Explore the vast range of titles available.

The estimation of low energies of many-body systems is a cornerstone of the computational quantum sciences. Variational quantum algorithms can be used to prepare ground states on pre-fault-tolerant quantum processors, but their lack of convergence guarantees and impractical number of cost function estimations prevent systematic scaling of experiments to large systems. Alternatives to variational approaches are needed for large-scale experiments on pre-fault-tolerant devices. Here, we use a superconducting quantum processor to compute eigenenergies of quantum many-body systems on two-dimensional lattices of up to 56 sites, using the Krylov quantum diagonalization algorithm, an analog of the well-known classical diagonalization technique. We construct subspaces of the many-body Hilbert space using Trotterized unitary evolutions executed on the quantum processor, and classically diagonalize many-body interacting Hamiltonians within those subspaces. These experiments demonstrate exponential convergence towards an estimate of the ground state energy, and show that quantum diagonalization algorithms are poised to complement their classical counterparts at the foundation of computational methods for quantum systems. The estimation of low energies of many-body systems is a cornerstone of the computational quantum sciences. This paper demonstrates on a superconducting quantum processor that the Krylov quantum diagonalization algorithm is poised to complement its classical counterparts at the foundation of computational methods for quantum systems.

In the field of quantum control, effective Hamiltonian engineering is a powerful tool that utilizes perturbation theory to mitigate or enhance the effect that a variation in the Hamiltonian has on the evolution of the system. Here, we provide a general framework for computing arbitrary time-dependent perturbation theory terms, as well as their gradients with respect to control variations, enabling the use of gradient methods for optimizing these terms. In particular, we show that effective Hamiltonian engineering is an instance of a bilinear control problem-the same general problem class as that of standard unitary design-and hence the same optimization algorithms apply. We demonstrate this method in various examples, including decoupling, recoupling, and robustness to control errors and stochastic errors. We also present a control engineering example that was used in experiment, demonstrating the practical feasibility of this approach.

We present a new method for high-resolution nanoscale magnetic resonance imaging (nano-MRI) that combines the high spin sensitivity of nanowire-based magnetic resonance detection with high-spectral-resolution nuclear magnetic resonance (NMR) spectroscopy. Using a new method that incorporates average Hamiltonian theory into optimal control pulse engineering, we demonstrate NMR pulses that achieve high-fidelity quantum control of nuclear spins in nanometer-scale ensembles. We apply this capability to perform dynamical decoupling experiments that achieve a factor of 500 reduction of the proton-spin resonance linewidth in a(50−nm)3volume of polystyrene. We make use of the enhanced spin coherence times to perform Fourier-transform imaging of proton spins with a one-dimensional slice thickness below 2 nm.

Background There are different procedures for both, the diagnosis and the therapy of a periprosthetic joint infection (PJI), however, national or international guidelines for a standardised treatment regime are still lacking. The present paper evaluates the use of the predominant treatment protocols for PJI in certified total joint replacement centres (EPZ) in Germany based on an EndoCert questionnaire. Materials and methods The questionnaire was developed in cooperation with the EndoCert Certification Commission to survey the treatment protocols for septic revision arthroplasties in EPZ. Questions targeted the various treatment options including prosthesis preserving procedures (DAIR - Debridement, antibiotics, irrigation, and retention of the prosthesis), one-stage revision, two-stage revision, removal of the endoprosthesis and diagnostic sampling prior to re-implantation. All certified EPZ participated ( n  = 504) and the results from the current survey in 2020 were compared to data from a previous analysis in 2015. Results The number of centres that performed DAIR up to a maximum of 4 weeks and more than 10 weeks after index surgery decreased since 2015, while the number of centres that provided a one-stage revision as a treatment option increased (hip: + 6.3%; knee: + 6.6%). The majority of the centres (73.2%) indicated a 4–8 week period as the preferred interval between prosthesis removal and re-implantation in two-stage revision in hip as well as knee revisions. Centres with a higher number of revision surgeries (> 200 revisions/year), opted even more often for the 4–8 week period (92.3%). In two-stage revision the use of metal-based spacers with/without reinforcement with antibiotic-containing cement as an interim placeholder was significantly reduced in 2020 compared to 2015. There was also a clear preference for cemented anchoring in two-stage revision arthroplasty in the knee in 2020, whereas the majority of hip replacements was cementless. Additionally, in 2020 the number of samples for microbiological testing during the removal of the infected endoprosthesis increased and 72% of the centres took five or more samples. Overall, the number of EPZ with a standardised protocol for the procedure expanded from 2015 to 2020. Conclusion While there was a trend towards standardised therapeutic algorithms for PJI with more uniform choices among the centres in 2020 compared to 2015, the treatment often remains an individual decision. However, since a consistent treatment regime is of vital importance with an expected rise of total numbers of revision arthroplasties, uniform definitions with regard to comparability and standardisation are necessary for the further development of the EndoCert system.

Background The periprosthetic joint infection (PJI) is a severe complication in the field of arthroplasty. Despite the rising number of primary joint replacements, no unified therapeutic standard has been established for the treatment of PJI yet. Methods A survey on the principles of treatment of PJI in Germany was conducted. A total of 515 EndoProthetikZentren (EPZ) were included, resulting in a response rate of 100%. Results For early infections 97.6% of the centers use prosthesis-preserving procedures (DAIR). A one-stage exchange was implemented by less than 50% of the centers. If implemented, this treatment entails a prior selection of patients for a successful treatment. The two-stage exchange is performed in all centers, and most centers proceed with the implantation of a cemented spacer between stages. 75% of the centers proceed with a center-based concept for the treatment of PJI. Conclusion The aim of a uniform PJI standard at the centers has not yet been fully achieved. Further improvements within the certification were initiated. The most relevant treatment options in Germany are displayed. The two-stage revision with a cemented spacer is the most widely implemented treatment. This exposition of principles could help for the further development of standardized treatment guidelines and definitions.

Background Osteoarthritis (OA) is one of the most common disabilities in the elderly. When conservative management fails, total joint arthroplasty (TJA) is the treatment of choice for end-stage OA. Since quality and durability of implants has steadily improved, pre -and postsurgical processes moved into the focus of research. Hence, eHealth approaches offer an opportunity to provide a more available continuity of care. Regarding individualized pre-, peri-, and postsurgical stages, eHealth is expected to improve patient engagement, self-care, and outcomes across the surgical pathway. Aim of this study is to evaluate the effectiveness of the eHealth application “alley” as an adjuvant intervention to TJA. The app provides comprehensive information to empower patient with hip or knee OA to prepare and accompany them for their TJA surgery. Our primary hypothesis is that the pre- and postoperative adjuvant use of the eHealth application “alley” (intervention group, IG) leads to improved functional outcome. Methods Prospective, randomized, controlled, multi-center trial including n  = 200 patients diagnosed with hip and n  = 200 patients with knee OA ( n  = 200) scheduled for TJA. Patients of both groups will be randomly assigned to one of two study arms. Patients in the intervention group will receive access to the functions of the “alley” app. The app presents informative (e.g., information about osteoarthritis), organizational (e.g., information about medical rehabilitation), and emotional/empowerment (e.g., information about the relationship between mood and pain) content. Patients evaluate their condition and functional level by means of standardized digitally questionnaires. Patients in the control group will not receive any functions of the app. Assessments will be performed at baseline before, 10 days after, 1 months after, 3 months after, 6 months after, and 12 months after TJA. Primary outcome is change from baseline measured by the Hip Osteoarthritis Outcome Score or Knee injury and Osteoarthritis Outcome Score 3 months after TJA. The statistical analysis ( t -test for independent variables with effect size Cohen’s d ) is performed separately for patients with TKA and THA. Discussion Overall, the study aims to improve the understanding of the benefits of eHealth applications in the treatment of elderly patients with knee or hip arthroplasty. The approach is novel since a health care companion is combined with a digital information platform enabling direct and continuous feedback from the patients to the therapeutic treatment team. As the study investigate the effectiveness under everyday conditions, it is not feasible to control whether the patients in the IG read the educational information of the app respectively the control group consume additional information from other sources. However, this increases the external validity of the study if significant effects for the app can be demonstrated. Trial registration German Clinical Trials Register: DRKS00025608. Registered on 21 June 2021.

We have combined ultrasensitive force-based spin detection with high-fidelity spin control to achieve NMR diffraction (NMRd) measurement of ~2 million 31P spins in a (50 nm)³ volume of an indium-phosphide (InP) nanowire. NMRd is a technique originally proposed for studying the structure of periodic arrangements of spins, with complete access to the spectroscopic capabilities of NMR. We describe two experiments that realize NMRd detection with subangstrom precision. In the first experiment, we encode a nanometer-scale spatial modulation of the z -axis magnetization of 31P spins and detect the period and position of the modulation with a precision of <0.8 Å. In the second experiment, we demonstrate an interferometric technique, utilizing NMRd, to detect an angstrom-scale displacement of the InP sample with a precision of 0.07 Å. The diffraction-based techniques developed in this work extend the Fourier-encoding capabilities of NMR to the angstrom scale and demonstrate the potential of NMRd as a tool for probing the structure and dynamics of nanocrystalline materials.

The EndoCert initiative does not yet allow a long-term assessment of outcome quality. The assessment cannot be achieved without cooperation with the German arthroplasty registry (EPRD) and other quality assurance infrastructure, such as the quality assurance system of the nationwide healthcare insurance data for inpatient hospital treatment (QSR) by the German local healthcare fund (AOK). Therefore, the quality of care of all certified centres for joint replacement (EPZ) after primary hip and knee arthroplasty was to be examined for the first time. These data were subsequently compared to the data of the EPRD. In EPZ that provided care to at least one AOK-insured patient in 2016, the risk-adjusted 3‑year revision rate and the SMR-value (standardised mortality or morbidity ratio), which is the quotient of the observed and expected revision rate, were analysed as markers for the quality of care. Annual hospital volume, type of centre and audit results were examined as possible influencing factors. In the group comparison, significant differences (p = 0.042) for the SMR value of the 3‑year revision rate were demonstrated for hip arthroplasty with regard to the EPZ type. The annual number of primary hip arthroplasties, however, did not influence the 3‑year revision rate. For knee arthroplasties, no effect of the defined categories on the 3‑year revision rate and its SMR value was observed. The comparison of our 3‑year revision rates with those of the EPRD showed similar results for the hip but indicated significant differences for the knee. We did not observe a correlation between quality of care and annual hospital volume in certified EPZ. However, different quality assurance procedures can lead to different results with respect to the outcome quality. Therefore, a considerably improved interaction of the German quality systems must be achieved. Participation in the EPRD is not sufficient for this. Rather, a complete report of all arthroplasties must be required, at least with the achievement of a minimum reporting rate per participating hospital. Uniform inclusion and exclusion criteria should be defined.

Zusammenfassung Hintergrund Eine langfristige Beurteilung der Ergebnisqualität lässt das EndoCert-Verfahren bisher nicht zu und kann ohne Kooperationen mit dem Endoprothesenregister Deutschland (EPRD) oder anderen Qualitätssicherungsverfahren, wie dem Qualitätssicherungssystem mit Routinedaten der AOK (QSR) auch nicht erreicht werden. Es soll erstmalig unter Einbeziehung von QSR-Daten der AOK die Versorgungsqualität aller zertifizierten Zentren (EPZ) nach primärer Hüft- und Knie-TEP (Totalendoprothese) geprüft und mit den Daten des EPRD verglichen werden. Material und Methoden In EPZ, die mindestens eine/-n AOK-Versicherte/-n im Jahr 2016 versorgt haben, wurden die risikoadjustierte 3‑Jahres-Revisionsrate und der SMR-Wert (standardisierte Mortalitäts‑/Morbiditätsratio), welcher der Quotient aus beobachteter und erwarteter Revisionsrate ist, als Marker für die Versorgungsqualität analysiert. Versorgungshäufigkeit, Zentrumsart und Auditergebnisse wurden als Einflussfaktoren untersucht. Ergebnisse Beim Gruppenvergleich wurden für die Hüft-TEP hinsichtlich der EPZ-Art signifikante Unterschiede ( p  = 0,042) für den SMR-Wert der 3‑Jahres-Revisionsrate nachgewiesen. Die Anzahl der primären Hüft-TEP hatte hingegen keinen Einfluss auf die 3‑Jahres-Revisionsrate. Für die Knie-TEP wurde kein Effekt der definierten Kategorien auf die 3‑Jahres-Revisionsrate und deren SMR-Wert beobachtet. Die Gegenüberstellung unserer 3‑Jahres-Revisionsraten mit denen vom EPRD zeigte vergleichbare Ergebnisse bei Hüft-TEP, jedoch erhebliche Unterschiede bei Knie-TEP. Diskussion Wir konnten keinen Zusammenhang zwischen Versorgungsqualität und -häufigkeit in den EPZ nachweisen. Allerdings können unterschiedliche QS-Verfahren zu abweichenden Bewertungen der Ergebnisqualität führen. Eine deutlich bessere Vernetzung der Systeme sollte angestrebt werden. Dafür ist die Teilnahme am EPRD nicht ausreichend. Vielmehr muss eine vollständige Eingabe aller Prothesenversorgungen, zumindest unter Erreichung einer Mindestquote je teilnehmender Klinik, gefordert werden. Einheitliche Ein- und Ausschlusskriterien sollten definiert werden.

HintergrundEine langfristige Beurteilung der Ergebnisqualität lässt das EndoCert-Verfahren bisher nicht zu und kann ohne Kooperationen mit dem Endoprothesenregister Deutschland (EPRD) oder anderen Qualitätssicherungsverfahren, wie dem Qualitätssicherungssystem mit Routinedaten der AOK (QSR) auch nicht erreicht werden. Es soll erstmalig unter Einbeziehung von QSR-Daten der AOK die Versorgungsqualität aller zertifizierten Zentren (EPZ) nach primärer Hüft- und Knie-TEP (Totalendoprothese) geprüft und mit den Daten des EPRD verglichen werden.Material und MethodenIn EPZ, die mindestens eine/-n AOK-Versicherte/-n im Jahr 2016 versorgt haben, wurden die risikoadjustierte 3‑Jahres-Revisionsrate und der SMR-Wert (standardisierte Mortalitäts‑/Morbiditätsratio), welcher der Quotient aus beobachteter und erwarteter Revisionsrate ist, als Marker für die Versorgungsqualität analysiert. Versorgungshäufigkeit, Zentrumsart und Auditergebnisse wurden als Einflussfaktoren untersucht.ErgebnisseBeim Gruppenvergleich wurden für die Hüft-TEP hinsichtlich der EPZ-Art signifikante Unterschiede (p = 0,042) für den SMR-Wert der 3‑Jahres-Revisionsrate nachgewiesen. Die Anzahl der primären Hüft-TEP hatte hingegen keinen Einfluss auf die 3‑Jahres-Revisionsrate. Für die Knie-TEP wurde kein Effekt der definierten Kategorien auf die 3‑Jahres-Revisionsrate und deren SMR-Wert beobachtet. Die Gegenüberstellung unserer 3‑Jahres-Revisionsraten mit denen vom EPRD zeigte vergleichbare Ergebnisse bei Hüft-TEP, jedoch erhebliche Unterschiede bei Knie-TEP.DiskussionWir konnten keinen Zusammenhang zwischen Versorgungsqualität und -häufigkeit in den EPZ nachweisen. Allerdings können unterschiedliche QS-Verfahren zu abweichenden Bewertungen der Ergebnisqualität führen. Eine deutlich bessere Vernetzung der Systeme sollte angestrebt werden. Dafür ist die Teilnahme am EPRD nicht ausreichend. Vielmehr muss eine vollständige Eingabe aller Prothesenversorgungen, zumindest unter Erreichung einer Mindestquote je teilnehmender Klinik, gefordert werden. Einheitliche Ein- und Ausschlusskriterien sollten definiert werden.