Rolling ES cells down the Waddington landscape with Oct4 and Sox2

Embryonic stem cell (ESC) pluripotency is maintained by core transcriptional circuits whereby critical factors sustain their own expression while preventing the expression of genes required for differentiation. Thomson et al. (2011) now show that two core components of the pluripotency circuit, Oct4 and Sox2, are also critical for germ layer fate choice

Trithorax group proteins: switching genes on and keeping them active

Cellular memory is provided by two counteracting groups of chromatin proteins termed Trithorax group (TrxG) and Polycomb group (PcG) proteins. TrxG proteins activate transcription and are perhaps best known because of the involvement of the TrxG protein MLL in leukaemia. However, in terms of molecular analysis, they have lived in the shadow of their more famous counterparts, the PcG proteins. Recent advances have improved our understanding of TrxG protein function and demonstrated that the heterogeneous group of TrxG proteins is of critical importance in the epigenetic regulation of the cell cycle, senescence, DNA damage and stem cell biology

Prediction of Local Structural Stabilities of Proteins from Their Amino Acid Sequences

Hydrogen exchange experiments provide detailed information about the local stability and the solvent accessibility of different regions of the structures of folded proteins, protein complexes, and amyloid fibrils. We introduce an approach to predict protection factors from hydrogen exchange in proteins based on the knowledge of their amino acid sequences without the inclusion of any additional structural information. These results suggest that the propensity of different regions of the structures of globular proteins to undergo local unfolding events can be predicted from their amino acid sequences with an accuracy of 80% or better. © 2007 Elsevier Ltd. All rights reserved

Laser arytenoidectomy in children with bilateral vocal fold immobility

Bilateral vocal fold immobility in children is a challenging problem because a balance between good airway and voice quality has to be achieved. Surgery to improve the airway is often postponed or avoided because of fear of losing the voice. In this study our results of laser arytenoidectomy in children are described. This was a retrospective case notes review at a tertiary level paediatric ENT department. The six patients in this case series ranged from nine to 16 years old at the time of laser arytenoidectomy. Post-operative airway and voice quality were assessed. All children in the series had an adequate post-operative airway. Four of these patients had tracheostomies pre-operatively and achieved decannulation. All six patients rated their post-operative voice as better than pre-operatively. This is principally due to increased loudness associated with increased airflow through the larynx, particularly after tracheostomy decannulation. It is recommended that special care should be taken not to disturb the anterior two thirds of the vocal fold during the surgery in order to achieve a good post-operative voice outcome

Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency

We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) makes them suitable for photothermal therapy as demonstrated by tumor cell annihilation upon laser irradiation. The otherwise harmless nature of these NCs in dark conditions was confirmed by in vitro toxicity tests on two different cell lines. The presence of the deep Fe levels constituting the IB is the origin of such enhanced PTE, which can be used to design other high performing NC photothermal agents.Comment: 12 pages, Chemistry of Materials, 31-May-201

What are we going to do about a problem like polymer chemistry? Develop new methods of delivery to improve understanding of a demanding interdisciplinary topic

Following collaboration between two chemistry lecturers and an academic developer an attempt was made to enhance the learning of students within a chemistry module through the adaptation of the delivery of content material. This paper reports a piece of practitioner led research which considered how effective the approach developed was upon the level of student understanding and the process through which this occurred. The module delivery was altered from an emphasis on the transmission of knowledge through a traditional lecture format, to rotating small group problem based sessions and the use of concept maps. Student feedback and higher grades achieved appear to demonstrate it was effective

Organism complexity anti-correlates with proteomic β-aggregation propensity

We introduce a novel approach to estimate differences in the β-aggregation potential of eukaryotic proteomes. The approach is based on a statistical analysis of the β-aggregation propensity of polypeptide segments, which is calculated by an equation derived from first principles using the physicochemical properties of the natural amino acids. Our analysis reveals a significant decreasing trend of the overall β-aggregation tendency with increasing organism complexity and longevity. A comparison with randomized proteomes shows that natural proteomes have a higher degree of polarization in both low and high β-aggregation prone sequences. The former originates from the requirement of intrinsically disordered proteins, whereas the latter originates from the necessity of proteins with a stable folded structure. Published by Cold Spring Harbor Laboratory Press. Copyright © 2005 The Protein Society

Search for the radion using the ATLAS detector

The possibility of observing the radion using the ATLAS detector at LHC is investigated. Studies on searches for the Standard Model Higgs with the ATLAS detector are re-interpreted to obtain limits on radion decay to gamma-gamma and ZZ(*). The observability of radion decays into Higgs pairs, which subsequently decay into gamma-gamma+b-bbar or tau-tau+b-bbar is then estimate