595 research outputs found

    The new nuclear arms control environment : trip report and project conclusions

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    Includes bibliographical references. "July 2002"This paper reports the results of 9 conference, workshops and private meetings held on the current diplomatic and security problems associated with nuclear arms control, both before and after September 11. Appendixes include participants and questions.unpublishednot peer reviewe

    Semantics of the visual environment encoded in parahippocampal cortex

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    Semantic representations capture the statistics of experience and store this information in memory. A fundamental component of this memory system is knowledge of the visual environment, including knowledge of objects and their associations. Visual semantic information underlies a range of behaviors, from perceptual categorization to cognitive processes such as language and reasoning. Here we examine the neuroanatomic system that encodes visual semantics. Across three experiments, we found converging evidence indicating that knowledge of verbally mediated visual concepts relies on information encoded in a region of the ventral-medial temporal lobe centered on parahippocampal cortex. In an fMRI study, this region was strongly engaged by the processing of concepts relying on visual knowledge but not by concepts relying on other sensory modalities. In a study of patients with the semantic variant of primary progressive aphasia (semantic dementia), atrophy that encompassed this region was associated with a specific impairment in verbally mediated visual semantic knowledge. Finally, in a structural study of healthy adults from the fMRI experiment, gray matter density in this region related to individual variability in the processing of visual concepts. The anatomic location of these findings aligns with recent work linking the ventral-medial temporal lobe with high-level visual representation, contextual associations, and reasoning through imagination. Together this work suggests a critical role for parahippocampal cortex in linking the visual environment with knowledge systems in the human brain

    Preparation of Novel Hydroxyethyl Amine Isosteres as Potential Cathepsin D Inhibitors

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    Cathepsin D is a lysosomal aspartic protease found in all mammalian cells and is considered to be one of the main catabolic proteinases. Cathepsin D has been suggested to play a role in the metastatic potential of several types of cancer. A high activated cathepsin D level in breast tumor tissue has been associated with an increased incidence of relapse and metastasis. High levels of active cathepsin D have also been found in colon cancer, prostate cancer, uterine cancer, and ovarian cancer. Hydroxyethyl isosteres with cyclic tertiary amine have proven to be clinically useful as inhibitors of aspartyl proteases similar to cathepsin D inactivity, such as the HIV-1 aspartyl protease. We have undertaken the design, via computer molecular modeling, and the synthesis of (hydroxyethyl) amine isostere inhibitors, which are similar to potent inhibitors of the aspartyl HIV-1 protease. We now report the preparation of six compounds that contain novel hydroxyethyl isosteres with cyclic tertiary amines

    Causal evidence for a mechanism of semantic integration in the angular gyrus as revealed by high-definition transcranial direct current stimulation

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    A defining aspect of human cognition is the ability to integrate conceptual information into complex semantic combinations. For example, we can comprehend “plaid” and “jacket” as individual concepts, but we can also effortlessly combine these concepts to form the semantic representation of “plaid jacket.” Many neuroanatomic models of semantic memory propose that heteromodal cortical hubs integrate distributed semantic features into coherent representations. However, little work has specifically examined these proposed integrative mechanisms and the causal role of these regions in semantic integration. Here, we test the hypothesis that the angular gyrus (AG) is critical for integrating semantic information by applying high-definition transcranial direct current stimulation (tDCS) to an fMRI-guided region-of-interest in the left AG. We found that anodal stimulation to the left AG modulated semantic integration but had no effect on a letter-string control task. Specifically, anodal stimulation to the left AG resulted in faster comprehension of semantically meaningful combinations like “tiny radish” relative to non-meaningful combinations, such as “fast blueberry,” when compared to the effects observed during sham stimulation and stimulation to a right-hemisphere control brain region. Moreover, the size of the effect from brain stimulation correlated with the degree of semantic coherence between the word pairs. These findings demonstrate that the left AG plays a causal role in the integration of lexical-semantic information, and that high-definition tDCS to an associative cortical hub can selectively modulate integrative processes in semantic memory. SIGNIFICANCE STATEMENT A major goal of neuroscience is to understand the neural basis of behaviors that are fundamental to human intelligence. One essential behavior is the ability to integrate conceptual knowledge from semantic memory, allowing us to construct an almost unlimited number of complex concepts from a limited set of basic constituents (e.g., “leaf” and “wet” can be combined into the more complex representation “wet leaf”). Here, we present a novel approach to studying integrative processes in semantic memory by applying focal brain stimulation to a heteromodal cortical hub implicated in semantic processing. Our findings demonstrate a causal role of the left angular gyrus in lexical-semantic integration and provide motivation for novel therapeutic applications in patients with lexical-semantic deficits

    Co-polymers of Furan with Pyrrole or Thiophene: A Synthetic Study

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    The use of conductive polymers as a substitute for metallic conductors and semiconductors has attracted much attention in the literature. In particular, aromatic heterocyclic polymers constitute an important class since they possess chemical and electrical stability in both the oxidized (doped) and neutral (undoped) state. Doping a polymer allows one to vary its electrical, mechanical, optical, and thermal properties. The properties of these polymers are promising for their many technological uses such as antistatic coatings, solar cells, and electronic devises. Polyfuran is among the least common heterocyclic polymers. Polyfuran has been reported to be much less stable that either polypyrrole or polythiophene. The preparation of co-polymers of polyfuran with two percent pyrrole or thiophene is reported. The polymers are characterized by *HNMR, IR, and ESR spectroscopy, and the electrical conductivity of the doped and un-doped synthetic polyfuran and co-polymers is provided

    Office bladder distention with Electromotive Drug Administration (EMDA) is equivalent to distention under General Anesthesia (GA)

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    BACKGROUND: Bladder distention is commonly used in diagnosis and treatment of interstitial cystitis (IC). Traditionally performed in the operating room under general or spinal anesthesia (GA), it is expensive and associated with short term morbidity. Office bladder distention using electromotive drug administration (EMDA) has been suggested as an alternative that is well tolerated by patients. We report the first comparative findings of patients undergoing both office distention with EMDA and distention in the operating room (OR) with GA. METHODS: This retrospective chart review identified 11 patients participating in two protocols of EMDA bladder distention who also underwent bladder distention under GA either prior to or after the EMDA procedure. RESULTS: The median absolute difference in bladder capacity between GA and EMDA was only 25 cc; the median percent difference was 5%. Cystoscopic findings, while not prospectively compiled, appear to have been similar. CONCLUSION: This study represents the first comparison between distention with EMDA versus GA and confirms the technical feasibility of performing bladder distention in an office setting. The distention capacity achieved in the office was nearly identical to that in the OR and the cystoscopic findings very similar. Further investigation into the comparative morbidity, cost, and other outcome measures is warranted to define the ultimate role of EMDA bladder distention in the clinical evaluation and care of patients with IC

    KINEMATIC AND KINETIC ANALYSIS OF THE ELITE GOLF SWING

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    The purpose of this study was to determine the association between select biomechanical variables and clubhead speed at impact (CSI) in a sample of elite golfers. Power generation is thought to arise from a number of factors including body rotation and weight shift. CSI is often used to indicate power generation (Fradkin, et al., 2004). We hypothesized that CSI would be highly related to torque, relative hip-shoulder rotation (X-factor) and weight shift during the golf swing

    Earliest Eocene mammalian fauna from the Paleocene-Eocene Thermal Maximum at Sand Creek Divide, southern Bighorn Basin, Wyoming

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    http://deepblue.lib.umich.edu/bitstream/2027.42/89881/1/Papers On Paleontology 36 02-15-2012.pd
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