bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-performance digital predistortion test platform development for wideband RF power amplifiers
Authors: Guan Lei , Kearney Ray , Yu Chao , Zhu Anding 
Published: March 2013

In this paper, a complete design procedure, together with robust system validation approaches, is presented for implementing a high-performance re-configurable digital predistortion (DPD) test platform for compensating for nonlinear distortion and memory effects induced by radio frequency (RF) power amplifiers (PAs) in the transmitters of modern wireless communication systems. This hardware and software co-operated test system not only enables effective validation for DPD algorithm development, but also provides a high-performance and reliable hardware-based linearization test platform. The experimental test was applied on a medium power Doherty amplifier, which was designed for 3 G/4 G wireless communication base stations. By applying our DPD algorithms on the proposed platform, more than 30 dB improvements in adjacent channel power ratio can be achieved for Universal Mobile Telecommunications System and long-term evolution signal excitations.
Rotational alignment effects in NO(X) + Ar inelastic collisions: An experimental study
Authors: Brouard M. , Chadwick H. , Eyles C. J. , Hornung B. , Nichols B. , Aoiz F. J. , Jambrina P. G. , Stolte S. 
Published: March 2013

Rotational angular momentum alignment effects in the rotationally inelastic collisions of NO(X) with Ar have been investigated at a collision energy of 66 meV by means of hexapole electric field initial state selection coupled with velocity-map ion imaging final state detection. The fully quantum state resolved second rank renormalized polarization dependent differential cross sections determined experimentally are reported for a selection of spin-orbit conserving and changing transitions for the first time. The results are compared with the findings of previous theoretical investigations, and in particular with the results of exact quantum mechanical scattering calculations. The agreement between experiment and theory is generally found to be good throughout the entire scattering angle range. The results reveal that the hard shell nature of the interaction potential is predominantly responsible for the rotational alignment of the NO(X) upon collision with Ar.
Interleukin‐6: Possible biological roles during exercise
Authors: Reihmane Dace , Dela Flemming 
Published: March 2013

AbstractInterleukin‐6 (IL‐6) is a multifunctional cytokine that exerts its modulatory effects on cells that express membrane bound IL‐6 receptors; however, IL‐6 in a complex with soluble IL‐6R can bind to any cell that express glycoprotein 130 (gp130). Thus, all cell types may respond to the pro‐ as well as anti‐inflammatory properties of IL‐6. Since the first report of acute exercise‐induced increase in plasma IL‐6 in the early 1990s, scientists have tried to elucidate the factors that influence the magnitude of change of plasma IL‐6, as well as the possible biological roles of this cytokine. Evidence suggests that exercise intensity and duration as well as the form of contraction (e.g. eccentric or concentric) and muscle damage all influence IL‐6 response to acute exercise. However, data on training status and performance on plasma IL‐6 concentration changes during exercise are more inconclusive, as discussed in this review. In the last decade, most of the studies have focused on IL‐6 as an ‘energy sensor’ possibly secreted by skeletal muscle that activates glycogenolysis in the liver and lipolysis in fat tissue in order to provide muscle with the growing energy demands during exercise.
Respiratory triggered 4D cone‐beam computed tomography: A novel method to reduce imaging dose
Authors: Cooper Benjamin J. , O'Brien Ricky T. , Balik Salim , Hugo Geoffrey D. , Keall Paul J. 
Published: March 2013

Purpose:A novel method called respiratory triggered 4D cone‐beam computed tomography (RT 4D CBCT) is described whereby imaging dose can be reduced without degrading image quality. RT 4D CBCT utilizes a respiratory signal to trigger projections such that only a single projection is assigned to a given respiratory bin for each breathing cycle. In contrast, commercial 4D CBCT does not actively use the respiratory signal to minimize image dose.Methods:To compare RT 4D CBCT with conventional 4D CBCT, 3600 CBCT projections of a thorax phantom were gathered and reconstructed to generate a ground truth CBCT dataset. Simulation pairs of conventional 4D CBCT acquisitions and RT 4D CBCT acquisitions were developed assuming a sinusoidal respiratory signal which governs the selection of projections from the pool of 3600 original projections. The RT 4D CBCT acquisition triggers a single projection when the respiratory signal enters a desired acquisition bin; the conventional acquisition does not use a respiratory trigger and projections are acquired at a constant frequency. Acquisition parameters studied were breathing period, acquisition time, and imager frequency. The performance of RT 4D CBCT using phase based and displacement based sorting was also studied. Image quality was quantified by calculating difference images of the test dataset from the ground truth dataset. Imaging dose was calculated by counting projections.Results:Using phase based sorting RT 4D CBCT results in 47% less imaging dose on average compared to conventional 4D CBCT. Image quality differences were less than 4% at worst. Using displacement based sorting RT 4D CBCT results in 57% less imaging dose on average, than conventional 4D CBCT methods; however, image quality was 26% worse with RT 4D CBCT.Conclusions:Simulation studies have shown that RT 4D CBCT reduces imaging dose while maintaining comparable image quality for phase based 4D CBCT; image quality is degraded for displacement based RT 4D CBCT in its current implementation.
Comparative incidence of concussion and return to play time in two Canadian minor hockey groups over the 2011–2012 season
Authors: Rhine D J , Lamvohee T 
Published: March 2013

ObjectiveReport concussion incidence and Return to Play (RTP) times over a minor hockey season (2011–12) in two sub-groups, a community hockey association (A) and a private hockey academy (B).DesignRetrospective, cohort study.SettingElite hockey players from A and B.Subjects354 subjects in two sub-groups. A: 222 (191 Males/31 Females). B: 132 (114 Males/18 Females).InterventionSubjects were educated and baseline tested at the start of the 2011–12 season using Symptom Inventory, SCAT2, BESS and neuro-cognitive testing. The Zurich 2008 RTP protocol was utilised. Subjects were followed with serial testing until recovered to baseline or within 5% of baseline. Medical authorisation was given to RTP.Outcome MeasuresThe incidence of concussion and the average RTP in the two groups.ResultsA. Concussion incidence –Overall 23% ▸ A 18% (n=39) ▸ B 32% (n=42)B. RTP (Average No. Days to RTP)Overall: 22 ▸ A: 27 ▸ B: 14ConclusionsConcussion incidence approximated that reported by Echlin. The higher incidence in the B group reflects the experience of coaches and full-time athletic therapists in recognising and dealing with concussions, and a willingness to report concussion injury. Overall RTP time was longer in both groups than the previously reported 12.8 days average. For B, the RTP time was less than A (14 vs 27 days), reflecting daily access to supportive care (athletic therapists and physician), daily access to the gym for Steps 2 and 3, and daily ice-time for Steps 4 and 5 of the RTP protocol.
Day of injury assessment of sport-related concussion
Authors: McCrea Michael , Iverson Grant L , Echemendia Ruben J , Makdissi Michael , Raftery Martin 
Published: March 2013

ObjectiveTo conduct a critical review of the literature on instruments currently used in the assessment of sport-related concussion on the day of injury.Data sourcesComputerised searches of the literature posted to MEDLINE, PubMed, CINAHL, PsychInfo and Cochrane Library from 1 January 1982 through 21 August 2012. Key words and medical embedded subheadings (MeSH) terms relevant to sport-related concussion were applied, which identified 577 articles.Study selectionIn addition to MeSH term and key word criteria, a study was included in the analysis if the article: (1) was published in English, (2) represented original research, (3) pertained to sport-related concussion (ie, not non-sports traumatic brain injury), (4) included assessment or diagnostic data collected within 24 h of the injury event and (5) involved human research. A total of 41 studies qualified for review.Data extractionAll articles were examined to determine if the study met the additional requirements for inclusion. A standardised method was used to document critical elements of the study design, population, tests employed and key findings.Data synthesisA large number of studies were analysed that reported data from testing conducted within 24 h of injury. These studies collectively demonstrated that a number of instruments are capable of measuring the acute effects of concussion across several domains, such as symptoms, cognition and balance.ResultsRelating to specific assessment domains are compiled in separate tables and an interpretive summary of the findings is provided.ConclusionsSeveral well-validated tests are appropriate for use in the assessment of acute concussion in the competitive sporting environment. These tests provide important data on the symptoms and functional impairments that clinicians can incorporate into their diagnostic formulation, but they should not solely be used to diagnose concussion.
Advances in neuropsychological assessment of sport-related concussion
Authors: Echemendia Ruben J , Iverson Grant L , McCrea Michael , Macciocchi Stephen N , Gioia Gerard A , Putukian Margot , Comper Paul 
Published: March 2013

ObjectiveTo critically review the literature from the past 12 years regarding the following key issues in sports-related neuropsychological assessment: (1) the advantages and disadvantages of different neuropsychological assessment modalities; (2) the evidence for and against the current paradigm of baseline/postinjury testing; (3) the role of psychological factors in the evaluation and management of concussion; (4) advances in the neuropsychological assessment of children; (5) multi-modal assessment paradigms; (6) the role of the neuropsychologist as part of the sports healthcare team and (6) the appropriate administration and interpretation of neuropsychological tests.DesignTargeted computerised literature review (MEDLINE, PubMed, CINAHL and PsychInfo) from 2000 to the present using key words: neuropsychological, neurocognitive, assessment, testing, concussion and sports.ResultsMore than 2600 articles were identified using key word searches of the databases, including many duplicates. Several books were also reviewed. The articles were pared down for review if they specifically addressed the key areas noted above.ConclusionsTraditional and computerised neuropsychological tests are useful in the evaluation and management of concussion. Brief cognitive evaluation tools are not substitutes for formal neuropsychological assessment. At present, there is insufficient evidence to recommend the widespread routine use of baseline neuropsychological testing. Although scant, research suggests that psychological factors may complicate and prolong recovery from concussion in some athletes. Age-appropriate symptom scales for children have been developed but research into age-appropriate tests of cognitive functions lags behind. Neuropsychologists are uniquely qualified to interpret neuropsychological tests and can play an important role within the context of a multifaceted-multimodal approach to manage sports-related concussions.
The effects of rest and treatment following sport-related concussion: a systematic review of the literature
Authors: Schneider Kathryn J , Iverson Grant L , Emery Carolyn A , McCrory Paul , Herring Stanley A , Meeuwisse Willem H 
Published: March 2013

ObjectiveTo evaluate the evidence for rest, treatment, and rehabilitation following sport-related concussion (SRC).Data sourcesPubMed, CINAHL, PsychInfo, Cochrane Controlled Trials Registers, Health STAR, Sport Discus, EMBASE, Web of Science, and ProQuest.Study selectionArticles were included if they met the following criteria: original research, reported SRC as a source of injury, and evaluated the effect of rest or treatment.Data extractionStudy design, participants, treatment, outcome measures, and key findings.Data synthesisThree studies met the inclusion criteria for evaluating the effects of rest and twelve for treatment. Low-intensity aerobic exercise may be of benefit.ConclusionsThe current evidence evaluating the effect of rest and treatment following SRC is sparse. An initial period of rest may be of benefit. Low-level exercise and multimodal physiotherapy may be of benefit for those who are slow to recover. There is a strong need for high level studies evaluating the effects of rest and treatment following SRC.
What are the most effective risk-reduction strategies in sport concussion?
Authors: Benson Brian W , McIntosh Andrew S , Maddocks David , Herring Stanley A , Raftery Martin , Dvořák Jiří 
Published: March 2013

AimTo critically review the evidence to determine the efficacy and effectiveness of protective equipment, rule changes, neck strength and legislation in reducing sport concussion risk.MethodsElectronic databases, grey literature and bibliographies were used to search the evidence using Medical Subject Headings and text words. Inclusion/exclusion criteria were used to select articles for the clinical equipment studies. The quality of evidence was assessed using epidemiological criteria regarding internal/external validity (eg, strength of design, sample size/power, bias and confounding).ResultsNo new valid, conclusive evidence was provided to suggest the use of headgear in rugby, or mouth guards in American football, significantly reduced players’ risk of concussion. No evidence was provided to suggest an association between neck strength increases and concussion risk reduction. There was evidence in ice hockey to suggest fair-play rules and eliminating body checking among 11-years-olds to 12-years-olds were effective injury prevention strategies. Evidence is lacking on the effects of legislation on concussion prevention. Equipment self-selection bias was a common limitation, as was the lack of measurement and control for potential confounding variables. Lastly, helmets need to be able to protect from impacts resulting in a head change in velocities of up to 10 and 7 m/s in professional American and Australian football, respectively, as well as reduce head resultant linear and angular acceleration to below 50 g and 1500 rad/s2, respectively, to optimise their effectiveness.ConclusionsA multifactorial approach is needed for concussion prevention. Future well-designed and sport-specific prospective analytical studies of sufficient power are warranted.
What evidence exists for new strategies or technologies in the diagnosis of sports concussion and assessment of recovery?
Authors: Kutcher Jeffrey Scott , McCrory Paul , Davis Gavin , Ptito Alain , Meeuwisse Willem H , Broglio Steven P 
Published: March 2013

ObjectiveThe purpose of this critical review is to summarise the evidence for the following technologies/strategies related to diagnosing or managing sports-related concussion: quantitative EEG, functional neuroimaging, head impact sensors, telemedicine and mobile devices.Data sourcesMEDLINE, PubMed, Cochrane Controlled Trials Registers, SportDiscus, EMBASE, Web of Science and ProQuest databases. Primary search keywords were concussion, sports concussion and mild traumatic brain injury. The keywords used for secondary, topic specific searches were quantitative electroencephalography, qEEG, functionalMRI, magnetoencephalography, near-infrared spectroscopy, positron emission tomography, single photon emissionCT, accelerometer, impact sensor, telemetry, remote monitoring, robotic medicine, telemedicine, mobile device, mobile phone, smart phone and tablet computer.ResultsThe primary search produced 8567 publications. The secondary searches produced nine publications that presented original data, included a comparison group in the study design and involved sports-related concussion. Four studies spoke to the potential of qEEG as a diagnostic or management tool, while five studies addressed the potential of fMRI to be used in the same capacity.ConclusionsEmerging technologies and novel approaches that aid in sports concussion diagnosis and management are being introduced at a rapid rate. While some technologies show promise, their clinical utility remains to be established.
Immune Reconstitution and Risk of Hodgkin's Lymphoma among a Sample of HIV-Infected Male Veterans
Authors: M Kowalkowski , E Chiao 
Published: March 2013

Abstract
Purpose: In contrast to certain AIDS-defining cancers, the incidence of Hodgkin's lymphoma (HL) has increased since the introduction of combined antiretroviral therapy (cART). Although HIV-associated HL has been strongly linked to the Epstein-Barr virus, the causes for the increased incidence of HL in the cART era remain unclear. The aim of this study was to evaluate the effect of cART utilization and possible immune reconstitution inflammatory syndrome (IRIS), through monitoring the activity of immunologic measures (e.g., nadir CD4 prior to cART, recent CD4, percent of time with undetectable HIV viral load), on the incidence of HL among a sample of HIV-infected male veterans. Methods: We performed a retrospective cohort study utilizing data from the Veterans Affairs HIV Clinical Case Registry (VA-CCR) from 1985–2010. HL cases were identified using ICD-9 codes. Women were excluded due to low numbers. We also excluded individuals without identifiable CD4 or viral load measurement, no cART use, &lt;90 days of follow-up, and prevalent HL cases occurring prior to or within 90 days of HIV diagnosis. We analyzed the relationship between immunologic measures associated with cART utilization and the incidence of HL, calculated in multivariable Poisson regression models adjusted for demographic and time-varying immunologic covariates. Results: The final sample included 31,596 cART users, contributing 288,968 person-years and 219 HL cases (IR = 76 per 100,000 person-years). In multivariable regression models, the risk of HL was higher among veterans with recent CD4 &lt;200 copies/cell (IRR = 1.57, 95%CI = 1.05–2.34) and between 200–350 copies/cell (IRR = 1.68, 95%CI = 1.17–2.40), compared to individuals with &gt;350 copies/cell. Also, HL risk was increased among veterans within 1 year (IRR = 2.38, 95%CI = 1.60–3.53) and 1–2 years (IRR = 1.89, 95%CI = 1.27–2.82) after cART initiation, compared to &gt;2 years. Conclusion: Recent CD4 counts &lt;350 copies/cell were associated with an increased risk of HL among cART users. Additionally, risk of HL was increased in the 2 years directly following cART initiation. Findings indicate an EBV-associated IRIS may function in HL development in HIV-infected individuals.
Coronary Wave Energy
Authors: De Silva Kalpa , Foster Paul , Guilcher Antoine , Bandara Asela , Jogiya Roy , Lockie Tim , Chowiencyzk Phil , Nagel Eike , Marber Michael , Redwood Simon , Plein Sven , Perera Divaka 
Published: March 2013

Background—
Revascularization after acute coronary syndromes provides prognostic benefit, provided that the subtended myocardium is viable. The microcirculation and contractility of the subtended myocardium affect propagation of coronary flow, which can be characterized by wave intensity analysis. The study objective was to determine in acute coronary syndromes whether early wave intensity analysis-derived microcirculatory (backward) expansion wave energy predicts late viability, defined by functional recovery.

Methods and Results—

Thirty-one patients (58±11 years) were enrolled after non-ST elevation myocardial infarction. Regional left ventricular function and late-gadolinium enhancement were assessed by cardiac magnetic resonance imaging, before and 3 months after revascularization. The backward-traveling (microcirculatory) expansion wave was derived from wave intensity analysis of phasic coronary pressure and velocity in the infarct-related artery, whereas mean values were used to calculate hyperemic microvascular resistance. Twelve-hour troponin T, left ventricular ejection fraction, and percentage late-gadolinium enhancement mass were 1.35±1.21 µg/L, 56±11%, and 8.4±6.0%, respectively. The infarct-related artery backward-traveling (microcirculatory) expansion wave was inversely correlated with late-gadolinium enhancement infarct mass (
r
=–0.81;
P
<0.0001) and strongly predicted regional left ventricular recovery (
r
=0.68;
P
=0.001). By receiver operating characteristic analysis, a backward-traveling (microcirculatory) expansion wave threshold of 2.8 W m
–2
s
–2
×10
5
predicted functional recovery with sensitivity and specificity of 0.91 and 0.82 (AUC 0.88). Hyperemic microvascular resistance correlated with late-gadolinium enhancement mass (
r
=0.48;
P
=0.03) but not left ventricular recovery (
r
=–0.34;
P
=0.07).

Conclusions—
The microcirculation-derived backward expansion wave is a new index that correlates with the magnitude and location of infarction, which may allow for the prediction of functional myocardial recovery. Coronary wave intensity analysis may facilitate myocardial viability assessment during cardiac catheterization.