Plasmon-Enhanced Light Absorption in (p-i-n) Junction GaAs Nanowire Solar Cells: An FDTD Simulation Method Study.

A finite-difference time-domain method is developed for studying the plasmon enhancement of light absorption from vertically aligned GaAs nanowire arrays decorated with Au nanoparticles. Vertically aligned GaAs nanowires with a length of 1 µm, a diameter of 100 nm and a periodicity of 165-500 nm are functionalized with Au nanoparticles with a diameter between 30 and 60 nm decorated in the sidewall of the nanowires. The results show that the metal nanoparticles can improve the absorption efficiency through their plasmonic resonances, most significantly within the near-bandgap edge of GaAs. By optimizing the nanoparticle parameters, an absorption enhancement of almost 35% at 800 nm wavelength is achieved. The latter increases the chance of generating more electron-hole pairs, which leads to an increase in the overall efficiency of the solar cell. The proposed structure emerges as a promising material combination for high-efficiency solar cells.

Anisotropic deformation of NiO nanoparticles embedded in silica under swift heavy ion irradiation.

We report on the ion-induced anisotropic deformation in nickel oxide nanoparticles prepared by conventional sol-gel technique. Colloidal-like NiO nanoparticles with an average diameter of about 40-50 nm embedded in a SiO2 layer change their shape dramatically under swift heavy ion irradiation with 32 MeV Cu+5 ions at room temperature and normal incidence. Transmission electron microscopy analysis show irradiation induced shape transformation from nearly spherical nanoparticles into oblate nanorods at a rate that increases with ion fluence. For low nanoparticle density, the apparent nanoparticle size aspect ratio increases gradually with increasing irradiation fluence to 5 × 1014 ions cm-2 while no significant volume change is observed upon irradiation. For higher density of the nanoparticles, Rutherford backscattering spectrometry analysis indicates collective growth of nanoparticles under irradiation with fluence above 5 × 1014 ions cm-2. Magnetization experiments of the NiO nanoparticles show that the film consisting the pristine NiO nanoaprticles has a small magnetic anisotropy with axis in the direction parallel to ion beam. However, after 32 MeV Cu+5 ion irradiation, the change in magnetic anisotropy is much larger, which can be correlated with the elongation of nanoparticles in the beam direction. Furthermore, a threshold fluence, under which no deformation takes place is observed.

Inhibitory effect of glutamic acid on the scale formation process using electrochemical methods.

The formation of calcium carbonate CaCO3 in water has some important implications in geoscience researches, ocean chemistry studies, CO2 emission issues and biology. In industry, the scaling phenomenon may cause technical problems, such as reduction in heat transfer efficiency in cooling systems and obstruction of pipes. This paper focuses on the study of the glutamic acid (GA) for reducing CaCO3 scale formation on metallic surfaces in the water of Bir Aissa region. The anti-scaling properties of glutamic acid (GA), used as a complexing agent of Ca(2+) ions, have been evaluated by the chronoamperometry and electrochemical impedance spectroscopy methods in conjunction with a microscopic examination. Chemical and electrochemical study of this water shows a high calcium concentration. The characterization using X-ray diffraction reveals that while the CaCO3 scale formed chemically is a mixture of calcite, aragonite and vaterite, the one deposited electrochemically is a pure calcite. The effect of temperature on the efficiency of the inhibitor was investigated. At 30 and 40°C, a complete scaling inhibition was obtained at a GA concentration of 18 mg/L with 90.2% efficiency rate. However, the efficiency of GA decreased at 50 and 60°C.

Relationship between postoperative infectious complications and glycemic control for diabetic patients in an orthopedic hospital in Kuwait.

OBJECTIVE: To study the relationship between postoperative infectious complications and glycemic control for diabetic patients in an orthopedic hospital in Kuwait. SUBJECTS AND METHODS: Patients who underwent surgical orthopedic procedures between 2006 and 2007 were identified to provide demographic and clinical informations including age, gender, type of surgery, length of operation, HbA(1c) values, nature of specimens and species of the isolated pathogens. HbA(1c) <7% was used as the breaking point for diabetic control and occurrence of postoperative complications. Primary outcomes with infectious complications, including urinary tract infection, surgical site infection (SSI), lower respiratory tract infection and sepsis with different isolated pathogens were identified at least 48 h postoperatively. RESULTS: Of 318 diabetic patients who underwent surgical operations, 90 (28.3%) developed postoperative complications; HbA(1c) <7% was significantly associated with decreased infectious complications with an adjusted odds ratio of 2.51 (95% confidence interval, 1.20-2.89). Regarding types of complications, urinary tract infectious complications were significantly higher among those patients with HbA(1c) > or =7% (p < 0.0001), while other complications (SSI, lower respiratory tract infection and sepsis) showed nonsignificant differences (p > 0.05). CONCLUSIONS: Our study confirmed a close association between preoperative glucose control indicated by HbA(1c) levels <7% and a decreased risk of postoperative infectious complications. Ideally, preoperative blood sugar should be controlled prior to elective surgery. Prophylaxis by antibiotics with preoperative patient preparation, proficient surgical technique and postoperative wound care is recommended for uncontrolled diabetics subjected to surgery.

Multiple myeloma of the central nervous system: a clinicopathological review.

Multiple myeloma (MM) is a systemic malignancy of pathologic plasma cells that is treatable with chemotherapeutic agents and irradiation, but rarely curable. The spectrum of neurological complications of MM is diverse; however, involvement of MM in the cerebrospinal fluid and leptomeningeal infiltration is considered rare. There have been many reviews of central nervous system complications in MM but there are none on intracranial and leptomeningeal infiltration of MM. We review this here along with our clinicopathological experience and a summary of our present knowledge of this condition.

Multiple myeloma of the central nervous system: a clinicopathological review

Multiple myeloma [MM] is a systemic malignancy of pathologic plasma cells that is treatable with chemotherapeutic agents and irradiation, but rarely curable. The spectrum of neurological complications of MM is diverse; however, involvement of MM in the cerebrospinal fluid and leptomeningeal infiltration is considered rare. There have been many reviews of central nervous system complications in MM but there are none on intracranial and leptomeningeal infiltration of MM. We review this here along with our clinicopathological experience and a summary of our present knowledge of this condition