Stability of a Fully Magnetized Ferromagnetic state in Repulsively Interacting Ultracold Fermi Gases

We construct a variational wave function to study whether a fully polarized Fermi sea is energetically stable against a single spin flip. Our variational wave function contains sufficient short-range correlation at least to the same level as Gutzwiller's projected wave function. For Hubbard lattice model and continuum model with pure repulsive interaction, we show a fully polarized Fermi sea is generally unstable even when the repulsive strength becomes infinite. While for a resonance model, ferromagnetic state is possible if the s-wave scattering length is positive and sufficiently large, and the system is prepared in scattering state orthogonal to molecular bound state. However, we can not rule out the possibility that more exotic correlation can destabilize the ferromagnetic state.Comment: 4 pages, 3 figure

Estrogenic chemicals often leach from BPA-free plastic products that are replacements for BPA-containing polycarbonate products

Background: Xenobiotic chemicals with estrogenic activity (EA), such as bisphenol A (BPA), have been reported to have potential adverse health effects in mammals, including humans, especially in fetal and infant stages. Concerns about safety have caused many manufacturers to use alternatives to polycarbonate (PC) resins to make hard and clear, reusable, plastic products that do not leach BPA. However, no study has focused on whether such BPA-free PC-replacement products, chosen for their perceived higher safety, especially for babies, also release other chemicals that have EA. Methods: We used two, well-established, mammalian cell-based, assays (MCF-7 and BG1Luc) to assess the EA of chemicals that leached into over 1000 saline or ethanol extracts of 50 unstressed or stressed (autoclaving, microwaving, and UV radiation) BPA-free PC-replacement products. An EA antagonist, ICI 182,780, was used to confirm that agonist activity in leachates was due to chemicals that activated the mammalian estrogen receptor. Results: Many unstressed and stressed, PC-replacement-products made from acrylic, polystyrene, polyethersulfone, and Tritan™ resins leached chemicals with EA, including products made for use by babies. Exposure to various forms of UV radiation often increased the leaching of chemicals with EA. In contrast, some BPA-free PC-replacement products made from glycol-modified polyethylene terephthalate or cyclic olefin polymer or co-polymer resins did not release chemicals with detectable EA under any conditions tested. Conclusions: This hazard assessment survey showed that many BPA-free PC- replacement products still leached chemicals having significant levels of EA, as did BPA-containing PC counterparts they were meant to replace. That is, BPA-free did not mean EA-free. However, this study also showed that some PC-replacement products did not leach chemicals having significant levels of EA. That is, EA-free PC-replacement products could be made in commercial quantities at prices that compete with PC-replacement products that were not BPA-free. Since plastic products often have advantages (price, weight, shatter-resistance, etc.) compared to other materials such as steel or glass, it is not necessary to forgo those advantages to avoid release into foodstuffs or the environment of chemicals having EA that may have potential adverse effects on our health or the health of future generations.This work was supported by the following NIH/NIEHS grants: R44 ES011469, 01–03 (CZY); 1R43/44 ES014806, 01–03 (CZY); subcontract (CZY, PI) on an NIH Grant 01–03 43/44ES018083-01 to PlastiPure (DK, SY PIs).Neuroscienc

Preliminary design study of hydrogen and ammonia resistojets for prime and auxiliary thrusters

Designs of high performance resistojets for primary and auxiliary propulsion are described.Thruster power for the primary propulsion application was in the 2 to 3 kW range while auxiliary propulsion power per thruster was 0.15 to 0.25 kW. Propellants considered were hydrogen and ammonia. The report described design techniques used to forecast the temperature and energy flux distributions using mathematical modeling by personal microcomputer. BASIC language is used throughout to give the designer rapid interaction and control. Both designs integrate compact first stage coils with concentric tubular heaters. The hybrid heater design allows better thruster power matching with the spacecraft power bus. Projected specific impulse levels were 760 to 830 s for hydrogen and 380 to 410 s for ammonia

A design study of hydrazine and biowaste resistojets

A generalized modeling program was adapted in BASIC on a personal computer to compare the performance of four types of biowaste resistojets and two types of hydrazine augmenters. Analyzed biowaste design types were: (1) an electrically conductive ceramic heater-exchanger of zirconia; (2) a truss heater of platinum in cross flow; (3) an immersed bicoiled tubular heater-exchanger; and (4) a nonexposed, refractory metal, radiant heater in a central cavity within a heat exchanger case. Concepts 2 and 3 are designed to have an efficient, stainless steel outer pressure case. The hydrazine design types are: (5) an immersed bicoil heater exchanger and (6) a nonexposed radiant heater now with a refractory metal case. The ceramic biowaste resistojet has the highest specific impulse growth potential at 2000 K of 192.5 (CO2) and 269 s (H2O). The bicoil produces the highest augmenter temperature of 1994 K for a 2073 K heater giving 317 s at .73 overall efficiency. Detailed temperature profiles of each of the designs are shown. The scaled layout drawings of each are presented with recommended materials and fabrication methods

Goal framing of health related behaviors: What factors contribute to the persuasiveness of a message?

There is evidence that the manner in which relevant information is framed can influence decisions that are based on that information. That is, information may be presented in a positive frame (i.e., describing benefits gained from engaging in behaviors) or in a negative frame (i.e., describing losses from not engaging in behaviors). The effect of information frame on older adults\u27 decision to comply or not comply with health behavior recommendations is unclear due to a paucity of research. In an attempt to understand factors that influence older adult healthy behavior decision making, the current study examined variables that might predict whether positively or negatively framed information elicits greater compliance with health recommendations. Positively and negatively framed messages promoting skin cancer prevention and detection were distributed to older and younger adults. Participants rated their intentions to engage in prevention and detection behaviors. Intentions to engage in prevention behaviors was related to lower numeracy ability. Additionally, intentions to engage in prevention behaviors were stronger among older adults than younger adults. No significant difference was found across numeracy ability or age groups in intentions to engage in detection behaviors. Additionally, there were not significant differences in intentions to engage in prevention or detection behaviors when the efficacy level of these behaviors varied. History of engaging in prevention behaviors was related to intentions to engage in future prevention behaviors in the positive frame condition and in the negative frame condition. In conclusion, older adults reacted similarly to younger adults following exposure to framed messages, and endorsed stronger intentions than the younger adults to engage in prevention behaviors regardless of message frame. Additionally, positively-framed prevention messages were more persuasive than negatively-framed messages among people with a history of engaging in prevention behaviors. Recommendations for future research include examining variables associated with increased compliance among individuals with a weaker history of engaging in the recommended behaviors should be explored in future studies

The effects of framing on decision making: Collaborative versus individual decision making among older adults

The framing effect in medical decision making was examined using individual and collaborative older adult decision makers. One hundred eight adults over the age of 60 participated. A lung cancer scenario was presented to each participant, with the option of choosing surgery or radiation for treatment. Participants viewed the options in either a positive (survival) or negative (mortality) frame. A mixed design was used, with frame (positive or negative) and condition (individual or collaborative) as the between subject factors, and data format (cumulative probability, interval probability, and life expectancy) as the within subject factor. Individuals demonstrated the framing effect in one data format, life expectancy, by choosing surgery in the positive frame and radiation in the negative frame more often than expected by chance. Collaborative decision makers demonstrated the framing effect in two data formats, cumulative and interval probability. Collaborators indicated higher confidence ratings in the data format where the framing effect was not exhibited as compared to the data formats where the framing effect was exhibited. There were no other differences in confidence and use of information ratings across data formats or between decision makers who demonstrated the framing effect and decision makers who did not demonstrate the framing effect

Intravenous versus subcutaneous drug administration. Which do patients prefer? A systematic review

BACKGROUND: Intravenous (IV) drug delivery is commonly used for its rapid administration and immediate drug effect. Most studies compare IV to subcutaneous (SC) delivery in terms of safety and efficacy, but little is known about what patients prefer. METHODS: A systematic review was conducted by searching seven electronic databases for articles published up to February 2014. Included studies were randomized controlled trials (RCTs) and/or crossover designs investigating patient preference for SC versus IV administration. The risk of bias in the RCTs was determined using the Cochrane Collaboration tool. Reviewers independently extracted data and assessed the risk of bias. Any discrepancies were resolved by consensus. RESULTS: The search identified 115 publications, but few (6/115) met the inclusion criteria. Patient populations and drugs investigated were diverse. Four of six studies demonstrated a clear patient preference for SC administration. Main factors associated with SC preference were time saving and the ability to have treatment at home. Only three studies used study-specific instruments to measure preference. CONCLUSIONS: Results suggest that patients prefer SC over IV delivery. Patient preference has clearly been neglected in clinical research, but it is important in medical decision making when choosing treatment methods as it has implications for adherence and quality of life. If the safety and efficacy of both administration routes are equivalent, then the most important factor should be patient preference as this will ensure optimal treatment adherence and ultimately improve patient experience or satisfaction. Future drug efficacy and safety studies should include contemporaneous, actual patient preference where possible, utilizing appropriate measures

Group B streptococcal infection and activation of human astrocytes.

BACKGROUND:Streptococcus agalactiae (Group B Streptococcus, GBS) is the leading cause of life-threatening meningitis in human newborns in industrialized countries. Meningitis results from neonatal infection that occurs when GBS leaves the bloodstream (bacteremia), crosses the blood-brain barrier (BBB), and enters the central nervous system (CNS), where the bacteria contact the meninges. Although GBS is known to invade the BBB, subsequent interaction with astrocytes that physically associate with brain endothelium has not been well studied. METHODOLOGY/PRINCIPAL FINDINGS:We hypothesize that human astrocytes play a unique role in GBS infection and contribute to the development of meningitis. To address this, we used a well- characterized human fetal astrocyte cell line, SVG-A, and examined GBS infection in vitro. We observed that all GBS strains of representative clinically dominant serotypes (Ia, Ib, III, and V) were able to adhere to and invade astrocytes. Cellular invasion was dependent on host actin cytoskeleton rearrangements, and was specific to GBS as Streptococcus gordonii failed to enter astrocytes. Analysis of isogenic mutant GBS strains deficient in various cell surface organelles showed that anchored LTA, serine-rich repeat protein (Srr1) and fibronectin binding (SfbA) proteins all contribute to host cell internalization. Wild-type GBS also displayed an ability to persist and survive within an intracellular compartment for at least 12 h following invasion. Moreover, GBS infection resulted in increased astrocyte transcription of interleukin (IL)-1β, IL-6 and VEGF. CONCLUSIONS/SIGNIFICANCE:This study has further characterized the interaction of GBS with human astrocytes, and has identified the importance of specific virulence factors in these interactions. Understanding the role of astrocytes during GBS infection will provide important information regarding BBB disruption and the development of neonatal meningitis