Chitin-based scaffolds are an integral part of the skeleton of the marine demosponge Ianthella basta.

The skeletons of demosponges, such as Ianthella basta, are known to be a composite material containing organic constituents. Here, we show that a filigree chitin-based scaffold is an integral component of the I. basta skeleton. These chitin-based scaffolds can be isolated from the sponge skeletons using an isolation and purification technique based on treatment with alkaline solutions. Solid-state (13)C NMR, Raman, and FT-IR spectroscopies, as well as chitinase digestion, reveal that the isolated material indeed consists of chitin. The morphology of the scaffolds has been determined by light and electron microscopy. It consists of cross-linked chitin fibers approximately 40-100 nm in diameter forming a micro-structured network. The overall shape of this network closely resembles the shape of the integer sponge skeleton. Solid-state (13)C NMR spectroscopy was used to characterize the sponge skeleton on a molecular level. The (13)C NMR signals of the chitin-based scaffolds are relatively broad, indicating a high amount of disordered chitin, possibly in the form of surface-exposed molecules. X-ray diffraction confirms that the scaffolds isolated from I. basta consist of partially disordered and loosely packed chitin with large surfaces. The spectroscopic signature of these chitin-based scaffolds is closer to that of alpha-chitin than beta-chitin.

Three-dimensional chitin-based scaffolds from Verongida sponges (Demospongiae: Porifera). Part II: Biomimetic potential and applications.

In order to evaluate the biomedical potential of three-dimensional chitinous scaffolds of poriferan origin, chondrocyte culturing experiments were performed. It was shown for the first time that freshly isolated chondrocytes attached well to the chitin scaffold and synthesized an extracellular matrix similar to that found in other cartilage tissue engineering constructs. Chitin scaffolds also supported deposition of a proteoglycan-rich extracellular matrix of chondrocytes seeded bioconstructs in an in vivo environment. We suggest that chitin sponge scaffolds, apart from the demonstrated biomedical applications, are highly optimized structures for use as filtering systems, templates for biomineralization as well as metallization in order to produce catalysts.

Three-dimensional chitin-based scaffolds from Verongida sponges (Demospongiae: Porifera). Part I. Isolation and identification of chitin.

Marine invertebrate organisms including sponges (Porifera) not only provide an abundant source of biologically active secondary metabolites but also inspire investigations to develop biomimetic composites, scaffolds and templates for practical use in materials science, biomedicine and tissue engineering. Here, we presented a detailed study of the structural and physico-chemical properties of three-dimensional skeletal scaffolds of the marine sponges Aiolochroia crassa, Aplysina aerophoba, A. cauliformis, A. cavernicola, and A. fulva (Verongida: Demospongiae). We show that these fibrous scaffolds have a multilayered design and are made of chitin. (13)C solid-state NMR spectroscopy, NEXAFS, and IR spectroscopy as well as chitinase digestion and test were applied in order to unequivocally prove the existence of alpha-chitin in all investigated species.

Solid-state nuclear magnetic resonance investigations on chlorocyclophosphazenes.

The present study deals with solid-state nuclear magnetic resonance (NMR) investigations on hexachlorocyclotriphosphazene (N3P3Cl6) and T and K form of octachlorocyclotetraphosphazene (N4P4Cl8). Using 31P NMR we have recorded spectra of different magic-angle spinning (MAS) frequencies and static powder spectra. By means of the analysis of spinning sideband intensities the isotropic chemical shifts and the principal values of the chemical shift tensor could be determined. Because of the interactions between phosphorus and the neighbouring chlorine nuclei in the MAS spectra of N3P3Cl6 and N4P4Cl8 more lines were found to exist than was expected with regard to the isotropic chemical shift values according to the crystallographic phosphorus positions. To support this evidence solid-state spectra of the geminally disubstituted compound 2,2,4,4-tetrachloro-6,6-bisthiophenylcyclotriphosphazene [N3P3Cl4(SPh)2] were used. In addition, by means of the individual gauched localized orbitals (IGLO) method 31P NMR chemical shifts, principal values and the orientation of the principal axes of the shielding tensor were calculated for the chlorocyclophosphazenes.

[Plague in Central Germany in the 17th century]. / Die Pest in Mitteldeutschland im 17, Jahrhundert.

It is reported on the experiences from several events of epidemic plague in the 17th century, above all in Middle Germany. Documentary material and the historic literature belonging to this served as basis. The mortality rates of plague are discussed, which proved as relatively different. The seasonal courses of the individual epidemics are discussed, which took place above all in the months July, August and September and finished in winter, what is connected with the biology of the flea. It is emphasized that the mortality of children is particularly in the plague, whereas the women and above all the men somewhat less frequently die of the epidemic, unless statistically significant differences are the result in these cases. The inter-familiar infection chains proved as relatively long so that in these cases multiple infections and secondary diseases are supposed to be the cause. It seems to be very likely that for the events of plague in Europe not the infection formula rat - plague-flea - man is valid, but the infection took place interhumanly according to the formula man - Pulex irritans - man.

[Ciaglia percutaneous dilatation tracheotomy with endoscopic control. Analysis of complication-fraught steps]. / Die perkutane Dilatationstracheotomie nach Ciaglia unter endoskopischer Kontrolle. Analyse von komplikationsträchtigen Schritten.

Since the first description by Ciaglia in 1985, percutaneous dilatational tracheostomy (PDT) has emerged worldwide to be a favored and frequently used technique for airway control. Advantages are the rapidity, simplicity and independence of the physician. These characteristics tempt clinicians to perform the procedure uncritically and thus produce complications. Based on our experiences with the technique and on a critical analysis of the literature the indications and optimal operative technique are discussed. Operative steps are illustrated and potential pitfalls (anatomic variations, injury to vital structures and bleeding) are defined. In our experience endoscopic control plays a crucial role in preventing intraoperative complications. ENT colleagues should know the technique because of their experience with tracheotomized patients and should offer their services to other disciplines.

Residual 31P, 35,37Cl dipolar coupling in 31P MAS spectra of chlorocyclophosphazenes.

In 31P MAS NMR spectra of chlorocyclophosphazenes, characteristic splittings have been observed for PCI or PCl2 groups. At different applied magnetic fields, the fine structure and total width of the patterns change in a characteristic way, demonstrating that the splittings are due to indirect spin-spin and residual dipolar interactions with the chlorine nuclei directly bonded to phosphorus. For trans-nongeminal N3P3Cl3(NMe2)3 and N3P3Cl6 as examples, the spectra have been analyzed to obtain information on chlorine nuclear quadrupole coupling constants and 35,37Cl, 3P indirect spin-spin coupling constants. Neglect of these interactions may result in misinterpretations of the multiplicity in 3P MAS spectra of chlorophosphazenes.

Comparative study of visual, auditory, and olfactory function in Usher syndrome.

BACKGROUND: Usher syndrome is a genotypically and phenotypically heterogeneous group of autosomal recessive diseases featuring retinitis pigmentosa (RP) and sensorineural hearing loss. A general ciliary dysfunction has been suspected following reports of a mutated cytoskeletal protein (myosin VIIA) in type IB, and preliminary data has suggested an olfactory deficit. The purpose of this study was to quantitatively assess olfactory function in Usher syndrome patients and to search for a correlation between the degree of impairment of the three sensory systems as indication of an underlying ciliary defect. METHODS: 39 patients with Usher syndrome (8 type I, 31 type II) were examined. The ophthalmologic protocol included patient history, visual acuity, eye morphology, Goldmann perimetry, and electroretinography. The ENT protocol included a thorough examination, speech-recognition test, pure-tone audiometry and an olfactory function test. RESULTS: In both groups, visual acuity was typically 20/40, the remaining visual field area was small, and the ERG responses were low to non-detectable. Average hearing loss was 100% in type I and 40% in type II. Olfactory thresholds were normal [median 9.7 (I) and 8.5 (II) vs. 8.5 in the control group]. There were multiple significant correlations between parameters of the same organ, but no relationship between parameters of different sensory systems. CONCLUSION: Almost all Usher syndrome patients in this study had an advanced form of RP. In contrast, auditory function differed considerably between type I and type II. An impairment of the olfactory system could not be detected, and there was no correlation between parameters representing visual function, hearing ability, and olfactory sense.

Internet-assisted exercises in structural analysis.

In this report we describe our experience in the analytical chemistry curriculum of teaching spectrometer principles and preparing spectroscopy laboratory exercises by means of virtual instruments. The benefits of the intensified preparation of laboratory exercises by virtual instruments will be evaluated with respect to the subsequent handling of real instruments. The utilization of in-house electronic media with Internet resources for elucidation and verification of a structural assignment will also be considered.