Atom-by-atom chemical identification from scanning transmission electron microscopy images in presence of noise and residual aberrations.

The simple dependence of the intensity in annular dark field scanning transmission electron microscopy images on the atomic number provides (to some extent) chemical information about the sample, and even allows an elemental identification in the case of light-element single-layer samples. However, the intensity of individual atoms and atomic columns is affected by residual aberrations and the confidence of an identification is limited by the available signal to noise. Here, we show that matching a simulation to an experimental image by iterative optimization provides a reliable analysis of atomic intensities even in presence of residual non-round aberrations. We compare our new method with other established approaches demonstrating its high reliability for images recorded at limited dose and with different aberrations. This is of particular relevance for analyzing moderately beam-sensitive materials, such as most 2D materials, where the limited sample stability often makes it difficult to obtain spectroscopic information at atomic resolution.

A Review of Developing Communication Skills for Students with Intellectual and Developmental Disabilities on College Campuses.

In the current investigation, we reviewed the literature on communication interventions for individuals with intellectual and developmental disabilities (IDD) on college campuses. Eight studies met our inclusion criteria. Data were extracted related to participant demographics (e.g., disability, response form, type of postsecondary program) and study variables (e.g., design, settings, intervention). We evaluated the methodological quality of each study using the National Technical Assistance Center on Transition's Quality Indicator Checklist for single-case design studies. Results indicated a dearth of literature in this critical area and that extant literature reflected a primary research emphasis on the use of multi-component packages to teach communication skills to students with mild or no intellectual disability. Limitations and implications for research and practice for transition professionals and university campus providers are discussed.

Small-Group Technology-Assisted Instruction: Virtual Teacher and Robot Peer for Individuals with Autism Spectrum Disorder.

The authors combined virtual reality technology and social robotics to develop a tutoring system that resembled a small-group arrangement. This tutoring system featured a virtual teacher instructing sight words, and included a humanoid robot emulating a peer. The authors used a multiple-probe design across word sets to evaluate the effects of the instructional package on the explicit acquisition and vicarious learning of sight words instructed to three children with autism spectrum disorder (ASD) and the robot peer. Results indicated that participants acquired, maintained, and generalized 100% of the words explicitly instructed to them, made fewer errors while learning the words common between them and the robot peer, and vicariously learned 94% of the words solely instructed to the robot.

Brief Report: An Evaluation of an Instructional Package for Teaching Sentence Construction to Students with ASD.

In the current study, we investigated the effects of an instructional package on the construction of sentences writing by four children ages 6-9, with autism spectrum disorder (ASD). We employed a multiple probe across behaviors design to evaluate the efficacy of the intervention package and also conducted probes to assess generalization and increases in the use of spoken sentences. Data indicated that the package was effective and produced variable levels of maintenance and generalized responding across three of the participants. Further, changes in vocal responding were observed in one of the participants.

Frequency of Mand Instruction Reported in Behavioral, Special Education, and Speech Journals.

The authors reviewed 10 years of research literature on teaching mands to individuals with developmental disabilities. Articles were selected from journals associated with three professional organizations (e.g., Association for Behavior Analysis, Council for Exceptional Children, and American Speech and Hearing Association). Findings were reported as frequencies of publication across journals and sets of journal. Furthermore, we reported on the several contextual variables reported within each study (i.e., age of participants, setting, change agent, response topography, generalization). Implications for practitioners are discussed.

Inversion of Dynamical Scattering from Large-Angle Rocking-Beam Electron Diffraction Patterns.

A method for ab initio structure factor retrieval from large-angle rocking-beam electron diffraction data of thin crystals is described and tested with experimental and simulated data. No additional information, such as atomicity or information about chemical composition, has been made use of. Our numerical experiments show that the inversion of dynamical scattering works best, if the beam tilt range is large and the specimen not too thick, because for moderate multiple scattering, the large tilt amplitude effectively removes local minima in this global optimization problem.

Surface effects on mean inner potentials studied using density functional theory.

Quantitative materials characterization using electron holography frequently requires knowledge of the mean inner potential, but reported experimental mean inner potential measurements can vary widely. Using density functional theory, we have simulated the mean inner potential for materials with a range of different surface conditions and geometries. We use both "thin-film" and "nanowire" specimen geometries. We consider clean bulk-terminated surfaces with different facets and surface reconstructions using atom positions from both structural optimization and experimental data and we also consider surfaces both with and without adsorbates. We find that the mean inner potential is surface-dependent, with the strongest dependency on surface adsorbates. We discuss the outlook and perspective for future mean inner potential measurements.

A three-dimensional polarization domain retrieval method from electron diffraction data.

We present an algorithm for retrieving three-dimensional domains of picometer-scale shifts in atomic positions from electron diffraction data, and apply it to simulations of ferroelectric polarization in BaTiO3. Our algorithm successfully and correctly retrieves polarization domains in which the Ti atom positions differ by less than 3 pm (0.4% of the unit cell diagonal distance) with 5 and 10nm depth resolution along the beam direction, and we also retrieve unit cell strain, corresponding to tetragonal-to-cubic unit cell distortions, for 10nm domains. Experimental applicability is also discussed.

Retrieving depth-direction information from TEM diffraction data under reciprocal-space sampling variation.

For full three-dimensional information retrieval from transmission electron microscope data, retrieving the third-dimension (beam-direction) information is an important challenge. Recently, we have developed an artificial-neural-network-based retrieval algorithm suitable for retrieving three-dimensional nanoscale crystal parameters like strain, including with noisy data (R.S. Pennington, W. Van den Broek, C.T. Koch, Phys. Rev. B 89 (20) (2014) 205409 [12]). In this work, we examine how reciprocal-space sampling conditions influence the retrieved crystal parameters, using crystal tilt as an example parameter, and demonstrate retrieval for 2.5 nm depth resolution. For noise-free data, we find that the total reciprocal-space area is the key parameter; however, when the data are noisy, the number of reciprocal-space points and the amount of noise are also influential. We also apply our algorithm to a simulated bent specimen, and recover the bending as expected. Guidelines for experimental applications are also discussed.

Stacked-Bloch-wave electron diffraction simulations using GPU acceleration.

In this paper, we discuss the advantages for Bloch-wave simulations performed using graphics processing units (GPUs), based on approximating the matrix exponential directly instead of performing a matrix diagonalization. Our direct matrix-exponential algorithm yields a functionally identical electron scattering matrix to that generated with matrix diagonalization. Using the matrix-exponential scaling-and-squaring method with a Padé approximation, direct GPU-based matrix-exponential double-precision calculations are up to 20× faster than CPU-based calculations and up to approximately 70× faster than matrix diagonalization. We compare precision and runtime of scaling and squaring methods with either the Padé approximation or a Taylor expansion. We also discuss the stacked-Bloch-wave method, and show that our stacked-Bloch-wave implementation yields the same electron scattering matrix as traditional Bloch-wave matrix diagonalization.

Improving cover-letter writing skills of individuals with intellectual disabilities.

We evaluated a multicomponent intervention for improving the cover-letter writing skills of individuals with intellectual disabilities. An intervention that included modeling, self-monitoring, prompting, and feedback increased correct performance for all participants. In addition, the skill was demonstrated across audiences.

Geometric reconstruction methods for electron tomography.

Electron tomography is becoming an increasingly important tool in materials science for studying the three-dimensional morphologies and chemical compositions of nanostructures. The image quality obtained by many current algorithms is seriously affected by the problems of missing wedge artefacts and non-linear projection intensities due to diffraction effects. The former refers to the fact that data cannot be acquired over the full 180° tilt range; the latter implies that for some orientations, crystalline structures can show strong contrast changes. To overcome these problems we introduce and discuss several algorithms from the mathematical fields of geometric and discrete tomography. The algorithms incorporate geometric prior knowledge (mainly convexity and homogeneity), which also in principle considerably reduces the number of tilt angles required. Results are discussed for the reconstruction of an InAs nanowire.

An alternative technique for immediate breast reconstruction.

Immediate reconstruction has demonstrated superior cosmesis compared with delayed reconstruction, however, unexpected final pathology may necessitate post mastectomy radiation. We describe an alternative technique for immediate breast reconstruction. Twelve patients underwent 14 skin-sparing mastectomies from July 2006 to December 2009. The skin-sparing mastectomies and sentinel node biopsies were performed through a periareolar incision. At the completion of the operation the incision was closed in a transverse fashion. No simultaneous reconstruction was performed. No drains were placed. After 3 days seroma developed, which maintained the integrity of the skin envelope and appearance of a breast. Nine patients (75%) had a contraindication to breast conservation. All patients were clinically node negative and 67 per cent were clinical stage 0. The majority (75%) experienced an adverse change from clinical stage to final pathologic stage. Four patients (33%) required postmastectomy radiation. The mean time from oncologic procedure to initial reconstruction procedure was 14 days. Two patients (17%) developed postoperative infections. This technique allows immediate reconstruction and avoids the fear of adverse final pathology indicating radiation to the reconstructed breast. In addition, it provides flexibility in scheduling for the surgeons and allows the patient to maintain the appearance of the breast.

Compliance differences between patients with breast cancer in university and county hospitals.

PURPOSE: Compliance with recommended breast cancer treatments outside the context of a clinical trial differs from that in study populations. The purpose of this study was to examine differences in compliance of breast cancer treatments. PATIENTS AND METHODS: We conducted a retrospective review of 529 patients treated at 2 teaching hospitals in the same city from 2003 to 2006. Compliance with adjuvant therapy recommendations and choice of breast-conserving operations were compared between a university hospital (UH) and a county hospital (CH). RESULTS: The 2 populations demonstrated similar rates of breast conservation (72% vs. 69%). Although use of radiation therapy at the CH was acceptable (82%), patients at the UH were more likely to undergo radiation therapy (95%). The use of hormone therapy was similar at the UH and the CH (> 93%). Patients were more likely to follow physician recommendations for adjuvant chemotherapy at the UH (89%) compared with the CH (70%; P = .0005). Univariate analysis revealed that patient age, tumor size, stage, grade, and estrogen receptor status were all significant predictors of patient compliance with chemotherapy. Preoperative chemotherapy was a strong predictor of patient compliance with chemotherapy (P < .0001). In multivariate analysis, all of the factors predictive of patient compliance in univariate analysis remained significant except tumor grade. CONCLUSION: Preoperative chemotherapy appeared to increase compliance compared with adjuvant chemotherapy in the CH population. Compared with national standards, breast-conserving operations and radiation therapy compliance can be accomplished in an acceptable percentage of underinsured patients.

Race and ethnicity and breast cancer outcomes in an underinsured population.

BACKGROUND: The disparity in breast cancer mortality between African American women and non-Hispanic white women has been the subject of increased scrutiny. Few studies have addressed these differences in the setting of equal access to health care. We compared the breast cancer outcomes of underinsured African American and non-Hispanic white patients who were treated at a single institution. METHODS: We conducted a retrospective review of medical records for breast cancer patients who were treated at Wishard Memorial Hospital from January 1, 1997, to February 28, 2006. A total of 574 patients (259 non-Hispanic whites and 315 African Americans) were evaluated. A Cox proportional hazards regression analysis for competing risks was performed. All statistical tests were two-sided. RESULTS: Sociodemographic characteristics were similar in the two groups, and both racial groups were equally unlikely to have undergone screening mammography during the 2 years before diagnosis. Most (84%) of the patients were underinsured. The median time from diagnosis to operation, receipt of adequate surgery, and use of all types of adjuvant therapy were similar in the two groups. Median follow-up was 80.3 months for non-Hispanic whites and 77.9 months for African Americans. After accounting for the effect of comorbidities, African American race was statistically significantly associated with breast cancer-specific mortality (African Americans vs non-Hispanic whites: 26.0% vs 17.5%, P = .028; hazard ratio [HR] of death = 1.64, 95% confidence interval [CI] = 1.06 to 2.55). Adjustment for age at diagnosis, clinical stage, and hormone receptor status attenuated the effect, and the effect of race on breast cancer-specific survival was no longer statistically significant (HR of death from breast cancer = 1.43, 95% CI = 0.89 to 2.30). After adjustment for sociodemographic factors, the hazard ratio for race was further attenuated (HR = 1.26; 95% CI = 0.79 to 2.00). CONCLUSIONS: In this underinsured population, African American patients had poorer breast cancer-specific survival than non-Hispanic white patients. After adjustment for clinical and sociodemographic factors, the effect of race on survival was no longer statistically significant.

A molecular signature of normal breast epithelial and stromal cells from Li-Fraumeni syndrome mutation carriers.

Specific changes in gene expression during cancer initiation should enable discovery of biomarkers for risk assessment, early detection and targets for chemoprevention. It has been previously demonstrated that altered mRNA and proteome signatures of morphologically normal cells bearing a single inherited "hit" in a tumor suppressor gene parallel many changes observed in the corresponding sporadic cancer. Here, we report on the global gene expression profile of morphologically normal, cultured primary breast epithelial and stromal cells from Li-Fraumeni syndrome (LFS) TP53 mutation carriers. Our analyses identified multiple changes in gene expression in both morphologically normal breast epithelial and stromal cells associated with TP53 haploinsufficiency, as well as interlocking pathways. Notably, a dysregulated p53 signaling pathway was readily detectable. Pharmacological intervention with the p53 rescue compounds CP-31398 and PRIMA-1 provided further evidence in support of the central role of p53 in affecting these changes in LFS cells and treatment for this cancer. Because loss of signaling mediated by TP53 is associated with the development and survival of many human tumors, identification of gene expression profiles in morphologically normal cells that carry "one-hit" p53 mutations may reveal novel biomarkers, enabling the discovery of potential targets for chemoprevention of sporadic tumors as well.

Junctions in axial III-V heterostructure nanowires obtained via an interchange of group III elements.

We present an investigation of the morphology and composition of novel types of axial nanowire heterostructures where Ga(x)In(1-x)As is used as barrier material in InAs nanowires. Using aberration-corrected scanning transmission electron microscopy and energy dispersive X-ray analysis we demonstrate that it is possible to grow junctions by changing the group III elements, and we find that a substantial fraction of Ga can be incorporated in axial InAs/Ga(x)In(1-x)As/InAs, retaining straight nanowire configurations. We explain how the adatoms are transferred to the incorporation site at the growth interface via two different routes, (1) interface diffusion and (2) volume diffusion through the catalyst particle.

The effect of dedicated breast surgeons on the short-term outcomes in breast cancer.

OBJECTIVE: The impact of breast surgeons on short-term outcomes in breast cancer care was compared at a single institution. SUMMARY BACKGROUND DATA: Many studies have demonstrated a correlation between high procedural volume and lower mortality in technically challenging procedures. Breast cancer treatment has significant impact on patient behavior, psychology, and appearance. Therefore, evaluation of outcomes cannot be limited to only operative mortality and morbidity. We sought to determine the effect of dedicated breast cancer surgeons on short-term outcomes at a single institution. METHODS: Wishard Memorial Hospital is the county hospital affiliated with the Indiana University School of Medicine. A retrospective review was performed of all patients from January 1, 1997, to February 28, 2006. On July 1, 2003, coverage for the Breast Clinic was changed from general surgeons (G) to breast surgeons (B). There were 596 patients included in the study period. RESULTS: There were no significant differences in patient demographics or disease characteristics between the 2 time periods. For early stage (stage I and II) breast cancer, a higher percentage of patients underwent breast conservation in the breast surgeon period than in the general surgeon period (P = 0.04). Lumpectomy margins in breast conserving operations during the G period were more often positive (P = 0.025) or close (<1 mm) (P = 0.01). Similarly, the rates of re-excision lumpectomy were also significantly lower during the B period (21% vs. 39%, respectively, P = 0.01). Breast surgeons were more likely to perform the sentinel node procedure (P = 0.001). There were no differences in the use of adjuvant chemotherapy and radiation therapy. The use of hormonal manipulation, however, was significantly higher in the B group than in the G group (P < 0.0002). CONCLUSIONS: Surgeons specialized in diseases of the breast demonstrate significant improvement in short-term outcomes associated with breast cancer treatment at a single institution. The differences identified cannot be attributed to differences in institutional function, patient population, surgeon case volume, or on the influence of nonsurgeon physicians.

Frequency of sentinel lymph node metastases in patients with favorable breast cancer histologic subtypes.

BACKGROUND: The need for axillary nodal staging in favorable histologic subtypes of breast cancer is controversial. METHODS: Patients with clinical stage T1-2, N0 breast cancer were enrolled in a prospective, multi-institutional study. All patients underwent sentinel lymph node (SLN) biopsy followed by completion level I/II axillary dissection. RESULTS: SLN were identified in 3,106 of 3,324 patients (93%). Axillary metastases were found in 35% and 40% of patients with infiltrating ductal carcinoma and infiltrating lobular carcinoma, respectively. Among tumor subtypes, positive nodes were found in 17% of patients with pure tubular carcinoma, 7% of patients with papillary cancer, 6% of patients with colloid (mucinous) carcinoma, 21% of patients with medullary carcinoma, and 8% of patients with DCIS with microinvasion. CONCLUSIONS: Patients with favorable breast cancer subtypes have a significant rate of axillary nodal metastasis. Axillary nodal staging remains important in such patients; SLN biopsy is an ideal method to obtain this staging information.