cssi/SciSciGPT-SciSciNet huggingface dataset:
An Experimental Study of Natural Convection in a Toroidal Loop

Velocity and temperature profiles were measured at the entrance and exit to the heating section of a toroidal thermosyphon loop operating under steady flow conditions for a range of heat inputs. Velocity measurements were made with a laser-Doppler velocimeter and temperature measurements with a small thermocouple probe. Detailed results are presented for the longitudinal and circumferential components of the velocity for four heat inputs. The data for cross-stream secondary flows and streamwise flow reversals emphasize the importance of including three-dimensional effects in analyses of these systems.
A genetic link between morphogenesis and cell division during formation of the ventral furrow in Drosophila.

Stages in development with rapid transitions between mitosis and morphogenesis may require specific mechanisms to coordinate cell shape change. Here we describe a novel mitotic inhibitor that acts during Drosophila gastrulation to counteract String/Cdc25, specifically in the cells that invaginate to form the mesoderm. We have identified two genes, fruhstart and tribbles, that are required for this ventral inhibition. tribbles encodes a kinase-related protein whose RNA, however, is also present outside of the ventral region. Effective inhibition of mitosis in the cells of the ventral furrow depends on the transcription factor Snail that triggers the ventral cell shape changes. When overexpressed in a microinjection assay, Tribbles directly inhibits mitosis. We propose that Fruhstart and Tribbles form a link between the morphogenetic movements and mitotic control.
Hydrogenation of Phenylethanol and Acetylcyclohexane over Pt

The control of intramolecular selectivity when both unsaturated C[double bond]C bonds and carbonyl groups are present is of commercial importance. Group VIII metals, particularly Ni and Pt, are used to hydrogenate aromatic hydrocarbons, and copper chromite catalysts have routinely been used to hydrogenate carbonyl groups in aromatic molecules as they are relatively inactive for hydrogenating aromatic rings. The authors have recently studied acetophenone (C[sub 6]H[sub 5]COCH[sub 3]) hydrogenation over Pt to determine the relativistic rates of phenylethanol (C[sub 6]H[sub 5]CHOHCH[sub 3]) formation versus acetylcyclohexane (C[sub 6]H[sub 11]COCH[sub 3]) formation and to examine the influence of the support on product selectivity. Phenylethanol constituted about 60-70 mole% of the product over typical Pt catalysts such as Pt/SiO[sub 2] and Pt/[eta]-Al[sub 2]O[sub 3], even at conversions up to 50%; however, the use of TiO[sub 2] as a support shifted the selectivity to 90% or higher. There are numerous products possible in this reaction network, and two major considerations exist to account for the high selectivity to PhEt, especially at high acetophenone conversions-the intrinsic hydrogenation rates of the various compounds or their relative surface coverages under reaction conditions, i.e., competitive adsorption. To see which of these two factors is predominant in this reaction system,more » the vapor-phase hydrogenation of phenylethanol (PhEt) and acetylcyclohexane (AcCy) was studied over Pt and compared to acetophenone (AcPh) hydrogenation rates. Neither PhEt nor AcCy hydrogenation over Pt has been studied; consequently, the first specific activities of these reactions are reported here. 6 refs., 3 figs., 3 tabs.« less
Identification, diagnosis and treatment of heparin-induced thrombocytopenia and thrombosis: A registry of prolonged heparin use and thrombocytopenia among hospitalized patients with and without cardiovascular disease : The complication after thrombocytopenia caused by heparin (CATCH) registry steering committee

Background: Heparin-induced thrombocytopenia (HIT) is estimated to occur in 1–5% of all patients receiving heparin, and 25–50% of such cases develop heparin-induced thrombocytopenia with thrombosis (HITT) A conservative estimate based only on cardiovascular patients suggests that in the United States approximately 100,000 patients develop thrombocytopenia, and 25–50,000 develop HITT annually. Both HIT and HITT are associated with high morbidity and mortality and represent substantial worldwide public health concerns.
Global electronic structure of semiconductor alloys through direct large-scale computations for III-V alloys Ga x In 1 − x P

We critically examine two nominally equivalent approaches for treating a random alloy: (1) by using one very large supercell as a direct simulation of the alloy and (2) by performing configuration averaging over many smaller supercells; and the common practice using a virtual crystal as the reference for analyzing the alloy band structure and discussing the electronic transport in the alloy. Specifically, (1) we show that, in practice, the size of the ``very large'' supercell depends on the particular property of interest, and the ideal of configuration averaging is only useful for certain properties. (2) We also examine the assumed equivalency by comparing the results of the two approaches in band-gap energy, energy fluctuation, and intervalley and intravalley scattering, and conclude that the two approaches often lead to nonequivalent physics. (3) We use a generalized moment method that is capable of computing the global electronic structure of a sufficiently large supercell (e.g., \ensuremath{\sim}260 000 atoms) to obtain the intrinsic broadening of a \ensuremath{\Gamma}-like electron state caused by the ``inelastic'' intravalley scattering in a direct-band-gap semiconductor alloy. (4) We demonstrate an efficient way to construct the effective dispersion curves of the alloy with high accuracy for calculating effective masses and examining anisotropy and nonparabolicity of the dispersion curve. (5) Finally, we discuss the limitation of using the virtual-crystal approximation as the reference for evaluating alloy scattering and studying transport properties.
Origin of profound changes in powder properties during wetting and nucleation stages of high-shear wet granulation of microcrystalline cellulose

Abstract The aim of this work was to understand the evolution of powder tabletability and flowability during wetting and nucleation stages of high-shear wet granulation (HSWG). Microcrystalline cellulose (MCC) was granulated with water using a high-shear process. Granule morphology, surface texture, size, porosity, specific surface area, tabletability, and flowability were characterized. MCC granulated with 5% water showed no change in tabletability but significantly improved flowability, corresponding to smoother surfaces and lower surface area. From 5% to 25% water, tabletability decreased by 1/4 but flowability remained unchanged. Granule shape and porosity remained unchanged while surfaces were smoothened, leading to decreased surface area. From 25% to 35% water, MCC granules became more round. There was another sharp decrease in tabletability but powder flowability remained unchanged. Forty-five percent of water led to more particle rounding and commencement of nucleation, which only slightly impacted tabletability and flowability. From 0% to 45% water, granule size decreased slightly and could not explain the significant changes in powder tabletability and flowability. Deteriorated tabletability was instead caused by surface smoothing, granule densification, and granule rounding. Enhanced powder flowability was caused mostly by surface smoothing with granule rounding as a minor contributor.
Unusual antibody-induced modulation of surface antigens in the cell coat of a bloodstream trypanosome

Unlike other eukaryotic cells, Trypanosoma lewisi forms caps at 0 degrees C when incubated with rabbit immunoglobulin G(IgG) directed against surface IgG from the rat host. The host IgG, which is specific for parasite antigens, probably does not cause capping of these antigens in vivo, since trypanosomes treated with Fab fragments directed against rat IgG are uniformly labeled and do not cap at 0 degrees C or 37 degrees C.
A case study of a law enforcement council: Economy of scale and scope or too costly for agencies?

This research fills some gaps in the literature regarding the viability and sustainability of law enforcement councils for policing in the twenty-first century. The Metropolitan Law Enforcement Council (Metro-LEC) is a non-profit organization comprising 43 law enforcement agencies in the Commonwealth of Massachusetts that have pooled resources and regionalized selected police services. The amalgamation provides services to small- and medium-sized police agencies to address incidents that go beyond their capability in scale/duration and in scope/skills. Results are presented from multi-wave surveys of frontline officers as well as surveys administered to the chief executive officers in member police agencies regarding their perceptions of the organization. In addition, a cost analysis presents a comparison between the costs of operating regionalized police units to the costs of operating those units in-house. The overall findings conclude that a law enforcement council approach provides needed services to area police agencies that are valued, utilized, cost effective and sustainable over time.
Aggregation of hemoglobin S modified by bifunctional imidoesters

Sickle hemoglobin (Hb S) was cross-linked by two types of bifunctional imidoesters, dimethyladipimidate (DMA) and dimethyl-3,3'-dithiobispropionimidate (DTBP). These modified hemoglobins were separated into monomer, dimer and polymer fractions by gel filtration. All of these modified hemoglobins showed extremely left-shifted oxygen equilibrium curves with no cooperativity. The stabilities of these hemoglobins were also decreased. The solubilities of these modified hemoglobins in high-phosphate buffers were lower than those of native Hb S. Studies on the kinetics of the aggregation of these modified hemoglobins showed that intracross-linked Hb S with DMA and DTBP (DMA- and DTBP-modified monomeric Hb S) still retained the capability of aggregation with a delay time, while intercross-linked Hb S with DMA and DTBP (DMA- and DTBP-modified oligomeric Hb S) aggregated without a delay time. When the kinetics of aggregation was measured for mixtures of modified and native deoxy-Hb S, DMA-modified monomeric deoxy-Hb S shortened the delay time prior to aggregation of native deoxy-Hb S. The other modified deoxy-Hb S did not affect the delay time, suggesting that these modified oligomeric hemoglobins neither participate in the formation of nuclei nor copolymerize with native deoxy-Hb S.
Characterization of virulence, colony morphotype and the glycopeptidolipid of Mycobacterium avium strain 104.

Abstract Setting : Members of the Mycobacterium avium complex (MAC) are responsible for mycobacterial disease in children, the aged and in immunocompromised individuals. The complex consists of different species, serovars and morphologic forms that vary in virulence. One isolate of the MAC is currently being sequenced (MAC 104) and was chosen based on its derivation from an AIDS patient and the fact that it could be genetically manipulated. Objective : MAC 104 was therefore analyzed for virulence, colony morphotype and expression of the glycopeptidolipid (GPL) responsible for serotying differences and the rough to smooth morphological switch. Results : The isolate was found to be virulent in the murine model of low-dose aerosol infection in that it could colonize the lung, proliferate within the tissue and disseminate to other organs. MAC 104 expressed a variety of colony morphotypes, the most prevalent of which were smooth opaque, smooth transparent and rough. All three morphotypes could persist in the lung; however, the transparent and rough morphotypes grew more rapidly in vivo . The rough morphotype was unusual in that it expressed an atypical form of the GPL usually absent from rough morphotypes. Conclusion : This characterization complements the genome data and confirms that MAC 104 behaves similarly to other MAC isolates.
Bézier projection: A unified approach for local projection and quadrature-free refinement and coarsening of NURBS and T-splines with particular application to isogeometric design and analysis

Abstract We introduce Bezier projection as an element-based local projection methodology for B-splines, NURBS, and T-splines. This new approach relies on the concept of Bezier extraction and an associated operation introduced here, spline reconstruction, enabling the use of Bezier projection in standard finite element codes. Bezier projection exhibits provably optimal convergence and yields projections that are virtually indistinguishable from global L 2 projection. Bezier projection is used to develop a unified framework for spline operations including cell subdivision and merging, degree elevation and reduction, basis roughening and smoothing, and spline reparameterization. In fact, Bezier projection provides a quadrature-free approach to refinement and coarsening of splines. In this sense, Bezier projection provides the fundamental building block for h p k r -adaptivity in isogeometric analysis.
Effects of Low-Volume Resistive Exercise on Beta-Endorphin and Cortisol Concentrations

It has been recently suggested that high and sustained lactate levels may elicit increases in peripheral B-EN concentrations (16). We have observed elevated and sustained lactate concentrations in response to a low-volume resistive exercise protocol (14) that were similar to those from other exercise protocols that produced elevated beta-endorphin (B-EN) concentrations. Thus, the purpose of the study was to determine the effects of a low-volume (21,700 J) resistive exercise repetition maximum (RM) protocol using weight machines on peripheral lactate, B-EN and Cortisol concentrations. Subjects completed 3 sets of bench press, lat-pull, leg extension, and leg curl exercise at a 10-RM load. Blood samples were collected and rating of perceived exertion (RPE, 15-point Borg scale) was assessed before exercise (- 40 and - 10 min), after each exercise, and after the exercise session (+ 35 min); blood samples were collected at 7 additional post-exercise times. RPE increased significantly throughout the exercise. Lactate concentrations rose significantly to peak at 8.54 mM at LE. B-EN and Cortisol concentrations (- 10) of 4.63 ± 0.54 pmol · l -1 and 12.09 ± 1.44 μg · dl -1 , respectively, were not significantly elevated over time. The data suggest that a low-volume resistive exercise protocol using weight machines elevates lactate concentrations without altering B-EN and Cortisol concentrations.
Scalp hair patterning as a clue to early fetal brain development.

Studies of hair follicle development and scalp hair patterning in normal persons coupled with observations of aberrant scalp hair patterning in a variety of disorders of early brain and craniofacial development are indicative of the following hypothesis: Scalp hair patterning is determined at 10 to 16 weeks of fetal life and is secondary to the growth and shape of tissues which underlie the fetal skin, especially the brain. Thus aberrant scalp hair patterning may be utilized as a clinical indicator of aberrant growth and/or shape of the early fetal brain prior to 16 weeks' gestation.
Hypothermic circulatory arrest and hypothermic perfusion for extensive disease of the thoracic and thoracoabdominal aorta.

Background: Hypothermic cardiopulmonary bypass with or without an interval of circulatory arrest has been evaluated for the treatment of complex aortic disease of the descending thoracic and thoracoabdominal aorta. Hypothermia has a protective effect on spinal cord function, and its use should reduce the incidence of paraplegia and paraparesis in traditionally high-risk patients. Experimentally, the protective effect of hypothermia has been related to amelioration of excitotoxic injury by reduction of neurotransmitter release and to inhibition of delayed apoptopic cell death.Methods: During a 12-year period, 114 patients with descending thoracic or thoracoabdominal aortic disease underwent replacement of the involved aortic segments using hypothermic cardiopulmonary bypass and intervals of circulatory arrest. The mean age of the patients was 60 years (range 22 to 79 years). Acute or chronic dissection was present in 40 patients (35%). Sixty-four patients (56%) had Crawford Types I, II, or III thoracoabdominal aneurysms.Results: The hospital mortality was 8% (9 patients). Paraplegia occured in 2 and paraparesis in 1 of the 108 patients whose lower limb function was assessed postoperatively (2.8%). None of 40 patients with aortic dissection and none of the last 81 patients in the series developed paralysis. One patient developed renal failure that required dialysis.Conclusions: Our experience with hypothermic cardiopulmonary bypass and circulatory arrest confirms that hypothermia provides substantial protection against spinal cord ischemic injury. It allows complex operations on the descending thoracic and thoracoabdominal aorta to be performed with acceptable mortality, a low incidence of renal failure, and an incidence of other complications that does not exceed that reported with other techniques.
Adaptive and incidental consequences of the alba polymorphism in an agricultural population of Colias butterflies: female size, fecundity, and differential dispersion

A sex-limited color dimorphism occurs in many populations of Colias eurytheme. Alba females exhibit different patterns of resource allocation and are less attractive than orange females. This study examines some of the consequences of these differences in terms of reproductive success and population structure in a high density agricultural population.Alba females produced more eggs than orange females on a daily basis, but the morphs did not differ in three measures of size. Spermatophore counts revealed that fresh and worn females did not differ in mating frequency between the two morphs, but very worn alba females gained more matings than very worn orange females.In two mark-release-recapture experiments, alba females exhibited longer residence times than orange females. Changes in population structure over time suggest that this was due to dispersal of orange females from the mature field. Evidence is presented that orange females emigrate in response to male harassment at high density while alba females, exposed to less harassment, remain behind. We suggest that the persistence of the polymorphism in this agricultural population is at least partially facilitated by the cyclic cutting of the alfalfa.
“A” is for airway … Also for action

Abstract [Delbridge TR, Yealy DM. "A" is for airway … also for action. Ann Emerg Med . January 2001;37:62-64.]
An oscillator-amplifier dye laser: Tuneable high powers without grating damage

Abstract An oscillator-amplifier dye laser pumped by a single giant-pulse ruby laser is described. The system allows production of a tuneable 5 MW, 30 nsec pulse without damaging the intra-cavity echelle which is used to achieve the 0.05 nm linewidth. Higher powers should be obtainable by the addition of another amplifier cell.
Interferon Regulatory Factor 3 Is Necessary for Induction of Antiviral Genes during Human Cytomegalovirus Infection

Viral infection activates interferon regulatory factor 3 (IRF3), a cofactor for the induction of interferon-stimulated genes (ISGs). The role of IRF3 in the activation of ISGs by human cytomegalovirus (HCMV) is controversial despite the fact that HCMV has consistently been shown to induce ISGs during infection of fibroblasts. To address the function of IRF3 in HCMV-mediated ISG induction, we monitored ISG expression and global gene expression in HCMV-infected cells in which IRF3 function had been depleted by small interfering RNA or blocked by dominant negative IRF3. A specific reduction of ISG induction was observed, whereas other transcripts were unaffected. We therefore conclude that IRF3 specifically regulates ISG induction during the initial phase of HCMV infection.
P21Cip1 Protects against Oxidative Stress by Suppressing ER Dependent Activation of Mitochondrial Death Pathways

Although it is well established that the cell cycle inhibitor p21 protects against genotoxic stress by preventing the replication of damaged DNA, recent studies have shown that the cytoplasmic form can also protect. It protects by delaying the loss of the antiapoptotic proteins Mcl-1 and Bcl-X(L); however, the mechanism of regulation is unknown. Utilizing hyperoxia as a model of chronic oxidative stress and DNA damage, p21 was detected in the nucleus and cytoplasm and cytoplasmic expression of p21 was sufficient for cytoprotection. p21 was enriched in a subcellular fraction containing mitochondria and endoplasmic reticulum (ER), suggesting that it may be coordinating ER and mitochondrial stress pathways. Consistent with this, p21 suppressed hyperoxic downregulation of BiP and subsequent activation of ER stress signaling, which affected Mcl-1, but not Bcl-X(L); though both inhibited hyperoxic cell death. Taken together, these data show that p21 integrates the DNA damage response with ER stress signaling, which then regulates mitochondrial death pathways during chronic genotoxic stress.
The effect of subtype-selective muscarinic receptor antagonists on the cholinergic current in motoneurons of the lobster cardiac ganglion.

Abstract Muscarinic agonists evoke a voltage-dependent inward current in motoneurons of the lobster cardiac ganglion. In this study, a number of drugs, known to show muscarinic receptor subtype selectivity in mammals, were used to determine the pharmacological profile of the muscarinic receptor on lobster motoneurons. The neurons were held under voltage-clamp, and various concentrations of the antagonists were applied in the presence of 1 mM methacholine. From competition curves plotting agonist-induced current against antagonist concentration, the inhibitor affinity constant and the slope factor were determined. The rank order of potencies of antagonists having an effect was: atropine > pirenzepine > 4-DAMP > methoctramine > HHSiD = (R)-HHD > (S)-HHD. Neither AF-DX 116 nor gallamine were effective at concentrations as high as 10 mM. The M 1 -selective agonist McN-A-343 had no effect. Although this crustacean muscarinic receptor resembles the mammalian M 1 muscarinic receptor because of its relatively high affinity for pirenzepine, the rank order of other subtype-specific antagonist does not otherwise resembles that of any of the pharmacologically defined muscarinic receptors in mammals. It may be preferable, therefore, to use a term such as ‘pirenzepine-sensitive’ muscarinic receptor rather than M 1 or ‘M 1 -like’ for invertebrte muscarinic receptors with pharmacological characteristics like those reported here.
Memory Characteristics Of Two Dimensional Movement Information

Abstract Two experiments examined the reproduction accuracy and retention characteristics of two-dimensional movement information. Distance, location, and combined location plus distance groups were examined under three retention intervals. The results of both experiments generally revealed that distance cues were maintained over a 15-second rest interval and subject to decay when interpolated activity was introduced. In contrast, recall accuracy for both the location group and the location plus distance group decayed during the rest interval. Following the presentation of interpolated activity, the location group exhibited no further decrement while the location plus distance group continued to demonstrate a decay in accuracy. These results imply a differential access to central processing for the two sources of movement information. That is, contrary to the results of previous studies utilizing one-dimensional tasks, two-dimensional distance cues appear to be centrally processed while location cues are ...
Observation of single-chain scattering from homopolymer blended with a triblock copolymer

A small-angle neutron scattering method has been developed to determine the chain conformation of homopolymer chains dispersed in a block copolymer matrix. Two contrast matching techniques are used to achieve this result and are demonstrated for a system based on a styrene-hydrogenated butadiene-styrene triblock copolymer and a hydrogenated butadiene homo-polymer. Composition matching uses a blend of labeled and unlabeled molecules to match the scattering density of another component. Phase matching requires a block copolymer which has been synthesized such that the scattering densities of the blocks are equal. This polymer provides a transparent matrix in which a composition-matched blend of homopolymer can be dispersed to isolate the single-chain scattering function of the homopolymer chains.
Effects of Soil Application of Different Biochars on Selected Soil Chemical Properties

An incubation study was conducted to determine if biochars created using different feedstocks and under different reactor conditions would differentially influence specific soil chemical properties. A Nicollet surface soil (fine-loamy, mixed, superactive, mesic Aquic Hapludoll) was mixed with 17 different biochars and a nitrogen fertilizer (urea). The biochars were created with different feedstocks and different reactor conditions. Soil tests for total nitrogen (N), total organic carbon (C), ammonium N (NH4 +-N), and nitrate N (NO3 −-N) were run. Results show that the feedstock used to create the biochar influenced how it affected the specific soil chemical properties measured. Results also suggest that the conditions within the reactor influence how the biochar will affect the soil chemical properties measured.
Computed tomography demonstration of distal femoral (trochlear) articular groove: a normal variant.

In computed tomography of the skeleton, as in other radiologic modalities, recognition of normal skeletal variants is essential for defining the extent and type of injury or neoplasm. Computed tomography findings, because of the unique use of cross-sectional anatomy, must be carefully studied to avoid labeling a normal variant as an abnormal entity. We describe here an observation of a normal variant-distal femoral, anterior articular (trochlear) groove-found in a patient with an osteochondral fracture and loose intra-articular bony fragment.
Response of legumes and cereals to phosphorus in solution culture

Abstract Phosphorus deficiency is one of the Important growth limiting factors in crop production in many regions of the world. The objective of this study was to evaluate responses of alfalfa (Medicago sativa L.), red clover (Trifoilum pratense L.), common bean (Phaseolus vulgaris L.), wheat (Triticum aestivum L.) and rice (Oryza sativa L.) to concentrations of P in nutrient solution. The P treatments applied were 5, 50, 100, 200 and 400 μM P. All crop species significantly responded to an increase in external P concentrations. The optimum P concentration for maximum growth varied with crop species, but it was higher for legumes than for cereals. Rice needs minimum as red clover maximum P concentration for maximum growth in nutrient solution as compared to other crops species. Concentrations of K, Zn and Mn were significantly affected in all crop species with P addition. Suggesting positive effects of P in ameliorating Mn toxicity if this element is present in growth medium. Increasing concentrations of ...
The backscattering cross section of a cone-sphere

The metallic cone-sphere is the prototype for many low cross-sectional shapes, and in recent years it has been receiving an increasing amount of attention. In spite of the simplicity of its mathematical form, it is still a shape for which no exact solution of the boundary-value problem is available, and to calculate the cross section we must rely on approximate methods with such refinements and extensions as experimental data may demand. We here present some new data for both the backscattered and the surface fields at nose-on incidence and deduce therefrom a modification to the accepted theory sufficient to explain the results.
Medical Technology in the United States and Canada: Where Are We Going?

U.S. and Canadian policies concerning medical technology acquisition and diffusion are compared. Healthcare resources are allocated primarily through insurance incentives in the U.S. and through budget controls in Canada. Technological acquisitions, a small component of healthcare expenditures, are influenced by industry competition in the U.S., and by U.S. marketing in Canada. Healthcare utilization, a large component of expenditures, has caused similar resource allocation issues in both countries. Both countries are becoming more similar in their healthcare policies. Canada is becoming more privatized in financing healthcare services, and the U.S. is moving toward more conservative medicine. Both countries face similar challenges in technological acquisition and diffusion. Care must be taken that administrative hurdles do not alter the stream of returns to technology so that the R&D of beneficial technologies will be encouraged. Also, evaluation methods must objectively measure the economic costs and be...
Genetically engineered excitable cardiac myofibroblasts coupled to cardiomyocytes rescue normal propagation and reduce arrhythmia complexity in heterocellular monolayers.

RATIONALE AND OBJECTIVE The use of genetic engineering of unexcitable cells to enable expression of gap junctions and inward rectifier potassium channels has suggested that cell therapies aimed at establishing electrical coupling of unexcitable donor cells to host cardiomyocytes may be arrhythmogenic. Whether similar considerations apply when the donor cells are electrically excitable has not been investigated. Here we tested the hypothesis that adenoviral transfer of genes coding Kir2.1 (I(K1)), Na(V)1.5 (I(Na)) and connexin-43 (Cx43) proteins into neonatal rat ventricular myofibroblasts (NRVF) will convert them into fully excitable cells, rescue rapid conduction velocity (CV) and reduce the incidence of complex reentry arrhythmias in an in vitro model. METHODS AND RESULTS We used adenoviral (Ad-) constructs encoding Kir2.1, Na(V)1.5 and Cx43 in NRVF. In single NRVF, Ad-Kir2.1 or Ad-Na(V)1.5 infection enabled us to regulate the densities of I(K1) and I(Na), respectively. At varying MOI ratios of 10/10, 5/10 and 5/20, NRVF co-infected with Ad-Kir2.1+ Na(V)1.5 were hyperpolarized and generated action potentials (APs) with upstroke velocities >100 V/s. However, when forming monolayers only the addition of Ad-Cx43 made the excitable NRVF capable of conducting electrical impulses (CV = 20.71±0.79 cm/s). When genetically engineered excitable NRVF overexpressing Kir2.1, Na(V)1.5 and Cx43 were used to replace normal NRVF in heterocellular monolayers that included neonatal rat ventricular myocytes (NRVM), CV was significantly increased (27.59±0.76 cm/s vs. 21.18±0.65 cm/s, p<0.05), reaching values similar to those of pure myocytes monolayers (27.27±0.72 cm/s). Moreover, during reentry, propagation was faster and more organized, with a significantly lower number of wavebreaks in heterocellular monolayers formed by excitable compared with unexcitable NRVF. CONCLUSION Viral transfer of genes coding Kir2.1, Na(V)1.5 and Cx43 to cardiac myofibroblasts endows them with the ability to generate and propagate APs. The results provide proof of concept that cell therapies with excitable donor cells increase safety and reduce arrhythmogenic potential.
Age-related changes in lipofuscin-associated fluorescent substances in the adult male housefly, Musca domestica.

Fluorescent material consisting of Schiff-base products increased with age in the chloroform-methanol extracts of the adult housefly, Musca domestica. The autofluorescent granules observed in tissue sections are identical to lipofuscin. The fluorescent spectra of the tissue extracts had an excitation maximum of 365 nm and an emission maximum of 435 nm. The fluorescent intensity of Eu (III) added to the chloroform-methanol extracts increased due to the energy transfer from the Schiff-base products. The highest concentration of the fluorescent substances occured in the head, however, the autofluorescent granules observed by fluorescence microscopy were most numerous in the abdominal tissues.
COUNTERIMMUNELECTROPHORESIS IN HEMOPHILUS INFLUENZAE TYPE B EPIGLOTTITIS AND PERICARDITIS

Counterimmunelectrophoresis (CIE) was used to detect polyribophosphate (PRP), the capsular polysaccharide antigen of Hemophilus influenzae type b (H.flu.b), in sera of patients with H.flu.b epiglottitis and sera and pericardial fluids of patients with H.flu.b pericarditis. CIE was performed for 30 mins. at 30 milliamps using (NH4)2 SO4 precipitated rabbit antisera and Hyland agar gel plates. The sera of 7 patients with H.flu.b epiglottitis were tested prior to IV Ampicillin therapy. Immunoprecipitin bands became visible in 3 specimens after cooling for 30 mins. and in a fourth after cooling for 10 hrs. Three sera contained 5 ng of PRP per ml, while the fourth contained between 2.5 and 5 ng of PRP per ml, a quantity which represents the lower limits of sensitivity for this technique. The brief course of epiglottitis prior to therapy may explain the small amount of PRP produced. In contrast, pericardial fluids and sera of 3 patients with H.flu.b pericarditis were markedly positive. Two pericardial fluids were quantitated. The first contained 5.85×105ng of PRP per ml and the second contained 19×105 ng of PRP per ml. The pericardial sac may function as a depot for large amounts of antigen.
The effect of pregnancy on production of maternal endogenous hematopoietic stem cells

Abstract Fetal microchimerism refers to the presence of fetal cells in maternal blood and tissues during pregnancy. This microchimerism may result from trafficking of fetal and maternal blood across the placenta during pregnancy. Physiological changes in the maternal blood cellular milieu are also recognized during pregnancy and in the early postpartum period. Earlier studies showed that maternal blood contains CD34 + hematopoietic stem cells (HSCs) that bear paternal genetic markers or male phenotype, suggesting that these cells circulated to the mother from male fetuses during pregnancy. Other studies showed that these maternal HSCs have significantly lower expansion potential than their fetal counterparts. We have recently shown increased percentages of CD34 + HSCs in peripheral blood of pregnant and parous women. Herein, we hypothesize that pregnancy stimulates the production of endogenous CD34 + HSCs of maternal origin, a phenomenon which potentially could favor postpartum regenerative capacity.
Quantitative trait loci mapping of seed colour, hairy leaf, seedling anthocyanin, leaf chlorosis and days to flowering in F2 population of Brassica rapa L.

A diversity arrays technology (DArT) map was constructed to identify quantitative trait loci (QTL) affecting seed colour, hairy leaf, seedling anthocyanin, leaf chlorosis and days to flowering in Brassica rapa using a F2 population from a cross between two parents with contrasting traits. Two genes with dominant epistatic interaction were responsible for seed colour. One major dominant gene controls the hairy leaf trait. Seedling anthocyanin was controlled by a major single dominant gene. The parents did not exhibit leaf chlorosis; however, 32% F2 plants showed leaf chlorosis in the population. A distorted segregation was observed for days to flowering in the F2 population. A linkage map was constructed with 376 DArT markers distributed over 12 linkage groups covering 579.7 cM. The DArT markers were assigned on different chromosomes of B. rapa using B. rapa genome sequences and DArT consensus map of B. napus. Two QTL (RSC1-2 and RSC12-56) located on chromosome A8 and chromosome A9 were identified for seed colour, which explained 19.4% and 18.2% of the phenotypic variation, respectively. The seed colour marker located in the ortholog to Arabidopsis thaliana Transparent Testa2 (AtTT2). Two QTL RLH6-0 and RLH9-16 were identified for hairy leaf, which explained 31.6% and 20.7% phenotypic variation, respectively. A single QTL (RSAn-12-157) on chromosome A7, which explained 12.8% of phenotypic variation was detected for seedling anthocyanin. The seedling anthocyanin marker is found within the A. thaliana Transparent Testa12 (AtTT12) ortholog. A QTL (RLC6-04) for leaf chlorosis was identified, which explained 55.3% of phenotypic variation. QTL for hairy leaf and leaf chlorosis were located 0–4 cM apart on the same chromosome A1. A single QTL (RDF-10-0) for days to flowering was identified, which explained 21.4% phenotypic variation.
Abstinence Memorable Message Narratives: A New Exploratory Research Study Into Young Adult Sexual Narratives

Abstinence for most adolescent-aged college students relates to several factors, including strong religious beliefs, an aversion to taking risks, high career expectations, or limited attractiveness. Young adults receive hundreds of messages from various sources; therefore, understanding their memorable sexual messages is essential. This exploratory research uses an interpretive method to unravel the memorable sexual narratives of 65 virgin respondents. Findings yield two primary themes: involuntary abstinence, and conscious abstinence, which demonstrate that messages of abstinence are important yet often imbue punitive internal attitudes and beliefs derived from mainstream media and peer relationships. The article concludes with a recommendation for health practitioners and communication scholars to create positive open spaces where young adults can discuss sexuality, sexual relationships, and sexual behaviors. Additionally, understanding stigmas related to abstinence helps reframe normative sex communication messages and promote constructive short- and long-term sexual health behaviors.
SEMI-INSULATING BULK GAAS AS A SEMICONDUCTOR THERMAL-NEUTRON IMAGING DEVICE

Abstract Thermal-neutron Schottky barrier detector arrays fabricated from semi-insulating bulk GaAs are presently being tested. The devices use a film of 10B to convert the incident thermal-neutron field into α particles and lithium ions, either of which interact in the detector. Bulk GaAs Schottky barrier detectors are relatively radiation hard to thermal neutrons and γ rays and have shown reasonably good energy resolution for α particles. Additionally, reverse biased radiation detectors fabricated from semi-insulating bulk GaAs have been shown to have truncated electric field distributions, resulting in the formation of a high field active region and a considerably lower field dead region. The device is sensitive only to electron-hole pairs excited in the high field region, thus the truncated field effect is advantageous as an inherent γ-ray discrimination feature for neutron detectors. Preliminary results show no indication of device degradation after over 2400 hr in a thermal-neutron beam from a reactor. Images have been formed of 1, 1.5, and 2 mm holes and crosses from 2 mm thick Cd templates.
Applications of continuous-time stochastic methods to models of endogenous economic growth

Abstract This paper develops a continuous-time general equilibrium stochastic growth model. After deriving the equilibrium, the model is used to analyze the determinants of the equilibrium growth rate. Equilibrium asset pricing and optimal tax issues are also considered. The paper concludes by indicating how the analysis can be extended to include: (i) money, (ii) adjustment costs in investment; (iii) utility-enhancing and productive government expenditure; (iv) applications to international economics.
Correlation of Pliocene and Pleistocene tephra layers between the Turkana Basin of East Africa and the Gulf of Aden

Abstract Electron-microprobe analyses of glass shards from volcanic ash in Pliocene and Pleistocene deep-sea sediments in the Gulf of Aden and the Somali Basin demonstrate that most of the tephra layers correlate with tephra layers known on land in the Turkana Basin of northern Kenya and southern Ethiopia. Previous correlations are reviewed, and new correlations proposed. Together these data provide correlations between the deep-sea cores, and to the land-based sections at eight levels ranging in age from about 4 to 0.7 Ma. Specifically, we correlate the Moiti Tuff (⩽4.1 Ma) with a tephra layer at 188.6 m depth in DSDP hole 231 and with a tephra layer at 150 m depth in DSDP hole 241, the Wargolo Tuff with a tephra layer at 179.7 m in DSDP Hole 231 and with a tephra layer at 155.3 m depth in DSDP Hole 232, the Lomogol Tuff (defined here) with a tephra layer at 165 m in DSDP Hole 232A, the Lokochot Tuff with a tephra layer at 140.1 m depth in DSDP Hole 232, the Tulu Bor Tuff with a tephra layer at 160.8 m depth in DSDP Hole 231, the Kokiselei Tuff with a tephra layer at 120 m depth in DSDP Hole 231 and with a tephra layer at 90.3 m depth in DSDP Hole 232, the Silbo Tuff (0.74 Ma) with a tephra layer at 35.5 m depth in DSDP Hole 231 and possibly with a tephra layer at 10.9 m depth in DSDP Hole 241. We also present analyses of other tephra from the deep sea cores for which correlative units on land are not yet known. The correlated tephra layers provide eight chronostratigraphic horizons that make it possible to temporally correlate paleoecological and paleoclimatic data between the terrestrial and deep-sea sites. Such correlations may make it possible to interpret faunal evolution in the Lake Turkana basin and other sites in East Africa within a broader regional or global paleoclimatic context.
The Long Voyage Home—Begun

later. Applying for one's first permanent full-time academic position following completion of the Ph.D. is terribly important and has great potential for error. Most of us aren't exactly sure what we want in a position or an institution beyond "something good," and the experience is not repeated. It is not such a bad thing to get it as close to right as possible the first time. My own experience, casual observation of graduate colleagues, and conversations with recently appointed assistant professors suggest that a substantial mythology surrounds the beliefs held by graduate students about the process. Sources of these beliefs are several: the inevitable naivete
Student use of test-wiseness strategies in solving multiple-choice chemistry examinations

Test-wiseness strategies used by 11 general chemistry students as they answered a 15-item multiple-choice examination were investigated using a think-aloud technique. A coding scheme based on a published classification of test-wiseness strategies was developed and transcripts were coded using the scheme. Finally, the frequency of each type of strategy that appeared was tabulated. The most common strategies were those that did not compromise the validity of the examination: error avoidance, elimination of incorrect responses, checking responses, and optimal time management. A less common set of strategies helped students gain points beyond those for specific content knowledge. These include deductive reasoning strategies such as similar options, opposing options, absurd options, and an umbrella term. This evidence further supports the idea that test-wiseness strategies are independent of subject area. Excerpts from the transcripts illustrate the strategies employed and support the idea that students be required to write justifications for responses to multiple-choice items (Tamir, 1990).
A magnetically levitated fine motion wrist: kinematics, dynamics and control

Reference is made to a previous paper by the authors and A.P. Allan (1988) in which the motivation for and the design of a magnetically levitated robot wrist have been described. The kinematic and dynamic transformations that are required for the control of this 'magic' wrist are presented. The wrist's dynamics are formulated in terms of the Euler quaternion, and the advantages of such a formulation, as well as control schemes based on it, are discussed. The prototype magic wrist was successfully controlled with a simple PD (proportional differential) feedback compensator, both in position and compliance modes. The result obtained, including synthesis of several mechanisms, establish the feasibility of the approach proposed in the original paper. >
The effect of ovarian steroidogenesis on ovulation and fertilizability in the in vitro perfused rabbit ovary.

The effects of aminoglutethimide phosphate (AGP) on ovulation, ovum maturation, fertilizability, and steroid production were studied with the use of an isolated perfused rabbit ovary preparation. AGP (10’ or 10� M) was added to the perfusate of one ovary. The contralateral control ovary was perfused in medium alone. Thirty minutes later human chorionic gonadotropin (hCG) (50 JU) was added to the perfusate of all ovaries. No difference was observed in time of ovulation or ovulatory efficiency between controls and AGPtreated ovaries. The degree of ovum maturity and degeneration was also comparable in the two groups. Progesterone and estradiol production were significantly reduced by A GP treatment. A second experiment examined fertilizability of ova ovulated in vitro after perfusion with i0� M AGP. A GP significantly reduced the rate of normal fertilization as observed 12 h after insemination. The percentage of inseminated ova with evidence of degeneration was greater in ova from AGP-treated ovaries than in those from controls, however, this difference was not significant. The study indicates that AGP affects neither hCG-induced ovulation nor meiotic resumption; however, fertilizability of ova from ovaries treated with A GP is impaired. These data suggest that the intrafollicular steroid environment may participate in cytoplasmic maturation of ovulated ova.
Structural Determinants of the Interaction between the TpsA and TpsB Proteins in the Haemophilus influenzae HMW1 Two-Partner Secretion System

ABSTRACT The two-partner secretion (TPS) pathway in Gram-negative bacteria consists of a TpsA exoprotein and a cognate TpsB outer membrane pore-forming translocator protein. Previous work has demonstrated that the TpsA protein contains an N-terminal TPS domain that plays an important role in targeting the TpsB protein and is required for secretion. The nontypeable Haemophilus influenzae HMW1 and HMW2 adhesins are homologous proteins that are prototype TpsA proteins and are secreted by the HMW1B and HMW2B TpsB proteins. In the present study, we sought to define the structural determinants of HMW1 interaction with HMW1B during the transport process and while anchored to the bacterial surface. Modeling of HMW1B revealed an N-terminal periplasmic region that contains two polypeptide transport-associated (POTRA) domains and a C-terminal membrane-localized region that forms a pore. Biochemical studies demonstrated that HMW1 engages HMW1B via interaction between the HMW1 TPS domain and the HMW1B periplasmic region, specifically, the predicted POTRA1 and POTRA2 domains. Subsequently, HMW1 is shuttled to the HMW1B pore, facilitated by the N-terminal region, the middle region, and the NPNG motif in the HMW1 TPS domain. Additional analysis revealed that the interaction between HMW1 and HMW1B is highly specific and is dependent upon the POTRA domains and the pore-forming domain of HMW1B. Further studies established that tethering of HMW1 to the surface-exposed region of HMW1B is dependent upon the external loops of HMW1B formed by residues 267 to 283 and residues 324 to 330. These observations may have broad relevance to proteins secreted by the TPS pathway. IMPORTANCE Secretion of HMW1 involves a recognition event between the extended form of the HMW1 propiece and the HMW1B POTRA domains. Our results identify specific interactions between the HMW1 propiece and the periplasmic HMW1B POTRA domains. The results also suggest that the process of HMW1 translocation involves at least two discrete steps, including initial interaction between the HMW1 propiece and the HMW1B POTRA domains and then a separate translocation event. We have also discovered that the HMW1B pore itself appears to influence the translocation process. These observations extend our knowledge of the two-partner secretion system and may be broadly relevant to other proteins secreted by the TPS pathway.