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On the sampling strategies and models for measuring diffusion exchange with a double diffusion encoding sequence

Magnetic Resonance Letters 2023年第3期3卷 232-247,I0003页

作者： Alfredo Ordinola Shan Cai peter lundberg Ruiliang Bai Evren Ozarslan Department of Biomedical Engineering(IMT) Link oping UniversityLink opingS-58185Sweden Department of Radiation Physics Department of HealthMedicine and Caring Sciences(HMV)Link oping UniversityLink opingS-58183Sweden Center for Medical Image Science and Visualization(CMIV) Link oping UniversityLink opingS-58185Sweden School of Medicine Zhejiang University866 Yuhangtang RdHangzhou310058China

Water exchange between the different compartments of a heterogeneous specimen can be characterized via diffusion magnetic resonance imaging(dMRI).Many analysis frameworks using dMRI data have been proposed to describe exchange,often using a double diffusion encoding(DDE)stimulated echo *** such as diffusion exchange weighted imaging(DEWI)and the filter exchange and rapid exchange models,use a specific subset of the full space DDE *** this work,a general representation of the DDE signal was employed with different sampling schemes(namely constant b1,diagonal and anti-diagonal)from the data reduction models to estimate exchange.A near-uniform sampling scheme was proposed and compared with the other sampling *** filter exchange and rapid exchange models were also applied to estimate exchange with their own subsampling *** subsampling schemes and models were compared on both simulated data and experimental data acquired with a benchtop MR *** synthetic data,the diagonal and near-uniform sampling schemes performed the best due to the consistency of their estimates with the ground *** experimental data,the shifted diagonal and near-uniform sampling schemes outperformed the others,yielding the most consistent estimates with the full space *** results suggest the feasibility of measuring exchange using a general representation of the DDE signal along with variable sampling *** future studies,algorithms could be further developed for the optimization of sampling schemes,as well as incorporating additional properties,such as geometry and diffusion anisotropy,into exchange frameworks.

关键词： Diffusion MRI Water exchange Sampling schemes Double diffusion encoding

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使用罗斯比中心海洋模型检测波罗的海次盆地的周转时间

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AMBIO－人类环境杂志 2004年第4期33卷 236-239页

作者： Bror Jnsson peter A.lundberg Kristofer Ds 许天虎斯德哥尔摩大学气象系斯德哥尔摩大学

尤其在判断气候变化可能带来的影响时,事实证明有必要对受到显著的外部影响的有限海域的水更新速度进行评估。随SWECLIM项目一起,上述工作已在波罗的海的两个生态敏感的次盆地(即:里加湾和格但斯克湾)中开展。为此目的,我们已分别以质... 详细信息

尤其在判断气候变化可能带来的影响时,事实证明有必要对受到显著的外部影响的有限海域的水更新速度进行评估。随SWECLIM项目一起,上述工作已在波罗的海的两个生态敏感的次盆地(即:里加湾和格但斯克湾)中开展。为此目的,我们已分别以质量平衡收支和拉格朗日轨迹线为基础,采用了两种方法上不同的做法。与采用拉格朗日技术获取的结果相比,事实证明,在作为一个在形态上受到极大约束的盆地的里加湾中,使用这种箱状模型方法非常合适,而在将它用于以更加开阔的地形条件为特点的格但斯克湾时却表现出一些不足。

关键词：波罗的海技术获取周转罗斯项目收支实证盆地海洋模型迹线

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Portal vein thrombosis in liver transplantation: radiologic evaluation, risk factors, and occult diagnosis

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Hepatoma Research 2016年第1期2卷 36-41页

作者： Adam Hauch Carl Winkler Eric Katz peter W.lundberg Mary Killackey Anil S.Paramesh Luis A.Balart Nathan J.Shores Martin Moehlen Ward Miller Douglas P.Slakey Joseph F.Buell Bob H.Saggi Tulane Transplant Institute Tulane University School of MedicineNew OrleansLA 70112USA Department of Gastroenterology Section of HepatologyTulane University School of MedicineNew OrleansLA 70112USA

Aim:Portal vein thrombosis(PVT)in the liver transplant recipient poses many ***,the risk factors and effects on outcomes of PVT are not ***:This study analyzed the experience with PVT in liver transplant program from 2007 to *** included the effectiveness of PVT diagnostics and its risk factors using logistical *** primary endpoints were Kaplan-Meir patient and graft *** secondary endpoints were the length of stay(LOS),transfusion rate,and overall *** predictors of survival were identified using a Cox’s proportional hazards ***:Two hundred and sixteen consecutive liver transplant recipients were examined,and 30(13.8%)had either a total or partial *** hundred and five patients had imaging within 1 year of liver transplantation with only 7(23.3%)of the 30 PVTs identified *** sensitivity(4.8-50%)and negative predictive values(10.5-22.2%)were ***,age significantly predicted PVT[P=0.037/hazard ratio(HR)=0.95].Ninety-day-patient and graft survival for PVT was similar at 6 months,although 1-year survival was significantly lower.“Occult”PVT was not associated with inferior *** for end-stage liver disease score>25(P=0.001,HR=0.49/P=0.004,HR=0.52)and age>60 years(P=0.017,HR=0.64/P=0.013,HR=0.67)were significant predictors of patient and graft *** the transfusion rate was significantly greater with PVT,LOS,and morbidity were ***:Older recipients had a greater likelihood of *** studies were not effective at excluding PVT,and occult diagnosis did not affect the *** was not an independent predictor of mortality or graft loss,but was associated with greater blood loss but not increased LOS or morbidity.

关键词： Advanced age graft survival patient survival post-transplant outcomes resource utilization

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Running Temperature and Mechanical Stability of Grease as Maintenance Parameters of Railway Bearings

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International Journal of Automation and computing 2010年第2期7卷 160-166页

作者： Jan lundberg Aditya Parida peter Sderholm Division of Operation and Maintenance Engineering Lule University of Technology

Spherical roller bearings in railway car wheels are critical components whose failure may have catastrophic consequences. The present study aims to analyse the mechanical stability of greases and temperature of bearings as indicators for condition-based bearing maintenance. The performed case study includes nine fully-formulated commercial greases examined in the wheel bearings of five ore cars operated in northern Scandinavia. The studied ore cars travelled a distance of about 300 000 km during a period of three years. Small samples of the greases were taken on eight occasions to test their mechanical stability. In addition, the temperatures of the bearings were continuously recorded. After the test period, the wear, electrical damage, and corrosion of the bearings were examined. One of the findings is that the shear stress of the grease at a certain shear velocity （the certain yieldstress （CEY） value） is a good maintenance indicator and is highly dependent on the grease type. The bearing＇s wear, electrical damage and corrosion also depend on the grease type. However, no oxidation of the greases was identified. The paper also outlines a systematic methodology to determine an overall maintenance indicator for railway roller bearings which is based on the field measurements.

关键词： Maintenance mechanical stability railway roller bearings grease lubrication.

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Rectal nitric oxide as biomarker in the treatment of inflammatory bowel disease: Responders versus nonresponders

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World Journal of Gastroenterology 2006年第21期12卷 3386-3392页

作者： Tryggve Ljung Sofie lundberg Mark Varsanyi Catharina Johansson peter T Schmidt Max Herulf Jon O lundberg Per M Hellstr(o|¨)m Department of Gastroenterology and Hepatology Karolinska University Hospital Site SolnaStockholmSweden Department of Physiology and Pharmacology Karolinska Institutet StockholmSweden

AIM： To explore rectal nitric oxide （NO） as biomarker of treatment response in ulcerative colitis （UC） and Crohn＇s disease （CD）, and examine relationships between rectal NO, mucosal expression of NO synthases （NOS）, and pro-inflammatory cytokines. METHODS： Twenty-two patients with UC and 24 with CD were monitored during steroid treatment. Rectal NO levels were measured and clinical activities were assessed on days 1, 3, 7 and 28. Mucosal presence of NOS and pro-inflammatory cytokines were analyzed by immunohistochemistry and RT-PCR. RESULTS： Active UC and CD displayed markedly increased rectal NO levels （10950 ± 7610 and 5 040 ± 1 280 parts per billion （ppb）, respectively） as compared with the controls （154 ± 71 ppb, P 〈 0.001）. Rectal NO correlated weakly with disease activity in both UC and CD （r = 0.34 for UC and r = 0.48 for CD, P 〈 0.01）. In 12 patients, a steroid-refractory course led to colectomy. These patients had only slightly increased NO levels （UC： 620 ± 270 ppb; CD： 1260 ± 550 ppb） compared to those with a therapeutic response （UC： 18860 ± 530 ppb, P 〈 0.001, CD： 10060 ± 3200 ppb, P 〈 0.05）. CONCLUSION： Rectal NO level is a useful biomarker of treatment response in IBD as low NO levels predicts a poor clinical response to steroid treatment.

关键词： Crohn's disease CytokJnes Nitric oxide Steroids Ulcerative colitis

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Bone without borders-Monetite-based calcium phosphate guides bone formation beyond the skeletal envelope

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Bioactive Materials 2023年第1期19卷 103-114页

作者： Furqan A.Shah Martina Jolic Chiara Micheletti Omar Omar Birgitta Norlindh Lena Emanuelsson Håkan Engqvist Thomas Engstrand Anders Palmquist peter Thomsen Department of Biomaterials Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden Department of Materials Science and Engineering McMaster UniversityHamiltonOntarioCanada Department of Engineering Sciences Applied Materials Science SectionUppsala UniversityUppsalaSweden Department of Reconstructive Plastic Surgery Karolinska University HospitalStockholmSweden

Calcium phosphates(CaP)represent an important class of osteoconductive and osteoinductive *** proof-of-concept,we show how a multi-component CaP formulation(monetite,beta-tricalcium phosphate,and calcium pyrophosphate)guides osteogenesis beyond the physiological *** a sheep model,hollow dome-shaped constructs were placed directly over the occipital *** 12 months,large amounts of bone(~75%)occupy the hollow space with strong evidence of ongoing *** of both compact bone(osteonal/osteon-like arrangements)and spongy bone(trabeculae separated by marrow cavities)reveal insights into function/need-driven microstructural *** within the CaP also contain both woven bone and vascularised lamellar *** actively contribute to CaP degradation/*** the constituent phases,only calcium pyrophosphate persists within osseous(cutting cones)and non-osseous(macrophages)*** a translational perspective,this multi-component CaP opens up exciting new avenues for osteotomy-free and minimally-invasive repair of large bone defects and augmentation of the dental alveolar ridge.

关键词： Bone Calcium phosphate Monetite Calcium pyrophosphate Electron microscopy Raman spectroscopy

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Magnesium implant degradation provides immunomodulatory and proangiogenic effects and attenuates peri-implant fibrosis in soft tissues

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Bioactive Materials 2023年第8期26卷 353-369页

作者： Heithem Ben Amara Diana C.Martinez Furqan A.Shah Anna Johansson Loo Lena Emanuelsson Birgitta Norlindh Regine Willumeit-Römer Tomasz Plocinski Wojciech Swieszkowski Anders Palmquist Omar Omar peter Thomsen Department of Biomaterials Institute of Clinical SciencesSahlgrenska AcademyUniversity of GothenburgGothenburgSweden Biomaterials Group Materials Design DivisionFaculty of Materials Science and EngineeringWarsaw University of TechnologyWarsawPoland Institute of Metallic Biomaterials Helmholtz-Zentrum HereonGeesthachtGermany

Implants made of magnesium(Mg)are increasingly employed in patients to achieve osteosynthesis while degrading in *** Mg implants and Mg^(2+)have been suggested to possess anti-inflammatory properties,the clinically observed soft tissue inflammation around Mg implants is ***,using a rat soft tissue model and a 1-28 d observation period,we determined the temporo-spatial cell distribution and behavior in relation to sequential changes of pure Mg implant surface properties and Mg^(2+)*** to nondegradable titanium(Ti)implants,Mg degradation exacerbated initial *** of Mg degradation products at the tissue-implant interface,culminating at 3 d,actively initiated chemotaxis and upregulated mRNA and protein immunomodulatory markers,particularly inducible nitric oxide synthase and toll-like receptor-4 up to 6 d,yet without a cytotoxic *** vascularization was demonstrated morphologically,preceded by high expression of vascular endothelial growth *** transition to appropriate tissue repair coincided with implant surface enrichment of Ca and P and reduced peri-implant Mg^(2+)*** implants revealed a thinner fibrous encapsulation compared with *** detailed understanding of the relationship between Mg material properties and the spatial and time-resolved cellular processes provides a basis for the interpretation of clinical observations and future tailoring of Mg implants.

关键词： Magnesium Biodegradable implants Inflammation Foreign-body reaction Gene expression Neovascularization

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NOTUM inhibition increases endocortical bone formation and bone strength

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Bone Research 2019年第1期7卷 54-65页

作者： Robert Brommage Jeff Liu peter Voge Faika Mseeh Andrea Y.Thompson David G.Potter Melanie K.Shadoan Gwenn M.Hansen Sabrina Jeter-Jones Jie Cui Dawn Bright Jennifer P.Bardenhagen Deon D.Doree Sofia Moverare-Skrtic Karin H.Nilsson Petra Henning Ulf H.Lerner Claes Ohlsson Arthur T.Sands James E.Tarver David R.Powell Brian Zambrowicz Qingyun Liu Lexicon Pharmaceuticals The WoodlandsTXUSA Wntrix HoustonTXUSA PRA Health Sciences RaleighNCUSA University of Pennsylvania PhiladelphiaPAUSA Regeneron Pharmaceuticals TarrytownNYUSA University of Texas HoustonTXUSA Centre for Bone and Arthritis Research Institute of MedicineThe Sahlgrenska Academy at University of GothenburgGothenburgSweden Centre for Bone and Arthritis Research University of GothenburgGothenburgSweden Biogen CambridgeMAUSA St.Jude Children’s Research Hospital MemphisTNUSA MD Anderson Cancer Center HoustonTXUSA Bethyl Laboratories MontgomeryTXUSA Merck RahwayNJUSA Nurix San FranciscoCAUSA

The disability,mortality and costs caused by non-vertebral osteoporotic fractures are *** osteoporosis therapies are highly effective at reducing vertebral but not non-vertebral *** bone is a major determinant of non-vertebral bone *** identify novel osteoporosis drug targets,we phenotyped cortical bone of 3 366 viable mouse strains with global knockouts of druggable *** bone thickness was substantially elevated in Notum?/?*** is a secreted WNT lipase and we observed high NOTUM expression in cortical bone and osteoblasts but not *** orally active small molecules and a neutralizing antibody inhibiting NOTUM lipase activity were *** increased cortical bone thickness and strength at multiple skeletal sites in both gonadal intact and ovariectomized rodents by stimulating endocortical bone ***,inhibition of NOTUM activity is a potential novel anabolic therapy for strengthening cortical bone and preventing non-vertebral fractures.

关键词： disability osteoporosis fractures

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