bluuebunny/crossref_metadata_2025_split huggingface dataset:
NWS Tornado Warnings with Zero or Negative Lead Times
Authors: Brotzge J. , Erickson S. 
Published: August 2008

Abstract
During a 5-yr period of study from 2000 to 2004, slightly more than 10% of all National Weather Service (NWS) tornado warnings were issued either simultaneously as the tornado formed (i.e., with zero lead time) or minutes after initial tornado formation but prior to tornado dissipation (i.e., with “negative” lead time). This study examines why these tornadoes were not warned in advance, and what climate, storm morphology, and sociological factors may have played a role in delaying the issuance of the warning. This dataset of zero and negative lead time warnings are sorted by their F-scale ratings, geographically by region and weather forecast office (WFO), hour of the day, month of the year, tornado-to-radar distance, county population density, and number of tornadoes by day, hour, and order of occurrence. Two key results from this study are (i) providing advance warning on the first tornado of the day remains a difficult challenge and (ii) the more isolated the tornado event, the less likelihood that an advance warning is provided. WFOs that experience many large-scale outbreaks have a lower proportion of warnings with negative lead time than WFOs that experience many more isolated, one-tornado or two-tornado warning days. Monthly and geographic trends in lead time are directly impacted by the number of multiple tornado events. Except for a few isolated cases, the impacts of tornado-to-radar distance, county population density, and storm morphology did not have a significant impact on negative lead-time warnings.
Endovascular therapy for critical limb ischemia
Authors: Arain Salman A , White Christopher J 
Published: August 2008

Abstract Chronic critical limb ischemia (CLI) occurs when arterial perfusion is reduced below a threshold level that results in rest pain and/or tissue breakdown in the lower extremities. Importantly, it is associated with high cardiovascular morbidity and mortality. Without prompt revascularization, CLI may result in loss of a limb (i.e. amputation) and/or life. The goal of endovascular therapy is the re-establishment of pulsatile, straight-line flow to the distal extremity. Percutaneous transluminal angioplasty (PTA) has been shown to be effective and safe in the setting of CLI, with limb salvage rates that compare favorably with surgical procedures. Stents are indicated for failed PTA, while adjunctive therapies such as lasers, thermal angioplasty and atherectomy devices lack data demonstrating improved efficacy compared with conventional lower extremity interventions. In addition to successful revascularization, the institution of lifestyle changes, atherosclerotic risk factor modification, and pharmacologic therapies are indicated to reduce cardiovascular morbidity and mortality.
Measurement characteristics of the ankle–brachial index: results from the Action for Health in Diabetes study
Authors: Espeland Mark A , Regensteiner Judith G , Jaramillo Sarah A , Gregg Edward , Knowler William C , Wagenknecht Lynne E , Bahnson Judy , Haffner Steven , Hill James , Hiatt William R 
Published: August 2008

Abstract Many protocols have been used in clinical and research settings for collecting systolic blood pressure (SBP) measurements to calculate the ankle–brachial index (ABI); however, it is not known how useful it is to replicate measurements and which measures best reflect cardiovascular risk. Standardized measurements of ankle and arm SBP from 5140 overweight or obese individuals with type 2 diabetes were used to estimate sources of variation. Measurement characteristics of leg-specific ABI, as calculated using a standard algorithm based on the highest SBP of the dorsalis pedis or posterior tibial arteries, were projected using simulations. Coefficients of variability ranged from 2% to 3% when single SBP measurements were used and ABI was overestimated by 2–3%. Taking two SBP measurements at each site reduced standard errors and bias each by 30–40%. The sensitivity of detecting low ABI ranges exceeded 90% for ABI within 0.05 of the 0.90 clinical cut-point. The average and the minimum of the two (i.e. right and left) leg-specific ABI values had similar U-shaped relationships with Framingham risk scores; however, the average leg ABI had slightly greater precision. Replicating SBP measurements reduces the error and bias of ABI. Averaging leg-specific values may increase power for characterizing cardiovascular disease risk.
Critical limb ischemia: medical and surgical management
Authors: Slovut David Paul , Sullivan Timothy M 
Published: August 2008

Abstract Chronic critical limb ischemia (CLI), defined as > 2 weeks of rest pain, ulcers, or tissue loss attributed to arterial occlusive disease, is associated with great loss of both limb and life. Therapeutic goals in treating patients with CLI include reducing cardiovascular risk factors, relieving ischemic pain, healing ulcers, preventing major amputation, improving quality of life and increasing survival. These aims may be achieved through medical therapy, revascularization, or amputation. Medical therapy includes administration of analgesics, local wound care and pressure relief, treatment of infection, and aggressive therapy to modify atherosclerotic risk factors. For patients who are not candidates for revascularization, and who are unwilling or unable to undergo amputation, treatments such as intermittent pneumatic compression or spinal cord stimulation may offer symptom relief and promote wound healing. Revascularization offers the best option for limb salvage. The decision to perform surgery, endovascular therapy, or a combination of the two modalities (‘hybrid’ therapy) must be individualized. Patients who are relatively fit and able to withstand the rigors of an open procedure may benefit from the long-term durability of surgical repair. In contrast, frail patients with a limited life expectancy may experience better outcomes with endovascular reconstruction. Hybrid therapy is an attractive option for patients with limited autologous conduit, as it permits complete revascularization with a less extensive procedure, shorter duration of operation, and decreased risk of peri-operative complications. Amputation should be considered for patients who are non-ambulatory, demented, or unfit to undergo revascularization.
The prevalence of occult peripheral arterial disease among patients referred for orthopedic evaluation of leg pain
Authors: Bernstein Joseph , Esterhai John L , Staska Mitchell , Reinhardt Sally , Mitchell Marc E 
Published: August 2008

Abstract Lower extremity peripheral arterial disease (PAD) and musculoskeletal conditions both produce symptoms of leg pain, and may coexist. This study assesses the prevalence of PAD among patients referred to orthopedic surgery for evaluation of lower extremity pain. Fifty consecutive patients aged 50 years or more who had a chief complaint of leg pain, no history of trauma, and no previous history of PAD were studied prospectively. The presence of known risk factors for PAD and classic claudication symptoms was assessed by telephone interview and medical record review. Individuals were then evaluated by measurement of the ankle–brachial index (ABI) using Doppler and pulse volume recordings (PVR). A patient was deemed to have PAD if the ABI was below 0.9 or if the PVR demonstrated significant abnormalities. Occult PAD was detected in 10 of the 50 patients (20%) on the basis of the non-invasive vascular studies. There were no differences between patients with PAD and those without PAD regarding the presence of risk factors for PAD. None of the patients without PAD had claudication, while only one of the 10 patients with PAD had symptoms of classic claudication. In conclusion, 20% of patients referred by primary care providers to the orthopedic surgery clinic for lower extremity pain were discovered to have occult PAD. The majority of these patients did not have claudication. Orthopedic surgeons and primary care providers must maintain an appropriately high index of suspicion for PAD when evaluating patients with non-traumatic lower extremity pain.
Patient with both Wilkie syndrome and nutcracker syndrome
Authors: Barsoum Michel K , Shepherd Roger FJ , Welch Timothy J 
Published: August 2008

Abstract Wilkie syndrome or superior mesenteric artery syndrome is a rare cause of duodenal obstruction in pediatric and adult age groups. Its manifestations are due to compression of the third portion of the duodenum between the aorta and the superior mesenteric artery. We present one case of a 29-year-old female with a recent history of epigastric pain and severe weight loss due to duodenal obstruction from superior mesenteric syndrome. She was treated conservatively with jejunostomy tube feeding to regain loss of weight. Our case is unique in that the patient has also nutcracker syndrome.
Subscapularis Muscle Mechanics in Children with Obstetric Brachial Plexus Palsy
Authors: EINARSSON F. , HULTGREN T. , LJUNG B. -O. , RUNESSON E. , FRIDÉN J. 
Published: August 2008

This study investigates the passive mechanical properties of the subscapularis muscle in children with a contracture as a result of obstetrical brachial plexus palsy. Muscle biopsies were harvested from nine children undergoing open surgery for shoulder contracture. Passive mechanical testing of single cells and muscle bundles was performed. Corresponding comparisons were made using muscle biopsies from seven healthy controls. Single muscle fibres from patients with obstetric brachial plexus palsy displayed a shorter slack sarcomere length, linear deformation of the fibre within a wider zone of sarcomere length and a greater relative increase in stiffness compared with muscle bundles. We conclude that secondary changes in muscle fibre properties will occur as a result of a longstanding lack of sufficient passive stretch, leading to compensatory changes in the extracellular matrix. These results suggest the presence of a dynamic feedback system constituting a muscle-to-extracellular matrix communication interface.
Clinical Results of Flexor Tendon Repair in Zone II Using a Six-Strand Double-Loop Technique Compared with a Two-Strand Technique
Authors: Hoffmann G. L. , Büchler U. , Vögelin E. 
Published: August 2008

The clinical and functional results of 46 patients who underwent zone II flexor tendon repair using the Lim/Tsai technique combined with the Kleinert/Duran early active mobilisation regime and place and hold exercises were assessed. The results were compared with 25 patients who were treated by the modified Kessler technique and the Kleinert/Duran regime alone. After a follow-up of 8 to 17 weeks, the Lim/Tsai group had a better grip strength and a significantly better total active motion of 141° compared with 123°. The rupture rates (Lim/Tsai: 1/51; Kessler: 3/26) and the extension deficits were not statistically different in the two groups. However, the complication rate was significantly lower and the average time of treatment was significantly shorter in the Lim/Tsai group. These results support the use of the Lim/Tsai six-strand repair technique in zone II flexor tendon injuries and early active mobilisation without rubber-band traction.
Ectomycorrhizal weathering, a matter of scale?
Authors: Smits M. M. , Bonneville S. , Haward S. , Leake J. R. 
Published: August 2008

AbstractBoreal forest trees influence mineral weathering rates via exudation and uptake processes. Most trees in the boreal forest live in symbiosis with ectomycorrhizal (EcM) fungi that sheath most of the root tips and form the main interface between the tree and the soil. Current weathering models do not take into account the nature and scale of fungal-mineral interactions. Here we show for the first time grain-scale effects of EcM fungi in symbiosis with a host plant on mineral weathering under sterile conditions. EcM fungi actively direct their growth and energy flow towards mineral grains containing essential nutrient elements for the tree and fungus.
Macro- to nanoscale study of the effect of aqueous sulphate on calcite growth
Authors: Vavouraki A. I. , Putnis C. V. , Putnis A. , Oelkers E. H. , Koutsoukos P. G. 
Published: August 2008

AbstractCalcite growth rates were measured in the presence of sulphate using mixed-flow reactors and in situ Atomic Force Microscopy. Preliminary observations reveal that the kinetics and mechanism of the calcite growth was altered by the presence of sulphate. Calcite growth rates in the presence of sulphate (≥ mM) were decreased and two-dimensional nuclei tend to grow on top of existing nuclei, rather than spreading. The height of new nuclei was ~4 Å, 1 Å greater than that of pure calcite growth. This difference reflects the incorporation of tetrahedral SO2-4 anions into the calcite lattice.
Etch pits on naturally altered olivine from dunites of the Appalachian Blue Ridge Mountains, North Carolina, USA
Authors: Velbel M. A. , Ranck J. M. 
Published: August 2008

AbstractNaturally weathered olivine from metamorphosed, tectonized metadunite is corroded by funnel-shaped etch pits. Large etch pits form by weathering, and are not inherited from pre-weathering alteration of these rocks. Comparison of etch pits on olivine in naturally weathered metadunite with naturally weathered olivine phenocrysts from volcanic rocks suggests that olivine etch pits are similar in all sample suites, despite differences in crystallization and weathering/exposure ages, and regolith history.
Formation of hydroxysulphate and hydroxycarbonate green rusts in the presence of zinc using time-resolved in situ small and wide angle X-ray scattering
Authors: Ahmed I. A. M. , Shaw S. , Benning L. G. 
Published: August 2008

AbstractThe formation and transformation of hydroxysulphate (GRSO4) and hydroxycarbonate (GRCO3) Green Rusts were studied in situ using synchrotron-based time-resolved small and wide angle X-ray scattering. The time-resolved data revealed, for the first time, the pH dependent transition from poorly-ordered schwertmannite (pH <6.5) into GRSO4 (pH ~6.8) followed by GRCO3 (at pH ~9.6). These data also showed that the addition of Zn to the starting sulphate Fe2+/Fe3+ solution resulted in a change in size of the GR unit-cell due to substitution of Zn into the GR structure.
The blue colouring of beryls from Licungo, Mozambique: an X-ray absorption spectroscopy study at the iron K-edge
Authors: Figueiredo M. O. , Pereira da Silva T. , Veiga J. P. , Leal Gomes C. , De Andrade V. 
Published: August 2008

AbstractThe colours of natural and synthetic beryl (ideally Be3Al2Si6O18) have been attributed either tothe presence of chromophore ions partially replacing Al and/or Be (Cr3+, Fe2+/3+, Mn2+) or to the occurrence of colour centres related to the presence of multi-atomic groups. However, no full explanation has been proposed for the blue colour in natural beryl gemstones (aquamarine) despite it being well established that bluish-green synthetic aquamarines containing Fe turn blue when heated for 1 h at 400°C.A X-ray absorption near-edge spectroscopy (XANES) study at the Fe K-edge was performed on blue beryl crystals from Licungo pegmatite (Mozambique) to ascertain the speciation state of this colouring element, reported in blue sapphire (ideally Al2O3) as a mixture of Fe2+ and Fe3+ in octahedral coordination. The general trend of the spectra is the same when synchrotron radiation (SR) impinges along the c axis of the hexagonal crystal, as well as along the a axis with c vertical. Conversely, a shoulder in the absorption edge is noticed when the incident beam is perpendicular to c, with this axis horizontal in the polarization plane of the SR beam, a reverse in the relative intensities of the two post-edge features is simultaneously observed. Pre-edge features accounting for Fe speciation (valence plus coordination) are identical in all three situations. Considering previous approaches which account for polarization, an explanation is suggested for the special effects observed on the Fe K-edge XANES spectra of analysed blue beryl crystals. Ideas on the origin of the blue colour of this mineral are also presented.
Application of synchrotron methods to assess the uptake of roadway-derived Zn by earthworms in an urban soil
Authors: Lev S. M. , Landa E. R. , Szlavecz K. , Casey R. , Snodgrass J. 
Published: August 2008

AbstractThe impact of human activities on biogeochemical cycles in terrestrial environments is nowhere more apparent than in urban landscapes. Trace metals, collected on roadways and transported by storm water, may contaminate soils and sediments associated with storm water management systems. These systems will accumulate metals and associated sediments may reach toxic levels for terrestrial and aquatic organisms using the retention basins as habitat. The fate and bioavailability of these metals once deposited is poorly understood. Here we present results from a dose-response experiment that examines the application of synchrotron X-ray fluorescence methods (μ-SXRF) to test the hypothesis that earthworms will bio-accumulate Zn in a roadway-dust contaminated soil system providing a potential pathway for roadway contaminants into the terrestrial food web, and that the storage and distribution of Zn will change with the level of exposure reflecting the micronutrient status of Zn.Lumbricus friendiwas exposed to Zn-bearing roadway dust amended to a field soil at six target concentrations ranging from background levels (45 mg/kg Zn) to highly contaminated levels (460 mg/ kg Zn) designed to replicate the observed concentration range in storm-water retention basin soils. After a 30 day exposure, Zn storage in the intestine is positively correlated with dose and there is a change in the pattern of Zn storage within the intestine. This relationship is only clear when μ-SXRF Zn map data is coupled with a traditional toxicological approach, and suggests that the gut concentration inL. friendiis a better indicator of Zn bioaccumulation and storage than the total body burden.
Green rust as a precursor for magnetite: an in situ synchrotron based study
Authors: Sumoondur A. , Shaw S. , Ahmed I. , Benning L. G. 
Published: August 2008

AbstractIn this study, direct evidence for the formation of magnetite via a green rust intermediate is reported. The Fe(II) induced transformation of ferrihydrite, was quantified in situ and under O2-free conditions using synchrotron-based time-resolved energy dispersive X-ray diffraction. At pH 9 and Fe(II)/Fe(III) ratios of 0.5 and 1, rapid growth (6 min) of sulphate green rust and its subsequent transformation to magnetite was observed. Electron microscopy confirmed these results, showing the initial rapid formation of hexagonal sulphate green rust particles, followed by the corrosion of the green rust as magnetite growth occurred, indicating that the reaction proceeds via a dissolution-reprecipitation mechanism. At pH 7 and Fe(II)/Fe(III) ratio of 0.5, sulphate green rust was the stable phase, with no transformation to magnetite.
Antimony(V) complexing with O-bearing organic ligands in aqueous solution: an X-ray absorption fine structure spectroscopy and potentiometric study
Authors: Tella M. , Pokrovski G. S. 
Published: August 2008

AbstractThe stabilityand structure of aqueous complexes formed by pentavalent antimony (SbV) with simple organic ligands (acetic, adipic, oxalic, citric acids, catechol and xylitol) having O-functional groups (carboxyl, alcoholic hydroxyl, aliphatic and aromatic hydroxyl) typical of natural organic matter (NOM), were determined at 25°C from potentiometric and X-ray absorption fine structure spectroscopy (XAFS) measurements. In organic-free aqueous solutions, spectroscopic data are consistent with the dominant formation of SbV hydroxide species, Sb(OH)5 and Sb(OH)6-, at acid and near-neutral to basic pH, respectively. Potentiometric measurements demonstrate negligible complexing with mono-functional organic ligands (acetic) or those having non-adjacent carboxylic groups (adipic). In contrast, in the presence of poly-functional carboxylic, hydroxyl carboxylic acids and aliphatic and phenolic hydroxyl, SbV forms stable 1:1 or 1:3 complexes in coordination 6 with the studied organic ligands, over a wide pH range pertinent to natural waters (3 ≤ pH ≤ 9). The XAFS measurements show that in these species the central SbV atom has an octahedral geometry with 6 oxygen atoms from hydroxyl moieties and adjacent functional groups (O = C—OH and/or C—OH) of the ligand, forming bidendate chelate cycles. Stability constants for SbV-oxalate complexes generated from potentiometric experiments were used to model SbV complexing with di-carboxylic functional groups of natural humic acids. Our predictions show that in an aqueous solution of pH between 1 and 4 containing 1 μg/l of Sb and 5 mg/l of dissolved organic carbon (DOC), up to 15% of total dissolved Sb maybe bound to aqueous organic matter via di-carboxylic groups.
The metagenomics of biosilicification: causes and effects
Authors: Benning L. G. , Tobler D. J. 
Published: August 2008

AbstractIn order to determine the links between geochemical parameters controlling the formation of silica sinter in hot springs and their associated microbial diversity, a detailed characterisation of the waters and of in situ-grown silica sinters was combined with molecular phylogenetic analyses of the bacterial communities in Icelandic geothermal environments. At all but one site, the microorganisms clearly affected, and in part controlled, the formation of the macroscopic textures and structures of silica sinter edifices. In addition, the class and genera level phylogenetic diversity and distribution appeared to be closely linked to variations in temperature, salinity and pH regimes.
Weathering of sandstones studied from the composition of stream sediments of the Kupa River (Croatia)
Authors: Bilinski H. 
Published: August 2008

AbstractElemental compositions of the <2mm fraction of three sediments sampled along the Kupa River are presented. On plots of log(SiO2/Al2O3) vs. log(CaO+Na2O)/K2O, the sediments plot closest to average sandstone compositions. On plots of weathering indices A vs. B (Kronberg and Nesbitt, 1981) the sediments plot close to basalt, terrestrial crust and granite. X-ray diffraction of the <63 μm fraction suggests chlorite, vermiculite and mica are present as weathering products in the upper, middle and lower stream sediments. Depletion of some elements in the sediments suggests loss of elements from the sediments due to dissolution of minerals.
Chemical composition of enamel and dentine in modern reptile teeth
Authors: Dauphin Y. , Williams C. T. 
Published: August 2008

AbstractElemental distribution maps by wavelength-dispersive electron microprobe of enamel and dentine in modern crocodile teeth illustrate variations in both minor and major elements. Mg has the largest difference between the enamel and dentine, being enriched in the dentine. Mg, Ca and P are not homogeneously distributed in the dentine, but their distribution reflects changes during growth of the teeth. These variations in compositional differences of teeth from modern samples potentially can assist in establishing growth rates in fossil teeth samples, and thereby provide information on the physiology of extant species.