Pattern formation in Faraday instability-experimental validation of theoretical models

Two types of resonance-derived interfacial instability are reviewed with a focus on recent work detailing the effect of side walls on interfacial mode discretization. The first type of resonance is the mechanical Faraday instability, and the second is electrostatic Faraday instability. Both types of resonance are discussed for the case of single-frequency forcing. In the case of mechanical Faraday instability, inviscid theory can forecast the modal forms that one might expect when viscosity is taken into account. Experiments show very favourable validation with theory for both modal forms and onset conditions. Lowering of gravity is predicted to shift smaller wavelengths or choppier modes to lower frequencies. This is also validated by experiments. Electrostatic resonant instability is shown to lead to a pillaring mode that occurs at low wavenumbers, which is akin to Rayleigh Taylor instability. As in the case of mechanical resonance, experiments show favourable validation with theoretical predictions of patterns. A stark difference between the two forms of resonance is the observation of a gradual rise in the negative detuning instability in the case of mechanical Faraday and a very sharp one in the case of electrostatic resonance. This article is part of the theme issue 'New trends in pattern formation and nonlinear dynamics of extended systems'.

Technological advancements in jaggery-making processes and emission reduction potential via clean combustion for sustainable jaggery production: An overview

Jaggery is a kind of unrefined non-centrifugal sugar (NCS) used mainly in Asia, Africa, Latin America, and the Caribbean. Traditionally, jaggery is produced by concentrating sugarcane juice in open pans with the help of bagasse combustion. However, due to thermal energy loss with flue gases and an unscientific approach in plant construction, jaggery plants have a poor thermal efficiency of less than 25%, poor emission characteristics, and a high bagasse consumption rate. Advanced jaggery-making techniques use solar energy and heat pumps for jaggery production. However, these techniques are in the early stage of development, and the literature indicates that these techniques should be used in conjuction with traditional ones to improve the performance of jaggery making plants. This literature review describes advances in jaggery-making methods, critically analyzed them, and provides a qualitative comparison of these methods. Further, gaps in the existing literature are identified and reported for future research direction. In addition, efforts have been made to quantify and estimate the emissions reduction and bagasse consumption potentials from the traditional jaggery industry to make this rural industry a sustainable and profitable business for rural entrepreneurs. The comparison with the recently developed clean combustion device exhibits that the harmful emissions from the jaggery industry could be reduced drastically viz. 95%-98% of PM2.5; 92%-95% of CO, and 52-60% of CO2, while saving more than 35% of bagasse consumption. Implemented at a national scale, it may reduce nearly 3% of all harmful emissions in the country, which is equally applicable elsewhere.

A comprehensive review of the recent development and challenges of a solar-assisted biodigester system

The extensive use of fossil fuels and the environmental effect of their combustion products have attracted researchers to look into renewable energy sources. In addition, global mass production of waste has motivated communities to recycle and reuse the waste in a sustainable way to lower landfill waste and associated problems. The development of waste to energy (WtE) technology including the production of bioenergy, e.g. biogas produced from various waste through Anaerobic Digestion (AD), is considered one of the potential measures to achieve the sustainable development goals of the United Nations (UN). Therefore, this study reviews the most recent studies from relevant academic literature on WtE technology (particularly AD technology) for biogas production and the application of a solar-assisted biodigester (SAB) system aimed at improving performance. In addition, socio-economic factors, challenges, and perspectives have been reported. From the analysis of different technologies, further work on effective low-cost technologies is recommended, especially using SAB system upgrading and leveraging the opportunities of this system. The study found that the performance of the AD system is affected by a variety of factors and that different approaches can be applied to improve performance. It has also been found that solar energy systems efficiently raise the biogas digester temperature and through this, they maximize the biogas yield under optimum conditions. The study revealed that the solar-assisted AD system produces less pollution and improves performance compared to the conventional AD system.

Effect of spinning on the shape and stability of a pendent drop

Assuming that we wish to measure the surface tension between two liquids by running a pendent drop experiment, we present calculations supporting the case for spinning the drop. For bridges, jets, etc., spinning a heavy fluid surrounded by a lighter fluid is strictly destabilizing. But we find that spinning a drop may be stabilizing and, if this is so, it leads to larger critical volumes, volumes where stability is lost, and thus more accurate measurements of surface tension. There are two observable patterns, one symmetric and the other unsymmetric, at the point of instability. The symmetric pattern leads to larger critical volumes. Our aim is to show how spinning can be used to achieve the symmetric pattern.

Bowel Migration of Dormant Chronic Ambulatory Peritoneal Dialysis Catheter: A Vexed Problem Not Avoided by Flushing

Delayed bowel erosion by peritoneal dialysis catheter is rare with fewer than thirty cases having been reported in the literature. This complication is usually encountered when the catheter is kept dormant. Two cases have also been reported with catheters in active use. The risk factors for bowel erosion include immunosuppression, diverticulosis, and amyloidosis. An 80-year-old male with chronic kidney disease Stage 5 due to hypertensive nephrosclerosis underwent chronic ambulatory peritoneal dialysis catheter insertion. Due to improvement in the glomerular filtration rate and clinical parameters including extracellular fluid volume status, peritoneal dialysis was not initiated. Weekly catheter flushes were performed. After 5 months, he developed watery diarrhea after a regular flushing episode. Computed tomography scan revealed the catheter displaced into the sigmoid colon with the tip in the rectum. He was managed successfully with catheter removal alone and conservative treatment. He remains asymptomatic at 3-month follow-up. This case is presented to emphasize the fact that delayed bowel erosion can happen with dormant catheter even in the absence of risk factors. Periodic flushing has not prevented this complication in our patient. Perforations can be self-curing when diagnosed early and when patients present without features of peritonitis or sepsis. Such cases can be managed successfully with catheter removal alone.

Dimensionality-Dependent Electrochemical Kinetics at the Single-Layer Graphene-Electrolyte Interface

The theories to describe the rate at which electrochemical reactions proceed, to date, do not consider explicitly the dimensionality or the discreteness and occupancy of the energy levels of the electrodes. We show experimentally that such quantum mechanical aspects are important for dimensionally confined nanostructured materials and yield unusual variation of the kinetic rate constants with applied voltage in single-layer graphene. The observed divergence from conventional electrokinetics was ascribed to the linear energy dispersion as well as a nonzero density of states at the Dirac point in the graphene. The obtained results justify the use of density of states-based rate constants and considerably add to Marcus-Hush-Chidsey kinetics.

Endurance based personalized fitness planner

Endurance is an important factor of cardiovascular fitness indicating the capacity of an individual to perform exercise for a longer duration with increased intensity. Various subject specific and exercise related parameters affect endurance of an individual. In this work, we propose a statistical technique to model endurance as a function of these factors incorporating the serial dependence of observations generated by individuals over time. The proposed model provides a device to predict future endurance of a test subject following particular exercise regime. This facilitates a test user with a fitness planner with the provision to fix exercise regimes to reach a set fitness goal.

Cholecystokinin-2/gastrin antagonists: 5-hydroxy-5-aryl-pyrrol-2-ones as anti-inflammatory analgesics for the treatment of inflammatory bowel disease

Arylated 5-hydroxy-pyrrol-2-ones were prepared in 2 synthetic steps from mucochloric acid and optimised as CCK2-selective ligands using radiolabelled binding assays. CCK antagonism was confirmed for the ligands in isolated tissue preparations. DSS (dextran sulfate sodium)-induced inflammation was analysed for derivative 7 and PNB-001 with L-365,260 as a standard. The IC50 of PNB-001 was determined to be 10 nM. Subsequent in vivo evaluation confirmed anti-inflammatory activity with respect to IBD assays. The best molecule, PNB-001, showed analgesic activity in the formalin test and in the hotplate assay, in which the analgesic effect of 1.5 mg kg-1 PNB-001 was equivalent to 40 mg kg-1 tramadol. The CCK2-selective antagonist PNB-001 protected rats against indomethacin-induced ulceration at similar doses. The GI protection activity was found to be more potent than that of the 10 mg kg-1 dose of prednisolone, which served as a standard.

Abstract P6-12-06: Nonsteroidal, tissue selective androgen receptor modulator (SARM), enobosarm, reduces growth of androgen receptor-positive breast cancer in patient-derived preclinical models

Introduction: In breast cancer the androgen receptor (AR) is the most abundantly expressed steroid receptor with 75-95% of estrogen receptor (ER)-positive and 40-70% of ER-negative breast cancers expressing the AR. Historically, advanced breast cancer has been treated with androgens, resulting in significant clinical response. However, the use of steroidal androgens fell from favor as a result of their virilizing side effects. Nonsteroidal, tissue selective androgen receptor modulators (SARMs) will provide a novel targeted approach to exploit the therapeutic benefits of androgens in breast cancer.

Aims: To test the effects of enobosarm (a first-in-class SARM) and enzalutamide (AR antagonist) on the growth of patient-derived breast cancer xenografts (PDX) and to discern the mechanism of action of AR-targeted therapies in AR-positive breast cancer.

Materials and Methods: AR-positive PDXs with varying receptor expression (ER, progesterone receptor (PR), and HER2) were implanted in immunecompromised mice. Mice carrying PDXs were treated with vehicle, 10 mg/kg/day (mpk) enobosarm (GTx, Inc., Memphis, TN), or 20 mpk enzalutamide (Medivation Inc.), orally. Tumor volume was measured twice or thrice weekly. Tumors that received enobosarm were further analyzed to determine the mechanism of action.

Results: Enobosarm significantly (p<0.01) inhibited the growth of ER-, PR-, and HER2- positive HCI-7 and ER- and PR- negative and HER2-positive HCI-12 PDX. While enobosarm inhibited the growth of HCI-12 by ~80% and HCI-7 by ~60%, enzalutamide failed to inhibit the growth of the HCI-7 PDX. In contrast, neither enobosarm nor enzalutamide inhibited the growth of ER- and PR-negative and HER2-positive HCI-9 PDX, consistent with the heterogeneity of AR-positive breast cancers. Growth of two triple-negative breast cancer (TNBC) PDXs were inhibited by 30-40% by enobosarm, but not by enzalutamide. These results were reproduced in xenografts developed with breast cancer cell lines, MCF-7 and MDA-MB-231 expressing the AR. Gene expression studies conducted with the HCI-12 tumors indicated that enobosarm inhibited the expression of various proliferative genes (MUC2, IL10RA, IGSF1, SLC6A4, and others) and increased the expression of growth inhibitory genes (CYP4F8, MYBPC1, and others). Ingenuity pathway analysis demonstrated that enobosarm inhibited genes that are downstream of HER2 signaling. Interestingly, miR-21-3p, which has been implicated in chemo-resistance, was consistently expressed at approximately 10-50-fold higher than miR-21-5p in PDXs. This imbalance was partially reversed by enobosarm.

Conclusion: These results indicate that AR-positive breast cancers are highly heterogeneous and that enobosarm has promise as novel targeted therapy to treat AR-positive breast cancer. Enobosarm is currently in phase II clinical trial in both ER-positive breast cancer and in TNBC patients.

Citation Format: Narayanan R, Ponnusamy S, Fan M, Yang CH, Grimes BL, Fleming MD, Pritchard EF, Berry MP, Oswaks RM, Fine RE, Loiseau J-C, Schwartzberg LS, Pfeffer LM. Nonsteroidal, tissue selective androgen receptor modulator (SARM), enobosarm, reduces growth of androgen receptor-positive breast cancer in patient-derived preclinical models [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P6-12-06.

An Investigation of the Variety and Complexity of Statistical Methods Used in Current Internal Medicine Literature

OBJECTIVES

Accreditation Council for Graduate Medical Education guidelines require internal medicine residents to develop skills in the interpretation of medical literature and to understand the principles of research. A necessary component is the ability to understand the statistical methods used and their results, material that is not an in-depth focus of most medical school curricula and residency programs. Given the breadth and depth of the current medical literature and an increasing emphasis on complex, sophisticated statistical analyses, the statistical foundation and education necessary for residents are uncertain.

METHODS

We reviewed the statistical methods and terms used in 49 articles discussed at the journal club in the Department of Internal Medicine residency program at Texas Tech University between January 1, 2013 and June 30, 2013. We collected information on the study type and on the statistical methods used for summarizing and comparing samples, determining the relations between independent variables and dependent variables, and estimating models. We then identified the typical statistics education level at which each term or method is learned.

RESULTS

A total of 14 articles came from the Journal of the American Medical Association Internal Medicine, 11 from the New England Journal of Medicine, 6 from the Annals of Internal Medicine, 5 from the Journal of the American Medical Association, and 13 from other journals. Twenty reported randomized controlled trials. Summary statistics included mean values (39 articles), category counts (38), and medians (28). Group comparisons were based on t tests (14 articles), χ2 tests (21), and nonparametric ranking tests (10). The relations between dependent and independent variables were analyzed with simple regression (6 articles), multivariate regression (11), and logistic regression (8). Nine studies reported odds ratios with 95% confidence intervals, and seven analyzed test performance using sensitivity and specificity calculations. These papers used 128 statistical terms and context-defined concepts, including some from data analysis (56), epidemiology-biostatistics (31), modeling (24), data collection (12), and meta-analysis (5). Ten different software programs were used in these articles. Based on usual undergraduate and graduate statistics curricula, 64.3% of the concepts and methods used in these papers required at least a master's degree-level statistics education.

CONCLUSIONS

The interpretation of the current medical literature can require an extensive background in statistical methods at an education level exceeding the material and resources provided to most medical students and residents. Given the complexity and time pressure of medical education, these deficiencies will be hard to correct, but this project can serve as a basis for developing a curriculum in study design and statistical methods needed by physicians-in-training.

Cholecystokinin-1 receptor antagonists: 5-hydroxy-5-aryl-pyrrol-2-ones as anticancer agents

Hydroxy-pyrrolones, which were potent CCK1R antagonists, showed nanomolar in vitro activity and anticancer activity in vivo for colon and pancreatic cancer.

Modulation of the Electrostatic and Quantum Capacitances of Few Layered Graphenes through Plasma Processing

It is shown that charged defect generation, through argon ion-based plasma processing, in few layer graphene, could substantially enhance the electrical capacitance for electrochemical energy storage. Detailed consideration of the constituent space charge and quantum capacitances were used to delineate a new length scale, correlated to electrically active defects contributing to the capacitance, and was found to be smaller than a structural correlation length determined through Raman spectroscopy. The study offers insights into an industrially viable method (i.e., plasma processing) for modifying and enhancing the energy density of graphene-based electrochemical capacitors.

Density of states in graphene with vacancies: midgap power law and frozen multifractality

The density of states ϱ(E) of graphene is investigated numerically and within the self-consistent T-matrix approximation in the presence of vacancies within the tight binding model. The focus is on compensated disorder, where the concentration of vacancies n(A) and n(B) in both sublattices is the same. Formally, this model belongs to the chiral symmetry class BDI. The onlinear sigma model predicts for BDI a Gade-type singularity ϱ(E)∼|E|(-1)exp[-|log(E)|(-1/x)]. Our numerical data are comparable to this result in a preasymptotic regime that gives way, however, at even lower energies to ϱ(E)∼E(-1)|log(E)|(-x̃), 1≤x̃<2. We take this finding as evidence that, similar to the case of dirty d-wave superconductors, generic bipartite random hopping models may also exhibit unconventional (strong-coupling) fixed points for certain kinds of randomly placed scatterers if these are strong enough. Our research suggests that graphene with (effective) vacancy disorder is a physical representative of such systems.

Abstract P5-09-21: Selective androgen receptor modulators (SARMs): Enobosarm as targeted therapy for the treatment of androgen receptor-positive breast cancer

Background: The androgen receptor (AR) is the most highly expressed steroid receptor in breast cancer with 75-95% of estrogen receptor (ER)-positive and 40-70% of ER-negative breast cancers expressing AR. Prior studies have shown that women with metastatic breast cancer who have been previously treated with tamoxifen and progress have responded to non-tissue-selective androgens like fluoxymesterone, medroxyprogesterone and danazol, with overall response rates ranging from 20 to 60%. Although these non-tissue-selective androgens have been used to treat breast cancer, the unwanted virilizing side effects, including facial and body hair, enlargement of voice box, acne, and edema, have limited their widespread clinical use. Nonsteroidal, tissue- selective androgen receptor modulators (SARMs) like enobosarm and GTx-027 may provide a novel targeted approach to exploit the therapeutic benefits of androgen therapy in breast cancer without the unwanted virilizing side effects or concerns related to their conversion by aromatase to estrogens.

Methods: MDA-MB-231 triple-negative and MCF-7 triple-positive breast cancer cells stably expressing AR (MDA-MB-231-AR and MCF-7-AR, respectively) were used to evaluate the in vitro and in vivo anti-proliferative and gene expression effects of bicalutamide (an AR antagonist), dihydrotestosterone (DHT), enobosarm, and GTx-027. Phase II clinical studies examined the pharmacologic effects (lean body mass and muscle strength), tissue selectivity (skin, endometrium, and hair growth) and safety of enobosarm, a first-in-class SARM, in postmenopausal women.

Results: DHT and SARMs, but not bicalutamide, inhibited the proliferation of MDA-MB-231-AR and MCF-7-AR cells. DHT and the SARMs functioned as AR agonists in transactivation assays in MDA-MB-231 cells, indicating that AR agonists, but not antagonists, elicit anti-proliferative effects in breast cancer. MDA-MB-231-AR and MCF-7-AR cells were implanted subcutaneously in nude mice and were treated orally with vehicle or 30 mg/kg/day GTx-027. GTx-027 reduced the tumor growth significantly with greater than 75% tumor growth inhibition observed in MDA-MB-231-AR tumors and greater than 50% tumor growth inhibition observed in MCF-7-AR tumors, compared to vehicle-treated tumors. GTx-027 also inhibited tumor weights by greater than 50% concurring with the tumor volume observation. GTx-027 inhibited the intratumoral expression of genes and pathways that promote breast cancer development through its actions on the AR. Interestingly, GTx-027 and other AR agonists elicited opposite effects on various AR target genes in ER-positive versus ER-negative breast cancer cells, indicating a potential cross talk between AR and ER signaling pathways on the promoter of these genes. Phase II clinical studies showed that enobosarm was generally well tolerated in postmenopausal women. Statistically significant improvements in lean body mass and physical function were observed after 12 weeks of treatment with 3 mg enobosarm, with no significant changes in sebaceous gland volume (biopsy), hair growth, endometrial stripe thickness (transvaginal ultrasound) or bleeding (medroxyprogesterone challenge).

Dual role of gravity on the Faraday threshold for immiscible viscous layers

This work discusses the role of gravity on the Faraday instability, and the differences one can expect to observe in a low-gravity experiment when compared to an earth-based system. These differences are discussed in the context of the viscous linear theory for laterally infinite systems, and a surprising result of the analysis is the existence of a crossover frequency where an interface in low gravity switches from being less to more stable than an earth-based system. We propose this crossover exists in all Faraday systems, and the frequency at which it occurs is shown to be strongly influenced by layer height. In presenting these results physical explanations are provided for the behavior of the predicted forcing amplitude thresholds and wave number selection.