Effects of leaf water evaporative 2 H-enrichment and biosynthetic fractionation on leaf wax n-alkane δ2 H values in C3 and C4 grasses.

Leaf wax n-alkane δ2 H values carry important information about environmental and ecophysiological processes in plants. However, the physiological and biochemical drivers that shape leaf wax n-alkane δ2 H values are not completely understood. It is particularly unclear why n-alkanes in grasses are typically 2 H-depleted compared with plants from other taxonomic groups such as dicotyledonous plants and why C3 grasses are 2 H-depleted compared with C4 grasses. To resolve these uncertainties, we quantified the effects of leaf water evaporative 2 H-enrichment and biosynthetic hydrogen isotope fractionation on n-alkane δ2 H values for a range of C3 and C4 grasses grown in climate-controlled chambers. We found that only a fraction of leaf water evaporative 2 H-enrichment is imprinted on the leaf wax n-alkane δ2 H values in grasses. This is interesting, as previous studies have shown in dicotyledonous plants a nearly complete transfer of this 2 H-enrichment to the n-alkane δ2 H values. We thus infer that the typically observed 2 H-depletion of n-alkanes in grasses (as opposed to dicots) is because only a fraction of the leaf water evaporative 2 H-enrichment is imprinted on the δ2 H values. Our experiments also show that differences in n-alkane δ2 H values between C3 and C4 grasses are largely the result of systematic differences in biosynthetic fractionation between these two plant groups, which was on average -198‰ and-159‰ for C3 and C4 grasses, respectively.

[Fractures of the neck of the femur in younger patients (15-50 years old). Outcome 4 years after surgery]. / Die Schenkelhalsfraktur bei jüngeren Patienten (15-50 Jahre). Klinisch-radiografisches Outcome 4 Jahre nach operativer Therapie.

INTRODUCTION: Traumatic fractures of the neck of the femur are rare injuries in younger patients between 15 and 50 years old. The short-term and long-term complications may cause substantial problems, in particular non-union and avascular necrosis (AVN) of the head of the femur. In the literature (and from some experts) the impression is occasionally given that there might be "proven" successful therapeutic procedures. METHODS: For this purpose we retrospectively analysed follow-up-data from our own patients in the years 2003-2007 and compared them with the literature. We identified 23 of a total of 376 patients with a femoral neck fracture as a cohort being younger than 50 years. 17 of those 23 patients were treated with an internal fixation. We were able to collect and analyse complete clinical and radiological data of 11 of these 17 patients 4.2 years after surgery. RESULTS: The mean interval between accident and surgery was 22 hours. Only one of the patients developed an AVN after internal fixation of the fracture and was implanted a total hip replacement 18 months postoperatively. There was no non-union of the femoral neck The clinical outcome after 4.2 years was very good. The mean Harris Hip Score was 95 points (of a max. of 100 pts.). CONCLUSIONS: The osteosynthesis of femoral neck fractures in younger patients showed good results and a low risk of AVN and non-union. Therefore the internal fixation of the femoral neck fracture should be preferred for the younger patients instead of a primary total hip replacement.

[Fractures of the neck of the femur in younger patients (15-50 years old). Systematic literature research on medial fractures of the neck of the femur in young patients]. / Schenkelhalsfrakturen bei jüngeren Patienten (15-50 Jahre). Systematische Literaturrecherche zur medialen Schenkelhalsfraktur beim jungen Patienten.

Non-pathologic fractures of the neck of the femur in younger patients aged between 15 and 50 years old are rare injuries. These are so-called effectual injuries with very high energy induction due to traffic accidents, falls and sport accidents, causing healthy bones to be fractured and often leading to multiple injuries. The short-term and long-term complications of such injuries sometimes give rise to substantial problems, in particular from non-union fractures and avascular necrosis of the head of the femur. In the literature (and from some experts) the impression is occasionally given that there might be "proven" successful therapeutic procedures for the methods and in particular the timing of treatment of fractures of the neck of the femur in younger patients. This presentation has gone so far that in some cases the term "treatment malpractice" has been used in legal disputes (and judgments) (Judgment IU 5146/00, Higher Regional Court Munich; 2O 861/07 Hei, Regional District Court Ansbach; 118C 421/05, District Court Cologne). The authors have often been called upon as medical experts to comment on the current state of medical knowledge on the question of the biology of healing of fractures of the neck of the femur and the question of"verified" therapy strategies. With this in mind this article is designed to give a review of the current state of proven knowledge according to the available clinical and experimental data and last but not least to stimulate constructive discussion.

A hypersaline microbial mat from the Pacific Atoll Kiritimati: insights into composition and carbon fixation using biomarker analyses and a 13C-labeling approach.

Modern microbial mats are widely recognized as useful analogs for the study of biogeochemical processes relevant to paleoenvironmental reconstruction in the Precambrian. We combined microscopic observations and investigations of biomarker composition to investigate community structure and function in the upper layers of a thick phototrophic microbial mat system from a hypersaline lake on Kiritimati (Christmas Island) in the Northern Line Islands, Republic of Kiribati. In particular, an exploratory incubation experiment with (13)C-labeled bicarbonate was conducted to pinpoint biomarkers from organisms actively fixing carbon. A high relative abundance of the cyanobacterial taxa Aphanocapsa and Aphanothece was revealed by microscopic observation, and cyanobacterial fatty acids and hydrocarbons showed (13)C-uptake in the labeling experiment. Microscopic observations also revealed purple sulfur bacteria (PSB) in the deeper layers. A cyclic C(19:0) fatty acid and farnesol were attributed to this group that was also actively fixing carbon. Background isotopic values indicate Calvin-Benson cycle-based autotrophy for cycC(19:0) and farnesol-producing PSBs. Biomarkers from sulfate-reducing bacteria (SRB) in the top layer of the mat and their (13)C-uptake patterns indicated a close coupling between SRBs and cyanobacteria. Archaeol, possibly from methanogens, was detected in all layers and was especially abundant near the surface where it contained substantial amounts of (13)C-label. Intact glycosidic tetraether lipids detected in the deepest layer indicated other archaea. Large amounts of ornithine and betaine bearing intact polar lipids could be an indicator of a phosphate-limited ecosystem, where organisms that are able to substitute these for phospholipids may have a competitive advantage.

[A computer-assisted system for diagnosing rhinologic function]. / Computergestütztes System zur rhinologischen Funktionsdiagnostik.

We describe the new computerized rhinologic diagnostic system "CARIMA", a software-controlled system based on a measuring head and a PC. The currently available software allows active anterior rhinomanometry to be carried out with a special program for the nasal allergen test, as well as active posterior rhinomanometry and the determination of the laryngotracheal resistance in patients with an open tracheostoma. The measurement procedure is controlled by the patient by watching the screen during data collecting. The breaths are averaged after curve correction by splining, introducing a time-referred system into the computerized rhinomanometry. The advantage of the method is a detailed analysis of the increasing and decreasing part of the inspiratory and exspiratory half-wave, allowing clinical conclusions to be made about the nasal valve.

The programming of structural properties of movement sequences.

The present paper investigates the role of abstract structural properties in the programming and execution of movement sequences. Three experiments, using converging methods, demonstrate that the motor system represents the abstract structural properties of movement sequences. The first two experiments show that hierarchical structures over a sequence of tapping movements can be used to prepare the motor program, even if the specific elements of the sequence are still unknown. Experiment 2 also shows that the preliminary programming of structural properties of a movement sequence takes more time than the programming of specific elements (start elements). Experiment 3 suggests that abstract structural properties can be generalized from a special sequence and that they are transferable to other sequences. Abstract structural properties are assumed to be an important component of generalized motor programs.