gebhart/patrepeval huggingface dataset:
Transition-metal-promoted reactions of boron hydrides. 9. Cp*Ir-catalyzed reactions of polyhedral boranes and acetylenes (1988)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTransition-metal-promoted reactions of boron hydrides. 9. Cp*Ir-catalyzed reactions of polyhedral boranes and acetylenesMario G. L. Mirabelli and Larry G. SneddonCite this: J. Am. Chem. Soc. 1988, 110, 2, 449–453Publication Date (Print):January 1, 1988Publication History Published online1 May 2002Published inissue 1 January 1988https://pubs.acs.org/doi/10.1021/ja00210a023https://doi.org/10.1021/ja00210a023research-articleACS PublicationsRequest reuse permissionsArticle Views685Altmetric-Citations124LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
Efficient Immunization and Cross-Priming by Vaccine Adjuvants Containing TLR3 or TLR9 Agonists Complexed to Cationic Liposomes (2006)

Complexing TLR9 agonists such as plasmid DNA to cationic liposomes markedly potentiates their ability to activate innate immunity. We therefore reasoned that liposomes complexed with DNA or other TLR agonists could be used as effective vaccine adjuvants. To test this hypothesis, the vaccine adjuvant effects of liposomes complexed to TLR agonists were assessed in mice. We found that liposomes complexed to nucleic acids (liposome-Ag-nucleic acid complexes; LANAC) were particularly effective adjuvants for eliciting CD4(+) and CD8(+) T cell responses against peptide and protein Ags. Notably, LANAC containing TLR3 or TLR9 agonists effectively cross-primed CD8(+) T cell responses against even low doses of protein Ags, and this effect was independent of CD4(+) T cell help. Ag-specific CD8(+) T cells elicited by LANAC adjuvants were functionally active and persisted for long periods of time in tissues. In a therapeutic tumor vaccine model, immunization with the melanoma peptide trp2 and LANAC adjuvant controlled the growth of established B16 melanoma tumors. In a prophylactic vaccine model, immunization with the Mycobacterium tuberculosis protein ESAT-6 with LANAC adjuvant elicited significant protective immunity against aerosol challenge with virulent M. tuberculosis. These results suggest that certain TLR agonists can be combined with cationic liposomes to produce uniquely effective vaccine adjuvants capable of eliciting strong T cell responses against protein and peptide Ags.
Self-Assembly of Peptide−Amphiphile Nanofibers:  The Roles of Hydrogen Bonding and Amphiphilic Packing (2006)

The role of hydrogen bonding and amphiphilic packing in the self-assembly of peptide-amphiphiles (PAs) was investigated using a series of 26 PA derivatives, including 19 N-methylated variants and 7 alanine mutants. These were studied by circular dichroism spectroscopy, a variety of Fourier transform infrared spectroscopies, rheology, and vitreous ice cryo-transmission electron microscopy. From these studies, we have been able to determine which amino acids are critical for the self-assembly of PAs into nanofibers, why the nanofiber is favored over other possible nanostructures, the orientation of hydrogen bonding with respect to the nanofiber axis, and the constraints placed upon the portion of the peptide most intimately associated with the biological environment. Furthermore, by selectively eliminating key hydrogen bonds, we are able to completely change the nanostructure resulting from self-assembly in addition to modifying the macroscopic mechanical properties associated with the assembled gel. This study helps to clarify the mechanism of self-assembly for peptide amphiphiles and will thereby help in the design of future generations of PAs.
Polysaccharide-Based Hydrogels: Preparation, Characterization, and Drug Interaction Behaviour (2008)

Oxidized alginate (ADA) and oxidized alginate blended with chitosan (ADA-Chit) were prepared in the presence of borax and CaCl 2, and their interactions with an antifolate drug, pyrimethamine (PYR), have been investigated. Tablets with a mean diameter of 1.2 +/- 0.06 cm were produced and drug interactions were performed in dimethyl sulfoxide (DMSO) using isothermal titration calorimetry (ITC). From ITC responses, the enthalpy changes of interaction PYR/materials, Delta int H, have been determined and were found to be -11.73 +/- 0.517 kJ mol (-1) for ADA and -4.86 +/- 0.156 kJ mol (-1) for ADA-Chit. The PYR encapsulation of approximately 75% was achieved for both materials, as measured by UV spectrometer.
Identification and characterization of a ouabain-like compound from human plasma. (1991)

The plasma membrane sodium-potassium pumps that regulate intracellular sodium in most animal cells have specific, high-affinity receptors for the digitalis glycosides and their aglycones. This has fostered speculation that there is an endogenous ligand. We have purified and structurally identified by mass spectroscopy an endogenous substance from human plasma that binds with high affinity to this receptor and that is indistinguishable from the cardenolide ouabain. This human ouabain-like compound (OLC) displaces [3H]ouabain from its receptor, inhibits Na,K-ATPase and ouabain-sensitive 86Rb+ uptake, and has cardiotonic actions quantitatively similar to commercial ouabain. Immunoreactive OLC was detected in the plasma of many mammals, and high concentrations were found in the adrenals. The circulating OLC may modulate intracellular Na+ and affect numerous Na+ gradient-dependent processes including intracellular Ca2+ and pH homeostasis in many tissues. Furthermore, altered circulating levels of OLC may be associated with the pathogenesis of certain forms of hypertension.
Regulation of Both Erythroid and Megakaryocytic Differentiation of a Human Leukemia Cell Line, UT-7 (1998)

UT-7 is a human megakaryoblastic leukemia cell line with absolute dependence on interleukin-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), or erythropoietin (EPO) for growth and survival. Among its sublines, UT-7/GM, which remains undifferentiated in the presence of GM-CSF, has a bipotency showing differentiation into erythroid or megakaryocytic cell lineages in the presence of EPO or thrombopoietin (TPO), respectively. To investigate the mechanism underlying determination of cell differentiation, we investigated the role of signal transducers and activators of transcription (STAT) in EPO-induced erythroid differentiation. UT-7 cells grow in response to GM-CSF and EPO but do not differentiate into mature cells. UT-7/GM cells grow in response to GM-CSF and differentiate into erythroid cells by EPO. In UT-7 cells, both GM-CSF and EPO induced the activation of Stat1 alpha, Stat3 and Stat5. In UT-7/GM cells, EPO activated Stat5 alone, although the activation of Stat1 alpha, Stat3, and Stat5 was induced by GM-CSF or TPO. In addition, GM-CSF inhibited EPO-induced erythroid differentiation and concomitantly activated Stat1 alpha and Stat3 in UT-7/GM cells even in the presence of EPO. Further we transfected Stat1 alpha, Stat3 cDNA or both into UT-7/GM cells. Hemoglobin-positive cells were decreased in the stable transfectants stimulated with EPO. These results indicate that Stat1 alpha and Stat3 have an inhibitory effect on the EPO-induced erythroid differentiation, and more complicated combination of transcription factors may play an important role in the decision of cell differentiation.
Improving correctness and failure handling in workflow management systems (1998)

A workflow management system (WFMS) facilitates the coordinated execution of applications (steps) that comprise a business process (workflow) across distributed nodes. State-of-the-art WFMSs do not have adequate support for handling various correctness and failure handling requirements of workflows. Different correctness requirements arise due to the dependencies between steps that access shared resources. Failure of steps in a workflow and system failures can cause data inconsistencies if handled improperly. Scalability is also a problem in current WFMSs since they use a centralized workflow control architecture that can easily become a performance bottleneck. In this thesis, we have developed the concepts and infrastructure necessary to address the above issues. To handle dependencies across workflows we have developed techniques for expressing and handling mutual-exclusion, relative ordering and rollback dependency requirements across workflow instances. To handle failure of steps within a workflow, we have proposed a new opportunistic scheme that avoids unnecessary compensations and re-executions when workflows are rolled back partially and re-executed. To handle system failures we have designed suitable logging schemes and protocols. To achieve scalability while satisfying the different correctness and failure handling requirements, we have enhanced our techniques to work on parallel and distributed workflow control architectures. To realize the above concepts, we have designed a workflow specification language, a two stage compiler and a rule-based run-time system. A workflow designer specifies the workflow schema and the resources accessed by the steps from a global database of resources. The two stage workflow compiler determines data dependencies and translates the high level schema into a uniform set of rules. The run-time system interprets these rules and executes the workflows in accordance with their requirements under central, parallel and distributed workflow control. To demonstrate the usefulness and practicality of our approach, we have implemented a prototype system that can offer better correctness, performance and functionality than state-of-the-art WFMSs.
The Effects of Hairpin Loops on Ligand−DNA Interactions (2009)

Hairpin nucleic acids are frequently used in physical studies due to their greater thermal stability compared to their equivalent duplex structures. They are also good models for more complex loop-containing structures such as quadruplexes, i-motifs, cruciforms, and molecular beacons. Although a connecting loop can increase stability, there is little information on how the loop influences the interactions of small molecules with attached base-paired nucleic acid regions. In this study, the effects of different hairpin loops on the interactions of A/T specific DNA minor groove binding agents with a common stem sequence have been investigated by spectroscopic and surface plasmon resonance (SPR) biosensor methods. The results indicate that the hairpin loop has little influence on the specific site interactions on the stem but significantly affects nonspecific binding. The use of a non-nucleotide loop (with a reduced negative charge) not only enhances the thermal stability of the hairpin but also reduces the nonspecific binding at the loop without compromising the primary binding affinity on the stem.
Unraveling the High Uptake and Selectivity of CO2 in the Zeolitic Imidazolate Frameworks ZIF-68 and ZIF-69 (2010)

Understanding the CO2 adsorption mechanism of zeolitic imidazole frameworks (ZIFs) is the key to improving the adsorption ability of new metal–organic framework materials for gas capture applications and designing novel frameworks. In this work, the ONIOM2(B3LYP/6-31G**:UFF) method is used to investigate the interactions between CO2 and CO molecules with ZIF-68 and ZIF-69, respectively. Calculation results indicate that a strong Lewis acid–base interaction exists between the gas molecules and nitro groups of 2-nitroimidazole linkers, which thus prevents the entry of gas molecules into the small pores of ZIFs. The simultaneous interaction of both oxygen atoms of CO2 with the H atoms of the benzimidazole (5-chlorobenzimidazole) rings in the large pores results in the high CO2 selectivity observed for both ZIFs. The presence of electron-withdrawing groups in the phenylimidazole linker of ZIF increases the interaction between the oxygen atoms of CO2 and hydrogen atoms of the phenyl rings in its large pores. This work elucidates the adsorption mechanism of CO2 and CO to ZIFs at the molecular level and provides useful information for the design of MOFs in gas purification and separation applications.
A potent transrepression domain in the retinoblastoma protein induces a cell cycle arrest when bound to E2F sites. (1995)

An intact T/E1A-binding domain (the pocket) is necessary, but not sufficient, for the retinoblastoma protein (RB) to bind to DNA-protein complexes containing E2F and for RB to induce a G1/S block. Indirect evidence suggests that the binding of RB to E2F may, in addition to inhibiting E2F transactivation function, generate a complex capable of functioning as a transrepressor. Here we show that a chimera in which the E2F1 transactivation domain was replaced with the RB pocket could, in a DNA-binding and pocket-dependent manner, mimic the ability of RB to repress transcription and induce a cell cycle arrest. In contrast, a transdominant negative E2F1 mutant that is capable of blocking E2F-dependent transactivation did not. Fusion of the RB pocket to a heterologous DNA-binding domain unrelated to E2F likewise generated a transrepressor protein when scored against a suitable reporter. These results suggest that growth suppression by RB is due, at least in part, to transrepression mediated by the pocket domain bound to certain promoters via E2F.
Clinical Pharmacology of Leukotriene Receptor Antagonists and 5-Lipoxygenase Inhibitors (1998)

Blinded, randomized, and placebo-controlled clinical trials have established that cysteinyl leukotriene (cysLT) receptor antagonists and 5-lipoxygenase (5-LO) inhibitors are safe and effective asthma treatments. Trials of 13- to 26-wks' duration demonstrate that both the cysLT1 receptor antagonist, zafirlukast, and the 5-LO inhibitor, zileuton, improve pulmonary function and decrease daytime and nocturnal symptoms. Concomitant rescue beta-agonist inhaler use and the need for corticosteroid rescue are also reduced. Preliminary studies suggest that antileukotriene agents may also reduce indices of airway inflammation, including inflammatory cell counts and airway hyperresponsiveness. Both cysLT1 antagonists and 5-LO inhibitors offer a new approach to asthma management. Drazen J. Clinical pharmacology of leukotriene receptor antagonists and 5-lipoxygenase inhibitors.
An Unusual Trifluoromethyl Elimination Reaction from the 4,4-Bis(trifluoromethyl)-5-hydroxyimidazoline Ring System (1997)

A facile detrifluoromethylation was observed when 4,4-bis(trifluoromethyl)-5-hydroxyimidazoline 5 was treated with a variety of bases to afford the biologically interesting 4-(trifluoromethyl)imidazole analogs (9 and 10). A unique mechanism was proposed for this transformation, supported by isolating and trapping the hypothesized intermediates. Heating of 5 with Et(4)NCN in DMSO provided 19, which was clearly derived from the proposed intermediate 17. Finally, imidazole 9 was converted into the N-[2-phenyl-4-(trifluoromethyl)-1H-imidazol-5-yl]-N-methylbenzamide analogs, which were potential acyl CoA:cholesterol acyltransferase (ACAT) inhibitors.
Mesenchymal stem cells used for rabbit tendon repair can form ectopic bone and express alkaline phosphatase activity in constructs (2004)

Mesenchymal stem cells (MSCs) have been used to repair connective tissue defects in several animal models. Compared to "natural healing" controls (no added cells), MSC-collagen gel constructs in rabbit tendon defects significantly improve repair biomechanics. However, ectopic bone forms in 28% of MSC-treated rabbit tendons. To understand the source of bone formation, three studies were performed. In the first study, the hypothesis was tested that MSCs delivered during surgery contribute to bone formation in the in vivo repair site. Adjacent histological sections in the MSC-treated repair tissue were examined for pre-labeled MSCs and for cells showing positive alkaline phosphatase (ALP) activity. Both cells were observed in serial sections in regions of ectopic bone. Contralateral "natural healing" tendons lacked both markers. In the other two studies, the effects of osteogenic supplements and construct geometry (monolayer vs. 3-D) on ALP activity were studied to test three hypotheses: that rabbit MSCs increase ALP activity over time in monolayer culture conditions; that adding osteogenic inducing supplements to the culture medium increases cellular protein in monolayer culture; and that rabbit MSCs increase ALP activity both in monolayer and in 3-D constructs, with and without media supplements. Culture in monolayer under similar conditions to in vivo (as in the first study) did not increase ALP at 2 or 4 weeks. Medium designed to increase osteogenic activity significantly increased cell numbers (cellular protein increased by 260%) but did not affect ALP activity either in monolayer or 3-D constructs (p>0.12). However, MSCs in 3-D constructs exhibited higher ALP activity than cells in monolayer, both in the presence (p<0.045) and absence of supplement (p<0.005). These results suggest that in vitro conditions may critically influence cell differentiation and protein expression. Mechanisms responsible for these effects are currently under investigation.
In situ transmission electron microscopy studies of silicide-mediated crystallization of amorphous silicon (1992)

The silicide-mediated phase transformation of amorphous to crystalline silicon was observed in situ in the transmission electron microscope. Crystallization of nickel-implanted amorphous silicon occurred at ∼500 °C. Nickel disilicide precipitates were observed to migrate through an amorphous Si film leaving a trail of crystalline Si. Growth occurred parallel to 〈111〉 directions. High resolution electron microscopy revealed an epitaxial NiSi2/Si(111) interface which was Type A. A diffusion-controlled mechanism for the enhanced crystallization rate was determined.
Intracellular Cysteine Residues in the Tail of MHC Class I Proteins Are Crucial for Extracellular Recognition by Leukocyte Ig-Like Receptor 1 (2007)

The activity of NK cells is regulated by activating receptors that recognize mainly stress-induced ligands and by inhibitory receptors that recognize mostly MHC class I proteins on target cells. Comparing the cytoplasmic tail sequences of various MHC class I proteins revealed the presence of unique cysteine residues in some of the MHC class I molecules which are absent in others. To study the role of these unique cysteines, we performed site specific mutagenesis, generating MHC class I molecules lacking these cysteines, and demonstrated that their expression on the cell surface was impaired. Surprisingly, we demonstrated that these cysteines are crucial for the surface binding of the leukocyte Ig-like receptor 1 inhibitory receptor to the MHC class I proteins, but not for the binding of the KIR2DL1 inhibitory receptor. In addition, we demonstrated that the cysteine residues in the cytoplasmic tail of MHC class I proteins are crucial for their egress from the endoplasmic reticulum and for their palmitoylation, thus probably affecting their expression on the cell surface. Finally, we show that the cysteine residues are important for proper extracellular conformation. Thus, although the interaction between leukocyte Ig-like receptor 1 and MHC class I proteins is formed between two extracellular surfaces, the intracellular components of MHC class I proteins play a crucial role in this recognition.
Photocrosslinkable liquid‐crystalline block copolymers with coumarin units synthesized with atom transfer radical polymerization (2003)

Abstract A new class of liquid‐crystalline (LC) homopolymers of poly{11‐[4‐(3‐ethoxycarbonyl‐coumarin‐7‐oxy)‐carbonylphenyloxy]‐undecyl methacrylate} containing a coumarin moiety as a photocrosslinkable unit with various polymerization degrees and their LC‐coil diblock and LC‐coil‐LC triblock copolymers with polystyrene as the coil segment was synthesized with the atom transfer radical polymerization method. All the homopolymers and block copolymers synthesized here exhibited narrow polydispersities, indicating well‐controlled living polymerization. Differential scanning calorimetry, polarized optical microscopy, and wide‐angle X‐ray diffraction confirmed that all the homopolymers and block copolymers exhibit a monolayer smectic A phase. Coumarin moieties in the polymers can be photodimerized under λ &gt; 300 nm light irradiation to yield crosslinked network structures, which improve the thermal stability of a polymer nanostructure because of microphase separation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2197–2206, 2003
Effect of dietary inducer dimethylfumarate on glutathione in cultured human retinal pigment epithelial cells. (1999)

These results suggest a means by which the antioxidant capability of hRPE may be augmented without direct antioxidant supplementation. Specifically, a dietary compound that conjugates with GSH can induce GSH synthesis, increase GSH concentration, and improve protection by GSH-dependent detoxification pathways in hRPE. However, the early depletion of GSH before stimulated synthesis necessitates caution in prevention strategies using dietary inducers.
Functional analysis of promoters in the nisin gene cluster of Lactococcus lactis (1996)

The promoters in the nisin gene cluster nisABTCIPRKFEG of Lactococcus lactis were characterized by primer extension and transcriptional fusions to the Escherichia coli promoterless beta-glucuronidase gene (gusA). Three promoters preceding the nisA, nisR, and nisF genes, which all give rise to gusA expression in the nisin-producing strain L. lactis NZ9700, were identified. The transcriptional autoregulation of nisA by signal transduction involving the sensor histidine kinase NisK and the response regulator NisR has been demonstrated previously (0. P. Kuipers, M. M. Beerthuyzen, P. G. G. A. de Ruyter, E. J. Luesink, and W. M. de Vos, J. Biol. Chem. 270: 27299-27304, 1995), and therefore the possible nisin-dependent expression of gusA under control of the nisR and nisF promoters was also investigated. The nisR promoter was shown to direct nisin-independent gusA expression in L. lactis MG 1363, which is a nisin-transposon- and plasmid-free strain. L. lactis NZ9800, which does not produce nisin because of a deletion in the nisA gene, containing the nisF-gusA fusion plasmid, gave rise to beta-glucuronidase production only after induction by nisin. A similar regulation was found in L. lactis NZ3900, which contains a single copy of the nisR and nisK genes but no other genes of the nisin gene cluster. In contrast, when the nisK gene was disrupted, no beta-glucuronidase activity directed by the nisF promoter could be detected even after induction with nisin. These results show that, like the nisA promoter, the nisF promoter is nisin inducible. The nisF and nisA promoter sequences have significant similarities and contain a conserved region that could be important for transcriptional control.