scholarly journals Connecting Structure–Property and Structure–Function Relationships across the Disciplines of Chemistry and Biology: Exploring Student Perceptions

2018 ◽  
Vol 17 (2) ◽  
pp. ar33 ◽  
Author(s):  
Kathryn P. Kohn ◽  
Sonia M. Underwood ◽  
Melanie M. Cooper

While many university students take science courses in multiple disciplines, little is known about how they perceive common concepts from different disciplinary perspectives. Structure–property and structure–function relationships have long been considered important explanatory concepts in the disciplines of chemistry and biology, respectively. Fourteen university students concurrently enrolled in introductory chemistry and biology courses were interviewed to explore their perceptions regarding 1) the meaning of structure, properties, and function; 2) the presentation of these concepts in their courses; and 3) how these concepts might be related. Findings suggest that the concepts of structure and properties were interpreted similarly between chemistry and biology, but students more closely associated the discussion of structure–property relationships with their chemistry courses and structure–function with biology. Despite receiving little in the way of instructional support, nine students proposed a coherent conceptual relationship, indicating that structure determines properties, which determine function. Furthermore, students described ways in which they connected and benefited from their understanding. Though many students are prepared to make these connections, we would encourage instructors to engage in cross-disciplinary conversations to understand the shared goals and disciplinary distinctions regarding these important concepts in an effort to better support students unable to construct these connections for themselves.

2019 ◽  
Vol 10 (23) ◽  
pp. 2952-2959 ◽  
Author(s):  
Nathan A. Carter ◽  
Tijana Z. Grove

In the past two decades researchers have shown great interest in mimicking biological structures and their complex structure–property relationships. Herein we highlight examples of hydrogels and bioelectronic materials that illustrate the rational design of material properties and function.


Author(s):  
J. Petermann ◽  
G. Broza ◽  
U. Rieck ◽  
A. Jaballah ◽  
A. Kawaguchi

Oriented overgrowth of polymer materials onto ionic crystals is well known and recently it was demonstrated that this epitaxial crystallisation can also occur in polymer/polymer systems, under certain conditions. The morphologies and the resulting physical properties of such systems will be presented, especially the influence of epitaxial interfaces on the adhesion of polymer laminates and the mechanical properties of epitaxially crystallized sandwiched layers.Materials used were polyethylene, PE, Lupolen 6021 DX (HDPE) and 1810 D (LDPE) from BASF AG; polypropylene, PP, (PPN) provided by Höchst AG and polybutene-1, PB-1, Vestolen BT from Chemische Werke Hüls. Thin oriented films were prepared according to the method of Petermann and Gohil, by winding up two different polymer films from two separately heated glass-plates simultaneously with the help of a motor driven cylinder. One double layer was used for TEM investigations, while about 1000 sandwiched layers were taken for mechanical tests.


Author(s):  
Barbara A. Wood

A controversial topic in the study of structure-property relationships of toughened polymer systems is the internal cavitation of toughener particles resulting from damage on impact or tensile deformation.Detailed observations of the influence of morphological characteristics such as particle size distribution on deformation mechanisms such as shear yield and cavitation could provide valuable guidance for selection of processing conditions, but TEM observation of damaged zones presents some experimental difficulties.Previously published TEM images of impact fractured toughened nylon show holes but contrast between matrix and toughener is lacking; other systems investigated have clearly shown cavitated impact modifier particles. In rubber toughened nylon, the physical characteristics of cavitated material differ from undamaged material to the extent that sectioning of heavily damaged regions by cryoultramicrotomy with a diamond knife results in sections of greater than optimum thickness (Figure 1). The detailed morphology is obscured despite selective staining of the rubber phase using the ruthenium trichloride route to ruthenium tetroxide.


1994 ◽  
Vol 72 (01) ◽  
pp. 001-015 ◽  
Author(s):  
Juan J Calvete

SummaryThe glycoprotein (GP) IIb/IIIa, a Ca2+-dependent heterodimer, is the major integrin on the platelet plasma membrane. On resting platelets GPIIb/IIIa is maintained in an inactive conformation and serves as a low affinity adhesion receptor for surface-coated fibrinogen, whereas upon platelet activation signals within the cytoplasma alter the receptor function of GPIIb/IIIa (inside-out signalling), which undergoes a measurable conformational change within its exoplasmic domains, and becomes a competent receptor for soluble fibrinogen and some other RGD sequence-containing plasma adhesive proteins. Upon ligand binding, further structural alterations trigger the association of receptor-occupied GPIIb/IIIa complexes with themselves within the plane of the membrane. The simultaneous binding of dimeric fibrinogen molecules to GPIIb/IIIa clusters on adjacent platelets leads to platelet aggregation, which promotes attachment of fibrinogen-GPIIb/IIIa clusters to the cytoskeleton (outside-in signalling). This, in turn, provides the necessary physical link for clot retraction to occur, and generates a cascade of intracellular biochemical reactions which result in the formation of a multiprotein signalling complex at the cytoplasmic domains of GPIIb/IIIa. Glycoprotein IMIIa, also called αIIbβ3 in the integrin nomenclature, plays thus a primary role in both platelet adhesion and thrombus formation at the site of vascular injury. In addition, the human glycoprotein Ilb/IIIa complex is the most thoroughly studied integrin receptor, its molecular biology and major features of its primary structure having been elucidated mainly during the last six years. Furthermore, localization of functionally relevant monoclonal antibody epitopes, determination of the cross-linking sites of inhibitory peptide ligands, proteolytic dissection of the isolated integrin, and analysis of natural and artificial GPIIb/IIIa mutants have recently provided a wealth of information regarding structure-function relationships of human GPIIb/IIIa. The aim of this review is to summarize these many structural and functional data in the perspective of an emerging model. Although most of the interpretations based on structural elements of this initial biochemical model require independent confirmation, they may help us to understand the structure-function relationship of this major platelet receptor, and of other members of the integrin superfamily, as well as to perform further investigations in order to test current hypotheses.


2020 ◽  
Author(s):  
Alex Stafford ◽  
Dowon Ahn ◽  
Emily Raulerson ◽  
Kun-You Chung ◽  
Kaihong Sun ◽  
...  

Driving rapid polymerizations with visible to near-infrared (NIR) light will enable nascent technologies in the emerging fields of bio- and composite-printing. However, current photopolymerization strategies are limited by long reaction times, high light intensities, and/or large catalyst loadings. Improving efficiency remains elusive without a comprehensive, mechanistic evaluation of photocatalysis to better understand how composition relates to polymerization metrics. With this objective in mind, a series of methine- and aza-bridged boron dipyrromethene (BODIPY) derivatives were synthesized and systematically characterized to elucidate key structure-property relationships that facilitate efficient photopolymerization driven by visible to NIR light. For both BODIPY scaffolds, halogenation was shown as a general method to increase polymerization rate, quantitatively characterized using a custom real-time infrared spectroscopy setup. Furthermore, a combination of steady-state emission quenching experiments, electronic structure calculations, and ultrafast transient absorption revealed that efficient intersystem crossing to the lowest excited triplet state upon halogenation was a key mechanistic step to achieving rapid photopolymerization reactions. Unprecedented polymerization rates were achieved with extremely low light intensities (< 1 mW/cm<sup>2</sup>) and catalyst loadings (< 50 μM), exemplified by reaction completion within 60 seconds of irradiation using green, red, and NIR light-emitting diodes.


2019 ◽  
Vol 18 (13) ◽  
pp. 1796-1814 ◽  
Author(s):  
Sk. Abdul Amin ◽  
Nilanjan Adhikari ◽  
Tarun Jha ◽  
Shovanlal Gayen

Camptothecin (CPT), obtained from Camptotheca acuminata (Nyssaceae), is a quinoline type of alkaloid. Apart from various traditional uses, it is mainly used as a potential cytotoxic agent acting against a variety of cancer cell lines. Though searches have been continued for last six decades, still it is a demanding task to design potent and cytotoxic CPTs. Different CPT analogs are synthesized to enhance the cytotoxic potential as well as to increase the pharmacokinetic properties of these analogs. Some of these analogs were proven to be clinically effective in different cancer cell lines. In this article, different CPT analogs have been highlighted extensively to get a detail insight about the structure-property relationships as well as different quantitative structure-activity relationships (QSARs) modeling of these analogs are also discussed. This study may be beneficial for designing newer CPT analogs in future.


1990 ◽  
Vol 21 (6) ◽  
pp. 1527-1540 ◽  
Author(s):  
D. V. Edmonds ◽  
R. C. Cochrane

Prospects ◽  
2021 ◽  
Author(s):  
Suzanne Lischer ◽  
Netkey Safi ◽  
Cheryl Dickson

AbstractThe disruption caused by Covid-19 in the educational sector may last longer than originally predicted. To better understand the current situation, this article analyses the mental health status of university students during the pandemic and investigates the learning conditions needed to support students. The sample included 557 undergraduate students who took part in an online survey. Overall, the students reported coping well during lockdown but indicated that lecturers were challenged by distance teaching, which created some stress for the students.


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