Multiple Contact Points Research Articles

Arabidopsis Chloroplast RNA Binding Proteins CP31A and CP29A Associate with Large Transcript Pools and Confer Cold Stress Tolerance by Influencing Multiple Chloroplast RNA Processing Steps

Chloroplast RNA metabolism is mediated by a multitude of nuclear encoded factors, many of which are highly specific for individual RNA processing events. In addition, a family of chloroplast ribonucleoproteins (cpRNPs) has been suspected to regulate larger sets of chloroplast transcripts. This together with their propensity for posttranslational modifications in response to external cues suggested a potential role of cpRNPs in the signal-dependent coregulation of chloroplast genes. We show here on a transcriptome-wide scale that the Arabidopsis thaliana cpRNPs CP31A and CP29A (for 31 kD and 29 kD chloroplast protein, respectively), associate with large, overlapping sets of chloroplast transcripts. We demonstrate that both proteins are essential for resistance of chloroplast development to cold stress. They are required to guarantee transcript stability of numerous mRNAs at low temperatures and under these conditions also support specific processing steps. Fine mapping of cpRNP-RNA interactions in vivo suggests multiple points of contact between these proteins and their RNA ligands. For CP31A, we demonstrate an essential function in stabilizing sense and antisense transcripts that span the border of the small single copy region and the inverted repeat of the chloroplast genome. CP31A associates with the common 3'-terminus of these RNAs and protects them against 3'-exonucleolytic activity.

Writing in the Margins: Norse Arthurian Sagas as Palimpsests

This is a comparative study of three Old Norse translations/adaptations of French romances. The focus is on certain of the modifications made in the Norse romances as part of the process of 'acculturation,' the need to modify texts to align them with the differing assumptions of another cultural context.

Competitive Binding of the SecA ATPase and Ribosomes to the SecYEG Translocon

During co-translational membrane insertion of membrane proteins with large periplasmic domains, the bacterial SecYEG complex needs to interact both with the ribosome and the SecA ATPase. Although the binding sites for SecA and the ribosome overlap, it has been suggested that these ligands can interact simultaneously with SecYEG. We used surface plasmon resonance and fluorescence correlation spectroscopy to examine the interaction of SecA and ribosomes with the SecYEG complex present in membrane vesicles and the purified SecYEG complex present in a detergent-solubilized state or reconstituted into nanodiscs. Ribosome binding to the SecYEG complex is strongly stimulated when the ribosomes are charged with nascent chains of the monotopic membrane protein FtsQ. This binding is competed by an excess of SecA, indicating that binding of SecA and ribosomes to SecYEG is mutually exclusive.

Modeling of Tooling-Workpiece Interactions on Random Surfaces

Abrasive processes, commonly employed in manufacturing, are difficult to model because they rely on brittle particles with unknown geometry and multiple points of contact. Newly developed microreplicated abrasives allow for control of abrasive grit properties such as size, shape, and distribution. This paper proposes and validates a parametric model of abrasive machining that allows for studying the interaction of this particular tooling with randomly generated surfaces. In this work, the parameters of a probability distribution function that represents the workpiece surface are approximated by profilometry data. Monte Carlo simulation is used to account for inter- and intraspecimen variability. A geometric representation is used to mathematically represent the interaction between workpiece and tool. The results show good correlation between theoretical and actual values. This approach could be used to aid in tool geometry design as well as in process parameter optimization.

Virtual Board: A low cost Multi Touch Human Computer Interaction System

Nowadays, there are new techniques to interact remotely with a computer which by hand offer an easy management for the users and by another hand are more interactive with them. But some devices are expensive, difficult to carry out. And devices as Wiimote and Webcam are low cost, easy to carry out, but they have problems, like bad detection of signals, instability of connection with Bluetooth. Therefore, most of these devices cannot support multiple contact points; however this function is becoming more and more useful for several applications. We propose a prototype of a system to solve these deficiencies, using a Webcam and infrared active markers. The developed system offers a low cost solution for human computer interaction with a better manipulation of multiple contact points. The case study in which uses of the device and active markers to manipulate is an image viewer of satellite and aerial imagery maps.

Pediatric emergency mass critical care: The role of community preparedness in conserving critical care resources

Public health emergencies require resources at state, regional, federal, and often international levels; however, community preparedness is the crucial first step in managing these events and mitigating their consequences, particularly for children. Community preparedness can be optimized through system-wide planning that includes integrating multiple points of contact, such as the community, prehospital care, health facilities, and regional level of care assets.Citizen readiness, call centers, alternate care facilities, emergency medical services, and health emergency operations centers linked to community incident command systems should be considered as important options for delivery of population-based care. Early collaboration between pediatric clinicians and public health authorities is essential to ensure that pediatric needs are addressed in community preparedness for mass critical care events. In May 2008, the Task Force for Mass Critical Care published guidance on provision of mass critical care to adults. Acknowledging that the critical care needs of children during disasters were unaddressed by this effort, a 17-member Steering Committee, assembled by the Oak Ridge Institute for Science and Education with guidance from members of the American Academy of Pediatrics, convened in April 2009 to determine priority topic areas for pediatric emergency mass critical care recommendations.Steering Committee members established subcommittees by topic area and performed literature reviews of MEDLINE and Ovid databases. The Steering Committee produced draft outlines and convened October 6-7, 2009, in New York, NY, to review and revise each outline. Eight draft documents were subsequently developed from the revised outlines as well as through searches of MEDLINE updated through March 2010.The Pediatric Emergency Mass Critical Care Task Force, composed of 36 experts from diverse public health, medical, and disaster response fields, convened in Atlanta, GA, on March 29-30, 2010. Feedback on each manuscript was compiled and the Steering Committee revised each document to reflect expert input in addition to the most current medical literature. The Pediatric Emergency Mass Critical Care Task Force recommends active promotion of programs to ensure an informed citizenry; education of children and families in Centers for Disease Control and Prevention community mitigation strategies; emphasis on community-level preparedness empowering the public to provide self care; use of 9-1-1 telephone triage with pre-established protocols and in coordination with emergency medical services; and advocacy for healthcare coalitions and other creative operational concepts that provide guidance and protocols for care of the pediatric population.

A new method for determining wheel–rail multi-point contact

A new method for wheel–rail multi-point contact is presented in this paper. In this method, the first- and the second-order derivatives of the wheel–rail interpolation distance function and the elastic wheel–rail virtual penetration are used to determine multiple contact points. The method takes account of the yaw angle of the wheelset and allows the identification of all possible points of contact between wheel and rail surfaces with an arbitrary geometry. Static contact geometry calculations are first carried out using the developed method for both new and worn wheel profiles and with a new rail profile. The validity of the method is then verified by simulations of a coupled vehicle and track system dynamics over a small radius curve. The simulation results show that the developed method for multi-point contact is efficient and reliable enough to be implemented online for simulations of vehicle–track system dynamics.

Role of Key Aromatic Residues in the Ligand-binding Domain of α7 Nicotinic Receptors in the Agonist Action of β-Amyloid

Soluble β-amyloid (Aβ) resides in certain regions of the brain at or near picomolar concentration, rising in level during the prodromic stage of Alzheimer disease. Recently, we identified the homomeric α7 nicotinic acetylcholine receptor (α7-nAChR) as one possible functional target for picomolar Aβ. This study was aimed at addressing which residues in α7-nAChRs potentially interact with Aβ to regulate the presynaptic function of this receptor. Site-directed mutagenesis was carried out to study the key aromatic residues in the mouse α7-nAChR agonist-binding pocket. Mutations of tyrosine188 resulted in a decrease in activation of presynaptic α7-nAChRs by ACh and Aβ but with no change in response to nicotine, indicating the critical role of Tyr-188 in presynaptic regulation by Aβ. Coimmunoprecipitation additionally revealed direct binding of Aβ to α7-nAChRs and to the Tyr-188 mutant receptor. In contrast, mutations of Tyr-195 in α7-nAChR led to decreased activation by nicotine without apparent effects on ACh- or Aβ-induced responses. Agonist-induced responses of Tyr-93 mutant α7-nAChRs indicated possible interactions of nicotine and Aβ with its hydroxyl group, but there was no change in presynaptic responses after mutation of Trp-149. All of the mutants were shown to be expressed on the plasma membrane using cell surface labeling. Together, these results directly demonstrate an essential role for the aromatic residue Tyr-188 as a key component in the agonist binding domain for the activation of α7-nAChRs by Aβ.

Parametric Analysis of Transient Beam Behavior with Impact

After any terrorist attack or natural disaster, more research focuses on the dynamic response of structures under unexpected loads. Extreme loads such as explosions and earthquakes can cause enormous human and infrastructure losses. Rotating machinery can also routinely experience internal contact. Unpredicted failure may be caused by vibration-induced impact and is highly dangerous for both equipment and safety. For these reasons, the investigation of these beamlike structures under extreme loads is of importance. In this study, an Euler-Bernoulli beam with adjustable boundary conditions and variable impact is numerically studied under shock loading. Modal analysis and discrete time step methods are programmed in MATLAB to obtain linear analytical solutions. The influential parameters of structural stiffness, material modulus, contact stiffness, contact location, and damping ratio are examined. Their effects on different boundary conditions will be contrasted as well. This efficient model contributes to a better fundamental understanding of impact and will serve as a building block on which to introduce additional phenomena, such as multiple point contact, large deflection theory, and plastic material behavior.

Estimates of muscle function in human gait depend on how foot-ground contact is modelled

Computational analyses of leg-muscle function in human locomotion commonly assume that contact between the foot and the ground occurs at discrete points on the sole of the foot. Kinematic constraints acting at these contact points restrict the motion of the foot and, therefore, alter model calculations of muscle function. The aim of this study was to evaluate how predictions of muscle function obtained from musculoskeletal models are influenced by the model used to simulate ground contact. Both single- and multiple-point contact models were evaluated. Muscle function during walking and running was determined by quantifying the contributions of individual muscles to the vertical, fore-aft and mediolateral components of the ground reaction force (GRF). The results showed that two factors – the number of foot-ground contact points assumed in the model and the type of kinematic constraint enforced at each point – affect the model predictions of muscle coordination. Whereas single- and multiple-point contact models produced similar predictions of muscle function in the sagittal plane, inconsistent results were obtained in the mediolateral direction. Kinematic constraints applied in the sagittal plane altered the model predictions of muscle contributions to the vertical and fore-aft GRFs, while constraints applied in the frontal plane altered the calculations of muscle contributions to the mediolateral GRF. The results illustrate the sensitivity of calculations of muscle coordination to the model used to simulate foot-ground contact.

Droplet Impact on to a Rough Surface

The effect of surface roughness on droplet impact is considered. If a surface is sufficiently rough, then models of droplet impact need to be altered to include the possibility of many touchdowns between the fluid and the solid. The subsequent simultaneous motion of several contact points is therefore described. In particular, results are presented for the contact point motion during the impact of a sheet of water on to a periodic rough surface. A model for multiple contact point motion is also analysed for cases of deep surface roughnesses. The analysis is complemented by a direct numerical simulation using the volume of fluid method. The effect of surface roughness is to reduce the rate at which the droplet spreads. Comparisons between various roughness shapes are considered numerically and analytically. Possible applications are then discussed, especially in the context of aircraft icing.

Design of a Strategic-Tactical Stated-Choice Survey Methodology Using a Constructed Avatar

This paper presents findings from a small-sample qualitative study on people's activity travel behavior in the presence or absence of carsharing. A carsharing service provides its subscribers with short-term access to a fleet of shared cars. In previous research, subscribers have reported distinctive travel patterns, such as more car usage by subscribers than by non–car owners but less than by car owners. Reflexive techniques were used in which interviewees adapted a week of their recent activity travel behavior in response to stimuli. Findings from this study informed the design of a stated-choice survey that addressed three principal forms of complexity: (a) strategic-tactical choice situations, (b) situations in which respondents might select multiple interacting options in a single choice situation, and (c) situations in which sufficient knowledge of the individual survey respondent to tailor such a complex choice situation could not feasibly be gathered during a single interview. In the proposed design, the respondent indicates a strategic choice of which methods of travel to make available for use given a set of representative out-of-home activities. Accessibility to each activity by various means of travel is generated by using empirical distributions from Britain's National Travel Survey data sets to maximize plausibility of the information presented to respondents. An avatar (a virtual character for purposes of the survey) is constructed for each respondent on the basis of a small set of self-reported demographic characteristics. The use of multiday activity travel diaries would ideally involve multiple points of contact with each respondent at substantial cost. Therefore, an alternative method involving a single interview per respondent was sought.

Graham Mooney, Jonathan Reinarz (eds), Permeable walls: historical perspectives on hospital visiting, Wellcome Series in the History of Medicine, Clio Medica 86, Amsterdam and New York, Rodopi, 2009, pp. vi, 352, €70.00 (hardback 978-90-420-2599-8).

Graham Mooney, Jonathan Reinarz (eds), Permeable walls: historical perspectives on hospital visiting, Wellcome Series in the History of Medicine, Clio Medica 86, Amsterdam and New York, Rodopi, 2009, pp. vi, 352, €70.00 (hardback 978-90-420-2599-8).

The effect of an electronic control device on muscle injury as determined by creatine kinase enzyme

The medical literature on the effect of electronic control devices (ECD) on muscle injury is sparse. In this paper, we examine pooled data from five human studies that used creatine kinase (CK) as a marker for muscle injury. CK was measured in five separate studies involving four TASER ECDs with different exposure durations and number of circuits or contact points. Device type, exposure duration, number of circuits or contact points, and CK values at baseline and 24 h after exposure were pooled from these previous studies. Data were analyzed to determine the correlation of CK to duration of exposure, number of contact points, and distance between the probes. The pooled results contained 163 subjects. Seven were withdrawn due to incomplete data, leaving 156 subjects for analysis (median age 36, range 19-67, 93.6% male). 121 (77.6%) subjects had 2 contacts points, 10 (6.4%) had 3 contact points, 18 (11.5%) had 4 contact points, and 7 (4.5%) had 6 contact points. 81 (51.9%) subjects had a 5-s exposure, 64 (41.0%) a 10-s exposure, and, 11 (7.1%) a 30-s exposure. Median baseline CK (145 U/l, IQR 104-217, range 12-1956) did not differ between groups (P = 0.213 for number of contact points, 0.124 for duration). For the number of contacts, the median change in CK for 2 points of contact was 32 (IQR -1 to 1513, range -205 to 1821), for 3 was 1456 (IQR 634-1868, range 101-25452), for 4 was 887 (IQR 285-7481, range -1054 to 7481), and for 6 was 846 (IQR 57-1149, range -8 to 2309), (P < 0.001). For duration, the median change in CK for 5 s was 26.5 (IQR -8 to 109, range -1054 to 2309), for 10 s was 303 (IQR 34.5-1073, range -205 to 25452), and for 30 s was 47 (IQR 23-82, range -140 to 364), (P < 0.001). There was a relationship between the number of points of contact and the change in CK (P < 0.001) but not a relationship between the duration and the change in CK (P = 0.496). The median spread between the probe pairs for our pooled data was 40 cm, with a range from 18 to 70 cm (n = 76). The correlation between the change in CK and spread between the probe pairs was 0.16 at baseline (P = 0.18), and 0.24 at 24 h (P = 0.04) by Spearman's rank correlation. ECD exposure can cause a modest increase in CK. Although we cannot draw conclusions about the individual devices included in this analysis, our findings indicated that multiple contact points or exposures may result in a larger increase in CK, but the duration of the exposure does not appear to have a significant effect on CK. There is a correlation between the distance between the probes and the change in CK.

The Influence of Conductive Additives and Inter‐Particle Voids in Carbon EDLC Electrodes

AbstractThrough the interpretation of porosity and intrusion data, and correlation to the electrochemical response, this study has confirmed that are not only carbon blacks (CBs) very effective in improving the electrical connectivity of a carbon electrode coating, but they also significantly modify the porosity of the electrode coating and thereby also influence ionic diffusion. CBs are more effective conductive fillers than graphites in EDLC electrodes. The highly branched structure of CBs allows multiple electrical contact points and results in a lower electrode electronic resistance. CBs can decrease inter‐particle porosity (both volume and size) and introduce additional porosity that is characteristic of the type of carbon employed. It is observed that electrode coatings prepared from a carbon slurry have a highly macroporous structure and that electrolyte accessibility to individual activated carbon particles is unlikely to be the limiting factor to accessing capacitance. Electrochemical testing has confirmed the strong relationship between bulk electrode resistance and the accessibility of capacitance at different rates.

Abstract 2671: Structural analysis of the inhibitory mechanism of AP24534, a pan-BCR-ABL inhibitor overriding the T315I gatekeeper mutation

Abstract Although durable response in many chronic myeloid leukemia (CML) patients can be achieved by imatinib treatment, point mutations in the kinase domain of the BCR-ABL fusion protein can lead to drug resistance and relapse. Nilotinib and dasatinib, the two second generation Abl kinase inhibitors, are active against most imatinib resistant mutants with a few exceptions, particularly the T315I gatekeeper residue mutation. Using a structure-based approach we have identified AP24534, a molecule that potently inhibits the T315I mutant and all other mutants tested, thus acting as a pan-BCR-ABL inhibitor. To elucidate the basis for this unique profile of AP24534, we have used a combination of X-ray crystallographic and structure-activity relationship analysis on AP24534 and its analogs. The crystal structure of the T315I mutant Abl in complex with the inhibitor clearly demonstrates that AP24534 binds to Abl in a DFG-out binding mode with the ethynyl chemical moiety skirting the mutated gate-keeper residue avoiding steric clashes. The X-ray co-structures of both the wild type and the T315I mutant Abl, in conjunction with the SAR analysis, further reveal that AP24534 retains potency against the T315I and other imatinib-resistant ABL mutants through optimized multiple points of contact, balancing and distributing the overall binding affinity so that mutation-based disruption of one facet of the binding network results in only a slight reduction in binding affinity. Our structural analysis enables us to predict and rationalize the different degree of sensitivity of ABL point mutants to AP24534, and to understand how AP24534 can completely abrogate resistance in cell-based mutagenesis screens at relatively low concentrations. AP24534 is currently being investigated in a Phase I clinical trial in patients with refractory and resistant CML and other hematological malignancies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2671.

An analytical approach for selection of a logistics provider

PurposeCAPARO India Ltd., a leading player in the automotive components industry in India, has multiple logistics providers for export‐import logistics at its five manufacturing locations in north India. Dealing with multiple logistics provider restricts negotiation power, service commitments, customer satisfaction and leads to higher transportation cost and time delays due to multiple points of contact. The purpose of this paper is to document CAPARO's aim of selecting one common logistics provider for all their units in north India for export‐import logistics, warehousing, packaging and value added services in order to minimise all the above stated problems.Design/methodology/approachThis paper, in the form of case study, provides a structured decision‐making model for selection of the most suitable logistics provider using the analytic hierarchy process (AHP). With this technique, several criteria like freight charges, inland charges, schedule flexibility, warehousing capacity, track and trace system, port presence and custom clearance are considered that make it possible to select a suitable logistics provider.FindingsThe case example establishes that AHP can be effectively used to analyse the logistics provider selection, which is based on real data.Research limitations/implicationsThe case extends the scope for future researchers to enhance the criteria for selection of any logistics provider.Practical implicationsThe paper provides practitioners with a systematic analysis needed to make this important decision.Originality/valueThe paper is based on real data and information.

Contrasting Municipal Responses to the Provision of Birth Control Services in Halifax and Exeter before 1948

Research exploring the development of the birth control movement in Britain continues to reveal new insights. Local case studies highlight the contentious nature of birth control debates and the significant obstacles that had to be overcome before services could be provided. Moving away from a focus on the activities of birth control campaigners and organisations, such as the Family Planning Association, this paper highlights other local actors in the statutory and voluntary sectors to map why clinics emerged when and where they did. The contrasting examples, provided by Exeter and Halifax, demonstrate the importance of multiple points of contact between local authorities and supporters and opponents of birth control. They also suggest that the attitude of local medical and political elites is not sufficient to explain the success or failure of any clinic.

The substrate as a skeleton: ground reaction forces from a soft-bodied legged animal

The measurement of forces generated during locomotion is essential for the development of accurate mechanical models of animal movements. However, animals that lack a stiff skeleton tend to dissipate locomotor forces in large tissue deformation and most have complex or poorly defined substrate contacts. Under these conditions, measuring propulsive and supportive forces is very difficult. One group that is an exception to this problem is lepidopteran larvae which, despite lacking a rigid skeleton, have well-developed limbs (the prolegs) that can be used for climbing in complex branched structures and on a variety of surfaces. Caterpillars therefore are excellent for examining the relationship between soft body deformation and substrate reaction forces during locomotion. In this study, we devised a method to measure the ground reaction forces (GRFs) at multiple contact points during crawling by the tobacco hornworm (Manduca sexta). Most abdominal prolegs bear similar body weight during their stance phase. Interestingly, forward reaction forces did not come from pushing off the substrate. Instead, most positive reaction forces came from anterior abdominal prolegs loaded in tension while posterior legs produced drag in most instances. The counteracting GRFs effectively stretch the animal axially during the second stage of a crawl cycle. These findings help in understanding how a terrestrial soft-bodied animal can interact with its substrate to control deformation without hydraulic actuation. The results also provide insights into the behavioral and mechanistic constraints leading to the evolution of diverse proleg arrangements in different species of caterpillar.

Architecture of a nascent viral fusion pore

Enveloped viruses use specialized protein machinery to fuse the viral membrane with that of the host cell during cell invasion. In influenza virus, hundreds of copies of the haemagglutinin (HA) fusion glycoprotein project from the virus surface. Despite intensive study of HA and its fusion activity, the protein's modus operandi in manipulating viral and target membranes to catalyse their fusion is poorly understood. Here, the three-dimensional architecture of influenza virus–liposome complexes at pH 5.5 was investigated by electron cryo-tomography. Tomographic reconstructions show that early stages of membrane remodeling take place in a target membrane-centric manner, progressing from punctate dimples, to the formation of a pinched liposomal funnel that may impinge on the apparently unperturbed viral envelope. The results suggest that the M1 matrix layer serves as an endoskeleton for the virus and a foundation for HA during membrane fusion. Fluorescence spectroscopy monitoring fusion between liposomes and virions shows that leakage of liposome contents takes place more rapidly than lipid mixing at pH 5.5. The relation of ‘leaky' fusion to the observed prefusion structures is discussed.