Search results for "plastic"
showing 10 items of 7296 documents
Macromolecules in ordered media: 4. Poly(2-vinyl pyridine)-liposome association induced by electrostatic interactions
1997
Abstract We have investigated the interaction between vesicles based on dimyristoyl phosphatidic acid (DMPA) and a polymer, such as poly(2-vinyl pyridine) (P2VPy), on the basis of both partition and binding models. The resulting association curves are non monotonous being three regions clearly evidenced. The electrostatic and steric origin of the attractive or repulsive interactions are analyzed as a function of pH, ionic strength and temperature using the fluorescence spectroscopy technique. We emphasize the importance of differentiating the ideal definition of the binding constant from the theoretically evaluated including the activity coefficient, γ, to take into account shifts from the …
Comparison of linear and hyperbranched polyether lipids for liposome shielding by 18F-radiolabeling and positron emission tomography
2018
Multifunctional and highly biocompatible polyether structures play a key role in shielding liposomes from degradation in the bloodstream, providing also multiple functional groups for further attachment of targeting moieties. In this work hyperbranched polyglycerol (hbPG) bearing lipids with long alkyl chain anchor are evaluated with respect to steric stabilization of liposomes. The branched polyether lipids possess a hydrophobic bis(hexadecyl)glycerol membrane anchor for the liposomal membrane. hbPG was chosen as a multifunctional alternative to PEG, enabling the eventual linkage of multiple targeting vectors. Different hbPG lipids (Mn = 2900 and 5200 g mol-1) were examined. A linear bis(h…
On the Adsorption Process in Polymer Brushes: A Monte Carlo Study
1996
The adsorption process of the single polymer chain in a polymer brush of varying surface coverages is studied by means of Monte Carlo simulations of the bond-fluctuation lattice model. Only the end monomers can adsorb at the grafting surface, whereas inner monomers interact repulsively with it. The brush builds up a steric hindrance which forces the penetrating polymer to stretch strongly and which is responsible for small adsorption probabilities at surface coverages close to the overlap density. The final step of the adsorption process is determined by a fluctuation of the end monomer around its average position, which is comparable to the initial step of the desorption process.
Surgical treatment of solitary sternal metastasis from breast cancer Case report
2016
Bone metastasis is a frequent and early complication of breast cancer. This case report describes a technique for a partial exeresis of the sternum and the reconstruction of the pleura with autologous dermis from the lower abdomen and the loss of substance with a myocutaneous flap.We describe the case of a 50-year old woman with a sternal excavated lesion with pathologic fracture due to an invasive adenocarcinoma, treated with a partial exeresis of the sternum and the reconstruction with a myocutaneous flap.The patient doesn't show evidence of recurrent disease and the stability of her chest well preserved.Metastatic breast cancer to the sternum, if detected early and treated aggressively, …
Intratumoral Heterogeneity for hsp90β mRNA Levels in a Breast Cancer Cell Line
1997
BC-3A and BC-61 are two breast cancer cell lines that have been cloned from parental 8701-BC cells and exhibit different biosynthetic, proliferative, and invasive properties in vitro. In the attempt to search whether alterations in the profiles of gene expression could be detected, we have submitted both cytotypes to identification of differentially expressed cDNAs. In addition, steroid hormone receptor mRNA arrays and in vivo tumorigenesis of the two lines have been checked. The technique used allowed identification of changes in the expression of the 90-kD heat shock protein-beta (hsp90beta) which is prominently down-regulated in BC-61 cells. Because we have also found that these cells, w…
Zum Wandel motorischer Einheiten bei Änderung des Aktivitätsmusters durch elektrische Reizung - Elektrostimulation und ihre klinischen Einsatzmöglich…
1989
Motoneuron and muscle fibers interact on the motor unit level, whereby discharge characteristics from the neuron imposed on the muscle seem to play a major role. Within the unit all muscle fibers are biochemically homogeneous and display a high degree of plasticity under different functional demands. To distinguish the existing different units rationals are listed that classify the units by physiological and histochemical parameters. Furthermore the review summarizes the available knowledge on the importance of activity patterns--as a biological principle--involved in the control of phenotypic expression of innervated and denervated muscle. The sequelae are shown of electrical stimulation o…
A simplified analysis for the evaluation of stochastic response of elasto-plastic oscillators
1999
Abstract The paper deals with dynamic hysteretic oscillators without post-yielding hardening, called ideal elasto-plastic oscillators, subjected to white noise. They are characterized by the fact that they do not reach stationarity even though excited by stationary stochastic processes. A simplified solution procedure to capture this behaviour is presented in this paper. It is based on modelling the accumulated plastic deformations as a homogeneous compound Poisson process. In particular, two aspects are addressed in the paper: (1) evaluation of the probabilistic parameters of the accumulated plastic deformation process; and (2) evaluation of the second-order cumulants of the response by me…
Oral microbiome and systemic antineoplastics in cancer treatment:a systematic review
2021
Oral mucositis is one of the most common side effects in cancer patients receiving systemic antineoplastics. However, the underlying biological mechanisms leading to this condition are still unclear. For this reason, it has been hypothesised that systemic antineoplastics may cause an imbalance on the oral microbiota that subsequently triggers oral mucosa damage. A systematic review was performed following the PRISMA protocol and the PICO question established was: patients diagnosed with cancer, who are candidates for receiving systemic antineoplastics (P=Patients), that undergo oral microbiome determinations (I=Intervention), before and after systemic antineoplastics administration (C=Compa…
Experimental Tests of Fatigue Induced Delamination in Gfrp and Cfrp Laminates
2007
This work deals with the experimental analysis of the delamination phenomena in various composite materials under different loading conditions. Quasi-static and fatigue tests are performed on specimens made of glass-fibre reinforced plastic (GFRP) and carbon-fibre reinforced plastic (CFRP). In particular, under both quasi-static and fatigue loading, single fracture modes I and II (using standard DCB and ENF test configurations) and mixed modes I+II (using the MMB test configuration) with several mode mixtures, have been analysed. Further experiments of delamination growth with mode mixture that varies with the crack length, will be performed.