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Targeted heat treatment of additively manufactured Ti-6Al-4v for controlled formation of Bi-lamellar microstructures

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Journal of Materials Science & Technology 2021年第22期81卷 67-76页

作者： cecilie v.funch Alessandro Palmas Kinga Somlo Emilie H.valente Xiaowei Cheng Konstantinos Poulios Matteo villa Marcel A.J.Somers Thomas L.Christiansena Department of Mechanical Engineering Technical University of DenmarkProduktionstorvetBuilding 4252800 Kongens LyngbyDenmark College of Materials Science and Engineering Chongqing UniversityChongqing 400044China

Laser powder bed fusion(L-PBF)was utilized to produce specimens in Ti-6Al-4v,which were subjected to a bi-lamellar heat treatment,which produces microstructures consisting of primary α-lamellae and a fine secondary α-phase inside the inter-lamellar β-*** bi-lamellar microstructure was obtained as(i)a direct bi-lamellar heat treatment from the asbuilt condition or(ii)a bi-lamellar heat treatment preceded by a β-*** the bi-lamellar treatment with β-homogenization,cooling rates in the range 1-500 K/min were applied after homogenization in β-region followed by inter-critical annealing in the α+β region at various temperatures in the range 850-950℃.The microstructures were characterized using various microscopical *** testing with vickers hardness indentation and tensile testing was *** bi-lamellar microstructure was harder when compared to a soft fully lamellar microstructure,because of the presence of fine α-platelets inside the β-*** low temperature ageing provided an additional hardness increase by precipitation hardening of the primary α-*** age hardened bi-lamellar microstructure shows a similar hardness as the very fine,as-built martensitic *** bi-lamellar microstructure has more favorable mechanical properties than the as-built condition,which has high strength,but poor *** the bi-lamellar heat treatment,the elongation was improved by more than 250%.Due to the very high strength of the as-built condition,loss of tensile strength is unavoidable,resulting in a reduction of tensile strength of~18%.

关键词： Additive manufacturing Ti-6Al-4v Targeted heat treatment Bi-lamellar microstructures Laser powder bed fusion

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Evaluation of the biliary tract in patients with functional biliary symptoms

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World Journal of Gastroenterology 2006年第18期12卷 2839-2845页

作者： Peter funch-Jensen Asbjφrn Mohr Drewes László Madácsy Surgical Gastroenterological Department L Aarhus University HospitalAarhusDenmark Center for visceral Biomechanics and Pain Department of GastroenterologyAalborg Sygehus and Center of Sensory Motor Interaction (SMI)University of AalborgDenmark First Department of Internal Medicine and OMCH Endoscopy Unit Fejér Megyei Szent Gyrgy HospitalSzékesfehérvárHungary

The aim of this paper was to describe functional biliary syndromes and methods for evaluation of the biliary tract in these patients. Functional biliary symptoms can be defined as biliary symptoms without demonstrable organic substrate. Two main syndromes exist： Gallbladder dysfunction and sphincter of Oddi dysfunction. The most important investigative tools are cholescintigraphy and endoscopic sphincter of Oddi manometry. In gallbladder dysfunction a scintigraphic gallbladder ejection fraction below 35% can select patients who will benefit from cholecystectomy. Endoscopic sphincter of Oddi manometry is considered the gold standard in sphincter of Oddi dysfunction but recent development in scintigraphic methods is about to change this. Thus, calculation of hilum-to-duodenum transit time and duodenal appearance time on cholescintigraphy have proven useful in these patients. In conclusion, ambient methods can diagnose functional biliary syndromes. However, there are still a number of issues where further knowledge is needed. Probably the next step forward will be in the area of sensory testing and impedance planimetric methods.

关键词： Functional biliary pain Scintigraphy Manometry Pain Sphincter of Oddi Gallbladder

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Experimental human pain models in gastro-esophageal reflux disease and unexplained chest pain

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World Journal of Gastroenterology 2006年第18期12卷 2805-2817页

作者： Asbjφrn Mohr Drewes Lars Arendt-Nielsen Peter funch-Jensen Hans Gregersen Center for visceral Biomechanics and Pain Department of GastroenterologyAalborg Hospitaland Center for Sensory-Motor InteractionsDepartment of Health Science and TechnologyAalborg UniversityDenmark Department of Surgical Gastroenterology L Aarhus HospitalDenmark

Methods related to experimental human pain research aim at activating different nociceptors, evoke pain from different organs and activate specific pathways and mechanisms. The different possibilities for using mechanical, electrical, thermal and chemical methods in visceral pain research are discussed with emphasis of combinations (e.g., the multimodal approach). The methods have been used widely in assessment of pain mechanisms in the esophagus and have contributed to our understanding of the symptoms reported in these patients. Hence abnormal activation and plastic changes of central pain pathways seem to play a major role in the symptoms in some patients with gastro-esophageal reflux disease and in patients with functional chest pain of esophageal origin. These findings may lead to an alternative approach for treatment in patients that does not respond to conventional medical or surgical therapy.

关键词： Pain Gut Experimental Chest pain Esophagitis

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Reversibility of central neuronal changes in patients recovering from gallbladder stones or acute cholecystitis

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World Journal of Gastroenterology 2006年第46期12卷 7522-7526页

作者： Daniel W Kjaer Marek Stawowy Lars Arendt-Nielsen Asbjφrn Mohr Drewes Peter funch-Jensen Surgical Gastroenterology Department L Aarhus University Hospital Aarhus Denmark Department of Hepato-Gastroenterology v Aarhus University Hospital Aarhus Denmark Center for Sensory-Motor Interactions Department of Health Science and Technology Aalborg University Denmark Department of Medical Gastroenterology Aalborg University Hospital Aalborg Denmark

AIM: To investigate the referred pain area in patients 2-7 years after cholecystectomy in order to test the hypothesis that neuroplastic changes could give rise to post cholecystectomy pain. METHODS: Forty patients were tested. Twenty five were cholecystectomized due to uncomplicated gallbladder stones and 15 because of acute cholecystitis. Sensitivity to pinprick, heat, cold, pressure and single and repeated electrical stimulation was studied both in the referred pain area and in the control area on the contra lateral side of the abdomen. RESULTS: Five patients still intermittently suffered from pain. But in the objective test of the 40 patients, no statistical significant difference was found between the referred pain area and the control area. CONCLUSION: This study does not support the hypothesis that de novo neuroplastic changes could develop several years after cholecys-tectomy.

关键词： Referred pain Hyperalgesia Cholecystitis Post cholecystectomy syndrome

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Proximal and distal esophageal sensitivity is decreased in patients with Barrett’s esophagus

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World Journal of Gastroenterology 2011年第4期17卷 514-521页

作者： Anne L Kraru Sφren S Olesen Peter funch-Jensen Hans Gregersen Asbjφrn M Drewes Mech-Sense Department of Gastroenterology Aalborg Hospital Aarhus University Hospital Department of Surgery L Aarhus University Hospital

AIM: To investigate sensations to multimodal pain stimulation in the metaplastic and normal parts of the esophagus in patients with Barrett’s esophagus (BE). METHODS: Fifteen patients with BE and 15 age-matched healthy volunteers were subjected to mechanical, thermal and electrical pain stimuli of the esophagus. Both the metaplastic part and the normal part (4 and 14 cm, respectively, above the esophago-gastric junction) were examined. At sensory thresholds the stimulation intensity, referred pain areas, and evoked brain potentials were recorded. RESULTS: Patients were hyposensitive to heat stimulation both in the metaplastic part [median stimulation time to reach the pain detection threshold: 15 (12-34) s vs 14 (6-23) s in controls; F = 4.5, P = 0.04] and the normal part of the esophagus [median 17 (6-32) s vs 13 (8-20) s in controls; F = 6.2, P = 0.02]. Furthermore, patients were hyposensitive in the metaplastic part of the esophagus to mechanical distension [median volume at moderate pain: 50 (20-50) mL vs 33 (13-50) mL in controls; F = 5.7, P = 0.02]. No indication of central nervous system abnormalities was present, as responses were comparable between groups to electrical pain stimuli in the metaplastic part [median current evoking moderate pain: 13 (6-26) mA vs 12 (9-24) mA in controls; F = 0.1, P = 0.7], and in the normal part of the esophagus [median current evoking moderate pain: 9 (6-16) mA, vs 11 (5-11) mA in controls; F = 3.4, P = 0.07]. Furthermore, no differences were seen for the referred pain areas (P-values all > 0.3) or latencies and amplitudes for the evoked brain potentials (P-values all > 0.1). CONCLUSION: Patients with BE are hyposensitive both in the metaplastic and normal part of esophagus likely as a result of abnormalities affecting peripheral nerve pathways.

关键词： Barrett’s esophagus Heat Multimodal Pain Sensitivity

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Sensory-motor responses to mechanical stimulation of the esophagus after sensitization with acid

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World Journal of Gastroenterology 2005年第28期11卷 4367-4374页

作者： Asbjφrn Mohr Drewes Hariprasad Reddy Camilla Staahl Jan Pedersen Peter funch-Jensen Lars Arendt-Nielsen Hans Gregersen Center for Biomechanics and Pain Department of Gastroenterology Aalborg HospitalAarhus University HospitalAalborgDenmark Department of Surgical Gastroenterology L Aarhus University Hospital AarhusDenmark Center for Sensory-Motor Interactions (SMI) Department of Health Science and Technology Aalborg UniversityAalborgDenmark

AIM: Sensitization most likely plays an important role in chronic pain disorders, and such sensitization can be mimicked by experimental acid perfusion of the *** current study systematically investigated the sensory and motor responses of the esophagus to controlled mechanical stimuli before and after ***: Thirty healthy subjects were *** of the distal esophagus with a balloon was performed before and after perfusion with 0.1 mol/L hydrochloric acid for 30 min. An impedance planimetry system was used to measure cross-sectional area,volume, pressure, and tension during the distensions. A new model allowed evaluation of the phasic contractions by the tension during contractions as a function of the initial muscle length before the contraction (comparable to the Frank-Starling law for the heart). Length-tension diagrams were used to evaluate the muscle tone before and after relaxation of the smooth muscle with ***: The sensitization resulted in allodynia and hyperalgesia to the distension volumes, and the degree of sensitization was related to the infused volume of acid. Furthermore, a nearly 50% increase in the evoked referred pain was seen after sensitization. The mechanical analysis demonstrated hyper-reactivity of the esophagus following acid perfusion, with an increased number and force of the phasic contractions, but the muscle tone did not ***: Acid perfusion of the esophagus sensitizes the sensory pathways and facilitates secondary *** new model can be used to study abnormal sensorymotor mechanisms in visceral organs.

关键词： Esophagus Mechanical Sensitization Motility Reflux Pain

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Impaired contractility and remodeling of the upper gastrointestinal tract in diabetes mellitus type-1

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World Journal of Gastroenterology 2007年第36期13卷 4881-4890页

作者： Jens BrΦndum FrΦkjΦr SΦren Due Andersen Niels EjskjΦr Peter funch-Jensen AsbjΦrn Mohr Drewes Hans Gregersen Center for visceral Biomechanics and Pain Aalborg Hospital Aalborg Denmark Department of Radiology Aalborg Hospital Aalborg Denmark Department of Endocrinology M Aarhus University Hospital Aarhus Denmark Department of Surgical Gastroenterology L Aarhus University Hospital Aarhus Denmark Center for Sensory-Motor Interaction Department of Health Science and Technology Aalborg University Denmark Center for Sensory-Motor Interaction Department of Health Science and Technology Aalborg University Denmark National Center for Ultrasound in Gastro-enterology Haukeland University Hospital Bergen Norway

AIM: To investigate that both the neuronal function of the contractile system and structural apparatus of the gastrointestinal tract are affected in patients with longstanding diabetes and auto mic neuropathy. METHODS: The evoked esophageal and duodenal contractile activity to standardized bag distension was assessed using a specialized ultrasound-based probe. Twelve type-1 diabetic patients with autonomic neuropathy and severe gastrointestinal symptoms and 12 healthy controls were studied. The geometry and biomechanical parameters (strain, tension/stress, and stiffness) were assessed. RESULTS: The diabetic patients had increased frequency of distension-induced contractions (6.0 ± 0.6 vs 3.3 ± 0.5, P vity was correlated with the duration of the disease (P = 0.009). Impaired coordination of the contractile activity in diabetic patients was demonstrated as imbalance between the time required to evoke the first contraction at the distension site and proximal to it (1.5 ± 0.6 vs 0.5 ± 0.1, P = 0.03). The esophageal wall and especially the mucosa-submucosa layer had increased thickness in the patients (P ve stretch was less in diabetics (P 0.14). CONCLUSION: The impaired contractile activity with an imbalance in the distension-induced contractions likely reflects neuronal abnormalities due to autonomic neuropathy. However, structural changes and remodeling of the gastrointestinal tract are also evident and may add to the neuronal changes. This may contribute to the pathophysiology of diabetic gut dysfunction and impact on future management of diabetic patients with gastrointestinal symptoms.

关键词： Diabetes Autonomic Neuropathy Bio- mechanics Contractility Ultrasound Esophagus Duodenum Deformation Stress

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Pressure pain sensitivity: A new stress measure in children and adolescents with type 1 diabetes?

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World Journal of Clinical Pediatrics 2024年第1期13卷 150-154页

作者： Annemarie cecilie Grauslund Emilie Bundgaard Lindkvist Steffen Ullitz Thorsen Søren Ballegaard Jens Faber Jannet Svensson Anna Korsgaard Berg Department of Pediatrics Herlev and Gentofte HospitalHerlev 2730Denmark Copenhagen University Hospital Steno Diabetes Center CopenhagenHerlev 2730Denmark Department of Clinical Immunology RigshospitaletUniversity of CopenhagenCopenhagen 2100Denmark Department of Endocrinology Herlev and Gentofte HospitalHerlev 2730Denmark Department of Clinical Medicine Faculty of Health and Medical SciencesUniversity of CopenhagenCopenhagen 2200Denmark

Type 1 diabetes(T1D)is associated with general-and diabetes-specific stress which has multiple adverse *** measuring stress is of great *** algometer measuring pressure pain sensitivity(PPS)has been shown to correlate to certain stress measures in ***,it has never been investigated in children and *** aim of our study was to examine associations between PPS and glycated hemoglobin(HbA1c),salivary cortisol and two questionnaires as well as to identify whether the algometer can be used as a clinical tool among children and adolescents with ***-three participants aged 6-18 years and diagnosed with T1D were included in this study with data from two study *** cortisol,PPS and questionnaires were collected,measured,and answered on ***1c was collected from medical *** found correlations between PPS and HbA1c(rho=0.35,P=0.046),cortisol(rho=-0.25,P=0.02)and Perceived Stress Scale(rho=-0.44,P=0.02)in different subgroups based on *** scored higher in PPS than females(Pvalues indicated either measurement difficulties or hypersensibility towards pain.

关键词： Stress Children and adolescents Type 1 diabetes Autonomic dysfunction

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