Silk-inspired polymers and proteins

The biocompatibility and biodegradability of natural silk fibres and the benign conditions under which they (with impressive mechanical properties) are produced represent a biomimetic ideal. This ideal has inspired people in both academia and industry to prepare silk-mimetic polymers and proteins by chemical and/or biotechnological means. in the present paper, we aim to give an overview of the design principles of such silk-inspired polymers/proteins, their processing into various materials morphologies, their mechanical and biological properties, and, finally, their technical and biomedical applications.

Eri silk fibre attributes and sliver preparation

Eri silk produced by Philosamia cynthia ricini silkworm is a fibre not well-known to the silk industry, in spite of the fact that Eri silk is finer, softer, and has better mechanical and thermal properties than most animal fibres. Eri silk has a high commercial potential, as the host plants of Eri silk worms are widespread in diverse geographical locations, and the worms also have a higher degree of disease resistance than most other silk worms. Mills are often not aware of the properties of Eri for designing appropriate end products. Thus, Eri silk yarn is traditionally produced by hand spinning, and Eri silk usually ends up as material for handwoven shawls. The potential for bulk fibre processing and the development of soft luxurious novel Eri silk products is yet to be discovered. To better understand the material and its processing behaviour, Eri silk was characterised and cocoons were processed into tops through degumming, opening, and cutting filaments into different lengths, followed by a worsted spun silk processing route. Fibre properties such as fineness, crimp, strength and length at different processing stages up to combed tops were measured. The results indicate that staple Eri silk can be processed via the worsted topmaking route, using a cut length of 200 mm or 150 mm for filament sheets prepared from degummed cocoons.

Lessons from silkworm cocoons for future protective materials design

 Evolved over millions of years’ natural selection, very thin and lightweight wild silkworm cocoons can protect silkworms from environmental hazards and physical attacks from predators while supporting their metabolic activity. The knowledge of structure-property-function relationship of multi-layered composite silk cocoon shells gives insight into the design of next-generation protection materials. The mechanical and thermal insulation properties of both domestic (Bombyx mori, or B. moriand Samia. cynthia, or S. cynthia) and wild (Antheraea pernyi and Antheraea mylitta, or A. pernyi and A. mylitta) silkworm cocoons were investigated. The research findings are of relevance to the bio-inspired design of new protective materials and structures.
The 180 degree peel tests and needle penetration tests were used for examining the peel resistance and needle penetration resistance of both domestic and wild silkworm cocoon walls. The temperatures inside and outside of the whole silkworm cocoons under warm, cold and windy conditions were monitored for investigating the cocoon’s thermal insulation function. Computational fluid dynamics (CFD) models were created to simulate the heat transfer through the A. pernyi cocoon wall.
The wild cocoons experienced much higher peeling peak loads than the domestic cocoon. This transfers to a maximum work-of-fracture (WOF) of about 1000 J/m2 from the A. pernyi outer layer, which was 10 times of the B. mori cocoon. The A. pernyi wild cocoon exhibited a maximum penetration force (11 N) that is 70 % higher than a woven aramid fabric. Silk sericin is shown to play a critical role in providing needle penetration resistance of the non-woven composite cocoon structure by restricting the relative motion of fibres, which prevents the sharp tip of the needle from pushing aside fibres and penetrating between them. The wild A. pernyi cocoon exhibits superior thermal buffer over the domestic B. mori cocoon. The unique structure of the A. pernyi cocoon wall with mineral crystals deposited on the cocoon outer surface, can prohibit most of the air from flowing inside of the cocoon structure, which shows strong wind resistance under windy conditions.

DNA polymerase alpha-primase complex from the silk glands of the non-mulberry silkworm Philosamia ricini.

The DNA content in the silk glands of the non-mulberry silkworm Philosamia ricini increases continuously during the fourth and fifth instars of larval development indicating high levels of DNA replication in this terminally differentiated tissue. Concomitantly, the DNA polymerase alpha activity also increases in the middle and the posterior silk glands during development, reaching maximal levels in the middle of the fifth larval instar. A comparable level of DNA polymerase delta/epsilon was also observed in this highly replicative tissue. The DNA polymerase alpha-primase complex from the silk glands of P. ricini has been purified to homogeneity by conventional column chromatography as well as by immunoaffinity techniques. The molecular mass of the native enzyme is 560 kDa and the enzyme comprises six non-identical subunits. The identity of the enzyme as DNA polymerase alpha has been established by its sensitivity to inhibitors such as aphidicolin, N-ethylmaleimide, butylphenyl-dGTP, butylanilino-dATP and antibodies to polymerase alpha. The enzyme possesses primase activity capable of initiating DNA synthesis on single-stranded DNA templates. The tight association of polymerase and primase activities at a constant ratio of 6:1 is observed through all the purification steps. The 180 kDa subunit harbours the polymerase activity, while the primase activity is associated with the 45 kDa subunit.

The Cynthia Woods incident: When the rescuer becomes the rescuee

Survival at sea for Steven Conway and five Texas A&M University at Galveston students after the sinking of the sailboat Cynthia Woods.

Liver-directed lentiviral gene therapy in a dog model of hemophilia B

We investigated the efficacy of liver-directed gene therapy using lentiviral vectors in a large animal model of hemophilia B and evaluated the risk of insertional mutagenesis in tumor-prone mouse models. We showed that gene therapy using lentiviral vectors targeting the expression of a canine factor IX transgene in hepatocytes was well tolerated and provided a stable long-term production of coagulation factor IX in dogs with hemophilia B. By exploiting three different mouse models designed to amplify the consequences of insertional mutagenesis, we showed that no genotoxicity was detected with these lentiviral vectors. Our findings suggest that lentiviral vectors may be an attractive candidate for gene therapy targeted to the liver and may be potentially useful for the treatment of hemophilia.

Cynthia Kim fonds, 2012-2015

Cynthia Kim was diagnosed with Asperger’s syndrome when she was 42 years old. She has contributed articles to Autism Parenting magazine, Thinking Person’s Guide to Autism, and Autism West Midlands’ magazine. She has also written two books on autism, I Think I Might Be Autistic: A Guide to Autism Spectrum Disorder Diagnosis and Self-Discovery for Adults, and Nerdy, Shy, and Socially Inappropriate: A User Guide to an Asperger Life.

Risking the ire of investors in pursuit of long-term value: an interview with Cynthia Carroll, the CEO of Anglo American plc

Purpose – The purpose of this paper is to demonstrate how key strategic decisions are made in practice at successful FTSE 100 companies. Design/methodology/approach – The paper is based on a semi-structured interview with Ms Cynthia Carroll, Chief Executive of Anglo American plc. Findings – The interview outlines a number of important factors on: the evolution of strategy within Anglo American, strategy execution, leadership at board and executive levels, and capturing synergies within the company. Originality/value – The paper bridges the gap between theory and practice. It provides a practical view and demonstrates how corporate leaders think about key strategic issues

Interview with Cynthia Venables

In her July 3, 2013 interview with Martha Manning, Cynthia Burris Venables shares her experiences at Winthrop from 1985-1989, as well as her career teaching English. Discussed is Venables coursework as an English major and the rigor of her studies. Additionally, Venables talks about Latin and Biology courses and who her favorite professors were. Venables details what it is like teaching in the 21st Century, her opinions on technology and teaching, and her accomplishments as an educator. This interview was conducted for inclusion into the Louise Pettus Archives and Special Collections Oral History Program.