One-Loop Off-Shell Amplitudes from Classical Equations of Motion.

In this Letter, we present a recursive method for computing one-loop off-shell integrands in colored quantum field theories. First, we generalize the perturbiner method by recasting the multiparticle currents as generators of off-shell tree-level amplitudes. After, by taking advantage of the underlying color structure, we define a consistent sewing procedure to iteratively compute the one-loop integrands. When gauge symmetries are involved, the whole procedure is extended to multiparticle solutions involving ghosts, which can then be accounted for in the full loop computation. Since the required input here is equations of motion and gauge symmetry, our framework naturally extends to one-loop computations in certain non-Lagrangian field theories.

Gut Microbiota as a Potential Predictive Biomarker in Relapsing-Remitting Multiple Sclerosis.

BACKGROUND: The influence of the microbiome on neurological diseases has been studied for years. Recent findings have shown a different composition of gut microbiota detected in patients with multiple sclerosis (MS). The role of this dysbiosis is still unknown. OBJECTIVE: We analyzed the gut microbiota of 15 patients with active relapsing-remitting multiple sclerosis (RRMS), comparing with diet-matched healthy controls. METHOD: To determine the composition of the gut microbiota, we performed high-throughput sequencing of the 16S ribosomal RNA gene. The specific amplified sequences were in the V3 and V4 regions of the 16S ribosomal RNA gene. RESULTS: The gut microbiota of RRMS patients differed from healthy controls in the levels of the Lachnospiraceae, Ezakiella, Ruminococcaceae, Hungatella, Roseburia, Clostridium, Shuttleworthia, Poephyromonas, and Bilophila genera. All these genera were included in a logistic regression analysis to determine the sensitivity and the specificity of the test. Finally, the ROC (receiver operating characteristic) and AUC with a 95% CI were calculated and best-matched for Ezakiella (AUC of 75.0 and CI from 60.6 to 89.4) and Bilophila (AUC of 70.2 and CI from 50.1 to 90.4). CONCLUSIONS: There is a dysbiosis in the gut microbiota of RRMS patients. An analysis of the components of the microbiota suggests the role of some genera as a predictive factor of RRMS prognosis and diagnosis.

Multiparticle Solutions to Einstein's Equations.

In this Letter, we present the first multiparticle solutions to Einstein's field equations in the presence of matter. These solutions are iteratively obtained via the perturbiner method, which can circumvent gravity's infinite number of vertices with the definition of a multiparticle expansion for the inverse spacetime metric as well. Our construction provides a simple layout for the computation of tree level field theory amplitudes in D spacetime dimensions involving any number of gravitons and matter fields, with or without supersymmetry.

Cosmological Scattering Equations.

We propose a world sheet formula for tree-level correlation functions describing a scalar field with arbitrary mass and quartic self-interaction in de Sitter space, which is a simple model for inflationary cosmology. The correlation functions are located on the future boundary of the spacetime and are Fourier-transformed to momentum space. Our formula is supported on mass-deformed scattering equations involving conformal generators in momentum space and reduces to the CHY formula for ϕ^{4} amplitudes in the flat space limit. Using the global residue theorem, we verify that it reproduces the Witten diagram expansion at four and six points, and sketch the extension to n points.

Estudio de alteraciones neurocognitivas en pacientes infectados por el virus de la inmunodeficiencia humana / Study of neurocognitive alterations in patients infected by the human immunodeficiency virus

El virus de inmunodeficiencia humana, conocido por su impacto en el sistema inmunológico, ocasionamanifestacionesneurológicas progresivas con afectación cognitiva, perturbando funciones de atención, memoria, lenguaje, ejecución y procesamiento de la información, lo cual interfiere de forma negativa en la vida social, laboral y familiar del paciente. Objetivos: Evaluar las alteraciones de diferentes funciones neurocognitivas de los pacientes con infección por el virusde inmunodeficienciahumana, en una institución prestadora de servicios de salud de la cuidad de Ibagué - Colombia. Método: Se utilizó la Evaluación Cognitiva Montreal (MoCA), la cual fue diseñada como un instrumento ágil para determinar alteraciones cognitivas leves. La población objeto de estudio la constituyeron 44 pacientes portadores de virus de inmunodeficiencia humana, seleccionados dentro de un marco de muestreo no-probabilístico con muestra intencional o de conveniencia, entre los 14 y 75 años de edad. Resultados: Mayor deterioro neurocognitivo en los pacientes diagnosticados con virus de inmunodeficiencia humana de mayor edad; datos epidemiológicos indican que la edad más avanzada se asocia a una mayor prevalencia de desorden neurocognitivo asociado al virus de inmunodeficiencia humana. Conclusiones: El estudio de los mecanismos del deterioro neurocognitivo en pacientes con virus de inmunodeficiencia humana se hace cada vez más relevante, porque cada día aumenta su esperanza de vida, pero a su vez genera complicaciones con mayor predominio de la comorbilidad médica, psiquiátrica y neurológica(AU)

Introduction: The Human Immunodeficiency Virus, known for its impact on the immune system, causes progressive neurologic manifestations with cognitive impairment, disrupting attention functions, memory, language, execution and processing of information. The latter negatively interferes in social, work and family life of the patient. Objectives: To evaluate alterations in varied neurocognitive functions on patients with Human Immunodeficiency Virusinfection, at a health institution in Ibague, Colombia. Method: The Montreal Cognitive Assessment (MoCA) was used. It was designed as a tool to determine mild cognitive alterations. The study population was made up of 44 carriers of Human Immunodeficiency Virus who were selected within a framework of non-probabilistic sampling and with purposive sample or convenience, between 14 and 75 years old. Results: Greater neurocognitive impairment in patients diagnosed with Human Immunodeficiency Virus in legal age; someepidemiological data indicate that the older age is associated with a higher prevalence of neurocognitive disorder associated with Human Immunodeficiency Virus. Conclusions: The study of the neurocognitive impairment mechanisms in patients with Human Immunodeficiency Virus becomes increasingly more relevant, as their life expectancy increases daily. On the other hand, it causes complications with greater prevalence of medical psychiatric and neurological comorbidity(AU)

Nanogold - IgY antibodies. An immunoconjugated for the detection of house dust mite (Dermatophagoides) allergens.

Conjugation of avian IgY antibodies to nanosensors has been extensively explored for the diagnostics of virus and parasite infection, as well as for the detection of pharmaceutically and toxicologically relevant molecules. However, to date this strategy has only been minimally applied the detection of allergens. In this study, gold nanoparticles (GNPs) were conjugated to a polyvalent IgY antibodies raised against Dermatophagoides group I allergens. GNPs were synthesized by HAuCL4 reduction using 1% trisodium citrate, and characterized them by absorption spectroscopy and transmission electron microscopy (TEM). The most stable immunoconjugates were obtained with 18-nm monodisperse GNPs and a minimal concentration of 12.5 µg/mL of IgY at pH 7.5. The immunoconjugate was capable of detecting up to 1.5 µg of a total Dermatophagoides farinae protein extract in an immuno-dot blot assay. This immunoreactant conjugate represents a new tool for the detection and control of indoor dust mite allergens.

Fatty Acid Profile, Phenolics and Flavonoids Contents in Olea europaea L. Callus Culture cv. cornicabra.

Olive trees are one of the most important oil crops in the world due to the sensorial and nutritional characteristics of olive oil, such as lipid composition and antioxidant content, and the medicinal properties of its leaves. In this paper, callus formation was induced using nodal segments of olive tree (Olea europaea cv. cornicabra) as explants. Fatty acid profile, total phenolic compounds and total flavonoid compounds were determined in callus culture after 15 weeks and compared with leaf and nodal segments tissues. There was no statistical difference in phenolic compounds among leaf, nodal segments and callus culture, whereas flavonoid compounds were higher in leaf. Fatty acid profile was similar in leaf, nodal segments and callus culture and was constituted by hexadecanoic acid, octadecanoic acid, cis-9-octadecenoic acid, cis-9,12-octadecadienoic acid, cis-9,12,15-octadecatrienoic acid. Hexadecanoic acid was the main fatty acid in callus, leaf and nodal segments with 35.0, 39.0 and 40.0% (w/w), of the lipid composition, respectively. With this paper, it is being reported for the first time the capacity of callus culture to accumulate fatty acids. Our results could serve to continue studying the production of fatty acids in callus cultivation as a biotechnological tool to improve different olive cultivars.

Conformational Changes of Enzymes and Aptamers Immobilized on Electrodes.

Conformation constitutes a vital property of biomolecules, especially in the cases of enzymes and aptamers, and is essential in defining their molecular recognition ability. When biomolecules are immobilized on electrode surfaces, it is very important to have a control on all the possible conformational changes that may occur, either upon the recognition of their targets or by undesired alterations. Both enzymes and aptamers immobilized on electrodes are susceptible to conformational changes as a response to the nature of the charge of the surface and of the surrounding environment (pH, temperature, ionic strength, etc.). The main goal of this review is to analyze how the conformational changes of enzymes and aptamers immobilized on electrode surfaces have been treated in reports on biosensors and biofuel cells. This topic was selected due to insufficient information found on the actual conformational changes involved in the function of these bioelectrochemical devices despite its importance.

Template assisted electrochemical growth of cobalt nanowires: influence of deposition conditions on structural, optical and magnetic properties.

The influence of electrodeposition potential, pH, composition and temperature of the electrolytic bath on the structure of cobalt nanowires arrays electrodeposited into anodic aluminum oxide (AAO) porous membranes is reported. XRD, SEM, and TEM analysis were employed to characterize structural (crystal phase, crystallographic texture, and grain size), and morphological nanowire properties. It was confirmed that at pH 2 the electrodeposition potential has not influence on the preferred crystallographic orientation of the electrochemically grown Co nanowires. At pH 4 the electrodeposition potential controls the growth of cobalt nanowires along some preferential crystallographic planes. The electrolytic pH bath modulates the fcc or hcp phase exhibited by the cobalt nanowires. Single crystalline nanowires with a hcp phase strongly oriented along the (2021) crystallographic plane were obtained at pH 4 and at -1.1 V (vs. Ag/AgCl), a result not previously reported. High electrolytic bath temperatures contributed to improve the single crystalline character of the cobalt nanowires. The presence of chloride anion in the electrolytic bath also influenced on the structural properties of the resulting cobalt nanowires, improving their crystallinity. The optical reflectance of the samples shows a structure in the UV-blue region that can be assigned to the two-dimensional morphology arising in the shape of the almost parallel nanowires. Magnetic measurements showed that different electrodeposition potentials and electrolytic bath pH lead to different magnetic anisotropies on the nanowire array samples.

Single-crystal growth of nickel nanowires: influence of deposition conditions on structural and magnetic properties.

This paper examines the influence of electrodeposition potential, pore size, pH, composition, and temperature of the electrolytic bath on the structure of nickel nanowires arrays electrodeposited into anodic alumina oxide porous membranes. Scanning electron microscopy, X-ray diffraction, and transmission electron microscopy analysis were employed to characterize the structural and morphological properties of the nanowires. Results show that the electrodeposition potential controls the growth of nickel nanowires along some preferential crystallographic planes. At -0.90 V (vs. Ag/AgCl) single crystalline nanowires with a strong (111) orientation were obtained. High temperatures and a moderately acid pH solution contributed to improve the single crystalline character of nanowires. The presence of chloride ions produced polycrystalline nanowires at low temperature and single crystalline nanowires at high temperature. The influence of the electrodeposition potential in their magnetic anisotropies is also reported.

A chemical, morphological, and electrochemical (XPS, SEM/EDX, CV, and EIS) analysis of electrochemically modified electrode surfaces of natural chalcopyrite (CuFeS2) and pyrite (FeS2) in alkaline solutions.

Electrodic surfaces of natural chalcopyrite and natural pyrite minerals (El Teniente mine, Chile) have been studied by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy including microanalysis (SEM/EDX). For comparison, fractured and polished mineral surfaces were also studied by XPS. In both electrodes, the formation of Fe(III) species containing oxygen were detected and Cu(II) species containing oxygen were additionally detected for chalcopyrite at advanced oxidation states. The presence of Cu(II) species containing oxygen was not detected by XPS for the initial oxidation states of the chalcopyrite. For pyrite, the present results do not allow confirmation of the presence of polysulfurs such as have been previously proposed. In both minerals, the measurements of SEM and EDX show relevant alterations in the respective surfaces when different potential values were applied. The chalcopyrite surface shows the formation of protrusions with a high concentration of oxygen. The pyrite surface shows a layer of modified material with high oxygen content. The modifications detected by XPS, SEM, and EDX allowed the explanation of the complexity of the equivalent circuit used to simulate the experimental EIS data. At high oxidation states, both minerals showed a pseudoinductive loop in the equivalent circuit, which was due to the active electrodissolution of the minerals which takes place through a surface film previously formed.

DDT induces DNA damage in blood cells. Studies in vitro and in women chronically exposed to this insecticide.

In this study, DDT-induced DNA damage on blood cells was analyzed both in vitro and in vivo. Peripheral blood mononuclear cells (PBMC) were isolated from healthy donors and incubated in the presence of three different concentrations (40, 80, and 100 microg/mL) of p,p'-DDT, p,p'-DDE, and p,p'-DDD at three different treatment times (24, 48, and 72 h). Then, DNA damage was assessed by the single-cell electrophoresis assay (comet assay) as well as by flow cytometry detection of hypodiploid cells (DNA content assay). All compounds induced significant DNA damage as shown by the comet assay. Accordingly, cells exposed to DDT, DDE, and DDD showed a significant increase in the percentage of hypodiploid cells compared with untreated PBMC. In agreement with the in vitro data, a significant correlation between blood levels of DDT, DDD, and DDE and DNA damage (comet assay) was found in women with different amounts of environmental exposure. This association remained significant after controlling for nutritional status, smoking habits, alcohol ingestion, and reported exposure to other pesticides. Although the precise biological importance remains to be explained, our results strongly suggest that DDT and its metabolites are able to induce DNA damage in PBMC both in vitro and in vivo.

Factores de riesgo de accidentes en niños que consultaron al Policlínico Infantil de Medellín Diciembre 1 de 1998 - marzo 6 de 1999 / Risk factors for accidents in children that consulted to the emergency unit of San Vicente de Paul Children´s Hospital of Medellin, Colombia, December 1, 1998 - March 6, 1999

Se hizo un estudio descriptivo prospectivo para identificar los factores de riesgo para accidentes en los niños menores de 12 años que consultaron por esta causa al Policlínico Infantil de Medellín, desde diciembre 1 de 1998 hasta marzo 6 de 1999. Se compararon dichos factores durante un período de vacaciones escolares y uno de actividad académica de igual duración.Se trabajó con 1.185 pacientes. La distribución por sexo fue: 771 niños (65 por ciento) y 414 niñas (35 por ciento); el 76,9 por ciento (912 pacientes) procedían de Medellín y su área metropolitana. El lugar del accidente fue como sigue: en la calle 582 niños (49 por ciento); en el hogar 496 niños (41,9 por ciento), en la escuela 32 niños (2,7 por ciento) y en otros sitios 75 niños (6,3 por ciento). Se encontraban solos en el momento del accidente 199 niños (16,8 por ciento), con otros niños 512 (43,2 por ciento) y con adultos 474 (40 por ciento). El principal tipo de accidente fue el mecánico en 1.077 casos (90,9 por ciento); 740 niños sufrieron caídas lo que representó el 62,5 por ciento de todos los accidentes. El accidente por vehículos de motor representó el 10,3 por ciento (123 casos). El trauma fue leve en 1.128 niños (95,2 por ciento). La letalidad fue del 0,7 por ciento (8 niños), especialmente por trauma craneoencefálico debido a accidentes de tránsito y heridas por arma de fuego. El trauma fue más grave en los menores de 2 años.Se encontró diferencia estadísticamente significativa en la frecuencia de traumas entre el período de vacaciones y el académico, con más accidentes durante las vacaciones.Se recomienda iniciar programas de prevención de accidentes especialmente en el hogar, dirigidos a los padres y cuidadores de los menores, con énfasis en las etapas de desarrollo de los niños y los riesgos para los diferentes tipos de accidentes.