Chemistry

Dangling Ends Perturb the Stability of RNA Duplexes Responsive to Surrounding Conditions
Unpaired terminal nucleotides (dangling ends) occur in various biologically important RNA structures. We studied the thermal stability of RNA duplexes with dangling ends under conditions that mimic those in cells. Dangling ends of one or two nucleotides stabilized a duplex up to approximately 2.7 kcal mol−1 in the absence of cosolutes. RNA duplexes with dangling purine nucleotides were mo...


Preparation of acid-resistant heavy fluorous tags for recycling in synthetic systems
Acid-resistant heavy fluorous tags, in which all three fluorous chains are tethered in a symmetric manner by carbon–carbon linkage, were designed and synthesized from ethyl crotonate. They were designed also to possess a reactive OH group at a central position, not only for conjugation with a target molecule but also for tag recycling. The tag with an alkyl spacer equipped the primary OH grou...
Determination of Aroclor 1260 in Soil Samples by Gas Chromatography with Mass Spectrometry with Solid-Phase Microextraction
A novel fast screening method was developed for the determination of polychlorinated biphenyls that are constituents of the commercial mixture, Aroclor 1260, in soil matrices by gas chromatography with mass spectrometry combined with solid-phase microextraction. Non-equilibrium headspace solid-phase microextraction with a 100 μm polydimethylsiloxane fiber was used to extract polychlorinated bi...


Ultra-trace-level determination of diquat and paraquat residues in surface and drinking water using ion-pair liquid chromatography with tandem mass spectrometry: A comparison of direct injection and solid-phase extraction methods
Direct injection and solid-phase extraction methods for the determination of diquat and paraquat in surface and drinking water were developed using liquid chromatography with tandem mass spectrometry. The signal intensities of analytes based on six ion-pairing reagents were compared with each other and 12.5 mM nonafluoropentanoic acid was selected as the best suited amongst them. A clean-up met...
Analysis of phytosterols and phytostanols in enriched dairy products by Fast gas chromatography with mass spectrometry
A fast gas chromatography with mass spectrometry method for plant sterols/stanols analysis was developed, using a short capillary gas chromatography column (10 m x 0.1 mm internal diameter x 0.1 μm film thickness) coated with 5% diphenylpolysiloxane. A silylated mixture of the main plant sterols/stanols standards (β-sitosterol, campesterol, stigmasterol, campestanol, sitostanol) was well sepa...


Prediction of Compressional and Shear Slowness from Conventional Well Log Data: Using Intelligent Systems
Compressional slowness (DTCO) and shear slowness (DTSM) are two fundamental parameters that have many applications in petrophysical, geophysical, and geomechanical operations. These two parameters can be obtained using a dipole sonic imaging tool, but unfortunately this tool is run in just a few wells of a field. Therefore, it is important to predict compressional and shear slowness indirectly ...
Halogen exchange by reaction of CpRu(Cl)(PPh3)2 with MeC(O)X (X = Br, I) and its mechanistic study
The treatment of CpRu(Cl)(PPh3)2 with MeC(O)X offers a very convenient procedure for the synthesis of CpRu(X)(PPh3)2. The proposed mechanism involves an intermediate produced by the concerted liberation of PPh3 by the incoming MeC(O)X and the subsequent subtraction of the X atom by the Ru atom to form a radical pair....

An efficient method to synthesize chlorosilanes from hydrosilanes
An efficient, highly selective and productive synthesis of chlorosilanes from hydrosilanes is reported. Ceramic spheres were added to chlorination reaction systems and found to greatly increase the efficiency and yields of the reactions. PhSiH2Cl, PhSiHCl2, PhSiCl3, Ph2SiHCl, Ph2SiCl2, PhMeSiHCl and PhMeSiCl2 were synthesized from the corresponding hydrosilanes in only a few hours with yields t...
Chiral Carbonaceous Nanotubes Containing Twisted Carbonaceous Nanoribbons, Prepared by the Carbonization of Chiral Organic Self-Assemblies
Single-handed helical silica nanotubes containing chiral organic self-assemblies were prepared by using a supramolecular templating approach. After carbonization and the removal of the silica, single-handed helical carbonaceous nanotubes that contained twisted carbonaceous nanoribbons were obtained. It is believed that the nanotubes formed as a result of the adsorption of low-molecular-weight g...

PEG600-Carboxylates as Efficient Reusable Reaction Media and Acylating Agents for the Resolution of sec-Alcohols
Herein is presented a simple, attractive, and reusable methodology for one-pot resolution/separation of free sec-alcohols with enantiomeric excess (ee) values over 90 % by the combination of sustainable acylating agents/solvents (polyethylene glycol derivatives) and an easily available and common biocatalyst (Candida antarctica lipase B, or CAL B) under irreversible conditions, along with a...
Lithium–Air Oxygen Shuttle Battery with a ZrO2-Based Ion-Conducting Oxide Electrolyte
A lithium–air battery based on the concept of an “oxygen shuttle” with a calcium-stabilized ZrO2 electrolyte is described. The observed open-circuit voltage and discharge capacity are 1.81 V and 2179 mAh per gram of lithium, respectively, at 1073 K. When considering the transport number of an oxide ion at P O 2 in an anode chamber, the observed open-circuit voltage is reasonable...

Au–Co3O4/C as an Efficient Electrocatalyst for the Oxygen Evolution Reaction
Carbon black that is introduced into Co3O4 will reduce the overpotential of the oxygen evolution reaction. By adding Au, the Co3O4/C catalyst exhibits superior electrochemical activity and excellent stability for the oxygen evolution reaction. The catalyst with a weight ratio of Au to Co3O4 of 1:3 gives the best performance. After loading with Au, the binding energy value of Co 2p has a posit...
In-Cell NMR and EPR Spectroscopy of Biomacromolecules
The dream of cell biologists is to be able to watch biological macromolecules perform their duties in the intracellular environment of live cells. Ideally, the observation of both the location and the conformation of these macromolecules with biophysical techniques is desired. The development of many fluorescence techniques, including superresolution fluorescence microscopy, has significantly e...
The Hydrophobic Effect Revisited—Studies with Supramolecular Complexes Imply High-Energy Water as a Noncovalent Driving Force
Traditional descriptions of the hydrophobic effect on the basis of entropic arguments or the calculation of solvent-occupied surfaces must be questioned in view of new results obtained with supramolecular complexes. In these studies, it was possible to separate hydrophobic from dispersive interactions, which are strongest in aqueous systems. Even very hydrophobic alkanes associate significantly...
Carbon-Monoxide-Releasing Molecules for the Delivery of Therapeutic CO In Vivo
The development of carbon-monoxide-releasing molecules (CORMs) as pharmaceutical agents represents an attractive and safer alternative to administration of gaseous CO. Most CORMs developed to date are transition-metal carbonyl complexes. Although such CORMs have showed promising results in the treatment of a number of animal models of disease, they still lack the necessary attributes for clinic...