Determination of cellular strains by combined atomic force microscopy and finite element modeling

Many organs adapt to their mechanical environment as a result of physiological change or disease. Cells are both the detectors and effectors of this process. Though many studies have been performed in vitro to investigate the mechanisms of detection and adaptation to mechanical strains, the cellular strains remain unknown and results from different stimulation techniques cannot be compared. By combining experimental determination of cell profiles and elasticities by atomic force microscopy with finite element modeling and computational fluid dynamics, we report the cellular strain distributions exerted by common whole-cell straining techniques and from micromanipulation techniques, hence enabling their comparison. Using data from our own analyses and experiments performed by others, we examine the threshold of activation for different signal transduction processes and the strain components that they may detect. We show that modulating cell elasticity, by increasing the F-actin content of the cytoskeleton, or cellular Poisson ratio are good strategies to resist fluid shear or hydrostatic pressure. We report that stray fluid flow in some substrate-stretch systems elicits significant cellular strains. In conclusion, this technique shows promise in furthering our understanding of the interplay among mechanical forces, strain detection, gene expression, and cellular adaptation in physiology and disease

A Generalized Approach for Automated Compressor Performance Mapping Using Artificial Neural Network

In the last decades, several research and development efforts led to new compressor technologies that have been successfully introduced into market such as hermetic compressors with variable-speed motors, compressors with economization lines (both vapor and liquid injection lines), hermetic linear compressors, novel capacity modulations, and oil-flooding among others. During the process of implementing new compressor technologies, performance mapping is essential to predict the system behavior across different operating conditions. However, current standard AHRI-540 for compressor performance rating utilizes a 10-coefficient polynomial model that has severe limitations to include compressor enhancement technologies and variable operating range. In addition, it is common practice in industry to calibrate such polynomial correlations with at least 15 to 20 compressor calorimeter test points for a single compressor to ensure a good fit, which results in extended laboratory testing time and relatively high associated costs. Therefore, an automated compressor performance mapping approach based on artificial neural network (ANN) modeling is proposed to address and overcome the limitations of the current standard including applicability to any positive displacement compressors and minimization of number of test points required to accurately predict the compressor envelope. In this paper, the performance of a positive displacement compressor is mapped by this novel methodology, which relies on an algorithm that effectively determines the minimum set of data points required and optimizes the training/testing of ANN architecture. The accuracy and reliability of the proposed methodology are compared to the conventional 10-coefficient polynomial mapping. Lastly, the propagated uncertainties through the model and its extrapolation capabilities are also analyzed

Boston Hospitality Review: Spring 2016

Understanding the Momentum and Motivations of Foreign Investors in U.S. Hospitality by Ken Wilson and Liya Ma -- Creating Memorable Experiences: How hotels can fight back against Airbnb and other sharing economy providers by Makarand Mody -- Rebranding Before the Digital Age: 4 Strategies Used by the Sheraton New York Hotel and Towers During the 1992 Democratic National Convention by Leora Halpern Lanz, Juan Lesmes, and Erinn Tucker -- Federal Minimum Wage Debate: Are Gubernatorial Politics Behind a Hotel Line Employee Wage? by Nicholas Thomas and Eric Brown -- Rethinking Substance Use and Abuse Among Hospitality Employees by Amir Shani -- Consumers’ Desires in Hostels: Addressing Latent and Explicit Needs in United States Hostels by Emily Horto

Heat-Pump Control Design Performance Evaluation using Load-Based Testing

Space heating is one of the primary components of residential energy usage in the U.S., accounting for nearly 43% (EIA, 2015) of the total residential energy consumption. To reduce this energy usage, heat-pumps provide an energy-efficient alternative to currently prevalent systems such as electric heaters and gas furnaces. Advanced control strategies have the potential to further improve heat-pump system energy efficiency and comfort delivery. In recent years, advancements in the microprocessor field have made it possible to widely implement advanced energy-efficient controls within heat-pump systems. However, still only a very small fraction of residential air-conditioners and heat-pumps currently sold in the U.S. market utilize these next-generation controls (ACEEE, 2019). To facilitate an acceleration in the development and implementation of advanced control architectures within heat-pump equipment, a load-based testing methodology can be utilized. Load-based testing allows realistic dynamic behavior and performance evaluation of energy efficiency and comfort delivery for heat pumping and air conditioning equipment with embedded controls in a laboratory setting. In the load-based testing methodology, the sensible and latent loads of a representative residential building are emulated in the indoor psychrometric test room by dynamically varying the test room conditions utilizing a virtual building model. The test equipment responds dynamically to this virtual building with its embedded controls based on the thermostat sensing response. This enables engineers to evaluate the performance of a heat-pump in a controlled setting under dynamic conditions that are similar to a field application but with a significant reduction in testing time and cost. This paper demonstrates the application of load-based testing for evaluating the performance of a 5-ton split-type residential heat-pump with its integrated controls in a heating mode application. Furthermore, the effect of equipment oversizing and undersizing on the heat-pump energy consumption and comfort delivery are also presented

Synthesis of new chiral organosulfur donors with hydrogen bonding functionality and their first charge transfer salts

The syntheses of a range of enantiopure organosulfur donors with hydrogen bonding groups are described including TTF related materials with two, four, six and eight hydroxyl groups and multiple stereogenic centres and a pair of chiral N-substituted BEDT-TTF acetamides. Three charge transfer salts of enantiopure poly-hydroxy-substituted donors are reported, including a 4:1 salt with the meso stereoisomer of the dinuclear [Fe2(oxalate)5 ]4- anion in which both cation and anion have chiral components linked together by hydrogen bonding, and a semiconducting salt with triiodide

Frost Formation in Evaporator Fins with Embedded Negative Stiffness Structures

Frosting in the evaporator leads to an increase in thermal resistance and reduced airflow, resulting in decreased performance. Traditional thermal defrosting strategies lead to significant energy penalties. Novel shape morphing evaporator fins embedded with multistable structures offer the opportunity for faster defrosting and large energy savings while keeping the capital cost low. This type of morphing fins enables a mechanical defrosting approach that is more effective for higher densities and thicknesses of frost. However, there is a need to better understand frost formation in these structures. In this study, we use a modeling and experimental approach to understand frosting on shape morphing fins. An experimental setup was developed that is capable of frost formation at different conditions and testing various defrosting strategies. Leveraging this, we formed frost at various conditions on both an angled shape morphing fin and a flat fin and performed comparisons between model predictions and measurements

The Three-Magnon Contribution to the Spin Correlation Function in Integer-Spin Antiferromagnetic Chains

The exact form factor for the O(3) non-linear sigma model is used to predict the three-magnon contribution to the spin correlation function, S(q,w), near wavevector q=pi in an integer spin, one-dimensional antiferromagnet. The three-magnon contribution is extrememly broad and extremely weak; the integrated intensity is <2% of the single-magnon contribution.Comment: 4 pages, 1 figur

A bioinformatics potpourri

© 2018 The Author(s). The 16th International Conference on Bioinformatics (InCoB) was held at Tsinghua University, Shenzhen from September 20 to 22, 2017. The annual conference of the Asia-Pacific Bioinformatics Network featured six keynotes, two invited talks, a panel discussion on big data driven bioinformatics and precision medicine, and 66 oral presentations of accepted research articles or posters. Fifty-seven articles comprising a topic assortment of algorithms, biomolecular networks, cancer and disease informatics, drug-target interactions and drug efficacy, gene regulation and expression, imaging, immunoinformatics, metagenomics, next generation sequencing for genomics and transcriptomics, ontologies, post-translational modification, and structural bioinformatics are the subject of this editorial for the InCoB2017 supplement issues in BMC Genomics, BMC Bioinformatics, BMC Systems Biology and BMC Medical Genomics. New Delhi will be the location of InCoB2018, scheduled for September 26-28, 2018

Adult Learners: A Targeted Marketing Approach

The development of the Adult Learner Capstone Project started with a focus and need to learn more about affinity groups in the Worcester area in order to reach the potential adult learner demographic. Although some partnerships already existed, the Director of Marketing and Communications for Graduate Admissions, Tara Probeck, yearned to explore the potential partnerships and alternative uses of professional organizations to market to the current working professionals. From this idea, our capstone project was introduced in hopes of establishing a comprehensive and exhaustive list of potential organizational partnerships, specific for the School of Professional Studies