cssi/SciSciGPT-SciSciNet huggingface dataset:
Decreasing the Lag Between Result Availability and Decision-Making in the Emergency Department Using Push Notifications.

Author(s): Koziatek, Christian; Swartz, Jordan; Iturrate, Eduardo; Levy-Lambert, Dina; Testa, Paul | Abstract: Introduction: Emergency department (ED) patient care often hinges on the result of a diagnostic test. Frequently there is a lag time between a test result becoming available for review and physician decision-making or disposition based on that result. We implemented a system that electronically alerts ED providers when test results are available for review via a smartphone- and smartwatch- push notification. We hypothesized this would reduce the time from result to clinical decision-making.Methods: We retrospectively assessed the impact of the implementation of a push notification system at three EDs on time-to-disposition or time-to-follow-up order in six clinical scenarios of interest: chest radiograph (CXR) to disposition, basic metabolic panel (BMP) to disposition, urinalysis (UA) to disposition, respiratory pathogen panel (RPP) to disposition, hemoglobin (Hb) to blood transfusion order, and abnormal D-dimer to computed tomography pulmonary angiography (CTPA) order. All ED patients during a one-year period of push-notification availability were included in the study. The primary outcome was median time in each scenario from result availability to either disposition order or defined follow-up order. The secondary outcome was the overall usage rate of the opt-in push notification system by providers.Results: During the study period there were 6115 push notifications from 4183 ED encounters (2.7% of all encounters). Of the six clinical scenarios examined in this study, five were associated with a decrease in median time from test result availability to patient disposition or follow-up order when push notifications were employed: CXR to disposition, 80 minutes (interquartile range [IQR] 32-162 minutes) vs 56 minutes (IQR 18-141 minutes), difference 24 minutes (pl0.01); BMP to disposition, 128 minutes (IQR 62-225 minutes) vs 116 minutes (IQR 33-226 minutes), difference 12 minutes (pl0.01); UA to disposition, 105 minutes (IQR 43-200 minutes) vs 55 minutes (IQR 16-144 minutes), difference 50 minutes (pl0.01); RPP to disposition, 80 minutes (IQR 28-181 minutes) vs 37 minutes (IQR 10-116 minutes), difference 43 minutes (pl0.01); and D-dimer to CTPA, 14 minutes (IQR 6-30 minutes) vs 6 minutes (IQR 2.5-17.5 minutes), difference 8 minutes (pl0.01). The sixth scenario, Hb to blood transfusion (difference 19 minutes, p=0.73), did not meet statistical significance.Conclusion: Implementation of a push notification system for test result availability in the ED was associated with a decrease in lag time between test result and physician decision-making in the examined clinical scenarios. Push notifications were used in only a minority of ED patient encounters.
Effects of crack orientation and heat treatment on fatigue-crack-growth behavior of AM 17-4 PH stainless steel

Abstract The effects of heat treatment and crack orientation on fatigue-crack-growth (FCG) behavior of 17-4 precipitation hardening (PH) stainless steel (SS) fabricated via a laser powder bed fusion (LPBF) additive manufacturing (AM) system were investigated. Accurate representation of FCG thresholds, the region defining crack growth as either very slow or nonexistent, is extremely important in adoption of AM for structural applications. In this study, new methods called compression pre-cracking constant-amplitude (CPCA) and load-reduction (CPLR) were used to generate FCG rate data in the near-threshold (low-rate) regime using non-standard or modified compact specimens. For comparison, the current ASTM load-reduction (LR) method was also used. Results indicate that FCG behavior of AM 17-4 PH SS in the Paris regime was comparable to that of wrought 17-4 PH SS in the peak-age condition. Although the post-manufacturing heat treatment was found to be necessary in order to improve tensile strength of this alloy, the results of this study indicate that this particular heat treatment process had no influence on FCG behavior of LPBF 17-4 PH SS. The effect of crack orientation with respect to the build direction however was evident. FCG rates were slightly lower for specimens with a crack parallel to the build direction (i.e. longitudinal crack) in the Paris regime as compared to that of specimens with a perpendicular crack (i.e. transverse crack). The near-threshold FCG behavior for specimens with a longitudinal crack did not show the usual stress ratio (R)-shift from low to high R. The low-R data was vastly different than the data generated using the specimens with a transverse crack. Our results also imply that both the current ASTM standard LR method and the new CPLR method induce remote closure, which prematurely slows down crack growth and produces an abnormally high threshold.
A population of central complex neurons promoting orientation to airflow in Drosophila

How brain circuits convert sensory signals from diverse modalities into goal-oriented movements is a central question in neuroscience. In insects, a brain region known as the Central Complex (Cx) is believed to support navigation, but how this area organizes and processes diverse sensory cues is not clear. We recorded from genetically-identified Cx cell types in Drosophila and presented directional visual, olfactory, and airflow cues known to elicit orienting behavior. We found that a group of columnar neurons targeting the ventral fan-shaped body (ventral P-FNs) were consistently tuned for airflow direction. Silencing these neurons prevented flies from adopting stable orientations relative to airflow in closed-loop flight. Specifically, silenced flies selected improper corrective turns following changes in airflow direction, but not following airflow offset, suggesting a specific deficit in sensory-motor conversion. Our work provides insight into the organization and function of the insect navigation center.
Inexpensive and robust iron-based electrode substrates for water electrolysis and energy storage

Abstract The instability of iron under anodic conditions makes iron-based electrode substrates unsuitable for alkaline electrolyzers and rechargeable alkaline batteries. Therefore, significantly more expensive substrates such as nickel foam or sintered nickel are used. Nickel adds a significant cost to electrolysis and energy storage systems. We show that iron substrates can be stabilized using a unique protective thermal coating. These coatings can also yield some of the most electrocatalytically active electrodes in addition to showing no notable change in performance even after 1500 h of anodic polarization. Besides sintered iron, low-carbon steel mesh can be stabilized similarly. Low-carbon steel protected by a thin layer of lithium-doped cobalt spinel was found to be an excellent current collector for positive nickel hydroxide electrodes in alkaline batteries. Thus, surface-modified iron substrates, 40 times less expensive than nickel, are promising for lowering the material costs of alkaline water electrolyzers and rechargeable alkaline batteries.
Surgical Treatments of Epilepsy

Nearly 30% of epilepsy patients are refractory to medical therapy. Surgical management of epilepsy is an increasingly viable option for these patients. Although surgery has historically been used as a palliative option, improvements in technology and outcomes show its potential in certain subsets of patients. This article reviews the two main categories of surgical epilepsy treatment—resective surgery and neuromodulation. Resective surgery includes temporal lobe resections, extratemporal resections, laser interstitial thermal therapy, and disconnection procedures. We discuss the three main types of neuromodulation—vagal nerve stimulation, responsive neurostimulation, and deep brain stimulation for epilepsy. The history and indications are explored for each type of treatment. Given the myriad types of resection and neuromodulation techniques, patient selection is reviewed in detail, with a discussion on which patients are most likely to benefit from different treatment strategies. We also discuss outcomes with examples of the pertinent landmark trials and their results. Finally, complications and surgical technique are reviewed. As new indications emerge and patient selection is refined, surgical management will continue to evolve as an adjuvant therapy for epileptic patients.
The Metabolic Stability of the Nicotinic Acetylcholine Receptor at the Neuromuscular Junction

The clustering and maintenance of nicotinic acetylcholine receptors (AChRs) at high density in the postsynaptic membrane is a hallmark of the mammalian neuromuscular junction (NMJ). The regulation of receptor density/turnover rate at synapses is one of the main thrusts of neurobiology because it plays an important role in synaptic development and synaptic plasticity. The state-of-the-art imaging revealed that AChRs are highly dynamic despite the overall structural stability of the NMJ over the lifetime of the animal. This review highlights the work on the metabolic stability of AChRs at developing and mature NMJs and discusses the role of synaptic activity and the regulatory signaling pathways involved in the dynamics of AChRs.
SiC-Based 5-kV Universal Modular Soft-Switching Solid-State Transformer (M-S4T) for Medium-Voltage DC Microgrids and Distribution Grids

Medium-voltage dc (MVdc) grids are attractive for electric aircraft and ship power systems, battery energy storage system (BESS), fast charging electric vehicle (EV), etc. Such EV or BESS applications need isolated bidirectional MVdc to low-voltage dc (LVdc) or LVac converters. However, the existing Si-based solutions cannot fulfill the requirements of a high-efficiency and robust converter for MVdc grids. This article presents a 5-kV SiC-based universal modular solid-state transformer (SST). This universal current-source SST can interface either an LVac or LVdc grid with an MVdc grid in single-stage power conversion, while the conventional dual-active bridge (DAB) converter needs an additional inverter. The proposed SST module using 3.3-kV SiC MOSFET s and diodes is bidirectional and can serve as a building block in series or parallel for higher voltage higher power systems. The topology of each module is based on the soft-switching solid-state transformer (S4T) with reduced conduction loss, which features reduced electromagnetic interference electromagnetic interference (EMI) through controlled dv/dt, and high efficiency with full-range zero-voltage switching for main devices and zero-current switching for auxiliary devices. Operation principle of the modular S4T (M-S4T), capacitor voltage balancing control between the cascaded modules, design of components including a medium-voltage (MV) medium-frequency transformer (MFT) to realize a 50-kVA, 5-kV dc to 600 V dc or 480 V ac M-S4T are presented. Importantly, the MV MFT prototype achieves very low leakage inductance (0.13%) and 15-kV insulation with coaxial cables and nanocrystalline cores. The proposed universal modular SST is compared against the DAB solution and verified with dc–dc and dc–ac simulation and 4-kV experimental results. Significantly, the MV experimental results of a modular dc transformer with each module at MVdc are rarely covered in the literature and reported for the first time.
Redox-active rGO-nZVI nanohybrid-catalyzed chain shortening of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS)

Abstract Per- and polyfluoroalkyl substances (PFASs) are exceptionally stable chemicals due to their strong C F bonds. Nanoscale zero-valent iron (nZVI) particles have the potential to remove and degrade PFASs through redox activity. In this study, we deposited nZVI onto two-dimensional reduced graphene oxide (rGO) nanosheets and tested these synthesized rGO-nZVI nanohybrid (NH) for the treatment of a mixture of short- and long-chain PFASs in water with and without H2O2. All PFASs were removed at a higher efficiency by the rGO-nZVI NH than by the parent materials rGO and nZVI. Notably, the long-chain PFASs were removed at a faster rate than the short-chain PFASs. After a 10 min exposure to the rGO-nZVI NH without H2O2, the long-chain PFASs (perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)) were removed by 85 % and 39 %, respectively, while short-chain PFASs (perfluoropentane sulfonic acid and perfluoropentanoic acid) were removed by 19 % and 18 %, respectively. The addition of H2O2 enhanced the PFAS treatment performance by 10–18 %, which can be attributed to the generation of reactive oxygen species by the rGO-nZVI NH. Liquid chromatography high-resolution mass spectrometry analysis confirmed the formation of unique shorter chain and partially defluorinated PFAS-Fe complexes from both PFOS and PFOA.
Validation of Scores on the Lifestyle Practices and Health Consciousness Inventory With Black and Latinx Adults in the United States: A Three-Dimensional Model

The author tested the psychometric properties of the Lifestyle Practices and Health Consciousness Inventory (LPHCI), an interdisciplinary healthcare screening tool, with a stratified random sample ...
Knowing When to Say “When”

Knowing when to retire from a practice of medicine is perhaps one of the most vexing problems you as a physician will face during your career. For most physicians, your life has been devoted to caring for the sick, comforting the weary, relieving suffering, and promoting good health. Reaching that stage of your career where you see that there might be an end to your life’s work can be discouraging at best and overwhelmingly frightening at its worst. This chapter deals with some of the complexities of winding down a medical career, with an emphasis on surgery, providing some insight into thought processes and planning that can make the decision to retire manageable, and even exhilarating, when placed in the proper context.
Prospects for energy responsive urban planning and design

Publisher Summary This chapter discusses the prospects for energy responsive urban planning and design. Urban design expands the scale of individual buildings to the complexities of the physical design of groups of buildings and entire city blocks. Urban planning addresses the organization of cities, towns, and villages through several disciplines, such as political, economic, social, infrastructure systems, housing, work areas, recreation, etc. The scale increases progressively but not necessarily in complexity from individual buildings, to urban design, to urban planning, and finally global planning. To appreciate related energy problems, it is necessary to establish urban planning as the link between regional planning and urban design, and then establish urban design as the link between individual building design and urban planning. The chapter discusses the potentials for using renewable alternatives that radically changes development prospects and patterns. As all ambient energies received on earth are diffused, it stands to reason that the collection of these energies for human use should also be diffused. Consequentially, except for those cases when a high level of energy is needed, such as the operation of heavy machinery, human settlements would best optimize energy in low and medium density developments.
Some life lessons in the work place: Personal narrative/case study

Michael Schwartz, a lawyer deaf since birth, describes his journey as a professional for the last 32 years since his graduation from NYU School of Law in 1981. He offers a case study of his experiences with accommodations on the job as required by federal and state law. The study includes specific examples of what worked and what did not work for a deaf lawyer like him working at his craft. Schwartz wraps up with the lessons he learned over the last three decades as we moved from the model of non-compliance to that of compliance, even beyond compliance, with the mandates of law in the employment context.
When He Took Me Out With His People

If you can't hand him a book of aphorisms and trust him to pick out the best, What good can he possibly be to you when you're roommates-for-life?? I'll take as my model a microbe that only lives half a second. That's just Long enough to take one bite out of the universe and die... For today's one bite, Madrid offers this Hindu truth. He says Even this jagged hunk of quartz will one day flex its back and run up a tree. 77
Human Strategies for Multitasking, Search, and Control Improved via Real-Time Memory Aid for Gaze Location

OBJECTIVE: We aimed to elucidate how our domain-general cuing algorithm improved multitasking performance and changed behavioral strategies in human operators. BACKGROUND: Though many gaze-control systems have been designed, previous real-time gaze-aware assistance systems were not both successful and domain general. It is largely unknown what constitutes optimal search efficiency using the eyes, or ideal control using the mouse. It is unclear what the best coordinating strategies are between these two modalities. Our previously developed closed-loop multitasking aid drastically improved multitasking performance, though the behavioral mechanisms through which it acted were unknown. METHODS: We performed in-depth analyses and generated novel eye tracking and mouse movement measures, to explore the complex effects of our helpful system on gaze and motor behavior. RESULTS: Our overlay cuing algorithm improved control efficiency and reduced well-known biases in search patterns. This system also reduced micromanaging behavior, with humans rationally relying more on imperfect automation in experimental assistance cue conditions. We showed that mouse and gaze were more independently specialized in the helpful cuing condition than in control conditions. Specifically, with our aid, the gaze performed more global movement, and the mouse performed more local clustered movement. Further, the gaze shifted towards search over processing with the helpful cuing system. We also illustrated a relationship between the mouse and the gaze, such that in these studies, "the hand was quicker than the eye." CONCLUSIONS: Overall, results suggested that our cuing system improved performance and reduced short term working memory load on humans by delegating it to the computer in real time. Further, it reduced the number of required repeated decisions by an estimate of about one per second. It also enabled the gaze to specialize for improved visual search behavior, and the mouse to specialize for improved control.
Conceptual and Neurobiological Issues In Studies of Treatments Affecting Memory Storage

Publisher Summary This chapter reviews some of the conceptual issues involved in studies of retrograde amnesia and retrograde facilitation of memory, and summarizes recent findings having implications for the neurobiological bases of memory-storage processes. The findings of research in this area clearly indicate that retention is modified by treatments administered after training and the modulating influences are clearly time-dependent. Thus, the evidence provides strong support for the hypothesis that memory-storage processes are time-dependent. The results of studies of electrical stimulation of the brain demonstrate that some correlates, such as brain seizures, play no critical role in modulating storage. But such studies have not revealed the influences which are critical in affecting memory. The studies which use stimulation of specific brain regions suggest that brain stimulation can be an effective technique for investigating the role of specific neural systems in modulating memory-storage processes. Recent pharmacological studies have provided additional evidence that drugs can influence memory-storage processes. The major problem facing such studies is that of determining the neurobiological effect which underlies the observed behavioral effect.
Comparison of solution procedures to the facility location problem

Abstract This paper describes a mathematical model for determining optimum location for N facilities of the same size so as to maximize the sum of the material flow between the adjacent facilities. The model is based on a 0–1 integer program formulation of the problem which may produce an optimal, but infeasible solution, followed by a heuristic which begins with the 0–1 integer solution and generates a feasible solution. The procedure is capable of generating good solutions for medium-size problems. For location problems of size N = 4 to N = 16, the performance of the procedure in terms of the CPU time and the degree of closeness of the final solution to the optimal (yet infeasible) solution is measured and conclusions are drawn. The procedure is an addition to the existing pool of mathematical models for the facility layout problem.
Staging by Positron Emission Tomography Predicts Survival in Patients With Non-small Cell Lung Cancer

Background Positron emission tomography (PET) scanningis used increasingly to detect and stage lung cancer, but the testperformance characteristics and relationship of PET to patient outcomesremain undefined. Objective To determine the testperformance characteristics and relationship of PET scanning stage topatient outcomes relative to the 1997 International System for the, Staging of Lung Cancer. Design Survival analysisusing pathologic staging as the criterion standard for comparison ofsurvival as predicted by staging by PET and CT. Setting University-based hospital. Patients All consecutive patients undergoing PET scanningfor the evaluation of possible non-small cell lung cancer (NSCLC)during a 5-year period. Main outcome measures Long-term survival of patients with NSCLC after staging by PET. Results One hundred fifty-two thoracic PET scans wereobtained for the staging of possible NSCLC during a 5-year period. Onehundred twenty-three patients (81%) demonstrated increased 18 F-fluorodeoxyglucose uptake. The overall sensitivity andspecificity of PET for detecting malignancy were 95% and 67%,respectively, compared with 100% and 27% for chest CT. PET and CT hadsimilar accuracy for staging the overall extent of disease (91% and89%, respectively). PET stage correlated highly with survival usingeither nodal location or overall stage (p = 0.003, p = 0.002), asdid pathologic staging (p = 0.0001, p = 0.0001). CT scan resultsdid not accurately predict survival (p = 0.608, p = 0.338). Conclusion PET scanning is a highly sensitive technologicadvance in detecting and staging of thoracic malignancy and may moreaccurately predict the likelihood of long-term survival in patientswith NSCLC than chest CT does.
Colloidal Crystals Made of Polystyrene Spheroids: Fabrication and Structural/Optical Characterization

This paper describes the fabrication and characterization of colloidal crystals constructed from spheroidal building blocks with well-controlled major-to-minor ratios. Such a crystalline lattice was fabricated by infiltrating an opaline lattice of monodispersed polystyrene spheres with an elastomer precursor such as poly(dimethylsiloxane) (or PDMS), followed by thermal curing and stretching of the composite film at a temperature higher than the glass transition temperature of polystyrene. In this process, the polystyrene spheres were transformed into spheroids through viscoelastic deformation, while the long-range order of this three-dimensional lattice was essentially preserved. Because of the low contrast in the refractive index, the colloidal crystal fabricated in the present work exhibited a stop band (rather than a complete band gap) in the optical regime. The position of this stop band was determined by the diameter of the polystyrene spheres and the elongation ratio of the elastomeric composite. Wh...
Homogeneous layer models for high-spatial-frequency dielectric surface-relief gratings: conical diffraction and antireflection designs

The validity of various homogeneous layer models for high-spatial-frequency rectangular-groove (binary) dielectric surface-relief gratings is examined for both nonconical and conical diffraction. In each model the grating is described by a slab of uniaxial material with its optic axis parallel to the grating vector. The ordinary and principal extraordinary indices of the slab depend on the grating filling factor, the substrate and cover refractive indices, and the ratio of the wavelength to the grating period. These indices can be determined by solving two transcendental equations. Higher-order indices are defined as the exact solution to these equations. Second-order indices (second-order dependence on the wavelengthto- period ratio) and first-order indices (no dependence on the wavelength-to-period ratio) are defined by approximate solutions to these equations. Layer models using higher-order and second-order indices are shown to be accurate for high-spatial-frequency gratings, even at wavelength-to-period ratios near the onset of higher-order propagating diffracted waves. These models are used to design example antireflecting gratings on silicon substrates, including designs for conical incidence. All designs are evaluated and optimized by exact rigorous coupled-wave analysis.
No evidence of Epstein-Barr virus association with Merkel cell carcinoma

Background: Merkel cell carcinoma (MCC) is an aggressive tumor of cutaneous neuroendocrine cells with a reported 13-fold increased incidence in immunocompromised patients, raising the possibility that it is driven by an oncogenic virus. Additionally, Merkel cell hyperplasia is seen in the Epstein–Barr virus (EBV)-driven process oral hairy leukoplakia, and EBV is known to be involved in the pathogenesis of several other malignancies. Objective: We tested the hypothesis that EBV is involved in MCC. Methods: We employed EBV-encoded RNA in situ hybridization (ISH), lytic EBV ISH, latent membrane protein 1 immunohistochemistry, and BamH1Z leftward reading frame 1 immunohistochemistry to detect and localize EBV in paraffin sections of MCC from five patients as well as seven other cutaneous tumors and positive controls for EBV infection. Results: Positive controls reacted appropriately. However, there was no evidence of latent or lytic EBV in any of the MCC biopsies or other cutaneous tumors. Conclusion: Our findings suggest that EBV is not associated with MCC.
VISUAL ORIENTATION OF CERATITIS CAPITATA FLIES TO FRUIT MODELS

Wooden and rubber fruit models of different shapes, colors, and sizes were hung in fruiting coffee trees. Spheres (7.5 cm in diam) were much more attractive to Ceratitis capitata (Wiedemann) than cubes, cylinders, or rectangles of equivalent surface area. Black and yellow were the most attractive of eight colors, and white and grey were the least attractive. When an array of sphere sizes were tested, the attraction to flies increased as the size of yellow spheres increased from 1.5 to 18 cm diam. Trimedlure (tert-butyl 4(5)-chloro-2-methylcyclohexanecarboxylate) enhanced the attraction for males when added to 20.3 times 25.4-cm yellow rectangles and to 7.5-cm black spheres. ZUSAMMENFASSUNG VISUELLE ORIENTIERUNG ADULTER CERATITIS CAPITATA AUF FRUCHTATTRAPPEN Fruchtattrappen aus Holz und Kautschuk verschiedener Farbe und Grosse haben sich nach Prokopy (1968) als attraktiv auf R. pomonella (Walsh) in Apfelbaumen erwiesen. Aehnliche Resultate ergaben sich, als diese mit Stikem® uberzogenen Korper in Kaffeebaumen auf Kana, Hawaii aufgehangt wurden und C. capitata beider Geschlechter anzogen. Es wurde gezeigt, dass eine Kugel (7,5 cm Durchmesser) viel attraktiver ist als ein Zylinder, ein Rechteck oder ein Kubus gleicher Flache (Tafel I, Exper. 2). Gelbe Kugeln, die wahrscheinlich die Reflexion des Laubwerks nachahmen, wurden mit zunehmender Grosse fur beide Geschlechter attraktiver. Schwarze Kugeln, die wahrscheinlich die spektrale Absorption von Fruchten nachahmen, zeigten eine optimale Attraktion zwischen 3,2 und 7,5 cm Durchmesser. Gelbe und schwarze Kugeln von 7,5 cm Durchmesser waren gleich anziehend und waren am attraktivsten von acht berucksichtigten Farben, wahrend weiss und grau am wenigsten attraktiv waren. In einer zusatzlichen Studie wurde Trimedlure, ein Mannchenlockstoff, auf einen Wattebausch gebracht und an eine schwarze 7,5 cm Kugel und an ein gelbes 20 × 25 cm Rechteck gehangt. Damit wurde die Attraktion beider Korper fur Mannchen, nicht aber fur Weibchen erhoht. Die Verwendung eines Mannchen- oder Weibchenlockstoffs zusammen mit visuellen Fallen kann zur Entwicklung einer wirksameren Falle fuhren.
Minimal Extensions of Algebraic Groups and Linear Independence

Abstract We introduce the notion of a minimal extension of t -groups. Linear independence of the coordinates of the logarithm of an algebraic point in a minimal extension of t -groups follows naturally from linear independence of the coordinates of the image in the tangent space of the base t -group. We illustrate this principle through a leisurely parade of examples. In particular, we establish a general theorem about divided derivatives for t -modules. Minimal extensions turn out to correspond to Frattini covers for t -groups.
Proximate sulfhydryl groups in the acetylglutamate complex of rat carbamylphosphate synthetase I: Their reaction with the affinity reagent 5′-p-fluorosulfonylbenzoyladenosine

Abstract A preparation of rat carbamylphosphate synthetase I, isolated in the presence of antipain and stable without glycerol, has been used to investigate the effect of the allosteric activator, N -acetyl- l -glutamate (AcGlu), on the sulfhydryl chemistry of the enzyme. The enzyme · AcGlu complex was rapidly inactivated by several sulfhydryl group reagents and the ATP analog, 5′- p -fluorosulfonylbenzoyladenosine (FSO 2 BzAdo), with the loss of two sulfhydryl groups per monomer. Inactivation was much slower without AcGlu, and ATP/Mg 2+ /K + provided complete protection. Reaction with a 1.1 molar excess of 4,4′-dipyridyldisulfide resulted in an intramonomer disulfide bond between groups that are probably juxtaposed in the activated enzyme, because 1.1 equivalents of the vicinal dithiol reagent, phenylarsine oxide, eliminated the rapid reaction with the disulfide. Evidence is presented that the same disulfide bond was formed in the reactions with 5-thiocyano-2-nitrobenzoic acid and FSO 2 BzAdo. Inactivation by FSO 2 BzAdo was a pseudo-first-order reaction. The concentration dependence of the rate is consistent with the reaction proceeding through a noncovalent complex ( K I = 67 μm and k 2 = 0.23 min −1 at pH 7.0, 30 °C). Protection from FSO 2 BzAdo by ATP required Mg 2+ in excess of ATP with K MgATP = 4.5 μm at saturating free Mg 2+ (0.1 m K + ) and K Mg 2+ = 6.5 m. K MgATP is close to K d for the molecule of ATP that contributes the phosphoryl group of carbamylphosphate (H. B. Britton, V. Rubio, and S. Grisolia, (1979) Eur. J. Biochem. 102, 521–530]; K Mg 2+ agrees with the minimum value for the steady-state kinetic parameter, K i ,Mg 2+ , obtained under the same conditions. Dissociation constants for adenosine (320 μ m ), MgADP (110 μ m ) at 10 m m Mg 2+ , and AcGlu (100 μ m ) were also estimated.
Joint damping and nonlinearity in dynamics of space structures

Analysis of the effect of linear joint characteristics on the vibration of a free-free, three-joint beam model shows that increasing joint damping increases resonant frequencies and modal damping, but only to the point at which the joint gets «locked up» by damping. The maximum amount of passive modal damping obtainable from the joints is greater for low-stiffness joints and for modal vibrations where large numbers of joints are actively participating. A joint participation factor is defined to study this phenomenon. Analysis of the nonlinear three-joint model, with cubic spring at the joints, shows classical single-degree-of-freedom nonlinear response behavior at each resonance of the multiple-degree-of-freedom
A solid sample preparation method that reduces signal suppression effects in the MALDI analysis of peptides.

Here we report on the application of a solid−solid (SS) sample preparation protocol for the MALDI analysis of peptides and multicomponent peptide mixtures. Our results with a series of model peptides indicate that a SS MALDI sample preparation protocol is useful for the analysis of peptides in the 1−3 kDa mass range. MALDI mass spectra recorded for peptides in this size range using a SS sample preparation were of a quality comparable to spectra recorded using a conventional dried-droplet (DD) sample preparation. Our results with several model peptide mixtures indicate that one advantage of a SS sample preparation protocol for the MALDI analysis of peptides is that it can significantly reduce signal suppression effects in multicomponent mixtures. MALDI results obtained using a SS sample preparation protocol are also more reproducible than results obtained using a conventional DD sample preparation protocol.
Multiple Binding Modes between HNF4α and the LXXLL Motifs of PGC-1α Lead to Full Activation

Hepatocyte nuclear factor 4α (HNF4α) is a novel nuclear receptor that participates in a hierarchical network of transcription factors regulating the development and physiology of such vital organs as the liver, pancreas, and kidney. Among the various transcriptional coregulators with which HNF4α interacts, peroxisome proliferation-activated receptor γ (PPARγ) coactivator 1α (PGC-1α) represents a novel coactivator whose activation is unusually robust and whose binding mode appears to be distinct from that of canonical coactivators such as NCoA/SRC/p160 family members. To elucidate the potentially unique molecular mechanism of PGC-1α recruitment, we have determined the crystal structure of HNF4α in complex with a fragment of PGC-1α containing all three of its LXXLL motifs. Despite the presence of all three LXXLL motifs available for interactions, only one is bound at the canonical binding site, with no additional contacts observed between the two proteins. However, a close inspection of the electron density map indicates that the bound LXXLL motif is not a selected one but an averaged structure of more than one LXXLL motif. Further biochemical and functional studies show that the individual LXXLL motifs can bind but drive only minimal transactivation. Only when more than one LXXLL motif is involved can significant transcriptional activity be measured, and full activation requires all three LXXLL motifs. These findings led us to propose a model wherein each LXXLL motif has an additive effect, and the multiple binding modes by HNF4α toward the LXXLL motifs of PGC-1α could account for the apparent robust activation by providing a flexible mechanism for combinatorial recruitment of additional coactivators and mediators.
Component tradeoffs and technology breakpoints for a 50 Mbps to 3.2 Gbps fiber optic data bus for space applications

The design of the optical portion of a fiber optic data bus for space applications is described. A maximum NRZ data rate of 1.9 Gbps is predicted using low risk components which have either been demonstrated in space or for which sufficient qualification data are available. Substitution of lasers and fibers for higher bandwidth components are expected to extend the data rates to 4 Gbps but require additional qualification effort.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Marital Well-Being Over Time Among Black and White Americans: The First Seven Years

We examined patterns of marital well-being over the first 7 years of marriage and whether factors connected to early marital well-being during year 1 impacted marital well-being over time. Data were collected as part of a longitudinal panel study following 199 Black American and 174 White American during the first 7 years of marriage. Multilevel growth curve modeling revealed that race, income, and premarital child affected husbands’ marital well-being in year 1. Education, wives’ employment status, and divorced parents influenced wives’ marital well-being at year 1. After accounting for differences in these early marital conditions, having a child before marriage was significant in predicting the rates of change over time for husbands. Divorced parents affected the rate of change in marital well-being for wives. The findings suggest that as couples settle into their marriages, risk factors have fewer consequences on marital well-being.
An investigation into the relative influence of alkoxide and thiolate ligands on the metal–carbon triple bond in X3MCH compounds, where M=Cr, Mo and W and X=OH, SH, OCH3, SCH3, OCF3 and SCF3 from electronic structure calculations

Abstract Electronic structure calculations using density functional theory with the aid of the gaussian -98 package have been employed on the model Group 6 metal alkylidyne complexes X 3 MCH, where M=Cr, Mo and W and X=OH, SH, OCH 3 , SCH 3 , OCF 3 and SCF 3 . Collectively, these calculations reveal that the relative energies of the metal–carbon π-bonding molecular orbitals are greatly influenced by the metal and the ancillary ligand X. In comparing the bonding in related O and S containing molecules, the effect of oxygen is to increase the relative energy of the M–C π bond by approximately 1 eV as a result of M–O π antibonding interactions. In contrast, the ligand-based lone-pair orbitals lie higher in energy for sulfur and for the series where X=SH, SCH 3 and SCF 3 , the HOMO is a sulfur lone-pair combination of a 2 symmetry in the C 3 v point group. The relative influence of H, CH 3 and CF 3 within each series is as expected based on their electron releasing properties. A comparison is made with related compounds having metal to metal or metal to nitrogen triple bonds.
Research Findings as Testimony: A Note on the Ethnographer as Expert Witness

This paper recounts a number of difficulties encountered by the author (then a graduate student) in the course of giving "expert" testimony in a class-action lawsuit seeking recognition of the right to shelter for homeless men in New York. Chief among such difficulties was the presumptive classification of much ethnographic material as "hearsay." An obscure exception to the hearsay rule—"reputation"—is introduced, and its value as applied in the present case and as a device for introducing evidence obtained through interviews generally is discussed.
Preparation of single crystals of Pt group transition metals and alloys

Abstract A method of growing and annealing single-crystals of Pt group metals and alloys is described. The annealing process includes oxygen treatment which proved to be important in obtaining high residual resistance ratios. The final residual resistance ratios obtained were 2200 for rhodium crystals and 4600 for palladium crystals.
Supporting children’s mathematical understanding: professional development focused on out-of-school practices

This study describes the Reflection Connection Cycle professional development designed to support teachers’ use and appreciation of students’ out-of-school practices related to school mathematics. The year-long program incorporated group lesson design, readings, and video analysis for 14 elementary school (ages 5–12) teachers. Analysis of lesson development, written reflections, and analysis of teacher talk revealed important patterns related to the difficulty in writing lessons that built on students’ informal understandings. While initial lessons focused solely on the context of practices like gardening and sports, subsequent lessons show a greater concern for the mathematics in which children were engaged within a practice. A Multi-approach Engagement Framework is presented both as a tool to support further professional development efforts and as a means to describe stability and change in teachers’ efforts to connect in-school and out-of-school mathematical understandings.
Properties of Fluorescent Semiconductor Nanocrystals and their Application to Biological Labeling

We review recent advances in the development of colloidal fluorescent semiconductor nanocrystals (a class of quantum dots) for biological labeling. Although some of the photophysical properties of nanocrystals are not fully understood and are still actively investigated, researchers have begun developing bioconjugation schemes and applying such probes to biological assays. Nanocrystals possess several qualities that make them very attractive for fluorescent tagging: broad excitation spectrum, narrow emission spectrum, precise tunability of their emission peak, longer fluorescence lifetime than organic fluorophores and negligible photobleaching. On the down side, their emission is strongly intermittent ("blinking”) and their size is relatively large for many biological uses. We describe how to take advantage of nanocrystals’ spectral properties to increase the resolution of fluorescence microscopy measurements down to the nanometer level. We also show how their long fluorescence lifetime can be used to observe molecules and organelles in living cells without interference from background autofluorescence, a pre-requisite for single molecule detectability. Finally, their availability in multicolor species and their single molecule sensitivity open up interesting possibilities for genomics applications.
Real-time color-frame animation for visual psychophysics on the Macintosh computer

Psychophysical experiments involving moving stimuli require the rapid presentation of animated sequences of images. Although the Macintosh computer is widely used as a color graphics computer in research laboratories, its animation capabilities are generally ignored because of the speed limitations of drawing to the screen. New off-screen color graphics structures help to avoid the speed limitations so that real-time color or gray-scale visual motion stimuli may be generated. Precomputed animation frames are stored in off-screen memory and then rapidly transferred to the screen sequentially. The off-screen graphics structures may also be saved to disk in “Picture” form as “resources” for later retrieval and playback, allowing the experimenter to build in advance a collection of moving stimuli to use in future experiments. Code examples in the C programming language are provided, and the relative strengths and weaknesses of Macin-tosh color-frame animation for psychophysical experimentation are discussed.
Prediction of protein structure by emphasizing local side-chain/backbone interactions in ensembles of turn fragments.

The prediction strategy used in the CASP5 experiment was premised on the assumption that local side-chain/backbone interactions are the principal determinants of protein structure at low resolution. Our implementation of this assumption made extensive use of a scoring function based on the propensities of the 20 amino acids for 137 different sub-regions of the Ramachandran plot, allowing estimation of the quality of fit between a sequence segment and a known conformation. New folds were predicted in three steps: prediction of secondary structure, threading to isolate fragments of protein structures corresponding to one turn plus flanking helices/strands, and recombination of overlapping fragments. The most important step in this fragment ensemble approach, the isolation of turn fragments, employed 2 to 6 sequence homologues when available, with clustering of the best scoring fragments to recover the most common turn arrangement. Recombinants formed between 3 to 8 turn fragments, with cross-overs confined to helix/strand segments, were selected for compactness plus low energy as estimated by empirical amino acid pair potentials, and the most common overall topology identified by visual inspection. Because significant amounts of steric overlap were permitted during the recombination step, the final model was manually adjusted to reduce overlap and to enhance protein-like structural features. Even though only one or two models were submitted per target, for several targets the correct chain topology was predicted for fragment lengths up to 100 amino acids.
Eu2+ and V2+ as electrode kinetic probes of the structure of the diffuse layer in dilute electrolytes

Abstract The structure of the diffuse double layer at positive electrode charges in dilute perchlorate, chloride and bromide electrolytes is inferred from the kinetics of oxidation of the Eu2+ and V2+ cations. Diffuse layer potentials calculated from the measured kinetics disagree, both in magnitude and (in some cases) in sign with potentials calculated from electrocapillary data and Gouy-Chapman-Stern theory. The possible origin of the discrepancies and their consequences in attempts to apply Frumkin double layer corrections or to detect discreteness-of-charge effects are discussed.
Overestimation of Organic Phosphorus in Wetland Soils by Alkaline Extraction and Molybdate Colorimetry

Accurate information on the chemical nature of soil phosphorus is essential for understanding its bioavailability and fate in wetland ecosystems. Solution phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy was used to assess the conventional colorimetric procedure for phosphorus speciation in alkaline extracts of organic soils from the Florida Everglades. Molybdate colorimetry markedly overestimated organic phosphorus by between 30 and 54% compared to NMR spectroscopy. This was due in large part to the association of inorganic phosphate with organic matter, although the error was exacerbated in some samples by the presence of pyrophosphate, an inorganic polyphosphate that is not detected by colorimetry. The results have important implications for our understanding of phosphorus biogeochemistry in wetlands and suggest that alkaline extraction and solution 31P NMR spectroscopy is the only accurate method for quantifying organic phosphorus in wetland soils.
LIONS: An AWGR-Based Low-Latency Optical Switch for High-Performance Computing and Data Centers

This paper discusses the architecture of an arrayed waveguide grating router (AWGR)-based low-latency interconnect optical network switch called LIONS, and its different loopback buffering schemes. A proof of concept is demonstrated with a 4 × 4 experimental testbed. A simulator was developed to model the LIONS architecture and was validated by comparing experimentally obtained statistics such as average end-to-end latency with the results produced by the simulator. Considering the complexity and cost in implementing loopback buffers in LIONS, we propose an all-optical negative acknowledgement (AO-NACK) architecture in order to remove the need for loopback buffers. Simulation results for LIONS with AO-NACK architecture and distributed loopback buffer architecture are compared with the performance of the flattened butterfly electrical switching network.
Evaluating Programs That Save Lives: Discussion

"Discounting Human Lives," by Cropper, Portney, and Aydede, demonstrates that it is very difficult to elicit accurate preferences regarding life-saving activities. People's choices reflect both their preferences and their beliefs about how the world works. Thus, people may prefer to spend more on programs that save lives now rather than in the future not because they have low discount rates but because they believe that new lifesaving technology will be available in the future, or because they do not believe in the government's ability to keep its promises regarding the future.