Anomalous anisotropic behaviour of spin-triplet proximity effect in Au/SrRuO3/Sr2RuO4 junctions.

Spin-polarized supercurrents can be generated with magnetic inhomogeneity at a ferromagnet/spin-singlet-superconductor interface. In such systems, complex magnetic inhomogeneity makes it difficult to functionalise the spin-polarized supercurrents. However, spin-polarized supercurrents in ferromagnet/spin-triplet-superconductor junctions can be controlled by the angle between magnetization and spin of Copper pairs (d-vector), that can effectively be utilized in developing of a field of research known as superconducting spintronics. Recently, we found induction of spin-triplet correlation into a ferromagnet SrRuO3 epitaxially deposited on a spin-triplet superconductor Sr2RuO4, without any electronic spin-flip scattering. Here, we present systematic magnetic field dependence of the proximity effect in Au/SrRuO3/Sr2RuO4 junctions. It is found that induced triplet correlations exhibit strongly anisotropic field response. Such behaviour is attributed to the rotation of the d-vector of Sr2RuO4. This anisotropic behaviour is in contrast with the vortex dynamic. Our results will stimulate study of interaction between ferromagnetism and unconventional superconductivity.

Challenges of cold chain quality for routine EPI in south-west Burkina-Faso: An assessment using automated temperature recording devices.

BACKGROUND: Abnormal temperatures are a major issue for vaccines within the Expanded Program of Immunization in tropical climates. Prolonged exposure to temperatures outside the standard +2 °C/+8 °C range can impact vaccine potency. METHODS: The current study used automatic temperature recording devices (Testostore 171-1©) to monitor cold chain in remote areas of Western Burkina Faso. A series of 25 randomly selected health centers representing 33% of the existing 176 EPI facilities in Western Burkina Faso were prospectively assessed for eight months in 2015. Automatic measurements were compared to routine temperature loggers and vaccine vial monitors (VVM). RESULTS: The median age for all refrigerators was 9 years with 10/25 (42%) older than 10 years. Adverse temperatures were recorded in 20/24 (83%) refrigerators and ranged from -18.5 °C to +34.2 °C with 12,958/128,905 (10%) abnormal hourly records below +2 °C and 7357/128,905 (5.7%) above +8 °C. Time of day significantly affected the rate of temperature excursions, with higher rates from 00 am to 06 am (p < 0.001) for low temperatures and 10-12 am (p < 0.001) and 13-16 pm (p < 0.001) for high temperatures. Abnormal temperatures lasted from 1 h to 24 h below +2 °C and 13-24 h above +8 °C. Standard manual registers reported only 182/2761 (7%) inadequate temperatures and VVM color change detected only 133/2465 (5%) disruptions. Reliability of the refrigerators ranged from 48% to 98.7% with a median of 70%. Risk factors for excursions were old age of the refrigerators, the months of April and May, hours of high activity during the day, and health staff-associated factors such as inappropriate actions or insufficient knowledge. CONCLUSION: Important cold chain reliability issues reported in the current study in Western Burkina Faso raise concern about vaccine potency. In the absence of systematic renewal of the cold chain infrastructure or improved staff training and monitoring, antibody response assessment is recommended to study levels of effective immunization coverage.

α-Fe2O3 nanotubes-reduced graphene oxide composites as synergistic electrochemical capacitor materials.

We present a facile approach for the fabrication of a nanocomposite comprising α-Fe(2)O(3) nanotubes (NTs) anchored on reduced graphene oxide (rGO) for electrochemical capacitors (ECs). The hollow tubular structure of the α-Fe(2)O(3) NTs presents a high surface area for reaction, while the incorporation of rGO provides an efficient two-dimensional conductive pathway to allow fast, reversible redox reaction. As a result, the nanocomposite materials exhibit a specific capacitance which is remarkably higher (~7 times) than α-Fe(2)O(3) NTs alone. In addition, the nanocomposites show excellent cycling life and large negative potential window. These findings suggest that such nanocomposites are a promising candidate as negative electrodes in asymmetrical capacitors with neutral electrolytes.

Effect of gas pressure on electron field emission from carbon nanotube forests.

This article quantifies the effect of the operating pressure of the H2 + C2H4 gas mixture on the current density and threshold voltage of the electron emission from dense forests of multiwalled carbon nanotubes synthesized using thermal catalytic Chemical Vapor Deposition under near atmospheric pressure process conditions. The results suggest that in the pressure range of interest 400-700 Torr the field emission properties can be substantially improved by operating the process at lower gas pressures when the nanostructure aspect ratios are higher. The obtained threshold voltage approximately 1.75 V/microm and the emission current densities approximately 10 mA/cm2 offer competitive advantages compared with the results reported by other authors.

Molecular dynamics simulation of ZnO nanowires: size effects, defects, and super ductility.

Molecular dynamics simulations of ZnO nanowires under tensile loading were performed and compared with simulations of TiO(2) wires to present size-dependent mechanical properties and super ductility of metal oxide wires. It is shown that while large surface-to-volume ratio is responsible for their size effects, ZnO and TiO(2) wires displayed opposite trends. Although the stiffness of both wires converged monotonically to their bulk stiffness values as diameter increases, bulk stiffness represented the upper bound for ZnO nanowires as opposed to the lower bound for TiO(2) wires. ZnO nanowires relaxed to either completely amorphous or completely crystalline states depending on wire thickness, whereas a thin amorphous shell is always present in TiO(2) nanowires. It was also found that when crystalline ZnO nanowires are stretched, necking initiated at localized amorphous regions to eventually form single-atom chains which can sustain strains above 100%. Such large elongations are not observed in TiO(2) nanowires. Using the analogy of a clothesline, an explanation is offered for the necessary conditions leading to super ductility.

An effective surface-enhanced Raman scattering template based on a Ag nanocluster-ZnO nanowire array.

An effective surface-enhanced Raman scattering (SERS) template based on a 3D hybrid Ag nanocluster (NC)-decorated ZnO nanowire array was fabricated through a simple process of depositing Ag NCs on ZnO nanowire arrays. The effects of particle size and excitation energy on the Raman scattering in these hybrid systems have been investigated using rhodamine 6G as a standard analyte. The results indicate that the hybrid nanosystem with 150 nm Ag NCs produces a larger SERS enhancement factor of 3.2 x 10(8), which is much higher than that of 10 nm Ag NCs (6.0 x 10(6)) under 532 nm excitation energy. The hybrid nanowire arrays were further applied to obtain SERS spectra of the two-photon absorption (TPA) chromophore T7. Finite-difference time-domain simulations reveal the presence of an enhanced field associated with inter-wire plasmon coupling of the 150 nm Ag NCs on adjacent ZnO nanowires; such a field was absent in the case of the 10 nm Ag NC-coated ZnO nanowire. Such hybrid nanosystems could be used as SERS substrates more effectively than assembled Ag NC film due to the enhanced light-scattering local field and the inter-wire plasmon-enhanced electromagnetic field.

Atomistic simulations of inorganic nanowires.

Inorganic nanowires, such as those of metals, semiconductors and oxides, have attracted much research interest due to their unique material properties and present many possibilities for the development of revolutionary applications in materials science and technology. There are abundant reports on experimental works covering various aspects of nanowires including fabrication, structural analysis and property characterization. Theoretical studies have also been carried out to provide researchers with a better understanding of nanowire structural characteristics and the mechanisms that affect their properties. This report gives a brief introduction to the numerical methodologies commonly used for the analysis of nanowires followed by a review of theoretical works focusing on the unique structures of nanowires, their stability and related mechanical properties. The current state of research and development of nanowires is presented together with some comments on the future direction of theoretical studies on inorganic nanowires.

Numerical investigations into the tensile behavior of TiO(2) nanowires: structural deformation, mechanical properties, and size effects.

The mechanisms governing the tensile behavior of TiO(2) nanowires were studied by molecular dynamics simulations. Nanowires below a threshold diameter of about 10 A transformed into a completely disordered structure after thermodynamic equilibration, whereas thicker nanowires retained their crystalline core. Initial elastic tensile deformation was effected by the reconfiguration of surface atoms while larger elongations resulted in continuous cycles of Ti-O bond straightening, bond breakage, inner atomic distortion, and necking until rupture. Nanowires have much better mechanical properties than bulk TiO(2). Nanowires below the threshold diameter exhibit extraordinarily high stiffness and toughness and are more sensitive to strain rate.

Synthesis of "cactus" top-decorated aligned carbon nanotubes and their third-order nonlinear optical properties.

We report a new morphology of "cactus" top-decorated aligned carbon nanotubes grown by the PECVD method using pure C2H2 gas. Unlike most previous reports, no additional carrier gas is used for pretreatment. Carbon nanotubes can still grow and maintain the tubular structure underneath the "cactus" tops. It is proposed that the H atoms produced by the dissociation of C2H2 activate the catalyst nanoparticles. Scanning electron microscopy (SEM) shows that the top "cactus" morphology is composed of a large quantity of small nanosheets. Transmission electron microscopy (TEM) reveals the amorphous carbon nature of these "cactus" structures. The formation of these "cactus" structures is possibly due to covalent absorption and reconstruction of carbon atoms on the broken graphite layers of nanotubes produced by the strong ion bombardment under plasma. The third-order optical nonlinearities and nonlinear dynamics are also investigated. The third-order nonlinear susceptibility magnitude /chi(3)/ is found to be 2.2 x 10(-11) esu, and the relaxation process takes place in about 1.8 ps.

Water-Bridge-Assisted Ionic Conduction in Probe-Induced Conical Polymer Pattern Formation.

Formation of conical polymer structures by atomic force microscopy (AFM) nanolithography and the electrical-conduction mechanism involved in the AFM- probe-induced patterning process are reported. The current is dominated by water-bridge-assisted ionic conduction. Polymer phase transition and mass redistribution occur without modification or degradation of the poly(methyl methacrylate) (PMMA) material.

Fabrication of size-tunable gold nanoparticles array with nanosphere lithography, reactive ion etching, and thermal annealing.

Two-dimensional ordered arrays of gold (Au) nanoparticles were fabricated using two different variants of the nanosphere lithography technique. First, ordered arrays of polystyrene nanospheres on Si substrate were used as deposition masks through which gold films were deposited by electron beam evaporation. After the removal of the nanospheres, an array of triangular Au nanodisks was left on the Si substrate. After thermal annealing at increasing temperature, systematic shape transition of the nanostructures from original triangular Au nanodisks to rounded nanoparticles was observed. This approach allows us to systematically vary the size and morphology of the particles. In the second and novel technique, we made use of reactive ion etching to simultaneously reduce the dimension of the masking nanospheres and create arrays of nanopores on the substrate prior to the deposition of the Au films. These samples were subsequently annealed, which resulted in size-tunable and ordered Au nanoparticle arrays with the nanoparticles nested in the nanopores of the templated substrate. With the nanoparticles anchored in the nanopores, the substrate could be useful as a template for growth of other nanomaterials.

[Early evaluation of surgical treatment for patella fractures]. / Evaluation précoce du traitement chirurgical des fratures de la patella (rotule).

From mars 1989 to mars 1992, 26 fractures of the patella were treated surgically in the "Orthopaedic and Traumatological center in Dakar". We have evaluated the functional and the anatomical results. The mean age of the patients was 45 years. The most common mechanism was direct trauma (24 cases). We have registered 12 opened fractures, 24 displaced fractures and 13 comminutive fractures. Surgical methods were modified tension band internal fixation (18 cases), tension band wiring for fixation (5 cases) and circumferential wire loop fixation (3 cases). The mean follow-up was ten months. Only eight patients have adequate post-operative kinesitherapy. So functional results was poor in 50% of cases. The anatomical reconstruction of the patella were achieved in 18 cases. We have observed a relation between: anatomical results and inadequate indications; excellent functional results and adequate kinesitherapy. So the authors recommend modified tension band internal fixation in transversal fractures and fracture with central communication. Tension band wiring for fixation is used in others comminutive fractures. Post operative kinesitherapy must be realized in a adequate center and criteria of functional evaluation be wider theses.

[Mortality caused by traffic accidents at the Traumatology and Orthopedics Center of Grand-Yoff. A 2-year study. Apropos of 156 cases]. / Mortalité par accident de la voie publique au Centre de Traumatologie et d'Orthopedie de Grand-Yoff. Bilan de deux années. A propos de 156 décès.

Most of road accident casualties are directed to the "Centre de Traumatologie et d'Orthopedie" between March 1989 and March 1991, the emergency Department received 8250 casualties treated by a team core comprising anesthetist-intensive care doctors and orthopaedic surgeons supplemented when necessary by other specialists. Out of those 8250 casualties aged 30 in average, 156 died at the hospital in varying time limits. The authors of present study intend to assess the efficiency of the medical and surgical care provided to identify the most frequent death causes and to suggest ways means of reducing the death toll. Forensic autopsies revealed the following lesions by order of prevalence: brain traumas 68, polytraumatisms 58, cervical vertebral traumas 13, abdomen traumas 7, polyfractures 3. In despite of the working conditions improvement at this specialized center (intensive care, technical facilities and staff) the mortality rate remains high, specially in polytraumatisms and brain traumas. The authors insist upon the need for a medically assisted transport unit which would take care of casualties before their arrival at hospital and for the acquisition of modern diagnosis means (tomodensitometry).

[Osteosynthesis of displaced fractures of the acetabulum with Letournel plate. Apropos of 14 cases]. / Ostéosynthèse des fractures déplacées du cotyle par plaque de Letournel. A propos de 14 cas.

Up to 1989, conservative treatment was used for fractures of the acetabulum at the Dakar teaching hospital, with in previous study, of poor result. The same authors present here their first experience of surgical treatment of displaced fractures of acetabulum using LETOURNEL plate at the "Centre de Traumatologie" of Dakar for three years. Fourteen patients (12 men and 2 women) presented after traffic road accident: fracture of posterior wall: 7 cases transversal fracture: 1 case complex fractures: 6 cases. Those displaced fractures were associated with hip dislocation in 8 cases. The initial emergency treatment by reducing the dislocation, associated with transfemoral pin traction was realized. At the day 7 through a posterior surgical approach in 11 cases and through a combined anterior and posterior approach in three cases. The anatomical reconstruction of the acetabulum was achieved in 12 cases. It's still early to make a final clinical assessment, but the early functional results using MERLE D'AUBIGNE's criteria (pain, lamenliss, mobility) are very good in 10 cases and poor in 2 cases. The reliability of the procedure, and the adequate post operative kinesitherapy is according to the authors the main indication for displaced fractures of the acetabulum.

[Sacro-ilial tuberculosis (sacrococcygeal). Apropos of 1 case]. / Sacro-ileite tuberculeuse (sacro-coxalgie). A propos d'un cas.

In a single case review the authors recapitulate the different methods for the presentation of sacro-ilial infectious and underscore imagery techniques which are of prime importance in diagnostic work. X-rays can only reveal advanced sacro-ilial bone joint lesions which are under-evaluated. In the absence of HI-Tech imagery, surgical biopsy must be widely recommended to identify the germ and allow early diagnosis.