Zur gegenwärtigen problematik der evolutionsforschung

Reflections on the actual problematics of the palaeontological evolution research are observed under epistemological aspects. When discussing new or only pretended new beginnings, sometimes with claim to neutral-point elucidations, success and merit of the traditional methods in palaeontology should not be forgotten. Gradualism and punctualism reduce the multilateral reality of nature.     

Ammoniteli der GattungParapatoceras aus dem Oberen Mitteljura des Süntels (östliches Wesergebirge,Niedersachsen)

The Parapatocerates from the Süntel (Weser mountains, Northwest Germany) are described being an utmost variable subspecies respectively geographical raceParapatoceras distans (?) bentzi (Potonié) with two possibly modificatorily separated form groups. They differ from the similarP. distans(?) crioconus (Buckman) (=Crioconites Buckman) of Chippenham (England) in primary quadrilobaty and further characteristics accessible only by precise analysis. To establish the speciesdistans Baugier & Sauzé and with this the genusParapatoceras, recovery of the holotype or a determination of a neotype is required. A very similar but probably quinquelobate specimen (Parapatoceras sp.) from the Macrocephalus oolite of Hanover seems to accentuate once more the taxonomically minor degree of the quadri- or quinquelobaty inParapatoceras.     

Latest Advances on Bacterial Cellulose‐Based Materials for Wound Healing,Delivery Systems,and Tissue Engineering

Bacterial cellulose (BC) is a nanocellulose form produced by some nonpathogenic bacteria. BC presents unique physical, chemical, and biological properties that make it a very versatile material and has found application in several fields, namely in food industry, cosmetics, and biomedicine. This review overviews the latest state‐of‐the‐art usage of BC on three important areas of the biomedical field, namely delivery systems, wound dressing and healing materials, and tissue engineering for regenerative medicine. BC will be reviewed as a promising biopolymer for the design and development of innovative materials for the mentioned applications. Overall, BC is shown to be an effective and versatile carrier for delivery systems, a safe and multicustomizable patch or graft for wound dressing and healing applications, and a material that can be further tuned to better adjust for each tissue engineering application, by using different methods.     

Discrepancies in HLA typing by PCR-SSOP and SBT techniques: a case study

Six hundred twenty-one samples from Portugal, the Cabo Verde archipelago, and Guinea-Bissau were typed for HLA-A, HLA-B, and HLA-DRB1 using the polymerase chain reaction-sequence-specific oligonucleotide probe (PCR-SSOP) method and the sequence-based typing (SBT) method to characterize and compare discrepancies between the two methods. Fifty-three alleles (4.27% of 1242 chromosomes typed) identified by the PCR-SSOP method were not concordant with the results obtained using the SBT method. Thirty-four (2.74% of total chromosomes typed) PCR-SSOP mistyping results were discrepancies inside the same allele group and 19 others (1.53% of total chromosomes typed) were relative to nonconcordant results between different groups. PCR-SSOP allele mistyping is the result of interpretation difficulties resulting from less intense, absent, or dubious hybridization patterns. Noncommercial PCR-SSOP procedures are highly exigent on the technicians' experience and the availability of properly calibrated high-precision equipment.     

Uncommon acquired Gerbode defect following extensive bicuspid aortic valve endocarditis

Gerbode defect is a rare type of left ventricle to right atrium shunt. It is usually congenital in origin, but acquired cases are also described, mainly following infective endocarditis, valve replacement, trauma or acute myocardial infarction. We report a case of a 50-year-old man who suffered an extensive and complex infective endocarditis involving a bicuspid aortic valve, the mitral-aortic intervalvular fibrosa and the anterior leaflet of the mitral valve. After dual valve replacement and annular reconstruction, a shunt between the left ventricle and the right atrium - Gerbode defect, and a severe leak of the mitral prosthesis were detected. Reintervention was performed with successful shunt closure with an autologous pericardial patch and paravalvular leak correction. No major complications occurred denying the immediate post-surgery period and the follow-up at the first year was uneventful.     

Land‐atmosphere exchange of methane from soil thawing to soil freezing in a high‐Arctic wet tundra ecosystem

The land‐atmosphere exchange of methane (CH₄) and carbon dioxide (CO₂) in a high‐Arctic wet tundra ecosystem (Rylekærene) in Zackenberg, north‐eastern Greenland, was studied over the full growing season and until early winter in 2008 and from before snow melt until early winter in 2009. The eddy covariance technique was used to estimate CO₂ fluxes and a combination of the gradient and eddy covariance methods was used to estimate CH₄ fluxes. Small CH₄ bursts were observed during spring thawing 2009, but these existed during short periods and would not have any significant effect on the annual budget. Growing season CH₄ fluxes were well correlated with soil temperature, gross primary production, and active layer thickness. The CH₄ fluxes remained low during the entire autumn, and until early winter. No increase in CH₄ fluxes were seen as the soil started to freeze. However, in autumn 2008 there were two CH₄ burst events that were highly correlated with atmospheric turbulence. They were likely associated with the release of stored CH₄ from soil and vegetation cavities. Over the measurement period, 7.6 and 6.5 g C m^?2 was emitted as CH₄ in 2008 and in 2009, respectively. Rylekærene acted as a C source during the warmer and wetter measurement period 2008, whereas it was a C sink for the colder and drier period of 2009. Wet tundra ecosystems, such as Rylekærene may thus play a more significant role for the climate in the future, as temperature and precipitation are predicted to increase in the high‐Arctic.