Cerebellar dysgenesis in rats by diaplacental effects of 7,12-dimethylbenz[a]anthracene

7,12-Dimethylbenz[a]anthracene (DMBA) administered iv to pregnant Sparague-Dawley rats produced cerebellar malfunction in at least 10% of the offspring. The underlying morphologic basis of the cerebellar symptomatology was found in maldevelopment of cerebellar cortex, ranging from focal loss of granule and Purkinje's cell layers to extensive areas of cortical disorganization with losses of granule neurons. An interference with the proliferation of the granule cell-layer primordium was suggested as a mechanism of this cerebellar dysgenesis. After a 200-day observation, no tumors were found in the offspring of the DMBA-treated, pregnant rats.     

Pulmonary sequestration associated with a gastric duplication cyst

A case of right subdiaphragmatic extralobar pulmonary sequestration (PS) associated with a gastric duplication cyst is reported. To the authors' knowledge such a case has not been reported previously in the English literature. PS was first noted as a defect on a nuclear liver image. The duplication cyst was defined by ultrasonography. A review of the English literature is included.     

Determination of InN/Diamond Heterojunction Band Offset by X-ray Photoelectron Spectroscopy

Diamond is not only a free standing highly transparent window but also a promising carrier confinement layer for InN based devices, yet little is known of the band offsets in InN/diamond system. X-ray photoelectron spectroscopy was used to measure the energy discontinuity in the valence band offset (VBO) of InN/diamond heterostructure. The value of VBO was determined to be 0.39 ± 0.08 eV and a type-I heterojunction with a conduction band offset (CBO) of 4.42 ± 0.08 eV was obtained. The accurate determination of VBO and CBO is important for the application of III-N alloys based electronic devices.     

In vitro simulation. Early results of stereotaxy for pedicle screw placement

STUDY DESIGN: Frameless stereotaxy with doppler ultrasound and three dimensional computer model registration is assessed in vitro for pedicle screw placement. OBJECTIVE: To identify feasibility of pedicle screw navigation and placement using this technology. SUMMARY OF BACKGROUND DATA: Inaccurate pedicle screw placement can lead to neurovascular injury or suboptimal fixation. Present techniques in pedicle screw placement involve only confirmation of hole orientation. METHOD: Forty-four pedicle screws were placed in lumbosacral models and cadaver specimens. Accuracy was assessed with a computed tomography scan and vertebral cross sectioning. RESULTS: All screws were intrapedicular. Accuracy of anterior cortical fixation was 1.5 mm, with a range of 2.5 mm. CONCLUSION: In vitro frameless stereotaxy is accurate for pedicle screw placement. This technology adds a component of navigation to pedicle screw placement.     

Reduced NOx and PM10 emissions on urban motorways in The Netherlands by 80 km/h speed management

A speed limit of 80 km/h with “strict enforcement” has been introduced in 2005 on zones of urban motorways in The Netherlands with the aim to improve air quality of NO₂ and PM₁₀ along these motorways. Strict enforcement means speed control by camera surveillance over the whole trajectory of 2-4 km combined with licence plate recognition and automatic fining in case of exceeding the speed limit. Traffic data measured in Rotterdam and Amsterdam at the zones without and with speed management showed that traffic dynamics have been significantly reduced as a result of speed management with strict enforcement. Reduction of traffic dynamics results in more free-flowing traffic with relatively less NO_x and exhaust PM₁₀ emissions compared to congested traffic, i.e., stop-and-go traffic.The actual effect on NO_x and PM₁₀ emissions at these speed management zones was studied in the cities Rotterdam and Amsterdam. The study was performed in two different ways: firstly by measurements and by modelling the contribution to NO_x and PM₁₀ concentrations on both sides of the motorways, and secondly by estimating the change in traffic dynamics and the effect on emissions. From the results of both approaches in this study, it was concluded that in our case study in the Netherlands emission reduction by speed management is in the range of 5-30% for NO_x and 5-25% for PM₁₀. Actual emission reductions by speed management at a specific motorway mainly depend on the ratio of congested traffic prior and after implementation of speed management. The larger this ratio, the larger is the relative emission reduction. The impact on air quality of 80 km/h for NO_x and PM₁₀ is largest on motorways with a high fraction of heavy-duty vehicles.     

AN ATTRIBUTION OF CAVITATION RESONANCE： VOLUMETRIC OSCILLATIONS OF CLOUD

In order to further verify the proposed theory of cavitation resonance, as well as to proceed the investigations into microscopic level, a series of studies are being carried out on the Warwick venturi. The analysis of the oscillation characteristics of the cavitation resonance has conclusively verified the macro-mechanism proposed through previous studies on other cavitating flows by the authors. The initial observations using high-speed photographic approach have revealed a new attribution of cavitation resonance. That is, the volumetric oscillation of cavitation cloud is associated with the cavitation resonance, which is a collective behaviour of the bubbles in the cloud.     

MODIFIED SLIDING MODE (MSM) VERSUS PI SPEED CONTROL OF A CURRENT-CONTROLLED FIELD-ORIENTED INDUCTION MOTOR DRIVE

ABSTRACT

This paper describes the dynamic performance of a new, modified sliding mode (MSM), speed control system for an existing current-controlled field-oriented induction motor drive with rather robust rotor flux estimator.

Extensive digital simulations and some test results prove the superiority of IBM versus PI in terms of reduced speed overshooting, response quickness, and robustness to rotor resistance variation. The rotor flux estimator amplitude and phase error during severe transients has also been investigated through digital simulations.     

Application of Landsat Thematic Mapper data in sabkha studies at the Red Sea coast

Salt-enriched flat areas are known as sabkhas in the Red Sea coasts. Previously classified sabkhas north of Jeddah city, Saudi Arabia were examined by remote sensing techniques. Confirmation of ground studies was reached with the synoptic coverage and spectral characteristics of the Landsat digital data. New maps were produced utilizing satellite data; this may include geomorphological and sabkha zonation maps. False colour, ratio and principal components composites were used in this study by image analysis system. Three main parameters, i.e., moisture content and its salinity, salt content and water-table level are exhibiting themselves as different colours in the coloured images. The approach described herein is recommended to be applied along the Red Sea coasts and other similar areas in order to present a preliminary but precisely identification of sabkha environments utilizing remote sensing techniques.