Site-selective adsorption of naphthalene-tetracarboxylic-dianhydride on Ag(110): First-principles calculations

The mechanism of adsorption of the 1,4,5,8-naphthalene-tetracarboxylic-dianhydride (NTCDA) molecule on the Ag(110) surface is elucidated on the basis of extensive density functional theory calculations. This molecule, together with its perylene counterpart, PTCDA, are archetype organic semiconductors investigated experimentally over the past 20 years. We find that the bonding of the molecule to the substrate is highly site-selective, being determined by electron transfer to the LUMO of the molecule and local electrostatic attraction between negatively charged carboxyl oxygens and positively charged silver atoms in [1-10] atomic rows. The adsorption energy in the most stable site is 0.9eV. A similar mechanism is expected to govern the adsorption of PTCDA on Ag(110) as well.Comment: 8 pages, 4 figures, high-quality figures available upon reques

Synthetic antigenic determinants of clavulanic acid induce dendritic cell maturation and specific T cell proliferation in patients with immediate hypersensitivity reactions

Background Immediate drug hypersensitivity reactions (IDHRs) to clavulanic acid (CLV) have increased in the last decades due to a higher consumption alongside amoxicillin (AX). Due to its chemical instability, diagnostic procedures to evaluate IDHRs to CLV are difficult, and current in vitro assays do not have an optimal sensitivity. The inclusion of the specific metabolites after CLV degradation, which are efficiently recognised by the immune system, could help to improve sensitivity of in vitro tests. Methods Recognition by dendritic cells (DCs) of CLV and the synthetic analogues of two of its hypothesised antigenic determinants (ADs) was evaluated by flow cytometry in 27 allergic patients (AP) and healthy controls (HC). Their ability to trigger the proliferation of T cells was also analysed by flow cytometry. Results The inclusion of synthetic analogues of CLV ADs, significantly increased the expression of maturation markers on DCs from AP compared to HC. A different recognition pattern could be observed with each AD, and, therefore, the inclusion of both ADs achieves an improved sensitivity. The addition of synthetic ADs analogues increased the proliferative response of CD4+Th2 compared to the addition of native CLV. The combination of results from both ADs increased the sensitivity of proliferative assays from 19% to 65% with a specificity higher than 90%. Conclusions Synthetic ADs from CLV are efficiently recognised by DCs with ability to activate CD4+Th2 cells from AP. The combination of analogues from both ADs, significantly increased the sensitivity of DC maturation and T-cell proliferation compared to native CLV.This work has been supported by Institute of Health ‘Carlos III’ (ISCIII) of the Ministry of Economy and Competitiveness (MINECO) (grants co-funded by European Regional Development Fund: PI15/01206, PI17/01237, PI18/00095, PI20/01734, RETICS ARADYAL RD16/0006/0001); Andalusian Regional Ministry of Health (grants PI-0241-2016, PE-0172-2018, PI-0127-2020); Spanish Ministerio de Ciencia e Innovación (Proyectos de I+D+I «Programación Conjunta Internacional», EuroNanoMed 2019 (PCI2019-111825-2), Ministerio de Ciencia y Educación (PID2019-104293GB-I00), Instituto de Salud Carlos III (ISCIII) of MINECO (RD16/0006/0012), Junta de Andalucía ( PY20_00384 ). AA and NPS hold Senior Postdoctoral Contracts (RH-0099-2020 and RH-0085-2020) from Andalusian Regional Ministry of Health (cofunded by European Social Fund (ESF): ‘Andalucía se mueve con Europa’). JLP holds a Sara Borrell fellowship (CD19/00250) by ISCIII of MINECO (cofunded by ESF, “El FSE invierte en futuro”). GB holds a ‘Juan Rodes’ contract (JR18/00054) by ISCIII of MINECO (cofunded by ESF). MIM holds a ‘Miguel Servet II’ grant (CPII20/00028) by ISCIII of MINECO (cofunded by ESF). ML holds a ‘Rio Hortega’ contract (CM20/00210) by ISCIII of MINECO (cofunded by ESF). CM holds a ‘Nicolas Monardes’ research contract by Andalusian Regional Ministry Health (RC-0004-2021). NMR experiments for characterizing molecule structures have been performed in the ICTS ‘NANBIOSIS’, by the U28 Unit at the Andalusian Centre for Nanomedicine and Biotechnology (BIONAND). Funding for open access charge: Universidad de Málag

The Bangko Sentral’s Business Expectations Survey

The BSP’s Business Expectations Survey (BES) was launched in 1986 but it was only in 2001 that it was harmonized with international business tendency survey practices. Based on survey results for the first six quarters, the harmonized BES appears to be a promising source of coincident and leading indicators of short-term business and economic performance in the Philippines.Business outlook, leading economic indicators

“Manipulation" of molecular orientation in ultrathin organic films: NTCDA on Ag(111)

The bonding of 1,4,5,8-naphthalene-tetracarboxylicacid-dianhydride (NTCDA) on Ag(111) and its molecular orientation were investigated by X-ray photoelectron (XPS) and near edge X-ray absorption fine-structure spectroscopy (NEXAFS). Vapour-deposited NTCDA films show high orientational order in the mono- and multi-layer regime. In the monolayer regime the molecules are strongly bound to the substrate via the conjugated π-system of the naphthalene core which leads to a parallel orientation of the molecular plane to the Ag(111) substrate. For thicker films (e.g., 150 Å) the molecular orientation strongly depends on the substrate temperature during preparation. Film preparation at 285 K results in upright standing molecules, whereas low substrate temperatures yield a uniform molecular orientation with the molecular plane parallel to the substrate. This behaviour is explained by the weak intermolecular interaction and the adsorption kinetics

Changes of intra-aneurysmal pressure during coiling - Reply

International audienc

Aluminium metallisation of argon and oxygen plasma-modified polycarbonate thin film surfaces

The influence of plasma treatment on the metallisation of polycarbonate surfaces was studied using X-ray absorption spectroscopy (XAFS) and core level X-ray photoelectron spectroscopy (XPS). Thin films of two different molecules were chosen: bis-phenol-A polycarbonate with phenol endgroups (P-PC) prepared ex situ by the spin-coating technique onto MoTe2{0001}surfaces, and the model compound bis-phenol-A polycarbonate (n=1) with tert-butyl phenyl endgroups (tBP-PC) evaporated in situ in UHV onto Cu{110}, Ag{100} and Ag{111} surfaces with film thicknesses of up to several monolayers. Surfaces of untreated samples and of samples which were pre-treated with either an inert argon or a reactive oxygen microwave plasma were metallised with Al (evaporated by electron beam heating) at film thicknesses ranging from the sub-monolayer region up to several monolayers. For the untreated surface, XAFS and XPS spectra suggest that the Al reacts with the carbonate groups leading to a breaking of the CO double bonds (and/or a reduction in bond order) as well as formation of Al oxide, Al hydroxide and Al–O–C linkages. A study of the time-dependent oxidation of the evaporated Al leads to the conclusion that Al slowly diffuses to the reactive sites in the first few subsurface layers of the polymer. Argon plasma treatment of samples leads to a reduction in the number of carbonyl groups in the near surface region. After metal deposition a higher ratio of metallic, non-reacted, Al was observed covering the polycarbonate surface and the diffusion rate into the polymer bulk seems to be higher than in the case of the untreated surface. Oxygen plasma treatment leads to the creation of additional CO containing species which also react with the Al in the subsequent metallisation process. Here, the ratio of oxidised Al on the polymer surface is higher than observed for untreated and argon plasma pre-treated polymer surfaces

Advances and novel developments in drug hypersensitivity diagnosis.

A correct diagnosis of drug hypersensitivity reactions (DHRs) is very important for both the patient and health system. However, DHRs diagnosis is complex, time consuming, requires trained personnel, is not standardized for many drugs, involves procedures not exempt of risk, and in most cases lacks standardized in vivo and in vitro tests. Thus, there is an urgent need for improving the different approaches to diagnose patients with suspected DHRs. In this review, we have analyzed the advances performed in immediate and nonimmediate DHRs diagnosis during the last two years and obtained several conclusions: the significant heterogeneity in current practice among centers illustrates the need to re-evaluate, update, and standardize in vivo tests and protocols for the diagnosis and management of patients with suspected drug allergy. Regarding in vitro tests, the latest studies have focused on increasing their sensitivity or on establishing the sensitivity and specificity for the tests performed with new drugs. There seems to be a consensus about combining in vivo and in vitro tests as the best way to increase the diagnostic accuracy

Argon plasma-induced modifications at the surface of polycarbonate thin films

The chemical modification of the surfaces of polycarbonate films by microwave-induced argon plasma treatment has been followed by X-ray absorption spectroscopy (XAFS) and core level photoemission spectroscopy (XPS). Measurements have been made on thin films of both ex-situ spin-coated bis-phenol-A polycarbonate with phenol endgroups and the model compound bis-phenol-A polycarbonate (n = 1) with tert-butyl phenyl endgroups evaporated in-situ in UHV on single crystal surfaces. A preferential orientation of a monolayer of the model compound on a Ag{111} surface was determined from the angular dependence of the XAFS spectra. Spectral features were assigned to contributing transitions within different moieties. Relatively mild microwave Ar plasma activation of the surfaces of both types of films led to a decrease in intensity of carbonyl features in both XAFS and XPS. Combined with the observation of new spectral features in XPS the data can be interpreted in terms of a formation of ester and ether groups in the near-surface region with possible cross-linking after desorption of CO or CO2