bluuebunny/crossref_metadata_2025_split huggingface dataset:
Instrument fracture in root canals ‐ where, why, when and what? A study from a student clinic
Authors: Ungerechts C. , Bårdsen A. , Fristad I. 
Published: April 2013

AbstractAimTo investigate the incidence of instrument fracture during nonsurgical root canal treatment performed by undergraduate dental students and to assess the outcome of the treatment if the remaining fragment was left or removed from the root canal.MethodologyA retrospective analysis was performed by reviewing assessment forms (n = 3854) filled out for each root canal treatment over a 10‐year period (1997–2006) at the University of Bergen, Norway. Based on the assessment forms, all instrument fractures and data concerning type and dimension of the fractured instruments were identified. Moreover, the affected tooth, root, root curvature and the vertical level of the fragment in the root canal were recorded. To assess the outcome of the root canal treatment, radiographs taken at follow‐ups were evaluated by two individual examiners.ResultsThe overall incidence of instrument fracture during the period was 1.0% on a tooth level. Instrument fracture occurred significantly more often in molars and in teeth rated as difficult preoperatively. Of all instrument fractures, 39.5% were located in the mesio‐buccal canals of molars, and 76.5% of the fragments were located apically. A significant high percentage of instruments of small apical diameter (sizes 006–015) fractured in relative straight root canals. The treatment was successful in 71.4% of the cases where the instrument fragment was removed, but only in 56.5% of the cases where the fragment remained in the root canal. Significantly more instruments were removed from teeth with a primary infection (P ≤ 0.05). The success rate for teeth with instrument fracture was 72.7% for vital teeth, 58.3% for primary infected teeth and 42.9% in retreatment cases.ConclusionsWithin the limits of the present study, the results indicate that the preoperative diagnosis is important for the final treatment outcome and that removal of the fragment is important in cases with primary infection.
Anatomical challenges, electronic working length determination and current developments in root canal preparation of primary molar teeth
Authors: Ahmed H. M. A. 
Published: April 2013

AbstractPaediatric endodontics is an integral part of dental practice that aims to preserve fully functional primary teeth in the dental arch. Pulpectomy of primary molars presents a unique challenge for dental practitioners. Negotiation and thorough instrumentation of bizarre and tortuous canals encased in roots programmed for physiological resorption are the main challenges for this treatment approach. Consequently, numerous in vitro and in vivo studies have been conducted to validate the application of some contemporary endodontic armamentarium for effective treatment in primary molars whilst maintaining favourable clinical outcomes. Electronic apex locators, rotary nickel–titanium files and irrigation techniques are at the forefront of endodontic armamentarium in paediatric dentistry. Hence, this review aims to map out the root and root canal morphology of primary molars, to discuss the application of electronic apex locators in primary molars and to provide an update on the preparation of their root canal systems.
Local anesthesia with lidocaine and prilocaine, using the tumescent technique, for the radiofrequency ablation of lower extremity varicose veins
Authors: Kendler Michael , Simon Jan C. , Wetzig Tino 
Published: April 2013

AbstractAimTo demonstrate the possible use of a tumescent solution containing lidocaine and prilocaine for radiofrequency‐assisted segmental thermal ablation and to reduce the need for postoperative analgesics.MethodsFifty patients (51 limbs) underwent radiofrequency‐assisted segmental thermal ablation (VNUS Closure FAST™) of insufficient great and small saphenous veins and phlebectomy. The amount of tumescent fluid injected was noted, and evaluation of pain reported on visual analog scale (VAS) and quantity of the postoperative analgesics used and their side effects were recorded one day and six weeks after the procedure.ResultsThe average amount of a tumescent fluid injected was 852 ml/patient (250–1470 ml). One day after surgery, 65% of the patients reported no pain (VAS 0), 27% reported a VAS of 1, and 4% reported a VAS of 2 on a scale of 0–10. Overall, 4% of the total patient population used analgesics after the procedure. Six weeks after the procedure, 84% of the patients reported no pain.ConclusionLocal anesthesia with lidocaine and prilocaine, and the tumescent technique, were found to be effective and safe modalities for radiofrequency ablation of varicose veins of the lower extremities.
Attributing Fuzzy Values to Nursing Diagnoses and Their Elements: The Specialists' Opinion
Authors: Jensen Rodrigo , de Almeida Lopes Monteiro da Cruz Diná , Gomes Luiz Celso , Lopes Maria Helena Baena de Moraes 
Published: April 2013

PurposeTo test the viability of to use specialists' opinions to establish degrees of membership between nursing diagnoses and its elements (defining characteristics or risk factors), based on the concepts of fuzzy sets theory. This strategy may feasibly mapping the specialist's knowledge on the diagnostic task.MethodsSpecialists were invited to reflect on the relationship between diagnoses and elements using linguistic variables, with a numerical representation.FindingsWe generated four matrices of 28 diagnoses and 62 elements. Out of 905 possibilities, we identified 286 relationships, represented in graphs.ConclusionsThe strategy was able to identify degrees of membership between nursing diagnoses and elements.ImplicationsIt seems that this method, if expanded, would contribute to refining and mapping the NANDA‐I terminology.ObjetivoTestar a viabilidade de utilizar a opinião de especialistas para estabelecer graus de pertinência entre diagnósticos de enfermagem e seus elementos (características definidoras ou fatores de risco), baseado nos conceitos da Teoria dos Conjuntos Fuzzy. Esta estratégia poderá viabilizar o mapeamento do conhecimento do especialista na tarefa diagnóstica.MétodosEspecialistas foram convidados a refletir na relação existente entre diagnósticos e elementos, utilizando variáveis linguísticas, com representação numérica.ResultadosForam geradas quatro matrizes de 28 diagnósticos e 62 elementos. Dentre 905 possibilidades, foram identificadas 286 relações, representadas em grafos.ConclusõesA estratégia foi adequada para identificar graus de pertinência entre diagnósticos de enfermagem e elementos.ImplicaçõesVislumbra‐se que esta metodologia, se expandida, contribua ao refinamento e mapeamento da classificação NANDA‐I.
Structure and Dielectric Properties of Re0.02Sr0.97TiO3 (Re = La,Sm,Gd,Er) Ceramics for High‐Voltage Capacitor Applications
Authors: Shen Zong‐Yang , Hu Qi‐Guo , Li Yue‐Ming , Wang Zhu‐Mei , Luo Wen‐Qin , Hong Yan , Xie Zhi‐Xiang , Liao Run‐Hua 
Published: April 2013

Rare–earth‐doped strontium titanate ceramics yielding the formula Re0.02Sr0.97TiO3 (Re–ST, Re = La, Sm, Gd, Er) were prepared by solid‐state reaction route. All Re–ST ceramics had single cubic perovskite structure similar to pure SrTiO3 (ST). The grain size of Re–ST ceramics dramatically decreased to 1–10 μm, depending on different rare‐earth elements, as compared to ~30 μm of pure ST. The relative dielectric constant of Re–ST ceramics (εr = 2750–4530 at 1 kHz) showed about 10–15 times higher than that of pure ST (εr = 300 at 1 kHz), whereas the dielectric loss of Re–ST ceramics still remained lower than 0.03 (at 1 kHz) at room temperature. Under 0–1.63 × 106 V/m bias electric field testing conditions, the εr of Re–ST ceramics at room temperature changed within 14%. The P–E results indicated that the Re–ST ceramics were linear dielectrics. Together with their relatively high breakdown strength (Eb > 1.4 × 107 V/m), the Re–ST ceramics could be very promising for high‐voltage capacitor applications. Meanwhile, the temperature stability of the εr of Re–ST ceramics was evaluated in a temperature range of −60°C–200°C.
Abruptio placentae in cynomolgus macaques (Macaca fascicularis): male bias
Authors: Schlabritz‐Loutsevitch N. , Schenone A. , Schenone M. , Gupta S. , Hubbard G. , Zhang J. , Mari G. , Dick E. 
Published: April 2013

AbstractBackgroundAbruptio placentae is a serious problem with a high rate of maternal and fetal mortality and documented sexual dimorphism in reoccurrence. Macaca fascicularis is a well‐described reproductive model; however, there are no data available regarding sexual dimorphism in abruptio placentae in these species.MethodsA retrospective study of pathology and medical records in a large colony of M. fascicularis was performed. Placental specimens were analyzed.ResultsThe incidence of placenta abruptio in the colony was 15.7/1000 births. In the abruptio placentae group, male fetuses had lower placental disk length and increased femur length compared with female fetuses. The feto‐pacental ratio and fetal weight were lower in the male fetuses in the abruption group compared with those in the stillbirth group without abruption placentae.ConclusionThis is the first documentation of male bias in placental and fetal development in abruptio placentae in non‐human primates.
Intracranial Extramedullary Hematopoiesis: A Rare Cause of Headaches
Authors: Singer Adam , Quencer Robert 
Published: April 2013

ABSTRACTBACKGROUNDEctopic bone marrow production, known as extramedullary hematopoiesis, may result in symptoms due to compression on normal structures. We present the multimodality imaging findings and subsequent management of a rare case of symptomatic extramedullary hematopoiesis within the calvarium.METHODSCase report.RESULTSA 54‐year‐old male with a history of myelofibrosis and no previous diagnosis of a headache disorder presented to the emergency department with worsening severe bilateral headaches. A nonenhanced CT of the brain was performed and diffuse extra‐axial nodular hyperdensities were visualized. MRI of the brain demonstrated diffuse extra‐axial avidly enhancing nodular masses, dural thickening and marked susceptibility. No paravertebral masses, typical for extramedullary hematopoiesis, were present in the chest or abdomen. Although the clinical team considered a biopsy to confirm the diagnosis, we suggested a noninvasive confirmatory test. The subsequent Tc99m sulfur colloid scan corroborated the diagnosis. The patient was then referred to radiation oncology for treatment.CONCLUSIONIn summary, extramedullary hematopoiesis is a hematologic compensatory disorder that rarely occurs within the CNS and may cause neurological compromise due to compression on underlying structures. The diagnosis can be made with noninvasive imaging and treated with low dose radiation therapy.
Correlations between polysomnographic and lateral airway radiograph measurements in paediatric obstructive sleep apnoea
Authors: Waters Karen , Kol‐Castro Chenda , Varghese Ajoy , Lam Lawrence T , Prelog Kristina , Cheng Alan 
Published: April 2013

AimTo evaluate the ability of lateral airway radiography (LAR) to assess adenoidal hypertrophy in children and correlate with the severity of obstructive sleep apnoea (OSA).MethodsThis cohort study was undertaken in 72 children who presented consecutively for evaluation of OSA to the outpatients of the Children's Hospital at Westmead. All children had LAR and overnight polysomnography (PSG). Five assessors, with varying experience, were blinded to the PSG results and independently analysed the LAR. Inter‐rater reliability was determined for four published assessment methods; Hibbert, Johannesson, Fujioka and Cohen and Konak. We then compared the four LAR results with PSG‐determined criteria for OSA.ResultsUsing intraclass correlations, inter‐rater correlations were moderate to high for all four standardised evaluations of LAR with values ranging from 0.51 to 0.96. With the radiologist taken as the ‘gold standard’, individual assessors ranged from 0.05 to 0.91. LAR correlated best with PSG determined obstructive apnoea hypopnea index and minimum oxygen saturation for the anterior airway measurement (Hibbert) with r‐values of −0.25 and 0.25 respectively (P < 0.05).ConclusionAmongst four methods of evaluating adenoid size, the anterior airway size correlated best with PSG variables of obstructive respiratory index and minimum oxygen saturation. However, the methods are not able to be used as a predictor for OSA.
Fossil grebes from theTruckeeFormation (Miocene) ofNevada and a new phylogenetic analysis ofPodicipediformes (Aves)
Authors: Ksepka Daniel T. , Balanoff Amy M. , Bell Michael A. , Houseman Michel D. 
Published: April 2013

Podicipediformes is a cosmopolitan clade of foot‐propelled diving birds that, despite inhabiting marine and lacustrine environments, have a poor fossil record. In this contribution, we describe three new grebe fossils from the diatomite beds of the Late Miocene Truckee Formation (10.2 ± 0.2 Ma) of Nevada (USA). Two postcranial skeletons and an associated set of wing elements indicate that at least two distinct grebe species occupied the large, shallow Lake Truckee during the Miocene. Phylogenetic analysis of morphological data supports a basal divergence between a clade uniting the dabchicks (Tachybaptus,Limnodytes,Poliocephalus) and a clade unitingPodilymbus,Rollandia,PodicepsandAechmophorus. Missing data, combined with a paucity of informative skeletal characters, make it difficult to place the Truckee grebes within either of these major clades. Given the weak projection of the cnemial crests compared with extant grebes, it also remains plausible that these specimens represent stem lineage grebes. Although more material is needed to resolve the phylogenetic position of the Truckee grebes, our analysis offers insight into the tempo of grebe evolution by placing the Miocene taxonThiornis sociatawithin the dabchick clade.Thiornis sociataprovides a minimum age calibration of 8.7 Ma for the basal divergence among dabchicks. Based on the recovery of a nonmonophyleticTachybaptusand placement of the Western Hemisphere ‘Tachybaptus’dominicusas the basal member of the otherwise exclusively Eastern Hemisphere dabchick clade, we resurrect the genusLimnodytesfor this extant species (Limnodytes dominicus). Our results also nest the large, long‐neckedAechmophorusgrebes within the genusPodiceps, as the sister taxon toPodiceps major.
Wetland megabias: ecological and ecophysiological filtering dominates the fossil record of hot spring floras
Authors: Channing Alan , Edwards Dianne 
Published: April 2013

AbstractSiliceous hot spring deposits form at Earth's surface above terrestrial hydrothermal systems, which create low‐sulphidation epithermal mineral deposits deeper in the crust. Eruption of hot spring waters and precipitation of opal‐A create sinter apron complexes and areas of geothermally influenced wetland. These provide habitat for higher plants that may be preserved in situ, by encrustation of their surfaces and permineralization of tissues, creating T0 plant assemblages. In this study, we review the fossil record of hot spring floras from subfossil examples forming in active hot spring areas, via fossil examples from the Cenozoic, Mesozoic and Palaeozoic to the oldest known hot spring flora, the Lower Devonian Rhynie chert. We demonstrate that the well‐known megabias towards wetland plant preservation extends to hot spring floras. We highlight that the record of hot spring floras is dominated by plants preserved in situ by permineralization on geothermally influenced wetlands. Angiosperms (members of the Cyperaceae and Restionaceae) dominate Cenozoic floras. Equisetum and gleicheniaceous ferns colonized Mesozoic (Jurassic) geothermal wetlands and sphenophytes and herbaceous lycophytes late Palaeozoic examples. Evidence of the partitioning of wetland hydrophytic and dryland mesophytic communities, a feature of active geothermal areas, is provided by well‐preserved and well‐exposed fossil sinter apron complexes, which record flooding of dryland environments by thermal waters and decline of local forest ecosystems. Such observations from the fossil record back‐up hypotheses based on active hot springs and vegetation that suggest removal of taphonomic filtering in hot spring environments is accompanied by an increase in ecological and ecophysiological filtering. To this end we also demonstrate that in the hot spring environment, the wetland bias extends beyond broad ecology. We show that ecosystems preserved from the Cenozoic to the Mesozoic provide clear evidence that the dominant plants preserved in situ by hot spring activity are also halophytic, tolerant of high pH and high concentrations of heavy metals. By extension, we hypothesize that this is also the case in Palaeozoic hot spring settings and extended to the early land plant flora of the Rhynie chert.
The taphonomy of colour in fossil insects and feathers
Authors: McNamara Maria E. 
Published: April 2013

AbstractColouration is an important multifunctional attribute of modern animals, but its evolutionary history is poorly resolved, in part because of our limited ability to recognize and interpret fossil evidence of colour. Recent studies on structural and pigmentary colours in fossil insects and feathers have illuminated important aspects of the anatomy, taphonomy, evolution and function of colour in these fossils. An understanding of the taphonomic factors that control the preservation of colour is key to assessing the fidelity with which original colours are preserved and can constrain interpretations of the visual appearance of fossil insects and theropods. Various analytical approaches can identify anatomical and chemical evidence of colour in fossils; experimental taphonomic studies inform on how colour alters during diagenesis. Preservation of colour is controlled by a suite of factors, the most important of which relate to the diagenetic history of the host sediment, that is, maximum burial temperatures and fluid flow, and subsurface weathering. Future studies focussing on key morphological and chemical aspects of colour preservation relating to cuticular pigments in insects and keratinous structures and nonmelanin pigments in feathers, for example, will resolve outstanding questions regarding the taphonomy of colour and will enhance our ability to infer original colouration and its functions in fossil insects and theropods.
Evidence of low levels of genetic diversity for the Phytophthora austrocedrae population in Patagonia, Argentina
Authors: Vélez M. L. , Coetzee M. P. A. , Wingfield M. J. , Rajchenberg M. , Greslebin A. G. 
Published: April 2013

Phytophthora austrocedrae is a recently discovered pathogen that causes severe mortality of Austrocedrus chilensis in Patagonia. The high level of susceptibility of the host tree, together with the distribution pattern of the pathogen, have led to the hypothesis that P. austrocedrae was introduced into Argentina. The aim of this study was to assess the population structure of P. austrocedrae isolates from Argentina in order to gain an understanding of the origin and spread of the pathogen. Genetic diversity was determined based on amplified fragment length polymorphisms (AFLPs). In total, 48 isolates of P. austrocedrae were obtained from infected A. chilensis trees, representing the geographical range of the host. Four primer combinations were used for the AFLP analysis. Of the 332 scored bands, 12% were polymorphic. Gene diversity (h) ranged from 0·01 to 0·03; the Shannon index (I) ranged from 0·01 to 0·04. A high degree of genetic similarity was observed among the isolates (pairwise S values = 0·958–1; 0·993 ± 0·009, mean ± SD). A frequency histogram showed that most of the isolate pairs were identical. Principal coordinate analysis using three‐dimensional plots did not group any of the isolates based on their geographical origin. The low genetic diversity (within and between sites) and absence of population structure linked to geographic origin, together with the aggressiveness of the pathogen and the disease progression pattern, suggest that P. austrocedrae might have been introduced into Argentina.
A numerical study of particle motion and two‐phase interaction in aeolian sand transport using a coupled large eddy simulation – discrete element method
Authors: Li Zhiqiang , Wang Yuan , Zhang Yang 
Published: April 2013

AbstractWind‐blown sand movement, considered as a particle‐laden two‐phase flow, was simulated by a new numerical code developed in the present study. The discrete element method was employed to model the contact force between sand particles. Large eddy simulation was used to solve the turbulent atmospheric boundary layer. Motions of sand particles were traced in the Lagrangian frame. Within the near‐surface region of the atmospheric boundary layer, interparticle collisions will significantly alter the velocity of sand. The sand phase is quite dense in this region, and its feedback force on fluid motion cannot be ignored. By considering the interparticle collision and two‐phase interaction, four‐way coupling was achieved in the numerical code. Profiles of sand velocity from the simulations were in good agreement with experimental measurements. The mass flux shows an exponential decay and is comparable to reported experimental and field measurements. The turbulence intensities and shear stress of sand particles were estimated from particle root‐mean‐square velocities. Distributions of slip velocity and feedback force were analysed to reveal the interactions between sand particles and the continuous fluid phase.
Changes in soil organic carbon and its chemical fractions under different tillage practices on loess soils of the Guanzhong Plain in north‐west China
Authors: Sun H. Y. , Wang C. X. , Wang X. D. , Rees R. M. 
Published: April 2013

AbstractOver the past 20 years, conservation tillage has been used on the loess plateau of north‐west China to improve the sustainability of local agriculture. There had been particular concern about loss of soil organic matter associated with traditional tillage. We examined the influence of four tillage treatments: conventional tillage (CT), subsoiling tillage (SST), rotary tillage (RT) and no‐tillage (NT), with two straw residue management treatments (return and removal) on the distribution with soil depth (0–20 cm, 20–40 cm) of total organic carbon, labile organic carbon (KMnO4‐C) and bound organic carbon. The study was carried out on a Loutu soil (Earth‐cumuli‐Orthic Anthrosol) over seven consecutive years of a winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) crop rotation. By the end of this period, conservation tillage (SST, RT and NT) led to greater storage of soil organic carbon (SOC) (22.7, 14.9 and 16.3% with straw return in contrast to 21.4, 15.8 and 12.3% with no straw return, respectively) compared with CT in the surface soil (0–20 cm). The reduced tillage treatments (SST and RT) both increased significantly the highly labile organic carbon (HLOC) content of the surface soil (50% in both SST and RT) and mildly labile organic matter (MLOC) (49.4 in SST and 53.5% in RT) when straw was removed. The largest pool of bound carbon was observed in the Humin‐C pool, and the smallest in the free humic acids C (FHA‐C) in each tillage treatment. Conservation tillage led to an increased content of FHA‐C and CHA‐C. Results from correlation analyses indicate that SOC enrichment might have resulted from the increase in HLOC, MLOC, FHA‐C and CHA‐C over a short period. Labile organic carbon was associated with the organic carbon that was more loosely combined with clay (FHA‐C and CHA‐C). We conclude that both SST and RT are effective in maintaining or restoring organic matter in Loutu soils in this region, and the effect is greater when they are used in combination with straw return.