A Comparative Study of the Application of FACTS Devices in Wind Power Plants of the Southeast Area of the Mexican Electric System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beltran-Valle, Omar; Pena-Gallardo, Rafael; Segundo-Ramirez, Juan

This paper presents a comparative study of the application of Flexible AC Transmission System (FACTS) devices, as Thyristor Controlled Series Capacitor (TCSC), Static Synchronous Compensator (STATCOM) and Unified Power Controller (UPFC) on congestion management and voltage support in the area of the Istmo of Tehuantepec, Oaxaca, Mexico. The present work provides an analysis about the performance of the control of active and reactive power of the FACTS controllers applied to mentioned problems in the power system.

Analysis of Nuclear Factor-κB (NF-κB) Essential Modulator (NEMO) Binding to Linear and Lysine-linked Ubiquitin Chains and Its Role in the Activation of NF-κB*

PubMed Central

Kensche, Tobias; Tokunaga, Fuminori; Ikeda, Fumiyo; Goto, Eiji; Iwai, Kazuhiro; Dikic, Ivan

2012-01-01

Nuclear factor-κB (NF-κB) essential modulator (NEMO), a component of the inhibitor of κB kinase (IKK) complex, controls NF-κB signaling by binding to ubiquitin chains. Structural studies of NEMO provided a rationale for the specific binding between the UBAN (ubiquitin binding in ABIN and NEMO) domain of NEMO and linear (Met-1-linked) di-ubiquitin chains. Full-length NEMO can also interact with Lys-11-, Lys-48-, and Lys-63-linked ubiquitin chains of varying length in cells. Here, we show that purified full-length NEMO binds preferentially to linear ubiquitin chains in competition with lysine-linked ubiquitin chains of defined length, including long Lys-63-linked deca-ubiquitins. Linear di-ubiquitins were sufficient to activate both the IKK complex in vitro and to trigger maximal NF-κB activation in cells. In TNFα-stimulated cells, NEMO chimeras engineered to bind exclusively to Lys-63-linked ubiquitin chains mediated partial NF-κB activation compared with cells expressing NEMO that binds to linear ubiquitin chains. We propose that NEMO functions as a high affinity receptor for linear ubiquitin chains and a low affinity receptor for long lysine-linked ubiquitin chains. This phenomenon could explain quantitatively distinct NF-κB activation patterns in response to numerous cell stimuli. PMID:22605335

HTLV-1 Tax Induces Formation of the Active Macromolecular IKK Complex by Generating Lys63- and Met1-Linked Hybrid Polyubiquitin Chains.

PubMed

Shibata, Yuri; Tokunaga, Fuminori; Goto, Eiji; Komatsu, Ginga; Gohda, Jin; Saeki, Yasushi; Tanaka, Keiji; Takahashi, Hirotaka; Sawasaki, Tatsuya; Inoue, Satoshi; Oshiumi, Hiroyuki; Seya, Tsukasa; Nakano, Hiroyasu; Tanaka, Yuetsu; Iwai, Kazuhiro; Inoue, Jun-Ichiro

2017-01-01

The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) is crucial for the development of adult T-cell leukemia (ATL), a highly malignant CD4+ T cell neoplasm. Among the multiple aberrant Tax-induced effects on cellular processes, persistent activation of transcription factor NF-κB, which is activated only transiently upon physiological stimulation, is essential for leukemogenesis. We and others have shown that Tax induces activation of the IκB kinase (IKK) complex, which is a critical step in NF-κB activation, by generating Lys63-linked polyubiquitin chains. However, the molecular mechanism underlying Tax-induced IKK activation is controversial and not fully understood. Here, we demonstrate that Tax recruits linear (Met1-linked) ubiquitin chain assembly complex (LUBAC) to the IKK complex and that Tax fails to induce IKK activation in cells that lack LUBAC activity. Mass spectrometric analyses revealed that both Lys63-linked and Met1-linked polyubiquitin chains are associated with the IKK complex. Furthermore, treatment of the IKK-associated polyubiquitin chains with Met1-linked-chain-specific deubiquitinase (OTULIN) resulted in the reduction of high molecular weight polyubiquitin chains and the generation of short Lys63-linked ubiquitin chains, indicating that Tax can induce the generation of Lys63- and Met1-linked hybrid polyubiquitin chains. We also demonstrate that Tax induces formation of the active macromolecular IKK complex and that the blocking of Tax-induced polyubiquitin chain synthesis inhibited formation of the macromolecular complex. Taken together, these results lead us to propose a novel model in which the hybrid-chain-dependent oligomerization of the IKK complex triggered by Tax leads to trans-autophosphorylation-mediated IKK activation.

HTLV-1 Tax Induces Formation of the Active Macromolecular IKK Complex by Generating Lys63- and Met1-Linked Hybrid Polyubiquitin Chains

PubMed Central

Tokunaga, Fuminori; Goto, Eiji; Komatsu, Ginga; Saeki, Yasushi; Tanaka, Keiji; Takahashi, Hirotaka; Sawasaki, Tatsuya; Inoue, Satoshi; Oshiumi, Hiroyuki; Seya, Tsukasa; Nakano, Hiroyasu; Tanaka, Yuetsu; Iwai, Kazuhiro

2017-01-01

The Tax protein of human T-cell leukemia virus type 1 (HTLV-1) is crucial for the development of adult T-cell leukemia (ATL), a highly malignant CD4+ T cell neoplasm. Among the multiple aberrant Tax-induced effects on cellular processes, persistent activation of transcription factor NF-κB, which is activated only transiently upon physiological stimulation, is essential for leukemogenesis. We and others have shown that Tax induces activation of the IκB kinase (IKK) complex, which is a critical step in NF-κB activation, by generating Lys63-linked polyubiquitin chains. However, the molecular mechanism underlying Tax-induced IKK activation is controversial and not fully understood. Here, we demonstrate that Tax recruits linear (Met1-linked) ubiquitin chain assembly complex (LUBAC) to the IKK complex and that Tax fails to induce IKK activation in cells that lack LUBAC activity. Mass spectrometric analyses revealed that both Lys63-linked and Met1-linked polyubiquitin chains are associated with the IKK complex. Furthermore, treatment of the IKK-associated polyubiquitin chains with Met1-linked-chain-specific deubiquitinase (OTULIN) resulted in the reduction of high molecular weight polyubiquitin chains and the generation of short Lys63-linked ubiquitin chains, indicating that Tax can induce the generation of Lys63- and Met1-linked hybrid polyubiquitin chains. We also demonstrate that Tax induces formation of the active macromolecular IKK complex and that the blocking of Tax-induced polyubiquitin chain synthesis inhibited formation of the macromolecular complex. Taken together, these results lead us to propose a novel model in which the hybrid-chain-dependent oligomerization of the IKK complex triggered by Tax leads to trans-autophosphorylation-mediated IKK activation. PMID:28103322

The parallel reaction monitoring method contributes to a highly sensitive polyubiquitin chain quantification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuchiya, Hikaru; Tanaka, Keiji, E-mail: tanaka-kj@igakuken.or.jp; Saeki, Yasushi, E-mail: saeki-ys@igakuken.or.jp

2013-06-28

Highlights: •The parallel reaction monitoring method was applied to ubiquitin quantification. •The ubiquitin PRM method is highly sensitive even in biological samples. •Using the method, we revealed that Ufd4 assembles the K29-linked ubiquitin chain. -- Abstract: Ubiquitylation is an essential posttranslational protein modification that is implicated in a diverse array of cellular functions. Although cells contain eight structurally distinct types of polyubiquitin chains, detailed function of several chain types including K29-linked chains has remained largely unclear. Current mass spectrometry (MS)-based quantification methods are highly inefficient for low abundant atypical chains, such as K29- and M1-linked chains, in complex mixtures thatmore » typically contain highly abundant proteins. In this study, we applied parallel reaction monitoring (PRM), a quantitative, high-resolution MS method, to quantify ubiquitin chains. The ubiquitin PRM method allows us to quantify 100 attomole amounts of all possible ubiquitin chains in cell extracts. Furthermore, we quantified ubiquitylation levels of ubiquitin-proline-β-galactosidase (Ub-P-βgal), a historically known model substrate of the ubiquitin fusion degradation (UFD) pathway. In wild-type cells, Ub-P-βgal is modified with ubiquitin chains consisting of 21% K29- and 78% K48-linked chains. In contrast, K29-linked chains are not detected in UFD4 knockout cells, suggesting that Ufd4 assembles the K29-linked ubiquitin chain(s) on Ub-P-βgal in vivo. Thus, the ubiquitin PRM is a novel, useful, quantitative method for analyzing the highly complicated ubiquitin system.« less

Ufd2p synthesizes branched ubiquitin chains to promote the degradation of substrates modified with atypical chains

PubMed Central

Liu, Chao; Liu, Weixiao; Ye, Yihong; Li, Wei

2017-01-01

Ubiquitination of a subset of proteins by ubiquitin chain elongation factors (E4), represented by Ufd2p in Saccharomyces cerevisiae, is a pivotal regulator for many biological processes. However, the mechanism of Ufd2p-mediated ubiquitination is largely unclear. Here, we show that Ufd2p catalyses K48-linked multi-monoubiquitination on K29-linked ubiquitin chains assembled by the ubiquitin ligase (Ufd4p), resulting in branched ubiquitin chains. This reaction depends on the interaction of K29-linked ubiquitin chains with two N-terminal loops of Ufd2p. Only following the addition of K48-linked ubiquitin to substrates modified with K29-linked ubiquitin chains, can the substrates be escorted to the proteasome for degradation. We demonstrate that this ubiquitin chain linkage switching reaction is essential for ERAD, oleic acid and acid pH resistance in yeast. Thus, our results suggest that Ufd2p functions by switching ubiquitin chain linkages to allow the degradation of proteins modified with a ubiquitin linkage, which is normally not targeted to the proteasome. PMID:28165462

Real time hardware implementation of power converters for grid integration of distributed generation and STATCOM systems

NASA Astrophysics Data System (ADS)

Jaithwa, Ishan

Deployment of smart grid technologies is accelerating. Smart grid enables bidirectional flows of energy and energy-related communications. The future electricity grid will look very different from today's power system. Large variable renewable energy sources will provide a greater portion of electricity, small DERs and energy storage systems will become more common, and utilities will operate many different kinds of energy efficiency. All of these changes will add complexity to the grid and require operators to be able to respond to fast dynamic changes to maintain system stability and security. This thesis investigates advanced control technology for grid integration of renewable energy sources and STATCOM systems by verifying them on real time hardware experiments using two different systems: d SPACE and OPAL RT. Three controls: conventional, direct vector control and the intelligent Neural network control were first simulated using Matlab to check the stability and safety of the system and were then implemented on real time hardware using the d SPACE and OPAL RT systems. The thesis then shows how dynamic-programming (DP) methods employed to train the neural networks are better than any other controllers where, an optimal control strategy is developed to ensure effective power delivery and to improve system stability. Through real time hardware implementation it is proved that the neural vector control approach produces the fastest response time, low overshoot, and, the best performance compared to the conventional standard vector control method and DCC vector control technique. Finally the entrepreneurial approach taken to drive the technologies from the lab to market via ORANGE ELECTRIC is discussed in brief.

Effects of enterprise technology on supply chain collaboration: analysis of China-linked supply chain

NASA Astrophysics Data System (ADS)

Li, Ling

2012-02-01

Supply chain collaboration has received increasing attention from scholars and practitioners in recent years. However, our understanding of how enterprise information technology facilitates supply chain collaboration is still very limited, especially with regard to Chinese enterprise ownerships such as state-owned firms, joint-venture firms and local village-owned firms. This paper extends the theory established in enterprise information technology (IT) and supply chain collaboration literature and relates it with coordination in China-linked supply chain. Drawing upon an empirical study from 177 Chinese companies, we provide three major findings: (i) uncovered the importance of leveraging enterprise IT through supply chain collaboration; (ii) identified the relationship between enterprise ownership and enterprise technology use and supply chain collaboration in China-linked supply chain and (iii) illustrated effects of supply chain collaborative activities on operational and market performance.

Human disease mortality kinetics are explored through a chain model embodying principles of extreme value theory and competing risks.

PubMed

Juckett, D A; Rosenberg, B

1992-04-21

The distributions for human disease-specific mortality exhibit two striking characteristics: survivorship curves that intersect near the longevity limit; and, the clustering of best-fitting Weibull shape parameter values into groups centered on integers. Correspondingly, we have hypothesized that the distribution intersections result from either competitive processes or population partitioning and the integral clustering in the shape parameter results from the occurrence of a small number of rare, rate-limiting events in disease progression. In this report we initiate a theoretical examination of these questions by exploring serial chain model dynamics and parameteric competing risks theory. The links in our chain models are composed of more than one bond, where the number of bonds in a link are denoted the link size and are the number of events necessary to break the link and, hence, the chain. We explored chains with all links of the same size or with segments of the chain composed of different size links (competition). Simulations showed that chain breakage dynamics depended on the weakest-link principle and followed kinetics of extreme-values which were very similar to human mortality kinetics. In particular, failure distributions for simple chains were Weibull-type extreme-value distributions with shape parameter values that were identifiable with the integral link size in the limit of infinite chain length. Furthermore, for chains composed of several segments of differing link size, the survival distributions for the various segments converged at a point in the S(t) tails indistinguishable from human data. This was also predicted by parameteric competing risks theory using Weibull underlying distributions. In both the competitive chain simulations and the parametric competing risks theory, however, the shape values for the intersecting distributions deviated from the integer values typical of human data. We conclude that rare events can be the source of integral shapes in human mortality, that convergence is a salient feature of multiple endpoints, but that pure competition may not be the best explanation for the exact type of convergence observable in human mortality. Finally, while the chain models were not motivated by any specific biological structures, interesting biological correlates to them may be useful in gerontological research.

Tandem UIMs confer Lys48 ubiquitin chain substrate preference to deubiquitinase USP25

PubMed Central

Kawaguchi, Kohei; Uo, Kazune; Tanaka, Toshiaki; Komada, Masayuki

2017-01-01

Ubiquitin-specific protease (USP) 25, belonging to the USP family of deubiquitinases, harbors two tandem ubiquitin-interacting motifs (UIMs), a ~20-amino-acid α-helical stretch that binds to ubiquitin. However, the role of the UIMs in USP25 remains unclear. Here we show that the tandem UIM region binds to Lys48-, but not Lys63-, linked ubiquitin chains, where the two UIMs played a critical and cooperative role. Purified USP25 exhibited higher ubiquitin isopeptidase activity to Lys48-, than to Lys63-, linked ubiquitin chains. Mutations that disrupted the ubiquitin-binding ability of the tandem UIMs resulted in a reduced ubiquitin isopeptidase activity of USP25, suggesting a role for the UIMs in exerting the full catalytic activity of USP25. Moreover, when mutations that convert the binding preference from Lys48- to Lys63-linked ubiquitin chains were introduced into the tandem UIM region, the USP25 mutants acquired elevated and reduced isopeptidase activity toward Lys63- and Lys48-linked ubiquitin chains, respectively. These results suggested that the binding preference of the tandem UIMs toward Lys48-linked ubiquitin chains contributes not only to the full catalytic activity but also to the ubiquitin chain substrate preference of USP25, possibly by selectively holding the Lys48-linked ubiquitin chain substrates in the proximity of the catalytic core. PMID:28327663

Modelling and control of a microgrid including photovoltaic and wind generation

NASA Astrophysics Data System (ADS)

Hussain, Mohammed Touseef

Extensive increase of distributed generation (DG) penetration and the existence of multiple DG units at distribution level have introduced the notion of micro-grid. This thesis develops a detailed non-linear and small-signal dynamic model of a microgrid that includes PV, wind and conventional small scale generation along with their power electronics interfaces and the filters. The models developed evaluate the amount of generation mix from various DGs for satisfactory steady state operation of the microgrid. In order to understand the interaction of the DGs on microgrid system initially two simpler configurations were considered. The first one consists of microalternator, PV and their electronics, and the second system consists of microalternator and wind system each connected to the power system grid. Nonlinear and linear state space model of each microgrid are developed. Small signal analysis showed that the large participation of PV/wind can drive the microgrid to the brink of unstable region without adequate control. Non-linear simulations are carried out to verify the results obtained through small-signal analysis. The role of the extent of generation mix of a composite microgrid consisting of wind, PV and conventional generation was investigated next. The findings of the smaller systems were verified through nonlinear and small signal modeling. A central supervisory capacitor energy storage controller interfaced through a STATCOM was proposed to monitor and enhance the microgrid operation. The potential of various control inputs to provide additional damping to the system has been evaluated through decomposition techniques. The signals identified to have damping contents were employed to design the supervisory control system. The controller gains were tuned through an optimal pole placement technique. Simulation studies demonstrate that the STATCOM voltage phase angle and PV inverter phase angle were the best inputs for enhanced stability boundaries.

O-linked oligosaccharides on insulin receptor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Collier, E.; Gorden, P.

1991-02-01

The insulin receptor, an integral membrane glycoprotein, is synthesized as a single-chain precursor that is cleaved to produce two mature subunits, both of which contain N-linked oligosaccharide chains and covalently linked fatty acids. We report that the beta-subunit also contains O-linked oligosaccharides. The proreceptor, alpha-subunit, and beta-subunit were labeled with (3H)mannose and (3H)galactose in the presence or absence of an inhibitor of O-linked glycosylation. Tryptic peptides from each component were separated by reverse-phase high-performance liquid chromatography. N- and O-linked oligosaccharide chains were identified on these peptides by specific enzymatic digestions. The proreceptor and alpha-subunit contained only N-linked oligosaccharides, whereas themore » beta-subunit contained both N- and O-linked oligosaccharides. The O-linked oligosaccharide chains were attached to a single tryptic fraction of the beta-subunit, which also contained N-linked chains. This fraction was further localized to the NH2-terminal tryptic peptide of the beta-subunit by specific immunoprecipitation with an anti-peptide antibody with specificity for this region. Binding of insulin and autophosphorylation of the beta-subunit were not dependent on O-linked glycosylation, because cells grown in the presence of the inhibitor exhibited a normal dose response to insulin. Therefore, the insulin receptor contains O-linked oligosaccharides on the NH2-terminal tryptic peptide of the beta-subunit, and these O-linked oligosaccharides are not necessary to the binding or autophosphorylation function of the receptor.« less

Constructing and decoding unconventional ubiquitin chains.

PubMed

Behrends, Christian; Harper, J Wade

2011-05-01

One of the most notable discoveries in the ubiquitin system during the past decade is the extensive use of diverse chain linkages to control signaling networks. Although the utility of Lys48- and Lys63-linked chains in protein turnover and molecular assembly, respectively, are well known, we are only beginning to understand how unconventional chain linkages are formed on target proteins and how such linkages are decoded by specific binding proteins. In this review, we summarize recent efforts to elucidate the machinery and mechanisms controlling assembly of Lys11-linked and linear (or Met1-linked) ubiquitin chains, and describe current models for how these chain types function in immune signaling and cell-cycle control.

Crystal Structures of Lys-63-linked tri- and di-ubiquitin Reveal a Highly Extended Chain Architecture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weeks, S.; Grasty, K; Hernandez-Cuebas, L

2009-01-01

The covalent attachment of different types of poly-ubiquitin chains signal different outcomes for the proteins so targeted. For example, a protein modified with Lys-48-linked poly-ubiquitin chains is targeted for proteasomal degradation, whereas Lys-63-linked chains encode nondegradative signals. The structural features that enable these different types of chains to encode different signals have not yet been fully elucidated. We report here the X-ray crystal structures of Lys-63-linked tri- and di-ubiquitin at resolutions of 2.3 and 1.9 {angstrom}, respectively. The tri- and di-ubiquitin species adopt essentially identical structures. In both instances, the ubiquitin chain assumes a highly extended conformation with a left-handedmore » helical twist; the helical chain contains four ubiquitin monomers per turn and has a repeat length of {approx}110 {angstrom}. Interestingly, Lys-48 ubiquitin chains also adopt a left-handed helical structure with a similar repeat length. However, the Lys-63 architecture is much more open than that of Lys-48 chains and exposes much more of the ubiquitin surface for potential recognition events. These new crystal structures are consistent with the results of solution studies of Lys-63 chain conformation, and reveal the structural basis for differential recognition of Lys-63 versus Lys-48 chains.« less

Continuous chain bit with downhole cycling capability

DOEpatents

Ritter, Don F.; St. Clair, Jack A.; Togami, Henry K.

1983-01-01

A continuous chain bit for hard rock drilling is capable of downhole cycling. A drill head assembly moves axially relative to a support body while the chain on the head assembly is held in position so that the bodily movement of the chain cycles the chain to present new composite links for drilling. A pair of spring fingers on opposite sides of the chain hold the chain against movement. The chain is held in tension by a spring-biased tensioning bar. A head at the working end of the chain supports the working links. The chain is centered by a reversing pawl and piston actuated by the pressure of the drilling mud. Detent pins lock the head assembly with respect to the support body and are also operated by the drilling mud pressure. A restricted nozzle with a divergent outlet sprays drilling mud into the cavity to remove debris. Indication of the centered position of the chain is provided by noting a low pressure reading indicating proper alignment of drilling mud slots on the links with the corresponding feed branches.

Assembly and Function of Heterotypic Ubiquitin Chains in Cell-Cycle and Protein Quality Control.

PubMed

Yau, Richard G; Doerner, Kerstin; Castellanos, Erick R; Haakonsen, Diane L; Werner, Achim; Wang, Nan; Yang, X William; Martinez-Martin, Nadia; Matsumoto, Marissa L; Dixit, Vishva M; Rape, Michael

2017-11-02

Posttranslational modification with ubiquitin chains controls cell fate in all eukaryotes. Depending on the connectivity between subunits, different ubiquitin chain types trigger distinct outputs, as seen with K48- and K63-linked conjugates that drive protein degradation or complex assembly, respectively. Recent biochemical analyses also suggested roles for mixed or branched ubiquitin chains, yet without a method to monitor endogenous conjugates, the physiological significance of heterotypic polymers remained poorly understood. Here, we engineered a bispecific antibody to detect K11/K48-linked chains and identified mitotic regulators, misfolded nascent polypeptides, and pathological Huntingtin variants as their endogenous substrates. We show that K11/K48-linked chains are synthesized and processed by essential ubiquitin ligases and effectors that are mutated across neurodegenerative diseases; accordingly, these conjugates promote rapid proteasomal clearance of aggregation-prone proteins. By revealing key roles of K11/K48-linked chains in cell-cycle and quality control, we establish heterotypic ubiquitin conjugates as important carriers of biological information. Copyright © 2017 Elsevier Inc. All rights reserved.

The chain of cross-contamination: link-by-link.

PubMed

Schwartz, Jeanne

2002-01-01

Conscious efforts must be made to break the chain of cross-contamination--link-by-link. Pay attention to detail Avoid being careless Avoid touching objects while wearing soiled gloves Frequently wash hands (15-second hand washing) to remove pathogens--before and after gloving, and before handling food or drink Wear all PPE, and change accordingly.

Signaled and Unsignaled Terminal Links in Concurrent Chains I: Effects of Reinforcer Probability and Immediacy

ERIC Educational Resources Information Center

Mattson, Karla M.; Hucks, Andrew; Grace, Randolph C.; McLean, Anthony P.

2010-01-01

Eight pigeons responded in a three-component concurrent-chains procedure, with either independent or dependent initial links. Relative probability and immediacy of reinforcement in the terminal links were both varied, and outcomes on individual trials (reinforcement or nonreinforcement) were either signaled or unsignaled. Terminal-link fixed-time…

47 CFR 73.3555 - Multiple ownership.

Code of Federal Regulations, 2010 CFR

2010-10-01

... vertical ownership chain and application of the relevant attribution benchmark to the resulting product, except that wherever the ownership percentage for any link in the chain exceeds 50%, it shall not be... multiplication of the ownership percentages for each link in the vertical ownership chain and application of the...

47 CFR 73.3555 - Multiple ownership.

Code of Federal Regulations, 2011 CFR

2011-10-01

... vertical ownership chain and application of the relevant attribution benchmark to the resulting product, except that wherever the ownership percentage for any link in the chain exceeds 50%, it shall not be... multiplication of the ownership percentages for each link in the vertical ownership chain and application of the...

47 CFR 73.3555 - Multiple ownership.

Code of Federal Regulations, 2014 CFR

2014-10-01

... vertical ownership chain and application of the relevant attribution benchmark to the resulting product, except that wherever the ownership percentage for any link in the chain exceeds 50%, it shall not be... multiplication of the ownership percentages for each link in the vertical ownership chain and application of the...

47 CFR 73.3555 - Multiple ownership.

Code of Federal Regulations, 2012 CFR

2012-10-01

... vertical ownership chain and application of the relevant attribution benchmark to the resulting product, except that wherever the ownership percentage for any link in the chain exceeds 50%, it shall not be... multiplication of the ownership percentages for each link in the vertical ownership chain and application of the...

47 CFR 73.3555 - Multiple ownership.

Code of Federal Regulations, 2013 CFR

2013-10-01

... vertical ownership chain and application of the relevant attribution benchmark to the resulting product, except that wherever the ownership percentage for any link in the chain exceeds 50%, it shall not be... multiplication of the ownership percentages for each link in the vertical ownership chain and application of the...

Twist-writhe partitioning in a coarse-grained DNA minicircle model

NASA Astrophysics Data System (ADS)

Sayar, Mehmet; Avşaroǧlu, Barış; Kabakçıoǧlu, Alkan

2010-04-01

Here we present a systematic study of supercoil formation in DNA minicircles under varying linking number by using molecular-dynamics simulations of a two-bead coarse-grained model. Our model is designed with the purpose of simulating long chains without sacrificing the characteristic structural properties of the DNA molecule, such as its helicity, backbone directionality, and the presence of major and minor grooves. The model parameters are extracted directly from full-atomistic simulations of DNA oligomers via Boltzmann inversion; therefore, our results can be interpreted as an extrapolation of those simulations to presently inaccessible chain lengths and simulation times. Using this model, we measure the twist/writhe partitioning in DNA minicircles, in particular its dependence on the chain length and excess linking number. We observe an asymmetric supercoiling transition consistent with experiments. Our results suggest that the fraction of the linking number absorbed as twist and writhe is nontrivially dependent on chain length and excess linking number. Beyond the supercoiling transition, chains of the order of one persistence length carry equal amounts of twist and writhe. For longer chains, an increasing fraction of the linking number is absorbed by the writhe.

Shifting stroke care from the hospital to the nursing home: explaining the outcomes of a Dutch case.

PubMed

van Raak, Arno; Groothuis, Siebren; van der Aa, Robert; Limburg, Martien; Vos, Leti

2010-12-01

Supply chains can contribute to better care for stroke patients and more efficiency. However, such outcomes are hampered when links in the chain are weak. The article aims to further the knowledge about the causes and possible improvements of weak links thereby using theory about rules for action and routines (action patterns). We executed a single case study of a chain of service delivery to stroke patients by a university hospital and a nursing home in the city of Maastricht, the Netherlands. Methods included document study, interviews, observations, process mapping, use of data matrices and performance of t-tests. In the case, the care delivery process in the chain was redesigned to improve the flow of patients and to reduce the length of hospital stay. Length of stay was reduced. However, transfer of patients from the hospital to the nursing home was hampered. At this weak link in the chain, the redesign clashed with the routines of hospital paramedics who did not want to work according to the redesign. The applied theory is useful to understand why a link in a supply chain is weak. Negotiations can be used to strengthen a link. © 2010 Blackwell Publishing Ltd.

Structural analysis of N-linked carbohydrate chains of funnel web spider (Agelenopsis aperta) venom peptide isomerase.

PubMed

Shikata, Y; Ohe, H; Mano, N; Kuwada, M; Asakawa, N

1998-06-01

The structure of the N-linked carbohydrate chains of peptide isomerase from the venom of the funnel web spider (Agelenopsis aperta) has been analyzed. Carbohydrates were released from peptide isomerase by hydrazinolysis and reductively aminated with 2-aminopyridine. The fluorescent derivatives were purified by phenol/chloroform extraction, followed by size-exclusion HPLC. The structure of the purified pyridylamino (PA-) carbohydrate chains were analyzed by a combination of two-dimensional HPLC mapping, sugar composition analysis, sequential exoglycosidase digestions, and mass spectrometry. The peptide isomerase contains six kinds of N-linked carbohydrate chains of truncated high-mannose type, with a fucose alpha 1-6 linked to the reducing N-acetylglucosamine in approximately 80% of them.

Employer-Led Organizations and Skill Supply Chains: Linking Worker Advancement with the Skill Needs of Employers. Issue Brief.

ERIC Educational Resources Information Center

Mills, Jack; Prince, Heath

Skill supply chains apply a chain strategy to human resources to make the labor market more efficient. They link the multiple skill levels in a given labor market within a network of recruitment pathways for employers and advancement pathways for workers. Skill supply chains are based on employers' actual skill needs and on the principle that…

Some Effects of Procedural Variations on Choice Responding in Concurrent Chains

ERIC Educational Resources Information Center

Moore, J.

2009-01-01

The present research used pigeons in a three-key operant chamber and varied procedural features pertaining to both initial and terminal links of concurrent chains. The initial links randomly alternated on the side keys during a session, while the terminal links always appeared on the center key. Both equal and unequal initial-link schedules were…

Independence of Terminal-Link Entry Rate and Immediacy in Concurrent Chains

ERIC Educational Resources Information Center

Berg, Mark E.; Grace, Randolph C.

2004-01-01

In Phase 1, 4 pigeons were trained on a three-component multiple concurrent-chains procedure in which components differed only in terms of relative terminal-link entry rate. The terminal links were variable-interval schedules and were varied across four conditions to produce immediacy ratios of 4:1, 1:4, 2:1, and 1:2. Relative terminal-link entry…

A Consideration of Stable Operating Power Limits of HVDC System Composed of Voltage Source Converters

NASA Astrophysics Data System (ADS)

Konishi, Hiroo; Takahashi, Choei; Kishibe, Hideto; Sato, Hiromichi

The stable operating power limits of a small scale HVDC system composed of voltage source converters (VSC-HVDC system) are analyzed with a simple model. The VSC-HVDC system could operate where the AC system must be somewhat larger in capacity than the VSC-HVDC system capacity. The stable operating power limits were between one and two times the SCR (short circuit ratio). When the inverter of the VSC-HVDC system was operated with lead reactive (capacitive) power control conditions, the stable operating limits were increased through AC voltage stabilization. When the inverter was a STATCOM operation, it could operate regardless of the SCR but regions within allowable AC voltage variations.

Rainflow Algorithm-Based Lifetime Estimation of Power Semiconductors in Utility Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

GopiReddy, Lakshmi Reddy; Tolbert, Leon M.; Ozpineci, Burak

Rainflow algorithms are one of the popular counting methods used in fatigue and failure analysis in conjunction with semiconductor lifetime estimation models. However, the rain-flow algorithm used in power semiconductor reliability does not consider the time-dependent mean temperature calculation. The equivalent temperature calculation proposed by Nagode et al. is applied to semiconductor lifetime estimation in this paper. A month-long arc furnace load profile is used as a test profile to estimate temperatures in insulated-gate bipolar transistors (IGBTs) in a STATCOM for reactive compensation of load. In conclusion, the degradation in the life of the IGBT power device is predicted basedmore » on time-dependent temperature calculation.« less

Rainflow Algorithm-Based Lifetime Estimation of Power Semiconductors in Utility Applications

DOE PAGES

GopiReddy, Lakshmi Reddy; Tolbert, Leon M.; Ozpineci, Burak; ...

2015-07-15

Rainflow algorithms are one of the popular counting methods used in fatigue and failure analysis in conjunction with semiconductor lifetime estimation models. However, the rain-flow algorithm used in power semiconductor reliability does not consider the time-dependent mean temperature calculation. The equivalent temperature calculation proposed by Nagode et al. is applied to semiconductor lifetime estimation in this paper. A month-long arc furnace load profile is used as a test profile to estimate temperatures in insulated-gate bipolar transistors (IGBTs) in a STATCOM for reactive compensation of load. In conclusion, the degradation in the life of the IGBT power device is predicted basedmore » on time-dependent temperature calculation.« less

Kinetic chain contributions to elbow function and dysfunction in sports.

PubMed

Ben Kibler, W; Sciascia, Aaron

2004-10-01

The elbow functions in throwing and other athletic activities as a link in the kinetic chain of force development, regulation, and transfer. Efficient function, with maximal performance and minimal injury risk, requires optimum activation of all the link in the kinetic chain. Injury is often associated with alterations in force production or regulation capabilities in links that may be distant to the site of injury. Evaluation of injured athletes should include screening examinations for these areas, and treatment and conditioning should also include these areas.

The N-Linked Outer Chain Mannans and the Dfg5p and Dcw1p Endo-α-1,6-Mannanases Are Needed for Incorporation of Candida albicans Glycoproteins into the Cell Wall

PubMed Central

Ao, Jie; Chinnici, Jennifer L.; Maddi, Abhiram

2015-01-01

A biochemical pathway for the incorporation of cell wall protein into the cell wall of Neurospora crassa was recently proposed. In this pathway, the DFG-5 and DCW-1 endo-α-1,6-mannanases function to covalently cross-link cell wall protein-associated N-linked galactomannans, which are structurally related to the yeast outer chain mannans, into the cell wall glucan-chitin matrix. In this report, we demonstrate that the mannosyltransferase enzyme Och1p, which is needed for the synthesis of the N-linked outer chain mannan, is essential for the incorporation of cell wall glycoproteins into the Candida albicans cell wall. Using endoglycosidases, we show that C. albicans cell wall proteins are cross-linked into the cell wall via their N-linked outer chain mannans. We further demonstrate that the Dfg5p and Dcw1p α-1,6-mannanases are needed for the incorporation of cell wall glycoproteins into the C. albicans cell wall. Our results support the hypothesis that the Dfg5p and Dcw1p α-1,6-mannanases incorporate cell wall glycoproteins into the C. albicans cell wall by cross-linking outer chain mannans into the cell wall glucan-chitin matrix. PMID:26048011

Central catalytic domain of BRAP (RNF52) recognizes the types of ubiquitin chains and utilizes oligo-ubiquitin for ubiquitylation

PubMed Central

Hanada, Kazuharu; Ohsawa, Noboru

2017-01-01

Really interesting new gene (RING)-finger protein 52 (RNF52), an E3 ubiquitin ligase, is found in eukaryotes from yeast to humans. Human RNF52 is known as breast cancer type 1 susceptibility protein (BRCA1)-associated protein 2 (BRAP or BRAP2). The central catalytic domain of BRAP comprises four subdomains: nucleotide-binding α/β plait (NBP), really interesting new gene (RING) zinc finger, ubiquitin-specific protease (UBP)-like zinc finger (ZfUBP), and coiled-coil (CC). This domain architecture is conserved in RNF52 orthologs; however, the domain's function in the ubiquitin system has not been delineated. In the present study, we discovered that the RNF52 domain, comprising NBP–RING–ZfUBP–CC, binds to ubiquitin chains (oligo-ubiquitin) but not to the ubiquitin monomers, and can utilize various ubiquitin chains for ubiquitylation and auto-ubiquitylation. The RNF52 domain preferentially bound to M1- and K63-linked di-ubiquitin chains, weakly to K27-linked chains, but not to K6-, K11-, or K48-linked chains. The binding preferences of the RNF52 domain for ubiquitin-linkage types corresponded to ubiquitin usage in the ubiquitylation reaction, except for K11-, K29-, and K33-linked chains. Additionally, the RNF52 domain directly ligated the intact M1-linked, tri-, and tetra-ubiquitin chains and recognized the structural alterations caused by the phosphomimetic mutation of these ubiquitin chains. Full-length BRAP had nearly the same specificity for the ubiquitin-chain types as the RNF52 domain alone. Mass spectrometry analysis of oligomeric ubiquitylation products, mediated by the RNF52 domain, revealed that the ubiquitin-linkage types and auto-ubiquitylation sites depend on the length of ubiquitin chains. Here, we propose a model for the oligomeric ubiquitylation process, controlled by the RNF52 domain, which is not a sequential assembly process involving monomers. PMID:28768733

Compartmentalization Technologies via Self-Assembly and Cross-Linking of Amphiphilic Random Block Copolymers in Water.

PubMed

Matsumoto, Mayuko; Terashima, Takaya; Matsumoto, Kazuma; Takenaka, Mikihito; Sawamoto, Mitsuo

2017-05-31

Orthogonal self-assembly and intramolecular cross-linking of amphiphilic random block copolymers in water afforded an approach to tailor-make well-defined compartments and domains in single polymer chains and nanoaggregates. For a double compartment single-chain polymer, an amphiphilic random block copolymer bearing hydrophilic poly(ethylene glycol) (PEG) and hydrophobic dodecyl, benzyl, and olefin pendants was synthesized by living radical polymerization (LRP) and postfunctionalization; the dodecyl and benzyl units were incorporated into the different block segments, whereas PEG pendants were statistically attached along a chain. The copolymer self-folded via the orthogonal self-assembly of hydrophobic dodecyl and benzyl pendants in water, followed by intramolecular cross-linking, to form a single-chain polymer carrying double yet distinct hydrophobic nanocompartments. A single-chain cross-linked polymer with a chlorine terminal served as a globular macroinitiator for LRP to provide an amphiphilic tadpole macromolecule comprising a hydrophilic nanoparticle and a hydrophobic polymer tail; the tadpole thus self-assembled into multicompartment aggregates in water.

Choice between Single and Multiple Reinforcers in Concurrent-Chains Schedules

ERIC Educational Resources Information Center

Mazur, James E.

2006-01-01

Pigeons responded on concurrent-chains schedules with equal variable-interval schedules as initial links. One terminal link delivered a single reinforcer after a fixed delay, and the other terminal link delivered either three or five reinforcers, each preceded by a fixed delay. Some conditions included a postreinforcer delay after the single…

Temporal Context in Concurrent Chains: I. Terminal-Link Duration

ERIC Educational Resources Information Center

Grace, Randolph C.

2004-01-01

Two experiments are reported in which the ratio of the average times spent in the terminal and initial links ("Tt/Ti") in concurrent chains was varied. In Experiment 1, pigeons responded in a three-component procedure in which terminal-link variable-interval schedules were in constant ratio, but their average duration increased across components…

A Novel Algorithm for the Generation of Distinct Kinematic Chain

NASA Astrophysics Data System (ADS)

Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

2016-07-01

Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

A Novel Algorithm for the Generation of Distinct Kinematic Chain

NASA Astrophysics Data System (ADS)

Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

2018-06-01

Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

[Healthcare value chain: a model for the Brazilian healthcare system].

PubMed

Pedroso, Marcelo Caldeira; Malik, Ana Maria

2012-10-01

This article presents a model of the healthcare value chain which consists of a schematic representation of the Brazilian healthcare system. The proposed model is adapted for the Brazilian reality and has the scope and flexibility for use in academic activities and analysis of the healthcare sector in Brazil. It places emphasis on three components: the main activities of the value chain, grouped in vertical and horizontal links; the mission of each link and the main value chain flows. The proposed model consists of six vertical and three horizontal links, amounting to nine. These are: knowledge development; supply of products and technologies; healthcare services; financial intermediation; healthcare financing; healthcare consumption; regulation; distribution of healthcare products; and complementary and support services. Four flows can be used to analyze the value chain: knowledge and innovation; products and services; financial; and information.

Value of Conditioned Reinforcers as a Function of Temporal Context

ERIC Educational Resources Information Center

O'Daly, Matthew; Meyer, Steven; Fantino, Edmund

2005-01-01

In two experiments, pigeons were trained on a multiple-chain schedule, in which the initial link for one chain was a variable-interval (VI) 100s schedule and for the other chain a VI 10s schedule. The terminal links were both fixed-time 30s schedules signaled by differently colored stimuli. Following training, the pigeons had their preference for…

The Falling Chain of Hopkins, Tait, Steele and Cayley

ERIC Educational Resources Information Center

Wong, Chun Wa; Youn, Seo Ho; Yasui, Kosuke

2007-01-01

A uniform, flexible and frictionless chain falling link by link from a heap by the edge of a table falls with an acceleration g/3 if the motion is nonconservative, but g/2 if the motion is conservative, g being the acceleration due to gravity. Unable to construct such a falling chain, we use instead higher-dimensional versions of it. A home…

Role of special cross-links in structure formation of bacterial DNA polymer

NASA Astrophysics Data System (ADS)

Agarwal, Tejal; Manjunath, G. P.; Habib, Farhat; Lakshmi Vaddavalli, Pavana; Chatterji, Apratim

2018-01-01

Using data from contact maps of the DNA-polymer of Escherichia coli (E. Coli) (at kilobase pair resolution) as an input to our model, we introduce cross-links between monomers in a bead-spring model of a ring polymer at very specific points along the chain. Via suitable Monte Carlo simulations, we show that the presence of these cross-links leads to a particular organization of the chain at large (micron) length scales of the DNA. We also investigate the structure of a ring polymer with an equal number of cross-links at random positions along the chain. We find that though the polymer does get organized at the large length scales, the nature of the organization is quite different from the organization observed with cross-links at specific biologically determined positions. We used the contact map of E. Coli bacteria which has around 4.6 million base pairs in a single circular chromosome. In our coarse-grained flexible ring polymer model, we used 4642 monomer beads and observed that around 80 cross-links are enough to induce the large-scale organization of the molecule accounting for statistical fluctuations caused by thermal energy. The length of a DNA chain even of a simple bacterial cell such as E. Coli is much longer than typical proteins, hence we avoided methods used to tackle protein folding problems. We define new suitable quantities to identify the large scale structure of a polymer chain with a few cross-links.

Profiling of ornithine lipids in bacterial extracts of Rhodobacter sphaeroides by reversed-phase liquid chromatography with electrospray ionization and multistage mass spectrometry (RPLC-ESI-MS(n)).

PubMed

Granafei, Sara; Losito, Ilario; Trotta, Massimo; Italiano, Francesca; de Leo, Vincenzo; Agostiano, Angela; Palmisano, Francesco; Cataldi, Tommaso R I

2016-01-15

Ornithine lipids (OLs), a sub-group of the large (and of emerging interest) family of lipoamino acids of bacterial origin, contain a 3-hydroxy fatty acyl chain linked via an amide bond to the α-amino group of ornithine and via an ester bond to a second fatty acyl chain. OLs in extracts of Rhodobacter sphaeroides (R. sphaeroides) were investigated by high-performance reversed phase liquid chromatography (RPLC) with electrospray ionization mass spectrometry (ESI-MS) in negative ion mode using a linear ion trap (LIT). The presence of OLs bearing both saturated (i.e, 16:0, 17:0, 18:0, 19:0 and 20:0) and unsaturated chains (i.e., 18:1, 19:1, 19:2 and 20:1) was ascertained and their identification, even for isomeric, low abundance and partially co-eluting species, was achieved by low-energy collision induced dissociation (CID) multistage mass spectrometry (MS(n), n = 2-4). OLs signatures found in two R. sphaeroides strains, i.e., wild type 2.4.1 and mutant R26, were examined and up to 16 and 17 different OL species were successfully identified, respectively. OLs in both bacterial strains were characterized by several combinations of fatty chains on ester-linked and amide-linked 3-OH fatty acids. Multistage MS spectra of monoenoic amide-linked 3-OH acyl chains, allowed the identification of positional isomer of OL containing 18:1 (i.e. 9-octadecenoic) and 20:1 (i.e. 11-eicosenoic) fatty acids. The most abundant OL ([M-H](-) at m/z 717.5) in R. sphaeroides R26 was identified as OL 3-OH 20:1/19:1 (i.e., 3-OH-eicosenoic acid amide-linked to ornithine and esterified to a nonadecenoic chain containing a cyclopropane ring). An unusual OL (m/z 689.5 for the [M-H](-) ion), most likely containing a cyclopropene ester-linked acyl chain (i.e., OL 3-OH 18:0/19:2), was retrieved only in the carotenoidless mutant strain R26. Based on the biosynthetic pathways already known for cyclopropa(e)ne ring-including acyl chains, a plausible explanation was invoked for the enzymatic generation of this ester-linked chain in R. sphaeroides. Copyright © 2015 Elsevier B.V. All rights reserved.

[Suffering pain in segment lumbar spine and occurrence of weak links of biokinematics chain in kayakers and rowers].

PubMed

Wójcik, Małgorzata; Siatkowski, Idzi

2011-01-01

Spine pain is a serious clinical problem of physically active people and sportplayers . The pain may have different nature, related to different segments of the spine. Its intensity and frequency may impair the functionality of man. Most back pain is connected with the lumbo-sacral and cervical part of a spine. MAIN AIM: The hypothesis was: 1) That there were not any weak links of biokinematics chain. 2) Pain feeling in young players in the lumbar spine (LBP). The aim of this study was to determine in which direction and location the most weak links would occur in biokinematics chain and whether it was correlated with gender. In addition, it was examined whether a correlation between the weak links' presence in the lumbar spine and the occurrence of LBP existed and if it was connected with gender of the player. This study involved 40 players from Walcz School Sports Championships, including the twenty kayakers (8 women and 12 men), 13 canoeists and 7 rowers. The average age of players was 16.00 +/- 0.99, mean of training years was 4.92 +/- 2.20. Low threshold Performance Matrix tests were used for assessing the presence of weak links. Through analysis and identification of performed movement the weakest links in the biokinetics chain were found. Numeric scale was used for the evaluation of lumbar pain (LBP). The results were statistically analyzed. The main characteristics of statistical and graphical presentations were performed for the received values of weak links. The hypothesis of variances equality was verified, and all the hypotheses mentioned above were also verified using ANOVA analysis of variations and Tukey test for low threshold of weak links. 1) The presence of weak links of biokinematics chain was found in all players especially in the lumbar spine, the presence is not associated with gender. Most weak links in the lumbar part occurred in the direction of rotation. 2) There is a correlation of the weak links of the lumbar spine and LBP, but it is not connected with gender. 3) The relationship between pain suffering in the lumbar spine (LBP) and the number of weak links of biokinematics chain was defined.

Bottlebrush-Guided Polymer Crystallization Resulting in Supersoft and Reversibly Moldable Physical Networks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, William F. M.; Xie, Guojun; Vatankhah Varnoosfaderani, Mohammad

The goal of this study is to use ABA triblock copolymers with central bottlebrush B segments and crystalline linear chain A segments to demonstrate the effect of side chains on the formation and mechanical properties of physical networks cross-linked by crystallites. For this purpose, a series of bottlebrush copolymers was synthesized consisting of central amorphous bottlebrush polymer segments with a varying degree of polymerization (DP) of poly(n-butyl acrylate) (PnBA) side chains and linear tail blocks of crystallizable poly(octadecyl acrylate-stat-docosyl acrylate) (poly(ODA-stat-DA)). The materials were generated by sequential atom transfer radical polymerization (ATRP) steps starting with a series of bifunctional macroinitiatorsmore » followed by the growth of two ODA-stat-DA linear-chain tails and eventually growing poly(nBA) side chains with increasing DPs. Crystallization of the poly(ODA-stat-DA) tails resulted in a series of reversible physical networks with bottlebrush strands bridging crystalline cross-links. They displayed very low moduli of elasticity of the order of 10 3–10 4 Pa. These distinct properties are due to the bottlebrush architecture, wherein densely grafted side chains play a dual role by facilitating disentanglement of the network strands and confining crystallization of the linear-chain tails. This combination leads to physical cross-linking of supersoft networks without percolation of the crystalline phase. The cross-link density was effectively controlled by the DP of the side chains with respect to the DP of the linear tails (n A). Furthermore, shorter side chains allowed for crystallization of the linear tails of neighboring bottlebrushes, while steric repulsion between longer side chains hindered the phase separation and crystallization process and prevented network formation.« less

Bottlebrush-Guided Polymer Crystallization Resulting in Supersoft and Reversibly Moldable Physical Networks

DOE PAGES

Daniel, William F. M.; Xie, Guojun; Vatankhah Varnoosfaderani, Mohammad; ...

2017-02-24

The goal of this study is to use ABA triblock copolymers with central bottlebrush B segments and crystalline linear chain A segments to demonstrate the effect of side chains on the formation and mechanical properties of physical networks cross-linked by crystallites. For this purpose, a series of bottlebrush copolymers was synthesized consisting of central amorphous bottlebrush polymer segments with a varying degree of polymerization (DP) of poly(n-butyl acrylate) (PnBA) side chains and linear tail blocks of crystallizable poly(octadecyl acrylate-stat-docosyl acrylate) (poly(ODA-stat-DA)). The materials were generated by sequential atom transfer radical polymerization (ATRP) steps starting with a series of bifunctional macroinitiatorsmore » followed by the growth of two ODA-stat-DA linear-chain tails and eventually growing poly(nBA) side chains with increasing DPs. Crystallization of the poly(ODA-stat-DA) tails resulted in a series of reversible physical networks with bottlebrush strands bridging crystalline cross-links. They displayed very low moduli of elasticity of the order of 10 3–10 4 Pa. These distinct properties are due to the bottlebrush architecture, wherein densely grafted side chains play a dual role by facilitating disentanglement of the network strands and confining crystallization of the linear-chain tails. This combination leads to physical cross-linking of supersoft networks without percolation of the crystalline phase. The cross-link density was effectively controlled by the DP of the side chains with respect to the DP of the linear tails (n A). Furthermore, shorter side chains allowed for crystallization of the linear tails of neighboring bottlebrushes, while steric repulsion between longer side chains hindered the phase separation and crystallization process and prevented network formation.« less

26 CFR 1.472-8 - Dollar-value method of pricing LIFO inventories.

Code of Federal Regulations, 2014 CFR

2014-04-01

... “link-chain” method will be approved for taxable years beginning after December 31, 1960, only in those... nature of the pool. A taxpayer using either an index or link-chain method shall attach to his income tax return for the first taxable year beginning after December 31, 1960, for which the index or link-chain...

26 CFR 1.472-8 - Dollar-value method of pricing LIFO inventories.

Code of Federal Regulations, 2013 CFR

2013-04-01

... “link-chain” method will be approved for taxable years beginning after December 31, 1960, only in those... nature of the pool. A taxpayer using either an index or link-chain method shall attach to his income tax return for the first taxable year beginning after December 31, 1960, for which the index or link-chain...

26 CFR 1.472-8 - Dollar-value method of pricing LIFO inventories.

Code of Federal Regulations, 2011 CFR

2011-04-01

... “link-chain” method will be approved for taxable years beginning after December 31, 1960, only in those... nature of the pool. A taxpayer using either an index or link-chain method shall attach to his income tax return for the first taxable year beginning after December 31, 1960, for which the index or link-chain...

26 CFR 1.472-8 - Dollar-value method of pricing LIFO inventories.

Code of Federal Regulations, 2010 CFR

2010-04-01

... “link-chain” method will be approved for taxable years beginning after December 31, 1960, only in those... nature of the pool. A taxpayer using either an index or link-chain method shall attach to his income tax return for the first taxable year beginning after December 31, 1960, for which the index or link-chain...

26 CFR 1.472-8 - Dollar-value method of pricing LIFO inventories.

Code of Federal Regulations, 2012 CFR

2012-04-01

... “link-chain” method will be approved for taxable years beginning after December 31, 1960, only in those... nature of the pool. A taxpayer using either an index or link-chain method shall attach to his income tax return for the first taxable year beginning after December 31, 1960, for which the index or link-chain...

Central catalytic domain of BRAP (RNF52) recognizes the types of ubiquitin chains and utilizes oligo-ubiquitin for ubiquitylation.

PubMed

Shoji, Shisako; Hanada, Kazuharu; Ohsawa, Noboru; Shirouzu, Mikako

2017-09-07

Really interesting new gene (RING)-finger protein 52 (RNF52), an E3 ubiquitin ligase, is found in eukaryotes from yeast to humans. Human RNF52 is known as breast cancer type 1 susceptibility protein (BRCA1)-associated protein 2 (BRAP or BRAP2). The central catalytic domain of BRAP comprises four subdomains: nucleotide-binding α/β plait (NBP), really interesting new gene (RING) zinc finger, ubiquitin-specific protease (UBP)-like zinc finger (ZfUBP), and coiled-coil (CC). This domain architecture is conserved in RNF52 orthologs; however, the domain's function in the ubiquitin system has not been delineated. In the present study, we discovered that the RNF52 domain, comprising NBP-RING-ZfUBP-CC, binds to ubiquitin chains (oligo-ubiquitin) but not to the ubiquitin monomers, and can utilize various ubiquitin chains for ubiquitylation and auto-ubiquitylation. The RNF52 domain preferentially bound to M1- and K63-linked di-ubiquitin chains, weakly to K27-linked chains, but not to K6-, K11-, or K48-linked chains. The binding preferences of the RNF52 domain for ubiquitin-linkage types corresponded to ubiquitin usage in the ubiquitylation reaction, except for K11-, K29-, and K33-linked chains. Additionally, the RNF52 domain directly ligated the intact M1-linked, tri-, and tetra-ubiquitin chains and recognized the structural alterations caused by the phosphomimetic mutation of these ubiquitin chains. Full-length BRAP had nearly the same specificity for the ubiquitin-chain types as the RNF52 domain alone. Mass spectrometry analysis of oligomeric ubiquitylation products, mediated by the RNF52 domain, revealed that the ubiquitin-linkage types and auto-ubiquitylation sites depend on the length of ubiquitin chains. Here, we propose a model for the oligomeric ubiquitylation process, controlled by the RNF52 domain, which is not a sequential assembly process involving monomers. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Voltage droop Coordinating Control applied in UPFC and STATCOM system

NASA Astrophysics Data System (ADS)

Junhui, Huang; Zhuyi, Peng; Chengjie, Ni; Yiqing, Xu; Jiliang, Xue

2018-04-01

When UPFC, unified power flow controller is applied with other FACTS into power grid, it is possible that the voltage controlled vibrates constantly to response to a sudden reactive power turbulent in grid if the parameters of these FACTS are not coordinating reasonably. Moreover, the reactive power generated by these equipment will intertwine unexpectedly. The article proposes a method named voltage-reactive power droop control to allow the reference voltage fluctuating around the rating voltage so that the vibration is reduced and the power distribution is improved. Finally, the article cite a electric-magnetic simulation by EMTDC models of east-China power grid to prove it effective when applied to improve the response characteristics to sudden turbulence in power grid.

Linking matrices in systems with periodic boundary conditions

NASA Astrophysics Data System (ADS)

Panagiotou, Eleni; Millett, Kenneth C.

2018-06-01

We study the linking matrix, a measure of entanglement for a collection of closed or open chains in 3-space based on the Gauss linking number. Periodic boundary conditions (PBC) are often used in the simulation of physical systems of filaments. To measure entanglement of closed or open chains in systems employing PBC we use the periodic linking matrix, based on the periodic linking number, defined in Panagiotou (2015 J. Comput. Phys. 300 533–73). We study the properties of the periodic linking matrix as a function of cell size. We provide analytical results concerning the eigenvalues of the periodic linking matrix and show that some of them are invariant of cell-size.

Multi angle laser light scattering evaluation of field exposed thermoplastic photovoltaic encapsulant materials

DOE PAGES

Kempe, Michael D.; Miller, David C.; Wohlgemuth, John H.; ...

2016-01-08

As creep of polymeric materials is potentially a safety concern for photovoltaic modules, the potential for module creep has become a significant topic of discussion in the development of IEC 61730 and IEC 61215. To investigate the possibility of creep, modules were constructed, using several thermoplastic encapsulant materials, into thin-film mock modules and deployed in Mesa, Arizona. The materials examined included poly(ethylene)-co-vinyl acetate (EVA, including formulations both cross-linked and with no curing agent), polyethylene/polyoctene copolymer (PO), poly(dimethylsiloxane) (PDMS), polyvinyl butyral (PVB), and thermoplastic polyurethane (TPU). The absence of creep in this experiment is attributable to several factors of which themore » most notable one was the unexpected cross-linking of an EVA formulation without a cross-linking agent. It was also found that some materials experienced both chain scission and cross-linking reactions, sometimes with a significant dependence on location within a module. The TPU and EVA samples were found to degrade with cross-linking reactions dominating over chain scission. In contrast, the PO materials degraded with chain scission dominating over cross-linking reactions. Furthermore, we found no significant indications that viscous creep is likely to occur in fielded modules capable of passing the qualification tests, we note that one should consider how a polymer degrades, chain scission or cross-linking, in assessing the suitability of a thermoplastic polymer in terrestrial photovoltaic applications.« less

Foreign Languages: Key Links in the Chain of Learning.

ERIC Educational Resources Information Center

Mead, Robert G., Jr., Ed.

The articles discuss the necessity of including foreign language as an integral part of the curriculum at all levels of instruction. The following chapters are included: "Elementary School Foreign Language: Key Link in the Chain of Learning" (rationale, innovations, immersion programs, and interdisciplinary approaches); "Foreign…

The role of living/controlled radical polymerization in the formation of improved imprinted polymers.

PubMed

Salian, Vishal D; Vaughan, Asa D; Byrne, Mark E

2012-06-01

In this work, living/controlled radical polymerization (LRP) is compared with conventional free radical polymerization in the creation of highly and weakly cross-linked imprinted poly(methacrylic acid-co-ethylene glycol dimethacrylate) networks. It elucidates, for the first time, the effect of LRP on the chain level and begins to explain why the efficiency of the imprinting process is improved using LRP. Imprinted polymers produced via LRP exhibited significantly higher template affinity and capacity compared with polymers prepared using conventional methods. The use of LRP in the creation of highly cross-linked imprinted polymers resulted in a fourfold increase in binding capacity without a decrease in affinity; whereas weakly cross-linked gels demonstrated a nearly threefold increase in binding capacity at equivalent affinity when LRP was used. In addition, by adjusting the double bond conversion, we can choose to increase either the capacity or the affinity in highly cross-linked imprinted polymers, thus allowing the creation of imprinted polymers with tailorable binding parameters. Using free radical polymerization in the creation of polymer chains, as the template-monomer ratio increased, the average molecular weight of the polymer chains decreased despite a slight increase in the double bond conversion. Thus, the polymer chains formed were shorter but greater in number. Using LRP neutralized the effect of the template. The addition of chain transfer agent resulted in slow, uniform, simultaneous chain growth, resulting in the formation of longer more monodisperse chains. Reaction analysis revealed that propagation time was extended threefold in the formation of highly cross-linked polymers when LRP techniques were used. This delayed the transition to the diffusion-controlled stage of the reaction, which in turn led to the observed enhanced binding properties, decreased polydispersity in the chains, and a more homogeneous macromolecular architecture. Copyright © 2012 John Wiley & Sons, Ltd.

The coupling effects of kinematics and flexibility on the Lagrangian dynamic formulation of open chain deformable links

NASA Technical Reports Server (NTRS)

Changizi, Koorosh

1989-01-01

A nonlinear Lagrangian formulation for the spatial kinematic and dynamic analysis of open chain deformable links consisting of cylindrical joints that connect pairs of flexible links is developed. The special cases of revolute or prismatic joint can also be obtained from the kinematic equations. The kinematic equations are described using a 4x4 matrix method. The configuration of each deformable link in the open loop kinematic chain is identified using a coupled set of relative joint variables, constant geometric parameters, and elastic coordinates. The elastic coordinates define the link deformation with respect to a selected joint coordinate system that is consistent with the kinematic constraints on the boundary of the deformable link. These coordinates can be introduced using approximation techniques such as Rayleigh-Ritz method, finite element technique or any other desired approach. The large relative motion between two neighboring links are defined by a set of joint coordinates which describes the large relative translational and rotational motion between two neighboring joint coordinate systems. The origin of these coordinate systems are rigidly attached to the neighboring links at the joint definition points along the axis of motion.

Interaction of cholesterol with sphingomyelins and acyl-chain-matched phosphatidylcholines: a comparative study of the effect of the chain length.

PubMed Central

Ramstedt, B; Slotte, J P

1999-01-01

In this study we have synthesized sphingomyelins (SM) and phosphatidylcholines (PC) with amide-linked or sn-2 linked acyl chains with lengths from 14 to 24 carbons. The purpose was to examine how the chain length and degree of unsaturation affected the interaction of cholesterol with these phospholipids in model membrane systems. Monolayers of saturated SMs and PCs with acyl chain lengths above 14 carbons were condensed and displayed a high collapse pressure ( approximately 70 mN/m). Monolayers of N-14:0-SM and 1(16:0)-2(14:0)-PC had a much lower collapse pressure (58-60 mN/m) and monounsaturated SMs collapsed at approximately 50 mN/m. The relative interaction of cholesterol with these phospholipids was determined at 22 degreesC by measuring the rate of cholesterol desorption from mixed monolayers (50 mol % cholesterol; 20 mN/m) to beta-cyclodextrin in the subphase (1.7 mM). The rate of cholesterol desorption was lower from saturated SM monolayers than from chain-matched PC monolayers. In SM monolayers, the rate of cholesterol desorption was very slow for all N-linked chains, whereas for PC monolayers we could observe higher desorption rates from monolayers of longer PCs. These results show that cholesterol interacts favorably with SMs (low rate of desorption), whereas its interaction (or miscibility) with long chain PCs is weaker. Introduction of a single cis-unsaturation in the N-linked acyl chain of SMs led to faster rates of cholesterol desorption as compared with saturated SMs. The exception was monolayers of N-22:1-SM and N-24:1-SM from which cholesterol desorbed almost as slowly as from the corresponding saturated SM monolayers. The results of this study suggest that cholesterol is most likely capable of interacting with all physiologically relevant (including long-chain) SMs present in the plasma membrane of cells. PMID:9929492

Comparison of the crystal structures of methyl 4-bromo-2-(meth-oxy-meth-oxy)benzoate and 4-bromo-3-(meth-oxy-meth-oxy)benzoic acid.

PubMed

Suchetan, P A; Suneetha, V; Naveen, S; Lokanath, N K; Krishna Murthy, P

2016-04-01

The title compounds, C10H11BrO4, (I), and C9H9BrO4, (II), are derivatives of bromo-hy-droxy-benzoic acids. Compound (II) crystallizes with two independent mol-ecules (A and B) in the asymmetric unit. In both (I) and (II), the O-CH2-O-CH3 side chain is not in its fully extended conformation; the O-C-O-C torsion angle is 67.3 (3) ° in (I), and -65.8 (3) and -74.1 (3)° in mol-ecules A and B, respectively, in compound (II). In the crystal of (I), mol-ecules are linked by C-H⋯O hydrogen bonds, forming C(5) chains along [010]. The chains are linked by short Br⋯O contacts [3.047 (2) Å], forming sheets parallel to the bc plane. The sheets are linked via C-H⋯π inter-actions, forming a three-dimensional architecture. In the crystal of (II), mol-ecules A and B are linked to form R 2 (2)(8) dimers via two strong O-H⋯O hydrogen bonds. These dimers are linked into ⋯A-B⋯A-B⋯A-B⋯ [C 2 (2)(15)] chains along [011] by C-H⋯O hydrogen bonds. The chains are linked by slipped parallel π-π inter-actions [inter-centroid distances = 3.6787 (18) and 3.8431 (17) Å], leading to the formation of slabs parallel to the bc plane.

Crystal structures of three 3,4,5-tri-meth-oxy-benzamide-based derivatives.

PubMed

Gomes, Ligia R; Low, John Nicolson; Oliveira, Catarina; Cagide, Fernando; Borges, Fernanda

2016-05-01

The crystal structures of three benzamide derivatives, viz. N-(6-hy-droxy-hex-yl)-3,4,5-tri-meth-oxy-benzamide, C16H25NO5, (1), N-(6-anilinohex-yl)-3,4,5-tri-meth-oxy-benzamide, C22H30N2O4, (2), and N-(6,6-di-eth-oxy-hex-yl)-3,4,5-tri-meth-oxy-benzamide, C20H33NO6, (3), are described. These compounds differ only in the substituent at the end of the hexyl chain and the nature of these substituents determines the differences in hydrogen bonding between the mol-ecules. In each mol-ecule, the m-meth-oxy substituents are virtually coplanar with the benzyl ring, while the p-meth-oxy substituent is almost perpendicular. The carbonyl O atom of the amide rotamer is trans related with the amidic H atom. In each structure, the benzamide N-H donor group and O acceptor atoms link the mol-ecules into C(4) chains. In 1, a terminal -OH group links the mol-ecules into a C(3) chain and the combined effect of the C(4) and C(3) chains is a ribbon made up of screw related R 2 (2)(17) rings in which the ⋯O-H⋯ chain lies in the centre of the ribbon and the tri-meth-oxy-benzyl groups forms the edges. In 2, the combination of the benzamide C(4) chain and the hydrogen bond formed by the terminal N-H group to an O atom of the 4-meth-oxy group link the mol-ecules into a chain of R 2 (2)(17) rings. In 3, the mol-ecules are linked only by C(4) chains.

Optical probe for the cytochrome P-450 cholesterol side chain cleavage enzyme

DOEpatents

Marrone, Babetta L.; Simpson, Daniel J.; Unkefer, Clifford J.; Whaley, Thomas W.

1992-01-01

An optical probe enables the study of enzyme activity by absorbance spectroscopy or by sensitive fluorescence methods. In particular, the probe provides the ability to monitor the activity of cytochrome P-450.sub.scc enzyme, the rate limiting enzyme for steroid biosynthesis. Located on the inner mitochondrial membrane, P-450.sub.scc catalyzes the conversion of cholesterol to pregnenolone and isocapraldehyde by sequential oxidations of the cholesterol side chain. The fluorogenic probe includes a cholesterol-like steroid linked to a chromophore through a linking group. The chromophore is selected to have little optical response when linked to the steroid substrate and an enhanced optical response when cleaved from the substrate and linking group. Thus, a fluorescent anion that can be optically detected is generated by the side-chain cleavage reaction during steroidogenesis.

Optical probe for the cytochrome P-450 cholesterol side chain cleavage enzyme

DOEpatents

Marrone, Babetta L.; Simpson, Daniel J.; Unkefer, Clifford J.; Whaley, Thomas W.

1993-01-01

An optical probe enables the study of enzyme activity by absorbance spectroscopy or by sensitive fluorescence methods. In particular, the probe provides the ability to monitor the activity of cytochrome P-450.sub.scc enzyme, the rate limiting enzyme for steroid biosynthesis. Located on the inner mitochondrial membrane, P-450.sub.scc catalyzes the conversion of cholesterol to pregnenolone and isocapraldehyde by sequential oxidations of the cholesterol side chain. The fluorogenic probe includes a cholesterol-like steroid linked to a chromophore through a linking group. The chromophore is selected to have little optical response when linked to the steroid substrate and an enhanced optical response when cleaved from the substrate and linking group. Thus, a fluorescent anion that can be optically detected is generated by the side-chain cleavage reaction during steroidogenesis.

Self-generated covalent cross-links in the cell-surface adhesins of Gram-positive bacteria.

PubMed

Baker, Edward N; Squire, Christopher J; Young, Paul G

2015-10-01

The ability of bacteria to adhere to other cells or to surfaces depends on long, thin adhesive structures that are anchored to their cell walls. These structures include extended protein oligomers known as pili and single, multi-domain polypeptides, mostly based on multiple tandem Ig-like domains. Recent structural studies have revealed the widespread presence of covalent cross-links, not previously seen within proteins, which stabilize these domains. The cross-links discovered so far are either isopeptide bonds that link lysine side chains to the side chains of asparagine or aspartic acid residues or ester bonds between threonine and glutamine side chains. These bonds appear to be formed by spontaneous intramolecular reactions as the proteins fold and are strategically placed so as to impart considerable mechanical strength. © 2015 Authors; published by Portland Press Limited.

Maximum Kolmogorov-Sinai Entropy Versus Minimum Mixing Time in Markov Chains

NASA Astrophysics Data System (ADS)

Mihelich, M.; Dubrulle, B.; Paillard, D.; Kral, Q.; Faranda, D.

2018-01-01

We establish a link between the maximization of Kolmogorov Sinai entropy (KSE) and the minimization of the mixing time for general Markov chains. Since the maximisation of KSE is analytical and easier to compute in general than mixing time, this link provides a new faster method to approximate the minimum mixing time dynamics. It could be interesting in computer sciences and statistical physics, for computations that use random walks on graphs that can be represented as Markov chains.

Effect of pendent chains on the interfacial properties of thin polydimethylsiloxane (PDMS) networks.

PubMed

Landherr, Lucas J T; Cohen, Claude; Archer, Lynden A

2011-05-17

The interfacial properties of end-linked polydimethylsiloxane (PDMS) films on silicon are examined. Thin cross-linked PDMS films (∼10 μm thick) were synthesized over a self-assembled monolayer supported on a silicon wafer. By systematically varying the concentration of monofunctional PDMS in a mixture with telechelic precursor molecules, structures ranging from near-ideal elastic networks to poorly cross-linked networks composed of a preponderance of dangling/pendent chains were synthesized. Lateral force microscopy (LFM) employing bead probes was used to quantify the effect of network structure on the interfacial friction coefficient and residual force. Indentation measurements employing an AFM in force mode were used to characterize the elastic modulus and the pull-off force for the films as a function of pendent chain content. These measurements were complemented with conventional mechanical rheometry measurements on similar thick network films to determine their bulk rheological properties. All networks studied manifested interfacial friction coefficients substantially lower than that of bare silicon. PDMS networks with the lowest pendent chain content displayed friction coefficients close to 1 order of magnitude lower than that of bare silicon, whereas networks with the highest pendent chain content manifested friction coefficients about 3 times lower than that of bare silicon. At intermediate sliding velocities, a crossover in the interfacial friction coefficient was observed, wherein cross-linked PDMS films with the least amount of pendent chains exhibit the highest friction coefficient. These observations are discussed in terms of the structure of the films and relaxation dynamics of elastic strands and dangling chains in tethered network films.

Choice and conditioned reinforcement.

PubMed Central

Fantino, E; Freed, D; Preston, R A; Williams, W A

1991-01-01

A potential weakness of one formulation of delay-reduction theory is its failure to include a term for rate of conditioned reinforcement, that is, the rate at which the terminal-link stimuli occur in concurrent-chains schedules. The present studies assessed whether or not rate of conditioned reinforcement has an independent effect upon choice. Pigeons responded on either modified concurrent-chains schedules or on comparable concurrent-tandem schedules. The initial link was shortened on only one of two concurrent-chains schedules and on only one of two corresponding concurrent-tandem schedules. This manipulation increased rate of conditioned reinforcement sharply in the chain but not in the tandem schedule. According to a formulation of delay-reduction theory, when the outcomes chosen (the terminal links) are equal, as in Experiment 1, choice should depend only on rate of primary reinforcement; thus, choice should be equivalent for the tandem and chain schedules despite a large difference in rate of conditioned reinforcement. When the outcomes chosen are unequal, however, as in Experiment 2, choice should depend upon both rate of primary reinforcement and relative signaled delay reduction; thus, larger preferences should occur in the chain than in the tandem schedules. These predictions were confirmed, suggesting that increasing the rate of conditioned reinforcement on concurrent-chains schedules may have no independent effect on choice. PMID:2037826

The Chain-Link Fence Model: A Framework for Creating Security Procedures

ERIC Educational Resources Information Center

Houghton, Robert F.

2013-01-01

A long standing problem in information technology security is how to help reduce the security footprint. Many specific proposals exist to address specific problems in information technology security. Most information technology solutions need to be repeatable throughout the course of an information systems lifecycle. The Chain-Link Fence Model is…

Interfacial friction and adhesion of cross-linked polymer thin films swollen with linear chains.

PubMed

Zhang, Qing; Archer, Lynden A

2007-07-03

The preparation and interfacial properties of a new type of tethered, thin-film lubricant coating are presented. These coatings are composed of three components: a dense self-assembled monolayer (SAM) underlayer that presents reactive vinyl groups at its surface; a cross-linked polydimethylsiloxane (PDMS) overlayer that is covalently tethered to the SAM; and free, mobile linear PDMS chains dispersed in the network. We investigate the influence of the molecular weight (Ms) and concentration of the free PDMS chains on the structure and equilibrium swelling properties of the cross-linked films. Using a bead-probe lateral force microscopy measurement technique, we also quantify the interfacial friction and adhesion characteristics of surfaces functionalized with these coatings. We find that both the volume fraction and the molecular weight of free PDMS molecules in the coatings influence their interfacial friction and adhesion properties. For example, the addition of short PDMS chains in dry, cross-linked PDMS thin films yields tethered surface coatings with ultralow friction coefficients (mu = 5.2 x 10(-3)). An analysis based on classical lubrication theory suggests that the reduction in friction force produced by free polymer is a consequence of the gradual separation of asperities on opposing surfaces and the consequent substitution of solid-solid friction by viscous drag of the free polymer chains in the network.

Novel polyubiquitin imaging system, PolyUb-FC, reveals that K33-linked polyubiquitin is recruited by SQSTM1/p62.

PubMed

Nibe, Yoichi; Oshima, Shigeru; Kobayashi, Masanori; Maeyashiki, Chiaki; Matsuzawa, Yu; Otsubo, Kana; Matsuda, Hiroki; Aonuma, Emi; Nemoto, Yasuhiro; Nagaishi, Takashi; Okamoto, Ryuichi; Tsuchiya, Kiichiro; Nakamura, Tetsuya; Nakada, Shinichiro; Watanabe, Mamoru

2018-01-01

Ubiquitin chains are formed with 8 structurally and functionally distinct polymers. However, the functions of each polyubiquitin remain poorly understood. We developed a polyubiquitin-mediated fluorescence complementation (PolyUb-FC) assay using Kusabira Green (KG) as a split fluorescent protein. The PolyUb-FC assay has the advantage that monoubiquitination is nonfluorescent and chain-specific polyubiquitination can be directly visualized in living cells without using antibodies. We applied the PolyUb-FC assay to examine K33-linked polyubiquitin. We demonstrated that SQSTM1/p62 puncta colocalized with K33-linked polyubiquitin and this interaction was modulated by the ZRANB1/TRABID-K29 and -K33 linkage-specific deubiquitinase (DUB). We further showed that the colocalization of K33-linked polyubiquitin and MAP1LC3/LC3 (microtubule associated protein 1 light chain 3) puncta was impaired by SQSTM1/p62 deficiency. Taken together, these findings provide novel insights into how atypical polyubiquitin is recruited by SQSTM1/p62. Finally, we developed an inducible-PolyUb-FC system for visualizing chain-specific polyubiquitin. The PolyUb-FC will be a useful tool for analyzing the dynamics of atypical polyubiquitin chain generation.

Track with overlapping links for dry coal extrusion pumps

DOEpatents

Saunders, Timothy; Brady, John D

2014-01-21

A chain for a particulate material extrusion pump includes a plurality of links, each of the plurality of links having a link body and a link ledge, wherein each link ledge of the plurality of links at least partially overlaps the link body of an adjacent one of the plurality of links.

The Effect of Conditioned Reinforcement Rate on Choice: A Review

PubMed Central

Fantino, Edmund; Romanowich, Paul

2007-01-01

We review the nature of conditioned reinforcement, including evidence that conditioned reinforcers maintain choice behavior in concurrent schedules and that they elevate responding in the terminal links of concurrent-chains schedules. A question has resurfaced recently: Do theories of choice in concurrent-chains schedules need to include a term reflecting greater preference for higher rates of conditioned reinforcement? The review of several studies addressing this point suggests that such a term is inappropriate. Elevated rates of conditioned reinforcement (and responding) in the terminal links of concurrent-chains schedules do not lead to greater preference in the initial link leading to the higher rate of conditioned reinforcement. If anything, the opposite preference is likely to occur. This result is not surprising, since the additional putative conditioned reinforcers in the terminal link are not correlated with a reduction in time to primary reinforcement nor with an increase in value. PMID:17575906

Carbamate-linked cationic lipids with different hydrocarbon chains for gene delivery.

PubMed

Shi, Jia; Yu, Shijun; Zhu, Jie; Zhi, Defu; Zhao, Yinan; Cui, Shaohui; Zhang, Shubiao

2016-05-01

A series of carbamate-linked cationic lipids containing saturated or unsaturated hydrocarbon chains and quaternary ammonium head were designed and synthesized. After recrystallization, carbamate-linked cationic lipids with high purity (over 95%) were obtained. The structures of these lipids were proved by IR spectrum, HR-ESI-MS, HPLC, (1)H NMR and (13)C NMR. The liposomes were prepared by using these cationic lipids and neutral lipid DOPE. Particle size and zeta-potential were studied to show that they were suitable for gene transfection. The DNA-bonding ability of C12:0, C14:0 and C18:1 cationic liposomes was much better than others. The results of transfection showed that hydrophobic chains of these lipids have great effects on their transfection activity. The lipids bearing C12:0, C14:0 saturated chains or C18:1 unsaturated chain showed relatively higher transfection efficiency and lower cytotoxicity. So these cationic lipids could be used as non-viral gene carriers for further studies. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of the One- and Bi-Direction Chained Equipercentile Equating

ERIC Educational Resources Information Center

Oh, Hyeonjoo; Moses, Tim

2012-01-01

This study investigated differences between two approaches to chained equipercentile (CE) equating (one- and bi-direction CE equating) in nearly equal groups and relatively unequal groups. In one-direction CE equating, the new form is linked to the anchor in one sample of examinees and the anchor is linked to the reference form in the other…

Rapid Acquisition in Concurrent Chains: Evidence for a Decision Model

ERIC Educational Resources Information Center

Grace, Randolph C.; McLean, Anthony P.

2006-01-01

Pigeons' choice in concurrent chains can adapt to rapidly changing contingencies. Grace, Bragason, and McLean (2003) found that relative initial-link response rate was sensitive to the immediacy ratio in the current session when one of the terminal-link fixed-interval schedules was changed daily according to a pseudorandom binary sequence (e.g.,…

Tunneling conductance of amine-linked alkyl chains.

PubMed

Prodan, Emil; Car, Roberto

2008-06-01

The tunneling transport theory developed in ref 9 (Phys. Rev. B 2007, 76, 115102) is applied to molecular devices made of alkyl chains linked to gold electrodes via amine groups. Using the analytic expression of the tunneling conductance derived in our previous work, we identify the key physical quantities that characterize the conductance of these devices. By investigating the transport characteristics of three devices, containing four, six, and eight methyl groups, we extract the dependence of the tunneling conductance on the chain's length, which is an exponential decay law in agreement with recent experimental data.

Stepwise Elastic Behavior in a Model Elastomer

NASA Astrophysics Data System (ADS)

Bhawe, Dhananjay M.; Cohen, Claude; Escobedo, Fernando A.

2004-12-01

MonteCarlo simulations of an entanglement-free cross-linked polymer network of semiflexible chains reveal a peculiar stepwise elastic response. For increasing stress, step jumps in strain are observed that do not correlate with changes in the number of aligned chains. We show that this unusual behavior stems from the ability of the system to form multiple ordered chain domains that exclude the cross-linking species. This novel elastomer shows a toughening behavior similar to that observed in biological structural materials, such as muscle proteins and abalone shell adhesive.

Unique anthranilic acid chemistry facilitates profiling and characterization of Ser/Thr-linked sugar chains following hydrazinolysis.

PubMed

Anumula, Kalyan Rao

2008-02-01

A novel method for the analysis of Ser/Thr-linked sugar chains was made possible by the virtue of unique anthranilic acid (AA, 2-aminobenzoic acid [2AA]) chemistry for labeling carbohydrates in aqueous salt solutions (K. R. Anumula, Anal. Biochem. 350 (2006) 1-23). The protocol for profiling of Ser/Thr carbohydrates by hydrazinolysis was made simple by eliminating intermediary isolation steps involved in a sample preparation such as desalting and various chromatographic purification schemes. A 6-h hydrazinolysis was carried out at 60 degrees C for O-linked oligosaccharides and at 95 degrees C for total oligosaccharides (N-linked with some O-linked). Following evaporation of hydrazine (<10 min), the oligosaccharides were N-acetylated and derivatized with AA in the same reaction mixture containing salts. Presumably, the glycosyl-hydrazines/hydrazones present in the mixture did not interfere with AA labeling. Because AA is the most fluorescent and highly reactive tag for labeling carbohydrates, the procedures described are suitable for the analysis of a limited amount of samples ( approximately 5 microg) by the current high-resolution high-performance liquid chromatography (HPLC) methods. HPLC conditions developed for the separation of O-linked sugar chains based on size on an amide column were satisfactory for quantitative profiling and characterization. Common O-linked sugar chains found in fetuin, equine chorionic gonadotropin, and glycophorin can be analyzed in less than 50 min. In addition, these fast profiling methods were comparable to profiling by PNGase F (peptide N-glycosidase from Flavobacterium meningosepticum) digestion in terms of time, effort, and simplicity and also were highly reproducible for routine testing. The procedures for the release of sugar chains by hydrazinolysis at the microgram level, labeling with fluorescent tag AA, and profiling by HPLC should be useful in characterization of carbohydrates found in glycoproteins.

TRIM5α requires Ube2W to anchor Lys63-linked ubiquitin chains and restrict reverse transcription

PubMed Central

Fletcher, Adam J; Christensen, Devin E; Nelson, Chad; Tan, Choon Ping; Schaller, Torsten; Lehner, Paul J; Sundquist, Wesley I; Towers, Greg J

2015-01-01

TRIM5α is an antiviral, cytoplasmic, E3 ubiquitin (Ub) ligase that assembles on incoming retroviral capsids and induces their premature dissociation. It inhibits reverse transcription of the viral genome and can also synthesize unanchored polyubiquitin (polyUb) chains to stimulate innate immune responses. Here, we show that TRIM5α employs the E2 Ub-conjugating enzyme Ube2W to anchor the Lys63-linked polyUb chains in a process of TRIM5α auto-ubiquitination. Chain anchoring is initiated, in cells and in vitro, through Ube2W-catalyzed monoubiquitination of TRIM5α. This modification serves as a substrate for the elongation of anchored Lys63-linked polyUb chains, catalyzed by the heterodimeric E2 enzyme Ube2N/Ube2V2. Ube2W targets multiple TRIM5α internal lysines with Ub especially lysines 45 and 50, rather than modifying the N-terminal amino group, which is instead αN-acetylated in cells. E2 depletion or Ub mutation inhibits TRIM5α ubiquitination in cells and restores restricted viral reverse transcription, but not infection. Our data indicate that the stepwise formation of anchored Lys63-linked polyUb is a critical early step in the TRIM5α restriction mechanism and identify the E2 Ub-conjugating cofactors involved. PMID:26101372

The Advancement Value Chain: An Exploratory Model

ERIC Educational Resources Information Center

Leonard, Edward F., III

2005-01-01

Since the introduction of the value chain concept in 1985, several varying, yet virtually similar, value chains have been developed for the business enterprise. Shifting to higher education, can a value chain be found that links together the various activities of advancement so that an institution's leaders can actually look at the philanthropic…

77 FR 17001 - USDA Public Stakeholder Meeting: Match Making in the Biofuels Value Chain

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-23

... to improve awareness and increase understanding of the biofuels supply chain links between all those.... At this meeting, federal officials will provide a short profile of each section of the supply chain... that outline their experiences in that respective supply chain sector, barriers and lessons learned...

On Farm and Packhouse: Employment at the Bottom of a Global Value Chain

ERIC Educational Resources Information Center

Dolan, Catherine S.

2004-01-01

The fresh vegetables commodity chain linking Kenyan producers with United Kingdom (UK) consumers employs significant numbers of workers in production and processing. This chain is dominated by UK retailers that determine the production imperatives of Kenyan firms upstream in the chain and, indirectly the employment strategies they adopt. This…

Rapid Acquisition of Preference in Concurrent Chains: Effects of "d"-Amphetamine on Sensitivity to Reinforcement Delay

ERIC Educational Resources Information Center

Ta, Wei-Min; Pitts, Raymond C.; Hughes, Christine E.; McLean, Anthony P.; Grace, Randolph C.

2008-01-01

The purpose of this study was to examine effects of "d"-amphetamine on choice controlled by reinforcement delay. Eight pigeons responded under a concurrent-chains procedure in which one terminal-link schedule was always fixed- interval 8 s, and the other terminal-link schedule changed from session to session between fixed-interval 4 s and…

A new assessment of the alleged link between element 115 and element 117 decay chains

NASA Astrophysics Data System (ADS)

Forsberg, U.; Rudolph, D.; Fahlander, C.; Golubev, P.; Sarmiento, L. G.; Åberg, S.; Block, M.; Düllmann, Ch. E.; Heßberger, F. P.; Kratz, J. V.; Yakushev, A.

2016-09-01

A novel rigorous statistical treatment is applied to available data (May 9, 2016) from search and spectroscopy experiments on the elements with atomic numbers Z = 115 and Z = 117. The present analysis implies that the hitherto proposed cross-reaction link between α-decay chains associated with the isotopes 293117 and 289115 is highly improbable.

Quasi-multi-pulse voltage source converter design with two control degrees of freedom

NASA Astrophysics Data System (ADS)

Vural, A. M.; Bayindir, K. C.

2015-05-01

In this article, the design details of a quasi-multi-pulse voltage source converter (VSC) switched at line frequency of 50 Hz are given in a step-by-step process. The proposed converter is comprised of four 12-pulse converter units, which is suitable for the simulation of single-/multi-converter flexible alternating current transmission system devices as well as high voltage direct current systems operating at the transmission level. The magnetic interface of the converter is originally designed with given all parameters for 100 MVA operation. The so-called two-angle control method is adopted to control the voltage magnitude and the phase angle of the converter independently. PSCAD simulation results verify both four-quadrant converter operation and closed-loop control of the converter operated as static synchronous compensator (STATCOM).

Crystal structures of three 3,4,5-tri­meth­oxy­benzamide-based derivatives

PubMed Central

Gomes, Ligia R.; Low, John Nicolson; Oliveira, Catarina; Cagide, Fernando; Borges, Fernanda

2016-01-01

The crystal structures of three benzamide derivatives, viz. N-(6-hy­droxy­hex­yl)-3,4,5-tri­meth­oxy­benzamide, C16H25NO5, (1), N-(6-anilinohex­yl)-3,4,5-tri­meth­oxy­benzamide, C22H30N2O4, (2), and N-(6,6-di­eth­oxy­hex­yl)-3,4,5-tri­meth­oxy­benzamide, C20H33NO6, (3), are described. These compounds differ only in the substituent at the end of the hexyl chain and the nature of these substituents determines the differences in hydrogen bonding between the mol­ecules. In each mol­ecule, the m-meth­oxy substituents are virtually coplanar with the benzyl ring, while the p-meth­oxy substituent is almost perpendicular. The carbonyl O atom of the amide rotamer is trans related with the amidic H atom. In each structure, the benzamide N—H donor group and O acceptor atoms link the mol­ecules into C(4) chains. In 1, a terminal –OH group links the mol­ecules into a C(3) chain and the combined effect of the C(4) and C(3) chains is a ribbon made up of screw related R 2 2(17) rings in which the ⋯O—H⋯ chain lies in the centre of the ribbon and the tri­meth­oxy­benzyl groups forms the edges. In 2, the combination of the benzamide C(4) chain and the hydrogen bond formed by the terminal N—H group to an O atom of the 4-meth­oxy group link the mol­ecules into a chain of R 2 2(17) rings. In 3, the mol­ecules are linked only by C(4) chains. PMID:27308017

Aluminum-induced dreierketten chain cross-links increase the mechanical properties of nanocrystalline calcium aluminosilicate hydrate

NASA Astrophysics Data System (ADS)

Geng, Guoqing; Myers, Rupert J.; Li, Jiaqi; Maboudian, Roya; Carraro, Carlo; Shapiro, David A.; Monteiro, Paulo J. M.

2017-03-01

The incorporation of Al and increased curing temperature promotes the crystallization and cross-linking of calcium (alumino)silicate hydrate (C-(A-)S-H), which is the primary binding phase in most contemporary concrete materials. However, the influence of Al-induced structural changes on the mechanical properties at atomistic scale is not well understood. Herein, synchrotron radiation-based high-pressure X-ray diffraction is used to quantify the influence of dreierketten chain cross-linking on the anisotropic mechanical behavior of C-(A-)S-H. We show that the ab-planar stiffness is independent of dreierketten chain defects, e.g. vacancies in bridging tetrahedra sites and Al for Si substitution. The c-axis of non-cross-linked C-(A-)S-H is more deformable due to the softer interlayer opening but stiffens with decreased spacing and/or increased zeolitic water and Ca2+ of the interlayer. Dreierketten chain cross-links act as ‘columns’ to resist compression, thus increasing the bulk modulus of C-(A-)S-H. We provide the first experimental evidence on the influence of the Al-induced atomistic configurational change on the mechanical properties of C-(A-)S-H. Our work advances the fundamental knowledge of C-(A-)S-H on the lowest level of its hierarchical structure, and thus can impact the way that innovative C-(A-)S-H-based cementitious materials are developed using a ‘bottom-up’ approach.

Aluminum-induced dreierketten chain cross-links increase the mechanical properties of nanocrystalline calcium aluminosilicate hydrate.

PubMed

Geng, Guoqing; Myers, Rupert J; Li, Jiaqi; Maboudian, Roya; Carraro, Carlo; Shapiro, David A; Monteiro, Paulo J M

2017-03-10

The incorporation of Al and increased curing temperature promotes the crystallization and cross-linking of calcium (alumino)silicate hydrate (C-(A-)S-H), which is the primary binding phase in most contemporary concrete materials. However, the influence of Al-induced structural changes on the mechanical properties at atomistic scale is not well understood. Herein, synchrotron radiation-based high-pressure X-ray diffraction is used to quantify the influence of dreierketten chain cross-linking on the anisotropic mechanical behavior of C-(A-)S-H. We show that the ab-planar stiffness is independent of dreierketten chain defects, e.g. vacancies in bridging tetrahedra sites and Al for Si substitution. The c-axis of non-cross-linked C-(A-)S-H is more deformable due to the softer interlayer opening but stiffens with decreased spacing and/or increased zeolitic water and Ca 2+ of the interlayer. Dreierketten chain cross-links act as 'columns' to resist compression, thus increasing the bulk modulus of C-(A-)S-H. We provide the first experimental evidence on the influence of the Al-induced atomistic configurational change on the mechanical properties of C-(A-)S-H. Our work advances the fundamental knowledge of C-(A-)S-H on the lowest level of its hierarchical structure, and thus can impact the way that innovative C-(A-)S-H-based cementitious materials are developed using a 'bottom-up' approach.

Characterization of the Deoxyguanosine–Lysine Cross-Link of Methylglyoxal

PubMed Central

2015-01-01

Methylglyoxal is a mutagenic bis-electrophile that is produced endogenously from carbohydrate precursors. Methylglyoxal has been reported to induce DNA–protein cross-links (DPCs) in vitro and in cultured cells. Previous work suggests that these cross-links are formed between guanine and either lysine or cysteine side chains. However, the chemical nature of the methylglyoxal induced DPC have not been determined. We have examined the reaction of methylglyoxal, deoxyguanosine (dGuo), and Nα-acetyllysine (AcLys) and determined the structure of the cross-link to be the N2-ethyl-1-carboxamide with the lysine side chain amino group (1). The cross-link was identified by mass spectrometry and the structure confirmed by comparison to a synthetic sample. Further, the cross-link between methylglyoxal, dGuo, and a peptide (AcAVAGKAGAR) was also characterized. The mechanism of cross-link formation is likely to involve an Amadori rearrangement. PMID:24801980

Phase Transition in Biopolymer Hydrogels Based on Glycine (g), Valine (v), Proline (p), and Isoleucine (i)

NASA Astrophysics Data System (ADS)

Lee, Jonghwi; Urry, Dan W.; Macosko, Christopher W.

2000-03-01

Selectively modified elastic protein-based polymers demonstrate diverse energy conversions by means of the control of a phase transition resulting from the sensitivity to stimuli of the hydrophobic association. Among these polymers, poly(GVGVP), poly(GVGIP) and analogues of poly(GVGVP) containing carboxylic acid or amino functional groups as side chains were cross-linked and their swelling behavior was studied. Regardless of cross-linking method, reversible phase transitions can be observed in the swelling of all cross-linked polymers by changing temperature and pH, where relevant. Decreased cross-link density leads to increased swelling ratio as the transition becomes more pronounced. Fibers, chemically cross-linked after formation, exhibit anisotropic dimensional changes on changing the temperature. Gamma-irradiation cross-linked poly(GVGVP) exhibited a more distinct phase transition than modified poly(GVGVP) with ion pairs between side chains, which were partially converted to amide cross-links.

Locations of Racism in Education: A Speech Act Analysis of a Policy Chain

ERIC Educational Resources Information Center

Arneback, Emma; Quennerstedt, Ann

2016-01-01

This article explores how racism is located in an educational policy chain and identifies how its interpretation changes throughout the chain. A basic assumption is that the policy formation process can be seen as a chain in which international, national and local policies are "links"--separate entities yet joined. With Sweden as the…

Mass spectrometric method to determine the chain length of oligosaccharides attached to phenolic polymers by nonglycosidic linkages

Treesearch

James L. Minor; Roger C. Pettersen

1987-01-01

In many plants, a portion of the polysaccharides appears to have a very low degree of cross-linking with aromatic polymers such as lignin or flavolans. The proportion of cross-linked units may be enriched for study by enzymatically hydrolyzing the nonbonded carbohydrates. A convenient method is described for the simultaneous analysis of sugar content and apparent chain...

Rapid Acquisition of Preference in Concurrent Chains when Alternatives Differ on Multiple Dimensions of Reinforcement

ERIC Educational Resources Information Center

Kyonka, Elizabeth G. E.; Grace, Randolph C.

2008-01-01

Pigeons responded in a concurrent-chains procedure in which terminal-link reinforcer variables were changed unpredictably across sessions. In Experiment 1, the terminal-link schedules were fixed-interval (FI) 8 s and FI 16 s, and the reinforcer magnitudes were 2 s and 4 s. In Experiment 2 the probability of reinforcement (100% or 50%) was varied…

On extinction time of a generalized endemic chain-binomial model.

PubMed

Aydogmus, Ozgur

2016-09-01

We considered a chain-binomial epidemic model not conferring immunity after infection. Mean field dynamics of the model has been analyzed and conditions for the existence of a stable endemic equilibrium are determined. The behavior of the chain-binomial process is probabilistically linked to the mean field equation. As a result of this link, we were able to show that the mean extinction time of the epidemic increases at least exponentially as the population size grows. We also present simulation results for the process to validate our analytical findings. Copyright © 2016 Elsevier Inc. All rights reserved.

Weak reversible cross links may decrease the strength of aligned fiber bundles.

PubMed

Nabavi, S Soran; Hartmann, Markus A

2016-02-21

Reversible cross-linking is an effective strategy to specifically tailor the mechanical properties of polymeric materials that can be found in a variety of biological as well as man-made materials. Using a simple model in this paper the influence of weak, reversible cross-links on the mechanical properties of aligned fiber bundles is investigated. Special emphasis in this analysis is put on the strength of the investigated structures. Using Monte Carlo methods two topologies of cross-links exceeding the strength of the covalent backbone are studied. Most surprisingly only two cross-links are sufficient to break the backbone of a multi chain system, resulting in a reduced strength of the material. The found effect crucially depends on the ratio of inter- to intra-chain cross-links and, thus, on the grafting density that determines this ratio.

The A-chain of insulin contacts the insert domain of the insulin receptor. Photo-cross-linking and mutagenesis of a diabetes-related crevice.

PubMed

Huang, Kun; Chan, Shu Jin; Hua, Qing-xin; Chu, Ying-Chi; Wang, Run-ying; Klaproth, Birgit; Jia, Wenhua; Whittaker, Jonathan; De Meyts, Pierre; Nakagawa, Satoe H; Steiner, Donald F; Katsoyannis, Panayotis G; Weiss, Michael A

2007-11-30

The contribution of the insulin A-chain to receptor binding is investigated by photo-cross-linking and nonstandard mutagenesis. Studies focus on the role of Val(A3), which projects within a crevice between the A- and B-chains. Engineered receptor alpha-subunits containing specific protease sites ("midi-receptors") are employed to map the site of photo-cross-linking by an analog containing a photoactivable A3 side chain (para-azido-Phe (Pap)). The probe cross-links to a C-terminal peptide (residues 703-719 of the receptor A isoform, KTFEDYLHNVVFVPRPS) containing side chains critical for hormone binding (underlined); the corresponding segment of the holoreceptor was shown previously to cross-link to a Pap(B25)-insulin analog. Because Pap is larger than Val and so may protrude beyond the A3-associated crevice, we investigated analogs containing A3 substitutions comparable in size to Val as follows: Thr, allo-Thr, and alpha-aminobutyric acid (Aba). Substitutions were introduced within an engineered monomer. Whereas previous studies of smaller substitutions (Gly(A3) and Ser(A3)) encountered nonlocal conformational perturbations, NMR structures of the present analogs are similar to wild-type insulin; the variant side chains are accommodated within a native-like crevice with minimal distortion. Receptor binding activities of Aba(A3) and allo-Thr(A3) analogs are reduced at least 10-fold; the activity of Thr(A3)-DKP-insulin is reduced 5-fold. The hormone-receptor interface is presumably destabilized either by a packing defect (Aba(A3)) or by altered polarity (allo-Thr(A3) and Thr(A3)). Our results provide evidence that Val(A3), a site of mutation causing diabetes mellitus, contacts the insert domain-derived tail of the alpha-subunit in a hormone-receptor complex.

Purification and characterization of highly branched α-glucan-producing enzymes from Paenibacillus sp. PP710.

PubMed

Tsusaki, Keiji; Watanabe, Hikaru; Yamamoto, Takuo; Nishimoto, Tomoyuki; Chaen, Hiroto; Fukuda, Shigeharu

2012-01-01

Highly branched α-glucan molecules exhibit low digestibility for α-amylase and glucoamylase, and abundant in α-(1→3)-, α-(1→6)-glucosidic linkages and α-(1→6)-linked branch points where another glucosyl chain is initiated through an α-(1→3)-linkage. From a culture supernatant of Paenibacillus sp. PP710, we purified α-glucosidase (AGL) and α-amylase (AMY), which were involved in the production of highly branched α-glucan from maltodextrin. AGL catalyzed the transglucosylation reaction of a glucosyl residue to a nonreducing-end glucosyl residue by α-1,6-, α-1,4-, and α-1,3-linkages. AMY catalyzed the hydrolysis of the α-1,4-linkage and the intermolecular or intramolecular transfer of maltooligosaccharide like cyclodextrin glucanotransferase (CGTase). It also catalyzed the transfer of an α-1,4-glucosyl chain to a C3- or C4-hydroxyl group in the α-1,4- or α-1,6-linked nonreducing-end residue or the α-1,6-linked residue located in the other chains. Hence AMY was regarded as a novel enzyme. We think that the mechanism of formation of highly branched α-glucan from maltodextrin is as follows: α-1,6- and α-1,3-linked residues are generated by the transglucosylation of AGL at the nonreducing ends of glucosyl chains. Then AMY catalyzes the transfer of α-1,4-chains to C3- or C4-hydroxyl groups in the α-1,4- or α-1,6-linked residues generated by AGL. Thus the concerted reactions of both AGL and AMY are necessary to produce the highly branched α-glucan from maltodextrin.

We need to include bystander first aid in trauma research.

PubMed

Bakke, Håkon Kvåle; Wisborg, Torben

2017-03-23

The chain of trauma survival is a concept that originated in the area of out-of-hospital cardiac arrest (OHCA) and was adapted to the treatment of trauma. In out-of-hospital cardiac arrest research into bystander first aid has resulted in improved outcome. Whereas, in trauma research the first link of the chain of survival is almost ignored. In OHCA, cardiopulmonary resuscitation (CPR) from bystanders has been subject of a vast amount of research, as well as measures and programs to raise the rate of bystander CPR to cardiac arrest victims. These efforts have resulted in improved survival. The research effort has been well grounded in the research community, as demonstrated by its natural inclusion in the uniform reporting template (Utstein) for the treatment of OHCA. In trauma the bystander may contribute by providing an open airway, staunch bleedings, or prevent hypothermia. In trauma however, while the chain of survival has been adopted along with it distinct links, including bystander first aid, the consensus-based uniform reporting template for trauma (the Utstein template) does not include the bystander first aid efforts. There is extremely little research on what first aid measures bystanders provide to trauma victims, and on what impact such measures have on outcome. An important step to improve research on bystander first aid in trauma would be to include this as part of the uniform reporting template for trauma CONCLUSION: The lack of research on bystander first aid makes the first link in the trauma chain of survival the weakest link. We, the trauma research community, should either improve our research and knowledge in this area, or remove the link from the chain of survival.

New Directions in Online Fraud

NASA Astrophysics Data System (ADS)

Mohatar, Oscar Delgado; Sierra Cámara, José M.

2007-12-01

The security of a system can be seen as a chain of protection methods, and the global level is just as strong as its weakest link. From this point of view, cryptography is no more than other link in the chain. And most of the times, it is probably the strongest link, but there are many others weak links which decrease the security level until unacceptable level for carrying out electronic commerce. In last term, exclusively technical protection methods seem not be able to completely resolve the situation. The focus should be changed towards trying to increase the resistance of the system, instead of its invulnerability that, in any case, can not be completely achieved in general purpose operating systems.

2-qubit quantum state transfer in spin chains and cold atoms with weak links

NASA Astrophysics Data System (ADS)

Lorenzo, Salvatore; Apollaro, Tony J. G.; Trombettoni, Andrea; Paganelli, Simone

In this paper we discuss the implementation of 2-qubit quantum state transfer (QST) in inhomogeneous spin chains where the sender and the receiver blocks are coupled through the bulk channel via weak links. The fidelity and the typical timescale of the QST are discussed as a function of the parameters of the weak links. Given the possibility of implementing with cold atoms in optical lattices a variety of condensed matter systems, including spin systems, we also discuss the possible implementation of the discussed 2-qubit QST with cold gases with weak links, together with a discussion of the applications and limitations of the presented results.

3D printed soft parallel actuator

NASA Astrophysics Data System (ADS)

Zolfagharian, Ali; Kouzani, Abbas Z.; Khoo, Sui Yang; Noshadi, Amin; Kaynak, Akif

2018-04-01

This paper presents a 3-dimensional (3D) printed soft parallel contactless actuator for the first time. The actuator involves an electro-responsive parallel mechanism made of two segments namely active chain and passive chain both 3D printed. The active chain is attached to the ground from one end and constitutes two actuator links made of responsive hydrogel. The passive chain, on the other hand, is attached to the active chain from one end and consists of two rigid links made of polymer. The actuator links are printed using an extrusion-based 3D-Bioplotter with polyelectrolyte hydrogel as printer ink. The rigid links are also printed by a 3D fused deposition modelling (FDM) printer with acrylonitrile butadiene styrene (ABS) as print material. The kinematics model of the soft parallel actuator is derived via transformation matrices notations to simulate and determine the workspace of the actuator. The printed soft parallel actuator is then immersed into NaOH solution with specific voltage applied to it via two contactless electrodes. The experimental data is then collected and used to develop a parametric model to estimate the end-effector position and regulate kinematics model in response to specific input voltage over time. It is observed that the electroactive actuator demonstrates expected behaviour according to the simulation of its kinematics model. The use of 3D printing for the fabrication of parallel soft actuators opens a new chapter in manufacturing sophisticated soft actuators with high dexterity and mechanical robustness for biomedical applications such as cell manipulation and drug release.

Novel arabinan and galactan oligosaccharides from dicotyledonous plants

NASA Astrophysics Data System (ADS)

Wefers, Daniel; Tyl, Catrin; Bunzel, Mirko

2014-11-01

Arabinans and galactans are neutral pectic side chains and an important part of the cell walls of dicotyledonous plants. To get a detailed insight into their fine structure, various oligosaccharides were isolated from quinoa, potato galactan, and sugar beet pulp after enzymatic treatment. LC-MS2 and one- and two-dimensional NMR spectroscopy were used for unambiguous structural characterization. It was demonstrated that arabinans contain β-(1→3)-linked arabinobiose as a side chain in quinoa seeds, while potato galactan was comprised of β-(1→4)-linked galactopyranoses which are interspersed with α-(1→4)-linked arabinopyranoses. Additionally, an oligosaccharide with two adjacent arabinofuranose units O2-substituted with two ferulic acid monomers was characterized. The isolated oligosaccharides gave further insight into the structures of pectic side chains and may have an impact on plant physiology and dietary fiber fermentation.

Spacer conformation in biologically active molecules. Part 2. Structure and conformation of 4-[2-(diphenylmethylamino)ethyl]-1-(2-methoxyphenyl) piperazine and its diphenylmethoxy analog—potential 5-HT 1A receptor ligands

NASA Astrophysics Data System (ADS)

Karolak-Wojciechowska, J.; Fruziński, A.; Czylkowski, R.; Paluchowska, M. H.; Mokrosz, M. J.

2003-09-01

As a part of studies on biologically active molecule structures with aliphatic linking chain, the structures of 4-[2-diphenylmethylamino)ethyl]-1-(2-methoxyphenyl)piperazine dihydrochloride ( 1) and 4-[2-diphenylmethoxy)ethyl]-1-(2-methoxyphenyl)piperazine fumarate ( 2) have been reported. In both compounds, four atomic non-all-carbons linking chains (N)C-C-X-C are present. The conformation of that linking spacer depends on the nature of the X-atom. The preferred conformation for chain with XNH has been found to be fully extended while for that with XO—the bend one. It was confirmed by conformational calculations (strain energy distribution and random search) and crystallographic data, including statistics from CCDC.

Physicochemical characterization and antitumour activity of exopolysaccharides produced by Lactobacillus casei SB27 from yak milk.

PubMed

Di, Wei; Zhang, Lanwei; Wang, Shumei; Yi, Huaxi; Han, Xue; Fan, Rongbo; Zhang, Yingchun

2017-09-01

Two high molecular weight fractions (LW1 and LW2) of exopolysaccharides (EPSs) produced by Lactobacillus casei SB27 were isolated from yak milk obtained from the Gansu Tibetan area of China. GC-MS, FTIR spectroscopy, methylation analysis and FE-SEM analysis were performed to elucidate the physicochemical characterization of these two fractions, and their in vitro antitumour activities were also evaluated. The molecular weights (Mws) of LW1 and LW2 as determined by HPGPC were 25.10 and 12.34kDa, respectively. Monosaccharide composition analysis revealed that LW1 and LW2 were mainly composed of galactose (52.4% and 57.4%, mol%) and glucose (29.1% and 22.2%, mol%), respectively. Methylation results showed that the main chain of LW1 likely involves (1→4)-linked Galp and (1→4)-linked Glcp with its side chains being (1→4,6)-linked Galp through the O-6 position connected to the backbone, whereas the main chain of LW2 likely involves (1→4)-linked Galp and (1→4)-linked Glcp with its side chains being (1→3)-Galp through the O-6 position of (1→3,6)-Galp linked to the main chain. Evaluation of the microcosmic morphology, as revealed by FE-SEM analysis of the two EPS fractions, showed a sheet-like appearance with a folded surface and a compact structure. The results from in vitro antitumour tests indicated that both LW1 and LW2 could significantly inhibit the proliferation of HT-29 colorectal cancer cells and up-regulated the expressions of Bad, Bax, Caspase-3 and -8 genes. Finally, TEM images revealed the apoptotic morphological changes of HT-29 cells induced by LW1 and LW2. Our results suggested that LW1 and LW2 possess potential not only for use in functional food products but also as a source of natural antitumour drugs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Production and characterization of a single-chain variable fragment linked alkaline phosphatase fusion protein for detection of O,O-diethyl organophosphorus pesticides in a one-step enzyme-linked immunosorbent assay

USDA-ARS?s Scientific Manuscript database

A single-chain variable fragment (scFv) and alkaline phosphatase (AP) fusion protein for detection of O, O-diethyl organophosphorus pesticides (OPs) was produced and characterized. The scFv gene was prepared by cloning VL and VH genes from a hybridoma cell secreting monoclonal antibody with broad-s...

Dynamics of quality as a strategic variable in complex food supply chain network competition: The case of fresh produce

NASA Astrophysics Data System (ADS)

Nagurney, Anna; Besik, Deniz; Yu, Min

2018-04-01

In this paper, we construct a competitive food supply chain network model in which the profit-maximizing producers decide not only as to the volume of fresh produce produced and distributed using various supply chain network pathways, but they also decide, with the associated costs, on the initial quality of the fresh produce. Consumers, in turn, respond to the various producers' product outputs through the prices that they are willing to pay, given also the average quality associated with each producer or brand at the retail outlets. The quality of the fresh produce is captured through explicit formulae that incorporate time, temperature, and other link characteristics with links associated with processing, shipment, storage, etc. Capacities on links are also incorporated as well as upper bounds on the initial product quality of the firms at their production/harvesting sites. The governing concept of the competitive supply chain network model is that of Nash Equilibrium, for which alternative variational inequality formulations are derived, along with existence results. An algorithmic procedure, which can be interpreted as a discrete-time tatonnement process, is then described and applied to compute the equilibrium produce flow patterns and accompanying link Lagrange multipliers in a realistic case study, focusing on peaches, which includes disruptions.

Kinetic chain abnormalities in the athletic shoulder.

PubMed

Sciascia, Aaron; Thigpen, Charles; Namdari, Surena; Baldwin, Keith

2012-03-01

Overhead activities require the shoulder to be exposed to and sustain repetitive loads. The segmental activation of the body's links, known as the kinetic chain, allows this to occur effectively. Proper muscle activation is achieved through generation of energy from the central segment or core, which then transfers the energy to the terminal links of the shoulder, elbow, and hand. The kinetic chain is best characterized by 3 components: optimized anatomy, reproducible efficient motor patterns, and the sequential generation of forces. However, tissue injury and anatomic deficits such as weakness and/or tightness in the leg, pelvic core, or scapular musculature can lead to overuse shoulder injuries. These injuries can be prevented and maladaptations can be detected with a thorough understanding of biomechanics of the kinetic chain as it relates to overhead activity.

Aluminum-induced dreierketten chain cross-links increase the mechanical properties of nanocrystalline calcium aluminosilicate hydrate

DOE PAGES

Geng, Guoqing; Myers, Rupert J.; Li, Jiaqi; ...

2017-03-10

The incorporation of Al and increased curing temperature promotes the crystallization and cross-linking of calcium (alumino)silicate hydrate (C-(A-)S-H), which is the primary binding phase in most contemporary concrete materials. However, the influence of Al-induced structural changes on the mechanical properties at atomistic scale is not well understood. Herein, synchrotron radiation-based high-pressure X-ray diffraction is used to quantify the influence of dreierketten chain cross-linking on the anisotropic mechanical behavior of C-(A-)S-H. We show that the ab-planar stiffness is independent of dreierketten chain defects, e.g. vacancies in bridging tetrahedra sites and Al for Si substitution. The c-axis of non-cross-linked C-(A-)S-H is moremore » deformable due to the softer interlayer opening but stiffens with decreased spacing and/or increased zeolitic water and Ca 2+ of the interlayer. Dreierketten chain cross-links act as ‘columns’ to resist compression, thus increasing the bulk modulus of C-(A-)S-H. We provide the first experimental evidence on the influence of the Al-induced atomistic configurational change on the mechanical properties of C-(A-)S-H. Our work advances the fundamental knowledge of C-(A-)S-H on the lowest level of its hierarchical structure, and thus can impact the way that innovative C-(A-)S-H-based cementitious materials are developed using a ‘bottom-up’ approach.« less

Aluminum-induced dreierketten chain cross-links increase the mechanical properties of nanocrystalline calcium aluminosilicate hydrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Geng, Guoqing; Myers, Rupert J.; Li, Jiaqi

The incorporation of Al and increased curing temperature promotes the crystallization and cross-linking of calcium (alumino)silicate hydrate (C-(A-)S-H), which is the primary binding phase in most contemporary concrete materials. However, the influence of Al-induced structural changes on the mechanical properties at atomistic scale is not well understood. Herein, synchrotron radiation-based high-pressure X-ray diffraction is used to quantify the influence of dreierketten chain cross-linking on the anisotropic mechanical behavior of C-(A-)S-H. We show that the ab-planar stiffness is independent of dreierketten chain defects, e.g. vacancies in bridging tetrahedra sites and Al for Si substitution. The c-axis of non-cross-linked C-(A-)S-H is moremore » deformable due to the softer interlayer opening but stiffens with decreased spacing and/or increased zeolitic water and Ca 2+ of the interlayer. Dreierketten chain cross-links act as ‘columns’ to resist compression, thus increasing the bulk modulus of C-(A-)S-H. We provide the first experimental evidence on the influence of the Al-induced atomistic configurational change on the mechanical properties of C-(A-)S-H. Our work advances the fundamental knowledge of C-(A-)S-H on the lowest level of its hierarchical structure, and thus can impact the way that innovative C-(A-)S-H-based cementitious materials are developed using a ‘bottom-up’ approach.« less

Simultaneous inhibition of multiple steps in the processing of N-linked oligosaccharides does not impair immunoglobulin secretion from rat hybridoma cells.

PubMed Central

Hashim, O H; Cushley, W

1988-01-01

The effects of inhibiting selected pairs of oligosaccharide-processing activities upon the secretion of IgM and IgG molecules have been investigated. In the presence of castanospermine (CSP) plus swainsonine (SW) or deoxynojirimycin (dNM) plus deoxymannojirimycin (dMM), secretion of IgM and IgG from rat hybridoma cells was unimpaired relative to control cultures. The structures of the N-linked oligosaccharides found on the Ig heavy chains isolated from treated cells or culture supernatants were shown to be qualitatively different from those associated with control Ig by persistent sensitivity to digestion by endo H. Furthermore, the electrophoretic mobilities of mu and gamma chains on SDS-PAGE derived from treated cells were consistently slower than those of control heavy chains. IgM and IgG were also efficiently secreted when all glucosidase and mannosidase activities were blocked, and the secreted heavy chains bore endo H-sensitive oligosaccharides. The data suggest that Ig secretion from hybridomas can proceed in the absence of N-linked oligosaccharide processing. Images Figure 1 Figure 2 Figure 3 PMID:3350578

Ubiquitin Lysine 63 Chain–Forming Ligases Regulate Apical Dominance in Arabidopsis[W][OA

PubMed Central

Yin, Xiao-Jun; Volk, Sara; Ljung, Karin; Mehlmer, Norbert; Dolezal, Karel; Ditengou, Franck; Hanano, Shigeru; Davis, Seth J.; Schmelzer, Elmon; Sandberg, Göran; Teige, Markus; Palme, Klaus; Pickart, Cecile; Bachmair, Andreas

2007-01-01

Lys-63–linked multiubiquitin chains play important roles in signal transduction in yeast and in mammals, but the functions for this type of chain in plants remain to be defined. The RING domain protein RGLG2 (for RING domain Ligase2) from Arabidopsis thaliana can be N-terminally myristoylated and localizes to the plasma membrane. It can form Lys-63–linked multiubiquitin chains in an in vitro reaction. RGLG2 has overlapping functions with its closest sequelog, RGLG1, and single mutants in either gene are inconspicuous. rglg1 rglg2 double mutant plants exhibit loss of apical dominance and altered phyllotaxy, two traits critically influenced by the plant hormone auxin. Auxin and cytokinin levels are changed, and the plants show a decreased response to exogenously added auxin. Changes in the abundance of PIN family auxin transport proteins and synthetic lethality with a mutation in the auxin transport regulator BIG suggest that the directional flow of auxin is modulated by RGLG activity. Modification of proteins by Lys-63–linked multiubiquitin chains is thus important for hormone-regulated, basic plant architecture. PMID:17586653

Modelling voltage sag mitigation using dynamic voltage restorer and analyzing power quality issue

NASA Astrophysics Data System (ADS)

Ismail, Nor Laili; Hidzir, Hizrin Dayana Mohd; Thanakodi, Suresh; Nazar, Nazatul Shiema Moh; Ibrahim, Pungut; Ali, Che Ku Muhammad Sabri Che Ku

2018-02-01

Power quality problem which are arise due to a fault or a pulsed load can have caused an interruption of critical load. The modern power systems are becoming more sensitive to the quality of the power supplied by the utility company. Voltage sags and swells, flicker, interruptions, harmonic distortion and other distortion to the sinusoidal waveform are the examples of the power quality problems. The most affected due to these problems is industrial customers who use a lot of sensitive equipment. There has suffered a huge loss to these problems. Resulting of broken or damage equipment if voltage sag exceeds the sensitive threshold of the equipment. Thus, device such as Static Synchronous Compensator (STATCOM) and Dynamic Voltage Restorer (DVR) has been created to solve this problem among users. DVR is a custom power device that most effective and efficient. This paper intended to report the DVR operations during voltage sag compensation.

Statistical model of a flexible inextensible polymer chain: The effect of kinetic energy.

PubMed

Pergamenshchik, V M; Vozniak, A B

2017-01-01

Because of the holonomic constraints, the kinetic energy contribution in the partition function of an inextensible polymer chain is difficult to find, and it has been systematically ignored. We present the first thermodynamic calculation incorporating the kinetic energy of an inextensible polymer chain with the bending energy. To explore the effect of the translation-rotation degrees of freedom, we propose and solve a statistical model of a fully flexible chain of N+1 linked beads which, in the limit of smooth bending, is equivalent to the well-known wormlike chain model. The partition function with the kinetic and bending energies and correlations between orientations of any pair of links and velocities of any pair of beads are found. This solution is precise in the limits of small and large rigidity-to-temperature ratio b/T. The last exact solution is essential as even very "harmless" approximation results in loss of the important effects when the chain is very rigid. For very high b/T, the orientations of different links become fully correlated. Nevertheless, the chain does not go over into a hard rod even in the limit b/T→∞: While the velocity correlation length diverges, the correlations themselves remain weak and tend to the value ∝T/(N+1). The N dependence of the partition function is essentially determined by the kinetic energy contribution. We demonstrate that to obtain the correct energy and entropy in a constrained system, the T derivative of the partition function has to be applied before integration over the constraint-setting variable.

Statistical model of a flexible inextensible polymer chain: The effect of kinetic energy

NASA Astrophysics Data System (ADS)

Pergamenshchik, V. M.; Vozniak, A. B.

2017-01-01

Because of the holonomic constraints, the kinetic energy contribution in the partition function of an inextensible polymer chain is difficult to find, and it has been systematically ignored. We present the first thermodynamic calculation incorporating the kinetic energy of an inextensible polymer chain with the bending energy. To explore the effect of the translation-rotation degrees of freedom, we propose and solve a statistical model of a fully flexible chain of N +1 linked beads which, in the limit of smooth bending, is equivalent to the well-known wormlike chain model. The partition function with the kinetic and bending energies and correlations between orientations of any pair of links and velocities of any pair of beads are found. This solution is precise in the limits of small and large rigidity-to-temperature ratio b /T . The last exact solution is essential as even very "harmless" approximation results in loss of the important effects when the chain is very rigid. For very high b /T , the orientations of different links become fully correlated. Nevertheless, the chain does not go over into a hard rod even in the limit b /T →∞ : While the velocity correlation length diverges, the correlations themselves remain weak and tend to the value ∝T /(N +1 ). The N dependence of the partition function is essentially determined by the kinetic energy contribution. We demonstrate that to obtain the correct energy and entropy in a constrained system, the T derivative of the partition function has to be applied before integration over the constraint-setting variable.

Slide-Ring Materials Using Cyclodextrin.

PubMed

Ito, Kohzo

2017-01-01

We have recently synthesized slide-ring materials using cyclodextrin by cross-linking polyrotaxanes, a typical supramolecule. The slide-ring materials have polymer chains with bulky end groups topologically interlocked by figure-of-eight shaped junctions. This indicates that the cross-links can pass through the polymer chains similar to pulleys to relax the tension of the backbone polymer chains. The slide-ring materials also differ from conventional polymers in that the entropy of rings affects the elasticity. As a result, the slide-ring materials show quite small Young's modulus not proportional to the cross-linking density. This concept can be applied to a wide variety of polymeric materials as well as gels. In particular, the slide-ring materials show remarkable scratch-proof properties for coating materials for automobiles, cell phones, mobile computers, and so on. Further current applications include vibration-proof insulation materials for sound speakers, highly abrasive polishing media, dielectric actuators, and so on.

Structure, chain conformation and antitumor activity of a novel polysaccharide from Lentinus edodes.

PubMed

Yu, Zhang; Ming, Gu; Kaiping, Wang; Zhixiang, Chen; Liquan, Dai; Jingyu, Liu; Fang, Zeng

2010-12-01

A water-soluble polysaccharide LT1 was isolated from the basidiocarps of Lentinus edodes by hot water extraction and ethanol precipitations, further purified by gel chromatography. The Mw of LT1 was estimated to be 642 kDa by using HPGPC. Chemical and spectroscopic studies illustrated that LT1 has a backbone chain composed of 1 → 4-linked and 1 → 3-linked glucopyranosyl residues and has branches of single glucosyl stubs at C-6 of β-(1 → 4)-linked glucopyranosyl. AFM and Congo-red test revealed that LT1 existed as triple helix chain in 0.10 M NaOH solution or distilled water. Our studies showed that LT1 presented significant antitumor bioactivities on Sarcoma180 solid tumor cell implanted in BALB/c mice, which implies that LT1 could be potentially applied as a natural antitumor drug. Copyright © 2010 Elsevier B.V. All rights reserved.

Fibrin chain cross-linking, fibrinolysis, and in vivo sealing efficacy of differently structured fibrin sealants.

PubMed

Hedrich, Hans Christian; Simunek, Manuela; Reisinger, Sonja; Ferguson, James; Gulle, Heinz; Goppelt, Andreas; Redl, Heinz

2012-08-01

In this study, we compared the sealing characteristics and efficacy of a fibrin sealant with reduced plasminogen (FS-rplg) and a fibrin sealant with aprotinin as a fibrinolysis inhibitor (FS-apr). The relevant sealing characteristics including clot structure, fibrin chain cross-linking, and clot lysis were tested in the laboratory. The sealing efficacy was then investigated in a follow-up animal model to determine differences in the in vivo sealing properties. A total of 46 animals were available for the final analysis with 23 animals in each treatment arm. In conclusion, we saw differences in vitro between FS-rplg and FS-apr in ultrastructure and α-chain cross-linking rates as well as in the rate of fibrinolysis. These differences may explain the significantly enhanced sealing efficacy in FS-apr compared to FS-rplg shown in vivo in a rabbit intestinal model. Copyright © 2012 Wiley Periodicals, Inc.

Biosynthesis of small proteoglycan II (decorin) by chondrocytes and evidence for a procore protein.

PubMed

Sawhney, R S; Hering, T M; Sandell, L J

1991-05-15

We have studied the biosynthesis of cartilage dermatan sulfate proteoglycan II (DS-PGII) (decorin) using in vitro translation of mRNA to determine the size of the primary gene product and by radiolabeling the protein in the presence of tunicamycin to inhibit the addition of Asn-linked oligosaccharides. Pulse-chase experiments were performed to examine post-translational processing and secretion. Inhibitors of oligosaccharide processing were used to determine whether DS-PGII molecules containing partially processed oligosaccharides could become proteoglycans and be secreted. Cell-free translation of sucrose gradient-fractionated RNA and subsequent immunoprecipitation of the core protein confirmed that the functional translated mRNA is in the size range of the two mRNA species observed by hybridization of chondrocyte RNA with a bone PGII cloned probe and that the translation product is a single protein with an apparent molecular mass of 42 kDa. Digestion of the intact proteoglycan (average molecular mass = 103 kDa) with chondroitinase ABC or AC results in an approximately 48-49-kDa product. Chondrocytes treated with tunicamycin to inhibit Asn-linked oligosaccharide addition synthesize and secrete a glycosaminoglycan (GAG)-substituted proteoglycan (average molecular mass = 86 kDa), yielding a 42-kDa core protein after chondroitinase ABC digestion, showing that Asn-linked oligosaccharides are not required for the addition of GAG chains or secretion. Following a short pulse (10 min) of [3H]leucine, three glycosylated forms of the DS-PGII core protein were observed, one of which is likely to be the precursor form of PGII predicted by the implied protein sequence of both bovine and human cDNA clones. Following the apparent cleavage of the propeptide, GAG-substituted intracellular core protein is detectable. Susceptibility to endoglycosidase H indicates that approximately one-third of the secreted core protein contains exclusively complex-type Asn-linked oligosaccharides and approximately two-thirds contain high mannose as well as complex-type oligosaccharides. Secreted DS-PGII appears to be fully substituted with three Asn-linked oligosaccharide chains. Inhibitors of oligosaccharide processing, however, permitted secretion of GAG-substituted DS-PGII that was fully (three chains) or incompletely (one or two chains) substituted with partially processed Asn-linked carbohydrate chains. By comparison of chondrocyte DS-PGII with fibroblast DS-PGII, we conclude that the addition and processing of Asn-linked carbohydrate chains are directed by the amino acid sequence of the core protein. The results reported here also suggest that the addition of xylose, the initial step in GAG chain synthesis, occurs early in biosynthesis and is determined by the primary amino acid sequence of the core protein.(ABSTRACT TRUNCATED AT 400 WORDS)

29 CFR 1918.52 - Specific requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... to join sections of, preventer guys. (b) Stoppers. (1) Chain topping lift stoppers shall be in good... chain. (2) Chain stoppers shall be shackled or otherwise secured so that their links are not bent by... control lever is pulled back and lowers when the lever is pushed forward. (d) Heel blocks. (1) When an...

29 CFR 1918.52 - Specific requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... to join sections of, preventer guys. (b) Stoppers. (1) Chain topping lift stoppers shall be in good... chain. (2) Chain stoppers shall be shackled or otherwise secured so that their links are not bent by... control lever is pulled back and lowers when the lever is pushed forward. (d) Heel blocks. (1) When an...

29 CFR 1918.52 - Specific requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... to join sections of, preventer guys. (b) Stoppers. (1) Chain topping lift stoppers shall be in good... chain. (2) Chain stoppers shall be shackled or otherwise secured so that their links are not bent by... control lever is pulled back and lowers when the lever is pushed forward. (d) Heel blocks. (1) When an...

29 CFR 1918.52 - Specific requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... to join sections of, preventer guys. (b) Stoppers. (1) Chain topping lift stoppers shall be in good... chain. (2) Chain stoppers shall be shackled or otherwise secured so that their links are not bent by... control lever is pulled back and lowers when the lever is pushed forward. (d) Heel blocks. (1) When an...

29 CFR 1918.52 - Specific requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... to join sections of, preventer guys. (b) Stoppers. (1) Chain topping lift stoppers shall be in good... chain. (2) Chain stoppers shall be shackled or otherwise secured so that their links are not bent by... control lever is pulled back and lowers when the lever is pushed forward. (d) Heel blocks. (1) When an...

Alport Syndrome Diagnosis

MedlinePlus

... the presence or absence of the type IV collagen alpha-3, alpha-4 and alpha-5 chains ( ... linked Alport syndrome) is suspected. The type IV collagen alpha-5 chain (COL4A5) is normally present in ...

Genetics Home Reference: short-chain acyl-CoA dehydrogenase deficiency

MedlinePlus

... Orphanet: Short chain acyl-CoA dehydrogenase deficiency Screening, Technology and Research in Genetics Patient Support and Advocacy Resources (5 links) Children Living with Inherited Metabolic Disease (CLIMB) Children's Mitochondrial ...

Failure Investigation of a Cage Suspension Gear Chain used in Coal Mines

NASA Astrophysics Data System (ADS)

Ghosh, Debashis; Dutta, Shamik; Shukla, Awdhesh Kumar; Roy, Himadri

2016-10-01

This investigation is primarily aimed to examine the probable causes of in-service failure of cage suspension gear chain used in coal mines. Preliminary visual examination, dimensional measurement, chemical analysis, magnetic particle inspection and estimation of mechanical properties are necessary supplement to this investigation. Optical microscopic analysis along with scanning electron microscopy examinations are carried out to understand the metallurgical reasons for failure. The visual examination and magnetic particle investigations reveal presence of fissure cracks at weld joint for both un-failed and failed end link chain. The average hardness value has been found to increase gradually with the distance from the weld interface. The macro and microstructural examinations of the samples prepared from both failed and un-failed specimens depict presence of continuous as well as aligned linear inclusions randomly distributed along with decarburized layer at weld interface/fusion zone. Fractographic examination shows flat fracture covering major portion of cross-section, which is surrounded by a narrow annular metallic fracture surface having a texture different from that of the remaining surface. Fracture mechanics principles have been used to study the fatigue crack growth rate in both weld region and base region of the un-failed gear chain material. Detailed stress analyses are also carried out to evaluate the stress generated along the chain periphery. Finally, it is concluded that presence of serious weld defect due to use of improper welding parameters/procedure caused failure of the end links of the investigated chain link.

Spark Plasma Sintering for Nanostructured Smart Materials

DTIC Science & Technology

2009-03-02

polyester) with excess isocyanate to form a prepolymer , followed by the addition of a short chain diol that acts as a chain extender to link the... prepolymers together. Due to the thermodynamic imicisibility of segments of PU, phase separation into a flexible soft segment (long chain diol) and a...other reactions of the isocyanate groups with the other functional groups in the chain. [Hepburn, 1992] However, during the initial prepolymer

Simulating the dynamic behavior of chain drive systems by advanced CAE programs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, J.; Meyer, J.

1996-09-01

Due to the increased requirements for chain drive systems of 4-stroke internal combustion engines CAE-tools are necessary to design the optimum dynamic system. In comparison to models used din the past the advantage of the new model CDD (Chain Drive Dynamics) is the capability of simulating the trajectory of each chain link around the drive system. Each chain link is represented by a mass with two degrees of freedom and is coupled to the next by a spring-damper element. The drive sprocket can be moved with a constant or non-constant speed. As in reality the other sprockets are driven bymore » the running chain and can be excited by torques. Due to these unique model features it is possible to calculate all vibration types of the chain, polygon effects and radial or angular vibrations of the sprockets very accurately. The model includes the detailed simulation of a mechanical or a hydraulic tensioner as well. The method is ready to be coupled to other detailed calculation models (e.g. valve train systems, crankshaft, etc.). The high efficiency of the tool predicting the dynamic and acoustic behavior of a chain drive system will be demonstrated in comparison to measurements.« less

Active Site Gate Dynamics Modulate the Catalytic Activity of the Ubiquitination Enzyme E2-25K.

PubMed

Rout, Manoj K; Lee, Brian L; Lin, Aiyang; Xiao, Wei; Spyracopoulos, Leo

2018-05-03

The ubiquitin proteasome system (UPS) signals for degradation of proteins through attachment of K48-linked polyubiquitin chains, or alterations in protein-protein recognition through attachment of K63-linked chains. Target proteins are ubiquitinated in three sequential chemical steps by a three-component enzyme system. Ubiquitination, or E2 enzymes, catalyze the central step by facilitating reaction of a target protein lysine with the C-terminus of Ub that is attached to the active site cysteine of the E2 through a thioester bond. E2 reactivity is modulated by dynamics of an active site gate, whose central residue packs against the active site cysteine in a closed conformation. Interestingly, for the E2 Ubc13, which specifically catalyzes K63-linked ubiquitination, the central gate residue adopts an open conformation. We set out to determine if active site gate dynamics play a role in catalysis for E2-25K, which adopts the canonical, closed gate conformation, and which selectively synthesizes K48-linked ubiquitin chains. Gate dynamics were characterized using mutagenesis of key residues, combined with enzyme kinetics measurements, and main chain NMR relaxation. The experimental data were interpreted with all atom MD simulations. The data indicate that active site gate opening and closing rates for E2-25K are precisely balanced.

Characterization of N-linked oligosaccharides assembled on secretory recombinant glucose oxidase and cell wall mannoproteins from the methylotrophic yeast Hansenula polymorpha.

PubMed

Kim, Moo Woong; Rhee, Sang Ki; Kim, Jeong-Yoon; Shimma, Yoh-ichi; Chiba, Yasunori; Jigami, Yoshifumi; Kang, Hyun Ah

2004-03-01

Presently almost no information is available on the oligosaccharide structure of the glycoproteins secreted from the methylotrophic yeast Hansenula polymorpha, a promising host for the production of recombinant proteins. In this study, we analyze the size distribution and structure of N-linked oligosaccharides attached to the recombinant glycoprotein glucose oxidase (GOD) and the cell wall mannoproteins obtained from H. polymorpha. Oligosaccharide profiling showed that the major oligosaccharide species derived from the H. polymorpha-secreted recombinant GOD (rGOD) had core-type structures (Man(8-12)GlcNAc(2)). Analyses using anti-alpha 1,3-mannose antibody and exoglycosidases specific for alpha 1,2- or alpha 1,6-mannose linkages revealed that the mannose outer chains of N-glycans on the rGOD have very short alpha 1,6 extensions and are mainly elongated in alpha 1,2-linkages without a terminal alpha 1,3-linked mannose addition. The N-glycans released from the H. polymorpha mannoproteins were shown to contain mostly mannose in their outer chains, which displayed almost identical size distribution and structure to those of H. polymorpha-derived rGOD. These results strongly indicate that the outer chain processing of N-glycans by H. polymorpha significantly differs from that by Saccharomyces cerevisiae, thus generating much shorter mannose outer chains devoid of terminal alpha 1,3-linked mannoses.

[Detection of large deletions in X linked Alport syndrome using competitive multiplex fluorescence polymerase chain reaction].

PubMed

Wang, F; Zhang, Y Q; Ding, J; Yu, L X

2017-10-18

To evaluate the ability of multiplex competitive fluorescence polymerase chain reaction in detection of large deletion and duplication genotypes of X-linked Alport syndrome. Clinical diagnosis of X-linked Alport syndrome was based on either abnormal staining of type IV collagen α5 chain in the epidermal basement membrane alone or with abnormal staining of type IV collagen α5 chain in the glomerular basement membrane and Bowman's capsule/ultrastructural changes in the glomerular basement membrane typical of Alport syndrome. A total of 20 unrelated Chinese patients (13 males and 7 females) clinically diagnosed as X-linked Alport syndrome were included in the study. Their genotypes were unknown. Control subjects included a male patient with other renal disease and two patients who had large deletions in COL4A5 gene detected by multiplex ligation-dependent probe amplification. Genomic DNA was isolated from peripheral blood leukocytes in all the participants. Multiplex competitive fluorescence polymerase chain reaction was used to coamplify 53 exons of COL4A5 gene and four reference genes in a single reaction. When a deletion removed exon 1 of COL4A5 gene was identified, the same method was used to coamplify the first 4 exons of COL4A5 and COL4A6 genes, a promoter shared by COL4A5 and COL4A6 genes, and three reference genes in a single reaction. Any copy number loss suggested by this method was verified by electrophoresis of corresponding polymerase chain reaction amplified products or DNA sequencing to exclude possible DNA variations in the primer regions. Genotypes of two positive controls identified by multiplex competitive fluorescence polymerase chain reaction were consistent with those detected by multiplex ligation-dependent probe amplification. Deletions were identified in 6 of the 20 patients, including two large deletions removing the 5' part of both COL4A5 and COL4A6 genes with the breakpoint located in the second intron of COL4A6, two large deletions removing more than 30 exons of COL4A5 gene, one large deletion removing at least 1 exon of COL4A5 gene, and one small deletion involving 13 bps. No duplication was found. Our results show that multiplex competitive fluorescence polymerase chain reaction is a good alternative to classical techniques for large deletion genotyping in X-linked Alport syndrome.

The Non-catalytic B Subunit of Coagulation Factor XIII Accelerates Fibrin Cross-linking*

PubMed Central

Souri, Masayoshi; Osaki, Tsukasa; Ichinose, Akitada

2015-01-01

Covalent cross-linking of fibrin chains is required for stable blood clot formation, which is catalyzed by coagulation factor XIII (FXIII), a proenzyme of plasma transglutaminase consisting of catalytic A (FXIII-A) and non-catalytic B subunits (FXIII-B). Herein, we demonstrate that FXIII-B accelerates fibrin cross-linking. Depletion of FXIII-B from normal plasma supplemented with a physiological level of recombinant FXIII-A resulted in delayed fibrin cross-linking, reduced incorporation of FXIII-A into fibrin clots, and impaired activation peptide cleavage by thrombin; the addition of recombinant FXIII-B restored normal fibrin cross-linking, FXIII-A incorporation into fibrin clots, and activation peptide cleavage by thrombin. Immunoprecipitation with an anti-fibrinogen antibody revealed an interaction between the FXIII heterotetramer and fibrinogen mediated by FXIII-B and not FXIII-A. FXIII-B probably binds the γ-chain of fibrinogen with its D-domain, which is near the fibrin polymerization pockets, and dissociates from fibrin during or after cross-linking between γ-chains. Thus, FXIII-B plays important roles in the formation of a ternary complex between proenzyme FXIII, prosubstrate fibrinogen, and activator thrombin. Accordingly, congenital or acquired FXIII-B deficiency may result in increased bleeding tendency through impaired fibrin stabilization due to decreased FXIII-A activation by thrombin and secondary FXIII-A deficiency arising from enhanced circulatory clearance. PMID:25809477

Rapid Acquisition of Choice and Timing and the Provenance of the Terminal-Link Effect

ERIC Educational Resources Information Center

Kyonka, Elizabeth G. E.; Grace, Randolph C.

2010-01-01

Eight pigeons responded in a concurrent-chains procedure in which terminal-link schedules changed pseudorandomly across sessions. Pairs of terminal-link delays either summed to 15 s or to 45 s. Across sessions, the location of the shorter terminal link changed according to a pseudorandom binary sequence. On some terminal links, food was withheld…

The Formation Mechanism of Hydrogels.

PubMed

Lu, Liyan; Yuan, Shiliang; Wang, Jing; Shen, Yun; Deng, Shuwen; Xie, Luyang; Yang, Qixiang

2017-06-12

Hydrogels are degradable polymeric networks, in which cross-links play a vital role in structure formation and degradation. Cross-linking is a stabilization process in polymer chemistry that leads to the multi-dimensional extension of polymeric chains, resulting in network structures. By cross-linking, hydrogels are formed into stable structures that differ from their raw materials. Generally, hydrogels can be prepared from either synthetic or natural polymers. Based on the types of cross-link junctions, hydrogels can be categorized into two groups: the chemically cross-linked and the physically cross-linked. Chemically cross-linked gels have permanent junctions, in which covalent bonds are present between different polymer chains, thus leading to excellent mechanical strength. Although chemical cross-linking is a highly resourceful method for the formation of hydrogels, the cross-linkers used in hydrogel preparation should be extracted from the hydrogels before use, due to their reported toxicity, while, in physically cross-linked gels, dissolution is prevented by physical interactions, such as ionic interactions, hydrogen bonds or hydrophobic interactions. Physically cross-linked methods for the preparation of hydrogels are the alternate solution for cross-linker toxicity. Both methods will be discussed in this essay. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Knowing the SCOR: using business metrics to gain measurable improvements.

PubMed

Malin, Jane H

2006-07-01

By using the Supply Chain Operations Reference model, one New York hospital was able to define and measure its supply chains, determine the weak links in its processes, and identify necessary improvements.

MMDB: Entrez’s 3D-structure database

PubMed Central

Wang, Yanli; Anderson, John B.; Chen, Jie; Geer, Lewis Y.; He, Siqian; Hurwitz, David I.; Liebert, Cynthia A.; Madej, Thomas; Marchler, Gabriele H.; Marchler-Bauer, Aron; Panchenko, Anna R.; Shoemaker, Benjamin A.; Song, James S.; Thiessen, Paul A.; Yamashita, Roxanne A.; Bryant, Stephen H.

2002-01-01

Three-dimensional structures are now known within many protein families and it is quite likely, in searching a sequence database, that one will encounter a homolog with known structure. The goal of Entrez’s 3D-structure database is to make this information, and the functional annotation it can provide, easily accessible to molecular biologists. To this end Entrez’s search engine provides three powerful features. (i) Sequence and structure neighbors; one may select all sequences similar to one of interest, for example, and link to any known 3D structures. (ii) Links between databases; one may search by term matching in MEDLINE, for example, and link to 3D structures reported in these articles. (iii) Sequence and structure visualization; identifying a homolog with known structure, one may view molecular-graphic and alignment displays, to infer approximate 3D structure. In this article we focus on two features of Entrez’s Molecular Modeling Database (MMDB) not described previously: links from individual biopolymer chains within 3D structures to a systematic taxonomy of organisms represented in molecular databases, and links from individual chains (and compact 3D domains within them) to structure neighbors, other chains (and 3D domains) with similar 3D structure. MMDB may be accessed at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=Structure. PMID:11752307

Proteoglycans synthesized by smooth muscle cells derived from monkey (Macaca nemestrina) aorta.

PubMed

Chang, Y; Yanagishita, M; Hascall, V C; Wight, T N

1983-05-10

Smooth muscle cells derived from monkey aorta were cultured in medium with [35S]sulfate and [3H]glucosamine as labeling precursors. Proteoglycans in the medium and in 4 M guanidine HCl extracts of the cell layer were purified by DEAE-Sephacel and molecular sieve chromatography. Both preparations contained a predominant, large chondroitin sulfate proteoglycan (Kav = 0.30 on Sepharose CL-2B) with glycosaminoglycan chains of Mr approximately 43,000 average containing a ratio of 6-sulfate to 4-sulfate of approximately 2. Approximately 7 and 27% of the 3H label in this proteoglycan were present in N-linked and O-linked oligosaccharides, respectively. Reaggregation experiments indicated that a large proportion of these proteoglycans can form link protein-stabilized aggregates. The medium fraction also contained a smaller dermatan sulfate proteoglycan (Kav = 0.67 on Sepharose CL-2B) with glycosaminoglycan chains of Mr approximately 43,000 containing a ratio of 6-sulfate to 4-sulfate of about 0.5. This proteoglycan contained approximately the same percentage of N-linked oligosaccharides as the chondroitin sulfate proteoglycan, but few or no O-linked oligosaccharides. A smaller dermatan sulfate proteoglycan with a single chain was present only in the cell layer. Additionally, small amounts of heparan sulfate proteoglycans were synthesized by the cells.

Dual RING E3 Architectures Regulate Multiubiquitination and Ubiquitin Chain Elongation by APC/C.

PubMed

Brown, Nicholas G; VanderLinden, Ryan; Watson, Edmond R; Weissmann, Florian; Ordureau, Alban; Wu, Kuen-Phon; Zhang, Wei; Yu, Shanshan; Mercredi, Peter Y; Harrison, Joseph S; Davidson, Iain F; Qiao, Renping; Lu, Ying; Dube, Prakash; Brunner, Michael R; Grace, Christy R R; Miller, Darcie J; Haselbach, David; Jarvis, Marc A; Yamaguchi, Masaya; Yanishevski, David; Petzold, Georg; Sidhu, Sachdev S; Kuhlman, Brian; Kirschner, Marc W; Harper, J Wade; Peters, Jan-Michael; Stark, Holger; Schulman, Brenda A

2016-06-02

Protein ubiquitination involves E1, E2, and E3 trienzyme cascades. E2 and RING E3 enzymes often collaborate to first prime a substrate with a single ubiquitin (UB) and then achieve different forms of polyubiquitination: multiubiquitination of several sites and elongation of linkage-specific UB chains. Here, cryo-EM and biochemistry show that the human E3 anaphase-promoting complex/cyclosome (APC/C) and its two partner E2s, UBE2C (aka UBCH10) and UBE2S, adopt specialized catalytic architectures for these two distinct forms of polyubiquitination. The APC/C RING constrains UBE2C proximal to a substrate and simultaneously binds a substrate-linked UB to drive processive multiubiquitination. Alternatively, during UB chain elongation, the RING does not bind UBE2S but rather lures an evolving substrate-linked UB to UBE2S positioned through a cullin interaction to generate a Lys11-linked chain. Our findings define mechanisms of APC/C regulation, and establish principles by which specialized E3-E2-substrate-UB architectures control different forms of polyubiquitination. Copyright © 2016 Elsevier Inc. All rights reserved.

Polysaccharides from brown algae Sargassum duplicatum: the structure and anticancer activity in vitro.

PubMed

Usoltseva, Roza V; Anastyuk, Stanislav D; Shevchenko, Natalia M; Surits, Valerii V; Silchenko, Artem S; Isakov, Vladimir V; Zvyagintseva, Tatiana N; Thinh, Pham Duc; Ermakova, Svetlana P

2017-11-01

The laminaran SdL and fucoidan SdF were isolated from brown algae Sargassum duplicatum. SdL was 1,3;1,6-β-d-glucan (1,3:1,6=6:1) with a main chain, represented by 1,3-linked glucose residues, due to NMR spectroscopy data. Single glucose residues could form branches at C6. Unusual structure of fucoidan SdF was studied by chemical and enzymatic methods, NMR spectroscopy of desulfated and deacetylated polysaccharide and mass spectrometry of fucoidan fragments labeled with 18 O. Fucoidan was sulfated (31.7%) and acetylated galactofucan (Fuc:Gal∼1:1) with a main chain of 1,4-linked alternating α-l-fucose and β-d-galactose residues. Side chains were represented by extensive (DP≥5) 1,3-linked 2,4-disulfated α-l-fucose residues with branching points at C2. Fucose residues in the main chain were sulfated at C2 and less at C3, while galactose residues were sulfated at C2, C3, and less at C4, C6. The fucoidan SdF was effective against colony formation of colon cancer cells in vitro. Copyright © 2017 Elsevier Ltd. All rights reserved.

DFT Modeling of Cross-Linked Polyethylene: Role of Gold Atoms and Dispersion Interactions.

PubMed

Blaško, Martin; Mach, Pavel; Antušek, Andrej; Urban, Miroslav

2018-02-08

Using DFT modeling, we analyze the concerted action of gold atoms and dispersion interactions in cross-linked polyethylene. Our model consists of two oligomer chains (PEn) with 7, 11, 15, 19, or 23 carbon atoms in each oligomer cross-linked with one to three Au atoms through C-Au-C bonds. In structures with a single gold atom the C-Au-C bond is located in the central position of the oligomer. Binding energies (BEs) with respect to two oligomer radical fragments and Au are as high as 362-489 kJ/mol depending on the length of the oligomer chain. When the dispersion contribution in PEn-Au-PEn oligomers is omitted, BE is almost independent of the number of carbon atoms, lying between 293 and 296 kJ/mol. The dispersion energy contributions to BEs in PEn-Au-PEn rise nearly linearly with the number of carbon atoms in the PEn chain. The carbon-carbon distance in the C-Au-C moiety is around 4.1 Å, similar to the bond distance between saturated closed shell chains in the polyethylene crystal. BEs of pure saturated closed shell PEn-PEn oligomers are 51-187 kJ/mol. Both Au atoms and dispersion interactions contribute considerably to the creation of nearly parallel chains of oligomers with reasonably high binding energies.

The innovation value chain.

PubMed

Hansen, Morten T; Birkinshaw, Julian

2007-06-01

The challenges of coming up with fresh ideas and realizing profits from them are different for every company. One firm may excel at finding good ideas but may have weak systems for bringing them to market. Another organization may have a terrific process for funding and rolling out new products and services but a shortage of concepts to develop. In this article, Hansen and Birkinshaw caution executives against using the latest and greatest innovation approaches and tools without understanding the unique deficiencies in their companies' innovation systems. They offer a framework for evaluating innovation performance: the innovation value chain. It comprises the three main phases of innovation (idea generation, conversion, and diffusion) as well as the critical activities performed during those phases (looking for ideas inside your unit; looking for them in other units; looking for them externally; selecting ideas; funding them; and promoting and spreading ideas companywide). Using this framework, managers get an end-to-end view of their innovation efforts. They can pinpoint their weakest links and tailor innovation best practices appropriately to strengthen those links. Companies typically succumb to one of three broad "weakest-link" scenarios. They are idea poor, conversion poor, or diffusion poor. The article looks at the ways smart companies - including Intuit, P&G, Sara Lee, Shell, and Siemens- modify the best innovation practices and apply them to address those organizations' individual needs and flaws. The authors warn that adopting the chain-based view of innovation requires new measures of what can be delivered by each link in the chain. The approach also entails new roles for employees "external scouts" and "internal evangelists," for example. Indeed, in their search for new hires, companies should seek out those candidates who can help address particular weaknesses in the innovation value chain.

Secondary cell-wall assembly in flax phloem fibres: role of galactans.

PubMed

Gorshkova, Tatyana; Morvan, Claudine

2006-01-01

Non-lignified fibre cells (named gelatinous fibres) are present in tension wood and the stems of fibre crops (such as flax and hemp). These cells develop a very thick S2 layer within the secondary cell wall, which is characterised by (1) cellulose microfibrils largely parallel to the longitudinal axis of the cell, and (2) a high proportion of galactose-containing polymers among the non-cellulosic polysaccharides. In this review, we focus on the role of these polymers in the assembly of gelatinous fibres of flax. At the different stages of fibre development, we analyse in detail data based on sugar composition, linkages of pectic polymers, and immunolocalisation of the beta-(1-->4)-galactans. These data indicate that high molecular-mass gelatinous galactans accumulate in specialised Golgi-derived vesicles during fibre cell-wall thickening. They consist of RG-I-like polymers with side chains of beta-(1-->4)-linked galactose. Most of them are short, but there are also long chains containing up to 28 galactosyl residues. At fibre maturity, two types of cross-linked galactans are identified, a C-L structure that resembles the part of soluble galactan with long side chains and a C-S structure with short chains. Different possibilities for soluble galactan to give rise to C-L and C-S are analysed. In addition, we discuss the prospect for the soluble galactan in preventing the newly formed cellulose chains from completing immediate crystallisation. This leads to a hypothesis that firstly the secretion of soluble galactans plays a role in the axial orientation of cellulose microfibrils, and secondly the remodelling and cross-linking of pectic galactans are linked to the dehydration and the assembly of S2 layer.

Acquisition of choice in concurrent chains: Assessing the cumulative decision model.

PubMed

Grace, Randolph C

2016-05-01

Concurrent chains is widely used to study pigeons' choice between terminal links that can vary in delay, magnitude, or probability of reinforcement. We review research on the acquisition of choice in this procedure. Acquisition has been studied with a variety of research designs, and some studies have incorporated no-food trials to allow for timing and choice to be observed concurrently. Results show that: Choice can be acquired rapidly within sessions when terminal links change unpredictably; under steady-state conditions, acquisition depends on both initial- and terminal-link schedules; and initial-link responding is mediated by learning about the terminal-link stimulus-reinforcer relations. The cumulative decision model (CDM) proposed by Christensen and Grace (2010) and Grace and McLean (2006, 2015) provides a good description of within-session acquisition, and correctly predicts the effects of initial and terminal-link schedules in steady-state designs (Grace, 2002a). Questions for future research include how abrupt shifts in preference within individual sessions and temporal control of terminal-link responding can be modeled. Copyright © 2016 Elsevier B.V. All rights reserved.

Thermal conductivity of cross-linked polyethylene from molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Xiong, Xue; Yang, Ming; Liu, Changlin; Li, Xiaobo; Tang, Dawei

2017-07-01

The thermal conductivity of cross-linked bulk polyethylene is studied using molecular dynamics simulation. The atomic structure of the cross-linked polyethylene (PEX) is generated through simulated bond formation using LAMMPS. The thermal conductivity of PEX is studied with different degrees of crosslinking, chain length, and tensile strain. Generally, the thermal conductivity increases with the increasing degree of crosslinking. When the length of the primitive chain increases, the thermal conductivity increases linearly. When the polymer is stretched along one direction, the thermal conductivity increases in the stretched direction and decreases in the direction perpendicular to it. However, the thermal conductivity varies slightly when the polymer is stretched in three directions simultaneously.

5-Nitro-N 4,N 6-diphenyl­pyrimidine-4,6-diamine: polarized mol­ecules linked into π-stacked chains via three-centre C—H⋯(O)2 hydrogen bonds

PubMed Central

Rodríguez, Ricaurte; Nogueras, Manuel; Cobo, Justo; Glidewell, Christopher

2009-01-01

Mol­ecules of the title compound, C16H13N5O2, have no inter­nal symmetry despite the symmetric pattern of substitution in the pyrimidine ring. The intra­molecular distances indicate polarization of the electronic structure. There are two intra­molecular N—H⋯O hydrogen bonds and mol­ecules are linked into centrosymmetric dimers by pairs of three-centre C—H⋯(O)2 hydrogen bonds. These dimers are linked into chains by means of a π–π stacking inter­action. PMID:19726856

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Jongmin; Saba, Stacey A.; Hillmyer, Marc A.

We report on the phase separation behaviors of polymerization mixtures containing a polylactide macro-chain transfer agent (PLA-CTA), styrene, divinylbenzene, hydroxyl-terminated PLA (PLA-OH), and a molecular chain transfer agent which enable the ability to tune the pore size of a cross-linked polymer monolith in a facile manner. Cross-linked monoliths were produced from the mixtures via reversible addition-fragmentation chain transfer (RAFT) polymerization and converted into cross-linked porous polymers by selective removal of PLA while retaining the parent morphology. We demonstrate that pore sizes are tunable over a wide range of length scales from the meso- to macroporous regimes by adjusting the ratiomore » of PLA-CTA to PLA-OH in the reaction mixture which causes the phase separation mechanism to change from polymerization-induced microphase separation to polymerization-induced phase separation. The possibility of increasing porosity and inducing simultaneous micro- and macrophase separation was also realized by adjustments in the molar mass of PLA which enabled the synthesis of hierarchically meso- and macroporous polymers.« less

Thermoplastic tape compaction device

DOEpatents

Campbell, Vincent W.

1994-01-01

A device for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite.

Actin binding by Hip1 (huntingtin-interacting protein 1) and Hip1R (Hip1-related protein) is regulated by clathrin light chain.

PubMed

Wilbur, Jeremy D; Chen, Chih-Ying; Manalo, Venus; Hwang, Peter K; Fletterick, Robert J; Brodsky, Frances M

2008-11-21

The huntingtin-interacting protein family members (Hip1 and Hip1R in mammals and Sla2p in yeast) link clathrin-mediated membrane traffic to actin cytoskeleton dynamics. Genetic data in yeast have implicated the light chain subunit of clathrin in regulating this link. To test this hypothesis, the biophysical properties of mammalian Hip1 and Hip1R and their interaction with clathrin light chain and actin were analyzed. The coiled-coil domains (clathrin light chain-binding) of Hip1 and Hip1R were found to be stable homodimers with no propensity to heterodimerize in vitro. Homodimers were also predominant in vivo, accounting for cellular segregation of Hip1 and Hip1R functions. Coiled-coil domains of Hip1 and Hip1R differed in their stability and flexibility, correlating with slightly different affinities for clathrin light chain and more markedly with effects of clathrin light chain binding on Hip protein-actin interactions. Clathrin light chain binding induced a compact conformation of both Hip1 and Hip1R and significantly reduced actin binding by their THATCH domains. Thus, clathrin is a negative regulator of Hip-actin interactions. These observations necessarily change models proposed for Hip protein function.

Actin Binding by Hip1 (Huntingtin-interacting Protein 1) and Hip1R (Hip1-related Protein) Is Regulated by Clathrin Light Chain*S⃞

PubMed Central

Wilbur, Jeremy D.; Chen, Chih-Ying; Manalo, Venus; Hwang, Peter K.; Fletterick, Robert J.; Brodsky, Frances M.

2008-01-01

The huntingtin-interacting protein family members (Hip1 and Hip1R in mammals and Sla2p in yeast) link clathrin-mediated membrane traffic to actin cytoskeleton dynamics. Genetic data in yeast have implicated the light chain subunit of clathrin in regulating this link. To test this hypothesis, the biophysical properties of mammalian Hip1 and Hip1R and their interaction with clathrin light chain and actin were analyzed. The coiled-coil domains (clathrin light chain-binding) of Hip1 and Hip1R were found to be stable homodimers with no propensity to heterodimerize in vitro. Homodimers were also predominant in vivo, accounting for cellular segregation of Hip1 and Hip1R functions. Coiled-coil domains of Hip1 and Hip1R differed in their stability and flexibility, correlating with slightly different affinities for clathrin light chain and more markedly with effects of clathrin light chain binding on Hip protein-actin interactions. Clathrin light chain binding induced a compact conformation of both Hip1 and Hip1R and significantly reduced actin binding by their THATCH domains. Thus, clathrin is a negative regulator of Hip-actin interactions. These observations necessarily change models proposed for Hip protein function. PMID:18790740

Genetics Home Reference: very long-chain acyl-CoA dehydrogenase deficiency

MedlinePlus

... Very long chain acyl-CoA dehydrogenase deficiency Screening, Technology, and Research in Genetics Virginia Department of Health (PDF) Patient Support and Advocacy Resources (4 links) Children's Mitochondrial Disease Network (UK) FOD (Fatty Oxidation Disorders) ...

Genetics Home Reference: long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency

MedlinePlus

... Long chain 3-hydroxyacyl-CoA dehydrogenase deficiency Screening, Technology, and Research in Genetics Virginia Department of Health (PDF) Patient Support and Advocacy Resources (4 links) Children Living with Inherited Metabolic Diseases (CLIMB) Children's Mitochondrial ...

A 'periodic table' for protein structures.

PubMed

Taylor, William R

2002-04-11

Current structural genomics programs aim systematically to determine the structures of all proteins coded in both human and other genomes, providing a complete picture of the number and variety of protein structures that exist. In the past, estimates have been made on the basis of the incomplete sample of structures currently known. These estimates have varied greatly (between 1,000 and 10,000; see for example refs 1 and 2), partly because of limited sample size but also owing to the difficulties of distinguishing one structure from another. This distinction is usually topological, based on the fold of the protein; however, in strict topological terms (neglecting to consider intra-chain cross-links), protein chains are open strings and hence are all identical. To avoid this trivial result, topologies are determined by considering secondary links in the form of intra-chain hydrogen bonds (secondary structure) and tertiary links formed by the packing of secondary structures. However, small additions to or loss of structure can make large changes to these perceived topologies and such subjective solutions are neither robust nor amenable to automation. Here I formalize both secondary and tertiary links to allow the rigorous and automatic definition of protein topology.

Mapping PDB chains to UniProtKB entries.

PubMed

Martin, Andrew C R

2005-12-01

UniProtKB/SwissProt is the main resource for detailed annotations of protein sequences. This database provides a jumping-off point to many other resources through the links it provides. Among others, these include other primary databases, secondary databases, the Gene Ontology and OMIM. While a large number of links are provided to Protein Data Bank (PDB) files, obtaining a regularly updated mapping between UniProtKB entries and PDB entries at the chain or residue level is not straightforward. In particular, there is no regularly updated resource which allows a UniProtKB/SwissProt entry to be identified for a given residue of a PDB file. We have created a completely automatically maintained database which maps PDB residues to residues in UniProtKB/SwissProt and UniProtKB/trEMBL entries. The protocol uses links from PDB to UniProtKB, from UniProtKB to PDB and a brute-force sequence scan to resolve PDB chains for which no annotated link is available. Finally the sequences from PDB and UniProtKB are aligned to obtain a residue-level mapping. The resource may be queried interactively or downloaded from http://www.bioinf.org.uk/pdbsws/.

Drill drive mechanism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dressel, M.O.

1979-10-30

A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfacesmore » of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the different gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft. 11 claims.« less

Drill drive mechanism

DOEpatents

Dressel, Michael O.

1979-01-01

A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfaces of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the differential gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft.

Gold nanorod linking to control plasmonic properties in solution and polymer nanocomposites.

PubMed

Ferrier, Robert C; Lee, Hyun-Su; Hore, Michael J A; Caporizzo, Matthew; Eckmann, David M; Composto, Russell J

2014-02-25

A novel, solution-based method is presented to prepare bifunctional gold nanorods (B-NRs), assemble B-NRs end-to-end in various solvents, and disperse linked B-NRs in a polymer matrix. The B-NRs have poly(ethylene glycol) grafted along its long axis and cysteine adsorbed to its ends. By controlling cysteine coverage, bifunctional ligands or polymer can be end-grafted to the AuNRs. Here, two dithiol ligands (C6DT and C9DT) are used to link the B-NRs in organic solvents. With increasing incubation time, the nanorod chain length increases linearly as the longitudinal surface plasmon resonance shifts toward lower adsorption wavelengths (i.e., red shift). Analogous to step-growth polymerization, the polydispersity in chain length also increases. Upon adding poly(ethylene glycol) or poly(methyl methacrylate) to chloroform solution with linked B-NR, the nanorod chains are shown to retain end-to-end linking upon spin-casting into PEO or PMMA films. Using quartz crystal microbalance with dissipation (QCM-D), the mechanism of nanorod linking is investigated on planar gold surfaces. At submonolayer coverage of cysteine, C6DT molecules can insert between cysteines and reach an areal density of 3.4 molecules per nm(2). To mimic the linking of Au NRs, this planar surface is exposed to cysteine-coated Au nanoparticles, which graft at 7 NPs per μm(2). This solution-based method to prepare, assemble, and disperse Au nanorods is applicable to other nanorod systems (e.g., CdSe) and presents a new strategy to assemble anisotropic particles in organic solvents and polymer coatings.

Gold Nanorod Linking to Control Plasmonic Properties in Solution and Polymer Nanocomposites

PubMed Central

2015-01-01

A novel, solution-based method is presented to prepare bifunctional gold nanorods (B-NRs), assemble B-NRs end-to-end in various solvents, and disperse linked B-NRs in a polymer matrix. The B-NRs have poly(ethylene glycol) grafted along its long axis and cysteine adsorbed to its ends. By controlling cysteine coverage, bifunctional ligands or polymer can be end-grafted to the AuNRs. Here, two dithiol ligands (C6DT and C9DT) are used to link the B-NRs in organic solvents. With increasing incubation time, the nanorod chain length increases linearly as the longitudinal surface plasmon resonance shifts toward lower adsorption wavelengths (i.e., red shift). Analogous to step-growth polymerization, the polydispersity in chain length also increases. Upon adding poly(ethylene glycol) or poly(methyl methacrylate) to chloroform solution with linked B-NR, the nanorod chains are shown to retain end-to-end linking upon spin-casting into PEO or PMMA films. Using quartz crystal microbalance with dissipation (QCM-D), the mechanism of nanorod linking is investigated on planar gold surfaces. At submonolayer coverage of cysteine, C6DT molecules can insert between cysteines and reach an areal density of 3.4 molecules per nm2. To mimic the linking of Au NRs, this planar surface is exposed to cysteine-coated Au nanoparticles, which graft at 7 NPs per μm2. This solution-based method to prepare, assemble, and disperse Au nanorods is applicable to other nanorod systems (e.g., CdSe) and presents a new strategy to assemble anisotropic particles in organic solvents and polymer coatings. PMID:24483622

Crystal structures of 3,5-bis-[(E)-3-hy-droxy-benzyl-idene]-1-methyl-piperidin-4-one and 3,5-bis-[(E)-2-chloro-benzyl-idene]-1-methyl-piperidin-4-one.

PubMed

Eryanti, Yum; Zamri, Adel; Herlina, Tati; Supratman, Unang; Rosli, Mohd Mustaqim; Fun, Hoong-Kun

2015-12-01

The title compounds, C20H19NO3, (1), and C20H17Cl2NO, (2), are the 3-hy-droxy-benzyl-idene and 2-chloro-benzyl-idene derivatives, respectively, of curcumin [systematic name: (1E,6E)-1,7-bis-(4-hy-droxy-3-meth-oxy-phen-yl)-1,6-hepta-diene-3,5-dione]. The dihedral angles between the benzene rings in each compound are 21.07 (6)° for (1) and 13.4 (3)° for (2). In both compounds, the piperidinone rings adopt a sofa confirmation and the methyl group attached to the N atom is in an equatorial position. In the crystal of (1), two pairs of O-H⋯N and O-H⋯O hydrogen bonds link the mol-ecules, forming chains along [10-1]. The chains are linked via C-H⋯O hydrogen bonds, forming undulating sheets parallel to the ac plane. In the crystal of (2), mol-ecules are linked by weak C-H⋯Cl hydrogen bonds, forming chains along the [204] direction. The chains are linked along the a-axis direction by π-π inter-actions [inter-centroid distance = 3.779 (4) Å]. For compound (2), the crystal studied was a non-merohedral twin with the refined ratio of the twin components being 0.116 (6):0.886 (6).

Temporal context, preference, and resistance to change.

PubMed

Podlesnik, Christopher A; Jimenez-Gomez, Corina; Thrailkill, Eric A; Shahan, Timothy A

2011-09-01

According to behavioral momentum theory, preference and relative resistance to change in concurrent-chains schedules are correlated and reflect the relative conditioned value of discriminative stimuli. In the present study, we explore the generality of this relation by manipulating the temporal context within a concurrent-chains procedure through changes in the duration of the initial links. Consistent with previous findings, preference for a richer terminal link was less extreme with longer initial links across three experiments with pigeons. In Experiment 1, relative resistance to change and preference were related inversely when responding was disrupted with response-independent food presentations during initial links, replicating a previous finding with rats. However, more food was presented with longer initial links, confounding the disrupter and initial-link duration. In Experiment 2, presession feeding was used instead and eliminated the negative relation between relative resistance to change and preference, but relative resistance to change was not sensitive to relative terminal-link reinforcement rates. In Experiment 3, with more extreme relative terminal-link reinforcement rates, increasing initial-link duration similarly decreased preference and relative resistance to change for the richer terminal link. Thus, when conditions of disruption are equal and assessed under the appropriate reinforcement conditions, changes in temporal context impact relative resistance to change and preference similarly.

Triphasic spike-timing-dependent plasticity organizes networks to produce robust sequences of neural activity

PubMed Central

Waddington, Amelia; Appleby, Peter A.; De Kamps, Marc; Cohen, Netta

2012-01-01

Synfire chains have long been proposed to generate precisely timed sequences of neural activity. Such activity has been linked to numerous neural functions including sensory encoding, cognitive and motor responses. In particular, it has been argued that synfire chains underlie the precise spatiotemporal firing patterns that control song production in a variety of songbirds. Previous studies have suggested that the development of synfire chains requires either initial sparse connectivity or strong topological constraints, in addition to any synaptic learning rules. Here, we show that this necessity can be removed by using a previously reported but hitherto unconsidered spike-timing-dependent plasticity (STDP) rule and activity-dependent excitability. Under this rule the network develops stable synfire chains that possess a non-trivial, scalable multi-layer structure, in which relative layer sizes appear to follow a universal function. Using computational modeling and a coarse grained random walk model, we demonstrate the role of the STDP rule in growing, molding and stabilizing the chain, and link model parameters to the resulting structure. PMID:23162457

Emergence of the A20/ABIN-mediated inhibition of NF-κB signaling via modifying the ubiquitinated proteins in a basal chordate.

PubMed

Yuan, Shaochun; Dong, Xiangru; Tao, Xin; Xu, Liqun; Ruan, Jie; Peng, Jian; Xu, Anlong

2014-05-06

In the past decade, ubiquitination has been well documented to have multifaceted roles in regulating NF-κB activation in mammals. However, its function, especially how deubiquitinating enzymes balance the NF-κB activation, remains largely elusive in invertebrates. Investigating bbtA20 and its binding proteins, bbt A20-binding inhibitor of NF-κB (bbtABIN1) and bbtABIN2, in Chinese amphioxus Branchiostoma belcheri tsingtauense, we found that bbtABIN2 can colocalize and compete with bbt TNF receptor-associated factor 6 to connect the K63-linked polyubiquitin chains, whereas bbtABIN1 physically links bbtA20 to bbt NF-κB essential modulator (bbtNEMO) to facilitate the K48-linked ubiquitination of bbtNEMO. Similar to human A20, bbtA20 is a dual enzyme that removes the K63-linked polyubiquitin chains and builds the K48-linked polyubiquitin chains on bbt receptor-interacting serine/threonine protein kinase 1b, leading to the inhibition of NF-κB signaling. Our study not only suggests that ubiquitination is an ancient strategy in regulating NF-κB activation but also provides the first evidence, to our knowledge, for ABINs/A20-mediated inhibition of NF-κB via modifying the ubiquitinated proteins in a basal chordate, adding information on the stepwise development of vertebrate innate immune signaling.

Molecular basis for the unique deubiquitinating activity of the NF-kappaB inhibitor A20.

PubMed

Lin, Su-Chang; Chung, Jee Y; Lamothe, Betty; Rajashankar, Kanagalaghatta; Lu, Miao; Lo, Yu-Chih; Lam, Amy Y; Darnay, Bryant G; Wu, Hao

2008-02-15

Nuclear factor kappaB (NF-kappaB) activation in tumor necrosis factor, interleukin-1, and Toll-like receptor pathways requires Lys63-linked nondegradative polyubiquitination. A20 is a specific feedback inhibitor of NF-kappaB activation in these pathways that possesses dual ubiquitin-editing functions. While the N-terminal domain of A20 is a deubiquitinating enzyme (DUB) for Lys63-linked polyubiquitinated signaling mediators such as TRAF6 and RIP, its C-terminal domain is a ubiquitin ligase (E3) for Lys48-linked degradative polyubiquitination of the same substrates. To elucidate the molecular basis for the DUB activity of A20, we determined its crystal structure and performed a series of biochemical and cell biological studies. The structure reveals the potential catalytic mechanism of A20, which may be significantly different from papain-like cysteine proteases. Ubiquitin can be docked onto a conserved A20 surface; this interaction exhibits charge complementarity and no steric clash. Surprisingly, A20 does not have specificity for Lys63-linked polyubiquitin chains. Instead, it effectively removes Lys63-linked polyubiquitin chains from TRAF6 without dissembling the chains themselves. Our studies suggest that A20 does not act as a general DUB but has the specificity for particular polyubiquitinated substrates to assure its fidelity in regulating NF-kappaB activation in the tumor necrosis factor, interleukin-1, and Toll-like receptor pathways.

Surprising Impact of Remote Groups on the Folding-Unfolding and Dimer-Chain Equilibria of Bifunctionl H-Bonding Unimers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Rui; Cheng, Shuang; Baker, Erin Shammel

2016-01-28

Oligoamide 1, consisting of two H-bonding units linked by a trimethylene linker, was previously found to form a very stable, folded dimer. In this work, replacing the side chains and end groups of 1 led to derivatives that show the surprising impact of end groups on the folding and dimer-chain equilibria of the resultant molecules.

Operational Evaluation of Tug/Barge Systems.

DTIC Science & Technology

1979-07-01

it would be expected that push-towing on the oceans would have developed long ago. However, the simple pin and wire/ chain lashings used on the rivers...better maneuverability available with push-towing. Thus, they began deepening the notches and using sophisticated cable/ chain linking and chafing...denied. But since mechanical linkages would result in increased manning rd capital costs, they instead began to develop improved cable/ chain linkages

Hypertension, dyslipidemia, and insulin resistance: links in a chain or spokes on a wheel?

PubMed

Hopkins, P N; Hunt, S C; Wu, L L; Williams, G H; Williams, R R

1996-08-01

Rather than a link in a causal chain leading to hypertension, insulin resistance and resultant hyperinsulinemia may be 'spokes on a wheel', with central or visceral obesity as the postulated hub of the wheel. Hypertension, hypertriglyceridemia and high density lipoprotein cholesterol are depicted as other spokes. Newly identified metabolic pathways in adipose tissue or the modulating effects of various predisposing genes may lead to variable expression of various components of the multiple metabolic syndrome in individuals with a predisposition to the collection of visceral fat.

Edible energy: balancing inputs and waste in food supply chain and biofuels from algae

NASA Astrophysics Data System (ADS)

Alimonti, Gianluca; Brambilla, Riccardo; Pileci, Rosaria; Romano, Riccardo; Rosa, Francesca; Spinicci, Luca

2017-01-01

Energy is life. Without it there is no water, there is no nutrition. Man's ability to live, grow, produce wealth is closely linked to the energy availability and use. Fire has been the first energy conversion technology; since that moment, the link between energy and progress has been indissoluble. Nowadays, a much greater energy input into the food supply chain has made a much higher food production possible. This might have an impact on the water availability. Algae are a promising solution for the energy-food-water nexus.

Effects of Xylan Side-Chain Substitutions on Xylan-Cellulose Interactions and Implications for Thermal Pretreatment of Cellulosic Biomass.

PubMed

Pereira, Caroline S; Silveira, Rodrigo L; Dupree, Paul; Skaf, Munir S

2017-04-10

Lignocellulosic biomass is mainly constituted by cellulose, hemicellulose, and lignin and represents an important resource for the sustainable production of biofuels and green chemistry materials. Xylans, a common hemicellulose, interact with cellulose and often exhibit various side chain substitutions including acetate, (4-O-methyl) glucuronic acid, and arabinose. Recent studies have shown that the distribution of xylan substitutions is not random, but follows patterns that are dependent on the plant taxonomic family and cell wall type. Here, we use molecular dynamics simulations to investigate the role of substitutions on xylan interactions with the hydrophilic cellulose face, using the recently discovered xylan decoration pattern of the conifer gymnosperms as a model. The results show that α-1,2-linked substitutions stabilize the binding of single xylan chains independently of the nature of the substitution and that Ca 2+ ions can mediate cross-links between glucuronic acid substitutions of two neighboring xylan chains, thus stabilizing binding. At high temperature, xylans move from the hydrophilic to the hydrophobic cellulose surface and are also stabilized by Ca 2+ cross-links. Our results help to explain the role of substitutions on xylan-cellulose interactions, and improve our understanding of the plant cell wall architecture and the fundamentals of biomass pretreatments.

Gel Point Suppression in RAFT Polymerization of Pure Acrylic Cross-Linker Derived from Soybean Oil.

PubMed

Yan, Mengguo; Huang, Yuerui; Lu, Mingjia; Lin, Fang-Yi; Hernández, Nacú B; Cochran, Eric W

2016-08-08

Here we report the reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylated epoxidized soybean oil (AESO), a cross-linker molecule, to high conversion (>50%) and molecular weight (>100 kDa) without macrogelation. Surprisingly, gelation is suppressed in this system far beyond the expectations predicated both on Flory-Stockmeyer theory and multiple other studies of RAFT polymerization featuring cross-linking moieties. By varying AESO and initiator concentrations, we show how intra- versus intermolecular cross-linking compete, yielding a trade-off between the degree of intramolecular linkages and conversion at gel point. We measured polymer chain characteristics, including molecular weight, chain dimensions, polydispersity, and intrinsic viscosity, using multidetector gel permeation chromatography and NMR to track polymerization kinetics. We show that not only the time and conversion at macrogelation, but also the chain architecture, is largely affected by these reaction conditions. At maximal AESO concentration, the gel point approaches that predicted by the Flory-Stockmeyer theory, and increases in an exponential fashion as the AESO concentration decreases. In the most dilute solutions, macrogelation cannot be detected throughout the entire reaction. Instead, cyclization/intramolecular cross-linking reactions dominate, leading to microgelation. This work is important, especially in that it demonstrates that thermoplastic rubbers could be produced based on multifunctional renewable feedstocks.

Effects of Experience on Preference between Forced and Free Choice

ERIC Educational Resources Information Center

Ono, Koichi

2004-01-01

Preference between forced choice and free choice in concurrent-chain schedules of reinforcement was investigated in pigeons after exposure to particular combinations of terminal links. In Experiment 1, in which terminal links always ended with reinforcers, one of three pairs of terminal links was arranged as preexposure: (a) both terminal links…

Chain Assembly and Disassembly Processes Differently Affect the Conformational Space of Ubiquitin Chains.

PubMed

Kniss, Andreas; Schuetz, Denise; Kazemi, Sina; Pluska, Lukas; Spindler, Philipp E; Rogov, Vladimir V; Husnjak, Koraljka; Dikic, Ivan; Güntert, Peter; Sommer, Thomas; Prisner, Thomas F; Dötsch, Volker

2018-02-06

Ubiquitination is the most versatile posttranslational modification. The information is encoded by linkage type as well as chain length, which are translated by ubiquitin binding domains into specific signaling events. Chain topology determines the conformational space of a ubiquitin chain and adds an additional regulatory layer to this ubiquitin code. In particular, processes that modify chain length will be affected by chain conformations as they require access to the elongation or cleavage sites. We investigated conformational distributions in the context of chain elongation and disassembly using pulsed electron-electron double resonance spectroscopy in combination with molecular modeling. Analysis of the conformational space of diubiquitin revealed conformational selection or remodeling as mechanisms for chain recognition during elongation or hydrolysis, respectively. Chain elongation to tetraubiquitin increases the sampled conformational space, suggesting that a high intrinsic flexibility of K48-linked chains may contribute to efficient proteasomal degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-Consistent Field Lattice Model for Polymer Networks.

PubMed

Tito, Nicholas B; Storm, Cornelis; Ellenbroek, Wouter G

2017-12-26

A lattice model based on polymer self-consistent field theory is developed to predict the equilibrium statistics of arbitrary polymer networks. For a given network topology, our approach uses moment propagators on a lattice to self-consistently construct the ensemble of polymer conformations and cross-link spatial probability distributions. Remarkably, the calculation can be performed "in the dark", without any prior knowledge on preferred chain conformations or cross-link positions. Numerical results from the model for a test network exhibit close agreement with molecular dynamics simulations, including when the network is strongly sheared. Our model captures nonaffine deformation, mean-field monomer interactions, cross-link fluctuations, and finite extensibility of chains, yielding predictions that differ markedly from classical rubber elasticity theory for polymer networks. By examining polymer networks with different degrees of interconnectivity, we gain insight into cross-link entropy, an important quantity in the macroscopic behavior of gels and self-healing materials as they are deformed.

Crystal structures of five (2-chloro­quinolin-3-yl)methyl ethers: supra­molecular assembly in one and two dimensions mediated by hydrogen bonding and π–π stacking

PubMed Central

Sowmya, Haliwana B. V.; Suresha Kumara, Tholappanavara H.; Gopalpur, Nagendrappa; Jasinski, Jerry P.; Millikan, Sean P.; Yathirajan, Hemmige S.; Glidewell, Christopher

2015-01-01

In the mol­ecules of the title compounds, methyl 5-bromo-2-[(2-chloro­quinolin-3-yl)meth­oxy]benzoate, C18H13BrClNO3, (I), methyl 5-bromo-2-[(2-chloro-6-methyl­quinolin-3-yl)meth­oxy]benzoate, C19H15BrClNO3, (II), methyl 2-[(2-chloro-6-methyl­quinolin-3-yl)meth­oxy]benzoate, C19H16ClNO3, (III), which crystallizes with Z′ = 4 in space group P212121, and 2-chloro-3-[(naphthalen-1-yl­oxy)meth­yl]quinoline, C20H14ClNO, (IV), the non-H atoms are nearly coplanar, but in {5-[(2-chloro­quinolin-3-yl)meth­oxy]-4-(hy­droxy­meth­yl)-6-methyl­pyridin-3-yl}methanol, C18H17ClN2O3, (V), the planes of the quinoline unit and of the unfused pyridine ring are almost parallel, although not coplanar. The mol­ecules of (I) are linked by two independent π–π stacking inter­actions to form chains, but there are no hydrogen bonds present in the structure. In (II), the mol­ecules are weakly linked into chains by a single type of π–π stacking inter­action. In (III), three of the four independent mol­ecules are linked by π–π stacking inter­actions but the other mol­ecule does not participate in such inter­actions. Weak C—H⋯O hydrogen bonds link the mol­ecules into three types of chains, two of which contain just one type of independent mol­ecule while the third type of chain contains two types of mol­ecule. The mol­ecules of (IV) are linked into chains by a C—H⋯π(arene) hydrogen bond, but π–π stacking inter­actions are absent. In (V), there is an intra­molecular O—H⋯O hydrogen bond, and mol­ecules are linked into sheets by a combination of O—H⋯N hydrogen bonds and π–π stacking inter­actions. PMID:26090133

The Vps27/Hrs/STAM (VHS) Domain of the Signal-transducing Adaptor Molecule (STAM) Directs Associated Molecule with the SH3 Domain of STAM (AMSH) Specificity to Longer Ubiquitin Chains and Dictates the Position of Cleavage*

PubMed Central

Baiady, Nardeen; Padala, Prasanth; Mashahreh, Bayan; Cohen-Kfir, Einav; Todd, Emily A.; Du Pont, Kelly E.; Berndsen, Christopher E.; Wiener, Reuven

2016-01-01

The deubiquitinating enzyme associated molecule with the SH3 domain of STAM (AMSH) is crucial for the removal of ubiquitin molecules during receptor-mediated endocytosis and lysosomal receptor sorting. AMSH interacts with signal transducing adapter molecule (STAM) 1 or 2, which enhances the activity of AMSH through an unknown mechanism. This stimulation is dependent on the ubiquitin-interacting motif of STAM. Here we investigate the specific mechanism of AMSH stimulation by STAM proteins and the role of the STAM Vps27/Hrs/STAM domain. We show that, in the presence of STAM, the length of the ubiquitin chains affects the apparent cleavage rate. Through measurement of the chain cleavage kinetics, we found that, although the kcat of Lys63-linked ubiquitin chain cleavage was comparable for di- and tri-ubiquitin, the Km value was lower for tri-ubiquitin. This increased affinity for longer chains was dependent on the Vps27/Hrs/STAM domain of STAM and required that the substrate ubiquitin chain contain homogenous Lys63-linkages. In addition, STAM directed AMSH cleavage toward the distal isopeptide bond in tri-ubiquitin chains. Finally, we generated a structural model of AMSH-STAM to show how the complex binds Lys63-linked ubiquitin chains and cleaves at the distal end. These data show how a deubiquitinating enzyme-interacting protein dictates the efficiency and specificity of substrate cleavage. PMID:26601948

Thermoplastic tape compaction device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, V.W.

1994-12-27

A device is disclosed for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin bandmore » of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite. 5 figures.« less

Thermoplastic tape compaction device

DOEpatents

Campbell, V.W.

1994-12-27

A device is disclosed for bonding a thermoplastic tape to a substrate to form a fully consolidated composite. This device has an endless chain associated with a frame so as to rotate in a plane that is perpendicular to a long dimension of the tape, the chain having pivotally connected chain links with each of the links carrying a flexible foot member that extends outwardly from the chain. A selected number of the foot members contact the tape, after the heating thereof, to cause the heated tape to bond to the substrate. The foot members are each a thin band of metal oriented transversely to the chain, with a flexibility and width and length to contact the tape so as to cause the tape to conform to the substrate to achieve consolidation of the tape and the substrate. A biased leaf-type spring within the frame bears against an inner surface of the chain to provide the compliant pressure necessary to bond the tape to the substrate. The chain is supported by sprockets on shafts rotatably supported in the frame and, in one embodiment, one of the shafts has a drive unit to produce rotation such that the foot members in contact with the tape move at the same speed as the tape. Cooling jets are positioned along the frame to cool the resultant consolidated composite. 5 figures.

Power-law creep behavior of a semiflexible chain.

PubMed

Majumdar, Arnab; Suki, Béla; Rosenblatt, Noah; Alencar, Adriano M; Stamenović, Dimitrije

2008-10-01

Rheological properties of adherent cells are essential for their physiological functions, and microrheological measurements on living cells have shown that their viscoelastic responses follow a weak power law over a wide range of time scales. This power law is also influenced by mechanical prestress borne by the cytoskeleton, suggesting that cytoskeletal prestress determines the cell's viscoelasticity, but the biophysical origins of this behavior are largely unknown. We have recently developed a stochastic two-dimensional model of an elastically joined chain that links the power-law rheology to the prestress. Here we use a similar approach to study the creep response of a prestressed three-dimensional elastically jointed chain as a viscoelastic model of semiflexible polymers that comprise the prestressed cytoskeletal lattice. Using a Monte Carlo based algorithm, we show that numerical simulations of the chain's creep behavior closely correspond to the behavior observed experimentally in living cells. The power-law creep behavior results from a finite-speed propagation of free energy from the chain's end points toward the center of the chain in response to an externally applied stretching force. The property that links the power law to the prestress is the chain's stiffening with increasing prestress, which originates from entropic and enthalpic contributions. These results indicate that the essential features of cellular rheology can be explained by the viscoelastic behaviors of individual semiflexible polymers of the cytoskeleton.

47 CFR 76.501 - Cross-ownership.

Code of Federal Regulations, 2014 CFR

2014-10-01

... vertical ownership chain and application of the relevant attribution benchmark to the resulting product, except that wherever the ownership percentage for any link in the chain exceeds 50%, it shall not be... (i); or (ii) the interest holder supplies over fifteen percent of the total weekly broadcast...

Creating world-class supply chains.

PubMed

Katzorke, M; Lee, W B

2000-08-01

This article will share knowledge in two areas: The elements of world-class supply chains and the linking processes from customers' customers to suppliers' suppliers and the management approaches needed to engage the people and the organization in an effective implementation process to achieve world-class status.

47 CFR 76.501 - Cross-ownership.

Code of Federal Regulations, 2010 CFR

2010-10-01

... vertical ownership chain and application of the relevant attribution benchmark to the resulting product, except that wherever the ownership percentage for any link in the chain exceeds 50%, it shall not be...); or (ii) the interest holder supplies over fifteen percent of the total weekly broadcast programming...

Polysialic acid in human milk. CD36 is a new member of mammalian polysialic acid-containing glycoprotein.

PubMed

Yabe, Uichiro; Sato, Chihiro; Matsuda, Tsukasa; Kitajima, Ken

2003-04-18

The neural cell adhesion molecule and the voltage-sensitive sodium channel alpha-subunit are the only two molecules in mammals known to be modified by alpha-2,8-linked polysialic acid (polySia). We found a new polySia-containing glycoprotein in human milk and identified it as CD36, a member of the B class of the scavenger receptor superfamily. The polySia-containing glycan chain(s) were removed by alkaline treatment but not by peptide:N-glycanase F digestion, indicating that milk CD36 contained polySia on O-linked glycan chain(s). Polysialylation of CD36 occurs not only in human milk but also in mouse milk. However, CD36 in human platelets is not polysialylated. PolySia CD36 is secreted in milk at any lactation stage and reaches peak level at 1 month after parturition. Thus, it is suggested that polySia of milk CD36 is significant for neonatal development in terms of protection and nutrition.

Quality and safety of herbal medical products: regulation and the need for quality assurance along the value chains.

PubMed

Heinrich, Michael

2015-07-01

Herbal medicines and products derived from them are a diverse group of products for which different (and often limited) levels of evidence are available. As importantly, such products generally vary in their composition and are at the end of an often poorly understood value chain, which often links producers in biodiversity rich countries with the large markets in the North. This paper discusses the current regulatory framework of such herbal medical products (with a focus on the UK) and using examples from our own metabolomic research on Curcumal longa L. (turmeric, Zingiberaceae) how value chains impact on the composition and quality (and thus the safety) of such products. Overall, our recent research demonstrates the need for studying the links between producers and consumers of commodities produced in provider countries and that plant metabolomics offer a novel way of assessing the chemical variability along a value chain. © 2015 The British Pharmacological Society.

Reduction in aggregation and energy transfer of quantum dots incorporated in polystyrene beads by kinetic entrapment due to cross-linking during polymerization.

PubMed

Vaidya, Shyam V; Couzis, Alex; Maldarelli, Charles

2015-03-17

We report the development of barcoded polystyrene microbeads, approximately 50 μm in diameter, which are encoded by incorporating multicolored semiconductor fluorescent nanocrystals (quantum dots or QDs) within the microbeads and using the emission spectrum of the embedded QDs as a spectral label. The polymer/nanocrystal bead composites are formed by polymerizing emulsified liquid droplets of styrene monomer and QDs suspended in an immiscible continuous phase (suspension polymerization). We focus specifically on the effect of divinylbenzene (DVB) added to cross-link the linearly growing styrene polymer chains and the effect of this cross-linking on the state of aggregation of the nanocrystals in the composite. Aggregated states of multicolor QDs give rise to nonradiative resonance energy transfer (RET) which distorts the emission label from a spectrum recorded in a reference solvent in which the nanocrystals are well dispersed and unaggregated. A simple barcode is chosen of a mixture of QDs emitting at 560 (yellow) and 620 nm (red). We find that for linear chain growth (no DVB), the QDs aggregate as is evident from the emission spectrum and the QD distribution as seen from confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM) images. Increasing the extent of cross-linking by the addition of DVB is shown to significantly decrease the aggregation and provide a clear label. We suggest that in the absence of cross-linking, linearly growing polymer chains, through enthalpic and entropic effects, drive the nanocrystals into inclusions, while cross-linking kinetically entraps the particle and prevents their aggregation.

Using the Chain Rule as the Key Link in Deriving the General Rules for Differentiation

ERIC Educational Resources Information Center

Sprows, David

2011-01-01

The standard approach to the general rules for differentiation is to first derive the power, product, and quotient rules and then derive the chain rule. In this short article we give an approach to these rules which uses the chain rule as the main tool in deriving the power, product, and quotient rules in a manner which is more student-friendly…

Going the Extra Mile: Enabling Joint Logistics for the Tactical War Fighter

DTIC Science & Technology

2010-05-04

few of the links when relocating hubs. Chains v. Networks Supply Chain Too brittle , long CPL, low clustering, simple pattern, simple control...Mass Service Perspective Efficiency Highly Optimized Brittle , Rigid Supply Chains vs Networked Cross-Service Mutual Support Cross-Enterprise...Storage and Distribution Centei\\" Army Logistician 39, no. 6 (November-December 2007): 40. 68 Glen R Dowling, "Army and Marine Joint Ammunition

In Vivo Ubiquitin Linkage-type Analysis Reveals that the Cdc48-Rad23/Dsk2 Axis Contributes to K48-Linked Chain Specificity of the Proteasome.

PubMed

Tsuchiya, Hikaru; Ohtake, Fumiaki; Arai, Naoko; Kaiho, Ai; Yasuda, Sayaka; Tanaka, Keiji; Saeki, Yasushi

2017-05-18

Ubiquitin-binding domain (UBD) proteins regulate numerous cellular processes, but their specificities toward ubiquitin chain types in cells remain obscure. Here, we perform a quantitative proteomic analysis of ubiquitin linkage-type selectivity of 14 UBD proteins and the proteasome in yeast. We find that K48-linked chains are directed to proteasomal degradation through selectivity of the Cdc48 cofactor Npl4. Mutating Cdc48 results in decreased selectivity, and lacking Rad23/Dsk2 abolishes interactions between ubiquitylated substrates and the proteasome. Among them, only Npl4 has K48 chain specificity in vitro. Thus, the Cdc48 complex functions as a K48 linkage-specifying factor upstream of Rad23/Dsk2 for proteasomal degradation. On the other hand, K63 chains are utilized in endocytic pathways, whereas both K48 and K63 chains are found in the MVB and autophagic pathways. Collectively, our results provide an overall picture of the ubiquitin network via UBD proteins and identify the Cdc48-Rad23/Dsk2 axis as a major route to the proteasome. Copyright © 2017 Elsevier Inc. All rights reserved.

Determinants of choice for pigeons and humans on concurrent-chains schedules of reinforcement.

PubMed

Belke, T W; Pierce, W D; Powell, R A

1989-09-01

Concurrent-chains schedules of reinforcement were arranged for humans and pigeons. Responses of humans were reinforced with tokens exchangeable for money, and key pecks of 4 birds were reinforced with food. Variable-interval 30-s and 40-s schedules operated in the terminal links of the chains. Condition 1 exposed subjects to variable-interval 90-s and variable-interval 30-s initial links, respectively. Conditions 2 and 3 arranged equal initial-link schedules of 40 s or 120 s. Experimental conditions tested the descriptive adequacy of five equations: reinforcement density, delay reduction, modified delay reduction, matching and maximization. Results based on choice proportions and switch rates during the initial links showed that pigeons behaved in accord with delay-reduction models, whereas humans maximized overall rate of reinforcement. As discussed by Logue and associates in self-control research, different types of reinforcement may affect sensitivity to delay differentially. Pigeons' responses were reinforced with food, a reinforcer that is consumable upon presentation. Humans' responses were reinforced with money, a reinforcer exchanged for consumable reinforcers after it was earned. Reinforcers that are immediately consumed may generate high sensitivity to delay and behavior described as delay reduction. Reinforces with longer times to consumption may generate low sensitivity to delay and behavior that maximizes overall payoff.

Cascaded H-bridge multilevel inverter for renewable energy generation

NASA Astrophysics Data System (ADS)

Pandey, Ravikant; Nath Tripathi, Ravi; Hanamoto, Tsuyoshi

2016-04-01

In this paper cascaded H-bridge multilevel inverter (CHBMLI) has been investigated for the application of renewable energy generation. Energy sources like solar, wind, hydro, biomass or combination of these can be manipulated to obtain alternative sources for renewable energy generation. These renewable energy sources have different electrical characteristics like DC or AC level so it is challenging to use generated power by connecting to grid or load directly. The renewable energy source require specific power electronics converter as an interface for conditioning generated power .The multilevel inverter can be utilized for renewable energy sources in two different modes, the power generation mode (stand-alone mode), and compensator mode (statcom). The performance of the multilevel inverter has been compared with two level inverter. In power generation mode CHBMLI supplies the active and reactive power required by the different loads. For operation in compensator mode the indirect current control based on synchronous reference frame theory (SRFT) ensures the grid operating in unity power factor and compensate harmonics and reactive power.

Optimal placement of FACTS devices using optimization techniques: A review

NASA Astrophysics Data System (ADS)

Gaur, Dipesh; Mathew, Lini

2018-03-01

Modern power system is dealt with overloading problem especially transmission network which works on their maximum limit. Today’s power system network tends to become unstable and prone to collapse due to disturbances. Flexible AC Transmission system (FACTS) provides solution to problems like line overloading, voltage stability, losses, power flow etc. FACTS can play important role in improving static and dynamic performance of power system. FACTS devices need high initial investment. Therefore, FACTS location, type and their rating are vital and should be optimized to place in the network for maximum benefit. In this paper, different optimization methods like Particle Swarm Optimization (PSO), Genetic Algorithm (GA) etc. are discussed and compared for optimal location, type and rating of devices. FACTS devices such as Thyristor Controlled Series Compensator (TCSC), Static Var Compensator (SVC) and Static Synchronous Compensator (STATCOM) are considered here. Mentioned FACTS controllers effects on different IEEE bus network parameters like generation cost, active power loss, voltage stability etc. have been analyzed and compared among the devices.

Interaction with bovine serum albumin of an anti-oxidative pectic arabinogalactan from Andrographis paniculata.

PubMed

Chatterjee, Udipta R; Ray, Sayani; Micard, Valérie; Ghosh, Debjani; Ghosh, Kanika; Bandyopadhyay, Shruti S; Ray, Bimalendu

2014-01-30

A pectic arabinogalactan was obtained from the leaves of Andrographis paniculata by aqueous extraction followed by α-amylase treatment, deproteination, and anion exchange chromatography. Methylation analysis, Smith degradation, and NMR spectroscopy indicated that it was a highly branched arabinogalactan containing a (1→3)-linked β-d-Galp main chain, substituted at O-6 by (1→6)-linked β-d-Galp side chains. The latter residues were substituted at O-3 by (1→5)- and (1→3)-linked α-l-Araf chains, and non reducing end-units of α-l-Araf and β-d-Galp. This homogeneous arabinogalactan (36 kDa), which contained phenolic acids, showed dose-dependent anti-oxidative properties. The phenolic acid moieties might be the functional sites. This arabinogalactan can form a complex with bovine serum albumin having binding constant K=6.48 × 10(6)/M. Thus, this study is an important step forward to investigate the involvement of arabinogalactan in processes including interaction with biologically important transport proteins. Copyright © 2013 Elsevier Ltd. All rights reserved.

Short chain fatty acid production and glucose responses by methane producers

USDA-ARS?s Scientific Manuscript database

Fermentation by gut microbiota has been linked to physiologic responses in the host. Methanogenic gut bacteria may remove more carbon from indigestible food matrices especially poorly digested carbohydrates. We sought to assess the effects of methane production on short chain fatty acid (SCFA) con...

Disease Compass- a navigation system for disease knowledge based on ontology and linked data techniques.

PubMed

Kozaki, Kouji; Yamagata, Yuki; Mizoguchi, Riichiro; Imai, Takeshi; Ohe, Kazuhiko

2017-06-19

Medical ontologies are expected to contribute to the effective use of medical information resources that store considerable amount of data. In this study, we focused on disease ontology because the complicated mechanisms of diseases are related to concepts across various medical domains. The authors developed a River Flow Model (RFM) of diseases, which captures diseases as the causal chains of abnormal states. It represents causes of diseases, disease progression, and downstream consequences of diseases, which is compliant with the intuition of medical experts. In this paper, we discuss a fact repository for causal chains of disease based on the disease ontology. It could be a valuable knowledge base for advanced medical information systems. We developed the fact repository for causal chains of diseases based on our disease ontology and abnormality ontology. This section summarizes these two ontologies. It is developed as linked data so that information scientists can access it using SPARQL queries through an Resource Description Framework (RDF) model for causal chain of diseases. We designed the RDF model as an implementation of the RFM for the fact repository based on the ontological definitions of the RFM. 1554 diseases and 7080 abnormal states in six major clinical areas, which are extracted from the disease ontology, are published as linked data (RDF) with SPARQL endpoint (accessible API). Furthermore, the authors developed Disease Compass, a navigation system for disease knowledge. Disease Compass can browse the causal chains of a disease and obtain related information, including abnormal states, through two web services that provide general information from linked data, such as DBpedia, and 3D anatomical images. Disease Compass can provide a complete picture of disease-associated processes in such a way that fits with a clinician's understanding of diseases. Therefore, it supports user exploration of disease knowledge with access to pertinent information from a variety of sources.

Critical appraisal of assumptions in chains of model calculations used to project local climate impacts for adaptation decision support—the case of Baakse Beek

NASA Astrophysics Data System (ADS)

van der Sluijs, Jeroen P.; Arjan Wardekker, J.

2015-04-01

In order to enable anticipation and proactive adaptation, local decision makers increasingly seek detailed foresight about regional and local impacts of climate change. To this end, the Netherlands Models and Data-Centre implemented a pilot chain of sequentially linked models to project local climate impacts on hydrology, agriculture and nature under different national climate scenarios for a small region in the east of the Netherlands named Baakse Beek. The chain of models sequentially linked in that pilot includes a (future) weather generator and models of respectively subsurface hydrogeology, ground water stocks and flows, soil chemistry, vegetation development, crop yield and nature quality. These models typically have mismatching time step sizes and grid cell sizes. The linking of these models unavoidably involves the making of model assumptions that can hardly be validated, such as those needed to bridge the mismatches in spatial and temporal scales. Here we present and apply a method for the systematic critical appraisal of model assumptions that seeks to identify and characterize the weakest assumptions in a model chain. The critical appraisal of assumptions presented in this paper has been carried out ex-post. For the case of the climate impact model chain for Baakse Beek, the three most problematic assumptions were found to be: land use and land management kept constant over time; model linking of (daily) ground water model output to the (yearly) vegetation model around the root zone; and aggregation of daily output of the soil hydrology model into yearly input of a so called ‘mineralization reduction factor’ (calculated from annual average soil pH and daily soil hydrology) in the soil chemistry model. Overall, the method for critical appraisal of model assumptions presented and tested in this paper yields a rich qualitative insight in model uncertainty and model quality. It promotes reflectivity and learning in the modelling community, and leads to well informed recommendations for model improvement.

Interstaple Dithiol Cross-Linking in Au(25)(SR)(18) Nanomolecules: A Combined Mass Spectrometric and Computational Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Deen; Dass, Amala; Tschumper, Gregory

2011-01-01

A systematic study of cross-linking chemistry of the Au{sub 25}(SR){sub 18} nanomolecule by dithiols of varying chain length, HS-(CH2)n-SH where n = 2, 3, 4, 5, and 6, is presented here. Monothiolated Au{sub 25} has six [RSAuSRAuSR] staple motifs on its surface, and MALDI mass spectrometry data of the ligand exchanged clusters show that propane (C3) and butane (C4) dithiols have ideal chain lengths for interstaple cross-linking and that up to six C3 or C4 dithiols can be facilely exchanged onto the cluster surface. Propanedithiol predominately exchanges with two monothiols at a time, making cross-linking bridges, while butanedithiol can exchangemore » with either one or two monothiols at a time. The extent of cross-linking can be controlled by the Au{sub 25}(SR){sub 18} to dithiol ratio, the reaction time of ligand exchange, or the addition of a hydrophobic tail to the dithiol. MALDI MS suggests that during ethane (C2) dithiol exchange, two ethanedithiols become connected by a disulfide bond; this result is supported by density functional theory (DFT) prediction of the optimal chain length for the intrastaple coupling. Both optical absorption spectroscopy and DFT computations show that the electronic structure of the Au{sub 25} nanomolecule retains its main features after exchange of up to eight monothiol ligands.« less

Nanoparticle (star polymer) delivery of nitric oxide effectively negates Pseudomonas aeruginosa biofilm formation.

PubMed

Duong, Hien T T; Jung, Kenward; Kutty, Samuel K; Agustina, Sri; Adnan, Nik Nik M; Basuki, Johan S; Kumar, Naresh; Davis, Thomas P; Barraud, Nicolas; Boyer, Cyrille

2014-07-14

Biofilms are increasingly recognized as playing a major role in human infectious diseases, as they can form on both living tissues and abiotic surfaces, with serious implications for applications that rely on prolonged exposure to the body such as implantable biomedical devices or catheters. Therefore, there is an urgent need to develop improved therapeutics to effectively eradicate unwanted biofilms. Recently, the biological signaling molecule nitric oxide (NO) was identified as a key regulator of dispersal events in biofilms. In this paper, we report a new class of core cross-linked star polymers designed to store and release nitric oxide, in a controlled way, for the dispersion of biofilms. First, core cross-linked star polymers were prepared by reversible addition-fragmentation chain transfer polymerization (RAFT) via an arm first approach. Poly(oligoethylene methoxy acrylate) chains were synthesized by RAFT polymerization, and then chain extended in the presence of 2-vinyl-4,4-dimethyl-5-oxazolone monomer (VDM) with N,N-methylenebis(acrylamide) employed as a cross-linker to yield functional core cross-linked star polymers. Spermine was successfully attached to the star core by reaction with VDM. Finally, the secondary amine groups were reacted with NO gas to yield NO-core cross-linked star polymers. The core cross-linked star polymers were found to release NO in a controlled, slow delivery in bacterial cultures showing great efficacy in preventing both cell attachment and biofilm formation in Pseudomonas aeruginosa over time via a nontoxic mechanism, confining bacterial growth to the suspended liquid.

ALARA: The next link in a chain of activation codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, P.P.H.; Henderson, D.L.

1996-12-31

The Adaptive Laplace and Analytic Radioactivity Analysis [ALARA] code has been developed as the next link in the chain of DKR radioactivity codes. Its methods address the criticisms of DKR while retaining its best features. While DKR ignored loops in the transmutation/decay scheme to preserve the exactness of the mathematical solution, ALARA incorporates new computational approaches without jeopardizing the most important features of DKR`s physical modelling and mathematical methods. The physical model uses `straightened-loop, linear chains` to achieve the same accuracy in the loop solutions as is demanded in the rest of the scheme. In cases where a chain hasmore » no loops, the exact DKR solution is used. Otherwise, ALARA adaptively chooses between a direct Laplace inversion technique and a Laplace expansion inversion technique to optimize the accuracy and speed of the solution. All of these methods result in matrix solutions which allow the fastest and most accurate solution of exact pulsing histories. Since the entire history is solved for each chain as it is created, ALARA achieves the optimum combination of high accuracy, high speed and low memory usage. 8 refs., 2 figs.« less

Positioning of the carboxamide side chain in 11-oxo-11H-indeno[1,2-b]quinolinecarboxamide anticancer agents: effects on cytotoxicity.

PubMed

Deady, L W; Desneves, J; Kaye, A J; Finlay, G J; Baguley, B C; Denny, W A

2001-02-01

A series of 11-oxo-11H-indeno[1,2-b]quinolines bearing a carboxamide-linked cationic side chain at various positions on the chromophore was studied to determine structure-activity relationships between cytotoxicity and the position of the side chain. The compounds were prepared by Pfitzinger synthesis from an appropriate isatin and 1-indanone, followed by various oxidative steps, to generate the required carboxylic acids. The 4- and 6-carboxamides (with the side chain on a terminal ring, off the short axis of the chromophore) were effective cytotoxins. The dimeric 4- and 6-linked analogues were considerably more cytotoxic than the parent monomers, but had broadly similar activities. In contrast, analogues with side chains at the 8-position (on a terminal ring but off the long axis of the chromophore) or 10-position (off the short axis of the chromophore but in a central ring) were drastically less effective. The 4,10- and 6,10-biscarboxamides had activities between those of the corresponding parent monocarboxamides. The first of these showed good activity against advanced subcutaneous colon 38 tumours in mice.

Identification of an O-linked repetitive glycan chain of the polar flagellum flagellin of Azospirillum brasilense Sp7.

PubMed

Belyakov, Alexei Ye; Burygin, Gennady L; Arbatsky, Nikolai P; Shashkov, Alexander S; Selivanov, Nikolai Yu; Matora, Larisa Yu; Knirel, Yuriy A; Shchyogolev, Sergei Yu

2012-11-01

This is the first report to have identified an O-linked repetitive glycan in bacterial flagellin, a structural protein of the flagellum. Studies by sugar analysis, Smith degradation, (1)H and (13)C NMR spectroscopy, and mass spectrometry showed that the glycan chains of the polar flagellum flagellin of the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp7 are represented by a polysaccharide with a molecular mass of 7.7 kDa, which has a branched tetrasaccharide repeating unit of the following structure: Copyright © 2012. Published by Elsevier Ltd.

Vinclozolin: 3-(3,5-di-chloro-phen-yl)-5-ethenyl-5-methyl-1,3-oxazolidine-2,4-dione.

PubMed

Cho, Seonghwa; Kim, Jineun; Lee, Sangjin; Kim, Tae Ho

2014-07-01

In the title compound, C12H9Cl2NO3, which is the fungicide vinclozolin, the dihedral angle between the oxazolidine ring mean plane [r.m.s. deviation = 0.029 Å] and the benzene ring is 77.55 (8)°. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming chains along [010]. The chains are linked by short Cl⋯Cl contacts [3.4439 (3) and 3.5798 (3) Å], resulting in a three-dimensional architecture.

Discover the missing links in the inventory knowledge chain--achieve 98% integrity in just 90 days? Yes you can!

PubMed

Ribar, T F

2000-05-01

You don't need any imagination to understand how to reconnect the Missing Links in the Knowledge Chain to improvement. The corrective action plan has been described clearly in eight easy steps that everyone can and should execute immediately to get their inventory integrity permanently up to 95 to 98% and keep it there. Nothing has been left to the imagination or to conjecture. This is the "how to" prescription to getting it done. It has worked effectively for others. It can work for you too.

Benzil bis-(ketazine).

PubMed

Patra, Goutam Kumar; Mukherjee, Anindita; Ng, Seik Weng

2009-07-04

1,1',2,2'-tetra-phenyl-2,2'-azinodiethanone), C(28)H(20)N(2)O(2), was obtained by the reaction of benzil monohydrazone with chromium(III) nitrate. The dibenzyl-idene hydrazine unit is nearly planar (r.m.s. deviation = 0.073 Å) and the two benzoyl units are oriented almost perpendicular to it [dihedral angle = 87.81 (2), 87.81 (2)°]. The mol-ecules are linked into chains along the c axis by C-H⋯O hydrogen bonds and the chains are cross-linked via C-H⋯π inter-actions involving the benzoyl phenyl rings.

A Bayesian method for inferring transmission chains in a partially observed epidemic.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marzouk, Youssef M.; Ray, Jaideep

2008-10-01

We present a Bayesian approach for estimating transmission chains and rates in the Abakaliki smallpox epidemic of 1967. The epidemic affected 30 individuals in a community of 74; only the dates of appearance of symptoms were recorded. Our model assumes stochastic transmission of the infections over a social network. Distinct binomial random graphs model intra- and inter-compound social connections, while disease transmission over each link is treated as a Poisson process. Link probabilities and rate parameters are objects of inference. Dates of infection and recovery comprise the remaining unknowns. Distributions for smallpox incubation and recovery periods are obtained from historicalmore » data. Using Markov chain Monte Carlo, we explore the joint posterior distribution of the scalar parameters and provide an expected connectivity pattern for the social graph and infection pathway.« less

Risk evaluation framework and selected metrics for tank cars carrying hazardous materials.

DOT National Transportation Integrated Search

2015-05-01

This report presents an analysis of train accident and hazmat release data to quantify the likelihood of a hazmat release. The harm caused : by a hazmat release is characterized as the end result of a chain of events, with each link in the chain bein...

The Effect of Conditioned Reinforcement Rate on Choice: A Review

ERIC Educational Resources Information Center

Fantino, Edmund; Romanowich, Paul

2007-01-01

We review the nature of conditioned reinforcement, including evidence that conditioned reinforcers maintain choice behavior in concurrent schedules and that they elevate responding in the terminal links of concurrent-chains schedules. A question has resurfaced recently: Do theories of choice in concurrent-chains schedules need to include a term…

29 CFR 1910.184 - Slings.

Code of Federal Regulations, 2010 CFR

2010-07-01

... alloy steel chain, wire rope, metal mesh, natural or synthetic fiber rope (conventional three strand... steel chain sling or wire rope sling. (See Fig. N-184-3.) Mechanical coupling link is a nonwelded... Slings 6×19 and 6×37 Classification Improved Plow Steel Grade Rope With Independent Wire Rope Core (IWRC...

29 CFR 1910.184 - Slings.

Code of Federal Regulations, 2011 CFR

2011-07-01

... alloy steel chain, wire rope, metal mesh, natural or synthetic fiber rope (conventional three strand... steel chain sling or wire rope sling. (See Fig. N-184-3.) Mechanical coupling link is a nonwelded... Slings 6×19 and 6×37 Classification Improved Plow Steel Grade Rope With Independent Wire Rope Core (IWRC...

US vaccine refrigeration guidelines: loose links in the cold chain.

PubMed

McColloster, Patrick J

2011-05-01

This commentary compares Centers for Disease Control (CDC) guidelines for vaccine storage with international cold chain standards. Problems related to the use of domestic refrigerators in clinical settings are discussed. Optimal vaccine refrigerator design characteristics are summarized. The adoption of World Health Organization storage recommendations is advised.

Regulation of Chemokine Expression by Lipopolysaccharide In Vitro and In Vivo

DTIC Science & Technology

2002-06-10

chain, the core polysaccharide , and the lipid A domain (Figure 1A). The hydrophilic O-specific chain is a polymer of repeating oligosaccharide units...necessary for protection from phagocytosis and complement-mediated lysis in vivo (9, 10). Linking the O-specific chain to lipid A is a core polysaccharide ...region that is relatively conserved among bacterial families on the basis of its monosaccharide composition. Among the common elements in the

Traveling-wave solutions in continuous chains of unidirectionally coupled oscillators

NASA Astrophysics Data System (ADS)

Glyzin, S. D.; Kolesov, A. Yu; Rozov, N. Kh

2017-12-01

Proposed is a mathematical model of a continuous annular chain of unidirectionally coupled generators given by certain nonlinear advection-type hyperbolic boundary value problem. Such problems are constructed by a limit transition from annular chains of unidirectionally coupled ordinary differential equations with an unbounded increase in the number of links. It is shown that any preassigned finite number of stable periodic motions of the traveling-wave type can coexist in the model.

P3h3-null and Sc65-null Mice Phenocopy the Collagen Lysine Under-hydroxylation and Cross-linking Abnormality of Ehlers-Danlos Syndrome Type VIA.

PubMed

Hudson, David M; Weis, MaryAnn; Rai, Jyoti; Joeng, Kyu Sang; Dimori, Milena; Lee, Brendan H; Morello, Roy; Eyre, David R

2017-03-03

Tandem mass spectrometry was applied to tissues from targeted mutant mouse models to explore the collagen substrate specificities of individual members of the prolyl 3-hydroxylase (P3H) gene family. Previous studies revealed that P3h1 preferentially 3-hydroxylates proline at a single site in collagen type I chains, whereas P3h2 is responsible for 3-hydroxylating multiple proline sites in collagen types I, II, IV, and V. In screening for collagen substrate sites for the remaining members of the vertebrate P3H family, P3h3 and Sc65 knock-out mice revealed a common lysine under-hydroxylation effect at helical domain cross-linking sites in skin, bone, tendon, aorta, and cornea. No effect on prolyl 3-hydroxylation was evident on screening the spectrum of known 3-hydroxyproline sites from all major tissue collagen types. However, collagen type I extracted from both Sc65 -/- and P3h3 -/- skin revealed the same abnormal chain pattern on SDS-PAGE with an overabundance of a γ 112 cross-linked trimer. The latter proved to be from native molecules that had intramolecular aldol cross-links at each end. The lysine under-hydroxylation was shown to alter the divalent aldimine cross-link chemistry of mutant skin collagen. Furthermore, the ratio of mature HP/LP cross-links in bone of both P3h3 -/- and Sc65 -/- mice was reversed compared with wild type, consistent with the level of lysine under-hydroxylation seen in individual chains at cross-linking sites. The effect on cross-linking lysines was quantitatively very similar to that previously observed in EDS VIA human and Plod1 -/- mouse tissues, suggesting that P3H3 and/or SC65 mutations may cause as yet undefined EDS variants. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Model Predictive Control techniques with application to photovoltaic, DC Microgrid, and a multi-sourced hybrid energy system

NASA Astrophysics Data System (ADS)

Shadmand, Mohammad Bagher

Renewable energy sources continue to gain popularity. However, two major limitations exist that prevent widespread adoption: availability and variability of the electricity generated and the cost of the equipment. The focus of this dissertation is Model Predictive Control (MPC) for optimal sized photovoltaic (PV), DC Microgrid, and multi-sourced hybrid energy systems. The main considered applications are: maximum power point tracking (MPPT) by MPC, droop predictive control of DC microgrid, MPC of grid-interaction inverter, MPC of a capacitor-less VAR compensator based on matrix converter (MC). This dissertation firstly investigates a multi-objective optimization technique for a hybrid distribution system. The variability of a high-penetration PV scenario is also studied when incorporated into the microgrid concept. Emerging (PV) technologies have enabled the creation of contoured and conformal PV surfaces; the effect of using non-planar PV modules on variability is also analyzed. The proposed predictive control to achieve maximum power point for isolated and grid-tied PV systems speeds up the control loop since it predicts error before the switching signal is applied to the converter. The low conversion efficiency of PV cells means we want to ensure always operating at maximum possible power point to make the system economical. Thus the proposed MPPT technique can capture more energy compared to the conventional MPPT techniques from same amount of installed solar panel. Because of the MPPT requirement, the output voltage of the converter may vary. Therefore a droop control is needed to feed multiple arrays of photovoltaic systems to a DC bus in microgrid community. Development of a droop control technique by means of predictive control is another application of this dissertation. Reactive power, denoted as Volt Ampere Reactive (VAR), has several undesirable consequences on AC power system network such as reduction in power transfer capability and increase in transmission loss if not controlled appropriately. Inductive loads which operate with lagging power factor consume VARs, thus load compensation techniques by capacitor bank employment locally supply VARs needed by the load. Capacitors are highly unreliable components due to their failure modes and aging inherent. Approximately 60% of power electronic devices failure such as voltage-source inverter based static synchronous compensator (STATCOM) is due to the use of aluminum electrolytic DC capacitors. Therefore, a capacitor-less VAR compensation is desired. This dissertation also investigates a STATCOM capacitor-less reactive power compensation that uses only inductors combined with predictive controlled matrix converter.

Transparent oxygen and water vapor barriers for flexible electronics using semi-crystalline polymer matrix thin films

NASA Astrophysics Data System (ADS)

Sehgal, Akhil

Electronic components such as organic light emitting diodes (OLED) and photo-voltaics have been of more focus with the advancement of technology. These electronics are susceptible to degradable in the presence of gases such as water vapor and oxygen. Being that these gases are constituents of the atmosphere and can be found in nearly every environment, certain protocols must take place to mitigate the issues that occur. New generation electronics are sensitive to oxidation and corrosion in the presence of extremely low concentrations of moisture and oxygen and therefore the development and improvements of gas barriers are vital for advancements in electronics technology. The improvements of appliances such as flexible solar cells and OLEDs require barriers that need to be flexible in order to achieve high longevity. The area of research has been focused on designing flexible polymer films with composite nanoparticles and cross-linking agents that have low permeability to moisture and oxygen gas. The polymers studied are in the family of methacrylates. Due to the properties of methacrylate polymers, it has been proposed that they are capable of having efficient barrier properties due to their ability to cross link and form crystalline structures with low chain mobility. The change in intensities of the FTIR peaks of different functional groups indicates the cross-linking and crystallinity of the polymer films. The UV-Vis data indicates high transparency of the films. SEM images of the films show continuous and well cured surfaces with minimal deviations, pores and defects. The addition of cross-linking agents and nanoparticles increased polymerization and cross-linking of the methacrylate polymer chains, therefore increasing inter-chain density and long range order. The incorporation of these additives increased the crystallinity of the films and by decreasing the distances and number of voids between polymer chains along with having minimal sorption sites for gases to bond to, the ability of gases such as moisture and oxygen to penetrate through the films has decreased.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilbur, Jeffrey D.; Gomez, Enrique D.; Ellsworth, Mark W.

A procedure for creating samples that can be repeatedly cycled between weakly aligned and strongly aligned states is described. Poly(styrene-b-isoprene) block copolymer samples were first shear-aligned and then cross-linked using a high energy electron beam. Samples with more than 1.0 cross-links per chain on average showed almost complete recovery of their initial alignment state even after 20 cycles of heating above the order–disorder transition temperature of the un-cross-linked block copolymer. Samples with 1.1 cross-links per chain, which showed over 90% loss of alignment on heating and almost 100% recovery of alignment on cooling, provided the best example of a reversiblemore » aligned-to-unaligned transition. Samples with lower cross-linking densities exhibited irreversible loss of alignment upon heating, while those with higher cross-linking densities exhibited less than 90% loss of alignment upon heating. Alignment was quantified by a technique that we call two color depolarized light scattering (TCDLS), an extension of the traditional depolarized light scattering experiment used to determine the state of order in block copolymers. Qualitative confirmation of our interpretation of TCDLS data was obtained by small-angle X-ray scattering and transmission electron microscopy.« less

Linking Biological Responses of Terrestrial N Eutrophication to the Final Ecosystem Goods and Services Classification System

NASA Astrophysics Data System (ADS)

Bell, M. D.; Clark, C.; Blett, T.

2015-12-01

The response of a biological indicator to N deposition can indicate that an ecosystem has surpassed a critical load and is at risk of significant change. The importance of this exceedance is often difficult to digest by policy makers and public audiences if the change is not linked to a familiar ecosystem endpoint. A workshop was held to bring together scientists, resource managers, and policy makers with expertise in ecosystem functioning, critical loads, and economics in an effort to identify the ecosystem services impacted by air pollution. This was completed within the framework of the Final Ecosystem Goods and Services (FEGS) Classification System to produce a product that identified distinct interactions between society and the effects of nitrogen pollution. From each change in a biological indicator, we created multiple ecological production functions to identify the cascading effects of the change to a measureable ecosystem service that a user interacts with either by enjoying, consuming, or appreciating the good or service, or using it as an input in the human economy. This FEGS metric was then linked to a beneficiary group that interacts with the service. Chains detailing the links from the biological indicator to the beneficiary group were created for aquatic and terrestrial acidification and eutrophication at the workshop, and here we present a subset of the workshop results by highlighting for 9 different ecosystems affected by terrestrial eutrophication. A total of 213 chains that linked to 37 unique FEGS metrics and impacted 15 beneficiary groups were identified based on nitrogen deposition mediated changes to biological indicators. The chains within each ecosystem were combined in flow charts to show the complex, overlapping relationships among biological indicators, ecosystem services, and beneficiary groups. Strength of relationship values were calculated for each chain based on support for the link in the scientific literature. We produced the complex diagrams to provide details to scientists and experts, identify research gaps, and understand the complexity of critical load exceedances. We then simplified the flow charts into stories that could produce an emotional connection and resonate with a general audience. These stories are important steps to breach the gaps between science and policy.

The role of hybrid ubiquitin chains in the MyD88 and other innate immune signalling pathways.

PubMed

Cohen, Philip; Strickson, Sam

2017-07-01

The adaptor protein MyD88 is required for signal transmission by toll-like receptors and receptors of the interleukin-1 family of cytokines. MyD88 signalling triggers the formation of Lys63-linked and Met1-linked ubiquitin (K63-Ub, M1-Ub) chains within minutes. The K63-Ub chains, which are formed by the E3 ubiquitin ligases TRAF6, Pellino1 and Pellino2, activate TAK1, the master kinase that switches on mitogen-activated protein (MAP) kinase cascades and initiates activation of the canonical IκB kinase (IKK) complex. The M1-Ub chains, which are formed by the linear ubiquitin chain assembly complex (LUBAC), bind to the NEMO (NF-κB essential modulator) component of the IKK complex and are required for TAK1 to activate IKKs, but not MAP kinases. An essential E3 ligase-independent role of TRAF6 is to recruit LUBAC into the MyD88 signalling complex, where it recognises preformed K63-Ub chains attached to protein components of these complexes, such as IRAK1 (IL-1 receptor-associated kinase), producing ubiquitin chains containing both types of linkage, termed K63/M1-Ub hybrids. The formation of K63/M1-Ub hybrids, which is a feature of several innate immune signalling pathways, permits the co-recruitment of proteins that interact with either K63-Ub or M1-Ub chains. Two likely roles for K63/M1-Ub hybrids are to facilitate the TAK1-dependent activation of the IKK complex and to prevent the hyperactivation of these kinases by recruiting A20 and A20-binding inhibitor of NF-κB1 (ABIN1). These proteins restrict activation of the TAK1 and IKK complexes, probably by competing with them for binding to K63/M1-Ub hybrids. The formation of K63/M1-Ub hybrids may also regulate the rate at which the ubiquitin linkages in these chains are hydrolysed. The IKK-catalysed phosphorylation of some of its substrates permits their recognition by the E3 ligase SCF βTRCP , leading to their Lys48-linked ubiquitylation and proteasomal degradation. Innate immune signalling is therefore controlled by the formation and destruction of three different types of ubiquitin linkage.

The role of hybrid ubiquitin chains in the MyD88 and other innate immune signalling pathways

PubMed Central

Cohen, Philip; Strickson, Sam

2017-01-01

The adaptor protein MyD88 is required for signal transmission by toll-like receptors and receptors of the interleukin-1 family of cytokines. MyD88 signalling triggers the formation of Lys63-linked and Met1-linked ubiquitin (K63-Ub, M1-Ub) chains within minutes. The K63-Ub chains, which are formed by the E3 ubiquitin ligases TRAF6, Pellino1 and Pellino2, activate TAK1, the master kinase that switches on mitogen-activated protein (MAP) kinase cascades and initiates activation of the canonical IκB kinase (IKK) complex. The M1-Ub chains, which are formed by the linear ubiquitin chain assembly complex (LUBAC), bind to the NEMO (NF-κB essential modulator) component of the IKK complex and are required for TAK1 to activate IKKs, but not MAP kinases. An essential E3 ligase-independent role of TRAF6 is to recruit LUBAC into the MyD88 signalling complex, where it recognises preformed K63-Ub chains attached to protein components of these complexes, such as IRAK1 (IL-1 receptor-associated kinase), producing ubiquitin chains containing both types of linkage, termed K63/M1-Ub hybrids. The formation of K63/M1-Ub hybrids, which is a feature of several innate immune signalling pathways, permits the co-recruitment of proteins that interact with either K63-Ub or M1-Ub chains. Two likely roles for K63/M1-Ub hybrids are to facilitate the TAK1-dependent activation of the IKK complex and to prevent the hyperactivation of these kinases by recruiting A20 and A20-binding inhibitor of NF-κB1 (ABIN1). These proteins restrict activation of the TAK1 and IKK complexes, probably by competing with them for binding to K63/M1-Ub hybrids. The formation of K63/M1-Ub hybrids may also regulate the rate at which the ubiquitin linkages in these chains are hydrolysed. The IKK-catalysed phosphorylation of some of its substrates permits their recognition by the E3 ligase SCFβTRCP, leading to their Lys48-linked ubiquitylation and proteasomal degradation. Innate immune signalling is therefore controlled by the formation and destruction of three different types of ubiquitin linkage. PMID:28475177

Supramolecular Organization of the α121-α565 Collagen IV Network*

PubMed Central

Robertson, Wesley E.; Rose, Kristie L.; Hudson, Billy G.; Vanacore, Roberto M.

2014-01-01

Collagen IV is a family of 6 chains (α1-α6), that form triple-helical protomers that assemble into supramolecular networks. Two distinct networks with chain compositions of α121 and α345 have been established. These oligomerize into separate α121 and α345 networks by a homotypic interaction through their trimeric noncollagenous (NC1) domains, forming α121 and α345 NC1 hexamers, respectively. These are stabilized by novel sulfilimine (SN) cross-links, a covalent cross-link that forms between Met93 and Hyl211 at the trimer-trimer interface. A third network with a composition of α1256 has been proposed, but its supramolecular organization has not been established. In this study we investigated the supramolecular organization of this network by determining the chain identity of sulfilimine-cross-linked NC1 domains derived from the α1256 NC1 hexamer. High resolution mass spectrometry analyses of peptides revealed that sulfilimine bonds specifically cross-link α1 to α5 and α2 to α6 NC1 domains, thus providing the spatial orientation between interacting α121 and α565 trimers. Using this information, we constructed a three-dimensional homology model in which the α565 trimer shows a good chemical and structural complementarity to the α121 trimer. Our studies provide the first chemical evidence for an α565 protomer and its heterotypic interaction with the α121 protomer. Moreover, our findings, in conjunction with our previous studies, establish that the six collagen IV chains are organized into three canonical protomers α121, α345, and α565 forming three distinct networks: α121, α345, and α121-α565, each of which is stabilized by sulfilimine bonds between their C-terminal NC1 domains. PMID:25006246

Transfer of the α5(IV) Collagen Chain Gene to Smooth Muscle Restores in Vivo Expression of the α6(IV) Collagen Chain in a Canine Model of Alport Syndrome

PubMed Central

Harvey, Scott J.; Zheng, Keqin; Jefferson, Barbara; Moak, Peter; Sado, Yoshikazu; Naito, Ichiro; Ninomiya, Yoshifumi; Jacobs, Robert; Thorner, Paul S.

2003-01-01

X-linked Alport syndrome is a progressive renal disease caused by mutations in the COL4A5 gene, which encodes the α5(IV) collagen chain. As an initial step toward gene therapy for Alport syndrome, we report on the expression of recombinant α5(IV) collagen in vitro and in vivo. A full-length cDNA-encoding canine α5(IV) collagen was cloned and expressed in vitro by transfection of HEK293 cells that synthesize the α1(IV) and α2(IV), but not the α3(IV) to α6(IV) collagen chains. By Northern blotting, an α5(IV) mRNA transcript of 5.2 kb was expressed and the recombinant protein was detected by immunocytochemistry. The chain was secreted into the medium as a 190-kd monomer; no triple helical species were detected. Transfected cells synthesized an extracellular matrix containing the α1(IV) and α2(IV) chains but the recombinant α5(IV) chain was not incorporated. These findings are consistent with the concept that the α5(IV) chain requires one or more of the α3(IV), α4(IV), or α6(IV) chains for triple helical assembly. In vivo studies were performed in dogs with X-linked Alport syndrome. An adenoviral vector containing the α5(IV) transgene was injected into bladder smooth muscle that lacks both the α5(IV) and α6(IV) chains in these animals. At 5 weeks after injection, there was expression of both the α5(IV) and α6(IV) chains by smooth muscle cells at the injection site in a basement membrane distribution. Thus, this recombinant α5(IV) chain is capable of restoring expression of a second α(IV) chain that requires the presence of the α5(IV) chain for incorporation into collagen trimers. This vector will serve as a useful tool to further explore gene therapy for Alport syndrome. PMID:12598321

High thermal stability and antiferromagnetic properties of a 3D Mn(II)-organic framework with metal carboxylate chains

NASA Astrophysics Data System (ADS)

Han, Lei; Zhou, Yan; Wang, Xiu-Teng; Li, Xing; Tong, Ming-Liang

2009-04-01

A novel three-dimensional metal-organic framework, [Mn 2(hfipbb) 2(bpy)] n ( 1) (H 2hfipbb = 4,4'-(hexafluoroisopropylidene)bis(benzoic acid), bpy = 4,4'-bipyridine), has been hydrothermally synthesized and structurally characterized. The complex consists of metal carboxylate chains, which are cross-linked to six adjacent chains through organic moieties forming extended three-dimensional networks. Complex 1 exhibits high thermal stability (450 °C) and antiferromagnetic properties.

C4I: Weapon or Achilles’ Heel

DTIC Science & Technology

1994-06-17

LINK? .......... .. 19 The People ...... ............... .. 19 The Impact .......... ............ .. 21 V WHAT DOES IT ALL MEAN ? ... ......... .. 23...people who will serve as the key link in the chain needed to pull the system together. 22 CHAPTER V WHAT DOES IT ALL MEAN ? Conclusions. As the military

In Praise of the Catenary

ERIC Educational Resources Information Center

Behroozi, F.

2018-01-01

When a chain hangs loosely from its end points, it takes the familiar form known as the catenary. Power lines, clothes lines, and chain links are familiar examples of the catenary in everyday life. Nevertheless, the subject is conspicuously absent from current introductory physics and calculus courses. Even in upper-level physics and math courses,…

Teaching Children with Autism to Request Help with Difficult Tasks

ERIC Educational Resources Information Center

Rodriguez, Nicole M.; Levesque, Megan A.; Cohrs, Victoria L.; Niemeier, Jessica J.

2017-01-01

We taught three children diagnosed with autism spectrum disorder to request help using an interrupted chain procedure during which we manipulated task materials such that the child was either incapable or capable of independently completing a link of a behavior chain. We initially observed undesirable generalization of requests for help during…

Web Supplement to "Teaching Chain-Weight Real GDP Measures."

ERIC Educational Resources Information Center

Cahill, Miles B.

2003-01-01

Describes a Web site that is a companion to the Miles Cahill article, "Teaching Chain-Weight Real GDP Measures." States that the exercises are useful because intermediate level textbooks treat this topic casually. Indicates that the Web site contains the comment tool, an overview of the concepts, and links to article references. (JEH)

Psychological Distance to Reward: Effects of S+ Duration and the Delay Reduction It Signals

ERIC Educational Resources Information Center

Alessandri, Jerome; Stolarz-Fantino, Stephanie; Fantino, Edmund

2011-01-01

A concurrent-chains procedure was used to examine choice between segmented (two-component chained schedules) and unsegmented schedules (simple schedules) in terminal links with equal inter-reinforcement intervals. Previous studies using this kind of experimental procedure showed preference for unsegmented schedules for both pigeons and humans. In…

Structural insight into SUMO chain recognition and manipulation by the ubiquitin ligase RNF4

PubMed Central

Xu, Yingqi; Plechanovová, Anna; Simpson, Peter; Marchant, Jan; Leidecker, Orsolya; Kraatz, Sebastian; Hay, Ronald T.; Matthews, Steve J.

2014-01-01

The small ubiquitin-like modifier (SUMO) can form polymeric chains that are important signals in cellular processes such as meiosis, genome maintenance and stress response. The SUMO-targeted ubiquitin ligase RNF4 engages with SUMO chains on linked substrates and catalyses their ubiquitination, which targets substrates for proteasomal degradation. Here we use a segmental labelling approach combined with solution nuclear magnetic resonance (NMR) spectroscopy and biochemical characterization to reveal how RNF4 manipulates the conformation of the SUMO chain, thereby facilitating optimal delivery of the distal SUMO domain for ubiquitin transfer. PMID:24969970

Crystal structure of 4-meth-oxy-N-(piperidine-1-carbono-thio-yl)benzamide.

PubMed

Suhud, Khairi; Hasbullah, Siti Aishah; Ahmad, Musa; Heng, Lee Yook; Kassim, Mohammad B

2017-10-01

In the title compound, C 14 H 18 N 2 O 2 S, the piperidine ring has a chair conformation. Its mean plane is twisted with respect to the 4-meth-oxy-benzoyl ring, with a dihedral angle of 63.0 (3)°. The central N-C(=S)-N(H)-C(=O) bridge is twisted with an N-C-N-C torsion angle of 74.8 (6)°. In the crystal, mol-ecules are linked by N-H⋯O and C-H⋯O hydrogen bonds, forming chains along the c -axis direction. Adjacent chains are linked by C-H⋯π inter-actions, forming layers parallel to the ac plane. The layers are linked by offset π-π inter-actions [inter-centroid distance = 3.927 (3) Å], forming a supra-molecular three-dimensional structure.

New Aptes Cross-linked Polymers from Poly(ethylene oxide)s and Cyanuric Chloride for Lithium Batteries

NASA Technical Reports Server (NTRS)

Tigelaar, Dean M.; Meador, Mary Ann B.; Kinder, James D.; Bennett, William R.

2005-01-01

A new series of polymer electrolytes for use as membranes for lithium batteries are described. Electrolytes were made by polymerization between cyanuric chloride and diamino-terminated poly(ethylene oxide)s, followed by cross-linking via a sol-gel process. Thermal analysis and lithium conductivity of freestanding polymer films were studied. The effects of several variables on conductivity were investigated, such as length of backbone PEO chain, length of branching PEO chain, extent of branching, extent of cross-linking, salt content, and salt counterion. Polymer films with the highest percentage of PEO were found to be the most conductive, with a maximum lithium conductivity of 3.9 x 10(exp -5) S/cm at 25 C. Addition of plasticizer to the dry polymers increased conductivity by an order of magnitude.

Let there be light: photo-cross-linked block copolymer nanoparticles.

PubMed

Roy, Debashish; Sumerlin, Brent S

2014-01-01

Polymeric nanoparticles are prepared by selectively cross-linking a photo-sensitive dimethylmaleimide-containing block of a diblock copolymer via UV irradiation. A well-defined photo-cross-linkable block copolymer is prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization of a dimethylmaleimide-functional acrylamido monomer containing photoreactive pendant groups with a poly(N,N-dimethylacrylamide) (PDMA) macro-chain transfer agent. The resulting amphiphilic block copolymers form micelles in water with a hydrophilic PDMA shell and a hydrophobic photo-cross-linkable dimethylmaleimide-containing core. UV irradiation results in photodimerization of the dimethylmaleimide groups within the micelle cores to yield core-cross-linked aggregates. Alternatively, UV irradiation of homogeneous solutions of the block copolymer in a non-selective solvent leads to in situ nanoparticle formation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The core structure of ginsenan PA, a phagocytosis-activating polysaccharide from the root of Panax ginseng.

PubMed

Tomoda, M; Hirabayashi, K; Shimizu, N; Gonda, R; Ohara, N

1994-09-01

Controlled Smith degradation and limited hydrolysis of ginsenan PA, the main phagocytosis-activating polysaccharide isolated from the root of Panax ginseng C. A. Meyer, were performed. The reticuloendothelial system-potentiating and anti-complementary activities of the degradation products were investigated. Methylation analysis of the primary and secondary Smith degradation products indicated that the core structural features of ginsenan PA include a backbone chain mainly composed of beta-1,3-linked D-galactose. Almost half of the galactose units in the backbone carry side-chains composed of beta-1,6-linked D-galactosyl residues at position 6. Further 3,6-branching of D-galactose units was observed in a part of the side-chains. alpha-L-Arabinose units are connected mainly to the core galactose moieties via position 6. Removal of most of the arabinose units had a considerable effect on immunological activity.

Structural Characteristics and Anticancer Activity of Fucoidan from the Brown Alga Sargassum mcclurei

PubMed Central

Duc Thinh, Pham; Menshova, Roza V.; Ermakova, Svetlana P.; Anastyuk, Stanislav D.; Ly, Bui Minh; Zvyagintseva, Tatiana N.

2013-01-01

Three different fucoidan fractions were isolated and purified from the brown alga, Sargassum mcclurei. The SmF1 and SmF2 fucoidans are sulfated heteropolysaccharides that contain fucose, galactose, mannose, xylose and glucose. The SmF3 fucoidan is highly sulfated (35%) galactofucan, and the main chain of the polysaccharide contains a →3)-α-l-Fucp(2,4SO3−)-(1→3)-α-l-Fucp(2,4SO3−)-(1→ motif with 1,4-linked 3-sulfated α-l-Fucp inserts and 6-linked galactose on reducing end. Possible branching points include the 1,2,6- or 1,3,6-linked galactose and/or 1,3,4-linked fucose residues that could be glycosylated with terminal β-d-Galp residues or chains of alternating sulfated 1,3-linked α-l-Fucp and 1,4-linked β-d-Galp residues, which have been identified in galactofucans for the first time. Both α-l-Fucp and β-d-Galp residues are sulfated at C-2 and/or C-4 (and some C-6 of β-d-Galp) and potentially the C-3 of terminal β-d-Galp, 1,4-linked β-d-Galp and 1,4-linked α-l-Fucp residues. All fucoidans fractions were less cytotoxic and displayed colony formation inhibition in colon cancer DLD-1 cells. Therefore, these fucoidan fractions are potential antitumor agents. PMID:23648551

Supply chain management for small business--how to avoid being part of the food chain.

PubMed

Knechtges, J P; Watts, C A

2000-08-01

A supply chain is a series of customer and supplier relationships that extend throughout and beyond the company. It is an interwoven set of links that together form a chain supplying our customers in a seamless and integrated fashion delivering a high level of customer satisfaction. Supply chain management (SCM) integrates all activities so they are focused on customer satisfaction (both internally and externally). One of the things this article will attempt to accomplish is to provide a clear understanding of SCM's positive impact on customer service as well as on improving profitability, cash flow, product cycle times, and communication. Whether we go forward in the supply chain to the final end-user or backward in the supply chain to our supplier's suppliers, SCM will significantly improve our ability to serve our customers.

Evolutionary Game Model Study of Construction Green Supply Chain Management under the Government Intervention

NASA Astrophysics Data System (ADS)

Xing, Yuanzhi; Deng, Xiaoyi

2017-11-01

The paper first has defined the concepts of green supply chain management and evolution game theory, and pointed out the characteristics of green supply chain management in construction. The main participants and key links of the construction green supply chain management are determined by constructing the organization framework. This paper established the evolutionary game model between construction enterprises and recycling enterprises for the green supply chain closed-loop structure. The waste recycling evolutionary stability equilibrium solution is obtained to explore the principle and effective scope of government policy intervention. This paper put forward the relevant countermeasures to the green supply chain management in construction recycling stage from the government point of view. The conclusion has reference value and guidance to the final product construction enterprises, recycling enterprises and the government during green supply chain.

Single chain technology: Toward the controlled synthesis of polymer nanostructures

NASA Astrophysics Data System (ADS)

Lyon, Christopher

A technique for fabricating advanced polymer nanostructures enjoying recent popularity is the collapse or folding of single polymer chains in highly dilute solution mediated by intramolecular cross-linking. We term the resultant structures single-chain nanoparticles (SCNP). This technique has proven particularly valuable in the synthesis of nanomaterials on the order of 5 -- 20 nm. Many different types of covalent and non-covalent chemistries have been used to this end. This dissertation investigates the use of so-called single-chain technology to synthesize nanoparticles using modular techniques that allow for easy incorporation of functionality or special structural or characteristic features. Specifically, the synthesis of linear polymers functionalized with pendant monomer units and the subsequent intramolecular polymerization of these monomer units is discussed. In chapter 2, the synthesis of SCNP using alternating radical polymerization is described. Polymers functionalized with pendant styrene and stilbene groups are synthesized via a modular post-polymerization Wittig reaction. These polymers were exposed to radical initiators in the presence (and absence) of maleic anhydride and other electron deficient monomers in order to form intramolecular cross-links. Chapter 3 discusses templated acyclic diene metathesis (ADMET) polymerization using single-chain technology, starting with the controlled ring-opening polymerization of a glycidyl ether functionalized with an ADMET monomer. This polymer was then exposed to Grubbs' catalyst to polymerize the ADMET monomer units. The ADMET polymer was hydrolytically cleaved from the template and separated. Upon characterization, it was found that the daughter ADMET polymer had a similar degree of polymerization, but did not retain the low dispersity of the template. Chapter 4 details the synthesis of aldehyde- and diol-functionalized polymers toward the synthesis of SCNP containing dynamic, acid-degradable acetal cross-links. SCNP fabrication with these materials is beyond the scope of this dissertation.

Crystal structure of methyl (4R)-4-(4-meth-oxy-benzo-yl)-4-{[(1R)-1-phenyl-eth-yl]carbamo-yl}butano-ate.

PubMed

Manchado, Alejandro; Salgado, Mateo M; Vicente, Álvaro; Díez, David; Sanz, Francisca; Garrido, Narciso M

2017-04-01

The title compound, C 22 H 25 NO 5 , was prepared by CAN [cerium(IV) ammonium nitrate] oxidation of the corresponding β-lactam. The dihedral angle between the benzene rings is 13.3 (4)° and the C-N-C(=O)-C torsion angle is 176.1 (6)°. In the crystal, amide- C (4) N-H⋯O and reinforcing C-H⋯O hydrogen bonds link the mol-ecules into infinite [010] chains. Further C-H⋯O hydrogen bonds cross-link the chains in the c -axis direction.

Crystal structure of 1-meth-oxy-2,2,2-tris-(pyrazol-1-yl)ethane.

PubMed

Lyubartseva, Ganna; Parkin, Sean; Coleman, Morgan D; Mallik, Uma Prasad

2014-09-01

The title compound, C12H14N6O, consists of three pyrazole rings bound via nitro-gen to the distal ethane carbon of meth-oxy ethane. The dihedral angles between the three pyrazole rings are 67.62 (14), 73.74 (14), and 78.92 (12)°. In the crystal, mol-ecules are linked by bifurcated C-H,H⋯N hydrogen bonds, forming double-stranded chains along [001]. The chains are linked via C-H⋯O hydrogen bonds, forming a three-dimensional framework structure. The crystal was refined as a perfect (0.5:0.5) inversion twin.

Benzil bis­(ketazine)

PubMed Central

Patra, Goutam Kumar; Mukherjee, Anindita; Ng, Seik Weng

2009-01-01

The title compound (systematic name: 1,1′,2,2′-tetra­phenyl-2,2′-azinodiethanone), C28H20N2O2, was obtained by the reaction of benzil monohydrazone with chromium(III) nitrate. The dibenzyl­idene hydrazine unit is nearly planar (r.m.s. deviation = 0.073 Å) and the two benzoyl units are oriented almost perpendicular to it [dihedral angle = 87.81 (2), 87.81 (2)°]. The mol­ecules are linked into chains along the c axis by C—H⋯O hydrogen bonds and the chains are cross-linked via C—H⋯π inter­actions involving the benzoyl phenyl rings. PMID:21583456

Nacre-mimetic clay/xyloglucan bionanocomposites: a chemical modification route for hygromechanical performance at high humidity.

PubMed

Kochumalayil, Joby J; Morimune, Seira; Nishino, Takashi; Ikkala, Olli; Walther, Andreas; Berglund, Lars A

2013-11-11

Nacre-mimetic bionanocomposites of high montmorillonite (MTM) clay content, prepared from hydrocolloidal suspensions, suffer from reduced strength and stiffness at high relative humidity. We address this problem by chemical modification of xyloglucan in (XG)/MTM nacre-mimetic nanocomposites, by subjecting the XG to regioselective periodate oxidation of side chains to enable it to form covalent cross-links to hydroxyl groups in neighboring XG chains or to the MTM surface. The resulting materials are analyzed by FTIR spectroscopy, thermogravimetric analysis, carbohydrate analysis, calorimetry, X-ray diffraction, scanning electron microscopy, tensile tests, and oxygen barrier properties. We compare the resulting mechanical properties at low and high relative humidity. The periodate oxidation leads to a strong increase in modulus and strength of the materials. A modulus of 30 GPa for cross-linked composite at 50% relative humidity compared with 13.7 GPa for neat XG/MTM demonstrates that periodate oxidation of the XG side chains leads to crucially improved stress transfer at the XG/MTM interface, possibly through covalent bond formation. This enhanced interfacial adhesion and internal cross-linking of the matrix moreover preserves the mechanical properties at high humidity condition and leads to a Young's modulus of 21 GPa at 90%RH.

Ubiquitin Linkage-Specific Affimers Reveal Insights into K6-Linked Ubiquitin Signaling.

PubMed

Michel, Martin A; Swatek, Kirby N; Hospenthal, Manuela K; Komander, David

2017-10-05

Several ubiquitin chain types have remained unstudied, mainly because tools and techniques to detect these posttranslational modifications are scarce. Linkage-specific antibodies have shaped our understanding of the roles and dynamics of polyubiquitin signals but are available for only five out of eight linkage types. We here characterize K6- and K33-linkage-specific "affimer" reagents as high-affinity ubiquitin interactors. Crystal structures of affimers bound to their cognate chain types reveal mechanisms of specificity and a K11 cross-reactivity in the K33 affimer. Structure-guided improvements yield superior affinity reagents suitable for western blotting, confocal fluorescence microscopy and pull-down applications. This allowed us to identify RNF144A and RNF144B as E3 ligases that assemble K6-, K11-, and K48-linked polyubiquitin in vitro. A protocol to enrich K6-ubiquitinated proteins from cells identifies HUWE1 as a main E3 ligase for this chain type, and we show that mitofusin-2 is modified with K6-linked polyubiquitin in a HUWE1-dependent manner. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Structural Basis for the Ubiquitin-Linkage Specificity and deISGylating Activity of SARS-CoV Papain-Like Protease

PubMed Central

Ratia, Kiira; Kilianski, Andrew; Baez-Santos, Yahira M.; Baker, Susan C.; Mesecar, Andrew

2014-01-01

Severe acute respiratory syndrome coronavirus (SARS-CoV) encodes a papain-like protease (PLpro) with both deubiquitinating (DUB) and deISGylating activities that are proposed to counteract the post-translational modification of signaling molecules that activate the innate immune response. Here we examine the structural basis for PLpro's ubiquitin chain and interferon stimulated gene 15 (ISG15) specificity. We present the X-ray crystal structure of PLpro in complex with ubiquitin-aldehyde and model the interaction of PLpro with other ubiquitin-chain and ISG15 substrates. We show that PLpro greatly prefers K48- to K63-linked ubiquitin chains, and ISG15-based substrates to those that are mono-ubiquitinated. We propose that PLpro's higher affinity for K48-linked ubiquitin chains and ISG15 stems from a bivalent mechanism of binding, where two ubiquitin-like domains prefer to bind in the palm domain of PLpro with the most distal ubiquitin domain interacting with a “ridge” region of the thumb domain. Mutagenesis of residues within this ridge region revealed that these mutants retain viral protease activity and the ability to catalyze hydrolysis of mono-ubiquitin. However, a select number of these mutants have a significantly reduced ability to hydrolyze the substrate ISG15-AMC, or be inhibited by K48-linked diubuiquitin. For these latter residues, we found that PLpro antagonism of the nuclear factor kappa-light-chain-enhancer of activated B-cells (NFκB) signaling pathway is abrogated. This identification of key and unique sites in PLpro required for recognition and processing of diubiquitin and ISG15 versus mono-ubiquitin and protease activity provides new insight into ubiquitin-chain and ISG15 recognition and highlights a role for PLpro DUB and deISGylase activity in antagonism of the innate immune response. PMID:24854014

Targeting radiosensitizers to DNA by attachment of an intercalating group: Nitroimidazole-linked phenanthridines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cowan, D.S.; Panicucci, R.; McClelland, R.A.

The nitroimidazole-linked phenanthridine series of compounds (NLP-1, 2, and 3) were synthesized under the assumption that it should be possible to enhance the molar efficiency of 2-nitroimidazoles as hypoxic cell radiosensitizers and cytotoxins by targeting them to their likely site of action, DNA. The targeting group chosen was the phenanthridine moiety, the major component of the classical DNA intercalating compound, ethidium bromide. The sole difference between the compounds is the length of the hydrocarbon chain linking the nitroimidazole to the phenanthridine. The phenanthridine group with a three-carbon side chain, P-1, was also synthesized to allow studies on the effect ofmore » the targeting group by itself. The ability of the compounds to bind to DNA is inversely proportional to their linker chain length with binding constant values ranging from approximately 1 {times} 10(5) mol-1 for NLP-2 to 6 {times} 10(5) mol-1 for NLP-3. The NLP compounds show selective toxicity to hypoxic cells at 37 degrees C at external drug concentrations 10-40 times lower than would be required for untargeted 2-nitroimidazoles such as misonidazole in vitro. Toxicity to both hypoxic and aerobic cells is dependent on the linker chain: the shorter the chain, the greater the toxicity. In addition, the NLP compounds radiosensitize hypoxic cells at external drug concentrations as low as 0.05 mM with almost the full oxygen effect being observed at a concentration of 0.5 mM. These concentrations are 10-100 times lower than would be required for similar radiosensitization using misonidazole. Radiosensitizing ability is independent of linker chain length. The present compounds represent prototypes for further studies of the efficacy and mechanism of action of 2-nitroimidazoles targeted to DNA by linkage to an intercalating group.« less

Engineering of Saccharomyces cerevisiae for the synthesis of short chain fatty acids.

PubMed

Leber, Christopher; Da Silva, Nancy A

2014-02-01

Carbon feedstocks from fossilized sources are being rapidly depleted due to rising demand for industrial and commercial applications. Many petroleum-derived chemicals can be directly or functionally substituted with chemicals derived from renewable feedstocks. Several short chain organic acids may fulfill this role using their functional groups as a target for chemical catalysis. Saccharomyces cerevisiae was engineered to produce short chain carboxylic acids (C6 to C10 ) from glucose using the heterologous Homo sapiens type I fatty acid synthase (hFAS). This synthase was activated by phosphopantetheine transfereases AcpS and Sfp from Escherichia coli and Bacillus subtilis, respectively, both in vitro and in vivo. hFAS was produced in the holo-form and produced carboxylic acids in vitro, confirmed by NADPH and ADIFAB assays. Overexpression of hFAS in a yeast FAS2 knockout strain, deficient in de novo fatty acid synthesis, demonstrated the full functional replacement of the native fungal FAS by hFAS. Two active heterologous short chain thioesterases (TEs) from Cuphea palustris (CpFatB1) and Rattus norvegicus (TEII) were evaluated for short chain fatty acid (SCFA) synthesis in vitro and in vivo. Three hFAS mutants were constructed: a mutant deficient in the native TE domain, a mutant with a linked CpFatB1 TE and a mutant with a linked TEII TE. Using the native yeast fatty acid synthase for growth, the overexpression of the hFAS mutants and the short-chain TEs (linked or plasmid-based) increased in vivo caprylic acid and total SCFA production up to 64-fold (63 mg/L) and 52-fold (68 mg/L), respectively, over the native yeast levels. Combined over-expression of the phosphopantetheine transferase with the hFAS mutant resulted in C8 titers of up to 82 mg/L and total SCFA titers of up to 111 mg/L. © 2013 Wiley Periodicals, Inc.

Schizophyllan polysaccharide as potential biopolymer ingredient in lubrication

USDA-ARS?s Scientific Manuscript database

Schizophyllan is a homoglucan produced by the fungus Schizophyllum commune, with a ß-1,3-linked backbone and ß-1,6-linked side chains of single glucose units at every other residue. Schizophyllan is commercially produced for a variety of applications including in pharmaceutical and cosmetics formula...

Relationship between sugar chain structure and biological activity of recombinant human erythropoietin produced in Chinese hamster ovary cells.

PubMed Central

Takeuchi, M; Inoue, N; Strickland, T W; Kubota, M; Wada, M; Shimizu, R; Hoshi, S; Kozutsumi, H; Takasaki, S; Kobata, A

1989-01-01

Two forms of erythropoietin, EPO-bi and EPO-tetra, with different biological activities were isolated from the culture medium of a recombinant Chinese hamster ovary cell line, B8-300, into which the human erythropoietin gene had been introduced. EPO-bi, an unusual form, showed only one-seventh the in vivo activity and 3 times higher in vitro activity of the previously described recombinant human EPO (standard EPO). In contrast, EPO-tetra showed both in vivo and in vitro activities comparable to those of the standard EPO. EPO-bi, EPO-tetra, and the standard EPO had the same amino acid composition and immunoreactivity. However, structural analyses of their N-linked sugar chains revealed that EPO-bi contains the biantennary complex type as the major sugar chain, while EPO-tetra and the standard EPO contain the tetraantennary complex type as the major sugar chain. From examination of various preparations of recombinant human EPO, we found a positive correlation between the in vivo activity of EPO and the ratio of tetraantennary to biantennary oligosaccharides. These results suggest that higher branching of the N-linked sugar chains is essential for effective expression of in vivo biological activity of EPO. PMID:2813359

Selected Aspects Of The Risk In The Supply Chain In Context Of The Supplier Quality Management

NASA Astrophysics Data System (ADS)

Koblen, Ivan; Lestyánszka Škůrková, Katarína

2015-06-01

The introductory part of the paper underlines the importance of "Risk-based thinking" in the Quality Management System (QMS) and risk in the supply chain, as a principle part of the QMS. After introducing the key terms, the authors focused on the principle part of the article - explanation of the external and internal supply chain risks and the main factors concerning the supply risks, demand risks and environmental risks (as cardinal types of external supply chain risks) as well as the manufacturing and process risks, network/planning and control risks (as most important types of internal supply chain risks). The authors inform on the selected supply chain risk management tools, especially on those which are linked to the appropriate utilization of quality management tools.

Transition records of stationary Markov chains.

PubMed

Naudts, Jan; Van der Straeten, Erik

2006-10-01

In any Markov chain with finite state space the distribution of transition records always belongs to the exponential family. This observation is used to prove a fluctuation theorem, and to show that the dynamical entropy of a stationary Markov chain is linear in the number of steps. Three applications are discussed. A known result about entropy production is reproduced. A thermodynamic relation is derived for equilibrium systems with Metropolis dynamics. Finally, a link is made with recent results concerning a one-dimensional polymer model.

Buffering effect in continuous chains of unidirectionally coupled generators

NASA Astrophysics Data System (ADS)

Glyzin, S. D.; Kolesov, A. Yu.; Rozov, N. Kh.

2014-11-01

We propose a mathematical model of a continuous annular chain of unidirectionally coupled generators given by some nonlinear advection-type hyperbolic boundary value problem. Such problems are constructed by a limit transition from annular chains of unidirectionally coupled ordinary differential equations with an unbounded increase in the number of links. We find that a certain buffering phenomenon is realized in our boundary value problem. Namely, we show that any preassigned finite number of stable periodic motions of the traveling-wave type can coexist in the model.

Enhancing Electrophoretic Display Lifetime: Thiol-Polybutadiene Evaporation Barrier Property Response to Network Microstructure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Caitlyn Christian

An evaporation barrier is required to enhance the lifetime of electrophoretic deposition (EPD) displays. As EPD functions on the basis of reversible deposition and resuspension of colloids suspended in a solvent, evaporation of the solvent ultimately leads to device failure. Incorporation of a thiol-polybutadiene elastomer into EPD displays enabled display lifetime surpassing six months in counting and catalyzed rigid display transition into a flexible package. Final flexible display transition to mass production compels an electronic-ink approach to encapsulate display suspension within an elastomer shell. Final thiol-polybutadiene photosensitive resin network microstructure was idealized to be dense, homogeneous, and expose an elasticmore » response to deformation. Research at hand details an approach to understanding microstructural change within display elastomers. Polybutadiene-based resin properties are modified via polymer chain structure, with and without added aromatic urethane methacrylate difunctionality, and in measuring network response to variation in thiol and initiator concentration. Dynamic mechanical analysis results signify that cross-linked segments within a difunctionalized polybutadiene network were on average eight times more elastically active than that of linked segments within a non-functionalized polybutadiene network. Difunctionalized polybutadiene samples also showed a 2.5 times greater maximum elastic modulus than non-functionalized samples. Hybrid polymer composed of both polybutadiene chains encompassed TE-2000 stiffness and B-1000 elasticity for use in encapsulating display suspension. Later experiments measured kinetic and rheological response due to alteration in dithiol cross-linker chain length via real time Fourier transform infrared spectroscopy and real-time dynamic rheology. Distinct differences were discovered between dithiol resin systems, as maximum thiol conversion achieved in short and long chain length dithiols was 86% and 11%, respectively. Oscillatory real-time rheological experiments confirmed a more uniform network to better dissipate applied shear in short chain length dithiol systems, as long chain length dithiols relayed a steep internal stress build-up due to less cross-links and chain entanglements. Thorough understanding of network formation aids the production of a stronger and impermeable elastomeric barrier for preservation of EPD displays.« less

The 1:1 inclusion compounds zolmitriptan-benzene and zolmitriptan-phenol.

PubMed

Swamy, G Y S K; Sridhar, B; Ravikumar, K; Krishnan, Harihara

2007-07-01

In the benzene and phenol solvates of (S)-4-{3-[2-(dimethylamino)ethyl]-1H-indol-5-ylmethyl}oxazolidin-2-one, viz. C(16)H(21)N(3)O(2) x C(6)H(6), (I), and C(16)H(21)N(3)O(2) x C(6)H(5)OH, (II), the host molecule has three linked residues, namely a planar indole ring system, an ethylamine side chain and an oxazolidinone system. It has comparable features to that of sumatriptan, although the side-chain orientations of (I) and (II) differ from those of sumatriptan. Both (I) and (II) have host-guest-type structures. The host molecule in (I) and (II) has an L-shaped form, with the oxazolidinone ring occupying the base and the remainder of the molecule forming the upright section. In (I), each benzene guest molecule is surrounded by four host molecules, and these molecules are linked by a combination of N-H...N, N-H...O and C-H...O hydrogen bonds into chains of edge-fused R(4)(4)(33) rings. In (II), two independent molecules are present in the asymmetric unit, with similar conformations. The heterocyclic components are connected through N-H...N, N-H...O and C-H...O interactions to form chains of edge-fused R(6)(4)(38) rings, from which the phenol guest molecules are pendent, linked by O-H...O hydrogen bonds. The structures are further stabilized by extensive C-H...pi interactions.

Serial lectin affinity chromatography with concavalin A and wheat germ agglutinin demonstrates altered asparagine-linked sugar-chain structures of prostatic acid phosphatase in human prostate carcinoma.

PubMed

Yoshida, K I; Honda, M; Arai, K; Hosoya, Y; Moriguchi, H; Sumi, S; Ueda, Y; Kitahara, S

1997-08-01

Differences between human prostate carcinoma (PCA, five cases) and benign prostatic hyperplasia (BPH, five cases) in asparagine-linked (Asn) sugar-chain structure of prostatic acid phosphatase (PAP) were investigated using lectin affinity chromatography with concanavalin A (Con A) and wheat germ agglutinin (WGA). PAP activities were significantly decreased in PCA-derived PAP, while no significant differences between the two PAP preparations were observed in the enzymatic properties (Michaelis-Menten value, optimal pH, thermal stability, and inhibition study). In these PAP preparations, all activities were found only in the fractions which bound strongly to the Con A column and were undetectable in the Con A unbound fractions and in the fractions which bound weakly to the Con A column. The relative amounts of PAP which bound strongly to the Con A column but passed through the WGA column, were significantly greater in BPH-derived PAP than in PCA-derived PAP. In contrast, the relative amounts of PAP which bound strongly to the Con A column and bound to the WGA column, were significantly greater in PCA-derived PAP than in BPH-derived PAP. The findings suggest that Asn-linked sugar-chain structures are altered during oncogenesis in human prostate and also suggest that studies of qualitative differences of sugar-chain structures of PAP might lead to a useful diagnostic tool for PCA.

Corn fiber utilization for production of Schizophyllan

USDA-ARS?s Scientific Manuscript database

Corn fiber is an abundant coproduct of the corn wet milling process, primarily composed of the seed pericarp and adherent starch. Schizophyllan is a biopolymer composed entirely of glucose, with a ß-1,3-linked backbone and single ß-1,6-linked glucose side chains at every third residue, produced by t...

A new family of fluidic precursors for the self-templated synthesis of hierarchical nanoporous carbons

DOE PAGES

Fulvio, Pasquale F.; Hillesheim, Patrick C.; Oyola, Yatsandra; ...

2016-06-24

Hierarchical nanoporous nitrogen-doped carbons were prepared from task specific ionic liquids having a bis-imidazolium motif linked with various organic groups. While ethyl chains linking the imidazolium ions afford microporous-mesoporous carbons, long or aromatic groups resulted in microporous samples.

76 FR 15791 - National Poultry Improvement Plan and Auxiliary Provisions

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-22

... microhemagglutination inhibition test, the enzyme-linked immunosorbent assay (ELISA) test,\\3\\ a polymerase chain [[Page... samplings and/or culture of reactors. \\3\\ Procedures for the enzyme-linked immunosorbent assay (ELISA) test... Immunosorbent Assay (ELISA),'' Proceedings, 30th Western Poultry Disease Conference, pp. 63-66, March 1981...

Links in the Chain: Bringing Together Literacy and Science

ERIC Educational Resources Information Center

Taylor, Neil; Hansford, Diane; Rizk, Nadya; Taylor, Subhashni

2017-01-01

In Australia, the Federal Government and the Australian Academy of Science have developed a programme entitled "Primary Connections" (primaryconnections.org. au), aimed at supporting the teaching of science in the primary sector. The programme makes strong and explicit links between science and literacy through the use of word walls,…

Novel sources of ß-glucanase for the enzymatic degradation of schizophyllan

USDA-ARS?s Scientific Manuscript database

Schizophyllan is a homoglucan produced by the fungus Schizophyllum commune, with a ß-1,3-linked backbone and ß-1,6-linked side chains of single glucose units at every other residue. Schizophyllan is commercially produced for pharmaceutical and cosmetics uses. However, surprisingly little informati...

Utilization of agricultural biomass in the production of the biopolymer schizophyllan

USDA-ARS?s Scientific Manuscript database

Schizophyllan is a homoglucan produced by the fungus Schizophyllum commune, with a ß-1,3-linked backbone and ß-1,6-linked side chains of single glucose units at every other residue. Schizophyllan is commercially produced for pharmaceutical and cosmetics uses. However, the unique physical propertie...

A Decision Model for Steady-State Choice in Concurrent Chains

ERIC Educational Resources Information Center

Christensen, Darren R.; Grace, Randolph C.

2010-01-01

Grace and McLean (2006) proposed a decision model for acquisition of choice in concurrent chains which assumes that after reinforcement in a terminal link, subjects make a discrimination whether the preceding reinforcer delay was short or long relative to a criterion. Their model was subsequently extended by Christensen and Grace (2008, 2009a,…

From In-Session Behaviors to Drinking Outcomes: A Causal Chain for Motivational Interviewing

ERIC Educational Resources Information Center

Moyers, Theresa B.; Martin, Tim; Houck, Jon M.; Christopher, Paulette J.; Tonigan, J. Scott

2009-01-01

Client speech in favor of change within motivational interviewing sessions has been linked to treatment outcomes, but a causal chain has not yet been demonstrated. Using a sequential behavioral coding system for client speech, the authors found that, at both the session and utterance levels, specific therapist behaviors predict client change talk.…

Arabidopsis GUX Proteins Are Glucuronyltransferases Responsible for the Addition of Glucuronic Acid Side Chains onto Xylan

EPA Science Inventory

Xylan, the second most abundant cell wall polysaccharide, is composed of a linear backbone of β-(1,4)-linked xylosyl residues that are often substituted with sugar side chains, such as glucuronic acid (GlcA) and methylglucuronic acid (MeGlcA). It has recently been shown that muta...

The Chemical Chaperone, PBA, Reduces ER Stress and Autophagy and Increases Collagen IV α5 Expression in Cultured Fibroblasts From Men With X-Linked Alport Syndrome and Missense Mutations.

PubMed

Wang, Dongmao; Mohammad, Mardhiah; Wang, Yanyan; Tan, Rachel; Murray, Lydia S; Ricardo, Sharon; Dagher, Hayat; van Agtmael, Tom; Savige, Judy

2017-07-01

X-linked Alport syndrome (OMIM 301050) is caused by COL4A5 missense variants in 40% of families. This study examined the effects of chemical chaperone treatment (sodium 4-phenylbutyrate) on fibroblast cell lines derived from men with missense mutations. Dermal fibroblast cultures were established from 2 affected men and 3 normals. Proliferation rates were examined, the collagen IV α5 chain localized with immunostaining, and levels of the intra- and extracellular chains quantitated with an in-house enzyme-linked immunosorbent assay. COL4A5 mRNA was measured using quantitative reverse transcriptase polymerase chain reaction. Endoplasmic reticulum (ER) size was measured on electron micrographs and after HSP47 immunostaining. Markers of ER stress (ATF6, HSPA5, DDIT3), autophagy (ATG5, BECN1, ATG7), and apoptosis (CASP3, BAD, BCL 2 ) were also quantitated by quantitative reverse transcriptase polymerase chain reaction. Measurements were repeated after 48 hours of incubation with 10 mM sodium 4-phenylbutyrate acid. Both COL4A5 missense variants were associated with reduced proliferation rates on day 6 ( P  = 0.01 and P  = 0.03), ER enlargement, and increased mRNA for ER stress and autophagy (all P values < 0.05) when compared with normal. Sodium 4-phenylbutyrate treatment increased COL4A5 transcript levels ( P  < 0.01), and reduced ER size ( P  < 0.01 by EM and P  < 0.001 by immunostaining), ER stress (p HSPA5 and DDIT3, all P values < 0.01) and autophagy (ATG7, P  < 0.01). Extracellular collagen IV α5 chain was increased in the M1 line only ( P  = 0.06). Sodium 4-phenylbutyrate increases collagen IV α5 mRNA levels, reduces ER stress and autophagy, and possibly facilitates collagen IV α5 extracellular transport. Whether these actions delay end-stage renal failure in men with X-linked Alport syndrome and missense mutations will only be determined with clinical trials.

Antithrombogenic Polymer Coating.

DOEpatents

Huang, Zhi Heng; McDonald, William F.; Wright, Stacy C.; Taylor, Andrew C.

2003-01-21

An article having a non-thrombogenic surface and a process for making the article are disclosed. The article is formed by (i) coating a polymeric substrate with a crosslinked chemical combination of a polymer having at least two amino substituted side chains, a crosslinking agent containing at least two crosslinking functional groups which react with amino groups on the polymer, and a linking agent containing a first functional group which reacts with a third functional group of the crosslinking agent, and (ii) contacting the coating on the substrate with an antithrombogenic agent which covalently bonds to a second functional group of the linking agent. In one example embodiment, the polymer is a polyamide having amino substituted alkyl chains on one side of the polyamide backbone, the crosslinking agent is a phosphine having the general formula (A).sub.3 P wherein A is hydroxyalkyl, the linking agent is a polyhydrazide and the antithrombogenic agent is heparin.

Crystal structure of 4-meth­oxy-N-(piperidine-1-carbono­thio­yl)benzamide

PubMed Central

Suhud, Khairi; Hasbullah, Siti Aishah; Ahmad, Musa; Heng, Lee Yook

2017-01-01

In the title compound, C14H18N2O2S, the piperidine ring has a chair conformation. Its mean plane is twisted with respect to the 4-meth­oxy­benzoyl ring, with a dihedral angle of 63.0 (3)°. The central N—C(=S)—N(H)—C(=O) bridge is twisted with an N—C—N—C torsion angle of 74.8 (6)°. In the crystal, mol­ecules are linked by N—H⋯O and C—H⋯O hydrogen bonds, forming chains along the c-axis direction. Adjacent chains are linked by C—H⋯π inter­actions, forming layers parallel to the ac plane. The layers are linked by offset π–π inter­actions [inter­centroid distance = 3.927 (3) Å], forming a supra­molecular three-dimensional structure. PMID:29250374

Real time markerless motion tracking using linked kinematic chains

DOEpatents

Luck, Jason P [Arvada, CO; Small, Daniel E [Albuquerque, NM

2007-08-14

A markerless method is described for tracking the motion of subjects in a three dimensional environment using a model based on linked kinematic chains. The invention is suitable for tracking robotic, animal or human subjects in real-time using a single computer with inexpensive video equipment, and does not require the use of markers or specialized clothing. A simple model of rigid linked segments is constructed of the subject and tracked using three dimensional volumetric data collected by a multiple camera video imaging system. A physics based method is then used to compute forces to align the model with subsequent volumetric data sets in real-time. The method is able to handle occlusion of segments and accommodates joint limits, velocity constraints, and collision constraints and provides for error recovery. The method further provides for elimination of singularities in Jacobian based calculations, which has been problematic in alternative methods.

Structural characterization of a glucuronoarabinoxylan from pineapple (Ananas comosus (L.) Merrill) gum exudate.

PubMed

Simas-Tosin, Fernanda F; de Souza, Lauro M; Wagner, Ricardo; Pereira, Graciele C Z; Barraza, Ruth R; Wendel, Cinthia F; Sassaki, Guilherme L; Iacomini, Marcello; Gorin, Philip A J

2013-04-15

Native polysaccharide from pineapple gum (PANP) was obtained following alkaline extraction of gum and fractionation with cetylpyridinium chloride. It was characterized as a glucuronoarabinoxylan using NMR, methylation data, controlled Smith degradation, carboxy-reduction, and ESI-MS of oligosaccharides produced on mild acid hydrolysis of PANP. HSPEC-MALLS-RI of carboxy-reduced fraction showed homogeneous profile (Mw 1.943×10(5) g/mol). PANP was composed of Ara, Xyl, Gal, and GlcpA (40:23:7:30 molar ratio). Its main chain presented (1→4)-linked β-xylan, highly substituted at O-2 and O-3 by side chains of 3-O- and 3,5-di-O-linked α-Araf, 2-O- and 4-O-linked α-GlcpA, and nonreducing end-units of α-Araf, β-Arap, β-Galp, and α-GlcpA. ESI-MS of a mixture of oligosaccharides formed on the mild acid hydrolysis of PANP was consistent with repetitive structures of α-GlcpA O-3 linked at β-Xylp units, whereas in others glucuronoarabinoxylan-type gum exudates, α-GlcpA units had been previously found to be linked at O-2. Copyright © 2013 Elsevier Ltd. All rights reserved.

Conflict minerals from the Democratic Republic of the Congo: global tungsten processing plants, a critical part of the tungsten supply chain

USGS Publications Warehouse

Bermúdez-Lugo, Omayra

2014-01-01

The U.S. Geological Survey (USGS) analyzes supply chains to identify and define major components of mineral and material flows from ore extraction, through intermediate forms, to a final product. Two major reasons necessitate these analyses: (1) to identify risks associated with the supply of critical and strategic minerals to the United States and (2) to provide greater supply chain transparency so that policymakers have the information necessary to ensure domestic legislation compliance. This fact sheet focuses on the latter. The USGS National Minerals Information Center has been asked by governmental and non-governmental organizations to provide information on tin, tantalum, tungsten, and gold (collectively known as “3TG minerals”) processing facilities worldwide in response to U.S. legislation aimed at removing the link between the trade in these minerals and civil unrest in the Democratic Republic of the Congo. Post beneficiation processing plants (smelters and refineries) of 3TG mineral ores and concentrates were identified by company and industry association representatives as being the link in the 3TG mineral supply chain through which these minerals can be traced to their source of origin (mine); determining the point of origin is critical to establishing a transparent conflict mineral supply chain. This fact sheet, the first in a series of 3TG mineral fact sheets, focuses on the tungsten supply chain by listing plants that consume tungsten concentrates to produce ammonium paratungstate and ferrotungsten worldwide.

The One-carbon Carrier Methylofuran from Methylobacterium extorquens AM1 Contains a Large Number of α- and γ-Linked Glutamic Acid Residues*

PubMed Central

Hemmann, Jethro L.; Saurel, Olivier; Ochsner, Andrea M.; Stodden, Barbara K.; Kiefer, Patrick; Milon, Alain; Vorholt, Julia A.

2016-01-01

Methylobacterium extorquens AM1 uses dedicated cofactors for one-carbon unit conversion. Based on the sequence identities of enzymes and activity determinations, a methanofuran analog was proposed to be involved in formaldehyde oxidation in Alphaproteobacteria. Here, we report the structure of the cofactor, which we termed methylofuran. Using an in vitro enzyme assay and LC-MS, methylofuran was identified in cell extracts and further purified. From the exact mass and MS-MS fragmentation pattern, the structure of the cofactor was determined to consist of a polyglutamic acid side chain linked to a core structure similar to the one present in archaeal methanofuran variants. NMR analyses showed that the core structure contains a furan ring. However, instead of the tyramine moiety that is present in methanofuran cofactors, a tyrosine residue is present in methylofuran, which was further confirmed by MS through the incorporation of a 13C-labeled precursor. Methylofuran was present as a mixture of different species with varying numbers of glutamic acid residues in the side chain ranging from 12 to 24. Notably, the glutamic acid residues were not solely γ-linked, as is the case for all known methanofurans, but were identified by NMR as a mixture of α- and γ-linked amino acids. Considering the unusual peptide chain, the elucidation of the structure presented here sets the basis for further research on this cofactor, which is probably the largest cofactor known so far. PMID:26895963

Entropic benefit of a cross-link in protein association.

PubMed

Zaman, Muhammad H; Berry, R Stephen; Sosnick, Tobin R

2002-08-01

We introduce a method to estimate the loss of configurational entropy upon insertion of a cross-link to a dimeric system. First, a clear distinction is established between the loss of entropy upon tethering and binding, two quantities that are often considered to be equivalent. By comparing the probability distribution of the center-to-center distances for untethered and cross-linked versions, we are able to calculate the loss of translational entropy upon cross-linking. The distribution function for the untethered helices is calculated from the probability that a given helix is closer to its partner than to all other helices, the "Nearest Neighbor" method. This method requires no assumptions about the nature of the solvent, and hence resolves difficulties normally associated with calculations for systems in liquids. Analysis of the restriction of angular freedom upon tethering indicates that the loss of rotational entropy is negligible. The method is applied in the context of the folding of a ten turn helical coiled coil with the tether modeled as a Gaussian chain or a flexible amino acid chain. After correcting for loop closure entropy in the docked state, we estimate the introduction of a six-residue tether in the coiled coil results in an effective concentration of the chain to be about 4 or 100 mM, depending upon whether the helices are denatured or pre-folded prior to their association. Thus, tethering results in significant stabilization for systems with millimolar or stronger dissociation constants. Copyright 2002 Wiley-Liss, Inc.

From strings to coils: Rotational dynamics of DNA-linked colloidal chains

NASA Astrophysics Data System (ADS)

Kuei, Steve; Garza, Burke; Biswal, Sibani Lisa

2017-10-01

We investigate the dynamical behavior of deformable filaments experimentally using a tunable model system consisting of linked paramagnetic colloidal particles, where the persistence length lp, the contour length lc, and the strength and frequency of the external driving force are controlled. We find that upon forcing by an external magnetic field, a variety of structural and conformational regimes exist. Depending on the competition of forces and torques on the chain, we see classic rigid rotator behavior, as well as dynamically rich wagging, coiling, and folding behavior. Through a combination of experiments, computational models, and theoretical calculations, we are able to observe, classify, and predict these dynamics as a function of the dimensionless Mason and magnetoelastic numbers.

Monte Carlo Simulation of Endlinking Oligomers

NASA Technical Reports Server (NTRS)

Hinkley, Jeffrey A.; Young, Jennifer A.

1998-01-01

This report describes initial efforts to model the endlinking reaction of phenylethynyl-terminated oligomers. Several different molecular weights were simulated using the Bond Fluctuation Monte Carlo technique on a 20 x 20 x 20 unit lattice with periodic boundary conditions. After a monodisperse "melt" was equilibrated, chain ends were linked whenever they came within the allowed bond distance. Ends remained reactive throughout, so that multiple links were permitted. Even under these very liberal crosslinking assumptions, geometrical factors limited the degree of crosslinking. Average crosslink functionalities were 2.3 to 2.6; surprisingly, they did not depend strongly on the chain length. These results agreed well with the degrees of crosslinking inferred from experiment in a cured phenylethynyl-terminated polyimide oligomer.

Crystal structure of poly[{μ-N,N′-bis[(pyridin-4-yl)meth­yl]oxalamide}-μ-oxalato-cobalt(II)

PubMed Central

Zou, Hengye; Qi, Yanjuan

2014-01-01

In the polymeric title compound, [Co(C2O4)(C14H14N4O2)]n, the CoII atom is six-coordinated by two N atoms from symmetry-related bis­[(pyridin-4-yl)meth­yl]oxalamide (BPMO) ligands and four O atoms from two centrosymmetric oxalate anions in a distorted octa­hedral coordination geometry. The CoII atoms are linked by the oxalate anions into a chain running parallel to [100]. The chains are linked by the BPMO ligands into a three-dimensional architecture. In addition, N—H⋯O hydrogen bonds stabilize the crystal packing. PMID:25309173

Side-chain mobility in the folded state of Myoglobin

NASA Astrophysics Data System (ADS)

Lammert, Heiko; Onuchic, Jose

We study the accessibility of alternative side-chain rotamer configurations in the native state of Myoglobin, using an all-atom structure-based model. From long, unbiased simulation trajectories we determine occupancies of rotameric states and also estimate configurational and vibrational entropies. Direct sampling of the full native-state dynamics, enabled by the simple model, reveals facilitation of side-chain motions by backbone dynamics. Correlations between different dihedral angles are quantified and prove to be weak. We confirm global trends in the mobilities of side-chains, following burial and also the chemical character of residues. Surface residues loose little configurational entropy upon folding; side-chains contribute significantly to the entropy of the folded state. Mobilities of buried side-chains vary strongly with temperature. At ambient temperature, individual side-chains in the core of the protein gain substantial access to alternative rotamers, with occupancies that are likely observable experimentally. Finally, the dynamics of buried side-chains may be linked to the internal pockets, available to ligand gas molecules in Myoglobin.

Antihypertensive neutral lipid

DOEpatents

Snyder, Fred L.; Blank, Merle L.

1986-01-01

The invention relates to the discovery of a class of neutral acetylated ether-linked glycerolipids having the capacity to lower blood pressure in warm-blooded animals. This physiological effect is structure sensitive requiring a long chain alkyl group at the sn-1 position and a short carbon chain acyl group (acetyl or propionyl) at the sn-2 position, and a hydroxyl group at the sn-3 position.

Antihypertensive neutral lipid

DOEpatents

Snyder, F.L.; Blank, M.L.

1984-10-26

The invention relates to the discovery of a class of neutral acetylated either-linked glycerolipids having the capacity to lower blood presure in warm-blooded animals. This physiological effect is structure sensitive requiring a long chain alkyl group at the sn-1 position and a short carbon chain acyl group (acetyl or propionyl) at the sn-2 position, and a hydroxyl group at the sn-3 position.

Statistics of acoustic emissions and stress drops during granular shearing using a stick-slip fiber bundle mode

NASA Astrophysics Data System (ADS)

Cohen, D.; Michlmayr, G.; Or, D.

2012-04-01

Shearing of dense granular materials appears in many engineering and Earth sciences applications. Under a constant strain rate, the shearing stress at steady state oscillates with slow rises followed by rapid drops that are linked to the build up and failure of force chains. Experiments indicate that these drops display exponential statistics. Measurements of acoustic emissions during shearing indicates that the energy liberated by failure of these force chains has power-law statistics. Representing force chains as fibers, we use a stick-slip fiber bundle model to obtain analytical solutions of the statistical distribution of stress drops and failure energy. In the model, fibers stretch, fail, and regain strength during deformation. Fibers have Weibull-distributed threshold strengths with either quenched and annealed disorder. The shape of the distribution for drops and energy obtained from the model are similar to those measured during shearing experiments. This simple model may be useful to identify failure events linked to force chain failures. Future generalizations of the model that include different types of fiber failure may also allow identification of different types of granular failures that have distinct statistical acoustic emission signatures.

A novel pendulum test for measuring roller chain efficiency

NASA Astrophysics Data System (ADS)

Wragge-Morley, R.; Yon, J.; Lock, R.; Alexander, B.; Burgess, S.

2018-07-01

This paper describes a novel pendulum decay test for determining the transmission efficiency of chain drives. The test involves releasing a pendulum with an initial potential energy and measuring its decaying oscillations: under controlled conditions the decay reveals the losses in the transmission to a high degree of accuracy. The main advantage over motorised rigs is that there are significantly fewer sources of friction and inertia and hence measurement error. The pendulum rigs have an accuracy around 0.6% for the measurement of the coefficient of friction, giving an accuracy of transmission efficiency measurement around 0.012%. A theoretical model of chain friction combined with the equations of motion enables the coefficient of friction to be determined from the decay rate of pendulum velocity. The pendulum rigs operate at relatively low speeds. However, they allow an accurate determination of the coefficient of friction to estimate transmission efficiency at higher speeds. The pendulum rig revealed a previously undetected rocking behaviour in the chain links at very small articulation angles. In this regime, the link interfaces were observed to roll against one another rather than slide. This observation indicates that a very high-efficiency transmission can be achieved if the articulation angle is very low.

The E2-25K Ubiquitin-associated (UBA) Domain Aids in Polyubiquitin Chain Synthesis and Linkage Specificity

PubMed Central

WILSON, Randall C.; EDMONDSON, Stephen P.; FLATT, Justin W.; HELMS, Kimberli; TWIGG, Pamela D.

2011-01-01

E2-25K is an ubiquitin-conjugating enzyme with the ability to synthesize Lys48-linked polyubiquitin chains. E2-25K and its homologues represent the only known E2 enzymes which contain a C-terminal ubiquitin-associated (UBA) domain as well as the conserved catalytic ubiquitin-conjugating (UBC) domain. As an additional non-covalent binding surface for ubiquitin, the UBA domain must provide some functional specialization. We mapped the protein-protein interface involved in the E2-25K UBA/ubiquitin complex by solution nuclear magnetic resonance (NMR) spectroscopy and subsequently modeled the structure of the complex. Domain-domain interactions between the E2-25K catalytic UBC domain and the UBA domain do not induce significant structural changes in the UBA domain or alter the affinity of the UBA domain for ubiquitin. We determined that one of the roles of the C-terminal UBA domain, in the context of E2-25K, is to increase processivity in Lys48-linked polyubiquitin chain synthesis, possibly through increased binding to the ubiquitinated substrate. Additionally, we see evidence that the UBA domain directs specificity in polyubiquitin chain linkage. PMID:21281599

Does Sensitivity to Magnitude Depend on the Temporal Distribution of Reinforcement?

ERIC Educational Resources Information Center

Grace, Randolph C.; Bragason, Orn

2005-01-01

Our research addressed the question of whether sensitivity to relative reinforcer magnitude in concurrent chains depends on the distribution of reinforcer delays when the terminal-link schedules are equal. In Experiment 1, 12 pigeons responded in a two-component procedure. In both components, the initial links were concurrent variable-interval 40…

Tension-induced binding of semiflexible biopolymers

NASA Astrophysics Data System (ADS)

Benetatos, Panayotis; von der Heydt, Alice; Zippelius, Annette

2015-03-01

We investigate theoretically the effect of polymer tension on the collective behaviour of reversible cross-links. We use a model of two parallel-aligned, weakly-bending wormlike chains with a regularly spaced sequence of binding sites subjected to a tensile force. Reversible cross-links attach and detach at the binding sites with an affinity controlled by a chemical potential. In a mean-field approach, we calculate the free energy of the system and we show the emergence of a free energy barrier which controls the reversible (un)binding. The tension affects the conformational entropy of the chains which competes with the binding energy of the cross-links. This competition gives rise to a sudden increase in the fraction of bound sites as the polymer tension increases. The force-induced first-order transition in the number of cross-links implies a sudden force-induced stiffening of the effective stretching modulus of the polymers. This mechanism may be relevant to the formation and stress-induced strengthening of stress fibers in the cytoskeleton. We acknowledge support by the Deutsche Forschungsgemeinschaft (DFG) via grant SFB-937/A1.

Potassium deca­borate monohydrate

PubMed Central

Gao, Yi-Hong

2011-01-01

In the crystal structure of the title compound, K2[B10O14(OH)4]·H2O, the polyborate [B10O14(OH)4]2− anions are linked together through their common O atoms, forming a helical chain-like structure. Adjacent chains are further connected into a three-dimensional structure by O—H⋯O hydrogen bonds. The water mol­ecules and potassium cations are located between these chains. Further O—H⋯O hydrogen bonds occur between the anions and the water mol­ecules PMID:22058681

Isotype analysis of the anti-CENP-B anticentromere autoantibody: evidence for restricted clonality.

PubMed

Eisenberg, R A; Earnshaw, W C; Bordwell, B J; Craven, S Y; Cheek, R; Rothfield, N F

1989-10-01

Utilizing the centromere B fusion protein (CENP-B) and specific, matched monoclonal antiisotype reagents in an enzyme-linked immunosorbent assay, we found that anti-CENP-B autoantibodies were skewed to the IgG1 isotype. The overall kappa:lambda light chain ratio was 2:1, although several individual sera showed a strong predominance of one of the light chains. Isoelectric focusing of light chain-skewed sera showed polyclonal patterns. Our findings are consistent with the anti-CENP-B autoantibody response being a chronic, antigen-driven response.

Environmental footprints in the meat chain

NASA Astrophysics Data System (ADS)

Đekić, I.; Tomašević, I.

2017-09-01

The objective of this paper was to present environmental performance of the meat chain and highlight main environmental footprints. The meat sector is recognized as one of the leading polluting sectors in the food industry. The meat chain was analyzed from a five-link perspective introducing the following actors: farm(er)s, slaughterhouses, meat processors, customers and consumers. Meat production needs natural resources (water and energy) resulting in waste and waste water discharge. As an outcome it has a high influence on climate change in respect to global warming, acidification and eutrophication potentials and ozone depletion substances.

Scaling of Linking and Writhing Numbers for Spherically Confined and Topologically Equilibrated Flexible Polymers

PubMed Central

Marko, John F.

2011-01-01

Scaling laws for Gauss linking number Ca and writhing number Wr for spherically confined flexible polymers with thermally fluctuating topology are analyzed. For ideal (phantom) polymers each of N segments of length unity confined to a spherical pore of radius R there are two scaling regimes: for sufficiently weak confinement (R ⪢ N1/3) each chain has |Wr| ≈ N1/2, and each pair of chains has average |Ca| ≈ N/R3/2; alternately for sufficiently tight confinement (N1/3 ⪢ R), |Wr| ≈ |CA| ≈ N/R3/2. Adding segment-segment avoidance modifies this result: for n chains with excluded volume interactions |Ca| ≈ (N/n)1/2f(ϕ) where f is a scaling function that depends approximately linearly on the segment concentration ϕ = nN/R3. Scaling results for writhe are used to estimate the maximum writhe of a polymer; this is demonstrated to be realizable through a writhing instability that occurs for a polymer which is able to change knotting topology and which is subject to an applied torque. Finally, scaling results for linking are used to estimate bounds on the entanglement complexity of long chromosomal DNA molecules inside cells, and to show how “lengthwise” chromosome condensation can suppress DNA entanglement. PMID:21686050

Analysis of reduced monoclonal antibodies using size exclusion chromatography coupled with mass spectrometry

NASA Astrophysics Data System (ADS)

Liu, Hongcheng; Gaza-Bulseco, Georgeen; Chumsae, Chris

2009-12-01

Size-exclusion chromatography (SEC) has been widely used to detect antibody aggregates, monomer, and fragments. SEC coupled to mass spectrometry has been reported to measure the molecular weights of antibody; antibody conjugates, and antibody light chain and heavy chain. In this study, separation of antibody light chain and heavy chain by SEC and direct coupling to a mass spectrometer was further studied. It was determined that employing mobile phases containing acetonitrile, trifluoroacetic acid, and formic acid allowed the separation of antibody light chain and heavy chain after reduction by SEC. In addition, this mobile phase allowed the coupling of SEC to a mass spectrometer to obtain a direct molecular weight measurement. The application of the SEC-MS method was demonstrated by the separation of the light chain and the heavy chain of multiple recombinant monoclonal antibodies. In addition, separation of a thioether linked light chain and heavy chain from the free light chain and the free heavy chain of a recombinant monoclonal antibody after reduction was also achieved. This optimized method provided a separation of antibody light chain and heavy chain based on size and allowed a direct measurement of molecular weights by mass spectrometry. In addition, this method may help to identify peaks eluting from SEC column directly.

Real-Time Optimal Flood Control Decision Making and Risk Propagation Under Multiple Uncertainties

NASA Astrophysics Data System (ADS)

Zhu, Feilin; Zhong, Ping-An; Sun, Yimeng; Yeh, William W.-G.

2017-12-01

Multiple uncertainties exist in the optimal flood control decision-making process, presenting risks involving flood control decisions. This paper defines the main steps in optimal flood control decision making that constitute the Forecast-Optimization-Decision Making (FODM) chain. We propose a framework for supporting optimal flood control decision making under multiple uncertainties and evaluate risk propagation along the FODM chain from a holistic perspective. To deal with uncertainties, we employ stochastic models at each link of the FODM chain. We generate synthetic ensemble flood forecasts via the martingale model of forecast evolution. We then establish a multiobjective stochastic programming with recourse model for optimal flood control operation. The Pareto front under uncertainty is derived via the constraint method coupled with a two-step process. We propose a novel SMAA-TOPSIS model for stochastic multicriteria decision making. Then we propose the risk assessment model, the risk of decision-making errors and rank uncertainty degree to quantify the risk propagation process along the FODM chain. We conduct numerical experiments to investigate the effects of flood forecast uncertainty on optimal flood control decision making and risk propagation. We apply the proposed methodology to a flood control system in the Daduhe River basin in China. The results indicate that the proposed method can provide valuable risk information in each link of the FODM chain and enable risk-informed decisions with higher reliability.

Cooperative Order-Disorder Transition of Carboxylated Schizophyllan in Water-Dimethylsulfoxide Mixtures.

PubMed

Yoshiba, Kazuto; Dobashi, Toshiaki; Ulset, Ann-Sissel T; Christensen, Bjørn E

2018-06-18

Carboxylated schizophyllan ("sclerox") is a chemically modified polysaccharide obtained by partial periodate oxidation and subsequent chlorite oxidation of schizophyllan, a water-soluble neutral polysaccharide having a β-1,3-linked glucan backbone and a β-1,6-linked d-glucose residue side chain at every third residue of the main chain. The triple helix of schizophyllan in water has a cooperative order-disorder transition associated with the side chains. The transition is strongly affected by the presence (mole fraction) of dimethylsulfoxide (DMSO). In the present study, the solvent effects on the order-disorder transition of sclerox with different degrees of carboxylation (DS) in water-DMSO mixtures were investigated with differential scanning calorimetry and optical rotation. The transition temperature ( T r ) and transition enthalpy (Δ H r ) strongly depended on the mole fraction of DMSO ( x D ). Data were further analyzed with the statistical theory for the linear cooperative transition, taking into account the solvent effect, where DMSO molecules are selectively associated with the unmodified side chains. The modified side chain does not contribute to the transition; hence, Δ H r decreases with increasing DS. The dependence of T r on the DMSO content becomes weaker than that for unmodified schizophyllan. The theoretical analyses indicated that the number of sites binding with the DMSO molecule and the successive ordered sequence of the ordered unit of the triple helix are changed by carboxylation.

Selection of single chain antibody fragments binding to the extracellular domain of 4-1BB receptor by phage display technology.

PubMed

Bagheri, Salman; Yousefi, Mehdi; Safaie Qamsari, Elmira; Riazi-Rad, Farhad; Abolhassani, Mohsen; Younesi, Vahid; Dorostkar, Ruhollah; Movassaghpour, Ali Akbar; Sharifzadeh, Zahra

2017-03-01

The 4-1BB is a surface glycoprotein that pertains to the tumor necrosis factor-receptor family. There is compelling evidence suggesting important roles for 4-1BB in the immune response, including cell activation and proliferation and also cytokine induction. Because of encouraging results of different agonistic monoclonal antibodies against 4-1BB in the treatment of cancer, infectious, and autoimmune diseases, 4-1BB has been suggested as an attractive target for immunotherapy. In this study, single chain variable fragment phage display libraries, Tomlinson I+J, were screened against specific synthetic oligopeptides (peptides I and II) designed from 4-1BB extracellular domain. Five rounds of panning led to selection of four 4-1BB specific single chain variable fragments (PI.12, PI.42, PII.16, and PII.29) which showed specific reaction to relevant peptides in phage enzyme-linked immunosorbent assay. The selected clones were successfully expressed in Escherichia coli Rosetta-gami 2, and their expression was confirmed by western blot analysis. Enzyme-linked immunosorbent assay experiments indicated that these antibodies were able to specifically recognize 4-1BB without any cross-reactivity with other antigens. Flow cytometry analysis demonstrated an acceptable specific binding of the single chain variable fragments to 4-1BB expressed on CCRF-CEM cells, while no binding was observed with an irrelevant antibody. Anti-4-1BB single chain variable fragments enhanced surface CD69 expression and interleukin-2 production in stimulated CCRF-CEM cells which confirmed the agonistic effect of the selected single chain variable fragments. The data from this study have provided a rationale for further experiments involving the biological functions of anti-4-1BB single chain variable fragments in future studies.

Solvothermal syntheses and characterization of three new silver(I)/copper(I)-thioarsenates based on As2+/As3+ ions

NASA Astrophysics Data System (ADS)

Yao, Hua-Gang; Tang, Cheng-Fei; An, Yong-Lin; Ou, Zi-Jian; Wu, Guo-Hao; Lan, Pei; Zheng, Yi-Long

2017-02-01

Three new silver(I)/copper(I)-thioarsenates KAgAsIIS2 (1), RbCu2AsIIIS3 (2) and RbCu4AsIIIS4 (3) have been solvothermally synthesized and structurally characterized. 1 exhibits a two-dimensional anionic network built up by As-As bond connecting the left- and right-handed helical [AgS2]4- chains, and represents the first examples of thioarsenates(II). The structure of 2 consists of two kinds of helical [Cu2S3]4- chains linked by the arsenic atoms to form double layers with rubidium ions between the layers. Compound 3 is built up of infinite [Cu2S2]2- chain and layered [Cu6As2S6] linked to form a three-dimensional anionic framework, [Cu4AsS4]-, and containing channels in which the rubidium cations reside. The optical properties of 1-3 have been investigated by UV-vis spectroscopy.

Complexation of β-cyclodextrin with dual molecular probes bearing fluorescent and paramagnetic moieties linked by short polyether chains.

PubMed

Mocanu, S; Matei, I; Ionescu, S; Tecuceanu, V; Marinescu, G; Ionita, P; Culita, D; Leonties, A; Ionita, Gabriela

2017-10-18

Electron paramagnetic resonance (EPR) and fluorescence spectroscopies provide molecular-level insights on the interaction of paramagnetic and fluorescent species with the microenvironment. A series of dual molecular probes bearing fluorescent and paramagnetic moieties linked by flexible short polyether chains have been synthesized. These new molecular probes open the possibility to investigate various multi-component systems such as host-guest systems, polymeric micelles, gels and protein solutions by using EPR and fluorescence spectroscopies concertedly. The EPR and fluorescence spectra of these compounds show that the dependence of the rotational correlation time and fluorescence quantum yield on the chain length of the linker is not linear, due to the flexibility of the polyether linker. The quenching effect of the nitroxide moiety on the fluorescence intensity of the pyrene group varies with the linker length and flexibility. The interaction of these dual molecular probes with β-cyclodextrin, in solution and in polymeric gels, was evaluated and demonstrated by analysis of EPR and fluorescence spectra.

Tracing global supply chains to air pollution hotspots

NASA Astrophysics Data System (ADS)

Moran, Daniel; Kanemoto, Keiichiro

2016-09-01

While high-income countries have made significant strides since the 1970s in improving air quality, air pollution continues to rise in many developing countries and the world as a whole. A significant share of the pollution burden in developing countries can be attributed to production for export to consumers in high-income nations. However, it remains a challenge to quantify individual actors’ share of responsibility for pollution, and to involve parties other than primary emitters in cleanup efforts. Here we present a new spatially explicit modeling approach to link SO2, NO x , and PM10 severe emissions hotspots to final consumers via global supply chains. These maps show developed countries reducing their emissions domestically but driving new pollution hotspots in developing countries. This is also the first time a spatially explicit footprint inventory has been established. Linking consumers and supply chains to emissions hotspots creates opportunities for other parties to participate alongside primary emitters and local regulators in pollution abatement efforts.

Processing of N-linked oligosaccharides from precursor- to mature-form herpes simplex virus type 1 glycoprotein gC.

PubMed

Serafini-Cessi, F; Dall'Olio, F; Pereira, L; Campadelli-Fiume, G

1984-09-01

Immature and mature forms of glycoprotein gC were purified by immunoadsorbent from herpes simplex virus type 1-infected BHK cells labeled with [3H]mannose for a 20-min pulse or for 11 h followed by a 3-h chase. The nature of N-asparagine-linked oligosaccharides carried by the immature form, pgC (molecular weight = 92,000), and the mature gC (molecular weight = 120,000) has been investigated. All pronase-digested glycopeptides of pgC were susceptible to endo-beta-N-acetylglucosaminidase H treatment; thus they have a high-mannose structure. Using thin-layer chromatography to separate endo-beta-N-acetylglucosaminidase H-cleaved oligosaccharides, polymannosyl chains of different sizes, ranging from Man9GlcNAc to Man5GlcNAc, were separated. The major components were Man8GlcNAc and Man7GlcNAc, suggesting that pgC labeled in a 20-min pulse represents the form of glycoprotein already routed to the Golgi apparatus. Analysis of glycopeptides of mature gC showed that the majority (95%) of N-linked glycans were converted to complex-type glycans. Ion-exchange chromatography and affinity chromatography on concanavalin A-Sepharose and leucoagglutinin-agarose revealed that diantennary and triantennary glycans predominated, whereas tetrantennary chains were not present. Parts of the di- and triantennary chains were not fully sialylated. The high heterogeneity of complex-type chains found in mature gC may be related to the high number of N-glycosylation sites of the glycoprotein as predicted by DNA sequencing studies (Frink et al., J. Virol. 45:634-647, 1983).

Water-soluble polysaccharides from Pleurotus ostreatus var. florida mycelial biomass.

PubMed

Komura, Dirce L; Ruthes, Andrea C; Carbonero, Elaine R; Gorin, Philip A J; Iacomini, Marcello

2014-09-01

Pleurotus ostreatus var. florida known as Hiratake has a high nutritional value, presents medicinal and nutraceutical properties and it is one of the consumed mushrooms in Brazil. Thus, the aim of this study was to characterize the chemical structure of polysaccharides found in mycelial biomass produced by submerged culture of P. ostreatus var. florida in order to compare with those found in P. ostreatus var. florida fruit bodies. Aqueous and alkali extracts obtained from mycelial biomass were purified, 13C NMR, GC-MS and chemical techniques were used to characterize three polysaccharide structures: a mannogalactan (MG-PfM) with α-D-Galp and 3-O-Me-α-D-Galp units, both (1→6)-linked, highly substituted at O-2 by D-Manp, a glycogen-like polymer (GLY-PfM) with α-D-Glp (1→4)-linked main chain, partially substituted at O-6 by α-D-Glcp side chains and a (1→3), (1→6) β-D-glucan (βGLC-PfM) with a main chain of β-D-Glcp (1→3)-linked units, partially substituted at O-6 by side chains of 6-O-substituted β-D-glucopyranosyl units, on an average of one to every two residues of the backbone. These results show the possibility to obtain similar and also different molecules from those found in the fruiting body of the same mushroom species, therefore the submerged culture of mushroom is a promising way to give raise molecules of interest. Copyright © 2014. Published by Elsevier B.V.

NMR (Nuclear Magnetic Resonance) and macromolecular migration in a melt or in concentrated solutions

NASA Technical Reports Server (NTRS)

Addad, J. P. C.

1983-01-01

The purpose of this paper is to analyze the migration process of long polymer molecules in a melt or in concentrated solutions as it may be observed from the dynamics of the transverse magnetization of nuclear spins linked to these chains. The low frequency viscoelastic relaxation of polymer systems is known to be mainly controlled by the mechanism of dissociation of topological constraints excited on chains and which are called entanglements. This mechanism exhibits a strong dependence upon the chain molecular weight. These topological constraints also govern the diffusion process of polymer chains. So, the accurate description of the diffusion motion of a chain may be a convenient way to characterize disentanglement processes necessarily involved in any model proposed to explain viscoelastic effects.

The Analysis of Orders of Perishable Goods in Relation to the Bullwhip Effect in the Logistic Supply Chain of the Food Industry: a Case Study

NASA Astrophysics Data System (ADS)

Chocholáč, Jan; Průša, Petr

2016-12-01

The bullwhip effect generally refers to the phenomenon where order variability increases as the orders move upstream in the supply chain. It is serious problem for every member of the supply chain. This effect begins at customers and passes through the chain to producers, which are at the end of the logistic chain. Especially food supply chains are affected by this issue. These chains are unique for problems of expiration of goods (particularly perishable goods), variable demand, orders with quantity discounts and effort to maximize the customer satisfaction. This paper will present the problem of the bullwhip effect in the real supply chain in the food industry. This supply chain consists of approximately 350 stores, four central warehouses and more than 1000 suppliers, but the case study will examine 87 stores, one central warehouse and one supplier in 2015. The aim of this paper is the analysis of the order variability between the various links in this chain and confirmation of the bullwhip effect in this chain. The subject of the analysis will be perishable goods.

Modeling methodology for supply chain synthesis and disruption analysis

NASA Astrophysics Data System (ADS)

Wu, Teresa; Blackhurst, Jennifer

2004-11-01

The concept of an integrated or synthesized supply chain is a strategy for managing today's globalized and customer driven supply chains in order to better meet customer demands. Synthesizing individual entities into an integrated supply chain can be a challenging task due to a variety of factors including conflicting objectives, mismatched incentives and constraints of the individual entities. Furthermore, understanding the effects of disruptions occurring at any point in the system is difficult when working toward synthesizing supply chain operations. Therefore, the goal of this research is to present a modeling methodology to manage the synthesis of a supply chain by linking hierarchical levels of the system and to model and analyze disruptions in the integrated supply chain. The contribution of this research is threefold: (1) supply chain systems can be modeled hierarchically (2) the performance of synthesized supply chain system can be evaluated quantitatively (3) reachability analysis is used to evaluate the system performance and verify whether a specific state is reachable, allowing the user to understand the extent of effects of a disruption.

Endoglycosidase and glycoamidase release of N-linked oligosaccharides.

PubMed

Freeze, H H

2001-05-01

Carbohydrate chain modifications are often used to monitor glycoprotein movement through the secretory pathway. This is because stepwise sugar-chain processing is unidirectional and generally corresponds to the forward or anterograde movement of proteins. This unit offers a group of techniques that will help analyze the general structure of carbohydrate chains on a protein and, therefore, oligosaccharide processing mileposts. The sugar chains themselves are not analyzed, but their presence and structure are inferred from gel mobility differences after one or more enzymatic digestions. This approach is most often used in combination with [35S]Met pulse-chase metabolic labeling protocols, but they can be applied to any suitably labeled protein (e.g., biotinylated or 125I-labeled).

Generation of human scFv antibody libraries: PCR amplification and assembly of light- and heavy-chain coding sequences.

PubMed

Andris-Widhopf, Jennifer; Steinberger, Peter; Fuller, Roberta; Rader, Christoph; Barbas, Carlos F

2011-09-01

The development of therapeutic antibodies for use in the treatment of human diseases has long been a goal for many researchers in the antibody field. One way to obtain these antibodies is through phage-display libraries constructed from human lymphocytes. This protocol describes the construction of human scFv (single chain antibody fragment) libraries using a short linker (GGSSRSS) or a long linker (GGSSRSSSSGGGGSGGGG). In this method, the individual rearranged heavy- and light-chain variable regions are amplified separately and are linked through a series of overlap polymerase chain reaction (PCR) steps to give the final scFv products that are used for cloning.

Fuzzy Entropy Method for Quantifying Supply Chain Networks Complexity

NASA Astrophysics Data System (ADS)

Zhang, Jihui; Xu, Junqin

Supply chain is a special kind of complex network. Its complexity and uncertainty makes it very difficult to control and manage. Supply chains are faced with a rising complexity of products, structures, and processes. Because of the strong link between a supply chain’s complexity and its efficiency the supply chain complexity management becomes a major challenge of today’s business management. The aim of this paper is to quantify the complexity and organization level of an industrial network working towards the development of a ‘Supply Chain Network Analysis’ (SCNA). By measuring flows of goods and interaction costs between different sectors of activity within the supply chain borders, a network of flows is built and successively investigated by network analysis. The result of this study shows that our approach can provide an interesting conceptual perspective in which the modern supply network can be framed, and that network analysis can handle these issues in practice.

Differential Impact of Response Effort within a Response Chain on Use of Mands in a Student with Autism

ERIC Educational Resources Information Center

Buckley, Scott D.; Newchok, Debra K.

2005-01-01

We investigated the effects of response effort on the use of mands during functional communication training (FCT) in a participant with autism. The number of links in a picture exchange response chain determined two levels of response effort. Each level was paired with a fixed ratio (FR3) schedule of reinforcement for aggression in a reversal…

A Comparison of Techniques for Optimal Infrastructure Restoration

DTIC Science & Technology

2014-12-01

to solve incremental network design problems. Álvarez et al. (2014) use a continuous MILP to solve the supply chain network infras- tructure problem...S. Long, T. Shoberg, S. Corns. 2014. A mathe- matical model for supply chain network infrastructure restoration. Y. Guan, H. Liao, eds., Proceedings...Links . . . . . . . . . . . . . . . . . 36 A.5 Use Supply from a Particular Node . . . . . . . . . . . . . . . . . 37 A.6 High Demand with High Building

Effects of preventing O-glycosylation on the secretion of human chorionic gonadotropin in Chinese hamster ovary cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matzuk, M.M.; Krieger, M.; Corless, C.L.

1987-09-01

Human chorionic gonadotropin (hCG) is a member of a family of heterodimeric glycoprotein hormones that have a common ..cap alpha.. subunit but differ in their hormone-specific ..beta..-subunits. The ..beta.. subunit of hCG (hCG..beta..) is unique among the ..beta.. subunits in that it contains four mucin-like O-linked oligosaccharides attached to a carboxyl-terminal extension. To study the effects of O-glycosylation on the secretion and assembly of hCG, expression vectors containing either hCG..beta.. gene alone or together with the hCG..cap alpha.. gene were transfected into a mutant Chinese hamster ovary cell line, 1d1D, which exhibits a reversible defect in O-glycosylation. The results revealmore » that hCG..beta.. can be secreted normally in the absence of its O-linked oligosaccharides. hCG..beta.. devoid of O-linked carbohydrate can also combine efficiently with hCG..cap alpha.. and be secreted as an intact dimer. The authors conclude that in Chinese hamster ovary cells, the hCG..beta.. O-linked chains play no role in the assembly and secretion of hCG. The normal and O-linked oligosaccharide-deficient forms of hCG secreted by these cells should prove useful in examining the role of O-linked chains on the biological function of hCG.« less

Effect of chain stiffness on the structure of single-chain polymer nanoparticles

NASA Astrophysics Data System (ADS)

Moreno, Angel J.; Bacova, Petra; Lo Verso, Federica; Arbe, Arantxa; Colmenero, Juan; Pomposo, José A.

2018-01-01

Polymeric single-chain nanoparticles (SCNPs) are soft nano-objects synthesized by purely intramolecular cross-linking of single polymer chains. By means of computer simulations, we investigate the conformational properties of SCNPs as a function of the bending stiffness of their linear polymer precursors. We investigate a broad range of characteristic ratios from the fully flexible case to those typical of bulky synthetic polymers. Increasing stiffness hinders bonding of groups separated by short contour distances and increases looping over longer distances, leading to more compact nanoparticles with a structure of highly interconnected loops. This feature is reflected in a crossover in the scaling behaviour of several structural observables. The scaling exponents change from those characteristic for Gaussian chains or rings in θ-solvents in the fully flexible limit, to values resembling fractal or ‘crumpled’ globular behaviour for very stiff SCNPs. We characterize domains in the SCNPs. These are weakly deformable regions that can be seen as disordered analogues of domains in disordered proteins. Increasing stiffness leads to bigger and less deformable domains. Surprisingly, the scaling behaviour of the domains is in all cases similar to that of Gaussian chains or rings, irrespective of the stiffness and degree of cross-linking. It is the spatial arrangement of the domains which determines the global structure of the SCNP (sparse Gaussian-like object or crumpled globule). Since intramolecular stiffness can be varied through the specific chemistry of the precursor or by introducing bulky side groups in its backbone, our results propose a new strategy to tune the global structure of SCNPs.

Meaning in Life: One Link in the Chain from Religiousness to Well-Being

ERIC Educational Resources Information Center

Steger, Michael F.; Frazier, Patricia

2005-01-01

Meaning in life has been identified as a potential mediator of the link between religiousness and psychological health. The authors tested this hypothesis in 2 studies, using multiple methods and measures of religiousness and well-being. In the studies, meaning in life mediated the relation between religiousness and life satisfaction (Study 1A),…

Synthetically Simple, Highly Resilient Hydrogels

PubMed Central

Cui, Jun; Lackey, Melissa A.; Madkour, Ahmad E.; Saffer, Erika M.; Griffin, David M.; Bhatia, Surita R.; Crosby, Alfred J.; Tew, Gregory N.

2014-01-01

Highly resilient synthetic hydrogels were synthesized by using the efficient thiol-norbornene chemistry to cross-link hydrophilic poly(ethylene glycol) (PEG) and hydrophobic polydimethylsiloxane (PDMS) polymer chains. The swelling and mechanical properties of the hydrogels were well-controlled by the relative amounts of PEG and PDMS. In addition, the mechanical energy storage efficiency (resilience) was more than 97% at strains up to 300%. This is comparable with one of the most resilient materials known: natural resilin, an elastic protein found in many insects, such as in the tendons of fleas and the wings of dragonflies. The high resilience of these hydrogels can be attributed to the well-defined network structure provided by the versatile chemistry, low cross-link density, and lack of secondary structure in the polymer chains. PMID:22372639

Robustness of assembly supply chain networks by considering risk propagation and cascading failure

NASA Astrophysics Data System (ADS)

Tang, Liang; Jing, Ke; He, Jie; Stanley, H. Eugene

2016-10-01

An assembly supply chain network (ASCN) is composed of manufacturers located in different geographical regions. To analyze the robustness of this ASCN when it suffers from catastrophe disruption events, we construct a cascading failure model of risk propagation. In our model, different disruption scenarios s are considered and the probability equation of all disruption scenarios is developed. Using production capability loss as the robustness index (RI) of an ASCN, we conduct a numerical simulation to assess its robustness. Through simulation, we compare the network robustness at different values of linking intensity and node threshold and find that weak linking intensity or high node threshold increases the robustness of the ASCN. We also compare network robustness levels under different disruption scenarios.

Crystal structure and Hirshfeld surface analysis of 3-cyano­phenyl­boronic acid

PubMed Central

Cárdenas-Valenzuela, A. Jaquelin; González-García, Gerardo; Zárraga- Nuñez, Ramón; Höpfl, Herbert; Campos-Gaxiola, José J.; Cruz-Enríquez, Adriana

2018-01-01

In the title compound, C7H6BNO2, the mean plane of the –B(OH)2 group is twisted by 21.28 (6)° relative to the cyano­phenyl ring mean plane. In the crystal, mol­ecules are linked by O—H⋯O and O—H⋯N hydrogen bonds, forming chains propagating along the [101] direction. Offset π–π and B⋯π stacking inter­actions link the chains, forming a three-dimensional network. Hirshfeld surface analysis shows that van der Waals inter­actions constitute a further major contribution to the inter­molecular inter­actions, with H⋯H contacts accounting for 25.8% of the surface. PMID:29765741

2-(3-Chloro­phen­yl)-4,5-dihydro-1H-imidazole

PubMed Central

Kia, Reza; Fun, Hoong-Kun; Kargar, Hadi

2009-01-01

In the title compound, C9H9ClN2, a substituted imidazoline, the six- and five-membered rings are twisted from each other, making a dihedral angle of 17.07 (5)°. In the crystal structure, a short Cl⋯Cl [3.3540 (3) Å] inter­action is observed. Neighbouring mol­ecules are linked together by inter­molecular N—H⋯N hydrogen bonds into a one-dimensional infinite chain along the [101] direction and short Cl⋯Cl contacts link the chains into a three-dimensional network. There is also a significant π-stacking inter­action between the planar sections of the six- and five-membered rings. PMID:21581940

Ethyl 2-[(carbamothioyl-amino)-imino]-propano-ate.

PubMed

Corrêa, Charlane C; Graúdo, José Eugênio J C; de Oliveira, Luiz Fernando C; de Almeida, Mauro V; Diniz, Renata

2011-08-01

The title compound, C(6)H(11)N(3)O(2)S, consists of a roughly planar mol-ecule (r.m.s deviation from planarity = 0.077 Å for the non-H atoms) and has the S atom in an anti position to the imine N atom. This N atom is the acceptor of a strongly bent inter-nal N-H⋯N hydrogen bond donated by the amino group. In the crystal, mol-ecules are arranged in undulating layers parallel to (010). The mol-ecules are linked via inter-molecular amino-carboxyl N-H⋯O hydrogen bonds, forming chains parallel to [001]. The chains are cross-linked by N(carbazone)-H⋯S and C-H⋯S inter-actions, forming infinite sheets.

Activation of duck RIG-I by TRIM25 is independent of anchored ubiquitin.

PubMed

Miranzo-Navarro, Domingo; Magor, Katharine E

2014-01-01

Retinoic acid inducible gene I (RIG-I) is a viral RNA sensor crucial in defense against several viruses including measles, influenza A and hepatitis C. RIG-I activates type-I interferon signalling through the adaptor for mitochondrial antiviral signaling (MAVS). The E3 ubiquitin ligase, tripartite motif containing protein 25 (TRIM25), activates human RIG-I through generation of anchored K63-linked polyubiquitin chains attached to lysine 172, or alternatively, through the generation of unanchored K63-linked polyubiquitin chains that interact non-covalently with RIG-I CARD domains. Previously, we identified RIG-I of ducks, of interest because ducks are the host and natural reservoir of influenza viruses, and showed it initiates innate immune signaling leading to production of interferon-beta (IFN-β). We noted that K172 is not conserved in RIG-I of ducks and other avian species, or mouse. Because K172 is important for both mechanisms of activation of human RIG-I, we investigated whether duck RIG-I was activated by TRIM25, and if other residues were the sites for attachment of ubiquitin. Here we show duck RIG-I CARD domains are ubiquitinated for activation, and ubiquitination depends on interaction with TRIM25, as a splice variant that cannot interact with TRIM25 is not ubiquitinated, and cannot be activated. We expressed GST-fusion proteins of duck CARD domains and characterized TRIM25 modifications of CARD domains by mass spectrometry. We identified two sites that are ubiquitinated in duck CARD domains, K167 and K193, and detected K63 linked polyubiquitin chains. Site directed mutagenesis of each site alone, does not alter the ubiquitination profile of the duck CARD domains. However, mutation of both sites resulted in loss of all attached ubiquitin and polyubiquitin chains. Remarkably, the double mutant duck RIG-I CARD still interacts with TRIM25, and can still be activated. Our results demonstrate that anchored ubiquitin chains are not necessary for TRIM25 activation of duck RIG-I.

In silico modeling of the cryptic E2∼ubiquitin-binding site of E6-associated protein (E6AP)/UBE3A reveals the mechanism of polyubiquitin chain assembly.

PubMed

Ronchi, Virginia P; Kim, Elizabeth D; Summa, Christopher M; Klein, Jennifer M; Haas, Arthur L

2017-11-03

To understand the mechanism for assembly of Lys 48 -linked polyubiquitin degradation signals, we previously demonstrated that the E6AP/UBE3A ligase harbors two functionally distinct E2∼ubiquitin-binding sites: a high-affinity Site 1 required for E6AP Cys 820 ∼ubiquitin thioester formation and a canonical Site 2 responsible for subsequent chain elongation. Ordered binding to Sites 1 and 2 is here revealed by observation of UbcH7∼ubiquitin-dependent substrate inhibition of chain formation at micromolar concentrations. To understand substrate inhibition, we exploited the PatchDock algorithm to model in silico UbcH7∼ubiquitin bound to Site 1, validated by chain assembly kinetics of selected point mutants. The predicted structure buries an extensive solvent-excluded surface bringing the UbcH7∼ubiquitin thioester bond within 6 Å of the Cys 820 nucleophile. Modeling onto the active E6AP trimer suggests that substrate inhibition arises from steric hindrance between Sites 1 and 2 of adjacent subunits. Confirmation that Sites 1 and 2 function in trans was demonstrated by examining the effect of E6APC820A on wild-type activity and single-turnover pulse-chase kinetics. A cyclic proximal indexation model proposes that Sites 1 and 2 function in tandem to assemble thioester-linked polyubiquitin chains from the proximal end attached to Cys 820 before stochastic en bloc transfer to the target protein. Non-reducing SDS-PAGE confirms assembly of the predicted Cys 820 -linked 125 I-polyubiquitin thioester intermediate. Other studies suggest that Glu 550 serves as a general base to generate the Cys 820 thiolate within the low dielectric binding interface and Arg 506 functions to orient Glu 550 and to stabilize the incipient anionic transition state during thioester exchange. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Cysteine S-linked N-acetylglucosamine (S-GlcNAcylation), A New Post-translational Modification in Mammals.

PubMed

Maynard, Jason C; Burlingame, Alma L; Medzihradszky, Katalin F

2016-11-01

Intracellular GlcNAcylation of Ser and Thr residues is a well-known and widely investigated post-translational modification. This post-translational modification has been shown to play a significant role in cell signaling and in many regulatory processes within cells. O-GlcNAc transferase is the enzyme responsible for glycosylating cytosolic and nuclear proteins with a single GlcNAc residue on Ser and Thr side-chains. Here we report that the same enzyme may also be responsible for S-GlcNAcylation, i.e. for linking the GlcNAc unit to the peptide by modifying a cysteine side-chain. We also report that O-GlcNAcase, the enzyme responsible for removal of O-GlcNAcylation does not appear to remove the S-linked sugar. Such Cys modifications have been detected and identified in mouse and rat samples. This work has established the occurrence of 14 modification sites assigned to 11 proteins unambiguously. We have also identified S-GlcNAcylation from human Host Cell Factor 1 isolated from HEK-cells. Although these site assignments are primarily based on electron-transfer dissociation mass spectra, we also report that S-linked GlcNAc is more stable under collisional activation than O-linked GlcNAc derivatives. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Polysaccharide structure of tetrasporic red seaweed Tichocarpus crinitus.

PubMed

Byankina Barabanova, A O; Sokolova, E V; Anastyuk, S D; Isakov, V V; Glazunov, V P; Volod'ko, A V; Yakovleva, I M; Solov'eva, T F; Yermak, I M

2013-10-15

Sulfated polysaccharide isolated from tetrasporic plants of Tichocarpus crinitus was investigated. The polysaccharide was isolated by two methods: with water extraction at 80 °C (HT) and with a mild alkaline extraction (AE). The extracted polysaccharides were presented by non-gelling ones only, while galactose and 3,6-AG were the main monosaccharides, at the same time amount of 3,6-AG in AE polysaccharides was the similar to that of HT. According to methods of spectroscopy and mass spectrometry, the polysaccharide from tetrasporic T. crinitus contains main blocks of 1,3-linked β-D-galactopyranosyl-2,4-disulfates and 1,4-linked 3,6-anhydro-α-D-galactopyranosyl while 6-sulfated 4-linked galactopyranosyl resudies are randomly distributed along the polysaccharide chain. The alkaline treatment of HT polysaccharide results in obtaining polysaccharide with regular structure that composed of alternating 1,3-linked β-D-galactopyranosyl-2,4-disulfates and 1,4-linked 3,6-anhydro-α-D-galactopyranosyl residues. Native polysaccharide (HT) possessed both high anticoagulant and antiplatelet activity measured by fibrin clotting and platelet aggregation induced by collagen. This activity could be connected with peculiar chemical structure of HT polysaccharide which has high sulfation degree and contains also 3,6-anhydrogalactose in the polymer chain. Copyright © 2013 Elsevier Ltd. All rights reserved.

The One-carbon Carrier Methylofuran from Methylobacterium extorquens AM1 Contains a Large Number of α- and γ-Linked Glutamic Acid Residues.

PubMed

Hemmann, Jethro L; Saurel, Olivier; Ochsner, Andrea M; Stodden, Barbara K; Kiefer, Patrick; Milon, Alain; Vorholt, Julia A

2016-04-22

Methylobacterium extorquens AM1 uses dedicated cofactors for one-carbon unit conversion. Based on the sequence identities of enzymes and activity determinations, a methanofuran analog was proposed to be involved in formaldehyde oxidation in Alphaproteobacteria. Here, we report the structure of the cofactor, which we termed methylofuran. Using an in vitro enzyme assay and LC-MS, methylofuran was identified in cell extracts and further purified. From the exact mass and MS-MS fragmentation pattern, the structure of the cofactor was determined to consist of a polyglutamic acid side chain linked to a core structure similar to the one present in archaeal methanofuran variants. NMR analyses showed that the core structure contains a furan ring. However, instead of the tyramine moiety that is present in methanofuran cofactors, a tyrosine residue is present in methylofuran, which was further confirmed by MS through the incorporation of a (13)C-labeled precursor. Methylofuran was present as a mixture of different species with varying numbers of glutamic acid residues in the side chain ranging from 12 to 24. Notably, the glutamic acid residues were not solely γ-linked, as is the case for all known methanofurans, but were identified by NMR as a mixture of α- and γ-linked amino acids. Considering the unusual peptide chain, the elucidation of the structure presented here sets the basis for further research on this cofactor, which is probably the largest cofactor known so far. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Supply chain planning classification

NASA Astrophysics Data System (ADS)

Hvolby, Hans-Henrik; Trienekens, Jacques; Bonde, Hans

2001-10-01

Industry experience a need to shift in focus from internal production planning towards planning in the supply network. In this respect customer oriented thinking becomes almost a common good amongst companies in the supply network. An increase in the use of information technology is needed to enable companies to better tune their production planning with customers and suppliers. Information technology opportunities and supply chain planning systems facilitate companies to monitor and control their supplier network. In spite if these developments, most links in today's supply chains make individual plans, because the real demand information is not available throughout the chain. The current systems and processes of the supply chains are not designed to meet the requirements now placed upon them. For long term relationships with suppliers and customers, an integrated decision-making process is needed in order to obtain a satisfactory result for all parties. Especially when customized production and short lead-time is in focus. An effective value chain makes inventory available and visible among the value chain members, minimizes response time and optimizes total inventory value held throughout the chain. In this paper a supply chain planning classification grid is presented based current manufacturing classifications and supply chain planning initiatives.

Productive Recognition of Factor IX by Factor XIa Exosites Requires Disulfide Linkage between Heavy and Light Chains of Factor XIa*

PubMed Central

Marcinkiewicz, Mariola M.; Sinha, Dipali; Walsh, Peter N.

2012-01-01

In the intrinsic pathway of blood coagulation factor XIa (FXIa) activates factor IX (FIX) by cleaving the zymogen at Arg145-Ala146 and Arg180-Val181 bonds releasing an 11-kDa activation peptide. FXIa and its isolated light chain (FXIa-LC) cleave S-2366 at comparable rates, but FXIa-LC is a very poor activator of FIX, possibly because FIX undergoes allosteric modification on binding to an exosite on the heavy chain of FXIa (FXIa-HC) required for optimal cleavage rates of the two scissile bonds of FIX. However preincubation of FIX with a saturating concentration of isolated FXIa-HC did not result in any potentiation in the rate of FIX cleavage by FXIa-LC. Furthermore, if FIX binding via the heavy chain exosite of FXIa determines the affinity of the enzyme-substrate interaction, then the isolated FXIa-HC should inhibit the rate of FIX activation by depleting the substrate. However, whereas FXIa/S557A inhibited FIX activation of by FXIa, FXIa-HC did not. Therefore, we examined FIX binding to FXIa/S557A, FXIa-HC, FXIa-LC, FXIa/C362S/C482S, and FXIa/S557A/C362S/C482S. The heavy and light chains are disulfide-linked in FXIa/S557A but not in FXIa/C362S/C482S and FXIa/S557A/C362S/C482S. In an ELISA assay only FXI/S557A ligated FIX with high affinity. Partial reduction of FXIa/S557A to produce heavy and light chains resulted in decreased FIX binding, and this function was regained upon reformation of the disulfide linkage between the heavy and the light chains. We therefore conclude that substrate recognition by the FXIa exosite(s) requires disulfide-linked heavy and light chains. PMID:22207756

Identification of high-mannose and multiantennary complex-type N-linked glycans containing alpha-galactose epitopes from Nurse shark IgM heavy chain.

PubMed

Harvey, David J; Crispin, Max; Moffatt, Beryl E; Smith, Sylvia L; Sim, Robert B; Rudd, Pauline M; Dwek, Raymond A

2009-11-01

MALDI-TOF mass spectrometry, negative ion nano-electrospray MS/MS and exoglycosidase digestion were used to identify 36 N-linked glycans from 19S IgM heavy chain derived from the nurse shark (Ginglymostoma cirratum). The major glycan was the high-mannose compound, Man(6)GlcNAc(2) accompanied by small amounts of Man(5)GlcNAc(2), Man(7)GlcNAc(2) and Man(8)GlcNAc(2). Bi- and tri-antennary (isomer with a branched 3-antenna) complex-type glycans were also abundant, most contained a bisecting GlcNAc residue (beta1-->4-linked to the central mannose) and with varying numbers of alpha-galactose residues capping the antennae. Small amounts of monosialylated glycans were also found. This appears to be the first comprehensive study of glycosylation in this species of animal. The glycosylation pattern has implications for the mechanism of activation of the complement system by nurse shark IgM.

2-(4-Hy-droxy-phen-yl)-1H-benzimidazol-3-ium chloride monohydrate.

PubMed

González-Padilla, Jazmin E; Rosales-Hernández, Martha Cecila; Padilla-Martínez, Itzia I; García-Báez, Efren V; Rojas-Lima, Susana

2013-01-01

The title mol-ecular salt, C13H11N2O(+)·Cl(-)·H2O, crystallizes as a monohydrate. In the cation, the phenol and benzimidazole rings are almost coplanar, making a dihedral angle of 3.18 (4)°. The chloride anion and benzimidazole cation are linked by two N(+)-H⋯Cl(-) hydrogen bonds, forming chains propagating along [010]. These chains are linked through O-H⋯Cl hydrogen bonds involving the water mol-ecule and the chloride anion, which form a diamond core, giving rise to the formation of two-dimensional networks lying parallel to (10-2). Two π-π inter-actions involving the imidazolium ring with the benzene and phenol rings [centroid-centroid distances = 3.859 (3) and 3.602 (3) Å, respectively], contribute to this second dimension. A strong O-H⋯O hydrogen bond involving the water mol-ecule and the phenol substituent on the benzimidazole unit links the networks, forming a three-dimensional structure.

Why do gelatinized starch granules not dissolve completely? Roles for amylose, protein, and lipid in granule "ghost" integrity.

PubMed

Debet, Martine R; Gidley, Michael J

2007-06-13

After gelatinization in water, starch granules persist in swollen hydrated forms known as ghosts. Three potential mechanisms for ghost formation are tested. Proteins and lipids on the granule surface are found to be a determinant of ghost robustness, but not ghost formation. Proteins inside pre-made maize or wheat starch ghosts are degraded extensively by proteases without any apparent change in ghost properties, making an internal protein cross-linking mechanism unlikely. Waxy maize mutants with a range of amylose contents have ghost integrities that correlate with (low) apparent amylose levels. It is hypothesized that ghost formation is due to cross-linking of polysaccharide chains within swollen granules, most likely involving double helices formed from polymer chains that become free to move following heat-induced granule swelling. The size and robustness of granule ghosts is proposed to be determined by the relative rates of swelling and cross-linking, modulated by surface non-polysaccharide components.

Tailoring chain length and cross-link density in dielectric elastomer toward enhanced actuation strain

NASA Astrophysics Data System (ADS)

Zhang, Quan-Ping; Liu, Jun-Hua; Liu, Hai-Dong; Jia, Fei; Zhou, Yuan-Lin; Zheng, Jian

2017-10-01

Adding ceramic or conductive fillers into polymers for increasing permittivity is a direct and effective approach to enhance the actuation strain of dielectric elastomer actuators (DEAs). Unfortunately, the major dielectric loss caused by weak interfaces potentially harms the electro-mechanical stability and lifetime of DEAs. Here, we construct a desired macromolecular network with a long chain length and low cross-link density to reduce the elastic modulus of silicone elastomers. Selecting a high molecular weight of polymethylvinylsiloxane and a low dose of the cross-linker leads the soft but tough networks with rich entanglements, poor cross-links, and a low amount of defects. Then, a ductile material with low elastic modulus but high elongation at break is obtained. It accounts for much more excellent actuation strain of Hl in comparison to that of the other silicone elastomers. Importantly, without other fillers, the ultralow dielectric loss, conductivity, and firm networks possibly promote the electro-mechanical stability and lifetime for the DEA application.

Sequence Analysis and Domain Motifs in the Porcine Skin Decorin Glycosaminoglycan Chain*

PubMed Central

Zhao, Xue; Yang, Bo; Solakylidirim, Kemal; Joo, Eun Ji; Toida, Toshihiko; Higashi, Kyohei; Linhardt, Robert J.; Li, Lingyun

2013-01-01

Decorin proteoglycan is comprised of a core protein containing a single O-linked dermatan sulfate/chondroitin sulfate glycosaminoglycan (GAG) chain. Although the sequence of the decorin core protein is determined by the gene encoding its structure, the structure of its GAG chain is determined in the Golgi. The recent application of modern MS to bikunin, a far simpler chondroitin sulfate proteoglycans, suggests that it has a single or small number of defined sequences. On this basis, a similar approach to sequence the decorin of porcine skin much larger and more structurally complex dermatan sulfate/chondroitin sulfate GAG chain was undertaken. This approach resulted in information on the consistency/variability of its linkage region at the reducing end of the GAG chain, its iduronic acid-rich domain, glucuronic acid-rich domain, and non-reducing end. A general motif for the porcine skin decorin GAG chain was established. A single small decorin GAG chain was sequenced using MS/MS analysis. The data obtained in the study suggest that the decorin GAG chain has a small or a limited number of sequences. PMID:23423381

Generation of human Fab antibody libraries: PCR amplification and assembly of light- and heavy-chain coding sequences.

PubMed

Andris-Widhopf, Jennifer; Steinberger, Peter; Fuller, Roberta; Rader, Christoph; Barbas, Carlos F

2011-09-01

The development of therapeutic antibodies for use in the treatment of human diseases has long been a goal for many researchers in the antibody field. One way to obtain these antibodies is through phage-display libraries constructed from human lymphocytes. This protocol describes the construction of human Fab (fragment antigen binding) antibody libraries. In this method, the individual rearranged heavy- and light-chain variable regions are amplified separately and are linked through a series of overlap polymerase chain reaction (PCR) steps to give the final Fab products that are used for cloning.

The UK waste input-output table: Linking waste generation to the UK economy.

PubMed

Salemdeeb, Ramy; Al-Tabbaa, Abir; Reynolds, Christian

2016-10-01

In order to achieve a circular economy, there must be a greater understanding of the links between economic activity and waste generation. This study introduces the first version of the UK waste input-output table that could be used to quantify both direct and indirect waste arisings across the supply chain. The proposed waste input-output table features 21 industrial sectors and 34 waste types and is for the 2010 time-period. Using the waste input-output table, the study results quantitatively confirm that sectors with a long supply chain (i.e. manufacturing and services sectors) have higher indirect waste generation rates compared with industrial primary sectors (e.g. mining and quarrying) and sectors with a shorter supply chain (e.g. construction). Results also reveal that the construction, mining and quarrying sectors have the highest waste generation rates, 742 and 694 tonne per £1m of final demand, respectively. Owing to the aggregated format of the first version of the waste input-output, the model does not address the relationship between waste generation and recycling activities. Therefore, an updated version of the waste input-output table is expected be developed considering this issue. Consequently, the expanded model would lead to a better understanding of waste and resource flows in the supply chain. © The Author(s) 2016.

Isolation and characterization of a thermally stable recombinant anti-caffeine heavy-chain antibody fragment.

PubMed

Ladenson, Ruth C; Crimmins, Dan L; Landt, Yvonne; Ladenson, Jack H

2006-07-01

We have isolated and characterized a caffeine-specific, heavy-chain-only antibody fragment (V(HH)) from llama that is capable of being utilized to analyze caffeine in hot and cold beverages. Camelid species (llama and camel) were selected for immunization because of their potential to make heat-stable, heavy-chain-only antibodies. Llamas and camels were immunized with caffeine covalently linked to keyhole limpet hemocyanin, and recombinant antibody techniques were used to create phage displayed libraries of variable region fragments of the heavy-chain antibodies. Caffeine-specific V(HH) fragments were selected by their ability to bind to caffeine/bovine serum albumin (BSA) and confirmed by a positive reaction in a caffeine enzyme-linked immunosorbent assay (caffeine ELISA). One of these V(HH) fragments (VSA2) was expressed as a soluble protein and shown to recover its reactivity after exposure to temperatures up to 90 degrees C. In addition, VSA2 was able to bind caffeine at 70 degrees C. A competition caffeine ELISA was developed for the measurement of caffeine in beverages, and concentrations of caffeine obtained for coffee, Coca-Cola Classic, and Diet Coke agreed well with high performance liquid chromatography (HPLC) determination and literature values. VSA2 showed minimal cross reactivity with structurally related methylxanthines.

A Study of Cross-linked Regions of Poly(Vinyl Alcohol) Gels by Small-Angle Neutron Scattering

NASA Astrophysics Data System (ADS)

Lawrence, Mathias B.; Desa, J. A. E.; Aswal, V. K.

2011-07-01

A poly(vinyl alcohol)-borax cross-linked hydrogel has been studied by Small Angle Neutron Scattering as a function of borax concentration in the wave-vector transfer (Q) range of 0.017 Å-1 to 0.36 Å-1. It is found that as the concentration of borax increases, so does the intensity of scattering in this range. Beyond a borax concentration of 2 mg/ml, the increase in cross-linked PVA chains leads to cross-linked units larger than 150 Å as evidenced by a reduction in intensity in the lower Q region.

cap alpha. -D-Mannopyranosylmethyl-P-nitrophenyltriazene effects on the degradation and biosynthesis of N-linked oligosaccharide chains on. cap alpha. /sub 1/-acid glycoprotein by liver cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Docherty, P.A.; Aronson, N.N. Jr.

1986-05-01

The effects of ..cap alpha..-D-mannopyranosylmethyl-p-nitrophenyltriazene (..cap alpha..-ManMNT) on the degradation and processing of oligosaccharide chains on ..cap alpha../sub 1/-acid glycoprotein (AGP) were studied. Addition of the triazene to a perfused liver blocked the complete degradation of endocytosed N-acetyl (/sup 14/C)glucosamine-labeled asialo-AGP and caused the accumulation of Man/sub 2/GlcNAc/sub 1/ fragments in the lysosome-enriched fraction of the liver homogenate. This compound also reduced the reincorporation of lysosomally-derived (/sup 14/C)GlcNAc into newly secreted glycoproteins. Cultured hepatocytes treated with the inhibitor synthesized and secreted fully-glycosylated AGP. However, the N-linked oligosaccharide chains on AGP secreted by the ..cap alpha..-ManMNT-treated hepatocytes remained sensitive to digestionmore » with endoglycosidase H, were resistant to neuraminidase, and consisted of Man/sub 9-7/GlcNAc/sub 2/ structures as analyzed by high resolution Bio-Gel P-4 chromatography. As measured by their resistance to cleavage by endoglycosidase H, the normal processing of all six carbohydrate chains on AGP to the complex form did not completely resume until nearly 24 h after triazene treatment. Since ManMNT is likely to irreversibly inactivate ..cap alpha..-D-mannosidases, the return of AGP to secretory forms with complex chains after 24 h probably resulted from synthesis of new processing enzymes.« less

Processing of N-linked oligosaccharides from precursor- to mature-form herpes simplex virus type 1 glycoprotein gC.

PubMed Central

Serafini-Cessi, F; Dall'Olio, F; Pereira, L; Campadelli-Fiume, G

1984-01-01

Immature and mature forms of glycoprotein gC were purified by immunoadsorbent from herpes simplex virus type 1-infected BHK cells labeled with [3H]mannose for a 20-min pulse or for 11 h followed by a 3-h chase. The nature of N-asparagine-linked oligosaccharides carried by the immature form, pgC (molecular weight = 92,000), and the mature gC (molecular weight = 120,000) has been investigated. All pronase-digested glycopeptides of pgC were susceptible to endo-beta-N-acetylglucosaminidase H treatment; thus they have a high-mannose structure. Using thin-layer chromatography to separate endo-beta-N-acetylglucosaminidase H-cleaved oligosaccharides, polymannosyl chains of different sizes, ranging from Man9GlcNAc to Man5GlcNAc, were separated. The major components were Man8GlcNAc and Man7GlcNAc, suggesting that pgC labeled in a 20-min pulse represents the form of glycoprotein already routed to the Golgi apparatus. Analysis of glycopeptides of mature gC showed that the majority (95%) of N-linked glycans were converted to complex-type glycans. Ion-exchange chromatography and affinity chromatography on concanavalin A-Sepharose and leucoagglutinin-agarose revealed that diantennary and triantennary glycans predominated, whereas tetrantennary chains were not present. Parts of the di- and triantennary chains were not fully sialylated. The high heterogeneity of complex-type chains found in mature gC may be related to the high number of N-glycosylation sites of the glycoprotein as predicted by DNA sequencing studies (Frink et al., J. Virol. 45:634-647, 1983). Images PMID:6088806

Private sector embedded water risk: Merging the corn supply chain network and regional watershed depletion

NASA Astrophysics Data System (ADS)

Kim, T.; Brauman, K. A.; Schmitt, J.; Goodkind, A. L.; Smith, T. M.

2016-12-01

Water scarcity in US corn farming regions is a significant risk consideration for the ethanol and meat production sectors, which comprise 80% of all US corn demand. Water supply risk can lead to effects across the supply chain, affecting annual corn yields. The purpose of our study is to assess the water risk to the US's most corn-intensive sectors and companies by linking watershed depletion estimates with corn production, linked to downstream companies through a corn transport model. We use a water depletion index as an improved metric for seasonal water scarcity and a corn sourcing supply chain model based on economic cost minimization. Water depletion was calculated as the fraction of renewable (ground and surface) water consumption, with estimates of more than 75% depletion on an annual average basis indicating a significant water risk. We estimated company water risk as the amount of embedded corn coming from three categories of water stressed counties. The ethanol sector had 3.1% of sourced corn grown from counties that were more than 75% depleted while the beef sector had 14.0%. From a firm perspective, Tyson, JBS, Cargill, the top three US corn demanding companies, had 4.5%, 9.6%, 12.8% of their sourced corn respectively, coming from watersheds that are more than 75% depleted. These numbers are significantly higher than the global average of 2.2% of watersheds being classified as more than 75% depleted. Our model enables corn using industries to evaluate their supply chain risk of water scarcity through modeling corn sourcing and watershed depletion, providing the private sector a new method for risk estimation. Our results suggest corn dependent industries are already linked to water scarcity risk in disproportionate amounts due to the spatial heterogeneity of corn sourcing and water scarcity.

GammaM23K, gammaM232K, and gammaL77K single substitutions in the TF1-ATPase lower ATPase activity by disrupting a cluster of hydrophobic side chains.

PubMed

Bandyopadhyay, Sanjay; Allison, William S

2004-07-27

In crystal structures of the bovine F(1)-ATPase (MF(1)), the side chains of gammaMet(23), gammaMet(232), and gammaLeu(77) interact in a cluster. Substitution of the corresponding residues in the alpha(3)beta(3)gamma subcomplex of TF(1) with lysine lowers the ATPase activity to 2.3, 11, and 15%, respectively, of that displayed by wild-type. In contrast, TF(1) subcomplexes containing the gammaM(23)C, gammaM(232)C, and gammaL(77)C substitutions display 36, 36, and 130%, respectively, of the wild-type ATPase activity. The ATPase activity of the gammaM(23)C/gammaM(232)C double mutant subcomplex is 36% that of the wild-type subcomplex before and after cross-linking the introduced cysteines, whereas the ATPase activity of the gammaM(23)C/L(77)C double mutant increased from 50 to 85% that of wild-type after cross-linking the introduced cysteines. Only beta-beta cross-links formed when the alpha(3)(betaE(395)C)(3)gammaM(23)C double mutant was inactivated with CuCl(2). The overall results suggest that the attenuated ATPase of the mutant subcomplexes containing the gammaM(23)K, gammaL(77)K, and gammaM(232)K substitutions is caused by disruption of the cluster of hydrophobic amino acid side chains and that the midregion of the coiled-coil comprised of the amino- and carboxyl-terminal alpha helices of the gamma subunit does not undergo unwinding or major displacement from the side chain of gammaLeu(77) during ATP-driven rotation of the gamma subunit.

Effects of Differential Reinforcement and Rules with Feedback on Preference for Choice and Verbal Reports

ERIC Educational Resources Information Center

Karsina, Allen; Thompson, Rachel H.; Rodriguez, Nicole M.; Vanselow, Nicholas R.

2012-01-01

We evaluated the effects of differential reinforcement and accurate verbal rules with feedback on the preference for choice and the verbal reports of 6 adults. Participants earned points on a probabilistic schedule by completing the terminal links of a concurrent-chains arrangement in a computer-based game of chance. In free-choice terminal links,…

The Weak Link HP-41C hand-held calculator program

Treesearch

Ross A. Phillips; Penn A. Peters; Gary D. Falk

1982-01-01

The Weak Link hand-held calculator program (HP-41C) quickly analyzes a system for logging production and costs. The production equations model conventional chain saw, skidder, loader, and tandemaxle truck operations in eastern mountain areas. Production of each function of the logging system may be determined so that the system may be balanced for minimum cost. The...

Accessible, almost ab initio multi-scale modeling of entangled polymers via slip-links

NASA Astrophysics Data System (ADS)

Andreev, Marat

It is widely accepted that dynamics of entangled polymers can be described by the tube model. Here we advocate for an alternative approach to entanglement modeling known as slip-links. Recently, slip-links were shown to possess important advantages over tube models, namely they have strong connections to atomistic, multichain levels of description, agree with non-equilibrium thermodynamics, are applicable to any chain architecture and can be used in linear or non-linear rheology. We present a hierarchy of slip-link models that are connected to each other through successive coarse graining. Models in the hierarchy are consistent in their overlapping domains of applicability in order to allow a straightforward mapping of parameters. In particular, the most--detailed level of description has four parameters, three of which can be determined directly from atomistic simulations. On the other hand, the least--detailed member of the hierarchy is numerically accessible, and allows for non-equilibrium flow predictions of complex chain architectures. Using GPU implementation these predictions can be obtained in minutes of computational time on a single desktop equipped with a mainstream gaming GPU. The GPU code is available online for free download.

Bifunctional Rhodamine Probes of Myosin Regulatory Light Chain Orientation in Relaxed Skeletal Muscle Fibers

PubMed Central

Brack, Andrew S.; Brandmeier, Birgit D.; Ferguson, Roisean E.; Criddle, Susan; Dale, Robert E.; Irving, Malcolm

2004-01-01

The orientation of the regulatory light chain (RLC) region of the myosin heads in relaxed skinned fibers from rabbit psoas muscle was investigated by polarized fluorescence from bifunctional rhodamine (BR) probes cross-linking pairs of cysteine residues introduced into the RLC. Pure 1:1 BR-RLC complexes were exchanged into single muscle fibers in EDTA rigor solution for 30 min at 30°C; ∼60% of the native RLC was removed and stoichiometrically replaced by BR-RLC, and >85% of the BR-RLC was located in the sarcomeric A-bands. The second- and fourth-rank order parameters of the orientation distributions of BR dipoles linking RLC cysteine pairs 100-108, 100-113, 108-113, and 104-115 were calculated from polarized fluorescence intensities, and used to determine the smoothest RLC orientation distribution—the maximum entropy distribution—consistent with the polarized fluorescence data. Maximum entropy distributions in relaxed muscle were relatively broad. At the peak of the distribution, the “lever” axis, linking Cys707 and Lys843 of the myosin heavy chain, was at 70–80° to the fiber axis, and the “hook” helix (Pro830–Lys843) was almost coplanar with the fiber and lever axes. The temperature and ionic strength of the relaxing solution had small but reproducible effects on the orientation of the RLC region. PMID:15041671

Stability of ecological industry chain: an entropy model approach.

PubMed

Wang, Qingsong; Qiu, Shishou; Yuan, Xueliang; Zuo, Jian; Cao, Dayong; Hong, Jinglan; Zhang, Jian; Dong, Yong; Zheng, Ying

2016-07-01

A novel methodology is proposed in this study to examine the stability of ecological industry chain network based on entropy theory. This methodology is developed according to the associated dissipative structure characteristics, i.e., complexity, openness, and nonlinear. As defined in the methodology, network organization is the object while the main focus is the identification of core enterprises and core industry chains. It is proposed that the chain network should be established around the core enterprise while supplementation to the core industry chain helps to improve system stability, which is verified quantitatively. Relational entropy model can be used to identify core enterprise and core eco-industry chain. It could determine the core of the network organization and core eco-industry chain through the link form and direction of node enterprises. Similarly, the conductive mechanism of different node enterprises can be examined quantitatively despite the absence of key data. Structural entropy model can be employed to solve the problem of order degree for network organization. Results showed that the stability of the entire system could be enhanced by the supplemented chain around the core enterprise in eco-industry chain network organization. As a result, the sustainability of the entire system could be further improved.

The effect of covalently linked RGD peptide on the conformation of polysaccharides in aqueous solutions.

PubMed

Bernstein-Levi, Ortal; Ochbaum, Guy; Bitton, Ronit

2016-01-01

Covalently modified polysaccharides are routinely used in tissue engineering due to their tailored biofunctionality. Understanding the effect of single-chain level modification on the solution conformation of the single chain, and more importantly on the self-assembly and aggregation of the ensemble of chains is expected to improve our ability to control network topology and the properties of the resulting gels. Attaching an RGD peptide to a polysaccharide backbone is a common procedure used to promote cell adhesion in hydrogel scaffolds. Recently it has been shown that the spatial presentation of the RGD sequences affects the cell behavior; thus, understanding the effects of grafted RGD on the conformational properties of the solvated polysaccharide chains is a prerequisite for rational design of polysaccharide-peptide based biomaterials. Here we investigate the effect of covalently linked G4RGDS on the conformational state of the individual chain and chain assemblies of alginate, chitosan, and hyaluronic acid (HA) in aqueous solutions. Two peptide fractions were studied using small-angle X-ray scattering (SAXS) and rheology. In all cases, upon peptide conjugation structural differences were observed. Analysis of the scattering data shows evidence of clustering for a higher fraction of bound peptide. Moreover for all three polysaccharides the typical shear thinning behavior of the natural polysaccharide solutions is replaced by a Newtonian fluid behavior for the lower fraction conjugated peptide while a more pronounced shear thinning behavior is observed for the higher fraction. These results indicate that the fraction of the bounded peptide, determines the behavior of a polysaccharide-peptide conjugates in solution, regardless of the specific nature of the polysaccharide. Copyright © 2015 Elsevier B.V. All rights reserved.

USP7 small-molecule inhibitors interfere with ubiquitin binding.

PubMed

Kategaya, Lorna; Di Lello, Paola; Rougé, Lionel; Pastor, Richard; Clark, Kevin R; Drummond, Jason; Kleinheinz, Tracy; Lin, Eva; Upton, John-Paul; Prakash, Sumit; Heideker, Johanna; McCleland, Mark; Ritorto, Maria Stella; Alessi, Dario R; Trost, Matthias; Bainbridge, Travis W; Kwok, Michael C M; Ma, Taylur P; Stiffler, Zachary; Brasher, Bradley; Tang, Yinyan; Jaishankar, Priyadarshini; Hearn, Brian R; Renslo, Adam R; Arkin, Michelle R; Cohen, Frederick; Yu, Kebing; Peale, Frank; Gnad, Florian; Chang, Matthew T; Klijn, Christiaan; Blackwood, Elizabeth; Martin, Scott E; Forrest, William F; Ernst, James A; Ndubaku, Chudi; Wang, Xiaojing; Beresini, Maureen H; Tsui, Vickie; Schwerdtfeger, Carsten; Blake, Robert A; Murray, Jeremy; Maurer, Till; Wertz, Ingrid E

2017-10-26

The ubiquitin system regulates essential cellular processes in eukaryotes. Ubiquitin is ligated to substrate proteins as monomers or chains and the topology of ubiquitin modifications regulates substrate interactions with specific proteins. Thus ubiquitination directs a variety of substrate fates including proteasomal degradation. Deubiquitinase enzymes cleave ubiquitin from substrates and are implicated in disease; for example, ubiquitin-specific protease-7 (USP7) regulates stability of the p53 tumour suppressor and other proteins critical for tumour cell survival. However, developing selective deubiquitinase inhibitors has been challenging and no co-crystal structures have been solved with small-molecule inhibitors. Here, using nuclear magnetic resonance-based screening and structure-based design, we describe the development of selective USP7 inhibitors GNE-6640 and GNE-6776. These compounds induce tumour cell death and enhance cytotoxicity with chemotherapeutic agents and targeted compounds, including PIM kinase inhibitors. Structural studies reveal that GNE-6640 and GNE-6776 non-covalently target USP7 12 Å distant from the catalytic cysteine. The compounds attenuate ubiquitin binding and thus inhibit USP7 deubiquitinase activity. GNE-6640 and GNE-6776 interact with acidic residues that mediate hydrogen-bond interactions with the ubiquitin Lys48 side chain, suggesting that USP7 preferentially interacts with and cleaves ubiquitin moieties that have free Lys48 side chains. We investigated this idea by engineering di-ubiquitin chains containing differential proximal and distal isotopic labels and measuring USP7 binding by nuclear magnetic resonance. This preferential binding protracted the depolymerization kinetics of Lys48-linked ubiquitin chains relative to Lys63-linked chains. In summary, engineering compounds that inhibit USP7 activity by attenuating ubiquitin binding suggests opportunities for developing other deubiquitinase inhibitors and may be a strategy more broadly applicable to inhibiting proteins that require ubiquitin binding for full functional activity.

A novel T cell receptor single-chain signaling complex mediates antigen-specific T cell activity and tumor control

PubMed Central

Stone, Jennifer D.; Harris, Daniel T.; Soto, Carolina M.; Chervin, Adam S.; Aggen, David H.; Roy, Edward J.; Kranz, David M.

2014-01-01

Adoptive transfer of genetically modified T cells to treat cancer has shown promise in several clinical trials. Two main strategies have been applied to redirect T cells against cancer: 1) introduction of a full-length T cell receptor (TCR) specific for a tumor-associated peptide-MHC, or 2) introduction of a chimeric antigen receptor (CAR), including an antibody fragment specific for a tumor cell surface antigen, linked intracellularly to T cell signaling domains. Each strategy has advantages and disadvantages for clinical applications. Here, we present data on the in vitro and in vivo effectiveness of a single-chain signaling receptor incorporating a TCR variable fragment as the targeting element (referred to as TCR-SCS). This receptor contained a single-chain TCR (Vβ-linker-Vα) from a high-affinity TCR called m33, linked to the intracellular signaling domains of CD28 and CD3ζ. This format avoided mispairing with endogenous TCR chains, and mediated specific T cell activity when expressed in either CD4 or CD8 T cells. TCR-SCS-transduced CD8-negative cells showed an intriguing sensitivity, compared to full-length TCRs, to higher densities of less stable pepMHC targets. T cells that expressed this peptide-specific receptor persisted in vivo, and exhibited polyfunctional responses. Growth of metastatic antigen-positive tumors was significantly inhibited by T cells that expressed this receptor, and tumor cells that escaped were antigen loss variants. TCR-SCS receptors represent an alternative targeting receptor strategy that combines the advantages of single-chain expression, avoidance of TCR chain mispairing, and targeting of intracellular antigens presented in complex with MHC proteins. PMID:25082071

Screening for X-linked adrenoleukodystrophy among adult men with Addison's disease.

PubMed

Horn, Morten A; Erichsen, Martina M; Wolff, Anette S B; Månsson, Jan-Eric; Husebye, Eystein S; Tallaksen, Chantal M E; Skjeldal, Ola H

2013-09-01

X-linked adrenoleukodystrophy is an important cause of Addison's disease in boys, but less is known about its contribution to Addison's disease in adult men. After surveying all known cases of X-linked adrenoleukodystrophy in Norway in a separate study, we aimed to look for any missed cases among the population of adult men with nonautoimmune Addison's disease. Among 153 adult men identified in a National Registry for Addison's Disease (75% of identified male cases of Addison's disease in Norway), those with negative indices for 21-hydroxylase autoantibodies were selected. Additionally, cases with low autoantibody indices (48-200) were selected. Sera from subjects included were analysed for levels of very long-chain fatty acids, which are diagnostic for X-linked adrenoleukodystrophy in men. Eighteen subjects had negative indices and 17 had low indices for 21-hydroxylase autoantibodies. None of those with low indices and only one of those with negative indices were found to have X-linked adrenoleukodystrophy; this subject had already been diagnosed because of the neurological symptoms. Cases of Addison's disease proved to be caused by X-linked adrenoleukodystrophy constitute 1·5% of all adult male cases in Norway; the proportion among nonautoimmune cases was 15%. We found X-linked adrenoleukodystrophy to be an uncommon cause of Addison's disease in adult men. However, this aetiological diagnosis has far-reaching consequences both for the patient and for his extended family. We therefore recommend that all adult men with nonautoimmune Addison's disease be analysed for levels of very long-chain fatty acids. © 2013 John Wiley & Sons Ltd.

A quantitative analysis of sensitivity to the conditioned reinforcing value of terminal-link stimuli in a concurrent-chains schedule.

PubMed Central

Omino, T

1993-01-01

Pigeons were exposed to a concurrent-chains schedule in which a single variable-interval 30-s schedule was used in the initial links and fixed-time schedules were used in the terminal links. Three types of keylight conditions were used in the terminal links. In the first condition, different delays were associated with different keylight stimuli (cued condition). In the second condition, different delays were associated with the same stimulus, either a blackout (uncued blackout condition) or a white key (uncued white condition). Paired values of terminal-link fixed-time schedules differed by a constant ratio of 3:1, while the absolute value of delays was varied from 3 s to 54 s. The results showed that choice proportions for the shorter of two delays increased when the absolute size of the delays was increased for all keylight conditions. Further, the choice proportions for the shorter delay increased from the uncued blackout condition, to the uncued white condition, to the cued condition. A modified version of Fantino's (1969) delay-reduction model (expressed as a function relating the response ratio to the delay-reduction ratio) can be applied to these data by showing that sensitivity to delay reduction increased from the uncued blackout condition, to the uncued white condition, to the cued condition. Thus, the present study demonstrated that a modified version of the delay-reduction model can be used to assess quantitative differences in the terminal-link keylight condition in terms of sensitivity to delay reduction (i.e., the conditioned reinforcing value of the terminal-link keylight stimuli). PMID:8283150

Ethyl 5-amino-1-[(4-methyl­phen­yl)sulfon­yl]-1H-pyrazole-4-carboxyl­ate

PubMed Central

Elgazwy, Abdel-Sattar S. Hamad; Nassar, Ibrahim F.; Jones, Peter G.

2013-01-01

In the title mol­ecule, C13H15N3O4S, the benzene and pyrazole rings are inclined to each other at 77.48 (3)°. Two amino H atoms are involved in bifurcated hydrogen bonds, viz. intra­molecular N—H⋯O and inter­molecular N—H⋯O(N). The inter­molecular hydrogen bonds link the mol­ecules related by translation in [100] into chains. A short distance of 3.680 (3) Å between the centroids of benzene and pyrazole rings from neighbouring mol­ecules shows the presence of π–π inter­actions, which link the hydrogen-bonded chains into layers parallel to the ab plane. PMID:24427020

Endoglycosidase and glycoamidase release of N-linked oligosaccharides.

PubMed

Freeze, Hudson H; Kranz, Christian

2006-09-01

Nearly all proteins entering the lumen of the endoplasmic reticulum (ER) become glycosylated en route to a cellular organelle, the plasma membrane, or the extracellular space. Many glycans can be attached to proteins, but the most common are the N-linked oligosaccharides. These chains are added very soon after a protein enters the ER, but they undergo extensive remodeling (processing), especially in the Golgi. Processing changes the sensitivity of the N-glycan to enzymes that cleave entire sugar chains or individual monosaccharides, which also changes the migration of the protein on SDS gels. These changes can be used to indicate when a protein has passed a particular subcellular location. This unit details some of the methods used to track a protein as it traffics from the ER to the Golgi toward its final location.

Ethyl 2-[(carbamothioyl­amino)­imino]­propano­ate

PubMed Central

Corrêa, Charlane C.; Graúdo, José Eugênio J.C.; de Oliveira, Luiz Fernando C.; de Almeida, Mauro V.; Diniz, Renata

2011-01-01

The title compound, C6H11N3O2S, consists of a roughly planar mol­ecule (r.m.s deviation from planarity = 0.077 Å for the non-H atoms) and has the S atom in an anti position to the imine N atom. This N atom is the acceptor of a strongly bent inter­nal N—H⋯N hydrogen bond donated by the amino group. In the crystal, mol­ecules are arranged in undulating layers parallel to (010). The mol­ecules are linked via inter­molecular amino–carboxyl N—H⋯O hydrogen bonds, forming chains parallel to [001]. The chains are cross-linked by Ncarbazone—H⋯S and C—H⋯S inter­actions, forming infinite sheets. PMID:22091006

Information flow and protein dynamics: the interplay between nuclear magnetic resonance spectroscopy and molecular dynamics simulations

PubMed Central

Pastor, Nina; Amero, Carlos

2015-01-01

Proteins participate in information pathways in cells, both as links in the chain of signals, and as the ultimate effectors. Upon ligand binding, proteins undergo conformation and motion changes, which can be sensed by the following link in the chain of information. Nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics (MD) simulations represent powerful tools for examining the time-dependent function of biological molecules. The recent advances in NMR and the availability of faster computers have opened the door to more detailed analyses of structure, dynamics, and interactions. Here we briefly describe the recent applications that allow NMR spectroscopy and MD simulations to offer unique insight into the basic motions that underlie information transfer within and between cells. PMID:25999971

Food handlers as a link in the chain of transmission of Giardia duodenalis and other protozoa in public schools in southern Brazil.

PubMed

Colli, Cristiane Maria; Bezagio, Renata Coltro; Nishi, Letícia; Ferreira, Érika Cristina; Falavigna-Guilherme, Ana Lúcia; Gomes, Mônica Lúcia

2015-09-01

Food handlers (FHs) may facilitate transmission and dissemination of pathogens. The importance of FHs as a link in the epidemiological chain of transmission of Giardia duodenalis and other intestinal protozoa was assessed. Fecal and subungual material from 27 FHs were analyzed using parasitological methods. G. duodenalis was identified by direct immunofluorescence and genotyped by PCR-RFLP for the bg and gdh genes, and gdh was sequenced. At least one protozoan was detected in 30% (8/27) of the FHs and G. duodenalis (19%; 5/27) was the most common species. The AII and BIV genotypes were found in 20% (1/5) and 60% (3/5) of FHs infected with G. duodenalis, respectively. FHs can be involved in the chain of transmission of G. duodenalis and other protozoa. KJ741310 - KJ741313. © The Author 2015. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Numerical modelling of new rockfall interception nets

NASA Astrophysics Data System (ADS)

von Boetticher, Albrecht; Volkwein, Axel; Wendeler, Corinna

2010-05-01

The design and certification of effective rockfall protection barriers is mainly achieved through 1:1 prototype testing. In order to reduce development costs of a prototype it is recommended that pre-studies using numerical simulations are performed. A large component to modelling rockfall protection systems is the numerical simulation of the nets. To date there exist several approaches to model the different mesh types such as ring nets or diagonal meshes (Nicot 1999, Cazzani et al. 2002, Volkwein 2004). However, the consideration of chain link meshes has not yet been realised. Chain link meshes are normally found as standard fence structures. However, they also exist in setups using high-strength steel and wire bundles. These variants show an enormous capacity to retain loads e.g. rockfalls, and at the same time are very efficient due to their low demand of steel material. The increasing application of chain link mesh in barrier systems requires an accurate model is available to complete prototype studies. A new approach now aims to perform a Finite Element simulation of such chain link meshes. The main challenge herein is to achieve the net deformation behaviour that is observed in field tests also in the simulation. A simulation using simple truss elements would not work since it neglects the out-of-plane-height of the mesh construction providing important reserves for local and global high deformations. Thus addressing this, a specially developed Discrete Element is able to reconstruct the mechanical behaviour of the single chain wire (bundles). As input parameters it utilises typical properties such as longitudinal and transversal mesh widths, and break loads resulting from in-plane-tension tests and steel strength. The single chain elements then can be combined to a complete mesh (e.g. 130 x 65 mm, 3 - 4 mm wire with a strength of 1770 N-mm2). Combining these elements with a supporting structure consisting of posts, ropes and energy absorbers, enables the simulation of protection barriers used for natural hazards such as rockfalls or even landslides. The contribution explains the mechanical behaviour of the chain mesh, the calibration procedures and their application in flexible rockfall protection systems. The investigated meshes are built using three or four millimeter wire with a minimum yield strength of 1770 N-mm2: The maximal load in longitudinal mesh direction ranges about 130 - 380 kN-m and transversal 50 - 170 kN-m. The mesh size varies from 83 × 143 mm to 292 × 500 mm. References Cazzani, A., Mongiovi, L. and Frenez, T. (2002) Dynamic Finite Element Analysis of Interceptive Devices for Falling Rocks, International Journal of Rock Mechanics & Mining Sciences. 39,303-321. Volkwein, A. (2004) Numerische Simulation von flexiblen Steinschlagschutzsystemen. Diss. ETH Nr. 15641. Nicot, F. (1999) Etude du comportement méchanique des ouvrages souples de protection contre les éboulements rocheux. Diss. Ecole Centrale de Lyon.

Cross-linking connectivity in bone collagen fibrils: the COOH-terminal locus of free aldehyde

NASA Technical Reports Server (NTRS)

Otsubo, K.; Katz, E. P.; Mechanic, G. L.; Yamauchi, M.

1992-01-01

Quantitative analyses of the chemical state of the 16c residue of the alpha 1 chain of bone collagen were performed on samples from fetal (4-6-month embryo) and mature (2-3 year old) bovine animals. All of this residue could be accounted for in terms of three chemical states, in relative amounts which depended upon the age of the animal. Most of the residue was incorporated into either bifunctional or trifunctional cross-links. Some of it, however, was present as free aldehyde, and the content increased with maturation. This was established by isolating and characterizing the aldehyde-containing peptides generated by tryptic digestion of NaB3H4-reduced mature bone collagen. We have concluded that the connectivity of COOH-terminal cross-linking in bone collagen fibrils changes with maturation in the following way: at first, each 16c residue in each of the two alpha 1 chains of the collagen molecule is incorporated into a sheet-like pattern of intermolecular iminium cross-links, which stabilizes the young, nonmineralized fibril as a whole. In time, some of these labile cross-links maturate into pyridinoline while others dissociate back to their precursor form. The latter is likely due to changes in the molecular packing brought about by the mineralization of the collagen fibrils. The resultant reduction in cross-linking connectivity may provide a mechanism for enhancing certain mechanical characteristics of the skeleton of a mature animal.

Cloning and sequence analysis of complementary DNA encoding an aberrantly rearranged human T-cell gamma chain.

PubMed Central

Dialynas, D P; Murre, C; Quertermous, T; Boss, J M; Leiden, J M; Seidman, J G; Strominger, J L

1986-01-01

Complementary DNA (cDNA) encoding a human T-cell gamma chain has been cloned and sequenced. At the junction of the variable and joining regions, there is an apparent deletion of two nucleotides in the human cDNA sequence relative to the murine gamma-chain cDNA sequence, resulting simultaneously in the generation of an in-frame stop codon and in a translational frameshift. For this reason, the sequence presented here encodes an aberrantly rearranged human T-cell gamma chain. There are several surprising differences between the deduced human and murine gamma-chain amino acid sequences. These include poor homology in the variable region, poor homology in a discrete segment of the constant region precisely bounded by the expected junctions of exon CII, and the presence in the human sequence of five potential sites for N-linked glycosylation. Images PMID:3458221

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harstad, E. N.; Harlow, Francis Harvey,; Schreyer, H. L.

Our goal is to develop constitutive relations for the behavior of a solid polymer during high-strain-rate deformations. In contrast to the classic thermodynamic techniques for deriving stress-strain response in static (equilibrium) circumstances, we employ a statistical-mechanics approach, in which we evolve a probability distribution function (PDF) for the velocity fluctuations of the repeating units of the chain. We use a Langevin description for the dynamics of a single repeating unit and a Lioville equation to describe the variations of the PDF. Moments of the PDF give the conservation equations for a single polymer chain embedded in other similar chains. Tomore » extract single-chain analytical constitutive relations these equations have been solved for representative loading paths. By this process we discover that a measure of nonuniform chain link displacement serves this purpose very well. We then derive an evolution equation for the descriptor function, with the result being a history-dependent constitutive relation.« less

Very Long Chain Fatty Acids Are Functionally Involved in Necroptosis.

PubMed

Parisi, Laura R; Li, Nasi; Atilla-Gokcumen, G Ekin

2017-12-21

Necroptosis is a form of regulated cell death that is linked to various human diseases. Distinct membrane-related, thus lipid-dependent, alterations take place during necroptosis. However, little is known about the roles of specific lipids in this process. We used an untargeted LC-MS-based approach to reveal that distinct lipid species are regulated at the molecular level during necroptosis. We found that ceramides and very long chain fatty acids accumulate during this process. Intrigued by the specificity of very long chain fatty acid accumulation, we focused on characterizing their involvement during necroptosis. Biochemical characterizations suggested that activated fatty acid biosynthesis and elongation could be responsible for these accumulations. We further showed that inhibition of fatty acid biosynthesis and depletion of very long chain fatty acids prevented loss of plasma membrane integrity and cell death, strongly suggesting that very long chain fatty acids are functionally involved in necroptosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

J chain in the nurse shark: implications for function in a lower vertebrate.

PubMed

Hohman, Valerie S; Stewart, Sue E; Rumfelt, Lynn L; Greenberg, Andrew S; Avila, David W; Flajnik, Martin F; Steiner, Lisa A

2003-06-15

J chain is a small polypeptide covalently attached to polymeric IgA and IgM. In humans and mice, it plays a role in binding Ig to the polymeric Ig receptor for transport into secretions. The putative orthologue of mammalian J chain has been identified in the nurse shark by sequence analysis of cDNA and the polypeptide isolated from IgM. Conservation with J chains from other species is relatively poor, especially in the carboxyl-terminal portion, and, unlike other J chains, the shark protein is not acidic. The only highly conserved segment in all known J chains is a block of residues surrounding an N-linked glycosylation site. Of the eight half-cystine residues that are conserved in mammalian J chains, three are lacking in the nurse shark, including two in the carboxyl-terminal segment that have been reported to be required for binding of human J chain-containing IgA to secretory component. Taken together with these data, the relative abundance of J chain transcripts in the spleen and their absence in the spiral valve (intestine) suggest that J chain in nurse sharks may not have a role in Ig secretion. Analysis of J chain sequences in diverse species is in agreement with accepted phylogenetic relationships, with the exception of the earthworm, suggesting that the reported presence of J chain in invertebrates should be reassessed.

A Bullet-Block Experiment that Explains the Chain Fountain

NASA Astrophysics Data System (ADS)

Pantaleone, J.; Smith, R.

2018-05-01

It is common in science for two phenomena to appear to be very different, but in fact follow from the same basic principles. Here we consider such a case, the connection between the chain fountain and a bullet-block collision experiment. When an upward moving bullet strikes a wooden block resting on a horizontal table, the block will rise to a higher height when the bullet strikes near the end of the block. This is because the quickly rotating block experiences an additional upward "reaction" force from its contact with the table. Such a reaction force also explains the chain fountain. When a chain falls from a pile in a container to the floor below, the chain rises up above the container. This rise occurs because the quickly rotating links in the container push off of the surface beneath them. We derive a model that accurately describes our measurements in the bullet-block experiment, and then use this same model to calculate an approximate expression for the distance the chain rises above the container. More extensive discussions of the chain fountain are available elsewhere.

Closed loop supply chain network design with fuzzy tactical decisions

NASA Astrophysics Data System (ADS)

Sherafati, Mahtab; Bashiri, Mahdi

2016-09-01

One of the most strategic and the most significant decisions in supply chain management is reconfiguration of the structure and design of the supply chain network. In this paper, a closed loop supply chain network design model is presented to select the best tactical and strategic decision levels simultaneously considering the appropriate transportation mode in activated links. The strategic decisions are made for a long term; thus, it is more satisfactory and more appropriate when the decision variables are considered uncertain and fuzzy, because it is more flexible and near to the real world. This paper is the first research which considers fuzzy decision variables in the supply chain network design model. Moreover, in this study a new fuzzy optimization approach is proposed to solve a supply chain network design problem with fuzzy tactical decision variables. Finally, the proposed approach and model are verified using several numerical examples. The comparison of the results with other existing approaches confirms efficiency of the proposed approach. Moreover the results confirms that by considering the vagueness of tactical decisions some properties of the supply chain network will be improved.

Resistance to Change and Preference for Variable versus Fixed Response Sequences

ERIC Educational Resources Information Center

Arantes, Joana; Berg, Mark E.; Le, Dien; Grace, Randolph C.

2012-01-01

In Experiment 1, 4 pigeons were trained on a multiple chain schedule in which the initial link was a variable-interval (VI) 20-s schedule signalled by a red or green center key, and terminal links required four responses made to the left (L) and/or right (R) keys. In the REPEAT component, signalled by red keylights, only LRLR terminal-link…

A Complex Interplay among the Parent-Child Relationship, Effortful Control, and Internalized, Rule-Compatible Conduct in Young Children: Evidence from Two Studies

ERIC Educational Resources Information Center

Kochanska, Grazyna; Kim, Sanghag

2014-01-01

We propose a model linking the early parent-child mutually responsive orientation (MRO), children's temperament trait of effortful control, and their internalization of conduct rules. In a developmental chain, effortful control was posited as a mediator of the links between MRO and children's internalization. MRO was further posited as a moderator…

Identification of the antigenic determinants of factors 8, 9, and 34 of genus Candida.

PubMed

Kobayashi, H; Oyamada, H; Suzuki, A; Shibata, N; Suzuki, S; Okawa, Y

1996-10-21

We investigated the antigenic determinants of factors 8, 9, and 34 of the genus Candida among pathogenic yeasts by enzyme-linked immunosorbent assay (ELISA) using mannans of Saccharomyces cerevisiae wild type and mutant types, mnn 1-mnn 4 and mnn 2. Results of ELISA including antisera against the antigenic factors of genus Candida (Candida Check, latron; FAbs) indicated that these three types of mannan distinctly react with FAbs 34, 8 and 9, respectively. To identify the recognition sites of these FAbs, we compared the ability of various oligosaccharides to inhibit the binding of the mannans to FAbs. The results indicated that FAb 34 preferentially recognizes linear side chains containing a non-reducing terminal alpha-1,3-linked mannose residue, Man(alpha)1 --> 3Man(alpha)1 --> (2Man(alpha)1 --> )n(2Man) (n > or = 0), and that one of the recognition sites of FAb 9 is linear alpha-1,6-linked oligomannosyl series, Man(alpha)1 --> (6Man(alpha)1 --> )n(6Man) (n > or = 2). On the other hand, the recognition site of FAb 8 apparently consisted of two alpha-1,2-linked oligomannosyl side chains and an alpha-1,6-linked mannose residue that originated from the mannan backbone, Man(alpha)1 --> 2Man(alpha)1 --> 2(Man(alpha)1 -->2Man(alpha)1 --> 6)Man.

Density functional theory with van der waals corrections study of the adsorption of alkyl, alkylthiol, alkoxyl, and amino-alkyl chains on the H:Si(111) surface.

PubMed

Arefi, Hadi H; Nolan, Michael; Fagas, Giorgos

2014-11-11

Surface modification of silicon with organic monolayers tethered to the surface by different linkers is an important process in realizing future miniaturized electronic and sensor devices. Understanding the roles played by the nature of the linking group and the chain length on the adsorption structures and stabilities of these assemblies is vital to advance this technology. This paper presents a density functional theory (DFT) study of the hydrogen passivated Si(111) surface modified with alkyl chains of the general formula H:Si-(CH2)n-CH2 and H:Si-X-(CH2)n-CH3, where X = NH, O, S and n = (0, 1, 3, 5, 7, 9, 11), at half coverage. For (X)-hexane and (X)-dodecane functionalization, we also examined various coverages up to full monolayer grafting in order to validate the result of half covered surface and the linker effect on the coverage. We find that it is necessary to take into account the van der Waals interaction between the alkyl chains. The strongest binding is for the oxygen linker, followed by S, N, and C, irrespective of chain length. The result revealed that the sequence of the stability is independent of coverage; however, linkers other than carbon can shift the optimum coverage considerably and allow further packing density. For all linkers apart from sulfur, structural properties, in particular, surface-linker-chain angles, saturate to a single value once n > 3. For sulfur, we identify three regimes, namely, n = 0-3, n = 5-7, and n = 9-11, each with its own characteristic adsorption structures. Where possible, our computational results are shown to be consistent with the available experimental data and show how the fundamental structural properties of modified Si surfaces can be controlled by the choice of linking group and chain length.

29 CFR 1917.41 - House falls.

Code of Federal Regulations, 2014 CFR

2014-07-01

... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles, swivels, blocks and other loose gear used in house fall operations before each day's use. Defective gear shall not...

29 CFR 1917.41 - House falls.

Code of Federal Regulations, 2010 CFR

2010-07-01

... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles, swivels, blocks and other loose gear used in house fall operations before each day's use. Defective gear shall not...

29 CFR 1917.41 - House falls.

Code of Federal Regulations, 2011 CFR

2011-07-01

... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles, swivels, blocks and other loose gear used in house fall operations before each day's use. Defective gear shall not...

29 CFR 1917.41 - House falls.

Code of Federal Regulations, 2012 CFR

2012-07-01

... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles, swivels, blocks and other loose gear used in house fall operations before each day's use. Defective gear shall not...

29 CFR 1917.41 - House falls.

Code of Federal Regulations, 2013 CFR

2013-07-01

... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles, swivels, blocks and other loose gear used in house fall operations before each day's use. Defective gear shall not...

Solid polymeric electrolytes for lithium batteries

DOEpatents

Angell, Charles A.; Xu, Wu; Sun, Xiaoguang

2006-03-14

Novel conductive polyanionic polymers and methods for their preparion are provided. The polyanionic polymers comprise repeating units of weakly-coordinating anionic groups chemically linked to polymer chains. The polymer chains in turn comprise repeating spacer groups. Spacer groups can be chosen to be of length and structure to impart desired electrochemical and physical properties to the polymers. Preferred embodiments are prepared from precursor polymers comprising the Lewis acid borate tri-coordinated to a selected ligand and repeating spacer groups to form repeating polymer chain units. These precursor polymers are reacted with a chosen Lewis base to form a polyanionic polymer comprising weakly coordinating anionic groups spaced at chosen intervals along the polymer chain. The polyanionic polymers exhibit high conductivity and physical properties which make them suitable as solid polymeric electrolytes in lithium batteries, especially secondary lithium batteries.

Processing of MOPC 315 immunoglobulin A oligosaccharides: evidence for endoplasmic reticulum and trans Golgi alpha 1,2-mannosidase activity

PubMed Central

1984-01-01

The processing of asparagine-linked oligosaccharides on the alpha- chains of an immunoglobulin A (IgA) has been investigated using MOPC 315 murine plasmacytoma cells. These cells secrete IgA containing complex-type oligosaccharides that were not sensitive to endo-beta-N- acetylglucosaminidase H. In contrast, oligosaccharides present on the intracellular alpha-chain precursor were of the high mannose-type, remaining sensitive to endo-beta-N-acetylglucosaminidase H despite a long intracellular half-life of 2-3 h. The major [3H]mannose-labeled alpha-chain oligosaccharides identified after a 20-min pulse were Man8GlcNAc2 and Man9GlcNAc2. Following chase incubations, the major oligosaccharide accumulating intracellularly was Man6GlcNAc2, which was shown to contain a single alpha 1,2-linked mannose residue. Conversion of Man6GlcNAc2 to complex-type oligosaccharides occurred at the time of secretion since appreciable amounts of Man5GlcNAc2 or further processed structures could not be detected intracellularly. The subcellular locations of the alpha 1,2-mannosidase activities were studied using carbonyl cyanide m-chlorophenylhydrazone and monensin. Despite inhibiting the secretion of IgA, these inhibitors of protein migration did not effect the initial processing of Man9GlcNAc2 to Man6GlcNAc2. Furthermore, no large accumulation of Man5GlcNAc2 occurred, indicating the presence of two subcellular locations of alpha 1,2-mannosidase activity involved in oligosaccharide processing in MOPC 315 cells. Thus, the first three alpha 1,2-linked mannose residues were removed shortly after the alpha-chain was glycosylated, most likely in rough endoplasmic reticulum, since this processing occurred in the presence of carbonyl cyanide m-chlorophenylhydrazone. However, the removal of the final alpha 1,2-linked mannose residue as well as subsequent carbohydrate processing occurred just before IgA secretion, most likely in the trans Golgi complex since processing of Man6GlcNAc2 to Man5GlcNAc2 was greatly inhibited in the presence of monensin. PMID:6420419

Processing of MOPC 315 immunoglobulin A oligosaccharides: evidence for endoplasmic reticulum and trans Golgi alpha 1,2-mannosidase activity.

PubMed

Hickman, S; Theodorakis, J L; Greco, J M; Brown, P H

1984-02-01

The processing of asparagine-linked oligosaccharides on the alpha-chains of an immunoglobulin A (IgA) has been investigated using MOPC 315 murine plasmacytoma cells. These cells secrete IgA containing complex-type oligosaccharides that were not sensitive to endo-beta-N-acetylglucosaminidase H. In contrast, oligosaccharides present on the intracellular alpha-chain precursor were of the high mannose-type, remaining sensitive to endo-beta-N-acetylglucosaminidase H despite a long intracellular half-life of 2-3 h. The major [3H]mannose-labeled alpha-chain oligosaccharides identified after a 20-min pulse were Man8GlcNAc2 and Man9GlcNAc2. Following chase incubations, the major oligosaccharide accumulating intracellularly was Man6GlcNAc2, which was shown to contain a single alpha 1,2-linked mannose residue. Conversion of Man6GlcNAc2 to complex-type oligosaccharides occurred at the time of secretion since appreciable amounts of Man5GlcNAc2 or further processed structures could not be detected intracellularly. The subcellular locations of the alpha 1,2-mannosidase activities were studied using carbonyl cyanide m-chlorophenylhydrazone and monensin. Despite inhibiting the secretion of IgA, these inhibitors of protein migration did not effect the initial processing of Man9GlcNAc2 to Man6GlcNAc2. Furthermore, no large accumulation of Man5GlcNAc2 occurred, indicating the presence of two subcellular locations of alpha 1,2-mannosidase activity involved in oligosaccharide processing in MOPC 315 cells. Thus, the first three alpha 1,2-linked mannose residues were removed shortly after the alpha-chain was glycosylated, most likely in rough endoplasmic reticulum, since this processing occurred in the presence of carbonyl cyanide m-chlorophenylhydrazone. However, the removal of the final alpha 1,2-linked mannose residue as well as subsequent carbohydrate processing occurred just before IgA secretion, most likely in the trans Golgi complex since processing of Man6GlcNAc2 to Man5GlcNAc2 was greatly inhibited in the presence of monensin.

On the computer analysis of structures and mechanical systems

NASA Technical Reports Server (NTRS)

Bennett, B. E.

1984-01-01

The governing equations for the analysis of open branch-chain mechanical systems are developed in a form suitable for implementation in a general purpose finite element computer program. Lagrange's form of d'Alembert's principle is used to derive the system mass matrix and force vector. The generalized coordinates are selected as the unconstrained relative degrees of freedom giving the position and orientation of each slave link with respect to their master link. Each slave link may have from zero to six degrees of freedom relative to the reference frames of its master link. A strategy for automatic generation of the system mass matrix and force vector is described.

A Novel Mutation in the XLRS1 Gene in a Korean Family with X-linked Retinoschisis

PubMed Central

Jwa, Nam Soo; Kim, Sung Soo; Lee, Sung Chul; Kwon, Oh Woong

2006-01-01

Purpose To report a novel missense mutation in the XLRS1 gene in a Korean family with X-linked retinoschisis. Methods Observation case report of a family with a proband with X-linked retinoschisis underwent complete ophthalmologic examination. Genomic DNA was excluded from the family's blood and all exons of the XLRS1 gene were amplified by polymerase chain reaction and analyzed using a direct sequencing method. Results A novel Leu103Phe missense mutation was identified. Conclusions A novel Leu103Phe mutation is an additional missense mutation which is responsible for the pathogenesis of X-linked retinoschisis. PMID:16768192

Chain Dynamics in Magnetorheological Suspensions

NASA Technical Reports Server (NTRS)

Gast, A. P.; Furst, E. M.

1999-01-01

Magnetorheological (MR) suspensions are composed of colloidal particles which acquire dipole moments when subjected to an external magnetic field. At sufficient field strengths and concentrations, the dipolar particles rapidly aggregate to form long chains. Subsequent lateral cross-linking of the dipolar chains is responsible for a rapid liquid-to-solid-like rheological transition. The unique, magnetically-activated rheological properties of MR suspensions make them ideal for interfacing mechanical systems to electronic controls. Additionally, the ability to experimentally probe colloidal suspensions interacting through tunable anisotropic potentials is of fundamental interest. Our current experimental work has focused on understanding the fluctuations of dipolar chains. It has been proposed by Halsey and Toor (HT) that the strong Landau-Peierls thermal fluctuations of dipolar chains could be responsible for long-range attractions between chains. Such interactions will govern the long-time relaxation of MR suspensions. We have synthesized monodisperse neutrally buoyant MR suspensions by density matching stabilized ferrofluid emulsion droplets with D2O. This allows us to probe the dynamics of the dipolar chains using light scattering without gravitational, interfacial, and polydispersity effects to resolve the short-wavelength dynamics of the dipolar chains. We used diffusing wave spectroscopy to measure these dynamics. The particle displacements at short times that show an independence to the field strength, but at long times exhibit a constrained, sub-diffusive motion that slows as the dipole strength is increased. The experiments are in good qualitative agreement with Brownian dynamics simulations of dipolar chains. Although there have been several important and detailed studies of the structure and interactions in MR suspensions, there has not been conclusive evidence that supports or contradicts the HT model prediction that long-range interactions exist between fluctuating chains of dipolar particles. Resolving this issue would contribute greatly to the understanding of these interesting and important materials. We have begun to test the predictions of the HT model by both examining the dynamics of individual chains and by measuring the forces between dipolar chains directly to accurately and quantitatively assess the interactions that they experience. To do so, we employ optical trapping techniques and video-microscopy to manipulate and observe our samples on the microscopic level. With these techniques, it is possible to observe chains that are fluctuating freely in three-dimensions, independent of interfacial effects. More importantly, we are able to controllably observe the interactions of two chains at various separations to measure the force-distance profile. The techniques also allow us to study the mechanical properties of individual chains and chain clusters. Our work to this point has focused on reversibly-formed dipolar chains due to field induced dipoles where the combination of this chaining, the dipolar forces, and the hydrodynamic interactions that dictate the rheology of the suspensions. One can envision, however, many situations where optical, electronic, or rheological behavior may be optimized with magneto-responsive anisotropic particles. Chains of polarizable particles may have the best properties as they can coil and flex in the absence of a field and stiffen and orient when a field is applied. We have recently demonstrated a synthesis of stable, permanent paramagnetic chains by both covalently and physically linking paramagnetic colloidal particles. The method employed allows us to create monodisperse chains of controlled length. We observed the stability, field-alignment, and rigidity of this new class of materials. The chains may exhibit unique rheological properties in an applied magnetic field over isotropic suspensions of paramagnetic particles. They are also useful rheological models as bead-spring systems. These chains form the basis for our current experiments with optical traps.

Assessing the influence of side-chain and main-chain aromatic benzyltrimethyl ammonium on anion exchange membranes.

PubMed

Li, Xiuhua; Nie, Guanghui; Tao, Jinxiong; Wu, Wenjun; Wang, Liuchan; Liao, Shijun

2014-05-28

3,3'-Di(4″-methyl-phenyl)-4,4'-difluorodiphenyl sulfone (DMPDFPS), a new monomer with two pendent benzyl groups, was easily prepared by Suzuki coupling reaction in high yield. A series of side-chain type ionomers (PAES-Qs) containing pendant side-chain benzyltrimethylammonium groups, which linked to the backbone by alkaline resisting conjugated C-C bonds, were synthesized via polycondensation, bromination, followed by quaternization and alkalization. To assess the influence of side-chain and main-chain aromatic benzyltrimethylammonium on anion exchange membranes (AEMs), the main-chain type ionomers (MPAES-Qs) with the same backbone were synthesized following the similar procedure. GPC and (1)H NMR results indicate that the bromination shows no reaction selectivity of polymer configurations and ionizations of the side-chain type polymers display higher conversions than that of the main-chain type ones do. These two kinds of AEMs were evaluated in terms of ion exchange capacity (IEC), water uptake, swelling ratio, λ, volumetric ion exchange capacity (IECVwet), hydroxide conductivity, mechanical and thermal properties, and chemical stability, respectively. The side-chain type structure endows AEMs with lower water uptake, swelling ratio and λ, higher IECVwet, much higher hydroxide conductivity, more robust dimensional stability, mechanical and thermal properties, and higher stability in hot alkaline solution. The side-chain type cationic groups containing molecular configurations have the distinction of being practical AEMs and membrane electrode assemblies of AEMFCs.

Shape-Memory Hydrogels: Evolution of Structural Principles To Enable Shape Switching of Hydrophilic Polymer Networks.

PubMed

Löwenberg, Candy; Balk, Maria; Wischke, Christian; Behl, Marc; Lendlein, Andreas

2017-04-18

The ability of hydrophilic chain segments in polymer networks to strongly interact with water allows the volumetric expansion of the material and formation of a hydrogel. When polymer chain segments undergo reversible hydration depending on environmental conditions, smart hydrogels can be realized, which are able to shrink/swell and thus alter their volume on demand. In contrast, implementing the capacity of hydrogels to switch their shape rather than volume demands more sophisticated chemical approaches and structural concepts. In this Account, the principles of hydrogel network design, incorporation of molecular switches, and hydrogel microstructures are summarized that enable a spatially directed actuation of hydrogels by a shape-memory effect (SME) without major volume alteration. The SME involves an elastic deformation (programming) of samples, which are temporarily fixed by reversible covalent or physical cross-links resulting in a temporary shape. The material can reverse to the original shape when these molecular switches are affected by application of a suitable stimulus. Hydrophobic shape-memory polymers (SMPs), which are established with complex functions including multiple or reversible shape-switching, may provide inspiration for the molecular architecture of shape-memory hydrogels (SMHs), but cannot be identically copied in the world of hydrophilic soft materials. For instance, fixation of the temporary shape requires cross-links to be formed also in an aqueous environment, which may not be realized, for example, by crystalline domains from the hydrophilic main chains as these may dissolve in presence of water. Accordingly, dual-shape hydrogels have evolved, where, for example, hydrophobic crystallizable side chains have been linked into hydrophilic polymer networks to act as temperature-sensitive temporary cross-links. By incorporating a second type of such side chains, triple-shape hydrogels can be realized. Considering the typically given light permeability of hydrogels and the fully hydrated state with easy permeation by small molecules, other types of stimuli like light, pH, or ions can be employed that may not be easily used in hydrophobic SMPs. In some cases, those molecular switches can respond to more than one stimulus, thus increasing the number of opportunities to induce actuation of these synthetic hydrogels. Beyond this, biopolymer-based hydrogels can be equipped with a shape switching function when facilitating, for example, triple helix formation in proteins or ionic interactions in polysaccharides. Eventually, microstructured SMHs such as hybrid or porous structures can combine the shape-switching function with an improved performance by helping to overcome frequent shortcomings of hydrogels such as low mechanical strength or volume change upon temporary cross-link cleavage. Specifically, shape switching without major volume alteration is possible in porous SMHs by decoupling small volume changes of pore walls on the microscale and the macroscopic sample size. Furthermore, oligomeric rather than short aliphatic side chains as molecular switches allow stabilization of the sample volumes. Based on those structural principles and switching functionalities, SMHs have already entered into applications as soft actuators and are considered, for example, for cell manipulation in biomedicine. In the context of those applications, switching kinetics, switching forces, and reversibility of switching are aspects to be further explored.

Efficient sampling of reversible cross-linking polymers: Self-assembly of single-chain polymeric nanoparticles

NASA Astrophysics Data System (ADS)

Oyarzún, Bernardo; Mognetti, Bortolo Matteo

2018-03-01

We present a new simulation technique to study systems of polymers functionalized by reactive sites that bind/unbind forming reversible linkages. Functionalized polymers feature self-assembly and responsive properties that are unmatched by the systems lacking selective interactions. The scales at which the functional properties of these materials emerge are difficult to model, especially in the reversible regime where such properties result from many binding/unbinding events. This difficulty is related to large entropic barriers associated with the formation of intra-molecular loops. In this work, we present a simulation scheme that sidesteps configurational costs by dedicated Monte Carlo moves capable of binding/unbinding reactive sites in a single step. Cross-linking reactions are implemented by trial moves that reconstruct chain sections attempting, at the same time, a dimerization reaction between pairs of reactive sites. The model is parametrized by the reaction equilibrium constant of the reactive species free in solution. This quantity can be obtained by means of experiments or atomistic/quantum simulations. We use the proposed methodology to study the self-assembly of single-chain polymeric nanoparticles, starting from flexible precursors carrying regularly or randomly distributed reactive sites. We focus on understanding differences in the morphology of chain nanoparticles when linkages are reversible as compared to the well-studied case of irreversible reactions. Intriguingly, we find that the size of regularly functionalized chains, in good solvent conditions, is non-monotonous as a function of the degree of functionalization. We clarify how this result follows from excluded volume interactions and is peculiar of reversible linkages and regular functionalizations.

C5H9N isomers: pointers to possible branched chain interstellar molecules

NASA Astrophysics Data System (ADS)

Etim, Emmanuel E.; Gorai, Prasanta; Das, Ankan; Arunan, Elangannan

2017-04-01

The astronomical observation of isopropyl cyanide further stresses the link between the chemical composition of the interstellar medium (ISM) and molecular composition of the meteorites in which there is a dominance of branched chain amino acids as compared to the straight. However, observations of more branched chain molecules in ISM will firmly establish this link. In the light of this, we have considered C5H9N isomeric group in which the next higher member of the alkyl cyanide and other branched chain isomers belong. High-level quantum chemical calculations have been employed in estimating accurate energies of these isomers. From the results, the only isomer of the group that has been astronomically searched, n-butyl cyanide is not the most stable isomer and therefore, which might explain why its search could only yield upper limits of its column density without a successful detection. Rather, the two most stable isomers of the group are the branched chain isomers; tert-butylnitrile and isobutyl cyanide. Based on the rotational constants of these isomers, it is found that the expected intensity of tert-butylnitrile is the maximum among this isomeric group. Thus, this is proposed as the most probable candidate for astronomical observation. A simple LTE (local thermodynamic equilibrium) modelling has also been carried out to check the possibility of detecting tert-butyl cyanide in the millimetre-wave region. Contribution to the Topical Issue "Low-Energy Interactions related to Atmospheric and Extreme Conditions", edited by S. Ptasinska, M. Smialek-Telega, A. Milosavljevic and B. Sivaraman.

Computer Simulations of Bottle Brushes: From Melts to Soft Networks

DOE PAGES

Cao, Zhen; Carrillo, Jan-Michael Y.; Sheiko, Sergei S.; ...

2015-07-13

We use a combination of Molecular dynamics simulations and analytical calculations, and study dens bottle-brush systems in a melt and network State. Analysis of our simulation results shows that bottle-brush macromolecules in melt behave as ideal chains with effective Kuhn length b K. Simulations show that the bottle-brush-induced bending rigidity is due to an entropy decrease caused by redistribution of the side chains upon backbone bending. The Kuhn length of the bottle:brushes increases with increasing the side-chain degree of polymerization n sc as b K proportional to n sc 0.46. Moreover, this model of bottle brush macromolecules is extended tomore » describe mechanical properties of bottle brush networks in linear and nonlinear deformation regimes. In the linear deformation regime, the network shear modulus scales with the degree of polymerization of the side chains as G 0 proportional to (n sc + 1) -1 as long as the ratio of the Kuhn length, b K, to the size of the fully extended bottle-brush backbone between cross-links, R-max, is smaller than unity, b K/R max << 1. Bottle-brush networks With b K/R max proportional to 1 demonstrate behavior similar to that of networks Of semiflexible chains with G 0 proportional to n sc -0.5. Finally, in the nonlinear network deformation regime, the deformation-dependent shear modulus is a universal function of the first strain invariant I 1 and bottle-brush backbone deformation ratio beta describing stretching ability of the bottle-brush backbone between cross-links.« less

Steel Sea-Going Ship Construction Standards (Kang-chih Hai-ch’uan Chien-tsao Kuei-fan).

DTIC Science & Technology

1978-03-06

decozh lessthn5, ehto-aerolnabeth deck may be 2.-,;e he deo)th. (2) Flushing T.o.sts s.o Ad binocrae -’tth fdlowin re: (1)Mei*htfro td te~in: sot o...dieter d z , 4bD -53 m, it shou!d not be exceeding 1.5 :mm; -,,ihen chain diameter d,: 57 :-.n, it should not exceed 2 . Th. welded chains and links and

catena-Poly[[[4,6-bis-(2-pyrid-yl)-1,3,5-triazin-2-olato]copper(II)]-μ-chlorido].

PubMed

Cao, Man-Li

2011-06-01

The title compound, [Cu(C(13)H(8)N(5)O)Cl](n), has a chain structure parallel to [100] with Cu(2+) cations in a trigonal-bipyramidal coordination environment. The ligand adopts a tridentate tripyridyl coordination mode and a chloride ion acts as a bridge. The chains are linked via weak C-H⋯O and C-H⋯Cl hydrogen bonds into a three-dimensional supra-molecular network.

2-(4-Hy­droxy­phen­yl)-1H-benzimidazol-3-ium chloride monohydrate

PubMed Central

González-Padilla, Jazmin E.; Rosales-Hernández, Martha Cecila; Padilla-Martínez, Itzia I.; García-Báez, Efren V.; Rojas-Lima, Susana

2013-01-01

The title mol­ecular salt, C13H11N2O+·Cl−·H2O, crystallizes as a monohydrate. In the cation, the phenol and benzimidazole rings are almost coplanar, making a dihedral angle of 3.18 (4)°. The chloride anion and benzimidazole cation are linked by two N+—H⋯Cl− hydrogen bonds, forming chains propagating along [010]. These chains are linked through O—H⋯Cl hydrogen bonds involving the water mol­ecule and the chloride anion, which form a diamond core, giving rise to the formation of two-dimensional networks lying parallel to (10-2). Two π–π inter­actions involving the imidazolium ring with the benzene and phenol rings [centroid–centroid distances = 3.859 (3) and 3.602 (3) Å, respectively], contribute to this second dimension. A strong O—H⋯O hydrogen bond involving the water mol­ecule and the phenol substituent on the benzimidazole unit links the networks, forming a three-dimensional structure. PMID:24427105

Structural determination of the acidic exopolysaccharide produced by a Pseudomonas sp. strain 1.15.

PubMed

Cescutti, P; Toffanin, R; Pollesello, P; Sutherland, I W

1999-01-31

Pseudomonas strain 1.15 was isolated from a freshwater biofilm and shown to produce considerable amounts of an acidic polysaccharide which was investigated by methylation analysis, NMR spectroscopy and ionspray mass spectrometry (ISMS). The polysaccharide was depolymerised by a bacteriophage-associated endoglucosidase and by autohydrolysis, and the resulting oligosaccharides were investigated by NMR spectroscopy and mass spectrometry. The resulting data showed that the parent repeating unit of the 1.15 exopolysaccharide (EPS) is a branched hexasaccharide. The main chain is constituted of the trisaccharide -->4)-alpha-L-Fucp-(1-->4)-alpha-L-Fucp-(1-->3)-beta-D-Glcp- (1--> and the side chain alpha-D-Galp-(1-->4)-beta-D-GlcAp-(1-->3)-alpha-D-Galp-(1-->is linked to O-3 of the first Fuc residue. The terminal non-reducing Gal carries a 1-carboxyethylidene acetal in the R configuration at the positions 4 and 6. Of the four different O-acetyl groups present in non-stoichiometric amounts, two were established to be on O-2 of the 3-linked Gal and on O-2 of the 4-linked Fuc.

The solubilization of bone and dentin collagens by pepsin. Effect of cross-linkages and non-collagen components.

PubMed

Carmichael, D J; Dodd, C M; Veis, A

1977-03-28

Bone and dentin collagen are less susceptible to solubilization by pepsin digestion then is skin collagen. Digestion at 4 degrees C for 72 h solubilized only 35.3% of bovine cortical bone and 5.6% of bovine dentin compared with nearly 100% dissolution of bovine skin. Sodium dodecyl sulfate-acrylamide gel electrophoresis and molecular sieve chromatography showed that, for bone and dentin, intact alpha chains and cross-linked aggregates of beta, gamma and higher weight remained intact after pepsin solubilization but lower molecular weight fragments also were prevalent indicating chain scission in helical regions. Electron microscopic examination of segment long spacing precipitates of the soluble collagens confirmed the presence of solubilized polymerized collagen. The principal reducible cross-link in both bone and dentin was the precursor of dihydroxylsinonorleucine and this cross-link was also present in the solubilized collagens. Small amounts of non-collagenous proteins and glycosaminoglycans of different compositions in dentin and bone resisted extraction before pepsin digestion. However, the differences in solubilization of the collagens have been related to differences in cross-linkage placement.

Genetics Home Reference: short/branched chain acyl-CoA dehydrogenase deficiency

MedlinePlus

... PDF) Orphanet: 2-methylbutyryl-CoA dehydrogenase deficiency Screening, Technology, and Research in Genetics Patient Support and Advocacy Resources (2 links) Children Living with Inherited Metabolic Diseases (CLIMB) Organic Acidemia ...

Genetics Home Reference: 3-hydroxyacyl-CoA dehydrogenase deficiency

MedlinePlus

... short chain 3-hydroxylacyl-CoA dehydrogenase deficiency Screening, Technology and Research in Genetics (STAR-G) Patient Support and Advocacy Resources (3 links) Children Living with Inherited Metabolic Diseases (CLIMB) FOD (Fatty ...

30 CFR 77.1906 - Hoists; daily inspection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... wheels, etc.), connections, links and chains, and other facilities. (b) Prior to each working shift, and... shall be run by the hoist operator through one complete cycle of operation before any person is...

Exploring the evolutionary mechanism of complex supply chain systems using evolving hypergraphs

NASA Astrophysics Data System (ADS)

Suo, Qi; Guo, Jin-Li; Sun, Shiwei; Liu, Han

2018-01-01

A new evolutionary model is proposed to describe the characteristics and evolution pattern of supply chain systems using evolving hypergraphs, in which nodes represent enterprise entities while hyperedges represent the relationships among diverse trades. The nodes arrive at the system in accordance with a Poisson process, with the evolving process incorporating the addition of new nodes, linking of old nodes, and rewiring of links. Grounded in the Poisson process theory and continuum theory, the stationary average hyperdegree distribution is shown to follow a shifted power law (SPL), and the theoretical predictions are consistent with the results of numerical simulations. Testing the impact of parameters on the model yields a positive correlation between hyperdegree and degree. The model also uncovers macro characteristics of the relationships among enterprises due to the microscopic interactions among individuals.

Li0.5Al0.5Mg2(MoO4)3

PubMed Central

Ennajeh, Ines; Zid, Mohamed Faouzi; Driss, Ahmed

2013-01-01

The title compound, lithium/aluminium dimagnesium tetra­kis­[orthomolybdate(VI)], was prepared by a solid-state reaction route. The crystal structure is built up from MgO6 octa­hedra and MoO4 tetra­hedra sharing corners and edges, forming two types of chains running along [100]. These chains are linked into layers parallel to (010) and finally linked by MoO4 tetra­hedra into a three-dimensional framework structure with channels parallel to [001] in which lithium and aluminium cations equally occupy the same position within a distorted trigonal–bipyramidal coordination environment. The title structure is isotypic with LiMgIn(MoO4)3, with the In site becoming an Mg site and the fully occupied Li site a statistically occupied Li/Al site in the title structure. PMID:24426975

Crystal structure of N-{[3-bromo-1-(phenyl-sulfon-yl)-1H-indol-2-yl]meth-yl}benzene-sulfonamide.

PubMed

Umadevi, M; Raju, P; Yamuna, R; Mohanakrishnan, A K; Chakkaravarthi, G

2015-10-01

In the title compound, C21H17BrN2O4S2, the indole ring system subtends dihedral angles of 85.96 (13) and 9.62 (16)° with the planes of the N- and C-bonded benzene rings, respectively. The dihedral angles between the benzene rings is 88.05 (17)°. The mol-ecular conformation is stabilized by intra-molecular N-H⋯O and C-H⋯O hydrogen bonds and an aromatic π-π stacking [centroid-to-centroid distance = 3.503 (2) Å] inter-action. In the crystal, short Br⋯O [2.9888 (18) Å] contacts link the mol-ecules into [010] chains. The chains are cross-linked by weak C-H⋯π inter-actions, forming a three-dimensional network.

Carbyne from first principles: chain of C atoms, a nanorod or a nanorope.

PubMed

Liu, Mingjie; Artyukhov, Vasilii I; Lee, Hoonkyung; Xu, Fangbo; Yakobson, Boris I

2013-11-26

We report an extensive study of the properties of carbyne using first-principles calculations. We investigate carbyne's mechanical response to tension, bending, and torsion deformations. Under tension, carbyne is about twice as stiff as the stiffest known materials and has an unrivaled specific strength of up to 7.5 × 10(7) N·m/kg, requiring a force of ∼10 nN to break a single atomic chain. Carbyne has a fairly large room-temperature persistence length of about 14 nm. Surprisingly, the torsional stiffness of carbyne can be zero but can be "switched on" by appropriate functional groups at the ends. Further, under appropriate termination, carbyne can be switched into a magnetic semiconductor state by mechanical twisting. We reconstruct the equivalent continuum elasticity representation, providing the full set of elastic moduli for carbyne, showing its extreme mechanical performance (e.g., a nominal Young's modulus of 32.7 TPa with an effective mechanical thickness of 0.772 Å). We also find an interesting coupling between strain and band gap of carbyne, which is strongly increased under tension, from 2.6 to 4.7 eV under a 10% strain. Finally, we study the performance of carbyne as a nanoscale electrical cable and estimate its chemical stability against self-aggregation, finding an activation barrier of 0.6 eV for the carbyne-carbyne cross-linking reaction and an equilibrium cross-link density for two parallel carbyne chains of 1 cross-link per 17 C atoms (2.2 nm).

K11- and K48-Linked Ubiquitin Chains Interact with p97 during Endoplasmic Reticulum-Associated Degradation

PubMed Central

Locke, Matthew; Toth, Julia I.; Petroski, Matthew D.

2014-01-01

The AAA+ ATPase p97 has a critical function in the cytoplasmic degradation of proteins misfolded in the endoplasmic reticulum through a mechanism known as ER-associated degradation (ERAD). During this process, p97 binds polyubiquitinated ERAD substrates and couples ATP hydrolysis to their dislocation from the ER as a prerequisite to destruction by the proteasome. The ubiquitin signals important for this process are not fully understood. Here we report that p97 interacts with lysine 11 (K11) and K48-linked ubiquitin polymers, but not those containing K63 linkages. Disruption of p97 through siRNA-mediated depletion, dominant negative over-expression, or chemical inhibition results in the accumulation of K11 and K48 ubiquitin chains predominantly at the ER membrane, and is associated with ER stress induction. We show that a catalytically inactive deubiquitinating enzyme and p97 cofactor YOD1 enhances the accumulation of K11- and K48-linked polyubiquitin in the cytoplasm, at the ER membrane, and bound to p97. In addition to general effects on p97-associated ubiquitin polymers, the ERAD substrate CD3δ is modified with both K11- and K48-ubiquitin chains prior to p97-dependent dislocation. Collectively, our data are consistent with a major role for p97 in the recognition of K11 and K48 polyubiquitinated proteins prior to their degradation by the proteasome. PMID:24417208

Activation of Duck RIG-I by TRIM25 Is Independent of Anchored Ubiquitin

PubMed Central

Miranzo-Navarro, Domingo; Magor, Katharine E.

2014-01-01

Retinoic acid inducible gene I (RIG-I) is a viral RNA sensor crucial in defense against several viruses including measles, influenza A and hepatitis C. RIG-I activates type-I interferon signalling through the adaptor for mitochondrial antiviral signaling (MAVS). The E3 ubiquitin ligase, tripartite motif containing protein 25 (TRIM25), activates human RIG-I through generation of anchored K63-linked polyubiquitin chains attached to lysine 172, or alternatively, through the generation of unanchored K63-linked polyubiquitin chains that interact non-covalently with RIG-I CARD domains. Previously, we identified RIG-I of ducks, of interest because ducks are the host and natural reservoir of influenza viruses, and showed it initiates innate immune signaling leading to production of interferon-beta (IFN-β). We noted that K172 is not conserved in RIG-I of ducks and other avian species, or mouse. Because K172 is important for both mechanisms of activation of human RIG-I, we investigated whether duck RIG-I was activated by TRIM25, and if other residues were the sites for attachment of ubiquitin. Here we show duck RIG-I CARD domains are ubiquitinated for activation, and ubiquitination depends on interaction with TRIM25, as a splice variant that cannot interact with TRIM25 is not ubiquitinated, and cannot be activated. We expressed GST-fusion proteins of duck CARD domains and characterized TRIM25 modifications of CARD domains by mass spectrometry. We identified two sites that are ubiquitinated in duck CARD domains, K167 and K193, and detected K63 linked polyubiquitin chains. Site directed mutagenesis of each site alone, does not alter the ubiquitination profile of the duck CARD domains. However, mutation of both sites resulted in loss of all attached ubiquitin and polyubiquitin chains. Remarkably, the double mutant duck RIG-I CARD still interacts with TRIM25, and can still be activated. Our results demonstrate that anchored ubiquitin chains are not necessary for TRIM25 activation of duck RIG-I. PMID:24466302

Rapid self-healing hydrogels

PubMed Central

Phadke, Ameya; Zhang, Chao; Arman, Bedri; Hsu, Cheng-Chih; Mashelkar, Raghunath A.; Lele, Ashish K.; Tauber, Michael J.; Arya, Gaurav; Varghese, Shyni

2012-01-01

Synthetic materials that are capable of autonomous healing upon damage are being developed at a rapid pace because of their many potential applications. Despite these advancements, achieving self-healing in permanently cross-linked hydrogels has remained elusive because of the presence of water and irreversible cross-links. Here, we demonstrate that permanently cross-linked hydrogels can be engineered to exhibit self-healing in an aqueous environment. We achieve this feature by arming the hydrogel network with flexible-pendant side chains carrying an optimal balance of hydrophilic and hydrophobic moieties that allows the side chains to mediate hydrogen bonds across the hydrogel interfaces with minimal steric hindrance and hydrophobic collapse. The self-healing reported here is rapid, occurring within seconds of the insertion of a crack into the hydrogel or juxtaposition of two separate hydrogel pieces. The healing is reversible and can be switched on and off via changes in pH, allowing external control over the healing process. Moreover, the hydrogels can sustain multiple cycles of healing and separation without compromising their mechanical properties and healing kinetics. Beyond revealing how secondary interactions could be harnessed to introduce new functions to chemically cross-linked polymeric systems, we also demonstrate various potential applications of such easy-to-synthesize, smart, self-healing hydrogels. PMID:22392977

Towards an understanding of the link between environmental emissions and human body burdens of PCBs using CoZMoMAN.

PubMed

Breivik, Knut; Czub, Gertje; McLachlan, Michael S; Wania, Frank

2010-01-01

Different factors affect how organic contaminants released into the environment over time distribute and accumulate, enter various food-chains, and potentially cause toxic effects in wildlife and humans. A sound chemical risk assessment thus requires the determination of the quantitative relationship between emissions and human exposure. This study aimed to assess the extent of the quantitative and mechanistic understanding of the link between environmental emissions and human body burdens for polychlorinated biphenyls (PCBs) in the western part of the Baltic Sea drainage basin and to identify any remaining knowledge gaps. An integrated, non-steady state model calculating human body burden from environmental emissions (CoZMoMAN) was created by linking the multi-compartment environmental fate model CoZMo-POP 2 with the human food chain bioaccumulation model ACC-HUMAN. CoZMoMAN predicted concentrations of seven PCB congeners in 11 key model compartments to typically within a factor of 2 to 4 of measured values, although larger discrepancies are noted for soils and humans. We conclude that whereas the most important processes which link emissions of PCBs to human body burdens are quite well understood in this region, some critical knowledge gaps related to the time trend of historical emissions remain to be addressed.

Structure-induced switching of interpolymer adhesion at a solid-polymer melt interface.

PubMed

Jiang, Naisheng; Sen, Mani; Zeng, Wenduo; Chen, Zhizhao; Cheung, Justin M; Morimitsu, Yuma; Endoh, Maya K; Koga, Tadanori; Fukuto, Masafumi; Yuan, Guangcui; Satija, Sushil K; Carrillo, Jan-Michael Y; Sumpter, Bobby G

2018-02-14

Here we report a link between the interfacial structure and adhesive property of homopolymer chains physically adsorbed (i.e., via physisorption) onto solids. Polyethylene oxide (PEO) was used as a model and two different chain conformations of the adsorbed polymer were created on silicon substrates via the well-established Guiselin's approach: "flattened chains" which lie flat on the solid and are densely packed, and "loosely adsorbed polymer chains" which form bridges jointing up nearby empty sites on the solid surface and cover the flattened chains. We investigated the adhesion properties of the two different adsorbed chains using a custom-built adhesion testing device. Bilayers of a thick PEO overlayer on top of the flattened chains or loosely adsorbed chains were subjected to the adhesion test. The results revealed that the flattened chains do not show any adhesion even with the chemically identical free polymer on top, while the loosely adsorbed chains exhibit adhesion. Neutron reflectivity experiments corroborated that the difference in the interfacial adhesion is not attributed to the interfacial brodening at the free polymer-adsorbed polymer interface. Instead, coarse-grained molecular dynamics simulation results suggest that the tail parts of the loosely adsorbed chains act as "connector molecules", bridging the free chains and substrate surface and improving the interfacial adhesion. These findings not only shed light on the structure-property relationship at the interface, but also provide a novel approach for developing sticking/anti-sticking technologies through precise control of the interfacial polymer nanostructures.

Subunit composition and structure of subcomponent C1q of the first component of human complement.

PubMed

Reid, K B; Porter, R R

1976-04-01

1. Unreduced human subcomponent C1q was shown by electrophoresis on polyacrylamide gels run in the presence of sodium dodecyl sulphate to be composed of two types of non-covalently linked subunits of apparent mol.wts. 69 000 and 54 000. The ratio of the two subunits was markedly affected by the ionic strength of the applied sample. At a low ionic strength of applied sample, which gave the optimum value for the 54 000-apparent mol.wt. subunit, a ratio of 1.99:1.00 was obtained for the ratio of the 69 000-apparent mol.wt. subunit to the 5400-apparent-mol.wt. subunit. The amount of the 54 000-apparent-mol.wt. subunit detected in the expected position on the gel was found to be inversely proportional to increases in the ionic strength of the applled sample. 2. Human subcomponent C1q on reduction and alkylation, or oxidation, yields equimolar amounts of three chains designated A, B and C [Reid et al. (1972) Biochem. J. 130, 749-763]. The results obtained by Yonemasu & Stroud [(1972) Immunochemistry 9, 545-554], which showed that the 69 000-apparent-mol.wt. subunit was a disulphide-linked dimer of the A and B chains and that the 54 000-apparent-mol.wt. subunit was a disulphide-linked dimer of the C chain, were confirmed. 3. Gel filtration on Sephadex G-200 in 6.0M-guanidinium chloride showed that both types of unreduced subunit were eluted together as a single symmetrical peak of apparent mol.wt. 49 000-50 000 when globular proteins were used as markers. The molecular weights of the oxidized or reduced A, B and C chains have been shown previously to be very similar all being in the range 23 000-24 000 [Reid et al. (1972) Biochem. J. 130, 749-763; Reid (1974) Biochem. J. 141, 189-203]. 4. It is proposed that subcomponent C1q (mol.wt. 410000) is composed of nine non-covalently linked subunits, i.e. six A-B dimers and three C-C dimers. 5. A structure for subcomponent C1q is proposed and is based on the assumption that the collagen-like regions of 78 residues in each of the A, B and C chains are combined to form a triple-helical structure of the same type as is found in collagens.

Crystal structure and charge transport properties of poly(arylene-ethynylene) derivatives: A DFT approach

NASA Astrophysics Data System (ADS)

Garzón, Andrés; Granadino-Roldán, José M.; García, Gregorio; Moral, Mónica; Fernández-Gómez, Manuel

2013-04-01

In the present study, a series of crystalline poly(arylene-ethynylene) copolymers containing phenylethynylene and 2,5-dialkoxy-phenylethynylene units together with 1,3,4-thiadiazole rings has been modeled by means of periodic calculations. Optimized three-dimensional polymeric structures show interchain distances that are consistent with the experimental values reported for a related polymer. It has also been observed that the presence of pendant alkoxy chains brings on both a further flattening and a separation of the coplanar chains. This fact is linked to a decrease of the interchain cofacial distance. The electron transport character of the polymer crystal structures was assessed through Marcus theory. Electronic coupling between neighboring polymer chains is most influenced by the presence of alkoxy chains giving rise to an expectable enhancement of the electron hopping mobility.

35. DETAIL VIEW OF GUNITEENCASED CONCRETE PILINGS AT BENT 6, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

35. DETAIL VIEW OF GUNITE-ENCASED CONCRETE PILINGS AT BENT 6, LOOKING SOUTHWEST (CAMERA AGAINST CHAIN-LINK FENCE) - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alcaraz, Francisco Castilho; Ibanez Berganza, Miguel; Sierra, German

In a quantum critical chain, the scaling regime of the energy and momentum of the ground state and low-lying excitations are described by conformal field theory (CFT). The same holds true for the von Neumann and Renyi entropies of the ground state, which display a universal logarithmic behavior depending on the central charge. In this Letter we generalize this result to those excited states of the chain that correspond to primary fields in CFT. It is shown that the nth Renyi entropy is related to a 2n-point correlator of primary fields. We verify this statement for the critical XX andmore » XXZ chains. This result uncovers a new link between quantum information theory and CFT.« less

Shear and elongational rheology of photo-oxidative degraded HDPE and LLDPE

NASA Astrophysics Data System (ADS)

Wagner, Manfred Hermann; Zheng, Wang; Wang, Peng; Talamante, Sebastián Ramos; Narimissa, Esmaeil

2017-05-01

The effect of photo-oxidative degradation of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE) was investigated by linear and non-linear rheological measurements. The linear-viscoelastic rheological measurements were performed at different temperatures, while the elongational viscosity was measured at 170°C and at different strain rates. The rheological data are indicative of structural changes caused by photo-oxidative degradation including formation of long-chain branches (LCB), cross-linking, and chain scission, and they revealed a cyclic and continuing competition between chain scission and LCB/gel formation. These findings are supported by additional FTIR measurements and direct measurements of the gel content of the degraded samples.

2-Oxoamide inhibitors of cytosolic group IVA phospholipase A2 with reduced lipophilicity.

PubMed

Antonopoulou, Georgia; Magrioti, Victoria; Kokotou, Maroula G; Nikolaou, Aikaterini; Barbayianni, Efrosini; Mouchlis, Varnavas D; Dennis, Edward A; Kokotos, George

2016-10-01

Cytosolic GIVA phospholipase A2 (GIVA cPLA2) initiates the eicosanoid pathway of inflammation and thus inhibitors of this enzyme constitute novel potential agents for the treatment of inflammatory diseases. Traditionally, GIVA cPLA2 inhibitors have suffered systemically from high lipophilicity. We have developed a variety of long chain 2-oxoamides as inhibitors of GIVA PLA2. Among them, AX048 was found to produce a potent analgesic effect. We have now reduced the lipophilicity of AX048 by replacing the long aliphatic chain with a chain containing an ether linked aromatic ring with in vitro inhibitory activities similar to AX048. Copyright © 2016 Elsevier Ltd. All rights reserved.

The use of heteroduplex analysis of polymerase chain reaction products to support the possible transmission of Legionella pneumophila from a malfunctioning automobile air conditioner.

PubMed

Pinar, Ahmet; Ramirez, Julio A; Schindler, Laura L; Miller, Richard D; Summersgill, James T

2002-03-01

Air conditioner condensates have not been previously associated with cases of Legionnaires' disease. We report the possible transmission of Legionella pneumophila serogroup 1 from a malfunctioning automobile air conditioning system's leaking water onto the floorboard of a car driven for a long distance by the patient. Heteroduplex analysis of polymerase chain reaction products was used to help establish an epidemiologic link between the water specimen and the patient.

The Balloon Effect and Mexican Homeland Security: What it Means to be the Weakest Link in the Americas’ Security Chain

DTIC Science & Technology

2011-12-01

in the Social Sciences (George & Bennett, 2005), the main challenges of this thesis are: 9  To test the hypothesis of whether the implications of...Americas´ security chain;  To test whether the new concept of balloon-effect counter-pressure coming from the Mexican strategy is influencing latent...balloon effects against U.S. homeland security;  To test whether those balloon effects created by the Mexican strategy inside Mexico are a

2,2',5,5'-Tetra-methyl-1,1'-(hexane-1,6-di-yl)di-1H-pyrrole.

PubMed

Santos, Ana C; Ramos Silva, Manuela; Monsanto, Paula V; Matos Beja, Ana; Sobral, Abilio J F N

2009-06-17

The mol-ecule of the title compound, C(18)H(28)N(2), composed of two 2,5-dimethyl-pyrrole groups linked by a hexane chain, lies across a crystallographic inversion centre. The mean plane of the pyrrole ring is almost perpendicular to the mean plane of the central chain, making a dihedral angle of 89.09 (8)°. The crystal structure is stabilized by inter-molecular C-H⋯π inter-actions.

catena-Poly[[[4,6-bis­(2-pyrid­yl)-1,3,5-triazin-2-olato]copper(II)]-μ-chlorido

PubMed Central

Cao, Man-Li

2011-01-01

The title compound, [Cu(C13H8N5O)Cl]n, has a chain structure parallel to [100] with Cu2+ cations in a trigonal–bipyramidal coordination environment. The ligand adopts a tridentate tripyridyl coordination mode and a chloride ion acts as a bridge. The chains are linked via weak C—H⋯O and C—H⋯Cl hydrogen bonds into a three-dimensional supra­molecular network. PMID:21754632

Respiratory chain supercomplexes associate with the cysteine desulfurase complex of the iron–sulfur cluster assembly machinery

PubMed Central

Böttinger, Lena; Mårtensson, Christoph U.; Song, Jiyao; Zufall, Nicole; Wiedemann, Nils; Becker, Thomas

2018-01-01

Mitochondria are the powerhouses of eukaryotic cells. The activity of the respiratory chain complexes generates a proton gradient across the inner membrane, which is used by the F1FO-ATP synthase to produce ATP for cellular metabolism. In baker’s yeast, Saccharomyces cerevisiae, the cytochrome bc1 complex (complex III) and cytochrome c oxidase (complex IV) associate in respiratory chain supercomplexes. Iron–sulfur clusters (ISC) form reactive centers of respiratory chain complexes. The assembly of ISC occurs in the mitochondrial matrix and is essential for cell viability. The cysteine desulfurase Nfs1 provides sulfur for ISC assembly and forms with partner proteins the ISC-biogenesis desulfurase complex (ISD complex). Here, we report an unexpected interaction of the active ISD complex with the cytochrome bc1 complex and cytochrome c oxidase. The individual deletion of complex III or complex IV blocks the association of the ISD complex with respiratory chain components. We conclude that the ISD complex binds selectively to respiratory chain supercomplexes. We propose that this molecular link contributes to coordination of iron–sulfur cluster formation with respiratory activity. PMID:29386296

Isomeric Detergent Comparison for Membrane Protein Stability: Importance of Inter-Alkyl-Chain Distance and Alkyl Chain Length

PubMed Central

Cho, Kyung Ho; Hariharan, Parameswaran; Mortensen, Jonas S.; Du, Yang; Nielsen, Anne K.; Byrne, Bernadette; Kobilka, Brian K.; Loland, Claus J.; Guan, Lan

2017-01-01

Membrane proteins encapsulated by detergent micelles are widely used for structural study. Because of their amphipathic property, detergents have the ability to maintain protein solubility and stability in an aqueous medium. However, conventional detergents have serious limitations in their scope and utility, particularly for eukaryotic membrane proteins and membrane protein complexes. Thus, a number of new agents have been devised; some have made significant contributions to membrane protein structural studies. However, few detergent design principles are available. In this study, we prepared meta and ortho isomers of the previously reported para-substituted xylene-linked maltoside amphiphiles (XMAs), along with alkyl chain-length variation. The isomeric XMAs were assessed with three membrane proteins, and the meta isomer with a C12 alkyl chain was most effective at maintaining solubility/stability of the membrane proteins. We propose that interplay between the hydrophile–lipophile balance (HLB) and alkyl chain length is of central importance for high detergent efficacy. In addition, differences in inter-alkyl-chain distance between the isomers influence the ability of the detergents to stabilise membrane proteins. PMID:27981750

Medium-chain fatty acids as ligands for orphan G protein-coupled receptor GPR84.

PubMed

Wang, Jinghong; Wu, Xiaosu; Simonavicius, Nicole; Tian, Hui; Ling, Lei

2006-11-10

Free fatty acids (FFAs) play important physiological roles in many tissues as an energy source and as signaling molecules in various cellular processes. Elevated levels of circulating FFAs are associated with obesity, dyslipidemia, and diabetes. Here we show that GPR84, a previously orphan G protein-coupled receptor, functions as a receptor for medium-chain FFAs with carbon chain lengths of 9-14. Medium-chain FFAs elicit calcium mobilization, inhibit 3',5'-cyclic AMP production, and stimulate [35S]guanosine 5'-O-(3-thiotriphosphate) binding in a GPR84-dependent manner. The activation of GPR84 by medium-chain FFAs couples primarily to a pertussis toxin-sensitive G(i/o) pathway. In addition, we show that GPR84 is selectively expressed in leukocytes and markedly induced in monocytes/macrophages upon activation by lipopolysaccharide. Furthermore, we demonstrate that medium-chain FFAs amplify lipopolysaccharide-stimulated production of the proinflammatory cytokine interleukin-12 p40 through GPR84. Our results indicate a role for GPR84 in directly linking fatty acid metabolism to immunological regulation.

The Crystal Structure and Conformations of an Unbranched Mixed Tri-Ubiquitin Chain Containing K48 and K63 Linkages.

PubMed

Padala, Prasanth; Soudah, Nadine; Giladi, Moshe; Haitin, Yoni; Isupov, Michail N; Wiener, Reuven

2017-12-08

The ability of ubiquitin to function in a wide range of cellular processes is ascribed to its capacity to cause a diverse spectrum of modifications. While a target protein can be modified with monoubiquitin, it can also be modified with ubiquitin chains. The latter include seven types of homotypic chains as well as mixed ubiquitin chains. In a mixed chain, not all the isopeptide bonds are restricted to a specific lysine of ubiquitin, resulting in a chain possessing more than one type of linkage. While structural characterization of homotypic chains has been well elucidated, less is known about mixed chains. Here we present the crystal structure of a mixed tri-ubiquitin chain at 3.1-Å resolution. In the structure, the proximal ubiquitin is connected to the middle ubiquitin via K48 and these two ubiquitins adopt a compact structure as observed in K48 di-ubiquitin. The middle ubiquitin links to the distal ubiquitin via its K63 and these ubiquitins adopt two conformations, suggesting a flexible structure. Using small-angle X-ray scattering, we unexpectedly found differences between the conformational ensembles of the above tri-ubiquitin chains and chains possessing the same linkages but in the reverse order. In addition, cleavage of the K48 linkage by DUB is faster if this linkage is at the distal end. Taken together, our results suggest that in mixed chains, not only the type of the linkages but also their sequence determine the structural and functional properties of the chain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial Discrimination Reversal and Incremental Repeated Acquisition in Adolescent and Adult BALB/c Mice

PubMed Central

Shen, Andrew Nathanael; Pope, Derek A.; Hutsell, Blake A.; Newland, M. Christopher

2015-01-01

Adolescence is characterized by neural and behavior development that includes increases in novel experiences and impulsive choice. Experimental rodent models can characterize behavior phenotypes that typify adolescence. The present experiment was designed to characterize differences between adolescent (post-natal day (PND) 34 - 60) and adult (PND 70 - 96) BALB/c mice using a response-initiated spatial discrimination reversal (SDR) and incremental repeated acquisition of response chains (IRA) procedures. During SDR, adolescents omitted more trials and were slower to initiate trials than adults, but the age groups did not differ on accuracy and perseveration measures. During IRA, adolescents displayed poorer overall performance (measured by progress quotient), lower accuracy at individual chain links, and completed fewer long response chains (>3 links) than adults. In both procedures (SDR and IRA), the poorer performance of adolescents appeared to be related to the use of a response device that was spatially removed from reinforcer delivery. These results indicate that SDR and IRA performance can be established during the brief rodent adolescent period but that these two age groups’ performances differ. We hypothesize that adolescent behavior is more sensitive than adult behavior to the spatiotemporal distance between response device and location of reinforcer delivery. PMID:26051193

Measures of International Manufacturing and Trade of Clean Energy Technologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Engel-Cox, Jill; Sandor, Debbie; Keyser, David

The technologies that produce clean energy, such as solar photovoltaic panels and lithium ion batteries for electric vehicles, are globally manufactured and traded. As demand and deployment of these technologies grows exponentially, the innovation to reach significant economies of scale and drive down energy production costs becomes less in the technology and more in the manufacturing of the technology. Manufacturing innovations and other manufacturing decisions can reduce costs of labor, materials, equipment, operating costs, and transportation, across all the links in the supply chain. To better understand the manufacturing aspect of the clean energy economy, we have developed key metricsmore » for systematically measuring and benchmarking international manufacturing of clean energy technologies. The metrics are: trade, market size, manufacturing value-added, and manufacturing capacity and production. These metrics were applied to twelve global economies and four representative technologies: wind turbine components, crystalline silicon solar photovoltaic modules, vehicle lithium ion battery cells, and light emitting diode packages for efficient lighting and other consumer products. The results indicated that clean energy technologies are being developed via complex, dynamic, and global supply chains, with individual economies benefiting from different technologies and links in the supply chain, through both domestic manufacturing and global trade.« less

Crystal structure of poly[[μ-4-(hy-droxy-meth-yl)pyridine-κ(2) N:O][4-(hy-droxy-meth-yl)pyridine-κN](μ-thio-cyanato-κ(2) N:S)(thio-cyanato-κN)cadmium].

PubMed

Werner, Julia; Jess, Inke; Näther, Christian

2015-06-01

The crystal structure of the title compound, [Cd(NCS)2(C6H7NO)2] n is made up of Cd(2+) cations that are coordinated by three thio-cyanate ligands and three 4-(hy-droxy-meth-yl)pyridine ligands within distorted N4OS octa-hedra. The asymmetric unit consists of one Cd(2+) cation, two thio-cyanate anions and two 4-(hy-droxy-meth-yl)pyridine ligands in general positions. Two Cd(2+) cations are linked by two μ-1,3 N- and S-bonding thio-ycanate anions into dimers which are further linked into branched chains along [100] by two μ-1,6 N- and O-bonding 4-(hy-droxy-meth-yl)pyridine ligands. One additional N-bonded 4-(hy-droxy-meth-yl)pyridine ligand and one additional N-bonded thio-cyanate anion are only terminally bonded to the metal cation. Inter-chain O-H⋯S hydrogen bonds between the hy-droxy H atoms and one of the thio-cyanate S atoms connect the chains into a three-dimensional network.

Interplay of signal recognition particle and trigger factor at L23 near the nascent chain exit site on the Escherichia coli ribosome

PubMed Central

Ullers, Ronald S.; Houben, Edith N.G.; Raine, Amanda; ten Hagen-Jongman, Corinne M.; Ehrenberg, Måns; Brunner, Joseph; Oudega, Bauke; Harms, Nellie; Luirink, Joen

2003-01-01

As newly synthesized polypeptides emerge from the ribosome, they interact with chaperones and targeting factors that assist in folding and targeting to the proper location in the cell. In Escherichia coli, the chaperone trigger factor (TF) binds to nascent polypeptides early in biosynthesis facilitated by its affinity for the ribosomal proteins L23 and L29 that are situated around the nascent chain exit site on the ribosome. The targeting factor signal recognition particle (SRP) interacts specifically with the signal anchor (SA) sequence in nascent inner membrane proteins (IMPs). Here, we have used photocross-linking to map interactions of the SA sequence in a short, in vitro–synthesized, nascent IMP. Both TF and SRP were found to interact with the SA with partially overlapping binding specificity. In addition, extensive contacts with L23 and L29 were detected. Both purified TF and SRP could be cross-linked to L23 on nontranslating ribosomes with a competitive advantage for SRP. The results suggest a role for L23 in the targeting of IMPs as an attachment site for TF and SRP that is close to the emerging nascent chain. PMID:12756233

The Arabidopsis COBRA Protein Facilitates Cellulose Crystallization at the Plasma Membrane*

PubMed Central

Sorek, Nadav; Sorek, Hagit; Kijac, Aleksandra; Szemenyei, Heidi J.; Bauer, Stefan; Hématy, Kian; Wemmer, David E.; Somerville, Chris R.

2014-01-01

Mutations in the Arabidopsis COBRA gene lead to defects in cellulose synthesis but the function of COBRA is unknown. Here we present evidence that COBRA localizes to discrete particles in the plasma membrane and is sensitive to inhibitors of cellulose synthesis, suggesting that COBRA and the cellulose synthase complex reside in close proximity on the plasma membrane. Live-cell imaging of cellulose synthesis indicated that, once initiated, cellulose synthesis appeared to proceed normally in the cobra mutant. Using isothermal calorimetry, COBRA was found to bind individual β1–4-linked glucan chains with a KD of 3.2 μm. Competition assays suggests that COBRA binds individual β1–4-linked glucan chains with higher affinity than crystalline cellulose. Solid-state nuclear magnetic resonance studies of the cell wall of the cobra mutant also indicated that, in addition to decreases in cellulose amount, the properties of the cellulose fibrils and other cell wall polymers differed from wild type by being less crystalline and having an increased number of reducing ends. We interpret the available evidence as suggesting that COBRA facilitates cellulose crystallization from the emerging β1–4-glucan chains by acting as a “polysaccharide chaperone.” PMID:25331944

The role of the carbohydrate chains in complement (C3) fixation by solid-phase-bound human IgA.

PubMed Central

Nikolova, E B; Tomana, M; Russell, M W

1994-01-01

In contrast to antigen-antibody complexes containing native human IgA, solid-phase-deposited IgA activates the alternative complement pathway and binds C3b. To investigate the role of carbohydrate chains in this, various human IgA preparations were treated with neuraminidase alone or together with N-glycanase or O-glycanase, or with mixed glycosidases from the oral bacterium, Streptococcus mitis. Depletion of oligosaccharides was determined by carbohydrate analysis. Removal of sialic acid and N-linked glycan chains greatly increased the C3b-fixing properties of normal serum IgA1 and IgA2. Myeloma IgA1 and IgA2 proteins and secretory IgA had higher C3b-binding activity than normal serum IgA, and this was further increased by removal of sialic acid and N-linked glycans. Fc alpha and Fc alpha-SC fragments of myeloma and secretory IgA1, respectively, but not Fab alpha fragments, obtained by cleavage with bacterial IgA1 proteases and also free secretory component, fixed C3b by the alternative pathway. Images Figure 4 PMID:7927504

Data-based control of a multi-step forming process

NASA Astrophysics Data System (ADS)

Schulte, R.; Frey, P.; Hildenbrand, P.; Vogel, M.; Betz, C.; Lechner, M.; Merklein, M.

2017-09-01

The fourth industrial revolution represents a new stage in the organization and management of the entire value chain. However, concerning the field of forming technology, the fourth industrial revolution has only arrived gradually until now. In order to make a valuable contribution to the digital factory the controlling of a multistage forming process was investigated. Within the framework of the investigation, an abstracted and transferable model is used to outline which data have to be collected, how an interface between the different forming machines can be designed tangible and which control tasks must be fulfilled. The goal of this investigation was to control the subsequent process step based on the data recorded in the first step. The investigated process chain links various metal forming processes, which are typical elements of a multi-step forming process. Data recorded in the first step of the process chain is analyzed and processed for an improved process control of the subsequent process. On the basis of the gained scientific knowledge, it is possible to make forming operations more robust and at the same time more flexible, and thus create the fundament for linking various production processes in an efficient way.

Dielectric spectroscopy investigation of proton transfer processes in carboxymethyl alpha-cyclodextrin polymer cross-linked by epichlorohydrin

NASA Astrophysics Data System (ADS)

Papaioannou, Panagoula K.; Karagianni, Chaido S.; Kakali, Glykeria; Charalampopoulos, Vasileios G.

2018-03-01

The carboxymethyl-α-cyclodextrin polymer (cross-linked by epichlorohydrin) is investigated by dielectric spectroscopy over a frequency range of 0.1-100 kHz and the temperature ranges of 137.2-297.6 K (cooling) and 137.2-472 K (heating). Upon cooling to 288.1 K, the ac-conductivity invariance is attributed to slight changes in the topology of the H-bonded chains. From 288.1 to 244.0 K, the ac-conductivity decreases abruptly (following the Arrhenius law with Eα = 0.40 eV), whereas below 244.0 K it presents no important variations. During heating from 137.2 to 302.6 K, no thermal hysteresis is observed. From 302.6 to 364.9 K, the ac-conductivity increases (Eα = 0.71 eV), whereas above 383 K it decreases up to 436.7 K since the dehydration process has been completed and the H-bonded chains can no longer be retained. From 436.7 to 472 K, the ac-conductivity increases again (Eα = 0.76 eV) indicating the formation of "new" H-bonded chains. Curve fitting of various relaxation processes is done by Havriliak-Negami equation at selective temperatures.

Evidence for cross-linking in tomato cutin using HR-MAS NMR spectroscopy.

PubMed

Deshmukh, Ashish P; Simpson, André J; Hatcher, Patrick G

2003-11-01

Cutin is a polyester biopolymer component of plant leaf and fruit cuticles, most often associated with waxes and cuticular polysaccharides, and sometimes with another aliphatic biopolymer called cutan. Insolubility of these cuticular biopolymers has made it difficult to apply traditional analytical techniques for structure determination, because most techniques providing molecular level details require solubility. By using the relatively new technique of one and two-dimensional high-resolution magic angle spinning (HR-MAS) NMR spectroscopy, with added information from solid-state 13C NMR spectroscopy, detailed through-bond connectivities and assignments are made for cutin from Lycopersicon esculentum (tomato) fruit. Based on the data obtained, tomato cutin is found to be predominantly an aliphatic polyester with some olefinic and aromatic moieties, consistent with previous studies that employed various degradative approaches. Aside from esters, there are free primary and secondary alcohol groups, as well as free fatty acids. A significant finding is the presence of alpha-branched fatty acids/esters. Mid-chain hydroxyls appear to be generally unesterified, but esters of mid-chain hydroxyls have been identified. The alpha-branched fatty acids/esters and esters of mid-chain hydroxyls could point towards cross-linking.

Jacalin: a jackfruit (Artocarpus heterophyllus) seed-derived lectin of versatile applications in immunobiological research.

PubMed

Kabir, S

1998-03-15

Jacalin, the major protein from the jackfruit (Artocarpus heterophyllus) seeds, is a tetrameric two-chain lectin (molecular mass 65 kDa) combining a heavy alpha chain of 133 amino acid residues with a light beta chain of 20-21 amino acid residues. It is highly specific for the alpha-O-glycoside of the disaccharide Thomsen-Friedenreich antigen (Gal beta1-3GalNAc), even in its sialylated form. This property has made jacalin suitable for studying various O-linked glycoproteins, particularly human IgA1. Jacalin's uniqueness in being strongly mitogenic for human CD4+ T lymphocytes has made it a useful tool for the evaluation of the immune status of patients infected with human immunodeficiency virus (HIV)-1. The abundance of source material for the production of jacalin, its ease of purification, yield and stability have made it an attractive cost-effective lectin. It has found applications in diverse areas such as the isolation of human plasma glycoproteins (IgA1, C1-inhibitor, hemopexin, alpha2-HSG), the investigation of IgA-nephropathy, the analysis of O-linked glycoproteins and the detection of tumours.

The carbon chain-selective adenylation enzyme TamA: the missing link between fatty acid and pyrrole natural product biosynthesis.

PubMed

Marchetti, Piera M; Kelly, Van; Simpson, Joanna P; Ward, Mairi; Campopiano, Dominic J

2018-04-18

The marine bacterium Pseudoalteromonas tunicata produces the bipyrrole antibiotic tambjamine YP1. This natural product is built from common amino acid and fatty acid building blocks in a biosynthetic pathway that is encoded in the tam operon which contains 19 genes. The exact role that each of these Tam proteins plays in tambjamine biosynthesis is not known. Here, we provide evidence that TamA initiates the synthesis and controls the chain length of the essential tambjamine fatty amine tail. Sequence analysis suggests the unusual TamA is comprised of an N-terminal adenylation (ANL) domain fused to a C-terminal acyl carrier protein (ACP). Mass spectrometry analysis of recombinant TamA revealed the surprising presence of bound C11 and C12 acyl-adenylate intermediates. Acylation of the ACP domain was observed upon attachment of the phosphopantetheine (4'-PP) arm to the ACP. We also show that TamA can transfer fatty acids ranging in chain length from C6-C13 to an isolated ACP domain. Thus TamA bridges the gap between primary and secondary metabolism by linking fatty acid and pyrrole biosynthetic pathways.

An intelligent anti-jamming network system of data link

NASA Astrophysics Data System (ADS)

Fan, Xiangrui; Lin, Jingyong; Liu, Jiarun; Zhou, Chunmei

2017-10-01

Data link is the key information system for the cooperation of weapons, single physical layer anti-jamming technology has been unable to meet its requirements. High dynamic precision-guided weapon nodes like missiles, anti-jamming design of data link system need to have stronger pertinence and effectiveness: the best anti-jamming communication mode can be selected intelligently in combat environment, in real time, guarantee the continuity of communication. We discuss an anti-jamming intelligent networking technology of data link based on interference awareness, put forward a model of intelligent anti-jamming system, and introduces the cognitive node protocol stack model and intelligent anti-jamming method, in order to improve the data chain of intelligent anti-jamming ability.

Profit Analysis Model of Smart Item Implementation in Integrated Supply Chain Process

NASA Astrophysics Data System (ADS)

Tritularsih, Yustina; Rinanto, Andhy; Prasetyo, Hoedi; Nur Rosyidi, Cucuk

2018-03-01

Nowadays all links of the entire supply chain need to integrate their different infrastructures and they have better control of them to drive better profits. This integration should offer the ability for companies in order to have an overall and transparent insight to its supply chain activities. An intelligent supply chain which is mainly supported by Smart Items technology can satisfy the need of those integration. By means of Smart Items, a company can benefit some advantages. Those are cost reduction and value creation. However, currently there is no comprehensive Smart Item infrastructure exists yet so it is difficult to calculate the true benefit information. This paper attempts to recommend a model for estimating the benefits of implementing Smart Items in a company which has an integrated supply chain process. The integrated supply chain means that three echelons (supplier, shipper and retailer) of supply chain are belonged to a company. The proposed model was used to determine the shrinkage value and RFID tag price which can give the maximum benefit of Smart Items implementation. A numerical example is also provided to give a better comprehension on model calculation.

When monoclonal antibodies are not monospecific: Hybridomas frequently express additional functional variable regions

PubMed Central

Bradbury, Andrew R. M.; Trinklein, Nathan D.; Wilkinson, Ian C.; Tandon, Atul K.; Anderson, Stephen; Bladen, Catherine L.; Jones, Brittany; Aldred, Shelley Force; Bestagno, Marco; Burrone, Oscar; Maynard, Jennifer; Ferrara, Fortunato; Görnemann, Janina; Glanville, Jacob; Wolf, Philipp; Frenzel, Andre; Wong, Julin; Koh, Xin Yu; Eng, Hui-Yan; Lane, David; Lefranc, Marie-Paule; Clark, Mike

2018-01-01

ABSTRACT Monoclonal antibodies are commonly assumed to be monospecific, but anecdotal studies have reported genetic diversity in antibody heavy chain and light chain genes found within individual hybridomas. As the prevalence of such diversity has never been explored, we analyzed 185 random hybridomas, in a large multicenter dataset. The hybridomas analyzed were not biased towards those with cloning difficulties or known to have additional chains. Of the hybridomas we evaluated, 126 (68.1%) contained no additional productive chains, while the remaining 59 (31.9%) contained one or more additional productive heavy or light chains. The expression of additional chains degraded properties of the antibodies, including specificity, binding signal and/or signal-to-noise ratio, as determined by enzyme-linked immunosorbent assay and immunohistochemistry. The most abundant mRNA transcripts found in a hybridoma cell line did not necessarily encode the antibody chains providing the correct specificity. Consequently, when cloning antibody genes, functional validation of all possible VH and VL combinations is required to identify those with the highest affinity and lowest cross-reactivity. These findings, reflecting the current state of hybridomas used in research, reiterate the importance of using sequence-defined recombinant antibodies for research or diagnostic use. PMID:29485921

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peterson, Steven K

The U.S. Department of Energy (DOE) has a significant programmatic interest in the safe and secure routing and transportation of Spent Nuclear Fuel (SNF) and High Level Waste (HLW) in the United States, including shipments entering the country from locations outside U.S borders. In any shipment of SNF/HLW, there are multiple chains; a jurisdictional chain as the material moves between jurisdictions (state, federal, tribal, administrative), a physical supply chain (which mode), as well as a custody chain (which stakeholder is in charge/possession) of the materials being transported. Given these interconnected networks, there lies vulnerabilities, whether in lack of communication betweenmore » interested stakeholders or physical vulnerabilities such as interdiction. By identifying key links and nodes as well as administrative weaknesses, decisions can be made to harden the physical network and improve communication between stakeholders. This paper examines the parallel chains of oversight and custody as well as the chain of stakeholder interests for the shipments of SNF/HLW and the potential impacts on systemic resiliency. Using the Crystal River shutdown location as well as a hypothetical international shipment brought into the United States, this paper illustrates the parallel chains and maps them out visually.« less

Pyoderma gangrenosum-like ulcer in a patient with X-linked agammaglobulinemia: identification of Helicobacter bilis by mass spectrometry analysis.

PubMed

Murray, Patrick R; Jain, Ashish; Uzel, Gulbu; Ranken, Raymond; Ivy, Cristina; Blyn, Lawrence B; Ecker, David J; Sampath, Rangarajan; Lee, Chyi-Chia Richard; Turner, Maria L

2010-05-01

Pyoderma gangrenosum-like ulcers and cellulitis of the lower extremities associated with recurrent fevers in patients with X-linked (Bruton) agammaglobulinemia have been reported to be caused by Helicobacter bilis (formerly classified as Flexispira rappini and then Helicobacter strain flexispira taxon 8). Consistent themes in these reports are the difficulty in recovering this organism in blood and wound cultures and in maintaining isolates in vitro. We confirmed the presence of this organism in a patient's culture by using a novel application of gene amplification polymerase chain reaction and electrospray ionization time-of-flight mass spectrometry. An adolescent boy with X-linked agammaglobulinemia presented with indurated plaques and a chronic leg ulcer whose origin was strongly suspected to be an H bilis organism. Histologic analysis demonstrated positive Warthin-Starry staining of curvilinear rods, which grew in culture but failed to grow when subcultured. They could not be identified by conventional techniques. A combination of gene amplification by polymerase chain reaction and electrospray ionization time-of-flight mass spectrometry confirmed the identity of this organism. This novel technology was useful in the identification of a difficult-to-grow Helicobacter organism, the cause of pyoderma gangrenosum-like leg ulcers in patients with X-linked agammaglobulinemia. Correct identification of this organism as the cause of pyoderma gangrenosum-like ulcers in patients with X-linked agammaglobulinemia is of great importance for the early initiation of appropriate and curative antibiotic therapy.

Pyoderma Gangrenosum–Like Ulcer in a Patient With X-Linked Agammaglobulinemia

PubMed Central

Murray, Patrick R.; Jain, Ashish; Uzel, Gulbu; Ranken, Raymond; Ivy, Cristina; Blyn, Lawrence B.; Ecker, David J.; Sampath, Rangarajan; Lee, Chyi-Chia Richard; Turner, Maria L.

2011-01-01

Background Pyoderma gangrenosum–like ulcers and cellulitis of the lower extremities associated with recurrent fevers in patients with X-linked (Bruton) agammaglobulinemia have been reported to be caused by Helicobacter bilis (formerly classified as Flexispira rappini and then Helicobacter strain flexispira taxon 8). Consistent themes in these reports are the difficulty in recovering this organism in blood and wound cultures and in maintaining isolates in vitro. We confirmed the presence of this organism in a patient’s culture by using a novel application of gene amplification polymerase chain reaction and electrospray ionization time-of-flight mass spectrometry. Observation An adolescent boy with X-linked agammaglobulinemia presented with indurated plaques and a chronic leg ulcer whose origin was strongly suspected to be an H bilis organism. Histologic analysis demonstrated positive Warthin-Starry staining of curvilinear rods, which grew in culture but failed to grow when sub-cultured. They could not be identified by conventional techniques. A combination of gene amplification by polymerase chain reaction and electrospray ionization time-of-flight mass spectrometry confirmed the identity of this organism. Conclusions This novel technology was useful in the identification of a difficult-to-grow Helicobacter organism, the cause of pyoderma gangrenosum–like leg ulcers in patients with X-linked agammaglobulinemia. Correct identification of this organism as the cause of pyoderma gangrenosum–like ulcers in patients with X-linked agammaglobulinemia is of great importance for the early initiation of appropriate and curative antibiotic therapy. PMID:20479300

Local excitation-inhibition ratio for synfire chain propagation in feed-forward neuronal networks

NASA Astrophysics Data System (ADS)

Guo, Xinmeng; Yu, Haitao; Wang, Jiang; Liu, Jing; Cao, Yibin; Deng, Bin

2017-09-01

A leading hypothesis holds that spiking activity propagates along neuronal sub-populations which are connected in a feed-forward manner, and the propagation efficiency would be affected by the dynamics of sub-populations. In this paper, how the interaction between local excitation and inhibition effects on synfire chain propagation in feed-forward network (FFN) is investigated. The simulation results show that there is an appropriate excitation-inhibition (EI) ratio maximizing the performance of synfire chain propagation. The optimal EI ratio can significantly enhance the selectivity of FFN to synchronous signals, which thereby increases the stability to background noise. Moreover, the effect of network topology on synfire chain propagation is also investigated. It is found that synfire chain propagation can be maximized by an optimal interlayer linking probability. We also find that external noise is detrimental to synchrony propagation by inducing spiking jitter. The results presented in this paper may provide insights into the effects of network dynamics on neuronal computations.

Oligomerization of deoxynucleoside-biphosphate dimers - Template and linkage specificity

NASA Technical Reports Server (NTRS)

Visscher, J.; Van Der Woerd, R.; Bakker, C. G.; Schwartz, Alan W.

1989-01-01

The oligomerization of the activated 3-prime-5-prime pyrophosphate-linked dimer, pdAppdAp, is presently noted to be selectively favored by a poly(U) template over the 3-prime-3-prime and 5-prime-5-prime linked dimers. Both overall yields and the production of the longest oligomers were markedly stimulated by poly(U)'s presence; in its absence, the 5-prime-5-prime linked dimer became the most reactive, yielding chains of the order of 60 monomer-unit lengths. Remarkable self-organization properties are noted for the 5-prime-5-prime dimer of pdAp.

Linear ubiquitin chains: enzymes, mechanisms and biology

PubMed Central

2017-01-01

Ubiquitination is a versatile post-translational modification that regulates a multitude of cellular processes. Its versatility is based on the ability of ubiquitin to form multiple types of polyubiquitin chains, which are recognized by specific ubiquitin receptors to induce the required cellular response. Linear ubiquitin chains are linked through Met 1 and have been established as important players of inflammatory signalling and apoptotic cell death. These chains are generated by a ubiquitin E3 ligase complex called the linear ubiquitin chain assembly complex (LUBAC) that is thus far the only E3 ligase capable of forming linear ubiquitin chains. The complex consists of three subunits, HOIP, HOIL-1L and SHARPIN, each of which have specific roles in the observed biological functions of LUBAC. Furthermore, LUBAC has been found to be associated with OTULIN and CYLD, deubiquitinases that disassemble linear chains and counterbalance the E3 ligase activity of LUBAC. Gene mutations in HOIP, HOIL-1L and OTULIN are found in human patients who suffer from autoimmune diseases, and HOIL-1L mutations are also found in myopathy patients. In this paper, we discuss the mechanisms of linear ubiquitin chain generation and disassembly by their respective enzymes and review our current understanding of their biological functions and association with human diseases. PMID:28446710

Linear ubiquitin chains: enzymes, mechanisms and biology.

PubMed

Rittinger, Katrin; Ikeda, Fumiyo

2017-04-01

Ubiquitination is a versatile post-translational modification that regulates a multitude of cellular processes. Its versatility is based on the ability of ubiquitin to form multiple types of polyubiquitin chains, which are recognized by specific ubiquitin receptors to induce the required cellular response. Linear ubiquitin chains are linked through Met 1 and have been established as important players of inflammatory signalling and apoptotic cell death. These chains are generated by a ubiquitin E3 ligase complex called the linear ubiquitin chain assembly complex (LUBAC) that is thus far the only E3 ligase capable of forming linear ubiquitin chains. The complex consists of three subunits, HOIP, HOIL-1L and SHARPIN, each of which have specific roles in the observed biological functions of LUBAC. Furthermore, LUBAC has been found to be associated with OTULIN and CYLD, deubiquitinases that disassemble linear chains and counterbalance the E3 ligase activity of LUBAC. Gene mutations in HOIP, HOIL-1L and OTULIN are found in human patients who suffer from autoimmune diseases, and HOIL-1L mutations are also found in myopathy patients. In this paper, we discuss the mechanisms of linear ubiquitin chain generation and disassembly by their respective enzymes and review our current understanding of their biological functions and association with human diseases. © 2017 The Authors.

Ice core profiles of saturated fatty acids (C12:0-C30:0) and oleic acid (C18:1) from southern Alaska since 1734 AD: A link to climate change in the Northern Hemisphere

NASA Astrophysics Data System (ADS)

Pokhrel, Ambarish; Kawamura, Kimitaka; Seki, Osamu; Matoba, Sumio; Shiraiwa, Takayuki

2015-01-01

An ice core drilled at Aurora Peak in southeast Alaska was analyzed for homologous series of straight chain fatty acids (C12:0-C30:0) including unsaturated fatty acid (oleic acid) using gas chromatography (GC/FID) and GC/mass spectrometry (GC/MS). Molecular distributions of fatty acids are characterized by even carbon number predominance with a peak at palmitic acid (C16:0, av. 20.3 ± SD. 29.8 ng/g-ice) followed by oleic acid (C18:1, 19.6 ± 38.6 ng/g-ice) and myristic acid (C14:0, 15.3 ± 21.9 ng/g-ice). The historical trends of short-chain fatty acids, together with correlation analysis with inorganic ions and organic tracers suggest that short-chain fatty acids (except for C12:0 and C15:0) were mainly derived from sea surface micro layers through bubble bursting mechanism and transported over the glacier through the atmosphere. This atmospheric transport process is suggested to be linked with Kamchatka ice core δD record from Northeast Asia and Greenland Temperature Anomaly (GTA). In contrast, long-chain fatty acids (C20:0-C30:0) are originated from terrestrial higher plants, soil organic matter and dusts, which are also linked with GTA. Hence, this study suggests that Alaskan fatty acids are strongly influenced by Pacific Decadal Oscillation/North Pacific Gyre Oscillation and/or extra tropical North Pacific surface climate and Arctic oscillation. We also found that decadal scale variability of C18:1/C18:0 ratios in the Aurora Peak ice core correlate with the Kamchatka ice core δD, which reflects climate oscillations in the North Pacific. This study suggests that photochemical aging of organic aerosols could be controlled by climate periodicity.

Preparation and Cross-Linking of All-Acrylamide Diblock Copolymer Nano-Objects via Polymerization-Induced Self-Assembly in Aqueous Solution

PubMed Central

2017-01-01

Various carboxylic acid-functionalized poly(N,N-dimethylacrylamide) (PDMAC) macromolecular chain transfer agents (macro-CTAs) were chain-extended with diacetone acrylamide (DAAM) by reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization at 70 °C and 20% w/w solids to produce a series of PDMAC–PDAAM diblock copolymer nano-objects via polymerization-induced self-assembly (PISA). TEM studies indicate that a PDMAC macro-CTA with a mean degree of polymerization (DP) of 68 or higher results in the formation of well-defined spherical nanoparticles with mean diameters ranging from 40 to 150 nm. In contrast, either highly anisotropic worms or polydisperse vesicles are formed when relatively short macro-CTAs (DP = 40–58) are used. A phase diagram was constructed to enable accurate targeting of pure copolymer morphologies. Dynamic light scattering (DLS) and aqueous electrophoresis studies indicated that in most cases these PDMAC–PDAAM nano-objects are surprisingly resistant to changes in either solution pH or temperature. However, PDMAC40–PDAAM99 worms do undergo partial dissociation to form a mixture of relatively short worms and spheres on adjusting the solution pH from pH 2–3 to around pH 9 at 20 °C. Moreover, a change in copolymer morphology from worms to a mixture of short worms and vesicles was observed by DLS and TEM on heating this worm dispersion to 50 °C. Postpolymerization cross-linking of concentrated aqueous dispersions of PDMAC–PDAAM spheres, worms, or vesicles was performed at ambient temperature using adipic acid dihydrazide (ADH), which reacts with the hydrophobic ketone-functionalized PDAAM chains. The formation of hydrazone groups was monitored by FT-IR spectroscopy and afforded covalently stabilized nano-objects that remained intact on exposure to methanol, which is a good solvent for both blocks. Rheological studies indicated that the cross-linked worms formed a stronger gel compared to linear precursor worms. PMID:28260814

SARS hCoV papain-like protease is a unique Lys48 linkage-specific di-distributive deubiquitinating enzyme

PubMed Central

Békés, Miklós; Rut, Wioletta; Kasperkiewicz, Paulina; Mulder, Monique P. C.; Ovaa, Huib; Drag, Marcin; Lima, Christopher D.; Huang, Tony T.

2015-01-01

Ubiquitin (Ub) and the ubiquitin-like modifier interferon stimulated gene 15 (ISG15) participate in the host defense of viral infections. Viruses, including the Severe Acute Respiratory Syndrome human coronavirus (SARS hCoV), have co-opted Ub/ISG15-conjugation pathways for their own advantage or have evolved effector proteins to counter pro-inflammatory properties of Ub/ISG15-conjugated host proteins. Here, we compare substrate specificities of the papain-like protease (PLpro) from the recently emerged Middle Eastern Respiratory Syndrome (MERS) hCoV to the related protease from SARS, SARS PLpro. Through biochemical assays, we show that similar to SARS PLpro, MERS PLpro is both a deubiquitinating and a deISGylating enzyme. Further analysis of the intrinsic deubiquitinating enzyme (DUB) activity of these viral proteases revealed unique differences between the recognition and cleavage specificities of polyUb chains. First, MERS PLpro shows broad linkage specificity for the cleavage of polyUb chains, while SARS PLpro prefers to cleave Lys48-linked polyUb chains. Second, MERS PLpro cleaves polyUb chains in a “mono-distributive” manner (one Ub at a time), and SARS PLpro prefers to cleave K48-linked poly-Ub chains by sensing a di-Ub moiety as a minimal recognition element using a “di-distributive” cleavage mechanism. The di-distributive cleavage mechanism for SARS PLpro appears to be uncommon among USP-family DUBs, as related USP family members from humans do not display such a mechanism. We propose that these intrinsic enzymatic differences between SARS and MERS PLpro will help identify pro-inflammatory substrates of these viral DUBs and can guide in the design of therapeutics to combat infection by coronaviruses. PMID:25764917

SARS hCoV papain-like protease is a unique Lys48 linkage-specific di-distributive deubiquitinating enzyme.

PubMed

Békés, Miklós; Rut, Wioletta; Kasperkiewicz, Paulina; Mulder, Monique P C; Ovaa, Huib; Drag, Marcin; Lima, Christopher D; Huang, Tony T

2015-06-01

Ubiquitin (Ub) and the Ub-like (Ubl) modifier interferon-stimulated gene 15 (ISG15) participate in the host defence of viral infections. Viruses, including the severe acute respiratory syndrome human coronavirus (SARS hCoV), have co-opted Ub-ISG15 conjugation pathways for their own advantage or have evolved effector proteins to counter pro-inflammatory properties of Ub-ISG15-conjugated host proteins. In the present study, we compare substrate specificities of the papain-like protease (PLpro) from the recently emerged Middle East respiratory syndrome (MERS) hCoV to the related protease from SARS, SARS PLpro. Through biochemical assays, we show that, similar to SARS PLpro, MERS PLpro is both a deubiquitinating (DUB) and a deISGylating enzyme. Further analysis of the intrinsic DUB activity of these viral proteases revealed unique differences between the recognition and cleavage specificities of polyUb chains. First, MERS PLpro shows broad linkage specificity for the cleavage of polyUb chains, whereas SARS PLpro prefers to cleave Lys48-linked polyUb chains. Secondly, MERS PLpro cleaves polyUb chains in a 'mono-distributive' manner (one Ub at a time) and SARS PLpro prefers to cleave Lys48-linked polyUb chains by sensing a di-Ub moiety as a minimal recognition element using a 'di-distributive' cleavage mechanism. The di-distributive cleavage mechanism for SARS PLpro appears to be uncommon among USP (Ub-specific protease)-family DUBs, as related USP family members from humans do not display such a mechanism. We propose that these intrinsic enzymatic differences between SARS and MERS PLpro will help to identify pro-inflammatory substrates of these viral DUBs and can guide in the design of therapeutics to combat infection by coronaviruses.

Role of antennary structure of N-linked sugar chains in renal handling of recombinant human erythropoietin.

PubMed

Misaizu, T; Matsuki, S; Strickland, T W; Takeuchi, M; Kobata, A; Takasaki, S

1995-12-01

To elucidate the role of the branched structure of sugar chains of human erythropoietin (EPO) in the expression of in vivo activity, the pharmacokinetic profile of a less active recombinant human EPO sample (EPO-bi) enriched with biantennary sugar chains was compared with that of a highly active control EPO sample enriched with tetraantennary sugar chains. After an intravenous injection in rats, 125I-EPO-bi disappeared from the plasma with 3.2 times greater total body clearance (Cltot) than control 125I-EPO. Whole-body autoradiography after 20 minutes of administration indicated that the overall distribution of radioactivity is similar, but 125I-EPO-bi showed a higher level of radioactivity in the kidneys than control 125I-EPO. Quantitative determination of radioactivity in the tissues also indicated that radioactivity of 125I-EPO-bi in the kidneys was two times higher than that of control 125I-EPO. The difference in plasma disappearance between 125I-EPO-bi and control 125I-EPO was not observed in bilaterally nephrectomized rats. The distribution of 125I-EPO-bi to bone marrow and spleen was similarly inhibited by simultaneous injection of excess amounts of either the nonlabeled EPO-bi or control EPO. These results indicate that the low in vivo biologic activity of EPO-bi results from rapid clearance from the systemic circulation by renal handling. Thus, the well-branched structure of the N-linked sugar chain of EPO is suggested to play an important role in maintaining its higher plasma level, which guarantees an effective transfer to target organs and stimulation of erythroid progenitor cells.

Aqua­{6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato}nickel(II)

PubMed Central

Guo, Zhenghua; Li, Lianzhi; Xu, Tao; Li, Jinghong; Wang, Daqi

2009-01-01

The title complex, [Ni(C18H18N2O4)(H2O)], lies on a mirror plane with the NiII ion coordinated by two N and two O atoms of a tetra­dentate Schiff base ligand and one water O atom in a distorted square-pyramidal enviroment. The –CH2–CH2– group of the ligand is disordered equally over two sites about the mirror plane. The dihedral angle between the mean planes of the two symmetry-related chelate rings is 37.16 (6)°. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds link complex mol­ecules into one-dimensional chains along [100] and these chains are linked, in turn, by very weak inter­molecular C—H⋯O hydrogen bonds into a two-dimensional network. PMID:21577698

Crystal structure of 3-(adamantan-1-yl)-4-(4-chloro-phen-yl)-1H-1,2,4-triazole-5(4H)-thione.

PubMed

Al-Wabli, Reem I; El-Emam, Ali A; Alroqi, Obaid S; Chidan Kumar, C S; Fun, Hoong-Kun

2015-02-01

The title compound, C18H20ClN3S, is a functionalized triazoline-3-thione derivative. The benzene ring is almost perpendic-ular to the planar 1,2,4-triazole ring [maximum deviation = 0.007 (1) Å] with a dihedral angle of 89.61 (5)° between them and there is an adamantane substituent at the 3-position of the triazole-thione ring. In the crystal, N-H⋯S hydrogen-bonding inter-actions link the mol-ecules into chains extending along the c-axis direction. The crystal packing is further stabilized by weak C-H⋯π inter-actions that link adjacent chains into a two-dimensional structure in the bc plane. The crystal studied was an inversion twin with a 0.50 (3):0.50 (3) domain ratio.

Crystal structure of (E)-2-hy-droxy-4'-meth-oxy-aza-stilbene.

PubMed

Chantrapromma, Suchada; Kaewmanee, Narissara; Boonnak, Nawong; Chantrapromma, Kan; Ghabbour, Hazem A; Fun, Hoong-Kun

2015-06-01

The title aza-stilbene derivative, C14H13NO2 {systematic name: (E)-2-[(4-meth-oxy-benzyl-idene)amino]-phenol}, is a product of the condensation reaction between 4-meth-oxy-benzaldehyde and 2-amino-phenol. The mol-ecule adopts an E conformation with respect to the azomethine C=N bond and is almost planar, the dihedral angle between the two substituted benzene rings being 3.29 (4)°. The meth-oxy group is coplanar with the benzene ring to which it is attached, the Cmeth-yl-O-C-C torsion angle being -1.14 (12)°. There is an intra-molecular O-H⋯N hydrogen bond generating an S(5) ring motif. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming zigzag chains along [10-1]. The chains are linked via C-H⋯π inter-actions, forming a three-dimensional structure.

Controlled Shape Memory Behavior of a Smectic Main-Chain Liquid Crystalline Elastomer

DOE PAGES

Li, Yuzhan; Pruitt, Cole; Rios, Orlando; ...

2015-04-10

Here, we describe how a smectic main-chain liquid crystalline elastomer (LCE), with controlled shape memory behavior, is synthesized by polymerizing a biphenyl-based epoxy monomer with an aliphatic carboxylic acid curing agent. Microstructures of the LCEs, including their liquid crystallinity and cross-linking density, are modified by adjusting the stoichiometric ratio of the reactants to tailor the thermomechanical properties and shape memory behavior of the material. Thermal and liquid crystalline properties of the LCEs, characterized using differential scanning calorimetry and dynamic mechanical analysis, and structural analysis, performed using small-angle and wide-angle X-ray scattering, show that liquid crystallinity, cross-linking density, and network rigiditymore » are strongly affected by the stoichiometry of the curing reaction. With appropriate structural modifications it is possible to tune the thermal, dynamic mechanical, and thermomechanical properties as well as the shape memory and thermal degradation behavior of LCEs.« less

Controlled Shape Memory Behavior of a Smectic Main-Chain Liquid Crystalline Elastomer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yuzhan; Pruitt, Cole; Rios, Orlando

Here, we describe how a smectic main-chain liquid crystalline elastomer (LCE), with controlled shape memory behavior, is synthesized by polymerizing a biphenyl-based epoxy monomer with an aliphatic carboxylic acid curing agent. Microstructures of the LCEs, including their liquid crystallinity and cross-linking density, are modified by adjusting the stoichiometric ratio of the reactants to tailor the thermomechanical properties and shape memory behavior of the material. Thermal and liquid crystalline properties of the LCEs, characterized using differential scanning calorimetry and dynamic mechanical analysis, and structural analysis, performed using small-angle and wide-angle X-ray scattering, show that liquid crystallinity, cross-linking density, and network rigiditymore » are strongly affected by the stoichiometry of the curing reaction. With appropriate structural modifications it is possible to tune the thermal, dynamic mechanical, and thermomechanical properties as well as the shape memory and thermal degradation behavior of LCEs.« less

Killing of cultured hepatocytes by conjugates of asialofetuin and EGF linked to the A chains of ricin or diphtheria toxin.

PubMed

Simpson, D L; Cawley, D B; Herschman, H R

1982-06-01

A disulfide-linked conjugate between asialofetuin (ASF) and the toxic A chain (RTA) of ricin is as potent a toxin for cultured rat hepatocytes as our previously described conjugate between ASF and fragment A of diphtheria toxin (DTA). An RTA conjugate of epidermal growth factor (EGF) was a potent toxin for 3T3 cells. In contrast, EGF-DTA was essentially nontoxic for 3T3 cells. We have now examined the toxicity of EGF-RTA and EGF-DTA on cultured hepatocytes. The EGF-DTA conjugate, nontoxic to 3T3 cells, is also a potent toxin for hepatocytes. We also observed a decrease with time of culture in the sensitivity of hepatocytes to the ASF and EGF conjugates. This decrease is not a result of a decrease in EGF or asialoglycoprotein receptors.

Crystal structure of (3S*,4R*)-4-fluoro-3-(4-meth-oxy-phen-yl)-1-oxo-2-phenyl-1,2,3,4-tetra-hydro-iso-quinoline-4-carb-oxy-lic acid.

PubMed

Lehmann, Anna; Lechner, Lisa; Radacki, Krzysztof; Braunschweig, Holger; Holzgrabe, Ulrike

2017-06-01

The title compound, C 23 H 18 FNO 4 , crystallized as a racemate. It exhibits a cis conformation with respect to the F atom and the methine H atom. The piperidine ring has a screw-boat conformation. The meth-oxy-phenyl ring and the phenyl ring are inclined to the mean plane of the iso-quinoline ring system by 89.85 (4) and 46.62 (5)°, respectively, and by 78.15 (5)° to one another. In the crystal, mol-ecules are linked by an O-H⋯O hydrogen bond forming chains propagating along the a -axis direction. The chains are linked by C-H⋯F hydrogen bonds, forming layers lying parallel to the ab plane.

Interfacial Properties of Thin Films of Poly(vinyl ether)s with Architectural Design in Water

NASA Astrophysics Data System (ADS)

Oda, Yukari; Itagaki, Nozomi; Sugimoto, Sin; Kawaguchi, Daisuke; Matsuno, Hisao; Tanaka, Keiji

Precise design of primary structure and architecture of polymers leads to the well-defined structure, unique physical properties, and excellent functions not only in the bulk but also at the interfaces. We here constructed functional polymer interfaces in water based on the architectural design of poly(vinyl ether)s with oxyethylene side-chains (POEVE). A branched polymer with POEVE parts was preferentially segregated at the air interface in the matrix of poly(methyl methacrylate). As an alternative way to prepare the POEVE surface, the cross-linked hydrogel thin films were prepared. The moduli of the hydrogel films near the water interfaces, which were examined by force-distance curve measurements using atomic force microscopy, were greatly sensitive to the cross-linking density of the polymers. Diffuse interfaces of POEVE chains at the water interface make it possible to prevent the platelet adhesion on the films.

Linking earth science informatics resources into uninterrupted digital value chains

NASA Astrophysics Data System (ADS)

Woodcock, Robert; Angreani, Rini; Cox, Simon; Fraser, Ryan; Golodoniuc, Pavel; Klump, Jens; Rankine, Terry; Robertson, Jess; Vote, Josh

2015-04-01

The CSIRO Mineral Resources Flagship was established to tackle medium- to long-term challenges facing the Australian mineral industry across the value chain from exploration and mining through mineral processing within the framework of an economically, environmentally and socially sustainable minerals industry. This broad portfolio demands collaboration and data exchange with a broad range of participants and data providers across government, research and industry. It is an ideal environment to link geoscience informatics platforms to application across the resource extraction industry and to unlock the value of data integration between traditionally discrete parts of the minerals digital value chain. Despite the potential benefits, data integration remains an elusive goal within research and industry. Many projects use only a subset of available data types in an integrated manner, often maintaining the traditional discipline-based data 'silos'. Integrating data across the entire minerals digital value chain is an expensive proposition involving multiple disciplines and, significantly, multiple data sources both internal and external to any single organisation. Differing vocabularies and data formats, along with access regimes to appropriate analysis software and equipment all hamper the sharing and exchange of information. AuScope has addressed the challenge of data exchange across organisations nationally, and established a national geosciences information infrastructure using open standards-based web services. Federated across a wide variety of organisations, the resulting infrastructure contains a wide variety of live and updated data types. The community data standards and infrastructure platforms that underpin AuScope provide important new datasets and multi-agency links independent of software and hardware differences. AuScope has thus created an infrastructure, a platform of technologies and the opportunity for new ways of working with and integrating disparate data at much lower cost. An early example of this approach is the value generated by combining geological and metallurgical data sets as part of the rapidly growing field of geometallurgy. This not only provides a far better understanding of the impact of geological variability on ore processing but also leads to new thinking on the types and characteristics of data sets collected at various stages of the exploration and mining process. The Minerals Resources Flagship is linking its research activities to the AuScope infrastructure, exploiting the technology internally to create a platform for integrated research across the minerals value chain and improved interaction with industry. Referred to as the 'Early Access Virtual Lab', the system will be fully interoperable with AuScope and international infrastructures using open standards like GeosciML. Secured access is provided to allow confidential collaboration with industry when required. This presentation will discuss how the CSIRO Mineral Resources Flagship is building on the AuScope infrastructure to transform the way that data and data products are identified, shared, integrated, and reused, to unlock the benefits of true integration of research efforts across the minerals digital value chain.

Translation and assembly of HLA-DR antigens in Xenopus oocytes injected with mRNA from a human B-cell line.

PubMed Central

Long, E O; Gross, N; Wake, C T; Mach, J P; Carrel, S; Accolla, R; Mach, B

1982-01-01

HLA-DR antigens are polymorphic cell surface glycoproteins, expressed primarily in B lymphocytes and macrophages, which are thought to play an important role in the immune response. Two polypeptide chains, alpha and beta, are associated at the cell surface, and a third chain associates with alpha and beta intracellularly. RNA isolated from the human B-cell line Raji was injected in Xenopus laevis oocytes. Immunoprecipitates of translation products with several monoclonal antibodies revealed the presence of HLA-DR antigens similar to those synthesized in Raji cells. One monoclonal antibody was able to bind the beta chain after dissociation of the three polypeptide chains with detergent. The presence of all three chains was confirmed by two-dimensional gel electrophoresis. The glycosylation pattern of the three chains was identical to that observed in vivo, as evidenced in studies using tunicamycin, an inhibitor of N-linked glycosylation. The presence of alpha chains assembled with beta chains in equimolar ratio was further demonstrated by amino-terminal sequencing. An RNA fraction enriched for the three mRNAs, encoding alpha, beta, and intracellular chains, was isolated. This translation-assembly system and the availability of monoclonal antibodies make it possible to assay for mRNA encoding specific molecules among the multiple human Ia-like antigens. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:6821356

Molecular Strategies for Morphology Control in Semiconducting Polymers for Optoelectronics.

PubMed

Rahmanudin, Aiman; Sivula, Kevin

2017-06-28

Solution-processable semiconducting polymers have been explored over the last decades for their potential applications in inexpensively fabricated transistors, diodes and photovoltaic cells. However, a remaining challenge in the field is to control the solid-state self-assembly of polymer chains in thin films devices, as the aspects of (semi)crystallinity, grain boundaries, and chain entanglement can drastically affect intra-and inter-molecular charge transport/transfer and thus device performance. In this short review we examine how the aspects of molecular weight and chain rigidity affect solid-state self-assembly and highlight molecular engineering strategies to tune thin film morphology. Side chain engineering, flexibly linking conjugation segments, and block co-polymer strategies are specifically discussed with respect to their effect on field effect charge carrier mobility in transistors and power conversion efficiency in solar cells. Example systems are taken from recent literature including work from our laboratories to illustrate the potential of molecular engineering semiconducting polymers.

Simultaneous covalent and noncovalent hybrid polymerizations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Z.; Tantakitti, F.; Yu, T.

Covalent and supramolecular polymers are two distinct forms of soft matter, composed of long chains of covalently and noncovalently linked structural units, respectively. We report a hybrid system formed by simultaneous covalent and supramolecular polymerizations of monomers. The process yields cylindrical fibers of uniform diameter that contain covalent and supramolecular compartments, a morphology not observed when the two polymers are formed independently. The covalent polymer has a rigid aromatic imine backbone with helicoidal conformation, and its alkylated peptide side chains are structurally identical to the monomer molecules of supramolecular polymers. In the hybrid system, covalent chains grow to higher averagemore » molar mass relative to chains formed via the same polymerization in the absence of a supramolecular compartment. The supramolecular compartments can be reversibly removed and re-formed to reconstitute the hybrid structure, suggesting soft materials with novel delivery or repair functions.« less

Antibody-Directed Cytotoxic Agents: Use of Monoclonal Antibody to Direct the Action of Toxin A Chains to Colorectal Carcinoma Cells

NASA Astrophysics Data System (ADS)

Gilliland, D. Gary; Steplewski, Zenon; Collier, R. John; Mitchell, Kenneth F.; Chang, Tong H.; Koprowski, Hilary

1980-08-01

We have constructed cell-specific cytotoxic agents by covalently coupling the A chain from diphtheria toxin or ricin toxin to monoclonal antibody directed against a colorectal carcinoma tumor-associated antigen. Antibody 1083-17-1A was modified by attachment of 3-(2-pyridyldithio)propionyl or cystaminyl groups and then treated with reduced A chain to give disulfide-linked conjugates that retained the original binding specificity of the antibody moiety. The conjugates showed cytotoxic activity for colorectal carcinoma cells in culture, but were not toxic in the same concentration range for a variety of cell lines that lacked the antigen. Under defined conditions virtually 100% of antigen-bearing cultured cells were killed, whereas cells that lacked the antigen were not affected. Conjugates containing toxin A chains coupled to monoclonal antibodies may be useful in studying functions of various cell surface components and, possibly, as tumor-specific therapeutic agents.

Microscopic insights into the NMR relaxation based protein conformational entropy meter

PubMed Central

Kasinath, Vignesh; Sharp, Kim A.; Wand, A. Joshua

2013-01-01

Conformational entropy is a potentially important thermodynamic parameter contributing to protein function. Quantitative measures of conformational entropy are necessary for an understanding of its role but have been difficult to obtain. An empirical method that utilizes changes in conformational dynamics as a proxy for changes in conformational entropy has recently been introduced. Here we probe the microscopic origins of the link between conformational dynamics and conformational entropy using molecular dynamics simulations. Simulation of seven pro! teins gave an excellent correlation with measures of side-chain motion derived from NMR relaxation. The simulations show that the motion of methyl-bearing side-chains are sufficiently coupled to that of other side chains to serve as excellent reporters of the overall side-chain conformational entropy. These results tend to validate the use of experimentally accessible measures of methyl motion - the NMR-derived generalized order parameters - as a proxy from which to derive changes in protein conformational entropy. PMID:24007504

Photophysical and lasing properties of new analogs of the boron-dipyrromethene laser dye pyrromethene 567 incorporated into or covalently bounded to solid matrices of poly(methyl methacrylate).

PubMed

López Arbeloa, F; Bañuelos Prieto, J; López Arbeloa, I; Costela, A; García-Moreno, I; Gómez, C; Amat-Guerri, F; Liras, M; Sastre, R

2003-07-01

The photophysical, lasing and thermostability properties of newly synthesized analogs of the commercial dye pyrromethene 567 (PM567) have been measured in polymeric matrices of poly(methyl methacrylate) both when used as a dopant and when covalently bounded to the polymeric chain. These analogs have an acetoxy or a polymerizable methacryloyloxy group at the end of a polymethylene chain at Position 8 of the PM567 chromophore core. Clear correlations between photophysical and lasing characteristics are observed. Linking chain lengths with three or more methylene units give the highest fluorescence quantum yields (as high as 0.89) and lasing efficiencies (as high as 41%). The covalent linkage of the chromophore to the polymeric chain via the methacryloyloxy group improves the photostability of the PM567 chromophore.

A "simulation chain" to define a Multidisciplinary Decision Support System for landslide risk management in pyroclastic soils

NASA Astrophysics Data System (ADS)

Damiano, E.; Mercogliano, P.; Netti, N.; Olivares, L.

2012-04-01

This paper proposes a Multidisciplinary Decision Support System (MDSS) as an approach to manage rainfall-induced shallow landslides of the flow type (flowslides) in pyroclastic deposits. We stress the need to combine information from the fields of meteorology, geology, hydrology, geotechnics and economics to support the agencies engaged in land monitoring and management. The MDSS consists of a "simulation chain" to link rainfall to effects in terms of infiltration, slope stability and vulnerability. This "simulation chain" was developed at the Euro-Mediterranean Centre for Climate Change (CMCC) (meteorological aspects), at the Geotechnical Laboratory of the Second University of Naples (hydrological and geotechnical aspects) and at the Department of Economics of the University of Naples "Federico II" (economic aspects). The results obtained from the application of this simulation chain in the Cervinara area during eleven years of research allowed in-depth analysis of the mechanisms underlying a flowslide in pyroclastic soil.

Crystal structure and magnetic properties of a unique 3D coordination polymer constructed from flexible aliphatic tricarballylic acid ligands featuring linear trimeric Manganese(II)-based, metal carboxylate chains

NASA Astrophysics Data System (ADS)

Zou, Hua-Hong; Zhang, Shu-Hua; Zeng, Ming-Hua; Zhou, Yan-Ling; Liang, Hong

2008-08-01

A novel linear trimeric-based, Mn(II)-carboxylate chain well separated by long-linking flexible aliphatic tricarballylic acid ligands in a 3D coordination polymer [Mn 3(C 6H 5O 6) 2(H 2O) 4] n ( 1, C 6H 5O 6dbnd CH (COO -)(CH 2COO -) 2, TCA) exhibits low-dimensional antiferromagnetic order at 3.0 K. Such magnetic behavior is arises from the alternate Antiferro-Antiferro-Antiferro' ( J1J1J2) repeating interactions sequence, based on the nature of the binding modes of Mn(II)-carboxylate chain and the effect of interchains arrangement of 1. The reported carboxylate-bridged metal chain systems display a new structurally authenticated example of linear homometallic spin arranged antiferromagnet among metal carboxylates.

An ab initio molecular dynamics and density functional theory study of the formation of phosphate chains from metathiophosphates.

PubMed

Mosey, Nicholas J; Woo, Tom K

2006-09-04

The reactions that occur between metathiophosphate (MTP) molecules are identified and examined through ab initio molecular dynamics simulations and static quantum chemical calculations at the density functional level of theory. The simulations show that certain types of MTPs can react to yield phosphate chains, while others only dimerize. These differences are rationalized in terms of reaction energies and the electronic structures of these molecules. In the reaction leading to the formation of phosphate chains, the reactive center, a tri-coordinate phosphorus atom, is continually regenerated. A polymerization mechanism linking MTPs to phosphate chains is developed on the basis of these results. This information sheds light on the underlying processes that may be responsible for the formation of phosphates under high-temperature conditions and may prove useful in the development of protocols for the rational synthesis of complex phosphate structures.

Crystal structures of 3-fluoro-N-[2-(tri-fluoro-meth-yl)phen-yl]benzamide, 3-bromo-N-[2-(tri-fluoro-meth-yl)phen-yl]benzamide and 3-iodo-N-[2-(tri-fluoro-meth-yl)phen-yl]benzamide.

PubMed

Suchetan, P A; Suresha, E; Naveen, S; Lokanath, N K

2016-06-01

In the title compounds, C14H9F4NO, (I), C14H9BrF3NO, (II), and C14H9F3INO, (III), the two benzene rings are inclined to one another by 43.94 (8)° in mol-ecule A and 55.66 (7)° in mol-ecule B of compound (I), which crystallizes with two independent mol-ecules in the asymmetric unit, but by only 10.40 (12)° in compound (II) and 12.5 (2)° in compound (III). In the crystals of all three compounds, N-H⋯O hydrogen bonds link the mol-ecules to form chains propagating along the a-axis direction for (I), and along the b-axis direction for (II) and (III). In the crystal of (I), -A-B-A-B- chains are linked by C-H⋯O hydrogen bonds, forming layers parallel to (010). Within the layers there are weak offset π-π inter-actions present [inter-centroid distances = 3.868 (1) and 3.855 (1) Å]. In the crystals of (II) and (III), the chains are linked via short halogen-halogen contacts [Br⋯Br = 3.6141 (4) Å in (II) and I⋯I = 3.7797 (5) Å in (III)], resulting in the formation of ribbons propagating along the b-axis direction.

Sensitivity, specificity and comparison of three commercially available immunological tests in the diagnosis of Cryptosporidium species in animals.

PubMed

Danišová, Olga; Halánová, Monika; Valenčáková, Alexandra; Luptáková, Lenka

The study was conducted to compare the specificity of immunological diagnostic methods used for the diagnosis of Cryptosporidium species capable of causing life-threatening infection in both immunosuppressed and immunocompetent patients. For the detection of Cryptosporidium species in 79 animals with diarrhoea, we used three Copro-antigen tests: RIDASCREEN ® Cryptosporidium test, Cryptosporidium 2nd Generation (ELISA) and RIDA ® QUICK Cryptosporidium. For immunoassays we used positive and negative samples detected by means of polymerase chain reaction and validated by sequencing and nested polymerase chain reaction to confirm the presence six different species of Cryptosporidium species. Prevalence of cryptosporidiosis in the entire group determined by enzyme immunoassay, enzyme linked immunosorbent assay, immuno-chromatographic test and polymerase chain reaction was 34.17%, 27.84%, 6.33% and 27.84%, respectively. Sensitivity of animal samples with enzyme immunoassay, enzyme linked immunosorbent assay, and immuno-chromatographic test was 63.6%, 40.9% and 22.7%, resp., when questionable samples were considered positive, whereas specificity of enzyme immunoassay, enzyme linked immunosorbent assay and immuno-chromatographic test was 75.9%, 78.9% and 100%, respectively. Positive predictive values and negative predictive values were different for all the tests. These differences results are controversial and therefore reliability and reproducibility of immunoassays as the only diagnostic method is questionable. The use of various Cryptosporidium species in diagnosis based on immunological testing and different results obtained by individual tests indicate potential differences in Copro-antigens produced by individual Cryptosporidium species. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Oligosaccharide processing at individual glycosylation sites on MOPC 104E immunoglobulin M. Differences in alpha 1,2-linked mannose processing.

PubMed

Brown, P H; Hickman, S

1986-02-25

Processing of the asparagine-linked oligosaccharides at the known glycosylation sites on the mu-chain of IgM secreted by MOPC 104E murine plasmacytoma cells was investigated. Oligosaccharides present on intracellular mu-chain precursors were of the high mannose type, remaining susceptible to endo-beta-N-acetylglucosaminidase H. However, only 26% of the radioactivity was released from [3H]mannose-labeled secreted IgM glycopeptides, consistent with the presence of high mannose-type and complex-type oligosaccharides on the mature mu-chain. [3H]Mannose-labeled cyanogen bromide glycopeptides derived from mu-chains of secreted IgM were isolated and analyzed to identify the glycopeptide containing the high mannose-type oligosaccharide from those containing complex-type structures. [3H]Mannose-labeled intracellular mu-chain cyanogen bromide glycopeptides corresponding to those from secreted IgM were isolated also, and the time courses of oligosaccharide processing at the individual glycosylation sites were determined. The major oligosaccharides on all intracellular mu-chain glycopeptides after 20 min of pulse labeling with [3H]mannose were identified as Man8GlcNAc2, Man9GlcNAc2, and Glc1Man9GlcNAc2. Processing of the oligosaccharide destined to become the high mannose-type structure on the mature protein was rapid. After 30 min of chase incubation the predominant structures of this oligosaccharide were Man5GlcNAc2 and Man6GlcNAc2 which were also identified on the high mannose-type oligosaccharide of the secreted mu-chain. In contrast, processing of oligosaccharides destined to become complex type was considerably slower. Even after 180 min of chase incubation, Man7GlcNAc2 and Man8GlcNAc2 were the predominant structures at some of these glycosylation sites. The isomeric structures of Man8GlcNAc2 obtained from all of the glycosylation sites were identical. Thus, the different rates of processing were not the result of a different sequence of alpha 1,2-mannose removal.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Naisheng; Sen, Mani; Zeng, Wenduo

In this paper, we report a link between the interfacial structure and adhesive property of homopolymer chains physically adsorbed (i.e., via physisorption) onto solids. Polyethylene oxide (PEO) was used as a model and two different chain conformations of the adsorbed polymer were created on silicon substrates via the well-established Guiselin's approach: “flattened chains” which lie flat on the solid and are densely packed, and “loosely adsorbed polymer chains” which form bridges jointing up nearby empty sites on the solid surface and cover the flattened chains. We investigated the adhesion properties of the two different adsorbed chains using a custom-built adhesionmore » testing device. Bilayers of a thick PEO overlayer on top of the flattened chains or loosely adsorbed chains were subjected to the adhesion test. The results revealed that the flattened chains do not show any adhesion even with the chemically identical free polymer on top, while the loosely adsorbed chains exhibit adhesion. Neutron reflectivity experiments corroborated that the difference in the interfacial adhesion is not attributed to the interfacial brodening at the free polymer–adsorbed polymer interface. Instead, coarse-grained molecular dynamics simulation results suggest that the tail parts of the loosely adsorbed chains act as “connector molecules”, bridging the free chains and substrate surface and improving the interfacial adhesion. Finally, these findings not only shed light on the structure–property relationship at the interface, but also provide a novel approach for developing sticking/anti-sticking technologies through precise control of the interfacial polymer nanostructures.« less

Differential expression of human lysyl hydroxylase genes, lysine hydroxylation, and cross-linking of type I collagen during osteoblastic differentiation in vitro

NASA Technical Reports Server (NTRS)

Uzawa, K.; Grzesik, W. J.; Nishiura, T.; Kuznetsov, S. A.; Robey, P. G.; Brenner, D. A.; Yamauchi, M.

1999-01-01

The pattern of lysyl hydroxylation in the nontriple helical domains of collagen is critical in determining the cross-linking pathways that are tissue specific. We hypothesized that the tissue specificity of type I collagen cross-linking is, in part, due to the differential expression of lysyl hydroxylase genes (Procollagen-lysine,2-oxyglutarate,5-dioxygenase 1, 2, and 3 [PLOD1, PLOD2, and PLOD3]). In this study, we have examined the expression patterns of these three genes during the course of in vitro differentiation of human osteoprogenitor cells (bone marrow stromal cells [BMSCs]) and normal skin fibroblasts (NSFs). In addition, using the medium and cell layer/matrix fractions in these cultures, lysine hydroxylation of type I collagen alpha chains and collagen cross-linking chemistries have been characterized. High levels of PLOD1 and PLOD3 genes were expressed in both BMSCs and NSFs, and the expression levels did not change in the course of differentiation. In contrast to the PLOD1 and PLOD3 genes, both cell types showed low PLOD2 gene expression in undifferentiated and early differentiated conditions. However, fully differentiated BMSCs, but not NSFs, exhibited a significantly elevated level (6-fold increase) of PLOD2 mRNA. This increase coincided with the onset of matrix mineralization and with the increase in lysyl hydroxylation in the nontriple helical domains of alpha chains of type I collagen molecule. Furthermore, the collagen cross-links that are derived from the nontriple helical hydroxylysine-aldehyde were found only in fully differentiated BMSC cultures. The data suggests that PLOD2 expression is associated with lysine hydroxylation in the nontriple helical domains of collagen and, thus, could be partially responsible for the tissue-specific collagen cross-linking pattern.

Clotting of mammalian fibrinogens by papain: a re-examination.

PubMed

Doolittle, Russell F

2014-10-28

Papain has long been known to cause the gelation of mammalian fibrinogens. It has also been reported that papain-fibrin is insoluble in dispersing solvents like strong urea or sodium bromide solutions, similar to what is observed with thrombin-generated clots in the presence of factor XIIIa and calcium. In those old studies, both the gelation and subsequent clot stabilization were attributed to papain, although the possibility that the second step might be due to contaminating factor XIII in fibrinogen preparations was considered. I have revisited this problem in light of knowledge acquired over the past half-century about thiol proteases like papain, which mostly cleave peptide bonds, and transglutaminases like factor XIIIa that catalyze the formation of ε-lysyl-γ-glutamyl cross-links. Recombinant fibrinogen, inherently free of factor XIII and other plasma proteins, formed a stable gel when treated with papain alone. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the intermolecular cross-linking in papain-fibrin leads to γ-chain dimers, trimers, and tetramers, just as is the case with thrombin-factor XIIIa-stabilized fibrin. Mass spectrometry of bands excised from gels showed that the cross-linked material is quite different from what occurs with factor XIIIa, however. With papain, the cross-linking occurs between γ chains in neighboring protofibrils becoming covalently linked in a "head-to-tail" fashion by a transpeptidation reaction involving the α-amino group of γ-Tyr1 and a papain cleavage site at γ-Gly403 near the carboxy terminus, rather than by the (reciprocal) "tail-to-tail" manner that occurs with factor XIIIa and that depends on cross-links between γ-Lys406 and γ-Gln398.

Structural analysis of fructans from Agave americana grown in South Africa for spirit production.

PubMed

Ravenscroft, Neil; Cescutti, Paola; Hearshaw, Meredith A; Ramsout, Ronica; Rizzo, Roberto; Timme, Elizabeth M

2009-05-27

Fructans isolated from Agave americana grown in South Africa are currently used for spirit production. Structural studies on water-soluble fructans were performed to facilitate the development of other applications including its use as a prebiotic. Acid hydrolysis followed by HPAEC-PAD analysis confirmed that the fructan was composed of glucose and fructose, and size analysis by HPAEC-PAD and size exclusion chromatography indicated that the saccharides have a DP range from 6 to 50. An average DP of 14 was estimated by (1)H NMR analysis. Linkage analysis and ESI-MS studies suggest that A. americana has a neofructan structure consisting of a central sucrose to which (2 → 1)- and (2 → 6)-linked β-D-Fruf chains are attached. The (2 → 1)-linked units extend from C-1 of Fru and C-6 of glucose, whereas the (2 → 6)-linked β-D-Fruf units are attached to C-6 of the central Fru. This structure accounts for the presence of equimolar amounts of 1,6-linked Glu and 1,2,6-linked Fru found in linkage analysis and the multiplicity of the NMR signals observed. Detailed ESI-MS studies were performed on fructan fractions: native, periodate oxidized/reduced, and permethylated oligomers. These derivatizations introduced mass differences between Glc and Fru following oxidation and between 1,2-, 1,6-, 2,6-, and 1,2,6-linked units after methylation. Thus, ESI-MS showed the presence of a single Glc per fructan chain and that it is predominantly internal, rather than terminal as found in inulin. These structural features were confirmed by the use of 1D and 2D NMR experiments.

Silk Hydrogels of Tunable Structure and Viscoelastic Properties Using Different Chronological Orders of Genipin and Physical Cross-Linking.

PubMed

Elliott, Winston H; Bonani, Walter; Maniglio, Devid; Motta, Antonella; Tan, Wei; Migliaresi, Claudio

2015-06-10

Catering the hydrogel manufacturing process toward defined viscoelastic properties for intended biomedical use is important to hydrogel scaffolding function and cell differentiation. Silk fibroin hydrogels may undergo "physical" cross-linking through β-sheet crystallization during high pressure carbon dioxide treatment, or covalent "chemical" cross-linking by genipin. We demonstrate here that time-dependent mechanical properties are tunable in silk fibroin hydrogels by altering the chronological order of genipin cross-linking with β-sheet formation. Genipin cross-linking before β-sheet formation affects gelation mechanics through increased molecular weight, affecting gel morphology, and decreasing stiffness response. Alternately, genipin cross-linking after gelation anchored amorphous regions of the protein chain, and increasing stiffness. These differences are highlighted and validated through large amplitude oscillatory strain near physiologic levels, after incorporation of material characterization at molecular and micron length scales.

EPA EcoBox Tools by Exposure Pathways - Food Chains

EPA Pesticide Factsheets

Eco-Box is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

Linking Supply Chain Governance and Biosecurity in the Context of HPAI Control in Western Java: A Value Chain Perspective

PubMed Central

Indrawan, Dikky; Rich, Karl M.; van Horne, Peter; Daryanto, Arief; Hogeveen, Henk

2018-01-01

Despite extensive efforts to control the highly pathogenic avian influenza (HPAI), it remains endemic in Western Java, Indonesia. To understand the limited effectiveness of HPAI control measures, it is important to map the complex structure of the poultry sector. The governance of the poultry value chain in particular, could play a pivotal role, yet there is limited information on the different chain governance structures and their impacts on HPAI control. This article uses value chain analysis (VCA), focusing on an in-depth assessment of governance structures as well as transaction cost economics and quantitative estimates of the market power of different chain actors, to establish a theoretical framework to examine biosecurity and HPAI control in the Western Java poultry chain. During the research, semi-structured interviews were conducted with key value-chain stakeholders, and the economic performance of identified actors was estimated. Results indicated the co-existence of four different poultry value chains in West Java: the integrator chain, the semi-automated slaughterhouse chain, the controlled slaughter-point chain, and the private slaughter-point chain. The integrator chain was characterized by the highest levels of coordination and a tight, hierarchical governance. In contrast, the other three types of value chains were less coordinated. The market power of the different actors within the four value chains also differed. In more integrated chains, slaughterhouses held considerable market power, while in more informal value chains, market power was in the hands of traders. The economic effects of HPAI and biosecurity measures also varied for the identified actors in the different value chains. Implementation of biosecurity and HPAI control measures was strongly related to the governance structure of the chain, with interactions between different chains and governance structures accentuating the risk of HPAI. Our findings highlight that a proper understanding of the chain governance structure is vital to improve the effectiveness of HPAI control measures, by making the interventions more specific and fit-for-purpose given the incentive structures present in different chains. PMID:29770325

Linking Supply Chain Governance and Biosecurity in the Context of HPAI Control in Western Java: A Value Chain Perspective.

PubMed

Indrawan, Dikky; Rich, Karl M; van Horne, Peter; Daryanto, Arief; Hogeveen, Henk

2018-01-01

Despite extensive efforts to control the highly pathogenic avian influenza (HPAI), it remains endemic in Western Java, Indonesia. To understand the limited effectiveness of HPAI control measures, it is important to map the complex structure of the poultry sector. The governance of the poultry value chain in particular, could play a pivotal role, yet there is limited information on the different chain governance structures and their impacts on HPAI control. This article uses value chain analysis (VCA), focusing on an in-depth assessment of governance structures as well as transaction cost economics and quantitative estimates of the market power of different chain actors, to establish a theoretical framework to examine biosecurity and HPAI control in the Western Java poultry chain. During the research, semi-structured interviews were conducted with key value-chain stakeholders, and the economic performance of identified actors was estimated. Results indicated the co-existence of four different poultry value chains in West Java: the integrator chain, the semi-automated slaughterhouse chain, the controlled slaughter-point chain, and the private slaughter-point chain. The integrator chain was characterized by the highest levels of coordination and a tight, hierarchical governance. In contrast, the other three types of value chains were less coordinated. The market power of the different actors within the four value chains also differed. In more integrated chains, slaughterhouses held considerable market power, while in more informal value chains, market power was in the hands of traders. The economic effects of HPAI and biosecurity measures also varied for the identified actors in the different value chains. Implementation of biosecurity and HPAI control measures was strongly related to the governance structure of the chain, with interactions between different chains and governance structures accentuating the risk of HPAI. Our findings highlight that a proper understanding of the chain governance structure is vital to improve the effectiveness of HPAI control measures, by making the interventions more specific and fit-for-purpose given the incentive structures present in different chains.

Automatic detection of sweep-meshable volumes

DOEpatents

Tautges,; Timothy J. , White; David, R [Pittsburgh, PA

2006-05-23

A method of and software for automatically determining whether a mesh can be generated by sweeping for a representation of a geometric solid comprising: classifying surface mesh schemes for surfaces of the representation locally using surface vertex types; grouping mappable and submappable surfaces of the representation into chains; computing volume edge types for the representation; recursively traversing surfaces of the representation and grouping the surfaces into source, target, and linking surface lists; and checking traversal direction when traversing onto linking surfaces.

LaRC-RP41: A Tough, High-Performance Composite Matrix

NASA Technical Reports Server (NTRS)

Pater, Ruth H.; Johnston, Norman J.; Smith, Ricky E.; Snoha, John J.; Gautreaux, Carol R.; Reddy, Rakasi M.

1991-01-01

New polymer exhibits increased toughness and resistance to microcracking. Cross-linking PMR-15 and linear LaRC-TPI combined to provide sequential semi-2-IPN designated as LaRC-RP41. Synthesized from PMR-15 imide prepolymer undergoing cross-linking in immediate presence of LaRC-TPI polyamic acid, also undergoing simultaneous imidization and linear chain extension. Potentially high-temperature matrix resin, adhesive, and molding resin. Applications include automobiles, electronics, aircraft, and aerospace structures.

Occurrence of an Unusual Hopanoid-containing Lipid A Among Lipopolysaccharides from Bradyrhizobium Species*

PubMed Central

Komaniecka, Iwona; Choma, Adam; Mazur, Andrzej; Duda, Katarzyna A.; Lindner, Buko; Schwudke, Dominik; Holst, Otto

2014-01-01

The chemical structures of the unusual hopanoid-containing lipid A samples of the lipopolysaccharides (LPS) from three strains of Bradyrhizobium (slow-growing rhizobia) have been established. They differed considerably from other Gram-negative bacteria in regards to the backbone structure, the number of ester-linked long chain hydroxylated fatty acids, as well as the presence of a tertiary residue that consisted of at least one molecule of carboxyl-bacteriohopanediol or its 2-methyl derivative. The structural details of this type of lipid A were established using one- and two-dimensional NMR spectroscopy, chemical composition analyses, and mass spectrometry techniques (electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry and MALDI-TOF-MS). In these lipid A samples the glucosamine disaccharide characteristic for enterobacterial lipid A was replaced by a 2,3-diamino-2,3-dideoxy-d-glucopyranosyl-(GlcpN3N) disaccharide, deprived of phosphate residues, and substituted by an α-d-Manp-(1→6)-α-d-Manp disaccharide substituting C-4′ of the non-reducing (distal) GlcpN3N, and one residue of galacturonic acid (d-GalpA) α-(1→1)-linked to the reducing (proximal) amino sugar residue. Amide-linked 12:0(3-OH) and 14:0(3-OH) were identified. Some hydroxy groups of these fatty acids were further esterified by long (ω-1)-hydroxylated fatty acids comprising 26–34 carbon atoms. As confirmed by mass spectrometry techniques, these long chain fatty acids could form two or three acyloxyacyl residues. The triterpenoid derivatives were identified as 34-carboxyl-bacteriohopane-32,33-diol and 34-carboxyl-2β-methyl-bacteriohopane-32,33-diol and were covalently linked to the (ω-1)-hydroxy group of very long chain fatty acid in bradyrhizobial lipid A. Bradyrhizobium japonicum possessed lipid A species with two hopanoid residues. PMID:25371196

The role of discharge variation in scaling of drainage area and food chain length in rivers

USGS Publications Warehouse

Sabo, John L.; Finlay, Jacques C.; Kennedy, Theodore A.; Post, David M.

2010-01-01

Food chain length (FCL) is a fundamental component of food web structure. Studies in a variety of ecosystems suggest that FCL is determined by energy supply, environmental stability, and/or ecosystem size, but the nature of the relationship between environmental stability and FCL, and the mechanism linking ecosystem size to FCL, remain unclear. Here we show that FCL increases with drainage area and decreases with hydrologic variability and intermittency across 36 North American rivers. Our analysis further suggests that hydrologic variability is the mechanism underlying the correlation between ecosystem size and FCL in rivers. Ecosystem size lengthens river food chains by integrating and attenuating discharge variation through stream networks, thereby enhancing environmental stability in larger river systems.

The design and analysis of mooring system

NASA Astrophysics Data System (ADS)

Li, Yixuan

2017-05-01

In this paper, the force status and a design method of single chain mooring system for shallow sea observation network are studied. With treating the link of a chain, steel drum and steel pipe as a rigid body, the recurrence model is established by using Newton's first law and the law of Moment equilibrium theorem. Via the simplified calculation of dichotomy searching, we determine the design parameters of mooring system, such as anchor model, anchor chain length, heavy ball quality under different water flow and wind conditions. We apply MATLAB to simulate the internal steady state of the system in the fixed scheme, water depth of buoy and swimming area to meet the decision-making needs, providing an idea for the actual scheme design of mooring system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsuura, Yukihito, E-mail: matsuura@chem.nara-k.ac.jp

The tunneling magnetoresistance (TMR) of a silicon chain sandwiched between nickel electrodes was examined by using first-principles density functional theory. The relative orientation of the magnetization in a parallel-alignment (PA) configuration of two nickel electrodes enhanced the current with a bias less than 0.4 V compared with that in an antiparallel-alignment configuration. Consequently, the silicon chain-nickel electrodes yielded good TMR characteristics. In addition, there was polarized spin current in the PA configuration. The spin polarization of sulfur atoms functioning as a linking bridge between the chain and nickel electrode played an important role in the magnetic effects of the electric current.more » Moreover, the hybridization of the sulfur 3p orbital and σ-conjugated silicon 3p orbital contributed to increasing the total current.« less

The role of discharge variation in scaling of drainage area and food chain length in rivers.

PubMed

Sabo, John L; Finlay, Jacques C; Kennedy, Theodore; Post, David M

2010-11-12

Food chain length (FCL) is a fundamental component of food web structure. Studies in a variety of ecosystems suggest that FCL is determined by energy supply, environmental stability, and/or ecosystem size, but the nature of the relationship between environmental stability and FCL, and the mechanism linking ecosystem size to FCL, remain unclear. Here we show that FCL increases with drainage area and decreases with hydrologic variability and intermittency across 36 North American rivers. Our analysis further suggests that hydrologic variability is the mechanism underlying the correlation between ecosystem size and FCL in rivers. Ecosystem size lengthens river food chains by integrating and attenuating discharge variation through stream networks, thereby enhancing environmental stability in larger river systems.

Visualizing the chain-flipping mechanism in fatty-acid biosynthesis

DOE PAGES

Beld, Joris; Cang, Hu; Burkart, Michael D.

2014-10-29

The acyl carrier protein (ACP) from fatty acid synthases sequesters elongating products within its hydrophobic core, but this dynamic mechanism remains poorly understood. In this paper, we exploited solvatochromic pantetheine probes attached to ACP that fluoresce when sequestered. The addition of a catalytic partner lures the cargo out of the ACP and into the active site of the enzyme, thus enhancing fluorescence to reveal the elusive chain-flipping mechanism. This activity was confirmed by the use of a dual solvatochromic cross-linking probe and solution-phase NMR spectroscopy. Finally, the chain-flipping mechanism was visualized by single-molecule fluorescence techniques, thus demonstrating specificity between themore » Escherichia coli ACP and its ketoacyl synthase catalytic partner KASII.« less

Multiscale approach for the construction of equilibrated all-atom models of a poly(ethylene glycol)-based hydrogel

PubMed Central

Li, Xianfeng; Murthy, N. Sanjeeva; Becker, Matthew L.; Latour, Robert A.

2016-01-01

A multiscale modeling approach is presented for the efficient construction of an equilibrated all-atom model of a cross-linked poly(ethylene glycol) (PEG)-based hydrogel using the all-atom polymer consistent force field (PCFF). The final equilibrated all-atom model was built with a systematic simulation toolset consisting of three consecutive parts: (1) building a global cross-linked PEG-chain network at experimentally determined cross-link density using an on-lattice Monte Carlo method based on the bond fluctuation model, (2) recovering the local molecular structure of the network by transitioning from the lattice model to an off-lattice coarse-grained (CG) model parameterized from PCFF, followed by equilibration using high performance molecular dynamics methods, and (3) recovering the atomistic structure of the network by reverse mapping from the equilibrated CG structure, hydrating the structure with explicitly represented water, followed by final equilibration using PCFF parameterization. The developed three-stage modeling approach has application to a wide range of other complex macromolecular hydrogel systems, including the integration of peptide, protein, and/or drug molecules as side-chains within the hydrogel network for the incorporation of bioactivity for tissue engineering, regenerative medicine, and drug delivery applications. PMID:27013229

A direct comparison between gas state and atomised liquid state precursor in the deposition of functional coatings by pin corona plasma

NASA Astrophysics Data System (ADS)

Herbert, P. A. F.; Jaroszyńska-Wolińska, J.

2011-07-01

An atmospheric pressure non-thermal equilibrium pin corona plasma jet was used to deposit polymeric coatings from monomer precursor in both vapour and liquid aerosol states to allow a direct comparison of the quality and performance of the as-deposited coatings, specifically with respect to the achievement of soft plasma polymerisation (SPP) where the coating exhibits minimal fragmentation or damage to the monomer molecule while, at the same time, being highly cross-linked. A long chain perfluorocarbon molecule was introduced into the helium plasma and coatings deposited at rates of up to 50 nm/min. XPS, FTIR, contact angle and ellipsometric measurements indicated that a controlled polymerisation reaction had taken place in the case of the vapour deposited samples through the vinyl group of the monomer, with only minor fragmentation of the functional perfluoro chain. Furthermore, a high level of cross-linking was achieved and the coatings were stable to a toluene wash. In contrast, while the liquid deposition samples showed good retention of monomer molecular structure, they exhibited negligible cross-linking and were readily removed by immersion in toluene rendering them functionally useless.

Structural characterization of anti-complementary polysaccharides from the leaves of Artemisia princeps.

PubMed

Yamada, H; Otsuka, Y; Omura, S

1986-08-01

Structural characterizations of the anti-complementary acidic heteroglycans, AAF IIb-2 and IIb-3, obtained from the leaves of Artemisia princeps pamp have been studied. AAF IIb-2 consists of rhamnose, xylose, arabinose, galactose, glucose and uronic acids (glucuronic acid and galacturonic acid) in the molar ratio of 7.6:7.6:13.0:10.9:3.0:57.9, and AAF IIb-3 consists of the same sugars in the ratio of 3.9:2.6:24.7:19.7:2.6:46.5. Methylation analysis including carboxyl-reduction and also selective enzymolysis using EXO-alpha- L-arabinofuranosidase suggested that AAF IIb-3 has a main chain consisting of (1-->4)-linked galacturonic acid and (1-->2)-linked rhamnose mostly substituted at the O-4 position. AAF IIb-3 also contained arabino-3,6-galactan moiety and most of the arabinose was present as an alpha- L-furanosyl residue in the non-reducing terminals and highly branched side chains which mostly attached to the O-3 position of (1-->6)-linked galactopyranosyl residue. The basic structure of AAF IIb-2 is similar to that of AAF IIb-3, but IIb-3 has a higher arabinogalactan content than IIb-2.

OTUB1 Co-opts Lys48-Linked Ubiquitin Recognition to Suppress E2 Enzyme Function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Juang, Yu-Chi; Landry, Marie-Claude; Sanches, Mario

2012-03-26

Ubiquitylation entails the concerted action of E1, E2, and E3 enzymes. We recently reported that OTUB1, a deubiquitylase, inhibits the DNA damage response independently of its isopeptidase activity. OTUB1 does so by blocking ubiquitin transfer by UBC13, the cognate E2 enzyme for RNF168. OTUB1 also inhibits E2s of the UBE2D and UBE2E families. Here we elucidate the structural mechanism by which OTUB1 binds E2s to inhibit ubiquitin transfer. OTUB1 recognizes ubiquitin-charged E2s through contacts with both donor ubiquitin and the E2 enzyme. Surprisingly, free ubiquitin associates with the canonical distal ubiquitin-binding site on OTUB1 to promote formation of the inhibitedmore » E2 complex. Lys48 of donor ubiquitin lies near the OTUB1 catalytic site and the C terminus of free ubiquitin, a configuration that mimics the products of Lys48-linked ubiquitin chain cleavage. OTUB1 therefore co-opts Lys48-linked ubiquitin chain recognition to suppress ubiquitin conjugation and the DNA damage response.« less

In Praise of the Catenary

NASA Astrophysics Data System (ADS)

Behroozi, F.

2018-04-01

When a chain hangs loosely from its end points, it takes the familiar form known as the catenary. Power lines, clothes lines, and chain links are familiar examples of the catenary in everyday life. Nevertheless, the subject is conspicuously absent from current introductory physics and calculus courses. Even in upper-level physics and math courses, the catenary equation is usually introduced as an example of hyperbolic functions or discussed as an application of the calculus of variations. We present a new derivation of the catenary equation that is suitable for introductory physics and mathematics courses.

2,2′,5,5′-Tetra­methyl-1,1′-(hexane-1,6-di­yl)di-1H-pyrrole

PubMed Central

Santos, Ana C.; Ramos Silva, Manuela; Monsanto, Paula V.; Matos Beja, Ana; Sobral, Abilio J. F. N.

2009-01-01

The mol­ecule of the title compound, C18H28N2, composed of two 2,5-dimethyl­pyrrole groups linked by a hexane chain, lies across a crystallographic inversion centre. The mean plane of the pyrrole ring is almost perpendicular to the mean plane of the central chain, making a dihedral angle of 89.09 (8)°. The crystal structure is stabilized by inter­molecular C—H⋯π inter­actions. PMID:21582868

Radiation inactivation of ricin occurs with transfer of destructive energy across a disulfide bridge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haigler, H.T.; Woodbury, D.J.; Kempner, E.S.

1985-08-01

The ionizing radiation sensitivity of ricin, a disulfide-linked heterodimeric protein, was studied as a model to determine the ability of disulfide bonds to transmit destructive energy. The radiation-dependent loss of A chain enzymatic activity after irradiation of either intact ricin or ricin in which the interchain disulfide bond was disrupted gave target sizes corresponding to the molecular size of dimeric ricin or monomeric A chain, respectively. These results clearly show that a disulfide bond can transmit destructive energy between protein subunits.

Optical Frequency Synthesizer for Precision Spectroscopy

NASA Astrophysics Data System (ADS)

Holzwarth, R.; Udem, Th.; Hänsch, T. W.; Knight, J. C.; Wadsworth, W. J.; Russell, P. St. J.

2000-09-01

We have used the frequency comb generated by a femtosecond mode-locked laser and broadened to more than an optical octave in a photonic crystal fiber to realize a frequency chain that links a 10 MHz radio frequency reference phase-coherently in one step to the optical region. By comparison with a similar frequency chain we set an upper limit for the uncertainty of this new approach to 5.1×10-16. This opens the door for measurement and synthesis of virtually any optical frequency and is ready to revolutionize frequency metrology.

Ionochromic 4,4 '-azobispyridinium salt-incorporated polymer: synthesis and optical properties

NASA Astrophysics Data System (ADS)

Lee, Taek Seung; Ahn, Heungki; Lee, Jin Kyun; Park, Won Ho

2003-01-01

Azobispyridinium-bearing polyelectrolyte linked with flexible alkyl chain was synthesized and characterized. The polymer showed absorption changes upon addition of hydroxide anion with an isobestic point in UV-visible spectrum. It is presumed that conformational change of the azo group in the main chain is responsible for the point. Transduction of physical information (hydroxide concentration) into an optical signal from azo group was related to the ionochromic effect. Electrostatic self-assembled multilayer of the polymer with appropriate polyanion was carried out via layer-by-layer deposition.

A Novel MS-Cleavable Azo Cross-Linker for Peptide Structure Analysis by Free Radical Initiated Peptide Sequencing (FRIPS)

NASA Astrophysics Data System (ADS)

Iacobucci, Claudio; Hage, Christoph; Schäfer, Mathias; Sinz, Andrea

2017-10-01

The chemical cross-linking/mass spectrometry (MS) approach is a growing research field in structural proteomics that allows gaining insights into protein conformations. It relies on creating distance constraints between cross-linked amino acid side chains that can further be used to derive protein structures. Currently, the most urgent task for designing novel cross-linking principles is an unambiguous and automated assignment of the created cross-linked products. Here, we introduce the homobifunctional, amine-reactive, and water soluble cross-linker azobisimidoester (ABI) as a prototype of a novel class of cross-linkers. The ABI-linker possesses an innovative modular scaffold combining the benefits of collisional activation lability with open shell chemistry. This MS-cleavable cross-linker can be efficiently operated via free radical initiated peptide sequencing (FRIPS) in positive ionization mode. Our proof-of-principle study challenges the gas phase behavior of the ABI-linker for the three amino acids, lysine, leucine, and isoleucine, as well as the model peptide thymopentin. The isomeric amino acids leucine and isoleucine could be discriminated by their characteristic side chain fragments. Collisional activation experiments were conducted via positive electrospray ionization (ESI) on two Orbitrap mass spectrometers. The ABI-mediated formation of odd electron product ions in MS/MS and MS3 experiments was evaluated and compared with a previously described azo-based cross-linker. All cross-linked products were amenable to automated analysis by the MeroX software, underlining the future potential of the ABI-linker for structural proteomics studies. [Figure not available: see fulltext.

Inflammation and ER Stress Regulate Branched-Chain Amino Acid Uptake and Metabolism in Adipocytes

PubMed Central

Burrill, Joel S.; Long, Eric K.; Reilly, Brian; Deng, Yingfeng; Armitage, Ian M.; Scherer, Philipp E.

2015-01-01

Inflammation plays a critical role in the pathology of obesity-linked insulin resistance and is mechanistically linked to the effects of macrophage-derived cytokines on adipocyte energy metabolism, particularly that of the mitochondrial branched-chain amino acid (BCAA) and tricarboxylic acid (TCA) pathways. To address the role of inflammation on energy metabolism in adipocytes, we used high fat-fed C57BL/6J mice and lean controls and measured the down-regulation of genes linked to BCAA and TCA cycle metabolism selectively in visceral but not in subcutaneous adipose tissue, brown fat, liver, or muscle. Using 3T3-L1 cells, TNFα, and other proinflammatory cytokine treatments reduced the expression of the genes linked to BCAA transport and oxidation. Consistent with this, [14C]-leucine uptake and conversion to triglycerides was markedly attenuated in TNFα-treated adipocytes, whereas the conversion to protein was relatively unaffected. Because inflammatory cytokines lead to the induction of endoplasmic reticulum stress, we evaluated the effects of tunicamycin or thapsigargin treatment of 3T3-L1 cells and measured a similar down-regulation in the BCAA/TCA cycle pathway. Moreover, transgenic mice overexpressing X-box binding protein 1 in adipocytes similarly down-regulated genes of BCAA and TCA metabolism in vivo. These results indicate that inflammation and endoplasmic reticulum stress attenuate lipogenesis in visceral adipose depots by down-regulating the BCAA/TCA metabolism pathway and are consistent with a model whereby the accumulation of serum BCAA in the obese insulin-resistant state is linked to adipose inflammation. PMID:25635940

A Case Study on Engineering Failure Analysis of Link Chain

PubMed Central

Lee, Seong-Beom; Lee, Hong-Chul

2010-01-01

Objectives The objective of this study was to investigate the effect of chain installation condition on stress distribution that could eventually cause disastrous failure from sudden deformation and geometric rupture. Methods Fractographic method used for the failed chain indicates that over-stress was considered as the root cause of failure. 3D modeling and finite element analysis for the chain, used in a crane hook, were performed with a three-dimensional interactive application program, CATIA, commercial finite element analysis and computational fluid dynamic software, ANSYS. Results The results showed that the state of stress was changed depending on the initial position of the chain that was installed in the hook. Especially, the magnitude of the stress was strongly affected by the bending forces, which are 2.5 times greater (under the simulation condition currently investigated) than that from the plain tensile load. Also, it was noted that the change of load state is strongly related to the failure of parts. The chain can hold an ultimate load of about 8 tons with only the tensile load acting on it. Conclusion The conclusions of this research clearly showed that a reduction of the loss from similar incidents can be achieved when an operator properly handles the installation of the chain. PMID:22953162

Industrial metabolism of chlorine: a case study of a chlor-alkali industrial chain.

PubMed

Han, Feng; Li, Wenfeng; Yu, Fei; Cui, Zhaojie

2014-05-01

Substance flow analysis (SFA) is applied to a case study of chlorine metabolism in a chlor-alkali industrial chain. A chain-level SFA model is constructed, and eight indices are proposed to analyze and evaluate the metabolic status of elemental chlorine. The primary objectives of this study are to identify low-efficiency links in production processes and to find ways to improve the operational performance of the industrial chain. Five-year in-depth data collection and analysis revealed that system production efficiency and source efficiency continued increasing since 2008, i.e., when the chain was first formed, at average annual growth rates of 21.01 % and 1.01 %, respectively. In 2011, 64.15 % of the total chlorine input was transformed into final products. That is, as high as 98.50 % of the chlorine inputs were utilized when other by-products were counted. Chlorine loss occurred mostly in the form of chloride ions in wastewater, and the system loss rate was 0.54 %. The metabolic efficiency of chlorine in this case was high, and the chain system had minimal impact on the environment. However, from the perspectives of processing depth and economic output, the case study of a chlor-alkali industrial chain still requires expansion.

A dual chain chimeric antigen receptor (CAR) in the native antibody format for targeting immune cells towards cancer cells without the need of an scFv.

PubMed

Faitschuk, E; Nagy, V; Hombach, A A; Abken, H

2016-10-01

Adoptive cell therapy with chimeric antigen receptor (CAR)-modified T cells showed remarkable therapeutic efficacy in the treatment of leukaemia/lymphoma. However, the application to a variety of cancer entities is often constricted by the non-availability of a single chain antibody (scFv), which is usually the targeting domain in a CAR, while antibodies in the natural format are often available. To overcome the limitation, we designed a CAR that uses an antibody in its natural configuration for binding. Such CAR consists of two chains, the immunoglobulin light and heavy chain with their constant regions, whereby the heavy chain is anchored to the membrane and linked to an intracellular signalling domain for T-cell activation. The two chains form a stable heterodimer, a so-called dual chain CAR (dcCAR), and bind with high affinity and in a specific manner to their cognate antigen. By specific binding, the dcCAR activates engineered T cells for the release of pro-inflammatory cytokines and for target cell lysis. We provide evidence by three examples that the dcCAR format is universally applicable and thereby broadens the CAR cell therapy towards a larger variety of targets for which an scFv antibody is not available.

The E3 ligase HOIP specifies linear ubiquitin chain assembly through its RING-IBR-RING domain and the unique LDD extension

PubMed Central

Smit, Judith J; Monteferrario, Davide; Noordermeer, Sylvie M; van Dijk, Willem J; van der Reijden, Bert A; Sixma, Titia K

2012-01-01

Activation of the NF-κB pathway requires the formation of Met1-linked ‘linear' ubiquitin chains on NEMO, which is catalysed by the Linear Ubiquitin Chain Assembly Complex (LUBAC) E3 consisting of HOIP, HOIL-1L and Sharpin. Here, we show that both LUBAC catalytic activity and LUBAC specificity for linear ubiquitin chain formation are embedded within the RING-IBR-RING (RBR) ubiquitin ligase subunit HOIP. Linear ubiquitin chain formation by HOIP proceeds via a two-step mechanism involving both RING and HECT E3-type activities. RING1-IBR catalyses the transfer of ubiquitin from the E2 onto RING2, to transiently form a HECT-like covalent thioester intermediate. Next, the ubiquitin is transferred from HOIP onto the N-terminus of a target ubiquitin. This transfer is facilitated by a unique region in the C-terminus of HOIP that we termed ‘Linear ubiquitin chain Determining Domain' (LDD), which may coordinate the acceptor ubiquitin. Consistent with this mechanism, the RING2-LDD region was found to be important for NF-κB activation in cellular assays. These data show how HOIP combines a general RBR ubiquitin ligase mechanism with unique, LDD-dependent specificity for producing linear ubiquitin chains. PMID:22863777

Application of the network robustness index to identify critical links supporting Vermont's Bulk milk transportation.

DOT National Transportation Integrated Search

2011-08-18

The food supply chain is an interwoven network consisting of producers, processors, : manufacturers, distributors, retailers, and consumers. With the exception of direct : marketing or community-supported agriculture systems, some or all of these int...