scholarly journals Force Microscopy – A Tool to Elucidate the Relationship Between Nanomechanics and Function in Viruses

10.5772/36054 ◽  
2012 ◽  
Author(s):  
J.L. Cullar ◽  
E. Donath
Keyword(s):  
Force Microscopy ◽  
And Function ◽  
The Relationship

Depth dependent osmotic and swelling properties of cartilage

2012 ◽  
Vol 1418 ◽  
Author(s):  
Candida Silva ◽  
Iren Horkayne-Szakaly ◽  
Preethi Chandran ◽  
Emilios K. Dimitriadis ◽  
David Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Articular Surface ◽  
Swelling Pressure ◽  
Osmotic Swelling ◽  
Swelling Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Joint Surfaces ◽  
And Function ◽  
The Relationship

ABSTRACTArticular cartilage is a low-friction, load-bearing tissue located at joint surfaces. It experiences static and dynamic forces including shear, compression and tension. We investigate the relationship between structure and function by measuring the osmotic and mechanical properties in cartilage layers as a function of the distance from the articular surface. Atomic force microscopy is used to probe the mechanical properties at high spatial resolution. The mechanical measurements are complemented by osmotic swelling pressure observations made on the same samples using a novel tissue osmometer. The results show that the osmotic modulus significantly depends on the distance from the articular surface. Its value is highest in the deep zone and lowest in the middle zone.

The Relationship between Nanoscale Architecture and Function in Photovoltaic Multichromophoric Arrays as Visualized by Kelvin Probe Force Microscopy

2008 ◽  
Vol 130 (44) ◽  
pp. 14605-14614 ◽  
Author(s):  
Vincenzo Palermo ◽  
Matthijs B. J. Otten ◽  
Andrea Liscio ◽  
Erik Schwartz ◽  
Pieter A. J. de Witte ◽  
...  
Keyword(s):  
Kelvin Probe Force Microscopy ◽  
Kelvin Probe ◽  
Force Microscopy ◽  
And Function ◽  
The Relationship

Scanning tunneling microscopy (STM) of DNA and RNA

1989 ◽  
Vol 47 ◽  
pp. 34-35
Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans
Keyword(s):  
Molecular Structures ◽  
Inorganic Materials ◽  
Resolving Power ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Form And Function ◽  
Dna And Rna ◽  
Calf Thymus ◽  
And Function ◽  
The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

Physicianship and the Rebirth of Medical Education

2018 ◽  
Author(s):  
J. Donald Boudreau ◽  
Eric Cassell ◽  
Abraham Fuks
Keyword(s):  
Medical Education ◽  
Educational Process ◽  
Medical Attention ◽  
Patient Centeredness ◽  
Goals Of Medicine ◽  
The Subject ◽  
Definition Of ◽  
And Function ◽  
William Osler ◽  
The Relationship

This book reimagines medical education and reconstructs its design. It originates from a reappraisal of the goals of medicine and the nature of the relationship between doctor and patient. The educational blueprint outlined is called the “Physicianship Curriculum” and rests on two linchpins. First is a new definition of sickness: Patients know themselves to be ill when they cannot pursue their purposes and goals in life because of impairments in functioning. This perspective represents a bulwark against medical attention shifting from patients to diseases. The curriculum teaches about patients as functional persons, from their anatomy to their social selves, starting in the first days of the educational program and continuing throughout. Their teaching also rests on the rock-solid grounding of medicine in the sciences and scientific understandings of disease and function. The illness definition and knowledge base together create a foundation for authentic patient-centeredness. Second, the training of physicians depends on and culminates in development of a unique professional identity. This is grounded in the historical evolution of the profession, reaching back to Hippocrates. It leads to reformulation of the educational process as clinical apprenticeships and moral mentorships. “Rebirth” in the title suggests that critical ingredients of medical education have previously been articulated. The book argues that the apprenticeship model, as experienced, enriched, taught, and exemplified by William Osler, constitutes a time-honored foundation. Osler’s “natural method of teaching the subject of medicine” is a precursor to the Physicianship Curriculum.

scholarly journals Ultrafine metal-polymer catalysts based on polyconjugated systems for Fisher–Tropsch synthesis

2020 ◽  
Vol 92 (6) ◽  
pp. 977-984
Author(s):  
Mayya V. Kulikova ◽  
Albert B. Kulikov ◽  
Alexey E. Kuz’min ◽  
Anton L. Maximov
Keyword(s):  
Tropsch Synthesis ◽  
X Ray Diffraction ◽  
Fischer Tropsch ◽  
Force Microscopy ◽  
Composite Catalysts ◽  
Fe Catalyst ◽  
Atomic Force ◽  
And Function ◽  
Metal Polymer

AbstractFor previously studied Fischer–Tropsch nanosized Fe catalyst slurries, polymer compounds with or without polyconjugating structures are used as precursors to form the catalyst nanomatrix in situ, and several catalytic experiments and X-ray diffraction and atomic force microscopy measurements are performed. The important and different roles of the paraffin molecules in the slurry medium in the formation and function of composite catalysts with the two types of aforementioned polymer matrices are revealed. In the case of the polyconjugated polymers, the alkanes in the medium are “weakly” coordinated with the metal-polymer composites, which does not affect the effectiveness of the polyconjugated polymers. Otherwise, alkane molecules form a “tight” surface layer around the composite particles, which create transport complications for the reagents and products of Fischer-Tropsch synthesis and, in some cases, can change the course of the in situ catalyst formation.

From self-evident norms to contingent couplings: A systems-theoretical analysis of changes in the relationship between schools and the function systems in Denmark

2021 ◽  
pp. 147490412110097
Author(s):  
Niels Åkerstrøm Andersen ◽  
Justine Grønbæk Pors
Keyword(s):  
Theoretical Analysis ◽  
Education System ◽  
Teaching Profession ◽  
School Governance ◽  
World Society ◽  
Historical Account ◽  
And Function ◽  
The Relationship ◽  
Point Of Departure

Taking a point of departure in the paradoxical fact that the increase in educational knowledge leads to an increase in uncertainty for educational organisations, this article explores how uncertainty and contingency have increasingly become an integral part of school governance. The article draws on Niklas Luhmann’s theory of ‘World Society’ as a functional differentiated society providing a range of different symbolic media for educational organisations. To trace the increase in the complexity of governing, we provide a historical account of the shifting couplings between schools and function systems. We show how the school becomes linked to an increasing number of symbolic media so that education becomes only one out of many other concerns. The article studies the consequences these shifting couplings have for how schools are governed and how they are expected to self-manage their relationship to different function systems. The article adds to existing studies of how education has become more and more differentiated with the argument that this has also led to new forms of couplings between schools and the education system with a number of important implications for the teaching profession.

scholarly journals Lung ultrasound presentation of COVID-19 patients: phenotypes and correlations

2021 ◽  
Author(s):  
Gianmarco Secco ◽  
◽  
Marzia Delorenzo ◽  
Francesco Salinaro ◽  
Caterina Zattera ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Lung Ultrasound ◽  
Structure And Function ◽  
General Ward ◽  
Prognostic Role ◽  
Interstitial Syndrome ◽  
Lung Structure ◽  
And Function ◽  
The Relationship

AbstractBedside lung ultrasound (LUS) can play a role in the setting of the SarsCoV2 pneumonia pandemic. To evaluate the clinical and LUS features of COVID-19 in the ED and their potential prognostic role, a cohort of laboratory-confirmed COVID-19 patients underwent LUS upon admission in the ED. LUS score was derived from 12 fields. A prevalent LUS pattern was assigned depending on the presence of interstitial syndrome only (Interstitial Pattern), or evidence of subpleural consolidations in at least two fields (Consolidation Pattern). The endpoint was 30-day mortality. The relationship between hemogasanalysis parameters and LUS score was also evaluated. Out of 312 patients, only 36 (11.5%) did not present lung involvment, as defined by LUS score < 1. The majority of patients were admitted either in a general ward (53.8%) or in intensive care unit (9.6%), whereas 106 patients (33.9%) were discharged from the ED. In-hospital mortality was 25.3%, and 30-day survival was 67.6%. A LUS score > 13 had a 77.2% sensitivity and a 71.5% specificity (AUC 0.814; p < 0.001) in predicting mortality. LUS alterations were more frequent (64%) in the posterior lower fields. LUS score was related with P/F (R2 0.68; p < 0.0001) and P/F at FiO2 = 21% (R2 0.59; p < 0.0001). The correlation between LUS score and P/F was not influenced by the prevalent ultrasound pattern. LUS represents an effective tool in both defining diagnosis and stratifying prognosis of COVID-19 pneumonia. The correlation between LUS and hemogasanalysis parameters underscores its role in evaluating lung structure and function.

scholarly journals RELATION OF ADRENAL CORTICAL HORMONE TO LYMPHOID TISSUE AND LYMPHOCYTES

Blood ◽  
1948 ◽  
Vol 3 (7) ◽  
pp. 729-754 ◽  
Author(s):  
WILLIAM N. VALENTINE ◽  
CHARLES G. CRADDOCK ◽  
JOHN S. LAWRENCE
Keyword(s):  
Adrenal Cortex ◽  
Lymphoid Tissue ◽  
Hormonal Control ◽  
Tissue Structure ◽  
Lymphoid Tissues ◽  
Adrenal Cortical Hormone ◽  
Cortical System ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

Abstract The hormonal control through the hypophyseo-adrenal cortical system of lymphoid tissue structure and function is an important concept. We cannot at the present time regard that the concept is established fact. Final judgment must await additional work and the clarification of some of the inconsistencies which appear to exist. It seems reasonable that lymphoid tissue is one of the end organs of adrenal cortical hormone and that it may perhaps play a role in the response of the organism to stress. It seems quite clear that the sugar hormone of the adrenal cortex is capable of producing structural alterations in lymphoid tissue. Change in thoracic duct lymphocyte numbers as a result of augmentation in the amount of available adrenal cortical hormone is at present controversial. Experiments in this laboratory have failed to demonstrate it. The production of lymphopenia, at least in some species and possibly in man, by increasing available sugar hormone is supported by some evidence. The exact mechanism of production of lymphopenia is open to question, its relationship to changes in lymphoid tissue structure being one of inference. The converse situation—absolute lympocytosis resulting from deprivation of adrenal cortical hormone—is the subject of controversial reports. At best, it must be admitted that relatively slight alterations from the accepted normal range of lymphocyte values occur in the adrenal insufficient organism. Changes in plasma gamma globulins and antibody titers associated with changes in the amount of available cortical hormone are reported. It should be clarified whether such changes have necessarily resulted from lymphocyte dissolution or are related to other of the variegated actions of adrenal cortical hormone. The relationship of adrenal cortical hormone to lymphoid tissue and lymphocytes and the relationship of the latter to the response of the organism to stress must indeed be complex. It is reasonably well established that the life span of the lymphocyte is very short indeed1,58,22 and each lymphocyte presumably liberates its metabolically important contents within a few hours at the most. If stress continues for any period of time, as often it does, it is difficult to visualize the wisdom of interfering with the production of metabolically vital substances in order to secure the transient benefits of lymphoid tissue dissolution. It is also somewhat difficult to regard as proved that the various changes reported after hormone augmentation or deprivation necessarily represent the normal mechanism by which these factors are regulated and kept within physiologic limits. More investigations are required to answer such questions and to further elucidate the interrelationship of the adrenal cortex and lymphoid tissues.

scholarly journals Validating Linear Systems Analysis for Laminar fMRI: Temporal Additivity for Stimulus Duration Manipulations

2020 ◽  
Author(s):  
Jelle A. van Dijk ◽  
Alessio Fracasso ◽  
Natalia Petridou ◽  
Serge O. Dumoulin
Keyword(s):  
Systems Theory ◽  
Linear Systems ◽  
Blood Oxygenation ◽  
Ultra High Field ◽  
Feedback Information ◽  
Oxygenation Level ◽  
Early Visual Cortex ◽  
Magnetic Resonance Imaging Mri ◽  
And Function ◽  
The Relationship

AbstractAdvancements in ultra-high field (7 T and higher) magnetic resonance imaging (MRI) scanners have made it possible to investigate both the structure and function of the human brain at a sub-millimeter scale. As neuronal feedforward and feedback information arrives in different layers, sub-millimeter functional MRI has the potential to uncover information processing between cortical micro-circuits across cortical depth, i.e. laminar fMRI. For nearly all conventional fMRI analyses, the main assumption is that the relationship between local neuronal activity and the blood oxygenation level dependent (BOLD) signal adheres to the principles of linear systems theory. For laminar fMRI, however, directional blood pooling across cortical depth stemming from the anatomy of the cortical vasculature, potentially violates these linear system assumptions, thereby complicating analysis and interpretation. Here we assess whether the temporal additivity requirement of linear systems theory holds for laminar fMRI. We measured responses elicited by viewing stimuli presented for different durations and evaluated how well the responses to shorter durations predicted those elicited by longer durations. We find that BOLD response predictions are consistently good predictors for observed responses, across all cortical depths, and in all measured visual field maps (V1, V2, and V3). Our results suggest that the temporal additivity assumption for linear systems theory holds for laminar fMRI. We thus show that the temporal additivity assumption holds across cortical depth for sub-millimeter gradient-echo BOLD fMRI in early visual cortex.

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