cssi/SciSciGPT-SciSciNet huggingface dataset:
Electrostatic desalting of micro-droplets to enable novel chemical/biosensing applications

Motivation/Background: Salt-based electrolyte plays a fundamentally important role in many chemical/biochemical processes. For example, sodium is found in extracellular fluid and controls the blood pressure. Similarly, magnesium is required for optimization of polymerase-chain reaction (PCR) which is important for genome sequencing. Further, ions have recently also found broad applications in flexible and transparent electronics. Indeed, precise control of electrolyte concentration at micro-scale is essential for many lab-on-chip technologies. In this paper, we provide a novel scheme to electrostatically control the spatial distribution of ions within a miniaturized droplet. Specifically, an applied bias helps accumulate ions near the electrode-surface, thereby depleting the bulk salt concentration of a small droplet. We demonstrate that the bulk desalting of droplet may potentially enable a broad range of novel applications, namely: improvement of detection limit of biosensor necessary for early-disease detection, modulation of pH profile for isoelectric protein separation, electrostatic denaturation of DNA for sensor reusability by modification of its melting temperature.
Selective alkylation of pyrimidyl-dianions: synthesis and purification of 11C labeled thymidine for tumor visualization using positron emission tomography

Reaction of 5-bromo-2'-deoxyuridine and dihydropyran in THF gave a tetrahydropyranyl ether derivative which, after treatment with n-butyllithium, was selectively alkylated in situ by [11C]methyl iodide to give [methyl-11C]thymidine and unlabeled 2'-deoxyuridine. The labeled compound can be isolated by HPLC on a reversed phase column in 12 min. The ether derivative is stable which makes it possible to prepare 11C labeled thymidine by organic synthesis in 17-25% radiochemical yield in 30-45 min with radiopurities greater than 99%. In a synthesis with no-carrier-added, a radiochemical yield of 20% was obtained. Carrier added syntheses gave 2.4-4.7 mCi of [11C]thymidine with specific activities of 250-300 mCi/mmol.
Copyright and the protection of economic rights

Copyright creates and defines property rights in intellectual and artistic property, and assigns them to a party capable of negotiation usually the creator. Subsidiary components of the copyright law assign parts of the copyright to persons other than the creator of a work, restrict the transfer of copyright elements, and provide technical procedures for enforcement, etc. While the value of copyright to authors and artists is widely thought to be great, and it is believed essential to an efficient market in intellectual and artistic creation, this appreciation usually exceeds what the facts and theory can justify. Copyright is valuable (to the author or to society) only when certain economic conditions (a market for subsidiary uses, or high fixed cost and low variable cost of copying and a market for copies) obtain. The value of copyright is closely related to the technology of reproduction; for example, it is much more important for books pirated by offset than when letterpress printing technology forced a pirate to recompose a book in order to reprint it.
Shear‐rate‐dependence modeling of polymer melt viscosity

Steady-shear-viscosity data sets for commercial-grade acrylonitrile-butadiene-styrene terpolymer, nylon, polycarbonate, poly(methylmethacrylate), and polystyrence are fitted in terms of a generalized Cross/Carreau modeling for the shear-rate dependence. Based upon extensive data sets from the open literature as well as in-house measurements, it is shown that the shear-rate dependence can be more accurately described in terms of the Cross rather than Carreau model. Although the resulting viscosity fits based upon these two models might differ by 20% or more for the same well-characterized data set, the resulting effect upon simulating the injection-molding process is found to be much smaller since such predictions reflect a range of shear stresses (varying linearly from centerline to wall of cavity) over which the two models alternate in relative magnitude. This is demonstrated by detailed representative numerical predictions which are presented for both the filling and post-filling stages.
A whole blood assay to assess peripheral blood dendritic cell function in response to Toll-like receptor stimulation

We report a practical technique to assess peripheral blood dendritic cell (DC) maturation and function in whole blood (WB), which requires minimal blood volumes and minimizes ex vivo manipulations of clinical specimens. We determined optimal conditions for flow cytometric analysis of markers of DC maturation, including CCR7, CD25, CD80 and CD83, and of the intracellular cytokines, tumor necrosis factor-alpha (TNF-alpha) and interferon-alpha (IFN-alpha), in both myeloid (mDC) and plasmacytoid (pDC) lineages. We demonstrate concentration-dependent production of these cytokines by DC following short-term stimulation with ligands to Toll-like receptors (TLRs) 2/1, 3, 4, 7, 8 and 9. Kinetic studies revealed maximal TNF-alpha and IFN-alpha protein expression at 2 to 3 h after stimulation with certain TLR ligands. Finally, utilizing cells from a cohort of eight healthy donors, we compared DC responses to TLR activation in WB, freshly isolated peripheral blood mononuclear cells (PBMC) and cryopreserved PBMC. We found that TNF-alpha responses were essentially preserved, but IFN-alpha responses were profoundly diminished or entirely abrogated following cryopreservation. In conclusion, we propose that WB analysis of peripheral DC function is a rapid, reliable and simple method to evaluate TLR function in clinical specimens, which obviates artifact-prone cell purification. The major impact of cryopreservation on some DC responses further strengthens the case for a rapid method that uses fresh blood.
Baroreflex-mediated heart rate and vascular resistance responses 24 h after maximal exercise.

INTRODUCTION: Plasma volume, heart rate (HR) variability, and stimulus-response relationships for baroreflex control of forearm vascular resistance (FVR) and HR were studied in eight healthy men after and without performing a bout of maximal exercise to test the hypotheses that acute expansion of plasma volume is associated with 1) reduction in baroreflex-mediated HR response, and 2) altered operational range for central venous pressure (CVP). METHODS: The relationship between stimulus (DeltaCVP) and vasoconstrictive reflex response (DeltaFVR) during unloading of cardiopulmonary baroreceptors was assessed with lower-body negative pressure (LBNP, 0, -5, -10, -15, -20 mm Hg). The relationship between stimulus (Deltamean arterial pressure (MAP)) and cardiac reflex response (DeltaHR) during loading of arterial baroreceptors was assessed with steady-state infusion of phenylephrine (PE) designed to increase MAP by 15 mm Hg alone and during application of LBNP (PE+LBNP) and neck pressure (PE+LBNP+NP). Measurements of vascular volume and autonomic baroreflex responses were conducted on two different test days, each separated by at least 1 wk. On one day, baroreflex response was tested 24 h after graded cycle exercise to volitional exhaustion. On another day, measurement of baroreflex response was repeated with no exercise (control). The order of exercise and control treatments was counterbalanced. RESULTS: Baseline CVP was elevated (P = 0.04) from a control value of 10.5 +/- 0.4 to 12.3 +/- 0.4 mm Hg 24 h after exercise. Average DeltaFVR/DeltaCVP during LBNP was not different (P = 0.942) between the exercise (-1.35 +/- 0.32 pru x mm Hg-1) and control (-1.32 +/- 0.36 pru x mm Hg-1) conditions. However, maximal exercise caused a shift along the reflex response relationship to a higher CVP and lower FVR. HR baroreflex response (DeltaHR/DeltaMAP) to PE+LBNP+NP was lower (P = 0.015) after maximal exercise (-0.43 +/- 0.15 beats x min-1 x mm Hg-1) compared with the control condition (-0.83 +/- 0.14 beats x min-1 x mm Hg-1). CONCLUSION: Expansion of vascular volume after acute exercise is associated with altered operational range for CVP and reduced HR response to arterial baroreceptor stimulation.
INTERPRETATIONS OF RELIABILITY

Some probabilistic illustrations of the reliability coefficient are provided to assist in interpretation of this measure. All explanations are derived under the assumption that the joint distribution of examinee scores from two parallel tests is well approximated by a bivariate normal distribution.
Archaelogy of computers: reminiscences, 1945-1947

The period preceding the founding of ACM was dominated by the first large computer ENIAC. Its characteristics, described here, foreshadow later developments.
A Potential Elastohydrodynamic Origin of Load-Support and Coulomb-Like Friction in Lung∕Chest Wall Lubrication

BACKGROUND: During normal breathing, the mesothelial surfaces of the lung and chest wall slide relative to one another. Experimentally, the shear stresses induced by such reciprocal sliding motion are very small, consistent with hydrodynamic lubrication, and relatively insensitive to sliding velocity, similar to Coulomb-type dry friction. Here we explore the possibility that shear-induced deformation of surface roughness in such tissues could result in bidirectional load supporting behavior, in the absence of solid-solid contact, with shear stresses relatively insensitive to sliding velocity. METHOD OF APPROACH: We consider a lubrication problem with elastic blocks (including the rigid limit) over a planar surface sliding with velocity U , where the normal force is fixed (hence the channel thickness is a dependent variable). One block shape is continuous piecewise linear (V block), the other continuous piecewise smoothly quadratic (Q block). The undeformed elastic blocks are spatially symmetric; their elastic deformation is simplified by taking it to be affine, with the degree of shape asymmetry linearly increasing with shear stress. RESULTS: We find that the V block exhibits nonzero Coulomb-type starting friction in both the rigid and elastic case, and that the smooth Q block exhibits approximate Coulomb friction in the sense that the rate of change of shear force with U is unbounded as U → 0 ; shear force ∝U(1/ 2) in the rigid asymmetric case and ∝U(1/ 3) in the (symmetric when undeformed) elastic case. Shear-induced deformation of the elastic blocks results in load supporting behavior for both directions of sliding. CONCLUSIONS: This mechanism could explain load-supporting behavior of deformable surfaces that are symmetrical when undeformed, and may be the source of the weak velocity dependence of friction seen in the sliding of lubricated, but rough, surfaces of elastic media such as the visceral and parietal pleural surfaces of the lung and chest wall.
A Novel Method for Measuring Transport Rate of Liquid Water into Paper

The transport rate of liquid water, i.e., the water penetration rate, into paper is one of the important physical properties in the printing, coating, and gluing processes. However, some kinds of paper are too thin to permit the measurement of the penetration rate in the direction of the thickness accurately. Thus, a novel method for measurement of the penetration rate has been developed. The large difference in electrostatic capacitance between soaked and dry paper and that in penetration rate between filter and thin paper were utilized as the foundation for this method. The time required for penetration through the whole sheet of thin paper was calculated from the measured penetration curve on the basis of theoretical analysis. As a result of the measurements in a relative humidity range of 40 to 70% it was concluded that this method could be useful in the characterization of thin paper materials with respect to penetration.
Regulation of gap junctional intercellular communication by TCDD in HMEC and MCF-7 breast cancer cells.

Abstract Previous studies suggest that many neoplastic tissues exhibit a decrease in gap junctional intercellular communication (GJIC). Many hydrocarbons and organochlorine compounds are environmental pollutants known to be carcinogenic. The effect of an organochlorine compound, TCDD, on GJIC in human breast cell lines has not been established. In the present study, we showed that TCDD causes an inhibition in the gap junctional activity in MCF-7 (breast cancer cells). In MCF-7 cells, an increase in the phosphorylated form of gap junctional protein, connexin 43 (Cx43), and PKC α was seen in the presence of TCDD. Gap junctional plaque formation was significantly decreased in MCF-7 cells in the presence of TCDD. Immunoprecipitation studies of PKC α showed that TCDD caused a significant 40% increase in the phosphorylated Cx43 in MCF-7 cells. TCDD also modulated the translocation of PKC α from the cytosol to the membrane and caused a 2-fold increase in the PKC α activity at 50 nM TCDD in MCF-7 cells. Calphostin C, an inhibitor of PKC α, showed a significant inhibition of PKC α activity in the presence of TCDD. Furthermore, TCDD also caused a decrease in the gap junctional activity and Cx43 protein in human mammary epithelial cells (HMEC). However, we observed a shift in the Cx43 plaques towards the perinuclear membrane in the presence of TCDD by confocal microscopy and Western blot. Overall, these results conclude that TCDD decreases GJIC by phosphorylating Cx43 via PKC α signaling pathway in MCF-7 cells; however, TCDD decreases the GJIC by affecting the localization of Cx43 in HMEC. These new findings elucidate the differential mode of effect of TCDD in the downregulation of GJIC in HMEC and MCF-7 cells.
GaN based III–V nitrides by molecular beam epitaxy

GaN and its allied compounds, AlGaN and InGaN, exhibit electrical and optical properties that are well suited for applications to green/blue/UV emitters and detectors, and high temperature electronics. While vacuum deposition of III-V nitrides is not new, only recently have noteworthy results become available. This is in part due to the use of electron cyclotron resonance (ECR) and other reactive nitrogen sources and clean molecular beam epitaxy (MBE) systems. Low-temperature deposition capability, controlled and hydrogen-free environment, and in situ diagnostic capabilities afforded by MBE make this approach attractive for producing novel structures for devices and understanding the growth pathways which are distinctly different from the conventional III-V compounds. Cubic and wurtzite phases of GaN have been grown with MBE on GaAs, Si, sapphire and SiC, 3C and 6H, substrates. The p-type Mg-doped films require no post-anneaIs for activation, albeit with lower mobilities than those of organometallic chemical vapor deposition (OMCVD) films. Band edge luminescence with negligible yellow emission has been obtained. Electron mobilities are as high as about 600 cm 2 /V. s with n-type doping levels in the high 10 16 cm -3 in wurtzitic films with cubic phase exhibiting higher values
Fertility, Employment, and Child-Care Costs

A sample of labor-market and birth histories is used to estimate the effects of child-care costs on employment and fertility decisions. A reduced-form empirical analysis is performed, which is based on hazard functions for transitions among various fertility-employment states. Higher child-care costs result in a lower birth rate for nonemployed women but not for employed women. Higher child-care costs also lead to an increase in the rate of leaving employment and a reduction in the rate of entering employment. The results suggest that potential behavioral effects of child-care subsidies could be significant and should be taken into account when alternative child-care policies are being debated.
Age-related decrease in proteasome expression contributes to defective nuclear factor-κB activation during hepatic ischemia/reperfusion

Hepatic ischemia/reperfusion (I/R) leads to liver injury and dysfunction through the initiation of a biphasic inflammatory response that is regulated by the transcription factor nuclear factor kappaB (NF-kappaB). We have previously shown that there is an age-dependent difference in the injury response to hepatic I/R in mice that correlates with divergent activation of NF-kappaB such that young mice have greater NF-kappaB activation, but less injury than old mice. In this study, we investigated the mechanism by which age alters the activation of NF-kappaB in the liver during I/R. Young (4-5 weeks) and old (12-14 months) mice underwent partial hepatic I/R. Livers were obtained for RNA microarray analysis and protein expression assays. Using microarray analysis, we identified age-dependent differences in the expression of genes related to protein ubiquitinylation and the proteasome. In old mice, genes that are involved in the ubiquitin-proteasome pathway were significantly down-regulated during I/R. Consistent with these findings, expression of a critical proteasome subunit, non-adenosine triphosphatase 4 (PSMD4), was reduced in old mice. Expression of the NF-kappaB inhibitory protein, IkappaB alpha, was increased in old mice and was greatly phosphorylated and ubiquitinylated. The data provide strong evidence that the age-related defect in hepatic NF-kappaB signaling during I/R is a result of decreased expression of PSMD4, a proteasome subunit responsible for recognition and recruitment of ubiquitinylated substrates to the proteasome. It appears that decreased PSMD4 expression prevents recruitment of phosphorylated and ubiquitinylated IkappaB alpha to the proteasome, resulting in a defect in NF-kappaB activation.
Transmission spectrum of a Solc filter

Abstract This paper considers the transmission of light through a stack of alternating birefringent plates. Coupled mode theory, Jones calculus and a recently developed coherent matrix method are employed to calculate the transmission spectrum of a Solc filter. The results are compared and discussed.
Sexual segregation and its ontogeny in squirrel monkey social structure

Abstract Four groups of squirrel monkeys were observed to determine the primary basis of adult group structure. These studies included observations on (1) intact and gonadectomized males and females during and after breeding; (2) intact adults only; (3) subadults only; and, (4) a mixed group of adults and subadults. The spatial distribution of subjects in each group was used as a basic measure of social organization. It was found that for adults, regardless of hormonal status, between-sex distances were consistently greater than within-sex distances. This sexually segregated adult structure was largely attributable to the females' attaction to one another and overt rejection of the males. Subadults by themselves did not show any clear sexual segregation. However, in the presence of an adult structure, the subadults gradually manifested the segregated pattern of the adults by gravitating toward same-sex adults. These results indicate that the socialization process, rather than endogenous hormonal status, is the major determinant of adult social structure in squirrel monkeys.
Bankers' responses to the ETC Act: Attitudes and the degree of international involvement

Abstract Past research has identified several variables as determinants of the export behavior for manufacturing firms. This article studies the banking community's decision to participate in the Export Trading Company Act of 1982 by examining their attitudes and their degree of international involvement. It concludes that the banking community's intention to participate in export trading companies is indeed a function of their attitudes toward the legislation and the stage of their international involvement.
Use of ultra-high frequencies in tracking meteorological balloons

On February 1, 1935, in addressing a meeting held at the Blue Hill Meteorological Observatory in celebration of its fiftieth anniversary, Dr. Charles F. Brooks used these words: “The next major step in the exploration of the atmosphere will, therefore, be the frequent and general use of radio sounding-balloons, a relatively recent invention … Blue Hill Observatory should experiment with them to test the practicability of this method as a routine procedure.” In the following month a program of study of this problem was undertaken and this paper presents a report of progress, an outline of the problem, and suggestions for the mode of attack.
Glucosylceramide, a neutral glycosphingolipid anticoagulant cofactor, enhances the interaction of human and bovine activated protein C with negatively charged phospholipid vesicles

Abstract The effect of glucosylceramide (GlcCer) on activated protein C (APC)-phospholipid interactions was examined using fluorescence resonance energy transfer. Human APC, labeled with either fluorescein (Fl-APC) or dansyl (DEGR-APC) donor, bound to phosphatidylcholine/phosphatidylserine (PC/PS, 9:1 w/w) vesicles containing octadecylrhodamine (OR) acceptor with aK d app = 16 μg/ml, whereas Fl-APC (or DEGR-APC) bound to PC/PS/GlcCer(OR) (8:1:1) vesicles with aK d app = 3 μg/ml. This 5-fold increase in apparent affinity was not species-specific since bovine DEGR-APC also showed a similar GlcCer-dependent enhancement of binding of APC to PC/PS vesicles. From the efficiency of fluorescence resonance energy transfer, distances of closest approach of ∼63 and ∼64 A were estimated between the dansyl on DEGR-APC and rhodamine in PC/PS/GlcCer(OR) and PC/PS(OR), respectively, assuming κ2 = 2/3. DEGR-APC bound to short chain C8-GlcCer with an apparent K d of 460 nm. The presence of C8-GlcCer selectively enhanced the binding of C16,6-NBD-phosphatidylserine but not C16,6–7-nitrobenz-2-oxa-1,3-diazole (NBD)-phosphatidylcholine to coumarin-labeled APC. These data suggest that APC binds to GlcCer, that PC/PS/GlcCer vesicles like PC/PS vesicles bind to the N-terminal γ-carboxyglutamic acid domain of APC, and that one mechanism by which GlcCer enhances the activity of APC is by increasing its affinity for membrane surfaces containing negatively charged phospholipids.
Pleurobranchaea behavior: food finding and other aspects of feeding.

Investigations of Pleurobranchaea californica, a marine gastropod mollusk, have demonstrated its potential for the study of neural mechanisms underlying behavior. In this paper, we have examined certain behaviors which lay a foundation for such studies. Six experiments were performed which systematically describe aspects of the feeding behavior of this voracious carnivore. This behavior consists of several stages: arousal by food chemical stimuli, food finding, extension of the proboscis (often a very vigorous action), the grasping of food, and ingestion. The first three experiments were concerned with food finding. In contrast to earlier reports, it was found that locomotion in the presence of food chemical was not random; that reversals in direction were more frequent; and that if the chemical gradient were steep enough, animals turned in the direction of food. The remaining experiments were concerned with the location of chemical receptors, resonses to tactile stimuli, and satiation. Food-chemical stimuli elicited feeding responses when the anterior edge of the oral veil and foot, the rhinophore tips and certain other anterior areas were stimulated. Pieces of meat (squid), when used as tactile stimuli to many anterior body areas, elicited approach responses; but nonfood, tactile stimuli (in the presence of squid extract) had little effect. When animals were fed bits of food at regular intervals, satiation occurred after they ate an amount equal to 5–10% of their body weight.
LIMIT ANALYSIS FOR COMBINED EDGE AND PRESSURE LOADING ON A CYLINDRICAL SHELL

Equations describing the stress field and velocity field occurring in a circular cylindrical shell at plastic collapse are derived corresponding to stress states lying on each face of a yield surface for a uniform shell of material obeying the Tresca yield condition. They are then applied to the case of a shell under combined axisymmetric loadings (moment, shear force, and axial force) at one end and uniform internal or external pressure on the lateral surface. For a sufficiently long shell, complete solutions are obtained for a fixed far end, and for a certain range of values of axial force and pressure, they are obtained for a free far end. All the solutions are represented by either closed form or by quadratures. It is shown that in many cases the radial velocity field is proportional to the shear force.
Sulforhodamine labeling of neural circuits engaged in motor pattern generation in the in vitro turtle brainstem-cerebellum

A fluorescent molecular probe was used in combination with a novel in vitro preparation to study spatial patterns of neural activity associated with motor pattern generation. The in vitro brainstem-cerebellum preparation takes advantage of the turtle's unusual resistance to anoxia to preserve the entire neural network that connects the cerebellum, red nucleus, and reticular formation. This preparation was bathed in a 0.01% solution of sulforhodamine while it was activated unilaterally by electrical stimulation of the dorsal quadrant of the spinal cord for 1 hr. Sulforhodamine is a small, sulfonated, highly charged fluorescent molecule that is taken up by endocytosis. To examine its distribution in the cerebellum and brainstem, coronal sections were prepared and viewed under epifluorescence illumination. Distinctive spatial patterns of labeling were associated with unilateral electrical stimulation of the in vitro network, suggesting that dye uptake was activity dependent. Blockade of uptake with altered magnesium and calcium concentrations indicated that single spike discharge evoked ortho- or antidromically was insufficient to induce dye uptake. Instead, sulforhodamine staining correlated with the presence of burst discharge that was recorded extracellularly from the red nucleus. Blockade of burst discharge with excitatory amino acid receptor antagonists prevented dye uptake in the red nucleus, the lateral cerebellar nucleus, and other structures that are known to be interconnected by recurrent anatomical pathways. These results suggest that sulforhodamine is internalized by intensely active neurons. The spatial distributions of label support the hypothesis that burst discharges in the turtle red nucleus are mediated by excitatory amino acid neurotransmitters and sustained by recurrent excitation in cerebellorubral synaptic pathways. Positive feedback in these recurrent pathways may provide an important driving force for the generation of motor programs that control limb movements.
A scalable parallel algorithm for dynamic range-limited n-tuple computation in many-body molecular dynamics simulation

Recent advancements in reactive molecular dynamics (MD) simulations based on many-body interatomic potentials necessitate efficient dynamic n-tuple computation, where a set of atomic n-tuples within a given spatial range is constructed at every time step. Here, we develop a computation-pattern algebraic framework to mathematically formulate general n-tuple computation. Based on translation/reflection-invariant properties of computation patterns within this framework, we design a shift-collapse (SC) algorithm for cell-based parallel MD. Theoretical analysis quantifies the compact n-tuple search space and small communication cost of SC-MD for arbitrary n, which are reduced to those in best pair-computation approaches (e.g. eighth-shell method) for n = 2. Benchmark tests show that SC-MD outperforms our production MD code at the finest grain, with 9.7-and 5.1-fold speedups on Intel-Xeon and BlueGene/Q clusters. SC-MD also exhibits excellent strong scalability.
Ethical considerations of clinical photography in an area of emerging technology and smartphones

Recent advances in digital technology including internet, email and smartphones has revolutionised clinical photography and medical record data storage. The use of smartphones is becoming ubiquitous among medical professionals and the use of clinical photography has become an integral component of the management of patients in a variety of visually orientated specialties. Although clinical photography has its benefits, with this evolving technology also emerge new ethical, legal and social issues, which clinicians must be aware of.
Origin of the activity drop with the E50D variant of catalytic antibody 34E4 for Kemp elimination.

In enzymes, multiple structural effects cooperatively lead to the high catalytic activity, while individually these effects can be small. The design of artificial enzymes requires the understanding and ability to manipulate such subtle effects. The 34E4 catalytic antibody, catalyzing Kemp elimination of 5-nitrobenzisoxazole, and its Glu50Asp (E50D) variant are the subject of the present investigation. This removal of only a methylene group yields an approximately 30-fold reduction in the rate for the catalyzed Kemp elimination. Here, the aim is to understand this difference in the catalytic performance. The mechanism of Kemp elimination catalyzed by 34E4 and the E50D mutant is elucidated using QM/MM Monte Carlo simulations and free energy perturbation theory. In both proteins, the reaction is shown to follow a single-step, concerted mechanism. In the mutant, the activation barrier rises by 2.4 kcal/mol, which corresponds to a 62-fold rate deceleration, in good agreement with the experimental data. The positions and functionality of the residues in the active site are monitored throughout the reaction. It is concluded that the looser contact with the base, shorter base-Asn58 contact, less favorable π-stacking with Trp91 in the transition state of the reaction, and different solvation pattern all contribute to the reduction of the reaction rate in the E50D variant of 34E4.
A new error criterion for near-lossless image compression

This paper presents a new criterion for near-lossless image compression and compares it with the more familiar maximum pixel error criterion in terms of compression performance and coded image subjective quality. In this new framework we compress an image in such a way that at each pixel the total error between the original and the coded images over a W/spl times/W window around the pixel does not exceed /spl epsiv/ in magnitude. The new criterion's main advantage is that it preserves image brightness and color. The compression scheme used in this work is similar to a trellis-searched scheme proposed by Ke and Marcellin (1995) in that our scheme is also a predictive, context-based scheme. However, the search for all optimal paths, representing a set of reconstruction values for an image row that satisfies the error criterion and yields the minimum bit rate, has to be done in a planar directed graph instead of a trellis. We show that this framework is also applicable to a joint image filtering and compression scenario. We present simulation results showing the performance of the new error criterion and compare it with the maximum pixel error criterion.
Ideal-observer computation in medical imaging with use of Markov-chain Monte Carlo techniques.

The ideal observer sets an upper limit on the performance of an observer on a detection or classification task. The performance of the ideal observer can be used to optimize hardware components of imaging systems and also to determine another observer’s relative performance in comparison with the best possible observer. The ideal observer employs complete knowledge of the statistics of the imaging system, including the noise and object variability. Thus computing the ideal observer for images (large-dimensional vectors) is burdensome without severely restricting the randomness in the imaging system, e.g., assuming a flat object. We present a method for computing the ideal-observer test statistic and performance by using Markov-chain Monte Carlo techniques when we have a well-characterized imaging system, knowledge of the noise statistics, and a stochastic object model. We demonstrate the method by comparing three different parallel-hole collimator imaging systems in simulation.
Role of newly synthesized cholesterol or its metabolites on the regulation of bile acid biosynthesis after short-term biliary diversion in the rat

Cholesterol 7αhydroxylase, the rate-limiting enzyme in the bile acid biosynthetic pathway, is thought to be regulated by hydrophobic bile acids through negative feedback control. The role of cholesterol in the regulation of cholesterol 7αhydroxylase is more controversial, in part because of incomplete understanding of the relationship between the pathways of cholesterol synthesis and degradation. The main objective of this study was to define the interaction between these two pathways in an experimental model in which the supply of newly synthesized cholesterol was interrupted by sustained infusion of mevinolin (lovastatin), an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA reductase) or accelerated by a continuous infusion of mevalonate, a cholesterol precursor. The study was carried out in rats subjected to short-term bile fistula. In one set of experiments, rats were treated postoperatively with mevinolin (5 mg/kg loading dose followed by 2 mg/kg/hr infusion), mevalonate (180 μmol/hr infusion) or both for up to 96 hr. In a separate set of experiments, rats were infused intraduodenally with taurocholate (36 μmol/100 gm/hr for up to 96 hr). We determined cholesterol 7αhydroxylase- and HMG-CoA reductase specific activities at those time intervals, whereas bile acid synthesis rates were determined throughout the study. Compared with rats not subjected to surgery, rats with short-term biiary diversion had increases in cholesterol 7αhydroxylase activity of 259% and 827% at 48 and 96 hr, respectively. The increase in bile acid biosynthesis was less pronounced. Continuous infusion of mevinolin completely prevented increases in cholesterol 7α-hydroxylase specific activity and bile acid biosynthesis at both time intervals. Intraduodenal infusion of taurocholate alone also suppressed cholesterol 7α-hydroxylase activity. In contrast, infusion of mevalonate led to rapid up-regulation of cholesterol 7α-hydroxylase, with activity 526% greater than basal levels at 48 hr. We conclude that regulation of cholesterol 7α-hydroxylase is under multivalent control in volving a number of regulatory factors. Up-regulation of cholesterol 7α-hydroxylase after short-term biliary diversion occurs as a result of diversion of bile acids away from the liver and the presence of a normally functioning cholesterol biosynthetic pathway. Thus regulation of cholesterol 7α-hydroxylase appears to be under the dual control of bile acids and newly synthesized cholesterol or its metabolites. Lipoprotein cholesterol, a substrate for cholesterol 7α-hydroxylase and bile acid synthesis, does not compensate for the lack of endogenous production of cholesterol and, at least in this model, does not appear to be regulatory. (HEPATOLOGY 1993;18:660–668.)
The Role of Creative Expression in Diabetes: An Exploration Into the Meaning Making Process

In this narrative exploration of meaning making through the use of creative arts, we recorded the experiences of 8 women with type 1 diabetes. Through a conceptual framework of creative expression as a way of knowing, we designed this study to evoke affective and metaphorical connections to the meaning of diabetes. The initial narrative interview findings reflected the experience of the participants, with three primary themes emerging: experiencing negative emotions about diabetes, putting a positive "spin" on the negative as a way to make meaning, and resisting against diabetes and the medical approach. During the creative arts process, we encouraged further exploration into the meaning-making process using imagery and photographs created by the participants. Final interview findings addressed the need for moving beyond numbers, and attention to the meaning-making process in patient care.
Identification of a surface glycoprotein on African green monkey kidney cells as a receptor for hepatitis A virus.

Abstract Very little is known about the mechanism of cell entry of hepatitis A virus (HAV), and the identification of cellular receptors for this picornavirus has been elusive. Here we describe the molecular cloning of a cellular receptor for HAV using protective monoclonal antibodies raised against susceptible African green monkey kidney (AGMK) cells as probes. Monoclonal antibodies 190/4, 235/4 and 263/6, which reacted against similar epitopes, specifically protected AGMK cells against HAV infection by blocking the binding of HAV. Expression cloning and nucleotide sequence analysis of the cDNA coding for epitope 190/4 revealed a novel mucin-like class I integral membrane glycoprotein of 451 amino acids, the HAV cellular receptor 1 (HAVcr-1). Immunofluorescence analysis indicated that mouse Ltk- cells transfected with HAVcr-1 cDNA gained limited susceptibility to HAV infection, which was blocked by treatment with monoclonal antibody 190/4. Our results demonstrate that the HAVcr-1 polypeptide is an attachment receptor for HAV and strongly suggest that it is also a functional receptor which mediates HAV infection. This report constitutes the first identification of a cellular receptor for HAV.
Solubility of 2-Hydroxybenzoic Acid in Select Organic Solvents at 298.15 K

Experimental solubilities are reported for 2-hydroxybenzoic acid dissolved in 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol, 1-pentanol, 1-octanol, dibutyl ether, 1,4-dioxane, tetrahydrofuran, ethyl acetate, butyl acetate, 2-propanone, 2-butanone, and cyclohexanone at 298.15 K. Results of these measurements reveal that the observed solubilities in the eight alcohol solvents fall within a fairly narrow mole fraction range of each other. 2-Hydroxybenzoic acid is more soluble in both 1,4-dioxane and tetrahydrofuran than in any of the other alcohol, ester, or ketone solvents studied.
Antihypertensive benzopyran-related potassium channel activators: a role for lipophilicity

Abstract A series of benzopyran-related potassium channel activators were prepared and evaluated at the calculated ED 30 dose in the spontaneously hypertensive rat. The duration of the blood pressure lowering effect was found to be related to the lipophilicity of the agent and was independent of the potency.
Democracy, interrupted: Regime change and partisanship in twentieth-century Argentina

Electoral volatility is much higher in new than in advanced democracies. Some scholars contend that weak partisan ties among the electorate lie behind this high volatility. Political parties in new democracies do not invest in building strong linkages with voters, they claim; hence partisanship is not widespread, nor does it grow over time. Our view is that democratic processes do encourage the spread of partisanship and hence the stabilization of electoral outcomes over time in new democracies. But this dynamic can be masked by countervailing factors and cut short by regime instability. We expect that, all else being equal, volatility will decline over time as a new democracy matures but increase again when democracy is interrupted. We use disaggregated ecological data from Argentina over nearly a century to show that electoral stability grows during democratic periods and erodes during dictatorships.
Theory and Modeling

As a first step to the modeling of the scattering data, incoherent scattering background was subtracted by applying Porod’s law. In the scattering profiles, at sufficiently high-q values, the scattering originates solely from the interface between matrix and scattering object.
Copper Workers, Organized Labor, and Popular Protest under Military Rule in Chile, 1973–1986

In April of 1983, the Chilean copper miners' confederation (the Confeder aci?n de Trabajadores de Cobre, or CTC), representing 26,000 copper workers, called for a general strike in Chile's copper mines and for a day of national protest against the military regime of Augusto Pinochet. More than 8,000 workers in El Teniente, the world's largest underground copper mine, paralyzed production for twenty-four hours in an illegal wildcat strike while tens of thousands of workers and urban poor people (pobladores) went out in the streets to demand a return to democracy and to protest the military regime's repressive labor policies and neoliberal economic policies. The CTC declaration and the strike in the El Teniente mine placed the miners in the leadership of opposition to Pinochet and at the head of the reinvigorated national labor movement.1 In spite of the copper miners' central role in the resurgence of civilian opposition to the military regime, they have been largely ignored in the literature on the transition to democracy in Chile. While historians and social scientists have described the important role played by unions and workers in modern industrial sectors in Brazil and Argentina during the 1970s and 1980s, no corresponding analysis of Chile's industrial workers and unions under the Pinochet regime has emerged. Social scientists and historians have focused on the mobilizations of the unemployed, the poor, and members of the informal sector in movements based in working-class urban neighborhoods and shantytowns.2 Recent research has shown that urban industrial workers did organize an independent and militant union movement between 1980 and 1982 in Chile.3 Less attention has been paid to the connections between the struggles of industrial workers during these years, traditions of left-wing political militancy and labor activism that exisited before the 1973 coup that overthrew the socialist government of Salvador Allende, and the wave of popular protests that began in 1983. The case of the copper miners helps to amend the analytical distinc tion between the organization of industrial workers in factories and mines and the movements of the urban poor in a number of ways. First, the miners' continued resistance to the military dictatorship in workplace based strikes and protests betwen 1977 and 1982 demonstrates that the revival of union activity between 1980 and 1982 in Chile, at least in the mining sector, was tied to the resilience of pre-1973 forms of labor struggle and political activism in the Communist, Socialist, and Christian Democrat ic parties. Second, while a number of writers have regarded this period of
Ethnographic Determinism: Samoa and the Margaret Mead Controversy

intrinsic value in that. But the image of Freeman feeding an intellectual granary still leaves the story short. Freeman's approach to criticizing Mead has been less domestic than military. His call to battle has forced a fight over thought about Samoa and fieldwork, comparative ethnography, historical continuity and culture change, proper analytic language in ethnographic reports, anthropology's public image, and much more. Through it all, one cannot help but notice that he has made his call from a higher horizon by climbing on the back of a popular giant. In fact, it might be fair to say that Margaret Mead has once again had a hand in giving anthropology public direction, both as prop for Freeman's high view and through her continued presence as scholar, writer, friend, and mentor in the debates over her work.
BOTULINUM TOXIN URETHRAL SPHINCTER INJECTION TO RESTORE BLADDER EMPTYING IN MEN AND WOMEN WITH VOIDING DYSFUNCTION

Purpose: Botulinum toxin injection into the external urinary sphincter in spinal cord injured men with detrusor-sphincter dyssynergia has been reported. We expand the clinical use of botulinum toxin for a variety of bladder outlet obstructions and to decrease outlet resistance in patients with acontractile detrusor but who wish to void by the Valsalva maneuver.Materials and Methods: Prospective treatment was performed for voiding dysfunction in 8 men and 13 women 34 to 74 years old. The reasons for voiding dysfunction included neurogenic detrusor-sphincter dyssynergia in 12 cases, pelvic floor spasticity in 8 and acontractile detrusor in 1 patient with multiple sclerosis who wished to void by the Valsalva maneuver. Using a rigid cystoscope and a collagen injection needle, a total of 80 to 100 units of botulinum A toxin (Botox * *Allergan, Inc., Irvine, California.) were injected into the external sphincter at the 3, 6, 9 and 12 o’clock positions.Results: Preoperatively 19 of 21 patients were on indwelling...
p53 deficiency and misexpression of protein kinase CK2α collaborate in the development of thymic lymphomas in mice

Protein kinase CK2 (casein kinase II) is a serine-threonine protein kinase with many substrates, some of which are involved in cell cycle regulation. CK2 activity is elevated in human solid tumors and leukemia, and dysregulated expression of CK2 induces lymphoma in transgenic mice. Mice that are deficient in p53 also develop lymphomas, and p53 activity may be regulated by CK2 phosphorylation. Here we demonstrate that CK2alpha transgenic mice partially or completely deficient in p53 develop thymic lymphomas at a markedly accelerated rate when compared to p53-deficient mice lacking the transgene. Lymphomas originating from CK2alpha transgenic mice that are heterozygous for p53 generally lose the wild type p53 allele, indicating that loss of p53 is an important step in tumor progression. Moreover, though lymphomas occur as early as 3 weeks of age in the transgenic mice that are nullizygous for p53, they are still monoclonal, indicating that additional stochastic mutations are required for their development. These lymphomas express high levels of myc mRNA and frequently ectopically express Lmo-2, a transcription factor involved in human T cell acute lymphocytic leukemia. The p53-null CK2alpha transgenic lymphomas grow rapidly but are highly prone to apoptosis, suggesting that transformation occurs through synergistic dysregulation of cell cycle control induced by misexpression of CK2 and loss of function of p53.
Generalized Talbot-Lau Atom Interferometry

Publisher Summary This chapter describes a particular form of a grating interferometer called the generalized Talbot-Lau (GTL) interferometer. The chapter first identifies a significant weakness (low throughput) of its progenitor form, separated beam envelope (SBE) interferometry, outlines the operating principles of the GTL interferometry, and shows how GTL interferometry remedies this weakness. The GTL interferometry is based on a unique form of interference intimately associated with Fresnel diffraction that occurs when Fraunhofer diffraction orders overlap. This effect was originally discovered in the optical domain using lenses and gratings, and is called the Talbot effect. Its diffraction pattern consists of the so-called Fourier and Fresnel fringes that, surprisingly, are actually multiply “aliased” near self-images of a grating's periodic complex amplitude transmission function. The chapter introduces the Talbot effect and gives a brief historical outline of work contributing to its understanding. It also introduces the related Lau effect and the Talbot interferometer. The chapter also shows how these can be combined to create generalized lens-free Talbot-Lau interferometers, suitable for de Broglie wave interferometry.
Seismic Isolation Development in Europe

This section presents a brief account of the development and application of seismic (or base) isolation in Europe. It appears that the first documented attempts to mitigate seismic hazard by seismic isolation were made in Europe.
Gastroesophageal Reflux Disease

Few topics in pediatric surgery spark more disagreement and foster more misunderstandings about pathophysiology and management than gastroesophageal reflux disease. The picture is confounded by the differences between small children and adults, the vastly higher energy (and volume) requirements of babies, the preponderance of non-acid reflux, the poorly defined accuracy of the diagnostic tests for reflux, the questionable effectiveness of “anti-reflux” medications, and the variations of technique and experience of surgeons. Further, there are sometimes troubling complications that can occur after anti-reflux surgery, often made worse by feckless attempts to manage the postoperative patients without regard for the mechanical constraints fundoplasty imposes on the performance and regulation of the gastrointestinal tract. It is important to consider GERD as a mechanical disease and ­surgical treatment of reflux as a way to provide a specific mechanical solution, and to take into account the biomechanics of reflux and its amelioration.