cssi/SciSciGPT-SciSciNet huggingface dataset:
Developments in amino acid analysis using capillary electrophoresis

The current status in the analysis of amino acids using capillary electrophoresis is addressed. This area of biological analysis has received increased attention with more than 200 articles being published in the last five years. This review discusses pre-, post-, and on-column derivatization techniques used to tag amino acids providing a detectable moiety. Several separation methodologies which provided resolution for large sets of amino acids are presented. An overview of advances in the enantiomeric resolution methodologies for amino acids is given. Both direct and indirect enantiomeric separation schemes are summarized. Recent advances in detection strategies for both derivatized and underivatized amino acids are presented. Applications utilizing amino acid analysis by capillary electrophoresis are described. This review covers articles published between 1991 and 1996.
WHITE BLOOD CELL (WBC) COUNT AND ERYTHROCYTE SEDIMENTATION RATE (ESR) IN SICKLE HEMOGLOBINOPATHIES: COMPARATIVE VALUES DURING STEADY STATE, BACTERIAL INFECTION, AND VASO-CCCLUSIVE CRISIS

Total and differential WBC counts were determined during the steady state (periods free of infections or crises) in 88 children with sickle hemoglobinopathies. In 22 children with SC disease and 8 with S-thalassemia these values were similar to normal children. In 58 children with SS disease the WBC count was elevated, just as in other children with asplenia and hemolysis. During vaso-occlusive crises the total WBC count and absolute level of segmented neutrophils were further elevated. In documented bacterial infections, however, the elevated total WBC counts were associated with increased levels of both segmented and band neutrophils. The mean uncorrected ESR in children with SS disease was 13 mm/hr during the steady state (33 pts), 12 mm/hr during vaso-occlusive crises (12 pts), and 39 mm/hr in documented bacterial infections (3 pts). Contrary to current concepts, these data suggest that simple tests such as the total and differential WBC count and ESR may be useful in distinguishing vaso-occlusive sickle cell crisis from bacterial infection.
A direct proof that zero degree homogeneity, monotonicity, and quasiconvexity of the indirect utility function implies negative semidefiniteness of the slutsky substitution matrix

Abstract In this paper, negative semidefiniteness of the Slutsky substitution matrix of a system of utility-maximizing consumer demand functions is proved directly from the properties of zero homogeneity, monotonicity and quasiconvexity of the indirect utility function and Roy's identity.
Subjective feelings and vascular responses in reaction to reduced control over aversiveness.

Summary.-Subjects were exposed to an aversive, modified Sidman avoidance procedure. One group had relative control over the aversiveness in that they could exercise an option for unlimited rest periods, and they could avoid electric shock by an appropriately fast response rate on a monitoring task The second group was yoked to subjects in Group I both with respect to rests and shocks, thereby producing decreased capability of behavioral control. The effects of this manipulation were evaluated by three types of dependent measures: vascular arousal (systolic and diastolic blood pressure), verbal reports of subjective feelings, and performance on a subsequent problem-solving task. The findings suggested motivational deficits along wich reduced vascular arousal among the ~oked subjects, a partern of results which may clarify some of the alternative hypotheses pertinent to "learned helplessness." A number of experimental smdies have reported performance decrements following exposure to periods of inescapable aversiveness for both animal and human subjects. Deficits in initiation of response (Seligman & Maier, 1967), persistence of response (Braud, Wepman, & Russo, 1969), cognitions related to problem solutions (Glass & Singer, 1972; Hiroto & Seligman, 1974), and sensitivity to feedback (Miller & Seligman, 1973) suggest a pervasive phenomenon. Observed parallels between these laboratory-induced effects and those found in a variecy of societal and personal ills, e.g., depression, psychosomatics, insticutionalization, also suggest a phenomenon of some social import (Miller, 1975; Seligman, 1975). While the laboratory effect appears to be reasonably reliable, with some exceptions (e.g., Roth & Bootzin, 1974; Hiroto & Seligman, 1974), a degree of controversy surrounds the conceptualization of processes involved in producing the performance decrements. At least three hypotheses seem to apply. The Seligman (1975) view suggests a threefold reaction to the inescapable procedures: cognitive, proactive interference in learning response-outcome relationships; tendencies not to initiate new behaviors; and affective responses similar to depression. This "learned helplessness" phenomenon appears to have received most attention in the literature. Another view considers he decrements to be associated with unusual patterns of arousal produced by the inescapable situation, which in turn directly interfere wich subsequent performance. This physiological view has been put forth from a variety of orientations, including observations
Refining the indications for arteriography in penetrating extremity trauma: a prospective analysis.

Abstract Purpose: Five hundred fourteen consecutive patients with an isolated upper or lower extremity penetrating injury were entered into a prospective study designed to refine the indications for diagnostic arteriography. Methods: Twenty-two (4%) patients with limb-threatening ischemia who required immediate operation and 23 (4%) who refused arteriography were excluded from subsequent analyses. The remaining 469 patients were classified as being at high, intermediate, or low risk for an arterial injury. Results: Two hundred thirteen patients who were at low risk were observed for 24 hours, discharged, and monitored as outpatients. No delayed complications of an arterial injury developed in any patient in this group. The intermediate-risk group of 151 patients and the high-risk group of 105 patients underwent arteriography. Seventy-seven injuries were identified; 24 were major (limb-threatening) and 53 were minor. Fourteen major injuries required operative repair or transcatheter embolization; the remaining 10 nonocclusive major injuries were observed without sequelae. Conclusions: By step-down logistic regression only pulse deficit (p ASC S URG 1993;17:116-24.)
Geometric optimization of a neutron detector based on a lithium glass–polymer composite

Abstract We report on the simulation and optimization of a neutron detector based on a glass–polymer composite that achieves high gamma rejection. Lithium glass is embedded in polyvinyltoluene in three geometric forms: disks, rods, and spheres. Optimal shape, geometric configuration, and size of the lithium glass fragments are determined using Geant4 simulations. All geometrical configurations maintain an approximate 7% glass to polymer mass ratio. Results indicate a 125-mm diameter as the optimal detector size for initial prototype design achieving a 10% efficiency for the thermalization of incident fission neutrons from 252 Cf. The geometrical features of a composite detector are shown to have little effect on the intrinsic neutron efficiency, but a significant effect on the gamma rejection is observed. The sphere geometry showed the best overall performance with an intrinsic neutron efficiency of approximately 6% with a gamma rejection better than 10 −7 for 280-μm diameter spheres. These promising results provide a motivation for prototype composite detector development based on the simulated designs.
Carbon Nanotube Uptake Changes the Biomechanical Properties of Human Lung Epithelial Cells in a Time-dependent Manner.

The toxicity of engineered nanomaterials in biological systems depends on both the nanomaterial's properties and the exposure duration. Herein we used a multi-tier strategy to investigate the relationship between user-characterized multi-walled carbon nanotubes (MWCNTs) exposure duration and their induced biochemical and biomechanical effects on model human lung epithelial cells (BEAS-2B). Our results showed that exposure to MWCNTs leads to time-dependent intracellular uptake and generation of reactive oxygen species (ROS), along with time-dependent gradual changes in cellular biomechanical properties. In particular, the amount of internalized MWCNTs followed a sigmoidal curve with the majority of the MWCNTs being internalized within 6 h of exposure; further, the sigmoidal uptake correlated with the changes in the oxidative levels and cellular biomechanical properties respectively. Our study provides new insights into the time-dependent induced toxicity caused by exposure to occupationally relevant doses of MWCNTs and could potentially help establish bases for early risk assessments of other nanomaterials' toxicological profiles.
Classical conditioning of the rabbit’s nictitating membrane response to a pneumatically driven vibrotactile CS

The present paper reports the development of a pneumatically driven, noiseless, vibrotactile transducer. In addition, an illustrative set of conditioning data were presented that revealed the ability of the transducer to generate an effective vibrotactile CS that was unconfounded by auditory components.
USING THE SPATIAL DISTRIBUTION OF BIDDERS TO DETECT COLLUSION IN THE MARKETPLACE: EVIDENCE FROM TIMBER AUCTIONS*

This study develops identification strategies utilizing spatial bidding patterns to detect possible collusion in auction markets. The identification strategy is applied to examine bidder behavior using data drawn from nearly 3,000 auctions (over 10,000 individual bids) for cutting rights of standing timber in British Columbia for the period 1996–2000. Results suggest that observed patterns of behavior are inconsistent with a model of perfectly competitive bidding. Further, changes in such patterns across geographic space are remarkably consistent with patterns of decay in the transmission of knowledge reported in previous empirical work on spillovers.
Dynamic stress intensity factors for homogeneous and smoothly heterogeneous materials using the interaction integral method

Dynamic stress intensity factors (DSIFs) are important fracture parameters in understanding and predicting dynamic fracture behavior of a cracked body. To evaluate DSIFs for both homogeneous and non-homogeneous materials, the interaction integral (conservation integral) originally proposed to evaluate SIFs for a static homogeneous medium is extended to incorporate dynamic effects and material non-homogeneity, and is implemented in conjunction with the finite element method (FEM). The technique is implemented and verified using benchmark problems. Then, various homogeneous and non-homogeneous cracked bodies under dynamic loading are employed to investigate dynamic fracture behavior such as the variation of DSIFs for different material property profiles, the relation between initiation time and the domain size (for integral evaluation), and the contribution of each distinct term in the interaction integral.
1507 PARADOXIC HYPERTENSION (PH) IN RATS EXPOSED TO BOTH CLONIDINE (CL) AND PROPRANOLOL (P)

To assess PH seen clinically in our patients, either CL (.lmg/kg/24h) or P (200mg/kg/24h) was given in drinking water singly and then together to normal (N) or spontaneously hypertensive (SHR) rats and blood pressure followed by tail plethysmography. (Letter after Group denotes first drug given; values=Δ BP (mmHg); Subsequently SHR or N rats on oral CL or P were anesthetized with pentobarbital and given graded infusions of P or CL while BP responses to low-dose drug (CL 6 ug/kg or P .075mg/kg); for 5 minutes BP rose 2-10 mmHg (p < 0.02) prior to sustained fall of 5-15mmHg. Graded doses of Phentolamine did not influence response. We have shown that PH seen in patients can be produced in both N and SHR rats. We conclude that PH is probably not due to increased alpha stimulation (from CL) in the presence of betablockade with P.
Deuterium content of natural waters and other substances

Abstract A mass spectrometric method for the accurate determination of the hydrogen-deuterium ratio has been developed. It is possible to determine this ratio to ± 0.10% using material of “normal abundance”, i.e., 1 part D in 6700 parts H. Samples as small as 0.1 mg H2 (0.001 ml H2O) can be run. Natural evaporation and condensation that have been shown to fractionate the oxygen isotopes also fractionate the hydrogen isotopes. The ratio of these two fractionations is equal to the ratio between the ratios of the vapour pressures of H 2 O HDO and of H 2 O 16 H 2 O 18 . Ocean waters range from 0.0153 to 0.0156 mole % deuterium, whereas fresh waters of the United States range from 0.0133 to 0.0154 mole % deuterium. A measurement of Yellowstone Park fumarole gases gives a minimum temperature of 400° for the equilibrium H2O + HD = HDO + H2 in the gases.
The American National Election Studies: A Progress Report

covering all thirteen presidential elections, and 10 midterm elections, since 1948, a crucial turning point came in 1977 when NSF established NES as the first national social science resource, a model NSF later used with the General Social Survey and the Panel Study of Income Dynamics. Prior to this time, the leaders of the Michigan election studies, the predecessors of NES, sought funding independently for each election study. Although team leaders, including especially Warren E. Miller, placed great value on developing the time series, sought to explore the frontiers of research on electoral politics and public opinion, and understood the significance of these studies for the broader re-
Choosing among confusably distributed stimuli with specified likelihood ratios.

A study of choice behavior for overlapping normally distributed stimuli, with specified distribution locations, separations, dispersions, and likelihood ratios was carried out. A distributed stimulus consisted of a set of dots sampled from a bivariate normal distribution and placed on separate cards. Cards with dots from two or three distributions were mixed together and shown one by one to S, who had to choose from which distribution each dot derived, and give a confidence rating. Two theoretical choice models succeeded in bracketing the results: (a) statistical decision theory and (b) a probability micromatching (Mμ) model. Mμ states that choices are made probabilistically and in the proportion defined by the likelihood ratio. Confidence was not always monotonic with likelihood. The perceived distance between distribution centers was about twice the true distance.
Cardiac deformation recovery via incompressible transformation decomposition

This paper presents a method for automated deformation recovery of the left and right ventricular wall from a time sequence of anatomical images of the heart. The deformation is recovered within the heart wall, i.e. it is not limited only to the epicardium and endocardium. Most of the suggested methods either ignore or approximately model incompressibility of the heart wall. This physical property of the cardiac muscle is mathematically guaranteed to be satisfied by the proposed method. A scheme for decomposition of a complex incompressible geometric transformation into simpler components and its application to cardiac deformation recovery is presented. A general case as well as an application specific solution is discussed. Furthermore, the manipulation of the constructed incompressible transformations, including the computation of the inverse transformation, is computationally inexpensive. The presented method is mathematically guaranteed to generate incompressible transformations which are experimentally shown to be a very good approximation of actual cardiac deformations. The transformation representation has a relatively small number of parameters which leads to a fast deformation recovery. The approach was tested on six sequences of two-dimensional short-axis cardiac MR images. The cardiac deformation was recovered with an average error of 1.1 pixel. The method is directly extendable to three dimensions and to the entire heart.
GENDER-LINKED STEREOTYPES AND MOTIVATION AFFECT PERFORMANCE IN THE PRISONER'S DILEMMA GAME

40 men and 40 women played a Prisoner's Dilemma Game against a simulated partner for 30 trials. The task simulated corporate managerial decisions with a profit motive, and higher profits were obtained when subjects made noncooperative choices. All subjects received the same preprogrammed sequence of “partner” responses, and half played against a female, half against a male “partner.” The female “partner” received significantly more cooperative responses than the male. Trial blocks and the interaction of “partner's” gender with trial blocks were significant effects, and motivation played a significant interactive role that modulated subject's game behavior. Self-fulfilling confirmatory hypothesis testing appeared to be operative in the display of gender-linked stereotypes.
JavaPDG: A New Platform for Program Dependence Analysis

Dependence analysis is a fundamental technique for program understanding and is widely used in software testing and debugging. However, there are a limited number of analysis tools available despite a wide range of research work in this field. In this paper, we present JavaPDG1, a static analyzer for Java bytecode, which is capable of producing various graphical representations such as the system dependence graph, procedure dependence graph, control flow graph and call graph. As a program-dependence-graph based analyzer, JavaPDG performs both intra- and inter-procedural dependence analysis, and enables researchers to apply a wide range of program analysis techniques that rely on dependence analysis. JavaPDG provides a graphical viewer to browse and analyze the various graphs and a convenient JSON based serialization format.
Impact of phosphorus removal at the Danbury, Connecticut sewage treatment plant on water quality in Lake Lillinonah

Lake Lillinonah is a highly eutrophic impoundment on the Housatonic River receiving 20 to 30% of its P load from domestic wastewaters from Danbury, Connecticut. In 1977 P removal from the domestic wastewater treatment plant was initiated, reducing the P load from the Danbury sewage treatment plant from 13700 to 6700 kg yr−1 in 1976 and 1977, respectively. The flows of the Housatonic River in 1976 and 1977 were also dissimilar; in 1977 about twice as much water entered Lake Lillinonah as in the former year.
Aldehyde dehydrogenase activity as the basis for the relative insensitivity of murine pluripotent hematopoietic stem cells to oxazaphosphorines

Abstract The ex vivo sensitivity of murine pluripotent hematopoietic stem cells (CFU-S) and myeloid progenitor cells (CFU-GM) to 4-hydroperoxycyclophosphamide, ASTA Z 7557, phosphoramide mustard, acrolein, melphalan, and cis-platinum was determined in the absence and presence of known (disulfiram, diethyldithiocarbamate, cyanamide) or suspected [ethylphenyl(2-formylethyl)phosphinate] inhibitors of aldehyde dehydrogenase activity. As compared to CFU-GM, CFU-S were less sensitive to the oxazaphosphorine agents, 4-hydroperoxycyclophamide and ASTA Z 7557. The two cell populations were approximately equisensitive to acrolein as well as to the non-oxazaphosphorine cross-linking agents, phospharamide mustard, melphalan and cis-platinum. All four inhibitors pf aldehyde dehydrogenase activity potentiated the cytotoxic action of the oxazaphosphorines toward CFU-S; they did not potentiate the cytotoxic action of acrolein or the non-oxazaphosphorines toward these cells. The inhibitors did not potentiate the cytotoxic action of the oxazaphosphorines, non-oxazaphosphorines, or acrolein toward CFU-GM. Pyridoxal, a substrate for aldehyde oxidase, did not potentiate the cytotoxic action of oxazaphosphorines toward CFU-S. Cellular NAD-linked aldehyde dehydrogenase are known to catalyze the oxidation of the major transport form of cyclophosphamide, 4-hydroxycyclophosphamide/aldophosphamide, to an inactive metabolite, carboxyphosphamide. Our observations suggest that (1) aldehyde dehydrogenase activity is an important determinant of the sensitivity of a cell population to the oxazaphosphorines, (2) CFU-GM lack the relevant aldehyde dehydrogenase activity, and (3) the phenotypic basis for the relative insensitivity of CFU-S to oxazaphosphorines is the aldehyde dehydrogenase activity contained by these cells.
Characterization and metabolism of free fatty alcohols fromEscherichia coli

Free fatty acohols have been established as lipid components ofE. coli K-12. Using combined gas liquid chromatography-mass spectrometry, the major alcohols in aerobically grown cells were identified as 1-tetradecanol (18%), 1-hexadecanol (28%), 1-octadecanol (14%), and 2-pentadecanol (27%). Small amounts of 1-hexadecenol (3%), 2-tridecanol (8%), and 2-tetradecanol (1.5%) were also detected. Analysis of anaerobically grown cells has shown a selective decrease of the secondary alcohols. 2-Pentadecanol was present as only 7% of the total alcohol fraction, and only traces of 2-tridecanol and 2-tetradecanol were found. The major alcohols in anaerobic cells were 1-tetradecanol, 1-pentadecanol, 1-hexadecenol and 1-hexadecanol. The above observations strongly suggest two pathways for the synthesis of fatty alcohols inE. coli. One pathway synthesizes the primary alcohols and does not require molecular oxygen, and a separate pathway synthesizes the secondary alcohols and has a requirement for molecular oxygen.
Expression of the serine rich Entamoeba histolytica protein (SREHP) in the avirulent vaccine strain Salmonella typhi TY2 χ4297 (Δcya Δcrp Δasd): safety and immunogenicity in mice

Abstract Infection by the intestinal protozoan parasite Entamoeba histolytica remains a significant threat to health in much of the world. Here we describe the successful expression of the serine rich Entamoeba histolytica protein (SREHP), a protective antigen of ameba, in an attenuated vaccine strain Salmonella typhi TY2 χ 4297 ( Δcya Δcrp Δasd ). The attenuation of S. typhi TY2 χ 4297 was not altered by expression of the SREHP-maltose binding protein (MBP) fusion protein and mice parenterally vaccinated with S. typhi TY2 χ 4297 expressing SREHP-MBP developed serum anti-amebic and anti-LPS antibodies. S. typhi TY2 χ 4297 expressing SREHP-MBP represents a prototype combination vaccine designed to prevent both amebiasis and typhoid fever.
Methyl transfer from Fe (and Mo) to Sn: formation of (η5-C5H5)M(CO)nSntBu2Me (M = Fe, n = 2; M = Mo, n = 3) complexes from photochemical irradiation of (η5-C5H5)M(CO)nMe and tBu2SnH2

Formation of an Sn–CH3 bond, concomitantly with an Sn–M (M = Fe, Mo), is readily achieved from the photochemical reactions of tBu2SnH2 with (η5-C5H5)M(CO)nMe (M = Fe, n = 2; M = Mo, n = 3) via the intermediacy of (η5-C5H5)M(CO)nSntBu2H.
Combustion characteristics of water-in-oil emulsion droplets

Abstract Various combustion modes of water-in-oil emulsion droplets are postulated based on the relative volatilities and concentrations of water and oil, the intensity of internal circulation, and the fact that water and oil do not mix. It is shown that the existence of internal circulation generally inhibits microexplosion, and that increasing the system pressure enhances the occurrence of microexplosion even allowing for the longer period of droplet heating at higher pressures. Other predicted phenomena of interest include droplet temperature being limited by the lower of the boiling points of water and oil, the formation of water residues and subsequently termination of combustion upon complete depletion of oil from the droplet, and the independence of the instantaneous combustion rate on the extent of water emulsification. Experimental results obtained on single droplet combustion with minimal and extensive internal circulation generally agree with the qualitative nature of the postulated combustion modes.
Seizures and 'disappearing' brain lesions.

Background—Patients with seizures may have abnormal brain imaging. Lesions demonstrated on computerized tomography or magnetic resonance imaging often suggest the underlying cause of the seizures, and may prompt an invasive investigation for diagnosis and treatment. In an increasingly recognized subset of patients however, the imaged lesions spontaneously resolve. While poorly understood, these ‘disappearing' lesions may in fact be the consequence of seizures, rather than the cause. Two patients with ‘disappearing' lesions are presented: the first patient had a proven cause, the second a probable one. Case 1. A patient with new onset seizures had an abnormal MRI. An angiogram confirmed thrombosis of the straight sinus. On follow-up, she was doing well; repeat imaging was normal with resolution of the lesion. Case 2. A patient with a long seizure history had been well controlled on medications, and had no change in frequency of her seizures. She was found to have a left homonymous hemianopsia. MRI revealed a right parieto-occipital lesion. The patient refused further work-up and was lost to follow-up. She returned almost a year later; repeat imaging was normal. Conclusion—Patients with seizures and abnormal imaging suggestive of structural lesions may occasionally have lesions that resolve spontaneously. While some diagnoses remain elusive, an important consideration to exclude in these patients is venous thrombosis.
Evaluation of brachytherapy lung implant dose distributions from photon-emitting sources due to tissue heterogeneities.

Purpose: Photon-emitting brachytherapy sources are used for permanent implantation to treat lung cancer. However, the current brachytherapy dose calculation formalism assumes a homogeneous water medium without considering the influence of radiation scatter or tissue heterogeneities. The purpose of this study was to determine the dosimetric effects of tissue heterogeneities for permanent lung brachytherapy. Methods: The MCNP5 v1.40 radiation transport code was used for Monte Carlo (MC) simulations. Point sources with energies of 0.02, 0.03, 0.05, 0.1, 0.2, and 0.4 MeV were simulated to cover the range of pertinent brachytherapy energies and to glean dosimetric trends independent of specific radionuclide emissions. Source positions from postimplant CT scans of five patient implants were used for source coordinates, with dose normalized to 200 Gy at the center of each implant. With the presence of fibrosis (around the implant), cortical bone, lung, and healthy tissues, dose distributions and {sub PTV}DVH were calculated using the MCNP *FMESH4 tally and the NIST mass-energy absorption coefficients. This process was repeated upon replacing all tissues with water. For all photon energies, 10{sup 9} histories were simulated to achieve statistical errors (k = 1) typically of 1%. Results: The mean PTV doses calculated using tissue heterogeneities for all fivemore » patients changed (compared to dose to water) by only a few percent over the examined photon energy range, as did PTV dose at the implant center. The {sub PTV}V{sub 100} values were 81.2%, 90.0% (as normalized), 94.3%, 93.9%, 92.7%, and 92.2% for 0.02, 0.03, 0.05, 0.1, 0.2, and 0.4 MeV source photons, respectively. Relative to water, the maximum bone doses were higher by factors of 3.7, 5.1, 5.2, 2.4, 1.2, and 1.0 The maximum lung doses were about 0.98, 0.94, 0.91, 0.94, 0.97, and 0.99. Relative to water, the maximum healthy tissue doses at the mediastinal position were higher by factors of 9.8, 2.2, 1.3, 1.1, 1.1, and 1.1. However, the maximum doses to these healthy tissues were only 3.1, 7.2, 11.3, 10.9, 9.0, and 8.1 Gy while maximum bone doses were 66, 177, 236, 106, 49, and 39 Gy, respectively. Similarly, maximum lung doses were 55, 66, 73, 74, 73, and 73 Gy, respectively. Conclusions: The current brachytherapy dose calculation formalism overestimates PTV dose and significantly underestimates doses to bone and healthy tissue. Further investigation using specific brachytherapy source models and patient-based CT datasets as MC input may indicate whether the observed trends can be generalized for low-energy lung brachytherapy dosimetry.« less
Evidence for a sequestration of function within the area postrema based on scanning electron microscopy and the penetration of horseradish peroxidase.

Scanning electron microscopy and the penetration of horseradish peroxidase, especially from the ventricular surface, has been utilized to determine the distinctive properties of the posterior portion of the area postrema. This part of the organ is characterized by a non-ciliated surface composed of flattened cells, which appear less permeable to cisternally injected peroxidase than the ciliated ependymal cells covering the anterior part of the area postrema. However, more diffuse and rapid penetration of peroxidase into the posterior region is achieved by way of the perivascular spaces which appear in direct communication with the CSF. No such filling is noted in the anterior area postrema. The posterior portion also contains cells which appear to be rapidly penetrated by horseradish peroxidase and which may be important as a sensing mechanism. The chief distinction of the anterior part of the area postrema appears to be the presence of vascular connections with the choroid plexus.
An ideal column algorithm for integer programs with special ordered sets of variables

One of the most frequently occurring integer programming structures is the one which has special ordered sets of variables included in multiple choice constraints. For problems with this structure a set of ideal columns are defined from the linear programming relaxation of the integer program and a reduced integer program is formed by keeping only those columns within a specified distance from the ideal column. Conditions are established which guarantee when the optimal solution to the reduced problem is als optimal for the original problem. When these conditions are not satisfied, bounds on the optimal solution value are provided. Ideal columns are also used to establish weights for the special ordered set variables. This procedure has been implemented through a control program written by the authors for MPSX/370-MIP/370. Computational results are given.
Properties of membrane stationary states. 2. The isobaric isothermal ensemble

A multi-state membrane transport system serves as the basic model for a comparison of equilibrium and stationary state distributions of ions within an ensemble of membrane channels. Transition probabilities for intramembrane transitions are developed for consistency with an equilibrium Donnan potential and the magnitude of the flux in the stationary state can be controlled with either the bath concentrations or an externally applied potential. The stationary state distribution and operational thermodynamic parameters for the stationary state are expressed as functions of the ratio (jnet/p) where jnet is the observable net membrane flux and p is a characteristic decay constant for the intramolecular transitions. Both parameters are experimentally accessible so that their time independent ratio serves as an experimental measure of the membrane configuration. When operational thermodynamic parameters are expressed as functions of the ratio (j/p) for systems which obey the condition of detailed balance, the free energy varies quadratically with the ratio while the enthalpy, expressed as an average membrane potential, varies linearly with the ratio. As the system is driven from its equilibrium configuration by the net membrane flux the free energy increases relative to the enthalpy of the membrane. The free energy is localized in the membrane region at the expense of dissipation in the bathing solutions.
Trifluoroethanol Promotes Helix Formation by Destabilizing Backbone Exposure: Desolvation Rather than Native Hydrogen Bonding Defines the Kinetic Pathway of Dimeric Coiled Coil Folding†

We measure the effects of low concentrations of helix-stabilizing cosolvents, including 2,2,2-trifluoroethanol (TFE), on the thermodynamics and kinetics of folding of the dimeric alpha-helical coiled coil derived from the leucine zipper region of bZIP transcriptional activator GCN4. The change in kinetic behavior upon addition of 5% (v/v) TFE indicates that it stabilizes the transition state to the same degree as the fully helical native state. However, folding rates are largely insensitive to alanine to glycine mutagenesis, indicating that the majority of helical structure is formed after the transition state. Equilibrium hydrogen isotope partitioning measurements indicate that intramolecular hydrogen bonds are not strengthened by TFE and that amide hydrogen bonds in the transition state are nearly the same strength as those in the unfolded state. Thus, the mechanism by which TFE exerts its helix-stabilizing effects can be divorced from helix formation and does not depend on the strengthening of intrahelical hydrogen bonds. Rather, TFE increases the structure of the binary alcohol/water solvent, thereby increasing the energetic cost associated with solvation of the polypeptide backbone. At low concentrations, TFE destabilizes the unfolded species and thereby indirectly enhances the kinetics and thermodynamics of folding of the coiled coil. A high degree of polypeptide backbone desolvation, and not the formation of regular helical structure and native strength hydrogen bonds, is the critical feature of the transition state for folding of this small dimeric protein.
Long range forces in quantum gravity.

We calculate the leading quantum and semi-classical corrections to the Newtonian potential energy of two widely separated static masses. In this largedistance, static limit, the quantum behaviour of the sources does not contribute to the quantum corrections of the potential. These arise exclusively from the propagation of massless degrees of freedom. Our one-loop result is based on Modanese’s formulation and is in disagreement with Donoghue’s recent calculation. Also, we compare and contrast the structural similarities of our approach to scattering at ultra-high energy and large impact parameter. We connect our approach to results from string perturbation theory.
Relationship between membrane potential and electrolyte uptake by ion‐exchange membranes

Electrical potentials arising across three cation-selective membranes of low water content when they separate solutions of different concentration of the same NaCl electrolyte have been measured at 25°C. Also, electrolyte uptake by these membranes when they are in equilibrium with different solutions of NaCl has been estimated. These data together with the apparent membrane transport number derived from membrane potential have been used to check a simple relation given by Lakshminarayanaih.
Increased use-dependent plasticity in chronic insomnia.

STUDY OBJECTIVES During normal sleep several neuroplasticity changes occur, some of which are considered to be fundamental to strengthen memories. Given the evidence linking sleep to neuroplasticity, it is conceivable that individuals with chronic sleep disruption, such as patients with chronic insomnia (CI), would experience abnormalities in neuroplastic processes during daytime. Protocols testing use-dependent plasticity (UDP), one of the mechanisms underlying formation of motor memories traces, provide a sensitive measure to assess neuroplasticity in the context of motor training. DESIGN AND PARTICIPANTS A well-established transcranial magnetic stimulation (TMS) paradigm was used to evaluate the ability of patients with CI and age-matched good sleeper controls to undergo UDP. We also investigated the effect of insomnia on intracortical motor excitability measures reflecting GABAergic and glutamatergic mechanisms. SETTING Human Brain Physiology Laboratory, Johns Hopkins Medical Institutions. MEASUREMENTS AND RESULTS We found that patients with CI experienced increased UDP changes relative to controls. This effect was not due to differences in motor training. In addition, patients with CI showed enhanced intracortical facilitation relative to controls, in the absence of changes in intracortical inhibitory measures. CONCLUSION This study provides the first evidence that patients with chronic insomnia have an increased plasticity response to physical exercise, possibly due to larger activation of glutamatergic mechanisms. This suggests a heightened state of neuroplasticity, which may reflect a form of maladaptive plasticity, similar to what has been described in dystonia patients and chronic phantom pain after amputation. These results could lead to development of novel treatments for chronic insomnia.
Noradrenergic potentiation of cerebellar Purkinje cell responses to GABA: cyclic AMP as intracellular intermediary

Abstract Norepinephrine and the β-adrenergic receptor agonist, isoproterenol, have been shown to potentiate the amplitude of GABA A receptor-mediated whole-cell current responses in Purkinje cells acutely dissociated from the rat cerebellum. However, the steps leading from the activation of β-adrenergic receptors to the modulation of GABA A receptor remain to be delineated. This study tested the hypothesis that a sequelae of intracellular intermediaries involving the cyclic AMP second messenger system serves as the subcellular link to promote this heteroreceptor interaction. Exposure to cholera toxin, but not to pertussis toxin, increased the amplitude of GABA-activated current responses in acutely dissociated Purkinje cells. Intracellular dialysis with guanosine 5′- O -(3-thiotriphosphate) also resulted in a time- and dose-dependent augmentation of the response to GABA, while guanosine 5′- O -(2-thiodiphosphate) blocked the norepinephrine-mediated facilitation. A positive modulation of the current response to GABA was observed following intracellular delivery of cyclic AMP or the catalytic subunit of the cyclic AMP-dependent protein kinase. Furthermore, the norepinephrine-induced potentiation of the GABA-activated current response was prevented in the presence of the Rp isomer of cyclic AMP, the regulatory subunit of cyclic AMP-dependent protein kinase and an inhibitor of cyclic AMP-dependent protein kinase. These findings led to the formulation of a working model in which activation of the β-adrenergic receptor triggers a G s -protein-mediated transduction cascade in cerebellar Purkinje cells which activates adenylate cyclase, resulting in a rise in intracellular levels of cyclic AMP, increased phosphorylating activity by cyclic AMP-dependent protein kinase and, ultimately, a potentiation of GABA A receptor function.
The Domestic Background of Troilus and Criseyde

MY intent in the following notes is to offer certain materials which may now and again help the reader of Troilus and Criseyde to visualize the settings of the poem more nearly as Chaucer's contemporaries did. I must confess at the outset that I cannot solve numbers of problems, including the prime crux of settingthe location of various rooms in Pandarus' house and particularly the location and nature of the trap door through which Pandarus introduces Troilus into Criseyde's closet on the night of the "smoky reyn" but I hope that I can shed some light upon aspects of the scenes in which these difficulties appear that will make them a trifle easier to comprehend. I assume that to Chaucer the palaces of Criseyde, Deiphebus, Troilus, and Pandarus were mansions of his own fourteenth-century London and that when he wrote of each he had in mind some more or less definite image. The possibility that he archaized or endeavored to introduce anything exotic will not be seriously entertained in view of his usual attitude "Ther is no newe gyse that it nas old" and in view of the audience for whom he wrote. If he had not assumed universal familiarity with his settings, he would perhaps have left less to our imagination. The accounts of domestic architecture in fourteenth-century England are perforce based chiefly on ruins of manor houses, rather than city houses, and they are also sometimes contradictory and confusing. Since London once largely burned, and since all cities, London included, have a way of growing and tearing down the old to make way for the new, we have, besides inferences from the designs of rural manors, only items from various Rolls, illuminations in manuscripts, and literary allusions, often so fleeting as to be cryptic, to help us reconstruct the form of the urban dwelling. We may, however, construct in free-hand fashion a description of a typical or at least possible London mansion of that period. The diagram overleaf will be useful as a reference.
Reasoning About Grasping From Task Descriptions

The advent of multiple degree of freedom, dextrous robot hands has made robot hand control more complicated. Besides the existing problem of finding a suitable grasping position and ap-proach orientation, it is now necessary to decide the appropriate hand shape to use for a given task. In order to deal with this additional complexity, we focus on how to represent prehensile tasks for mapping task descriptions into suitable hand shapes, positions and orientations. A generic robot hand control system GeSAM is being implemented to refine task descriptions into suitable dextrous robot hand shapes using Knowledge Craft on a TI lisp machine.
Intake of Ethanol, Sodium Chloride, Sucrose, Citric Acid, and Quinine Hydrochloride Solutions by Mice: A Genetic Analysis

Mice of the 129/J (129) and C57BL/6ByJ (B6) strains and their reciprocal F1 and F2 hybrids were offered solutions of ethanol, sucrose, citric acid, quinine hydrochloride, and NaCl in two-bottle choice tests. Consistent with earlier work, the B6 mice drank more ethanol, sucrose, citric acid, and quinine hydrochloride solution and less NaCl solution than did 129 mice. Analyses of each generation's means and distributions showed that intakes of ethanol, quinine, sucrose, and NaCl were influenced by a few genes. The mode of inheritance was additive in the case of ethanol and quinine, for sucrose the genotype of the 129 strain was recessive, and for NaCl it was dominant. Citric acid intake appeared to be influenced by many genes with small effects, with the 129 genotype dominant. Correlations of sucrose consumption with ethanol and citric acid consumption were found among mice of the F2 generation, and the genetically determined component of these correlations was stronger than the component related to environmental factors. The genetically determined correlation between sucrose and ethanol intakes is consistent with the hypothesis that the higher ethanol intake by B6 mice depends, in part, on higher hedonic attractiveness of its sweet taste component.
Plasma Fibrinogen and Its Correlates in Children from a Biracial Community: The Bogalusa Heart Study

Fibrinogen levels were measured in 5- to 17-y-old children (n = 3047; 40% black and 49% female), from a well-defined biracial community. No significant race and sex differences in fibrinogen levels were observed, but levels increased (p < 0.001) with age or sexual maturation in black females. Adjusted for age, fibrinogen concentrations were positively correlated with ponderal index (weight/height3) (0.09-0.22, p < 0.01), triceps skinfold thickness (0.10-0.23, p < 0.05), and subscapular skinfold thickness (0.13-0.24, p < 0.01) in all race-sex groups. Weak correlations were found between fibrinogen level and blood pressure and lipoprotein components for some of the race-sex groups, but these become nonsignificant or minimal after adjustment for ponderal index and skinfolds. A positive correlation (0.12-0.16, p < 0.01) was found between fibrinogen and white blood cell count for Caucasians, which still held after adjustment for ponderal index and skinfolds. In a stepwise regression, ponderal index, white blood cell count, and HDL cholesterol showed an independent association with fibrinogen.
Hydrothermal synthesis of mordenite needles from erionite

Hydrothermal transformation of erionite to mordenite needles and analcime at 300°C under a confining pressure of 30 MPa is reported here. The transformation of erionite under hydrothermal conditions has implications to diagenetic reactions in tuffs and to hydrothermal stability of zeolites in a high-level nuclear waste repository environment.
Is supernova 1987A a stripped asymptotic-branch giant in a binary system?

It is proposed that the progenitor of supernova 1987A was a previously undetected red star in orbit about a blue supergiant. The progenitor was the remnant of an asymptotic-branch giant that had lost most of its hydrogen-rich envelope to its blue companion by type C mass transfer. A detailed evolutionary model strongly supports the feasibility of this proposition. It is found that the original mass of the supernova precursor was 10-15 solar (unless a large fraction of the mass was ejected from the binary sytem), and its final mass, just before the supernova event, was 3-6 solar. The system remained bound, with a new orbital period of 3-10 yr and an eccentricity of 0.1-0.4. This picture can provide plausible qualitative explanations for several anomalies in the observational properties of this supernova.
Adult age differences in comprehension and memory for computer-displayed and printed text

Younger and older adults’ reading performance for texts presented on‐line and texts presented on a printed page were examined. The younger adults spent less time reading the texts and recalled more information from the texts than did the older adults. Age differences were not affected by the method of presenting texts. On‐line presentation of texts resulted in superior comprehension evaluation and recall for both younger and older adults. Although the participants spent more time reading texts presented on‐line than printed texts, the extra reading time did not account for the superior comprehension evaluation and memory found in the online condition. The present research does not provide any evidence that age‐related deficits in reading performance are attributable to on‐line methods of text presentation, but it does suggest that some on‐line presentation methods result in improved comprehension and memory for adults.
Anterior and posterior cruciate ligament reconstruction in the new millennium: a global perspective.

In May 2000 over 50 surgeons representing 18 different countries and 5 continents assembled in Pittsburgh, Pennsylvania, USA, for the Eighth Panther Sports Medicine Symposium. Entitled “From Robotics to Gene Therapy: Sports Medicine in the New Millennium,” the symposium focused on both current perspectives and new and emerging technologies in the field of orthopedic sports medicine. Topics covered ranged from cruciate ligament reconstruction and meniscal transplantation to future directions and outcomes measurements in orthopedic sports medicine. The symposium also offered the unique opportunity of obtaining “a global perspective” on the current approaches used around the world for various sports related injuries. Eight global panels were held to provide an international viewpoint on topics such as cruciate ligament and posterolateral corner reconstruction, the dislocated knee, osteotomies about the knee, and return to play following ACL reconstruction. For each topic, each panelist gave a 6-min presentation describing his or her practice setting and patient profile, current techniques or approaches, and clinical outcomes. A 20-min question and answer session was then held (Fig.1). Finally, the session moderator presented the panel “consensus” in which the results were summarized and tabulated. The feedback that we received in response to these panels from both conferKNEE Knee Surg, Sports Traumatol, Arthrosc (2001) 9 :330–336
Future directions in solid state lanthanide and actinide chemistry

Abstract Recent accomplishments are reviewed and current challenges in the syntheses and elucidation of the bonding and electronic structure of metals, inorganic compounds and organometallic compounds containing the rare earth and actinide elements are identified.
Coral Bleaching: Coral 'refugia' amid heating seas

The Earth is getting hotter as carbon dioxide, predominantly from the burning of fossil fuels, continues to accumulate in the atmosphere. It is widely recognized that increasing temperatures pose a threat to coral reefs, but just how large a risk are these reefs facing?