cssi/SciSciGPT-SciSciNet huggingface dataset:
Quantitative 13C NMR of whole and fractionated Iowa Mollisols for assessment of organic matter composition.

Both the concentrations and the stocks of soil organic carbon vary across the landscape. Do the amounts of recalcitrant components of soil organic matter (SOM) vary with landscape position? To address this question, we studied four Mollisols in central Iowa, two developed in till and two developed in loess. Two of the soils were well drained and two were poorly drained. We collected surface-horizon samples and studied organic matter in the particulate organic matter (POM) fraction, the clay fractions, and the whole, unfractionated samples. We treated the soil samples with 5 M HF at ambient temperature or at 60 °C for 30 min to concentrate the SOM. To assess the composition of the SOM, we used solid-state nuclear magnetic resonance (NMR) spectroscopy, in particular, quantitative 13C DP/MAS (direct-polarization/magic-angle spinning), with and without recoupled dipolar dephasing. Spin counting by correlation of the integral NMR intensity with the C concentration by elemental analysis showed that NMR was ⩾85% quantitative for the majority of the samples studied. For untreated whole-soil samples with <2.5 wt.% C, which is considerably less than in most previous quantitative NMR analyses of SOM, useful spectra that reflected ⩾65% of all C were obtained. The NMR analyses allowed us to conclude (1) that the HF treatment (with or without heat) had low impact on the organic C composition in the samples, except for protonating carboxylate anions to carboxylic acids, (2) that most organic C was observable by NMR even in untreated soil materials, (3) that esters were likely to compose only a minor fraction of SOM in these Mollisols, and (4) that the aromatic components of SOM were enriched to ∼53% in the poorly drained soils, compared with ∼48% in the well drained soils; in plant tissue and particulate organic matter (POM) the aromaticities were ∼18% and ∼32%, respectively. Nonpolar, nonprotonated aromatic C, interpreted as a proxy for charcoal C, dominated the aromatic C in all soil samples, composing 69–78% of aromatic C and 27–36% of total organic C in the whole-soil and clay-fraction samples.
Analyzing engineering surface texture using wavelet filter

Analysis of surface profile generally involves filtering to separate short wavelengths from medium and long wavelengths. This is usually accomplished using digital filters. The wavelet filter is an ideal means to separate the profile into different bands. The space frequency localization and multiscale presentation of different wavelength components is useful in manufacturing process control and in establishing relationship between surface texture and function. The use of wavelet filter to analyze surface is explored in this paper. This paper deals with the evaluation of suitable wavelet basis for analyzing surface texture of machined surfaces using wavelet filter. The multiscale surface features are analyzed using wavelet filter to explore the potential use of wavelet filter in monitoring of manufacturing process and feature detection in engineering surfaces.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Brain natriuretic peptide measurement in pulmonary medicine.

Summary Serum levels of natriuretic peptides are well established as important biomarkers in patients with cardiac disease. Less attention has been placed on the role of natriuretic peptides in patients with pulmonary conditions. In several well-defined groups of patients with pulmonary disease natriuretic peptides provide the clinician with clinically valuable information. A limitation of the interpretation of natriuretic peptides in pulmonary disease is the confounding effect of concurrent conditions such as heart failure, hypoxia, sepsis and renal failure. The present paper reviews the role of natriuretic peptides for diagnosis, risk stratification and prognosis of several pulmonary disorders.
Interplay and influence of thermomechanical stress in copper-filled TSV interposers

In this paper we use finite element simulations to determine the influence of two key design parameters on the thermomechanical stress and the stress interplay in copper-filled TSV arrays. The two parameters are the via's pitch-to-diameter ratio and thickness-to-radius (aspect) ratio. Our analytical results has suggested that the in-plane stress interplay becomes insignificant when the TSV pitch is at least five times of the via's radius. This criterion will be numerically verified in this paper. This work also suggests that it would be inadequate to approximate the thermomechanical stress into a simplified 2D models even for a small H/D ratio (which resembles a think, 2D-like structure).
Endor detection of charge density redistribution accompanying the ferroelectric transition in KH2PO4

Abstract ESR and electron nuclear double resonance (ENDOR) measurements have been carried out on SeO3- 4 - doped KH2PO4 to probe changes in the charge density distribution at the various atomic nuclei of the PO3- 4 unit. ESR measurements of the proton superhyperfine coupling show that in the paraelectric phase all four oxygens carry a time averaged spin density of about 0.18 but ESR resolution is insufficient for studies in the ferroelectric phase. ENDOR data show that in the ferroelectric phase, the spin density becomes ≈0.3 at the two oxygens near which the hydrogens localize, and only 0.05 on the other two. These results appear to support the theoretical model proposed by Bystrov and Popova,3 according to which the spontaneous polarization of the KH2PO4-type of compounds originates from the charge imbalance in the P—O bonds caused by proton localization, rather than the relative displacements of the K and P atoms. The new results also help understand the long-standing question as to why the magnitudes ...
Viscous fingers in porous media.

We consider the formation of viscous fingers in porous media using the boundary-integral method with particular application to a recent experiment involving a Hele-Shaw cell filled with glass beads. When the less viscous fluid wets the beads we can account for the patterns as ordinary viscous fingers in the presence of large noise.
Cathelicidin-deficient (Cnlp -/- ) mice show increased susceptibility to Pseudomonas aeruginosa keratitis.

Purpose To examine the clinical progression and innate immune responses during Pseudomonas aeruginosa (PA) keratitis in cathelicidin-deficient (KO) mice. Methods PA (ATCC 19660) keratitis was induced in KO mice and wild-type (WT) littermates generated on a 129/SVJ background. Clinical score and histopathology were used to monitor the progression of infection at postinfection (PI) days 1, 3, 7, 14, and 21. Mouse corneas were harvested for viable bacteria quantitation, and myeloperoxidase (MPO) assays were performed to determine the number of infiltrating neutrophils. ELISA was used to quantitate interleukin (IL)-1beta, IL-6, macrophage inflammatory peptide (MIP)-2, keratinocyte-derived chemokine (KC), tumor necrosis factor (TNF)-alpha, and vascular endothelial growth factor (VEGF) levels in the corneas. Results WT mice were resistant (cornea healed), whereas KO mice showed increased susceptibility (corneas failed to recover by 21 days or perforated) to PA infection. Clinical scores were significantly elevated in the infected corneas of KO mice versus WT mice at 7, 14, and 21 days PI. Absence of cathelicidin resulted in significantly delayed clearance of PA in the cornea and an increased number of infiltrating neutrophils at 1, 3, 7, and 14 days PI. KO mice also exhibited differential expression of protein levels for IL-1beta, IL-6, MIP-2, KC, TNF-alpha, and VEGF up to day 21 PI compared with the WT mice. Conclusions Cathelicidin-deficient mice showed considerable susceptibility to PA keratitis. The present study demonstrates direct in vivo evidence that endogenous expression of cathelicidin provides defense against corneal PA infection indicating its importance in host innate immunity at the ocular surface.
Estimation of variance of housing prices using spatial conditional heteroskedasticity (SARCH) model with an application to Boston housing price data

Abstract In this paper we investigate housing price volatility within a spatial econometrics setting. We propose an extended spatial regression model of the real estate market that includes the effects of both conditional heteroskedasticity and spatial autocorrelation. Our suggested model has features similar to those of autoregressive conditional heteroskedasticity (ARCH) in the time-series context. We utilize the spatial ARCH (SARCH) model to analyze Boston housing price data used by Harrison and Rubinfeld (1978) and Gilley and Pace (1996) . We show that measuring the variability of housing prices is an important issue and our SARCH model captures the conditional spatial variability of Boston housing prices. We argue that there is a different source of spatial variation, which is independent of traditional housing and neighborhood characteristics, and is captured by the SARCH model.
A perturbation molecular orbital theory of gas-phase dissociative electron-transfer rates

Gasphase dissociative electron-transfer (ET) reactions are examined in the light of modern electron-transfer theory and a perturbation molecular orbital (PMO) model for ion-molecule collision rates. Two dissociative ET reactions reported by Knighton and Grimsrud—the reaction of azulene anion with dibromodifluoromethane and with carbon tetrachloride—happened in the inverted region of the relationship between reaction rate and free energy. Carbon-halogen vibration participation in dissociative ET reactions is demonstrated in two reaction series. Carbon-hydrogen stretch (3050 cm−1) activation of electron transfer happened in the most exothermic reaction series: dissociative capture to form bromide from bromotrichloromethane The reasons for the failure of classical ion-molecule collision theory to give a quantitative account of reactive ion-molecule collision rates are presented in some detail. The fundamental failure is a result of a previously unappreciated change in the polarizability of a molecule when the orbitals on the molecule overlap with those on an adjacent ion. The molecular orbital-based collision model used here avoids the need to evaluate the changes in the polarizability tensor with overlap.
Symmetries of spontaneous decay for atoms near any surface

Abstract The structure of spontaneous decay of atoms in the vicinity of a surface is shown to be determined by spatial symmetries. The spontaneous-decay operator for a degenerate two-level atom is derived, and with symmetry considerations the number of free parameters is reduced to two. Only the dimensionless and normalized inverse lifetimes b ∥ and b ⊥ for a parallel and perpendicular dipole moment with respect to the surface, respectively, enter the expression for the relaxation operator for any atom near any surface. These two parameters incorporate the atom-surface distance dependence of all Einstein coefficients for spontaneous decay, and all optical properties of the substrate material. It is shown that the specific features of spontaneous decay are mainly geometrical, and a consequence of symmetries of the vacuum radiation field, irrespective of the presence of the atom. With an example it is shown how the parameters b ∥ and b ⊥ can be calculated in a particular case.
English Learner "Curricular Streams" in Four Middle Schools: Triage in the Trenches.

Little is known about the curricular experiences schools provide English learner students (ELs) to meet the dual goals of attaining English language proficiency (ELP) and grade-level achievement. I introduce the concept of Curricular Streams to provide a more nuanced comparative analysis of four urban middle schools, focusing on: (a) the extent to which they provided English language development (ELD) instruction and access to the core and full curriculum; and (b) the relative emphasis on ELP versus core academic content, remediation versus acceleration, and isolation versus integration of ELs with non-EL peers. I situate the Curricular Streams within the schools’ broader cultures and practices. The results reveal local definitions of EL status and wide variation in EL Curricular Streams: One school emphasized ELP and remediation over access to the core. Another integrated ELs more quickly into mainstream courses, yet its remediation emphasis limited access to the core. The third provided more access, but isolated ELs. The fourth provided more access to the core, accelerated ELD, and eschewed interventions. The evidence suggests that schools are groping for solutions and it raises questions about the efficacy of EL state policy that relies on local control for interpretation. I provide implications for research, policy, and practice and hypotheses about the characteristics of Curricular Streams and school cultures that might increase ELs’ opportunity to learn and achieve the dual goals.
Re: Sørensen et al.: low dose aspirin.

TO THE EDITOR: Dr. Sorensen and his group (1), in a retrospective analysis of low dose aspirin at the level of 150 mg/day, note the risk of upper GI bleeding with the low dose aspirin and other nonsteroidal drugs is high, at a rate ratio of 5.6, whereas the rate ratio is 2.6 in users of noncoated low dose aspirin as well as coated low dose aspirin. This study done retrospectively suggests that prophylactic low dose aspirin carries an increased risk of GI bleeding irrespective of whether it is coated or uncoated.
Evidence that Teacher Interactions with Pedagogical Contexts Facilitate Chemistry-Content Learning in K-8 Professional Development.

In many innovative science content professional development (PD) courses for teachers, science concepts are situated within pedagogical contexts, or in other words, science content is incorporated within contexts relevant to teaching and student learning. Pedagogical contexts are often used because they are believed to be engaging for teachers and to support content transfer to the classroom. However, few studies have investigated how pedagogical contexts serve to impact teacher engagement and science content learning. This qualitative case study examined K-8 in-service teachers’ interactions with pedagogical contexts in a chemistry PD course. Findings indicate that teachers’: (1) contribution of teaching experiences helped create a collegial learning environment, (2) sharing of concerns from classroom teaching directed content discussion and learning objectives, and (3) reflection on teacher and learner roles in the PD classroom led to persistence in chemistry-content learning. Implications for PD instructor use of pedagogical contexts in science content based PD are discussed.
Surfactant effects on α-factors in aeration systems

Aeration in wastewater treatment processes accounts for the largest fraction of plant energy costs. Aeration systems function by shearing the surface (surface aerators) or releasing bubbles at the bottom of the tank (coarse- or fine-bubble aerators). Surfactant accumulation on gas-liquid interfaces reduces mass transfer rates, and this reduction in general is larger for fine-bubble aerators. This study evaluates mass transfer effects on the characterization and specification of aeration systems in clean and process water conditions. Tests at different interfacial turbulence regimes show higher gas transfer depression for lower turbulence regimes. Contamination effects can be offset at the expense of operating efficiency, which is characteristic of surface aerators and coarse-bubble diffusers. Results describe the variability of alpha-factors measured at small scale, due to uncontrolled energy density. Results are also reported in dimensionless empirical correlations describing mass transfer as a function of physiochemical and geometrical characteristics of the aeration process.
Automated deployment and Aggregated access control for SOA composite applications

Modeling, assembling, deploying and managing composite applications built using service oriented architectures (SOA) present many interesting challenges. Among these challenges, we consider two: service deployment and security management for access control. In this application session, these challenges are explored in the context of a prototype banking application: "Jivaro". The Jivaro prototype has features such as automated and configurable business processes using BPEL and manual tasks, multitenancy using virtual portals, and security using LDAP. We focus on two specific management pain points: 1. the difficulty in deploying multiple SOA components into multiple target middleware containers, and 2. inconsistency in access control policies for multi-tier applications. For addressing the deployment issues, we present a real-wo rid deployment scenario involving the use of ANT tasks and scripting interfaces. For addressing inconsistencies in access control policies, we present a solution using the XACML standard, a common authorization model developed as an extension of the Java authorization contract for containers and a common policy store and policy administration point. We compare and contrast current access control policies for J2EE containers and databases with the proposed new common authorization model. We also compare separate access control policy stores versus the proposed solution for a common store. Our aggregated role based authorization model provides consistent access control policies that complement single sign-on and identity propagation schemes. This model also touches upon issues surrounding role and policy based management, specifically regarding the potential of combining security policy administrator roles for different tiers.
PM and PR forms of cytochrome c oxidase have different spectral properties

The reaction between bovine heart cytochrome c oxidase and dioxygen was monitored at room temperature in the visible and Soret regions following photolysis of the mixed-valence CO-bound enzyme. Time-resolved optical absorption difference spectra were collected between 50 ns and 1.7 ms by a gated multichannel analyzer. Singular value decomposition and global exponential fitting resolved three processes with apparent lifetimes of 2.2±0.5, 17±4 and 160±30 μs. The spectra of the intermediates were extracted based on a sequential kinetic mechanism and compared to the corresponding intermediate spectra observed during the reaction of the fully reduced enzyme with dioxygen. The first process is associated with a conformational change at heme a3 upon dissociation of CO from CuB+ and concomitant back-electron transfer from heme a3 to heme a. This is followed by O2 binding to heme a3 forming compound A (AM), with a spectrum identical to that observed upon O2 binding to heme a3 in the fully reduced enzyme (AR). Intermediate AM decays into PM, the spectrum of which is equivalent to that of the 607 nm form, generated upon addition of H2O2 to the oxidized enzyme at alkaline pH values (PH). However, the spectrum of PM is significantly different from the corresponding intermediate observed upon the reaction of dioxygen with the fully reduced enzyme (PR). The spectral differences between PM and PR may arise from the different number of redox equivalents at the binuclear site, with a tyrosine radical in the PM state, and tyrosine or tyrosinate in PR, or may be the consequence of a more complex reaction mechanism in the case of the fully reduced enzyme.
Resources for an Investigative and Sustainable Undergraduate Medicinal Chemistry Research Program

Medicinal chemistry, a field typically left to the graduate and commercial realm, can be an effective pedagogical tool at an undergraduate institution. The drug-discovery process can be used as a tool to provide a broad range of research experiences that includes the design, synthesis, and testing of novel small molecules as potentially new therapeutic agents. Herein we discuss our scientific and pedagogical efforts and detail some of the available resources that faculty working at primarily undergraduate colleges may find useful in their exploration of a medicinal chemistry-related research program.
High diffraction efficiency, broadband, diffraction crystals for use in crystal diffraction lenses

A major goal of the MAX program is to detect and measure gamma rays produced following the nuclear reactions that take place in a supernova explosion. To detect a reasonable number of supernovae, sensitivities of the order of a few times 10-7 γ cm-2sec-1 are needed — much better than possible with current instruments. The approach in the MAX program is to use a crystal diffraction lens to collect photons over a large area and concentrate them on a small well-shielded detector, greatly improving the signal to noise ratio. The crystals need to have both high diffraction efficiency and a relatively broad energy bandwidth. With mosaic crystals there is a trade-off between bandwidth and diffraction efficiency — one can have either high efficiency or large bandwidth, but not both without losing too much intensity through atomic absorption. A recent breakthrough in our understanding of crystal diffraction for high-energy gamma rays has made it possible to develop crystals that have both high diffraction efficiency and a relatively broad energy bandwidth. These crystals have near perfect crystal structure, but the crystalline planes are slightly curved. Such curved planes can be obtained in 3 different ways, by using mixed crystals with a composition gradient, by applying a thermal gradient, and by mechanically bending a near perfect crystal. A series of experiments have been performed on all three types of crystals using high-energy x-ray beams from the Advanced Photon Source at the Argonne National Laboratory. Experiments performed at 3 energies, 93 keV, 123 keV and 153 keV, with both the thermal gradient Si crystals and with the mechanically bent Si crystals, demonstrated that one can achieve diffraction efficiencies approaching 100% with moderate energy bandwidths (ΔE/E=1.4%) and low atomic absorption (transmission = 0.65), in excellent agreement with theory. The use of this type of diffraction crystal is expected to increase the sensitivity of gamma ray telescopes by a factor of 5 over that possible with normal mosaic crystals.
The effect of cell monolayer density on the cytotoxicity metal ions which are released from dental alloys

The effect of cell density (number of cells per unit area of a monolayer culture) on the in vitro cytotoxicity of metal ions which are known to be released from dental materials was investigated. The effects of cell density (1) may explain previous discrepancies in in vitro tests, (2) may be important in wound healing where cell density changes over time, and (3) may help clarify the mechanisms of cytotoxicity of metal ions. Balb/c 3T3 fibroblasts were plated at cell densities ranging from 10,000-80,000 cells/cm2 and were exposed to 8 concentrations of 10 different metal ions. After 24 h, the succinic dehydrogenase activity and DNA synthesis were measured to quantify the cytotoxic effect. Higher cell densities markedly reduced the sensitivity of these fibroblasts to all metal ions except Al+3 and Zn+2, but the magnitude of the reduction was metal dependent. In addition, the DNA synthesis was inhibited more than the succinic dehydrogenase activity for all metal ions except Zn+2. The unique effect of cell density on each metal ion supported the hypothesis that the effect was not simply caused by a dilution of the number of metal ions per cell. Given these results, the effect of cell density should be carefully selected in in vitro cytotoxicity tests.
Hybridization effects — The evolution from non-magnetic to magnetic behavior in uranium-based systems☆

Abstract Hybridization of the f electrons with the conduction electrons and f electrons on adjacent ions drives the rich non-magnetic to magnetic behavior observed within the lighter actinides and intermetallic compounds containing these elements. Within and near this transition region, many of the very challenging problems associated with narrow band phenomena occur, e.g. strong spin fluctuations, spin glass behavior, itinerate magnetism, Kondo effect and heavy fermion behavior. Measurements of the temperature dependence of the specific heat, electrical resistivity and magnetic susceptibility are presented for several uranium-based pseudobinary alloy systems which display a substantial variation in f-f overlap and/or f conduction electron hybridization. Such studies clearly display the role hybridization plays in the very interesting and varied features reported for these systems.
Expanding the repertoire of reference

In the literature of librarianship, the education of a reference librarian has, on the whole, meant two things. First, it has referred to the theoretical and/or practical training in reference services that a student receives in library school. Second, it has meant the training, or lack of it, the new librarian receives in making the transition from library school to the reference desk. What reference education has not meant, to judge by the literature, is the ongoing training or professional development a working reference librarian might receive on the job.
Wall Cooling Effects on Hypersonic Transitional/Turbulent Boundary Layers at High Reynolds Numbers

The characteristics of a thick hypersonic boundary layer turbulent for a length of 175 cm on a 4 deg sharp wedge were measured. The resulting boundary layer was free from transverse curvature effects and only mildly affected by upstream history effects caused by pressure and wall temperature gradients. Heat-transfer distributions were used to locate regions of laminar, transitional, and turbulent flow at an edge unit Reynolds number of 470,000 cm at wall-to-total temperature ratios from about 0.3 to 1. Wall cooling had little effect on the location of the transition region. Pitot and total temperature profiles and skin-friction measurements were obtained at several locations along the model longitudinal centerline. Mixing length and turbulent Prandtl number distributions were derived from the fully turbulent mean profiles.
Wave-ering: An ERP study of syntactic and semantic context effects on ambiguity resolution for noun/verb homographs

Two event-related potential experiments investigated the effects of syntactic and semantic context information on the processing of noun/verb (NV) homographs (e.g., park). Experiment 1 embedded NV-homographs and matched unambiguous words in contexts that provided only syntactic cues or both syntactic and semantic constraints. Replicating prior work, when only syntactic information was available NV-homographs elicited sustained frontal negativity relative to unambiguous words. Semantic constraints eliminated this frontal ambiguity effect. Semantic constraints also reduced N400 amplitudes, but less so for homographs than unambiguous words. Experiment 2 showed that this reduced N400 facilitation was limited to cases in which the semantic context picks out a non-dominant meaning, likely reflecting the semantic mismatch between the context and residual, automatic activation of the contextually-inappropriate dominant sense. Overall, the findings suggest that ambiguity resolution in context involves the interplay between multiple neural networks, some involving more automatic semantic processing mechanisms and others involving top-down control mechanisms.
The Role of Juvenile Hormones in Crustacean Reproduction

Synopsis. Similar to juvenile hormone production in adult insects, the production of methyl farnesoate (MF) seems to be related to reproduction in both sexes in mature crustaceans. The mandibular organ (MO) synthesizes MF, and its activity corresponds to reproductive stages. High MF levels in the blood are found in vitellogenic females and reproduc? tively active males. Conversely, low levels are found in immature females, non-vitellogenic females, and males that are in reproductive diapause. The MO is under inhibitory control by neurosecretory factors from the sinus gland located in the eyestalks, and may be stimulated by factors from the brain and/or thoracic ganglion.
Determining camera parameters from the perspective projection of a quadrilateral

Abstract In this paper we show that there is sufficient information in the two-dimensional perspective projection of an arbitrary quadrilateral of known shape and size in three-space to determine the exact three-dimensional coordinates of its vertices, generalizing known results for rectangles. Implementation results are also discussed.
An examination of people's republic of China business negotiating behaviors

Because of rapid economic development in the People's Republic of China (PRC), there is a need for information about the negotiating behaviors of PRC business people. Such information can help to ensure successful business transactions. This study examines PRC business negotiating behaviors by conducting in‐depth interviews with 16 Hong Kong business persons who have experience doing business with PRC Chinese. Questions regarding cultural factors that affect PRC business negotiations and problems encountered with PRC Chinese are asked. Overall, participants identify relation (guanxi), face, harmony, reciprocity, credibility, authority, patience, and status as eight important cultural factors that affect PRC business negotiations. Explanations of these factors are reported.
Ultrafast Optical-Field Controlled Photoemission from Plasmonic Nanoparticle Arrays

Exciting plasmonic nanoparticles with few-cycle optical pulses, we observe photoemission across few-micron gaps under ambient conditions. The photoemission current is modulated by the carrier-envelope phase of the excitation pulse.
Assisted Suicide and Euthanasia: Arguments For and Against Practice, Legalization and Participation

SUMMARYConceptual and pragmatic arguments are presented supporting and opposing the following topics: the practice of suicide, assisted suicide, and voluntary active euthanasia; the legalization of assisted suicide or euthanasia; and the participation of physicians in these acts (whether or not they are legalized). Safeguards for physician-assisted suicide and euthanasia are proposed. The morally problematic role of the pharmacist in physician-assisted suicide and euthanasia is discussed as are appropriate responses of healthcare professionals to the public's demand for assistance in suicide and euthanasia.
Long-term stability of maternal prenatal steroid hormones from the National Collaborative Perinatal Project: Still valid after all these years

Large epidemiological samples, including the National Collaborative Perinatal Project (NCPP), in which blood/serum was collected during pregnancy and offspring followed longitudinally, offer the unique opportunity to examine neuroendocrine mechanisms underlying prenatal "programming" of adult health and disease. However, in order to conduct longitudinal analyses, it is critical to determine the validity of maternal prenatal samples stored over long periods. We investigated the validity of cortisol, testosterone, and their binding globulins (corticosteroid-binding globulin (CBG) and sex hormone-binding globulin (SHBG)) in maternal prenatal serum from the NCPP after over 40 years of storage. Study 1 included 64 maternal serum samples collected on the day of delivery; study 2 involved 1099 third trimester serum samples collected between gestational weeks 31 and 36. Across both studies, cortisol and testosterone concentrations were consistent with values from published studies of fresh samples collected at similar points in gestation. CBG and SHBG were present, but showed some differences from published studies. Results support the validity of cortisol and testosterone values following 40+ years of storage. Results also provide validation for future longitudinal tests of prenatal "programming" hypotheses within the NCPP. Stability of steroid hormones over decades suggests that stored samples from other longitudinal studies may also allow opportunities to investigate links between prenatal steroids and long-term offspring outcomes.
Internet Privacy and Security: An Examination of Online Retailer Disclosures

Abstract The Federal Trade Commission has declared the privacy and security of consumer information to be two major issues that stem from the rapid growth in e-commerce, particularly in terms of consumer-related commerce on the Internet. Although prior studies have assessed online retailer responses to privacy and security concerns with respect to retailers’ disclosure of their practices, these studies have been fairly general in their approaches and have not explored the potential for such disclosures to affect consumers. The authors examine online retailer disclosures of various privacy- and security-related practices for 17 product categories. They also compare the prevalence of disclosures to a subset of data from a consumer survey to evaluate potential relationships between online retailer practices and consumer perceptions of risk and purchase intentions across product categories.
EFFECTS OF CHLOROTRIFLUOROETHYLENE OLIGOMER FATTY ACIDS ON RECOMBINANT GABA RECEPTORS EXPRESSED IN XENOPUS OOCYTES

GABA-activated Cl− current was expressed in Xenopus oocytes after injecting cRNA that had been transcribed in vitro from complementary DNA (cDNA) coding for a single GABA ρi-subunit cloned from human retina. The expressed current was insensitive to 100 μm bicuculline, but was activated by the GABA analogue trans-4-aminocrontonic acid (TACA). Anion-selective permeability of the expressed ρ1-subunit was determined by isotonically replacing the extracellular Cl− with different anions. The anion permeability was very similar to the native GABAA receptor/channel following a sequence of SCN− > I− > NO3 − > Br−≥ Cl−. Halogenated fatty acids, such as chlorotrifluoroethylene (CTFE) and perfluorinated oligomer acids inhibited the GABA-induced current in oocytes expressing the human retinal GABA ρ1-subunit or rat brain GABAA receptor α1,β2,γ2 subunits. The inhibitory effect of halogenated fatty acids demonstrated a carbon chain length-dependent manner of: C10 > C8 > C6 > C4. Perfluorinated C8-oligomer acid (PFOA) was less effective at blocking this channel than the C8-CTFE oligomer acid. Radiolabeled GABA binding assay indicated that CTFE oligomer acids do not interfere at the GABA binding site of the receptor. Furthermore, the C8-CTFE oligomer fatty acid did not compete with picrotoxin for binding sites within the pore of the channel. These studies demonstrated that the heterologous expression system is useful for studying the molecular interaction between potential neurotoxic agents and neuroreceptors. Our results provide detailed information that should contribute to our understanding of the structure and function of retinal GABA receptors.
Simple algorithm for improved security in the FDDI protocol

We propose a modification to the Fiber Distributed Data Interface (FDDI) protocol based on a simple algorithm which will improve confidential communication capability. This proposed modification provides a simple and reliable system which exploits some of the inherent security properties in a fiber optic ring network. This method differs from conventional methods in that end to end encryption can be facilitated at the media access control sublayer of the data link layer in the OSI network model. Our method is based on a variation of the bit stream cipher method. The transmitting station takes the intended confidential message and uses a simple modulo two addition operation against an initialization vector. The encrypted message is virtually unbreakable without the initialization vector. None of the stations on the ring will have access to both the encrypted message and the initialization vector except the transmitting and receiving stations. The generation of the initialization vector is unique for each confidential transmission and thus provides a unique approach to the key distribution problem. The FDDI protocol is of particular interest to the military in terms of LAN/MAN implementations. Both the Army and the Navy are considering the standard as the basis for future network systems. A simple and reliable security mechanism with the potential to support realtime communications is a necessary consideration in the implementation of these systems. The proposed method offers several advantages over traditional methods in terms of speed, reliability, and standardization.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Testing and Evaluation of Insulating Films Part II: Test Results Using Facilities at the University at Buffalo

In this second part of a two-part article, representative data using the insulation test facilities at the University at Buffalo is presented. It is also shown how this data is useful toward the design of reliable high voltage systems.
Acquired hydrocephalus associated with superior vena cava syndrome in infants

We report observations on children with the unusual combination of superior vena cava syndrome in infancy followed by communicating hydrocephalus. Following retrospective review of hospital discharges at a tertiary children's hospital, three children were identified in a 13-year period. Two term infants were treated with extracorporeal membrane oxygenation for pulmonary failure associated with congenital diaphragmatic hernia. These infants had septic complications of central venous lines. A post-term infant required reconstruction of the superior vena cava following cannulation for cardiac bypass surgery to repair transposition of the great vessels. Thrombosis occurred and was followed by the sequential development of superior vena cava syndrome and communicating hydrocephalus. The findings in these patients suggest that communicating hydrocephalus may be caused by superior vena cava syndrome. This is an unusual complication of therapeutic manipulation of the heart and great veins. Cerebrospinal fluid shunting may be required.
Near- and far-regions of mode splitting in coupled magnetic resonators and use in passive ranging

The monostatic backscattered magnetoquasistatic field coupling measured at the terminals of a resonant coil due to strongly coupled magnetic resonance (SCMR) coupling with a nearby passive resonant coil exhibits dual orthogonal mode splitting. The difference between the center frequencies of the orthogonal modes, known as the coupled mode frequency split, is sensitive to range of the nearby passive resonant coil. Near- and far-region relationships are derived for the SCMR coupling which are important in practical passive magnetoquasistatic systems. Measurements of this frequency split is presented and inverted for range using the exact theory. The results are compared to inversions using the near- and far-region solutions.
Identification of a hydrodynamic threshold in karst rocks from the Biscayne Aquifer, south Florida, USA

A hydrodynamic threshold between Darcian and non-Darcian flow conditions was found to occur in cubes of Key Largo Limestone from Florida, USA (one cube measuring 0.2 m on each side, the other 0.3 m) at an effective porosity of 33% and a hydraulic conductivity of 10 m/day. Below these values, flow was laminar and could be described as Darcian. Above these values, hydraulic conductivity increased greatly and flow was non-laminar. Reynolds numbers (Re) for these experiments ranged from <0.1 to 7. Non-laminar flow conditions observed in the hydraulic conductivity tests were observed at Re close to 1. Hydraulic conductivity was measured on all three axes in a permeameter designed specifically for samples of these sizes. Positive identification of vertical and horizontal axes as well as 100% recovery for each sample was achieved. Total porosity was determined by a drying and weighing method, while effective porosity was determined by a submersion method. Bulk density, total porosity and effective porosity of the Key Largo Limestone cubes averaged 1.5 g/cm3, 40 and 30%, respectively. Two regions of anisotropy were observed, one close to the ground surface, where vertical flow dominated, and the other associated with a dense-laminar layer, below which horizontal flow dominated.
Deep brain stimulation of the subthalamic nucleus for peripherally induced parkinsonism.

RESULTS Trauma to the peripheral nervous system can cause various movement disorders including dystonia, tremor and parkinsonism. Most patients with peripherally-induced parkinsonism develop symptoms that extend beyond the original site of injury, suggesting involvement of the central nervous system, possibly through reorganization in response to altered peripheral input. Most patients with peripherally-induced parkinsonism do not respond to levodopa therapy.
Effects of the N-Methyl-D-Aspartate Receptor on Temporal Summation of Second Pain (Wind-up) in Irritable Bowel Syndrome

Abstract Irritable bowel syndrome (IBS) is a common gastrointestinal disorder in which the pathophysiological mechanisms of the pain and hypersensitivity are not well understood. IBS patients frequently complain of pain in body regions somatotopically distinct from the gut, suggesting that central hyperalgesic mechanisms may be involved. In the current study, during the wind-up testing session, a series of 6 heat pulses were presented with an interstimulus interval (ISI) of 3 seconds. Following the 1st, 3rd, and 6th thermal stimuli, subjects were asked to rate the late thermal sensation or second pain. IBS patients who demonstrated temporal summation of pain (TSSP) then received dextromethorphan and placebo in a randomized, double-blind, fashion to block wind-up. The results showed: 1) a subset of IBS patients, but not controls, showed TSSP in response to a series of noxious heat pulses; and 2) TSSP was blocked by administration of dextromethorphan, an NMDA receptor antagonist. In summary, these findings further elucidate mechanisms of somatic hypersensitivity in a subset of IBS patients. Our results also support an etiologic basis for abnormal NMDA receptor mechanisms in some IBS patients. Future studies are needed to determine if NMDA receptor antagonists may be used to treat IBS patients. Perspective This study evaluates temporal summation of second pain in a subset of IBS patients that is blocked by Dextromethorphan, an NMDA receptor antagonist. Theses results could lead to the use of an NMDA receptor antagonist in the treatment of pain in a subset of IBS patients.
Paleoecological problems of Mg and Sr in biogenic calcites in light of recent thermodynamic data

Calcitic shells of three species of the ostreid pelecypods, Exogyra cancellata, E. costata (Late Cretaceous) and Crassostrea virginica (Recent) were analyzed for Mg and Sr. Shells of Exogyra contain 0.5–1.5 mole per cent MgCO3, 0.04–0.13 mole per cent SrCO3; shells of Crassostrea—1.0–1.6 mole per cent MgCO3, 0.08–0.09 mole per cent SrCO3. These calcites are not at equilibrium with the (aMg++)(aCa++) ratio as in the Recent sea water. The concentrations of Sr in the skeletons of these species and of Belemnitella americana (Late Cretaceous) can, at least in part, be accounted for by Nernst's distribution equilibria with respect to the SrCa ratio as in the Recent seas. A combined record of Mg and Sr, treated as an incomplete ternary free energy surface, may accentuate differences between geographically distinct populations. Interpretation of such differences is at present impeded by a lack of exact knowledge of the genetic and environmental effects on the skeletal chemistry. Approximate calculation of the activity coefficients of the components in magnesian calcites at 25°C is given in the Appendix.
Predicting the anatomical position of the palatal root apex in maxillary first premolars during surgical endodontic treatment.

Abstract Introduction Although many studies have reported on the morphology of maxillary first premolars, to our knowledge, there has never been an investigation reporting the anatomic position of the palatal (P) root tip relative to the B root tip in mesiodistal (MD), buccopalatal (BP), and apicocoronal (AC) dimensions. Such information could help clinicians more accurately locate root apices, reduce surgical morbidity, and improve the precision and prognosis of endodontic periradicular surgery for this tooth. Methods Fifty extracted, bifurcated, human maxillary first premolars were individually mounted and photographed under 10× magnification and oriented to simulate a clinical view. Results The P apex was superimposed by the B apex in 25 of 50 specimens, distal to the B apex in 24 of 50, and mesial to the B apex in only 1 instance. When not superimposed by or mesial to the B apex, the P apex was usually 1.4 ± 0.7 mm distal to the B apex. In 98% of specimens, the P apex was positioned palatocoronal or palatocoronodistal to the B apex. Conclusions This knowledge can be used to clinically minimize the size of osteotomies required to locate P root apices during endodontic surgery.
Oscillations in sea temperature at Scripps and oceanside piers

Abstract Observations of sea temperature have been made in the vicinity of two southern California coastal piers some 40 km apart. Temperature-depth curves and temperature profiles show a shallow thermocline during the warm months. The depth of the thermocline varies with time, and, as a result, thermograms from fixed depths at the pier ends show oscillations. Changes of 5 C over a time interval of hours (Fig. 1) are frequent as the intersection of the thermocline with the sloping bottom moves inshore and offshore. Thermograms from the two piers show no obvious coherence in the oscillations, but over a distance of 4 km along the Scripps shore there is evidence of coherence. Oscillations in the thermograms suggest the possibility of tidal periodicities but without the persistent regularity demonstrated for surface tides. An internal wave mechanism is consistent with the data. Internal waves have been confirmed in deeper water in the general area, and the oscillations can, therefore, represent the effect near the shore of internal waves of various periods, including tidal. Applications to marine biology, underwater sound, and sedimentation are mentioned. It is suggested that coastal piers offer bases for economical operation of gauges which will help to determine the existence and nature of internal-tide waves.
Oscillatory and Monotonic Polarization. The Polarization Contribution to the Hydration Force

The propagation of polarization in water, in the vicinity of a planar surface containing dipoles, is considered to be a consequence of the nonuniformity of the dielectric constant near the dipoles. Discrete finite difference equations have been derived by assuming a layered icelike structure. These equations predicted a polarization that oscillates with the distance from the surface. When the polarizing surface was considered rough or fluctuating, the oscillations were smoothed out and a monotonically decaying average polarization was obtained. Assuming that there are local icelike structures around any of the water molecules, a second-order differential equation for the polarization and expressions for its decay length were derived.