Electrochemically-driven conformational shift in mono- and di-copper constrained macrotricyclic cyclen receptors

An electrochemical study of mono- and di-copper constrained cyclen macrotricycles is presented. Electrochemical data in DMF solution indicate that the reduction of dinuclear complexes occurs in two steps in the -0.4 to -0.8 V vs.AgCl/Ag potential range yielding CuII CuI and CuI CuI species further reduced to Cu metal at highly negative potentials. Mononuclear complexes are reduced in two steps to CuI and Cu metal. Electrochemical data suggest that reduction of both mononuclear and dinuclear complexes approach a square scheme involving electrochemically-driven conformational shifts for metal ions. The presence of endo- and exo-forms of the complexes are revealed by changes in the electrochemical response of the complexes in the presence of tetraethylammonium chloride, 1-azabicyclo[2.2.2]octane and diazabicyclo[2.2.2]octane competing ligands.     

Recognition of anions by polyammonium macrocyclic and cryptand receptors: Influence of the dimensionality on the binding behavior

Seven pairs of macrocyclic/cryptand polyamines, differing only in the added dimensionality, were selected and evaluated as receptors for anions in aqueous solution. The main differences on binding properties of protonated macrocycles and protonated cryptands as receptors for anions were analyzed through the association constants and structural data from the literature. Reported stepwise association constant values were critically evaluated on the basis of diagrams of log K_eff in function of pH, being K_eff the effective constant values.     

Slow quench dynamics of a one-dimensional Bose gas confined to an optical lattice

We analyze the effect of a linear time variation of the interaction strength on a trapped one-dimensional Bose gas confined to an optical lattice. The evolution of different observables such as the experimentally accessible on site particle distribution are studied as a function of the ramp time by using time-dependent numerical techniques. We find that the dynamics of a trapped system typically displays two regimes: For long ramp times, the dynamics is governed by density redistribution, while at short ramp times, local dynamics dominates as the evolution is identical to that of an homogeneous system. In the homogeneous limit, we also discuss the nontrivial scaling of the energy absorbed with the ramp time.     

Fluoride glass Raman fiber laser at 2185 nm

We report on the first Raman laser based on a fluoride glass optical fiber. The Raman fiber laser was pumped by a 9.6?WTm3+:silica CW fiber laser operating at a wavelength of 1940?nm. A maximum output power of 580?mW was measured at 2185.1?nm, corresponding to a frequency shift of 579?cm(-1) (17.37?THz). We observed a threshold power of 3.8?W and a low power slope efficiency of 29% with respect to the launched pump power. Using those results and the known fiber parameters, we estimated a Raman gain peak value of 3.52*10(-14)?m/W, which is lower than the previously reported values.     

The Metallic State of Doped Conjugated Polymers: ESR Studies

We present ESR results obtained on highly doped polyacetylene and polyphenylene which bring some light on the magnetic and electronic properties of these systems, which are commonly assimilated to metals. We analyze the existing experimental data in terms of coexistence of Curie and Pauli type behaviours, and we show that ESR in the metallic state can be used to gain information on the dynamic properties of the electronic system.     

Cyelisation of arylcarboxamidouracils. Synthesis of a new 4H-3,1-benz-oxazin-4-one. Use of mass spectrometry as a probe

The action of acetic anhydride on an anthranylcarboxamidouraeil led to a new 2-substituted 4H-3,1-benzoxazin-4-one with potential analgesic activity. Mass spectrometry has been used as a method lor structure confirmation and several fragmentation pathways were proposed. Furthermore, an additional probe was given by opening of the lactonic ring submitted to the action of aliphatic and aromatic primary amines.     

Analysis of extracted and volatile components in blackstrap molasses feed as candidate house fly attractants

House flies are a ubiquitous insect that have the potential to spread many diseases to humans and livestock. Managing house fly populations is accomplished by having desirable baits, traps, and killing agents. Most house fly baits are designed for outdoor use or limited indoor use, and have a foul odor that is not conducive to food preparatory and dining areas. Blackstrap molasses has long been used as a house fly bait, but it is sticky and viscous, making it difficult to handle. This study sought to identify compounds present in blackstrap molasses that might be attractive to house flies, and therefore, provide the public with an indoor bait that does not have an offensive smell and is easy to handle. Indoor bioassays with house flies using 50% blackstrap molasses diluted in deionized water, a hexane extract of blackstrap molasses, and deionized water, elicited 86.2%, 70.6%, and 13.8% responses, respectively. Hexane and diethyl ether extracts of blackstrap molasses produced a large number of compounds with widely differing organic structures including substituted phenols, nitrogen and oxygen heterocycles, carboxylic acids, and many other organic compounds.     

High‐Throughput Ligand Screening Enables the Enantioselective Conjugate Borylation of Cyclobutenones to Access Synthetically Versatile Tertiary Cyclobutylboronates

Cyclobutane rings are important in medicinal chemistry, yet few enantioselective methods exist to access this scaffold. In particular, cyclobutylboronates are receiving increasing attention in the literature due to the synthetic versatility of alkylboronic esters and the increasing role of boronic acids in drug discovery. Herein, a conjugate borylation of α‐alkyl,β‐aryl/alkyl cyclobutenones is reported leading to the first synthesis of enantioenriched tertiary cyclobutylboronates. Cyclobutanones with two stereogenic centers are obtained in good to high yield, with high enantioselectivity and diastereoselectivity. Vital to this advance are the development of a novel approach to α,β unsymmetrically disubstituted cyclobutenone substrates and the use of a high‐throughput chiral ligand screening platform. The synthetic utility of both the boronic ester and ketone functionalities is displayed, with remarkable chemoselectivity for either group being possible in this small ring scaffold.     

Cell Culture Tracking by Multivariate Analysis of Raw LCMS Data

Liquid chromatography mass spectrometry (LCMS) is a powerful technique that could serve to rapidly characterize cell culture protein expression profile and be used as a process monitoring and control tool. However, this application is often hampered by both the sample proteome and the LCMS signal complexities as well as the variability of this signal. To alleviate this problem, culture samples are usually extensively fractionated and pretreated before being analyzed by top-end instruments. Such an approach precludes LCMS usage for routine on-line or at-line application. In this work, by applying multivariate analysis (MA) directly on raw LCMS signals, we were able to extract relevant information from cell culture samples that were simply lyzed. By using the recombinant adenovirus production process as a model, we were able to follow the accumulation of the three major proteins produced, identified their accumulation dynamics, and draw useful conclusions from these results. The combination of LCMS and MA provides a simple, rapid, and precise means to monitor cell culture.