McTwo: a two-step feature selection algorithm based on maximal information coefficient.

BACKGROUND: High-throughput bio-OMIC technologies are producing high-dimension data from bio-samples at an ever increasing rate, whereas the training sample number in a traditional experiment remains small due to various difficulties. This "large p, small n" paradigm in the area of biomedical "big data" may be at least partly solved by feature selection algorithms, which select only features significantly associated with phenotypes. Feature selection is an NP-hard problem. Due to the exponentially increased time requirement for finding the globally optimal solution, all the existing feature selection algorithms employ heuristic rules to find locally optimal solutions, and their solutions achieve different performances on different datasets. RESULTS: This work describes a feature selection algorithm based on a recently published correlation measurement, Maximal Information Coefficient (MIC). The proposed algorithm, McTwo, aims to select features associated with phenotypes, independently of each other, and achieving high classification performance of the nearest neighbor algorithm. Based on the comparative study of 17 datasets, McTwo performs about as well as or better than existing algorithms, with significantly reduced numbers of selected features. The features selected by McTwo also appear to have particular biomedical relevance to the phenotypes from the literature. CONCLUSION: McTwo selects a feature subset with very good classification performance, as well as a small feature number. So McTwo may represent a complementary feature selection algorithm for the high-dimensional biomedical datasets.

Phase-change composite filled natural nanotubes in hydrogel promote wound healing under photothermally triggered drug release.

It is of great importance to treat a bacterial-infected wound by a smart dressing capable of delivering antibiotics in a smart manner without causing drug resistance. The construction of smart release nanocontainers responsive to near-infrared (NIR) laser irradiation in an on-demand and stepwise way is a promising strategy for avoiding the emergence of multidrug-resistant bacteria. Here, we develop a hydrogel composite made of alginate and nanotubes with an efficient NIR-triggered release of rifampicin and outstanding antibacterial ability. This composite hydrogel is prepared through co-encapsulating antibacterial drug (rifampicin), NIR-absorbing dye (indocyanine green), and phase-change materials (a eutectic mixture of fatty acids) into halloysite nanotubes, followed by incorporation into alginate hydrogels, allowing the in-situ gelation at room temperature and maintaining the integrity of drug-loaded nanotubes. Among them, the eutectic mixture with a melting point of 39 °C serves as the biocompatible phase-change material to facilitate the NIR-triggered drug release. The resultant phase-change material gated-nanotubes exhibit a prominent photothermal efficiency with multistep drug release under laser irradiation. In an in vitro assay, composite hydrogel provides good antibacterial potency against Staphylococcus aureus, one of the most prevalent microorganisms of dangerous gas gangrene. A bacterial-infected rat full-thickness wound model demonstrates that the NIR-responsive composite hydrogel inhibits the bacteria colonization and suppresses the inflammatory response caused by bacteria, promoting angiogenesis and collagen deposition to accelerate wound regeneration. The NIR-responsive composite hydrogel has a great potential as an antibacterial wound dressing functionalized with controlled multistep treatment of the infected sites.

Integrating Inflammation-Responsive Prodrug with Electrospun Nanofibers for Anti-Inflammation Application.

Chronic inflammation plays a side effect on tissue regeneration, greatly inhibiting the repair or regeneration of tissues. Conventional local delivery of anti-inflammation drugs through physical encapsulation into carriers face the challenges of uncontrolled release. The construction of an inflammation-responsive prodrug to release anti-inflammation drugs depending on the occurrence of inflammation to regulate chronic inflammation is of high need. Here, we construct nanofiber-based scaffolds to regulate the inflammation response of chronic inflammation during tissue regeneration. An inflammation-sensitive prodrug is synthesized by free radical polymerization of the indomethacin-containing precursor, which is prepared by the esterification of N-(2-hydroxyethyl) acrylamide with the anti-inflammation drug indomethacin. Then, anti-inflammation scaffolds are constructed by loading the prodrug in poly(ε-caprolactone)/gelatin electrospun nanofibers. Cholesterol esterase, mimicking the inflammation environment, is adopted to catalyze the hydrolysis of the ester bonds, both in the prodrug and the nanofibers matrix, leading to the generation of indomethacin and the subsequent release to the surrounding. In contrast, only a minor amount of the drug is released from the scaffold, just based on the mechanism of hydrolysis in the absence of cholesterol esterase. Furthermore, the inflammation-responsive nanofiber scaffold can effectively inhibit the cytokines secreted from RAW264.7 macrophage cells induced by lipopolysaccharide in vitro studies, highlighting the great potential of these electrospun nanofiber scaffolds to be applied for regulating the chronic inflammation in tissue regeneration.

Enhanced electrochemical and capacitive deionization performance of metal organic framework/holey graphene composite electrodes.

In this paper, we designed and prepared a novel metal organic framework (MOF)/holey graphene (HG) composites as electrode materials for electrochemistry and capacitive deionization (CDI). The MOF nanoparticles were attached to the surface of the HG sheets to form layered porous structure, which promoted the transport of ions and electrons in the electrode/electrolyte interfaces. Additionally, the synergistic effect of these composite electrodes, which combined pseudocapacitance performance of MOF and the high conductivity of graphene, contributed to enhancing the performance of electrochemistry and CDI. The MOF/HG-2 exhibited high capacitances of 526 F g-1 at current rates of 0.1 A g-1, low charge transfer resistance of 0.53 Ω, and excellent cycling stability (retention of about 90.3% after 5000 cycles at 2 A g-1). As electrode materials for CDI, the MOF/HG-2 displayed a remarkable electrosorption capacity of 39.6 mg g-1 with initial salt concentration of 800 mg L-1, and there was no obvious attenuation after 20 CDI regeneration cycles. These results confirmed that MOF/HG was a promising electrode material for the actual application of CDI.

An Enzyme-Responsive Prodrug with Inflammation-Triggered Therapeutic Drug Release Characteristics.

Long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) for relieving inflammatory reactions can lead to severe side effects. It is of great importance to configure new dosing strategies for alleviating the side effects of NSAIDs. In this work, an enzyme-responsive anti-inflammatory prodrug capable of generating indomethacin upon the trigger of inflammation is developed. A monomer is first prepared after the esterification of carboxyl groups of indomethacin by hydroxyl groups of N-(2-hydroxyethyl) acrylamide. Then, a polymer prodrug, with indomethacin linked through ester bonds on the side chain, is synthesized by free radical polymerization of the monomer. The therapeutic drug component can be triggered to release from the prodrug under the stimulation of cholesterol esterase, mimicking the inflammation environment. On the contrary, there is only a small amount of drug released in the absence of the enzyme. Therefore, the drug can be triggered to release under the stimulation of an environment mimicking inflammation. Furthermore, the in vitro studies at the cellular level indicate that the enzyme-responsive prodrug can efficiently relieve inflammatory responses induced by lipopolysaccharide in RAW264.7 macrophage cells while indicating no cytotoxicity.

Enhanced Hybrid Capacitive Deionization Performance by Sodium Titanium Phosphate/Reduced Porous Graphene Oxide Composites.

In this study, sodium titanium phosphate/reduced porous graphene oxide (NTP/rPGO) composites are used as novel electrode materials for hybrid capacitive deionization (HCDI). The composites are synthesized through assembling the NaTi2(PO4)3 precursor with etched graphene oxide under hydrothermal condition. The NTP/rPGO composites demonstrate a porous hierarchical structure, where uniformly dispersed NaTi2(PO4)3 particles are attached on the rPGO sheets, which provide abundant adsorption sites, highly conductive networks, and short diffusion lengths for salt ions. Benefiting from the redox reaction of the NTP and electrical double-layer capacity of the rPGO, the NTP/rPGO composite containing 77 wt % NaTi2(PO4)3 presents a high specific capacity of 396.42 F g-1 and a high electrosorption capacity of 33.25 mg g-1 at the voltage of 1.4 V with the initial salt conductivity of 1600 µS cm-1 (786 mg L-1). Further, it also shows excellent recycling stability and rapid desalination rate of 0.30 mg g-1 s-1 (100 times as fast as the bare graphene electrode). Therefore, the NTP/rPGO composites exhibit a promising prospect for desalination application in the HCDI system.

A Comprehensive Curation Shows the Dynamic Evolutionary Patterns of Prokaryotic CRISPRs.

Motivation. Clustered regularly interspaced short palindromic repeat (CRISPR) is a genetic element with active regulation roles for foreign invasive genes in the prokaryotic genomes and has been engineered to work with the CRISPR-associated sequence (Cas) gene Cas9 as one of the modern genome editing technologies. Due to inconsistent definitions, the existing CRISPR detection programs seem to have missed some weak CRISPR signals. Results. This study manually curates all the currently annotated CRISPR elements in the prokaryotic genomes and proposes 95 updates to the annotations. A new definition is proposed to cover all the CRISPRs. The comprehensive comparison of CRISPR numbers on the taxonomic levels of both domains and genus shows high variations for closely related species even in the same genus. The detailed investigation of how CRISPRs are evolutionarily manipulated in the 8 completely sequenced species in the genus Thermoanaerobacter demonstrates that transposons act as a frequent tool for splitting long CRISPRs into shorter ones along a long evolutionary history.

A linear comprehensive adsorption model of hydrogen on super activated carbon under supercritical conditions.

The adsorption isotherms of hydrogen on super activated carbon were measured systematically, covering a temperature range of 93-293 K at 20 K intervals and pressures up to 7 MPa. All the experimental data were linearized by adopting the coordinates ln ln(n) vs 1/(ln P). The results indicate that the adsorption limit (P(lim), n(lim)) exists virtually at high pressure and has a certain physical meaning. Based on the adsorption limit, further analyses were carried out by modeling the adsorption isotherms in the coordinates ln(n(lim)/n) vs ln(RT(ln(P(lim)/P) and a linear comprehensive adsorption model was proposed in the form n (lim)=n.exp(psi T+lambda/T-c/) (beta).[RT ln( P (lim)P )] (b) which can predict the adsorption isotherm of hydrogen on activated carbon in supercritical conditions.