Controlling Internal Pore Sizes in Bicontinuous Polymeric Nanospheres

Complex polymeric nanospheres were formed in water from comb-like amphiphilic block copolymers. Their internal morphology was determined by three-dimensional cryo-electron tomographic analysis. Varying the polymer molecular weight (MW) and the hydrophilic block weight content allowed for fine control over the internal structure. Construction of a partial phase diagram allowed us to determine the criteria for the formation of bicontinuous polymer nanosphere (BPN), namely for copolymers with MW of up to 17?kDa and hydrophilic weight fractions of ?0.25; and varying the organic solvent to water ratio used in their preparation allowed for control over nanosphere diameters from 70 to 460?nm. Significantly, altering the block copolymer hydrophilic–hydrophobic balance enabled control of the internal pore diameter of the BPNs from 10 to 19?nm

Giant slip lengths of a simple fluid at vibrating solid interfaces

It has been shown recently [PRL 102, 254503 (2009)] that in the plane-plane configuration a mechanical resonator vibrating close to a rigid wall in a simple fluid can be overdamped to a frozen regime. Here, by solving analytically the Navier Stokes equations with partial slip boundary conditions at the solid fluid interface, we develop a theoretical approach justifying and extending these earlier findings. We show in particular that in the perfect slip regime the above mentioned results are, in the plane-plane configuration, very general and robust with respect to lever geometry considerations. We compare the results with those obtained previously for the sphere moving perpendicularly and close to a plane in a simple fluid and discuss in more details the differences concerning the dependence of the friction forces with the gap distance separating the moving object (i.e., plane or sphere) from the fixed plane. Finally, we show that the submicron fluidic effect reported in the reference above, and discussed further in the present work, can have dramatic implications in the design of nano-electromechanical systems (NEMS).Comment: submitted to PRE (see also PRL 102, 254503 (2009)

Effective algebraic degeneracy

We prove that any nonconstant entire holomorphic curve from the complex line C into a projective algebraic hypersurface X = X^n in P^{n+1}(C) of arbitrary dimension n (at least 2) must be algebraically degenerate provided X is generic if its degree d = deg(X) satisfies the effective lower bound: d larger than or equal to n^{{(n+1)}^{n+5}}

D 5.5.1.1. Final report on sensory testing in Africa for Group 1. Project AFTER “African Food Tradition rEvisited by Research”

This deliverable concerns the sensory evaluation of the reengineered group 1 African products in the AFTER project. Specifically, it related to reengineered akpan and gowe from Benin, kenkey from Ghana and Kishk Sa'eedi in Egypt. Concerning reengineered akpan from Benin, the sensory evaluation was undertaken in Montpellier, France. Re-engineering of akpan has focused primarily on improvement of sanitary properties of the product, which was a great achievement and will allow producing Akpan on a larger scale in SMEs in Africa. Sensory evaluation of the Akpan products was carried out using CATA and JAR techniques that have been developed for use with consumers instead of a trained panel. Three Akpan products were tested by 102 consumers: Akpan added with 10% sugar (AS10), Akpan added with 3% spray-dried milk and 8.7% sugar (AMS8.7) and Akpan added with 3% spray-dried milk and 15% sugar (AMS15). Independently of the Akpan tasted, Acidity or Sweetness attributes were scored “Just About Right, as I like” by 56 to 77% of consumers. Odour perception was perceived differently, depending on consumers. However, Texture was found “Too weak”, too liquid by the majority of consumers (49 to 55%) and Taste “too strong” (46 to 54%). The most frequently CATA descriptors checked by consumers which better described Akpan products were: “Artificial”, “Floral”, “New/Different”, “Strong in Taste”, “Mealy”, followed by “Liquid”, “Drinking yoghurt”, “Sweet”, “Acidic”, and “Rough”. At the opposite, an ideal-yoghurt was described as Creamy, Natural, Good for health, Refreshing, Homogeneous, with a texture of a Bulgarian yoghurt-type, Thick, Sweet, Attractive, Nutritious and Milk taste. In terms of sensory evaluation, the three Akpan products did not significantly. If we remove the terms such as “artificial”, “strong in taste”, “floral” due to a manufacturing error (use of a few drops of citronella essential oil instead of citronella infusion as a traditional flavouring of Akpan in Benin), it remains the terms “mealy”, “liquid” “drinking yoghurt” that better describe the product and were previously used for describing traditional Akpan product. This suggests that sensory properties of the reengineered Akpan may not be acceptable to French consumers who prefer a product with a creamy, homogeneous, Bulgarian yoghurt-type taste. Gowe in Benin was not tested using sensory evaluation. Sensory testing of Gowe in Benin was not undertaken because this was planned to be undertaken in Europe. The reason is because the methodology used in sensory evaluation is independent of the location provided the samples are the same. However, the particular samples provided for French sensory testing contained a concentration of aflatoxin that was higher than the minimum EU allowable limit. It was not possible to repeat the sensory test in France because it would have taken too long to obtain a replacement supply from Benin and to repeat the processing (takes one week). In which case the samples would have been took different to enable a comparison. The sensory evaluation of kenkey was carried at the Food Research Institute, Ghana. Current trends in urbanization, and the increasing popularity of kenkey among consumers, require larger scale production with consistent quality. Testing was conducted to determine the sensory profile of white reengineered kenkey made using the optimum pre-process conditions of steeping time (30 and 45h), steeping temperature (30ᵒC and 35ᵒC) and dough fermentation time of 12 hours. The qualitative descriptive analysis showed that the sensory profile of white kenkey was dependent on preprocessing variables. Thus merely optimizing the pre-processing variables with regards to acid production and other readily measurable constituents though could shorten the production process could not guarantee the best product sensory quality. The results show that all the descriptors generated were appropriate for differentiating sensory qualities among samples and could be used for basic research and product development for white kenkey. Soft and sticky texture in white kenkey was highly appreciated. Sensory evaluation of Kishk Sa'eedi (KS) was undertaken in Egypt. KS is an Egyptian indigenous wheat-based fermented food prepared traditionally according to the method applied by Upper Egyptians. This work is done to characterize sensory properties and sensory profile of the reengineered KS. Quantitative descriptive analysis (QDA) coupled with principal component analysis (PCA) was used to study the interrelationship among and between sensory attributes. 14 terms regarding appearance, odour, flavour and texture of the samples, was selected and a glossary describing each descriptor was developed. Three KS samples were profiled by 11 assessors using the chosen 14 sensory descriptors. Mean intensity ratings of the descriptive attributes showed that there were significant differences (p<0.05) within KS samples for all the 14 attributes tested. In general, high ratings for creamy colour, fresh odour, KS taste and fracturability are considered as positive effects that would be favoured by panellists while increase in caramel colour, sour taste, denseness and mouth coating are regarded as undesirable. The re-engineered KS sample perceived as less sour and less salty compared with the traditional ones. With regard to texture quality, reengineered sample was easy to fracture, and scored higher for grittiness. Meanwhile, the sample was rated lower than the traditional ones with regard to Kishk taste and fermented odour. Descriptive sensory evaluations between of the traditional and re-engineered KS samples showed that tastes i.e. sour, salty, and KS taste; fracutability and grittiness were discriminating attributes. Fermented odour, colour i.e. creamy and caramel; presence of fissure and presence of bran were least discriminating. Evaluation of the KS sensory characteristics provide in depth understanding of the sensory quality criteria as perceived by the sensory trained panel. The present study showed that substantial differences in sensory character were noted between the traditional and re-engineered KS in particular, differences in colour, fresh odour, KS taste, fracutability and mouth coating. This work showed that the application of QFD and PCA techniques could provide the useful information to KS and helped to identify the importance of product attributes. In conclusion the sensory evaluation showed clear sensory differences between the traditional and reengineered products relating to akpan from Benin, kenkey from Ghana and Kishk Sa'eedi from Egypt. Other deliverables will report on the acceptance by consumers

Tuning the metal-insulator transition in NdNiO3{\mathrm{NdNiO}}_{3} heterostructures via Fermi surface instability and spin fluctuations

We employed in situ pulsed laser deposition (PLD) and angle-resolved photoemission spectroscopy (ARPES) to investigate the mechanism of the metal-insulator transition (MIT) in NdNiO3 (NNO) thin films, grown on NdGaO3(110) and LaAlO3(100) substrates. In the metallic phase, we observe three-dimensional hole and electron Fermi surface (FS) pockets formed from strongly renormalized bands with well-defined quasiparticles. Upon cooling across the MIT in NNO/NGO sample, the quasiparticles lose coherence via a spectral weight transfer from near the Fermi level to localized states forming at higher binding energies. In the case of NNO/LAO, the bands are apparently shifted upward with an additional holelike pocket forming at the corner of the Brillouin zone. We find that the renormalization effects are strongly anisotropic and are stronger in NNO/NGO than NNO/LAO. Our study reveals that substrate-induced strain tunes the crystal field splitting, which changes the FS properties, nesting conditions, and spin-fluctuation strength, and thereby controls the MIT via the formation of an electronic order parameter with QAF∼(1/4,1/4,1/4±δ)

Proceedings of US - PRC international TOGA symposium

A series of 12 meridional transect along longitude 165°E in the Western Equatorial Pacific ocean were made between mid-1986 and mi-1988 : a time interval spanning an El Nino/Southern Oscillation (ENSO) event. Data collected on these cruises provide a detailed (albeit temporally sparse) view of the oceanic changes which occur in the Western Pacific during an ENSO event. The present work focuses on the evolution of the upper ocean thermohaline and zona velocity fields as revealed by high resolution hydrographic casts and direct near surface velocity measurements. (D'après résumé d'auteur

Rotation symmetry breaking in La2−xSrxCuO4{\mathrm{La}}_{2-x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4} revealed by angle-resolved photoemission spectroscopy

Using angle-resolved photoemission spectroscopy it is revealed that in the vicinity of optimal doping the electronic structure of La2−xSrxCuO4 cuprate undergoes an electronic reconstruction associated with a wave vector qa=(π,0). The reconstructed Fermi surface and folded band are distinct to the shadow bands observed in BSCCO cuprates and in underdoped La2−xSrxCuO4 with x≤0.12, which shift the primary band along the zone diagonal direction. Furthermore, the folded bands appear only with qa=(π,0) vector, but not with qb=(0,π). We demonstrate that the absence of qb reconstruction is not due to the matrix-element effects in the photoemission process, which indicates the fourfold symmetry is broken in the system

Code of conduct for scientific integrity

The scientific landscape has changed considerably since the Swiss Academies of Arts and Sciences published Integrity in scientific research: Principles and procedures in 2008. Consequently, an expert group was set up with members from the Swiss Academies of Arts and Sciences, the Swiss National Science Foundation, swissuniversities, and Innosuisse to review the changes that have taken place in recent years and to draw up this Code of conduct for scientific integrity. This Code is aimed at everyone involved in the generation, dissemination, and advancement of knowledge within the Swiss higher education system. This includes scientists, institutions, and funding organisations. Institutions and funding organisations have a special role to play in creating and maintaining the conditions in which scientific integrity can thrive. Scientific integrity is based on the observance of fundamental principles and their many different contextual concretisations. These principles guide scien- tists in their research and teaching and help them to deal with the practical, ethical, and intellectual challenges they can expect to encounter. The aim of this code of conduct is to promote appropriate attitudes and to help build a robust culture of scientific integrity that will stand the test of time. Ethical scientific behaviour rests on the basic principles of reliability, honesty, respect, and accountability and supports the concretisations of these basic principles within a specific frame of reference. This Code is intended to be a dynamic document. Its aim is to strengthen scientific integrity in all avenues of research and education, with a particular emphasis on the training and development of young people. Another of its aims is to establish a culture of research integrity in the scientific community, with the Code providing a welcome framework rather than imposing its own set of rules. It promotes common understanding and parity of treatment in dealing with violations of scientific integrity within and between institutions. The Code also considers current developments in the fields of Open Science and social media, and it examines the issue of time limitation from several points of view. In addition, it offers practical recommendations on how to set up an organisation for the protection of scientific integrity and describes the processes involved