bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pre-ignition and ‘super-knock’ in turbo-charged spark-ignition engines
Authors: Kalghatgi Gautam T , Bradley Derek 
Published: February 2012

Earlier studies of pre-ignitions at hot surfaces are first reviewed. The concept of a critical radius of a hot pocket of gas, closely related to the laminar flame thickness, that is necessary to initiate a propagating flame, has been used successfully to predict relative tendencies of different fuel–air mixtures to pre-ignite. As the mixture is compressed, the thickness of potential laminar flames decreases, and when this becomes of the order of the thermal sheath thickness at the hottest surface, pre-ignition can occur there, creating a propagating flame. Measured engine pre-ignition ratings are shown to correlate well with laminar flame thicknesses. Predictions are made concerning the effects of changes in intake temperature and pressure on the pre-ignition of different fuels. A growing current concern is occasional gas-phase, autoignitive, pre-ignitions that can occur in turbo-charged engines, giving rise to very severe autoignition and knock. It is concluded from the evidence of engine pressure records and autoignition delay times of the mixtures that such pre-ignitions have not arisen from autoignition of the fuel, but of a mixture with a smaller autognition delay time than stoichiometric n-heptane–air. One possibility is that autoignition occurs at hot spots containing some lubricating oil. It is shown that such pre-ignitions, particularly with catalytic enhancement, could initiate a propagating flame, rather than autoignitive propagation. In the later, much more severe autoignition arising after pre-ignition, autoignitive propagation velocities at a hot spot are estimated from computed values of the ignition delay times and assumed reactivity gradients in the fuel–air mixture at the hot spot. The severity of the associated pressure pulse is dependent upon the ratios [Formula: see text], of the acoustic speed to the localised autoignitive velocity, and [Formula: see text], of the residence time of the acoustic wave in the hot spot to the short excitation time in which most of the chemical energy is released. The regime in which a localised detonation can be generated in the hot spot is defined by a peninsula on a plot of [Formula: see text] against [Formula: see text]. A locus is plotted on this figure corresponding to the growing measured intensities of the engine knock as the pressure increases. This is based on computed autoignition delays and excitation times, for an appropriate surrogate fuel. These changes are characterised by [Formula: see text] tending to unity and [Formula: see text] tending to ever-higher values, with increasingly intense, localised, developing detonations.
Impact reconstruction from damage to pedal and motorcycle helmets
Authors: McIntosh Andrew S , Patton Declan A 
Published: February 2012

Pedal and motorcycle helmets offer a high level of protection to the wearer’s head. There is a need to review and assess the performance offered by helmets, so that helmet design and test standards can be optimized. One input into this process is crash reconstruction. Helmeted crash cases can be collected and examined, leading to insights into impact severity, helmet performance and injury outcomes. However, it is unclear to what extent residual helmet damage reflects the impact characteristics. This paper addresses this issue using controlled laboratory impact tests. Two pedal cycle and three motorcycle helmet models were tested with an ‘M’ size headform in impact energy attenuation tests from 1 m, 2 m and 2.5 m. Headform acceleration, impact force and post-impact deformation were measured. The dynamic deformations were measured with three methods: video, kinetic energy and an analytical approach using impact force and liner yield stress. All five models offered highly repeatable performance in terms of impact energy attenuation and acceleration management in radial impacts across the impact severities. The results showed that the Standards Australia certified helmets provided impact protection to the head in impacts that greatly exceeded the impact energy attenuation performance requirements of those standards. The residual and dynamic deformation measurements were correlated with drop height and headform acceleration for pedal cycle helmets. The results indicate that the residual deformation observed in a pedal cycle helmet collected from a crash can be used to estimate the impact severity and, after undertaking exemplar impact tests on the same model helmet, the head impact acceleration. However, the residual deformation measured on the three motorcycle helmets was not correlated with the drop height, which indicated that, within the limits of this study, estimating crash severity from motorcycle helmet damage is not reliable.
Clinical significance of bone changes in osteoarthritis
Authors: Neogi Tuhina 
Published: February 2012

Osteoarthritis (OA), the most common form of arthritis, is now understood to involve all joint tissues, with active anabolic and catabolic processes. Knee OA in particular is considered to be a largely mechanically-driven disease. As bone adapts to loads by remodeling to meet its mechanical demands, bone alterations likely play an important role in OA development. Subchondral bone changes in bone turnover, mineralization, and volume result in altered apparent and material density of bone that may adversely affect the joint’s biomechanical environment. Subchondral bone alterations such as bone marrow lesions (BMLs) and subchondral bone attrition (SBA) both tend to occur more frequently in the more loaded knee compartments, and are associated with cartilage loss in the same region. Recently, MRI-based 3D bone shape has been shown to track concurrently with and predict OA onset. The contributions of structural abnormalities to the clinical manifestations of knee OA are becoming better understood as well. While a structure-symptom discordance in knee OA is thought to exist, such observations do not take into account all potential factors that can contribute to between-person differences in the pain experience. Using novel methodology, pain fluctuation has been associated with changes in BMLs, synovitis and effusion. SBA has also been associated with knee pain, but the relationship of osteophytes to pain has been conflicting. Understanding the pathophysiologic sequences and consequences of OA pathology will guide rational therapeutic targeting. Importantly, rational treatment targets require understanding what structures contribute to pain as pain is the reason patients seek medical care.
Molecular distinctions between pediatric and adult mature B-cell non-Hodgkin lymphomas identified through genomic profiling
Authors: Deffenbacher Karen E. , Iqbal Javeed , Sanger Warren , Shen Yulei , Lachel Cynthia , Liu Zhongfeng , Liu Yanyan , Lim Megan S. , Perkins Sherrie L. , Fu Kai , Smith Lynette , Lynch James , Staudt Louis M. , Rimsza Lisa M. , Jaffe Elaine , Rosenwald Andreas , Ott German K. , Delabie Jan , Campo Elias , Gascoyne Randy D. , Cairo Mitchell S. , Weisenburger Dennis D. , Greiner Timothy C. , Gross Thomas G. , Chan Wing C. 
Published: February 2012

Abstract
Burkitt lymphoma (BL) predominates in pediatric patients, whereas diffuse large B-cell lymphoma (DLBCL) is uncommon. In contrast to adults, BL and DLBCL are treated similarly in children and both entities have superior outcomes in children compared with adults. Gene expression profiling (GEP) and miRNA expression profiling clearly differentiated pediatric DLBCL from BL, forming distinct clusters regardless of patient age. However, pathway analysis of GEP data identified minor differences between corresponding pediatric and adult tumors. Predominance (6:1) of the germinal center B-cell subtype to activated B-cell subtype was found among pediatric DLBCL. Two cases were molecularly classified as primary mediastinal B-cell lymphoma. We observed frequent abnormalities in 8q24 in pediatric DLBCL, including MYC rearrangement in 31% (5 of 16) and gain or amplification in 50% (6 of 12) nonrearranged cases. MYC rearrangement was present in 96% (23 of 24) BL cases. Array-based CGH analysis identified abnormalities that are shared between adult and pediatric DLBCL (+12q15, +19q13, −6q), and abnormalities unique to the pediatric cases (−4p14, −19q13.32, +16p11.2), suggesting distinct pathogenetic mechanisms relative to age. Elucidation of the underlying target genes may provide insight into factors that modulate outcome and could provide potential novel therapeutic targets with less toxicity for pediatric patients with B-cell non-Hodgkin lymphoma.
Recent advances in the pathogenesis and clinical evaluation of pulmonary fibrosis
Authors: Margaritopoulos G.A. , Romagnoli M. , Poletti V. , Siafakas N.M. , Wells A.U. , Antoniou K.M. 
Published: February 2012

Interstitial lung diseases (ILDs) are a group of heterogeneous disorders, either idiopathic or associated with injurious or inflammatory causes, in which the major site of damage is the lung interstitium. For a long time, knowledge regarding pathogenesis was trivial and there were difficulties in diagnosing and subsequently treating these diseases.During the past decade, however, there has been an impressive development in the field of ILDs. Idiopathic pulmonary fibrosis, the most common and fatal form of ILD, was initially believed to be due to an inflammatory response to unknown lung injury, whereas nowadays it is believed to be the result of multiple injuries at different sites of the lung followed by aberrant repair.The integration of clinical, radiological and histological data, namely a multidisciplinary team (MDT) approach, has provided grounds for a more accurate diagnosis of ILDs, and helped the identification of different entities and development of different therapeutic approaches. However, because of the complexity of ILDs, even this approach may fail to establish a confident diagnosis.How should the clinician behave in this case and what are the pitfalls of the MDT approach? In addition, since diagnosis is the major predictor of prognosis, are there any other tools available to predict prognosis?
Pulmonary hypertension: the science behind the disease spectrum
Authors: Wilkins M.R. 
Published: February 2012

Pulmonary hypertension (PH) is a complex, multifactorial disorder divided into five major subtypes according to pathological, pathophysiological and therapeutic characteristics. Although there are distinct differences between the PH categories, a number of processes are common to the pathology of all subtypes.Vasoconstriction, as a result of endothelial dysfunction and an imbalance in the levels of vasoactive mediators, is a well-characterised contributory mechanism. Excessive cell proliferation and impaired apoptosis in pulmonary vessels leading to structural remodelling is most evident in pulmonary arterial hypertension (PAH), and several factors have been implicated, including mitochondrial dysfunction and mutations in bone morphogenetic protein receptor type 2. Inflammation plays a key role in the development of PH, with increased levels of many cytokines and chemokines in affected patients. Exciting insights into the role of angiogenesis and bone marrow-derived endothelial progenitor cells in disease progression have also recently been revealed. Furthermore, there is increasing interest in changes in the right ventricle in PH and the role of metabolic abnormalities.Despite considerable progress in our understanding of the molecular mechanisms of PH, further research is required to unravel and integrate the molecular changes into a better understanding of the pathophysiology of PH, particularly in non-PAH, to put us in a better position to use this knowledge for improved treatments.
How to detect disease progression in pulmonary arterial hypertension
Authors: Vachiéry J-L. , Yerly P. , Huez S. 
Published: February 2012

Pulmonary arterial hypertension (PAH) is a rapidly progressive disease, ultimately leading to right heart failure and death. Accumulating evidence indicates that intervention early in disease progression results in better outcomes than delaying treatment.In this review we will discuss the assessments and strategies that can be used to monitor disease progression and guide clinical management. Many tools, such as symptoms, functional classification, exercise capacity, haemodynamic measures, findings on cardiac imaging and levels of biomarkers, have shown to be prognostic for survival both at diagnosis and during treatment. However, attempts to define goal thresholds have produced a variety of results.Several groups have developed risk calculators to estimate individual patients' mortality risk, but the accuracy of these tools across different patient populations remains unknown. What is clear is the importance of regularly assessing a range of parameters and then tailoring treatment goals to each patient. In addition, the use of a multidisciplinary team approach is crucial in order to support patients through all aspects of managing their condition.There is still an urgent need for prospective collaborative initiatives to assess novel goals and improve treatment strategies that would allow physicians to personalise and optimise clinical management for their patients with PAH.
State-of-the-art chronic thromboembolic pulmonary hypertension diagnosis and management
Authors: Jenkins D. , Mayer E. , Screaton N. , Madani M. 
Published: February 2012

Chronic thromboembolic pulmonary hypertension (CTEPH) is a debilitating disease caused by chronic obstruction of pulmonary artery branches following episodes of pulmonary embolism and incomplete thrombus resolution. The prognosis of patients with CTEPH is poor unless an early diagnosis is made and treatment is initiated.Chest radiography and echocardiography are used in the initial assessment of suspected pulmonary hypertension. A diagnosis of CTEPH may be confirmed by the presence of a mismatched wedge-shaped perfusion deficit during ventilation/perfusion scintigraphy or characteristic findings during multi-slice computed tomography (CT) angiography, including a mosaic perfusion pattern, dilatation of proximal pulmonary arteries and right heart chambers, and the presence of vascular stenosis or obstruction.Prior to possible surgery, pulmonary angiography remains the definitive diagnostic technique, indicating the site and accessibility of the obstruction. However, many centres utilise CT and magnetic resonance imaging following recent advances in these noninvasive techniques. Haemodynamic evaluationviaright heart catheterisation is also mandatory, as pulmonary vascular resistance is the most important determinant of both prognosis and the risk associated with pulmonary endarterectomy surgery.Accurate CTEPH diagnosis and characterisation of its extent and distribution are imperative to allow the prompt initiation of treatment, particularly surgical pulmonary endarterectomy in eligible patients.
Performance evaluation of unified medical language system®'s synonyms expansion to query PubMed
Authors: Griffon Nicolas , Chebil Wiem , Rollin Laetitia , Kerdelhue Gaetan , Thirion Benoit , Gehanno Jean-François , Darmoni Stéfan Jacques 
Published: February 2012

Abstract

Background
PubMed is the main access to medical literature on the Internet. In order to enhance the performance of its information retrieval tools, primarily non-indexed citations, the authors propose a method: expanding users' queries using Unified Medical Language System' (UMLS) synonyms i.e. all the terms gathered under one unique Concept Unique Identifier.

Methods
This method was evaluated using queries constructed to emphasize the differences between this new method and the current PubMed automatic term mapping. Four experts assessed citation relevance.

Results
Using UMLS, we were able to retrieve new citations in 45.5% of queries, which implies a small increase in recall. The new strategy led to a heterogeneous 23.7% mean increase in non-indexed citation retrieved. Of these, 82% have been published less than 4 months earlier. The overall mean precision was 48.4% but differed according to the evaluators, ranging from 36.7% to 88.1% (Inter rater agreement was poor: kappa = 0.34).

Conclusions
This study highlights the need for specific search tools for each type of user and use-cases. The proposed strategy may be useful to retrieve recent scientific advancement.
A new method of lower extremity immobilization in radiotherapy
Authors: Zheng Xuhai , Dai Tangzhi , Shu Xiaochuan , Pu Yuanxue , Feng Gang , Li Xuesong , Liao Dongbiao , Du Xiaobo 
Published: February 2012

Abstract
We developed a new method for immobilization of the fix lower extremities by using a thermoplastic mask, a carbon fiber base plate, a customized headrest, and an adjustable angle holder. The lower extremities of 11 patients with lower extremity tumors were immobilized by this method. CT simulation was performed for each patient. For all 11 patients, the device fit was suitable and comfortable and had good reproducibility, which was proven in daily radiotherapy.
Effectiveness of Chinese herbal medicine in treating liver fibrosis: a systematic review and meta-analysis of randomized controlled trials
Authors: Cheung Fan , Feng Yibin , Wang Ning , Yuen Man-Fung , Tong Yao , Wong Vivian Taam 
Published: February 2012

Abstract

Background
The studies on the effectiveness of Chinese herbal medicines (CHM) in treating liver fibrosis (LF) were not consistent. This study aims to systematically review the effectiveness of CHM on treating LF patients.

Methods
Databases including MEDLINE, AMED, EMBASE, The Cochrane Central Register of Controlled Trials, China National Knowledge Infrastructure, TCMOnline, Chinese Biomedical Literature Database, and Chinese Medical Current Contents were searched up to March 2011. Randomized controlled trials (RCTs) involving LF patients receiving CHM, Western medicine, combined CHM and Western medicine compared with placebo, Western medicine or no intervention were included. LF markers including serum hyaluronic acid (HA), laminin (LN), procollagen type III (PC-III), type IV collagen (IV-C), matrix metalloproteinase (MMP), and tissue inhibitors of metalloproteinase (TIMP) were measured as primary outcomes. Liver biochemistry, including alanine aminotransferase (ALT) and aspartarte aminotransferase (AST), and improvement of related clinical symptoms were measured as secondary outcomes. Risk of bias of allocation sequence, allocation concealment, blinding, incomplete outcome data, selective outcome reporting, and other biases were assessed.

Results
Twenty-three RCTs with 2123 participants were analyzed in subgroups of types of comparison and study quality. Fifteen studies were graded as good quality. CHM alone and combined with Western medicine showed significant improvements in HA, LN, PC-III and IV-C compared with Western medicine alone. However, there were no significant differences observed between CHM and placebo treatments.

Conclusion
The current inconclusive results in determining the effectiveness of CHM treatment on LF, due to the poor methodological quality and high heterogeneity of the studies, suggests that large RCTs using standardized Chinese medicine syndrome diagnosis and CHM formulae with longer follow-up are required for further evaluation.
Frequency of disease-associated and other nuclear autoantibodies in patients of the German network for systemic scleroderma: correlation with characteristic clinical features
Authors: Mierau Rudolf , Moinzadeh Pia , Riemekasten Gabriela , Melchers Inga , Meurer Michael , Reichenberger Frank , Buslau Michael , Worm Margitta , Blank Norbert , Hein Rüdiger , Müller-Ladner Ulf , Kuhn Annegret , Sunderkötter Cord , Juche Aaron , Pfeiffer Christiane , Fiehn Christoph , Sticherling Michael , Lehmann Percy , Stadler Rudolf , Schulze-Lohoff Eckhard , Seitz Cornelia , Foeldvari Ivan , Krieg Thomas , Genth Ekkehard , Hunzelmann Nicolas 
Published: February 2012

Abstract
Introduction
In the present study, we analysed in detail nuclear autoantibodies and their associations in systemic sclerosis (SSc) patients included in the German Network for Systemic Scleroderma Registry.

Methods
Sera of 863 patients were analysed according to a standardised protocol including immunofluorescence, immunoprecipitation, line immunoassay and immunodiffusion.

Results
Antinuclear antibodies (ANA) were detected in 94.2% of patients. In 81.6%, at least one of the autoantibodies highly associated with SSc or with overlap syndromes with scleroderma features was detected, that is, anti-centromere (35.9%) or anti-topoisomerase I (30.1%), followed in markedly lower frequency by antibodies to PM-Scl (4.9%), U1-ribonucleoprotein (U1-RNP) (4.8%), RNA polymerases (RNAPs) (3.8%), fibrillarin (1.4%), Ku (1.2%), aminoacyl-transfer RNA synthetases (0.5%), To (0.2%) and U11-RNP (0.1%). We found that the simultaneous presence of SSc-associated autoantibodies was rare (1.6%). Furthermore, additional autoantibodies were detected in 55.4% of the patients with SSc, of which anti-Ro/anti-La, anti-mitochondrial and anti-p25/p23 antibodies were most frequent. The coexistence of SSc-associated and other autoantibodies was common (43% of patients). SSc-associated autoantibodies disclosed characteristic associations with clinical features of patients, some of which were previously not acknowledged.

Conclusions
This study shows that five autoantigens (that is, centromere, topoisomerase I, PM-Scl, U1-RNP and RNAP) detected more than 95% of the known SSc-associated antibody responses in ANA-positive SSc patients and characterise around 79% of all SSc patients in a central European cohort. These data confirm and extend previous data underlining the central role of the determination of ANAs in defining the diagnosis, subset allocation and prognosis of SSc patients.
Fluid management and risk factors for renal dysfunction in patients with severe sepsis and/or septic shock
Authors: Muller Laurent , Jaber Samir , Molinari Nicolas , Favier Laurent , Larché Jérôme , Motte Gilles , Lazarovici Sonia , Jacques Luc , Alonso Sandrine , Leone Marc , Constantin Jean Michel , Allaouchiche Bernard , Suehs Carey , Lefrant Jean-Yves ,   the AzuRéa Group
Published: February 2012

Abstract
Introduction
The causative role of new hydroxyethyl starch (HES 130/0.4) in renal dysfunction frequency (a > 50% increase in serum creatinine or need for renal replacement therapy (RRT)) remains debated. Using the database of a multicenter study focusing on patients with severe sepsis and septic shock, the present study aimed at identifying factors associated with the occurrence of renal dysfunction.

Methods
Among the 435 patients in a multicenter study of patients with severe sepsis and septic shock in 15 Southern French ICUs, 388 patients surviving after 24 hour, without a history of renal failure were included. Factors associated with renal dysfunction and RRT were isolated using a multivariate analysis with logistic regression.

Results
Renal dysfunction was reported in 117 (33%) patients. Ninety patients required RRT. Among study participants, 379 (98%) were administered fluids in the first 24 hours of management: HES 130/0.4 only (n = 39), crystalloids only (n = 63), or both HES 130/0.4 and crystalloids (n = 276). RRT was independently associated with the need for vasopressors and the baseline value of serum creatinine in the first 24 hours. Multivariate analysis indicated that male gender, SAPS II score, being a surgical patient, lack of decrease in SOFA score during the first 24 hours, and the interventional period of the study were independently associated with renal dysfunction. Mortality increased in the presence of renal dysfunction (48% versus 24%, P < 0.01).

Conclusions
Despite being used in more than 80% of patients with severe sepsis and/or septic shock, the administration of HES 130/0.4 in the first 24 hours of management was not associated with the occurrence of renal dysfunction.