Long-run validity of purchasing power parity and rank tests for cointegration for Central Asian Countries

This study finds that Purchasing Power Parity holds in the long-run for Azerbaijan, Kazakhstan and Kyrgyzstan, based on Breitung’s (2001) rank tests for cointegration. Results from further analysis indicates that nominal exchange rates and relative prices are nonlinearly interrelated. Trade barriers, transportation costs and government intervention in the pricing system in these countries may have resulted in the establishment of the above-mentioned nonlinear relationship.Purchasing power parity; Cointegration; Nonlinear; Rank tests; Central Asia.

Applying Neural Networks to Prices Prediction of Crude Oil Futures

The global economy experienced turbulent uneasiness for the past five years owing to large increases in oil prices and terrorist’s attacks. While accurate prediction of oil price is important but extremely difficult, this study attempts to accurately forecast prices of crude oil futures by adopting three popular neural networks methods including the multilayer perceptron, the Elman recurrent neural network (ERNN), and recurrent fuzzy neural network (RFNN). Experimental results indicate that the use of neural networks to forecast the crude oil futures prices is appropriate and consistent learning is achieved by employing different training times. Our results further demonstrate that, in most situations, learning performance can be improved by increasing the training time. Moreover, the RFNN has the best predictive power and the MLP has the worst one among the three underlying neural networks. This finding shows that, under ERNNs and RFNNs, the predictive power improves when increasing the training time. The exceptional case involved BPNs, suggesting that the predictive power improves when reducing the training time. To sum up, we conclude that the RFNN outperformed the other two neural networks in forecasting crude oil futures prices

Additive manufacture of three dimensional nanocomposite based objects through multiphoton fabrication

Three dimensional structures prepared from a gold-polymer composite formulation have been fabricated using multiphoton lithography. In this process, gold nanoparticles were simultaneously formed through photoreduction whilst polymerisation of two possible monomers was promoted. The monomers, trimethylopropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA) were mixed with a gold salt, but it was found that the addition of a Ruthenium (II) complex enhanced both the geometrical uniformity and integrity of the polymerized / reduced material, enabling the first production of 3D gold-polymer structures by single step multiphoton lithography

Structural effects of inosine substitution in telomeric DNA quadruplex

The telomeric DNA, a distal region of eukaryotic chromosome containing guanine-rich repetitive sequence of (TTAGGG)n, has been shown to adopt higher-order structures, specifically G-quadruplexes (G4s). Previous studies have demonstrated the implication of G4 in tumor inhibition through chromosome maintenance and manipulation of oncogene expression featuring their G-rich promoter regions. Besides higher order structures, several regulatory roles are attributed to DNA epigenetic markers. In this work, we investigated how the structural dynamics of a G-quadruplex, formed by the telomeric sequence, is affected by inosine, a prevalent modified nucleotide. We used the standard (TTAGGG)n telomere repeats with guanosine mutated to inosine at each G position. Sequences (GGG)4, (IGG)4, (GIG)4, (GGI)4, (IGI)4, (IIG)4, (GII)4, and (III)4, bridged by TTA linker, are studied using biophysical experiments and molecular modeling. The effects of metal cations in quadruplex folding were explored in both Na+ and K+ containing buffers using CD and UV-melting studies. Our results show that antiparallel quadruplex topology forms with the native sequence (GGG)4 and the terminal modified DNAs (IGG)4 and (GGI)4 in both Na+ and K+ containing buffers. Specifically, quadruplex hybrid was observed for (GGG)4 in K+ buffer. Among the other modified sequences, (GIG)4, (IGI)4 and (GII)4 show parallel features, while (IIG)4 and (III)4 show no detectable conformation in the presence of either Na+ or K+. Our studies indicate that terminal lesions (IGG)4 and (GGI)4 may induce certain unknown conformations. The folding dynamics become undetectable in the presence of more than one inosine substitution except (IGI)4 in both buffer ions. In addition, both UV melting and CD melting studies implied that in most cases the K+ cation confers more thermodynamic stability compared to Na+. Collectively, our conformational studies revealed the diverse structural polymorphisms of G4 with position dependent G-to-I mutations in different ion conditions

Author Correction: Additive manufacture of complex 3D Au-containing nanocomposites by simultaneous two-photon polymerisation and photoreduction

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A Soluble ‘Ba(Ni-ett)’ (ett = 1,1,2,2-Ethenetetrathiolate) Derived Thermoelectric Material

We describe the synthesis and characterisation of the first of a new class of soluble ladder oligomeric thermoelectric material based on previously unutilised ethene-1,1,2,2-tetrasulfonic acid. Reaction of Ba(OH)2 and propionic acid at a 1:1 stoichiometry leads to the formation of the previously unrecognised soluble [Ba(OH)(O2CEt)]⋅H2O. The latter when used to hydrolyse 1,3,4,6-tetrathiapentalene-2,5-dione (TPD), in the presence of NiCl2, forms a new material whose elemental composition is in accord with the formula [(EtCO2Ba)4Ni8{(O3S)2C = C(SO3)2}5]⋅22H2O (4). Compound 4 can be pressed into pellets, drop-cast as DMSO solutions or ink-jet printed (down to sub-mm resolutions). While its room temperature thermoelectric properties are modest (σmax 0.04 S cm−1 and Seebeck coefficient, αmax − 25.8 μV K−1) we introduce a versatile new oligomeric material that opens new possible synthetic routes for n-type thermoelectrics

The influence of printing parameters on multi-material two-photon polymerisation based micro additive manufacturing

Two-photon polymerisation (2PP) based additive manufacturing has emerged as a powerful technology to fabricate complex three-dimensional micro- and nanoscale architectures. However, a comprehensive understanding of the effect of printing parameters on the functional properties of these structures is needed to unleash the potential of 2PP and enable controlled deposition / integration of various materials into multi-material structures. In this study we investigate the correlation between printing parameters, resin composition and the final properties of 2PP structures fabricated with different monomers and initiators. The link between 2PP process and final material properties is validated by morphological studies, vibrational spectroscopy and advanced mass spectrometry, ToF-SIMS, imaging. We establish empirical relationships between printing parameters and mechanical properties, and achieve controlled deposition of different monomers with high precision and uniform composition. The approaches developed here are successfully used to demonstrate multi-material 2PP and produce complex 3D architectures incorporating three polymers. The 2PP structures produced can be transferred into solution or onto different substrates, in addition to direct fabrication on flexible substrates. This work advances the understanding of the 2PP process, which enable rational design and manufacture of complex geometries and additive manufacturing of nanoscale multi-material structures