First Case Report of a Near Lethal Envenomation by a Salomonelaps par (Solomons Coral Snake) in the Solomon Islands.

Venomous snake bites in the Solomon Islands can be very dangerous due to lack of access to health care. There are no documented case reports of envenomation by snake bites in the Solomon Islands. This case report highlights the management of a patient with potentially lethal neurotoxicity secondary to a Solomonelaps par (Solomons coral snake) in a low resource setting. This case identifies the potential benefit of further research to determine the incidence of lethal envenomation as well as analysing the venom to determine if any commercially available antivenom would be useful in the treatment of envenomation by Salomonelaps par and other venomous snakes. There should be consideration given to providing education on first aid for people living in remote areas as well as education for health workers.

Development of a micro-mechanical valve in a novel glaucoma implant.

This paper describes methods for design, manufacturing and characterization of a micro-mechanical valve for a novel glaucoma implant. The implant is designed to drain aqueous humour from the anterior chamber of the eye into the suprachoroidal space in case of an elevated intraocular pressure (IOP). In contrast to any existing glaucoma drainage device (GDD), the valve mechanism is located in the anterior chamber and there, surrounded by aqueous humour, immune to fibrosis induced failure. For the prevention of hypotony the micro-mechanical valve is designed to open if the physiological pressure difference between the anterior chamber and the suprachoroidal space in the range of 0.8 mmHg to 3.7 mmHg is exceeded. In particular the work includes: (i) manufacturing and morphological characterization of polymer tubing, (ii) mechanical material testing as basis for (iii) the design of micro-mechanical valves using finite element analysis (FEA), (iv) manufacturing of microstent prototypes including micro-mechanical valves by femtosecond laser micromachining and (v) the experimental fluid-mechanical characterization of the manufactured microstent prototypes with regard to valve opening pressure. The considered materials polyurethane (PUR) and silicone (SIL) exhibit low elastic modulus and high extensibility. The unique valve design enables a low opening pressure of micro-mechanical valves. An ideal valve design for PUR and SIL with an experimentally determined opening pressure of 2 mmHg and 3.7 mmHg is identified. The presented valve approach is suitable for the inhibition of hypotony as a major limitation of today's GDD and will potentially improve the minimally invasive treatment of glaucoma.

A biodegradable slotted tube stent based on poly(L-lactide) and poly(4-hydroxybutyrate) for rapid balloon-expansion.

Safe vascular stent application requires rapid expansion of the stent to minimize the risk of procedural ischemia. While high expansion speeds can be achieved with metallic stents, they are not necessarily feasible with biodegradable polymeric stents due to the viscoelastic material behavior. This study reports on a novel biodegradable polymer blend material based on poly(L-lactide) (PLLA) and poly(4-hydroxybutyrate) (P4HB), and describes the mechanical properties and in vitro degradation behavior of a balloon-expandable slotted tube stent concept. The stent prototypes with nominal dimensions of 6.0 x 25 mm were manufactured by laser machining of solution cast PLLA/P4HB tubes (I.D. = 2.8 mm, d = 300 microm). The stents were expanded within 1 min by balloon inflation to 8 bar, after 5 min preconditioning in 37 degrees C water. Recoil and collapse pressure were 4.2% and 1.1 bar, respectively. During in vitro degradation collapse pressure initially increased to a maximum at 4 w and then decreased thereafter. After 48 w, molecular weight was decreased by 82%. In summary, the PLLA/P4HB slotted tube stents allowed for rapid balloon-expansion and exhibited adequate mechanical scaffolding properties suitable for a broad range of vascular and non-vascular applications.

[Finite element analysis of a cemented ceramic femoral component for the assembly situation in total knee arthroplasty]. / Finite-Elemente-Analyse einer zementierten, keramischen Femurkomponente unter Berücksichtigung der Einbausituation bei künstlichem Kniegelenkersatz.

The femoral components of the total knee replacements are generally made of metal. In contrast, ceramic femoral components promise improved tribological and allergological properties. However, ceramic components present a risk of failure as a result of stress peaks. Stress peaks can be minimised through adequate implant design, proper material composition and optimum force transmission between bone and implant. Thus, the quality of the implant fixation is a crucial factor. The objective of the present study was to analyse the influence of the cement layer thickness on stress states in the ceramic femoral component and in the femur. Two- and three- dimensional finite element analyses of an artificial knee joint with cement layers of different thickness and with an unbalanced cement layer thickness between the ceramic femoral component and the femur were performed. Higher stress regions occurred in the area of force transmission and in the median plane. The maximum calculated stresses were below the accepted tensile strength. Stresses were found to be lower for cement layer thickness of <2.0 mm.