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The combination of 3D printing and synthetic biology is a sustainable strategy to fabricate biological objects and systems that behave in a preprogrammed manner. Many microorganisms have been genetically engineered as cell factories for the biosynthesis of chemicals using fermentation, and 3D printing of living materials using these cells could lead to a new paradigm for biomanufacturing.

A new method of forming substrates (devices) with periodic micron surface grids for statistical analysis and visual characterization of ultra-small biological objects and microorganisms is suggested. For this aim an implantation by Ar+ of silicate glasses through surface masks as wire meshes is used to form surface periodic structures in the form of grating with cell sizes of 25 μm and a depth of 100 nm. Testing of novel types of devices was carried out applying scanning electron and atomic force microscopy, as well as EDX analysis using substrates with deposited bacteria as Bacillus subtilis.

This paper reports a feedback-based manoeuvre planning approach for automated nonprehensile selective micromanipulation of large, microscopic biological objects ( ∼ 100 μ m ). We employ ferromagnetic micro-particles as microrobots actuated via a global magnetic field produced by electromagnetic coils placed in quadrupole configuration. The microrobot motion is programmed to push the target object to the goal location. We employ a three-step approach comprising: (a) generate a collision-free optimal path between the initial and the commanded goal location, (b) generate a manoeuvre planning algorithm that invokes one of the three motion manoeuvres, namely, ‘approach’, ‘push’, and ‘align’ depending upon the instantaneous locations of the microrobot, target object, and the desired waypoint, and (c) deploy a simple proportional controller that determines the currents required in the electromagnetic coils that can produce a suitable magnetic field for executing the manoeuvre invoked by the manoeuvre planner. This paper reports a number of validation experiments conducted on both zebrafish, i.e., Danio rerio embryos and silica beads as target objects. We envisage that the developed inexpensive approach can be useful in robotic manipulation of biological objects with sizes in hundreds of microns including large biological cells, polyploid giant cancer cells (PGCC), multicellular spheroids, Dictyostelium slug, human oocytes, and autophagy candidates. We also believe that functionalising the microrobots with living cells or suitable chemicals will make it possible to perform on-chip biological experiments in future.

In the past, algorithms exploiting varying semantics in interactions between biological objects such as genes and diseases have been used in bioinformatics to uncover latent relationships within biological datasets. In this paper, we consider the algorithm Medusa in parallel with binary classification in order to find potential compounds to inhibit oral cancer. Oral cancer affects the mouth and pharynx and has a high mortality rate due to its late discovery. Current methods of oral cancer treatment, such as chemoradiation and surgery, fail to provide better chances for survival, warranting an alternative approach. By running Medusa on a data fusion graph consisting of biological objects, we incorporate binary classification to model the algorithm's association detection to discover compounds with the potential to mitigate the effects of oral cancer.

Background The assessment of the potential significance of synergistic interaction between adverse ecological factors acting together at the level of intensities found in the biosphere is still intriguing and unresolved problem. Objective This study aims to analyze synergistic effects for various biological objects, tests, and interacting agents to provide conclusive evidence of possible synergistic interactions of natural intensities of environmental factors on cell growth. Methods Four dose-effect curves were obtained for each object and interacting factors: after the individual action of agents, after their simultaneous action and theoretically expected curve after independent addition of the effects produced by each agent. The synergistic enhancement ratio (SER) and its dependence on intensities of agents were quantitatively estimated based on these curves. Results The extent of synergistic interaction was shown to be dependent on the intensity of physical factors or concentration of chemicals in such a manner that there were optimal conditions at which the greatest synergy may be achieved. The lesser the intensity of one of the agents applied, the smaller intensity of another agent has to be used to provide the highest synergistic interaction. In investigations where SER > 1, CI Conclusion The existence of optimal conditions providing the greatest synergistic effect and its dependence on the intensity of applied agents was demonstrated. Common patterns were identified. It is concluded that synergistic interactions are important for the evaluation of biological consequences and risk assessment from combined effects at low intensities of ionizing radiation, UV-light, electromagnetic fields, or small concentration of chemicals.

The advanced instrumental technique for research and control of the motivation of the experimental animals under the weak microwave electromagnetic radiation are suggested. The microwave is modulated by interval patterns. The results of these physiological and metabolites experiments showed that long-distance low-intensive, special coded microwave exposition can change the current motivations and corresponding behavior of animals. These results can be used in the studies of the fundamental brain mechanisms and in the medicine.

For the purpose of reducing uncertainties in the measurements of morphologically complex biological objects, the authors present a new automatic method, which takes advantage from the representation of the object in the form of the 3D geometric model obtained from CT-scans or 3D scanning. In this paper, the method is verified in real cases and compared with the traditional approaches.

Progressive motion of a multibody system consisting of equal rigid bodies in a resistive medium is considered. The bodies are connected consecutively, and between each pair of bodies the actuators are installed. The actuators can exert forces upon the two neighboring bodies so that the distance between them can change within prescribed limits. It is shown that, under the influence of these internal forces produced by the actuators and external resistance of the medium, the system can move progressively with a velocity changing periodically. The algorithm of locomotion is proposed and justified. The necessary and sufficient condition is obtained that ensures the possibility of this motion. The cases of linear and quadratic isotropic/anisotropic resistance forces depending on the velocity of moving bodies and directed against this velocity, are analyzed. The locomotion described in the paper resembles the motion of worms and other biological objects.

In the article the estimation of negative influence of transport building on environment is offered. Geoecological indicators of this estimation are developed. The negative impact on the environment must take into account all life cycle stages of the research object (product, design, activities); limitations in the use of the object (if a negative impact on the environment irreversible during exploitation); the list of environmental/biological objects that may be exposed to danger due to specific; the ability to reduce the negative impacts after preventive measures. The technologies of utilization of waste in the manufacturing of ceramics are developed to decrease the negative impact at all stages of the construction activity.

We present a synthesis method to fabricate framed carbon-based nanostructures having highly anisotropic shapes, in particular, the nanofork and nanoscalpel structures which are obtained systematically under optimized growth conditions. A theoretical model is developed to explain the formation of such nanostructures on Si cantilevers and W etched wires exposed to a focused electron beam. We then demonstrate the potentials of these nanostructures as functional tips for scanning probe microscopy. Owing to their anisotropic shapes, such tips can be very useful for nanolithography, nanosurgery of biological objects, and precise manipulation with surface particles. Overall, our method provides a simple and robust way to produce functional scanning probe microscopy tips with variable shapes and enhanced capabilities for different applications compared to standard cantilevers.

Fractal geometry is widely used to study the roughness of irregular curves and this has a number of biomedical and geological applications. However, many natural and biological objects are semi-fractal,multi-fractal or non-fractal objects, where the fractal dimension (FD) measure does not work. This paper proposes an irregularity index ( I c ) to quantify curve irregularity by measuring the change in the roughness of the segments of the curve with change in window sizes. The proposed index has been validated using synthetically generated curves having different degrees of roughness and the results showed linear relationship of the index with the roughness level (R 2 = 0 .99). Statistical significance using ANOVA was tested to determine the difference in the value of the index for curves having different irregularity for both I c and FD and it was found that only I c values showed significant difference among the different groups of curves with varying irregularity (p-value

In this paper, we present a ultraweak photon emission (UPE) measurement system to identify the biological death process. Using medical mouse, the relationship between the photon number of UPE and death process was investigated in our research work. The comparison between the normal living state and biological death process shows that there was an obvious increasing trend of the ultraweak photon emission number just before biological objects died. The results suggest that UPE may be used as a method to observe the physiology activities, and also identify the process of death and the state of living.

Identification of GM plants with their internal molecular-genetic qualities serves transformation of living organisms into identifiable commodities and objects of regulation. From molecular reductionist assumptions it also follows that scientific research is to be based on experiments that allow analysis of genetic influence in isolation. In this paper, I analyse molecular reductionism ‘in action’ by means of an ethnographic case study, focusing on the practices and transformations through which a field trial of transgenic trees created understanding of the risks or risklessness of the trees. The results show how the mobilisation of the field trial design, choosing of key analytical scales and formation of the research team stabilised the paths that experimentation was to follow. The scientists took the emerging inconsistencies and surprises calmly, indicating that unexpected events are an essential part of a scientific process. However, surprises could matter only in relation to the testing arrangements. Therefore, what could become visible and what could make a difference for the constitution of risk/risklessness were the fluctuations that the particular analytical assemblages defined as significant from the outset. Meanwhile, it was impossible to treat the trees and the field ecosystem as mutually constitutive. Nevertheless, there is no reason to think of knowledge production concerning transgenic organisms in deterministic terms. First, scientists are bound to be complexly engaged with the ecosystems that they are supposed to sort out. Second, consideration of the public lessons of experiments may elicit problems and limitations of molecular reductionism.

In this article, the results of the experimental and theoretical developments for equipping the station “DICSI”, created on channel K1.3 (a) of the (Siberia-2) storage ring of the Kurchatov Centre for Synchrotron Radiation and Nanotechnology are considered. Argumentation for the basic parameters of the X-ray optical systems is given, photos and the schemes of created equipments are presented, in addition, the results of the test experiments with the biological objects are considered.

In the review a comprehensive analysis is given of instrumental analytical approaches to control the activity of lipolytic enzymes and their substrates. A special attention is attached to the methods based on the biosensor technology. A number of electrochemical, optical and mechanical biosensors that were developed in several laboratories are analyzed in detail. In addition, perspectives are evaluated for the development of these biosensors and their practical application. It was concluded that biosensors may provide all practical demands which are in enzymology field at the express determination of lipase activity and triacylglycerol levels in biological objects.

The methodological and technical aspects of the biological objects study by the time-resolved X-ray diffraction technique are described with reference to muscle contraction. The results of relevant investigations into the structural dynamics of a living muscle during its contraction are presented.

The possibilities of examining patterned natural and mineralised biological objects, using X-ray synchrotron facilities, complemented by electron microprobe and optical analysis are reviewed. The objects under investigation include: petrified wood, speleothems, corals, shells of molluscs and remains of belemnites. All those objects have important information embedded in their patterned structure. Using microprobe type devices, one can disentangle the internal structure of the objects and reveal the hidden information. This information can be of great significance to climatic, geological, chronological, and ecological studies and specific examples in each category are shown, taken from our work and compared with the results of other authors where necessary. The added value of the X-ray and electron microprobe measurements in relation to the mass-spectrometric methods is shown for the specific cases. In addition, the results concern materials where organic and even biological material is combined with inorganic matter, like calcite, silica varieties and metal oxides. The investigation of such patterned objects as goethitized wood, composed of goethite, calcite and organic matter should therefore be of interest to materials scientists, synthesizing composite materials.

The using of medicinal clays in the form of an application leads to a change of macro- and microelement homeostasis in the internal medium of the organism. The character of this change of macro- and microelement contents in biological objects (hair, blood, urine) after clay treatment is described according to SR XRF data.

X-ray diffraction and fluorescent investigations of human hair were carried out using SR of VEPP-3. The small-angle techniques were used for ecological monitoring and medical diagnostics of pathological states of human organisms with the usage of non-invasive methods for express analysis of biological objects, including human and animal tissues: nails, wool and hair samples. Possibility using of hair fibre diffraction to test for pathological conditions is the subject of this paper. X-ray diffraction data allowed us to suppose the two-component structural model of the hair tissue.

Quantification of linear biological structures has important applications in neuroscience; for example, the length of neurotransmitter-specific axonal innervation or length of dendritic processes within particular brain structures. Until recently, however, there have been practical limitations in the application of stereological tools for the unbiased estimation of object length on tissue sections. The recent development of efficient new approaches allows for the wider application of theoretically unbiased sampling and estimation techniques that are devoid of the assumptions and models of earlier methods. In this review, we outline the historical background and recent advances in the estimation of total length for biological objects on tissue sections, including a practical method to estimate the length of cholinergic fibers using newly developed methods. These newer methods also take advantage of three-dimensional image datasets and virtual probes, techniques that may have wider application in quantitative morphometry.

The method of high-speed X-ray diffractometry with time resolution for small-angle studies of structural changes during muscle contraction is described. The parameters of the small-angle camera, devices for survival and control of muscle, the system for registration of diffraction patterns are considered. The algorithm for carrying out the experiment by using the time-resolved technique and steps of mathematical treatment of results are presented.

In visualizing very long DNA sequences, including the complete genomes of several bacteria, yeast and segments of human genes, we encounter fractal-like patterns underlying these biological objects of prominent importance. The method used here to visualize genomes of organisms may well be used as a convenient tool to trace, e.g., evolutionary relatedness of species. We describe the method and explain the origin of the observed fractal-like patterns. ” 2000 Elsevier Science Ltd. All rights reserved.

Experiments on the real-time in-line phase imaging of biological objects at the second generation synchrotron radiation source are reported. High intensity “pink” beam was obtained using the reduced electron beam energy of the accelerator. Optimal conditions for phase-contrast imaging at the low coherence source are discussed.

The use of an intelligent measurement technology at dairy farm based on the Near Infrared Monitoring (NIMo) of biological objects appears feasible and will enable more on-line data to be processed for better management. The pattern of near infrared spectrum for milk will change in correspondence to changes in cow's conditions i.e.; lactation Stage, feed, etc. Tt could be possible to organize feed backs in uniform system to optimize the feeding cow's treatment. The feasibility of a neural network to manage cows feeding was investigated in this study. The neural network was used to manage cow's feeding based on near infrared spectroscopy of its milk. The result show that it is feasible to manage cows feeding by using its milk NIR spectra.

In this paper we discuss the effect of microgravity on T cells and we present the data of studies with two new machines for 0 g simulations. Several experiments in space show that mitogenic T cell activation is lost at 0 g. Immunocytochemistry indicates that such effect is associated with changes of the cytoskeleton. Biochemical studies suggest that the lack of expression of the interleukin-2 receptor is one of the major causes of the loss of activity. In fact, interleukin-2 is the third signal required for full activation. In order to deepen our investigations we are now working with the free-fall machine, FFM, invented by D. Mesland, and with the random positioning machine, RPM, or three-dimensional clinostat, developed by T. Hoson. The FFM produces periods of free-fall lasting approximately 800 ms followed by bounces of 15-30 g lasting 45-60 ms. The RPM eliminates the effect of gravity by rotating biological specimen randomly around two orthogonal axes. While the FFM failed to reproduce the results obtained with T lymphocytes in space, the data from the RPM are in good agreement with those in real microgravity. In fact, the inhibition of the mitotic index in the RPM is 89% compared to static controls. The RPM (as the FFM) can carry markedly larger specimen than the fast rotating clinostat and thus allows to conduct comprehensive studies to select suitable biological objects for further investigations in space.

The description of the experimental station installed on 5-b th beam line of VEPP-3 storage ring (Budker Institute of Nuclear Physics SB RAS, Novosibirsk) is presented. The synchrotron radiation (SR) from viggler generating 2 beams is used. The station is intended for X-ray diffraction research of various biological objects and other materials in small and wide diffraction angles.

The possibility of using synchrotron radiation (SR) for obtaining the X-ray images of biological objects by the method of refraction radiography at the energies of 8.9 and 33.2 keV is shown. The results of experiments at the storage ring VEPP-3 (Novosibirsk) are presented. In comparison with a conventional X-ray source, the exposition time with SR is reduced by a factor of more than a thousand (approximately, down to 1–2 s), and the quality of images is improved.

Non-invasive methods of express analysis for mass monitoring of pathological states of human organism have been developed on the basis of X-ray fluorescence (XRF) elemental analysis of hair, nails, tooth enamel and skin. In addition, methods have been developed for studying sample preparations with the use of a universal X-ray fluorescence spectrometer mounted on a VEPP-3 storage ring. Data have accumulated over several geographical regions (Moscow Region, Chelyabinsk, Middle Asia, Novosibirsk Region, Maritime Region). The data of XRF analysis of hair samples from patients and animals mirror reliably differences in element concentrations. The methods can be useful in clinical medicine.

We consider the possibility to use liquid helium for some applied problems such as holography of micro-objects (including biological objects like macromolecules and viruses) with spatial resolution of the order of nanometers, microlithography, and for the creation of electron sources. In the first part we discuss the possibility of acoustic holography of micro-objects submerged in liquid helium. In the second part we discuss the possibility of electron holography when liquid helium is used as an emitter of electrons. In the third part we discuss some properties of such emitters which probably may be applied to microlithography where electrons are used.

The risks associated with the introduction of ultrasound contrast agents (UCAs) into the body and the subsequent insonation by diagnostic or therapeutic ultrasound are caused, in addition to microemboli and toxicity, by cavitation-conditioned phenomena. Microbubbles, which enhance ultrasound contrast, provide cavitation nuclei and may cause cavitation in the ultrasound field. Generally, in biological objects, cavitation phenomena can have chemical effects, such as production of free radicals, or can result in cell surface erosion by microjets. Microbubbles, which can travel in body fluids, could nucleate cavitation in a part of the body subjected to subsequent ultrasound or shock wave treatment. Therefore, the use of UCAs, which may cause or enhance cavitation under certain circumstances, should be restricted to cases where they are of proven benefit. Ultrasound or shock wave therapy of body parts in which UCAs can be entrapped should be performed with a sufficient time interval to allow for the elimination of cavitation nuclei.

In recent years some Biostack experiments including a wide spectrum of biological objects have been devoted to study of the radiobiological effects on dry seeds aboard recoverable satellites. Some impressive phenomena have been observed. Clearly, the large amount of energy deposited by the highly ionizing heavy nuclei of cosmic rays is the principal reason for the induced aberrations of the chromosomes of wheat root tip cells. A methodical description of the experimental arrangement and procedure of handling and evaluation of detectors is given. The preliminary physical and biological results from the experimental “wheat seeds” are presented.

Digital libraries are being built upon internet-based systems of heterogeneous information bases which contain texts, images, audio, video, and graphics. A relatively unexplored but important research area for digital libraries is the indexing of spatial objects and 3-D geometric information. This paper provides some new content-based approaches to this area. Experience gained from building a digital molecular biology library including spatially indexed biological objects is described.

Three french laboratories have participated in the Free Flyer Biostack experiment. Artemia cysts, tobacco seeds and rice caryopsis and embryos were used. Biological objects in monolayers were dead. In opposite, a large fraction of samples used in bulk survived. A stimulatory effect occurred in the first steps of development in Artemia cysts. In fact, the larval survival was unchanged or slightly reduced. In tobacco a drastic decrease in germination and survival rate was observed. Space flight did not induce genetic changes. In rice, results depend on the variety which was investigated; the growth rate stimulation in flight samples is discussed with respect to controls.

A scanned probe optical microscope allowing nondestructive studies of a wide range of objects and surface is described. The microscope utilizes a noninvasive optical trap to position a microscopic probe light source in immediate proximity to the studied object. We demonstrate the method experimentally and show theoretically its potential for optical imaging with subdiffraction limited resolution of, e.g., biological objects.

A new approach to treat the substates hierarchy in complex biochemical and physicochemical systems (such as spin glasses, proteins, various biological objects, etc.) is proposed. This approach introduces the possibility of taking into account energy-landscape fluctuations as well as correlations between the fluctuations in distinct scales and overlapping substates. Several proposals concerning the evaluation of energy-landscape fine-structure characteristics and other applications of the new method have been set forth.

Rousseau, D-D, 1990 Methods for the study of stratlgraphlcal records -- Introduction to Methods and Concepts m European Quaternary Stratigraphy " Palaeogeogr, Palaeochmatol, Palaeoecol, 80 I-6 The International conference "Methods and Concepts m European Quaternary Stratigraphy was held to take stock of the new developed concepts m Quaternary stratigraphy, to compare &fferent approaches and to evaluate the respectwe results m continental and marine environments The following papers, presented m this Issue, correspond to the theme "Methods for the study of stratlgraphlcal records ' They roughly indicate the average use of &fferent concepts developed m different dlsclphnes to Quaternary records Two biological objects are described m detad molluscs and pollen They are approached m two &fferent ways For the former, first of all by using a blogeographlcal approach based on the blome concept and secondly by trying to demonstrate the stratlgraphlcal value of mollusc assemblages m fluwal deposits For the latter, first of all by using a dynamxc approach to the vegetation cover of the middle mountain area of the Massif Central, France and secondly by using transfer functions to propose temperature and precipitation estimations from two long pollen sequences A last paper makes an evaluaUon of &fferent materml which can be ra&ocarbon dated and the rehablllty of the proposed dates, specmlly beyond 35,000 yr B P Ten years ago, European geologists who were dealing with Quaternary study met m Dijon to develop a common strategy concerning Quaternary stratigraphy (Chahne, 1980) The purpose was to homogenize and redefine a stratlgraphtcal approach accordmg to Hedberg's guide Three major recommendations were proposed (Paepe

A novel device called a “Fluid Integrated Circuit” (FIC) has been developed for the electrostatic manipulation of biological objects. The FIC is made with photolithographic micro-machining techniques used for the production of IC and LSI, by which all components for the manipulations are miniaturized and integrated on one substrate. The advantage of the FIC concept is twofold: firstly, channels, electrodes etc. can be made small to allow the handling of micrometer scale objects, and secondly, the electrodes and insulating walls of arbitrary shape can be made so that a flexible field design is possible. Dielectrophoretic force is used for the actuation of cells and biological molecules. Several cell handling devices have been designed and fabricated: a FIC electrical cell fusion device that realizes one-to-one cell fusion, a cell shift register for the storage and transport of individual cells, and a cell deflector for the classification and sorting of cells. The electrostatic orientation of DNA is observed under the high-strength field produced by micrometer-sized electrodes.

A station for the investigation of the fluorescence intensity and anisotropy decay of biological objects is described. The station has been installed on the synchrotron radiation (SR) source S-60 of P.N. Lebedev Physical Institute and can be extended to investigations of the spatial structure of lipoproteins and biological membranes.

wound and the underlying scull bone fracture ‐ was of a characteristically chopped origin. All the other injuries had signs of the infliction of some sawing implement. Besides, most lesions in soft tissues and bones were resulted from blows inflicted with a sawing instrument (a cutting saw edge, to be more exact). The other wounds shaped as a result of multiple sawing actions or a combination of blows and saw drawing. In the course of further enquiry and forensic medical examination of biological objects, the experts have managed to establish the size and accurate details characterizing the saw in question: its character, tooth spacing and angle, and particular features of saw teeth. The wound of the bone tissue resulted from the saw blows have proved to be the principal injury affording to reconstruct the details of the instrument, which is quite a rare case according to the literary references. The saw was found and removed later on when the area where the crime had been committed was subjected to further investigation. The forensic medical examination has made it possible to identify the given wound-inflicting implement.

Images of biological objects formed in the electron microscope are of such a nature that we can simplify the problem of three-dimensional reconstruction. One simplification is to make the assumption that the object can be represented as a Boolean three-dimensional matrix. In this paper we examine the problem of reconstructing two-dimensional Boolean matrices from their projections and conclude that surprisingly good reconstructions can be obtained using only four projections.

A review is given of the latest papers on the application of the spectral-isotopic method of determination of gas-forming impurities in organic and inorganic materials. Main attention is paid to a new kind of investigation, i.e. the development of spectroscopic methods for isotopic analyses of nitrogen, carbon, oxygen, and hydrogen in biological objects for use in analytical monitoring in biological experiments with “tracers”. A universal method is described for the preparation of natural samples, for the separation of the gases to be analyzed from the sample, and for their purification from the impurities. The main characteristics are given of the methods for individual determination of the above elements and for joint analyses of some elements (N 15 -C 13 -H 2 ) in one analytical cycle (spectrum excitation conditions, isotope concentration calculations, etc.). The characteristics of the methods have been compared with the results of other researches and the scope of our method for applications in biological investigations with tracers has been defined. The main results of spectral-isotopic method development in the traditional direction, i.e. for quantitative analysis of impurities in solid inorganic materials and for gas analysis, are produced.

A non-destructive method is described which makes possible the precise detection of respiration centres in the early avian embryo and of changes in their activity under the influence of drugs and other chemicals as well. A modified Clark-type oxygen sensor containing seven independent symmetrically arranged indicator electrodes and one common reference electrode, working either in the steady state or in the pulsing polarization regime, is placed onto the flat embryo surface and the signal of each indicator electrode is sampled and stored in multiple memories.

The degree of study of biological objects within the framework of the continuum approach is characterized in comparison with practical demands. Features of the construction of models of biological continuous media are discussed, in particular, the role of thermodynamic and biological considerations. Certain timely research directions are considered.

New trends in biometrics suggest that the dichotomy between metrical and non-metrical traits is artificial and transitional. Leaving the conventions referring to the exclusive use of anatomical landmarks combined with advanced biostereometrics, it should be possible to define complete biological objects down to their details using the same kind of parameters. The value of new techniques for measurement depends on the methods available for data analysis. A short survey of some current biostereometric methods is given with some remarks on technical characteristics and feasibility. The author's experience with the application of stereophotogrammetry to craniometrics shows this solution to be an advantageous alternative in most cases.

The problem of the interpretation of images of biological objects in the scanning electron microscope is discussed. The influence of preparative techniques, drying and coating methods on the final image is illustrated by reference to higher plant protoplasts. Methods for confirming the presence of new structural detail are suggested. An attempt is made to illustrate and introduce the need for a higher standard of interpretative and critical skill in the presentation of results obtained by means of scanning electron microscopy.