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9. Machian strings as an alternative to dark energy

Author

Essex, David W.

Subjects
Physics - General Physics
Abstract

The expansion history of the Universe is calculated using a simple model in which the entire rest mass energy of a massive particle is distributed throughout the set of Machian strings connecting it to all the other particles in the observable Universe. With the assumption that the energy in a Machian string has the form of positive Newtonian potential energy, the deceleration rates in the radiation and matter eras are exactly the same as in the conventional $\Lambda$CDM model. The transition from deceleration to acceleration at the present time is obtained by making the simplest possible modification of the Newtonian potential energy to represent the effect of the cosmological expansion. The effective dark matter and dark energy densities are calculated in terms of the speed of the Hubble flow at the radius of the observable Universe., Comment: 4 pages, 5 figures, reference added

Published
2016

10. Machian strings as an alternative to dark matter

Author

Essex, David W.

Subjects
Physics - General Physics
Abstract

Dark matter effects may be attributed to interactions between the Machian strings connecting every pair of elementary particles in the observable Universe. A simple model for the interaction between Machian strings is proposed. In the early Universe, the Machian strings of a density perturbation had a spherically symmetric distribution and the interaction with the Machian strings of a test particle is found to give a multiple of the Newtonian gravitational acceleration. In a strong gravitational field, the interaction between Machian strings tends to a constant limit in order to ensure the absence of dark matter effects in the Solar System. Dark matter effects on a galactic scale may be attributed to a change in the distribution of the Machian strings around a galaxy during the process of galaxy formation. The interaction between the Machian strings of a test mass and the Machian strings of a galaxy is considered in detail and the MOND phenomenology for galaxy rotation curves is obtained., Comment: 12 pages, 8 figures, reference added

Published
2016

12. Galaxy clusters and the nature of Machian strings

Author

Essex, David W.

Subjects
Physics - General Physics
Abstract

The model of Machian space quanta is applied to the dark matter problem in galaxy clusters. Machian space quanta are able to solve the missing mass problem if all the mass of a space quantum is assumed to be in the Machian strings., Comment: 8 pages, 9 figures

Published
2015

13. Machian space quanta

Author

Essex, David W.

Subjects
Physics - General Physics
Abstract

A new model for space and matter is obtained by joining every pair of point charges in the observable universe by an ethereal string. Positive gravitational potential energy in each string gives an attractive gravitational force due to the action of an energy conservation constraint. Newton's laws of motion are derived and inertia is explained in accordance with Mach's principle. The Machian string model gives a surprisingly simple way to understand the expansion history of the Universe. The decelerating expansion in the radiation era and the matter era is explained without using General Relativity and the transition from deceleration to acceleration is explained without the need to introduce a separate 'dark energy' component. The interaction between Machian strings gives a physical model for modified Newtonian dynamics (MOND) and is therefore an alternative to 'dark matter'., Comment: 24 pages, 12 figures

Published
2015

18. Protein disulfide isomerase A1 as a novel redox sensor in VEGFR2 signaling and angiogenesis

Author

Nagarkoti, Sheela, primary, Kim, Young-Mee, additional, Ash, Dipankar, additional, Das, Archita, additional, Vitriol, Eric, additional, Read, Tracy-Ann, additional, Youn, Seock-Won, additional, Sudhahar, Varadarajan, additional, McMenamin, Malgorzata, additional, Hou, Yali, additional, Boatwright, Harriet, additional, Caldwell, Ruth, additional, Essex, David W., additional, Cho, Jaehyung, additional, Fukai, Tohru, additional, and Ushio-Fukai, Masuko, additional

Published
2022
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21. The C-terminal CGHC motif of protein disulfide isomerase supports thrombosis

Author

Zhou, Junsong, Wu, Yi, Wang, Lu, Rauova, Lubica, Hayes, Vincent M., Poncz, Mortimer, and Essex, David W.

Subjects
Blood clot -- Research -- Genetic aspects -- Development and progression -- Care and treatment -- Patient outcomes, Thrombosis -- Research -- Genetic aspects -- Development and progression -- Care and treatment -- Patient outcomes, Genetic engineering -- Research, Health care industry
Abstract

Protein disulfide isomerase (PDI) has two distinct CGHC redox-active sites; however, the contribution of these sites during different physiologic reactions, including thrombosis, is unknown. Here, we evaluated the role of PDI and redox-active sites of PDI in thrombosis by generating mice with blood cells and vessel wall cells lacking PDI (Mx1-Cre [Pdi.sup.fl/fl] mice) and transgenic mice harboring PDI that lacks a functional C-terminal CGHC motif [PDI(ss-oo) mice]. Both mouse models showed decreased fibrin deposition and platelet accumulation in laser-induced cremaster arteriole injury, and PDI(ss-oo) mice had attenuated platelet accumulation in Fe[Cl.sub.3]-induced mesenteric arterial injury. These defects were rescued by infusion of recombinant PDI containing only a functional C-terminal CGHC motif [PDI(oo-ss)]. PDI infusion restored fibrin formation, but not platelet accumulation, in eptifibatide-treated wild-type mice, suggesting a direct role of PDI in coagulation. In vitro aggregation of platelets from PDI(ss-oo) mice and PDI-null platelets was reduced; however, this defect was rescued by recombinant PDI(oo-ss). In human platelets, recombinant PDI(ss-oo) inhibited aggregation, while recombinant PDI(oo-ss) potentiated aggregation. Platelet secretion assays demonstrated that the C-terminal CGHC motif of PDI is important for P-selectin expression and ATP secretion through a non-αTIβ53 substrate. In summary, our results indicate that the C-terminal CGHC motif of PDI is important for platelet function and coagulation., Introduction Protein disulfide isomerase (PDI) is the prototypic member of the PDI family of enzymes that catalyze the reversible formation and isomerization of disulfide bonds (1). Platelet PDI mediates platelet [...]

Published
2015
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23. Protein Disulfide Isomerase A1 functions as a Novel Redox Sensor in VEGFR2 Signaling and Angiogenesis

Author

Nagarkoti, Sheela, primary, Kim, Young-Mee, additional, Ash, Dipankar, additional, Seock -Wonoun, Y., additional, Hou, Yali, additional, Boatwright, Harriet, additional, McMenamin, Maggie, additional, Caldwell, Ruth, additional, Essex, David W., additional, Cho, Jaehyung, additional, Fukai, Tohru, additional, and Ushio-Fukai, Masuko, additional

Published
2022
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27. Redox control of platelet aggregation

Author

Essex, David W. and Li, Mengru

Subjects
Oxidation-reduction reaction -- Analysis, Sulfides -- Physiological aspects, Metabolism -- Physiological aspects, Blood platelets -- Physiological aspects, Glutathione -- Physiological aspects, Fibrinogen -- Physiological aspects, Biological sciences, Chemistry
Abstract

Research has been conducted on platelet aggregation. The role of redox buffer in platelet aggregation and the effect of the reduced gluthione and platelet activation on sulfhydryl exposure in platelet fibrinogen receptor have been investigated and discussed.

Published
2003

28. Protein disulfide isomerase and sulfhydryl-dependent pathways in platelet activation

Author

Essex, David W., Li, Mengru, Miller, Anna, and Feinman, Richard D.

Subjects
Blood platelets -- Activation, Platelet activating factor -- Analysis, Enzyme activation -- Physiological aspects, Biological sciences, Chemistry
Abstract

Results show that platelet activation and secretion involve protein disulfide isomerase as well as sulfhydryl-dependent molecules. Data indicate that about nine surface proteins including the fibrinogen receptor protein of the platelet react with thiol-specific reagents during the activation process.

Published
2001

30. Protein disulfide isomerase catalyzes the formation of disulfide-linked complexes of vitronectin with thrombin-antithrombin

Author

Essex, David W., Miller, Anna, Swiatkowska, Maria, and Feinman, Richard D.

Subjects
Isomerases -- Research, Thrombin -- Research, Blood platelets -- Research, Biological sciences, Chemistry
Abstract

Purified preparations of platelet protein disulfide isomerase (PDI), vitronectin, alpha-thrombin and antithrombin (AT) were employed to show that PDI catalyzes the formation of vitronectin-thrombin-AT complexes. Findings may also elucidate on previous research indicating that vitronectin-thrombin-AT complexes form better in plasma than with purified proteins. A PDI was purified from plasma that was immunologically similar to the platelet enzyme.

Published
1999

39. Bringing it all together: SOA design plays a key role in paring down secret data-sharing links

Author

Essex, David

Subjects
Market trend/market analysis, Technology application, United States. Department of Defense -- Technology application, Data communications -- Forecasts and trends -- Usage -- Technology application, Service oriented architecture (Software design) -- Usage -- Technology application -- Forecasts and trends, Intelligence service -- Technology application -- Forecasts and trends -- Usage
Abstract

For decades, the Defense Department and intelligence agencies cultivated a garden of specialized technologies that shifted classified data--typically files, text chat and e-mail--across security classifications and network domains. As a […]

Published
2007

40. Cities make financial sense of WiFi projects: municipalities try to build their business plans around wireless access

Author

Essex, David

Subjects
Technology application, Government communications regulation, Municipal services -- Services -- Technology application -- Social aspects -- Usage -- Economic aspects, Wi-Fi -- Usage -- Standards -- Social aspects -- Economic aspects -- Technology application, United States -- Telecommunications policy
Abstract

THERE WAS SOMETHING so darned utopian about the whole idea: Bypass the powerful telco companies, string up some IEEE 802.11 wireless access points and give citizens free or substantially subsidized […]

Published
2006

41. RFID Technologies duke it out: UHF has a greater reach, but HF has better defense. So, which one do you put your money on?

Author

Essex, David

Subjects
Data security issue, Technology application, Radio frequency identification, Smart card, United States. Department of State -- Technology application -- Standards, United States. Department of Homeland Security -- Technology application -- Standards, Data security -- Standards -- Usage -- Technology application, Radio frequency identification (RFID) -- Usage -- Standards, Integrated circuit cards -- Usage -- Standards, Smart cards -- Usage -- Standards
Abstract

And you thought the fight over radio frequency identification technology was all about whether Big Brother would be able to track unsuspecting individuals as they go about their daily lives. […]

Published
2006

42. In the know: in post-9/11 era, knowledge management tools let agencies cross organizational lines and measure performance

Author

Essex, David

Subjects
Company systems management, Market trend/market analysis, Technology application, Knowledge management, Federal government -- Information services, Knowledge management -- Forecasts and trends -- Technology application -- Political aspects
Abstract

IF THERE HAS EVER BEEN a term of art in IT, it is knowledge management. More a buzzword than a real category, it usually adorns software whose primary purpose is […]

Published
2006

43. Cart blanche: NIH's ECS III gives agencies lots of latitude in making hardware buys

Author

Essex, David

Subjects
Clinger-Cohen Act of 1996, Company systems management, United States. General Services Administration -- Services -- Information management, Federal government -- Information services
Abstract

FOR DECADES, the federal government has sought to economize on the billions of dollars it spends on goods, services and property. It is the main reason the General Services Administration […]

Published
2006

46. Keep your eye on IP telephony: UC systems, which already come with built-in IP integration, are gradually taking on the characteristics of a more distributed, embedded architecture that fits nicely wihin the peer-to-peer, software-driven, Web-enabled networking that IP allows. (Enterprise Messaging)

Author

Essex, David

Abstract

The parallel but closely related IP telephony trend is having a major impact on the Unified Communications (UC) market. So-called IP 'soft phones,' for example, can reside nearly anywhere, be […]

Published
2002

47. Managing know-how: pair an industrial-strength search engine with a portal and you get a virtual data repository of corporate knowledge ... if the integrations don't get you first. (Datamining)(Cover Story)

Author

Essex, David

Subjects
MIS, Company business management, Information technology, Information systems, Information technology -- Management, Management information systems
Abstract

There's a goldmine of underused information resources in most organizations. Buzzword after buzzword has promised to help exploit it ... and largely failed. Document management gave way to groupware and […]

Published
2002

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