Encapsulation of cadmium selenide nanocrystals in biocompatible nanotubes: DFT calculations, X-ray diffraction investigations, and confocal fluorescence imaging

The encapsulation of CdSe nanocrystals within single-walled carbon nanotube (SWNT) cavities of varying dimensions at elevated temperatures under strictly air-tight conditions is described for the first time. The structures of CdSe nanocrystals under confinement inside SWNTs was established in a comprehensive study, combining both experimental and DFT theoretical investigations. The calculated binding energies show that all considered polymorphs [(3:3), (4:4), and (4:2)] may be obtained experimentally. The most thermodynamically stable structure (3:3) is directly compared to the experimentally observed CdSe structures inside carbon nanotubes. The gas-phase DFT-calculated energy difference between "free" 3:3 and 4:2 structures (whereby 3:3 models a novel tubular structure in which both Cd and Se form three coordination, as observed experimentally for HgTe inside SWNT, and 4:2 is a motif derived from the hexagonal CuI bulk structure in which both Cd and Se form 4 or 2 coordination) is surprisingly small, only 0.06eV per formula unit. X-ray powder diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray analyses led to the full characterization of the SWNTs filled with the CdSe nanocrystals, shedding light on the composition, structure, and electronic interactions of the new nanohybrid materials on an atomic level. A new emerging hybrid nanomaterial, simultaneously filled and beta-d-glucan coated, was obtained by using pristine nanotubes and bulk CdSe powder as starting materials. This displayed fluorescence in water dispersions and unexpected biocompatibility was found to be mediated by beta-d-glucan (a biopolymer extracted from barley) with respect to that of the individual inorganic m aterial components. For the first time, such supramolecular nanostructures are investigated by life-science techniques applied to functional nanomaterial characterization, opening the door for future nano-biotechnological applications

Moonlighting Proteins Hal3 and Vhs3 Form a Heteromeric PPCDC with Ykl088w in Yeast CoA Biosynthesis

Premi a l'excel·lència investigadora. 2010Unlike most other organisms, the essential five-step Coenzyme A biosynthetic pathway has not been fully resolved in yeast. Specifically, the gene(s) encoding the phosphopantothenoylcysteine decarboxylase (PPCDC) activity still remains unidentified. Sequence homology analyses suggest three candidates, namely Ykl088w, Hal3 and Vhs3, as putative PPCDC enzymes in Saccharomyces cerevisiae. Interestingly, Hal3 and Vhs3 have been characterized as negative regulatory subunits of the Ppz1 protein phosphatase. Here we show that YKL088w does not encode a third Ppz1 regulatory subunit, and that the essential roles of Ykl088w and the Hal3/Vhs3 pair are complementary, cannot be interchanged and can be attributed to PPCDC-related functions. We demonstrate that while known eukaryotic PPCDCs are homotrimers, the active yeast enzyme is a heterotrimer which consists of Ykl088w and Hal3/Vhs3 monomers that separately provides two essential catalytic residues. Our results unveil Hal3/Vhs3 as moonlighting proteins, involved in both CoA biosynthesis and protein phosphatase regulation

Effects of MDM2, MDM4 and TP53 Codon 72 Polymorphisms on Cancer Risk in a Cohort Study of Carriers of TP53 Germline Mutations

Previous studies have shown that MDM2 SNP309 and p53 codon 72 have modifier effects on germline P53 mutations, but those studies relied on case-only studies with small sample sizes. The impact of MDM4 polymorphism on tumor onset in germline mutation carriers has not previously been studied.We analyzed 213 p53 germline mutation carriers including 168(78.9%) affected with cancer and 174 who had genotypic data. We analyzed time to first cancer using Kaplan-Meier and Cox proportional hazards methods, comparing risks according to polymorphism genotypes. For MDM2 SNP309, a significant difference of 9.0 years in the average age of cancer diagnosis was observed between GG/GT and TT carriers (18.6 versus 27.6 years, P = 0.0087). The hazards ratio was 1.58 (P = 0.03) comparing risks among individuals with GG/GT to risk among TT, but this effect was only significant in females (HR = 1.60, P = 0.02). Compared to other genotypes, P53 codon 72 PP homozygotes had a 2.24 times (P = 0.03) higher rate for time to develop cancer. We observed a multiplicative joint effect of MDM2 and p53 codon72 polymorphism on risk. The MDM4 polymorphism had no significant effects.Our results suggest that the MDM2 SNP309 G allele is associated with cancer risk in p53 germline mutation carriers and accelerates time to cancer onset with a pronounced effect in females. A multiplicative joint effect exists between the MDM2 SNP309 G allele and the p53 codon 72 G allele in the risk of cancer development. Our results further define cancer risk in carriers of germline p53 mutations

Inmunohistochemical Profile of Solid Cell Nest of Thyroid Gland

It is widely held that solid cell nests (SCN) of the thyroid are ultimobranchial body remnants. SCNs are composed of main cells and C cells. It has been suggested that main cells might be pluripotent cells contributing to the histogenesis of C cells and follicular cells, as well as to the formation of certain thyroid tumors. The present study sought to analyze the immunohistochemical profile of SCN and to investigate the potential stem cell role of SCN main cells. Tissue sections from ten cases of nodular hyperplasia (non-tumor goiter) with SCNs were retrieved from the files of the Hospital Infanta Luisa (Seville, Spain). Parathormone (PTH), calcitonin (CT), thyroglobulin (TG), thyroid transcription factor (TTF-1), galectin 3 (GAL3), cytokeratin 19 (CK 19), p63, bcl-2, OCT4, and SALL4 expression were evaluated by immunohistochemistry. Patient clinical data were collected, and tissue sections were stained with hematoxylin–eosin for histological examination. Most cells stained negative for PTH, CT, TG, and TTF-1. Some cells staining positive for TTF-1 and CT required discussion. However, bcl-2, p63, GAL3, and CK 19 protein expression was detected in main cells. OCT4 protein expression was detected in only two cases, and SALL4 expression in none. Positive staining for bcl-2 and p63, and negative staining for PTH, CT, and TG in SCN main cells are both consistent with the widely accepted minimalist definition of stem cells, thus supporting the hypothesis that they may play a stem cell role in the thyroid gland, although further research will be required into stem cell markers. Furthermore, p63 and GAL-3 staining provides a much more sensitive means of detecting SCNs than staining for carcinoembryonic antigen, calcitonin, or other markers; this may help to distinguish SCNs from their mimics

Rushlight: Fall 1982

Wheaton College (Norton, MA) student literary magazine.Glass BanglesTenement at NightCatching Beads at Mardi Gras (for K.C)woodcutPetty Dreads: 6 Poems in Five Lines: for FensonSI to NY and Back AgainUntitledParis, A Rainy DayRunner's AccidentMorning GlorywoodcutWell...I triedAT NINETEENEVEIron GatesMan in Hat and Cape--(for Brian)At the BeachLittle Jack's DinnerphotoBisectionELEGY FOR A PUBLIC DEATH, for John LennonphotountitledGHAZALLetter to a Negelctful Love: things to do with a heartphotoThe PoetVANISHING COUNTRIESphotoYou Caught Me Off GardenIllustrationPersonal RhythmbriadAPERTUNAPhoto50/60Carpe CrasphotoThree WomenNOAH"Winter Into Spring"THE PROJECTPhotoPoof! A Story About Spontaeneous Combustio