Piezoelectric-based apparatus for strain tuning

We report the design and construction of piezoelectric-based apparatus for applying continuously tuneable compressive and tensile strains to test samples. It can be used across a wide temperature range, including cryogenic temperatures. The achievable strain is large, so far up to 0.23% at cryogenic temperatures. The apparatus is compact and compatible with a wide variety of experimental probes. In addition, we present a method for mounting high-aspect-ratio samples in order to achieve high strain homogeneity.Comment: 8 pages, 8 figure

Assessment of potential anti-cancer stem cell activity of marine algal compounds using an in vitro mammosphere assay

Background: The cancer stem cell (CSC) theory proposes that tumours arise from and are sustained by a subpopulation of cells with both cancer and stem cell properties. One of the key hallmarks of CSCs is the ability to grow anchorage-independently under serum-free culture conditions resulting in the formation of tumourspheres. It has further been reported that these cells are resistant to traditional chemotherapeutic agents. Methods: In this study, the tumoursphere assay was validated in MCF-7 cells and used to screen novel marine algal compounds for potential anti-cancer stem cell (CSC) activity in vitro. Results: MCF-7 breast cancer cells were observed to generate tumourspheres or mammospheres after 3-5 days growth in anchorage-independent conditions and an apparent enrichment in potential CSCs was observed by an increase in the proportion of CD44high/CD24low marker-bearing cells and Oct4 expression compared to those in the bulk population grown in regular adherent conditions. Using this assay, a set of algal metabolites was screened for the ability to inhibit mammosphere development as a measure of potential anti-CSC activity. We report that the polyhalogenated monoterpene stereoisomers RU017 and RU018 isolated from the red alga Plocamium cornutum, both of which displayed no cytotoxicity against either adherent MCF-7 breast cancer or MCF-12A non-transformed breast epithelial cells, were able to prevent MCF-7 mammosphere formation in vitro. On the other hand, neither the brown algal carotenoid fucoxanthin nor the chemotherapeutic paclitaxel, both of which were toxic to adherent MCF-7 and MCF-12A cells, were able to inhibit mammosphere formation. In fact, pre-treatment with paclitaxel appeared to enhance mammosphere formation and development, a finding which is consistent with the reported resistance of CSCs to traditional chemotherapeutic agents. Conclusion: Due to the proposed clinical significance of CSC in terms of tumour initiation and metastasis, the identification of agents able to inhibit this subpopulation has clinical significance

Commensurate 4a04a_0 period Charge Density Modulations throughout the Bi2Sr2CaCu2O8+xBi_2Sr_2CaCu_2O_{8+x} Pseudogap Regime

Theories based upon strong real space (r-space) electron electron interactions have long predicted that unidirectional charge density modulations (CDM) with four unit cell (4$a_0$) periodicity should occur in the hole doped cuprate Mott insulator (MI). Experimentally, however, increasing the hole density p is reported to cause the conventionally defined wavevector $Q_A$ of the CDM to evolve continuously as if driven primarily by momentum space (k-space) effects. Here we introduce phase resolved electronic structure visualization for determination of the cuprate CDM wavevector. Remarkably, this new technique reveals a virtually doping independent locking of the local CDM wavevector at $|Q_0|=2\pi/4a_0$ throughout the underdoped phase diagram of the canonical cuprate $Bi_2Sr_2CaCu_2O_8$. These observations have significant fundamental consequences because they are orthogonal to a k-space (Fermi surface) based picture of the cuprate CDM but are consistent with strong coupling r-space based theories. Our findings imply that it is the latter that provide the intrinsic organizational principle for the cuprate CDM state

Machine Learning in Electronic Quantum Matter Imaging Experiments

Essentials of the scientific discovery process have remained largely unchanged for centuries: systematic human observation of natural phenomena is used to form hypotheses that, when validated through experimentation, are generalized into established scientific theory. Today, however, we face major challenges because automated instrumentation and large-scale data acquisition are generating data sets of such volume and complexity as to defy human analysis. Radically different scientific approaches are needed, with machine learning (ML) showing great promise, not least for materials science research. Hence, given recent advances in ML analysis of synthetic data representing electronic quantum matter (EQM), the next challenge is for ML to engage equivalently with experimental data. For example, atomic-scale visualization of EQM yields arrays of complex electronic structure images, that frequently elude effective analyses. Here we report development and training of an array of artificial neural networks (ANN) designed to recognize different types of hypothesized order hidden in EQM image-arrays. These ANNs are used to analyze an experimentally-derived EQM image archive from carrier-doped cuprate Mott insulators. Throughout these noisy and complex data, the ANNs discover the existence of a lattice-commensurate, four-unit-cell periodic, translational-symmetry-breaking EQM state. Further, the ANNs find these phenomena to be unidirectional, revealing a coincident nematic EQM state. Strong-coupling theories of electronic liquid crystals are congruent with all these observations.Comment: 44 pages, 15 figure

Acoustically treated ground test nacelle for the General Electric TF34 turbofan

A description is given of the ground test quiet nacelle for the TF34 engine. The suppression treatment consists of cylindrical splitters in the inlet and fan exhaust ducts plus duct wall treatment and core exhaust wall treatment. Aerodynamic design analysis of the inlet and exhaust ducts and overall engine performance with pressure losses from the acoustic treatment is included. The objectives of the test program are to obtain noise data for a heavily suppressed high bypass turbofan with various arrangements of exhaust systems and acoustic treatment, and to provide a basis for the power plants of the Quiet Experimental STOL Aircraft (Questol)

Evaluating the Due Process and Crime Control Perspectives Using Rasch Measurement Analysis

Background:  The biases jurors possess may influence everything from the interpretation of case evidence to impressions of the defendant to, ultimately, verdict and recognition of this has led to a number of juror attitude scales attempting to tap into important biases.  A common ideology discussed in legal research is that individuals attitudes toward the law and the legal system differ along a continuum moving from due process (a concern for the preservation of individual rights) to crime control (a focus on swift and harsh punishment for those who break the law) although an agreed upon assessment of these perspectives has yet to be created.  Purpose:  The current research addresses due process and crime control perspectives and uses the ideology as a source for a new measure of juror bias: The General Attitudes toward the Legal System (GALS) scale. Setting:  Not applicable. Intervention:  Not applicable. Research Design: The GALS scale was constructed based on existing theory and administered to nearly 700 undergraduate psychology students at a large Midwestern university. The psychometric properties of the instrument were then evaluated to determine instrument quality.  Data Collection and Analysis:  The Rasch Rating Scale Model (RRSM) was used to evaluate the psychometric properties of the GALS. Evaluation focused on six characteristics of the instrument: dimensionality, reliability, rating scale quality, item quality, item hierarchy, and measure quality. Findings:  Results indicate the GALS is a psychometrically sound instrument for measuring juror bias. Keywords: juror decision making; juror bias; scale development; instrument validation; psychometric evaluatio

Evaluating the Due Process and Crime Control Perspectives Using Rasch Measurement Analysis

Background: The biases jurors possess may influence everything from the interpretation of case evidence to impressions of the defendant to, ultimately, verdict and recognition of this has led to a number of juror attitude scales attempting to tap into important biases. A common ideology discussed in legal research is that individuals attitudes toward the law and the legal system differ along a continuum moving from due process (a concern for the preservation of individual rights) to crime control (a focus on swift and harsh punishment for those who break the law) although an agreed upon assessment of these perspectives has yet to be created. Purpose: The current research addresses due process and crime control perspectives and uses the ideology as a source for a new measure of juror bias: The General Attitudes toward the Legal System (GALS) scale. Setting: Not applicable. Intervention: Not applicable. Research Design: The GALS scale was constructed based on existing theory and administered to nearly 700 undergraduate psychology students at a large Midwestern university. The psychometric properties of the instrument were then evaluated to determine instrument quality. Data Collection and Analysis: The Rasch Rating Scale Model (RRSM) was used to evaluate the psychometric properties of the GALS. Evaluation focused on six characteristics of the instrument: dimensionality, reliability, rating scale quality, item quality, item hierarchy, and measure quality. Findings: Results indicate the GALS is a psychometrically sound instrument for measuring juror bias