A contingent model of network utilization in early financing of technology ventures

Most of the entrepreneurship literature has addressed the benefits and necessity of using social network ties as opposed to market methods in early venture finance, but it has largely understated the potential limitations and costs of doing so. Specifically, very sparse research has examined the factors that influence entrepreneurs' choice between using networks versus market methods. In this study, we propose a contingent model of network utilization when approaching initial investors, based on the dimensions of human capital of the entrepreneurs. We test this model with primary field survey data from 226 new high-tech ventures in Singapore and Beijing. The results show that high occupational status and relevant industrial work experience are positively associated with the entrepreneurs' propensity to utilize existing networks by enhancing the resourcefulness of their network ties (social capital); however, such influences are alleviated by entrepreneurs' marketing or managerial experience, which increases the entrepreneurs' ability to interact with strangers (an aspect of social competence)

Synthesis, Characterization and Catalytic Activity of Cu/Cu2O Nanoparticles Prepared in Aqueous Medium

Copper/Copper oxide (Cu/Cu2O) nanoparticles were synthesized by modified chemical reduction method in an aqueous medium using hydrazine as reducing agent and copper sulfate pentahydrate as precursor. The Cu/Cu2O nanoparticles were characterized by X-ray Diffraction (XRD), Energy Dispersive X-ray Fluorescence (EDXRF), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). The analysis revealed the pattern of face-centered cubic (fcc) crystal structure of copper Cu metal and cubic cuprites structure for Cu2O. The SEM result showed monodispersed and agglomerated particles with two micron sizes of about 180 nm and 800 nm, respectively. The TEM result showed few single crystal particles of face-centered cubic structures with average particle size about 11-14 nm. The catalytic activity of Cu/Cu2O nanoparticles for the decomposition of hydrogen peroxide was investigated and compared with manganese oxide MnO2. The results showed that the second-order equation provides the best correlation for the catalytic decomposition of H2O2 on Cu/Cu2O. The catalytic activity of hydrogen peroxide by Cu/Cu2O is less than the catalytic activity of MnO2 due to the presence of copper metal Cu with cuprous oxide Cu2O. © 2015 BCREC UNDIP. All rights reservedReceived: 6th January 2015; Revised: 14th March 2015; Accepted: 15th March 2015How to Cite: Badawy, S.M., El-Khashab, R.A., Nayl, A.A. (2015). Synthesis, Characterization and Catalytic Activity of Cu/Cu2O Nanoparticles Prepared in Aqueous Medium. Bulletin of Chemical Reaction Engineering &amp; Catalysis, 10 (2): 169-174. (doi:10.9767/bcrec.10.2.7984.169-174) Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.7984.169-174  </p

Differential expression analysis in Egyptian redbelly tilapia (Tilapia Zillii) exposed to cold stress

Fish can adapt to a wide range of temperature changes, however, the molecular mechanisms that underlie these adaptations are not fully understood. In this study, fluorescently labeled differential display (FDD) technique was used to detect mRNAs that are differentially expressed in hepatic tissues of Tilapia zillii fish subjected to a temperature reduction regime that combined both accelerated and stationary cold stresses. The two arbitrary primers (DD1 and DD2) with the Oligo d(T)23-C generated a total of 18 and 37 unknown messenger RNA (UMR) bands, respectively. Both DD1 & DD2 arbitrary primers with oligo d(T)23-C scored four stress-related unidentified fragments after refining. Using the two arbitrary primers with the Oligo d(T)23-G, a total of 371 and 372 UmRs were yielded, respectively. Both arbitrary primers scored nine stress-related unidentified fragments after refining. All UmR were tested for its correlation to time and temperature factors scaled for the current experiment, only four were found to be correlated for both factors. Thus, T. zillii responded to temperature reduction by adjusting the expression of a set number of genes that may be required for their adaptation and tolerance to low environmental temperature

Changes of paired-pulse evoked responses during the development of epileptic activity in the hippocampus*

Dysfunction of inhibitory synaptic transmission can destroy the balance between excitatory and inhibitory synaptic inputs in neurons, thereby inducing epileptic activity. The aim of the paper is to investigate the effects of successive excitatory inputs on the epileptic activity induced in the absence of inhibitions. Paired-pulse orthodromic and antidromic stimulations were used to test the changes in the evoked responses in the hippocampus. Picrotoxin (PTX), γ-aminobutyric acid (GABA) type A (GABAA) receptor antagonist, was added to block the inhibitory synaptic transmission and to establish the epileptic model. Extracellular evoked population spike (PS) was recorded in the CA1 region of the hippocampus. The results showed that the application of PTX induced a biphasic change in the paired-pulse ratio of PS amplitude. A short latency increase of the second PS (PS2) was later followed by a reappearance of PS2 depression. This type of depression was observed in both orthodromic and antidromic paired-pulse responses, whereas the GABAergic PS2 depression [called paired-pulse depression (PPD)] during baseline recordings only appeared in orthodromic-evoked responses. In addition, the depression duration at approximately 100 ms was consistent with a relative silent period observed within spontaneous burst discharges induced by prolonged application of PTX. In conclusion, the neurons may ignore the excitatory inputs and intrinsically generate bursts during epileptic activity. The depolarization block could be the mechanisms underlying the PPD in the absence of GABAA inhibitions. The distinct neuronal responses to stimulations during different epileptic stages may implicate the different antiepileptic effects of electrical stimulation