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There is growing interest in developing methods to 'wrap' nano- and micron-sized biological objects within films that may offer protection, enhance their stability or improve performance. We describe the successful 'wrapping' of lectin-decorated microspheres, which serve as appealing model micron-sized objects, within cross-linked polymer film. This approach utilizes polymer chains able to undergo a structural metamorphosis, from being intramolecularly cross-linked to intermolecularly cross-linked, a process that is triggered by polymer concentration upon the particle surface. Experiments demonstrate that both complementary molecular recognition and the dynamic covalent nature of the crosslinker are required for successful 'wrapping' to occur. This work is significant as it suggests that nano- and micron-sized biological objects such as virus-like particles, bacteria or mammalian cells-all of which may benefit from additional environmental protection or stabilization in emerging applications-may also be 'wrapped' by this approach.

Fluorine-19 has high NMR detection sensitivity—similar to that of protons, owing to its large gyromagnetic ratio and high natural abundance (100%). Unlike protons, however, fluorine-19 (19F) has a negligible occurrence in biological objects, as well as a more sensitive chemical shift. As a result, in vivo 19F NMR spectroscopy and MR imaging offer advantages of negligible background signal and sensitive reporting of the local molecular environment. Here we report on NMR hyperpolarization of 19F nuclei using reversible exchange reactions with parahydrogen gas as the source of nuclear spin order. NMR signals of 3-fluoropyridine were enhanced by ~100 fold, corresponding to 0.3% 19F nuclear spin polarization (at 9.4 T) using ca. 50% parahydrogen. While future optimization efforts will likely significantly increase the hyperpolarization levels we already demonstrate the utility of 19F hyperpolarization for high-resolution hyperpolarized 19F imaging and hyperpolarized 19F pH sensing.

Stereofotografien lassen sich nach dem Anaglyphenprinzip mit rotem und grunem Halbbild relativ einfach herstellen. Die Stereoskopie ist in den Naturwissenschaften wertvoll, wenn anhand der zusatzlichen Tiefeninformation genauere Erkenntnisse zu Struktur und Form eines Objekts gewonnen werden konnen. Mittels verschiedener Motive aus Malakologie und Palaontologie sollen wesentliche Einsatzbereiche der Stereofotografie diskutiert werden. Fascination 3D-Photography: Stereo-photography of biological objects In this contribution a simple method for the production of stereophotographs according to the anaglyph principle with red and green stereo images is described. Additionally, the value of stereoscopy in natural sciences is presented. This is realized in all those fields, where additional spatial information provides enhanced knowledge on the structure and form of an object. By using various motifs from malacology and palaeontology the main areas of application of stereophotography will be discussed.

Janus particles are objects with two distinct domains of different surface chemistries that give them an amphiphilic character. The coexistence of hydrophilic and hydrophobic domains makes them suitable models for biological objects (e.g., proteins) and enables their use as “particle surfactants”. Since the time of their initial discovery, numerous strategies have been proposed for the realisation of Janus particles with variable and controlled size/functionality of the two surface domains. Owing to experimental limitations though, it has been rarely possible to ascertain and characterise the amphiphilic nature of the particles. We present here new results on the synthesis of spherical Janus microparticles with controlled surface chemistries and Janus ratios and on the measurement of their contact angle in situ at an oil–water interface, using freeze-fracture, shadow-casting cryo-scanning electron microscopy.

Electrospinning of nanofibers has developed quickly from a laboratory curiosity to a highly versatile method for the preparation of a wide variety of nanofibers, which are of interest from a fundamental as well as a technical point of view. A wide variety of materials has been processed into individual nanofibers or nanofiber mats with very different morphologies. The diverse properties of these nanofibers, based on different physical, chemical, or biological behavior, mean they are of interest for different applications ranging from filtration, antibacterial coatings, drug release formulations, tissue engineering, living membranes, sensors, and so on. A particular advantage of electrospinning is that numerous non-fiber forming materials can be immobilized by electrospinning in nanofiber nonwovens, even very sensitive biological objects such as virus, bacteria, and cells. The progress made during the last few years in the field of electrospinning is fascinating and is highlighted in this Feature Article, with particular emphasis on results obtained in the authors' research units. Specific areas of importance for the future of electrospinning, and which may open up novel applications, are also highlighted.

On the use of computer determinating methods in entomology. In this article the present situation of a computer-system for diagnostics of the systematical position of biological objects is examined. There different stages are shown, in which the research in this field of diagnostics have developed. In concrete examples of the list of scheme of destination for two groups of beatles the rules of preparation are shown how to inform the computer-systems and peculiarities of its working method are examined. It is reported about a Soviet system of such way, that is realized in a small computer. The importance of a computer-diagnosis for entomology is shown by it.

The distribution of magnetic microelds in systems with stochastic currents including plasmas, solids, and electrolytes is studied. It is shown that the random currents generate magnetic microelds distributed similar to the Holtsmark distribution for the electrical elds. Several relevant physical effects provided by this magnetic microeld and applications including plasma displays, microelectronic chips and currents in biological objects are discussed.

Form perception from coherent motion is an important aspect of vision. Representations of one-, two- and three-dimensional forms have been found at various stages of cortical processing using random-dot stimuli, whereas representations of biological objects like a walking human being concentrate at higher stages of processing. The perception of biological objects can be induced by sparse dot stimuli that consist of a few dots that mark the joints of the human body [G. Johansson (1973) Percept. Psychophys., 14, 201-211]. In the present study, we aimed to investigate whether neurons in early visual areas that respond to bars and edges defined by luminance contrast also signal bar-like objects from sparse dot stimuli. We studied single neurons with rows of 3-24 dots that were either collinear or scattered within a rectangular form. These dots were moved coherently on a uniform or dotted background, and human observers perceived them as rigid rods or other bar-like objects. We found neurons in the visual cortex of the awake, behaving monkey that responded to these stimuli and were sensitive to the orientation of these objects as for conventional bars or edges. Stimulus conditions that failed to induce these percepts in human observers also evoked weaker responses or none in these neurons. We found these neurons with increasing frequency in areas V1, V2 and V3/V3A. The results suggest that the visual cortex not only detects biological objects, but also lines and other bar-like objects from sparse dot stimuli, and that this function evolves at an early stage of processing.

The automation of palynology (the identification and counting of pollen grains and spores) will be a small step for image recognition, but a giant stride for palynology. Here we show the first successful automated identification, with 100% accuracy, of a realistic number of taxa. The technique used involves a neural network classifier applied to surface texture data from light micro- scope images. A further significance of the technique is that it could be adapted for the identification of a wide range of biological objects, both microscopic and macroscopic. Copyright 2004 John Wiley & Sons, Ltd.

A new combination of sample preparation, imaging and image processing techniques allowing new insights into the structure of biological objects has been developed as a method for the visualization and quality evaluation. This method is for the first time transferred to soybeans (Glycins soja L.) of the Nattousyoryu variety as an example of food and agricultural produce using volume rendering of thin slice microscopy images. By this method, soybeans are displayed as three-dimensional data representations for visualization. Internal structures like the dormant cotyledon leafs are visualized and highlighted. Une nouvelle combinaison de techniques de preparation, d'imagerie et de traitement de l'image permettant une vision nouvelle de la structure des objets biologiques est developpee en tant que methode pour la visualisation et l'evaluation de la qualite. Cette methode est appliquee pour la premiere fois au soja (Glycin soja L.) comme exemple de produit alimentaire et agricole en rendant la dimension de volume par des images microscopiques de fines tranches. L'imagerie en fluorescence est aussi utilisee.

Micro- and nanofabrication techniques have provided an unprecedented opportunity to create a designed world in which separation and fractionation technologies which normally occur on the macroscopic scale can be optimized by designing structures which utilize the basic physics of the process, or new processes can be realized by building structures which normally do not exist without external design. Since microfabrication is exceedingly sophisticated in its development, it is possible to design and construct highly creative microdevices which allow one to probe specific aspects of biological objects. We give examples of uses of micro- and nanofabrication which, as opposed to simply shrinking the size of the vessels or tubes used in macroscopic lab environments, utilize our understanding of the physics of the process to take advantage of fabrication technologies.

The field of electrochemical detection and sensing is briefly surveyed. Some general problems are pointed out, e.g., the limited reproducibility of the sensor surface, difficulties with the long-term stability of sensors, or slow response of many electrochemical devices. On the other hand, promises and opportunities for the future involve further sensor miniaturization, combination of sensing and detection with chemometric techniques and/or with other measuring techniques, potentialities of in vivo measurements in biological objects, or mass production of simple and low cost single-use sensors.

Self-cleaning methods currently employed are based on understanding of the functions, structures, and principles of various objects found in living nature. Three types of surfaces, including superhydrophobic, superoleophobic, and superhydrophilic, offer solutions to keep a surface clean. In this review article, an overview of self-cleaning surfaces inspired by nine biological objects is provided: lotus leaves, rice leaves, cicada wings, butterfly wings, snail shell, fish scale, shark skin, pitcher plant, and photosynthesis. These surfaces exhibit special properties such as low adhesion, low drag, anisotropic wetting, anti-reflection, directional adhesion, anti-fouling, photocatalysis, self-sterilizing, and anti-fogging. We discuss the differences between the superhydrophobic and superhydrophilic surfaces and perspectives for self-cleaning surfaces in the future.

SUMMARY Quantitative studies of three-dimensional (3-D) structure of microscopic objects have been made possible through the introduction of microscopic volume imaging techniques, most notably the confocal fluorescence microscope (CFM). Although the CFM is a true volume imager, its specific imaging properties give rise to distortions in the images and hamper subsequent quantitative analysis. Therefore, it is a prerequisite that confocal images are restored prior to analysis. The distortions can be divided into several categories: attenuation of areas in the image due to self-absorption, bleaching effects, geometrical effects and distortions due to diffraction effects. Of these, absorption and diffraction effects are the most important. This paper describes a method aimed at the correction of diffraction-induced distortions. All the steps necessary in restoring confocal images are discussed, including a novel method to measure instrumental properties on a routine basis. To test the restoration procedure an image of a fluorescent planar object was restored. The results show a considerable improvement in the z-resolution and no ringing artefacts. The relevance of the method for image analysis is demonstrated by a comparison of results of applying 3-D texture analysis to restored and unrestored images of a synthetic object. Furthermore, the method can be successfully applied to noisy fluorescence images of biological objects, such as interphase cell nucei.

Needle-type voltammetric ultramicroelectrodes show exceptional sensitivity for the detection of redox-active substances, rapid response times, and total tip diameters in the lower micrometer range. These characteristics make them ideal for analyzing the chemical environment and the activity of isolated living cells, which in their various forms are the microscopic building blocks of human, animal, and other life forms. Prerequisites for successful local electrochemical measurements in the vicinity of the tiny biological objects are gentle, stress-free, and accurate placement of the tip at the cell, exact knowledge of the tip-to-cell distance, and appropriate selectivity of the ultramicroelectrode tip for species that may change in concentration as a result of cellular actions such as growth, respiration, or transmitter and metabolite uptake or release. The concepts of single-cell microelectrochemistry are considered and an overview is given of recent results on the fundamental mechanisms of cell functions.

Atomic Force Microscopy becomes an invaluable technique for the study of biological systems at a nanometric scale [1, 2]. During the past decade, it has been increasingly used to image and manipulate biomolecules and cell surfaces in air or in situ. Development of dynamic modes of operation adapted for the imaging of soft samples has significantly contributed to overcome the usual issue of damage done to these biological objects by the scanning tip [3].

Progress in biological sciences asks for modeling tools that would allow simple communication of complex biological objects. According to electron microscopic studies, cells are packed with intracellular organelles that vary widely in size and shape and are in complex spatial relations to each other. We introduce here a modeling concept that allows building of complex structures such as muscle cells according to imagination of scholars.

Methods for determining the thermal measurements of biological objects have found ever increasing application in biology. This paper analyzes the temperature dependence of the heat capacity of biopolymer solutions between 4–400°K. Four distinct temperature regions were discovered, and experiments on these temperature intervals are given.

Methods of determining the numerical density of cell organelles described in literature were critically reviewed in a morphometrical and stereological study of muscle cell mitochondria (heart muscle cells, diaphragm cells, sceletal muscle cells). A review of the method described by WEIBEL and GOMEZ showed that the numerical density of the mitochondria depends to a great extent on their shape and not so much on their size distribution. For this reason serial sections should be used to determine the shape factor in biological objects of unknown geometric shape. Generally, the numerical densities of mitochondria determined by using the method proposed by DEHOFF and RHINES were higher than those obtained with the method described by WEIBEL and GOMEZ. This is attributed to certain corrections used in the former method. Elaborate computations are generally involved and the geometric shapes of the object examined must be known in order to determine the numerical density of cell organelles or of other biological structures. The numerous sources of error involved in these methods give this parameter the character of an objective estimate. For this reason it is recommended that the value obtained should be checked by determining a two-dimensional parameter. Our examinations of heart muscle mitochondria showed good agreement between the two parameters.

Based upon the method we developed to measure ethylene in very low concentrations (as low as 0.01 ppb in the ambient atmosphere) an experimental chamber was constructed and integrated in the measuring system for plant physiological studies. Parameters influencing the accuracy of the technique are evaluated. The pressure in the plant chamber increased 0.05 atm at a flow rate of 10 1/h during ethylene trapping. At this flow rate the ethylene production per seedling is independent of the number of seedlings used. The ethylene measured per seedling is directly proportional to the length of trapping time. Under standard conditions of chamber configuration and volume very small changes in ethylene content can be detected accurately in a very short time range. Our experimental arrangement allows kinetic studies of ethylene evolution by biological objects in a qualitative and quantitative manner. All methods used heretofore are more complicated and less accurate compared to the measuring system presented here. Its versatility is demonstrated for both in vitro and in vivo studies of ethylene production by bean seedlings. The application fields of the apparatus are discussed.

The grid sectioning technique has been used to obtain the two missing principal axis projections of orthorhombic catalase platelets and to measure directly the unit cell c-value. The negatively stained platelets have a unit cell c-dimension of half that proposed by Unwin (1975) from powder X-ray diffraction. The precision of the grid sectioning technique in positioning sections along a specimen axis shows that the growth fault lines usually observed on negatively stained catalase platelets are rows of missing molecules filled with stain. From these sections conclusions are drawn concerning the action of negative stain on a specimen, the microtomy process, and the specimen/supporting film interaction. Finally the value of microtomy for detailed structural analysis of biological objects is emphasized.

Durch den Zusatz von je 4% Saccharose, Harnstoff, Acetamid und Propionamid zu 0,666% Agar-Gel bleiben die kolloidchemischen Eigenschaften des Gels nahezu unverandert, dagegen wird die Ausbreitung der Serumprotein-Fraktionen wesentlich modifiziert. Obige polare Substanzen sind im Sinne eines steigenden Verteilungskoeffizienten (Olphase/wasrige Phase) angefuhrt. Als Testproteine dienen Serumalbumin, γ-Globulin, α1-Lipoprotein und α2-Makroglobulin. Die Ergebnisse der Modellversuche werden verglichen mit den Erfahrungen am biologischen Objekt. It has been proved that by the addition of 4% sucrose, urea, acetamide, and propionamide to 0,666% agar-gels, the colloidochemical properties are not changed, but the spreading by diffusion of serumprotein fractions is significantly altered. The polar substances which have been added are listed above in an increasing sequence of their partition coefficient (oil phase/water phase). Serumalbumin, γ-globulin, α1-lipoprotein, and α2-macroglobulin have been used as test-proteins. The results of these model-reactions are compared with corresponding experiences on biological objects.