Orthopedic implant used as drug delivery system: clinical situation and state of the research.

A partial review is proposed on the existing literature for the research performed in orthopedic implant used as drug delivery system. In the first part, an evaluation is given on the clinical need to deliver a drug in the surrounding of an implant. Secondly, a review of the clinical situation is developed for implants already used as drug delivery system. Experimental works performed for local delivery are reported. In particular, a description is given on the in vitro and in vivo studies where the implant is coated with different proteins or drugs. Finally, a conclusion is proposed on the next step in the development of orthopedic implant as drug delivery system mentioning also the industrial situation.

Putting the Special Case in Its Place: Switzerland and Small-N Comparison in Policy Research

This research note presents a set of strategies to conduct small-N comparisons in policy research including the Swiss case. Even though every country can be considered "special" to some extent, the Swiss political system is often viewed as a particularly difficult case for comparison because of the impact of its idiosyncratic institutional features (most notably direct democracy). In order to deal with this problem, our note sets out two possible strategies - the use of functional equivalents and of counterfactual reasoning - and explains how to implement them empirically through process tracing and the establishment of causal chains. As an illustration, these strategies are used for a comparison of the process of electricity market liberalisation in Switzerland and Belgium.

Institutional landmarks in Brazilian research on soil erosion: a historical overview

The problem of soil erosion in Brazil has been a focus of agricultural scientific research since the 19th century. The aim of this study was to provide a historical overview of the institutional landmarks which gave rise to the first studies in soil erosion and established the foundations of agricultural research in Brazil. The 19th century and beginning of the 20th century saw the founding of a series of institutions in Brazil, such as Botanical Gardens, executive institutions, research institutes, experimental stations, educational institutions of agricultural sciences, as well as the creation and diversification of scientific journals. These entities, each in its own way, served to foster soil erosion research in Brazil. During the Imperial period (1808-1889), discussions focused on soil degradation and conserving the fertility of agricultural land. During the First Republic (1889-1930), with the founding of various educational institutions and consolidation of research on soil degradation conducted by the Agronomic Institute of Campinas in the State of São Paulo, studies focused on soil depletion, identification of the major factors causing soil erosion and the measures necessary to control it. During the New State period (1930-1945), many soil conservation practices were developed and disseminated to combat erosion and field trials were set up, mainly to measure soil and water losses induced by hydric erosion. During the Brazilian New Republic (1945-1964), experiments were conducted throughout Brazil, consolidating soil and water conservation as one of the main areas of Soil Science in Brazil. This was followed by scientific conferences on erosion and the institutionalization of post-graduate studies. During the Military Regime (1964-1985), many research and educational institutions were founded, experimental studies intensified, and coincidently, soil erosion reached alarming levels which led to the development of the no-tillage system.

Interlaboratory comparison of size measurements on nanoparticles using nanoparticle tracking analysis (NTA)

One of the key challenges in the field of nanoparticle (NP) analysis is in producing reliable and reproducible characterisation data for nanomaterials. This study looks at the reproducibility using a relatively new, but rapidly adopted, technique, Nanoparticle Tracking Analysis (NTA) on a range of particle sizes and materials in several different media. It describes the protocol development and presents both the data and analysis of results obtained from 12 laboratories, mostly based in Europe, who are primarily QualityNano members. QualityNano is an EU FP7 funded Research Infrastructure that integrates 28 European analytical and experimental facilities in nanotechnology, medicine and natural sciences with the goal of developing and implementing best practice and quality in all aspects of nanosafety assessment. This study looks at both the development of the protocol and how this leads to highly reproducible results amongst participants. In this study, the parameter being measured is the modal particle size.

Oxygen content and inhomogeneity effects on the electrical properties of YBa2Cu3Oy thin films

Oxygen content is a very important factor influencing the electrical properties of YBa2Cu3Oy. In this work the electrical properties of laser deposited YBa2Cu3Oy thin films on LaAlO3(100), in the whole range 6 y 7, are studied. An electrical network model, which randomly assigns oxygen contents and R(T) characteristics to the different elements in the circuit according to an arbitrary distribution, is used to analyze several features in the measured R(T) characteristics as a function of oxygen homogeneity. The model takes into account both short-range and long-range oxygen inhomogeneities. Good agreement between estimated oxygen contents from x-ray diffraction data in our samples and the average oxygen contents used to reproduce their R(T) characteristics is found. The model points out that oxygen homogeneity is very important in order to get the best and reproducible properties, and for conduction and superconductivity analysis through the shape or derivatives of R(T) characteristics.

Looming Scarcity of Phosphate Rock and Intensification of Soil Phosphorus Research

In recent years, many researchers have claimed that world reserves of rock phosphate were getting depleted at an alarming rate, putting us on the path to scarcity of that essential resource within the next few decades. Others have claimed that such alarmist forecasts were frequent in the past and have always been proven unfounded, making it likely that the same will be true in the future. Both viewpoints are directly relevant to the level of funding devoted to research on the use of phosphate fertilizers. In this short essay, it is argued that information about future reserves of P or any other resource are impossible to predict, and therefore that the threat of a possible depletion of P reserves should not be used as a key motivation for an intensification of research on soil P. However, there are other, more compelling reasons, both geopolitical and environmental, to urgently step up our collective efforts to devise agricultural practices that make better use of P than is the case at the moment.

BEYOND THE “LEAST LIMITING WATER RANGE”: RETHINKING SOIL PHYSICS RESEARCH IN BRAZIL

As opposed to objective definitions in soil physics, the subjective term “soil physical quality” is increasingly found in publications in the soil physics area. A supposed indicator of soil physical quality that has been the focus of attention, especially in the Brazilian literature, is the Least Limiting Water Range (RLL), translated in Portuguese as "Intervalo Hídrico Ótimo" or IHO. In this paper the four limiting water contents that define RLLare discussed in the light of objectively determinable soil physical properties, pointing to inconsistencies in the RLLdefinition and calculation. It also discusses the interpretation of RLL as an indicator of crop productivity or soil physical quality, showing its inability to consider common phenological and pedological boundary conditions. It is shown that so-called “critical densities” found by the RLL through a commonly applied calculation method are questionable. Considering the availability of robust models for agronomy, ecology, hydrology, meteorology and other related areas, the attractiveness of RLL as an indicator to Brazilian soil physicists is not related to its (never proven) effectiveness, but rather to the simplicity with which it is dealt. Determining the respective limiting contents in a simplified manner, relegating the study or concern on the actual functioning of the system to a lower priority, goes against scientific construction and systemic understanding. This study suggests a realignment of the research in soil physics in Brazil with scientific precepts, towards mechanistic soil physics, to replace the currently predominant search for empirical correlations below the state of the art of soil physics.