Wet Etching and Surface Analysis of Chemically Treated InGaN Films

This paper discusses the performance of different wet chemical etchants on InGaN. It is shown that certain etchants can be used to chemically etch and remove appreciable amounts of InGaN even though the etch rate is not as high as observed for other III-V materials. The performance of etchants studied here were (i) two different ratios of HF, HNO3, (ii) cyclic usage of NH4OH followed by HCl, (iii) hot H2SO4 and H3PO4 mixture, and (iv) conc. NH4OH. The etched surfaces have then been analyzed by x-ray photoelectron spectroscopy (XPS). Different etch residues were observed on the top surface. These results suggest an alternative to reactive plasma etching or photo-enhanced electrochemical etching of InGaN type materials. Based on the observed performance of the etchants studied, it was also possible to segregate the surface cleaning protocols and etchants

Critical Issues: Defining and Debunking Misconceptions in Health, Education, Criminal Justice, and Social Work/Social Services

The University of Houston Downtown Committee for the Journal of Family Strengths introduces Volume 18, Issue 1: Critical Issues: Defining and Debunking Misconceptions in Health, Education, Criminal Justice, and Social Work/Social Services

Measuring Accuracy of Automated Parsing and Categorization Tools and Processes in Digital Investigations

This work presents a method for the measurement of the accuracy of evidential artifact extraction and categorization tasks in digital forensic investigations. Instead of focusing on the measurement of accuracy and errors in the functions of digital forensic tools, this work proposes the application of information retrieval measurement techniques that allow the incorporation of errors introduced by tools and analysis processes. This method uses a `gold standard' that is the collection of evidential objects determined by a digital investigator from suspect data with an unknown ground truth. This work proposes that the accuracy of tools and investigation processes can be evaluated compared to the derived gold standard using common precision and recall values. Two example case studies are presented showing the measurement of the accuracy of automated analysis tools as compared to an in-depth analysis by an expert. It is shown that such measurement can allow investigators to determine changes in accuracy of their processes over time, and determine if such a change is caused by their tools or knowledge.Comment: 17 pages, 2 appendices, 1 figure, 5th International Conference on Digital Forensics and Cyber Crime; Digital Forensics and Cyber Crime, pp. 147-169, 201

Comparative Network Analysis of Preterm vs. Full-Term Infant-Mother Interactions

Several studies have reported that interactions of mothers with preterm infants show differential characteristics compared to that of mothers with full-term infants. Interaction of preterm dyads is often reported as less harmonious. However, observations and explanations concerning the underlying mechanisms are inconsistent. In this work 30 preterm and 42 full-term mother-infant dyads were observed at one year of age. Free play interactions were videotaped and coded using a micro-analytic coding system. The video records were coded at one second resolution and studied by a novel approach using network analysis tools. The advantage of our approach is that it reveals the patterns of behavioral transitions in the interactions. We found that the most frequent behavioral transitions are the same in the two groups. However, we have identified several high and lower frequency transitions which occur significantly more often in the preterm or full-term group. Our analysis also suggests that the variability of behavioral transitions is significantly higher in the preterm group. This higher variability is mostly resulted from the diversity of transitions involving non-harmonious behaviors. We have identified a maladaptive pattern in the maternal behavior in the preterm group, involving intrusiveness and disengagement. Application of the approach reported in this paper to longitudinal data could elucidate whether these maladaptive maternal behavioral changes place the infant at risk for later emotional, cognitive and behavioral disturbance

A Review of Graphite and Gold Surface Studies for Use as Substrates in Biological Scanning Tunneling Microscopy Studies

The current status of biological Scanning Tunneling Microscopy (STM) investigations and the importance of using a well-characterized substrate are discussed. The findings of over two years of experiments and over 1,000 images obtained on gold substrates prepared by a variety of different methods are statistically summarized and compared to a very flat reference substrate, highly oriented pyrolytic graphite (HOPG). In an effort to begin to corroborate STM results with those obtained from other more established techniques, the results of Auger Electron Spectroscopy (AES) and Electron Spectroscopy for Chemical Analysis (ESCA) of biomolecular STM samples are presented

Electron Spectroscopy and Atomic Force Microscopy Studies of DNA Adsorption on Mica

Various methods for the deposition of deoxyribonucleic acid (DNA) molecules on mica are investigated to determine their reproducibility, and to quantify their ability to bind DNA. The use of these deposition methods for sample preparation for biological scanning tunneling microscopy (STM) and atomic force microscopy (AFM) studies is discussed. Auger electron spectroscopy (AES) and electron spectroscopy for chemical analysis (ESCA) were used to investigate the quantity of DNA adsorbed. AFM images of DNA deposited using the methods investigated are presented. The combination of AFM results with AES and ESCA results provides a basic understanding of the deposition techniques studied and illustrates that electron spectroscopy can be a useful addition to studies of this nature

Soft Ion Sputtering of PAni Studied by XPS, AFM, TOF-SIMS, and STS

Herein is a study of the soft sputtering method, gas cluster ion sputtering (GCIS), and its effects on the atomic, morphologic, and band structure properties of polyaniline (PAni) as studied with X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry, atomic force microscopy, and scanning tunneling spectroscopy (STS). The GCIS source used was a 1000 argon atom cluster with 4 keV energy, which resulted in a sputter yield of 3.4 ± 0.2 × 10−3 nm3 per argon atom. Soft ion sputtering reduced the sample by explicitly removing the oxidized contaminants as determined by surface sensitive techniques: XPS and Time-of-flight secondary ion mass spectrometry (TOF-SIMS). By the use of STS we found that by removing the oxidized components, an overall shift of electronic states occurred, transitioning the states closer to the Fermi edge by 0.3 V

Developmental perspectives on interpersonal affective touch

In the last decade, philosophy, neuroscience and psychology alike have paid increasing attention to the study of interpersonal affective touch, which refers to the emotional and motivational facets of tactile sensation. Some aspects of affective touch have been linked to a neurophysiologically specialised system, namely the C tactile (CT) system. While the role of this sys-tem for affiliation, social bonding and communication of emotions have been widely investigated, only recently researchers have started to focus on the potential role of interpersonal affective touch in acquiring awareness of the body as our own, i.e. as belonging to our psychological ‘self’. We review and discuss recent developmental and adult findings, pointing to the central role of interpersonal affective touch in body awareness and social cognition in health and disorders. We propose that interpersonal affective touch, as an interoceptive modality invested of a social nature, can uniquely contribute to the ongoing debate in philosophy about the primacy of the relational nature of the minimal self

3,4-Methylenedioxymethamphetamine Activates Nuclear Factor- κB, Increases Intracellular Calcium, and Modulates Gene Transcription in Rat Heart Cells

3,4-Methylenedioxymethamphetamine (MDMA) is an illicit psychoactive drug that has gained immense popularity among teenagers and young adults. The cardiovascular toxicological consequences of abusing this compound have not been fully characterized. The present study utilized a transient transfection/dual luciferase genetic reporter assay, fluorescence confocal microscopy, and gene expression macroarray technology to determine nuclear factor-κB (NF-κB) activity, intracellular calcium balance, mitochondrial depolarization, and gene transcription profiles, respectively, in cultured rat striated cardiac myocytes (H9c2) exposed to MDMA. At concentrations of 1×10−3 M and 1×10−2 M, MDMA significantly enhanced NF-κB reporter activity compared with 0 M (medium only) control. This response was mitigated by cotransfection with IκB for 1×10−3 M but not 1×10−2 M MDMA. MDMA significantly increased intracellular calcium at concentrations of 1×10−3 M and 1×10−2 M and caused mitochondrial depolarization at 1×10−2 M. MDMA increased the transcription of genes that are considered to be biomarkers in cardiovascular disease and genes that respond to toxic indults. Selected gene activation was verified via temperature-gradient RT-PCR conducted with annealing temperatures ranging from 50°C to 65°C. Collectively, these results suggest that MDMA may be toxic to the heart through its ability to activate the myocardial NF-κB response, disrupt cytosolic calcium and mitochondrial homeostasis, and alter gene transcription