cssi/SciSciGPT-SciSciNet huggingface dataset:
Blast Resistance and Energy Absorption of Foam-Core Cylindrical Sandwich Shells under External Blast

Abstract The early time, through-thickness stress wave response of a foam-core, composite sandwich cylindrical shell under external blast is examined in this paper. Solutions for the transient response of the facesheets were derived as stress waves propagated through an elastic–plastic, crushable foam core. These solutions were found to be in good agreement with results from finite element analysis. The blast response of the composite sandwich cylindrical shell was shown to be affected by the magnitude and duration of the pressure pulse. High amplitude, low duration (impulsive) pressure pulses induced the greatest energy absorption. Low amplitude, long duration pressure pulses caused minimal energy absorption. The amount of energy absorbed increased and the failure load decreased with increasing core thickness. Sandwich shells with foams of varying density, compressive modulus and crushing resistance were also examined. The sandwich shells with the foam of the highest density, compressive modulus and crushing resistance (Divinycell HCP100) were found to be the most blast resistant to failure even though no energy was absorbed by them. Per unit weight, however, the shells with a lighter, less stiff and strong, Divinycell H200 foam core were more blast resistant to failure than shells with a Divinycell HCP100 foam core.
Conversion of restrictive mouse cells to permissiveness during sequential and mixed double infection by murine leukemia viruses.

Abstract Conversion from restrictive (two-hit) to permissive (one-hit) kinetics was observed when N- or B-tropic murine leukemia viruses were titrated on mouse embryo fibroblasts of nonpermissive Fv-1 genotype that had previously been nonproductively infected with the same virus at an average multiplicity of one. The effect was transient, disappearing within about 24 hr after the first infection, and was abrogated by exposure of the first virus preparation to increasing doses of ultraviolet light, with a D 37 inactivation dose of 2550 ergs/mm 2 , about three times that for inactivation of viral replication. Prior infection of nonpermissive mouse cells with the NZB xenotropic virus did not alter their restrictive response to later infection with ecotropic viruses. Low multiplicity infection of NIH 3T3 cells with a B-tropic virus, followed by treatment with iodoeoxyuridine, failed to induce productive infection by endogenous or exogenous virus. Cells of F 1 hybrid Fv-1 genotype, which are restrictive for both N- and B-tropic viruses, were converted to permissiveness for virus of either tropism after low multiplicity infection with virus of the opposite tropism. No evidence of NB-tropic recombinant progeny could be detected under these experimental conditions. The implications of these experimental observations with respect to the mechanism of restriction governed by the Fv-1 gene are discussed.
Molecular motions in sucrose-PVP and sucrose-sorbitol dispersions: I. Implications of global and local mobility on stability

To characterize molecular mobility by dielectric spectroscopy and determine the effect of additives on α- and β-relaxation times in amorphous sucrose solid dispersions. Sucrose was co-lyophilized with either PVP or sorbitol. The lyophiles were subjected to dielectric spectroscopy and differential scanning calorimetry. The additives did not have an appreciable effect on the calorimetric Tg. However, dielectric spectroscopy revealed pronounced effects on global mobility (α-relaxation), which correlated with the crystallization tendency of sucrose. The systems were characterized by two β-relaxations, and the relaxation times as well as their temperature dependence were influenced by the additive. Although sorbitol acted as a plasticizer of sucrose with respect to global mobility, it anti-plasticized sucrose in terms of local motions. PVP, on the other hand, acted as an anti-plasticizer with respect to both global and local mobility. The slower β-relaxation in amorphous sucrose was found to correlate with the α-relaxation and was identified as the Johari-Goldstein relaxation. Amorphous systems with identical calorimetric Tg could have significantly different mobility and physical stability as revealed by dielectric spectroscopy. Additive effect on global mobility cannot be a predictor of the effects on local mobility. Additives could also be used to inhibit local mobility.
Electrocatalytic oxidation of oxalic acid at electrodes coated with polymeric metallophthalocyanines

Abstract The overpotential normally associated with the electrochemical oxidation of oxalic acid in aqueous solution is greatly reduced at glassy carbon surfaces modified with polymeric metallophthalocyanine films. The cobalt derivative is particularly active, displaying a peak potential ~ 750 mV less positive than that obtained at a bare electrode. The electrocatalytic process appears to involve initial CoII → CoIII oxidation, and the mechanistic details have been examined using cyclic voltammetry and rotating disk electrochemical methods. The overall reaction is quite rapid, and Levich plots obtained at coated electrodes show only slight deviations from linearity, even at high rotation rates. The observed catalytic current depends linearly on oxalic acid concentration and varies only slightly with film thickness, suggesting that internal charge transport is not rate-limiting under these conditions. The data indicate that the electrocatalytic oxidation of oxalic acid at polymeric cobalt phthalocyanine-coated electrodes belongs to the SR kinetic regime.
Biological rationale for early treatment of dentofacial deformities

Although clinical modification of the growth of the bones comprising the maxillomandibular complex is of major interest to orthodontists, this treatment approach has remained controversial since its inception. Three related issues underlie the debate about orthodontic treatment designed to modify growth of the facial skeleton. Each, if true in most circumstances, would call into question the rationale of treatment designed to correct the orthopedic discrepancy via growth modification (ie, phase 1 treatment), whether or not it is followed by orthodontic correction of the occlusion (ie, phase 2 treatment). First, there is an ingrained assumption that growth of skeletal tissues generally cannot be altered in any clinically meaningful way, at least not by conventional fixed or functional orthodontic appliances. Second, clinical orthodontic experience and more formal studies, often using very different treatment approaches, times of onset and duration, and patient samples, have produced disparate outcomes. Third, there are significant concerns about the validity of the diagnostic criteria used to identify many true growth-related jaw discrepancies at an “early” age, especially in children who are believed to be otherwise normal. This summary is a brief review of the biological foundation for consideration of early orthodontic treatment, with particular emphasis on growth mod
Donor/recipient interactions affecting plasmid transfer among Streptomyces species: A conjugative plasmid will mobilize nontransferable plasmids in soil

Streptomyces parvulus was used as the recipient for plasmid pIJ303 and pIJ211, two conjugative plasmids derived from the self-transmissible plasmid pIJ101. One of the resulting transconjugantS. parvulus strains containing plasmid pIJ303 was used withS. lividans to evaluate the effects of the host strain on the frequency of pIJ303 transfer betweenStreptomyces species. Only 30% ofS. parvulus cells acquired plasmid pIJ303 in crosses in whichS. lividans was the donor, whereas 100% ofS. lividans cells acquired the plasmid whenS. parvulus was the donor. This indicates that the frequency of transfer of the conjugative plasmid was determined by the recipient. The other resulting transconjugantS. parvulus strain containing plasmid pIJ211 was evaluated for its ability to mobilize the nonconjugative plasmid pIJ702 fromS. lividans, on agar and in sterile soil. AfterS. lividans containing pIJ702 was crossed on agar and in sterile soil withS. parvulus containing pIJ211, recombinantS. parvulus colonies carrying pIJ702 and expressing pigments characteristic of both species were recovered, from both agar and soil. Although a large percentage ofS. parvulus transconjugants lost pIJ211 during incubation in soil, the mobilization of pIJ702 fromS. lividans intoS. parvulus still occurred. Plasmid integration into the chromosome of the donor and the transconjugant was evaluated by Southern blot hybridization. Hybridization of plasmid pIJ303, with chromosomal DNA fromS. lividans andS. parvulus transconjugants, using biotinylated DNA, indicated that no integration had occurred. Genetic exchange betweenStreptomyces species also occurred in a liquid medium. The finding of plasmid mobilization in soil is significant. It demonstrates that genetic exchange in the environment can occur between released genetically engineeredStreptomyces species and nativeStreptomyces species that contain conjugative plasmids.
Ultrastructural changes in the cytoplasm of developing amphibian oocytes

The cytoplasm of the amphibian oocyte both prior to and following initiation of vitellogenesis was studied with the electron microscope. The yolk-free oocyte contains in its cytoplasm numerous mitochondria, structurally similar to those of somatic cells. These are frequently arranged in the form of aggregates. Large vesicles are in proximity to these aggregates. These oval or round bodies are enveloped by a limiting membrane which encloses optically transparent material. The Golgi complex was found in the form of clusters of small vesicles together with an array of cisternae. At the stage when the oocyte is elaborating nutritive material in the form of yolk and lipochondria there is an increase in the number of mitochondria and vesicles and the Golgi complex consists essentially of a diminished number of cisternae. The ultrastructure of the yolk platelets, lipochondria, and pigment granules are discussed.
Immobilization hypercalcemia in incomplete paraplegia: Successful treatment with pamidronate

Immobilization hypercalcemia (IH) occurs in adolescent patients with high-level complete tetraplegia, but it has not been reported in patients with incomplete paraplegia. We describe two adolescent patients with low-level incomplete paraplegia who developed IH during comprehensive rehabilitation. Conventional therapies with hydration, diuresis, and calcitonin were not effective. Finally, a single-dose infusion of pamidronate, an amino-bisphosphonate, completely resolved the hypercalcemia. Although it has a pharmacologic profile similar to etidronate, pamidronate is more potent, being effective in a single dose, has fewer adverse effects, and has a longer action than etidronate. These features make pamidronate more suitable for the treatment of severe IH in rehabilitation settings. It is reasonable to consider immobilization as the cause of hypercalcemia in low-level incomplete paraplegic patients who have other contributing factors.
Finite Element Analysis of the Effect of Overlapping Impacts of Laser Shock Peening Within Annealed AISI 1053 Steel

Laser shock peening is a surface treatment technique similar to conventional shot peening. The laser induced plasma causes plastic deformations and compressive residual stresses in materials which are useful for developing improved properties in the fields of fatigue, wear or stress corrosion cracking. Finite element method is an efficient tool to predict the mechanical effects and the deformations caused due to laser shock peening, which otherwise are difficult to calculate due to the severe pressure imparted in a very short period of time. This paper presents the calculations performed using ABAQUS, for the simulation of multiple laser shock processing in order to evaluate the residual stress and the deformation of the material. A study of the effect of multiple laser shocks and their extent of overlap on the affected depths and the tensile and compressive residual stresses has been discussed. FEM calculations of residual stress fields and extent of surface deformation in annealed AISI 1053 steel has been investigated along with a study of the distribution of tensile and compressive residual stresses due to the difference in the extent of overlap of the multiple shocks.Copyright © 2010 by ASME
Test results of the OGT2500 Gas Turbine Engine Running on Alternative Fuels: BioOil, Ethanol, BioDiesel and Crude Oil

This paper describes the results of an on going development program aimed at determining the technical feasibility of utilizing alternative fuels such as bio-mass derived BioOil, Ethanol, Bio-Diesel and bituminous Crude Oil in a 2.5 MW GT2500 industrial Gas Turbine Engine. This gas turbine engine was designed and manufactured by “Zorya-Mashproekt” in the Ukraine and further modified for the alternative fuels application through a join development program between “Zorya-Mashproekt” and Orenda Aerospace Corporation in Canada. The modification of the GT2500 Gas Turbine Engine hot section and combustion system to operate on liquid alternative fuels are described. Also described is an engine hot section online cleaning system and features of the fuel-handling module, which carries out fuel preheating and preprocessing. A test rig equipped with a load bank was designed and built to test the modified GT2500 Gas turbine Engine on different alternative fuels (full speed/full power). Results of the modified GT2500 gas turbine engine operation along with the emissions data are presented. The tests proved the technical feasibility of operating this gas turbine engine on the alternative fuels mentioned above. Based on these results a power generation package with the engine and fuel handling module have been accepted for commercial operation in a pilot plant under construction in West Lorne, Ontario, Canada.© 2005 ASME
Defining the Turing Jump

The primary notion of effective computability is that provided by Turing machines (or equivalently any of the other common models of computation). We denote the partial function computed by the eth Turing machine in some standard list by φe. When these machines are equipped with an “oracle” for a subset A of the natural numbers ω, i.e. an external procedure that answers questions of the form “is n in A”, they define the basic notion of relative computability or Turing reducibility (from Turing (1939)). We say that A is computable from (or recursive in) B if there is a Turing machine which, when equipped with an oracle for B, computes (the characteristic function of) A, i.e. for some e, φe = A. We denote this relation by A ≤T B which we read as A is (Turing) reducible to B or A is recursive (computable) in B. This relation is transitive and reflexive and so induces an equivalence relation ≡T (A ≡T B ⇔ A ≤T B ∧ B ≤T A) and a partial order also denoted by ≤T on the equivalence classes. These equivalence classes are called (Turing) degrees and the equivalence class of a set A ⊆ ω is called its degree. It is typically denoted by a or deg(A). ∗Partially supported by NSF Grant DMS-9802843. †Partially supported by NSF Grant DMS-97-96121.
Polycomb (PcG) Proteins, BMI1 and SUZ12, Regulate Arsenic-induced Cell Transformation

Inorganic arsenic is a well-documented human carcinogen associated with cancers of the skin, lung, liver, and bladder. However, the underlying mechanisms explaining the tumorigenic role of arsenic are not well understood. The present study explored a potential mechanism of cell transformation induced by arsenic exposure. Exposure to a low dose (0.5 μm) of arsenic trioxide (As(2)O(3)) caused transformation of BALB/c 3T3 cells. In addition, in a xenograft mouse model, tumor growth of the arsenic-induced transformed cells was dramatically increased. In arsenic-induced transformed cells, polycomb group (PcG) proteins, including BMI1 and SUZ12, were activated resulting in enhanced histone H3K27 tri-methylation levels. On the other hand, tumor suppressor p16(INK4a) and p19(ARF) mRNA and protein expression were dramatically suppressed. Introduction of small hairpin (sh) RNA-BMI1 or -SUZ12 into BALB/c 3T3 cells resulted in suppression of arsenic-induced transformation. Histone H3K27 tri-methylation returned to normal in BMI1- or SUZ12-knockdown BALB/c 3T3 cells compared with BMI1- or SUZ12-wildtype cells after arsenic exposure. As a consequence, the expression of p16(INK4a) and p19(ARF) was recovered in arsenic-treated BMI1- or SUZ12-knockdown cells. Thus, arsenic-induced cell transformation was blocked by inhibition of PcG function. Taken together, these results strongly suggest that the polycomb proteins, BMI1 and SUZ12 are required for cell transformation induced by organic arsenic exposure.
Interpreting behavioral, biomedical, and psychological relationships in chronic disease from 2 × 2 tables using correlation☆☆☆

Correlations of 0.3 and 0.4 in psychological studies in chronic illness (e.g. diabetes) have been criticized as having little clinical importance. The present article suggests that correlation coefficients be interpreted as binomial effect size displays (BESD) as a means of gleaning the clinical importance of a given correlation coefficient. The BESD is easily understood, computed, and applied to research in chronic disease. An illustration is provided in which a r of 0.2 is shown to correspond to a BESD in which the success rate is improved from 40 to 60%. Using BESD to interpret the meaningfulness of relationships, correlations as low as 0.2 may have clinical importance.
Preparation and Crystal Structure Analysis of Magnetoplumbite-Type BaGa12O19

Abstract Single-crystal X-ray analysis has verified preparation of an ideal magnetoplumbite-type phase in the ternary barium hexagallate system. X-ray refinement was carried out by the full-matrix least-squares onF2method, to giveR1=4.61% and wR2=7.76% for 54 parameters and 374 independent reflections withI>2σ(I). Microanalysis data yields a composition of Ba1.07Ga11.95O19. The crystal chemistries of the barium hexagallate and barium hexaaluminate systems are compared and discussed. Crystal data for BaGa12O19:M=1277.98, space groupP63/mmc(No. 194),a=5.8140(8) A,c=23.038(5) A,V=674.4(2) A3,Z=2,Dc=6.293 g cm−3, MoKα,λ=0.71073 A,μ=26.532 mm−1, 2θmax=56.74°.
Multicultural Psychology in Iceland: Meeting the Needs of a Changing Society

Cultural diversity in Iceland has increased substantially in recent years, but research on multicultural topics within Icelandic psychology is still very limited. Icelandic psychologists' self-repo...
A robust continuation method to pass limit-point instability

In this paper a homotopy map is proposed to pass limit points of snap-through problems encountered in geometrically nonlinear finite element analysis. In the vicinity of such points, the tangent stiffness matrix becomes ill-conditioned, which detrimentally affects the convergence of numerical schemes such as Newton-Raphson method. The proposed method overcomes this problem by tracing a well-conditioned path instead of equilibrium path in the vicinity of critical points. This allows the solution procedure to bypass the critical point without experiencing ill-conditioning. An instance of such a well-conditioned path is constructed for limit points. In particular, starting from the stable (or unstable) configuration, we compute the unstable (or stable) configuration via a robust numerical procedure. Further, since the tangent matrix derivation is consistent with the residual force computation, the quadratic convergence of Newton-Raphson method is retained.
Scrapie prions: a three-dimensional model of an infectious fragment.

Backgound: A conformational change seems to represent the major difference between the scrapie prion protein (PrP Sc ) and its normal cellular isoform (PrP C ). We recently proposed a set of four helix bundle models for the three-dimensional structure of PrP C that are consistent with a variety of spectroscopic and genetic data. Results: We report a plausible model for the three-dimensional structure of a biologically important fragment of PrP Sc . The model of residues 108–218 was constructed by an approach that combines computational techniques and experimental data. The proposed structures of this fragment of PrP Sc display a four-stranded β -sheet covered on one face by two α -helices. Residues implicated in the prion species barrier are found to cluster on the solvent-accessible surface of the β -sheet of one of the models. This interface could provide a structural template that would assist the conversion of PrP C to PrP Sc and hence direct prion propagation. Conclusion: Molecular models of the PrP isoforms should prove very useful in developing structural hypotheses about the process by which PrP C is transformed into PrP Sc , the mechanisms by which PrP gene mutations give rise to the inherited human prion diseases, and the species barrier that seems to protect humans from animal prions. It seems likely that PrP C represents a kinetically trapped intermediate in PrP folding.
Cortical development: receiving reelin.

Abstract Recent genetic and biochemical studies indicate that lipoprotein receptors are components of the neuronal receptor for Reelin, mediating the glycoprotein's essential function in cortical development. At least eight cadherin-related neuronal receptors may also play a part in this signalling system.
Contemporary Survival and Outcomes Following Airway Dehiscence Post Lung Transplantation: A Significant Price to Pay

Results: The oneand 5 year survival rates in Group 1 were significantly better than Group 2 (87% and 69% vs. 80% and 34%, respectively, p< 0.001, log rank test). In multivariate analysis, a ZRS consisting of ≥ 3 comorbidities and ZDS of ≥ 3 points were found to be significant risk factors for mortality in Group 2 (N= 14 HR 2.79; 95%CI 1.29-6.02 and N= 37 HR 2.30; 95%CI 1.31-4.04, respectively). In Group 1, ZRS of ≥ 3 was also found to be a risk factor for mortality using the same multivariate model (N= 21, HR 2.50; 95%CI 1.37-4.58). In Group 1, ZDS ≥ 3 was not found to be a risk factor. Conclusion: The accumulation of three ore more comorbidities was a risk factor for mortality in both young and old lung transplant recipients. The negative impact of extended donor lungs seems stronger in older recipients. In order to maximize posttransplant outcome, careful candidate selection and risk calculation weighing comorbidities is crucial.
Nitrogen beam RBS for concentration uniformity measurements of SiO2:Au thin layer co-depositions

Co-depositions of gold and silica (amorphous silicon dioxide) on silica substrates using the ion beam assisted deposition (IBAD) facility at the Center for Irradiation of Materials at Alabama A&M University (CIM-AAMU) were analyzed for Au concentration, distribution and uniformity within the layer deposited. High resolution RBS using 4 MeV nitrogen ions combined with RUMP simulations accurately provided useful feedback to the fabrication process.
Myosin expression in the developing ascidian embryo.

Myosin accumulation was examined in developing ascidian embryos by measuring its ATPase activity and by resolving myosin heavy chains on polyacrylamide gels. Both procedures used a myosin-enriched fraction that was prepared by exploiting the unusual solubility properties of this protein. Myosin ATPase was first observed at neurulation and increased 25- to 50-fold by the time of larval hatching, a sequence similar to that found previously for muscle acetylcholinesterase. This similarity to acetylcholinesterase,and the finding of at least two-thirds of the ATPase activity in the larval tail,imply that most of the myosin studied was muscle myosin. The pattern of expression based on ATPase assays was confirmed in part by gel analysis, but since this technique was less sensitive the appearance of myosin heavy chain was not demonstrated unambiguously until later in development. As found earlier with acetylcholinesterase, actinomycin D treatment only interfered with accumulation of myosin ATPase during early stages of increasing enzymatic activity. Despite certain similarities noted in their ontogeny, differences in the initial increase in the activity of these enzymes and the time of their first response to actinomycin D suggest that the events concerned with the expression of acetylcholinesterase occur 1 hour before those of myosin ATPase.The appearance of these two proteins, representing different enzymes of the muscle cell, is probably controlled independently.
Yield, Flowering, and Leaf Area Index of Okra-Leaf and Normal-Leaf Cotton Isolines

Cotton (Gossypium hirsutum L.) with alternative leaf morphologies, such as the deft-shaped okra-leaf types, offers production advantages such as earlier maturity. However, okra-leaf types have not been commercially viable in the USA. The objectives of this study were to test okra-leaf types in genetic backgrounds varying in maturity and region of adaptation and to provide growth data that might explain yield differences. Four to seven pairs of selected cotton okra- and normal-leaf isolines (and check cultivars) were grown in the field in one 2-yr (Exp. A) and two 1-yr experiments (Exp. B and C) from 1994 to 1996 near Stoneville, MS, in row spacings of 76 and 102 cm. In Exp. A, average lint yields of okra-leaf isolines were greater overall than normal-leaf lines (847 vs. 749 kg ha -1 ), but in Exp. C, the opposite was true (1020 kg ha -1 for okra- vs. 1130 kg ha -1 for normal-leaf types). No yield difference was found between leaf types in Exp. B. Yields of okra-leaf lines were either equal to or less than those of recently released high-yielding commercial types whose okra-leaf isolines are not yet available. Okra-leaf types were usually 1 to 4 d earlier in maturity than their normal-leaf counterparts, possibly contributing to their overall yield advantage in Exp. A. When only okra-leaf isolines were considered, Tamcot HQ95 ranked first or second highest for yield and was the earliest to mature in all three tests. In general, the row-spacing effect and interactions with row spacing were not significant. The results indicate that the okra-leaf trait should be considered for producing future cultivars.
Latin American Immigration to the United States.

This essay provides an overview of immigration from Latin America since 1960, focusing on changes in both the size and composition of the dominant streams and their cumulative impact on the U.S. foreign-born population. We briefly describe the deep historical roots of current migration streams and the policy backdrop against which migration from the region surged. Distinguishing among the three major pathways to U.S. residence – family sponsorship, asylum, and unauthorized entry – we explain how contemporary flows are related both to economic crises, political conflicts, and humanitarian incidents in sending countries, but especially to idiosyncratic application of existing laws over time. The concluding section highlights the importance of investing in the children of immigrants to meet the future labor needs of an aging nation.
PLASMA OSCILLATIONS WITH DIFFUSION IN VELOCITY SPACE

A model of plasma oscillations in the presence of small-angle collisions is presented which admits of exact analytic solution. Certain features of the true collision terms are preserved. Namely, the effect of collisions is represented by a diffusion in velocity space, which makes the distribution function tend to the Maxwell distribution, and which conserves the number of particles. In the limit of infrequent collisions the results of Landau are recovered.
Palmitic and stearic fatty acids induce caspase-dependent and -independent cell death in nerve growth factor differentiated PC12 cells

Apoptotic cell death has been proposed to play a role in the neuronal loss observed following traumatic injury in the CNS and PNS. The present study uses an in vitro tissue culture model to investigate whether free fatty acids (FFAs), at concentrations comparable to those found following traumatic brain injury, trigger cell death. Nerve growth factor (NGF)-differentiated PC12 cells exposed to oleic and arachidonic acids (2 : 1 ratio FFA/BSA) showed normal cell survival. However, when cells were exposed to stearic and palmitic acids, there was a dramatic loss of cell viability after 24 h of treatment. The cell death induced by stearic acid and palmitic acid was apoptotic as assessed by morphological analysis, and activation of caspase-8 and caspase-3-like activities. Western blotting showed that differentiated PC12 cells exposed to stearic and palmitic acids exhibited the signature apoptotic cleavage fragment of poly (ADP-ribose) polymerase (PARP). Interestingly, blockade of caspase activities with the pan-caspase inhibitor z-VAD-fmk failed to prevent the cell death observed induced by palmitic or stearic acid. RT-PCR and RNA blot experiments showed an up-regulation of the Fas receptor and ligand mRNA. These findings are consistent with our hypothesis that FFAs may play a role in the cell death associated with trauma in the CNS and PNS.
Induction of chromosome aberrations in cultured human cells by ethylenimine and its relation to cell cycle

Abstract Human cells (WI-38, passage 22 and leukocyte cultures) were treated in vitro with ethylenimine solution of various concentrations for various lengths of time before fixation. The findings are as follows: 1. (1) Ethylenimine was cytotoxic to the cells at the concentration of IO −2M or higher. 2. (2) Only chromatid gaps, breaks, and exchanges were recovered. 3. (3) Cells treated for 3.5 h before fixation with ethylenimine showed little damage; only 7% of the cells showed aberrations. This is not significantly higher than the control value of 4%. On the other hand, 29% of the cells had aberrations when treated similarly for 8 h. This suggests that aberrations are induced primarily in the S-period. 4. (4) This was confirmed by autoradiography by treating leukocyte cultures for 8 h with ethylenimine and [3H]thymidine. 56 cells out of 100 had aberrations. Of these 56 cells all but 4 were labeled. 5. (5) A significantly high number of aberrations were still found 7 days after the treatment. This might be similar to the delayed action found in Drosophila, although one cannot rule out the possibility that the chemical or its active product persisted in the cytoplasm after the actual treatment. The question of the sensitivity of G1 cells to ethylenimine remains unresolved.
Apparently First Closed-Form Solution for Vibration of Functionally Graded Rotating Beams

Apparently the first closed-form solution for vibrations of inhomogeneous rotating beams made of functionally graded material is presented. A special version of the semi-inverse method, developed by the first author, is employed. Both the mode shape and the flexural rigidity are expressed as suitable polynomial functions. Generalization of the presented methodology to trigonometric functions is now underway and will be reported elsewhere.
Pelvic computed tomography of breast carcinoma patients. Should it routinely be added to abdominal computed tomography

BACKGROUND This study was conducted to determine if pelvic computed tomography (CT) should routinely be appended to abdominal CT in the workup of patients with breast carcinoma. METHODS The abdominal-pelvic CTs of 139 breast carcinoma patients (195 exams) were reviewed. Scans were grouped by indication and whether pelvic pathology was known before CT. Pelvic CT results were correlated with their effect on patient management. RESULTS Among the 119 patients without pre-CT evidence of pelvic disease, a nonosseous pelvic metastasis was identified in only 1; this patient also had liver metastases and management was not changed. No unsuspected pelvic CT finding altered therapy for breast carcinoma. However, three patients underwent surgery for asymptomatic masses discovered on pelvic CT; all were benign. CONCLUSIONS Pelvic CT is unlikely to affect the management of patients with breast carcinoma by detecting occult metastatic disease. Cancer 1997; 79:500-4. © 1997 American Cancer Society.
Preparation and Characterization of Group 12 Thiolate Complexes and Evaluation of Their Potential as Precursors for II-VI Semiconductors

We have prepared compounds having the general formula M(SR)2 (M = Zn, Cd; R = i-Pr, t-Bu, Bz) and Hg(SR)CI (R = i-Pr, Bz) and investigated their use as potential sources in the preparation of metal sulfides from molecular precursors. Selected examples of the prepared compounds have been studied by single crystal x-ray diffraction. Decomposition has been carried out both in the solid state and by heating a suspension of a metal thiolate in a high boiling hydrocarbon. The decomposition products have been studied by GC/MS (liquids) and XRD (solids).
Unraveling Cyclic Deformation Mechanisms of a Rolled Magnesium Alloy Using In-situ Neutron Diffraction

Abstract In the current study, the deformation mechanisms of a rolled magnesium alloy were investigated under cyclic loading using real-time in situ neutron diffraction under a continuous-loading condition. The relationship between the macroscopic cyclic deformation behavior and the microscopic response at the grain level was established. The neutron diffraction results indicate that more and more grains are involved in the twinning and detwinning deformation process with the increase of fatigue cycles. The residual twins appear in the early fatigue life, which is responsible for the cyclic hardening behavior. The asymmetric shape of the hysteresis loop is attributed to the early exhaustion of the detwinning process during compression, which leads to the activation of dislocation slips and rapid strain-hardening. The critical resolved shear stress for the activation of tensile twinning closely depends on the residual strain developed during cyclic loading. In the cycle before the sample fractured, the dislocation slips became active in tension, although the sample was not fully twinned. The increased dislocation density leads to the rise of the stress concentration at weak spots, which is believed to be the main reason for the fatigue failure. The deformation history greatly influences the deformation mechanisms of hexagonal-close-packed-structured magnesium alloy during cyclic loading.
Evaluation of a behavioral method for objective vision testing and identification of achromatopsia in dogs.

Objective—To develop a quantifiable behavioral test for identification of achromatopsic dogs based on visual performance. Animals—14 dogs. Procedures—A 3.6-m-long obstacle-avoidance course with 6 obstacle panels was developed from a preliminary 2.4-m-long course. Achromatopsic and visually normal control dogs were run through the course at 4 ambient light intensities (from dim to bright: 0.2, 25, 65, and 646 lux). Completion of 4 runs ranging from dimmest to brightest light intensity constituted 1 complete trial. Each dog underwent 3 trials. Transit times were measured and compared between dog groups and between light intensities by use of a generalized linear model and ANOVA. Results—At the 3 highest light intensities, the achromatopsic dogs needed significantly more time to pass through the obstacle course than the control animals. Compared with the mean transit time at the lowest light intensity, mean transit times were 2.6 times as long at 25 lux, 3.2 times as long at 65 lux, and 5.7 times as long at ...
Association of Increased Levels of Fibrinogen and the –455G/A Fibrinogen Gene Polymorphism with Chronic Periodontitis

Background: Fibrinogen is one of the acute-phase proteins whose levels are elevated during periodontal disease. Recent studies suggest that excessive fibrinogen production might play a role in upregulating host immune responses. In addition, there is a relationship between the –455G/A polymorphism (HaeIII) in the 5' flanking region of the β-fibrinogen gene promoter and increased fibrinogen levels. In this study, we investigated the distribution of the –455G/A polymorphism and the relationship of this specific genotype to fibrinogen levels in periodontitis patients. Methods: In order to assess the –455G/A polymorphism, restriction fragment length polymorphism (RFLP) analysis with HaeIII enzyme was performed in the promoter region of the β-fibrinogen gene. This was carried out on 79 chronic periodontitis patients as compared to 75 periodontally healthy subjects, matched to age, gender, and race. Fibrinogen levels were determined by the radial immunodiffusion assay (RID). Results: The frequency of homozygoci...
Ultrashort pulse propagation in near-field periodic diffractive structures by use of rigorous coupled-wave analysis

We present a method for near-field analysis of ultrashort optical pulse propagation in periodic structures—including subwavelength and resonant grating structures—based on the integration of Fourier spectrum decomposition and rigorous coupled-wave analysis (RCWA). We discuss the spectral decomposition, including considerations for computational efficiency, the application of the RCWA method to compute the internal and external fields of the structure, and the synthesis of the resulting fields to obtain the time-domain solution. We apply this tool to the analysis of two photonic structures: (1) a nanostructured polarization-selective mirror that exhibits the desired broadband performance characteristics when operated at the design wavelength but yields strongly diminished polarization selectivity and modulation of the pulse envelope at an offset wavelength and (2) a two-mode coupled waveguide structure that produces from one incident pulse two transmitted pulses whose temporal separation depends on the waveguide geometry. In both examples, we apply our new modeling tool to investigate the near fields and find that near-field effects are critical in determining the performance characteristics of nanostructured devices. Furthermore, detailed observation and understanding of near-field phenomena in nanostructures may be applied to the design of novel photonic devices.
English Speech Sound Development in Preschool-Aged Children From Bilingual English–Spanish Environments

Purpose English speech acquisition by typically developing 3- to 4-year-old children with monolingual English was compared to English speech acquisition by typically developing 3- to 4-year-old children with bilingual English–Spanish backgrounds. We predicted that exposure to Spanish would not affect the English phonetic inventory but would increase error frequency and type in bilingual children. Method Single-word speech samples were collected from 33 children. Phonetically transcribed samples for the 3 groups (monolingual English children, English–Spanish bilingual children who were predominantly exposed to English, and English–Spanish bilingual children with relatively equal exposure to English and Spanish) were compared at 2 time points and for change over time for phonetic inventory, phoneme accuracy, and error pattern frequencies. Results Children demonstrated similar phonetic inventories. Some bilingual children produced Spanish phonemes in their English and produced few consonant cluster sequences...
Epidemiologic and Genetic Studies of Congenital Heart Disease in the Dog

The prevalence rate for cardiovascular malformations in dogs presented to a large university veterinary clinic was 6.8 per 1000. Patent ductus arteriosus, as in man, was found predominantly in females. Breed-specific prevalence rates were significantly greater in purebred dogs than in mongrels, and the breed distributions of patent ductus arteriosus, pulmonic stenosis, subaortic stenosis, persistent right aortic arch, and tetralogy of Fallot were significantly different than would be expected if all breeds were equally susceptible to each type of malformation. On the basis of these observations, two hypotheses were made: (1) Genetic factors are determinants of certain types of congenital heart disease in the dog. (2) These genetic factors have specific effects on cardiac morphogenesis, resulting in specific types of cardiovascular malformations. Preliminary genetic studies confirmed the specific hereditary transmission of valvular pulmonic stenosis in beagles, persistent right aortic arch in German shepherds, and conal septal defects (including ventricular septal defects and tetralogy of Fallot) in keeshonden. The pattern of inheritance of these defects was not consistent with any simple genetic hypothesis. Patent ductus arteriosus in dogs of poodle ancestry and fibrous subaortic stenosis in Newfoundlands were shown provisionally to be transmitted in a manner consistent with autosomal dominant inheritance. The significance of these findings is considered in relation to present and future understanding of the etiology and pathogenesis of congenital heart disease.
Thrombolysis in elderly patients with acute myocardial infarction.

The efficacy of thrombolytic therapy in the elderly remains a topic of ongoing debate. Although elderly patients account for a disproportionate amount of cardiovascular mortality, they have typically been underrepresented in randomized clinical trials. A meta-analysis of these trials suggests a survival benefit, albeit small, of thrombolytic therapy in the elderly. Thrombolytic therapy, in combination with either glycoprotein IIb/IIIa inhibitors or low-molecular weight heparin, poses an increased hazard in the elderly. Observational studies of thrombolytic therapy in the elderly portray a far worse outcome than the randomized clinical trials and raise the possibility of increased mortality. To date, no randomized trial has compared thrombolytic and primary coronary intervention in the elderly. However, multiple observational studies indicate a low risk of intracerebral hemorrhage and improved survival when a strategy of primary coronary intervention is employed. Future trials and observational studies should elucidate the ideal reperfusion strategy in the elderly.
Analysis of the human liver/bone/kidney alkaline phosphatase promoter in vivo and in vitro

Abstract We have carried out an analysis of the promoter for the human liver/bone/kidney alkaline phosphatase (LBK AP) gene. Using transient transfection assays, the intact promoter directs equal expression of a linked cat gene in Saos-2 cells (osteoblast-derived cells which express very high levels of endogenous LBK AP mRNA) and in HeLa and HepG2 cells (which express low levels of endogenous message). The activity of the transfected promoter apparently mimics the true in vivo situation since nuclear run-on assays employing Saos-2 and HeLa cells indicate that the endogenous gene is transcribed at approximately the same rate in these two cell types. Transfections of a series of 5' deletion mutants indicate that promoter activity is dependent on multiple motifs, which possibly include several putative Sp1 binding sites and a TATA box. The LBK AP promoter also directs accurate transcription initiation in HeLa whole cell extracts and in vitro activities of the 5' deletion mutants also suggest that the promoter utilizes multiple motifs.
The Federal Reserve Act and Federal Reserve Policies

I. Introduction, 371. — II. Origins of the Act, 373. — III. Nature of the System, 376. — Eligibility, 378. — Interpretation of eligibility provisions by the Board, 379. — Goodness versus eligibility, 381. — The problem of controlling the use of reserve bank credit, 383. — IV. The position of control, 386. — Open market operations, 387. — Control and the magnitude of member bank indebtedness, 393. — Rediscount rates, 394: — Rate structure in Great Britain and the United States and the significance of the buying rate, 396. — An ineffective discount policy, 399. — Direct methods, 399. — V. Conclusion, 406.
Note on the Bremsstrahlung Produced by Protons

The bremsstrahlung produced by protons is discussed on the assumption that the anomalous magnetic moment can be described in terms of a Pauli type interaction with the electromagnetic field. The result of a perturbation theoretical calculation of the cross section is given, and a comparison is made to the approximate method of Weizs\"acker and Williams. Reasons are given for the failure of the Weizs\"acker method in special cases.
Production and characterization of thick, thin and ultra-thin chitosan/PEO films

Abstract The current study focused on the functionality of chitosan/PEO films as affected by preparation methods, film composition, and thickness. Mixtures of chitosan and PEO with different blend ratios (100/0–50/50) were dissolved in 1% acetic acid to form 1% blend solutions. Films prepared by casting of 20 g or 10 g film-forming solution per 50-mm diameter polystyrene Petri dish or by using spin-coating method had an average thickness of 87.41 ± 5.44 μm (thick), 37.88 ± 2.41 μm (thin), and 70.47 ± 3.06 nm (ultra-thin), respectively. Development of polymer crystallization was monitored by X-ray diffractometer at ambient temperature; the metal-binding capacity of the films was assessed based on removal of chromium ions from K 2 CrO 4 solution, and the antibacterial properties were tested against Escherichia coli K-12. The crystallization extent of the chitosan/PEO films decreased with decreased thickness as a consequence of faster solvent evaporation during film formation. Decreasing the thickness of the films increased the surface-to-mass ratio, what resulted in higher number of available active sites on the film surface per unit weight of chitosan, and promoted the metal-binding efficiency of the films. Ultra-thin chitosan/PEO films showed a significantly higher chromium-binding capacity [26.47–70.86 mg Cr(VI)/g film] compared to the cast films [0.73–7.59 mg Cr(VI)/g film]. However, these nano-thin films did not show significant antibacterial efficiency, most likely due to their extremely low weight and consequently insufficient chitosan concentration in the inoculated test tubes to kill significant number of bacteria.
Homosexuality, Ethics and Identity Synthesis

Implicit metaphysical assumptions concerning the nature of sexual orientation are reflected in the language used to frame ethical debates concerning "reorientation" therapies. An alternative metaphysical construal is presented concerning sexual orientation and sexual identity development and synthesis. This alternative construal allows for humility concerning what we know and do not know about sexual orientation, underscores the client's self-determination and autonomy, and demonstrates regard for personal and religious valuative frameworks. Rather than focusing on therapies aimed specifically at sexual reorientation, clinicians would do well to provide clients with informed consent and to facilitate identity development and synthesis in keeping with their clients' requests for professional services.
Prescription, over-the-counter, and herbal medicine use in a rural, obstetric population.

Abstract Objective: The purpose of this study was to identify the medications that are consumed by a rural obstetric population during pregnancy. Study Design: Over a period of 26 months, pregnant women were interviewed about medication use. Interviews on subsequent visits provided a longitudinal study of medication usage and discontinuation. Trend differences were analyzed according to the number of medications, the trimester of use, and insurance status. Results: Five hundred seventy-eight participants had 2086 interviews. The compilation of the interviews showed that 95.8% of the participants took prescription medications, 92.6% of the participants self-medicated with over-the-counter medications, and 45.2% of the participants used herbal medications. Over time, consumption of over-the-counter medications exceeded prescription medication use. Fifteen percent of the pregnant women took ibuprofen at some point during the pregnancy (5.7% in the third trimester). Eight percent of the women were noncompliant and 20% incompletely compliant with prenatal vitamin and mineral formulations. Conclusion: Medication use was substantial in this population. Medications (eg, ibuprofen) that are contraindicated in pregnancy were used at unexpectedly high rates. Of the three medication classes, over-the-counter medications were used most frequently. (Am J Obstet Gynecol 2003;188:1039-45.)