cssi/SciSciGPT-SciSciNet huggingface dataset:
Preparation, Ignition, and Combustion of Mg·S Reactive Nanocomposites

ABSTRACTElemental magnesium and sulfur powders were ball milled to prepare a nanocomposite material, Mg·S. Ignition of the prepared powder was characterized using both a heated filament experiment and electric spark. Combustion of individual particles was studied by injecting the powder into a premixed hydrocarbon-air flame. Combustion of powder clouds was examined using a constant volume explosion chamber. Biocidal effect of the produced combustion products against aerosolized endospores of Bacillus thuringiensis (simulant of Bacillus anthracis) was quantified. The powders ignited at lower temperatures, compared to pure magnesium. Delayed ignition was observed for powders initiated by spark and for powder clouds ignited in a constant volume chamber by a heated wire. The delay is likely due to the formation of an evaporated sulfur cloud preceding ignition. The composite material burned faster than pure magnesium, which was shown by shorter measured burn times for individual particles, and by higher rates ...
Zero-Direct-Carbon-Emission Aluminum Production by Solid Oxide Membrane-Based Electrolysis Process

A zero-direct-carbon-emission solid oxide membrane (SOM) electrolysis process was designed and developed to produce high purity aluminum metal. An inert anode assembly containing liquid silver in a one-end-closed YSZ (yttria-stabilized zirconia) membrane tube and LSM (La0.8Sr0.2MnO3-δ)-Inconel inert anode current collector was immersed in an alumina containing molten fluoride flux. A proof-of-concept electrolysis experiment was performed to confirm the aluminum production by depositing liquid aluminum directly on a TiB2 cathode. An improved setup employing liquid aluminum cathode was subsequently used to produce high purity aluminum using the SOM electrolysis process. The membrane stability was confirmed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. High purity aluminum (>99wt%) was produced and collected after the electrolysis.
Mechanical Properties of Composite AP/HTPB Propellants Containing Novel Titania Nanoparticles

Modern chemical synthesis techniques have allowed for improved incorporation of nano-scale additives into solid propellants. Various methods were implemented to incorporate titania nanoparticles into three representative ammonium perchlorate composite propellants (APCP), and the mechanical properties of each formulation were tested and compared to those of an analogous baseline. Advanced imaging techniques were applied to all particle synthesis methods to characterize particle size and particle network type and size. Uniaxial tensile testing was performed to measure propellant ultimate strength, ductility, and elastic modulus. In general, the addition of nano-titania additives to the propellant decreased propellant strength and modulus, but improved ductility. Propellant formulations containing in-situ titania exhibited an increase in ductility of 11 %, 286 %, and 186 % with a corresponding reduction in strength of 82 %, 52 %, and 17 % over analogous baselines. These trends corresponded to a simultaneous decrease in propellant density, indicating that when implementing nano-sized additives, care must be taken to monitor the effect of the altered manufacturing techniques on propellant physical properties in addition to just monitoring burning rates. Tailoring of propellant manufacturing procedures and the addition of Tepanol bonding agent to an in-situ APCP formulation fully recovered the propellant density and ultimate strength while retaining the enhanced ductility.
Abstract 18770: Elucidation of MRAS-Mediated Noonan Syndrome With Cardiac Hypertrophy

Introduction: Noonan syndrome (NS) is an autosomal dominant disorder with a characteristic clinical phenotype of facial dysmorphisms, short stature, and congenital heart defects. NS is a member of a family of developmental disorders termed “Rasopathies”, caused mainly by gain-of-function mutations in genes encoding RAS-mitogen-activated protein kinase (MAPK) signaling pathway proteins. Methods: Whole exome sequencing (WES) and trio-based genomic triangulation was performed on a 15-year old, female with a clinical diagnosis of NS and concomitant cardiac hypertrophy and her unaffected parents. Sequencing data was analyzed using Golden Helix VarSeq software with appropriate filters to identify rare, de novo variants or those inherited in a compound heterozygous or homozygous recessive manner. Homology-based modeling and molecular dynamic simulations (MDS) were performed for wildtype (WT) MRAS and the G23V-MRAS variant. Comparative analyses measured changes in bonding patterns, root-mean-square deviation (RMSD), and root-mean-square fluctuation (RMSF). A subsequent cohort analysis was performed and 110 phenotype-positive, genotype-negative NS patients were sequenced for additional NS-associated mutations in MRAS . Results: Following analysis and filtering, WES identified 176 candidate variants in 67 genes, and subsequent gene ranking identified MRAS (G23V) as the most likely novel NS-susceptibility gene. MRAS- encoded RAS-related protein 3 (MRAS) interacts directly with the MAPK pathway via SHOC2 and PP1. Molecular modeling, in silico mutagenesis, and MDS indicate that G23V-MRAS impacts effector interaction regions and the GTP binding site, supporting the notion that G23V-MRAS is an activated form of MRAS, akin to the established activating mutations at G13 in MRAS’ paralogue HRAS . Subsequent cohort analysis identified an additional rare, de novo T68I-MRAS missense mutation in a female NS patient. Conclusions: Herein, with the discovery of a two de novo variants (G23V and T68I) identified by WES or direct DNA sequencing, we have established MRAS as the newest NS-susceptibility gene. MRAS plays a crucial role in the NS-associated Ras/MAPK pathway and interacts directly with several previously identified NS-associated proteins.
A cluster-randomized trial of a middle school gender violence prevention program: Design, rationale, and sample characteristics

Abstract Introduction High rates of adolescent relationship abuse (ARA) and sexual violence (SV) reported among adolescents point to the need for prevention among middle school-age youth. This is a cluster randomized controlled trial to test an athletic coach-delivered ARA/SV prevention program in 41 middle schools (38 clusters). Trained coaches talk to their male athletes about 1) what constitutes harmful vs. respectful relationship behaviors, 2) dispelling myths that glorify male sexual aggression and promoting more gender-equitable attitudes, and 3) positive bystander intervention when aggressive male behaviors toward females are witnessed. Methods A total of 973 male athletes (ages 11–14, grades 6–8) are participating. Athletes complete surveys at the beginning and end of sports season (Time 2), and one year later (Time 3). The primary outcome is an increase in positive bystander behaviors (i.e., intervening in peers' disrespectful or harmful behaviors); secondary outcomes are changes in recognition of what constitutes abusive behavior, intentions to intervene, and gender equitable attitudes (Time 2 and 3) as well as reduction in abuse perpetration (Time 3). Results Participating schools have a greater proportion of non-White students and students on free/reduced lunch compared to schools that declined participation. Participants' self-reported ethnicities are 54.5% White, 29.0% Black, 1.4% Hispanic and the remainder, multi-racial, other, or not reported. Conclusions This study will evaluate the effectiveness of a coach-delivered ARA/SV prevention program for middle school male athletes. Findings will add to the evidence base regarding developmentally appropriate violence prevention programs as well as the role of coaches in adolescent health promotion. Clinical Trials #: NCT02331238
MIMO identification techniques in online measurement of bus impedance of interconnected power-electronics systems

Bus impedance is an important parameter for stability analysis and control design of interconnected power-electronics systems that consist of multiple power converters. This paper presents an online multi-input-multi-output (MIMO) measurement method to monitor the bus impedance of a medium-voltage DC (MVDC) distribution system on an all-electric ship. The method is based on Fourier techniques and simultaneous injection of orthogonal perturbations using existing converters. The method overcomes limitations of previously presented measurement techniques, which require several measurement cycles to obtain the bus impedance in order to avoid crosstalk among measurements. The presented approach can be used for system state monitoring and for control adaptation. Experimental results are presented and used to demonstrate the effectiveness of the proposed method.
Turbulence in vertically averaged convection

Abstract The vertically averaged velocity of the 3D Rayleigh–Benard problem is analyzed and numerically simulated. This vertically averaged velocity satisfies a 2D incompressible Navier–Stokes system with a body force involving the 3D velocity. A time average of this force is estimated through time averages of the 3D velocity. Relations similar to those from 2D turbulence are then derived. Direct numerical simulation of the 3D Rayleigh–Be nard is carried out to test how prominent the features of 2D turbulence are for this Navier–Stokes system.
Multienzyme Immobilized Polymeric Membrane Reactor for the Transformation of a Lignin Model Compound

We have developed an integrated, multienzyme functionalized membrane reactor for bioconversion of a lignin model compound involving enzymatic catalysis. The membrane bioreactors were fabricated through the layer-by-layer assembly approach to immobilize three different enzymes (glucose oxidase, peroxidase and laccase) into pH-responsive membranes. This novel membrane reactor couples the in situ generation of hydrogen peroxide (by glucose oxidase) to oxidative conversion of a lignin model compound, guaiacylglycerol-β-guaiacyl ether (GGE). Preliminary investigation of the efficacy of these functional membranes towards GGE degradation is demonstrated under convective flow mode. Over 90% of the initial feed could be degraded with the multienzyme immobilized membranes at a residence time of approximately 22 s. GGE conversion product analysis revealed the formation of oligomeric oxidation products upon reaction with peroxidase, which may be a potential hazard to membrane bioreactors. These oxidation products could further be degraded by laccase enzymes in the multienzymatic membranes, explaining the potential of multi enzyme membrane reactors. The multienzyme incorporated membrane reactors were active for more than 30 days of storage time at 4 °C. During this time span, repetitive use of the membrane reactor was demonstrated involving 5–6 h of operation time for each cycle. The membrane reactor displayed encouraging performance, losing only 12% of its initial activity after multiple cycles of operation.
A pilot study on the effect of oclacitinib on epicutaneous sensitization and transepidermal water loss in a colony of atopic beagle dogs

Background Dogs with atopic dermatitis are prone to sensitization to environmental allergens due to increased skin permeability; the effect of treatments on epicutaneous sensitizations is unknown. Hypothesis/objectives To evaluate if oclacitinib (i) prevents new sensitizations and (ii) affects skin barrier function. Animals Atopic beagle dogs. Methods Aim 1. Ten dogs were randomly assigned to placebo or oclacitinib while exposed epicutaneously to a novel allergen. Sensitization was assessed using serum allergen-specific IgE and clinically by development of skin reactions at the site of allergen application. Time to develop dermatitis and allergen-specific IgE were compared between groups. Aim 2. Eight dogs were randomly assigned to placebo or oclacitinib for four weeks and challenged with an allergen known to trigger flares. After a four week wash-out, dogs were crossed-over and the protocol repeated. Transepidermal water loss (TEWL) was measured on days 0 and 28 of each arm. Results Aim 1. Oclacitinib significantly increased (P = 0.006) time to develop skin reactions compared to placebo. Four (of five) dogs receiving oclacitinib failed to develop skin reactions, whereas all placebo dogs developed dermatitis. There were no significant differences in allergen-specific IgE between groups. Aim 2. TEWL results were difficult to interpret. Significantly higher values were detected from the axilla in placebo compared to oclacitinib-treated dogs (P = 0.047). TEWL values were significantly higher from the inguinal area in oclacitinib (P = 0.039) treated dogs but not placebo at the end of the study. Conclusions and clinical importance Clinically, oclacitinib delayed development of dermatitis at the site of allergen application. TEWL results were difficult to interpret and additional studies are required for clarification.
Characteristics of Droplet Pinch-off in Liquid/Liquid Jet Systems

Natural and periodically forced jets of water/glycerin solution were examined as they flowed into an ambient of immiscible Dow Corning 200 fluid. The dynamics of jet pinch off was investigated for jet Reynolds numbers of order 50. Refractive index matching and laser induced fluorescence were employed to obtain clear images of the interface and the jet interior. Planar velocity fields were obtained by particle image velocimetry. The results showed that the pinch off mode, including whether or not satellites form, depends on the viscosity ratio, jet Reynolds number, and jet Strouhal number. Pinch off angles appear relatively insensitive to Reynolds and Strouhal number, but sensitive to the fluid viscosity ratio.
Management of Postoperative Complications: Anemia

Anemia is extremely common following hip fracture. Consistent data from randomized trials show that transfusion of less blood, with a transfusion threshold around 8 g/dL hemoglobin concentration, is preferable to a traditional threshold of 10 g/dL. Adoption of a lower threshold leads to at least equivalent clinical outcomes, with much less exposure to transfusion costs and risks. The most common complication of transfusion is circulatory overload. Future research may elucidate the optimal transfusion threshold for these elderly patients and address the specific needs of subgroups of patients, including those with acute coronary syndrome or chronic kidney disease.
Genetically Controlled Resistance to Flavivirus and Lactate-Dehydrogenase-Elevating Virus-Induced Disease

The first demonstrations that a host gene could control resistance to disease induced by an animal virus were reported independently by Lynch and Hughes (1936) and Webster and Clow (1936). Subsequently this resistance was found to be specifically directed against flaviviruses. A number of other genes which confer resistance to other types of virus infections have since been identified (Pincus and Snyder 1915; Bang 1978). Different classes of viruses vary greatly in their mode and site of replication, and it would be expected that the mechanisms of action of various resistance gene products would also differ significantly. The strict virus specificity of host genetically controlled resistance indicates that the resistance gene products interact with unique molecular events characteristic of only one type of virus. Such a specific resistance mechanism acting at the cellular level constitutes a first-line host defense mechanism. However, the phenotypic expression of resistance genes on the whole-animal level can certainly be modified by the degree of functioning of other types of host defense mechanisms.
Observations of the Relative Contributions of Waterborne and Sediment Paths to the Received Acoustic Signal

Examples of the relative contributions of waterborne and sediment paths to acoustic propagation are presented using results obtained in a recent experiment conducted off the Oregon Coast by the Naval Oceanographic and Atmospheric Research Laboratory. The spectral energy contributions of the ground and waterborne paths to the received hydrophone signal are compared for several source-receiver separations, water depths, and frequency bands. The ground path is shown to increase in significance with decreasing frequency and, in some situations, to be as efficient a propagation path as the high-frequency waterborne path.
Emotions and risk regulation

Abstract The concept of risk is often approached as if it is self-defining. Yet placing an event or activity in the category of “risk” is a categorization with consequences. Framing normatively complex problems like immigration, terrorism, or monetary crisis as risks that require regulating suggests that certain cognitive tools are best suited for analyzing them. It suggests that the problems are measurable or quantifiable, that they lend themselves to utilitarian calculus, and that they have ascertainably correct solutions that require no value judgments. This article employs emotion theory to illustrate the difficulties with approaching normatively complex areas of governmental policy through the framework of risk regulation. It argues that interdisciplinary inquiry into the role of emotion in human behavior sheds light on how risks are assessed, prioritized, and ameliorated, on how the category of risk is constructed, and on how that categorization affects the cognitive tools and approaches we bring to normatively complex problems. The article begins with a brief discussion of behavioral law and economics, which styles itself a corrective to law and economics, but which replicates its fatal flaw: its unrealistic view of human behavior. Next it turns to two more specific problems with the standard notion of risk formulation. First, the standard notion reads out the essential role of emotion in deliberation about risk regulation and overvalues top-down expert knowledge. Second, it reads out the heuristics that erase patterns and maintain the status quo. Finally, the article will focus on two illustrative case studies, the Chicago heat wave of 1995, and Hurricane Katrina.
Radiographic and Clinical Outcomes of Periprosthetic Distal Femur Fractures Treated With Open Reduction Internal Fixation.

Objectives To report outcomes and complications of periprosthetic distal femur fractures (PPDFF) treated with open reduction internal fixation (ORIF) using a plate construct, with or without endosteal augmentation. Design Retrospective Case Series. Setting One Level I trauma center and one tertiary care hospital. Patients/participants Forty patients with PPDFFs, treated by 3 surgeons, were identified using an institutional trauma registry. Thirty-two patients with 12 months of clinical and radiographic follow-up were included, and 8 patients were lost to follow-up before 12 months. Intervention All patients underwent ORIF of the PPDFF with lateral locked plating, and 11 received additional endosteal augmentation using allograft fibula. Results Thirty-two patients were available for the final follow-up. Ninety-four percent of patients achieved union at an average of 6.5 months postoperatively. Twenty-one percent of patients underwent subsequent surgery, with more than half of those being for removal of implants. Anatomic limb alignment was achieved in all cases (no malunions). Almost half of the patients required assistive devices for ambulation in the long term. Conclusions ORIF of PPDFF with direct visualization using periarticular locking plates ± endosteal strut allograft resulted in a 94% union rate and no deep infections. There was no difference in outcomes between groups treated with or without additional endosteal fibular allograft. However, these are catastrophic injuries in frail patients, and 20% of patients either died or were lost to follow-up, and almost half required an assistive device for ambulation after surgery despite restoration of limb alignment. Level of evidence Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
A Highly Isolated Dual-polarized Crossed Dipole Array Antenna for Multi-mission Applications

A crossed dipole antenna array with dual linear polarization capability is designed and fabricated. Practical techniques such as utilizing stripline structures for baluns contribute to high isolation between the two polarizations. A better than 50 dB broadside port isolation is achieved over the entire frequency range of 2.7-3 GHz. Additionally, the isolation remains below 40 dB in scanning up to ±45° in the principal planes. A very low cross-polarization level over -60 dB is achieved owing to an image configuration of elements in the array arrangement. These features along with matched copolar beams, simple structure, and ease of fabrication make the proposed antenna array an ideal candidate for multi-mission applications.
Autonomic activity during a daytime nap facilitates working memory improvement

Recent investigations have implicated the parasympathetic branch of the autonomic nervous system (ANS) in higher-order executive functions. These actions are purported to occur through ANS modulation of the prefrontal cortex, with parasympathetic activity during wake associated with working memory ability (WM). Compared with wake, sleep is a period with substantially greater parasympathetic tone. Recent work has reported that sleep may also contribute to improvement in WM. Here, we examined the role of cardiac parasympathetic activity during sleep on WM improvement in healthy young adults. Participants were tested in an operation span task (OSpan) in the morning and evening, and during the inter-test period subjects either experienced a nap or wake. We measured high frequency heart rate variability (HF HRV) as an index of cardiac, parasympathetic activity during both wake and sleep. Participants showed the expected boost in parasympathetic activity during nap, compared with wake, as well as greater WM improvement after a nap compared with an equivalent period awake. Furthermore, parasympathetic activity during sleep, but not wake, was significantly correlated with WM improvement. Together these results indicate that the natural boost in parasympathetic activity during sleep has substantial benefits to gains in prefrontal executive function in young adults. We present a conceptual model illustrating the interaction between sleep, autonomic activity, and prefrontal brain function, and highlight open research questions that will facilitate understanding of the factors that contribute to executive abilities in young adults, as well as in cognitive aging. Keywords: nap; working memory; heart rate variability; parasympathetic; autonomic; sleep
Bacterial Load of Virtual Reality Headsets

As commodity virtual reality (VR) systems become more common, they are rapidly gaining popularity for entertainment, education, and training purposes. VR utilizes headsets which come in contact with or close proximity to the user’s eyes, nose, and forehead. In this study, the potential for these headsets to become contaminated with bacteria was analyzed. To the best of our knowledge, this study is the first to address the potential for microorganisms to be transmitted via VR headsets. The data discussed herein were collected roughly one year prior to the outbreak of the COVID-19 pandemic in the United States. We feel it is important to be clear that this study focuses exclusively on bacteria, as opposed to viruses like those responsible for the present pandemic. The nosepieces and foreheads of two HTC Vive headsets were sampled over the course of a seven-week period in a VR software development course. Serial dilutions were performed, and samples were plated on various culture media. Following incubation, counts of bacteria were determined. DNA was extracted from bacterial colonies and the 16S rRNA gene was sequenced to identify bacterial contaminates present on the headsets. Chief among these contaminates was Staphylococcus aureus. The results of these tests indicated that the Staphylococcus aureus strains isolated from the headsets possessed high levels of antibiotic resistance. Other notable bacterial isolates included Moraxella osloensis, the bacteria responsible for foul odors in laundry and, Micrococcus luteus, a communalistic bacterial species capable of causing opportunistic infections. Other bacterial isolates were detected in variable amounts throughout the trial.
Associations between maternal obesity, gestational cytokine levels and child obesity in the NEST cohort.

Background Although maternal systemic inflammation is hypothesized to link maternal pre-pregnancy obesity to offspring metabolic dysfunction, patient empirical data are limited. Objectives In this study, we hypothesized that pre-pregnancy obesity alters systemic chemo/cytokines concentrations in pregnancy, and this alteration contributes to obesity in children. Methods In a multi-ethnic cohort of 361 mother-child pairs, we measured prenatal concentrations of plasma TNF-α, IL-6, IL-8, IL-1β, IL-4, IFN-γ, IL-12 p70 subunit, and IL-17A using a multiplex ELISA and examined associations of pre-pregnancy obesity on maternal chemo/cytokine levels, and associations of these cytokine levels with offspring body mass index z score (BMI-z) at age 2-6 years using linear regression. Results After adjusting for maternal smoking, ethnicity, age, and education, pre-pregnancy obesity was associated with increased concentrations of TNF-α (P = .026) and IFN-γ (P = .06). While we found no evidence for associations between TNF-α concentrations and offspring BMI-z, increased IFN-γ concentrations were associated with decreased BMI-z (P = .0002), primarily in Whites (P = .0011). In addition, increased maternal IL-17A concentrations were associated with increased BMI-z in offspring (P = .0005) with stronger associations in African Americans (P = .0042) than Whites (P = .24). Conclusions Data from this study are consistent with maternal obesity-related inflammation during pregnancy, increasing the risk of childhood obesity in an ethnic-specific manner.
Diagenetic Facies Classification in the Arbuckle Formation Using Deep Neural Networks

Dissolution is a common diagenetic effect in carbonate formations. Vugs caused by dissolution significantly impact carbonate reservoir quality by affecting the porosity and permeability of the reservoir. However, without core and image logs, the identification and classification of vugs using wireline logs only is challenging, because logging tool responses reflect a mixed effect of changing mineral/fluid composition and diagenetic features. This paper presents a data-driven approach using neural networks to identify vugs and classify vug facies based on vug size. The purpose is to predict wells/intervals with limited measurements by machine learning models trained with core data from key wells. The input features for vug identification are conventional well logs (i.e., gamma ray, resistivity, neutron/density porosity, photoelectric factor, and acoustic slowness) from the Cambrian-Ordovician Arbuckle formation, Kansas. Two classification labels are used as the prediction target for the neural networks: (1) a binary vuggy index derived from nuclear magnetic resonance (NMR) measurements using a cutoff on T2 distribution, which presents the proportion of large pores over the total porosity, and (2) vug size labels from depth-by-depth core visual descriptions. A one-hidden-layer shallow neural network is compared against deep neural networks, including structures such as one-dimensional convolutional layers (1-D CNN) and long short-term memory (LSTM) layers. Results suggest that using a combination of multi-mineral analysis results and original well logs will increase the prediction accuracy of vug facies. Shallow and deep neural networks show a similar ability to identify vugs, with average accuracy of around 80%. However, to predict vug-size-based facies labels, deep neural networks outperform shallow neural networks, with overall accuracy improved by as much as 10%. The proposed method shows that deep neural networks (1-D CNN and LSTM) are reliable tools for vug facies prediction.
Clinical cold stress in calves

Severe weather related stress in young dairy calves is often unrecognized. If the calf is born in a cold, wet environment and is not dried immediately following birth, susceptibility to hypothermia is markedly increased. A negative energy balance (hypothermia) develops as a result of the calf's thin haircoat, heat loss due to evaporation, the small amount of subcutaneous fat and incomplete development of body temperature control mechanisms. Physiological deterioration occurs rapidly under these conditions.
Intergenerational Consequences of Births to Unmarried Women

Births to unmarried women have increased 10-fold, from about four percent in 1960 to 40 percent in 2018. Apart from teenagers, women of every age, race and ethnic group, and education level have contributed to this trend. A substantial literature reveals that children raised in two parent households fare better in life than those in any other household configuration. Many unmarried mothers inadvertently raise disadvantaged children, which is partly the product of low income that is common in non-traditional households. Exacerbating the effects of low income for these households are problems associated with family stress, household instability, and fewer parenting resources. The result is a tragedy for the children which also imposes high social costs. In 2020 about 20 percent of the prime age labor force, aged 25-54, was born to an unmarried woman. By 2050 it will be almost 40 percent. Their lower productivity undermines the social safety net that supports older Americans and is likely to increase the poverty rate when they retire even if Social Security benefits are sustained at the current level. High quality pre-school education programs that might improve the life chances of these children are explored as are vocational education and apprenticeship programs that target teens and young adults. Improving the marriage market might reduce the incidence of births to unmarried women. The corona-19 pandemic revealed how widespread economic insecurity is in the United States. Institutional reform that guarantees medical care, standard housing, and high quality day care for all citizens could relieve this insecurity with substantial benefits to children raised in non-traditional households.
Hydrogen binding and dissociation in MgScHn clusters (n ≤ 20)

Abstract Transition metal doped magnesium hydride solids are a leading candidate for hydrogen storage materials. In this investigation, MgScHn clusters (n = 1–20) are theoretically studied using density functional theory and Moller-Plesset perturbation theory. It is determined that hydrogen binds successively to the MgSc diatomic metal center up to MgScH13 when the cluster becomes saturated at 15.9% hydrogen by mass. In contrast to earlier predictions, we shown that for MgScH14 and larger clusters molecular hydrogen dissociates from the core cluster structure. A local minimum is observed on the potential energy surface for larger clusters where dissociated hydrogen interacts with a negatively charged hydride of the core cluster in a dipole-induced dipole intermolecular force, providing insight into the dissociation pathway in bulk magnesium hydride materials doped with transition metals. Analysis of the frontier orbitals and natural bonding analysis of these clusters support this logical dissociation pathway.
Chapter 12 Amorphous Semiconductor Superlattices

Publisher Summary This chapter describes a novel layered structure alternating between a-Si: H and a-SiNx:H with nearly atomically abrupt interfaces. Although the material is amorphous, a periodic superlattice is formed in one dimension. The superlattice leads to changes in optical and transport properties. As the a-Si:H layers are made thinner, the resistivity and the optical band gap increase, but little change is observed in the emission spectrum; however, the luminescence efficiency at room temperature increases. The larger increase in optical band gap and resistivity when the a-Si:H layer thickness is reduced from 40 to 8 A results from the confinement of electrons and holes in quantum wells. When the a-Si:H layer is thicker than 40 A, electron transfer doping from SiNx: H results in a low resistivity material with a density of defects at least one order of magnitude lower than in phosphorous-doped material of comparable resistivity.
F&E-Aktivitäten und Marktstruktur bei unternehmerischem Wettbewerb um kontinuierliche Verbesserungsinnovationen

In der modernen Industrieokonomik spielt die Oligopoltheorie eine zentrale Rolle. Das traditionelle Oligopolmodell der MikroOkonomik mit dem Output als Entscheidungsvariable der Unternehmen wird dabei variantenreich um weitere Wettbewerbsfaktoren wie Produktionskapazitat, Produktqualitat, Werbungsausgaben oder Ausgaben fur F&E erganzt (vgl. neuere industrieokonomische Lehrbucher wie z.B. Scherer 1980, Waterson 1984 oder Clarke 1985). Ein derartig erweitertes Oligopolmodell, das neben dem Output auch Innovationsaktivitaten in Form privater F&E-Ausgaben als Entscheidungsvariablen enthalt, bildet den modelltheoretischen Ausgangspunkt in diesem Kapitel. Zunachst wird in Anlehnung an die eher traditionelle Sicht (vgl. Nordhaus 1969, Kap. 2) angenommen, das die Unternehmen mittels ihrer F&E—Ausgaben aus einem stetigen Kontinuum an technologischen Verbesserungsmoglichkeiten auswahlen konnen. Die aus den Verbesserungsinnovationen resultierenden Effekte sind den Unternehmen genau bekannt — es existiert keinerlei Unsicherheit. Unter diesen Grundannahmen lassen sich einige wichtige Verbindungslinien zwischen den unternehmerischen F&E-Aktivitaten und der Markt-Struktur anschaulich aufzeigen. Im Vordergrund der Analyse steht die Neo-Schumpeter-Hypothese uber den Zusammenhang zwischen der Marktkonzentration als zentralem marktspezifischen Strukturparameter und den durch F&E-Ausgaben generierten Innovationen. In kurzfristiger Betrachtungsweise kann die Marktkonzentration als exogene Bestimmungsgrose angesehen werden.
Distributed effects of calcium ion contaminant on polymer electrolyte fuel cell performance

Abstract Distributed performance of a polymer electrolyte fuel cell (PEFC) is studied both in galvanostatic and potentiostatic mode during in-situ injection of Ca 2+ in the air stream using a segmented cell. In the galvanostatic mode, segments near the inlet are affected first by the contaminant resulting in decreased current density. At the same time, despite the presence of contaminants, current density for the other segments increases in order to maintain constant total current. In the potentiostatic mode, all segments are affected by the contaminants simultaneously and the current density in all segments decreases with time. The performance of the downstream segments is lower than the upstream segments. During both tests, the contaminant is found to precipitate on both the cathode flow field and the cathode GDL surface. As the test progresses, the contaminant penetrates into the GDL and deposits, causing mass transport losses.
Insecure Democracy: Risk, Vulnerability and Democratic Rights in Brazil

Latin American nations have undergone dramatic transitions to democracy and open markets in recent decades. Such changes have exposed citizens to high levels of economic volatility and insecurity, while at the same time expanding the possibilities for citizens to hold governments to account and to demand compensation for such hardships. Recent research indicates that even as economic insecurity has risen and social insurance programs have been retrenched, civil society in Latin America has remained relatively quiescent, with low levels of political participation. This paper tests the hypothesis that insecurity (defined as exposure to risk and lack of adequate means to hedge that risk) has a dampening effect on citizens’ propensity to engage in different forms of political life, such as attending municipal meetings and neighborhood organizations, and engaging in protest. Data from a 2009 nation-wide survey in Brazil reveal that individuals who have access to more extensive means of risk protection, all else being equal, are systematically more likely to participate actively in the more moderate and sustained forms of democratic politics, such as neighborhood associations and municipal meetings. This is not the case for protest activity, however, which is likely to entail very different calculations of risk and reward. The results of the analysis are preliminary, but indicate a sharp cleavage of insecurity that coincides with widening fault lines of political engagement in Brazil.
Replicative Hybrid of T4 Bacteriophage DNA

Hybrid density replicative T4 DNA was isolated from CsCl, sheared, and reanalyzed in CsCl. The results rule out a branched model for T4 DNA replication and confirm that T4 DNA replicates to a conventional, semiconservative, colinear hybrid.
IMRT and RapidArc commissioning of a TrueBeam linear accelerator using TG-119 protocol cases

The purpose of this study is to evaluate the overall accuracy of intensity-modulated radiation therapy (IMRT) and RapidArc delivery using both flattening filter (FF) and flattening filter-free (FFF) modalities based on test cases developed by AAPM Task Group 119. Institutional confidence limits (CLs) were established as the baseline for patient specific treatment plan quality assurance (QA). The effects of gantry range, gantry speed, leaf speed, dose rate, as well as the capability to capture intentional errors, were evaluated by measuring a series of Picket Fence (PF) tests using the electronic portal imaging device (EPID) and EBT3 films. Both IMRT and RapidArc plans were created in a Solid Water phantom (30 × 30 × 15 cm3) for the TG-119 test cases representative of normal clinical treatment sites for all five photon energies (6X, 10X, 15X, 6X-FFF, 10X-FFF) and the Exact IGRT couch was included in the dose calculation. One high-dose point in the PTV and one low-dose point in the avoidance structure were measured with an ion chamber in each case for each energy. Similarly, two GAFCHROMIC EBT3 films were placed in the coronal planes to measure planar dose distributions in both high- and low-dose regions. The confidence limit was set to have 95% of the measured data fall within the tolerance. The mean of the absolute dose deviation for variable dose rate and gantry speed during RapidArc delivery was within 0.5% for all energies. The corresponding results for leaf speed tests were all within 0.4%. The combinations of dynamic leaf gap (DLG) and MLC transmission factor were optimized based on the ion chamber measurement results of RapidArc delivery for each energy. The average 95% CLs for the high-dose point in the PTV were 0.030 ± 0.007 (range, 0.022-0.038) for the IMRT plans and 0.029 ± 0.011 (range, 0.016-0.043) for the RapidArc plans. For low-point dose in the avoidance structures, the CLs were 0.029 ± 0.006 (range, 0.024-0.039) for the IMRT plans and 0.027 ± 0.013 (range, 0.017-0.047) for the RapidArc plans. The average 95% CLs using 3%/3 mm gamma criteria in the high-dose region were 5.9 ± 2.7 (range, 1.4-8.6) and 3.9 ± 2.9 (range, 1.5-8.8) for IMRT and RapidArc plans, respectively. The average 95% CLs in the low-dose region were 5.3 ± 2.6 (range, 1.2-7.4) and 3.7 ± 2.8 (range, 1.8-8.3) for IMRT and RapidArc plans, respectively. Based on ion chamber, as well as film measurements, we have established CLs values to ensure the high precision of IMRT and RapidArc delivery for both FF and FFF modalities.
Metabolic control of urea catabolism in Chlamydomonas reinhardi and Chlorella pyrenoidosa.

Abstract In the unicellular green alga Chlamydomonas reinhardi (strain y-1), synthesis of the enzymes required for urea hydrolysis is under substrate induction control by urea and under end product repression control by ammonia. Hydrolysis of urea if effected by the sequential action of the discrete enzymes urea carboxylase and allophanate lyase, collectively called urea amidolyase. The carboxylase converts urea to allophanate in a reaction requiring biotin, adenosine 5'-triphosphate, and Mg2+. The lyase hydrolzyes allophanate to ammonium ions and bicarbonate. Neither activity is present in more than trace amounts when cultures are grown with ammonia or urea plus ammonia, or when they are starved for nitrogen for 8 h. Urea in the absence of ammonia induces both activities 10 to 100 times the basal levels. Addition of ammonia to an induced culture causes complete cessation of carboxylase accumulation and an 80% depression of lyase accumulation. Ammonia does not reduce urea uptake by repressed cells, so it does not prevent induction by the mechanism of inducer exclusion. The unicellular green alga Chlorella pyrenoidosa (strain 3 Emerson) also has discrete carboxylase and lyase enzymes, but only the carboxylase exhibits metabolic control.
The behavioral effect of cost targets on managerial cost reporting honesty

In response to recent calls for research on the role that firm communication plays in motivating managerial honesty, my study investigates whether firm communication of informal cost targets motivates managers to report their private information more honestly even though there is no financial reward associated with target attainment. Drawing from goal-setting theory, I hypothesize that the level of the cost target affects how targets influence managerial honesty by affecting how managers trade off their utility for target attainment and their utility for wealth. In order to test my predictions, I use an experimental setting in which the actual cost is randomly determined from a known distribution of costs and the cost target, when provided, is set at one of three levels (low, moderate, high) within this range. My results show that participants behave as if they derive utility from attaining the firm's informal cost target, but that the effectiveness of targets at motivating honesty depends on the target level. Specifically, moderate targets motivate greater honesty than low targets or no specific target. Further, low and high targets result in the same level of honesty as no specific target. Overall, these results suggest that firms have nothing to lose from a strategy that relies on informal target setting to communicate their cost preferences even when the firm is uncertain with respect to the distribution of costs.
Assembling and positioning latex nanoparticlesvia controlled evaporative self-assembly

By capitalizing on a simple, robust, and fast approach based on controlled evaporative self-assembly in a cylinder-on-flat geometry, two kinds of polystyrene (PS) latex nanoparticles with different diameters (i.e., D = 50 nm and 500 nm, respectively) were deposited on the Si substrate, forming ordered “coffee rings” composed of PS nanoparticles. Within a “coffee ring”, the packing of PS nanoparticles was found to be dependent upon the particle diameter. More intriguingly, when the aqueous solution of mixed two PS nanoparticles was used, “coffee rings” of small particles were positioned at the edge of three-phase contact line (D = 50 nm), followed by the adjacent deposition of large particles (D = 500 nm). These assembled deposits consisting of monolayer- or multilayer-thick latex nanoparticles over large areas may offer potential for applications in electronic devices, photonic bandgap materials, biosensors, particle sorting, and disease diagnosis.
Pulling Apart a Press-Fitted Joint:

Many locking devices consist of a rigid plug inserted into an annular cylindrical, rod-like body. In this paper, a one-dimensional model is developed for the resulting press-fit. This model assumes that the body is non-linearly elastic and is used to examine the mechanism by which the plug can be pulled from the rod-like body. Specifically, we find that this mechanism depends on a delicate balance between the pulling force, the deformed state of the rod-like body, and the friction holding the joint together. The application of the one-dimensional model to related problems involving press-fits is also discussed.
DREAMers and their families: A family impact analysis of the DREAM Act and implications for family well-being

Discourse around immigration reform largely centers on economic and national security issues and rarely mentions the well-being of families. This paper applies Family Impact Analysis (FIA) and rhetorical discourse analysis to the congressional hearings, debates, and documents surrounding the Development, Relief, and Education for Alien Minors (DREAM) Act to examine representations of immigrant families and implications for their well-being. Our analysis reveals that while the discourse in the DREAM Act and related congressional documents gives voice to undocumented children, it undermines family well-being. In particular, the Act promotes the rights of children over their parents, discourages family stability and unity, and impacts family interdependence negatively. Findings suggest that further consideration of FIA, in light of immigration reform efforts, is essential to crafting a policy that supports children and families during periods of transition.
DNA replication in soybean protoplasts and suspension-cultured cells: Comparison of exponential and fluorodeoxyuridine synchronized cultures

Cell-suspension cultures of soybean (Glycine max (L.) Merr., line SB-1) have been used to study DNA replication. Cells or protoplasts incorporate either radioactive thymidine or 5-bromodeoxyuridine (BUdR) into DNA. The DNA has been extracted as large molecules which can be visualized by autoradiography. Nuclei were isolated and lysed on slides thus avoiding degradation of DNA by a cytoplasmic endonuclease. The autoradiograms demonstrated that DNA synthesis occurs at several sites tandemly arranged on single DNA molecules separated by center to center distances ranging from 10 to 30 μm. Velocity sedimentations through alkaline gradients confirm the lengths of the replicated regions seen in autoradiograms. By using velocity sedimentation it also has been possible to demonstrate that replication proceeds by the synthesis of very small (4-6S) DNA intermediates which join to form the larger, replicon-size pieces seen in autoradiograms. Both small (4-6S) and large (20-30S) intermediates are observed in synchronized and exponential cultures. However, after synchronization with fluorodeoxyuridine (FUdR) the rate of DNA synthesis is reduced. Since the size of intermediates is not reduced by FUdR treatment, it is concluded that the slower rate of replication results from a reduction in the number of tandem replication units but not in the rate at which they are elongated. After FUdR treatment, the density analogue of thymidine, BUdR, can be substituted for almost all of the thymidine residue in DNA, resulting in a buoyant density increase (in CsCl) from 1.694 to 1.747 g/cm(3). Using this density analogue it is possible to estimate the amount of template DNA attached to new replication sites. When this is done, it can be shown that synchronized cells initiate replication at about 5,000 different sites at the beginning of S. (Each such site will replicate to an average length of 20 μm.) Use of BUdR also substantiates that at early stages of replication, very small replicated regions (<8S) exist which are separated by unreplicated segments of DNA which replicate at a later time. Most of these conclusions agree with the pattern of DNA replication established for animal cells. However, a major difference appears to be that after prolonged inhibition of soybean cell replication with FUdR, very small, as well as replicon-size intermediates accumulate when replication is restored. This indicates that regulation of replication in these cells may be different from animal cells.