11,708 research outputs found
Dear brother letters of William Clark to Jonathan Clark
No full textOver the course of his career, American explorer William Clark (1770-1838) wrote at least forty-five letters to his older brother Jonathan, including six that were written during the epic Lewis and Clark Expedition. This book publishes many of these letters for the first time, revealing important details about the expedition, the mysterious death of Meriwether Lewis, the status of Clark's slave York (the first African American known to have crossed the continent from coast to coast), and other matters of historical significance. There are letters concerning the establishment of the Corps of Discovery's first winter camp in December 1803, preparations for setting out into the country west of Fort Mandan in 1805, and Clark's 1807 fossil dig at Big Bone Lick, Kentucky. There are also letters about Lewis's disturbed final days that shed light on whether he committed suicide or was murdered. Still other letters chronicle the fate of York after the expedition; we learn the details of Clark and York's falling out and subsequent alienation. Together the letters and the introductions and annotations by James J. Holmberg provide valuable insights into the lives of Lewis and Clark and the world of Jeffersonian America
The Yellow Slicker: A Fable for Women
No full textEach of eleven pages of text in this large-format book is matched with a full-page black-and-white line illustration, almost always of a nude woman. The story starts when a man asks a woman why she is wearing a yellow slicker on a sunny day. The answer is Well, I'd rather wear nothing, but since that is not the custom, I wear this raincoat. He gets her lovely clothes and throws away her yellow slicker. At his invitation, she follows him to his country to be his wife. After some time of difficult loneliness and efforts to please him--and to hide the yellow slicker that she surreptitiously recovered--she leaves him and his gifts, writing that she cannot please him any more. The back of the dj reminds us that A fable is a cautionary tale. It offers the reader a bit of information from which a lesson can be drawn. I think one of the most easily perceived lessons here is about pleasing other people at the cost of giving away oneself. I will need some time to appreciate how the nudes enhance the story. I had seen this book mentioned a number of times, and am glad to have put my hands on it.This is a hardbound book (hard cover)This book has a dust jacket (book cover)First editionFirst printingStory and Original Art by Pegi Clark Pearso
“Greening” Worcester: Municipal Best Practices for Sustainability
No full textIn response to the urgent threat posed by climate change, more and more cities, including Worcester, are attempting to become more environmentally responsible and sustainable. Worcester is attempting to develop ways to become more sustainable; both to strengthen their communities and to protect the planet. The Green Worcester Working Group (GWWG) tasked the Clark Capstone Team with researching best practices for municipal sustainability. The GWWG has set the following priorities: climate change mitigation, resilience, open spaces, sustainable resource management, education and awareness. Taking these into account, the Clark Capstone Team researched the sustainability practices of cities in New England, across the U.S., and around the world, gathering and synthesizing the information found. Through careful data evaluation, the team selected six cities to recommend: Portsmouth, NH; Cambridge, MA; Bridgeport, CT; Somerville, MA; Seattle, WA; and New York, NY
Application of CT in Diagnosing Carcinoma of the Maxillary Sinuses : PART 2: An Experimental Study of Pitfalls Encountered when Diagnosing Carcinoma of the Maxillary Sinuses with CT
No full text1982-03A phantom simulating the transverse section of the maxillary sinuses was constructed for experimentation with various CT scanners to study the following: (1) the occasional inability to image the very thin posterior-lateral walls which have no real bone defects, and (2) to verify whether or not the bony walls surrounding the maxillary sinuses are actually as thick as they appear on CT. The phantom was made of an acrylic cylinder containing three cavities simulating the maxillary sinuses and the nasal cavity and filled with water. The walls, made of thin aluminum and acrylic plates and placed between water and air, disappeared in some CT images. The thickness of the walls calculated from CT values was greater than the true thickness imaged by each CT scanner. The author stresses that in CT images, either experimentally or clinically, thin bony walls placed between water and air or fat tend to disappear, and that bony walls tend to appear thicker than their true thickenss.departmental bulletin pape
Micro-CT of rodents: state-of-the-art and future perspectives.
No full textMicron-scale computed tomography (micro-CT) is an essential tool for phenotyping and for elucidating diseases and their therapies. This work is focused on preclinical micro-CT imaging, reviewing relevant principles, technologies, and applications. Commonly, micro-CT provides high-resolution anatomic information, either on its own or in conjunction with lower-resolution functional imaging modalities such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). More recently, however, advanced applications of micro-CT produce functional information by translating clinical applications to model systems (e.g., measuring cardiac functional metrics) and by pioneering new ones (e.g. measuring tumor vascular permeability with nanoparticle contrast agents). The primary limitations of micro-CT imaging are the associated radiation dose and relatively poor soft tissue contrast. We review several image reconstruction strategies based on iterative, statistical, and gradient sparsity regularization, demonstrating that high image quality is achievable with low radiation dose given ever more powerful computational resources. We also review two contrast mechanisms under intense development. The first is spectral contrast for quantitative material discrimination in combination with passive or actively targeted nanoparticle contrast agents. The second is phase contrast which measures refraction in biological tissues for improved contrast and potentially reduced radiation dose relative to standard absorption imaging. These technological advancements promise to develop micro-CT into a commonplace, functional and even molecular imaging modality
Advances in Micro-CT Imaging of Small Animals
No full textPURPOSE: Micron-scale computed tomography (micro-CT) imaging is a ubiquitous, cost-effective, and non-invasive three-dimensional imaging modality. We review recent developments and applications of micro-CT for preclinical research. METHODS: Based on a comprehensive review of recent micro-CT literature, we summarize features of state-of-the-art hardware and ongoing challenges and promising research directions in the field. RESULTS: Representative features of commercially available micro-CT scanners and some new applications for both in vivo and ex vivo imaging are described. New advancements include spectral scanning using dual-energy micro-CT based on energy-integrating detectors or a new generation of photon-counting x-ray detectors (PCDs). Beyond two-material discrimination, PCDs enable quantitative differentiation of intrinsic tissues from one or more extrinsic contrast agents. When these extrinsic contrast agents are incorporated into a nanoparticle platform (e.g. liposomes), novel micro-CT imaging applications are possible such as combined therapy and diagnostic imaging in the field of cancer theranostics. Another major area of research in micro-CT is in x-ray phase contrast (XPC) imaging. XPC imaging opens CT to many new imaging applications because phase changes are more sensitive to density variations in soft tissues than standard absorption imaging. We further review the impact of deep learning on micro-CT. We feature several recent works which have successfully applied deep learning to micro-CT data, and we outline several challenges specific to micro-CT. CONCLUSIONS: All of these advancements establish micro-CT imaging at the forefront of preclinical research, able to provide anatomical, functional, and even molecular information while serving as a testbench for translational research
FIGURE 1 in Pseudolitochira integra (Miers, 1884) (Crustacea: Brachyura: Pilumnidae): redescribed and illustrated from micro-CT scanning the type female
No full textFIGURE 1. The container designed to hold crab samples during micro-CT scanning.Published as part of Ng, Peter K.L., Clark, Paul F., Clark, Brett & Kamanli, Seyit A., 2021, Pseudolitochira integra (Miers, 1884) (Crustacea: Brachyura: Pilumnidae): redescribed and illustrated from micro-CT scanning the type female, pp. 377-391 in Zootaxa 4969 (2) on page 379, DOI: 10.11646/zootaxa.4969.2.9, http://zenodo.org/record/474923
Dual source hybrid spectral micro-CT using an energy-integrating and a photon-counting detector.
No full textPreclinical micro-CT provides a hotbed in which to develop new imaging technologies, including spectral CT using photon counting detector (PCD) technology. Spectral imaging using PCDs promises to expand x-ray CT as a functional imaging modality, capable of molecular imaging, while maintaining CT's role as a powerful anatomical imaging modality. However, the utility of PCDs suffers due to distorted spectral measurements, affecting the accuracy of material decomposition. We attempt to improve material decomposition accuracy using our novel hybrid dual-source micro-CT system which combines a PCD and an energy integrating detector. Comparisons are made between PCD-only and hybrid CT results, both reconstructed with our iterative, multi-channel algorithm based on the split Bregman method and regularized with rank-sparse kernel regression. Multi-material decomposition is performed post-reconstruction for separation of iodine (I), gold (Au), gadolinium (Gd), and calcium (Ca). System performance is evaluated first in simulations, then in micro-CT phantoms, and finally in an in vivo experiment with a genetically modified p53fl/fl mouse cancer model with Au, Gd, and I nanoparticle (NP)-based contrasts agents. Our results show that the PCD-only and hybrid CT reconstructions offered very similar spatial resolution at 10% MTF (PCD: 3.50 lp mm-1; hybrid: 3.47 lp mm-1) and noise characteristics given by the noise power spectrum. For material decomposition we note successful separation of the four basis materials. We found that hybrid reconstruction reduces RMSE by an average of 37% across all material maps when compared to PCD-only of similar dose but does not provide much difference in terms of concentration accuracy. The in vivo results show separation of targeted Au and accumulated Gd NPs in the tumor from intravascular iodine NPs and bone. Hybrid spectral micro-CT can benefit nanotechnology and cancer research by providing quantitative imaging to test and optimize various NPs for diagnostic and therapeutic applications
Defining the future of quantitative SPECT/CT
No full textSingle photon emission tomography computed tomography (SPECT/CT) imaging, with its innate ability to detect and characterise abnormalities in their earliest forms, can be a meaningful tool for determining prompt diagnoses and developing personalised treatment strategies. Such a tool is invaluable as we move towards precision medicine, and the significant addition of reliable quantitative measurements only enhances SPECT/CT’s opportunities. Quantitative SPECT/CT looks to establish an active role in the next era of healthcare, but the extent of its impact continues to be defined
A component analysis of cognitive-behavioral treatment for depression
No full textThe purpose of this study was to provide an experimental test of the theory of change put forth by A. T. Beck, A. J. Rush, B. F. Shaw, and G. Emery (1979) to explain the efficacy of cognitive-behavioral therapy (CT) for depression. The comparison involved randomly assigning 150 outpatients with major depression to a treatment focused exclusively on the behavioral activation (BA) component of CT, a treatment that included both BA and the teaching of skills to modify automatic thoughts (AT), but excluding the components of CT focused on core schema, or the full CT treatment. Four experienced cognitive therapists conducted all treatments. Despite excellent adherence to treatment protocols by the therapists, a clear bias favoring CT, and the competent performance of CX there was no evidence that the complete treatment produced better outcomes, at either the termination of acute treatment or the 6-month follow-up, than either component treatment. Furthermore, both BA and AT treatments were just as effective as CT at altering negative thinking as well as dysfunctional attributional styles. Finally, attributional style was highly predictive of both short- and long-term outcomes in the BA condition, but not in the CT condition
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