Apoptosis induced by copper oxide quantum dots in cultured C2C12 cells via caspase 3 and caspase 7: a study on cytotoxicity assessment.

We report herein the synthesis and characterization of copper oxide quantum dots and their cytotoxic impact on mouse C2C12 cells. The utilized CuO quantum dots were prepared by the one-pot wet chemical method using copper acetate and hexamethylenetetramine as precursors. The physicochemical characterization of the synthesized CuO quantum dots was carried out using X-ray diffraction, energy-dispersive X-ray analysis, and transmission electron microscopy. To examine the in vitro cytotoxicity, C2C12 cell lines were treated with different concentrations of as-prepared quantum dots and the viability of cells was analyzed using Cell Counting Kit-8 assay at regular time intervals. The morphology of the treated C2C12 cells was observed under a phase-contrast microscope, whereas the quantification of cell viability was carried out via confocal laser scanning microscopy. To gain insight into the mechanism of cell death, we examined the effect of CuO quantum dots on the candidate genes such as caspases 3 and 7, which are key mediators of apoptotic events. In vitro investigations of the biological effect of CuO quantum dots have shown that it binds genomic DNA, decreases significantly the viability of cells in culture in a concentration (10-20 µg/mL) dependent manner, and inhibits mitochondrial caspases 3 and 7. To sum up, the elucidation of the pathways is to help in understanding CuO quantum dot-induced effects and evaluating CuO quantum dot-related hazards to human health.

Immobilization of angiotensin II and bovine serum albumin on strip-patterned ZnO nanorod arrays.

For an effective protein immobilization for highly sensitive biosensors, we determined the binding properties and characteristics of angiotensin II and bovine serum albumin on the surface of patterned ZnO nanorod arrays (NRAs) which were selectively grown on desired areas of Si substrates. The surfaces of ZnO NRAs were modified by 3-aminopropyltriethoxysilane and gluteraldehyde, and the activated NRAs were then conjugated with angiotensin II protein and bovine serum albumin. The silanization process and conjugation of protein were verified by secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS) techniques. The immobilizing densities of proteins determined by Coomassie protein assay were 4.5 microg/cm2 for angiotensin II and 5.3 microg/cm2 for bovine serum albumin.

High aspect-ratio ZnO nanowires based nanoscale field effect transistors.

High aspect-ratio ZnO nanowires were grown onto the copper foil, in a large-quantity, by non-catalytic thermal evaporation method. The detailed morphological observations revealed that the diameters and lengths of as-grown nanowires are in the range of 60-100 nm and 10-30 microm, respectively exhibiting a very high-aspect ratio. Detailed structural characterizations confirmed that the as-grown nanowires are well crystalline and possess a wurtzite hexagonal phase, grown along the c-axis direction in preference. The presence of a sharp and strong UV emission at 381 nm in the room temperature photoluminescence (PL) spectrum affirmed that the obtained nanowires have good optical properties. The electrical transport properties of the as-grown nanowires was explored by fabricating the field effect transistors (FETs) using a single ZnO nanowire. From the fabricated single ZnO nanowire based FET, the electron carrier density and field effect mobility were estimated to be approximately 6.7 x 10(13) cm(-3) and approximately 3.8 cm2/Vs, respectively.

Highly-sensitive cholesterol biosensor based on well-crystallized flower-shaped ZnO nanostructures.

This paper reports the fabrication of highly-sensitive cholesterol biosensor based on cholesterol oxidase (ChOx) immobilization on well-crystallized flower-shaped ZnO structures composed of perfectly hexagonal-shaped ZnO nanorods grown by low-temperature simple solution process. The fabricated cholesterol biosensors reported a very high and reproducible sensitivity of 61.7 microA microM(-1)cm(-2) with a response time less than 5s and detection limit (based on S/N ratio) of 0.012 microM. The biosensor exhibited a linear dynamic range from 1.0-15.0 microM and correlation coefficient of R=0.9979. A lower value of apparent Michaelis-Menten constant (K(m)(app)), of 2.57 mM, exhibited a high affinity between the cholesterol and ChOx immobilized on flower-shaped ZnO structures. Moreover, the effect of pH on ChOx activity on the ZnO modified electrode has also been studied in the range of 5.0-9.0 which exhibited a best enzymatic activity at the pH range of 6.8-7.6. To the best of our knowledge, this is the first report in which such a very high-sensitivity and low detection limit has been achieved for the cholesterol biosensor by using ZnO nanostructures modified electrodes.

ZnO nanonails: synthesis and their application as glucose biosensor.

Well-crystallized zinc oxide nanonails were grown in a high density by thermal evaporation process and were used as supporting matrixes for glucose oxidase (GOx) immobilization to construct efficient glucose biosensor. The GOx attached to the surfaces of ZnO nanonails had more spatial freedom in its orientation, which facilitated the direct electron transfer between the active sites of immobilized GOx and electrode surface. The fabricated biosensor showed a high sensitivity of 24.613 microA cm(-2) mM(-1) with a response time less than 10 s. Moreover, it shows a linear range from 0.1 to 7.1 mM with a correlation coefficient of R = 0.9937 and detection limit of 5 microM.

Growth mechanism and optical properties of aligned hexagonal ZnO nanoprisms synthesized by noncatalytic thermal evaporation.

Vertically aligned perfectly hexagonal-shaped ZnO nanoprisms have been grown on a Si(100) substrate via a noncatalytic thermal evaporation process by using metallic zinc powder in the presence of oxygen gas. The as-grown nanoprisms consist of ultra smooth Zn-terminated (0001) facets bounded with the {0110} surfaces. The as-synthesized products are single-crystalline with the wurtzite hexagonal phase and grown along the [0001] direction, as confirmed from the detailed structural investigations. The presence of a sharp and strong nonpolar optical phonon high-E2 mode at 437 cm(-1) in the Raman scattering spectrum further confirms good crystallinity and wurtzite hexagonal phase for the as-grown products. The as-grown nanoprisms exhibit a strong near-band-edge emission with a very weak deep-level emission in the room-temperature and low-temperature photoluminescence measurements, confirming good optical properties for the deposited products. Moreover, systematic time-dependent experiments were also performed to determine the growth process of the grown vertically aligned nanoprisms.

Hierarchical ZnO nanostructures: growth and optical properties.

Growth of hierarchical ZnO nanostructures composed of ZnO nanoneedles have been achieved via simple thermal evaporation process by using metallic zinc powder in the presence of oxygen at low temperature of 460 degrees C on silicon substrate without the use of any kind of metal catalysts or additives. It is confirmed by detailed structural studies that the as-grown hierarchical nanostructures are single crystalline with a wurtzite hexagonal phase and nanoneedles of these structures are grown along the c-axis in the [0001] direction. The Raman-scattering analysis substantiates a wurtzite hexagonal phase with a good crystal quality for the as-grown products. Room-temperature photoluminescence (PL) exhibits a strong UV emission at 380 nm confirming the excellent optical properties of as-synthesized hierarchical structures. A plausible growth mechanism is also proposed to clearly understand the growth process of the synthesized structures.

Comparison between the electrical properties of ZnO nanowires based field effect transistors fabricated by back- and top-gate approaches.

Large-quality, well-crystallized growth of ZnO nanowires was done via non-catalytic thermal evaporation process on silicon substrate only by using metallic zinc powder and oxygen as source materials for zinc and oxygen, respectively. The electrical properties of the as-grown ZnO nanowires were examined by fabricating a single nanowire based FETs which were fabricated via two approaches, i.e., back- and top-gate approaches by using electron beam lithography (EBL) and photolithography processes. ZnO FETs electrical properties were characterized by I(DS)-V(DS) and I(DS)-V(GS) measurement. The fabricated single ZnO nanowire based FETs by back- and top-gate approaches exhibited field effect mobilities of approximately 4.25 and approximately 12.76 cm2/Vs, respectively. Moreover, the carrier concentrations for the fabricated back- and top-gate FETs were approximately 1.6 x 10(17) and approximately 1.37 x 10(18) cm(-3), respectively. From our studies it was observed that the fabricated top-gate FETs exhibited higher and good electrical properties as compared to ZnO nanowire FETs fabricated using back-gate approaches.

Luminescence from single CdSe nanocrystals embedded in ZnO thin films using atomic layer deposition.

We report the embedding of CdSe/ZnS core-shell nanocrystals into thin films of ZnO grown by atomic layer deposition. Fluorescence from ensembles and that from individual nanocrystals show that the nanocrystal luminescence intensity and stability are preserved through the embedding process. These results are encouraging for the fabrication of optoelectronic nanodevices based on colloidal nanoparticles.

Low-temperature growth of flower-shaped UV-emitting ZnO nanostructures on steel alloy by thermal evaporation.

Flower-shaped ZnO nanostructures, containing the triangular-shaped petals (sharpened tips and wider bases) have been achieved by simple thermal evaporation of high purity metallic zinc powder in the presence of oxygen at 440 degrees C on steel alloy substrate without the use of metal catalyst or additives. Detailed structural studies confirm that the obtained flower-shaped nanostructures are single crystalline and possesses a wurtzite hexagonal structure, grown along the c-axis in the [0001] direction. Raman and room temperature photoluminescence analysis substantiate a wurtzite hexagonal phase with a good crystal quality and a strong UV emission at 378 nm, respectively, indicating few or no structural defects. Additionally, a detailed possible growth mechanism has also been discussed.

Two-step growth of hexagonal-shaped ZnO nanowires and nanorods and their properties.

Single-crystalline with perfect hexagonal-shaped ZnO nanowires and nanorods, possessing the Zn-terminated (0001) facets bounded with the six-crystallographic equivalent [0110] surfaces, have been grown on Au-coated silicon substrate via thermal evaporation method using the metallic zinc powder in presence of oxygen. The detailed structural analyses reveal that the obtained nanostructures are single-crystalline with the wurtzite hexagonal phase and are preferentially oriented in the c-axis, [0001] direction. Raman spectra exhibit a sharp and strong optical phonon E2 mode at 437 cm(-1) further confirms the good crystal quality with wurtzite hexagonal crystal structure for the deposited products. The room-temperature photoluminescence (PL) spectra, for both the structures, showed a sharp and strong UV emission with a suppressed green emission, indicating the good optical properties for the as-grown nanostructures.

Structural and optical properties of single-crystalline ZnO nanorods grown on silicon by thermal evaporation.

The growth of perfectly hexagonal-shaped ZnO nanorods, with Zn-terminated (0001) facets bounded with [Formula: see text] surfaces, has been performed on nickel-coated Si(100) substrate via thermal evaporation using metallic zinc powder and oxygen. Detailed structural investigations confirmed that the synthesized nanorods are single crystalline with the wurtzite hexagonal phase and preferentially grow along the c-axis direction. Raman spectra of the as-grown ZnO nanorods showed an optical-phonon E(2) mode at 438 cm(-1), indicating that as-grown nanostructures are in good crystallinity with the wurtzite hexagonal phase. The ZnO nanorods were found to show strong band edge emission with very weak or no deep-level emission, as shown by photoluminescence measurements. The clear observation of free excitons at low temperatures (13-50 K) indicates that the as-grown ZnO nanorods are of high quality.

Flower-shaped ZnO nanostructures obtained by cyclic feeding chemical vapour deposition: structural and optical properties.

Flower-shaped ZnO nanostructures were grown on Si(100) and Si(111) substrates by cyclic feeding chemical vapour deposition without the use of a metal catalyst. The structures obtained on the Si(100) substrate exhibited triangle-shaped leaves with lengths and diameters in the ranges 300-400 and 90-130 nm, respectively. Uniformly shaped leaves with hexagonal facets originating from one centre were observed on the flower-shaped structures grown on the Si(111) substrate. Transmission electron microscopy and selected area electron diffraction patterns showed that these structures are highly crystalline, with the wurtzite hexagonal phase, and preferentially oriented in the c-axis direction. Unlike star-shaped ZnO nanostructures grown on Au-coated silicon substrates, the flower-shaped nanostructures showed sharp and strong UV emission at 378 nm and broad and weak green emission at 520 nm, indicating a good crystal quality and few structural defects.

The effect of thermal biofeedback and progressive muscle relaxation training in reducing blood pressure of patients with essential hypertension.

In order to assess the effectiveness of the thermal biofeedback training combined with the progressive muscle relaxation therapy in the treatment of patients with essential hypertension, blood pressure decline was measured on the treatment group who had the combined thermal biofeedback and progressive muscle relaxation training (N = 11), and on the control group who had only the progressive muscle relaxation training (N = 8). Baseline blood pressure was measured four times for two weeks on both groups. For the treatment group, blood pressure was measured twice before and after each of eight sessions of thermal biofeedback training for four weeks. For the control group, blood pressure was measured every two visits to a clinic for progressive muscle relaxation self-training twice before and after the self-training. A significant decline of the systolic blood pressure by 20.6 mmHg and of the diastolic blood pressure by 14.4 mmhg was observed in the treatment group. There was a tendency for both blood pressures to increase in the control group.

[Quality of life of middle aged persons who have cancer].

This descriptive study was under taken to explore relationships among the quality of life, health locus of control and perceived state of health persons with cancer to contribute theoretical understanding about these phenomenon of interest to the quality of nursing care. The subjects of this were 200 persons with cancer (100-in patients and 100-out patients), both male and female, between 30 and 59 years of age. Data were obtained using a convenience sample technique from two university hospitals in seoul from August, 1989, to June, 1990. The instruments used for this study were the Quality of life scale developed by Ro, You-Ja and the Health Locus of Control scale developed by Wallston & Wallston. Data were analyzed using a SAS program for ANOVA, t-test, Schefffé test, Pearson Correlation Coefficients and Stepwise multiple regression. The results were as follows: 1. The scores on the quality of life scale ranged from 95 to 191 with as mean of 147.85 (range 47 to 235). The Mean scores (range 1-5) on the different dimensions were family relationships 3.50, relationships with neighbours 3.48, self-esteem 3.17, physical state and function 2.99, economic life 2.93 and emotional life 2.91. 2. Significantly higher scores on the quality of life and demographic characteristics were as follows: the quality of life for women (t = 2.80, p = .006), for those without complications (t = 2.54, p = .013), and for those who perceived their illness as mild (F = 4.85, p = .009). Higher scores on quality of life were correlated with the following: 1) emotional state and the age group 50-59 (F = 3.43, p = .34). 2) economic life and higher income (F = 6.72, p = .002), those without complications (t = 2.68, p = .00), and those who perceived their illness as mild (F = 3.11, p = .05). 3) self-esteem and marriage (F = 3.64, p = .028), those without complications (t = 2.18, p = .03), and those who perceived their illness as mild (F = 7.72, p = .000). 4) physical state and function and the age group 30-39 (F = 4.65, p = .010), those without complications (t = 2.00, p = .05), and those who perceived their illness as mild (F = 3.38, p = .04). 5) family relationship and those who live with their spouse (t = 2.82, p = .005).(ABSTRACT TRUNCATED AT 400 WORDS)