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In January 2017, the 2nd Brigade Combat Team, 82nd Airborne Division, deployed to bolster the Iraqi Security Forces (ISF) in the campaign to annihilate the so-called Islamic State (IS). Task [...]

One of the key factors to construct a productive whole-cell biocatalytic cascade may include the design of the biotransformation pathways, discovery and engineering of the cascade enzymes, and functional and balanced expression of the cascade enzymes in microbial cells as well as systematic engineering of the whole-cell biocatalytic cascades. Such issues are covered in this review exemplified for the biotransformation of renewable fatty acids into industrially relevant oleochemicals (e.g., medium-chain fatty acids such as n-nonanoic acid, 9-hydroxynonanoic acid, 9-aminononanoic acid, and 1,9-nonanedioic acid) as model systems.

Two-dimensional (2D) metal-free sheets with atomic thickness have been highly considered as promising candidates for fluorescent probes, due to their intriguing characteristics. In this work, 2D ultrathin boron nanosheets (B NSs) with a surface defect nanolayer can be effectively prepared by modified liquid phase exfoliation. The as-prepared ultrathin B NSs show blue fluorescence characteristics even with a quantum yield efficiency of up to 10.6%. Such luminescent behavior originates from the quantum confinement effect and the existence of a surface defect layer. In light of the advantages of being environmentally friendly, having high photostability and good biocompatibility, for the first time we have shown that ultrathin B NSs can be used as an emerging fluorescent probe for application in cellular bioimaging. It is believed that this work will open new avenues for ultrathin B NSs in biomedical fields, and it will also inspire the development of other elemental 2D nanomaterials.

Downsizing the costly noble metals to the single-atomic level has attracted extensive attention due to the maximum atom efficiency, low coordination, and sufficient exposure of isolated active metal centers. Herein, with a focus on the functionalization of the palladium phthalocyanines with four aminophenoxy groups at the periphery of the benzene ring (PdPc-TAP), we successfully anchored the isolated Pd single atoms onto graphene (Pd ISAs/GNS) viathe in situimmobilization and pyrolysis of PdPc-TAP. The omni bearing imprisonment of the Pd sites (XY-axis stabilized by the planar macrocyclic Pc and Z-axis anchored from the interactions between the claw-like tetra-amino groups and GO) is the key factor for the formation of Pd ISAs/GNS. The model hydrogenation reaction and density functional theory calculation revealed that the demonstrated catalytic activity of Pd ISAs/GNS was 21.3 times higher than that of the Pd/C, which is attributed to the near-zero adsorption of active H* species on Pd ISAs/GNS that can accelerate the preferential migration of dissociative H* species to the target molecule. This work not only highlights the synthesis and application of the noble metal-based single-atom catalyst, but also provides a versatile strategy for the construction of single-atom catalysts from the viewpoint of substituent-modified rigid molecules.

l-Carnosine (l-Car, β-alanyl-l-histidine) is a bioactive dipeptide with important physiological functions. Direct coupling of unprotected β-Ala (β-alanine) with l-His (l-histidine) mediated by an enzyme is a promising method for l-Car synthesis. In this study, a new recombinant dipeptidase (SmPepD) from Serratia marcescenswith a high synthetic activity toward l-Car was identified by a genome mining approach and successfully expressed in Escherichia coli. Divalent metal ions strongly promoted the synthetic activity of SmPepD, with up to 21.7-fold increase of activity in the presence of 0.1 mM MnCl2. Higher temperature, lower pH and increasing substrate loadings facilitated the l-Car synthesis. Pilot biocatalytic syntheses of l-Car were performed comparatively in batch and continuous modes. In the continuous process, an ultra-filtration membrane reactor with a working volume of 5 L was employed for catalyst retention. The dipeptidase, SmPepD, showed excellent operational stability without a significant decrease in space–time yield after 4 days. The specific yield of l-Car achieved was 105 gCargcatalyst−1by the continuous process and 30.1 gCargcatalyst−1by the batch process. A nanofiltration membrane was used to isolate the desired product l-Car from the reaction mixture by selectively removing the excess substrates, β-Ala and l-His. As a result, the final l-Car content was effectively enriched from 2.3% to above 95%, which gave l-Car in 99% purity after ethanol precipitation with a total yield of 60.2%. The recovered substrate mixture of β-Ala and l-His can be easily reused, which will enable the economically attractive and environmentally benign production of the dipeptide l-Car.

Nanoscale zero-valent iron (nZVI) was known to inactivate various microbes, but the impact of extracellular polymeric substances (EPS) on the bactericidal effect of nZVI remained poorly understood. In this study, we seek to clarify the role of capsular EPS in nZVI inactivation of Escherichia coliunder aerobic conditions, by employing parental and isogenic mutants with controlled EPS secretion for comparison. The results indicated that increased EPS of E. colimitigated the toxicity of nZVI. Surprisingly, more EPS favored the adsorption of nZVI on the E. colisurface, and subsequently resulted in enhanced membrane disruption, which contradicted the E. coliinactivation trends. Nonetheless, E. coliwas able to repair the damaged membrane partially with nutrient supply; besides, EPS accelerated the corrosion of nZVI to produce less toxic iron (hydro)oxides. More importantly, EPS could scavenge reactive oxygen species (ROS) produced by oxygenation of nZVI, and prevent ROS from penetrating the cell membrane to damage intracellular structures and macromolecules. Therefore, by increasing EPS secretion, E. colimade trade-offs between physical disruption and oxidative damage to improve the resistance to nZVI inactivation. Besides, similar roles of EPS were also observed in the Gram-positive bacterium Bacillus subtilis. These findings broadened our understanding of the bactericidal mechanism of nZVI, which would benefit the environmental risk assessment of nZVI and the development of ZVI based water disinfection techniques.

The article discusses how the U.S. military is fighting the Islamic State in Syria and Iraq by using the "by-with-through (BWT) operational approach." The approach means that operations are led by U.S. partners, with enabling support from the U.S. or U.S.-led coalitions. Operation Inherent Resolve (OIR) proved infinitely different than the combat in Iraq from 2003 to 2008.

A multi-level supramolecular system produced by single-step Fe3+-mediated ionic crosslinking self-assembly can overcome the critical issues of current sonodynamic therapy (SDT) and address the need to monitor therapeutic effects in vivowith a non-invasive approach. This rational design of organic sonosensitizer-based formulation shows great potential for clinical SDT against deep-seated cancer.

Pt/ZSM-5 catalysts with various crystal sizes were prepared viacompetitive ion-exchange, followed by a slow activation procedure. Even when using very large ZSM-5 crystals, highly dispersed Pt nano-clusters were contained within the zeolite crystal's voids, as ascertained by 2D pressure-jump IR spectroscopy of adsorbed CO and focussed ion-beam transmission electron microscopy. The shape-selective properties of the Pt/ZSM-5 catalysts were evaluated in the partial hydrogenation of soybean oil. Unique hydrogenation selectivities were observed, as the fatty acids located at the central position of the triacylglycerol (TAG) molecules were preferentially hydrogenated. The resulting oil has therefore high levels of intermediately melting TAGs, which are compatible with biolubricants due to their improved oxidative stability and still appropriate low-temperature fluidity. The TAG distribution in the partially hydrogenated soybean oil samples was independent from the zeolite crystal size, while the hydrogenation activity linearly increases with the crystal's external surface area. This trend was confirmed with a Pt loaded mesoporous ZSM-5 zeolite, obtained viaa mild alkaline treatment. These observations imply and confirm a genuine pore mouth catalysis mechanism, in which only one fatty acid chain of the TAG is able to enter the micropores of ZSM-5, where the double bonds are hydrogenated by the crystal encapsulated Pt-clusters.