Bone Graft Substitutes

__Abstract__ Bone grafting was established in the 19th century and has become a common procedure in which bone defects are filled with bone grafts or bone graft substitutes. Bone defects that require bone grafting are encountered in approximately 10% of trauma and orthopaedic surgeries 1. A broad range of different bone grafts or bone graft substitutes have been developed during the past fifty years. All these bone grafts or bone graft substitutes have their strengths and weaknesses, confronting each surgeon with the difficult task to select the most suitable bone graft or bone graft substitute for each trauma and orthopaedic surgical procedure that requires bone grafting

Adaptive streaming of MPEG-based audio/video content over wireless networks

This paper describes a method for robust streaming of combined MPEG audio/video content (encoded either with MPEG-2 or MPEG-4/H.264) over in-home wireless networks. We make use of currently used content distribution format (MPEG Transport Stream) and network protocols (either RTP or TCP/HTTP). The transmitted bit-rate is constantly adapted to the available network bandwidth, such that audio and video artifacts caused by packet loss are avoided. Bit-rate adaptation is achieved by using a packet scheduling technique called I-Frame Delay (IFD), which performs priority-based frame dropping upon insufficient bandwidth. We show an implementation using RTP and an implementation using TCP. Measurements on a real-life demonstrator set-up demonstrate the effectiveness of our approach

The response time distribution in a multi-processor database with single queue static locking

A transaction scheduling mechanism is designed for a shared??memory?? multi??processor database system??. The scheduler used is a variant of static locking?? adapted for real??time and more than one processor??. It is assumed that transactions arrive according to a Poisson process?? execution times of transactions are independent and exponentially distributed?? and all transactions use the same number of data items?? The system is then represented as a Markov model??. A steady state is derived from this model??. By examining the path through the system of a single transaction,?? a recursive relation that describes all moments of a transaction's response time is derived.?? The moments are obtained from this relation with dynamic programming??. The response time distribution is approximated by fi??tting a distribution to the ??first two moments??. Simulation shows that this approximation gives excellent results??

Preoperative embolization in surgical treatment of long bone metastasis: A systematic literature review

Surgery of long bone metastases is associated with a significant risk of perioperative blood loss, which may necessitate blood transfusion. Successful embolization (> 70% obliteration of vascularity) can be achieved in 36-75% of cases. The reported rate of embolization-related complications is 0-9%. Three out of six level III evidence studies showed a reduction in perioperative blood loss and/orblood transfusion requirement after preoperative embolization of renal cell carcinoma metastasis in long bones; three out of six studies did not. One level III evidence study did not show a reduction in perioperative blood loss and/or transfusion requirement after preoperative embolization of hepatocellular carcinoma metastases in long bones. There were no studies found that support preoperative embolization of thyroid metastases or other frequent long bone metastases (e.g. mamma carcinoma, lung carcinoma, or prostate carcinoma). The clinical level of evidence of the studies found is low and randomized studies taking into account primary tumour, location of metastases and type of surgery are therefore desired

A database for on-line event analysis on a distributed memory machine

Parallel in-memory databases can enhance the structuring and parallelization of programs used in High Energy Physics (HEP). Efficient database access routines are used as communication primitives which hide the communication topology in contrast to the more explicit communications like PVM or MPI. A parallel in-memory database, called SPIDER, has been implemented on a 32 node Meiko CS-2 distributed memory machine. The spider primitives generate a lower overhead than the one generated by PVM or PMI. The event reconstruction program, CPREAD of the CPLEAR experiment, has been used as a test case. Performance measurerate generated by CPLEAR

Bone substitutes in the Netherlands - A systematic literature review

Autologous bone grafting is currently considered as the gold standard to restore bone defects. However, clinical benefit is not guar

Properties of commonly used calcium phosphate cements in trauma and orthopaedic surgery

Introduction Half of the population sustains at least one fracture during their lifetime, and the majority of these fractures heal successfully. Successful fracture healing requires the following five elements; (i) osteogenic cells (e.g., osteoblasts), (ii) osteoinductive stimuli (e.g., bone morphogenetic proteins); (iii) an osteoconductive matrix; (iv) adequate blood and nutrient supply, and (v) sufficient mechanical support. One or more elements can be compromised due to the existence of a bone defect. Bone defects are treated with bone grafts in order to avoid insufficient fracture healing. Insufficient fracture healing is encountered in 5–10% of the fractures, resulting in delayed union, malunion, or non-union