Application of microbiological sensors in fermentation processes

A review is presented of microbiological sensors which are composed of micro-organisms immobilized in a membrane and coupled to a sensing element. Conventional microbiological sensors such as those for biochemical oxygen demand (BOD), ethanol and acetic acid are discussed briefly. Novel sensors are then described. The sensor for carbon dioxide is based on a chemoautotrophic bacterium, that for alcohol on cell membranes of the acetic acid bacteria, Gluoconabacter suboxydans. Sensors for BOD carbon dioxide are based on thermophilic bacteria. Finally, a microbial field effect transistor sensor (FET) for alcohol sensor is described. For all the sensors, the ranges of linear response and their long-term stabilities are reported.     

Hoop‐Shaped Condensed Aromatic Systems: Synthesis and Structure of Iron– and Ruthenium–Hepta(organo)[60]fullerene Complexes

Potassium reduction of iron– and ruthenium–penta(organo)[60]fullerene complexes, [M(η⁵‐C₆₀R₅)(η⁵‐Cp)] ( 1 a : M=Fe, R=Ph; 1 b : M=Fe, R=Me; 1 c : M=Ru, R=Ph; 1 d : M=Ru, R=Me; Cp=C₅H₅) gave mono‐ and dianions of these complexes. Treatment of the dianion 1 a with α‐bromodiphenylmethane gave three different iron–hepta(organo)[60]fullerenes, [Fe{η⁵‐C₆₀Ph₅(CHPh₂)₂}(η⁵‐Cp)], as a mixture of regioisomers. All three compounds were fully characterized by physical methods, including X‐ray crystallography and electrochemical measurements. One of the three compounds contains a new hoop‐shaped condensed aromatic system.     

Collision-energy-resolved Penning ionization electron spectroscopy of bromomethanes (CH3Br, CH2Br2, and CHBr3) by collision with He*(2(3)S) metastable atoms

Ionization of bromomethanes (CH3Br, CH2Br2, and CHBr3) upon collision with metastable He*(2(3)S) atoms has been studied by means of collision-energy-resolved Penning ionization electron spectroscopy. Lone-pair (nBr) orbitals of Br4p characters have larger ionization cross sections than sigma(C-Br) orbitals. The collision-energy dependence of the partial ionization cross sections shows that the interaction potential between the molecule and the He*(2(3)S) atom is highly anisotropic around CH3Br or CH2Br2, while isotropic attractive interactions are found for CHBr3. Bands observed at electron energies of approximately 2 eV in the He*(2(3)S) Penning ionization electron spectra (PIES) of CH2Br2 and CHBr3 have no counterpart in ultraviolet (He I) photoionization spectra and theoretical (third-order algebraic diagrammatic construction) one-electron and shake-up ionization spectra. Energy analysis of the processes involved demonstrates that these bands and further bands overlapping with sigma(C-Br) or piCH2 levels are related to autoionization of dissociating (He+ - Br-) pairs. Similarly, a band at an electron energy of approximately 1 eV in the He*(2(3)S) PIES spectra of CH3Br has been ascribed to autoionizing Br** atoms released by dissociation of (unidentified) excited states of the target molecule. A further autoionization (S) band can be discerned at approximately 1 eV below the lone-pair nBr bands in the He*(2(3)S) PIES spectrum of CHBr3. This band has been ascribed to the decay of autoionizing Rydberg states of the target molecule (M**) into vibrationally excited states of the molecular ion. It was found that for this transition, the interaction potential that prevails in the entrance channel is merely attractive.     

Metastable ion study of organosilicon compounds part II—hexamethyldisiloxane

Unimolecular reactions of the metastable silicenium ion (CH₃)₃SiOSi(CH₃)₂ ⁺ generated by dissociative ionization of bexamethyldisiloxane were investigated by mass-analysed ion kinetic energy (PUKE) Spectrometry. The characteristic fragmentations observed were losses of CH₄ and (CH₃)₂Si?O molecules. Complete scrambling of all methyl groups prior to these reactions was found by investigating the MIKE spectra of deuterium labelled analogues (CD₃)₃SiOSi(CH₃)₂⁺ and (CH₃)₃SiOSi(CD₃)₃⁺. The loss of methane was accompanied by a large kinetic energy release (T_0.5 = 482 meV). The MIKE spectra of silicenium ions were compared with those of their carbon analogues. The most predominant reaction of metastable (CH₃)₃COC(CH₃)₃⁺ ion was the loss of CH₂?C(C H₃)₂ leading to protonated acetone. Significant differences between the ion fragmention characteristics of silicon and carbon compounds were found.     

Determination of phosphorus death profiles in semiconductor silicon by chemical etching and filament vaporization inductively-coupled plasma atomic emission spectrometry

Silicon slices are dissolved by anodizin and removal of the silica film by hydrofluoric acid. The phosphorus in the etching solution is determined by the filament vaporization technique and the depth of silicon is measured by determining the silicon content in the etching solution by conventional inductively-coupled plasma atomic emission spectrometry. A lower limit of 10¹⁸ phosphorus atoms cm^?3 can be determined by sectioning intervals of 30–50 nm.     

Temperature,humidity, and dimension dependence of the bending motion of ionomer‐based polymer actuators

This paper focuses on the effects of temperature, humidity, and dimensions on the displacement of ionomer‐based polymer actuators. The amount of displacement and velocities of the actuation strongly increased with increasing humidity and temperature. We attributed this behavior to a change in the Young's modulus (the stiffness) and ion conductivity based on water uptake. To evaluate the dependence of the velocity of the displacement on humidity and temperature, we examined three velocities (i.e. the initial, bending, and backtracking velocities). The observed increase in the bending velocity at higher relative humidity (RH) levels arises from an increase in the water uptake, which enhances ion conductivity and decreases the film stiffness. The ratio of the bending velocity to the backtracking velocity at higher RH decreased because of a drastic increase of the backtracking velocity at higher RH. This result would be explained by an increase in the ion conductivity accompanying a decrease in the stiffness. Furthermore, we compared the difference in the amount of displacement of the actuator using actuators of two widths (2 and 10 mm) at 30, 60, and 90% RH and at 25 °C. The difference in the width of the actuator did not completely affect the displacement. These results are reasonably explained by considering the amount of mobile ions per unit volume of the films of the actuators. Copyright © 2016 John Wiley & Sons, Ltd.     

Size Dependence of [n]Cycloparaphenylenes (n=5–12) in Electrochemical Oxidation

The oxidation processes of [n]cycloparaphenylenes ([n]CPPs) (n=5–12) were systematically investigated by cyclic and rotating disk electrode voltammetry. All CPPs underwent pseudo‐reversible two‐electron oxidation irrespective of ring size, forming the corresponding radical cations and then dications. The results were in sharp contrast to those observed for linear oligoparaphenylenes, which only undergo one‐electron oxidation. The difference in the first and second oxidation potentials in the CPP oxidation was affected by the ring size and became more significant as the decrease of CPP size. In other words, while the first oxidation from neutral CPP to the radical cation occurred faster as the size of CPP becomes smaller, the second oxidation from the radical cation to dication exhibited opposite size dependence.     

Photocurrent-generating properties of organometallic fullerene molecules on an electrode

Compact, rigid, five-legged fullerene derivatives C60R5Me and M(C60R5)Cp (M = Fe and Ru; R = C6H4COOH, C6H4C6H4COOH, and CH2COOH) were synthesized and arrayed on an indium-tin oxide (ITO) surface. These devices exhibit a respectable quantum yield with photocurrent generation up to 18%, and, more importantly, the direction of the photocurrent can be changed not only by the molecular structure itself but also by changing the geometric configuration of the photoactive acceptor (fullerene) and donor (metal atom) on the ITO surface.     

Diastereoselective addition of zincated hydrazones to alkenylboronates and stereospecific trapping of boron/zinc bimetallic intermediates by carbon electrophiles

Zincated hydrazones possessing a tert-butyl group on the zinc atom undergo addition to (E)- or (Z)-alkenylboronic acid pinacol esters to produce alpha-alkylated-gamma-boryl-gamma-zinciohydrazone intermediates with good to excellent diastereoselectivity (ds). The 1,1-organodimetallic intermediate possessing a boron atom and a zinc atom in the position gamma to the hydrazone group undergoes further C-C bond formation with a carbon electrophile to give a gamma-boryl hydrazone possessing several contiguous stereogenic centers with up to 99% ds. The (S)-1-amino-2-methoxymethylpyrrolidine hydrazone shows a high level of asymmetric induction in the addition/trapping sequence. Density functional theory calculations on the pathways of the addition reaction revealed a metallo-ene mechanism consisting of the formation of a pi complex between a zincated hydrazone and a vinylborane followed by a six-centered bond reorganization of a highly ordered boat conformation transition state. The calculations indicated that the use of the zinc atom together with the imine or hydrazone is the key for the success of the olefinic variant of the aldol reaction that has long been considered not to take place because of the endothermicity of the reaction and has never been examined with any seriousness by chemists. The steric repulsion caused by the bulky tert-butyl ligand on the zinc atom and the pinacol moiety of the vinylboronate substrates in the highly ordered transition structures gives rise to the observed high ds of the present carbozincation reaction.     

Modular synthesis of functionalized benzosiloles by tin-mediated cyclization of (o-Alkynylphenyl)silane

Trimethylstannyllithium promotes cyclization of (o-alkynylphenyl)silane into a 3-stannylbenzosilole, via addition to the triple bond followed by intramolecular cyclization in a cascade fashion. This intermediate can be functionalized with either electrophiles or nucleophiles to allow modular synthesis of 2,3-disubstituted benzosiloles. One of these compounds, a phenylene-bis(benzosilole) compound, shows electron drift mobility as high as 6 x 10-4 cm2/Vs in an amorphous film, making this class of compounds promising electronic materials for organic light emitting devices and organic photovoltaic cells.