Phase Diagrams and Crossover in Spatially Anisotropic d=3 Ising, XY Magnetic and Percolation Systems: Exact Renormalization-Group Solutions of Hierarchical Models

Hierarchical lattices that constitute spatially anisotropic systems are introduced. These lattices provide exact solutions for hierarchical models and, simultaneously, approximate solutions for uniaxially or fully anisotropic d=3 physical models. The global phase diagrams, with d=2 and d=1 to d=3 crossovers, are obtained for Ising, XY magnetic models and percolation systems, including crossovers from algebraic order to true long-range order.Comment: 7 pages, 12 figures. Corrected typos, added publication informatio

Design and implementation of a DMD based volumetric 3D display

A real image swept-volume volumetric display is developed. A piston type moving screen is used to obtain the desired volume. A commercially available DMD device is used to project 2D slices of a 3D frame. There is a varying magnification effect during the projection because of the optical design of the system; raw 3D video frames are processed by a software to generate the appropriate 2D slices by also correcting the magnification. Synchronization between the hardware and the software is achieved via a microcontroller. The overall system is capable of printing 12 3D frames per second where a 3D frame consists of 90 2D slices with a resolution varying from 512x512 to 450x450 (approx. 20M voxels per one 3D frame). Although some flickering effect is observed due to rather low 3D frame rate, results are visually satisfactory. ©2008 IEEE

Pathologic assessment of non-palpable probably benign breast masses at sonography: can instant intervention be avoided and is follow-up adequate?

Aim of the study: To evaluate the pathologic results, determine the negative predictive value of non-palpable probably benign lesions at ultrasound and asses whether follow-up is adequate and immediate biopsy can be avoided. Materials and methods: Four hundred and eight cases which were referred to our breast imaging unit between 2004 and 2008 for biopsy evaluation were enrolled into the study. Two hundred and thirteen probably benign solid masses are classified as BI-RADS 3 in 205 of the enrollees. All masses were sonographically detectable and were classified through the guidelines of BI-RADS lexicon for sonography before the final pathological examination. All pathologic results were evaluated and the negative predictive value, false negativity rate and 95% confidence interval were calculated. Results: Of the 213 masses, fine needle aspiration cytology was performed in 120. US-guided wire localization and eventual surgery were carried out in the remaining 93 masses. Finally, 211 of the punctured lesions turned out to be benign and only two malignant lesions were detected. The resulting negative predictive value was found to be 99.1% while the false negative rate value was 0.9%. Conclusion:With the results provided, we think that in the patients with sonographically detected probably benign breast lesions, short term follow-up seems to be a strong alternative to immediate biopsy with its reliable high negative predictivity as well as low false negativity

The HELLP syndrome: Clinical issues and management. A Review

<p>Abstract</p> <p>Background</p> <p>The HELLP syndrome is a serious complication in pregnancy characterized by haemolysis, elevated liver enzymes and low platelet count occurring in 0.5 to 0.9% of all pregnancies and in 10–20% of cases with severe preeclampsia. The present review highlights occurrence, diagnosis, complications, surveillance, corticosteroid treatment, mode of delivery and risk of recurrence.</p> <p>Methods</p> <p>Clinical reports and reviews published between 2000 and 2008 were screened using Pub Med and Cochrane databases.</p> <p>Results and conclusion</p> <p>About 70% of the cases develop before delivery, the majority between the 27th and 37th gestational weeks; the remainder within 48 hours after delivery. The HELLP syndrome may be complete or incomplete. In the Tennessee Classification System diagnostic criteria for HELLP are haemolysis with increased LDH (> 600 U/L), AST (≥ 70 U/L), and platelets < 100·10⁹/L. The Mississippi Triple-class HELLP System further classifies the disorder by the nadir platelet counts. The syndrome is a progressive condition and serious complications are frequent. Conservative treatment (≥ 48 hours) is controversial but may be considered in selected cases < 34 weeks' gestation. Delivery is indicated if the HELLP syndrome occurs after the 34th gestational week or the foetal and/or maternal conditions deteriorate. Vaginal delivery is preferable. If the cervix is unfavourable, it is reasonable to induce cervical ripening and then labour. In gestational ages between 24 and 34 weeks most authors prefer a single course of corticosteroid therapy for foetal lung maturation, either 2 doses of 12 mg betamethasone 24 hours apart or 6 mg or dexamethasone 12 hours apart before delivery. Standard corticosteroid treatment is, however, of uncertain clinical value in the maternal HELLP syndrome. High-dose treatment and repeated doses should be avoided for fear of long-term adverse effects on the foetal brain. Before 34 weeks' gestation, delivery should be performed if the maternal condition worsens or signs of intrauterine foetal distress occur. Blood pressure should be kept below 155/105 mmHg. Close surveillance of the mother should be continued for at least 48 hours after delivery.</p

Obstructive sleep apnea secondary to cervical spine chordoma

We present a rare case of obstructive sleep apnea (OSA) secondary to chordoma involving cervical spine with confirmative histopathological diagnosis following the suggestive findings of computed tomography and magnetic resonance imaging. The patient underwent en bloc removal of the tumour involving the vertebral body of C4 with preservation of the nerve roots and vertebral arteries involved, associated with postoperative radiation therapy. Clinicians should be aware that this is a very rare secondary cause of OSA caused by chordoma involving the spine and imaging of the cervical spine may be necessary to avoid incorrect treatment approaches such as CPAP or BiPAP machine in such cases. Keywords: Chordoma, Radiotherapy, Surgery, Tumou