Lagrangian interactions within a special class of covariant mixed-symmetry type tensor gauge fields

Consistent nontrivial interactions within a special class of covariant mixed-symmetry type tensor gauge fields of degree three are constructed from the deformation of the solution to the master equation combined with specific cohomological techniques. In spacetime dimensions strictly greater than four, the only consistent interaction terms are those gauge invariant under the original symmetry. Only in four spacetime dimensions the gauge symmetry is found deformed.Comment: 24 pages; two equations corrected; matches the published versio

Imaging of atomic orbitals with the Atomic Force Microscope - experiments and simulations

Atomic force microscopy (AFM) is a mechanical profiling technique that allows to image surfaces with atomic resolution. Recent progress in reducing the noise of this technique has led to a resolution level where previously undetectable symmetries of the images of single atoms are observed. These symmetries are related to the nature of the interatomic forces. The Si(111)-(7x7) surface is studied by AFM with various tips and AFM images are simulated with chemical and electrostatic model forces. The calculation of images from the tip-sample forces is explained in detail and the implications of the imaging parameters are discussed. Because the structure of the Si(111)-(7x7) surface is known very well, the shape of the adatom images is used to determine the tip structure. The observability of atomic orbitals by AFM and scanning tunneling microscopy is discussed.Comment: 21 pages, 17 figure

Particularities of tissue regeneration of decellularized bovine pericardium xenografts used in the reconstruction of the anterior abdominal wall defects in the experimental model

The purpose of this study was to evaluate the regeneration potential of decellularized bovine pericardium grafts used as an option to close the abdominal wall defects in the experimental model. The study group consisted of pigs subjected to reconstructive surgery of congenital abdominal wall defects (group 1 - 3 animals) (fig. 1) and total defect of the abdominal wall created surgically (involving all layers, including the peritoneum) with decellularized bovine pericardium (group 2 - 3 animals). Animals were sacrificed and investigated 30 days (3 animals) and 90 days after surgery (3 animals). he results of this experimental study have allowed us to conclude the following: - The acellular bovine pericardium graft is characterized by strength and durability, favorable for the reconstruction of major abdominal wall defects. - In the regenerative-reparative processes of the acellular bovine pericardium grafts used in the reconstruction of the abdominal wall defects together with fibrogenesis processes, there are also processes of metaplasia with differentiation in chondroblasts which induce the neoformation of cartilage foci in the biological implant, which, then functions as an enchondral ossification factor with the formation of trabecular osteogenesis and ossification foci. - The results obtained imply the need for further studies to clarify the role of these changes in the development of potential follow-up postoperative complications

In vivo evaluation of xenogeneic acellular bovine fascia grafts in the reconstruction of abdominal wall defects in swine experimental model

Public Institution State University of Medicine and Pharmacy “Nicolae Testemiţanu”, PMSI Mother and Child Institute, Chisinau, Republic of MoldovaABSTRACT In this study autor purpose to evaluate the feasibility of using bovine fascia in the experimental substitution of the fascial plan for the reconstruction of major anterior abdominal wall defects in the experimental model. Plastic reconstruction of the surgically induced abdominal wall defect using decellularized bovine fascia grafts was performed on 5-week-old Landrace pigs (3 animals) in which the abdominal wall defect of 10x5.0 cm was surgically induced with the involvement of all layers, including the peritoneum. The animals were subsequently euthanized 90 days after the intervention. For decellularization, sterile 0.5% SDS solution (HiMedia) was used in volume required to obtain acellular tissues. The solution was changed every 24 hours for 72 hours. The preventive results of the histopathological examination allowed the author to conclude that the use of decellularized bovine fascia grafts in the experimental model is characterized by the dominance of active regenerative processes with tissue remodeling and host cell invasion, the xenogeneic implant tissues being subjected to gradual degradation and substituted with the neoformed host connective tissue, the rationale of the usefulness of this biological material requiring additional comparative and clinical immunological studies. The results of this experimental study allow us to conclude the following that the usage of bovine fascia acellular grafts as an alternative xenogeneic biological implant in reconstructive surgery of abdominal wall defects, this option requiring additional comparative and clinical immunological studies

Assessment of morpho-pathological changes of placental complexes in newborns with gastroschisis

Universitatea de Stat de Medicină şi Farmacie Nicolae Testemiţanu, IMSP Institutul Mamei şi CopiluluiScopul acestui studiu a fost evaluarea modificărilor morfopatologice ale complexelor placentare în caz de gastroschisis. Material şi metode. Lucrarea include analiza retrospectivă a modificărilor morfopatologice ale complexelor placentare înregistrate în 10 cazuri de gastroschisis. Rezultate şi discuţii. La examenul macroscopic al complexelor placentare a fost constatată prezenţa malformaţiilor de formă (2 cazuri), reprezentate de placentă bilobată şi placentă cu lob suplimentar, şi a anomaliilor de inserţie a cordonului ombilical (7 cazuri), inclusiv: inserţie marginală (3 cazuri), inserţie velamentoasă (2 cazuri), inserţie periferică (2 cazuri). Investigaţiile histomorfologice au relevat în 4 cazuri o amnionită subacută meconiofagică corioamnională şi parietală, inclusiv în zona deciduală parietală, acest fapt confirmând hipoxemia intrauterină cronică a fătului. În 2 cazuri a fost constatată implicarea în procesul infecţios a vaselor ombilicale afectate de endofl ebită şi endoarterită, ultima elucidând prezenţa infecţiei intrauterine la făt. În unele zone ale placentei, au fost atestate leziuni reziduale ale reţelei vasculare, precum calcificări focale la nivelul venelor ombilicale, prezenţa trombilor calcificaţi în reţeaua vasculară a vilozităţilor coriale cu o viluizită productivă cu focare moderate. La examinarea corionului velar (9 cazuri) au fost observate grupuri de vilozităţi afuncţionale cu particularităţi morfologice corespunzătoare perioadelor precoce de gestaţie - 6-12 săptămâni. Concluzie. Rezultatele prealabile ale studiului ne permit să conchidem că gastroschisisul este consecinţa unor perturbări survenite în ontogeneză la etapa fetală, inclusiv a malformaţiilor complexului placentar dezvoltate ca rezultat al unor condiţii nefavorabile de implantare şi diferenţiere feto-placentară şi embrionară. Astfel, în opinia noastră, gastroschisisul reprezintă o blastopatie cu un efect clinic întârziat.The purpose of this study was to evaluate morpho-pathological changes of placental complexes in gastroschisis. Materials and methods. The paper includes a retrospective analysis of morpho-pathological changes of placental complex recorded in 10 cases of gastroschisis. Results and discussions. The microscopic examination of placental complexes found the presence of malformations of shape (2 cases), represented by the bilobed placenta and accessory placental lobe, as well as abnormalities of the umbilical cord insertion (7 cases), including marginal insertion (3 cases) velamentous insertion (2 cases), and peripheral insertion (2 cases). The histomorphological investigations revealed 4 cases of subacute meconium-phagic chorioamnionitis and parietal amnionitis, including the decidual parietal area, it confirming chronic intrauterine fetal hypoxemia. The infectious involvement of umbilical vessels was detected in 2 cases. They were affected by endophlebitis and endarteritis, the latter revealing the presence of intrauterine infection in the fetus. Some residual lesions of the vascular network were found in certain areas of the placenta, such as focal calcification at the level of the umbilical veins, the presence of calcified thrombi in the vascular network of chorionic villi with productive villositis with moderate foci. The examination of the velar chorion (9 cases) revealed groups of nonfunctional villi with morphological features corresponding to early gestation periods 6 -12 weeks. Conclusion. The preliminary results of the study allow us to conclude that gastroschisis is the consequence of some disturbances occurring in the ontogenesis at the fetal stage, including the malformations of the placental complex developed as a result of some unfavorable conditions of embryonic and fetal-placental implantation and differentiation. Thus, in our opinion, gastroschisis is a blastopathy with a delayed clinical effect

In vivo evaluation of xenogeneic acellular bovine fascia grafts in the reconstruction of abdominal wall defects in swine experimental model

In this study autor purpose to evaluate the feasibility of using bovine fascia in the experimental substitution of the fascial plan for the reconstruction of major anterior abdominal wall defects in the experimental model. Plastic reconstruction of the surgically induced abdominal wall defect using decellularized bovine fascia grafts was performed on 5-week-old Landrace pigs (3 animals) in which the abdominal wall defect of 10x5.0 cm was surgically induced with the involvement of all layers, including the peritoneum. The animals were subsequently euthanized 90 days after the intervention. For decellularization, sterile 0.5% SDS solution (HiMedia) was used in volume required to obtain acellular tissues. The solution was changed every 24 hours for 72 hours. The preventive results of the histopathological examination allowed the author to conclude that the use of decellularized bovine fascia grafts in the experimental model is characterized by the dominance of active regenerative processes with tissue remodeling and host cell invasion, the xenogeneic implant tissues being subjected to gradual degradation and substituted with the neoformed host connective tissue, the rationale of the usefulness of this biological material requiring additional comparative and clinical immunological studies. The results of this experimental study allow us to conclude the following that the usage of bovine fascia acellular grafts as an alternative xenogeneic biological implant in reconstructive surgery of abdominal wall defects, this option requiring additional comparative and clinical immunological studies

Irreducible Hamiltonian approach to the Freedman-Townsend model

The irreducible BRST symmetry for the Freedman-Townsend model is derived. The comparison with the standard reducible approach is also addressed.Comment: 18 pages, LaTeX 2.0