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See detailMechanics of Breathing in Goats
Bakima, M.; Gustin, Pascal ULg; Lekeux, Pierre ULg et al

in Research in Veterinary Science (1988), 45(3), 332-336

Common pulmonary function tests used in man and domestic mammals were adapted to the goat. Requirements for intrathoracic pressure record and pulmonary function investigation were determined. The ... [more ▼]

Common pulmonary function tests used in man and domestic mammals were adapted to the goat. Requirements for intrathoracic pressure record and pulmonary function investigation were determined. The elastance of the mid-thoracic portion of the oesophagus was measured in 17 healthy goats. The calculated percentage error in identifying the endoesophageal intrathoracic pressure decreased with somatic growth, and was found to be smaller than 2 per cent for adult goats. The location of the oesophageal balloon catheter used to measure the intrathoracic pressure was standardised. The following regression equation calculated between the length of catheter (Lcat) and the thoracic circumference (TC) was found: Lcat (cm) = 6.19 +/- 0.7163 X TC (cm) (R2 = 0.96). The influence of the dead space of a face mask on respiration pattern and arterial blood gas were studied. There were no significant changes in arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2), pHa, breathing frequency and intrathoracic pressures. The influence of head and neck position was investigated. Upper airway resistance (Ruaw), measured with the head in a normal position did not significantly differ from values obtained with the head in a horizontal position. Ruaw measured with the head in a vertical position was considerably increased. Arterial blood gas tension and pulmonary mechanics were measured to assess the reproducibility of pulmonary function measurements. Variability in blood gas tension, tidal volume and minute volume is small. The variability of peak to peak intrathoracic pressure change (max delta Plp), dynamic lung compliance (Cdyn), total pulmonary resistance (RL) and Rt were relatively large. [less ▲]

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See detailMechanics of breathing in resting and exercising animals
Lekeux, Pierre ULg; Art, Tatiana ULg

in Lekeux, Pierre (Ed.) Pulmonary Function in Healthy, Exercising and Diseased Animals (1993)

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See detailThe mechanics of the gravid uterus. II. Global myometrial activity and its pharmacology
Lambotte, R.; Foidart, Jean-Michel ULg; Lecomte, J.

in Revue Médicale de Liège (1977), 32(12), 369-77

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See detailThe Mechanics of the Mirage. Postwar American Poetry
Delville, Michel ULg; Pagnoulle, Christine ULg

Book published by L3 (2000)

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See detailMechanics of the pregnant uterus. I. Mechanics properly told
Foidart, Jean-Michel ULg; Lambotte, R.; Lecomte, J.

in Revue Médicale de Liège (1977), 32

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See detailMechanics of the Respiratory System in Healthy Newborn Calves Using Impulse Oscillometry
Uystepruyst, Christophe; Reinhold, Petra; Coghe, Joost et al

in Research in Veterinary Science (2000), 68(1), 47-55

Arterial blood gases, acid-base balance and respiratory function tests using impulse oscillometry (IOS) were performed on 40 clinically healthy newborn calves during the first 24 hours of life to evaluate ... [more ▼]

Arterial blood gases, acid-base balance and respiratory function tests using impulse oscillometry (IOS) were performed on 40 clinically healthy newborn calves during the first 24 hours of life to evaluate their respiratory adaptation to extrauterine life. Gas exchange efficiency of the lung was significantly improved with time and was accompanied by the correction of the mixed acidosis observed at birth and by significant changes in respiratory mechanics. Major changes were detected within the first 6 hours. The significant decrease in resistance (R) and the increase in reactance (X) with time, demonstrate the improvement in respiratory mechanics of both upper and lower airways, and reflect the increase in lung volume, the improved lung tissue elasticity and/or distribution of the ventilation. Respiratory mechanical, arterial blood gases and acid-base balance data provided in this study describe a successful respiratory adaptation to extrauterine life in healthy newborn calves. [less ▲]

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See detailMechanics of unsaturated soils
Laloui, Lyesse; Nuth, Mathieu; François, Bertrand ULg

in Laloui, Lyesse (Ed.) Mechanics of unsaturated materials (2010)

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See detailThe mechanism behind internally generated centennial-to-millennial scale climate variability in an earth system model of intermediate complexity
Friedrich, T.; Timmermann, A.; Menviel, L. et al

in Geoscientific Model Development (2010), 3(2), 377--389

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See detailMechanism for the Appearance of H+ by Electroionization of CH4. A Surprisal Analysis.
Momigny, J.; Locht, Robert ULg; Caprace, G.

in Chemical Physics (1986), 102

Previous experimental results on the threshold energy and on the energy range of the first wide translational energy distribution of H+, resulting from the electron impact on CH4, are interpreted. The ... [more ▼]

Previous experimental results on the threshold energy and on the energy range of the first wide translational energy distribution of H+, resulting from the electron impact on CH4, are interpreted. The translational energy surprisal of this distribution has been evaluated with respect to a statistically calculated one. The surprisal plot shows a fourth power dependence on fT with a negative slope associated with a large DeltaS/exc value of about 4 eu. An "a priori" calculated P(ET/E) distribution, including four constraints, fits fairly well the observed translational energy distribution. [less ▲]

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See detailMechanism of action of a lipophilic salicylic acid derivative on normal skin.
Leveque, J.-L.; Corcuff, P.; Rougier, A. et al

in European Journal of Dermatology (2002), 12(4), -

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See detailMechanism of action of DD-peptidases: role of asparagine-161 in the Streptomyces R61 DD-peptidase.
Wilkin, J M; Jamin, M; Joris, Bernard ULg et al

in Biochemical Journal (1993), 293 ( Pt 1)

The role of residue Asn-161 in the interaction between the Streptomyces R61 DD-peptidase and various substrates or beta-lactam inactivators was probed by site-directed mutagenesis. The residue was ... [more ▼]

The role of residue Asn-161 in the interaction between the Streptomyces R61 DD-peptidase and various substrates or beta-lactam inactivators was probed by site-directed mutagenesis. The residue was successively replaced by serine and alanine. In the first case, acylation rates were mainly affected with the peptide and ester substrates but not with the thiol-ester substrates and beta-lactams. However, the deacylation rates were decreased 10-30-fold with the substrates yielding benzoylglycyl and benzoylalanyl adducts. The Asn161Ala mutant was more generally affected, although the acylation rates with cefuroxime and cefotaxime remained similar to those observed with the wild-type enzyme. Surprisingly, the deacylation rates of the benzoylglycyl and benzoylalanyl adducts were very close to those observed with the wild-type enzyme. The results also indicate that the interaction with the peptide substrate and the transpeptidation reaction were more sensitive to the mutations than the other reactions studied. The results are discussed and compared with those obtained with the Asn-132 mutants of a class A beta-lactamase. [less ▲]

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See detailThe mechanism of action of DD-peptidases: the role of Threonine-299 and -301 in the Streptomyces R61 DD-peptidase.
Wilkin, J M; Dubus, Alice ULg; Joris, Bernard ULg et al

in Biochemical Journal (1994), 301 ( Pt 2)

The side chains of residues Thr299 and Thr301 in the Streptomyces R61 DD-peptidase have been modified by site-directed mutagenesis. These amino acids are part of a beta-strand which forms a wall of the ... [more ▼]

The side chains of residues Thr299 and Thr301 in the Streptomyces R61 DD-peptidase have been modified by site-directed mutagenesis. These amino acids are part of a beta-strand which forms a wall of the active-site cavity. Thr299 corresponds to the second residue of the Lys-Thr(Ser)-Gly triad, highly conserved in active-site beta-lactamases and penicillin-binding proteins (PBPs). Modification of Thr301 resulted only in minor alterations of the catalytic and penicillin-binding properties of the enzyme. No selective decrease of the rate of acylation was observed for any particular class of compounds. By contrast, the loss of the hydroxy group of the residue in position 299 yielded a seriously impaired enzyme. The rates of inactivation by penicillins were decreased 30-50-fold, whereas the reactions with cephalosporins were even more affected. The efficiency of hydrolysis against the peptide substrate was also seriously decreased. More surprisingly, the mutant was completely unable to catalyse transpeptidation reactions. The conservation of an hydroxylated residue in this position in PBPs is thus easily explained by these results. [less ▲]

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See detailThe Mechanism of Action of DD-Peptidases: The Role of Tyrosine-159 in the Streptomyces R61 DD-Peptidase
Wilkin, Jean-Marc; Jamin, Marc; Damblon, Christian ULg et al

in Biochemical Journal (1993), 291(Part 2), 537-544

Tyrosine-159 of the Streptomyces R61 penicillin-sensitive DD-peptidase was replaced by serine or phenylalanine. The second mutation yielded a very poorly active protein whose rate of penicillin binding ... [more ▼]

Tyrosine-159 of the Streptomyces R61 penicillin-sensitive DD-peptidase was replaced by serine or phenylalanine. The second mutation yielded a very poorly active protein whose rate of penicillin binding was also drastically decreased, except for the reactions with nitrocefin and methicillin. The consequences of the first mutation were more surprising, since a large proportion of the thiolesterase activity was retained, together with the penicillin-binding capacity. Conversely, the peptidase properties was severely affected. In both cases, a drastic decrease in the transferase activity was observed. The results are compared with those obtained by mutation of the corresponding residue in the class A beta-lactamase of Streptomyces albus G. [less ▲]

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See detailMechanism of action of free or incorporated into liposomes cis-DDPt : a comparative study in Ehrlich tumour cells
Gillet, Marie-Claire ULg; Houssier, Claude ULg; weber, georges et al

in Hacher, M. P.; Douple, F. B.; Krakoff, I. M. (Eds.) Platinum Coordination Complexes in Cancer Chemotherapy (1984)

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See detailMechanism of action of Tamoxifen
Charlier, Corinne ULg

Conference (1995)

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See detailMechanism of action of β-lactamases and DD-peptidases
Frère, Jean-Marie ULg; Joris, Bernard ULg; Jacob, Françoise et al

in Pandit, U.K.; Alderweireldt, F.C. (Eds.) Bioorganic Chemistry in Healthcare and Technology (1991)

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See detailMechanism of acyl transfer by the class A serine β-lactamase of Streptomyces albus G
Lamotte-Brasseur, Josette; Dive, Georges ULg; Dideberg, Otto et al

in Biochemical Journal (1991), 279(Pt 1), 213-221

Optimization by energy minimization of stable complexes occurring along the pathway of hydrolysis of benzylpenicillin and cephalosporin C by the Streptomyces albus G beta-lactamase has highlighted a ... [more ▼]

Optimization by energy minimization of stable complexes occurring along the pathway of hydrolysis of benzylpenicillin and cephalosporin C by the Streptomyces albus G beta-lactamase has highlighted a proton shuttle that may explain the catalytic mechanism of the beta-lactamases of class A. Five residues, S70, S130, N132, T235 and A237, are involved in ligand binding. The gamma-OH group of T235 and, in the case of benzylpenicillin, the gamma-OH group of S130 interact with the carboxylate group, on one side of the ligand molecule. The side-chain NH2 group of N132 and the carbonyl backbone of A237 interact with the exocyclic CONH amide bond, on the other side of the ligand. The backbone NH groups of S70 and A237 polarize the carbonyl group of the scissile beta-lactam amide bond. Four residues, S70, K73, S130 and E166, and two water molecules, W1 and W2, perform hydrolysis of the bound beta-lactam compound. E166, via W1, abstracts the proton from the gamma-OH group of S70. While losing its proton, the O-gamma atom of S70 attacks the carbonyl carbon atom of the beta-lactam ring and, concomitantly, the proton is delivered back to the adjacent nitrogen atom via W2, K73 and S130, thus achieving formation of the acyl-enzyme. Subsequently, E166 abstracts a proton from W1. While losing its proton, W1 attacks the carbonyl carbon atom of the S70 ester-linked acyl-enzyme and, concomitantly, re-entry of a water molecule W'1 replacing W1 allows E166 to deliver the proton back to the same carbonyl carbon atom, thus achieving hydrolysis of the beta-lactam compound and enzyme recovery. The model well explains the differences found in the kcat. values for hydrolysis of benzylpenicillin and cephalosporin C by the Streptomyces albus G beta-lactamase. It also explains the effects caused by site-directed mutagenesis of the Bacillus cereus beta-lactamase I [Gibson, Christensen [less ▲]

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See detailMechanism of amyloid fibril formation by human lysozyme and VHHs
Dumoulin, Mireille ULg; Chavignon, Chloé ULg

Conference (2011, January)

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See detailMechanism of Collisional Heating in Electrospray Mass Spectrometry: Ion Trajectory Calculations
Hoxha, Antuan; Collette, Caroline ULg; De Pauw, Edwin ULg et al

in Journal of Physical Chemistry A (2001), 105

To simulate the multicollisional heating process taking place in the intermediate pressure region of an electrospray source, ion trajectory calculations have been preformed by introducing in the SIMION ... [more ▼]

To simulate the multicollisional heating process taking place in the intermediate pressure region of an electrospray source, ion trajectory calculations have been preformed by introducing in the SIMION program a subroutine for handling the collision dynamics. The simulated internal energy distributions are compared with already available experimental distributions obtained by the "survival ion yield" method. [less ▲]

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See detailMechanism of Colon Cancer Cell Apoptosis Mediated by Pyropheophorbide-a Methylester Photosensitization
Matroule, Jean-Yves; Carthy, Chris M; Granville, David J et al

in Oncogene (2001), 20

Pyropheophorbide-a methylester (PPME) is a second generation of photosensitizers used in photodynamic therapy (PDT). We demonstrated that PPME photosensitization triggered apoptosis of colon cancer cells ... [more ▼]

Pyropheophorbide-a methylester (PPME) is a second generation of photosensitizers used in photodynamic therapy (PDT). We demonstrated that PPME photosensitization triggered apoptosis of colon cancer cells as measured by using several classical parameters such as DNA laddering, PARP cleavage, caspase activation and mitochondrial release of cytochrome c. Preincubation of cells with N-acetyl cysteine (NAC) or pyrolidine dithiocarbamate (PDTC) protected against apoptosis mediated by PPME photosensitization showing that reactive oxygen species (ROS) are involved as second messengers. On the other hand, photosensitization carried out in the presence of deuterium oxide (D2O) which enhances singlet oxygen (1O2) lifetime only increases necrosis without affecting apoptosis. Since PPME was localized in the endoplasmic reticulum (ER)/Golgi system and lysosomes, other messengers than ROS were tested such as calcium, Bid, Bap31, phosphorylated Bcl-2 and caspase-12 but none was clearly identified as being involved in triggering cytochrome c release from mitochondria. On the other hand, we demonstrated that the transduction pathways leading to NF-kappaB activation and apoptosis were clearly independent although NF-kappaB was shown to counteract apoptosis mediated by PPME photosensitization. [less ▲]

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