Electrochemical study, on mercury, of a Meta-nitroarylamine derivative of nor-β-lapachone, an antitumor and trypanocidal compound

The electrochemistry of 2,2-dimethyl-(3H)-3-(N-3'-nitrophenylamino)naphtho[1,2- b]furan-4,5-dione ([Q]-PhNO2), on mercury was investigated. The first peak is consistent with a quasi-reversible one-electron reduction of the ortho-quinone, forming [Q•-]-PhNO2, while the second one, bielectronic, corresponds to the simultaneous reduction of the latter radical to a dianion and the nitro group to a nitro radical anion. The second order rate constant, k disp, for the decay of [Q•-]-PhNO2 is 15.188 x 10³ ± 827 mol"1 L s"1 and the t1/2 equals 0.06 s. E¹7Ic values for [Q]-PhNO2 and its precursor, nor-β-lapachone, are similar. The ease of semiquinone generation and its stability are parameters statistically relevant in the correlation biochemical/theoretical aspects.

Preparation of association compound between rhodium(II) citrate and β-cyclodextrin

Inclusion compound of rhodium(II) citrate with β-cyclodextrin in a 1:1 molar ratio was prepared using freeze-drying method. X-ray diffactometry, thermal analysis (TG/DTG/DSC), infrared and ¹H-NMR with ¹H spin lattice relaxation (¹H T1) measurements and 13C techniques were used to characterize the system prepared. The results indicated the formation of inclusion or association compounds between rhodium(II) citrate and β-cyclodextrin.

A Theoretical investigation of a potential high energy density compound 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo[3.1.1.1(2,4)]octane

The B3LYP/6-31G (d) density functional theory (DFT) method was used to study molecular geometry, electronic structure, infrared spectrum (IR) and thermodynamic properties. Heat of formation (HOF) and calculated density were estimated to evaluate detonation properties using Kamlet-Jacobs equations. Thermal stability of 3,6,7,8-tetranitro-3,6,7,8-tetraaza-tricyclo [3.1.1.1(2,4)]octane (TTTO) was investigated by calculating bond dissociation energy (BDE) at the unrestricted B3LYP/6-31G(d) level. Results showed the N-NO2 bond is a trigger bond during the thermolysis initiation process. The crystal structure obtained by molecular mechanics (MM) methods belongs to P2(1)/C space group, with cell parameters a = 8.239 Å, b = 8.079 Å, c = 16.860 Å, Z = 4 and r = 1.922 g cm-3. Both detonation velocity of 9.79 km s-1 and detonation pressure of 44.22 GPa performed similarly to CL-20. According to the quantitative standards of energetics and stability, TTTO essentially satisfies this requirement as a high energy density compound (HEDC).

Synthesis and magnetic properties of heteronuclear 3d-4f compound

A novel heteronuclear 3d-4f compound having formula NdCu3L3·13H2O (where H3L = Schiff base derived from 5-bromosalicylaldehyde and glycylglycine and L³ = C11H8 N2O4Br) was obtained. It was characterized by elemental and thermal analyses and magnetic measurements. The Cu(II)-Nd(III) compound is stable up to 323 K. During dehydration process the water molecules are lost in two stages. The magnetic susceptibility data for this complex change with temperature according to the Curie-Weiss law with theta = -35 K. The magnetic moment values decrease from 5.00µB at 303 K to 4.38µB at 76 K.

Adsorptive removal of harmful organic compound from aqueous solutions

Adsorption is one of the most commonly used methods in water treatment processes. It is attractive due to it easy operation and the availability of a wide variety of commercial adsorbents. This doctoral thesis focuses on investigating and explaining the influence of external phase conditions (temperature, pH, ionic strength, acidity, presence of cosolutes) on adsorption phenomena. In order to cover a wide range of factors and phenomena, case studies were chosen from various fields where adsorption is applied. These include the adsorptive removal of surface active agents (used in cleaning chemicals, for example) from aqueous effluents, the removal of hormones (estradiol) from drinking water, and the adsorption of antibiotics onto silica. The latter can beused to predict the diffusion of antibiotics in the aquatic system if they are released into the environment. Also the adsorption of living cells on functionalized polymers to purify infected water streams was studied. In addition to these examples, the adsorptive separation of harmful compounds from internal water streams within a chemical process was investigated. The model system was removal of fermentation inhibitors from lignocelluloses hydrolyzates. The detoxification of the fermentation broth is an important step in the manufacture of bioethanol from wood, but has not been studied previously in connection with concentrated acid hydrolyzates. New knowledge on adsorption phenomena was generated for all of the applications investigated. In most cases, the results could be explained by combining classical theories for individual phenomena. As an example, it was demonstrated how liquid phase aggregation could explain abnormal-looking adsorption equilibrium data. In addition to the fundamental phenomena, also process performance was of interest. This aspect is often neglected in adsorption studies. It was demonstrated that adsorbents should not be selected for a target application based on their adsorption properties only, but regeneration of the spent adsorbent must be considered. It was found that using a suitable amount of organic co-solvent in the regeneration can significantly improve the productivity of the process.

INTERACTIONS OF BIOCHAR AND ORGANIC COMPOUND FOR SEEDLINGS PRODUCTION OF Magonia pubescens A. St.-Hil.

ABSTRACTThe objective of this study was to test the hypothesis that biochar, applied with cattle manure, promotes better development of seedlings of Magonia pubescens St. Hil. The experiment was conducted at the State University of Mato Grosso, Nova Xavantina, Brazil, in 2011. We used a completely randomized design, with twelve treatments and three replications. The substrates formed by the higher levels of cattle manure plus biochar (30%) provided better results of height, diameter and aerial biomass. However, the Dickson Quality Index has not confirmed the quality of seedlings in these treatments. We also observed that the doses of biochar (20 and 30%) when added separately to the Latosol, are not efficient for the growth improvement of the seedlings. Based on the present results, we validate the hypothesis that substrates formed with a mixture of cattle manure and biochar are effective to improve the production of seedlings of M. pubescens.

Hybrid warfare – just a twist of compound warfare? : views on warfare from the United States Armed Forces perspective

The wars the Western armies are involved with today are different from those that were fought in the end of 20th century. To explain this change, the Western military thinkers have come up with various different types of definitions of warfare over the last 30 years, each describing the tendencies involved in the conflicts of the time. The changing nature of conflicts surfaced a new term – hybrid warfare. The term was to describe and explain the multi-modality and complexity of modern day conflict. This thesis seeks the answer for the question: what is the development of thought behind hybrid warfare? In this thesis the Vietnam War (1965-1975) is used as an example of compound warfare focusing on the American involvement in the war. The Second Lebanon War (2006) serves as an example of hybrid warfare. Both case studies include an irregular opposing force, namely National Liberation Front in Vietnam War and Hezbollah in the Second Lebanon War. These two case studies are compared with the term full spectrum operations introduced in the current U.S. Department of Army Field Manual No. 3-0 Operations to see the differences and similarities of each term. The perspective of this thesis is the American point of view. This thesis concludes that hybrid warfare, compound warfare and full spectrum operations are very similar. The first two terms are included in the last one. Although hybrid warfare is not officially defined, it will most likely remain to be used in the discussion in the future, since hybrid wars and hybrid threats are officially accepted terms.

Unusual bismuth-containing surface layers of III-V compound semiconductors

The understanding and engineering of bismuth (Bi) containing semiconductor surfaces are signi cant in the development of novel semiconductor materials for electronic and optoelectronic devices such as high-e ciency solar cells, lasers and light emitting diodes. For example, a Bi surface layer can be used as a surfactant which oats on a III-V compound-semiconductor surface during the epitaxial growth of IIIV lms. This Bi surfactant layer improves the lm-growth conditions if compared to the growth without the Bi layer. Therefore, detailed knowledge of the properties of the Bi/III-V surfaces is needed. In this thesis, well-de ned surface layers containing Bi have been produced on various III-V semiconductor substrates. The properties of these Bi-induced surfaces have been measured by low-energy electron di raction (LEED), scanning-tunneling microscopy and spectroscopy (STM), and synchrotron-radiation photoelectron spectroscopy. The experimental results have been compared with theoretically calculated results to resolve the atomic structures of the studied surfaces. The main ndings of this research concern the determination of the properties of an unusual Bi-containing (2×1) surface structure, the discovery and characterization of a uniform pattern of Bi nanolines, and the optimization of the preparation conditions for this Bi-nanoline pattern.

Response threshold to aversive stimuli in stimulated early protein-malnourished rats

Two animal models of pain were used to study the effects of short-term protein malnutrition and environmental stimulation on the response threshold to aversive stimuli. Eighty male Wistar rats were used. Half of the pups were submitted to malnutrition by feeding their mothers a 6% protein diet from 0 to 21 days of age while the mothers of the other half (controls) were well nourished, receiving 16% protein. From 22 to 70 days all rats were fed commercial lab chow. Half of the animals in the malnourished and control groups were maintained under stimulating conditions, including a 3-min daily handling from 0 to 70 days and an enriched living cage after weaning. The other half was reared in a standard living cage. At 70 days, independent groups of rats were exposed to the shock threshold or to the tail-flick test. The results showed lower body and brain weights in malnourished rats when compared with controls at weaning and testing. In the shock threshold test the malnourished animals were more sensitive to electric shock and environmental stimulation increased the shock threshold. No differences due to diet or environmental stimulation were found in the tail-flick procedure. These results demonstrate that protein malnutrition imposed only during the lactation period is efficient in inducing hyperreactivity to electric shock and that environmental stimulation attenuates the differences in shock threshold produced by protein malnutrition

Contrast sensitivity to angular frequency stimuli is higher than that for sinewave gratings in the respective middle range

This study compares contrast thresholds for sinewave gratings, or spatial frequencies (1/CSF) with contrast thresholds for angular frequencies (1/aCSF) and for radial frequencies, or J0 targets (1/rCSF). Observers had to differentiate between one of these frequency stimuli and a stimulus at mean luminance within a forced-choice procedure. All measurements were made with the same equipment, methods and subjects. Our results show higher sensitivity to, or lower thresholds for, angular frequencies when compared to either sinewave gratings or J0 targets. Contrast values in arbitrary units, in the lower threshold range for angular frequencies, were about half those required to differentiate sinewave gratings from mean luminance in its most sensitive range

Inhibitory effects in the detection of 1 cpd jo targets superimposed to angular frequency stimuli or sinewave gratings

Independence among channels processing different aspects of spatial information, including orthogonal stimuli, has been generally assumed in the literature. We tested independence between the processing of jo targets and the processing of either vertical sinusoidal gratings or angular frequency stimuli with suprathreshold summation. We found the detection of a jo target at 1 cpd to be affected in an inhibitory fashion by either background angular frequencies in the range of 3-96 cycles or sinewave gratings in the range of 0.8-3.0 cpd. These results demonstrate interactions both among orthogonal stimuli and among channels processing vertical sinewave gratings and jo target stimuli. Our discussion focuses on the hypothesis of frequency decomposition in polar coordinates

Paradoxical increase of exploratory behavior in the elevated plus-maze by rats exposed to two kinds of aversive stimuli

Albino rats were submitted to a 24-h period of social isolation (individual housing) combined with 0, 1, 2 or 3 twenty-four-hour periods of exposure to different vivaria (novelty) and tested in the elevated plus-maze. Results, reported as mean ± SEM for N = 12, show that the time (in seconds) spent in the open arms by rats exposed to novelty for 0, 1, 2 and 3 days was 28.3 ± 4.4, 31.6 ± 3.2, 29.1 ± 3.5 and 25.0 ± 3.3, respectively, when grouped in the same vivarium; 29.6 ± 2.7, 7.6 ± 2.1, 9.6 ± 4.4 and 28.5 ± 3.7 when grouped in different vivaria; 2.9 ± 1.1, 1.8 ± 1.0, 2.7 ± 1.1 and 0 ± 0 when isolated in the same vivarium, and 2.6 ± 1.1, 31.5 ± 8.2, 24.8 ± 4.2 and 0 ± 0 when isolated in different vivaria. The number of entries into the open and closed arms followed a similar trend. This indicates that, separately, both exposure to novelty and isolation are aversive manipulations. Paradoxically, when novelty was combined with a concomitant 24-h period of social isolation prior to testing, the decrease in exploratory behavior caused by either of the two aversive manipulations alone was reverted. These results are indicative that less intense anxiety triggers mechanisms mediating less energetic behavior such as freezing, while higher levels trigger mechanisms mediating more vigorous action, such as flight/fight behavior, since the combination of two aversive situations resulted in more exploratory behavior than with either alone. They are also suggestive of habituation to the effects of novelty, since exposure to it for 3 days produced exploratory behavior similar to that of controls

Signaled two-way avoidance learning using electrical stimulation of the inferior colliculus as negative reinforcement: effects of visual and auditory cues as warning stimuli

The inferior colliculus is a primary relay for the processing of auditory information in the brainstem. The inferior colliculus is also part of the so-called brain aversion system as animals learn to switch off the electrical stimulation of this structure. The purpose of the present study was to determine whether associative learning occurs between aversion induced by electrical stimulation of the inferior colliculus and visual and auditory warning stimuli. Rats implanted with electrodes into the central nucleus of the inferior colliculus were placed inside an open-field and thresholds for the escape response to electrical stimulation of the inferior colliculus were determined. The rats were then placed inside a shuttle-box and submitted to a two-way avoidance paradigm. Electrical stimulation of the inferior colliculus at the escape threshold (98.12 ± 6.15 (A, peak-to-peak) was used as negative reinforcement and light or tone as the warning stimulus. Each session consisted of 50 trials and was divided into two segments of 25 trials in order to determine the learning rate of the animals during the sessions. The rats learned to avoid the inferior colliculus stimulation when light was used as the warning stimulus (13.25 ± 0.60 s and 8.63 ± 0.93 s for latencies and 12.5 ± 2.04 and 19.62 ± 1.65 for frequencies in the first and second halves of the sessions, respectively, P<0.01 in both cases). No significant changes in latencies (14.75 ± 1.63 and 12.75 ± 1.44 s) or frequencies of responses (8.75 ± 1.20 and 11.25 ± 1.13) were seen when tone was used as the warning stimulus (P>0.05 in both cases). Taken together, the present results suggest that rats learn to avoid the inferior colliculus stimulation when light is used as the warning stimulus. However, this learning process does not occur when the neutral stimulus used is an acoustic one. Electrical stimulation of the inferior colliculus may disturb the signal transmission of the stimulus to be conditioned from the inferior colliculus to higher brain structures such as amygdala

Compound 48/80, a histamine-depleting agent, blocks the protective effect of morphine against electroconvulsive shock in mice

We have shown that morphine has an anticonvulsive effect against maximal electroconvulsive shock (MES) in mice, and this effect is antagonized by histamine H1-receptor antagonists. Brain histamine is localized both in neurons and in mast cells, and morphine is known to enhance the turnover of neuronal histamine and to release histamine from mast cells. In the present experiments, compound 48/80 was injected chronically (0.5 mg/kg on day 1, 1 mg/kg on day 2, 2 mg/kg on day 3, 3 mg/kg on day 4, and 4 mg/kg on day 5, twice daily, ip) to deplete mast cell contents. Morphine (0.001-10 mg/kg, ip; N = 20) produced a dose-dependent anticonvulsive effect against MES seizure in mice with non-depleted mast cells, whereas it did not exert any anticonvulsive effect in mice with depleted mast cells. These results indicate that morphine produces its anticonvulsive effect against maximal electroconvulsive shock in mice by liberating histamine from mast cells.

Effects of terpineol on the compound action potential of the rat sciatic nerve

Terpineol, a volatile terpenoid alcohol of low toxicity, is widely used in the perfumery industry. It is an important chemical constituent of the essential oil of many plants with widespread applications in folk medicine and in aromatherapy. The effects of terpineol on the compound action potential (CAP) of rat sciatic nerve were studied. Terpineol induced a dose-dependent blockade of the CAP. At 100 µM, terpineol had no demonstrable effect. At 300 µM terpineol, peak-to-peak amplitude and conduction velocity of CAP were significantly reduced at the end of 180-min exposure of the nerve to the drug, from 3.28 ± 0.22 mV and 33.5 ± 7.05 m/s, respectively, to 1.91 ± 0.51 mV and 26.2 ± 4.55 m/s. At 600 µM, terpineol significantly reduced peak-to-peak amplitude and conduction velocity from 2.97 ± 0.55 mV and 32.8 ± 3.91 m/s to 0.24 ± 0.23 mV and 2.72 ± 2.72 m/s, respectively (N = 5). All these effects developed slowly and were reversible upon 180-min washout.