bluuebunny/crossref_metadata_2025 huggingface dataset:
Artesunate/Amodiaquine Malaria Treatment for Equatorial Guinea (Central Africa)
Authors: Charle Pilar , Berzosa Pedro , de Lucio Aida , Raso José , Nseng Nchama Gloria , Benito Agustín
Published: March 2013

The objectives of this study were: 1) to evaluate the safety and efficacy of combination artesunate (AS)/amodiaquine (AQ) therapy, and 2) to determine the difference between recrudescence and resistance. An in vivo efficacy study was conducted in Equatorial Guinea. A total of 122 children 6–59 months of age from two regional hospitals were randomized and subjected to a 28-day clinical and parasitological follow-up. A blood sample on Whatman paper was taken on Days 0, 7, 14, 21, and 28 or on any day in cases of treatment failure, with the parasite DNA then being extracted for molecular analysis purposes. A total of 4 children were excluded, and 9 cases were lost to follow-up. There were 17 cases of late parasitological failure, 3 cases of late clinical failure, and 89 cases of adequate clinical and parasitological response. The parasitological failure rate was 18.3% (20 of 109) and the success rate 81.70% (95% confidence interval [72.5–87.9%]). After molecular correction, real treatment efficacy stood at 97.3%. Our study showed the good efficacy of combination AS/AQ therapy. This finding enabled this treatment to be recommended to Equatorial Guinea's National Malaria Control Program to change the official treatment policy as of March 2008.
The Diagnostic Peritoneal Lavage: A Brief Review of the Current Literature and an Analysis of Its use and Teaching in Canada
Authors: Clarkson Colin A , Boone Darrell
Published: March 2013

Introduction

The vast majority of the published data on the appropriate use of the diagnostic peritoneal lavage (DPL) is dated. Currently in Canada, there is a significant grey-zone surrounding the teaching and use of the DPL. The objectives of this article are to briefly review the recent literature, to analyze the patterns in the use of the DPL in Canada, and to determine whether general surgery residents are being taught the skill.

Methods

Literature review was conducted using PubMed and Ovid. The Canadian Institute for Health Information (CIHI) supplied the available data on DPL usage in Canada. General surgery program directors in Canada were contacted by e-mail to determine if the DPL was still being taught.

Results

Between the years of 2001 and 2006 in Canada, 38 DPLs were coded into the CIHI's database. Males accounted for 84.2% of the DPLs, and 23.7% of all DPLs resulted in a laparotomy. Motor vehicle crashes were the reason that 42% of the DPLs were performed. The majority of general surgery residency programs in Canada are not teaching the DPL outside of what is taught in the advanced trauma life support (ATLS) course.

Discussion

The literature reviewed shows that the DPL continues to play a role in the current management of patients suffering from both blunt and penetrating trauma, although a much more limited role than in the past.

How to cite this article

Boone D, Clarkson CA. The Diagnostic Peritoneal Lavage: A Brief Review of the Current Literature and an Analysis of Its use and Teaching in Canada. Panam J Trauma Critical Care Emerg Surg 2012;1(3):150-153.
A robust calibration approach for PM10 prediction from MODIS aerosol optical depth
Authors: Yap X. Q. , Hashim M.
Published: March 2013

Abstract. Investigating the human health effects of atmospheric particulate matter (PM) using satellite data are gaining more attention due to their wide spatial coverage and temporal advantages. Such epidemiological studies are, however, susceptible to bias errors and resulted in poor predictive output in some locations. Current methods calibrate aerosol optical depth (AOD) retrieved from MODIS to further predict PM. The recent satellite-based AOD calibration uses a mixed effects model to predict location-specific PM on a daily basis. The shortcomings of this daily AOD calibration are for areas of high probability of persistent cloud cover throughout the year such as in the humid tropical region along the equatorial belt. Contaminated pixels due to clouds causes radiometric errors in the MODIS AOD, thus causes poor predictive power on air quality. In contrary, a periodic assessment is more practical and robust especially in minimizing these cloud-related contaminations. In this paper, a simple yet robust calibration approach based on monthly AOD period is presented. We adopted the statistical fitting method with the adjustment technique to improve the predictive power of MODIS AOD. The adjustment was made based on the long-term observation (2001–2006) of PM10-AOD residual error characteristic. Furthermore, we also incorporated the ground PM measurement into the model as a weighting to reduce the bias of the MODIS-derived AOD value. Results indicated that this robust approach with monthly AOD calibration reported an improved average accuracy of PM10 retrieval from MODIS data by 50% compared to widely used calibration methods based on linear regression models, in addition to enabling further spatial patterns of periodic PM exposure to be undertaken.
The CM SAF SSM/I-based total column water vapour climate data record: methods and evaluation against re-analyses and satellite
Authors: Schröder M. , Jonas M. , Lindau R. , Schulz J. , Fennig K.
Published: March 2013

Abstract. The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring (CM SAF) aims at the provision and sound validation of well documented Climate Data Records (CDRs) in sustained and operational environments. In this study, a total column water vapour path (WVPA) climatology from CM SAF is presented and inter-compared to water vapour data records from various data sources. Based on homogenised brightness temperatures from the Special Sensor Microwave Imager (SSM/I), a climatology of WVPA has been generated within the Hamburg Ocean–Atmosphere Fluxes and Parameters from Satellite (HOAPS) framework. Within a research and operation transition activity the HOAPS data and operation capabilities have been successfully transferred to the CM SAF where the complete HOAPS data and processing schemes are hosted in an operational environment. An objective analysis for interpolation, namely kriging, has been applied to the swath-based WVPA retrievals from the HOAPS data set. The resulting climatology consists of daily and monthly mean fields of WVPA over the global ice-free ocean. The temporal coverage ranges from July 1987 to August 2006. After a comparison to the precursor product the CM SAF SSM/I-based climatology has been comprehensively compared to different types of meteorological analyses from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA40, ERA INTERIM and operational analyses) and from the Japan Meteorological Agency (JMA–JRA). This inter-comparison shows an overall good agreement between the climatology and the analyses, with daily absolute biases generally smaller than 2 kg m−2. The absolute value of the bias to JRA and ERA INTERIM is typically smaller than 0.5 kg m−2. For the period 1991–2006, the root mean square error (RMSE) for both reanalyses is approximately 2 kg m−2. As SSM/I WVPA and radiances are assimilated into JMA and all ECMWF analyses and to assess consistency with existing WVPA climatologies, the SSM/I-based climatology is also compared to the time series of SSM/I and TMI (Tropical Rainfall Measuring Mission Microwave Imager) WVPA from Remote Sensing Systems (RSS), leading to results consistent with the reanalyses results. This evaluation study gives confidence in consistency, accurateness and stability of the total water vapour climatology produced.
Jena Reference Air Set (JRAS): a multi-point scale anchor for isotope measurements of CO2 in air
Authors: Wendeberg M. , Richter J. M. , Rothe M. , Brand W. A.
Published: March 2013

Abstract. The need for a unifying scale anchor for isotopes of CO2 in air was brought to light at the 11th WMO/IAEA Meeting of Experts on Carbon Dioxide in Tokyo 2001. During discussions about persistent discrepancies in isotope measurements between the worlds leading laboratories, it was concluded that a unifying scale anchor for Vienna Pee Dee Belemnite (VPDB) of CO2 in air was desperately needed. Ten years later, at the 2011 Meeting of Experts on Carbon Dioxide in Wellington, it was recommended that the Jena Reference Air Set (JRAS) become the official scale anchor for isotope measurements of CO2 in air (Brailsford, 2012). The source of CO2 used for JRAS is two calcites. After releasing CO2 by reaction with phosphoric acid, the gases are mixed into CO2-free air. This procedure ensures both isotopic stability and longevity of the CO2. That the reference CO2 is generated from calcites and supplied as an air mixture is unique to JRAS. This is made to ensure that any measurement bias arising from the extraction procedure is eliminated. As every laboratory has its own procedure for extracting the CO2, this is of paramount importance if the local scales are to be unified with a common anchor. For a period of four years, JRAS has been evaluated through the IMECC1 program, which made it possible to distribute sets of JRAS gases to 13 laboratories worldwide. A summary of data from the six laboratories that have reported the full set of results is given here along with a description of the production and maintenance of the JRAS scale anchors. 1 IMECC refers to the EU project "Infrastructure for Measurements of the European Carbon Cycle" (http://imecc.ipsl.jussieu.fr/).
Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis
Authors: Tolosa I. , Fiorini S. , Gasser B. , Martín J. , Miquel J. C.
Published: March 2013

Abstract. Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound-specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean) were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C3 terrestrial plants, bacterial and zooplankton material in the organic matter (OM) of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C3 terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and <1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (>80%), with a minor contribution of fossil and C3 terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C3 terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%), whereas those from the slope contained the highest proportion of fossil (40%) and C3 terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low compared to other studies conducted 5–20 yr earlier, and they support the increase in primary production during the last decade mainly because of the increase in the number of ice-free days and due to the strength and persistence of winds favouring upwelling.
Baseline characteristics of climate, permafrost and land cover from a new permafrost observatory in the Lena River Delta, Siberia (1998–2011)
Authors: Boike J. , Kattenstroth B. , Abramova K. , Bornemann N. , Chetverova A. , Fedorova I. , Fröb K. , Grigoriev M. , Grüber M. , Kutzbach L. , Langer M. , Minke M. , Muster S. , Piel K. , Pfeiffer E.-M. , Stoof G. , Westermann S. , Wischnewski K. , Wille C. , Hubberten H.-W.
Published: March 2013

Abstract. Samoylov Island is centrally located within the Lena River Delta at 72° N, 126° E and lies within the Siberian zone of continuous permafrost. The landscape on Samoylov Island consists mainly of late Holocene river terraces with polygonal tundra, ponds and lakes, and an active floodplain. The island has been the focus of numerous multidisciplinary studies since 1993, which have focused on climate, land cover, ecology, hydrology, permafrost and limnology. This paper aims to provide a framework for future studies by describing the characteristics of the island's meteorological parameters (temperature, radiation and snow cover), soil temperature, and soil moisture. The land surface characteristics have been described using high resolution aerial images in combination with data from ground-based observations. Of note is that deeper permafrost temperatures have increased between 0.3 to 1.3 °C over the last five years. However, no clear warming of air and active layer temperatures is detected since 1998, though winter air temperatures during recent years have not been as cold as in earlier years. Data related to this article are archived under: http://doi.pangaea.de/10.1594/PANGAEA.806233.
Seasonal changes in photochemical properties of dissolved organic matter
Authors: Porcal P. , Dillon P. J. , Molot L. A.
Published: March 2013

Abstract. The fate of dissolved organic matter (DOM) in lakes and streams is significantly affected by photochemical transformation of DOM. A series of laboratory photochemical experiments was conducted to describe long-term changes in photochemical properties of DOM. The stream samples used in this study originated from three different catchments on the southern-most part of the Boreal ecozone near Dorset, Ontario, Canada. A first-order kinetics equation was used to model photochemical degradation of DOM and the kinetic rate constant, K, was used as an indicator of photochemical properties of DOM. Highest Kwas observed in samples from the catchment dominated by coniferous forest while the lowest K was measured in the deciduous catchment. Kinetic rate constants from all three catchments showed a sinusoidal pattern during the hydrological year. K increased steadily during autumn and winter and decreased during spring and summer. The highest values were observed during spring melt events when DOM was flushed from terrestrial sources by high flows. The minimum rate constants were found in summer when discharge was lowest. DOM molecular weight and specific absorbance at 254 nm also exhibited annual cycles corresponding to the seasonal cycles of terrestrial organic matter but the relationships between these properties and K was probably affected by previous exposure to solar radiation during transit from the catchment as well as pH and iron.
Stable isotope record of Eemian seasonal temperature from MIS 5e tufa stromatolite; Somme Basin, Northern France
Authors: Dabkowski J. , Andrews J. , Antoine P. , Marca-Bell A.
Published: March 2013

Abstract. In many modern to sub-fossil deposits tufa formations, very well crystallised deposits called stromatolites are preserved. These are often strongly laminated deposits, the laminae linked to seasonal climatic and environmental variations. Where found in fossil tufas such deposits have huge potential as high resolution archives of Pleistocene climate. One of the first investigations of this type has been performed on a 2.5 cm-radius stromatolite from the Eemian sequence of Caours (Somme Basin, Northern France), where precise observations in thin section have been combined with intra-lamina δ18O and δ13C analyses. Independent interpretations of petrographical and geochemical data are strongly coherent and demonstrate a clear seasonal signal. Moreover, as δ18O is temperature dependent, we have quantified likely maximum water temperature variations between summer and winter at Caours. A small mismatch between the δ18O derived temperature values and the typical modern range is observed, which may reflect a real difference between modern and Eemian temperature seasonality. This study supports previous investigations performed on a laminated tufa from central Greece and clearly confirms the potential of tufa stromatolites as records of seasonal climatic information and for the quantification of riverine water temperature variations.
LAPM: a tool for underwater Large-Area Photo-Mosaicking
Authors: Marcon Y. , Sahling H. , Bohrmann G.
Published: March 2013

Abstract. This paper presents a new tool for large-area photo-mosaicking (LAPM tool). This tool was developed specifically for the purpose of underwater mosaicking, and it is aimed at providing end-user scientists with an easy and robust way to construct large photo-mosaics from any set of images. It is notably capable of constructing mosaics with unlimited amount of images and on any recent computer. The mosaicking process can rely on both feature matching and navigation data. This is complemented by an intuitive graphical user interface, which gives the user full control over the feature matches between any pair of overlapping images. Finally, mosaic files are given geographic attributes that allow direct import into ArcGIS. So far, the LAPM tool was successfully used to construct geo-referenced photo-mosaics with photo and video material from several scientific cruises. The largest photo-mosaic contained more than 5000 images for a total area of about 105 000 m2.
An experimental study of pyroxene crystallization during rapid cooling in a thermal gradient; applications to komatiites and chondrites
Authors: Bouquain S. , Arndt N. T. , Faure F. , Libourel G.
Published: March 2013

Abstract. To investigate the crystallization of pyroxene in spinifex-textured komatiites and in chondrites we undertook a series of experiments in which compositions in the CMAS system were cooling rapidly in a thermal gradient. Cooling rates were generally between 5 to 10 °C h−1 but some runs were made at 100–200 °C h−1; thermal gradients were between 10 and 20 °C cm−1. These conditions reproduced those at various levels in the crust of komatiitic lava flow. The starting composition was chosen to have pigeonite on the liquidus and a majority of the experiments crystallized zoned pigeonite-diopside crystals like those in komatiite lavas. A~conspicuous aspect of the experimental results was their lack of reproduceability. Some experiments crystallized forsterite whereas others that were run under similar conditions crystallized two pyroxenes and no forsterite; some experiments were totally glassy but others totally crystallized to pyroxene. The degree of supercooling at the onset of pyroxene crystallization was variable, from less than 25 °C to more than 110 °C. We attribute these results to the difficulty of nucleation of pyroxene. In some cases forsterite crystallized metastably and modified the liquid composition to inhibit pyroxene crystallization; in others no nucleation took place until a large degree of supercooling was achieved, then pyroxene crystallized rapidly. Pigeonite crystallized under a wide range of conditions, at cooling rates from 3 to 100 °C h−1. The notion that this mineral only forms at low cooling rates is not correct.
Mechanisms causing reduced Arctic sea ice loss in a coupled climate model
Authors: West A. E. , Keen A. B. , Hewitt H. T.
Published: March 2013

Abstract. The fully coupled climate model HadGEM1 produces one of the most accurate simulations of the historical record of Arctic sea ice seen in the IPCC AR4 multi-model ensemble. In this study, we examine projections of sea ice decline out to 2030, produced by two ensembles of HadGEM1 with natural and anthropogenic forcings included. These ensembles project a significant slowing of the rate of ice loss to occur after 2010, with some integrations even simulating a small increase in ice area. We use an energy budget of the Arctic to examine the causes of this slowdown. A negative feedback effect by which rapid reductions in ice thickness north of Greenland reduce ice export is found to play a major role. A slight reduction in ocean-to-ice heat flux in the relevant period, caused by changes in the meridional overturning circulation (MOC) and subpolar gyre in some integrations, as well as freshening of the mixed layer driven by causes other than ice melt, is also found to play a part. Finally, we assess the likelihood of a slowdown occurring in the real world due to these causes.
Clinical Insight into the Precaval Right Renal Artery: A Multidetector Row Computed Tomography Angiographic Study
Authors: Srivastava Shubha , Kumar Indra , Babu C. S. Ramesh , Gupta K. K. , Gupta O. P.
Published: March 2013

Variations of course and number of renal vessels are not so uncommon and their knowledge is important for planning of minimally invasive renal surgeries. The earlier literature reports a prevalence of precaval right renal artery between 0.8% and 5%. Normally, the right renal artery passes posterior to the inferior vena cava, but it can also be precaval where it passes anterior to inferior vena cava. The multidetector row contrast enhanced computed tomography angiography allows precise evaluation of renal vasculature. The aim of this retrospective study is to determine the prevalence of precaval right renal artery. Amongst 73 MDCT scans studied, we identified 4 cases of precaval right renal artery with the prevalence being 5.48%, more than what is reported in the earlier literature. We also report a single and dominant precaval right renal artery in one of the cases, which is a rare finding. On the basis of these results, we conclude that precaval right renal artery appears to be more common and so the knowledge of this variant holds a major clinical implication in preventing misinterpretation of radiological images and proper planning of interventional procedures and minimally invasive surgeries.
My patient is thrombocytopenic! Is (s)he? Why? And what shall I do?
Authors: Alberio L.
Published: March 2013

Solving the riddle of a thrombocytopenic patient is a difficult and fascinating task. The spectrum of possible aetiologies is wide, ranging from an in vitro artefact to severe treatment-resistant thrombocytopenic bleeding conditions, or even life-threatening prothrombotic states. Moreover, thrombocytopenia by itself does not protect from thrombosis and sometimes a patient with a low platelet count requires concomitant antithrombotic treatment as well. In order to identify and treat the cause and the effects of the thrombocytopenia, you have to put together several pieces of information, solving a unique jig-jaw puzzle.

The present work is not a textbook article about thrombocytopenia, rather a collection of differential diagnostic thoughts, treatment concepts, and some basic knowledge, that you can retrieve when facing your next thrombocytopenic patient. Enjoy reading it, but most importantly enjoy taking care of patients with a low platelet count. I bet the present work will assist you in this challenging and rewarding clinical task.
Myeloid Sarcoma of the Head and Neck Region
Authors: Zhou Jane , Bell Diana , Medeiros L. Jeffrey
Published: March 2013

Context.—Myeloid sarcoma of the head and neck region can pose diagnostic challenges because of the low frequency of myeloid sarcoma and the potential for tumors of almost any lineage to occur in the head and neck.

Objective.—To study the clinicopathologic and immunohistochemical characteristics of myeloid sarcoma in the head and neck region and to review the differential diagnosis.

Design.—We searched for cases of myeloid sarcoma involving the head and neck region for a 24-year period at our institution. The medical records and pathology slides were reviewed. Additional immunohistochemical stains were performed.

Results.—We identified 17 patients, age 17 to 85 years. Most tumors involved the oral cavity. Myeloid sarcoma was the initial diagnosis in 9 patients (53%); the remaining 8 patients (47%) had a history of bone marrow disease. Immunohistochemical analysis using antibodies specific for lysozyme, CD43, and CD68 were highly sensitive for diagnosis but were not specific. By contrast, assessment for myeloperoxidase in this study was less sensitive but more specific. We also used antibodies specific for CD11c and CD33 in a subset of cases, and these reagents seem helpful as well.

Conclusions.—The clinical presentation of myeloid sarcoma involving the head and neck, particularly the mouth, is often nonspecific, and a high degree of suspicion for the possibility of myeloid sarcoma is needed. Immunohistochemistry is very helpful for establishing the diagnosis.
The Effects of Legal and Extralegal Factors on Probation Revocation Decisions
Authors: Verrecchia P.J. , Ling Eric
Published: March 2013

Abstract: This study attempts to further the understanding of how legal and extra legal factors affect the decision of criminal justice professionals, specifically, adult probation officers. The findings show that while both legal and extra legal factors were significant in the decision to revoke probation and the length of the sentence, the factors were different for each decision.
Mental Health, Welfare Reliance, and Lone Motherhood
Authors: Caragata Lea , Liegghio Maria
Published: March 2013

This paper explores the life circumstances and mental health experiences of welfare-reliant lone mothers, utilizing data from the Lone Mothers: Building Social Inclusion project, a Canada-wide research program. On the basis of qualitative interviews conducted with 43 welfare-reliant lone mothers living in Toronto, Ontario, we examine the conditions of their lives and the ways in which mental health, poverty, and single motherhood intersect. These intersections reveal the problematic nature of the traditional mental health system's response to these women. Required is a broader understanding of the ways that impoverished lone mothers’ mental health is structurally situated, and requires population-based rather than individualized responses.
Are Mantle Plumes Periodic?
Authors: Rampino Michael R. , Prokoph Andreas
Published: March 2013

In the past few years, researchers have uncovered evidence that several kinds of geological and biological events seem to show regular cycles of similar lengths. For example, Rohde and Muller [2005] looked at the record of diversity of marine organisms over the past 540 million years and found evidence for two cycles in the data—a roughly 62‐million‐year cycle and a longer cycle of about 140 million years. This was followed by reports of an approximately 56‐million‐year cycle in long‐term stratigraphic sequences in sedimentary basins [Meyers and Peters, 2011] and a 59‐million‐year period in the marine strontium‐isotope record [Melott et al., 2012]. A similar period may even exist in atmospheric carbon dioxide over the past 542 million years of the Phanerozoic [Franks et al., 2012]. A cycle of about 140 million years was reported by Veizer et al. [2000] and Mayhew et al. [2008] in long‐term fluctuations in global climate.
National Medal of Science nominations sought
Authors: Showstack Randy
Published: March 2013

The U.S. National Science Foundation (NSF) is accepting nominations for the 2013 National Medal of Science until 1 April 2013. Congress established the medal in 1959 as a presidential award for individuals “deserving of special recognition by reason of their outstanding contributions to knowledge in the physical, biological, mathematical, or engineering sciences.” Later, Congress expanded the recognition to include the social and behavioral sciences. NSF notes, “We are especially interested in identifying women, members of minority groups, and persons with disabilities for consideration.” More information is available at http://www.nsf.gov/od/nms/medal.jsp and http://www.nsf.gov/od/nms/nsf_2013nationalmedalofscience_callfornominations.pdf. For more details, contact the Medal of Science program manager at nms@nsf.gov or 703‐292‐8040.
Climate Scientists Take To the Hill
Authors: McLaughlin Rachel
Published: March 2013

On 27 February 2013 amid hearings and talk of the looming across‐the‐board budget cuts known as sequestration, AGU partnered with 16 other scientific societies to bring 50 scientists studying different aspects of climate change to Washington, D. C., for the third annual Climate Science Congressional Visits Day on Capitol Hill. Representing a wide array of expertise, from meteorology to public health, paleoclimatology to agriculture, the scientists came to speak to members of Congress on the realities of climate change.
A Climate Science Day Participant Describes the Experience
Authors: Cobb Kim
Published: March 2013

As a paleoclimate scientist, I was thrilled to take part in the third annual Climate Science Day on Capitol Hill. The associated training was substantive and engaging and focused on helping us be heard through the din on the Hill. While my prior experiences with Hill visits have tempered my hopes for effecting lasting change, I believe that such conversations help put a face on climate science.
Assessing the latest models' handling of climate extremes
Authors: Schultz Colin
Published: March 2013

In time for the slated September release by the Intergovernmental Panel on Climate Change of its fifth assessment report, Sillmann et al. conducted an assessment of the latest generation of global climate models and historical reanalysis datasets. The authors did not set about comparing the ability of the models and reanalyses to represent climate means and norms but, instead, focused on the models' skill in generating temperature and precipitation extremes similar to those that have been observed. As part of the fifth phase of the Coupled Model Intercomparison Project (CMIP5), the authors looked at 31 global models and 4 reanalysis datasets. To determine the models' skill, the scientists compared their representations of climate extremes against the observational dataset HadEX2. To gauge progress over earlier models, they also looked at the 18 models that made up the 3rd phase of the CMIP.
Electron Transport at the Nanometer‐Scale Spatially Revealed by Four‐Probe Scanning Tunneling Microscopy
Authors: Li An‐Ping , Clark Kendal W. , Zhang X.‐G. , Baddorf Arthur P.
Published: March 2013

Electron transport at the nanometer‐scale is the key to novel applications of nanomaterials in electronic and energy technologies. Due to the restricted dimensionality, one of the distinctive characteristics of nano‐systems is their transport properties critically depend on structural details. Therefore, an important requirement for transport research of a specific nanomaterial system is to examine structures and properties in a coherent manner. In this regard, four‐probe scanning tunneling microscopy (STM), which combines four independently controllable STMs with a scanning electron microscope (SEM) in the same cryogenic environment, is uniquely useful for probing electron transport on multiple length‐scales and revealing how transport is coupled to the electronic and structural properties down to the atomic scale for individual nanomaterials. By utilizing this unique tool, extensive research has been undertaken to explore aspects of nanotransport, which include (a) intertwined electronic and structural phase transitions in surface supported two‐dimensional structures, (b) effects of atomic defects and interwire coupling on the electronic and transport properties of ultra thin quantum wire systems, (c) grain boundary resistances in copper nanowires with one‐to‐one correspondence to the grain boundary structure, (d) defect scattering effects in two‐dimensional electron gas systems, and (e) evaluation of transport behaviors of individual semiconductor nano‐junctions and nanodevices. In this paper, transport measurement techniques are first introduced with a four‐probe STM and then the recent progress on its applications is reviewed with a focus on the spatially resolved electron transport at the nanometer‐scale. The goal is to stimulate further advancement and utilization of techniques capable of characterizing materials properties at the nanometer‐scale to facilitate the exploration of the great promise of nanoscience and nanotechnology.
Life Beyond Diffraction: Opening New Routes to Materials Characterization with Next‐Generation Optical Near‐Field Approaches
Authors: Schuck P. James , Weber‐Bargioni Alexander , Ashby Paul D. , Ogletree D. Frank , Schwartzberg Adam , Cabrini Stefano
Published: March 2013

Near‐field optical microscopies and spectroscopies seek to investigate materials by combining the best aspects of optical characterization and scan‐probe microscopy techniques. In principle, this provides access to chemical, morphological, physical and dynamical information at nanometer length scales that is impossible to access by other means. But a number of challenges, particularly on the scan‐probe front, have limited the widespread application of near‐field investigations. This work describes how recent probe engineering and technique innovation have addressed many of these challenges. This Feature Article begins with a short overview of the field, providing perspective and motivation for these developments and highlighting some key improvements. This is followed by a more in‐depth description of the near‐field advances developed at the Molecular Foundry, a national nanoscience User Facility–advances that provide groundwork for generally‐applicable nano‐optical studies. Finally, a discussion is provided of what progress is still needed in order to realize the ultimate objective of translating all optical measurements to the nanoscale.
Interface Recombination in Depleted Heterojunction Photovoltaics based on Colloidal Quantum Dots
Authors: Kemp Kyle W. , Labelle Andre J. , Thon Susanna M. , Ip Alexander H. , Kramer Illan J. , Hoogland Sjoerd , Sargent Edward H.
Published: March 2013

Interface recombination was studied in colloidal quantum dot photovoltaics. Optimization of the TiO2‐PbS interface culminated in the introduction of a thin ZnO buffer layer deposited with atomic layer deposition. Transient photovoltage measurements indicated a nearly two‐fold decrease in the recombination rate around 1 sun operating conditions. Improvement to the recombination rate led to a device architecture with superior open circuit voltage (VOC) and photocurrent extraction. Overall a 10% improvement in device efficiency was achieved with Voc enhancements up to 50 mV being realized.
A Stochastic Optimization approach for the design of Individualized Dosage Regimens
Authors: Laínez‐Aguirre José M. , Reklaitis Gintaras V.
Published: March 2013

Quantitative methods for individualizing and optimizing the dosage regimen and clinically monitoring each patient are desirable to insure that each patient can obtain effective therapeutic benefit while minimizing undesirable side effects. This is of special concern for medicines that are expensive or whose toxic side effects are severe (e.g., oncological agents). The optimal dosage regimen for an individual is a combination of dose amount and/or dosing interval (i.e., time between doses) which minimizes the risk that the drug exposure deviates from the desired therapeutic window. The therapeutic window is defined as the range of drug exposure (e.g., blood concentration, area under the curve concentration‐time) which is below a threshold defining an acceptable toxic side effect and above a threshold defining a minimum acceptable level of therapeutic efficacy. In this work, the dosage regimen optimization problem defined in terms of general pharmacometric models (i.e., described by differential‐algebraic equations) is presented and a solution approach outlined which uses a scenario‐based stochastic optimization formulation that minimizes a risk metric. The scenarios are derived from the posterior joint probability distribution of the individual's pharmacometric parameters which is obtained following an approximate Bayesian inference approach. A Smolyak rule is used for the selection of the scenarios (i.e., combination of pharmacometric parameters) to be considered and for computing the approximation to the risk metric. Two case studies, gabapentin and cyclophosphamide, are presented to elucidate the advantages and limitations of the proposed approach. The numerical results demonstrate that low risk optimal solutions can be generated via the proposed stochastic optimization; while significantly reducing the computational burden in comparison with the conventional Markov chain Monte Carlo—grid search approach. This partially alleviates implementation issues preventing the deployment of dosage regimen individualization in clinical practice. Since stochastic optimization has been extensively used in other domains, the approach for uncertainty characterization proposed in this work may have general relevance beyond the pharmacometrics domain. © 2013 American Institute of Chemical EngineersAIChE J, 59: 3296–3307, 2013
A composite equation of state for the modeling of sonic carbon dioxide jets in carbon capture and storage scenarios
Authors: Wareing Christopher J. , Woolley Robert M. , Fairweather Michael , Falle Samuel A. E. G.
Published: March 2013

The development of a novel composite two‐phase method to predict the thermodynamic physical properties of carbon dioxide (CO2) above and below the triple point, applied herein in the context of Reynolds‐Averaged Navier–Stokes computational modeling has been detailed here. A number of approaches have been combined to make accurate predictions in all three phases (solid, liquid, and gas) and at all phase changes for application in the modeling of releases of CO2 at high pressure into the atmosphere. Predictions of a free release of CO2 into the atmosphere from a reservoir at a pressure of 10 MPa and a temperature of 283 K, typical of transport conditions in carbon capture and storage scenarios, is examined. A comparison of the results shows that the sonic CO2 jet that forms requires a three‐phase equation of state including the latent heat of fusion to realistically simulate its characteristics. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3928–3942, 2013
Model‐based risk analysis of coupled process steps
Authors: Westerberg Karin , Broberg‐Hansen Ernst , Sejergaard Lars , Nilsson Bernt
Published: March 2013

A section of a biopharmaceutical manufacturing process involving the enzymatic coupling of a polymer to a therapeutic protein was characterized with regards to the process parameter sensitivity and design space. To minimize the formation of unwanted by‐products in the enzymatic reaction, the substrate was added in small amounts and unreacted protein was separated using size‐exclusion chromatography (SEC) and recycled to the reactor. The quality of the final recovered product was thus a result of the conditions in both the reactor and the SEC, and a design space had to be established for both processes together. This was achieved by developing mechanistic models of the reaction and SEC steps, establishing the causal links between process conditions and product quality. Model analysis was used to complement the qualitative risk assessment, and design space and critical process parameters were identified. The simulation results gave an experimental plan focusing on the “worst‐case regions” in terms of product quality and yield. In this way, the experiments could be used to verify both the suggested process and the model results. This work demonstrates the necessary steps of model‐assisted process analysis, from model development through experimental verification. Biotechnol. Bioeng. 2013; 110:2462–2470. © 2013 Wiley Periodicals, Inc.
Development and validation of dried blood spots technique for quantitative determination of topiramate using liquid chromatography–tandem mass spectrometry
Authors: Vnučec Popov Tanja , Maričič Lea Cvitkovič , Prosen Helena , Vončina Darinka Brodnjak
Published: March 2013

An LC‐MS/MS method for determination of the anti‐epileptic drug topiramate (TPM) in dried blood spot (DBS) samples was developed and validated. DBS samples were prepared by spotting 30 μL of spiked whole blood onto FTATM DMPK‐C cards and drying for at least 3 h. Six‐millimetre punched spots were then extracted by using a mixture of methanol and water (90:10, v/v) with deuterated internal standard (topiramate‐d12). The extracted samples were injected into a liquid chromatograph equipped with a tandem mass spectrometric detector. Negative ions were monitored in the selected reaction monitoring mode and transitions m/z 338.2 → 78.1 and m/z 350.3 → 78.1 were used for the quantitative evaluation of TPM and internal standard, respectively. The results obtained from validation were statistically evaluated according to the requirements of the European Medicines Agency and US Food and Drug Administration regulatory guidelines. The linearity of the method was checked within a concentration range from 10 to 2000 ng/mL. The validation results indicate that the method is accurate, precise, sensitive, selective and reproducible. Copyright © 2013 John Wiley & Sons, Ltd.
Prognostic impact and the relevance of PTEN copy number alterations in patients with advanced colorectal cancer (CRC) receiving bevacizumab
Authors: Price Timothy J. , Hardingham Jennifer E. , Lee Chee K. , Townsend Amanda R. , Wrin Joseph W. , Wilson Kate , Weickhardt Andrew , Simes Robert J. , Murone Carmel , Tebbutt Niall C.
Published: March 2013

Loss of phosphatase and tensin homologue (PTEN) expression may be prognostic in colorectal cancer (CRC) and may have a correlation with vascular endothelial growth factor (VEGF) expression via hypoxia‐inducible factor 1 (HIF‐1) alpha, and the PI3K/mTOR pathways. We therefore have explored the prognostic association of PTEN loss and the potential that PTEN loss may be predictive of outcome with bevacizumab. Patients enrolled in the AGITG MAX trial, a randomized Phase III trial of capecitabine (C) +/− bevacizumab (B) (+/− mitomycin C [M]) with available tissues were analyzed for PTEN expression (loss vs. no loss) as assessed using a Taqman® copy number assay (CNA). Of the original 471 patients enrolled, tissues from 302 (64.1%) patients were analyzed. PTEN loss was observed in 38.7% of patients. There was no relationship between PTEN loss and KRAS or BRAF mutation. PTEN status was not prognostic for progression‐free survival (PFS) or overall survival (OS) in multivariate analyses adjusting for other baseline factors; loss versus no loss PFS hazard ratio (HR) 0.9 (0.7–1.16), OS HR 1.04 (0.79–1.38). PTEN was not prognostic when assessed by KRAS and BRAF status. By using the comparison of C versus CB+CBM, PTEN status was not significantly predictive of the effectiveness of B for PFS or OS. PTEN status was not prognostic for survival in advanced colorectal cancer, irrespective of KRAS or BRAF status. PTEN status did not significantly predict different benefit with bevacizumb therapy.
Bifurcation stenting in patients with ST‐Segment elevation myocardial infarction
Authors: Kwan Tak W. , Gujja Karthik , Liou Michael C. , Huang Yili , Wong Sally , Coppola John , Chen Shao‐Liang
Published: March 2013

Objective

We sought to study the clinical outcomes of bifurcation stenting in patients who presented with stent thrombosis segment elevation myocardial infarction (STEMI).

Background

Patients with STEMI are usually excluded from randomized bifurcation studies. There is limited information for bifurcation stenting in this population.

Methods

All STEMI patients who were randomized were retrospectively reviewed from DKCRUSH II (double kissing, double crush) database. DKCRUSH II is a multicenter, randomized study of provisional stenting (PS) versus the DK crush stenting techniques. A total of 370 patients with bifurcation lesions were randomized and of this group a total of 63 patients with STEMI were found. This group of STEMI included 30 patients in the PS group and 33 patients in the DK crush stenting group.

Results

There were no differences in terms of contrast used, procedure time, and fluoroscopy time. Procedural success rates were 97% in all patients with STEMI, with 100% in the PS group and 94% in the DK crush stenting group. During the procedure, there were two patients with less than TIMI 3 (thrombolysis in myocardial infarction) flow in the main vessel of the DK crush group However, TIMI 3 flow was 100% in the side branch for both groups. Cumulative 12‐month major adverse cardiac event (MACE) was 22% in the whole STEMI group, whereas PS and DK crush groups were 23% versus 21%, respectively (P = NS). There were no differences in in‐hospital, 6‐month, and 12‐month MACE in these two groups. At 6 and 12 months, there were two cardiac deaths in the PS group but without statistical significance when compared with the DK crush stenting group (7% vs. 0%, P = NS).

Conclusion

Bifurcation stenting in patients with STEMI is safe and feasible. The immediate and midterm clinical outcomes were comparable between PS and DK crush stenting. © 2013 Wiley Periodicals, Inc.
Computational Fluid Dynamics Simulation of Mass Transfer in the Separation of Fermentation Products Using Nanoporous Membranes
Authors: Ranjbar M. , Shirazian S. , Ghafarnejad Parto S. , Ahmadi M.
Published: March 2013

The simulation of fermentation product separation using nanoporous membranes is presented. The aim of the simulation was to predict the performance of an extraction process to remove compounds from aqueous solutions. The simulation was conducted using computational fluid dynamics techniques for the solution of governing equations. The system studied was a membrane‐based extractor of acetone from aqueous solutions using near‐critical CO2 as solvent. The predicted extraction percentages obtained by the simulations were compared to experimental values reported in the literature and showed very good agreement. The simulation can predict the concentration profile of acetone in the membrane and also predicts the formation of a concentration boundary layer.
O‐Heterocyclic Embeurekols from Embellisia eureka, an Endophyte of Cladanthus arabicus
Authors: Ebrahim Weaam , Aly Amal H. , Mándi Attila , Wray Victor , Essassi El Mokhtar , Ouchbani Tarik , Bouhfid Rachid , Lin Wenhan , Proksch Peter , Kurtán Tibor , Debbab Abdessamad
Published: March 2013

Three new polyketides (-)-1, (+)-1, and 2) were isolated from the EtOAc extract of the fungus Embellisia eureka, an endophyte of the Moroccan plant Cladanthus arabicus (Asteraceae). The structures of these new compounds were determined on the basis of one‐ and two‐dimensional NMR spectroscopy as well as by high‐resolution mass spectrometry. The absolute configurations of (-)-1, (+)-1, and 2 were determined by TDDFT ECD calculations of solution conformers, online HPLC‐ECD analysis, and the modified Mosher method. Chirality 25:250–256, 2013. © 2013 Wiley Periodicals, Inc.
Enhancement of the liquid feed distribution in gas solid fluidised beds by non‐mechanically induced nozzle pulsations
Authors: Sabouni Rana , Briens Cedric , Berruti Franco
Published: March 2013

The effect of non‐mechanically induced nozzle pulsations was investigated in the current work, and it was found that appropriately tailored spray nozzles pulsations resulted in the dramatic improvement of the liquid feed spray distribution on particles of a fluidised bed. Non‐mechanically induced pulsations were imposed on the liquid spray, using liquid and gas circuits that favour the development of beneficial pulsations. The resulting effect on liquid dispersion on the fluidised bed particles was determined with a conductance method. © 2013 Canadian Society for Chemical Engineering