628 research outputs found
Improved water supply and water handling technologies: Revealed complements but perceived substitutes for safe water quality
We analyze the impact of public water infrastructure and water handling technologies on the water quality and water handling behavior of households in rural Benin using both quasi-experimental and experimental household-level panel data. We find that the installation of improved village-level water sources induces households to reduce water disinfection efforts at home, indicating that households perceive improved public water infrastructure as a substitute for improved water handling to obtain safe drinking water. Consequently, point-of-use drinking water quality does not change. A reduction of contamination with E. coli at points of use can only be achieved if interventions providing drinking water technologies at the water source are complemented by household-level interventions and efforts to teach households how to maintain good water quality.ISSN:2352-728
Optimización de la Síntesis Química del Precursor "2-(2'-nitrofenoxi)-acetato de metilo" partiendo del 2-nitrofenol
La Alelopatía es: “la ciencia que estudia procesos que implican metabolitos secundarios producidos por plantas, algas, bacterias y hongos que influyen en el crecimiento y desarrollo de sistemas cultivados y biológicos” y en el que, por tanto, se incluye cualquier interacción de las plantas con su medio ambiente.
En los últimos años, se viene desarrollando la búsqueda de nuevos herbicidas basados en metabolitos secundarios producidos por plantas que sean respetuosos con el medio ambiente, de buena degradabilidad, atóxicos para el ser humano, y que presenten la mejor respuesta posible ante los actuales, y cada vez más frecuentes, fenómenos de resistencia.
Los productos naturales de origen vegetal se presentan como una fuente atractiva de sustancias agroquímicas, no sólo por su diversidad estructural, sino por su acción biológica específica y su carácter inocuo “a priori” para el medio ambiente. Dentro de estos productos naturales vegetales de elevada actividad, se destacan los ácidos benzohidroxámicos (metabolitos secundarios con esqueletos de (2H)-1,4-benzoxacin-3(4H)-ona), que además, se trata de uno de los grupos de aleloquímicos mayormente estudiados. Entre los de mayor interés, se encuentra el D-DIBOA (4-hidroxi-(2H)-1,4-benzoxacin-3(4H)-ona), que presenta elevadas fitotoxicidad y estabilidad y muy buena degradabilidad en suelos de cultivo. Además, la producción de 6-Cl-D-DIBOA presenta alta actividad y 8-Cl-D-DIBOA alta selectividad frente a diferentes especies.
La síntesis de ácidos benzohidroxámicos (benzoxacinonas) tiene lugar en dos etapas. La primera de ellas consiste en una reacción de sustitución nucleofílica de los productos comerciales derivados del 2-nitrofenol con diferentes sustituyentes en el anillo bencénico. La segunda etapa se trata de una reacción de reducción del grupo nitro aromático.
Debido al riesgo de explosión que implica la segunda etapa de reacción, que se trata de una reacción de catálisis heterogénea exotérmica con desprendimiento de hidrógeno, se exploraron nuevas alternativas.
La segunda etapa, como se estudió en el Proyecto Colaborativo“P06-TEP-01399 (Producción Biotecnológica de Ácidos Benzohidroxámicos Bioactivos)”, también se puede llevar a cabo mediante una biotransformación con la utilización de E.coli.
El presente trabajo se enmarca dentro de un proyecto de excelencia concedido por la Junta de Andalucía en el año 2014, cuyo objetivo general es la producción biotecnológica de D-DIBOA mediante la mejora genética de Escherichia coli., así como la optimización global del proceso de biotransformación.
Tanto para la síntesis de D-DIBOA a escala de laboratorio, como para su producción biotecnológica mediante el uso de la bacteria E.coli, se requiere del precursor 2-(2’-nitrofenoxi)-acetato de metilo.
En la presente memoria, se estudian las condiciones óptimas de la reacción de síntesis de dicho precursor con el fin de determinar la forma de alcanzar el mayor rendimiento posible. Para ello, se realiza un diseño de experimentos, un posterior tratamiento estadístico de los datos recopilados y se obtiene un modelo matemático que es el que rige la reacción. Se analizan los cambios que provocan en el rendimiento de reacción los siguientes parámetros: concentración de reactivos, tiempo de reacción, temperatura, y atmósfera de reacción.Allelopathy is: “the science that studies processes where secondary metabolites produced by plants, algae, bacteria and fungi and that influences the growth and development of cultivated and biological systems” and where we therefore, include whatever interaction between plants and their environment.
During the last years, a search for new herbicides based on plants secondary metabolites, has been developed. These must be eco-friendly, must have a good degradability, and they also have to be non-toxic for human beings and effective against the increasingly resistance phenomena.
Natural products arise as an attractive source of agrochemical substances, not only because of their structural diversity, but because of their specific biological action and their “a priori” harmless nature towards their environment. We highlight benzohydroxamic acids (secondary metabolites with a (2H)-1,4-benzoxazin-3(4H)-one skeleton)as natural compounds that come from plants and have shown a high activity. They are also one of the larger studied allelochemicals’ group. Within the most interesting ones, we can find D-DIBOA (4-hydroxy-(2H)-1,4-benzoxazin-3-(4H)-one), which presents high phytotoxicity and stability, and also a very good degradability in soil. Also, 6-Cl-D-DIBOA has a high activity and 8-Cl-D-DIBOA has a high selectivity towards different species.
The chemical synthesis of benzohydroxamic acids (benzoxacinones) takes place within two steps. The first one consists of a nucleophilic substitution by using commercial derivatives of 2-nitrophenol products with different substituents in the benzenic ring. The second step consists of a reduction reaction of the aromatic nitro group.
Due to the explosion risk that the second step of the reaction implies (it’s an exothermic heterogeneous catalysis with hydrogen releasing), new alternatives were explored.
The second step can be done by the use of E.coli in a biotransformation, as it was concluded in the Collaborative Project “P06-TEP-01399 (Producción Biotecnológica de Ácidos Benzohidroxámicos Bioactivos)”.
The present work is part of an excellence project granted by “La Junta de Andalucía” during 2014, which general objective is, D-DIBOA biotechnological production by the means of genetically improving Escherichia Coli, as well as the global optimization of the biotransformation process.
Whether at a laboratory scale or for the biotransformation via E.coli to obtain D-DIBOA, the precursor Methyl 2-(2’-nitrophenoxy)acetate, is required.
In the present memory, we try to determine the optimal conditions of the precursor synthesis reaction in order to obtain the best efficiency possible. With this purpose we design an experimental work plan followed by a statistical treatment of the collected data. This way we are able to obtain the mathematical model that rules the reaction. We analyse the yield depending off the variation of the following parameters: reagent’s concentration, reaction time, temperature and reaction’s atmosphere
A cytotoxic and cytostatic gold(III) corrole
We have synthesized and characterized a water-soluble gold(III) corrole (1-Au) that is highly toxic to cisplatin-resistant cancer cells. Relative to its 1-Ga analogue, axial ligands bind only weakly to 1-Au, which likely accounts for its lower affinity for human serum albumin (HSA). We suggest that the cytotoxicity of 1-Au may be related to this lower HSA affinity
One step synthesis of niobium doped titania nanotube arrays to form (N,Nb) co-doped TiO 2 with high visible light photoelectrochemical activity
International audienceThe chemical modification of aligned titanium dioxide nanotube (TiO2-NT) arrays provides new doping possibilities to improve their photoelectrochemical activity under visible light. Niobium doped TiO2-NTs containing up to 15% of Nb in the near-surface region are prepared by a flexible single step procedure using a fluoroniobate complex simultaneously acting as a source of the doping element and fluoride anions required for nanotube formation. This negatively charged complex allows an efficient insertion of Nb in the forming TiO2-NT structure during the anodization process. These nanotube arrays are further modified with nitrogen to achieve (Nb,N) co-doped nanotubes with noticeable visible light photoelectrochemical activity
Large-Volume String Compactifications, Revisited
We reconsider the issue of large-volume compactifications of the heterotic
string in light of the recent discoveries about strongly-coupled string
theories. Our conclusion remains firmly negative with respect to classical
compactifications of the ten-dimensional field theory, albeit for a new reason:
When the internal sixfold becomes large in heterotic units, the theory acquires
an additional threshold at energies much less then the naive Kaluza-Klein
scale. It is this additional threshold that imposes the ultimate limit on the
compactification scale: Any compactification must have M_{Kaluza Klein} >
4*10^7 Gev; for most compactifications, the actual limit is much higher.
(Generically, M_{Kaluza Klein} > alpha_{GUT} M_{Planck} in either SO(32) or
E_8*E_8 heterotic string.)Comment: 46 pages, uses phyzzx.tex macros, no figure
Pensar con el cuerpo: ¿Una política?
"No se puede pensar sin un cierto estado de enardecimiento sexual" Impulsadas por la fecundidad de esta idea de Nietszche venimos recorriendo un trayecto como grupo de pensamiento filosófico desde hace cuatro años. En nuestra producción colectiva nos hacemos eco de aquellos pensadores-Spinoza, Nietszche, Foucault, Deleuze, Agamben y Badiou- que proponen una inversión de la tradición filosófica que excluye al cuerpo del pensamiento. Desde este marco teórico nos proponemos desplegar en estas jornadas interrogantes acerca de la manera en que el cuerpo ?objeto eminente de la biología- deviene factor político, dando surgimiento a la biopolítica. Junto a esta cuestión incluimos paralelamente el problema de las relaciones de poder y el modo de afección sobre los cuerpos y sus potencias colectivas.Eje temático: Representaciones e imaginarios del cuerpo y la culturaDepartamento de Educación Físic
Intuitive Eating Behavior, Diet Quality and Metabolic Health in the Postpartum in Women with Gestational Diabetes
Little is known regarding intuitive eating (IE), diet quality and adherence. We investigated the associations between IE, diet quality and metabolic health after gestational diabetes (GDM), who have an increased diabetes risk. Data from 179 women with GDM from MySweetheart trial (NCT02872974) were analyzed. IE was assessed using the eating for physical rather than emotional reasons (EPR) and reliance on hunger and satiety cues (RHSC) subscales of the French Intuitive Eating Scale-2. Metabolic outcomes included weight, central body fat and insulin resistance. Diet quality was calculated using the Alternative Health Eating Index (AHEI) and compliance with national recommendations was evaluated. Both IE subscales were associated with lower BMI and fat mass (BIA) at 1-year postpartum (all p ≤ 0.034). The EPR subscale inversely correlated with fat mass (DXA) and visceral adipose tissue (both p ≤ 0.028), whereas RHSC with higher insulin sensitivity (Matsuda, p = 0.034). RHSC during pregnancy predicted increased AHEI (p = 0.043) at 1-year postpartum, whilst EPR predicted lower fat mass and insulin resistance (HOMA-IR) (all p ≤ 0.04). In longitudinal analyses, both subscales were associated with increased adherence to dairy and fiber intake recommendations (both p ≤ 0.023). These data suggest IE may be an interesting approach to improve diet quality and metabolic outcomes in women with GDM
Mapping pathological phenotypes in a mouse model of CDKL5 disorder.
open14sihe research was supported by EMBL (E.A. and C.T.G.), the Italian Telethon Foundation (grant GGP09196, T.P. and M.G.; grant GGP10162, E.C., T.P., and M.G.), Epigenomics Flagship Project EPIGEN, MIUR-CNR to T.P., AIRETT onlus (T.P. and M.G.), the International Rett Syndrome Foundation (ISRF, M.G.), and a fellowship from the International Foundation for CDKL5 Research (IFCR) in collaboration with ISRF (E.A.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Mutations in cyclin-dependent kinase-like 5 (CDKL5) cause early-onset epileptic encephalopathy, a neurodevelopmental disorder with similarities to Rett Syndrome. Here we describe the physiological, molecular, and behavioral phenotyping of a Cdkl5 conditional knockout mouse model of CDKL5 disorder. Behavioral analysis of constitutive Cdkl5 knockout mice revealed key features of the human disorder, including limb clasping, hypoactivity, and abnormal eye tracking. Anatomical, physiological, and molecular analysis of the knockout uncovered potential pathological substrates of the disorder, including reduced dendritic arborization of cortical neurons, abnormal electroencephalograph (EEG) responses to convulsant treatment, decreased visual evoked responses (VEPs), and alterations in the Akt/rpS6 signaling pathway. Selective knockout of Cdkl5 in excitatory and inhibitory forebrain neurons allowed us to map the behavioral features of the disorder to separable cell-types. These findings identify physiological and molecular deficits in specific forebrain neuron populations as possible pathological substrates in CDKL5 disorder.openAmendola E;Zhan Y;Mattucci C;Castroflorio E;Calcagno E;Fuchs C;Lonetti G;Silingardi D;Vyssotski AL;Farley D;Ciani E;Pizzorusso T;Giustetto M;Gross CTAmendola E;Zhan Y;Mattucci C;Castroflorio E;Calcagno E;Fuchs C;Lonetti G;Silingardi D;Vyssotski AL;Farley D;Ciani E;Pizzorusso T;Giustetto M;Gross C
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