ABSTRACT
Clustering analysis is an unsupervised learning method, which has applications across many fields such as pattern recognition, machine learning, information security, and image segmentation. The density-based method, as one of the various clustering algorithms, has achieved good performance. However, it works poor in dealing with multidensity and complex-shaped datasets. Moreover, the result of this method depends heavily on the parameters we input. Thus, we propose a novel clustering algorithm (called the MST-DC) in this paper, which is based on the density core. Firstly, we employ the reverse nearest neighbors to extract core objects. Secondly, we use the minimum spanning tree algorithm to cluster the core objects. Finally, the remaining objects are assigned to the cluster to which their nearest core object belongs. The experimental results on several synthetic and real-world datasets show the superiority of the MST-DC to Kmeans, DBSCAN, DPC, DCore, SNNDPC, and LDP-MST.
Subject(s)
Algorithms , Cluster AnalysisABSTRACT
A Gram-stain-positive, aerobic, non-motile and coccoid-shaped bacterium, designated XNB-1T, was isolated from farmland soil in Taian, Shandong province, China. Strain XNB-1T contained iso-C15â:â0 and iso-C16â:â0 as the predominant fatty acids. The diagnostic diamino acid of the peptidoglycan was ornithine, and the interpeptide bridge was l-OrnâGly(1, 2)âd-Glu. The polar lipid profile of strain XNB-1T consisted of diphosphatidylglycerol, phosphatidylglycerol, an unidentified phosphoglycolipid and three unidentified phospholipids. The predominant menaquinone of strain XNB-1T was MK-8(H4) and the DNA G+C content was 70.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain XNB-1T belonged to the genus Ornithinicoccus, and shared the highest similarity with Ornithinicoccus hortensis HKI 0125T (96.0â%), followed by Ornithinicoccus halotolerans EGI 80423T (95.5â%). Genome-based analysis of average nucleotide identity of strain XNB-1T with O. hortensis HKI 0125T and O. halotolerans EGI 80423T yielded values of 73.1 and 73.3â%, respectively, while the digital DNA-DNA hybridization values were 19.5 and 19.9â%, respectively. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain XNB-1T is considered to represent a novel species of the genus Ornithinicoccus, for which the name Ornithinicoccus soli sp. nov. is proposed. The type strain is XNB-1T (=CCTCC AB 2019099T=KCTC 49259T).
Subject(s)
Actinobacteria/classification , Farms , Phylogeny , Soil Microbiology , Actinobacteria/isolation & purification , Bacterial Typing Techniques , Base Composition , China , DNA, Bacterial/genetics , Fatty Acids/chemistry , Nucleic Acid Hybridization , Peptidoglycan/chemistry , Phospholipids/chemistry , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Vitamin K 2/analogs & derivatives , Vitamin K 2/chemistryABSTRACT
A Gram-stain-positive, strictly aerobic, non-motile, non-spore-forming and rod-shaped bacterium, designated as strain G-1T, was isolated from farmland soil sampled in in Fuyang, Anhui Province, PR China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain G-1T was closely related to Cumulibacter manganitolerans 2-36T (97.7â% similarity). Strain G-1T contained iso-C16â:â0, C17â:â1ω6c, iso-C15â:â0 and iso-C14â:â0 as the predominant fatty acids. The polar lipids of strain G-1T were diphosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified lipid and two unidentified glycolipids. The predominant respiratory quinone of strain G-1T was MK-9(H4). The cell wall contained meso-diaminopimelic acid as the diagnostic diamino acid. The G+C content of the genomic DNA based on genome calculations was 64.2 mol%. Average nucleotide identity and the digital DNA-DNA hybridization values for the draft genomes between strain G-1T and strain 2-36T were 75.7 and 20.2 %, respectively. On the basis of phenotypic and phylogenetic data, strain G-1T is considered to represent a novel species of the genus Cumulibacter, for which the name Cumulibacter soli sp. nov. is proposed. The type strain is G-1T (=CCTCC AB2019021T=KCTC 49258T).
Subject(s)
Actinobacteria/classification , Farms , Phylogeny , Soil Microbiology , Actinobacteria/isolation & purification , Bacterial Typing Techniques , Base Composition , China , DNA, Bacterial/genetics , Diaminopimelic Acid/chemistry , Fatty Acids/chemistry , Glycolipids/chemistry , Nucleic Acid Hybridization , Phospholipids/chemistry , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Vitamin K 2/analogs & derivatives , Vitamin K 2/chemistryABSTRACT
As zwitterionic polymers show great promise in drug delivery, hyaluronic acid (HA) was deacetylated and grafted with dodecylamine to prepare a pH-sensitive zwitterionic polymer dHAD used as a carrier for antitumor drugs. The polymer was negatively charged at pH 7.4 and became positive at pH 6.2. In vitro delivery of DOX against MCF-7 cells showed that the blank micelle dHAD had low cytotoxicity and the dHAD-DOX micelles could greatly prohibit the growth of the MCF-7 cells. In addition, the dHAD-DOX micelles had higher cellular uptake, indicating that the micelles were rapidly internalized into the cells via CD44 receptor-mediated endocytosis. The in vivo delivery of DOX to tumor-bearing mice confirmed that the dHAD-DOX micelles greatly inhibited the tumor growth and significantly reduced systemic toxicity of DOX. These results demonstrated that biocompatible pH-responsive zwitterionic dHAD micelles are promising carriers for the delivery of DOX.
