Thermally stable Peltier controlled vacuum chamber for electrical transport measurements

The design, manufacture, and characterization of an inexpensive, temperature-controlled vacuum chamber with millikelvin stability for electrical transport measurements at and near room temperature is reported. A commercially available Peltier device and a high-precision temperature controller are used to actively heat and cool the sample space. The system was designed to minimize thermal fluctuations in spintronic and semiconductor transport measurements, but the general principle is relevant to a wide range of electrical measurement applications. The main issues overcome are the mounting of a sample with a path of high thermal conductivity through to the Peltier device and the heat sinking of the said Peltier device inside a vacuum. A copper slug is used as the mount for a sample, and a large copper block is used as a thermal feedthrough before a passive heat sink is used to cool this block. The Peltier device provides 20 W of heating and cooling power, achieving a maximum range of 30 K below and 40 K above the ambient temperature. The temperature stability is within 5 mK at all set points with an even better performance above the ambient temperature. A vacuum pressure of 10-8 hPa is achievable. As a demonstration, we present experimental results from current-induced electrical switching of a CuMnAs thin film. Transport measurements with and without the Peltier control emphasize the importance of a constant temperature in these applications. The thermal lag between the sample space measurement and the sample itself is observed through magnetoresistance values measured during a temperature sweep.

Antiferromagnetic half-skyrmions electrically generated and controlled at room temperature

Topologically protected magnetic textures are promising candidates for information carriers in future memory devices, as they can be efficiently propelled at very high velocities using current-induced spin torques. These textures-nanoscale whirls in the magnetic order-include skyrmions, half-skyrmions (merons) and their antiparticles. Antiferromagnets have been shown to host versions of these textures that have high potential for terahertz dynamics, deflection-free motion and improved size scaling due to the absence of stray field. Here we show that topological spin textures, merons and antimerons, can be generated at room temperature and reversibly moved using electrical pulses in thin-film CuMnAs, a semimetallic antiferromagnet that is a testbed system for spintronic applications. The merons and antimerons are localized on 180° domain walls, and move in the direction of the current pulses. The electrical generation and manipulation of antiferromagnetic merons is a crucial step towards realizing the full potential of antiferromagnetic thin films as active components in high-density, high-speed magnetic memory devices.

Place Is Power: Investing in Communities as a Systemic Leverage Point to Reduce Breast Cancer Disparities by Race

Racial disparities in breast cancer present a vexing and complex challenge for public health. A diverse array of factors contributes to disparities in breast cancer incidence and outcomes, and, thus far, efforts to improve racial equity have yielded mixed results. Systems theory offers a model that is well-suited to addressing complex issues. In particular, the concept of a systemic leverage point offers a clue that may assist researchers, policymakers, and interventionists in formulating innovative and comprehensive approaches to eliminating racial disparities in breast cancer. Naming systemic racism as a fundamental cause of disparities, we use systems theory to identify residential segregation as a key leverage point and a driver of racial inequities across the social, economic, and environmental determinants of health. We call on researchers, policymakers, and interventionists to use a systems-informed, community-based participatory approach, aimed at harnessing the power of place, to engage directly with community stakeholders in coordinating efforts to prevent breast cancer, and work toward eliminating disparities in communities of color.

The Role of Stress in Breast Cancer Incidence: Risk Factors, Interventions, and Directions for the Future

Stress is a common belief among breast cancer patients and the public to explain variation in breast cancer incidence. Epidemiological studies interrogating the relationship between stress and cancer have reported mixed results. The impact of the topic and the lack of consensus has sparked this review of the literature to investigate gaps in knowledge and identify areas of research. We first present a brief summary of the biopsychosocial model generally used to conduct research on stress. We then divide the overview of the literature into areas of research focus. These include the role of distressing life events in breast cancer incidence, the role of adverse childhood events in later breast cancer incidence, the importance of race and socioeconomic status (SES) as social determinants of breast cancer incidence, and the specific role of chronic stress in relation to breast cancer. For each topic, we discuss the potential of stress as a risk factor and possible intervention strategies that could reduce the effects of stress. We then identify further research questions to be probed to fill the gaps in knowledge. We conclude with a discussion of future research directions for stress research as it relates to breast cancer incidence.

Searching beyond the Lamppost to Reduce Breast Cancer Disparities

Racial and ethnic differences in breast cancer occur by race/ethnicity in both incidence and mortality rates. Women of lower socioeconomic status likewise have poorer outcomes. When race alone is considered, incidence rates in the United States are highest among White women (130.8 per 100,000), with Black women close behind (126.7 per 100,000). Incidence is lowest among Asian/Pacific Islander women, at 93.2 per 100,000. Mortality differences are more pronounced, with Black women 40% more likely to die from breast cancer than White women (28.4 per 100,000 and 20.3 per 100,000, respectively). Mortality rates for Asian/Pacific Islander women (11.5 per 100,000) are far lower than for Black and White women. When age is considered, additional differences between Black and White women appear, in part accounted for by types of breast cancer experienced. Women of other racial/ethnic groups and socioeconomic status have received less scientific attention. In this article, we provide a brief overview of the evidence for social determinants of breast cancer and argue that the current reliance on race over racism and ethnicity contributes to our inability to eliminate breast cancer disparities in the United States and elsewhere in the world. We suggest alternatives to the current approach to research in breast cancer disparities.

Development and Evaluation of a Training Program for Community-Based Participatory Research in Breast Cancer

This paper describes the development and feasibility of the Community Based Research Infrastructure to Better Science (CRIBS) training. The goal of this training program was to help new or existing community-academic teams to build strong partnerships and successfully develop together fundable research projects focused on breast cancer environmental causes and disparities. A comprehensive mixed-methods participatory approach was utilized to assess the training. Twenty-two community-academic teams applied for the training program; twelve teams were enrolled. All teams completed the training and subsequently submitted research applications for funding. All components of the training received high ratings and positive qualitative comments. Self-rated competency in all of the learning domains increased during the training. Four (33%) of teams were successful in their first attempt to garner research funding, and six (50%) were eventually successful. The evaluation of CRIBS found it to have successfully achieved all four goals of the training: (1) Twelve new CBPR (community-based participatory research) teams, (2) improved knowledge about CBPR and science, (3) twelve submitted grant proposals in the first year, and (4) six (50%) successfully funded research projects.