Quasi-Van der Waals Epitaxial Growth of γ'-GaSe Nanometer-Thick Films on GaAs(111)B Substrates.

GaSe is an important member of the post-transition-metal chalcogenide family and is an emerging two-dimensional (2D) semiconductor material. Because it is a van der Waals material, it can be fabricated into atomic-scale ultrathin films, making it suitable for the preparation of compact, heterostructure devices. In addition, GaSe possesses unusual optical and electronic properties, such as a shift from an indirect-bandgap single-layer film to a direct-bandgap bulk material, rare intrinsic p-type conduction, and nonlinear optical behaviors. These properties make GaSe an appealing candidate for the fabrication of field-effect transistors, photodetectors, and photovoltaics. However, the wafer-scale production of pure GaSe single-crystal thin films remains challenging. This study develops an approach for the direct growth of nanometer-thick GaSe films on GaAs substrates by using molecular beam epitaxy. It yields smooth thin GaSe films with a rare γ'-polymorph. We analyze the formation mechanism of γ'-GaSe using density-functional theory and speculate that it is stabilized by Ga vacancies since the formation enthalpy of γ'-GaSe tends to become lower than that of other polymorphs when the Ga vacancy concentration increases. Finally, we investigate the growth conditions of GaSe, providing valuable insights for exploring 2D/three-dimensional (3D) quasi-van der Waals epitaxial growth.

Pilot testing a patient decision aid as a strategy to reduce overtreatment for older women with early-stage breast cancer.

BACKGROUND: Despite national guidelines recommending omission of sentinel lymph node biopsy (SLNB) and post-lumpectomy radiotherapy (RT) in older women with early-stage, hormone receptor-positive (HR+) breast cancer, these practices persist. This pilot study assesses whether a decision aid can target patient-level determinants of low-value treatments. METHODS: We adapted and pilot-tested a decision aid in women ≥70 years old with early-stage HR â€‹+ â€‹breast cancer. Primary outcomes included acceptability and appropriateness of the decision aid. Secondary outcomes included treatment choice and satisfaction with decision. RESULTS: Twenty-three patients enrolled in the trial. 19 completed survey one; 16 completed survey two. Primary outcomes demonstrated that 84% of patients agreed or strongly agreed the aid was acceptable and appropriate. Secondary outcomes demonstrated that 19% of patients underwent SLNB (below pre-intervention baseline), and 85% received adjuvant RT (change not statistically significant). CONCLUSIONS: We demonstrate that a decision aid may effectively target patient-level factors contributing to overuse of low-value therapies.

Timing of mastectomy and the effect on the likelihood of outpatient surgery and cost savings in breast cancer patients.

BACKGROUND: Same-day discharge after mastectomy has potential patient- and hospital-level benefits; however, few data are available regarding factors affecting the likelihood of same-day discharge in order to address barriers. We sought to evaluate factors contributing to same-day discharge, focusing on the timing of mastectomy during the operative day. METHODS: We conducted a single-institution retrospective review of patients who underwent mastectomies for malignancy over a 3-y time frame. Clinicopathologic variables were collected along with a binary variable for mastectomy start time (morning versus afternoon). Our primary endpoint was rate of same-day discharge. A multivariable logistic regression model was constructed from significant univariate variables to determine independent predictors of same-day discharge. A secondary endpoint was a cost-utility analysis for morning versus afternoon start time, using hospital cost data. RESULTS: There were 451 patients included in the analysis. Factors associated with same-day discharge rate included the American Society of Anesthesiologists score, use of a preoperative regional anesthesia block, type of mastectomy performed, individual surgeon variation, and a morning start for the mastectomy. On multivariable analysis, morning start was a strong independent predictor of same-day discharge (odd ratio = 2.83; 95% CI, 1.75-4.60). The cost-utility analysis favored a morning start, with average cost savings of $550 per patient. CONCLUSION: Despite patient- and surgeon-specific variations, simple scheduling policies can improve same-day discharge rates after mastectomy, leading to improved hospital bed use and cost reduction.

Proximity-induced superconductivity in epitaxial topological insulator/graphene/gallium heterostructures.

The introduction of superconductivity to the Dirac surface states of a topological insulator leads to a topological superconductor, which may support topological quantum computing through Majorana zero modes1,2. The development of a scalable material platform is key to the realization of topological quantum computing3,4. Here we report on the growth and properties of high-quality (Bi,Sb)2Te3/graphene/gallium heterostructures. Our synthetic approach enables atomically sharp layers at both hetero-interfaces, which in turn promotes proximity-induced superconductivity that originates in the gallium film. A lithography-free, van der Waals tunnel junction is developed to perform transport tunnelling spectroscopy. We find a robust, proximity-induced superconducting gap formed in the Dirac surface states in 5-10 quintuple-layer (Bi,Sb)2Te3/graphene/gallium heterostructures. The presence of a single Abrikosov vortex, where the Majorana zero modes are expected to reside, manifests in discrete conductance changes. The present material platform opens up opportunities for understanding and harnessing the application potential of topological superconductivity.

Contemporary approaches to the axilla in breast cancer.

Over the past decade, axillary management in breast cancer has fundamentally shifted. The former notion that any degree of axillary nodal involvement warrants axillary lymph node dissection (ALND) has been challenged. Following publication of the ACOSOG Z0011 trial, national trends demonstrated significant reductions in ALND performance. Axillary radiotherapy in lieu of ALND is a consideration for select patients with a positive sentinel lymph node, while ongoing studies are investigating the role of adjuvant regional radiotherapy in women with positive nodes prior to neoadjuvant chemotherapy. Efforts toward de-escalation of axillary surgery continue to evolve, as do the indications for sentinel node biopsy omission in select subsets of patients. This review highlights the recent advances and neoteric approaches to local therapy of the axilla in breast cancer.

Prophylactic mastectomy and occult malignancy: Surgical and imaging considerations.

BACKGROUND: Sentinel node biopsy (SLNB) is not routinely recommended for patients undergoing prophylactic mastectomy (PM), yet omission remains a subject of debate among surgeons. A modern patient cohort was examined to determine occult malignancy (OM) incidence within PM specimens to reinforce current recommendations. METHODS: All PM performed over a 5-year period were retrospectively identified, including women with unilateral breast cancer who underwent synchronous or delayed contralateral PM or women with elevated cancer risk who underwent bilateral PM. RESULTS: The study population included 772 patients (598 CPM, 174 BPM) with a total of 39 OM identified: 17 invasive cancers (14 CPM, 3 BPM) and 22 DCIS (19 CPM, 3 BPM). Of the 86 patients for whom SLNB was selectively performed, 1 micrometastasis was identified. In the CPM cohort, risk of OM increased with age, presence of LCIS of either breast, or presence of a non-BRCA high-penetrance gene mutation, while preoperative magnetic resonance imaging was associated with lower likelihood of OM. CONCLUSIONS: Given the low incidence of invasive OM in this updated series, routine SLNB is of low value for patients undergoing PM. For patients with indeterminate radiographic findings, discordant preoperative biopsies, LCIS, or non-BRCA high-penetrance gene mutations, selective SLNB implementation could be considered.

Management of early stage HER2 positive breast cancer and increased implementation of axillary imaging to improve identification of nodal metastasis.

BACKGROUND AND OBJECTIVES: Given the significant benefit of targeted therapies for HER2+ breast cancer patients in both the neoadjuvant and adjuvant settings, it is critical to identify all eligible patients for these treatments. We sought to investigate cT1cN0 HER2+ patients to determine the rate of postsurgical nodal positivity, and to identify presurgical factors associated with nodal positivity. We hypothesize there is a subset of underdiagnosed HER2+ patients who would benefit from preoperative axillary imaging and inclusion in neoadjuvant chemotherapy regimens. METHODS: We performed a 10-year retrospective analysis of T1 HER2+ breast cancer patients. Clinicopathologic characteristics were evaluated based on surgical nodal data. RESULTS: We identified 38 patients with cT1cN0 HER2+ cancer. Of this cohort, 24% had positive lymph nodes on final pathology. High tumor grade (p = 0.035) on core needle biopsy and the presence of lymphovascular invasion (p = 0.0036) were associated with an increased likelihood of lymph node positivity. The majority (66%) of lymph node positive patients were clinically T1c. CONCLUSIONS: We identified a 24% nodal positivity rate in clinically node negative T1 HER2+ breast cancer patients. In particular, HER2+ patients with high-grade T1c cancers should undergo preoperative diagnostic axillary imaging to expand potential benefit from targeted therapies.

The role of breast MRI in newly diagnosed breast cancer: An evidence-based review.

The utility of pre-operative MRI in patients with newly diagnosed invasive breast cancer remains a topic of debate. Those who advocate for pre-treatment imaging contend that MRI may detect additional disease not otherwise appreciated on conventional imaging and may provide more accurate staging information to guide treatment. Additionally, it has been proposed that MRI can be utilized to assess extent of residual disease in patients undergoing neoadjuvant chemotherapy. Conversely, those in opposition maintain that routine pre-operative MRI subjects patients to unnecessary ipsilateral mastectomies and prophylactic contralateral mastectomies with no difference in oncologic outcome. When stratified based on tumor biology and patient characteristics, the data suggests that pre-treatment MRI may be advantageous in certain subsets when compared to the general cohort of breast cancer patients. This review recapitulates the current literature on the impact of breast MRI on the surgical management and outcomes of newly diagnosed breast cancer.

Impact of Neoadjuvant Versus Adjuvant Chemotherapy on the Extent of Axillary Surgery for Clinically Node-Negative Breast Cancers of Triple-Negative and HER2-Overexpressing Phenotypes.

BACKGROUND: Breast cancer patients with triple-negative or human epidermal growth factor receptor 2 (HER2)-overexpressing phenotypes are recommended to receive chemotherapy for primary tumors greater than 1 cm regardless of nodal status. Neoadjuvant chemotherapy may eradicate subclinical nodal metastases and reduce the extent of axillary surgery performed. PATIENTS AND METHODS: A query of the National Cancer Database Participant User File was performed for new cases of female breast cancer from 2012 to 2015. Inclusion criteria were clinical N0 status, receipt of chemotherapy, and receipt of axillary surgery. Exclusions included hormone-positive/HER2-negative tumors and/or distant metastatic disease. Subjects were divided into groups by receipt of neoadjuvant or adjuvant chemotherapy. The primary end point was the extent of axillary surgery, defined as sentinel lymph node biopsy alone or axillary lymph node dissection (ALND). Subgroup analyses were performed on the basis of tumor phenotype and surgery of the primary site. RESULTS: A total of 66,771 female patients were included, 15,967 of whom underwent neoadjuvant chemotherapy. ALND rates were higher in patients who received adjuvant chemotherapy (30.6% vs. 28.8%, P < .001). Among tumor phenotypes, the extent of axillary surgery was reduced most significantly for hormone-negative, HER2-positive disease (30.0% vs. 25.8%, P < .001). ALND rates were more substantially reduced for patients who underwent mastectomy (41.3% vs. 36.1%, P < .001) compared to partial mastectomy (21.8% vs. 20.1%, P = .002). Adjuvant chemotherapy was an independent predictor of ALND (odds ratio, 1.26; 95% confidence interval, 1.19-1.33). CONCLUSION: Neoadjuvant chemotherapy reduces the extent of axillary surgery in clinically node-negative, nonluminal breast cancers.

Climate change images produce an attentional bias associated with pro-environmental disposition.

Humans have developed mechanisms to prioritize certain sensory input(s). Emotionally salient stimuli automatically capture observers' attention at the cost of less salient information. This prioritized processing is called attentional bias. Images of climate change have been found to elicit emotional responses. Yet, to date, there is no research assessing the extent to which climate change-relevant images produce an attentional bias. In a sample of college students (N = 39), we found that (1) climate change-related images capture attention and that (2) this attentional bias is related to individual differences in environmental disposition. Thus, images of climate change are salient-attention grabbing-signals related to pro-environmental orientation.

Zebrafish as a model for Vibrio parahaemolyticus virulence.

Vibrio parahaemolyticus is a Gram-negative, naturally occurring marine bacterium. Subpopulations of strains belonging to this species cause an acute self-limiting gastroenteritis in humans and, less commonly, wound infections. In vivo models to differentiate avirulent and virulent strains and evaluate the pathogenic potential of strains of this species have been largely focused on the presence of known virulence factors such as the thermostable direct haemolysin (TDH), the TDH-related haemolysin (TRH) or the contributions of the type 3 secretion systems. However, virulence is likely to be multifactorial, and additional, yet to be identified factors probably contribute to virulence in this bacterium. In this study, we investigated an adult zebrafish model to assess the overall virulence of V. parahaemolyticus strains. The model could detect differences in the virulence potential of strains when animals were challenged intraperitoneally, based on survival time. Differences in survival were noted irrespective of the source of isolation of the strain (environmental or clinical) and regardless of the presence or absence of the known virulence factors TDH and TRH, suggesting the influence of additional virulence factors. The model was also effective in comparing differences in virulence between the wild-type V. parahaemolyticus strain RIMD2210633 and isogenic pilin mutants ΔpilA and ΔmshA, a double mutant ΔpilA : ΔmshA, as well as a putative chitin-binding protein mutant, ΔgbpA.

Natural resource manager perceptions of agency performance on climate change.

An important precursor to the adoption of climate change adaptation strategies is to understand the perceived capacity to implement and operationalize such strategies. Utilizing an importance-performance analysis (IPA) evaluation framework, this article presents a comparative case study of federal and state land and natural resource manager perceptions of agency performance on factors influencing adaptive capacity in two U.S. regions (northern Colorado and southwestern South Dakota). Results revealed several important findings with substantial management implications. First, none of the managers ranked the adaptive capacity factors as a low priority. Second, managers held the perception that their agencies were performing either neutrally or poorly on most factors influencing adaptive capacity. Third, gap analysis revealed that significant improvements are required to facilitate optimal agency functioning when dealing with climate change-related management issues. Overall, results suggest that a host of institutional and policy-oriented (e.g., lack of clear mandate to adapt to climate change), financial and human resource (e.g., inadequate staff and financial resources), informational (e.g., inadequate research and monitoring programs) and contextual barriers (e.g., sufficient regional networks to mitigate potential transboundary impacts) currently challenge the efficient and effective integration of climate change into decision-making and management within agencies working in these regions. The IPA framework proved to be an effective tool to help managers identify and understand agency strengths, areas of concern, redundancies, and areas that warrant the use of limited funds and/or resource re-allocation in order to enhance adaptive capacity and maximize management effectiveness with respect to climate change.