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The treatment of infections caused by OXA-48/CTX-M-coproducing Enterobacterales may be based on new beta-lactam/beta-lactamase inhibitors, such as ceftazidime/avibactam (CZA), or on high dose of meropenem (MER). However, bacterial density at the infection site may vary widely, and the inoculum effect of such antimicrobial strategies has never been specifically investigated. To determine if CZA or MER susceptibilities are impacted by high inocula of Enterobacterales co-expressing both enzymes: OXA-48 like and CTX-M.Determination of an inoculum effect was performed with a standard inoculum of 10Thirty-nine isolates of ceftazidime-resistant Enterobacterales were included of which 27 (70%) co-expressed OXA-48 + CTX-M-15, 6 (15%) OXA-48 + CTX-M-14, and 6 (15%) OXA-181 + CTX-M-15. The susceptibility to the CZA combination was preserved whatever the inoculum used. Regarding MER, 24 (61.5%) of the isolates were susceptible to MER with the standard inoculum, 19 (48.7%) with a twofold increase, and only 15 (38.5%) with a tenfold increase.We showed that in vitro inoculum effect was observed with meropenem but not with CZA for OXA-48- combined with CTX-M-producing Enterobacterales.

Objective Marijuana is the most commonly used illicit drug in France among diverse social circles. According to the ANSM report published in 2018, hospitalization of young children following cannabis exposure keeps increasing while concentration of Δ-9-tetrahydrocannabinol (THC) is higher and child poisoning with cannabis is more severe than ever. The effects of long-term THC exposure or recurrent intoxication during childhood may not be immediately perceptible and are poorly described in the literature. We reviewed poisoning conditions, diagnosis and monitoring of unintentional cannabis intoxication in children in order to suggest a standardized procedure for biological monitoring and follow-up. Methods We conducted a retrospective observational study of admissions from 2010 to 2018 in the paediatric department at the University Hospital of Rouen. All children Results Thirty-three children were included and more than 70% were younger than 2 years old. Most cases were caused by accidental resin oral ingestion (85%) and intoxications were more frequently found in a family context (75%). Less than half of parents reported unintentional cannabis ingestion on arrival to emergency. Thirty children presented at least one acute neurologic symptom, 34% ophthalmological symptoms and less suffering from respiratory and cardiovascular impairment. All of them were hospitalized at least 24 h. Six of them underwent a lumbar puncture and one received intravenous antibiotics and antivirals. Only 12 quantitative blood tests using liquid chromatography-tandem mass spectrometry were performed. Only 30% of children were subject to a follow-up few months later. Three monitoring were performed by HPLC-MS/MS in hair samples, 7 in urines and one child had twice quantitative blood test. Discussion These data demonstrate a great variability in the biological management and follow-up according to prescribers who are not always well informed about the methodologies available. Clinicians should be careful about cannabis intoxication, especially concerning young children admitted in emergency units with unexplained neurological symptoms. We suggest a helping chart for biological diagnosis and monitoring, relying on the parent's good faith about their children cannabis ingestion. It includes hair, urine and blood analysis. The parents’ drug history (either therapeutic or recreational) should be investigated to avoid unnecessary and invasive tests and treatments. After initial diagnosis, the tests should usually include a quantitative blood test for the determination of THC and its metabolites to evaluate the severity of the intoxication and a plasma or blood bank should be stored for any further analysis. Furthermore, voluntary poisoning must be considered, especially if recurrent intoxication occurs. Depending on results, repeated hair analysis, toxicological screenings in blood and/or urines may be required several months later and may be reportable to a subsequent child protective services report. Nevertheless, recent data highlight some limits of hair sampling to discriminate acute from chronic exposure in children under 3 years old [1] . Conclusion Cannabis intoxication in young children is becoming a more common problem and this report highlights the need to standardize procedures for biological monitoring and follow-up.

Implant breakage is a well known complication of intramedullary nailing and many techniques are described to remove the distal part of a nail. A major disadvantage of all the techniques described is the requirement for an image intensifier in the OR. No technique under direct visual control has been described in the literature. With the technique of IBE (intramedullary bone endoscopy) we would like to introduce a new endoscopic procedure for removal of a broken nail under direct visual control. The intraoperative use of an image intensifier is not necessary for this new procedure.

The basics of electron energy loss spectroscopy (EELS) performed in the context of a scanning transmission electron microscope are described. This includes instrumentation, information contained in an EELS spectrum, data acquisition and processing, and some illustrations by a few examples.

The morphology of islands grown on surfaces from soft-landed clusters has been investigated by electron microscopy. Compact islands have been observed on amorphous carbon surfaces, whereas an evolution from compact to ramified shapes occurs on graphite surfaces as the mean size of deposited clusters increases. Moreover, by increasing the surface defect density on graphite, a continuous variation of the island morphology is observed, from extended ramified shapes to small compact shapes. In order to account for the island morphologies observed, we propose a crude model involving a competition between the time for aggregated clusters to coalesce and the time interval between successive arrivals of clusters to grow the islands. It shows that there exists a critical island size R 0 dividing island shapes into compact shapes for R R 0 and into ramified shapes for R > R 0 . This critical size R 0 varies as a function of the incident cluster size. Relying on our experimental results, we show how the morphology of the islands can be controlled by the size of the incident clusters and the presence of surface defects.

Neutral antimony clusters produced by a gas aggregation source have been deposited at room temperature on thin films of amorphous carbon and cleavage surfaces (0001) of graphite. Antimony islands generated from different mean size distributions of preformed clusters Sbn(n = 4, 90, 150, 250, 600, 2000) have been investigated by transmission electron microscopy. Only compact islands have been observed on amorphous carbon, whereas an evolution from compact to dendritic shapes occurs on graphite substrate as the mean size of the deposited clusters increases. For clusters containing more than 150 atoms the dendritic islands exhibit a fractal character whose dimensional analysis yields a fractal dimension of 1.63 ± 0.07. The different models for island growth are discussed in the light of these results.

Background Carbon nanotubes (CNT) are a family of materials featuring a large range of length, diameter, numbers of walls and, quite often metallic impurities coming from the catalyst used for their synthesis. They exhibit unique physical properties, which have already led to an extensive development of CNT for numerous applications. Because of this development and the resulting potential increase of human exposure, an important body of literature has been published with the aim to evaluate the health impact of CNT. However, despite evidences of uptake and long-term persistence of CNT within macrophages and the central role of those cells in the CNT-induced pulmonary inflammatory response, a limited amount of data is available so far on the CNT fate inside macrophages. Therefore, the overall aim of our study was to investigate the fate of pristine single walled CNT (SWCNT) after their internalization by macrophages. Methods To achieve our aim, we used a broad range of techniques that aimed at getting a comprehensive characterization of the SWCNT and their catalyst residues before and after exposure of murine macrophages: X-ray diffraction (XRD), High Resolution (HR) Transmission Electron Microscopy (TEM), High Angle Annular Dark Field-Scanning TEM (HAADF-STEM) coupled to Electron Energy Loss Spectroscopy (EELS), as well as micro-X-ray fluorescence mapping (μXRF), using synchrotron radiation. Results We showed 1) the rapid detachment of part of the iron nanoparticles initially attached to SWCNT which appeared as free iron nanoparticles in the cytoplasm and nucleus of CNT-exposed murine macrophages, and 2) that blockade of intracellular lysosomal acidification prevented iron nanoparticles detachment from CNT bundles and protected cells from CNT downstream toxicity. Conclusions The present results, while obtained with pristine SWCNT, could likely be extended to other catalyst-containing nanomaterials and surely open new ways in the interpretation and understanding of CNT toxicity.

Among electron beam microanalytical techniques, electron energy loss spectrometry (EELS) offers unique advantages in terms of information content, sensitivity, limits of detection. This paper describes new methods and tools for acquiring families of spectra over many pixels on the specimen, i.e. spectrumimages, and for processing them. Applications in different fields of research, both in materials science and in life sciences, demonstrate the potential impact of the technique for characterizing nano-sized structures.

With their first scanning transmission electron microscope (STEM), Albert Crewe and his collaborators have succeeded 40 years ago in bringing to reality a dream for all electron microscopists, to see individual atoms. In the derivation of Crewe's pioneering work, the present review describes various historical and present steps, involving continuous instrumental and methodological developments as well as the preparation of suitable specimens. They have lead to the identification of individual atoms by electron energy-loss spectroscopy (EELS) and to the demonstration of atom-by-atom spectroscopy. Beyond these spectacular successes which open wide fields of use, most recent technical achievements, such as the introduction of monochromators on the incident electron beam or of optical spectrometers for recording spectra (in the visible as well as in the X-ray domain), will undoubtedly lead to refine the accessible signature of single atoms and molecules.

Proximal intercessory prayer (PIP) is a common complementary and alternative medicine (CAM) therapy, but clinical effects are poorly understood, partly because studies have focused on distant intercessory prayer (DIP).This prospective study used an audiometer (Earscan(R) 3) and vision charts (40 cm, 6 m "Illiterate E") to evaluate 24 consecutive Mozambican subjects (19 males/5 females) reporting impaired hearing (14) and/or vision (11) who subsequently received PIP interventions.We measured significant improvements in auditory (P0.003) and visual (P0.02) function across both tested populations.Rural Mozambican subjects exhibited improved audition and/or visual acuity subsequent to PIP. The magnitude of measured effects exceeds that reported in previous suggestion and hypnosis studies. Future study seems warranted to assess whether PIP may be a useful adjunct to standard medical care for certain patients with auditory and/or visual impairments, especially in contexts where access to conventional treatment is limited.

CD4+ T cells contribute to disturbances of pancreatic microcirculation after cold and even after warm ischemia/reperfusion (I/R). The aim of this study was to investigate a possible protective role of FTY720 (fingolimod) in this setting. In an in vivo model (42 Wistar rats), ischemia of the pancreas was induced for 60 minutes under anesthesia with xylazin/ketanest. Sham-operated (SO) (I), untreated ischemic (II), and treatment group with FTY720 pre-treatment (1 mg/kg body weight IV) (III) were investigated. The effect of FTY720 on I/R injury was assessed by in vivo microscopy 30–90 minutes after reperfusion and by measurement of serum lipase. In the untreated ischemic group (II), capillary constriction to 85.3 ± 6.3% of SO diameters and a reduction of functional capillary density to 67% was found. After 30 minutes of reperfusion, the number of T cells in capillaries was increased (165.7%; P < .05 vs I). FTY720 pretreatment reduced this number to 54.2% of SO (P < .05 vs II). Likewise, the number of adherent leukocytes in capillaries (145.4 ± 11.2% of SO) was reduced in group III (109.3 ± 11.4%; P < .05 vs II), leading to an improvement in functional capillary density in the treatment group (98.2 ± 2% of SO; P < .05 vs II). According to improved microcirculation, lipase values were reduced in the therapy group (P < .05). In conclusion, FTY720 ameliorates the microcirculatory and biochemical manifestations of pancreatic I/R injury by preventing T-cell infiltration.

The conditions for the use of Electron Spectroscopic Imaging (ESI) in the observation of DNA molecules adsorbed on carbon film are described. The Zeiss 902 electron microscope with its built-in spectrometer allows original modes of imaging, such as energy-filtered annular dark-field. The six different modes of imaging are illustrated with either positively stained or metallized DNA preparations to show the resulting important differences in contrast. The very strong contrasts obtained in annular or spectroscopic dark-field modes on specimens presenting a very low contrast in traditional bright-field are very useful for the observation of biological macromolecules. The advantages of some observation modes for imaging different types of preparations are discussed.

Developments in instrumentation are essential to open new fields of science. This clearly applies to electron microscopy, where recent progress in all hardware components and in digitally assisted data acquisition and processing has radically extended the domains of application. The demonstrated breakthroughs in electron optics, such as the successful design and practical realization and the use of correctors, filters and monochromators, and the permanent progress in detector efficiency have pushed forward the performance limits, in terms of spatial resolution in imaging, as well as for energy resolution in electron energy-loss spectroscopy (EELS) and for sensitivity to the identification of single atoms. As a consequence, the objects of the nanoworld, of natural or artificial origin, can now be explored at the ultimate atomic level. The improved energy resolution in EELS, which now encompasses the near-IR/visible/UV spectral domain, also broadens the range of available information, thus providing a powerful tool for the development of nanometre-level photonics. Furthermore, spherical aberration correctors offer an enlarged gap in the objective lens to accommodate nanolaboratory-type devices, while maintaining angström-level resolution for general characterization of the nano-object under study.

The spatial resolution of an inelastic scattering process, such as a core excitation, governs the ultimate spatial resolution of an EELS (electron energy loss spectroscopy) measurement. An experimental study of the attainable resolution has been made through a detailed analysis of the structure of energy-filtered images on a characteristic edge (uranium O 45 ), as compared to the simultaneously recorded annular dark field images. When it has been possible to select specimen areas with a suitable random distribution of point objects (subnanometer uranium clusters), an upper limit of the degradation of the resolution is of the order of 0.3-0.4 nm for a 100 eV loss.

Carbon nanotubes (CNT) are cylinders with diameters in the nanoscale range, possessing unique properties that make them candidates to promising applications. The forecast increase of CNT use in manufacture, which will lead to an increase of human exposure, highlights the urgent need for a better understanding of the potential human health impact of CNT. Since the respiratory tract could be the main route of exposure to these volatile materials, studies of the effects of CNT on cells involved in the immune respiratory response — murin macrophages in the present study- are of special relevance.

International audience; X-ray fluorescence microscopy (μXRF) is applied for the first time to study macrophages exposed to unpurified and purified single-walled (SW) and multiwalled (MW) carbon nanotubes (CNT). Investigating chemical elemental distributions allows one to (i) image nanotube localization within a cell and (ii) detect chemical modification of the cell after CNT internalization. An excess of calcium is detected for cells exposed to unpurified SWCNT and MWCNT and related toxicological assays are discussed.

The imaging parameters of the scanning transmission electron microscope (STEM), in particular the defocus, can be obtained from a focal series of phase contrast images of an amorphous carbon film. By using a tilted specimen the phase contrast transfer characteristic (PCTC) and the mean-square contrast have been determined for a specific instrument. The PCTC contains all the information about the defocus dependence of the phase contrast. The results agree well with those obtained from a focal series of a non-tilted object and with the theoretical predictions.

Energy-filtering transmission electron microscopy (EFTEM) allows the determination of elemental distributions out of a sequence of energy filtered images. Combined with electron tomography, EFTEM is a powerful tool to obtain three-dimensional chemical maps from sub-cellular structures. However, there is no existing software in the public-domain for the computation and analysis of 3D-chemical maps. Here, we present a Java-based program to compute 3D-elemental distribution. This program is available as a set of plug-ins for the public-domain Java image processing program Image J inspired by NIH Image. Its implemented algorithms have been successfully applied to the three-dimensional localization of iron granules in semi thin (200 nm) epon sections from the vent worm Riftia pachyptalia.

The aim of this study was to investigate to what extent caregivers of schizophrenia patients suffer from psychiatric and psychosomatic symptoms themselves; furthermore, whether there are differences between parents and spouses.51 parents and 52 spouses of people with schizophrenia were interviewed regarding psychiatric and psychosomatic troubles using standardized questionnaires and diagnostic methods.A considerably increased prevalence of depressive disorders was found compared to the level in the general population. As well as mothers and wives, caregivers of patients with severe impairments of psycho-social functioning were particularly affected. The severity of the patient's disease and the caregiver's mental problems are significant predictors of psychosomatic complaints in parents and spouses. In addition, caregivers visit physicians more frequently, in particular family doctors, psychiatrists and psychotherapists.The results support the hypothesis that the burden carried by caregivers of severely affected schizophrenia patients increases their risk of becoming ill, which, as a consequence, leads to a greater use of medical resources. Specific offers of health care and advice on preventative measures appear to be necessary in order to preclude health impairments to caregivers as early as possible.

The aim of this study was to compare financial burden of spouses, whose relative suffers from schizophrenia, depression or anxiety disorder. 151 spouses filled in the questionnaire about illness related expenses and financial loss. Additionally they estimate their subjective burden according to these experienced costs. Direct cash expenditures on behalf of the patients' illness were reported by 66 % spouses. In the sampling the amount of spent money did not differ statistically, however spouses of patients with anxiety disorder emphasised experiencing financial strain and described more often subjective economic disadvantages. Although most spouses of patients with psychiatric disorders experience illness related financial disadvantages, these costs were usually not considered as serious problem or as burdensome. Based on a subjective hierarchy of burdens financial problems can be regarded as less important for spouses of patients with mental illness. Thus, not only the material, but also the immaterial costs of care giving spouses should be taken into consideration when planning health policy decisions.

The German Adaptation of the Verona Service Satisfaction Scale: An Instrument for Patients' Satisfaction with Mental Health Care.Measuring effectiveness and quality of care became an important topic in psychiatry. Considering that objective criteria were not sufficient in the past, the subjective perspective gained growing interest. Client satisfaction is an important variable to evaluate psychiatric care. Patient satisfaction can influence treatment outcome as well as it determines the psychiatric system itself.The Italian original version of the Verona Service Satisfaction Scale (VSSS-54) was translated and adapted to the German language. The instrument has been tested in the project "Cost-effectiveness of psychiatric service systems". The process of development, the psychometric testing and the practical application of the German version will be presented in this paper. Additional advantages and disadvantages are discussed.As psychometric properties of the instrument correspond to conventional standards, they are comparable with the results of an international study. The drop out of items cannot be controlled, therefore analysing the data is difficult.Although the VSSS shows various methodological limitations, it is at the moment an appropriate instrument for measuring patient satisfaction in the German language.

The development and the psychometric testing of the German version of the Camberwell Assessment of Need-EU will be presented.The internal consistency of the subscales total needs, met needs and unmet needs was tested by the application of the CAN-EU on a representative sample of 307 patients with schizophrenia according to ICD-10 F20.0. Test-retest-reliability and inter-rater-reliability was tested with a sub-sample of 41 patients.The internal consistency and the test-retest-reliability of the German version of the CAN-EU is satisfying and slightly higher in comparison with the other European versions. The inter-rater-reliability is also satisfying but smaller in comparison with the other European versions.In general, the psychometric properties of the German version of the CAN-EU are satisfying but the lower inter-rater-reliability in comparison with the other European versions suggests that more precise coding rules for the German version of the CAN-EU must be formulated to improve the inter-rater agreement of the instrument.

Aims of the study are the analysis oft the structures and influence factors causing direct costs of schizophrenic diseases by means of international standardized assessment instruments.Annual costs of treatment were assessed for a sample of 258 patients with the diagnosis of schizophrenia (ICD-10 F20) by means of the German version of the CSSRI. For the analysis of cost variance a regression model was computed using functional level (GAF), symptoms (BPRS 4.0), needs for care (CAN), service satisfaction (VSSS) and subjective quality of life (LQoLP) as predictors.The average yearly treatment costs for the study sample were 12 726,- DM. Costs for sheltered accommodation and for psychiatric inpatient treatment were found to be the largest elements of the entire costs followed by the costs for ambulant medications. Results of the regression analysis show that illness history, the severity of symptoms and the need for care explain the greatest proportion of variance.The standardized instruments developed in the project enable a systematic and international comparable assessment of the costs in the treatment of schizophrenic diseases. Furthermore the instruments allow to explain 38 % of the cost variance. The impact of the severity of symptoms under statistical control of the functional impairment and the needs for care suggests that an effective reduction of symptoms could lead to savings in the entire treatment costs. However, the great influence of the illness history and, irrespective of the functional impairment, the need for care show that the possibilities for cost savings in the treatment of schizophrenia are generally low.

In the project "Cost-effectiveness of psychiatric service systems. A European comparison" a German version of instruments for the assessment of needs for services (CAN-EU), service satisfaction (VSSS-EU) relatives' burden of care (IEQ-EU) and costs of psychiatric services (CSSRI-EU) was developed in close cooperation with the EPSILON Study group.The English original versions of the instruments were translated into German and a back-translation into the original language was carried out by a second translator. The back-translation was screened by the first author of the original version. The German versions of all instruments were tested for comprehensibility and practicability by means of focus groups. The internal consistency of all instruments were tested on a representative sample of 307 patients with schizophrenia according to ICD-10 F20. Test-retest reliability and inter-rater reliability was tested by a sub-sample of 50 patients.Psychometric properties of the translated instruments will be presented and discussed.Statistical methods for the assessment of the reliability coefficients were identical with those of the EPSILON study, therefore the psychometric properties of the German version of the CAN-EU are directly comparable with the other European versions of the instrument.

The German Version of the Involvement Evaluation Questionnaire (IEQ-EU), developed for the assessment of burden on relatives of mentally ill people will be presented. Also the results of the reliability analysis will be presented.After translation and adaptation of the Dutch version of the IEQ-EU into German, the instrument was tested in the study "Cost-effectiveness of psychiatric service systems".The internal consistency was tested on a sub-sample of 138 relatives and the Test-Retest-Reliability on a sub-sample of 37 relatives. The internal consistency (Cronbachs alpha) is moderate or good and slightly lower in comparison with the other European versions. With the exception of one subscale the results for the intraclass correlation coefficient are equal to the European versions.The IEQ-EU is an instrument with moderate or good psychometric properties. It covers all important domains, is easy to understand and not time-consuming.

Psychiatric health services research has to consider health economic points of view more than before as a result of the present-day financial problems in our health care system. Therefore an instrument was developed, which is suitable for the evaluation of cost of mental health care in Germany.The Client Sociodemographic and Service Receipt Inventory (CSSRI-EU), which was developed in the UK, was adapted to the German situation and for the first time used in a cost-effectiveness-analysis of mental health care. The adaptation process of the instrument and the practical application are explained and pros and cons considered.The German adaptation of the CSSRI-EU has proven effective in practical application. The instrument offers feasible solutions for many problems with the cost of mental health care. The instrument can be used for the calculation of direct and indirect costs and gives information about service utilization and medication profiles of the clients.The German adaptation of the CSSRI-EU is a feasible instrument for the evaluation of the cost of mental health care in Germany.

For the evaluation of the effectiveness of psychiatric service systems internationally standardised instruments for the assessment of the outcome and the costs of psychiatric and psychosocial treatment and care are increasingly needed. Beside the measurement of objective facts there is a growing importance of the consideration of the subjective perspective of patients and relatives. In the research project "Cost-effectiveness analysis of psychiatric service systems in the European comparison" of the Research association for Public Health in Saxony, developments were worked out, in close cooperation with the BIOMED-2 project "European Psychiatric Services: Inputs Linked to Outcome Domains and Needs", German versions of five European standardized instruments for the assessment of needs for care, treatment satisfaction, burden of care on relatives, quality of life and service costs. The psychometric properties of the instruments were tested within the framework of a longitudinal study with 307 patients with the diagnosis of schizophrenia. As a result of this study, German versions of all relevant European instruments for psychiatric service evaluation are now available.

Electron energy-loss spectroscopy (EELS) is widely used to identify elemental compositions of materials studied by microscopy. We demonstrate that the sensitivity and spatial resolution of EELS can be extended to the single-atom limit. A chemical map for gadolinium (Gd) clearly reveals the distribution of Gd atoms inside a single chain of metallofullerene molecules (Gd@C 82 ) generated within a single-wall carbon nanotube. This characterization technique thus provides the “eyes” to see and identify individual atoms in nanostructures. It is likely to find broad application in nanoscale science and technology research.

The design of the scanning transmission electron microscope (STEM) has been conceived to optimize its detection efficiency of the different elastic and inelastic signals resulting from the interaction of the high energy primary electrons with the specimen. Its potential use to visualize and measure biological objects was recognized from the first studies by Crewe and coworkers in the seventies. Later the real applications have not followed the initial hopes. The purpose of the present paper is to describe how the instrument has practically evolved and recently begun to demonstrate all its potentialities for quantitative electron microscopy of a wide range of biological specimens, from freeze-dried isolated macromolecules to unstained cryosections. Emphasis will be put on the mass-mapping, multi-signal and elemental mapping modes which are unique features of the STEM instruments.

Electron energy loss spectrometry--EELS, and energy dispersive X-ray microanalysis--XRMA, were used to study the elemental composition of mitochondrial dense granules-mdg. The study was performed on dry cut thin sections (80-200 nm) of freeze-dried and low temperature embedded cartilage. Results obtained by means of XRMA clearly showed high phosphorus and calcium content in the mdg. Using EELS at 100 kV primary voltage we found that small concentrations of elements (i.e. below typically 1% atomic weight) are difficult to analyze and map, this especially in sections thicker than 50-60 nm. Surprisingly, analysis of calcium can be successfully performed on thicker sections though the edge lies above the carbon K edge while this is not possible for the phosphorus edge which is located at lower energies. This is likely due to the edge shapes (sharp for calcium and delayed for phosphorus), and to the more intense contribution of multiple low loss scattering in the background for phosphorus between 100 and 130 eV. By means of EELS elemental mapping a centrally located core was found in numerous mdg. In the calcium map the signal was strongest in the middle of mdg which corresponds to the area of reduced carbon signal. We found that carbon maps might be used for high resolution structural studies of chemically unfixed and anhydrously processed biological tissues. As carbon is the main constituent of Lowicryl resin its distribution is reversed to the distribution of biological tissue in which the proportion of carbon is lower, but is proportional to water content in the specimen in vivo. Use of EELS in combination with electron microscope with accelerating voltages in range of 140-200 kV together with anhydrous techniques of the tissue preparation will provide a new type of information which might lead to better understanding of the etiology and function of small structures in the cell.

Criteria for optimum focus are reviewed within the framework of different theoretical descriptions for the STEM. The behavior of the generalized spread function t 1 ( r ) and t 2 ( r ) is calculated for three major situations: Scherzer focus, STEM optimum focus for ADF and microanalysis, minimum phase contrast focus. Experimental evidence is shown to support qualitatively the theoretical analysis.

Chemical mapping on individual metal clusters in the nanometer range is achieved by processing sequences of energy-filtered images recorded at different energy losses before and after a characteristic edge. The experiments are performed with a dedicated FEG-STEM delivering a typical 0.5 nm probe on the surface of a thin carbon layer supporting the small aggregates of uranium and terbium. A quantitative analysis of the data in the annular dark field image and in the characteristic uranium map shows that the elemental identification of numbers of atoms below 10 can be performed with good signal-to-noise ratio. Consequently, detection limit values of the order of one atom are accessible within the presently used experimental conditions.

Energy filtered imaging of thick biological specimens was analysed using a dedicated STEM fitted with an energy loss spectrometer and interfaced with a sophisticated data collection setup. All images were digital, thus permitting a quantitative analysis of the data. We also present a mathematical explanation of the data, which is useful in pradicting the quality of thick specimen images formed with energy filtered electrons. It is known that increasing specimen thickness leads to a decrease of the zero energy loss intensity and an increase in higher (multiply scattered) energy loss electrons. We show that contrast decreases gradually with increased energy loss but, most important, the signal to noise ratio is maximal at an energy loss position slightly below the intensity maximum. This is the optimal position for imaging thick specimens. Moreover our studies confirm that the following parameters have similar effects on the energy loss spectra: (1) increased thickness (t); (2) higher average Z number elements (or lower mean free path Ai); and (3) lower primary voltage (V0).

L'observation d'echantillons de CuSi 4 % par microscopie electronique a tres haute tension nous a conduits a etudier le contraste de diffraction de defauts d'empilement par comparaison detaillee des micrographies electroniques aux profils theoriques correspondants. Dans un premier temps nous avons evalue dans le cristal parfait, les valeurs, en tres haute tension de certains parametres (distances d'extinction, coefficients d'absorption) s'introduisant dans la theorie dynamique a N ondes. Des considerations simples sur les interferences entre les differents champs d'onde peuvent expliquer le contraste observe des defauts d'empilement, l'origine par exemple d'une structure fine sur les images en fond noir. Nous concluerons, dans ce travail, que les regles de contraste de tels defauts sont pratiquement les memes en tres haute tension (1 MV) et en basse tension (100 kV).

We used a high-resolution STEM to attempt to recognize the spatial localization of the macromolecular components of ribosomes isolated from Tetrahymena pyriformis. Images obtained either by the annular dark field detector or by the ratio-contrast mode (Z-contrast) show a ribosome as constituted of rounded dark areas, the number and size of which are compatible with those of the protein molecules recognized by biochemistry. Images of different ribosomes, when similar orientations are observed, exhibit a roughly constant pattern of the dark areas. A set of images of a tilted ribosome allows to recognize that some masses are in fact two more superimposed components. We propose that the dark areas represent essentially the proteinaceous architecture of the ribosome.

Amorphous thin foils of Fe-Gd alloys with very different compositions are prepared by vacuum evaporation. On well characterized specimens (structure, concentration, thickness, homogeneity), energy loss measurements have led to the determination of the electron excitation spectrum between 5 and 150 eV and Lorentz microscopy observations have been used to visualize the local magnetization distribution.