Eigentümliche morphologische Anpassung einesBatrachospermum gegen mechanische Schädigung in fließendem Wasser

Zusammenfassung Ein neues, in verschiedener Hinsicht interessantesBatrachospermum aus dem engeren Verwandtschaftskreis vonB. vagum wird beschrieben und diskutiert. Es handelt sich dabei um eine Form von Stromschnellen des brasilianischen Rio Negro. Sie ist besonders durch die eigentümlich umgewandelte Berindung (der Zentralachse) bemerkenswert: Die Berindungsfäden umhüllen bei ihr nicht wie gewöhnlich die Internodialzellen, sondern wachsen in der Regel abaxial und bedecken die ganzen Sprosse von außen mit locker niederlaufenden, jedoch starken und elastischen Fasern. Biologisch erfüllen sie offensichtlich unter anderem die Funktion einer höchst wirksamen Schutzeinrichtung gegen mögliche mechanische Schädigungen vor allem der empfindlichen Assimilations-und Reproduktionssysteme im wirbelnden Wasser. Eine Tendenz zur Auflockerung der Berindung ist freilich schon bei dem gewöhnlichen, für lenitische, dystrophe Gewässer charakteristischemB. vagum festzustellen. Die neue Alge, die var.periplocum genannt wird, zeigt auch in den meisten anderen vegetativen Merkmalen wie in der weitgehenden Rückbildung der sexuellen Reproduktion ihre nahe Verwandtschaft mitB. vagum an. Als ein vermittelndes Glied in dieser Entwicklungsreihe konnte dabei noch eine weitere Form derselben Art aus Venezuela angeführt werden.Herrn Prof. Dr. L.Geitler zum 70. Geburtstag gewidmet.     

Nesting habitat overlap between the Common Buzzard Buteo buteo and the Lesser Spotted Eagle Clanga pomarina for conservation planning in Natura 2000 sites

Capsule: The nesting habitat of the Common Buzzard Buteo buteo and Lesser Spotted Eagle Clanga pomarina extensively overlap, indicating that they exploit similar resources.

Aim: We aimed to determine the overlap in the nest platforms, nest trees and nest stands used by these raptors, find any evidence for the avoidance of the larger Lesser Spotted Eagle by the smaller Common Buzzard, and provide conservation implications for habitat protection of the former species in habitats that overlap extensively.

Methods: Nest sites were mapped during 2012–2014 in the Bir?ai Forest Spatial Protection Area, northern Lithuania. Fifty-three nest sites occupied by Common Buzzards and 26 by Lesser Spotted Eagles were compared.

Results: The nest platforms of both raptors were similarly placed in the tree canopies. Most Lesser Spotted Eagle nests were built in spruce, while the Common Buzzard usually nested in birch. The nest stands of the eagles were on wetter soil and located closer to the forest edge than those of the buzzards, otherwise, the nest stands did not differ significantly. There was no evidence for spatial avoidance of the larger raptor by the Common Buzzard.

Conclusions: The different components of the nesting habitats extensively overlapped, and the distribution of the interspecific pairs lacked spatial avoidance. We suggest that the nest sites of both raptors were a largely shared resource, especially if located close to the forest edges. We propose, as a rule of thumb, applying protection by way of buffer zones around buzzard nest sites if they are located close to eagle nest sites and the forest edge.     

Biomechanical and viscoelastic properties of skin,SMAS, and composite flaps as they pertain to rhytidectomy

Previous studies have focused on biomechanical and viscoelastic properties of the superficial musculoaponeurotic system (SMAS) flap and the skin flap lifted in traditional rhytidectomy procedures. The authors compared these two layers with the composite rhytidectomy flap to explain their clinical observations that the composite dissection allows greater tension and lateral pull to be placed on the facial and cervical flaps, with less long-term stress-relaxation and tissue creep. Eight fresh cadavers were dissected by elevating flaps on one side of the face and neck as skin and SMAS flaps and on the other side as a standard composite rhytidectomy flap. The tissue samples were tested for breaking strength, tissue tearing force, stress-relaxation, and tissue creep. For breaking strength, uniform samples were pulled at a rate of 1 inch per minute, and the stress required to rupture the tissues was measured. Tissue tearing force was measured by attaching a 3-0 suture to the tissues and pulling at the same rate as that used for breaking strength. The force required to tear the suture out of the tissues was then measured. Stress-relaxation was assessed by tensing the uniformly sized strips of tissue to 80 percent of their breaking strength, and the amount of tissue relaxation was measured at 1-minute intervals for a total of 5 minutes. This measurement is expressed as the percentage of tissue relaxation per minute. Tissue creep was assessed by using a 3-0 suture and calibrated pressure gauge attached to the facial flaps. The constant tension applied to the flaps was 80 percent of the tissue tearing force. The distance crept was measured in millimeters after 2 and 3 minutes of constant tension. Breaking strength measurements demonstrated significantly greater breaking strength of skin and composite flaps as compared with SMAS flaps (p < 0.05). No significant difference was noted between skin and composite flaps. However, tissue tearing force demonstrated that the composite flaps were able to withstand a significantly greater force as compared with both skin and SMAS flaps (p < 0.05). Stress-relaxation analysis revealed the skin flaps to have the highest degree of stress-relaxation over each of five 1-minute intervals. In contrast, the SMAS and composite flaps demonstrated a significantly lower degree of stress-relaxation over the five 1-minute intervals (p < 0.05). There was no difference noted between the SMAS flaps and composite flaps with regard to stress-relaxation. Tissue creep correlated with the stress-relaxation data. The skin flaps demonstrated the greatest degree of tissue creep, which was significantly greater than that noted for the SMAS flaps or composite flaps (p < 0.05). Comparison of facial flaps with cervical flaps revealed that cervical skin, SMAS, and composite flaps tolerated significantly greater tissue tearing forces and demonstrated significantly greater tissue creep as compared with facial skin, SMAS, and composite flaps (p < 0.05). These biomechanical studies on facial and cervical rhytidectomy flaps indicate that the skin and composite flaps are substantially stronger than the SMAS flap, allowing significantly greater tension to be applied for repositioning of the flap and surrounding subcutaneous tissues. The authors confirmed that the SMAS layer exhibits significantly less stress-relaxation and creep as compared with the skin flap, a property that has led aesthetic surgeons to incorporate the SMAS into the face lift procedure. On the basis of the authors' findings in this study, it seems that that composite flap, although composed of both the skin and SMAS, acquires the viscoelastic properties of the SMAS layer, demonstrating significantly less stress-relaxation and tissue creep as compared with the skin flap. This finding may play a role in maintaining long-term results after rhytidectomy. In addition, it is noteworthy that the cervical flaps, despite their increased strength, demonstrate significantly greater tissue creep as compared with facial flaps, suggesting earlier relaxation of the neck as compared with the face after rhytidectomy.     

Size of the pores created by an electric pulse: Microsecond vs millisecond pulses

Here, the sizes of the pores created by square-wave electric pulses with the duration of 100μs and 2ms are compared for pulses with the amplitudes close to the threshold of electroporation. Experiments were carried out with three types of cells: mouse hepatoma MH-22A cells, Chinese hamster ovary (CHO) cells, and human erythrocytes. In the case of a short pulse (square-wave with the duration of 100μs or exponential with the time constant of 22μs), in the large portion (30-60%) of electroporated (permeable to potassium ions) cells, an electric pulse created only the pores, which were smaller than the molecule of bleomycin (molecular mass of 1450Da, r≈0.8nm) or sucrose (molecular mass of 342.3Da, radius-0.44-0.52nm). In the case of a long 2-ms duration pulse, in almost all cells, which were electroporated, there were the pores larger than the molecules of bleomycin and/or sucrose. Kinetics of pore resealing depended on the pulse duration and was faster after the shorter pulse. After a short 100-μs duration pulse, the disappearance of the pores permeable to bleomycin was completed after 6-7min at 24-26°C, while after a long 2-ms duration pulse, this process was slower and lasted 15-20min. Thus, it can be concluded that a short 100-μs duration pulse created smaller pores than the longer 2-ms duration pulse. This could be attributed to the time inadequacy for pores to grow and expand during the pulse, in the case of short pulses.     

Oxidative effects of nanosecond pulsed electric field exposure in cells and cell-free media

Nanosecond pulsed electric field (nsPEF) is a novel modality for permeabilization of membranous structures and intracellular delivery of xenobiotics. We hypothesized that oxidative effects of nsPEF could be a separate primary mechanism responsible for bioeffects. ROS production in cultured cells and media exposed to 300-ns PEF (1-13kV/cm) was assessed by oxidation of 2',7'-dichlorodihydrofluoresein (H(2)DCF), dihidroethidium (DHE), or Amplex Red. When a suspension of H(2)DCF-loaded cells was subjected to nsPEF, the yield of fluorescent 2',7'-dichlorofluorescein (DCF) increased proportionally to the pulse number and cell density. DCF emission increased with time after exposure in nsPEF-sensitive Jurkat cells, but remained stable in nsPEF-resistant U937 cells. In cell-free media, nsPEF facilitated the conversion of H(2)DCF into DCF. This effect was not related to heating and was reduced by catalase, but not by mannitol or superoxide dismutase. Formation of H(2)O(2) in nsPEF-treated media was confirmed by increased oxidation of Amplex Red. ROS increase within individual cells exposed to nsPEF was visualized by oxidation of DHE. We conclude that nsPEF can generate both extracellular (electrochemical) and intracellular ROS, including H(2)O(2) and possibly other species. Therefore, bioeffects of nsPEF are not limited to electropermeabilization; concurrent ROS formation may lead to cell stimulation and/or oxidative cell damage.     

Periumbilical rectus abdominis perforator preservation significantly reduces superficial wound complications in "separation of parts" hernia repairs

Midline ventral hernia repair with bilateral sliding myofascial rectus abdominis flaps, or the "separation of parts" technique, has low hernia recurrence rates. However, this technique, as originally described, creates massively undermined skin and subcutaneous tissue flaps. These undermined skin flaps can suffer marginal skin loss, fat necrosis, and delayed wound healing. The authors propose that preserving the periumbilical rectus abdominis perforators to the abdominal skin flaps will decrease the prevalence of postoperative superficial wound complications. A retrospective review of 66 consecutive, large, midline hernia repairs using a separation of parts technique was undertaken to identify any correlation between the preservation of periumbilical rectus abdominis perforators to the skin flaps and the prevalence of postoperative wound complications. In 25 cases, the standard separation of parts technique was performed with wide undermining of the skin and subcutaneous tissues. In 41 cases, the modified separation of parts technique was performed with maintenance of the periumbilical rectus abdominis perforators to the abdominal skin flaps.Comparison of these two groups revealed no difference in age; sex; body mass index; initial hernia size on physical examination; prevalence of smoking, diabetes, or steroid use; or prevalence of a simultaneous intraabdominal procedure. A statistically significant difference was noted in postoperative wound complications between the two groups (p < 0.05). Of patients who underwent the standard separation of parts technique, five of 25 patients (20 percent) had wound complications as compared with one of 41 patients (2 percent) who underwent the modified separation of parts technique with perforator preservation. The postoperative hernia recurrence (7 percent and 8 percent, respectively) and hematoma (4 percent and 2 percent, respectively) rates were similar in both groups. A trend of increased wound complications was noted when separation of parts was combined with an intraabdominal procedure (18 percent versus 3 percent, p = 0.08). Interestingly, within this group, the modified separation of parts technique with preservation of the periumbilical rectus abdominis perforators demonstrated a trend of fewer wound complications as compared with the standard separation of parts technique (7 percent versus 31 percent, p = 0.15). The authors conclude that preservation of the periumbilical rectus abdominis perforators significantly reduces the prevalence of major postoperative superficial wound complications in separation of parts hernia repairs. Simultaneous intraabdominal procedures with separation of parts hernia repairs seem to increase the prevalence of wound complications. This increased prevalence of wound complications seems to be minimized when the modified separation of parts technique is performed.     

Coexistence of protected avian predators: does a recovering population of White-tailed Eagle threaten to exclude other avian predators?

The processes of competition and predation determine the degree to which species can coexist; the importance of competition in particular has been emphasized at high trophic levels. Competition exclusion will occur when habitat overlap between sympatric species is high. In this study, we investigated nesting habitat overlap between internationally protected diurnal tree-nesting avian predators of central Europe, namely, White-tailed Eagle (Haliaeetus albicilla), Lesser Spotted Eagle (Aquila pomarina), Black Stork (Ciconia nigra), and Osprey (Pandion haliaetus). We found significantly different nesting habitats among the study species and suggest that this could be a consequence of the resource-based segregation, but not a consequence of asymmetrical interspecific competition. The results also show that habitat of the recovering populations of White-tailed Eagle overlapped with the habitat used by the Lesser Spotted Eagle, Black Stork, and Osprey to varying extents with a niche overlap values being below the competition exclusion threshold. Nevertheless, we suggest that competition by White-tailed Eagle at a population level may limit Osprey, though not Lesser Spotted Eagle or Black Stork.     

Gloeococcus bavaricus n. sp. undCoelastrella compacta n. sp.

Ohne Zusammenfassung