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Continuum manipulators are widely used in minimally invasive surgical robot systems (MISRS) because of their flexibility and compliance, while their modelling and control are relatively difficult and complex. This paper proposes an improved hysteresis model of a notched continuum manipulator based on the classical Bouc-Wen model, which can reduce errors and increase the accuracy of the kinematic-mechanics coupled model. Then parameters are identified by the mean of genetic algorithm (GA). Hysteresis phenomenon of the mentioned manipulator is actually caused by many factors such as the hysteresis property of Hyperelastic Nitinol Alloy (HNA), the elastic deformation of tendon and the friction between the tendon and the tube. The results of both static and dynamic experiments show that the introduced hysteresis model can eliminate the positional difference between forward and reverse bending processes, and thus improve the forecast precision of deformation during motion. This model can also be used to compensate modelling errors caused by hysteresis of other similar systems. [ABSTRACT FROM AUTHOR]

Magnetic graphene oxide (GO) nanocomposite was assigned to decorate with cationic polymer PDDA (diallyldimethylammonium chloride) to a sponge like nanocomposite GO-Fe 3 O 4 /PDDA, and employed in magnetic harvesting of oleaginous Chlorella sp. HQ. The results showed that huge surface area, light weight and stable dispersion of GO make contribution to the high harvesting efficiency of GO-Fe 3 O 4 (80.14%), compared to Fe 3 O 4 NPs (62.65%) with 70 mg of nanomaterials / L of algal cells dose. In addition, graphene base provides more active sites to further decorate with PDDA, which imparts a positive zeta potential charge (21.94 mV) to nanoflocculants, thereby achieving 95.35% harvesting efficiency within 5 min. The adsorption followed Langmuir isotherm and pseudo-second-order kinetic model, with the maximum adsorption capacity of 14.06 g dry-biomass / g. Moreover, the harvesting efficiency decreased dramatically when pH increased for Fe 3 O 4 NPs, while GO-Fe 3 O 4 and GO-Fe 3 O 4 /PDDA could maintain in a wide pH range. Besides,GO-Fe 3 O 4 /PDDA can be effectively reactivated (88.68% harvesting efficiency after 5 times reactivation) with 70 mg L − 1 dose (add 30 mg L − 1 after every time). It can be expected that this novel graphene-based magnetic nanocomposite has great potential to be a promising magnetic flocculant applied to efficient harvesting of oleaginous microalgae. [ABSTRACT FROM AUTHOR]

Semisolid slurry of A356 aluminum alloy was prepared by Self-Inoculation Method (SIM), and the microstructures and solidification behavior of rheo-forming process in different forming processes were researched. The results indicate that semisolid slurry of A356 aluminum alloy can be prepared by Self-Inoculation Method at 600ºC. Primary α-Al particles with fine and spherical morphology are uniformly distributed when the isothermal holding time of slurry is 3 min. The different forming processes for semisolid rheo-forming can be regarded as the effect of cooling rate on rheo-forming. The primary particle sizes and shape factors are gradually increasing with the increase of cooling rate. The sizes of secondary particles are gradually increasing with the decrease of cooling rate, and the amount of secondary particles in the same areas are gradually decreasing with the decrease of cooling rate. The morphologies of eutectic Si are gradually coarsening from fibrous to needle-like in different forming processes, while the sizes and the lamellar spacing of the eutectic Si are gradually increasing with the decrease of cooling rate. The mechanical properties of the semisolid forming components are gradually increasing with the increase of cooling rate and forming pressure.

Magnetic iron oxide (Fe 3 O 4 ) nanoparticles (MNPs) was assigned to coat with amino-riched polyamidoamine (PAMAM) dendrimer (Fe 3 O 4 @PAMAM; Gn-dMNPs, n = 0, 1, 2, 3) and employed in the magnetic harvesting of oleaginous Chlorella sp. HQ due to the highly positive branched structure. The coating process was realized by stepwise grafting which encompasses Michael addition and amidation reaction. Amino-micromolecular amino acids were used to modify Fe 3 O 4 MNPs as control groups to investigate the difference of microalgal harvesting between modification with polymer and micromolecule firstly. The results showed that the coating of highly positive branched PAMAM dendrimer could dramatically promote the adsorption between algae cells and nanoparticles, leading to a large drop of nanoparticles dosage, compared with amino acid (AA)-modified Fe 3 O 4 MNPs (Fe 3 O 4 @AA). The influence of polymer coating thickness which is an unclear factor on harvesting was explored initially, suggesting that the harvesting efficiency was positively correlated with the coating thickness of PAMAM dendrimer and reached over 95% within 2 min when using 80 mg L −1 G3-dMNPs at pH 8.0. Moreover, the harvesting efficiency rose dramatically when pH decreased from 10.0 to 4.0 for G0 ∼ G2-dMNPs, while the high efficiency for G3-dMNPs could be maintained in a wide pH range for the amino-riched branched structure. It can be attributed to increased electrostatic attraction and bridging flocculation caused by abundant active sites of the highly positive branched network on Fe 3 O 4 MNPs. It can be expected that this novel magnetic flocculant has the potential to be applied to harvesting of oleaginous microalgae due to its high efficiency and cycling stability. [ABSTRACT FROM AUTHOR]

Surface soil samples were collected from urban agglomeration of the Yangtze River Delta (YRD), China in 2003 and 2012, respectively. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were analyzed to determine if there were any changes in their levels and compositional profiles between the two sampling years. The concentrations of ΣPBDEs ranged from 0.553 to 13.0 μg kg(with the mean of 3.31 μg kg) in the 2003 samples and from 1.01 to 43.2 μg/kg (with the mean of 10.0 μg kg) in the 2012 samples. The concentrations of ΣPCBs ranged from 0.301 to 3.29 μg kg(with the mean of 1.01 μg kg) in the 2003 samples and from 0.205 to 3.96 μg/kg (with the mean of 0.991 μg kg) in the 2012 samples. The comparisons between the 2012 and 2003 data showed that PBDEs concentrations increased over the years, but PCB concentrations did not change much. BDE-209 was the major BDE congener in both the 2003 and 2012 samples, indicating that the dominant PBDE mixture production and usage in the YRD had been the commercial deca-BDE mixture. Investigation of the PBDE congener profiles indicated that there had been new input of octa-BDEs in this region in recent years. Little change was found for the pattern of PCBs congener profiles between 2 years' samples. As such, spatial distributions of PBDEs or PCBs in surface soil samples reflected a gradient (from high to low) from the central cities out to rural areas in both the 2003 and 2012 data. In addition, high concentrations of PBDEs were observed in the industrial and residential areas, whereas high concentrations of PCBs were only observed in the industrial areas. [ABSTRACT FROM AUTHOR]

2-Amino-5-mercapto-1,3,4-thiadiazole (AMT) was used to synthesize 24 new compounds. The structures were confirmed by 1H NMR and 13C NMR. [ABSTRACT FROM AUTHOR]

Some novel of 5-arylmethylideneamino-1,3,4-thiadiazole-2-ylsulfanyl acetamide derivatives were synthesized by the S-alkylation of 5-arylmethylideneamino-2-mercapto-1,3,4-thiadiazoles with chloroacetyl anilide under solid–liquid phase transfer catalysis using polyethylene glycol-400 (PEG-400) catalyst in the presence of potassium carbonate. Some of the title compounds were investigated for plant growth-regulating activity. They were found to enhance root elongation remarkably at a low concentration. [Supplemental materials are available for this article. Go to the publisher's online edition ofPhosphorus, Sulfur, and Silicon and the Related Elementsto view the following free supplemental files: Additional figures and tables]. [ABSTRACT FROM PUBLISHER]

Abstract: The theme of this paper is signal decomposition and reconstruction, not specific for or limited to system identification. In dealing with aperiodic damped signals, Prony-based techniques — which decompose a signal into real- and/or complex-valued exponential components — are often utilized. In essence, the derivation of Prony's method has been based on a high order homogeneous difference equation. In this paper, an alternative approach that uses a first-order matrix homogenous difference equation (state-space model) to replace the high order homogenous difference equation is advocated. Although the proposed method and Prony's method appear to be theoretically identical, this paper shows that they are drastically different over crucial numerical issues, including conditioning and stability. While Prony's method is very sensitive to sampling rate and round-off error, the proposed method is not. While Prony's method has trouble to deal with noise embedded in the signal, the proposed method can handle noisy signals properly because it has a build-in noise rejection mechanism via the usage of truncated singular value decomposition. While root-finding of a high order polynomial — a classical ill-conditioned problem — is a required step in Prony's method, the proposed method completely avoids it. The proposed method is also applicable to intermittent signals, and can recover the missing parts of intermittent signals nicely through reconstruction. [Copyright &y& Elsevier]

Objective: To compare anterior and posterior approaches for treating cervical spondylotic myelopathy (CSM) involving more than two levels, especially in regard to quality of life and cost effectiveness. Methods: The authors studied 116 CSM patients who underwent decompressive surgery by either an anterior or a posterior approach with instrumentation. In the anterior group, 1-3 levels subtotal vertebrectomy was followed by bone graft and Orion anterior cervical locking plate fixation. In the posterior group, multilevel laminectomy with posterior screw-rod fixation was performed. Follow-up, which included radiographic assessment, clinical examination and documentation of length of any hospitalization and cost and incidence of complications, was performed 1 day before discharge, 6 months after leaving hospital, and at final follow-up. Results: Both groups had improved clinical outcomes. The anterior group showed greater satisfaction but lower visual analog scale scores than the posterior group, whereas SF-36 emotional role and mental health scores were higher in the anterior group. There was no marked difference between the two groups in length of hospitalization and most of the costs of treating CSM, however treatment and examination fees were significantly higher in the posterior group. Conclusions: Both anterior and posterior decompressions (with instrumentation) are effective procedures for improving the neurological outcomes of patients with CSM. However, although the two approaches have similar health care costs, anterior cervical corpectomy (with instrumentation) seems to be subjectively assessed by patients as better. [ABSTRACT FROM AUTHOR]

A major objective of quantitative trait locus (QTL) studies is to find genes/markers that can be used in breeding programs via marker assisted selection (MAS). We surveyed the QTLs for yield and yieldrelated traits and their genomic distributions in common wheat (Triticum aestivum L.) in the available published reports. We then carried out a meta-QTL (MQTL) analysis to identify the major and consistent QTLs for these traits. In total, 55 MQTLs were identified, of which 12 significant MQTLs were located on wheat chromosomes 1A, 1B, 2A, 2D, 3B, 4A, 4B, 4D and 5A. Our study showed that the genetic control of yield and its components in common wheat involved the important genes such as Rht and Vrn. Furthermore, several significant MQTLs were found in the chromosomal regions corresponding to several rice genomic locations containing important QTLs for yield related traits. Our results demonstrate that meta-QTL analysis is a powerful tool for confirming the major and stable QTLs and refining their chromosomal positions in common wheat, which may be useful for improving the MAS efficiency of yield related traits. [ABSTRACT FROM AUTHOR]

Fifteen 2-(5-substituted-1,3,4-thiadiazolo-2-ylimino)-4-thiazolidinones were efficiently synthesized from the reaction of ammonium thiocyanate with 2-chloro-N-(5-substutited-1,3,4-thiadiazolo-2-yl)acetamides under microwave irradiation. The target compounds were obtained in better yields (75-98%) and shorter time (5 min) than with conventional heating. [ABSTRACT FROM AUTHOR]

Neonicotinoid insecticides are neurotoxicants that cause serious environmental pollution and ecosystem risks. In the present study, a nitenpyram-degrading bacterium, Rhodococcus ruber CGMCC 17550, was isolated from a nitenpyram production sewage treatment tank. Liquid chromatography-mass spectrometry analysis revealed R. ruber degraded nitenpyram via a novel hydroxylation pathway to form three different metabolites, one of which was confirmed to hydroxylate nitenpyram at the C3 site of the 6-chlorpyridine cycle by nuclear magnetic resonance analysis. The nitenpyram degradation rate increased as the biomass of resting R. ruber CGMCC 17550 cells increased, reaching 98.37% at an OD 600 of 9 in transformation broth containing 100 mg L−1 nitenpyram after 72 h of incubation. Nitenpyram degradation by R. ruber CGMCC 17550 was insensitive to dissolved oxygen levels. Use of glucose, fructose and pyruvate as co-substrates slightly increased nitenpyram degradation. The cytochrome P450 inhibitor 1-aminobenzotriazole strongly inhibited nitenpyram degradation, indicating that P450 enzymes may mediate nitenpyram hydroxylation. Inoculation of R. ruber CGMCC 17550 enhanced nitenpyram degradation in surface water. Additionally, R. ruber cells immobilized by calcium-alginate remediated 87.11% of 100 mg L−1 NIT in 8 d. Genome sequencing analysis confirmed that R. ruber CGMCC 17550 has metabolic diversity and abundant KEGG genes involved in xenobiotics biodegradation and metabolism. These findings demonstrate that R. ruber CGMCC 17550 is capable of unique biodegradation of nitenpyram via the hydroxylation pathway and is a promising bacterium for bioremediation of contaminants. • A novel Actinomycetes Rhodococcus ruber CGMCC 17550 degraded nitenpyram efficiently. • Three novel nitenpyram-hydroxylating metabolites were identified. • The hydroxylation of nitenpyram by R. ruber CGMCC 17550 was insensitively to oxygen. • The free cells and immobilized cells remediated nitenpyram in surface water. • The genome of R. ruber CGMCC 17550 has been determined. [ABSTRACT FROM AUTHOR]

The theoretical analysis based on elementary beam theory and the minimization of strain energy, is developed to predict curvatures of bicomponent fibers with arbitrary cross sections. Comparison of the present prediction with other published results is made in the case of rectangular cross section. [ABSTRACT FROM PUBLISHER]

Summary Objectives To assess off-treatment virological relapse rates and to determine the role of hepatitis B surface antigen (HBsAg) quantification in predicting virological relapse after stopping entecavir (ETV) treatment in patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB). Methods One hundred and twelve CHB patients for whom ETV was stopped in accordance with the Asian Pacific Association for the Study of the Liver guidelines stopping rules were enrolled. Patient HBsAg and HBV DNA levels were monitored every 4–12 weeks during ETV treatment and after ETV cessation. Post-treatment virological relapse was defined as a serum HBV DNA level of >10 000 copies/ml after stopping ETV treatment. Results The virological relapse rate at 52 weeks after stopping ETV was 48.2%. The post-treatment virological relapse rate was significantly higher in patients aged >50 years than in those aged <50 years ( p < 0.001), and the virological relapse rate was significantly lower in patients with an HBsAg level <2.0 log 10 IU /ml than in those with a level ≥2.0 log 10 IU /ml at ETV cessation ( p = 0.005). An HBsAg level of 2.5 log 10 IU/ml at HBeAg seroconversion was the optimal cut-off value for predicting post-treatment virological relapse ( p < 0.001). In those aged <50 years and with HBsAg ≤2.5 log 10 IU/ml at HBeAg seroconversion, the relapse rate was only 5%. In patients with HBsAg ≤2.5 log 10 IU/ml at HBeAg seroconversion, 52.4% achieved HBsAg levels ≤2.0 log 10 IU/ml at ETV cessation, while in those with HBsAg >2.5 log 10 IU/ml at HBeAg seroconversion, only 4.4% achieved this criterion. Conclusions HBsAg levels can help guide the timing of cessation of ETV treatment. HBsAg levels of 2.5 log 10 IU/ml at HBeAg seroconversion may be a useful marker to predict virological relapse after the cessation of ETV treatment in HBeAg-positive CHB patients. [ABSTRACT FROM AUTHOR]

Wheat's wild relatives are potential resources for the genetic improvement of common wheat quality. Novel high-molecular-weight glutenin subunits (HMW-GS) from Aegilops markgrafii were identified using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Three complete coding sequences of novel HMW-GS were cloned and sequenced. The lengths of these sequences, encoding 881, 847, and 644 amino acid residues, were 2649, 2571, and 1938 bp (designated as Cx1, Cx3, and Cy3), respectively. Sequence comparison showed that added SNPs and InDels were responsible for major variations in the new genes. Analysis of the deduced amino acid sequences revealed that the primary structures of the x- and y-type HMW-GS of Ae . markgrafii were similar to those of previously published HMW-GS. In particular, all new Cx subunits had higher molecular weights than the previously reported HMW-GS in Ae . markgrafii , which have potential value in improving bread quality. Phylogenetic analysis supported the information on the origin of the B genome in wheat. In conclusion, our study not only broadens our understanding of the genetics and phylogenetic knowledge of the HMW-GS protein family but also provides new insight into wheat breeding for end-use quality improvement. [ABSTRACT FROM AUTHOR]

Abstract: A novel class of chiral-amine-functionalized ionic liquids (CAFILs) has been synthesized efficiently from natural amino acids, and their structures have been determined by spectroscopic analysis and low temperature X-ray diffraction analysis. The CAFILs have been characterized by physical properties such as melting point, glass transition temperature, thermal degradation and specific rotation. NMR measurements indicate that the CAFILs may be promising alternatives in the field of chiral discrimination. [Copyright &y& Elsevier]

This work reports on the emergence of quantum Griffiths singularity (QGS) associated with the magnetic field induced superconductor-metal transition (SMT) in unconventional Nd&#95;{0.8}Sr&#95;{0.2}NiO&#95;{2} infinite layer superconducting thin films. The system manifests isotropic SMT features under both in-plane and perpendicular magnetic fields. Importantly, after scaling analysis of the isothermal magnetoresistance curves, the obtained effective dynamic critical exponents demonstrate divergent behavior when approaching the zero-temperature critical point B&#95;{c}^{*}, identifying the QGS characteristics. Moreover, the quantum fluctuation associated with the QGS can quantitatively explain the upturn of the upper critical field around zero temperature for both the in-plane and perpendicular magnetic fields in the phase boundary of SMT. These properties indicate that the QGS in the Nd&#95;{0.8}Sr&#95;{0.2}NiO&#95;{2} superconducting thin film is isotropic. Moreover, a higher magnetic field gives rise to a metallic state with the resistance-temperature relation R(T) exhibiting lnT dependence among the 2-10 K range and T^{2} dependence of resistance below 1.5 K, which is significant evidence of Kondo scattering. The interplay between isotropic QGS and Kondo scattering in the unconventional Nd&#95;{0.8}Sr&#95;{0.2}NiO&#95;{2} superconductor can illustrate the important role of rare region in QGS and help to uncover the exotic superconductivity mechanism in this system.

Microvirga flocculans CGMCC 1.16731 can degrade many cyano group-containing neonicotinoid insecticides. Here, its genome was sequenced, and a novel nitrile hydratase gene cluster was discovered in a plasmid. The NHase gene cluster ( pnhF ) has gene structure β-subunit 1, α-subunit, and β-subunit 2, which is different from previously reported NHase gene structures. Phylogenetic analysis of α-subunits indicated that NHases containing the three subunit (β1αβ2) structure are independent from NHases containing two subunits (αβ). pnhF was successfully expressed in Escherichia coli , and the purified PnhF could convert the nitrile-containing insecticide flonicamid to N -(4-trifluoromethylnicotinoyl)glycinamide. The enzymatic properties of PnhF were investigated using flonicamid as a substrate. Homology models revealed that amino acid residue β1-Glu56 may strongly affect the catalytic activity of PnhF. This study expands our understanding of the structures and functions of NHases and the enzymatic mechanism of the environmental fate of flonicamid.

Sulfoxaflor, a sulfoximine insecticide, could efficiently control many insect pests of sap-feeding. Microbial degradation of sulfoxaflor and the enzymatic mechanism involved have not been studied to date. A bacterial isolate JW2 that transforms sulfoxaflor to X11719474 was isolated and identified as Aminobacter sp. CGMCC 1.17253. Both the recombinant Escherichia coli strain harboring the Aminobacter sp. CGMCC 1.17253 nitrile hydratase (NHase) gene and the pure NHase acquired sulfoxaflor-degrading ability. Aminobacter sp. CGMCC 1.17253 NHase is a typical cobalt-containing NHase content of subunit α, subunit β, and an accessory protein, and the three-dimensional homology model of NHase was built. Substrate specificity tests showed that NHase catalyzed the conversion of acetamiprid, thiacloprid, indolyl-3-acetonitrile, 3-cyanopyridine, and benzonitrile into their corresponding amides, indicating its broad substrate specificity. This is the first report of the pure bacteria degradation of the sulfoxaflor residual in the environment and reveals the enzymatic mechanism mediated by Aminobacter sp. CGMCC 1.17253.

Flonicamid ( N -cyanomethyl-4-trifluoromethylnicotinamide, FLO), a novel selective systemic pyridinecarboxamide insecticide, effectively controls hemipterous pests. However, microbial degradation of flonicamid, along with the enzymatic mechanism, has not been studied. Here, bacterial isolate PG13, which converts flonicamid into 4-(trifluoromethyl)nicotinol glycine (TFNG) and N -(4-trifluoromethylnicotinoyl)glycinamide (TFNG-AM), was isolated and identified as Alcaligenes faecalis CGMCC 17553. The genome of CGMCC 17553 contained five nitrilases but no nitrile hydratase, and recombinant Escherichia coli strains harboring CGMCC 17553 nitrilase gene nitA or nitD acquired the ability to degrade flonicamid. Purified NitA catalyzed flonicamid into both TFNG and TFNG-AM, indicating dual functionality, while NitD could only produce TFNG-AM. Three-dimensional homology modeling revealed that aromatic amino acid residues in the catalytic pocket affected nitrilase activity. These findings further our understanding of the enzymatic mechanism of flonicamid metabolism in the environment and may help develop a potential bioremediation agent for the elimination of flonicamid contamination.

Variovorax is a metabolically diverse genus of plant growth-promoting rhizobacteria (PGPR) that engages in mutually beneficial interactions between plants and microbes. Unlike most PGPR, Variovorax cannot synthesize the phytohormone indole-3-acetic acid (IAA) via tryptophan. However, we found that Variovorax boronicumulans strain CGMCC 4969 can produce IAA using indole-3-acetonitrile (IAN) as the precursor. Thus, in the present study, the IAA synthesis mechanism of V. boronicumulans CGMCC 4969 was investigated. V. boronicumulans CGMCC 4969 metabolized IAN to IAA through both a nitrilase-dependent pathway and a nitrile hydratase (NHase) and amidase-dependent pathway. Cobalt enhanced the metabolic flux via the NHase/amidase, by which IAN was rapidly converted to indole-3-acetamide (IAM) and in turn to IAA. IAN stimulated metabolic flux via the nitrilase, by which IAN was rapidly converted to IAA. Subsequently, the IAA was degraded. V. boronicumulans CGMCC 4969 can use IAN as the sole carbon and nitrogen source for growth. Genome sequencing confirmed the IAA synthesis pathways. Gene cloning and overexpression in Escherichia coli indicated that NitA has nitrilase activity and IamA has amidase activity to respectively transform IAN and IAM to IAA. Interestingly, NitA showed a close genetic relationship with the nitrilase of the phytopathogen Pseudomonas syringae Quantitative PCR analysis indicated that the NHase/amidase system is constitutively expressed, whereas the nitrilase is inducible. The present study helps our understanding of the versatile functions of Variovorax nitrile-converting enzymes that mediate IAA synthesis and the interactions between plants and these bacteria. IMPORTANCE We demonstrated that Variovorax boronicumulans CGMCC 4969 has two enzymatic systems-nitrilase and nitrile hydratase/amidase-that convert indole-3-acetonitrile (IAN) to the important plant hormone indole-3-acetic acid (IAA). The two IAA synthesis systems have very different regulatory mechanisms, affecting the IAA synthesis rate and duration. The nitrilase was induced by IAN, which was rapidly converted to IAA; subsequently, IAA was rapidly consumed for cell growth. The nitrile hydratase (NHase) and amidase system was constitutively expressed and slowly but continuously synthesized IAA. In addition to synthesizing IAA from IAN, CGMCC 4969 has a rapid IAA degradation system, which would be helpful for a host plant to eliminate redundant IAA. This study indicates that the plant growth-promoting rhizobacterium V. boronicumulans CGMCC 4969 has the potential to be used by host plants to regulate the IAA level., (Copyright © 2018 American Society for Microbiology.)

Imidacloprid (IMI) is mainly metabolized via nitroreduction and hydroxylation pathways, which produce different metabolites that are toxic to mammals and insects. However, regulation of IMI metabolic flux between nitroreduction and hydroxylation pathways is still unclear. In this study, Pseudomonas putida was found to metabolize IMI to 5-hydroxy and nitroso IMI and was therefore used for investigating the regulation of IMI metabolic flux. The cell growth time, cosubstrate, dissolved oxygen concentration, and pH showed significant effect on IMI degradation and nitroso and 5-hydroxy IMI formation. Gene cloning and overexpression in Escherichia coli proved that P. putida KT2440 aldehyde oxidase mediated IMI nitroreduction to nitroso IMI, while cytochrome P450 monooxygenase (CYP) failed to improve IMI hydroxylation. Moreover, E. coli cells without CYP could hydroxylate IMI, demonstrating the role of a non-CYP enzyme in IMI hydroxylation. Thus, the present study helps to further understand the environmental fate of IMI and its underlying mechanism.

The design and synthesis of efficient receptors for tetrahedral oxyanions is an emerging field in supramolecular chemistry. Herein, we have developed a urea-like anion-recognizing motif, amidetriazole, which can be easily synthesized and derived and shows good solubility. A series of simple acyclic receptors were designed and synthesized to confirm the potential of amidetriazole for the construction of tetrahedral oxyanion receptors. This molecular platform can be used extensively for the construction of numerous receptor systems appended with functional groups, which opens the way to many applications in the field of supramolecular chemistry., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)