cssi/SciSciGPT-SciSciNet huggingface dataset:
Fracture and progressive failure of defective graphene sheets and carbon nanotubes

Abstract An atomistic based finite bond element model for the prediction of fracture and progressive failure of graphene sheets and carbon nanotubes is developed by incorporating the modified Morse potential. The element formulation includes eight degrees of freedom reducing computational cost compared to the 12 degrees of freedom used in other FE type models. The coefficients of the elements are determined based on the analytical molecular structural mechanics model developed by the authors. The model is capable of predicting the mechanical properties (Young’s moduli, Poisson’s ratios and force–strain relationships) of both defect-free and defective carbon nanotubes under different loading conditions. In particular our approach is shown to more accurately predict Poisson’s ratio. The numerical prediction of nonlinear stress–strain relationships for defect-free nanotubes including ultimate strength and strain to failure of nanotubes is identical to our analytical molecular structural mechanics solution. An interaction based mechanics approach is introduced to model the formation of Stone–Wales (5-7-7-5) topological defect. The predicted formation energy is compared with ab initio calculations. The progressive failure of defective graphene sheets and nanotubes containing a 5-7-7-5 defect is studied, and the degradation of Young’s moduli, ultimate strength and failure strains of defective nanotubes is predicted.
MRI-guided access to the retropharynx.

Purpose To describe MR-guided access to the retropharynx for precise fine-needle aspiration cytology (FNAC), and other indications for needle placement. Materials and Methods A retrospective review was made of 15 procedures that had been performed on 14 patients. These patients had a retropharyngeal mass on MRI and had undergone MR-guided minimally invasive access to the retropharynx for either diagnostic or therapeutic intervention in the period of October 1989 to January 2000. Results All 14 patients underwent MR-guided access to the retropharynx for FNAC without immediate or delayed complications. MRI confirmed that the biopsy needle was within the retropharyngeal mass in all patients. MR-guided FNAC revealed five true-positive, five true-negative, four indeterminate, and no false-positive cases. Ten of the 14 patients (71%) had diagnostic aspirations. In one patient with retropharyngeal extension of carcinoma, an MR-guided approach was used for the experimental interstitial laser therapy (ILT). Conclusion The results suggest that an MR-guided retromandibular approach to biopsy of retropharyngeal mass is minimally invasive and safe. J. Magn. Reson. Imaging 2003;17:317–322. © 2003 Wiley-Liss, Inc.
A Three-Wave Longitudinal Analysis of Preexisting Beliefs, Exposure to Pornography, and Attitude Change

Much of the research on pornography and sexually permissive attitudes has been cross-sectional, has assessed only straightforward exposure–attitude correlations, has focused on adolescents, or has been conducted outside of the United States. This study employed nationally representative, longitudinal data gathered from adults in the United States to redress these gaps in the literature. After controlling for earlier sexual permissiveness and a number of other potential confounds, a positive prospective association between pornography exposure and subsequent sexual permissiveness was found. Furthermore, in alignment with the 3AM model of media sexual socialization, this association was moderated by participants’ preexisting liberal–conservative ideology.
Double resonance 1-D photonic crystal cavities for single-molecule mid-infrared photothermal spectroscopy

We propose a mid-infrared spectroscopic technique capable of detecting a single small molecule without using cryogenically cooled detectors. Such record sensitivity is attained by leveraging dramatically amplified photothermal effects in a pump-probe doubly resonant cavity.
Identification and subcellular localization of catalase activity in bovine adrenal medulla and cortex.

Abstract Catalase activity was detected in homogenates of bovine adrenal cortex and medulla. Analysis by equilibrium density centrifugation in isoosmotic metrizamide-sucrose gradients revealed that 70% of the medullary catalase activity was soluble while most of the remainder was found in a particulate form with a density of 1.175 g/ml. This was distinct from the densities of lysosomes, mitochondria, and chromaffin granules. Catalase activity in adrenal cortex was primarily (90%) soluble with only 6% being particulate, with a density of 1.185 g/ml. d -Amino acid, uric acid, and α-hydroxyacid oxidase activities, often associated with peroxisomes in other tissues, were absent from homogenates and catalase-containing gradient fractions from either cortex or medulla. There was an indication that some catalase activity was associated with chromaffin granules on the basis of density gradient analysis of both medullary homogenates and crude granule preparations. When granule fractions were subjected to osmotic shock, catalase activity distributed between soluble and sedimentable fractions differently from epinephrine and dopamine β-hydroxylase activity. The sedimentable catalase activity remained associated with chromaffin granule membranes upon isopycnic centrifugation. We concluded that catalase activity in both adrenal cortex and medulla was largely cytoplasmic, but that both tissues contained at least some catalase in dense organelles. Catalase activity which may be associated with chromaffin granules represents a small fraction of the total activity in the medulla.
MiCA: A web-based tool for the analysis of microbial communities based on terminal-restriction fragment length polymorphisms of 16S and 18S rRNA genes

A web-based resource, Microbial Community Analysis (MiCA), has been developed to facilitate studies on microbial community ecology that use analyses of terminal-restriction fragment length polymorphisms (T-RFLP) of 16S and 18S rRNA genes. MiCA provides an intuitive web interface to access two specialized programs and a specially formatted database of 16S ribosomal RNA sequences. The first program performs virtual polymerase chain reaction (PCR) amplification of rRNA genes and restriction of the amplicons using primer sequences and restriction enzymes chosen by the user. This program, in silico PCR and Restriction (ISPaR), uses a binary encoding of DNA sequences to rapidly scan large numbers of sequences in databases searching for primer annealing and restriction sites while permitting the user to specify the number of mismatches in primer sequences. ISPaR supports multiple digests with up to three enzymes. The number of base pairs between the 5′ and 3′ primers and the proximal restriction sites can be reported, printed, or exported in various formats. The second program, APLAUS, infers a plausible community structure(s) based on T-RFLP data supplied by a user. APLAUS estimates the relative abundances of populations and reports a listing of phylotypes that are consistent with the empirical data. MiCA is accessible at http://mica.ibest.uidaho.edu/.
Effects of hydrocarbon quenching in gas chromatography when using the flame photometric detector

The long time retardation of the main hydrocarbon peak in the chimney of the flame photometric detector greatly reduces the responses of later-eluting sulfur compounds. In the absence of hydrocarbons in the flame, the slope (s) of the log I vs. log [S] plot (where I is the sulfur response and [S] is the sulfur concentration in the sample) is of the highest value and is constant for all experimental conditions tested. Flame hydrocarbons cause the s value to decrease, and this is dependent on the oxygen to hydrogen ratio in the flame (O/H) and, under certain conditions, also on the sulfur to carbon ratio (S/C) of the sample. The abnormalities observed in the determination of methyl thiol in natural gas are explained on the basis of the present study.
Lipoprotein-Associated Phospholipase A2, High-Sensitivity C-Reactive Protein, and Risk for Incident Ischemic Stroke in Middle-aged Men and Women in the Atherosclerosis Risk in Communities (ARIC) Study

Background Measurement of inflammatory markers has been reported to identify individuals at increased risk for ischemic stroke. Lipoprotein-associated phospholipase A 2 (Lp-PLA 2 ) is a proinflammatory enzyme secreted by macrophages. We assessed Lp-PLA 2 and C-reactive protein (CRP) levels along with traditional risk factors to examine their relation to ischemic stroke. Methods A proportional hazards model was used in a prospective case-cohort study of 12 762 apparently healthy middle-aged men and women in the Atherosclerosis Risk in Communities (ARIC) study who were observed for about 6 years. Results Mean Lp-PLA 2 and CRP levels adjusted for sex, race, and age were higher in the 194 stroke cases than the 766 noncases, whereas low-density lipoprotein cholesterol (LDL-C) level was not significantly different. Both Lp-PLA 2 and CRP levels were associated with ischemic stroke after adjustment for age, sex, and race: hazard ratios were 2.23 for the highest vs the lowest tertile of Lp-PLA 2 and 2.70 for CRP level higher than 3 vs lower than 1 mg/L. In a model that included smoking, systolic hypertension, lipid levels, and diabetes, Lp-PLA 2 and CRP levels in the highest category were associated with hazard ratios of 1.91 (95% confidence interval, 1.15-3.18; P = .01) and 1.87 (95% confidence interval, 1.13-3.10; P = .02), respectively. Individuals with high levels of both CRP and Lp-PLA 2 were at the highest risk after adjusting for traditional risk factors compared with individuals with low levels of both, whereas others were at intermediate risk. Conclusion Levels of Lp-PLA 2 and CRP may be complementary beyond traditional risk factors in identifying middle-aged individuals at increased risk for ischemic stroke.
Bicuspid Aortic Valve Comparison of Congenital and Acquired Types

Two dominant types of congenital bicuspid valves are described. The classical type is characterized by the presence of a low ridge or raphe along the aortic aspect of the conjoined cusp. The other is characterized by a tall raphe, the upper edge of which corresponds with the upper level of the aortic cusps. Some such ridges may result from acquired fusion of the adjacent halves of two cusps (yielding an acquired bicuspid valve). In other cases, the ridge is a protrusion of the aorta and not derived from fused cuspid tissue. Such valves are considered to portray a condition which may be termed pseudoacquired congenital bicuspid aortic valve. The acquired bicuspid valve in some cases is compounded of this congenital process and acquired fusion of cuspid tissue. The ratio of classical congenital bicuspid to pseudoacquired congenital bicuspid aortic valve is 4 to 1. Exceptional forms of pseudoacquired congenital bicuspid aortic valves are also described.
In vivo monoamine oxidase inhibition by d-amphetamine.

Abstract In vitro, d- and l-amphetamine (AMPH) are reversible monoamine oxidase (MAO) type A inhibitors, the d-form being approximately five times more potent. Experiments were conducted in rats to determine whether MAO inhibition occurs in vivo. d-AMPH was more effective than l-AMPH at decreasing striatal 3,4-dihydroxyphenylacetic acid (DOPAC). However, assays of striatal MAO activity following administration of AMPH in vivo failed to show MAO inhibition. In other experiments, rats were treated with d-AMPH (zero time) followed by phcnelzine (1 hr), an irreversible MAO inhibitor, and were killed at 25 hr. MAO activity was determined in vitro for the striatum and the rest of the brain using serotonin (MAO-A) and phenylethylaminc (MAO-B) as substrates. d-AMPH provided significant protection against MAO-A inhibition by phenelzine, whereas l-AMPH and cocaine (used instead of AMPH) were without effect. d-AMPH failed to protect against MAO-B inhibition by phenelzine. Thus, d-AMPH appears to inhibit reversibly MAO type A in vivo. However, using the same ‘protection protocol’, d-AMPH failed to oppose phenelzine-induced lowering of striatal DOPAC. Experiments were undertaken to determine whether the protective effect of d-AMPH on MAO type A would influence striatal dopamine depletion by RO4-1284, a rapidly acting reserpine-like agent. RO4-1284-induced depletion of dopamine was inhibited by phenelzine. Prior treatment with d-AMPH reduced significantly the protective effect of phenelzine, suggesting reversible, intraneuronal MAO inhibition by d-AMPH in vivo. The possible neuronal mechanisms for these events are discussed.
Patterns of Ethylene and Carbon Dioxide Evolution during Cotton Explant Abscission.

The relationship between abscission and the evolution of ethylene and CO(2) was examined in explants and explant segments of cotton seedlings (Gossypium hirsutum L. cv. Acala SJ-1) under both static and flow system conditions, and in the presence and absence of mercuric perchlorate. Explant excision was immediately followed by increased ethylene evolution (wound ethylene); senescence was also accompanied by increased ethylene evolution (senescence ethylene). One or two ethylene peaks were found to interrupt the low background rate of ethylene evolution during the period between excision and senescence. The first intermediate ethylene peak coincided with a rise in CO(2) evolution; however, precedence could not be established. No statistical correlations were discovered between either intermediate ethylene peak and abscission. The best statistical correlation was found between wound ethylene and abscission at 12 hr after excision. No positive correlations were found between senescence ethylene and abscission. Implications of these results for the understanding of the role of ethylene in explant abscission are discussed.Relationships between a number of different explant treatments and ethylene evolution were also examined. Ethylene production in response to indoleacetic acid applications, abscisic acid applications, and different types of wounding is summarized. It was concluded that the results of the standard abscission bioassay (conducted in Petri dishes) have not been influenced by unnatural ethylene accumulations.
Association of Ebola-related Reston virus particles and antigen with tissue lesions of monkeys imported to the United States

Abstract During 1989–1990, an epizootic involving a filovirus closely related to Ebola virus occurred in a Reston, Virginia, primate-holding facility. Tissues were collected from cynomolgus monkeys and examined by electron microscopy and immunohistochemistry for Ebola-related viral antigen. Viral replication was extensive in fixed tissue macrophages, interstitial fibroblasts of many organs, circulating macrophages and monocytes, and was observed less frequently in vascular endothelial cells, hepatocytes, adrenal cortical cells and renal tubular epithelium. Viral replication was observed infrequently in epithelial cells lining ducts or mucous membranes, intestinal epithelial cells, eosinophils and plasma cells. Replication of Reston virus in lymphocytes was never observed, in contrast to reports of lymphocytes of monkeys experimentally infected with the Ebola-Zaire virus. Free filoviral particles were seen in pulmonary alveoli and renal tubular lumina, which correlates with epidemiological evidence of droplet and fomite transmission. Viral infection of interstitial fibroblasts and macrophages caused multisystemic disruptive lesions involving connective tissue. Focal necrosis in organs where viral replication was minimal may have been secondary to ischaemia caused by fibrin deposition and occasional platelet-fibrin thrombi. Immunoelectron microscopy on sections of liver, differentiated viral tubular inclusion masses and precursor material from non-viral tubuloreticular inclusions. Immunohistochemistry showed that the distribution of viral antigen in affected tissue correlated well with ultrastructural localization of virions.
Energy spectral characteristics of auroral electron microburst precipitation

We consider data from a rocket experiment designed to study auroral microburst precipitation. Our rocket instruments had high energy spectral resolution which allowed us to characterize the electron energy spectra. Data from the field aligned electron detector show that the majority of the spectra fit an exponential form in the 45–70 keV energy range. Approximately 15% of the spectra fit a power law form for high energies (70–150 keV' and 45% fit an additional exponential form for low energies (20–45 keV'. The multi-component spectra appeared during both microburst and non-burst times. The e-folding energies for the 45–70 keV energy range increased as the flux increased. Some of these features can be explained by a cyclotron wave-particle interaction mechanism. We also observed a weak peak in the energy spectrum at about 45 keV, suggesting the existence of field-aligned potential drops associated with microburst production.
Case management for heart failure in the emergency department

Heart failure affects approximately 5 million individuals in the United States and is the most common discharge diagnosis among the elderly. The number of individuals diagnosed with heart failure will continue to rise as the population of the United States ages. The natural course of the disease is characterized by periods of stability interrupted by periods of symptom exacerbation. These periods of exacerbation often require emergency intervention or hospitalization for management. Once an individual is hospitalized, they are at a greater risk for rehospitalization. The causes of rehospitalizations are multifactorial and many are preventable. Case managers are in a position to have a positive impact on the readmission rate. Interventions include adherence to medication guidelines, increasing patients' knowledge of self-care measures, assessing discharge readiness and needs, and increasing the frequency of symptom monitoring for early intervention. Case management begins in the emergency department and facilitates care throughout the patient's stay by fostering communication among all caregivers and the patient and family. Case managers also affect the quality of care patients receive by instituting processes that streamline care and ensure that quality care is provided to the patients. They also serve as mentors and resources for other members of the healthcare team. Most of the information about case management comes from inpatient and outpatient programs; however, the emergency department nurse can adapt these models to support their role. More research is needed as to what specific portions of the case manager's role are most appropriate for the emergency department.
Brain responses to nouns, verbs and class-ambiguous words in context

Recent neuropsychological and imaging data have implicated different brain networks in the processing of different word classes, nouns being linked primarily to posterior, visual object-processing regions and verbs to frontal, motor-processing areas. However, as most of these studies have examined words in isolation, the consequences of such anatomically based representational differences, if any, for the processing of these items in sentences remains unclear. Additionally, in some languages many words (e.g. \`drink') are class-ambiguous, i.e. they can play either role depending on context, and it is not yet known how the brain stores and uses information associated with such lexical items in context. We examined these issues by recording event-related potentials (ERPs) in response to unambiguous nouns (e.g. \`beer'), unambiguous verbs (e.g. \`eat'), class-ambiguous words and pseudowords used as nouns or verbs within two types of minimally contrastive sentence contexts: noun-predicting (e.g. \`John wanted THE [target] but …') and verb-predicting (`John wanted TO [target] but …'). Our results indicate that the nature of neural processing for nouns and verbs is a function of both the type of stimulus and the role it is playing. Even when the context completely specifies their role, word class-ambiguous items differ from unambiguous ones over frontal regions by ~150 ms. Moreover, whereas pseudowords elicit larger N400s when used as verbs than when used as nouns, unambiguous nouns and ambiguous words used as nouns elicit more frontocentral negativity than unambiguous verbs and ambiguous words used as verbs, respectively. Additionally, unambiguous verbs elicit a left-lateralized, anterior positivity (~200 ms) not observed for any other stimulus type, though only when these items are used appropriately as verbs (i.e. in verb-predicting contexts). In summary, the pattern of neural activity observed in response to lexical items depends on their general probability of being a verb or a noun and on the particular role they are playing in any given sentence. This implicates more than a simple two-way distinction of the brain networks involved in their storage and processing. Experience, as well as context during on-line language processing, clearly shapes the neural representations of nouns and verbs, such that there is no single neural marker of word class. Our results further suggest that the presence and nature of the word class-based dissociations observed after brain damage are similarly likely to be a function of both the type of stimulus and the context in which it occurs, and thus must be assessed accordingly.
Partial molar volumes of ethyl acetate from supercritical CO2 desorption data

Abstract Previous experimental results for the desorption of ethyl acetate from activated carbon in supercritical carbon dioxide provided values of equilibrium adsorption coefficients as functions of temperature and pressure. The plot of equilibrium desorption coefficient (or the related chromatographic capacity factor) vs. density is linear on log-log coordinates. The equilibrium adsorption coefficients are herein used to determine the infinite-dilution partial molar volume of ethyl acetate in supercritical carbon dioxide as a function of density for different temperatures. The values of the partial molar volume tend to large negative values as the critical temperature for carbon dioxide is approached.
The effect of couple-stresses on the diffraction of plane elastic waves by cylindrical discontinuities

Abstract This investigation considers the effect of couple-stresses on dynamical stresses developed around a circular cylindrical discontinuity embedded in an infinite medium by the diffraction of steady plane parallel elastic compressional waves propagating in the medium. Both a cavity and a rigid cylinder with an immovable cylinder treated as a special case of the latter are considered. Numerical results valid at large wavelengths for a fixed Poisson's ratio showing variation of the modified stresses against different parameter ratios involved are presented in the form of curves and compared with their classical values obtained as a limiting case. In either case, at certain wavelengths, quite appreciable deviations from classical results occur. The effect of couple-stresses on the motion of a rigid cylinder is discussed.
Shape restriction of the multi-dimensional Bernstein prior for density functions

Random Bernstein polynomials induces a probability measure on the space of multivariate density functions on a unit cube. For density estimation, it is important that the Bernstein prior can be restricted to an admissible class of densities with certain geometric properties of the target density. In this article, we study the shape properties such as monotonicity, convexity, and symmetry of the Bernstein prior.
Effect of isoproterenol (ISO) on rat heart, liver, kidney, and muscle tissue levels of zinc, copper, and magnesium

X-ray fluorescence and atomic absorption spectrometry were used to measure the concentrations of zinc, copper, and magnesium in the heart, liver, skeletal muscle, and kidney following isoproterenol-induced myocardial necrosis in male albino rats. Serum activities of lactic dehydrogenase (LDH), creatine phosphokinase (CPK), and glutamic oxaloacetic transaminase (SGOT) were also measured. There was depletion of myocardial zinc, copper, and magnesium on d 1, followed by an uptake of all these elements on d 2. The liver showed a significant uptake of magnesium, along with depletion of copper. There was no change in the kidney and skeletal muscle concentrations of these elements. Possible explanations for the observed changes and their therapeutic significance are presented.
Invasion percolation through minimum-weight spanning trees

Invasion percolation is often used to simulate capillary-dominated drainage and imbibition in pore networks. More than a decade ago it was observed that the part of a pore network that is involved in an invasion bond percolation is a minimum-weight spanning tree of the network, where the weights indicate resistances associated with the bonds. Thus, one can determine a minimum-weight spanning tree first and then run the invasion bond percolation on the minimum-weight spanning tree. The time complexities of the two steps are O(malpha(m,n)) and O(n) , respectively, where m is the number of edges, n is the number of vertices, and alpha(,) denotes the inverse Ackermann function. In this paper we (1) formulate the property of minimum-weight spanning trees that justifies the two-step approach to invasion bond percolation, (2) extend the two-step approach to invasion site percolation, and (3) further extend it to simulations of drainage (imbibition) that include trapping of the wetting (nonwetting) phase. In case of imbibition we also take snap-off into account. As a consequence, all these simulations can now be done in O(malpha(m,n)) .
The Image of Observables

This paper challenges a central tenet of constructive empiricism, namely that empirical adequacy has a privileged epistemic status. I argue that perceptions of observables are theory-wrought, and theory-wrought in the same ways as the observation sentences we use to describe those perceptions. van Fraassen can draw no privileged or fundamental distinction between what we observe and interpreting those observations through theory. Since empirical adequacy depends upon accurately describing what we observe, and we have no theory-independent reason to believe that what we 'observe' is a reflection of what is true, then empirical adequacy can inherit no special connection to what is real via what we observe. The epistemological significance of empirical adequacy is thereby reduced.
Isolation and Characterization of a Soluble Branched Starch Fraction from Corn Masa Associated with Adhesiveness

ABSTRACT A water-soluble starch fraction isolated from corn masa and identified by HPSEC as predominantly fragmented amylopectin was highly correlated in amount to both masa adhesiveness (r = 0.890, P < 0.01) and cook time (r = 0.957, P < 0.01). The molecular weight of the component ranged from approximately 6.4 × 105 to 1.2 × 106, based on HPSEC column calibration with pullulan standards. Debranching with isoamylase illustrated that the structure of the soluble masa starch component was highly branched with a similar debranched profile to native amylopectin. Further analysis revealed that a minor amount of amylose was present in the second half of the broad HPSEC peak containing the fragmented amylopectin component. There was a high second-order correlation (r = 0.998, P < 0.01) between the absorbance at the wavelength of maximum absorbance (λmax) of the soluble fraction from masa (527–532 nm) and masa adhesiveness, indicating that a rapid assay for masa adhesiveness could easily be developed. Increasing...
Effect of Indomethacin on Increased Resistance to Bacterial Infection and on Febrile Responses Induced by Muramyl Dipeptide

The pyrogenicity in the rabbit and the ability to stimulate nonspecific resistance to bacterial infection in the mouse of muramyl dipeptide (MDP), a synthetic immunoadjuvant, are known to be enhanced when the glycopeptide has been conjugated to a carrier. The effects of indomethacin on fever induced by MDP or its conjugated derivative were studied. Indomethacin reduced febrile responses to MDP or its derivative, although it did not decrease production of endogenous pyrogen in vivo or in vitro. When incubated with rabbit peritoneal cells, indomethacin suppressed the elevation in prostaglandin levels usually induced by MDP. When administered to mice, indomethacin alone stimulated resistance to bacterial infection and, under appropriate conditions, had a strong synergistic effect when combined with free or conjugated MDP. The results demonstrate that neither pyrogenicity nor increased prostaglandin levels are prerequisites for immunopotentiation by synthetic glycopeptides.
Mesoporous silicate materials as substrates for molecular machines and drug delivery

Abstract Mesoporous silica thin films and nanoparticles prepared by surfactant-templated sol–gel techniques are versatile substrates that can be easily derivatized with active molecules to create functional materials. By exploiting the chemical and physical differences that exist in different regions of the mesostructure, active molecules can be deliberately placed using one-pot techniques, or they can be tethered to the exposed surfaces post-synthetically. The methods available for functionalization have been used to design operational machines including nanoimpellers based on the dynamic photoisomerization of azobenzene, and nanovalves based on the switchable motion of supramolecular rotaxanes and pseudorotaxanes. The ability of nanoimpellers and nanovalves to control the release of molecules from the pores of mesoporous silica materials is demonstrated using luminescence spectroscopy. These machines can be designed to operate under a range of external stimuli, including light, electrical (redox) or chemical (pH, competitive binding) energy, making them useful systems for a variety of controlled release applications. Mesoporous silica nanoparticles not functionalized with molecular machines are capable of delivering water-insoluble anticancer drugs to cancer cells. Carefully designed nanoimpellers and nanovalves supported on mesoporous silica nanoparticles offer the ability to develop sophisticated drug delivery vehicles for a wide range of drug molecules.
Neural activity and the development of the somatic sensory system

Present thinking about the role of neural activity in the developing brain is based largely upon observations in the visual system. Attempts to generalize these findings in the somatic sensory system, however, have yielded perplexing results. Unlike the visual system, recent evidence suggests that activity plays a relatively minor role in establishing structural patterns in the primary somatic sensory cortex. Activity levels in the primary somatic sensory cortex are nonetheless highest in those regions that grow most during postnatal development, implying that activity promotes differential cortical growth.
Intracellular calcium and survival of tadpole forebrain cells in anoxia

The frog brain survives hypoxia with a slow loss of energy charge and ion homeostasis. Because hypoxic death in most neurons is associated with increases in intracellular calcium ([Ca2+]i), we examined the relationship between [Ca2+]i and survival of a mixed population of isolated cells from the forebrain of North American bullfrog Rana catesbeiana tadpoles. Forebrain cells from stage V-XV tadpoles were isolated by enzymatic digestion and loaded with one of three different calcium indicators (Fura-2, Fura 2-FF and BTC) to provide estimates of [Ca2+]i accurate at low and high [Ca2+]i. Propidium iodide (PI) fluorescence was used as an indicator of cell viability. Cells were exposed to anoxia (100% N2) and measurements of [Ca2+]i and cell survival made from 1 h to 18 h. Intracellular [Ca2+] increased significantly after 3-6 h anoxia ( P <0.05), regardless of the type of Ca2+ indicator used; however, there were substantial differences in the measurements of [Ca2+]i with the different indicators, reflecting their varying affinities for Ca2+. Resting [Ca2+]i was approximately 50 nmol l-1 and increased to about 9-30 μmol l-1 after 4-6 h anoxia. The significant increase in [Ca2+]i during anoxia was not associated with significant increases in cell death, with 85-95% survival over this time period. Cells exposed to anoxia for 18 h, or those made anoxic for 4-6 and reoxygenated for 12 h to 16 h, had survival rates greater than 70%, but survival was significantly less than normoxic controls. These results indicate that large increases in [Ca2+]i are not necessarily associated with hypoxic cell death in vertebrate brain cells.
PERCEPTIONS OF EMPLOYEES' PARTICIPATION PROGRAMS IN UNION AND NONUNION SETTINGS '

A study was conducted to compare the perceptions of executives who manage organizations that have unions versus those that do not. 254 respondents indicated on a survey of organizational practice to what extent they observed activities indicative of success concerning employees' participation, work teams, total quality, core competencies, and human capital strategies. Analysis indicated that executives who manage firms affiliated with unions rated significantly higher items representing employees' participation, core competencies, work teams, and human capital strategies. No differences were found for the dimension of total quality. Results and implications are discussed.
The Brown Legacy and the O’Connor Challenge:Transforming Schools in the Images of Children’s Potential:

The gap between Blacks and Whites in educational outcomes has narrowed dramatically over the past 60 years, but progress stopped around 1990. The author reviews research suggesting that increasing the quantity and quality of schooling can play a powerful role in overcoming racial inequality. To achieve that goal, he reasons, our knowledge of best instructional practice should drive our conceptions of teachers’ work, teachers’ expertise, school leadership, and parent involvement. The research agenda supporting this paradigm connects developmental science to instructional practice and school organization and requires close collaboration between practitioners and researchers in a relentless commitment to provide superb educational opportunities to children whose future success depends most strongly on schooling.
Protein simulations using techniques suitable for very large systems: The cell multipole method for nonbond interactions and the Newton‐Euler inverse mass operator method for internal coordinate dynamics

two new methods developed for molecular dynamics simulations of very large proteins are applied to a series of proteins ranging up to the protein capsid of tomato bushy stunt virus.
POWER IN SOCIAL ORGANIZATION AS THE SUBJECT OF JUSTICE

Abstract: The paper suggests that the state is subject to assessment according to principles of social justice because state institutions or practices exercise forms of power over which no particular person has control. This rationale for assessment of social justice equally applies to legally optional or informal social practices. But it does not apply to individual conduct. Indeed, it follows that principles of social justice cannot provide a basis for the assessment and guidance of individual choice. The paper develops this practice-based conception of the subject of justice by rejoining G. A. Cohen's influential critique of Rawls’ focus on the “basic structure” of society.
Analysis of Low Energy Sputtering.

It is postulated that for low-energy sputtering the interatomic energy and distance relation can be represented by a Morse curve, and that the energy transfer in the lattice proceeds essentially by two-particle (i.e., binary) collisions.Based on these assumptions, a two-collision sputtering mechanism near the threshold is described. Under optimum energy transfer conditions, the analysis of this process gives the ion energy for a sputtering threshold of a surface particle tied by $N$ bonds.It is shown further that under a prolonged ion bombardment a surface contains particles with a number of bonds $N$, ranging from a maximum determined by a complete surface to a minimum determined by inaccessible bonds to underlying surface layers.Based on this information, the form of the sputtering yield-energy function is derived, consisting of a parabolic and a linear part. Predicted and experimental Pt-${\mathrm{Hg}}^{+}$ curves are compared, and the agreement is excellent.Two thresholds are defined: the lower threshold is the actual intercept of the yield curve, whereas the upper threshold corresponds to the intercept of the linear part of the yield curve. The two thresholds are computed for 20 metals bombarded by the ${\mathrm{Hg}}^{+}$ ion. The agreement with experimental values and the empirical threshold formula of Wehner is satisfactory.
Investigation of the transition from tunneling to impact ionization multiplication in silicon p-n junctions☆

White noise spectra of diodes breaking down between 1·5 and 5 V have been used to investigate the details of the transition from tunneling to avalanche breakdown in silicon p-n junctions. It is found that the transition and carrier multiplication in these junctions is dominated by the influence of the threshold energies for ionization. Because this influence is not explicitly taken into account in the existing theories of carrier multiplication and noise, they are not applicable to low breakdown voltage diodes. Consequently, a multiplication onset model and alternate schemes for calculating the DC multiplication and noise in low breakdown voltage diodes are developed. Analysis of the noise data indicates that the threshold energies for ionization depend slightly on junction widths and, for the diodes employed in this study, range between 1·66–1·9 eV for electrons and 1·79–2·04 eV for holes. The minimum distance between ionizing collisions is found to range from 190 to 240 A for electrons and 200 to 250 A for holes. Application of the threshold energies for ionization to the multiplication onset model permits evaluation of the doping densities on both sides of the step junctions. From it, it is determined that the solubility of aluminum in silicon is NA = 9·5 ± 0·5 × 1018 cm−3.
Evaluation of a finite element based crack-closure method for calculating static and dynamic strain energy release rates

Abstract A finite element based crack-closure integral for determining strain energy release rates for two-dimensional elastostatic and elastodynamic crack problems in finite bodies is evaluated. Both the J- integral and crack-closure integral are used to obtain strain energy release rates from the finite solution. Comparison with existing solutions shows that both methods yield very good results. However, the crack-closure integral can directly yield strain energy release rates and stress intensity factors for separate fracture modes in mixed-mode problems, and is very convenient to use in propagation crack problems.
Aliphatic Polyesters. III. Molecular Weight and Molecular Weight Distribution in Alcohol- Initiated Polymerizations of e-Caprolactone

The effect of initiation of ϵ-caprolactone polymerization with mono- and polyfunctional alcohols was investigated. The resulting linear and starshaped polymers were characterized by measurement of the molecular weight and molecular weight distribution. The polymerizations were characterized by (1) rapid initiation, (2) invariance of the number of growing chains corresponding to the amount of initiator, and (3) a dominant role played by ester interchange reactions.
Immobilization of chondroitin sulfate for the fabrication of biomimetic brush structures

Intervertebral disc (IVD) degeneration is accompanied by a loss of proteoglycans (PGs) in the nucleus pulposus (NP), resulting in a loss of charged chondroitin sulfate (CS) chains, decreasing mechanical function of the disc. PG mimics may be employed to restore NP functionality. Synthesis of CS bottle brush structures requires immobilization of CS at its terminal end. In this study, we have investigated commercially available CS for use in CS bottle brush synthesis. A primary amine (PA) at the terminal end of CS was identified and utilized to conjugate amine-reactive monomers to CS. Conjugation of monomers to CS was confirmed using the fluorescamine assay. Percent PA conjugations of 26%, 80% and 99% were seen for acrolein, acrylic acid and allyl glycidyl ether respectively. CS was also immobilized onto epoxy and aldehyde functionalized surfaces via the CS terminal primary amine. CS attachment was determined by monitoring changes in substrate sulfur content (energy-dispersive X-ray EDAX microanalysis) and surface wettability (contact angle). The modification and immobilization of CS demonstrated here will facilitate the synthesis of CS bottle brush PG mimics.⋆
THE RATE OF ALLELISM OF LETHAL GENES IN A GEOGRAPHICALLY STRUCTURED POPULATION

The expected rate of allelism, E [ I ( x )], of lethal genes between two colonies with distance x in a structured population is studied by using one-and two-dimensional stepping-stone models. It is shown that E [ I ( x )] depends on the magnitude of selection in heterozygous condition ( h ), the rate of migration among adjacent colonies ( m ), the number of loci which produce lethal mutations ( n ) and the effective population size of each colony ( N ).—— E [ I ( x )] always decreases with distance x . The rate of decrease is affected strongly by the magnitude of m . The rate of decrease is faster when m is small. E [ I ( x )] also decreases with increasing N and n . The effect of h on E [ I ( x )] is somewhat complicated. However, E [ I ( O )] is always smaller when h is small than when it is large.——For large x , the following approximate formulae may be obtained: ![Formula][1] where ![Graphic][2] and Var ( q ) are the mean and the-variance of gene frequencies in each colony, t is approximated as t = h , 2√ u ; — h for the partially recessive, completely recessive, and overdominant lethals, respectively, and C O is a function of m and t . It is clear that E [ I ( x )] declines exponentially with x in a one-dimensional habitat. The decrease E [ I ( x )] is faster in a two-dimensional habitat than in a one-dimensional habitat. The present result is applied to some of the existing data and the estimation of population parameters is also discussed. [1]: /embed/graphic-1.gif [2]: /embed/inline-graphic-1.gif
A New Interleaved Series Input Parallel Output (ISIPO) Forward Converter With Inherent Demagnetizing Features

A forward converter of interleaved series input and parallel output (ISIPO) structure is proposed in this paper. Theoretical analysis indicates that by using two auxiliary diodes and the unique architecture, the proposed ISIPO forward converter can realize natural magnetizing reset, the leakage and magnetizing energy in the transformers can be recycled, and the voltage stress on each switch is clamped at . In addition, by parallel connection of the transformers, the output rectifier and filters can distribute power losses and thermal stresses of the transformers and semiconductors, and the interleaved operation can reduce the current ripple in output capacitors. All these features make the proposed forward converter suitable for dc-dc converters with high input voltage, high output current, and high power density. The theoretical analysis is verified by a 1000 W experimental prototype.
Reply to Comment on ‘Analytical solution of non-homogeneous anisotropic wave equations based on differential transfer matrices’

In reply to the Comment by Lakhtakia (2003 J. Opt. A: Pure Appl. Opt. 5 432–3), the conditions under which the differential transfer matrix method is exact are discussed.
Ladder Network Calculations

A program is described that will analyze most ladder networks considered for communications systems. With each branch consisting of four elements, the input impedance, transfer impedance, voltage transfer ratio, insertion loss, and group delay for five branches can be analyzed with a TI-58 calculator.
Evaluation of an Academic Family Therapy Training Program: Changes in Trainees' Relationship and Intervention Skills.

Students in an academic training program were assessed for changes in their relatwnship and intervention skills following completion of the program. Positive improvements were found on some measures but not all. Additionally, trainee variables such as previous clinical experience, gender, age, marital status, and scores on standardized admissions tests were examined in relation to trainees’ skills changes. Trainee characteristics were unrelated to changes in intervention skills. However, a number of relationships were found between trainee characteristics and changes in relatwnship skills. This study examined the question of whether trainees in a two-year, master’s degree program in marital and family therapy changed over the course of training. Despite a number of attempts to assess various components of family therapy training, only one other study has evaluated trainees’ changes after completing an entire 2-year program of intensive study (Perlesz, Stolk, & Firestone, 1990). One other study examined trainees’ changes after completing the first year of a 2-year program (Tucker & Pinsof, 1984). Both of these studies were conducted in postgraduate degree programs rather than an academically based program. Most studies have examined training sequences or workshops conducted in community-based mental health agencies (e.g., Byles, Bishop, & Horn, 1983; Churven & McKinnon, 1982; Pulleyblank & Shapiro, 1986) or evaluated various components of a given training program. These include evaluations of the acquisition of skills following a course in structural family therapy (Zaken-Greenberg & Neimeyer, 1986) and comparisons of different methods for teaching specific family therapy skills (Fenell, Hovestadt, & Harvey, 1986; Mohammed & Piercy, 1983; Tomm & Leahey, 1980). The absence of documentation for the effectiveness of academically based family therapy programs is startling given the proliferation of such programs and the efforts devoted to developing standards for the evaluation and accreditation of these programs (Commission on Accreditation, 1988).
Giant enhancement of stimulated Brillouin scattering in the sub-wavelength limit

We show that the nature of stimulated Brillouin scattering (SBS) radically changes at nanoscales due to tremendous internal radiation pressures. Coherent interplay between radiation pressure and electrostriction yields giant enhancement of SBS and tailorable photon-phonon coupling.
Evaluation of negative viscosity as upper extremity training for stroke survivors

With stroke survivors (n=30) as the test population, we investigated how upper extremity training with negative viscosity affects coordination in unassisted conditions. Using a planar force-feedback device, subjects performed exploratory movements within an environment that simulated 1) negative viscosity added to elbow and shoulder joints 2) augmented inertia to the upper and lower arm combined with negative viscosity, or 3) a null force field (control). After training, we evaluated each subject's ability to perform circular movements in the null field. Negative viscosity training resulted in greater within-day reductions in error compared with the combined field training. Negative viscosity promoted greater distributions of accelerations during free exploration, especially in the sagittal axis, while combined field training diminished overall activity. Both force field training groups exhibited next day retention, while this was not observed for the control group. The improvement in performance suggests that greater range of kinematic experiences contribute to learning, even despite novel force field environments. These findings provide support for the use of movement amplifying environments for upper extremity rehabilitation, allowing greater access to training while maintaining user engagement.