Cooling and Autonomous Feedback in a Bose-Hubbard Chain with Attractive Interactions.

We engineer a quantum bath that enables entropy and energy exchange with a one-dimensional Bose-Hubbard lattice with attractive on-site interactions. We implement this in an array of three superconducting transmon qubits coupled to a single cavity mode; the transmons represent lattice sites and their excitation quanta embody bosonic particles. Our cooling protocol preserves the particle number-realizing a canonical ensemble-and also affords the efficient preparation of dark states which, due to symmetry, cannot be prepared via coherent drives on the cavity. Furthermore, by applying continuous microwave radiation, we also realize autonomous feedback to indefinitely stabilize particular eigenstates of the array.

Microscopic theory of non-adiabatic response in real and imaginary time.

We present a general approach to describe slowly driven quantum systems both in real and imaginary time. We highlight many similarities, qualitative and quantitative, between real and imaginary time evolution. We discuss how the metric tensor and the Berry curvature can be extracted from both real and imaginary time simulations as a response of physical observables. For quenches ending at or near the quantum critical point, we show the utility of the scaling theory for detecting the location of the quantum critical point by comparing sweeps at different velocities. We briefly discuss the universal relaxation to equilibrium of systems after a quench. We finally review recent developments of quantum Monte Carlo methods for studying imaginary time evolution. We illustrate our findings with explicit calculations using the transverse-field Ising model in one dimension.

Adiabatic nonlinear probes of one-dimensional bose gases.

We discuss two complimentary problems: adiabatic loading of one-dimensional bosons into an optical lattice and merging two one-dimensional Bose systems. Both problems can be mapped to the sine-Gordon model. This mapping allows us to find power-law scalings for the number of excitations with the ramping rate in the regime where the conventional linear response approach fails. We show that the exponent of this power law is sensitive to the interaction strength. In particular, the response is larger, or less adiabatic, for strongly (weakly) interacting bosons for the loading (merging) problem. Our results illustrate that in general the nonlinear response to slow relevant perturbations can be a powerful tool for characterizing properties of interacting systems.

Neuroradiological investigations in secondary headaches.

In this work, we examine the neuroradiologic features of the main non vascular clinical conditions responsible for secondary headache; excluding CSF hypotension, which will be treated extensively in another work in this supplement. Headache is not a constant feature of intracranial mass lesions, even of large extension. Headache has a high diagnostic value in children, as it can be the only heralding symptom, sometimes even for a long time, of severe intracranial pathologies, which later give rise to seizure or focal neurological signs. Particular attention should be paid to children affected by leukaemia under pharmacological treatment, in which headache is almost always the presenting symptom of serious neurological syndromes, consequent to antiblastic drugs.

Hemorrhage after an acute ischemic stroke.MAST-I Collaborative Group.

BACKGROUND AND PURPOSE: Hemorrhagic transformation is frequently seen on CT scans obtained in the subacute phase of ischemic stroke. Its prognostic value is controversial. METHODS: We analyzed 554 patients with acute ischemic stroke enrolled in the Multicenter Acute Stroke Trial-Italy (MAST-I) study in whom a second CT scan was performed on day 5. Presence of 1) intraparenchymal hemorrhages (hematoma or hemorrhagic infarction), 2) extraparenchymal bleeding (intraventricular or subarachnoid) and 3) cerebral edema (shift of midline structure, sulcal effacement or ventricular compression) alone or in association were evaluated. Death or disability at 6 months were considered as "unfavorable outcome." RESULTS: Patients who developed intraparenchymal hemorrhages, extraparenchymal bleeding, or cerebral edema had unfavorable outcome (83%, 100%, and 80%, respectively), but multivariate analysis demonstrated that only extraparenchymal bleeding (collinearity) and cerebral edema (OR=6.8; 95% CI, 4.5 to 10.4) were significant independent prognostic findings. Unfavorable outcome correlated with size of intraparenchymal hemorrhage (chi2 for trend=30.5, P<0.0001). Nevertheless, when a large hematoma was present the negative effect was mostly due to concomitant extraparenchymal bleeding (chi2=51.6, P<0.0001), and when hemorrhagic infarction was detected the negative effect was mostly explained by the association with cerebral edema (chi2=36.6, P<0.0001). CONCLUSIONS: Extraparenchymal bleeding and cerebral edema are the main prognostic CT scan findings in the subacute phase of ischemic stroke. Stroke patients with a high risk for developing these 2 types of brain damage should be identified. Measures to prevent and adequately treat their development should be implemented.

Dissecting vertebral aneurysm. Report of a case.

Aneurysms of the vertebral artery (VA) are relatively uncommon, accounting for less than 0.5-3.0% of all aneurysms and 20% of aneurysms originating in the posterior fossa. There are three distinct forms of aneurysms: saccular, fusiform and dissecting. The diagnosis of dissecting aneurysm is based on the findings of angiography, surgery and autopsy. Irregular fusiform appearance, intramural retention of contrast medium in the venous phase and alternating irregular stenotic and dilated segment (string and pearl sign) are the basal angiographic findings. Patients with dissection of VA often develop subarachnoid hemorrhages (SAHs), with the typical neck pain or suffer cerebral ischemia. Because of the high risk of rebleeding of dissecting aneurysms, they should be treated as soon as possible, with occlusion of the VA. Nowadays, both surgical and endovascular procedures allow the treatment of dissecting vertebral aneurysms. Anyway, one should be aware that vertebral occlusion performed proximal to PICA origin may be followed by ischemic complications. In this paper, we discuss the diagnostic and therapeutic difficulties associated with dissecting vertebral aneurysms on the basis of personal observation and a review of the literature.

Reliability of hemorrhagic transformation diagnosis in acute ischemic stroke.

BACKGROUND AND PURPOSE: Diagnosis of hemorrhagic transformation (HT) could influence the prognosis and the management of acute ischemic stroke. The interobserver reliability of CT-scan HT classification is evaluated in the present study. METHODS: Fifty 5-day CT scans of patients enrolled in the Multicenter Acute Stroke Trial-Italy (MAST-I) were reviewed independently by two neuroradiologists and one neurologist with CT training. They evaluated the presence and type of intraparenchymal HT (hemorrhagic infarction types I, II, and III and intracerebral hemorrhage) (five-item scale), as well as the presence of intraventricular and/or subarachnoid bleeding according to standardized definitions. RESULTS: Agreement for exclusion of HT and intraventricular/ subarachnoid bleeding was good between the neuroradiologists (kappa = 0.70 and kappa = 0.72) and excellent between the neurologist and each neuroradiologist (kappa = 0.87 and kappa = 0.77, kappa = 0.83, and kappa = 0.81, respectively). The overall agreement for the five-item HT scale between the two neuroradiologists was good (kappa n = 0.65) because of discordance over the last three items. Better overall agreement was obtained with a three-item scale: no hemorrhage, petechial type I hemorrhagic infarction, and other HT (type II and type III hemorrhagic infarction and intracerebral hemorrhage) together (kappa w = 0.82 CONCLUSIONS: Exclusion of HT is a reliable CT diagnosis when made by neuroradiologists and also by a neurologist with CT training. Five- and three-item scales of HT types showed good to excellent reliability. The validity of the scale for predicting short- and long-term outcome should be evaluated in future studies.

Correlation between cranial computed tomographic scans at diagnosis in children with acute lymphoblastic leukaemia and central nervous system relapse.

145 children with acute lymphoblastic leukaemia (ALL) were evaluated over a period of 3 years in a multicentre study in which serial cranial computed tomographic (CT) scans of the brain were done. All patients were symptom-free. CT scans were graded as normal, borderline (slight or moderate cerebral atrophy), or pathological (severe cerebral atrophy). 62% (90/145) of children had CT scan abnormalities at diagnosis. After a median follow-up of 24 months (range 6-36) 12 of 108 evaluable patients had central nervous system (CNS) relapses (6 isolated relapses and 6 combined with relapse at another site). All patients with CNS relapse had an abnormal CT scan at diagnosis (8 pathological and 4 borderline). No relapses were observed among the 42 patients with a normal cranial CT scan at diagnosis. A significantly higher proportion of severe cerebral atrophy, both following CNS prophylaxis and after the discontinuation of treatment, was found among patients with a borderline CT scan at diagnosis than among patients with a normal CT scan at diagnosis. Thus an abnormal cranial CT scan at diagnosis in children with ALL seems to have prognostic significance.

Size reduction of an ACTH-secreting pituitary macroadenoma in Nelson's syndrome by sodium valproate: effect of withdrawal and re-institution of treatment.

We describe herein the reduction in the size of an ACTH-secreting pituitary macroadenoma in a patient with Nelson's syndrome during chronic administration of sodium valproate, and the changes in tumour volume after withdrawal and re-institution of treatment. The patient had elevated plasma ACTH levels (1123-1255 pmol/l), which increased markedly after CRH stimulation. A first 4-month course of sodium valproate administration (600 mg/day, orally) was started. Plasma ACTH fell to 550-726 pmol/l with persistence of responsiveness to CRH; brain computed tomography showed a clearcut reduction of tumour size. One month after drug withdrawal, the tumour volume appeared unchanged and plasma ACTH values ranged between 374 and 440 pmol/l. One and a half year after drug withdrawal, a brain computed tomography showed re-expansion of the pituitary adenoma with evidence of suprasellar extension, which had never been seen previously. Plasma ACTH ranged between 113 and 199 pmol/l. A second course of sodium valproate was started; after three months, a brain computed tomography documented clearcut reduction of tumour volume from a suprasellar extension to a partially empty pituitary fossa. Plasma ACTH ranged from 396 to 542 pmol/l with persistence of responsiveness to CRH. The present report documents for the first time the reduction of tumour size in a patient with an ACTH-secreting macroadenoma by chronic administration of sodium valproate.

Embolization of vascular malformations of the spinal cord.

Twelve patients with vascular malformations of the spinal cord have been treated by embolization at the Neuroradiological Department of the Ospedale Maggiore Niguarda Cà Granda from September 1981 to February 1984. Different materials and techniques have been used, including liophylised dura, Ivalon (PVA) and Isobutyl Cianoacrylate. All types of malformations have been encountered: dural AV fistulae, intramedullary AVMs, intradural extramedullary AV fistulae, extradural AVMs with intradural venous drainage. Nine patients improved following treatment and three remained unchanged. Embolization can be an alternative treatment to surgery and it is the treatment of choice in dural AV fistulae.

[The Sturge-Weber syndrome. Tomodensitometric diagnosis]. / La sindrome di Sturge-Weber. Diagnosi tomodensitometrica.

Radiological diagnosis of Sturge-Weber's disease is based on the recognition of the characteristic "tram-line" type of calcification at routine skull X ray examination. Computerized tomography allows an earlier diagnosis since it shows smaller calcifications. It also provides a better appreciation of the associated parenchimal anomalies, such as cerebral atrophy, and an exact evaluation of the extent of the pial angiomatosis following intravenous injection of contrast. In four children with Sturge-Weber's disease CT clearly revealed the full extent of calcifications and vascular anomaly; in one of the children the diagnosis was possible before the appearance of the calcifications.

Prophylactic treatment of the central nervous system in acute lymphoblastic leukemia. CT findings in 45 children off therapy.

45 children with ALL treated with intrathecal Methotrexate and radiation therapy, all in hematologic remission, have been examined with brain CT at intervals varying from 3 to 6 years after completion of CNS prophylaxis. Abnormalities were detected in 20% of the children; the main findings were: calcifications within the brain parenchyma in 3 patients; enlargement of the ventricular system and/or sulci in 8. The 3 patients with calcifications had seizures during or after treatment whereas those with dilatation of the ventricular system or sulci presented no neurological signs.

CT evaluation in patients with transient ischemic attack. Correlation between clinical and angiographic findings.

35 patients clinically diagnosed with transient ischemic attack (TIA) and 15 patients clinically diagnosed with reversible ischemic neurological deficits (RIND) were examined by computerized tomography (CT). 34% of TIA patients showed positive CT scans consisting of small hypodenase areas: 60% of RIND patients had larger lesions. In 20% of the overall group the only pathological finding consisted of unilateral focal atophy or ventricular asymmetry. Correlation between angiographically demonstrated atherosclerotic lesions and positive CT was high. On the contrary, no correlation was found between either the risk factors or the natural history of ischemic attack and positive CT findings.

[Computerized axial tomography. Technical principles, clinical application, organizational aspects]. / La tomografia assiale computerizzata. Principi tecnici, applicazione clinica, aspetti organizzativi.

The technical principles, clinical application and organisational problems associated with computerised axial tomography are discussed. Numerous examples of pictures obtained on the brain and the whole body and in the normal subjects and various diseases are presented.

Ectasia of the intracranial arteries diagnosed by computed tomography. Megadolichobasilar artery: CT diagnosis.

The megadolichobasilar anomaly may be diagnosed by CT as an extra-axial lesion in the cerebellopontine angle. It enhances in a tubular fashion after intravenous injection of contrast. Hydrocephalus resulting from obstruction of CSF circulation may be demonstrated.

Intimal and medial calcifications of the carotid siphon and cerebrovascular disease.

Skull films of 5,570 patients older than 40 years of age admitted to the neurological (4,308), ophthalmologic (1,151), and otorhinolaryngologic clinics (111) of the University of Milan over a period of 20 years were reviewed for carotid siphon calcification. The 485 positive findings were divided into intimal and medial calcifications on the basis of morphological criteria. Signs of cerebrovascular disease in the territory of the internal carotid artery were seen in 35.1% of the intimal group and 37.2% of the medial group. These findings suggest that the two types of calcification do not have different prognostic values as theorized previously.