Predicting model training time to optimize distributed machine learning applications

Despite major advances in recent years, the field of Machine Learning continues to face research and technical challenges. Mostly, these stem from big data and streaming data, which require models to be frequently updated or re-trained, at the expense of significant computational resources. One solution is the use of distributed learning algorithms, which can learn in a distributed manner, from distributed datasets. In this paper, we describe CEDEs—a distributed learning system in which models are heterogeneous distributed Ensembles, i.e., complex models constituted by different base models, trained with different and distributed subsets of data. Specifically, we address the issue of predicting the training time of a given model, given its characteristics and the characteristics of the data. Given that the creation of an Ensemble may imply the training of hundreds of base models, information about the predicted duration of each of these individual tasks is paramount for an efficient management of the cluster’s computational resources and for minimizing makespan, i.e., the time it takes to train the whole Ensemble. Results show that the proposed approach is able to predict the training time of Decision Trees with an average error of 0.103 s, and the training time of Neural Networks with an average error of 21.263 s. We also show how results depend significantly on the hyperparameters of the model and on the characteristics of the input data.This work has been supported by national funds through FCT – Fundação para a Ciência e Tecnologia through projects UIDB/04728/2020, EXPL/CCI-COM/0706/2021, and CPCA-IAC/AV/475278/2022

Evaluation of leguminous lectins activities against bacterial biofilm formation

Biofilms are composed by microbial cells that are irreversibly associated with a surface and enclosed in a matrix of polymeric material. Lectins are sugar binding proteins of non immune origin that agglutinate cells and ⁄ or precipitate glycoconjugate molecules. Due to their capacity to bind and recognize specific carbohydrates, lectins can be a potent tool in biofilm studies. The search for potential phytochemicals as anti-biofilm agents has become an active area of research, and these proteins can bind to the bacteria or prevent the interaction with the surface and consequently decrease biofilm formation. Thus, the present work aims to evaluate in vitro the antibacterial activity of plant lectinsfrom Canavalia genus against a panel of bacteria of medical relevance, and to inspect their capacity to interfere on the initial adhesion events and biofilm formation. The assays were carried out using different concentrations of leguminous lectins, isolated from Canavalia ensiformis (ConA), C. maritima (ConM) and C. boliviana (ConBol). The effect of lectins was tested on Klebsiella oxytoca ATCC13182, Pseudomonas aeruginosa ATCC10145, Staphylococcus epidermidis CECT231 and Staphylococcus aureus. The bacterial planktonic growth in the presence of the lectins was determined trough absorbance measurement at 640 nm. Adhesion and biofilm assays were performed in polystyrene plates, and chalenged with the three lectins. The biomass accumulated was quantified using crystal violet staining. The results showed that ConA emerged as the most promising lectin since it clearly reduced the bacterial plankctonic growth, specially of the Gram+ strains, with MIC values ranging between 30 and 125 μg/mL. ConA also disturbed the initial adhesion events of all bacteria and disturbed the biofilm formation ability of the Staphylococcus species for all the concentrations tested. Concerning Gram- bacteria, its biofilm formation ability was only prejudiced with higher concentrations of the lectin. Therefore, the results seem to highlight that the antimicrobial activity of ConA was more noticeable in the disturbance of bacterial adhesion and biofilm formation than impairing planktonic growth. In conclusion, our results show that lectins, an important class of natural products, possess promising antibiofilm activity, suggesting that they may have therapeutic potential for the pharmacological treatment of biofilm-associated infections.IBB-CEB, FCT (PTDC/SAU-ESA/64609/2006) and CAPE

Casbane diterpene as novel and natural antimicrobial agent against biofilm infections

Croton nepetaefolius is a plant native from northeastern Brazil and belongs to Euphorbiaceae family. The essential oil of this plant is widely used in folk medicine from the treatment of gastrointestinal disorders to the use as an antiseptic agent, with an antifungal action scientifically proven. The action of this plant has been extensively explored by the scientific community, being the secondary metabolites, which are responsible for their properties, alkaloids, diterpenes, and triterpenes. The aim of this study was to evaluate the ability of the secondary metabolite, casbane diterpene (CD) (isolated of the species mentioned above), to inhibit microbial growth and biofilm formation of several clinical relevant species (about 15 species among bacteria and fungi). Minimal inhibitory concentration was assessed by the standard technique of microdilution and biofilm inhibition was tested using microtiter plates with biomass quantification by crystal violet staining method. It was found that the CD possessed biocidal and biostatic activity for the majority of the species screened, with the minimal concentration active between 125 and 500 mg/L. Moreover, CD anti-biofilm action was also observed for some of the species. In addition, it was noticed some biofilm formation inhibition even when the planktonic growth was not significantly affected. In conclusion it can be speculated that casbane diterpene shows potential to be a natural tool for the treatment of diseases caused by different infectious microorganisms

Effect of algae and plant lectins on planktonic growth and biofilm formation in clinically relevant bacteria and yeasts

This study aimed to evaluate the abilities of plant and algae lectins to inhibit planktonic growth and biofilm formation in bacteria and yeasts. Initially, ten lectins were tested on Staphylococcus epidermidis, Staphylococcus aureus, Klebsiella oxytoca, Pseudomonas aeruginosa, Candida albicans, and C. tropicalis at concentrations of 31.25 to 250 μg/mL. The lectins from Cratylia floribunda (CFL), Vatairea macrocarpa (VML), Bauhinia bauhinioides (BBL), Bryothamnion seaforthii (BSL), and Hypnea musciformis (HML) showed activities against at least one microorganism. Biofilm formation in the presence of the lectins was also evaluated; after 24 h of incubation with the lectins, the biofilms were analyzed by quantifying the biomass (by crystal violet staining) and by enumerating the viable cells (colony-forming units). The lectins reduced the biofilm biomass and/or the number of viable cells to differing degrees depending on the microorganism tested, demonstrating the different characteristics of the lectins. These findings indicate that the lectins tested in this study may be natural alternative antimicrobial agents; however, further studies are required to better elucidate the functional use of these proteins.This study was supported by the CAPES (Brazil) under the BEX NT 2052/11NT3 Project, by the IBB-CEB and FCT (Portugal), by the European Community Fund FEDER, and by the COMPETE Program under the auspices of the PTDC/SAU-ESA/646091/2006/FCOMP-01-0124-FEDER-007480 Project. Kyria Santiago Nascimento, Alexandre Holanda Sampaio, Benildo Sousa Cavada, and Edson Holanda Teixeira are Senior Fellows of CNPq. Mr. David Martin helped with the English editing of the paper that was also revised by AJE (American Journal Experts)

Avaliação de diferentes polissacarídeos como depressores na flotação aniônica direta de minério fosfático ultrafino / Evaluation of different polysaccharides as depressants in direct anionic flotation of ultrafine phosphate ore

A utilização de materiais de baixo custo, ambientalmente corretos e que garantam a eficiência dos processos industriais vem sendo tema de várias pesquisas. Na flotação, o emprego de materiais mais sustentáveis e de baixo custo, como depressores, pode ser uma alternativa rentável e eficiente tecnologicamente. Nesse contexto, o objetivo do trabalho foi utilizar um resíduo amiláceo como depressor na flotação de minério fosfático, comparando os resultados obtidos com 5 (cinco) amidos comerciais de diferentes origens botânicas. Ensaios de flotação, utilizando-se 6 (seis) amostras diferentes (A1 a A6), foram realizados em duplicata. A amostra A5 (resíduo), produziu um concentrado com cerca de 66,6% de recuperação metalúrgica, enquanto as amostras A3 e A6; 62,9% e 49,2%, respectivamente. Os teores de P2O5 obtidos para as amostras mencionadas ficaram em torno de 27,9%; 28,1% e 26,6%, respectivamente. Após análise estatística (ANOVA), verificou-se que não houve variação significativa ao nível de 5%, para teor de P2O5 e recuperação metalúrgica, com exceção da amostra A6, que apresentou os menores valores para os parâmetros citados. Os resultados encontrados abrem novas possibilidades para utilização de resíduos na flotação, uma vez que podem ser utilizados diretamente no processo de gelatinização, sem nenhum tipo de tratamento prévio ou modificações químicas

Prophylactic outcomes of casbane diterpene in Candida albicans and Candida glabrata biofilms

Biofilms are surface associated communities of microorganisms embedded within a self-produced extracellular matrix and adhered on inert and biotic surfaces. These biological consortia are considered the most prevalent growth form of microorganisms. Biofilm formation is a potent virulence factor for a number of Candida species, as it confers significant tolerance to antimicrobial therapy, primarily by limiting the penetration of substances through the biofilm matrix. Casbane Diterpenes (CD) belongs to the class of diterpenoids isolated from few species of plants from Euphorbiaceae family with important anticancer and antibacterial activities. So, the goal of this study was to assess the antibiofilm effect of a Casbane Diterpene isolated from the stalks of Croton nepetaefolius against Candida albicans and Candida glabrata. Biofilms were developed within the 96- well microtiterplates in the presence of the CD. After 24 hours of growth, 100 μL of cells suspensions (1 x 106 cells ml-1 in Nutrient Broth) and 100 μL of solution of CD (500 - 31.5 μg/mL) were pipetted into each well and incubated for 24 h at 37ºC in an orbital shaker at 120 rpm. Biofilms formation was characterized by total biomass, through crystal violet (CV), and number of viable cells, expressed as log CFU per cm2. CD showed to be able to reduce the biofilm formation of C. albicans and C. glabrata. CD reduced C. albicans biomass in 82, 64, 57 and 27 % at the concentrations of 500, 250, 125 and 62.5 μg/mL, respectively. C. glabrata biomass was reduced in 68 and 26 % at 500 and 250 μg/mL. Regarding the number of viable cells embedded in the yeast biofilms, CD at 500 and 250 μg/mL reduced 2 and 1 log of C. albicans biofilm CFUs, and 2.5 and 1 log for C. glabrata, respectively. Regarding the high resistance and recalcitrance of Candida biofilms to the traditional therapies, CD emerges as a good prophylactic alternative to be used alone or in combination with other traditional drugs

Mapeamento de Informações Tecnológicas em Documentos de Patente: uso da borra de café na produção de biocombustíveis

The study aimed to map technological information contained in patent documents related to the use of coffee grounds as a raw material in the production of biofuels. The methodology of the work consisted of searching for patent documents in Derwent Innovations Index, National Institute of Industrial Property (INPI) and LATIPAT-ESPACENET, using keywords and codes of International Patent Classification (IPC) and Cooperative Patent Classification (CPC), previously identified in the bibliographic and patent review. The results indicated concentration of technologies in class C10L-005 in solid state; reveal South Korea, Japan and the US as markets in which there is greater commercial interest; suggest that there is no technological maturity at the industrial level yet; and show that biofuel development in Brazil has been driven by government policies.O estudo teve por objetivo mapear informações tecnológicas contidas em documentos de patente relacionadas ao aproveitamento da borra de café como matéria-prima na produção de biocombustíveis. A metodologia do trabalho consistiu na busca de documentos de patente no Derwent Innovations Index, Instituto Nacional da Propriedade Industrial (INPI) e LATIPAT-ESPACENET, utilizando palavras-chave e códigos de Classificação Internacional de Patentes (IPC) e Classificação Cooperativa de Patentes (CPC), previamente identificados na revisão bibliográfica e patentária. Os resultados indicaram concentração das tecnologias na classe C10L-005 em estado sólido; revelam a Coreia do Sul, Japão e EUA como mercados em que há maior interesse comercial; sugerem que ainda não há maturidade tecnológica em âmbito industrial; e mostram que o desenvolvimento de biocombustível no Brasil tem sido impulsionado pelas políticas de governo

Essential Oils as an Innovative Approach against Biofilm of Multidrug-Resistant <em>Staphylococcus aureus</em>

Staphylococcus aureus is one of the most common pathogens that cause recurrent, chronic, and biofilm-related diseases. Biofilms are the major form of bacterial structures capable of secreting polysaccharides that provide intrinsic protection against environmental stress like high concentrations of antibiotics. This, along with the emergence of multidrug-resistant strains, has made S. aureus infections a worldwide problem as a result of the inefficiency of the conventional medications. Plant essential oils (EOs) are an important source for drug discovery and pharmaceutical development due to their diverse biological activities, such as antimicrobial agents. The EOs’ microbicide action is extensively reported at the scientific literature and frequently associated with bioactive molecules, such as aldehydes and terpenes. However, the ability of some EOs to inhibit biofilm formation has been poorly explored and it is still unclear how they could be applied in specific treatments against well-known infections. Therefore, this chapter will address virulence factors and biofilm formation of S. aureus, as well as bioprospecting of essential oil as a promising source in the search for new bioactive compounds employed in the fight against this microorganism