Aziridinyl-substituted benzo-1,4-quinones: A preliminary investigation on the theoretical and experimental studies of their structure and spectroscopic properties

2017 ◽  
Vol 178 ◽  
pp. 136-141
Author(s):  
Jonas Šarlauskas ◽  
Jelena Tamulienė ◽  
Narimantas Čėnas
Keyword(s):  
Preliminary Investigation ◽  
Experimental Studies ◽  
Spectroscopic Properties

scholarly journals Spectroscopic Properties of Two 5′-(4-Dimethylamino)Azobenzene Conjugated G-Quadruplex Forming Oligonucleotides

2020 ◽  
Vol 21 (19) ◽  
pp. 7103
Author(s):  
Concetta Imperatore ◽  
Antonio Varriale ◽  
Elisa Rivieccio ◽  
Angela Pennacchio ◽  
Maria Staiano ◽  
...  
Keyword(s):  
Fluorescence Spectroscopy ◽  
Gel Electrophoresis ◽  
Preliminary Investigation ◽  
Spectroscopic Properties ◽  
Structural Behavior ◽  
Fluorescence Studies ◽  
Azobenzene Moiety ◽  
G Quadruplex ◽  
Ethanol Blends ◽  
Hiv 1

The synthesis of two 5′-end (4-dimethylamino)azobenzene conjugated G-quadruplex forming aptamers, the thrombin binding aptamer (TBA) and the HIV-1 integrase aptamer (T30695), was performed. Their structural behavior was investigated by means of UV, CD, fluorescence spectroscopy, and gel electrophoresis techniques in K+-containing buffers and water-ethanol blends. Particularly, we observed that the presence of the 5′-(4-dimethylamino)azobenzene moiety leads TBA to form multimers instead of the typical monomolecular chair-like G-quadruplex and almost hampers T30695 G-quadruplex monomers to dimerize. Fluorescence studies evidenced that both the conjugated G-quadruplexes possess unique fluorescence features when excited at wavelengths corresponding to the UV absorption of the conjugated moiety. Furthermore, a preliminary investigation of the trans-cis conversion of the dye incorporated at the 5′-end of TBA and T30695 showed that, unlike the free dye, in K+-containing water-ethanol-triethylamine blend the trans-to-cis conversion was almost undetectable by means of a standard UV spectrophotometer.

scholarly journals Molecular Interpretation of Pharmaceuticals’ Adsorption on Carbon Nanomaterials: Theory Meets Experiments

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 642 ◽  
Author(s):  
Daniele Veclani ◽  
Marilena Tolazzi ◽  
Andrea Melchior
Keyword(s):  
Density Functional ◽  
Carbon Nanomaterials ◽  
Experimental Studies ◽  
Md Simulations ◽  
Spectroscopic Properties ◽  
Pharmaceutical Drugs ◽  
Mechanical Methods ◽  
Adsorption Processes ◽  
Carbon Based Nanomaterials

The ability of carbon-based nanomaterials (CNM) to interact with a variety of pharmaceutical drugs can be exploited in many applications. In particular, they have been studied both as carriers for in vivo drug delivery and as sorbents for the treatment of water polluted by pharmaceuticals. In recent years, the large number of experimental studies was also assisted by computational work as a tool to provide understanding at molecular level of structural and thermodynamic aspects of adsorption processes. Quantum mechanical methods, especially based on density functional theory (DFT) and classical molecular dynamics (MD) simulations were mainly applied to study adsorption/release of various drugs. This review aims to compare results obtained by theory and experiments, focusing on the adsorption of three classes of compounds: (i) simple organic model molecules; (ii) antimicrobials; (iii) cytostatics. Generally, a good agreement between experimental data (e.g. energies of adsorption, spectroscopic properties, adsorption isotherms, type of interactions, emerged from this review) and theoretical results can be reached, provided that a selection of the correct level of theory is performed. Computational studies are shown to be a valuable tool for investigating such systems and ultimately provide useful insights to guide CNMs materials development and design.

Experimental Studies of the Mental Speed of Schizophrenics

1958 ◽  
Vol 104 (437) ◽  
pp. 1130-1135 ◽  
Author(s):  
Anne Broadhurst
Keyword(s):  
Problem Solving ◽  
Marked Improvement ◽  
Preliminary Investigation ◽  
Experimental Studies ◽  
Normal Subjects ◽  
Extended Practice ◽  
Schizophrenic Patients ◽  
Problem Solving Task

In this paper, a further examination is made of the finding that schizophrenics, given a problem-solving task to measure mental speed, showed marked improvements attributable to practice (4).Preliminary investigation suggested the importance of the effects of both practice and drugs on speed of problem solving. The latter is reported elsewhere (4). There appears in the literature to be agreement that marked improvement is shown by schizophrenic patients after practice, but Huston and Shakow (11, 12) for example, give evidence that this improvement is even more marked for schizophrenics than it is for normals while Hunt and Cofer (9) report the contrary. Huston and Shakow also raise the question of whether or not it is possible, by very extended practice, to bring the performance of schizophrenics to the level of perfection reached by normal subjects after practice. Clarification of these points is necessary.

scholarly journals Transfer Reactions As a Tool in Nuclear Astrophysics

2021 ◽  
Vol 8 ◽  
Author(s):  
Faïrouz Hammache ◽  
Nicolas de Séréville
Keyword(s):  
Cross Sections ◽  
Transfer Reaction ◽  
Nuclear Reactions ◽  
Experimental Studies ◽  
Nuclear Astrophysics ◽  
Spectroscopic Properties ◽  
Reaction Rates ◽  
Theoretical Concept ◽  
Reaction Method ◽  
Basic Features

Nuclear reaction rates are one of the most important ingredients in describing how stars evolve. The study of the nuclear reactions involved in different astrophysical sites is thus mandatory to address most questions in nuclear astrophysics. Direct measurements of the cross-sections at stellar energies are very challenging–if at all possible. This is essentially due to the very low cross-sections of the reactions of interest (especially when it involves charged particles), and/or to the radioactive nature of many key nuclei. In order to overcome these difficulties, various indirect methods such as the transfer reaction method at energies above or near the Coulomb barrier are used to measure the spectroscopic properties of the involved compound nucleus that are needed to calculate cross-sections or reaction rates of astrophysical interest. In this review, the basic features of the transfer reaction method and the theoretical concept behind are first discussed, then the method is illustrated with recent performed experimental studies of key reactions in nuclear astrophysics.

Thermospheric heating away from the auroral oval during geomagnetic storms

1992 ◽  
Vol 70 (7) ◽  
pp. 544-552 ◽  
Author(s):  
A. G. Burns ◽  
T. L. Killeen ◽  
R. G. Roble
Keyword(s):  
Geomagnetic Storms ◽  
Preliminary Investigation ◽  
Experimental Studies ◽  
Auroral Oval ◽  
Long Tail ◽  
Temperature Changes ◽  
Model Predictions ◽  
Latitude Region ◽  
Region Ii ◽  
Iv Model

Model predictions indicate that the high-latitude thermosphere near the F2 peak undergoes strong heating during geomagnetic storms. Experimental studies at middle and equatorial latitudes have indicated that heating occurs during geomagnetic storms, although the overall morphology of these temperature changes is not clear. In this paper we use data from the DE-2 (dynamics explorer) satellite to study this morphology at middle and high latitudes, and then use a simulation of the November 24, 1982 storm, by the NCAR–TIGCM, to compare model output and data on a "one-on-one" basis for an individual orbit in the middle of this storm. Agreement between model and data is good in the winter hemisphere, so we use a thermodynamic diagnostic processor to make a preliminary investigation of the mechanisms by which geomagnetic storms cause temperature increases at lower latitudes. The major conclusions from this work are (i) unlike compositional changes, thermospheric temperature changes do not display a long "tail" into the post-midnight, mid-latitude region; (ii) the pattern of heating during geomagnetic storms is complex, a result of the complicated physical processes that occur during geomagnetic storms; (iii) heating due to advection is approximately balanced by expansion of the gas and downward heat conduction in the postmidnight region; (iv) model predictions for this storm indicate that the greatest temperature increase at 40° N is seen in the dawn sector; (v) early in the storm the strongest compressional heating at latitudes near 40° N is found in the premidnight region, where parcels of air are slowed by sunward ion convection, and consequently converge causing downward winds; (vi) compressional heating also occurs in the afternoon, in a region where expansion of the gas, and hence cooling, occurs during quiet geomagnetic times.

A Preliminary Investigation of the Empirical Validity of Study Quality Appraisal

2016 ◽  
Vol 50 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Bryan G. Cook ◽  
Danielle N. Dupuis ◽  
Asha K. Jitendra
Keyword(s):  
Special Education ◽  
Preliminary Investigation ◽  
Experimental Studies ◽  
Evidence Base ◽  
Study Quality ◽  
Students With Learning Disabilities ◽  
Quality Appraisal ◽  
High Quality ◽  
Evidence Based Practices

When classifying the evidence base of practices, special education scholars typically appraise study quality to identify and exclude from consideration in their reviews unacceptable-quality studies that are likely biased and might bias review findings if included. However, study quality appraisals used in the process of identifying evidence-based practices for students with learning and other disabilities have not been empirically validated (e.g., studies classified as unacceptable quality shown to have different, and presumably more biased, effects than high-quality studies). Using Gersten et al.’s (2005) approach for appraising the quality of group experimental studies in special education, we examined whether (a) studies classified as unacceptable quality and high quality had meaningfully different effects and (b) unacceptable-quality studies were more likely to have outlying effects than high-quality studies among 36 group experimental studies that investigated the effectiveness of instructional practices for students with learning disabilities. Our preliminary analyses found that the effects of unacceptable-quality studies were not meaningfully different from the effects of high-quality studies. We discuss implications of these findings and call for more research to be conducted in this area.

scholarly journals Effect of Aromatic System Expansion on Crystal Structures of 1,2,5-Thia- and 1,2,5-Selenadiazoles and Their Quaternary Salts: Synthesis, Structure, and Spectroscopic Properties

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4908
Author(s):  
Jan Alfuth ◽  
Beata Zadykowicz ◽  
Artur Sikorski ◽  
Tadeusz Połoński ◽  
Katarzyna Eichstaedt ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Building Blocks ◽  
Spectroscopic Properties ◽  
X Ray Diffraction ◽  
Aromatic System ◽  
Supramolecular Synthon ◽  
Quaternary Salts ◽  
Vis Spectroscopy ◽  
Td Dft ◽  
Secondary Bonding

Rational manipulation of secondary bonding interactions is a crucial factor in the construction of new chalcogenadiazole-based materials. This article reports detailed experimental studies on phenanthro[9,10-c][1,2,5]chalcogenadiazolium and 2,1,3-benzochalcogenadiazolium salts and their precursors. The compounds were synthesized, characterized employing NMR and UV-Vis spectroscopy. TD-DFT calculations were also performed. The influence of the size of the aromatic system on the molecular motifs formed by the compounds in the solid state has been studied by means of single-crystal X-ray diffraction. In case of the salts, the nature of an anion was also taken into consideration. The results show that cyclic [E···N]2 supramolecular synthon connects neighboring molecules of phenanthro[9,10-c][1,2,5]chalcogenadiazoles, with a relatively large aromatic system, in dimers regardless of the chalcogen atom in the molecule. Both N-methyl-2,1,3-benzothiadiazolium and N-methylphenanthro[9,10-c][1,2,5]chalcogenadiazolium cations have a strong affinity for triflate and iodide anions, therefore the formation of S···N or Se···N secondary bonding interactions is observed only in two out of the eight quaternary salts. Less coordinating anions must be used to enable the building blocks studied to form cyclic [E···N]2 synthons. Moreover, for two of the triflate salts, which are isostructural, a new supramolecular motif has been observed.

Growth and development in the pig, with special reference to carcass quality characters. I

1940 ◽  
Vol 30 (2) ◽  
pp. 276-343 ◽  
Author(s):  
C. P. McMeekan
Keyword(s):  
Growth And Development ◽  
Preliminary Investigation ◽  
Experimental Studies ◽  
The Body ◽  
Body Proportions ◽  
Differential Growth ◽  
Body Tissues ◽  
General Order ◽  
The Individual ◽  
Anterior Posterior

1. With the object of establishing the general order of development during post-natal life of the body proportions, tissues, and anatomical units, the relative changes with age in these characters have been studied in a series of male pigs killed at monthly intervals from birth to 7 months. The study is to be regarded in the light of a preliminary investigation, providing a background to experimental studies on the influence of nutrition on the growth and development of the pig.2. Growth in body proportions, when measured both photographically and by the weight of the individual anatomical regions, conforms to the law of developmental direction, exhibiting a well-defined anterior-posterior gradient from earlier to later developing regions. The limbs appear as relatively early developing parts with the fore limbs slightly earlier developing than the hind.3. The major body tissues exhibit marked differential growth behaviour; skeleton, muscle, and fat develop in that order. This situation has its origin in the differential rates of growth of the three tissues, in consequence of which the earlier developing skeleton makes a greater proportion of its growth earlier in life than does muscle, while the latter makes a greater proportion of its growth earlier than does the still later developing fat.4. Within any one tissue, the individual anatomical units or regions of the body similarly show well-defined differential growth relationships. Thus, the skeletal units of the head and trunk exhibit an anterior-posterior gradient in their order of development, while the bones of each limb show a centripetal gradient, the upper units being later developing than the lower units. To an even more marked degree, both the muscle and the fat surrounding these skeletal units afford evidence of similar gradients in these tissues.

Sign in / Sign up

Export Citation Format

Share Document