Electronic structure and magnetic coupling of two dinuclear trigonal bipyramidal cobalt(II) complexes

The EPR spectra of zinc-doped (bis(N-methylsalicylaldiminato)cobalt(II), (Zn, Co) SALMe, which was found to be dinuclear, and of zinc-doped bis(N,N-bis(2-(diethylamino)ethyl)-2-hydroxyethylamino-O)dicobalt(II)diperchlorate, (Zn, Co)n₃o, were recorded at liquid helium temperature and X-band frequency.The polycrystalline powder spectra of (Zn, Co)SALMe were interpreted within an effective S = 1/2 spin hamiltonian formalism with g₁ = 1.8, g₂ = 2.7, g₃ = 6.2, while those of (Zn, Co)n₃o showed only one band at G= 6.9. The single crystal spectra for the latter yielded g₁ = 0.31(4), g₂ = 0.84(4), g₃ = 6.86(2). The electronic structure of the complexes was calculated using the AOM, and the lowest Kramers doublet for CoSALMe was found to be ±1/2 while a ±3/2 doublet was found for Con₃o. The temperature dependence of the magnetic susceptibility of CoSALMe was measured between 295 and 4.2 K. The data were fitted with two different methods which either took into account or neglected the zero-field splitting of single ions. The coupling was found to be antiferromagnetic with J = 9.8(2) cm^-1 (J is defined through the hamiltonian = JS₁·S₂). The extent of the magnetic interaction between the metal ions for both the complexes was discussed on the basis of a structural analysis.     

Effect of oral hygiene education and motivation on removable partial denture wearers: longitudinal study

Objectives: The purpose of this study was to determine the effect of two different preventive oral hygiene education and motivation programmes on the plaque and gingival index, as well as denture hygiene of patients provided with removable partial denture (RPD) during a 12‐month follow‐up. Material and methods: A total of 53 partially edentulous patients were recruited for this study. The presence or absence of plaque and gingival bleeding by gentle probing was scored on all tooth surfaces at the preliminary visit. The plaque and gingival indexes were measured using the Löe index. Following treatment, the patients were randomly divided into three groups. In Control Group I, subjects were instructed to continue their personal oral hygiene routine. In Group II, participants were given verbal instructions and a self‐educational manual on oral hygiene without illustrations. In Group III, oral hygiene guidance was delivered using a combination of verbal instructions and a self‐teaching manual. To evaluate the effect of the different modes of instruction, the presence or absence of plaque and gingival bleeding was scored on all tooth surfaces (day zero examination) and re‐examined 7, 15 and 30 days, 3, 6 and 12 months following RPD placement. The state of denture hygiene was evaluated 7, 15 and 30 days and 3, 6 and 12 months following rehabilitation. Parametric statistics was applied to dental plaque and gingival indexes. For accumulation of plaque and calculus on the RPD, non‐parametric statistic was applied. Results: The frequency of plaque found during the preliminary visit was higher than that found in the other periods. With regard to gingival index, significant difference was found between the preliminary visit examination and other periods. There was a significant difference in the plaque accumulation on the denture surface between groups I and III. Conclusion: The different methods of oral hygiene instruction used in this study indicate that the type of education was not of significant importance.     

The mitochondrial permeability transition pore: an evolving concept critical for cell life and death

In this review, we summarize current knowledge of perhaps one of the most intriguing phenomena in cell biology: the mitochondrial permeability transition pore (mPTP). This phenomenon, which was initially observed as a sudden loss of inner mitochondrial membrane impermeability caused by excessive calcium, has been studied for almost 50 years, and still no definitive answer has been provided regarding its mechanisms. From its initial consideration as an in vitro artifact to the current notion that the mPTP is a phenomenon with physiological and pathological implications, a long road has been travelled. We here summarize the role of mitochondria in cytosolic calcium control and the evolving concepts regarding the mitochondrial permeability transition (mPT) and the mPTP. We show how the evolving mPTP models and mechanisms, which involve many proposed mitochondrial protein components, have arisen from methodological advances and more complex biological models. We describe how scientific progress and methodological advances have allowed milestone discoveries on mPTP regulation and composition and its recognition as a valid target for drug development and a critical component of mitochondrial biology.     

The effect of long‐term disinfection procedures on hardness property of resin denture teeth

doi: 10.1111/j.1741‐2358.2011.00520.x The effect of long‐term disinfection procedures on hardness property of resin denture teeth Objective: The aim of the study was to evaluate the effect of long‐term disinfection procedures on the Vickers hardness (VHN) of acrylic resin denture teeth. Material and methods: Five acrylic resin denture teeth (Vipi Dent Plus‐V, Trilux–T, Biolux‐B, Postaris‐P and Artiplus‐A) and one composite resin denture teeth (SR‐Orthosit‐O) were embedded in heat‐polymerised acrylic resin within polyvinylchloride tubes. Specimens were stored in distilled water at 37°C for 48 h. Measurements of hardness were taken after the following disinfection procedures: immersion for 7 days in 4% chlorhexidine gluconate or in 1% sodium hypochlorite (CIm and HIm group, respectively) and seven daily cycles of microwave sterilisation at 650 W for 6 min (MwS group). In the WIm group, specimens were maintained in water during the time used to perform the disinfection procedures (7 days). Data were analysed with anova followed by the Bonferroni procedure (α = 0.01). Results: Microwave disinfection decreased the hardness of all acrylic resin denture teeth (p < 0.001). Immersion for 7 days in 4% chlorhexidine gluconate or distilled water had significant effect on the hardness of the acrylic resin denture teeth A (p < 0.01), and 1% sodium hypochlorite on teeth T (p < 0.01). All disinfection procedures decrease the hardness of the composite resin denture teeth (p < 0.01). Teeth O exhibited the highest and teeth V the lowest hardness values in the control group (p < 0.01). Conclusions: Disinfection procedures changed the hardness of resin denture teeth.     

Water Mobility and Distribution in Green Coffee Probed by Time-Domain Nuclear Magnetic Resonance

Water distribution in green coffee was studied by means of pulsed nuclear magnetic resonance (NMR). Hydration experiments for relaxometry measurements were performed by adding either H₂O or D₂O to dried green coffee beans up to 35% (dry basis) or, alternatively, by moisture absorption in a controlled humidity environment. The CPMG experimental relaxation decay curves were acquired using a benchtop time-domain NMR analyzer at each hydration level and as a function of time. All NMR data were fitted according to the Laplace inversion approach to obtain the proton mobility distributions of water in the hydrated beans. By comparing the T ₂ relaxograms of the hydrated beans with the ones observed in the untreated raw beans, it was found that up to ??10% water exhibits a rather restricted proton mobility. Hydration experiments carried out with D₂O highlighted the contribution of the chemical exchange between the water protons and those of the solid matrix to the overall NMR signal. A possible interpretation of the data in terms of the antiplasticizer and plasticizer effect of water is offered.     

Rat liver lowM r phosphotyrosine protein phosphatase isoenzymes: Purification and amino acid sequences

Two lowM _r phosphotyrosine protein phosphatases have been isolated from rat liver. The enzymes were previously known as lowM _r acid phosphatases, but several recent studies have demonstrated that this family of enzymes possesses specific phosphotyrosine protein phosphatase activity. We determined the complete amino acid sequences of the two isoenzymes and named them AcP1 and AcP2. Both consist of 157 amino acid residues, are acetylated at the NH₂-terminus, and have His as the COOH-terminus. The molecular weights calculated from the sequences are 18,062 for AcP1 and 17,848 for AcP2. They are homologous except in the 40–73 zone, where about 50% of residues are different. This fact suggests that the two isoenzymes are produced by an alternative splicing mechanism. There is no homology between these two isoenzymes and the receptor-like phosphotyrosine protein phosphatases LAR, CD45, human placenta PTPase 1B, and rat brain PTPase-1. AcP1 and AcP2 are also distinct from rat liver PTPase-1 and PTPase-2, since these last enzymes have higher molecular weights. AcP1 differs from AcP2 with respect to (1) substrate affinity and (2) its sensitivity to activators and inhibitors, thus suggesting a their different physiological function.     

Short Communication: Urinary excretion of glutamine transaminase K as an early index of mercuric chloride-induced nephrotoxicity

The possibili that urinary glutamine transaminase K activity might be a marker of a proximal tubule segment-specific response to mercuric chloride was investigated in male rats after a single i.p. injection in time-course and dose-response experiments. Urinary total proteins and angiotensin converting enzyme activity were determined simultaneously. Urinary indices showed an early increase (within 5 h of treatment) of total proteins and angiotensin converting enzyme, whereas glubmine transaminase K increased 10 h after treatment. The peak of all these indices was observed 24 h after mercuric chloride injection. The lowest dose that induced a significant increase in proteins and enzymes was 0.25 mg kg^-1; in addition, a dose-response effect was observed. Glutamine transaminase K appeared to be an early and sensitive index of response of mercuric chloride effects, similar to total proteins and angiotensin converting enzyme. It is suggested that this enzyme is mainly localized in the 'pars recta' of the proximal tubule. Therefore glutamine transaminase K might be a segment-specific marker for the detection of damage localized in this portion of the proximal tubule.     

Enhancement of γ-Aminobutyric Acid Binding by the Anxiolytic β-Carbolines ZK 93423 and ZK 91296

The effects of two anxiolytic beta-carboline derivatives, ZK 93423 and ZK 91296, on the binding of gamma-[3H]aminobutyric acid ([3H]GABA) to brain membrane preparations from rat cerebral cortex were examined. ZK 93423 concentration-dependently enhanced the specific binding of [3H]GABA, with a maximal increase of 45% above control at a 50 microM concentration. A less pronounced increase was induced by diazepam and by the partial agonist ZK 91296. Scatchard plot analysis revealed that the effect of ZK 93423 was due to an increase in the total number of high- and low-affinity GABA binding sites. The action of ZK 93423 was mediated by benzodiazepine recognition sites since it was blocked by the benzodiazepine antagonists Ro 15-1788 and ZK 93426 at concentrations that failed to modify [3H]GABA binding on their own. Moreover the stimulatory effect of ZK 93423 on [3H]GABA binding was also blocked by the beta-carboline inverse agonist ethyl beta-carboline-3-carboxylate. These results are consistent with the view that ZK 93423 and ZK 91296, similarly to benzodiazepines, exert their pharmacological effects by enhancing the GABAergic transmission at the level of the GABA/benzodiazepine receptor complex.     

Duck skeletal muscle acylphosphatase: Primary structure

The complete amino acid sequence of duck skeletal muscle acylphosphatase is presented. The sequence was studied by the manual Edman degradation of the complete series of tryptic peptides and the amino acid composition of peptic peptides. The NH₂-terminus is acetylated, and the polypeptide consists of 102 amino acid residues. The sequence is compared with other known acylphosphatases from the skeletal muscle of several vertebrate species.     

Complete nucleotide mtDNA sequence of Barbary sheep (Ammotragus lervia).

In this report we describe the complete sequence of the mtDNA genome of Ammotragus lervia (Barbary sheep or aoudad) as obtained by PCR and sequencing with primer walking using flanking sequences. The molecule is 16,530 base pairs in length, resulting similar to those of goat and sheep. The genome organization matches to those of other mammalian mitochondrial genomes. The phylogenetic position of the Ammotragus relative to twelve other mammalian species was assessed based on protein-coding sequences. A goat-aoudad split of 9.9-8.9 MYBP has been estimated, whereas the divergence ancestor/caprines was dated at 12.1-10.8 MYBP.