cssi/SciSciGPT-SciSciNet huggingface dataset:
β-Adrenergic blockers prevent short photoperiod-induced gonadal regression, but not melatonin-induced regression in male syrian hamsters

Pineal melatonin synthesis is regulated by norepinephrine at beta-adrenergic receptors on pinealocytes. Melatonin released from the pineal is believed to be responsible for short photoperiod-induced gonadal regression. By blocking melatonin production at the beta-adrenergic receptor with beta-adrenergic antagonists, short photoperiod-induced gonadal regression was prevented. Propranolol or nadolol injected daily in the late afternoon prohibited short photoperiod-produced testicular regression in male Syrian hamsters. Likewise, propranolol and nadolol pellets were able to block short photoperiod-induced gonadal regression. Interestingly, in the presence of beta-adrenergic antagonists, gonadal regression was still produced by daily afternoon injections of melatonin. These results indicate that propranolol or nadolol can be used to "pharmacologically pinealectomize" hamsters and block the physiological action of the pineal.
Endogenous antigen presentation by MHC class II molecules.

T cell recognition of antigen requires that a complex form between peptides derived from the protein antigen and cell surface glycoproteins encoded by genes within the major histocompatibility complex (MHC). MHC class II molecules present both extracellular (exogenous) and internally synthesized (endogenous) antigens to the CD4 T cell subset of lymphocytes. The mechanisms of endogenous antigen presentation are the subject of this review. Isolation and amino acid sequencing of peptides bound to the class II molecule indicate that a very high proportion (70–90%) of the total peptides presented by the class II molecule are in fact derived from the pool of proteins that are synthetized within the antigen-presenting cell (APC). This type of sequence information as well as the study of model antigens has indicated that proteins expressed in a diversity of intracellular sites, including the cell surface, endoplasmic reticulum and cytosol can gain access to the class II molecule, albeit with different efficiencies. The main questions that remain to be answered are the intracellular trafficking patterns that allow colocalization of internally synthesized antigens with the class II molecule, the site(s) within the cell where peptide: class II molecule complex formation can take place and whether presentation of ‘foreign’ as well as ‘self’ antigens takes place by mechanisms that vary from one cell type to another or that vary with the metabolic state of the APC. If such variability exists, is would imply that the array of peptides displayed by class II molecules at the cell surface has similar variability, a possibility that would impact on self tolerance and autoimmunity.
Comparison of the quality of protection elicited by toxoid and peptide liposomal vaccine formulations against ricin as assessed by markers of inflammation

Ricin is a very toxic substance which inhibits protein synthesis and produces severe tissue damage and inflammation. It is very potent when inhaled as an aerosol and protection has been examined in a series of studies using vaccine candidates including a formaldehyde inactivated ricin toxoid and the A chain of ricin, a polypeptide equivalent to half of the toxin molecule. Initially, subcutaneous injections of both compounds were found to protect against inhaled ricin but not without some subsequent adverse signs. Intra-pulmonary vaccination using liposomal formulations of these compounds was investigated with a view to improving lung condition following challenge. Using the humoral and local pulmonary immune responses as indices of vaccine performance, no significant difference between toxoid or peptide vaccines was found. In the third and current study, the quality of lung protection by vaccines was assessed using markers of inflammation. Thus, the profiles of inflammatory cell and protein influx into the lung were determined following intratracheal (i.t.) challenge with ricin of rats treated with liposomal vaccine formulations. Results showed that liposomal ricin toxoid offered a better quality of protection with a significantly lower influx of polymorphonuclear leucocytes (neutrophils) and little pulmonary oedema compared with the A chain/liposome formulation. Further, there was no significant difference between the quality of protection offered by the A chain when administered subcutaneously or locally into the lung by i.t. instillation. Liposomal ricin toxoid is a good candidate vaccine and optimised pulmonary delivery by inhalation should be further examined.
A Perturbation Approach for Predicting Wave Propagation in One-Dimensional Nonlinear Periodic Structures

Wave propagation in one-dimensional nonlinear periodic structures is investigated through a novel perturbation analysis and accompanying numerical simulations. Several chain unit cells are considered featuring a sequence of masses connected by linear and cubic springs. Approximate closed-form, first-order dispersion relations capture the effect of nonlinearities on harmonic wave propagation. These relationships document amplitude-dependent behavior to include tunable dispersion curves and cutoff frequencies, which shift with wave amplitude. Numerical simulations verify the dispersion relations obtained from the perturbation analysis. The simulation of an infinite domain is accomplished by employing viscous-based perfectly matched layers appended to the chain ends. Numerically estimated wavenumbers show good agreement with the perturbation predictions. Several example chain unit cells demonstrate the manner in which nonlinearities in periodic systems may be exploited to achieve amplitude-dependent dispersion properties for the design of tunable acoustic devices.
K -shell x-ray production cross sections for 1.0-4.4-MeV α particles on selected thin targets of Z = 22 − 34

K-shell x-ray production cross sections for 1.0--4.4 MeV $alpha$ particles have been measured. The elements selected were Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ge, and Se, and all data were for thin targets evaporated onto thin carbon backings. The measured cross sections are compared with predictions of the plane-wave Born approximation (PWBA), the PWBA with binding-energy and trajectory corrections, and the binary-encounter approximation. It is found that the PWBA with both corrections fits the data best for all elements and energies considered. (AIP)
Phenotypic and functional analysis of bone marrow progenitor cell compartment in bone marrow failure

Many laboratory findings have demonstrated that the haemopoietic stem cell compartment is defective in aplastic anaemia (AA). AA bone marrow (BM) and peripheral blood (PB) are profoundly deficient in colony-forming cells, and AA progenitors fail to proliferate in long-term assays even in the presence of an intact stroma. Our study was designed to characterize some quantitative and qualitative aspects of the progenitor cell defect in AA. Using flow cytometric analysis of BM from new AA patients and from those recovering after immunosuppressive therapy, we determined that the numbers of CD34+ and CD33+ cells were markedly decreased in AA. Although PB neutrophil counts did not correlate with BM CD34+ cell numbers in acute disease, there was an association between the overall severity of the disease and the degree of CD34+ cell reduction. A decrease in BM CD33+ cells was a common finding in MDS patients, but reduction in CD34+ cells was found only in some hypoplastic MDS cases. Sorting experiments demonstrated lower plating efficiency for purified CD34+ cells from AA BM in comparison to controls. Thus, diminished colony formation of total BM appeared to result from both quantitative and qualitative defects. Based on the association between increased cycling and c-kit receptor expression on CD34+ cells, we found that the mitotically active CD34+ cells bearing the c-kit antigen were reduced in AA. With clinical improvement, CD34+ and CD33+ cells increased in correlation with PB parameters, but they did not return to normal values. Sorted CD34+ cells from recovered patents showed improved plating efficiency.(ABSTRACT TRUNCATED AT 250 WORDS)
Cellular Titin Localization in Stress Fibers and Interaction with Myosin II Filaments In Vitro

We previously discovered a cellular isoform of titin (originally named T-protein) colocalized with myosin II in the terminal web domain of the chicken intestinal epithelial cell brush border cytoskeleton (Eilertsen, K.J., and T.C.S. Keller. 1992. J. Cell Biol. 119:549-557). Here, we demonstrate that cellular titin also colocalizes with myosin II filaments in stress fibers and organizes a similar array of myosin II filaments in vitro. To investigate interactions between cellular titin and myosin in vitro, we purified both proteins from isolated intestinal epithelial cell brush borders by a combination of gel filtration and hydroxyapatite column chromatography. Electron microscopy of brush border myosin bipolar filaments assembled in the presence and absence of cellular titin revealed a cellular titin-dependent side-by-side and end-to-end alignment of the filaments into highly ordered arrays. Immunogold labeling confirmed cellular titin association with the filament arrays. Under similar assembly conditions, purified chicken pectoralis muscle titin formed much less regular aggregates of muscle myosin bipolar filaments. Sucrose density gradient analyses of both cellular and muscle titin-myosin supramolecular arrays demonstrated that the cellular titin and myosin isoforms coassembled with a myosin/titin ratio of approximately 25:1, whereas the muscle isoforms coassembled with a myosin:titin ratio of approximately 38:1. No coassembly aggregates were found when cellular myosin was assembled in the presence of muscle titin or when muscle myosin was assembled in the presence of cellular titin. Our results demonstrate that cellular titin can organize an isoform-specific association of myosin II bipolar filaments and support the possibility that cellular titin is a key organizing component of the brush border and other myosin II-containing cytoskeletal structures including stress fibers.
Benzoyl Peroxide Increases UVA-Induced Plasma Membrane Damage and Lipid Oxidation in Murine Leukemia L1210 Cells

Ultraviolet A radiation induces oxidative stress and cell damage. The purpose of this investigation was to examine whether ultraviolet A-induced cell injury was amplified by the presence of a non-ultraviolet A absorbing molecule capable of generating free radicals. Benzoyl peroxide was used as a lipid soluble potential radical-generating agent. Plasma membrane permeability assessed by trypan blue uptake was used to measure cell damage in murine leukemia L1210 cells. Cells were irradiated with a pulsed Nd/YAG laser at 355 nm using 0-160 J per cm2. The ratio of the fluence-response slope in the presence of 40 microM benzoyl peroxide to that of irradiated controls was 4.3 +/- 2.6. Benzoyl peroxide alone or benzoyl peroxide added after irradiation did not cause increased trypan blue uptake. The ratio of the fluence-response slopes in the presence of 40 microM benzoyl peroxide to that of irradiated controls was 4.7 +/- 1.4 when cells were irradiated (0-43 J per cm2) with a xenon lamp, filtered to remove wavelengths 34 J per cm2. The increased trypan blue uptake and thiobarbituric acid reactive substances were inhibited by butylated hydroxytoluene. These results suggest that agents not absorbing ultraviolet A radiation may enhance ultraviolet A-initiated oxidative stress in cells.
Soil enzyme activities after 1500 years of terrace agriculture in the Colca Valley, Peru

Abstract Long-term productivity and conservation of soils is critical for sustaining agricultural ecosystems. Long-term sites can provide important information about the effects of soil management practices on soil properties but there are relatively few such sites available worldwide. The Colca Valley of Peru provided a unique opportunity to study the effects of 1500 years of cultivation on Mollisols. The specific objective of the work reported was to determine the effects of cultivation at this site on soil enzyme activity as an index of soil biology and biochemistry. The study compared three key soil enzyme activities (phosphatase, β-glucosidase, and amidase) in presently cultivated and abandoned agricultural terraces, and matched uncultivated soils. Results showed that levels of organic matter, nitrogen and phosphorus were greater in agricultural than uncultivated soils. Unlike temperate regions where monoculture, intensive tillage and/or inorganic fertilizer practices have depressed soil enzyme activities, cultivated Colca soils have maintained similar or higher activities than the uncultivated/native soils. Maintenance of enzyme activities over hundreds of years in agricultural soils is partly attributed to traditional management practices including rotations with legumes, additions of animal manures, and minimum tillage.
How Metallic are Small Sodium Clusters

Cryogenic cluster beam experiments have provided crucial insights into the evolution of the metallic state from the atom to the bulk. Surprisingly, one of the most fundamental metallic properties, the ability of a metal to efficiently screen electric fields, is still poorly understood in small clusters. Theory has predicted that many small Na clusters are unable to screen charge inhomogeneities and thus have permanent dipole moments. High precision electric deflection experiments on cryogenically cooled ${\mathrm{Na}}_{N}$ ($Nl200$) clusters show that the electric dipole moments are at least an order of magnitude smaller than predicted, and are consistent with zero, as expected for a metal. The polarizabilities of Na clusters also show metal sphere behavior, with fine size oscillations caused by the shell structure.
Particle size control and self-assembly processes in novel colloids of nanocrystalline manganese oxide

The synthesis of semiconducting nanocrystals of manganese oxide of controlled sizes and their manipulation to form ordered arrays is described. Nanocrystalline mixed-valent manganese oxides have been prepared as colloidal solutions via reduction of tetraalkylammonium (methyl, ethyl, propyl, and butyl) permanganate salts in aqueous solutions with 2-butanol and ethanol. Reduction with the poorly water miscible 2-butanol produces aqueous colloids for the methyl, ethyl, and propyl systems, whereas 2-butanol colloids are produced for the butyl system. The colloids are reddish-brown, have an average manganese oxidation state of 3.70−3.79, and have been prepared in manganese concentrations up to 0.57 M. The sols will gel upon aging, and the gel time depends on the cation, the amount of alcohol, the temperature, and the concentration of manganese. Small angle neutron scattering (SANS) data indicate that the particles are disklike in shape with radii in the range 20−80 A and are largely unassociated in solution. T...
Long-Term Follow-Up and Response to Chemotherapy in Patients With Light-Chain Deposition Disease

Nineteen patients with light-chain deposition disease (LCDD) were studied retrospectively. This report presents data on long-term patient and renal survival and the response to intermittent administration of melphalan and prednisone. Immunoelectrophoresis or immunofixation demonstrated a monoclonal protein in the serum of 78% and in the urine of 84% of the patients; 16% had no demonstrable monoclonal protein in serum or urine. The median age at presentation was 51 years (range, 37 to 77 years). Twelve (63%) of the patients had a monoclonal protein of undetermined significance without evidence of myeloma. The typical glomerular lesion was a diffuse mesangial nodular lesion that was positive for periodic acid-Schiff (PAS) stain with acute and chronic tubulointerstitial changes. Fifteen patients had kappa light-chain deposition and four had lambda light-chain deposition. Five-year actuarial patient survival and survival free of end-stage renal disease were 70% and 37%, respectively. Seventeen patients received melphalan and prednisone, and one patient received chlorambucil and prednisone. All of the patients had some impairment of renal function at presentation, and 58% had a serum creatinine concentration greater than 354 mumol/L (4.0 mg/dL). There was either stabilization or improvement in renal function after chemotherapy in five of eight patients who had a serum creatinine concentration less than 354 mumol/L (4.0 mg/dL) at the initiation of therapy. Of the 11 patients with a high serum creatinine concentration (greater than 354 mumol/dL [4.0 mg/dL]), 82% progressed to end-stage renal disease despite therapy. Follow-up urine protein studies demonstrated at least a 50% decrease in urine protein excretion in five of 15 patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Identification of β‐sitosterol, campesterol, and stigmasterol in human serum

The presence of 3 plant sterols, β-sitosterol, campesterol, and stigmasterol, has been demonstrated in the serum from 2 patients with β-sitosterolemia and xanthomatosis.
Effect of prenatal exposure to ethanol on the development of cerebral cortex: I. Neuronal generation.

Prenatal exposure to ethanol causes profound disruptions in the development of the cerebral cortex. Therefore, the effect of in utero ethanol exposure on the generation of neurons was determined. Pregnant rats were fed a liquid diet in which ethanol constituted 37.5% of the total caloric content (Et) or pair-fed an isocaloric control diet (Ct) from gestational day (GD) 6 to the day of birth. The time of origin of cortical neurons was determined in the mature pups of females injected with (3H)thymidine on one day during the period from GD 10 to the day of birth. The brains were processed by standard autoradiographic techniques. Ethanol exposure produced multiple defects in neuronal ontogeny. The period of generation was 1-2 days later for Et-treated rats than for rats exposed prenatally to either control diet. Moreover, the generation period was 1-2 days longer in Et-treated rats. The numbers of neurons generated on a specific day was altered; from GD 12-19 significantly fewer neurons were generated in Et-treated rats than in Ct-treated rats, whereas after GD 19 more neurons were born. The distribution of neurons generated on a specific day was disrupted; most notable was the distribution of late-generated neurons in deep cortex ofmore » Et-treated rats rather than in superficial cortex as they are in controls. Cortical neurons in Et-treated rats tended to be smaller than in Ct-treated rats, particularly early generated neurons in deep cortex. The late-generated neurons in Et-treated rats were of similar size to those in Ct-treated rats despite their abnormal position in deep cortex. Neurons in Ct-treated rats tended to be rounder than those in Et-treated rats which were more polarized in the radial orientation.« less
Milk Fat Depression and Rumination Stimulation

Abstract Stimulating rumination by feeding polypropylene ribbon had no effect in alleviating milk fat depression. In two experiments with six cows in each, milk fat depression was produced by feeding a ground pelleted hay with concentrates and limited long hay. Feeding this ration resulted in a large reduction in time spent ruminating. Adding polypropylene ribbon, 5 cm long, returned rumination times to normal but had no effect on milk fat depression. Replacing ground hay with long hay returned both rumination times and milk fat to normal. The effect of long hay in preventing or reversing milk fat depression is due to factors other than its potential for stimulation of rumination.
Chemical and toxicological characterization of residential oil burner emissions: I. Yields and chemical characterization of extractables from combustion of No. 2 fuel oil at different Bacharach Smoke Numbers and firing cycles.

Particulates and complex organic mixtures were sampled from the exhaust of a flame retention head residential oil burner combusting No. 2 fuel oil at three firing conditions: continuous at Bacharac...
Oscillator strengths for the N2 second positive and N+2 first negative systems from observations of shock layers about hypersonic projectiles

Electronic oscillator strengths for nitrogen second positive and nitrogen first negative systems from observations of shock layers about hypersonic projectiles
The Terrestrial Magnetosphere: A Half-Wave Rectifier of the Interplanetary Electric Field

A study of geomagnetic disturbances during 1967 and 1968, for which in situ solar wind observations are available, reveals that the magnetosphere acts as a half-wave rectifier of the interplanetary electric field. The rate of injection of energy into the magnetosphere, as inferred from the strength of the disturbance, is approximately linearly proportional to the component of the electric field from dawn to dusk but is effectively zero if the electricfield has a component from dusk to dawn.
Poly(methyl methacrylate) as a self-assembled gate dielectric for graphene field-effect transistors

We investigate poly(methyl methacrylate) (PMMA) as a low thermal budget organic gate dielectric for graphene field effect-transistors (GFETs) based on a simple process flow. We show that high temperature baking steps above the glass transition temperature (∼130 °C) can leave a self-assembled, thin PMMA film on graphene, where we get a gate dielectric almost for “free” without additional atomic layer deposition type steps. Electrical characterization of GFETs with PMMA as a gate dielectric yields a dielectric constant of k = 3.0. GFETs with thinner PMMA dielectrics have a lower dielectric constant due to decreased polarization arising from neutralization of dipoles and charged carriers as baking temperatures increase. The leakage through PMMA gate dielectric increases with decreasing dielectric thickness and increasing electric field. Unlike conventional high-k gate dielectrics, such low-k organic gate dielectrics are potentially attractive for devices such as the proposed Bilayer pseudoSpin Field-Effect Transistor or flexible high speed graphene electronics.
Assessment of the Nature and Status of the MBA Restructuring Trend.

Graduate business education initiated its first major reorganization in the early 1960s, in response to two critical reports produced in 1959. Now MBA programs are once again undergoing a radical r...
The adsorption of ethanol on silver clusters supported on alumina

Abstract The adsorption of ethanol on islands of Ag supported on a surface of Al 2 O 3 has been investigated utilizing both inelastic electron tunneling spectroscopy (IETS) to probe the vibrational structure of the adsorbed species, and transmission electron microscopy to characterize some of the physical properties of the solid surface. Results are reported for the number and average size of Ag clusters on the surface as the amount of Ag is varied up to a statistically-averaged coverage of approximately 10 A. Vibrational spectra are shown for saturation coverage of ethanol as a function of Ag coverage. Peak shifts expected to arise due to the difference in electronegativities between Al and Ag are observed for the surface ethoxide species which form upon adsorption.
Inter-relations between VB & MO theories for organic II-networks

Publisher Summary This chapter discusses the Valence-Bond (VB) and Molecular-Orbital (MO) theories—there are review and comparison of the two. A natural question concerns the possibility of mathematical inter-relations between these VB and MO theories, especially because each of them may be viewed to be based on rather disparate pictures: the VB picture being built from localized orbitals arranged into (one or more) correlated many-electron structures, whereas the MO picture is built from delocalized orbitals in a single uncorrelated (determinantal) structure. Each picture can be viewed as complementary. That is, each theoretical picture is viewed as naught but a different representation of the same underlying quantum reality. Attention is focused on the rather well studied such models for π-electron networks in neutral (that is; non-ionic) organic molecules. Some aspects of the questions about mathematical inter-relations concern the presentation in terms of molecular graphs, these being natural mathematical representations of the classic valence structures of molecules. Such a graph G consists firstly of sites corresponding to atomic π-centers and secondly of edges corresponding to bonds between pairs of atoms. The mathematical field of graph theory provides a natural framework for classic chemical bonding ideas of modern quantum chemistry, the simple VB and MO models for a particular molecule being entirely determined by their graphs. The general inter-relations considered between VB and MO models then can be expected to be expressed in terms of graph-theoretic language, for general classes of molecules. Both the simple VB and MO models for organic π-networks are quantum–mechanical models explicitly expressible in terms of their molecular graphs. The chapter discusses the Pauling–Wheland VB model, Heisenberg model, and Huckel MO model. There is discussion on MO-based elaborations and cross-derivations, Huckel rule, polymers and excitations, and the prospects of VB and MO theories.
Application of some general resonance relations to excitation function data

The usefulness of analyzing resonance excitation function data with a general relation is discussed and demonstrated. Inelastic scattering data over the 9.14 MeV anomaly in $sup 12$C+ proton is consistent with a doublet with equal or nearly equal resonance energies for the two levels. A relation describing the energy dependence of experimental quantities which involve the ratio of resonating cross sections is derived and applied to the case of spin- flip probabilities in inelastic scattering. (AIP)
Real-space coupled-oscillator approach to the radiative decay of conjugated polymers

The optical response of conjugated polymers is calculated using a one-dimensional tight-binding model with Coulomb interactions, and adopting the multipolar form for the electromagnetic field Hamiltonian. By formulating the problem using the reduced single-electron density matrix and its evolution in Liouville space, we obtain a real-space description for the elementary electronic excitations. A unified expression for the linear response including radiative decay, which is valid for arbitrary chain size compared with the optical wavelength, is described. For small sizes it shows exciton confinement effects on the radiative decay and for larger sizes it fully incorporates polariton effects.
A genre, collocational, and constructional analysis of RISK

Scholars of language have begun to explore the popular academic topic that is “risk” and to establish the viability of corpus linguistics for such analysis. We extend existing scholarship by analyzing the noun lemma RISK over the last two decades of contemporary American discourse with recourse to the Corpus of Contemporary American English . Using the corpus procedures of frequency analysis, concordance contextual analysis, collocational analysis, and a variation on distinctive-collexeme analysis, we revisit the often under-supported assertion that RISK is semantically negative, and then investigate the semantic potential for good risk , a phenomenon associated with economic and adventuring sectors. Data suggest that RISK is genre sensitive, predominantly negative, and heavily medical in shared meaning across genres, and further, that evidence for good risk is minimal. A phrase of interest in recent corpus work — RISK worth taking — is shown to be sensitive perhaps more to constructional constraints than to semantic prosody.
Dissipation and noise immunity in computation and communication

Reversible computers which carry out each step without discarding information can, in principle, dissipate arbitrarily small amounts of energy per step if the computation is carried out sufficiently slowly. This has caused a re-examination of energy requirements in communication and measurement. There also, it is only those steps that discard information which have a lower limit on energy consumption. Such steps can be avoided in the transmission of information.
Passive Biotelemetry by Frequency Keying

A novel method for passive biotelemetry is presented which has the advantages of greater range and the ability to telemeter bioelectric data compared to conventional passive telemetry approaches.
Saddam, Israel, and the Bomb: Nuclear Alarmism Justified?

Efforts to understand Saddam Hussein's strategic thought have long been hampered by the opacity and secrecy of the Baathist regime. Newly available, high-level Iraqi archival documentation demonstrates that in the late 1970s and early 1980s, Saddam viewed nuclear weapons through a fundamentally coercive, revisionist lens. He had long hoped to wage a grinding war of attrition against the Israeli state, and he believed that Iraqi acquisition of the bomb would neutralize Israeli nuclear threats, force the Jewish state to fight at the conventional level, and thereby allow Iraq and its Arab allies (with their larger economic and population base) to prosecute a prolonged war that would displace Israel from the territories occupied in 1967. These findings have implications for the existing theoretical literature on the causes and consequences of nuclear proliferation, as well as for the growing body of work on “nuclear alarmism.” The Iraqi case undermines the thesis that states proliferate primarily because of d...
Biofunctionalization of silicone polymers using poly(amidoamine) dendrimers and a mannose derivative for prolonged interference against pathogen colonization.

Despite numerous preventive strategies on bacterial adhesion, pathogenic biofilm formation remained the major cause of medical device-related infections. Bacterial interference is a promising strategy that uses pre-established biofilms of benign bacteria to serve as live, protective coating against pathogen colonization. However, the application of this strategy to silicone urinary catheters was hampered by low adherence of benign bacteria onto silicone materials. In this work, we present a general method for biofunctionalization of silicone (PDMS) as one of the most widely used materials for biomedical devices. We used mild CO2 plasma to activate PDMS surface followed by simple attachment of generation 5 (G5) poly(amidoamine) (PAMAM) dendrimers to generate an amino-terminated surface that were maintained even after storage in PBS buffer for 36 days. We then covalently attach a carboxy-terminated mannose derivative to the modified PDMS to promote the adherence of benign Escherichia coli 83972 expressing mannose-binding type 1 fimbriae. We demonstrated that dense, stable biofilms of E. coli 83972 could be established within 48 h on the mannose-coated PDMS. Significantly, this benign biofilm reduced the adherence of the uropathogenic Enterococcus faecalis by 104-fold after 72 h, while the benign bacteria on the unmodified substrate by only 5.5-fold.
Spin susceptibility and gap structure of the fractional-statistics gas

This paper establishes and tests procedures which can determine the electron energy gap of the high-temperature superconductors using the t-J model with spinon and holon quasiparticles obeying fractional statistics. A simpler problem with similar physics, the spin susceptibility spectrum of the spin-1/2 fractional-statistics gas, is studied. Interactions with the density oscillations of the system substantially decrease the spin gap to a value of (0.2\ifmmode\pm\else\textpm\fi{}0.2)\ensuremath{\Elzxh}${\mathrm{\ensuremath{\omega}}}_{\mathit{c}}$, much less than the mean-field value of \ensuremath{\Elzxh}${\mathrm{\ensuremath{\omega}}}_{\mathit{c}}$. The lower-few Landau levels remain visible, though broadened and shifted, in the spin susceptibility. As a check of the methods, the single-particle Green's function of the noninteracting Bose gas viewed in the fermionic representation, as computed by the same approximation scheme, agrees well with the exact results. The same mechanism would reduce the gap of the t-J model without eliminating it.
The Ethics of Academic Journal Editing

This paper amounts to a reply to Professor Donald G. Brown’s thoughtful comment on my “Ethical Issues in Journal Peer-Review”, which appeared in this journal.
Temporal and Spatial Patterns in Root Nitrogen Concentration and Root Decomposition in Relation to Prescribed Fire

This study examined the temporal and landscape-scale patterns of root nitrogen concentration [N], root decomposition and N release from decomposing roots in oak-hickory forest ecosystems in southern Ohio. Sampling was conducted in three watershed-scale treatment units with different prescribed burning regimes, and each of these treatment units was divided into xeric, intermediate and mesic landscape positions. Root [N] decreased through the growing season in live roots but increased in dead roots. Root [N] was significantly lower in the xeric landscape positions, but only during the driest parts of the growing season. There was no consistent effect of prescribed burning on live or dead root [N]. Where differences among landscape position were detected, live root [N] was greatest in the most mesic landscape positions whereas dead root [N] was greatest in relatively xeric landscape positions. Overall, an average of 70% of original mass was lost from root litterbags and 80% of total N was released over one year of decomposition, with no significant differences among burning treatments in the instantaneous decay rate (k) or rate of N release. There were no differences among landscape positions in root decay rate or N release, even though prior studies have demonstrated strong landscape-position effects on leaf litter decomposition in similar sites. Overall, mass loss and N release from root litter is rapid in these ecosystems and relatively unaffected by either landscape position or fire frequency.
Towards automatic visual obstacle avoidance

This report describes ongoing research on a working system which drives a vehicle through cluttered environments under computer control, guided by images perceived through an onboard television camera. The emphasis is on reliable and fast low level visual techniques which determine the existence and location of objects in the world, but do not identify them
Durable resistance: A key to sustainable management of pathogens and pests

This review briefly addresses what has been learned about resistance durability in recent years, as well as the questions that still remain. Molecular analyses of major gene interactions have potential to contribute to both breeding for resistance and improved understanding of virulence impacts on pathogen fitness. Though the molecular basis of quantitative resistance is less clear, substantial evidence has accumulated for the relative simplicity of inheritance. There is increasing evidence for specific interactions with quantitative resistance, though implications of this for durability are still unknown. Mechanisms by which resistance gene pyramids contribute to durability remain elusive, though ideas have been generated for identifying gene combinations that may be more durable. Though cultivar mixtures and related approaches have been used successfully, identifying the diseases and conditions that are most conducive to the use of diversity has been surprisingly difficult, and the selective influence of diversity on pathogen populations is complex. The importance of considering resistance durability in a landscape context has received increasing emphasis and is an important future area of research. Experimental systems are being developed to test resistance gene deployment strategies that previously could be addressed only with logic and observation. The value of molecular markers for identifying and pyramiding major genes is quite clear, but the successful use of quantitative trait loci (QTL) for marker-assisted selection of quantitative resistance will depend greatly on the degree to which the identified QTL are expressed in different genetic backgrounds. Transgenic approaches will likely provide opportunities for control of some recalcitrant pathogens, though issues of durability for transgenes are likely to be no different than other genes for resistance. The need for high quality phenotypic analysis and screening methodologies is a priority, and field-based studies are likely to remain of signal importance in the foreseeable future.
Lagrangian coherent structures and mixing in two-dimensional turbulence

Abstract We introduce a Lagrangian definition for the boundaries of coherent structures in two-dimensional turbulence. The boundaries are defined as material lines that are linearly stable or unstable for longer times than any of their neighbors. Such material lines are responsible for stretching and folding in the mixing of passive tracers. We derive an analytic criterion that can be used to extract coherent structures with high precision from numerical or experimental data sets. The criterion provides a rigorous link between the Lagrangian concept of hyperbolicity, the Okubo–Weiss criterion, and vortex boundaries. We apply the results to simulations of two-dimensional barotropic turbulence.
Comparison of protein active site structures for functional annotation of proteins and drug design

Rapid and accurate functional assignment of novel proteins is increasing in importance, given the completion of numerous genome sequencing projects and the vastly expanding list of unannotated proteins. Traditionally, global primary-sequence and structure comparisons have been used to determine putative function. These approaches, however, do not emphasize similarities in active site configurations that are fundamental to a protein's activity and highly conserved relative to the global and more variable structural features. The Comparison of Protein Active Site Structures (CPASS) database and software enable the comparison of experimentally identified ligand-binding sites to infer biological function and aid in drug discovery. The CPASS database comprises the ligand-defined active sites identified in the protein data bank, where the CPASS program compares these ligand-defined active sites to determine sequence and structural similarity without maintaining sequence connectivity. CPASS will compare any set of ligand-defined protein active sites, irrespective of the identity of the bound ligand.
Sampling-based nonholonomic motion planning in belief space via Dynamic Feedback Linearization-based FIRM

In roadmap-based methods, such as the Probabilistic Roadmap Method (PRM) in deterministic environments or the Feedback-based Information RoadMap (FIRM) in partially observable probabilistic environments, a stabilizing controller is needed to guarantee node reachability in state or belief space. In belief space, it has been shown that belief-node reachability can be achieved using stationary Linear Quadratic Gaussian (LQG) controllers, for linearly controllable systems. However, for nonholonomic systems such as a unicycle model, belief reachability is a challenge. In this paper, we construct a roadmap in information space, where the local planners in partially-observable space are constructed by utilizing a Kalman filter as an estimator along with a Dynamic Feedback Linearization-based (DFL-based) controller as the belief controller. As a consequence, the task of belief stabilization to pre-defined nodes in belief space is accomplished even for nonholonomic systems. Therefore, a query-independent roadmap is generated in belief space that preserves the “principle of optimality”, required in dynamic programming solvers. This method serves as an offline POMDP solver for motion planning in belief space, which can seamlessly take obstacles into account. Experimental results show the efficiency of both individual local planners and the overall planner over the information graph for a nonholonomic model.
Scheduling in IEEE 802.16e mobile WiMAX networks: key issues and a survey

Interest in broadband wireless access (BWA) has been growing due to increased user mobility and the need for data access at all times. IEEE 802.16e based WiMAX networks promise the best available quality of experience for mobile data service users. Unlike wireless LANs, WiMAX networks incorporate several quality of service (QoS) mechanisms at the Media Access Control (MAC) level for guaranteed services for data, voice and video. The problem of assuring QoS is basically that of how to allocate available resources among users in order to meet the QoS criteria such as delay, delay jitter and throughput requirements. IEEE standard does not include a standard scheduling mechanism and leaves it for implementer differentiation. Scheduling is, therefore, of special interest to all WiMAX equipment makers and service providers. This paper discusses the key issues and design factors to be considered for scheduler designers. In addition, we present an extensive survey of recent scheduling research. We classify the proposed mechanisms based on the use of channel conditions. The goals of scheduling are to achieve the optimal usage of resources, to assure the QoS guarantees, to maximize goodput and to minimize power consumption while ensuring feasible algorithm complexity and system scalability.
The Developing Social Context of Infant Helping in Two U.S. Samples.

Theories about the development of helping make different assumptions about infants’ everyday experiences. Yet little research has investigated early helping at home. Two studies investigated the presence, encouragement, and social reinforcement of helping in 11- to 25-month-old infants in U.S. middle-class families. In Study 1, 76 mothers provided descriptions of infant helping. Study 2 involved videotaping of naturalistic interactions in 51 families. From around the first birthday, most infants helped at home. Instances of helping were frequently accompanied by encouragement, thanking, or praising. Longitudinal and cross-sectional findings were consistent with the view that family members’ involvement contributes to infant helping, although the role of family members may depend on infant age. These findings have implications for theories and research about infant helping.
Filters for distortion-free two-band multirate filter banks

In this paper, conditions are given for a two-band multi-rate filter bank to be alias free and to have a unity frequency response. It is shown that the class of quadrature mirror filters (QMF's) that satisfies these conditions is quite limited. A class of filters which does satisfy these conditions is given, and a simple procedure for designing filters from this class is presented with an example.
In Vivo Activation of Protein Kinase A in Schizosaccharomyces pombe Requires Threonine Phosphorylation at Its Activation Loop and Is Dependent on PDK1

Phosphoinositide-dependent protein kinase 1 (PDK1) plays a central role in cellular signaling by phosphorylating members of the AGC family of kinases. This family includes protein kinase C (PKC), protein kinase B (PKB), p70/p90 ribosomal S6 kinases (RSK and S6K), and the catalytic subunit of cAMP-dependent protein kinase (PKA). Although PDK1 phosphorylates and activates PKC, PKB, and RSK in vivo, PDK1 regulation of PKA remains controversial. We isolated ksg1, the fission yeast ortholog of mammalian PDK1, as a suppressor of growth defects caused by loss of the stress-activated MAP kinase, Spc1. Here, we demonstrate that Ksg1 is required for activation of PKA. Cells containing the ksg1.12 thermolabile allele exhibit pleiotropic phenotypes, including the failure to arrest in G1 and an inability to conjugate. The ksg1.12 allele strongly suppresses defects associated with unregulated PKA. Pka1, the catalytic subunit of cAMP-dependent protein kinase, is phosphorylated in vivo at Thr-356, which is located in the activation loop of the kinase and corresponds to Thr-197 in mammalian PKA. Phosphorylation of Thr-356 is required for in vivo activation of Pka1 and is dependent upon Ksg1. These data provide experimental evidence that PKA is a physiological substrate for PDK1.
STRATEGY FOR ALTERNATIVE OCCUPANT VOLUME TESTING

This paper describes plans for a series of quasi-static compression tests of rail passenger equipment. These tests are designed to evaluate the strength of the occupant volume under static loading conditions. The research plan includes a detailed examination of the behavior of conventional equipment during the 800,000-pound buff strength test. The research will also include a demonstration of an alternative static test that is designed to load and test the occupant volume at a location other than the buff lugs. The alternative test will demonstrate a testing and evaluation method for the occupant volume strength of passenger rail cars that accounts for the collision load path through the occupant volume. Per current Federal Railroad Administration (FRA) regulations, all passenger cars must support an 800,000-pound static load applied to the car’s line of draft without undergoing permanent deformation. However, more operators are looking to introduce equipment built to foreign standards. Many international manufacturers are implementing alternative designs that make use of crash energy management design features, articulated truck designs that span two cars, and low floor designs. These changes in the form and function of the designs require alternative means of applying a compressive load to assess occupant volume strength. FRA has reviewed several proposed alternatively designed equipment under requests for waivers for specific corridors of operation. Because the number of requests has increased significantly, FRA is trying to establish reasonable alternative means for assessing adequate and equivalent occupant volume strength to conventional equipment. This paper proposes an alternative static test procedure that will provide a means of evaluating a similar level of occupant volume integrity and passenger protection during a collision. The test will allow for greater design variation for newer rail cars and cars built to foreign standards. For the alternative test, the load may be introduced through the available structure at the floor level and at the roof level. These loading locations will enable the load to be applied directly into key longitudinal members in the load path of collision loads through the occupant volume. Finite element models are used before testing to determine appropriate alternative load levels and locations. The test article is a modified Budd Pioneer car. No significant modifications are planned for the longitudinal members of the car, or for the occupant volume.
Ultrasonic effects on alveolar macrophages in suspension

Rabbit alveolar macrophages in suspension were exposed to 5 or 10 min of continuous 2-MHz ultrasound with 5, 10, and 15 W/cm2 spatial average intensities. Viability as determined by dye exclusion decreased with increasing intensity. Pressure experiments indicated that this was a result of acoustic cavitation. Ultrasound induced clumping of cells and often reduced membrane ruffling. Some cells were disintegrated. Cells that appeared to be otherwise intact had swollen mitochondria with ruptured cristae.