 20 mL samples passed through in about 3 s using light suction. A single pass through the disk only reduced the [Cr(VI)] by 10–20%, but by passing the solution through the disk five times up to 80% was removed in samples up to 130 mg/L and up to around 50% for much higher concentrations. The five passes through the filter disk took less than a minute. On each pass through the disk the characteristic chromate UV–vis absorbance decreased, the Cr(VI) concentration (by the diphenylcarbazide method) decreased, and the pH rose slightly. The XRD pattern showed no change in the crystal structure of the alumina, but the SEM/EDS identified chromium on the surface. In addition to confirming chromium on the surface of the alumina, the XPS spectra showed a change in the binding energy of the aluminum, which is consistent with complexation. The system was fast and effective (in series), so should be applicable to industrial wastewater treatment.
Gazi, M.,Sultana, T.,Min, G.S.,Park, Y.C.,Garcia-Varela, M.,Nadler, S.A.,Park, J.K. Elsevier 2012 Parasitology international Vol.61 No.2
In the present study, we determined the complete mitochondrial genome sequence of Oncicola luehei (14,281bp), the first archiacanthocephalan representative and the second complete sequence from the phylum Acanthocephala. The complete genome contains 36 genes including 12 protein coding genes, 22 transfer RNA (tRNA) genes and 2 ribosomal RNA genes (rrnL and rrnS) as reported for other syndermatan species. All genes are encoded on the same strand. The overall nucleotide composition of O. luehei mtDNA is 37.7% T, 29.6% G, 22.5% A, and 10.2% C. The overall A+T content (60.2%) is much lower, compared to other syndermatan species reported so far, due to the high frequency (18.3%) of valine encoded by GTN in its protein-coding genes. Results from phylogenetic analyses of amino acid sequences for 10 protein-coding genes from 41 representatives of major metazoan groups including O. luehei supported monophyly of the phylum Acanthocephala and of the clade Syndermata (Acanthocephala+Rotifera), and the paraphyly of the clade Eurotatoria (classes Bdelloidea+Monogononta from phylum Rotifera). Considering the position of the acanthocephalan species within Syndermata, it is inferred that obligatory parasitism characteristic of acanthocephalans was acquired after the common ancestor of acanthocephalans diverged from its sister group, Bdelloidea. Additional comparison of complete mtDNA sequences from unsampled acanthocephalan lineages, especially classes Polyacanthocephala and Eoacanthocephala, is required to test if mtDNA provides reliable information for the evolutionary relationships and pattern of life history diversification found in the syndermatan groups.
A rare case of choledochal cyst with pancreas divisum
Adrian Ransom-Rodriguez,Ruben Blachman-Braun,Emilio Sanchez-Garcia Ramos,Jesus Varela-Prieto,Erick Rosas-Lezama,Miguel Angel Mercado 한국간담췌외과학회 2017 Annals of hepato-biliary-pancreatic surgery Vol.21 No.1
Choledochal cysts are rare congenital malformations of the bile duct characterized by dilatations of the intrahepatic and/or extrahepatic portion of the biliary tree, they are associated to an anomalous arrangement of the pancreaticobiliary duct. Pancreas divisum results from a fusion failure of the pancreatic buds. The coexistence of pancreas divisum and choledochal cyst in adults has been reported in less than 10 well documented cases. This article presents a case of a 42-year-old Peruvian man with intermittent episodes of abdominal pain, initially diagnosed with choledocholithiasis, who underwent open cholecystectomy. During surgery, a diagnosis of choledochal cyst and pancreas divisum was made, and therefore a hepaticoduodenostomy was performed. The patient was referred to our hospital due to persistence of abdominal pain. After admission, a papillectomy was achieved without further complications. A cyst resection and dismantling of hepaticoduodenostomy with Roux-en-Y was performed 8 years later. During the subsequent 18-month follow-up, the patient remains asymptomatic.