University of Jena

About: University of Jena is a education organization based out in Jena, Thüringen, Germany. It is known for research contribution in the topics: Laser & Population. The organization has 22198 authors who have published 45159 publications receiving 1401514 citations. The organization is also known as: Friedrich-Schiller-Universität Jena & Friedrich Schiller University Jena.

Chemical cues, defence metabolites and the shaping of pelagic interspecific interactions

Abstract: Several observations and model calculations suggest that chemically mediated interactions can structure planktonic food webs. However, only recently have improvements in chemical methods, coupled with ecological assays, led to the characterization of chemical cues that affect the behaviour and/or physiology of planktonic organisms. We are currently beginning to elucidate if or how chemical signals can directly affect the interactions between species and even shape complex community structures in aquatic systems. Here, we highlight recent research on the nature and action of chemical signals in the pelagic marine and freshwater environments, with an emphasis on kairomones and defence metabolites.

Low-Grade Myofibroblastic Sarcoma: Analysis of 18 Cases in the Spectrum of Myofibroblastic Tumors

Abstract: The clinicopathologic, immunohistochemical, and ultrastructural features of a seemingly distinctive low-grade spindle cell sarcoma showing myofibroblastic differentiation have been analyzed in a series of 18 patients. The age range of the patients (7 women and 11 men) was 19-72 years (median: 42 years). A painless, enlarging mass was the most common clinical presentation. Five tumors arose in the oral cavity (including four lesions in the tongue), four in the lower extremities and three in the upper extremities, four cases in the abdominal/pelvic cavity, and two on the trunk. Eight soft-tissue cases involved skeletal muscle, three cases were located in perifascial tissues, and two arose in subcutaneous tissue. Tumor size ranged from 1.4 to 17 cm (median: 4 cm); in six cases (of which four were abdominal/pelvic) the lesion was larger than 5 cm. All patients were treated surgically, and four received additional adjunctive therapy. Histologically, most cases were cellular lesions showing a diffusely infiltrative pattern, and were composed of spindle-shaped tumor cells arranged mainly in fascicles. Tumor cells had poorly defined, palely eosinophilic cytoplasm and fusiform nuclei, which were either tapering and wavy or plumper and vesicular with indentations and small inconspicuous nucleoli. Tumor cells were set in a collagenous matrix often with prominent hyalinization. Mild nuclear atypia was noted in 16 cases; in the other 2 cases, and in the metastases of one other lesion, a greater degree of nuclear atypia was seen. In all but one case, the mitotic rate ranged from 1 to 6 mitoses in 10 HPFs (mean: 2/10 HPFs); in a single case, there were more than 20 mitoses in 10 HPFs. Immunohistochemically, all cases stained positively for at least one myogenic marker; 12 cases were positive for desmin, 11 for alpha-smooth muscle actin, and 6 for muscle actin (HHF35). Seven neoplasms were desmin positive/ alpha-smooth-muscle actin negative, and five cases were desmin negative/alpha-smooth-muscle actin positive emphasizing the variable immunophenotype of myofibroblastic lesions. In addition, 7 of 10 tumors stained at least focally positive for fibronectin. Ultrastructural examination in five cases showed characteristic features of myofibroblasts. Follow-up in 11 patients (median: 29 months) revealed local recurrence in 2 cases, and multiple distant soft-tissue, intraosseous, and pulmonary metastases in one other patient. Low-grade myofibroblastic sarcoma seems to represent a distinct entity in the spectrum of low-grade myofibroblastic neoplasms and is distinguishable from fibromatosis, myofibromatosis, solitary fibrous tumor, fibrosarcoma, and leiomyosarcoma.

Functional Polymers Based on Dextran

Abstract: Dextran, comprising a family of neutral polysaccharides consisting of an α-(1 → 6) linked d-glucose main chain with varying proportions of linkages and branches, depending on the bacteria used, is an interesting starting material for chemical modification reactions for the design of new functional polymers with promising properties. The review summarises recent results on structure characterisation of dextran including some comments on biosynthesis of this important class of biopolymers. Applications of dextran are discussed as well. Chemical modification reactions of dextran are increasingly studied for the structure and hence property design. The review highlights recent progress in esterification of dextran, both inorganic and organic polysaccharide esters, etherification reactions towards ionic and non-ionic ethers, and the huge variety of different conversions mainly developed for the binding of drugs. It summarises recent developments in the application of dextran derivatives with a focus on the chemical structures behind these materials such as prodrugs, bioactivity of inorganic dextran esters, heparin sulfate mimics, hydrogels, nanoparticles and self assembly structures for surface modification.