Sebastian Stern

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Use of multiplied viable cells from the nucleus pulposus in altered discs, following in vitro cultivation, may be a promising therapy for degenerative disc disease. Up till now, alginate has been used as a three-dimensional cell carrier to cultivate nucleus pulposus cells. However, the biocompatibility of the alginate, which depends on the composition and(More)
OBJECTIVE Treatment of fractures of the proximal femur by open reduction and internal fixation is prone to complications and frequently requiring secondary joint replacement. The aim of the present study was to examine the results of total hip arthroplasty as a salvage procedure for failed internal fixation of femoral or acetabular fractures. PATIENTS AND(More)
In this paper, lattice-reduction-aided and integerforcing equalization are contrasted. In both approaches, the determination of an integer matrix is essential. The different criteria for this calculation available in the literature are summarized in a unified way. A new factorization algorithm for obtaining the integer matrix is proposed. Via extensive(More)
Lattice-reduction-aided (LRA) equalization techniques have become very popular in multiple-input/multiple-output (MIMO) multiuser communication as they obtain the full diversity order of the MIMO channel. For joint transmitter-side LRA preequalization or precoding on the broadcast channel, the signal constellation is required to be periodically extendable,(More)
Repair of degenerated intervertebral discs by engineered tissue is a clinical challenge in spinal surgery. Prerequisites are cultivation of intervertebral disc cells and determination of their biologic properties. The influence of disc damage in different spinal disorders on the outcome of disc cell cultures has not been discussed previously. This study(More)
Lattice-reduction-aided preequalization (LRA PE) is a powerful technique for interference handling on the multi-user multiple-input/multiple-output (MIMO) broadcast channel. However, recent advantages in the strongly related field of compute-and-forward and integer-forcing equalization have raised the question, if the factorization task present in LRA PE is(More)
Over the last few years, network MIMO or distributed MIMO has gained enormous interest in research and meanwhile is a candidate for future communication systems. However, existing techniques handling the multi-user interference, e.g., linear preequalization (LPE) or TomlinsonHarashima precoding (THP), assume full cooperation between the base stations. This(More)
In this paper, a new class of space-time block codes is proposed. The new construction is based on finite-field rank-metric codes in combination with a rank-metric-preserving mapping to the set of Eisenstein integers. It is shown that these codes achieve maximum diversity order and improve upon existing constructions. Moreover, a new decoding algorithm for(More)
We present a new approach for assessing the instantaneous power distributions of the continuous-time transmit signal (i.e., after pulse shaping) in single- and multi-carrier transmission schemes. On the one hand, an efficient calculation of the distribution for single-carrier signals via the fast Fourier transform (FFT) is given. On the other hand, tight(More)