cssi/SciSciGPT-SciSciNet huggingface dataset:
Modelling square-wave pulse regulation

The characteristic hypothalamus square-wave secretion and its regulation of the pituitary are essential for the optimal functioning of the menstrual cycle. Here we consider two coupled models, where one mimics the square-wave secretion and the second, a self-replication chemical system, represents a regulated subsystem. We analyse the relation of the period and amplitude of the square-wave oscillations on the secondary oscillator, finding that both period and amplitude shape the secondary oscillations. Furthermore, a combined slow change of both period and amplitude are required for biologically suitable product concentrations of the secondary oscillator.
An enhancer sequence from bovine papilloma virus DNA consists of two essential regions

A comprehensive structural analysis of an enhancer sequence from bovine papilloma virus DNA is presented based on the construction and functional analysis of 20 mutant derivatives. The results, obtained in CV-1 tissue culture cells, show that this enhancer is a small genetic element--only 40 bp in length--that contains two essential regions. The two regions exhibit homology to each other and to DNA fragments from other viral genomes that also act as enhancers in the assay used. However, there is a certain latitude in the sequences that have enhancer activity in CV-1 cells, even within the critical regions. The results are discussed with respect to the model that enhancers are binding sites for tissue specific transcription factors. The formation of Z-DNA might be involved in the enhancement process. However, single base pair transitions in an 8 base pair stretch of alternating purines and pyrimidines within the BPV enhancer which conserve this pattern destroy enhancer function.
Abstract 1028: Role of Hsp90 in the stability of EGFR from radiation and cisplatin-induced degradation.

Heat-shock protein 90 (Hsp90) is an evolutionary conserved eukaryotic molecular chaperone that has a large number of clients including signaling molecules such as EGFR. Induction of Hsp90 upon cellular stress induced by radiation or chemotherapy can enhance stabilization of its clients which may lead to resistance to therapy and can often provide an environment for metastasis. Therefore, targeting Hsp90 has been shown to be a potential therapeutic approach to induce EGFR degradation and block metastatic spread. The aim of this study is to further understand the mechanism of Hsp90 induction and its post-translational modifications within cancer cells as well as its microenvironment and their significance in EGFR protein stability. We hypothesized that activation of Hsp90 upon cellular stress induced by radiation and chemotherapy provides stability to EGFR not only in cancer cells, but also in tumor-associated endothelial cells, which allows cancer cell survival and metastatic spread by increasing EGFR (and other clients) stability. Our preliminary data indicate that an enhancement in EGFR protein interaction with Hsp90 in both endothelial cells and head and neck cancer cell lines correlate with cell survival upon radiation or cisplatin treatment. Cisplatin treatment also caused an increase in Hsp90 activation as reflected by an increase in ATP binding activity. Increase in EGFR phosphorylation led to a decrease in its interaction with Hsp90. We also found that inhibition of Hsp90 activity reduced this interaction, which decreased EGFR half-life and promoted cell-death in cancer and endothelial cells. We are now extending our research efforts to understand the effects of radiation and cisplatin on the post-translational modifications of Hsp90 such as phosphorylation and its potential role in binding with EGFR. The long-term goal of this study is to develop a specific protein-protein interaction antagonist (PPI) to induce selective EGFR degradation and block the survival and metastatic spread regulated by EGFR. Citation Format: Ameer L. Elaimy, Aarif Ahsan, Dipankar Ray, Theodore S. Lawrence, Mukesh K. Nyati. Role of Hsp90 in the stability of EGFR from radiation and cisplatin-induced degradation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1028. doi:10.1158/1538-7445.AM2013-1028
John W. Salter, Sir William Logan, and Elkanah Billings: A Brief British Involvement in the First Decade of ‘Canadian Organic Remains’ (1859)

John W. Salter, paleontologist of the Geological Survey of Great Britain, and son-in-law of J. de C. Sowerby, was commissioned by Director William Logan to describe and illustrate Canadian fossils. The fossils were given to Salter in 1851 but publication did not take place until 1859. Decade I of Canadian Organic Remains by Salter was illustrated by steel engravings. This particular technology is virtually forgotten today, but despite difficulties in preparation eventually produced outstanding illustrations. Elkanah Billings, hired by Logan in 1856 as the first Canadian government palaeontologist, journeyed to Great Britain shortly after his appointment and studied with Salter. Billings produced the third Decade, but the first one to be published. Comparison of the Decades to similar publications of the times indicates that they accomplished Logan's goal of making Canadian fossils better known.
Maturation of epileptiform activity

Abstract 1. 1. Penicillin is an effective epileptogenic agent in neonatal rabbits. 2. 2. Newborn rabbit's cerebral cortex possesses a definite but limited capacity to produce epileptiform activity. 3. 3. The main characteristic of newborn cerebral cortex in response to penicillin is a marked variability in duration of the paroxysmal activity. 4. 4. Maturation of epileptiform activity shows a time course consistent with increased neuronal hypersynchrony reaching adult spike characteristics by the third post-natal week. 5. 5. The epileptogenic focus in the newborn rabbit projects to the contralateral hemisphere in a limited, inconstant manner during the first post-natal week. The capacity to sustain an electrographic seizure discharge develops by the second post-natal week.
Central projections of the spiral ganglion of the squirrel monkey

For establishing the relationships of the central projections of the spiral ganglion with the cytoarchitectural regions of the cochlear nuclear complex in a primate species, 23 squirrel monkeys, Saimiri sciureus were utilized. Restricted lesions of the cochlea were confirmed histologically and the resulting degeneration was traced to the cochlear nuclei in sections prepared with Nauta (′57) and Fink-Heimer (′67) technics. By following the course of degeneration, the cochlear root fibers can be seen to bifurcate into ascending and descending branches. The ascending branches from the apical through basal turns of the spiral ganglion terminate in a rostro-lateral to caudo-medial gradient in the anteroventral cochlear nucleus. The descending branches from the apical through basal segments of the spiral ganglion terminate in a ventral to dorsal pattern in the posteroventral and dorsal cochlear nuclei. Ascending branches terminate chiefly on large and small spherical cells and globular cells in the anteroventral region. Terminals of descending branches are associated with globular, multipolar and octopus cells of the posteroventral nucleus and cells of the central and granular layers of the dorsal cochlear region.
Cortical Substance P-Like Immunoreactivity in Cases of Alzheimer's Disease and Senile Dementia of the Alzheimer Type

: The concentration of substance P-like immunoreactive material (SPLI) and somatostatin-like immunoreactive material (SLI) and the activity of acetyl-CoA: choline-O-acetyltransferase (ChAT; EC 2.3.1.6.) were measured in eight brain regions of 13 normal patients and 12 patients with Alzheimer disease/senile dementia of the Alzheimer type (AD/SDAT). SPLI was significantly lower in five of eight regions in the patients with AD/SDAT. Younger patients with AD/SDAT had significantly lower SLI in the parietal cortex than older patients. ChAT activity and SPLI in the parietal cortex of the presenile patients with ADISDAT were not significantly different from values found in older patients.
Pain Responder Analysis: Use of Area Under the Curve to Enhance Interpretation of Clinical Trial Results

Interpretation of results on patient-reported pain outcomes from clinical trials should be meaningful to patients and healthcare providers. This study applied an area-under-the-curve (AUC) analysis to responder profiles in a clinical trial of pregabalin for the treatment of fibromyalgia (FM). Data were from a 14-week, randomized, placebo-controlled trial of pregabalin (300, 450, or 600 mg/day) for the treatment of FM in patients meeting American College of Rheumatology criteria for FM and with a baseline pain score of at least 40 mm on the 100-mm pain visual analogue scale. Pain was evaluated in a daily diary by patients using an 11-point numeric rating scale (0 = no pain, 10 = worst possible pain). Response profiles on pain improvement scores and their differences between pregabalin and placebo were assessed using the AUC (derived using the trapezoidal rule) from the responder curve (vertical axis, proportion of subjects; horizontal axis, minimum percent improvement in pain). The AUC can be interpreted as if all responders were improved by the same percentage equal to the AUC divided by 100. The AUCs (2,100 for placebo, and 2,944, 3,170, and 3,349 for pregabalin 300, 450, and 600 mg, respectively) can be considered as if every responder improved by 21, 29, 31, and 33.5% in the responder's respective treatment group. Pain improvement was significantly better with pregabalin (P < 0.05), with pregabalin responders improving by 8.4% (300 mg/day), 10.7% (450 mg/day), and 12.5% (600 mg/day) more than placebo responders. This novel approach demonstrates that responder profiles can provide an enhanced interpretation of pain outcomes for patient care and symptom management.
Urethral Injury by an Orthopedic Screw: An Unusual Cause of Hematuria

Pelvic fractures are commonly associated with urethral disruption; however, urethral injury from the repair of these fractures is rarely reported. Thus, the management of these injuries has not been well defined. We report a case of urethral injury from orthopedic screw insertion presenting 3 months postoperatively and effectively managed with removal of the screw and temporary Foley catheterization.
Electroless Deposition and Characterization of PtxRu1−x Catalysts on Pt/C Nanoparticles for Methanol Oxidation

The electroless deposition of Pt x Ru 1―x catalysts using hydrazine dihydrochloride or formic acid as the reducing agent in a modified Leaman bath was investigated. The effect of potential on the Pt x Ru 1 ―x composition was investigated by potentiostatically depositing Pt x Ru 1―x thin films on gold from acidic chloride electrolytes at potentials between ―0.46 V and 0.34 V (versus normal hydrogen electrode). The physical characteristics and elemental composition of the deposits were determined. An empirical model for the deposition process was developed, taking into account reactant concentration, temperature, and surface potential. The model accurately characterized the deposit composition over a wide Pt/Ru range. The surface potential was estimated to be 0.15 V during electroless deposition using formic acid as the reducing agent based on the empirical model. Deviations from the model were found when hydrazine was used as the reducing agent due to the formation of solution phase ruthenium complexes with hydrazine.
Gergonne's 1815 paper on the design and analysis of polynomial regression experiments

Abstract Brief mention is made of early work in the design of experiments by Galen, Avicenna, and Laplace, after which a seemingly unknown 1815 paper of Gergonne's on polynomial regression is introduced and discussed, and a translation of the paper presented.
Classroom seating arrangements: Instructional communication theory versus student preferences

A study is reported which investigated student preferences for style of classroom arrangement (traditional straightrow, horseshoe, and modular) and seating preferences within each style. Results indicate that arrangement preferences are influenced by both attractiveness of the course involved and student communication apprehension level. It is concluded that manipulation of either type or amount of communication in a classroom may be more difficult than previously believed and that such manipulations have a high probability of engendering negative affect in students which could hinder learning.
Mechanism of NO decomposition in a solid electrolyte reactor by SEP method

Abstract The mechanism of the NO decomposition in the presence of excess O 2 , H 2 O and CO 2 using a ceria-based oxide ionic conductor with a Pd electrode has been studied by solid electrolyte potentiometry (SEP) method. A single compartment cell for measuring P O 2 , Pt | YSZ | Pt, are attached to another single compartment cell for decomposing NO, Pd | Ce 0.8 Sm 0.2 O 1.9 | Pd, where their working electrodes come into contact with each other. Experiments were carried out with a mixture of 2611 ppm NO, 0.1–4% O 2 , 0–5% H 2 O and 0–5% CO 2 in argon at 800°C. A P O 2 measurement in the neighborhood of the Pd electrode during NO decomposition confirms that the NO decomposition is initiated after the electrochemical oxygen pump is completed. A comparison of the Pd electrodes heated at 850°C with that heated at 1300°C shows that the poorer the oxygen pumping property, the better the NO decomposition. On the basis of these results, the mechanism of the NO decomposition is discussed in detail. In addition, the SEP method also gives information about the influences of the coexistent O 2 , H 2 O and CO 2 on the NO decomposition.
A Sociological Jurisprudence for Parricide

Although rates of violence committed by adults have recently been declining, murder by juveniles has continued a steady increase. Of particular interest are cases of parricide, which are receiving more attention in both the popular media and criminal justice research. As more research emerges addressing parricide, particular implications arise concerning the etiology, prosecution, and treatment of these offenders. Under existing law, only a medical finding of clinical psychosis can be used as a defense for parricide. An alternative explanation understands parricide as a rational response to long-standing abuse. By examining representative case studies, this article finds psychiatric explanations of parricide and self-defense by abused children inadequate explanatory models. A sociological jurisprudence is proposed that considers family disintegration, weakened moral values, drug abuse, and family violence and neglect as salient causes of parricide. Only by considering all the factors that create this offe...
Determination of Reference Chemical Potential Using Molecular Dynamics Simulations

A new method implementing molecular dynamics (MD) simulations for calculating the reference properties of simple gas hydrates has been proposed. The guest molecules affect interaction between adjacent water molecules distorting the hydrate lattice, which requires diverse values of reference properties for different gas hydrates. We performed simulations to validate the experimental data for determining Δ𝜇0𝑤, the chemical potential difference between water and theoretical empty cavity at the reference state, for structure II type gas hydrates. Simulations have also been used to observe the variation of the hydrate unit cell volume with temperature. All simulations were performed using TIP4P water molecules at the reference temperature and pressure conditions. The values were close to the experimental values obtained by the Lee-Holder model, considering lattice distortion.
Humanizing education: Dewey's concepts of a democratic society and purpose in education revisited

Humanizing education in a democratic society requires an adequate conception of democratic life. Dewey's ideal of a society with free interaction among groups and extensive sharing of interests provides such a vision. His idea of purposing, as a key ingredient in meaningful learning, thought and action, also gives depth to the concept of education in democracy.
Effects of Television Advertising on African American Teenagers.

The 1990 census reported that the 31 million African Americans, the largest minority group, accounted for 12.1% of the U.S. population, up from 11.7% a decade earlier ("1990 Census Shows," 1991). African Americans as a group represent a large and growing consumer market. According to a recent consumer survey, African Americans spent more than $170 billion a year. Although many African Americans are poor, two thirds are not (Waldrop, 1990, p. 32). As African Americans become a major economic force, the representation of African Americans in advertisements has been increasing significantly in recent years. Previous research suggested that African Americans in general react favorably to advertisements and products that use African American endorsers. The most widely used celebrity endorsers have been sports figures, actors, or other types of entertainers. However, critics say that using African American models in advertisements for products such as tobacco and alcohol is unethical, particularly when these products are aimed at the African American market. They argue that such a practice only serves to exacerbate health and family problems in the community. Nike advertisements that feature basketball player Michael Jordan and film director Spike Lee have recently been the target of negative press. Critics have noted that shoes have become so important that young urban African Americans are willing to kill for them (Waldrop, 1990). African Americans were estimated to generate one third of
Mapping impedance microstructures in rocks with acoustic microscopy

Various methods can characterize microstructural properties of reservoir rocks with the ultimate goal of relating microstructure to seismic properties. Scanning electron microscopy, transmission electron microscopy, and optical microscopy have traditionally been used for such studies. They have identified lithology, pore space, interconnectivity of pores, grain size, and cementation as the most important factors controlling seismic wave velocity and attenuation. However, these techniques provide qualitative descriptions only. The acoustic techniques presented here, scanning acoustic microscopy (SAM) and acoustic sounding (AS), can map and, more importantly, quantify microstructure as variations in acoustic impedance. Ultrasonic stress waves are sensitive to local variations in elastic properties and are therefore particularly suited for characterizing microstructural properties of reservoir rocks. Reflections from impedance boundaries in grains and between interfaces in the sample are used to construct the microstructural image. This paper will show that acoustic microscopy can be a powerful tool for studying internal structure and pore geometry of reservoir rocks. Acoustic microscopy's basic principle is almost identical to that of reflection seismology. Images of surface and subsurface microstructures are prepared on the basis of reflected acoustic waves—that is, on the impedance changes in the sample. Acoustic waves on a sample are mode converted, partly transmitted into the sample, and partly reflected. The reflection coefficient and with it the signal intensity received by the transducer are determined by the elastic constants of the material. Changes in acoustic impedance in the sample that influence wave reflection characteristics can be studied by mapping the reflected waves. Because the working frequency of the acoustic waves can be varied, their penetration depth into the sample and the resolution of microstructural features can be controlled. I will present results from high-frequency SAM (0.1–2 GHz) and low-frequency AS (25–100 MHz). The resolution of SAM is about 1 μm at 1 GHz; AS …
Evolution of Cardiac Calcium Waves from Stochastic Calcium Sparks

We present a model that provides a unified framework for studying Ca2+ sparks and Ca2+ waves in cardiac cells. The model is novel in combining 1) use of large currents (approximately 20 pA) through the Ca2+ release units (CRUs) of the sarcoplasmic reticulum (SR); 2) stochastic Ca2+ release (or firing) of CRUs; 3) discrete, asymmetric distribution of CRUs along the longitudinal (separation distance of 2 microm) and transverse (separated by 0.4-0.8 microm) directions of the cell; and 4) anisotropic diffusion of Ca2+ and fluorescent indicator to study the evolution of Ca2+ waves from Ca2+ sparks. The model mimics the important features of Ca2+ sparks and Ca2+ waves in terms of the spontaneous spark rate, the Ca2+ wave velocity, and the pattern of wave propagation. Importantly, these features are reproduced when using experimentally measured values for the CRU Ca2+ sensitivity (approximately 15 microM). Stochastic control of CRU firing is important because it imposes constraints on the Ca2+ sensitivity of the CRU. Even with moderate (approximately 5 microM) Ca2+ sensitivity the very high spontaneous spark rate triggers numerous Ca2+ waves. In contrast, a single Ca2+ wave with arbitrarily large velocity can exist in a deterministic model when the CRU Ca2+ sensitivity is sufficiently high. The combination of low CRU Ca2+ sensitivity (approximately 15 microM), high cytosolic Ca2+ buffering capacity, and the spatial separation of CRUs help control the inherent instability of SR Ca2+ release. This allows Ca2+ waves to form and propagate given a sufficiently large initiation region, but prevents a single spark or a small group of sparks from triggering a wave.
Relaxation Dynamics in Rare Earth-Doped GaN

Time-resolved photoluminescence spectroscopy of rare earth (Eu, Er, Tm) -doped GaN revealed that optical properties and relaxation dynamics depend surprisingly upon excitation energy, pulse width, temperature, and dopant site.
Interaction of chemical heating and the diurnal tide in the mesosphere

[1] Much of the solar energy deposited into the upper part of the middle atmosphere is realized as heat as a consequence of exothermic chemical reactions. The heating varies with time primarily in response to variations in composition due to photochemistry and to vertical advection by tides and other processes. Diurnal variations in the heating can, in turn, cause modifications in the tidal amplitude and structure. Using a three-dimensional chemical-dynamical model, we show that the advection of atomic oxygen by tidal winds has a significant impact on the location, timing, and magnitude of the heating but that the feedback of this on the tidal amplitude is weak (less than 10%). The day/night cycle in chemical heating associated with photochemistry also contributes to the local amplification or damping of the tide. Tidal transport affects the overall composition and therefore also the total heating by solar energy. When tides are removed, the total global mean amount of solar heating (chemical heating plus direct solar heating) decreases by as much as 40% in the mesosphere.
Crash states and the equity premium: Solving one puzzle raises another

Abstract This paper examines the behavior of asset returns as predicted by the consumption-based capital asset pricing model within an artificial economy that includes a low probability, crash state in consumption and dividends. It is demonstrated that the behavior of agents' intertemporal marginal rate of substitution in such an economy is consistent with the Hansen and Jagannathan (1991) frontier even though the consumption process in the model is calibrated to actual data, preferences are time separable, and agents' relative risk aversion is restricted to moderate levels. Moreover, as demonstrated by Rietz (1988), the crash-state economy can replicate the mean of excess returns on equity, i.e. the equity premium. However, the model severely underpredicts the volatility of excess returns.
Dendroclimatological analysis of major forest species of the central Appalachians

Abstract A dendroclimatological study was carried out in the 80-year-old Fernow Experimental Forest of the U.S. Forest Service near Parsons, West Virginia (39°20′N, 79°40′W). The relationship between radial and basal area increments and corresponding monthly, seasonal, and yearly mean air temperature and precipitation were obtained over 53 years for four species: black cherry ( Prunus serotina Ehrh.), northern red oak ( Quercus rubra L.), white ash ( Fraxinus americana L.), and yellow poplar ( Liriodendron tulipifera L.). These species show positive growth responses to rainfall of previous summer, autumn, and current summer. They show significantly inverse correlation to air temperature of the current growing season. The indices of radial increment show a close correlation to those of basal area increment. However, in our analyses, basal area increment indices are more sensitive to climatic variations than radial growth indices.
Radiative decay engineering: biophysical and biomedical applications.

Fluorescence spectroscopy is a widely used research tool in biochemistry and molecular biology. Fluorescence has also become the dominant method enabling the revolution in medical diagnostics, DNA sequencing, and genomics. To date all the fluorescence observables, including spectral shifts, anisotropies, quantum yields, and lifetimes, have all been utilized in basic and applied uses of fluorescence. In this forward-looking article we describe a new opportunity in fluorescence, radiative decay engineering (RDE). By RDE we mean modifying the emission of fluorophores or chromophores by increasing or decreasing their radiative decay rates. In most fluorescence experiments the radiative rates are not changed because these rates depend on the extinction coefficient of the fluorophore. This intrinsic rate is not changed by quenching and is only weakly dependent on environmental effects. Spectral changes are usually caused by changes in the nonradiative rates resulting from quenching or resonance energy transfer. These processes affect the emission by providing additional routes for decay of the excited states without emission. In contrast to the relatively constant radiative rates in free solution, it is known that the radiative rates can be modified by placing the fluorophores at suitable distances from metallic surfaces and particles. This Review summarizes results from the physics literature which demonstrate the effects of metallic surfaces, colloids, or islands on increasing or decreasing emissive rates, increasing the quantum yields of low quantum yield chromophores, decreasing the lifetimes, and directing the typically isotropic emission in specific directions. These effects are not due to reflection of the emitted photons, but rather as the result of the fluorophore dipole interacting with free electrons in the metal. These interactions change the intensity and temporal and spatial distribution of the radiation. We describe the unusual effects expected from increases in the radiative rates with reference to intrinsic and extrinsic biochemical fluorophores. For instance, the decreased lifetime can result in an effective increase in photostability. Proximity to nearby metallic surfaces can also increase the local field and modify the rate of excitation. We predict that the appropriate localization of fluorophores near particles can result in usefully high emission from "nonfluorescent" molecules and million-fold increases in the number of photons observable from each fluorophore. We also describe how RDE can be applied to medical testing and biotechnology. As one example we predict that nearby metal surfaces can be used to increase the low intrinsic quantum yields of nucleic acids and make unlabeled DNA detectable using its intrinsic metal-enhanced fluorescence.
Hominoid triosephosphate isomerase: regulation of expression of the proliferation specific isozyme.

Three primary isoforms of the dimeric glycolytic enzyme, triosephosphate isomerase (TPI; EC 5.3.1.1), are detected in proliferating human cells. The electrophoretically separable isoforms result from the three possible combinations of constitutive subunits and subunits expressed only in proliferating cells. Only a single primary isoform is observed in quiescent cells. The two subunits, which differ by covalent modification (s), are products of the single structural locus for this enzyme. Expression of the proliferation specific subunit (TPI-2) is detected within 6–10 hr following mitogen stimulation of quiescent human cells, requires RNA synthesis and is inhibited by agents which inhibit interleukin 2 expression or function. Only the constitutive subunit (TPI-1) is detected in proliferating cells from nonhominoid primate species. A single class of TPI mRNA, which is increased > 10 fold following stimulation of quiescent cells, is detected on northern blot analysis and S1 nuclease digestion analysis of RNA from quiescent and proliferating human cells. It is similar in size to the TPI mRNA from proliferating cells of the African green monkey, a primate species not expressing TPI-2. Comparison of the structure of the TPI gene from rhesus monkey (nonexpressing species) to the gene from expressing species does not suggest a mechanism for generating TPI-2. Thus, the regulation of the expression of the hominoid restricted, proliferation specific subunit of TPI has been further defined, although the mechanism for generating TPI-2 remains elusive.
Reference axes for comparing the motion of knee replacements with the anatomic knee.

Abstract In the literature, different methods have been used to describe the motion of the anatomic knee and total knee replacements (TKR). The major goal of this study was to identify the most suitable methods for comparing TKR motion with that of the anatomic knee, whether for the purpose of developing new TKR designs, or evaluating existing ones. A further goal was to specify a testing methodology which would apply the methodology and represent a wide range of activities. Six knee specimens were tested in a Desktop Knee Machine, where different sequences of compressive, shear, and torque loads were applied at a full range of flexion angles. Data from a typical total knee was obtained by analysis. The motion results were displayed using different reference axes, specifically the circular axis, the epicondylar axis, the line joining the contact points, and the line joining the lowest lateral and medial femoral condylar points. It was concluded that the circular axis was the most generally applicable choice of a key femoral axis, for comparing the rigid body motion of a total knee with anatomic data, but that the actual contact points had important significance in full extension and in high flexion.
Galvanic Corrosion in Metal-Matrix Composites Containing Semiconducting Constituents

A modified photochemical-diode (PD) model, designated as a photochemical-corrosion-diode (PCD) model, was proposed for interpreting galvanic corrosion in metal-matrix composites (MMCs) containing semiconducting constituents. The characteristics of the PCD model were introduced through direct comparison with that of the PD model. The PCD model was then used to interpret galvanic corrosion in SiC-reinforced Al MMCs. The PCD model and the photoelectrochemical experiments on both Al/SiC MMCs and monolithic SiC predicted that solar irradiation may affect the corrosion of the Al/SiC MMCs, corroborating well with field experiments.
A Self-Consistent Multicomponent Activity Coefficient Model for Ionic Micellar Surfactant Solutions

The proposed model incorporates a distribution of micellar sizes self-consistently. The model is based on a mass-action equilibrium approach that includes micelle−micelle interactions as a function...
The tail of a positivity-preserving semigroup

With certain assumptions a representation theorem is proved for the elements of $$ \cap _{\sigma \in \Sigma } $$ σS, where Σ is an abelian semigroup of, endomorphisms of a real vector space, andS is a convex antisymmetric cone. Application is made to chacterization of nonnegative harmonic functions on bounded Lipschitz domains, of Hausdorff-Stieltjes moment sequences, and of “bilateral Laplace transforms” on locally compact abelian groups, Euclidean motion groups, and noncompact semi-simple Lie groups. Uniqueness of the representation is proved in both the Euclidean motion and the semi-simple cases.
The Phenylalanine and Tyrosine Requirements and Their Interrelationship for the Young Chick

Abstract A purified crystalline amino acid diet was used to study the phenylalanine tyrosine interrelationship in young chicks. Dietary phenylalanine and tyrosine requirements for maximal growth were observed to be 0.50±.07% and 0.37±.05%, respectively. Tyrosine was thus capable of furnishing up to 42.5% of the total requirement for aromatic amino acids. Under dietary conditions of phenylalanine adequacy and tyrosine deficiency, phenylalanine was found to be equal in efficacy to tyrosine in providing the limiting nutrient, tyrosine. Efficient molar conversion of phenylalanine to tyrosine was observed.
Geologic constraints on the macroevolutionary history of marine animals

The causes of mass extinctions and the nature of taxonomic radiations are central questions in paleobiology. Several episodes of taxonomic turnover in the fossil record, particularly the major mass extinctions, are generally thought to transcend known biases in the geologic record and are widely interpreted as distinct macroevolutionary phenomena that require unique forcing mechanisms. Here, by using a previously undescribed compilation of the durations of sedimentary rock sequences, I compare the rates of expansion and truncation of preserved marine sedimentary basins to rates of origination and extinction among Phanerozoic marine animal genera. Many features of the highly variable record of taxonomic first and last occurrences in the marine animal fossil record, including the major mass extinctions, the frequency distribution of genus longevities, and short- and long-term patterns of genus diversity, can be predicted on the basis of the temporal continuity and quantity of preserved sedimentary rock. Although these results suggest that geologically mediated sampling biases have distorted macroevolutionary patterns in the fossil record, preservation biases alone cannot easily explain the extent to which the sedimentary record duplicates paleobiological patterns. Instead, these results suggest that the processes responsible for producing variability in the sedimentary rock record, such as plate tectonics and sea-level change, may have been dominant and consistent macroevolutionary forces throughout the Phanerozoic.
The Role of Nitric Oxide in the Regulation of Cellular Iron Metabolism

Eukaryotic cellular iron homeostasis becomes impaired during inflammation, manifesting itself most dramatically as the anemia of chronic disease. This alteration in cellular iron metabolism is the result of a complex network of events, acting at the transciptional and translational levels to alter the expression of proteins involved in the uptake, storage, and utilization of iron. With the discovery of nitric oxide (NO), its role in host defense, and its interactions with a number of different iron-containing proteins, investigators have begun unravelling the connection between iron metabolism and NO. Following a brief discussion of normal cellular iron metabolism, this review focuses on alterations in iron homeostasis observed during inflammation with an emphasis on the role of NO. A working model involving NO in the pathogenesis of the anemia of chronic disease is proposed.
Antagonist activity of phosphorus-containing glutamate analogues in the perforant path.

Abstract Two analogues of the amino acid l -2-amino-4-phosphonobutanoic acid ( l -APB) were synthesized in order to test the hypothesis that the dianionic nature of the side chain is responsible for antagonism of excitatory synapses in the hippocampal perforant path. These compounds, dl -2-amino-4-(methylphosphino)-butanoic acid ( dl -AMPB) and O-methylphosphonyl- l -serine (O-MPLS), possess singly-charged side chains and yet display antagonistic activity, illustrating that a dianionic charge on the side chain is not necessary for antagonism. Comparing structure-activity relationships for dl -AMPB, O-MPLS, l -APB, and O-phospho- l -serine (O-PLS), patterns of synaptic activity emerged which suggest that substitution of a methyl group for one of the phosphoryl hydroxyl groups lowers ligand potency in both medial and lateral pathways. Also, the nature of the atom at the γ-position appears to alter the potency and degree of pathway selectivity of these ligands, a methylene unit imparting more potency and selectivity than an oxygen atom.
Saline is our friend.

Irrigating fluid is used in urologic endoscopy to dilate the target organ and clear the visual field of debris and blood. The introduction of nonphysiologic fluid can offer limited advantages, but it also severely increases the risks. Hypotonic liquid (eg, water) improves visibility by lysing red blood cells and can be used for electrosurgery. However, it can result in disastrous consequences if it enters the blood stream. Our independent experience in reviewing nonreported legal cases stemming from the use of water as an endourologic irrigant has emphasized the importance of the choice of irrigating fluid and the associated risks. The absorption of large amounts of hypotonic irrigant during transurethral resection of the prostate (TURP) leads to a spectrum of cardiovascular and neurologic derangements collectively known as the transurethral resection (TUR) syndrome. Before the introduction of nonhemolytic irrigating fluid, the TUR syndrome accounted for most of the morbidity and mortality associated with TURP. Arguably, the single greatest advancement in TURP was the recognition of Creevy 1 that irrigation with distilled water was the cause of hemolysis and shock after intravascular absorption. In 3500 patients, Creevy showed that the use of glycine for irrigation during TURP reduced perioperative mortality from 4% to 0.85%. 2,3 This significant reduction in morbidity and mortality with the use of nonhemolytic irrigating solutions was firmly validated 13 years later by an analysis of 20,000 TURPs at the Mayo Clinic. 4 The recent
Hyperoxia alters platelet disposition of serotonin.

Abstract Exposure of mice to normobaric 100% oxygen for 24–96 h is known to damage the pulmonary capillary endothelium and alter the disposition of serotonin (5-hydroxytryptamine, 5-HT). We now report that such exposure increased the concentration of platelets and decreased the platelet content of 5-HT and a tracer dose of [3H]5-HT. After 48 h of hyperoxia exposure, the platelet concentration was elevated to 121% of air-exposed control values and the content of 5-HT and [3H]5-HT/109 platelets was decreased 76% and 57%, respectively. Kinetic analysis of the platelet 5-HT uptake process indicated that hyperoxia exposure caused an increased affinity and decreased velocity of transport. After 48 h of oxygen exposure the Km for platelet 5-HT uptake was 1.91 ± 0.67 · 10−7 M and the Vmax 30.1 ± 4.6 pmol/108 platelets/4 min compared to air-exposed control values of Km 3.37 ± 0.32 · 10−7 M and Vmax 46.7 ± 3.5 pmol/108 platelets/4 min, respectively. These changes in platelet 5-HT uptake and disposition may contribute to the pathophysiology of the pulmonary microvascular response to hyperoxia-induced injury.
Firefly Luciferase Is Targeted to Peroxisomes in Mammalian Cells

Abstract Although several enzymes known to reside in peroxisomes have been studied extensively, no cis-acting amino acid sequences involved in the transport of these proteins to peroxisomes have been described. As a first step towards the determination of a putative peroxisomal targeting sequence, we have expressed the cDNA encoding the firefly luciferase [Photinus-luciferin:oxygen 4-oxidoreductase (decarboxylating, ATP-hydrolyzing), EC 1.13.12.7] in monkey kidney cells and found that the product of the gene is transported to peroxisomes. Luciferase is derived from the firefly (Photinus pyralis) and is synthesized and stored in the cells of the firefly's lantern organ, where it is also found in peroxisomes. The fact that this protein is similarly targeted in cells from such different organisms suggests that the process of protein transport to peroxisomes has been highly conserved through evolution.
An examination of DBMS adoption and success in American organizations

Abstract Database technology has been available for over two and a half decades and yet widespread adoption has not occured. This study examines a relatively mature IS technology in an attempt to understand factors that facilitate its adoption. Specifically, the maturity of the IS function and demographic characteristics are proposed as factors distinguishing adopters from non-adopters. The results of a survey of 288 American organizations are reported. The results indicate that the adoption of DBMS is consistent with several indicators of IS maturity, size, and industry. Additional results reveal that suggested database benefits are not being achieved by these organizations.
Properties of IR absorption spectra of Bi-Pb-Sr-Ca-Cu-O superconducting material

Abstract We used the co-decomposition method to make the Bi(Pb)-Sr-Ca-Cu-O superconductor samples (Tc = 112K) under oxygen partial pressure. Oxygen dependence of high-Tc phase was studied. The infrared absorption spectra of (Bi1−xPbx)2Sr2Ca2Cu3O10+σ superconductor were measured at various temperatures from 98 to 290K. A new IR absorption peak was observed at 1265 cm−1 below 217K. The intensity of this peak became stronger with temperature decreasing.
Design and operation of the U.C.L.A. 50 MeV spiral-ridge cyclotron†

The design and operation of the U.C.L.A. 50 Mev cyclotron is described. The magnetic field is presented in a series of graphs and orbit calculations on beam stability are given. The results of experimental observations and measurements on the internal beam include beam intensity graphs and photographs, piots of / nu /sub z/ and nu /sub r/ from r.f. knockout measurements, beam intensity as a function of dee voltage, and radial oscillation amplitude of the beam. Because of iack of shielding, the beam has been restricted to 2 mu a of 50 Mev protons by use of a 5% duty cycle. An increased intensity is expected when a puller electrode is used at the source. The tuning up of the beam by means of the eight circular coils for trimming the magnetic field has been found to be quite simple in practice. Efforts to get an external beam are now proceeding in the permanent shielding vault. (auth)
Theoretical and Experimental Investigation of the Effect of Proton Transfer on the 27Al MAS NMR Line Shapes of Zeolite−Adsorbate Complexes: An Independent Measure of Solid Acid Strength

Assessing the degree of proton transfer from a Bronsted acid site to one or more adsorbed bases is central to arguments regarding the strength of zeolites and other solid acids. In this regard certain solid-state NMR measurements have been fruitful; for example, some 13C, 15N, or 31P resonances of adsorbed bases are sensitive to protonation, and the 1H chemical shift of the Bronsted site itself reflects hydrogen bonding. We modeled theoretically the structures of adsorption complexes of several bases on zeolite HZSM-5, calculated the quadrupole coupling constants (Qcc) and asymmetry parameters (η) for aluminum in these complexes and then in turn simulated the central transitions of their 27Al MAS NMR spectra. The theoretical line width decreased monotonically with the degree of proton transfer, reflecting structural relaxation around aluminum as the proton was transferred to a base. We verified this experimentally for a series of adsorbed bases by way of single-pulse MAS and triple quantum MQMAS 27Al NMR....
Combinatorial study of thin-film Cu 2 ZnSnS 4 synthesis via metal precursor sulfurization

We report on studies related to the synthesis of thin-film Cu 2 ZnSnS 4 via sulfurization of metal-precursor thin films. Combinatorially graded thin-film Cu-Zn-Sn library samples spanning various regions of the ternary Cu-Zn-Sn phase diagram were deposited at temperatures below 375 K and subsequently sulfurized in a high-vacuum system equipped with a sulfur valved-cracking source at temperatures from 600 K to 675 K. Comparisons of x-ray fluorescence and x-ray diffraction data from pre- and post-sulfurization films have revealed correlations between processing conditions, film composition, and the crystalline phases present. We have also performed cathodoluminescence and photoluminescence measurements and identified emission features consistent with the formation of the Cu 2 ZnSnS 4 .
Chemometric study of the influence of instrumental parameters on ESI-MS analyte response using full factorial design

Abstract Full factorial experimental design technique was used to study the main effects and the interaction effects between instrumental parameters in two mass spectrometers equipped with conventional electrospray ion sources (Thermo LCQ Deca XP and Shimadzu LCMS 2010). Four major parameters (spray voltage, ion transfer capillary temperature, ion transfer capillary voltage, and tube lens voltage) were investigated in both instruments for their contribution to analyte response, leading to a total of 16 experiments performed for each instrument. Significant parameters were identified by plotting the cumulative probability of each treatment against the estimated effects in normal plots. Analysis of variance (ANOVA) was employed to evaluate the statistical significance of the effects of the parameters on ESI-MS analyte response. The results reveal a number of important interactions in addition to the main effects for each instrument. In all the experiments performed, the tube lens voltage (or Q-array dc voltage in LCMS 2010) was found to have significant effects on analyte response in both instruments. The tube lens voltage was also found to interact with the capillary temperature in the case of the LCQ Deca XP and with the spray voltage in the case of the LCMS 2010. The results of these experiments provide important considerations in the instrumental optimization of ionization response for ESI-MS analysis.
Interpreting temperature-strain data from mesoscale clathrate experiments

Gas hydrates may play an important role in global climate change, carbon sequestration, energy production and seafloor stability. However, formation and dissociation pathways in geologically complex systems are poorly defined. We present a new approach to processing large amounts of data from a LUNA distributed sensing system (DSS) in the seafloor process simulator (SPS) at Oak Ridge National Laboratory to monitor and visualize gas hydrate formation and dissociation in heterogeneous sediments. The DSS measures relative temperature/strain change with a high spatial resolution allowing the heat of reaction during gas hydrate formation/dissociation to be used to locate clathrate processes in space and time within the vessel. Optical fibers are placed in the sediment following an Archimedean spiral design and the position of each sensor is determined iteratively over the arc length using Newton's method. The DSS data are then gridded with a natural neighbor interpolation algorithm to allow contouring. The locations of sensors on the fiber were verified with hot and cold stimuli in known locations. Software was developed to produce temperature/strain linear and polar plots, which aid in locating significant hydrate formation/dissociation events. Results from an experiment using a vertically split column of sand and silt clearly showed initial hydrate formation in the sand, followed by slow encroachment into the silt. Similar systems and data processing techniques could be used for monitoring of hydrates in natural environments or in any situation where a hybrid temperature/strain index is useful.