cssi/SciSciGPT-SciSciNet huggingface dataset:
Reduced ballistic limit velocity of graphene membranes due to cone wave reflection

Abstract Recent microscale ballistic experiments have revealed that multilayer graphene membranes exhibit exceptionally high ballistic limit velocity and specific penetration energy. A key feature contributing to the exceptional performance of these systems is the cone wave that develops at impact, which propagates radially at a very high speed for ultra-light and stiff graphene membranes, distributing the kinetic energy of the projectile away from the impact zone. Current theories on ballistic impact consider infinitely wide membranes, and atomistic simulations involve very small projectiles and specimen dimensions, and thus cannot ascertain whether microscale ballistics observations are scalable and size-independent. Here, we discover a particular size effect due to the reflection of cone wave that has not been previously observed or considered. We present molecular dynamics simulations showing that there exists a critical membrane size below which the cone wave reflections from the boundaries induce perforation; a phenomenon that is particularly relevant for microballistic testing of graphene membranes. We present an analytical relationship, verified by simulation data, which predicts the critical membrane size simply as a function of the projectile size, membrane thickness and the ratio of the projectile and membrane densities. Our findings provide timely guidance for future microscale experiments and atomistic simulations for accurate characterization of the impact performance of 2D nanomaterials.
Post Traumatic Stress Disorder in Children and Adolescents: Conceptualization and Treatment

Publisher Summary This chapter explains the post traumatic stress disorder (PTSD) in children and adolescents. The diagnostic classification of PTSD emerged from the post-war era. In recent years, PTSD symptomatology has been noted in adults exposed to extreme stressors other than war, such as rape, natural disasters, terrorism, and automobile accidents. This chapter presents two different theoretical models, family systems therapy (FST) and cognitive behavioral therapy (CBT), for the conceptualization and treatment of post traumatic stress disorder in children and adolescents. It is important for the clinicians to understand the behavior and diagnostic entity based in a theoretical framework. FST focuses on a family systems approach in the treatment of PTSD. FST therapists attempt to alter the family system in various ways to achieve the ultimate goal of symptom reduction. Two types of FST include structural family therapy and strategic family therapy. Structural family therapists suggest that the family is a system that functions in specific social contexts. In addition, strategic family therapists hail from a family systems perspective and hence also believe that problems do not evolve in a linear manner but rather are circular in development. An alternative conceptualization for PTSD acquisition and treatment includes a CBT model. This theory offers explanation for children exhibiting a more adverse PTSD response to intrafamilial abuse than extrafamilial abuse. Finally, in order to meet diagnostic criteria for PTSD, symptoms must be evident for more than one month and must cause significant distress or disruption in social, occupational and academic, and other functioning.
Moving from STEM to STEAM: The effects of informal STEM learning on students' creativity and problem solving skills with 3D printing

Modeling with 3D computer-aided design (CAD) software to design and print 3D products can improve students' spatial visualization skills, creativity, and problem solving skills. 3D CAD software has been used as a teaching tool in secondary school classrooms since the early 2000s, but it becoming more ubiquitous due to increased affordability of an innovative concept: 3D printing. Yet research about the effect of 3D design and printing on students' academic achievement, problem solving skills, and creativity has been limited. For the present study, the effects of applying 3D CAD software and 3D printing were observed on students' perceptions of their need for creativity when solving problems that could be encountered across STEM careers. Participants (N = 95) were high school students who attended a two-week long STEM summer camp at a university located in central Texas in 2016. Results indicated that the students who participated in the 3D CAD and printing improved their perceptions about creativity and problem solving skills required for STEM disciplines (p < .01). The effect for the study was impressive with Cohen's d effect sizes for students' perceptions about creativity and problem solving skills in STEM disciplines at d = 0.61 and d = 0.66, respectively. Students who participated in the informal STEM learning and engaged with 3D project-based learning indicated that creativity was important for STEM fields and for engineering in particular. They also indicated that problem solving skills were essential for being successful in a STEM career. Teachers who desire to increase their students' creativity along with their STEM competencies should integrate classroom activities that promote creativity and problem solving while being actively engaged in the activity.
Primary malignant perivascular epithelioid cell neoplasm (PEComa) of the bone mimicking granular cell tumor in core biopsy: A case report and literature review

The present study investigated the case of a 46-year-old female with primary malignant perivascular epithelioid cell neoplasm (PEComa) of the femur. The patient presented with a 5-month history of right distal thigh pain following trauma. Radiographs of the right distal femur revealed a mixed lytic and sclerotic lesion with subtle areas of cortical destruction and soft tissue extension, consistent with an aggressive tumor. A core biopsy revealed an epithelioid tumor with granular cell features, but a definitive diagnosis could not be made. Due to the aggressive features on radiologic evaluation, the patient underwent a resection of the distal femur and reconstruction with a distal femoral megaprosthesis and hinged knee replacement. The post-resection pathology led to a final diagnosis of primary bone PEComa, with histologic features including epithelioid, granular cell and spindled cell morphologies and biphasic immunoreactivity for melanocytic and smooth muscle markers. The large tumor size (>5 cm), rapid mitotic rate, infiltrative growth pattern, high nuclear grade and cellularity, and the presence of necrosis rendered this a malignant PEComa. The present study discussed the case, including radiographic (radiographs, magnetic resonance imaging and positron emission tomography scans) and histologic appearance and a literature review.
Sirolimus enhances remission induction in patients with high risk acute myeloid leukemia and mTORC1 target inhibition

Background Mammalian Target of Rapamycin Complex 1 (mTORC1) inhibitors enhance chemotherapy response in acute myelogenous leukemia (AML) cells in vitro. However whether inhibiting mTORC1 enhances clinical response to AML chemotherapy remains controversial. We previously optimized measurement of mTORC1’s kinase activity in AML blasts during clinical trials using serial phospho-specific flow cytometry of formaldehyde-fixed whole blood or marrow specimens. To validate mTORC1 as a therapeutic target in AML, we performed two clinical trials combining an mTORC1 inhibitor (sirolimus) and MEC (mitoxantrone, etoposide, cytarabine) in patients with relapsed, refractory, or untreated high-risk AML. Methods Flow cytometric measurements of ribosomal protein S6 phosphorylation (pS6) were performed before and during sirolimus treatment to determine whether mTORC1 inhibition enriched for chemotherapy response. Results In 51 evaluable subjects, the overall response rate (ORR) to the combination regimen was 47% (95% confidence interval 33–61%, 33% CR, 2% CRi, 12% PR) and similar toxicity to historic experience with MEC alone. 37 subjects had baseline pS6 measured pre-sirolimus, of whom 27 (73%) exhibited mTORC1 activity. ORR was not significantly different between subjects with and without baseline mTORC1 activity (52% vs 40%, respectively, p = 0.20). The ORR among subjects with baseline target activation and mTORC1 inhibition during therapy was 71% (12/17) compared to 20% (2/10) in subjects without target inhibition. Conclusions Fixed, whole blood pS6 by flow cytometry may be a predictive biomarker for clinical response to mTORC1 inhibitor-based regimens. These data provide clinical confirmation that mTORC1 activation mediates chemotherapy resistance in patients with AML.
Predictive Linguistic Markers of Suicidality in Poets

Suicidal rates have been increasing since 2000 according the latest report of Centers for disease control and prevention. Today internet opens a channel where people can communicate and information remains registered, making acoustic, semantic and syntactic analyses especially appealing to find hidden cues that can be used to detect signs of different mental conditions. Here we analyze poems from poets who committed suicide to develop a method to detect suicidal signs. We use bipartite graph matching algorithms after data retrieval to assure our results are not susceptible to bias created by variation in poem sample size among poets, and focus on linguistic content (e.g. similarity to specific concepts) and structure (e.g. density of ideas). Our results using different classifiers yield accuracy rates of up to 86% to discriminate suicidal from non-suicidal poets.
Computer-Aided Diagnosis of Digital Mammography and Ultrasound Images of Breast Mass Lesions

Although general rules for the differentiation between benign and malignant mammographically-identified breast lesions exist, considerable misclassification of lesions occurs with current imaging and interpretation methods [1]–[6]. The purpose of our study is to develop computerized methods for the analysis of mass lesions on digitized mammograms and on ultrasound images for aiding in the task of distinguishing between malignant and benign lesions. This should lead to (1) an improvement in the classification sensitivity for malignant lesions and (2) an increase in the classification specificity and thus, a reduction in the number of unnecessary biopsies. Higher performance is expected when a combination of features from mammographie and ultrasound images is used as an aid to radiologists in the task of distinguishing between malignant and benign lesions.
Super Resolution with Meta-Lenses

In the previous two chapters, we described many intriguing properties in negative index materials (NIMs). One of the most striking predictions regarding NIMs as well as an exciting potential application is the “perfect lens.” Since light entering a NIM from free space will take a sharp turn at the interface, it is straightforward to see that a planar slab of NIM with sufficient thickness can act as a lens, sometimes dubbed as the Veselago lens. As depicted in Fig. 8.1c, diverging light rays from an object are negatively refracted at the first surface of the NIM slab, and the negative refraction of rays is repeated again at the second boundary. Consequently, the NIM slab creates an image within the slab and a second non-inverted image in the free space after the output interface. Compared to a conventional convex lens, the NIM lens looks quite exotic in that it does not have any axis or curvature, nor does it focus parallel rays or magnify small objects. All of these features were recognized in the seminal paper by Veselago [1]. The amazing properties of such a slab lens were first analyzed by J. B. Pendry, who pointed out that a slab with refractive index \(n = -1\) placed in vacuum allows the imaging of objects with sub-wavelength precision [2].
Current Developments in Anticoagulant and Antithrombotic Agents

Thrombosis is clearly the most common cause of death in the United States. About two million individuals die each year from an arterial or venous thrombosis or the consequences of these disorders. About 80% to 90% of all causes of thrombosis can now be defined with respect to cause. Of these, over 50% of all patients harbor a congenital or acquired blood coagulation protein or platelet defect which caused the thrombotic event. It is obviously of major importance to define those individuals harboring such a defect, as this allows (1) appropriate antithrombotic therapy to decrease risks of recurrence (2) determine length of time the patient must remain on therapy for secondary prevention and (3) allow for testing of family members in those harboring a blood coagulation protein or platelet defect which is hereditary (about 50% of all coagulation and platelet defects mentioned above). Aside from mortality, significant additional morbidity occurs from both arterial or venous thrombotic events, including, but not limited to paralysis (non-fetal thrombotic stroke), cardiac disability (repeated coronary events), loss of vision (retinal vascular thrombosis) and fetal waste syndrome (placental vascular thrombosis), stasis ulcers and other manifestations of post-phlebitic syndrome, etc.
Travels in North Africa: Orientalism or Frenchness?

Navarro-Ayala draws attention to Frenchmen who travel to North Africa in search of exotic ethnicized boys in homosexual adventures and bring with them a significant cultural cachet and strong socioeconomic power. Tales of the homosexual tourism industry indeed reveal an ongoing struggle to deal with the dyad of the privileged French tourist and marginal North African boys. Yet, Navarro-Ayala’s focus on the perspective of local teenagers makes it possible to trace their potential resistance to exploitation in such cross-cultural encounters. After a brief overview of sexual tourism in the French literary tradition, he therefore examines how Moroccan writers represent homosexual tourism in Morocco through the viewpoint of these young characters.
Mechanisms of CYP3A Induction During Pregnancy: Studies in HepaRG Cells

Activity of CYP3A, an enzyme responsible for metabolism of many marketed drugs, is induced by ~ 2-fold in pregnant women. Through studies in sandwich-cultured human hepatocytes (SCHH) and HepaRG cells, our laboratory has shown that this induction is likely mediated by the increase in cortisol plasma concentrations during pregnancy. Cortisol, at plasma concentrations observed during the third trimester (~ 800 nM), either alone or in combination with other pregnancy-related hormones, induces CYP3A activity in SCHH and HepaRG cells when cultured in dexamethasone-free media. To determine the mechanism(s) by which cortisol induces CYP3A activity, HepaRG cells were pre-incubated in dexamethasone-free medium and then incubated for 72 h with cortisol (798 nM). Glucocorticoid receptor (GR), pregnane X receptor (PXR), and CYP3A4 or CYP3A5 were knocked down using siRNA, and mRNA expression of these genes was measured. CYP3A4, and not CYP3A5, was found to be the dominant contributor to total CYP3A activity in control- and cortisol-treated HepaRG cells. Constitutive mRNA expression of CYP3A4 in HepaRG cells was regulated by both PXR and GR whereas constitutive expression of CYP3A5 in HepaRG cells was regulated by GR alone. Cortisol-mediated CYP3A4 induction in HepaRG cells was primarily mediated by GR-dependent PXR induction pathway and to a smaller extent via a PXR-independent pathway. Cortisol-mediated CYP3A5 induction was regulated by GR-dependent PXR-independent pathway. These data indicate that PXR plays a central role in cortisol-mediated induction of CYP3A activity during pregnancy and suggests that other enzymes and transporters, such as CYP2B6 and P-glycoprotein, may also be induced during pregnancy via the same mechanism(s).
Nusinersen for spinal muscular atrophy: Not just for babies?

Spinal muscular atrophy (SMA) is a monogenic anterior horn disease caused by mutations in the SMN1 gene leading to lack of SMN protein necessary for motor neuron functioning and survival. Phenotypic severity is modulated primarily by the amount of SMN protein produced by the paralogue SMN2 gene that differs from SMN1 by a critical single-nucleotide polymorphism in exon 7 (C to T) resulting in only 10%–15% of full-length functioning SMN protein. The phenotypes include subgroups with different age at onset, severity, and rate of progression: babies with type 1 SMA have onset of weakness before 6 months, are never able to sit, and have 8% survival at 20 months; babies with type 2 have symptoms onset after 6 months, they reach the ability to sit but never walk; children and teenagers with type 3 are able to walk, become progressively weaker, and eventually lose the ability to walk; the ultra-rare type 4 with adult onset has a very slow progression of lower extremity weakness. Nusinersen is an antisense oligonucleotide that corrects pre-mRNA splicing to promote inclusion of exon 7 in the SMN2 mRNA transcript, resulting in increased production of full-length functioning SMN protein.
Gene Expression and DNA Methylation Alterations During Non-alcoholic Steatohepatitis-Associated Liver Carcinogenesis

Hepatocellular carcinoma (HCC) is one of the most aggressive human cancers. HCC is characterized by an acquisition of multiple abnormal phenotypes driven by genetic and epigenetic alterations, especially abnormal DNA methylation. Most of the existing clinical and experimental reports provide only a snapshot of abnormal DNA methylation patterns in HCC rather than their dynamic changes. This makes it difficult to elucidate the significance of these changes in the development of HCC. In the present study, we investigated hepatic gene expression and gene-specific DNA methylation alterations in mice using the Stelic Animal Model (STAM) of non-alcoholic steatohepatitis (NASH)-derived liver carcinogenesis. Analysis of the DNA methylation status in aberrantly expressed epigenetically regulated genes showed the accumulation of DNA methylation abnormalities during the development of HCC, with the greatest number of aberrantly methylated genes being found in full-fledged HCC. Among these genes, only one gene, tubulin, beta 2B class IIB (Tubb2b), was increasingly hypomethylated and over-expressed during the progression of the carcinogenic process. Furthermore, the TUBB2B gene was also over-expressed and hypomethylated in poorly differentiated human HepG2 cells as compared to well-differentiated HepaRG cells. The results of this study indicate that unique gene-expression alterations mediated by aberrant DNA methylation of selective genes may contribute to the development of HCC and may have diagnostic value as the disease-specific indicator.
A Flow-Through Device for Simultaneous Dielectrophoretic Trapping and AC Electroporation

Cell isolation and selected transfection of those isolated cells is integral to single-cell analyses platforms. We present a scalable platform for simultaneous negative dielectrophoretic trapping and AC electroporation of cells and experimentally validate that cells can experience both phenomena simultaneously in a controlled manner. The geometry is scalable for single-cells. This has the potential to address two primary problems facing microscale electroporation: cell proximity to coplanar electrodes and material proximity to porated cells.
Changing suspended sediment in United States rivers and streams: linking sediment trends to changes in land use/cover, hydrology and climate

Abstract. Sediment is one of the leading pollutants in rivers and streams across the United States (US) and the world. Between 1992 and 2012, concentrations of annual mean suspended sediment decreased at over half of the 137 stream sites assessed across the contiguous US. Increases occurred at less than 25 % of the sites, and the direction of change was uncertain at the remaining 25 %. Sediment trends were characterized using the Weighted Regressions on Time, Discharge, and Season (WRTDS) model, and decreases in sediment ranged from −95 % to −8.5 % of the 1992 concentration. To explore potential drivers of these changes, the sediment trends were (1) parsed into two broad contributors of change, changes in land management versus changes in the streamflow regime, and (2) grouped by land use of the watershed and correlated to concurrent changes in land use or land cover (land use/cover), hydrology and climate variables and static/long-term watershed characteristics. At 83 % of the sites, changes in land management (captured by changes in the concentration–streamflow relationship over time; C–Q relationship) contributed more to the change in the sediment trend than changes in the streamflow regime alone (i.e., any systematic change in the magnitude, frequency or timing of flows). However, at >50 % of the sites, changes in the streamflow regime contributed at least a 5 % change in sediment, and at 11 sites changes in the streamflow regime contributed over half the change in sediment, indicating that at many sites changes in streamflow were not the main driver of changes in sediment but were often an important supporting factor. Correlations between sediment trends and concurrent changes in land use/cover, hydrology and climate were often stronger at sites draining watersheds with more homogenous, human-related land uses (i.e., agricultural and urban lands) compared to mixed-use or undeveloped lands. At many sites, decreases in sediment occurred despite small-to-moderate increases in the amount of urban or agricultural land in the watershed, suggesting conservation efforts and best-management practices (BMPs) used to reduce sediment runoff to streams may be successful, up to a point, as lands are converted to urban and agricultural uses.
International trade in commodities and labor: the case of the importation of Mexican agricultural labor and fresh market winter tomatoes into the US, 1964-1979

Currently, the United States is experiencing one of its most rapid periods of immigration in recent history, even though the Immigration Act of 1965 has established a quota of allowing approximately 120,000 legal Western hemisphere immigrants each year. The apparent paradox of rapid immigration in times of strict immigration legislation is due to the large numbers of Mexicans that are immigrating illegally to the United States and entering the labor force each year;The objectives of this study are: (1) To develop a 2-country, 1-commodity, 1-factor extended partial equilibrium trade model that will explain immigration and commodity and labor markets of the origin and destination countries. (2) To fit an empirical specification of this model to the U.S.-Mexican markets for traded winter tomatoes and for low-skilled farm labor during December-June for the period of 1964-1979. (3) To draw policy implications for illegal Mexican immigration into the United States;The situations of a large labor immigration from Mexico to the U.S. and the production of winter fresh tomatoes in Florida and Mexico have provided a unique setting for the adoption of a simple extended partial equilibrium trade model. A simple two-country, one-factor, and one-output extended partial equilibrium trade model has been developed to illustrate the interactions of the commodity and labor markets of Mexico and the U.S. and to provide for policy analysis in influencing the flow of illegal Mexican immigration. The results from the extended partial equilibrium trade model provide policy prescriptions that can be adopted by policy decision makers in the U.S. and Mexico in order to influence the flow of illegal Mexican immigration to the United States;The policy analysis suggests that Mexico and the U.S. should have cooperative domestic economic, trade and immigration policies in order to reduce the flow of illegal Mexican immigration. Mexico should encourage the further development of labor-intensive commodity production in order to absorb their excess supply of labor. The U.S. should coordinate trade policies that encourages the importation of labor-intensive commodities from Mexico rather than labor itself.
Surrogate indexes of insulin resistance and risk of metabolic syndrome in non-Hispanic White, non-Hispanic Black and Mexican American.

Abstract Aim To compare the strength of associations between surrogate indexes of insulin resistance (sIR) and risk of metabolic syndrome (MetS) in non-Hispanic White (NHW), non-Hispanic Black (NHB) and Mexican American (MA) adults. Methods The 2013–2016 US National Health and Nutrition Examination Survey data (n = 3435) were used for this study. The associations between sIR that includes Triglyceride/HDL cholesterol ratio (TG/HDL-C), triglyceride glucose (TG) index, visceral adiposity index (VAI), lipid accumulation product (LAP), TG-body mass index (TG-BMI), and TG-waist circumference (TG-WC) and risk for MetS were determined using the prevalence odds ratio (OR) from the logistic regression analyses. Pseudo-R-squared tests were used to estimate the proportion of variance in MetS accounted for by each sIR. Akaike Information Criterion and Bayesian Information Criterion from the multinomial logistic regression analysis were used to compare models that included each sIR and its components separately as predictors of MetS. Areas under curves (AUC) from the receiver-operating characteristic (ROC) were used to detect their diagnostic capabilities. Results Compared with other sIR, TG-WC (AUC = 0.899; 95% CI: 0.884–0.913 in NHW) and (AUC = 0.893; 95% CI:0.871–0.915 in NHB), and LAP (AUC = 877; 95% CI: 0.861–0.894 in MA) exhibited the highest diagnostic and predictive accuracy for MetS. Compared with other sIR, TG-WC (OR = 22.8; 95% CI:16.6–31.0 in NHW) and (OR = 22.7; 95% CI:13.1–39.3 in NHB), and LAP (OR = 10.6; 95%:6.6–17.0 in MA) were most significantly associated with increased odds of MetS, adjusting for eGFR, age, marital status, CHD, CHF, income, education, physical activity, alcohol use, smoking and use of cholesterol-lowering medication. Conclusions TG-WC in NHW and NHB, and LAP in MA are more powerful than other proxies of IR in predicting MetS. TG-WC and LAP can serve as adjunctive tools for screening for MetS in NHW, NHB, and MA.
Weak ferromagnetism in perovskite oxides

Weak ferromagnetism has been widely found in antiferromagnetic systems, including the technically important orthorhombic perovskites $R\mathrm{Fe}{\mathrm{O}}_{3}$ ($R=\mathrm{rare}\phantom{\rule{0.16em}{0ex}}\mathrm{earth}$) owing to spin canting associated with crystal symmetry. Antisymmetric exchange interaction (AEI) and single-ion anisotropy (SIA) are the essential mechanisms responsible for the development of noncollinear structures in antiferromagnetic systems. AEI and SIA share the same structural restriction to facilitate the spin canting. While both AEI and SIA originate from the spin-orbit coupling effect, they have sharply different dependences on the local structure. Consideration of the structural dependence of a canted spin motivates us to revisit the orthoferrite family. The spin canting along the $c$ axis measured on precisely oriented crystals increases monotonically from $\mathrm{La}\mathrm{Fe}{\mathrm{O}}_{3}$ to $\mathrm{Lu}\mathrm{Fe}{\mathrm{O}}_{3}$. Based on Moriya's model, AEI is sensitive to the octahedral-site distortion in the perovskite structure. However, the site distortion does not exhibit a monotonic change with the rare-earth substitution. Instead, a linear relationship has been found in both the octahedral rotation and the spin canting angle versus the rare-earth ionic radius, which indicates that SIA plays a significant role leading the spin canting in orthoferrites.
Examining the Effect of an Interdisciplinary Literacy Program on Student Learning

The literacy design collaborative (LDC) was created to support teachers in implementing college and career readiness standards. Teachers work collaboratively with coaches to further develop their expertise and design standards-driven, literacy-rich writing assignments within their existing curriculum across content areas. The current paper reports on early student academic outcome results from a multi-year mixed methods study of the implementation and effect of LDC using a quasi-experimental design, as implemented in one large urban school district. We found LDC had statistically significant effects on Cohort 2 middle school students’ English language arts (ELA) performance, an effect size of (d = 0.15) for students receiving LDC instruction in the three core content areas LDC focuses on: ELA, science, and social studies/history.
Tropical Data Science over the Space of Phylogenetic Trees

Phylogenomics is a new field which applies to tools in phylogenetics to genome data. Due to a new technology and increasing amount of data, we face new challenges to analyze them over a space of phylogenetic trees. Because a space of phylogenetic trees with a fixed set of labels on leaves is not Euclidean, we cannot simply apply tools in data science. In this paper we review first some new developments of machine learning models using tropical geometry to analyze a set of phylogenetic trees over a tree space. Then we define machine learning models using tropical geometry for phylogenomics. We end this article with open problems.
Oblique angle deposition of boron carbide films by magnetron sputtering

Many applications of boron carbide ( B4C) films entail deposition on non-planar substrates, necessitating a better understanding of oblique angle deposition phenomena. Here, we systematically study the effect of substrate tilt on properties of B4C films with thicknesses up to 10 μm deposited by direct current magnetron sputtering. Results show that all films are amorphous and columnar with an average column width of ∼100 nm, independent of substrate tilt. Column tilt angles are limited to ∼20° even for substrate tilt of 80°. Film density, residual stress, and the refractive index weakly (within ≲20%) depend on substrate tilt. Oxygen impurities bond preferentially with carbon atoms in inter-columnar regions. Substrate tilt has a major effect on mechanical properties that decrease by ∼50%, suggesting weak interconnection between nano-columns. Implications of these observations for the deposition onto non-planar substrates are discussed.
Moving the Bar on Computationally Sound Exclusive-Or

Soundness of symbolic security with respect to computational security was originally investigated from the point of cryptographic protocol design. However, there has been an emerging interest in applying it to the automatic generation and verification of cryptographic algorithms. This creates a challenge, since it requires reasoning about low-level primitives like exclusive-or whose actual behavior may be inconsistent with any possible symbolic behavior.
Constraints on the sulfur subduction cycle in Central America from sulfur isotope compositions of volcanic gases

Abstract The sulfur cycle at convergent margins remains poorly constrained yet is fundamentally important for understanding the redox state of Earth's reservoirs and the formation of ore deposits. In this study we investigate the sulfur isotope composition of high temperature volcanic gases emitted from the Nicaraguan (average of +4.8 ± 1.3‰) and Costa Rican (average of +2.3 ± 1.3‰) arc segments contributing to emissions from the Southern Central American Volcanic Arc (SCAVA; average of +3.8 ± 1.7‰). Along-arc variations in geochemical tracers at SCAVA are widely accepted to reflect variations in subduction parameters and deep fluid sources and correlations between these parameters and gas S isotope compositions are observed. These correlations suggest that gas emissions are sourced from a mixture of mantle S with δ34S ~ 0‰ and isotopically heavy slab-derived sulfur with δ34S ~ +8‰. We employ Monte Carlo mass balance modeling to constrain S inputs to the subduction zone and relative contributions from mantle and slab to arc gas emissions. The models indicate that bulk subduction input in Nicaragua has a S isotope composition of +1.4 ± 0.5‰ compared to −0.2 ± 0.4‰ in Costa Rica, requiring preferential release of isotopically heavy oxidized S from the slab to explain the relatively high δ34S observed in arc outputs. We show that the flux of S from the slab is sufficient to oxidize the entire mantle wedge within the lifetime of the arc, indicating that S is a primary oxidizing agent in subduction zones. Furthermore, the preferential removal of heavy S from the slab requires retention of isotopically light S in the residual slab. Subduction-scale fractionation of S isotopes is fundamentally important in explaining why Earth's bulk surface reservoirs are isotopically positive.
Optical Data Storage Using Phase Separation of Polymer-Liquid Crystal Mixtures

A polymer-liquid crystal mixture has been studied for possible reversible optical storage applications. At ambient temperature, this system exhibits a phase-separated morphology. It can be heated past its lower critical solution temperature, briefly forming a single phase. The laser-heated sample is then allowed to cool back into a two-phase state at various cooling rates. Through control of the heating pulse shape, the mixture and its substrate can be given varying temperature profiles at the completion of heating, thus influencing the subsequent cooling rate. Faster cooling results in smaller final domain sizes. A sample spot with these smaller domains gives rise to higher light scattering intensity over a wide range of scattering angles.
Distributed Asynchronous Algorithms

We consider iterative algorithms of the form x:= f(x), executed by a distributed network of processors. We first discuss a few possibilities for synchronous execution. We then consider asynchronous implementations whereby each processor iterates on a different component of x, at its own pace, using the most recently received (but possibly outdated) information on the remaining components of x. While certain algorithms may fail to converge when implemented asynchronously, a large number of positive convergence results is available. We classify asynchronous algorithms into three main categories, depending on the amount of asynchroniam they can tolerate and survey the corresponding convergence results.
Selection of Genetic Variants of Simian Immunodeficiency Virus in Persistently Infected Rhesus Monkeys

Genetic and antigenic variation may be one means by which lentiviruses that cause AIDS avoid elimination by host immune responses. Genetic variation in the envelope gene (env) was studied by comparing the nucleotide sequences of 27 clones obtained from two rhesus monkeys infected with molecularly cloned simian immunodeficiency virus. All 27 clones differed from each other and differed from the input clone in the gp120 (SU) portion of the envelope gene. Nucleotide substitutions were shown to accumulate with time at an average rate of 8.5 per 1,000 per year in SU. Surprisingly, the majority of nucleotide substitutions (81%) resulted in amino acid changes. Variation in SU was not random but occurred predominantly in five discrete regions. Within these variable regions, a remarkable 98% of the nucleotide substitutions changed the amino acid. These results demonstrate that extensive sequence variability accumulates in vivo after infection with molecularly cloned virus and that selection occurs in vivo for changes in distinct variable regions in env.
Separation and Characterization of Biomolecules Based on Macroscopic Properties

In Chapter 2 the importance of identifying the components in a system was introduced. A component may be distinguished because of certain characteristic properties that allow them to be separated from each other and then uniquely identified. Among the most useful macroscopic properties of a specific element within a system are its characteristic motions when subjected to either a constant or an accelerating force field. This often allows both separation and concurrent characterization. There are a variety of motions that are commonly encountered in biophysical separations. We will briefly describe several of these; first motion affected by normal, frictional, buoyant, and drag forces and then methods of inducing motion by means of applying acceleration forces.
MOMENTUM BUDGET AND SHELTER MECHANISM OF BOUNDARY-LAYER FLOW NEAR A SHELTERBELT

We use a nonhydrostatic shelterbelt boundary-layer turbulence model with Mellor–Yamada second-order closure to evaluate quantitatively the dynamic processes of surface boundary-layer flow perturbed by shelterbelts of different densities and to understand the shelter mechanism. We first analyze the drag exerted on air by shelterbelts of different densities, a root cause of any shelter function, and the resulting wind reduction. The results show that the effectiveness of a shelter is determined not only by its total drag but also by the distribution of the drag-generated momentum deficit in the sheltered area, and that medium-dense shelterbelts have the maximum shelter effect. We also analyze the horizontal momentum budget and find that the shelter mechanism is the product of several processes. The results reveal that strong vertical mean transport and the pressure gradient also play important roles in shelter efficiency. The pressure perturbation caused by the shelter extends far downstream of the shelter, and combines with advective transport to provide the larger shelter efficiency of medium-dense shelterbelts. We finally analyze the changes of perturbed pressure, turbulence, and vertical velocity with shelterbelt density to further clarify the shelter mechanism.
D-microgeiger: a microfabricated beta-particle detector with dual cavities for energy spectroscopy

This paper reports on micromachined Geiger counters fabricated from stacks of glass and Si wafers. As a beta particle passes through, a bias applied between two enclosed electrodes generates electron cascades in the gas between them. This results in a current pulse or "count". A single die of 2 cm/sup 2/ had 6 independent chambers ranging in size from 8/spl times/8 mm/sup 2/ to 1/spl times/3 mm/sup 2/. Helium and neon, which have different voltage bias requirements, were separately evaluated as background gases. In tests the device was found to detect incident beta particles from a Uranium-238, and calibrated /sup 90/Sr, /sup 60/Co, and /sup 204/T1 sources, of 0.1-1 /spl mu/Curie strength. In the D-microGeiger incident beta particles pass through two independent cavities that are separated by a glass barrier, which provides calibrated energy absorption. By comparing the counts in the two cavities, information about the energy of the radiation is determined. This provides an inherent ability to discern the chemical nature of the isotope, not just the presence of radiation.
The Impact of Prior Radiation Therapy on Artificial Urinary Sphincter Device Survival.

Purpose: The literature on artificial urinary sphincter device survival in individuals with a history of radiation therapy is conflicting. We assess device survival outcomes among individuals after prior radiation therapy exposure undergoing primary artificial urinary sphincter placement.Materials and Methods: An institutional review board approved database of all patients who underwent artificial urinary sphincter surgery from 1999 to 2011 was used to assess device survival in patients treated with radiotherapy compared to individuals without radiotherapy exposure. Hazard regression and competing risk analysis were used to determine the association between radiation therapy and device outcomes.Results: From 1999 to 2011 a total of 872 patients underwent artificial urinary sphincter surgery at our institution. Of these patients 489 underwent primary artificial urinary sphincter placement, with 181 of 489 (37%) having received radiation therapy. Patients with prior radiation therapy were older (median age ...
Student Satisfaction with Field Placement

Abstract Students' perceptions of their field placements rarely are taken into account in the literature on field practicum and supervision. This survey of MSW students at a southern university examines factors associated with student satisfaction with field agency, field instructor, and field learning. The survey covers student and agency characteristics, learning goals and structure, supervision, and school-agency linkages. Students associated the quality of supervision and relevance of learning most highly with satisfaction in their placement experiences. Being treated as a professional in the agency, school-agency linkages, student characteristics, and amount of time engaged in specific social work activities were found not to be major factors in student satisfaction with field work.
Mass and physical dimensions of two distinct populations of paired helical filaments

We studied the ultrastructure of two fractions of paired helical filaments (PHF) from Alzheimer brains separated on sucrose density gradient. Fraction A2 (1M sucrose) contained filaments which were short in length and did not aggregate while those in fraction AL2 (1/1.5 M sucrose interface) were mostly aggregated. By scanning transmission electron microscopy, PHF in fraction A2 had significantly more mass per nm length of filament (107-120 kD/nm) than those in fraction AL2 (79-85 kD/nm), and they were also wider in their maximum and minimum widths but did not differ in their periodicity. Differences in mass and dimensions between two morphologically distinct populations of PHF suggest that a partial proteolysis may be involved in the generation of the aggregated population of PHF. The results suggest that a similar process may be active in the formation of neurofibrillary tangles.
DNA ploidy analysis of mucinous cystic tumors of the pancreas. Correlation of aneuploidy with malignancy and poor prognosis.

BACKGROUND Benign and malignant pancreatic mucinous tumors differ in proliferative activity, production of tumor markers, and expression of growth factors. DNA ploidy is a useful index of aggressiveness and poor survival in ductal adenocarcinoma, but has not been studied in pancreatic cystic tumors. METHODS The DNA ploidy status of Fuelgen-stained tissue sections of pancreatic mucinous cystic tumors was evaluated by image cytometry and related to clinical outcome obtained by case record review. RESULTS Ploidy status correlated with malignancy and poor clinical outcome. All benign mucinous cystadenomas (n = 13) were diploid and cured by resection. Patients with diploid cystadenocarcinomas (n = 6) had an 83% survival rate following resection, while patients with aneuploid cystadenocarcinomas (n = 5) all died (four of disease and the fifth of another cause). The difference in survival between the diploid and aneuploid carcinomas was significant (P = 0.04). CONCLUSIONS DNA ploidy status of pancreatic mucinous tumors by image analysis provides quantifiable information that may be predictive of clinical outcome. DNA aneuploidy appears to be a significant differential factor in pancreatic mucinous tumors and is associated with shortened survival in mucinous cystadenocarcinomas. Cancer 1996;77:58-62.
Got glass? Glass from sediment and foraminifera tests contribute clues to volcanic history

Volcanic glass fragments recovered from sediment collected in the Escanaba Trough and on traverses up the west walls at two locations on the Gorda Ridge greatly extend information on the petrologic diversity of the region obtained from outcrops. Compositions of glass grains found loose in sediments or agglutinated in the tests of benthic foraminifers provide information on compositions of unexposed flows that were covered by later eruptions and/or sediment. Many of the glass grains have compositions that closely match those of lava outcrops, indicating that they formed by spalling off pillow rims and quench granulation. Bubble-wall glass shards found only in the sediment give evidence of explosive eruptions that occurred despite great depth. Some of the glass fragments from the walls of the axial valley have unusually high K 2 O (to >0.7%) that is not represented by any sampled outcrop. Such enriched mid-oceanic-ridge basalt compositions have not previously been reported from the Gorda Ridge. Analyzing glass grains from the sediment in addition to rims of lava samples allows a more comprehensive characterization of the volcanic history of the region.
Rapid detection of Salmonella enteritidis and Escherichia coli using surface plasmon resonance biosensor

The Biacore surface plasmon resonance (SPR)-based biosensor was used to detect Salmonella enterica serovar Enteritidis and Escherichia coli in spiked skim milk using specific antibodies. The optical SPR biosensor registers changes in the refractive index during binding of the analyte (bacteria) to the ligand (antibody) on the gold-coated sensor chip surface. Immobilized protein A-captured specific antibodies were used to detect the bacteria in less than an hour. The reaction was found to be specific, and the limits of detection of the assay were found to be 25 cfu/mL for E. coli and 23 cfu/mL for Salmonella. Because the assays were shown to be sensitive, reproducible and very specific, the SPR-based Biacore biosensor has the potential for near real-time, yet specific, detection and presumptive identification of bacteria in food and water.
Partial characterization of a Saccharopolyspora isolated from a preserved lab dissection specimen

Abstract A microorganism that initially resembled a fungus was observed growing on preserved cat dissection specimen in the Fort Hays State University anatomy laboratory. A sample of this organism was collected with a sterile swab and streaked for isolation on tryptic soy agar. The resulting colonies were subcultured numerous times until an axenic culture was obtained. Characterization of the organism by 16S rRNA gene sequencing, fatty acid methyl ester analysis, and scanning electron microscopy suggested the organism is most likely a previously undescribed member of the bacterial genus Saccharopolyspora.
Computing as if infrastructure mattered

Understanding the technical and social fundamentals of the computing infrastructure is essential in the continuously evolving technological realm.
The effect of neutron irradiation on the fracture toughness of graphite

Abstract As a part of our irradiated graphite recycle program a small quantity of PCEA grade graphite was irradiated in the High Flux Isotope Reactor (HFIR) at ORNL. The graphite will provide the “raw material” for future recycle experiments. The geometry of the irradiated graphite allowed us to study the effects of neutron irradiation on the critical stress intensity factor, K Ic , of graphite. The specimens were irradiated in two groups of 6 at an irradiation temperature of 900 °C in “rabbit” capsules to doses of 6.6 and 10.2 dpa, respectively. Following a full suite of pre- and post-irradiation examination, which included dimensions, mass, electrical resistivity, elastic constants, and thermal expansion (to 800 °C) the samples were notched and tested to determine their K Ic using the newly approved ATSM test method for SENB fracture toughness of graphite. Here we report the irradiation induced changes in the dimensions, elastic constants, resistivity, and coefficient of thermal expansion of PCEA graphite. Moreover, irradiation induced changes in the critical stress intensity factor, K Ic , or fracture toughness, are reported and discussed. Very little work on the effect of neutron irradiation on the fracture toughness of graphite has previously be performed or reported.
Social media and the public interest

This article seeks to identify the basic contours of how the notion of the public interest is taking shape in the realm of social media. Drawing upon social media governance discourse and research on the dynamics of how social media platforms are being used in the dissemination and consumption of news and information, this article argues that a restrictive and individualist model of the public interest characterizes the social media space. This article then considers the broader implications of this emergent model of the public interest in social media governance.