Locating the Binding Sites of Pb(II) Ion with Human and Bovine Serum Albumins

Lead is a potent environmental toxin that has accumulated above its natural level as a result of human activity. Pb cation shows major affinity towards protein complexation and it has been used as modulator of protein-membrane interactions. We located the binding sites of Pb(II) with human serum (HSA) and bovine serum albumins (BSA) at physiological conditions, using constant protein concentration and various Pb contents. FTIR, UV-visible, CD, fluorescence and X-ray photoelectron spectroscopic (XPS) methods were used to analyse Pb binding sites, the binding constant and the effect of metal ion complexation on HSA and BSA stability and conformations. Structural analysis showed that Pb binds strongly to HSA and BSA via hydrophilic contacts with overall binding constants of KPb-HSA = 8.2 (±0.8)×104 M−1 and KPb-BSA = 7.5 (±0.7)×104 M−1. The number of bound Pb cation per protein is 0.7 per HSA and BSA complexes. XPS located the binding sites of Pb cation with protein N and O atoms. Pb complexation alters protein conformation by a major reduction of α-helix from 57% (free HSA) to 48% (metal-complex) and 63% (free BSA) to 52% (metal-complex) inducing a partial protein destabilization

FNA biopsy of secondary nonlymphomatous malignancies in salivary glands: A multi-institutional study of 184 cases.

Secondary malignancies of salivary glands (SMSGs) are among the most common malignant neoplasms to involve the salivary glands. Fine-needle aspiration biopsy (FNAB) of SMSG can present diagnostic challenges. The current report presents the largest such FNAB series to date. A search of the pathology database from 6 academic institutions identified 184 FNAB cases of nonlymphomatous SMSG. Of the 184 cases, 171 were of the parotid glands, and 13 were of the submandibular glands; 130 patients were men, and 54 were women, and the mean patient age at diagnosis was 68 years. Metastatic squamous cell carcinoma (SCC) from all sites (n = 87) and melanoma (n = 67) constituted the majority of SMSGs. Less frequent SMSGs were comprised of metastatic carcinomas from distant organs (n = 16), including sites in the breast, lung, kidney, thyroid, pancreatobiliary, prostate, and bladder. Other uncommon SMSGs, including nasopharyngeal carcinoma (n = 3), sarcoma (n = 4), other metastatic skin-derived carcinomas (n = 6), and metastatic chordoma (n = 1), also were observed. Ancillary tests were performed on 37 FNAB specimens (20.1%) to aid the evaluation. One hundred forty-seven specimens (79.9%) had a definitive diagnosis with accurate tumor subtyping, 21 (11.4%) had a definitive malignant diagnosis but without specifying subtype, 9 (4.9%) had an indeterminate diagnosis, and 7 (3.8%) had a false-negative diagnosis. SMSGs originate predominately from the head and neck and are more common in older men. Overall, the FNAB diagnosis of SMSG is accurate, but diagnostic challenges can be encountered, especially in SCC types of SMSG. Ancillary studies are needed for the definitive diagnosis of challenging cases. Cancer Cytopathol 2017;125:91-103. © 2016 American Cancer Society

Location and State of Pt in Platinized CdS/TiO2 Photocatalysts for Hydrogen Production from Water under Visible Light

CdS/TiO2 composite photocatalysts were platinized by different methods such as photodeposition (PD), wet impregnation (WI), and chemical reduction (CR), and studied for hydrogen production from water under visible light. All Pt species were in the metallic state, yet PD and WI photocatalysts contained electron-deficient Pt. In particular, Pt-Ti formation was identified in the WI catalyst, which contributed to electron deficiency of Pt. These two photocatalysts of electron-deficient Pt exhibited higher rates of hydrogen evolution due to favorable diffusion of photoelectrons from excited CdS toward the Pt. Between PD and WI photocatalysts, the PD catalyst showed a lower rate because part of the Pt in the catalyst resided on US, whereas all Pt species were located on TiO2 nanoparticles for WI and CR catalysts. The results indicate that the location as well as the electronic state of Pt is important for the high performance of platinized CdS/TiO2 photocatalysts in hydrogen production from waterclose777

Au Nanoparticles Supported Nanoporous ZnO Sphere for Enhanced Photocatalytic Activity Under UV-Light Irradiation

Monodispersed 200 nm-sized ZnO spheres (SPs) with porous structure emanating from 8 nm zinc oxide nanoparticles (NPs) composing the SPs were synthesized by dissolving zinc acetate dihydrate in diethylene glycol at 160 A degrees C. The prepared SPs were employed in fabricating the gold (Au) loaded ZnO (Au/ZnO SP) composite materials, exhibiting high photocatalytic activity in decomposing salicylic acid under UV-light irradiation. It is deduced that its high catalytic activity originates from the charge separation by transferring photoinduced electrons from the conduction band (CB) of ZnO to Au, since the CB level of ZnO (-0.5 V vs. NHE) is located more negative side than that of Au (+0.5 V vs. NHE). The evidence for the charge separation was provided by monitoring(.)OH radical with bare ZnO SPs and Au/ZnO SP produced in the solution which readily react with 1,4-terephthalic acid (TA) inducing 2-hydroxy terephthalic acid (TAOH) that shows unique fluorescence peak at 426 nm