bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Shear Degradation of Lost-Circulation Materials
Authors: Valsecchi Pietro 
Published: August 2014

Summary
Lost-circulation materials (LCMs) are widely used to mitigate fluid loss when drilling permeable zones. Their effectiveness, however, generally declines with circulation time, and this decline is linked to the reduction in the average size of the solids components, or “shear degradation.” In this paper, dimensional analysis and first-principle physics are used to frame those mechanisms into a scientific definition that directly connects the progressive LCM size reduction to operational parameters such as the densities of particles and suspending fluid, the size of particles, and the fluid viscosity.
The introduction of large-sized materials in the drilling-mud circulation system has become a common practice during the past few decades for the mitigation of lost circulation while drilling in permeable intervals. Solids with an average diameter larger than 100 μm are carried with the drilling mud and, when fractures occur, they deposit in the fractures or at the opening of the fractures, successfully blocking the discharge of fluid out of the wellbore. The effectiveness of such material was observed, however, to decline over time as the drilling mud circulates through the mud pumps, the drillstring, the bit nozzles, the wellbore annulus, and the mud-recycling system. The decline over time in the effectiveness of the so-called LCMs and loss-prevention materials (LPMs) during drilling is widely linked to the degradation of the LCM/LPM components that have an average size that drops with circulation time.
A large amount of literature in the petroleum industry is dedicated to the investigation of the issue, and numerous experimental studies have attempted to quantify the LCM degradation by reproducing the root phenomena in the laboratory. The concept of “shear degradation” has thus become a synonym for such studies, and it is widely used for the selection of materials to be used in drilling operations.
In the present paper, a harder look is taken on the very concept of “shear degradation” and on its effectiveness in capturing the progressive size reduction of LCM during circulation. By use of dimensional analysis, the tendency of a material to degrade can be determined in advance, whereby the density of the particles and suspending fluid, the size of particles, and the fluid viscosity are examined as the governing parameters. Understanding the underlying physics enables the selection of a more-shear-resistant engineered-particle drilling fluid, regardless of its application.
Transdentinal Cytotoxicity of Carbodiimide (EDC) and Glutaraldehyde on Odontoblast-like Cells
Authors: Scheffel DLS , Bianchi L , Soares DG , Basso FG , Sabatini C , de Souza Costa CA , Pashley DH , Hebling J 
Published: August 2014

SUMMARYObjectiveTo evaluate the transdentinal cytotoxicity of three different concentrations of carbodiimide (EDC) or 5% glutaraldehyde (GA) on MDPC-23 cells.MethodsSeventy 0.4-mm-thick dentin disks obtained from human molars were adapted to artificial pulp chambers. MDPC-23 cells were seeded on the pulpal surface of the disks. After 48 hours, the occlusal dentin was acid-etched and treated for 60 seconds with one of the following solutions (n=10): no treatment (negative control); 0.1 M, 0.3 M, or 0.5 M EDC; 5% GA; Sorensen buffer; or 29% hydrogen peroxide (positive control). Cell viability and morphology were assessed by methyltetrazolium assay and scanning electron microscopy (SEM), respectively. The eluates were collected after the treatments and applied on MDPC-23 seeded in a 24-well plate to analyze cell death, total protein (TP), and collagen production. The last two tests were performed 24 hours and seven days after the challenge. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (p&lt;0.05).ResultsEDC at all test concentrations did not reduce cell viability, while 5% GA did increase cell metabolism. Cell death by necrosis was not elicited by EDC or 5% GA. At the 24-hour period, 0.3 M and 0.5 M EDC reduced TP production by 18% and 36.8%, respectively. At seven days, increased TP production was observed in all groups. Collagen production at the 24-hour period was reduced when 0.5 M EDC was used. After seven days, no difference was observed among the groups. SEM showed no alteration in cell morphology or number, except in the hydrogen peroxide group.ConclusionsTreatment of acid-etched dentin with EDC or GA did not cause transdentinal cytotoxic effects on odontoblast-like cells.
Diagnosis and management of primary pyogenic spinal infections in intravenous recreational drug users
Authors: Ziu Mateo , Dengler Bradley , Cordell Davin , Bartanusz Viktor 
Published: August 2014

Object
Primary spine infection secondary to intravenous drug abuse (IVDA) is a difficult clinical entity encountered by spine surgeons and infectious disease specialists. Patients tend to be noncompliant with the treatment and follow-up, and some continue to use IV recreational drugs even after the diagnosis of spine infection. The authors undertook this study to analyze the presentation, etiology, demographic characteristics, treatment, and outcome of primary pyogenic spinal infection in patients with IVDA as the major risk factor.

Methods
The medical records, radiology imaging, and laboratory results (white blood cell count, inflammatory markers, bacteriology cultures) of all patients with pyogenic spine infection and history of IVDA presenting to a tertiary care center from August 2005 through December 2013 were retrospectively reviewed. The department of neurosurgery database and the hospital electronic medical records of University Hospital in San Antonio were used to identify the cohort for our study.

Results
A total of 164 patients with spinal infection were evaluated during the study period; 102 of these patients had a history of IVDA. Their average age was 45.4 years, and only 14 (13.7%) were women. The mean laboratory values at presentation included a white blood cell count of 11.1 × 103 cells/μl (range 0.5–32 × 103 cells/μl), erythrocyte sedimentation rate (ESR) of 74 mm/hr (range 9.9–140 mm/hr), and C-reactive protein (CRP) level of 67 mg/L (range 0.1–327 mg/L). Twenty-six patients (25.4%) had an associated epidural abscess. The most common organism isolated from cultures of the bone and/or blood was methicillin-sensitive Staphylococcus aureus (MSSA), which was found in 37 cases. A close second was methicillin-resistant S. aureus (MRSA), found in 23 cases. The most commonly involved region was the lumbar spine (24 cases [57.8%]), and most patients (69.6%) had involvement of only a single level. Eighty patients were initially treated with long-term IV antibiotic therapy, and only 22 underwent surgical intervention (24 procedures). Of the latter group, 8 patients underwent laminectomy alone while 16 required some type of instrumented stabilization. Of the patients requiring stabilization procedures, 2 (12.5%) required reoperation with extension of their surgical constructs to other levels. The average follow-up was 29.7 weeks (range 6 weeks to 3 years).

Conclusions
Diagnosis and management of spinal infection in patients with a history of IVDA is challenging. The data from this study show that initial laboratory values are difficult to interpret given that only a minority of these patients present with leukocytosis. Back pain was the only reliable predictor of spine infection. The authors' experience indicates that the majority of patients with spine infection and a history of IVDA can be successfully treated with IV antibiotic therapy alone.
Waldunternehmen gehört die Zukunft (Essay)
Authors: Schmidt Roger , Hostettler Martin 
Published: August 2014

The future belongs to forest entrepreneurs (essay)
An evaluation has recently been carried out of the achievements and organization of the Forest Service of the Canton of Bern. It appears from the study that the present administrative structure is not adequately adapted to the challenges of the future: a lower level of forest management, increasing expectations for the forest, higher risk, fewer management options for forest development. The new strategy for the Service is “Help the forest owners to help themselves”. Forest entrepreneurs are the motor of the forest economy. The Canton of Bern, working with the forest owner association of the Canton, is therefore looking for new ways of working with them. It is focusing on its core tasks and giving organizational priority to solidarity, speed of response and concentration of resources.
A Survey of Children’s Reported Experience in Outpatient Pediatric Ophthalmology Clinics
Authors: Tan Naomi E. T. , Lim Wei Sing , Jain Saurabh 
Published: August 2014

Purpose:
Patient-reported experience measures influence contemporary health care. To monitor the experience of children in health care, some inherent difficulties must be overcome. The authors sampled the opinion of children in outpatient pediatric ophthalmology clinics.

Methods:
Questionnaires were designed and distributed to children ages 2 to 16 years in pediatric ophthalmology clinics over three sites.

Results:
Ninety-three forms were completed by children ages 2 to 16 years. The average duration of clinic visits was 69 minutes. Children commented that helpful staff improved their experience. Waiting times and boredom were negative issues raised consistently. Children particularly enjoyed visual acuity testing, which they also described as the most challenging aspect of the clinic. On average, patients found eye drops only mildly painful.

Conclusions:
Various areas for service improvement were identified from this study, including the value of keeping children occupied and minimizing waiting times. It was not clear to children which healthcare professionals they were seeing and this was an area of confusion. Adolescent patients felt the clinic was too childish. Sampling children’s opinions through questionnaires had some limitations in terms of some inconsistencies of response, incomplete questionnaires, and multiple answers, but overall provided useful information specific to the clinics.

[J Pediatr Ophthalmol Strabismus 2014;51(5):270–273.]
BECCS capability of dedicated bioenergy crops under a future land‐use scenario targeting net negative carbon emissions
Authors: Kato Etsushi , Yamagata Yoshiki 
Published: July 2014

AbstractBioenergy with Carbon Capture and Storage (BECCS) is a key component of mitigation strategies in future socioeconomic scenarios that aim to keep mean global temperature rise below 2°C above preindustrial, which would require net negative carbon emissions in the end of the 21st century. Because of the additional need for land, developing sustainable low‐carbon scenarios requires careful consideration of the land‐use implications of deploying large scale BECCS. We evaluated the feasibility of the large‐scale BECCS in RCP2.6, which is a scenario with net negative emissions aiming to keep the 2°C temperature target, with a top‐down analysis of required yields and a bottom‐up evaluation of BECCS potential using a process‐based global crop model. Land‐use change carbon emissions related to the land expansion were examined using a global terrestrial biogeochemical cycle model. Our analysis reveals that first‐generation bioenergy crops would not meet the required BECCS of the RCP2.6 scenario even with a high‐fertilizer and irrigation application. Using second‐generation bioenergy crops can marginally fulfill the required BECCS only if a technology of full postprocess combustion CO2 capture is deployed with a high‐fertilizer application in the crop production. If such an assumed technological improvement does not occur in the future, more than doubling the area for bioenergy production for BECCS around 2050 assumed in RCP2.6 would be required; however, such scenarios implicitly induce large‐scale land‐use changes that would cancel half of the assumed CO2 sequestration by BECCS. Otherwise, a conflict of land use with food production is inevitable.
Do seasonal‐to‐decadal climate predictions underestimate the predictability of the real world?
Authors: Eade Rosie , Smith Doug , Scaife Adam , Wallace Emily , Dunstone Nick , Hermanson Leon , Robinson Niall 
Published: July 2014

AbstractSeasonal‐to‐decadal predictions are inevitably uncertain, depending on the size of the predictable signal relative to unpredictable chaos. Uncertainties can be accounted for using ensemble techniques, permitting quantitative probabilistic forecasts. In a perfect system, each ensemble member would represent a potential realization of the true evolution of the climate system, and the predictable components in models and reality would be equal. However, we show that the predictable component is sometimes lower in models than observations, especially for seasonal forecasts of the North Atlantic Oscillation and multiyear forecasts of North Atlantic temperature and pressure. In these cases the forecasts are underconfident, with each ensemble member containing too much noise. Consequently, most deterministic and probabilistic measures underestimate potential skill and idealized model experiments underestimate predictability. However, skilful and reliable predictions may be achieved using a large ensemble to reduce noise and adjusting the forecast variance through a postprocessing technique proposed here.
Seasonal variation and solar activity dependence of the quiet‐time ionospheric trough
Authors: Ishida T. , Ogawa Y. , Kadokura A. , Hiraki Y. , Häggström I. 
Published: July 2014

AbstractWe have conducted a statistical analysis of the ionospheric F region trough, focusing on its seasonal variation and solar activity dependence under geomagnetically quiet and moderate conditions, using plasma parameter data obtained via Common Program 3 observations performed by the European Incoherent Scatter (EISCAT) radar between 1982 and 2011. We have confirmed that there is a major difference in frictional heating between the high‐ and low‐latitude sides of the EISCAT field of view (FOV) at ~73°0′N–60°5′N (geomagnetic latitude) at an altitude of 325 km, which is associated with trough formation. Our statistical results show that the high‐latitude and midlatitude troughs occur on the high‐ and low‐latitude sides of the FOV, respectively. Seasonal variations indicate that dissociative recombination accompanied by frictional heating is a main cause of trough formation in sunlit regions. During summer, therefore, the occurrence rate is maintained at 80–90% in the postmidnight high‐latitude region owing to frictional heating by eastward return flow. Solar activity dependence on trough formation indicates that field‐aligned currents modulate the occurrence rate of the trough during the winter and equinox seasons. In addition, the trough becomes deeper via dissociative recombination caused by an increased ion temperature with F10.7, at least in the equinox and summer seasons but not in winter.
Paleomobility in the Tiwanaku Diaspora: Biogeochemical analyses at Rio Muerto, Moquegua, Peru
Authors: Knudson Kelly J. , Goldstein Paul S. , Dahlstedt Allisen , Somerville Andrew , Schoeninger Margaret J. 
Published: July 2014

AbstractPaleomobility has been a key element in the study of the expansion of ancient states and empires, including the Tiwanaku polity of the South Central Andes (AD 500–1000). We present radiogenic strontium and oxygen isotope data from human burials from three cemeteries in the Tiwanaku‐affiliated Middle Horizon archaeological site complex of Rio Muerto in the Moquegua Valley of southern Peru. At Rio Muerto, archaeological human enamel and bone values range from 87Sr/86Sr = 0.70657–0.72018, with a mean of 87Sr/86Sr = 0.70804 ± 0.00207 (1σ, n = 55). For the subset of samples analyzed for oxygen isotope values (n = 48), the data ranges from δ18Ocarbonate(VSMOW) = +18.1 to +27.0‰. When contextualized with other lines of archaeological evidence, we interpret these data as evidence for an archaeological population in which the majority of individuals had “local” origins, and were likely second‐generation, or more, immigrants from the Tiwanaku heartland in the altiplano. Based on detailed life history data, we argue a smaller number of individuals came at different ages from various regions within the Tiwanaku polity. We consider whether these individuals with isotopic values consistent with “nonlocal” geographic origins could represent first‐generation migrants, marriage exchange partners, or occupationally mobile herders, traders or other travelers. By combining isotopic life history studies with mortuary treatment data, we use a person‐centered migration history approach to state integration and expansion. Isotopic analyses of paleomobility at the Rio Muerto site complex contribute to the role of diversity in ancient states by demonstrating the range of geographic origins rather than simply colonists from the Lake Titicaca Basin. Am J Phys Anthropol 155:405–421, 2014. © 2014 Wiley Periodicals, Inc.
Photocatalytic Water Oxidation by a Mixed‐Valent MnIII3MnIVO3 Manganese Oxo Core that Mimics the Natural Oxygen‐Evolving Center
Authors: Al‐Oweini Rami , Sartorel Andrea , Bassil Bassem S. , Natali Mirco , Berardi Serena , Scandola Franco , Kortz Ulrich , Bonchio Marcella 
Published: July 2014

AbstractThe functional core of oxygenic photosynthesis is in charge of catalytic water oxidation by a multi‐redox MnIII/MnIV manifold that evolves through five electronic states (Si , where i=0–4). The synthetic model system of this catalytic cycle and of its S0→S4 intermediates is the expected turning point for artificial photosynthesis. The tetramanganese‐substituted tungstosilicate [MnIII3MnIVO3(CH3COO)3(A‐α‐SiW9O34)]6− (Mn4POM) offers an unprecedented mimicry of the natural system in its reduced S0 state; it features a hybrid organic–inorganic coordination sphere and is anchored on a polyoxotungstate. Evidence for its photosynthetic properties when combined with [Ru(bpy)3]2+ and S2O82− is obtained by nanosecond laser flash photolysis; its S0→S1 transition within milliseconds and multiple‐hole‐accumulating properties were studied. Photocatalytic oxygen evolution is achieved in a buffered medium (pH 5) with a quantum efficiency of 1.7 %.
Palladium‐Catalyzed Cascade CH Trifluoroethylation of Aryl Iodides and Heck Reaction: Efficient Synthesis of ortho‐Trifluoroethylstyrenes
Authors: Zhang Hao , Chen Pinhong , Liu Guosheng 
Published: July 2014

AbstractA palladium‐catalyzed selective CH bond trifluoroethylation of aryl iodides has been explored. The reaction allows for the efficient synthesis of a variety of ortho‐trifluoroethyl‐substituted styrenes. Preliminary mechanistic studies indicate that the reaction might involve a key PdIV intermediate, which is generated through the rate‐determining oxidative addition of CF3CH2I to a palladacycle; the bulky nature of CF3CH2I influences the reactivity. Reductive elimination from the PdIV complex then leads to the formation of the aryl–CH2CF3 bond.
Stereoselective Construction of 1,3‐Disilylcyclopentane Derivatives by Scandium‐Catalyzed [3+2] Cycloaddition of Allylsilanes to β‐Silylenones
Authors: Okamoto Kazuhiro , Tamura Eisuke , Ohe Kouichi 
Published: July 2014

AbstractThe Sc(OTf)3‐catalyzed [3+2] cycloaddition of allylsilanes to β‐silyl‐α,β‐unsaturated ketones (β‐silylenones) has been developed to form five‐membered syn‐1,3‐disilylketones diastereoselectively through the rearrangement of the silicon substituents on the allylsilane. Stabilization of the carbocation intermediates by a double silicon effect plays a key role in directing the course of the reaction to favor the [3+2] cycloaddition pathway over simple allylation.
Palladium‐Catalyzed Synthesis of Ammonium Sulfinates from Aryl Halides and a Sulfur Dioxide Surrogate: A Gas‐ and Reductant‐Free Process
Authors: Emmett Edward J. , Hayter Barry R. , Willis Michael C. 
Published: July 2014

AbstractSulfonyl‐derived functional groups populate a broad range of useful molecules and materials, and despite a variety of preparative methods being available, processes which introduce the most basic sulfonyl building block, sulfur dioxide, using catalytic methods, are rare. Described herein is a simple reaction system consisting of the sulfur dioxide surrogate DABSO, triethylamine, and a palladium(0) catalyst for effective convertion of a broad range of aryl and heteroaryl halides into the corresponding ammonium sulfinates. Key features of this gas‐ and reductant‐free reaction include the low loadings of palladium (1 mol %) and ligand (1.5 mol %) which can be employed, and the use of isopropyl alcohol as both a solvent and formal reductant. The ammonium sulfinate products are converted in situ into a variety of sulfonyl‐containing functional groups, including sulfones, sulfonyl chlorides, and sulfonamides.
Mapping Polyamide–DNA Interactions in Human Cells Reveals a New Design Strategy for Effective Targeting of Genomic Sites
Authors: Erwin Graham S. , Bhimsaria Devesh , Eguchi Asuka , Ansari Aseem Z. 
Published: July 2014

AbstractTargeting the genome with sequence‐specific synthetic molecules is a major goal at the interface of chemistry, biology, and personalized medicine. Pyrrole/imidazole‐based polyamides can be rationally designed to target specific DNA sequences with exquisite precision in vitro; yet, the biological outcomes are often difficult to interpret using current models of binding energetics. To directly identify the binding sites of polyamides across the genome, we designed, synthesized, and tested polyamide derivatives that enabled covalent crosslinking and localization of polyamide–DNA interaction sites in live human cells. Bioinformatic analysis of the data reveals that clustered binding sites, spanning a broad range of affinities, best predict occupancy in cells. In contrast to the prevailing paradigm of targeting single high‐affinity sites, our results point to a new design principle to deploy polyamides and perhaps other synthetic molecules to effectively target desired genomic sites in vivo.
Persistent Antimony‐ and Bismuth‐Centered Radicals in Solution
Authors: Ishida Shintaro , Hirakawa Fumiya , Furukawa Ko , Yoza Kenji , Iwamoto Takeaki 
Published: July 2014

AbstractStibinyl and bismuthinyl radicals are recognized as representative intermediates of antimony and bismuth compounds, but still elusive in the condensed phase. We successfully synthesized persistent stibinyl and bismuthinyl radicals in solution by facile dissociation of the corresponding dimers with bulky substituents. We characterized the radicals by NMR and UV/Vis spectroscopy and estimated the thermodynamic parameters for the dissociation equilibria. The radicals show n→p (HOMO→SOMO) transition bands at 497 nm (stibinyl) and 543 nm (bismuthinyl) in 3‐methylpentane and react with a stable nitroxyl radical to give the cross‐radical coupling products in good yields.
The Dominant Role of Chalcogen Bonding in the Crystal Packing of 2D/3D Aromatics
Authors: Fanfrlík Jindřich , Přáda Adam , Padělková Zdeňka , Pecina Adam , Macháček Jan , Lepšík Martin , Holub Josef , Růžička Aleš , Hnyk Drahomír , Hobza Pavel 
Published: July 2014

AbstractThe chalcogen bond is a nonclassical σ‐hole‐based noncovalent interaction with emerging applications in medicinal chemistry and material science. It is found in organic compounds, including 2D aromatics, but has so far never been observed in 3D aromatic inorganic boron hydrides. Thiaboranes, harboring a sulfur heteroatom in the icosahedral cage, are candidates for the formation of chalcogen bonds. The phenyl‐substituted thiaborane, synthesized and crystalized in this study, forms sulfur⋅⋅⋅π type chalcogen bonds. Quantum chemical analysis revealed that these interactions are considerably stronger than both in their organic counterparts and in the known halogen bond. The reason is the existence of a highly positive σ‐hole on the positively charged sulfur atom. This discovery expands the possibilities of applying substituted boron clusters in crystal engineering and drug design.