bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture network engineering for hydraulic fracturing
Authors: Pettitt Will , Pierce Matt , Damjanac Branko , Hazzard Jim , Lorig Loren , Fairhurst Charles , Gil Ivan , Sanchez Marisela , Nagel Neal , Reyes-Montes Juan , Young R. Paul
Published: August 2011

Fracture network engineering (FNE) involves the design, analysis, modeling, and monitoring of infield activities aimed at enhancing or minimizing rock mass disturbance. FNE relies specifically on advanced techniques to model fractured rock masses and correlate microseismic (MS) field observations with simulated microseismicity generated from these models. Hydrofracture stimulation is an example where FNE is playing a role, with hydraulic treatments now being widely used to optimize production volumes and extraction rates in petroleum reservoirs, enhanced geothermal systems, and preconditioning operations in caving mines. MS monitoring is now becoming a standard tool for evaluating the geometry and evolution of the fracture network induced during a given treatment, principally by source locating MS hypocenters and visualizing these with respect to the treatment volume and infrastructure. The integrated use of synthetic rock mass (SRM) modeling of the hydrofracturing with enhanced microseismic analysis (EMA) within FNE provides a feedback loop in which SRM is enhanced and constrained by the information provided by the MS data. This improves interpretation via direct observation of the micromechanics within the distinct element models used. Recent developments in both SRM and EMA technologies are described using case studies of the techniques applied to hydrofracture stimulations. We identify and discuss some future developmental challenges these technologies face, including their further integration and validation so as to provide more efficient and robust application of the FNE approach.
Introduction to this special section: Multiple attenuation
Authors: Goodway Bill
Published: August 2011

Multiples? What multiples? This was the reply to my questioning of the seismic-to-synthetic log mis-tie shown in Figure 1. My inquiry followed a request for technical assistance in an AVO inversion project by a young entry-level geophysicist interpreting the thin tram-track reservoirs typical of the Western Canadian Sedimentary Basin (WCSB). The project had been initiated with this log tie to establish the spectral characteristics of a wavelet needed for inversion and despite being at the end of the AVO-compliant processing flow, I suggested that we take a step back to deal with the obvious multiple contamination clearly visible within the zone of interest. I was met with blank stares, as there had been no discussion about multiples. It even crossed my mind that maybe multiples had not been a part of my young colleague's education and training. If this was indeed the case, then it was not her oversight, as I had seen no new technology or even convention presentations trying to address this persistently insidious land internal-multiple problem since the last time I was fully engaged in the mid 1990s.
Multiple attenuation: Recent advances and the road ahead (2011)
Authors: Weglein Arthur B. , Hsu Shih-Ying , Terenghi Paolo , Li Xu , Stolt Robert H.
Published: August 2011

Multiple removal is a longstanding problem in exploration seismology. Although methods for removing multiples have advanced and have become more effective, the concomitant industry trend toward more complex exploration areas and difficult plays has often outpaced advances in multiple-attenuation technology. The topic of multiples, and developing ever more effective methods for their removal, remains high in terms of industry interest, priority and research investment. The question as to whether today, in 2011, multiples or multiple removal is winning is a way of describing what we are about to discuss. This paper focuses on recent advances, progress and strengths and limitations of current capability and a prioritized list of open issues that need to be addressed.
Exemplifying the specific properties of the inverse scattering series internal-multiple attenuation method that reside behind its capability for complex onshore and marine multiples
Authors: Terenghi Paolo , Hsu Shih-Ying , Weglein Arthur B. , Li Xu
Published: August 2011

The world of petroleum exploration constantly demands higher efficacy at every link in the data processing chain, from preconditioning to imaging and inversion. Within that chain, the removal of internal multiples constitutes a particularly resilient problem, whose resolution has only partially benefited from the advent of the data-driven technologies which have transformed the practice of free-surface multiple elimination.
Elimination of land internal multiples based on the inverse scattering series
Authors: Luo Yi , Kelamis Panos G. , Fu Qiang , Huo ShouDong , Sindi Ghada , Hsu Shih-Ying , Weglein Arthur B.
Published: August 2011

Despite the explosion of new, innovative technologies in the area of multiple identification and subsequent attenuation, their applicability is mostly limited to marine environments especially in deep water. In land seismic data sets however, the application of such multiple-elimination methodologies is not always straightforward and in many cases poor results are obtained. The unique characteristics of land seismic data (i.e., noise, statics and coupling) are major obstacles in multiple estimation and subsequent elimination. The well-defined surface multiples present in marine data are rarely identifiable in land data. Particularly in desert terrains with a complex near surface and low-relief structures, surface multiples hardly exist. In most cases, we are dealing with so called “near-surface-related multiples.” These are primarily internal multiples generated within the complex near surface.
Enhanced demultiple by 3D SRME using dual-sensor measurements
Authors: van Borselen Roald , Hegge Rob , Martin Tony , Barnes Simon , Aaron Peter
Published: August 2011

In recent years, dual-sensor recording has been introduced to marine seismic acquisition with reported benefits such as the increased bandwidth of the acquired seismic signal, improved signal-to-noise ratios due to deep-tow streamers, and operational efficiency due to an increased weather window.
Buildings Subjected to Recurring Earthquakes: A Tale of Three Cities
Authors: Bayhan Beyhan , Gülkan Polat
Published: August 2011

Three different buildings built according to the same design have experienced three different near-field strong ground motions over a period of 11 years in three different cities in Turkey. The input motion was known for each because strong-motion sensors were located adjacent or close to the buildings. We examine the performance of the five-story, reinforced concrete-frame buildings. Bidirectional nonlinear time history and nonlinear static analyses on 3-D analytical models are performed. The principal focus is to assess whether the analytical model of the buildings could indicate column-beam damage consistent with that observed at the sites after the earthquakes. Results illustrate that nonlinear time history analyses are capable of indicating the occurrence of shear failure in captive columns; however, they overestimate the global damage. The overestimation is greater where the building sustained a pulse-type motion without significant distress. It appears that difference between visual observations and analytical results persists.
Testing Protocol for Experimental Seismic Qualification of Distributed Nonstructural Systems
Authors: Retamales Rodrigo , Mosqueda Gilberto , Filiatrault Andre , Reinhorn Andrei
Published: August 2011

Building codes and standards now require seismic qualification of mechanical and electrical equipment and their mounting systems in important buildings to ensure that they remain functional during and after major seismic events. To better understand the seismic behavior of nonstructural building contents and equipment, experimental procedures have been proposed for either displacement or acceleration sensitive nonstructural components, through racking or shake table protocols, respectively. However, certain types of nonstructural systems are sensitive to both accelerations and interstory drifts. An innovative testing protocol is proposed that can subject nonstructural systems to the combined accelerations and interstory drifts expected within multistory buildings during seismic shaking. Moreover, the proposed protocol, when used with equipment such as the University at Buffalo Nonstructural Component Simulator (UB-NCS), allows for the assessment of the seismic performance of distributed nonstructural systems with multiple attachment points, and the evaluation of seismic interactions between components. The versatility and capabilities of the testing protocol are demonstrated through testing of a full-scale hospital emergency room containing typical nonstructural components and life support medical equipment.
Melanocortin 4 Receptor Activation Protects Against Testicular Ischemia-Reperfusion Injury by Triggering the Cholinergic Antiinflammatory Pathway
Authors: Minutoli Letteria , Bitto Alessandra , Squadrito Francesco , Irrera Natasha , Rinaldi Mariagrazia , Nicotina Piero Antonio , Arena Salvatore , Magno Carlo , Marini Herbert , Spaccapelo Luca , Ottani Alessandra , Giuliani Daniela , Romeo Carmelo , Guarini Salvatore , Antonuccio Pietro , Altavilla Domenica
Published: August 2011

Melanocortins (MC) trigger a vagus nerve-mediated cholinergic-antiinflammatory pathway projecting to the testis. We tested whether pharmacological activation of brain MC receptors might protect the testis from the damage induced by ischemia-reperfusion. Adult male rats were subjected to 1-h testicular ischemia, followed by 24-h reperfusion [testicular ischemia-reperfusion (TI/R)]. Before TI/R, groups of animals were subjected to bilateral cervical vagotomy, or pretreated with the nicotinic acetylcholine receptor antagonist chlorisondamine or the selective MC4 receptor antagonist HS024. Immediately after reperfusion, rats were ip treated with saline or the MC analog [Nle4,D-Phe7]α-melanocyte-stimulating hormone (NDP-α-MSH) (340 μg/kg). We evaluated testicular IL-6 and TNF-α by Western blot analysis and organ damage by light microscopy. Some experimental groups were prepared for neural efferent activity recording along the vagus nerve starting 30 min after treatment with NDP-α-MSH or saline, and for a 30-min period. Additional groups of TI/R rats were treated for 30 d with saline, NDP-α-MSH, chlorisondamine plus NDP-α-MSH, or HS024 plus NDP-α-MSH to evaluate spermatogenesis, organ damage, and the apoptosis machinery. After a 24-h reperfusion, in TI/R saline-treated rats, there was an increase in IL-6 and TNF-α expression and a marked damage in both testes. NDP-α-MSH inhibited IL-6 and TNF-α expression, decreased histological damage, and increased neural efferent activity. Furthermore, NDP-α-MSH administration for 30 d greatly improved spermatogenesis, reduced organ damage, and inhibited apoptosis. All positive NDP-α-MSH effects were abrogated by vagotomy, chlorisondamine, or HS024. Our data suggest that selective MC4 receptor agonists might be therapeutic candidates for the management of testicular torsion.
Visualizing Microtubule-Dependent Vasopressin Type 2 Receptor Trafficking Using a New High-Affinity Fluorescent Vasopressin Ligand
Authors: Chen Sylvia , Webber Matthew J. , Vilardaga Jean-Pierre , Khatri Ashok , Brown Dennis , Ausiello Dennis A. , Lin Herbert Y. , Bouley Richard
Published: August 2011

The vasopressin receptor type 2 (V2R) is the major target of vasopressin (VP) in renal epithelial cells. Although it is known that VP induces V2R internalization, accumulation in the perinuclear area, and degradation, the V2R intracellular trafficking pathways remain elusive. We visualized this process by developing a new fluorescent VP analog tagged by tetramethylrhodamine (TMR)-[Lys-(PEG)2-Suc-TMR8]VP or (VPTMR). This ligand is fully functional as revealed by its high binding affinity toward V2R [(Kd) =157 ± 52 nm] and ability to increase intracellular cAMP 32-fold. VPTMR induced V2R internalization in LLC-PK1 cells expressing either a FLAG-tagged receptor (FLAG-V2R) or V2R C-terminally tagged with green fluorescent protein (GFP) (V2R-GFP). After internalization, VPTMR and V2R-GFP colocalized in the perinuclear area, suggesting that the hormone and receptor traffic along the same pathway. VPTMR and V2R colocalized initially with the early endosome markers EEA1 and Rab5, and later with the recycling and late endosome markers Rab11 and Rab25. Epifluorescence microscopy of LLC-PK1 cells expressing GFP-tagged microtubules (MT) showed that VPTMR-containing vesicles travel along the MT network, and even remain attached to MT during the metaphase and anaphase of mitosis. Colchicine, a MT-depolymerizing agent, abolished perinuclear accumulation of VPTMR, and Western blot analysis showed that VP-induced V2R-GFP degradation is markedly retarded, but not abolished, by colchicine (10 μM). We conclude that the new VPTMR ligand is suitable for dissecting V2R and VP internalization and trafficking in cells, and that V2R trafficking and down-regulation is an MT-dependent mechanism.
From ad hoc Down's syndrome screening to a functional uniform national screening programme
Authors: Ward Pat
Published: August 2011

The implementation of a uniform service for Down's syndrome screening in England has been ongoing since it was first set out in 2001 that all women would be offered screening. The main aim has been to improve the detection rate while retaining a low screen positive rate (Spr) using a combined screening strategy. It has been a major challenge to ensure that the measurement of the nuchal translucency using ultrasound is performed well in each hospital and that sonographers are supported in meeting that challenge. The service is now beginning to meet the national policy that all units must offer combined screening and that it reaches a 90% detection rate for a 2% Spr.
Pricing Multiple Products with the Multinomial Logit and Nested Logit Models: Concavity and Implications
Authors: Li Hongmin , Huh Woonghee Tim
Published: August 2011

We consider the problem of pricing multiple differentiated products with the nested logit model and, as a special case, the multinomial logit model. We prove that concavity of the total profit function with respect to market share holds even when price sensitivity may vary with products. We use this result to analytically compare the optimal monopoly solution to oligopolistic equilibrium solutions. To demonstrate further applications of the concavity result, we consider several multiperiod dynamic models that incorporate the pricing of multiple products in the context of inventory control and revenue management, and establish structural results of the optimal policies.
Current Therapeutic Uses, Pharmacology, and Clinical Considerations of Neuromuscular Blocking Agents for Critically III Adults
Authors: Warr Julia , Thiboutot Zoé , Rose Louise , Mehta Sangeeta , Burry Lisa D
Published: August 2011

Objective:

To summarize literature describing use of neuromuscular blocking agents (NMBAs) for common critical care indications and provide a review of NMBA pharmacology, pharmacokinetics, dosing, drug interactions, monitoring, complications, and reversal.

Data Sources:

Searches of MEDLINE (1975-May 2011). EMBASE (1960-May 2011), and Cumulative Index to Nursing and Allied Health Literature (1981-May 2011) were conducted to identify observational and interventional studies evaluating the efficacy or safety of NMBAs for management of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), status asthmaticus, elevated intracranial pressure (ICP), and therapeutic hypothermia.

Study Selection And Data Extraction:

We excluded case reports, animal- or laboratory-based studies, trials describing NMBA use during rapid sequence intubation or in the operating room, and studies published in languages other than English or French.

Data Synthesis:

Clinical applications of NMBAs in intensive care include, but are not limited to, immobilizing patients for procedural interventions, decreasing oxygen consumption, facilitating mechanical ventilation, reducing intracranial pressure, preventing shivering, and management of tetanus. Recent data on ARDS demonstrated that early application of NMBAs improved adjusted 90-day survival for patients with severe lung injury. These results may lead to increased use of these drugs. While emerging data support the use of cisatracurium in select patients with ALI/ARDS, current literature does not support the use of one NMBA over another for other critical care indications. Cisatracurium may be kinetically preferred for patients with organ dysfunction. Close monitoring with peripheral nerve stimulation is recommended with sustained use of NMBAs to avoid drug accumulation and minimize the risk for adverse drug events. Reversal of paralysis is achieved by discontinuing therapy or, rarely, the use of anticholinesterases.

Conclusions:

NMBAS are high-alert medications used to manage critically ill patients. New data are available regarding the use of these agents for treatment of ALI/ARDS and status asthmaticus, management of elevated ICP, and provision of therapeutic hypothermia after cardiac arrest. To improve outcomes and promote patient safety, intensive care unit team members should have a thorough knowledge of this class of medications.
Regulation of MET by FOXP2, Genes Implicated in Higher Cognitive Dysfunction and Autism Risk
Authors: Mukamel Zohar , Konopka Genevieve , Wexler Eric , Osborn Gregory E. , Dong Hongmei , Bergman Mica Y. , Levitt Pat , Geschwind Daniel H.
Published: August 2011

Autism spectrum disorder (ASD) is a highly heritable, behaviorally defined, heterogeneous disorder of unknown pathogenesis. Several genetic risk genes have been identified, including the gene encoding the receptor tyrosine kinase MET, which regulates neuronal differentiation and growth. An ASD-associated polymorphism disruptsMETgene transcription, and there are reduced levels of MET protein expression in the mature temporal cortex of subjects with ASD. To address the possible neurodevelopmental contribution ofMETto ASD pathogenesis, we examined the expression and transcriptional regulation ofMETby a transcription factor, FOXP2, which is implicated in regulation of cognition and language, two functions altered in ASD.METmRNA expression in the midgestation human fetal cerebral cortex is strikingly restricted, localized to portions of the temporal and occipital lobes. Within the cortical plate of the temporal lobe, the pattern ofMETexpression is highly complementary to the expression pattern of FOXP2, suggesting the latter may play a role in repression of gene expression. Consistent with this, MET and FOXP2 also are reciprocally expressed by differentiating normal human neuronal progenitor cells (NHNPs)in vitro, leading us to assess whether FOXP2 transcriptionally regulatesMET. Indeed, FOXP2 binds directly to the 5′ regulatory region ofMET, and overexpression of FOXP2 results in transcriptional repression ofMET. The expression ofMETin restricted human neocortical regions, and its regulation in part by FOXP2, is consistent with genetic evidence forMETcontributing to ASD risk.
Ketamine Disrupts Theta Modulation of Gamma in a Computer Model of Hippocampus
Authors: Neymotin Samuel A. , Lazarewicz Maciej T. , Sherif Mohamed , Contreras Diego , Finkel Leif H. , Lytton William W.
Published: August 2011

Abnormalities in oscillations have been suggested to play a role in schizophrenia. We studied theta-modulated gamma oscillations in a computer model of hippocampal CA3in vivowith and without simulated application of ketamine, an NMDA receptor antagonist and psychotomimetic. Networks of 1200 multicompartment neurons [pyramidal, basket, and oriens-lacunosum moleculare (OLM) cells] generated theta and gamma oscillations from intrinsic network dynamics: basket cells primarily generated gamma and amplified theta, while OLM cells strongly contributed to theta. Extrinsic medial septal inputs paced theta and amplified both theta and gamma oscillations. Exploration of NMDA receptor reduction across all location combinations demonstrated that the experimentally observed ketamine effect occurred only with isolated reduction of NMDA receptors on OLMs. In the ketamine simulations, lower OLM activity reduced theta power and disinhibited pyramidal cells, resulting in increased basket cell activation and gamma power. Our simulations predict the following: (1) ketamine increases firing rates; (2) oscillations can be generated by intrinsic hippocampal circuits; (3) medial-septum inputs pace and augment oscillations; (4) pyramidal cells lead basket cells at the gamma peak but lag at trough; (5) basket cells amplify theta rhythms; (6) ketamine alters oscillations due to primary blockade at OLM NMDA receptors; (7) ketamine alters phase relationships of cell firing; (8) ketamine reduces network responsivity to the environment; (9) ketamine effect could be reversed by providing a continuous inward current to OLM cells. We suggest that this last prediction has implications for a possible novel treatment for cognitive deficits of schizophrenia by targeting OLM cells.
Cross-Species Conservation of Open-Channel Block by Na Channel β4 Peptides Reveals Structural Features Required for Resurgent Na Current
Authors: Lewis Amanda H. , Raman Indira M.
Published: August 2011

Voltage-gated Na channels in many neurons, including several in the cerebellum and brainstem, are specialized to allow rapid firing of action potentials. Repetitive firing is facilitated by resurgent Na current, which flows upon repolarization as Na channels recover through open states from block by an endogenous protein. The best candidate blocking protein to date is NaVβ4. The sequence of this protein diverges among species, however, while high-frequency firing is maintained, raising the question of whether the proposed blocking action of the NaVβ4 cytoplasmic tail has been conserved. Here, we find that, despite differences in the NaVβ4 sequence, Purkinje cells isolated from embryonic chick have resurgent currents with kinetics and amplitudes indistinguishable from those in mouse Purkinje cells. Furthermore, synthetic peptides derived from the divergent NaVβ4 cytoplasmic tails from five species have the capacity to induce resurgent current in mouse hippocampal neurons, which lack a functional endogenous blocking protein. These data further support a blocking role for NaVβ4 and also indicate the relative importance of different residues in inducing open-channel block. To investigate the contribution of the few highly conserved residues to open-channel block, we synthesized several mutant peptides in which the identities and relative orientations of a phenylalanine and two lysines were disrupted. These mutant peptides produced currents with vastly different kinetics than did the species-derived peptides, suggesting that these residues are required for an open-channel block that approximates physiological resurgent Na current. Thus, if other blocking proteins exist, they may share these structural elements with the NaVβ4 cytoplasmic tail.
Genetic Association of ErbB4 and Human Cortical GABA LevelsIn Vivo
Authors: Marenco Stefano , Geramita Matthew , van der Veen Jan Willem , Barnett Alan S. , Kolachana Bhaskar , Shen Jun , Weinberger Daniel R. , Law Amanda J.
Published: August 2011

NRG1-ErbB4 signaling controls inhibitory circuit development in the mammalian cortex through ErbB4-dependent regulation of GABAergic interneuron connectivity. Common genetic variation in ErbB4 (rs7598440) has been associated with ErbB4 messenger RNA levels in the human cortex and risk for schizophrenia. Recent work demonstrates that Erbb4 is expressed exclusively on inhibitory interneurons, where its presence on parvalbumin-positive cells mediates the effects of NRG1 on inhibitory circuit formation in the cortex. We therefore hypothesized that genetic variation in ErbB4 at rs7598440 would impact indices of GABA concentration in the human cortex. We tested this hypothesis in 116 healthy volunteers by measuring GABA and GLX (glutamate + glutamine) with proton magnetic resonance spectroscopy in the dorsal anterior cingulate gyrus. ErbB4 rs7598440 genotype significantly predicted cortical GABA concentration (p= 0.014), but not GLX (p= 0.51), with A allele carriers having higher GABA as predicted by the allelic impact on ErbB4 expression. These data establish an association of ErbB4 and GABA in human brain and have implications for understanding the pathogenesis of schizophrenia and other psychiatric disorders.
TRPM7 Is Required within Zebrafish Sensory Neurons for the Activation of Touch-Evoked Escape Behaviors
Authors: Low Sean E. , Amburgey Kimberly , Horstick Eric , Linsley Jeremy , Sprague Shawn M. , Cui Wilson W. , Zhou Weibin , Hirata Hiromi , Saint-Amant Louis , Hume Richard I. , Kuwada John Y.
Published: August 2011

Mutations in the gene encoding TRPM7 (trpm7), a member of the Transient Receptor Potential (TRP) superfamily of cation channels that possesses an enzymatically active kinase at its C terminus, cause the touch-unresponsive zebrafish mutanttouchdown. We identified and characterized a new allele oftouchdown, as well as two previously reported alleles, and found that all three alleles harbor mutations that abolish channel activity. Through the selective restoration of TRPM7 expression in sensory neurons, we found that TRPM7's kinase activity and selectivity for divalent cations over monovalent cations were dispensable for touch-evoked activation of escape behaviors in zebrafish.

Additional characterization revealed that sensory neurons were present and capable of responding to tactile stimuli intouchdownmutants, indicating that TRPM7 is not required for sensory neuron survival or mechanosensation. Finally, exposure to elevated concentrations of divalent cations was found to restore touch-evoked behaviors intouchdownmutants. Collectively, these findings are consistent with a role for zebrafish TRPM7 within sensory neurons in the modulation of neurotransmitter release at central synapses, similar to that proposed for mammalian TRPM7 at peripheral synapses.
Extraction of caesium(I) from HNO3 medium using room temperature ionic liquid containing calix[4]crown ligands as the selective extractants
Authors: Ansari S. A. , Mohapatra P. K. , Raut D. R. , Manchanda V. K.
Published: August 2011

Studies on the extraction of Cs(I) from nitric acid medium were carried out using three commercial calix-crown ligands, viz. calix[4]arene-bis-crown-6, calix[4]arene-bis-1,2-benzocrown-6 and calix[4]arene-bis-2,3-naphthocrown-6 dissolved in different room temperature ionic liquids (RTILs), viz. 1-butyl-3-methyl-imidazolium hexafluorophosphate (C4mim·PF6), 1-hexyl-3-methyl-imidazolium hexafluorophosphate (C6mim·PF6) and 1-octyl-3-methyl-imidazolium hexafluorophosphate (C8mim·PF6). The distribution ratio of Cs(I) decreased with increased alkyl chain length of RTILs. The effect of nitric acid concentration on distribution behaviour of Cs(I) by calix[4]arene-bis-1,2-benzocrown-6 was investigated. The extraction of Cs(I) from HNO3 was found to be exothermic and extraction was found to be enthalpy driven. Selective extraction of Cs(I) could be achieved from a mixt ure of various fission product elements like Tc, Mo, Zr, Ce, Ru, La, Ba, and Sr.
Synthesis and incorporation of selenide in pyrite and mackinawite
Authors: Diener Alexander , Neumann Thomas
Published: August 2011

According to performance assessment reports for high-level radioactive waste repositories, 79Se is a radionuclide that could represent a potential threat to the biosphere. Therefore knowledge of its geochemical behavior during its transport in aqueous solutions is fundamental to assess the safety of repository sites. Selenium is often associated with sulfides such as pyrite, a frequent minor constituent of host rocks and bentonite backfills considered for radioactive waste disposal. In this study, we investigated the uptake of Se by Fe sulfides synthesized in batch experiments under anoxic conditions. Results from X-ray diffraction and scanning electron microscopy analyses reveal the formation of pyrite and mackinawite. More than 98% of the Se added to solutions (initial concentration: 10−3–10−6 mol/l) was taken up by the Fe sulfide minerals. Focused ion beam analysis shows an inhomogeneous Se distribution with a higher accumulation in the center of the pyrite grains, probably due to the progressive depletion of Se from solution with regard to S. The results imply that pyrite and its most important precursor phase, mackinawite, are efficient in removing selenium from solution, which may contribute in reducing the mobility of 79Se released from radioactive waste.
Asymmetric ‘Newmark' sliding caused by motions containing severe ‘directivity' and ‘fling' pulses
Authors: GARINI E. , GAZETAS G. , ANASTASOPOULOS I.
Published: August 2011

Sliding of a rigid mass supported on an inclined, seismically shaking plane serves as a conceptual and computational model for a variety of problems in geotechnical earthquake engineering. A series of parametric analyses are presented in the paper using as excitation numerous near-fault-recorded severe ground motions and idealised wavelets, bearing the effects of ‘forward-directivity' and ‘fling-step'. Using as key parameters the angle β of the sloping plane (mimicking the sliding surface), as well as the frequency content, intensity, nature and polarity of the excitation, the paper aims at developing a deeper insight into the mechanics of the asymmetric sliding process and the role of key parameters of the excitation. It is shown that ‘directivity' and ‘fling' affected motions containing long-period acceleration pulses and large velocity steps, are particularly ‘destructive' for the examined systems. The amount of accumulating slip on a steep slope is particularly sensitive to reversal of the polarity of excitation. With some special ground motions, in particular (such as the Sakarya and Yarimca accelerograms, both recorded 3 km from the surface expression of the North Anatolian Fault that ruptured in the 1999 Kocaeli earthquake), what might at first glance appear elusively as ‘small details' in the record may turn out to exert a profound influence on the magnitude of slippage – far outweighing the effects of peak acceleration, peak velocity and Arias intensity. The results are compiled in both dimensionless and dimensional charts, and compared with classical charts from the literature. Finally, it is shown that no convincingly robust correlation could exist between accumulated slip and the Arias intensity of excitation.
Progressive failure of Aznalcóllar dam using the material point method
Authors: ZABALA F. , ALONSO E.E.
Published: August 2011

The material point method, which combines features of finite-element and particle discretisation methods, has been extended to solve coupled flow-deformation problems in granular media. The method is applied to simulate the construction and failure of the Aznalcóllar dam. The brittle foundation clay is characterised by means of a strain-softening Mohr–Coulomb elasto-plastic model. The rupture process of the foundation is associated with a progressive failure mechanism. The model predicts the development of a localised shearing band that initiates at the toe of the dam at some intermediate stage of construction, and propagates downstream and upstream. The shape and position of the failure surface reproduce actual field observations.
Empowering rural communities: simple Water Safety Plans
Authors: Hasan T. J. , Hicking A. , David J.
Published: August 2011

Every year 2800 deaths in Pacific island countries result from diarrhoea, and most are children under five years of age. These tragic diarrheal deaths are preventable as they are often linked to unsafe water, lack of proper sanitation facilities and poor hygienic practices. Effective preventive management through the framework of a drinking Water Safety Plan (WSP) is an efficient mechanism for ensuring the safe quality of drinking water thereby reducing the burden of water related diseases. The large proportion (81%) of people in Pacific island countries living in rural or outer island communities mostly have their own water supply (for example rainwater tanks or hand-dug wells), and often the water is consumed untreated. The remoteness and isolation of these rural communities prevent national surveillance authorities to regularly visit and provide advice on drinking water safety issues. In such circumstances empowering rural communities to ensure the safety of their drinking water, through trained local facilitators, could be promoted and utilised effectively. However, WSPs for rural communities have to be relatively simple hence tools such as modified sanitary inspections and the presence/absence hydrogen sulfide test could be used. The approach of empowering communities through trained local facilitators to promote the WSP framework has been implemented in the Republic of Marshall Islands (RMI). Positive feedback has been received by trained facilitators in RMI on the use of modified sanitary inspections (translated into Marshallese) and the hydrogen sulfide test. It is believed that the approach of empowering communities on WSPs through training local facilitators and equipping them with the above mentioned simple tools is effective and has potential for further replication in rural Pacific communities to improve drinking water quality and reduce the burden of water related diseases.
Smoothing Gene Expression Data with Network Information Improves Consistency of Regulated Genes
Authors: Dørum Guro , Snipen Lars , Solheim Margrete , Saebo Solve
Published: August 2011

Gene set analysis methods have become a widely used tool for including prior biological knowledge in the statistical analysis of gene expression data. Advantages of these methods include increased sensitivity, easier interpretation and more conformity in the results. However, gene set methods do not employ all the available information about gene relations. Genes are arranged in complex networks where the network distances contain detailed information about inter-gene dependencies. We propose a method that uses gene networks to smooth gene expression data with the aim of reducing the number of false positives and identify important subnetworks. Gene dependencies are extracted from the network topology and are used to smooth genewise test statistics. To find the optimal degree of smoothing, we propose using a criterion that considers the correlation between the network and the data. The network smoothing is shown to improve the ability to identify important genes in simulated data. Applied to a real data set, the smoothing accentuates parts of the network with a high density of differentially expressed genes.
Multiproduct Duopoly with Vertical Differentiation
Authors: Cheng Yi-Ling , Peng Shin-Kun , Tabuchi Takatoshi
Published: August 2011

This paper investigates a two-stage competition in a vertically differentiated industry, where each firm produces an arbitrary number of similar qualities and sells them to heterogeneous consumers. The number of products, qualities, prices, and the extent of the market coverage are endogenously determined. We show that when unit costs of quality improvement are increasing and quadratic, each firm has an incentive to provide a disconnected set of similar qualities approximating a continuum. The finding contrasts sharply with the single-quality outcome when the market coverage is exogenously determined. We also show that allowing for multiple qualities intensifies the level of competition, lowers the profit of each firm, and raises the consumer surplus and the social welfare in comparison to the single-quality duopoly.
A lutetium pvc membrane sensor based on (2-oxo-1,2-diphenylethylidene)-n-phenylhydrazinecarbothioamide
Authors: Ali Hassan , Ganjali Reza , Faridbod Farnoush
Published: August 2011

Based on the former experience on the design and construction of metal ions
sensors, especially those of high sensitivity for lanthanides,
(2-oxo-1,2-diphenylethylidene)-N-phenylhydrazinecarbothioamide (PHCT) was
used to construct a Lu3+ PVC sensor exhibiting a Nernstian slope of 19.8?0.3
mV decade-1. The sensor was found to function well over a concentration range
of 1.0?10-2 and 1.0?10-6 mol L-1 of the target ion with a detection limit of
6.8?10-7 mol L-1. The sensor selectivity against many common alkaline,
alkaline earth, transition, heavy metals and specially lanthanide ions was
very good and it functioned well in the pH range 2.5 - 8.7. Having a lifetime
of at least 2 months and a short response time of ?5 s, the sensor was
successfully used as an indicator electrode in the potentiometric titration
of Lu3+ ions.
Risk Factors for Self-Harm in Children and Adolescents Admitted to a Mental Health Inpatient Unit
Authors: de Kloet Liselotte , Starling Jean , Hainsworth Cassandra , Berntsen Ellen , Chapman Lucy , Hancock Karen
Published: August 2011

Objective: The aim of this study was to identify risk factors for self-harm for children and adolescents in a mental health inpatient unit.

Methods: A retrospective file audit of patient files over three years (2006–2009) was conducted to determine risk factors associated with self-harm in children and adolescents admitted to a mental health unit. A checklist of potential factors was based on risk factors found in a review of the literature including demographic information, diagnosis, home situation, environmental stressors, childhood trauma and previous mental health care. The study compared those who self-harmed with a control group who did not self-harm.

Results: There were 150 patients who self-harmed (mean age 14 years) and 56 patients who did not self-harm with a mean age of 13 years. Several factors were identified that increased the likelihood of self-harm, including a diagnosis of depression, female gender, increasing age, being Australian-born, living with a step parent, not having received previous mental health care, having a history of trauma, and having other stressors including problems within the family.

Conclusions: While increasing age, female gender, a history of trauma and a diagnosis of depression are well known as risk factors for self-harm, this study confirms that family factors, in particular living with a step parent, significantly add to the risk. Child and adolescent services should be aware of the increased risk of self-harm in young people with mental health problems who live in blended families. Treatment approaches need to involve parents as well as the child or young person.
Editorial & The Lesson of Sirat-Un-Nabi (P.B.U.H.)
Authors: Editor The
Published: August 2011

DOI: http://dx.doi.org/10.3329/bjms.v4i3.8229BJMS 1997; 4(3): 6
Correlation of MIC with Disc Sensitivity Test of Ampicillin, Amoxycillin and Tetracycline
Authors: Haque AKM Shamsul , Talukder MA Samad , Rafiquzzaman Md , Sultana Sakina , Saha Pijus , Chakladar A Hakim
Published: August 2011

DOI: http://dx.doi.org/10.3329/bjms.v4i3.8230BJMS 1997; 4(3): 7-11
History of Medicine - Contribution of Al-Beruni in Biology
Authors: Khan MS
Published: August 2011

DOI: http://dx.doi.org/10.3329/bjms.v4i3.8234BJMS 1997; 4(3): 38-40
Risk Factors Analysis and Angiographic Profile in Postmenopausal Women with Coronary Artery Disease
Authors: Majumder AAS , Nasrin S , Reza AQM , Chowdhury MAU
Published: August 2011

Background : Postmenopausal women are at greater risk for coronary artery disease (CAD) than premenopausal women. This may be due to deprivation of estrogen, which acts directly and indirectly on the vasculature. In light of this finding the aim of the study was to find the relation of serum estrogen level with severity of atherosclerotic lesion and number of risk factors in CAD among postmenopausal women. Methods: One hundred postmenopausal women undergoing coronary angiography (CAG) were studied. Among them 50 patients with estrogen level <25 pg/ml constituted study Group I and another 50 postmenopausal women with >25 pg/ml constituted study Group II. Serum estrogen level was measured by radioimmunoassay. Other important risk factors like dyslipidaemia, diabetes mellitus, hypertension, family history of CAD, smoking and waist circumference were evaluated between the 2 groups of patients. CAG findings were analyzed by eye estimation and by Gensini score. Results: All the risk factors were significantly higher in Group I patients than that of Group II. Among the risk factors hypertension was most prevalent (64%) in Group I and dyslipidaemia (40%) in Group II. Multivariate regression analysis showed that serum estrogen was a strong and an independent predictor of CAD (p=0.001) when considered with other standard risk factors. Association between the angiographic severity of CAD and serum estrogen level were evaluated and negative correlation was observed, i.e. lower the serum estrogen level higher the vessel score. Conclusion: In postmenopausal women serum estrogen level is a strong & an independent predictor of CAD. It is also found that low estrogen group of postmenopausal women with CAD have more severe atherosclerotic lesions in comparison to the group with normal estrogen level. Keywords: Risk factor, Coronary artery disease, Postmenopausal women, Angiographic profile. DOI: http://dx.doi.org/10.3329/cardio.v1i2.8235 Cardiovasc. j. 2009; 1(2): 161-164
Noninvasive Estimation of PCWP with Doppler Transmitral Flow Velocity Pattern in Patients with Coronary Artery Disease
Authors: Tamanna RJ , Jahan R , Akanda AK , Reza AQM , Zaher A
Published: August 2011

Background: Pulmonary capillary wedge pressure is an important clinical marker of cardiac function. Recent studies have demonstrated Doppler transmitral flow velocity pattern could be useful in assessing PCWP no invasively in patient with known heart disease. Objective: The aims of the study were to correlate the Pulmonary Capillary Wedge Pressure (PCWP) estimated by Doppler echocardiography with that obtained at cardiac catheterization and to evaluate the feasibility and accuracy of Doppler echocardiographic data. Method: All patients underwent simultaneous cardiac catheterization and were studied by Doppler echocardiography. Mitral flow velocity variables & maximal left atrial volume (MLAV) were correlated with invasive PCWP by both single & multilinear regression analysis. Result: A statistically significant negative correlation of deceleration time (r=-0.483; p=0.001) and ejection fraction (r=-0.334; p=0.01) and a statistically significant positive correlation of peak E wave (r=0.345; p=0.01) and deceleration rate (r=0.651; p=0.001 were found with catheter derived PCWP. Multiple regression analysis was used to derive an equation for noninvasive estimation of PCWP. Equation. With 2-D Echo + Mitral flow variables: PCWP = 1.43 X DR + 1.32 X E/A – 0.024 X DT + .02 X MLAV + 9.2. Conclusion: The correlation coefficient between measured and estimated PCWP from the equation was (r=0.678). Data indicated that in patients with CAD the noninvasive assessment of transmitral flow velocity pattern by Doppler echocardiography could predict PCWP with a clinically meaningful degree of accuracy. Key words: Pulmonary capillary wedge pressure, Doppler echocardiography, Coronary artery disease, Cardiac catheterization. DOI: http://dx.doi.org/10.3329/cardio.v1i2.8236 Cardiovasc. j. 2009; 1(2): 174-182
Aberrant Signaling Pathways in Glioma
Authors: Nakada Mitsutoshi , Kita Daisuke , Watanabe Takuya , Hayashi Yutaka , Teng Lei , Pyko Ilya V. , Hamada Jun-Ichiro
Published: August 2011

Glioblastoma multiforme (GBM), a WHO grade IV malignant glioma, is the most common and lethal primary brain tumor in adults; few treatments are available. Median survival rates range from 12–15 months. The biological characteristics of this tumor are exemplified by prominent proliferation, active invasiveness, and rich angiogenesis. This is mainly due to highly deregulated signaling pathways in the tumor. Studies of these signaling pathways have greatly increased our understanding of the biology and clinical behavior of GBM. An integrated view of signal transduction will provide a more useful approach in designing novel therapies for this devastating disease. In this review, we summarize the current understanding of GBM signaling pathways with a focus on potential molecular targets for anti-signaling molecular therapies.
Synthesis and Hydrolytic Degradation of Substituted Poly(DL-Lactic Acid)s
Authors: Tsuji Hideto , Eto Takehiko , Sakamoto Yuzuru
Published: August 2011

Non-substituted racemic poly(DL-lactic acid) (PLA) and substituted racemic poly(DL-lactic acid)s or poly(DL-2-hydroxyalkanoic acid)s with different side-chain lengths, i.e., poly(DL-2-hydroxybutanoic acid) (PBA), poly(DL-2-hydroxyhexanoic acid) (PHA), and poly(DL-2-hydroxydecanoic acid) (PDA) were synthesized by acid-catalyzed polycondensation of DL-lactic acid (LA), DL-2-hydroxybutanoic acid (BA), DL-2-hydroxyhexanoic acid (HA), and DL-2-hydroxydecanoic acid (DA), respectively. The hydrolytic degradation behavior was investigated in phosphate-buffered solution at 80 and 37 °C by gravimetry and gel permeation chromatography. It was found that the reactivity of monomers during polycondensation as monitored by the degree of polymerization (DP) decreased in the following order: LA > DA > BA > HA. The hydrolytic degradation rate traced by DP and weight loss at 80 °C decreased in the following order: PLA > PDA > PHA > PBA and that monitored by DP at 37 °C decreased in the following order: PLA > PDA > PBA > PHA. LA and PLA had the highest reactivity during polymerization and hydrolytic degradation rate, respectively, and were followed by DA and PDA. BA, HA, PBA, and PHA had the lowest reactivity during polymerization and hydrolytic degradation rate. The findings of the present study strongly suggest that inter-chain interactions play a major role in the reactivity of non-substituted and substituted LA monomers and degradation rate of the non-substituted and substituted PLA, along with steric hindrance of the side chains as can be expected.
Li+ Selective Podand-Type Fluoroionophore Based on a Diphenyl Sulfoxide Derivative Bearing Two Pyrene Groups
Authors: Nishimura Yukihiro , Takemura Tetsuo , Arai Sadao
Published: August 2011

New podand-type fluoroionophores having two pyrene moieties: 2,2´-bis(1-pyrenylacetyloxy)diphenyl sulfide (3), 2,2´-bis(1-pyrenylacetyloxy)diphenyl sulfoxide (4), and 2,2´-bis(1-pyrenylacetyloxy)diphenyl sulfone (5), have been synthesized by connecting two 1-pyrenecarbonylmethyl groups with the two hydroxy groups of 2,2´-dihydroxydiphenyl sulfide, sulfoxide, and sulfone, respectively. Their complexation behavior toward alkali metal ions was examined by fluorescence spectroscopy. Among these fluoroionophores, compound 4, having a sulfinyl group, showed high selectivity toward Li+.
Symmetry Aspects of the Band Structure and Motion Equations Applied in Calculating the Cyclotron Frequency of Electrons in Metals
Authors: Olszewski Stanislaw , Roliński Tomasz
Published: August 2011

Cyclotron frequency of a crystal electron is, in general, not an easily accessible parameter. Nevertheless, its calculation can be simplified when the symmetry properties of the band structure and those of the motion equations in the magnetic field are simultaneously taken into account. In effect, a combined symmetry of the electron Hamiltonian and that of the Lorentz equation provide us with a non-linear oscillator problem of high symmetry. In the next step, the kinetic energy of the oscillator can be separated from the whole of electron energy and applied in a new kind of calculation of the cyclotron frequency which is much more simple than before. In consequence, a detailed approach to the electron circulation, also in more complex band structures, becomes a relatively easy task. For different crystal lattices of cubic symmetry taken as examples the cyclotron frequency of the present and a former method are compared numerically giving the same results.