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1990

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Articles 1 - 30 of 52

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan Dec 1990

A Temperature-Sensitive Mutant Of Escherichia Coli Affected In The Alpha Subunit Of Rna Polymerase, Majid Mehrpouyan

Electronic Theses and Dissertations

A temperature-sensitive mutant of Escherichia coli affected in the alpha subunit of RNA polymerase has been investigated. Gene mapping and complementation experiments placed the mutation to temperature-sensitivity within the alpha operon at 72 min on the bacterial chromosome. The rate of RNA synthesis in vivo and the accumulation of ribosomal RNA were significantly reduced in the mutant at 44$\sp\circ$C. The thermostability at 44$\sp\circ$C of the purified holoenzyme from mutant cells was about 20% of that of the normal enzyme. Assays with T7 DNA as a template showed that the fraction of active enzyme competent ...


Adsorption To Dipalmitoylphosphatidylcholine Membranes In Gel And Fluid State: Pentachlorophenolate, Dipicrylamine, And Tetraphenylborate, Pavel Smejtek, S. R. Wang Nov 1990

Adsorption To Dipalmitoylphosphatidylcholine Membranes In Gel And Fluid State: Pentachlorophenolate, Dipicrylamine, And Tetraphenylborate, Pavel Smejtek, S. R. Wang

Physics Faculty Publications and Presentations

We measured the dependence of electrophoretic mobility of dipalmitoylphosphatidylcholine (DPPC) vesicles on the aqueous concentration of negatively charged ions of pentachlorophenol (PCP), dipicrylamine (DPA), and tetraphenylborate (TPhB). The objective was to determine how the physical state of hydrocarbon chains of lipids affects adsorption of lipophilic ions. The studies were done at 25 and 42 degrees C to determine adsorption properties of DPPC membrane in the gel and fluid state, respectively. From the analysis of zeta-potential isotherms in terms of Langmuir-Stern-Grahame model we obtained the association constant, K, the area of the adsorption site, Ps, and the linear partition coefficient, beta ...


Functional And Structural Characterization Of A Human H4 Histone Gene Promoter: A Thesis, Kenneth Lynn Wright Nov 1990

Functional And Structural Characterization Of A Human H4 Histone Gene Promoter: A Thesis, Kenneth Lynn Wright

GSBS Dissertations and Theses

Expression of the cell cycle dependent FO10S human H4 histone gene is regulated at both the transcriptional and post-transcriptional levels. We have investigated the 5' promoter elements mediating the transcriptional aspects of its regulation. A detailed in vivo and in vitro transcriptional analysis of promoter deletion mutants from this gene has identified three positive regulatory elements and two potentially negative regulatory elements within the first 1000 base pairs upstream of the transcription initiation site. In addition, the minimal promoter located within the first 70 base pairs is required for accurate transcription initiation and contains one of two in vivo identified ...


Interaction Between The Component Enzymes Of The Glycine Decarboxylase Multienzyme Complex, David J. Oliver, Michel Neuburger, Jacques Bourguignon, Roland Douce Oct 1990

Interaction Between The Component Enzymes Of The Glycine Decarboxylase Multienzyme Complex, David J. Oliver, Michel Neuburger, Jacques Bourguignon, Roland Douce

David J. Oliver

The glycine decarboxylase multienzyme complex comprises about one-third of the soluble protein of the matrix of pea (Pisum sativum) leaf mitochondria where it exists at a concentration of approximately 130 milligrams protein/milliliter. Under these conditions the complex is stable with an approximate subunit ratio of 2 P-protein dimers:27 H-protein monomers:9 T-protein monomers:1 L-protein dimer. When the complex is diluted it tends to dissociate into its component enzymes. This prevents the purification of the intact complex by gel filtration or ultracentrifugation. In the dissociated state the H-protein acts as a mobile cosubstrate that commutes between the other ...


Mega Doses Of Methotrexate In The Treatment Of Osteosarcoma, M P. Iqbal, I A. Malik Oct 1990

Mega Doses Of Methotrexate In The Treatment Of Osteosarcoma, M P. Iqbal, I A. Malik

Department of Biological & Biomedical Sciences

Abstract is not provided by the author/publisher


Novel Noninvasive In Situ Probe Of Protein Structure And Dynamics, M. Negrerie, S. M. Bellefeuille, Steven A. Whitham, Jacob W. Petrich, R. W. Thornburg Sep 1990

Novel Noninvasive In Situ Probe Of Protein Structure And Dynamics, M. Negrerie, S. M. Bellefeuille, Steven A. Whitham, Jacob W. Petrich, R. W. Thornburg

Chemistry Publications

7-Amtryptophan is an ideal noninvasive in situ probe of protein structure and dynamics and provides an alternative to the use of ,tryptophan. 7-Azatryptophan affords a single-exponential fluorescence decay in aqueous solution, unlike tryptophan. Its absorption and fluorescence spectra are distinguishable from those of tryptophan. Its fluorescence spectrum and lifetime are sensitive to the environment. It can be used in peptide synthesis, and it can be incorporated into bacterial protein. These facts render 7-azatryptophan a unique probe that has the potential for widespread use.


Laminin Potentiates Differentiation Of Pcc4uva Embryonal Carcinoma Into Neurons, T. M. Sweeney, Roy C. Ogle, C. D. Little Sep 1990

Laminin Potentiates Differentiation Of Pcc4uva Embryonal Carcinoma Into Neurons, T. M. Sweeney, Roy C. Ogle, C. D. Little

Medical Diagnostics & Translational Sciences Faculty Publications

The embryonal carcinoma PCC4uva differentiates into neurons in response to treatment with retinoic acid and dbcAMP. We used this in vitro model system to study the effects of laminin on early neural differentiation. Laminin substrata markedly potentiate neural differentiation of retinoic acid and dbcAMP-treated cultures. Only laminin induced more rapid neural cell body clustering, neurite growth and neurite fasciculation as compared to type IV collagen, type I collagen, and fibronectin substrata. Exogenous laminin substrata promoted greater cell attachment, cellular spreading and growth to confluence than type IV collagen, type I collagen, fibronectin and glass substrata. Laminin-induced effects were inhibited by ...


Kinematic Considerations Of Elite Alpine Slalom Ski Racers, David Andrew Goodwin Aug 1990

Kinematic Considerations Of Elite Alpine Slalom Ski Racers, David Andrew Goodwin

Master's Theses

This study described specific kinematic parameters associated with success on the international level in alpine slalom ski racing. Sixteen male athletes representing twelve countries comprised the subject pool. Subject selection was based on finish position in the men's special slalom at the 1989 World Alpine Ski Championships in Vail, Colorado. Cinematographical records were analyzed by a method known as direct linear transformation.

The findings of the study indicated that: (a) hip and knee joint angles of the turning leg must approximate 1.80 to 1.83 radians and 1.82 to 2.21 radians, respectively, for efficiency in this ...


Highway Deicing Salts And The Mobilization Of Selected Heavy Metals From Stream Sediments, Harlie David Cole Aug 1990

Highway Deicing Salts And The Mobilization Of Selected Heavy Metals From Stream Sediments, Harlie David Cole

Dissertations

This study was undertaken to: (a) determine the effect of sodium chloride concentration on mobilizing cadmium, copper, lead, nickel, and zinc from stream sediments; (b) determine if chloro-metal complexes may play a role in any such mobilization; and (c) determine the correlations between chloride ion and each of these metals in an urban stream during winter road-salting periods.

The drainage basin of the Red Run, an urban stream draining all or parts of several cities north of Detroit, Michigan, was chosen as a study site. Stream sediments containing the five heavy metals were stirred with sodium chloride or sodium nitrate ...


Trace Element Studies On Karachi Populations Part V: Blood Lead Levels In Normal Healthy Adults And Grammar School Children, W W. Manser, R Lalani, S Haider, M A. Khan Jul 1990

Trace Element Studies On Karachi Populations Part V: Blood Lead Levels In Normal Healthy Adults And Grammar School Children, W W. Manser, R Lalani, S Haider, M A. Khan

Department of Biological & Biomedical Sciences

Blood lead levels of healthy Karachi population were estimated. Mean levels for males, females, soldiers and school children were 34.4, 31.8, 29.9 and 38.2 micrograms/dl respectively. About 93% cases of either sex had elevated lead levels, of whom 30% males and 10% females had levels above the safety limits (40 micrograms/dl). Soldiers living in relatively pollution free area though had levels lower than the rest of the population but 91% had levels over 25 micrograms/dl and only two had acceptable levels. Ninety-two percent children showed levels above 25 micrograms/dl with a large ...


Replication And Amplification Of Defective Interfering Particle Rn As Of Vesicular Stomatitis Virus In Cells Expressing Viral Proteins From Vectors Containing Cloned Cdnas, Asit K. Pattnaik, Gail W. Wertz Jun 1990

Replication And Amplification Of Defective Interfering Particle Rn As Of Vesicular Stomatitis Virus In Cells Expressing Viral Proteins From Vectors Containing Cloned Cdnas, Asit K. Pattnaik, Gail W. Wertz

Papers in Veterinary and Biomedical Science

Replication and amplification of RNA genomes of defective interfering (DI) particles of vesicular stomatitis virus (VSV) depend on the expression of viral proteins and have untD now been attained only in ceUs coinfected with helper VSV. In the work described in this report, we used a recombinant vaccinia virus-T7 RNA polymerase expression system to synthesize individual VSV proteins in cells transfected with plasmid DNAs that contain cDNA copies of the VSV genes downstream of the T7 RNA polymerase promoter. In this way, we were able to examine the ability of VSV proteins, individually and in combination, to support DI particle ...


Purification And Characterization Of Enoyl-Acp Reductase From Euglena Gracilis, Margie M. Tucker May 1990

Purification And Characterization Of Enoyl-Acp Reductase From Euglena Gracilis, Margie M. Tucker

Electronic Theses and Dissertations

Enoyl-(acyl-carrier-protein) reductase was purified from the phytoflagellate Euglena gracilis. Its purification employed DEAE-Sephacel chromatography, Matrex Orange chromatography, and affinity chromatography using acyl carrier protein (ACP) covalently bound to Sepharose as the affinity ligand. Matrex Orange chromatography resolved two different enoyl-ACP reductases having different characteristics. Euglena gracilis appears to resemble higher plants in the possession of two isoforms of this enzyme. Antibodies specific for the cofactor binding site of NADP (H)-requiring dehydrogenases were obtained. They were isolated from a polyclonal population of antibodies directed against yeast glucose-6-phosphate dehydrogenase by affinity chromatography using chicken liver malic enzyme as the affinity ...


Energetic Requirements For Bacterial Protein Export, John Andrew Corbett May 1990

Energetic Requirements For Bacterial Protein Export, John Andrew Corbett

All Graduate Theses and Dissertations

Bacterial protein export involves the translocation of precursor proteins across the inner cytoplasmic membrane. Over 100 proteins are exported from Escherichia coli. This study showed that energy in the form of ATP and membrane gradient energy is essential for the export of leucine specific binding protein and (3-lactamase precursors. Ionophores or combinations of ionophores (SF6847, valinomycin/nigericin and valinomycin/monensin) which dissipate protonmotive force inhibit protein export. Valinomycin alone also inhibits export, but not as well as reagents which dissipate protonmotive force. Nigericin or monensin alone slightly stimulate protein export. These results suggest that the transmembrane electrical potential ( DY) is ...


Deercare: A Deer Population And Hunting Simulation Model, Claude Barnett, David Stewart, Charles Amlaner Apr 1990

Deercare: A Deer Population And Hunting Simulation Model, Claude Barnett, David Stewart, Charles Amlaner

Charles J. Amlaner

No abstract provided.


The Introduction Of Simulation Modeling To Wildlife Management In Arkansas, Charles Amlaner, Claude Barnett, David Stewart Apr 1990

The Introduction Of Simulation Modeling To Wildlife Management In Arkansas, Charles Amlaner, Claude Barnett, David Stewart

Charles J. Amlaner

No abstract provided.


Topoisomerase Ii In The Inactive X Chromosome As Determined By Immunofluorescence, Ronald Lehmann Apr 1990

Topoisomerase Ii In The Inactive X Chromosome As Determined By Immunofluorescence, Ronald Lehmann

Life and Environmental Sciences Undergraduate Theses

Topoisomerases are enzymes that convert DNA from one topological state to another. A particular type of topoisomerase, type II, appears also to be a member of the chromosome scaffold, bound to the base of radial DNA loops. Using immunofluorescence coupled with DNase digestions, we determined an association between the topoisomerase II and the sex chromatin body. Based upon this association, we postulate that topoisomerase II may be involved in the compartmentalization of the sex chromatin body. Since no topoisomerase II has been detected in the G-] phase of the cell cycle, topoisomerase II must act with other, yet to be ...


Bilirubin-Albumin Binding At Varying Conditions Of Hematocrit, Sodium Benzoate Concentration, And Bilirubin/Albumin Molar Ratios, Patrick Ahrens Apr 1990

Bilirubin-Albumin Binding At Varying Conditions Of Hematocrit, Sodium Benzoate Concentration, And Bilirubin/Albumin Molar Ratios, Patrick Ahrens

Life and Environmental Sciences Undergraduate Theses

Hyperbilirubinemia, which causes jaundice, is quite common in newborns. Typically bilirubin is bound to its carrier protein albumin and very little unbound bilirubin is present in the blood. However, in cases of hyperbilirubinemia there is a marked increase in unbound bilirubin, which can be toxic. The two methods traditionally used to treat hyperbilirubinemia are exchange transfusion and phototherapy. Each of these methods have drawbacks. The Department of Chemical, Bio, and Materials Engineering at Arizona State University is currently developing an extra-corporeal hemoperfusion column that will remove the unbound bilirubin fraction from the blood of jaundiced patients. This column utilizes coated ...


A Simple Staining Procedure For Quantifying Cell Adhesion In A Microtiter System, Stephen Schmechel Apr 1990

A Simple Staining Procedure For Quantifying Cell Adhesion In A Microtiter System, Stephen Schmechel

Life and Environmental Sciences Undergraduate Theses

The present study was designed to find a simple and effective staining technique to replace the tritiatedthymidine method in cell adhesion assays in 96-well microtiter plates. This method, a variation of previously used staining methods (Cardarelli and Pierschbacher, 1986; Barer, Lyon, and Draser, 1986), produced higher non-cellspecific background levels than the tritiated-thymidine method. But the staining method is useful for diverse cell types and the results attained through the staining technique were similar to those attained through the radiolabeling technique. The staining method produced reliable results in the screening of laminin and fibronectin peptides more quickly, less expensively, and less ...


A Point Mutation In The Cytoplasmic Domain Of The Transferrin Receptor Inhibits Endocytosis, Elvira Alvarez, Nuria Girones, Roger J. Davis Apr 1990

A Point Mutation In The Cytoplasmic Domain Of The Transferrin Receptor Inhibits Endocytosis, Elvira Alvarez, Nuria Girones, Roger J. Davis

Open Access Articles

The rate of receptor-mediated endocytosis of diferric 125I-transferrin by Chinese-hamster ovary cells expressing human transferrin receptors was compared with the rate measured for cells expressing hamster transferrin receptors. It was observed that the rate of endocytosis of the human transferrin receptor was significantly higher than that for the hamster receptor. In order to examine the molecular basis for the difference between the observed rates of endocytosis, a cDNA clone corresponding to the cytoplasmic domain of the hamster receptor was isolated. The predicted primary sequence of the cytoplasmic domain of the hamster transferrin receptor is identical with that of the human ...


Thermodynamic Extent Of Counterion Release Upon Binding Oligolysines To Single-Stranded Nucleic Acids., David Mascotti, Timothy Lohman Mar 1990

Thermodynamic Extent Of Counterion Release Upon Binding Oligolysines To Single-Stranded Nucleic Acids., David Mascotti, Timothy Lohman

David P. Mascotti

A major contribution to the binding free energy associated with most protein-nucleic acid complexes is the increase in entropy due to counterion release from the nucleic acid that results from electrostatic interactions. To examine this quantitatively, we have measured the thermodynamic extent of counterion release that results from the interaction between single-stranded homopolynucleotides and a series of oligolysines, possessing net charges z = 2-6, 8, and 10. This was accomplished by measuring the salt dependence of the intrinsic equilibrium binding constants--i.e., (delta log Kobs/delta log[K+])--over the range from 6 mM to 0.5 M potassium acetate. These ...


Nucleotide Sequence And Further Characterization Of The Synechococcus Sp. Strain Pcc 7002 Reca Gene: Complementation Of A Cyanobacterial Reca Mutation By The Escherichia Coli Reca Gene, R C. Murphy, G E. Gasparich, D A. Bryant, R D. Porter Jan 1990

Nucleotide Sequence And Further Characterization Of The Synechococcus Sp. Strain Pcc 7002 Reca Gene: Complementation Of A Cyanobacterial Reca Mutation By The Escherichia Coli Reca Gene, R C. Murphy, G E. Gasparich, D A. Bryant, R D. Porter

Gail Gasparich

The nucleotide sequence and transcript initiation site of the Synechococcus sp. strain PCC 7002 recA gene have been determined. The deduced amino acid sequence of the RecA protein of this cyanobacterium is 56% identical and 73% similar to the Escherichia coli RecA protein. Northern (RNA) blot analysis indicates that the Synechococcus strain PCC 7002 recA gene is transcribed as a monocistronic transcript 1,200 bases in length. The 5' endpoint of the recA mRNA was mapped by primer extension by using synthetic oligonucleotides of 17 and 27 nucleotides as primers. The nucleotide sequence 5' to the mapped endpoint contained sequence ...


Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick Jan 1990

Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick

Michael Sinensky

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic ...


Estuarine Studies : An Activities Text For Maine Schools, Education Division - Department Of Marine Resources Jan 1990

Estuarine Studies : An Activities Text For Maine Schools, Education Division - Department Of Marine Resources

Maine Collection

Estuarine Studies : An Activities Text for Maine Schools

Fisheries Education Unit #16 - Produced by The Education Division, Department of Marine Resources, State House Station 21, Augusta, Maine 04333-0021.

Revised 1990. Printed Under Appropriation No. 3140.3260.



Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick Jan 1990

Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick

Faculty Publications

The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic ...


Conformational And Circular Dichroism Studies On N-Acetyl-L-Prolyl-D-Alanyl-Methylamide, S. Ramaprasad Jan 1990

Conformational And Circular Dichroism Studies On N-Acetyl-L-Prolyl-D-Alanyl-Methylamide, S. Ramaprasad

Journal of the Arkansas Academy of Science

The compact ordered conformations of the molecule N-Acteyl-L-Prolyl-D-Alanyl-Methylamide have been studied by semiempirical energy calculations in vacuum and circular dichroism (CD) in solution. The presence of ordered structure has been observed in hydrogen bond promoting solvents like trifluoroethanol by CD studies. In hydrogen bond breaking solvents, like trifluoroacetic acid (TFA), significant fraction of the ordered conformers probably assume extended conformation without intramolecular hydrogen bonds and perhaps are in equilibrium with the fraction of compact ordered structures. The trend observed in going from nonpolar to polar solvent is also compatible with the previous NMR studies in solution. The semiempirical energy calculations ...


Mermithid Nematodes: Sem Observations Comparing Hexamethyldisilazane And Critical Point Drying Methods, William R. Bowen, Christopher C. Hemann, Arthur A. Johnson, Barry H. Good Jan 1990

Mermithid Nematodes: Sem Observations Comparing Hexamethyldisilazane And Critical Point Drying Methods, William R. Bowen, Christopher C. Hemann, Arthur A. Johnson, Barry H. Good

Journal of the Arkansas Academy of Science

Morphological features of mermithid nematodes (Mermithidae) were studied with scanning electron microscopy, using hexamethyldisilazane-air drying in comparison with critical point drying via liquid carbon dioxide. Although general morphologic preservation of both HMDS-dried and CP-dried specimens was similar, structural features of the complex cuticle and internal organization were more easily resolved at higher magnifications in the HMDS-dried nematodes. These features include the superficial cuticular annulations, the fibrillar inner cuticle and peg-like microtrabeculae. The previously undescribed microtrabeculae are of special interest since they may facilitate an interaction of the mermithid (and perhaps nameatodes in general) musculature with its body wall that, at ...


Rotational Symmetries Of Nuclear States: Spin Determinations In Advanced Laboratory, Wilfred J. Braithwaite Jan 1990

Rotational Symmetries Of Nuclear States: Spin Determinations In Advanced Laboratory, Wilfred J. Braithwaite

Journal of the Arkansas Academy of Science

An advanced laboratory experiment is described which shows the connection between the rotational symmetries of nuclear states and the assignments of spins to discrete nuclear states. Standard angular correlation methods were used to study the two sequential gamma ray transitions in each ⁶⁰Ni nucleus, populated by unobserved beta decays from a weak radioactive ⁶⁰Co source. The chosen electronics and detectors were inexpensive and easy to operate. This experiment was extended to introduce students to real-world data acquisition, using finite-geometry detectors, which resulted in enormously larger coincident data rates.


Molecular Biology Of Parasites Causing Tropical Diseases, John E Donelson Jan 1990

Molecular Biology Of Parasites Causing Tropical Diseases, John E Donelson

Presidential Lecture series

No abstract provided.


Computer Simulation Of Arterial Blood Flow , Nikolaos Stergiopulos Jan 1990

Computer Simulation Of Arterial Blood Flow , Nikolaos Stergiopulos

Retrospective Theses and Dissertations

Computer models have been widely used to simulate pressure and flow propagation in the arterial system. While experimentation involving the human arterial system is difficult and impractical, computer models offer an attractive alternative for the study of arterial hemodynamics. The purpose of the present study was to develop a computer model of the whole systemic circulation and to use this model to study pressure and flow propagation under normal flow conditions, as well as under conditions of arterial disease;The mathematical model used to describe flow in an arterial segment was based on the one-dimensional continuity and momentum equations. The ...


Excited State Structure, Energy And Electron Transfer Dynamics Of Photosynthetic Reaction Centers: A Hole Burning Study , Deming Tang Jan 1990

Excited State Structure, Energy And Electron Transfer Dynamics Of Photosynthetic Reaction Centers: A Hole Burning Study , Deming Tang

Retrospective Theses and Dissertations

The excited state structure, early time energy and electron transfer dynamics for bacterial photosynthetic reaction centers of Rhodoseudomonas viridis, Rhodobacter sphaeroides and green plant photosynthetic reaction center of Photosystem II (PS II) have been determined by hole burning spectroscopy. Transient hole burned spectra of the bacterial reaction centers reveal a special pair Franck-Condon marker mode progression with a superimposed zero phonon hole. Such progression is found to be absent in green plant Photosystem II which raises the question of structural similarities between the PS II and bacterial reaction centers. The excited state decay times are obtained for all systems and ...