cssi/SciSciGPT-SciSciNet huggingface dataset:
Ferritin, transferrin and iron concentrations in the cerebrospinal fluid of multiple sclerosis patients.

The concentrations of ferritin, transferrin and iron were measured in the cerebrospinal fluid (CSF) of multiple sclerosis (MS) and control patients. Ferritin levels were significantly elevated in the CSF of chronic progressive active MS patients (4.71+/-0.54 ng/ml) compared to levels in normal individuals (3.07+/-0.17 ng/ml). MS patients with active or stable relapsing-remitting disease had ferritin levels that were comparable to those found in normal individuals. There were no significant differences in transferrin or iron levels in the CSF between MS and normal individuals. Both ferritin and transferrin levels were elevated in patients that had high CSF IgG values but not in patients with a high IgG index. Since ferritin binds iron, the increase of CSF ferritin levels in chronic progressive MS patients could be a defense mechanism to protect against iron induced oxidative injury. Ferritin levels could be a laboratory measure that helps to distinguish between chronic progressive and relapsing-remitting MS.
Improved sorbent for high-temperature production of oxygen-enriched carbon dioxide stream

Perovskite-type La−Sr−Co−Fe metal oxides have been demonstrated as sorbents in a high-temperature sorption separation process for production of an oxygen-enriched gas stream for oxycombustion application. This paper reports on characteristics and fixed-bed performance of improved perovskite-type sorbents, Sr−Ca−Co−Fe oxides, in comparison with a reference La−Sr−Co−Fe oxide sorbent for high-temperature production of an oxygen-enriched carbon dioxide stream. The optimum composition of Sr0.5Ca0.5Co0.5Fe0.5O2.47 (SCCF) is identified through study of carbonation (oxygen desorption) kinetics of Sr−Ca−Co−Fe oxides with different Ca and Fe concentrations. Carbonation kinetics of SCCF were studied at different temperatures from 700 to 900 °C. Below 750 °C, interaction of SCCF with carbon dioxide results in formation of Sr and Ca carbonates. At higher temperature, SCCF turns to form oxides of the respective metals under a stream of carbon dioxide. The improved sorbent has a faster oxygen desorption kinetic rate and...
Absence of developmental incompatibility in hybrids between rainbow trout and two subspecies of cutthroat trout.

We examined the developmental rate of hybrids between rainbow trout (Salmo gairdneri) and two subspecies of cutthroat trout: westslope cutthroat trout (Salmo clarki lewisi) and Yellowstone cutthroat trout (Salmo clarki bouvieri). These taxa show considerable genetic divergence at 42 structural loci encoding enzymes; the mean Nei's d between the rainbow trout and the two species of cutthroat trout is 0.22. We used four measures of developmental rate: time of hatching and yolk resorption, rate of increase in activity of four enzymes, and time of initial detection of seven isozyme loci. The two cutthroat trout subspecies reached hatching and yolk resorption earlier than rainbow trout. Cutthroat trout had higher relative enzyme activities than rainbow trout from deposition of eye pigment to hatching. There was no difference in the rate of increase in enzyme activity or time of initial expression of these loci between these species. Hybrids showed developmental rates intermediate or similar to that of the parental species using all measures. Our results indicate an absence of regulatory and developmental incompatibility between these taxa.
A phenomenological model of the mechanical properties of microplastic surface grains during fatigue

Abstract Fatigue-induced changes in flow stress, yield strength and strain hardening coefficient in a microplastic grain at a metallic surface are modeled by considering the deformation of a composite grain structure, composed of a deformable matrix with one flow stress penetrated by slip bands having a second flow stress. Over a gauge length that is large compared with the slip band spacing, the average material properties change progressively as the band density increases with fatigue. Expressions for the dependence of the material properties on grain size, cyclic stress amplitude and fatigue duration are derived by assuming that new bands nucleate at sources interior to the grain, at a rate controlled by a cumulative hysteretic energy. Points of agreement between the model and experimental observations of the microplastic deformation behavior in an aluminum 2219-T851 alloy are discussed.
Distributed multi-agent microgrids: a decentralized approach to resilient power system self-healing

The predominance of recent self-healing power system research has been directed towards centralized command and control functions. In this paper, a decentralized multi-agent control method for distributed microgrids is introduced. Given the complexity of a large power system spanning hundreds of miles and comprised of numerous microgrids, it is potentially unrealistic to expect that centralizing total system control functions is feasible. Therefore, the authors are particularly interested in dispersing decision-making by utilizing smart microgrid control agents that cooperate during normal and emergency situations. The combination of microgrids and agent-based control can improve power system resiliency. The method described herein lays the groundwork for a comprehensive microgrid control architecture that strikes a balance between the multiple intra-microgrid objectives defined by local operator and the situational demands of the microgrid collective as part of the power system. In this way, both self-interest and cooperation can arise, allowing microgrid agents to successfully transition from normal operations to an emergency condition and back again when conditions have resolved, independent of a central supervisor. The decentralized multi-agent methods for microgrids explored in this paper help to support what may be an enabling technology of future smart grids.
Effects of irrigation on the chemical properties of a soil in the western san joaquin valley, California

Abstract Chemical properties of a native and irrigated soil in the arid, western portion of the San Joaquin Valley of California were determined. Both soils formed from alluvium deposited less than 500 years ago and lacked significant pedogenic development. The irrigated soil, which had been cultivated for 8 years, contained approximately one half the soluble salt (2120 vs. 5600 kg ha−1) and soluble Se (96 vs. 222 g ha−1) of the native soil. Leaching reduced the total CaCO3 content of the irrigated soil by 56 x 103 kg ha−1 from that of the native soil. Based on stable C isotope analysis, it was estimated that approximately 33% of the total CaCO3 in the irrigated soil had dissolved and reprecipitated during the period that it had been cultivated.
Production of N+∗ from N2 + hv: Effective EUV emission yields from laboratory and dayglow data

Abstract Photodissociative ionization of N2 into the unbound N + 2 H 2 Σ g + state is identified as the parentage of a number of N+ and N excited states that contribute to the u.v. dayglow. Yields have been obtained for the production of extreme ultraviolet emission lines of N+ (and N) from a laboratory experiment using a broad-band synchrotron radiation source with fluorescence spectroscopy. The yields are termed “effective”, in that they are constant percentages of the H state cross section. These are compared with effective yields needed to reproduce NII 1085 and 916 A lines from four dayglow observations using a model of solar energy deposition and photoelectron production and loss in the Earth's thermosphere. The 1085 A effective yield measured in the laboratory (18%) agrees with that from the dayglow data (average of 17%) to well within experimental uncertainties. Thus, we conclude that photodissociative ionization of N2 is the primary source of the Nil 1085 A dayglow. However, there is an order of magnitude discrepancy among the various dayglow observations of the 1085/916 intensity ratio, only one of which is consistent with the laboratory observation of 4.4. Neither contamination by other dayglow features nor atmospheric extinction can account for the disparities. Laboratory measurements of N2 and O2 absorption cross sections at these wavelengths are also reported.
Breast tumor cells with PI3K mutation or HER2 amplification are selectively addicted to Akt signaling.

Background Dysregulated PI3K/Akt signaling occurs commonly in breast cancers and is due to HER2 amplification, PI3K mutation or PTEN inactivation. The objective of this study was to determine the role of Akt activation in breast cancer as a function of mechanism of activation and whether inhibition of Akt signaling is a feasible approach to therapy. Methodology/Principal Findings A selective allosteric inhibitor of Akt kinase was used to interrogate a panel of breast cancer cell lines characterized for genetic lesions that activate PI3K/Akt signaling: HER2 amplification or PI3K or PTEN mutations in order to determine the biochemical and biologic consequences of inhibition of this pathway. A variety of molecular techniques and tissue culture and in vivo xenograft models revealed that tumors with mutational activation of Akt signaling were selectively dependent on the pathway. In sensitive cells, pathway inhibition resulted in D-cyclin loss, G1 arrest and induction of apoptosis, whereas cells without pathway activation were unaffected. Most importantly, the drug effectively inhibited Akt kinase and its downstream effectors in vivo and caused complete suppression of the growth of breast cancer xenografts with PI3K mutation or HER2 amplification, including models of the latter selected for resistance to Herceptin. Furthermore, chronic administration of the drug was well-tolerated, causing only transient hyperglycemia without gross toxicity to the host despite the pleiotropic normal functions of Akt. Conclusions/Significance These data demonstrate that breast cancers with PI3K mutation or HER2 amplification are selectively dependent on Akt signaling, and that effective inhibition of Akt in tumors is feasible and effective in vivo. These findings suggest that direct inhibition of Akt may represent a therapeutic strategy for breast and other cancers that are addicted to the pathway including tumors with resistant to Herceptin.
Psychosocial functioning in youths at high risk to develop major depressive disorder.

ABSTRACT Objective To compare the psychosocial functioning of children and adolescents at high risk of major depressive disorder with youths with acute major depressive disorder and healthy controls. Method High-risk (n = 57), major depressive disorder (n = 71), and healthy control (n = 48) youths and their families were recruited from 1987 to 1996 and assessed for psychopathology using standardized instruments. Except for 16 children who had disruptive disorders, the high-risk children were free of psychopathology. A parent completed the Psychosocial Schedule to evaluate the mother–child, father–child, marital relationships, and child–friend relationships and the child's school performance. Results Overall, high-risk and healthy controls had similar psychosocial functioning. Marital relationships were worse in the high-risk children with psychopathology. Youths with major depressive disorder had significantly more psychosocial problems and school difficulties than those at high risk and healthy controls in most domains measured. Controlling for age, pubertal stage, race, sex, family composition, current and lifetime parental depression, and current and lifetime parental nonmood psychopathology yielded similar results. Conclusions The family and peer interactions of high-risk youths were similar to the interactions of healthy controls. Although family dysfunctional patterns seem to mainly depend on the child's depressive symptoms, longitudinal studies are needed to establish causality.
Expression of SV40 tumor antigen in SV40 transformed teratocarcinoma-derived cell lines

The relative importance of viral tumor antigen expression and the cellular background in the maintenance of a transformation phenotype was examined in five SV40-transformed teratocarcinoma-derived cell lines. These cell lines show qualitative differences in growth characteristics associated with transformation, and vary in their state of differentiation. Viral T antigen expression was evaluated by two criteria: 1) the amount of immunoprecipitated antigen in growing cells, and 2) the amount and rate of antigen synthesis in density-inhibited cells. There was no direct correlation found between retention, or rate of synthesis, of the viral T antigen and the degree of transformation. These findings imply that the cellular environment has a more important influence on the growth properties of a stably transformed cell than the quantitative levels of viral T antigen expression.
Older Women's Constructs of Their Lives: A Quantitative and Qualitative Exploration

In the present article, the lifespan construct model was applied to the lives of older women by administering the life drawing to a sample of seventy-eight community-dwelling elderly women. Respond...
Relating wavefront error, apodization, and the optical transfer function: on-axis case

The incoherent optical transfer function (OTF) describes contrast degradation and phase shifts of sinusoidal objects of all spatial frequencies and orientations. The OTF is calculated as either an autocorrelation of the pupil function or the Fourier transform of the point spread function. Even with fast algorithms, these calculations can be slow for a densely sampled pupil. Here, a linear expansion of the OTF is developed in which the expansion coefficients are related to the wavefront error and apodization coefficients. The advantage of such a representation is that the OTF can be quickly generated from parameters of the optical system.
Biologically Active Fluorescent Farnesol Analogs

We describe ten polyene analogs of farnesol, typified by 3,7,11-trimethyl-2,4,6,8,10-dodecapentenaldehyde oxime, which preserve the length, cross-section, and approximate hydrophobicity of farnesol. Four of the ten display strong quorum-sensing activity in the human pathogen Candida albicans, with IC(50) values for inhibition of germ-tube formation as low as 10 microM. The polyenes display absorption maxima between 320 and 380 nm, with the extinction coefficients for the oximes approaching 100,000. All but two of the analogs are fluorescent, with excitation maxima varying over the range of 320-370 nm. Oxime anti-4, which can undergo fluorescence excitation at wavelengths beyond 400 nm, is demonstrated to be useful for confocal fluorescence microscopic imaging of fungal cells. The farnesol analogs are also expected to be useful for detection of farnesol binding proteins and in determination of farnesol pharmacokinetics.
Surface fluctuation spectroscopy: A novel technique for characterizing liquid interfaces

Surface fluctuation spectroscopy is a dynamic light scattering technique which involves the detection of thermal fluctuations (capillary waves) that cover every liquid interface. The advantages of this technique over conventional mechanical methods are discussed. The signal resolution and precision are improved by using a grating heterodyne technique coupled with a digital correlator. Detailed calculations showed that, for the measured power spectrum (the Fourier transform of the correlation function) to take the Lorentzian shape, it is necessary that certain optical conditions be met. These conditions are demonstrated with experimental data collected for ethanol at the ambient temperature as a function of the wave number. Once the optical parameters are adjusted correctly, the experimental results show excellent agreement with the literature values. It is also demonstrated that, using microcomputer technology, the entire system can be automated.
The estimation of examiner error and the true transition probabilities for teeth or surfaces in dental clinical trials.

Abstract In this paper, a mathematical model for the observed joint transition frequencies of teeth (surfaces) from one state (carious, healthy) to the other is given in terms of the “true” joint frequencies and the probabilities of examiner error. The parameters of the model are estimated from tooth surface data from a dental field trial using several estimation procedures and several groupings of the surfaces. The model proposed here is a generalization of previous models by Carlos and Senning (1968) and by Lu (1968). Their estimation procedure is discussed in connection with the present data; alternative approaches are suggested and explored.
An Innovation That Worked — A Useful Reminder

The Education and Experience in Engineering (E3) Program was developed at Illinois Institute of Technology (IIT) in 1970. The Programs goals were: 1) to motivate students for continuous independent learning, 2) to educate engineers capable of bringing interdisciplinary knowledge to bear on problem solving, 3) to cause students to become honest and realistic evaluators of their own work as well as that of their associates, 4) to provide students the opportunity to learn how to work in teams of engineering and non-engineering professionals, and 5) to foster the development of diverse communication skills. The students acquired knowledge of the “core” curriculum by means of learning modules; beyond the core materials, students were encouraged to learn advanced materials on their own. Conventional classes were eliminated and seminars supported broadening of knowledge. Solving open-ended problems re-defined the role of faculty from lecturers to mentors and guides. Requirement of mastery in every aspect of the Program substituted for grades and students prepared comprehensive portfolios of their accomplishments. Since educational goals of the Program were clearly defined, prospective students were able to assess whether E3 would be suitable for them.
Blooms of surf-zone diatoms along the coast of the Olympic Peninsula, Washington. X. Chemical composition of the surf diatom Chaetoceros armatum and its major herbivore, the Pacific razor clam Siliqua patula

The surf diatom Chaetoceros armatum T. West, collected from its natural habitat along the Washington coast (USA), had a large inorganic component in the form of a clay coat (consisting of clay minerals, illite and montmorillonite) surrounding the cell chains: 63% of the dry weight of the natural material collected in November was inorganic. The organic fraction was composed of 67.6% lipid, 29.7% protein, and 1.3% carbohydrate. Culture cells were likewise high in protein and lipid and low in carbohydrate. Traces of chitin found in field samples were probably a contaminant, since chitin was absent from cultured cells. This diatom species serves as a major food source throughout the year for the Pacific razor clam Siliqua patula Dixon, which inhabits these same beaches. Protein constituted 47% and lipid 42% of the dry weight of razor clam tissue. The fatty acid distribution in the diatom lipid resembled that previously reported for other diatom species; similarly, the fatty acid distribution of the clam lipid was similar to that previously reported for other bivalve molluscs. The clam fatty acids differed in chain length and degree of saturation from those extracted from its food source, indicating an active fatty acid metabolism in the clam.
Results from using a new dyadic-dependence model to analyze sociocentric physician networks.

Professional physician networks can potentially influence clinical practices and quality of care. With the current focus on coordinated care, discerning influences of naturally occurring clusters and other forms of dependence among physicians' relationships based on their attributes and care patterns is an important area of research. In this paper, two directed physician networks: a physician influential conversation network (N = 33) and a physician network obtained from patient visit data (N = 135) are analyzed using a new model that accounts for effect modification of the within-dyad effect of reciprocity and inter-dyad effects involving three (or more) actors. The results from this model include more nuanced effects involving reciprocity and triadic dependence than under incumbent models and more flexible control for these effects in the extraction of other network phenomena, including the relationship between similarity of individuals' attributes (e.g., same-gender, same residency location) and tie-status. In both cases we find extensive evidence of clustering and triadic dependence that if not accounted for confounds the effect of reciprocity and attribute homophily. Findings from our analysis suggest alternative conclusions to those from incumbent models.
Expanding-Disk Rain Sensor Dry-Out and Potential Irrigation Savings

AbstractRain sensors are devices that connect to automatic irrigation systems to interrupt scheduled irrigation events as a result of rainfall. The objectives of this study were to evaluate the dry-out time of expanding-disk rain sensors and determine potential irrigation savings under several virtual irrigation schedules. Five rain sensor model/rainfall set point combinations were evaluated at a research site in north central Florida. The five configurations that were compared were Mini-Clik rain sensors with set points of 3, 6, and 13 mm (3MC, 6MC, and 13MC), the Wireless Rain-Clik (WL) rain sensor, and Toro rain sensor at 6 mm setting (6T). The evaluation period ranged from 1,150 days to 1,182 days across the various devices. For each configuration, data for each time a rain sensor switched between allow irrigation to interrupt irrigation modes were collected and compared with how long each stayed in interrupt mode and how much irrigation water a rain sensor could save. Changing the dry-out vents from ...
Self-aligning bipolar bend transducer based on long period grating written in eccentric core fibre

A long period grating-based bend sensor featuring direct bend sensitivity along with linear, bipolar curvature response is demonstrated. The sensor can be aligned for optimum sensitivity using the slight intrinsic curvature of the eccentric core fibre.
Reinvestigation of σ-allyl cations: High level Ab initio quantum mechanical predictions

Abstract The question of stability of sigma-delocalized allyl cations is reinvestigated by hybrid HF-DFT quantum mechanical calculations. These computations predict that the existing molecular proposals, for such effects, are not symmetrically delocalized systems.
The effect of cooking temperature on the functional properties of beef proteins: the role of ionic strength, pH, and pyrophosphate.

This study examined the effect of ionic strength (0·12 to 0·52), pH (5·50 and 6·00), pyrophosphate (PP) concentration (0 and 0·31%) and cooking temperature (52 to 87°C) on the cook yield (CY) and tensile strength (TS) of beef homogenates. Increasing the ionic strength, pH and pyrophosphate concentration increased the temperature at which cooking loss first occurred and decreased the temperature required for maximum TS. For most treatments, ionic strengths between 0·32 and 0·42 prevented cooking loss at all temperatures; the lower ionic strengths were required at the higher pH and PP concentration. Maximum TS occurred at 66°C for treatments that had no cooking loss between 60° and 75°C. For treatments that had cooking loss in this temperature range, TS increased linearly with increasing temperature; however, the TS values of these treatments were much lower than those in the former category. CY and TS were optimized by heating to 66°C. PP had a positive effect on both functional properties at ionic strengths >0·25 but a negative effect at ionic strengths <0·25.
Context and consistency in students' approaches to solving problems in engineering statics

This paper examines students' responses to conceptually identical equilibrium and equivalence concept questions given in slightly different contexts, two as part of a final exam requiring explanation and the other two as part of a concept inventory. Since equivalence questions are essentially equilibrium questions from a different perspective, students were asked to apply the same concepts from two different perspectives and in two different contexts. Ideally student responses would be independent of context, but examination of students' answer selections and explanations indicates that approximately 2 in 3 students are consistent in their answers for equilibrium or equivalence questions in different contexts, but only approximately 1 in 3 students is consistent for both types of questions in both contexts. This paper builds off of previous studies of students' responses to Engineering Statics concept questions, explains the questions and methodology used in the study, and presents the results of the study.
CS-free food contingencies and subsequent acquisition of conditioned suppression: No transfer effect

Following VI training for food, 32 rats received 12 CSs (levers retracted) over 2 days during which three of four groups received free food. CS-free food contingencies were positive, negative, or absent; the fourth group received CSs alone. Subsequent CER acquisition (3 days) on the baseline revealed only a significant trials effect. These findings question the generality of the transfer-of-control phenomenon.
Preliminary study of themes of meaning and psychosocial service use among informal cancer caregivers.

Objective:The burden experienced by informal caregivers (ICs) of patients with advanced cancer is well documented. ICs are at risk for anxiety and depression, as well as existential concerns that arise when a loved one is facing a terminal illness. Few psychosocial interventions focus on existential concerns of ICs. However, a growing body of literature indicates that finding meaning in the experience of being an IC for a person with cancer has the potential to buffer against burden. The purpose of this study was to collect preliminary descriptive data regarding caregiver burden, meaning, and psychosocial service use to inform the adaptation of a meaning-centered intervention for ICs.Method:Twenty-five caregivers and 32 patients completed brief, anonymous questionnaires that asked about their role as a caregiver or their perception of their loved one as a caregiver, caregiver burden, and psychosocial service use.Results:Caregivers and patients identified anxiety and depression as top correlates of burden experienced by caregivers, whereas guilt, issues with role/sense of identity, and self-care were additional areas of concern. The majority of caregivers were not receiving psychosocial services, although they almost unanimously reported desiring services. A greater proportion of patients than caregivers believed that an intervention designed to enhance meaning would ameliorate burden, but, nevertheless, close to three quarters of caregivers reported interest in participating in such an intervention.Significance of results:These study findings provide further support for, at a minimum, engaging ICs of persons with advanced cancer in interventions that address existential issues, mental health, self-care, and service use. Such interventions are likely to improve the quality of life of both patients with cancer and their ICs.
An alternative model of development? Co‐operation and flexible industrial practices in India

Going beyond the notion of macroeconomic flexibility, this paper argues that flexibility at the firm/industry level is crucial to rapid adjustment to changing economic circumstances. By examining various kinds of Japanese-type flexible industrial practices adopted by a few firms in the Indian automotive industry, I show that aside from promoting competitiveness and externalities, such practices institutionalize co-operation. Developing countries, like India, undergoing economic reforms and requiring industrial investments, need to strengthen such institutional arrangements, thereby ensuring employment security, skill development, and social stability. © 1998 John Wiley & Sons, Ltd.
Finding Folkman Numbers via MAX CUT Problem

Abstract In this note we report on our recent work, still in progress, regarding Folkman numbers. Let f ( 2 , 3 , 4 ) denote the smallest integer n such that there exists a K 4 -free graph of order n having that property that any 2-coloring of its edges yields at least one monochromatic triangle. It is well-known that such a number must exist [J. Folkman, Graphs with monochromatic complete subgraphs in every edge coloring, SIAM J. Appl. Math., 18 (1970), 19–24, J. Nesetřil and V. Rodl, The Ramsey property for graphs with forbidden complete subgraphs, J. Comb. Theory Ser. B, 20, (1976), 243–249]. For almost twenty years the best known upper bound, given by Spencer, was f ( 2 , 3 , 4 ) 3 ⋅ 10 9 [J. Spencer, Three hundred million points suffice, J. Comb. Theory Ser. A, 49 (1988), 210–217. Also see erratum by M. Hovey in Vol. 50, p. 323]. Recently, the authors and Lu showed that f ( 2 , 3 , 4 ) 130000 [A. Dudek and V. Rodl, On the Folkman number f(2, 3, 4), submitted] and f ( 2 , 3 , 4 ) 10000 [L. Lu, Explicit construction of small Folkman graphs, submitted]. However, it is commonly believed that, in fact, f ( 2 , 3 , 4 ) 100 . All previous bounds are based on an idea of Goodman [A.W. Goodman, On sets of acquaintances and strangers at any party, Amer. Math. Mon., 66 (1959), 778–783]. It seems that such methods will not yield substantial further improvement. In this note we will generalize this idea by giving a necessary and sufficient condition for a graph G to yield a monochromatic triangle for every edge coloring. In particular, for any graph G we construct a graph H such that G is Folkman if and only if the value of the maximum cut of H is less than twice the number of triangles in G. We believe this technique may be used to find a new upper bound on f ( 2 , 3 , 4 ) .
The biomechanics of walking shape the use of visual information during locomotion over complex terrain

The aim of this study was to examine how visual information is used to control stepping during locomotion over terrain that demands precision in the placement of the feet. More specifically, we sought to determine the point in the gait cycle at which visual information about a target is no longer needed to guide accurate foot placement. Subjects walked along a path while stepping as accurately as possible on a series of small, irregularly spaced target footholds. In various conditions, each of the targets became invisible either during the step to the target or during the step to the previous target. We found that making targets invisible after toe off of the step to the target had little to no effect on stepping accuracy. However, when targets disappeared during the step to the previous target, foot placement became less accurate and more variable. The findings suggest that visual information about a target is used prior to initiation of the step to that target but is not needed to continuously guide the foot throughout the swing phase. We propose that this style of control is rooted in the biomechanics of walking, which facilitates an energetically efficient strategy in which visual information is primarily used to initialize the mechanical state of the body leading into a ballistic movement toward the target foothold. Taken together with previous studies, the findings suggest the availability of visual information about the terrain near a particular step is most essential during the latter half of the preceding step, which constitutes a critical control phase in the bipedal gait cycle. Language: en
Combustion of a stretched carbon monoxide ligament with radiative heat losses

This article concerns a theoretical study of combustion in a stretched, one-dimensional carbon monoxide (CO) strip surrounded by air. The analysis includes the effects of radiative heat transfer and time-dependent strain. Solution of mass, species, and energy equations for a single-step, finite-rate reaction between CO and O2 is obtained for an externally imposed in-plane strain motion with strain rates up to 1000 s−1 and for several strain rate histories. The radiation heat loss from the flame zone to its surroundings is incorporated into the solution using the optically thin gas radiation approximation. The results indicate that unstretched flames are significantly influenced by the presence of radiative heat loss, resulting in thermal quenching. Although, CO consumption rates in positively stretched flames are unaffected by the effects of radiative heat loss, the structure of the flame zone is somewhat altered. The CO oxidation behavior is found to be dependent on the strain history. Although low-frequency (of the order of inverse diffusion time scale) fluctuations in the strain rate enhance the CO oxidation significantly, the flame does not respond to fast oscillations. Radiative heat losses can promote quenching during negative (compressive) strain periods in the strain history.
Synthesis and characterization of 1-D uranyl thiodigycolate coordination polymers

Abstract To explore the role of the organic linker in promoting curvature in hybrid uranyl materials, thiodiglycolic acid was used to create four U(VI) compounds: (C5H6N)2[(UO2)2(tdg)3](H2O) (1), (C5H6N)2[(UO2)2(tdg)3] (2), (C7H8)(C5H6N)2[(UO2)2(tdg)3](H2O) (3) and (C2H10N2)0.5[(UO2)2(tdg)(O)(OH)(H2O)](H2O)2 (4) (tdg = C4H8O4S). Each compound is composed of uranyl polyhedra that are connected through the organic linker to form a 1-D coordination polymer with varying degrees of curvature and are the first U(VI) thiodigycolate compounds to be characterized by X-ray diffraction. The structural features of these compounds were also compared to other dicarboxylate ligands (glutaric, oxydiacetic, and iminodiacetic acid) to identify key components that could lead to the rational design of hybrid materials.
The Space Shuttle—Evaluating an American icon

Abstract The Space Transportation System (STS), for better or worse, has dominated the US space program for some 30 years and is now an American icon. The Space Shuttle orbiters have flown over 120 missions and certainly accomplished some amazing feats, including the deployment of the International Space Station (ISS), the launch and double repair of the Hubble Telescope, a number of classified missions for the US defense establishment and the cementing of international cooperation in space. As the remaining Space Shuttle orbiters head toward various museums, it is timely to look at the STS program in terms of key US space policy decisions that have paralleled the Space Shuttle’s often troubled history. This article seeks, from both a historical and a policy perspective, to assess what might have been. While noting the major accomplishments of the STS, it also identifies what can best be characterized as major lost opportunities and flawed policy decisions that have had multi-billion dollar consequences. In this regard, the US Congress, the White House, and NASA leadership have all played a role. If there have been failings, they have not been by NASA alone, but the entire US space policy leadership.
Effects of selective dopamine D1- and D2-type receptor antagonists on the development of behavioral sensitization to 7-OH-DPAT.

The primary objective of this study was to determine whether the development of behavioral sensitization to the putative dopamine D3 receptor agonist 7-OH-DPAT could be prevented by either selective D1-type or D2-type dopamine receptor antagonists. In three experiments, male Wistar rats (250–350 g) were given seven to nine injections (at 48-h intervals) of 7-OH-DPAT (1.0 mg/kg, SC) or vehicle in combination with the D2-type dopamine antagonist eticlopride (0.3 mg/kg, SC), the D1-type dopamine antagonist SCH 23390 (0.1 or 0.2 mg/kg, SC), or vehicle. After the injections, the rats were tested for locomotor activity in photocell arenas for 2 h. In the first two experiments, after seven injections, all rats were tested for activity following vehicle injections to test for possible conditioning effects. In each experiment, after the last pre-exposure session, all rats were given a challenge injection of 7-OH-DPAT (1.0 mg/kg, SC) and tested for activity. Major findings were as follows: a) 7-OH-DPAT treatments produced a progressively greater increase in locomotor activity with repeated treatment; b) concurrent treatment with eticlopride or SCH 23390 (0.1 and 0.2 mg/kg) blocked the acute locomotor-activating effects of 7-OH-DPAT across days; c) eticlopride, but not SCH 23390, completely blocked the development of behavioral sensitization to 7-OH-DPAT. Although the low dose of SCH 23390 (0.1 mg/kg) produced a partial attenuation of sensitization, the higher dose (0.2 mg/kg) of SCH 23390 appeared to augment, rather than block, sensitization to 7-OH-DPAT; d) rats previously treated with SCH 23390 (0.2 mg/kg, but not 0.1 mg/kg) without 7-OH-DPAT displayed a hyperactive response to the 7-OH-DPAT challenge injection; and e) after vehicle injections, rats previously given 7-OH-DPAT, SCH 23390, or eticlopride either alone or in combination were more active than vehicle control rats. These findings suggest that the neurochemical mechanisms mediating the development of behavioral sensitization to 7-OH-DPAT may differ from those of other dopamine D2-type agonists such as quinpirole or bromocriptine. Moreover, these results demonstrate that hyperactivity responses following vehicle injections in drug-pretreated animals do not necessarily reflect conditioning mechanisms.
Mysid Locomotion and Feeding: Kinematics and Water-Flow Patterns of Antarctomysis Sp., Acanthomysis Sculpta, and Neomysis Rayii

ABSTRACT This study provides information on the kinematics and water currents generated by the swimming appendages of three mysidan species: Antarctomysis sp., Neomysis rayii, and Acanthomysis sculpta. From the kinematic analysis, we determined that the moving thoracic exopodites were spatially segregated along two axes, which reduced the interference between the ipsilateral swimming appendages. The posterior thoracic exopodites, particularly the three posteriormost appendages, varied the orientation of their paths, thereby influencing the trajectory of the exhalent stream. The predominant trajectory of the paired exhalent streams was in a ventroposterior direction, but the exhalent streams could adopt more pronounced dorsal or ventral directions relative to those more commonly observed. The fact that only one exhalent stream emerged from each side of the animal suggested that the exopodites were propelling water in a synergistic fashion. Cannon and Manton (1927) claimed that the elliptical motion of the exopodites produced both swimming currents and feeding currents, the so-called "axial currents" that flow medially between adjacent basipodites, joining together with an anteriorly directed current between the eighth pair of endopodites in the food groove to transport food to the mouth. Although we presented fine streams of fluorescein dye to tethered animals, we never observed lateral feeding currents or food groove currents. We concur with Depdolla (1923) and Attramadal (1981) that food enters the feeding basket only from the front.
Relationship between density, viscosity and structure of GeO2 melts at low and high pressures

Abstract A correlative study of the viscosity, density and structure of GeO 2 melts has been carried out at low and high pressures. It is observed that under isothermal (1425°C) conditions the viscosity decreases from 6.0 × 10 3 poise at 1 bar to 1.2 × 10 3 poise at 9.5 kbar. The maximum variation in the density of quenched GeO 2 glasses is from 3.62 ± 0.02 g cm −3 for glass formed from a liquid quenched at 1 atm and 1425°C to 3.95 ± 0.04 g cm −3 for glass formed from a liquid quenched at 18 kbar and 1700°C. The similarity of the Raman spectra of GeO 2 melt quenched at 1 atm (1425°C) and at 18 kbar (1700°C) implies that the scattering units in GeO 2 glasses quenched at low and high pressures are the same. The intensity of the Rayleigh tail, however, decreases in glasses quenched at successively higher pressures, the structure apparently becoming more ordered with increasing pressure. The Raman spectra of the GeO 2 polymorphs with quartz and rutile structures, crystallized at 1150°C and at 4 and 6 kbar, respectively, are distinct because of the difference in Ge coordination, resulting in a large difference in the frequency and intensity of the GeO symmetric stretching mode in the two polymorphs. A comparison of the Raman spectra of GeO 2 glasses with those of crystalline GeO 2 polymorphs shows that the local ordering in GeO 2 glass is similar to that of hexagonal GeO 2 in which Ge is tetrahedrally coordinated. The decrease in the viscosity of GeO 2 melt with increasing pressure cannot be attributed to a pressure-induced coordination change [1]. More likely, there is a systematic change in the nature of the GeO bond with increasing pressure. The increase in the degree of local ordering in GeO 2 melts quenched at high pressures does explain the progressive increase in melt density.
Mathematical modeling of hydgogen clearance blood flow measurements in peripheral nerve

The hydrogen clearance technique of blood flow measurement often yields biexponential washout curves. In peripheral nerve, arteriovenous shunt vessels may clear hydrogen gas, causing the fast component of a biexponential curve. We simulated the washout of hydrogen from nerve tissue in the vicinity of a large shunt vessel by modeling the diffusion of hydrogen through tissue to the vessel and its removal by a network of capillaries. We then determined the fast and slow clearance rates and the relative weights or contributions of the fast and slow components and found that they are affected by all of the model parameters.
A Review of Instability Mechanisms in Passivation Films

Over the past ten years a number of single and double-layer insulator structures have been studied for passivation of semiconductor device surfaces. This paper reviews the various charge instability mechanisms associated with these structures. These include ionic drift, polarization, slow electronic trapping, and double-layer effects. The known dependence of these effects on processing and material parameters is discussed and the current state-of-the-art for controlling these instabilities is reviewed.
Physiologic Evaluation of Lung Resection Candidates

This article reviews an evidence-based approach to the physiologic evaluation of patients under consideration for surgical resection of lung cancer. Adequate physiologic evaluation often includes a multidisciplinary evaluation, with complete identification of risk factors for perioperative complications and long-term disability including cardiovascular risk, assessment of pulmonary function, and smoking cessation counseling. Consideration of tumor-related anatomic obstruction, atelectasis, or vascular occlusion may alter measurements. Careful preoperative physiologic assessment helps to identify patients at increased risk of morbidity and mortality after lung resection. These evaluations are helpful in identifying patients who may not benefit from surgical management of their lung cancer.
Tuberculosis control policies in major metropolitan health departments in the United States: VI. Standard of practice in 1996

Since 1980, we have surveyed at 4-yr intervals the metropolitan health departments initially reporting > 250 cases of tuberculosis to determine the perceived standard of practice for tuberculosis control and the factors affecting formulation of treatment policies. Between 1992 and 1996, use of supervised short-course (6 to 9 mo) intermittent therapy with multiple drugs including isoniazid, ethambutol, pyrazinamide, and rifampin increased from 4.3% to 46% of all new patients. Pyrazinamide use for initial treatment for children has increased substantially and now predominates (74.2% of patients in 1996 versus 48.1% of patients in 1992). Duration of treatment, which was 20 ± 2.1 mo in 1980, is now 8.00 ± 2.29 mo in 1996. The incidence of human immunodeficiency virus–associated tuberculosis, which was virtually unrecognized in 1984, has remained the same between 1992 and 1996 (18.0%). As in previous years, there was a wide variance among health departments in the incidence ( 40%) of HIV-associated t...
Magnetic separation of synthetic goethites based on Al substitution: 57Fe Mössbauer analysis

Abstract High gradient magnetic separation has been performed on 1:1 mixtures of artificially prepared pure and 30 at% aluminum-substituted goethite over a series of applied fields up to 1 T. The magnetic susceptibilities of these materials are (34±3) and (46±3)×10 -8 m 3 /kg, respectively. Mossbauer spectra were recorded for both the retained and non-retained fractions. The aluminum-substituted material is more strongly retained by the magnetic filter, due to its paramagnetic character and higher susceptibility. The retained fraction is concentrated in the 30 at% aluminum-substituted goethite by a factor of about 2.42. Similar separations using smaller particle sized 28 at% aluminum-substituted goethite (magnetic susceptibility of (36±4)×10 -8 m 3 /kg) in place of the original substituted compound show that smaller particles are more easily retained and that particle size is as important as susceptibility in determining separation properties. Flow rate has only a minor effect up to 250 ml/min.
A study of the role of multiple site blood cultures in the evaluation of neonatal sepsis

The optimal number of blood cultures needed to document sepsis in an ill neonate has undergone little critical evaluation. Multiple site cultures may improve pathogen detection if intermittent bacteremia occurs, or if a low density of bacteria is present in the blood. We hypothesized, however, that bacterial clearance is slower and bacteremia more continuous in septic neonates, so that a single site blood culture should be sufficient to accurately document true septicemia. To determine the need for multiple site blood cultures in the evaluation of neonates for sepsis. Clinical data were prospectively collected for 216 neonates who had 269 pairs of blood cultures taken from two different peripheral sites for the evaluation of possible sepsis. A minimum of 1 ml of blood was obtained from the two peripheral sites within 15–30 min of each other. Based on prior retrospective data, we determined that 203 infants would need to have two site blood cultures to demonstrate a significant improvement in pathogen detection at an alpha of 0.05 and a beta of 0.20 (80%) power. A total of 186 culture pairs were taken for evaluation of early-onset sepsis in 186 neonates, while 83 pairs were drawn for evaluation of late-onset sepsis in 43 neonates. In all, 21 neonates from the late-onset group were evaluated more than once, and 12 neonates were evaluated for both early- and late-onset sepsis. In all, 20 (9.2%) of 216 neonates had 22 episodes of culture-proven sepsis at a median age of 18 days. All neonates with positive cultures had the same organism with a similar sensitivity pattern obtained from the two different peripheral sites. The other 196 study neonates had negative blood cultures from both sites. The single episode of early-onset sepsis was caused by Listeria monocytogenes, while all remaining episodes were late-onset with the following organisms: Staphylococcus epidermidis (7), methicillin-resistant Staphylococcus aureus (MRSA) (3), combined MRSA and Candida albicans (2), Candida albicans alone (2), late-onset Group B β-hemolytic Streptococcus (GBS) (2), Klebsiella pneumoniae (2), Enterococcus fecalis (1), Escherichia coli (1), and Serratia marcescens (1). Since no infant grew organisms from only one of the two sites, the data indicate that the diagnosis of sepsis would have been made correctly in all infants with a single site culture. Two site blood cultures for the initial evaluation of neonatal sepsis do not have a better yield in pathogen detection. Sepsis in neonates can be detected with no loss of accuracy with a single site blood culture with blood volume of ⩾1 ml.