1,316 research outputs found
Incentivized Collaboration in Active Learning
No full textIn collaborative active learning, where multiple agents try to learn labels from a common hypothesis, we introduce an innovative framework for incentivized collaboration. Here, rational agents aim to obtain labels for their data sets while keeping label complexity at a minimum. We focus on designing (strict) individually rational (IR) collaboration protocols, ensuring that agents cannot reduce their expected label complexity by acting individually. We first show that given any optimal active learning algorithm, the collaboration protocol that runs the algorithm as is over the entire data is already IR. However, computing the optimal algorithm is NP-hard. We therefore provide collaboration protocols that achieve (strict) IR and are comparable with the best known tractable approximation algorithm in terms of label complexity
The rising of “Modern Actinobacteria” era
No full textThe term “Modern Actinobacteria” (MOD-ACTINO) was coined by a Malaysian Scientist Dr. Lee Learn-Han, who has great expertise and experience in the field of actinobacteria research. MOD-ACTINO is defined as a group of actinobacteria capable of producing compounds that can be explored for modern applications such as development of new drugs and cosmeceutics. MOD-ACTINO members consist of already identified or novel actinobacteria isolated from special environments: mangrove, desert, lake, hot spring, cave, mountain, Arctic and Antarctic regions. These actinobac-teria are valuable sources for various industries which can contribute directly/indirectly towards the improvement in many aspects of our lives.</p
Malaysia’s breakthrough in modern actinobacteria (MOD-ACTINO) drug discovery research
No full textActinobacteria are well-known producers of metabolites with medicinal value. The application of actinobacterial compounds has been expanded to other fields, including agriculture, aquaculture, and cosmeceutical. With this, the term “Modern Actinobacteria” (MOD-ACTINO) was first coined by a Malaysian researcher, Associate Professor Dr. Lee Learn Han, to define actinobacteria with modern applications. The present review aims to highlight the MOD-ACTINO research achievements in Malaysia. The Malaysian MOD-ACTINO strains are capable of exerting a wide range of bioactivities such as antimicrobial/anti-MRSA, anticancer, antioxidant, antifungal, and antimalarial. Research on MOD-ACTINO is highly encouraged to harness the benefits of actinobacteria and unravel important metabolites for various applications.</p
Actinobacteria: Prolific Producers of Bioactive Metabolites
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
COVID-19 pandemic : lessons from Lee Kuan Yew
No full textSingapore’s founding Prime Minister Lee Kuan Yew faced many crises in his lifetime, regional and global. Were he alive, he would have a lot to say about the present COVID-19 pandemic and how to deal with it. What lessons can Singapore and the rest of the world learn from his experience?Published versio
Actinobacteria: Prolific Producers of Bioactive Metabolites
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Deep residual neural network for predicting aerodynamic coefficient changes with ablation
No full textData-driven methods for predicting aerodynamic coefficients of arbitrary shapes have received considerable attention due to their flexibility and scalability. This paper introduces a deep-learning framework based on a deep residual neural network and K-fold cross-validation for fast and accurate prediction of aerodynamic coefficients of a three-dimensional cone with shape changes due to ablation. The proposed neural network model is trained to learn the underlying relationship between shape transformations and the corresponding changes in aerodynamic coefficients. The shape transformations due to ablation are expressed as the difference between the nominal and ablated cones, measured in units of mesh coordinates. Multiple (K) models constructed based on the training process are combined to reduce the prediction variance effectively. The resulting ensemble model shows an improved prediction performance for various aerodynamic coefficients. To validate our methodology, we compare our model with the generic Multilayer Perceptron (MLP) with a varying number of neurons and the Gaussian process (GP) regression. The test results indicate that the proposed model predicts the aerodynamic coefficients more accurately than the baseline model (MLP/GP), indicating an improved generalization to unseen data. © 2023 Elsevier Masson SAS
Optimization of torrefaction conditions on antioxidant activity of prickly pear seeds extract using response surface methodology and chemometric analysis
No full textThe prickly pear (Opuntia ficus-indica L., Cactaceae) seeds can be used as an alternative food product by the torrefaction process. Torrefaction is a pre-treatment process of biomass into solid fuel within a temperature range of 60–200 °C. This study aimed to investigate the effect of torrefaction parameters on the antioxidant potential of prickly pear seeds, which is considered a food by-product, by using the Central Composite Design approach (CCD).The best torrefaction parameters found to have the optimal phytochemical contents were: 200 °C and 50 min with 104.86 ± 1.94 GAE/g extract for Total Phenolic Content (TPC), 200 °C and 50 min with 81.23 ± 0.90 mg QE/g extract for Total Flavonoid Content (TFC), 200 °C and 50 min with IC50 = 90.66 ± 2.09 μg/ml for free radical scavenging activity (DPPH assay), 200 °C and 50 min with IC50 = 124.9 ± 4 μg/ml for radical cation total antioxidant capacity (ABTS assay). Our results demonstrated an increase of antioxidant activities with the increase of torrefaction parameters. Therefore, torrefaction has proven to be a value-added process to exploit prickly pear seed biomass and use it as a source of antioxidant food additives
Molecular Profiling and Antibiotic Resistance of Salmonella Enterica Subsp. Enterica Isolated from Indigenous Ulam and Poultry Meat
No full textSalmonella enterica subsp. enterica formed the major group that represents nearly
60% of the salmonellae. Salmonella organisms emerged as a public health problem
in many countries as salmonellosis has become the most prevalent foodborne disease
worldwide. It has been estimated that approximately 1.4 million cases were reported
annually in the developed nations such as USA. In Malaysia, of 8,640 cases of food
poisoning reported by the Ministry of Health for the year 1999, 811 (9.4%) were due
to Salmonella. The purpose of this study was to characterize and study Salmonella
enterica subsp. enterica (S. enterica) using multiple antimicrobial resistance and
several molecular typing methods including plasmid profiling, PCR-RFLP, RAPD,
ERIC-PCR and Multiplex PCR on antibiotic resistant gene. The isolate were
recovered from poultry meat (55), four types of indigenous vegetables namely
‘selom’ (Oenanthe stolonifera) (59), ‘pegaga’ (Centella asiatica) (20), ‘kesum’
(Polygonum minus) (41), ‘kangkong’ (Ipomoea aquatica) (14) and processed food
(11).Genomic DNA of the 200 S. enterica isolates belonging to 43 different serovars were
recovered from poultry meat, various indigenous vegetables and processed food was
confirmed by specific and duplex PCR targeting the iroB gene that yielded 443 bp
and 606 bp amplicons. The PCR amplification of iroB gene is a rapid and reliable
method for distinguishing between S. enterica and other bacterial species.
Plasmids of S. enterica varied in sizes from 2 to more than 200 kb. Despite limited
knowledge on their function, their presence is frequently used for strain
differentiation in epidemiological studies. Plasmid profiling on the 200 S. enterica
isolates demonstrated high discriminatory capability for serovars differentiation in
this study that was clustered into 70 groups based on the number and pattern of the
bands.
One of the amplification based techniques used in this study for molecular
characterization was PCR-RFLP that incorporated PCR of iroB1, iroB2 and
restriction digest with BglII and AluI to determine the relatedness of bacterial strains.
Results obtained showed that PCR-RFLP has excellent typeablity but low
discriminatory power due to its inability to produce different banding patterns.
ERIC sequences are short, highly conserved 126 bp non-coding regions found in the
Enterobacteriaceae. Its location in bacterial genomes allows discrimination at the
genus, species and serovars levels. RAPD is an amplification-based technique using
arbitrary primers to detect changes in the DNA sequence at the sites in the genome
and enable the discrimination of samples according to sources and serovars.
Dendrogram of RAPD and ERIC-PCR were analyzed and comparisons made using BioNumerics gel analysis software (Applied Maths, Kortrijk, Belgium). Among the
200 isolates of S. enterica, RAPD with arbitrary primers OPAR02, OPAR17 and
OPAR19 generated 47 clusters and 13 single isolates whereas ERIC-PCR with
primers ERIC-1 and ERIC-2 produced 46 clusters and 12 single isolates at 60%
similarity level with discriminatory index (D) of 0.9726 and 0.9606 respectively.
Composite analysis of RAPD and ERIC-PCR profiling simultaneously produced 50
clusters and 18 single isolates at 60% similarity level with highest discriminatory
index of 0.9824. These results demonstrated that composite analysis of RAPD
(OPAR02, OPAR17 and OPAR19) together with ERIC-PCR are a better tool for
differentiation and characterization of S. enterica as compared to a single method
approach.
The multiplex PCR targeted three different antibiotic resistance genes that was used
to detect TEM, PSE-1 and cmlA/tetR genes segment encoding resistance towards
ampicillin, chloramphenicol and tetracycline, respectively which could reduce labour
and cost in analysis of a large number of isolates.
Subsequently antimicrobial resistance was performed using disc diffusion method
with a selection of 13 different antimicrobial agents. Total of 66 profiles were
generated and multiple antimicrobial resistance (MAR) analysis indicated poultry
meat still remains as the main reservoir for multi drug resistant Salmonella. In
contrast, six isolates from the indigenous vegetables showed the highest MAR index
(0.69). This might be due to animal waste fertilizer, irrigation water, contaminated
container and improper handling of food by human that contributed to be the sources
of Salmonella contamination of vegetables. Further investigations need to be conducted to determine if Salmonella isolates in recovered from indigenous
vegetables were gaining more antimicrobial resistance. The characterization of MAR
enabled the determination of antimicrobial patterns and trends in Salmonella from
poultry meat and indigenous vegetables in Malaysia.
As a conclusion, the results from this study could provide valuable information on
the epidemiology and drug resistance trends of S. enterica, and hence contribute
towards better surveillance and infection control measures as well as improved
public health policy
Novel actinobacteria discovery and biosystematics of bacteria from antarctic soils on Barrientos Island
No full textThe Antarctic, one of the most poorly explored areas on Earth has emerged as a prospective region for the discovery of novel bacteria and bioactive metabolites. A total
of 17 soil samples were collected from different areas of Barrientos Island to determine the distribution of bacteria in the soil and the potential of soil bacteria (particularly
Actinobacteria) in producing bioactive secondary metabolites. The Biolog EcoPlate system and RAPD both demonstrated that soils with different types of rookery and
characteristics could affect the soil DNA sequences and soil microbial diversity. The PCR-DGGE used to study the diversity of bacteria, especially Actinobacteria
successfully displayed the diverse types of bacteria found within the soil and also provided estimations of their densities. A total of 96 bacterial strains were isolated using 12 different types of isolation media, 39 strains from phylum Actinobacteria and 57 strains from phyum Proteobacteria. Tests for bioactive secondary metabolites were performed and a total of 15 and 14 isolates of Actinobacteria and Proteobacteria were bioactive. The novel strain, 39T was fully characterized by using the polyphasic
approach and results showed that it have many differences from the other genera in the family Dermacoccaceae on the basis of phylogenetic, chemotaxonomic, phenotypic and
signature nucleotide pattern of the 16S rRNA gene. Therefore, it is suggested that strain 39T be classified as a novel genus in the family Dermacoccaceae, as Barrientosiimonas gen. nov., the type species of which is Barrientosiimonas humi gen. nov., sp. nov. It is
evident from this study that the soil of Barrientos Island is a rich source of taxonomically diverse bacteria, especially Actinobacteria. The wide distribution of these
bacteria in the Antarctic implies that they are endemic and therefore the bio-prospecting of soil bacteria from a wide range of geographic locations like the Antarctic regions
would be of great benefit
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