Specific heat functions for the orthorhombic Nd3+ in scheelite type of crystals

Nd3+ doped scheelite type of crystals have attracted extensive interests because of their applications in solid state lasers, as well as upconversion luminescence and magneto-optical and magnetic properties. Usually, these properties are closely related to the local structures and properties of the Nd3+ impurities in the hosts. Since information about electronic states and local structures of the impurity Nd3+ in the scheelite crystals would be helpful to the understanding of the properties of these materials, theoretical investigations on the specific heat functions and the local structures for these Nd3+ centers are of significance.     

Laser Induced Lowest Triplet State Properties of Dibenzothiophene in Solution

Laser induced triplet state lifetimes are measured in the presence of air and for oxygen, air, argon saturated, and vacuum degassed solution of dibenzothiophene in solution at room temperature by triplet decay, including the prompt and p-type delayed fluorescence. The results are discussed and compared to those of molecules with the same symmetry.     

Labeling bombesin-like peptide with <Superscript>99m</Superscript>Tc via hydrazinonicotinamide: description of optimized radiolabeling conditions

Bombesin (BNN)-like peptides have very high binding affinity for the gastrin-releasing peptide (GRP) receptor. The goal of the current study was to optimize the labeling conditions of a new ^99mTc-radiolabeled BNN-like peptide based on the bifunctional chelating ligand HYNIC using different co-ligands (EDDA and tricine). The radiolabeling conditions (pH, amount of co-ligand, amount of stannous chloride, temperature and reaction time) for newly-formed ^99mTc-tricine-HYNIC-Q-Litorin and ^99mTc-EDDA-HYNIC-Q-Litorin were optimized and evaluated by RHPLC and RTLC. Radiochemical yields for ^99mTc-tricine-HYNIC-Q-Litorin and ^99mTc-EDDA-HYNIC-Q-Litorin were 98.0 ± 1.7 and 97.5 ± 2.5%, respectively. When EDDA was used as co-ligand, the labeling of ^99mTc-EDDA-HYNIC-Q-Litorin was optimal in the following reaction mixture: HYNIC-peptide: EDDA: 10 μg/5 mg, pH 3, SnCl₂ concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min. Besides, the optimum conditions were HYNIC-peptide:tricine: 10 μg/50 mg, pH 5, SnCl₂ concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min for preparing ^99mTc-tricine-HYNIC-Q-Litorin. The manufactured ^99mTc-HYNIC-Q-Litorin conjugates may offer new possibilities for imaging cancer cells expressing bombesin receptors.     

Preparation and biodistribution of [<Superscript>131</Superscript>I]linezolid in animal model infection and inflammation

Linezolid is the first of new class of antibiotics, the oxazolidinones, and exhibits activity against many gram-positive organisms, including vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus, and penicillin-resistant Streptococcus pneumoniae. Aim of the study: Linezolid was to label with I-131 and potential of the radiolabeled antibiotic was to investigate in inflamed rats with S. aureus (S. aureus) and sterile inflamed rats with turpentine oil. Linezolid was labeled with I-131 by iodogen method. Biodistribution of [¹³¹I]linezolid was carried out in bacterial inflamed and sterile inflamed rats. Radiolabeling yield of [¹³¹I]linezolid was determined as 85 ± 1% at pH 2. After injecting of [¹³¹I]linezolid into bacterial inflamed and sterile inflamed rats, radiolabeled linezolid was rapidly removed from the circulation via the kidneys. Binding of [¹³¹I]linezolid to bacterial inflamed muscle (T/NT = 77.48 at 30 min) was five times higher than binding to sterile inflamed muscle (T/NT = 14.87 at 30 min) of rats. [¹³¹I]linezolid showed good localization in bacterial inflamed tissue. It was demonstrated that [¹³¹I]linezolid can be used to detect S. aureus inflammation in rats.     

Photophysical properties of 5H-dibenzo(a,d)cyclohepten-5-one in different solutions

A number of photophysical properties of 5H-dibenzo(a,d)cyclohepten-5-one have been measured for the first time including the prompt and P-type delayed fluorescence, and triplet-triplet absorption. Decay parameters, for the triplet-state of this molecule, have also been measured in different quenching conditions. The results are discussed and compared for those of similar molecules.     

Binding energy of the donor impurities in GaAs-Ga_(1-x)Al_xAs quantum well wires with Morse potential in the presence of electric and magnetic fields

The behavior of a donor in the GaAs–Ga_(1-x)Al_xAs quantum well wire represented by the Morse potential is examined within the framework of the effective-mass approximation. The donor binding energies are numerically calculated for with and without the electric and magnetic fields in order to show their influence on the binding energies. Moreover, how the donor binding energies change for the constant potential parameters(De, re, and a) as well as with the different values of the electric and magnetic field strengths is determined. It is found that the donor binding energy is highly dependent on the external electric and magnetic fields as well as parameters of the Morse potential.     

Towards single-microorganism detection using surface-enhanced Raman spectroscopy

The identification and discrimination of microorganisms is important not only for clinical reasons but also for pharmaceutical clean room production and food-processing technology. Vibrational spectroscopy such as IR, Raman, and surface-enhanced Raman scattering (SERS) can provide a rapid ‘fingerprint’ on the chemical structure of molecules and is used to obtain a ‘fingerprint’ from microorganisms as well. Because of the requirement that a single bacterium cell and noble metal nanoparticles must be in close contact and the lack of a significant physical support to hold nanoparticles around the single bacterium cell, the acquisition of SERS spectra for a single bacterium using colloidal nanoparticles could be a challenging task. The feasibility of SERS for identification down to a single bacterium is investigated. A Gram-negative bacterium, Escherichia coli, is chosen as a model for the investigation. Because the adsorption of silver nanoparticles onto the bacterial cell is an exclusive way for locating nanoparticles close to the bacterium cell, the absorption characteristics of silver nanoparticles with different surface charges are investigated. It is demonstrated that the citrate-reduced colloidal silver solution generates more reproducible SERS spectra. It is found that E. coli cells aggregate upon mixing with silver colloidal solution, and this may provide an additional benefit in locating the bacterial cell under a light microscope. It is also found that a laser wavelength in the UV region could be a better choice for the study due to the shallow penetration depth. It is finally shown that it is possible to obtain SERS spectra from a single cell down to a few bacterial cells, depending on the aggregation properties of bacterial cells for identification and discrimination.     

Infrared spectroscopic and gravimetric studies on the cyclopropylaminemetal(II) tetracyanonickellate(II) host–aromatic guest systems

The host complexes M(Cyclopropylamine)₂Ni(CN)₄ (M = Co or Cd) have been prepared in powder form. The spectral data suggest that the structures of these compounds are similar to those of the Hofmann-type hosts. The absorption and the liberation processes of the aromatic guests (benzene, toluene, 1,2-dichlorobenzene, o-xylene, m-xylene and p-xylene) in these hosts have been examined at room temperature by gravimetric and spectroscopic measurements. The desorption of the benzene guest against time has been measured. The host structures do not change on inclusion and liberation of the guest. The host compounds have been suggested as sorbents for isomeric separations.     

New Bis(thio)-, Tris(thio)-, and Tetrakis(thio)-substituted Quinones from the Reactions of p-Chloranil with Some Thiols and Dithiols

p-Chloranil (1), when reacted with different thiol compounds, namely 1-buthylthiol, cyclohexylthiol, and 2,2-oxydiethanethiol in ethanol in the presence of Na ₂ CO ₃ , yielded the corresponding S-substituted quinone derivatives.