Dynamics of magnetization at infinite temperature in a Heisenberg spin chain.

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Stable quantum-correlated many-body states through engineered dissipation.

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Formation of robust bound states of interacting microwave photons.

Systems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles1. The lack of general solutions for the three-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multiparticle bound states2-9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five photons. We devise a phase-sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the idea that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit.

[The underrepresentation of complex patient groups in scientific research: ethical considerations]. / De ondervertegenwoordiging van complexe patiëntengroepen in wetenschappelijk onderzoek: ethische overwegingen.

BACKGROUND: Subgroups of patients with severe mental illness are underrepresented in scientific research. One of the possible causes is the fact that in these patient groups barriers may exist to the giving of competent informed consent. AIM: Describing the ethical dilemmas that may occur when conducting research with these patient groups. METHOD: We present an overview of the Dutch legislation and regulation concerning participation in scientific research, and discuss the ethical dilemmas that arise in the mentioned patient groups. We present four directions for solutions. RESULTS: In research with these patient groups more attention is needed for the explicit assessment and enhancement of competence. For the subgroup that is persistently incompetent, the possibilities of doing research with existing patient data without informed consent, need further exploration. CONCLUSION: Further legislative development is needed for research with patients with severe mental illness who are persistently incompetent. Herein, it is crucial to involve ethicists and organizations representing patients' and relatives' perspectives.

Variety in diagnosis and treatment of periprosthetic joint infections in Belgium and the Netherlands.

Recently, guidelines regarding diagnosis and treatment of periprosthetic joint infection (PJI) have been published, but it is unknown how well these are -followed in the Netherlands and Belgium. Therefore, a survey study was performed in the Netherlands and Belgium. 81 orthopedic departments responded (54% in the Netherlands, 52% in Belgium). The majority used protocols for antibiotic and surgical treatment. To discriminate between early and late infection, differences in periods used were seen between respondents, and between countries. Empirical antibiotic treatment varied greatly. Debridement, antibiotics, irrigation and retention of the prosthesis (DAIR) is the -almost unanimous treatment of choice for early PJI. Guidelines are available, but seem not (yet) to be -followed accurately, and do not have answers to all possible treatment options. Perhaps, national guidelines might produce more standardized care, and -consequentially, easier comparison for research, more transparency for patients, and less health care costs.

[Compulsory abstinence: integrated treatment measure of schizophrenia combined with comorbid substance abuse]. / Duwen richting abstinentie: toepassing van drang en dwang bij schizofrenie met comorbide middelenafhankelijkheid.

Schizophrenia accompanied by comorbid substance use disorder is common and can complicate treatment. For the patient long-term compulsory abstinence can be seen as an extremely serious measure. Nevertheless, the measure can be justified both ethically and juridically as part of integrated treatment for psychosis and substance use disorder. We describe a case in which long-term compulsory abstinence kept the patient out of danger, increased her psychiatric stability and strengthened her autonomy.

[Complications after supra-aortic reconstruction]. / Komplikationen nach supraaortaler Rekonstruktion.

BACKGROUND: Surgical interventions on the supra-aortic vessels are common procedures to avoid cerebral ischemia or arm pain during exercise. The safety and efficacy has been confirmed by clinical studies. Complications are rare but have serious consequences. OBJECTIVES: What special indications and recommendations are there for the diagnostics and treatment in the perioperative phase? METHODS: The current article is a literature-based review that considers international studies, guidelines and personal experiences. RESULTS: There is a broad range of complications. A simple systematic physical examination is often sufficient to give indications of the problem. Confirming clinical apparative examinations are mostly intraoperative angiography or sonography, whereas postoperative procedures include color-coded duplex sonography (FKDS) and angiography computed tomography (angio-CT). Important basic principles and aspects of operative procedures are presented. Evidence-based differences between the treatment options with resulting complications are mostly unknown; therefore, clinical management mostly relies on expert recommendations. CONCLUSION: There are several modern treatment options for invasive therapy. Despite a decrease in previous complication rates, typical perioperative complications must be considered. The diagnosis and therapy is carried out according to established strategies.

[Venous Aneurysms of the Lower Extremities - Clinical Significance and Therapy]. / Klinische Bedeutung und Therapie venöser Aneurysmen der unteren Extremitäten.

Isolated venous aneurysms are very rare. In clinical practice it is predominantly seen in the course of a random diagnosis to find the cause of pulmonary embolism or venous thrombosis. Due to an increased use of duplex scans there is also an increase in the number of diagnoses of venous aneurysms even if patients are still asymptomatic. The precise prevalence is yet unknown. The choice of therapeutic procedure is dependent on each individual clinic as well as the size and morphology (fusiform or saccular) of the aneurysm. At present, the available data are still insufficient. We discuss our own surgical treatment of 7 patients with primary aneurysms involving the vena cava, iliac vein, great saphenous vein junction and popliteal vein in consideration of the latest literature.

Selective regional perfusion of the bilateral external carotid arteries with pegylated liposomal doxorubicin and melphalan to treat metastatic malignant melanoma of the scalp.

We present the case of a 79-year-old patient with extensive metastatic malignant melanoma (MM) of the scalp. Cutaneous MM of the head and neck often presents a therapeutic challenge. Radical surgical procedures and conventional chemotherapy are often unfeasible and contraindicated because of the difficult anatomy, the extent of the tumour process, and systemic toxicity. In our patient, selective intra-arterial perfusion with pegylated liposomal doxorubicin (PLD) and melphalan was performed after catheterization of both bilateral external carotid arteries with an arterial port system. PLD 4.5 mg/m(2) and melphalan (1.35 mg/m(2), followed by 2.7 mg/m(2) after reaching tolerance) were given as short-term infusions at two-weekly intervals into the right and left external carotid arteries, respectively. After eight applications with tolerable side-effects, no MM cells were detected; however, infiltrates of lymphocytes and melanophages were seen. This case suggests that intra-arterial chemotherapy may be a useful treatment for metastatic melanoma of the scalp.

["Your child is hard of hearing" - a longitudinal study of parental distress]. / "Ihr Kind ist schwerhörig" - Eine Verlaufsuntersuchung zum elterlichen Befinden.

BACKGROUND: In models, hearing impairment in children is linked to parental distress. Empiric data about coping with this stress is small, however, as there are virtually only cross section studies which we can refer to. METHODS: 124 mothers and fathers of 61 children with a hearing impairment, who had their first hearing aid fitted respectively, had been presented to the pre-examination for a Cochlear Implantation (CI). Over a period of two years five respectively six measurements of their psycho-social distress were taken. In addition, the speech status of the children was evaluated. RESULTS: Shortly after the diagnosis and before implantation parental quality of life is significantly reduced. Enduring parental distress could not be established. However, particularly when the CI-indication is unclear parents were found to be negatively affected in their well-being. Social support and positive self-awareness were found to moderate parental distress. CONCLUSIONS: The significant reduction of parental quality of life at the onset of the treatment would indicates the need of special psychological support of the parents in this phase. The stabilisation of the parents' well-being over the course of the treatment signifies that a "normal every day life" can be attained for affected families despite the impairment.

[Münchner screening of auditory perception disorders (MAUS)]. / Münchner Auditiver Screeningtest für Verarbeitungs- und Wahrnehmungsstörungen (MAUS).

BACKGROUND: The diagnosis of APD (Auditory Perception Disorder) is a time consuming procedure. In Germany at the present, no screening test for APD exists which makes it possible to differentiate between children who are not likely to suffer from an APD and those who need to be diagnosed in detail. METHOD: The Munich Auditory Screening of Perception Disorders (MAUS) contains the following subtests: Series of Syllables, Words in Noise and Identification and Differentiation of Phonemes (test duration: 15 minutes). PATIENTS: The MAUS was standardized using 359 primary school children between 6 and 11 years of age. Furthermore, the MAUS was used in addition to the complete, extensive APD-diagnostics in testing 52 children (36 with APD and 16 without APD) within the age group mentioned. RESULTS: T-scores for each subtest were established by the standardization of the MAUS. The internal consistency of the test was sufficient. The intercorrelation between subtests was very slight. Therefore, each subtest seems to play an independent part in defining the construct of APD. Because of the results of the pilot study which formed the basis for the development of the screening instrument used, and because of the sensitivity scores reached in testing a group of 36 children with diagnosed APD, it can be expected that the MAUS will show a high sensitivity with regard to APD. CONCLUSION: Using the MAUS, it can be determined if and to what extent the test results of an individual deviate from those of the normal primary school population. The MAUS can identify children at risk of having an APD and can differentiate these children from those who are unlikely to suffer from an APD.

[Multicentric extra-abdominal fibromatosis: a rare case]. / Multizentrische extraabdominale Fibromatose -- ein seltener Fall.

Extra-abdominal aggressive fibromatosis is a benign fibroblastic neoplasia with an infiltrative nature and a high tendency of local recurrence. Here, we report on a very rare case of multicentric fibromatosis. Low complaints led to considerable size of the tumours. The aim of the multimodal treatment was a limb salvage procedure. Adjuvant radiation therapy and chemotherapy was necessary because of the renunciation of wide resections in favour of the functionality of the limb.

Evaluation of target scores and benchmarks for the traversal task scenario of the Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) laparoscopy simulator.

BACKGROUND: The Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) simulator is validated for laparoscopy training, but benchmarks and target scores for assessing single tasks are needed. METHODS: Control data for the MIST-VR traversal task scenario were collected from 61 novices who performed the task 10 times over 3 days (1 h daily). Data were collected on the time taken, error score, economy of movement, and total score. Test differences were analyzed through percentage scores and t-tests for paired samples. RESULTS: Improvement was greatest over tests 1 to 5 (improvement: test(1.2), 38.07%; p = 0.000; test(4.5), 10.66%; p = 0.010): between tests 5 and 10, improvement slowed and scores stabilized. Variation in participants' performance fell steadily over the 10 tests. CONCLUSION: Trainees should perform at least 10 tests of the traversal task-five to get used to the equipment and task (automation phase; target total score, 95.16) and five to stabilize and consolidate performance (test 10 target total score, 74.11).

Distribution of microcystins in a lake foodweb: no evidence for biomagnification.

Microcystins, toxins produced by cyanobacteria, may play a role in fish kills, although their specific contribution remains unclear. A better understanding of the eco-toxicological effects of microcystins is hampered by a lack of analyses at different trophic levels in lake foodwebs. We present 3 years of monitoring data, and directly compare the transfer of microcystin in the foodweb starting with the uptake of (toxic) cyanobacteria by two different filter feeders: the cladoceran Daphnia galeata and the zebra mussel Dreissena polymorpha. Furthermore foodwebs are compared in years in which the colonial cyanobacterium Microcystis aeruginosa or the filamentous cyanobacterium Planktothrix agardhii dominated; there are implications in terms of the types and amount of microcystins produced and in the ingestion of cyanobacteria. Microcystin concentrations in the seston commonly reached levels where harmful effects on zooplankton are to be expected. Likewise, concentrations in zooplankton reached levels where intoxication of fish is likely. The food chain starting with Dreissena (consumed by roach and diving ducks) remained relatively free from microcystins. Liver damage, typical for exposure to microcystins, was observed in a large fraction of the populations of different fish species, although no relation with the amount of microcystin could be established. Microcystin levels were especially high in the livers of planktivorous fish, mainly smelt. This puts piscivorous birds at risk. We found no evidence for biomagnification of microcystins. Concentrations in filter feeders were always much below those in the seston, and yet vectorial transport to higher trophic levels took place. Concentrations of microcystin in smelt liver exceeded those in the diet of these fish, but it is incorrect to compare levels in a selected organ to those in a whole organism (zooplankton). The discussion focuses on the implications of detoxication and covalent binding of microcystin for the transfer of the toxin in the foodweb. It seems likely that microcystins are one, but not the sole, factor involved in fish kills during blooms of cyanobacteria.

[Vena cava filter -- is there an indication for implantation?]. / Kavafilter -- gibt es eine Indikation zur Implantation?

The indication of vena cava filter implantation is controversially discussed. On the basis of the available literature and our own results a critical analysis of this issue is given. Between 1994 and 2003, we inserted a total of 29 vena cava filters; 24 temporary and 5 permanent filters. In twelve patients, the placement of the filter was indicated due to pulmonary embolism and a contra-indication to dose adjusted heparin therapy. Seven additional patients experienced a recurrent pulmonary embolism despite adequate heparin therapy. An additional prophylactic filter insertion was carried out in ten patients. The temporary vena cava filters were left in place between 7 to 38 days with an average of 17 days. Total implantation time of temporary filters was scheduled until complete mobilisation of the patients, generally in conjunction with an effective dosage of oral anticoagulants. No patient died in connection with the insertion of the filter and no further pulmonary embolisms occurred. One case of inferior vena cava thrombosis occurred in each group of temporary and permanent filters. In one third of the removed filter systems, thrombi in the filter were found. Local infections of the catheter and introducer sets were observed in two patients. Moreover, in one case the strut of a temporary filter broke and subsequently dislocated 17 days after insertion. However, there is little evidence concerning vena cava filters, and further investigations are necessary. Until additional data are available, filters should generally be restricted to patients with deep venous thrombosis and pulmonary embolism who cannot receive anticoagulation, and highly selected cases.

[Management of postoperative compartment syndrome -- case report]. / Management des postoperativen lagerungsbedingten Kompartmentsyndroms -- Kasuistik.

AIM: Differential diagnosis and management of the lower extremity compartment syndrome as a potentially devastating complication of prolonged surgery in the lithotomy position. CASE REPORT: A 55-year-old patient underwent radical cystoprostatovesiculourethrectomy including reconstruction of an ileal conduit because of a multifocal recurrent tumor of the urinary bladder (operating time > 8 hours). On the first postoperative day, the patient complained about swelling within the right calf leading to the suspicion of a deep vein thrombosis. Phlebography of the right leg revealed: i) thrombosis-untypical occlusion of the distal popliteal vein and ii) no detection of the deep vein within the right calf (femoral and iliac veins were with no pathological finding). Tissue pressure was as follows: right, 55 mmHg/left, 11 mmHg, underlining clinical suspicion of compartment syndrome. The patient underwent a fasciotomy of the right calf. Over the following 5 days, muscle edema decreased, allowing subsequent mobilization of the patient. On the 8 (th) postoperative day, the patient died unexpectedly due to an acute myocardial infarction. CONCLUSION: In case of a swelling of the lower extremity after long-lasting surgical interventions performed in lithotomy position, a compartment syndrome is one of the possible differential diagnoses, the consequences of which can be avoided by an early diagnostic and adequate treatment.

[Interventional and vascular surgical management for inflammatory arrosion hemorrhage from visceral arteries following pancreatic surgery]. / Entzündliche Arrosionsblutungen aus ViszeralarterienInterventionelles und gefässchirurgisches Management nach vorwiegend pankreaschirurgischen Eingriffen.

Spontaneous or postoperative hemorrhage into the abdominal cavity due to inflammatory vessel arrosion represents an uncommon but menacing situation. According to the literature, such hemorrhage is associated with a lethality of nearly 2%. Therapeutical options include reoperation and interventional radiological techniques such as endovascular catheter techniques with stent graft implantation or the embolization of vessels. We report on the management of seven cases with hemorrhage either from the gastroduodenal artery ( n=5) following pancreatic surgery for pancreatic carcinoma, liposarcoma, and chronic pancreatitis or from the common hepatic artery ( n=1) and the superior mesenteric artery ( n=1) following chronic pancreatitis. The present article describes our experiences with stent graft implantation (hemobahn prosthesis) in four cases. Based on these experiences, we see the advantages of stent grafts in primary hemostasis without any contact to infected tissue and the preservation of regular perfusion. However, further clinical data are required focussing on indication, technical success rates, stent-related complications, and long-term outcome.

[The use of v.a.C.-system in wound management for borderline indications]. / Der Einsatz des V.A.C(R)-Systems im Wundmanagement bei Grenzindikationen.

Vacuum sealing has increasingly become established as a method adapted to treat acute and chronic wounds. Temporary sealing of the open abdomen represents an alternative therapeutic approach. The principle of inverse tissue expansion prevents ventral herniae from developing in the course of delayed abdominal-wall closure. In patients undergoing vascular surgery, the method can be uneventfully adopted in treating chronic ulcer following revascularisation. The accelerated healing process, while reducing the duration of therapy, turns out to be cost-efficient.

[The present state of vacuum sealing]. / Der Stand der Vakuumversiegelung.

In cases of extended post-traumatic soft-tissue and bone loss as well as with mutilating infection or radical tumor resection, multidisciplinary options are required to salvage extremities and functional rehabilitation. A surgical team approach allows for reduction of amputation rates, wound healing complications, and secondary procedures in limb oncology and trauma. The goals and limitations of cooperative surgical concepts are described. In the future, continuing medical education will focus not only on indications and techniques but also on complication management, medicolegal problems, and economic deficits due to maladapted legal structures. Provided clear clinical pathways are introduced to guide indications, surgical procedures, and postoperative treatment, marked financial deficits may be avoided. While, in the past, responsibility for the patient and ethical considerations resulted in the development of voluntary interdisciplinary treatment programs, economic strategies and an increasing number of malpractice suits in the future will inevitably produce new imperatives for interdisciplinary cooperation.

[Adaptive indication in outpatient psychodynamic short-term psychotherapy. Results of a prospective naturalistic research study]. / Adaptive Indikationsstellung in der ambulanten psychodynamischen Kurzzeitpsychotherapie. Ergebnisse einer prospektiven naturalistischen Verlaufsuntersuchung.

Health care insurers in Germany fund long-term psychotherapy of up to 240 sessions as well as brief psychotherapeutic interventions of up to 25 sessions. In a former study, it was observed that a substantial proportion of interventions initially designed as brief psychotherapy were changed into long-term therapy. The present study investigated the criteria of such decisions to change treatment plans and is part of a more comprehensive auditing study in outpatient psychotherapy. Twenty-six psychotherapists in private practice participated in the study. During a 12-month recruitment period, 70 patients started with brief psychodynamic psychotherapy. Thirty-six therapies were evaluated according to the study protocol. The results provide evidence that motivation for psychotherapy, satisfaction with the results of therapy, persistence of psychological symptoms at the end of short-term intervention, and aspects of the patient's personality are factors predictive of treatment selection. Patients who changed from short-term to long-term therapy were more motivated towards their therapy (prognostic indication), displayed more severe symptoms, were less satisfied with the results of short-term psychotherapy (adaptive indication), and scored higher on the "structure of personality organization" parameter according to the OPD diagnostic system.