cssi/SciSciGPT-SciSciNet huggingface dataset:
Cellular bioreactivity of micro- and nano-plastic particles in oysters

The global usage of plastics has increased dramatically over the last several decades. Polystyrene is the fourth most common plastic material produced annually due to its many versatile applications. Consequently, there has been a coinciding increase in polystyrene wastes, much of which makes its way into waterways and oceanic habitats. While plastic debris has been shown to adversely affect many marine species as a result of ingestion and entanglement, less is known about the cellular uptake of small-scale plastic particles (nano and micro) by marine invertebrates. In this study, we investigated the potential for uptake of polystyrene nano and micron sized beads (50nm and 3um) by the Eastern Oyster, Crassostrea virginica. This research was focused on two key issues: 1) how particle size would affect uptake by hepatopancreas (HP) cells in vitro, and 2) the difference in uptake of micron and nano particles in vivo between gill and HP tissues. This research confirmed that oysters can accumulate polystyrene beads in their tissues, especially HP tissues. Furthermore, using fluorescent deconvolution microscopy, it was observed that plastic nanoparticles exhibited a much greater propensity for intracellular accumulation in HP cells, primarily into lysosomes via endosomal pathways, indicating the potential for significant bioreactivity and sublethal impacts. While exposures of whole oysters or isolated HP cells to bare polystyrene beads did not cause any significant toxicity (acute or sublethal), nanoplastics are more likely to accumulate intracellularly and to deliver adsorbed toxins directly into cells.
Task Allocation Performance Comparison for Low Power Devices

Cognitive agents are typically utilized in autonomous systems for automated decision making. These systems interact in real time with their environment and are generally heavily power constrained. Thus, there is a strong need for a real time agent running on a low power computing platform. An autonomous agent reasons like humans and enables enhanced agent-based decision-making. The agent examined is the Cognitively Enhanced Complex Event Processing (CECEP) architecture. Task allocation is one of most time consuming and power-hungry processes within the CECEP architecture. Task allocation is a combinatorial optimization problem in the field of operations research. In the CECEP architecture, the cognitive agent performs this task allocation. This paper examines the performance of two task allocation algorithms (the greedy algorithm and the auction algorithm) that have the potential to significantly reduce the power and energy required to perform this task. Thus, it may be possible to execute complex task allocation problems on custom, portable, low power devices.
Better Sensing through Stacking: The Role of Non-Covalent Interactions in Guanine-Binding Sensors

A series of aryl-substituted naphthyridine-based sensors for 9-alkylguanine was analyzed using density functional theory and correlated ab initio methods. First, the 2-acetamido-1,8-naphthyridine b...
Towards Three-dimensional Millimeter-Wave Radar Imaging of On-the-move Targets

This paper presents our preliminary results for a three-dimensional (3D) imaging of an on-the-move target using a MIMO millimeter-wave (mm-wave) radar, which uses 9 transmitters and 12 receivers. The operating frequency of the mm-wave radar is from 70 GHz to 77 GHz. Experimental results show that the images can be created as the target under detection moves in front of the radar system, which is combined with 3D video to show the continuous movement of the target. This preliminary work paves the way towards a mm-wave imaging system that can be used at checkpoints; thus enabling on-the-move detection of potential threats, enhancing passenger's overall experience, and achieving a high scanning throughput.
Synthesis of α-Fluoro-α-amino Acid Derivatives via Photoredox-Catalyzed Carbofluorination

A mild, metal-free, regioselective carbofluorination of dehydroalanine derivatives has been developed. Alkyl radicals resulting from visible-light photoredox catalysis engage in a radical conjugate...
Growth of Dracaena marginata and Spathiphyllum ‘Petite’ in Sphagnum Peat- and Coconut Coir Dust-based Growing Media

Abstract A comparison was made of Canadian sphagnum peat (SP) and Philippine coconut (Cocos nucifera L.) coir dust (CD) as growing media components for greenhouse production of Dracaena marginata B...
Scaling constructs with semantic networks

This paper introduces a method for creating scales of constructs based on word bigram cooccurrences in natural language text. Instead of using a stop-word list to drop less useful words, we use a start-word list that enables computing the cooccurrences of only these “smart words.” In this way, we can create scales to measure communication constructs by first listing the key terms in the conceptual definition, then expanding the terms by looking up synonyms in dictionaries such as WordNet. Following this, we compute the cooccurrence network among these words with a sliding window. Next, we extract the first dimension through principal components analysis and identify the words that load most highly on the first factor. For these words, we sum the frequencies, which produces the final index for the construct. This operationalization yields index scales that have high construct validity, which contributes to external validity. Extending the procedures of classic psychometric index construction into the natural language domain avoids the biases of data based on fixed-choice questionnaires. To demonstrate the procedures for construct operationalization, we use a dataset of news stories about the BP Deepwater Horizon Gulf Oil Spill, scaling environmental uncertainty and organizational responses to it including innovation, strategic planning, and changes in organizational structure.
Ethylenediammonium-Based "hollow" Pb/Sn Perovskites with Ideal Band Gap Yield Solar Cells with Higher Efficiency and Stability

The power conversion efficiency (PCE) of halide perovskite solar cells is now comparable to that of commercial solar cells. These solar cells are generally based on multication mixed-halide perovskite absorbers with nonideal band gaps of 1.5-1.6 eV. The PCE should be able to rise further if the solar cells could use narrower-band gap absorbers (1.2-1.4 eV). Reducing the Pb content of the semiconductors without sacrificing performance is also a significant driver in the perovskite solar cell research. Here, we demonstrate that mixed Pb/Sn-based perovskites containing the oversized ethylenediammonium ( en) dication, { en}FA0.5MA0.5Sn0.5Pb0.5I3 (FA = formamidinium, MA = methylammonium), can exhibit ideal band gaps of 1.27-1.38 eV, suitable for the assembly of single-junction solar cells with higher efficiencies. The use of en dication creates a three-dimensional (3D) hollow inorganic perovskite structure, which was verified through crystal density measurements and single-crystal X-ray diffraction structural analysis as well as nuclear magnetic resonance measurements. The { en}FA0.5MA0.5Sn0.5Pb0.5I3 structure has massive Pb/Sn vacancies and much higher chemical stability than the same structure without en and vacancies. This new property reduces the dark current and carrier trap density and increases the carrier lifetime of the Pb/Sn-based perovskite films. Therefore, solar cells using { en}FA0.5MA0.5Sn0.5Pb0.5I3 light absorbers have substantially enhanced air stability and around 20% improvement in efficiency. After overlaying a thin MABr top layer, we found that the {5% en}FA0.5MA0.5Sn0.5Pb0.5I3 material gives an optimized PCE of 17.04%. The results highlight the strong promise of 3D hollow mixed Pb/Sn perovskites in achieving ideal band gap materials with higher chemical stability and lower Pb content for high-performance single-junction solar cells or multijunction solar cells serving as bottom cells.
Long-term fate of C3-7 arthrodesis: 4-level ACDF versus cervical laminectomy and fusion.

Background Cervical spondylotic myelopathy (CSM) most commonly occurs at the C3-7 levels and is successfully treated by multilevel anterior cervical discectomy and fusion (ACDF) or cervical laminectomy and fusion (CLF), but no procedure has clearly demonstrated superiority. Most prior investigations comparing approaches are limited by marked heterogeneity in the composition of the study groups. This investigation compares ACDF versus CLF surgery specifically at C3-7 in terms of long-term neurological outcome and the fate of the adjacent levels. Methods Over a twelve-year period, surgeries to treat CSM at C3-7 by ACDF or CLF were retrospectively reviewed. Demographic/clinical data were recorded, pre/postoperative modified Japanese orthopedic association scores (mJOA) were calculated, and any complications were noted. Results Of 781 cervical surgery patients, 15 underwent C3-7 ACDF and 49 CLF. There were no differences in patient characteristics or pre/postoperative mJOA scores. Mean follow-up was 52 and 44 months for the anterior and posterior groups, respectively. A complication occurred in 3/15 (21%) of the anterior and 14/49 (28%) of the posterior group. No infections occurred in ACDF patients, but there were three in CLF patients. Pseudoarthrosis occurred in two ACDF patients, neither associated with symptoms. Four in the CLF group had asymptomatic pseudoarthrosis; two others needed reoperation for kyphosis at the inferior level. Conclusions Long-term neurological improvement occurs following C3-7 ACDF and CLF to a similar degree. While not statistically significant, fewer complications, were seen following ACDF. The absence of symptomatic adjacent segment degeneration (ASD) following ACDF in this series raises a question for further study whether the statistical likelihood of ASD changes once the C3-7 levels are already fused.
VOC sensing using batch-fabricated temperature compensated self-leveling microstructures

Abstract We present the design, fabrication, and response of a low-power, polymer-based VOC sensor based on the self-leveling of mechanically leveraged structures. The device utilizes folded polymer-coated microcantilevers to achieve passive temperature compensation without the need for additional compensating sensors or electronics. We demonstrate that a self-leveling vapor sensor provides the same gas response as a simple microcantilever geometry, showing ∼20 % change in device capacitance when subjected to 35–85 %RH change while showing nearly-zero baseline drift due to changes in ambient temperature when the temperature is increased from 23−72 °C which is ∼52-fold better than a simple microcantilever geometry. The response of the VOC sensor was measured using three polymers (Polyimide, Polyurethane, and PDMS) against five different analytes (Ethanol, Acetone, Benzene, Hexane, and Water) and an SVM-based model was used to show target specificity. The sensor also showed an absorption response time (τ90) of ∼138 s. We propose that the self-leveling vapor sensor geometry is a significant improvement to a simple microcantilever vapor sensor as it offers the same performance but shows near-complete elimination of temperature-induced baseline drift.
MASSAGE THAT POCKET: A CASE OF INAPPROPRIATE SHOCKS AFTER SUBCUTANEOUS ICD PLACEMENT

Subcutaneous ICD (S-ICD) has recently emerged as an alternative to transvenous ICD. However, inappropriate ICD therapy remains a concern. A 72-year-old woman with history of heart failure with reduced ejection fraction (20-25%) presented for elective S-ICD placement for primary prevention of sudden
Negative conversion premium

Abstract We document frequent occurrences of negative conversion premium (NCP) events in the Chinese convertible bond market, when the bond is convertible and the underlying stock can be freely sold. This implies that when an NCP event occurs, existing stock holders can earn a riskless profit through a long-short strategy which sells the underlying stock and buys the convertible bond at the same time, then converts the bond into stocks. Facing short sale constraints, traders not holding any position in the underlying stock can still profit from an overnight trading strategy which buys the convertible bond at the NCP event day t, then sells the converted stock on day t + 1. We also find that the next-day opening prices following NCP events are significantly lower, which is evidence for the stock selling from the overnight trading strategy. Overall, our findings show that investors in China are aware of the NCP events and they earn abnormal returns through active trading. However, it remains as a puzzle why existing stock holders such as institutional investors do not trade away the negative conversion premium through the riskless long-short strategy.
An Adaptive Machine Learning Framework for Behind-the-Meter Load/PV Disaggregation

A significant amount of distributed photovoltaic (PV) generation is “invisible” to distribution system operators since it is behind the meter on customer premises and not directly monitored by the utility. The generation essentially adds an unknown varying negative demand to the system, which causes additional uncertainty in determining the total load. This uncertainty directly impacts system reliability, cold load pickup, load behavior modeling, and hence cost of operation. Thus, it is essential to create low-complexity localized models for estimating power generation from these invisible sites behind the meters. This article proposes an adaptive machine learning framework to: a) learn using weather data and a minimal number of BTM PV generation measurement sensors, b) forecast PV generation using weather, location of PV, and trained ML model at location for unmeasured BTM PV; c) use estimated PV and net load measured by smart meter or smart transformer to estimate total true load at each time step; and d) learn the specific load patterns eventually to adapt localized models. The proposed framework's core idea is to transform the data such that: a) the machine learning model can effectively utilize the time dependency of measurements; and b) the measurements are transformed into a lower dimensional space to reduce complexity while maintaining accuracy. The transformed measurements are then used to train the machine learning models for load/PV disaggregation. Machine learning models investigated include linear regression, decision tree, random forest (RF), and multilayer perceptron. The proposed framework's efficacy is demonstrated using two datasets, a real dataset from Hawaii and a simulated dataset using detailed models in GridLab-D. Several test/training split scenarios, including 90–10% split, one-month-out, one-season-out, and panel-independent split are presented to provide a thorough evaluation of the proposed framework. Results on both datasets show that the proposed framework can estimate PV generation with high accuracy using low-complexity methods. The accuracy results are comparable to higher complexity models (e.g., deep architectures), and RF is found to provide superior performance with these specific datasets compared to the other ML models investigated.
Ecological memory of prior nutrient exposure in the human gut microbiome

Abstract Many ecosystems retain an ecological memory of past conditions that affects responses to future stimuli. However, it remains unknown what mechanisms and dynamics may govern such a memory in microbial communities. Here, in both a human dietary intervention cohort and an artificial gut, we show that the human gut microbiome encodes a memory of past carbohydrate exposures. Changes in the relative abundance of primary degraders were sufficient to enhance metabolism, and these changes were mediated by transcriptional changes within hours of initial exposure. We further found that ecological memory of one carbohydrate species impacted metabolism of others. These findings demonstrate that the human gut microbiome’s metabolic potential reflects dietary exposures over preceding days and changes within hours of exposure to a novel nutrient. One Sentence Summary Recent nutrient exposures are encoded into the structure and activity of human gut microbial communities, which enables more efficient future metabolic responses.
Large deformation finite element analyses in TBM tunnel excavation: CEL and auto-remeshing approach

Abstract Analyzing tunnel excavation behavior involves large deformation issues. For this reason, large deformation analysis method is required to rigorously investigate the actual effect of excavation on surrounding ground. Two major numerical approaches capable of considering large deformations are applied to investigating the effect of tunnel boring machine excavation: coupled Eulerian-Lagrangian (CEL) and the automatic remeshing after small strain approach. The theoretical basis and application of the methods will be discussed before their relative performance is evaluated through the ground response due to TBM excavation. The ground response will be quantified by estimating the range of the excavation damaged zone (EDZ). By comparing the results, the range of the size of the EDZ will be suggested along the vertical and horizontal direction along the TBM advancement. Based on the computed results, it was found that the size of EDZ around the excavation surface and the tendencies was in good agreement among the two methods. Numerical results clearly show that the size of the EDZ around the tunnel tends to be bigger for harder rocks. The size of the EDZ is found to be direct proportional to the tunnel diameter, whereas the depth of the tunnel is inversely proportional due to higher confinement stress around the excavation surface.
Analyzing Quasi-Experiments: Some Implications of Assuming Continuous Growth Models

There is a large body of literature devoted to critiquing the adequacies of various approaches to analyzing data from quasi-experiments. It has slowly become clear that any discussion of approaches to analysis of quasiexperiments is incomplete unless certain assumptions are made about data resulting from growth in the absence of treatment effects. One popular assumption, and for which there exists appropriate analyses, is the fan spread hypothesis. The utility of the fan spread hypothesis for educational data is explored through relationships to a large class of continuous growth models. It is shown that the fan spread hypothesis is both more and less restrictive than past literature would suggest. Implications for data analysis are also discussed.
Observations on the Coincidence of Endocrine Dystrophies and Mental Subnormalities

Excerpt Since the now famous reports of Brown-Sequards on the results of testicular injections and transplants, and the ensuing work of other less well-known and imaginative observers, almost every...
On the dynamics of distillation processes-V: The topology of the boiling temperature surface and its relation to azeotropic distillation

Abstract It is shown that ridges and valleys in the boiling temperature surface do not coincide with azeotropic distillation region boundaries. Thus, the prevai and valleys is shown to be false. This allows for a greater flexibility in design and a better understanding of the behavior of azeotropic distillation
Biochemical Alternations in Bacillus megaterium as Produced by Aflatoxin B1

Bacillus megaterium NRRL B-1368 cells and spores were produced on Trypticase Soy Broth (TSB) and Agar (TSA) containing 3.8 μg of aflatoxin B1 per ml, analyzed for selected chemical constituents, and compared to cells and spores of B. megaterium produced on nontoxic Trypticase Soy Media. There was an initial 30% kill of cells after inoculation into toxic TSB and during the first 3.5 hr of incubation followed by a logarithmic growth phase in which the generation time was 75 min as compared to 20 min for the control culture. Chemical analyses revealed an increase in protein, deoxyribonucleic acid (DNA), and ribonucleic acid (RNA) on both a per cell basis and a per cent dry weight basis when B. megaterium was grown in toxic TSB. There was a concurrent decrease in the total amounts of cellular protein, DNA, and RNA synthesized in toxic TSB. Amino acid analyses of control and test cell walls showed little, if any, difference in cell wall composition. About 97% sporulation of B. megaterium occurred after 3 days on nontoxic TSA although 6 days were required to attain 65% sporulation on toxic TSA. Germination of spores was not inhibited by 4.0 μg of aflatoxin per ml but outgrowth was. No significant differences were observed in the heat resistance, protein, DNA, RNA, or dipicolinic acid content of spores formed on toxic TSA and nontoxic TSA.
An Alternative Model for Quantitative Trait Loci (QTL) Analysis in General Pedigrees

Summary Linkage detection of a trait involves detecting regions of the genome that influence the trait. A wide variety of statistical models are currently employed for linkage analysis of quantitative traits. Many of these models are developed under some assumptions of the trait distributions. Violation of the assumptions about the trait generally affects the type I error and power for linkage detection. In this paper, we have proposed a trait-model-free approach for linkage analysis of a quantitative trait in general pedigrees. The conditional segregation of marker alleles given the trait is modeled using a latent-variable logistic model. A likelihood-ratio test is used to test for linkage under our model. The main applicability of this approach lies in the fact that it always provides correct type I error no matter what the trait distribution is and thus can be used for nonnormal traits or for selected samples. By means of simulation studies, we have compared the power of our proposed model with existing approaches for nonnormal traits. The performance of these methods was also studied on a real dataset. We have demonstrated the usefulness of our approach in terms of power and robustness for linkage detection of quantitative traits in general pedigrees.
Mixed H/sub 2///spl mu/ performance bounds using dissipation theory

In this paper, we develop bounds for the H/sub 2/ performance of systems with uncertainty, yielding a mixed H/sub 2///spl mu/ performance criterion. Using results from dissipation theory, we show how the /spl mu/ upper bounds can be derived in terms of dissipation inequalities. This framework is extended to include an H/sub 2/ performance metric to produce an overbound on the worst case H/sub 2/ performance of a system with uncertainties. This work extends previous work in mixed H/sub 2///spl mu/ performance metrics by allowing nonequalised weights at both the input and the output, and by allowing multiple uncertainties. >
Climate index weighting of ensemble streamflow forecasts using a simple Bayesian approach

Climate state can be an important predictor of future hydrologic conditions. In ensemble streamflow forecasting, where historical weather inputs or streamflow observations are used to generate the ensemble, climate index weighting is one way to represent the influence of climate state. Using a climate index, each forecast variable member of the ensemble is selectively weighted to reflect the climate state at the time of the forecast. A new approach to climate index weighting of ensemble forecasts is presented. The method is based on a sampling-resampling approach for Bayesian updating. The original hydrologic ensemble members define a sample drawn from the prior distribution; the relationship between the climate index and the ensemble member forecast variable is used to estimate a likelihood function. Given an observation of the climate index at the time of the forecast, the estimated likelihood function is then used to assign weights to each ensemble member. The weights define the probability of each ensemble member outcome given the observed climate index. The weighted ensemble forecast is then used to estimate the posterior distribution of the forecast variable conditioned on the climate index. The Bayesian climate index weighting approach is easy to apply to hydrologic ensemble forecasts; its parameters do not require calibration with hindcasts, and it adapts to the strength of the relation between climate and the forecast variable, defaulting to equal weighting of ensemble members when no relationship exists. A hydrologic forecasting application illustrates the approach and contrasts it with traditional climate index weighting approaches. This article is protected by copyright. All rights reserved.
Rapid Focal Shifting Optics for Inline 3D Image Capture

We present a novel lens system with high-resolution and wide field-of-view for 3D image capture. A depth-from-defocus algorithm is implemented to reconstruct 3D object and matched with a fused image to create a 3D view.
Rates of convergence for the homogenization of fully nonlinear uniformly elliptic pde in random media

We establish a logarithmic-type rate of convergence for the homogenization of fully nonlinear uniformly elliptic second-order pde in strongly mixing media with similar, i.e., logarithmic, decorrelation rate. The proof consists of two major steps. The first, which is actually the only place in the paper where probability plays a role, establishes the rate for special (quadratic) data using the methodology developed by the authors and Wang to study the homogenization of nonlinear uniformly elliptic pde in general stationary ergodic random media. The second is a general argument, based on the new notion of δ-viscosity solutions which is introduced in this paper, that shows that rates known for quadratic can be extended to general data. As an application of this we also obtain here rates of convergence for the homogenization in periodic and almost periodic environments. The former is algebraic while the latter depends on the particular equation.
Minimally invasive management of scaphoid fractures

Abstract Percutaneous internal fixation of scaphoid fractures allows for more predictable union and less morbidity than cast treatment or open internal fixation. This technique is appropriate for both acute scaphoid waist and proximal pole fractures, as well as selected nonunions. A headless cannulated compression screw (standard Acutrak) is implanted via a dorsal percutaneous approach using fluoroscopy and arthroscopy to confirm position and reduction. The details of this technique are reviewed. In a consecutive series of 27 fractures treated with arthroscopic assisted dorsal percutaneous fixation, eighteen fractures were treated acutely and 9 were treated more than 1 month after injury. CT scan confirmed 100% union rate at an average of 12 weeks with no complications.
Adducts of Thianthrene- and Phenoxathiin Cation Radical Tetrafluoroborates to 1-Alkynes. Structures and Formation of 1-(5-Thianthreniumyl)- and 1-(10-Phenoxathiiniumyl)alkynes on Alumina Leading to α-Ketoylides and α-Ketols

[structure: see text] Thianthrene cation radical tetrafluoroborate (Th*+ BF4(-)) added to the terminal alkynes 1-pentyne, 1-hexyne, 1-heptyne, 1-octyne, 1-nonyne, and 1-decyne to form trans-1,2-bis(5-thianthreniumyl)alkene tetrafluoroborates (1-6). Similarly, addition of phenoxathiin cation radical tetrafluoroborate (PO*+ BF4(-)) to the same alkynes gave 1,2-bis(10-phenoxathiiniumyl)alkene tetrafluoroborates (7-12). The trans configuration of two of the adducts (1 and 4) was shown with X-ray crystallography. When solutions of 1-6 in chloroform were stirred with activated alumina, cis elimination of a proton and thianthrene (Th) occurred with the formation of 1-(5-thianthreniumyl)alkyne tetrafluoroborates (1a-6a). Similar treatment of 8-12 caused elimination of a proton and phenoxathiin (PO) with formation of 1-(10-phenoxathiiniumyl)alkene tetrafluoroborates (8a-12a). Stirring of 1a-6a with alumina for short periods of time caused their conversion into 5-[(alpha-keto)alkyl]thianthrenium ylides (1b-6b) and alpha-ketols, RC(O)CH2OH (1c-6c).
Random walks with nonnearest-neighbor transitions. II. Analytic one-dimensional theory for exponentially distributed steps in systems with boundaries

Exact analytic results for symmetric, nonnearest-neighbor random walks in one-dimensional finite and semiinfinite lattices are presented. Random walks with exponentially distributed step lengths are considered such that variation of a single parameter permits one to cover the whole range of step lengths from nearest-neighbor transitions to steps of aribtrary length. The generating functions for such lattices are derived and used to calculate a number of moment properties (mean first passage times, dispersion in the mean recurrence time). Since explicit expressions for the generating functions for these walks are obtained, additional moment properties can readily be calculated. The results found here for a finite system are compared to results found previously for a system with periodic boundary conditions. Two different semiinfinite systems are also considered.
Simulation of a chemical reaction process using GASP IV

This paper is a sequel to the preceding paper de scribing the GASP IV language. In this paper, the simulation of a chemical reaction process is used as a vehicle for illustrating the procedures for using GASP IV. The details of the computer coding as well as samples of computer output are included. The in tent of the paper is to illustrate the use of GASP IV to analyze a system involving both continuous varia bles and discrete events.
Structure of nicotinic acid mononucleotide adenylyltransferase from Bacillus anthracis

Nicotinic acid mononucleotide adenylyltransferase (NaMNAT; EC 2.7.7.18) is the penultimate enzyme in the biosynthesis of NAD+ and catalyzes the adenylation of nicotinic acid mononucleotide (NaMN) by ATP to form nicotinic acid adenine dinucleotide (NaAD). This enzyme is regarded as a suitable candidate for antibacterial drug development; as such, Bacillus anthracis NaMNAT (BA NaMNAT) was heterologously expressed in Escherichia coli for the purpose of inhibitor discovery and crystallography. The crystal structure of BA NaMNAT was determined by molecular replacement, revealing two dimers per asymmetric unit, and was refined to an R factor and R free of 0.228 and 0.263, respectively, at 2.3 A resolution. The structure is very similar to that of B. subtilis NaMNAT (BS NaMNAT), which is also a dimer, and another independently solved structure of BA NaMNAT recently released from the PDB along with two ligated forms. Comparison of these and other less related bacterial NaMNAT structures support the presence of considerable conformational heterogeneity and flexibility in three loops surrounding the substrate-binding area.
Oxygen penetration and diffusion into myoglobin revealed by quenching of zincprotoporphyrin IX fluorescence

Oxygen quenching experiments were carried out on zincprotoporphyrin IX reconstituted myoglobin (MbFe-->Zn) at different temperatures and two solvent viscosities. The data were fit to a dynamic model for quenching of fluorophores in protein interiors previously presented (Biophysical J., 45 (1984) 789-794). The parameters associated with the oxygen entry rate (k+), exit rate (k-), and migration rate (chi) in the protein were obtained at six temperatures and two viscosities (1 and 8 cp), along with the activation enthalpies associated with the above rates (k+ and k-). The partition coefficient (alpha) was calculated at each temperature along with the free energy, delta G0, associated with this partition. The rate parameters (k+, k-, chi) and the partition coefficient (alpha) have also been determined for the sample in 40% sucrose (8 cp), to evaluate the effect of bulk solvent viscosities on these values. The steady-state Stern-Volmer quenching plot was calculated using the rate parameters obtained from the analysis (of the dynamic model). Comparison of the Stern-Volmer points obtained using the dynamic model and those obtained experimentally showed excellent agreement.
Effects of temperature-induced variation in anuran larval growth rate on head width and leg length at metamorphosis.

We tested whether temperature-induced variation in the growth rate of Rana cascadae tadpoles caused any variation in head width or leg length at metamorphosis, independent of the effects of temperature on body size. Body-size-adjusted head width appears to be insensitive to even large variations in tadpole growth rate. This result mirrors previous observations on the effects of variation in food level and temperature on metric shape in frogs and other ectothermic vertebrates. Leg length, on the other hand, showed a small but statistically significant response to the temperature treatment. Fast-growing tadpoles attained slightly longer legs than slowly growing tadpoles at a common metamorphic body size. This example is the first to show that variation in growth rate per se can influence metric shape (i.e., the rate at which individuals reach a common body size determines their shape at that size). Nevertheless, the induced effects were small, and our results taken together with those of previous studies suggest that environmentally induced variation in growth rate is not a major source of variation in metric shape of skeletal characters in ectothermic vertebrates.
Analysis of crack moving and curving in anisotropic solids

Abstract The general equations for a dynamically curved crack in an anisotropic solid are derived, and the asymptotic fields of a moving crack under arbitrary distributed loading on the crack surface are calculated from them. For a moving crack under mixed-mode loading conditions a general Muskhelishvili type approach is proposed to calculate intensity factors due to crack surface loading in anisotropic materials. The kinking and curving caused by dynamic loading in anisotropic materials are calculated using the maximum normal stress ratio criterion. The results show that cracks in anisotropic solids may deviate from the straight path and approach a direction parallel to the stiff axis even under symmetric loading and that a crack will tend to deviate more from the crack path to the direction of the stiff axis as the crack speed becomes higher.
Increased Lymph Node Evaluation With Colorectal Cancer Resection: Does It Improve Detection of Stage III Disease?

Hypothesis Evaluation of 12 or more lymph nodes (LNs) with colorectal cancer (CRC) resection may not improve detection of stage III disease. Design Retrospective review after intervention. Setting Community teaching hospital. Patients We evaluated 701 consecutive operative CRC cases ascertained from our Cancer Registry. Intervention Patients undergoing resection before (n = 553) a multidisciplinary initiative emphasizing the importance of LN counts were compared with those undergoing operation afterward (n = 148). Main Outcome Measures Number of LNs evaluated, proportion of patients with stage III disease, and proportion of patients with N1 vs N2 disease. Results Demographic, tumor, and treatment variables were similar for both groups, except for younger age, fewer white patients, and more laparoscopic resections in the late period. Lymph node counts increased from a mean (SEM [median]) of 12.8 (0.3 [12]) to 17.3 (0.7 [16]) ( P P = .31). Among patients with positive LNs, the distribution of N1 and N2 disease was unchanged (early, 50.5% N1 and 49.5% N2; late, 54.2% N1 and 45.8% N2; P = .54). Conclusions Increased LN retrieval does not identify a greater number of patients with stage III CRC nor does it increase the proportion of patients with positive LNs with N2 disease. Our data suggest that harvest of at least 12 LNs as a quality or performance measure appears unfounded.
Mechanistic studies on the conjugation of methyl isocyanate with N-acetyl-cysteine in rats

In order to investigate the utility of selected thiols as scavengers of MIC, we first assessed the chemical stability of SMG, AMCC and SMC by measuring their rates of reaction in vitro with thiophan. The inital rates of carbamoylation of thiorphan (0.5 mM) by the above conjugates (0.5 mM) in aqueous buffer at pH 7.4 and 37°C were 2.51, 0.76 and 8.47 μmol L−1 min−1, respectively, indicating that the mercapturate AMCC was the most stable of the three MIC conjugates.
Ultrathin reactive metal films on TiO2(110): growth, interfacial interaction and electronic structure of chromium films

Abstract A study of ultrathin Cr films on TiO2(110) surfaces is reported. The combination of low energy ion scattering (LEIS) and X-ray photoelectron spectroscopy (XPS) enables us to study quantitatively the growth of reactive metal films on metal oxides, and the chemical interactions at the interface. Ultrathin Cr films grow initially in a quasi-two-dimensional fashion at room temperature. Changes in oxidation states of both Ti and Cr during film formation suggest that strong chemical interactions at the interface are of great importance in the growth of reactive metal films. Cr “wets” the surface more effectively at 300 K than ultrathin films of less reactive metals, Fe and Cu. This suggests that a relation exists between the metal reactivity with oxygen and the wetting of metal films on oxides: The more reactive the metal towards oxygen, the better is the wetting ability. The chemical interaction is accompanied by charge transfer at the interface, causing a reduction of the surface work function. The interfacial interaction also causes the interfacial Cr layer to behave differently from the top metallic Cr atoms upon thermal annealing. The top layers of metallic Cr show a strong clustering tendency at 500°C, while the interfacial Cr seems to have less surface mobility and slow bulk diffusion.
Hand-held forward-looking focused array mine detection with plane wave excitation

A novel handheld time-domain array GPR antipersonnel mine detection system prototype has been developed. Using an offset paraboloidal reflector antenna to collimate rays form an ultra-wideband feed, the transmitted microwave impulse is concentrated forward, in front of the antenna structure. The resulting wave is a non-uniform plane wave over the portion of ground be investigated, and is incident at 45 degrees to normal. As such, much of the ground reflect wave is directed further forward, away from the operator, the reflector, and the receiving antennas, thereby reducing clutter. However, the wave transmitted into the ground, which interacts with the target, tends to have significant backscatter returning toward the receiving antennas. These receiving antennas are configured in a 2 by 2 array to provide spatial focusing in both along and cross-track directions. This is accomplished by measuring and comparing the backscattered signal at each receiver in the narrow time window between the times when the ground reflected wave passes the receiver and before this wave re-reflects from the reflector components. 2D FDTD simulation of this parabolic reflector transmitter indicates that it generates a beam with a non-uniform planar wavefront, which scatters form rough ground primarily in the forward direction. The wave transmitted into the ground is also planar, propagating at the angle of refraction, and scattering fairly isotropically from a small penetrable target. This system has been built and tested at LLNL, using a very narrow pulse shape. LLNL's Micro-Impulse Radar (MIR) and custom-built wideband antenna elements operate in the 1.5 to 5 GHz range. One particular advantage of using the MIR module is its low cost: an important feature for mine detectors used in developing countries. Preliminary measured data indicates that the surface clutter is indeed reduced relative to the target signal, and that small non-metallic anti-personnel mines can be reliably detected at burial depths as shallow as 1 inch in both dry.
US billion-dollar weather and climate disasters: data sources, trends, accuracy and biases

This paper focuses on the US Billion-dollar Weather/Climate Disaster report by the National Oceanic and Atmospheric Administration’s National Climatic Data Center. The current methodology for the production of this loss dataset is described, highlighting its strengths and limitations including sources of uncertainty and bias. The Insurance Services Office/Property Claims Service, the US Federal Emergency Management Agency’s National Flood Insurance Program and the US Department of Agriculture’s crop insurance program are key sources of quantified disaster loss data, among others. The methodology uses a factor approach to convert from insured losses to total direct losses, one potential limitation. An increasing trend in annual aggregate losses is shown to be primarily attributable to a statistically significant increasing trend of about 5 % per year in the frequency of billion-dollar disasters. So the question arises of how such trend estimates are affected by uncertainties and biases in the billion-dollar disaster data. The net effect of all biases appears to be an underestimation of average loss. In particular, it is shown that the factor approach can result in a considerable underestimation of average loss of roughly 10–15 %. Because this bias is systematic, any trends in losses from tropical cyclones appear to be robust to variations in insurance participation rates. Any attribution of the marked increasing trends in crop losses is complicated by a major expansion of the federally subsidized crop insurance program, as a consequence encompassing more marginal land. Recommendations concerning how the current methodology can be improved to increase the quality of the billion-dollar disaster dataset include refining the factor approach to more realistically take into account spatial and temporal variations in insurance participation rates.
As we may communicate

The purpose of this article is to critique and reshape one of the fundamental paradigms of Human-Computer Interaction: the workspace. This treatise argues that the concept of a workspace---as an interaction metaphor---has certain intrinsic defects. As an alternative, a new interaction model, the communication space is offered in the hope that it will bring user interfaces closer to the ideal of human-computer symbiosis.
Dielectric core-shell optical antennas for strong solar absorption enhancement.

We demonstrate a new light trapping technique that exploits dielectric core–shell optical antennas to strongly enhance solar absorption. This approach can allow the thickness of active materials in solar cells lowered by almost 1 order of magnitude without scarifying solar absorption capability. For example, it can enable a 70 nm thick hydrogenated amorphous silicon (a-Si:H) thin film to absorb 90% of incident solar radiation above the bandgap, which would otherwise require a thickness of 400 nm in typical antireflective coated thin films. This strong enhancement arises from a controlled optical antenna effect in patterned core–shell nanostructures that consist of absorbing semiconductors and nonabsorbing dielectric materials. This core–shell optical antenna benefits from a multiplication of enhancements contributed by leaky mode resonances (LMRs) in the semiconductor part and antireflection effects in the dielectric part. We investigate the fundamental mechanism for this enhancement multiplication and de...
Study of amorphous Ta 2 O 5 thin films by DC magnetron reactive sputtering

The dc magnetron reactive sputtering deposition of tantalum pentoxide (Ta2O5) thin films was investigated. By combining Schiller's criterion and Reith’s “target preoxidation” procedure, high quality Ta2O5 thin films were prepared at a high deposition rate of about lOOA;/min. The deposited films were amorphous, with a refractive index around 2.07 and a dielectric constant of 20. An optical transmit-tance of 98.6% was obtained for a 4500Â thick film. The leakage current density is 5 × 10−9 A/cm2 at an electric field strength of 1 MV/cm and its breakdown field strength is above 2 MV/cm. The temperature coefficient of capacitance for capacitors fabricated using the deposited films is approximately +230 ppm/°C. X-ray photoelectron spectroscopy shows that the films are stoichiometric tantalum pentoxide, Ta2O5, and exhibit good stability.
Simple Manufacturability Estimates for Optical Aspheres

The difficulty of fabricating an asphere is typically related to the difference between the local principal curvatures over its surface. Manufacturability estimates are derived by tailoring methods for estimating the rms of this difference.
Optical reflectance of graphite intercalated with group V pentafluorides

Abstract Stage 1–4 compounds of HOPG intercalated with SbF 5 and AsF 5 were carefully prepared and characterized. Optical reflectance was measured from 0.07 to 2.0 eV using in situ techniques; such methods were necessary because surface decomposition always occurred when samples were transferred to an environment lacking a partial pressure of the intercalate. Although the reaction characteristics were profoundly different, the general behaviour of the SbF 5 and AsF 5 compounds was similar. Detailed measurements of AsF 5 compounds during intercalation displayed the emergence of metallic reflectance well within the dilute limit [8], consistent with a downward shift of E F in a rigid band approximation. Spectra for stage 1 and 2 compounds exhibit simple metallic behavior. However, the best fits to the overall spectra were obtained by including a small dispersionless interband contribution. For the AsF 5 compounds σ opt = ω p 2 τ 4π is in good agreement with σ dc ; for SbF 5 the comparison cannot be drawn as clearly, but σ opt and σ dc are still comparable [3]. Several observations indicated that dilute AsF 5 compounds are more stable in air than the corresponding SbF 5 compounds. For stage 1 and 2, both materials decomposed rapidly in air, accompanied by gross exfoliation and emission of fumes of white solids. Dilute compounds of both types were more stable; the IR reflectance remained high, but the plasma edge broadened drastically. After 1 000 h, stage 4 SbF 5 exhibited a 10% weight loss and complete disappearance of the c -axis superlattice diffraction, implying conversion to a residue compound. Conversely, stage 3 AsF 5 left in air for 1 000 h exhibited no weight loss, no degradation of the X-ray pattern, and no decrease in σ a ( i.e. , σ a remained comparable with that of copper).
High-resolution Fourier transform infrared spectroscopy of the NS radical

Extension des mesures pour v=0 et v=1 de l'etat X 2 Π a des valeurs de J plus elevees, permettant une determination plus precise des constantes moleculaires
On the Mean Flow Induced by a Thermal Wave

Abstract The problem of the motion induced by a sinusoidal thermal wave propagating in a horizontal layer of fluid is investigated in the limit of small Prandtl number. An exact solution of the nonlinear equations is derived in a special case. The mean flow corresponding to this particular solution is vanishing for all values of the wavenumber, the phase speed, and the amplitude of the wave. More general solutions with non-vanishing mean flow are obtained by a perturbation approach based on the exact solution. In addition it is found that mean flows of either sign occur in the form of an instability, even in the case when the temperature field is stationary.
Human herpesvirus replication and abnormal CD8+ T cell activation and low CD4+ T cell counts in antiretroviral-suppressed HIV-infected patients.

Background Most HIV-infected patients receiving virologically suppressive antiretroviral therapy continue to have abnormal, generalized T cell activation. We explored whether the degree of ongoing cytomegalovirus (CMV), Epstein-Barr virus (EBV) and Kaposi's sarcoma herpesvirus (KSHV) replication was associated with higher virus-specific T cell activation and the failure to achieve normal absolute CD4+ T cell counts in the face of long-term suppressive antiretroviral therapy.