bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of longevity compounds with minimized probabilities of side effects
Authors: Janssens Georges E. , Houtkooper Riekelt H.
Published: June 2020

It is hypothesized that treating the general aging population with compounds that slow aging, geroprotectors, could provide many benefits to society, including a reduction of age-related diseases. It is intuitive that such compounds should cause minimal side effects, since they would be distributed to otherwise healthy individuals for extended periods of time. The question therefore emerges of how we should prioritize geroprotectors discovered in model organisms for clinical testing in humans. In other words, which compounds are least likely to cause harm, while still potentially providing benefit? To systematically answer this question we queried the DrugAge database—containing hundreds of known geroprotectors—and cross-referenced this with a recently published repository of compound side effect predictions. In total, 124 geroprotectors were associated to 800 unique side effects. Geroprotectors with high risks of side effects, some even with risk for death, included lamotrigine and minocycline, while compounds with low side effect risks included spermidine and d-glucosamine. Despite their popularity as top geroprotector candidates for humans, sirolimus and metformin harbored greater risks of side effects than many other candidate geroprotectors, sirolimus being the more severe of the two. Furthermore, we found that a correlation existed between maximum lifespan extension in worms and the likelihood of causing a side effect, suggesting that extreme lifespan extension in model organisms should not necessarily be the priority when screening for novel geroprotectors. We discuss the implications of our findings for prioritizing geroprotectors, suggesting spermidine and d-glucosamine for clinical trials in humans.
Mind-Mindedness and Stress in Parents of Children with Developmental Disorders
Authors: Larkin Fionnuala , Hayiou-Thomas Marianna E. , Arshad Zaynah , Leonard Matthew , Williams Frances J. , Katseniou Nicoletta , Malouta Rania N. , Marshall Charlotte R. P. , Diamantopoulou Maria , Tang Etonia , Mani Sneha , Meins Elizabeth
Published: June 2020

Relations between mind-mindedness (assessed using the describe-your-child interview) and stress were investigated in parents of children with developmental disorders (ADHD, n = 51, ASD, n = 23, Down’s Syndrome, n = 38, and 22q11.2 Deletion Syndrome, 22q11.2DS, n = 32) and typically-developing children (n = 89). Mind-mindedness did not differ across diagnostic groups, and mind-mindedness predicted parenting stress across groups. Parenting stress was lowest in the typically-developing and Down’s Syndrome groups. Across all groups, mind-minded and positive descriptions predicted lower parenting stress, and negative descriptions predicted higher stress. In the developmental disorder groups, describing the children with reference to their disorder was negatively correlated with mind-mindedness. Results are discussed with regard to interventions for families where children have developmental disorders.
Normativity, system-integration, natural detachment and the hybrid hominin
Authors: Moss Lenny
Published: June 2020

From a subjective point of view, we take the existence of integrated entities, i.e., ourselves as the most unproblematic given, and blithely project such integrity onto untold many “entities” far and wide. However, from a naturalistic perspective, accounting for anything more integral than the attachments and attractions that are explicable in terms of the four fundamental forces of physics has been anything but straightforward. If we take it that the universe begins as an integral unity (the singularity referred to as “the cosmic egg”) and explodes into progressive stages of internal detachment, then we can also fathom the idea that eddies of relative detachment becoming increasingly integral. Helmuth Plessner made a powerful case for the onset of “positionality” constituting one of the major transitions in nature. Surely, the emergence of “entities” (i.e., life-forms) that position themselves in relation to their surround marks a decisive transition in relative levels of detachment and some would say “autonomy.” It would follow, with no less force, that where and when entities can be seen to be normatively integrated, and indeed to be the agents of their own normativity, that another threshold of detachment has been crossed. The paper introduces and explores the idea that normativity, embedded in a wide-ranging theory of natural detachment, can be considered an emergent force of nature that is requisite to accounting for levels of integration beyond that which is explicable in terms of the four fundamental forces of physics. Following this line of enquiry, we argue that the first expression of a fully, normatively-integrated life-form is neither a spoken language user nor for that matter an individual but rather the neoteny-based, Homo erectus Group. In so doing we claim to have made an inroad into embedding the force of normativity into a wide-ranging naturalist framework, to have provided philosophical anthropology with a new (post-individualist) point of departure, and at least playfully, to have given some naturalistic grist to Hegel’s proclamation that spirit (Geist) is the truth of nature.
1H, 13C, 15N backbone and IVL methyl group resonance assignment of the fungal β-glucosidase from Trichoderma reesei
Authors: Makraki Eleni , Carneiro Marta G. , Heyam Alex , Eiso A. B. , Siegal Gregg , Hubbard Roderick E.
Published: June 2020

β-glucosidases have received considerable attention due to their essential role in bioethanol production from lignocellulosic biomass. β-glucosidase can hydrolyse cellobiose in cellulose degradation and its low activity has been considered as one of the main limiting steps in the process. Large-scale conversions of cellulose therefore require high enzyme concentration which increases the cost. β-glucosidases with improved activity and thermostability are therefore of great commercial interest. The fungus Trichoderma reseei expresses thermostable cellulolytic enzymes which have been widely studied as attractive targets for industrial applications. Genetically modified β-glucosidases from Trichoderma reseei have been recently commercialised. We have developed an approach in which screening of low molecular weight molecules (fragments) identifies compounds that increase enzyme activity and are currently characterizing fragment-based activators of TrBgl2. A structural analysis of the 55 kDa apo form of TrBgl2 revealed a classical (α/β)8-TIM barrel fold. In the present study we present a partial assignment of backbone chemical shifts, along with those of the Ile (I)-Val (V)-Leu (L) methyl groups of TrBgl2. These data will be used to characterize the interaction of TrBgl2 with the small molecule activators.
Confronting Racism with Mindfulness
Authors: Anālayo Bhikkhu
Published: June 2020

Racial oppression is a longstanding and widespread problem with significant repercussions and consequences for the health of those impacted. The roots of racial prejudice reach far back into the history of European culture. A contribution to the much-needed change can be found in the cultivation of mindfulness, in particular in its external dimension. This emerges from considering the background provided by the early Buddhist dismissal of caste prerogatives in the ancient Indian setting, granting priority to ethical conduct over birth. Besides opening up a new dimension for mindfulness-related research, which has so far predominantly focused on the internal cultivation of mindfulness, exploring the early Buddhist perspective also shows that diversity work can become an integral part of the Buddhist path of practice. This holds in particular for white Buddhists, who need to confront their superiority conceit as an obstruction to their own progress to liberation.
Nowcast models for train delays based on the railway network status
Authors: Thaduri Adithya
Published: June 2020

Switches and crossings (S&C) or turnouts are one of the important systems in the Swedish railway traffic maintenance planning. For immediate diverting of the trains, they need to be predict the working condition for short time duration, also known as nowcasting and for long time duration, also known as forecasting. The prediction of the condition of turnout is useful for traffic planning without disrupting to the traffic. Hence, the main purpose of this paper is to predict the condition of S&Cs for shorter and longer duration. In order to achieve it, at first, statistical analysis is carried out to find the root causes of failures. Secondly, non-homogenous Poisson process is applied to nowcast and forecast the working condition. The results of this study will guide the train dispatchers to plan the train timetable according the present traffic.
Battery pack remanufacturing process up to cell level with sorting and repurposing of battery cells
Authors: Kampker Achim , Wessel Saskia , Fiedler Falko , Maltoni Francesco
Published: June 2020

Traditional remanufacturing is characterized by disassembly of a core up to an optimal depth of disassembly and by the replacement of some parts in order to achieve the specifications and reliability of the original product. Because of the product architecture and the reliability characteristics of electric vehicle batteries, such an approach does not recover the full residual value of battery cells. For batteries, a depth of disassembly up to cell level is necessary, but problematic because of inconvenient battery design features. Hence, an alternative framework will be presented, where each of the battery cells and the battery system key components are considered a core in itself, and the value of a remanufactured battery module depends on the combination of its cells. The product architecture and component requirements will be explained for batteries made of the three most common cell types used in the automotive industry. In addition, three solutions will be presented for the implementation of the proposed framework for remanufacturing regarding both product design and key aspects of the process chain, such as laser cutting and laser welding of battery cells.
IPM-RED: combining higher-order masking with robust error detection
Authors: Keren Osnat , Polian Ilia
Published: June 2020

Cryptographic hardware becomes increasingly vulnerable to physical attacks—both passive side-channel analysis and active fault injections—performed by skillful and well-equipped adversaries. In this paper, we introduce a technique that provides very high security against both types of attacks. It combines inner product masking (IPM), which offers higher-order side-channel attack resistance on word level and on bit level, with nonlinear security-oriented error-detection codes that provide robustness, i.e., strong detection guarantees for arbitrary faults. We prove that our scheme has the same security against side-channel attacks that an earlier, non-robust IPM-based solution has and in addition preserves robustness during addition and multiplication (and therefore arbitrary computations). Moreover, we prove that the information leakage from the checker is small and that the attack will be detected far before the attacker will gain significant information.
Effects of selection and local adaptation on resilience and economic suitability in Apis mellifera carnica
Authors: Kovačić Marin , Puškadija Zlatko , Dražić Marica Maja , Uzunov Aleksandar , Meixner Marina D. , Büchler Ralph
Published: June 2020

Modern techniques of selective breeding show high potential to improve economically important traits of honey bees. However, breeding may neglect fundamental rules of natural selection. The objective of this study was to analyze the effects of selection and local adaptation on some relevant breeding traits of Apis mellifera carnica. We compared open mated queens from three different origins: local Croatian genotypes that are under controlled selection since five generations (MS), a local genotype that was never under selective breeding (NS) and, finally, a non-local genotype from a long-lasting German breeding program (HS). Generally, colonies with queens from breeding programs had better scores for defensive behavior, calmness, and swarming. In contrast, colonies from the NS group showed higher expression of Varroa destructor resistance traits. Although the HS group showed the highest score in most of the behavioral traits, the low overwintering index of colonies from this group after both wintering periods indicated a lack of local adaptation. This research underlines the relevance of breeding activities for the resilience of honey bee populations and the achievement of local adaptation.
Perceptual Decision-Making in Children: Age-Related Differences and EEG Correlates
Authors: Manning Catherine , Wagenmakers Eric-Jan , Norcia Anthony M. , Scerif Gaia , Boehm Udo
Published: June 2020

Children make faster and more accurate decisions about perceptual information as they get older, but it is unclear how different aspects of the decision-making process change with age. Here, we used hierarchical Bayesian diffusion models to decompose performance in a perceptual task into separate processing components, testing age-related differences in model parameters and links to neural data. We collected behavioural and EEG data from 96 6- to 12-year-old children and 20 adults completing a motion discrimination task. We used a component decomposition technique to identify two response-locked EEG components with ramping activity preceding the response in children and adults: one with activity that was maximal over centro-parietal electrodes and one that was maximal over occipital electrodes. Younger children had lower drift rates (reduced sensitivity), wider boundary separation (increased response caution) and longer non-decision times than older children and adults. Yet, model comparisons suggested that the best model of children’s data included age effects only on drift rate and boundary separation (not non-decision time). Next, we extracted the slope of ramping activity in our EEG components and covaried these with drift rate. The slopes of both EEG components related positively to drift rate, but the best model with EEG covariates included only the centro-parietal component. By decomposing performance into distinct components and relating them to neural markers, diffusion models have the potential to identify the reasons why children with developmental conditions perform differently to typically developing children and to uncover processing differences inapparent in the response time and accuracy data alone.
Categories, Balancing, and Fake News: The Jurisprudence of the European Court of Human Rights
Authors: Sardo Alessio
Published: June 2020

Freedom of expression has been often described as a necessary precondition for democracy and for the implementation of an effective system of human rights. A deliberative democracy cannot function if citizens are not granted the fundamental right to express their views and to criticize the government without being censored.1 The rule of law becomes an empty notion if legal orders do not protect the impartial, autonomous judgments of the judiciary.2
FINDING THE BRITISH GOOGLE: RELAXING THE PROHIBITION OF DUAL-CLASS STOCK FROM THE PREMIUM-TIER OF THE LONDON STOCK EXCHANGE
Authors: Reddy Bobby V.
Published: June 2020

There is a dearth of British tech-companies listing on the London Stock Exchange (LSE), and the LSE lacks a large, innovative tech-company such as Google. The UK Government, concerned as to the loss of UK tech-companies to foreign acquirors, views the encouragement of UK tech-firm listings as a policy priority. Dual-class stock, currently prohibited from the LSE Main Market's premium-tier, allows founders to list their firms, and retain majority-control, while holding significantly less of the cash-flow rights in the company. This article will broach the potential for dual-class stock to attract UK tech-company listings, and explore the benefits that dual-class stock can engender for UK tech-companies and their public shareholders. The risks of dual-class structures will also be discussed, but it will be shown that in a UK regulatory context, in relation to high-growth tech-companies, the risks may not be as severe as presumed, and easily moderated through judicious controls.
Peer Idealization and Internal Examples in the Epistemology of Disagreement
Authors: KENYON TIM
Published: June 2020

The epistemology of disagreement has developed around a highly idealized notion of epistemic peers. The analysis of examples in the literature has somewhat entrenched this idealization, when using cases of extant philosophical disputes between named interlocutors. These examples make it hard to emphasize the ordinary ways in which discussants, as disciplinary colleagues, may be wrong. Overlooking these possibilities is probably made easier by widespread attitudes in philosophy about the importance of genius or raw intelligence in doing philosophy. The use of such internal examples needlessly limits consideration of the full range of epistemically relevant features of disagreements.
Causal Powers as Accidents: Thomas Aquinas’s View
Authors: VUCU SIMONA
Published: June 2020

I argue that Thomas Aquinas maintains the view that (created) powers are accidental to their bearers not because powers pertain to bearers with limited essences, but because their bearers have limited actual being. Power tracks not only the essence of something but also its actual existence. Things have powers that are causally relevant when these things exist, that is, the nature of a power is determined by a thing’s essence, but the actual being of the thing of that essence accounts for the limitations of this power and for the extent to which a power can have causal effects.
Study of two species, one new and one known, of the genus Aporcella Andrássy, 2002 (Dorylaimida, Aporcelaimidae) from Iran, with a note on its phylogeny
Authors: Naghavi A. , Niknam G. , Vazifeh N. , Peña-Santiago R.
Published: June 2020

Two species of the genus Aporcella, one new and one previously known, collected from cultivated fields in Iran are studied. Description, morphometrics, illustrations (both line and microphotographs) and D2–D3 sequences are provided for Aporcella talebii sp. n., which is characterized by its 1.66–2.02-mm-long body, lip region offset by constriction and 15–17 μm broad, odontostyle 14–17.5 μm long, neck 412–484 μm long, pharyngeal expansion occupying 46–50% of total neck length, uterus simple and 1.6–2.0 times the corresponding body diameter long, V = 52–59, tail conical (40–50 μm, c = 37–47, c′ = 1.1–1.4) with a weak but perceptible dorsal concavity at the end and male absent. Morphometrics, microphotographs and D2–D3 sequences of Aporcella simplex are also presented, this being its first Asian record. Molecular analyses confirm the monophyly of the genus, its close relationship with other taxa lacking pars refringens vaginae and the polyphyly of Aporcelaimidae.
Effect of the electron redistribution on the nonlinear saturation of Alfvén eigenmodes and the excitation of zonal flows
Authors: Biancalani A. , Bottino A. , Lauber P. , Mishchenko A. , Vannini F.
Published: June 2020

Numerical simulations of Alfvén modes driven by energetic particles are performed with the gyrokinetic (GK) global particle-in-cell code ORB5. A reversed shear equilibrium magnetic field is adopted. A simplified configuration with circular flux surfaces and large aspect ratio is considered. The nonlinear saturation of beta-induced Alfvén eigenmodes (BAE) is investigated. The roles of the wave–particle nonlinearity of the different species, i.e. thermal ions, electrons and energetic ions are described, in particular for their role in the saturation of the BAE and the generation of zonal flows. The nonlinear redistribution of the electron population is found to be important in increasing the BAE saturation level and the zonal flow amplitude.
Scale-free architectures support representational diversity
Authors: Fields Chris , Glazebrook James F.
Published: June 2020

Gilead et al. propose an ontology of abstract representations based on folk-psychological conceptions of cognitive architecture. There is, however, no evidence that the experience of cognition reveals the architecture of cognition. Scale-free architectural models propose that cognition has the same computational architecture from sub-cellular to whole-organism scales. This scale-free architecture supports representations with diverse functions and levels of abstraction.
A modern materialist approach to abstraction, concreteness, and explanation in cognition
Authors: Shillcock Richard
Published: June 2020

Although endorsing the authors’ concentration on the issue of abstraction, I critique (a) the philosophical nature of their abstract–concrete dimension, (b) their view of the brain–world barrier, and (c) their implicit positivist one-way hierarchy that has abstraction as the goal.
Successful simulation requires bridging levels of abstraction
Authors: Zhao Zidong , Mildner Judith N. , Tamir Diana I.
Published: June 2020

Although many simulations draw upon only one level of abstraction, the process for generating rich simulations requires a dynamic interplay between abstract and concrete knowledge. A complete model of simulation must account for a mind and brain that can bridge the perceptual with the conceptual, the episodic with the semantic, and the concrete with the abstract.
Simulation across representation: The interplay of schemas and simulation-based inference on different levels of abstraction
Authors: Schilling Malte , Chang Nancy , Rohlfing Katharina J. , Spranger Michael
Published: June 2020

Language comprehension of action verbs recruits embodied representations in the brain that are assumed to invoke a mental simulation (e.g., “grasping a peanut”). This extends to abstract concepts, as well (“grasping an idea”). We, therefore, argue that mental simulation works across levels of abstractness and involves higher-level schematic structures that subsume a generic structure of actions and events.
Is it always so? Unexpected visions
Authors: Deręgowski Jan B. , Tatler Benjamin W.
Published: June 2020

If we consider perceptions as arising from predictive processes, we must consider the manner in which the underlying expectations are formed and how they are applied to the sensory data. We provide examples of cases where expectations give rise to unexpected and unlikely perceptions of the world. These examples may help define bounds for the notion that perceptual hypotheses are direct derivatives of experience and are used to furnish sensible interpretations of sensory data.
SPECIFICATION TESTING FOR ERRORS-IN-VARIABLES MODELS
Authors: Otsu Taisuke , Taylor Luke
Published: June 2020

This paper considers specification testing for regression models with errors-in-variables and proposes a test statistic comparing the distance between the parametric and nonparametric fits based on deconvolution techniques. In contrast to the methods proposed by Hall and Ma (2007, Annals of Statistics, 35, 2620–2638) and Song (2008, Journal of Multivariate Analysis, 99, 2406–2443), our test allows general nonlinear regression models and possesses complementary local power properties. We establish the asymptotic properties of our test statistic for the ordinary and supersmooth measurement error densities. Simulation results endorse our theoretical findings: our test has advantages in detecting high-frequency alternatives and dominates the existing tests under certain specifications.
Electron Beam Damage of Biomolecules Assessed by Energy Loss
Spectroscopy
Authors: Isaacson M. , Collins M.L. , Listvan M.
Published: June 2020

Over the past five years it has become evident that radiation damage
provides the fundamental limit to the study of blomolecular structure by
electron microscopy. In some special cases structural determinations at very
low doses can be achieved through superposition techniques to study periodic
(Unwin & Henderson, 1975) and nonperiodic (Saxton & Frank, 1977)
specimens. In addition, protection methods such as glucose embedding (Unwin
& Henderson, 1975) and maintenance of specimen hydration at low
temperatures (Taylor & Glaeser, 1976) have also shown promise. Despite
these successes, the basic nature of radiation damage in the electron
microscope is far from clear. In general we cannot predict exactly how
different structures will behave during electron Irradiation at high dose
rates. Moreover, with the rapid rise of analytical electron microscopy over
the last few years, nvicroscopists are becoming concerned with questions of
compositional as well as structural integrity. It is important to measure
changes in elemental composition arising from atom migration in or loss from
the specimen as a result of electron bombardment.
Reconstruction of Non-periodic Objects using Correlation Methods
Authors: Frank J.
Published: June 2020

The first reconstructions of low-dose nonperiodic objects using computer correlation and averaging have now been achieved (Frank et al., 1978a, b). Previous papers have outlined the methods (Frank, 1975, 1976, 1978) and demonstrated the feasibility of this approach when applied to low-dose electron micrographs (Saxton and Frank, 1977), This report is the first attempt to summarize the experience gained in the experiments. Detailed descriptions of glutamine synthetase reconstructions from both high-dose and low-dose electron micrographs (in collaboration with M. Kessel, W. Goldfarb, D. Eisenberg, and T. S. Baker) are in preparation.
Applications of Lattice Fringe Imaging
Authors: Sinclair R.
Published: June 2020

The observation of closely-spaced lattice fringes is the common test for
assessing the resolution of a transmission electron microscope. The
capability regularly achieved by new instruments is 2.0 Å, although much
finer spaclngs are often attained without inordinate difficulty. This opens
up the possibility of examining materials at atomic plane level. In the
present article the areas of application of this technique are
outlined.

Lattice fringe imaging has evolved in a cautious manner. The main
difficulty is associated with how to relate the fringes to the positions of
the diffracting atomic planes in the specimen. As pointed out by Hirsch et
al. (1965) a simple correlation is generally not possible. In addition the
spacing and direction of the fringes may deviate from the crystal lattice
spacing and orientation when images are taken away from the exact Bragg
condition (Hirsch et al., 1965). For a dislocated crystal the situation may
be worse, with asymmetric fringe distortions on either side of a terminating
fringe, or multiple terminating fringes representing a single dislocation
(Cockayne, Parsons and Hoelke, 1971).
Superconducting Lenses
Authors: Dietrich Isolde
Published: June 2020

In the beginning of the sixties the construction of superconducting lenses started out accompanied by enthusiastic prognostications / Fernandez Moran (1965), Laberrigue et al (1964)_7. Regarding more or less theoretical aspects some doubts have arisen in the last years concerning any real advantages in superconducting electron optic devices J_ Bon jour (1976)_7. I think, however, one is now able to prove with facts that superconducting lenses are going to be powerful instruments in electron microscopy. Examples for the possibilities are given in the micrographs (Fig. 9-13) taken with a superconducting lens system. Figure 13d, e.g. demonstrates that mercury atoms arranged hexagonally with a distance of O.36 nm can be clearly distinguished.
Approximations in the Dynamical Theory of Electron Diffract
Authors: Sheinin S.S.
Published: June 2020

The last twenty years have seen a remarkable development in electron
microscopy of crystalline materials. This development has, quite naturally,
been stimulated by the continuing quest of the electron microscopist for
more information about the structure of his specimens and it is not
surprising, therefore, that the more qualitative observations of the past
have been supplemented by techniques which permit higher resolution, more
quantitative information to be extracted. The fundamental role played by the
dynamical theory of electron diffraction in this development requires no
emphasis on my part. As is true with all physical theories, however, the
dynamical theory itself has been the subject of continued development and
investigation. This work is not simply of academic interest but has been an
important, and in fact necessary, concomitant of the developments in the
electron microscopy of crystals referred to above. The reason for this can
be easily understood when it is recalled that the form of the dynamical
theory used in image contrast calculations has many approximations embodied
in it.
Electron Energy Loss Spectroscopy in the Electron Microscope: Present
State of Affairs
Authors: Colliex C. , Trebbia P.
Published: June 2020

In the transmission electron microscope, among the various signals
resulting from the interaction between the primary electron beam of well
defined energy E0 and the specimen, the energy spectral distribution in the
transmitted beam contains useful additional informations concerning the
physical or chemical properties of the sample. As a consequence the
insertion of a proper energy filtering device on any existing microscope
column opens new fields of investigation from the fundamental understanding
of the image formation mechanisms or the determination of the excitations
spectrum in a solid to the development of a localized microanalytical
technique at the spatially resolved scale of the electron
microscope.
In Situ Deformation by High Voltage Electron Microscopy
Authors: Fujita H.
Published: June 2020

It is well known that materials are structure-sensitive. This means that
properties of materials, especially mechanical properties, are determined by
behavior of the lattice imperfections such as dislocations and point
defects. High resolution and quick recording of the images by electron
microscopy have been effectively used for studying behavior of lattice
imperfections. It is very difficult, however, to get a definite conclusion
about the deformation processes based on the static electron microscope
observation of the dislocation structures formed by deformation, because
many processes can be considered to get the same dislocation structure.
Therefore, dynamic study of the behavior of lattice imperfections is
necessary to carry out in order to investigate the properties of
materials.
Advances in Semiconductor Applications of Electron Microscopy
Authors: Saparin G.V.
Published: June 2020

Semiconductors occupy the special place among materials which are
investigated by electron microscopy. This situation is determined by the
specific physical properties which they have such as electron-holo
conductivity, wide range of resistivity at room temperature
(10-3.om.cm -
106om.cm),thermoand photo EMP, eldctron-hole
recombination, carriers mobility, Hall effect, existance of the electrical
dipole layers etc. All main semiconductor properties are explained by the
low ( < 10 eV) forbidden gap in the energetical model of semiconductors.
Naturally, the electron-semiconductor interaction has its own pecularities
and differs from electron-metal interactions.
Introduction to Cell Membranes at Molecular Resolution
Authors: Barrnett R.J.
Published: June 2020

This subject, is like observing the panorama of a mountain range,
magnificent towering peaks, but it doesn't take much duration of observation
to recognize that they are still in the process of formation. The mountains
consist of approaches, materials and methods and the rocky substance of
information has accumulated to such a degree that I find myself
concentrating on the foothills in the foreground in order to keep up with
the advance; the edifices behind form a wonderous, substantive background.
It's a short history for such an accumulation and much of it has been moved
by the members of the societies that make up this International
Federation.

My panel of speakers are here to provide what we hope is an interesting
scientific fare, based on the fact that there is a continuum of biological
organization from biochemical molecules through macromolecular assemblies
and cellular membranes to the cell itself. Indeed, this fact explains the
whole range of towering peaks that have emerged progressively during the
past 25 years.
Introduction
Authors: Bernard W.
Published: June 2020

In comparison to many other fields of ultrastructural research in Cell
Biology, the successful exploration of genes and gene activity with the
electron microscope in higher organisms is a late conquest. Nucleic acid
molecules of Prokaryotes could be successfully visualized already since the
early sixties, thanks to the Kleinschmidt spreading technique - and much
basic information was obtained concerning the shape, length, molecular
weight of viral, mitochondrial and chloroplast nucleic acid. Later,
additonal methods revealed denaturation profiles, distinction between single
and double strandedness and the use of heteroduplexes-led to gene mapping of
relatively simple systems carried out in close connection with other methods
of molecular genetics.
Computer-Assisted Analysis and Display of Nuclear Structures
Authors: Moens P.B.
Published: June 2020

Quantitative electron microscopy of cells, organelles, or chromosomes
gives information on the numbers, sizes, distribution and organization of
the structures in question. In the case of the nucleus, quantitative
information can be obtained on nuclear pores, spindle pole bodies,
kinetochores, centromeres, microtubules, chromosomes, synaptonemal
complexes, and nucleoli. Scanning electron microscopy of fractured specimens
and transmission electron microscopy of spread preparations and high voltage
TKM can give some of the information, but total information can best be
obtained from a complete series of sections of the material. The analysis of
photographic records, however, is cumbersome and the relevant information is
often not readily visible. In this report some of the methods ia compiling
quantitative information on the nucleus and its components are
described.
Recent Improvements to the Em-7 at the Madison Biotechnology
Resource
Authors: Pawley James
Published: June 2020

There are only two HVEM installations in the U.S. which service
biological investigators in the country at large. This paper will describe
recent or planned improvements in the reliability, user convenience, and
high resolution capabilities of the AEI, EM-7 at the Madison NIH
Biotechnology Resource with the idea that feedback from prospective users
can guide and support this continuing program.
Electron Diffraction of Platinum Labelled Bacteriorhodopsin
Authors: Dumont M. E. , Wiggins J. W. , Hayward S. B.
Published: June 2020

We are using electron diffraction to characterize a platinum-containing
derivative of bacteriorhodopsin, the light-driven proton pump from
Halobacterium halobium. This has been undertaken with the dual aims of:
1)using the method of multiple heavy atom isomorphous replacement to obtain
high resolution structural information about the protein, and 2)locating
heavy atom labelled amino acids in the structure in order to correlate the
recently determined sequence with the structural map. A necessary first step
in such studies is the location of the heavy atoms in the low resolution
structure. This report focusses on ways of dealing with the inherent
statistical uncertainties encountered in this heavy atom
localization.
Further Uses of Color in Scanning Transmission Electron
Microscopy
Authors: Crewe A. V. , Kopf D. , Ohtsuki M. , Usala P.
Published: June 2020

We have recently shown several examples of the use of intensity-to-color
mapping on order to increase the visibility of features in STEM micrographs
(1,2). These conversions were implemented on a commercial black and white to
color converter operating on standard television video signals (3). Color
enhancement in this fashion is useful in following the motion of heavy atom
species of dissimilar atomic number in time-lapse movies, to enhance
rotational or staining symmetries in biological molecules or polymers, or to
correlate equal intensity features across the field of view of a
micrograph.
Observation of Biological Specimens Using Dark Field STEM
Authors: Kokubo Y. , Inoue M. , Hosoi J. , Johansen B. V.
Published: June 2020

Unstained biological specimens were observed in the dark field STEM mode
using a JEM-100CX TEMSCAN equipped with an annular type dark field detector.
It was confirmed, by comparing the micrographs obtained in the above mode
with micrographs obtained in the dark field CTEM mode, that the former were
superior in regard to observable detail.

In electron microscopy, it is a well known fact that the observation of
unstained biological specimens consisting of light elements such as carbon,
nitrogen, oxygen, etc., is extremely difficult due to the small scattering
factor involved. In general, although negative or positive staining by heavy
metallic elements is feasible for such specimens, the possibility of
structural, morphological and chemistry related (e.g., bonding) degradation,
as a result of such staining, is always present. Accordingly, freeze etching
and freeze sectioning, in spite of the complicated preparation procedure
involved, are becoming quite popular in that a specimen so treated, becomes
highly resistant to degradation resultant upon staining. A further popular
means for surmounting the above problems relating to specimen degradation,
poor contrast, etc. is the so-called “dark field method”, the salient
feature of which is that it is simple to utilize and dispenses with the
problems involved in the freeze etching and freeze sectioning techniques.
The main reason why dark field STEM is more effective than dark field CTEM
is that, in the case of former, there are no lenses below the specimen, thus
permitting thicker specimens to be observed without having to take into
consideration lens chromatic aberration caused by inelastic scattering.
Another reason Is that increased space availability allows a large angle
acceptance detector to be used, thereby enhancing the collection
efficiency1) of the elastically scattered electrons
which in turn ensures a high contrast image and low-dose specimen
observation.
Methods for Displaying Defocus and Astigmatism of High Resolution Stem
Images
Authors: Krakow William
Published: June 2020

Focussing and stigmation of the objective lens for high resolution STEM
imaging is usually achieved by repeated reduced area scans of a given
specimen area under manual control of the instrument. This method is
particularly laborious since the scan times for images can be upwards of
several seconds which subjects a specimen to unwanted electron beam
exposure.

Methods have been proposed to optimize STEM images such as the use of
shadow images1 where a fixed beam pattern for a highly
defocussed objective lens is observed. This method again requires a high
beam dose in a given specimen area. Alternately, if a white noise object
such as a carbon film is used, granular image features without any
directionality are desired. In this case the eye must integrate over a large
number of small image features. A better alternative is the use computer
control to digitize images in real time and compute the power spectrum of an
image could be employed. This would require a dedicated high speed computer
system for a 1000 × 1000 display, but this latter method would have the
advantage that only a single scan of image is required.
Low Acceleration Scanning Electron Microscope
Authors: Todokoro H. , Fukuhara S. , Sakitani Y.
Published: June 2020

A low acceleration scanning electron microscope ( LASEM ) offers several
advantages:

no charging effects

low radiation damage

high yield for secondary electron emission

high sensitivity for surface topography

The application of a low acceleration microscope, however, has been
limited to special purposes because of its poor resolution. A high
resolution LASEM has been developed and is shown in Fig.1. The microscope
uses a new electron gun with a field emission cathode. The gun 1,000 times
brighter than a conventional thermionic cathode. The relation between
brightness and resolution of a SEM for 1 kV acceleration voltage is shown in
Fig.2. The three regions in the figure correspond to tungsten thermionic,
LaB6 thermionic and field emission guns. Resolution is approximately 1 μm in
the case of the tungsten thermionic gun at 1 kV, while resolution is 200 A
in the new microscope equipped with a field emission gun.
Advantages of a Field Emission Gun for a Combined Analytical and High
Resolution Transmission Electron Microscope
Authors: Bentley J.
Published: June 2020

This paper describes the various areas of analytical and high resolution
microscopy which can be greatly improved by the use of a high-brightness
field emission gun (FEG). The instrument used was a Philips EM400T equipped
with a FEG, 6585 STEM unit, EDAX EDS detector and Kevex 5100 spectrometer.
The <111> oriented W tip was supplied by the manufacturer.

The brightness β (current density per unit solid angle) normalized to
the ac-celeratiang voltage, V0 is defined by β =
4I/πd2α2jV0,
where I is the current in a probe of diameter d and divergence
αi. Results are presented in Table 1 for three
typical operating conditions. Probe currents >10−7 A
have been obtained in the TEM mode which is sufficient for work at medium
magnifications (20 to 100 K). Probe currents were measured from the screen
current/exposure time system which had been calibrated with a purpose built
Faraday cup. Probe diameters in TEM were measured from high magnification
TEM images and in STEM by imaging the STEM raster in the TEM mode. This is
possible because of the symmetric objective lens which can operate at the
same excitation in TEM and STEM. An example is shown in Fig. 1. The values
in Table 1 should be compared to conventional W hairpin sources for which β
≅ 1.
Applications of STEM to Problems in Materials Science
Authors: Vander Sande John B. , Garratt-Reed Anthony J.
Published: June 2020

The scanning transmission electron microscope (STEM) concept developed
gradually as attempts were made to combine the advantages and eliminate the
disadvantages of the transmission electron microscope, the scanning electron
microscope, and the electron microprobe. However, the marketing of the first
commercial dedicated STEM (the VG Microscopes HB5) spurred the development
of the instrumentation and the understanding of the data interpretation
required for full utilization of the technique. Today, while some avenues
remain incompletely developed, the STEM is accepted as a powerful research
tool, and the prospect of being able to study the products of the
interaction of a very fine electron beam with a specimen has provoked
workers to perform imaginative and informative experiments. Below are
presented a few recent samples of the applications of such a STEM, in the
authors’ laboratory, to problems in the field of materials science.
The Influence of Diffracting Conditions on Quantitative Electron Energy
Loss Spectroscopy
Authors: Zaluzec N. J. , Hren J. , Carpenter R. W.
Published: June 2020

Since many applications of electron energy loss spectroscopy (EELS) deal
with microanalysis of crystalline materials it is relevant to consider the
effects of diffracting conditions on an EELS measurement. It is well known
that anamolous effects can be observed during thin film x-ray microanalysis
when crystalline materials are oriented under diffracting conditions near S
= 0.1-4 It is not surprizing, therefore, that similar
effects will be present in EELS, since this anamolous x-ray generation is a
result of variations in the ionization cross-section with crystalline
orientation2,3. Furthermore since multiple
scattering effects quickly average out these
perturbations2 one expects the most pronounced
effects under conditions appropriate to EELS.5
Plasmon Scattering Intensity in Small Aluminum Spheres
Authors: Batson P. E.
Published: June 2020

It has generally been assumed that a relative thickness determination in
thin samples can be made by observing the variation of the bulk plasmon
scattering intensity. This method, of course, relies on the assumption that
the plasmon scattering varies with the
thickness,1

Here Ip is the plasmon intensity,
I0 is the incident beam intensity, λ is the total
scattering mean free path, t is the sample thickness, and ɛ is the bulk
dielectric constant for the material being probed. It can be
shown1 that the unscattered beam intensity is just
, and therefore a simple
ratio of the plasmon intensity to the unscattered beam intensity would seem
to give t, provided ʵ is known. It has been shown by
Ritchie2, however, that for thin films two more
terms occur in addition to that shown in (1). He found for the scattered
intensity,

where f and g arc some functions periodic in the thickness t. The third
term here is the normal surface plasmon scattering. The second is a surface
interference term at the bulk plasmon energy and is a manifestation of a
spatial quantization of the bulk plasmon in the direction perpendicular to
the film surfaces. (2) can be evaluated at the plasmon frequency
ωp,
An Automated System for Energy-Loss Microanalysis
Authors: Egerton R. F.
Published: June 2020

Figure 1 shows a system which we are using for storage and display of
electron energy-loss spectra, based on a Tracor Northern TN-1710
multichannel analyser. For serial acquisition, scan coils of the magnetic
spectrometer1 are driven directly from the ramp
output of the multichannel analyser. The electron detector consists of a
transmission phosphor followed by a photo-multiplier tube, whose analogue
output is fed via a 5 MHz voltage-to-frequency converter (Teledyne model
4707) into a TN-1710-26 plug-in scaling module. To allow adequate dynamic
range (>108) and avoid overloading the
photomultiplier tube, PMT gain is changed by a factor G ˜ 500 during
acquisition. This is done automatically by incorporating into the line from
the power supply (Venus model LR-2N) a series of Zener diodes which are
short-circuited by a reed relay (driven from a high-gain amplifier) when the
scan voltage exceeds a preset threshold (fig. 2). The gain change is
accomplished in a shorter time (a few ms) than was possible by
voltage-programming the power supply, which makes the factor G easier to
measure accurately.