Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Bundles

  • bachmann bundle
  • carbon nanotube bundle
  • care bundle
  • collagen bundle
  • fiber bundle
  • fibre bundle
  • fibril bundle
  • filament bundle
  • forebrain bundle
  • four-helix bundle
  • helical bundle
  • helix bundle
  • medial forebrain bundle
  • muscle bundle
  • nanotube bundle
  • nerve bundle
  • neurite bundle
  • neurovascular bundle
  • smooth muscle bundle
  • three-helix bundle
  • tube bundle
  • vascular bundle

  • Terms modified by Bundles

  • bundle branch
  • bundle branch block
  • bundle branch block pattern
  • bundle protein
  • bundle sheath cell
  • bundle structure

  • Selected Abstracts

    Successes and Lessons Learned Implementing the Sepsis Bundle

    Wayne E. Soo Hoo
    Abstract: Sepsis is well described in the literature as a leading cause of possibly preventable death in the United States. Analysis of baseline data indicated capacity to reduce mortality, significant variation in clinical practice patterns and opportunities for reducing cost per case. Following an enterprise-wide challenge to save lives, a multidisciplinary, facility-based team was organized to improve sepsis care. Systematic improvements in recognizing sepsis and standardizing care resulted in a dramatic reduction in mortality and a significant reduction in direct variable cost. [source]

    Demonstration of Electrical and Anatomic Connections Between Marshall Bundles and Left Atrium in Dogs: Implications on the Generation of P Waves on Surface Electrocardiogram

    Marshall Bundle and P Wave.Introduction: The muscle bundles within the ligament of Marshall (LOM) are electrically active. The importance of these muscle bundles (Marshall bundle [MB]) to atrial activation and the generation of the ECG P wave is unclear. Methods and Results: We used optical mapping techniques to study epicardial activation patterns in isolated perfused left atrium in four dogs. In another seven dogs, P waves were studied before and after in vivo radiofrequency (RF) ablation of the connection between coronary sinus (CS) and the LOM. Computerized mapping was performed before and after RF ablation. Optical mapping studies showed that CS pacing resulted in broad wavefronts propagating from the middle and distal LOM directly to the adjacent left atrium (LA). Serial sections showed direct connection between MB and LA near the orifice of the left superior pulmonary vein in two dogs. In vivo studies showed that MB potentials were recorded in three dogs. After ablation, the duration of P waves remained unchanged. In the other four dogs, MB potentials were not recorded. Computerized mapping showed that LA wavefronts propagated to the MB region via LA-MB connection and then excited the CS. After ablation, the activation of CS muscle sleeves is delayed, and P wave duration increased from 65.3 ± 14.9 msec to 70.5 ± 17.2 msec (P = 0.025). Conclusion: In about half of the normal dogs, MB provides an electrical conduit between LA free wall and CS. Severing MB alters the atrial activation and lengthens the P wave. MB contributes to generation of the P wave on surface ECG. [source]

    A systematic review of the efficacy of non-pharmacological treatments for depression on glycaemic control in type 2 diabetics

    Mei-Yeh Wang
    Aims and objectives., This paper reported a systematic review of three randomised controlled clinical trials evaluating the efficacy of non-pharmacological treatment of depression on glycaemic control in individuals with type 2 diabetes. Background., Depression is associated with poor adherence to self-care regimen in individuals with diabetes. A significant relationship between depression and poor glycaemic control has also been suggested. Hence, the management of depression becomes an important aspect of diabetes care. Design., Systematic review. Methods., Cochrane library, Pubmed, MEDLINE, EBM review, ProQuest Medical Bundle and SCOPUS databases were searched using the following medical subject headings or key words , depression, mood disorder, depressive symptoms, diabetes mellitus, glycaemic control, glycated haemoglobin, glucose, psychological therapy, psychotherapy, non-pharmacological therapy and cognitive behaviour therapy. The publication date was limited from 1996,2007. Studies were selected if they used a randomised controlled trial design, were written in English, used non-pharmacological treatments for treating depression, included individuals with type 2 diabetes mellitus as participants and included depressive symptoms and glycaemic control (determined by haemoglobin A1C) as outcomes. Results., Non-pharmacological treatments of depression reduce depressive symptoms in diabetic patients. However, cognitive behaviour therapy did not improve glycaemic control. The treatment effect sizes for glycaemic control in the two collaborative-care programmes were also small. Conclusions., The available evidence indicated that non-pharmacological treatment of depression had limited effect on glycaemic control in individuals with type 2 diabetes. Relevance to clinical practice., The depression-focused interventions might not achieve optimal diabetes-related outcomes. The beneficial effect of psychological treatment for glycaemic control may be strengthened by employing treatments tailored to each individual's diabetes self-care needs in addition to depression management. [source]

    Idealized design of perinatal care

    Faith McLellan PhD
    Idealized Design of Perinatal Care is an innovation project based on the principles of reliability science and the Institute for Healthcare Improvement's (IHI's) model for applying these principles to improve care.1 The project builds upon similar processes developed for other clinical arenas in three previous IHI Idealized Design projects. The Idealized Design model focuses on comprehensive redesign to enable a care system to perform substantially better in the future than the best it can do at present. The goal of Idealized Design of Perinatal Care is to achieve a new level of safer, more effective care and to minimize some of the risks identified in medical malpractice cases. The model described in this white paper, Idealized Design of Perinatal Care, represents the Institute for Healthcare Improvement's best current assessment of the components of the safest and most reliable system of perinatal care. The four key components of the model are: 1) the development of reliable clinical processes to manage labor and delivery; 2) the use of principles that improve safety (i.e., preventing, detecting, and mitigating errors); 3) the establishment of prepared and activated care teams that communicate effectively with each other and with mothers and families; and 4) a focus on mother and family as the locus of control during labor and delivery. Reviews of perinatal care have consistently pointed to failures of communication among the care team and documentation of care as common factors in adverse events that occur in labor and delivery. They are also prime factors leading to malpractice claims.2 Two perinatal care "bundles", a group of evidence-based interventions related to a disease or care process that, when executed together, result in better outcomes than when implemented individually , are being tested in this Idealized Design project: the Elective Induction Bundle and the Augmentation Bundle. Experience from the use of bundles in other clinical areas, such as care of the ventilated patient, has shown that reliably applying these evidence-based interventions can dramatically improve outcomes.3 The assumption of this innovation work is that the use of bundles in the delivery of perinatal care will have a similar effect. The authors acknowledge that other organizations have also been working on improving perinatal care through the use of simulation training and teamwork and communication training. IHI's model includes elements of these methods. The Idealized Design of Perinatal Care project has two phases. Sixteen perinatal units from hospitals around the US participated in Phase I, from February to August 2005. The goals of Phase I were identifying changes that would make the most impact on improving perinatal care, selecting elements for each of the bundles, learning how to apply IHI's reliability model to improve processes, and improving the culture within a perinatal unit. This white paper provides detail about the Idealized Design process and examines some of the initial work completed by teams. Phase II, which began in September 2005, expands on this work. This phase focuses particularly on managing second stage labor, including common interpretation of fetal heart monitoring, developing a reliable tool to identify harm, and ensuring that patient preferences are known and honored. [source]

    Exact Location of the Branching Bundle in the Living Heart

    Aims: The His bundle electrogram is believed to reflect the exact location of the His bundle. However, the distinction between distal His bundle potential and proximal right bundle branch potential is challenging. The aim of this study was to pinpoint the location of the branching point of the His bundle, and to compare that site with the site of recording of the largest His bundle electrogram (LH) during sinus rhythm. Methods: We hypothesized that the site of earliest His activation (EH) during retrograde conduction via the left bundle branch is the branching point. We studied 15 nonconsecutive patients (mean age = 40 ± 22 years; eight men). We performed a programmed stimulation from right ventricular apex until retrograde right bundle branch block appeared. At that point we measured (1) the distance between antegrade LH site and retrograde EH site and (2) the atrial-to-ventricular amplitude ratio (A/V ratio) at both sites. Results: EH was recorded at the proximal electrode of the His bundle catheter in all patients. Mean distance between EH and LH was 9.8 ± 2.5 mm. The mean A/V ratios at the EH site and the LH site were 1.01 ± 0.42 and 0.08 ± 0.06, respectively. Discussion: This study showed that the EH site is located approximately 10-mm proximal to the LH site. The mean A/V ratio at the EH site during sinus rhythm is approximately 1.0. These observations suggest that the majority of His potentials reflect proximal right bundle activation. Before delivering radiofrequency energy in the para-Hisian area, attention should be paid to the presence of a His potential and to the A/V ratio, rather to the amplitude of the His electrogram. [source]

    Validation of Criteria for Selective His Bundle and Para-Hisian Permanent Pacing

    F. CANTÙ M.D.
    Background: His Bundle (HB) pacing is a valid alternative to right ventricular pacing for patients with preserved His-ventricle conduction who are candidates for permanent stimulation. Permanent pacing in the HB area enables Selective HB pacing (SHBP) or para-Hisian pacing (PHP) to be achieved. The aim of our study was to draw up a set of easy criteria to differentiate and validate the two kinds of stimulations according to the pacing output and the ECG/EKG signals. Methods and Results: From February to July 2005, 17 patients eligible for a pacemaker (PM) procedure underwent implantation with the Medtronic SelectSecure® lead (Medtronic, Minneapolis, MN, USA) screwed into the HB area.SHBP was defined when the intrinsic QRS was equal, in both duration and morphology, to the paced QRS, the His-Ventricular (H-V) interval was equal to Pace-Ventricular interval (Vp-V) and, at low output, only the HB was captured, while increasing the output resulted in both the HB and right ventricular (RV) being captured (widening of QRS at high output). Conversely, PHP was defined when the intrinsic QRS differed from the paced one, either in morphology or in duration and, at high output, both the RV and HB were captured (non-SHBP), while decreasing the output resulted in losing HB capture (widening of QRS at low output). According to these criteria, SHBP was achieved in 11 patients, while in the remaining 6, PHP was obtained. No adverse events were reported. Conclusions: The above criteria enabled SHBP and PHP to be validated easily and clearly. A longer follow-up will be needed in order to ascertain whether the clinical outcome of these two approaches differs. [source]

    The Utility of a Quality Improvement Bundle in Bridging the Gap between Research and Standard Care in the Management of Severe Sepsis and Septic Shock in the Emergency Department

    H. Bryant Nguyen MD
    The research in the management of severe sepsis and septic shock has resulted in a number of therapeutic strategies with significant survival benefits. These results also emphasize the primary importance of early hemodynamic resuscitation, or early goal-directed therapy (EGDT), and place the emergency physician in the center of the multidisciplinary team caring for patients with this disease. However, in a busy emergency department, the translation of research into clinical practice is far from ideal. While the benefits are significant, the successful implementation of EGDT is filled with challenges and obstacles. In this article, we will discuss the steps taken at our institution to create, implement, measure, and improve on a six-hour severe sepsis and septic shock treatment bundle incorporating EGDT in the emergency department setting, resulting in significant mortality benefit. [source]

    A Mechanically Interlocked Bundle

    Jovica D. Badji
    Abstract The prototype of an artificial molecular machine consisting of a trisammonium tricationic component interlocked with a tris(crown ether) component to form a molecular bundle with averaged C3v symmetry has been designed and synthesized. The system is based on noncovalent interactions, which include 1) N+H,,,O hydrogen bonds; 2) CH,,,O interactions between the CH2NH2+CH2 protons on three dibenzylammonium-ion-containing arms, which are attached symmetrically to a benzenoid core, and three dibenzo[24]crown-8 macrorings fused onto a triphenylene core; and 3) ,,,,, stacking interactions between the aromatic cores. The template-directed synthesis of the mechanically interlocked, triply threaded bundle involves post- assembly covalent modification, that is, the efficient conversion of three azide functions at the ends of the arms of the bound and threaded trication into bulky triazole stoppers, after 1,3-dipolar cycloaddition with di- tert -butylacetylenedicarboxylate to the extremely strong 1:1 adduct that is formed in dichloromethane/acetonitrile (3:2), on account of a cluster effect associated with the paucivalent adduct. Evidence for the averaged C3v symmetry of the molecular bundle comes from absorption and luminescence data, as well as from electrochemical experiments, 1H NMR spectroscopy, and mass spectrometry. The photophysical properties of the mechanically interlocked bundle are very similar to those of the superbundle that precedes the formation of the bundle in the process of supramolecular assistance to covalent synthesis. Although weak non-nucleophilic bases (e.g., nBu3N and iPr2NEt) fail to deprotonate the bundle, the strong tBuOK does, as indicated by both luminescence and 1H NMR spectroscopy. While deprotonation undoubtedly loosens up the interlocked structure of the molecular bundle by replacing relatively strong N+H,,,O hydrogen bonds by much weaker NH,,,O ones, the ,,,,, stacking interactions ensure that any structural changes are inconsequential, particularly when the temperature of the solution of the neutral molecular bundle in dichloromethane is cooled down to considerably below room temperature. [source]

    Illustrative White Matter Fiber Bundles

    Ron Otten
    Abstract Diffusion Tensor Imaging (DTI) has made feasible the visualization of the fibrous structure of the brain white matter. In the last decades, several fiber-tracking methods have been developed to reconstruct the fiber tracts from DTI data. Usually these fiber tracts are shown individually based on some selection criteria like region of interest. However, if the white matter as a whole is being visualized clutter is generated by directly rendering the individual fiber tracts. Often users are actually interested in fiber bundles, anatomically meaningful entities that abstract from the fibers they contain. Several clustering techniques have been developed that try to group the fiber tracts in fiber bundles. However, even if clustering succeeds, the complex nature of white matter still makes it difficult to investigate. In this paper, we propose the use of illustration techniques to ease the exploration of white matter clusters. We create a technique to visualize an individual cluster as a whole. The amount of fibers visualized for the cluster is reduced to just a few hint lines, and silhouette and contours are used to improve the definition of the cluster borders. Multiple clusters can be easily visualized by a combination of the single cluster visualizations. Focus+context concepts are used to extend the multiple-cluster renderings. Exploded views ease the exploration of the focus cluster while keeping the context clusters in an abstract form. Real-time results are achieved by the GPU implementation of the presented techniques. [source]

    Large Apical Muscular Ventricular Septal Defect: Asymptomatic due to Anomalous Muscle Bundles in the Right Ventricle

    Anant Khositseth MD
    ABSTRACT This case report demonstrated an apical muscular ventricular septal defect (VSD) that was a large defect but behaved like a small defect because of the restrictive flow across the anomalous muscle bundles in the right ventricular (RV) apex. The anomalous muscle bundles separated the RV sinus into two parts: the RV apex connecting with the left ventricle through the apical muscular VSD on one side, and the rest of the RV sinus connecting with RV inflow and RV outflow on the other side. These findings explained why the 11-year-old girl in this study remained asymptomatic without evidence of volume load. Thus far, it was not necessary to close her defect because of the hemodynamic insignificance. [source]

    Strikingly fast microtubule sliding in bundles formed by Chlamydomonas axonemal dynein,

    CYTOSKELETON, Issue 6 2010
    Susumu Aoyama
    Abstract Chlamydomonas axonemal extracts containing outer-arm dynein bundle microtubules when added in the absence of ATP. The bundles dissociate after addition of ATP (Haimo et al., Proc Natl Acad Sci USA 76:5759,5768, 1979). In the present study, we investigated the ATP-induced bundle dissociation process using caged ATP. Application of ,0.5 mM ATP induced microtubule sliding at ,30 ,m·s,1, which was 1.5 times faster than the microtubule sliding observed in protease-treated axonemes and five times faster than microtubule gliding on glass surfaces coated with outer-arm dynein. Bundles formed by mutant dynein molecules that lack one of the three heavy chains (HCs) displayed similar high-speed intermicrotubule sliding. These results suggest that Chlamydomonas outer-arm dynein molecules, when aligned, can translocate microtubules at high speed and that the high-speed sliding under load-free conditions does not require the complete set of the three HCs. It is likely that each of the three HCs has the ability to produce high-speed sliding, which should be an important property for their cooperation. © 2010 Wiley-Liss, Inc. [source]

    A Waveguide-Like Effect Observed in Multiwalled Carbon Nanotube Bundles

    Shengyong Xu
    Abstract The delay time of nanosecond electromagnetic pulses is measured in multiwalled carbon nanotube (MWCNT) bundles and copper wires, with a length of up to 3,cm, as compared with that in standard coaxial cables of the same lengths. Under certain configurations, when the Cu core of a coaxial cable is replaced with a MWCNT bundle of the same length, the measured delay time of a pulsed signal is shortened. The difference between the delay time measured for a device with a Cu core and that of a device with a MWCNT bundle of the same length increases with the length of the samples. The results imply that, compared with Cu wires, MWCNT bundles may be more efficient in guiding the transmission of high-frequency signals along their longitudinal axis, showing a waveguide-like effect. [source]

    In situ Mechanical Testing Reveals Periodic Buckle Nucleation and Propagation in Carbon Nanotube Bundles

    Shelby B. Hutchens
    Abstract Uniaxial compression studies are performed on 50-µm-diameter bundles of nominally vertical, intertwined carbon nanotubes grown via chemical vapor deposition from a photolithographically defined catalyst. The inhomogeneous microstructure is examined, demonstrating density and tube orientation gradients, believed to play a role in the unique periodic buckling deformation mechanism. Through in situ uniaxial compression experiments it is discovered that the characteristic bottom-to-top sequential buckling proceeds by first nucleating on the bundle surface and subsequently propagating laterally through the bundle, gradually collapsing the entire structure. The effects of strain rate are explored, and storage and loss stiffnesses are analyzed in the context of energy dissipation. [source]

    Large-Scale Synthesis of Long Crystalline Cu2-xSe Nanowire Bundles by Water-Evaporation-Induced Self-Assembly and Their Application in Gas Sensing

    Jun Xu
    Abstract By a facile water evaporation process without adding any directing agent, Cu2-xSe nanowire bundles with diameters of 100,300,nm and lengths up to hundreds of micrometers, which comprise crystalline nanowires with diameters of 5,8,nm, are obtained. Experiments reveal the initial formation/stacking of CuSe nanoplates and the subsequent transformation to the Cu2-xSe nanowire bundles. A water-evaporation-induced self-assembly (WEISA) mechanism is proposed, which highlights the driving force of evaporation in promoting the nanoplate stacking, CuSe-to-Cu2-xSe transformation and the growth/bundling of the Cu2-xSe nanowires. The simplicity, benignancy, scalability, and high-yield of the synthesis of this important nanowire material herald its numerous applications. As one example, the use of the Cu2-xSe nanowire bundles as a photoluminescence-type sensor of humidity is demonstrated, which shows good sensitivity, ideal linearity, quick response/recovery and long lifetime in a very wide humidity range at room temperature. [source]

    Electronic journal provision in a health-care library: insights from a consultation with NHS workers

    Sarah E. Crudge
    Objective:, This study determines the current awareness journal reading requirements of the users of Stockport National Health Service (NHS) Trust's library. The overlap between requirements and the provision of the NHS Core Content resources, four major electronic journal bundles, and the holdings of North West health libraries is also investigated. Methods:, A survey of both hospital and Primary Care Trust staff was conducted, and respondents were required to provide a list of their favourite journal titles. Each requested title was assigned a subject code, and the impact factor was noted. Results:, From 135 survey responses, 217 journal titles were identified and 33 category codes were utilized. There was little overlap between the request list and the NHS Core Content titles, but substantial correspondence existed between the request list and the print holdings of North West health libraries. Conclusions:, Current awareness journal reading requirements will not be met by the Core Content provision alone. Bundles of titles offer value-for-money solutions, but may be at the expense of popular titles. Furthermore, the success of regional document supply schemes may be compromised if large numbers of health-care libraries replace print holdings with similar electronic journal bundles. [source]

    Demonstration of Electrical and Anatomic Connections Between Marshall Bundles and Left Atrium in Dogs: Implications on the Generation of P Waves on Surface Electrocardiogram

    Marshall Bundle and P Wave.Introduction: The muscle bundles within the ligament of Marshall (LOM) are electrically active. The importance of these muscle bundles (Marshall bundle [MB]) to atrial activation and the generation of the ECG P wave is unclear. Methods and Results: We used optical mapping techniques to study epicardial activation patterns in isolated perfused left atrium in four dogs. In another seven dogs, P waves were studied before and after in vivo radiofrequency (RF) ablation of the connection between coronary sinus (CS) and the LOM. Computerized mapping was performed before and after RF ablation. Optical mapping studies showed that CS pacing resulted in broad wavefronts propagating from the middle and distal LOM directly to the adjacent left atrium (LA). Serial sections showed direct connection between MB and LA near the orifice of the left superior pulmonary vein in two dogs. In vivo studies showed that MB potentials were recorded in three dogs. After ablation, the duration of P waves remained unchanged. In the other four dogs, MB potentials were not recorded. Computerized mapping showed that LA wavefronts propagated to the MB region via LA-MB connection and then excited the CS. After ablation, the activation of CS muscle sleeves is delayed, and P wave duration increased from 65.3 ± 14.9 msec to 70.5 ± 17.2 msec (P = 0.025). Conclusion: In about half of the normal dogs, MB provides an electrical conduit between LA free wall and CS. Severing MB alters the atrial activation and lengthens the P wave. MB contributes to generation of the P wave on surface ECG. [source]

    Ultrastructural study of the precursor to fungiform papillae prior to the arrival of sensory nerves in the fetal rat

    Shin-ichi Iwasaki
    Abstract The structure of precursors to fungiform papillae without taste buds, prior to the arrival of sensory nerve fibers at the papillae, was examined in the fetal rat on embryonic day 13 (E13) and 16 (E16) by light and transmission electron microscopy in an attempt to clarify the mechanism of morphogenesis of these papillae. At E13, a row of rudiments of fungiform papillae was arranged along both sides of the median sulcus of the lingual dorsal surface, and each row consisted of about 10 rudiments. There was no apparent direct contact between papillae rudiments and sensory nerves at this time. Bilaterally towards the lateral side of the tongue, adjacent to these first rudiments of fungiform papillae, a series of cord-like invaginations of the dorsal epithelium of the tongue into the underlying connective tissue, representing additional papillary primordia parallel to the first row, was observed. The basal end of each invagination was enlarged as a round bulge, indented at its tip by a mound of fibroblasts protruding into the bulge. At E16 there was still no apparent direct contact between rudiments of fungiform papillae and sensory nerves. Each rudiment apically contained a spherical core of aggregating cells, which consisted of a dense assembly of large, oval cells unlike those in other areas of the lingual dorsal epithelium. The differentiation of these aggregated cells was unclear. The basal lamina was clearly recognizable between the epithelium of the rudiment of fungiform papillae and the underlying connective tissue. Spherical structures, which appeared to be sections of the cord-like invaginations of the lingual epithelium that appeared on E13, were observed within the connective tissue separated from the dorsal lingual epithelium. Transverse sections of such structures revealed four concentric layers of cells: a central core, an inner shell, an outer shell, and a layer of large cells. Bundles of fibers were arranged in the central core, and the diameters of bundles varied somewhat depending on the depth of the primordia within the connective tissue and their distance from the median sulcus. Ultrastructural features of cells in the outer shell differed significantly in rudiments close to the lingual epithelium as compared to those in deeper areas of connective tissue. Around the outer shell there was a large-cell layer consisting of one to three layers of radially elongated, oval cells that contained many variously sized, electron-dense, round granules. Large numbers of fibroblasts formed dense aggregates around each spherical rudiment, and were separated by the basal lamina from the large-cell epithelial layer. Progressing from deep-lying levels of the rudiments of the papillae to levels close to the lingual surface epithelium, the central core, inner shell, and outer shell gradually disappeared from the invaginated papillary cords. J. Morphol. 250:225,235, 2001. © 2001 Wiley-Liss, Inc. [source]

    Flexible work bundles and organizational competitiveness: a cross-national study of the European work context

    Eleni T. Stavrou
    The present study explores the categorization of flexible work arrangements (FWAs) into bundles and their connection to organizational competitiveness in the European Union. The measures of competitiveness were performance, turnover, and absenteeism. Four moderators were used in the study, organization sector, industry sector, organization size, and organizational women-supportiveness. The analyses revealed four FWA Bundles, namely Non-Standard Work Patterns, Work Away from the Office, Non-Standard Work Hours and Work Outsourced. Non-Standard Work Patterns were found to be related to decreased turnover (in the private sector), while Work Away from the Office was related to improved performance and reduced absenteeism. Non-Standard Work Hours and Work Outsourced (within the public sector) were positively related to turnover, suggesting that these types are possibly not being used as true flexibility arrangements. Finally, post-hoc analysis revealed that Non-Standard Work Hours was related to increased performance only among Swedish organizations. Implications for management and future research are discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Vibrational properties of single walled carbon nanotubes under pressure from Raman scattering experiments and molecular dynamics simulations

    In-Hwan Choi
    Abstract We have investigated theoretically and experimentally the pressure dependent structural and vibrational properties of single-walled carbon nanotubes (SWNT). Bundles of SWNTs are studied inside a diamond anvil high pressure cell with micro-Raman scattering. The tube diameter and size distribution are determined from the radial breathing modes (RBM) of the tubes. The pressure coefficient and linewidth of one of the high frequency C,C bond stretching modes was found to change suddenly at ,3 GPa which is well below the structural transformation pressure (Pc) for the tubes in our sample. Molecular dynamics simulations were used to calculate the vibrational density of states of SWNTs as a function of pressure. Our simulations suggest that the experimental results can be explained by a softening of a low-frequency optical mode of the SWNTs , the "squashing" mode , and the dynamical effect of this softening on other phonon modes. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    The Surviving Sepsis Campaign and Sepsis Care Bundles: substance or sophistry?

    ANAESTHESIA, Issue 4 2006
    S. J. Fletcher
    No abstract is available for this article. [source]

    Bundles of Auer rods in blast cells and mature neutrophils in a non-promyelocytic acute myeloblastic leukaemia

    Estelle Guérin
    No abstract is available for this article. [source]

    RNA Grooves Can Accommodate Disulfide-Bridged Bundles of ,-Helical Peptides

    CHEMBIOCHEM, Issue 6 2010
    Soonsil Hyun Dr.
    Feelin' groovy: A strategy for chemical stapling increases structural as well as chemical stability of helical peptides. Using an amphiphilic peptide with Leu/Lys, two Leu residues were replaced by Cys. Helical bundle peptides were generated by oxidative disulfide bond formation. One of these has a Kd as low as 21 pM against hairpin targets. This observation demonstrates that the groove in small hairpin RNA has sufficient room to contain a helical bundle peptide. [source]

    Behavior of Ni-Doped MgMoO4 Single-Phase Catalysts for Synthesis of Multiwalled Carbon Nanotube Bundles

    Y. Li
    Abstract A significant effect is found when various ratios of CH4/H2 and CH4/N2 are used for the synthesis of multiwalled carbon nanotube (MWNT) bundles on nickel-doped MgMoO4 (Ni/Mo/MgO) as a catalyst. The absorption of hydrogen makes the nickel,molybdenum nanoparticles highly dispersed on the porous MgO, and the synergism of nickel,molybdenum has the effect that sufficient carbon atoms are rapidly dissolved in the molten nickel-molybdenum nanoparticles, leading to a high yield of MWNTs. The phase transformations of the catalysts and the formation mechanism of the MWNT bundles on Ni/Mo/MgO catalyst are also presented. [source]

    The Use of Optical Fiber Bundles Combined with Electrochemistry for Chemical Imaging

    CHEMPHYSCHEM, Issue 2 2003
    Sabine Szunerits Dr.
    Abstract The present Review describes the progress made in using imaging optical fiber bundles for fluorescence and electrochemical-initiated chemiluminescence imaging. A novel optoelectrochemical micro-ring array has been fabricated and demonstrated for concurrent electrochemical and optical measurements. The device comprises optical fibers coated with gold via electroless gold deposition and assembled in a random array format. The design yielded an array of approximately 200 micro-ring electrodes, where interdiffusional problems were minimized. The inner diameter of the ring electrode is fixed by the diameter of the individual optical fibers (25 ,m), while the outer radius is determined by the thickness of the deposited gold. While all the fibers are optically addressable, they are not all electrochemically addressable. The resolution of this device is in the tens of micrometers range, determined by the diameter of the optical fiber (25 ,m) and by the spacing between each electrically connected fiber. For the purpose of having well-behaved microelectrode characteristics, this spacing was designed to be larger than 60 ,m. The array was characterized using ferrocyanide in aqueous solution as a model electroactive species to demonstrate that this microelectrode array format exhibits steady-state currents at short response times. This device has potential application to be used as an optoelectronic sensor, especially for the electrolytic generation and transmission of electrochemiluminescence, and was used to demonstrate that electrochemically generated luminescent products can be detected with the fiber assembly. [source]

    Verapamil-sensitive Ventricular Tachycardia in an Infant

    Christopher Snyder MD
    ABSTRACT Patients., We report on a 6-month-old patient with a right bundle, superior axis tachycardia at 197 beats per minute. The tachycardia was unresponsive to adenosine, propranolol, flecainide, or amiodarone, or synchronized cardioversion. Overdrive atrial pacing terminated the tachycardia and since initiating verapamil, no recurrences of his tachycardia have occurred. Conclusions., If an infant presents with a right bundle, superior axis ventricular tachycardia unresponsive to multiple antiarrhythmic medications and synchronized cardioversion, but responsive to overdrive atrial pacing, one must consider verapamil-sensitive ventricular tachycardia and initiate appropriate therapy. [source]

    Dynamic compartmentalization of protein tyrosine phosphatase receptor Q at the proximal end of stereocilia: Implication of myosin VI-based transport

    CYTOSKELETON, Issue 7 2008
    Hirofumi Sakaguchi
    Abstract Hair cell stereocilia are apical membrane protrusions filled with uniformly polarized actin filament bundles. Protein tyrosine phosphatase receptor Q (PTPRQ), a membrane protein with extracellular fibronectin repeats has been shown to localize at the stereocilia base and the apical hair cell surface, and to be essential for stereocilia integrity. We analyzed the distribution of PTPRQ and a possible mechanism for its compartmentalization. Using immunofluorescence we demonstrate that PTPRQ is compartmentalized at the stereocilia base with a decaying gradient from base to apex. This distribution can be explained by a model of transport directed toward the stereocilia base, which counteracts diffusion of the molecules. By mathematical analysis, we show that this counter transport is consistent with the minus end-directed movement of myosin VI along the stereocilia actin filaments. Myosin VI is localized at the stereocilia base, and exogenously expressed myosin VI and PTPRQ colocalize in the perinuclear endosomes in COS-7 cells. In myosin VI-deficient mice, PTPRQ is distributed along the entire stereocilia. PTPRQ-deficient mice show a pattern of stereocilia disruption that is similar to that reported in myosin VI-deficient mice, where the predominant features are loss of tapered base, and fusion of adjacent stereocilia. Thin section and freeze-etching electron microscopy showed that localization of PTPRQ coincides with the presence of a dense cell surface coat. Our results suggest that PTPRQ and myosin VI form a complex that dynamically maintains the organization of the cell surface coat at the stereocilia base and helps maintain the structure of the overall stereocilia bundle. Cell Motil. Cytoskeleton 2008. Published 2008 Wiley-Liss, Inc. [source]

    The deaf mouse mutant whirler suggests a role for whirlin in actin filament dynamics and stereocilia development

    CYTOSKELETON, Issue 7 2007
    Mette M. Mogensen
    Abstract Stereocilia, finger-like projections forming the hair bundle on the apical surface of sensory hair cells in the cochlea, are responsible for mechanosensation and ultimately the perception of sound. The actin cytoskeleton of the stereocilia contains hundreds of tightly cross-linked parallel actin filaments in a paracrystalline array and it is vital for their function. Although several genes have been identified and associated with stereocilia development, the molecular mechanisms responsible for stereocilia growth, maintenance and organisation of the hair bundle have not been fully resolved. Here we provide further characterisation of the stereocilia of the whirler mouse mutant. We found that a lack of whirlin protein in whirler mutants results in short stereocilia with larger diameters without a corresponding increase in the number of actin filaments in inner hair cells. However, a decrease in the actin filament packing density was evident in the whirler mutant. The electron-density at the tip of each stereocilium was markedly patchy and irregular in the whirler mutants compared with a uniform band in controls. The outer hair cell stereocilia of the whirler homozygote also showed an increase in diameter and variable heights within bundles. The number of outer hair cell stereocilia was significantly reduced and the centre-to-centre spacing between the stereocilia was greater than in the wildtype. Our findings suggest that whirlin plays an important role in actin filament packing and dynamics during postnatal stereocilium elongation. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source]

    Health Care Supply Chain Design: Toward Linking the Development and Delivery of Care Globally,

    DECISION SCIENCES, Issue 2 2009
    Kingshuk K. Sinha
    ABSTRACT This article is motivated by the gap between the growing demand and available supply of high-quality, cost-effective, and timely health care, a problem faced not only by developing and underdeveloped countries but also by developed countries. The significance of this problem is heightened when the economy is in recession. In an attempt to address the problem, in this article, first, we conceptualize care as a bundle of goods, services, and experiences,including diet and exercise, drugs, devices, invasive procedures, new biologics, travel and lodging, and payment and reimbursement. We then adopt a macro, end-to-end, supply chain,centric view of the health care sector to link the development of care with the delivery of care. This macro, supply chain,centric view sheds light on the interdependencies between key industries from the upstream to the downstream of the health care supply chain. We propose a framework, the 3A-framework, that is founded on three constructs,affordability, access, and awareness,to inform the design of supply chain for the health care sector. We present an illustrative example of the framework toward designing the supply chain for implantable device,based care for cardiovascular diseases in developing countries. Specifically, the framework provides a lens for identifying an integrated system of continuous improvement and innovation initiatives relevant to bridging the gap between the demand and supply for high-quality, cost-effective, and timely care. Finally, we delineate directions of future research that are anchored in and follow from the developments documented in the article. [source]

    Asymmetric formation and possible function of the primary pore canal in plutei of Temnopleurus hardwicki

    Yoshinobu Hara
    The development and possible function of the primary pore canal (PPC) in plutei of the sea urchin Temnopleurus hardwicki was examined by immunochemistry, electron microscopy and microsurgery. Left and right PPC that extended from coelomic sacs in plutei contained a bundle of cilia with a 9 + 2 structure that was initially detected as a group of anti-acetylated tubulin antibody-binding granules in the epithelium of coelomic sacs in 28 h postfertilization (PF) prism larvae. The granules extended to be a bundle of fibers toward the larval dorsal surface, concurrent with formation of the PPC on both sides, over the next 4 h. The cilia in both PPC beat actively. However, the PPC on the right side disappeared by approximately 55 h PF, establishing left,right asymmetry by 60 h PF (the four-arm pluteus stage). The numbers of cilia in the left and right PPC in 56 h PF plutei were five and eight, respectively. Microsurgical removal of the coelomic sac from both sides or the left side only from 26 h PF prism larvae decreased body width to 64 and 91% of normal width by 50 h PF pluteus stage, respectively, whereas that of the right PPC did not. These observations suggest that PPC contribute to the maintenance of normal body width, and that there is asymmetrical activity between the left and right PPC. [source]

    Can Trade Help Poor People?

    Market Access in Tanzania, The Role of Trade, Trade Policy
    Many development economists prescribe trade as a poverty-reducing formula. But how is this elixir supposed to work? This article contributes to the lively debate on this topic with household evidence from Tanzania , a poor country even within sub-Saharan Africa, the poorest region. About 81% of the poor work in agriculture, which accounts for 88% of the export bundle. The article describes existing poverty and then evaluates the poverty-reduction potential of trade, trade policy and market access. The article extends the analysis by simulating tariff changes and four switching scenarios that swap some poor households into trade-related sectors, such as cash cropping or tourism, to project national poverty reductions of up to 5.6% and household income increases of up to 21.5%. [source]