bluuebunny/crossref_metadata_2025 huggingface dataset:
The history of veterinary medicine in Namibia
Authors: Schneider Herbert P.
Published: May 2012

Until the middle of the 19th century, very few references exist regarding the occurrence of animal diseases in Namibia. With the introduction of contagious bovine pleuropneumonia (CBPP) in 1859, this picture changed completely and livestock owners implemented various forms of disease control in an effort to contain the spread of this disease and minimise its devastating effects. After the establishment of the colonial administration in 1884, the first animal disease legislation was introduced in 1887 and the first veterinarian, Dr Wilhelm Rickmann, arrived in 1894. CBPP and the outbreak of rinderpest in 1897 necessitated a greatly expanded veterinary infrastructure and the first veterinary laboratory was erected at Gammams near Windhoek in 1897. To prevent the spread of rinderpest, a veterinary cordon line was established, which was the very beginning of the Veterinary Cordon Fence as it is known today. After the First World War, a small but dedicated corps of veterinarians again built up an efficient animal health service in the following decades, with veterinary private practice developing from the mid–1950s. The veterinary profession organised itself in 1947 in the form of a veterinary association and, in 1984, legislation was passed to regulate the veterinary profession by the establishment of the Veterinary Council of Namibia. The outbreak of foot and mouth disease in 1961 was instrumental in the creation of an effective veterinary service, meeting international veterinary standards of quality and performance which are still maintained today.
The nature and quality of the mathematical connections teachers make
Authors: Mhlolo Michael K. , Venkat Hamsa , Schäfer Marc
Published: May 2012

Current reforms in mathematics education emphasise the need for pedagogy because it offers learners opportunities to develop their proficiency with complex high-level cognitive processes. One has always associated the ability to make mathematical connections, together with the teacher’s role in teaching them, with deep mathematical understanding. This article examines the nature and quality of the mathematical connections that the teachers’ representations of those connections enabled or constrained. The researchers made video recordings of four Grade 11 teachers as they taught a series of five lessons on algebra-related topics. The results showed that the teachers’ representations of mathematical connections were either faulty or superficial in most cases. It compromised the learners’ opportunities for making meaningful mathematical connections. The researchers concluded by suggesting that helping teachers to build their representation repertoires could increase the effectiveness of their instructional practices.
Catéteres venosos centrales permanentes tunelizados para hemodiálisis: estudio de recirculación y dosis de diálisis con líneas normales e invertidas
Authors: Fernández Jiménez Antonio José , Aguilar Gómez Gustavo Samuel , Cabrera Plaza Irene , Moulín Martín Rocío , Marín Fábrega Virginia Asunción , Sánchez Orellana Tania , Marqués Racionero Mª José , Pérez Angulo Mª Dolores , Ortega Aranda Encarnación , Moya Ruiz Julia , Ortega Aranda Aurora , Perles Carracosa Gema , Morillo Pedregosa Mª Mercedes , Ramos Serrano Ana Mª , Sánchez Sánchez Luisa Mª
Published: May 2012

Introducción: Los Catéteres Venosos Centrales Permanentes Tunelizados para hemodiálisis presentan con frecuencia una complicación denominada efecto ventana o ventosa, en el que la rama arterial se colapsa en las maniobras de aspiración sin ofrecer resistencia al impeler, determinando la inversión de líneas para poder realizar el tratamiento.
El estudio se centra en la relación entre la posición anatómica de las puntas del catéter mediante radiografía de tórax y la recirculación medida con Dilución Ultrasónica, el Porcentaje de Reducción de Urea y el Kt/V, determinados tanto con líneas en posición normal e invertida y a flujos de bomba de 250 y 300 ml/min.
Material y método: Estudio Cuasiexperimental Intrasujeto de 18 meses de duración a n=28 catéteres implantados en 25 pacientes en Hemodiálisis.
Resultados:
• Recirculación:
• Líneas normales a 250 y 300 ml/min: 0,85 ± 2,41% y 1,23 ± 3,14%.
• Líneas invertidas a 250 y 300 ml/min; 22,41 ± 12,12% y 24,93 ± 12,09%.
• Porcentaje de Reducción de Urea:
• Líneas normales a 250 y 300 ml/min; 66,49 ± 8,62% y 70,55 ± 5,30%.
• Líneas invertidas a 250 y 300 ml/min; 61,05 ± 8,34% y 62,34 ± 8,68%.
• Kt/V:
• Líneas normales a 250 y 300 ml/min: 1,31 ± 0,30 y 1,46 ± 0,23%.
• Líneas invertidas a 250 y 300 ml/min: 1,10 ± 0,21% y 1,19 ± 0,30%.
Discusión: Los Porcentajes de Reducción de Urea y Kt/V con líneas invertidas a ambos flujos estudiados, manifiestan dosis de diálisis adecuadas asumiendo recirculaciones entorno al 20%.
Valoración de la eficacia de una pauta más lenta y frecuente en la administración de hierro intravenoso en pacientes en hemodiálisis durante un año
Authors: Brázalez Tejerina Mónica , Pérez Arranz Isabel , González-Parra Emilio , Pose Regueiro Nancy Mª , Muñoz Moreno Mª Fe
Published: May 2012

Uno de los problemas más frecuentes de los pacientes con enfermedad renal crónica (ERC) en hemodiálisis (HD) es la anemia, tratada habitualmente con factores estimuladores de la eritropoyesis. Esta estimulación requiere una mayor disponibilidad de los depósitos corporales de hierro (Fe)1. Para alcanzar los niveles que recomiendan las guías (Ferritina entre 200 y 400ng/ml - IST entre 30 y 40%) se administra hierro por vía intravenosa (Fe IV)2. Las pautas de administración varían en función de las necesidades de los pacientes, siendo habitual la infusión de 100mg de Fe sacarosa diluidos en 100cc de suero fisiológico semanal, quincenal o mensualmente3,4,5. Esta pauta de administración se realiza en los últimos 45 minutos de la sesión de HD, no estando establecida la velocidad ideal de perfusión de la dilución. Por ello, nos realizamos la pregunta de si la rapidez en la pauta de administración del hierro intravenoso podría influir en la eficacia del tratamiento, así como en la presentación de efectos adversos6. Para ello nos planteamos los siguientes objetivos: 1. Comparar la eficacia entre una pauta lenta y una pauta más frecuente y ultra lenta de administración de Fe IV, con respecto a los parámetros de la cinética del hierro, así como en los aportes de eritropoyetina y Fe que se realizaron. 2. Analizar si se originan menos efectos adversos por intolerancia con la administración de Fe IV con la pauta ultra lenta.
Gestación en paciente con tratamiento renal sustitutivo
Authors: Castellano Carrón Thais
Published: May 2012

La frecuencia de embarazo en mujeres sometidas a hemodiálisis es baja (entre 0,3 y 0,75% año mujeres en edad fértil)1. Este hecho se atribuye a diferentes factores hormonales, muchos de ellos anovulatorios: hiperprolactinemia, disfunción ovárica con anovulaciones, insuficiencia lútea, disminución de la libido (debido a alteraciones de los pulsos de la gonadotropina coriónica humana), niveles aumentados de leptina (por disminución de su aclaramiento renal), anormalidades del eje pituitario ovárico2. Cuando se produce un caso de embarazo en una paciente de HD, independientemente del criterio que se siga, la prescripción de la hemodiálisis debe ser suficiente para mantener estables las condiciones maternas en relación al volumen circulante, presión sanguínea (= 140/80 a 90 mm Hg 7,8,10) y la ganancia ponderal interdialítica. La prescripción de la ultrafiltración se debe individualizar para evitar episodios de hipovolemia, hipotensión arterial y arritmia cardiaca materna. Se debe ajustar para respetar la ganancia ponderal y la expansión del volumen sanguíneo materno que corresponde al tiempo de la gestación1. Los trastornos metabólicos son una de las partes más difíciles de manejar. Las concentraciones ideales de hemoglobina y de hematocrito oscilan entre 11-12 mg/dl y entre 33-36% respectivamente. Se debe mantener un control de la misma manera de calcio, fosforo y potasio.
Hematoma renal en paciente monorreno
Authors: Basco Prado Luis , Fariñas Rodríguez Silvia
Published: May 2012

Descrito en 1856 por Wunderlich, el hematoma perirrenal espontáneo es una patología infrecuente, en la que a pesar de llegar al diagnóstico de una manera relativamente sencilla con estudios imagen, el poder determinar la etiología representa un reto y es motivo de múltiples estudios y procedimientos invasivos, algunas veces sin poder llegar a esclarecer la causa1. Los hematomas renales y esplénicos están asociados con frecuencia a traumatismos abdominales y más raramente se deben a alteraciones de la coagulación e infecciones. Otras causas menos frecuentes son procesos inflamatorios, diátesis sanguínea, enfermedad poliquística, aneurismas, malformaciones arteriovenosas, infarto e idiopáticos2. El área subcapsular del riñón es un espacio potencial donde se pueden acumular los fluidos causando compresión al parénquima renal. Este tipo de fluidos puede consistir en colecciones de pus, sangre, linfa, exudado o trasudado3. Pacientes con traumatismos importantes, quemaduras extensas, operaciones quirúrgicas complicadas, procesos ginecoobstétricos graves, enfermedades infecciosas severas e intoxicaciones agudas, tienen alto riesgo para desarrollar Fracaso Renal Aguda4. Las técnicas continuas de reemplazo renal (TCRR) constituyen una de las principales técnicas y tratamientos de soporte de los pacientes con Fracaso renal Agudo (FRA). La incidencia de FRA en pacientes críticos ingresados en las unidades de cuidados intensivos (UCI) es claramente superior al resto de la población hospitalaria y puede llegar a afectar a más del 35% de estos pacientes5,6.
Localized Corrosion of Stainless Steel in a Nuclear Waste Cooling Water System— Part 1: Crevice Corrosion Studies
Authors: Whillock G.O.H. , Worthington S.E. , Donohoe C.J.
Published: May 2012

Parts of a nuclear waste cooling water system, constructed from an austenitic stainless steel, are known to be susceptible to localized corrosion. This is attributed to the presence of chloride ions in the water, albeit only at low concentrations (<10 mg/L), and oxidants produced by water radiolysis. Experiments were carried out using an engineered crevice connected to a large passive stainless steel surface to demonstrate the viability of crevice corrosion. Similar tests were undertaken to investigate the efficacy of nitrate as an inhibitor. In irradiated water containing up to 300 mg/L Cl− and at temperatures of up to 60°C, crevice corrosion of UNS 30403 and 18Cr-13Ni 1Nb was inhibited by nitrate added at molar ratios of approximately 2.9 to 5.7 with respect to chloride. Once corrosion is inhibited, the nitrate/chloride ratio can be reduced to maintain passivity, but a nitrate:chloride ratio of approximately 0.6 or lower is unlikely to be effective.
Microstructural Characterization and Corrosion Behavior of Activated Flux Gas Tungsten Arc-Welded and Multipass Gas Tungsten Arc-Welded Stainless Steel Weld Joints in Nitric Acid
Authors: Shankar A. Ravi , Niyanth S. , Vasudevan M. , Mudali U. Kamachi
Published: May 2012

AISI Type 304L (UNS S30403) austenitic stainless steels are widely used in spent nuclear fuel reprocessing plants, and welding is an indispensable tool used for joining these materials. In the present study, manual gas tungsten arc-welded (M-GTAW) and activated gas tungsten arc-welded (A-GTAW) weldments of Type 304L stainless steel were prepared to examine the microstructural and corrosion behavior of the weldments. A total of 6 passes were required to complete the 6 mm thick sample welding, and 16 passes were required for 12 mm thick sample welding using the M-GTAW process, compared to single-pass A-GTAW welding. Characterization of weld joints was done by radiography, optical microscopy, microhardness tester, a feritscope, and scanning electron microscopy (SEM). The optical microstructure of the fusion zone of weld joints showed delta ferrite in various morphologies. The presence of delta ferrite stringers were observed in the weld joints, extending from the weld metal to the base metal. The corrosion rate results showed that the M-GTAW sample showed only a marginal increase in the corrosion resistance when compared to those welded by the single-pass A-GTAW process. SEM examination revealed the morphology of attack in the base metal was predominantly intergranular while in the weld metal it was interdendritic. The SEM micrograph also showed preferential attack of the delta ferrite stringers.
Role of Sour Environments on the Corrosion Fatigue Growth Rate of X65 Pipe Steel
Authors: Gui F. , Ramgopal T. , Muller M.G.
Published: May 2012

Corrosion fatigue of C-Mn steels in sour environments is a concern in various offshore applications, particularly for flow-lines and risers. The commonly accepted mechanism of the enhanced fatigue crack growth rate (FCGR) behavior in these environments is hydrogen embrittlement. Hydrogen enters in the metal exposed to a sour environment through corrosion reactions occurring on the metal surface (referred to as bulk-charged hydrogen). During crack propagation, the fresh exposed metal at the crack tip under fatigue loading can also react with the corrosive environment and therefore generate hydrogen (referred to as crack tip hydrogen). Potentially, both of these two sources of hydrogen can impact the FCGR of the pipe steel. In this work, it was found that the bulk-charged hydrogen played a more dominant role in enhancing the FCGR of carbon steel in sour environments. The contribution to the FCGR from the crack tip hydrogen is not appreciable. The interaction of the freshly exposed metal with the corrosive environment could lead to the formation of iron(II) sulfide (FeS) film at the crack tip. This could lead to crack closure and decrease the effective ΔK and thus decrease the FCGR at low frequency, particularly at high H2S concentration and low pH environments, which is likely the cause for the observation of a plateau in FCGR in the low-frequency regime for carbon steel in the sour environment. Additionally, the experimental results suggest that although diffusible hydrogen was primarily responsible for the enhanced FCGR in the sour environment, the trapped hydrogen also played some role.
The isotopic record of Northern Hemisphere atmospheric carbon monoxide since 1950: implications for the CO budget
Authors: Wang Z. , Chappellaz J. , Martinerie P. , Park K. , Petrenko V. , Witrant E. , Emmons L. K. , Blunier T. , Brenninkmeijer C. A. M. , Mak J. E.
Published: May 2012

Abstract. We present a 60-year record of the stable isotopes of atmospheric carbon monoxide (CO) from firn air samples collected under the framework of the North Greenland Eemian Ice Drilling (NEEM) project. CO concentration, δ13C, and δ18O of CO were measured by gas chromatography/isotope ratio mass spectrometry (gc-IRMS) from trapped gases in the firn. We applied LGGE-GIPSA firn air models (Witrant et al., 2011) to correlate gas age with firn air depth and then reconstructed the trend of atmospheric CO and its stable isotopic composition at high northern latitudes since 1950. The most probable firn air model scenarios show that δ13C decreased slightly from −25.8‰ in 1950 to −26.4‰ in 2000, then decreased more significantly to −27.2‰ in 2008. δ18O decreased more regularly from 9.8‰ in 1950 to 7.1‰ in 2008. Those same scenarios show CO concentration increased gradually from 1950 and peaked in the late 1970s, followed by a gradual decrease to present day values (Petrenko et al., 2012). Results from an isotope mass balance model indicate that a slight increase, followed by a large reduction, in CO derived from fossil fuel combustion has occurred since 1950. The reduction of CO emission from fossil fuel combustion after the mid-1970s is the most plausible mechanism for the drop of CO concentration during this time. Fossil fuel CO emissions decreased as a result of the implementation of catalytic converters and the relative growth of diesel engines, in spite of the global vehicle fleet size having grown several fold over the same time period.
Stable carbon isotope fractionation in the UV photolysis of CFC-11 and CFC-12
Authors: Zuiderweg A. , Kaiser J. , Laube J. C. , Röckmann T. , Holzinger R.
Published: May 2012

Abstract. The chlorofluorocarbons CFC-11 (CFCl3) and CFC-12 (CF2Cl2) are stable atmospheric compounds that are produced at the earth's surface, but removed only at high altitudes in the stratosphere by photolytic reactions. Their removal liberates atomic chlorine that then catalytically destroys stratospheric ozone. For such long-lived compounds, isotope effects in the stratospheric removal reactions have a large effect on their global isotope budgets. We have demonstrated a photolytic isotope fractionation for stable carbon isotopes of CFC-11 and CFC-12 in laboratory experiments using broadband UV-C (190–230 nm) light. 13C/12C isotope fractionations (ε) range from (−23.8±0.9) to (−17.7±0.4) ‰ for CFC-11 and (−66.2±3.1) to (−51.0±2.9) ‰ for CFC-12 between 203 and 288 K, a temperature range relevant to conditions in the troposphere and stratosphere. These results suggest that CFCs should become strongly enriched in 13C with decreasing mixing ratio in the stratosphere, similar to what has been recently observed for CFC chlorine isotopes. In conjunction with the strong variations in CFC emissions before and after the Montréal Protocol, the stratospheric enrichments should also lead to a significant temporal increase in the 13C content of the CFCs at the surface over the past decades, which should be recorded in atmospheric air archives such as firn air.
Sulfuric acid nucleation: power dependencies, variation with relative humidity, and effect of bases
Authors: Zollner J. H. , Glasoe W. A. , Panta B. , Carlson K. K. , McMurry P. H. , Hanson D. R.
Published: May 2012

Abstract. Nucleation of particles composed of sulfuric acid, water, and nitrogen base molecules was studied using a continuous flow reactor. The particles formed from these vapors were detected with an ultrafine condensation particle counter, while vapors of sulfuric acid and nitrogen bases were detected by chemical ionization mass spectrometry. Variation of particle numbers with sulfuric acid concentration yielded a power dependency on sulfuric acid of 5 ± 1 for relative humidities of 14–68% at 296 K; similar experiments with varying water content yielded power dependencies on H2O of ~7. The critical cluster contains about 5 H2SO4 molecules and a new treatment of the power dependency for H2O suggests about 12 H2O molecules for these conditions. Addition of 2-to-45 pptv of ammonia or methyl amine resulted in up to millions of times more particles than in the absence of these compounds. Particle detection capabilities, sulfuric acid and nitrogen base detection, wall losses, and the extent of particle growth are discussed. Results are compared to previous laboratory nucleation studies and they are also discussed in terms of atmospheric nucleation scenarios.
The initiation of modern soft and hard Snowball Earth climates in CCSM4
Authors: Yang J. , Peltier W. R. , Hu Y.
Published: May 2012

Abstract. Geochemical and geological evidence has suggested that several global-scale glaciation events occurred during the Neoproterozoic Era in the interval from 750–580 million years ago. The initiation of these glaciations is thought to have been a consequence of the combined influence of a low level of atmospheric carbon dioxide concentration and an approximately 6% weakening of solar luminosity. The latest version of the Community Climate System Model (CCSM4) is employed herein to explore the detailed combination of forcings required to trigger such extreme glaciation conditions under present-day circumstances of geography and topography. It is found that runaway glaciation occurs in the model under the following conditions: (1) an 8–9% reduction in solar radiation with 286 ppmv CO2 or (2) a 6% reduction in solar radiation with 70–100 ppmv CO2. These thresholds are moderately different from those found to be characteristic of the previously employd CCSM3 model reported recently in Yang et al. (2012a,b), for which the respective critical points corresponded to a 10–10.5% reduction in solar radiation with 286 ppmv CO2 or a 6% reduction in solar radiation with 17.5–20 ppmv CO2. The most important reason for these differences is that the sea ice/snow albedo parameterization employed in CCSM4 is believed to be more realistic than that in CCSM3. Differences in cloud radiative forcings and ocean and atmosphere heat transports also influence the bifurcation points. These results are potentially very important, as they are to serve as control on further calculations which will be devoted to an investigation of the impact of continental configuration. We demonstrate that there exist ''soft Snowball'' Earth states, in which the fractional sea ice coverage reaches approximately 60–65%, land masses in low latitudes are covered by perennial snow, and runaway glaciation does not develop. This is consistent with our previous results based upon CCSM3. Although our results cannot exclude the possibility of a ''hard Snowball'' solution, it is suggested that a ''soft Snowball'' solution for the Neoproterozoic remains entirely plausible.
Development of a parameterization of black carbon aging for use in general circulation models
Authors: Oshima N. , Koike M.
Published: May 2012

Abstract. A parameterization of black carbon (BC) aging in the atmosphere is developed for use in general circulation models (GCMs) that separately treats size distributions of hydrophobic BC and hydrophilic BC using lognormal modes. The rate of BC aging is expressed as the conversion rate from hydrophobic BC to hydrophilic BC modes (i.e., inverse of the e-folding time of the conversion, 1/τBC). In this study, the conversion rates are estimated using results of detailed calculations by a size and mixing state resolved aerosol box model with numerous initial conditions. We introduce a new concept, the hydrophobic-BC-mass-normalized coating rate (VBC), defined as the rate of increase of the mass concentration of condensed materials on hydrophobic BC normalized by the hydrophobic BC mass concentration. Although the conversion rate largely varies depending on the atmospheric conditions and the concentrations of chemical species, we find that the variations of the conversion rate are generally expressed well by a unique function of VBC for given lognormal size distributions of hydrophobic BC. The parameterized conversion rate is expressed as a function of VBC, which enables the representation of diurnal and seasonal variations of the BC aging rate and its spatial differences in polluted and clean air, while other widely used constant conversion rates cannot. Application of our newly developed parameterization to GCMs will provide more reliable estimates of the spatial distribution of BC and its radiative effects at regional and global scales.
In search of robust flood risk management alternatives for the Netherlands
Authors: Klijn F. , Knoop J. M. , Ligtvoet W. , Mens M. J. P.
Published: May 2012

Abstract. The Netherlands' policy for flood risk management is being revised in view of a sustainable development against a background of climate change, sea level rise and increasing socio-economic vulnerability to floods. This calls for a thorough policy analysis, which can only be adequate when there is agreement about the "framing" of the problem and about the strategic alternatives that should be taken into account. In support of this framing, we performed an exploratory policy analysis, applying future climate and socio-economic scenarios to account for the autonomous development of flood risks, and defined a number of different strategic alternatives for flood risk management at the national level. These alternatives, ranging from flood protection by brute force to reduction of the vulnerability by spatial planning only, were compared with continuation of the current policy on a number of criteria, comprising costs, the reduction of fatality risk and economic risk, and their robustness in relation to uncertainties. We found that a change of policy away from conventional embankments towards gaining control over the flooding process by making the embankments unbreachable is attractive. By thus influencing exposure to flooding, the fatality risk can be effectively reduced at even lower net societal costs than by continuation of the present policy or by raising the protection standards where cost-effective.
Modeling long-term changes of the Black Sea ecosystem characteristics
Authors: Dorofeyev V. L. , Oguz T. , Sukhikh L. I. , Knysh V. V. , Kubryakov A. I. , Korotaev G. K.
Published: May 2012

Abstract. A three dimensional coupled physical-biological model is provided for the Black Sea to investigate its long-term changes under the synergistic impacts of eutrophication, climatic changes and population outbreak of the gelatinous invader Mnemiopsis leidyi. The model circulation field is simulated using the high frequency ERA40 atmospheric forcing as well as assimilation of the available hydrographic and altimeter sea level anomaly data for the 30 yr period of 1971–2001. The circulation dynamics are shown to resolve well the different temporal and spatial scales from mesoscale to sub-basin scale and from seasonal peaks to decadal scale trend-like changes. The biogeochemical model includes the main vertical biological and chemical interactions and processes up to the anoxic interface zone. Its food web structure is represented by two phytoplankton and zooplankton size groups, bacterioplankton, gelatinous carnivores Mnemiopsis and Aurelia, opportunistic species Noctiluca scientillans. The nitrogen cycling is accommodated by the particulate and dissolved organic nitrogen compartments and the dissolved inorganic nitrogen in the forms of ammonium, nitrite and nitrate. The ecosystem model is able to simulate successfully main observed features and trends of the intense eutrophication phase (from the early 1970s to the early 1990s), but points to its modification to simulate better the ecosystem conditions of the post-eutrophication phase.
Causes of IOL explantation in Spain
Authors: Fernández-Buenaga Roberto , Alio Jorge L. , Muñoz-Negrete Francisco J. , Barraquer Compte Rafael I. , Alio-Del Barrio Jorge L.
Published: May 2012

Purpose

To study the reasons and the demography of pseudophakic intraocular lens (IOL) explantation in Spain.

Methods

In this observational multicenter retrospective study, the cases studied correspond to the 15 centers that constitute the Nodo Calidad Visual y Cirugia Refractiva of the Red Tematica de Investigacion Cooperativa (RETICS) sponsored by the Spanish Ministry of Health. Clinical data from all the patients who underwent explantation were assessed. The different reasons that caused the decision of explantation were analyzed.

Results

A total of 257 explanted pseudophakic IOLs have been studied. Patients’ mean age when explantation occurred was 67.5 years (SD 13.5 [22-99]) and 135 were female (52.5%). The main causes for explantation were dislocation/decentration in 145 cases (56.3%), incorrect lens power in 33 cases (12.8%), IOL opacification in 29 eyes (11.3%), neuroadaptation failure in 16 cases (6.2%), pseudophakic bullous keratopathy in 6 eyes (2.3%), endophthalmitis in 5 cases (1.9%), and “other causes” in 23 eyes (8.9%). Treatment after explantation was posterior chamber IOL implantation in 149 eyes (58%), anterior chamber IOL implantation in 49 eyes (19.1%), aphakia in 39 eyes (15.2%), and missing information in 20 cases (7.8%). Mean time from implantation to explantation was 3.97 (SD 4.68 [0.005-21.1]) years.

Conclusions

Dislocation/decentration (most of the time with lens in the bag) is the main cause for explantation in Spain, followed by incorrect lens power (which decreased greatly over past years) and IOL opacification. Posterior chamber IOL implantation is the most elected treatment after explantation.
Do Centrally Committed Electricity Markets Provide Useful Price Signals?
Authors: Sioshansif Ramteen , Tignor Ashlin
Published: May 2012

Centrally committed markets rely on an independent system operator to determine the commitment and dispatch of generators. This is done by solving a unit commitment model, which is an NP-hard mixed integer program that is rarely (if ever) solved to complete optimality. We demonstrate, using a case study based on the ISO New England system, that near-optimal solutions that are very close to one another in terms of overall system cost can yield very different generator surpluses and prices. We further demonstrate that peaking generators are more prone to surplus differences between near-optimal solutions and that transmission buses that are most prone to binding transmission constraints experience the greatest price fluctuations. Based on these findings, we discuss the potential benefits of a decentralized market design in providing more robust price signals.
A Rough Analysis: Valuing Gas Storage
Authors: Giulietti Monica , Grossi Luigi , Waterson Michael
Published: May 2012

This paper studies the impact of a fire in 2006 which removed the possibility of access to the Rough gas storage facilities covering over 80% of total UK storage, at a time when major withdrawals from storage would have likely taken place. Implicitly, it shows the value of such gas storage facilities, in a country with relatively little storage, where we might therefore see a considerable impact. We find that the major effect on activity was through an increased sensitivity of supply to prices and an increased variance in this sensitivity, not through non-price rationing.
Controlled Release of Antiproliferative Drugs From Polymeric Systems for Stent Applications and Local Cancer Treatment
Authors: Kraitzer Amir , Zilberman Meital
Published: May 2012

Restenosis (re‐narrowing of the blood vessel wall) and cancer are two different pathologies that have drawn extensive research attention over the years. Antiproliferative drugs such as paclitaxel inhibit cell proliferation and are therefore effective in the treatment of cancer as well as neointimal hyperplasia, which is known to be the main cause of restenosis. Drug‐eluting stents (DES) significantly reduce the incidence of in‐stent restenosis (ISR), which was once considered a major adverse outcome of percutaneous coronary stent implantations. Localized release of antiproliferative drugs interferes with the pathological proliferation of vascular smooth muscle cells (VSMC), which is the main cause of ISR. Conventional approaches to treating cancer are mainly surgical excision, irradiation, and chemotherapy. In cancer therapy, surgical treatment is usually performed on patients with a resectable carcinoma. An integrated therapeutic approach, such as the addition of a delivery system loaded with an antiproliferative drug at the tumor resection site, is desirable. This will provide a high local concentration of a drug, that is, detrimental to malignant cells which may have survived surgery, thus preventing re‐growth and metastasis of the tumor. The present review describes recent advances in systems for controlled release of antiproliferative agents. It describes basic concepts in drug delivery systems and antiproliferative drugs and then focuses on both types of systems: stents with controlled release of antiproliferative agents, and drug‐eluting particles and implants for local cancer treatment. The last part of this article is dedicated to our novel drug‐eluting composite fiber structures, which can be used as basic stent elements as well as for local cancer treatment.
A Universal Scaling Law to Predict the Efficiency of Magnetic Nanoparticles as MRI T2‐Contrast Agents
Authors: Vuong Quoc L. , Berret Jean‐François , Fresnais Jérôme , Gossuin Yves , Sandre Olivier
Published: May 2012

Magnetic particles are very efficient magnetic resonance imaging (MRI) contrast agents. In recent years, chemists have unleashed their imagination to design multi‐functional nanoprobes for biomedical applications including MRI contrast enhancement. This study is focused on the direct relationship between the size and magnetization of the particles and their nuclear magnetic resonance relaxation properties, which condition their efficiency. Experimental relaxation results with maghemite particles exhibiting a wide range of sizes and magnetizations are compared to previously published data and to well‐established relaxation theories with a good agreement. This allows deriving the experimental master curve of the transverse relaxivity versus particle size and to predict the MRI contrast efficiency of any type of magnetic nanoparticles. This prediction only requires the knowledge of the size of the particles impermeable to water protons and the saturation magnetization of the corresponding volume. To predict the T2 relaxation efficiency of magnetic single crystals, the crystal size and magnetization – obtained through a single Langevin fit of a magnetization curve – is the only information needed. For contrast agents made of several magnetic cores assembled into various geometries (dilute fractal aggregates, dense spherical clusters, core–shell micelles, hollow vesicles…︁), one needs to know a third parameter, namely the intra‐aggregate volume fraction occupied by the magnetic materials relatively to the whole (hydrodynamic) sphere. Finally a calculation of the maximum achievable relaxation effect – and the size needed to reach this maximum – is performed for different cases: maghemite single crystals and dense clusters, core‐shell particles (oxide layer around a metallic core) and zinc‐manganese ferrite crystals.
A complex chromosomal rearrangement involving chromosomes 2, 5, and X in autism spectrum disorder
Authors: Griesi‐Oliveira Karina , Moreira Danielle de Paula , Davis‐Wright Nicole , Sanders Stephan , Mason Christopher , Orabona Guilherme Müller , Vadasz Estevão , Bertola Débora Romeo , State Matthew W. , Passos‐Bueno Maria Rita
Published: May 2012

Here, we describe a female patient with autism spectrum disorder and dysmorphic features that harbors a complex genetic alteration, involving a de novo balanced translocation t(2;X)(q11;q24), a 5q11 segmental trisomy and a maternally inherited isodisomy on chromosome 5. All the possibly damaging genetic effects of such alterations are discussed. In light of recent findings on ASD genetic causes, the hypothesis that all these alterations might be acting in orchestration and contributing to the phenotype is also considered. © 2012 Wiley Periodicals, Inc.
Genetic and environmental causes of variation in perceived loneliness in young people
Authors: Waaktaar Trine , Torgersen Svenn
Published: May 2012

Loneliness is prevalent in adolescence, despite the widespread expectation directed to young people to start building close relationships beyond the nuclear family. The aim of the present study was to explore the causal genetic and environmental structure behind variability in adolescents' perceived loneliness. Seven national cohorts (ages 12–18 years) of Norwegian twins reared together (1,394 twin pairs) participated. Perceived loneliness was measured with five items from the UCLA Loneliness Scale. Data were collected from mothers, fathers, and twins' self ratings by means of a posted questionnaire. Biometric analyses were applied, testing the causal architecture of loneliness within a psychometric model with one common latent factor in addition to specific genetic and environmental sources influencing the scores of each informant. The results showed a heritability (h2) of 75% on the latent perceived loneliness factor, and nonshared environmental effects (e2) explaining the remaining 25% of the latent factor variance. There were also significant rater‐specific genetic and nonshared environmental effects. No shared environmental effects were found in the model, and there were no sex differences in the estimates. This study showed that variation in perceived loneliness in adolescents is highly genetic. Additional genetic and nonshared environmental etiological sources are to some extent represented in the scores of the specific rater. © 2012 Wiley Periodicals, Inc.
Effect of porogenic solvent on the porous properties of polymer monoliths
Authors: Yu Suzhu , Ng Fern Lan , Ma Khin Cho Cho , Mon Aye Aye , Ng Feng Lin , Ng Yen Yong
Published: May 2012

Polymer monoliths with open pores and median pore size of about 15 nm–3 μm have been successfully synthesized by photoinitiated polymerization of butyl methacrylate and ethylene glycol dimethacrylate monomers. The solubility of the monomers in a porogenic solvent is determined by Hildebrand solubility parameter, and it is found that it has great effect on the pore size of the polymers synthesized. Polymers with larger pores are usually generated with poorer solvents for the monomers. However, polymers with different pore sizes and porosities have been obtained using porogenic solvents with similar Hildebrand solubility parameters. The evaporation rate of the porogenic solvents might be another critical factor affecting the properties of the polymer monoliths. Moreover, the effect of water as a cosolvent on the pore size and porosity of the polymers have also been investigated. Polymers with larger pore size have been prepared with the presence of water due to the occurrence of earlier phase separation in the polymerization. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Formation of an interconnected lamellar structure in PVDF membranes with nanoparticles addition via solid‐liquid thermally induced phase separation
Authors: Ma Wenzhong , Zhang Jun , Bruggen Bart Van der , Wang Xiaolin
Published: May 2012

Novel microporous membranes were prepared via thermally induced solid‐liquid (S‐L) phase separation of mixtures containing poly(vinylidene fluoride) (PVDF)/diphenyl ketone (DPK)/nanoparticles [such as montmorillonite (MMT) and polytetrafluoroethylene (PTFE)] in diluted systems with a mass ratio of 29.7/70/0.3 wt %. The crystallization and melting characteristics of these diluted systems were investigated by polarizing optical microscopy (POM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and wide angle X‐ray diffraction (WAXD). The nanoparticle structure and the interaction between PVDF chains and nanoparticle surfaces determined the crystallization behavior and morphology of the PVDF membrane. The addition of MMT and PTFE had a significant nucleation enhancement on the crystallization of PVDF accompanied by S‐L phase separation during the thermally induced phase separation (TIPS) process. It was observed that an interconnected lamellar structure was formed in these two membranes, leading to a higher tensile strength compared with that of the reference membrane without nanoparticles addition. Additionally, addition of MMT facilitates the fiber‐like β phase crystal formation, resulting in the highest elongation at break. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
High temperature ablation of highly filled polymer‐layered silicate nanocomposites
Authors: Paydayesh Azin , Kokabi Mehrdad , Reza Bahramian Ahmad
Published: May 2012

At instantaneous thermal shocks and high temperature conditions, using the charring ablative heat shields is more effective than the other heat protection methods. In recent years, low‐filled layered silicate polymeric nanocomposites were introduced as new class of ablative materials. In this work, highly filled ablative polymeric nanocomposite is prepared and its thermal stability and ablation mechanism is studied under high external heat flux. The thermal degradation kinetics during pyrolysis, the variation of thermophysical properties as a result of ablation process and mathematical modeling of ablation process are performed for highly filled ablative polymeric nanocomposite samples compared with those of their composite counterparts under oxyacetylene flame test. The results show that the ablation performance of highly filled polymeric nanocomposite is higher than that of the composite, and the mathematical model is adequately confirmed by the experimental data of the thermophysical and ablation properties of highly filled nanocomposites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Grafted polysaccharides based on acrylamide and N,N‐dimethylacrylamide: Preparation and investigation of their flocculation performances
Authors: Kolya Haradhan , Tripathy Tridib
Published: May 2012

The graft copolymerization of N,N‐dimethylacrylamide (DMA) and acrylamide (AM) were carried out onto different polysaccharide backbones separately. The graft copolymers were synthesized by ceric ion induced redox polymerization technique. Three polysaccharides were used, namely hydroxyethyl starch (HES), hydroxyethyl cellulose (HEC) and Amylopectin (AP), for the grafting reactions. Among the three polysaccharides, HEC has linear structure, while HES and AP have a branch one. The graft copolymers were characterized by intrinsic viscosity measurements, FTIR spectroscopy, NMR (both 1H and 13C) spectroscopy, and thermal analysis. Flocculation performances of the graft copolymers were evaluated in 1 wt % kaolin and in 0.25 wt % iron ore suspensions. A detailed comparative study of the flocculation properties of the synthetic graft copolymers was also made. It showed that graft copolymers based on DMA were better flocculants than those based on AM. Among the synthetic graft copolymers, HES‐g‐Poly (DMA) performed best when compared with the other synthetic graft copolymers as well as to the commercial flocculants in the same suspensions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Compatibilization of bentonite filled ethylene‐propylene‐diene monomer composites: Effect of maleic anhydride grafted EPDM
Authors: Ismail H. , Mathialagan M.
Published: May 2012

Maleic anhydride grafted ethylene‐propylene‐diene monomer (MAH‐g‐EPDM) was prepared by peroxide‐initiated melt grafting of MAH onto EPDM using a HAAKE internal mixer at 180°C and 60 rpm for 5 min and it was used as compatibilizer to enhance the compatibility of EPDM/Bt composites. The composites were prepared using a laboratory scale two roll mill, model XK‐160 at room temperature. The addition of 10 parts per hundred rubber (phr) of MAH‐g‐EPDM into EPDM/Bt composite results in significantly improved tensile properties compared with the uncompatibilized EPDM/Bt composites. Curing behavior, tensile properties, solvent resistance, and the rubber‐filler interaction of compatibilized and uncompatibilized EPDM/Bt composites were investigated. The cure time (t90), scorch time (tS2), maximum torque (MH), and minimum torque (ML) of compatibilized composites were increased upon addition of MAH‐g‐EPDM. Compared with uncompatibilized EPDM/Bt composites, the tensile properties, solvent resistance, and rubber‐filler interaction of compatibilized EPDM/Bt composites were all improved. SEM micrographs of tensile fractured surfaces of compatibilized EPDM/Bt composites showed a better dispersion of Bt and interfacial adhesion between EPDM and Bt compared with uncompatibilized EPDM/Bt composites. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of a phenylene phenyl phosphine oligomer and its flame retardancy for polycarbonate
Authors: Zhao Wei , Li Bin , Xu Miaojun , Liu Fangmeng , Guan Limin
Published: May 2012

A novel flame retardant, phenylene phenyl phosphine oligomer (PPPO) was synthesized and its chemical structure was characterized using Fourier transform infrared spectroscopy, 1H, 13C, 31P nuclear magnetic resonance spectroscopy and mass spectrometer. PPPO was used to impart flame retardancy to polycarbonate (PC). Combustion behaviors and thermal degradation properties of PC/PPPO system were assayed by limiting oxygen index (LOI), vertical burning test (UL‐94), cone calorimeter test, and thermogravimetric analysis. PC/6 wt % PPPO passed UL‐94 V‐0 rating with 3.0 mm samples and the LOI value was 34.1%, and PC/8 wt % PPPO also passed UL‐94 V‐0 rating with 1.6 mm samples and the LOI value was 36.3%. Scanning electron microscopy reveals that the char properties had crucial effects on the flame retardancy of PC. Mechanical properties and water resistance of PC/PPPO system were also measured. After water resistance test, PC/6 wt % PPPO with 3.0 mm samples and PC/8 wt % PPPO with 1.6 mm samples kept V‐0 rating and mass loss was only 0.2%. The results revealed that PPPO was an efficient flame retardant for PC. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Antimicrobial activity of cotton fabrics treated with curcumin
Authors: Reddy Narendra , Han Shinyoung , Zhao Yi , Yang Yiqi
Published: May 2012

Curcumin, a yellow pigment known to have various biological activities, was applied onto cotton as an antimicrobial agent. Curcumin could provide both color and antimicrobial activity to cotton and can be dyed using a batch or continuous process. However, curcumin and cotton have low affinity and therefore the ability of curcumin to impart durable antimicrobial activity on cotton needs to be studied. In this research, the ability of curcumin dyed onto cotton fabrics to inhibit the growth of Escherichia coli and Staphylococcus aureus was studied. Relationships that can predict the rate of inhibition based on the curcumin concentration or shade depth (K/S values) were developed without the need for an antimicrobial test. Durability of antimicrobial activity to laundering and to light was also studied. Curcumin was more effective in inhibiting S. aureus than E. coli. The reduction of bacteria and durability of antimicrobial activity of curcumin to laundering was inferior on cotton fabrics compared with wool. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Structure property relations in polyethylene oxide/starch blended films using WAXS techniques
Authors: Jagadish Rampura. S. , Raj Baldev , Parameswara Puttanna , Somashekar Rudrappa
Published: May 2012

A series of polyethylene oxide (PEO)/starch blends were prepared by extrusion and their films were prepared by compression molding. It was observed that the presence of characteristic peaks of PEO and starch at 845 and 1643.7 cm−1, respectively, in FTIR spectra of PEO/starch blends favors the blending of PEO/starch. The physicomechanical and optical properties of PEO/starch‐blended films were measured. The tensile strength of the blended films decreased, whereas the haze values increased with an enhanced starch concentration in PEO/starch blends. The results obtained were correlated with microstructural parameters such as, crystallite size and lattice strain determined using wide angle X‐ray scattering (WAXS) data. The X‐ray line profile analysis shows that the crystallite shape area is maximum in PEO and decreases with the addition of starch. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of stabilization temperature on gas permeation properties of carbon hollow fiber membrane
Authors: Wan Salleh Wan Norharyati , Ismail Ahmad Fauzi
Published: May 2012

Carbon hollow fiber membranes (CHFMs) derived from polymer blend of polyetherimide (PEI) and polyvinylpyrrolidone (PVP) were extensively prepared through stabilization under air atmosphere followed by carbonization under N2 atmosphere. The effects of the stabilization temperature on the morphological structure, chemical structure, and gas permeation properties were investigated thoroughly by means of scanning electron microscopy, Fourier transform infrared spectroscopy, and single gas permeation system. The experiment results indicate that the transport mechanism of small gas molecules of N2, CO2, and CH4 is dominated by the molecular sieving effect. Based on morphological structure and gas permeation properties, an optimum stabilization condition for the preparation of CHFM derived from PEI/PVP was found at 300°C under air atmosphere. The selectivity of ˜55 and 41 for CO2/CH4 and CO2/N2, respectively, were obtained for CHFMs prepared at stabilization temperature of 300°C. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013