279 research outputs found

    Wing Leading Edge Concepts for Noise Reduction

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    This study focuses on the development of wing leading edge concepts for noise reduction during high-lift operations, without compromising landing stall speeds, stall characteristics or cruise performance. High-lift geometries, which can be obtained by conventional mechanical systems or morphing structures have been considered. A systematic aerodynamic analysis procedure was used to arrive at several promising configurations. The aerodynamic design of new wing leading edge shapes is obtained from a robust Computational Fluid Dynamics procedure. Acoustic benefits are qualitatively established through the evaluation of the computed flow fields

    Strained Silicon on Silicon by Wafer Bonding and Layer Transfer from Relaxed SiGe Buffer

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    We report the creation of strained silicon on silicon (SSOS) substrate technology. The method uses a relaxed SiGe buffer as a template for inducing tensile strain in a Si layer, which is then bonded to another Si handle wafer. The original Si wafer and the relaxed SiGe buffer are subsequently removed, thereby transferring a strained-Si layer directly to Si substrate without intermediate SiGe or oxide layers. Complete removal of Ge from the structure was confirmed by cross-sectional transmission electron microscopy as well as secondary ion mass spectrometry. A plan-view transmission electron microscopy study of the strained-Si/Si interface reveals that the lattice-mismatch between the layers is accommodated by an orthogonal array of edge dislocations. This misfit dislocation array, which forms upon bonding, is geometrically necessary and has an average spacing of approximately 40nm, in excellent agreement with established dislocation theory. To our knowledge, this is the first study of a chemically homogeneous, yet lattice-mismatched, interface.Singapore-MIT Alliance (SMA

    Is Whole-Body Cryostimulation an Effective Add-On Treatment in Individuals with Fibromyalgia and Obesity? A Randomized Controlled Clinical Trial

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    Pain severity, depression, and sleep disturbances are key targets for FM rehabilitation. Recent evidence suggests that whole-body cryostimulation (WBC) might be an effective add-on treatment in the management of FM. The purpose of this study was to evaluate the effects of an add-on WBC intervention to a multidisciplinary rehabilitation program on pain intensity, depressive symptoms, disease impact, sleep quality, and performance-based physical functioning in a sample of FM patients with obesity. We performed a randomized controlled trial with 43 patients with FM and obesity undergoing a multidisciplinary rehabilitation program with and without the addition of ten 2-min WBC sessions at −110 °C over two weeks. According to our results, the implementation of ten sessions of WBC over two weeks produced additional benefits. Indeed, both groups reported positive changes after the rehabilitation; however, the group that underwent WBC intervention had greater improvements in the severity of pain, depressive symptoms, disease impact, and quality of sleep. On the contrary, with respect to performance-based physical functioning, we found no significant between-group differences. Our findings suggest that WBC could be a promising add-on treatment to improve key aspects of FM, such as pain, depressive symptoms, disease impact and poor sleep quality

    Food discovery is associated with different reliance on social learning and lower cognitive flexibility across environments in a food-caching bird

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    Social learning is a primary mechanism for information acquisition in social species. Despite many benefits, social learning may be disadvantageous when independent learning is more efficient. For example, searching independently may be more advantageous when food sources are ephemeral and unpredictable. Individual differences in cognitive abilities can also be expected to influence social information use. Specifically, better spatial memory can make a given environment more predictable for an individual by allowing it to better track food sources. We investigated how resident food-caching chickadees discovered multiple novel food sources in both harsher, less predictable high elevation and milder, more predictable low elevation winter environments. Chickadees at high elevation were faster at discovering multiple novel food sources and discovered more food sources than birds at low elevation. While birds at both elevations used social information, the contribution of social learning to food discovery was significantly lower at high elevation. At both elevations, chickadees with better spatial cognitive flexibility were slower at discovering food sources, likely because birds with lower spatial cognitive flexibility are worse at tracking natural resources and therefore spend more time exploring. Overall, our study supported the prediction that harsh environments should favour less reliance on social learning

    Blended Wing Body Concept Development with Open Rotor Engine Intergration

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    The purpose of this study is to perform a systems analysis of a Blended Wing Body (BWB) open rotor concept at the conceptual design level. This concept will be utilized to estimate overall noise and fuel burn performance, leveraging recent test data. This study will also investigate the challenge of propulsion airframe installation of an open rotor engine on a BWB configuration. Open rotor engines have unique problems relative to turbofans. The rotors are open, exposed to flow conditions outside of the engine. The flow field that the rotors are immersed in may be higher than the free stream flow and it may not be uniform, both of these characteristics could increase noise and decrease performance. The rotors sometimes cause changes in the flow conditions imposed on aircraft surfaces. At high power conditions such as takeoff and climb out, the stream tube of air that goes through the rotors contracts rapidly causing the boundary layer on the body upper surface to go through an adverse pressure gradient which could result with separated airflow. The BWB / Open Rotor configuration must be designed to mitigate these problems

    Comparison of Protein- or Amino Acid-Based Supplements in the Rehabilitation of Men with Severe Obesity: A Randomized Controlled Pilot Study

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    Background: Weight loss is associated with a reduction in all body compartments, including muscle mass (MM), and this effect produces a decrease in function and muscle strength. Our objective was to assess the impact of protein or amino acid supplements on MM loss in middle-aged men (age 35 kg/m2) during weight loss. Materials and Methods: We conducted a single-site randomized controlled trial (Clinicaltrials.gov NCT05143398) with 40 in-patient male subjects with severe obesity. Participants underwent an intervention program consisting of a low-calorie balanced diet and structured physical activity. They were randomly assigned to 4-week treatment groups: (1) control (CTR, N = 10), (2) protein (P, N = 10), (3) branched-chain amino acid (BCAA, N = 10), and (4) essential amino acid mixture with tricarboxylic acid cycle intermediates (PD-E07, N = 10) supplementation. Results: Following 4 weeks of intervention, all groups showed similar reductions in body weight compared to baseline. When examining the delta values, a notable increase in muscle mass (MM) was observed in the PD-E07 intervention group [MM (kg): 2.84 ± 3.57; MM (%): 3.63 ± 3.14], in contrast to the CTR group [MM (kg): −2.46 ± 3.04; MM (%): −0.47 ± 2.28], with a statistical significance of p = 0.045 and p = 0.023, respectively. However, the MM values for the P group [MM (kg): −2.75 ± 5.98, p = 0.734; MM (%): −0.44 ± 4.02, p = 0.990] and the BCAA group [MM (kg): −1 ± 3.3, p = 0.734; MM (%): 0.34 ± 2.85, p = 0.956] did not exhibit a statistically significant difference when compared to the CTR group. Conclusions: Amino acid-based supplements may effectively mitigate the loss of MM typically observed during weight reduction. Further validation through large-scale studies is necessary

    Produksi Minuman Kesehatan Teh Uirame di Kampung Koya Tengah, Distrik Muara Tami, Jayapura

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    Koya Tengah is one of the villages in Muara Tami District, Jayapura City. KKN organized by Faculty of Mathematics and Natural Sciences, Cenderawasih University took the theme “Papua Tangguh”. Which aims to contribute to build Papuan community into a resilient community in the health sector. KKN participants provide program about the benefits of spices that are around that can be used to make herbal product “Uirame Tea” that are useful for increase body immunity. Uirame Tea is made from a mixture of various herbal plants from leaves, twigs, and wood shavings. Herbal plants with many benefits can be processed into a health food or beverage product such as Uirame Tea which needs to be developed because the composition come from spices with antioxidant content. Therefore, in the implementation of Thematic KKN Papua Tangguh, there will be socialization about the benefits and ways of making Uirame Tea to the community, with the aim of understanding the efficacy of uirame tea spice ingredients and knowing how to make Uirame Tea traditionally. This program is carried out for 21 days starting from August 16 to September 5, 2021.Keyword: Uirame tea; Koya Tengah village; Papua

    Spatial memory and cognitive flexibility trade-offs : to be or not to be flexible, that is the question

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    All authors were supported by National Science Foundation (NSF) grant IOS1351295 to V.V.P., and C.L.B. was supported by NSF grant DDIG 1600845.Cognitive flexibility allows animals to readily acquire new information even when learning contingencies may rapidly change, as is the case in highly variable, but predictable, environments. While cognitive flexibility is broadly thought to be beneficial, animals exhibit inter- and intraspecific variation, with higher levels of flexibility associated with reduced memory retention and vice versa. In this review, we discuss when and why such variation may exist and focus specifically on memory and memory flexibility. We argue that retained memories may negatively affect the acquisition of new information, most likely via proactive interference, and available data suggest that there may be a trade-off between memory retention and acquiring new memories. We discuss neurogenesis-mediated forgetting as the mechanism reducing memory interference, as new neurons enhance learning new information but also cause forgetting of older memories. Selection may be expected to favour either end of the continuum between memory retention and memory flexibility depending on life history and environment. More stable environments may favour memory retention over flexibility whereas rapidly changing environments may favour flexibility over retention. Higher memory capacity also seems to be associated with higher memory interference, so higher neurogenesis rates associated with forgetting of unnecessary information may be favoured when higher capacity is beneficial such as in food-caching species. More research is necessary to understand whether inter- and intraspecific differences in the association between memory retention and flexibility are related to some general ecological patterns, whether this association is heritable, and whether developmental conditions and experience have different effects on this association in different species.PostprintPeer reviewe

    Four small puzzles that Rosetta doesn't solve

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    A complete macromolecule modeling package must be able to solve the simplest structure prediction problems. Despite recent successes in high resolution structure modeling and design, the Rosetta software suite fares poorly on deceptively small protein and RNA puzzles, some as small as four residues. To illustrate these problems, this manuscript presents extensive Rosetta results for four well-defined test cases: the 20-residue mini-protein Trp cage, an even smaller disulfide-stabilized conotoxin, the reactive loop of a serine protease inhibitor, and a UUCG RNA tetraloop. In contrast to previous Rosetta studies, several lines of evidence indicate that conformational sampling is not the major bottleneck in modeling these small systems. Instead, approximations and omissions in the Rosetta all-atom energy function currently preclude discriminating experimentally observed conformations from de novo models at atomic resolution. These molecular "puzzles" should serve as useful model systems for developers wishing to make foundational improvements to this powerful modeling suite.Comment: Published in PLoS One as a manuscript for the RosettaCon 2010 Special Collectio

    Increasing diterpene yield with a modular metabolic engineering system in E. coli: comparison of MEV and MEP isoprenoid precursor pathway engineering

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    Engineering biosynthetic pathways in heterologous microbial host organisms offers an elegant approach to pathway elucidation via the incorporation of putative biosynthetic enzymes and characterization of resulting novel metabolites. Our previous work in Escherichia coli demonstrated the feasibility of a facile modular approach to engineering the production of labdane-related diterpene (20 carbon) natural products. However, yield was limited (<0.1 mg/L), presumably due to reliance on endogenous production of the isoprenoid precursors dimethylallyl diphosphate and isopentenyl diphosphate. Here, we report incorporation of either a heterologous mevalonate pathway (MEV) or enhancement of the endogenous methyl erythritol phosphate pathway (MEP) with our modular metabolic engineering system. With MEP pathway enhancement, it was found that pyruvate supplementation of rich media and simultaneous overexpression of three genes (idi, dxs, and dxr) resulted in the greatest increase in diterpene yield, indicating distributed metabolic control within this pathway. Incorporation of a heterologous MEV pathway in bioreactor grown cultures resulted in significantly higher yields than MEP pathway enhancement. We have established suitable growth conditions for diterpene production levels ranging from 10 to >100 mg/L of E. coli culture. These amounts are sufficient for nuclear magnetic resonance analyses, enabling characterization of enzymatic products and hence, pathway elucidation. Furthermore, these results represent an up to >1,000-fold improvement in diterpene production from our facile, modular platform, with MEP pathway enhancement offering a cost effective alternative with reasonable yield. Finally, we reiterate here that this modular approach is expandable and should be easily adaptable to the production of any terpenoid natural product
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