bluuebunny/crossref_metadata_2025 huggingface dataset:
Emergency cricothyrotomy – a systematic review
Authors: Langvad Sofie , Hyldmo Per Kristian , Nakstad Anders Rostrup , Vist Gunn Elisabeth , Sandberg Marten
Published: May 2013

Background

An emergency cricothyrotomy is the last-resort in most airway management protocols and is performed when it is not possible to intubate or ventilate a patient. This situation can rapidly prove fatal, making it important to identify the best method to establish a secure airway. We conducted a systematic review to identify whether there exists superiority between available commercial kits versus traditional surgical and needle techniques.

Methods

Medline, EMBASE and other databases were searched for pertinent studies. The inclusion criteria included manikin, animal and human studies and there were no restrictions regarding the professional background of the person performing the procedure.

Results

In total, 1,405 unique references were identified; 108 full text articles were retrieved; and 24 studies were included in the review. Studies comparing kits with one another or with various surgical and needle techniques were identified. The outcome measures included in this systematic review were success rate and time consumption. The investigators performing the studies had chosen unique combinations of starting and stopping points for time measurements, making comparisons between studies difficult and leading to many conflicting results. No single method was shown to be better than the others, but the size of the studies makes it impossible to draw firm conclusions.

Conclusions

The large majority of the studies were too small to demonstrate statistically significant differences, and the limited available evidence was of low or very low quality. That none of the techniques in these studies demonstrated better results than the others does not necessarily indicate that each is equally good, and these conclusions will likely change as new evidence becomes available.
Are patients with inflammatory eye disease treated with systemic immunosuppressive therapy at increased risk of malignancy?
Authors: Yates William B , McCluskey Peter J , Wakefield Denis
Published: May 2013

The purpose of this study is to review the literature on the risk of malignancy in patients with inflammatory eye disease (IED) treated with systemic immunosuppressive (IS) therapy. Relevant databases in transplant medicine, autoimmune diseases and literature regarding uveitis and scleritis were reviewed. Literature with regards systemic IS therapy in transplant recipients and patients with autoimmune diseases revealed a significant increase in malignancies, especially non-melanocytic skin cancers and lymphomas. Studies of patients with IED were limited in number and scope, with no studies adequately evaluating the incidence of malignancy in these patients. Difficulties associated with the evaluation of the risk of malignancy associated with IS therapy in patients with IED include the heterogeneity of the disease and treatment regimens as well as the low frequency of IED, its variable severity and the lack of adequate long-term follow-up studies. Systemic IS therapy is an important therapeutic option in the treatment of patients with severe IED. A well-designed, comprehensive, multi-centre long-term follow-up study is required to evaluate the risk of malignancy in patients with specific IED diseases treated with defined systemic IS therapy. Until such evidence is available, we recommend the adoption of preventative strategies to help minimise the risk of malignancy in such patients.
Cyclosporine-assisted adipose-derived mesenchymal stem cell therapy to mitigate acute kidney ischemia–reperfusion injury
Authors: Chen Yen-Ta , Yang Chih-Chau , Zhen Yen-Yi , Wallace Christopher Glenn , Yang Jenq-Lin , Sun Cheuk-Kwan , Tsai Tzu-Hsien , Sheu Jiunn-Jye , Chua Sarah , Chang Chia-Lo , Cho Chung-Lung , Leu Steve , Yip Hon-Kan
Published: May 2013

Introduction

This study tested the hypothesis that cyclosporine (CsA)-supported syngeneic adipose-derived mesenchymal stem cell (ADMSC) therapy offered superior attenuation of acute ischemia–reperfusion (IR) kidney injury to either therapy alone.

Methods

Adult Sprague–Dawley rats (n = 40) were equally divided into group 1 (sham controls), group 2 (IR injury), group 3 (IR + CsA (20 mg/kg at 1 and 24 hours after procedure)), group 4 (syngeneic ADMSC (1.2×106) at 1, 6 and 24 hours after procedure), and group 5 (IR + CsA-ADMSC).

Results

By 72 hours after the IR procedure, the creatinine level and the ratio of urine protein to creatinine were highest in group 2 and lowest in group 1, and significantly higher in groups 3 and 4 than in group 5 (all P <0.05 for inter-group comparisons), but showed no differences between groups 3 and 4 (P >0.05). The inflammatory biomarkers at mRNA (matrix metalloproteinase-9, RANTES, TNF-α), protein (TNF-α, NF-κB, intercellular adhesion molecule-1, platelet-derived growth factor), and cellular (CD68+) levels of IR kidney showed a similar pattern compared with that of creatinine in all groups (all P <0.05 for inter-group comparisons). The protein expressions of oxidative stress (oxidized protein), reactive oxygen species (NADPH oxidases NOX-1, NOX-2), apoptosis (Bcl-2–associated X protein, caspase-3 and poly(ADP-ribose) polymerase) and DNA damage (phosphorylated H2A histone family member X-positive, proliferating cell nuclear antigen-positive cells) markers exhibited a pattern similar to that of inflammatory mediators amongst all groups (all P <0.05 for inter-group comparisons). Expressions of antioxidant biomarkers at cellular (glutathione peroxidase, glutathione reductase, heme oxygenase-1 (HO-1)) and protein (NADPH dehydrogenase (quinone)-1, HO-1, endothelial nitric oxide synthase) levels, and endothelial progenitor cell markers (C-X-C chemokine receptor type 4-positive, stromal cell-derived factor-1α-positive) were lowest in groups 1 and 2, higher in groups 3 and 4, and highest in group 5 (all P <0.05 for inter-group comparisons).

Conclusion

Combination therapy using CsA plus ADMSCs offers improved protection against acute IR kidney injury.
Innovative activity of enterprises as a measure of competitiveness of Russia
Authors: Кальянов  , Kalyanov Aleksandr
Published: May 2013

It is shown that an increase in the competitiveness of Russia is impossible without an increase in the prestigious science and technology and innovation, and its inclusion among the top priorities. An important form of support from the public authorities should be to develop the legal framework of innovation and adoption of legal acts aimed at creating an enabling environment for

innovative economic development. This should include the evelopment and improvement of the legislation in order to create a unified state policy innovation and creating favorable conditions for the development of science, technology and innovation, including its stimulation.
Tendencies of development of the world energy
Authors: Фомичева  , Fomicheva Irina
Published: May 2013

The paper presents the dynamics and structure of the previous and the future of global energy development for the period up to 2050. Analyzed the structural changes in the global energy balance. Identify priority areas of the global electricity.
Estimating Second Order Probability Beliefs from Subjective Survival Data
Authors: Hudomiet Péter , Willis Robert J.
Published: May 2013

Based on subjective survival probability questions in the Health and Retirement Study (HRS), we use an econometric model to estimate the determinants of individual-level uncertainty about personal longevity. This model is built around the modal response hypothesis (MRH), a mathematical expression of the idea that survey responses of 0%, 50%, or 100% to probability questions indicate a high level of uncertainty about the relevant probability. We show that subjective survival expectations in 2002 line up very well with realized mortality of the HRS respondents between 2002 and 2010. We show that the MRH model performs better than typically used models in the literature of subjective probabilities. Our model gives more accurate estimates of low probability events and it is able to predict the unusually high fraction of focal 0%, 50%, and 100% answers observed in many data sets on subjective probabilities. We show that subjects place too much weight on parents' age at death when forming expectations about their own longevity, whereas other covariates such as demographics, cognition, personality, subjective health, and health behavior are underweighted. We also find that less educated people, smokers, and women have less certain beliefs, and recent health shocks increase uncertainty about survival, too.
Components of Portfolio Value of Information
Authors: Zan Kun , Bickel J. Eric
Published: May 2013

Decision analysis is often employed in portfolio management. The portfolio management process consists primarily of valuation (including uncertainty quantification or risk assessment) and prioritization/selection, which are based on the results of valuation. In this paper, we quantify the relative value of these components using a value of information (VOI) framework. Specifically, we quantify the VOI that stems from the ability to better prioritize projects and the VOI that comes from the ability to exclude projects. We identify conditions under which prioritization is the primary value driver in portfolio settings.
Surgery of the small intestine in dogs and cats
Authors: Murgia Daniela
Published: May 2013

Part 1: surgical principles and surgical conditions: Patients with small intestinal abnormalities are at risk for dehydration, acid-base and electrolyte imbalances, and should be stabilised before surgery. During surgery, the bowel should be handled gently using atraumatic instrumentation and suitable suture material.
Backyard pigs: part 1 – animal husbandry considerations
Authors: Duncanson Graham R
Published: May 2013

This article discusses the keeping of small groups of pigs, their breeds and the reasons for keeping them. The role of the veterinary practitioner is outlined, together with the input required from the practice. A protocol for an initial visit is suggested and the legal requirements to be followed by the client keeping backyard pigs are laid out in detail.
Small Animal Review
Authors: Tennant Bryn
Published: May 2013

Introduction

Increased dietary copper availability may impact on the development of chronic hepatitis in Labrador Retrievers.
Staying safe on farms
Authors: Bazeley Katrine , Davies Andrew
Published: May 2013

Following the severe injury of a colleague, this article discusses ways that the farm animal clinician can reduce the risks, both to themselves and to farm staff and animals, while working on farms. Risk assessment is not just a tedious piece of red tape but as essential as scrubbing up before surgery, and should be undertaken before any job is embarked on. Risks cannot be eliminated, but can be kept to a minimum.
Prognosis of joint infections in growing and adult sheep: a 3-year study
Authors: Scott Phil
Published: May 2013

In a 3-year study of joint infections, undertaken by the author, bacterial infection of a single joint caused severe lameness in 39 sheep older than 6 months; another 15 sheep had polyarthritis consistent with erysipelas. All cases had proven unresponsive to antibiotic therapy administered by the farmer. A penetration wound was responsible for single cases of septic stifle, shoulder, and fetlock; the remaining 36 cases of single joint infection were presumed to have originated from a bacteraemia. Radiography added little additional information except to reveal origin of infection from a growth plate (five cases), and osteophyte formation and erosion of articular surfaces in neglected cases. Necropsy findings were characterised by pronounced synovial membrane proliferation and, in neglected cases, erosion of articular cartilage. Most infected joints contained only small amounts of a pannus. A single treatment success was achieved with arthroscopy and joint lavage from four cases that had been lame for less than 1 week. Sheep with joint infections that remain lame after an appropriate course of antibiotic treatment should be euthanased for welfare reasons.
Fourth branchial arch defect: a case study
Authors: Barakzai Safia
Published: May 2013

Horses that present with abnormal upper respiratory noise at exercise can have a myriad of different laryngeal and pharyngeal structures collapsing into the airway, and exercising endoscopy provides the only way of providing a definitive diagnosis (or diagnoses in the case of composite collapse). However, a thorough clinical examination, endoscopic examination at rest and other ancillary diagnostic techniques can be very useful in some cases. This case study describes the clinical and endoscopic findings of a horse with suspected fourth branchial arch defect (4-BAD), a syndrome in which laryngeal palpation, radiography and ultrasound can all be very useful in addition to resting and exercising endoscopy when making a diagnosis.
Equine Review
Authors: Rendle David
Published: May 2013

Introduction:

This edition of Equine Review considers papers on headshaking, placebo effects and grass sickness.
Age-Specific Survival of Tundra Swans on the Lower Alaska Peninsula
Authors: Meixell Brandt W. , Lindberg Mark S. , Conn Paul B. , Dau Christian P. , Sarvis John E. , Sowl Kristine M.
Published: May 2013

The population of Tundra Swans (Cygnus columbianus columbianus) breeding on the lower Alaska Peninsula represents the southern extremity of the species' range and is uniquely nonmigratory. We used data on recaptures, resightings, and recoveries of neck-collared Tundra Swans on the lower Alaska Peninsula to estimate collar loss, annual apparent survival, and other demographic parameters for the years 1978– 1989. Annual collar loss was greater for adult males fitted with either the thinner collar type (0.34) or the thicker collar type (0.15) than for other age/sex classes (thinner: 0.10, thicker: 0.04). The apparent mean probability of survival of adults (0.61) was higher than that of immatures (0.41) and for both age classes varied considerably by year (adult range: 0.44–0.95, immature range: 0.25–0.90). To assess effects of permanent emigration by age and breeding class, we analyzed post hoc the encounter histories of swans known to breed in our study area. The apparent mean survival of known breeders (0.65) was generally higher than that of the entire marked sample but still varied considerably by year (range 0.26–1.00) and indicated that permanent emigration of breeding swans was likely. We suggest that reductions in apparent survival probability were influenced primarily by high and variable rates of permanent emigration and that immigration by swans from elsewhere may be important in sustaining a breeding population at and near Izembek National Wildlife Refuge.
Morphofunctional effects of mitotane on mitochondria in human adrenocortical cancer cells
Authors: Poli Giada , Guasti Daniele , Rapizzi Elena , Fucci Rossella , Canu Letizia , Bandinelli Alessandra , Cini Nicoletta , Bani Daniele , Mannelli Massimo , Luconi Michaela
Published: May 2013

At present, mitotane (MTT) represents the first-line pharmacological approach for the treatment of advanced adrenocortical carcinoma (ACC). Despite clear evidence that the drug can reduce the clinical signs of steroid excess in secreting ACC, the mechanism mediating the possible toxic effect of MTT on tumor cells still remains obscure. This study investigated the intracellular events underlying the toxic effect of MTT by studying qualitative and quantitative alterations in mitochondrial morphology and functions in human adrenocortical cancer cell lines, H295R and SW13. Increasing concentrations of MTT resulted in rapid intracellular accumulation and conversion of the drug. Cytostatic and cytotoxic effects were evident at doses corresponding to the therapeutic window (30–50 μM) through an apoptotic mechanism involving caspase 3/7. Electron microscopic analysis of cell mitochondria displayed MTT-induced dose- and time-dependent alterations in the morphology of the organelle. These alterations were characterized by a marked swelling and a decrease in the number of respiratory cristae, accompanied by a significant depolarization of the mitochondrial membrane potential, finally leading to the disruption of the organelle. A drastic reduction of oxygen consumption was observed due to mitochondrial membrane damage, which was accompanied by a decrease in the levels of VDAC1 integral membrane channel. These findings contribute to better understand the intracellular mechanism of action of MTT in ACC cells, showing that its cytotoxic effect seems to be mainly mediated by an apoptotic process activated by the disruption of mitochondria.
Coagulase Negative Staphylococci in the Neonatal Intensive Care Unit: Are We Any Smarter?
Authors: Nash Colleen , Chu Alison , Bhatti Micah , Alexander Kenneth , Schreiber Michael , Hageman Joseph R.
Published: May 2013

Coagulase negative staphylococci are increasingly common organisms isolated in the evaluation of neonates with sepsis. However, there is a lack of consensus on the definition of true infection and the criteria for treatment. This article presents clinically useful methods to distinguish true infection from contamination. Additionally, we describe clinically relevant virulence factors contributing to the pathogenicity of various species. Knowing these virulence factors may help to stratify patient risk for serious infection. There are inconsistent data regarding the clinical importance of coagulase negative staphylococcal infections in the neonatal population. This inconsistency highlights the importance of establishing a consensus for the diagnosis and treatment of these infections in both the clinical and research arenas.
Culture Negative Sepsis and Systemic Inflammatory Response Syndrome in Neonates
Authors: Piantino Jessica H. , Schreiber Michael D. , Alexander Kenneth , Hageman Joseph
Published: May 2013

Sepsis is a common and potentially devastating occurrence in NICUs. Sepsis is defined as the constellation of findings making up the systemic inflammatory response syndrome plus an infection. Newer studies now suggest that treatment of infants who have nonspecific signs of illness with prolonged antibiotics can lead to serious complications. The complexities of practicing medicine in the NICU sometimes limit our ability to secure a diagnosis of culture proven sepsis. The administration of antibiotics until bacterial infection can be reasonably ruled out should occur concurrently with evaluations of other plausible noninfectious diagnoses.
Perinatal Group B Streptococcal Infections: Current Status and Future Directions
Authors: Tumbaga Purificacion F. , Philip Alistair G.S.
Published: May 2013

Group B Streptococcus (GBS) remains the leading cause of neonatal sepsis and meningitis in the United States, despite a dramatic 80% decline in the incidence of early-onset GBS disease with intrapartum antibiotic prophylaxis (IAP). Perinatal GBS disease persists and the incidence of late-onset GBS disease is unchanged. Maternal immunization with conjugate vaccines for the most prevalent serotypes may have a role in further reducing early-onset disease but should have greater impact on late-onset disease. In addition, it could both reduce the problem of antibiotic resistance and potentially prevent adverse neuro-developmental outcomes.

Universal vaccination of pregnant women or adolescent women could confer protection beginning in the third trimester, with transplacental transfer of maternal antibodies, extending protection into early infancy. However, this strategy would be of limited benefit to preterm infants, particularly those born before 32 weeks’ gestation. Universal screening of pregnant women at 35 to 37 weeks’ gestation for GBS colonization and providing IAP remain the mainstays for perinatal disease prevention.

In this era of widespread IAP, neonatal management is challenging in the asymptomatic at-risk newborn population. Further research is needed to establish sound diagnostic aids, avoid antibiotic misuse, and prevent serious neurologic sequelae.
Collaborative Chronic Care Networks (C3Ns) to Transform Chronic Illness Care
Authors: Margolis Peter A. , Peterson Laura E. , Seid Michael
Published: May 2013

Despite significant gains by pediatric collaborative improvement networks, the overall US system of chronic illness care does not work well. A new paradigm is needed: a Collaborative Chronic Care Network (C3N). A C3N is a network-based production system that harnesses the collective intelligence of patients, clinicians, and researchers and distributes the production of knowledge, information, and know-how over large groups of people, dramatically accelerating the discovery process. A C3N is a platform of “operating systems” on which interconnected processes and interventions are designed, tested, and implemented. The social operating system is facilitated by community building, engaging all stakeholders and their expertise, and providing multiple ways to participate. Standard progress measures and a robust information technology infrastructure enable the technical operating system to reduce unwanted variation and adopt advances more rapidly. A structured approach to innovation design provides a scientific operating system or “laboratory” for what works and how to make it work. Data support testing and research on multiple levels: comparative effectiveness research for populations, evaluating care delivery processes at the care center level, and N-of-1 trials and other methods to select the best treatment of individual patient circumstances. Methods to reduce transactional costs to participate include a Federated IRB Model in which centers rely on a protocol approved at 1 central institutional review board and a “commons framework” for organizational copyright and intellectual property concerns. A fully realized C3N represents a discontinuous leap to a self-developing learning health system capable of producing a qualitatively different approach to improving health.
After Dr Google: Peer-to-Peer Health Care
Authors: Fox Susannah
Published: May 2013

Although the majority of US adults has Internet access and gathers health information online, the Internet does not replace clinicians. People rate health professionals as their top source for technical questions such as diagnosis and treatment, but nonprofessionals (eg, friends and family) are rated higher for emotional support and quick remedies. For their most recent health issue, 21% of adults say they turned to others who have the same health condition; evidence of people’s interest in connecting with and learning from each other. People living with chronic diseases (and their caregivers) are especially likely to say they look online for peer advice. They are pioneering new ways of pursuing health by banding together and sharing knowledge; so-called peer-to-peer health care. Practical tips from fellow patients and caregivers can have far-reaching implications for clinical outcomes. As a parent of a chronically ill child observed: “We all work collaboratively, but I notice that my doctor doesn’t. After I’ve talked with my community online, I go back to him and ask, ‘What do your colleagues say about this issue?’ And it’s clear it didn’t occur to him to ask them.” Clinicians might do well to look into online patient communities and consider recommending them as resources for their patients. Clinicians might look at patient networks as a model for their own collaborative learning process as well. Linking the expertise of patients, families, and clinicians holds promise for further improving care and outcomes.
Dynamic Infrared Electro-optic Response of Soluble Organic Semiconductors in Thin Film Transistors
Authors: Bittle Emily G. , Brill Joseph W. , Straley Joseph P.
Published: May 2013

We use a frequency-dependent electro-optic technique to measure the hole mobility in small molecule organic semiconductors, such as 6,13 bis(triisopropylsilylethynyl)-pentacene. Measurements are made on semiconductor films in bottom gate, bottom contact field-effect transistors (FETs.) Because of the buried metal layer effect the maximum response, due to absorption in the charge layer, will be for a dielectric film ∼ 1/4 of a wavelength (in the dielectric) (e.g. ∼ 1 micron thick in the infrared.) Results are presented for FETs prepared with both spin-cast polymer and alumina dielectrics prepared by atomic layer deposition. At low frequencies the results are fit to solutions to a non-linear differential equation describing the spatial dependence of flowing charge in the FET channel, which allows us to study multiple crystals forming across one set of drain-source contacts. FETs prepared on alumina dielectrics show interesting deviations from the model at high frequencies, possibly due to increased contact impedance.
Ferroelectric Memoirs
Authors: Scott J. F.
Published: May 2013

A personal view of ferroelectrics and multiferroics research is given with suggestions for future work, emphasizing nano-dynamics.
Production and characterization of Al 2024 matrix composites reinforced with β-Al3Mg2complex metallic alloy particles
Authors: Wang Xiaorui , Scudino Sergio , Eckert Jürgen
Published: May 2013

In this work, composites consisting of the Al 2024 matrix reinforced with β-Al3Mg2particles have been produced by powder metallurgy with the aim of increasing the strength of the matrix and, at the same time, reducing the density of the material. The β-Al3Mg2phase represents an ideal candidate as reinforcement in lightweight composites due to its low density and high-temperature strength. The β-Al3Mg2reinforcement remarkably improves the mechanical properties of the 2024 matrix. In particular, the composite with 20 vol.% reinforcement display yield and compressive strengths exceeding that of the unreinforced matrix by about 120 and 180 MPa, while retaining appreciable plastic deformation of about 30 %. The strength of the material is further increased for the samples with 30 and 40 vol.% of β-Al3Mg2phase, however, the composites show reduced plastic deformation of 11 and 4.5 %. Furthermore, the addition of the low-density β-Al3Mg2particles decreases the density of the materials below that of the unreinforced 2024 matrix, considerably increasing the specific strength of the composites.
Structural and Electronic Properties of Cu64Zr36 BMG by ab initio Molecular Dynamics
Authors: Galván-Colín Jonathan , Valladares Ariel A. , Valladares Alexander , Valladares Renela M.
Published: May 2013

Much attention has been given to bulk metallic glasses (BMG) in recent years, particularly those based on binary alloys due to the simplicity of their atomic composition. Although efforts to understand the atomistic features that give rise to their exceptional properties have been made, the electronic and vibrational properties have been disregarded. We undertook the task of simulating the Cu64Zr36 glassy metal using a supercell with 108 atoms and a different simulational approach: the undermelt-quench approach [1]. The structure was characterized by means of the radial (pair) distribution function and the bond-angle distribution and the electronic density of states was calculated. We find that our results agree well with experimental data.
Photocatalytic TiO2 Macroscopic Fiber Obtained through Integrative Chemistry
Authors: Kinadjian Natacha , Le Bechec Mickael , Pigot Thierry , Dufour Fabien , Durupthy Olivier , Bentaleb Ahmed , Prouzet Eric , Lacombe Sylvie , Backov Rénal
Published: May 2013

Photocatalytic properties of titanium oxide depend on the material size and shape, which can favour a higher interaction between reactants and catalyst. Most of the studies reported until now, show that reducing size down to the nanoscale increases the photocatalytic efficiency. We demonstrate that a multiscale shape design, integrating surface roughness, particle shape, and material 1D processing and orientation, can favour photocatalytic properties in the solid-gas regime, especially mineralization (conversion into CO2), when the material hierarchical 1D orientation is combined with unidirectional gas flow. Several materials with hierarchical structure were prepared and characterized. They have been tested for the photocatalytic mineralization of gaseous acetone, and compared with commercial catalysts. Our study reveals that a suitable combination of multiscale design can favour high mineralization.
Microstructural Effects on the Shock Compression Response of Cold-Rolled Ni/Al Multilayers
Authors: Specht Paul E. , Thadhani Naresh , Weihs Timothy P.
Published: May 2013

Heterogeneities at the meso-scale strongly influence the shock compression response of composite materials. Laminated geometries with full density and intimate particle contacts provide a unique system to investigate the influence of microstructure on a propagating shock wave. Computational analysis is used to understand the effects of layer orientation and bilayer spacing on the shock compression response of cold-rolled Ni/ Al multilayers. Real, heterogeneous microstructures, obtained from optical micrographs, are incorporated into the Eulerian, finite volume code CTH. The results show a marked difference in the dissipation and dispersion of the shock wave as the underlying microstructure varies.
Anisotropic Strain Effect on Electron Transport in C60Organic Field Effect transistors
Authors: Nigam Akash , Schwabegger Günther , Ullah Mujeeb , Ahmed Rizwan , Fishchuk Ivan I. , Kadashchuk Andrey , Simbrunner Clemens , Sitter Helmut , Premaratne Malin , Rao V.Ramgopal
Published: May 2013

Mechanical flexibility is one of the key advantages of organic semiconducting films in applications such as wearable-electronics or flexible displays. The present study is aimed at gaining deeper insight into the effect of strain on charge transport properties of the organic semiconductor films. We have fabricated high performance C60top gate organic field effect transistors (OFET) on flexible substrates and characterized the devices by curling the substrates in concave and convex manner, to apply varying values of compressive and tensile strain, respectively. Electron mobility is found to increase with compressive strain and decrease with tensile strain. The observed strain effect is found to be strongly anisotropic with respect to the direction of flow of current. This observation on mobility is quantified using an Extended Gaussian Disorder Model (EGDM) for the hopping charge transport. We suggest that the observed strain dependence of the electron transport is dominated by a change in the effective charge hopping distance over the grain boundaries in polycrystalline C60films.
Titanium and zirconium oxidation under argon irradiation in the low MeV range
Authors: Gorse-Pomonti Dominique , Do Ngoc-Long , Bérerd Nicolas , Moncoffre Nathalie , Baldinozzi Gianguido
Published: May 2013

We studied the irradiation effects on Ti and Zr surfaces in slightly oxidizing environment (rarefied dry air, 500°C) using multi-charged argon ions in the low MeV range (1 – 9 MeV) to the aim of determining the respective role of the electronic and nuclear stopping power in the operating oxidation process under irradiation. We have shown that ballistic collisions contribute significantly to the enhanced Ti and Zr oxidation under MeV argon bombardment. We have also shown that the projectile energy plays a significant role in the overall process.

A significant oxide film thickening is visible on titanium under irradiation, taking the form of a well-defined oxidation peak between 1 and 4 MeV, as a result of the Nuclear Backscattering Spectroscopy and Spectroscopic Ellipsometry studies.

A significant oxide film thickening is also visible on zirconium under same irradiation conditions, at 4 and 9 MeV, as a result of the NBS study. Work is in progress in order to determine how the modified oxidation process depends in this case on the projectile energy.
Scanning Angle Total Internal Reflection Raman Spectroscopy of Thin Polymer Films
Authors: Meyer Matthew W. , Smith Emily A.
Published: May 2013

Plasmon waveguide resonance (PWR) Raman spectroscopy provides chemical content information with interface or thin film selectivity. Near the plasmon waveguide interface, large increases in the interfacial optical energy density are generated at incident angles where plasmon waveguide resonances are excited. When a polymer of sufficient thickness is deposited on a gold film, the interface acts as a plasmon waveguide and large enhancements in the Raman signal can be achieved. This paper presents calculations to show how polymer thickness and excitation wavelength are predicted to influence PWR Raman spectroscopy measurements. The results show the optical energy density (OED) integrated over the entire polymer film using 785 nm excitation are 1.7× (400 nm film), 2.17× (500 nm film), 2.48× (600 nm film), 3.08× (700 nm film) and 3.62× (800 nm film) higher compared to a 300 nm film. Accounting for the integrated OED and frequency to the fourth power dependence of the Raman scatter, a 532 nm excitation wavelength is predicted to generate the largest PWR Raman signal at the polymer waveguide interface. This work develops a foundation for chemical measurements of numerous devices, such as solar energy capturing devices that utilize conducting metals coated with thin polymer films.
Study of dynamic features of highly energetic reactions by DSC and High-Speed Temperature Scanner (HSTS)
Authors: Hobosyan M.A. , Kirakosyan Kh.G. , Kharatyan S.L. , Martirosyan K.S.
Published: May 2013

The dynamic features of Al2O3 - polytetrafluoroethylene (PTFE) and Al - PTFE reactions in non-isothermal conditions are presented. The Differential Scanning Calorimetry (DSC) and High-Speed Temperature Scanner (HSTS) were used to characterize the Al2O3/Al – PTFE reactions at different heating rates. The study shows that the HSTS instrument can give more information about the reaction mechanism and kinetics than the conventional DSC measurements. In this work we show that high heating rates may reveal exothermic reaction between Al2O3 and PTFE that were previously unidentified. The PTFE can potentially remove the oxide layer from aluminum in the initial period of the reaction and increase the direct contact area between oxygen and aluminum, which increases the reaction velocity and improves the energy release abilities of the system.
Effect of dielectric/organic interface properties on the performance of the organic thin film transistors
Authors: Rahimi Ronak , Korakakis D.
Published: May 2013

In order to manufacture organic electronic devices with high performance, more detailed studies of the structure and the morphology of the organic materials as well as the underlying physical charge transport mechanisms are warranted. For instance, high efficiency organic thin film transistors (OTFTs) require materials with high charge carrier mobility [1, 2]. The parameters that determine the charge carrier mobility of the device include the structure of the first organic layer at the organic-dielectric interface as well as the morphology and the structural order of the other organic layers. Therefore, fundamental questions about structural properties of organic materials should be answered in order to optimize device performance [2-4].

In this work, several bilayer structures of LiF/PTCDI-C8 and LiF/pentacene were prepared and their morphology and molecular structure were characterized using X-ray reflectivity (XRR) technique. In order to study the effects of the films’ structures and dielectric/organic interfacial properties on the device performance, OTFTs based on these bilayers were fabricated and characterized. It has been observed that PTCDI-C8 thin films have higher molecular packing in the LiF/PTCDI-C8 bilayer structure, which results in superior electrical characteristics for OTFTs based on this organic material. Devices with LiF/PTCDI-C8 bilayer exhibit about one order of magnitude higher output current (Ids) at a constant drain-source voltage (Vds) compared to the devices with LiF/pentacene bilayer. The observed differences in the electrical characteristics of these devices can be attributed to the effects of the dielectric/organic interface and the molecular structure of the organic layers.
Multiscale Approach to Theoretical Simulations of Materials for Nuclear Energy Applications: Fe-Cr and Zr-based Alloys
Authors: Abrikosov Igor A. , Ponomareva Alena V. , Barannikova Svetlana A. , Hellman Olle , Vekilova Olga Yu. , Simak Sergei I. , Ruban Andrei V.
Published: May 2013

We review basic ideas behind state-of-the-art techniques for first-principles theoretical simulations of the phase stabilities and properties of alloys. We concentrate on methods that allow for an efficient treatment of compositional and thermal disorder effects. In particular, we present novel approach to evaluate free energy for strongly anharmonic systems. Theoretical tools are then employed in studies of two materials systems relevant for nuclear energy applications: Fe-Cr and Zr-based alloys. In particular, we investigate the effect of hydrostatic pressure and multicomponent alloying on the mixing enthalpy of Fe-Cr alloys, and show that in the ferromagnetic state both of them reduce the alloy stability at low Cr concentration. For Zr-Nb alloys, we demonstrate how microscopic parameters calculated from first-principles can be used in higher-level models.
Low Energy Atom Scattering Spectroscopy for Insulator Surface Analysis: MgO(111) Surfaces
Authors: Umezawa K.
Published: May 2013

This study described a low-energy atom scattering system combined with a time-of-flight spectrometer and an ultra high vacuum chamber for insulator surface structural analysis. We show one of examples to study of MgO(111) surface analysis. A visual image of Mg atoms due to the projected blocking pattern represents the crystalline structure of the MgO(111) surfaces. This figure shows the trajectory of scattered 4He0 particles due to Mg atoms along low-index lattice planes and crystallographic directions. Insulator surface structural analysis becomes more important in materials sciences.
Electrocatalytic effect towards NADH induced by HiPco single-walled carbon nanotubes covalently functionalized by ferrocene derivatives
Authors: Allali Naoual , Urbanova Veronika , Etienne Mathieu , Mallet Martine , Devaux Xavier , Vigolo Brigitte , Fort Yves , Walcarius Alain , Noël Maxime , McRae Edward , Soldatov Alexander V. , Dossot Manuel , Mamane Victor
Published: May 2013

The present work reports the covalent functionalization of single-walled carbon nanotubes (SWCNTs) by ferrocene derivatives with polyethyleneglycol linkers. A very clean initial sample was chosen to avoid any residual catalyst and carbon impurities. Functionalized SWCNTs (f-CNTs) are deposited on the surface of a glassy carbon electrode (GCE) and this modified electrode is used for oxidizing the cofactor NADH (dihydronicotinamide adenine dinucleotide) in the presence of diaphorase. A clear electrocatalytic effect is evidenced, which can only be attributed to the f-CNTs.
Periodontitis in Patients With Coronary Artery Disease: An 8‐Year Follow‐Up
Authors: Johansson Carin Starkhammar , Ravald Nils , Pagonis Christos , Richter Arina
Published: May 2013

Background: This study examines whether preceding assessment of periodontal status in patients with established coronary artery disease (CAD) can predict future CAD endpoints (myocardial infarction, new revascularization procedure, or CAD‐related death) during 8‐year follow‐up and whether the changes in periodontal status over time differ in patients with CAD compared with healthy controls.

Methods: In 2003, periodontal status was examined in 161 patients with CAD who underwent percutaneous coronary intervention or coronary artery bypass graft due to significant stenosis in the coronary arteries and 162 controls without CAD. Eight years later, 126 patients with CAD (102 males and 24 females, mean age: 68 ± 8.9 years) and 121 controls (101 males and 20 females, mean age: 69 ± 9.0 years) were reexamined periodontally. A standard classification of periodontal disease in three groups (mild, moderate, and severe) was used. CAD endpoints during follow‐up were obtained by review of medical records. CAD as cause of death was confirmed from the Swedish Cause of Death Register.

Results: No significant differences were found among patients with CAD, with or without CAD‐related endpoints at 8‐year follow‐up, and severity of periodontitis at baseline (P = 0.7). CAD did not influence the incidence or severity of periodontitis. Significant differences were found at the final examination in periodontitis prevalence and severity (P = 0.001), number of teeth (P = 0.006), probing depth 4 to 6 mm (P = 0.016), bleeding on probing (P = 0.001), and radiographic bone level (P = 0.042) between CAD patients and controls, all in favor of controls.

Conclusions: The study results did not show a significant association during 8 years among CAD endpoints and periodontal status at baseline. The progression of periodontitis was low in both groups, although the higher proportion of individuals with severe periodontitis among patients with CAD compared with controls remained unchanged over the 8‐year follow‐up. Further long‐term prospective studies are needed to show whether periodontitis can be considered a risk or prognostic factor for CAD, in terms of endpoints including myocardial infarction, new revascularization procedure, and CAD‐related death.
Serum Antibody Responses to Periodontal Microbiota in Chronic and Aggressive Periodontitis: A Postulate Revisited
Authors: Hwang Andrew M. , Stoupel Janet , Celenti Romanita , Demmer Ryan T. , Papapanou Panos N.
Published: May 2013

Background: The authors revisited the 1999 International Workshop postulate of robust serum antibody responses to infecting agents in localized aggressive periodontitis (LAgP) and weak responses in generalized aggressive periodontitis (GAgP). Antibody responses were further examined in localized and generalized chronic periodontitis (LCP and GCP).

Methods: The study includes 119 patients (60 males and 59 females, aged 11 to 76 years), 18 with LAgP, 37 with GAgP, 37 with LCP, and 27 with GCP. Multiple subgingival plaque samples/patient (1,057 in total) were analyzed with respect to 11 bacterial species using checkerboard DNA‐DNA hybridizations, and serum immunoglobulin (Ig)G levels were measured against the same bacteria using checkerboard immunoblotting. Further, infection ratios (antibody level over the average bacterial colonization by the homologous species) were computed for each patient. Comparisons of bacterial colonization, serum IgG levels, and infection ratios were made across the diagnostic categories using multivariable linear regression models adjusting for age and race/ethnicity.

Results: There were no statistically significant differences in serum IgG levels to Aggregatibacter actinomycetemcomitans among the four diagnostic categories. IgG levels to several species, including Porphyromonas gingivalis, Treponema denticola, and Campylobacter rectus, were highest in patients with GAgP and significantly different from LCP and GCP, but not from LAgP. Comparisons based on infection ratios showed no statistically significant differences for any species between GAgP and LAgP.

Conclusion: This study provides evidence against the 1999 Workshop's postulate of weak serum antibody responses in patients with GAgP and shows that serum IgG responses in GAgP are comparable to those in LAgP, but higher than in GCP or LCP for several species.
The Role of Geomechanical Observation in Continuous Updating of Thermal-Recovery Simulations With the Ensemble Kalman Filter
Authors: Azad A.. , Chalaturnyk R.J.. J.
Published: May 2013

In-situ thermal methods such as steam-assisted gravity drainage (SAGD) and cyclic steam stimulation (CSS) are widely used in oil-sand reservoirs. The physics of such thermal processes is generally well-understood, and it has been shown that rock properties are highly influenced by the geomechanical behavior of the reservoir during these recovery processes. Geomechanics improves the process dynamically, and its response can depict the progress of production within a reservoir. However, the potential of geomechanical monitoring is not usually practiced. With increased implementation of highly instrumented wells and communication technologies providing real-time monitoring data from different sources, combining available data into reservoir geomechanical simulations can improve updating numerical models and the prediction process. This research explores effective uses of geomechanical observation data for history matching and types of geomechanical observation sources adequate for thermal recovery. The ensemble Kalman filter (EnKF), combined with an iterative geomechanical coupled simulator, has been chosen as the data-assimilation algorithm to update the model continuously on the basis of geomechanical observations and production data. The results show that considering geomechanical modeling and observation improves history matching when geomechanical behavior plays a role in the process.
Post-Well Shale-Stability Modeling and History Matching in Norwegian North Sea
Authors: Nes Olav-Magnar , Bøe Reidar , Sønstebø Eyvind F. , Gran Kjetil , Wold Sturla , Saasen Arild , Fjogstad Arild
Published: May 2013

Severe borehole-stability problems were encountered in a recent exploration well in the Norwegian North Sea. The problems occurred when drilling through Tertiary shale sections interbedded with permeable sand layers. Drilling was initially performed with water-based mud (WBM). However, because the section target was not able to be reached after more than 2 weeks of operation, the section was plugged back, and a sidetrack was drilled with an oil-based mud (OBM) without encountering major operational problems.

On the basis of the post-drill analysis of drilling data, well logs, drill cuttings, and borehole cavings sampled from the well, this paper describes how the complex combination of drilling-fluid salt concentration and geological constraints may be used to ensure successful future drilling operations in this part of the North Sea.

Cuttings and preserved cavings collected during the drilling operation were selected from several depth intervals identified as potentially troublesome from drilling experience and log data. The determination of cuttings mineralogy enabled a better prediction of how the time dependency of the stable drilling-fluid-density window is influenced by an interaction between the shale and the drilling fluid. Mechanical strength is a key input parameter when predicting borehole stability. Dedicated rock-mechanical punch measurements on cavings were used to confirm the prediction of strength from log data alone. The examination of caving surfaces revealed the possible presence of in-situ-fractured rock. Such fractures would require special measures while drilling to maintain stability.

Subsequently, a borehole-stability sensitivity analysis was performed that focused on time-dependent stability in the shale formations. The analysis used cuttings and cavings properties and logs as input. In particular, the modeling showed how the optimal potassium chloride (KCl) concentration in the drilling fluid changes with depth. The modeling further identified a relatively large sensitivity toward borehole inclination—even at fairly small inclinations. This paper thus illustrates the significance of properly accounting for rock-mechanical aspects when planning new wells.