cssi/SciSciGPT-SciSciNet huggingface dataset:
6 Site-Specific Modification of Enzyme Sites

Publisher Summary The application of site-specific modification of enzymes and other proteins has become increasingly common. A wide range of chemical classes is available from which a reagent for exploring a particular enzyme can be selected or designed. Structural similarity to the natural ligand is always desirable to ensure target specificity, but the goal of the investigation must be clear to permit a rational choice of the nature of the reactive group. For studies aimed at identifying amino acid participants in active or regulatory sites, or for those aimed at evaluating the kinetic properties, equilibrium binding, spectral characteristics, or X-ray structure of a stoichiometrically modified enzyme, it is important to choose a reagent type with the potential for forming quantitatively a stable, covalent bond between enzyme and affinity label. The haloketone, fluorosulfonylbenzoyl, and haloacyl derivatives may be most appropriate for these applications because they generally yield products of enzyme nucleophiles, which can be isolated and identified within an amino acid sequence. Affinity labels of this type can be used to provide information regarding the effect of occupying the particular site on the conformation of the enzyme, on the reactivity of other sites, or on subunit interactions.
Gutta-Percha: A Case of Resource Depletion and International Rivalry

Gutta-percha, the latex of the Palaquium tree, is a natural plastic with good dielectric properties, once used to insulate submarine telegraph cables. The rapid expansion of telegraphy after 1850 led to the almost total destruction of the wild trees by natives of Malaya, Sumatra, and Borneo. By the turn of the century, the depletion of this essential but slowly renewable resource caused much concern in European and American business circles. Two sciences were brought to bear on this problem. Botanists first searched for additional wild trees, then opened plantations for future production. Meanwhile, chemists sought to substitute the latex of other trees such as natural rubber and balata. In 1933, Imperial Chemical Industries created the synthetic dielectric polyethylene. The cycle from plunder to botanical then to chemical substitutes is typical of the use of tropical products by the industrialized countries and seldom benefits the populations or the environments of the tropics. Of all the natural substances used by man, gutta-percha is surely among the least well known today, except to three groups of connoisseurs: dentists, who use it to fill cavities; golfers, who hit it with a stick; and historians, to whom it is the stuff with which our ancestors made ashtrays, lamp stands, and submarine cables.* None of them, however, has felt the need to write or give speeches about it in the past 50 years.
Deaf by Design: A Business Argument Against Engineering Disabled Offspring

If Solomon is correct in labeling businesses as community citizens because they “are part and parcel of the communities in which they live and flourish, and the responsibilities that they bear are ... intrinsic to their very existence as social entities,” then it follows that other community citizens have reciprocal duties toward them that they, as community citizens, have to any other community citizen. One of these duties is not to harm needlessly another community citizen without its permission. One issue affecting business is genetically engineering children to have characteristics, e.g., deafness, which render them disabled in work environments. Since business is a very large part of society, citizen responsibilities toward it in regard to intentionally creating deaf children should be examined. It is my contention that designing disabled offspring is unethical on the grounds that it causes undue injury to businesses without their permission in any form.
Calcic paleosols of the Plio-Pleistocene Camp Rice and Palomas Formations, southern Rio Grande rift, USA

Abstract Seventy-four separate paleosols are recognized in the Plio-Pleistocene Camp Rice and Palomas Formations of the southern Rio Grande rift. Seven types of profiles are present: A-Bw-Bk-C, A-Bt-Bk-C, Bw-Bk-C, Bt-Bk-C, Bt-K-C, Bk-C, and Ak. Calcic and petrocalcic horizons (Bk and K) commonly overlain by argillic horizons (Bt) dominate most paleosol profiles. Greater pore size and enhanced permeability, typical of sandy and silty parent material, favored the development of argillic horizons. However, micrite is the dominant form of calcium carbonate in Bk and K horizons regardless of parent material grain size. Non-calcified A horizons are typically lighter in color than adjacent subsurface pedogenic intervals due to their oxidized nature or lower clay content. They are only rarely preserved, probably due to erosion prior to final burial. Calcified root mats (Ak) are not directly associated with other pedogenic horizons. Abundant horizontal roots suggest root mats formed under high water table conditions. Restriction of Ak horizons to the distal piedmont lithofacies supports their development as spring or pond deposits near the toes of alluvial fans. Individual pedogenic horizons can often be traced hundreds of meters to kilometers normal and parallel to a basin's axis. Paleosol maturity and preservation potential are greatest for symmetrical basins, especially where pedogenesis was far removed from active channels within the axial fluvial system or within distal piedmont settings of asymmetrical basins.
Contribution of the Ventromedial Hypothalamus to Generation of the Affective Dimension of Pain

The ventromedial hypothalamus (VMH) is a core structure underlying the generation of affective behaviors to threats. The prototypical threat to an individual is exposure to a noxious stimulus and the dorsomedial division of the VMH (dmVMH) receives nociceptive input. The present study evaluated the contribution of the dmVMH to generation of the affective reaction to pain in rats. Noxious tailshock elicits from rats vocalization afterdischarges (VADs) that have distinct spectrographic characteristics and are a validated model of the affective reaction to pain. VAD-like vocalizations (vocalizations with the same spectral characteristics of VADs) were elicited by stimulation (electrical or chemical) of the dmVMH. Stimulation in the vicinity of the dmVMH was ineffective in eliciting VADs. Manipulation of GABAA neurochemistry within the dmVMH altered the threshold for elicitation of VADs by dmVMH stimulation or tailshock. Administration of the GABAA antagonist bicuculline or the GABAA agonist muscimol into the dmVMH lowered and elevated VAD thresholds, respectively. These treatments did not alter thresholds of other tailshock elicited responses (vocalizations during tailshock or spinal motor reflexes). Bicuculline and muscimol administered into the dmVMH also elevated and lowered the asymptotic level of fear conditioning supported by dmVMH stimulation or tailshock. These findings demonstrate that the dmVMH contributes to the processing of pain affect and that the affective dimension of pain belongs to a broader class of sensory experience that represents threat to the individual.
Centroid-moment tensor solutions for October–December, 1983

Abstract Centroid-moment tensor solutions are presented for 133 earthquakes that occurred during the fourth quarter of 1983.
Effect of Limited Interval Resolution on Single Channel Measurements with Application to Ca Channels

Methods were developed by which measurements of single channel currents, multichannel currents or noise, and whole cell currents could be compared. The methods were applied to a particular set of voltage-dependent membrane channels, the calcium channels. parameters for a variety of identifiable models were estimated by obtaining the best fit to sets of whole cell current data. The parameter estimates were significantly "faster" than those obtained from histograms of measured single channel waiting, closed, and open time intervals (or WCO histograms). The whole cell current parameter estimates were used in Monte-Carlo simulations of single channels, and the effects of the low-pass filtering required to obtain reasonable experimental signal-to-noise ratios were evaluated. Errors that were introduced included the absence of brief open and closed times as well as falsely prolonged open and closed times. An analytical method was developed for computing the effects of these errors on the WCO histograms; following this computation, there was reasonable agreement between the whole cell and single channel measurements. The single channel simulations also allowed us to evaluate the effects of noise and finite record lengths. An unexpected finding was that a bimodal amplitude distributed could be produced by fltering simulated channels having only a single amplitude. This suggests that the occurrence of such a distribution may not necessarily be proof of the existence of two channel types.
Bio-oil Stabilization and Upgrading by Hot Gas Filtration

The objective of this research project was to test the hypothesis that separation of char with its associated mineral matter from pyrolysis vapors before condensation will lead to improved bio-oil ...
Chemotactic activity of C5ades Arg: evidence of a requirement for an anionic peptide 'helper factor' and inhibition by a cationic protein in serum from patients with systemic lupus erythematosus.

Sera from some patients with systemic lupus erythematosus (SLE)∗ contain a uniquely specific, reversible inhibitor of complement (C5)-derived chemotactic activity for polymorphonuclear leukocytes. SLE serum, proven capable of significantly inhibiting C5-derived chemotactic activity in zymosan-treated serum (ZTS), was found incapable of inhibiting the chemotactic activity of the highly purified human anaphylatoxin, C5a (10–20 ng/ml). Similarly, SLE serum was found incapable of inhibiting the chemotactic activity generated in ZTS containing the carboxypeptidase inhibitor, epsilon amino-caproic acid (EACA). EACA protects C5a from the action of the anaphylatoxin inactivator in serum and thereby prevents conversion of C5a to a peptide (C5ades Arg) which is completely devoid of anaphylatoxin activity. Highly purified human C5ades Arg (40–160 μg/ml) was not chemotactic unless assayed in the presence of small amounts of normal human serum. The ‘helper factor’ in normal human serum which permits C5ades Arg to exhibit chemotactic activity was isolated and found to be an anionic polypeptide. The chemotactic activity of C5ades Arg plus normal serum was inhibited significantly by SLE serum. The inhibitor in SLE serum was isolated and determined to be a 69,000 mol. wt cationic protein. These data suggest strongly that the cationic inhibitor in SLE serum acts not on C5a but only on the ‘complex’ of C5ades Arg plus a specific peptide ‘helper factor’. This ‘complex’ accounts for a substantial proportion of the chemotactic activity in ZTS.
Pathogenic mechanisms of myotonic dystrophy.

DM (myotonic dystrophy) is a dominantly inherited genetic disorder that is the most common cause of muscular dystrophy in adults affecting 1 in 8500 individuals worldwide. Different microsatellite expansions in two loci cause different forms of the disease that share similar features: DM1 (DM type 1) is caused by a tri- (CTG) nucleotide expansion within the DMPK (dystrophia myotonica protein kinase) 3′-untranslated region and DM2 (DM type 2) is caused by a tetra- (CCTG) nucleotide expansion within intron 1 of the ZNF9 (zinc finger 9) gene. The pathogenic mechanism of this disease involves the RNA transcribed from the expanded allele containing long tracts of (CUG) n or (CCUG) n . The RNA results in a toxic effect through two RNA-binding proteins: MBNL1 (muscleblind-like 1) and CUGBP1 (CUG-binding protein 1). In DM1, MBNL1 is sequestered on CUG repeat-containing RNA resulting in its loss-of-function, while CUGBP1 is up-regulated through a signalling pathway. The downstream effects include disrupted regulation of alternative splicing, mRNA translation and mRNA stability, which contribute to the multiple features of DM1. This review will focus on the RNA gain-of-function disease mechanism, the important roles of MBNL1 and CUGBP1 in DM1, and the relevance to other RNA dominant disorders.
Variability among breast radiation oncologists in delineation of the postsurgical lumpectomy cavity.

Purpose: Partial breast irradiation (PBI) is becoming more widely used. Accurate determination of the surgical lumpectomy cavity volume is more critical with PBI than with whole breast radiation therapy. We examined the interobserver variability in delineation of the lumpectomy cavity among four academic radiation oncologists who specialize in the treatment of breast cancer. Methods and Materials: Thirty-four lumpectomy cavities in 33 consecutive patients were evaluated. Each physician contoured the cavity and a 1.5-cm margin was added to define the planning target volume (PTV). A cavity visualization score (CVS) was assigned (1–5). To eliminate bias, the physician of record was eliminated from the analysis in all cases. Three measures of variability of the PTV were developed: average shift of the center of mass (COM), average percent overlap between the PTV of two physicians (PVO), and standard deviation of the PTV. Results: Of variables examined, pathologic resection volume was significantly correlated with CVS, with larger volumes more easily visualized. Shift of the COM decreased and PVO increased significantly as CVS increased. For CVS 4 and 5 cases, the average COM shift was 3 mm and 2 mm, respectively, and PVO was 77% and 87%, respectively. In multiple linear regression, pathologic diameter >4 cm and CVS ≥3 were significantly associated with smaller COM shift. When CVS was omitted from analysis, PVO was significantly larger with pathologic diameter ≥5 cm, days to planning Conclusions: Even among radiation oncologists who specialize in breast radiotherapy, there can be substantial differences in delineation of the postsurgical radiotherapy target volume. Large treatment margins may be prudent if the cavity is not clearly defined.
Centrally administered bombesin modulates gastric motility

Abstract Intracerebroventricular bombesin alters arterial pressure and gastrointestinal transit in rats. In order to evaluate the influence of bombesin on arterial and gastric intraluminal pressure in a specific site in the central nervous system, we microinjected bombesin into the medial subnucleus of the nucleus tractus solitarius (mNTS) in 28 rats anesthetized with choralose. Bombesin (78 pmole in 25 nl), but not vehicle, caused an increase of tonic gastric intraluminal pressure (2.6±0.5 cm H 2 O) and of phasic gastric intraluminal pressures but did not acutely alter arterial pressure. The effect on tonic and phasic gastric intraluminal pressure was dose-dependent. The threshold dose was 7.8 pmole. Intravenous bombesin caused a similar dose-dependent rise in tonic gastric intraluminal pressure but did not significantly change the mean amplitude of phasic gastric intraluminal pressures. Transection of the cervical spinal cord and both cervical vagus nerves blocked the effect of centrally but not peripherally administered bombesin. We conclude that bombesin microinjected into the mNTS does not influence arterial pressure but does raise tonic and phasic gastric intraluminal pressures. Bombesin may act in the NTS as a central modulator of gastric motility.
Ophiostoma clavigerum is the mycangial fungus of the Jeffrey pine beetle, Dendroctonus jeffreyi

Dendroctonus jeffreyi and D. ponderosae are sibling species of bark beetles (Coleoptera: Scolyti- dae) with few morphological and molecular genetic differences. The two species are believed to have di- verged relatively recently. Dendroctonus jeffreyi colo- nizes only Pinus jeffreyi, while D. ponderosae colonizes up to thirteen Pinus spp., but not P. jeffreyi. Adult beetles of both D. jeffreyi and D. ponderosae carry sym- biotic fungi in mycangia located on the maxillary car- dines. Dendroctonus ponderosae was known to carry two fungi, Ophiostoma clavigerum and 0. montium, in its mycangia. However, it was not known which fungi might be carried by D. jeffreyi. Fungi were isolated from the mycangia of over 900 D. jeffreyi collected from a large portion of its geographic range. Using morphology, isozyme phenotypes, and growth rates at different temperatures, all isolates from D. jeffreyi mycangia were determined to be 0. clavigerum; 0.
Columbia's first shakedown flight

The space shuttle orbiter Columbia, first of the planned fleet of spacecraft in the nation's space transportation system, will liftoff on its first orbital shakedown flight on or about the 10th of April 1981. Launch will be from the NASA Kennedy Space Center Launch Complex 39A, no earlier than 45 minutes after sunrise. Crew for the first orbital flight will be John W. Young, commander, veteran of two Gemini and two Apollo space flights, and U.S. Navy Capt. Robert L. Crippen, pilot. Crippen has not flown in space.
In vivo targeting of vaccinating tumor cells to antigen-presenting cells by a gene therapy method with adenovirus containing the alpha1,3galactosyltransferase gene.

Poor uptake by antigen-presenting cells (APC) is a major reason for low immunogenicity of autologous tumor vaccines. This immunogenicity may be increased by exploiting the natural anti-Gal antibody that is present in humans as ∼1% of circulating IgG. Anti-Gal binds to α-gal epitopes (Galα1-3Galβ1-4GlcNAc-R) on vaccinating tumor cells and opsonizes them for effective uptake by APC. This epitope is synthesized in human tumor cells by transduction with AdαGT- a replication deficient adenovirus containing the α1,3galactosyltransferase (α1,3GT) gene. Protection against tumors by immunization with AdαGT-transduced tumor cells was studied in α1,3GT knockout (KO) mice, challenged with the highly tumorigenic BL6 melanoma cells. These mice lack α-gal epitopes and can produce anti-Gal. Immunization of KO mice with AdαGT-transduced BL6 cells protects many of the mice against challenge with live BL6 cells lacking α-gal epitopes. Immunization with AdαGT transduced autologous tumor cells may serve as adjuvant immunotherapy delivered after completion of standard therapy. This method may complement another gene therapy method in which GM-CSF-secreting vaccinating tumor cells recruit APC to vaccination sites. Anti-Gal-opsonized vaccinating tumor cells will be effectively internalized by GM-CSF recruited APC and transported to draining lymph nodes for processing and presentation of tumor antigens. Alternatively, injection of AdαGT directly into solid tumor masses of cancer patients may result in anti-Gal-mediated destruction of the transduced tumor cells in a manner similar to xenograft rejection. The subsequent uptake of anti-Gal-opsonized tumor membranes by APC results in their effective transportation to lymph nodes where processed tumor antigens may elicit a protective antitumor immune response.
Effect of the hypocholesterolemic drug AY9944 on developing central nervous system of rats: alteration of endoplasmic reticulum in oligodendroglia.

Unusual alterations of the endoplasmic reticulum were seen in the oligodendroglia of young rats treated with AY9944. They consisted of: 1. random proliferation of membranes within the cytoplasm, some of them with attached ribosomes; 2. multi-layers of paired membranes connected to the cisternae of the rough endoplasmic reticulum which encircled the cytoplasm of oligodendroglia as a whole or focally; 3. formation of numerous small whorls of about 0.5 μm in diameter which are made up of two fused membranes of the rough endoplasmic reticulum.
Chronologic prosthetic management of cleft palate patients

Abstract This article demonstrates the importance of rendering the right treatment to cleft palate patients at the right time. Cleft lip and palate patients require the combined skill and guidance of various specialists for their proper rehabilitation. Meticulous care and proper timing is of prime importance to successful treatment, and the treatment should not be postponed so as to result in embarrassment to the patient. The greatest advances in the management of cleft palate patients have been made since the medical, dental, and speech specialists have used the team approach. As in every team, proper organization with skilled management will produce the most successful results, and render the most efficient service to the patient.
Carnitine: a nutritional, biosynthetic, and functional perspective

Abstract Carnitine status in humans is reported to vary according to body composition, gender, and diet. Plasma carnitine concentration positively correlates with the dietary intake of carnitine. The content of carnitine in foodstuff is based on old and inadequate methodology. Nevertheless, dietary carnitine is important. The molecular biology of the enzymes of carnitine biosynthesis has recently been accomplished. Carnitine biosynthesis requires pathways in different tissues and is an efficient system. Overall biosynthesis is determined by the availability of trimethyllysine from tissue proteins. Carnitine deficiency resulting from a defect in biosynthesis has yet to be reported. The role of carnitine in long-chain fatty acid oxidation is well defined. Recent evidence supports a role for the voltage-dependent anion channel in the transport of acyl-CoAs through the mitochondrial outer membrane. The mitochondrial outer membrane carnitine palmitoyltransferase-I in liver can be phosphorylated and when phosphorylated the sensitivity to malonyl-CoA is greatly decreased. This may explain the change in sensitivity of liver carnitine palmitoyltransferase-I observed during fasting and diabetes. Recently reported data clarify the role of carnitine and the carnitine transport system in the interplay between peroxisomes and mitochondrial fatty acid oxidation. Lastly, the buffering of the acyl-CoA/CoA coupled by carnitine reflects intracellular metabolism. This mass action effect underlies the use of carnitine as a therapeutic agent. In summary, these new observations help to further our understanding of the molecular aspects of carnitine in medicine.
A general mixing equation with applications to Icelandic basalts

Abstract The mixing equation applied by Vollmer [1] to Pb and Sr isotope ratios is shown to be a general equation applicable to consideration of element and isotope ratios. The mixing equation is hyperbolic and has the form: Ax + Bxy + Cy + D = 0 where the coefficients are dependent on the type of plot considered: i.e. ratio-ratio, ratio-element, or element-element. Careful use of this equation permits testing whether mixing is a viable process, places constraints on end member compositions, allows distinction between mixing of sources and mixing of magmas, and should allow distinction between recent mixing and long-term evolution of sources. The available chemical data for postglacial basalts from Iceland and along the Reykjanes Ridge are not consistent with either mixing of magmas or simple mixing of an enriched ocean island source with a depleted ocean ridge source. If the available analyses for basalts are representative of the source regions, the data are consistent with at least two models neither of which can be properly tested with the available data. (1) There are two separate mixing trends: one beneath Iceland with the alkali basalt source and a depleted Iceland source as end members; the second along the Reykjanes Ridge with a heterogeneous ocean ridge basalt source and a source similar to that for intermediate basalts on Iceland as end members. The depleted Iceland source and the depleted ocean ridge source are not the same. (2) The chemistry of the basalts is not determined by mixing. Instead the basalts are derived from a multiplicity of sources with a similar history which have been isolated for hundreds of millions of years.
Relationship between dietary beef, fat, and pork and alcoholic cirrhosis.

Nanji and French [1] investigated the relationship between per-caput consumption of total fat, beef, and pork and for alcohol consumption and rates of mortality for cirrhosis for 16 countries for 1965. The present study reports significant and positive associations for 1996 and 2003 between the following: alcohol consumption and cirrhosis mortality, pork consumption and cirrhosis mortality, the product of alcohol and pork consumption and the product of alcohol and fat consumption. These supportive associations may represent a relationship between the risk of alcoholic cirrhosis and some heretofore unknown dietary or environmental factor related to conditions of pork or fat consumption. Limitations of the study design are discussed.
Risk factors for progression of subclinical diabetic macular oedema

Backgroud/aims The purpose of this study was to determine the incidence of, and risk factors dictating, progression of subclinical macular oedema (SCME) to clinically significant macular oedema (CSME) in patients with diabetes. Methods This was a retrospective, observational case-controlled study at the Veterans Administration (VA) Boston Healthcare System. The study group included subjects with central subfield macular thickness (CSMT) of 200–300 μm, measured by optical coherence tomography, compared with a control group with foveal thickness of Results A total 124 eyes of 73 diabetic patients from the greater Boston area were included in this retrospective study. The study group comprised 52 eyes of 37 diabetic patients with SCME in one or both eyes. The control group included 72 eyes of 36 patients without macular oedema. Sixteen eyes of 13 subjects (35%) progressed to CSME in the study group, compared with six eyes of four subjects (11%) in the control group. Stepwise logistic regression analysis confirmed that prior history of CSME increased the risk of progression (OR 3.69, CI 1.10 to 12.31, p=0.03). Logistic regression analysis also depicted a 15% increase in odds of progression with each 10 μm increase in CSMT (OR 1.15, CI 1.03 to 1.28, p=0.01). Conclusions The results and statistical analyses of this retrospective study suggest that a significant number of patients with SCME ultimately progress to CSME compared with controls. A significant association with prior history of CSME, advancing age and graded increases in CSMT was found.
The Fall Rate of the T-7 XBT

Abstract A theoretical model of expendable bathythermograph (XBT) fall rate is reviewed, and a new form of fall-rate equation is proposed to include new-surface transient effects. Comparisons are made of T-7 XBT and CTD (conductivity, temperature, and depth) depths of thermohaline features off Barbados. Fall-rate equation coefficients are derived and compared with the manufacturer-supplied coefficients. As other investigators have found, the Sippican equation consistently underestimates probe depth by as much as 35 m at 760 m. Analysis yields a new equation, Z=6.798t−0.002383t2−4.01, for depths greater than about 10 m. Considerable probe-to-probe variability is noted and is found to be primarily the result of differences in the linear term or terminal velocity of the probes; variation in effective drag resulting from probe irregularities is the likely cause. Recommendations for additional work are made.
Functional role of delta and theta band oscillations for auditory feedback processing during vocal pitch motor control

The answer to the question of how the brain incorporates sensory feedback and links it with motor function to achieve goal-directed movement during vocalization remains unclear. We investigated the mechanisms of voice pitch motor control by examining the spectro-temporal dynamics of EEG signals when non-musicians (NM), relative pitch (RP) and absolute pitch (AP) musicians maintained vocalizations of a vowel sound and received randomized ±100 cents pitch-shift stimuli in their auditory feedback. We identified a phase-synchronized (evoked) fronto-central activation within the theta band (5-8 Hz) that temporally overlapped with compensatory vocal responses to pitch-shifted auditory feedback and was significantly stronger in RP and AP musicians compared with non-musicians. A second component involved a non-phase-synchronized (induced) frontal activation within the delta band (1-4 Hz) that emerged at approximately 1 second after the stimulus onset. The delta activation was significantly stronger in the NM compared with RP and AP groups and correlated with the pitch rebound error (PRE), indicating the degree to which subjects failed to re-adjust their voice pitch to baseline after the stimulus offset. We propose that the evoked theta is a neurophysiological marker of enhanced pitch processing in musicians and reflects mechanisms by which humans incorporate auditory feedback to control their voice pitch. We also suggest that the delta activation reflects adaptive neural processes by which vocal production errors are monitored and used to update the state of sensory-motor networks for driving subsequent vocal behaviors. This notion is corroborated by our findings showing that larger PREs were associated with greater delta band activity in the NM compared with RP and AP groups. These findings provide new insights into the neural mechanisms of auditory feedback processing for vocal pitch motor control.
Children's perception of emotion and empathic responses.

48 white first grade boys were told the beginning of a cartoon story in which the hero buys a pair of magic glasses with which he can see the invisible Schufloss. One third of the Ss then finished the story when the hero was depicted as feeling either Happy, Fearful, or Neutral. Ss were extremely accurate in identifying the hero's emotional state indicating Ss' social insight. Next Ss were told they could put on a pair of magic glasses and go into a magic forest if they wished to look for the Schufloss. Ss under both emotional conditions reported feeling similar to the hero, suggesring an empathetic response. Finally, the perception of emotion and/or the empathetic response had a significant effect on Ss' subsequent behavior—willingness to enter the forest.
The republic of letters after the Mandela republic

Summary Closely linked to the emergence of modernity, the nation has functioned for literature (and for the novel in particular) as a virtual space, a discursive formation and a mental structure in relation to individual histories and narratives. Thus the nation has served as a reservoir that writers can draw on to fashion stories of the nation. The essay examines the failure of South Africa to function as a unitary nation through specific moments in its literary development, arguing that literature in South Africa has been held hostage by apartheid ‐ both in the historical context of settler oppression and more recently in the “Rainbow Nation” (the period following the election of Nelson Mandela as president in 1994). It remains a presence, a shadow of unpunished wickedness and inequality ignored. The essay ends by drawing analogies to other modern “literatures of the abyss” in which the nation, inasmuch as it does emerge, is narrated with a whimper.
Pulmonary hemodynamics and perioperative cardiopulmonary-related mortality in patients with portopulmonary hypertension undergoing liver transplantation.

In the setting of moderate to severe pulmonary artery hypertension, orthotopic liver transplantation (OLT) may be complicated by pulmonary hemodynamic instability and cardiopulmonary mortality. We retrospectively studied the relationship between cardiopulmonary-related mortality and initial (untreated) pre-OLT pulmonary hemodynamics in 43 patients with portopulmonary hypertension who underwent attempted OLT. Thirty-six patients were reported in 18 peer-reviewed studies, and 7 patients underwent OLT at our institution since 1996. Transplantation procedure outcome, mean pulmonary artery pressure (MPAP), pulmonary vascular resistance (PVR), cardiac output, pulmonary capillary wedge pressure, and transpulmonary gradient (TPG) are summarized. Overall mortality was reported in 15 of 43 patients (35%). Fourteen of the 15 deaths (93%) were primarily related to cardiopulmonary dysfunction. Two deaths were intraoperative, 8 deaths occurred during the transplantation hospitalization, and 4 patients died of cardiopulmonary deterioration posthospitalization. In 4 patients, the transplantation procedure could not be successfully completed. Cardiopulmonary mortality was associated with greater pre-OLT MPAP (49 ± 14 v 36 ± 7 mm Hg; P < .005), PVR (441 ± 173 v 261 ± 156 dynes·s·cm−5; P < .005), and TPG (37 ± 13 v 22 ± 10 mm Hg; P < .005). MPAP of 50 mm Hg or greater was associated with 100% cardiopulmonary mortality. In patients with an MPAP of 35 to less than 50 mm Hg and PVR of 250 dynes·s·cm−5 or greater, the mortality rate was 50%. No mortality was reported in patients with a pre-OLT MPAP less than 35 mm Hg or TPG less than 15 mm Hg. Cardiopulmonary-related mortality in OLT patients with portopulmonary hypertension was frequent and associated with significantly increased pre-OLT MPAP, PVR, and TPG compared with survivors. Treated or untreated, we recommend intraoperative cancellation or advise against proceeding to OLT for an MPAP of 50 mm Hg or greater. Patients with an MPAP of 35 to less than 50 mm Hg and PVR of 250 dynes·s·cm−5 or greater appear to be at high risk for cardiopulmonary-related mortality after OLT. A prospective study is needed to define optimal pretransplantation treatments and pulmonary hemodynamic criteria that minimize OLT mortality associated with portopulmonary hypertension. (Liver Transpl 2000;6:443-450.)
Picosecond studies at 77 K of energy transfer in chloroplasts at low and high excitation intensities

Abstract Spinach chloroplast chlorophyll fluorescence at 685 and 735 nm (F685 and F735) has been time-resolved with a low-jitter streak camera system. Measurements are reported largely for 77 K, using single 30-ps 532-nm excitation pulses with pulse fluences of 2 · 1012 to 2 · 1016 photons · cm−2. A slightly fluence-dependent delay (16 ± 3 ps) found for the rise of F735 relative to F685 is too small to correspond to transfer into the species emitting F735 from the species emitting F685. The rise of F735 is biphasic at lower intensities and monophasic at higher intensity. The delay in the rise of F685 is smaller than approx. 2 ps. The time-resolved F685 is fit with a three-component model in which energy is transferred from a large pool of antenna chlorophylls to a small pool closely connected to the reaction center, all exciton annihilation occurring in the small pool. The F735 biphasic rise and its sensitivity to excitation fluence is explained by a similar but independent model. Data at our lowest intensities are consistent with those obtained by a photon-counting method using very low intensity excitation.
High power emission from strained DQW circular-grating surface-emitting DBR lasers

High power operation of circular-grating surface-emitting distributed Bragg reflector lasers is demonstrated. The structure is a strained InGaAs/GaAs double quantum well grown by one step MBE. Circular gratings are defined by electron beam lithography. A surface emission power over 100mW is obtained.
Speciation of iron and sulfate in acid waters: aqueous clusters to mineral precipitates.

Acid mine drainage (AMD) contaminates surface water bodies, groundwater, soils, and sediments at innumerable locations around the world. AMD usually originates by weathering of pyrite (FeS2) and is rich in Fe and sulfate. In this study, we investigated speciation of FeII, FeIII, and SO4 in acid waters by Fourier transform infrared and X-ray absorption spectroscopy. The molalities of sulfate (15 mmol/kg) and iron (10, 20, and 50 mmol/kg), and pH (1, 2, and 3) were chosen to mimic the concentration of ions in AMD waters. Sulfate and FeII either associate in outer-sphere complexes or do not associate at all. In contrast, sulfate interacts strongly with FeIII. The predominating species in FeIII−SO4 solutions are hydrogen-bonded complexes; inner-sphere complexes account only for 10 ± 10% of the total sulfate. Our results show that the mode of interaction between FeIII and sulfate is similar in aqueous phase and in nanocrystalline precipitate schwertmannite (∼FeO(OH)3/4(SO4)1/8). Because of this similarity, sch...
Cluster configuration method: application to the spectra of π-electron systems

Abstract A simplified method to calculate the excitation spectra of π-electron systems is proposed. The method is based on the assumption that a “cluster” approximation can be applied to excited states. It is demonstrated that, for the low-lying triplet and optically allowed states of butadiene, hexatriene and benzene, the method yields good agreement with complete CI calculations in the Pariser–Pan–Pople approximation.
Yet another proof of the Radon-Nikodým theorem

where b, c, d, e are nonnegative integers. As in the case of F2, since the derivative of f(x) = (h(x))2k(x) is f'(x) = (h(x))2k'(x), it is enough to consider the case when b, c, d, e < 1. If any of b, c, d, e is equal to 0, then f (x) = Ax3 + Bx2 + Cx + D, with A, B, C, D E F4, and f'(x) = Ax2 + C. Since each element in F4 is a square, f'(x) splits in F4. If b = c = d = e = 1, then f(x) = x4 + x and f'(x) = 1 splits in F4. Since f'(x) splits in each case, F4 has Rolle's property. E
Development and Validation of the Smoking Abstinence Expectancies Questionnaire

Introduction Despite evidence that expectancies influence the use and effects of drugs, there are no questionnaires that assess abstinence expectancies among smokers. Such a questionnaire may assist prediction models of successful quitting, enable clinicians to target specific expectancies, and give researchers a broader understanding of cognitive processes that influence smoking. Methods We aimed to develop a questionnaire that assesses, among daily smokers, expected short-term psychological and physiological consequences to (hypothetically) abstaining from smoking. Initial scale items, completed by 326 smokers, were constructed on the basis of theory, empirical evidence, and expert review. Results The final Smoking Abstinence Expectancies Questionnaire (SAEQ) has 28 items and 4 internally consistent subscales: Negative Mood (e.g., "I would feel grouchy"), Somatic Symptoms (e.g., "My throat would feel dry"), Harmful Consequences (e.g., "I would feel like I'm dying"), and Positive Consequences (e.g., "I would feel calm"). The full scale showed good internal consistency (∝ = .86), test-retest reliability over a 2-week span (r = .82), as well as convergent and discriminant validity. Conclusions The present study provides preliminary support for the SAEQ as a tool in smoking cessation research and treatment planning.
A rapid, reliable, and convenient method for the purification of thymidylate synthase from amethopterin-resistant Lactobacillus casei.

Abstract The results presented herein describe the development of a new method for the purification of thymidylate synthase from amethopterin-resistant L. casei . This method includes three chromatographic steps: batchwise CM-Sephadex, Q-Sepharose, and 10-formylfolate-Sepharose affinity steps, and the whole procedure can be performed in three days. Additionally, the procedure has consistently produced enzyme with a specific activity of 3.0 to 3.2. The first step, the batchwise purification of L. casei cell free extracts on CM-Sephadex, resulted in a 120-fold purification with 115% recovery of the activity applied to the resin. The Q-Sepharose purification step yielded a 1.5-fold purification producing enzyme with a specific activity of 2.4 units/mg. As the final step in the sequence, 10-formylfolate-Sepharose affinity chromatography yielded enzyme with a specific activity of 3.0–3.2 units/mg. The entire procedure provided a 230-fold purification with 67% recovery of the activity originally present in the cell free extract. However, the purified enzyme required extensive dialysis to achieve maximal activity. The data presented also clearly demonstrate the resolution of thymidylate synthase on the 10-formylfolate affinity column into forms which have different specific activity values and FdUMP binding ratios. Generally, enzyme with low activity leaches off this affinity matrix first, while enzyme with high activity elutes off last. These results are in accord with the sensitivity of the dimeric thymidylate synthase active site cysteines to oxidization. Consequently, when one of the two active site cysteines is oxidized, the enzyme loses the ability to bind FdUMP at this active site and its specific activity is proportionally lower. Thus, pure thymidylate synthase protein exists as a mixture of heterogeneous activity states. This condition is best examined by performing native PAGE on enzyme that has been incubated with excesses of FdUMP and CH 2 H 4 folate.
Using non-enzymatic chemistry to influence microbial metabolism

The structural manipulation of small molecule metabolites occurs in all organisms and plays a fundamental role in essentially all biological processes. Despite an increasing interest in developing new, non-enzymatic chemical reactions capable of functioning in the presence of living organisms, the ability of such transformations to interface with cellular metabolism and influence biological function is a comparatively underexplored area of research. This review will discuss efforts to combine non-enzymatic chemistry with microbial metabolism. We will highlight recent and historical uses of non-biological reactions to study microbial growth and function, the use of non-enzymatic transformations to rescue auxotrophic microorganisms, and the combination of engineered microbial metabolism and biocompatible chemical reactions for organic synthesis.
Purification and properties of carbamate kinase from Streptococcus faecalis

Carbamate kinase (ATP:carbamate phosphotransferase, EC 2.7.2.2) has been prepared from an arginine-adapted strain of Streptococcus faecalis. Approximately a 500-fold increase in specific activity of the enzyme was achieved. Certain properties of the purified enzyme were studied. 1. 1. The apparent molecular weight as measured by sedimentation equilibrium appears to be about 46 000. 2. 2. The pH optimum for the formation of carbamyl phosphate from ATP and ammonium carbamate is 8.4. 3. 3. Studies with p-chloromercuribenzoate and silver-tris(hydroxymethyl)aminomethane indicate that sulfhydryl groups are essential for enzyme activity. 4. 4. Michaelis constants estimated for adenosine 5′-triphosphate (in the formation of carbamyl phosphate) and for adenosine 5′-diphosphate in the reverse reaction, carbamyl phosphate degradation, were about the same, 1·10−3 M. No such determinations were possible for carbamyl phosphate or ammonium carbonate; when these substrates were studied under comparable conditions non-linear relationships were obtained for Lineweaver-Burk plots.
Nucleic Acid, Purine and Proximate Analyses of Mechanically Separated Beef and Veal

Deoxyribonucleic acid (DNA), ribonucleic acid (RNA), purine (adenine, guanine, hypoxanthine and xanthine) and proximate analyses of mechanically separated (MS) beef and veal were conducted to verify and evaluate changes in nucleic acid content which may result from mechanical separation. DNA and total nucleic acid levels were higher in both MS beef and veal whereas RNA levels were higher only in MS beef compared to hand deboned (HD) counterparts. Adenine, guanine and xanthine levels were higher in MS beef and veal, and hypoxanthine levels were lower compared to HD counterparts. Total purine content of MS beef did not differ from HD beef, whereas the purine content of MS veal was slightly higher than HD veal. It would appear that the addition of MS products to the diet would not significantly alter total purine consumption and hence should pose no risk to hyperuricemic individuals.
Nonparabolicity of the Gray-Tin Γ 8 + Conduction Band

Oscillatory magnetoresistance measurements on gray tin have been extended to Sb-doped samples in the concentration range $8\ifmmode\times\else\texttimes\fi{}{10}^{15}\ensuremath{\le}{N}_{d}\ensuremath{\le}1\ifmmode\times\else\texttimes\fi{}{10}^{19}$ ${\mathrm{cm}}^{\ensuremath{-}3}$. The field-modulation technique was used, and period and amplitude measurements were made with the field in principal crystallographic planes. The field and temperature dependence of the amplitude was analyzed in terms of an empirically modified expression which incorporates the inhomogeneity temperature ${T}_{i}$. The analysis yielded principal values of the effective mass, the Dingle temperature, and ${T}_{i}$. The observed increase in effective mass with carrier concentration is compared with the predictions of Kane's theory for InSb. For ${{\ensuremath{\Gamma}}_{8}}^{+}$ electron concentrations ${n}_{0}$ less than 4.7\ifmmode\times\else\texttimes\fi{}${10}^{17}$ ${\mathrm{cm}}^{\ensuremath{-}3}$, the observed nonparabolicity is consistent with Kane's theory with the following parameters: bandedge density-of-states mass, $0.0236{m}_{e}$; ${{\ensuremath{\Gamma}}_{7}}^{\ensuremath{-}}\ensuremath{-}{{\ensuremath{\Gamma}}_{8}}^{+}$ energy gap, 0.634 eV; and matrix-element energy ${E}_{P}=39$ eV. For larger ${n}_{0}$ values, at which the ${{L}_{6}}^{+}$ subsidiary minima are populated, the mass increases more rapidly than predicted. The Fermi level is evaluated taking account of the observed nonparabolicity.
Strategic behaviour and a notion of ex ante efficiency in a voting model

A person is said to prefer in the stochastic dominance sense one lottery-over-outcomes over another lottery-over-outcomes if the probability of his (at least) first choice being selected in the first lottery is greater than or equal to the analogous probability in the second lottery, the probability of his at least second choice being selected in the first lottery is greater than or equal to the analogous probability in the second lottery, and so on, with at least one strict inequality. This (partial) preference relation is used to define straightforwardness of a social choice function that maps profiles of ordinal preferences into lotteries over outcomes. Given a prior probability distribution on profiles this partial preference ordering (taking into account the additional randomness) is used to induce a partial preference ordering over social choice functions for each individual. These are used in turn to define ex ante Pareto undominated (efficient) social choice functions. The main result is that it is impossible for a social choice function to be both ex ante efficient and straightforward. We also extend the result to cardinal preferences and expected utility evaluations.
INTERACTIONS BETWEEN LOCAL DYNAMICS AND DISPERSAL : INSIGHTS FROM SINGLE SPECIES MODELS

Population persistence in patchy environments is expected to result from an interaction between local density dependence, dispersal, and spatial heterogeneity. Using two-patch models of single species, I explore two aspects of this interaction that have hitherto received little attention. First, how is the interaction affected when local density dependence changes from negative (logistic) to positive (Allee)? Second, how does dispersal mortality influence persistence ? When local dynamics are logistic, dispersal changes the strength of negative density dependence within patches without much between-patch effect. For example, dispersal mortality reduces the population growth rate and counteracts the tendency towards complex dynamics. Density-dependent disperal amplifies the nonlinearity in the growth rate, thus opposing the stabilizing effects of dispersal mortality. Spatial heterogeneity has little or no effect on stability. In contrast to the logistic, dispersal under Allee dynamics creates between-patch effects that bring about a qualitative change. Patches that fall below the Allee threshold are rescued from extinction by immigrants from patches that are above the threshold. Density-dependent dispersal enhances this rescue effect. Persistence below the extinction threshold is contingent on spatial heterogeneity. Dispersal mortality is of little or no consequence.