bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Hypodynamy on Structure and Alkaline Phosphatase Activity of Kidney in Japanese Quails
Authors: Almášiová V. , Cigánková V. , Holovská K. , Lenhardt Ľ. , Škrobánek P. , Massányi P. , Zibrín M.
Published: October 2008

The objective of the study was to observe the effect of experimental hypodynamy simulating weightlessness in space on the structure, ultrastructure and alkaline phosphatase activity of kidney in Japanese quail (Coturnix coturnix japonica). Two days after hatching, the quails were suspended in special shirts below the cage ceiling so their feet did not touch the floor. They could consume food and water ad libitum. Experimental animals were sacrificed after 14, 21, 28, 35, 42, 49 and 56 days of hypodynamy. Birds of the same age, hatched at the same time, and fed the same diet were used as a control. Samples of kidney were processed for light (LM) and transmission electron microscopy (TEM), and alkaline phosphatase (AP) analysis. Short-term (14–28 days) hypodynamy caused no marked damage to the structure and ultrastructure of kidneys. However, after long-term (35–59 days) hypodynamy, morphological changes were observed in some cells of the proximal and distal tubules. The dying cells in proximal tubules, observed in semi-thin sections by LM, were dark and contained a nucleus of irregular shape. Observation by TEM showed that their nucleus was dark and shrivelled and the electron-dense cytoplasm contained long, dense, rod-shaped mitochondria with thin mitochondrial cristae. Microvilli were present on the apical surface of cells and formed a brush border. Sporadic dying cells were also observed in distal tubules. Large, light vacuoles were found in the cytoplasm of cells of collecting tubules, however, the structure of renal corpuscles and medullary loops remained undisturbed. Microscopical analysis by means of a direct TUNEL reaction on days 35 to 59 of hypodynamy showed a moderate occurrence of cellular apoptosis in the proximal and distal tubules of experimental Japanese quail. The activity of AP in the brush border of the proximal tubules on days 14–29 of hypodynamy was normal in experimental animals and showed no significant differences in comparison with the control. Between days 35 and 59 of hypodynamy a moderate decrease in the content of AP in experimental animals in comparison with the control (P < 0.01) was observed. Our results indicated that long-term hypodynamy caused apoptosis of some cells in the proximal and distal tubules and therefore had a negative effect on the kidney structure. The occurrence of apoptosis was only sporadic. We presume no negative effect on the kidney function and the Japanese quails are capable of further development under the conditions of prolonged simulated weightlessness.
Blocking Both E-Selectin and P-Selectin Inhibits Neutrophil Recruitment into the Murine Testis after Ischemia-Reperfusion-Induced Injury
Authors: Celebi M. , Paul A. G. A.
Published: October 2008

Ischemia-reperfusion (IR) injury of the testis results in germ cell specific apoptosis, a process in which neutrophil recruitment to the testes plays a critical role. Adhesion molecules, in particular E- and P-selectins, play a critical role in this recruitment. The present study sought to characterize the inhibitory effect of function-blocking monoclonal anti-mouse E- and P-selectin antibodies on the migration of neutrophils into the IR-induced testis of the mouse. Mice were subjected to a 2 hr period of testicular torsion (ischemia) followed by detorsion (reperfusion). Ten minutes after the onset of reperfusion mice received either a mixture of 200 μg function-blocking monoclonal E-selectin and P-selectin antibody (FBMAb group; 100 μg; each) intravenously or 200 μg of isotype-matched control-antibody (IMCAb group). Separate groups of mice underwent shamoperation (SO group) or received 500 ng of TNFα (IF group) to induce inflammation. Mice were sacrificed 24 h after reperfusion and testicular interstitial cells were isolated and analyzed for the presence of neutrophils by means of flow cytometry. The mixture of function-blocking monoclonal E- and P-selectin antibody (FBMAb) decreased neutrophil recruitment to the IR-induced testis significantly (FBMAb group as compared to the IMCAb group 20.2 ± 2.8 vs. 51.9 ± 4.0 % Gr-1+CD11b+ of total leukocytes; p = 0.0002). Therefore, blocking both E- and P-selectin may be therapeutically beneficial to protect postischemic testis.
Analytical Control of a Starter Pig Feed Medicated with Amoxicillin
Authors: Zemanová M. , Maxa J. , Hera A. , Haas Z. , Lemaire F. , Sanquer A. , Bousquet E.
Published: October 2008

Amoxicillin concentrations were determined by two independent laboratories for a pig starter feed medicated from a coated amoxicillin premix. The analytical method was previously transferred from one laboratory to the other one. The data between the two laboratories were consistent, showing ruggedness of the assay. Mean amoxicillin feed concentrations before and after pelletization were higher than 90% of the theoretical content, confirming satisfactory stability of this active ingredient in the coated form tested.
Oral Hypoglycaemic Drugs in Alloxan-Induced Diabetes Mellitus in Dogs
Authors: Balogh É. , Tóth M. , Bölcsházi G. , Abonyi-Tóth Zs. , Kocsis E. , Semjén G.
Published: October 2008

The effect of the alpha-glycosidase inhibitor acarbose, the insulin sensitiser metformin and the insulin secretiser gliclazide on blood glucose level of dogs were examined in experimental diabetes. Dogs were randomly divided into three groups. During the first week of the experimental period control blood glucose data were determined. During the subsequent five weeks, the first group (n = 6) was administered acarbose (200 mg/dog/day), the second (n = 5) was treated with metformin (1700 mg/dog/day), and the third was given gliclazide (160 mg/dog/day). The drug was administered twice daily when feeding at 7:00 and 15:00 h. The average difference between postprandial and fasting blood glucose was determined for the treated and the control period, and the statistical significance of their difference (mean decrease) was evaluated by two-sampled t-test. The mean decrease in blood glucose was 0.49 mmol/l (P = 0.09) for acarbose, 1.15 mmol/l (P = 0.01) for metformin, and 0.08 mmol/l (P = 0.88) for gliclazide. According to the results of statistical evaluation, metformin was the only drug that caused a significant decrease in postprandial blood glucose.
Local and Systemic Up-regulation of TNFα, IL-1β and IL-6 in Mice Intratracheally Inoculated with Porphyromonas gingivalis
Authors: Pavlica Z. , Nemec A. , Nemec-Svete A. , Eržen D. , Crossley D. A. , Petelin M.
Published: October 2008

The objective of the study was to find whether a single intratracheal inoculation with live Porphyromonas gingivalis ATCC 33277 influences local and systemic inflammatory and immune responses in mice.Twelve-week-old BALB/c mice were intratracheally inoculated with 2.9 × 109 CFU P. gingivalis ATCC 33277 diluted in 40 μl sterile phosphate buffer (treated group) or with sterile PBS (control group). The animals were sacrificed 2, 6, 24, 72 and 168 h after inoculation. TNFα, IL-1β, IL-6 and total protein concentrations were measured in the serum, lungs and kidneys. Six hours after P. gingivalis inoculation, TNFα concentration was significantly increased in serum (p = 0.02) and kidneys (p = 0.04), but in the lungs TNFα production was enhanced already 2 h (p < 0.0001) after inoculation, reaching the peak after 6 h (p < 0.0001). The IL-1β concentration was also significantly increased in serum after 2 h (p = 0.006), remaining significantly elevated up to 3 days (p ≤ 0.0001) after inoculation. In lungs IL-1β levels were significantly increased 6 and 24 h (p < 0.0001) and in kidneys 24 h (p < 0.0001) and 168 h (p = 0.01) after inoculation. The IL-6 concentration was significantly increased in serum after 72 and 168 h (p < 0.0001). However, IL-6 was significantly increased in lungs after 6 h (p < 0.0001), remaining elevated until 72 h and in kidneys 2 and 6 h (p < 0.0001) after inoculation. Significantly increased total protein concentration was detected in kidneys 6 and 24 h (p < 0.0001) after inoculation. These results suggest that a single intratracheal inoculation with P. gingivalis stimulates the local and systemic inflammatory and immune response, as shown by increased tissue and serum levels of proinflammatory cytokines.
Indirect Enzyme Linked Immunosorbent Assay for Diagnosis of Brucellosis in Buffaloes
Authors: Munir R. , Rehman S. T. Ur , Kausar R. , Naqvi S. M. Saqlan , Farooq U.
Published: October 2008

Brucellosis is an important zoonotic disease causing significant economic losses worldwide. Early detection of this disease is essential for its control and eradication. Presently, an Indirect Enzyme Linked Immunosorbent Assay (I-ELISA) was developed using lipopolysaccharide (LPS) as antigen and compared with the commercial kit using one hundred negative and positive sera each from buffaloes. The agreement for the positive result between the developed and commercial I-ELISA was 78% and for the negative it was 100%. At 52.49%, 53.09%, 53.26%, 53.86% and 53.94% cut off the sensitivity was 100%, 100%, 97.53%, 88.93% and 86.42%, while the specificity was 84.03%, 84.87%, 85.71%, 87.39% and 87.39%, respectively, for developed I-ELISA. This developed test can be used for the screening of herds as the relative sensitivity is higher.
Effects of Eugenol and MS-222 Anaesthesia on Siberian Sturgeon Acipenser baerii Brandt
Authors: Gomulka P. , Własow T. , Velíšek J. , Svobodová Z. , Chmielinska E.
Published: October 2008

The aim of the present study was to assess changes induced in the organism of Siberian sturgeon (Acipenser baerii) by eugenol and MS-222 anaesthesia on the basis of haematological indices, biochemical blood profile values and histological examinations. The haematological and biochemical indices were assessed in fish immediately and 24 h after anaesthesia. The results showed that despite no mortality occurred after anaesthesia in both 125 mg l-1 of MS-222 and 0.075 ml l-1 of eugenol, these chemical substances severely influenced the constituents of Siberian sturgeon blood and resulted in some histological changes in the gills and liver. Both eugenol and MS-222 anaesthesia caused erythrocyte swelling and haemolysis. The severe depletion of leukocyte number occurred 24 h after both eugenol and MS-222 anaesthesia (mainly due to depletion of lymphocyte, neutrophil segments and eosinophil fractions). Total protein, total globulin, triacylglycerol concentration and alanine aminotransferase activity in blood plasma was significantly elevated (p < 0.01) after both eugenol and MS-222 anaesthesia. The concentration of Ca2+, inorganic phosphate, NH3 and alkaline phosphatase activity were significantly decreased (p < 0.01) compared to control. No significant changes were noticed in the albumin and glucose concentrations and the activity of lactate dehydrogenase, aspartate aminotrasferase and creatinkinase. Results of the examinations suggest that the use of MS-222 (125 mg l-1) and eugenol (0.075 ml l-1) does not cause irreversible damage in Siberian sturgeon.
Schooling and the Encouragement of Farming Amongst Pastoralists in Tanzania
Authors: Bishop Elizabeth
Published: October 2008

This article uses qualitative and quantitative data to document the nature of educational practices in a pastoralist area in Tanzania, and to provide evidence that the schooling process, amongst other influences, has encouraged and facilitated the uptake and expansion of farming by these pastoralists. The article argues that the schooling process has influenced pastoralists' livelihood choices, and thus the nature and viability of pastoralism.
Quantitative Analyse der Verwaldung von Felsflühen im Nordwestschweizer Jura | Quantitative analysis of overgrowing forest around cliffs in the northwestern Swiss Jura mountains
Authors: Müller Stefan W. , Rusterholz Hans-Peter , Zieschang Olaf , Ginzler Christian , Baur Bruno
Published: October 2008

The limestone cliffs of the Jura mountains in northwestern Switzerland harbour a diverse flora with several relic populations of arctic-alpine and Mediterranean plant species. Overgrowing forests increasingly threaten rare, relic plant species with high light demands on cliffs, because traditional forms of forest use, including the collection of firewood and grazing by goats, were abandoned. We examined the temporal and spatial patterns of overgrowing forest at six cliffs in the northwestern Swiss Jura mountains by analysing tree cover on time-series air photographs made between 1951 and 2000. Overall tree cover increased from 60% to 85% at the six cliffs examined between 1951 and 1964 and then levelled off. The increase in tree cover showed distinct spatial patterns. The cover increased significantly in the talus and on the cliff face, but not on the plateau (at the top of the cliffs). Our results confirm the assumption that the cliff forests became denser during the last decades. Forestry practices such as selective thinning or controlled grazing by goats are suggested as a method of promoting the threatened relic plant species.
Structural And Energetic Changes of Si (100) Surface With Fluorine in Presence of Water – A Density Functional Study
Authors: Chatterjee Abhijit , Iwasaki Takashi , Ebina Takeo
Published: October 2008

We report density functional electronic structure calculations to monitor the change in the surface characteristics of the Si (100)-2x1 surface after fluorination followed by interaction with water. Embedded finite silicon clusters are used to model an extended Si (100)-2x1 surface. Two high symmetry pathways and subsequent adsorption sites were examined: (i) adsorption of an fluorine atom directing onto a silicon dangling bond to form a monocoordinated fluorine atom (ii) adsorption of a fluorine atom directing on top of silicon dimer to form a bridging dicoordinated fluorine atom. However, in the later case we find that no barrier exists for the bridging fluorine atom to slide towards silicon dimer dangling bond to form more stable mono coordinated Si-F bond. We calculated activation barriers and equilibrium surface configuration as a function of fluorine coverage upto 2.0 ML. We compared the stability of the fluorinated surface. The results were compared with existing experimental and theoretical results. The reaction of water with HF treated Si surface is monitored. It produces, as a first step, the exchange of Si-F with water to form Si-OH groups reducing the concentration of the fluorine on the surface, followed by a rapture of Si-Si bonds and finally the Si-O-Si bridge formation in the lattice.
Extended Coupled Cluster Approach for Molecular Properties: Study of H2O and HF Complexes
Authors: Vaval Nayana , Kumar Aparna  Basu , Pal Sourav
Published: October 2008

In this paper, we study stationary variant of extended coupled-cluster response approach for properties. This has been studied at the singles and doubles approximation using cubic-truncated functional. This approximation has been studied earlier around equilibrium for small molecules. In this paper, efficacy of this approximation has been shown using perturbative arguments. Further we have calculated dipole moments and polarizabilities of weakly interacting dimers of HF, H2O and H2O - HF complex. Results of HF and H2O monomers have been presented at the same level for comparison. The results have been compared with experimental results, wherever available and other theoretical results.
Maximum Topological Distances Based Indices as Molecular Descriptors for QSPR. 4. Modeling the Enthalpy of Formation of Hydrocarbons from Elements
Authors: Mercader Andrés , Castro Eduardo  A. , Toropov Andrey  A.
Published: October 2008

The enthalpy of formation of a set of 60 hydroarbons is calculated on the basis of topological descriptors defined from the distance and detour matrices within the realm of the QSAR/QSPR theory. Linear and non-linear polynomials fittings are made and results show the need to resort to higher-order regression equations in order to get better concordances between theoretical results and experimental available data. Besides, topological indices computed from maximum order distances seems to yield rather satisfactory predictions of heats of formation for hydrocarbons.
Quantum Chemical Studies on Molecular and Electronic Structure of Platinum and Tin Adducts with Guanine
Authors: Chojnacki Henryk , Kolodziejczyk Wojciech , Pruchnik Florian
Published: October 2008

The electronic structure of model platinum-guanine and tin-guanine adducts has been studied both at semiempirical level and by using ab initio methods at the correlation level. The possible binding energies have been evaluated and most probable strustures were determined. In all cases the binding enegies of the gaseous tin chelates are rather large. The stabilizing role of the hydrogen bonds has been pointed out in tinguanine chelates as well as comparison with the relevant platinum complexes is discussed.
The Adsorption of Nitromethane on the Au (111) Surface
Authors: Gomes J.  R. B. , Illas F.
Published: October 2008

The density functional theory (DFT) based hybrid-method B3LYP has been used to study the interaction of the nitromethane molecule (CH3NO2) with the Au(111) surface. The perfect Au(111) surface has been represented by a rather large cluster model, Au22, that was in turn used to extract information about the preferred adsorption geometry of the CH3NO2 species. In order to extract energetic information about the stability of adsorbed nitromethane, calculations were also performed for the gas-phase CH3NO2 molecule. The results obtained here are used to interpret experimental data. The computed geometry for adsorbed CH3NO2 agrees with the structure proposed from a previous experimental work.
The CuCl2/Al2O3 Catalyst Investigated in Interaction with Reagents
Authors: Lamberti Carlo , Prestipino Carmelo , Capello Luciana , Bordiga Silvia , Zecchina Adriano , Spoto Giuseppe , Moreno Sofia  Diaz , Marsella Andrea , Cremaschi Barbara , Garilli Marco , Vidotto Sandro , Leofanti Giuseppe
Published: October 2008

Alumina supported CuCl2, the basic catalyst for ethylene oxychlorination, has been investigated by UV-Vis spectroscopy, EPR, EXAFS and XANES in a wide range (0.25-9.0 wt%) of Cu concentration. We have evidenced that, at low Cu content, the formation of a surface aluminate species takes place. The formation of this surface copper aluminate stops at 0.95 wt% Cu / 100 m2; at higher Cu concentrations excess copper chloride precipitates directly from solution during the drying step forming an highly dispersed CuCl2.H2O, phase, overlapping progressively the surface aluminate. Depletion tests and IR spectroscopy of adsorbed NO have demonstrated that the latter is the only active phase. A complete catalytic cycle has then been performed on CuCl2/Al2O3 catalyst. EPR, XANES and EXAFS, have been used to demonstrate that the ethylene oxychlorination reaction: C2H4 + 2HCl + ½ O2 --> C2H4Cl2 + H2O follows a three steps mechanism: (i) reduction of CuCl2 to CuCl (2CuCl2 + C2H4 --> C2H4Cl2 + 2CuCl), (ii) oxidation of CuCl to give an oxychloride (2CuCl + ½ O2 --> Cu2OCl2) and (iii) closure of the catalytic circle by rechlorination with HCl, restoring the original CuCl2 (Cu2OCl2 + 2HCl --> 2CuCl2 + H2O). Finally, we have shown that time resolved, in situ, spectroscopy is a very promising technique to investigate the interplay between catalyst activity and oxidation state of copper.
CO Adsorption on Co(0001)-Supported Pt Overlayers
Authors: Légaré P. , Madani B. , Cabeza G. F. , Castellani N. J.
Published: October 2008

The growth of Pt deposits on Co(0001) was followed by STM and XPS. The chemical reactivity of the resulting surface was checked by CO adsorption. Pt grows as dendritic islands on the Co terraces whereas forming stripes at the Co step edges. Annealing the sample has no apparent effect on the STM pictures. However, XPS suggests that a limited dilution of Pt in Co takes place. The adsorption of CO on the surface is drastically affected by the presence of Pt even for minute traces. The adsorption energy on the Pt areas is decreased by 40 %. The maximum coverage on the Co areas is also decreased. This indicates that Pt impurities diluted in Co have a high passivating power as a consequence of the induced electronic changes.
In Our Own Image: Personal Symmetry in Discovery
Authors: Lin Shu-Kun
Published: October 2008

I gave lectures entitled "Ugly Symmetry" at several conferences and many institutes during past six years.[...]
Structural transitions in biomolecules - a numerical comparison of two approaches for the study of phase transitions in small systems
Authors: Alves Nelson , Hansmann Ulrich , Peng Yong
Published: October 2008

We compare two recently proposed methods for the characterization of phase transitions in small systems. The usefulness of these techniques is evaluated for the case of structural transition in alanine-based peptides.
From Metal Cluster to Metal Nanowire: A Topological Analysis of Electron Density and Band Structure Calculation
Authors: Li Feng-Yin , Chen Likey , Mou Chung-Yuan , Peng Shie-Ming , Wang Yu
Published: October 2008

We investigate a theoretical model of molecular metalwire constructed from linear polynuclear metal complexes. In particular we study the linear Crn metal complex and Cr molecular metalwire. The electron density distributions of the model nanowire and the linear Crn metal complexes, with n = 3, 5, and 7, are calculated by employing CRYSTAL98 package with topological analysis. The preliminary results indicate that the bonding types between any two neighboring Cr are all the same, namely the polarized open-shell interaction. The pattern of electron density distribution in metal complexes resembles that of the model Cr nanowire as the number of metal ions increases. The conductivity of the model Cr nanowire is also tested by performing the band structure calculation.
Charge Exchange in Low-Energy H, D + C4+ Collisions with Full Account of Electron Translation
Authors: Belyaev A. K. , Grosser J. , Liévin J. , Vaeck N.
Published: October 2008

We report the application of the quantum approach, which takes full account of electron translation at low collisional energies, to the charge exchange process H, D + C4+ → H+, D+ + C3+(3s; 3p; 3d). The partial and the total integral cross sections of the process are calculated in the energy range from 1 till 60 eV/amu. It is shown that the present results are independent from the upper integration limit for numerical solution of the coupled channel equations although nonadiabatic couplings remain nonzero up to infinity. The calculated partial and total cross sections are in agreement with the previous low-energy calculations and the available experimental data. It is shown that for low collisional energies the isotopic effect takes place. The observed effect is explained in terms of the nonadiabatic dynamics.
Chemical Reactivity Dynamics and Quantum Chaos in Highly Excited Hydrogen Atoms in an External Field: A Quantum Potential Approach
Authors: Chattaraj P. K. , Maiti B.
Published: October 2008

Dynamical behavior of chemical reactivity indices like electronegativity, hardness, polarizability, electrophilicity and nucleophilicity indices is studied within a quantum fluid density functional framework for the interactions of a hydrogen atom in its ground electronic state (n = 1) and an excited electronic state (n = 20) with monochromatic and bichromatic laser pulses. Time dependent analogues of various electronic structure principles like the principles of electronegativity equalization, maximum hardness, minimum polarizability and maximum entropy have been found to be operative. Insights into the variation of intensities of the generated higher order harmonics on the color of the external laser field are obtained. The quantum signature of chaos in hydrogen atom has been studied using a quantum theory of motion and quantum fluid dynamics. A hydrogen atom in the electronic ground state (n = 1) and in an excited electronic state ( n = 20) behaves differently when placed in external oscillating monochromatic and bichromatic electric fields. Temporal evolutions of Shannon entropy, quantum Lyapunov exponent and Kolmogorov – Sinai entropy defined in terms of the distance between two initially close Bohmian trajectories for these two cases show marked differences. It appears that a larger uncertainty product and a smaller hardness value signal a chaotic behavior.
First Principles Molecular Dynamics Study of Catalysis for Polyolefins: the Ziegler-Natta Heterogeneous System.
Authors: Boero Mauro , Terakura Kiyoyuki , Parrinello Michele
Published: October 2008

We review part of our recent ab initio molecular dynamics study on the Ti-based Ziegler-Natta supported heterogeneous catalysis of α-olefins. The results for the insertion of ethylene in the metal-carbon bond are discussed as a fundamental textbook example of polymerization processes. Comparison with the few experimental data available has shown that simulation can reproduce activation barriers and the overall energetics of the reaction with sufficient accuracy. This puts these quantum dynamical simulations in a new perspective as a virtual laboratory where the microscopic picture of the catalysis, which represents an important issue that still escapes experimental probes, can be observed and understood. These results are then discussed in comparison with a V-based catalyst in order to figure out analogies and differences with respect to the industrially more successful Tibased systems.
Nature of Copper Active Sites in CuZSM-5: Theory and Experiment
Authors: Broclawik Ewa , Datka Jerzy , Gil Barbara , Kozyra Pawel
Published: October 2008

We report here a concise resume reporting the way of constructing the model of an active site composed of transition metal cation exchanged in zeolites. The main goal was to devise the model of CuZSM-5 capable of describing geometrical and electronic properties of metal sites and adsorption complexes with small molecules. The models were built up starting from simple ring structures encountered in ZSM-5 framework to fused rings’ model selected as the representative of α position for hosting the exchanged cation. Geometrical and electronic properties of the basal model, composed of the extended framework cluster with Cu+ or Cu2+ cation, and adsorption complexes with diatomic molecules were extracted from DFT calculations. The stress was put here on direct confirmation of structural changes on copper reduction/oxidation and adsorption. Electron donor/acceptor properties of the sites combined with electronic properties of adsorbed molecules led to the proposal for the mechanism of NO activation by Cu+ZSM-5: transfer of electrons from copper d orbitals to antibonding states of NO should cause large weakening of the bond, which was evidenced also by IR measurements.
Alternative Multi–reference State–specific Coupled Cluster Wave Functions
Authors: Adamowicz Ludwik , Malrieu Jean–Paul , Ivanov Vladimir V.
Published: October 2008

An analysis of alternative expressions of the state–specific (SS) multi–reference (MR) coupled cluster (CC) wave functions is presented. The approach utilizes the CASSCF (complete active space self consistent field) wave function as the reference. It is designed specifically for calculating excited electronic states. The cluster structure of the CC wave operator and the origin(s) for the cluster expansion(s) are the key features of the development. Test calculations reveal some interesting features of the SMRCC approaches.
To Multireference or not to Multireference: That is the Question?
Authors: Bartlett Rodney J.
Published: October 2008

I present a personal viewpoint on multi-reference coupled-cluster theory, its pros and cons. I also suggest some criteria that should be satisfied by multi-reference CC, not the least of which is to develop a tool that will be (almost!) as easy to apply as today’s powerful array of single reference coupled-cluster methods. Some approaches like the equation of motion CC method offers a multi-reference description of some target states, while being entirely single reference in execution. Perhaps it offers a model for further generalization to a wider array of multi-reference problems.
Multi-state Multireference Rayleigh–Schrödinger Perturbation Theory for Mixed Electronic States: Second and Third Order
Authors: Shavitt Isaiah
Published: October 2008

The formalism for multi-state multireference configuration-based Rayleigh-Schrödinger perturbation theory and procedures for its implementation for the second-order and third-order energy within a multireference configuration interaction computer program are reviewed. This formalism is designed for calculations on electronic states that involve strong mixing between different zero-order contributions, such as avoided crossings or mixed valence-Rydberg states. Such mixed states typically display very large differences in reference-configuration mixing coefficients between the reference MCSCF wave function and an accurate correlated wave function, differences that cannot be reflected in state-specific (diagonalize-then-perturb) multireference perturbation theory through third order. A procedure described in detail applies quasidegenerate perturbation theory based on a model space of a few state-averaged MCSCF functions for the states expected to participate strongly in the mixing, and can be characterized as a “diagonalize-then-perturb-thendiagonalize” approach. It is similar in various respects to several published methods, including an implementation by Finley, Malmqvist, Roos, and Serrano-Andrés [Chem. Phys. Lett. 1998, 288, 299–306].
Quantum Chemical and FTIR Spectroscopic Studies on the Linkage Isomerism of Carbon Monoxide in Alkali-Metal-Exchanged Zeolites: A Review of Current Research
Authors: Areán C.  Otero , Palomino G.  Turnes , Tsyganenko A.  A. , Garrone E.
Published: October 2008

When adsorbed (at a low temperature) on alkali-metal-exchanged zeolites, CO forms both M(CO)+ and M(OC)+ carbonyl species with the extra-framework alkali-metal cation of the zeolite. Both quantum chemical and experimental results show that C-bondend adducts are characterized by a C−O stretching IR band at a frequency higher than that of 2143 cm-1 for free CO, while for O-bonded adducts this IR band appears below 2143 cm-1. The cation-CO interaction energy is higher for M(CO)+ than for M(OC)+ carbonyls, although the corresponding difference decreases substantially when going from Li+ to Cs+. By means of variable-temperature FTIR spectroscopy, this energy difference was determined for several alkali-metal cations, and the existence of a thermal equilibrium between M(CO)+ and M(OC)+ species was established. The current state of research in this field is reviewed here, with a view to gain more insight into the thermal isomerization process.
A Protons Exchanged Montmorillonite Clay as an Efficient Catalyst for the Reaction of Isobutylene Polymerization
Authors: Harrane Amine , Meghabar Rachid , Belbachir Mohammed
Published: October 2008

“Maghnite” a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite” is an efficient catalyst for cationic polymerization of many vinylic and heterocyclic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001). The structure compositions of both “Maghnite” and “H-Maghnite” have been developed. Isobutylene monomer, wich is polymerizable only by cationic process (Odian,G. La Polymerisation :principes et Applications; Ed.Technica: New York, 1994; pp 222-226), was used to elucidate the cationic character of polymerization. The polymerization was performed under suitable conditions at isobutylene vaporization temperature (–7°C). Experiments revealed that polymerization induced by “H-Maghnite” proceed in bulk and in solution. In contrast to findings with methylene chloride CH2Cl2 as a polar solvent, polymerization yields with hexane C6H14 non-polar solvent is very significant. In bulk polymerization, Isobutylene conversion increases with increasing “H-Maghnite” proportion.
15N Chemical Shifts in Energetic Materials: CP/MAS and ab Initio Studies of Aminonitropyridines, Aminonitropyrimidines, and Their N-Oxides
Authors: Anderson Karen L. , Merwin Lawrence H. , Wilson William S. , Facelli Julio C.
Published: October 2008

Solid state 15N NMR chemical shift measurements have been performed on a series of nitro- and amino-substituted nitrogen-containing heterocycles that are of interest as potential new insensitive explosives. Due to low solubilities, many of these compounds are not amenable to study by solution state methods. Theoretical calculations of 15N chemical shift parameters have been performed on the structures of interest and are reported herein. The calculated and experimental values are in good agreement. The use of a model that includes intermolecular effects and allows the proton positions of the nearest neighbors to be optimized leads to the best agreement between calculated and experimental values. The theoretical models accurately predict the effects of nitro and amino substituents on ringnitrogen chemical shifts, explaining a seeming reversal in trend that is noted in the pyridine and pyridine-1-oxide chemical shifts of the highly substituted compounds.
Ab Initio Calculations of 31P NMR Chemical Shielding Anisotropy Tensors in Phosphates: Variations Due to Ring Formation
Authors: Alam Todd M.
Published: October 2008

Ring formation in phosphate systems is expected to influence both the magnitude and orientation of the phosphorus (31P) nuclear magnetic resonance (NMR) chemical shielding anisotropy (CSA) tensor. Ab initio calculations of the 31P CSA tensor in both cyclic and acyclic phosphate clusters were performed as a function of the number of phosphate tetrahedral in the system. The calculation of the 31P CSA tensors employed the GAUSSIAN 98 implementation of the gauge-including atomic orbital (GIAO) method at the Hartree-Fock (HF) level. It is shown that both the 31P CSA tensor anisotropy, and the isotropic chemical shielding can be used for the identification of cyclic phosphates. The differences between the 31P CSA tensor in acyclic and cyclic phosphate systems become less pronounced with increasing number of phosphate groups within the ring. The orientation of the principal components for the 31P CSA tensor shows some variation due to cyclization, most notably with the smaller, highly strained ring systems.
A Message from the Director
Authors: McNairy Sidney
Published: October 2008

The National Institutes of Health (NIH), located in Bethesda, Maryland, a suburb of Washington, D.C., is one of the agencies of the Public Health Services that, in turn, is part of the U.S. Department of Health and Human Services.[...]
Transcriptional Activation of Stress Genes and Cytotoxicity in Human Liver Carcinoma (HepG2) Cells Exposed to Pentachlorophenol
Authors: Dorsey Waneene C. , Tchounwou Paul B. , Ishaque Ali B. , Shen Elaine
Published: October 2008

Pentachlorophenol (PCP) is a biocidal chemical with several industrial, agricultural, and domestic applications. There is accumulating evidence indicating that PCP is highly toxic to humans, with major target organs including the lung, liver, kidneys, heart, and brain. Little is known regarding the molecular basis by which PCP induces toxicity, mutagenesis, and carcinogenesis. Therefore, this research was designed to assess the cellular and molecular responses of HepG2 cells following exposure to PCP. The cytotoxicity experiment yielded a LD50 value of 23.4 + 9.7 μg PCP/mL upon 48 hrs of exposure, indicating that PCP is acutely toxic. A dose-response relationship was recorded with respect to gene induction. For example, fold inductions of CYP1A1 were 1.0 + 0.0, 1.0 + 0.0, 1.3 + 0.5, 6.3 + 4.3, and 22.5 + 3.5 for 0, 6.2, 12.5, 25, and 50 μg PCP/mL, respectively. Overall, five out of the thirteen recombinant cell lines tested showed inductions to statistically significant levels (p < 0.05). At 50 μg PCP/mL, the average fold inductions were 22.5 + 3.5, 52.8 + 2.5, 8.4 + 1.9, 6.16 + 2.4, and 12.5 + 6.8, for CYP1A1, XRE, HMTIIA, c-fos, and GADD153, respectively. These results indicate the potential of PCP to undergo Phase I biotransformation in the liver (CYP1A1, XRE), to cause cell proliferation (c-fos), growth arrest and DNA damage (GADD153), and to influence the toxicokinetics of metal ions (HMTIIA). Marginal inductions were recorded for HSP70, CRE, RARE, GADD45, and GRP78. Within the dose range (0-100 μg/mL) tested, no significant inductions (p < 0.05) were observed for GSTYa, NFkBRE, and p53RE.
Pilot Study: A Non-Invasive Urine Test for Potential Prostate Abnormalities
Authors: Cohly H. H. P. , Koelle M. S. , Angel M. F. , Das S. K. , Shingleton W. B.
Published: October 2008

Currently, serum is used more often than urine to detect prostate specific antigen (PSA). The need for a non-invasive test yielding similar results led us to develop a urine test that uses solar irradiated water as a reactant species. To develop this technology, seven reagents plus one control were produced by exposure of water for 40 days in sunlight to the colors of the visible spectrum through colored cellophane, control being an unwrapped bottle of sterile water. Patients (127) were examined for serum PSA and the urine was tested using the above reagents. A positive urine test was observed with yellow-filtered irradiated water which absorbed at 454nm. Twenty-five of the 45 patients with positive results for the urine test had PSA levels of 0.21-4.0 ng/ml. Thus, this pilot study describes a non-invasive urine test mainly positive in patients with PSA 0.21-4.0 ng/ml.
Functionally-Impaired HIV-1 Nef Alleles from a Mother-Child Transmission Pair
Authors: Roth William W. , Khan Mafhuz , Geleziunas Romas , Stringer Harold G. , Zuberi Jalal A. , Greene Warner C. , Powell Michael , Bond Vincent C.
Published: October 2008

Unusual HIV-1 nef alleles were isolated from a woman and her vertically infected child. Both patients eventually progressed to develop AIDS. The child died at age 6.5 years, while the mother is currently alive, 13 years since her diagnosis with HIV-1. Predicted amino acid sequences of both mother and child Nefs diverged from the HIV-1 clade B consensus. In particular, they exhibited two separate 5-amino acid deletions bracketing a Cterminal dileucine regulatory motif and Trp-Gly mutations at the site for cleavage by the HIV-1 protease. The child’s Nef showed a modest ability to enhance HIV-1 infectivity in MAGI cells, whereas the mother’s Nef did not alter HIV-1 infectivity in the assay. Both Nefs were partially functional for CD4 down-regulation. The child’s Nef was fully functional for MHC-1 down-regulation, while the maternal Nef was non-functional. To our knowledge this study is the first to describe a functional divergence between Nef alleles in a case of mother-to-child HIV-1 transmission.
Neurotoxic Activity of the HIV-1 Envelope Glycoprotein: Activation of Protein Kinase C in Rat Astrocytes
Authors: Adeyemo Oyewole , Wu Rong , Parker Scott , Benveniste Etty N. , Hunter Eric , Adebayo Isaac
Published: October 2008

Envelope glycoprotein (gp120) of the human immunodeficiency virus type one (HIV-1), has adverse effects on glial cells and neurons. This study reports on the direct effect of recombinant gp120 (r-gp120) produced from different expression systems on protein kinase C, as a measure of relative neurotoxicity. Brain cells were grown in vitro from explants of the cerebral cortex of newborn rats, and recombinant gp120 preparations expressed in mammalian cell/vaccinia virus and insect cell/baculovirus systems were applied to astrocyte-enriched cultures. The gp120 preparations activated protein kinase C (PKC) to similar levels in these cells. Mutant recombinant gp120 lacking the amino-terminal 29 amino acids produced from the mammalian and insect cells also activated PKC to similar levels as did the full-length protein. The recombinant proteins specifically activated PKC β and ζ, suggesting that they are able to induce both Ca2+-dependent and Ca2+-independent isoforms of this enzyme. Alteration of PKC activity in astrocytes by gp120 indicates its ability to modulate gene expression, which is associated with the neurotoxicity of this protein. Furthermore, the results suggest that the deletion of the first 29 residues of NH2-terminal end of the gp120 does not affect the functional activity of this protein with regard to modulation of signal transduction in astrocytes.
Influence of Humic Acid on 1-Aminopyrene Ecotoxicity During Solar Photolysis Process
Authors: Balarezo Ana L. , Jones Veleka N. , Yu Hongtao , Hwang Huey-Min
Published: October 2008

1-Aminopyrene (1-AP), a polycyclic aromatic hydrocarbons (PAH) compound, is a major metabolite during biotransformation of 1-nitropyrene by microflora in natural environment and in the guts of animals and humans. Under UV-A irradiation, 1-AP has been shown to cause light-induced DNA single strand cleavage. Humic acids (HA) in aquatic ecosystems can influence the bioavailability, toxicity, and fate of organic xenobiotics. Therefore, photochemical fate and effect of PAH in natural aquatic environment may differ significantly across sites. The objectives of this study are to assess the time course (TC; 18 and 90 minutes) influence of HA (0, 20, and 60 ppm) on microbial ecotoxicity of 1-AP (0 and 10 μM) during solar photolysis process (PP). Microbial ecotoxicity of 1-AP during different time courses in the presence and absence of HA was measured with spread plate counting and microbial mineralization of 14C-D-glucose. The experimental results were analyzed as factorial arrangements of treatment in a complete randomized design using General Linear Model by SAS. LSMEANS was used to separate means or combination of means. Significant effect on glucose mineralization was found by the following treatment interactions 1-AP*TC, 1-AP*PP, TC*PP, HA*1-AP*TC, HA*1-AP*PP, and HA*1-AP*TC*PP. The treatment interaction HA*1-AP was the only one affecting spread plate counting. In the groups exposed to 1-AP (10 μM), microbial heterotrophic mineralization of 14C-D-glucose was significantly inhibited in the presence of HA in light and in darkness. Exposure to HA in light and darkness, however, did not necessarily inhibit bacterial viability at the HA concentration range assayed. Therefore, inhibition on microbial activity could have been caused by multiple factors, instead of toxicity of HA alone.
Interaction Energy Analysis of Nonclassical Antifolates with Pneumocystis carinii Dihydrofolate Reductase
Authors: Pitts Conrad , Yin Jian , Bowen Donnell , Maxwell Celia J. , Southerland William M.
Published: October 2008

The x-ray structure of the Pneumocystis carinii dihydrofolate reductase (DHFR):trimethoprim:NADPH ternary complex obtained from the Protein Databank was used as a structural template to generate models for the following complexes: P. carinii DHFR:piritrexim:NADPH, P. carinii DHFR:epiroprim:NADPH, and P. carinii DHFR:trimetrexate:NADPH. Each of these complexes, including the original trimethoprim complex was then modeled in 60 angstrom cubes of explicit water and minimized to a rms gradient between 1.0 to 3.0 x 10-5 kcal/angstrom. Subsequently, each antifolate structure was subdivided into distinct substructural regions. The minimized complexes were used to calculate interaction energies for each intact antifolate and its corresponding substructural regions with the P. carinii DHFR binding site residues, the DHFR protein, the solvated complex ( which consists of P. carinii DHFR, NADPH, and solvent water), solvent water alone, and NADPH. Antifolate substructural regions which contained nitrogen and carbon atoms in an aromatic environment (i. e. the pteridyl, pyridopyrimidinyl, and diaminopyrimidinyl subregions) contributed most to the stability of antifolate interactions, while interaction energies for the hydrocarbon aromatic rings, methoxy, and ethoxy groups were much less stable. Additionally, interaction energy analyses were calculated for carbon and nitrogen atoms of the pteridyl, pyridopyrimidinyl, and diaminopyrimidinyl subregions and for the carbon and oxygen atoms of methoxy and ethoxy subregions. The contributions of hydrogen atoms were included with those of the carbon, nitrogen and oxygen atoms to which they are attached. These analyses revealed that the carbon atoms of the pteridyl, pyridopyrimidinyl, and diaminopyrimidinyl subregions generally contributed most to the stability of those regions. Carbon atoms also contributed favorably to the stability of the methoxy group interactions. Those substructural regions which exhibit relatively unfavorable interaction energies may constitute important modification targets in the design of improved P. carinii DHFR inhibitors. Interaction energies for different groups of atoms within the substructural regions suggest strategies for modification of the substructural regions.
Cytotoxicity and Proliferation Studies with Arsenic in Established Human Cell Lines: Keratinocytes, Melanocytes, Dendritic Cells, Dermal Fibroblasts, Microvascular Endothelial Cells, Monocytes and T-Cells
Authors: Graham-Evans Barbara , Tchounwou Paul , Cohly Hari
Published: October 2008

Based on the hypothesis that arsenic exposure results in toxicity and mitogenecity, this study examined the dose-response of arsenic in established human cell lines of keratinocytes (HaCaT), melanocytes (1675), dendritic cells (THP-1/A23187), dermal fibroblasts (CRL1904), microvascular endothelial cells (HMEC), monocytes (THP-1), and T cells (Jurkat). Cytotoxicity was determined by incubating THP-1, THP-1+ A23187 and JKT cells in RPMI 1640, 1675 in Vitacell, HMEC in EBM, and dermal fibroblasts and HaCaT in DMEM with 10% fetal bovine serum, 1% streptomycin and penicillin for 72 hrs in 96-well microtiter plates, at 37oC in a 5% CO2 incubator with different concentrations of arsenic using fluorescein diacetate (FDA). Cell proliferation in 96-well plates was determined in cultured cells starved by prior incubation for 24 hrs in 1% FBS and exposed for 72 hours, using the 96 cell titer proliferation solution (Promega) assay. Cytotoxicity assays yielded LD50s of 9 μg/mL for HaCaT, 1.5 μg/mL for CRL 1675, 1.5 μg/mL for dendritic cells, 37 μg/mL for dermal fibroblasts, 0.48 μg/mL for HMEC, 50 μg/mL for THP-1 cells and 50 μg/mL for JKT-T cells. The peak proliferation was observed at 6 μg/mL for HaCaT and THP-1 cells, 0.19 μg/mL for CRL 1675, dendritic cells, and HMEC, and 1.5 μg/mL for dermal fibroblasts and Jurkat T cells. These results show that arsenic is toxic at high doses to keratinocytes, fibroblasts, monocytes and T cells, and toxic at lower doses to melanocytes, microvascular endothelial cells and dendritic cells. Proliferation studies showed sub-lethal doses of arsenic to be mitogenic.
Electric Field Effects on 2JHH Spin-Spin Coupling Constants
Authors: Grayson Martin
Published: October 2008

Some calculations of the electric field derivative of the spin-spin coupling constant on molecules in the series CH3F, CH3Cl, CH3Br, CH3I, CH4, CH3Li, CH3Na and CH3K have been presented. The data is broken down into the 4 terms of the Ramsey theory: Fermi contact (FC); diamagnetic spin-orbit (DSO); paramagnetic spinorbit (PSO) and spin-dipolar (SD). The FC term is seen to dominate all the calculated Js and their derivatives presented here. The situation where the FC term does not dominate in other molecules is discussed as a contrast.