Silicon micromachined hollow microneedles for transdermal liquid transfer

This paper presents an improved design and fabrication process [ 13 for hollow micro needles with the proper mechanical strength and sharpness to be applied for painless transdermal transfer of liquids. Tests have shown that liquids like blood are drawn into the needle by capillary forces, reducing the need for active pumping. The fabrication method allows different needle shapes like blades and pencils, is robust enough to be applied for largerscale production, and enables the development of a complete micro-TAS for e.g. blood analysis

Strong Ramsey games: Drawing on an infinite board

Consider the following strong Ramsey game. Two players take turns in claiming a previously unclaimed edge of the complete graph on n vertices until all edges have been claimed. The first player to build a copy of K5 is declared the winner of the game. If none of the players win, then the game ends in a draw. A simple strategy stealing argument shows that the second player cannot expect to ever win this game. Moreover, for sufficiently large n, it follows from Ramsey’s Theorem that the game cannot end in a draw and is thus a first player win. A famous question of Beck asks whether the minimum number of moves needed for the first player to win this game on Kn grows with n. This seems unlikely but is still wide open. A striking equivalent formulation of this question is whether the same game played on the infinite complete graph is a first player win or a draw. The target graph of the strong Ramsey game does not have to be K5, it can be any predetermined fixed graph. In fact, it can even be a k-uniform hypergraph (and then the game is played on the infinite k-uniform hypergraph). Since strategy stealing and Ramsey’s Theorem still apply, one can ask the same question: is this game a first player win or a draw? The same intuition which lead most people (including the authors) to believe that the K5 strong Ramsey game on the infinite board is a first player win, would also lead one to believe that the H strong Ramsey game on the infinite board is a first player win for any uniform hypergraph H. However, in this paper we construct a 5-uniform hypergraph for which the corresponding game is a draw

Variation in the level of aggression, chemical and genetic distance among three supercolonies of the Argentine ant in Europe.

In their invasive ranges, Argentine ant populations often form one geographically vast supercolony, genetically and chemically uniform within which there is no intraspecific aggression. Here we present regional patterns of intraspecific aggression, cuticular hydrocarbons (CHCs) and population genetics of 18 nesting sites across Corsica and the French mainland. Aggression tests confirm the presence of a third European supercolony, the Corsican supercolony, which exhibits moderate to high levels of aggression, depending on nesting sites, with the Main supercolony, and invariably high levels of aggression with the Catalonian supercolony. The chemical analyses corroborated the behavioural data, with workers of the Corsican supercolony showing moderate differences in CHCs compared to workers of the European Main supercolony and strong differences compared to workers of the Catalonian supercolony. Interestingly, there were also clear genetic differences between workers of the Catalonian supercolony and the two other supercolonies at both nuclear and mitochondrial markers, but only very weak genetic differentiation between nesting sites of the Corsican and Main supercolonies (F(ST) = 0.06). A detailed comparison of the genetic composition of supercolonies also revealed that, if one of the last two supercolonies derived from the other, it is the Main supercolony that derived from the Corsican supercolony rather than the reverse. Overall, these findings highlight the importance of conducting more qualitative and quantitative analyses of the level of aggression between supercolonies, which has to be correlated with genetic and chemical data

Is the postpharyngeal gland of a solitary digger wasp homologous to ants? Evidence from chemistry and physiology

The postpharyngeal gland (PPG) was thought to be restricted to ants where it serves a crucial function in the generation of the colony odour. Recently, head glands that closely resemble the PPG of ants were discovered in females of a solitary digger wasp, the European beewolf. The function of this gland necessarily differs from ants: beewolf females apply the secretion of their PPG onto the bodies of paralysed honeybees that serve as larval provisions in order to delay fungus growth. Since ants and digger wasps are not closely related, the occurrence of this gland in these two taxa might either be due to convergent evolution or it is a homologous organ inherited from a common ancestor. Here we test the hypothesis that the PPGs of both taxa are homologous by comparing characteristics of chemical composition and physiology of the PPG of beewolves and ants. Based on reported characteristics of the PPG content of ants, we tested three predictions that were all met. First, the PPG of beewolves contained mainly long-chain hydrocarbons and very few compounds with functional groups. Second, the composition of hydrocarbons in the beewolf PPG was similar to that of the hemolymph. Taking the structure of the gland epithelium and the huge requirements of beewolf females for gland secretion into account this result suggests that the content of the PPG is also sequestered from the hemolymph in beewolves. Third, the chemical composition of the PPG and the cuticle was similar in beewolves since cuticular hydrocarbons derive either from the hemolymph or the PPG. Taking the considerable morphological similarities into account, our results support the hypothesis of a homologous origin of the PPG in beewolves and ants

Strong Ramsey games: drawing on an infinite board

We consider the strong Ramsey-type game R(k)(H,ℵ0), played on the edge set of the infinite complete k-uniform hypergraph KkN. Two players, called FP (the first player) and SP (the second player), take turns claiming edges of K^k_N with the goal of building a copy of some finite predetermined k-uniform hypergraph H. The first player to build a copy of H wins. If no player has a strategy to ensure his win in finitely many moves, then the game is declared a draw. In this paper, we construct a 5-uniform hypergraph H such that R(5)(H,ℵ0) is a draw. This is in stark contrast to the corresponding finite game R(5)(H,n), played on the edge set of K5n. Indeed, using a classical game-theoretic argument known as \emph{strategy stealing} and a Ramsey-type argument, one can show that for every k-uniform hypergraph G, there exists an integer n0 such that FP has a winning strategy for R(k)(G,n) for every n≥n0

Ultrastructure of the Intramandibular Gland of Workers and Queens of the Stingless Bee, Melipona quadrifasciata

The intramandibular glands of workers and queens of Melipona quadrifasciata Lepeletier (Hymenoptera: Apidae), at different ages and from different functional groups, were studied using light and transmission electron microscopy. The results demonstrated that these glands are composed of two types of secretory structures: 1.A hypertrophied epidermis on the dorsal side of the mandible that is an epithelial gland. 2. Free secretory cells filling the inner spaces of the appendices that constitute a unicellular gland. The epithelial gland is larger in the young (1-2-day-old workers), and the gland becomes involuted during the nurse worker stage. The unicellular glands of the workers posses some secretion during all of the studied phases, but secretory activity is more intensive in the foraging workers. Vesicles of secretion are absent in the unicellular glands of queens. These results demonstrate that these glands show functional adaptations in different castes corresponding to the functions of each caste

The Chemistry of the Postpharyngeal Gland of Female European Beewolves

Females of the European beewolf, Philanthus triangulum, possess a large glove-shaped gland in the head, the postpharyngeal gland (PPG). They apply the content of the PPG to their prey, paralyzed honeybees, where it delays fungal infestation. Here, we describe the chemical composition of the gland by using combined GC-MS, GC-FTIR, and derivatization. The PPG of beewolves contains mainly long-chain unsaturated hydrocarbons (C23–C33), lower amounts of saturated hydrocarbons (C14–C33), and minor amounts of methyl-branched hydrocarbons (C17–C31). Additionally, the hexane-soluble gland content is comprised of small amounts of an unsaturated C25 alcohol, an unknown sesquiterpene, an octadecenylmethylester, and several long-chain saturated (C25, C27) and unsaturated (C23–C27) ketones, some of which have not yet been reported as natural products. Surprisingly, we found a dimorphism with regard to the major component of the PPG with some females having (Z)-9-pentacosene, whereas others have (Z)-9-heptacosene as their predominant component. The biological relevance of the compounds for the prevention of fungal growth on the prey and the significance of the chemical dimorphism are discussed

Searching for gravitational waves from known pulsars

We present upper limits on the amplitude of gravitational waves from 28 isolated pulsars using data from the second science run of LIGO. The results are also expressed as a constraint on the pulsars' equatorial ellipticities. We discuss a new way of presenting such ellipticity upper limits that takes account of the uncertainties of the pulsar moment of inertia. We also extend our previous method to search for known pulsars in binary systems, of which there are about 80 in the sensitive frequency range of LIGO and GEO 600.Comment: Accepted by CQG for the proceeding of GWDAW9, 7 pages, 2 figure

Detector Description and Performance for the First Coincidence Observations between LIGO and GEO

For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial change

Setting upper limits on the strength of periodic gravitational waves from PSR J1939+2134 using the first science data from the GEO 600 and LIGO detectors

Data collected by the GEO 600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsar's gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsar's equatorial ellipticity