224 research outputs found
Fast, Efficient Calculations of the Two-Body Matrix Elements of the Transition Operators for Neutrinoless Double Beta Decay
To extract information about the neutrino properties from the study of
neutrinoless double-beta (0\nu\beta\beta) decay one needs a precise computation
of the nuclear matrix elements (NMEs) associated with this process. Approaches
based on the Shell Model (ShM) are among the nuclear structure methods used for
their computation. ShM better incorporates the nucleon correlations, but have
to face the problem of the large model spaces and computational resources. The
goal is to develop a new, fast algorithm and the associated computing code for
efficient calculation of the two-body matrix elements (TBMEs) of the
0\nu\beta{\beta} decay transition operator, which are necessary to calculate
the NMEs. This would allow us to extend the ShM calculations for double-beta
decays to larger model spaces, of about 9-10 major harmonic oscillator shells.
The improvement of our code consists in a faster calculation of the radial
matrix elements. Their computation normally requires the numerical evaluation
of two-dimensional integrals: one over the coordinate space and the other over
the momentum space. By rearranging the expressions of the radial matrix
elements, the integration over the coordinate space can be performed
analytically, thus the computation reduces to sum up a small number of
integrals over momentum. Our results for the NMEs are in a good agreement with
similar results from literature, while we find a significant reduction of the
computation time for TBMEs, by a factor of about 30, as compared with our
previous code that uses two-dimensional integrals.Comment: 6 pages, one figur
Rapid method for quantification of anthocyanidins and anthocyanins in human biological samples
This work was performed with the support of āThe Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS),ā Scotland, U.K.Peer reviewedPostprin
Brain metastases of neuroendocrine tumor with unknown primary location: Case report
Neuroendocrine tumors are tumors derived from the cells of the neuroendocrine system. The majority of metastases of neuroendocrine tumors occur in liver, lungs and bone. The brain is an uncommon site of metastasize for this type of tumor. The authors of this paper present a case of brain metastases of neuroendocrine tumor with undetermined primary location. The patient, a 35 years-old man, was admitted in our clinic with headache, nausea, vomiting and a mild right facial paresis. Head CT scan and cerebral MRI identified two lesions: one larger lesion with mixed solid and cystic components located in the left basal ganglia and thalamus and a second cystic lesion located deep in the right parietal lobe. All complementary investigations (including thoracic CT scan and whole-body MRI) failed to reveal the primary tumor location. Due to the high vital-risks associated with the open surgical procedure, the patient and his family chose the less invasive procedure of stereotactic biopsy. Postoperatively the patient had no additional neurologic deficits, presenting only the initial mild right central facial paresis. The result of immunohistochemistry examination was cerebral metastases of neuroendocrine tumor. The patient was directed to the Institute of Oncology Fundeni for further investigations and therapeutically management. In conclusion, even if these are rare tumors which rarely metastasize in the brain, the neurosurgeons should take in consideration this pathology when they examine a patient with multiple cerebral lesions with unknown location of primary tumor
Surgical treatment and outcome of cerebral cavernomas: A 10 yearsā experience
Cavernous malformations (cavernomas) are congenital low flow angiographic occult vascular lesions with a high tencency to bleeding. The prevalence of cerebral cavernous vascular malformations is estimated to be 0.4% to 0.9%.2,7 CMs in deep locations, including the brainstem, thalamus, and basal ganglia, account for 9% to 35% of all malformations in the brain. We performed a retrospective 10 years study on 130 operated cerebral cavernomas and discussed the clinical status at presentation, the choice and timing of the surgical approach and the short and longterm follow up. The 130 operated cases were divided into a supratentorial 102 (78.46%) group and an infratantorial group 28 (21.53%). The average age at presentation was 43,62 years old (17-76) and there was no sex predominance, male/female = 1,44 (77/53). Only in 14 cases (10.76%) we could find multiple cavernomas which had relatives with multiple cavrnomas, but the familial inheritance was not studied, and only the symptomatic lesion was resected. We divided the outcome results reporting for agroup with superficial respectively profound lesions. The long term follow up for the patients in the profound lesions group showed that 31/37 (83,78%) of patients had a mRS between 0 and 2, and the rest had a poor long term outcome. After surgery there was no clinical deterioration in the superficial lesions group and 22 patients from those who presented in mRS 2 showed neurological improvement on long term follow up, meaning that 82,79% of patients had a 0 or 1 mRS. Microsurgery is the treatment of choice in symptomatic brain cavernomas, total resection being the only curative treatment, capable to prevent further bleeding and to offer an efficient control of seizures.Key words: cavernous malformation, microneurosurgery, seizures
Clip reconstruction of a large right MCA bifurcation aneurysm: Case report
We report a case of complex large middle cerebral artery (MCA) bifurcation aneurysm that ruptured during dissection from the very adherent MCA branches but was successfully clipped and the MCA bifurcation reconstructed using 4 Yasargill clips. Through a right pterional craniotomy the sylvian fissure was largely opened as to allow enough workspace for clipping the aneurysm and placing a temporary clip on M1.The pacient recovered very well after surgery and was discharged after 1 week with no neurological deficit. Complex MCA bifurcation aneurysms can be safely reconstructed using regular clips, without the need of using fenestrated clips or complex by-pass procedures
Advanced Scanning Electron Microscopy Methods and Applications to Integrated Circuit Failure Analysis
Semiconductor device failure analysis using the scanning electron microscope (SEM) has become a standard component of integrated circuit fabrication. Improvements in SEM capabilities and in digital imaging and processing have advanced standard acquisition modes and have promoted new failure analysis methods. The physical basis of various data acquisition modes, both standard and new, and their implementation on a computer controlled SEM image acquisition/processing system are discussed, emphasizing the advantages of each method. Design considerations for an integrated, online failure analysis system are also described. Recent developments in the integration of the information provided by electron beam analysis, conventional integrated circuit (IC) testing, computer-aided design (CAD), and device parameter testing into a single system promise to provide powerful future tools for failure analysis
Retrosigmoid approach for a ruptured pontine cavernous malformation, in a 10 years old pacient: Case report
Brainstem cavernous malformations have a high risk of hemorrhage, ranging from 4 to 60%, this risk being even higher in children where larger lesions are encountered. Even small hemorrhages can cause ,severe neurological symptoms because of the high density of cranial nerve nuclei and fiber tracts within the brainstem. The goal of surgical treatment is not only the improvement of neurological symptoms, but also preservation of the patientās quality of life. We present a case of a 10 years old female pacient who presented after a 5 weeks conservative treatment with right sided weakness and loss of coordination, right hemihipoesthesia, She was diagnosed with a large left pontine cavernous malformation on MRI. The cavernoma was resected using a retrosigmoidian approach , but a small remnant was left, when the surgery had to be stopped due to severe bradicardia. The neurological deficit improved at follow up.The choice of the surgical approach that allows the best exposure of the lesion is mandatory. In this case the lesion was evident on the surface of the brainstem and this facilitated its resection. Traction on the tumor and coagulation near the cranial nerves nuclei should be avoided, but if bradicardia appears the surgery must be stopped.Surgery is the best choice for the patients with symptomatic brainstem cavernomas that present with hemorrhage and neurological deficit, and its objectives should be complete removal and improvement of neurological deficit. 
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