1,721,789 research outputs found
Oral History Interview, Govindjee (2103)
No full textIn his interview with Joy Block on October 15, 2016, Dr. Govindjee, former Professor Emeritus of Biochemistry, Biophysics and Plant Biology at the University of Illinois at Urbana-Champaign, talks about growing up in India and his family there. To learn more about this oral history, download & review the index first (or transcript if available). It will help determine which audio file(s) to download & listen to.In his interview with Joy Block on October 15, 2016, Dr. Govindjee, former Professor Emeritus of Biochemistry, Biophysics and Plant Biology at the University of Illinois at Urbana-Champaign, talks about growing up in India and his family there. He also discusses his memories of the Indian independence movement and his experience moving to the United States. This interview was conducted for Joy Block’s South Asian Oral Histories project and is housed in the Oral History Collection at the UW-Madison Archives
Defining the Urban Edge - A Guide to its Implementation for Sustainable Development
No full textAs relics of the legacy of apartheid, the boundaries of cities have expanded exponentially. The notion of the urban edge has therefore been introduced as a planning tool to prevent further sprawl and has become an integral part of spatial planning. Court judgments provide guidelines for the interpretation of the notion, but they do not give direction regarding how it should be implemented.
Various factors, both planning and environmental, impact on the success or failure of the implementation of the urban edge. It is also a Spatial Planning and Land Use Management Act 16 of 2013 (SPLUMA) requirement that the drafting of the Spatial Development Framework (SDF) (which may incorporate an urban edge) must consider environmental management instruments.
The demarcation and periodic review of an urban edge is an important and complex exercise. The writer submits that an acceptable definition of it is necessary to help resolve the difficulties involved in this process. Section 24 of the Constitution (which is indicative of a compact and sustainable urban environment) requires consideration, as do the interdependence of urban and rural areas. Having a uniform definition of the urban edge would be useful as a guideline to municipalities when demarcating and managing it.
As the urban edge may be depicted in a municipal SDF in terms of SPLUMA, and as it is a planning tool, it is recommended that the definition be established by and included in SPLUMA. The definition proposed below incorporates various elements found in existing definitions
Honoring two stalwarts of photosynthesis research: Eva-Mari Aro and Govindjee
No full textOn behalf of the entire photosynthesis community, it is an honor, for us, to write about two very eminent scientists who were recently recognised with a Lifetime Achievement Award from the International Society of Photosynthesis Research (ISPR) on August 5, 2022; this prestigious Award was given during the closing ceremony of the 18th International Congress on Photosynthesis Research in Dunedin, New Zealand. The awardees were: Professor Eva-Mari Aro (Finland) and Professor Emeritus Govindjee Govindjee (USA). One of the authors, Anjana Jajoo, is especially delighted to be a part of this tribute to professors Aro and Govindjee as she was lucky enough to have worked with both of them
My contact and cooperation with Govindjee over the last five decades: Chlorophyll fluorescence and Rebeiz Foundation
No full textGovindjee and Hartmut Lichtenthaler have a very similar curriculum vitae. Both chose photosynthesis as research field and actively applied chlorophyll fluorescence. Their research was overlapping and complementary. On the occasion of Govindjee\u27s 88th anniversary in 2020, Hartmut Lichtenthaler gives a short retrospective on interactions and joint activities with Govindjee over the past five decades
Photosyntesis: development, carbon metabolism, and plant productivity. Jilid I/ Govindjee
No full textIs bicarbonate in Photosystem II the equivalent of the glutamate ligand to the iron atom in bacterial reaction centers?
No full textPhotosystem II of oxygen-evolving organisms exhibits a bicarbonate-reversible formate effect on electron transfer between the primary and secondary acceptor quinones, QA and QB. This effect is absent in the otherwise similar electron acceptor complex of purple bacteria, e.g. Rhodobacter sphaeroides. This distinction has led to the suggestion that the iron atom of the acceptor quinone complex in PS II might lack the fifth and sixth ligands provided in the bacterial reaction center (RC) by a glutamate residue at position 234 of the M-subunit in Rb. sphaeroides,RCs (M232 in Rps. viridis). By site-directed mutagenesis we have altered GluM234 in RCs from Rb. sphaeroides, replacing it with valine, glutamine and glycine to form mutants M234EV, M234EQ and M234EG, respectively. These mutants grew competently under phototrophic conditions and were tested for the formate-bicarbonate effect. In chromatophores there were no detectable differences between wild type (Wt) and mutant M234EV with respect to cytochrome b-561 reduction following a flash, and no effect of bicarbonate depletion (by incubation with formate). In isolated RCs, several electron transfer activities were essentially unchanged in Wt and M234EV, M234EQ and M234EG mutants, and no formate-bicarbonate effect was observed on: (a) the fast or slow phases of recovery of the oxidized primary donor (P+) in the absence of exogenous donor, i.e., the recombination of P+QA− or P+QB−, respectively; (b) the kinetics of electron transfer from QA− to QB; or (c) the flash dependent oscillations of semiquinone formation in the presence of donor to P+ (QB turnover). The absence of a formate-bicarbonate effect in these mutants suggests that GluM234 is not responsible for the absence of the formate-bicarbonate effect in Wt bacterial RCs, or at least that other factors must be taken into account. The mutant RCs were also examined for the fast primary electron transfer along the active (A-)branch of the pigment chain, leading to reduction of QA. The kinetics were resolved to reveal the reduction of the monomer bacteriochlorophyll (τ = 3.5 ps), followed by reduction of the bacteriopheophytin (τ = 0.9 ps). Both steps were essentially unaltered from the wild type. However, the rate of reduction of QA was slowed by a factor of 2 (τ = 410 ± 30 and 47 ± 30 ps for M234EQ and M234EV, respectively, compared to 220 ps in the wild type). EPR studies of the isolated RCs showed a characteristic g = 1.82 signal for the QA semiquinone coupled to the iron atom, which was indistinguishable from the wild type. It is concluded that GluM234 is not essential to the normal functioning of the acceptor quinone complex in bacterial RCs and that the role of bicarbonate in PS II is distinct from the role of this residue in bacterial RCs
Photosyntesis: development, carbon metabolism, and plant productivity. JiIlid II./ Govindjee
No full textxxv, 580 ha.: bibl.; ill.; ind.; 21 cm
An Evaluation of Strain Amplification Concepts via Monte Carlo Simulations of an Ideal Composite
No full textAbstract
In the modeling of carbon-black filled elastomers it is important to have a good estimate of the state of the elastomer itself, since many nonlinear effects originate in the matrix material. A common notion in such estimates is the idea of a “strain amplification” factor that relates a macroscopically imposed strain state to the average strain state in the elastomer matrix material. In this paper Mullins and Tobin's interpretation of the Guth—Gold and Smallwood's amplification factor, and a more recent proposal by Govindjee and Simo will be examined. All three theories are compared to the results of a series of Monte Carlo simulations on an ideal composite with a Neo-Hookean matrix and semi-rigid inclusions. It is shown that for the idealized material, one can not interpret the Guth—Gold and Smallwood amplification factors as an estimate of the strain state of the matrix material. The theory of Govindjee and Simo, on the other hand, is shown to accurately predict the strain state of the matrix.</jats:p
Gordon research conference on photosynthesis : from evolution of fundamental mechanisms to radical re-engineering
No full textWe provide here a News Report on the 2014 Gordon Research Conference on Photosynthesis, with the subtitle "From Evolution of Fundamental Mechanisms to Radical Re-Engineering." It was held at Mount Snow Resort, West Dover, Vermont, during August 10-15, 2014. After the formal sessions ended, four young scientists (Ute Ambruster of USA; Han Bao of USA; Nicoletta Liguori of the Netherlands; and Anat Shperberg-Avni of Israel) were recognized for their research; they each received a book from one of us (G) in memory of Colin A. Wraight (1945-2014), a brilliant and admired scientist who had been very active in the bioenergetics field in general and in past Gordon Conferences in particular, having chaired the 1988 Gordon Conference on Photosynthesis. (See an article on Wraight by one of us (Govindjee) at http://www.life.illinois.edu/plantbio/Features/ColinWraight/ColinWraight.html .).</p
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