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PubMed2003

Biodegradable, thermosensitive implant for approximating cylindrical structures: a preliminary study.

A new invention, i.e., a biodegradable, thermosensitive hybrid gel composite in the form of a thin sheet, was used as an implant inside the rat and guinea pig to test its tissue reactions, degradation, and function as a bridging agent. Tissue tractions in subcutaneous tissue, in muscle, around a peripheral nerve, and around an artery were mild. Degradation made rapid progress, starting on the third day and completed in 2-3 weeks. The hybrid gel, when wrapped around the cut ends of a peripheral nerve or an artery, functioned well as a bridging tube. In the case of the cut nerve, regenerating fascicles crept through the tube which protected them from fibrosis. In the case of the cut artery, patency of flow was maintained, and arterial wall healing was complete in 2-3 weeks. The hybrid gel composite contracted at body temperature, thus holding well to body tissues. Its biodegradable and inert nature offers the potential for future use as a tissue wrap and bridging agent.

Absorbable Implants↗
PubMed2004

Modified distally based peroneal artery perforator flap for reconstruction of foot and ankle.

The distally based sural fasciocutaneous flap has been used widely for reconstruction of foot and ankle soft-tissue defects. Here we report on a series of cases of foot and ankle reconstruction with a modified distally based sural flap. The vascular pedicle of the flap includes an axial perforator branch of the peroneal artery and two concomitant veins. This modified distally based perforator flap, measuring around 17 x 6 cm to 30 x 10 cm in size, was transferred for coverage of foot and ankle soft-tissue defects in 7 cases. All flaps survived completely. Neither arterial ischemia nor venous congestion was noted. As compared to other distally based sural flaps with neuro-veno-adipo-fascial pedicles, this modified sural flap with a thin perforator pedicle is easily rotated. The flap can obtain abundant blood supply through both axial perforator and longitudinal chain-linked vascular plexuses, and does not have the venous reflow problem. In conclusion, the invention of this perforator fasciocutaneous flap provides a valuable tool for repair of foot and ankle soft-tissue defects.

Accidents, Traffic↗
PubMed2005

Functional foods: planning and development.

The discussion on functional foods among scientific communities and EC commissions is mainly focused on definitions and on legislative issues related to the presence on the market of this kind of products. Although many new products continuously appear, the functional food market is characterized by a high rate of failure. To realize a successful functional food, experts having different background should work together following a detailed workplan. In this paper, the problems related to planning and development of functional foods are considered using a step-by-step approach. The strategies for invention and development, formulation and validation of nutritional claims are regarded also illustrating practical examples of functional food development. The concept of food for special medical purposes, intended for individuals who are being treated under medical supervision, is also introduced.

Chemical Phenomena↗
PubMed1992

Stein and Moore Award address. Reconstructing history with amino acid sequences.

The main goal of the protein evolutionist is the reconstruction of past events leading to the structures of contemporary proteins. The common strategy is to align amino acid sequences and make inferences about matters of common ancestry. The rate of change of amino acid sequence varies greatly from protein to protein, and this naturally affects how far back a given protein's ancestry can be traced. Happily, the rate of change of many proteins is slow enough that very ancient events can be inferred. Many mainstream metabolic enzymes, for example, are 40-50% identical in prokaryotes and eukaryotes, groups that diverged from a common ancestor more than 1.5 billion years ago. Moreover, some eukaryotic proteins like actin and tubulin change so slowly that they are seldom less than 60% identical, no matter from what source they are drawn. As it happens, prokaryotic counterparts for many eukaryotic cytoskeletal proteins are unknown. A recent exception involves the finding that a heat shock protein cognate is a relative of actin. The gene duplication that gave rise to these two proteins must have been an ancient event. The more recent invention of other proteins whose distribution is restricted to one or the other of the major kingdoms may be easier to trace. Among the factors that can confound the reconstruction of events, however, are occasional horizontal gene transfers and exon shuffling. The latter has led to a number of mosaic proteins, many of which contain various combinations of a relatively small set of modules like the epidermal growth factor domain.

Actins↗
PubMed1992

Characterization, primary structure, and evolution of lamprey plasma albumin.

The most abundant protein found in blood plasma from the sea lamprey (Petromyzon marinus) has the hallmarks of a plasma albumin: namely, high abundance, solubility in distilled water, a small number of tryptophans, and a high content of cysteines and charged residues. As in other vertebrate albumins, not all the cysteines are disulfide bonded. An unusual feature of this protein is its molecular weight of 175,000, roughly 2.5 times the size of other vertebrate albumins. Its amino acid sequence, deduced from a series of overlapping cDNA clones, can be aligned with other members of the gene family including plasma albumin, alpha-fetoprotein, and vitamin-D binding protein, confirming that it is indeed an oversized albumin. An unusual feature of the sequence is a 28-amino acid stretch consisting of a serine-threonine repeat with the general motif (STTT). Lamprey albumin contains a 23-amino acid putative signal peptide and a 6-residue putative propeptide, which, when cleaved, yield a mature protein of 1,394 amino acids with a calculated molecular weight of 157,000. The sequence also includes nine potential N-linked glycosylation sites (Asn-X-Ser/Thr), consistent with observation that lamprey albumin is a glycoprotein. If all the potential glycosylation sites were occupied by clusters of 2,000 molecular weight each, the total molecular weight would be 175,000. Like other members of the gene family, lamprey albumin is composed of a series of 190-amino acid repeats, there being seven such domains all together. Quantitative amino acid sequence comparisons of lamprey albumin with the other members of the gene family indicate that it diverged from an ancestral albumin prior to the gene duplications leading to this diverse group. This notion is confirmed by the pattern of amino acid insertions and deletions observed in a consideration of all domains that compose this family. Furthermore, it suggests that the invention of albumin antedates the vertebrate radiation.

Amino Acid Sequence↗
PubMed2002

The strobilurin fungicides.

Strobilurins are one of the most important classes of agricultural fungicide. Their invention was inspired by a group of fungicidally active natural products. The outstanding benefits they deliver are currently being utilised in a wide range of crops throughout the world. First launched in 1996, the strobilurins now include the world's biggest selling fungicide, azoxystrobin. By 2002 there will be six strobilurin active ingredients commercially available for agricultural use. This review describes in detail the properties of these active ingredients--their synthesis, biochemical mode of action, biokinetics, fungicidal activity, yield and quality benefits, resistance risk and human and environmental safety. It also describes the clear technical differences that exist between these active ingredients, particularly in the areas of fungicidal activity and biokinetics.

Agrochemicals↗
PubMed2003

Surface-activated no-discharge atmospheric pressure chemical ionization.

A new ionization method named surface-activated chemical ionization (SACI) has been realized. In this invention a commercially available atmospheric pressure chemical ionization (APCI) chamber, employed without any corona discharge (no-discharge APCI), has been modified with the insertion of a gold surface, leading to a significant improvement in the ionization efficiency. The ionization of the sample takes place by both gas-phase and surface-activated processes. This new ionization source is able to generate ions with high molecular mass and low charge states, leading to improved sensitivity and reduced noise. The new device has been tested in the analysis of some peptides. A comparison between the performance with and without the presence of the surface, and the optimization of the operating conditions (nebulizing gas flow, sample solution flow, pH of solution, and surface area), are reported and discussed.

Air Pressure↗
PubMedDate not supplied

Contact angle analysis on polymethylmethacrylate and commercial wax by using an environmental scanning electron microscope.

The environmental scanning electron microscope (ESEM) represents one of the most exciting breakthroughs in electron microscopy since the invention of the electron microscope. Its ability to observe uncoated and hydrated samples enhances the possibility for investigating the wettability of surfaces at a microscopic level; by varying the relative vapour pressure or the temperature inside the chamber, it is possible to condense water drops on a micron scale. A large problem in measuring contact angles by ESEM is that the observation angle is not parallel or perpendicular to the surface; thus, the study of the droplets profile using the common algorithms such as spherical approximation or axisymmetric drop shape analysis (ADSA) is not possible, because only a spherical cap shape is commonly observed. In this paper we provide a useful mathematical model to calculate the real contact angle from the initial images. Initially, some simulated spherical caps with different contact and observation angles were created by an appropriate graphic package in order to test the mathematical model. Some real drops obtained by ESEM on wax and polymethylmethacrylate (PMMA) were then studied and the results compared with contact angles measured by common methods on the same materials.

Journal Article↗
PubMed2006

Nanoscience of single polymer chains revealed by nanofishing.

The invention of atomic force microscopy (AFM) enabled us to study the statistical properties of single polymer chains by a method called "nanofishing," which stretches a single polymer chain adsorbed on a substrate with its one end by picking it at the other end. A force-extension curve obtained for a single polystyrene chain in a Theta solvent (cyclohexane) shows good agreement with a worm-like chain model and, therefore, gives microscopic information about entropic elasticity. Furthermore, the nanofishing technique can be used for dynamic viscoelastic measurement of single polymer chains. An AFM cantilever is mechanically oscillated at its resonant frequency during the stretching process. This technique enables the estimation of quantitative and simultaneous elongation-dependent changes of stiffness and viscosity of a single chain with the use of a phenomenological model. In this study, the effect of solvent on viscosity in low extension regions reveals that the viscosity is attributed to monomer-solvent friction. Thus, static and dynamic nanofishing techniques are shown to give powerful experimental proofs for several basic questions in polymer physics. The techniques are expected to reveal hidden properties of polymer chains or polymer solutions by any types of macroscopic measurements in the future.

Journal Article↗
PubMed1996

Upside-down stopped-flow electrofractionation of complex protein mixtures.

The excellent resolution of SDS-PAGE in protein analysis stimulated the creation of various preparative devices. The main approach used in these devices is the construction of a elution chamber in the lower end of the polyacrylamide gel cylinder or plate. Although this continuous lower buffer flow electrofractionation system serves as an acceptable preparative electrophoresis, some limitations to this approach exist. There is strong dilution of protein zones by the eluting buffer, which drastically restricts the sensitivity of the determination of minor proteins, and the restricted current flow caused by electric resistance arising from the column holder prevents application to purification of complex protein mixtures. To overcome these problems, the upside-down stopped-flow electrofractionation system (UDSFE) was designed. The necessary quantity of fraction is drawn with a pipet in a small volume from just above the gel cylinder. This invention improves the possibility of electrofractionation of deluted complex protein mixtures. The efficiency of this technique is demonstrated by purification a protein kinase from rat liver. The method has also been successfully used for purification of error-correcting 3'-5' exonuclease.

Animals↗
PubMed2000

The different roles of social learning in vocal communication.

While vocal learning has been studied extensively in birds and mammals, little effort has been made to define what exactly constitutes vocal learning and to classify the forms that it may take. We present such a theoretical framework for the study of social learning in vocal communication. We define different forms of social learning that affect communication and discuss the required methodology to show each one. We distinguish between contextual and production learning in animal communication. Contextual learning affects the behavioural context or serial position of a signal. It can affect both usage and comprehension. Production learning refers to instances where the signals themselves are modified in form as a result of experience with those of other individuals. Vocal learning is defined as production learning in the vocal domain. It can affect one or more of three systems: the respiratory, phonatory and filter systems. Each involves a different level of control over the sound production apparatus. We hypothesize that contextual learning and respiratory production learning preceded the evolution of phonatory and filter production learning. Each form of learning potentially increases the complexity of a communication system. We also found that unexpected genetic or environmental factors can have considerable effects on vocal behaviour in birds and mammals and are often more likely to cause changes or differences in vocalizations than investigators may assume. Finally, we discuss how production learning is used in innovation and invention, and present important future research questions. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed2001

Sensory, digestive and metabolic influences on preference and intake.

In the 1960s. scientific work on the mechanisms of appetite began to shift from the effects of deprivation on reinforcement, motivation and sensation (hunger and thirst) to the influences of ingestion itself on what and how much was chosen at a bout of eating and drinking (the sating of appetite). This personal overview starts with John D. Davis's involvement in this trend to studying sensory, digestive and metabolic controls of meal volume, as he and the author each joined the field. The main topic is the diverse series of innovative experiments that Davis carried out in the author's research group in 1970 1971. This work exemplified Davis's technical inventiveness and theoretical precision. It generated influential findings on behavioural roles of dietary flavours, gastric distension and hepatic metabolism.

Animals↗
PubMed1994

Two cases of deep dyslexia in unilingual hispanophone aphasics.

This paper addresses the interaction between a particular cognitive property inherent to the human brain, i.e., the capacity to learn how to process written information in a manner such that reading words aloud can become a standard aspect of overt behavior, and some of the culture-linked characteristics of the written codes invented by the species. First, the paper reiterates that the Spanish written code is transparent to the point of entailing full graphophonemic conversion, i.e., reading behavior is possible without access to one's memory of written words (to one's "logographic lexicon"). The Ardila claim (Ardila, 1991; Ardila, Rosselli, & Pinzon, 1989) that certain clinical forms of acquired reading disorders which have been reported to occur among various cultural subgroups do not occur among unilingual readers of Spanish is then summarized. This is followed by two brief case reports of acquired aphasia in native speakers and fluent readers of Spanish; prototypical "deep dyslexia" was documented to exist in both cases (Ruiz & Ansaldo, 1990). The Ardila claim is thereafter assessed by reference to the notions of surface, phonological, and deep dyslexia; parameters such as educational background are taken into account in this discussion.

Aphasia↗
PubMed2000

Individual- and population-based diversity in restriction-modification systems.

Restriction-modification (RM) systems are cognate gene complexes that code for an endonuclease and a methylase. They are often thought to have developed in bacteria as protection against invading genetic material, e.g., phage DNA. The high diversity of RM systems, as observed in nature, is often ascribed to the coevolution of RM systems (which 'invent' novel types) and phages. However, the extent to which phages are insensitive to RM systems casts doubts on the effectiveness of RM systems as protection against infection and thereby on the reason for the diversity of RM systems. We present an eco-evolutionary model in order to study the evolution of the diversity of RM systems. The model predicts that in general diversity of RM systems is high. More importantly, the diversity of the RM systems is expressed either at the individual level or at the population level. In the first case all individuals carry RM systems of all sequence specificities, whereas in the second case they carry only one RM system or no RM systems at all. Nevertheless, in the second case the same number of sequence specificities are present in the population.

Bacteria↗
PubMed2002

Libet's temporal anomalies: a reassessment of the data.

Benjamin Libet compared the perceived time of direct brain stimulation to the perceived time of skin stimulation. His results are among the most controversial experiments at the interface between psychology and philosophy. The new element that I bring to this discussion is a reanalysis of Libet's raw data. Libet's original data were difficult to interpret because of the manner in which they were presented in tables. Plotting the data as psychometric functions shows that the observers have great uncertainty about the relative timing of events, as seen the shallow psychometric slopes. A second indication of uncertainty comes from Libet's use of three response categories, A first; B first; and A and B simultaneous. The large number of "perceptually simultaneous" responses provides a further measure of the difficulty of the judgment. There are thus a very broad range of stimulus delays in which the subject is unable to make an accurate ordering response. These points provide evidence that there is no compelling reason to invent exotic or ad hoc mechanisms to account for Libet's data since the uncertainty window is large enough to allow simple mechanism such as memory shifts. Libet argued that his data provide evidence for a backward referral in time. I argue that even though Libet's own data are weak, there are good arguments for a backward referral mechanism to help the subject make sense out of the tangled chaos of asynchronous information associated with experienced events.

Cerebral Cortex↗
PubMed1997

Engineering-Based Contributions in Cryobiology

Over the past three decades there has been an increasing number of engineering-trained researchers who have made the field of cryobiology a primary focus of their work. In prior times the advances in cryobiology were accomplished nearly exclusively by members of the life and medical science communities. In general, the practice of engineering may be distinguished by two features: an emphasis on rigorous quantitative measurement and analysis of processes and the synthesis of an understanding of fundamental principles of nature into the design of novel devices and processes for specific applications. One area of focus in cryobiology that engineers have emphasized is the design of new apparatus, including both experimental instrumentation and clinical diagnostic and therapeutic devices. There has been a broad spectrum of new apparatus invented to enable the quantitative control and measurement of the fundamental phenomena that govern processes in cryobiology. Among these are low-temperature cryomicroscopy stages and mass diffusion chambers, which now are often used in conjunction with digital image analysis algorithms to quantify changes to individual cells and tissues elicited during the process being studied. Other applications include the development of novel measurement techniques for assessing system properties and states during freezing and thawing. In cryosurgery and in cryopreservation new probes and apparatus have been designed to provide more accurate and effective processes to achieve clinical objectives. Equally important and complementary to the design of hardware is the development of analytical models which can be applied to understand and interpret experimental data and to predict the behavior of systems for operation in domains beyond those for which empirical data are available. Perhaps the most critical role of these models is for inverse solution techniques with experimental data to obtain values for the intrinsic constitutive properties of tissues which govern their response to freezing and thawing processes.

Journal Article↗
PubMed2002

Conservation of Brachyury, Mef2, and Snail in the myogenic lineage of jellyfish: a connection to the mesoderm of bilateria.

One major difference between simple metazoans such as cnidarians and all the bilaterian animals is thought to involve the invention of mesoderm. The terms diploblasts and triploblasts are therefore, often used to group prebilaterian and bilaterian animals, respectively. However, jellyfish contain well developed striated and smooth muscle tissues that derive from the entocodon, a mesoderm-like tissue formed during medusa development. We investigated the hypothesis, that the entocodon could be homologous to the third germ layer of bilaterians by analyzing the structures and expression patterns of the homologues of Brachyury, Mef2, and Snail in the jellyfish Podocoryne carnea. These are regulatory genes from the T-box, MADS-box and zinc finger families known to play important roles in bilaterian mesoderm patterning and muscle differentiation. The sequence and expression data demonstrate that the genes are structurally and functionally conserved and even more similar to humans or other deuterostomes than to protostome model organisms such as Drosophila or Caenorhabditis elegans. Based on these data we conclude that the common ancestor of the cnidarians and bilaterians not only shared genes that play a role in regulating myogenesis but already used them to develop and differentiate muscle systems similar to those of triploblasts.

Animals↗
PubMed1997

Imaginary companions in adolescence: sign of a deficient or positive development.

The present study was designed to find out to what extent imaginary companions are created in the diaries of adolescents. A total of 241 adolescents aged 12 to 17 years were investigated to determine the incidence as well as the characteristics and functions of such fictitious individuals in this age group. Content analysis of data obtained from questionnaires revealed that the imaginary companion was similar to the writer in many aspects. The imaginary companion supported the adolescent during the process of developing his/her identity. The relative influence of self-concept, creativity, role-taking ability, coping behavior, and egocentrism was then investigated using a hierarchical regression model. Three hypotheses were tested: (1) the deficit hypothesis, i.e. only adolescents with a deficit in social interaction create an imaginary companion, (2) the giftedness hypothesis, i.e. especially creative adolescents invent such a companion and (3) the egocentrism hypothesis, i.e. the construction of an imaginary companion is the result of perceived uniqueness and related to personal fable and imaginary audience behaviour. The results showed that the imaginary companion was not the result of an egocentric orientation, and by no means was a substitute for other trustworthy partners such as family members or friends. On the contrary, socially competent and creative adolescents with good coping abilities were particularly prone to create such a "very special friend".

Adaptation, Psychological↗