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

Atomic-scale confinement of optical fields

In the presence of matter there is no fundamental limit preventing confinement of visible light even down to atomic scales. Achieving such confinement and the corresponding intensity enhancement inevitably requires simultaneous control over atomic-scale details of material structures and over the optical modes that such structures support. By means of self-assembly we have obtained side-by-side aligned gold nanorod dimers with robust atomically-defined gaps reaching below 0.5 nm. The existence of atomically-confined light fields in these gaps is demonstrated by observing extreme Coulomb splitting of corresponding symmetric and anti-symmetric dimer eigenmodes of more than 800 meV in white-light scattering experiments. Our results open new perspectives for atomically-resolved spectroscopic imaging, deeply nonlinear optics, ultra-sensing, cavity optomechanics as well as for the realization of novel quantum-optical devices

Rapid method for quantification of anthocyanidins and anthocyanins in human biological samples

This work was performed with the support of “The Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS),” 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 years’ 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

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 patient’s 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.&nbsp