cssi/SciSciGPT-SciSciNet huggingface dataset:
Development of Biogenic Amines in Yellowfin Tuna (Thunnus albacares): Effect of Storage and Correlation with Decarboxylase‐Positive Bacterial Flora

: The effects of storage at 0,4,10, and 22°C for 0,1,3,5, and 9 d on the quality of yellowfin tuna fillets as determined by microbiological assessment, development of some biogenic amines, and sensory analysis were studied. Tuna fillets stored at 22 °C for 3 d, 10 °C for 5 d, and 4 °C for 9 d were rated unacceptable for consumption. Those stored at 22 °C for 3 d had total aerobic bacterial count of > 8 log10 CFU/g, a histamine-producing bacterial population of 7 log10 CFU/g, and 832 ppm of histamine, 35.8 ppm of putrescine, and 147 ppm of cadaverine. A comparison of the capillary electrophoresis, AOAC fluorometric method, and gas chromatography showed a very good correlation (r2 > 0.99) among these 3 methods for histamine quantitation in tuna samples. Morganella morganii, Enterobacter agglomerans, Enterobacter intermedium, Pseudomonas fluorescens, Proteins vulgaris, and Serratia liquefaciens were the decarboxylase-positive bacterial species isolated by using the Niven's medium and identified during storage, which were responsible for histamine production in test tuna fillets.
β-amyloid from Alzheimer disease brains inhibits sprouting and survival of sympathetic neurons

Abstract The significance of the amyloid plaque core proteins (APCP) in Alzheimer's disease (AD) and its consequences for neuronal survival have been controversial. To address this problem we purified the APCP and βA, obtained from brains with AD, and assessed their biological effects in tissue culture. APCP and βA caused severe toxicity to chick and rat sympathetic and sensory neurons whose survival is dependent upon NGF. This toxicity was dose dependent and reversible at low doses. APCP and βA prevented sprouting of neurites in freshly plated neurons. In established cultures addition of these molecules caused vacuolation and fragmentation of neurites and disintegration of neuronal soma. We suggest that the deposition of APCP in AD may be partly responsible for the destruction of the neuritic arbor, thereby contributing to the formation of the neuritic plaque and to neuronal death.
The P2Y12 Antagonists, 2MeSAMP and Cangrelor, Inhibit Platelet Activation through P2Y12/Gi-Dependent Mechanism

Background ADP is an important physiological agonist that induces integrin activation and platelet aggregation through its receptors P2Y(1) (Gα(q)-coupled) and P2Y(12) (Gα(i)-coupled). P2Y(12) plays a critical role in platelet activation and thrombosis. Adenosine-based P2Y(12) antagonists, 2-methylthioadenosine 5'-monophosphate triethylammonium salt hydrate (2MeSAMP) and Cangrelor (AR-C69931MX) have been widely used to demonstrate the role of P2Y(12) in platelet function. Cangrelor is being evaluated in clinical trials of thrombotic diseases. However, a recent study reported that both 2MeSAMP and Cangrelor raise intra-platelet cAMP levels and inhibit platelet aggregation through a P2Y(12)-independent mechanism. Methodology/principal findings The present work, using P2Y(12) deficient mice, sought to clarify previous conflicting reports and to elucidate the mechanisms by which 2MeSAMP and Cangrelor inhibit platelet activation and thrombosis. 2MeSAMP and Cangrelor inhibited aggregation and ATP release of wild-type but not P2Y(12) deficient platelets. 2MeSAMP and Cangrelor neither raised intracellular cAMP concentrations nor induced phosphorylation of vasodilator-stimulated phosphoprotein (VASP) in washed human or mouse platelets. Furthermore, unlike the activators (PGI(2) and forskolin) of the cAMP pathway, 2MeSAMP and Cangrelor failed to inhibit Ca(2+) mobilization, Akt phosphorylation, and Rap1b activation in P2Y(12) deficient platelets. Importantly, while injection of Cangrelor inhibited thrombus formation in a FeCl(3)-induced thrombosis model in wild-type mice, it failed to affect thrombus formation in P2Y(12) deficient mice. Conclusions These data together demonstrate that 2MeSAMP and Cangrelor inhibit platelet function through the P2Y(12)-dependent mechanism both in vitro and in vivo.
Determination of aggregation force in rouleaux by fluid mechanical technique.

Abstract The shear stress needed to disaggregate red cell rouleaux was quantified in a flow channel under microscopic observation. Measurement were made on two-cell rouleaux formed in 4g% dextran with a mean molecular weight of 74,500. Stepwise increases in shear stress caused a progressive peeling of the top cell of the rouleau, and the percentage of separation as estimated from the exposed area of the bottom cell showed a sigmoidal relation with shear stress. The 50% separation occurred at a shear stress of 0.25 ± 0.01 dyn/cm2 (mean ± SEM), which is approximately one-half of the value obtained in rotational measurements on bulk suspensions where the orientation of red cells is more random. This technique of studying stress-disaggregation relationships in a flow channel has the advantages that (a) the applied shear stress is parallel to the rouleau interface and (b) the degree and process of disaggregation can be followed directly by microscopic observation.
Deuterium Isotope Effects on Reaction Rates of Ground State Zr with Ethylene and Propylene

Kinetic isotope effects for the reactions of Zr (4d 2 5s 2 , 3 F) with C2H4 and C2D4 and with C3H6 and C3D6 are measured in a fast flow reactor at 300 K with He/N2 buffer gas at 0.8 Torr. The H2 and D2 elimination products are detected using single photon ionization at 157 nm and time-of-flight mass spectrometry. We find no significant isotope effect for reaction with either ethylene or propylene. These results clearly favor an indirect mechanism involving addition of the metal atom to the CC double bond and subsequent CH insertion and rule out a recently proposed mechanism involving direct CH bond insertion at low collision energy. Density functional theory in its B3LYP/LANL2DZ form finds no barrier to addition of ground state Zr to the double bond of ethylene and confirms the existence of a low-energy path from the metallacyclopropane complex to H2 products. Theory also provides a realistic set of geometries and vibrational frequencies for use in a statistical rate model of the hot metallacyclopropane complex decay. However, the RRKM calculations indicate that a small barrier (0.5-2 kcal/mol) to the approach of Zr and ethylene is necessary to explain our kinetics data and the crossed beam angular distributions of Willis et al. In addition, the barrier to CH insertion must be lowered by 3-6 kcal/mol from the B3LYP/LANL2DZ value.
Behavior analysis and intervention during hospitalization for brain trauma rehabilitation

Abstract Continued problematic behavior in children and adolescents after brain trauma is a major barrier to medical care, rehabilitation, and eventual independent living. The present study demonstrates the application of already well-developed behavior analysis techniques to the early posttrauma expression of behavior problems during hospital recovery. To satisfy concerns regarding both cost and individualized treatment, interventions were carried out primarily by regular hospital staff (nurses and therapists), medical record data were used to document gains, and time series, within subject designs were used to show experimental control. Four patients (three male and one female) ranging in age from 10 to 16 years, received intervention based on behavior analysis techniques, which reduced disruption and increased cooperation with therapy and medical care. Behavior analysis techniques will be relevant to future rehabilitation research to the extent that the posttrauma patient's behavior is effected by environmental consequences as demonstrated here.
Passwords in use in a university timesharing environment

0 n Thursday morning, November 3, 1988, the national news reported that a computer virus had shut down a nationwide computer network, Internet. The virus, actually a worm program, took advantage of “flaws in utility programs in systems based on BSD-derived versions of Unix.” uThe flaws allowed the program to break into those machines and copy itself, thus infecting those systems,” cvcntually spreading to thousands of machines and halting normal network activity [ 111. One part of the worm program attempted to break user passwords using a mini-dictionary of 432 words it contained [l 11. This list, only a part of the program, raised several important questions: Where did the list come from? How was it created? Is the list representative of passwords found on other computers. ) We cannot answer the first two questions, but we can provide possible answers to the last.
Vascular risk in migraineurs: interaction of endothelial and cortical excitability factors.

Background Migraine is a common primary headache disorder occurring predominantly in a young, relatively healthy population. Results There is a growing literature on associations between migraine, especially migraine with aura, and ischemic stroke as well as other vascular events. Migraine as a risk factor for vascular disease and connections between migraine and endothelial, structural, and genetic risk are reviewed. Conclusion There may be an interaction between endothelial dysfunction and cortical spreading depression affecting risk. Patient education and treatment of modifiable risk factors may decrease future vascular events.
A unified approach to the effects of symmetry and periodicity on boundary-value problems

A generalized approach to the effects of symmetry and periodicity on boundary-value problems is presented, especially as it pertains to the guiding structures encountered in electromagnetics. Several examples of structures and their dispersion behavior are given, and the theory predicts well that other authors claim.
Massive ovarian edema associated with ovarian serous cystadenoma: a case report and review of the literature

Massive ovarian edema is a rare entity that can be confused with an ovarian neoplasm. A few ovarian lesions have been reported that are associated with massive ovarian edema. This article describes the first case of an ovarian serous cystadenoma associated with a massive ovarian edema. The patient was a 17-year-old female who was referred to the emergency room because of lower abdominal pain. Subsequent ultrasound and computed tomography scanning studies revealed an abdominopelvic cystic mass suggestive of an ovarian neoplasm. She underwent an exploratory laparoscopy, and a left salpingo-oophorectomy was performed. The specimen weighed 1610 g and consisted of a cystic mass measuring 17 x 15 x 8 cm attached to a solid mass measuring 13 x 11 x 4 cm. Microscopy revealed a cystic and a solid lesion. The cystic structure was composed of a flat or cuboidal single-layer lining showing ciliated epithelium and focal areas of papillary structures compatible with a diagnosis of ovarian serous cystadenoma. The solid mass had an intact capsule and diffuse interstitial edema, preserving the overall structure of the ovary and sparing the outer cortex. These findings are compatible with the diagnosis of ovarian massive edema. This report of an association of serous cystadenoma with massive ovarian edema broadens the histologic spectrum in which a massive ovarian edema may be encountered.
Nuclear photoactivation cross sections for short-lived isomeric states excited with a 6 MeV linac

Photoactivation cross sections for short-lived (T12 < 20 s) isomeric states in 167Er, 79Br, 191Ir, 183W, 197Au, 77Se, 137Ba and 89Y were determined using bremsstrahlung from a 6 MeV medical therapy linac. A portable NaI(Tl) spectrometer and pneumatic transfer system was designed to avoid impacting normal use of the linac. Comparison with data obtained at the PITHON flash X-ray source (1.5 MeV endpoint energy) indicates that cross sections for populating these isomers through gateway states in the range 1.5–6 MeV are more than three orders of magnitude greater than corresponding cross sections below 1.5 MeV. The results are significant for the development of photoactivation techniques to measure short (<100 ns), nonreproducible bremsstrahlung pulses.
Intraflagellar transport motors in cilia: moving along the cell's antenna

Intraflagellar transport (IFT), the motor-dependent movement of IFT particles along the axoneme, is critical for the assembly, maintenance, and function of motile and sensory cilia, and, consequently, this process underlies ciliary motility, cilium-based signaling, and ciliopathies. Here, I present my perspective on IFT as a model system for studying motor-driven cargo transport. I review evidence that kinesin-2 motors physically transport IFT particles as cargo and hypothesize that several accessory kinesins confer cilia-specific functions by augmenting the action of the two core IFT motors, kinesin-2 and dynein 1b, which assemble the cilium foundation.
Powerful, Multifunctional Torsional Micromuscles Activated by Phase Transition

Micro bimorph coils driven by a metalinsulator phase transition in VO2 function as powerful torsional muscles. Reversible torsional motion over one million cycles without degradation is demonstrated, with a superior rotational speed up to ca. 200,000 rpm, an amplitude of 500° per mm length, and a power density up to ca. 39 kW kg⁻¹.
Impaired host odor perception in hybrids between the sibling species Rhagoletis pomonella and R. mendax

Rhagoletis pomonella, living on apple, and R. mendax, infesting blueberry, represent a closely related sibling species pair with very limited morphological differentiation. Allozyme studies indicate that these species coexist with no detectable gene flow in areas where both hosts occur in close sympatry (Feder et al., 1989). However, viable interspecific F1, F2 and back-cross progeny can be easily produced in the laboratory (Bush, 1966). Therefore, premating isolating barriers must exist that restrict hybridization between these sibling species in nature.
Work schedule, sleep duration, insomnia, and risk of fatal prostate cancer.

Background Studies of breast cancer in women and laboratory studies provide evidence that shift work involving circadian rhythm disruption is a probable human carcinogen. However, evidence linking shift work and other circadian disruption factors to prostate cancer risk is limited. Purpose To examine associations of work schedule (i.e., rotating shift work, fixed night and fixed afternoon/evening shift work); sleep duration; and insomnia frequency with prostate cancer mortality. Methods The Cancer Prevention Study–II is a large prospective cohort study of U.S. adults. Work schedule, sleep duration, insomnia frequency, and other information was self-reported in 1982. Among 305,057 employed men, aged ≥29 years who were cancer free at baseline, there were 4974 prostate cancer deaths during follow-up through 2010. In 2013, multivariable-adjusted relative risks (RRs) and 95% CIs were computed using Cox proportional hazards regression. Results Work schedule and insomnia frequency were not associated with risk of fatal prostate cancer. Short sleep duration was associated with higher risk of prostate cancer during the first 8 years of follow-up, compared to 7 hours/night, the RRs (95% CIs) for 3–5 and 6 hours/night were 1.64 (1.06, 2.54), and 1.28 (0.98, 1.67), respectively. There was no association between sleep duration and fatal prostate cancer during later follow-up. Conclusions These results do not support associations of work schedule or insomnia frequency with prostate cancer mortality. The association between short sleep duration and higher risk of fatal prostate cancer only during the first 8 years of follow-up suggests that short sleep duration could affect later stages of prostate carcinogenesis.
Semantic Technology and the Question-Centric Curriculum

In this article I describe software that facilitates “question-centric curricula” in which big questions, rather than academic disciplines, are the primary means of organizing educational resources. To find these questions, the software scans course catalogs and extracts all sentences ending in a question mark. To find connections between questions and courses, I present several computational techniques. One leverages the Library of Congress system; another implements so-called semantic technology that uses huge numbers of simple internet searches to ascertain the meaning of texts. The software assembles the results and shows, in one image, how every course at an institution relates to a given question.
Lake restoration by biomanipulation: Round Lake, Minnesota, the first two years

SUMMARY. 1. Rotenone was applied to Round Lake in the autumn of 1980 in order to eliminate predominantly planktivorous and benthivorous fish. The lake was subsequently restocked with a higher population density of piscivores. The effect of this biomanipulation on the phytoplankton and zooplankton communities and on total nutrient concentrations was monitored at fortnightly intervals during the summers, from May 1980 to September 1982. 2. The abundance of phytoplankton was much lower after biomanipulation and was consistent with observed changes in Secchi disc transparency, total attenuation coefficient and chlorophyll a concentration. Zooplankters were also less abundant in 1981 and 1982 but the decrease in numbers was more than offset by the large increase in the mean sizes of the zooplankters present, so that the estimated grazing pressures in 1981 and 1982 were at least double the 1980 value. 3. Daphnia, rare in 1980, became the dominant genus in 1981 and 1982, and a shift to progressively larger-bodied Daphnia species was observed. 4. Although total nitrogen and total phosphorus levels were generally lower after biomanipulation, their decline could not explain the reduction in phytoplankton abundance which was attributed to the increased grazing pressure. Possible causes of the observed declines in nutrient concentrations are discussed.
Advanced signal processing for passive infrared remote sensing

AbstractPassive remote sensing addresses the problem of remotely monitoring, i.e. detecting thepresence of, specific chemicals by the analysis of the radiative infrared signature of thematerial in the line -of -sight (LOS). Development of processing techniques for detectingthe presence of the target chemical with a low enough false alarm rate in real time is theessence of the signal processing requirement for remote sensing. The aspects of datasimulation and signal processing to achieve the passive remote monitoring objective arediscussed. Application to environmental pollution monitoring is suggested.IntroductionThe passive radiative signal received by a sensor is a combination of emission,absorption, and scattering of energy by all the materials in the LOS. Figure 1illustrates a typical scenario with a chemical cloud in the LOS. The spectral signalreceived by the sensor depends on the background energy, the transfer characteristics ofthe medium and the absorptivity coefficients of the material. Assuming, for the sake ofsimplicity, that the background energy is black body radiation corresponding to theambient termperature and that the foreground attention of the signal is negligible thespectral signal received at the sensor is given byNs = Ngbdy(target) + T [Ngbdy(background)-Ngbdy(target)]
The sodium order-disorder transition on the NaxWO3 (100) single crystal surface

Abstract An order-disorder transition involving mobile sodium on the (100) surface of single crystal Na x WO 3 has been observed using low energy electron diffraction. The kinetics of this transition have been investigated by following the intensity and size of diffraction features associated with ordered sodium on the surface. The activation energy for diffusion of sodium on the (100) surface of Na x WO 3 is determined to be 4 kcal/mole.
Relationships between norepinephrine and cyclic nucleotides in brain and seizure activity

To characterize further the roles of norepinephrine (NE) and cyclic nucleotides in seizure mechanisms, an examination was made of the effects of several drugs purported to depress noradrenergic influence in the CNS on pentylenetetrazol-induced seizure activity and regulation of cyclic AMP levels in the cerebral cortex and hippocampus in mice. Depletion of brain stores of NE with reserpine or treatment of neonatal mice with 6-hydroxy-dopamine decreased seizure latency and/or threshold and diminished seizure-induced accumulation of cyclic AMP in brain. Propranolol, a β-adrenergic receptor antagonist, and yohimbine, an α2-adrenergic receptor antagonist, had effects qualitatively similar to reserpine and 6-hydroxy-dopamine, but phentolamine, a mixed α-adrenergic antagonist, increased seizure threshold and latency and did not reduce the accumulation of cyclic AMP. None of the drugs tested had any consistent effect on the regulation of cyclic GMP levels in brain during seizures. These data are consistent with the hypothesis that cyclic AMP in brain may be mediating an inhibitory influence of NE on seizure activity.
Calcium Exchange in the Alveolar Process of Dogs as Influenced by Light Continuous and Heavy Intermittent Orthodontic Forces

A quantitative autoradiographic technic was used to measure 45Ca activity in the tension and pressure regions of dog teeth subjected to light continuous or heavy intermittent forces. Significant differences were observed betwee these regions.
Biosynthesis and exchange experiments on some plant pigments using Mg28 and C14.

Abstract Radioactive Mg has been incorporated into chlorophylls in growing algae, most probably by biosynthesis. Pure chlorophylls a and b appear not to exchange or associate Mg 28++ in vitro , either when separated or mixed . Minimum half-times of exchange are given. Radioactive carbon has been incorporated in carotene, xanthophylls, and chlorophylls a and b. The ratios of C 14 activity and Mg 28 activity in chlorophylls a and b are the same within experimental error. Translocation of Mg 28++ in the coleus plant was studied.
Onset of expression of the alpha subunit of Ca2+/calmodulin-dependent protein kinase II and a novel related protein in the developing retina

Calcium-calmodulin-dependent protein kinase II is an abundant protein in the nervous system and has been associated with many aspects of neuronal function, including events related to synaptic transmission. The purpose of this study is to correlate the onset of expression of this kinase with a specific developmental event in retinal morphogenesis using a monoclonal antibody to the 50-kDa alpha-subunit. Microscopy showed the antigen to be associated with the plexiform layers of the retina. Western blots demonstrated that the onset of expression of the alpha-subunit coincided in time with the initial formation of the plexiform layers. However, the onset of expression of the 50-kDa alpha-subunit was preceded by the earlier embryonic appearance of a related 82.5-kDa antigen that was recognized by the antibody. The amount of this latter protein declined as the amount of the alpha-subunit increased in retinal homogenates. Although this related 82.5 kDa protein disappeared from blots of retinal homogenates after embryonic d 14, it could be detected in concentrated supernatant fractions isolated from the retinae of hatched chicks. Microscopy showed that a subset of retinal cells and their processes contained this antigen in early embryonic chicks. Finally, the 50 kDa alpha-subunit of kinase II and the 82.5 kDa novel antigen were shown to be separable by differential centrifugation.
A mechanism of dimethylsulfoxide protection against the teratogenicity of secalonic acid D in mice

Dimethylsulfoxide (DMSO) is known to antagonize the teratogenic effects of secalonic acid D (SAD) in mice. To establish the optimum protective dose of DMSO, pregnant CD-1 mice were treated, i.p., with 30 mg/kg of SAD in 5% (w/v) NaHCO3, containing 0, 10, 20, or 30% (v/v) DMSO on day 11 of gestation. Data indicate that at 10% and 20% levels, DMSO affords an apparent dose-related protection against SAD-induced cleft palate, whereas 30% DMSO enhanced fetal resorption with no reduction in the incidence of cleft palate. Ultraviolet spectra and TLC mobility indicated that DMSO at 20% did not directly interact with SAD. Distribution and elimination of 14C-SAD was studied in fetal and maternal tissues from pregnant mice at 24 and 48 hr after exposure to 30 mg/kg of 14C-SAD, i.p., in NaHCO3 (control) or in 20% DMSO. Compared with those not receiving DMSO, maternal exposure to DMSO: (1) significantly reduced (42–75%) radioactivity in fetal heads and bodies, placenta, and maternal tissues other than liver; (2) significantly increased (up to 222%) the radioactivity in maternal liver; and (3) significantly reduced (44–58%) fecal and urinary elimination of SAD-derived radioactivity. These results suggest that the antiteratogenic effect of DMSO against SAD may be at least partly mediated by increased SAD (or its metabolites) retention by maternal liver leading to reduced SAD uptake by the fetus.
THE FORMATION OF A COMMERCIAL LOBBY: THE WEST INDIA INTEREST, BRITISH COLONIAL POLICY AND THE AMERICAN REVOLUTION

British colonial policy initiatives of the 1760s and the American revolutionary war led to a period of sustained lobbying by the West India interest in Britain; lobbying which developed from an informal body into a more professionally organized lobby, along the lines of modern economic interest groups. The composition of the lobby and its activities during the revolutionary period are examined here. Its considerable influence is also assessed and explained. The article finds that the lobby won major concessions from the British government and vitally affected British policy towards North America. It nevertheless concludes that the lobby enjoyed its greatest influence in the early century when ironically its organization was weaker but its goals coincided more harmoniously with those of British colonial policy. Its later reorganization was a response to the increasing conflicts of interest between the white elites of the British Caribbean and the mother country which intensified during the period of the American revolution and its aftermath.
The Relationship of Body Composition, Feed Intake, and Metabolic Hormones for Broiler Breeder Females

Abstract Three hundred twenty Cobb 500 broiler breeder pullets at 21 wk of age were selected from a flock fed according to Cobb Breeder Management Guide specifications. One hundred sixty pullets at 21 wk of age were switched to ad libitum feeding, and the remaining 160 pullets continued to be control-fed. The pullets were photostimulated at 22 wk and maintained until 36.5 wk. Plasma samples were obtained, BW was determined, and hens were killed for determination of body composition at the following periods: 24 h prior to photostimulation, 2.5 wk after photostimulation, 24 h after first egg, and 36.5 wk following peak egg production. Compared with ad libitum-fed breeders, the restricted breeders had a higher percentage carcass protein and lower percentage carcass fat at all sampling periods. Total egg numbers were greater, and abnormal eggs were less for the restricted pullets compared with the ad libitum-fed pullets at 36.5 wk. Carcass percentage fat of ad libitum-fed pullets was positively related to plasma glucagon, insulin-like growth factor-II (IGF-II), and 17β-estradiol but negatively related to plasma insulin, insulin/glucagon M ratio, insulin-like growth factor-I (IGF-I), thyroxine (T4), and triiodothyronine (T3). Carcass percentage fat of feed-restricted pullets was negatively related to IGF-I, IGF-II, and T4. The T4 was the most important hormone for predicting the percentage carcass fat in ad libitum-fed pullets, and IGF-I was the most important hormone for predicting the percentage carcass fat in feed-restricted pullets. The percentage carcass protein for ad libitum-fed breeders was positively correlated to IGF-I, T4, T3, insulin/glucagon M ratio, and insulin. Carcass percentage protein for feed-restricted breeders was positively correlated to IGF-I, IGF-II, T4, and glucagon. Stepwise regressions for predicting percentage carcass protein for breeders fed by both systems shows that T3 and IGF-I concentrations were the most important for ad libitum-fed breeders, whereas IGF-II and T4 were best for feed-restricted breeders. The hormone status of breeders may be a key indicator to help predict the body composition and thus support management decisions for maintaining optimum production.
Science and technology of ceramic foams

This paper reviews aspects of the science and technology of ceramic foams, a class of technologically important materials. In spite of the long history of ceramic foam use in industry, the understanding of their mechanical properties is of recent origin. The review begins with a general discussion of foam-like porous materials leading to the physical properties of ceramic foams. The mechanical properties are then presented. Several alternate processing methods are shown. The paper ends with a review of potential uses, both present and future.
Characterization of scatter in digital mammography from use of Monte Carlo simulations and comparison to physical measurements.

Purpose: Monte Carlo simulations were performed with the goal of verifying previously published physical measurements characterizing scatter as a function of apparent thickness. A secondary goal was to provide a way of determining what effect tissue glandularity might have on the scatter characteristics of breast tissue. The overall reason for characterizing mammography scatter in this research is the application of these data to an image processing-based scatter-correction program. Methods: MCNPX was used to simulate scatter from an infinitesimal pencil beam using typical mammography geometries and techniques. The spreading of the pencil beam was characterized by two parameters: mean radial extent (MRE) and scatter fraction (SF). The SF and MRE were found as functions of target, filter, tube potential, phantom thickness, and the presence or absence of a grid. The SF was determined by separating scatter and primary by the angle of incidence on the detector, then finding the ratio of the measured scatter to the total number of detected events. The accuracy of the MRE was determined by placing ring-shaped tallies around the impulse and fitting those data to the point-spread function (PSF) equation using the value for MRE derived from the physical measurements. The goodness-of-fit was determined for each data set as a means of assessing the accuracy of the physical MRE data. The effect of breast glandularity on the SF, MRE, and apparent tissue thickness was also considered for a limited number of techniques. Results: The agreement between the physical measurements and the results of the Monte Carlo simulations was assessed. With a grid, the SFs ranged from 0.065 to 0.089, with absolute differences between the measured and simulated SFs averaging 0.02. Without a grid, the range was 0.28–0.51, with absolute differences averaging −0.01. The goodness-of-fit values comparing the Monte Carlo data to the PSF from the physical measurements ranged from 0.96 to 1.00 with a grid and 0.65 to 0.86 without a grid. Analysis of the data suggested that the nongrid data could be better described by a biexponential function than the single exponential used here. The simulations assessing the effect of breast composition on SF and MRE showed only a slight impact on these quantities. When compared to a mix of 50% glandular/50% adipose tissue, the impact of substituting adipose or glandular breast compositions on the apparent thickness of the tissue was about 5%. Conclusions: The findings show agreement between the physical measurements published previously and the Monte Carlo simulations presented here; the resulting data can therefore be used more confidently for an application such as image processing-based scatter correction. The findings also suggest that breast composition does not have a major impact on the scatter characteristics of breast tissue. Application of the scatter data to the development of a scatter-correction software program can be simplified by ignoring the variations in density among breast tissues.
Surface analysis by laser desorption of neutral molecules with detection by fourier-transform mass spectrometry

Abstract Molecules chemisorbed on a platinum single crystal are desorbed by a pulsed laser, ionized by an electron beam or multiphoton ionization, and detected by Fourier-transform mass spectrometry (F.t.m.s.). Laser desorption of ethylene, methanol, cyanogen, benzene and naphthalene is described. In all cases, molecular ions are the major peaks observed in the mass spectra, and the minor peaks correspond to known electron-impact fragments of the adsorbates. For the systems investigated thus far, the laser-desorption F.t. mass spectra are less complex and esier to interpret than the spectra produced by secondary-ion mass spectrometry, which are complicated by the rapid ion/-molecule reactions that can occur directly above the surface between adsorbates and substrate atoms. In the laser-desorption method, these complications are avoided because the ions are formed after the desorbed molecules have moved away from the surface and have expanded into the vacuum. The sensitivity of the laser-desorption F.t.m.s. method is tested. For carbon monoxide adsorbed on platinum, the detection limit is ca. 5 × 10−6 monolayer per cm2. For naphthalene, a single laser pulse at 248 nm produces abundant molecular ions even when the electron beam is turned off. The ions appear to be produced by resonance-enhanced multiphoton ionization rather than a thermal process. In these experiments, multiphoton ionization of naphthalene at 248 nm is about 35-fold more sensitive than electron ionization.
Oxidation of aromatic contaminants coupled to microbial iron reduction

THE contamination of sub-surface water supplies with aromatic compounds is a significant environmental concern1,2. As these contaminated sub-surface environments are generally anaerobic, the microbial oxidation of aromatic compounds coupled to nitrate reduction, sulphate reduction and methane production has been studied intensively1–7. In addition, geochemical evidence suggests that Fe(III) can be an important electron acceptor for the oxidation of aromatic compounds in anaerobic groundwater. Until now, only abiological mechanisms for the oxidation of aromatic compounds with Fe(III) have been reported8–12. Here we show that in aquatic sediments, microbial activity is necessary for the oxidation of model aromatic compounds coupled to Fe(III) reduction. Furthermore, a pure culture of the Fe(III)-reducing bacterium GS-15 can obtain energy for growth by oxidizing benzoate, toluene, phenol or p-cresol with Fe(III) as the sole electron acceptor. These results extend the known physiological capabilities of Fe(III)-reducing organisms and provide the first example of an organism of any type which can oxidize an aromatic hydrocarbon anaerobically.
Automated detection of pulmonary nodules from whole lung helical CT scans: performance comparison for isolated and attached nodules

The objective of this research is to evaluate and compare the performance of our automated detection algorithm on isolated and attached nodules in whole lung CT scans. Isolated nodules are surrounded by the lung parenchyma with no attachment to large solid structures such as the chest wall or mediastinum surface, while attached nodules are adjacent to these structures. The detection algorithm involves three major stages. First, the region of the image space where pulmonary nodules are to be found is identified. This involves segmenting the lung region and generating the pleural surface. In the second stage, which is the hypothesis generation stage, nodule candidate locations are identified and their sizes are estimated. The nodule candidates are successively refined in the third stage a sequence of filters of increasing complexity. The algorithm was tested on a dataset containing 250 low-dose whole lung CT scans with 2.5mm slice thickness. A scan is composed of images covering the whole lung region for a single person. The dataset was partitioned into 200 and 50 scans for training and testing the algorithm. Only solid nodules were considered in this study. Experienced chest radiologists identified a total of 447 solid nodules. 345 and 102 of the nodules were from the training and testing datasets respectively. 126(28.2%) of the nodules in the dataset were attached nodules. The detection performance was then evaluated separately for isolated and attached nodule types considering different size ranges. For nodules 3mm and larger, the algorithm achieved a sensitivity of 97.8% with 2.0 false positives (FPs) per scan and 95.7% with 19.3 FPs per scan for isolated and attached nodules respectively. For nodules 4mm and larger, a sensitivity of 96.6% with 1.5 FP per scan and a 100% sensitivity with 13 FPs per scan were obtained for isolated and attached nodule types respectively. The results show that our algorithm detects isolated and attached nodules with comparable sensitivity but differing number of false positives per scan. The high number of false positives for attached nodule detection was mainly due to the complexity of the mediastinum lung surface.
An exceptional amino acid replacement on the distal side of the iron atom in proboscidean myoglobin

Amino acid sequence determination of elephant myoglobin revealed the presence of the unusual substitution E7 His → Gln. Stereochemical analyses suggest that the most suitable residue which can functionally substitute for His at this position in vertebrate globins is Gln. Physiochemical studies imply that the slower rate of autooxidation of elephant myoglobin is the result of this substitution which may confer some selective advantage on the species. Comparative sequence data of paenungulate myoglobins suggest that the His → Gln mutation probably occurred in an ancestor of Elephantinae.
Three-dimensional vector graphics: a method for displaying results in a drug trial.

Abstract Three-dimensional computer graphics are used to depict multidimensional outcome measures in a clinical drug trial. This graphics approach was used in a study of 116 patients with active rheumatoid arthritis, in a randomized, double-blind 21-week comparison of placebo, oral gold, and injectable gold. Three health status components, physical disability, psychological status, and pain, were generated using the Arthritis Impact Measurement Scales (AIMS). Results were presented in a three-axis perspective, one axis for each component, plotting individual patient vectors for magnitude and direction on a 10 × 10 × 10 coordinate matrix. Vectors for each patient are plotted from time 1 (start) to time 2 (finish) over the 21-week trial period. Vector symbols were added for clarity and subgroup delineation. Vector displays show trends in treatment response that clarify and strongly reinforce the statistical results. It is concluded that three-dimensional vector graphics are a useful adjunct to the statistical analysis of clinical trial results. The graphics facilitate the visual interpretation of a complex data set, and clarify the analysis of the results for both the clinician and researcher.
Library policy structure: an industrial dynamics study

An industrial dynamics model of a university library, developed originally to investigate the effect of library control policies, is described. The model is used to analyze the effect of two policies pro posed by the Physics Library at Purdue University. After having operated under extremely crowded con ditions for the past several years, the Physics Library will move in 1971 into new, more spacious quarters. The policies for loans from the library collection have been rather free, control over the collection has been lax, and penalties for users failing to comply with library policies have been mild. The reasoning behind these policies was that if all loaned materials were returned, sufficient shelf space was unavailable.With the space limitations removed in the new quarters, the Physics Librarian can adopt one of two general policies:Policy 1 - Closer control over the library collection, more restrictive loan policies, more staff, and longer operating hoursPolicy 2 - Less control over the collection wit...
1-D Infinite Array of Metalloporphyrin Cages

The reaction of Co(II) with 5,15-dipyridyl-10,20-diphenylporphyrin (H2DPyP) produces the first metal-organic coordination polymer supported by a trans meso-bifunctional porphyrin ligand. Formulated empirically as [Co3(DPyP)3]·4DMF, this compound exhibits a ribbonlike coordination network consisting of tetranuclear metalloporphyrin cages. The DMF guest molecules fill the intra-ribbon cages as well as the inter-ribbon space. Evacuation of [Co3(DPyP)3]·4DMF at 130 °C generates [Co3(DPyP)3] that retains crystallinity, as shown by its powder X-ray diffraction pattern, which is consistent with that of [Co3(DPyP)3]·4DMF.
Catecholamine metabolic pathways and exercise training. Plasma and urine catecholamines, metabolic enzymes, and chromogranin-A.

BACKGROUNDBecause acute exercise increases systemic catecholamines, we sought to determine whether exercise training would alter daily or exercise-related catecholamine release and inactivation.METHODS AND RESULTSIn 24-hour urine collections, catecholamines and metabolites provided indexes of overall oxidative deamination, sulfation, and O-methylation. Plasma catecholamines, the sulfoconjugates of each, and chromogranin-A were determined at rest and during exercise in 10 well-trained male subjects and nine minimally trained male subjects (maximal oxygen uptake 55.2 and 42.5 ml/kg/min, respectively), and levels of activities of catechol-O-methyltransferase (COMT), monoamine oxidase B (MAO-B), and thermolabile phenolsulfotransferase (TL-PST) were also determined. Plasma-free catecholamines showed minimal differences between the two groups at submaximal exercise (4 minutes) but large differences at maximal exercise, reflecting the different exercise levels attained. Inactivation of plasma catecholamines by s...
The Cost of Client Transfer

Clients undergoing transfer from one counselor to another were compared on the Generalized Contentment Scale and a DSM-III-R measure with clients staying with the same counselor over the same length of treatment. In three 12-week blocks, the clients with the same counselor made the greatest progress in the first 12 weeks, making less progress in each successive block. The clients who were transferred in the middle of the second 12-week block also made the greatest progress in the first time block, lost some of the progress in the transfer block, and made significant progress with the new counselor in the third time block, ending with no significant differences in either generalized contentment or DSM-III-R outcome from clients who had not been transferred.
Integrated Control Techniques for Advanced Aircraft Electrical Power Systems

Advanced control techniques for aircraft electrical power distribution systems are discussed. These advanced distribution systems combine solid-state power switching with computer control to provide automated control, adaptive load management, self-test, operational flexibility, and fault-tolerant performance. Lower-cost electrical systems for small aircraft can be achieved by integrating the electrical system control functions with an aircraft integrated avionics system. Cost savings in hardware and software development and maintenance may offset the disadvantages associated with the use of standard processors and higher levels of subsystem integration. Several integration techniques that have potential are now being studied and are discussed in this paper.
Existence and Stability of Multidimensional Transonic Flows through an Infinite Nozzle of Arbitrary Cross-Sections

We establish the existence and stability of multidimensional steady transonic flows with transonic shocks through an infinite nozzle of arbitrary cross-sections, including a slowly varying de Laval nozzle. The transonic flow is governed by the inviscid potential flow equation with supersonic upstream flow at the entrance, uniform subsonic downstream flow at the exit at infinity, and the slip boundary condition on the nozzle boundary. Our results indicate that, if the supersonic upstream flow at the entrance is sufficiently close to a uniform flow, there exists a solution that consists of a C1,α subsonic flow in the unbounded downstream region, converging to a uniform velocity state at infinity, and a C1,α multidimensional transonic shock separating the subsonic flow from the supersonic upstream flow; the uniform velocity state at the exit at infinity in the downstream direction is uniquely determined by the supersonic upstream flow; and the shock is orthogonal to the nozzle boundary at every point of their intersection. In order to construct such a transonic flow, we reformulate the multidimensional transonic nozzle problem into a free boundary problem for the subsonic phase, in which the equation is elliptic and the free boundary is a transonic shock. The free boundary conditions are determined by the Rankine–Hugoniot conditions along the shock. We further develop a nonlinear iteration approach and employ its advantages to deal with such a free boundary problem in the unbounded domain. We also prove that the transonic flow with a transonic shock is unique and stable with respect to the nozzle boundary and the smooth supersonic upstream flow at the entrance.
Re-epithelialization of the rat cornea is accelerated by blockade of opioid receptors.

Abstract A native opioid peptide, [Met 5 ]-enkephalin, termed opioid growth factor (OGF), serves as a constitutively expressed and autocrine produced inhibitory molecule related to developing, neoplastic, renewing, and healing tissues. The present study was designed to examine the effects of interfering with opioid–receptor interaction during re-epithelialization of the cornea in the rat using both systemic injections and topical applications of the potent opioid antagonist naltrexone (NTX). A 4 mm diameter epithelial defect was made in the center of the rat cornea. NTX injected twice daily or applied as eyedrops four times daily significantly accelerated re-epithelialization compared to controls. Beginning as early as 8 h after wounding, both the systemic and topical NTX treatment groups had defects that were approximately 10% to 67% smaller than control abrasions at the time points examined. Similarly, the rate of healing for the NTX groups was 4.7- and 2.8-fold greater than controls for systemic and topical paradigms, respectively. The incidence of complete re-epithelialization in animals given systemic administration of NTX was markedly accelerated in comparison to control rats; however, differences in incidence of repair between NTX and control groups receiving topical application were not observed. These results show that native opioid peptides function in wound healing, and exert a tonically inhibitory influence at the receptor level on repair of corneal epithelial injuries.