Thermal and Residual Excited-State Population in a 3D Transmon Qubit.

Remarkable advancements in coherence and control fidelity have been achieved in recent years with cryogenic solid-state qubits. Nonetheless, thermalizing such devices to their milliKelvin environments has remained a long-standing fundamental and technical challenge. In this context, we present a systematic study of the first-excited-state population in a 3D transmon superconducting qubit mounted in a dilution refrigerator with a variable temperature. Using a modified version of the protocol developed by Geerlings et al., we observe the excited-state population to be consistent with a Maxwell-Boltzmann distribution, i.e., a qubit in thermal equilibrium with the refrigerator, over the temperature range 35-150 mK. Below 35 mK, the excited-state population saturates at approximately 0.1%. We verified this result using a flux qubit with ten times stronger coupling to its readout resonator. We conclude that these qubits have effective temperature T(eff)=35 mK. Assuming T(eff) is due solely to hot quasiparticles, the inferred qubit lifetime is 108 µs and in plausible agreement with the measured 80 µs.

Current-induced switching of perpendicularly magnetized magnetic layers using spin torque from the spin Hall effect.

We show that in a perpendicularly magnetized Pt/Co bilayer the spin-Hall effect (SHE) in Pt can produce a spin torque strong enough to efficiently rotate and switch the Co magnetization. We calculate the phase diagram of switching driven by this torque, finding quantitative agreement with experiments. When optimized, the SHE torque can enable memory and logic devices with similar critical currents and improved reliability compared to conventional spin-torque switching. We suggest that the SHE torque also affects current-driven magnetic domain wall motion in Pt/ferromagnet bilayers.

Fractures of the fifth metacarpal.

BACKGROUND: The literature is limited concerning the epidemiological issues of fracture in the fifth metacarpal bone. PURPOSE: To explore the incidence and types of this fracture, and how the fracture is related to age, gender, trauma mechanism, and at what day of the week the causing trauma occurred. MATERIAL AND METHODS: All hand fractures registered at the Department of Radiology, Buskerud Hospital, Norway, in the period between 2004 and 2006 were reviewed. RESULTS: Of 1475 hand fractures, 271 (18.4%) were located in the fifth metacarpal bone. In 130 of these cases (121 male, nine female), the trauma had occurred through aggression, such as a fistfight or from punching a hard object. The majority of fractures were located in the neck of the metacarpal bone (boxer's fracture). The median age of this group was 22 (7-51) years. Concerning the time of trauma, there was a significant peak during weekends (95 patients). One hundred forty-one of the fifth metacarpal fractures were caused by accidental trauma (99 males, 42 females). In this group, the fractures were located approximately equally in the subcapital, diaphyseal, and basal part of the metacarpal. The median age was 34 (2-90) years. The accidental traumas occurred about as often during the weekdays as during the weekend. CONCLUSION: Of all hand fractures, fractures of the fifth metacarpal bone are the most common. There are as many aggression-related fractures as accidental fractures in the fifth metacarpal bone. When the fracture is caused by aggression, the typical patient is a young male sustaining fracture during the weekend.

Frequency and timing of clinical venous thromboembolism after major joint surgery.

Over a 13-year period we studied all patients who underwent major hip and knee surgery and were diagnosed with objectively confirmed symptomatic venous thromboembolism, either deep venous thrombosis or non-fatal pulmonary embolism, within six months after surgery. Low-molecular-weight heparin had been given while the patients were in hospital. There were 5607 patients. The cumulative incidence of symptomatic venous thromboembolism was 2.7% (150 of 5607), of which 1.1% had developed pulmonary embolism, 1.5% had deep venous thrombosis and 0.6% had both. Patients presented with deep venous thrombosis at a median of 24 days and pulmonary embolism at 17 days after surgery for hip fracture. After total hip replacement, deep venous thrombosis and pulmonary embolism occurred at a median of 21 and 34 days respectively. After total knee replacement, the median time to the presentation of deep venous thrombosis and pulmonary embolism was 20 and 12 days respectively. The cumulative risk of venous thromboembolism lasted for up to three months after hip surgery and for one month after total knee replacement. Venous thromboembolism was diagnosed after discharge from hospital in 70% of patients who developed this complication. Despite hospital-based thromboprophylaxis, most cases of clinical venous thromboembolism occur after discharge and at different times according to the operation performed.

Acute osteomyelitis as a complication of varicella.

Varicella is a common viral infection in childhood, and acute osteomyelitis is one of the rare but serious complications. We report two cases of osteomyelitis as a complication of varicella. The possibilities and limitations of the different imaging modalities are discussed, as well as imaging findings during the course of this condition.

Late occurring clinical deep vein thrombosis in joint-operated patients.

In a prospective study of 4,840 patients, we determined the annual incidence of clinical deep vein thrombosis (DVT) in mobilized, discharged orthopedic-operated "high-risk" patients (hip replacement surgery, knee replacement surgery, nailed hip fracture) and assumed "low-risk" patients (diagnostic knee arthroscopy). In addition, the time from the operation to the time when the patients were readmitted with clinically suspected DVT and the distribution of radiologically-confirmed DVT were recorded. Thromboprophylaxis was routinely given for about 10 days to the high-risk groups during the hospital stay but not to patients undergoing knee arthroscopy. During 9 years, the annual incidence of DVT following major procedures was 2.1% (95% CI 1.6-2.6) vs. 0.6% (95% CI 0.2-1.1) after diagnostic knee arthroscopy. Symptoms appeared, on average, 27 (3-150) days after total hip replacement surgery, 36 (3-150) days after nailed hip fracture, 17 (6-30) days after total knee replacement and 1 (1-6) day after knee arthroscopy. In hip-operated patients, 50% of the DVTs were found in the proximal veins vs. 40% following knee arthroplasty.

Three dimensional CT evaluation of occipito-atlanto-axial dislocation in rheumatoid arthritis.

Involvement of the upper cervical spine, with possible instability and dislocation of the atlanto-axial-cervico-occipital joints in patients with rheumatoid arthritis (RA), is routinely monitored with conventional radiographs. As disease progresses severe interpretation problems occur, especially when looking for cranial migration of the odontoid process. The aim of the present study was to evaluate whether three dimensional CT examination should be considered for such monitoring. After clinical and biochemical examination of 20 consecutive patients, diagnostic information about cranial migration of the odontoid process was obtained by conventional radiograms and by three dimensional CT examination. When using conventional radiographs the odontoid process and the its relation to the skull base could be outlined in 8 of the 20 patients. whereas all bony structures could be well demonstrated on the CT examination and the degree of cranial migration into the foramen magnum could be quantified. Three dimensional CT should be considered as a reliable examination for monitoring RA patients with involvement of the upper cervical spine and a possible cranial migration of the odontoid process.

[Osteomyelitis as a complication of varicella]. / Osteomyelitt som komplikasjon ved varicella.

Osteomyelitis is a rare complication after varicella. It should, however, be considered in any child who develops pain in a limb during or after a varicella infection. An 18 month old boy with a five day history of varicella infection was hospitalized. Movement of his right arm made him cry intensively. Blood cultures showed growth of group A beta haemolytic streptococcus. The day after admission to hospital the bone scintigrams showed increased activity in the right humeral diaphysis consistent with osteomyelitis, and penicillin therapy was started. On radiograms of the right humerus performed on the second day, no pathological changes could be shown. Radiograms after ten days showed irregular osteolytic lesions in the upper part of the humeral diaphysis. Clinically, the boy improved rapidly and could be dismissed from hospital after 17 days. Follow-up radiograms showed slowly normalized conditions, and five months after the start of symptoms, no pathological changes should be demonstrated.

[Krukenberg tumor. A seldom considered condition?]. / Krukenbergs tumor. En lite påaktet tilstand?

In 1896, Krukenberg described what he presumed was a new type of primary ovarian neoplasm. The true metastatic nature of this lesion was established six years later. Some 10% of all ovarian malignant lesions are regarded as metastatic. Of these, approximately 50% are Krukenberg tumours. The tumour is well defined histologically and is usually secondary to a tumour in the gastrointestinal tract. We describe the case of a 48 year old woman with gastric cancer who, three years after diagnosis and subsequent total gastrectomy, was referred to us for observation with peritoneal involvement. We stress the importance of careful clinical and radiological follow-up of female patients with gastrointestinal cancer.

[Abnormality as differential diagnosis in atlas fracture]. / Anomali som differensialdiagnose ved atlasfraktur.

In some patients, suspected fractures of the cranial part of the cervical spine are difficult to diagnose properly without the use of computed tomography or MT. In addition to imaging and positioning problems, the possibility of anomalies of the atlas vertebra may complicate the diagnostic considerations. Proper knowledge of such anomalies may facilitate the diagnostic procedures. The diagnostic problems are discussed, and are illustrated through two patients recently examined in our department.

Autosomal dominant osteopetrosis: report of a Norwegian family with radiographic or anamnestic findings differing from the generally accepted classification.

OBJECTIVE: Autosomal dominant osteopetrosis is currently divided into two, possibly three subgroups. The present study of a Norwegian family, however, suggests that such a grouping is not generally valid. PATIENTS AND METHODS: A Norwegian family has been studied over four generations. Information about the two older generations was obtained mainly from hospital files and by interviewing members of the family. Radiographs were obtained from the two younger generations. RESULTS AND CONCLUSION: Of a total 14 family members, nine patients consisting of six women and three men were studied. Within the same family, patients could be classified as belonging to different subgroups of osteopetrosis defined elsewhere, and at least three of them could be classified as belonging to more than one group. The present study suggests that the generally accepted classification of autosomal dominant osteopetrosis should be questioned.

Imaging routines for the esophagus, small bowel, abdomen, and liver in six Norwegian hospitals from 1975 to 1993.

The roles of liver scintigraphy in addition to other imaging modalities of the esophagus and the small bowel and the use of abdominal flat films were studied in six Norwegian hospitals between 1975 and 1993. Parallel to the introduction of ultrasonography, the use of liver scintigraphy disappeared almost completely. Barium studies of the esophagus, to some degree, have been replaced by endoscopy, whereas use of barium studies of the small bowel remained unchanged or increased. The number of flat-film studies of the abdomen performed remained unchanged.

[Arteriovenous fistula as a complication of percutaneous renal biopsy]. / Arteriovenøs fistel som komplikasjon etter perkutan nyrebiopsi.

Arteriovenous fistulae is a well known but rarely diagnosed complication of percutaneous biopsy of kidney allografts. In most cases the fistula are clinically occult. Most of the remaining fistulas disappear spontaneously. However they may result in severe bleeding, uncontrollable hypertension or deterioration of renal function. These are features that may require correction, either surgically or by arteriographic embolition. Between 1991 and 1994 arteriovenous fistulas were identified in two patients who had undergone percutaneous renal biopsy. In our cases the fistulas never became clinically significant.

Changes in radiological routines following the introduction of computed tomography. A retrospective study from two Norwegian hospitals.

Diagnostic imaging routines have changed rapidly during the last two decades. The real revolution started with the introduction of computed tomography into routine clinical work in the middle of the 1970s. Simultaneously, a tremendous sophistication of ultrasonography took place, and shortly later, magnetic resonance imaging started its "career." The present report explores how the introduction of computed tomography changed imaging routines in two major Norwegian hospitals during the last 10 to 15 years.

Changes in diagnostic imaging routines of the stomach and the large bowel during the period between 1975 and 1992.

In a retrospective study on diagnostic imaging of the stomach and large bowel, we evaluated the examination routines in six Norwegian hospitals for the period between 1975 and 1992. For both organ systems, a shift in routines from radiological examination toward endoscopy was observed. For the stomach there was a significant correlation between an increase in the use of endoscopy and a decrease in the use of X-ray examinations. Additionally, the total number of stomach examinations had declined. For the large bowel, the total number of endoscopic and radiological examinations had increased for all hospitals studied. While not as prominent as for the stomach, an obvious shift from X-ray examinations toward endoscopy was observed. These results should be considered when planning new imaging departments and hospitals in Norway.

Ultrasonography in medical imaging. Influence on diagnostic routines.

It has been assumed that the introduction of ultrasonography in diagnostic imaging has led to dramatic changes in imaging routines by replacing other modalities like angiography, intravenous urography, and computerized tomography in several diagnostic procedures. The present retrospective study from five Norwegian hospitals during the period from 1978 to 1991 confirm this assumption, showing how ultrasonographic examinations have influenced diagnostic routines.

[Diagnostic imaging of the gastrointestinal and biliary tracts. Pattern of examinations during the period 1975-90]. / Bildediagnostikk av gastrointestinalkanalen og galleveiene. Undersøkelsesmønsteret 1975-90.

The procedures used for imaging of the gastrointestinal tract, the gall bladder and the bile ducts were registered in six Norwegian hospitals during the period 1975-90. Data obtained from all hospitals showed a significant decrease in radiological examinations of the stomach and the large bowel, and a dramatic decrease of such examinations in the case of the gall bladder and bile ducts. The changes are mainly due to the increasing use of newer methods such as ultrasonography, gastroscopy and colonoscopy. The shift in the pattern of examinations, as shown in the present study, may well have many implications for patients and for the health service as a whole.

[Synovial chondromatosis]. / Synovial kondromatose.

Synovial chondromatosis is a rare monarticular condition in which cartilaginous masses are formed by metaplasia of the synovial membrane. These masses may calcify and ossify. The disease most commonly affects the knee, and the symptoms include pain, swelling, locking and palpable loose bodies. Although the clinical features are usually non-specific, the roentgenograms often provide important diagnostic information. Synovial chondromatosis is rarely a difficult diagnostic problem, but should not be confused with other disorders that give rise to loose bodies, such as degenerative joint disease and osteochondritis dissecans. Two cases are described and synovial chondromatosis is discussed in some detail, including radiological features and treatment.

Radiological examinations of the urinary tract. Changes during the last 24 years.

Procedures for imaging the urinary tract have been recorded in six Norwegian hospitals for the last 24 years. For three of the hospitals, data were collected from 1965 to 1989, and for the other three from 1966, 1971 and 1975, respectively. There was a significant reduction in the number of intravenous pyelograms, voiding cystograms, and renal angiograms, but the number of retrograde pyelograms and plain radiographs of the urinary tract remained constant. Computed tomography of the urinary tract increased during the first years, but after the introduction of ultrasonography, the number of computed tomograms decreased. Ultrasonographic examinations of the urinary tract are still rapidly increasing, and seem to have replaced some of the other imaging techniques. The present results should be taken into consideration when planning the health care for the future.