[Treatment of unicompartmental osteoarthritis of the knee]. / Therapie der unikompartimentellen Gonarthrose.

Osteoarthritis of the knee is one of the most important degenerative joint diseases in the clinical routine. The treatment of knee osteoarthritis is not only based on the stage, symptoms and duration of the joint disease, but also depends on the existing arthrosis pattern. In the case of unicompartmental arthrosis, damage typical for osteoarthritis is limited to just one joint compartment. Both the conservative and the surgical treatment of unicompartmental osteoarthritis of the knee have to respect the individual characteristics of the respective forms of osteoarthritis. In the context of this manuscript, the genesis, the diagnostics and the guideline-based stage-adapted conservative and operative treatment of unicompartmental osteoarthritis of the knee are addressed.

Scaling up conservation agriculture: An exploration of challenges and opportunities through a stakeholder engagement process.

Increasing the resilience of agricultural landscapes requires fundamental changes to the dominant commodity production model, including incorporating practices such as reduced tillage, cover cropping, and extended rotations that reduce soil disturbance while increasing biological diversity. Increasing farmer adoption of these conservation systems offers the potential to transform agriculture to a more vibrant, resilient system that protects soil, air, and water quality. Adoption of these resilience practices is not without significant challenges. This paper presents findings from a participatory effort to better understand these challenges and to develop solutions to help producers overcome them. Through repeated, facilitated discussions with farmers and agricultural and conservation professionals across the U.S. state of Michigan, we confronted the policy, economic, and structural barriers that are inhibiting broader adoption of conservation systems, as well as identified policies, programs, and markets that can support their adoption. What emerged was a complex picture and dynamic set of challenges at multiple spatial scales and across multiple domains. The primary themes emerging from these discussions were barriers and opportunities, including markets, social networks, human capital, and conservation programs. Exacerbating the technical, agronomic, and economic challenges farmers face at the farm level, there are a host of community constraints, market access and availability problems, climatic and environmental changes, and policies (governmental and corporate) that cross-pressure farmers when it comes to making conservation decisions. Understanding these constraints is critical to developing programs, policies, and state and national investments that can drive adoption of conservation agriculture.

Erratum to "Evaluation of MoPyC-prosthesis implantation and the use of angular stable plates in the treatment of comminuted radial head fractures" [J. Orthop. 16 (2019) 288-293].

[This corrects the article DOI: 10.1016/j.jor.2019.03.002.].

Evaluation of MoPyC-prosthesis implantation and the use of angular stable plates in the treatment of comminuted radial head fractures.

OBJECTIVE: Comminuted radial head fractures are disproportionately often accompanied by injuries of the bone or ligaments and can be treated in different ways. METHODS: 15 patients with a comminuted radial head fracture were treated with an angular stable plate (=G1) and 8 with a MoPyC-prosthesis (=G2). RESULTS: G1 shows an average Morrey-score of 83,87 points. Complications occurred in 5/15 patients. Within G2 an average Morrey-score of 86 was achieved. Complications could be shown in 2/8 patients. CONCLUSION: Both the treatment provides a clear individual benefit for the patients and predict promising results for the treatment of comminuted radial head fractures.

Evaluation of MoPyC-prosthesis implantation and the use of angular stable plates in the treatment of comminuted radial head fractures.

OBJECTIVE: Comminuted radial head fractures are disproportionately often accompanied by injuries of the bone or ligaments and can be treated in different ways. METHODS: 15 patients with a comminuted radial head fracture were treated with an angular stable plate (=G1) and 8 with a MoPyC-prosthesis (=G2). RESULTS: G1 shows an average Morrey-score of 83,87 points. Complications occurred in 5/15 patients. Within G2 an average Morrey-score of 86 was achieved. Complications could be shown in 2/8 patients. CONCLUSION: Both the treatment provides a clear individual benefit for the patients and predict promising results for the treatment of comminuted radial head fractures.

[Ultrasound diagnostics for myotendinous injuries and insertion tendinopathies of the elbow joint]. / Ultraschalldiagnostik bei muskuloligamentären Verletzungen sowie Insertionstendinopathien am Ellenbogengelenk.

INTRODUCTION: Acute capsular injuries of the elbow joint and its ligaments predominantly occur after joint dislocation or subluxation. Together with lateral and medial epicondylitis they represent a common injury pattern in radiology, orthopedic and trauma surgery. CLINICAL ISSUE: Because of the complexity of the elbow joint, knowledge of the elbow dislocation and injury pattern as well as the anatomy is essential in order to adequately estimate the injury severity and joint stability. This is crucial for the correct diagnosis and choice of treatment. Systematic physical examination and careful radiographic evaluation are components of an adequate management of acute soft tissue elbow injuries. DIAGNOSTIC WORK-UP: The cost-effective ultrasound has emerged as a useful imaging modality for the diagnosis of acute joint and soft tissue pathologies especially in the acute phase after injury. Ultrasound as a diagnostic tool enables visualization of motion sequences during dynamic examination and therefore a better understanding of pathologies. Ultrasound examinations of the most common injuries of the elbow joint are presented in this overview.

Options and limits of angle stable plates in the treatment of comminuted radial head fractures.

OBJECTIVE: New angle-stable plates provide more stability and better anatomical fit than previous plates. METHODS: 22 patients treated with an angle-stable plate were included. Postoperative the outcomes were evaluated according to the scoring systems of Morrey, Radin and Riseborough. RESULTS: 3 patients received a score of excellent, 14 good, and 5 satisfactory. We detected 3 cases of implant failure and 2 cases of postoperative neurological damage. 3 patientes received a radial head necrosis. CONCLUSIONS: Our results show that the angle-stable radial head locking plate can only be used in limited cases in the treatment of multi-fragment radial head fractures.

Rise Time Reduction of Thermal Actuators Operated in Air and Water through Optimized Pre-Shaped Open-Loop Driving.

Electrothermal actuators have many advantages compared to other actuators used in Micro-Electro-Mechanical Systems (MEMS). They are simple to design, easy to fabricate and provide large displacements at low voltages. Low voltages enable less stringent passivation requirements for operation in liquid. Despite these advantages, thermal actuation is typically limited to a few kHz bandwidth when using step inputs due to its intrinsic thermal time constant. However, the use of pre-shaped input signals offers a route for reducing the rise time of these actuators by orders of magnitude. We started with an electrothermally actuated cantilever having an initial 10-90% rise time of 85 µs in air and 234 µs in water for a standard open-loop step input. We experimentally characterized the linearity and frequency response of the cantilever when operated in air and water, allowing us to obtain transfer functions for the two cases. We used these transfer functions, along with functions describing desired reduced rise-time system responses, to numerically simulate the required input signals. Using these pre-shaped input signals, we improved the open-loop 10-90% rise time from 85 µs to 3 µs in air and from 234 µs to 5 µs in water, an improvement by a factor of 28 and 47, respectively. Using this simple control strategy for MEMS electrothermal actuators makes them an attractive alternative to other high speed micromechanical actuators such as piezoelectric stacks or electrostatic comb structures which are more complex to design, fabricate, or operate.

Thermodynamic integration methods, infinite swapping, and the calculation of generalized averages.

In the present paper we examine the risk-sensitive and sampling issues associated with the problem of calculating generalized averages. By combining thermodynamic integration, stationary phase Monte Carlo, and infinite swapping techniques, we develop an approach for such problems and explore its utility for a prototypical class of applications.

[Diabetes mellitus as a prognostic marker in oropharyngeal and laryngeal squamous cell carcinoma]. / Diabetes mellitus als prognostischer Marker beim Oropharynx- und Larynxkarzinom.

Recent experimental and clinical studies have provided compelling evidence that diabetes mellitus (DM) is an important risk factor in various cancers, and may affect both pathogenesis and prognosis. Additionally, antidiabetic agents such as metformin exhibit an antitumorigenic effect. However, to date there is insufficient knowledge about the role of DM in the pathogenesis and prognosis of head and neck squamous cell carcinoma (HNSCC).In a retrospective monocentric study including 424 patients with SCC of the oropharynx (OPSCC) or larynx (LaSCC), the impact of DM on clinical and histopathologic parameters was investigated. The authors found a rising incidence of DM among LaSCC patients (<10 % until 2005 and 20 % since 2006) and a significant association between DM and clinical and histopathologic features (age, gender, tumor size, and pathologic grading), which depended on the anatomic site. Moreover, a clear trend toward unfavorable progression-free and overall survival of HNSCC patients with DM upon current treatment modalities was evident.The presented data support a relative increase in patients with DM, particularly for LaSCC. This might have a sustained influence on treatment decisions and management, and should be considered in future clinical trials. A better understanding of the cellular and molecular traits of HNSCC in DM could pave the way for innovative therapeutic strategies in terms of personalized medicine.

On performance measures for infinite swapping Monte Carlo methods.

We introduce and illustrate a number of performance measures for rare-event sampling methods. These measures are designed to be of use in a variety of expanded ensemble techniques including parallel tempering as well as infinite and partial infinite swapping approaches. Using a variety of selected applications, we address questions concerning the variation of sampling performance with respect to key computational ensemble parameters.

Spatial Averaging: Sampling Enhancement for Exploring Configurational Space of Atomic Clusters and Biomolecules.

Spatial averaging Monte Carlo (SA-MC) is an efficient algorithm dedicated to the study of rare-event problems. At the heart of this method is the realization that from the equilibrium density a related, modified probability density can be constructed through a suitable transformation. This new density is more highly connected than the original density, which increases the probability for transitions between neighboring states, which in turn speeds up the sampling. The first successful investigations included the diffusion of small molecules in condensed phase environments and characterization of the metastable states of the migration of the CO ligand in myoglobin. In the present work, a general and robust implementation including rotational and torsional moves in the CHARMM molecular modeling software is introduced. Also, a procedure to estimate unbiased properties is proposed in order to compute thermodynamic observables. These procedures are suitable to study a range of topical systems including Lennard-Jones clusters of different sizes and the blocked alanine dipeptide (Ala)2 in implicit and explicit solvent. In all cases, SA-MC is found to outperform standard Metropolis simulations in sampling configurational space at little extra computational expense. The results for (Ala)2 in explicit solvent are in good agreement with previous umbrella sampling simulations.

Overcoming the Rare Event Sampling Problem in Biological Systems with Infinite Swapping.

Infinite swapping (INS) is a recently developed method to address the rare event sampling problem. For INS, an expanded computational ensemble composed of a number of replicas at different temperatures is used, similar to the widely used parallel tempering (PT) method. While the basic concept of PT is to sample various replicas of the system at different temperatures and exchange information between the replicas occasionally, INS uses the symmetrized distribution of configurations in temperature space, which corresponds to the infinite swapping limit of PT. The effect of this symmetrization and the enhanced information exchange between replicas is evaluated for three different biological systems representing different sampling problems in biology: (1) blocked alanine dipeptide, which is a small system and therefore optimal to evaluate sampling efficiency quantitatively, (2) Villin headpiece, which is used as a test case for the protein folding process, and (3) neuroglobin, which is used to evaluate the effects of enhanced information exchange between replicas for sampling the substate space of a folded protein. For these three test systems, PINS is compared to PT, and it is found that in all cases the sampling with PINS is substantially more efficient.

Rare-event sampling: occupation-based performance measures for parallel tempering and infinite swapping Monte Carlo methods.

In the present paper we identify a rigorous property of a number of tempering-based Monte Carlo sampling methods, including parallel tempering as well as partial and infinite swapping. Based on this property we develop a variety of performance measures for such rare-event sampling methods that are broadly applicable, informative, and straightforward to implement. We illustrate the use of these performance measures with a series of applications involving the equilibrium properties of simple Lennard-Jones clusters, applications for which the performance levels of partial and infinite swapping approaches are found to be higher than those of conventional parallel tempering.

Atomistic modeling of thermodynamic equilibrium and polymorphism of iron.

We develop two new modified embedded-atom method (MEAM) potentials for elemental iron, intended to reproduce the experimental phase stability with respect to both temperature and pressure. These simple interatomic potentials are fitted to a wide variety of material properties of bcc iron in close agreement with experiments. Numerous defect properties of bcc iron and bulk properties of the two close-packed structures calculated with these models are in reasonable agreement with the available first-principles calculations and experiments. Performance at finite temperatures of these models has also been examined using Monte Carlo simulations. We attempt to reproduce the experimental iron polymorphism at finite temperature by means of free energy computations, similar to the procedure previously pursued by Müller et al (2007 J. Phys.: Condens. Matter 19 326220), and re-examine the adequacy of the conclusion drawn in the study by addressing two critical aspects missing in their analysis: (i) the stability of the hcp structure relative to the bcc and fcc structures and (ii) the compatibility between the temperature and pressure dependences of the phase stability. Using two MEAM potentials, we are able to represent all of the observed structural phase transitions in iron. We discuss that the correct reproductions of the phase stability among three crystal structures of iron with respect to both temperature and pressure are incompatible with each other due to the lack of magnetic effects in this class of empirical interatomic potential models. The MEAM potentials developed in this study correctly predict, in the bcc structure, the self-interstitial in the (110) orientation to be the most stable configuration, and the screw dislocation to have a non-degenerate core structure, in contrast to many embedded-atom method potentials for bcc iron in the literature.

An infinite swapping approach to the rare-event sampling problem.

We describe a new approach to the rare-event Monte Carlo sampling problem. This technique utilizes a symmetrization strategy to create probability distributions that are more highly connected and, thus, more easily sampled than their original, potentially sparse counterparts. After discussing the formal outline of the approach and devising techniques for its practical implementation, we illustrate the utility of the technique with a series of numerical applications to Lennard-Jones clusters of varying complexity and rare-event character.

Convergence characteristics of the cumulant expansion for Fourier path integrals.

The cumulant representation of the Fourier path integral method is examined to determine the asymptotic convergence characteristics of the imaginary-time density matrix with respect to the number of path variables N included. It is proved that when the cumulant expansion is truncated at order p, the asymptotic convergence rate of the density matrix behaves like N(-(2p+1)). The complex algebra associated with the proof is simplified by introducing a diagrammatic representation of the contributing terms along with an associated linked-cluster theorem. The cumulant terms at each order are expanded in a series such that the asymptotic convergence rate is maintained without the need to calculate the full cumulant at order p. Using this truncated expansion of each cumulant at order p, the numerical cost in developing Fourier path integral expressions having convergence order N(-(2p+1)) is shown to be approximately linear in the number of required potential energy evaluations making the method promising for actual numerical implementation.

Spatial averaging for small molecule diffusion in condensed phase environments.

Spatial averaging is a new approach for sampling rare-event problems. The approach modifies the importance function which improves the sampling efficiency while keeping a defined relation to the original statistical distribution. In this work, spatial averaging is applied to multidimensional systems for typical problems arising in physical chemistry. They include (I) a CO molecule diffusing on an amorphous ice surface, (II) a hydrogen molecule probing favorable positions in amorphous ice, and (III) CO migration in myoglobin. The systems encompass a wide range of energy barriers and for all of them spatial averaging is found to outperform conventional Metropolis Monte Carlo. It is also found that optimal simulation parameters are surprisingly similar for the different systems studied, in particular, the radius of the point cloud over which the potential energy function is averaged. For H(2) diffusing in amorphous ice it is found that facile migration is possible which is in agreement with previous suggestions from experiment. The free energy barriers involved are typically lower than 1 kcal/mol. Spatial averaging simulations for CO in myoglobin are able to locate all currently characterized metastable states. Overall, it is found that spatial averaging considerably improves the sampling of configurational space.

Finite-temperature quantum simulations of mixed rare gas clusters.

Finite-temperature quantum Monte Carlo simulations are presented for mixed neon/argon rare gas clusters containing up to n=10 atoms. For the smallest clusters (n=3) comparison with rigorous bound state calculations and experiments shows that the present approach is accurate to within fractions of wavenumbers for energies and to within a few percent or better for rotational constants. For larger cluster sizes, for which no rigorous quantum calculations are available, comparison with experiment becomes even more favorable. In all simulations accurate pair potentials for the rare gas-rare gas interactions are employed and comparison with high-level electronic structure calculations suggest that many-body interactions play a minor role. For the largest clusters investigated (Ne(4)Ar(6)) gradual melting of the neon phase is observed while the argon-phase remains structurally intact.