604 research outputs found

    Improving the Inventory of Large Lunar Basins: Using LOLA Data to Test Previous Candidates and Search for New Ones

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    Topography and crustal thickness data from LOLA altimetry were used to test the validity of 98 candidate large lunar basins derived from photogeologic and earlier topographic and crustal thickness data, and to search for possible new candidates. We eliminate 23 previous candidates but find good evidence for 20 new candidates. The number of basins greater than 300 km diameter on the Moon is almost certainly a factor 2 (maybe 3?) larger than the number of named features having basin-like topography. Unified Lunar Control Net 2005 data [1] and model crustal thickness data [2] were previously used to search for possible previously unrecognized large lunar impact basins [3,4]. An inventory of 98 candidate topographic basins greater than 300 km in diameter was found [5]. This includes 33 named features (only those having basin-like topography) out of the 45 listed by Wilhelms [6], 38 additional Quasi-Circular Depressions (QCDs) found in the ULCN2005 topography, and 27 Circular Thin Areas (CTAs) found in model crustal thickness data [2]. Most named features and additional QCDs have strong CTA signatures, but there may be a class of CTAs that are not easily recognized in the old and low resolution ULCN2005 topography. Lunar Orbiter Laser Altimeter (LOLA) data have recently become publically available. We used these data to (a) refine the center and ring diameters of known basins, (b) test the viability of the candidate basins previously found (as described above), and (c) search for additional candidate basins not revealed by the earlier lower resolution data. We used the LOLA topography directly but also a recent new model crustal thickness data that includes Kaguya gravity data [7]. We repeated a Topographic Expression (TE) and a Crustal Thickness Expression (CTE) scoring exercise originally done with the basins found in ULCN and earlier model crustal thickness data [5]. Each candidate was scored on a scale from 0 (no topographic basin or circular thin area signature) to 5 (strong circular low or strong circular thin area signature). These were combined into a total score used to rank the probability for each candidate basin. We used the same GRIDVIEW software to stretch, contour and profile the LOLA and new crustal thickness data as was done with the ULCN2005 and older model crustal thickness data

    A Combined Experimental and Analytical Modeling Approach to Understanding Friction Stir Welding

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    In the Friction Stir Welding (FSW) process a rotating pin tool joins the sides of a seam by stirring them together. This solid state welding process avoids problems with melting and hot-shortness presented by some difficult-to weld high-performance light alloys. The details of the plastic flow during the process are not well understood and are currently a subject of research. Two candidate models of the FSW process, the Mixed Zone (MZ) and the Single Slip Surface (S3) model are presented and their predictions compared to experimental data

    The Role of Maternal Gesture Use in Speech Use by Children with Fragile X Syndrome

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    Purpose--The purpose of this study was to investigate how maternal gesture relates to speech production by children with fragile X syndrome (FXS). Method--Participants were 27 young children with FXS (23 boys, 4 girls) and their mothers. Videotaped home observations were conducted between the ages of 25 and 37 months (toddler period), and again between the ages of 60 and 71 months (child period). The videos were later coded for types of maternal utterances and maternal gestures that preceded child speech productions. Children were also assessed with the Mullen Scales of Early Learning at both ages Results--Maternal gesture use in the toddler period was positively related to expressive language scores at both age periods, and was related to receptive language scores in the child period. Maternal proximal pointing, in comparison to other gestures, evoked more speech responses from children during the mother-child interactions particularly when combined with wh-questions. Conclusion-- This study adds to the growing body of research on the importance of contextual variables, such as maternal gestures, in child language development. Parental gesture use may be an easily added ingredient to parent-focused early language intervention programs

    Systemic TLR2 agonist exposure regulates hematopoietic stem cells via cell-autonomous and cell-non-autonomous mechanisms

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    Toll-like receptor 2 (TLR2) is a member of the TLR family of receptors that play a central role in innate immunity. In addition to regulating effector immune cells, where it recognizes a wide variety of pathogen-associated and nonpathogen-associated endogenous ligands, TLR2 is expressed in hematopoietic stem cells (HSCs). Its role in HSCs, however, is not well understood. Furthermore, augmented TLR2 signaling is associated with myelodysplastic syndrome, an HSC disorder characterized by ineffective hematopoiesis and a high risk of transformation to leukemia, suggesting that aberrant signaling through this receptor may have clinically significant effects on HSCs. Herein, we show that systemic exposure of mice to a TLR2 agonist leads to an expansion of bone marrow and spleen phenotypic HSCs and progenitors, but a loss of HSC self-renewal capacity. Treatment of chimeric animals shows that these effects are largely cell non-autonomous, with a minor contribution from cell-autonomous TLR2 signaling, and are in part mediated by granulocyte colony-stimulating factor and tumor necrosis factor-α. Together, these data suggest that TLR2 ligand exposure influences HSC cycling and function via unique mechanisms from TLR4, and support an important role for TLR2 in the regulation of HSCs

    Evaluating associations between fitspiration and thinspiration content on Instagram and disordered-eating behaviors using ecological momentary assessment: A registered report

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    This is the peer reviewed version of the following article: Christensen, KA, Forbush, KT, Cushing, CC, Lejuez, CW, Fleming, KK, Swinburne Romine, RE. Evaluating associations between fitspiration and thinspiration content on Instagram and disordered-eating behaviors using ecological momentary assessment: A registered report. Int J Eat Disord. 2021; 54: 1307– 1315. https://doi.org/10.1002/eat.23518, which has been published in final form at https://doi.org/10.1002/eat.23518. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.Introduction Greater use of appearance-focused social media, such as Instagram, is associated with increased body dissatisfaction and eating disorder (ED) symptoms; however, questions remain about the mechanism connecting social media use to disordered-eating behaviors (DEBs). The proposed study evaluates how and for whom exposure to fitspiration or thinspiration on Instagram is associated with DEBs. Methods We will evaluate a hypothesized pathway from Instagram use to disordered-eating mediated by negative affect. We will test how individual differences in internalized weight stigma, trait self-esteem, and trait self-comparison moderate the pathway from social media use to negative affect. We will recruit 175 undergraduate women who report engaging in DEBs on average at least once per week over the past 3 months. Participants will complete a 7-day ecological momentary assessment protocol, during which they will report their Instagram use, affect, and engagement in DEBs. Results Multi-level modeling will be used to assess moderated mediation. Results from this study will provide increased specificity about how Instagram usage is linked to eating pathology and who may be most vulnerable to experiencing distress. Discussion Information about negative affect from Instagram and engagement in DEBs could contribute to the development of Just-In-Time Interventions for problematic social media use

    Potential Alzheimer’s Disease Therapeutics Among Weak Cysteine Protease Inhibitors Exhibit Mechanistic Differences Regarding Extent of Cathepsin B Up-Regulation and Ability to Block Calpain

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    Cysteine protease inhibitors have long been part of drug discovery programs for Alzheimer's disease (AD), traumatic brain injury (TBI), and other disorders. Select inhibitors reduce accumulating proteins and AD pathology in mouse models. One such compound, Z-Phe-Aladiazomethylketone (PADK), exhibits a very weak IC50 (9-11 μM) towards cathepsin B (CatB), but curiously PADK causes marked up-regulation of the Aβ-degrading CatB and improves spatial memory. Potential therapeutic and weak inhibitor E64d (14 μM IC50) also up-regulates CatB. PADK and E64d were compared regarding the blockage of calcium-induced cytoskeletal deterioration in brain samples, monitoring the 150-kDa spectrin breakdown product (SBDP) known to be produced by calpain. PADK had little to no effect on SBDP production at 10-100 μM. In contrast, E64d caused a dosedependent decline in SBDP levels with an IC50 of 3-6 μM, closely matching its reported potency for inhibiting μ-calpain. Calpain also cleaves the cytoskeletal organizing protein gephyrin, producing 49-kDa (GnBDP49) and 18-kDa (GnBDP18) breakdown products. PADK had no apparent effect on calcium-induced gephyrin fragments whereas E64d blocked their production. E64d also protected the parent gephyrin in correspondence with reduced BDP levels. The findings of this study indicate that PADK’s positive and selective effects on CatB are consistent with human studies showing exercise elevates CatB and such elevation correlates with improved memory. On the other hand, E64d exhibits both marginal CatB enhancement and potent calpain inhibition. This dual effect may be beneficial for treating AD. Alternatively, the potent action on calpain-related pathology may explain E64d’s protection in AD and TBI models

    Investıgatıon of Removal of Dye from Aqueous Solutıon by Advanced Treatment

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    The textile dyeing and finishing industry use a significant amount of water and produce water pollution. Conventional biological treatment processes have some difficulties for degradation of nonbiodegradable compounds. Dye-bearing wastewaters have high COD and colour. In this study, a photo reactor process was used to remove color from aqueous solution.Effects of pH on Reactive Red 4 and cationic dye removal using 1g/L TiO2, as catalyst were studied at constant inital dye concentration (25 mg/l). Cationic dye removal efficiency is better than Reactive dye removal efficiency for photocatalytic oxidation in this stud

    Prospectus, July 1, 1991

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    https://spark.parkland.edu/prospectus_1991/1009/thumbnail.jp

    Sodium Hydroxide Catalyzed Dehydrocoupling of Alcohols with Hydrosilanes

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    An O–Si bond construction protocol employing abundantly available and inexpensive NaOH as the catalyst is described. The method enables the cross-dehydrogenative coupling of an alcohol and hydrosilane to directly generate the corresponding silyl ether under mild conditions and without the production of stoichiometric salt byproducts. The scope of both coupling partners is excellent, positioning the method for use in complex molecule and materials science applications. A novel Si-based cross-coupling reagent is also reported
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