Hysteresis in a magnetic bead and its applications

We study hysteresis in a micron-sized bead: a non-magnetic matrix embedded with super- paramagnetic nanoparticles. These hold tremendous promise in therapeutic applications as heat generating machines. The theoretical formulation uses a mean-field theory to account for dipolar interactions between the supermoments. The study enables manipulation of heat dissipation by a compatible selection of commercially available beads and the frequency f and amplitude ho of the applied oscillating field in the labortory. We also introduce the possibility of utilizing return point memory for gradual heating of a local region.Comment: 8 pages, 4 figure

Web-enabled Intelligent System for Continuous Sensor Data Processing and Visualization

A large number of sensors deployed in recent years in various setups and their data is readily available in dedicated databases or in the cloud. Of particular interest is real-time data processing and 3D visualization in web-based user interfaces that facilitate spatial information understanding and sharing, hence helping the decision making process for all the parties involved. In this research, we provide a prototype system for near real-time, continuous X3D-based visualization of processed sensor data for two significant applications: thermal monitoring for residential/commercial buildings and nitrogen cycle monitoring in water beds for aquaponics systems. As sensors are sparsely placed, in each application, where they collect data for large periods (of up to one year), we employ a Finite Differences Method and a Neural Networks model to approximate data distribution in the entire volume

Trends and perspectives of the Romanian regional passenger transport

Today, passenger transport has become an indispensable life element, because it offers to the society members many travel possibilities. Modern civilisation, characterised by a massive trade of material and spiritual values, claims a continuous movement of goods and people from a place to another. Transport services are strongly influenced by the transition to the market economy, Romania’s geographical position and also by the life standard. The purpose of this paper is to realize a statistical analysis of the main indicators concerning passenger transport for the southern part of Romania, respectively for the historical provinces Muntenia (excluding Bucharest Municipality) and Oltenia

Large and giant vestibular Schwannomas

Background: The main objective in treating large and giant vestibular schwannomas (VS) (large - diameter exceeding 3.5 cm and giant - diameter exceeding 4.5 cm) is their complete removal without significant morbidity. Our experience on 7 cases (4 females, 3 males, mean age 42.5 years) with marked brainstem compression, operated between 2004-2009 focuses on factors influencing recurrence and morbidity, especially related to facial nerve function. These patients were included in a series of 32 consecutive vestibular schwannoma excisions.Methods: This report is a retrospective analysis of the surgical outcome of 7 patients with large and giant VS using the retrosigmoid-transmeatal approach. Several prognostic factors were evaluated: patient age, tumor size and consistency, extent of surgical removal, concurring hydrocephalus, hearing loss, facial nerve function, trigeminal nerve deficits, cranial nerve VI, IX and X palsy, tongue edema, ataxic gait and motor deficits.Results: The mean age was 42.3 years, the mean tumor diameter was 51.8 mm. There were no deaths and the tumors were histologically benign. Extensive microscopic tumor resection was performed in 5 cases related to solid tumor’s consistency. Preoperatively hearing loss and high intracranial pressure were encountered in all patients. 4 patients had cerebellar ataxia. Facial anatomical continuity was preserved in 6 cases with solid tumor consistency; 4 patients had a preoperative facial palsy, a good facial nerve function was achieved in 3 cases – House-Brackmann grade I/II. We have met other distinctive signs: cranial nerve V hypoesthesia, VI, IX and X palsy, tongue edema in 2 cases with slight contralateral motor deficit. All patients were clinical and MRI monitored at 3, 6 and 12 months postoperatively.Conclusion: Total resection associated with a low morbidity rate is possible, avoiding recurrence, reintervention and severe scar tissue. In cases with subtotal resection, radiosurgery is recommended to improve outcome

Personal experience in lumbar spinal stenosis (LSS)

Objective: To investigate the effectiveness of our strategy in lumbar spinal stenosis. This is based on the following: precise clinical radicular description of the level of claudication by electrodiagnosis, fine neuroradiologic studies, microsurgical decompression, assessment of the factors which might influence the outcome.Methods: The study was performed on 145 patients who underwent decompression in the last 8 years: 95 males, 50 females, mean age 65 yrs (50-81). Comorbidities were carefully considered when choosing the surgical procedure, especialy in elderly patients; an initial conservative approach of 3 weeks was used for most patients. Concerning etiology: 105 were degenerative, 16 post trauma, 24 others. Our cases included: 48 cases of single, focal stenosis, 97 diffuse (52 cases in 2 levels and 45 cases in 3 or more levels); 50% were graded as severe and evolved within 6 weeks, 30% were graded severe to moderate and 20% were moderate after a 2 month evolution; 15 were central, 17 lateral, 13 foraminal and 100 mixed. Precise clinical radicular description of the level of claudication by electrodiagnosis was used in all patients, MRI studies – 115 patients, CT studies - 30 patients, plain static x-rays of lumbar spine, dynamic flexion and extension x-rays of lumbar spine – all patients; disability degree evaluation: Oswestry Disability Index, pain (visual analog scale and analgesic consumption), functional improvement (Neurogenic Claudication Outcome Score), walking performance and instability degree (Pre-op and intraoperative) to all patients.We used a 4-5 cm incision for focal stenosis, 5-10 cm incision for 2-3 levels, C-arm for localization, high speed drill, cutting and diamond burrs, microscope, microinstruments, fenestration and medial facet undercutting to ensure an adequate root decompression. We excised the ligamentum flavum in the lateral recess which is often thickened. The lower lateral 6-12 mm of the lamina above and/or the superior lateral 3-9 mm of the lamina below were also resected to expose the root, the disc was excised and the posterior osteophytes were chiseled away with a fine micro chisel or diamond drill. In cases of focal stenosis we performed: foraminotomy, laminotomy, osteophytectomy, ligamentum flavectomy; diffuse/multilevel stenosis was approached as follows: laminotomies, foraminotomies, osteophytectomy, ligamentum flavectomy, medial facetectomy, fusion. In 24 cases we attempted a pedicle screw fixation and in two cases Diam devices. No re-do surgery was required.Results: One week after surgery, pain decreased in 87.9% of patients; nonsteroidal anti- inflammatory drug consumption and analgetics decreased in 81%. Two years after surgery, pain remained decreased in 79.8% of patients, Neurogenic Claudication Outcome Score decreased in 78.7% of patients and walking performance improved in 97.2% of patients. Patients who underwent both multilevel decompression or single - level decompression benefitted. Conclusions: LSS surgery is functional, never preventive; the initial management should be non-surgical except for severe cases. Electrophysiological testing correlated with thorough neurological examination is more accurate than a radiological evaluation alone when choosing the roots to be decompressed. Microsurgical selective decompression accomplishes a good balance between bony and soft tissue decompression, while also maintaining spinal stability