Learning or Leaning: Persistent and Transitory Spillovers from FDI

Using firm-level data for Jordan, we estimate the extent to which growth spillovers from foreign direct investment (FDI) to local firms stem from persistent learning externalities (i.e., they endure even after foreign investment leaves as knowledge has been transferred to local firms) or from transitory effects (e.g., demand increases which evaporate following disinvestment). We find that they have a significant transitory nature, with employment and capital growth declining when FDI falls, particularly in downstream industries supplied by locals. This suggests that if FDI-attracting policies are intended to promote sustainable growth, it may be more effective to attract and retain FDI via long-term structural policies, for instance, through low corporate tax rates rather than temporary tax holidays or through policies that strengthen the domestic absorptive capacity and linkages between foreign and local firms. It also suggests that FDI-led growth can increase a country's vulnerability to adverse global shocks in that the productivity gains of domestic firms will be partly reversed with the disinvestment of multinational firms

Structure-mechanics relationships of collagen fibrils in the Osteogenesis Imperfecta Mouse model

The collagen molecule, which is the building block of collagen fibrils, is a triple helix of two α1(I) chains and one α2(I) chain. However, in the severe mouse model of osteogenesis imperfecta (OIM), deletion of the COL1A2 gene results in the substitution of the α2(I) chain by one α1(I) chain. As this substitution severely impairs the structure and mechanics of collagen-rich tissues at the tissue and organ level, the main aim of this study was to investigate how the structure and mechanics are altered in OIM collagen fibrils. Comparing results from atomic force microscopy imaging and cantilever-based nanoindentation on collagen fibrils from OIM and wild-type (WT) animals, we found a 33% lower indentation modulus in OIM when air-dried (bound water present) and an almost fivefold higher indentation modulus in OIM collagen fibrils when fully hydrated (bound and unbound water present) in phosphate-buffered saline solution (PBS) compared with WT collagen fibrils. These mechanical changes were accompanied by an impaired swelling upon hydration within PBS. Our experimental and atomistic simulation results show how the structure and mechanics are altered at the individual collagen fibril level as a result of collagen gene mutation in OIM. We envisage that the combination of experimental and modelling approaches could allow mechanical phenotyping at the collagen fibril level of virtually any alteration of collagen structure or chemistry.United States. Dept. of Defense. Presidential Early Career Award for Scientists and EngineersNational Science Foundation (U.S.) (CAREER Award

Electromagnetic Actuated stirring in Microbioreactors enabling easier multiplexing & flexible device design

This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.The development of a novel electromagnetically (EM) actuated stirring method, for use in microbioreactors, is reported. Mixing in microbioreactors is critical to ensure even distribution of nutrients to microorganisms and cells. Magnetically driven stirrer bars or peristaltic mixing are the most commonly utilised mixing methods employed in completely liquid-filled microbioreactors. However the circular reactor shape required for mixing with a stirrer bar and frequently used for peristaltically mixed microbioreactors presents difficulties for bubble-free priming in a microfluidic bioreactor. Moreover the circular shape and the hardware required for both types of mixing reduces the potential packing density of multiplexed reactors. We present a new method of mixing, displaying design flexibility by demonstrating mixing in circular and diamond-shaped reactors and a duplex diamond reactor and fermentation of the gram-positive bacteria S. carnosus in a diamond-shaped microbioreactor system. The results of the optimisation of this mixing method for performing fermentations alongside both batch and continuous culture fermentations are presented

Metastable Flux Configurations and de Sitter Spaces

We derive stability conditions for the critical points of the no-scale scalar potential governing the dynamics of the complex structure moduli and the axio-dilaton in compactifications of type IIB string theory on Calabi-Yau three-folds. We discuss a concrete example of a T^6 orientifold. We then consider the four-dimensional theory obtained from compactifications of type IIB string theory on non-geometric backgrounds which are mirror to rigid Calabi-Yau manifolds and show that the complex structure moduli fields can be stabilized in terms of H_{RR} only, i.e. with no need of orientifold projection. The stabilization of all the fields at weak coupling, including the axio-dilaton, may require to break supersymmetry in the presence of H_{NS} flux or corrections to the scalar potential.Comment: 24 page

The effects of Si-doped prelayers on the optical properties of InGaN/GaN single quantum well structures

In this paper, we report on the effects of including Si-doped (In)GaN prelayers on the low temperature optical properties of a blue-light emitting InGaN/GaN single quantum well. We observed a large blue shift of the photoluminescence peak emission energy and significant increases in the radiative recombination rate for the quantum well structures that incorporated Si-doped prelayers. Simulations of the variation of the conduction and valence band energies show that a strong modification of the band profile occurs for the quantum wells on Si-doped prelayers due to an increase in strength of the surface polarization field. The enhanced surface polarization field opposes the built-in field across the quantum well and thus reduces this built-in electric field. This reduction of the electric field across the quantum well reduces the Quantum Confined Stark Effect and is responsible for the observed blue shift and the change in the recombination dynamics.This work was carried out with the financial support of the United Kingdom Engineering and Physical Sciences Research Council under Grant Nos. EP/I012591/1 and EP/ H011676/1.This is the accepted manuscript version of the article. The final version is available from AIP at http://scitation.aip.org/content/aip/journal/apl/105/9/10.1063/1.4894834

Found: High Surface Brightness Compact Galaxies

We are using the 2dF spectrograph to make a survey of all objects (`stars' and `galaxies') in a 12 sq.deg region towards the Fornax cluster. We have discovered a population of compact emission-line galaxies unresolved on photographic sky survey plates and therefore missing in most galaxy surveys based on such material. These galaxies are as luminous as normal field galaxies. Using H-alpha to estimate star formation they contribute at least an additional 5 per cent to the local star formation rate.Comment: To appear in "The Low Surface Brightness Universe", IAU Coll 171, eds. J.I. Davies et al., A.S.P. Conference Series. 3 pages, LaTex, 1 encapsulated ps-figure, requires paspconf.st

A comparison of the optical properties of InGaN/GaN multiple quantum well structures grown with and without Si-doped InGaN prelayers

In this paper, we report on a detailed spectroscopic study of the optical properties of InGaN/GaN multiple quantum well structures, both with and without a Si-doped InGaN prelayer. In photoluminescence and photoluminescence excitation spectroscopy, a 2nd emission band, occurring at a higher energy, was identified in the spectrum of the multiple quantum well structure containing the InGaN prelayer, originating from the first quantum well in the stack. Band structure calculations revealed that a reduction in the resultant electric field occurred in the quantum well immediately adjacent to the InGaN prelayer, therefore leading to a reduction in the strength of the quantum confined Stark effect in this quantum well. The partial suppression of the quantum confined Stark effect in this quantum well led to a modified (higher) emission energy and increased radiative recombination rate. Therefore, we ascribed the origin of the high energy emission band to recombination from the 1st quantum well in the structure. Study of the temperature dependent recombination dynamics of both samples showed that the decay time measured across the spectrum was strongly influenced by the 1st quantum well in the stack (in the sample containing the prelayer) leading to a shorter average room temperature lifetime in this sample. The room temperature internal quantum efficiency of the prelayer containing sample was found to be higher than the reference sample (36% compared to 25%) which was thus attributed to the faster radiative recombination rate of the 1st quantum well providing a recombination pathway that is more competitive with non-radiative recombination processes.This work was carried out with the financial support of the United Kingdom Engineering and Physical Sciences Research Council under Grant Nos. EP/I012591/1 and EP/ H011676/1.This is the final version of the article. It first appeared from AIP Publishing via http://dx.doi.org/10.1063/1.494132

Crystallisation of Aspirin via Simulated Pulmonary Surfactant Monolayers and Lung-Specific Additives

Pain is a prevalent condition that can have a serious impact upon the socioeconomic function of a population. Numerous methods exist to administer analgesic medication (e.g. aspirin) to the body however inherent drawbacks limit patient acceptability. The inhaled route offers promise to facilitate the administration of medication to the body. Here, we consider the crystallisation behaviour of aspirin, our model therapeutic agent, when in contact with material of relevance to the lung. Thus, our approach aims to better understand the interaction between drug substances and the respiratory tract. Langmuir monolayers composed of a mixed surfactant system were supported on an aqueous subphase containing aspirin (7.5mg/ml). The surfactant film was compressed to either 5mN/m (i.e. inhalation end point) or 50mN/m (i.e. exhalation end point), whilst located within a humid environment for 16 hours. Standard cooling crystallisation procedures were employed to produce control samples. Antisolvent crystallisation in the presence or absence of lung-specific additives was conducted. All samples were analysed via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Drug-surfactant interactions were confirmed via condensed Langmuir isotherms. SEM analysis revealed plate-like morphology. The crystallisation route dictated both the crystal habit and particle size distribution. Dominant reflections were the (100) and (200) aspects. The main modes of interaction were hydrogen bonding, hydrophobic associations and van der Waals forces. Here, we have demonstrated the potential of antisolvent crystallisation with lung-specific additives to achieve control over drug crystal morphology. The approach taken can be applied in respirable formulation engineering

On drug-base incompatibilities during extrudate manufacture and fused deposition 3D printing

Aim: 3D printing can be applied for point-of-care personalized treatment. This study aimed to determine the manufacturability and characteristics of 3D printed, drug loaded implants for alcohol misuse. Materials & methods: Disulfiram was the drug substance used and polylactic acid (PLA) the base material. Implantable devices were designed in silico. Drug and PLA were placed into the extruder to produce a 5% blend at 1.75-mm diameter. Material characterization included differential scanning calorimetry, thermogravimetric analysis plus inverse GC-surface energy analyzer. Results: Implantable constructs from the PLA feedstock were acquired. The extrusion processes had a detrimental effect on the active pharmaceutical ingredient-base blend. differential scanning calorimetry and thermogravimetric analysis analysis indicated drug–base interactions. Thermal history was found to influence inverse GC probe interaction. Conclusion: Drug-base incompatibilities must be considered during 3D printing

Flocculation on a chip: a novel screening approach to determine floc growth rates and select flocculating agents

Flocculation is a key purification step in cell-based processes for the food and pharmaceutical industry where the removal of cells and cellular debris is aided by adding flocculating agents. However, finding the best suited flocculating agent and optimal conditions to achieve rapid and effective flocculation is a nontrivial task. In conventional analytical systems, turbulent mixing creates a dynamic equilibrium between floc growth and breakage, constraining the determination of floc formation rates. Furthermore, these systems typically rely on end-point measurements only. We have successfully developed for the first time a microfluidic system for the study of flocculation under well controlled conditions. In our microfluidic device (μFLOC), floc sizes and growth rates were monitored in real time using high-speed imaging and computational image analysis. The on-line and in situ detection allowed quantification of floc sizes and their growth kinetics. This eliminated the issues of sample handling, sample dispersion, and end-point measurements. We demonstrated the power of this approach by quantifying the growth rates of floc formation under forty different growth conditions by varying industrially relevant flocculating agents (pDADMAC, PEI, PEG), their concentration and dosage. Growth rates between 12.2 μm s−1 for a strongly cationic flocculant (pDADMAC) and 0.6 μm s−1 for a non-ionic flocculant (PEG) were observed, demonstrating the potential to rank flocculating conditions in a quantitative way. We have therefore created a screening tool to efficiently compare flocculating agents and rapidly find the best flocculating condition, which will significantly accelerate early bioprocess development