Download or read book Petcoil written by Qian Dong and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Simultaneous positron emission tomography/magnetic resonance imaging (PET/MRI) has shown promise in acquiring complementary multiparametric information of diseases. However, designing these hybrid imaging systems is challenging due to the propensity for mutual interference between the PET and MRI sub-systems. In addition, the current high cost of permanently-integrated PET/MRI systems limits their long-term development and deployment, as well as patient accessibility. To overcome these limitations, we explored a brain-dedicated PET insert for an existing MRI system to achieve simultaneous PET/MRI. Because of its brain-dedicated design, this insert also provides superior spatial resolution and sensitivity compared to whole-body scanners. The second-generation prototype builds upon the success of the first-generation prototype, which demonstrated radio-frequency (RF)-penetrability and MR-compatibility. The new design includes additional features such as a longer axial field of view, time-of-flight (TOF) functionality, and improved portability, resulting in improved PET performance but presenting greater technical challenges for MR-compatibility. This thesis presents the development of the second-generation brain-dedicated PET insert for simultaneous PET/MRI. Our objective is to achieve high levels of both PET performance and MR-compatibility. The detailed design, architecture, experiment setup, results and analysis of the second-generation brain-dedicated PET insert are presented, highlighting the progress towards realizing a cost-efficient and effective simultaneous PET/MRI system for neurological imaging.

Download or read book Advances in organ specific PET instrumentation and their clinical and research applications An Issue of PET Clinics E Book written by Abass Alavi and published by Elsevier Health Sciences. This book was released on 2023-11-13 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this issue of PET Clinics, guest editors Drs. Abass Alavi, Habib Zaidi, and Suleman Surti bring their considerable expertise to the topic of Advances in Organ-specific PET Instrumentation and Their Clinical Applications. Top experts cover key topics such as the increasing use of silicon photomultiplier (SiPM) technology, advances in depth-of-interaction (DOI) and time-of-flight (TOF) PET detectors, the use of artificial intelligence technologies for detector development; and more. Contains 11 relevant, practice-oriented topics including advances in PET detectors and readout technologies; whole-gamma imaging; clinical applications of dedicated brain PET; clinical applications of dedicated breast PET; potential clinical applications of dedicated prostate PET; and more. Provides in-depth clinical reviews on advances in organ-specific PET instrumentation and their clinical applications, offering actionable insights for clinical practice. Presents the latest information on this timely, focused topic under the leadership of experienced editors in the field. Authors synthesize and distill the latest research and practice guidelines to create clinically significant, topic-based reviews.

Download or read book Hybrid MR PET Imaging written by N Jon Shah and published by Royal Society of Chemistry. This book was released on 2018-11-29 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combination of two leading imaging techniques – magnetic resonance imaging and positron emission tomography – is poised to have a large impact and has recently been a driver of research and clinical applications. The hybrid instrument is capable of acquiring both datasets simultaneously and this affords a number of advantages ranging from the obvious, two datasets acquired in the time required for one, through to novel applications. This book describes the basics of MRI and PET and then the technical issues and advantages involved in bringing together the two techniques. Novel applications in preclinical settings, human imaging and tracers are described. The book is for students and scientists entering the field of MR–PET with an MRI background but lacking PET or vice versa. It provides practical details from experts working in the area.

Download or read book Pharmacoproteomics written by Seth K. Amponsah and published by Springer Nature. This book was released on with total page 479 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Sage Handbook of Cognitive and Systems Neuroscience written by Gregory J. Boyle and published by SAGE Publications Limited. This book was released on 2023-11-08 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cognitive neuroscience is the interdisciplinary study of how cognitive and intellectual functions are processed and represented within the brain, which is critical to building understanding of core psychological and behavioural processes such as learning, memory, behaviour, perception, and consciousness. Understanding these processes not only offers relevant fundamental insights into brain-behavioural relations, but may also lead to actionable knowledge that can be applied in the clinical treatment of patients with various brain-related disabilities. This Handbook focusses on the foundational principles, methods, and underlying systems in cognitive and systems neuroscience, as well as examining cutting-edge methodological advances and innovations. Containing 34 original, state of the art contributions from leading experts in the field, this Handbook is essential reading for researchers and students of cognitive psychology, as well as scholars across the fields of neuroscientific, behavioural and health sciences. Part 1: Background Considerations Part 2: Neuroscientific Substrates and Principles Part 3: Neuroanatomical Brain Systems Part 4: Neural Dynamics and Processes Part 5: Sensory-Perceptual Systems and Cognition Part 6: Methodological Advances

Download or read book From linear to long chain branched poly ethylene terephthalate reactive extrusion rheology and molecular characterization written by Kruse, Matthias and published by Universitätsverlag der TU Berlin. This book was released on 2017-07-11 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Poly(ethylene terephthalate) is one of the most widely used polymers in packaging industry, due to its high mechanical strength, chemical resistance, and barrier functions. However, its processing is determined by degradation and low viscosity. In particular, foaming and film blowing is restricted by the linear structure of the molecule and low melt strength. The stability of three linear commercial PET grades produced by different synthesis routes with different molar masses is analyzed in regards of processing at industrial scale. Subsequently, reactive processing with three multi-functional chain extenders (pyromellitic dianhydride, PMDA, tetraglycidyl diamino diphenyl methane, TGDDM, and triphenyl phosphite, TPP) is conducted to create large and long-chain branched (LCB) molecules. The mechanical and molecular properties in melt state are analyzed by linear and non-linear viscoelastic rheology, modeling by the molecular stress function (MSF) theory and size-exclusion chromatography (SEC) with light scattering measurements. Thermal stability measurements in the linear viscoelastic regime revealed degradation and a reduction of the storage modulus in air atmosphere, and, besides thermal degradation, an enhancement of the modulus in nitrogen atmosphere, due to polycondensation [Kruse et al., 2013]. Fitting by an exponential function leads to the reconstruction of the initial state of the sample at zero-loading time and to a time constant, which reveals clear relations between stability and molar mass for all three PET grades in both atmospheres. High molar mass PET is more stable in nitrogen and less stable in air environment, and vice versa, depending on OH end group concentration and synthesis route. The analysis by means of time-resolved mechanical spectroscopy allows the observations of moduli and complex viscosity at a fixed time, a wide range of angular frequencies, and at different atmospheres, and revealed: (i) a plasticizer effect induced by small molecules from thermal and thermo-oxidative degradation, (ii) cross-linking leading to yield stress, (iii) diffusion influencing polycondensation reaction, (iv) slipping due to deposition of side products, and (v) an enhanced shear thinning regime [Kruse and Wagner, 2016]. The extrusion of neat PET with a twin-screw extruder at industrial scale leads to strong reduction of viscosity mainly due to shearing. The impact of thermo-oxidative degradation is comparably small. The reactive processing of the three PET grades with the three chain extenders leads to the conclusion that the tri-functional TPP is not a useful chain extender due to rapid degradation and toxicity. The two tetra-functional chain extenders, PMDA and the epoxy-based TGDDM, lead to strong viscosity increase, increasing strain hardening effect, and increasing thermal stability with increasing chain extender concentration as confirmed by loss- and storage modulus, phase angle, activation energy of flow, and elongational viscosity. The MSF model predictions show good agreement with data measured, and allowed a quantitative analysis of the branching structure and of the stretch of the molecules by both non-linear MSF parameters. In comparison to the high molar mass PET with an apparent comb-like structure at high PMDA concentrations, the two initially low molar mass grades show a higher molar mass after processing with PMDA and seem to have a tree-like structure, which can be explained by the hydroxyl end group concentration of these two PET grades. The extensive use of TGDDM leads to a hyperbranched and gel-like structure. The fracture analysis from uniaxial elongation experiments reveals a limiting stress value for high PMDA concentrations and a limiting strain value for high TGDDM concentrations due to formation of a covalent network. The molecular analysis by SEC with triple detection of the high molar mass PET, which was reacted with PMDA and TGDDM, shows a strong increase of the average molar masses, polydispersity, radius of gyration, and hydrodynamic radius and confirms the molar mass increase observed by the rheological measurements. The branching was confirmed by a decreasing Mark-Houwink exponent with increasing chain extender concentration. Further, the analysis of the contraction of the molecule revealed a more star-like structure at low concentrations for both chain extenders. With increasing concentration, the structure changed to more comb-like for PMDA and random tree-like or hyperbranched for TGDDM as was also observed by non-linear viscoelastic measurements. PMDA revealed to be an excellent coupling agent which induces reproducibly either a star-like, comb-like, or tree-like structures depending on the concentration of coupling agent added and the hydroxyl concentration of the PET employed. Polyethylenterephthalat (PET) zeichnet sich durch hervorragende mechanische Eigenschaften, sowie chemische Beständigkeit und Barriereeigenschaften aus und findet insbesondere in der Verpackungsindustrie Verwendung. Die Neigung zur Degradation und die wegen der linearen Kettenmoleküle geringe Viskosität schränken jedoch die Verarbeitbarkeit von PET wie beispielsweise das Schäumen und Folienblasen erheblich ein. In der vorliegenden Arbeit wird der Einfluss der thermischen Stabilität während der Verarbeitung von drei linearen industriellen PET-Typen untersucht, die sich durch Molmasse und Herstellungsverfahren unterscheiden. Des Weiteren wird langkettenverzweigtes PET (LCBPET) durch reaktive Verarbeitung mit drei verschiedenen multifunktionalen Kettenverlängerern, Pyromellitsäuredianhydrid (PMDA), Tetra- glycidyl-Diamino-Diphenyl-Methan (TGDDM) und Triphenylphosphit (TPP), hergestellt und charakterisiert. Durch die experimentelle Bestimmung der linearen und nichtlinearen rheologischen Eigenschaften der Schmelze und ihre Beschreibung mit Hilfe des sogenannten "Molecular Stress Function" (MSF) Modells gelingt eine quantitative Analyse des Materialverhaltens. Die molekulare Analyse wird zusätzlich durch die Ergebnisse von Gelpermeationschromatographie (GPC bzw. SEC) in Verbindung mit Lichtstreumessung gestützt. Die Untersuchungen der thermischen Stabilität von linearem PET im linear-viskoelastischen Bereich zeigen einen abnehmenden Speichermodul und somit ein thermo-oxidatives Degradationsverhalten in Luftatmosphäre. In inerter Stickstoffatmosphäre tritt hingegen nur thermische Degradation auf, gleichzeitig führt jedoch eine Polykondensationsreaktion zu einem Anstiegen des Moduls [Kruse et al., 2013]. Mit einem exponentiellen Regressionsansatz kann der anfängliche Zustand des Moduls in beiden Atmosphären zum Zeitpunkt Null, der dem Einbringen der Probe in das Rheometer entspricht, rekonstruiert werden. Die sich aus diesem Ansatz ergebende Zeitkonstante erlaubt es, quantitative Zusammenhänge zwischen der thermischen Stabilität der drei PET-Sorten und deren Molmasse sowie dem Herstellungsverfahren der PET-Typen aufzuzeigen. So weist hochmolekulares PET eine höhere Stabilität in Stickstoff und eine geringere Stabilität in Luft auf und umgekehrt. Hauptursache für dieses Verhalten ist die unterschiedliche Konzentration an Hydroxylendgruppen, die je nach Molmasse und Herstellungsmethode der jeweiligen PET-Typen variiert. Mit Hilfe der "Time-Resolved Mechnical Sprectroscopy" konnte die sich ändernde Viskosität über ein weites Frequenzspektrum und zu einer beliebigen Messzeit in beiden Atmosphären bestimmt werden. Wesentliche Ergebnisse dieser Untersuchung sind der Nachweis des Auftretens von (i) einem Weichmachereffekt bedingt durch die thermische und thermo-oxidative Degradation und den daraus resultierenden Oligomeren, (ii) dreidimensionaler Vernetzung mit der Ausbildung einer Fließgrenze, (iii) Diffusionsprozessen, die Einfluss auf die Polykondensationsreaktion haben, (iv) Wandgleiten, bedingt durch die Ablagerung von Nebenprodukten auf den Platten des Rheometers und (v) einem verbreiterten Scherverdünnungbereich [Kruse and Wagner, 2016]. Die Extrusion von linearem PET mit einem Doppelschneckenextruder unter industriellen Bedingungen führt zu einer starken Abnahme der Viskosität, die hauptsächlich durch Scherung und weniger durch thermo-oxidativen Abbau verursacht wird. Bei der reaktiven Verarbeitung der drei PET-Typen mit den drei verschiedenen Kettenverlängerern erwies sich das dreifunktionale TPP auf Grund von Toxizität und Lagerinstabilitäten als unbrauchbar. Die Verarbeitung der beiden vierfunktionalen Kettenverlängerer, PMDA und das epoxidhaltige TGDDM, führt zu erhöhter Viskosität, erhöhter Dehnverfestigung und erhöhter thermischer Stabilität mit zunehmender Konzentration des jeweiligen Kettenverlängerers. Das beschriebene Verhalten zeigt sich sowohl am Speicher- und Verlustmodul und dem daraus abgeleiteten Verlustwinkel, als auch an der Fließaktivierungsenergie und der Dehnviskosität. Dabei lassen sich die gemessenen Dehnviskositäten sehr präzise mit dem MSF-Modell beschreiben und die beiden nichtlinearen Modelparameter, β und f_max^2 ermöglichen eine quantitative Analyse der Verzweigungsstruktur und der Molekülstreckung. So zeigt die Modifiziereng von hohen PMDA-Konzentrationen und dem hochmolekularen PET eine mehr kammartige Struktur im Vergleich zu den beiden niedermolekularen PET-Typen, die eine baumartige Molekülstruktur und eine höhere Molmasse nach der reaktiven Extrusion aufweisen. Beide Effekte können mit der höheren OH-Endgruppenkonzentration der beiden niedermolekularen PET-Typen erklärt werden. Zu hohe Zusätze von TGDDM führen zu einem hochverzweigten und gelartigen Polymer. Das Bruchverhalten bei der uniaxialen Dehnung von mit einem hohen Zusatz von PMDA hergestellten langkettenverzweigten PET wird von einer limitierenden Bruchspannung bestimmt. Demgegenüber bestimmt eine maximale Dehnung das Bruchverhalten des mit einem hohen TGDDM-Zusatz hergestellten LCB-PET, verursacht durch ein kovalent gebundenes Polymernetzwerk. Die GPC Messungen mit drei Detektoren wurden an LCB-PET durchgeführt, das auf Basis der hochmolekularen PET-Type hergestellt wurde. Die molekulare Analyse der mit PMDA und TGDDM modifizierten Proben zeigt eine deutliche Zunahme der mittleren Molmassen, Molmassenverteilungsbreite, des Gyrationsradius und des hydrodynamischen Radius und bestätigt somit die rheologischen Ergebnisse. Das Auftreten von Verzweigungen wird außerdem durch den abnehmenden Mark-Houwink-Exponenten bei zunehmender Additivkonzentration verdeutlicht. Eine genauere Betrachtung weist auf eine sternartige Molekülstruktur bei geringer Zugabe beider Kettenverlängerer hin. Bei erhöhter Zugabe hingegen tritt eine kammartige Struktur bei PMDA und eine baumartige oder hochverzweigte Struktur bei TGDDM auf, wie auch aus den nichtlinearen viskoelastischen Messungen zu schließen ist. Insbesondere PMDA erweist sich als hervorragender Kettenverlängerer, der bei reaktiver Extrusion reproduzierbar eine sternartige, kammartige oder baumartige Molekülstruktur in Abhängigkeit von der verwendeten PET-Type und der PMDA-Konzentration ermöglicht und so das Verarbeitungsspektrum von PET auf neue Anwendungsgebiete erweitert.

Download or read book The Office of Industrial Technologies Technical Reports written by and published by . This book was released on 1992 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Register of Commissioned and Warrant Officers of the United States Navy and Marine Corps and Reserve Officers on Active Duty written by United States. Bureau of Naval Personnel and published by . This book was released on 1959 with total page 1282 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy Research Abstracts written by and published by . This book was released on 1985 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Oxford Handbook of Transcranial Stimulation written by and published by Oxford University Press. This book was released on 2024-08-14 with total page 1249 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transcranial stimulation encompasses noninvasive methods that transmit physical fields-such as magnetic, electric, ultrasound, and light-to the brain to modulate its function. The most widespread approach, transcranial magnetic stimulation (TMS), has emerged as an important tool in several areas of neuroscience as well as in clinical applications in psychiatry and neurology. Originally envisioned as a way to measure the responsiveness and conduction speed of neurons and synapses in the brain and spinal cord, TMS has also become an important tool for changing the activity of brain neurons and the functions they subserve as well as an causal adjunct to brain imaging and mapping techniques. Along with transcranial electrical stimulation techniques, TMS has diffused far beyond the borders of clinical neurophysiology and into cognitive, perceptual, behavioural, and therapeutic investigation and attracted a highly diverse group of users and would-be users. Another major success of TMS has been as a treatment in psychiatry, where it is now in routine use worldwide. The field of noninvasive neuromodulation has matured and diversified considerably in the past decade, with an expansion in the number of tools available and our understanding of their mechanisms of action. This second edition of The Oxford Handbook of Transcranial Stimulation brings together the latest developments and important advances in all areas of Transcranial stimulation. The new volume captures the rapid progress made since the first edition, and provides an authoritative and comprehensive review of the state of the art. It also highlights challenges, opportunities, and future directions for this rapidly changing field. The book focuses on the scientific and technical background required to understand transcranial stimulation techniques and a wide-ranging survey of their burgeoning applications in neurophysiology, neuroscience, and therapy. Each of its six sections deals with a major area and is edited by an international authority therein. It will serve researchers, clinicians, students, and others as the definitive text in this area for years to come.

Download or read book Labor Market Information written by and published by . This book was released on 1946 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1986 with total page 1338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Imaging in Neurodegenerative Disorders written by Luca Saba and published by Oxford University Press, USA. This book was released on 2015 with total page 585 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text summarizes the latest developments in imaging techniques and other new diagnostic methods as applied to the neurodegenerative disorders.

Download or read book Crockford s Clerical Directory written by and published by . This book was released on 1918 with total page 2338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Gas Review written by and published by . This book was released on 1910 with total page 1050 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Monthly Packet written by and published by . This book was released on 1864 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Official Summary of Security Transactions and Holdings Reported to the Securities and Exchange Commission Under the Securities Exchange Act of 1934 and the Public Utility Holding Company Act of 1935 written by and published by . This book was released on with total page 904 pages. Available in PDF, EPUB and Kindle. Book excerpt: