Enhanced direct interspecies electron transfer and methane production during anaerobic digestion of fat, oil, and grease by coupling carbon-based conductive materials and exogenous hydrogen.

To investigate the combination of carbon-based conductive materials and exogenous hydrogen (EH2) on methane recovery from fat, oil, and grease (FOG), granular activated carbon (GAC) and carbon cloth (CC) were chosen to collaborate with EH2, resulting in increased methane production by 59 % and 84 %, respectively. Further digestion of long chain fatty acids (LCFAs) confirms that enhanced direct interspecies electron transfer (DIET) was achieved in the reactors with GAC/CC + EH2 than those with GAC/CC only. Other evidences (such as increased microbial population and rapid degradation of volatile fatty acids) were found to support the role of GAC/CC + EH2 in promotion of DIET. Significant change of microbial community was observed using GAC/CC + EH2, which was mainly attributed to the enrichment of electrogenic species (such as Spirochaetaceae, Syntrophomonas palmitatica, and Methanosaeta), leading to some changes in metabolic pathways during acidogenesis and methanogenesis. Together, enhanced DIET was achieved by GAC/CC + EH2, thus improving the methane recovery from FOG.

The fluorescent probe based on methyltetrahydroxanthylium skeleton for the detection of hydrazine.

Two probes based on tetrahydroxanthylium unit (probe 1a) and methyltetrahydroxanthylium unit (probe 1b) were designed and synthesized for the detection of hydrazine. Probes 1a-b exhibited turn-on red emission signal and high selectivity toward NH2NH2. The response time of probe 1a to NH2NH2 was more than 60 min, while that of probe 1b was less than 30 min. The detection limits of probes 1a-b were calculated as 210 nM and 110 nM respectively. What's more, the tolerance experiments showed that methyltetrahydroxanthylium unit possessed higher tolerance toward nucleophiles. Moreover, cells imaging experiments demonstrated that probe 1b could detect exogenous NH2NH2 in living HeLa cells.

A novel xanthylene-based effective mitochondria-targeting ratiometric cysteine probe and its bioimaging in living cells.

In this study, a mitochondria-specific fluorescent probe for efficient ratiometric detection of Cys was designed and investigated. Probe 1 is composed of a xanthylene skeleton and a benzyl group containing an acryloyl moiety. The probe showed excellent water solubility, good selectivity and sensitivity toward Cys over other analytes, and afforded an extremely low detection limit of 33.7 nM. The possible detection mechanism was ascertained by HRMS analysis. Moreover, probe 1 had excellent mitochondrial-targeting ability (the Pearson's correlation coefficient was 0.96), and was capable of monitoring endogenous Cys in living HeLa cells by dual channel ratiometric bioimaging, demonstrating its significant potential in biological applications.

Adenine-based small molecule fluorescent probe for imaging mitochondrial nucleic acid.

A small molecule fluorescent probe (probe 1) based on adenine-coumarin derivative was designed and synthesized in this paper. Probe 1 exhibited a significant fluorescence-enhancing response to nucleic acids at 495 nm (for DNA) and 487 nm (for RNA). The fluorescence enhancement of probe 1 for DNA and RNA was 5.68 and 9.73 times respectively, the fluorescence quantum yield was changed from 2.5% to 11.7% and 22.5% accordingly. Meanwhile, an excellent linear relationship of fluorescence intensity at 495 nm or 487 nm versus the nucleic acid concentration (1 µM for probe 1, 0-350 µg/mL for DNA and 0-300 µg/mL for RNA) was obtained. Co-staining and nucleic acid digestion experiments showed that probe 1 could selectively image nucleic acids in mitochondria and nucleoli in HeLa cells.

Benzoxazine-based fluorescent probes with different auxochrome groups for cysteine detection.

Three 5H-benzo[a]phenoxazin-5-one-based (benzoresorufin and nile-red) Cysteine (Cys) detection probes have been comparatively designed and synthesized in this paper. The optical experiments exhibit probe 1b with a crotonoyl group has no response toward Cys; while probes 1a and 1c have the same reaction site (acryloyl group), their optical responses to Cys are quite different. The benzoresorufin-based-probe 1a shows a turn-on fluorescence response (118-fold) to Cys at 631 nm and affords a very low detection limit (DL = 19.8 nM). Compared with probe 1a, the nile-red-based probe 1c displays gradually diminishing fluorescence intensity with increased Cys concentration at 665 nm. And the notable different fluorescence response mechanisms of probes 1a and 1c toward Cys can be interpreted by HRMS and time-dependent density functional theorety (TDDFT) calculations. Furthermore, both of the two probes indicate high sensitivity and selectivity toward Cys over other similar structured amino acids including homocysteine (Hcy) and glutathione (GSH). Further cellular applications of the two probes have been successfully performed in HeLa cells.

Monotone dynamics and global behaviors of a West Nile virus model with mosquito demographics.

In this paper a mathematical model is formulated to study transmission dynamics of West Nile virus (WNv), which incorporates mosquito demographics including pair formation, metamorphic stages and intraspecific competition. The global behaviors of the model are obtained from a geometric approach and theory of monotone dynamics, even though bistability is present due to backward bifurcation. It turns out that the model can be investigated through two auxiliary subsystem, which are cooperative and K-competitive, respectively. Together with implement of compound matrices and Poincaré-Bendixson theorem, a thorough classification of dynamics of the full model is characterized by mosquito reproduction number [Formula: see text], WNv reproduction number [Formula: see text] and a bistability subthreshold [Formula: see text]. The theoretical results show that if [Formula: see text] is not greater than 1, mosquitoes will not survive, and the WNv will die out; if [Formula: see text] is greater than 1, then mosquitoes will persist, and disease may prevail or vanish depending on basin of attraction of the local attractors which are singletons. Our method in this paper can be applied to other mosquito-borne diseases such as malaria, dengue fever which have a similar monotonicity.

Fluorescent hydrogen sulfide probes based on azonia-cyanine dyes and their imaging applications in organelles.

Three hydrogen sulfide (H2S) probes based on an azonia-cyanine skeleton were successfully designed and prepared. Probe 1a, containing 4-chloro-7-nitro-1,2,3-benzoxadiazole connected to the cyanine dye, had an emission at 660 nm that was enhanced 4.5-fold by the reduced photoinduced electron transfer process when reacting with H2S. Probes 1b and 1c were constructed from cyanine dyes with electron withdrawing 2,4-dinitrophenyl and 7-nitrobenzo[c] [1,2,5]oxadiazol-4-yl groups, respectively. Probes 1b and 1c gave off-on type responses with 169- and 17-fold fluorescent enhancements at 639 nm with H2S. Their emission properties were influenced by intramolecular hydrogen bonds and intramolecular charge transfer processes. The detection limits of probes 1a-1c were calculated at 178, 121, and 9.6 nM, respectively. The intracellular imaging experiments with HeLa cells indicated probe 1a was a mitochondria-targeting H2S probe, while probes 1b and 1c were lysosome-targeting H2S probes.

Tetradecanuclear and Octadecanuclear Gold(I) Sulfido Clusters: Synthesis, Structures, and Luminescent Selective Tracking of Lysosomes in Living Cells.

Reactions of the phosphanyl-gold(I) precursor [(AuCl)2(bdppmapy)] (1; bdppmapy = N,N-bis(diphenylphosphanylmethyl)-2-aminopyridine) with Na2S in a 1:1 or 1:2 molar ratio gave rise to one tetradecanuclear and one octanuclear Au(I) sulfido cluster, [Au14S6(bdppmapy)5]Cl2 (2) and [Au18S8(bdppmapy)6]Cl2 (3), respectively. The former displays a new structural framework in gold cluster chemistry. Compounds 2 and 3 showed strong green luminescence and were employed as excellent imaging probes to selectively light up the lysosomes of living cells. Their long-term tracking of lysosomes can be achieved for up to 36 h, while tracking with commercial Lyso-Tracker Red under the same conditions was limited to 3 h. Our work demonstrated the possibility of constructing novel gold(I) sulfido clusters supported by special P-N hybrid ligands and the potential application of these clusters as long-term selective trackers of lysosomes in bioimaging.

The fluorescent biomarkers for lipid droplets with quinolone-coumarin unit.

Two quinolone-coumarin skeleton derivatives (1a, 1b) have been prepared by Friedländer synthesis with 2-aminoaryl ketone and 3-acetyl-7-diethylaminocoumarin. The dyes showed excellent photo stability. Their optical properties in five organic solvents have been measured, and the wavelength range of the maximum fluorescence emission peaks was from 469 nm to 509 nm. Besides, both of them exhibited high fluorescence quantum yields (0.79-0.96) in these organic solvents. The pH influenced optical properties tests indicated dyes 1a-b have strong fluorescence in sub acid (pH = 6.0) to alkaline environment (pH = 9.0). Their fluorescence quantum yields in neutral aqueous solution (pH = 7.0) were 0.82 (1a) and 0.78 (1b) respectively. In addition, dyes 1a-b exhibited stable fluorescence intensity in the presence of some metal cations and biomolecules in neutral solution (pH = 7.0). Subsequently, confocal microscopy imaging indicated that dyes 1a-b could be used as biomarkers for lipid droplets in living and fixed cells (I929 and HeLa cells).

Construction of dual-functional polymer nanomaterials with near-infrared fluorescence imaging and polymer prodrug by RAFT-mediated aqueous dispersion polymerization.

The performance of functional polymer nanomaterials is a vigorously discussed topic in polymer science. We devoted ourselves to investigating polymer nanomaterials based on near-infrared (NIR) fluorescence imaging and polymer prodrug in this study. Aza-boron dipyrromethene (BODIPY) is an important organic dye, having characteristics such as environmental resistance, light resistance, high molar extinction coefficient, and fluorescence quantum yield. We incorporated it into our target monomer, which can be polymerized without changing its parent structure in a polar solvent and copolymerized with water-soluble monomer to improve the solubility of the dye in an aqueous solution. At the same time, the hydrophobic drug camptothecin (CPT) was designed as a prodrug monomer, and the polymeric nanoparticles (NPs) with NIR fluorescence imaging and prodrug were synthesized in situ in reversible addition-fragmentation chain transfer (RAFT)-mediated aqueous dispersion polymerization. The dynamic light scattering (DLS) and transmission electron microscopy (TEM) revealed the final uniform size of the dual-functional polymeric NPs morphology. The dual-functional polymeric NPs had a strong absorption and emission signal in the NIR region (>650 nm) based on the fluorescence tests. In consideration of the long-term biological toxicity, confocal laser scanning microscopy (CLSM) results indicated that the dual-functional NPs with controlled drug content exhibited effective capability of killing HeLa cells. In addition, in vivo imaging of the dual-functional NPs was observed in real time, and the fluorescent signals clearly demonstrated the dynamic process of prodrug transfer.

Many-to-many multicast routing schemes under a fixed topology.

Many-to-many multicast routing can be extensively applied in computer or communication networks supporting various continuous multimedia applications. The paper focuses on the case where all users share a common communication channel while each user is both a sender and a receiver of messages in multicasting as well as an end user. In this case, the multicast tree appears as a terminal Steiner tree (TeST). The problem of finding a TeST with a quality-of-service (QoS) optimization is frequently NP-hard. However, we discover that it is a good idea to find a many-to-many multicast tree with QoS optimization under a fixed topology. In this paper, we are concerned with three kinds of QoS optimization objectives of multicast tree, that is, the minimum cost, minimum diameter, and maximum reliability. All of three optimization problems are distributed into two types, the centralized and decentralized version. This paper uses the dynamic programming method to devise an exact algorithm, respectively, for the centralized and decentralized versions of each optimization problem.