Search results for "A2"
showing 10 items of 1101 documents
Two-stage anaerobic digestion of tomato, cucumber, common reed and grass silage in leach-bed reactors and upflow anaerobic sludge blanket reactors
2010
Abstract Anaerobic digestion of tomato, cucumber, common reed and grass silage was studied in four separate two-stage reactor configuration consisting of leach bed reactor (LBR) and upflow anaerobic sludge blanket reactor (UASB). LBR studies showed that COD solubilization for cucumber and grass silage was higher (50%) than tomato (35%) and common reed (15%). Results also showed that 31–39% of initial TKN present in tomato and cucumber was solubilized in the leachates and 47–54% of the solubilized TKN was converted to NH4-N. The corresponding values for common reed and grass silage were 38–50% and 18–36%, respectively. Biomethanation of the leachates in UASB reactors resulted in methane yiel…
The effect of organic loading rate and retention time on hydrogen production from a methanogenic CSTR.
2011
Abstract The possibility of shifting a methanogenic process for hydrogen production by changing the process parameters viz., organic loading rate (OLR) and hydraulic retention time (HRT) was evaluated. At first, two parallel semi-continuously fed continuously stirred tank reactors (CSTR) were operated as methanogenic reactors (M1 and M2) for 78 days. Results showed that a methane yield of 198–218 L/kg volatile solids fed (VS fed ) was obtained when fed with grass silage at an OLR of 2 kgVS/m 3 /d and HRT of 30 days. After 78 days of operation, hydrogen production was induced in M2 by increasing the OLR from 2 to 10 kgVS/m 3 /d and shortening the HRT from 30 to 6 days. The highest H 2 yield …
Co-digestion of sewage sludge and sterilized solid slaughterhouse waste: Methane production efficiency and process limitations
2012
The rendering product of Category 2 and 3 Animal By-Products is known as sterilized mass (SM) and it is mainly composed of fat and proteins, making it interesting substrate for anaerobic digestion. Batch and semi-continuous laboratory experiments were carried out to investigate the effect of SM addition in co-digestion with sewage sludge on methane production and possible process limitations. Results showed that SM addition in the feed mixture up to 5% (w/w), corresponding to 68.1% of the organic loading, increased methane production 5.7 times, without any indication of process inhibition. Further increase of SM addition at 7.5% (w/w) caused methane production decrease and volatile solids r…
Activation of bee venom phospholipase A2 through a peptide-enzyme complex
1995
AbstractPhospholipase A2 activation by membrane-bound peptides was investigated in order to understand the role of the membrane-induced conformation on activation, and to examine the occurrence of a peptide-enzyme complex at the lipid/water interface. For the peptides studies, bee venom phospholipase A2 was stimulated regardless of the membrane-bound conformation (α-helix, β-sheet or random coil). Using antisera raised against melittin, we were able to demonstrate the occurrence of a calcium-dependent complex involving the enzyme, phospholipid substrate, and peptide.
Synthesis and Structure-Activity Relationships of Amino Acid Conjugates of Cholanic Acid as Antagonists of the EphA2 Receptor
2013
The Eph–ephrin system plays a critical role in tumor growth and vascular functions during carcinogenesis. We had previously identified cholanic acid as a competitive and reversible EphA2 antagonist able to disrupt EphA2-ephrinA1 interaction and to inhibit EphA2 activation in prostate cancer cells. Herein, we report the synthesis and biological evaluation of a set of cholanic acid derivatives obtained by conjugation of its carboxyl group with a panel of naturally occurring amino acids with the aim to improve EphA2 receptor inhibition. Structure-activity relationships indicate that conjugation of cholanic acid with linear amino acids of small size leads to effective EphA2 antagonists whereas …
Parental socialization: Brazilian adaptation of the ESPA29 Scale
2011
O objetivo deste estudo foi analisar as propriedades psicométricas da versão em português brasileiro da escala de socialização parental ESPA29 (Musitu & García, 2001). Esta escala permite medir os estilos de socialização parental - autoritativo, autoritário, indulgente e negligente - através de duas dimensões independentes da conduta parental, extraídas do uso que os pais fazem das distintas práticas de socialização. Utilizando uma amostra de 2105 adolescentes brasileiros, com idades entre os 10 e os 18 anos, replicou-se a estrutura de dois fatores - Aceitação/Implicação e Severidade/Imposição - que compõem a escala, mediante a análise fatorial exploratória. Para completar o estudo de repli…
Spazio, Rappresentazione, Architettura
2008
El problema de la representación del espacio construido (la arquitectura) no puede prescindir de la concepción de espacio físico que durante siglos el hombre ha formulado.
Planning Research ‘with’ Minorities in Palermo: Negotiating Ethics and Commitments in a Participatory Process
2008
The paper will explore some ethical issues which arise when undertaking research with minorities (ethnic groups, children, poor people) in the context of an uncollaborative planning process, like the Palermo Local Agenda 21. There are important ethical issues that have to be carefully considered when undertaking research with people, particularly when these people are marginalised or excluded by wider society. Here, issues of powerlessness and vulnerability abound. If this is accepted, some questions arise. How are we supposed to consider planning researchers – understood as immersed in the policy process – as moral/political agents, given their political commitments? Here there are both ge…
Computational study of linear carbon chains on gold and silver surfaces
2012
Abstract Density-functional-theory calculations were carried out for hydrogen capped linear carbon chains, polyynes and cumulenes, adsorbed dissociatively on the (1 1 1) and (2 1 1) surfaces of gold and silver. In the studied adsorption reactions, carbon–hydrogen bonds are broken and covalent carbon–metal bonds are created. The adsorption of cumulenes is highly endothermic, whereas the adsorption of polyynes is near thermoneutral. Also, the hydrogenation of adsorbed polyynyl radicals (·C n H) into adsorbed cumulene carbenes (:C n H 2 ) was investigated, which was found to be exothermic on both metals. Vibrational calculations were conducted on the adsorption systems, and the results were co…
Vitruvio y la idea estética del Decorum
2001
El término latino decorum, que Cicerón asimila a la belleza moral, residiendo ésta en lo conveniente o apropiado, tiene sus orígines en el pensamiento estético socrático.