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.

[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.

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.

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.

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.

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).

[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.

Psychosomatic aspects in patients with central serous chorioretinopathy.

AIMS: Patients with central serous chorioretinopathy were tested for psychosomatic symptoms and social support at the onset of their ailments; their personality profiles were also tested. METHODS: 24 consecutive outpatients at the department of ophthalmology, Freiburg University Hospital, Freiburg, Germany, presenting with central serous chorioretinopathy filled in the following standardised questionnaires: Symptom Checklist 90-R (SCL 90-R), Symptom List, Questionnaire on Social Support, and Sixteen Personality Factor Questionnaire. RESULTS: The sample (n=24) included 22 male patients with an average age of 44.1 years. Three quarters of the patients have children and live with their families; three quarters are white collar workers or self employed; one quarter are skilled blue collar workers. 12 patients were suffering from the ailment for the first time; 12 patients were undergoing a relapse. Mean visus of the affected eye was 0.8. The Symptom List yielded an inconspicuous total score for psychosomatic symptoms. In the SCL 90-R, nine out of 24 patients (37%) evinced elevated psychic stress. The total value of the questionnaire on social support showed good social support. In the Sixteen Personality Factor Questionnaire, the patients showed heightened emotional instability and insecurity as well as flexibility and spontaneity. CONCLUSION: The sociodemographic data confirm that central serous chorioretinopathy is predominantly an ailment of middle aged, socially well integrated men. This study suggests elevated psychic stress a few weeks after the onset of the ailment. The personality factors in the patients with central serous chorioretinopathy found in this study have to be verified with other populations. These results did not clearly show that psychosocial factors have a definite role in the aetiology of central serous chorioretinopathy. In order to make any clear assertions about this matter, further longitudinal studies on the progression of psychosocial parameters with larger patient samples would be indispensable.

Annexins I to VI: quantitative determination in different human cell types and in plasma after myocardial infarction.

Concentrations of annexins I to VI were quantitatively determined in extracts of placenta and different human cell types. They were detectable in all extracts studied, but lymphocytes/monocytes, endothelial cells and fibroblasts had very high annexin contents. The results indicate cell type specific annexin-repertoires. Annexins are intracellular proteins lacking signal sequences but which are detectable in trace amounts in plasma of healthy humans. The majority of plasma samples drawn from 14 patients suffering from myocardial infarction had elevated annexin III, IV and V concentrations. Shortly after infarction increased annexin levels were detected, reaching maximal values 24 to 48 h later. In the course of the following days annexin concentrations returned towards normal plasma levels.

Tubular proteinuria in IgA glomerulonephritis.

In the renal biopsy samples of some patients with IgA glomerulonephritis (IgA GN), tubulointerstitial changes and a significant correlation between these changes and the serum creatinine levels had been observed earlier. In order to get an insight into the function of the tubules, 45 patients with IgA GN have been examined for proteinuria with special reference to low molecular weight (LMW) proteins, also called tubular proteins using sodium-dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE). Thirty-seven of the 45 patients had proteinuria (200-1890 mg/day). On the basis of the middle molecular weight/high molecular weight (MMW/HMW) protein ratio, the proteinuria was non-selective in 28. Twenty-nine patients had 40-200 mg LMW protein/day in the urine. There was a statistically significant correlation between the tubulointerstitial changes seen in the renal biopsy samples (characterized by the tubulointerstitial index) and the tubular proteinuria. On the basis of these results it is suggested that in most patients with IgA GN there is, in addition to the glomerular lesion, also morphological and functional tubulointerstitial damage, which is in connection with the progression of the disease.

Herpes virus antigens and antibodies in kidney biopsies and sera of IgA glomerulonephritic patients.

Antibody titers against 4 viruses of the herpes group have been studied in the sera of 54 patients with IgA glomerulonephritis (GN). The incidence of antibodies to herpes simplex virus type-1 (HSV-1), HSV-2, cytomegalovirus (CMV), Epstein-Barr virus nuclear antigen (EBNA), and that of IgG antibodies to EBV virus capsid antigen (VCA) were similar in patients and in controls. However, elevated antibody titers (greater than or equal to 64) to HSV and CMV occurred more frequently in patients with IgA GN than in healthy controls. Geometric mean titers to HSV and CMV were also higher in patients suffering from IgA GN than in controls. The incidence of IgA antibodies to EBV VCA occurred in patients with IgA GN significantly more often than in controls. There was a trace amount of HSV-2 antigen in 2 glomeruli of 1 renal biopsy. It is concluded that, in some patients with IgA GN, there is an abnormal immune response to certain types of herpes viruses.

[Chylous ascites, a rare complication of aortic surgery]. / Chylaszites, eine seltene Komplikation in der Aortenchirurgie.

Less than 1% of all complications following vascular surgery of the abdominal aorta involve the lymphatic system. We report on a case of Chylous ascites following the operation of a ruptured infrarenal aortic aneurysm. The primary therapy, administered over a period of five weeks, consistent of diuretics and substitution by human albumin. However, the chylous flow did not decrease. A surgical intervention by a retroperitoneal ligation to try to stop the lymph flow also failed. Finally a total parental nutrition was followed by decrease and arrest of the lymph flow. Conservative treatment of this complication is considered as therapy of choice.

Ruptured infrarenal aortic aneurysm--a critical evaluation.

BACKGROUND: Objective evaluation of the management of patients with ruptured infrarenal aortic aneurysm in emergency situations has been described rarely. PATIENTS AND METHODS: Fifty-two consecutive patients with ruptured infrarenal aortic aneurysm (mean age, 70.3 years; range, 56-89 years; SD 7.8) were admitted between January 1993 and March 1998. Emergency protocols, final reports, and follow-up data were analyzed retrospectively. APACHE II scores at admission and fifth postoperative day were assessed. RESULTS: The time between the appearance of first symptoms and the referral of patients to the hospital was more than 5 hours in 37 patients (71%). Thirty-eight patients (71%) had signs of shock at time of admission. Ultrasound was performed in 81% of patients as the first diagnostic procedure. The most frequent site of aortic rupture was the left retroperitoneum (87%). Intraoperatively, acute left ventricular failure occurred in four patients, and cardiac arrest in two others. The postoperative course was complicated significantly in 34 patients. The overall mortality rate was 36.5% (n = 19). In 35 patients, APACHE II score was assessed, showing a probability of death of more than 40% in five patients and lower than 30% in 17 others. No patient showing probability of death of above 75% at the fifth postoperative day survived (n = 7). CONCLUSIONS: Ruptured aortic aneurysm demands surgical intervention. Clinical outcome is also influenced by preclinical and anesthetic management. The severity of disease as well as the patient's prognosis can be approximated using APACHE II score. Treatment results of heterogeneous patient groups can be compared.

Diagnosis and management of trauma and iatrogenic induced arteriovenous fistulas in the neck.

Trauma-induced arteriovenous (av) communications in the cervical region involving the external carotid artery and the jugular vein are exceptionally rare. Moreover, an iatrogenic av fistula between the vertebral artery and the vein after insertion of a venous catheter into the internal jugular vein is described. The discussion includes the clinical presentation, diagnosis and management of such rare av fistulas.

[Single intervention for treatment of Salmonella typhimurium-induced symptomatic abdominal aortic aneurysm with spondylitis]. / Die einzeitige Behandlung eines durch Salmonella typhimurium induzierten symptomatischen Bauchaortenaneurymas mit Spondylitis.

Simultaneous treatment of Salmonella typhimurium-induced symptomatic abdominal aortic aneurysm with associated spondylitis. Bacterially infected aneurysms associated with local spondylitis, while representing a potentially fatal clinical picture, are an operative challenge for vascular surgeons and orthopaedic surgeons alike. In this context, the concurrent occurrence of an infection with Salmonella typhimurium as a causative agent is a rare observation. The case report gives an outline of the simultaneous vascular and orthopaedic surgical procedure. The subrenal mycotic aneurysm was removed in a first step. The continuity of the aorta was restored centrally through an autogenic aortic graft with caudal anastomosis to a dacron vascular prosthetic tube. Initially, the latter was chosen of excessive length so as to facilitate the orthopaedic surgeon's approach. Upon completion of stabilising surgery of the vertebral column, the dacron tube was reduced in length as necessary and the surgical area was enclosed with an omentum majus plastic mesh. No complications were noted during the 18-month follow-up period.

Ultrastructural analysis of an infected collagen-coated vascular graft.

The incidence of infection following arterial reconstruction using synthetic graft materials varies from less than 1 to 5%. One of three mechanisms is thought to be responsible: 1. intraoperative contamination, 2. extension from adjacent infected or colonized tissue, or 3. hematogenous or lymphogenous seeding. We present ultrastructural data of a patient with a polymicrobial graft infection due to a prostheto-enteric fistula 16 years after reconstruction of an aortobifemoral graft. The polymer surface showed signs of biodegradation and was completely covered with a layer of plasma proteins. Disrupted fibroblasts on the intersegmental graft surface were surrounded by bundles of collagen. Gram-negative rods and grampositive cocci were embedded in an extracellular EPS matrix. Bacterial culture confirmed growth of Eikenella corrodens, Fusobacterium nucleatum and Peptostreptococcus species. Fibrin and granulation tissue from the neoadventitia started to mark off the inflammatory process. Transmission electron microscopy is a valuable tool for the investigation of alloplastic arterial devices. After 16 years of implantation the graft shows different signs of biodegradation.

Percutaneous treatment of rare latrogenic arteriovenous fistulas of the lower limbs.

Postoperative iliac and popliteal arteriovenous fistulas are extremely rare. This article describes the percutaneous endovascular treatment of iatrogenically induced arteriovenous fistula in two patients with simultaneous use of intravascular ultrasound. In a 61-year-old woman, a fistula between popliteal artery and vein, inadvertently created during implantation of a prosthetic knee joint, was treated with a novel polytetrafluorethylene (PTFE) stent graft. A 48-year-old man underwent endovascular treatment of a large fistula between the right common iliac artery and the left common iliac vein, inadvertently induced during surgery on an intervertebral disc. Congestive heart failure induced by the arteriovenous communication was reduced rapidly. Our results indicate that percutaneous treatment in conjunction with intravascular ultrasound is a useful therapeutic option for vascular lesions. It is less invasive than open vascular reconstruction and has a comparably high success rate.