cssi/SciSciGPT-SciSciNet huggingface dataset:
Tomosynthesis-Based Imaging of the Breast

As more and more evidence about the long-term benefits of mammography screening in terms of mortality reduction is becoming publicly available, the role of mammography in the overall schema of screening for the early detection of breast cancer becomes less controversial (1,2). Mammography, in general, and full-field digital mammography (FFDM), in particular (or some modification thereof), is likely to remain a primary screening tool for the foreseeable future despite the less than optimal sensitivity and specificity associated with this approach to imaging of the breast for this purpose (3,4). To date, it appears that most recommendations for improving screening programs with additional imaging expect the ‘‘new’’ modalities to supplement, rather than replace, mammography (5–7). Women with heterogeneously dense or very dense breast tissue (typically rated density BIRADS 3 or 4) are particularly difficult to diagnose correctly with mammography, because overlapping tissue structures may mask the abnormality in question (8,9). It seems that all new imaging modalities designed to improve early detection and diagnoses of breast cancer in recent years focused primarily on this group of women, and, in many ways, compete with each other as to the role these modalities may play in screening this group. To date, these adjunct technologies to two-dimensional FFDM imaging include structural imaging basedmodalities, such as ultrasound (with or without tissue elastography) (5), dynamic imaging– based modalities, such as contrast-enhanced magnetic resonance imaging (10), and tissue-related functional imaging (molecular imaging) such as positron emission mammography and other molecular imaging based approaches (11). Each approach has both diagnostic and workflow advantages and limitations. Over the years, we have learned that under a screening paradigm, operational efficiency in terms of workflow, professional resource utilization as well as participant management issues, such as the need for repeated injections, frequently constitute important factors in our willingness and/or ability to successfully implement a very large volume of additional procedures into screening practices for the early detection of breast cancer.
GEOGRAPHIC VARIATION OF LOWER EXTREMITY AMPUTATION IN PATIENTS WITH PERIPHERAL ARTERY DISEASE: RESULTS FROM U.S. MEDICARE 2000-2008

Lower extremity (LE) amputations represent a failure of treatment for patients with peripheral artery disease (PAD) yet little is known about the geographic variation in performance of LE amputation. Using data from the Centers for Medicare & Medicaid Services (CMS) from January 1, 2000 to December
Implantation of balloon-expandable stents for coarctation of the aorta: implantation data and short-term results.

We report the immediate results and the short-term follow-up in a group of selected patients with coarctation of the aorta who underwent endovascular stent implantation. Balloon-expandable stents were implanted in 6 patients (mean age 19.8 ± 5.1 years) with coarctation of the aorta (4 recurrent and 2 native) who underwent a total of 7 procedures (6 implantation and 1 further expansion). The systolic peak pressure gradient was decreased from 36.7 ± 16.9 to 13.3 ± 23.2 mm Hg (P < 0.005). There was a 66% increase in the mean coarctation diameter from 9.3 ± 1.7 to 15.6 ± 3.1 mm (P = 0.001) with the ratio of the coarctation to descending aorta diameter, measured at the level of the diaphragm, increasing from 0.49 ± 0.1 to 0.81 ± 0.2 (P < 0.005). The dilatation was successful in expanding the stent to an acceptable diameter in 5 of 6 patients. One patient underwent successful further expansion of a stent implanted 22 months previously. There were no immediate complications during balloon expansion and stent implantation. One patient suffered a femoral arterial bleed requiring surgical repair. There was one unrelated death. All patients were hypertensive (systolic blood pressure >140 mm Hg) prior to stent implantation. At mean follow-up of 8 months, 3 patients are normotensive. There was no recurrence of coarctation, aortic dissection, or aneurysm formation in the patients in whom stent implantation was successful. These findings indicate that balloon-expandable stent implantation for coarctation of the aorta in selected patients is a safe and effective alternative approach for relieving the obstruction with a low complication rate and no recoarctation at short-term follow-up. © 1996 Wiley-Liss, Inc.
Vanadocalixarenes on Silica: Requirements for Permanent Anchoring and Electronic Communication

Grafted V(V)−calixarene complexes that are 1,3-disubstituted at the lower rim have been synthesized using an extraordinarily mild procedure, using the V(III)−calixarene precursor p-But−calix[4]−(OMe)2(O)2V−Cl (1c), which is subsequently grafted onto silica and, afterward, oxidized to yield material 2c. The calixarene acts as a sterically bulky chelating ligand and enforces isolated pseudo-octahedral vanadium centers on silica, as ascertained by 51V NMR spectroscopy and analysis of the UV/vis spectrum of materials after calixarene removal via calcination. 13C CP/MAS NMR spectroscopy of 2c reveals lack of a downfield-shifted ipso carbon resonance, which is strongly indicative of a high d-orbital electron density for the V metal centers in 2c, a result that is expected on the basis of a proposed simple geometric model that is consistent with single-crystal X-ray crystallographic data of early transition metal metallocalixarenes. This result motivates future programming of grafted metal centers with chemical ...
Neocytolysis on Descent from Altitude: A Newly Recognized Mechanism for the Control of Red Cell Mass

BACKGROUND: Studies of space-flight anemia have uncovered a physiologic process, neocytolysis, by which young red blood cells are selectively hemolyzed, allowing rapid adaptation when red cell mass is excessive for a new environment. OBJECTIVES: 1) To confirm that neocytolysis occurs in another situation of acute plethora-when high-altitude dwellers with polycythemia descend to sea level; and 2) to clarify the role of erythropoietin suppression. DESIGN: Prospective observational and interventional study. SETTING: Cerro de Pasco (4380 m) and Lima (sea level), Peru. PARTICIPANTS: Nine volunteers with polycythemia. INTERVENTIONS: Volunteers were transported to sea level; three received low-dose erythropoietin. MEASUREMENTS: Changes in red cell mass, hematocrit, hemoglobin concentration, reticulocyte count, ferritin level, serum erythropoietin, and enrichment of administered(13)C in heme. RESULTS: In six participants, red cell mass decreased by 7% to 10% within a few days of descent; this decrease was mirrored by a rapid increase in serum ferritin level. Reticulocyte production did not decrease, a finding that establishes a hemolytic mechanism.(13)C changes in circulating heme were consistent with hemolysis of young cells. Erythropoietin was suppressed, and administration of exogenous erythropoietin prevented the changes in red cell mass, serum ferritin level, and(13)C-heme. CONCLUSIONS: Neocytolysis and the role of erythropoietin are confirmed in persons with polycythemia who descend from high altitude. This may have implications that extend beyond space and altitude medicine to renal disease and other situations of erythropoietin suppression, hemolysis, and polycythemia.
MHD theory of Earth's magnetosheath for an axisymmetric model

An analysis is made of the Earth's magnetosheath along the Sun-Earth line under conditions that the IMF (Interplanetary Magnetic Field) is nearly parallel or anti-parallel to the solar wind flow. MHD conservation equations in temporally-averaged steady-state form for the mass, momentum and energy density are combined with the magnetic divergence and induction equations, a hard conducting-sphere model for the magnetopause, and an adiabatic equation of state in the magnetosheath. The equations are integrated from the nose of the bow shock to the magnetopause and reduced to a set of nonlinear-coupled equations for the magnetosheath thickness and average magnetosheath parameters, which are then used to obtain a new equation for the thickness of the magnetosheath. This is the first analytical equation for the magnetosheath thickness that has been derived, and it exhibits an interesting functional dependence on Alfven and sonic Mach number MA and Ms,the angle θ0 between the bow shock normal and the IMF, the Chapman-Ferraro constant k0 at the magnetopause, the polytropic index γ, and the thermal conductivity Qr at the bow shock. The thickness is found to decrease for decreasing Ms, but increase with decreasing MA It exhibits the qualitative feature found in both gasdynamic and θ0 ≥ 45° MHD simulations of an approximate linear variation of the magnetosheath thickness with the density jump ratio X across the bow shock, but it also exhibits a unique negative slope and an offset that is a function both of MA and of K0.
Gender and Transnational Gossip

Transnational social networks powerfully shape Mexican migration and enable families to stretch internationally. In an atmosphere of such high dependence on social networks, it would be rare for families not to be affected by the opinions of others. This article analyzes this often-overlooked aspect of social networks, gossip. I analyze gossip stories prevalent for one type of migrant family, those in which parents and children live apart. Drawing on over 150 ethnographic interviews and observation with members of Mexican transnational families and their neighbors in multiple sites, I describe both parents’ and children’s experiences with transnational gossip. I show that in a transnational context, gossip is a highly gendered activity with different consequences for men and women. Although targeting both women and men, transnational gossip reinforces the expectations that mothers be family caregivers and fathers be family providers even when physical separation makes these activities difficult to accomplish.
Lipid adjustment in the analysis of environmental contaminants and human health risks

The literature on exposure to lipophilic agents such as polychlorinated biphenyls (PCBs) is conflicting, posing challenges for the interpretation of potential human health risks. Laboratory variation in quantifying PCBs may account for some of the conflicting study results. For example, for quantification purposes, blood is often used as a proxy for adipose tissue, which makes it necessary to model serum lipids when assessing health risks of PCBs. Using a simulation study, we evaluated four statistical models (unadjusted, standardized, adjusted, and two-stage) for the analysis of PCB exposure, serum lipids, and health outcome risk (breast cancer). We applied eight candidate true causal scenarios, depicted by directed acyclic graphs, to illustrate the ramifications of misspecification of underlying assumptions when interpreting results. Statistical models that deviated from underlying causal assumptions generated biased results. Lipid standardization, or the division of serum concentrations by serum lipids, was observed to be highly prone to bias. We conclude that investigators must consider biology, biologic medium (e.g., nonfasting blood samples), laboratory measurement, and other underlying modeling assumptions when devising a statistical plan for assessing health outcomes in relation to environmental exposures.
Polybutadiene cross-linked with various diols — effect on thermal stability

The relationship between cross-linking and thermal stability as related to polybutadiene is the focus of current research. Cross-linked polybutadienes have been prepared using various diols as the cross-linking agent. Cross-linked polymers have been characterized by gel content, swelling ratios, infrared spectroscopy, and thermal analysis. These polymers are not highly cross-linked, as seen by gel content and swelling ratios, and cross-linking does not have a large effect on the onset temperature of the degradation. Nonetheless, extensive formation of a non-volatile residue occurs.
Environmental, Social, and Management Drivers of Soil Nutrient Mass Balances in an Extensive Andean Cropping System

Sustainable nutrient cycling in agroecosystems combining grazing and crops has global ramifications for protecting these ecosystems and for the livelihoods they support. We sought to understand environmental, management, and social drivers of nutrient management and sustainability in Andean grazing/crop systems. We assessed the impact of farmer wealth, fields’ proximity to villages, topography, and rangeland net primary productivity (NPP) on mass balances for nitrogen (N), phosphorus (P), and potassium (K) of 43 fields. Wealthier farmers applied greater total amounts (kg) of manure nutrients. However, higher manure application rates (kg ha−1) were associated with field proximity and NPP rather than wealth. Manure P inputs in far fields (> 500-m distant) were half those in near fields. Harvest exports increased with manure inputs (P < 0.001) so that balances varied less than either of these flows. Erosion nutrient losses in steeper far fields matched crop exports, and yields declined with increasing field slope (P < 0.001), suggesting that erosion reduces productivity. Balances for P were slightly positive in near and far fields (+2.2 kg P ha−1 y−1, combined mean) when calculated without erosion, but zero in near fields and negative in far fields with erosion included (−6.1 kg P ha−1 y−1 in far fields). Near/far differences in both inputs and erosion thus drove P limitation. Crop K exports dominated K balances, which were negative even without accounting for erosion. Modeled intensification scenarios showed that remediating far field deficits would require P addition and erosion reduction. Management nested within environmental constraints (NPP, erosion) rather than socioeconomic status drives soil nutrient sustainability in these agroecosystems. Time-lags between management and long-term degradation are a principal sustainability challenge to farming in these montane grazing/crop agroecosystems.
Preliminary characterization of phenyloxidase activity in the salivary secretion of the parasite, Exeristes roborator.

Abstract Melanization of artificial media accompanied feeding by the parasite Exeristes roborator and was found to be due to phenyloxidase activity secreted by the developing larvae into the diet. The enzyme was localized in the salivary glands and its possible significance to the host-parasite relationship discussed.
Inference for functions of parameters in discrete distributions based on fiducial approach: Binomial and Poisson cases

In this article, we propose a simple method of constructing confidence intervals for a function of binomial success probabilities and for a function of Poisson means. The method involves finding an approximate fiducial quantity (FQ) for the parameters of interest. A FQ for a function of several parameters can be obtained by substitution. For the binomial case, the fiducial approach is illustrated for constructing confidence intervals for the relative risk and the ratio of odds. Fiducial inferential procedures are also provided for estimating functions of several Poisson parameters. In particular, fiducial inferential approach is illustrated for interval estimating the ratio of two Poisson means and for a weighted sum of several Poisson means. Simple approximations to the distributions of the FQs are also given for some problems. The merits of the procedures are evaluated by comparing them with those of existing asymptotic methods with respect to coverage probabilities, and in some cases, expected widths. Comparison studies indicate that the fiducial confidence intervals are very satisfactory, and they are comparable or better than some available asymptotic methods. The fiducial method is easy to use and is applicable to find confidence intervals for many commonly used summary indices. Some examples are used to illustrate and compare the results of fiducial approach with those of other available asymptotic methods.
Impact of a Home-Based Activity and Dietary Intervention in People With Slowly Progressive Neuromuscular Diseases

Abstract Kilmer DD, Wright NC, Aitkens S. Impact of a home-based activity and dietary intervention in people with slowly progressive neuromuscular diseases. Objective To determine whether a home-based activity and dietary intervention can increase activity level, reduce caloric intake, and impact positively components of metabolic syndrome in a disabled population. Design Testing occurred at 3 points during the 6-month intervention period (baseline, 3mo, 6mo) and at 6 months postintervention. Each test point included laboratory testing of anthropometric and metabolic variables and 3 days of home-based activity and dietary monitoring. A personally tailored activity and dietary prescription based on baseline testing was implemented during the 6-month intervention period. Setting Human performance laboratory of a university and each subject's home. Participants Twenty adult volunteer ambulatory subjects with several types of slowly progressive neuromuscular disease (NMD). Intervention Using a pedometer, subjects were instructed to increase number of steps by 25% over their baseline determined from home monitoring. An individualized dietary prescription was provided focusing on problematic issues identified from the baseline dietary profile. Main Outcome Measures Body composition, physical activity, dietary intake, energy expenditure, gait efficiency, metabolic variables, and quality of life. Results At the end of the protocol, mean step count increased approximately 27% above baseline ( P =.001) and caloric intake decreased over 300kcal/d ( P =.002). Body fat percentage significantly decreased (from 33.3%±1.5% to 32.6%±1.6%, P =.032). Gait efficiency did not change, and metabolic variables did not show statistically significant improvement, although 2 of the 5 subjects originally meeting the criteria for metabolic syndrome at baseline no longer met the criteria at the end of the intervention period. Six months after completing the protocol, caloric intake remained significantly reduced ( P =.02), but although mean step count remained elevated, it was not statistically significant. Conclusions Using a home-based protocol, people with NMD can increase activity and reduce caloric intake. Although this 6-month program showed positive changes, it was insufficient to affect risk factors associated with metabolic syndrome. It remains to be seen if a program longer than 6 months or a more rigorous program could lead to a reduction in the risk factors associated with metabolic syndrome.
Secondary hypertension due to a renin-producing teratoma

Twenty cases of extrarenal renin-secreting tumors have been reported, but this is the first case of a renin-producing teratoma. The patient was a 17-year-old African American girl who presented with hypertension and hypokalemia, and who was documented to have a plasma aldosterone-to-renin activity ratio consistent with secondary aldosteronism. Computed tomography demonstrated a pelvic tumor suspicious for a teratoma. With no other apparent etiology for the secondary aldosteronism, the teratoma was suspected to be an extrarenal renin-secreting tumor. This was confirmed after surgery by pathologic evaluation, and significantly reduced requirements for antihypertensive medication and potassium supplementation.
Creating a model of customer equity for chain restaurant brand formation

Abstract The purpose of this research was to create and test a model of customer equity for chain restaurant brand formation. It has long been acknowledged that managing and enhancing customer equity influences a company's shareholder value, which is a reflection of long-term financial performance. A review of the current literature revealed three key determinants of customer equity: (1) value equity, (2) brand equity, and (3) relationship equity. Six hypotheses were derived and, based on data analysis, all six were supported. Value, brand, and relationship management were all confirmed to be important factors in enhancing customer equity in the chain restaurant industry. Further, brand equity has the strongest impact on the development of customer equity in this particular industry. Relationships among value equity, brand equity, and relationship equity were also identified. Managerial implications are discussed.
Severely comminuted distal radial fracture as an unsolved problem: Complications associated with external fixation and pins and plaster techniques

Seventy-six patients with severely comminuted distal radial fractures were treated at two institutions, of which the overwhelming majority were Frykman class VIII. Fifteen fractures were open. Thirty patients were seen at the University Hospital; 17 had pins and plaster and 13 had external fixation. Forty-six patients were seen at Kaiser Hospital; all had pins and plaster treatment. The complication rate for those with pins and plaster at the University Hospital was 53%; the complication for external fixation rate was 62%. The affiliated-hospital complication rate was 52%. All patients with ipsilateral forearm shaft and carpal fractures developed a nonunion of the carpal fracture. Few patients maintained anatomic reduction, and many had significant intra-articular malalignment. External fixation with threaded half pins did not obviate pin problems in our series. These methods may help manage severely comminuted distal radial fractures, but complications should be anticipated and alternative treatment considered, especially when ipsilateral carpal or forearm shaft fractures are present.
The brain's master circadian clock: Implications and opportunities for therapy of sleep disorders

The suprachiasmatic nuclei (SCN) residing in the anterior hypothalamus maintains a near-24-h rhythm of electrical activity, even in the absence of environmental cues. This circadian rhythm is generated by intrinsic molecular mechanisms in the neurons of the SCN; however, the circadian clock is modulated by a wide variety of influences, including glutamate and pituitary adenylate cyclase-activating peptide (PACAP) from the retinohypothalamic tract, melatonin from the pineal gland, and neuropeptide Y from the intergeniculate leaflet. By virtue of these and other inputs, the SCN responds to environmental cues such as light, social and physical activities. In turn, the SCN controls or influences a wide variety of physiologic and behavioral functions, including attention, endocrine cycles, body temperature, melatonin secretion, and the sleep-wake cycle. Regulation of the sleep-wake cycle by the SCN has important implications for development of therapies for sleep disorders, including those involving desynchronization of circadian rhythms and insomnia.
Why Do State Give Up Sovereignity

The Nordic States and European Unity, Christine Ingebritsen (Ithaca, N.Y.: Cornell University Press, 1998). 219 pp., cloth (ISBN: 0-801403484-X), $35.00. The Currency of Ideas: Monetary Politics in the European Union, Kathleen R. McNamara (Ithaca, N.Y.: Cornell University Press, 1998). 185 pp., cloth (ISBN: 0-8014-3432-7), $39.95; paper (ISBN: 0-8014-8602-5), $16.95. Books reviewed: The Nordic States and European Unity , Christine Ingebritsen The Currency of Ideas: Monetary Politics in the European Union , Kathleen R. McNamara
Differential effect of chronic morphine on mRNA encoding adenylyl cyclase isoforms: relevance to physiological sequela of tolerance/dependence

Abstract In opiate naive longitudinal muscle myenteric plexus tissue, facilitation (GS-mediated) and inhibition (Gi-mediated) of adenylyl cyclase (AC) activity is observed in response to low (nM) and high (μM) concentrations of sufentanil, respectively. Following chronic in vivo exposure to morphine, previously inhibitory concentrations produce excitatory effects. The present study was undertaken to explore the potential relevance of AC isoform-specific regulation to the qualitative change in opioid responsiveness following chronic morphine. Following persistent activation of opiate receptors, levels of AC I mRNA remain unchanged but that of AC IV is significantly augmented (approximately 37%; P
Ground test facility for SEI nuclear rocket engines

Nuclear Thermal Propulsion (NTP) has been identified as a critical technology in support of the NASA Space Exploration Initiative (SEI). In order to safely develop a reliable, reusable, long-lived flight engine, facilities are required that will support ground tests to qualify the nuclear rocket engine design. Initial nuclear fuel element testing will need to be performed in a facility that supports a realistic thermal and neutronic environment in which the fuel elements will operate at a fraction of the power of a flight weight reactor/engine. Ground testing of nuclear rocket engines is not new. New restrictions mandated by the National Environmental Protection Act of 1970, however, now require major changes to be made in the manner in which reactor engines are now tested. These new restrictions now preclude the types of nuclear rocket engine tests that were performed in the past from being done today. A major attribute of a safely operating ground test facility is its ability to prevent fission products from being released in appreciable amounts to the environment. Details of the intricacies and complications involved with the design of a fuel element ground test facility are presented in this report with a strong emphasis on safety and more » economy. « less
The acidity and proton affinity of the damaged base 1,N6-ethenoadenine in the gas phase versus in solution: intrinsic reactivity and biological implications.

1,N6-Ethenoadenine (ϵA) is a highly mutagenic lesion that is excised from human DNA by the enzyme alkyladenine DNA glycosylase (AAG). In an effort to understand the intrinsic properties of 1,N6-ethenoadenine, we examined its gas phase acidity and proton affinity using quantum mechanical calculations and mass spectrometric experimental methods. We measure two acidities for ϵA: a more acidic site (ΔHacid = 332 kcal mol−1; ΔGacid = 325 kcal mol−1) and a less acidic site (ΔHacid = 367 kcal mol−1; ΔGacid = 360 kcal mol−1). We also find that the proton affinity of the most basic site of 1,N6-ethenoadenine is 232−233 kcal mol−1 (GB = 224 kcal mol−1). These measurements, when compared to calculations, establish that, under our experimental conditions, we have only the canonical tautomer of 1,N6-ethenoadenine present. We also compare the gas phase acidic properties of ϵA with that of the normal bases adenine and guanine and find that ϵA is the most acidic. This supports the theory that AAG and other related enzyme...
Hyperreal transients in transfinite RLC networks

All prior analyses of transfinite electrical networks, as in Chapters 5 and 6 and in [50], [51], [54], have been restricted to purely resistive networks. That is, the branch parameters have only been (linear or nonlinear) resistors along with voltage and current sources. However, the technique employed in Chapter 6, whereby the transfinite network Nv is viewed as the end result of a sequence of finite networks that fill out Nv, now makes it possible to analyze transfinite electrical networks whose branch parameters are also allowed to be inductors and capacitors. This is certainly so if the resistors, inductors, and capacitors are linear and positive. By an RLC network we will mean an electrical network whose parameters are so restricted.
Use of conditional rule structure to automate clinical decision support: A comparison of artificial intelligence and deterministic programming techniques

A rule-based computer system was developed to perform clinical decision-making support within a medical information system, oncology practice, and clinical research. This rule-based system, which has been programmed using deterministic rules, possesses features of generalizability, modularity of structure, convenience in rule acquisition, explanability, and utility for patient care and teaching, features which have been identified as advantages of artificial intelligence (AI) rule-based systems. Formal rules are primarily represented as conditional statements; common conditions and actions are stored in system dictionaries so that they can be recalled at any time to form new decision rules. Important similarities and differences exist in the structure of this system and clinical computer systems utilizing artificial intelligence (AI) production rule techniques. The non-AI rule-based system possesses advantages in cost and ease of implementation. The degree to which significant medical decision problems can be solved by this technique remains uncertain as does whether the more complex AI methodologies will be required.
Maximum-Sized Matroids with No Minors Isomorphic to U 2,5 , F 7 , F − 7 or P 7

Let M be the class of simple matroids which do not contain the 5-point line U2,5, the Fano plane F7, the non-Fano plane F−7, or the matroid P7 as minors. Let h(n) be the maximum number of points in a rank-n matroid in M. We show that h(2) = 4, h(3) = 7, and h(n) = (n+12) for n ≥ 4, and we also find all the maximum-sized matroids for each rank.
Atomic layer deposition of Al2O3 on H-passivated Si: Al(CH3)2OH surface reactions with H/Si(100)-2×1

Infrared absorption studies of $\mathrm{Al}({\mathrm{CH}}_{3}{)}_{3}$ interacting with H-terminated Si reveal that O incorporation from gas-phase impurities may be a crucial factor in interface formation in atomic layer deposition. Hybrid density-functional calculations have therefore been carried out on silicon cluster models to investigate the possible pathways for reaction between the important atomic layer deposition side-reaction product $\mathrm{Al}({\mathrm{CH}}_{3}{)}_{2}\mathrm{OH}$ (DMAOH) and the $\mathrm{H}/\mathrm{S}\mathrm{i}(100)\ensuremath{-}2\ifmmode\times\else\texttimes\fi{}1$ surface. Comparisons with the analogous surface reactions for $\mathrm{Al}({\mathrm{CH}}_{3}{)}_{3}$ and ${\mathrm{H}}_{2}\mathrm{O}$ are made. In general, the DMAOH surface reaction pathways are characterized by an activation of reactions involving the OH groups and suppression of ${\mathrm{CH}}_{3}$ group reactions, compared to $\mathrm{Al}({\mathrm{CH}}_{3}{)}_{3}$ and ${\mathrm{H}}_{2}\mathrm{O}.$ A unique reaction pathway for DMAOH and the $\mathrm{H}/\mathrm{S}\mathrm{i}(100)\ensuremath{-}2\ifmmode\times\else\texttimes\fi{}1$ surface is identified resulting in the deposition of $\ensuremath{-}\mathrm{O}\ensuremath{-}\mathrm{A}\mathrm{l}({\mathrm{CH}}_{3}{)}_{2}$ on the surface, which is significant since it represents an atomic-layer interface between Si and ${\mathrm{Al}}_{2}{\mathrm{O}}_{3}.$ This reaction has an energy barrier of 1.3 eV and is the most thermodynamically favored pathway with an exothermicity of 0.9 eV.
Accurate estimation of the density of states from Monte Carlo transition probability data

This study develops an efficient approach for calculating the density of states from energy transition probability matrices generated from extended sampling Monte Carlo simulations. Direct and iterative variants of the method are shown to achieve high accuracy when applied to the two-dimensional Ising model for which the density of states function can be determined exactly. They are also used to calculate the density of states of lattice protein and Lennard-Jones models which generate more complex nonzero matrix structures. Whereas the protein simulations test the method on a system exhibiting a rugged free energy landscape, the Lennard-Jones calculations highlight implementation details that arise in applications to continuous energy systems. Density of states results for these two systems agree with estimates from multiple histogram reweighting, demonstrating that the new method provides an alternative approach for computing the thermodynamic properties of complex systems.
Near-field fiber optic chemical sensors and biological applications

Near-field optics has been applied in the nanofabrication of subwavelength optical fiber chemical and biological sensors and their operation in chemical and biological analysis. A thousandfold miniaturization of immobilized optical fiber sensors has been achieved by a near- field photo-nanofabrication technique, which is based on nanofabricated optical fiber tips and near-field photopolymerization. This technique has been further developed by multistep near- field nanofabrication and multidye probe fabrication. Multistep nanofabrication can further miniaturize optical fiber sensors, while multidye fabrication results in multifunctional optic and excitonic probes with extremely small size. These probes emit multiwavelength photons or produce excitons of different energy levels, and may have multiple chemical or biological sensitivities. The nondestructive submicrometer sensor has demonstrated its ability to carry out static and dynamic determinations of pH in intact rat conceptuses of varying gestational ages. The ability of the sensors to measure pH changes, in real time, in the intact rat conceptus, demonstrates their potential applications for dynamic analysis in multicellular organisms and single cells. The near-field interaction of photons with matter is discussed.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Improved microelectronics manufacturing using new laser technologies

The use of the 1.3 line and third harmonic of the diode pumped Nd:YAG laser provides a variety of new methods to address the continued advance towards smaller, lighter more complex microelectronics.
Transmembrane glycoprotein gp150 is a substrate for receptor tyrosine phosphatase DPTP10D in Drosophila cells

We have begun to explore the downstream signaling pathways of receptor protein tyrosine phosphatases (RPTPs) that control axon guidance decisions in the Drosophila central nervous system. We have focused our studies on the adhesion molecule-like gp150 protein, which binds directly to and is an in vitro substrate for the RPTP DPTP10D. Here we show that gp150 and DPTP10D form stable complexes in Drosophila Schneider 2 (S2) cells and in wild-type larval tissue. We also demonstrate that the DPTP10D cytoplasmic domain is sufficient to confer binding to gp150. gp150 has a short cytoplasmic domain containing four tyrosines, all found within sequences similar to immunoreceptor family tyrosine-based activation motifs (ITAMs). We demonstrate that gp150 is tyrosine phosphorylated in wild-type larvae. In S2 cells, gp150 becomes tyrosine phosphorylated following incubation with PTP inhibitors or upon coexpression of the Dsrc tyrosine kinase. Phosphorylated Dsrc and an unknown 40-kDa phosphoprotein form stable complexes with gp150, thereby implicating them in a putative gp150 signaling pathway. When coexpressed with gp150, either full-length DPTP10D or its cytoplasmic domain mediates gp150 dephosphorylation whereas a catalytically inactive DPTP10D cytoplasmic domain does not. The neural RPTP DPTP99A can also induce gp150 dephosphorylation but does not coimmunoprecipitate with gp150. Taken together, the results suggest that gp150 transduces signals via phosphorylation of its ITAM-like elements. Phosphotyrosines on gp150 might function as binding sites for downstream signaling molecules, thereby initiating a signaling cascade that could be modulated in vivo by RPTPs such as DPTP10D.
Switch‐reference in Papuan languages: A syntactic or Extrasyntactic device?

(1988). Switch‐reference in Papuan languages: A syntactic or Extrasyntactic device? Australian Journal of Linguistics: Vol. 8, No. 1, pp. 75-117.
Capacity of the isotropic fading multiple antenna downlink with magnitude feedback

We determine the capacity region of a single-cell isotropic fading multiple antenna downlink with perfect channel knowledge at the mobiles and only the knowledge of the magnitudes of the users' channel vectors at the base station. Using a scalar upperbound, we are able to prove the optimality of Gaussian codebooks on this vector broadcast channel. Numerical results are provided to compare magnitude feedback against opportunistic beamforming and antenna selection.
The Relationship between Tropical Easterly Waves and Surges over the Gulf of California during the North American Monsoon

Abstract Coastally trapped disturbances, which occur over the Gulf of California and are commonly referred to as gulf surges, are an important mechanism in the transport of low-level moisture into the southwestern United States. To determine whether or not gulf surges develop in association with the passage of tropical easterly waves, as hypothesized in previous studies, standard surface observations and European Centre for Medium-Range Weather Forecasts reanalysis data during the months of July and August over a 14-yr period are examined. Results indicate that tropical easterly wave troughs often cross western Mexico 1–3 days prior to surge onset at Yuma, Arizona, indicating a strong correlation between these two events. This analysis documents yet another mechanism by which the Tropics influences convection in the midlatitudes.
ion-implanted junctions and conducting layers in SiC

Abstract n-type conducting layers have been formed in n- and p-type hexagonal SiC and n-type cubic SiC by implanting ions from column V of the periodic table; N, P, Sb, or Bi. The implantations were made at room temperature and with energies ranging from 5 to 300 keV. The implanted layers have been evaluated by van der Pauw-Hall effect and sheet resistivity measurements and by scanning electron microscopy for anneal temperatures ranging from 1100 to 1800°C. Type conversion of the implanted layers to n-type has been observed after a 750°C anneal. Considerable lattice reordering is suggested from the observed carrier mobility values after annealing at 1600°C. We have attempted to form p-type layers in n-type SiC by implanting Re, B, Al, Ga, and Tl. Application of anneal procedures identical to those used to form n-type layers have not resulted in measurable p-type layers. The p-n junctions formed by the donor-implanted layers have been evaluated as a function of anneal temperature. After annealing at 1200°C...
SiC Whisker/Si3N4 Composites by a Chemical Mixing Process

A chemical mixing process has been developed for making SiC whisker/Si3N4 composites. The process involves in situ synthesis of SiC whiskers in Si3N4 powder by partial carbothermal reduction of silicon nitride in an argon atmosphere. The effects of reaction conditions and starting raw materials on the formation of SiC whiskers were studied. It has been demonstrated that the morphologies of the in situ synthesized whiskers can be modified by varying carbon-source materials and reaction conditions, and the amount of SiC formed in the product can be adjusted by changing the starting Si3N4-to-C ratio. The chemically mixed composite materials were densified by hot pressing with Y2O3 and Al2O3 as sintering aids. 12 refs.
Embedded slanted grating for vertical coupling between fibers and silicon-on-insulator planar waveguides

We propose a compact and efficient grating coupler for vertical coupling between optical fibers and planar waveguides. A grating with a parallelogram shape is designed to be etched through the entire high-index waveguide core. The coupler is optimized using a microgenetic algorithm coupled with a two-dimensional finite-difference time-domain method. Simulations show that up to 75.8% coupling efficiency can be obtained between a single-mode fiber and a 240-nm-thick silicon-on-insulator planar waveguide.
Low5 Boolean Subalgebras and Computable Copies

It is known that the spectrum of a Boolean algebra cannot contain a low4 degree unless it also contains the degree 0; it remains open whether the same holds for low5 degrees. We address the question differently, by considering Boolean subalgebras of the computable atomless Boolean algebra . For such subalgebras , we show that it is possible for the spectrum of the unary relation on to contain a low5 degree without containing 0.
FLIGHT RESPIRATION AND ENERGETICS

We use a comparative approach to examine some of the physiological traits that make flight possible. Comparisons of related fliers and runners suggest that fliers generally have higher aerobic metabolic capacities than runners but that the difference is highly dependent on the taxa studied. The high metabolic rates of fliers relative to runners, especially in insects, are correlated with high locomotory muscle cycle frequencies and low efficiencies of conversion of metabolic power to mechanical power. We examine some factors that produce variation in flight respiration and energetics. Air temperature strongly affects the flight metabolic rate of some insects and birds. Flight speed interacts with flier mass, so that small fliers tend to exhibit a J-shaped power curve and larger fliers a U-shaped power curve. As body size increases, mass-specific aerobic flight metabolism decreases in most studies, but mass-specific power output is constant or increases, leading to an increase in efficiency with size. Intraspecific studies have revealed specific genetically based effects on flight metabolism and power output and multiple ecological correlates of flight capabilities.
Origin of Florida Canyon and the role of spring sapping on the formation of submarine box canyons

Florida Canyon, one of a series of major submarine canyons on the southwestern edge of the Florida Platform, was surveyed using GLORIA, SeaBeam, and Deep-Tow technologies, and it was directly observed during three DSRV Alvin dives. Florida Canyon exhibits two distinct morphologies: a broad V-shaped upper canyon and a deeply entrenched, flat-floored, U-shaped lower canyon. The flat- floored lower canyon extends 20 km into the Florida Platform from the abyssal Gulf. The lower canyon ends abruptly at an ∼3 km in diameter semicircular headwall that rises 750 m with a >60° slope angle to the foot of the upper canyon. The sides of the lower canyon are less steep than its headwall and are characterized by straight faces that occur along preferred orientations and indicate a strong joint control. The upper canyon is characterized by a gently sloping, straight V-shaped central valley cut into a broad terrace. The flat floor of the upper canyon continues as terraces along the upper walls of the lower canyon. On the flanks of the upper canyon, there are five >50-m-deep, >0.5-km-wide, closed sink-hole-like depressions which indicate subsurface dissolution within the platform. The origin of the lower canyon is difficult to explain with traditional models of submarine canyon formation by external physical processes. The movement of ground water, probably with high salinities and reduced compounds along regional joints, may have focused the corrosive force of submarine spring sapping at the head of the lower canyon to produce the canyon9s present shape.
Comparisons of quad trees and 4-D trees: new results (VLSI layout)

A comparison is made between two tree data structures that support region queries for VLSI layout systems. In a previous study, J.B. Rosenberg (ibid., vol.CAD-4, no.1, p.53-67, 1985) demonstrated that four-dimensional trees have a faster speed but use more memory space than quad trees with bisector lists. In this study the authors show that quad trees without bisector lists, for some small threshold values, have a better speed and require less storage than four-dimensional trees. >
Recent insights into the role of NF-kappaB in ovarian carcinogenesis

The NF-κBs are a family of ubiquitously expressed transcription factors that have been described to be responsible for the establishment of an inflammatory response. Studies in the past decade have also demonstrated this family's role in the initiation and progression of hematological and solid tumors. Recently, research has uncovered a specific role for NF-κBs in the development and maintenance of ovarian cancer.
Solid‐Phase Acid Extraction Improves Thiobarbituric Acid Method to Determine Lipid Oxidation

Samples (110g) of raw (17.2-22.6% fat) and cooked 12.6-16.4% fat) ground beef in plastic cups were stored aerobically at 4±1 o C. Lipid oxidation was measured by four versions of the thiobarbituric acid (TBA) test, including aqueous acid extraction-C 18 (TBA-C 18 ), direct heating, distillation, and unmodified aqueous acid extraction; and by sensory evaluation of rancid odor after 0, 2, 4, 6, and 8 days storage. The TBA-C 18 method was more specific (P<0.05) and its limit of detcrmination was 20 times lower than the other methods in detecting malonaldehyde. Results correlated (r=0.856 to 0.883 in raw, and r=0.936 to 0.981 in cooked meat) with sensory evaluation scores
Mandated Choice: The Preferred Solution to the Organ Shortage?

Background.— A critical shortage of organs is perhaps the major barrier facing transplantation today. Adopting a system of presumed consent or mandated choice are among the solutions proposed. Under presumed consent, organs may be removed after death without explicit consent, unless the deceased had previously objected or the family objects at the time of death. Under mandated choice, all adults would be required to decide for themselves whether they wish to donate on their deaths and their decisions would be controlling. Methods.— To see if educated young people would support these proposals, I carried out two surveys at the University of Maryland, College Park, Md, of a total of 418 students who were at least 18 years of age. Result.— An overwhelming 90% would support mandated choice while a smaller percentage, just over 60%, would support presumed consent. The vast majority believe that the family should not be able to override the previously expressed wishes of their recently deceased loved one. Unfortunately, only a minority of respondents had discussed organ donation with their families and even fewer had signed donor cards. Conclusions.— Even young, educated people frequently fail to consider organ donation prospectively and this is a major barrier to organ retrieval. While presumed consent and mandated choice are designed to deal with this serious problem, mandated choice seems preferable and would likely receive widespread support. Therefore, I suggest that a small scale trial of mandated choice be undertaken as soon as possible in the hope of finding an acceptable system that will quickly and efficiently increase the supply of desperately needed organs. (Arch Intern Med.1992;152:2421-2424)
Screening for Psychosocial Dysfunction in Pediatric Inpatients

Screening pediatric inpatients for psychosocial dysfunction offers physicians an opportunity to identify emotional and behavioral problems that might otherwise go unrecognized. In this study, the Pediatric Symptom Checklist (PSC), a brief, parent-completed questionnaire, which has been validated in a variety of outpatient settings, was used to screen 98 pediatric inpatients. Results indicated that the PSC can be easily administered in a busy inpatient setting and is well-tolerated by both house staff and patients' parents as a routine part of the admissions process. The percentage of children who screened positive with the PSC in this inpatient setting was similar to the percentages generated by using the PSC in outpatient settings. Routine use of the PSC in inpatient settings serves to heighten house staff awareness of psychosocial concerns and facilitate parent-physician discussion of pediatric mental health issues.
Primary Malignant Melanoma of the Common Bile Duct

Abstract Primary malignant melanoma of the common bile duct is rare. To our knowledge, only 6 cases have been reported previously. The pathologic diagnosis of primary malignant melanoma in extracutaneous sites often requires the use of confirmatory immunohistochemical stains and electron microscopy studies, as well as tests to rule out other possible remote or concurrent primary sites. The presence of junctional activity adjacent to the tumor is another important requisite for the diagnosis of this entity. Nevertheless, absolute exclusion of a metastatic melanoma from an unknown occult site or regressed site is not entirely possible. We describe our observations in a case of primary malignant melanoma of the common bile duct in a 48-year-old man and discuss the criteria for diagnosis of primary melanoma.