cssi/SciSciGPT-SciSciNet huggingface dataset:
The Mechanism of ATP-Dependent Primer-Template Recognition by a Clamp Loader Complex

Clamp loaders load sliding clamps onto primer-template DNA. The structure of the E. coli clamp loader bound to DNA reveals the formation of an ATP-dependent spiral of ATPase domains that tracks only the template strand, allowing recognition of both RNA and DNA primers. Unlike hexameric helicases, in which DNA translocation requires distinct conformations of the ATPase domains, the clamp loader spiral is symmetric and is set up to trigger release upon DNA recognition. Specificity for primed DNA arises from blockage of the end of the primer and accommodation of the emerging template along a surface groove. A related structure reveals how the psi protein, essential for coupling the clamp loader to single-stranded DNA-binding protein (SSB), binds to the clamp loader. By stabilizing a conformation of the clamp loader that is consistent with the ATPase spiral observed upon DNA binding, psi binding promotes the clamp-loading activity of the complex.
Supramolecular asymmetric induction in dinuclear triple-stranded helicates.

Supramolecular chiral induction has been observed in five dinuclear triple-stranded helicates composed entirely of achiral components. Three different chiral cations were found to be very effective at inducing high levels of enantiomeric enrichment in racemic mixtures of the helicates. The mechanism of intermolecular chiral induction in one cation−helicate pair, s-nic/K6[Ga2L13], has been elucidated through circular dichroism spectroscopy, X-ray crystallography, and one and two-dimensional NMR spectroscopy (s-nic = N-methyl-s-nicotinium, H4L1 = 1,4-bis(2‘,3‘-dihydroxybenzamido)phenylene).
The Price of a Warranty: The Case for Refrigerators

Hedonic price analysis was used to estimate the implicit market prices of the physical attributes and warranty provisions of refrigerators. Estimates were made of the implicit market prices of 2 warranty provisions, 6 physical characteristics and 13 brands using 1975 data on 156 models. The estimates were made of the implicit market prices of an additional 4 years and 9 years warranty coverage beyond the typical 1 year coverage. The results suggest that the implicit price of such additional warranty coverage exceeds (a) the cost of a service contract for a similar period, and (b) estimates of the present value of the expected cost of repairs.
End of Inclosure

This paper briefly defends theses in Beall 2014 against objections advanced in Weber et al. 2014. The second part of the paper both defends and fortifies an objection to the �inclosure� argument for glut theory, spelling an end to the inclosure strategy (or at least its application to the sorites).
Autogamy in the American strain of witchweed, striga asiatica (scrophulariaceae)

American plants ofStriga asiatica (witchweed), a serious pathogen of corn and other grains that was accidentally introduced to the Carolinas in the 1950’s, exhibit a form of autogamy in which fertilization occurs before the corolla opens. Pollen is shed on the stigma while the flowers are still in bud. Pollen grains germinate immediately and by the time the corolla is open fertilization has occurred. Examination of a native population of the same species in Nigeria revealed no autogamy.
Syringe exchange in the United States: a national level economic evaluation of hypothetical increases in investment

To examine whether increasing investment in needle/syringe exchange programs (NSPs) in the US would be cost-effective for HIV prevention, we modeled HIV incidence in hypothetical cases with higher NSP syringe supply than current levels, and estimated number of infections averted, cost per infection averted, treatment costs saved, and financial return on investment. We modified Pinkerton’s model, which was an adaptation of Kaplan’s simplified needle circulation theory model, to compare different syringe supply levels, account for syringes from non-NSP sources, and reflect reduction in syringe sharing and contamination. With an annual $10 to $50 million funding increase, 194–816 HIV infections would be averted (cost per infection averted $51,601–$61,302). Contrasted with HIV treatment cost savings alone, the rate of financial return on investment would be 7.58–6.38. Main and sensitivity analyses strongly suggest that it would be cost-saving for the US to invest in syringe exchange expansion.
Optical flow object detection, motion estimation, and tracking on moving vehicles using wavelet decompositions

Optical flow-based tracking methods offer the promise of precise, accurate, and reliable analysis of motion, but they suffer from several challenges such as elimination of background movement, estimation of flow velocity, and optimal feature selection. Wavelet approximations can offer similar benefits and retain spatial information at coarser scales, while optical flow estimation increases with the reduction of finer details of moving objects. Optical flow methods often suffer from significant computational overload. In this study, we have investigated the necessary processing steps to increase detection and estimation accuracy, while effectively reducing computation time through the reduction of the image frame size. We have implemented an object tracking algorithm using the optical flow calculated from a phase change between representative coarse wavelet coefficients in subsequent image frames. We have also compared phasebased optical flow with two versions of intensity-based optical flow to determine which method produces superior results under specific operational conditions. The investigation demonstrates the feasibility of using phase-based optical flow with wavelet approximations for object detection and tracking of low resolution aerial vehicles. We also demonstrate that this method can work in tandem with feature-based tracking methods to increase tracking accuracy.
Central distribution and three-dimensional arrangement of fin chromatophore motoneurons in the cuttlefish Sepia officinalis

Cephalopod body patterning is a most complex invertebrate behavior. Generated primarily by pigment-containing chromatophore organs, this behavior enables rapid alteration of body coloration as a result of direct innervation of chromatophores by motoneurons. This study focuses on location and arrangement of fin chromatophore motoneurons in the cuttlefish Sepia and investigates the possibility of central topography. Retrograde labeling of topographically arranged fin nerve branches in the periphery revealed the posterior subesophageal mass (PSEM) of the brain as the primary location of fin chromatophore motoneurons; within this region, most cells were located in the posterior chromatophore and fin lobes. Additionally, a small percentage of labeled motoneurons occurred in the anterior subesophageal mass and the stellate ganglia. Data from three-dimensional reconstructions of PSEMs showed the arrangement of labeled motoneurons within individual lobes; these data suggest no obvious topographic arrangement. Further, electrical stimulation of the PSEM generated chromatophore activity on the fin and mantle. These stimulation results, coupled with the retrograde labeling, suggest that chromatophore motoneurons are located across multiple PSEM lobes.
The effects of castration and treatment with testosterone on the biliary excretion of (3H)aldosterone in rats.

The rate of excretion of aldosterone radiometabolites into the bile after bile duct cannulation, and the intravenous injection of [3H]aldosterone, was demonstrated to be markedly increased in male rats following castration. In 1 h, 72% of the injected 3H-radioactivity was excreted in the bile of castrated male rats compared with 26% in the intact male control rats. Castration of the males led to the increased biliary excretion of aldosterone metabolites and the elimination of the sexdependence of this process in rats. The ovariectomy of female rats did not substantially increase the rate of excretion of aldosterone metabolites via the bile. Castrated male rats treated with testosterone excreted aldosterone metabolites into the bile at a slower rate. A similar treatment of ovariectomized female rats with testosterone also significantly slowed the rate of biliary excretion of the aldosterone metabolites. These findings suggest that the presence of androgens plays an important role in regulating the routes o...
Bimolecular infrared radiative association reactions. Attachment of Li+ to carbonyl compounds in the gas phase

Abstract Direct clustering of Li + with (C 2 H 5 ) 2 CO, CH 3 COC 2 H 5 , (CD 3 ) 2 CO, CH 3 CHO and H 2 CO is examined in the gas phase by ion cyclotron resonance spectroscopy. Initial interaction of Li + with the carbonyl compound leads to formation of a vibrationally excited adduct which can be stabilized by energy loss in collisional or infrared radiative processes. At pressures where the time between collisions exceeds 100 ms the dominant stabilization mechanism is assumed to be infrared emission; calculations of radiative rates are presented. Calculated rates for Li + attachment at low pressures are found to be in good agreement with experiment. Implications of bimolecular infrared radiative association reactions for molecular synthesis in interstellar space are discussed.
Molecular modeling in food research: technology and techniques

Abstract The development of structure-function relationships is essential to the effective use of biotechnology for solving problems in food science and technology. The introduction of more powerful computers, together with the increased availability of efficient molecular modeling software will enable the study of such relationships. In this review, we present the most important techniques used in the modeling of small molecules, proteins, nucleic acids and polysaccharides. A brief description of the application of experimental techniques for structure determination, such as X-ray crystallography, two-dimensional nuclear magnetic resonance spectroscopy, circular dichroism spectroscopy and Fourier transform infrared spectroscopy is provided, with particular emphasis on their relevance to molecular modeling. Various techniques for determining the minimum conformational potential energy, ranging from rigorous molecular orbital methods based on quantum mechanics to approximate molecular mechanics methods based on force-field calculations, are described; the selection of appropriate methods to study particular sizes and types of molecules and molecular motions is also presented.
Surface structural transitions during tin segregation to the surface of a (100) iron crystal

Abstract A study of the segregation of Sn to the (100) surface of an Fe-1.25 at% Sn crystal has been carried out by means of AES, LEED, and UPS using synchrotron radiation. The room temperature LEED patterns transformed gradually with increasing Sn coverage from p(1 × 1) for the clean surface to c(2 × 2) at a half-monolayer, then to p(1 × 1) at one monolayer, and finally to p(2 × 2) at the maximum observed coverage of 1.2 monolayers. The latter was the ultimate, presumably equilibrium, coverage achieved at 500 °C; above that temperature the equilibrium coverage decreased linearly up to 650 °C, above which evaporation occurred. The final LEED pattern transition was accompanied by a rapid increase in the Sn 4d binding energy toward the value associated with pure Sn and also a broadening of the Sn4d 5 2 peak. At the ultimate maximum coverage of 1.2 monolayers the LEED pattern transformed gradually and reversibly from p(2 × 2) to c(2 × 2) upon heating above about 300 ° C. A further gradual and reversible transformation to p(1 × 1) occurred upon heating above about 570 °C and was presumably associated with the reduction in equilibrium coverage above 500 °C. These results differ in several respects from a contemporaneous study of a similar alloy, and they raise interesting questions about the nature of the equilibrium surface in this intriguing alloy system.
Simulations of monomeric amyloid β-peptide (1-40) with varying solution conditions and oxidation state of Met35: implications for aggregation.

Abstract The amyloid β-peptide (Aβ) is a 40–42 residue peptide that is the principal toxic species in Alzheimer’s disease (AD). The oxidation of methionine-35 (Met35) to the sulfoxide form (Met35 ox ) has been identified as potential modulator of Aβ aggregation. The role Met35 ox plays in Aβ neurotoxicity differs among experimental studies, which may be due to inconsistent solution conditions (pH, buffer, temperature). We applied atomistic molecular dynamics (MD) simulations as a means to probe the dynamics of the monomeric 40-residue alloform of Aβ (Aβ 40 ) containing Met35 or Met35 ox in an effort to resolve the conflicting experimental results. We found that Met35 oxidation decreases the β-strand content of the C-terminal hydrophobic region (residues 29–40), with a specific effect on the secondary structure of residues 33–35, thus potentially impeding aggregation. Further, there is an important interplay between oxidation state and solution conditions, with pH and salt concentration augmenting the effects of oxidation. The results presented here serve to rationalize the conflicting results seen in experimental studies and provide a fundamental biophysical characterization of monomeric Aβ 40 dynamics in both reduced and oxidized forms, providing insight into the biochemical mechanism of Aβ 40 and oxidative stress related to AD.
Human renal clear cell carcinoma: Establishment and characterization of a new cell line (G-2101)

A human cell line has been established from a renal adenocarcinoma rib metastasis of a 58-y-old male. This cell line has been maintained in continuous culture for 20 mo. through more than 50 passages. It displays simulataneous expression of the intermediate filaments cytokeratin and vimentin. Flow cytometric analysis of DNA content reveals a major hyperdiploid population.
The Walker Art Center + The Tyrone Guthrie Theater, Minneapolis: Two Views

(2008). The Walker Art Center + the Tyrone Guthrie Theater, Minneapolis: Two Views. Journal of Architectural Education: Vol. 61, No. 4, pp. 131-135.
Compensatory adaptations of skeletal muscle fiber types to a long-term functional overload☆

Abstract We investigated selected histochemical and histometrical characteristics of the heterogeneous fiber types of rat skeletal muscle following long-term compensatory muscle growth. Sixty days following surgical removal of the synergistic gastrocnemius muscle, the compensated ipsilateral plantaris and soleus muscles and the corresponding control muscles from the contralateral leg were excised and stained histochemically for myofibrillar ATPase and DPNH-diaphorase activities. The number of fibers per cross-section was determined by a direct count from transverse sections taken from the midportion of the muscles. Fiber area was determined by direct planimetry. The plantaris and soleus muscles hypertrophied 103% and 45%, respectively, within 60 days. Compensatory hypertrophy of the plantaris muscle was accompanied by a significant but disproportionate increase in the cross-sectional areas of the three muscle fiber types. There was an approximate 4-fold increase in the number of slow-twitch-oxidative (SO) fibers observed per transverse section. The hypertrophied plantaris muscle exhibited a significantly greater number of fibers per cross-section (29%) than the respective control muscle. The compensated soleus muscle consisted of nearly 100% SO fibers compared to 83% for the control soleus muscle.
Religious Coping, Positive Aspects of Caregiving, and Social Support Among Alzheimer’s Disease Caregivers

The purpose of this study was to investigate the relationships between religious coping, positive aspects of caregiving, social support, burden, and depression in Alzheimer’s caregiving. Using data from the Resources for Enhancing Alzheimer’s Caregiver Health (REACH) II study, results based on structural equation modeling analysis provided some support for the hypothesized path model. Positive religious coping was positively associated with positive aspects of caregiving and social support, which was negatively associated with burden and depression. Positive religious coping was found to have positive effects, yet negative religious coping had no effects on any outcomes. The findings suggest developing and maintaining religiosity plays an important role in enhancing positive aspects of caregiving and social support and thus in decreasing caregiver burden and depression.
Editor’s Notes - Introduction to the Inaugural Issue of the Journal of Outdoor Recreation, Education, and Leadership

It's my honor and pleasure to introduce you to Volume 1, Issue 1 of the Journal of Outdoor Recreation, Education, and Leadership (JOREL)! As many of you may know, the JOREL is the only peerreviewed journal published in the United States with a specific focus on the areas of outdoor recreation, education, and leadership. It's taken almost 10 years for the JOREL to finally make it to publication. What started out as an idea in 2001 is finally here! It took the efforts and vision of a number of individuals from the Association of Outdoor Recreation and Education (AORE) Research and Publications Committee over the years to make this publication possible. Individuals from the Wilderness Education Association (WEA) joined the effort in 2007 and ultimately, AORE, WEA, and the Western Kentucky University Research Foundation created a partnership to make this project a reality. I would like to extend a well-deserved thank you to each of you for your foresight and commitment to this endeavor.
An analytical system based on a compact flow cytometer for DNA fragment sizing and single-molecule detection.

Background Previous reports have demonstrated accurate DNA fragment sizing of linear DNA fragments, from 564 to ≈4 × 105 bp, in a flow system. B-phycoerythrin (B-PE), commonly used in conventional cytometric applications that require high-sensitivity, was the first fluorophore detected in flow at the single-molecule level. Methods Dilute solutions of stained DNA fragments or B-PE were analyzed in a simplified, compact flow system, with enhanced performance and lower cost, utilizing a solid-state laser and a single-photon sensing avalanche photodiode detector (SSAPD). Extensive data processing and display software, developed specifically for the photon-counting data stream, extracts correlated height, width, and area features from bursts of photons due to discrete molecules passing through the sensing region in the flow channel. Results DNA fragment sizing in flow has now been demonstrated for SYTOX-orange–stained fragments ranging in size over 3.4 orders of magnitude, from 125 to 5 × 105 bp. For Lambda bacteriophage DNA (λ DNA; 48.5 kbp) a CV of 1.2 % has been achieved. Analysis of a femtomolar B-PE solution demonstrates that the bursts of photons from individual molecules can be baseline-resolved with 0.5 mW of laser power at a signal to noise ratio (SNR) of ≈30, with ≈100 photons detected from each molecule. Conclusions A compact, low-power, high-sensitivity system detects DNA fragments as small as 125 bp or individual B-PE molecules in a flowing liquid stream. Demonstrated linearity, sensitivity, and resolution indicate that <1.0 mW of laser power is optimal, permitting further miniaturization of the system and additional cost reduction. Comprehensive analytical software exploits the standard cytometric paradigm of multiple 2D graphs and gating to extract features from classes of individually analyzed biomolecules. This complete system is thus poised to engage high-sensitivity applications not amenable to conventional flow cytometric instrumentation. © 2004 Wiley-Liss, Inc.
Three-beam water vapor sensor system for combustion diagnostics using a 1390-nm tunable diode laser

H 2 O (v) is an important species in combustion and hypersonic flow measurements because it is a primary combustion product. Measurements of water vapor can be used to determine performance parameters, such as extent and efficiency of combustion in propulsion and aerodynamics facilities. Water vapor concentration measurement in these high- temperature hypervelocity combustion conditions requires very high sensitivity and fast time response. A three-beam diode laser H 2 O (v) measurement system for nonintrusive combustion diagnostics has been developed at NASA Langley Research Center and successfully tested and installed at GASL NASA HYPULSE facility for routine operation. The system was built using both direct laser absorption spectroscopy and frequency modulation laser spectroscopy. The output beam from a distributed feedback (DFB) InGaAsP diode laser (emitting around 1.39 micrometers ) is split into three equal-powered equal-distanced parallel beams with separation of 9 mm. With three beams, we are able to obtain water vapor number densities at three locations. Frequency modulation spectroscopy technique is used to achieve high detection sensitivity. The diode laser is modulated at radio frequency (RF), while the wavelength of the diode laser is tuned to scan over a strong waver vapor absorption line. The detected RF signal is then demodulated at the fundamental frequency of the modulation (one-F demodulation). A working model and a computer software code have been developed for data process and data analysis. Water vapor number density measurements are achieved with consideration of temperature dependency. Experimental results and data analysis will be presented.
Subcellular Localization, Aggregation State, and Catalytic Activity of Microsomal P450 Cytochromes Modified in the NH2-Terminal Region and Expressed in Escherichia coli

Abstract This laboratory previously expressed cDNAs encoding rabbit liver cytochrome P450 2E1. (the ethanol-inducible isoform) and the corresponding protein lacking amino acids 3-29, a proposed membrane anchor, in Escherichia coli. Unexpectedly, the shortened protein, like the full-length form, was found to be predominantly located in the bacterial inner membrane rather than the cytosol and to have full catalytic activity. Additional proteins with alterations in the NH2-terminal region of P450 2E1 or P450 2B4 (the phenobarbital-inducible isoform) were similarly expressed, and it was concluded that such modifications can change the cytochrome to an increased cytosolic localization and that the first two hydrophobic segments are not uniquely involved in attachment to the bacterial membrane (Pernecky et al., 1993, Proc. Natl. Acad. Sci. USA 90, 2651-2655). In the present study, three chimeric cytochromes were produced to determine the effect on subcellular localization: 2E1:2B4, in which the first 17 residues of 2E1 (Δ3-29) replaced the corresponding 17 residues in 2B4 (Δ2-27), and BM-3:2B4 and BM-3:2E1, in which the first 19 residues of P450BM-3 replaced the first 17 in 2B4 (Δ2-27) and 2E1 (Δ3-29), respectively. Of the total cytochrome expressed, the localization in the E. coli cytosol was about 60, 70, and 80% for the respective chimeras, with 80% being the highest for any P450 we have examined. A plot of the extent of membrane binding versus hydropathy of the NH2-terminal region showed that the terminal sequence strongly influences the subcellular distribution and that a group of 2E1 proteins and a group of 2B4 proteins each have other regions that characteristically determine the extent of membrane attachment. The role of the NH2-terminal region in the high level of aggregation of purified full-length P450 is indicated by the finding that the multimeric state of 2E1 or 2B4 is unaffected by sodium cholate at concentrations that convert 2E1 (Δ3-29) or 2B4 (Δ2-27) to the monomeric state. In contrast to our earlier experience with P450 2E1, purified P450 2B4 (Δ2-27) has on the average only about half the activity of full-length 2B4 with substrates that undergo oxidative dealkylation or oxygenation at a hydroxyl group.
Tin in a chondritic interplanetary dust particle

Submicron platey Sn-rich grains are present in chondritic porous interplanetary dust particle (IDP) W7029 A and it is the second occurrence of a tin mineral in a stratospheric micrometeorite. Selected Area Electron Diffraction data for the Sn-rich grains match with Sn2O3 and Sn3O4. The oxide(s) may have formed in the solar nebula when tin metal catalytically supported reduction of CO or during flash heating on atmospheric entry of the IDP. The presence of tin is consistent with enrichments for other volatile trace elements in chondritic IDPs and may signal an emerging trend toward nonchondritic volatile element abundances in chondritic IDPs. The observation confirms small-scale mineralogical heterogeneity in fine-grained chondritic porous interplanetary dust.
Defect Microstructures and Deformation Mechanisms in Irradiated Austenitic Stainless Steels

Microstructural evolution and deformation behavior of austenitic stainless steels are evaluated for neutron, heavy-ion and proton irradiated materials. Radiation hardening in austenitic stainless steels is shown to result from the evolution of small interstitial dislocation loops during lightwater-reactor (LWR) irradiation. Available data on stainless steels irradiated under LWR conditions have been analyzed and microstructural characteristics assessed for the critical fluence range (0.5 to 10 dpa) where irradiation-assisted stress corrosion cracking susceptibility is observed. Heavy-ion and proton irradiations are used to produce similar defect microstructures enabling the investigation of hardening and deformation mechanisms. Scanning electron, atomic force and transmission electron microscopies are employed to examine tensile test strain rate and temperature effects on deformation characteristics. Dislocation loop microstructures are found to promote inhomogeneous planar deformation within the matrix and regularly spaced steps at the surface during plastic deformation. Twinning is the dominant deformation mechanism at rapid strain rates and at low temperatures, while dislocation channeling is favored at slower strain rates and at higher temperatures. Both mechanisms produce highly localized deformation and large surface slip steps. Channeling, in particular, is capable of creating extensive dislocation pileups and high stresses at internal grain boundaries which may promote intergranular cracking.
Novel inter-series hybrids in Solanum, section Petota

Sexual hybrids between distantly related Solanum species can undergo endosperm failure, a post-zygotic barrier in inter-species hybridizations. This barrier is explained by the endosperm balance number (EBN) hypothesis, which states that parents must have corresponding EBNs for viable seed formation. Tests for inter-crossability were made involving the Mexican species Solanum pinnatisectum Dunal. (series Pinnatisecta, ApiApi, 1EBN), autotetraploids of this species, Solanum verrucosum Schlechtd. (series Tuberosa, AA, 2EBN), haploids (2x, 2EBN) of the South American S. tuberosum L. (series Tuberosa, A1A1A2A2, 4EBN), and F2 haploid-species hybrids with South American species (AA, 2EBN) S. berthaultii Hawkes, S. sparsipilum (Bitter.) Juz. and Bukasov and S. chacoense Bitter. The development of hybrid endosperms was investigated for these combinations by confocal microscopy with regard to cell-division timing and tissue collapse. Novel sexual diploid (AApi) and triploid (AApiApi) inter-series hybrids were generated from S. verrucosum × S. pinnatisectum crosses by using post-pollination applications of auxin. F1 embryos were rescued in vitro. The hybrid status of recovered plants was verified by microsatellite marker analysis, and the ploidy was determined by chromosome counting. The application of phytohormones in inter-ploidy S. pinnatisectum × S. tuberosum crosses, however, did not delay endosperm collapse, and embryos were not formed. Other diploid, 1EBN species tested in remote hybridizations with Group Tuberosum were S. cardiophyllum Lindl., S. trifidum Correll, and S. tarnii Hawkes and Hjert., series Pinnatisecta, and S. bulbocastanum Dunal., series Bulbocastana. Based on the analysis of post-zygotic reproductive barriers among isolated species of section Petota, we propose strategies to overcome such incompatibilities.
Magnesium deficiency-induced cardiomyopathy: protection by vitamin E.

Abstract Syrian male hamsters weighing 80–100g were placed on either a magnesium deficient diet (MgD) or an identical diet supplemented with 100 mmols/Kg MgCl. Animals from each group received vitamin E 10, 15, and 25mg three-week slow release pellets, as subcutaneous implants. The animals were sacrificed after 14 days and their hearts isolated for morphological analysis. H&E stained sections were examined by a computer image analysis system for a morphometric determination of the severity of myocardial injury. Vitamin E significantly (p
Surface diffusion activation energy determination using ion beam microtexturing

The activation energy for impurity atom (adatom) surface diffusion can be determined from the temperature dependence of the spacing of sputter cones. These cones are formed on the surface during sputtering while simultaneously adding impurities. The impurities form clusters by means of surface diffusion, and these clusters in turn initiate cone formation. Values are given for the surface diffusion activation energies for various materials on polycrystalline Cu, Al, Pb, Au, and Ni. The values for different impurity species on each of these substrates are approximately independent of impurity species within the experimental uncertainty, suggesting the absence of strong chemical bonding effects on the diffusion.
Obstacles to Population Control

Davis' article "Population policy: Will current programs succeed?" (10 Nov., p. 730) is excellent and I can only elaborate on one point. He wrote: "Support and encouragement of research on population policy other than family planning is negligible. It is precisely this blocking of alternative thinking and experimentation that makes the emphasis on family planning a major obstacle to population control." This statement minimizes the problem.
Phase II study of dasatinib in patients with previously treated malignant mesothelioma (Cancer and Leukemia Group B 30601): a brief report

Introduction We conducted a phase II trial of dasatinib in malignant mesothelioma (MM) patients to evaluate its toxicity and efficacy as a second-line treatment. Methods Patients with unresectable MM and no symptomatic effusions were given dasatinib 70 mg twice daily as part of a 28-day cycle. We also measured plasma vascular endothelial growth factor and platelet-derived growth factor b and colony stimulating factor 1 (CSF-1) and mesothelin-related protein at baseline and during therapy. Results Forty-six patients were enrolled in this study. Fifty percent of the first 12 patients enrolled experienced ≥grade 3 treatment-related adverse events, and therefore, the starting dose was reduced to 50 mg twice daily. Grade 3 and 4 toxicities included fatigue (11%) and pleural effusion (9%). The overall disease control rate was 32.6%, and progression-free survival at 24 weeks was 23% (95% confidence interval: 13.5–40.0%). Survival was markedly longer in patients with lower pretreatment CSF-1 levels and in patients whose CSF-1 levels decreased from baseline during therapy. Discussion Single-agent dasatinib has no activity in MM and is associated with pulmonary toxicities that prohibit its use in an unselected MM population.
Synthesis and Reactivity of New Pyrazolyl-Functionalized Potassium Silanides

The pyrazolyl-functionalized oligosilanes Si(SiMe2PzR)4 (2a R = tBu; 2b R = iPr) were prepared by the reaction of 3-R-pyrazole (R = iPr, tBu) with Si(SiMe2Cl)4 in the presence of NEt3. By treatment with tBuOK and 18-crown-6 in THF, 2a, b were converted into the new potassium silanides (PzRMe2Si)3SiK(18-crown-6) (3a R = tBu; 3b R = iPr), respectively. Upon adding W(CO)6 to THF solutions of 3a, b the tungsten complexes [(PzRMe2Si)3SiW(CO)5]K(18-crown-6) (4a R = tBu; 4b R = iPr) were readily formed, whereas upon adding MgBr2 fragmentation occurs leading to the formation of [(PzRMe2Si)2Si-SiMe2]25.
Deliberating about justice: The role of justice in the practical deliberations of states

Whether it is the obstruction of aid by a military junta, complicity in the perpetration of genocide, or the use of violence to cling to power, states are often confronted with reasons for action that are based on matters of justice internal to another state. However, the practical deliberations of states are taken by many to be governed by a normative principle that precludes states from considering reasons for action that would require one state to interfere with the internal affairs of another state. I argue that such a preclusive principle cannot be morally justified, and that the practical deliberations of states ought instead to be governed by a rebuttable presumption in favor of noninterference. The argument proceeds in three steps. First, I explicate various arguments for the preclusive principle. Second, I argue that none of the arguments considered succeed. Lastly, I contend that the practical deliberations of states should be governed by a rebuttable presumption in favor of noninterference.
Enzymatic Changes in Alveolar Macrophages of Rats Exposed to Lead and Nickel by Inhalation

In previous inhalation studies, rats exposed to aerosol concentrations of lead oxide (Pb2O3), 150 μg/m3; lead chloride (PbCl2), 100 μg/m3; nickel oxide (NiO), 120 μg/m3; and nickel chloride (NiCl2), 109 μg/m3; significant changes were observed in the lungs and alveolar macrophages. In this study the hydroiytic enzymes, acetylesterase, acid and alkaline phos-phatases, lysozyme, and beta-glucuronidase, in alveolar macrophages and lung washout fluid from rats subjected to the inhalation of the lead and nickel aerosols were examined. Washed alveolar macrophages from animals exposed to lead and nickel aerosols were found to contain reduced quantities of the various hydrolytic enzymes (except for acetylesterase) when compared with those from control rats. On the other hand, a significant increase in enzymatic activity was noted in lung washout fluid from exposed animals. The functional efficiency of macrophages, relative enzyme changes, and the mechanism of action of metals are discussed. It is important to not...
Transformation of image-signal-dependent noise into image-signal-independent noise

A point transformation, the normalizing transform, is presented, which, when applied to a measured noisy image, renders its noise signal independent. The transform is suitable for arbitary noise-to-signal dependence. We demonstrate its applicability and its limitations by using, as an example, noisy signals that belong to a family of gamma-distributed random variables with power-law variance-to-mean dependence. Its normalizing and variance-stabilizing properties are studied.
Alcohol use and cerebral white matter compromise in adolescence

Alcohol use is typically initiated during adolescence, a period known to be critical in neurodevelopment. The adolescent brain may be particularly susceptible to the harmful effects of alcohol. While the cognitive deficits associated with alcohol use during adolescence have been well-documented, the neural substrates underlying these effects remain inadequately understood. Cerebral white matter has been suggested as a primary site of alcohol-related damage and diffusion tensor imaging (DTI) allows for the quantification of white matter integrity in vivo. This review summarizes results from both cross-sectional and longitudinal studies employing DTI that indicate that white matter tracts, particularly those thought to be involved in executive functioning, continue to develop throughout adolescence and into adulthood. Numerous DTI studies reveal a positive correlation between white matter integrity and neurocognitive performance and, in adults, the detrimental effects of prolonged alcohol-dependence on white matter integrity. We provide a comprehensive review of the DTI studies exploring the relationship between alcohol use and white matter integrity in adolescents. Results from most of these studies suggest that alcohol use is associated with reduced white matter integrity, particularly in the superior longitudinal fasciculus (SLF), and some evidence suggests that this relationship may be influenced by sex. We conclude by highlighting confounds and limitations of the available research and suggesting directions for future research.
Changes in the use of postacute care during the initial Medicare payment reforms.

Medicare postacute care (PAC) services provide recuperative or rehabilitative services to patients discharged from acute-care hospitals. As hospital length of stays shortened considerably after the hospital prospective payment system implemented in 1983, these services became a critical transition in the continuum of care for elderly patients. These services—mainly skilled nursing facilities (SNFs), inpatient rehabilitation units or hospitals (IRFs), and home health agencies (HHAs)—were the fastest growing components of Medicare spending in the 1990s, with an average annual growth rate of 34 percent (Medicare Payment Advisory Commission [U.S.] 2001). In response to such dramatic increases and with widespread administrative and legislative concerns about possible fraud and abuse by providers, both regulators and legislators devoted considerable attention to PAC services in the mid-1990s. Regulators aggressively pursued potential fraud and abuse, particularly in HHAs, whereas Congress mandated payment reforms in the Balanced Budget Act of 1997. These regulatory compliance initiatives and the sequential implementation of payment reforms had the potential to lead to reimbursement-driven substitution between settings without regard to the appropriateness of care. Nevertheless, most studies of PAC payment reforms have focused on each setting in isolation, with little investigation of how they might be used interchangeably. To our knowledge, no analyses have simultaneously considered all three major PAC settings across years and used multivariate methods to control for variables affecting their use. Using such an approach, we examined how usage shifted among PAC settings as payment reforms introduced new financial incentives.
Enhancement of pulsatile growth hormone secretion by continuous infusion of a growth hormone-releasing peptide mimetic, L-692,429, in older adults--a clinical research center study.

L-692,429 ([L]) is a GH-releasing peptide mimetic that stimulates GH secretion when administered acutely. To determine the effect of its continuous administration, six older adults (four men and two women, aged 64-82 yr) received i.v. transfusions of 1) saline for 24 h (control), 2) [L] (0.05 mg/kg.h) for 24 h (low dose), and 3) [L] (0.1 mg/kg.h) for 12 h, then saline for 12 h (high dose), followed on all admissions by saline for 2.5 h. GHRH (1 microgram/kg, i.v.) was given 30 min before the end of each 24-h treatment. Blood was collected every 10 min for GH measurement, and GH secretion was assessed by deconvolution analysis. Pulsatile GH secretion continued throughout both [L] infusions. During the first 12 h (when comparison of both doses was possible), [L] exerted a dose-dependent stimulatory effect on mean GH concentrations, from 0.6 +/- 0.1 (control, mean +/- SE), to 1.2 +/- 0.2 (low dose [L]) and 2.3 +/- 0.5 microgram/L (high dose [L]; P < 0.05, high dose vs. control), and on calculated GH secretor...
Lipids and lipidomics in brain injury and diseases.

Lipidomics is systems-level analysis and characterization of lipids and their interacting moieties. The amount of information in the genomic and proteomic fields is greater than that in the lipidomics field, because of the complex nature of lipids and the limitations of tools for analysis. The main innovation during recent years that has spurred advances in lipid analysis has been the development of new mass spectroscopic techniques, particularly the “soft ionization” techniques electrospray ionization and matrix-assisted laser desorption/ionization. Lipid metabolism may be of particular importance for the central nervous system, as it has a high concentration of lipids. The crucial role of lipids in cell signaling and tissue physiology is demonstrated by the many neurological disorders, including bipolar disorders and schizophrenia, and neurodegenerative diseases such as Alzheimer's, Parkinson's, and Niemann-Pick diseases, that involve deregulated lipid metabolism. Altered lipid metabolism is also believed to contribute to cerebral ischemic (stroke) injury. Lipidomics will provide a molecular signature to a certain pathway or a disease condition. Lipidomic analyses (characterizing complex mixtures of lipids and identifying previously unknown changes in lipid metabolism) together with RNA silencing, using small interfering RNA (siRNA), may provide powerful tools to elucidate the specific roles of lipid intermediates in cell signaling and open new opportunities for drug development.
Infrared optical properties of aged porous GaAs

Aging properties of porous GaAs were investigated nondestructively using variable angle of incidence infrared spectroscopic ellipsometry. In addition to the thickness and volume porosity, properties of the solid part of the porous material are investigated in terms of the long-wavelength dielectric function and chemical composition. The high sensitivity is employed to detect and identify infrared resonant absorptions related to different vibration modes of cubic and amorphous As2O3. Resonances centered at 333.3, 480, 785.8, 838, and 1045.5 cm−1 are from cubic As2O3, whereas resonances centered at 350, 490, and 808.5 cm−1 are from amorphous As2O3.
The structure of augmenter of liver regeneration crystallized in the presence of 50 mM CdCl2 reveals a novel Cd2Cl4O6 cluster that aids in crystal packing.

The crystal structure of the protein augmenter of liver regeneration containing a 14-residue hexahistidine purification tag (hsALR) has been determined to 2.4 A resolution by Cd-SAD using a highly redundant data set collected on a rotating-anode home X-ray source and processed in 1998. The hsALR crystal structure is a tetramer composed of two homodimers bridged by a novel Cd2Cl4O6 cluster via binding to the side-chain carboxylate groups of two solvent-exposed aspartic acid residues. A comparison with the native sALR tetramer shows that the cluster dramatically changes the hsALR dimer–dimer interface, which can now better accommodate the extra 14 N-terminal residues associated with the purification tag. The refined 2.4 A resolution structure is in good agreement with both the X-ray data (Rcryst of 0.165, Rfree of 0.211) and the expected stereochemistry (r.m.s. deviations from ideality for bond lengths and bond angles of 0.007 A and 1.15°, respectively).
Effect of acute and daily cocaine treatment on extracellular dopamine in the nucleus accumbens.

The behavioral stimulant effect of peripheral cocaine injection into rats is augmented following daily adminstration. In vivo dialysis in the nucleus accumbens of conscious rats was used to determine if the increased behavioral response following daily cocaine administration is associated with in increase in extracellular dopamine concentration. Acute injection of cocaine (15 mg/kg, ip) produced and elevation in extracellular dopamine concentration in the nucleus accumbens. Following daily pretreatment with cocaine (15 mg/kg, ip × 4 days), a subsequent acute injection of cocaine (15 mg/kg, ip) significantly elevated the extracellular dopamine levels compared to that produced by a single acute injection. Although the levels extracellular dopamine metabolites was significantly lowered by both acute cocaine and daily cocaine, no difference between these two groups of animals was measured. The increase in extrecellular dopamine following a single acute injection of cocaine was not correlated to the motor stimulant response. However, after daily pretreatment with cocaine the motor stimulant response to acute cacaine was positively correlated with the increased extracellular concentration of dopamine in the nucleus accumbens. These data demonstrate that enhanced dopamine release into the nucleus accumbens may mediate the behavioral sensitization produced by daily injections of cocaine, but that other neural systems are influential in mediating the acute motor stimulant effect of cocaine.
Protein kinase A-dependent recruitment of RNA polymerase II, C/EBPβ and NF-Y to the rat GTP cyclohydrolase I proximal promoter occurs without alterations in histone acetylation

Cyclic-AMP stimulation of GTP cyclohydrolase I (GCH1) gene transcription was investigated in PC12 cells, the protein kinase A-deficient PC12 cell line 126-1B2 and C6 cells using transient transfection assays of proximal promoter reporter constructs and wild type or dominant negative proteins, chromatin immunoprecipitation and real-time quantitative PCR. These studies show that protein kinase A is necessary and sufficient for cAMP-dependent transcription conferred by both the cAMP regulatory element and the adjacent CCAAT-box. In intact cells these cis-elements were shown to bind cAMP response element binding protein, CCAAT-enhancer binding protein beta and nuclear factor-Y, with each protein controlling a different aspect of the cAMP response. Cyclic-AMP acting through protein kinase A stimulated promoter recruitment of CCAAT-enhancer binding protein beta, nuclear factor-Y and RNA polymerase II while depleting the promoter of cyclic-AMP response element binding protein. Stimulation of transcription by cAMP was not associated with increased acetylation of histones H3 and H4 at proximal promoter nucleosomes, indicating that histone acetyltransferases are not involved in this response. Nonetheless, pharmacological inhibition of histone deacetylase activity did increase histone H4 acetylation and the recruitment of RNA polymerase II, indicating that histone acetyltransferases are normally associated with the proximal promoter. Only in C6 cells, however, did inhibition of histone deacetylases stimulate transcription and synergize with cAMP. These experiments provide the first glimpse of the GCH1 gene promoter functioning within intact cells and supply evidence for the involvement of histone acetyltransferase-containing complexes in GCH1 gene transcription.
Shape fluctuations of interacting fluid droplets.

We study the thermally induced shape fluctuations of monodisperse emulsion droplets. The very small amplitude of these fluctuations is clearly resolved by diffusing wave spectroscopy and a theory is derived to describe the measured data. We measure the dependence of the fluctuations on droplet volume fraction $\ensuremath{\varphi}$, thereby directly probing the interplay between droplet interactions and droplet flexibility. The characteristic relaxation frequency of the fluctuations is found to decrease with increasing $\ensuremath{\varphi}$, while their amplitude increases.
Graphical-numerical determination of variable diffusion coefficient in solids

Considerable gain in information in characteristics of diffusion coefficient may be obtained if data are analysed for variable diffusion coefficient instead of for a constant value of diffusivity. This paper presents a simple method for graphical analysis of concentration gradients in solids to determine the diffusion coefficient as a function of concentration. Consideration is given to problems encountered in extrapolation of data. It is shown that, if relative values of diffusion coefficient is the objects of consideration, no great need exists for exacting extrapolation. Two extrapolations are employed on any given functional model; the results of one extrapolation are greater, while those of the other arc less than the results predicted by the model.