A liquid chromatographic–tandem mass spectrometric (HPLC-MS/MS) method is proposed for the identification and quantification of tylosin in honey. Sample treatment involves an extraction in a Tris ...buffer at pH 10.5, followed by a solid-phase clean up step on an Oasis HLB column. Roxithromycin was used as the internal standard. Chromatographic separation of tylosin and roxithromycin was performed on an XTerra MS C
18 column (100
mm × 2.1
mm i.d., 5
μm) using a gradient of aqueous 0.01
M ammonium acetate pH 3.5 and acetonitrile as the mobile phase, at a flow rate of 0.25
ml
min
−1. The method was validated according to the guidelines laid down by the Commission Decision 2002/657/EC. Tylosin residues were confirmed by MS/MS experiments considering the appropriate identification points. All validation parameters such as Ccα (lower than 3
ng
g
−1), Ccβ (lower than 5
ng
g
−1), recovery and precision were assessed on the basis of the “critical ion” (less intense ion permitting unambiguous identification of the analyte).
We report on a patient with a femoropopliteal bypass infected by Kytococcus sedentarius. Treatment consisted of resection of the infected prosthesis with homograft substitution and antibiotic therapy ...started postoperatively. At 6 months followup, the patient showed no signs of infection and results of laboratory findings were normal.
Hybrid organic–inorganic materials exhibit so versatile properties that they can be considered one of the most interesting classes of materials for photonic applications, for the development of both ...passive and active devices. A synthetic route used for the preparation of nanostructured organic/inorganic (O/I) materials is the assembling of nano-building blocks (NBBs). This approach allows controlling the extent of phase interaction, which in its turn governs the structure-properties relationships. The non-hydrolytic sol–gel process is recognized as a useful route for the preparation of nanostructured molecular units. The condensation reaction of methacryloxypropyl trimethoxysilane and diphenylsilanediol in a non-hydrolytic sol–gel process has been exploited in order to synthesize nanostructured molecular units for the preparation of hybrid organic/inorganic coatings. The non-hydrolytic condensation reactions were run adding different compounds such as triethylamine, titanium isopropoxide, titanium chloride, and dibutyldilauryltin as condensation promoters. The NBB synthesis was also run under controlled hydrolitic conditions, by exploiting the in situ water production using an ethanol/acetic acid mixture. These reactions have been compared in terms of the influence of the employed reagents on the condensation degree and the product structure. Multinuclear NMR, ATR-FTIR and FT-Raman techniques have been used to study the reaction steps and characterize the final condensation products. Hybrid O/I materials have been prepared by assembling methacrylate-based NBBs in the presence of suitable thermal and photo-initiators. The study on the progress of the thermal polymerization process using differential scanning calorimetry (DSC) will be presented, as well as the preliminary results on the two photon polymerization (TPP) process for the preparation of patternable films.
This paper describes the scientific aims and potentials as well as the preliminary technical design of IRIDE, an innovative tool for multi-disciplinary investigations in a wide field of scientific, ...technological and industrial applications. IRIDE will be a high intensity “particles factory”, based on a combination of high duty cycle radio-frequency superconducting electron linacs and of high energy lasers. Conceived to provide unique research possibilities for particle physics, for condensed matter physics, chemistry and material science, for structural biology and industrial applications, IRIDE will open completely new research possibilities and advance our knowledge in many branches of science and technology. IRIDE is also supposed to be realized in subsequent stages of development depending on the assigned priorities.
Small angle x-ray scattering has been used to monitor calpain structural transitions during the activation process triggered
by Ca 2+ binding. The scattering pattern of the unliganded enzyme in ...solution does not display any significant difference with that
calculated from the crystal structure. The addition of Ca 2+ promotes the formation of large aggregates, indicating the exposure of hydrophobic patches on the surface of the protease.
In contrast, Ca 2+ addition in the presence of the thiol proteinase inhibitor E64 or of the inhibitor leupeptin causes a small conformational
change with no dissociation of the heterodimer. The resulting conformation appears to be slightly more extended than the unliganded
form. From the comparison between ab initio models derived from our data with the crystal structure, the major observable conformational change appears to be localized
at level of the L-subunit and in particular seems to confirm the mutual movement already observed by the crystallographic
analysis of the dII (dIIb) and the dI (dIIa) domains creating a functional active site. This work not only provides another
piece of supporting evidence for the calpain conformational change in the presence of Ca 2+ , but actually constitutes the first experimental observation of this change for intact heterodimeric calpain in solution.
Carotenoid-binding proteins of photosystem II BASSI, Roberto; PINEAU, Bernard; DAINESE, Paola ...
European journal of biochemistry,
March 1993, Volume:
212, Issue:
2
Journal Article
Peer reviewed
Open access
The distribution of the photosynthetic pigments of the chlorophyll-binding proteins or photosystem-II membranes, isolated from dark-adapted maize leaves was determined. Most (80%) of a xanthophyll, ...violaxanthin, was found in the three minor chlorophyll-a/b proteins CP24, CP26 and CP29 whose function is unknown. Violaxanthin is the precursor of zeaxanthin, which is involved in dissipating excess excitation energy into heat Demmig-Adams, B. (1991) Biochim. Biophys. Acta 1020, 1-24 under conditions of high transmembrane pH gradient Gilmore, A. M. and Yamamoto, H. Y. (1992) Proc. Natl Acad Sci. USA 89, 1899-1903. We propose that a role for the minor photosystem-II chlorophyll-a/b proteins is the regulation of energy transfer to the reaction centre. It was also confirmed that the photosystem II reaction centre (D1-D2-cytochrome b559) contains beta-carotene as the only carotenoid. However, the two other chlorophyll-a-binding proteins of photosystem II, CP47 and CP43, bind not only beta-carotene, but also the xanthophyll lutein, previously thought to be restricted to chlorophyll-a/b proteins.
The resistance of maize plants to cold stress has been associated with the appearance of a new chlorophyll a/b binding protein in the thylakoid membrane following chilling treatment in the light. The ...cold-induced protein has been isolated, characterized by amino acid sequencing, and pulse labeled with radioactive precursors, showing that it is the product of post-translational modification by phosphorylation of the minor chlorophyll a/b protein CP29 rather than the product of a cold-regulated gene or an unprocessed CP29 precursor. We show here that the CP29 kinase activity displays unique characteristics differing from previously described thylakoid kinases and is regulated by the redox state of a quinonic site. Finally, we show that maize plants unable to perform phosphorylation have enhanced sensitivity to cold-induced photoinhibition.
The effects of low temperature on the relative contributions of the reaction center and the antenna activities to photosystem II (PSII) electron transport were estimated by chlorophyll fluorescence. ...The inhibition of PSII photochemistry resulted from photo-damage to the reaction center and/or a reduced probability of excitation energy trapping by the reaction center. Although chill treatment did not modify the proportion of the dimeric to monomeric PSII, it destabilized its main light-harvesting complex. Full protection of the reaction center was achieved only in the presence of the phosphorylated PSII subunit, CP29. In a nonphosphorylating genotype the chill treatment led to photoinhibitory damage. The phosphorylation of CP29 modified neither its binding to the PSII core nor its pigment content. Phosphorylated CP29 was isolated by flat-bed isoelectric focusing. Its spectral characteristics indicated a depletion of the chlorophyll spectral forms with the highest excitation transfer efficiency to the reaction center. It is suggested that phosphorylated CP29 performs its regulatory function by an yet undescribed mechanism based on a shift of the equilibrium for the excitation energy toward the antenna.
This study was undertaken to evaluate predictors and outcomes of octogenarians who underwent abdominal aortic aneurysm repair.
A prospective observational study.
Between January 1st, 1997 and April ...15th, 2005, 31 octogenarians were admitted to our Department with the diagnosis of abdominal aortic aneurysm. Mean follow-up time was 53.7±27.2 months. All patients were in good clinical condition and represented a selected healthy group of octogenarians.
The overall perioperative (30-days) mortality rate was 3.1%. The total in-hospital morbidity rate was 22.6%. Overall survival estimates at 48 and 96 months were 81±8% and 46±21%, respectively. The actuarial freedom from aneurysm-related death at 48 and 96 months was 96±4% and 96±4%, respectively. The actuarial freedom from aneurysm-unrelated death at 48 and 96 months was 84±7% and 48±21%. Only coronary artery disease was a significant predictor of survival using multivariate stepwise logistic regression analysis.
In this series, AAA surgery was carried out in selected octogenarians without affecting long-term survival.
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