Proteins conjugation with ZnO sol–gel nanopowders

The conjugation between probe biomolecules and inorganic nanoparticles has been studied. Three different and biologically relevant proteins, bovine serum albumin (BSA), lysozyme (LSZ) and Ribonuclease A (RNAseA), have been selected as model systems because of their difference in size and isoelectric point. Zinc oxide nanoparticles, synthesized via sol–gel, have been thoroughly characterized by X-ray Photoelectron Spectroscopy, Scanning Electron Microscopy and X-ray Diffraction, and subsequently used as platforms for immobilization of the biomolecules. The interaction of the three proteins with the ZnO surface was performed in phosphate buffer solutions at pH 7.2 in order to mimic physiological fluids and was investigated through fluorescence experiments. The obtained results indicate that conjugation of BSA, LZS and RNAseA on the oxide nanoparticles was mostly dictated by the overall charge of the different proteins. Electrostatic bonds dominate the formation of the protein/ZnO conjugates, whereas the size of the proteins seems to play a negligible role under the adopted experimental conditions.     

Total synthesis of chloptosin: a dimeric cyclohexapeptide

Here we describe in full our investigations into the synthesis of the dimeric cyclohexapeptide chloptosin in 17 linear steps. Particularly, this work features an organocatalytic tandem process for the synthesis of the embedded piperazic acids, in which a differentially protected azodicarboxylate is used together with pyrrolidinyl tetrazole as the catalyst. The central biaryl bond is being formed by Stille coupling of two sterically demanding ortho-chloropyrroloindole fragments. The inherent flexibility of the synthetic strategy proved beneficial as the route could be adjusted smoothly during the progression of the synthesis programme.     

Seeing the light: luminescent reporter gene assays

The luminescent reporter gene assay (LRGA) is arguably the most prominent type of reporter gene assay used in biomolecular and pharmaceutical development laboratories. Part of this popularity is due to the high signal associated with luciferases, the foundation of this technology. This feature makes them ideally suited for high throughput screening applications where potentially millions of chemical compounds can be analyzed in a given assay. Recent technical advancements that enhance signal stability of the luciferases along with development and commercialization of multiple forms of luciferases, their respective substrates, and improvements in expression vectors for reporter gene assay (RGA) applications have broadened their use. While the practical challenges related to the application of luminescent technology in a laboratory setting have been overcome, there remains much to do in laying a systematic approach towards the construction of RGAs, which are essential to the elucidation of the basic biology for genes of interest. This mini-review aims at giving a birds-eye view of the available luciferases, substrates and other luminescent technologies available and provides a general blueprint as well as practical considerations for constructing and interfacing RGAs with chemical biology and functional genomics for the elucidation of fundamental biological questions and for biomedical research.     

Divisorial prime ideals of int(D) when D is a krull-type domain

Let Dbe a domain with quotient field K. The ring of integer-valued polynomials over Dis Int (D):={f? K[X];f(4D) ? D}.We describe the divisorial prime ideals of Int(D) when Dis a domain of Krull-type and, in particular, when Dis also a d-ring.     

Combined XRF‐SEM analysis of varnished pottery: the case of Syracuse and Adrano (Sicily) archaelogical finds

Micro‐destructive and non‐destructive X‐Ray fluorescence techniques and scanning electron microscopy coupled with energy‐dispersive spectrometry have been applied for the analysis of ten samples of Hellenistic black‐varnished pottery, coming from archaeological excavations in Syracuse and Adrano (South Italy, Sicily). Micro‐morphological and compositional investigations, together with statistical data processing, have shown several differences among the varnishes of the specimen found in the two sites. In particular, Syracuse varnishes are characterised by a more homogeneous composition and well‐defined raw materials, whereas Adrano samples show a higher variability, probably linked to the use of different raw materials and the poorer quality of the varnish as well. The obtained results attest that, as Syracuse black pottery is concerned, the production technique is at an advanced level, whereas Adrano manufacture seems to be less specialised. Copyright © 2012 John Wiley & Sons, Ltd.     

Analytical Instrumental Techniques to Study Archaeological Wood Degradation

Abstract

Historically, a very large variety of everyday artifacts were made of wood, which makes them representative of their historical period or social context and valuable for archaeologists and historians. In order to preserve degraded wood and to develop and apply suitable conservation treatments, chemical and physical characterization of archaeological wood is needed. This review provides the reader with a survey on state-of-the-art of instrumental analytical tools available to understand the morphology and the chemical composition of archaeological wood. The focus is on microscopic and spectroscopic techniques such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman, nuclear magnetic resonance (NMR) and analytical techniques based on pyrolysis, such as direct exposure–mass spectrometry (DE-MS), pyrolysis–mass spectrometry (Py-MS), pyrolysis–gas chromtography–mass spectrometry (Py-GC/MS), with emphasis on their respective potentialities and limitations. The advantages of techniques based on synchrotron radiation are also discussed. In addition, the applicability of each examined technique is illustrated and discussed through specific examples from the literature.     

Reproducibility and biases in high field brain diffusion MRI: An evaluation of acquisition and analysis variables

Diffusion tensor imaging (DTI) of in-vivo human brain provides insights into white matter anatomical connectivity, but little is known about measurement difference biases and reliability of data obtained with last generation high field scanners (> 3 T) as function of MRI acquisition and analyses variables. Here we assess the impact of acquisition (voxel size: 1.8 × 1.8 × 1.8, 2 × 2 × 2 and 2.5 × 2.5 × 2.5 mm³, b-value: 700, 1000 and 1300 s/mm²) and analysis variables (within-session averaging and co-registration methods) on biases and test-retest reproducibility of some common tensor derived quantities like fractional anisotropy (FA), mean diffusivity (MD), axial and radial diffusivity in a group of healthy subjects at 4 T in three regions: arcuate fasciculus, corpus callosum and cingulum. Averaging effects are also evaluated on a full-brain voxel based approach. The main results are: i) group FA and MD reproducibility errors across scan sessions are on average double of those found in within-session repetitions (≈ 1.3 %), regardless of acquisition protocol and region; ii) within-session averaging of two DTI acquisitions does not improve reproducibility of any of the quantities across sessions at the group level, regardless of acquisition protocol; iii) increasing voxel size biased MD, axial and radial diffusivities to higher values and FA to lower values; iv) increasing b-value biased all quantities to lower values, axial diffusivity showing the strongest effects; v) the two co-registration methods evaluated gave similar bias and reproducibility results. Altogether these results show that reproducibility of FA and MD is comparable to that found at lower fields, not significantly dependent on pre-processing and acquisition protocol manipulations, but that the specific choice of acquisition parameters can significantly bias the group measures of FA, MD, axial and radial diffusivities.     

Partial Regularity for Stationary Solutions to Liouville-Type Equation in Dimension 3

In dimension n = 3, we prove that the singular set of any stationary solution to the Liouville equation ? Δ u = e ^u , which belongs to W ^1,2, has Hausdorff dimension at most 1.     

Advances in bio-imaging: a survey from WWMR 2010

The paper deals with a survey on major advances in the field of bio-imaging presented at the WWMR2010 Conference, held in Florence (Italy) from 4th to 9th July 2010. The selected contributions have been organized into the following headings: Hyperpolarization, Acquisition Methods and Molecular Imaging applications. Overall, the Conference has witnessed an outstanding progress in either methods and applications that further stresses the key-role of MRI in many fields of biomedicine.     

Synthesis by MW-assisted direct arylation,side-arms driven self-assembly and functional properties of 9,10-dithienylanthracene orthogonal materials

We report a new class of multifunctional 9,10-dithienylanthracene-based materials having an anthracene π-core functionalized at the 9,10 positions with thienyl side-arms of different size and type of substitution. MW-assisted double direct arylation reaction is employed for the first time to synthesize the target molecules in one-step, organometallic free conditions, in only 5 min and yields up to 80% rather than by a multi-step Stille coupling taken as conventional reference approach. DFT calculations reveal a molecular conformation characterized by the thienyl rings orthogonal to the anthracene core. Nevertheless, despite the non-coplanar structure, all compounds exhibited highly crystalline cast films emitting blue light, with an extraordinary variability in morphology and hole mobility up to 8×10⁻³ cm² V⁻¹ s⁻¹.