cssi/SciSciGPT-SciSciNet huggingface dataset:
On the nucleation of amyloid β-protein monomer folding

Neurotoxic assemblies of the amyloid β-protein (Aβ) have been linked strongly to the pathogenesis of Alzheimer’s disease (AD). Here, we sought to monitor the earliest step in Aβ assembly, the creation of a folding nucleus, from which oligomeric and fibrillar assemblies emanate. To do so, limited proteolysis/mass spectrometry was used to identify protease-resistant segments within monomeric Aβ(1–40) and Aβ(1–42). The results revealed a 10-residue, protease-resistant segment, Ala21–Ala30, in both peptides. Remarkably, the homologous decapeptide, Aβ(21–30), displayed identical protease resistance, making it amenable to detailed structural study using solution-state NMR. Structure calculations revealed a turn formed by residues Val24–Lys28. Three factors contribute to the stability of the turn, the intrinsic propensities of the Val-Gly-Ser-Asn and Gly-Ser-Asn-Lys sequences to form a β-turn, long-range Coulombic interactions between Lys28 and either Glu22 or Asp23, and hydrophobic interaction between the isopropyl and butyl side chains of Val24 and Lys28, respectively. We postulate that turn formation within the Val24–Lys28 region of Aβ nucleates the intramolecular folding of Aβ monomer, and from this step, subsequent assembly proceeds. This model provides a mechanistic basis for the pathologic effects of amino acid substitutions at Glu22 and Asp23 that are linked to familial forms of AD or cerebral amyloid angiopathy. Our studies also revealed that common C-terminal peptide segments within Aβ(1–40) and Aβ(1–42) have distinct structures, an observation of relevance for understanding the strong disease association of increased Aβ(1–42) production. Our results suggest that therapeutic approaches targeting the Val24–Lys28 turn or the Aβ(1–42)-specific C-terminal fold may hold promise.
China’s Nuclear Forces and the Stability of Soviet-American Deterrence

The first obvious fact about China’s nuclear force is how little is known about it in the West. The second is the asymmetry of its apparent impact on the nuclear balance. There is little to suggest that China’s missiles target any country but the Soviet Union, but to some extent ambiguity about her nuclear forces must be calculated Chinese strategy. For the Soviet Union in particular, such uncertainty must play on her deep-rooted anxiety about China.
Analysis of rib dielectric waveguides

An analysis of rib dielectric waveguides based on a mode matching technique is presented. When the constituent slab guides support only one guided mode, it is shown that the cutoff condition for the higher order modes is the same as the result of the effective dielectric constant method. However, when the rib region is thick enough to support two guided slab modes, the cutoff conditions are significantly different. For this case universal design curves are produced and plotted. The results are also compared with another theory that exists to analyze such structures.
Synergistic effects of human B and T lymphocyte mitogens induce uniform, high levels of immunoglobulin secretion among normal donors.

Abstract Synergistic effects of B-cell mitogen Staphylococcus bacteria strain Cowan I (Cowan I) plus T-cell activator pokeweed mitogen (PWM) in generating immunoglobulin-secreting cells (ISC) from human peripheral blood mononuclear cells (MNC) were investigated. ISC were assayed by reverse plaque-forming cells using protein A-coated red blood cells. Low concentrations of PWM plus Cowan I gave superadditive effects on ISI induction, generating 3–20 times as many ISC as optimal amounts of either mitogen alone. The mitogens together and separately showed similar kinetics of ISC; synergy was observed at every day tested. IgM ISC represented 10% of initial MNC from all cell donors tested even if the donors were low responders to either mitogen alone. The numbers of ISC obtained are higher than previous reports and more uniform among donors, making this a superlative method for studies on normal human immunoglobulin secretion.
Reducing the prevalence of anxiety in children and adolescents: an evaluation of the evidence base for the FRIENDS for Life program

Current estimates suggest that between 8 and 22% of children and adolescents may suffer from an anx- iety disorder. Effective intervention efforts are therefore clearly needed to reduce the likelihood of anxious symp- toms and promote healthy functioning. One intervention that appears feasible for use in schools and was designed to target anxiety symptoms is the FRIENDS for Life program. Evaluation of FRIENDS has been limited in the United States; however, criteria for evaluation of such programs are available. Thus, the purpose of this paper is to review the research base regarding the FRIENDS for Life program and apply coding procedures to examine program effec- tiveness. Overall, results suggested promise for use in school-based settings, given demonstrated effectiveness in reducing anxiety symptoms in both universal and targeted populations when implemented within the school ecology. Limitations of the existing evidence base, however, are discussed, thus providing direction for future research.
Seizures Precipitated by the Use of Language: A Review

Summary The available literature pertaining to cases of epilepsy in which the use of language, i.e., reading, writing or speaking, appears to precipitate the seizures has been reviewed. The hypothesis of other authors that proprioceptive feedback constitutes the essential triggering mechanism has been re-evaluated and rejected. It is suggested instead that language itself can function as a conditional stimulus in the formation of a “reflex epilepsy.”
Hydroformylation of 1-Octene under Atmospheric Pressure Catalyzed by Rhodium Carbonyl Thiolate Complexes Tethered to Silica

The silica-tethered rhodium thiolate complex catalysts Rh−S/SiO2 and Rh−S−P/SiO2 were prepared by the condensation of SiO2 with Rh2[μ-S(CH2)3Si(OCH3)3]2(CO)4 (Rh−S) or Rh2[μ-S(CH2)3Si(OCH3)3]2[Ph2P(CH2)3Si(OC2H5)3]2(CO)2 (Rh−S−P). These tethered complex catalysts exhibit high activity for the hydroformylation of 1-octene in the presence of phosphine donor ligands under the mild conditions of 60 °C and 1 atm. IR (DRIFT) spectral studies of the catalysts used indicate that tethered monorhodium dicarbonyl thiolate complexes of the type Rh(SR)(CO)2(PR‘3) are the predominant species on the surface for the catalysts that have the highest hydroformylation activity. The catalysts are easily separated from the reaction mixtures, and the Rh−S/SiO2 catalyst maintains its activity through at least three cycles over a total period of 69 h, during which time there are 1273 (mol of aldehyde/mol of Rh) turnovers. Effects of the phosphine ligand and PR‘3/Rh mole ratio on the hydroformylation rate, conversion, and chemo- a...
A generalized self-consistent mechanics method for composite materials with multiphase inclusions

A generalized self-consistent method (GSCM) based on energy equivalence and an inclusion matrix-composite model is proposed that has applicability to composites with three or more phases. For a solid containing single-phase reinforcements, the present approach is equivalent to the inclusion-matrix-composite model. Both particulate-reinforced and unidirectional fiber-reinforced composites are investigated. For a multiphase composite with a phase volume fraction of c1,c2,c3, …, it is found that the effective moduli are approximately decoupled such that Ē(c1,c2,c3, …) / E = Ē0(c1)/E × Ē0c2/E × Ē0(c3/E × …, where Ē0(·) is the closed-form effective moduli of the correspondin composites with single-phase reinforcements, and E is the moduli of the matrix material. Compared with experimental data and results from numerical studies, the current approach provides reasonably accurate predictions for the effective moduli of multiphase composites.
Circadian variations in plasma renin activity, catecholamines and aldosterone during exercise in women.

Four women were studied at 0400 h and 1600 h to determine if their hormonal and hemodynamic responses to exercise varied with the circadian cycle. Esophageal temperature was measured during rest and exercise (60% peak $$\dot V_{{\text{O}}_{\text{2}} } $$ ; 30 min) in a warm room (T a=35° C; $$P_{{\text{H}}_{\text{2}} {\text{O}}} = 1.7$$ =1.7 kPa). Venous blood samples were drawn during rest and exercise and hemoglobin concentration (Hb), hematocrit (Hct), plasma osmolality (P osm), plasma protein concentration (P p), colloid osmotic pressure (COP), plasma renin activity (PRA), cortisol, aldosterone, norepinephrine (NE) and epinephrine (E) were determined. Changes in plasma volume (PV) were estimated from changes in Hb and Hct. The relative hemoconcentration (−11.2%) was similar at 0400 h and 1600 h, but the absolute PV was smaller at 1600 h than at 0400 h (p=0.03). The responses ofP osm,P p and COP to exercise were unaffected by time of day. Although PRA was not different at the two times of day, PRA was 244% greater during exercise at 1600 h, but only 103% greater during exercise at 0400 h. The normal circadian rhythms in plasma aldosterone (p=0.043) and plasma cortisol (p=0.004) were observed. Plasma aldosterone was 57% greater during exercise, while plasma cortisol did not change. The change in E and NE was greater at 0400 h, but this was due to the lower resting values of the catecholamines at 0400 h. These data indicate that time of day generally did not affect the hormonal or hemodynamic responses to exercise, with the exception that PRA was markedly higher during exercise at 1600 h compared to 0400 h.
Chronic Family Economic Hardship, Family Processes and Progression of Mental and Physical Health Symptoms in Adolescence.

Research has documented the relationship between family stressors such as family economic hardship and marital conflict and adolescents’ mental health symptoms, especially depressive symptoms. Few studies, however, have examined the processes whereby supportive parenting lessens this effect and the progression of mental health and physical health symptoms in adolescence. The present study investigates the influences of chronic family economic hardship on adolescents’ multiple health problem symptoms (i.e., symptoms of anxiety, and depression and physical complaints) through parents’ marital conflict, and supportive parenting; it also examines how there adolescents’ health problems mutually influence one another throughout adolescence. We used Structural Equation Modeling to analyze data from a longitudinal sample of European American mothers, fathers, and target adolescents (N = 451, 53 % female) to examine direct and indirect effects. Findings generally supported the hypothesized model. Chronic family economic hardship contributed to mental and physical health problems of adolescents. This influence largely was mediated through supportive parenting. Moreover, supportive parenting buffered marital conflict on depressive symptoms of adolescents. Also, there was a tendency for females to show more stable depressive symptoms than males. The study demonstrates key mediating pathways and additional moderating influences based on the family stress model and also highlights the importance of improving health resources for adolescents.
Determination of absolute atomic transition probabilities using time resolved optical pumping

Abstract We describe a method of determining atomic transition probabilities by independently measuring branching ratios and radiative lifetimes. These quantities are directly determined by time resolved optical pumping. The technique has been applied to the measurement of gA values for particular transitions in 238U I.
Inhibition of Rabbit Muscle Adenylate Kinase by Vitamin C

Abstract Rabbit muscle adenylate kinase (EC 2.7.4.3) is completely inhibited, or nearly so, at 2 mMascorbate, concentrations that are found in tissues. Kinetically, the inhibitions show classic non-competitive inhibition patterns against both substrates. Ascorbate inhibitions reverse completely in the presence of low concentrations of sulfhydryl compounds, such as mercaptoethanol, dithiothreitol, cysteine and glutathione. Dehydroascorbate inhibition is relatively poor and is also reversed by sulfhydryl compounds. Examination of the adenylate kinase inhibited by ascorbate with CD methodology showed no significant change in α-helix and s-pleated sheet composition.
Molecular details of formin-mediated actin assembly

Formins are a large family of multi-domain polypeptides that form homodimers. The highly conserved formin homology 2 (FH2) domain and its neighboring formin homology 1 (FH1) domain, which are surrounded by regulatory domains, cooperate in rapidly assembling profilin-actin into long filaments while remaining continuously associated with the fast-growing barbed end. Recent biochemical, biophysical, theoretical and structural studies have concluded that diverse formins are mechanistically similar, but that the rates of various assembly states differ quantitatively, and have shed light on the mechanism of formin auto-regulation and activation by Rho GTPases.
A philosophical inquiry into the moral sense of nature and artifacts

These inquiries do not diminish or overshadow the power and importance of the gift that isThe Embers and the Stars. It must be counted among the richest, most eloquent, original, and challenging new works of philosophy to appear in recent years, standing alongisde the best of the authors Kohak admires most, like Marcel and Ricoeur. It must be read. Moreover, we must press Kohak for both the philosophical theology and philosophical inquiry into the moral sense of artifacts toward which this work points. Once there was a man, once there was a raccoon, once there was a work. That is the miracle, that is the point.
Moving salt sills and hydrocarbon maturity

Salt sills have been observed in the Gulf Coast. The contrast in the thermal conductivity between salt and detrital sediments means that a salt sill focuses heat around its leading edge, resulting in the devlopment of an anomalous temperature pattern in the vicinity of the salt sill. The consequent anomaly in thermal maturity pattern for hydrocarbons is related to four parameters: the salt sill thickness; the subsurface depth of the sill; the inclination of the sill; and the salt speed through the sediments. The excess maturity in the vicinity of the salt sill is shown to be dominantly dependent on the velocity of the salt sill. The positional influence of the hydrocarbon maturity relative to the salt is also examined and it is shown that the alteration of sedimentary burial paths by the inserted salt also causes a thermal anomaly. Both thermal focusing of heat by salt and sediment burial to a different thermal regime caused by passage of inserted salt produce thermal maturity effects comparable in magnitude, and neither may be ignored.
Effect of fuel structure on pathways to soot

The influence of fuel structure on chemical reaction pathways leading to soot was investigated using detailed kinetic models for the conditions of shock-tube pyrolysis of 1,3-butadiene, benzene and ethylene. It was found that reaction pathways to soot relax to the previously identified acetylene-addition mechanism in each case. Fuel molecular structure influences the growth process only at its early stages, first by providing more efficient reaction partners for the formation of aromatic molecules and second by affecting the generation of hydrogen atoms. The model explains the relative sooting tendencies of these fuels for shock tube pyrolysis conditions and agrees with recent observations in laminar diffusion flames.
Lie Isomorphisms in Prime Rings with Involution

Abstract Let R and R ′ be prime rings with involutions of the first kind and with respective Lie subrings of skew elements K and K ′. Furthermore assume ( RC : C ) ≠ 1, 4, 9, 16, 25, 64, where C is the extended centroid of R . It is shown that any Lie isomorphism of K onto K ′ can be extended uniquely to an associative isomorphism of 〈 K 〉 onto 〈 K ′〉, where 〈 K 〉 and 〈 K ′〉 are respectively the associative subrings generated by K and K ′.
Bleaching of rhodopsin by light and by heat.

EVER since Mirsky1 suggested that the bleaching of rhodopsin by light involves the reversible denaturation of its protein moiety, opsin, analogies have been drawn between bleaching and denaturation of the visual pigments. This notion derives its strongest experimental support from the apparent agreement between the minimum size of quantum required to bleach frog or cattle rhodopsin with light2 (48,500 cal./mole) and the Arrhenius activation energy (E a) for the thermal bleaching of frog rhodopsin3 (44,000 cal./mole). We find that this analogy breaks down on closer examination, and that light and heat bleach rhodopsin by different mechanisms, yielding different products.
Jewish-Muslim Veneration at Pilgrimage Places in the Holy Land

For millennia human communities have designated certain sites as sacred and nowhere more so than in the Holy Land. The Bible records that Canaanites worshipped in “high places,” and the prophets railed against the Israelites for continuing the practice. Jesus castigated the Pharisees for adorning the tombs of the prophets. When Jews were expelled from Jerusalem, those who remained on the land did not abandon their devotion to the holy sites. When the Muslims arrived they continued the practice of visiting the tombs of those figures mentioned in both the Bible and the Quran. Throughout the Middle Ages and into the modern period Muslims and Jews wrote about their visits to these jointly-venerated tombs. Jews made illustrated scrolls, wall hangings, and other works of art depicting these sites, representing the shrines with prominent Islamic crescents on top, an indication that Jewish viewers felt no discomfort at the use of this iconography. The Jewish valorization of the Islamic crescent atop shrines common to Jews and Muslims reflects a relationship very different from that existing between the two cultures today.
Transition from cataclastic flow to dislocation creep of feldspar: Mechanisms and microstructures

Feldspar aggregates exhibit cataclastic flow over a wide range of conditions between low-temperature faulting and high-temperature dislocation creep; this is due to the ease of cracking on the two good cleavages and the difficulty of dislocation motion. Albite aggregates experimentally deformed at moderate to high pressures in the cataclastic flow regime are macroscopically ductile; their optical microstructures show little evidence of crushing and resemble those expected for dislocation creep. However, transmission electron microscopy (TEM) shows no dislocations or very limited dislocation mobility, but does show abundant distributed microcracks and microcrush zones that contain <0.1-µm-diameter grains. Cataclastic flow is likely to be an important deformation mechanism in nature, but it may have been overlooked because its optical microstructures have been misinterpreted and because the extreme grain size reduction facilitates transitions to other phases and deformation mechanisms.
Age-related differences in cerebral blood flow underlie the BOLD fMRI signal in childhood

Functional magnetic resonance imaging (fMRI) has become a premiere technique for studying the development and neural mediation of a wide range of typical and atypical behaviors in children. While the mechanism of the blood oxygen level-dependent (BOLD) fMRI signal has been a focus of investigation in the mature brain, it has been largely unexamined in the developing brain. One critical component of the BOLD signal that has been noted to change with age is cerebral blood flow (CBF). Reports of CBF in children based on clinical radioactive tracing methods have found elevated CBF in childhood relative to adulthood, which could affect the BOLD response. This study used non-invasive arterial spin labeling magnetic resonance imaging to study resting state and activity-driven CBF in conjunction with the functional BOLD response in healthy children 8 and 12 years of age and in adults. Participants performed a finger-tapping task to generate robust activation measured in the motor cortex. Quantification of resting state CBF demonstrated higher CBF in 8 year olds and in 12 year olds relative to adults. The absolute increase in CBF between baseline rest and peak response during the motor task was also higher in both child groups compared to adults. In contrast, the relative increase of CBF above baseline, expressed as percent of CBF change, was comparable across groups. The percent of BOLD signal change was also stable across age groups. This set of findings suggests that along with elevated CBF in childhood, other component processes of the BOLD response are also in an elevated state such that together they yield a net BOLD effect that resembles adults. These findings coincide with our previous examination of hemodynamics in primary sensory cortex. Although the magnitude of the BOLD response appears consistent between childhood and adulthood, the underlying physiology and cerebrovascular dynamics that give rise to the BOLD effect differ between immature and mature neural systems.
Functional properties of the human atrioventricular and intraventricular conduction system during premature atrial stimulation

Premature atrial stimulation combined with His bundle and local ventricular electrograms was used in three patients to analyse complex AV conduction patterns resulting from variable degrees of delayed or enhanced propagation within the atria, A-V node, and ventricular specialized conducting system. The St1-St2 intervals were plotted against the corresponding responses at the low right atrium (LRA), His bundle, intitial site of ventricular depolarization (V), right ventricular apex (RVA), and posterosuperior wall of left ventricle (LV). The electrophysiological effects of a β-blocking agent, Alprenolol, were studied in two patients. This drug, at a dose of 0·2 mg/kg, increased the effective and functional refractory periods of the atria and AV node. In the presence of bifascicular blocks the effective refractory period of the ventricular specialized conducting system was also lengthened. Different grades of functional bilateral bundle branch block were detected in one case. The amount of delay in each bundle branch block could not be determined from the surface leads alone. A supernormal phase of intra-atrial conduction occurred in one patient. These studies extend the usefulness of intracardiac recordings in understanding otherwise complex electrophysiological phenomena in the human heart.
Competition between juveniles and adults in age-structured populations

Abstract The effect of competition between juveniles and adults is examined in a generalized, two-age-class, discrete-time model. Adult fecundity and juvenile survival are functions of both age-class densities. Possible configurations of the zero growth isoclines are examined, giving special attention to the isocline shapes, the number of equilibria, and the manner in which the population approaches these equilibria. It is found that small increases in the density of one age class may have either a positive or a negative effect on recruitment into the other class, depending upon the degree of density dependence in fecundity and survival. Closely allied to this, an increase in the resources for a given age class may result in either an increase or a decrease in its equilibrium density. Strong juvenile-adult competition generally has destabilizing effects on the population's equilibrium, with the system being more sensitive to juveniles competing with adults than to the reverse.
Orientation of homing pigeons: Direct sight of sun not necessary

Homing pigeons do not need to see the sun directly in order to orient in a Kramer-type cage. Five homing pigeons were directionally trained in the traditional manner with a clear view of the sky and sun overhead. They were then tested while wearing a sun shade which prevented them from seeing any of the sky out of the top of the cage. All of the birds were able to maintain their orientation. Shadows on the floor of the apparatus may have provided cues. These results suggest a mechanism pigeons may use to obtain information from the sun, that is, by looking at shadows on the ground. Experiments of a similar nature with free-flying birds are needed.
Unstable slit flow of a liquid crystalline polymer solution

A lyotopic solution of 27 wt% hydroxypropylcellulose [HPC] in m-cresol has been studied in pressure-driven slit flow. At high flow rates an instability leads to large wavelength disturbances in fluid structure. A combination of image analysis and time signal processing is used to determine the velocity at which the structural disturbances are convected downstream, which is shown to be equal to the independently measured and predicted centerline velocity. This implies that the disturbance structure is confined near the midplane of the slit flow. Upstream of the onset point of the wavy fluid structures, the fluid exhibits unusual optical properties when viewed between crossed polarizers that are rotated relative to the flow direction. Specifically, the optical properties indicate that there must be some variation in the macroscopic optical axis of the sample as light passes through the slit flow. A discrete optical model consisting of birefringent elements twisted away from and back to the flow direction as a function of depth in the sample is able to predict the essential optical characteristics; however, independent x-ray scattering measurements show that the macroscopic molecular alignment is along the flow direction. The wavy textures apparently emerge as a result of an inhomogeneous transition of orientation back to the flow direction, trapping thin bands of fluid in the twisted configuration.
Examining the Role of Innovation Diffusion Factors on the Implementation Success of Enterprise Resource Planning Systems

Abstract Enterprise resource planning (ERP) systems have been adopted by many organizations in the past decade. These systems have revolutionized organizational computing by facilitating integrated and real-time planning, production, and customer response. While some companies have achieved significant efficiencies through ERP, others have complained of failed implementations, budget overruns, and disappointing performance. This paper draws upon Diffusion of Innovation (DOI) theory and Information Systems Success (IS) theory to develop and test a model of ERP implementation success. Results reveal that top management support and training are positively related to user satisfaction, while perceived complexity of ERP and competitive pressure show a negative relationship. Consensus in organizational objectives and competitive pressure are positively associated with perceived organizational performance. Post hoc analysis identifies user satisfaction as a moderator between certain DOI characteristics and organizational performance. This leads to the proposal of a new model of ERP implementation for future research.
Time went by so slowly: Overestimation of event duration by males and females

In three experiments, 469 subjects watched a short videotape of a bank robbery and later estimated the duration of the tape. Subjects invariably overestimated the durations. Accuracy of time estimation was unrelated to amount of free recall (Experiment 1) or accuracy of memory (Experiment 2). Females overestimated to a greater degree than males (Experiments 2 and 3). A more stressful version of the event produced greater overestimates than a less stressful version (Experiment 3). The relationship between induced arousal and time estimation appears to be different for men and women.
On Adaptive Manual Control

Experimental studies and control descriptions of the human operator in recent years have extended the knowledge of adaptive behaviour in manual control from vague generalities about his versatility to quantitative descriptions. Considerable data have been gathered on the ability of the human to adapt to changes in input spectra, controlled element gain, polarity and dynamics, display modality, and the limits of controllability under a variety of situations. These results have indicated a greater adaptation versatility than expected from some earlier descriptions, but have also pointed out some of the restricted training conditions under which the rapid human adaptation may be expected to be demonstrated. When it comes to explaining how the human manages his remarkable adaptation abilities, less progress has been made. Improvements in the techniques for dynamic measurement of the adaptive process have been helpful in this regard but still fall short of what is required to observe the change in control law. Some appealing suggestions for detection models, model reference conitrol analogues and statistical decision theory pattern recognition algorithms have been put forth but are in no sense 'proven'. Primarily as a result of the measurement limitation and the lack of sufficient knowledge about adaptive control systems in general, the development of models for human adaptive control has been limited to general schema at this time.
Have Things Changed in Pharmacy Education

ABSTRACTA shift in focus from the product to the patient has occurred in pharmacy. Despite significant changes in pharmacy curricula, it is unclear if perceptions of the profession of pharmacy have changed accordingly. This commentary questions the presumption that, over time, there would be a change in perceptions to reflect this paradigm shift for which the literature revealed little evidence. We conclude that the ties between professional mandates and perceptions of the practice of pharmacy are loose at best and that further efforts are needed to secure pharmacy's role in a changing and increasingly interdisciplinary health care environment.
Modeling and Identification of a Class of Servomechanism Systems With Stick-Slip Friction

On tient compte de la friction de broutement dans la modelisation du processus. L'identification des parametres du systeme est formulee comme un probleme d'optimisation non lineaire
Effects of Coronary Bypass Surgery and Angioplasty On Coronary Blood Flow and Flow Reserve

M YOCARDIAL revascularization with an aortocoronary bypass graft or angioplasty is an effective means of reducing the symptoms of myocardial ischemia and normalizing previously positive tests of provokable myocardial ischemia. The effect of these procedures on coronary hemodynamics and their efficacy in restoring normal myocardial perfusion is less clear. Unlike studies performed in normal animals, the effects of the coronary revascularization in patients must be studied in the setting of coronary atherosclerosis, a pathologic process that is complex and variable in severity and distribution. Additionally, techniques for studying the effects of revascularization in humans (quantitation of coronary arterial geometry, measurement of coronary blood flow, and determination of the flow reserve capacity of revascularized arteries) suffer serious deficiencies. As a result, studies of the effects of revascularization procedures on coronary blood flow and coronary reserve should be interpreted cautiously, taking into account their many methodologic limitations. The purpose of this article is to define the limitations of current techniques for measuring coronary blood flow and flow reserve following revascularization, to review prior studies of the effects of coronary bypass surgery or angioplasty on coronary blood flow and flow reserve, and to elucidate what these studies tell us about the coronary circulation of humans.
How bidirectional becomes unidirectional.

High-throughput RNA sequencing has unveiled the existence of a large number of noncoding antisense RNAs derived from bidirectional promoters; unlike sense transcripts, these RNAs are often unstable. Two recent reports investigate why downstream transcription is productive, whereas upstream transcripts are prone to degradation, revealing that an asymmetric distribution of polyadenylation signals and U1 snRNP–binding sites surrounding transcription start sites control the outcome of bidirectional transcription.
Ischemic Colitis: An Unusual Case of Inferior Mesenteric Arteriovenous Fistula Causing Venous Hypertension. Report of a Case

Mesenteric arteriovenous fistulas are a rare entity. Those involving the inferior mesenteric artery are exceptionally rare with only 13 cases reported in the English literature,1,2 of which only one has been associated with ischemic colitis. Ischemic colitis is a well-recognized clinical entity that typically occurs spontaneously in elderly patients and is not associated with a specific clinical presentation.3 We report a case of ischemic colitis caused by venous hypertension associated with a congenital inferior mesenteric arteriovenous fistula. To our knowledge, this is the first reported case of a mesenteric arteriovenous fistula causing ischemic colitis in a patient without previous gastrointestinal surgery or trauma.
Isolated lower extremity monoplegia due to a traumatic intraparenchymal contusion: Report of two cases

Background: Isolated lower extremity monoparesis/monoplegia (MP) due to epidural or subdural haematomas near the vertex have not been reported due to traumatic intraparenchymal contusions. Due to the limitations of conventional axial computed tomographic (CT) imaging, the evidence of a vertex contusion may be under-appreciated if an overlying skull fracture is absent.Case description: Two cases of isolated MP due to vertex contusions are described and the physical forces involved in the head trauma are described to explain the location of the contusions. Vertex intraparenchymal contusions are rare because of the way the brain deforms in response to the accelerational forces acting on it during head trauma. This study analyses patients’ injuries and addresses the importance of considering the forces acting on the brain when evaluating a victim of head trauma.Conclusion: Isolated lower extremity MP following head trauma is rare because haematomas in the fronto-parietal cortex near the midline that could pro...
Shape memory epoxy: Composition, structure, properties and shape memory performances

Due to the intrinsic properties of polymers, medical applications have been the primary targets for the development of shape memory polymers (SMPs) exhibiting softness at body temperature, biocompatibility, high deformability, good shape recovery (Rr) and good shape fixity (Rf). However, there is an increasing need for developing smart materials that would meet the drastically different requirements imposed by applications where, instead, high strength well above room temperature, durability, stability, and high thermo-mechanical endurance are necessary. Here, we present results obtained on a series of shape memory (SM) epoxies that appear promising base materials for such applications. The influence of molecular and structural design on their physical and SM properties were studied. The impact of various SM programming conditions (i.e., deformation load, recovery heating rate, number of cycles, and isothermal holding times in the hot and cold deformed shapes) was also investigated. The instantaneous SM behavior was found similar for all the networks with Rf and Rr values nearing 100% above 6 to 7% strain. The SM performances strongly depended on the strain-dependent thermal expansion/contraction of the materials during thermo-mechanical cycling. Networks with lower crosslink density, higher chain flexibility and/or mobility showed reduced SM performances, further diminished by more stringent thermo-mechanical cycling conditions.
Climatological Hurricane Landfall Probability for the United States

Abstract This study examines the historical record of hurricanes and tropical storms in the Atlantic Ocean basin to determine the eventual landfall probability for the U.S. coastline based on the complete tracks of those storms. The current method for estimating empirical landfall probabilities is to report a frequency based on the number of storms affecting a region over a certain period of time. A spatial dimension is added in this study to determine which storms in all portions of the basin might ultimately strike the United States based on the historical record. For example, if a tropical cyclone is near the island of Puerto Rico, which portions (if any) of the U.S. coastline are most at risk of eventual landfall? A tessellation of hexagons is systematically evaluated, and eventual landfall probabilities are calculated for all storms passing through each hexagon. Probabilities are calculated and mapped for four individual states and for the United States as a whole. The maps show the spatial areas tha...
The effect of synchronous firing on the clustering dynamics of social amoebae

A discrete model for computer simulations of the clustering dynamics of social amoebae is presented. This model incorporates the wavelike propagation of extracellular signaling of 3'-5'-cyclic adenosine monophosphate cAMP, the sporadic firing of cells at early stage of aggregation, the signal relaying as a response to stimulus, and the inertia and purposeful random walk of the cell movement. It is found that the sporadic firing below the threshold of cAMP concentration plays an important role because it allows time for the cells to form synchronous firing right before the stage of aggregation, and the synchronous firing is critical for the onset of clustering behavior of social amoebae. A Monte-Carlo simulation was also run which showed the existence of potential equilibriums of mean and variance of aggregation time. The simulation result of this model could well reproduce many phenomena observed by actual experiments. © 2013 Wiley Periodicals, Inc. Complexity 20: 16-26, 2014
From Van der Waals' equation to the scaling laws

Abstract From our present-day perspective, the most important results obtained by Van der Waals for thermodynamic behavior in the critical region of gases are: the cubic critical isotherm and quadratic coexistence curve; the continuity of slope of the vapor-pressure curve; the law of the rectilinear diameter and the law of corresponding states. The critical behavior of Van der Waals' equation is typical for equations of state that are regular at the critical point in a sense to be discussed; those equations are presently called “classical”. The confrontation with experiment took place before 1900. At that time, the first power-law analyses of data were made and their results disproved classical theory convincingly. It took, however, another 65 years before classical theory was replaced by the scaling laws. The very limited validity of the law of corresponding states, however, never posed a serious threat to the classical equation. On the contrary, by generalizing this law in various ways, our insight into the relation between molecular interaction and thermodynamic behaviour has been deepend considerably. In a sense, the principle of universality may be considered the latest generalization of the law of corresponding states. The principle of continuity of slope of the vapor-pressure curve has been preserved; the direction of the vapor-pressure curve at the critical point is a very special one according to the thermodynamic theory of Wheeler and Griffiths and also in the theories of “extended scaling”. The law of the rectilinear diameter, now under siege by theory, has not yet failed us experimentally. The lines from the past to the present are sketched in this contribution, and the modern concepts of scaling will be developed from the classical equation of state. The consequences of the scaling laws for the description of thermodynamic data of fluids in the critical region will be discussed and illustrated with experimental material. Universality of critical behaciour in fluids will be demonstrated.
Enticing online consumers: a technology acceptance perspective research-in-progress

Business-to-consumer aspect of electronic commerce (EC) is the most visible business use of the World Wide Web (WWW). A virtual store, simply stated, is “a storefront in cyberspace, a place where customers can shop from their home computers and where merchants can offer merchandise and services for a fraction of the overhead required in a physical storefront” [33]. It allows companies to offer direct sales to their customers through an electronic channel [17]. The fundamental problem motivating this research study is that in order for a virtual store to compete effectively with both physical stores and other online retailers, there is an urgent need to understand the factors that entice consumers to use a virtual store. This research aims to provide both theoretical and empirical analysis to explain consumers' use of a virtual store and its antecedents. By applying the Theory of Reasoned Action (TRA) and Technology Acceptance Model (TAM), this research takes a technology acceptance perspective to examine consumer behavior in virtual store context. The data from a survey of online consumers are used to empirically test the proposed research model. Confirmatory factor analysis (CFA) is performed to examine the reliability and validity of the measurement model, and structure equation modeling (SEM) technique is used to evaluate the causal model. The implication of the research model to both researchers and practitioners is also discussed.
Poliovirus cis-Acting Replication Element-Dependent VPg Uridylylation Lowers the Km of the Initiating Nucleoside Triphosphate for Viral RNA Replication

Initiation of RNA synthesis by RNA-dependent RNA polymerases occurs when a phosphodiester bond is formed between the first two nucleotides in the 5' terminus of product RNA. The concentration of initiating nucleoside triphosphates (NTPi) required for RNA synthesis is typically greater than the concentration of NTPs required for elongation. VPg, a small viral protein, is covalently attached to the 5' end of picornavirus negative- and positive-strand RNAs. A cis-acting replication element (CRE) within picornavirus RNAs serves as a template for the uridylylation of VPg, resulting in the synthesis of VPgpUpU(OH). Mutations within the CRE RNA structure prevent VPg uridylylation. While the tyrosine hydroxyl of VPg can prime negative-strand RNA synthesis in a CRE- and VPgpUpU(OH)-independent manner, CRE-dependent VPgpUpU(OH) synthesis is absolutely required for positive-strand RNA synthesis. As reported herein, low concentrations of UTP did not support negative-strand RNA synthesis when CRE-disrupting mutations prevented VPg uridylylation, whereas correspondingly low concentrations of CTP or GTP had no negative effects on the magnitude of CRE-independent negative-strand RNA synthesis. The experimental data indicate that CRE-dependent VPg uridylylation lowers the K(m) of UTP required for viral RNA replication and that CRE-dependent VPgpUpU(OH) synthesis was required for efficient negative-strand RNA synthesis, especially when UTP concentrations were limiting. By lowering the concentration of UTP needed for the initiation of RNA replication, CRE-dependent VPg uridylylation provides a mechanism for a more robust initiation of RNA replication.
Bioethics: comes the millenium.

Am I my Brother's Keeper?: The Ethical Frontiers of Biomedicine, Arthur L. Caplan (Indiana University Press, Bloomington, Indiana, 1998), 256 pages, $24.95. Health Care Ethics: Critical Issues for the 21st Century, John F. Monagle & David C. Thomasma, Eds. (Aspen Publishers, Inc., Gaithersburg, Maryland, 1998), 614 pages, $65.
A long-lived life history for a tropical, deepwater snapper (Pristipomoides filamentosus): bomb radiocarbon and lead-radium dating as extensions of daily increment analyses in otoliths

Growth characteristics of Pristipomoides filamentosus, a deepwater eteline snapper of major economic importance, are incomplete and inconsistent across its geographical range. Early growth rates have been validated using daily increment and length-frequency analyses, but historical estimates of adult growth rates are variable and longevity is unknown. Studies of P. filamentosus in the Hawaiian Islands have cautioned against unjustified estimates of longevity, but 18 years has at times been uncritically assumed as the maximum age. The present study addresses these age, growth, and longevity issues using lead-radium and bomb radiocarbon dating by providing valid age estimates for adult P. filamentosus. Valid length-at-age estimates ranged from approximately 10 years to more than 40 years. These data, together with robust daily increment data, were used to model a fully validated, long-lived life history for P. filamentosus. This study adds to the few existing studies supporting a view that many tropical fishes, particularly deepwater species, can be longer lived than previously surmised.
The Time of Day of Food Intake Influences Overall Intake in Humans

Circadian and diurnal rhythms affect food intake, and earlier research has suggested that meal sizes increase, whereas the after-meal intervals and satiety ratios decrease over the day. We hypothesized that the time of day of food intake would be related to total intake such that intake early in the day would tend to reduce overall intake, whereas intake later in the day would tend to increase intake over the entire day. The intakes of 375 male and 492 female free-living individuals, previously obtained via 7-d diet diaries, were reanalyzed. The total and meal intakes of food energy, the amounts of the macronutrients ingested and the density of intake occurring during five 4-h periods (0600-0959, 1000-1359, 1400-1759, 1800-2159 and 2200-0159 h) were identified and related to overall and meal intakes during the entire day. The proportion of intake in the morning was negatively correlated with overall intake (r=-0.13, P<0.01), whereas the proportion ingested late in the evening was positively correlated with overall intake (r=0.14, P<0.01). The energy densities of intake during all periods of the day were positively related to overall intake (range, r=0.13-0.23, P<0.01). The results suggest that low energy density intake during any portion of the day can reduce overall intake, that intake in the morning is particularly satiating and can reduce the total amount ingested for the day, and that intake in the late night lacks satiating value and can result in greater overall daily intake.
Dynamics of DNA Molecules in a Membrane Channel Probed by Active Control Techniques

The dynamics of single-stranded DNA in an α-Hemolysin protein pore was studied at the single-molecule level. The escape time for DNA molecules initially drawn into the pore was measured in the absence of an externally applied electric field. These measurements revealed two well-separated timescales, one of which is surprisingly long (on the order of milliseconds). We characterized the long timescale as being associated with the binding and unbinding of DNA from the pore. We have also found that a transmembrane potential as small as 20 mV strongly biased the escape of DNA from the pore. These experiments have been made possible due to the development of a feedback control system, allowing the rapid modulation of the applied force on individual DNA molecules while inside the pore.