cssi/SciSciGPT-SciSciNet huggingface dataset:
Mechanisms governing activity-dependent synaptic pruning in the developing mammalian CNS

Almost 60 years have passed since the initial discovery by Hubel and Wiesel that changes in neuronal activity can elicit developmental rewiring of the central nervous system (CNS). Over this period, we have gained a more comprehensive picture of how both spontaneous neural activity and sensory experience-induced changes in neuronal activity guide CNS circuit development. Here we review activity-dependent synaptic pruning in the mammalian CNS, which we define as the removal of a subset of synapses, while others are maintained, in response to changes in neural activity in the developing nervous system. We discuss the mounting evidence that immune and cell-death molecules are important mechanistic links by which changes in neural activity guide the pruning of specific synapses, emphasizing the role of glial cells in this process. Finally, we discuss how these developmental pruning programmes may go awry in neurodevelopmental disorders of the human CNS, focusing on autism spectrum disorder and schizophrenia. Together, our aim is to give an overview of how the field of activity-dependent pruning research has evolved, led to exciting new questions and guided the identification of new, therapeutically relevant mechanisms that result in aberrant circuit development in neurodevelopmental disorders.
Spatio-Temporally Modulated Metamaterials

In this talk, we discuss the opportunities and potentials of metamaterials in which their constituent elements are modulated in space and time with tailored patterns, or abruptly change in space-time, in order to overcome the constraints of passive, linear, time-invariant materials. We will discuss nonreciprocal and parametric phenomena enabled by these spatiotemporally modulated metamaterials, and emphasize the challenges in efficiently modeling their responses with analytical and numerical techniques. We will also survey several applications of this platform from radio-wave and mm-wave technology to classical and quantum photonics.
Impact of Video Describing Cataract Surgical Simulator Training on Patients' Perceptions of Resident Involvement in Cataract Surgery

Purpose The aim of this article is to investigate the impact of a 1-minute video describing resident training with a cataract surgical simulator on patients' perceptions regarding resident involvement in cataract surgery and to identify factors associated with patient willingness to have cataract surgery performed by a resident. Design Cross-sectional survey. Methods An anonymous Likert-style survey was conducted among 430 consecutive adult patients who presented for eye examination at the Penn State Health Eye Center. The survey included questions regarding demographics, understanding of the medical training hierarchy, and patient willingness to have a resident perform their cataract surgery. There were six questions regarding patient willingness to have residents perform their cataract surgery and the second question in this set informs the patient that residents are supervised by an experienced cataract surgeon. Patients were randomly assigned to one of two groups: patients in Group 1 completed the survey only, while patients in Group 2 watched a 1-minute video describing resident training with a cataract surgical simulator prior to completing the survey. Results Four hundred fourteen of the 430 patients (96.3%) completed the survey. Overall, 24.7% (n = 102) of respondents expressed willingness to allow an ophthalmology resident to perform their cataract surgery, and that proportion increased to 54.0% (n = 223) if the patient was informed that the resident would be supervised by an experienced cataract surgeon. Patients in Group 2 were twice as likely compared with patients in Group 1 to express willingness to allow an ophthalmology resident to perform their cataract surgery (odds ratio 1.92 [1.18–3.11], p = 0.009). Conclusions A thorough informed consent process including information regarding attending supervision and a brief video detailing resident training with a cataract surgery simulator may increase patient willingness to allow resident participation in cataract surgery.
Diffusion control of quartz and forsterite dissolution rates

Abstract An established engineering model is used to identify conditions where diffusion controls the dissolution of quartz and forsterite in packed beds. The model shows that diffusion control is favored at low advection flux, large grain size, high temperature, and high pH (if the reaction consumes H+). Quartz dissolution is chemical reaction controlled for most geochemically reasonable combinations of temperature, grain size, and flow rate. On the other hand, forsterite dissolution rates can be diffusion controlled for typical advection fluxes, grain sizes, temperatures, and pH’s. The apparent activation energy for diffusion-controlled reactions in a packed bed is much higher than the
The mechanism of dextransucrase action. Direction of dextran biosynthesis.

Abstract The mechanism for the biosynthesis of dextran by dextransucrase from Leuconostoc mesenteroides NRRL-B512F has been studied. Dextransucrase attached to cells and dextransucrase insolubilized on Bio-Gel beads have been obtained. It was found that these forms become labeled when incubated with a pulse of [ 14 C]sucrose. The label can be released from cells and from Bio-Gel by adjusting the pH to 2 and heating to 95 °C for 10 min. Two types of labeled carbohydrates were found to be released, glucose and dextran. The direction of the biosynthesis was determined by pulse and chase experiments with [ 14 C]sucrose. The labeled dextran was isolated, reduced, and acid hydrolyzed. The hydrolytic products, glucose and sorbitol, were separated by paper chromatography, and their radioactivities were determined. The ratio of the labeled sorbitol to labeled glucose for the pulse of Bio-Gel-dextransucrase was 1:1 and for the chase 1:100. It was concluded that dextran is biosynthesized by the transfer of glucose from sucrose to the reducing end of the growing dextran chain. This was confirmed by the hydrolysis of pulsed dextran by glycoamylase. The total radioactivity in the residual dextran did not change during the hydrolysis and labeled glucose could not be detected. It is proposed that dextransucrase forms an enzymatically active covalent complex with glucose and dextran and that the glucose is inserted between the enzyme and the dextran by a nucleophilic attack of the C 6 —OH of glucose onto C 1 of the dextran forming an α-1 → 6 glucosidic bond. This releases one of the nucleophilic groups at the active site which attacks sucrose to give an enzyme-glucosyl complex. The C 6 —OH of this glucose then repeats the process of attacking C 1 of dextran. Dextran is built up by extrusion from the enzyme when glucose units are transferred from sucrose to the active site and inserted between the enzyme and the reducing end of the dextran polymer.
‘For the Good of My Country’: A Study in Public Spirit and Public Service

This chapter will deal primarily with Kames’s activities and endeavors as a member of two national planning and promotional boards which played a most important role in the economic transformation of Scotland that occurred during the middle and latter part of the eighteenth century.
Teaching Ethics Using Tax Evasion Survey Data as a Case Study

This paper briefly discusses the three views that have emerged over the centuries on the ethics of tax evasion, then summarizes the results of several opinion surveys that were conducted on the topic. The paper concludes with a discussion of how these study results may be used in the classroom.
Interactive intermediates are formed during the urea unfolding of rhodanese.

Abstract Structural transitions have been studied on the pathway for urea denaturation of rhodanese. Unlike guanidinium hydrochloride, urea gives no visible precipitation. Increasing urea concentrations cause a transition in which the enzyme activity is completely lost by 4.5 M urea, and there is a shift of the intrinsic fluorescence maximum from 335 nm for the native enzyme to 350 nm. There is a maximum exposure of organized hydrophobic surfaces at 4.5 M urea as reported by the fluorescence of 1,1'-bi(4-anilino)naphthalene-5,5'-disulfonic acid. Above 4.5 M urea, this probe reports the progressive loss of organized hydrophobic surfaces. The polarization of the intrinsic fluorescence falls with increasing urea concentrations in a complex transition showing that rhodanese flexibility increases in at least two phases. Rhodanese becomes increasingly susceptible to digestion by subtilisin between 3.5 and 4.5 M urea, giving rise to large fragments. At urea concentrations > 5 M, rhodanese is completely digested. There is a small increase in the rate of sulfhydryl accessibility between 3.5 and 4.5 M urea, but there is a large increase in the sulfhydryl accessibility above 4.5 M urea. Dimethyl suberimidate cross-linking shows the presence of associated species in 3-5 M urea, but there are few cross-linkable species at lower or higher urea concentrations. These results are consistent with a model in which urea unfolding of rhodanese is associated with the initial production of a species having organized regions of structure with exposed hydrophobic surfaces separated by flexible elements.
Macromolecular characterization of muscle membranes. I. Proteins and sialic acid of normal and denervated muscle.

Abstract Two major membrane fractions have been isolated from denervated and contralateral limb control rat muscle by a subcellular fractionation technique involving lithium bromide and potassium chloride extraction and differential and density gradient centrifugation. Membranes isolated from the initial nuclear pellet (Fraction I) contained Na+K+(Mg++)ATPase (20 µ moles of Pi per hour per mg), sialic acid (24 nmoles per mg), and Ca++/Mg++ATPase (19 µmoles of Pi per hour per mg). With subfractionation of Fraction I the membranes enriched in Na+K+(Mg++)ATPase and sialic acid (IMl) also had the highest specific activity of membrane protein iodination using extracellular lactoperoxidase. These membrane subfractions were separated from ones containing Ca++/ Mg++ATPase activity (IMh). Membranes isolated from the post mitochondrial supernatant (Fraction II) contained Ca++/Mg++ATPase (22 µmoles of Pi per hour per mg), Na+K+(Mg++)ATPase (5 µmoles of Pi per hour per mg), and sialic acid (10 nmoles per mg). With further subfractionation the Ca++/Mg++ATPase containing membranes (IIMm and IIMh) were separated from those most accessible to iodination by extracellular lactoperoxidase and containing Na+K+(Mg++)ATPase and sialic acid (IIMl and IIL). Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed different protein profiles for Fractions I and II with polypeptide molecular weights ranging from 20,000 to 200,000. Both subfractions IMl and IIMl contained a single major glycoprotein species with an apparent molecular weight of approximately 110,000. These data would suggest that both lighter subfractions (IMl and IIMl) derived from the nuclear pellet (Fraction I) and the postmitochondrial supernatant (Fraction II), respectively, were enriched in surface membranes. The heavier subfraction (IIMh) from the postmitochondrial supernatant was enriched in membranes derived from sarcoplasmic reticulum. Following 1 week of denervation no change was observed in either electron micrographs or sodium dodecyl sulfate polyacrylamide gels of the membrane fractions. The ATPase and sialic acid of Fraction I remained unaltered while a 2-fold increase was noted in the Ca++/Mg++ATPase (51 µmoles of Pi per hour per mg) of heavier membranes of Fraction II and sialic acid (20 nmoles per mg) of lighter membranes of Fraction II.
The Role of H2 Molecules in Cosmological Structure Formation

We review the relevance of H2 molecules for structure formation in cosmology. Molecules are important at high redshifts, when the first collapsed structures appear with typical temperatures of a few hundred Kelvin. In these chemically pristine clouds, radiative cooling is dominated H2 molecules. As a result, H2 ``astro-chemistry'' is likely to determine the epoch when the first astrophysical objects appear. We summarize results of recent three-dimensional simulations. A discussion of the effects of feedback, and implications for the reionization of the universe is also given.
Selection of Relevant Species

It is important to select a relevant species for conducting safety assessment studies to mimic putative interpatient treatment differences in test article responsiveness and understand the rank order pharmacologic sensitivity of the relevant common laboratory animal species. Appropriate selection of a pharmacologically relevant species will also enable identification of factors that affect the therapeutic index of biopharmaceutical. This article discusses various experimental approaches used to select the relevant species for conduct of toxicology studies for biopharmaceuticals and advances made in scientific approaches to facilitate this process. Keywords: species selection; biologics; toxicology studies; in vivo pharmacodynamic effect; transcript profiling; in silico analysis
Structure-function and pathogenesis studies of Streptococcus pyogenes extracellular cysteine protease

Replacement of the single cysteine residue (C192) with serine in the Streptococcus pyogenes extracellular cysteine protease (SCP) prevented auto-catalytic processing of the 40-kDa zymogen to the 28-kDa mature form and eliminated proteolytic activity. SCP incubated with human endothelial cells induced a time- and concentration-dependent increase in a 66-kDa gelatinase/type IV collagenase in culture supernatants. Activation of this gelatinase/collagenase may contribute to endothelial cell damage, tissue destruction, and hemodynamic derangement observed in some patients with severe, invasive S. pyogenes infection.
A delta gap source for locally corrected Nyström discretized integral equations

A delta gap source formulation suitable for use in locally corrected Nystrom (LCN) discretizations of electric field integral equations is presented. The delta-gap is applied to an edge (or group of edges) between a set of faces. Due to the point-sampling used in the LCN method, the delta gap effect is distributed across the faces shared by the source edges. The LCN delta gap is validated using results from the moment method.
Patterns and mechanisms of lumbar injuries associated with lap seat belts

Of twenty-four lumbar-spine fractures observed in seat-belt wearers, twenty showed an Unusual and consistent pattern of injury characterized by separation of the posterior elements without the usually expected decrease in height of the anterior portion of the vertebral bodies. It is suggested that tension stress is primarily responsible for the unusual patterns seen in these injuries. A mechanism by which large tension forces may be brought to bear on the lumbar spine has been described. Although the lap seat belt is instrumental in producing the lesion described, this report is in no way an indictment of the lap-type seat belt. All of the lesions studied were products of very severe collisions. We are convinced that if these individuals had not been wearing seat belts, they would not have survived. It is likely that these injuries might not have occurred if the patients had been wearing shoulder-type seat belts. The possibility that the shoulder harness might focus similar stress at the cervicothoracic junction with production of a far more serious spine injury remains a matter of conjecture.
Initial liquid metal magnetohydrodynamic thin film flow experiments in the MeGA-loop facility at UCLA

Abstract Free surface, thin film flows of liquid metal were investigated experimentally in the presence of a coplanar magnetic field. This investigation was performed in a new magnetohydrodynamic (MHD) flow facility, the McGA-loop, utilizing a low melting temperature lead-bismuth alloy as the working metal. Owing to the relatively low magnetic field produced by the present field coil system, the ordinary hydrodynamic and low MHD interaction regimes only were investigated. At the high flow speeds necessary for self cooling, the importance of a well designed and constructed channel becomes obvious. MHD drag, increasing the film height, is observed as Haβ2 becomes greater than unity. Partial MHD laminarization of the turbulent film flows is observed when Haβ/Re > 0.002, but fully laminar flow was not reached. Suggestions for facility upgrades to achieve greater MHD interaction are presented in the context of these initial results.
Comparing Several Human and Computer-Based Methods for Scoring Concept Maps and Essays:

This article reports the results of an investigation of the convergent criterion-related validity of two computer-based tools for scoring concept maps and essays as part of the ongoing formative evaluation of these tools. In pairs, participants researched a science topic online and created a concept map of the topic. Later, participants individually wrote a short essay from their concept map. The concept maps and essays were scored by the computer-based tools and by human raters using rubrics. Computer-based concept map scores were a very good measure of the qualitative aspects of the concept maps (r = 0.84) and were an adequate measure of the quantitative aspects (r = 0.65). Also, the computer-based essay scores were an adequate measure of essay content (r = 0.71). If computer-based approaches for scoring concept maps and essays can provide a valid, low-cost, easy to use, and easy to interpret measure of students' content knowledge, then these approaches will likely gain rapid acceptance by teachers at a...
Analysis of Pathway Activity in Primary Tumors and NCI60 Cell Lines Using Gene Expression Profiling Data

To determine cancer pathway activities in nine types of primary tumors and NCI60 cell lines, we applied an in silico approach by examining gene signatures reflective of consequent pathway activation using gene expression data. Supervised learning approaches predicted that the Ras pathway is active in ~70% of lung adenocarcinomas but inactive in most squamous cell carcinomas, pulmonary carcinoids, and small cell lung carcinomas. In contrast, the TGF- β , TNF- α , Src, Myc, E2F3, and β -catenin pathways are inactive in lung adenocarcinomas. We predicted an active Ras, Myc, Src, and/or E2F3 pathway in significant percentages of breast cancer, colorectal carcinoma, and gliomas. Our results also suggest that Ras may be the most prevailing oncogenic pathway. Additionally, many NCI60 cell lines exhibited a gene signature indicative of an active Ras, Myc, and/or Src, but not E2F3, β -catenin, TNF- α , or TGF- β pathway. To our knowledge, this is the first comprehensive survey of cancer pathway activities in nine major tumor types and the most widely used NCI60 cell lines. The “gene expression pathway signatures” we have defined could facilitate the understanding of molecular mechanisms in cancer development and provide guidance to the selection of appropriate cell lines for cancer research and pharmaceutical compound screening.
Properties Of Interpolated Mapping System Identification With Regard To Linear Systems

Abstract In this paper, we present some analytical results regarding the performance of a recently introduced method of system identification based on Interpolated Mapping (IM). The results are restricted to linear systems even though the method is intended, and appears to work well, for non-linear systems. The algorithm assumes the presence of sampled values of system states, based on which a map is defined that takes initial conditions on a grid in the state space to their respective images. Using the map with time step T, maps with time steps T/2, T/4, …, are found; ultimately, when the time step has become small enough, difference quotients furnish good estimates of the derivatives of the states. A function fit to these derivatives furnishes the equations of motion of the system. The methodology of IM is used to approximate the images of states that are not on the primary grid. We show in this paper that the IM approximation is actually exact when the underlying system is linear. Moreover, we derive relations between the dynamics of the underlying system and those of the iteration procedures used in the new identification algorithm. This development is used to verify the convergence characteristics of the method, and to select proper values for the parameters that appear in the iterative corrections.
Breakers on the Stalin Wave

Murphy, David E. What Stalin Knew: The Enigma of Barbarossa. Pleshakov, Constantine. Stalin's Folly: The Tragic First Ten Days of World War II on the Eastern Front.
Promoting ecoliteracy in an introductory database systems course: activities for the first week

Promoting sustainability, critical thinking, and ethical awareness are goals that appear in the vision statements of the majority of universities in the United States nowadays. One way of achieving these goals is by increasing the ecological literacy (i.e., ecoliteracy) of our students. In order to be effective, ecoliteracy should be taught not only in environmental studies classes, but rather across the institutional curriculum. In this paper we present three activities designed to be used in the first week of class in an introductory Database Systems course. Our activities promote critical thinking, systemic thinking, ethical behavior, and an increased awareness of ecological problems -- building blocks that set up the stage for teaching ecoliteracy.
Effect of Product Conductivity on Field‐Activated Combustion Synthesis

Experimental and modeling results on the field-activated combustion synthesis (FACS) of Nb5Si3 are reported. In the absence of an electric field and without reactant preheating, Nb5Si3 cannot be prepared by self-propagating high-temperature synthesis (SHS). Under the influence of a field a self-sustaining combustion wave is established whose rate of propagation decreases with traveled distance. For relatively low field values, the wave propagation mode changes from a continuous (smooth) to a spin mode. The product of synthesis depends on the mode of propagation. Synthesis during continuous wave propagation results in the formation of Nb5Si3, primarily in the α-modification. In contrast, when the wave propagates in a spin mode, the product is NbSi2 with unreacted niobium. The present observations demonstrate a case where the field effect is not localized, as was the case in previous studies. The difference in behavior is attributed to differences in the electrical conductivities of the product phases.
Modified method for combined DNA and RNA isolation from peanut and other oil seeds

Isolation of good quality RNA and DNA from seeds is difficult due to high levels of polysaccharides, polyphenols, and lipids that can degrade or co-precipitate with nucleic acids. Standard RNA extraction methods utilizing guanidinium-phenol-chloroform extraction has not shown to be successful. RNA isolation from plant seeds is a prerequisite for many seed specific gene expression studies and DNA is necessary in marker-assisted selection and other genetic studies. We describe a modified method to isolate both RNA and DNA from the same seed tissue and have been successful with several oil seeds including peanut, soybean, sunflower, canola, and oil radish. An additional LiCl precipitation step was added to isolate both RNA and DNA from the same seed tissues. High quality nucleic acids were observed based on A(260)/A(280) and A(260)/A(230) ratios above 2.0 and distinct bands on gel-electrophoresis. RNA was shown to be suitable for reverse transcriptase polymerase chain reaction based on actin or 60S ribosomal primer amplification and DNA was shown to have a single band on gel-electrophoresis analysis. This result shows that RNA and DNA isolated using this method can be appropriate for molecular studies in peanut and other oil containing seeds.
A new system for paper chromatography of polar steroids.

Abstract The new paper chromatographic system, isopropyl ether-ethylene glycol system, provides an improved and faster separation of steroids, particularly estrogens in paper chromatograms. The mobilities of a number of steroids are listed.
A new adaptive backstepping control algorithm for motion control systems ? an implicit and symbolic computation approach

A new adaptive integral backstepping control algorithm for motion control systems is proposed. The design approach is non-conventional in that it only implicitly incorporates error states into a design Lyapunov function and computes time derivative of the Lyapunov function symbolically to the point of getting parameter estimate update laws on which desirable structures are imposed. The closed-loop error system turns out to be linear and time-varying and can be reformulated as a linear–non-linear cascade system. Uniform exponential stability or absolute stability can be achieved. The design is robust against system parameter variations. The effectiveness and robustness of the control algorithm are verified by numerical examples. Copyright © 2002 John Wiley & Sons, Ltd.
Fourier Transform Raman spectroscopy with polarization modulation

Abstract Fourier Transform Raman spectroscopy can be performed with either a Martin—Puplett interferometer (MPI) or a Michelson interferometer (MI). With linearly polarized exciting light, the MPI provides information on the Stokes parameters S 1 , and S 3 of the scattered Raman light, from a single measurement. The parameter S 1 represents the difference in the scattered intensities with parallel and perpendicular polarizations while S 3 represents the difference in the scattered intensities with right and left circular polarizations. A procedure to extract these parameters with a Michelson interferometer is developed in this paper. A comparison of both approaches indicates that the use of the MPI is favored if the objective is to extract the Stokes parameters. Both approaches are equally favored if the objective is to measure the depolarization ratios. For measuring total Raman scattering, the use of a Michelson interferometer appears preferable.
Extrachromosomal amplification of the epidermal growth factor receptor gene in a human colon carcinoma cell line

In situ hybridization, using a biotinylated cDNA probe for the epidermal growth factor receptor (EGFR) gene, indicates that the amplified EGFR genes in the colon tumor cell line, DiFi, are localized in many small double minute chromosomes (dmin) of varying size and visibility. Analysis of the electrophoretic mobility of gamma-irradiated DNA from DiFi by pulsed-field gel electrophoresis and Southern blot hybridization using EGFR probe, indicates that the amplified EGFR in DiFi exists in extrachromosomal, covalently closed circular episomes, presumably equivalent to dmin. Two major and one minor species were observed which had estimated sizes of 650, 1,300, and 2,000 kb, respectively. The DiFi cell line appears to represent a unique case of extrachromosomal EGFR gene amplification in human cells.
Volume magnetostruction in EuO and MnF2

Abstract Measurements of the volume magnetostriction in EuO and MnF2 confirm predictions of a model based on the volume dependence of the dominant exchange constant. No adjustable parameters are used.
Flow between two stretchable disks—An exact solution of the Navier–Stokes equations ☆

Abstract In this work, an exact solution for the steady state Navier–Stokes equations in cylindrical coordinates is presented by similarity transformation technique. The solution involves the flow between two stretchable infinite disks with accelerated stretching velocity. The similarity equation was solved numerically and the effects of disk stretching parameter and stretching Reynolds number were studied. With the increase of the stretching Reynolds numbers, the fluid begins with a creeping type flow at R = 0 to a typical boundary layer type flow for large Reynolds numbers. The pressure parameter β changes from a positive number to a negative value with the increase of non-zero stretching parameter. The upper wall stretching parameter also greatly affects the velocity distribution between the two disks with a downward net flow for γ ≠ 1. The results are also useful as a benchmark problem for the validation of three-dimensional numerical computation code.
Use of microfluidic technology to analyze gene expression during Staphylococcus aureus biofilm formation reveals distinct physiological niches.

ABSTRACT The Staphylococcus aureus cid and lrg operons play significant roles in the control of autolysis and accumulation of extracellular genomic DNA (eDNA) during biofilm development. Although the molecular mechanisms mediating this control are only beginning to be revealed, it is clear that cell death must be limited to a subfraction of the biofilm population. In the present study, we tested the hypothesis that cid and lrg expression varies during biofilm development as a function of changes in the availability of oxygen. To examine cid and lrg promoter activity during biofilm development, fluorescent reporter fusion strains were constructed and grown in a BioFlux microfluidic system, generating time-lapse epifluorescence images of biofilm formation, which allows the spatial and temporal localization of gene expression. Consistent with cid induction under hypoxic conditions, the cid::gfp fusion strain expressed green fluorescent protein predominantly within the interior of the tower structures, similar to the pattern of expression observed with a strain carrying a gfp fusion to the hypoxia-induced promoter controlling the expression of the lactose dehydrogenase gene. The lrg promoter was also expressed within towers but appeared more diffuse throughout the tower structures, indicating that it was oxygen independent. Unexpectedly, the results also demonstrated the existence of tower structures with different expression phenotypes and physical characteristics, suggesting that these towers exhibit different metabolic activities. Overall, the findings presented here support a model in which oxygen is important in the spatial and temporal control of cid expression within a biofilm and that tower structures formed during biofilm development exhibit metabolically distinct niches.
Disproportionate epicardial dilation after transmural infarction of the canine left ventricle: Acute and chronic differences

Abstract The relation between acute disproportionate infarct dilation and late postinfarct left ventricular remodeling was examined by implanting multiple radiopaque epicardial markers in the left ventricle of eight dogs and determining regional surface deformation after acute and chronic transmural infarction. Transmural injury was produced by combining coronary ligation with distal embolization of a rubber polymer. Dogs were anesthetized and studied before and 1 h, 24 h and 1 week after infarction. Marker positions were recorded by rapid biplane cineradiography, and three-dimensional coordinates were reconstructed by a computer-assisted tracking system. Regional deformation was expressed by a local surface area equal to the sum of multiple (three to four) triangles generated by marker triplets. As early as 1 h after infarction, end-diastolic area in the infarct region increased by 20.3 ± 3.1%, while that in the remote region increased by only 7.9 ± 3.5%. Both changes and the difference between them were significant. At 24 h after infarction, both territories continued to undergo dilation, this time to a similar extent (additional +10.3% in the remote region and +10.1% in the infarct region), thus maintaining the significant disproportionate infarct dilation. At 1 week, however, the infarct territory remained dilated with a mean end-diastolic area 31.4 ± 3.1% above control, while that in the remote region returned to a net mean 8.5 ± 4.7% increase. Thus, the major extent of disproportionate infarct dilation occurs within 1 h after transmural injury and is accompanied by remote dilation as a compensatory response. The extent of further infarct dilation achieved by 24 h is maintained in the chronic infarct, and compensatory mechanisms enable noninjured myocardium to become less dilated. This is an even earlier time course than previously demonstrated, which suggests that attempts to limit infarct dilation should target the acute phase of injury.
Pidgin English in Nauru

This article reports on a preliminary study of an English-lexifier Pidgin spoken on the tiny Pacific island of Nauru. This pidgin has distinctive features of both Chinese Pidgin English and Pacific Pidgin English, as well as many unique characteristics. Socio-historical information shows that these two forms of Pidgin English have come into contact in Nauru and the data suggests that pidgin mixing, a form of koineization, has occurred. The linguistic consequences of such a mixture are similar to those of the mixing of other linguistic subsystems such as regional dialects. The data also supports observations about the problems of genetic classification and the significance of mixing in tracing the development of pidgins in the Pacific and other areas.
Slow axonal protein transport and axoplasmic organization.

Abstract A recently formulated structural theory of axonal transport suggests that each group of transported material is a distinct class of functionally related structures and that the proteins making up those structures, with few exceptions, are found in only one rate component, thus maintaining a close noncovalent association during transport. If such a relationship exists, one would postulate that the labelled proteins at the leading edge and trailing edge of a rate component following a pulse of radioactive amino acid would be present in similar proportions. After retinal ganglion cell proteins were labelled by intraocular injection of radioactive amino acid in the guinea pig eye, the optic nerve and tract were analyzed at several post-injection intervals. The data thus derived support the existence of a close relationship among the “soluble” proteins of slow component b and are consistent with the structural concept of axonal transport. If diffusion were the mechanism of transport, the larger proteins would be expected to move slower than the smaller proteins. Such insights into the process of axonal transport should help to identify the variables critical to survival of neurons following acute trauma and degenerative diseases.
The election of 1994 in El Salvador

After voting in two rounds of elections in the Spring of 1994, El Salvadorans elected a president, a vice-president (on the same ticket), 84 legislative deputies and 262 municipal boards. Armando Calderon Sol (a former Mayor of San Salvador) of the rightist ARENA (National Republican Alliance) received 49.03 per cent of the vote on 20 March; having narrowly missed obtaining the required absolute majority of the popular vote (50 per cent plus one), he was forced into a run-off election on 24 April. In this election, Calderon Sol defeated his only rival, Ruben Zamora of the leftist FMLN/CD/MNR (Farbundo Marti Liberation Front/Democratic Convergence/National Revolutionary Movement) coalition by attracting the support of 68.35 per cent of the voters. ARENA won 39 of the seats in the legislature; by forming an alliance with the conservative PCN (Party of National Conciliation), it created a majority of 43 deputies to cement its control of this branch of government.
Real-Time Imaging of Clathrin Dynamics in Three Dimensions

Clathrin mediated endocytosis is a crucial factor in maintaining cellular dynamics. So far, real-time observation of this phenomenon has been achieved using methods that are limited to two dimensional spatial analysis even though cells have three dimensional geometries. Here we have used a fast, confocal based, three dimensional automated tracking scheme to analyze clathrin coat dynamics at the ventral and dorsal surfaces of mammalian cells. This technique presents a direct observation of a clathrin mediated virus entry at the apical surface of polarized cells for the first time. Our analysis has shown that a sub-population of clathrin-coated structures ascend from plasma membrane for hundreds of nanometers before they uncoat. Elevation of these structures depends on actin machinery and is enhanced by increasing membrane tension. On the migrating cells, we have found that clathrin-mediated endocytosis is constrained to the dorsal side of the plasma membrane at the sites of protrusion. Clathrin-coats emanating at the leading edge move towards the center of the cell with velocities inversely proportional to the migration speed of the cell.
Large area detectors and new sensor technologies at Fairchild Imaging

In this paper, we present an overview of large area detector arrays and new sensor technologies currently under development at Fairchild Imaging. We discuss on-going development efforts aimed at satisfying the increasing need for large format, scientific grade detectors, and review significant progress in achieving higher spatial resolution in large area back-illuminated CCDs. We also present the performance characteristics of a new prototype CCD/CMOS hybrid sensor designed for low light level imaging and capable of high speed, low power, and very low noise.
The Effect of Pressure on the Electrical Resistance of Copper at Low Temperatures

The resistivity of copper under hydrostatic pressures up to 3000 atm has been measured at temperatures between 4° K and room temperature. Two specimens of commercially pure copper (99⋅98%) and an alloy of 0⋅056 at. % iron in copper were studied, the alloy being chosen because it showed a large resistance minimum. The effect of pressure on the ideal resistivity is in good agreement with Gruneisen’s theory. There were some theoretical reasons for expecting that the alloy would have a large pressure coefficient of resistivity at or below the temperature of the resistance minimum. The pressure coefficient at these temperatures was, however, quite small and similar in value to the pressure coefficients of residual resistivity of the two purer specimens. Both the residual resistivity of the alloy and its pressure coefficient appeared to be strongly dependent on temperature.
Exploring the motivation to create social ventures: a model of moral engagement

This paper develops a model of moral engagement to explain the motivation underlying the creation of social ventures. The fundamental premise of the model is that moral engagement is an important determinant of people’s intention to start social ventures. The paper concludes with a discussion of the research implications of the model of moral engagement.
Letters of Recommendation in Academe: Do Women and Men Write in Different Languages?.

The present study analyzes seventy-eight letters of recommendation sent to a department of sociology and anthropology for six replacement and two tenure-track positions. The sample consists of fifteen pairs of letters written for women and twenty-four pairs written for men. Each pair of letters includes one written by a woman and one written by a man for the same candidate. Men and women wrote letters differently, but their letters also varied by the gender of the applicant. The concept of tokenism, Gilligan’s theory about moral reasoning, and Acker’s discussion of gendered organizations are used to interpret these differences.
Torsional rigidity of DNA and length dependence of the free energy of DNA supercoiling.

Abstract By analyzing the Boltzmann populations of DNA topoisomers that differ only in their linking numbers, the dependence of the free energy ΔGτ of DNA supercoiling on the linking number α has been determined for DNA rings as small as 200 base-pairs (bp) in length. All experimental data can be fitted by the relation ΔGτ = K(α-α∘)2, where α∘ is a constant for a given DNA at a given set of conditions and K is a DNA length-dependent proportionality constant. For DNA rings with length N larger than 2000 bp, K is inversely proportional to N and the product N K is nearly a constant around 1150 RT · bp. For rings smaller than 2000 bp N K increases steadily with decreasing N; for a 200 bp ring N K is 3900 RT · bp. The increase in N K when N decreases can be interpreted as a result of the decrease in the contribution of the fluctuation in the writhing number to the equilibrium distribution in α. Assuming that the writhing contribution approaches zero for DNA rings 200 bp in size, the torsional rigidity of the DNA double helix is calculated to be 2.9 × 10−19 erg cm. In addition, the large value of K for the small circles allows precise calculation of the helical repeat of DNA. For the 210 bp rings, the repeat is measured to be 10.54 bp.
Resorption of calcified cartilage as seen in Meckel's cartilage of rats

In rats, a portion of Meckel's cartilage — that lying within the mandible but proximal to the rostral convergence of the bars — gives rise to no definitive structures. It offers especially favorable opportunity to study cartilage resorption. By the eighteenth fetal day it is established as a hyaline cartilage bar, and a thin perichondral bone shell starts to form on its lateral aspect, completing encirclement in the next two days. On day 19 cartilage within this bone shows chondrocyte hypertrophy, lacunar enlargement, and matrix calcification. Osteoclasts open a fenestra laterally in the bone and commence removal of calcified cartilage matrix. The erosion front expands rapidly, moving medially (preceded by cartilage hypertrophy and calcification) and extending proximally and distally along the segment. Chondroclasts (multinucleated cells identical with osteoclasts) dominate the erosion front. Capillaries and various mononucleated cells follow. Bone formation is much delayed except in the most rostral extremity, so that, contrary to the situation in endochondral osteogenesis, one is examining calcified cartilage resorption in uncomplicated form. This resorption, including the perichondral bone shell, is virtually complete by day 21, and intramembranous bony reorganization of the site is in progress at birth. Several features of chondroclasts, including some in dispute or not easily seen in vivo, are well displayed. These include ameboid form with pseudopodial extensions (sometimes filamentous), and fusion of some released chondrocytes with entering chondroclasts. Osteo/chondroclasts are often found in contact with perichondral bone at one extremity and calcified cartilage elsewhere on the same cell. There is evidence that matrix calcification is prerequisite to the chondroclastic activity.
Transient simulation of a capacity-modulated, direct-expansion, solar-assisted heat pump

Abstract The long-term thermal performance of a direct-expansion, solar-assisted heat pump is determined from the transient simulation of the system. The system employs a bare collector that also acts as the heat pump evaporator. Of particular interest in this study is the configuration in which the compressor and the collector area are properly matched from the long-term thermal performance point of view. This matching is achieved through multistep as well as two-step compressor capacity modulation. In addition to examining the effects of compressor capacity modulation, the effects of various system parameters such as collector area, storage volume, load temperature, wind speed, collector slope, and refrigerant properties are also studied in detail. Monthly averaged thermal performance parameters such as the heat pump system coefficient of performance are determined by executing a computer simulation program that uses the typical meterological year (TMY) solar data for Norfolk, Virginia. Results indicate that the system performance is governed strongly by collector area, compressor RPM, load temperature, and refrigerant properties. The remaining parameters have only weak influence on the long-term system performance of direct expansion solar-assisted heat pump (SAHP) system considered in this study.
Pharmacist-managed tobacco cessation program in Veterans Health Administration community-based outpatient clinic.

ABSTRACT Objective To describe an ongoing pharmacist-managed tobacco cessation clinic and assess the long-term effectiveness of the program. Setting Veterans Health Administration (VHA) community-based outpatient clinic in Missoula, Montana. Participants Pharmacy professor/clinical pharmacy specialist, advanced pharmacy practice experience students, and tobacco cessation participants. Practice Description Ongoing, pharmacist-managed tobacco cessation program offered to veterans. Practice Innovation With use of the “Vets without Cigarettes” program developed by the Montana VHA and the most current strategies reported in the literature, the clinical pharmacy specialist and pharmacy students provide tobacco cessation services for Missoula Veterans Affairs Primary Care Center veterans. Activities include a three-session program using the Transtheoretical Model of Change, tobacco cessation pharmacotherapy, behavioral strategies, cognitive techniques, documentation, and follow-up survey. Main Outcome Measure Percentage of veterans contacted reporting tobacco abstinence. Results Follow-up survey results were obtained for 130 (87.8%) of 148 veterans attending one or more sessions of the tobacco cessation class between November 1999 and December 2003. Of the 130 veterans contacted, 54 (41.5%) continued to be tobacco free. Conclusion This program demonstrates that pharmacists are effective providers of tobacco cessation services. Furthermore, a comprehensive tobacco cessation program is provided that can serve as a model to guide pharmacists in assisting more patients to become tobacco free and live healthier lifestyles.
Release of endogenous serotonin and histamine from murine mastocytoma cells by various exogenous amines

Abstract Studies have been conducted on 3 clonal sublines of mastocytoma cells, maintained continuously in cell culture: X-2, with low levels of serotonin (5-HT) and histamine (H); X-163, with high levels of 5-HT and moderate levels of H; and HC, with high levels of both 5-HT and H. The purpose of these experiments was to determine the specificity of various amines in causing the release of 5-HT and H from these cells. Both of the endogenous amines were released when the cells were incubated in the presence of the following amines: tyramine, tryptamine, 4-chloroamphetamine and amphetamine. In addition 5-HT caused the release of H and vice versa, independent of inhibition of cell growth. Notable among amines incapable of causing any significant release were putrescine, spermine and spermidine. Experiments on cells made to contain isotopically labeled 5-HT and H indicated that the storage sites of the endogenous amines may be identical.
The Role of Spatial Reference Frames in Architecture Misalignment Impairs Way-Finding Performance

It is generally recognized that the spatial structure of a building is an important factor in way-finding performance. However, surprisingly little research has related way-finding performance directly to topological and geometrical properties of spatial environments. In this study, the authors provide empirical evidence that way-finding performance and the ability of people to orient themselves in their environment depends partly on geometrical relations between different parts of the space. The authors propose that the misalignment of local, cognitive reference frames suggested by architectural features leads to way-finding problems and impairs the integration of spatial knowledge. In an experiment with 56 participants, the authors tested way-finding performance and spatial memory for four virtual environments. Environments differed systematically in their alignment of parts of the building. Results show a main effect of alignment for both way-finding and pointing measures. Implications of these finding...