New hybrid materials with porphyrin-ferrocene and porphyrin-pyrene covalently linked to single-walled carbon nanotubes.

Novel porphyrin derivatives bearing additional pyrene or ferrocene units as light harvesting antenna systems were synthesized and fully characterized. Following a covalent functionalization approach for single-walled carbon nanotubes (SWCNTs), stable SWCNT suspensions in common organic solvents 10 were produced. Subsequently, the resulting porphyrin-pyrene and porphyrin-ferrocene dyads were incorporated onto the nanotubes' backbone yielding donor-donor-acceptor hybrids. The resulting hybrid materials were soluble in common organic solvents and were characterized using micro-Raman, ATR-IR, UV-Vis and photoluminescence spectroscopy, transmission electron microscopy, thermogravimetric analysis and εlectrochemistry. Photoluminescence quenching of the porphyrin emission in both hybrid 15 materials was detected thus suggesting the potentiality of these materials in photoelectrochemical cells

The Search for Stock Market Bubbles: An Examination of the NYSE Index

Many have put forth reasons why the stock market has climbed to new and unprecedented heights. Two reasons are examined: (1) investors are expecting prices to increase and are bidding up price irrationally; (2) investors have moved to a long-term strategy and are requiring a lower risk premium. For the latter reason, the rise in stock prices is due to a change in the fundamentals, and for the former reason the rise represents the classical bubble. The evidence indicates that risk preferences have changed while price momentum does not appear during bubble periods

Functionalized Poly(3-hexylthiophene)s via Lithium–Bromine Exchange

Poly(3-hexylthiophene) (P3HT) is one of the most extensively investigated conjugated polymers and has been employed as the active material in many devices including field-effect transistors, organic photovoltaics and sensors. As a result, methods to further tune the properties of P3HT are desirable for specific applications. Herein, we report a facile postpolymerization modification strategy to functionalize the 4-position of commercially available P3HT in two simple steps–bromination of the 4-position of P3HT (Br–P3HT) followed by lithium−bromine exchange and quenching with an electrophile. We achieved near quantitative lithium–bromine exchange with Br–P3HT, which requires over 100 thienyl lithiates to be present on a single polymer chain. The lithiated-P3HT is readily combined with functional electrophiles, resulting in P3HT derivatives with ketones, secondary alcohols, trimethylsilyl (TMS) group, fluorine, or an azide at the 4-position. We demonstrated that the azide-modified P3HT could undergo Cu-catalyzed or Cu-free click chemistry, significantly expanding the complexity of the structures that can be appended to P3HT using this method.National Science Foundation (U.S.) (ECCS-0939514

Zinc Phthalocyanine−Graphene Hybrid Material for Energy Conversion: Synthesis, Characterization, Photophysics and Photoelectrochemical Cell Preparation

Graphene exfoliation upon tip sonication in o-­‐DCB was accomplished. Then, covalent grafting of (2-­‐ aminoethoxy)(tri-­‐tert-­‐butyl) zinc phthalocyanine (ZnPc), to exfoliated graphene sheets was achieved. The newly formed ZnPc-­‐graphene hybrid material was found soluble in common organic solvents without any precipitation for several weeks. Application of diverse spectroscopic techniques verified the successful formation of ZnPc-­‐graphene hybrid materi-­‐ al, while thermogravimetric analysis revealed the amount of ZnPc loading onto graphene. Microscopy analysis based on AFM and TEM was applied to probe the morphological characteristics and to investigate the exfoliation of graphene sheets. Efficient fluorescence quenching of ZnPc in the ZnPc-­‐graphene hybrid material suggested that photoinduced events occur from the photoexcited ZnPc to exfoliated graphene. The dynamics of the photoinduced electron transfer was evaluated by femtosecond transient absorption spectroscopy, thus, revealing the formation of transient species such as ZnPc+ yielding the charge-­‐separated state ZnPc•+–graphene•–. Finally, the ZnPc-­‐graphene hybrid material was integrated into a photoactive electrode of an optical transparent electrode (OTE) cast with nanostructured SnO2 films (OTE/SnO2), which exhibited sta le and reproducible photocurrent responses and the incident photon-­‐to-­‐current conversion efficien-­‐ cy was determine

Mechanistic pathways underlying altered neurovascular coupling in brain metastasis

Objectives: It is recognised that astrocytes form a physical bridge between neurons and the cerebrovasculature. Astrocytic end-feet help maintain endothelial tight junctions to support the blood–brain barrier (BBB) and release vasoactive molecules that regulate vascular tone. In secondary cancer (metastasis) to the brain, astrocytes are displaced from the vasculature and become activated, and we have shown that neurovascular coupling is compromised in rat model of brain metastasis (Serres et al., abstract submitted). The aim of this study, therefore, was to characterise the effects of astrocyte activation on astrocyte-vascular structure, vascularity and production of vasoactive molecules, using in vivo magnetic resonance imaging (MRI) and immunofluorescent microscopy. Methods: Two cohorts of BD-IX rats were injected intracortically in one node of the whisker barrel cortex pathway (the barrel field somatosensory cortex) with either (i) a lentivirus expressing ciliary neurotrophic factor (Lv-CNTF) known to switch astrocytic phenotype to an activated state, or (ii) a metastatic N-ethyl-N-nitrosourea-induced mammary adenocarcinoma cell line (ENU1546). Lv-CNTF injected animals were studied 6 weeks after intracortical injection, and ENU1546 injected animals were studied 1 week after injection. All animals underwent T1- and T2-weighted MRI to follow macroscopic structural changes, and post-gadolinium T1-weighted MRI to assess BBB integrity. Immunofluorescent microscopy was performed post-mortem to identify activated astrocytes (GFAP), neurons (NeuN), blood vessels (CD31), cyclooxygenase-1 and 2 (COX-1/2), inducible isoform of nitric oxide synthase (iNOS), glutathione (GSH), cytochrome p450 a precursor of 20-hydroxyeicosatetraenoic acid (20-HETE), alpha-smooth muscle actin (α-SMA) and proteoglycans of the basement membrane (β-dystroglycan). Results: In both cohorts, persistent activation of astrocytes, revealed by strong upregulation of GFAP, was observed in the injected cortex, which was not associated with BBB disruption as assessed by MRI. Disruption of the dystroglycan-laminin interaction was observed in the area of astrocyte activation causing dissociation of astrocytes from blood vessels, as shown by a lower immuno-colocalisation of blood vessel, astrocyte and β-dystroglycan, for both Lv-CNTF and ENU1546 injected animals (Fig1). Enlargement of blood vessels was also observed in both models. Together with structural changes in the astrocyte-vessel complex, upregulation of iNOS, COX-1, COX-2 and GSH were observed in activated astrocytes. Whilst upregulation of cytochrome p450 was observed in α-SMA-positive arterioles found in the area of astrocyte activation. Conclusion: Our findings suggest that astrocyte-vessel dissociation, leading to enlargement of blood vessels, together with dysregulation of signalling pathways controling vessel diameter likely underlie disruption of neurovascular coupling in brain metastasis. Upregulation of vasoconstrictory molecules (p450/20-HETE) at the arteriole end of the vascular bed may lead to reduced basal blood flow as observed in vivo (see Serres et al., submitted abstract) and suppression of response to stimulation, whilst upregulation of vasodilatory mediators (iNOS, COX, GSH) downstream of the arterioles may reduce vascular reserve and, hence, vascular responses to stimulation

Why do banks promise to pay par on demand?

We survey the theories of why banks promise to pay par on demand and examine evidence about the conditions under which banks have promised to pay the par value of deposits and banknotes on demand when holding only fractional reserves. The theoretical literature can be broadly divided into four strands: liquidity provision, asymmetric information, legal restrictions, and a medium of exchange. We assume that it is not zero cost to make a promise to redeem a liability at par value on demand. If so, then the conditions in the theories that result in par redemption are possible explanations of why banks promise to pay par on demand. If the explanation based on customers’ demand for liquidity is correct, payment of deposits at par will be promised when banks hold assets that are illiquid in the short run. If the asymmetric-information explanation based on the difficulty of valuing assets is correct, the marketability of banks’ assets determines whether banks promise to pay par. If the legal restrictions explanation of par redemption is correct, banks will not promise to pay par if they are not required to do so. If the transaction explanation is correct, banks will promise to pay par value only if the deposits are used in transactions. After the survey of the theoretical literature, we examine the history of banking in several countries in different eras: fourth-century Athens, medieval Italy, Japan, and free banking and money market mutual funds in the United States. We find that all of the theories can explain some of the observed banking arrangements, and none explain all of them

A phase-II study with idarubicin, etoposide and prednisone (IVPP), in patients with refractory or early relapsed intermediate or high grade non-Hodgkin's lymphoma

Haematologic

Evaluation of the prognostic and predictive value of HER family mRNA expression in high-risk early breast cancer: a Hellenic Cooperative Oncology Group (HeCOG) study

The aim of the study was to evaluate the prognostic ability of the transcriptional profiling of the HER family genes in early breast cancer, as well as to investigate the predictive value of HER2 mRNA expression for adjuvant treatment with paclitaxel. RNA was extracted from 268 formalin-fixed paraffin-embedded (FFPE) tumour tissue samples of high-risk breast cancer patients enrolled in the randomised HE10/97 trial, evaluating the effect of dose-dense anthracycline-based sequential adjuvant chemotherapy with or without paclitaxel. The mRNA expression of all four HER family members was assessed by kinetic reverse transcription-polymerase chain reaction (kRT-PCR). The overall concordance between kRT-PCR and IHC/FISH for HER2 status determination was 74%. At a median follow-up of 8 years, multivariate analysis showed that EGFR and HER2 mRNA expression was associated with reduced overall survival (OS). HER3 and HER4 mRNA level had a favourable prognostic value in terms of OS and disease-free survival (DFS), respectively. Adjusting for HER2 mRNA expression, OS and DFS did not differ between treatment groups. These data indicate that EGFR as well as HER2 are prognostic factors of worse clinical outcomes, whereas HER3 and HER4 gene transcription is associated with better prognosis in high-risk early breast cancer. However, HER2 mRNA expression did not predict clinical benefit from paclitaxel. Kinetic RT-PCR represents an alternative method for evaluating the expression of HER family members in FFPE breast carcinomas.Br J Cance

Early Geometrical Thinking in the Environment of Patterns, Mosaics and Isometries

This book discusses the learning and teaching of geometry, with a special focus on kindergarten and primary education. It examines important new trends and developments in research and practice, and emphasizes theoretical, empirical and developmental issues. Further, it discusses various topics, including curriculum studies and implementation, spatial abilities and geometric reasoning, as well as the psychological roots of geometrical thinking and teacher preparation in geometry education. It considers these issues from historical, epistemological, cognitive semiotic and educational points of view in the context of students' difficulties and the design of teaching and curricula