bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiological and clinical examination in the diagnosis of Spigelian hernias
Authors: Light D , Chattopadhyay D , Bawa S
Published: March 2013

Introduction

Spigelian hernia are rarely reported lateral abdominal wall hernias. Clinical diagnosis of a suspected hernia can be challenging owing to vague presenting symptoms and signs. This study aimed to investigate the accuracy of preoperative imaging and clinical examination in the diagnosis of Spigelian hernias.

Methods

A retrospective analysis was performed of patients who presented to North Tyneside and Wansbeck General Hospitals between 1998 and 2010. All patients were assessed by a consultant general surgeon in the outpatient clinic or on the surgical admissions ward. Patients were included who presented with a history suggestive of a Spigelian hernia and a palpable lump or equivocal clinical examination. All patients proceeded to surgery, which was used as the reference standard.

Results

Overall, correlation with operative findings showed computed tomography (CT) to have a sensitivity of 100% and a positive predictive value (PPV) of 100%. Ultrasonography had a sensitivity of 90% and a PPV of 100%. Clinical assessment alone had a sensitivity of 100% and a PPV of 36%.

Conclusions

This study shows that ultrasonography and CT have a high sensitivity and PPV in relation to occult Spigelian hernias. When no obvious Spigelian hernia is present, patients should be evaluated with radiological investigation to establish a diagnosis. Owing to diagnostic uncertainty, a laparoscopic approach should be favoured.
Management of colorectal cancer liver metastasis in a patient with immune thrombocytopaenia
Authors: Yacob M , Raju RS , Vyas FL , Joseph P , Sitaram V
Published: March 2013

Immune thrombocytopaenia (ITP) was referred to previously as idiopathic thrombocytopaenic purpura and is usually of autoimmune or viral aetiology. Colorectal cancer liver metastasis with concomitant ITP is rare and only three cases have been reported in the English literature. Adverse effects of adjuvant chemotherapy may aggravate ITP. The sequencing of chemotherapy, operation for the primary and liver metastasis, and a decision on splenectomy is important. We present our experience in the management of a 52-year-old man who, having undergone anterior resection one year earlier for carcinoma of the rectum, presented with liver metastasis and ITP. He underwent splenectomy with hepatectomy prior to chemotherapy.
Subjective wellbeing: a primer for poverty analysts
Authors: Venkatapuram Sridhar
Published: March 2013

The article reviews the current theory and measurement of subjective wellbeing (SWB). The first two sections discuss growing efforts in many countries to measure and monitor national wellbeing, particularly in the United Kingdom. The third and fourth sections discuss the novelty and controversies about SWB research. It concludes that a critical approach is essential in evaluating SWB research but dismissing it offhand or framing it as antithetical to objective wellbeing is misconceived. The pressing issue for poverty research and public policy is to determine which insights about SWB are worth using, and how much space within conceptions of wellbeing used in public policy should be given to SWB.
Poor and dissatisfied? Income poverty, poverty transitions and life satisfaction in Chile
Authors: Samman Emma , Santos María Emma
Published: March 2013

Chile is an interesting country in which to study the relationship between poverty and subjective wellbeing, having experienced a remarkable fall in poverty over the past two decades. This paper explores how poverty status and transitions in and out of poverty contributed to life satisfaction in the late 2000s. Using new data for 2006 and 2009, we find that poor people were more dissatisfied with life than the non-poor and that income gains did not appreciably affect the satisfaction of the poor while they remained below the poverty line. People who were not poor in either period exhibited higher satisfaction than those who were poor in both periods, while those who escaped poverty between 2006 and 2009 exhibited higher satisfaction than those who remained poor. In addition, people who fell into poverty in 2009 were no more or no less satisfied with their lives than those who were poor in both periods. The evidence suggests poor people may not have adapted to their circumstances, in contrast to much literature exploring income dynamics and life satisfaction, and also that people–s recent experiences appear to affect their perceptions more than more distant ones.
Determination of the diffusion of monovalent cations into wood under isothermal conditions based on LiCl impregnation of Norway spruce
Authors: Kolavali Reddysuresh , Theliander Hans
Published: March 2013

The impregnation of wood pieces in the course of pulping can be divided into primary (advective mass transport) and secondary (diffusive mass transport) penetration. Little is known about the latter partly because of the difficulties in the determination of the relevant diffusivities for this system. In the present article, a precise experimental methodology has been developed to measure the concentration profiles of cations as a function of wood piece dimensions, impregnation time, temperature, and wood structure. The cation concentration can be measured at any position in the impregnated wood piece. The impregnation of Norway spruce wood samples with LiCl was investigated. The impregnated wood pieces were cut mechanically into cubes, which were cut in slices by means of a microtome, and the eluate of the 0.4-mm-thick slices in HNO3 was analyzed by flame atomic emission spectroscopy. The method gave reasonable results, and defects in the wood piece (microcracks) were detectable. The preliminary results presented here have to be verified with more replicates due to the heterogeneity of wood.
Taxonomic status of Mus talpinus Lund (Rodentia: Sigmodontinae) from the Quaternary deposits of Lagoa Santa, Minas Gerais, Brazil and its paleoenvironmental meaning
Authors: Pardiñas Ulyses F. J. , Teta Pablo
Published: March 2013

Mus talpinus, a fossil sigmodontine rodent exhumated by P. W. Lund from Quaternary deposits in the Lagoa Santa area, Brazil, has been varyingly allocated to the genera Oxymycterus, Blarinomys or Juscelinomys. After our examination of the holotype, an anterior fragment of the skull from Lapa da Serra das Abelhas, Minas Gerais, Brazil, we refer the name talpinus to the genus Brucepattersonius. These mice are sylvan akodontines, widespread in the Atlantic Forest, with the nearest extant record approximately 250 km southeast of Lagoa Santa. The addition of Brucepattersonius to the fossil sigmodontine fauna of Lagoa Santa suggests a non-analogous assemblage of species in this area during the Late Pleistocene.
Mortality, ADHD, and Psychosocial Adversity in Adults With Childhood ADHD: A Prospective Study
Authors: Barbaresi William J. , Colligan Robert C. , Weaver Amy L. , Voigt Robert G. , Killian Jill M. , Katusic Slavica K.
Published: March 2013

OBJECTIVE:

We examined long-term outcomes of attention-deficit/hyperactivity disorder (ADHD) in a population-based sample of childhood ADHD cases and controls, prospectively assessed as adults.

METHODS:

Adults with childhood ADHD and non-ADHD controls from the same birth cohort (N = 5718) were invited to participate in a prospective outcome study. Vital status was determined for birth cohort members. Standardized mortality ratios (SMRs) were constructed to compare overall and cause-specific mortality between childhood ADHD cases and controls. Incarceration status was determined for childhood ADHD cases. A standardized neuropsychiatric interview was administered.

RESULTS:

Vital status for 367 childhood ADHD cases was determined: 7 (1.9%) were deceased, and 10 (2.7%) were currently incarcerated. The SMR for overall survival of childhood ADHD cases versus controls was 1.88 (95% confidence interval [CI], 0.83–4.26; P = .13) and for accidents only was 1.70 (95% CI, 0.49–5.97; P = .41). However, the cause-specific mortality for suicide only was significantly higher among ADHD cases (SMR, 4.83; 95% CI, 1.14–20.46; P = .032). Among the childhood ADHD cases participating in the prospective assessment (N = 232; mean age, 27.0 years), ADHD persisted into adulthood for 29.3% (95% CI, 23.5–35.2). Participating childhood ADHD cases were more likely than controls (N = 335; mean age, 28.6 years) to have ≥1 other psychiatric disorder (56.9% vs 34.9%; odds ratio, 2.6; 95% CI, 1.8–3.8; P < .01).

CONCLUSIONS:

Childhood ADHD is a chronic health problem, with significant risk for mortality, persistence of ADHD, and long-term morbidity in adulthood.
Thrombotic Storm in a Teenager With Previously Undiagnosed Ulcerative Colitis
Authors: Maggi Umberto , Rossi Giorgio , Avesani Ettore Contessini , Artoni Andrea , Caprioli Flavio , Napolitano Luisa , Martinelli Ida
Published: March 2013

Venous thrombosis can complicate inflammatory bowel diseases, both in adult and pediatric patients, and a few adult cases of thrombotic storm, ie, thrombosis at multiple sites occurring over a period of a few days to a few weeks, have been described. However, venous thrombosis as the first manifestation of an inflammatory bowel disease is extremely rare. We report the case of a 14-year-old girl presenting with ascites and marked hypertransaminasemia resulting from hepatic vein occlusion (Budd-Chiari syndrome). Despite anticoagulant therapy, in the following days she developed criteria suggestive of thrombotic storm to include cerebral vein, right atrial thrombosis, and bilateral pulmonary embolism. Thrombolytic treatment with recombinant-tissue plasminogen activator was started, with resolution of all venous thromboses and without bleeding complications. Additional examinations revealed a severely active ulcerative pancolitis, which did not respond to medical treatment and required surgery. No thrombophilia abnormality nor other risk factors for thrombosis were detected. We conclude that an underlying inflammatory state, such as ulcerative colitis, should be suspected in pediatric patients with venous thrombosis storm.
A Parent-Focused Intervention to Reduce Infant Obesity Risk Behaviors: A Randomized Trial
Authors: Campbell Karen J. , Lioret Sandrine , McNaughton Sarah A. , Crawford David A. , Salmon Jo , Ball Kylie , McCallum Zoe , Gerner Bibi E. , Spence Alison C. , Cameron Adrian J. , Hnatiuk Jill A. , Ukoumunne Obioha C. , Gold Lisa , Abbott Gavin , Hesketh Kylie D.
Published: March 2013

OBJECTIVE:

To assess the effectiveness of a parent-focused intervention on infants’ obesity-risk behaviors and BMI.

METHODS:

This cluster randomized controlled trial recruited 542 parents and their infants (mean age 3.8 months at baseline) from 62 first-time parent groups. Parents were offered six 2-hour dietitian-delivered sessions over 15 months focusing on parental knowledge, skills, and social support around infant feeding, diet, physical activity, and television viewing. Control group parents received 6 newsletters on nonobesity-focused themes; all parents received usual care from child health nurses. The primary outcomes of interest were child diet (3 × 24-hour diet recalls), child physical activity (accelerometry), and child TV viewing (parent report). Secondary outcomes included BMI z-scores (measured). Data were collected when children were 4, 9, and 20 months of age.

RESULTS:

Unadjusted analyses showed that, compared with controls, intervention group children consumed fewer grams of noncore drinks (mean difference = –4.45; 95% confidence interval [CI]: –7.92 to –0.99; P = .01) and were less likely to consume any noncore drinks (odds ratio = 0.48; 95% CI: 0.24 to 0.95; P = .034) midintervention (mean age 9 months). At intervention conclusion (mean age 19.8 months), intervention group children consumed fewer grams of sweet snacks (mean difference = –3.69; 95% CI: –6.41 to –0.96; P = .008) and viewed fewer daily minutes of television (mean difference = –15.97: 95% CI: –25.97 to –5.96; P = .002). There was little statistical evidence of differences in fruit, vegetable, savory snack, or water consumption or in BMI z-scores or physical activity.

CONCLUSIONS:

This intervention resulted in reductions in sweet snack consumption and television viewing in 20-month-old children.
Advanced β-Solidifying Titanium Aluminides – Development Status and Perspectives
Authors: Clemens Helmut , Schloffer Martin , Schwaighofer Emanuel , Werner Robert , Gaitzenauer Andrea , Rashkova Boryana , Schmoelzer Thomas , Pippan Reinhard , Mayer Svea
Published: March 2013

After almost three decades of intensive fundamental research and development activities intermetallic titanium aluminides based on the -TiAl phase have found applications in automotive and aircraft engine industries. The advantages of this class of innovative high-temperature materials are their low density as well as their good strength and creep properties up to 750°C. A drawback, however, is their limited ductility at room temperature, which is reflected by a low plastic strain at fracture. This behavior can be attributed to a limited dislocation movement along with microstructural inhomogeneity. Advanced TiAl alloys, such as β-solidifying TNM™ alloys, are complex multi-phase materials which can be processed by ingot or powder metallurgy as well as precision casting methods. Each production process leads to specific microstructures which can be altered and optimized by thermo-mechanical processing and/or subsequent heat-treatments. The background of these heat-treatments is at least twofold, i.e. concurrent increase of ductility at room temperature and creep strength at elevated temperature. In order to achieve this goal the knowledge of the occurring solidification processes and phase transformation sequences is essential. Therefore, thermodynamic calculations were conducted to predict phase fraction diagrams of engineering TiAl alloys. After experimental verification, these phase diagrams provided the base for the development of heat treatments to adjust balanced mechanical properties. To determine the influence of deformation and kinetic aspects, sophisticated ex- and in-situ methods have been employed to investigate the evolution of the microstructure during thermo-mechanical processing and subsequent multi-step heat-treatments. For example, in-situ high-energy X-ray diffraction was conducted to study dynamic recovery and recrystallization processes during hot-deformation tests. Summarizing all results a consistent picture regarding microstructure formation and its impact on mechanical properties in TNM alloys can be given.
Structures and Function of Remora Adhesion
Authors: Nadler Jason H. , Mercer Allison J. , Culler Michael , Ledford Keri A. , Bloomquist Ryan , Lin Angela
Published: March 2013

Remoras (echeneid fish) reversibly attach and detach to marine hosts, almost instantaneously, to “hitchhike” and feed. The adhesion mechanisms that they use are remarkably insensitive to substrate topology and quite different from the latching and suction cup-based systems associated with other species at similar length scales. Remora adhesion is also anisotropic; drag forces induced by the swimming host increase adhesive strength, while rapid detachment occurs when the remora reverses this shear load. In this work, an investigation of the adhesive system’s functional morphology and tissue properties was carried out initially through dissection and x-ray microtomographic analyses. Resulting finite element models of these components have provided new insights into the adaptive, hierarchical nature of the mechanisms and a path toward a wide range of engineering applications.
Characterization of Ni3(Si,Ti) intermetalic alloys synthesized by powder metallurgical method
Authors: Miura Yuki , Kaneno Yasuyuki , Takasugi Takayuki , Kakituji Atsushi
Published: March 2013

A Ni3(Si,Ti) intermetalic alloy was synthesized by the powder metallurgy method using elemental powders. The raw powder mixtures with various compositions were sintered by a spark plasma sintering apparatus and then homogenized at high temperatures. Microstructure, hardness, tensile properties and density of the sintered alloys were investigated as functions of the chemical composition and sintering temperature. It was found that a highly-densified Ni3(Si,Ti) sintered alloy was obtained by choosing proper chemical composition and sintering temperature. Also, the Ni3(Si,Ti) sintered alloy with an L12 single-phase microstructure exhibited high hardness and tensile strength.
Technetium-99m Transport and Immobilisation in Porous Media: Development of a Novel Nuclear Imaging Technique
Authors: Corkhill Claire L. , Bridge Jonathan W. , Hillel Philip , Gardner Laura J. , Banwart Steven A. , Hyatt Neil C.
Published: March 2013

Technetium-99, a β-emitting radioactive fission product of235U, formed in nuclear reactors, presents a major challenge to nuclear waste disposal strategies. Its long half-life (2.1 x 105years) and high solubility under oxic conditions as the pertechnetate anion [Tc(VII)O4] is particularly problematic for long-term disposal of radioactive waste in geological repositories. In this study, we demonstrate a novel technique for quantifying the transport and immobilisation of technetium-99m, a γ-emitting metastable isomer of technetium-99 commonly used in medical imaging. A standard medical gamma camera was used for non-invasive quantitative imaging of technetium-99m during co-advection through quartz sand and various cementitious materials commonly used in nuclear waste disposal strategies. Spatial moments analysis of the resulting99mTc plume provided information about the relative changes in mass distribution of the radionuclide in the various test materials.99mTc advected through quartz sand demonstrated typical conservative behaviour, while transport through the cementitious materials produced a significant reduction in radionuclide centre of mass transport velocity over time. Gamma camera imaging has proven an effective tool for helping to understand the factors which control the migration of radionuclides for surface, near-surface and deep geological disposal of nuclear waste.
Effects of a Polycaprolactone (PCL) Tissue Scaffold in Rattus norvegicus on Blood Flow
Authors: Bhat Satish , Chen Christopher , Day Deborah A.
Published: March 2013

Tissue engineering aims to save lives by producing synthetic organs and bone. This study is attempting to determine what effects a polycaprolactone (PCL) scaffold will have on the blood flow of Rattus norvegicus, as measured by the number of platelets. Prior to experimentation, it was hypothesized that the polycaprolactone scaffold would maintain and/or increase the number of platelets when compared to the control group. This was developed based on prior research that showed polylactic acid (PLA), a polymer being used currently, and polycaprolactone had similar characteristics like boiling point, melting point, and glass transition temperature. To test this hypothesis, the PCL, created from an existing protocol, was used to mold a scaffold in vitro. Three groups of rats were identified, then further split into an “A” and “B” subdivision with 5 members in each. All “A” subdivision members received the scaffold, while the "B" factions lacked it. Each rat underwent surgery to remove 1mm of the right ventricle, which was replaced by the PCL scaffold in the experimental group. The control group did not have the scaffold replacement. Without this piece of the right ventricle, prior research conducted at the University of Virginia in 2006 suggests that the rats would die within one week. However, in the experimental group of rats, the missing piece of the ventricle was replaced with the scaffold, so if it were accepted then the rats would survive beyond 1week. All rats in the experimental group died exactly 1 week after the control group as predicted before experimentation. After all of the rats had a 1-week acclimation period, a 1mm^2 slice of the heart was extracted and then the number of platelets was counted using a phase contrast microscope. The heart extraction was prepared in a petri dish and then placed into a hemocytometer, splitting the dish into smaller sections making it possible to count. The data supports the hypothesis whereby an average 12% increase in the number of platelets in the rats with the PCL scaffold versus the group without it was seen. This increase in platelet count reflects an increase in blood flow. A statistical t-test was conducted on each trial (n=5 per group, n=10 total per trial) comparing experimental versus control group to calculate a p-value. The p-values were 0.034, 0.045, and 0.022, respectively which indicates statistical significance since the value is less than 0.05. After all experimentation, the benefits of using PCL in tissue engineering were examined. For example, PCL costs $80 less to produce per kilogram than polylactic acid. This study suggests that PCL would be a viable candidate for tissue engineering in humans.
Influence of the cyanine counter anions on a bi-layer solar cell performance
Authors: Malinkiewicz Olga , Grancha Thais , Lenes Martijn , Brine Hicham , Soriano Alejandra , Bolink Henk J.
Published: March 2013

We present normal and inverted solution processed bi-layer solar cells using cationic cyanine dyes as the electron donor and a fullerene as the electron acceptor. The cells exhibit high open circuit voltages up to 1 volt showing the optimal alignment of donor and acceptor energy levels. We demonstrate the large effect that cyanine dye counter ions can have on the energetics of the solar cells and how the S-shaped current density vs. voltage (J-V) curves can be avoided.
Effect of Dispersal of Pd Nanocatalysts on H2 Sensing Response of SnO2 Thin Film Based Gas Sensor
Authors: Verma Manish Kumar , Batra Neha , Tomar Monika , Gupta Vinay
Published: March 2013

SnO2 based sensor structures prepared by rf magnetron sputtering technique have been studied for detecting H2 gas. Pd catalyst was integrated onto the SnO2 thin film in the form of clusters and nano-particles to obtain enhanced sensing response characteristics. The prepared sensor structures have been studied over a temperature range of 50-250°C for sensing response towards 500 ppm H2 gas. The sensor with Pd catalyst dispersed in the form of nanoparticles was found to exhibit an enhanced sensing response of 1.9×103 at a relatively low operating temperature of 150°C with a fast response time of 2 s and recovery time of 65 s towards 500 ppm H2 gas. The origin of enhanced sensing response is identified in the light of the enhanced spill over of H2 gas molecules on the uncovered surface of SnO2 thin film.
Novel Biologically Inspired Nanostructured Scaffolds for Directing Chondrogenic Differentiation of Mesenchymal Stem Cells
Authors: Holmes Benjamin , Castro Nathan J. , Li Jian , Zhang Lijie Grace
Published: March 2013

Cartilage defects, which are caused by a variety of reasons such as traumatic injuries, osteoarthritis, or osteoporosis, represent common and severe clinical problems. Each year, over 6 million people visit hospitals in the U.S. for various knee, wrist, and ankle problems. As modern medicine advances, new and novel methodologies have been explored and developed in order to solve and improve current medical problems. One of the areas of investigation is tissue engineering [1, 2]. Since cartilage matrix is nanocomposite, the goal of the current work is to use nanomaterials and nanofabrication methods to create novel biologically inspired tissue engineered cartilage scaffolds for facilitating human bone marrow mesenchymal stem cell (MSC) chondrogenesis. For this purpose, through electrospinning techniques, we designed a series of novel 3D biomimetic nanostructured scaffolds based on carbon nanotubes and biocompatible poly(L-lactic acid) (PLLA) polymers. Specifically, a series of electrospun fibrous PLLA scaffolds with controlled fiber dimension and surface nanoporosity were fabricated in this study. In vitro hMSC studies showed that stem cells prefer to attach in the scaffolds with smaller fiber diameter or suitable nanoporous structures. More importantly, our in vitro differentiation results demonstrated that incorporation of the biomimetic carbon nanotubes and poly L-lysine coating can induce GAG and collagen synthesis that is indicative of chondrogenic differentiations of MSCs. Our novel scaffolds also performed better than controls, which make them promising for cartilage tissue engineering applications.
Study of the electrical behavior in Intermediate Band-Si junctions
Authors: Pastor D. , Olea J. , del Prado A. , García-Hemme E. , García-Hernansanz R. , González-Pariente L. , Mártil I. , González-Díaz G.
Published: March 2013

In this study we analyze the electrical behavior of a junction formed by an ultraheavily Ti implanted Si layer processed by a Pulsed Laser Melting (PLM) and the non implanted Si substrate. This electrical behavior exhibits an electrical decoupling effect in this bilayer that we have associated to an Intermediate Band (IB) formation in the Ti supersaturated Si layer. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) measurements show a Ti depth profile with concentrations well above the theoretical limit required to the IB formation. Sheet resistance and Hall mobility measurements in the van der Pauw configuration of these bilayers exhibit a clear dependence with the different measurement currents introduced (1µA-1mA). We find that the electrical transport properties measured present an electrical decoupling effect in the bilayer as function of the temperature. The dependence of this effect with the injected current could be explained in terms of an additional current flow in the junction from the substrate to the IB layer and in terms of the voltage dependence in the junction with the measurement current.
Quantitative Defect Analysis on Solar Cells by Laser Beam Induced Current (LBIC) Measurements and 3D Network Simulations
Authors: Nguyen Minh , Schütt Andreas , Carstensen Jürgen , Föll Helmut
Published: March 2013

Measurements with the CELLO (solar cell local characterization) technique in the LBIC (laser beam induced current) mode under dark conditions with various constant bias voltages are used to analyze the lateral distribution, and mean values, of photocurrent response maps. Local solar cell defects such as local shunts were found to have a characteristic bias voltage dependence: At negative and small positive voltages a local shunt resistance gives less current response than the adjacent area. Upon applying higher positive voltages, a transition of the mean value to lower current response and an inversion of the local defect characteristics are found. These results were modeled by a newly introduced three dimensional (3D) equivalent circuit model of a solar cell divided into subcells.

Measurements and simulations of solar cells with various local defects show our method to be a new powerful tool for the quantitative analysis of local solar cell defects.
Effect of Cation Sublattice Ordering on Structure and Raman Scattering of ZnGeN2
Authors: Blanton Eric , He Keliang , Shan Jie , Kash Kathleen
Published: March 2013

The semiconductor ZnGeN2 was grown by a vapor-liquid-solid mechanism. Ordering of the Zn-Ge sublattice with growth temperature and Zn partial pressure was investigated by powder x-ray diffraction and was found to be sensitive to the growth temperature and insensitive, over the range explored, to the Zn and NH3 partial pressures. The degree of disorder on the cation sublattice was observed to correlate with the suppression of predicted Raman peaks and the emergence of phonon density-of-states features.
Ruthenium Oxide Electrodeposition on Titanium Interdigitated Microarrays for Energy Storage
Authors: Armstrong K. , Dinh T.M. , Pech D. , Brunet M. , Gaudet J. , Guay D.
Published: March 2013

The electrodeposition of hydrated ruthenium dioxide (hRuO2) on Ti interdigitated current collectors deposited onto silicon substrate has been investigated with the objective of preparing a high capacitance and high power micro-supercapacitor (µ-SC) device. Ti current collectors were synthesised by typical photolithography processes, and hRuO2 thin films were electrodeposited from ruthenium chloride precursors. Device specific capacitances exceeding 20 mF·cm−2 were obtained, and more than 80 % of that value is retained even at scan rate as high as 1 V∙s−1 in 0.5 M H2SO4. The mean specific power per active surface area of the device is 368 mW·cm−2. The device is stable and 90% of the initial capacity is retained after 105 cycles (1 V potential window). The characteristic response time of the hRuO2 µ-SC is 250 ms, with low ESR (0.61 Ω cm−2) and EDR (0.07 Ω cm−2) values. All these characteristics demonstrate the potential of such µ-SC devices to be part of the next generation of micro-supercapacitors.
Electrical properties of zinc oxide thin films deposited using high-energy H2O generated from a catalytic reaction on platinum nanoparticles
Authors: Yasui Kanji , Yamaguchi Naoya , Nagatomi Eichi , Satomoto Souichi , Kato Takahiro
Published: March 2013

Zinc oxide (ZnO) with excellent crystallinity and large electron mobility was grown on aplane (11-20) sapphire (a-Al2O3) substrates by a new chemical vapor deposition method via the reaction between dimethylzinc (DMZn) and high-energy H2O produced by a Pt-catalyzed H2-O2 reaction. The electron mobility at room temperature increased from 30 cm2/Vs to 189 cm2/Vs with increasing film thickness from 0.1 μm to approximately 3 μm. Electron mobility increased significantly with decreasing temperature to approximately 110 – 150 K, but decreased at temperatures less than 100 K for films greater than 500 nm in thickness. On the other hand, the mobility hardly changed with temperature for films lesser than 500 nm in thickness. Based on the dependence of the electrical properties on the film thickness, the ZnO films grown on a-Al2O3 substrates are considered to consist of an interfacial layer with a high defect density (degenerate layer) generated due to a large lattice mismatch between ZnO and Al2O3 substrates and an upper layer with a low defect density.
Bacterial Adhesion to Nanomodified Surfaces: Dynamic Flow Effects onS. aureusandP. aeruginosa
Authors: Machado Mary C. , Tarquinio Keiko M. , Webster Thomas J.
Published: March 2013

Ventilator associated pneumonia (VAP) is a serious and costly clinical problem. Specifically, receiving mechanical ventilation over 24 hours increases the risk of VAP and is associated with high morbidity, mortality and medical costs. Cost effective endotracheal tubes (ETTs) that are resistant to bacterial infection would help to prevent this problem. The objective of this study was to determine differences in bacterial growth on nanomodified and unmodified ETTs under dynamic airway conditions. A bench top model based upon the general design of Hartmann et al. (1999) was constructed to test of the effectiveness of nanomodified ETTs under the airflow conditions present in the airway. Twenty-four hour studies performed in a dynamic flow chamber showed a marked difference in the biofilm formation on different areas of unmodified tubes. Areas where tubes were curved, such as at the entrance to the mouth and the connection between the oropharynx and the larynx, seemed to collect the largest amount of biofilm.

The biofilm formation on ETTs in the airflow system after 24 hours showed a large difference depending upon where tubes were oriented within the apparatus. This illustrates the importance of dynamic flow on biofilm formation in pediatric ETTs. It is of particular interest that increased biofilm density on both unmodified and nanomodified tubes appeared to occur at curves in the tube where changes in flow pattern occurred. This emphasizes the need for more accurate models of airflow within pediatric ETTs, suggesting that not only does flow affect pressure gradients along the tube, but in fact, determines the composition of the film itself. More testing is needed to determine the effects of biofilm formation on the efficiency of ETT under airflow, however this study provides significant evidence for nanomodification alone (without the use of antibiotics) to decrease bacteria function.
Copper oxide nanoparticles for thin film photovoltaics
Authors: Nuys Maurice , Flohre Jan , Leidinger Christine , Köhler Florian , Carius Reinhard
Published: March 2013

Commercially available tenorite (CuO) nanoparticles (NPs) were investigated in particular with respect to their suitability for photovoltaic applications. NPs with a diameter of about 30 nm were step wise annealed up to 1000°C in nitrogen atmosphere. The influence of the annealing treatment on the structural and electronic properties was investigated by Raman, photoluminescence (PL) and photothermal deflection spectroscopy (PDS) as well as X-ray diffraction measurements. Size, shape, and phase of the untreated NPs are analyzed by TEM measurements. The PL and PDS results show a strong increase of the tenorite band edge emission at about 1.3 eV accompanied by a decreasing sub gap absorption with increasing annealing temperature up to 700°C. According to literature, a phase transition from tenorite to cuprite (Cu2O) was expected and observed after annealing at 800°C. Strong cuprite band edge emission at about 2 eV accompanied by very weak defect and possibly tenorite band edge emission was found for samples annealed at 800°C and 1000°C.
Real-Time Investigation of NanoFET Current Surge Capability During Heavy Ion Irradiation
Authors: Xie Kan , Hartz Steven Allen , Ayres Virginia M. , Liu Zhun , Jacobs Benjamin W. , Baumann Thomas , Ronningen Reginald M. , Zeller Albert F. , Tupta Mary Anne
Published: March 2013

The real-time electronic performance of a gallium nitride nanowire-based field effect transistor was investigated at five-minute intervals over thirty minutes of continuous irradiation by Xenon-124 relativistic heavy ions. An initial current surge that resulted in device improvement rather than device failure was observed. The current surge, and subsequent electronic behavior, was modeled using a combined thermionic emission-tunnelling approach, leading to information about barrier height, carrier concentrations, expected temperature behavior, and tunnelling.
Electrical Signature of Ion-Implantation Induced Defects in n-Silicon in the Defect Cluster Regime Studied using DLTS and Isothermal Transient Spectroscopies
Authors: Singh Samarendra P. , Rao Vineet , Mohapatra Y. N. , Rangan Sanjay , Ashok S.
Published: March 2013

We study electrical signature of defect clusters in KeV Ar ion-implanted n-silicon using Deep Level Transient Spectroscopy (DLTS) and isothermal capacitance spectroscopies such as time analyzed transient spectroscopy (TATS) and high resolution Laplace-DLTS. The samples are annealed at relatively low temperatures of 350 °C - 600 °C at which defect clusters are known to form and evolve. Contrary to the view that few dominant point-defect like traps are associated with defect clusters, our results show that the band gap may be replete with bands of multiple trap states; however their occupation and hence observation depends on experimental conditions dictated by dynamics of carrier capture and emission at these traps. Charge redistribution among multiple states and deepening of effective emission energy with capture are shown to be commonly occurring at these defects. Isothermal transient spectroscopy is shown to be appropriate tool for recognition of some of these features.
Formation and Properties of Three Copper Pairs in Silicon
Authors: Estreicher S.K. , West D. , Pruneda J.M. , Knack S. , Weber J.
Published: March 2013

Copper in silicon is a feared contaminant in device processing. It diffuses quickly as an interstitial and forms electrically active precipitates that are difficult to dissolve. Several complexes assigned to copper pairs have been observed but have yet to be unambiguously identified and fully characterized. We present the results of joint theoretical-experimental studies of several pair structures. The theoretical work involves ab-initio molecular-dynamics simulations, and the results include configurations, binding energies, electronic structures, vibrational modes and formation dynamics. The experimental work combines electrical and optical techniques. One characteristic of the photoluminescence spectra is the presence of phonon replicas that imply the existence of very similar low-frequency and localized vibrational modes in two distinct copper pairs. These modes are theoretically identified.
Reduction of pier scour using bed suction and jet injection
Authors: Soltani-Gerdefaramarzi Somayeh , Afzalimehr Hossein , Chiew Yee-Meng , Gallichand Jacques
Published: March 2013

The influence of a combined system of jet injection through the pier and bed suction on the reduction of local scour around a circular pier was investigated in a laboratory flume. Experiments were conducted for two water depths (10·5 and 28 cm) under 1-jet and 3-jet injection and different angles between the jets, with bed suction rate Qs/Q0 = 2%, in turbulent flow and clear-water scouring conditions. The results show that the bed suction modifies the effect of jet scouring and reduces the local scour and sediment transport at the pier (36% for scour depth, 25 and 42% for the area and volume of scour hole). The maximum reduction of the scour depth was about 50% (about 20, 39 and 39% for the area, volume and the upstream slope of the scour hole respectively) in the best configurations for a combined countermeasure.
Large Bore Expandable Liner Hangers for Offshore and Deepwater Applications Reduces Cost and Increases Reliability: GOM Case History
Authors: McCormick John , Carter Alexis , Johnson Rick
Published: March 2013

Reducing rig time and material costs for offshore wells is critical to a project's financial profitability. With the dramatic increase in the number of deepwater wells, new technologies and methods are needed to quickly and reliably complete wells. A case history of five deepwater large bore expandable liner hangers (ELHs) from late 2011 through the first half of 2012 in the Gulf of Mexico (GOM) show consistent material cost savings, reduced installation time, improved reliability, and increased versatility over conventional liner hanger systems. Four of these ELH systems were run off drill ships and one off a platform. A picture of the large bore ELH system is shown in Fig. 1.

The technological advances of ELH systems have increased well life and improved safety during liner installations over traditional systems. Sealing capabilities with expandable systems have evolved beyond conventional tools and the smooth radial flowpaths allow for greater ease of installation. A series of redundant sealing elements provide a gas tight liner top seal. Also, with the ELH system, rotation and reciprocation while cementing are possible.

This paper will describe offshore wells and the common problems associated with running intermediate liners. Expandable liner hanger technology will be explored to increase operator awareness of this beneficial technology. A comparison of ELH technology and the conventional systems in the same field are described within this paper.
Well Bore Collision Avoidance and Interceptions - State of the Art
Authors: de Wardt John P , Mullin Steve , Thorogood John L , Wright John , Bacon Robert
Published: March 2013

This paper highlights key knowledge that was shared at the SPE Collision Avoidance and Well Interceptions Applied Technology Workshop held in Inverness, September 2012. It has been written to raise awareness of critical issues concerning well bore collisions and interceptions.

Planning to ensure well collisions do not occur during drilling is a complex and demanding task which is often not given the high priority it requires in drilling programs. Assumptions are made of the validity and accuracy of historical data which is unfounded. Conversely, planning well interceptions when required in operations such as relief wells / drainage intercept wells requires a sound working knowledge of wellbore positioning technologies and techniques.

Well bore interceptions and proximity placement are becoming critical applications for development of some reservoirs, specifically tar sands and coal bed methane. Well bore collision avoidance is entering the everyday skills requirement of drilling engineers as they plan more infill wells and more cluster (pad) drilling. Ultimately, demonstrating knowledge of the bore hole position during the whole drilling process is becoming more of a regulatory requirement that demands greater understanding by the drilling engineering community and drilling / asset managers. Are drilling engineers trained, competent and adhering to procedures designed to manage the intricacies of well bore surveying requirements as applied to collision avoidance and well interceptions?

The workshop covered the topic under the following headings:

Survey database integrity. Collision avoidance management. Practical directional drilling. Relief well design. Interception techniques.

The outcome of the workshop was to emphasize that wellbore collisions must be treated as high risk events with serious consequences that must be managed through systematic survey management procedures. Borehole position errors are a critical input to subsurface modeling and can have a major impact on field economics. Several members of the workshop committee are also members of the SPE Wellbore Positioning Technical Section that has published two SPE papers providing the industry with the ellipse of uncertainty error models commonly referred to as the Industry Steering Committee on Wellbore Survey Accuracy (ISCWSA) models.
The Evolution of Wired Drilling Tools: A Background, History and Learnings from the Development of a Suite of Drilling Tools for Wired Drillstrings
Authors: Craig A. D. , Jackson T. A. , Ramnarace D. , Schultze R. , Briscoe M.
Published: March 2013

This paper will summarize the development of a range of drilling tools for use in a wired drillstring. The paper will focus on the history and learnings from the engineering design, field use and commercialization of wired conventional drilling tools including jars and underreamers as well as the development of an advanced drilling dynamics measurement capable of transmitting downhole data through the wired drillpipe network.

Wired drillstrings enable broadband bi-directional telemetry and along-string measurement capabilities for drilling and other well operations. Communication across the drillstring is achieved through the use of passive inductive coils placed in the pin and box shoulders connected by an armored coaxial cable which spans the length of the component.

Connection of conventional Measurement While Drilling (MWD) and Logging While Drilling (LWD) tools to the wired drillstring network requires that all components above these tools be wired as per this process. In a typical BHA this will include basic components such as Heavy Weight Drill Pipe (HWDP), drill collars and various subs but more internally complicated components such as drilling jars and underreamers.

The development of wired variants of these tools has required innovative engineering solutions, field testing and design revisions to ensure a reliable tool performance. This paper will summarize this process for both the development of a range of wired drilling jars and a wired underreamer.

The paper will then summarize the development of an advanced drilling dynamics measurement tool. The tool features a full suite of dynamics measurement including shock & vibration, downhole RPM, downhole torque, Weight on Bit (WOB) and bending moment. With telemetry provided by a wired drillstring this tool has the capability to provide real-time data with quality and definition orders of magnitude higher than conventional drilling dynamics tools. A series of examples of real-time data provided by this tool will also be presented and discussed.
Detect Kicks Prompted by Losses and Direct Measurement Well Control Method through Networked Drillstring with Along String Pressure Evaluation
Authors: Veeningen Daan
Published: March 2013

Traditional well control methods rely on surface measurements to identify a kick or wellbore influx. While most well control events occur during underbalanced conditions, an influx may be prompted by major vugular losses, typically caused by a carbonate vug. During such incidents, overbalanced drilling conditions plunge and the bottomhole pressure equalizes to pore pressure in the vug. An influx at surface is never experienced, as the annulus fluid level drops. Even filling the annulus does not prevent the BHP decrease and the resulting wellbore pressure is then approximately equal to the vug pore pressure minus the hydrostatic head. Since the drilling fluid gradient exceeds the formation pressure gradient, an underbalance is created along the exposed carbonate wellbore section. Hydrocarbons may enter, flowing down towards the vug along with the displacing fluid, until the wellbore pressure is equal to the formation pressure.

This paper describes efficient detection of well control events, both in underbalanced and overbalanced conditions, which is especially relevant for deepwater operations as the reaction time is significantly less than with surface BOPs. A methodology is offered to detect the annulus fluid level in conditions of unknown hydrostatic column height and fluid density through the use of discrete annular pressure acquisition along a networked drillstring. The downhole real time pressure evaluation also provides for monitoring of the gas migration to manage annular filling while losses continue to be experienced. Further, the ‘direct measurement method’ is offered for well control based on constant bottomhole pressure through downhole pressure measurements independently from surface measurements.
Basis of Design and Specifications for Shallow Water Arctic MODU for Year-round Operation, Development and Exploration
Authors: Shafer R. S. , Noble P. N. , Cheung T. O. , Chow Y. Y. , Quah M. , Foo K. S. , Wang C. D. , Perry M. J.
Published: March 2013

In Arctic offshore areas where exploration and production of hydrocarbons may occur, a substantial portion lies in water depths less than 50 meters. Currently there are no MODU's which can drill all different well types, production and exploration, over a wide range of water depths from 10 m to 50 m, ice conditions, and facilitate alternative development plans, using wellhead platforms. ConocoPhillips Company, in cooperation with Keppel, Offshore and Marine and Technology Centre, have developed a basis of design and specifications for a Self elevating Arctic Mobile Offshore Drilling Unit (MODU) for use in these water depths capabilities to drill a wide range of wells.

Economics require that a new build Arctic MODU be highly productive and operate nearly year-round. The Basis of Design and specifications result in a MODU that would have a wide range of application, be highly productive, and make alternative field development concepts viable.

The focus of this paper is to detail major items that impact the size, weight, and configuration of an Arctic MODU. This will result in a conceptual unit design that will be used in determine ice loads, layout, and structural design of the Arctic MODU.