cssi/SciSciGPT-SciSciNet huggingface dataset:
MOLECULAR DYNAMICS SIMULATIONS OF NON-NEWTONIAN EXTENSIONAL FLUID FLOWS

We discuss the use of molecular dynamics computer simulations in the extensional flow dynamics of polymeric, non-Newtonian liquids. The molecular model consists of Lennard-Jones monomers bound into linear chains by FENE potentials, a system known to exhibit characteristic non-Newtonian behavior such as shear thinning and normal stress differences. Here, we simulate liquid bridge flows in which cylinders of such liquids are placed between solid plates and extended to the point of rupture. Measurements of the local fluid stress tensor and interface shape provide information on extensional viscosity and rheology, coupled to microscopic information based on the evolution of molecular configurations. The simulations are in good agreement with laboratory data and with the results of macroscopic numerical calculations where available, but provide new and detailed information on the internal dynamics of liquids in extensional flow.
Performance of the hough transform and its relationship to statistical signal detection theory

Abstract A statistical signal detection theory approach can be used for curve detection in digital images corrupted by random noise. This approach is shown to be a refinement of the frequently used Hough transform, resulting in improved performance, both in deciding the presence or absence of a curve in the image and in determining the location in the image of an existing curve. Detection performance is evaluated using receiver operating characteristics (ROC) curves. Location estimation performance is measured by deriving equations for both the Hough transform and the signal detection theory approach for the probability of correctly estimating the location of a curve in noise. The performances of these two approaches are compared for various signal-to-noise ratios and found to be significantly different for some values of signal-to-noise ratio.
Radiative heat transfer in a plane-layer mixture of non-gray particulates and molecular gases

Abstract The interaction between particulate clouds and molecular gases with respect to radiative heat transfer in a one-dimensional, plane-parallel geometry is investigated. The particulates are assumed to have a non-gray absorption coefficient with a power-law dependence on wavenumber. The absorption coefficient of the molecular gases is described by the popular exponential wide-band model. Heat transfer rates are determined through the evaluation of internal and external slab emissivities of the particulate cloud and through evaluation of slab band absorptances for the molecular gases, modified to account for the interaction with the particles. Simple, closed-form expressions for the slab emissivities and slab absorptances are also introduced, resulting in good accuracy.
The Political and Ritual Significance of Bronze Production and Use in Ancient Yunnan

The exceptional quality and enormous quantity of bronzes included in the elite tombs of the Dian Culture in central Yunnan Province provide an excellent opportunity to explore the interplay among craft specialization, ritual, and political power. Although Yunnan contains some of China’s richest deposits of copper, lead, and tin, the early phases of bronze metallurgy there are still very poorly represented in the archaeological record. By the mid-first millennium bc, however, the technology of bronze production had reached a very high level of sophistication, and bronzes played a crucial military, ritual, and social role in Dian society. It appears that a close, symbiotic relationship existed between Dian metallurgical craftsmen and their elite patrons. Present evidence suggests that possession of bronzes, and the control over the means to produce them, invested the Dian elite with the ability to acquire and maintain power and control over their own people and many of their neighbors. Among the Dian, primarily endogenous political and ritual developments fostered the rapid specialization of the metallurgical craft. Under the patronage of the Dian elite, metalworkers developed complicated methods of casting using piece-molds and investment processes (such as lost wax casting), combined with a variety of mechanical joinery techniques to produce vibrant and detailed scenes of warfare, ritual, and other aspects of Dian life. With the careful attention devoted to details of ethnic identification, military prowess, social status, and ritual activities, these objects both legitimated and maintained Dian political and religious power and prestige in the eyes of the Dian people and of their non-Dian neighbors.
Alkyl thiolacrylates: Their preparation and polymerization

A convenient synthesis of alkyl thiolacrylates has been described and a number of the intermediates, as well as the esters, have been characterized. These esters have been found to homopolymerize readily under free radical conditions to give clear plastics which have higher softening points than the corresponding acrylate ester polymers. In general the thiolacrylates copolymerize readily with common vinyl monomers. The reactivity ratios for copolymerization with butadiene have been found to be r1 (butadiene) = 0.35 ± 0.01 and r2 (methyl thiolacrylate) = 0.20 ± 0.05. The butadienemethyl thiolacrylate copolymer prepared from a 90/10 charge ratio to a 45% conversion contained 18.1% of combined methyl thiolacrylate. Tests on the compounded and cured polymer indicate that it has properties very close to those of standard GR-S, except for its higher temperature rise.
Pyruvate Kinase M2 Regulates Gene Transcription by Acting as a Protein Kinase

Pyruvate kinase isoform M2 (PKM2) is a glycolysis enzyme catalyzing conversion of phosphoenolpyruvate (PEP) to pyruvate by transferring a phosphate from PEP to ADP. We report here that PKM2 localizes to the cell nucleus. The levels of nuclear PKM2 correlate with cell proliferation. PKM2 activates transcription of MEK5 by phosphorylating stat3 at Y705. In vitro phosphorylation assays show that PKM2 is a protein kinase using PEP as a phosphate donor. ADP competes with the protein substrate binding, indicating that the substrate may bind to the ADP site of PKM2. Our experiments suggest that PKM2 dimer is an active protein kinase, while the tetramer is an active pyruvate kinase. Expression of a PKM2 mutant that exists as a dimer promotes cell proliferation, indicating that protein kinase activity of PKM2 plays a role in promoting cell proliferation. Our study reveals an important link between metabolism alteration and gene expression during tumor transformation and progression.
The effect on growth of feeding supplemental milk or baby food to the suckling rat

Abstract Suckling rats were fed synthetic rat milk or baby food as dietary supplements amounting to 10% of their total expected daily caloric intake from day 10 to day 16 of life. On day 17, their body lipid levels were significantly higher than those of control pups, and they remained high throughout a 6-week postweaning period of ad libitum food intake. Protein content (at 17 and 60 days of age) was similar in experimental and control groups. Seventeen-day-old pups that had been fed supplemental baby food showed a small but significant increase in DNA levels but no accompanying increase in lean body mass. Rats that received supplemental milk weighed more than either those that received baby food or controls at 17 days of age; however, both experimental groups weighed considerably more at weaning (21 days) than controls. At 60 days of age, their weights were again similar to those of control rats.
Interaction of arena size with different measures of amphetamine effects

Abstract The effects of d-amphetamine (0.0, 0.5, 1.0, 2.0 mg/kg) on feeding and activity of male Holtzman rats were investigated in 3 different size test arenas. Differences in the size of arenas significantly altered the drug's effect on ambulatory activity, but not on feeding or rearing. Also, differences in the size of arenas significantly altered the interrelationship (correlation) of amphetamine's effects on feeding and ambulatory activity, but not the interrelationship of the drug's effects on feeding and rearing. These findings suggest that test arena size differentially influences different general measures of amphetamine effects as well as differentially affecting the interrelationship of amphetamine effects. The importance of the interrelationship (correlation) data to the potential incompatability of the drug's effects is briefly considered.
Crafting an environment for collaborative reasoning

We motivate the need for new environments for collaborative reasoning and describe the foundations of our approach, namely collaboration, semantics, and adaptability. We describe the CRAFT collaborative reasoning interface and infrastructure that we are developing to explore this approach.
Domain Analyses Reveal That Chlamydia trachomatis CT694 Protein Belongs to the Membrane-localized Family of Type III Effector Proteins

The Chlamydia trachomatis type three-secreted effector protein CT694 is expressed during late-cycle development yet is secreted by infectious particles during the invasion process. We have previously described the presence of at least two functional domains within CT694. CT694 was found to interact with the human protein Ahnak through a C-terminal domain and affect formation of host-cell actin stress fibers. Immunolocalization analyses of ectopically expressed pEGFP-CT694 also revealed plasma membrane localization for CT694 that was independent of Ahnak binding. Here we provide evidence that CT694 contains multiple functional domains. Plasma membrane localization and CT694-induced alterations in host cell morphology are dependent on an N-terminal domain. We demonstrate that membrane association of CT694 is dependent on a domain resembling a membrane localization domain (MLD) found in anti-host proteins from Yersinia, Pseudomonas, and Salmonella spp. This domain is necessary and sufficient for localization and morphology changes but is not required for Ahnak binding. Further, the CT694 MLD is able to complement ExoS ΔMLD when ectopically expressed. Taken together, our data indicate that CT694 is a multidomain protein with the potential to modulate multiple host cell processes.
Whole Heart Coronary Imaging with Flexible Acquisition Window and Trigger Delay

Coronary magnetic resonance imaging (MRI) requires a correctly timed trigger delay derived from a scout cine scan to synchronize k-space acquisition with the quiescent period of the cardiac cycle. However, heart rate changes between breath-held cine and free-breathing coronary imaging may result in inaccurate timing errors. Additionally, the determined trigger delay may not reflect the period of minimal motion for both left and right coronary arteries or different segments. In this work, we present a whole-heart coronary imaging approach that allows flexible selection of the trigger delay timings by performing k-space sampling over an enlarged acquisition window. Our approach addresses coronary motion in an interactive manner by allowing the operator to determine the temporal window with minimal cardiac motion for each artery region. An electrocardiogram-gated, k-space segmented 3D radial stack-of-stars sequence that employs a custom rotation angle is developed. An interactive reconstruction and visualization platform is then employed to determine the subset of the enlarged acquisition window for minimal coronary motion. Coronary MRI was acquired on eight healthy subjects (5 male, mean age = 37 ± 18 years), where an enlarged acquisition window of 166–220 ms was set 50 ms prior to the scout-derived trigger delay. Coronary visualization and sharpness scores were compared between the standard 120 ms window set at the trigger delay, and those reconstructed using a manually adjusted window. The proposed method using manual adjustment was able to recover delineation of five mid and distal right coronary artery regions that were otherwise not visible from the standard window, and the sharpness scores improved in all coronary regions using the proposed method. This paper demonstrates the feasibility of a whole-heart coronary imaging approach that allows interactive selection of any subset of the enlarged acquisition window for a tailored reconstruction for each branch region.
Web-based interactive 3D electromagnetic visualization for antenna designs

Electromagnetic radiation patterns are commonly visualized in 3D graphics to facilitate the design of antennas. Existing software are often proprietary and lack of interactive navigation capability for web users. A direct web-based visualization system with real-time interactive rendering capability can benefit EM education and facilitate research and development cycles significantly. This study demonstrates a pilot HTML5 deployment using WebGL-based browser with 3D graphics rendering power for electromagnetic data visualization. Detailed deployment method and exemplar rendering results are presented. The pilot deployment assures the future direction of cloud-based EM computation and web-based visualization.
Dynamic diffuse scattering of X-rays in fcc 4He

A first measurement of the dynamic diffuse scattering (DDS) of X-rays was made in a fcc 4He crystal. The generally preferred method of studying lattice dynamics is through inelastic neutron scattering (INS). INS experiments, however, require large crystals which, in case of the high pressure fcc phase of helium are difficult to achieve and suffer from some poorly resolved phonon signals. An alternate promising technique uses a beryllium sample cell at cryogenic temperatures and excellent quality single crystals. Diffuse X-ray scattering measurements on such fcc samples yield information about the elastic constants in solid 4He. Present test results on a crystal at 241(3) MPa and 23.8(1) K are compared with the results from neutron experiments and several theoretical calculations, including a present Hartree-Fock LCAO model. Various disagreements are found and discussed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Zum ersten mal wurde dynamisch diffuse Streuung von Rontgenstrahlen in einem fcc-4He-Einkristall gemessen. Gitterschwingungen (Phononen) in Einkristallen werden bevorzugt mittels inelastischer Neutronenstreuung (INS) studiert. Jedoch erfordern Messungen mit INS grose Einkristalle, die im Falle der Hochdruckphasen des Heliums nur auserst schwer zu realisieren sind. Daruberhinaus leiden die Phononenspektren unter solch schwierigen experimentellen Bedingungen an mangelnder Energieauflosung. Eine vielversprechende Alternative verwendet kleine Beryllium-Druckzellen in denen bei tiefen Temperaturen Helium-Einkristalle von sehr guter Qualitat wachsen. Die diffuse Rontgenstreuung an solchen Proben liefert Information uber die elastischen Konstanten im festen Helium. Ergebnisse erster Messungen bei 241(3) MPa und 23.8(1) K werden in dieser Arbeit vorgestellt und mit Ergebnissen anderer Arbeiten verglichen, wie fruhe Neutronenstreuexperimente und theoretische Arbeiten (inklusive Rechnungen innerhalb eines Hartree-Fock LCAO Modells). Die deutlich streuenden Ergebnisse werden diskutiert.
Surface assembly: Graphene goes undercover.

The formation of robust monolayers of organic molecules on graphene substrates not only sweeps this material's defects under a self-assembled carpet, but may help it achieve its full potential as a building block for molecular electronic devices.
Perspectives On Self-Directed Learning:

Self-directed learning in adults is considered predominantly a process of self-instruction. This conception is inadequate because it fails to account for persistence in learning and excludes adults who are unable to plan self-instruction. These inadequacies, however, can be addressed by studying self-directed learning as it relates to the learner's personality. Linking self-directed learning and personality has several advantages: Self-directed learning could be studied independent of the mode of learning an individual selects, a relatively stable indicator of self-directed learning-personality-would be available for study, and the personality characteristics leading an individual to initiate and persist in learning would provide a more unified and comprehensive focus for the study of self-directed learning.
CENTRAL NERVOUS SYSTEM INVOLVEMENT IN RICKETTSIAL DISEASES

The Rickettsia are obligate intracellular parasites that are usually spread to humans by insects and typically produce vasculitides. The prototypic rickettsial disorder in the United States is Rocky Mountain spotted fever (RMSF). The differential diagnosis of RMSF and related disorders includes other conditions that produce vasculitis, most importantly meningococcemia. The rickettsial disorders are usually treated effectively with tetracycline derivatives.
Perpendicular Vibrations of the Ammonia Molecule

The vibration frequency ${\ensuremath{\nu}}_{2}$ of N${\mathrm{H}}_{3}$ is identified by means of the combination bands ${\ensuremath{\nu}}_{2}\ifmmode\pm\else\textpm\fi{}{\ensuremath{\nu}}_{3}$ at 2.2\ensuremath{\mu} and 4.0\ensuremath{\mu}, in each of which the spacing between component bands is about 16 ${\mathrm{cm}}^{\ensuremath{-}1}$. From the difference band the numerical value of ${\ensuremath{\nu}}_{2}$ is fixed at 3415 ${\mathrm{cm}}^{\ensuremath{-}1}$. The fundamental band may be recognized in the weak and complex background of the absorption at 3\ensuremath{\mu}. The coefficient ${\ensuremath{\zeta}}_{2}$ of the vibrational angular momentum is approximately +0.6.The second perpendicular fundamental band at 6\ensuremath{\mu} is partially resolved, and is in good agreement with the expected pattern if ${\ensuremath{\zeta}}_{4}$ equals -0.3. The indicated value of ${\ensuremath{\nu}}_{4}$ is 1628 ${\mathrm{cm}}^{\ensuremath{-}1}$. The numerical values of ${\ensuremath{\zeta}}_{2}$ and ${\ensuremath{\zeta}}_{4}$ do not agree well with those predicted theoretically.The parallel component of $2{\ensuremath{\nu}}_{4}$ is found at 3220 ${\mathrm{cm}}^{\ensuremath{-}1}$, and two pairs of parallel combination bands, ${\ensuremath{\nu}}_{1}+{\ensuremath{\nu}}_{3}$ at 4270 and 4303 ${\mathrm{cm}}^{\ensuremath{-}1}$ and $2{\ensuremath{\nu}}_{4}+{\ensuremath{\nu}}_{3}$ at 4177 and 4217 ${\mathrm{cm}}^{\ensuremath{-}1}$.
Group-Ordered SPRT for Decentralized Detection

The problem of decentralized detection in a large wireless sensor network is considered. An adaptive decentralized detection scheme, group-ordered sequential probability ratio test (GO-SPRT), is proposed. This scheme groups sensors according to the informativeness of their data. Fusion center collects sensor data sequentially, starting from the most informative data and terminates the process when the target performance is reached. Wald's approximations are shown to be applicable even though the problem setting deviates from that of the traditional sequential probability ratio test (SPRT). To analyze the efficiency of GO-SPRT, the asymptotic equivalence between the average sample number of GO-SPRT, which is a function of a multinomial random variable, and a function of a normal random variable, is established. Closed-form approximations for the average sample number are then obtained. Compared with fixed sample size test and traditional SPRT, the proposed scheme achieves significant savings in the cost of data fusion.
Identification of additional genes that influence baculovirus late gene expression.

Abstract We were unable to confirm transient late gene expression using constructs of 18 genes that had been reported to support Autographa californica multinucleocapsid nucleopolyhedrovirus (AcMNPV) late gene expression when transfected into Spodoptera frugiperda cells [Lu, A., and Miller, L. K. (1995). J. Virol. 69, 975–982]. Three genes ( orf66, orf68, and orf41 ) were included, all or in part, in the constructs used in that study, but they had not been independently tested. Therefore we investigated these and neighboring orf s for their influence on late gene expression. We found that orf41 was required for late gene expression and that sequences within orf45 appeared to be required for the expression of orf41 . Although orf66 and orf68 did not appear to affect late gene expression, orf69 stimulated expression. orf69 was found to have high homology to recent entries in GenBank from a variety of organisms. In addition, it was found that orf121 , which was shown to be involved in early gene expression, and the viral homolog of pcna did not influence late gene expression.
Detection of simulated microcalcifications in digital mammography-effects of quantum and anatomic noises: preliminary study

To study the effects of overlapping anatomy on microcalcification detection at various incident exposure levels. Images of an anthropomorphic breast phantom (RMI 169) overlapping with simulated microcalcifications ranging from 150 to 212 μm in size placed in two breast density regions, fatty and heterogeneously dense, were acquired with an a-Si/a-Se flat panel based digital mammography system (Selenia) operated with Mo-Mo target/filter combination at 28 kVp. The mammograms were exposed with 20, 30, 40, 60, 80, 120, 160, 240 and 325 mAs for varying the exposure level. A 4-AFC study was performed for evaluation of the detection performance. Four 400×400-pixel images were displayed as 2×2 array on a LCD flat panel based review workstation. One of the four images contained a cluster of five microcalcifications and was randomly placed in one of the four quadrants. A physicist was asked to select the image containing the microcalcifications and to report the number of visible microcalcifications. The fraction of correct responses was computed with two different criteria: (1) the selected images contained one or more microcalcifications, and (2) the selected images contained 4 or 5 visible microcalcifications. The statistical significance of the differences in fractions for different exposure levels and regions was evaluated. The results showed that, if visibility of one or more microcalcifications is required, the fractions of correct responses were 1 for all size groups and most exposure levels in both fatty and heterogeneously dense regions. If a visibility of 80% or more of the microcalcifications was required, the fractions of correct responses significantly decreased in both regions. The results indicated that microcalcification detection in the fatty region appeared to be mainly limited by the quantum noise, and that in the heterogeneously dense region may be limited by both the anatomic noise and the quantum noise.
NT-15STEREOTACTIC LASER THERMAL ABLATION OF RECURRENT POSTERIOR FOSSA METASTATIC LESION: DESCRIPTION OF NEW TECHNOLOGY FOR INFRATENTORIAL TUMORS REFRACTORY TO CONVENTIONAL THERAPIES

BACKGROUND: Stereotactic radiofrequency thermal ablation is a minimally invasive innovative technique that achieves real time tumor destruction. The procedure is safe and effective with real time MRI feedback. We describe the use of stereotactic radio-frequency thermal ablation of posterior fossa metastatic lesion that was refractory to surgical resection and radiosurgery. METHODS: A 67-year-old lady with pulmonary adenocarcinoma developed recurrent metastatic left cerebellar lesion, which was refractory to surgery and radiosurgery. The patient was symptomatic from this lesion and required at least debulking to improve quality of life. She underwent stereotactic radio-frequency thermal ablation using frame-less steretotaxy. Pre-operative imaging using fiducials screwed to the skull was registered in a navigation system that aided in precise placement of skin incision. A specially engineered precision access device was used to drill a 3.2-mm hole in the optimum trajectory and to place a 1.65-mm diameter laser applicator and probe. RESULTS: After confirmation of probe placement with MRI, ablation was accomplished over 2.65 x 1.22 cm of lesion under multi-planar real -time thermal imaging. The tumor approximated facial nerve exit at the brainstem. Real-time feedback with safety markers placed along the seventh cranial nerve exit zone at brainstem and middle cerebellar peduncle regulated dose and duration of therapy. The patient suffered no new neurological deficit and was discharged home the following day without any complication. At 6-month follow-up, the patient continued to show good tumor control, without new symptoms, remaining neurologically and radiologically unchanged. CONCLUSIONS: This case illustrates the utility of radio-frequency thermal ablation for metastatic lesions in the infratentorial space especially when conventional therapies have been either exhausted or found unsuitable. With safety markers protecting brainstem and cranial nerves, good tumor control can be achieved without suffering significant neurological deficit. Also, minimal invasiveness and negligible risk advocate for possibility of multiple sessions, performed safely.
Time-resolved spectroscopy of energy and electron transfer processes in the photosynthetic bacterium Heliobacillus mobilis

The kinetics of excitation energy transfer and electron transfer processes within the membrane of Heliobacillus mobilis were investigated using femtosecond transient absorption difference spectroscopy at room temperature. The kinetics in the 725- to 865-nm region, upon excitation at 590 and 670 nm, were fit using global analysis. The fits returned three kinetic components with lifetimes of 1–2 ps and 27–30 ps, and a component that does not decay within several nanoseconds. The 1- to 2-ps component is attributed to excitation equilibration to form a thermally relaxed excited state. The 27- to 30-ps phase corresponds to the decay of the relaxed excited state to form a charge-separated state. The intrinsic energy and electron transfer rates were estimated using the experimental results and theoretical models for excitation migration and trapping dynamics. Taking into account the number of antenna pigments and their spectral distribution, an upper limit of 1.2 ps for the intrinsic time constant for charge separation in the reaction center is calculated. This upper limit corresponds with the trapping-limited case for excitation migration and trapping. Reduction of the primary electron acceptor A0 was observed in the 640 to 700 nm region using excitation at 780 nm. An instantaneous absorbance increase followed by a decay of about 30 ps was observed over a broad wavelength region due to the excited state absorption and decay of BChl g molecules in the antenna. In addition, a narrow bleaching band centered at 670 nm grows in with an apparent time constant of about 1.0 ps, superimposed on the 30-ps absorbance increase due to excited state absorption.(ABSTRACT TRUNCATED AT 250 WORDS)
Redefining Human Vitamin D Sufficiency: Back to the Basics

The role of the endocrine vitamin D pathway in regulating the serum calcium concentration in man is well described. In the presence of a low serum calcium level, the vitamin D metabolic pathway is called upon to produce more of the active vitamin D hormone, 1, 25-dihydroxyvitamin D (1, 25-D), via up-regulation of the CYP27b1-hydroxylase activity in the kidney. The consequence is mobilization of skeletal calcium stores to return the circulating calcium level back to the normal range. On the other hand, when the serum calcium level increases, endocrine forces move to suppress renal 1, 25D production and squelch bone resorption. It is now known that vitamin D metabolites also operate in an autocrine, paracrine and intracrine mode to control vitamin D receptor-directed biological responses at the tissue level. Because the metabolism and action of vitamin D occurs at the tissue level in this situation, use of circulating vitamin D metabolites and biomarkers to ascertain the local action of the vitamin D pathway is often misleading. This mini-review seeks to compare and contrast the operation of the vitamin D pathway at the endocrine and tissue level.
Photopatterning and Degradation Study of Dextran-Glycidyl Methacrylate Hydrogels

An approach to synthesizing photopatternable enzymatic degradable dextran hydrogel is presented. The glycidyl methacrylate derivatized dextran (Dex-GMA) was first prepared by reacting dextran with glycidyl methacrylate at 45°C with grafting efficiency of 10%. The degree of substitution (DS) was confirmed by 1H-NMR. Next, Dex-GMA hydrogels were prepared by crosslinking in the presence of a crosslinker: N,N′- methylene-bisacrylamide (NMBA), and a photoinitiator: 2,2′-dimethoxy-2-phenyl acetophenone (DMPA) in dimethyl sulfoxide (DMSO) solution. Further, the Dex-GMA hydrogels were photopatterned using liquid-phase photopolymerization (LP3) technique. The structure size ranged from 5 mm to 300 μm and three different shapes of structures- - —round, square, and star- - —were demonstrated. The patterned Dex-GMA hydrogel structures not only exhibited mechanical robustness but also biodegradability. The dextranase-catalyzed degradation of Dex-GMA hydrogels with different DS was investigated at 37°C. The morphology of the degraded Dex-GMA hydrogels determined by SEM revealed the degree of enzymatic degradation due to dextranase. The Dex-GMA hydrogel was fully degraded by dextranase with concentration of 2 U/ml in 5 days. The Dex-GMA hydrogel also showed the ability to be readily integrated with microfluidics. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Autonomic Effects on the QT Interval

Background: This study was designed to evaluate the effects of autonomic tone on the QT interval, using conventional and heart rate independent analysis. Effects of autonomic tone on the QT interval have been studied either using rate correction formulae or during fixed rate atrial pacing, both of which have been associated with problems. Since most autonomic interventions are associated with heart rate changes, separation of “true” autonomic effects from rate related effects on the QT interval is essential. Methods: Electrocardiographic recordings were performed in 14 healthy volunteers during: (1) sympathetic stimulation (tilt, epinephrine infusion, isoproterenol infusion, and exercise); (2) β-adrenergic blockade; (3) parasympathetic blockade; (4) autonomic blockade; (5) tilt following autonomic blockade; (6) parasympathetic stimulation (phenylephrine infusion); and (7) isolated α-adrenergic stimulation (phenylephrine infusion following atropine). The QT interval was adjusted for heart rate using Bazett's formula. Heart rate independent analysis was performed between conditions with similar cycle lengths. Results: QT interval measurements were reproducible and exhibited the typical QT-RR relationship. Sympathetic stimulation decreased the RR interval and prolonged the QTc interval. Parasympathetic blockade also increased the QTc. Heart rate independent analysis of the effects of β-blockade showed a shortening of the QT (from 368.5 ± 20.5 ms to 355.9 ± 17.9 ms; n = 8). Alpha-adrenergic stimulation also decreased the QT interval from 302.4 ± 16.8 ms to 294.3 ± 17.7 ms (n = 7). Conclusion: Sympathetic stimulation prolongs the QT interval, while β-blockade shortens it. Alpha-adrenergic stimulation also shortens the QT interval. Autonomic effects on the QT interval as assessed by heart rate independent analysis may help separate the true autonomic effects from rate related effects.
On the magnetostratigraphic age of Nauru Basin basalts of the western Pacific Ocean and timing of Ontong Java volcanism

Abstract Cretaceous lava flows overlie Jurassic to Early Cretaceous oceanic crust in the Nauru Basin of the western equatorial Pacific, but their exact age and origin is controversial. In one model, they are generically related to volcanism forming the Ontong Java Plateau. However, paleomagnetic data from basalts recovered by ocean drilling in the Nauru Basin have been interpreted as recording numerous geomagnetic reversals, suggesting the Nauru Basin basalts are older than the Early Aptian flows on the Ontong Java Plateau, and the correlative volcanism seen in the western equatorial and southwestern Pacific Ocean basin. Here, we examine the magnetic fidelity of the Nauru Basin basalts through rock magnetic and paleomagnetic approaches. We find the magnetic carriers in the lavas are unlike most basaltic units recovered by oceanic drilling in that they are magnetically soft. This quality makes the rocks especially prone to the acquisition of secondary magnetic components induced during drilling. We demonstrate that the reversed polarity intervals are illusory, and instead record subtle changes in magnetic hardness that result in partial and complete overprinting by the magnetic field associated with the drill string (e.g., the core barrel, drill pipe and bit). The recognition of these magnetic overprints, the identification of only normal polarity in the Nauru Basin basalts, and a critical consideration of the available radiometric and biostratigraphic age data lead us to conclude that coeval formation of the Nauru Basin basalts and Ontong Java Plateau in Aptian times remains a viable hypothesis.
The audiometric evaluation of adult aphasics.

Sixty-seven adult aphasics were tested audiometrically using ascending and descending approaches to threshold. The three lowest hearing levels at which responses were obtained for each of the appro...
Experiments on learning in zebrafish (Danio rerio): A promising model of neurocognitive function

The past decade has seen rapid proliferation of behavioral research with zebrafish, and an emergence of interest in their potential as a model of neurocognitive function. Already, zebrafish have been proposed as a model of autism, Alzheimer's, drug abuse, schizophrenia, and other disorders involving cognitive dysfunction. Zebrafish have the sophisticated sensory and motor systems necessary for complex learning experiments, and their power as a genetic and developmental model has already been established. Currently, however, learning procedures remain unrefined, and behavioral variability presents a major problem for researchers. Before zebrafish can be effectively used to study the neurological bases of learning, a set of robust and replicable techniques must be characterized and standardized. The purpose of this review is to provide an overview and critique of learning procedures that have been used with zebrafish and their results. We hope that such an analysis will prove useful in this early stage of research to guide future learning experiments and thereby improve the efficiency and validity of research with this promising new animal model.
IN-NETWORK DATA AGGREGATION VIA ANT-COLONY OPTIMIZATION IN WIRELESS SENSOR NETWORKS

Energy efficiency is an important issue of wireless sensor networks. In-network data aggregation is a data collection technique that improves energy efficiency and alleviates congestive routing traffic by reducing data forwarding in wireless sensor networks. Ant-colony aggregation is a distributed algorithm that provides an intrinsic way of exploring the search space to optimize settings for optimal data aggregation. This paper aims to refine the heuristic function and the aggregation node selection method to maximize energy efficiency and to extend network lifetime. Two proposed algorithms are shown to yield longer maximum lifetime than the conventional algorithm with the same hop-count delay. One of the proposed algorithms is shown to have improved scalability than the conventional algorithm.
Contrasting Influences of Selenium Status and Mercury Exposures on Environmental Health – an Introduction to the Special Topic: Selenium as a Bioindicator of Susceptibility to Mercury Exposures

The current issue of Environmental Bioindicators is the first of two presenting invited articles describing interactions between mercury (Hg) and selenium (Se). The articles that appear in the curr...
A study of the effects of fasting time on the one hour glucose tolerance test

Abstract The effect of time since last food intake upon the value of glucose one hour post challenge is examined on a large group of asymptomatic patients. A number of multivariate statistical techniques are employed, and after a series of determinations, the conclusion is reached that the time since last eating has a relatively marginal effect on the glucose tolerance test.
Blood loss associated with radical cystectomy: A prospective, randomized study comparing Impact LigaSure vs. stapling device

Objectives Radical cystectomy (RC) is associated with significant blood loss and transfusion requirement. We performed a prospective, randomized trial to compare blood loss, operative time, and cost using 2 different and commonly employed approaches to tissue ligation and division during RC: mechanical (stapler device) and electrosurgical (heat-sealing device).
Microwave-assisted multicomponent domino cyclization–aromatization: an efficient approach for the synthesis of substituted quinolines

A solid acid-catalyzed microwave-assisted synthesis of substituted quinolines is described. The quinolines were synthesized by a multicomponent domino reaction of anilines, aldehydes and terminal aryl alkynes. The synthetic pathway involves the formation of an imine, followed by the intermolecular addition of an alkyne to the imine. This intermediate immediately undergoes ring closure and oxidative aromatization. The reaction is catalyzed by montmorillonite K-10, a strong, environmentally benign solid acid. The multicomponent approach yields the products with nearly 90% atom economy in excellent yields in a matter of minutes. The use of microwave activation reduces the reaction time significantly.
Preparation of TiO2–SiO2 aperiodic mesoporous materials with controllable formation of tetrahedrally coordinated Ti4+ ions and their performance for photocatalytic hydrogen production

Abstract The efficiency of photocatalytic water splitting for TiO2 dispersed on four SiO2 aperiodic porous supports is discussed in this work. The four TiO2–SiO2 composite materials were prepared via a sol–gel method and then subjected to supercritical drying, natural drying, rotatory vapor drying, or hydrothermal synthesis and the materials were subsequently calcined under identical conditions. These synthetic strategies result in differences in textural properties (specific surface area, pore diameter etc.) and in the amount of tetrahedrally coordinated Ti4+ ions. The TiO2–SiO2 materials were thoroughly characterized by powder X-ray diffraction (XRD), UV–Vis diffuse reflectance spectra (DRS), nitrogen adsorption studies, FT-IR spectroscopy, transmission electron microscopic (TEM) studies, and electron paramagnetic resonance (EPR) studies. The photocatalytic activity for hydrogen production is maximum when the amount of tetrahedrally coordinated Ti4+ ions is high. Thus, this work provides guidance towards the preparation of photoactive materials for generating hydrogen from water.
Extracolonic Tumors of the Gastrointestinal Tract Detected Incidentally at Screening CT Colonography

The aim of this article is to report our experience with incidental detection of extracolonic tumors of the gastrointestinal tract identified prospectively at screening CT colonography. A total of 2014 patients (1097 females, 917 males; mean age, 56.9 years) underwent primary CT colonography evaluation at our institution over an 18-month period. Following cathartic preparation and colonic distention, supine and prone multidetector CT scans were obtained with thin-collimation low-dose technique without intravenous contrast. We reviewed our database for lesions of the extracolonic gastrointestinal tract that were detected during the prospective reading. Focal extracolonic gastrointestinal tract lesions were prospectively detected in 10 (0.5 percent) of 2014 patients (8 females; 2 males; mean age, 58.5 years). All patients were asymptomatic. Tumor locations included ileum (n = 3), stomach (n = 3), jejunum (n = 2), and appendix (n = 2). Mean tumor size was 2.2 (range, 0.8–3.4) cm. Lesions in eight patients were subsequently confirmed by conventional or capsule endoscopy and/or by intravenous contrast-enhanced CT. Seven lesions were surgically excised and one was removed at endoscopy; two patients with lipomas did not undergo further evaluation or treatment. Final diagnoses were benign in all cases and included lipoma (n = 3), small-bowel hamartoma (n = 2), appendiceal mucinous cystadenoma (n = 2), gastric leiomyoma (n = 1), small-bowel lymphangioma (n = 1), and gastric fundic gland polyp (n = 1). Incidental extracolonic tumors of the gastrointestinal tract detected at screening CT colonography were all asymptomatic and benign but often prompted more invasive workup. Although the incidence of these tumors was relatively low, widespread population screening with CT colonography would result in new surgical referrals for these findings.
Vertex cuts, random walks, and dimension reduction in series-parallel graphs

We consider questions about vertex cuts in graphs, random walks in metric spaces, and dimension reduction in L1 and L2; these topics are intimately connected because they can each be reduced to the existence ofvarious families of real-valued Lipschitz maps on certain metric spaces. We view these issues through the lens of shortest-path metricson series-parallel graphs, and we discussthe implications for a variety of well-known open problems. Our main results follow.Every n-point series-parallel metric embeds into l1dom with O(√ log n) distortion, matchinga lower bound of Newman and Rabinovich. Our embeddings yield an O(√log n) approximation algorithm for vertex sparsestcut in such graphs, as well as an O(√log k) approximate max-flow/min-vertex-cut theorem for series-parallel instances withk terminals, improving over the O(log n) and O(log k) boundsfor general graphs.Every n-point series-parallel metric embeds withdistortion D into l1d with d = n1/Ω(D2),matching the dimension reduction lower bound of Brinkman andCharikar.There exists a constant C > 0 such that if (X,d) is aseries-parallel metric then for every stationary, reversible Markovchain Ztt=0∞ on X, we have for all t ≥ 0, E[d(Zt,Z0)2] ≤ Ct ·, E[d(Z0,Z1)2]. More generally, we show thatseries-parallel metrics have Markov type 2. This generalizesa result of Naor, Peres, Schramm, and Sheffield for trees.
A model of through-air drying of tufted textile materials

Abstract A transient two-dimensional mathematical model is developed to simulate the through-air drying process for tufted textile materials. The heat and mass transfer in a cylindrical porous medium and the air flowing around it are analyzed separately. First, thermal and mass circuits are used to analyze the simultaneous heat and mass transfer within the porous medium. Then, the equations of the conservation of mass and energy are written for the drying medium. The resulting system of three non-linear differential equations is numerically solved by an implicit finite difference method. The numerical solutions are compared with experimental drying results obtained using magnetic resonance imaging (MRI) and a laboratory through-air dryer (LTAD).
Pollutant Transport in Geomedia Using X-ray Computed Tomography

Abstract Computed tomography (CT) measurement systems have been introduced as a method to measure fluid transport at the macropore-scale to estimate transport parameters. The objective of this study was to use x-ray CT methods to measure transport of iodophenol solution in geomedia columns and estimate spatial distributions of chemical retardation. An initial CT-measured breakthrough curve experiment was conducted with potassium iodide to spatially estimate pore-water velocity and dispersivity in the geomedia core, with a subsequent transport experiment with iodophenol to estimate the spatial distribution of chemical retardation. A geomedia core was removed from the surface horizon of Sarpy loamy sand (Typic Udispamment). Spatial distributions followed a fractal pattern with dimension values similar among pore-water velocity, dispersivity and retardation coefficient parameters. The retardation coefficient estimated using CT methods was similar compared to the dynamic fluid experiment indicating this new method may be appropriate for pollutant transport analysis. This study illustrates that the CT method is useful for evaluating solute transport on a macropore-scale for porous materials.
Ascorbate protects against tert-butyl hydroperoxide inhibition of erythrocyte membrane Ca2+ + Mg2(+)-ATPase.

Abstract The incubation of erythrocyte suspensions or isolated membranes containing a residual amount of hemoglobin (0.04% of original cellular hemoglobin) with tert -butyl hydroperoxide (tBHP, 0.5 m m ) caused significant inhibition of basal and calmodulin-stimulated Ca 2+ + Mg 2+ -ATPase activities and the formation of thiobarbituric acid reactive products measured as malondialdehyde. In contrast, the treatment of white ghosts (membranes not containing hemoglobin) with tBHP (0.5 m m ) did not lead to appreciable enzyme inhibition within the first 20 min and did not result in malondialdehyde (MDA) formation. However, the addition of either 10 μ m hemin or 100 μ m ferrous chloride + 1 m m ADP to white ghosts produced hydroperoxide effects similar to those in pink ghosts (membranes with 0.04% hemoglobin). The concentrations of hemin and ferrous chloride which caused half-maximal inhibition of Ca 2+ + Mg 2+ -ATPase activity at 10 min were 0.5 and 30 μ m , respectively. The effects of several antioxidants (mannitol, thiourea, hydroxyurea, butylated hydroxytoluene, and ascorbate) were investigated for their protective effects against oxidative changes resulting from tBHP treatment. Over a 30-min incubation period only ascorbate significantly reduced the enzyme inhibition, MDA formation, and protein polymerization. Thiourea and hydroxyurea decreased MDA formation and protein polymerization but failed to protect against the enzyme inhibition. Butylated hydroxytoluene was similar to thiourea and hydroxyurea but with better protection at 10 min. Mannitol, under these conditions, was an ineffective antioxidant for all parameters tested.
Dynamic Responses in Polymer-Clay Gels

The shear orientation of three polymer-clay gels has been investigated by means of small angle neutron scattering (SANS). The gels have the same polymer and clay concentrations but different polymer molecular weight. The polymer is adsorbed to the clay platelets. While long polymer chains can interconnect several platelets shorter polymer chains cannot. Although the polymer concentration is above c* the polymer chain length and cross linking between clay platelets strongly influence their shear orientation which leads to anisotropy in SANS. Our data suggest that the flow is strong enough to enhance and maintain a continuous increase in the shear orientation of the polymer clay gels only when the polymer chains are long enough to interconnect or strongly entangle between platelets.