The evolution of cluster network structure and firm growth: a study of industrial software clusters

Since the cluster began to receive attention as a critical environmental factor in geographical economics, it has provided a major research methodology across multiple disciplines from industrial organization, strategic management, regional innovation system, and Triple Helix to virtual clusters. Network structure analysis (NSA) offers a common framework to observe clusters that have been studied separately from the viewpoint of industrial organization and strategic management. Industrial structure analysis, is based on the externality of a network and the resource-based view, focused on the inherent network capacity, have been combined with the study of structural changes through cluster NSA, to create a new direction for the growth of industry and individual firms. This study aims to analyze the correlation between the networking of structural change and a firm’s performance by selecting a software industrial cluster as a representative case for the knowledge industry. We examine the network structural positions of each node during the cluster evolution process. This empirical study has significance for establishing a firm’s growth strategy as well as supporting the policy about clusters, through outlining the dynamic evolution process of the networking activities in a knowledge industry cluster.     

Nanotubular surface and morphology of Ti-binary and Ti-ternary alloys for biocompatibility

The nanotubular surface of Ti-binary and Ti-ternary alloys for biomaterials has been investigated using various methods of surface characterization. Binary Ti-xNb (x = 10, 20, 30, and 40 wt.%) and ternary Ti-30Ta-xNb (x = 3, 7 and 15 wt.%) alloys were prepared by using the high-purity sponges; Ti, Ta and Zr spheres. The nanotube on the alloy surface was formed in 1.0 M H₃PO₄ with small additions of NaF (0.5 and 0.8 wt.%), using a potentiostat. For cell proliferation, an MC3T3-E1 mouse osteoblast was used. The surface characteristics were investigated using field-emission scanning electron microscope, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy.Binary Ti-xZr alloys had a lamellar and a needle-like structure, whereas, ternary Ti-30Ta-xZr alloys had equiaxed grains with a lamellar martensitic α′ structure. The thickness of the needle-like laths of the α-phase increased as the Zr content increased. The nanotubes formed on the α phase and β phase showed a different size and shape appearance with Zr content. As the Zr content increased from 3 to 40 wt.%, the diameter of the nanotubes in Ti-xZr and Ti-30Ta-xZr alloy decreased from 200 nm to 50 nm. The nanotubular Ti-30Ta-15Zr alloy surface with a diameter of 50 nm provided a good osseointegration; cell proliferation, migration and differentiation.     

Oxidative and color stability of cooked ground pork containing lotus leaf (Nelumbo nucifera) and barley leaf (Hordeum vulgare) powder during refrigerated storage

This study aimed to evaluate the oxidative and color stability of cooked ground pork containing lotus leaf powder at 0.1 (LP1) and 0.5% (LP2) as well as barley leaf powder at 0.1 (BP1) and 0.5% (BP2) during refrigerated storage for 10 days. The oxidative stability of these powders was compared with butylhydroxytoluene (BHT). LP1 had higher a* and lower b* values than the control (-) over 4 days (p<0.05). The pH values of the ground pork samples made with addition of LP and BHT decreased until day 4 and then increased. Thiobarbituric acid-reactive substance (TBARS) values were lowest in LP2 on day 10 (p<0.05). The ground pork samples containing LP and BP had lower peroxide values (POVs) and conjugated dienes (CD) compared to the control (-).These results indicate that LP or BP can be incorporated into ground pork to effectively retard oxidation after cooking.     

Synthesis of copper nanoparticles by solid-state plasma-induced dewetting

Copper nanoparticles were prepared by the plasma treatment of Cu thin films without extra heating. The Cu nanoparticles were formed through a solid-state dewetting process at temperatures of less than 450 K. The particle sizes, from 10 to 80 nm, were controlled by changing the thickness of the Cu film; the particle size increased linearly with the film thickness. The Cu nanoparticles produced by plasma treatment showed an excellent size uniformity compared to those prepared by heat treatment. In the early stage of the dewetting of the Cu film, uniformly distributed holes nucleated, and the holes grew and coalesced until the Cu nanoparticles were formed. The low operating temperatures used contributed to the production of uniform Cu nanoparticles.     

Control of domain wall pinning in ferromagnetic nanowires by magnetic stray fields

We have found that the depinning field of domain walls (DWs) in permalloy (Ni(81)Fe(19)) nanowires can be experimentally controlled by interactions between magnetic stray fields and artificial constrictions. A pinning geometry that consists of a notch and a nanobar is considered, where a DW traveling in the nanowire is pinned by the notch with a nanobar vertical to it. We have found that the direction of magnetization of the nanobar affects the shape and local energy minimum of the potential landscape experienced by the DW; therefore, the pinning strength strongly depends on the interaction of the magnetic stray field from the nanobar with the external pinning force of the notch. The mechanism of this pinning behavior is applied for the instant and flexible control of the pinning strength with respect to various DW motions in DW-mediated magnetic memory devices.     

Surface characteristics of hydroxyapatite/titanium composite layer on the Ti-35Ta-xZr surface by RF and DC sputtering

The purpose of this study was to investigate the surface characteristics of hydroxyapatite (HA)/titanium (Ti) composite layer on the Ti-35Ta-xZr alloy surface by radio frequency (RF) and direct current (DC) sputtering for dental application. The magnetron sputtered deposition for the HA was performed in the RF mode and for the Ti in the DC mode. Microstructures of the alloys were examined by optical microscopy (OM) and x-ray diffractometer (XRD). Surface characteristics of coated film was investigated by field-emission scanning electron microscope (FE-SEM) equipped with an energy dispersive x-ray spectrometer (EDS), and XRD. Microstructures of the Ti-35Ta-xZr alloys were changed from α″ phase to β phase, and changed from a needle-like structure to an equiaxed structure with increasing Zr content. From the results of polarization behavior in the Ti-35Ta-15Zr alloy, HA/Ti composite layer showed the good corrosion resistance compared to Ti single layer. The results of alternating current (AC) impedance test indicated that the presence of ha coating acted as a stable barrier in increasing the corrosion resistance.     

Neuronal laterality in Parkinson''s disease with unilateral symptom by in vivo 1H magnetic resonance spectroscopy

PURPOSE: The aim of the present study was to investigate carcinoembryonic antigen (CEA), CA19.9, and CA72.4 in the serum and gastric juice of patients with gastric cancer. METHODS: Serum and gastric juice tumor markers CEA, CA19.9, and CA72.4 were measured in 59 patients who had gastric adenocarcinomas and were undergoing curative gastrectomy. The same markers were measured in 47 patients with benign gastric disorders and in 40 healthy subjects. The correlation between the serum and gastric juice levels of tumor markers and several clinicopathological factors were evaluated by univariate analysis. The significance of the tumor markers as prognostic factors was assessed both by univariate and multivariate analysis. RESULTS: The positivity rates of serum CEA, CA19.9, and CA72.4 were 57.6%, 38.9%, and 18.6% respectively. The positivity rates of gastric juice CEA, CA19.9, and CA72.4 were 62.7%, 30.5%, and 23.7% respectively. The combination of serum and gastric juice markers gave a positivity of 81.3%. There was no correlation between serum and gastric juice level of each tumor marker. Positivity of gastric juice markers did not correlate with prognosis. A significant difference in prognosis was observed between patients positive and negative for serum CEA and CA19.9. Multivariate analysis also revealed that serum CEA and CA19.9 levels were independent prognostic factors. CONCLUSIONS: Levels of both serum and gastric juice tumor markers continue to have only limited diagnostic usefulness in gastric cancer patients. CEA and CA19.9 in the preoperative sera are good prognostic factors, whereas the presence of tumor markers in the gastric juice does not play any prognostic role.