Economic growth in Sub-Saharan Africa (SSA) has averaged roughly 5 percent per year over the past decade, improving living standards and bolstering human development indicators across the continent. Stronger public institutions, a supportive, private sector–focused policy environment, responsible macroeconomic management, and a sustained commitment to structural reforms have greatly expanded opportunities for countries in SSA to participate in global markets. In recent years, many countries in the region have benefited from an increasingly favorable external environment, high commodity prices, and an especially strong demand for natural resources by emerging economies, particularly China. Over the longer term, leveraging Chinese investment to support broad-based growth will require policies designed to boost the competitiveness of sectors in which China’s economic rebalancing may create a comparative advantage for SSA. To date, few African countries have been able to benefit from large-scale Chinese investment outside the resource sector. However, as China’s growth slows and its economy shifts toward a more consumption-driven model, it is likely that global demand for resource imports will slow as well. Countries with the most heavily concentrated export mix, particularly in the mineral and oil sectors are the most vulnerable to China’s economic rebalancing and should be ready to adopt measures to mitigate the impact of negative terms-of-trade shocks. By contrast, as wage rates in China continue to rise and firms refocus their attention on domestic demand, countries in SSA will be well positioned to exploit emerging opportunities for investment in export-oriented manufacturing. Ethiopia provides an instructive example, as its inexpensive yet relatively skilled labor force, coupled with the government’s proactive efforts to court Chinese investors, have enabled Ethiopia to attract substantial investments in labor-intensive industries. Infrastructure enhancement, workforce development, and good-governance reforms offer a promising strategy for many countries in the region. Although the establishment of industrial zones has yielded mixed results, several salient success stories warrant careful attention. This report discusses how Africa could take advantage of the untapped opportunities offered by China’s progressively intensifying investment and trade ties with SSA. It is hoped that this analysis will enrich the ongoing dialogue between policy makers, private firms, and civil society regarding China’s increasingly important role in the growth and development of Sub-Saharan Africa.

This article presents laser interference lithography, a preferred method to achieve periodic structures in a large area with fast speed and low cost. Simulations and experiments for two-beam interference lithography with single exposure and double exposure were expressed. In the experiments, patterns on photoresist were transferred to a silicon substrate by wet etching. The experimental results were consistent with the simulative results. The one-dimensional nanogrooves were obtained by single exposure, and different widths of nanogrooves during the same period were fabricated on silicon substrates by varying exposure time. In addition, two-dimensional grid patterns were obtained by double exposure. With the increasing of exposure time, the grid pattern changed from a nanoholes array to a nanodots array. The results showed that laser interference lithography is an efficient method to fabricate nanostructures with various geometrical parameters by controlling exposure time, which has a promising application in the study of nanotextured surface properties, such as wetting, adhesion and friction.

The electronic-controlling nanotribological behavior of textured silicon surfaces was investigated by an atomic force microscope (AFM), which were fabricated by laser interference lithography and chemical etching. The results indicated that without an external bias, friction on textured surfaces was greater than that on smooth surfaces and it was related to the coverage rate of the microgrooves. With an external bias, friction on smooth and textured surfaces decreased at first and then increased approximately linearly as the external bias increased.

Skin cream is commonly used to improve skin health and create a smooth, soft and moist perception by altering the surface roughness, friction, adhesion, elasticity and surface charging of skin surface. In this study, we present the first systematic study on friction, adhesion, durability and influence of humidity on adhesion and surface charging of skin and various skin creams using atomic force microscopy. Skin is subjected to various daily activities with time, and the durability is closely tied to product compositions. Durability of various skin creams was studied by repeated cycling tests. In order to better understand the frictional behaviour, the dynamic viscosities of various skin creams were measured. Skin cream thinly coats the skin surface and can cause drastic changes in the mechanical properties. In addition to mechanical properties, adhesive force is one of the important factors in determining the tactile perception of skin cream and is directly affected by the film thickness. Because the environmental dependence of skin and skin cream is of importance, the influence of humidity on adhesive force, film thickness and Young's modulus mapping were measured using force distance technique. The health and feel of skin are significantly affected by its surface charging, the surface potential of skin and various cream‐treated skins was measured using the Kelvin probe method.

The FTIR spectral measurements were carried out for native cytochrome c (cyt c) and its four platinum-modified derivatives. The influence of the platinum complex binding on the secondary structure of cyt c was discussed. It was found that the secondary structure of platinum-binded derivatives is similar to that of native cyt c when the platinum complex is binding on or near the surface of the protein. While in the case of derivatives, in which the platinum complex interacts with the second axial ligand of cyt c (Met 80) and causes the replacement of Met 80 by Lys 79 or solvent (H2O), great secondary structural changes were observed The results imply that the Met 80 residue is very important in controlling the secondary structure of cyt c.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Two coordination polymers [Ag(bib)]NO3.H2O (1) and [Ag(bib)]ClO4 (2) with one-dimensional (1D) chain structure were synthesized by reactions of ditopic ligand containing imidazole donors, namely, 1-bromo-3,5-bis(imidazol-1-ylmethyl)benzene (bib), with corresponding silver salts. While the bib ligand reacted with ditopic diacetato-zinc(II) acceptors, M2L2-type metallocyclic ring-like complex [Zn-2(bib)(2)(OAc)(4)].2H(2)O (OAc = acetate anion) (3) was obtained, which was further connected by Br...Br interactions to lead to the formation of 1D pseudo-polyrotaxane. When ligand bib reacted with Zn(NO3)(2).6H(2)O and Mn(NO3)(2), two complexes [Zn(bib)(2)(H2O)(2)](NO3)(2).2H(2)O (4) and [Mn(bib)(2)(H2O)(2)](NO3)(2).2H(2)O (5) with 2D network structure were obtained in which the metal atoms had octahedral coordination geometry. The structures of these coordination complexes were determined by X-ray crystallography, and the results revealed that the coordination geometry of metal atoms have a great impact on the structure of the supramolecular architectures. Furthermore, the nitrate anions located in the voids between the 2D cationic layers in 4 can be exchanged by nitrite anions, which means that complex 4 with 2D network structure has anion exchange properties.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The reaction between 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene (titmb) and [Ag(NH3)2][Hsal] (H2sal=salicylic acid) produces novel complex [Ag2(titmb)2][Hsal]2·3H2O (1). There are two unique silver centers in complex 1 with one serving as a trigonal node and the other one as a linear node. Interestingly, there are two sorts of titmb ligands in complex 1, one acting as a three-connecting ligand and the other one as a two-connecting (bridging) ligand. The silver centers are linked by titmb ligand to form 2D puckered layers containing M5(titmb)5 macrocyclic motifs, which is large enough to allow the bridging titmb ligands from the neighboring layers to be completely enclosed in. Namely, two neighboring independent layers interpenetrated each other in a parallel fashion without the occurrence of catenation to give a 3D structure.

A dinuclear Zn(II) complex with hexaaza macrocyclic ligand bearing two 2-hydroxypropyl pendants, 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxypropyl)-tricyclo [22,2,2,2(11,14)]triaconta-11,13,24,26,27,29-hexane (L) was synthesized and studied as a catalyst of the cleavage of 4-nitrophenyl acetate (NA). X-ray diffraction analysis of [Zn(2)LCl(2)]Cl(2)(.)6H(2)O revealed that Zn(II) adopts a trigonal-bipyramidal geometry. The complexation constants of L with Zn(II) have been determined at 298 K by means of potentiometric titration. [Zn(2)H(-2)L](2+) is the dominant species in aqueous solution around pH 8. The Zn(2)L-promoted hydrolysis of NA showed a second-order rate constant of 0.33 M(-1)s(-1) at pH 9.0, and the main promoter species are concluded to be the deprotonated species [Zn(2)H(-2)L](2+).

A dinuclear Cu-II complex containing a hexaaza macrocyclic ligand bearing two 2-hydroxypropyl pendants, 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxypropyl)tricyclo- [22.2.2.2(11,14)]triaconta-1,11,13,24,27,29-hexaene (L), was synthesized. The title complex [Cu-2(H-2L)Cl-2].6.5H(2)O was isolated as a blue crystal, orthorhombic, space group Fddd, with a = 16.4581(12), b = 32,248(2), c 35.830(2) Angstrom, V = 19017(2) Angstrom(3), Z = 16, R1 = 0.0690, and wR2 = 0.1546 [I > 2sigma(I)]. The protonation constants of Cu2L were determined by potentiometric titration, and it was found that the alcoholic hydroxypropyl group of the complex Cu2L exhibits low pK(a) values of pK(a1) = 7.31, pK(a2) = 7.83 at 25 degreesC. The hydrolysis kinetics of 4-nitrophenyl acetate (NA) promoted by the title complex have also been studied. The pH-rate profile for Cu2L gave a sigmoidal curve and showed a second-order rate constant of 0.39 +/- 0.02 m(-1) s(-1) in 10% CH3CN/H2O(v/v), which is greater than that of the dinuclear Cu-II complex formed by a hexaaza macrocycle without pendants, The reason for the higher catalytic activity of the title complex is discussed. Vie found that the volume of nucleophile RO- can effect the hydrolysis of the carboxy ester, the nucleophilicity of RO- and the Lewis acidity of the metal macrocycle also affect the carboxy ester hydrolysis. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

This paper presents the use of an equilibrium-based computer model to investigate the speciation of Al in soil solutions assumed to be in equilibrium with mineral phase jurbanite. The model predicts the distribution of various inorganic Al species, Al-organic matter complexes, and polymeric-Al species in solution as a function of pH. Using data from several published sources, the model demonstrates how change in soil solution composition impacts Al solution chemistry in equilbrium with several Al solid phases: jurbanite, basaluminite, alunite and gibbsite. Emphasis is placed on jurbanite due to its presence in soils impacted by acidic deposition. In the presence of jurbanite, the model predicts that SO42- will have a substantial influence on the distribution of Al species and concentrations. of soluble Al, while concentrations of organically complexed and fluoride complexed Al are minimal in the pH range studied. The model also predicts Al speciation for published soil solution data, assuming soil solutions were in equilibrium with jurbanite. Predicted concentrations of total dissolved Al, inorganic Al and Al-organic complexes agreed within an order of total dissolved Al, inorganic Al and Al-organic complexes agreed within an order of magnitude, however, the model consistently over predicts concentrations using the current set of constants. Nevertheless, the model results imply the presence and dissolution of jurbanite in soils impacted by acidic deposition will markedly influence soil solution Al chemistry.

A new coordination polymer [Cu(HBTC)(H2O)(1).(5)].H2O (2) was synthesized by reaction of CuSO4.5H(2)O with a mononuclear complex [Mn(H2BTC)(2)(H2O)(4)].2H(2)O (1) which was obtained by the reaction of MnSO4.H2O with 1,2, 4- benzenetricarboxylic acid (H3BTC). The complexes 1 and 2 were characterized by X-ray crystallography. In complex 1, each Mn(II) atom is coordinated by two H2BTC- units and four water molecules; while in complex 2, each Cu(II) atom is coordinated by three HBTC2- units and two water molecules, one of which acts as a bridge, to generate an infinite 2D network.

A new hexaaza macrocyclic ligand (L) bearing two 2-hydroxypropyl pendants, 6,19-bis(2-hydroxypropyl)-3,6,9,16,19,22-hexaaza-tricyclo-[22.2.2.211,14]triaconta-11,13,24,26,27,29-hexaene has been synthesized and characterized. The macrocyclic ligand was isolated as a colorless crystal, monoclinic, P2(1)/n, with a=10.757(2), b=14.214(3), c=13.746(3) Å, β=101.40(3)°, V=2060.3(7) Å3, Z=2, R1=0.0695, and wR2=0.1538 [I>2σ(I)]. Potentiometric studies of the macrocyclic ligand and three types of amino acids, glycine (equal numbers of carboxylate and amino groups), aspartic acid (more carboxylate groups than amino group), and lysine (more amino groups than carboxylate group) have been performed. The stability constants for the new macrocycle and binary complexes of the amino acid with the macrocyclic ligand are reported. Binary complexes are formed in aqueous solution as a result of hydrogen bonding interaction and electrostatic attraction between the host and the guest. The binding Schemes for the recognition of amino acids are suggested. From the results, it seems that this new macrocyclic ligand is able to bind three different amino acids with selectivity in aqueous solution, and the strength of binding is of the order lysine <glycine <aspartic acid.