Two-Body Density Matrix for Closed s-d Shell Nuclei

The two-body density matrix for $^{4}He,^{16}O$ and $^{40}Ca$ within the Low-order approximation of the Jastrow correlation method is considered. Closed analytical expressions for the two-body density matrix, the center of mass and relative local densities and momentum distributions are presented. The effects of the short-range correlations on the two-body nuclear characteristics are investigated.Comment: 13 pages(LaTeX), 4 figures (ps

Advances in surface EMG signal simulation with analytical and numerical descriptions of the volume conductor

Surface electromyographic (EMG) signal modeling is important for signal interpretation, testing of processing algorithms, detection system design, and didactic purposes. Various surface EMG signal models have been proposed in the literature. In this study we focus on 1) the proposal of a method for modeling surface EMG signals by either analytical or numerical descriptions of the volume conductor for space-invariant systems, and 2) the development of advanced models of the volume conductor by numerical approaches, accurately describing not only the volume conductor geometry, as mainly done in the past, but also the conductivity tensor of the muscle tissue. For volume conductors that are space-invariant in the direction of source propagation, the surface potentials generated by any source can be computed by one-dimensional convolutions, once the volume conductor transfer function is derived (analytically or numerically). Conversely, more complex volume conductors require a complete numerical approach. In a numerical approach, the conductivity tensor of the muscle tissue should be matched with the fiber orientation. In some cases (e.g., multi-pinnate muscles) accurate description of the conductivity tensor may be very complex. A method for relating the conductivity tensor of the muscle tissue, to be used in a numerical approach, to the curve describing the muscle fibers is presented and applied to representatively investigate a bi-pinnate muscle with rectilinear and curvilinear fibers. The study thus propose an approach for surface EMG signal simulation in space invariant systems as well as new models of the volume conductor using numerical methods

Clinical Case of a Child with Optic Neuritis, Associated with Epstein-Barr Virus

We present a clinical case of a child with bilateral papillitis, associated with EBV-infection in a 5-year-old female child, who was diagnosed and treated at the Aleksandrovska University Hospital. The initial reason for the eye-exam was a new-onset squint. On admission, she had discrete Eidon confocal scan, decreased visual acuity and bilateral edema and hyperemia of the optic disks. MRI of brain and orbits was evaluated on emergency to rule out a demyelinating or intracranial process. The child had persistent lymphadenopathy and laboratory abnormalities and tested positive for EBV serology. She was treated with intravenous corticosteroid pulse therapy and visual acuity was restored to 100%. Papillitis in children is frequently bilateral, with viral genesis and has a good prognosis. Isolated papillitis (without inflammation of other eye structures) is difficult to distinguish clinically from papilledema. When papilledema is suspected, urgent MRI has to be carried out

Normal tension glaucoma – case report

Normal tension glaucoma (NTG), reffered to also as low-tension glaucoma, represents a glaucomatous optic neuropathy classified as a type of Primary open angle glaucoma (POAG). It is characterized by a higher tendency of damage to the optic nerve at relatively low levels of intraocular pressure (IOP), as well as asymmetric pathological process in both eyes of the same patient. A number of IOP-independent factors play a significant role in the progression of the disease and often lead to difficulties in diagnosis and optimal therapy in these patients. We report a typical clinical case of a patient with NTG

Retinoblastoma – a literature review and our experience

Retinoblastoma is the most common malignant eye tumor in children that is lethal if left untreated. The contemporary treatment modalities aim not only to save life, but also to preserve the eyes as an organwith form vision and the wich would greatly reflect on the quality of children’s lives. Historically, enucleation was the first successful therapeutic approach to reduce mortality, followed more than 100 years ago by the radiation therapy as the first attempt to save the eyes. Over the last two decades, conservative treatment of retinoblastoma has undergone an impressive development, allowing complete cure with minimal sequelae when timely diagnosed and treated. Today’s treatment protocol includes combination of selective chemotherapy, radiation therapy, laser therapy and, if necessary, systemic chemotherapy. The goal of this article is to review the up-to-date conservative management of retinoblastoma and to emphasize the importance of general practitions and pediatricians for timely diagnosis

Laser therapy in ROP: a literature review and our experience

Introduction: Retinopathy of prematurity (ROP) is a serious, vision threatening disease and among the leading causes of irreversible loss of vision. It affects prematurely born children, predominantly prior to the 32nd GW or with a body weight at birth below 1500 g. The highest risk for the development of ROP includes the time period of two weeks before to two weeks after the supposed due date. Materials and Methods: We included 10 prematurely born children with ROP requiring therapy. All of the children were screened by indirect ophthalmoscopy and the condition was documented by RetCam imaging. The treatment was conducted by the application of 810 nm diode laser. Results: Nine out of the 10 children were born before 32 GW and were with a body weight at birth below 1500 g. The disease was bilateral in 9 of the children. Laser therapy was applied to all 10 children and 18 eyes. Discussion and Conclusion: The active ophthalmological screening of all children born before 32 GW and with a body weight at birth below 1500 g, including all new-born children at risk, and the application of early laser treatment are the basis for the prevention of the development of irreversible visual loss

Atypical suamous papilloma of the conjunctiva

Papillomas are benign tumors of human skin and mucous membranes caused by human papillomavirus (HPV). The virus causes abnormal epithelial cell growth. The formations vary in shape, size and location. The conjunctival papillomas are one of the most common benign tumors of the squamous epithelium of the conjunctiva. They rarely undergo malignant transformation. Purpose: To present a clinical case with proven atypical squamous papilloma of the conjunctiva. Materials: 58-year-old patient was admitted to the Eye Clinic of University Alexandrovska hospital for the first time. Methods: A complete ophthalmologic examination, ultrasonography, surgery and pathohistological diagnosis were performed. Results: Thorough excision of the tumor lesion in healthy tissue was performed. The pathological diagnosis revealed atypical squamous papilloma of the conjunctiva. Conclusion: The diagnosis can only be confirmed pathohistologically. A good relationship between ophthalmologist and pathologist is necessary for the successful diagnosis and subsequent treatment