Negative Differential Conductance & Hot-Carrier Avalanching in Monolayer WS2 FETs

The high field phenomena of inter-valley transfer and avalanching breakdown have long been exploited in devices based on conventional semiconductors. In this Article, we demonstrate the manifestation of these effects in atomically-thin WS2 field-effect transistors. The negative differential conductance exhibits all of the features familiar from discussions of this phenomenon in bulk semiconductors, including hysteresis in the transistor characteristics and increased noise that is indicative of travelling high-field domains. It is also found to be sensitive to thermal annealing, a result that we attribute to the influence of strain on the energy separation of the different valleys involved in hot-electron transfer. This idea is supported by the results of ensemble Monte Carlo simulations, which highlight the sensitivity of the negative differential conductance to the equilibrium populations of the different valleys. At high drain currents (>10 μA/μm) avalanching breakdown is also observed, and is attributed to trap-assisted inverse Auger scattering. This mechanism is not normally relevant in conventional semiconductors, but is possible in WS2 due to the narrow width of its energy bands. The various results presented here suggest that WS2 exhibits strong potential for use in hot-electron devices, including compact high-frequency sources and photonic detectors.

Aromatase expression in atypical ductal hyperplasia in women

PURPOSE

To determine the levels of aromatase in atypical ductal hyperplasia (ADH) lesions, tissue surrounding the ADH, and in dense and non-dense normal breast tissue. We postulated that excess aromatase in breast tissue might, through production of increased estrogen, drive the carcinogenic process. Estrogens and their metabolites are thought to contribute to the development of breast cancer through estrogen receptor-mediated mechanisms and genotoxic effects of estrogen metabolites. ADH is a benign lesion of the breast which is associated with substantially increased risk for subsequent development of breast cancer. After 25 years, approximately 30% of women with ADH develop breast cancer. In women with three or more separate ADH lesions at the same time, 47% will develop breast cancer over that time period. Another important risk factor for breast cancer is the presence of mammographically dense breast tissue.

METHODS

We utilized quantitative immunochemical analysis of aromatase in biopsy tissue to test this possibility. Previously published results comparing dense with non-dense breast tissue in normal women (Vachon et al. Breast Cancer Res Treat 125:243-252, 2011) were used for comparisons with ADH. A well-characterized histochemical H-score was employed for quantitative assessment of aromatase in the various tissue studied.

RESULTS

The H-score of aromatase staining was statistically significantly higher (p = 0.003) in the ADH epithelium than surrounding epithelial tissue. In order of H-score from highest to lowest were ADH, issue surrounding ADH, dense normal and non-dense normal breast tissues. The levels of aromatase in a subset of women with ADH who went on to develop breast cancer were not higher than in women who did not.

CONCLUSIONS

We suggest from these studies that overexpression of aromatase in breast tissue and its resultant increase in estradiol levels may contribute to the later development of breast cancer in women with ADH.

Abstract P1-02-08: Provista-002: A prospective, multi-center study to determine the effectiveness of a biomarker assay to distinguish benign from invasive breast cancer in women with BI-RADS 3, 4 and 5 imaging reports

This abstract was not presented at the symposium.

Abstract P4-17-02: Design, implementation and evaluation of a smoking cessation intervention for patients undergoing breast cancer surgery

Introduction:

Smoking is a risk factor for poor outcomes following breast reconstructive surgery, including wound dehiscence and infection. Women who would choose to have reconstructive surgery after mastectomy for breast cancer are unable to do so if they have not quit smoking. The specific aims of this project are to 1) design and implement an intervention to assist these patients in quitting and 2) evaluate its efficacy.

Methods:

Baseline data regarding current practices was collected via a chart review of 75 smoking breast cancer surgery patients from 1/1/2012-12/31/13. Charts were analyzed for documentation of smoking status, quit advice, resources provided and used, and smoking status at follow-up. Formative research informed the design of an Ask-Advise-Refer intervention for all new breast cancer patients seen at Mayo Clinic.

Intervention Design:

Smoking patients were identified prior to their initial Breast Cancer evaluation at Mayo Clinic, Rochester, during a standard intake call. Smoking status was documented by the rooming assistant to alert the physicians of smoking status, and physicians asked these patients about their smoking behavior, discussed the risks of smoking both for surgical procedures and breast cancer, and offered a Nicotine Dependence Consultation with a tobacco treatment specialist in an “opt-out” strategy that emphasized the importance of smoking cessation as part of the breast cancer treatment process. The advice and referral was documented in the medical record. Evaluation of the intervention was performed via a chart review of patients seen after one year of implementation.

Intervention Evaluation Results:

Breast clinic physicians documented smoking status in all patients seen after implementation. Referral to the Nicotine Dependence Center for cessation counseling increased from 29% (22/75) to 74% (20/27). Among those referred, attendance at the consultation increased from 41% (9/22) to 75% (15/20), suggesting stronger provider encouragement of cessation services. 30-day abstinence rates for those who attended a consult prior to 5/1/16 were 46% (6/13), which is consistent with baseline data.

Conclusions:

An Ask-Advise-Refer intervention for new breast cancer patients seen at Mayo Clinic, Rochester, who report current smoking, has been associated with higher rates of provider counseling on tobacco dependence, referral to available services, and patient attendance at referrals. Attending a referral greatly increases a patient's chances of quitting smoking for at least 30 days compared to average spontaneous quit rates in this population. This model is low-cost, time-efficient for providers, and applicable to most practice settings. Finding ways to make this intervention self-sustaining and applicable to multiple other practices could greatly improve our patient's health outcomes.

Citation Format: Nolan M, Ghosh K, Warner DO. Design, implementation and evaluation of a smoking cessation intervention for patients undergoing breast cancer surgery [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 P4-17-02.

Role of MMP-7 in the pathogenesis of systemic lupus erythematosus (SLE)

Systemic lupus erythematosus (SLE) is a clinically heterogeneous chronic, inflammatory autoimmune disorder. The association of MMP-7 and disease severity is still unclear. A total of 150 SLE patients and matched healthy controls were recruited for this study. Disease activity was scored according to SLEDAI (98 active and 52 inactive disease). Mean serum MMP-7 levels were significantly higher in SLE patients than controls ( p < 0.001). Patients with active disease showed higher levels (16.24 ± 6.2 ng/ml) as against inactive disease (10.50 ± 3.97 ng/ml) ( p ≤ 0.0001). Mean MMP-7 mRNA expression was significantly higher in patients (RQ = 3.16 ± 0.93) as compared to controls (RQ = 2.21 ± 0.89, p = 0.006). A positive correlation between MMP-7 levels, mRNA expression and SLEDAI score was observed ( r = 0.563, r = 0.427). The MMP-7 -181 G allele was found to be significantly higher among SLE patients ( p < 0.0001). A significant association was noted between MMP-7 -181 A/G +G/G genotypes with renal ( p = 0.0027) and CNS ( p = 0.0031) manifestations and anti-dsDNA autoantibodies ( p = 0.0312). Serum MMP-7 levels and mRNA expression were elevated in advanced stages of SLE, indicating that MMP-7 is associated with disease activity in SLE.

Individualization of antiretroviral therapy--pharmacogenomic aspect

Combination therapy with three drug regimens for human immunodeficiency virus (HIV) infection significantly suppresses the viral replication. However, this therapeutic impact is restricted by adverse drug events and response in terms of short and long term efficacy. There are multiple factors involved in different responses to antiretrovirals (ARVs) such as age, body weight, disease status, diet and heredity. Pharmacogenomics deals with individual genetic make-up and its role in drug efficacy and toxicity. In depth genetic research has provided evidence to predict the risk of developing certain toxicities for which personalized screening and surveillance protocols may be developed to prevent side effects. Here we describe the use of pharmacogenomics for optimal use of HAART (highly active antiretroviral therapy).

Amnion Epithelial Cells of Buffalo (Bubalus Bubalis) Term Placenta Expressed Embryonic Stem Cells Markers and Differentiated into Cells of Neurogenic Lineage In Vitro

Aim of the present study was the isolation, culture, and characterization of amniotic membrane-derived epithelial cells (AE) from term placenta collected postpartum in buffalo. We found that cultured cells were of polygonal in shape, resistance to trypsin digestion and expressed cytokeratin-18 indicating that they were of epithelial origin. These cells have negative expression of mesenchymal stem cell markers (CD29, CD44, and CD105) and positive for pluripotency marker (OCT4) genes indicated that cultured cells were not contaminated with mesenchymal stem cells. Immunofluorescence staining with pluripotent stem cell surface markers, SSEA-1, SSEA-4, TRA-1-60, and TRA-1-81 indicated that these cells may retain pluripotent stem cell characteristics even after long period of differentiation. Differentiation potential of these cells was determined by their potential to differentiate into cells of neurogenic lineages using retinoic acid. In conclusion, we demonstrate that AE cells expressed pluripotent stem cell markers and have propensity to differentiate into cells of neurogenic lineage upon directed differentiation in vitro.

Annexin A5 levels or circulating microparticles: what we see depends mainly on what we look for

Click here to view the article Letter to the Editor by C. Reutelingsperger et al.