ACE research vignette 036 : SMEs, Growth, and Job Creation: Lessons from Systematic Research

This series of research vignettes is aimed at sharing current and interesting research findings from our team of international Entrepreneurship researchers. This vignette, written by Professor Per Davidsson, summarises some important, stylized facts about small and medium enterprises (SMEs), growth, and job creation. It was specially prepared for “The G20 Agenda for Growth: Opportunities for SMEs Conference” in Melbourne, June 20, 2014. For this reason its format deviates slightly from other vignettes in the series.

Promoting resilience in children with intellectual disability : a randomized controlled trial in Australian schools

Children with intellectual disability are more vulnerable to adverse developmental outcomes because of the lifelong risks associated with cognitive impairment. Difficulties with learning and adaptive behaviour inevitably produce considerable personal, social and economic disadvantage. Of concern is consistent evidence that psychiatric disorders affect a substantial proportion of people with intellectual disability. The estimated prevalence rate of between 35 and 49 % is three times that found in the general population (Wallander, Dekker, & Koot, 2006). Until recently, mental illness has been relatively neglected for people with intellectual disability, especially in relation to prevention or early detection (Kolaitis, 2008) and most research to date has been descriptive rather than focused on intervention (Bouras, 2013). Yet a considerable body of evidence demonstrates that efficacious interventions do exist for preventing psychopathology and enhancing resilience in typically developing children and adolescents (see Mallin, Walker, & Levin, 2013 for a review). In order to prevent the high comorbidity of intellectual disability and psychopathology, there is a compelling need for evidence-based practices that promote the resilience of individuals with intellectual disability (Matson, Terlonge, & Minshawi, 2008). In this chapter, we describe a randomized controlled trial of an intervention that was designed to enhance the resilience of a group of children with mild intellectual disability as they prepared to make the transition to high school. We report results from our evaluation of this intervention, and reflect on the difficulties of providing successful interventions for children whose lives are complicated not only by intellectual disability, but also by a range of contextual disadvantages.

Mechanisms of change in psychotherapy for people diagnosed with schizophrenia : the role of narrative reflexivity in promoting recovery

Narrative reflexivity was investigated as a potential mechanism of therapeutic change during a 12 - 18 month trial of Metacognitive Narrative Psychotherapy for people diagnosed with schizophrenia. Participants were nine adult clients (8 male, 1 female) aged between 25-65 years (M = 44, SD = 12.76) with a diagnosis of schizophrenia consistent with DSM-IV criteria and seven female provisional psychologists aged between 25-29 years (M = 26.8 years, SD = 1.47 years). Recovery and narrative reflexivity were measured at three time points using the Recovery Assessment Scale (RAS) and the Narrative Processes Coding System (NPCS). Results were reported descriptively due to limited sample size (n = 9). The majority of clients (n = 7) reported an increase in recovery over the course of treatment. For six clients, an overall increase in recovery was associated with an increase in narrative reflexivity. This study provides preliminary support for narrative reflexivity as a potential mechanism of therapeutic change in the psychotherapy of people diagnosed with schizophrenia.

6 versus 12 month performance of polycaprolactone-based scaffold plus recombinant human morphogenetic protein-2 (rhBMP-2) in an ovine thoracic interbody fusion model

Introduction Well-designed biodegradable scaffolds in combination with bone growth factors offer a valuable alternative to the current gold standard autograft in spinal fusion surgery Yong et al. (2013). Here we report on 6- vs 12- month data set evaluating the longitudinal performance of a CaP coated polycaprolactone (PCL) scaffold loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute within a large preclinical animal model. Methods Twelve sheep underwent a 3-level (T6/7, T8/9 and T10/11) discectomy with randomly allocated implantation of a different graft substitute at each of the three levels; (i) calcium phosphate (CaP) coated polycaprolactone based scaffold plus 0.54µg rhBMP-2, (ii) CaP coated PCL- based scaffold alone or (iii) autograft (mulched rib head). Fusion assessments were performed via high resolution clinical computed tomography and histological evaluation were undertaken at six (n=6) and twelve (n=6) months post-surgery using the Sucato grading system (Sucato et al. 2004). Results The computed tomography fusion grades of the 6- and 12- months in the rhBMP-2 plus PCL- based scaffold group were 1.9 and 2.1 respectively, in the autograft group 1.9 and 1.3 respectively, and in the scaffold alone group 0.9 and 1.17 respectively. There were no statistically significant differences in the fusion scores between 6- and 12- month for the rhBMP plus PCL- based scaffold or PCL – based scaffold alone group however there was a significant reduction in scores in the autograft group. These scores were seen to correlate with histological evaluations of the respective groups. Conclusions The results of this study demonstrate the efficacy of scaffold-based delivery of rhBMP-2 in promoting higher fusion grades at 6- and 12- months in comparison to the scaffold alone or autograft group within the same time frame. Fusion grades achieved at six months using PCL+rhBMP-2 are not significantly increased at twelve months post-surgery.

Overexpression of the kiwifruit SVP3 gene affects reproductive development and suppresses anthocyanin biosynthesis in petals, but has no effect on vegetative growth, dormancy, or flowering time

SVP-like MADS domain transcription factors have been shown to regulate flowering time and both inflorescence and flower development in annual plants, while having effects on growth cessation and terminal bud formation in perennial species. Previously, four SVP genes were described in woody perennial vine kiwifruit (Actinidia spp.), with possible distinct roles in bud dormancy and flowering. Kiwifruit SVP3 transcript was confined to vegetative tissues and acted as a repressor of flowering as it was able to rescue the Arabidopsis svp41 mutant. To characterize kiwifruit SVP3 further, ectopic expression in kiwifruit species was performed. Ectopic expression of SVP3 in A. deliciosa did not affect general plant growth or the duration of endodormancy. Ectopic expression of SVP3 in A. eriantha also resulted in plants with normal vegetative growth, bud break, and flowering time. However, significantly prolonged and abnormal flower, fruit, and seed development were observed, arising from SVP3 interactions with kiwifruit floral homeotic MADS-domain proteins. Petal pigmentation was reduced as a result of SVP3-mediated interference with transcription of the kiwifruit flower tissue-specific R2R3 MYB regulator, MYB110a, and the gene encoding the key anthocyanin biosynthetic step, F3GT1. Constitutive expression of SVP3 had a similar impact on reproductive development in transgenic tobacco. The flowering time was not affected in day-neutral and photoperiod-responsive Nicotiana tabacum cultivars, but anthesis and seed germination were significantly delayed. The accumulation of anthocyanin in petals was reduced and the same underlying mechanism of R2R3 MYB NtAN2 transcript reduction was demonstrated.

Institutional determinants of growth-aspiration entrepreneurship

The thesis is a country-level study on the institutional and human capital determinants of growth-aspiration entrepreneurial activity. By using country-level panel-data analysis, the study is to our knowledge the first to test to what extent country-level human capital accumulation is associated with the prevalence of growth-aspiration entrepreneurship. Overall findings of the study suggest that there are different effects of the institutional determinants on the prevalence of growth-aspiration entrepreneurship in developing countries and developed countries. The study also found that country-level human capital moderates the effects of the institutional environment.

MicroRNAs targeting mutant K-ras by electrotransfer inhibit human colorectal adenocarcinoma cell growth in vitro and in vivo

Mutations of K-ras have been found in 30-60% of colorectal carcinomas and are believed to be associated with tumor initiation, tumor progression and metastasis formation. Therefore, silencing of mutant K-ras expression has become an attractive therapeutic strategy for colorectal cancer treatment. The aim of our study was to investigate the effect of microRNA (miRNA) molecules directed against K-ras (miRNA-K-ras) on K-ras expression level and the growth of colorectal carcinoma cell line LoVo in vitro and in vivo. In addition, we evaluated electroporation as a gene delivery method for transfection of LoVo cells and tumors with plasmid DNA encoding miRNA-K-ras (pmiRNA-K-ras). Results of our study indicated that miRNAs targeting K-ras efficiently reduced K-ras expression and cell survival after in vitro electrotransfection of LoVo cells with pmiRNA-K-ras. In vivo, electroporation has proven to be a simple and efficient delivery method for local administration of pmiRNA-K-ras molecules into LoVo tumors. This therapy shows pronounced antitumor effectiveness and has no side effects. The obtained results demonstrate that electrogene therapy with miRNA-K-ras molecules can be potential therapeutic strategy for treatment of colorectal cancers harboring K-ras mutations. © 2010 Nature Publishing Group All rights reserved.

Carbon nanorods and graphene-like nanosheets by hot filament CVD : growth mechanisms and electron field emission

Carbon nanorods and graphene-like nanosheets are catalytically synthesized in a hot filament chemical vapor deposition system with and without plasma enhancement, with gold used as a catalyst. The morphological and structural properties of the carbon nanorods and nanosheets are investigated by field-emission scanning electron microscopy, transmission electron microscopy and micro-Raman spectroscopy. It is found that carbon nanorods are formed when a CH4 + H2 + N2 plasma is present while carbon nanosheets are formed in a methane environment without a plasma. The formation of carbon nanorods and carbon nanosheets are analyzed. The results suggest that the formation of carbon nanorods is primarily a precipitation process while the formation of carbon nanosheets is a complex process involving surface-catalysis, surface diffusion and precipitation influenced by the Gibbs–Thomson effect. The electron field emission properties of the carbon nanorods and graphene-like nanosheets are measured under high-vacuum; it is found that the carbon nanosheets have a lower field emission turn-on than the carbon nanorods. These results are important to improve the understanding of formation mechanisms of carbon nanomaterials and contribute to eventual applications of these structures in nanodevices.

Size- and orientation-selective Si nanowire growth : thermokinetic effects of naeoscale plasma chemistry

A multiscale, multiphase thermokinetic model is used to show the effective control of the growth orientation of thin Si NWs for nanoelectronic devices enabled by nanoscale plasma chemistry. It is shown that very thin Si NWs with [110] growth direction can nucleate at much lower process temperatures and pressures compared to thermal chemical vapor deposition where [111]-directed Si NWs are predominantly grown. These findings explain a host of experimental results and offer the possibility of energy- and matter-efficient, size- and orientation-controlled growth of [110] Si NWs for next-generation nanodevices.

Plasma effects in semiconducting nanowire growth

Three case studies are presented to show low-temperature plasma-specific effects in the solution of (i) effective control of nucleation and growth; (ii) environmental friendliness; and (iii) energy efficiency critical issues in semiconducting nanowire growth. The first case (related to (i) and (iii)) shows that in catalytic growth of Si nanowires, plasma-specific effects lead to a substantial increase in growth rates, decrease of the minimum nanowire thickness, and much faster nanowire nucleation at the same growth temperatures. For nucleation and growth of nanowires of the same thickness, much lower temperatures are required. In the second example (related to (ii)), we produce Si nanowire networks with controllable nanowire thickness, length, and area density without any catalyst or external supply of Si building material. This case is an environmentally-friendly alternative to the commonly used Si microfabrication based on a highly-toxic silane precursor gas. The third example is related to (iii) and demonstrates that ZnO nanowires can be synthesized in plasma-enhanced CVD at significantly lower process temperatures than in similar neutral gas-based processes and without compromising structural quality and performance of the nanowires. Our results are relevant to the development of next-generation nanoelectronic, optoelectronic, energy conversion and sensing devices based on semiconducting nanowires.

Copper-capped carbon nanocones on silicon : plasma-enabled growth control

Controlled self-organized growth of vertically aligned carbon nanocone arrays in a radio frequency inductively coupled plasma-based process is studied. The experiments have demonstrated that the gaps between the nanocones, density of the nanocone array, and the shape of the nanocones can be effectively controlled by the process parameters such as gas composition (hydrogen content) and electrical bias applied to the substrate. Optical measurements have demonstrated lower reflectance of the nanocone array as compared with a bare Si wafer, thus evidencing their potential for the use in optical devices. The nanocone formation mechanism is explained in terms of redistribution of surface and volumetric fluxes of plasma-generated species in a developing nanocone array and passivation of carbon in narrow gaps where the access of plasma ions is hindered. Extensive numerical simulations were used to support the proposed growth mechanism.

Plasma-enabled, catalyst-free growth of carbon nanotubes on mechanically-written Si features with arbitrary shape

Simple, rapid, catalyst-free synthesis of complex patterns of long, vertically aligned multiwalled carbon nanotubes, strictly confined within mechanically-written features on a Si(1 0 0) surface is reported. It is shown that dense arrays of the nanotubes can nucleate and fully fill the features when the low-temperature microwave plasma is in a direct contact with the surface. This eliminates additional nanofabrication steps and inevitable contact losses in applications associated with carbon nanotube patterns. Using metal catalyst has long been considered essential for the nucleation and growth of surface-supported carbon nanotubes (CNTs) [1] and [2]. Only very recently, the possibility of CNT growth using non-metallic (e.g., oxide [3] and SiC [4]) catalysts or artificially created carbon-enriched surface layers [5] has been demonstrated. However, successful integration of carbon nanostructures into Si-based nanodevice platforms requires catalyst-free growth, as the catalyst nanoparticles introduce contact losses, and their catalytic activity is very difficult to control during the growth [6]. Furthermore, in many applications in microfluidics, biological and molecular filters, electronic, sensor, and energy conversion nanodevices, the CNTs need to be arranged in specific complex patterns [7] and [8]. These patterns need to contain the basic features (e.g., lines and dots) written using simple procedures and fully filled with dense arrays of high-quality, straight, yet separated nanotubes. In this paper, we report on a completely metal or oxide catalyst-free plasma-based approach for the direct and rapid growth of dense arrays of long vertically-aligned multi-walled carbon nanotubes arranged into complex patterns made of various combinations of basic features on a Si(1 0 0) surface written using simple mechanical techniques. The process was conducted in a plasma environment [9] and [10] produced by a microwave discharge which typically generates the low-temperature plasmas at the discharge power below 1 kW [11]. Our process starts from mechanical writing (scribing) a pattern of arbitrary features on pre-treated Si(1 0 0) wafers. Before and after the mechanical feature writing, the Si(1 0 0) substrates were cleaned in an aqueous solution of hydrofluoric acid for 2 min to remove any possible contaminations (such as oil traces which could decompose to free carbon at elevated temperatures) from the substrate surface. A piece of another silicon wafer cleaned in the same way as the substrate, or a diamond scriber were used to produce the growth patterns by a simple arbitrary mechanical writing, i.e., by making linear scratches or dot punctures on the Si wafer surface. The results were the same in both cases, i.e., when scratching the surface by Si or a diamond scriber. The procedure for preparation of the substrates did not involve any possibility of external metallic contaminations on the substrate surface. After the preparation, the substrates were loaded into an ASTeX model 5200 chemical vapour deposition (CVD) reactor, which was very carefully conditioned to remove any residue contamination. The samples were heated to at least 800 °C to remove any oxide that could have formed during the sample loading [12]. After loading the substrates into the reactor chamber, N2 gas was supplied into the chamber at the pressure of 7 Torr to ignite and sustain the discharge at the total power of 200 W. Then, a mixture of CH4 and 60% of N2 gases were supplied at 20 Torr, and the discharge power was increased to 700 W (power density of approximately 1.49 W/cm3). During the process, the microwave plasma was in a direct contact with the substrate. During the plasma exposure, no external heating source was used, and the substrate temperature (∼850 °C) was maintained merely due to the plasma heating. The features were exposed to a microwave plasma for 3–5 min. A photograph of the reactor and the plasma discharge is shown in Fig. 1a and b.

Kinetics of low-pressure, low-temperature graphene growth : toward single-layer, single-crystalline structure

Graphene grown on metal catalysts with low carbon solubility is a highly competitive alternative to exfoliated and other forms of graphene, yet a single-layer, single-crystal structure remains a challenge because of the large number of randomly oriented nuclei that form grain boundaries when stitched together. A kinetic model of graphene nucleation and growth is developed to elucidate the effective controls of the graphene island density and surface coverage from the onset of nucleation to the full monolayer formation in low-pressure, low-temperature CVD. The model unprecedentedly involves the complete cycle of the elementary gas-phase and surface processes and shows a precise quantitative agreement with the recent low-energy electron diffraction measurements and also explains numerous parameter trends from a host of experimental reports. These agreements are demonstrated for a broad pressure range as well as different combinations of precursor gases and supporting catalysts. The critical role of hydrogen in controlling the graphene nucleation and monolayer formation is revealed and quantified. The model is generic and can be extended to even broader ranges of catalysts and precursor gases/pressures to enable the as yet elusive effective control of the crystalline structure and number of layers of graphene using the minimum amounts of matter and energy.

Plasma-enabled growth of single-crystalline SiC/AlSiC Core–Shell nanowires on porous alumina templates

We report the catalyst-free synthesis of the arrays of core–shell, ultrathin, size-uniform SiC/AlSiC nanowires on the top of a periodic anodic aluminum oxide template. The nanowires were grown using an environmentally friendly, silane-free process by exposing the silicon supported porous alumina template to CH4 + H2 plasmas. High-resolution scanning and transmission electron microscopy studies revealed that the nanowires have a single-crystalline core with a diameter of about 10 nm and a thin (1–2 nm) amorphous AlSiC shell. Because of their remarkable length, high aspect ratio, and very high surface area-to-volume ratio, these unique structures are promising for nanoelectronic and nanophotonic applications that require efficient electron emission, light scattering, etc. A mechanism for nanowire growth is proposed based upon the reduction of the alumina template to nanosized metallic aluminum droplets forming between nanopores. The subsequent incorporation of silicon and carbon atoms from the plasma leads to nucleation and growth from the top of the alumina template.

Rapid, simultaneous activation of thin nanowire growth in low-temperature, low-pressure chemically active plasmas

Multiscale numerical modeling of the species balance and transport in the ionized gas phase and on the nanostructured solid surface complemented by the heat exchange model is used to demonstrate the possibility of minimizing the Gibbs-Thompson effect in low-temperature, low-pressure chemically active plasma-assisted growth of uniform arrays of very thin Si nanowires, impossible otherwise. It is shown that plasma-specific effects drastically shorten and decrease the dispersion of the incubation times for the nucleation of nanowires on non-uniform Au catalyst nanoparticle arrays. The fast nucleation makes it possible to avoid a common problem of small catalyst nanoparticle burying by amorphous silicon. These results explain a multitude of experimental observations on chemically active plasma-assisted Si nanowire growth and can be used for the synthesis of a range of inorganic nanowires for environmental, biomedical, energy conversion, and optoelectronic applications.