Optimization of CdS Buffer Layer for High Efficiency CIGS Solar Cells.

In present work, effects of the thickness on the structural and optical properties of chemically deposited CdS thin films were investigated. In addition, we fabricated Cu(In, Ga)Se2 solar cells with various thicknesses of CdS buffer layer and optimized the thickness for a high efficiency. When the CdS thin films were thicker, the crystallinity improved but the transmittance decreased. The short-circuit current density (J(sc)) and the fill factor are the major efficiency limiting factors for the CIGS solar cells. As the thickness of the CdS buffer layer, the open-circuit voltage (V(oc)) and the fill factor increased, whereas the J(sc) slightly decreased. The improvement of the fill factor and thus efficiency resulted from larger shunt resistance. For the solar cells without a high resistive intrinsic ZnO layer, the highest efficiency was acquired at the thickness of 89 nm. With further increasing the thickness, the J(sc) decreased significantly, resulting in poor efficiency.

Influence of Oxygen Gas Ratio on the Properties of Aluminum-Doped Zinc Oxide Films Prepared by Radio Frequency Magnetron Sputtering.

Aluminum-doped zinc oxide (AZO) thin films were deposited on glass and polyimide substrates using radio frequency magnetron sputtering. We investigated the effects of the oxygen gas ratio on the properties of the AZO films for Cu(In,Ga)Se2 thin-film solar cell applications. The structural and optical properties of the AZO thin films were measured using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and UV-Visible-NIR spectrophotometry. The oxygen gas ratio played a crucial role in controlling the optical as well as electrical properties of the films. When oxygen gas was added into the film, the surface AZO thin films became smoother and the grains were enlarged while the preferred orientation changed from (0 0 2) to (1 0 0) plane direction of the hexagonal phase. An improvement in the transmittance of the AZO thin films was achieved with the addition of 2.5-% oxygen gas. The electrical resistivity was highly increased even for a small amount of the oxygen gas addition.

Fingertip reconstruction with simultaneous flaps and nail bed grafts following amputation.

PURPOSE: To report our technique and results with treating fingertip amputations with flaps and simultaneous nailbed grafts. METHODS: We reconstructed 20 fingertip amputations with loss of bone and nail with flaps combined with nailbed grafts. We reconstructed the volar side of the fingertip with a flap, and the dorsal side of the fingertip with a nailbed grafted to the raw inner surface of the flap. We employed volar V-Y advancement flaps for transverse or dorsal oblique fingertip injuries and generally used abdominal flaps for volar oblique fingertip injuries. We harvested nailbeds from the amputated finger or from the patient's first toe. RESULTS: The length of the amputated fingertips was restored with the flaps, and the lost nailbeds were restored to their natural appearance with the nailbed grafts. We classified the results according to the length of the reconstructed fingertip and the appearance of the nail. Excellent or good results were achieved in 16 cases. Three cases had fair results and 1 had a poor result. We observed favorable results for distal fingertip amputations (Allen type II or III). In particular, most cases that were reconstructed with volar V-Y advancement flaps combined with nailbed grafts demonstrated favorable results. CONCLUSIONS: This method is useful for the restoration of dorsal oblique or transverse type fingertip amputations and is a good alternative when replantation is not an option.

A simple audio-visual prompt device can improve CPR performance.

BACKGROUND: An adjunct to assist cardiopulmonary resuscitation (CPR) might improve the quality of CPR performance. STUDY OBJECTIVES: This study was conducted to evaluate whether a simple audio-visual prompt device improves CPR performance by emergency medical technicians (EMTs). METHODS: From June 2008 to October 2008, 55 EMTs (39 men, mean age 34.9±4.8 years) participated in this study. A simple audio-visual prompt device was developed. The device generates continuous metronomic sounds for chest compression at a rate of 100 beats/min with a distinct 30(th) sound followed by two respiration sounds, each for 1 second. All EMTs were asked to perform a 2-min CPR series on a manikin without the device, and one 2-min CPR series with the device. RESULTS: The average rate of chest compressions was more accurate when the device was used than when the device was not used (101.4±12.7 vs. 109.0±17.4/min, respectively, p=0.012; 95% confidence interval [CI] 97.2-103.8 vs. 104.5-113.5/min, respectively), and hands-off time during CPR was shorter when the device was used than when the device was not used (5.4±0.9 vs. 9.2±3.9 s, respectively, p<0.001; 95% CI 5.2-5.7 vs. 8.3-10.3 s, respectively). The mean tidal volume during CPR with the device was lower than without the device, resulting in the prevention of hyperventilation (477.6±60.0 vs. 636.6±153.4 mL, respectively, p<0.001; 95% CI 463.5-496.2 vs. 607.3-688.9 mL, respectively). CONCLUSION: A simple audio-visual prompt device can improve CPR performance by emergency medical technicians.

Review of natural products actions on cytokines in inflammatory bowel disease.

The purpose of this review is to provide an overview of the effects that natural products have on inflammatory bowel disease (IBD) and to provide insight into the relationship between these natural products and cytokines modulation. More than 100 studies from the past 10 years were reviewed herein on the therapeutic approaches for treating IBD. The natural products having anti-IBD actions included phytochemicals, antioxidants, microorganisms, dietary fibers, and lipids. The literature revealed that many of these natural products exert anti-IBD activity by altering cytokine production. Specifically, phytochemicals such as polyphenols or flavonoids are the most abundant, naturally occurring anti-IBD substances. The anti-IBD effects of lipids were primarily related to the n-3 polyunsaturated fatty acids. The anti-IBD effects of phytochemicals were associated with modulating the levels of tumor necrosis factor α (TNF-α), interleukin (IL)-1, IL-6, inducible nitric oxide synthase, and myeloperoxide. The anti-IBD effects of dietary fiber were mainly mediated via peroxisome proliferator-activated receptor-γ, TNF-α, nitric oxide, and IL-2, whereas the anti-IBD effects of lactic acid bacteria were reported to influence interferon-γ, IL-6, IL-12, TNF-α, and nuclear factor-κ light-chain enhancer of activated B cells. These results suggest that the anti-IBD effects exhibited by natural products are mainly caused by their ability to modulate cytokine production. However, the exact mechanism of action of natural products for IBD therapy is still unclear. Thus, future research is needed to examine the effect of these natural products on IBD and to determine which factors are most strongly correlated with reducing IBD or controlling the symptoms of IBD.