Enhanced Anion Binding from Unusual Coordination Modes of Bis(thiourea) Ligands in Platinum Group Metal Complexes

Treatment of a range of bis(thiourea) ligands with inert organometallic transition‐metal ions gives a number of novel complexes that exhibit unusual ligand binding modes and significantly enhanced anion binding ability. The ruthenium(II) complex [Ru(η⁶‐p‐cymene)(κS,S′,N‐ L³ ?H)]⁺ ( 2 b ) possesses juxtaposed four‐ and seven‐membered chelate rings and binds anions as both 1:1 and 2:1 host guest complexes. The pyridyl bis(thiourea) complex [Ru(η⁶‐p‐cymeme)(κS,S′,N_py‐ L⁴ )]²⁺ ( 4 ) binds anions in both 1:1 and 1:2 species, whereas the free ligand is ineffective because of intramolecular NH???N hydrogen bonding. Novel palladium(II) complexes with nine‐ and ten‐membered chelate rings are also reported.     

Solubility of CO2 in the solvent system (water + monoethanolamine + triethanolamine)

This report presents a new set of values for the solubility of carbon dioxide in the solvent system {water (1) + monoethanolamine (2) + triethanolamine (3)} at T = (313.2, 333.2, 353.2, and 373.2) K and CO₂ partial pressures ranging (1.0 to 120) kPa. The results are specific to solvent systems with the following compositions: (i) ω₂ = 0.24, ω₃ = 0.06, (ii) ω₂ = 0.18, ω₃ = 0.12, (iii) ω₂ = 0.12, ω₃ = 0.18, (iv) ω₂ = 0.06, ω₃ = 0.24, and (v) ω₂ = 0, ω₃ = 0.30, where ω refers to the mass fraction of the component. The results fit the Deshmukh and Mather model well.     

Biocompatible copper(I) catalysts for in vivo imaging of glycans

The Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is the standard method for bioorthogonal conjugation. However, current Cu(I) catalyst formulations are toxic, hindering their use in living systems. Here we report that BTTES, a tris(triazolylmethyl)amine-based ligand for Cu(I), promotes the cycloaddition reaction rapidly in living systems without apparent toxicity. This catalyst allows, for the first time, noninvasive imaging of fucosylated glycans during zebrafish early embryogenesis. We microinjected embryos with alkyne-bearing GDP-fucose at the one-cell stage and detected the metabolically incorporated unnatural sugars using the biocompatible click chemistry. Labeled glycans could be imaged in the enveloping layer of zebrafish embryos between blastula and early larval stages. This new method paves the way for rapid, noninvasive imaging of biomolecules in living organisms.     

Trichoderma harzianum IOC-4038: A Promising Strain for the Production of a Cellulolytic Complex with Significant β-Glucosidase Activity from Sugarcane Bagasse Cellulignin

Sugarcane bagasse is an agroindustrial residue generated in large amounts in Brazil. This biomass can be used for the production of cellulases, aiming at their use in second-generation processes for bioethanol production. Therefore, this work reports the ability of a fungal strain, Trichoderma harzianum IOC-4038, to produce cellulases on a novel material, xylan free and cellulose rich, generated from sugarcane bagasse, named partially delignified cellulignin. The extract produced by T. harzianum under submerged conditions reached 745, 97, and 559 U L⁻¹ of β-glucosidase, FPase, and endoglucanase activities, respectively. The partial characterization of this enzyme complex indicated, using a dual analysis, that the optimal pH values for the biocatalysis ranged from 4.9 to 5.2 and optimal temperatures were between 47 and 54 °C, depending on the activity studied. Thermal stability analyses revealed no significant decrease in activity at 37 °C during 23 h of incubation. When compared to model strains, Aspergillus niger ATCC-16404 and Trichoderma reesei RutC30, T. harzianum fermentation was faster and its extract showed a better balanced enzyme complex, with adequate characteristics for its application in simultaneous saccharification and fermentation processes.     

CE‐ESI‐TOF/MS for human growth hormone analysis

CE is a powerful analytical tool used to separate intact biomolecules such as proteins. The coupling of CE with TOF/MS produces a very promising method that can be used to detect and identify proteins in different matrices. This paper describes an efficient, rapid, and simple CE‐ESI‐TOF/MS procedure for the analysis of endogenous human growth hormone and recombinant human growth hormone without sample preparation. Operational factors were optimized using an experimental design, and the method was successfully applied to distinguish human growth hormone and recombinant human growth hormone in unknown samples.     

Equilibrium solubility of carbon dioxide in (2-amino-2-methyl-1-propanol + piperazine + water)

In this work, a new set of values for the solubility of carbon dioxide in aqueous mixture containing different concentrations of 2-amino-2-methyl-1-propanol (AMP), a sterically-hindered amine, and piperazine (PZ), an activator, are presented. The results were carefully determined using a 1.0 dm³ stainless steel vapour-recirculation equilibrium cell at T = (313.2, 333.2, and 353.2) K, and pressures up to 152 kPa. The AMP concentrations in the ternary (solvent) mixture were (2 and 3) kmol · m^?3; those of PZ’s were (0.5, 1.0, and 1.5) kmol · m^?3. The measured equilibrium loading (solubility)/partial pressure pairs at different temperatures and concentration levels were generally consistent with the corresponding values correlated from the Kent–Eisenberg model that has been adapted for the system in the study, where the parameters of the models were determined using the results from this study and relevant data from literature.     

Asymptotic stability for Bresse systems

In this paper consider a vibrating system of Bresse type in a one-dimensional bounded domain with a nonlinear damping acting in the equation of the shear angle displacement, and nonlinear localized damping in other equations. We show the asymptotic stability without imposing conditions about the equal-speed wave propagation, using a method developed by Lasiecka and Tataru [9].     

Gaps in the number of generators of monomial Togliatti systems

Let $I_{d,n}?k[x_0,?,x_n]$ be a minimal monomial Togliatti system of forms of degree d. In [4], Mezzetti and Miró-Roig proved that the minimal number of generators $\mu (I_{d,n})$ of $I_{d,n}$ lies in the interval $[2n+1,\left(\begin{array}{c}n+d?1\\ n?1\end{array}\right)]$. In this paper, we prove that for $n\ge 4$ and $d\ge 3$, the integer values in $[2n+3,3n?1]$ cannot be realized as the number of minimal generators of a minimal monomial Togliatti system. We classify minimal monomial Togliatti systems $I_{d,n}?k[x_0,?,x_n]$ of forms of degree d with $\mu (I_{d,n})=2n+2$ or 3n (i.e. with the minimal number of generators reaching the border of the non-existence interval). Finally, we prove that for $n=4$, $d\ge 3$ and $\mu \in [9,\left(\begin{array}{c}d+3\\ 3\end{array}\right)]?\{11\}$ there exists a minimal monomial Togliatti system $I_{d,n}?k[x_0,?,x_n]$ of forms of degree d with $\mu (I_{n,d})=\mu$.     

Peptoids bearing tertiary amino residues in the n-alkyl side chains: synthesis of a potent inhibitor of Semaphorin 3A

A study on the preparation of N-alkylglycines (peptoids) that contain tertiary amino residues on the N-alkyl side chains is reported. The appropriate combination of the submonomer strategy with N-alkylglycine monomer couplings depending upon the structure of the N-alkyl side chain that must be incorporated into the peptoid is determinant for the efficiency of the synthetic pathway. The application of this strategy to the preparation of SICHI, an N-alkyglycine trimer containing tertiary amino residues in the three N-alkyl branches, and that has been identified as a potent Semaphorin 3A inhibitor, is presented.