cssi/SciSciGPT-SciSciNet huggingface dataset:
Critical dependence of neurons on mitochondrial dynamics.

The selective disruption of certain cell types — notably neurons — in diseases involving mitochondrial dysfunction is thought to reflect the high-energy requirements of these cells, but few details are known. Recent studies have provided clues to the cellular basis of this mitochondrial requirement. Mitochondria are regionally organized within some nerve cells, with higher accumulations in the soma, the hillock, the nodes of Ranvier and the nerve terminal. In the synaptic region, mitochondria regulate calcium and ATP levels, thereby maintaining synaptic transmission and structure. Defects in mitochondrial dynamics can cause deficits in mitochondrial respiration, morphology and motility. Moreover, mutations in the mitochondrial fusion genes Mitofusin-2 and OPA1 lead to the peripheral neuropathy Charcot-Marie-Tooth type 2A and dominant optic atrophy. Perhaps it is the strict spatial and functional requirements for mitochondria in neurons that cause defects in mitochondrial fusion to manifest primarily as neurodegenerative diseases.
New antimicrobial cycloartane triterpenes from Acalypha communis.

Three new cycloartane-type triterpenes, 16α-hydroxymollic (1), 15α-hydroxymollic (2), and 7β,16β-dihydroxy-1,23-dideoxyjessic acids (3), were isolated from the aerial parts of Acalypha communis. The structures of the novel triterpenes were determined by spectroscopic methods as well as chemical derivatization. These compounds were tested for their antimicrobial activity against Gram-positive and -negative bacteria. Compounds 1−3 exhibited moderate antimicrobial activity (MIC 8, 32, 8 μg/mL, respectively) against vancomycin-resistant enterococci. In addition, compound 1 was found to be active against methicillin-resistant staphylococci. In contrast, compounds 1−3 were poorly active against Gram-negative bacteria. Compound 3 was tested in an in vivo model; it did not provide protection to mice infected with Staphylococcus aureus.
Anisotropic radiative emission effects on deduced resonant-transfer-excitation cross sections.

The radiation emitted by an ion collisionally excited by an electron beam is anisotropic. We discuss two schemes, one for use with LS-coupling cross sections and one for intermediate coupling, whereby theoretical resonant-transfer-excitation cross sections can be modified to take account of this anisotropy when making comparisons with experimental results deduced from observations of radiation at a particular beam angle. We have carried out such calculations for a number of ions initially in an S state, viz. ${\mathrm{F}}^{6+}$, ${\mathrm{Ca}}^{\mathit{q}+}$ (q=16\char21{}19), and ${\mathrm{Nb}}^{\mathit{q}+}$ (q=29\char21{}31). In all cases, neglecting hyperfine structure, the allowance for anisotropic radiative emission at right angles to the beam axis was found to result in only a small increase (10\char21{}15 %) in the cross section over results that assumed isotropy. Allowance for hyperfine structure reduced even this anisotropy by 20% for $^{19}\mathrm{F}^{6+}$ (I=1/2) and by 80% for $^{93}\mathrm{Nb}$ (I=9/2) ions; results for $^{40}\mathrm{Ca}$ (I=0) ions remain unchanged.
Videotime: Selection and Structuring Family Social Time With Rented Commercially Prerecorded Electronic Media

Using in-depth interviews, this research investigates family members' processes for renting and watching commercially prerecorded video electronic media. The study finds that renting prerecorded video material is a negotiated process that begins in advance of viewing, and concludes that the social aspects of viewing are of paramount importance and concern to most family-oriented renters. In short, the viewers consider the time spent watching a rented video, or videotime, as family social time that is structured around this communal act. This study extends previous research in this area by explicating how families make decisions and negotiate the structuring of videotime.
THIN-LAYER CHROMATOGRAPHY OF RELATIVELY VOLUMINOUS SAMPLES.

THE principle of this method is that a relatively voluminous sample (50–100 µl.) is easily applied over a large area of chromatographic substrate and can then be swept into a narrow band by an advancing solvent front. This narrow band is used as the starting line for conventional thin-layer chromatography. The width of the band compares favourably with the diameter of spots applied by the time-consuming, conventional method of repeated application of microlitre amounts. We have used the method for the chromatography of amino-acids in aqueous solvents on 250-µ thick layers of both silica and cellulose, and the method should have general applicability.
Sulfur-containing amino acids decrease cisplatin cytotoxicity and uptake in renal tubule epithelial cell lines.

Purpose: Nephrotoxicity is one of the major dose-limiting side-effects of cisplatin (DDP). The disproportionate accumulation of cisplatin in kidney tissue may play an important role; however, therapeutic measures to prevent this prime cause of nephrotoxicity are not available. Because certain amino acids (AAs) have been reported to modulate DDP nephrotoxicity in vivo, we explored the potential of all 20 protein AAs, N-acetylcysteine and DL-homocysteine to reduce DDP cytotoxicity and uptake in S1, S3 (proximal tubule), and DCT (distal convoluted tubule) cell lines. Methods: Immortalized but non-transformed renal tubule epithelial cell lines, derived from specific portions of the nephron of an SV40 transgenic mouse, were grown to confluency and exposed to various concentrations of DDP for 1 h with or without concurrent exposure to AAs in an otherwise AA-free Krebs-Ringer buffer (KRB). After 1 h, cell layers were washed and replenished with medium for cytotoxicity assays, or processed immediately for the determination of DDP accumulation. Cytotoxicity was assessed 48 h later by an MTT assay, and DDP uptake after 1 h was determined by atomic absorption spectroscopy. Results: In an initial screening where the cells were concurrently incubated with 0.25 mM DDP and 1 mM AA for 1 h in KRB, only cysteine (Cys), methionine (Met), N-acetylcysteine and DL-homocysteine reduced DDP toxicity. This effect was enhanced at 5 mM AA and most potent for Cys, which reduced DDP cytotoxicity by 79 ± 3% in S3 cells, by 78 ± 12.2% in DCT cells, and by 19 ± 3.6% in S1 cells (P < 0.05). Reduction of cytotoxicity was less for Met, DL-homocysteine, and N-acetylcysteine, in decreasing order. All four AAs also inhibited DDP uptake in renal cells, with Cys as the strongest inhibitor. Inhibition of DDP accumulation by 1 mM Cys after 1 h was 39% in S3 cells, 38% in DCT cells, and 28% in S1 cells. Again, reduction of uptake was less for the three other AAs. Pre-complexing of DDP with Cys for 16 h increased its uptake by 8- to 30-fold compared with native DDP, but markedly inhibited its toxicity. Thus, pre-complexing of DDP with Cys could not explain the reduced uptake of DDP, but could partly account for the reduction in cytotoxicity. Double-reciprocal Lineweaver-Burk plots of DDP concentration-versus-uptake rates at a constant concentration of Cys suggested that Cys competitively inhibited DDP uptake in S1 and DCT cells, and in a more complex fashion in S3 cells. Conclusions: We conclude that Cys, Met, N-acetylcysteine, and DL-homocysteine differentially inhibit DDP toxicity and uptake in cultured S1, S3, and DCT cells, and that the inhibition of uptake, as well as the complexation of DDP with Cys within the cell, may prevent toxicity. The structural element R-CH(NH2)-[CH2]1–2-S-R, which is common to all four molecules, may play a crucial role in blocking the transport of DDP, and could have future clinical applications.
Irradiation Effects on the Behavior of Structural Materials at Elevated Temperature

A qualitative review of the effects of fast neutron irradiation on the mechanical behavior of materials used in the construction of Fast Breeder Reactor Core Components is presented in three sections. First, effects of preirradiation on the strength, ductility, elastic moduli, thermal creep, creep-rupture, and fatigue are discussed. Second, the phenomenon of irradiation induced swelling is explained and the effects of temperature, cold work, and stress on swelling are presented. Third, irradiation creep is defined and the effects of temperature, stress, and cold work on irradiation creep are discussed. The review is based on the most recently available experimental data on austenitic stainless steels.
A HYDROCLIMATOLOGICAL ANALYSIS OF THE RED RWER OF THE NORTH SNOWMELT FLOOD CATASTROPHE OF 1997

ABSTRACT: The flood hydroclimatology of the Grand Forks flood of April 1997, the most costly flood on a per capita basis for a major metropolitan area in United States history, is analyzed in terms of the natural processes that control spring snowmelt flooding in the region. The geomorphological characteristics of the basin are reviewed, and an integrated assessment of the hydroclimatological conditions during the winter of 1996 to 1997 is presented to gain a real-world understanding of the physical basis of this catastrophic flood event. The Grand Forks flood resulted from the principal flood-producing factors occurring at either historic or extreme levels, or at levels conducive to severe flooding. Above normal fall precipitation increased the fall soil moisture storage and reduced the spring soil moisture storage potential. A concrete frost layer developed that effectively reduced the soil infiltration capacity to zero. Record snowfall totals and snow cover depths occurred across the basin because of the unusual persistence of a blocking high circulation pattern throughout the winter. A severe, late spring blizzard delayed the snowmelt season and replenished the snow cover to record levels for early April. This blizzard was followed by a sudden transition to an extreme late season thaw due to the abrupt breakdown of the blocking circulation pattern. The presence of river ice contributed to backwater effects and affected the timing of tributary inflows to the main stem of the Red River. Only the absence of spring rains prevented an even more catastrophic flood disaster from taking place. This paper contributes to our understanding of the flood hydroclimatology of catastrophic flood events in an unusual flood hazard region that possesses relatively flat terrain, a north-flowing river, and an annual peak discharge time series dominated by spring snowmelt floods.
Applications of neural networks in high-speed communication networks

Modern communication networks are expected to have hundreds or thousands of network nodes to which thousands of users are connected. Neural networks can contribute to this emerging new telecommunication infrastructure by providing fast, flexible, adaptive, and intelligent control. This article discusses the neural networks used for solving various control problems in high-speed communication networks. >
Thermal activation analysis on the plastic deformation satisfied with the Cottrell-Stokes law

Abstract The Cottrel-Stokes law is studied at 300 K in copper by using the translating slope of stress relaxation curves expressed as log-log plots of stress and strain rate which is a sensitive indicator for the validity of the law. It becomes evident that the original law gives the infinite translating slope under the condition of the modified law which requires the product of effective stress and activation volume to be constant. The thermal activation analysis on the plastic deformation satisfied exactly with the Cottrell-Stokes law is then made. The change in activation distance due to normal strain rate change and the total activation energy are obtained to be 0.4–0.5 in the Burgers vector unit and 105 kJ/mol, respectively. Finally, it is concluded that the activation distance remains constant during tensile deformation satisfied with the Cottrell-Stokes law at a given strain rate and temperature.
Differential effects of aging on hepatic microsomal monooxygenase induction by phenobarbital and β-naphthoflavone

The influence of aging on hepatic microsomal monooxygenase induction by phenobarbital (PB) or β-naphthoflavone (BNF) was investigated in male Fischer 344 rats maintained in a constant environment. PB-induced increases in microsomal cytochrome P-450 content and NADPH-cytochrome c reductase activity were similar in rats aged 3–5 months (young-adult) and 24–25 months (old), but increases in benzephetamine N-demethylase activity were markedly diminished in the old rats. Separation of hepatic microsomal proteins by sodium dodecylsulfate gel electrophoresis demonstrated that aging decreased the induction by PB of a polypeptide with a molecular weight of 52,500. BNF-induced increases in microsomal cytochrome P-450 and nitroanisole O-demethylase activity were greater in old than in young-adult rats, and BNF induction of 55,000 and 57,000 molecular weight microsomal polypeptides was increased slightly in livers from old rats. The results indicate that age-related effects on monooxygenase induction vary with different inducers of the hepatic microsomal enzyme system.
A neural network identification system for space-borne GCMS pattern recognition

We present experimental results of training a neural network to perform chemical compound identification from a portable space-borne gas chromatographic mass spectrometer (GCMS). The GCMS data has distortion, peak overlap, and noise problems. A signal processing algorithm is first applied to the GCMS to detect the peaks and to clean the MS spectra. We design neural networks to be trained on a sub-set of chemicals that are closely related in the GC graph. Each sub-neural network then identifies the compounds within the sub-set. We design the training data using mostly NIST standard MS data. The NIST mass spectral data of multiple compounds are mixed to train the neural network to identify mixed species. Back-propagation learning algorithm is used to train the neural network. Good identification results have been obtained.
Tropical forest sheep on legume forage/fuelwood fallows

In Amazonian Ecuador, studies are being realized to intensify fallow periods by grazing African tropical forest type sheep (Red Afro-Colombian X Barbados Black Belly) on Asian tropical forest legume cover forage (Desmodium ovalifolium) under American tropical forest legume fuelwood trees (Inga edulis). The specific approach represents an innovative effort to address the complex problems associated with the pernicious use of less fertile lands by small-scale farmers and graziers in the humid tropics. The technologies developed are closely compatible with traditional socio-cultural patterns. For example, shifting cultivators are encouraged to plant contour strips of legume fuelwood trees in their cassava fields. With the cassava harvest, legume cover forage is planted between the fuelwood trees, to be grazed later by tropical forest sheep.
How Do Instructional‐Design Practitioners Make Instructional‐Strategy Decisions?

Many theories have been proposed to help instructional designers make instructional-strategy decisions, yet it is not clear if these theories are actually used by ID practitioners. This study used a web-survey to examine the design strategies of 113 ID practitioners. The survey asked respondents to rate how frequently they used learning or ID theories as well as 10 other design strategies, to help make instructional-strategy decisions. Respondents were also asked how often they used different information sources to learn about new theories, trends, and strategies, and to respond to a set of contrasting statements depicting objectivist vs. construc-tivist assumptions. The results indicate that ID practitioners most often rely on interaction with others both as a means of making instructional-strategy decisions and of learning about new theories, trends, and strategies. Only fifty percent of the respondents said they regularly use theories when making instructional-strategy decisions, using other design strategies more frequently instead; and most practitioners are eclectic in their underlying philosophical assumptions. Based on these results, we discuss implications for training and ongoing support of instructional designers.
MQuery: A Visual Query Language for Multimedia, Timeline and Simulation Data

Abstract This paper describes a visual query language that can express questions over multimedia, timeline and simulation data using a single set of related query constructs. A uniform model for multimedia types organizes image, sound, video and long text data in a consistent manner, giving multimedia schemas and queries a degree of data independence even for these complex data types. Information that possesses an intrinsic temporal element can be queried using a construct called a stream. Streams can be aggregated into parallel multistreams, thus providing a structure for querying and retrieving multiple sets of time-based information. The unified stream construct permits real-time measurements, numerical simulation data and visualizations of that data to be aggregated and manipulated using the same set of operators.
Pigment Quantitation and Analysis by HPLC Reverse Phase Chromatography: A Characterization of Antenna Size in Oxygen-Evolving Photosystem II Preparations from Cyanobacteria and Plants†

Photosystem II, the photosynthetic water-oxidizing complex, can be isolated from both plants and cyanobacteria. A variety of methods have been developed for purification of this enzyme, which can be isolated in several functional and structural forms. Knowledge of the pigment content of photosystem II preparations is important for precise spectroscopic, biochemical, and functional analysis. We have determined pigment stoichiometries in oxygen-evolving photosystem II preparations from plants and cyanobacteria. We have employed a solvent system for the isocratic elution of a reverse phase HPLC column in which we have determined the extinction coefficients of the relevant pigments. Pigments were extracted from four photosystem II preparations. These preparations included spinach photosystem II membranes [Berthold, D. A., Babcock, G. T., & Yocum, C. F. (1981) FEBS Lett. 134, 231-234], spinach photosystem II reaction center complexes [Ghanotakis, D. F., & Yocum, C. F. (1986) FEBS Lett. 197, 244-248], spinach photosystem II complexes [MacDonald, G. M., & Barry, B. A. (1992) Biochemistry 31, 9848-9856], and photosystem II particles isolated from the cyanobacterium, Synechocystis sp. PCC 6803 [Noren, G. H., Boerner, R. J., & Barry, B. A. (1991) Biochemistry 30, 3943-3950]. Pigment stoichiometries were determined using two different methods of data analysis and were based on the assumption that there are two pheophytin a molecules per photosystem II reaction center. The pigment stoichiometries obtained were comparable for the two methods of data analysis and agreed with previous biophysical and biochemical characterizations of the preparations. The average pigment stoichiometries (chlorophyll:plastoquinone-9 per 2 pheophytin a) determined using the two data analysis methods were as follows: photosystem II membranes, 274:3.2; photosystem II reaction center complexes, 78:2.5; Synechocystis PS II particles, 55:2.4; photosystem II complexes, 121:2.0.
Astressin B, a nonselective corticotropin-releasing hormone receptor antagonist, prevents the inhibitory effect of ghrelin on luteinizing hormone pulse frequency in the ovariectomized rhesus monkey.

Administration of ghrelin, a key peptide in the regulation of energy homeostasis, has been shown to decrease LH pulse frequency while concomitantly elevating cortisol levels. Because increased endogenous CRH release in stress is associated with an inhibition of reproductive function, we have tested here whether the pulsatile LH decrease after ghrelin may reflect an activated hypothalamic-pituitary-adrenal axis and be prevented by a CRH antagonist. After a 3-h baseline LH pulse frequency monitoring, five adult ovariectomized rhesus monkeys received a 5-h saline (protocol 1) or ghrelin (100-μg bolus followed by 100 μg/h, protocol 2) infusion. In protocols 3 and 4, animals were given astressin B, a nonspecific CRH receptor antagonist (0.45 mg/kg im) 90 min before ghrelin or saline infusion. Blood samples were taken every 15 min for LH measurements, whereas cortisol and GH were measured every 45 min. Mean LH pulse frequency during the 5-h ghrelin infusion was significantly lower than in all other treatments (P < 0.05) and when compared with the baseline period (P < 0.05). Pretreatment with astressin B prevented the decrease. Ghrelin stimulated cortisol and GH secretion, whereas astressin B pretreatment prevented the cortisol, but not the GH, release. Our data indicate that CRH release mediates the inhibitory effect of ghrelin on LH pulse frequency and suggest that the inhibitory impact of an insufficient energy balance on reproductive function may in part be mediated by the hypothalamic-pituitary-adrenal axis.
Characterization of liquefaction products: evolution of carbon dioxide and water during low-temperature oxidation

Abstract Evolution of carbon dioxide and water during aging of SRCII heavy distillate and of Synthoil has been studied at temperatures of 70°–105°C and times up to 200 hours. For both liquefaction products, gas evolution was negligible in nitrogen compared with that in oxygen. Under oxygen, rates of CO 2 and H 2 O evolution increased with increasing temperature. CO 2 evolution rates for both samples were relatively independent of time over the 100–200 hour period. At corresponding temperatures, the rate of CO 2 evolution was larger (2–2.5 times) from Synthoil product than from the SRCII. Experiments with SRCII showed that (a) CO 2 evolution was not limited by (gas-liquid) mass transfer; (b) the oxidizable species which decarboxylate (or give rise to water) in O 2 are present in finite amount; and (c) the rate-determining step in CO 2 evolution is the attack by O 2 on functionalities within the SRCII, not the decarboxylation step itself. Apparent activation energies for CO 2 evolution were about 17 kcal/mole for SRCII and 13 kcal/mole for Synthoil. Rates of H 2 O evolution in O 2 decreased with time of aging. Again, at corresponding temperatures the H 2 O evolution was substantially greater from Synthoil product than from SRCII. The molar ratio of H 2 O:CO 2 evolved varied with nature of sample, time, and temperature. The ratio was large (12–49), however, indicating that some of the sources of H 2 O and CO 2 were different. IR spectra of samples aged under N 2 were unchanged relative to unaged samples. A strong absorption band at 1700 cm −1 , characteristic of carbonyl groups, developed during O 2 -aging of these liquefaction products, the intensity increasing with increasing temperature and time of aging. A yellow condensate formed in the magnesium perchlorate absorption tube during the oxidative aging of these materials. IR analysis of the condensate indicated that it was primarily aliphatic in nature, with carbonyl functionality also present.
Electrochemical synthesis and characterization of mixed molybdenum–rhenium oxides

Abstract The electrodeposition of MoxRe1−xOy films (0.6 ≤ x ≤ 1) on indium-tin oxide (ITO) coated glass substrates from acidic peroxo-polymolybdo-perrhenate solutions is described. Trends in film growth were established as a function of potential from +0.4 V to −0.7 V vs Ag/AgCl by analyzing the composition and stoichiometry of the deposit using inductively coupled plasma mass spectrometry (ICPMS) and X-ray photoelectron spectroscopy (XPS). These experiments show that the concentration of rhenium increases linearly with the deposition potential and that the deposits are mixed-valent containing up to five different metal oxidation states (i.e., MoIV, MoV, MoVI, Re0, ReIV). Electroanalytical techniques were used to explore the deposition mechanism, including chronocoulometry, cyclic voltammetry, spectroelectrochemistry, and electrochemical quartz crystal nanogravimetry (EQCN). At potentials positive to −0.26 V, perrhenate (ReVIIO4−) behaves as a redox mediator to accelerate the deposition of a mixed-valent molybdenum oxide, but at more negative potentials mixed molybdenum–rhenium oxides are produced.
Effect of light irradiance on the production of sulfolipids from Anabaena 7120 in a fed-batch photobioreactor.

Sulfolipids have recently emerged as promising antiHIV and antitumor therapeutics. These lipids have been found in association with the photosynthetic apparatus in most photoautotrophic organisms. To date there have been no quantitative studies on the effect of environmental factors on the production of sulfolipid. In this study, we present results on the effect of light irradiance on the production of sulfolipids using the cyanobacteriumAnabaena 7120. The cyanobacteria are grown in a 2 L fedbatch photobioreactor at various external-light intensities. Total lipids are extracted using the Folsch procedure and sulfolipids are quantified using thin-layer chromatography and scanning densitometry. We have achieved a maximum of 14 mg sulfolipid/g dry weight of cell. Our results indicate that there are two stages in the specific rate of production of sulfolipids, one in the declining exponential-growth phase of the cells and the other in the light-limited stage of growth.
Accelerated Hair Growth in the Rat After Adrenalectomy Cannot be Attributed to the Thyroid

SummaryWhen the hair is removed from the backs of underfed rats it does not grow externally for long periods. Upon adrenalectomy of such underfed rats, the hair grows on their backs in 8 or 9 days. Histological sections show no increased activity of the thyroid in such adrenalectomized animals. When underfed individuals are thyroidectomized one to 21 days previous to adrenalectomy, the hair, likewise, grows in 8 or 9 days after removal of the adrenals. There is, therefore, no evidence that the thyroid is responsible in any way for the rapid growth of hair in the rat following adrenalectomy.
Synthesis and cellular localization of porphyrinic pigments

To determine factors that govern the uptake preference of photosensitizers in cellular organelles of human adenocarcinoma cells, diarginyl-dialkoxy- and diarginyl-dimethoxyphenylporphyrins (TPPs) and two of their corresponding indium(III) complexes were synthesized, characterized and incubated in androgen-sensitive human prostate adenocarcinoma cells LNCaP . The porphyrins revealed properties that are of importance for phototherapy. They are water-soluble, have their fourth Q-band absorbing at ≈ 650 nm, are taken up in relatively high concentrations in LNCaP cells, and are phototoxic. Colocalization and phototoxicity studies revealed that all porphyrins localized preferentially to the lysosomes and invoked cell death when excited with 650 nm light. Compared to the corresponding methoxy-substituted TPPs, the diargininyl-dialkoxy-substituted porphyrins localized to a small extent in the mitochondria. The corresponding In(III) chloride complexes that are slightly less water-soluble were also taken up in the lysosomes of LnCaP cells. When the TPPs were compared to a pheophorbide derivative recently synthesized in our laboratory, it was determined that the TPPs have a preference for lysosomal localization, whereas the pheophorbide derivative co-localized to the mitochondria. Phototoxicity studies revealed that the longer chain dialkoxyTPPs were more effective in cell killing and induced greater morphological changes typical of apoptotic cell death than the shorter chain methoxy substituted porphyrins. The In(III) complexes seemed to be the most phototoxic. These results highlight that the type, nature, and substitution pattern of the chromophore modulate the extent of apoptotic cell death and influence cellular targeting.
Physician Brain Drain from Sub-Saharan Africa: Exploring the Utility of an Eco-psychopolitical Validity Framework for Medical Migration Research

Abstract In-depth understanding of any critical social issue requires investigators to use analytical tools that reflect the complexity of the social issue of interest. Toward this aim, I examine the medical brain drain from Sub-Saharan Africa to the United States through the lens of the eco-psychopolitical validity model (see, Christen & Perkins, 2008; Prilleltensky, 2008), an integrative approach that stresses the combined influences of structural factors, individual agency, and power at play in human dynamics and social systems. By adapting the eco-psychopolitical validity model to the study of medical skilled migration, I construe migration as a liberating venture articulated around the triadic process of oppression, empowerment, and wellness. If migrants yearn to breathe free, then emigre physicians are essentially in pursuit of liberation and wellbeing. However, in a world of profound health disparities, where the increasing emigration of medical doctors from resource-constrained countries ultimately leads to loss of lives in the communities left behind, migrant doctors’ individual agency and the multilevel contexts that enable or constrain them to emigrate require critical reflection. Some emerging themes and variations of an ongoing qualitative study are examined using the eco-psychopolitical validity paradigm.
Depletion of acetylated α‐tubulin during microtubule purification from bovine brain gray and white matter regions

We have followed the fate of acetylated alpha-tubulin during microtubule (MT) purification from both gray matter- and white matter-enriched bovine brain regions, using quantitative immunoblot assays employing well characterized monoclonal antibodies specific for acetylated alpha-tubulin and all beta-tubulins. Our results show that crude homogenates from both gray matter and white matter brain regions contain the same proportion of acetylated alpha- to total tubulin. We have found that the acetylated isoform cycles more efficiently with MTs from gray matter than with MTs from white matter. However, the resultant purified MT preparations from both gray and white matter regions are greatly depleted in the acetylated isoform compared to the tubulin in the initial homogenates because most of the acetylated alpha-tubulin from both tissue sources partitions with the cold-insoluble fraction of the initial brain homogenate. A low percentage of the acetylated alpha-tubulin in brain homogenates does become incorporated into MTs initially, but this subpopulation of acetylated alpha-tubulin then becomes associated with a cold- and calcium-insoluble fraction of the MT preparation. These results demonstrate that the standard brain MT and tubulin preparations used by most investigators for in vitro studies are greatly depleted in acetylated alpha-tubulin, and thus provide poor model systems for the analysis of the function of this tubulin isoform.
Static Barrier MIMD

In this paper, we describe and analyze the performance of a new architectural construct - an efficient synchronization mechanism called "Static Barrier MIMD" or SBM. Unlike traditional barrier synchronization, the proposed barriers are designed to allow static (compile-time) code scheduling to eliminate some synchronizations. The static barrier MIMD hardware is more general than most hardware barrier mechanisms, allowing any subset of the processors to participate in each barrier. The barriers execute in a small number of clock ticks, and processors proceed simultaneously past the barrier. The performance of idealized barrier schedules is examined to gain insights into code scheduling for barrier MIMD machines.
Muscle function in animal movement: passive mechanical properties of leech muscle

We investigated passive properties of leech body wall as part of a larger project to understand better mechanisms that control locomotion and to establish mathematical models that predict such dynamical behavior. In tests of length-tension relationships in 2-segment-long preparations of body wall through step-stretch manipulations (step size = 1 mm), we discovered that these relationships are nonlinear, with significant hysteresis, even for the relatively small changes in length that occur during swimming. We developed a mathematical model comprising three nonlinear springs, two in series with nonlinear dashpots that describe well the tension statics and dynamics for step-stretch experiments. This model suggested that body wall dynamics are slow enough to be neglected when predicting the tension generated by imposed sinusoidal length changes (about +/-10% of nominal) at 1-3 Hz, mimicking swimming. We derived a static model, comprising one nonlinear spring, which predicts sinusoidal data accurately, even when preparations were exposed to serotonin (0.1-10 microM). Preparations bathed in saline-serotonin had significantly reduced steady-state and peak tensions, without alterations in tension dynamics. Anesthetizing preparations (8% ethanol) reduced body wall tension by 77%, indicating that passive tension in the obliquely striated longitudinal muscles of leeches results primarily from a resting tonus.
Flammability Measurements of Difluoromethane

Difluoromethane (CH{sub 2}F{sub 2}, or R-32) is a candidate to replace ozone-depleting chlorofluorocarbon refrigerants. Because CH{sub 2}F{sub 2} is flammable, it is necessary to assess the hazard posed by a leak in a refrigeration machine. The currently accepted method for determining flammability, ASTM E 681 has difficulty discerning the flammability boundary for weak fuels such as CH{sub 2}F{sub 2}. This article describes an alternative approach to identify the limits of flammability, using a twin, premixed counterflow flame. By using the extinction of an already established flame, the point dividing flammable from nonflammable becomes unambiguous. The limiting extinction mixture changes with stretch rate, so it is convenient to report the flammability limit as the value extrapolated to a zero stretch condition. In the burner, contoured nozzles with outlet diameters of 12 mm are aligned counter to each other and spaced 12 mm apart. The lean flammability limit of CH{sub 2}F{sub 2} in dry air at room temperature was previously reported by the authors to be a mole fraction of 0.14, using the twin counterflow flame method. In the current study, relative humidity was not found to affect the lean limit. Increasing the temperature of the premixed fuel and air to 100more » C is shown to extend the flammability limit in the lean direction to 0.13. The rich limit of CH{sub 2}F{sub 2} found using the counterflow method is around 0.27. The uncertainties of the measurements are presented and the results compared to data in the literature.« less
Real-time image mosaicing with a hand-held dual-axes confocal microscope

In recent years there has been growing interest in using confocal microscopy to observe tissue structure and function for in vivo pathology. Although confocal microscopy can provide image resolution that is comparable to histopathology, it can be limited by a small field-of-view as well as a low signal-to-noise ratio. In this paper we show that image mosaicing can enhance confocal microscopy by stitching multiple images together to widen the field-of-view and increase the signal-to-noise ratio. Specifically, we present a real-time image mosaicing system for imaging human skin with a hand-held dual-axes confocal microscope. Our system allows the user to "paint" an image mosaic in real-time and aids navigation by localizing the current view with respect to the larger image map. We first discuss image calibration, then describe an efficient algorithm for real-time image mosaicing, and finally present experimental results obtained in vivo with a dual-axes confocal microscope.
GROWTH HORMONE IN TERMINAL SHOOTS OF NICOTIANA IN RELATION TO LIGHT

THE INFLUENCE of light on plant morphogenesis is becoming more generally recognized as a major problem dealing with the growing points of plants. To influence growing points is to influence the whole course of plant development, because it is at these meristematic centers, these centers of continued embryogeny, that new cells and new organs are constantly being formed. Specific effects of light on meristems are not known, but it is becoming increasingly clear that substances which regulate growth and development are being formed in them, and that these substances subsequently move downward in the axis, influencing cell elongation, development of lateral buds, etc. Hence, any effect of light on the shoot tip is translated into effect on growth and form. While light favors the formation of growth promoting substances in plants, darkness favors their physiological activity (Thimann and Skoog, 1934). Higher concentrations of growth hormone have been found in young illuminated plants than in darkened ones (Navez, 1933; van Overbeek, 1933; Thimann and Skoog, 1934; Avery, 1935; Went, 1935), but the relationship of intensity and quality of light to the hormone content of plants is not yet understood. Studies on the growth depressing effect of light in phototropism and in the normal growth of plants have pointed to various possible explanations of light effects through influence upon movement, lowered activity, or destruction of growth hormones. The purpose of this paper is to present the results of studies on certain effects of darkness and of continuous illumination of varied intensity, duration, and quality upon the growth hormone concentration in terminal shoots of Nicotiana tabacum L. var. Turkish. 'IATERIALS AND METHODS.-Turkish tobacco plants were grown from seed planted in rich soil in flats or in pots in a greenhouse. In a few instances plants were grown also in complete nutrient sand cultures according to the methods previously reported (Avery, Burkholder, and Creighton, 1937b). When the plants had attained suitable size for experimental purposes, they were selected for uniformity and transferred into a special room maintained at 800F. and 90 per cent humidity. In this room light or dark treatment was given as stated in the detailed descriptions of the separate series of experiments. Mazda lamps of 100, 300, or 1000 watts operated at 110 volts A.C. were employed in different numbers and at varied distances from the plants in order to obtain a series of different intensities. In a given experiment only lamps of the same wattage were employed, so that the emission spectra might be comparable. For any one experiment the different intensities were run simultaneously in order to have the
Suppression of Interference due to IQ Modulators in OFDM(A) Based Communication Systems

Multi-carrier modulation techniques, like OFDM, has been gaining significant interest for future wireless communication systems. In spite of all the advantages of OFDM, it has its own challenges. There are several impairments that can degrade the performance of the OFDM systems if the system and transceivers are not designed properly. IQ modulator impairements are among those that can limit the performance significantly. One of the major impacts of the IQ modulator in multiuser OFDM(A) systems (like in WiMAX) is that it introduces interference between the modulated symbols on the image carriers. In this paper, the interference effect caused by IQ modulators will be discussed. Self and multi-access interference caused by the IQ modulators will be explained for multiuser OFDM(A) systems. A joint demodulation based approach to suppress IQ modulator interference will be developed. The performance of the proposed algorithm will be obtained and the performance gains with respect to the conventional receiver will be demonstrated.
A square law for the analysis of real time ellipsometric nucleation and growth data

Abstract Real time ellipsometry has been used to measure critical nucleation parameters, such as the incubation time, nuclei growth rate and nuclei density. Typically, the nuclei geometry is unknown. Therefore, quantitative analysis of real time ellipsometric data is dubious due to the inadequacy of the optical model. In this article we report a novel technique based on a square relationship that exists between nuclei height and volume fraction for a variety of nuclei models. This relationship enables quantitative analysis of real time ellipsometric data for thin film nucleation and growth without a knowledge of the exact nuclei geometry.
Sodium transport in Rana pipiens gastric mucosa.

AbstractThe transport properties of frog gastric mucosa in vitro have been reexamined in conditions analogous to those used in studies on mammalian systems in which net movements of sodium were observed. Net transport of sodium across frog gastric mucosa was not observed to occur when the mucosal surface was bathed with a well-buffered solution of near neutral pH, indicating that failure to demonstrate sodium transport across frog stomach in previous work could not be ascribed to the low pH value of the solution usually used as the mucosal fluid. Addition of 5 × 10-4M amphotericin B to the mucosal solution elicited net transport of sodium and an increase in short-circuit current. These findings indicate that sodium transport may contribute to the electrolyte physiology of frog gastric mucosa in some experimental conditions, and may limit the utility of the three-variable model proposed by Hogben.
A Critique of the Recovery of Greenback Cutthroat Trout

There are no examples of recovery of fish listed under the U.S. Endangered Species Act, but the number of federally threatened greenback cutthroat trout ( Oncorhynchus clarki stomias ) populations is ap- proaching the delisting goal. We evaluated recovery of this subspecies in light of developing theory in conser- vation biology and with regard to recovery of other salmonids in the inland western United States. Four of the five criteria used to define populations that would count toward delisting appeared to underestimate the risk of extinction of those populations. Typically, recovery goals for numbers of greenback cutthroat trout populations were less stringent than those for other inland salmonids petitioned for listing or listed as threat- ened under the Endangered Species Act and were comparable to those for a federally endangered species. Be- fore delisting is considered, we propose that historical populations be replicated in additional waters to pro- tect genetic diversity and that existing populations be enlarged to reduce their vulnerability to demographic variation, to increase their access to refugia, and to permit reestablishment of mobile life histories. Existing stocks should also be evaluated to determine whether they represent distinct population segments.
Mesenchymal hamartoma of the chest wall.

Mesenchymal hamartoma of the chest wall is an unusual lesion remarkable for its occurrence in early infancy and alarming clinical presentation, which often suggests malignancy. Despite its aggressive appearance and propensity to attain massive size, the lesion behaves biologically in a benign fashion, and may be treated conservatively, provided that there is no respiratory compromise secondary to mass effect. The case of an incompletely resected mesenchymal hamartoma that has behaved in a benign fashion after more than 4 years of follow-up is discussed here. We present this case to provide insight and raise clinicians’ awareness of the behavior of an extremely rare tumor.
Terminology for drug injection practices among intravenous drug users in Baltimore.

Terms for four discrete drug injection practices were obtained by presenting photographs and a brief description of practices to intravenous drug users who enrolled in a longitudinal study of HIV infection in Baltimore. The 2,921 respondents were predominately male (81 %) and Black (90%), the median age was 34 years (range: 18-68 years), and the median duration of intravenous drug use was 13 years (range 0-50 years). Forty-six different terms were used to characterize direct injection into a vein, 51 for the practice of repeatedly withdrawing and reinjecting one's own blood following injection of drug, 39 for subcutaneous injection, and 45 for transferring drug between different syringes. Terms tended to cluster by race and duration of drug use. These data indicate substantial variation in terminology for drug injection practices. Further, they augment prior research showing that photographs may be used as a useful aid in survey research on drug experiences in the population.
Local reconstruction for sampling in shift-invariant spaces

The local reconstruction from samples is one of most desirable properties for many applications in signal processing, but it has not been given as much attention. In this paper, we will consider the local reconstruction problem for signals in a shift-invariant space. In particular, we consider finding sampling sets X such that signals in a shift-invariant space can be locally reconstructed from their samples on X. For a locally finite-dimensional shift-invariant space V we show that signals in V can be locally reconstructed from its samples on any sampling set with sufficiently large density. For a shift-invariant space V(ϕ 1, ..., ϕ N ) generated by finitely many compactly supported functions ϕ 1, ..., ϕ N , we characterize all periodic nonuniform sampling sets X such that signals in that shift-invariant space V(ϕ 1, ..., ϕ N ) can be locally reconstructed from the samples taken from X. For a refinable shift-invariant space V(ϕ) generated by a compactly supported refinable function ϕ, we prove that for almost all $(x_0, x_1)\in [0,1]^2$ , any signal in V(ϕ) can be locally reconstructed from its samples from $\{x_0, x_1\}+{\mathbb Z}$ with oversampling rate 2. The proofs of our results on the local sampling and reconstruction in the refinable shift-invariant space V(ϕ) depend heavily on the linear independent shifts of a refinable function on measurable sets with positive Lebesgue measure and the almost ripplet property for a refinable function, which are new and interesting by themselves.
Pineal and adrenal effects on calcium homeostasis in the rat.

ABSTRACT: In human infants and newborn rats, white light at the intensity used to treat hyperbilirubinemia lowers serum calcium concentration. Occipital shielding or (in newborn rats) exogenous melatonin prevents this effect. Propranolol, by inhibiting melatonin synthesis, also causes hypocalcemia, which is preventable by melatonin. Metyrapone or adrenalectomy prevents hypocalcemia after light exposure or propranolol. Exogenous corticosterone lowers serum calcium; this is prevented by supplementary melatonin. In adult rats, the change in calcium after light, propranolol, or corticosterone is minimal. After parathyroidectomy or a diet with a high calcium/low phosphorus ratio, the hypocalcemic effect of these three agents is restored. Bone samples removed after light exposure or corticosterone administration show increased calcium uptake; this is blocked by supplementary melatonin in vivo or by addition of melatonin to the incubation medium. We postulated that the hypocalcemic effect of light or propranolol was due to an acute increase in corticosterone-mediated bone calcium uptake when circulating melatonin was decreased by reduction of the rate of melatonin synthesis. In our study, pinealectomized rats showed no change in serum calcium after light or propranolol; their hypocalcemic response to corticosterone was greater than that of shamoperated controls. Exogenous parathyroid hormone prevented light-induced hypocalcemia in newborn rats.