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We explore the quantum nature of black holes by introducing an effective framework that takes into account deviations from the classical results. The approach is based on introducing quantum corrections to the classical Schwarzschild geometry in a way that is consistent with the physical scales of the black hole and its classical symmetries. This is achieved by organizing the quantum corrections in inverse powers of a physical distance. By solving the system in a self-consistent way we show that the derived physical quantities, such as event horizons, temperature and entropy can be expressed in a well defined expansion in the inverse powers of the black hole mass. The approach captures the general form of the quantum corrections to black hole physics without requiring to commit to a specific model of quantum gravity., Comment: Revised version matching the published one

Dihydrogenarsenate [H(2)AsO(4)(-), As(V)] or dichromate [Cr(2)O(7)(2-), Cr(VI)] at pH=4.0 showed to be sorbed on a Fe(OH)(x)-polymerin complex and ferrihydrite to a greater extent than on polymerin, the organic polymeric fraction of olive oil mill wastewater (OMW). In particular, the maximum amount (x(m)) of arsenate sorbed on Fe(OH)(x)-polymerin complex was similar to that on ferrihydrite (880.26 and 743.02 mmol kg(-1), respectively), and was much greater than that sorbed on polymerin (384.25 mmol kg(-1)). The sorption of dichromate was to a comparable extent on Fe(OH)(x)-polymerin complex and ferrihydrite (205.90 and 254.88 mmol kg(-1), respectively). Cr(III), a less toxic chromium form, mainly, and Cr(V) were indeed the effective forms sorbed on polymerin (200 mmol kg(-1)), as a consequence of the redox reaction of the strongly toxic Cr(VI) with the CH(2)OH groups of the polysaccharide moiety of this bio-sorbent, according to the data deriving from XPS and DRIFT analyses. The potential exploitation of the selected sorbents for the removal of As(V) or Cr(VI) from aqueous effluents is briefly discussed.

This study investigated the sorption of paraquat and 2,4-D on polymerin, the humic acid-like fraction of olive mill wastewater. Effects of pH, contact time, initial concentration and sorbent dosage on the sorption of both herbicides were studied. The sorption mechanism of paraquat on polymerin was consistent with the ion exchange of this herbicide with Ca, Mg and K natively occurring in the sorbent; in contrast, 2,4-D was bound to polymerin by hydrogen bonding. Simulated wastewaters contaminated with paraquat were purified after three sorption cycles on polymerin renewed at each cycle, at a solid/liquid ratio of 0.5, whereas those containing 2,4-D showed a maximal residue removal of 44% after two sorption cycles at the same ratio. The possible application of this model to other water-soluble herbicides, as well as the possible exploitation of polymerin as a bio-filter for the decontamination of pollution point sources is briefly discussed.

The transformation by an oxidoreductase (a laccase from Rhus vernificera) of a mixture of four phenols (catechol, methylcatechol, m-tyrosol and hydroxytyrosol) that simulates a typical wastewater derived from an olive oil factory was investigated. Results achieved in this study confirm that laccase-mediated transformation of phenols depends on the nature and the initial concentration of the involved phenol, the time course of the reaction, and mainly, on the complexity of the phenolic incubation mixture. Actually, the four phenols each have a completely different response to enzyme action both in terms of quantitative and kinetic transformation. For example, after 24-h incubation, methylcatechol was completely removed, whereas 30% of untransformed hydroxytyrosol and catechol and more than 65% of m-tyrosol were still present in the reaction mixture. A reduction of enzyme activity occurred for all phenols after enzymatic oxidation. No correspondence between phenol transformation and disappearance of enzymatic activity was observed, thus suggesting that different mechanisms are probably involved in the laccase-mediated transformation of the four phenols. The behavior of phenols became more complex when an increasing number of phenols was present in the reaction mixture, and even more so when different concentrations of phenols were used. Competitive effects may arise when more than one phenol is present in the reaction solution and interacts with the enzyme.

A discontinuous fermenter was used to grow the oleaginous yeast Lipomyces starkeyi in the presence of hydrolysates of lignocellulosic wastes from Arundo donax. The lignocellulosic materials were first steam- exploded and subsequently treated with commercial preparations of cellulases and ß-glucosidases, to obtain a mixture of fermentable sugar. A physico-mathematical model was developed to find the optimal condition of production. Specific attention was devoted to the effect of temperature on the growth of L. Starkeyi and on the intracellular accumulation of lipids. The composition of the biodiesel produced was compatible with a satisfactory performance as automotive fuel, in terms of both the resistance to oxidation and the cold performance.

Some saprobe fungi (Phlebia radiata, Trametes versicolor, Coriolopsis rigida, Pycnoporus cinnabarinus, Fomes sclerodermus or Pleurotus pulmonarius) were able to bioconvert the ethyl acetate fraction (DEAF) and the corresponding aqueous exhausted fraction (EAF) of dry olive mill residue (DOR), reducing their phytotoxicity on Lepidium sativum seeds. Large amount of hydroxytyrosol together with other eight monomeric phenols were found in the native DEAF fraction, which represents a good source of antioxidants. P. radiata, T. versicolor and F. sclerodermus caused an effective phytotoxicity reduction of EAF in the concentration range of 25–3 g l 1 . In particular, in the range between 12.5 and 3 g l 1 , the EAF samples inoculated with P. radiata and F. sclerodermus surprisingly stimulated the germinability of L. sativum, suggesting their use as a potential biofertilizer. This is the first report which showed the bioconversion of the above fractions in shorter time with respect to the previous findings concerning DOR. The possible implications of laccase in the decrease of DEAF and EAF phytotoxicity was also discussed. � 2006 Elsevier Ltd. All rights reserved.

Adsorption−desorption of simazine on model systems which closely simulate those encountered in soils [i.e., pure montmorillonite and montmorillonite covered by different amounts of OH−Al species (chlorite-like complexes)] was investigated. The adsorption data were analyzed according to Langmuir and Freundlich equations. Results obtained indicate that the adsorption of simazine was strongly influenced by the charge characteristics of clay minerals and the pH of buffer (3.7 and 5.6). At pH 3.7, simazine was adsorbed in large amounts on montmorillonite, whereas adsorption significantly decreased with increasing amounts of Al(OH)x species on montmorillonite surfaces. When experiments were carried out at pH 5.6, the adsorption of the herbicide on montmorillonite drastically decreased, whereas no severe differences were observed with AM18 (a montmorillonite loading 18 mequiv g-1 M). Desorption tests showed that negligible and very little amounts of simazine were desorbed from montmorillonite and AM18, respectiv...

The interactions between 2,4-D and simazine with inorganic and organic soil colloids affected by adsorption (abiotic) and enzymatic mechanisms (biotic) were investigated. Complex model systems which closely simulate those encountered in soils [i.e. pure montmorillonite, montmorillonite covered by different amounts of OH-Al species (chlorite-like complexes)], were used as adsorbents. 2,4-D gave a negligible adsorption on pure montmorillonite, whereas it was significantly adsorbed on chlorite-like complexes. The larger the OH-Al amounts on clay surfaces, the greater the quantity of 2,4-D adsorbed. An opposite behaviour was observed with simazine, which adsorbed much more on montmorillonite than on chlorite-like complexes. A well characterised laccase from the fungal strain Cerrena unicolor was used as biotic catalyst. The enzyme displayed a lower ability to oxidise 2,4-D and simazine whereas it was extremely efficient in the oxidation of 2,4-DCP (a derivative of 2,4-D) and catechol. The presence of soil colloids or reactive co-substrates differently influenced the enzymatic transformation of 2,4-DCP. The results obtained in this study provided useful information for predicting the behaviour of a xenobiotic substance when entered into soil.

The kinetics and stability of a laccase isolated and purified from the fungal strain Cerrena unicolor were studied. The enzyme was produced in a great yield without inducers. Kinetic parameters were determined by using 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS) as substrate. At high ABTS concentrations (> 10 mM) a substrate inhibition phenomenon appeared and an inhibition constant Ki of 24 mM was determined. The pH- and temperature-profiles as well as the sensitivity of the enzyme to several deactivation agents were almost similar to those observed with laccase from different origins. Freezing-thawing treatment, high temperature, acidic pH (< 3.0) and acetonitrile strongly affected laccase activity. The laccase showed a good ability to oxidize different phenolic substances; a significant enhancing effect was showed by ABTS acting as co-substrate. These results seem to suggest that this new laccase preparation may be suitable for environmental purposes.

The effects of atrazine, carbaryl, glyphosate and paraquat on the activity of jack bean urease, free in solution or immobilized on a clean clay (montmorillonite), an organic compound (tannic acid) or a synthetic organo-mineral [Al(OH) x -tannate and Al(OH) x -tannate-montmorillonite] complexes were studied. For comparison, pesticide influence on urease activity in some soils and soil extracts was investigated, under laboratory conditions. Urease was affected by pesticides to different degrees, depending on its physical state, i.e. if free, immobilized or as total activity in soils or soil extracts. Glyphosate and paraquat enhanced the urease activity of soils (by 1.1–1.4-fold) and soil extracts (by 2.59–6.73-fold). No significant effects were detected on the activity of jack bean urease, either free in solution or absorbed on montmorillonite. Similarly, no influence on the activity of urease immobilized on synthetic organo-mineral complexes was observed with paraquat. Since atrazine and carbaryl, which have low solubility in water, were applied in methanol, the effect of this solvent on urease activity was investigated. The activity of urease in soils and soil extracts was strongly increased by methanol (by 1.48–7.47-fold and by 1.42–11.62-fold, respectively) and carbaryl (by 1.73–2.91-fold). Atrazine partly reduced the increasing effect of methanol. Free and immobilized urease were generally inhibited by methanol and both pesticides (on average −40%), but the extent of inhibition greatly depended on the nature of immobilizing support.

Dry olive mill residue (DOR) from the olive oil production by two phase centrifugation system was fractionated by a consecutive continuous solid–liquid extraction obtaining the EAF, PF, MF and WF fractions with ethyl acetate, n-propanol, methanol and water, respectively. The chemical, chromatographic and mass spectrometric analyses showed EAF, PF and MF to be mainly composed of simple phenols, phenolic acids, flavonoids and glycosilated phenols (glycosides of phenols, secoiridoids and flavonoids), whereas WF was mainly consisting of polymerin, the metal organic polymeric mixture previously identified in olive oil mill waste waters and composed of carbohydrates, melanin, proteins and metals (K, Na, Ca, Mg and Fe). The identification in DOR of oleoside, 6 0 -b-glucopyranosyloleoside and 6 0 -b-rhamnopyranosyl-oleoside, and of its organic polymeric component, known as polymerin, are reported for the first time in this paper. The inoculation of the previously mentioned fractions with saprobe fungi Coriolopsis rigida, Pycnoporus cynnabarinus or Trametes versicolor indicated these fungi to be able to metabolize both the phenols and glycosilated phenols, but not polymerin. In correspondence, EAF, PF, MF and WF, which proved to be toxic on Lepidium sativum, decreased their toxicity after incubation with the selected fungi, WF showing to be also able to stimulate the growth of the selected seeds. The phytotoxicity appeared mainly correlated to the monomeric phenols and, to a lesser extent, to the glycosilated phenols, whereas polymerin proved to be non toxic. However, the laccase activity was not associated with the decrease of phytotoxicity. The valorization of DOR as a producer of high added value substances of industrial and agricultural interest in native form and after their bioremediation for a final objective of the total DOR recycling is also discussed. � 2007 Elsevier Ltd. All rights reserved.

The influence of air-drying on dehydrogenase, invertase, β-glucosidase, urease, phosphatase, arylsulphatase and phenoloxidase activities was measured in three soils affected by anthropogenic activities and in control soils sampled from neighbouring areas. The air-drying changed enzyme activity, but the behaviour was neither site-specific nor enzyme-sensitive. Canonical discriminant analysis of enzymatic activities of both moist fresh and air-dried samples was able to discriminate between altered and unaltered soils irrespective of the site. Numerical alteration indices were developed as a linear function of the seven enzyme activities and the one obtained from fresh sample data was more successful. Air-drying apparently alters in unpredictable ways enzyme activities of soils, which could lead to misinterpretation of results.

Publisher Summary This chapter presents an outline of investigations performed on various aspects of enzymes in soil—namely, (1) enzymes in soil, as an example of “naturally immobilized enzymes,” (2) enzymes in soil, as affected by natural and anthropogenic factors, and (3) enzymes as potential detoxifying agents of polluted systems, including soils, with specific reference to phenolic pollutants. Three enzymes—invertase, phosphatase, and urease—and pure clays (montmorillonite), dirty clays (montmorillonite covered by different amounts of OH–Al species), and tannic acid, were used as representative of inorganic and organic soil components. The influence of metal (Al, Fe, and Mn) species on the interactions between enzymes and tannic acid was examined in the study discussed in the chapter. Synthetic enzyme complexes showed catalytic and stability properties that depended on the matrix and the bonding mechanism involved in their formation. Usually, a reduced activity and a kinetic behavior conforming to Michaelis–Menten kinetics were observed. Various responses in terms of thermal and proteolytic stability were observed. Finally, the potentiality of a laccase, an oxidoreductive enzyme, to detoxify a phenol-polluted system was addressed. The enzyme showed a satisfying efficiency toward different phenolic molecules when acting in the presence of complex system (phenol-soil colloids suspensions).

The influence of four pesticides, e.g. glyphosate, paraquat, atrazine, and carbaryl, on the activities of invertase, urease and phosphatase of twenty-two soils, numbered as 1-22, was investigated. Soils displayed a general variability of enzyme activities with invertase being more abundant than urease and phosphatase in the order listed. The addition of glyphosate and paraquat activated invertase and urease activities in several soils. Increments of invertase activity ranged from a very low increase (+4%) up to +204% in soils 11 and 14, respectively. Smaller increases were measured for urease. A general inhibitory effect (from 5% to 98%) was observed for phosphatase in the presence of glyphosate. The effects of atrazine and carbaryl on the three soil enzymes were evaluated against that exhibited by methanol, the solvent used for their solubilization. In almost all soils, atrazine further inhibited invertase activity with respect to the inhibitory effect shown by methanol. By contrast, consistent activation effects (from 61% to 10217%) were measured for urease with methanol alone and/or methanol-pesticide mixtures. Contradictory results were observed with phosphatase. Similarities found between the results obtained with enzymes in soils and those measured with synthetic enzyme complexes (e.g. free enzymes and/or clay-, organo-, and organo-clay-enzyme complexes) exposed to the same pesticides allowed some relationships between responses of soil enzymes to pesticides and soil properties to be hypothesized.

An Al(OH)(x)-montmorillonite (chlorite) complex (AM(18)) was prepared and 2,4-dichlorophenoxyacetic acid (2,4-D) sorbed to saturation. After several washing cycles the 'strongly sorbed' 2,4-D was 507 mu g g(-1) AM(18). The bioavailability of sorbed 2,4-D was assessed in a minimal salts medium with the AM(18) - 2,4-D as the sole C and energy source. Over a 28-day period a Pseudomonas sp. degraded 23% more of the sorbed 2,4-D than could be accounted for by desorption from AM(18) in the non-inoculated controls. Possible explanations for the increase in bioavailability are presented.

Laccase from Cerrena unicolor catalyses the oxidation of a wide range of aromatic compounds, either xenobiotic or naturally occurring phenols, leading to the formation of polymeric products. These are characterized by their low solubility and often may form precipitates or aggregates. The oxidizing efficiency of the enzyme is strictly dependent on the number of hydroxyl groups and the position of substituents on the phenolic molecules. During the reaction with some substrates, the enzyme is inactivated, because of possible adsorption of laccase molecules on newly formed polyphenols. By contrast, the oxidation of humic precursors (i.e., resorcinol, gallic acid, and pyrogallol) does not influence greatly the residual laccase activity. The triazinic herbicides, triazine and prometryn (2,4-bis(isopropylamino)-6-methylthio-s-triazine), are not substrates of laccase. They, however, inhibit laccase activity assayed with 2,4-dichlorophenol (2,4-DCP) or catechol as substrates. The reduction of substrate oxidation rates is usually accompanied by the retention of higher levels of residual enzymatic activity. These results, together with the slight recovery in laccase activity following dialysis of the assay mixture, provide further evidence that the enzyme may be incorporated into or adsorbed onto polyphenolic products, with a consequent reduction in the concentration of active forms of laccase.

330 women with a median age of 30.15 (+- 9.5) years sought gynecological consultation for advice on contraception and for cervical carcinoma screening. Anamnesis explored the presence of dysuria, dyspareunia, secretions, and pelvic pain, the number of partners, and type of contraceptive used. Endocervical samples were collected by means of tampon and the specimens were analyzed for 48 to 120 hours to find antigens of Chlamydia trachomatis (C.T.) by a solid phase immunoenzymatic test. Peripheral blood samples were also taken from all women to look for antibodies of C.T. and also the indirect immunoperoxidase test was used to search for specific antibodies of C.T. (IgM, IgA, IgE, IgG). The chi-square test was applied for statistical analysis. None of the women who used oral hormonal contraceptives or condoms were infected (presence of antigens and positivity for IgM and/or IgE and/or IgA), however, 36 of 90 IUD users (40%) were infected, 18 of 132 women who used no contraceptives whatsoever (13.7%) were also infected. 91% of the subjects had a single partner. In view of these findings the use of the condom and oral contraceptives is recommended with proper instruction about their potential side effects.

Ultrasound assessment of septum thickness is useful in twin pregnancies for predicting the type of placentation. In fact, its greater or lesser acoustic resonance distinguishes monochorionic or dichorionic pregnancies. This makes adoption of therapeutic measures more secure in the event of pathology involving only one of the two fetuses.

Liquid biofuel is a promising alternative to petroleum-based fossil fuel. Lignocellulosic biomass (LCB) is considered as a potential source of biofuel since it is not food competitive always. Moreover, it has a wide range of sources, such as agriculture residues, forest residues, grass, and energy crops. Though the resources are abundant and readily available all around the world, its contribution in energy sector is not significant. It may be due to the lacking of economically viable and industrially applicable technology. To design and develop sustainable technology, it is urgent to understand the composition, characters, and their refinery process. Therefore this chapter describes the fundamental structure, chemistry, and biorefinery of LCB.

We study a bound state of fractional D3-branes localized inside the world-volume of fractional D7-branes on the orbifold C^3/Z_2 x Z_2. We determine the open string spectrum that leads to N=1 U(N1)xU(N2)xU(N3)xU(N4) gauge theory with matter having the number of D7-branes as a flavor index. We derive the linearized boundary action of the D7-brane on this orbifold using the boundary state formalism and we discuss the tadpole cancellation. After computing the asymptotic expression of the supergravity solution the anomalies of the gauge theory are reproduced., Comment: LaTeX 20 pages, 1 figure, small changes and references added

L’emoglobina (Hb) rappresenta una delle proteine maggiormente studiate in termini di struttura e funzione sia per il ruolo fisiologico svolto, sia perché costituisce un modello ottimale per lo studio dei fenomeni di cooperatività. Nonostante l’elevata similitudine strutturale e funzionale tra le Hb dei mammiferi temperati e le emoglobine di pesci antartici (AFHb), esistono numerose differenze. In particolare, le AFHb presentano due effetti peculiari: l’effetto Root e la formazione dell’emicromo. L’emicromo rappresenta una specie ferrica molecolare esacoordinata a basso spin nella quale si forma un legame tra la catena laterale di un residuo distale di istidina e la sesta posizione di coordinazione del Fe3+(1). L’effetto Root invece si manifesta come una drastica riduzione dell’affinità e della cooperatività per il legame con l’ossigeno a pH acidi (2). Il requisito minimo strutturale affinchè si abbia effetto Root è la formazione, a pH acidi, di un legame a idrogeno interaspartico all’interfaccia α1β2 Asp95á-Asp101â assistito dal residuo Asp99â (3). La presenza della triade di aspartici non è però un requisito sufficiente per l’effetto Root. Infatti la variante naturale dell’Hb umana Potomac (che presenta la mutazione b101Glu→Asp e che quindi possiede la triade di aspartici) non presenta tale effetto avendo addirittura una maggiore affinità per l’ossigeno (4). Allo scopo di acquisire le informazioni necessarie per il trasferimento delle due proprietà tipiche di alcune Hb di pesci a quella umana è stato sviluppato un sistema di produzione ricombinante in E. coli della globina β nella variante naturale Potomac per consentirne un dettagliato studio strutturale. In particolare, si è affrontato il problema dell’inefficiente rimozione da parte dell’ospite batterico della metionina all’estremità N-terminale. Poiché in Hb tetrameriche il residuo N-terminale, di entrambe le catene α e β, gioca un ruolo importante nel modulare l’affinità con l’ossigeno, la mancata rimozione della Met iniziale va a modificare tale affinità. Per ovviare a questo problema è stata costruita una variante N-terminale della globina β, nella quale il residuo di Valina 1 è stato sostituito con una Metionina (β1Val→Met (1)). Per ottenere la variante Potomac è stata effettuata una mutazione a partire dal mutante 1 mediante mutagenesi sito-specifica. Il gene mutato così ottenuto è stato clonato nel vettore di espressione pET22b, generando il plasmide impiegato per trasformare un ceppo di E. coli. Sono state effettuate, quindi, le diverse prove di produzione variando la temperatura del processo ed in presenza di una concentrazione costante di induttore IPTG, di acido δ-amminolevulinico (precursore dell’eme) e di FeCl3. Analisi elettroforetica SDS-PAGE degli omogenati cellulari e delle corrispondenti frazioni insolubili ha evidenziato che la globina prodotta risulta aggregata nei corpi di inclusione dai quali è stato possibile risolubilizzarla con l’impiego di detergenti non denaturanti (5). Bibliografia: 1.Vitagliano L. et al.,(2008)J. Am. Chem. Soc. 130, 10527-35 2.Mazzarella L. et al.,(2006)Proteins: Struct. Funct. Bioinf. 65, 490-8 3.Mazzarella L. et al.,(2006)Proteins: Struct. Funct. Bioinf. 62, 316-21 4.Shih D.T. et al.,(1985)J Biol Chem. 260, 5919-24. 5.Peternel Š. et al., (2007)Biotecnnol Appl Biochem 49,239-6 Parole chiave: emoglobine, Effetto Root, produzione ricombinante Area tematica : Biologia molecolare.