Pd(II)-Catalyzed Benzimidazole-Assisted Annulation of 3-(1H-Benzo[d]imidazol-2-yl)-2H-chromen-2-one: Access to Imidazo[1,2-a]chromeno[3,4-c]pyridine

Palladium-catalyzed [4+2] oxidative annulation of coumarin-benzimidazoles with olefins for the synthesis of polycyclic aromatic hydrocarbons have been achieved. This synthetic protocol gives access to a wide range of structurally distinct imidazo[1,2-a]chromeno[3,4-c]pyridines in moderate to good yield with wide functional group tolerance. Further, photophysical properties of annulated scaffolds have been examined, which discloses their interesting solvatochromic emission behaviors.     

Synthesis of 2D Germanane (GeH): a New,Fast, and Facile Approach

Germanane (GeH), a germanium analogue of graphane, has recently attracted considerable interest because its remarkable combination of properties makes it an extremely suitable candidate to be used as 2D material for field effect devices, photovoltaics, and photocatalysis. Up to now, the synthesis of GeH has been conducted by substituting Ca by H in a β‐CaGe₂ layered Zintl phase through topochemical deintercalation in aqueous HCl. This reaction is generally slow and takes place over 6 to 14 days. The new and facile protocol presented here allows to synthesize GeH at room temperature in a significantly shorter time (a few minutes), which renders this method highly attractive for technological applications. The GeH produced with this method is highly pure and has a band gap (E_g) close to 1.4 eV, a lower value than that reported for germanane synthesized using HCl, which is promising for incorporation of GeH in solar cells.     

Molecular dynamics simulation of the density and surface tension of water by particle-particle particle-mesh method

In this work, molecular dynamics simulation is performed to study the density and surface tension of water for a range of temperatures from 300 to 600 K. The extended simple point charge interaction potential for water is used. The particle-particle particle-mesh method, which automatically includes untruncated long-range terms, is used for the Lennard-Jones and the Coulombic terms. The results show that the long-range correction for the Lennard-Jones term is very important for the calculation of surface tension. It is found that the calculated density and surface tension of water fit well with experimental data for temperatures less than 500 K. Near the critical temperature, the simulation results are off from the experimental data.     

Novel synthesis of highly functionalized pyrazolines and pyrazoles by triphenylphosphine-mediated reaction of dialkyl azodicarboxylate with allenic esters

[reaction: see text] Reaction of the Huisgen zwitterion, derived from triphenylphosphine and dialkyl azodicarboxylate, with allenic esters affords highly functionalized pyrazolines and pyrazoles. The crystal structure of pyrazoline derivative 7a showed extensive C-H...O interactions. Pyrazole formation proceeds via a novel nitrogen to carbon migration of the carboalkoxy group.     

Design and Evaluation of an Optimal Controller for Simultaneous Saccharification and Fermentation Process

Ethanol from corn is produced using dry grind corn process in which simultaneous saccharification and fermentation (SSF) is one of the most critical unit operations. In this work an optimal controller based on a previously validated SSF model was developed by formulating the SSF process as a Bolza problem and using gradient descent methods. Validation experiments were performed to evaluate the performance of optimal controller under different process disturbances that are likely to occur in practice. Use of optimal control algorithm for the SSF process resulted in lower peak glucose concentration, similar ethanol yields (13.38±0.36% v/v and 13.50±0.15% v/v for optimally controlled and baseline experiments, respectively). Optimal controller improved final ethanol concentrations as compared to process without optimal controller under conditions of temperature (13.35±1.28 and 12.52±1.19% v/v for optimal and no optimal control, respectively) and pH disturbances (12.65±0.74 and 11.86±0.49% v/v for optimal and no optimal control, respectively). Cost savings due to lower enzyme usage and reduced cooling requirement were estimated to be up to $1 million for a 151 million L/yr (40 million gal/yr) dry grind plant.     

Application of Doehlert design in optimizing the determination of degraded products of nerve agents by ion-pair liquid chromatography electrospray ionization tandem mass spectrometry

A qualitative method was developed for the determination of degraded products of nerve agents by using ion-pair liquid chromatography electrospray ionization tandem mass spectrometry (IP-LC-ESI-MS(n)). Generally, alkylphosphonic acids (APAs) and O-alkyl alkylphosphonic acids (AAPAs) give deprotonated molecular ion [M-H](-) in negative mode. Interestingly, first time we obtained the molecular radical anion [M](.-) of phosphonic acids in negative mode by using tri-n-butyl amine as an ion-pairing agent. We interpreted this observation as an indication of electrochemical reduction of phosphonic acids in electrospray needle. Three variables such as sheath gas flow, electrospray needle voltage and pH of the mobile phase were investigated to enhance the molecular radical anion [M](.-) signal of each analyte. The Doehlert design was used to obtain the region in which the optimum value of such variables is simultaneously achieved. Limit of detection achieved was 0.5 microg mL(-1) for AAPAs and 10 microg mL(-1) for APAs. Excellent precision was observed with less than 8.61% RSD. Finally, the method was applied for the detection of ethyl methylphosphonic in aqueous extract of soil sample.     

A simple extrusion method for the synthesis of aligned silica nanowires using the template of a rigid surfactant mesophase

Long range alignment of silica nanowires has been accomplished by extrusion of a novel surfactant mesophase prior to silica synthesis.     

Determination of oxytocin in milk of cows administered oxytocin

To address people's concerns of exogenous oxytocin (OT) administration to lactating bovines, a study was undertaken to (a) establish an enzyme immunoassay (EIA) for OT determination in milk, (b) quantify OT in milk of cows administered OT, and (c) study influence of pasteurization on OT stability in milk. A sensitive EIA validated according to the criteria of European Union—Decision 2002/657/EC was developed for OT in skim milk in an analytical range of 10-250 pg mL⁻¹ with a decision limit (CCα) of 30 pg mL⁻¹ and detection capability (CCβ) of 41.5 pg mL⁻¹. Milk samples collected from cows (n = 38) administered either 25 or 50 IU OT prior to milking were investigated for the presence of OT. There was no significant difference among both groups with the mean concentrations of OT being 15.8 and 14.9 pg mL⁻¹ for cows subjected to 25 and 50 IU OT administration, respectively. The OT levels in skim milk of control cows (n = 30; untreated) were basal (around 10 pg mL⁻¹). All the analyzed milk samples were below the CCα value of 30 pg mL⁻¹. Pasteurization of OT spiked milk samples at different temperature and sample holding conditions reduced the immunological activity of OT to 43% at 110 °C. However, no further decline occurred in the immunological activity with increased pasteurization temperature and time. It was concluded that the milk OT concentrations after OT administrations were minimal and below the assay decision limit. However, OT was quite stable to pasteurization in OT spiked milk.     

The significance of the alkene size and the nature of the metal ion in metal-alkene complexes: a theoretical study

Cation interactions with π-systems are a problem of outstanding contemporary interest and the nature of these interactions seems to be quite different for transition and main group metal ions. In this paper, we have systematically analyzed the contrast in the bonding of Cu(+) and main group metal ions. The molecular structures and energetics of the complexes formed by various alkenes (A = C(n)H(2n), n = 2-6; C(n)H(2n- 2), n = 3-8 and C(n)H(2n + 2), n = 5-10) and metal ions (M = Li(+), Na(+), K(+), Ca(2+), Mg(2+), Cu(+) and Zn(2+)) are investigated by employing ab initio post Hartree-Fock (MP2/6-311++G**) calculations and are reported in the current study. The study, which also aims to evaluate the effect of the size of the alkyl portion attached to the π-system on the complexation energy, indicates a linear relationship between the two. The decreasing order of complexation energy with various metal ion-alkene complexes follows the order Zn(2+)-A > Mg(2+)-A > Ca(2+)-A > Cu(+)-A > Li(+)-A > Na(+)-A > K(+)-A. The increased charge transfer and the electron density at (3,-1) intermolecular bond critical point corroborates well with the size of the π-system and the complexation energy. The observed deviation from the linear dependency of the Cu(+)-A complexes is attributed to the dπ→π* back bonding interaction. An energy decomposition analysis via the reduced variational space (RVS) procedure was also carried out to analyze which component among polarization, charge transfer, coulomb and exchange repulsion contributes to the increase in the complexation energy. The RVS results suggest that the polarization component significantly contributes to the increase in the complexation energy when the alkene size increases.