Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 13 of 13
Full-Text Articles in Life Sciences
Nicholas Reactions In The Construction Of Cyclohepta[De]Naphthalenes And Cyclohepta[De]Naphthalenones. The Total Synthesis Of Microstegiol, Rafiq Taj, James R. Green
Nicholas Reactions In The Construction Of Cyclohepta[De]Naphthalenes And Cyclohepta[De]Naphthalenones. The Total Synthesis Of Microstegiol, Rafiq Taj, James R. Green
Chemistry and Biochemistry Publications
The application of the Nicholas reaction chemistry of 2,7-dioxygenated naphthalenes in the synthesis of cyclohepta[de]napthalenes and in the synthesis of (±)-microstegiol (1) is presented. The substitution profile of Nicholas monosubstitution (predominantly C-1) and disubstitution reactions (predominantly 1,6-) on 2,7-dioxygenated napthalenes is reported. Application of a 1,8-dicondensation product and selected C-1 monocondensation products to the construction of cyclohepta[de]naphthalenes by way of ring closing metathesis and intramolecular Friedel−Crafts reactions, respectively, is described. Deprotection of the C-7 oxygen function to the corresponding naphthol allows tautomerization to cyclohepta[de]naphthalene-1-ones upon seven-membered-ring closure in most cases, and replacement …
Intramolecular Nicholas Reactions In The Synthesis Of Dibenzocycloheptanes. Synthesis Of Allocolchicine Nsc 51046 And Analogues And The Formal Synthesis Of (−)-Allocolchicine, Sinisa Djurdjevic, Fei Yang, James R. Green
Intramolecular Nicholas Reactions In The Synthesis Of Dibenzocycloheptanes. Synthesis Of Allocolchicine Nsc 51046 And Analogues And The Formal Synthesis Of (−)-Allocolchicine, Sinisa Djurdjevic, Fei Yang, James R. Green
Chemistry and Biochemistry Publications
The preparation of dibenzocycloheptyne-Co2(CO)6 complexes by intramolecular Nicholas reactions of biaryl-2-propargyl alcohol-Co2(CO)6 derivatives is described. Reductive decomplexation of the dibenzocycloheptyne-Co2(CO)6 complexes affords the corresponding dibenzocycloheptenes, individual members of which have been employed in a formal total synthesis of (−)-allocolchicine, the preparation of 6,7-dihydro-3,4,9,10,11-pentamethoxy-5H-dibenzo[a,c]cyclohepten-5-one, and the enantioselective total syntheses of NSC 51046 and its 3,8,9,10-tetramethoxy regioisomer.
A Novel Neural Substrate For The Transformation Of Olfactory Inputs Into Motor Output, Dominique Derjean, Aimen Moussaddy, Elias Atallah, Melissa St-Pierre, François Auclair, Steven Chang, Xiang Ren, Barbara Zielinski, Réjean Dubuc
A Novel Neural Substrate For The Transformation Of Olfactory Inputs Into Motor Output, Dominique Derjean, Aimen Moussaddy, Elias Atallah, Melissa St-Pierre, François Auclair, Steven Chang, Xiang Ren, Barbara Zielinski, Réjean Dubuc
Biological Sciences Publications
Anatomical and physiological experiments in the lamprey reveal the neural circuit involved in transforming olfactory inputs into motor outputs, which was previously unknown in a vertebrate.
A Quantitative Description Of The Vocalizations And Vocal Activity Of The Barred Owl, Karan J. Odom, Daniel J. Mennill
A Quantitative Description Of The Vocalizations And Vocal Activity Of The Barred Owl, Karan J. Odom, Daniel J. Mennill
Biological Sciences Publications
Barred Owls (Strix varia) are highly vocal and perform a diverse array of vocalizations. They are often monitored by acoustic surveys, yet Barred Owl vocalizations and vocal behavior are poorly described. We present a detailed analysis of Barred Owl vocal behavior with four goals: (1) to provide a quantitative description of Barred Owl vocalizations, including those given within duets, (2) to examine diel variation in vocal output for multiple vocalizations, (3) to explore the use of vocalizations inside and outside of duets, and (4) to identify sex-specific vocal characteristics and discuss their utility in identifying an owl's sex. Adult Barred …
Environmental Factors Associated With Reproductive Barrier Breakdown In Sympatric Trout Populations On Vancouver Island, Daniel D. Heath, Cory M. Bettles, Derek Roff
Environmental Factors Associated With Reproductive Barrier Breakdown In Sympatric Trout Populations On Vancouver Island, Daniel D. Heath, Cory M. Bettles, Derek Roff
Biological Sciences Publications
The incidence of hybridization between coastal cutthroat (Oncorhynchus clarki clarki) and rainbow trout (Oncorhynchus mykiss) varies widely among populations. The breakdown of reproductive isolation is of concern to managers, and raises the question: how have the two species retained their genetic and morphological divergence? Using a combination of mitochondrial DNA and nuclear DNA markers coupled with watershed attribute and disturbance data, we determined the distribution and frequency of trout hybridization on Vancouver Island, BC and the environmental factors associated with the hybridization. We found 284 hybrids (among 1004 fish) in 29 of 36 sampled populations. High variation in levels of …
The Hippo Tumor Suppressor Pathway Regulates Intestinal Stem Cell Regeneration, Phillip Karpowicz, Jessica Perez, Norbert Perrimon
The Hippo Tumor Suppressor Pathway Regulates Intestinal Stem Cell Regeneration, Phillip Karpowicz, Jessica Perez, Norbert Perrimon
Biological Sciences Publications
Skip to Next Section Identification of the signaling pathways that control the proliferation of stem cells (SCs), and whether they act in a cell or non-cell autonomous manner, is key to our understanding of tissue homeostasis and cancer. In the adult Drosophila midgut, the Jun N-Terminal Kinase (JNK) pathway is activated in damaged enterocyte cells (ECs) following injury. This leads to the production of Upd cytokines from ECs, which in turn activate the Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) pathway in Intestinal SCs (ISCs), stimulating their proliferation. In addition, the Hippo pathway has been recently implicated in …
Interleukin-6 Increases Expression And Secretion Of Cathepsin B By Breast Tumor-Associated Monocytes., Mona M. Mohamed, Dora Cavallo-Medved, Deborah Rudy, Arulselvi Anbalagan, Bonnie F. Sloane, Kamir Moin
Interleukin-6 Increases Expression And Secretion Of Cathepsin B By Breast Tumor-Associated Monocytes., Mona M. Mohamed, Dora Cavallo-Medved, Deborah Rudy, Arulselvi Anbalagan, Bonnie F. Sloane, Kamir Moin
Biological Sciences Publications
In the tumor microenvironment, monocytes respond to paracrine stimuli from breast cancer cells by secreting molecules that participate in breast cancer growth, invasion, intravasation and metastasis. Here we examined the effects of media conditioned by MDA-MB-231 human breast carcinoma cells (231-CM) on expression and secretion of proteases and secretion of cytokines by U937 human monocytes. We found that 231-CM increased U937: 1) proliferation; 2) expression, activity and secretion of the cysteine protease cathepsin B (CTSB); 3) secretion of matrix metalloproteinases (MMP)-2 and -9; and 4) secretion of interleukin-6 (IL-6) and insulin-like growth factor binding protein-1 (IGFBP-1). We further demonstrated by …
Geographic Variation In Sperm Traits Reflects Predation Risk And Natural Rates Of Multiple Paternity In The Guppy, K. E. Elgee, J. P. Evans, I. W. Ramnarine, S. A. Rush, Trevor E. Pitcher
Geographic Variation In Sperm Traits Reflects Predation Risk And Natural Rates Of Multiple Paternity In The Guppy, K. E. Elgee, J. P. Evans, I. W. Ramnarine, S. A. Rush, Trevor E. Pitcher
Great Lakes Institute for Environmental Research Publications
Guppies (Poecilia reticulata) are models for understanding the interplay between natural and sexual selection. In particular, predation has been implicated as a major force affecting female sexual preferences, male mating tactics and the level of sperm competition. When predation is high, females typically reduce their preferences for showy males and engage more in antipredator behaviours, whereas males exploit these changes by switching from sexual displays to forced matings. These patterns are thought to account for the relatively high levels of multiple paternity in high-predation populations compared to low-predation populations. Here, we assess the possible evolutionary consequences of these patterns by …
Comparing Methods Of Quantifying Tibial Acceleration Slope, Adriana Duquette, David M. Andrews
Comparing Methods Of Quantifying Tibial Acceleration Slope, Adriana Duquette, David M. Andrews
Human Kinetics Publications
Considerable variability in tibial acceleration slope (AS) values, and different interpretations of injury risk based on these values, have been reported. Acceleration slope variability may be due in part to variations in the quantification methods used. Therefore, the purpose of this study was to quantify differences in tibial AS values determined using end points at various percentage ranges between impact and peak tibial acceleration, as a function of either amplitude or time. Tibial accelerations were recorded from 20 participants (21.8 ± 2.9 years, 1.7 m ± 0.1 m, 75.1 kg ± 17.0 kg) during 24 unshod heel impacts using a …
Perceptions Of Cohesion By Youth Sport Participants, Mark Eys, Todd M. Loughead, Steven R. Bray, Albert V. Carron
Perceptions Of Cohesion By Youth Sport Participants, Mark Eys, Todd M. Loughead, Steven R. Bray, Albert V. Carron
Human Kinetics Publications
Cohesion is an important small group variable within sport. However, the conceptualization and examination of cohesion have predominately been oriented toward adult populations. The purpose of the current study was to garner an understanding of what cohesion means to youth sport participants. Fifty-six team sport athletes (M age = 15.63 ± 1.01 years) from two secondary schools took part in focus groups designed to understand participants’ perceptions of (a) the definition of cohesion and indicators of cohesive and noncohesive groups and (b) methods used to attempt to develop cohesion in their groups. Overall, the responses to part (a) yielded 10 …
The Effectiveness Of Wrist Guards For Reducing Wrist And Elbow Accelerations Resulting From Simulated Forward Falls, Timothy A. Burkhart, David M. Andrews
The Effectiveness Of Wrist Guards For Reducing Wrist And Elbow Accelerations Resulting From Simulated Forward Falls, Timothy A. Burkhart, David M. Andrews
Human Kinetics Publications
The effectiveness of wrist guards and modifying elbow posture for reducing impact-induced accelerations at the wrist and elbow, for the purpose of decreasing upper extremity injury risk during forward fall arrest, has not yet been documented in living people. A seated human pendulum was used to simulate the impact conditions consistent with landing on outstretched arms during a forward fall. Accelerometers measured the wrist and elbow response characteristics of 28 subjects following impacts with and without a wrist guard, and with elbows straight or slightly bent. Overall, the wrist guard was very effective, with significant reductions in peak accelerations at …
Full-Court Quest: The Girls From Fort Shaw Indian School, Basketball Champions Of The World, Victoria Paraschak
Full-Court Quest: The Girls From Fort Shaw Indian School, Basketball Champions Of The World, Victoria Paraschak
Human Kinetics Publications
No abstract provided.
The Relationship Among Athlete Leadership Behaviors And Cohesion In Team Sports, Diana Vincer, Todd M. Loughead
The Relationship Among Athlete Leadership Behaviors And Cohesion In Team Sports, Diana Vincer, Todd M. Loughead
Human Kinetics Publications
This study examined the influence of athlete leadership behaviors on perceptions of team cohesion. The participants were 312 athletes from 25 varsity and club level teams. Each participant completed the Group Environment Questionnaire (Carron, Widmeyer, & Brawley, 1985) that assessed cohesion and the Leadership Scale for Sports (Chelladurai & Saleh, 1980) that assessed athlete leadership behaviors. Overall, it was found that individual perceptions of Training and Instruction, and Social Support positively influenced all four dimensions of cohesion (ATG-T, ATG-S, GI–T, GI-S). Furthermore, Autocratic Behavior was negatively associated with the four dimensions of cohesion. Finally, Democratic Behavior was positively related to …