Electron beam lithography on nonplanar and irregular surfaces.

E-beam lithography is a powerful tool for generating nanostructures and fabricating nanodevices with fine features approaching a few nanometers in size. However, alternative approaches to conventional spin coating and development processes are required to optimize the lithography procedure on irregular surfaces. In this review, we summarize the state of the art in nanofabrication on irregular substrates using e-beam lithography. To overcome these challenges, unconventional methods have been developed. For instance, polymeric and nonpolymeric materials can be sprayed or evaporated to form uniform layers of electron-sensitive materials on irregular substrates. Moreover, chemical bonds can be applied to help form polymer brushes or self-assembled monolayers on these surfaces. In addition, thermal oxides can serve as resists, as the etching rate in solution changes after e-beam exposure. Furthermore, e-beam lithography tools can be combined with cryostages, evaporation systems, and metal deposition chambers for sample development and lift-off while maintaining low temperatures. Metallic nanopyramids can be fabricated on an AFM tip by utilizing ice as a positive resistor. Additionally, Ti/Au caps can be patterned around a carbon nanotube. Moreover, 3D nanostructures can be formed on irregular surfaces by exposing layers of anisole on organic ice surfaces with a focused e-beam. These advances in e-beam lithography on irregular substrates, including uniform film coating, instrumentation improvement, and new pattern transferring method development, substantially extend its capabilities in the fabrication and application of nanoscale structures.

Experimental realization of neutron helical waves.

Methods of preparation and analysis of structured waves of light, electrons, and atoms have been advancing rapidly. Despite the proven power of neutrons for material characterization and studies of fundamental physics, neutron science has not been able to fully integrate these techniques because of small transverse coherence lengths, the relatively poor resolution of spatial detectors, and low fluence rates. Here, we demonstrate methods that are practical with the existing technologies and show the experimental achievement of neutron helical wavefronts that carry well-defined orbital angular momentum values. We discuss possible applications and extensions to spin-orbit correlations and material characterization techniques.

Trace metal fractions, sources, and risk assessment in sediments from Umurbey Stream (Çanakkale-Turkey).

Trace metal contamination has become a worldwide problem for aquatic systems, as sediments act as a sink for trace metals. This study was conducted to assess geochemical fractions, sources and potential risks of trace metals (Cd, Cr, Cu, Ni, Pb, and Zn) in sediments of Umurbey stream (Çanakkale-Turkey). Sediment samples were taken from seven different locations of Umurbey stream. Aqua regia wet digestion procedure was applied to determine total contents of trace metals and BCR sequential extraction procedure was applied to determine geochemical fractions of trace metals. Trace metal total values were ordered as Zn > Pb > Cr > Cu > Ni > Cd. Just because of topography, geology, and agricultural practices, S4, S5, S6, and S7 sampling points had greater total trace metal concentrations than the other locations. Potential mobility of trace metals in sediment samples was ordered as Cd (62.1%) > Zn (60.8%) > Pb (54.8%) > Cu (46.1%) > Cr (43.0%) > Ni (29.7%). Cd, Zn, Pb, and partially Cu were encountered mostly in mobile phases. Multivariate analyses revealed that pollution in sediment samples was originated from not only anthropogenic but also natural factors. Except for Zn, trace metal concentrations were found to be at tolerable levels of biota. When the contamination factor and risk assessment code results were assessed together, it was observed that Cd, Zn, and partially Pb were weakly adsorbed onto sediments, thus might pose risks on environment in the long run.

Efficacy of preoperative albendazole use according to months in hydatid cyst of the liver.

PURPOSE: Hydatid cyst is still a significant health and economical problem due to insufficient preventive measures. Infestation by hydatid disease in humans most commonly occurs in the liver and causes complications unless treated properly. Therefore, hepatic hydatid cyst should immediately be treated when diagnosed. Today, the treatment of hydatid cysts is principally surgical. To avoid recurrence, viable scoleces in the hydatid cyst should be eliminated before emptying surgically. Length of Albendazole therapy, a drug effective on scoleces in the cyst, is still controversial. METHODS: In this study, there was a significant difference in the rate of viable scoleces when group III receiving albendazole for 3 months preoperatively was compared with group I, group II, and the control group. We do think 3-month preoperative abendazole treatment is effective in reducing the rate of recurrence and if still viable scoleces are observed in the surgery, albendazole treatment should be continued for 1 month postoperatively. RESULTS: After the therapy, in group I 10 (47.6%), in group II 7 (33.3%), and in group III 2 (0.9%) patient's scoleces were alive. In the control group (group IV) 17 (80%) patients' scoleces were intact. When group III is compared with the control group, a significant difference was observed (P<0.05). Yet again, there was a significant difference between the groups when groups I and II were compared with group III. CONCLUSIONS: We concluded that in treatment of hydatid cyst, albendazole should be continued at least for 3 months preoperatively and if still viable scoleces are identified, medical treatment should follow the surgical intervention at least for 1 month to decrease the possibility of residual cysts and recurrence.

Assessment of the water quality of Troia for the multipurpose usages.

The aim of this study was to determine the origin and quality of waters in Troia. For this purpose total of 25 water samples including 2 springs, 14 surfaces and 9 groundwaters, were collected at eight different times. Global positioning system (GPS) was used to determine to coordinates of sampling points. The concentration of 6 minor elements (B, Cu, F, Fe, Pb and Zn), 9 major anions and cations (Na(+), Ca(2+), K(+), Mg(2+), SO(4)(2-), PO(4)(3-), HCO(3)(-), Cl(-) and, CO(3)(2-)) were determined by spectrometric, colorimetric and volumetric methods. Water pH, EC, DO, ORP and TDS were measured in situ using probes. The data showed that the concentrations of most of minor elements were below the EPA and TSE limits except Pb which ranged between 0.001 and 4.832 mg L(-1). Statistically significant relationships (P<0.01 and r>0.70) were observed between Fe and Cu, Cu and K(+), Cu and Ca(2+), B and Na(+), Na(+) and K(+). Assessing the water based on irrigation using Wilcox model showed that some well waters were not suitable for irrigation. Troia water was found to be highly corrosive and the average corrosion coefficients varied from 0.5 to 4.6. According to the Piper and Schoeller diagrams results, the water in Troia was classified as mixed water type.

Omeprazole is more effective than famotidine for preventing acute gastritis in rats.

PURPOSE: Acute gastric mucosal lesions, which can develop within a few hours after polytrauma, shock, major operations, central nervous system lesions, or severe infection, cause about 33% of cases of gastrointestinal bleeding. We analyzed and compared the effectiveness of famotidine and omeprazole on acute gastric mucosal lesions. METHODS: Thirty male albino Wistar rats were given ketalar anesthesia after 12 h fasting, then immobilized and exposed to stress according to Brodie's protocol, without restricting their respiration. We divided the rats into three groups of ten according to whether they were given famotidine, omeprazole, or normal saline (control group). All rats were ulcer-indexed according to the diameter of their ulcers. The stomach contents were aspirated for acid output and pH analysis, and sent to the laboratory. The total number of mast cells was also counted. RESULTS: Omeprazole was more effective than famotidine in keeping gastric pH high and lowering the total gastric acid output. Lower ulcer indexes in acute gastric mucosal erosions and better protected mucosal integrity were found in the omeprazole-treated rats. CONCLUSION: Omeprazole prevents acute gastric mucosal erosions in rats more effectively than famotidine.