cssi/SciSciGPT-SciSciNet huggingface dataset:
Radiotherapy and chemotherapy in combined clinical trials: problems and promise.

Abstract The recent clinical experience with combined radiotherapy and chemotherapy has been reviewed. Trials using these two modalities together have increased greatly since initial studies in Wilms tumor and in acute leukemia. Both unusual toxicities and therapeutic synergisms have been uncovered. The aim of this combined therapy is that of either local “radiopotentiation” or chemotherapeutic control outside the radiation field, or both. The sequence, dose, and schedule relationship has been empirically established and exploration for optimal sequences has been minimal. Nevertheless, great experience has accrued in hematologic malignancies. In addition, an important application of combined modality therapy has been the treatment of childhood solid tumors, with striking successes in Wilms tumor, Ewing's sarcoma and rhabdomyosarcoma. Many trials have also begun in lung cancer (small cell carcinoma), breast cancer, gynecologic and gastrointestinal malignancies, epidermoid cancer of various sites in the head and neck, and central nervous system tumors. However, the list of complications from combined treatment is also growing. Enhancement of hematologic toxicities and the predisposition to higher secondary neoplasms, particularly acute leukemia, have been known for some time, although they are receiving increasing attention as combined therapy extends to more favorable groups of patients. Newly recognized complications are the unique development of the accelerated bleomycin induced pulmonary fibrosis with preceding mediastinal irradiation, the finding of anthracycline cardiomyopathy potentiated by preceding cardiac irradiation, and the leukoencephalopathy following methotrexate and cranial irradiation. The therapeutic promise of combined modality treatment has hardly begun to be explored. Experimental study of radiation-chemotherapy interactions constitutes an important area of investigation.
Knowledge management revisited: Old Dogs, New tricks

The article considers the (old) field of Knowledge Management (KM) and examines the factors that led to its decline over the last several years. It also argues that the demise of knowledge management is premature and that it is time to revisit the field and take it to the “next level” of academic research and business practice. Then the article presents a proposal of how to do it by deploying certain “new tricks,” that is, various modern developments in the fields related to KM that can make a difference and solve the old problems of knowledge management.
Modeling of transient permeate flux in cross-flow membrane filtration incorporating multiple particle transport mechanisms

Dominant mechanisms of particle transport in cross-flow membrane filtration are unified to obtain a generalized model for time-dependent permeate flux. The unified model extends an earlier model based on shear-induced diffusion and a concentrated flowing layer to include Brownian diffusion and inertial lift. It is applicable over a broad range of contaminant sizes encompassing macromolecules, colloidal and fine particles, and large particles. The combined theory predicts an unfavorable particle size, of the order of 10−1 μm, where the net back-transport away from the membrane attains a minimum, leading to maximum cake growth. For the system simulated in this work, this implies minimum permeate fluxes in the size range of 0.01–0.1 μm, depending on the operating time. Inside-out hollow-fiber geometry is predicted to be favorable for feed suspensions with small particles and/or low concentrations which form thin resistive cakes. However, larger particles, which form thick cakes, may result in reduced surface area available for filtration due to curvature effects in inside-out membranes, making the slit or outside-in geometry more favorable for these particles. Fine particles (< 0.1 μm) are predicted to demonstrate mass-transport limited behavior. For larger particles, different combinations of fiber radius and cross-flow velocity, resulting in the same shear rate, demonstrate different permeate fluxes.
If HIV / AIDS is punishment who is bad?

HIV/AIDS strikes with the greatest frequency in sub-Saharan Africa, a region lacking resources to deal with this epidemic. To keep millions more people from dying, wealthy countries must provide more help. Yet deeply ingrained biases may distance the sick from those who could provide far more aid. One such prejudice is viewing disease as punishment for sin. This 'punishment theory of disease" ascribes moral blame to those who get sick or those with special relations to them. Religious versions hold that God punishes them in order to castigate, encourage virtue, warn, rehabilitate, or maintain some cosmic order. Its various religious and secular forms are untenable; they lack cogency, risk blaming people unjustly, and jeopardize compassionate care for people. These views are not only irrational but also dangerous because they influence policies and cost lives. We need to cooperate and respond as befits this global public-health disaster and not engage in the misguided and bad faith activity of dividing the world into the blameworthy and blameless.
Lignin Effect on Calcium Absorption in Rats

The effect of lignin on calcium absorption was studied in a rat model. Lignin preparations were isolated directly from wheat bran and from kale by two treatments, enzymatic and acidic. Calcium absorption in the presence or absence of isolated wheat bran lignin, isolated kale lignin, commercially available pine lignin, and wheat bran was determined by femur uptake of 45Ca. The fractional calcium absorption of wheat bran was significantly lower than for the control. However, there were no differences in calcium absorption between the various lignin sources and the control without lignin. Thus, lignin is probably not inhibitory to calcium absorption in plant foods.
Comparison of dialysis and solid-phase extraction for isolation and concentration of dissolved organic matter prior to Fourier transform ion cyclotron resonance mass spectrometry

We compare two methods, solid-phase extraction (SPE) and dialysis, commonly used for extraction and concentration of dissolved organic matter (DOM) prior to molecular characterization by electrospray ionization (ESI) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry. Spectra of DOM samples from Minnesota and Sweden peatlands that were extracted with styrene divinyl benzene polymer SPE sorbents included ions with formulas that had higher oxygen to carbon (O/C) ratios than spectra of DOM from the same samples after de-salting by dialysis. The SPE method was not very effective in extracting several major classes of DOM compounds that had high ESI efficiencies, including carboxylic acids and organo-sulfur compounds, and that out-competed other less-functionalized compounds (e.g., carbohydrates) for charge in the ESI source. The large abundance of carboxylic acids in the dialysisextracted DOM, likely the result of in situ microbial production, makes it difficult to see other (mainly hydrophilic) compounds with high O/C ratios. Our results indicate that, while dialysis is generally preferable for the isolation of DOM, for samples with high microbial inputs, the use of both isolation methods is recommended for a more accurate molecular representation.
Unfinished Business: Radiation Exposure Compensation Act (RECA) for Post-1971 U.S. Uranium Underground Miners

Congress enacted the Radiation Exposure Compensation Act (RECA) in 1990 and amended it in 2000. Included for compensation were underground uranium miners who developed health problems related to radiation exposures. Neither the 1990 Act nor the 2000 Amendments covered post-1971 workers. In this article, we will examine regulatory history and scientific evidence used for the passage of RECA for the pre-1972 miners and will present evidence supporting the inclusion of the post-1971 workers.
Wake Closure and Afterbody Heating on a Mars Sample Return Orbiter

Aeroheating wind-tunnel tests were conducted on a 0.028-scale model of an orbiter concept considered for a possible Mars sample return mission. The primary experimental objectives were to characterize hypersonic near-wakeclosure and to determine if shear layer impingement would occur on the proposed orbiter afterbody at incidence angles necessary for a Martian aerocapture maneuver. Global heat transfer mappings, surface streamline patterns, and shock shapes were obtained in the NASA Langley Research Center 20-Inch Mach 6 Air and CF 4 Tunnels for postnormal shock Reynolds numbers (based on forebody diameter) ranging from 1.4 × 10 3 to 4.15 x 105, angles of attack ranging from -5 to 10 deg at 0-, 3-, and 6-deg sideslip, and normal shock density ratios of 5 and 12. Laminar, transitional, and turbulent shear layer impingement on the cylindrical afterbody was inferred from the measurements and resulted in a localized heating maximum that ranged from 40 to 75 % of the reference forebody stagnation point heating.
Resolution by high pressure liquid chromatography of intracellular and extracellular free amino acids of a nitrogen deficient marine diatom, Skeletonema costatum (Grev.) Cleve, pulsed with nitrate or ammonium

Abstract Nitrate and ammonium were added to nitrogen (N) deficient, batch cultures of Skeletonema costatum (Grev.) Cleve. The range of total internal free amino acids (IN FAAs) after N perturbations was 13.0–28.5 mM, while the total external FAAs (EX FAAs) varied from 3.9–17.5 μM. The total basic IN FAAs (and the total basic IN FAA N) predominated over the acidic and neutral IN FAAs (and acidic and neutral IN FAA N) after 50 h of N deficiency and after the N perturbations. Ornithine, a non-protein basic amino acid, was the most abundant individual IN FAA in N deficient cells, accounting for 43% of the total IN FAAs. All internal FAAs increased more quickly after the NH4+ addition than after the NO3− addition. During the assimilation of either N addition, ornithine increased to a temporary peak concentration more rapidly than any other observed IN FAAs, and contributed up to 80% of the total IN FAA pool. After most of the respective N additions had been assimilated, and as free ornithine began to decrease, glutamine and glutamate increased to form a combined contribution of 30% of the total IN FAA pool. The increases of internal free glutamine and glutamate occurred more rapidly with the addition of NH4+ than with NO3−, and these increases did not occur until the internal NH4+ was depleted. The EX FAA did not undergo a distinct cycling in response to the NO3− or NH4+ additions, as was observed with the IN FAAs. In contrast to the composition of the IN FAAs the most abundant EX FAAs were histidine (relatively sparse IN FAA), glutamate, aspartate, ornithine, and lysine.
Redox-induced polymerisation/depolymerisation of metallo-supramolecular polymers

Redox-responsive metallo-supramolecular polymers (MSPs), consisting of a ditopic ligand end-capped poly(tetrahydrofuran) (pTHF) macromonomer self-assembled with copper ions, have been developed where the degree of polymerization of the MSP, and therefore the viscosity of its solutions, depends on the oxidation state of the copper ion. We use a combination of UV-Vis, viscosity, light scattering, cyclic voltammetry and SAXS to show that the ligands, 2,6-bis(N-methylbenzimidazolyl)pyridine (MeBip), at the ends of the pTHF, bind copper(II) in a 2 : 1 ratio and copper(I) in a 2 : 2 ratio in solution. Thus at fixed 1 : 1 or 1 : 2 stoichiometry of macromonomer to copper ions the viscosity of their solutions shows dramatic changes in response to addition of a chemical oxidant (nitroso tetrafluoroborate) or reductant (aqueous ascorbic acid).
Employment and career prospects for bioengineers.

Fueled by a stong demand for a talented workforce and increased government and private funding, academic programs in bioengineering are developing rapidly.
CLINICAL EXPERIENCE WITH HIGH FREQUENCY JET VENTILATION (HFJV) IN PEDIATRIC PATIENTS

HFJV has been developed as an alternate mode of mechanical ventilation which employs very small tidal volumes at rapid rates. Its theoretical advantages over conventional ventilation (CV) include less barotrauma and less cardiovascular depression due to lower airway pressures. While HFJV has been used successfully for treating respiratory disorders in adults and neonates, experience with this mode of ventilation in older children is limited. We have reviewed our experience with 22 pts, aged 2 wks to 20 yrs (m±SD 5.1±6.7 yrs) who received HFJV for treatment of respiratory failure (RF) not adequately controlled with CV. The primary diagnosis was pneumonia in 13 pts, ARDS in 7 pts, and cardiogenic shock in 2 pts. Indications for switching from CV to HFJV were high peak inspiratory pressure (PIP) in 14 pts (64%), refractory hypercarbia in 5 pts (23%) and refractory hypoxemia in 3 pts (13%). Nine pts (41%) had one or more pneumothoraces (PN) during CV. HFJV was initiated with driving pressures of 6-43 psi (m±SD 18.6±9.8 psi) and rates of 95-233 breaths/min (m±SD 145±34). PIP decreased from 61±17 cm H2O during CV to 46±15 cm H2O during HFJV and ΔP (PIP-PEEP) decreased from 49±15 cm H2O to 32±15 cm H2O (both p<0.001). Mean PEEP increased slightly, from 11.6±5 cm H2O to 13.5±7 cm H2O (NS). Partial pressure of CO2 was lower during HFJV (40±13 vs 46±10 mmHg, p < 0.05); oxygenation, as measured by arterial:alveolar pO2, did not change. In 4 pts, HFJV was discontinued within 6 hrs due to worsening arterial blood gases. Of the remaining pts, nine were successfully weaned from HFJV and survived, and 9 expired while receiving HFJV. Duration of HFJV ranged from 2 hrs-20 days (m±SD 6.2±5.7 days), and was shorter in survivors (m±SD 5.7±3 days) than in nonsurvivors (m±SD 9.4±7 days). PN developed in 12 pts (54%) during HFJV; no other complications were notea. HFJV may successfully treat some cases of RF refractory to CV.
Photoelastic properties of amorphous As2S3

Abstract The piezobirefringence of amorphous As 2 S 3 was measured in the wavelength range 0.69 to 1.15 μ, and the pressure dependence of the index of refraction was determined at 0.633 and 1.15μ. The dispersion of the photoelastic constants of As 2 S 3 is discussed using a one-oscillator model, and compared with the results of a similar analysis performed on GaAs.
New options in contraception for teenagers.

New contraceptive methods bring unique side effect profiles and delivery systems that may improve overall contraceptive compliance especially among teenagers who are more prone to misuse from a wide array of side effect and compliance issues. Even the most accepted method however will not provide effective contraception if the process by which contraception is provided fails to address the unique concerns and lifestyle issues of each individual adolescent. (authors)
Effect of Athyroid State on Vascular Reactivity and Arterial Pressure in Neurogenic and Renal Hypertensive Dogs

Since vascular responsiveness to adrenaline, noradrenaline, renin and angiotonin is reduced by suppression of thyroidal function in normotensive dogs, it was a possibility that in neurogenic and renal hypertensive animals suppression of thyroidal function might be associated with decrease in arterial pressure. This possibility was not confirmed, hypertension persisting unaltered in both groups of hypertensive animals over long periods of observation. Changes in vascular reactivity were slight in comparison with those associated with the athyroid state in normotensive dogs.
Structure of the ZnSe/GaAs heteroepitaxial interface

Interfaces of pseudomorphic (100) ZnSe/GaAs heterostructures grown by molecular beam epitaxy have been studied by transmission electron microscopy. The observation of three different heterostructures suggests the existence of a transition structure at the ZnSe/GaAs interfaces which have formed on As‐deficient GaAs surfaces. The transition structure appears as a bright line in dark field images of the 200 reflection, while it becomes a dark line in dark field images of the 400 reflection. These observations are explained by assuming the existence of an interface layer which has a zinc blende type structure having vacancies in one of the face centered cubic sublattices.
Spatial association of photosynthesis and chemical defense in Arabidopsis thaliana following herbivory by Trichoplusia ni

Because they share common precursors and require significant amounts of energy, photosynthesis and defense against herbivores and pathogens may be inversely related. This relationship was examined in Arabidopsis thaliana exposed to herbivory by Trichoplusia ni neonates. The spatial pattern of photosynthesis was compared statistically with that of induction of the defense-related cinnamate-4-hydroxylase (C4H) gene across individual leaves exposed to herbivory in transgenic plants harboring a C4H:GUS gene fusion. In portions of the leaf where C4H:GUS expression was upregulated, photosynthesis was depressed, while non-photochemical quenching was increased, suggesting a trade-off between these two processes. However, photosynthetic damage spread further into surrounding areas than the induction of C4H:GUS expression. Photosynthetic depression was observed up to 1 mm from the edges of holes, whereas C4H:GUS induction typically was limited to about 0.5 mm or less from edges. Other mechanisms may be responsible for the spread of photosynthetic damage beyond where C4H-related defense was induced. Alternatively, C4H induction may reflect a subset of defensive responses more limited in their spatial distribution than the downregulation of photosynthesis. The suppression of photosynthesis in remaining leaf tissue represents a 'hidden cost' of herbivore damage.
Shame in Two Cultures: Implications for Evolutionary Approaches

Cross-cultural comparisons can a) illuminate the manner in which cultures differentially highlight, ignore, and group various facets of emotional experience, and b) shed light on our evolved species-typical emotional architecture. In many societies, concern with shame is one of the principal factors regulating social behavior. Three studies conducted in Bengkulu (Indonesia) and California explored the nature and experience of shame in two disparate cultures. Study 1, perceived term use frequency, indicated that shame is more prominent in Bengkulu, a collectivistic culture, than in California, an individualistic culture. Study 2, comparing naturally occurring shame events (Bengkulu) with reports thereof (California), revealed that shame is associated with guilt-like accounts in California but not in Bengkulu, and subordinance events in Bengkulu but not in California; published reports suggest that the latter pattern is prominent worldwide. Study 3 mapped the semantic domain of shame using a synonym task; again, guilt was prominent in California, subordinance in Bengkulu. Because shame is overshadowed by guilt in individualistic cultures, and because these cultures downplay aversive emotions associated with subordinance, a fuller understanding of shame is best arrived at through the study of collectivistic cultures such as Bengkulu. After reviewing evolutionary theories on the origins and functions of shame, I evaluate these perspectives in light of facets of this emotion evident in Bengkulu and elsewhere. The available data are consistent with the proposition that shame evolved from a rank-related emotion and, while motivating prestige competition, cooperation, and conformity, nevertheless continues to play this role in contemporary humans.
Equitable distribution of indivisible objects

Abstract Deterministic and randomized solutions are developed for the problem of equitably distributing m indivisible objects to n people (whose values may differ), without the use of outside judges or side-payments. Several general bounds for the minimal share are found; a practical method is given for determining an optimal lottery and the largest minimal share; and the case of repeated allocations is analyzed.
A study of the (n, d) reaction at 152 MeV

Abstract Proton pick-up by 152 MeV neutrons has been observed in 4He, 6Li, 7Li and 12C. Because an energy resolution of 10 MeV has been achieved, we have been able to separate the pick-up from different shells.
Executive Decision Making: Linking Dynamic Managerial Capabilities to the Resource Portfolio and Strategic Outcomes

To more completely understand the basis for firm performance differences, we need greater clarity on the drivers of differentiation in managerial strategic decision making, as well as on the impact these decisions have on the composition and configuration of the firm’s resource portfolio. In this article, we provide an integrative framework that illustrates how strategic leaders influence firm strategy and performance. Our model clarifies the role that dynamic managerial capabilities play in fashioning a unique bundle of resources for the firm, thus leading to differences in firm strategies and performance outcomes. The process is illustrated by examples drawn from industry.
Total synthesis of hectochlorin.

Hectochlorin (1) is a marine natural product with significant fungicidal activity. A synthesis effort was initiated to develop a flexible route to hectochlorin which would allow access to analogues with potentially improved activity and/or attributes relative to the natural product. A successful total synthesis of hectochlorin is described.
Subcutaneous, catheter-related inflammation in a rabbit model correlates with peripheral vein phlebitis in human volunteers

In the development of a polyurethane vascular catheter with anti-infective properties, it became desirable to develop a measure of tissue inflammation. This was investigated in a rabbit model by implanting uncoated catheters and catheters coated with heparin (HEP), chlorhexidine (CH), or CH/HEP in the subcutaneous space with or without 10(4) Staphylococcus aureus. At intervals of 2, 4, and 7 days after implantation, animals were sacrificed; tissue blocks containing catheters were removed and preserved with formaldehyde; and sections were stained with hematoxylin and eosin. Using a histologic index, 240 sections (10 for each experimental condition) were evaluated by two investigators blinded to experimental conditions. Uncoated catheters or catheters coated with CH alone had a lower histologic index (less inflammation) than catheters coated with HEP alone or CH/HEP (P < .05). When catheters were inoculated with S. aureus, those coated with CH, with or without HEP, had a lower histologic index than uncoated catheters (P < .05). Next, 30 volunteers had a control catheter inserted in a vein in one forearm and a catheter coated with either CH alone or CH/HEP in a vein in the other forearm. After 96 h of observation there was a greater risk of phlebitis associated with CH/HEP catheters than control catheters (P < .05), and no difference in the risk of phlebitis between CH catheters and control catheters (P = 0.43). Thus, the amount of inflammation around the catheter in the subcutaneous space of rabbit correlated with the risk of peripheral vein phlebitis.
Third-Party “Hatchet” Ads: An Exploratory Content Study Comparing Third-Party and Candidate Spots From the 2004 Presidential Election

The Supreme Court's 2010 Citizens United ruling lifted several key rules limiting electioneering communication. These changes are predicted to have significant effects on political campaigns. Namely, the ruling allows third-party sponsored electioneering up until Election Day. Because of the widespread presence of third-party issue advertising in 2004 presidential race, that election offers researchers one of the first opportunities to compare the content of third-party spots with candidate sponsored spots. This study examined the differences between third-party and candidate-sponsored spots, to look at differences in areas of “magic word” inclusion (e.g., “vote for …,” “vote against …”), negativity, and overall message consistency. Our findings show that few candidates use magic words, third-party spots were significantly more negative, addressed more issues than candidate spots, and made fewer explicit references to issues. Based on our results, we recommend future research on the effects of ad negativi...
Suicide Prevention in Schools: Court Cases and Implications for Principals:

This article discusses the role of educators in suicide prevention. First, the incidence of adolescent suicide in the United States is discussed. Next, case laws related to suicide in educational settings are reviewed. Court rulings indicate that educators can be found negligent in cases involving suicide only if the court finds that they owed a duty to the victim. Finally, suggestions for school principals related to implementing suicide prevention programs in school settings are presented.
Genesis of complex fractionated atrial electrograms in zones of slow conduction: a computer model of microfibrosis.

Background Complex fractionated atrial electrograms are used as potential targets for catheter ablation therapy of atrial fibrillation. Although fibrosis has been associated with the presence of fractionated electrograms, characterizing the substrate through the inspection of electrograms is challenging. Objective This study sought to determine how progression of microfibrosis and slow conduction affect electrogram morphology. Methods A microstructure computer model representing a monolayer of cardiac cells was developed. Slow conduction was induced by: (1) sodium channel blockade, (2) uniform reduction in cell-to-cell coupling, and (3) microfibrosis incorporated as a set of collagenous septa disconnecting transverse coupling. The density (0 to 30%) and length (30 to 945 μm) of these collagenous septa were varied. Unipolar and bipolar electrograms were computed during paced rhythm for a set of electrodes with different tip sizes. Results The analysis of unipolar electrograms with realistic temporal and spatial filtering showed that increasing the density and length of collagenous septa decreased conduction velocity by up to 75% and increased the amount of fractionation (up to 14 deflections) and asymmetry of the electrograms. In contrast, slow conduction induced by sodium channel blockade or uniformly reduced coupling did not result in electrogram fractionation. When a larger electrode was used, electrogram amplitude was smaller and fractionation increased in a substrate-dependent way. Conclusion Microscale obstacles cause significant changes to electrogram waveforms. Conduction velocity and electrogram amplitude and degree of fractionation can be used to discriminate the nature of the substrate and characteristics of fibrosis, giving rise to slow conduction.
Measures of Geologic Isolation

Isolation in a geologic setting has been the generally favored solution to the high-level radioactive waste (HLW) problem since a scientific basis for nuclear waste management began to be formulated over half a century ago. Although general features of suitable settings have been enumerated, quantitative measures of the safety of geologic isolation of HLW are challenging to devise and to implement. Some regulatory measures of isolation for the proposed repository at Yucca Mountain, Nevada, have be devised and revised involving considerations of global releases, groundwater travel time, and time and space scales for isolation. In current Yucca Mountain specific regulations, the measure of long-term safety hinges on probabilistic estimates of radiation doses to the average member of a maximally exposed group of people living about 18 km down the groundwater flow gradient within 10,000 years after permanent closure of the repository. From another perspective, hydrogeochemical studies provide quantitative measures of system openness and the ability of geologic systems to isolate HLW. Hydrogeochemical data that bear on geologic isolation of HLW at Yucca Mountain include precipitation of radionuclides in stable mineralogical products of spent fuel alteration, ages of natural secondary mineralization in the mountain, uranium decay-series isotopic data for system openness, bomb-pulse isotope occurrences, and ambient carbon-14 distributions.
Onset of cerebral electrical activity associated with behavioral sleep and attention in the developing chick.

Bipolar electrical recordings from the cerebral lobes of chick embryos and of freely moving chicks after hatching indicate that spontaneous electrical activity begins about the eleventh to thirteenth day of incubation, but electroencephalographic patterns characteristic of behavioral sleep or attention appear within six hours after hatching. High amplitude, slow waves, are characteristic of behavioral sleep; low amplitude, fast waves are characteristic of behavioral attention. During sleeping postures the electroencephalographic record shows brief cyclic episodes of lower voltage fast waves (paradoxical sleep) and these cycles appear more definitely as the chick grows older. When the act of waking from sleep is associated with the opening of only one eye, the lower voltage, fast waves may appear only in the contralateral lobe, while the ipsilateral lobe shows the high amplitude slow waves. In the less mature chicks, the electrical waves are slower, less regular, and of smaller amplitude, especially during sleep, furthermore the cyclic episodes of activated sleep are less distinct and the span of attention is more brief. Although chick embryos may move following tactile stimulation, the response is probably due to reflex arcs involving lower nervous centers since the cerebral lobes do not show the transition to lower voltage faster waves characteristic of attention. After hatching electroencephalographic patterns associated with sleeping postures show more conspicuous developmental changes than those associated with attention.
Examination of tubulin-nucleotide interactions by protein fluorescence quenching measurements

Abstract The fluorescence emission spectrum of bovine brain tubulin is quenched upon binding of GTP, GMPP(NH)P, or GMPP(CH2)P to the tubulin·GDP complex. At saturating levels of GTP or its nonhydrolyzable β-γ analogues, the partially quenched spectrum is virtually identical, suggesting that a similar conformational state is attained in each case. Titrations with each ligand yielded dissociation constants of 0.8, 3, and 3μM for GTP, GMPP(NH)P, and GMPP(CH2)P; in all cases the stoichiometry is essentially one molecule of nucleotide per dimer. It is concluded that GDP and GTP stabilize different conformations and that the nonhydrolyzable analogues mimic the binding of GTP. This may be related to the ability of GMPP(NH)P and GMPP(CH2)P to maintain a pre-assembly conformation similar to tubulin·GTP.
Williams syndrome: An exploration of neurocognitive and genetic features

Abstract We report here on significant attempts to forge links between neurodevelopmental disorders, development of specific neuropsychological abilities, and the functional establishment of patterns of brain organization. Such research programs are providing converging evidence for the coherence or dissociability of components of cognition (e.g. language, spatial cognition) and will allow development of theoretical explanations for the underlying architecture of human cognition. Williams syndrome involves focal rather than generalized cognitive deficits, and offers an important opportunity for linking brain findings to specific atypical cognitive profiles. The unusual neurocognitive profile of Williams syndrome makes it a compelling model of the pathways between genes and human cognition. It is becoming clear that the syndrome's unique genomic organization may also make it an important model of human chromosomal evolution and disease. These studies with a specific neurodevelopmental disorder that presents a rare dissociation of higher cortical functioning may provide opportunities to explore some of the central issues of cognitive neuroscience that tie cognitive functions to brain organization and ultimately to the human genome.
Characteristics and management of superior semicircular canal dehiscence.

Objectives To review the characteristic symptoms of superior semicircular canal dehiscence, testing and imaging of the disease, and the current treatment and surgical options. Results and Conclusions Symptoms of superior semicircular canal dehiscence (SSCD) include autophony, inner ear conductive hearing loss, Hennebert sign, and sound-induced episodic vertigo and disequilibrium (Tullio phenomenon), among others. Potential etiologies noted for canal dehiscence include possible developmental abnormalities, congenital defects, chronic otitis media with cholesteatoma, fibrous dysplasia, and high-riding jugular bulb. Computed tomography (CT), vestibular evoked myogenic potentials, Valsalva maneuvers, and certain auditory testing may prove useful in the detection and evaluation of dehiscence syndrome. Multislice temporal bone CT examinations are normally performed with fine-cut (0.5- to 0.6-mm) collimation reformatted to the plane of the superior canal such that images are parallel and orthogonal to the plane. For the successful alleviation of auditory and vestibular symptoms, a bony dehiscence can be surgically resurfaced, plugged, or capped through a middle fossa craniotomy or the transmastoid approach. SSCD should only be surgically treated in patients who exhibit clinical manifestations.
Genital Tract Papillomavirus Infection in Children

• Genital tract papillomas in five children were examined for the presence of human papillomavirus (HPV) DNA by molecular hybridization. Papillomavirus DNA was detected in each sample and was identified as HPV-6 (three cases), HPV-6 or HPV-11 (one case), or HPV-16 (one case). These viruses are the same as are responsible for genital papillomas (condylomata) of adults. The transmission of adult genital tract viruses to children occurs primarily by a venereal route but may occur by a nonvenereal route. (Arch Dermatol1986;122:1129-1132)
Regional distribution of trifluoroacetate in surface waters downwind of urban areas in Northern California, U.S.A.

Trifluoroacetate (TFA), a breakdown product of the hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs), has been found at higher concentrations in surface waters near urban areas compared to globally remote sites, but the scale of the urban enrichment, namely local or regional, is unknown. To determine the scale of urban enrichment of TFA in Northern California, a series of streams were sampled in 1998 along a transect upwind and downwind of the San Francisco and Sacramento metropolitan areas. In addition, 17 remote sites were sampled in British Columbia and the Yukon Territory, Canada and in Alaska, U.S.A. to determine the baseline TFA concentrations in Northern Hemisphere surface waters. The results showed elevated TFA concentrations in surface waters around and immediately downwind of urban areas. The enrichment was approximately 5−6 times higher than the concentrations in upwind sites. The northern remote sites showed a median TFA concentration of 21 ng/L, which was statistically indistingu...
Iterative projection onto convex sets using multiple Bregman distances

A number of inverse problems, in image reconstruction and elsewhere, can be formulated in terms of finding a vector in the intersection of certain convex sets that serve to constrain the solution. Finding such vectors is called the `convex feasibility problem' (CFP). Algorithms to solve the CFP are usually iterative `projection onto convex sets' (POCS) methods that employ orthogonal or more general projections onto the individual convex sets; Bregman's `successive generalized projection' (SGP) is one such method. When the intersection of the convex sets is heterogeneous one may wish to optimize a certain function over that intersection; then we have a constrained optimization problem. Generalized projections come from generalized distances, typically Bregman distances, chosen to incorporate prior information, such as non-negativity, about the image being reconstructed. Calculating a generalized projection onto a convex set can be simplified if the generalized distance can vary with the convex set. Censor and Elfving have discovered a simultaneous multiprojection algorithm that permits just such variation. Because simultaneous methods, which use all the convex sets at each step, can be slow to converge, there is considerable interest in faster, block-iterative methods that employ only some of the convex sets at each step. In this paper we present the first such method that permits multiple generalized projections. We introduce a new notion of convex combination and apply it to obtain an extension of the SGP, called the `multidistance SGP' (MSGP) method, that allows for projecton with respect to multiple generalized distances. We conclude with an extension of the MSGP to block-iterative algorithms involving relaxed generalized projections and paracontractive operators.
Oxide interfaces for novel electronic applications

Oxide heterostructures have been shown to exhibit unusual physics and hold the promise of novel electronic applications. We present a set of criteria to select and design interfaces, particularly those that can sustain a high-density two-dimensional electron gas (2DEG). We describe how first-principles calculations can contribute to a qualitative and quantitative understanding, illustrated with the key issue of band alignment. Band offsets determine on which side of the interface the 2DEG will reside, as well as the degree of confinement. We use hybrid density functional calculations to determine the band alignments of a number of complex oxides, considering materials with different types of conduction-band character, polar or nonpolar character and band insulators as well as Mott insulators. We suggest promising materials combinations that could lead to a 2DEG with optimized properties, such as high 2DEG densities and high electron mobilities.
Rhetorical studies and the “new” psychoanalysis: What's the real problem? Or framing the problem of the real

READ MY DESIRE: LACAN AGAINST THE HISTORICISTS. By Joan Copjec. Cambridge and London: The MIT Press, 1994; pp. 272. $30.00; paper $14.00. THE SPOILS OF FREEDOM: PSYCHOANALYSIS AND FEMINISM AFTER THE FALL OF SOCIALISM. By Renata Salecl. London and New York: Routledge, 1994; pp. viii + 167. $59.95; paper $16.95. THE SUBLIME OBJECT OF IDEOLOGY. By Slavoj Žižek. London and New York: Verso, 1989; pp. xvi + 240. $60.00; paper $18.95. UNMARKED: THE POLITICS OF PERFORMANCE. By Peggy Phelan. London and New York: Routledge, 1993; pp. xi + 207. $62.95; paper $17.95.
Reporting Multiple-Group Mean and Covariance Structure Across Occasions With Structural Equation Modeling

Objectives: Using baseline and second wave data, the study evaluated the measurement and structural properties of parenting stress, personal mastery, and economic strain with N = 381 lower income p...
DIAGONALIZING OPERATORS WITH REFLECTION SYMMETRY

Abstract Let U be an operator in a Hilbert space H 0, and let K ⊂ H 0 be a closed and invariant subspace. Suppose there is a period-2 unitary operator J in H 0 such that JUJ=U*, and PJP⩾0, where P denotes the projection of H 0 onto K . We show that there is then a Hilbert space H ( K ), a contractive operator W: K → H ( K ), and a selfadjoint operator S=S(U) in H ( K ) such that W*W=PJP, W has dense range, and SW=WUP. Moreover, given ( K , J) with the stated properties, the system ( H ( K ), W, S) is unique up to unitary equivalence, and subject to the three conditions in the conclusion. We also provide an operator-theoretic model of this structure where U| K is a pure shift of infinite multiplicity, and where we show that ker(W)=0. For that case, we describe the spectrum of the selfadjoint operator S(U) in terms of structural properties of U. In the model, U will be realized as a unitary scaling operator of the form f(x)↦f(cx), c>1, and the spectrum of S(Uc) is then computed in terms of the given number c.
Iron deficiency alters dopamine uptake and response to L‐DOPA injection in Sprague–Dawley rats

Iron deficiency (ID) disrupts brain dopamine (DA) and norepinephrine (NE) metabolism including functioning of monoamine transporters and receptors. We employed caudate microdialysis and no net flux (NNF) in post-weaning rats to determine if ID decreased the extraction fraction (Ed). Five micromolar quinpirole, a dopamine D2 receptor agonist, resulted in 80% decrease in extracellular DA and 45% higher Ed in control animals. The D2 agonist had no effect on Ed in ID animals despite a reduction in basal DA. DAT mRNA levels were reduced by 58% with ID, while DAT protein in ventral midbrain and caudate and membrane associated DAT were also reduced by ID. Carbidopa/l-DOPA was administered to determine if elevated extracellular DA in ID was due to increased release. The DA response to l-DOPA in ID rats was 50% smaller and delayed, whereas the NE response was threefold higher. The caudate concentration of NE was also elevated in ID. Elevated dopamine-β-hydroxylase activity in ID provides a tentative explanation for the increased NE response to l-DOPA. These experiments provide new evidence that ID results in altered synthesis and functioning of DAT and perhaps suggests some compensatory changes in NE metabolism.
The role of home literacy environment in the development of language ability in preschool children from low-income families☆

Abstract The relations between home literacy environment and child language ability were examined for 323 4-year-olds attending Head Start and their mothers or primary caregivers. Overall frequency of shared picture book reading, age of onset of picture book reading, duration of shared picture book reading during one recent day, number of picture books in the home, frequency of child's requests to engage in shared picture book reading, frequency of child's private play with books, frequency of shared trips to the library, frequency of caregiver's private reading, and caregiver's enjoyment of private reading constituted the literacy environment, and were measured using a questionnaire completed by each child's primary caregiver. Using a primary subsample of 236 children, a composite literacy environment score was derived from the literacy environment measures and was correlated with a composite child language measure, derived from two standardized tests of language skills. Depending on the form of regression analysis employed and depending on whether primary caregiver IQ and education were entered into the prediction equations, from 12% to 18.5% of the variance in child language scores was accounted for by home literacy environment. These analyses were cross-validated on a secondary subsample of 87 children with similar results. The strength of the relations between home literacy environment and child language are stronger in this study than in previous research, due to the use of statistically derived aggregate measures of literacy environment. The presence of substantial variability in home literacy environments in low-income families, and the substantial relations between these environments and child language outcomes has important implications for intervention.
The Photochemical Attachment of the O-Glucoside of 3-Hydroxykynurenine to α-Crystallin: A Model for Lenticular Aging

The young human lens contains a small metabolite from tryptophan called the O-glucoside of 3-hydroxykynurenine (3-HKG). Its function is to absorb most radiation between 295 and 400 nm, preventing it from reaching the retina. With age the concentration of this component decreases while the lens crystallins acquire covalently attached chromophores. This study investigates the photochemical attachment of 3-HKG to lens alpha-crystallin. Initial studies showed that alpha-crystallin photolyzed in the presence of 3-HKG developed a fluorescence (emission, 440 nm) and UV-visible spectrum similar to that found in aged human lens proteins. Extensive studies were then performed on the tryptic HPLC maps as monitored by photodiode array and fluorescent detection. Numerous photoproducts with either blue (emission, > 400 nm) or green (emission, > 500 nm) fluorescence were formed in addition to nonfluorescent compounds with absorption maxima above 300 nm. Comparisons were made between these model photoproducts and peptide maps from alpha-crystallin isolated from old human lenses. In terms of retention time and UV-visible spectra at least two of the peptides that appear in the model system are also present in the human samples. It is concluded that one of the aging processes in the human lens is the photochemically induced attachment of 3-HKG to lens proteins.
Response of 21 common beans of diverse origins to two strains of the common bacterial blight pathogen, Xanthomonas campestris pv. phaseoli

Common bacterial blight (CBB) is a severe disease of common bean and the use of resistant cultivars is the most effective control. The objectives were to determine (i) the most appropriate leaf type for CBB evaluation, (ii) the aggressiveness of two bacterial strains, (iii) the presence or absence of SAP6, BC420, and SU91 resistance QTL linked markers, and (iv) the most resistant genotypes. The CBB response in the primary and trifoliolate leaves of 21 genotypes of diverse origins and two checks was evaluated in two greenhouses. Mean trifoliolate leaf score (4.8) was higher than the primary leaf (2.5). The strain Xcp25 (3.2 primary, 5.4 trifoliolate) was more aggressive than ARX8AC (1.7 primary, 4.2 trifoliolate). Andean ‘Montcalm’ with SAP6 QTL was intermediate (6.0) to ARX8AC and susceptible (8.3) to Xcp25 in the trifoliolate leaf. New Andean RCS52-2, RCS53-3, and RCS63-5B with BC420 and SU91, and 08SH840 with SAP6 and SU91 QTL were intermediate (3.5–6.2) to both strains. But, Middle American VAX 3, VAX 4, and VAX 6 with SAP6 and SU91 QTL were resistant (2.3–2.5) to ARX8AC and intermediate to Xcp25 (3.4–6.5) in the trifoliolate leaf. Further efforts are required to pyramid higher levels of resistance from across Phaseolus species and introgressed in Andean common bean.
Effects of dithiocarbamate and 8-hydroxyquinoline additions on algal uptake of ambient copper and nickel in South San Francisco Bay water

The addition of synthetic organic ligands such as diethyldithiocarbamate (DDC) and 8-hydroxyquinoline (Ox) to the dissolved fraction (<0.2 μm) of South San Francisco Bay water facilitated the transport of ambient Cu and Ni into phytoplankton cells. The uptake mechanism is diffusion of the lipophilic organic Cu(DDC)2 0 and Cu(Ox)2 0 complexes (and corresponding Ni complexes) across the plasma membrane. Short-term uptake experiments were carried out using a coastal diatom,Thalassiosira weissflogii, and resulted in rapid uptake rates and high cellular concentrations of the metal relative to the bay water control. Steady-state conditions between the solution and cellular Cu concentrations occurred within 10 min for a 4 μM addition of DDC and after 3 h for a 100 μM addition of Ox. Steady-state cellular Cu concentrations were over 10 times and 6 times greater, for DDC and Ox treatments, than in the bay water controls. Steady-state cellular Ni concentrations were attained within 10 min for both ligand additions and were more than 6 times and 2 times greater than in the absence of the added ligands. Using this bioassay, we were also able to gain insight into the character of the background organic Cu complexes in South Bay. Our results suggest that the natural organic Cu complexes are relatively hydrophilic in character and do not appear to be directly assimilated across the plasmalemma.