Theoretical study of above-threshold dissociation on diatomic molecules by using nonresonant intense laser pulses

The above-threshold dissociation of the ground state of a OH molecule under intense nonresonant laser pulses has been studied using the time-dependent Schr?dinger equation with discrete variable representation. The applied field is assumed as a two-color mixed nonresonant laser pulses which has the nonresonant frequency omega and the overtone 2omega. After modulating the relative phase factor between the omega and 2omega pulse, we extracted a three-photon absorption peak or a five-photon absorption peak in the ATD spectrum.     

Enzyme-based field-effect transistor for adenosine triphosphate (ATP) sensing.

Adenosine triphosphate (ATP) not only functions as an energy-carrier substance and an informative molecule, but also acts as a marker substance in studies of both bio-traces and cellular/tissular viability. Due to the importance of the ATP function for living organisms, in situ assays of ATP are in demand in various fields, e.g., hygiene. In the present study, we developed an ATP sensor that combines the selective catalytic activity of enzyme and the properties of an ion selective field effect transistor (ISFET). In this system, the ATP hydrolyrase, "apyrase (EC 3.6.1.5.)" is encased in a gel and mounted on a Ta(2)O(5) ISFET gate surface. When the enzyme layer selectively catalyzes the dephosphorylation of ATP, protons are accumulated at the gate because the enzymatic reaction produces H(+) as a byproduct. Based on the interfacial enzymatic reaction, the response from the ISFET is completely dependent upon the ATP concentration in the bulk solution. This device is readily applicable to practical in situ ATP measurement, e.g. hygienic usage.     

Face-selective [2]- and [3]rotaxanes: kinetic control of the threading direction of cyclodextrins

New [2]- and [3]pseudorotaxanes containing alpha-cyclodextrin (alpha-CDs) molecules as rotors and alkyl pyridinium derivatives as axles were prepared by a slipping process. The inclusion behavior of these rotaxanes was investigated by using one- and two-dimensional NMR spectroscopy. The methyl group at the 2-position of the pyridinium moiety at the end of each axle molecule was found to control the rates of threading of the alpha-CD onto the axle molecules. alpha-CD can approach axle molecules from a particular direction to form inclusion complexes. Axle molecules that contain a 2-methylpyridinium moiety at one end and a bulky stopper at the other end can regulate the direction of approach to give a [2]pseudorotaxane such as 2 b-alpha-CD. A [3]pseudorotaxane in which two alpha-CD molecules are arranged facing in the same direction at two stations of the tetracationic axle molecule was also obtained. These face-selective behaviors are dominated by kinetic processes rather than thermodynamic processes.     

Investigation of combustion modes and pressure of reflective shuttling detonation combustor

Detonation combustors are considered promising alternatives to conventional combustors because they offer high thermal efficiency and fast combustion. However, especially for the rotating detonation combustor, the theoretical propulsive performance has not been confirmed in experimental studies because the highly unsteady flow field hinders the measurements process. To understand the involved phenomena in more detail, a reflective shuttling detonation combustor (RSDC) with a rectangular combustion chamber was developed. The interior of the chamber can easily be visualized owing to its two-dimensional quality. Utilizing the RSDC, several combustion tests with gaseous ethylene and oxygen were conducted for different values of mass flow rates and equivalence ratios. Combustion modes from the tests were classified into four types based on the fast Fourier transform (FFT) analysis of the luminous intensity of the CH* self-luminescence images captured by a high-speed camera and a band pass filter. Simultaneously, the theoretical total pressure of a conventional isobaric combustor was compared to the static pressure measured at the bottom of the RSDC chamber. For the detonation modes, the ratio between experimentally measured static pressure and the theoretical pressure varied depending on the location in the chamber owing to the distribution of the time-averaged static pressure. Furthermore, the pressure ratio of the detonation modes was up to 18% lower than that of the deflagration mode potentially owing to the flow velocity induced by the detonation waves.     

Exploring effects of tensor force and its strength via neutron drops

The tensor-force effects on the evolution of spin-orbit splittings in neutron drops are investigated within the framework of the relativistic Hartree-Fock theory.For a fair comparison on the pure mean-field level,the results of the relativistic Brueckner-Hartree-Fock calculation with the Bonn A interaction are adopted as meta-data.Through a quantitative analysis,we certify that the π-psendovector(π-PV) coupling affects the evolutionary trend through the embedded tensor force.The strength of the tensor force is explored by enlarging the strength f_π of the π-PV coupling.It is found that weakening the density dependence of f_π is slightly better than enlarging it with a factor.We thus provide a semiquantitative support for the renormalization persistency of the tensor force within the framework of density functional theory.This will serve as important guidance for further development of relativistic effective interactions with particular focus on the tensor force.     

Highly Efficient,Catalytic Meerwein–Ponndorf–Verley Reduction with a Novel Bidentate Aluminum Catalyst

Double electrophilic activation of carbonyl groups allows a modern variant of the Meerwein–Ponndorf–Verley reduction to be carried out under mild conditions with bidentate catalyst 1 (see reaction). Various carbonyl substrates can be reduced efficiently at room temperature in CH₂Cl₂ with 2-propanol or sec-phenethyl alcohol in the presence of a catalytic amount of 1 . This system is also applicable to the Oppenauer oxidation of secondary alcohols to the corresponding ketones.     

Targeted 1,3-dipolar cycloaddition with acrolein for cancer prodrug activation

Cytotoxic anticancer drugs used in chemotherapy are often antiproliferative agents that preferentially kill rapidly growing cancer cells. Their mechanism relies mainly on the enhanced proliferation rate of cancer cells and is not genuinely selective for cancer cells. Therefore, these drugs can also significantly affect healthy cells. Prodrug therapy provides an alternative approach using a less cytotoxic form of anticancer drug. It involves the synthesis of inactive drug derivatives which are converted to an active form inside the body and, preferably, only at the site of cancerous tissues, thereby reducing adverse drug reaction (ADR) events. Herein, we demonstrate a prodrug activation strategy by utilizing the reaction between aryl azide and endogenous acrolein. Since acrolein is generally overproduced by most cancer cells, we anticipate our strategy as a starting point for further applications in mouse models with various cancers. Furthermore, cancer drugs that have had therapeutic index challenges might be reconsidered for application by utilizing our strategy.

Prodrug activation strategy by utilizing the reaction between aryl azide and endogenous acrolein that is generally overproduced by cancer cells.