Página 1 dos resultados de 740 itens digitais encontrados em 0.024 segundos

‣ Invited Review Article: Imaging techniques for harmonic and multiphoton absorption fluorescence microscopy

Carriles, Ramón; Schafer, Dawn N.; Sheetz, Kraig E.; Field, Jeffrey J.; Cisek, Richard; Barzda, Virginijus; Sylvester, Anne W.; Squier, Jeffrey A.
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artigo de Revista Científica
Português
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We review the current state of multiphoton microscopy. In particular, the requirements and limitations associated with high-speed multiphoton imaging are considered. A description of the different scanning technologies such as line scan, multifoci approaches, multidepth microscopy, and novel detection techniques is given. The main nonlinear optical contrast mechanisms employed in microscopy are reviewed, namely, multiphoton excitation fluorescence, second harmonic generation, and third harmonic generation. Techniques for optimizing these nonlinear mechanisms through a careful measurement of the spatial and temporal characteristics of the focal volume are discussed, and a brief summary of photobleaching effects is provided. Finally, we consider three new applications of multiphoton microscopy: nonlinear imaging in microfluidics as applied to chemical analysis and the use of two-photon absorption and self-phase modulation as contrast mechanisms applied to imaging problems in the medical sciences.

‣ Invited Review Article: Review of centrifugal microfluidic and bio-optical disks

Nolte, David D.
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Artigo de Revista Científica
Português
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Spinning biodisks have advantages that make them attractive for specialized biochip applications. The two main classes of spinning biodisks are microfluidic disks and bio-optical compact disks (BioCD). Microfluidic biodisks take advantage of noninertial pumping for lab-on-a-chip devices using noninertial valves and switches under centrifugal and Coriolis forces to distribute fluids about the disks. BioCDs use spinning-disk interferometry, under the condition of common-path phase quadrature, to perform interferometric label-free detection of molecular recognition and binding. The optical detection of bound molecules on a disk is facilitated by rapid spinning that enables high-speed repetitive sampling to eliminate 1∕f noise through common-mode rejection of intensity fluctuations and extensive signal averaging. Multiple quadrature classes have been developed, such as microdiffraction, in-line, phase contrast, and holographic adaptive optics. Thin molecular films are detected through the surface dipole density with a surface height sensitivity for the detection of protein spots that is approximately 1 pm. This sensitivity easily resolves a submonolayer of solid-support immobilized antibodies and their antigen targets. Fluorescence and light scattering provide additional optical detection techniques on spinning disks. Immunoassays have been applied to haptoglobin using protein A∕G immobilization of antibodies and to prostate specific antigen. Small protein spots enable scalability to many spots per disk for high-throughput and highly multiplexed immonoassays.

‣ Electrosurgery in aesthetic and restorative dentistry: A literature review and case reports

Bashetty, Kusum; Nadig, Gururaj; Kapoor, Sandhya
Fonte: Medknow Publications Publicador: Medknow Publications
Tipo: Artigo de Revista Científica
Publicado em //2009 Português
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Electrosurgery has been used in dentistry for more than half a century. There is abundant literature on electrosurgery dating back more than a century. During the past three decades, a substantial increase in minimally invasive surgery and microvascular surgery prompted greater use of electrosurgery. Although this surge in utilization has resulted in new applications, equipment features, problems and solutions, the use of electrosurgery in the field of restorative dentistry has remained relatively unchanged. The presence of conflicting and sometimes confusing information on electrosurgical wound healing in the dental literature is the most likely reason. This article briefly explains the literature review of electrosurgery and clinical application of electrosurgery in aesthetic and restorative dentistry.

‣ Indirect resin composites

Nandini, Suresh
Fonte: Medknow Publications Publicador: Medknow Publications
Tipo: Artigo de Revista Científica
Publicado em //2010 Português
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Aesthetic dentistry continues to evolve through innovations in bonding agents, restorative materials, and conservative preparation techniques. The use of direct composite restoration in posterior teeth is limited to relatively small cavities due to polymerization stresses. Indirect composites offer an esthetic alternative to ceramics for posterior teeth. This review article focuses on the material aspect of the newer generation of composites. This review was based on a PubMed database search which we limited to peer-reviewed articles in English that were published between 1990 and 2010 in dental journals. The key words used were ‘indirect resin composites,’ composite inlays,’ and ‘fiber-reinforced composites.’

‣ Centenary celebrations article: Cysteine proteases of human malaria parasites

Pandey, Kailash C.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Português
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There is an urgent need for new drugs against malaria, which takes millions of lives annually. Cysteine proteases are potential new drug targets, especially when current drugs are showing resistance. Falcipains and vivapains are well characterized cysteine proteases of P. falciparum and P. vivax, respectively. Studies with cysteine protease inhibitors and manipulating cysteine proteases specific genes have suggested their roles in hemoglobin hydrolysis. In P. falciparum, falcipain-2 and falcipain-3 are major hemoglobinases that hydrolyze host erythrocyte hemoglobin in the parasite food vacuole. It is confirmed that disruption of the falcipain-2 gene led to a transient block in hemoglobin hydrolysis, and disruption of falcipain-3 gene was not possible, suggesting that protease is essential for erythrocytic parasites. On the other hand, vivapain-2, vivapain-3 and vivapain-4 are important cysteine proteases of P. vivax, which shared a number of features with falcipain-2 and falcipain-3. A recent study indicates that vivapains and aspartic protease of P. vivax works collaboratively to enhance the parasites’ ability to hydrolyze host erythrocyte hemoglobin. Studies also indicate that falcipains and vivapains also hydrolyse the erythrocyte cytoskeleton proteins and involved in rupture of red blood cell. Structural and biochemical analysis of falcipains and vivapains showed that they have unique domains for specific functions. Overall...

‣ The younger sibling of PTSD: similarities and differences between complicated grief and posttraumatic stress disorder

Maercker, Andreas; Znoj, Hansjörg
Fonte: Co-Action Publishing Publicador: Co-Action Publishing
Tipo: Artigo de Revista Científica
Publicado em 06/12/2010 Português
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Just as traumatic experiences may lead to posttraumatic stress disorder (PTSD) in some individuals, grief may also be a serious health concern for individuals who have experienced bereavement. At present, neither the DSM-IV nor the ICD-10 recognizes any form of grief as a mental disorder. The aim of this review is to summarize recent advances in definition, assessment, prevention, and treatment of complicated grief disorder (CGD) and to compare CGD with PTSD. Four areas are identified to be of importance to clinicians and researchers: (a) the recently proposed consensus criteria of CGD for DSM-V and ICD-11, (b) available assessment instruments, (c) recent prevention and treatment techniques and related effectiveness studies, and (d) emerging disorder models and research on risks and protective factors. This review focuses on the similarities and differences between CGD and PTSD and highlights how a PTSD-related understanding aids the investigation and clinical management of CGD.

‣ Review of “orthopaedic biomechanics” edited by Beth A. Winkelstein

Samuel, Solomon P; Tiedeken, Nathan C
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 18/04/2013 Português
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This article is a review of the book “orthopaedic biomechanics” edited by Beth A. Winkelstein. This book (hardcover) was published by CRC Press, Taylor & Francis Group, FL in 2012. The contents of the book and its relevance to orthopedic research or practice is discussed in this invited review.

‣ Book review of “Joining and assembly of medical materials and devices” edited by Y. (Norman) Zhou and Mark D. Breyen

Samuel, Solomon P; Tiedeken, Nathan C
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 08/09/2013 Português
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This article is a review of the book “Joining and assembly of medical materials and devices” edited by Y. (Norman) Zhou and Mark D. Breyen. This book (hardcover) was published by Woodhead Publishing, Cambridge, UK in 2013. The contents of the book and its relevance to medical device design and education are discussed in this invited review.

‣ Invited Review Article: Methods for imaging weak-phase objects in electron microscopy

Glaeser, Robert M.
Fonte: AIP Publishing LLC Publicador: AIP Publishing LLC
Tipo: Artigo de Revista Científica
Português
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Contrast has traditionally been produced in electron-microscopy of weak phase objects by simply defocusing the objective lens. There now is renewed interest, however, in using devices that apply a uniform quarter-wave phase shift to the scattered electrons relative to the unscattered beam, or that generate in-focus image contrast in some other way. Renewed activity in making an electron-optical equivalent of the familiar “phase-contrast” light microscope is based in part on the improved possibilities that are now available for device microfabrication. There is also a better understanding that it is important to take full advantage of contrast that can be had at low spatial frequency when imaging large, macromolecular objects. In addition, a number of conceptually new phase-plate designs have been proposed, thus increasing the number of options that are available for development. The advantages, disadvantages, and current status of each of these options is now compared and contrasted. Experimental results that are, indeed, superior to what can be accomplished with defocus-based phase contrast have been obtained recently with two different designs of phase-contrast aperture. Nevertheless, extensive work also has shown that fabrication of such devices is inconsistent...

‣ Invited Review: The Myosins: Exploration of the Development of Our Current Understanding of These Mutations in the Motor

Moore, Jeffrey R.; Leinwand, Leslie; Warshaw, David M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 20/07/2012 Português
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Hypertrophic (HCM) and dilated (DCM) cardiomyopathies are inherited diseases with a high incidence of death due to electrical abnormalities or outflow tract obstruction. In many of the families afflicted with either disease, causative mutations have been identified in various sarcomeric proteins. In this review, we focus on mutations in the cardiac muscle molecular motor, myosin and its associated light chains. Despite the >300 identified mutations there is still no clear understanding of how these mutations within the same myosin molecule can lead to the dramatically different clinical phenotypes associated with HCM and DCM. Localizing mutations within myosin’s molecular structure provides insight into the potential consequence of these perturbations to key functional domains of the motor. Review of biochemical and biophysical data that characterize the functional capacities of these mutant myosins suggests that mutant myosins with enhanced contractility lead to HCM while those displaying reduced contractility lead to DCM. With gain and loss of function potentially being the primary consequence of a specific mutation, how these functional changes trigger the hypertrophic response and lead to the distinct HCM and DCM phenotypes will be the future investigative challenge.

‣ Book review of “Imaging in Cellular and Tissue Engineering” edited by Y Hanry Yu and Nur Aida Abdul Rahim

Brey, Eric Michael
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 23/06/2014 Português
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This article is a review of the book “Imaging in Cellular and Tissue Engineering” (ISBN-13: 978-1439848036, $149.95, 298 Pages, 114 Illustrations) edited by Y Hanry Yu and Nur Aida Abdul Rahim published by the CRC Press (Taylor&Francis) in 2013. The contents of the book and its relevance to tissue engineering and regenerative medicine are discussed in this invited review.

‣ Transcranial magnetic stimulation: potential treatment for co-occurring alcohol, traumatic brain injury and posttraumatic stress disorders

Herrold, Amy A.; Kletzel, Sandra L.; Harton, Brett C.; Chambers, R. Andrew; Jordan, Neil; Pape, Theresa Louise-Bender
Fonte: Medknow Publications & Media Pvt Ltd Publicador: Medknow Publications & Media Pvt Ltd
Tipo: Artigo de Revista Científica
Publicado em 01/10/2014 Português
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Alcohol use disorder (AUD), mild traumatic brain injury (mTBI), and posttraumatic stress disorder (PTSD) commonly co-occur (AUD + mTBI + PTSD). These conditions have overlapping symptoms which are, in part, reflective of overlapping neuropathology. These conditions become problematic because their co-occurrence can exacerbate symptoms. Therefore, treatments must be developed that are inclusive to all three conditions. Repetitive transcranial magnetic stimulation (rTMS) is non-invasive and may be an ideal treatment for co-occurring AUD + mTBI + PTSD. There is accumulating evidence on rTMS as a treatment for people with AUD, mTBI, and PTSD each alone. However, there are no published studies to date on rTMS as a treatment for co-occurring AUD + mTBI + PTSD. This review article advances the knowledge base for rTMS as a treatment for AUD + mTBI + PTSD. This review provides background information about these co-occurring conditions as well as rTMS. The existing literature on rTMS as a treatment for people with AUD, TBI, and PTSD each alone is reviewed. Finally, neurobiological findings in support of a theoretical model are discussed to inform TMS as a treatment for co-occurring AUD + mTBI + PTSD. The peer-reviewed literature was identified by targeted literature searches using PubMed and supplemented by cross-referencing the bibliographies of relevant review articles. The existing evidence on rTMS as a treatment for these conditions in isolation...

‣ Animal board invited review: genetic possibilities to reduce enteric methane emissions from ruminants

Pickering, N. K.; Oddy, V. H.; Basarab, J.; Cammack, K.; Hayes, B.; Hegarty, R. S.; Lassen, J.; McEwan, J. C.; Miller, S.; Pinares-Patiño, C. S.; de Haas, Y.
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica
Português
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Measuring and mitigating methane (CH4) emissions from livestock is of increasing importance for the environment and for policy making. Potentially, the most sustainable way of reducing enteric CH4 emission from ruminants is through the estimation of genomic breeding values to facilitate genetic selection. There is potential for adopting genetic selection and in the future genomic selection, for reduced CH4 emissions from ruminants. From this review it has been observed that both CH4 emissions and production (g/day) are a heritable and repeatable trait. CH4 emissions are strongly related to feed intake both in the short term (minutes to several hours) and over the medium term (days). When measured over the medium term, CH4 yield (MY, g CH4/kg dry matter intake) is a heritable and repeatable trait albeit with less genetic variation than for CH4 emissions. CH4 emissions of individual animals are moderately repeatable across diets, and across feeding levels, when measured in respiration chambers. Repeatability is lower when short term measurements are used, possibly due to variation in time and amount of feed ingested prior to the measurement. However, while repeated measurements add value; it is preferable the measures be separated by at least 3 to 14 days. This temporal separation of measurements needs to be investigated further. Given the above issue can be resolved...

‣ Review of "Biomedical Informatics; Computer Applications in Health Care and Biomedicine" by Edward H. Shortliffe and James J. Cimino

Clifford, Gari D
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 21/11/2006 Português
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This article is an invited review of the third edition of "Biomedical Informatics; Computer Applications in Health Care and Biomedicine", one of thirty-six volumes in Springer's 'Health Informatics Series', edited by E. Shortliffe and J. Cimino. This book spans most of the current methods and issues in health informatics, ranging through subjects as varied as data acquisition and storage, standards, natural language processing, imaging, electronic health records, decision support, teaching methods and ethics. The book is aimed at 'healthcare professionals', and is certainly appropriate for the non-technical informatics user. However, this book is also excellent background reading for the technical engineer who may be interested in the possible problems that confront the users in this field.

‣ Models of Particle Physics from Type IIB String Theory and F-theory: A Review

Maharana, Anshuman; Palti, Eran
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/12/2012 Português
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We review particle physics model building in type IIB string theory and F-theory. This is a region in the landscape where in principle many of the key ingredients required for a realistic model of particle physics can be combined successfully. We begin by reviewing moduli stabilisation within this framework and its implications for supersymmetry breaking. We then review model building tools and developments in the weakly coupled type IIB limit, for both local D3-branes at singularities and global models of intersecting D7-branes. Much of recent model building work has been in the strongly coupled regime of F-theory due to the presence of exceptional symmetries which allow for the construction of phenomenologically appealing Grand Unified Theories. We review both local and global F-theory model building starting from the fundamental concepts and tools regarding how the gauge group, matter sector and operators arise, and ranging to detailed phenomenological properties explored in the literature.; Comment: 79 pages, Invited review article for the International Journal of Modern Physics A

‣ Experimental Discovery of Topological Surface States - A New Type of 2D Electron Systems (Review Article)

Hasan, M. Zahid; Xu, Su-Yang; Hsieh, David; Wray, L. Andrew; Xia, Yuqi
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 04/01/2014 Português
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Topological Surface States (TSS) represent new types of two dimensional electron systems with novel and unprecedented properties distinct from any quantum Hall-like or spin-Hall effects. Their Z$_2$ topological order can be realized at room temperatures without magnetic fields and they can be turned into magnets, exotic superconductors or Kondo insulators leading to worldwide interest and activity in the topic. We review the basic concepts defining such topological matter and the experimental discovery via the key experimental probe that revealed the Z$_2$ topological order in the bulk of these spin-orbit interaction dominated insulators for the first time. This review focuses on the key results that demonstrated the fundamental Z$_2$ topological properties such as spin-momentum locking, non-trivial Berry's phases, mirror Chern number, absence of backscattering, bulk-boundary correspondence (topology), protection by time-reversal and other discrete (mirror) symmetries and their remarkable persistence up to the room temperature elaborating on results first briefly discussed in an early review by M.Z. Hasan and C.L. Kane [Rev. of Mod. Phys., 82, 3045 (2010)]. Additionally, key results on broken symmetry phases such as quantum magnetism and superconductivity induced in topological materials are briefly discussed. Topological insulators beyond the Z$_2$ classification such as Topological Crystalline Insulators (TCI) are discussed based on their spin properties (mirror Chern invariants). The experimental methodologies detailed here have been used in most of the subsequent studies of Z$_2$ topological physics in almost all bulk topological insulator materials to this date.; Comment: 18 Figures...

‣ Microscopic Theory of Nuclear Fission: A Review

Schunck, N.; Robledo, L. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 23/11/2015 Português
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This article reviews how nuclear fission is described within nuclear density functional theory. In spontaneous fission, half-lives are the main observables and quantum tunnelling the essential concept, while in induced fission the focus is on fragment properties and explicitly time-dependent approaches are needed. The cornerstone of the current microscopic theory of fission is the energy density functional formalism. Its basic tenets, including tools such as the HFB theory, effective two-body effective nuclear potentials, finite-temperature extensions and beyond mean-field corrections, are presented succinctly. The EDF approach is often combined with the hypothesis that the time-scale of the large amplitude collective motion driving the system to fission is slow compared to typical time-scales of nucleons inside the nucleus. In practice, this hypothesis of adiabaticity is implemented by introducing (a few) collective variables and mapping out the many-body Schr\"odinger equation into a collective Schr\"odinger-like equation for the nuclear wave-packet. Scission configurations indicate where the split occurs. This collective Schr\"odinger equation depends on an inertia tensor that includes the response of the system to small changes in the collective variables and also plays a special role in the determination of spontaneous fission half-lives. A trademark of the microscopic theory of fission is the tremendous amount of computing needed for practical applications. In particular...

‣ Bayesian Model Averaging in Astrophysics: A Review

Parkinson, David; Liddle, Andrew R.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/02/2013 Português
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We review the use of Bayesian Model Averaging in astrophysics. We first introduce the statistical basis of Bayesian Model Selection and Model Averaging. We discuss methods to calculate the model-averaged posteriors, including Markov Chain Monte Carlo (MCMC), nested sampling, Population Monte Carlo, and Reversible Jump MCMC. We then review some applications of Bayesian Model Averaging in astrophysics, including measurements of the dark energy and primordial power spectrum parameters in cosmology, cluster weak lensing and Sunyaev-Zel'dovich effect data, estimating distances to Cepheids, and classifying variable stars.; Comment: 16 pages, 5 figures. Invited review article for special issue on Astrostatistics

‣ A review of elliptical and disc galaxy structure, and modern scaling laws

Graham, Alister W.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 04/08/2011 Português
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A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.; Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets...

‣ A Review of Symmetry Algebras of Quantum Matrix Models in the Large-N Limit

Lee, C. -W. H.; Rajeev, S. G.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 08/06/1999 Português
Relevância na Pesquisa
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This is a review article in which we will introduce, in a unifying fashion and with more intermediate steps in some difficult calculations, two infinite-dimensional Lie algebras of quantum matrix models, one for the open string sector and one for the closed string sector. Physical observables of quantum matrix models in the large-N limit can be expressed as elements of these Lie algebras. We will see that both algebras arise as quotient algebras of a larger Lie algebra. We will also discuss some properties of these Lie algebras not published elsewhere yet, and briefly review their relationship with well-known algebras like the Cuntz algebra, the Witt algebra and the Virasoro algebra. We will also review how Yang--Mills theory, various low energy effective models of string theory, quantum gravity, string-bit models, and quantum spin chain models can be formulated as quantum matrix models. Studying these algebras thus help us understand the common symmetry of these physical systems.; Comment: 77 pages, 21 eps figures, 1 table, LaTeX2.09; an invited review article