Tetanus in Libreville: hospital analysis of 30 cases]

The aim of this study was to compare different muscle contraction types in Parkinson patients and controls. Ten patients with mild to moderate Parkinsonism (7 men, 3 women, mean age 62.3) and 11 controls (7 men, 4 women, mean age 66.0) were investigated. Measurements in eccentric, concentric contraction and stretch-shortening contraction were made using modified Cybex 11 equipment. The torque areas in ankle dorsiflexors at 30 degrees/second, 120 degrees/second and 180 degrees/second were measured. The power (Nm/second) was calculated in a defined range of motion. The power at different angular velocities and contraction types was significantly lower in the patient group than in the control group. In both groups the power in eccentric and stretch-shortening contraction was significantly larger than in concentric contraction. The relative improvement in power in stretch-shortening contraction in patients was equal to the improvement made by the controls. Patients generated significantly more EMG than controls in concentric and eccentric contractions. The EMG in the stretch-shortening cycle was the same in both groups at higher velocities. The patients performed voluntary isolated muscle contraction in the same way as controls, but with a lower efficiency in contraction. The eccentric torque and the supplement of torque generated from the combined eccentric and concentric (stretch-shortening) contraction might be important for achievement of adequate dynamic movements in patients with Parkinson's disease.     

Glucose transporters in rat peripheral nerve: paranodal expression of GLUT1 and GLUT3

Peripheral nerve depends on glucose oxidation to energize the repolarization of excitable axonal membranes following impulse conduction, hence requiring high-energy demands by the axon at the node of Ranvier. To enter the axon at this site, glucose must be transported from the endoneurial space across Schwann cell plasma membranes and the axolemma. Such transport is likely to be mediated by facilitative glucose transporters. Although immunohistochemical studies of peripheral nerves have detected high levels of the transporter GLUT1 in endoneurial capillaries and perineurium, localization of glucose transporters to Schwann cells or peripheral axons in vivo has not been documented. In this study, we demonstrate that the GLUT1 transporter is expressed in the plasma membrane and cytoplasm of myelinating Schwann cells around the nodes of Ranvier and in the Schmidt-Lanterman incisures, making them potential sites of transcellular glucose transport. No GLUT1 was detected in axonal membranes. GLUT3 mRNA was expressed only at low levels, but GLUT3 polypeptide was barely detected by immunocytochemistry or immunoblotting in peripheral nerve from young adult rats. However, in 13-month-old rats, GLUT3 polypeptide was present in myelinated fibers, endoneurial capillaries, and perineurium. In myelinated fibers, GLUT3 appeared to be preferentially expressed in the paranodal regions of Schwann cells and nodal axons, but was also present in the internodal aspects of these structures. The results of the present study suggest that both Schwann cell GLUT1 and axonal and Schwann cell GLUT3 are involved in the transport of glucose into the metabolically active regions of peripheral axons.     

Mikrowelleninduzierte Thermolyse von Erdöl unter der Einwirkung von heterogenen Katalysatoren

The first oil‐producing regions in the human history were located near Baku. Until the beginning of the 20th century, the Balachany‐Sabuncu‐Ramany region produced more than 60 % of Baku's oil. This oil sources are largely exploited and contain yet only heavy extractable fractions of crude oil. Experiments with oil samples from this oil fields show, that irradiation with microwaves under addition of magnetite catalysts leads to a reduction of petroleum viscosity. It seems to be a new attempt for intensive extraction of petroleum.     

Energy-spectral efficient resource allocation and power control in heterogeneous networks with D2D communication

Wireless Networks - Heterogeneous networks (HetNets) provide the demand for high data rates. In this study, we analyze the coexistence of femtocells and device-to-device (D2D) communication with...     

Multi-objective algorithms for the application mapping problem in heterogeneous multiprocessor embedded system design

The Journal of Supercomputing - Design at the Electronic System-Level tackles the increasing complexity of embedded systems by raising the level of abstraction in system specification and modeling....     

Influence of graphene nanoplatelet incorporation and dispersion state on thermal,mechanical and electrical properties of biodegradable matrices

Graphene nanoplatelets (GNPs) were used as multifunctional nanofiller to enhance thermal and mechanical properties as well as electrical conductivity of two different biodegradable thermoplastics: poly lactide (PLA) and poly (butylene adipate-co-terephthalate) (PBAT). Morphological investigations showed different levels of GNP dispersion in the two matrices, and consequently physical properties of the two systems exhibited dissimilar behaviours with GNP incorporation. Crystallinity of PLA, determined from differential scanning calorimetry, was observed to increase markedly with addition of GNPs in contrast to the decrease in crystallinity of PBAT. Isothermal and non-isothermal thermogravimetric analyses also revealed a more significant delay in thermal decomposition of PLA upon addition of GNPs compared to that of PBAT. Furthermore, results showed that increasing GNP content of PLA and PBAT nanocomposites influenced their Young’s modulus and electrical conductivity in different ways. Modulus of PBAT increased continuously with increasing GNP loading while that of PLA reached a maximum at 9 wt% GNPs and then decreased. Moreover, despite the higher conductivity of pure PBAT compared to pure PLA, conductivity of PLA/GNP nanocomposites overtook that of PBAT/GNP nanocomposites above a certain GNP concentration. This demonstrated the determining effect of nanoplatelets dispersion state on the matrices properties.     

Multi-objective shape design optimization of piezoelectric energy harvester using artificial immune system

Energy harvesting is about deriving energy from environment and converting into electricity. In this paper, optimal design of a cantilever piezoelectric energy harvester is presented with the aim to capture electrical power from a vibratory feeder in mining industry. Rayleigh–Ritz method is utilized for the modeling of the cantilever piezoelectric, taking into account possible variation in the width, nonequivalent layer lengths and thickness for unimorph and bimorph configurations. Innovatively, intelligent artificial immune system is utilized for multi-objective optimization of the shape parameters of the system. To verify the presented analytical shape optimization method, finite element analysis of the designed system is also presented, to investigate the output voltage and stress distribution along the piezoelectric layer. Moreover, the experimental setup is generated and verification tests are performed to derive frequency response diagram of the system. The obtained results are encouraging, indicating good agreement between experiments, FE analysis and theoretical results.     

Effect of magnesium and sulfate ions on durability of silica fume blended mixes exposed to the seawater tidal zone

The effect of silica fume on deterioration resistance to sulfate attack in seawater within tidal zone and simulated wetting-drying condition has been studied in Portland cement concretes and pastes containing silica fume (SF) with/without ground granulated blast furnace slag (GGBS). Changes in the compressive strength and capillary water absorption of specimens as a function of SF content have been investigated combined with phases determination by means of scanning electron microscopy and X-ray energy dispersion analysis. The strength change factors (SCFs) of specimens with SF (the more SF content, the higher strength loss) were greater than that of the mixes without SF or cured under tap water. Mg²⁺ ion originated attack found to be the dominating deterioration mechanism as confirmed by X-ray and chemical analyses.Further, the incorporation of GGBS with SF mixes in different exposure conditions led to the worst performance in all of the test environments. Lower cement content and hydration rate accompanied with particular chemical composition of GGBS made concrete and paste specimens to be more susceptible to deleterious seawater environment.     

Compact ultra‐wideband bandpass filter with variable notch characteristics based on transversal signal‐interaction concepts

A novel technique is presented to design highly compact microstrip ultra‐wideband (UWB) bandpass filters that exhibit high selectivity quasi‐elliptical response. The design is based on transversal signal‐interaction concepts that enable the inclusion of single or dual notch‐bands within the filter's passband to eliminate interference from other services that coexist within the UWB spectrum. The filter configuration comprises of two transmission paths which include folded T‐shaped stepped impedance resonators (SIRs) that are capacitively coupled with the input/output lines to enable signal transmission. It is shown that by combining the filters of different passband centre frequencies an UWB filter can be realised with either a single‐ or dual‐notch function. The theoretical performance of the filter is corroborated via measurements to confirm that the proposed filter exhibits UWB passband of 123% for a 3 dB fractional bandwidth, a flat group‐delay with maximum variation of less than 0.3 ns, passband insertion loss less than 0.94 dB, high selectivity, a sharp rejection notch‐band with attenuation of ?23 dB, and a good overall out‐of‐band performance. Furthermore, the filter occupies a significantly small area of 94 mm² compared with its classical counterparts. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:549–559, 2014.     

Improved passivity criterion in haptic rendering: influence of Coulomb and viscous friction

In this paper, a new criterion for passivity of haptic devices is obtained. This criterion creates a relationship between Coulomb friction coefficient, viscous friction coefficient, sampling rate, and the maximum simulated stiffness. The process of derivation of the passivity criterion is described in detail. This criterion is improved compared with other existing criteria and predicts passivity in haptic rendering more accurately. In particular, for speeds of less than 5?cm/s, the new passivity criterion should replace the previous criteria to avoid unwanted vibrations of stiff virtual walls. Analytical and numerical investigations are presented to validate the new criterion. A specific trajectory is designed and the movement of the haptic robot is investigated on this trajectory to validate and compare this passivity criterion with the previous criteria.