71 research outputs found
Synthesis, characterization, and electrochemical behavior of (5,10,15-tri-X-phenyl-2,3,7,8,12,13,17,18-octamethylcorrolato)cobalt(III) triphenylphosphine complexes, where X = p-OCH3, p-CH3, p-Cl, m-Cl, o-Cl, m-F, o-F, or H
No full textComplexes of (5,10,15-tri-X-phenyl-2,3,7,8,12,13,17,18-octamethylcorrolato)cobalt(III) triphenylphosphine, (OMTXPC)Co(PPh(3)), where X = p-OCH3, p-CH3, p-Cl, m-Cl, m-F, o-Cl, o-F, or H, were synthesized and characterized in nonaqueous media using electrochemical, spectroelectrochemical, and EPR techniques. The o-Cl derivative exists as different atropisomers in solution, and a thermal interconversion between them was achieved at 338 K in toluene. Activation parameters (Delta S-double dagger, Delta H-double dagger) for interconversion between the atropisomers were obtained from H-1 NMR measurements and were similar in magnitude to values reported for ortho-substituted tetraphenylporphyrin derivatives. Formation constants for pyridine binding to the pentacoordinate cobalt(III) corroles in benzene were obtained from W-visible spectrophotometric measurements and ranged between 20 and 193 M(-1), with the exact value depending upon the specific electron-donating or electron-withdrawing group on the three phenyl rings of the complex. The redox potentials of (OMTXPC)Co(PPh(3)) also shift with the nature of the phenyl ring substituents, and linear free-energy relationships are observed. Each cobalt(III) derivative undergoes two one-electron reductions, the first of which involves a Co(III)/Co(II) conversion add concomitant loss of the bound PPh(3) ligand. Four one-electron oxidations; are also observed for the investigated compounds, and this contrasts with the oxidative properties of related cobalt(II) porphyrins which undergo a maximum of three one-electron oxidations under similar solution conditions. The first one-electron oxidation of each cobalt(III) corrole is metal-centered and results in formation of a Co(IV) corrole as ascertained by EPR spectroscopic characterization of the electrogenerated species
Creating and Sustaining a Democratic Classroom in the Presence of Market Ideology
No full textABSTRACT\ud
CREATING AND SUSTAINING A DEMOCRATIC CLASSROOM IN\ud
THE PRESENCE OF MARKET IDEOLOGY\ud
by\ud
?? Annie S. Adamian 2010\ud
Master of Arts in Education\ud
Curriculum and Instruction Option\ud
California State University, Chico\ud
Spring 2010\ud
Equitable learning environments that empower, enlighten and promote lifelong\ud
learning for all students are rare in today???s American public schools. Addressing\ud
the need for a forum in which students begin to gain knowledge by the means of critical\ud
pedagogy has been silenced and dominated by the rigid discourse driven by market ideology.\ud
High stakes testing sustained through sanctions and incentives are promoting a\ud
culture of schooling which deems knowledge as a means to an end. In order for equitable\ud
learning environments to become a reality, democratic practice needs to come alive\ud
in the classroom. This study explores the ways to create and sustain an equitable learning\ud
environment by means of democratic practice. The author employs action research,\ud
using both qualitative and quantitative measures, and develops meaningful insight into\ud
how democratic practice can coexist within the context of market ideology. Seeking\ud
xi\ud
balance between the public (social reconstruction ideology) and private (market ideology)\ud
purposes of schooling was the foundation of this study. This study provided an emic\ud
perspective into four seventh grade life science classrooms. By linking theory and practice\ud
(praxis), action was taken to meet the needs of all learners, and the results show that\ud
it is possible to teach democratically in a system that is driven by market ideology.CSU, Chic
Attentional Enhancement of Tracked Stimuli in Early Visual Cortex Has Limited Capacity
No full textFunding Information: Received Mar. 28, 2022; revised Sep. 22, 2022; accepted Sep. 26, 2022. Author contributions: N.A. and S.K.A. designed research; N.A. and S.K.A. performed research; S.K.A. contributed unpublished reagents/analytic tools; N.A. analyzed data; N.A. wrote the first draft of the paper; N.A. and S.K.A. edited the paper; N.A. and S.K.A. wrote the paper. This work was supported by the Biotechnology and Biological Sciences Research Council Grant BB/ P002404/1 (to S.K.A.) and the Leverhulme Early Career Fellowship ECF-2020-488 (to N.A.). We thank Alex O. Holcombe and Christian Merkel for their many insightful comments and suggestions. We also thank Rafael Lemarchand for his help in data collection. The authors declare no competing financial interests. Correspondence should be addressed to Nika Adamian at [email protected] reviewe
Retinitis Pigmentosa GTPase Regulator (RPGR) protein isoforms in mammalian retina:insights into X-linked Retinitis Pigmentosa and associated ciliopathies
No full textMutations in the cilia-centrosomal protein Retinitis Pigmentosa GTPase Regulator (RPGR) are a frequent cause of retinal degeneration. The RPGR gene undergoes complex alternative splicing and encodes multiple protein isoforms. To elucidate the function of major RPGR isoforms (RPGR 1-19 and RPGR ORF15), we have generated isoform-specific antibodies and examined their expression and localization in the retina. Using sucrose-gradient centrifugation, immunofluorescence and co-immunoprecipitation methods, we show that RPGR isoforms localize to distinct sub-cellular compartments in mammalian photoreceptors and associate with a number of cilia-centrosomal proteins. The RCC1-like domain of RPGR, which is present in all major RPGR isoforms, is sufficient to target it to the cilia and centrosomes in cultured cells. Our findings indicate that multiple isotypes of RPGR may perform overlapping yet somewhat distinct transport-related functions in photoreceptors
Ways to produce new superheavy isotopes with Z=111–117 in charged particle evaporation channels
No full textAbstractThe excitation functions of the production of new heaviest isotopes of superheavy nuclei with charge numbers 111–117 in the pxn and αxn evaporation channels of the 48Ca-induced hot fusion reactions are predicted for the first time for future experiments
Possible origin of transition from symmetric to asymmetric fission
No full textAbstractThe charged distributions of fragments produced in the electromagnetic-induced fission of the even–even isotopes of Rn, Ra, Th, and U are described within an improved scission-point model and compared with the available experimental data. The three-equal-peaked charge distributions are predicted for several fissioning nuclei with neutron number N=136. The possible explanation of the transition from a symmetric fission mode to an asymmetric one around N∼136 is presented. The excitation energy dependencies of the asymmetric and symmetric fission modes are anticipated
Profile Attractiveness in Borderline Class III Surgical/Orthodontic Cases
No full textIntroduction: This study evaluated differences between laypersons and orthodontists in rating facial attractiveness in borderline class III surgical/orthodontic cases. The purpose was to determine whether orthognathic surgery or camouflage is a better alternative for observable esthetic improvement in borderline Class III surgical/orthodontic patients. This study will aid the orthodontist in recommending treatment options to enhance profile attractiveness of borderline Class III surgical/orthodontic patients. Materials and Methods: Thirty profile images of treated borderline class III surgical/orthodontic cases were selected. Fifteen of the profile images were of cases that had been treated by orthodontics alone, and fifteen images were of cases that had been treated by a combination of orthodontics and surgery. Profile images were modified in Photoshop to mask the face and eyes. Patients selected for this study: 1) were 16-25 years of age, 2) had a half-step or more Class III molar relationship, 3) had a pretreatment ANB greater than -4° and less than 1°, and 4) had a Wits appraisal less than -1.5mm and greater than -4mm. Patients with craniofacial anomalies and skin conditions were excluded from this study. Two groups of thirty raters evaluated the profile images for facial attractiveness by marking a 10 cm visual analog scale. One group of raters was composed of thirty orthodontists and the other group was composed of thirty laypersons. In order to evaluate intra-individual reproducibility of the measuring system, ten duplicate sets of profile images were added to the series. Results: The repeated measures ANOVA F-test results found a statistically significant difference between facial attractiveness scores (p = 0.000), with higher ratings by orthodontists. There was no statistically significant difference between treatment type (p = 0.278). Intraclass correlation results indicate excellent reliability. The ICC was 0.774 (95% CI; 0.733, 0.808). The level of significance was set at α = .05. Conclusions: In evaluating facial attractiveness of borderline Class III surgical/orthodontic cases, laypersons are more critical than orthodontists. Furthermore, surgery or camouflage treatment provides similar esthetic improvement in profile attractiveness in borderline class III surgical/orthodontic patients
Physical origin of the transition from symmetric to asymmetric fission fragment charge distribution
No full textInferring Functional Relationships of Proteins from Local Sequence and Spatial Surface Patterns
No full textes, and for further inquiries on evolutionary origins of structural elements important for protein function. q 2003 Elsevier Ltd. All rights reserved. Keywords: protein surface; surface pattern; protein function; pocket sequence; pocket shape *Corresponding author Introduction With rapid progress in the determination of protein structures, 1,2 protein structural analysis has become an important source of information for understanding functional roles of proteins. Conservation of protein structures often reveals very distant evolutionary relationships, which are otherwise difficult to detect by sequence analysis alone. Analysis of protein structure can provide insightful ideas about the biochemical functions and mechanisms of proteins (e.g. active sites, catalytic residues, and substrate interactions). 9--11 An important approach of studying protein structures is fold analysis. Identifying the correct tertiary fold of protein is often helpful for inferring protein func
Adjusting the Structure of 2′-Modified Nucleosides and Oligonucleotides via C4′-α‑F or C4′-α-OMe Substitution: Synthesis and Conformational Analysis
No full textWe
report the first syntheses of three nucleoside analogues, namely,
2′,4′-diOMe-rU, 2′-OMe,4′-F-rU, and 2′-F,4′-OMe-araU,
via stereoselective introduction of fluorine or methoxy functionalities
at the C4′-α-position of a 4′,5′-olefinic
intermediate. Conformational analyses of these nucleosides and comparison
to other previously reported 2′,4′-disubstituted nucleoside
analogues make it possible to evaluate the effect of fluorine and
methoxy substitution on the sugar pucker, as assessed by NMR, X-ray
diffraction, and computational methods. We found that C4′-α-F/OMe
substituents reinforce the C3′-endo (north) conformation of 2′-OMe-rU. Furthermore, the predominant
C2′-endo (south/east) conformation
of 2′-F-araU switches to C3′-endo upon introduction
of these substituents at C4′. The nucleoside analogues were
incorporated into DNA and RNA oligonucleotides via standard phosphoramidite
chemistry, and their effects on the thermal stability of homo- and
heteroduplexes were assessed via UV thermal melting experiments. We
found that 4′-substituents can modulate the binding affinity
of the parent 2′-modified oligomers, inducing a mildly destabilizing
or stabilizing effect depending on the duplex type. This study expands
the spectrum of oligonucleotide modifications available for rational
design of oligonucleotide therapeutics
- …
