Department of Chemistry and Material Sciences

Genetic circuits and metabolic pathways can be reengineered to allow organisms to process signals and manufacture useful chemicals. However, their functions currently rely on organism-specific regulatory parts, fragmenting synthetic biology and metabolic engineering into host-specific domains. To unify efforts, here we have engineered a cross-species expression resource that enables circuits and pathways to reuse the same genetic parts, while functioning similarly across diverse organisms. Our engineered system combines mixed feedback control loops and cross-species translation signals to autonomously self-regulate expression of an orthogonal polymerase without host-specific promoters, achieving nontoxic and tuneable gene expression in diverse Gram-positive and Gram-negative bacteria. Combining 50 characterized system variants with mechanistic modelling, we show how the cross-species expression resource's dynamics, capacity and toxicity are controlled by the control loops' architecture and feedback strengths. We also demonstrate one application of the resource by reusing the same genetic parts to express a biosynthesis pathway in both model and non-model hosts.

We reported a reactive probe for HSO3(-), which showed a colorimetric and ratiometric fluorescence response to HSO3(-) with fast response (t1/2 = 20 s), good specificity and low detection limit (3.0 nM). The probe was cell membrane permeable and successfully used for visualizing trace SO2 derivatives in living cells.

A novel fluorescent probe displayed a colorimetric response to ClO − with high selectivity, fast response and a low detection limit (0.08 μM).

Coordination polymers (CPs) with bismuth(iii) as a connectivity centre have been prepared from BiX3 (X = Cl-I) and 4,4'-bipyridine (bipy) in order to implement Bi-based luminescence. The products were obtained via different synthetic routes such as solution chemistry, melt syntheses or mechanochemical reactions. Five neutral and anionic 1D-CPs are presented that show a chemical parallel to trivalent lanthanides forming isostructural or closely related 1D-CPs, of which five additional compounds are described. Bi3+ proves to be a versatile cation for luminescence resulting from energy transfer processes between a metal and a ligand in the presented CPs. Quantum chemical calculations were carried out to investigate Bi3+-participation in the luminescence processes. The calculated results allow an assignment of the bright transitions composed of mainly metal-to-ligand-charge transfer (MLCT) character. These results show that Bi3+ can form strongly luminescent coordination compounds with N-donor ligands.

This short contribution is aimed to describe two plasma processes utilized at the group of the authors for biomedical applications, namely: the grafting process of polar groups intended to obtain stable hydrophilic surfaces on hydrophobic polymers, and the deposition of thin organic coatings highly functionalized with carboxylic groups. Both processes can develop cell-adhesive surfaces onto biomedical polymers. Combined with plasma deposition processes of non fouling coatings through a "physical mask", such methods can provide substrates patterned with diverse micrometric domains that can drive adhesion, spreading and growth of cells along predefined directions, an useful approach utilized in tissue engineering.

The deformation of duplex structures in general and duplex stainless steels (DSS) in particular is very complex. The existence of the massive second phase leads to numerous unexpected features, i.e. the microstructure is the most decisive influence parameter on the deformation behavior of duplex structures. In the case of DSS additionally the chemical composition has to be taken into account. With increasing rolling deformation at room temperature several deformation mechanisms occur, e.g. shear relaxation, twinning of austenite, deformation induced martensitic transformation of the austenitic phase, crack formation (and crack healing accompanied by the refinement of the microstructure) and dynamic recovery. In α/γ DSS additionally the phase boundaries (PB) are obstacles for deformation. Therefore, here large deformation zones were built up during deformation which contribute to the complex deformation behavior. Since nitrogen reduces the SFE and, thereby, hardens the austenitic phase and promotes planar slip which is not homogeneously distributed in the austenitic grains but localized, ferrite becomes the more ductile phase in DSS. Furthermore, as a very strong austenite stabilizing element, N causes the change of the matrix phase form ferrite to austenite and leads to the ductile to brittle transition of austenite which also influences the deformation behavior. It occurred that there are equal deformation modes like the hindrance of shear band formation, shear band cracking and "selective phase boundary sliding", which are obviously valid for all duplex structures, and other ones, due to the nitrogen content (e.g. brittleness) or the existence of the second phase (e.g. increased strain hardening rate).

Alkyl dialkylphosphinates, thionates, thioates, and dithioates have been studied under alkaline hydrolysis conditions in 60% DME – H2O and pure H2O. Substitution of S for O in the phosphoryl group has only a small rate retarding effect, typically less than a factor of 10. The effect of the similar replacement in the leaving group, however, can lead to rate increases greater than a factor of 100. Activation parameters were determined and the ΔS* values range from −19 to −49 eu for the bimolecular reactions. The more negative values are for the esters with higher sulfur content and/or sterically large substituents. The results are discussed in terms of a pathway involving a pentacoordinate intermediate.

Thioesterases catalyze hydrolysis of acyl thioesters to release carboxylic acid or macrocyclization to produce the corresponding macrocycle in the biosynthesis of fatty acids, polyketides, or nonribosomal peptides. Recently, we reported that the thioesterase CmiS1 from Streptomyces sp. MJ635-86F5 catalyzes the Michael addition of glycine to an α,β-unsaturated fatty acyl thioester followed by thioester hydrolysis in the biosynthesis of the macrolactam antibiotic cremimycin. However, the molecular mechanisms of CmiS1-catalyzed reactions are unclear. Here, we report on the functional and structural characterization of the CmiS1 homolog SAV606 from Streptomyces avermitilis MA-4680. In vitro analysis indicated that SAV606 catalyzes the Michael addition of glycine to crotonic acid thioester and subsequent hydrolysis yielding ( R )- N -carboxymethyl-3-aminobutyric acid. We also determined the crystal structures of SAV606 both in ligand-free form at 2.4 Å resolution and in complex with ( R )- N -carboxymethyl-3-aminobutyric acid at 2.0 Å resolution. We found that SAV606 adopts an α/β hotdog fold and has an active site at the dimeric interface. Examining the complexed structure, we noted that the substrate-binding loop comprising Tyr-53–Asn-61 recognizes the glycine moiety of ( R )- N -carboxymethyl-3-aminobutyric acid. Moreover, we found that SAV606 does not contain an acidic residue at the active site, which is distinct from canonical hotdog thioesterases. Site-directed mutagenesis experiments revealed that His-59 plays a crucial role in both the Michael addition and hydrolysis via a water molecule. These results allow us to propose the reaction mechanism of the SAV606-catalyzed Michael addition and thioester hydrolysis and provide new insight into the multiple functions of a thioesterase family enzyme.

Bismuth halides represent an emergent class of materials that combines semiconductor properties with non-toxic constituents. However, many simple bismuth halide compounds feature bandgaps that are significantly higher than those of the lead halide perovskites, which they are supposed to replace. One way to address this issue is the preparation of multinary metal halide materials that feature an additional metal ion. Here, we report on the synthesis and properties of (HPy)2(Py)CuBi3I12 (1) a new copper iodido bismuthate, a photoconductor, which shows a low band gap of 1.59 eV and good thermal and air stability.

(Me2C[double bond, length as m-dash]NMe2)Bi2I7 represents a new layered organic-inorganic iodido bismuthate. It displays an unprecedented anion topology, a low band gap and good stability. Advanced electronic structure analysis finds the II interactions to be decisive for the compound's structural and electronic properties.

Abstract The conditions governing the rate of flow of ionic and non-ionic liquids in narrow channels are examined, and it is demonstrated that in certain circumstances the electrical resistance to shear in ionic liquids, due to the effect of an electrical potential gradient on the ions of the surface layers, may assume considerable importance relative to the mechanical (viscous) resistance to shear. The results of this analysis are of important application in various fields, and offer an explanation of anomalous results obtained by numerous experimental workers.

This paper represents the results from the initial phase of a research program to determine the flow characteristics of the C-130 Hercules transport aircraft. The initial phase of the program consists of evaluation and comparison of the flow-field obtained from flow visualization methods. Specifically CFD (Computational Fluid Dynamics) results are compared with experimental Hot Wire results produced by wind tunnel tests on the C-130 in clean configuration. This paper outlines the results to date and provides a description of further work. The CFD element of this research features the use of Detached Eddy Simulation (DES) in order to extend its use as a reliable method for use on complex flow-fields. DES combines the efficiency of a Reynolds-averaged turbulence model near the wall with the fidelity of LES (Large Eddy Simulation) in separated regions. Because of the LES treatment in separated regions, it provides more accurate descriptions of the geometry-dependant, three-dimensional unsteady motions resulting in regions of massive separation. The computational aspect of the research is performed at the US Air Force Academy, with subsequent wind tunnel tests (Hot Wire) being undertaken in France at ENSICA.

Abstract o‐Benzoylbenzenesulfonyl chlorides (I) were prepared conveniently from aminobenzophenones by diazotization followed by reaction with sulphur dioxide in the presence of Cu+, according to the general method of Meerwein. Reaction of the sulfonyl chlorides with hydrazine led to 4‐phenyl‐2H‐1,2,3‐benzothiadiazine‐1,1‐dioxides (II). The latter compounds could be methylated and acetylated readily in the 2‐position. The 2‐methyl derivative (III) could be prepared also by reaction of the sulfonyl chloride (Ia) with methylhydrazine. Catalytic hydrogenation of 6‐chloro‐4‐phenyl‐2H‐1,2,3‐benzothiadiazine‐1,1‐dioxide (IIa) gave the 3,4‐dihydro derivative (V). Reaction of the sulfonyl chlorides (I) with o‐phenylenediamine followed by cyclodehydration led to 11H‐11,11a‐dihydrobenzimidazo[1,2‐b] [1,2]benzisothiazole‐5,5‐dioxides (VII). One of the latter compounds (VIIa) in sodium hydroxide solution in the presence of methyl iodide or benzyl chloride was transformed into 6‐methyl‐ and 6‐benzyl‐5H‐dibenzo[c,g] [1,2,6]thiadiazocine‐5,5‐dioxides (VIII), respectively. 5H‐Dibenzo[c,g] [1,2,6] thiadiazocine‐6,6‐dioxides (XIV) were prepared also by cyclodehydration of 2‐amino‐2′‐benzoylbenzenesulfonanilides (XIII).

ZnFe2O4 nano-catalyzed facile synthesis of tetrahydropyranoquinoline derivatives (4a–f) via one-pot multi-component Povarov’s inverse-electron-demand hetero Diels–Alder reaction of substituted aromatic aldehyde (1), aromatic amine (2) with dihydrofuran (3) under ultrasonic irradiation. This may be helpful to society to get more active pharmaceutical ingredients. In the present study, a series of tetrahydroquinoline (4a–f) were synthesized and confirmed with several spectral characterization techniques. Synthetic approach of present research toward the synthesis of THQ was significantly shown that ZnFe2O4 plays a vital role in highly efficient, eco-friendly, recyclable heterogeneous nano-catalysts. This resulted in enhancing reaction rate, solvent-free reaction, easy to carry, simple isolation, and high yielded product.

Yonezo Morino, Takeshi Ukaji, Tetsuzo Ito; An Electron Diffraction Investigation of the Molecular Species in the Vapor Phase of the GaAs-I2 System, Bulleti

A two-step process involving coagulation-flocculation followed by solar photocatalysis – based Advanced Oxidation Process (AOP) using TiO2-Reduced Graphene Oxide (TRGO) nanocomposite as catalyst has been employed for the treatment of pulp and paper mill effluent. As the effluent is loaded with a high amount of organics with initial chemical oxygen demand (COD) as high as 3516, a pre-treatment is required before applying photocatalytic treatment. Coagulation-flocculation was identified as an effective pre-treatment strategy. Among the various coagulants tested, CuSO4.5H2O showed the best % COD reduction of 84 at pH 6, at a loading of 5 g/L. The primary treatment of coagulation improved the biodegradability index from 0.23 to 0.37. TRGO photocatalyst, employed in the second stage of photocatalytic treatment was synthesised by an ultrasound assisted solvothermal method and well characterised by various spectroscopic/analytical tools. The composite was found to be an efficient solar photocatalyst and achieved 1.76 and 2.1 times more COD reduction than synthesised TiO2 and commercial P25 respectively. The final effluent after the combined treatment was neutral and the biochemical oxygen demand (BOD) and COD were 11.7 and 120 mg/L respectively which were below the given limit of National Environmental Quality Standards.

During the synthesis of the literature-known iodido antimonate [Cu(MeCN)4]4[Sb3I11]2 (MeCN = acetonitrile), four transient compounds, [Cu(MeCN)4]4[Sb6I22]·2MeCN (1), [Cu(MeCN)4]4[Sb7I25]·MeCN (2), [Cu(MeCN)4]4[Sb10I34] (3) and [Cu(MeCN)4]4[Sb8I28] (4), were identified. The compounds appeared within hours or days and subsequently re-dissolved in the mother liquor, leading to [Cu(MeCN)4]4[Sb3I11]2 as the final product. Single crystal X-ray analysis showed that all four compounds feature unprecedented anion motifs.

Sample preparation is one of the viable procedures to be used before analysis to enhance sensitivity and reduce the matrix effect. The current review is mainly emphasized the latest outcome and applications of microextraction techniques based on the miniaturization of the classical conventional methods based on liquid-phase and solid-phase extraction for the quantitative elemental analysis in different real samples. The limitation of the conventional sample preparation methods (liquid and solid phase extraction) has been overcome by developing a new way of reducing size as compared with the conventional system through the miniaturization approach. Miniaturization of the sample preparation techniques has received extensive attention due to its extraction at microlevels, speedy, economical, eco-friendly, and high extraction capability. The growing demand for speedy, economically feasible, and environmentally sound analytical approaches is the main intention to upgrade the conventional procedures apply for sample preparation in environmental investigation. A growing trend of research has been perceived to quantify the trace for elemental analysis in different natures of real samples. This review also recapitulates the current futuristic scenarios for the green and economically viable procedure with special overemphasis and concentrates on eco-friendly miniaturized sample-preparation techniques such as liquid-phase microextraction (LPME) and solid-phase microextraction (SPME). This review also emphasizes the latest progress and applications of the LPME and SPME approach and their future perspective.

Abstract It is demonstrated that the rate of sedimentation of a system of particles in an ionic liquid may vary markedly with the ionic concentration, due to variation in the electroviscous forces which resist shear in the double layer of ions associated with each particle. Equations governing the rate of sedimentation are derived, and used to calculate values for the electro-kinetic potentials of carborundum in potassium chloride solutions, from data on sedimentation velocity. These values are compared with those previously obtained from data on electro-endosmosis.

Abstract Preliminary experimental evidence for the existence of the electroviscous in ionic liquids is submitted. The theoretical predictions of the previous paper have been qualitatively confirmed, and quantitative experimental work is now in progress. The rate of approach of surfaces in various liquids has been observed, and it has been demonstrated that equilibrium distances of separation under finite pressures are very small.