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Schädler D, Becher T, Zick G, Frerichs I, Weiler N. A novel method to determine respiratory system mechanics during assisted ventilation. Intensive Care Med Exp 2015. [PMCID: PMC4796560 DOI: 10.1186/2197-425x-3-s1-a669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Zick G, Elke G, Schaedler D, Becher T, Balke L, Weiler N. Feasibility of ultrasound-based identification of correct central venous access using two acoustic windows. Intensive Care Med Exp 2015. [PMCID: PMC4798145 DOI: 10.1186/2197-425x-3-s1-a607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Becher T, Garcia i Tormo X. Addendum to “Electroweak Sudakov effects inW,Zandγproduction at large transverse momentum”. Int J Clin Exp Med 2015. [DOI: 10.1103/physrevd.92.073011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Baumann S, Becher T, Frambach D, Wenz H, Kirschning T, Borggrefe M, Rapp S, Akin I. [Hyponatremia-induced life-threatening cerebral edema after ecstasy use]. Med Klin Intensivmed Notfmed 2015; 111:547-50. [PMID: 26449216 DOI: 10.1007/s00063-015-0099-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/15/2015] [Accepted: 08/30/2015] [Indexed: 11/27/2022]
Abstract
Ecstasy, a psychoactive amphetamine derivative, is a popular party drug. We report the cases of 2 young adults who developed cerebral edema due to hyponatremia. One patient was released from the hospital without any sequelae, whereas the second patient died due to cerebral edema. Severe cases of symptomatic hyponatremia after ecstasy consumption are described in the literature with partially fatal clinical outcomes. Thus, physicians should be aware of early and consequent control of the sodium and choose an interdisciplinary treatment decision.
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Adler C, Berweck S, Lidzba K, Becher T, Staudt M. Mirror movements in unilateral spastic cerebral palsy: Specific negative impact on bimanual activities of daily living. Eur J Paediatr Neurol 2015; 19:504-9. [PMID: 26004994 DOI: 10.1016/j.ejpn.2015.03.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 03/15/2015] [Accepted: 03/16/2015] [Indexed: 11/24/2022]
Abstract
AIM Mirror movements are involuntary movements of the other hand during voluntary unimanual movements. Some, but not all children with unilateral spastic cerebral palsy (USCP) show this phenomenon. In this observational study, we investigated whether these mirror movements have a specific negative impact on bimanual activities of daily living. METHODS Eighteen children (six girls; age range, 6-16 years; mean age, 12 years 1 month; SD, 3 years 3 month) with USCP, nine with and nine without mirror movements, underwent the Jebsen Taylor Hand Function Test (unimanual capacity) and the Assisting Hand Assessment (bimanual performance). In addition, we measured the time the participants needed for the completion of five activities we had identified as particularly difficult for children with mirror movements. RESULTS Multivariate analysis demonstrated that mirror movements indeed have a specific negative impact on bimanual performance (Assisting Hand Assessment) and on the time needed for the completion of these five particularly difficult activities. This effect was independent from unimanual capacity. CONCLUSION Functional therapies in children with USCP and mirror movements should address this phenomenon.
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Becher T, Kott M, Schädler D, Vogt B, Meinel T, Weiler N, Frerichs I. Influence of tidal volume on ventilation inhomogeneity assessed by electrical impedance tomography during controlled mechanical ventilation. Physiol Meas 2015; 36:1137-46. [PMID: 26007294 DOI: 10.1088/0967-3334/36/6/1137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The global inhomogeneity (GI) index is a parameter of ventilation inhomogeneity that can be calculated from images of tidal ventilation distribution obtained by electrical impedance tomography (EIT). It has been suggested that the GI index may be useful for individual adjustment of positive end-expiratory pressure (PEEP) and for guidance of ventilator therapy. The aim of the present work was to assess the influence of tidal volume (VT) on the GI index values. EIT data from 9 patients with acute respiratory distress syndrome ventilated with a low and a high VT of 5 ± 1 (mean ± SD) and 9 ± 1 ml kg(-1) predicted body weight at a high and a low level of PEEP (PEEPhigh, PEEPlow) were analyzed. PEEPhigh and PEEPlow were set 2 cmH2O above and 5 cmH2O below the lower inflection point of a quasi-static pressure volume loop, respectively. The lower inflection point was identified at 8.1 ± 1.4 (mean ± SD) cmH2O, resulting in a PEEPhigh of 10.1 ± 1.4 and a PEEPlow of 3.1 ± 1.4 cmH2O. At PEEPhigh, we found no significant trend in GI index with low VT when compared to high VT (0.49 ± 0.15 versus 0.44 ± 0.09, p = 0.13). At PEEPlow, we found a significantly higher GI index with low VT compared to high VT (0.66 ± 0.19 versus 0.59 ± 0.17, p = 0.01). When comparing the PEEP levels, we found a significantly lower GI index at PEEPhigh both for high and low VT. We conclude that high VT may lead to a lower GI index, especially at low PEEP settings. This should be taken into account when using the GI index for individual adjustment of ventilator settings.
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Becher T, Frederix R, Neubert M, Rothen L. Automated NNLL [Formula: see text] NLO resummation for jet-veto cross sections. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2015; 75:154. [PMID: 25983650 PMCID: PMC4423915 DOI: 10.1140/epjc/s10052-015-3368-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 03/19/2015] [Indexed: 06/04/2023]
Abstract
In electroweak-boson production processes with a jet veto, higher-order corrections are enhanced by logarithms of the veto scale over the invariant mass of the boson system. In this paper, we resum these Sudakov logarithms at next-to-next-to-leading logarithmic accuracy and match our predictions to next-to-leading-order (NLO) fixed-order results. We perform the calculation in an automated way, for arbitrary electroweak final states and in the presence of kinematic cuts on the leptons produced in the decays of the electroweak bosons. The resummation is based on a factorization theorem for the cross sections into hard functions, which encode the virtual corrections to the boson production process, and beam functions, which describe the low-[Formula: see text] emissions collinear to the beams. The one-loop hard functions for arbitrary processes are calculated using the MadGraph5_aMC@NLO framework, while the beam functions are process independent. We perform the resummation for a variety of processes, in particular for [Formula: see text] pair production followed by leptonic decays of the [Formula: see text] bosons.
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Bläser D, Pulletz S, Becher T, Schädler D, Elke G, Weiler N, Frerichs I. Unilateral empyema impacts the assessment of regional lung ventilation by electrical impedance tomography. Physiol Meas 2014; 35:975-83. [DOI: 10.1088/0967-3334/35/6/975] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Becher T, Bell G. Enhanced nonperturbative effects through the collinear anomaly. PHYSICAL REVIEW LETTERS 2014; 112:182002. [PMID: 24856689 DOI: 10.1103/physrevlett.112.182002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Indexed: 06/03/2023]
Abstract
We show that nonperturbative effects are logarithmically enhanced for transverse-momentum-dependent observables such as qT spectra of electroweak bosons in hadronic collisions and jet broadening at e+ e- colliders. This enhancement arises from the collinear anomaly, a mechanism characteristic for transverse observables, which induces logarithmic dependence on the hard scale in the product of the soft and collinear matrix elements. Our analysis is based on an operator product expansion and provides, for the first time, a systematic, model-independent way to study nonperturbative effects for this class of observables. For the case of jet broadening, we relate the leading correction to the nonperturbative shift of the thrust distribution.
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Schranz C, Becher T, Schädler D, Weiler N, Möller K. Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation. Physiol Meas 2014; 35:383-97. [PMID: 24499739 DOI: 10.1088/0967-3334/35/3/383] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (pI), inspiration and expiration time (tI, tE) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal pI and adequate tE can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's 'optimized' settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end-expiratory pressure.
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Becher T, Weise S, Röhrig A, Messing-Jünger M. Schmerzbeeinträchtigtes Kleinkind mit Torticollis nach Sturz vom Trampolin. Monatsschr Kinderheilkd 2014. [DOI: 10.1007/s00112-013-2983-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Baumann S, Frambach D, Huseynov A, Becher T, Boecker C, Behnes M, Rapp S, Papavassiliu T, Borggrefe M, Akin I. The value of multimodality imaging for detection, characterisation and management of a wall adhering structure in the right atrium. IMAGES IN PAEDIATRIC CARDIOLOGY 2014; 16:1-7. [PMID: 26236367 PMCID: PMC4521328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The case presents a wall adherent structure in the right atrium in a young patient with peripheral t-cell lymphoma followed by successful prolonged lysis therapy resulting in the resolution of the thrombus is presented. This case highlights the utility of multimodality imaging in an accurate assessment of the right atrium thrombus and the effectiveness of prolonged lysis therapy.
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Borusiak P, Langer T, Tibussek D, Becher T, Jenke A, Cagnoli S, Karenfort M. YouTube as a Source of Information for Children with Paroxysmal Episodes. KLINISCHE PADIATRIE 2013; 225:394-7. [DOI: 10.1055/s-0033-1353142] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Schranz C, Becher T, Schädler D, Weiler N, Möller K. Model-Based Ventilator Settings in Pressure Controlled Ventilation. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-S/bmt-2013-4425/bmt-2013-4425.xml. [PMID: 24043203 DOI: 10.1515/bmt-2013-4425] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Becher T, Garcia i Tormo X. Electroweak Sudakov effects inW,Zandγproduction at large transverse momentum. Int J Clin Exp Med 2013. [DOI: 10.1103/physrevd.88.013009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Kretschmer J, Riedlinger A, Becher T, Schädler D, Weiler N, Möller K. A Family of Physiological Models to Simulate Human Gas Exchange. BIOMED ENG-BIOMED TE 2013; 58 Suppl 1:/j/bmte.2013.58.issue-s1-N/bmt-2013-4353/bmt-2013-4353.xml. [DOI: 10.1515/bmt-2013-4353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Müller J, Friedrich M, Becher T, Braunstein J, Kupper T, Berdel P, Gravius S, Rohrbach F, Oldenburg J, Mayer G, Pötzsch B. Monitoring of plasma levels of activated protein C using a clinically applicable oligonucleotide-based enzyme capture assay. J Thromb Haemost 2012; 10:390-8. [PMID: 22236082 DOI: 10.1111/j.1538-7836.2012.04623.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Human-activated protein C (APC) is a serine protease with anticoagulant, anti-inflammatory and cytoprotective functions. This feature renders APC to be a promising vascular-inflammatory biomarker. OBJECTIVE The aim of the present study was the development and validation of a technique that allows the measurement of APC plasma levels under practical laboratory conditions. METHODS/PATIENTS Based on the APC-binding ssDNA aptamer HS02-52G we developed an oligonucleotide-based enzyme capture assay (OECA) that quantifies aptamer-captured APC through hydrolysis rates of a fluorogenic peptide substrate. After optimization of pre-analytical conditions, plasma APC levels were measured in healthy individuals and patients undergoing hip replacement surgery. RESULTS AND CONCLUSION A combination of APC-OECA with an aprotinin-based quenching strategy allowed APC analysis with a limit of detection as low as 0.022 ± 0.005 ng mL(-1) (0.39 ± 0.10 pmol L(-1)) and a limit of quantification of 0.116 ± 0.055 ng mL(-1) (2.06 ± 0.98 pmol L(-1)). While APC plasma levels in healthy individuals fell below the quantifiable range of the APC-OECA platform, levels substantially increased in patients undergoing hip replacement surgery reaching peak values of up to 12 ng mL(-1) (214 pmol L(-1)). When normalized to the amount of thrombin generated, interindividual variabilities in the APC generating capacity were observed. In general, with a turn-around time from blood sampling to generation of test results of < 7 h, the APC-OECA platform allows sensitive and rapid determination of circulating APC levels under pathological conditions.
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Becher T, Lorentzen C, Schwartz MD. Resummation for W and Z production at large p{T}. PHYSICAL REVIEW LETTERS 2012; 108:012001. [PMID: 22304256 DOI: 10.1103/physrevlett.108.012001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Indexed: 05/31/2023]
Abstract
Soft-collinear effective theory is used to perform threshold resummation for W and Z production at large transverse momentum to next-to-next-to-leading logarithmic accuracy including matching to next-to-leading fixed-order results. The results agree very well with data from the Tevatron, and predictions are made for the high-p{T} spectra at the LHC. While the higher-log terms are of moderate size, their inclusion leads to a substantial reduction of the perturbative uncertainty. With these improvements, the parton distribution function uncertainties now dominate the error on the predicted cross section.
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Becher T. ["My child frequently twists his head...!" Sandifer syndrome - not just a rare occurrence]. KINDERKRANKENSCHWESTER : ORGAN DER SEKTION KINDERKRANKENPFLEGE 2011; 30:153-156. [PMID: 21744568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Sellei RM, Lank C, Becher T, Knobe M, Rüger M, Spies CKG, Schmitt T, Peters J, Erli HJ. [An optimised assessment of "severely injured patients" for the documentation of road traffic accident black spots]. ZEITSCHRIFT FUR ORTHOPADIE UND UNFALLCHIRURGIE 2011; 149:279-87. [PMID: 21391178 DOI: 10.1055/s-0030-1270734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
INTRODUCTION The success of traffic safety improvement strategies is based on documentation. Analysis and remedy of accident black spots in addition to improvements in automobile production involve the work of traffic engineers, politicians, traffic regulations, police, and medical care. To create priorities, the traffic statistics differentiate accidents in a 3-class system in relation to severe accidents: slightly injured, severely injured and fatally injured (death). This study assesses the validity of the existing classification of "severely injured" compared with the actual injury severity. MATERIAL AND METHOD We analysed accidents resulting in 182 "severely injured" people in one year in a city model. A synchronisation of anonymous police documentation with the medical notes of admitted casualties which were validated by established trauma scores and medical classification was undertaken. A correlation analysis of length of stay should give indications of the actual injury severity. RESULTS The study group showed a ubiquitous range of age, sex and injuries despite a relatively low case number. The range of MAIS, ISS and NACA index scores shows the inhomogeneity of the people classified as "severely injured". 70 % of the study group revealed ISS < 16 which means that they are not polytraumatised patients. The correlation analysis according to Spearman certifies the validity of these scores (r MAIS/NACA = 0.645 and r ISS/NACA = 0.592). The further differentiation on the basis of MAIS, ISS and NACA showed that 51 % of the study group should be classified as slightly injured and 83 % of these were discharged in less than 5 days. CONCLUSION This study shows that the traffic safety classification of "severely injured" people is not sufficient and most severely injured people are not even approximately recorded. We propose that a new continuous link system between police and medical data will be inevitable for future improvements in traffic safety. The use of established trauma scores and a differentiated look at lengths of stay could be an option.
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Becher T, Neubert M. Infrared singularities of scattering amplitudes in perturbative QCD. PHYSICAL REVIEW LETTERS 2009; 102:162001. [PMID: 19518699 DOI: 10.1103/physrevlett.102.162001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Indexed: 05/27/2023]
Abstract
An exact formula is derived for the infrared singularities of dimensionally regularized scattering amplitudes in massless QCD with an arbitrary number of loops and legs. It is based on the conjecture that the anomalous-dimension matrix of n-jet operators in soft-collinear effective theory is fully determined by three functions of alpha{s}, which can be extracted from known perturbative results for the quark and gluon form factors. This allows us to predict the three-loop coefficients of all 1/;{k} poles for arbitrary n-parton scattering amplitudes, generalizing existing two-loop results.
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Becher T, Neubert M. Analysis of B(B-->Xsgamma) at next-to-next-to-leading order with a cut on photon energy. PHYSICAL REVIEW LETTERS 2007; 98:022003. [PMID: 17358598 DOI: 10.1103/physrevlett.98.022003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Indexed: 05/14/2023]
Abstract
By combining a recent estimate of the total B-->X(s)gamma branching fraction at O(alpha(s)2) with a detailed analysis of the effects of a cut E(gamma)>or=1.6 GeV on photon energy, a prediction for the partial B-->Xsgamma branching fraction at next-to-next-to-leading order in renormalization-group improved perturbation theory is obtained, in which contributions from all relevant scales are factorized. The result B(B-->Xsgamma)=(2.98+/-0.26) x 10(-4) is about 1.4 sigma lower than the experimental world average. This opens a window for significant new physics contributions in rare radiative B decays.
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Becher T, Neubert M. Threshold resummation in momentum space from effective field theory. PHYSICAL REVIEW LETTERS 2006; 97:082001. [PMID: 17026292 DOI: 10.1103/physrevlett.97.082001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Indexed: 05/12/2023]
Abstract
Methods from soft-collinear effective theory are used to perform the threshold resummation of Sudakov logarithms for the deep-inelastic structure function F2(x,Q2) in the end-point region x-->1 directly in momentum space. An explicit all-order formula is derived, which expresses the short-distance coefficient function C in the convolution F2 = C multiply sign in circle phi q in terms of Wilson coefficients and anomalous dimensions defined in the effective theory. Contributions associated with the physical scales Q2 and Q2(1-x) are separated from nonperturbative hadronic physics in a transparent way. A crucial ingredient to the momentum-space resummation is the exact solution to the integro-differential evolution equation for the jet function, which is derived. The methods developed in this Letter can be applied to many other hard QCD processes.
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Freyse EJ, Knospe S, Becher T, El Hag O, Göke B, Fischer U. Glucagon-like peptide-1 has no insulin-like effects in insulin-dependent diabetic dogs maintained normoglycemic and normoinsulinemic. Metabolism 1999; 48:134-7. [PMID: 9920158 DOI: 10.1016/s0026-0495(99)90023-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A pharmacological concentration of glucagon-like peptide-1 (GLP-1) in the insulin-deficient state clearly decreases the blood glucose level. Therefore, this study was designed to evaluate a putatively relevant effect of the gastrointestinal peptide as an adjuvant to insulin replacement therapy. GLP-1 (GLP-1(7-36) amide 10 pmol x kg(-1) x min(-1)) was infused intravenously over 8 hours in nine fasting, C-peptide-negative diabetic dogs. The animals were under normoglycemic control by glucose-controlled insulin infusion (GCII) during the night before and during GLP-1 administration. During the paired control tests, the animals received saline infusion instead of GLP-1. In addition to the insulin infusion rates required to maintain normoglycemia, hormones, metabolites, and the turnover rates for glucose (6-3H-glucose), alanine (U-14C-alanine), and urea (15N2-urea) were measured during the final 2 hours of GLP-1 administration. Circulating plasma GLP-1 levels increased from 3+/-1 to 17+/-7 pmol/L. There was no significant difference in the insulin infusion rate between the experimental and control groups (0.43+/-0.05 v. 0.40+/-0.05 mU x kg(-1) x h(-1), average over the entire interval). Glycemia was maintained at a practically identical level (4.9+/-0.3 v. 4.8+/-0.4 mmol/L). Also, the concentration of plasma insulin-which was not hyperinsulinemic--and pancreatic glucagon remained unaltered. We found no appreciable effect of GLP-1 on glucose production and metabolic clearance, alanine turnover and the formation of glucose from alanine (1.8+/-0.2 v. 1.4+/-0.2 micromol x kg(-1) x min(-1), or the urea production rate as a measure of overall amino acid catabolism (4.1+/-0.4 v. 4.1+/-0.4 micromol x kg(-1) x min(-1)). Thus, no conclusive adjuvant effect of GLP-1 was ascertained in insulin-treated diabetic dogs under normoglycemic control.
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