cssi/SciSciGPT-SciSciNet huggingface dataset:
Single-level subject-specific finite element model can predict fracture outcomes in three-level spine segments under different loading rates

Abstract Osteoporosis-related vertebral compression fracture can occur under normal physiological activities. Bone metastasis is another source of vertebral fracture. Different loading rates, either high-energy traumas such as falls or low-energy traumas under normal physiological activities, can result in different fracture outcomes. The aim of the current study was to develop a quantitative computed tomography-based finite element analysis (QCT/FEA) technique for single vertebral bodies to predict fracture strength of three-level spine segments. Developed QCT/FEA technique was also used to characterize vertebral elastic moduli at two loading rates of 5 mm/min, representing a physiologic loading condition, and 12000 mm/min, representing a high-energy trauma. To this end, a cohort of human spine segments divided into three groups of intact, defect, and augmented were mechanically tested to fracture; then, experimental stiffness and fracture strength values were measured. Outcomes of this study showed no significant difference between the elastic modulus equations at the two testing speeds. Areal bone mineral density measured by dual x-ray absorptiometry (DXA/BMD) explained only 53% variability (R2 = 0.53) in fracture strength outcomes. However, QCT/FEA could explain 70% of the variability (R2 = 0.70) in experimentally measured fracture strength values. Adding disk degeneration grading, testing speed, and sex to QCT/FEA-estimated fracture strength values further increased the performance of our statistical model by 14% (adjusted R2 of 0.84 between the prediction and experimental fracture forces). In summary, our results indicated that a single-vertebra model, which is computationally less expensive and more time efficient, is capable of estimating fracture outcomes with acceptable performance (range: 70–84%).
Lower limb kinematics of male and female soccer players during a self-selected cutting maneuver: Effects of prolonged activity

Abstract Background Despite the recent emphasis on injury prevention, anterior cruciate ligament (ACL) injury rates remain high. This study aimed to ascertain the effects of prolonged activity on lower limb kinematics during a self-selected cutting maneuver. Methods Angular kinematics were recorded during an agility test performed until the completion time was greater than the mean plus one SD of baseline trials. Cut type was identified and the hip and knee angles at 33 ms post heel strike were determined. A linear mixed effects model assessed the effects of cut type, gender, and activity status on the hip and knee angles. Results Males performed sidestep cuts more frequently than females. Females increased the incidence of sidestep cuts after prolonged activity. At the hip, a gender–cut type interaction existed for the transverse (p = 0.001) and sagittal (p = 0.11) planes. Females showed more internal rotation during sidestep and more external rotation and less flexion during crossover cuts. For the frontal plane, a gender–activity status interaction (p = 0.032) was due to no change within females but greater hip adduction during prolonged activity within males. With prolonged activity, both genders displayed less hip (p = 0.29) and knee (p = 0.009) flexion and more knee (p = 0.001) adduction. Females displayed less hip and knee flexion than men (p = 0.001). Conclusions Sidestep may be more risky than crossover cuts. Both genders place themselves in at-risk postures with prolonged activity due to less hip and knee flexion. Level of evidence Level 4
Amyloid-β Metal Interaction and Metal Chelation

Alzheimer’s disease (AD) is associated with the abnormal aggregation of amyloid-beta (Aβ) protein. Aβ and its precursor protein (APP) interact with metal ions such as zinc, copper and iron. Evidence shows that these metals play a role in the precipitation and cytotoxicity of Aβ. Despite recent advances in AD research, there is a lack of therapeutic agents to hinder the apparent aggregation and toxicity of Aβ. Recent studies show that drugs with metal chelating properties could produce a significant reversal of amyloid-β plaque deposition in vitro and in vivo. Here we discuss the interaction of Aβ with metals, metal dyshomeostasis in the CNS of patients with AD, and the potential therapeutic effects of metal chelators.
Desmosomal defects in acantholytic squamous cell carcinomas

Background Acantholytic squamous cell carcinoma (Acantholytic SCC) are epithelial tumors characterized by a loss of cell adhesion between neoplastic keratinocytes. The mechanism underlying loss of cell-cell adhesion in these tumors is not understood. Methods A retrospective analysis of acantholytic SCC (n = 17) and conventional SCC (n = 16, controls not showing acantholysis) was conducted using a set of desmosomal and adherens junction protein antibodies. Immunofluorescence microscopy was used to identify tumors with loss of adhesion protein expression. Results The vast majority of acantholytic SCC (89%) showed focal loss of at least one desmosomal cell adhesion protein. Most interestingly, 65% of these tumors lost expression of two or more desmosomal proteins. Conclusions Loss of cell adhesion in acantholytic SCC is most likely linked to the focal loss of desmosomal protein expression, thus providing potential mechanistic insight into the patho-mechanism underlying this malignancy.
Gene Expression in the Brain across the Hibernation Cycle

The purpose of this study was to characterize changes in gene expression in the brain of a seasonal hibernator, the golden-mantled ground squirrel, Spermophilus lateralis, during the hibernation season. Very little information is available on molecular changes that correlate with hibernation state, and what has been done focused mainly on seasonal changes in peripheral tissues. We produced over 4000 reverse transcription-PCR products from euthermic and hibernating brain and compared them using differential display. Twenty-nine of the most promising were examined by Northern analysis. Although some small differences were observed across hibernation states, none of the 29 had significant changes. However, a more direct approach, investigating expression of putative hibernation-responsive genes by Northern analysis, revealed an increase in expression of transcription factors c-fos, junB, and c-Jun, but not junD, commencing during late torpor and peaking during the arousal phase of individual hibernation bouts. In contrast, prostaglandin D2 synthase declined during late torpor and arousal but returned to a high level on return to euthermia. Other genes that have putative roles in mammalian sleep or specific brain functions, including somatostatin, enkephalin, growth-associated protein 43, glutamate acid decarboxylases 65/67, histidine decarboxylase, and a sleep-related transcript SD464 did not change significantly during individual hibernation bouts. We also observed no decline in total RNA or total mRNA during torpor; such a decline had been previously hypothesized. Therefore, it appears that the dramatic changes in body temperature and other physiological variables that accompany hibernation involve only modest reprogramming of gene expression or steady-state mRNA levels.
First results with high-resolution PET detector modules using wavelength-shifting fibers

The authors have constructed and tested prototype PET detector modules incorporating wavelength-shifting fiber ribbons alternating with thin CsI(Na) scintillator plates in multilayer stacks. Modules with cross-sectional area of 11 cm/spl times/11 cm and with 9 mm of total crystal thickness have been tested. A reconstructed spatial resolution of 3 mm FWHM has been obtained for a line source, with an energy resolution of <20% and a time resolution of 25 ns FWHM. Energy measurements and coincidence timing are provided by 4 photomultipliers in an Anger array on one 11 cm/spl times/11 cm module face. Multiplexed fiber readout has been implemented with multianode photomultipliers coupled to several fiber ribbons. The methods and resolution achieved are readily extended to larger systems in a straightforward and cost-effective manner. Results of tests with several phantoms are presented.
Antioxidative responses to arsenic in the arsenic-hyperaccumulator Chinese brake fern (Pteris vittata L.).

This study measured antioxidative responses of Chinese brake fern (Pteris vittata L.) upon exposure to arsenic (As) of different concentrations. Chinese brake fern was grown in an artificially-contaminated soil containing 0 to 200 mg As kg(-1) (Na2HAsO4) for 12 weeks in a greenhouse. Soil As concentrations at 20 mg As kg(-1). Plant As concentrations increased with soil As concentrations, with more As being accumulated in the fronds (aboveground biomass) than in the roots and with maximum frond As concentration being 4675 mg kg(-1). Arsenic uptake by Chinese brake enhanced uptake of nutrient elements K, P, Fe, Mn, and Zn except Ca and Mg, whose concentrations mostly decreased. The contents of non-enzymatic antioxidants (glutathione, acid-soluble thiol) followed similar trends as plant As concentrations, increasing with soil As concentrations, with greater contents in the fronds than in the roots especially when exposed to high As concentrations (>50 mg kg(-1)). The activities of enzymatic antioxidants (superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase) in Chinese brake followed the same trends as plant biomass, increasing with soil As up to 20 mg kg(-1) and then decreased. The results indicated though both enzymatic and non-enzymatic antioxidants played significant roles in As detoxification and hyperaccumulation in Chinese brake, the former is more important at low As exposure (< or =20 mg kg(-1)), whereas the latter is more critical at high As exposure (50-200 mg kg(-1)).
A Simulation Approach to Understand the Viability of RFID Technology in Reducing Medication Dispensing Errors

RFID technology has the potential to reduce medication dispensing errors in hospitals. To determine possible uses for tracking medication within a hospital, we interviewed a pharmacist with knowledge of such processes. Due to cost considerations, the most viable place to use RFID technology is to track medication upon leaving the pharmacy, which can help reduce lost or misplaced medication and ensure that the right medication is given to the right patient. A simulation model that compares the benefits with and without RFID is also discussed.
Water isotopologues as a quantitative paleosalinity proxy

[1] Paleosalinity reconstructions are a goal of paleoceanographic study because of their potential to provide insight into past ocean circulation. While temperature reconstructions have been assessed by using multiple independent proxies, the skill of existing salinity reconstructions remains poorly quantified. We examine the applicability of two different approaches using a set of coupled water isotope–enabled general circulation model experiments as a numerical analog for the real climate system. These simulations for the Holocene, at roughly 1000 year time steps, explicitly track variability in both the water isotopologues and salinity. Our simulations suggest that quantitative reconstructions of past salinity variability based solely on inferred δ18Osw variability have very large errors and uncertainties. However, we find that paired δ18Osw and δD variability (from combining biomarker and calcite proxies) holds promise for providing better quantitative estimates of salinity variability.
Chemoprevention in gastrointestinal physiology and disease. Anti-inflammatory approaches for colorectal cancer chemoprevention

Colorectal cancer (CRC) is one of the most common human malignancies and a leading cause of cancer-related deaths in developed countries. Identifying effective preventive strategies aimed at inhibiting the development and progression of CRC is critical for reducing the incidence and mortality of this malignancy. The prevention of carcinogenesis by anti-inflammatory agents including nonsteroidal anti-inflammatory drugs (NSAIDs), selective cyclooxygenase-2 (COX-2) inhibitors, and natural products is an area of considerable interest and research. Numerous anti-inflammatory agents have been identified as potential CRC chemopreventive agents but vary in their mechanism of action. This review will discuss the molecular mechanisms being studied for the CRC chemopreventive activity of NSAIDs (i.e., aspirin, sulindac, and ibuprofen), COX-2 inhibitors (i.e., celecoxib), natural products (i.e., curcumin, resveratrol, EGCG, genistein, and baicalein), and metformin. A deeper understanding of how these anti-inflammatory agents inhibit CRC will provide insight into the development of potentially safer and more effective chemopreventive drugs.
Differential activities of putative subsarcolemmal and interfibrillar mitochondria from cardiac muscle

Mitochondria were isolated from rat hearts by Polytron treatment in a low ionic strength medium. The mitochondria that remained in the tissue after Polytron treatment were then isolated by Nagarse treatment in a high ionic strength medium. Properties of these two preparations were compared. The state 3 rate of respiration was not significantly different between Polytron and Nagarse prepared mitochondria if the assay was carried out in a low ionic strength sucrose medium. On the other hand, when the assay was carried out in a high ionic strength KCl medium, a significant difference in state 3 rate was observed between these two preparations of mitochondria, mainly due to the decreased state 3 rate of Polytron mitochondria. The total cytochrome c and a + a3 content and enzyme activities were similar in Polytron and Nagarse mitochondria. Although no release of cytochrome c was observed in low ionic strength assay medium, about 25% of the total cytochrome c was released from Polytron mitochondria in the high ionic strength assay medium. It was, therefore, concluded that the difference in state 3 rate of respiration in KCl assay medium is probably due to the loss of cytochrome c into the medium and may not represent any physiological difference between them.
Postoperative lower extremity bypass surveillance: Beyond ankle arm blood pressures

Surveillance is essential to the postoperative follow-up of lowerextremity bypass grafts. Early, intermediate, and late thrombosis place the patient's limb at risk, so detection of problems before the graft fails is critical. Because contrast angiography is not routinely performed for surveillance, most vascular surgeons rely on history, physical examination, and noninvasive vascular studies (NVS) to assess perfusion to the lower extremity after bypass grafting. These NVS include ankle/brachial waveforms, blood pressures, and indexes before and after exercise. The purpose of this study is to report our findings with duplex color-flow ultrasonography (DCU) to examine lower extremity bypass grafts. According to our protocol, we monitor lower extremity grafts with ankle/brachial Doppler pressures, analogue waveforms, and lower extremity exercise when possible. These NVS are performed by nurses in the vascular laboratory before the patient is discharged from the hospital, at least twice during the first year, and then annually. DCU is also performed at least two times during the first year and then annually. If the study results are abnormal or if the patient has symptoms, testing is usually repeated. When abnormalities persist contrast angiography may be warranted. We have detected anatomic and hemodynamic changes in lower extremity bypasses by use of our protocol. By adding DCU to ankle/brachial blood pressures, we have identified aneurysmal dilation, diffuse atherosclerosis, focal narrowing, arteriovenous fistulas caused by unligated venous branches, retained venous valves, and disease progression proximal or distal to the graft. For years nurses in the vascular laboratory have been able to assess the hemodynamics of lower extremity bypass grafts by use of history, physical examination, ankle and arm blood pressures, and waveforms. Now with DCU the vascular laboratory progresses beyond these methods to detect abnormalities in graft anatomy early, before the graft fails. Consequently tissue damage and limb loss of patients can potentially be minimized.
Reduced parasitism of a leaf-mining moth on trees with high infection frequencies of an endophytic fungus

We investigated relationships between endophytic fungi and a leaf-mining moth, Phyllonorycter sp., along an elevational gradient from 2255 to 2895 m. The fungi and moth larvae inhabit leaves of Quercus gambelii. Fungal frequencies and larval densities varied with elevation. However, larval densities were not associated with the frequencies of infection by endophytic fungi. Survival of larvae was positively associated with the most dominant fungus, Gnomonia cerastis, owing to reduced parasitism of moth larvae on trees with high frequencies of Gnomonia.
Optimal resolutions for optical and NIR spectroscopy

We study the effects of atmospheric emission lines in the night sky on spectroscopic measurements in the 0.4-2.4 μm range at resolutions 100≤R≤50000 to determine an optimal observing resolution. We build a model of the background sky spectrum at various moon phases and calculate the fraction of pixels free of emission lines in 7 different band passes while varying the resolution. We then discuss the effect of the background emission on the signal-to-noise of constant flux targets to determine an optimal resolution at which to observe. Preliminary results show that the emission lines have little to no effect on the selection of resolution in the optical, but that in the wavelengths ranging from 1.0-2.4 μm the effects of atmospheric emission line suggests observing at a resolution of R>2000 is recommended.
Direct, Maskless Fabrication Of Submicrometer Gratings On Semiconductors

Ultrahigh-resolution gratings are produced in GaAs crystals by using two interfering beams to initiate localized chemical reactions at the solid/liquid interface. Optical gratings with periods between 0.1 and 1 }im are produced with controllable and reproducible optical properties. This maskless technique has potential applications in the fabrication of distributed feedback lasers. Futhermore, a variety of groove profiles are made under different etching conditions. A novel aspect of the direct processing is that the grating growth can be monitored in real time by observing the diffraction of the writing beams, thus allowing a precise control over the grating depth and groove profiles. In addition, because the gratings have a very high resolution, the process of grating fabrication becomes a method of studying the micrometer-scale physical processes which influence the grating structure and growth.© (1986) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Observations on the Coalescence Behavior of Oil Droplets and Emulsion Stability in Enhanced Oil Recovery

Results of experiments on the stability of crude oil drops at an oil-water interface and interdroplet coalescence in crude oil-water emulsions containing petroleum sulfonates as surfactant systems, cosurfactants, and other chemical additives have been analyzed in terms of interfacial viscosity, interfacial tension, interfacial charge, and thickness of the films surrounding the microdroplets. A qualitative correlation has been found between coalesence rates and interfacial viscosities; however, there appears to be no direct correlation with interfacial tension. New insight has been gained into the influence of emulsion stability in tertiary oil recovery by surfactant/polymer flooding in laboratory core tests. It is concluded that those systems which result in relatively stable emulsions yield poor coalescence rates and, hence, poor oil recovery. (24 refs.)
Mutagenicity of Pyrolyzates of Natural Substances toward Salmonella typhimurium TA97

(1985). Mutagenicity of Pyrolyzates of Natural Substances toward Salmonella typhimurium TA97. Agricultural and Biological Chemistry: Vol. 49, No. 6, pp. 1893-1895.
Performance of Gauss implicit Runge-Kutta methods on separable Hamiltonian systems

Abstract We consider implementations of a variable step size (and, separately, constant step size), fourth-order symplectic Gauss implict Runge-Kutta method for the solution of Hamiltonian systems. We test our implementations on Kepler's problem with the aim of judging the algorithms' qualitative behavior and efficiency. In particular, we introduce compensated summation as a method of controlling roundoff accumulation. Also, we show how the variable step size Gauss implicit Runge-Kutta method performs on Kepler's problem with solution orbits of high eccentricity, and compare its performance with that of two Runge-Kutta-Nystrom codes. Finally, we discuss the calculation of efficient starting values for the associated iterations, measure the cost in iterations of our various predictors, and comment on the strategies for terminating the iteration.
Crafting a Better Life

This is a review of “The Craftsman” by Richard Sennett, published by Yale University Press, 2008.
Two strategies in fricative discrimination.

Synthetic noises from a [∫]-[s] continuum, followed by vocalic portions that influenced the location of the [∫]-[s] boundary in an identification test, were presented in AXB and fixed-standard AX discrimination tasks. The majority of naive subjects perceived these fricative-vowel syllables fairly categorically in both tasks; that is, discrimination functions followed the patterns predicted from identification scores and showed shifts contingent on the nature of the vocalic portion. However, two subjects achieved much better discrimination scores than the rest, and so did three experienced listeners and a group of less experienced subjects who had received some discrimination training in the AX task. These listeners, who (judging from their higher accuracy, pattern of responses, and subjective reports) successfully followed the nonphonetic strategy of restricting attention to the spectral properties of the fricative noise, were not influenced by different vocalic contexts. These results support the hypothesis that influences of vocalic context on fricative identification are tied to a phonetic mode of perception.
The correlates of planning in adolescent suicide attempts

Adolescent suicide attempts are often impulsive. It has been suggested that individuals who make nonimpulsive (premeditated) attempts have greater suicidal intent and are more hopeless than the impulsive attempters. Eighty-six adolescent suicide attempters were categorized according to the degree of premeditation of their attempt, as measured by two items of the Suicide Intent Scale. Sex, age, method of attempt, and the number of prior attempts were not useful discriminators between these groups. The nonimpulsive attempters were significantly more depressed and more hopeless than the impulsive attempters, as measured by several standardized scales. Measures of depression, hopelessness, and suicidal ideation were highly correlated in both groups. Anger turned inward and hopelessness were strongly correlated only in the premeditated group, suggesting that the nonimpulsive attempter's distress may bear a strong relationship to self anger.
Giants In Orthopaedic Surgery: Sterling Bunnell MD

Note from the Editor-in-Chief: In “Giants In Orthopaedic Surgery,” a columnist explores the life and achievements of an orthopaedic surgeon who changed our profession, by interviewing other surgeons whose lives the “Giant” touched through mentorship or collaboration, or by using other historical sources that provide similar insight. We welcome reader feedback on all of our columns and articles; please send your comments to eic@clinorthop.org. The author certifies that he, or a member of his immediate family, has no funding or commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research ® editors and board members are on file with the publication and can be viewed on request. The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR ® or the Association of Bone and Joint Surgeons®.
Of yeast, mice, and men. Rab proteins and organelle transport.

A typical eukaryotic cell contains many types of membrane organelles with characteristic distributions within the cytoplasm. This distribution is facilitated in part by the organelle binding to a specific subset of motor proteins. Bound motors then transport the organelles to their proper
Sensory gating deficits in schizophrenia: can we parse the effects of medication, nicotine use, and changes in clinical status?☆

Abstract Schizophrenia is a disorder characterized by core deficits in information processing and attentional mechanisms. Abnormalities in the neural substrates associated with the filtering or ‘gating’ of sensory information are among the most consistent findings in schizophrenia research. Intact gating and inhibitory mechanisms are necessary in order to navigate successfully in a stimulus-laden world, and to selectively attend to salient stimuli and ignore redundant, repetitive, or trivial information. An individual's gating functioning can be assessed via self-report measures and/or using laboratory-based psychophysiological paradigms such as P50 event-related potential suppression and prepulse inhibition (PPI). In this paper, the literature on gating deficits across the schizophrenia spectrum and the reported effects of nicotine and medications on P50 suppression and PPI is reviewed. In addition, productive strategies for ‘parsing’ specific medication effects on P50 suppression and PPI deficits and directions for future research that would enable us to answer residual questions about the functional correlates of these abnormalities in schizophrenia patients are discussed.
Toward housing market dynamic analysis

A dynamic model of the housing market is described. A prototype version is used to examine the time paths of market adjustment in response to the implementation of a housing allowance program.
Comparison of the nucleotide sequence and development of a PCR test for the epsilon toxin gene of Clostridium perfringens type B and type D.

The sequence of the epsilon toxin gene of Clostridium perfringens type D was determined and compared with that of the previously reported type B sequence. It showed two nucleotide changes in the open reading frame, giving rise to one amino acid substitution. The promoter sequences were not homologous, and different putative −35 and −10 regions have been identified in each. The sequence information was used to develop PCR primers which were specific for the epsilon toxin gene. The utility of this system for identifying type B or D strains of C. perfringens was demonstrated.
Approximate shift-invariance by warping shift-variant systems

A method is presented in which an image, degraded by a linear shift- variant imaging system, will undergo a warping such that the resulting warped image will be approximately described by a warped original image filtered by a linear shift-invariant system. The purpose of this distortion is to make the shift-variant impulse response, which can approximately be viewed as a shift-invariant impulse response which has been warped in the original image domain, vary as little as possible. In particular cases, a transformation can be found which results in no impulse response variations. For most cases, however, the impulse response will still possess some shift-variance. A measure of shift-variance is presented, and introduced into a optimization problem which seeks to minimize the shift-variance of a system. This residual variance will be ignored (this error must be small in order for this method to work well), and an 'average' impulse response in the warped domain will be assumed. This allows for shift- invariant restoration of the warped image, with all of its attendant advantage is speed and reduced complexity. An example of a smooth space-variant one-dimensional impulse response is applied to a variant of this optimization problem. The limitations of this slightly different problem are explained, and the expected properties of the stated problem are discussed.
Translational control in positive strand RNA plant viruses

The great variety of genome organizations means that most plant positive strand viral RNAs differ from the standard 5′-cap/3′-poly(A) structure of eukaryotic mRNAs. The cap and poly(A) tail recruit initiation factors that support the formation of a closed loop mRNA conformation, the state in which translation initiation is most efficient. We review the diverse array of cis-acting sequences present in viral mRNAs that compensate for the absence of a cap, poly(A) tail, or both. We also discuss the cis-acting sequences that control translation strategies that both amplify the coding potential of a genome and regulate the accumulations of viral gene products. Such strategies include leaky scanning initiation of translation of overlapping open reading frames, stop codon readthrough, and ribosomal frameshifting. Finally, future directions for research on the translation of plant positive strand viruses are discussed.
Deletion of Cyp6d4 does not alter toxicity of insecticides to Drosophila melanogaster

Cytochrome P450-dependent monooxygenases are important in the activation and detoxification of numerous insecticides. In this study, a Drosophila melanogaster Cyp6d4 null mutant was used to determine the role of this P450 in insecticide metabolism. This null mutant was generated by imprecise excision of a mobile P element located upstream to the P450 gene Cyp6d4. Comparative analysis between the non-functional mutant and relevant control strains shows that Cyp6d4 does not appear to be involved in the metabolism of chlorfenapyr, cypermethrin, diazinon, imidacloprid, malathion, oxamyl, parathion, or pyrethrum extract, even though these insecticides are known to be activated or detoxified by P450-monooxygenases. No obvious abnormalities in development were seen in the Cyp6d4 null mutant, indicating that Cyp6d4 is not critical for the metabolism of vital endogenous substrates.
Breath testing with a mid-IR laser spectrometer

A mid-IR tunable diode laser absorption spectrometer (TDLAS) equipped with a multiple-pass gas cell was used to measure breath samples from a number of student volunteers at the University of Oklahoma. Test subjects included one to two pack-a-day cigarette smokers and non-smokers. The concentrations of four different molecules, N2O, 12CO2, 13CO2 and CO, were measured by each laser scan in the 2206.1 cm-1 to 2207 cm-1 spectral range. The average concentration of nitrous oxide (N2O) increased slightly for smokers versus non-smokers and was generally higher (12%) than the approximately 255 ppm concentration measured in ambient air. Carbon monoxide concentrations, however, were much higher in breath samples from cigarette smokers. Ambient concentrations of carbon monoxide, approximately 0.4 ppm, increased from approximately 1.0 ppm in non-smokers to levels over 13.4 ppm in smokers. These measurements provide clear evidence of the well-known effect that cigarette smoking has on replacing oxygen with carbon monoxide in human hemoglobin. Carbon dioxide concentrations of smokers were generally decreased by approximately 12%. Mid-IR laser measurements also provided 13CO2/12CO2 isotope ratio values, and smokers had a approximately 30% greater concentration of isotopic 13C in their breath. The possible mechanisms for 13CO2 isotopic increases are at present unknown. Overall, long-path TDL spectroscopy of exhalation products is a uniquely powerful tool. The TDL systems can be used for noninvasive diagnosis of a wide range of metabolisms and pathologies.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Dielectric and electrical transport properties of biopolymers

A new capacitive test structure is used to characterize biopolymers at microwave frequencies. The new test structure is comprised of a parallel plate capacitor, combined with coplanar waveguide-based input and output feed lines. This allows electrical measurements to be taken easily under an applied DC electric field and at various temperatures. The dielectric properties are characterized for two biopolymer thin films: a deoxyribonucleic acid (DNA)-based film and a bovine serum albumin (BSA)-based film. These bio-dielectric thin films are compared with a standard commercial polymer thin film, poly[Bisphenol A carbonate-co-4,4'(3,3,5-trimethyl cyclohexylidene) diphenol], also known as amorphous polycarbonate (APC).
Corrosion Test for Dental Amalgam

A corrosion test for dental amalgam, based on controlled potential coulometry, provides an index of corrosion susceptibility. A special cell was designed, and optimum test conditions were determined. The test can be used for the rating of amalgams, and in studies of the effect of variables on the corrosion resistance.
The Transferrin Receptor Binding Site on HFE, the Class I MHC-related Protein Mutated in Hereditary Hemochromatosis

HFE is a class I major histocompatibility complex (MHC)-related protein that is mutated in patients with the iron storage disease hereditary hemochromatosis. HFE binds tightly to transferrin receptor (TfR), the receptor that mediates uptake of iron-loaded transferrin. The binding affinities for TfR of HFE mutants, designed using the HFE crystal structure, were measured using biosensor assays. The results allow localization of the TfR binding site on HFE to the C-terminal portion of the α1 domain helix and an adjacent loop, a region distinct from the ligand binding sites on class I MHC and related proteins. A biosensor-derived pH-dependent affinity profile for the HFE-TfR interaction is discussed in terms of HFE's hypothesized role in intracellular trafficking.
Dynamic Modeling of Loads in Stability Studies

This paper emphasizes the need for a correct representation of electrical loads in stability studies. Several series of load-voltage tests performed on the Southern California Edison Company system are described. The test results are summarized and used as the basis for individual bus load representation.
Further Observations on Sex-Influenced Activity of 3β-Hydroxysteroid Dehydrogenase of Rat Liver1

Recent studies of the 3β-hydroxysteroid dehydrogenase of rat liver have revealed that the magnitude of the sex difference previously reported (1, 2) depends on the concentration of tissue used for the assay. With low tissue concentrations, enzymatic activity was proportional to concentration and approximately equal for both sexes. Activity departed from proportionality at high tissue concentration, the deviation being greater with livers of females than of males, so that, at tissue concentrations previously used, activities of liver preparations from female rats were 1/10-1/3 those found with livers of male rats. Plots of enzyme activity against tissue concentration with livers of female rats treated with testosterone or androstane-3,17- dione resembled the curves obtained with livers of male rats. The data obtained with livers of castrated male rats were similar to those obtained with livers of normal females. Part of the enzymatic activity of liver preparations was extractsble in soluble form. This solu...
Ordered Polymer Microstructures Synthesized from Dispersions of Liquid Crystal Mesogens

We have manufactured highly ordered polymer spheres, rods and fibrils from reactive mesogens using a template synthesis approach. The structures were fabricated by photo-polymerizing reactive mesogens in confining templates (spherical and cylindrical) while in the nematic phase. The spheres were produced from suspensions of a mesogen in glycerol and the rods and fibrils by a confining template method. The dielectric and optical anisotropy of the liquid crystalline monomer is captured by photo-polymerization. The balls are Electro-Mechano-Optical (EIMO) in nature undergoing a mechanical reorientation in the presence of an applied electric field, and therefore may be useful for electro-optic applications. The fibrils possess unusual properties due to their anisotropy and can be used to produce mesoscopic structures by self assembly. We present a number of these novel structures and methods for their fabrication.
Mutual adsorption of clay minerals and colloidal hydrous aluminum oxide—an electron microscopy investigation

Abstract The mutual adsorption of hydrous aluminum oxide and several clay minerals has been investigated as a continuation of the study reported previously by McAtee and Shaw. Electron micrographs of the alumina-kaolin mixtures qualitatively indicate that the alumina adsorbs more on the kaolin edges with lesser amounts adsorbed on the basal surfaces, especially at the higher concentrations of alumina. Throughout the concentration range studied, which extended through the floculation point and to redispersion of the kaolin, no curling of the kaolin was observed. The electron micrographs of the alumina-sodium montmorillonite mixtures showed large amounts of adsorption of alumina on the clay basal surfaces. They also clearly showed that the maximum curling of the montmorillonite platelets occurred at the flocculation point, and beyond that point redispersion and a flattening out of the clay particles took place.
The cAMP signal from Dictyostelium discoideum amoebae.

Abstract Dictyostelium discoideum cells were allowed to differentiate on agar for 600 min at room temperature. All of the cells were then competent to relay or amplify a cAMP signal, but none to produce a cAMP signal autonomously. The cells were stimulated with cAMP concentrations ranging from 10−9 to 3.5 × 10−7 M. Populations of 106 cells could amplify an initial cAMP concentration of 2.5 × 10−9 M with a low probability, while an initial cAMP concentration of 5 × 10−8 M always induced a response. An initial cAMP concentration of 1.2 × 10−7 M induced the maximum cellular release of cAMP observed; this corresponded to 3 × 107 molecules per cell. No cellular release of cAMP was detected for initial cAMP concentrations of 3 × 10−7 M or more. The amplification of a 10−7 M cAMP stimulus was complete within 8 sec, indicating the pulsatile nature of the cellular release of cAMP. The phosphodiesterase (PDE) activities of D. discoideum cells were measured over a wide range of cell densities. At densities above 7.5 × 104 cells/cm2, both cell-bound and extracellular (ePDE) activities declined, per cell, as cell density increased. These results are compared to ePDE activities derived from critical density measurements. We found that PDE activities were in the range of 10−13–10−14 moles of cAMP converted/cell/min under culture conditions consistent with normal aggregation.
The homeotic target gene centrosomin encodes an essential centrosomal component.

Abstract The centrosomin (cnn) gene encodes a protein associated with mitotic centrosomes in Drosophila melanogaster and is a target of homeotic gene regulation. Here we report that CNN is an essential component of the centrosome. Loss of zygotic cnn expression disrupts the development of the second midgut constriction, the gastric caeca, and the nervous system. Embryos that lack maternal as well as zygotic cnn expression display defects in nuclear division, chromosome alignment, and microtubule organization, while adult flies that are mosaic for cnn − cells exhibit defects indicative of a block in cell proliferation. We propose that cnn provides an example of homeotic genes directly regulating the accumulation of essential cellular proteins to carry out segment-specific morphogenetic functions.
AX one degree of freedom nominal association model for testing independence in two-way contingency tables

In testing the independence of the row and column variables in a two-way contingency table, the standard Pearson and likelihood ratio chi-square statistics often have low power, especially as the dimensions of the table increase. In this paper, one degree of freedom tests of independence based on likelihood ratio and score statistics from an association model for tables with nominal row and column classifications are described. The score statistic is especially easy to use, since it can be expressed in closed form, is simple to compute, and has size and power properties which are only slightly inferior to those of the more complicated likelihood ratio statistic.
Bacteroides in the Infant Gut Consume Milk Oligosaccharides via Mucus-Utilization Pathways

Summary Newborns are colonized with an intestinal microbiota shortly after birth, but the factors governing the retention and abundance of specific microbial lineages are unknown. Nursing infants consume human milk oligosaccharides (HMOs) that pass undigested to the distal gut, where they may be digested by microbes. We determined that the prominent neonate gut residents, Bacteroides thetaiotaomicron and Bacteroides fragilis , induce the same genes during HMO consumption that are used to harvest host mucus glycans, which are structurally similar to HMOs. Lacto- N -neotetraose, a specific HMO component, selects for HMO-adapted species such as Bifidobacterium infantis , which cannot use mucus, and provides a selective advantage to B. infantis in vivo when biassociated with B. thetaiotaomicron in the gnotobiotic mouse gut. This indicates that the complex oligosaccharide mixture within HMOs attracts both mutualistic mucus-adapted species and HMO-adapted bifidobacteria to the infant intestine that likely facilitate both milk and future solid food digestion.
Synthesis and degradation of cyano‐containing aramids

Various aramids having a cyano group on the diamine ring were synthesized. Aramids containing a cyano group ortho to the amide bond underwent thermal degradation via a two step mechanism, whereas those containing a cyano group meta to the amide bond did not. The first step represented the loss of HCN resulting in benzoxazole polymers, which degraded further in the second stage producing high char yield at 900°C. The thermal studied of copolyamides from m-phenylenediamine, 2,4-diaminobenzonitrile, and iso- or terephthaloyl chloride showed that as the mole fraction of 2,4-DABN increased the initial decomposition temperature decreased, but the char yield and glass transition temperature increased gradually from the poly(1,3-phenylene isophthalamide) to the polycyanamide homopolymer. To confirm the nucleophilic displacement reaction mechanism rather than isomerization cyclization suggested by Barashkov et al. for aramids with the cyano group ortho to the amide bond, a high-temperature cell attached to a FT-IR spectrometer were employed. Model compound studies also showed evidence for the benzoxazole ring formation.
In vivo microdialysis sampling coupled to liquid chromatography for the study of acetaminophen metabolism

Abstract In vivo microdialysis sampling coupled to liquid chromatography is a powerful tool for the study of drug metabolism. This technique is illustrated by investigating the pharmacokinetics of acetaminophen in the blood and liver of an anesthatized rat. The pharmacokinetics of the sulfate and glucuronide metabolites as well as the parent acetaminophen can be determined with high precision using microdialysis sampling. Microdialysis samples can be collected at a high rate from several sites without fluid loss with a single animal. Because the animal serves as its own control better data can be obtained. Liquid chromatography provides determination of multiple analytes per sample for metabolic profiling. This technique will provide more accurate and precise pharmacokinetic data while requiring fewer animals.
Criterion learning in rule-based categorization: simulation of neural mechanism and new data.

Abstract In perceptual categorization, rule selection consists of selecting one or several stimulus-dimensions to be used to categorize the stimuli (e.g., categorize lines according to their length). Once a rule has been selected, criterion learning consists of defining how stimuli will be grouped using the selected dimension(s) (e.g., if the selected rule is line length, define ‘long’ and ‘short’). Very little is known about the neuroscience of criterion learning, and most existing computational models do not provide a biological mechanism for this process. In this article, we introduce a new model of rule learning called Heterosynaptic Inhibitory Criterion Learning (HICL). HICL includes a biologically-based explanation of criterion learning, and we use new category-learning data to test key aspects of the model. In HICL, rule selective cells in prefrontal cortex modulate stimulus–response associations using pre-synaptic inhibition. Criterion learning is implemented by a new type of heterosynaptic error-driven Hebbian learning at inhibitory synapses that uses feedback to drive cell activation above/below thresholds representing ionic gating mechanisms. The model is used to account for new human categorization data from two experiments showing that: (1) changing rule criterion on a given dimension is easier if irrelevant dimensions are also changing (Experiment 1), and (2) showing that changing the relevant rule dimension and learning a new criterion is more difficult, but also facilitated by a change in the irrelevant dimension (Experiment 2). We conclude with a discussion of some of HICL’s implications for future research on rule learning.
Solid oxide cells with zirconia/ceria Bi-Layer electrolytes fabricated by reduced temperature firing

Anode-supported solid oxide cells (SOCs) with thin bi-layer Y0.16Zr0.92O2−δ (YSZ)/Gd0.1Ce0.9O1.95 (GDC) electrolytes were prepared by a reduced-temperature (1250 °C) co-firing process enabled by the addition of a Fe2O3 sintering aid. The Fe2O3 amounts in the layers affected the formation of voids at the GDC/YSZ interface; the case with 1 mol% Fe2O3 in the YSZ layer and 2 mol% Fe2O3 in the GDC layer yielded minimal interfacial voids, presumably because of optimized shrinkage matching between the electrolyte layers during co-firing. The best cells yield fuel cell power density at 0.7 V in air and humidified hydrogen of 1.74 W cm−2 (800 °C) and 1.0 W cm−2 (700 °C). Under electrolysis conditions, i.e., air and 50 vol% H2O–50 vol% H2, the best cell area specific resistance is 0.12 Ω cm2 at 800 °C and 0.27 Ω cm2 at 700 °C. This excellent cell performance was explained by a number of factors related to the reduced firing temperature: (1) low electrolyte resistance due to minimization of YSZ/GDC interdiffusion; (2) minimal zirconate phase formation between the YSZ and the La0.6Sr0.4Fe0.8Co0.2O3 (LSFC) cathode because of the dense GDC barrier layer; (3) high three phase boundary density in the Ni–YSZ anode functional layer; and (4) good pore connectivity in the Ni–YSZ support. Preliminary life testing under fuel cell and electrolysis operation shows promising cell stability.