152 research outputs found
Principles and design scenarios for sustainable urban food logistics
Food and nutrition systems are linked to all Sustainable Development Goals (SDGs), which makes their transition toward social-ecological behavior patterns crucial for an overarching sustainability transformation. The perspective of (urban) logistics is of special interest. It couples the production and consumption physically and virtually. In this context, we shed light on the design of the turnover point of food in urban areas from the supply chain toward consumers and contribute to an overarching systemic perspective toward establishing a sustainable multilevel food system. We describe current patterns in urban food systems and propose several principles for sustainable design of (urban) food systems based on concepts such as (regional) collaboration and food literacy. Using these principles, we provide four design scenarios that concretely imagine future urban food consumption and production patterns titled "slow stock supply service," "deliver into the daily walk," "central district food depot," "super food action place." With this work we provide a starting for reflecting whether certain combinations of principles actually lead to patterns of daily life that are feasible, acceptable, or desirable. Moreover, we provide an initial qualitative assessment to stimulate further research that explores scenario pathways and incorporates additional indicators regarding the impact on social-ecological. We open up various research questions with regard to the overarching question of how urban food logistics should be designed to be consistent with the SDGs
Retinoid isomerase inhibitors impair but do not block mammalian cone photoreceptor function
Visual function in vertebrates critically depends on the continuous regeneration of visual pigments in rod and cone photoreceptors. RPE65 is a well-established retinoid isomerase in the pigment epithelium that regenerates rhodopsin during the rod visual cycle; however, its contribution to the regeneration of cone pigments remains obscure. In this study, we use potent and selective RPE65 inhibitors in rod- and cone-dominant animal models to discern the role of this enzyme in cone-mediated vision. We confirm that retinylamine and emixustat-family compounds selectively inhibit RPE65 over DES1, the putative retinoid isomerase of the intraretinal visual cycle. In vivo and ex vivo electroretinography experiments in Gnat1-/- mice demonstrate that acute administration of RPE65 inhibitors after a bleach suppresses the late, slow phase of cone dark adaptation without affecting the initial rapid portion, which reflects intraretinal visual cycle function. Acute administration of these compounds does not affect the light sensitivity of cone photoreceptors in mice during extended exposure to background light, but does slow all phases of subsequent dark recovery. We also show that cone function is only partially suppressed in cone-dominant ground squirrels and wild-type mice by multiday administration of an RPE65 inhibitor despite profound blockade of RPE65 activity. Complementary experiments in these animal models using the DES1 inhibitor fenretinide show more modest effects on cone recovery. Collectively, these studies demonstrate a role for continuous RPE65 activity in mammalian cone pigment regeneration and provide further evidence for RPE65-independent regeneration mechanisms
[Work in progress] Scalable, out-of-the box segmentation of individual particles from mineral samples acquired with micro CT
Minerals are indispensable for a functioning modern society. Yet, their
supply is limited causing a need for optimizing their exploration and
extraction both from ores and recyclable materials. Typically, these processes
must be meticulously adapted to the precise properties of the processed
particles, an extensive characterization of their shapes, appearances as well
as the overall material composition. Current approaches perform this analysis
based on bulk segmentation and characterization of particles imaged with a
micro CT, and rely on rudimentary postprocessing techniques to separate
touching particles. However, due to their inability to reliably perform this
separation as well as the need to retrain or reconfigure methods for each new
image, these approaches leave untapped potential to be leveraged. Here, we
propose ParticleSeg3D, an instance segmentation method that is able to extract
individual particles from large micro CT images taken from mineral samples
embedded in an epoxy matrix. Our approach is based on the powerful nnU-Net
framework, introduces a particle size normalization, makes use of a border-core
representation to enable instance segmentation and is trained with a large
dataset containing particles of numerous different materials and minerals. We
demonstrate that ParticleSeg3D can be applied out-of-the box to a large variety
of particle types, including materials and appearances that have not been part
of the training set. Thus, no further manual annotations and retraining are
required when applying the method to new mineral samples, enabling
substantially higher scalability of experiments than existing methods. Our code
and dataset are made publicly available
Ubistatins Inhibit Proteasome-Dependent Degradation by Binding the Ubiquitin Chain
To identify previously unknown small molecules that inhibit cell cycle machinery, we performed a chemical genetic screen in Xenopus extracts. One class of inhibitors, termed ubistatins, blocked cell cycle progression by inhibiting cyclin B proteolysis and inhibited degradation of ubiquitinated Sic1 by purified proteasomes. Ubistatins blocked the binding of ubiquitinated substrates to the proteasome by targeting the ubiquitin-ubiquitin interface of Lys^(48)-linked chains. The same interface is recognized by ubiquitin-chain receptors of the proteasome, indicating that ubistatins act by disrupting a critical protein-protein interaction in the ubiquitin-proteasome system
RECUPERAÇÃO DE TITÂNIO E ALUMÍNIO A PARTIR DE UM SUBPRODUTO DE CATÁLISE DE UMA PLANTA PETROQUÍMICA
Indústrias do setor metal-mecânico, químico e petroquímico geram mensalmente grandes volumes deresíduos sólidos, contendo, entre outros poluidores, metais pesados tais como cobre, níquel, titânio, alumínioe cádmio. Convencionalmente, estes rejeitos industriais têm sido depositados de forma cumulativa, ematerros (apropriados ou não) ou simplesmente armazenados em tonéis. A deposição desses sólidos geralmentenão segue os padrões exigidos legalmente, constituindo-se em um grave problema ao ecossistema.Nesse contexto, avaliar alternativas com o objetivo de evitar e/ou minimizar a produção de rejeitos ouainda transformá-los em matérias-primas para outros processos de fabricação, torna-se uma necessidadecrescente ao setor produtivo, que procura aliar eficiência com baixo custo. A primeira parte do presenteestudo apresenta alternativas de separação dos principais constituintes de rejeitos industriais que contenhampredominantemente alumínio e titânio. O mesmo fundamenta-se na obtenção de duas frações demaior valor agregado através de uma tecnologia econômica e tecnicamente viável para reciclagem deresíduos ricos nestes metais.Palavras-chave: resíduo sólido, reciclagem, tecnologias de segregação, lixiviaçã
Estudo de aplicação de um resíduo líquido industrial à base de alumínio como reagente coagulante
O presente projeto tem o objetivo de estudar a viabilidade de utilização de um resíduo proveniente deprocesso petroquímico como reagente coagulante em processos de tratamento de efluentes líquidos industriaiscontendo íons dissolvidos. Como metodologia experimental, foram realizados ensaios em Teste deJarros, com o objetivo de verificar as condições ótimas (concentração, pH, remoção de íons) de aplicaçãodo subproduto (resíduo a base de alumínio e sódio) no processo de coagulação em comparação a reagentesutilizados convencionalmente. Para os ensaios experimentais foram utilizadas amostras de efluentes de umcurtume de Estância Velha (Rio Grande do Sul), provenientes das etapas de recurtimento e piquelagem.Foram avaliados o volume de lodo formado e a eficiência na remoção de cromo e alumínio do produtoclarificado. A utilização do subproduto mostrou ser eficiente, atingindo índice de remoção superior a 90%de cromo (concentração residul de 0,2 mg/L). Os experimentos realizados indicam que o reaproveitamento deste resíduo apresenta potencial tecnológico aplicado ao tratamento de efluentes líquidos industriais,considerando igualmente os aspectos ambientais e econômicos.Palavras-chave: remoção, coagulação, cromo, subproduto industrial
A small molecule agonist of EphA2 receptor tyrosine kinase inhibits tumor cell migration in vitro and prostate cancer metastasis in vivo
10.1371/journal.pone.0042120PLoS ONE78
Temperature Dependence of Backbone Dynamics in Human Ileal Bile Acid-Binding Protein: Implications for the Mechanism of Ligand Binding
Human ileal bile acid-binding protein (I-BABP), a member of the family of intracellular lipid binding proteins plays a key role in the cellular trafficking and metabolic regulation of bile salts. The protein has two internal and, according to a recent study, an additional superficial binding site and binds di- and trihydroxy bile salts with positive cooperativity and a high degree of site-selectivity. Previously, in the apo form, we have identified an extensive network of conformational fluctuations on the millisecond time scale, which cease upon ligation. Additionally, ligand binding at room temperature was found to be accompanied by a slight rigidification of picosecond-nanosecond (ps-ns) backbone flexibility. In the current study, temperature-dependent N-15 NMR spin relaxation measurements were used to gain more insight into the role of dynamics in human I-BABP-bile salt recognition. According to our analysis, residues sensing a conformational exchange in the apo state can be grouped into two clusters with slightly different exchange rates. The entropy-enthalpy compensation observed for both clusters suggests a disorder-order transition between a ground and a sparsely populated higher energy state in the absence of ligands. Analysis of the faster, ps-ns motion of N-15-H-1 bond vectors indicates an unusual nonlinear temperature-dependence for both ligation states. Intriguingly, while bile salt binding results in a more uniform response to temperature change throughout the protein, the temperature derivative of the generalized order parameter shows different responses to temperature increase for the two forms of the protein in the investigated temperature range. Analysis of both slow and fast motions in human I-BABP indicates largely different energy landscapes for the apo and halo states suggesting that optimization of binding interactions might be achieved by altering the dynamic behavior of specific segments in the protein
USO DE BIOREATORES SEQÜENCIAIS EM BATELADA COM LEITOS DE ADSORÇÃO PARA GERAÇÃO DE GÁS. PARTE I.
Grande parte dos resíduos dispostos em aterros sanitários são nocivos à saúde e ao meio ambiente,contendo pesticidas organoclorados, metais pesados de baterias e peças eletrônicas, solventes orgânicostintas. Esses resíduos podem favorecer a formação de um ambiente anóxico em presença de nitrato,ferro e sulfato, permitindo que outros organismos tornem-se competitivos na metanogênese para umsubstrato reduzido. Assim, sistemas de reatores seqüenciais em batelada (bioreatores) consistem emum grande potencial de pesquisa para a aplicação como em aterros sanitários em série. O objetivo geraldeste projeto é a pesquisa e desenvolvimento processos integrados para a produção de energia a partirde resíduos dispostos em aterro sanitários, considerando as condições ambientais do Brasil. O presenteestudo apresenta a montagem experimental do sistema de bioreatores utilizado para desenvolvimentoda pesquisa, que visa simular uma coluna de lixo de um aterro sanitário, no qual o chorume gerado érecirculado para o sistema, com adição de lodo anaeróbio. Este estudo envolve a coleta e a caracterizaçãodo resíduo orgânico e inorgânico utilizado, controle de pH do chorume e do lodo anaeróbio e monitoramento da geração de gás (CH4 e CO2). Os resultados preliminares são apresentados emtermos do desenvolvimento dos parâmetros químicos e operacionais do processo em um primeiro estágiodo mesmo com duração de 3 a 6 meses.Palavras-chave: resíduos sólidos domésticos, sistema anaeróbio, biodegradação, otimizaçã
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