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Introduction: Chondral and osteochondral lesions of the talus (OLTs) remain a challenging issue with numerous operative treatments proposed to date. The aim of this study was to evaluate 1-year follow-up data in the German Cartilage Registry (KnorpelRegister DGOU). Methods: Among 401 patients in the database, 114 patients with a complete 1-year Foot and Ankle Outcome (FAOS) score for subscale Pain as the primary variable were included. A total of 12 different surgical treatments were performed. However, 8 techniques were carried out in negligible numbers of patients (n = 1–3), leaving 89 patients treated with the following techniques: arthroscopic antegrade bone marrow stimulation (group A; n = 32), autologous chondrocyte implantation with autologous cancellous bone grafting (group B; n = 9), matrix-augmented bone marrow stimulation (group C; n = 22), and matrix-augmented bone marrow stimulation with autologous cancellous bone grafting (group D; n = 26). Group differences and possible influencing variables such as age and sex were evaluated. Level of significance was set at p < 0.05 for all statistical tests. Results: All four treatment groups showed significant improvement of the FAOS scores at 1 year postoperatively compared with their preoperative scores. No significant differences were found with respect to score changes among the groups. A positive correlation between FAOS subscale Pain improvement and defect size volume and negative correlations between increasing age and FAOS subscales Sports/Rec and QoL were found. Concomitant ankle stabilization led to greater improvement in FAOS subscales Symptoms and ADL than in patients with no stabilization. FAOS subscale Pain showed greater improvement in women than in men. Conclusion: All analyzed treatment options were effective for treatment of OLTs. In particular, large defects appeared to benefit from treatment. In the presence of concomitant ankle instability, a stabilizing procedure appeared to have a positive impact on the outcome. [ABSTRACT FROM AUTHOR]

We report fluorescence investigations and Raman spectroscopy on colloidal nanodiamonds (NDs) obtained via bead assisted sonic disintegration (BASD) of a polycrystalline chemical vapor deposition film. The BASD NDs contain in situ created silicon vacancy (SiV) centers. Whereas many NDs exhibit emission from SiV ensembles, we also identify NDs featuring predominant emission from a single bright SiV center. We demonstrate oxidation of the NDs in air as a tool to optimize the crystalline quality of the NDs via removing damaged regions resulting in a reduced ensemble linewidth as well as single photon emission with increased purity. We furthermore investigate the temperature dependent zero-phonon-line fine-structure of a bright single SiV center as well as the polarization properties of its emission and absorption. [ABSTRACT FROM AUTHOR]

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Nitrogen-vacancy (NV) centers feature outstanding properties such as a spin coherence time of up to 1 s as well as a level structure offering the possibility to initialize, coherently manipulate, and optically read-out the spin degree of freedom of the ground state. However, only about 3% of their photon emission is channeled into the zero phonon line (ZPL), limiting both the rate of indistinguishable single photons and the signal-to-noise ratio (SNR) of coherent spin-photon interfaces. We here report on the enhancement of the SNR of the optical spin read-out achieved by tuning the mode of a two-dimensional photonic crystal (PhC) cavity into resonance with the NV-ZPL. PhC cavities are fabricated by focused ion beam milling in thin reactive ion etched ultrapure single crystal diamond membranes featuring modes with Q-factors of up to 8250 at mode volumes below one cubic wavelength. NV centers are produced in the cavities in a controlled fashion by a high resolution atomic force microscope implantation technique. On cavity resonance, we observe a lifetime shortening from 9.0 ns to 8.0 ns as well as an enhancement of the ZPL emission by almost one order of magnitude. Although on resonance the collection efficiency of ZPL photons and the spin-dependent fluorescence contrast are reduced, the SNR of the optical spin read-out is almost tripled for the cavity-coupled NV centers. [ABSTRACT FROM AUTHOR]

Introduction: The rationale of focal articular prosthetic resurfacing used as a primary arthroplasty procedure in the treatment of articular cartilage defects is still under debate. Conflicting reports raise concern about high rates of re-operations and continued development of osteoarthritis, while others have reported good outcomes. The goal of this paper is to present the long-term results of two patients with a 12-year follow-up and to report the results of a literature review.Materials and Methods: Two patients (male, 70 years; female 63 years) with a follow-up of 12 years were reviewed. Patients were evaluated with standard radiographs to assess the progression of osteoarthritis (OA), a clinical examination including the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity scale. The literature review was performed using the search terms HemiCAP, focal, femoral, condyle, inlay, and resurfacing to identify articles published in the English language up until September 25, 2016.Results: The clinical and radiographic follow-ups of the patients were 11.9 and 11.8 years, respectively. Both patients were satisfied with their outcome and would have the operation again. Comparing the first postoperative to 12-year follow-up X-rays, the radiographic results demonstrated no signs of periprosthetic loosening, preservation of joint space, and no change in the osteoarthritic stage. KOOS Scores were 86 and 83 for pain, 89 and 93 for symptoms, 88 and 100 for activities of daily living (ADL), 75 and 65 for sports and recreation, and 75 and 81 for quality of life (QOL). The Tegner activity level was 5 and 4. The literature review comprised 6 studies with 169 focal articular prosthetic resurfacing procedures in 169 patients (84 male, 85 female) with a mean age at implantation ranging from 44.7 to 53.7 years and a follow-up range of 20 months to 7 years. Five studies were classified as level 4 and one as level 3. Clinical and radiographic results showed mainly good to excellent outcomes but were different among the studies depending on the indication. Re-operation rates ranged from 0 to 23% depending on the length of follow-up.Conclusions: The results suggest that focal articular prosthetic resurfacing is an effective and safe treatment option in selected cases. [ABSTRACT FROM AUTHOR]

Purpose: This cadaveric study compares the biomechanical properties of femoral graft fixation in ACL reconstruction of either quadriceps or hamstring tendon grafts with four different interference screws. The hypothesis was that quadriceps tendon grafts provide at least equal results concerning gap formation during cyclic loading and ultimate failure load compared to hamstring tendon grafts with four different interference screws.Methods: Eighty porcine femora underwent interference screw fixation of human tendon grafts for ACL reconstruction. Either quadriceps (Q) or hamstring (H) tendon grafts and four different bioabsorbable interference (Wolf (W), Storz (S), Mitek (M), Arthrex (A)) screws were used, resulting in 8 groups with 10 specimens per groups (WQ, WH, SQ, SH, MQ, MH, AQ, AH). Biomechanical analysis included pretensioning the constructs with 60 N for 30 s, then cyclic loading of 500 cycles between 60 and 250 N at 1 Hz in a servohydraulic testing machine, with measurement of elongation and stiffness including video measurements. After this, ultimate failure load and failure mode analysis were performed.Results: No statistically significant difference could be noted between the groups regarding gap formation during cyclic loading [Cycles 21-500 (mm): WQ 3.6 ± 0.8, WH 3.9 ± 1.4, SQ 3.6 ± 0.8, SH 3.3 ± 1.5, MQ 4.3 ± 0.8, MH 4.6 ± 1.0, AQ 4.8 ± 0.8, AH 4.3 ± 1.5, n.s.], stiffness during cyclic loading [Cycles 21-500 (N/mm): WQ 72.9 ± 16.9, WH 71.6 ± 20.7, SQ 69.5 ± 23.9, SH 77.4 ± 25.1, MQ 59.6 ± 11.2, MH 48.4 ± 15.4, AQ 48.8 ± 12.7, AH 51.9 ± 22.2, n.s.], and ultimate failure load [(N): WQ 474.4 ± 88.0, WH 579.3 ± 124.2, SQ 493.9 ± 105.2, SH 576.0 ± 90.4, MQ 478.6 ± 59.0, MH 543.9 ± 119.7, AQ 480.2 ± 93.8, AH 497.8 ± 74.2, n.s.].Conclusions: Quadriceps tendon grafts yield comparable biomechanical results for femoral interference screw fixation in ACL reconstruction compared to hamstring tendon grafts. From a clinical perspective, quadriceps tendon grafts should therefore be considered as a good option in ACL reconstruction in the future. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to analyse and compare the clinical and radiological results after open posterior bone block procedure at long- (LT) and short-term (ST) follow-up. The hypothesis was that placement of a bone block at the posterior glenoid rim in a technique of extending the glenoid surface will create permanent joint stability even in cases with hyperlaxity without a clinically relevant loss of motion or increase in osteoarthritis.Methods: Fifteen consecutive shoulders with recurrent posterior dislocation were evaluated clinically and radiologically. The Rowe score, Western Ontario Shoulder Index, Walch-Duplay score and the Constant-Murley score were used for clinical evaluation. The patients were categorized according to their follow-up period as either ST follow-up (min 12 months) or LT follow-up (min 42 months).Results: The clinical results showed no significant difference between ST (9) and LT (6) with good to very good overall results in the subjective as well as the objective scores (CS, RS, WDS). At LT, most patients felt mild to minor pain under strain. The difference in pain between the groups was not significant. Active ranges of motion and strength assessments were normal in all cases. In one case, recurrent dislocations occurred after bone graft resorption 6 months post-operatively. Only one patient presented mild osteoarthritis, without further progress at follow-up.Conclusion: The open posterior bone block procedure can be a successful treatment option for recurrent posterior shoulder instability at ST and LT follow-up. This series showed a low rate of recurrent dislocations without development or progression of osteoarthritis. Since soft tissue procedures do not always provide satisfying results, the posterior bone block augmentation presents a reliable technique for the treatment of symptomatic posterior instability.Level Of Evidence: Case Series, Treatment Study, Level IV. [ABSTRACT FROM AUTHOR]

Purpose: Outcome assessment is critical in evaluating the efficacy of orthopaedic procedures. The Foot and Ankle Outcome Score (FAOS) is a 42-item questionnaire divided into five subscales, which has been validated in several languages. Germany has no validated outcome score for general foot and ankle pathology. The aim of this study was to develop a German version of the FAOS and to investigate its psychometric properties. Materials and methods: Forward and backward translation was executed according to official guidelines. The final version of the FAOS was investigated in 150 patients with various foot and ankle disorders. All patients completed the FAOS, Short Form-36, numeric rating scales for pain and disability, and the Hannover questionnaire. The FAOS was re-administered after 1 week. Test-retest reliability, internal consistency, minimal detectable change, construct validity, and floor and ceiling effects were analyzed. Results: Test-retest reliability and internal consistency of each subscale were excellent (intraclass correlation coefficient, 0.88-0.95; Cronbach's α, 0.94-0.98). The minimal detectable changes of each subscale were 17.1-20.8 at the individual level and 2.0-2.4 at group level. There were moderate to strong correlations between FAOS subscales and physical outcomes and low to moderate correlations between FAOS subscales and mental outcomes. Floor and ceiling effects were not present. Conclusion: The German version of the FAOS is a reliable and valid instrument for use in foot and ankle patients. [ABSTRACT FROM AUTHOR]

Prostheses with single radius (SR) design were supposed to be as good as the physiological kinematic and stability of the knee. This in-vitro biomechanical study compared SR to a multiple radius (MR) design on the one hand and seven left human knee specimens were used. The SR and MR knee prosthesis where implanted with a navigation system. We measured varus/valgus deviation of the mechanical axis and the deviation of the joint-line to the epicondyle-line in different knee flexion degrees (0°, 30°, 45°, 60° and 90°) with and without 15 Nm of varus and valgus stress. Without varus/valgus-stress in all three groups (physiological knee, SR and MR prosthesis) the results were located on the varus-site. The variation of the SR was less than the MR, without being significant. Under varus and valgus stress varus/valgus axis deviation constantly grew. From 0-60° no significant deviation between the two prosthesis models was found. At 90° flexion varus/valgus deviation with the SR component was significantly (p &les; 0.05) smaller compared to the MR design. This in-vitro study showed that the SR prosthesis is significantly more stable in the coronal plane than the MR in higher flexion degrees. This could have an improved effect on biomechanical stability with a higher clinical function after SR-TKA. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the influence of continuous perfusion and mechanical stimulation on bone marrow stromal cells seeded on a collagen meniscus implant. Methods: Bone marrow aspirates from 6 donors were amplified in vitro. 10 human BMSC were distributed on a collagen meniscus implant. Scaffolds were cultured under static conditions (control) or placed into a bioreactor system where continuous perfusion (10 ml/min) or perfusion and mechanical stimulation (8 h of 10% cyclic compression at 0.5 Hz) were administered daily. After 24 h, 7 and 14 days, cell proliferation, synthesis of procollagen I and III peptide (PIP, PIIIP), histology, and the equilibrium modulus of the constructs were analyzed. Results: Proliferation demonstrated a significant increase over time in all groups ( p < 0.001). PIP synthesis was found to increase from 0.1 ± 0.0 U/ml/g protein after 24 h to 2.0 ± 0.5 (perfusion), 3.8 ± 0.3 (mechanical stimulation), and 1.8 ± 0.2 U/ml/g protein (static control, lower than perfusion and mechanical stimulation, p < 0.05). These differences were also evident after 2 weeks (2.7 ± 0.3, 4.0 ± 0.6, and 1.8 ± 0.2 U/ml/g protein, p < 0.01); PIIIP synthesis was found to increase from 0.1 ± 0.0 U/ml/g protein after 24 h to 2.9 ± 0.7 (perfusion), 3.1 ± 0.9 (mechanical stimulation), and 1.6 ± 0.3 U/ml/g protein (controls) after 1 week and remained significantly elevated under the influence of perfusion and mechanical stimulation ( p < 0.01) after 2 weeks. Mechanical stimulation increased the equilibrium modulus more than static culture and perfusion after 2 weeks (24.7 ± 7.6; 12.3 ± 3.7; 15.4 ± 2.6 kPa; p < 0.02). Conclusion: Biomechanical stimulation and perfusion have impact on collagen scaffolds seeded with BMSCs. Cell proliferation can be enhanced using continuous perfusion and differentiation is fostered by mechanical stimulation. Level of evidence: Non-applicable experimental study. [ABSTRACT FROM AUTHOR]

We present a 532 nm-pumped singly-resonant cw optical parametric oscillator based on MgO-doped PPLN with a minimum threshold pump power of 0.3 W. The OPO with a two-mirror standing-wave cavity is optimized by using a tunable diode laser on the path of the resonant signal beam. The maximum output power is 200 mW at an idler wavelength near 1330 nm at a pump power of 2 W. We report the degradation of the output power and beam characteristics at high pump power indicating a strong thermal lensing in the crystal. The continuous tuning range of the OPO is measured to be 800 MHz which is close to 90% of the free spectral range of the OPO cavity. [ABSTRACT FROM AUTHOR]

We present a diode laser pumped continuous wave, pump-enhanced singly-resonant optical parametric oscillator (OPO). The cavity is stabilized by a Pound-Drever-Hall scheme using direct modulation of the diode laser. The system provides stable signal powers of up to 220 mW. The wavelength can be tuned between 1.40-1.60 μm for a ring or a linear cavity design by changing the crystal temperature. The relative fluctuations of the stabilized OPO's wavelength are less than 10 for more than one hour. Using a self-heterodyne technique, we measure a linewidth of the signal wave of 3.5 MHz. [ABSTRACT FROM AUTHOR]

We present investigations on single Ni/Si related color centers produced via ion implantation into single crystalline type IIa CVD diamond. By testing different ion dose combinations we show that there is an upper limit for both the Ni and the Si dose (10 cm and 10 cm resp.) due to the creation of excess fluorescent background. We demonstrate creation of Ni/Si related centers showing emission in the spectral range between 767 nm and 775 nm and narrow line-widths of ≈2 nm FWHM at room temperature. Measurements of the intensity autocorrelation functions prove single-photon emission. The investigated color centers can be coarsely divided into two groups: Drawing from photon statistics and the degree of polarization in excitation and emission, we find that some color centers behave as two-level, single-dipole systems whereas other centers exhibit three levels and contributions from two orthogonal dipoles. In addition, some color centers feature stable and bright emission with saturation count rates up to 78 kcounts/s whereas others show fluctuating count rates and three-level blinking. [ABSTRACT FROM AUTHOR]

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We report on a green-pumped continuous-wave singly resonant optical parametric oscillator (cw SRO) based on MgO-doped periodically poled LiNbO3. Operating the SRO at crystal temperatures between 40.0°C to 80.0°C an idler wavelength range of 1406–1451 nm can be accessed. The system provides stable single-frequency idler radiation of more than 300 mW at a pump power of 2 W while featuring a low threshold (<1.2 W). Above a pump power of 2.1 W we observe multimode operation, which is similar to the behavior reported for infrared-pumped SROs. To show the applicability of the device we demonstrate Doppler-free saturation spectroscopy of the cesium D2 line using the signal wave and frequency stabilization to a crossover resonance of the D2 transition. [ABSTRACT FROM AUTHOR]

Time-resolved light-induced birefringence measurements based on a phase compensation technique are used to determine the charge transport properties of congruent, nominally-undoped lithium niobate crystals (LiNbO3). Some of the crystals are conventionally oxidized. The steady-state space-charge field Epv, the bulk photovoltaic coefficient β, and the photoconductivity σph are determined in the intensity range (30–30 000) W/cm2. The photovoltaic coefficient β increases by one order of magnitude over this intensity range, the space-charge field Epv even by two orders of magnitude. We discuss the results in the context of the known one- and two-center charge transport models for LiNbO3. The experimental findings presented here are of relevance for the long-standing problem of optical damage in such crystals, which inhibits their use in high-intensity applications like nonlinear optics. [ABSTRACT FROM AUTHOR]

We describe an ion-based cavity-QED system in which the internal dynamics of an atom is coupled to the modes of an optical cavity by vacuum-stimulated Raman transitions. We observe Raman spectra for different excitation polarizations and find quantitative agreement with theoretical simulations. Residual motion of the ion introduces motional sidebands in the Raman spectrum and leads to ion delocalization. The system offers prospects for cavity-assisted resolved-sideband ground-state cooling and coherent manipulation of ions and photons. [ABSTRACT FROM AUTHOR]

The generation, manipulation and fundamental understanding of entanglement lies at the very heart of quantum mechanics. Entangled particles are non-interacting but are described by a common wavefunction; consequently, individual particles are not independent of each other and their quantum properties are inextricably interwoven. The intriguing features of entanglement become particularly evident if the particles can be individually controlled and physically separated. However, both the experimental realization and characterization of entanglement become exceedingly difficult for systems with many particles. The main difficulty is to manipulate and detect the quantum state of individual particles as well as to control the interaction between them. So far, entanglement of four ions or five photons has been demonstrated experimentally. The creation of scalable multiparticle entanglement demands a non-exponential scaling of resources with particle number. Among the various kinds of entangled states, the ‘W state’ plays an important role as its entanglement is maximally persistent and robust even under particle loss. Such states are central as a resource in quantum information processing and multiparty quantum communication. Here we report the scalable and deterministic generation of four-, five-, six-, seven- and eight-particle entangled states of the W type with trapped ions. We obtain the maximum possible information on these states by performing full characterization via state tomography, using individual control and detection of the ions. A detailed analysis proves that the entanglement is genuine. The availability of such multiparticle entangled states, together with full information in the form of their density matrices, creates a test-bed for theoretical studies of multiparticle entanglement. Independently, ‘Greenberger–Horne–Zeilinger’ entangled states with up to six ions have been created and analysed in Boulder. [ABSTRACT FROM AUTHOR]

The scheme of an ion trap quantum computer is described and the implementation of quantum gate operations with trapped Ca+ ions is discussed. Quantum information processing with Ca+ ions is exemplified with several recent experiments investigating entanglement of ions. PACS: 03.67.Lx, 03.67.Mn, 32.80.Pj [ABSTRACT FROM AUTHOR]

Teleportation of a quantum state encompasses the complete transfer of information from one particle to another. The complete specification of the quantum state of a system generally requires an infinite amount of information, even for simple two-level systems (qubits). Moreover, the principles of quantum mechanics dictate that any measurement on a system immediately alters its state, while yielding at most one bit of information. The transfer of a state from one system to another (by performing measurements on the first and operations on the second) might therefore appear impossible. However, it has been shown that the entangling properties of quantum mechanics, in combination with classical communication, allow quantum-state teleportation to be performed. Teleportation using pairs of entangled photons has been demonstrated, but such techniques are probabilistic, requiring post-selection of measured photons. Here, we report deterministic quantum-state teleportation between a pair of trapped calcium ions. Following closely the original proposal, we create a highly entangled pair of ions and perform a complete Bell-state measurement involving one ion from this pair and a third source ion. State reconstruction conditioned on this measurement is then performed on the other half of the entangled pair. The measured fidelity is 75%, demonstrating unequivocally the quantum nature of the process. [ABSTRACT FROM AUTHOR]

Copyright of Der Unfallchirurg is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We report the realization of an elementary quantum processor based on a linear crystal of trapped ions. Each ion serves as a quantum bit (qubit) to store the quantum information in long lived electronic states. We present the realization of single-qubit and of universal two-qubit logic gates. The two-qubit operation relies on the coupling of the ions through their collective quantized motion. A detailed description of the setup and the methods is included. [ABSTRACT FROM AUTHOR]

We present a scheme for employing a violet extended-cavity diode laser in experiments with single, trapped ions. For this the grating-stabilised laser is spatially and spectrally filtered and referenced to a Fabry-Pérot cavity. We measure an upper limit to the line width by observing a 305-kHz FWHM beat note with the second harmonic of a titanium sapphire laser. The laser is subsequently used to optically cool a single [SUP40]Ca[SUP+] ion close to the Doppler limit. [ABSTRACT FROM AUTHOR]

We demonstrate coherent coupling of the quadrupole S[sub 1/2] &hoarr;D[sub 5/2] optical transition of a single trapped [sup 40] Ca[sup +] ion to the standing wave field of a high-finesse cavity. The dependence of the coupling on temporal dynamics and spatial variations of the intracavity field is investigated in detail. By precisely controlling the position of the ion in the cavity standing wave field and by selectively exciting vibrational state-changing transitions the ion’s quantized vibration in the trap is deterministically coupled to the cavity mode. We confirm coherent interaction of ion and cavity field by exciting Rabi oscillations with short resonant laser pulses injected into the cavity, which is frequency-stabilized to the atomic transition. [ABSTRACT FROM AUTHOR]

We report on the production of nanodiamonds (NDs) with 70-80 nm size via bead assisted sonic disintegration (BASD) of a polycrystalline chemical vapor deposition film. The high crystalline quality NDs display intense narrowband (7 nm) room temperature luminescence at 738 nm from in situ incorporated silicon vacancy centers. We demonstrate bright, narrowband single photon emission with >100 000 cps. Due to the narrow fluorescence bandwidth as well as the near-infrared emission these NDs are also suitable as fluorescence labels with significantly enhanced performance for in vivo imaging. [ABSTRACT FROM AUTHOR]

It is common belief among physicists that entangled states of quantum systems lose their coherence rather quickly. The reason is that any interaction with the environment which distinguishes between the entangled sub-systems collapses the quantum state. Here we investigate entangled states of two trapped Ca+ ions and observe robust entanglement lasting for more than 20 s. [ABSTRACT FROM AUTHOR]

We investigate cavity-quantum electrodynamics (QED) effects in an all-semiconductor nanostructure by tuning a single self-assembled InAs quantum dot (QD) into resonance with a high quality factor microdisk whispering gallery mode (WGM). The stronger temperature dependence of the QD single-exciton (1X) resonance allows us to change the relative energy of the WGM and the 1X transitions by varying the sample temperature. The two coupled resonances exhibit crossing behavior due to the weak coupling cavity-QED regime. We demonstrate exciton lifetime reduction by 6 due to the Purcell effect by tuning the QD into resonance with the WGM. Our experiments also show that single-exciton lifetime is independent of temperature up to 50 K. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We report the use of self-assembled InAs quantum dots as active emitters in a photonic crystal microcavity. We have fabricated defect microcavities by removing 37 and 61 air holes from a triangular lattice in a photonic crystal membrane, and obtained quality factors in excess of 1000. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]