Observational epidemiological study to identify the clinical profile of naïve patients starting antiretroviral (ARV) therapy in Spain

Purpose of the study: To identify the proportion of patients starting ARV treatment with NNRTIs or with a PI/r and to explore and compare their clinical profile establishing different factors whereby physicians select the initial ARV treatment in a Spanish clinical setting. Methods: An observational study was conducted in two different phases. In Phase I a cross-sectional registration was conducted for patients who initiated ARV treatment in a 6-month period in 65 Spanish hospitals. In Phase II clinical and social-demographic features were collected retrospectively of patients who visited HIV clinics between August and November 2010 who had started ARV treatment containing an NNRTIs or a PI/r in Phase I. Summary of results: In Phase I, 1,687 subjects who initiated ARV treatment were registered, of which 53% started with an NNRTI-based regimen whereas 42% started with a PI/r-based regimen. Two percent of the treatment initiations occurred in a clinical trial. In Phase II, 642 patients were paired consecutively and retrospectively. The group of patients was composed of predominantly male subjects (81% vs 19%). The median time between diagnosis and the start of ARV treatment was 3.6±5.3 years. At the initiation of treatment, 72% of patients had a CD4 count below 350 cells/µl. Although treatment based on NNRTIs in naïve patients is the most frequent option in Spain, the analysis of clinical profiles shows that PI/r-based therapy is more often used than NNRTIs with statistical significance in patients with high viral load, Fig. A (≥100.000 copies/ml) (58% vs 42%; OR:1,75; 95% CI: 1,26–2,43; p<0,01), with CD4 cell counts <200 cells/µl, Fig. B (68% vs 31%; OR: 2,92; 95% CI: 1,99–4,27; p<0,01), and in patients at CDC stage C (65% vs 35%; OR: 2,05; CI: 1,27–3,31; p<0,01). Conclusions: In Spain, HIV is still diagnosed late (as measured by CD4 count<350 cells/µl). Treatment based on NNRTIs are more frequently used in naïve patients, although PIs/r-based regimens play an important role being the preferred option in patients with high viral load (≥100.000 copies/ml) and low CD4 cell count (<200 cells/µl)

In situ surface coverage analysis of RuO₂-catalysed HCl oxidation reveals the entropic origin of compensation in heterogeneous catalysis

In heterogeneous catalysis, rates with Arrhenius-like temperature dependence are ubiquitous. Compensation phenomena, which arise from the linear correlation between the apparent activation energy and the logarithm of the apparent pre-exponential factor, are also common. Here, we study the origin of compensation and find a similar dependence on the rate-limiting surface coverage term for each Arrhenius parameter. This result is derived from an experimental determination of the surface coverage of oxygen and chlorine species using temporal analysis of products and prompt gamma activation analysis during HCl oxidation to Cl2 on a RuO2 catalyst. It is also substantiated by theory. We find that compensation phenomena appear when the effect on the apparent activation energy caused by changes in surface coverage is balanced out by the entropic configuration contributions of the surface. This result sets a new paradigm in understanding the interplay of compensation effects with the kinetics of heterogeneously catalysed processes

Reliability and validity of an instrument that uses photographs to measure the ability for differential diagnosis of injuries caused by pressure and/or incontinence

Indexación: Scopus; Scielo.Objetivo: Evaluar la fiabilidad y validez de un instrumento que permite medir la habilidad visual para identificar y clasificar Dermatitis Asociada a Incontinencia (DAI), Ulceras por Presión (UPP) y lesiones mixtas, por parte de profesionales de enfermería. Material y método: Se aplicó un instrumento autoadministrado conformado por 14 fotografías a una muestra por conveniencia de 28 profesionales de enfermería, donde se debía identificar la lesión y luego clasificar su estado de avance. A modo exploratorio se calculó la fiabilidad anidada con Alpha de Cronbach y la validez con Análisis de Componentes Principales (ACP). Resultados: La fiabilidad inicial de las 14 fotografías (Alpha de Cronbach= 0,174) fue baja y tras eliminar 7 la fiabilidad fue aceptable (Alpha de Cronbach= 0,709). Se estableció la presencia de dos dimensiones: por un lado, la habilidad de diagnosticar DAI que explica un 35% de la varianza y, por otro, la habilidad de diagnosticar UPP, que explica el 22% de la varianza, ya sea que se encuentren separadas o juntas en un mismo paciente. Las lesiones DAI son diagnosticadas en mayor proporción que las lesiones mixtas. Conclusión: El estudio aportó 6 fotografías fiables y válidas que pueden ser utilizadas en futuros trabajos para construir un instrumento más robusto que pueda ser utilizado en Chile para la capacitación en el área. La muestra estudiada tiene fortalezas en el diagnóstico de DAI y dificultades en el diagnóstico de lesiones mixtas.Aim: To evaluate the reliability and validity of an instrument that allows to measure the visual ability to identify and classify Incontinence Associated Dermatitis (IAD), Pressure Ulcers (PU) and mixed lesions, by nursing professionals. Material and method: A self-administered instrument consisting of 14 photographs was applied to a convenience sample of 28 nurses. A set of 14 photographs were shown in which they were asked to identify and then classify the state of the lesion. In an exploratory manner, the nested reliability was calculated with Cronbach’s Alpha and the validity with Principal Component Analysis (PCA). Results: The initial reliability of the 14 photographs was low (Cronbach Alpha = 0.174), after removing 7 photographs the reliability became acceptable (Cronbach Alpha = 0.709). The presence of two dimensions was established: on the one hand the ability to diagnose IAD, which explains 35% of the variance, and secondly, the ability to diagnose PU, which explains 22% of the variance, whether they are separated or together in the same patient. IAD is better diagnosed than mixed lesions. Conclusion: The study provided 6 reliable and valid photos that can be used in future work to build a more robust instrument that can be used in Chile for training in the area. The studied sample shows strengths when diagnosing IAD and difficulties when diagnosing mixed lesions. © 2017, Universidad de Concepcion. All rights reserved.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-95532017000300059&lng=en&nrm=iso&tlng=e

Accessing Sodium Ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands : structural, synthetic, and magnetic insights

This study reports the synthesis and single-crystal X-ray crystallographic, NMR spectroscopic, and magnetic characterization of a series of sodium ferrates using bis(amide) Fe(HMDS)2 as a precursor (HMDS = 1,1,1,3,3,3-hexamethyldisilazide). Reaction with sodium reagents NaHMDS and NaCH2SiMe3 in hexane afforded donor-solvent-free sodium ferrates [{NaFe(HMDS)3}∞] (1) and [{NaFe(HMDS)2(CH2SiMe3)}∞] (2), respectively, which exhibit contacted ion pair structures, giving rise to new polymeric chain arrangements made up of a combination of inter- and intramolecular Na···Me(HMDS) electrostatic interactions. Addition of the unsaturated NHC IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) to 1 and 2 caused deaggregation of their polymeric structures to form discrete NHC-stabilized solvent-separated ion pairs [Na(IPr)2]+[Fe(HMDS)3]- (3) and [(THF)3·NaIPr]+[Fe(HMDS)2CH2SiMe3]- (4), where in both cases, the NHC ligand coordinates preferentially to Na. In contrast, when IPr is sequentially reacted with the single-metal reagents NaCH2SiMe3 and Fe(HMDS)2, the novel heteroleptic ferrate (THF)3Na[:C{[N(2,6-iPr2C6H3)]2CHCFe(HMDS)2}] (5) is obtained. This contains an anionic NHC ligand acting as an unsymmetrical bridge between the two metals, coordinating through its abnormal C4 position to Fe and its normal C2 position to Na. The formation of 5 can be described as an indirect ferration process where IPr is first metalated at the C4 position by the polar sodium alkyl reagent, which in turn undergoes transmetalation to the more electronegative Fe(HMDS)2 fragment. Treatment of 5 with 1 molar equiv of methyl triflate (MeOTf) led to the isolation and structural elucidation of the neutral abnormal NHC (aNHC) tricoordinate iron complex [CH3C{[N(2,6-iPr2C6H3)]2CHCFe(HMDS)2}] (6) with the subsequent elimination of NaOTf, disclosing the selectivity of complex 5 to react with this electrophile via its C2 position, leaving its Fe-C4 and Fe-N bonds intact. The magnetic susceptibility properties of compounds 1-6 have been examined. This study revealed a drastic change of magnetic susceptibility in replacing a pure σ donor from an idealized trigonal coordination environment by an NHC π donating character

Synthetic, structural and magnetic implications of introducing 2,2'-dipyridylamide to sodium-ferrate complexes

Using a transamination approach to access novel Fe(II) complexes, this study presents the synthesis, X-ray crystallographic and magnetic characterisation of a series of new iron complexes containing the multifunctional 2,2-dipyridylamide (DPA) ligand using iron bis(amide) [{Fe(HMDS)2}2] and sodium ferrate [{NaFe (HMDS)3}∞] (1) as precursors (HMDS = 1,1,1,3,3,3-hexamethyldisilazide). Reactions of DPA(H) with 1 show exceptionally good stoichiometric control, allowing access to heteroleptic [(THF)2·NaFe(DPA)(HMDS)2] (3) and homoleptic [{THF·NaFe(DPA)3}∞] (4) by using 1 and 3 equivalents of DPA(H) respectively. Linking this methodology and co-complexation, which is a more widely used approach to prepare heterobimetallic complexes, 3 can also be prepared by combining NaHMDS with heteroleptic [{Fe(DPA)(HMDS)}2] (2). In turn, 2 has been also synthesised and structurally defined by reacting [{Fe(HMDS)2}2] with two equivalents of DPA(H). Structural studies demonstrate the coordination flexibility of the N-bridged bis(heterocycle) ligand DPA, with 2 and 3 exhibiting discrete monomeric motifs, whereas 4 displays a much more intricate supramolecular structure, with one of its DPA ligands coordinating in an anti/anti fashion (as opposed to 2 and 3 where DPA shows a syn/syn conformation), which facilitates propagation of the structure via its central amido N. Magnetic studies confirmed the high-spin electron configuration of the iron(II) centres in all three compounds and revealed the existence of weak ferromagnetic interactions in dinuclear compound 2 ( J = 1.01 cm−1)

Accessing sodium ferrate complexes containing neutral and anionic N-heterocyclic carbene ligands: structural, synthetic, and magnetic insights

This study reports the synthesis and single-crystal X-ray crystallographic, NMR spectroscopic, and magnetic characterization of a series of sodium ferrates using bis(amide) Fe(HMDS)2 as a precursor (HMDS = 1,1,1,3,3,3- hexamethyldisilazide). Reaction with sodium reagents NaHMDS and NaCH2SiMe3 in hexane afforded donor-solvent-free sodium ferrates [{NaFe(HMDS)3}∞] (1) and [{NaFe(HMDS)2(CH2SiMe3)}∞] (2), respectively, which exhibit contacted ion pair structures, giving rise to new polymeric chain arrangements made up of a combination of inter- and intramolecular Na··· Me(HMDS) electrostatic interactions. Addition of the unsaturated NHC IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2- ylidene) to 1 and 2 caused deaggregation of their polymeric structures to form discrete NHC-stabilized solvent-separated ion pairs [Na(IPr)2]+[Fe(HMDS)3]− (3) and [(THF)3·NaIPr]+[Fe(HMDS)2CH2SiMe3]− (4), where in both cases, the NHC ligand coordinates preferentially to Na. In contrast, when IPr is sequentially reacted with the single-metal reagents NaCH2SiMe3 and Fe(HMDS)2, the novel heteroleptic ferrate (THF)3Na[:C{[N(2,6-iPr2C6H3)]2CHCFe(HMDS)2}] (5) is obtained. This contains an anionic NHC ligand acting as an unsymmetrical bridge between the two metals, coordinating through its abnormal C4 position to Fe and its normal C2 position to Na. The formation of 5 can be described as an indirect ferration process where IPr is first metalated at the C4 position by the polar sodium alkyl reagent, which in turn undergoes transmetalation to the more electronegative Fe(HMDS)2 fragment. Treatment of 5 with 1 molar equiv of methyl triflate (MeOTf) led to the isolation and structural elucidation of the neutral abnormal NHC (aNHC) tricoordinate iron complex [CH3C{[N(2,6-iPr2C6H3)]2CHCFe- (HMDS)2}] (6) with the subsequent elimination of NaOTf, disclosing the selectivity of complex 5 to react with this electrophile via its C2 position, leaving its Fe−C4 and Fe−N bonds intact. The magnetic susceptibility properties of compounds 1−6 have been examined. This study revealed a drastic change of magnetic susceptibility in replacing a pure σ donor from an idealized trigonal coordination environment by an NHC π donating character

Scale-free Networks from Optimal Design

A large number of complex networks, both natural and artificial, share the presence of highly heterogeneous, scale-free degree distributions. A few mechanisms for the emergence of such patterns have been suggested, optimization not being one of them. In this letter we present the first evidence for the emergence of scaling (and smallworldness) in software architecture graphs from a well-defined local optimization process. Although the rules that define the strategies involved in software engineering should lead to a tree-like structure, the final net is scale-free, perhaps reflecting the presence of conflicting constraints unavoidable in a multidimensional optimization process. The consequences for other complex networks are outlined.Comment: 6 pages, 2 figures. Submitted to Europhysics Letters. Additional material is available at http://complex.upc.es/~sergi/software.ht

A mental number line in human newborns

Humans represent numbers on a mental number line with smaller numbers on the left and larger numbers on the right side. A left\u2010to\u2010right oriented spatial\u2013numerical association, (SNA), has been demonstrated in animals and infants. However, the possibility that SNA is learnt by early exposure to caregivers\u2019 directional biases is still open. We conducted two experiments: in Experiment 1, we tested whether SNA is present at birth and in Experiment 2, we studied whether it depends on the relative rather than the absolute magnitude of numerousness. Fifty\u2010five\u2010hour\u2010old newborns, once habituated to a number (12), spontaneously associated a smaller number (4) with the left and a larger number (36) with the right side (Experiment 1). SNA in neonates is not absolute but relative. The same number (12) was associated with the left side rather than the right side whenever the previously experienced number was larger (36) rather than smaller (4) (Experiment 2). Control on continuous physical variables showed that the effect is specific of discrete magnitudes. These results constitute strong evidence that in our species SNA originates from pre\u2010linguistic and biological precursors in the brain

Signatures of arithmetic simplicity in metabolic network architecture

Metabolic networks perform some of the most fundamental functions in living cells, including energy transduction and building block biosynthesis. While these are the best characterized networks in living systems, understanding their evolutionary history and complex wiring constitutes one of the most fascinating open questions in biology, intimately related to the enigma of life's origin itself. Is the evolution of metabolism subject to general principles, beyond the unpredictable accumulation of multiple historical accidents? Here we search for such principles by applying to an artificial chemical universe some of the methodologies developed for the study of genome scale models of cellular metabolism. In particular, we use metabolic flux constraint-based models to exhaustively search for artificial chemistry pathways that can optimally perform an array of elementary metabolic functions. Despite the simplicity of the model employed, we find that the ensuing pathways display a surprisingly rich set of properties, including the existence of autocatalytic cycles and hierarchical modules, the appearance of universally preferable metabolites and reactions, and a logarithmic trend of pathway length as a function of input/output molecule size. Some of these properties can be derived analytically, borrowing methods previously used in cryptography. In addition, by mapping biochemical networks onto a simplified carbon atom reaction backbone, we find that several of the properties predicted by the artificial chemistry model hold for real metabolic networks. These findings suggest that optimality principles and arithmetic simplicity might lie beneath some aspects of biochemical complexity

The solvation and dissociation of 4-benzylaniline hydrochloride in chlorobenzene

A reaction scheme is proposed to account for the liberation of 4-benzylaniline from 4-benzylaniline hydrochloride, using chlorobenzene as a solvent at a temperature of 373 K. Two operational regimes are explored: “closed” reaction conditions correspond to the retention of evolved hydrogen chloride gas within the reaction medium, whereas an “open” system permits gaseous hydrogen chloride to be released from the reaction medium. The solution phase chemistry is analyzed by 1H NMR spectroscopy. Complete liberation of solvated 4-benzylaniline from solid 4-benzylaniline hydrochloride is possible under “open” conditions, with the entropically favored conversion of solvated hydrogen chloride to the gaseous phase thought to be the thermodynamic driver that effectively controls a series of interconnecting equilibria. A kinetic model is proposed to account for the observations of the open system