Optoelectronic properties of triphenylamine based dyes for solar cell applications. A DFT study

Indexación: Scopus.GSM thanks to the Department of Chemistry at the Universidad Andres Bello, Concepcion, Chile. LHMH gratefully acknowledges financial support from CONACYT (Projects CB2015-257823) and to the Universidad Autónoma del Estado de Hidalgo.Dye-sensitized solar cells (DSSCs) based on triphenylamine (TPA) as a donor group linked with the acceptor cyanoacrylic acid electron acceptor by 2,2'-bithiophene as π-bridged (D-π-A) has been investigated by Density Functional Theory (DFT) at the B3LYP/6-311G(d,p) level of theory, to establish the conformational orientation of cyanoacrylic acid group as well as evaluate the effect of planarizing the 2,2'-bithiophene unit in position 3 and 3' by electron withdrawing or donor groups on the electronic structure properties of ground and doping(n,p) states. Also, the Time Dependent Density Functional Theory (TD-DFT) at the CPCM-TD-CAM-B3LYP//CAM-B3LYP/6-311G(d,p) level of theory were selected to modulate the electronic absorption spectra and charge-transfer capabilities of the molecules analyzed in the present work. The results indicate that adding an auxiliary donor or withdrawing group to the 2,2'-bithiophene in the (D-π-A) arrangement allow to modify the LUMO's energy of the dyes, while the HOMO's energy is slightly affected. © 2018 Sociedade Brasileira de Quimica. All rights reserved.http://quimicanova.sbq.org.br/imagebank/pdf/AR20170232.pd

SEROLOGICAL IMMUNE RESPONSE AGAINST ADAM10 IN COLORECTAL CANCER PATIENTS IS A FAVORABLE SIGNATURE

In cancer the immune system is activated in response to qualitative and quantitative aberrant expression by tumor cells of certain proteins named tumor-associated antigens (TAAs). In a previous study in the laboratory, has been investigated the presence of TAAs inducing auto-antibodies (auto-Abs) in the Colorectal cancer (Crc) by exploiting the patients serological reactivity against the surface membrane proteoma. Among several candidates, a specific immunoreactivity against A Disintegrin And Metalloprotease 10 (ADAM10) protein has been identify.ADAM10 is a disintegrin metalloprotease with a potential role in tumor progression and invasion due to its sheddase activity. ADAM10 is able to promote ERK1/2 signaling activation promoting cell proliferation by the cleavage of the extracellular domain (ECD) of the HER2 tyrosine kinase receptor, which is released in serum. Moreover, ADAM10 plays a critical physiological function in the epithelial morphogenesis since its sheddase activity is crucial for the cell migration and extracellular matrix (ECM) remodelling, a phenomenon that also drives tumor metastasis. Thus, an aberrant expression of the ADAM10 in epithelial tissues might elicit a specific serological immune response. The serological screening performed on purified ADAM10, showed a significant presence of immunoreactivity against ADAM10 in the sera from patients affected by tumors of epithelial origin like Crc, Pancreatic cancer (Pc) and Breast cancer (Brc) if compared with serological reactivity of healthy subjects. On the contrary, sera from patients affected by hematological malignancies such as chronic lymphocytic leukemia (B-CLL) and Multiple Myeloma (MM), did not showed significant immunoreactivity against ADAM10. These results suggested that the presence of auto-Abs against ADAM10 in patients sera might be a candidate biomarker for carcinomas of epithelial origin. Since it is known that ADAM10 is overexpressed in advanced stages of the Crc disease, when the lymph nodes are infiltrated\u2003by the tumor, we evaluated the disease course of this patients after surgical resection in order to define whether the presence of auto-Abs anti-ADAM10 is a favourable or detrimental signature, correlating the immunoreactivity with the patients follow-up. The results showed that the presence of auto-Abs anti-ADAM10 prolonged significantly the disease-free condition if compared with Crc patients without serological immunoreactivity against ADAM10. Thus, in order to investigate the effects of these auto-Abs, in vitro experiments of both HER2 ECD release and cell migration were performed using the Colon carcinoma cell line LoVo. Results showed that commercial anti-ADAM10 antibodies resulted to be effective in inhibiting cell migration and HER2 ECD release in LoVo cell line while IgG fraction purified from representative Crc patients did not. This lack of inhibition might be the consequence of the fact that LoVo cell line did not express the specific epitope that elicited the serological reactivity in Crc patients. In fact, Crc patients showed different expression of ADAM10 in tumoral tissues. Patients with a positive immunoreactivity against ADAM10 (Ser-ADAM10 +) showed an overexpression of the inactive form of ADAM10 and, accordingly, an high expression of the inactive HER2 (p195) isoform and a decreased expression of phosphorilated-ERK1/2. These results suggest a reduced activity of ADAM10 on the HER2 ECD cleaveage which is supported by the observation that Ser-ADAM10 + patients showed lower HER2 ECD concentrations in serum compared to Ser-ADAM10 - patients. In conclusion, the presence of auto-antibodies anti-ADAM10 may be considered a biomarker of favourable prognosis for Crc patients at advanced stages of the disease that reflects an overexpression of inactive ADAM10 during the cell transformation and accordingly the lower protein maturation leads to a decrease of its sheddase activity which in turnt declines the proliferative and invasive capacity of tumor cells

Hyperkahler sigma models on cotangent bundles of Hermitian symmetric spaces using projective superspace

Kahler manifolds have a natural hyperkahler structure associated with (part of) their cotangent bundles. Using projective superspace, we construct four-dimensional N = 2 models on the tangent bundles of some classical Hermitian symmetric spaces (specifically, the four regular series of irreducible compact symmetric Kahler manifolds, and their non-compact versions). A further dualization yields the Kahler potential for the hyperkahler metric on the cotangent bundle.Comment: 47 pages, typos corrected, version accepted by JHE

Properties of hyperkahler manifolds and their twistor spaces

We describe the relation between supersymmetric sigma-models on hyperkahler manifolds, projective superspace, and twistor space. We review the essential aspects and present a coherent picture with a number of new results.Comment: 26 pages. v2: Sign mistakes corrected; Kahler potential explicitly calculated in example; references added. v3: Published version--several small clarifications per referee's reques

The Spectrum of the Dirac Operator on Coset Spaces with Homogeneous Gauge Fields

The spectrum and degeneracies of the Dirac operator are analysed on compact coset spaces when there is a non-zero homogeneous background gauge field which is compatible with the symmetries of the space, in particular when the gauge field is derived from the spin-connection. It is shown how the degeneracy of the lowest Landau level in the recently proposed higher dimensional quantum Hall effect is related to the Atiyah-Singer index theorem for the Dirac operator on a compact coset space.Comment: 25 pages, typeset in LaTeX, uses youngtab.st

Human anti-anthrax protective antigen neutralizing monoclonal antibodies derived from donors vaccinated with anthrax vaccine adsorbed

BACKGROUND: Potent anthrax toxin neutralizing human monoclonal antibodies were generated from peripheral blood lymphocytes obtained from Anthrax Vaccine Adsorbed (AVA) immune donors. The anti-anthrax toxin human monoclonal antibodies were evaluated for neutralization of anthrax lethal toxin in vivo in the Fisher 344 rat bolus toxin challenge model. METHODS: Human peripheral blood lymphocytes from AVA immunized donors were engrafted into severe combined immunodeficient (SCID) mice. Vaccination with anthrax protective antigen and lethal factor produced a significant increase in antigen specific human IgG in the mouse serum. The antibody producing lymphocytes were immortalized by hybridoma formation. The genes encoding the protective antibodies were rescued and stable cell lines expressing full-length human immunoglobulin were established. The antibodies were characterized by; (1) surface plasmon resonance; (2) inhibition of toxin in an in vitro mouse macrophage cell line protection assay and (3) in vivo in a Fischer 344 bolus lethal toxin challenge model. RESULTS: The range of antibodies generated were diverse with evidence of extensive hyper mutation, and all were of very high affinity for PA83~1 × 10(-10-11)M. Moreover all the antibodies were potent inhibitors of anthrax lethal toxin in vitro. A single IV dose of AVP-21D9 or AVP-22G12 was found to confer full protection with as little as 0.5× (AVP-21D9) and 1× (AVP-22G12) molar equivalence relative to the anthrax toxin in the rat challenge prophylaxis model. CONCLUSION: Here we describe a powerful technology to capture the recall antibody response to AVA vaccination and provide detailed molecular characterization of the protective human monoclonal antibodies. AVP-21D9, AVP-22G12 and AVP-1C6 protect rats from anthrax lethal toxin at low dose. Aglycosylated versions of the most potent antibodies are also protective in vivo, suggesting that lethal toxin neutralization is not Fc effector mediated. The protective effect of AVP-21D9 persists for at least one week in rats. These potent fully human anti-PA toxin-neutralizing antibodies are attractive candidates for prophylaxis and/or treatment against Anthrax Class A bioterrorism toxins

Noncommutative Quantum Mechanics and rotating frames

We study the effect of noncommutativity of space on the physics of a quantum interferometer located in a rotating disk in a gauge field background. To this end, we develop a path-integral approach which allows defining an effective action from which relevant physical quantities can be computed as in the usual commutative case. For the specific case of a constant magnetic field, we are able to compute, exactly, the noncommutative Lagrangian and the associated shift on the interference pattern for any value of $\theta$.Comment: 17 pages, presentation improved, references added. To appear in Physical Review

Modular Invariance and Characteristic Numbers

We show that a general miraculous cancellation formula, the divisibility of certain characteristic numbers and some other topologiclal results are con- sequences of the modular invariance of elliptic operators on loop spaces. Previously we have shown that modular invariance also implies the rigidity of many elliptic operators on loop spaces.Comment: 14 page

T violation and the unidirectionality of time

An increasing number of experiments at the Belle, BNL, CERN, DA{\Phi}NE and SLAC accelerators are confirming the violation of time reversal invariance (T). The violation signifies a fundamental asymmetry between the past and future and calls for a major shift in the way we think about time. Here we show that processes which violate T symmetry induce destructive interference between different paths that the universe can take through time. The interference eliminates all paths except for two that represent continuously forwards and continuously backwards time evolution. Evidence from the accelerator experiments indicates which path the universe is effectively following. This work may provide fresh insight into the long-standing problem of modeling the dynamics of T violation processes. It suggests that T violation has previously unknown, large-scale physical effects and that these effects underlie the origin of the unidirectionality of time. It may have implications for the Wheeler-DeWitt equation of canonical quantum gravity. Finally it provides a view of the quantum nature of time itself.Comment: 24 pages, 5 figures. Final version accepted for publishing in Foundations of Physics. The final publication is available at http://www.springerlink.com/content/y3h4174jw2w78322

Lorentz-invariant CPT violation

A Lorentz-invariant CPT violation, which may be termed as long-distance CPT violation in contrast to the familiar short-distance CPT violation, has been recently proposed. This scheme is based on a non-local interaction vertex and characterized by an infrared divergent form factor. We show that the Lorentz covariant $T^{\star}$-product is consistently defined and the energy-momentum conservation is preserved in perturbation theory if the path integral is suitably defined for this non-local theory, although unitarity is generally lost. It is illustrated that T violation is realized in the decay and formation processes. It is also argued that the equality of masses and decay widths of the particle and anti-particle is preserved if the non-local CPT violation is incorporated either directly or as perturbation by starting with the conventional CPT-even local Lagrangian. However, we also explicitly show that the present non-local scheme can induce the splitting of particle and anti-particle mass eigenvalues if one considers a more general class of Lagrangians.Comment: 28 pages; note added in proof; version published in Eur. Phys. J. C (2013) 73: 234