cssi/SciSciGPT-SciSciNet huggingface dataset:
Phloem mobility of xenobiotics. V. Structural requirements for phloem‐systemic pesticides

Remote and relatively inaccessible parts of plants such as roots and meristematic tissue can readily be reached by foliar-applied xenobiotics if the latter are capable of entering into and moving in the phloem Development of a passivetransport model provides a description of the time course of this movement and its dependence upon the physical properties of the chemical and the condition of the plant vascular system. The model so developed is used to formulate principles for rendering otherwise non-systemic xenobiotics phloem-mobile. These principles can be categorized according to the nature of the chemical modifications that facilitate phloem translocation. These modifications include (a) sugar conjugation, (b) acid functionalization, and (c) formation of quaternary salts from basic parents. The potential of these modifications to facilitate the phloem translocation of wide range of pesticides is discussed.
Smolign: A Spatial Motifs-Based Protein Multiple Structural Alignment Method

Availability of an effective tool for protein multiple structural alignment (MSTA) is essential for discovery and analysis of biologically significant structural motifs that can help solve functional annotation and drug design problems. Existing MSTA methods collect residue correspondences mostly through pairwise comparison of consecutive fragments, which can lead to suboptimal alignments, especially when the similarity among the proteins is low. We introduce a novel strategy based on: building a contact-window based motif library from the protein structural data, discovery and extension of common alignment seeds from this library, and optimal superimposition of multiple structures according to these alignment seeds by an enhanced partial order curve comparison method. The ability of our strategy to detect multiple correspondences simultaneously, to catch alignments globally, and to support flexible alignments, endorse a sensitive and robust automated algorithm that can expose similarities among protein structures even under low similarity conditions. Our method yields better alignment results compared to other popular MSTA methods, on several protein structure data sets that span various structural folds and represent different protein similarity levels. A web-based alignment tool, a downloadable executable, and detailed alignment results for the data sets used here are available at http://sacan.biomed. drexel.edu/Smolign and http://bio.cse.ohio-state.edu/Smolign.
Cyclonic ring formation at the polar front in the Drake Passage

THE first summary of geographical locations of the antarctic convergence (polar front) by Mackintosh1 showed that >50% of the instantaneous locations of the front differed from the mean location by as much as ±50 km. Early hydrographic section work could not resolve the temporal or spatial fluctuations in the horizontal structure of the front. During FDRAKE 75 Gordon2 observed comparable fluctuations in the frontal position in the Scotia Sea but again the spacing between sections was too wide. During FDRAKE 76 (refs 3, 4 and T. M. Joyce et al., unpublished) the small scale structure of the polar front was studied in the Drake Passage. Two ships, the RV Thompson (University of Washington) and the Chilean naval vessel AGS Yelcho, combined efforts in the program which took place during the onset of the austral autumn. We describe here the evolution of the polar front between February 29 and April 5, 1976, a time span of ∼5 weeks.
A generalized reduced‐gravity ocean model

Abstract A major difficulty with two‐layer ocean models, except in the linear approximation, is encountered in situations where the interface intersects the seabed. For the single mode, reduced‐gravity version it is assumed that a passive deep lower layer exists everywhere, which in fact precludes any influence by bathymetry. These restrictions can be removed by employing a realistic continuous density stratification. Discussed here is a generalized, equivalent barotropic model in isopycnic coordinates that is based on the gravest vertical structure function E(σ) for current determined by the global, levelled‐state density distribution. The eigenvalue problem employs a rigid‐lid condition at the sea surface and requires E = 0 (a vanishing current) at the seabed for each local depth h. The gravest mode has monotonie E(σ) and an associated eigencelerity that is typical of a first baroclinic mode. Both the structure function and the celerity (hence the Rossby deformation radius) depend on the local depth h. ...
Low absolute mutagenic efficiency but high cytotoxicity of a non-bay region diol epoxide derived from benzo[a]pyrene

Abstract Insights into the mechanisms of chemical carcinogenesis can sometimes be gained by comparing the effects of closely related chemicals which differ in carcinogenic potency. We have treated Chinese hamster ovary (CHO) cells with a non-carcinogenic metabolite of benzo[ a ]pyrene, 9 r ,10 t -dihydroxy-7 c ,8 c -oxy-7,8,9,10-tetrahydrobenzo[ a ]pyrene (BPDE-III), and measured the formation and persistence of DNA adducts. We have correlated this binding data with cytotoxicity and mutagenicity in a DNA-repair-proficient CHO cell line (AT3-2) and in two derived lines, UVL-1 and UVL-10, which are unable to repair bulky DNA adducts. These data are compared with similar studies of the effects of the carcinogenic metabolite, 7 r ,8 t -dihydroxy-9 t ,10 t -oxy-7,8,9,10-tetrahydrobenzo[ a ]pyrene (BPDE-I). Synchronous fluorescence spectroscopy was used to measure the levels of BPDE-III-DNA adducts in treated cells. Adduct levels increased linearly with dose, but the absolute binding levels were about 30-fold lower than in comparable incubations with BPDE-I. Measurements of the removal of adducts derived from these two diol epoxides indicated no significant difference in the rate of repair measured 24 h post-treatment. When cells were treated with increasing doses of BPDE-III, survival curves were obtained which exhibited a shoulder region at low doses and an exponential decrease in plating efficiency at higher doses. By comparison of the D 0 's, the DNA-repair-deficient cell lines were found to be 4–5 fold more sensitive to the killing effects of BPDE-III than were the repair-proficient AT3-2 cells. Mutants at the APRT and HPRT loci were selected 1 week after treatment with BPDE-III at doses which resulted in > 10% survival. Mutant frequencies at both loci were found to increase linearly with dose. In the DNA-repair-deficient cells, both the HPRT and APRT loci were hypermutable, giving 9–15-fold higher mutant fractions in UVL-1 and UVL-10 than in AT3-2 cells at equal initial doses. When we compared the mutational efficiency of BPDE-III at both loci in AT3-2 cells (the mutant frequency in mutants/10 6 survivors at a dose which results in 1 adduct per 10 6 base pairs) with out previous studies of BPDE-I, we found that BPDE-III was 4–5 times less efficient as a mutagen than BPDE-I. However, a similar comparison of cytotoxic efficiency on a per adduct formed basis, revealed that BPDE-III was 2–3-fold more effective than BPDE-I. Since we have found no difference in the rate of removal of BPDE-I and BPDE-III adducts, these data suggest that BPDE-III adducts are inherently less mutagenic but more cytotoxic than are BPDE-I adducts.
The Management of Complications of Small Joint Arthrodesis and Arthroplasty

Arthrodesis and arthroplasty are surgical options used for the management of pain, stiffness, deformity, and instability related to arthritis and traumatic injury of the small joints of the hand. Arthrodesis and arthroplasty come with a risk of postoperative infection. Superficial soft tissue infections can often be managed with oral antibiotics alone. Deep infections and osteomyelitis frequently require removal of hardware in addition to antibiotics and may require surgical revision once the infection is cleared. Selection of the most appropriate revision technique depends on the underlying cause of the initial failure, patients' functional and outcome needs, and surgeon preference.
Nanoimprinted plasmonic nanocavity arrays

We demonstrate the resonant absorption of visible light with plasmonic nanocavity arrays fabricated by resistless nanoimprinting in metal (RNIM). The nanocavities are efficiently excited using normally incident light, and numerical simulations confirm the experimental data.
Fast, < 1 Nanosecond, Thermo-Optic Phase Shifters and Switches in SOI

Directly heated silicon-waveguide thermal Mach-Zehnder switches have switching times < 50 ns and a switching power from 0.1 to 5.5 mW. Modeling indicates that thermal switching times < 1 ns can be obtained with powers less than that required by other photonic integrated circuit compatible technologies.
Compliance With Food Safety Recommendations Among University Undergraduates: Application of the Health Belief Model

Compliance with food safety recommendations was assessed among 357 university undergraduates, 112 males (31%) and 245 females (69%), in the context of the health belief model. Concerning meats, 87% of the students complied with purchasing, 75% with storage, and 42% with preparation recommendations often/always. Compliance was high with recommended purchasing (96%) and storage (99%) practices for raw eggs, but only 55% of students prepared eggs safely. Overall, the health belief model was a poor predictor of compliance with food-safety recommendations. Findings suggest that college students would benefit from interventions focusing on the causes of microbial food contamination and those that assist them in overcoming perceived barriers to adopting safe food-handling practices. Also, validated instruments are needed to help family and consumer sciences educators identify college students who are noncompliant with food-safety recommendations.
Chairs' report on Twenty-First ACM Symposium on Operating Systems Principles

The 21st ACM Symposium on Operating Systems Principles (SOSP 2007) was held at the Skamania Lodge in Stevenson, Washington, USA from October 14th to October 17th 2007. The conference site is located in the Columbia River Gorge National Scenic Area, a spectacular canyon along the border between Oregon and Washington States in the Pacific Northwest, where the Columbia River cuts through the Cascades mountain range. Delegates were treated to breathtaking views of the gorge and mountains from the lodge's rustic and warm common areas and the weather cooperated for the arrival and early parts of the conference, though the rains came in force in the latter part of the conference.
THE RELATION OF THYROXINE TO TOTAL IODINE IN THE THYROID GLAND

The work of many investigators has made it clear that 90 per cent or more of the iodine in the normal thyroid gland is present in organic combination. This organic iodine, according to Harington (1933), can be completely accounted for by thyroxine and diiodotyrosine. These two compounds do not normally exist free in the gland but can be isolated after suitable hydrolysis of the thyroid protein. Various values have heretofore been reported for the proportions of thyroxine and diiodotyrosine present in thyroid tissue. Thus, by an acid separation, Harington and Randall (1929) obtained values of 40–50 for the ratio of thyroxine to total iodine. Similar values were found by others who employed their method (Rotter and Soos, 1933; Dey, 1945). Subsequently, Leland and Foster (1932), who used butyl alcohol for the extraction of thyroxine from an alkaline hydrolysate of the thyroid, reported that only 25 per cent of the iodine of the gland is present as thyroxine.
2-year tracking of children's fruit and vegetable intake.

Abstract Objective To evaluate the tracking of children's fruit and vegetable intake over 2 years. Design Children in the control group from the Gimme 5 nutrition education intervention trial completed three 7-day food diaries once a year in 1994, 1995, and 1996, beginning when they were in third grade. Subjects Five hundred sixty-one students from public elementary schools. Statistical analyses performed Tracking was examined through correlation of fruit and vegetable servings over the 2 years as well as the percent of subjects remaining in the same or adjacent quintiles of fruit and vegetable intake, using the κ statistic. Results Tracking of fruit and vegetable intake was fair to moderate over the 2 years. One-year correlations for total fruit and vegetable servings were .37 for boys and .46 for girls; 2-year correlations were .48 for boys and .40 for girls. κ values for remaining in the same quintile generally exceeded chance rates only for the top and bottom quintiles. No values exceeded .50. Application/conclusion The drift in ranking may have been a result of true changes in fruit and vegetable intake or measurement error (ie, inability to accurately assess actual intake). If this drift reflects true change, it may be difficult for nutrition education programs targeting this age group to demonstrate long-term behavioral effects on fruit and vegetable intake. If the drift is the result of measurement limitations, improved dietary assessment may yield stronger tracking. J Am Diet Assoc. 1998;98:785–789 .
Phase Retrieval for an Undersampled Thermal Infrared System

Phase retrieval was used on an undersampled, thermal infrared system to estimate focal plane displacement (defocus) across the field of view. We compare phase-retrieval estimated defocus values to those obtained using an independent technique.
Undiagnosed Tuberculosis in a General Hospital

Tuberculosis occasionally appears in an obscure form. Six patients are presented in whom the diagnosis was made either at autopsy or after an exploratory laparotomy. The disease had remained undiagnosed because of the paucity of clinical and roentgenologic findings referable to the lungs, an indeterminate tuberculin skin reaction and the misinterpretation of the so-called “inactive fibrotic scars.” To improve the diagnostic accuracy, repeated skin testing, cultures of liver and bone marrow biopsies and surgical specimens should be more widely used. A therapeutic trial with antituberculosis drugs is a useful diagnostic test in prolonged unexplained fevers.
Multigraphs with Δ ≥ 3 are Totally-(2Δ−1)-Choosable

The total graph T(G) of a multigraph G has as its vertices the set of edges and vertices of G and has an edge between two vertices if their corresponding elements are either adjacent or incident in G. We show that if G has maximum degree Δ(G), then T(G) is (2Δ(G) − 1)-choosable. We give a linear-time algorithm that produces such a coloring. The best previous general upper bound for Δ(G) > 3 was $$\lfloor{\frac{3}{2}\Delta(G)+2 \rfloor}$$, by Borodin et al. When Δ(G) = 4, our algorithm gives a better upper bound. When Δ(G)∈{3,5,6}, our algorithm matches the best known bound. However, because our algorithm is significantly simpler, it runs in linear time (unlike the algorithm of Borodin et al.).
Breast Cancer Detected on an Incident (Second or Subsequent) Round of Screening MRI: MRI Features of False-Negative Cases

OBJECTIVE. The purpose of this article is to evaluate the nature of breast cancers detected in the incident round of screening MRI to determine MRI features of early breast cancer. MATERIALS AND METHODS. From 2003 to 2012, there were 16 incident breast cancers in 15 patients on screening MRI, including nine cancers that were retrospectively identifiable on the prior MRI (false-negative [FN] cancers at prior screening examination). We evaluated the BI-RADS features of these incident cancers in previous and current MRI scans. RESULTS. Of 16 incident cancers, there were 11 mass lesions (69%), three foci (19%), and two nonmasslike enhancement lesions (13%). Of the nine FN cancers (five foci, two masses, and two nonmasslike enhancement lesions), all showed increases in size on the current examination (median, 80% increase); four lesions showed rapid uptake kinetics on prior examinations, and five lesions showed a change in kinetic pattern from slow to rapid uptake. Among the five foci, one focus was isolated a...
The Impact of the Core Transformation Process on Spirituality, Symptom Experience, and Psychological Maturity in a Mixed Age Sample in India: A Pilot Study

Research indicates that spiritual and religious constructs have the potential to influence a broad range of outcomes such as health, well-being, and meaning, both positively and negatively. This study looked at the effect of an under studied psycho-spiritual approach, Core Transformation (CT), in reducing symptoms and promoting well-being. This study also examined whether the impact of CT would be moderated by age, with older participants evidencing better outcomes. Participants from an Indian convenience sample (N = 189) ranging in age from 18 to 65 (M = 34) received group training in CT and completed a battery of measures pretest and 4 weeks post-training, which included personality, spirituality, and psychosocial outcomes scales. Repeated-measures MANOVAs indicated significant improvements over time for both spirituality and symptom experience. Partial correlation analyses, controlling for the predictive effects of personality, reaffirmed the incremental validity of Spiritual Transcendence and religious variables in predicting symptom change and outcome ratings. CT did not appear to effect participants levels of psychological maturity. Age was not found to mediate any of these relationships, indicating the age universality of CT’s therapeutic effects.
Laser skin welding: in vivo tensile strength and wound healing results.

Background and Objective Laser skin welding was investigated as a general model for laser tissue closure. Scanned delivery of near-infrared laser radiation in combination with a dye can produce strong welds with limited thermal damage. Study Design/Materials and Methods Two-centimeter-long, full-thickness incisions were made on the backs of guinea pigs. Wounds were closed either by laser welding or sutures and then biopsied at 0, 3, 6, 10, 14, 21, and 28 days postoperatively. Welding was achieved by using continuous-wave, 1.06-μm, Nd:YAG laser radiation scanned over the incisions to produce a dwell time of ∼80 msec. The cooling time between scans was fixed at 8 seconds. A 4-mm-diameter laser spot was maintained during the experiments, and the power was kept constant at 10 W. The operation time was fixed at 10 minutes per incision. India ink was used as an absorber of the laser radiation at the weld site, and clamps were used temporarily to appose the incision edges. Results Acute weld strengths of 2.1 ± 0.7 kg/cm2 were significantly higher than suture apposition strengths of 0.4 ± 0.1 kg/cm2 (P < 0.01), and weld strengths continued to increase over time. Lateral thermal damage in the laser welds was limited to 200 ± 40 μm near the epidermal surface with less thermal damage deeper within the dermis. Conclusion Our welding technique produced higher weld strengths and less thermal damage than reported in previous skin welding studies and may represent an alternative to sutures. Lasers Surg. Med. 27:55–65, 2000. © 2000 Wiley-Liss, Inc.
The diverse functions of short-term plasticity components in synaptic computations

Short-term plasticity (STP) comprises several rapid synaptic processes that operate on millisecond-to-minute timescales and modulate synaptic efficacy in an activity-dependent manner. Facilitation and augmentation are two major STP components in central synapses that work to enhance synaptic strength, while various forms of short-term depression work to decrease it. These multiple components of STP interact to perform a variety of synaptic computations. Using a modeling approach in excitatory hippocampal synapses, we recently described the contributions of individual STP components to synaptic operations. In this mini-review, we summarize the recent findings that revealed a wide palette of functions that STP components play in neural operations and discuss their roles in information processing, working memory and decision making.
Aromatic cations from oxidative carbon-hydrogen bond cleavage in bimolecular carbon-carbon bond forming reactions.

Chromenes and isochromenes react quickly with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to form persistent aromatic oxocarbenium ions through oxidative carbon–hydrogen cleavage. This process is tolerant of electron-donating and electron-withdrawing groups on the benzene ring and additional substitution on the pyran ring. A variety of nucleophiles can be added to these cations to generate a diverse set of structures.
Mechanisms of hydrothermal crystallization of quartz at 250°C and 15 kbar

Oxygen isotopic exchange between quartz and water, using a novel technique in which both 18O/16O and 17O/16O fractionations were measured, yielded an equilibrium fractionation Δ18 = 9.0 at 250°C and 15 kbar. The reaction proceeds predominantly by solution of fine grains and growth of larger grains. Exchange by solid-state diffusion is immeasurably slow at this temperature. Under the same experimental conditions, cristobalite behaves quite differently, becoming transformed to sub-micron quartz crystals in a few minutes. The phase transformation is accompanied by a kinetic isotope effect yielding quartz in isotopic disequilibrium with water. It is possible that such disequilibrium products are also formed in other experiments involving phase transitions or mineral syntheses.
Tortuosity of the vertebral artery resulting in vertebral erosion.

Abstract Objective: To discuss the case of a patient with unilateral vertebral artery tortuosity and dilatation resulting in vertebral body and transverse foramen erosion. An emphasis is placed on diagnostic imaging. Clinical Features: A 45-year-old man had a frozen shoulder and headaches. Previous arm pain, numbness, and a cold extremity were the result of occlusion of the subclavian artery and had been treated with a subclavian-carotid bypass procedure. Intervention and Outcome: As a result of the angiographic detection of the left vertebral artery dilatation and tortuosity and the concomitant hypoplastic right vertebral artery, high-velocity, low-amplitude manipulation of the cervical spine was contraindicated. However, the patient's symptoms were not related to these findings. Alternatively, low-force manipulation of the cervical spine, shoulder range of motion and muscle techniques were used, and the patient's symptoms diminished significantly with improved shoulder range of motion. Conclusion: Clinicians need to be alert to clinical presentations and appropriate imaging protocols in cases of suggested vertebral artery anomaly. (J Manipulative Phsyiol Ther 2000;23:48–51)
The Na+/H+ exchanger in transitional cells of the inner ear

Abstract The cytosolic pH (pH i ) of transitional cells from the ampulla of the gerbil was measured micro-fluorometrically with the pH-sensitive dye 2′,7′-bicarboxyethyl-5(6)-carboxyfluorescein (BCECF) to assess the possible contribution of a Na + /H + exchanger to the regulation of H i . All experiments were conducted in virtually HCO 3 − free solutions. Under control conditions, pH i was 7.19 and addition of 10 −5 M ethylisopropylamiloride (EIPA), a blocker of Na + /H + exchange, caused a small but significant acidification of pH i . A transient exposure to 21.4 mM NH 4 Cl caused a rapid cytosolic alkalinization followed by a brisk acidification and prompt recovery of pH i to its control value. The cytosolic buffer capacity (B i ) was determined in the absence of Na + from changes in pH i which were elicited by [NH + 4 ] steps. B i was 4.7 mM/pH at pH i 7.19 and varied with pH i . The initial net proton flux J H , representative of Na + /H + exchange activity, was calculated from the product of the initial rate of alkalinization after an NH + 4 -prepulse and B i at the corresponding pH i . J H was dependent on the extracellular Na + with an apparent K m of 64 mM, sensitive to the cytosolic [H + ] with an apparent K m of 2.7 ∗ 10 −7 M (i.e. pH 6.6), and inhibited by EIPA with an IC 50 of 5 ∗ 10 −7 M. These data suggest that transitional cells contain in the basolateral membrane a Na + /H + exchanger of the amiloride-sensitive subtype.
Rocket measurements of relativistic electrons: New features in fluxes, spectra and pitch angle distributions

Novel features are presented of precipitating relativistic electron fluxes measured on a spinning sounding rocket payload at midday between altitudes of 70 and 130 km in the auroral region. The sounding rocket was launched during a relativistic electron enhancement event of modest intensity. Electron fluxes were measured for a total of about 210 seconds at energies from 0.1 to 3.8 MeV, while pitch angle was sampled from 0 to 90 deg every spin cycle. Electrons with energies below about 0.2 MeV showed isotropic pitch angle distributions during most of the first 90 sec of data, while at higher energies the electrons had the highest fluxes near the mirroring angle (90 deg); when they occurred, the noted downward bursts were seen at all energies. The low-altitude fluxes are compared with those measured at geostationary orbit, and it is found that the low-altitude fluxes are much higher than expected from a simple mapping of a pancake distribution at high altitudes.
Unusual Current Perpendicular-to-Plane (CPP) Magnetoresistance (MR) for Thick Co Layers—Difference in MR for fcc and hcp Co

We report an unexpected difference in behavior of the CPP-MRs of double exchange-biased spin-valves, involving Permalloy (Py), Co, and Cu, when the Co layer is thin (tCo ? 20 nm) or thick (tCo ? 50 nm). Following Hehn et al., we attribute this difference to a change in direction of magnetization of the Co with increasing tCo, with the magnetization lying in-plane for thin Co layers (tCo ? 20 nm), but tilting partially out of plane for thick Co layers (tCo ? 50 nm) by adopting a multidomain structure containing equal areas of "up" and "down" domains. If our attribution is correct, this is the first example of a qualitative change in giant magnetoresistance due to a change in Co structure from mainly fcc to mainly hcp.
Copper Deposition onto Silicon by Galvanic Displacement: Effect of Silicon Dissolution Rate

The rates of Cu deposition onto rotating Si electrodes were measured to probe the effects of mass transfer, Cu 2+ reduction, and Si oxidation and dissolution on deposition dynamics. Cu deposition rates were proportional to CuSO 4 concentration and limited by Cu 2+ diffusion and subsequent reduction at high HF concentrations ([HF]/[CuSO 4 ] > 20). In contrast, Si dissolution limited film growth at low HF concentrations ([HF]/[CuSO 4 ] < 10), and HF - 2 was identified as the most active Si etchant. The observed effects of rotation rate indicate that mass transfer of Cu 2+ limits deposition rates, but mass transfer of HF does not. Open-circuit potential measurements and mixed-potential theory were used to develop a reaction-transport model that accurately predicts deposition rates over a broad range of Cu and HF concentrations. The structure of the films formed was probed by atomic force microscopy. The roughness of the Cu films decreased with increasing [HF]/[CuSO 4 ] ratios, as Si surfaces became less oxidized, and lateral connectivity between Cu nuclei increased.
An adaptive finite element solver for transient problems with moving bodies

The combination of adaptive remeshing techniques, flow solvers for transient problems with moving grids, and integrators for rigid body motion is presented. The resulting scheme allows the economic simulation of fully coupled fluid-rigid body interaction problems of arbitrary geometric complexity. Several results are given to demonstrate the capabilities developed.
Cognitive Flexibility, Communication Strategy, and Integrative Complexity in Groups: Public versus Private Reactions to Majority and Minority Status

Archival studies of political decision-making groups show that the public statements of policy makers in the majority are higher in integrative complexity than those of minority-faction or unanimous group members. However, whether these differences reflect policy makers' private thoughts, or their public impression management strategies, cannot be inferred using only data from the public record. The experiment reported here established that in freely interacting groups composed of majorities and minorities, this pattern is obtained under private communication conditions as well as in public statements. Results suggest that cognitive flexibility in response to influence from insiders, rather than communication strategies designed to influence outsiders, underlies the differences observed.
Advance Care Discussions: Pediatric Clinician Preparedness and Practices

Abstract Context Few data exist regarding clinician preparedness to participate in advance care discussions (ACD) and the practices surrounding these discussions for children with life-threatening conditions. Objectives We sought to understand pediatric clinician preparedness to participate in ACD and the practices surrounding these discussions. Methods A survey was administered to assess clinician attitudes and behaviors regarding ACD. Results Two hundred sixty-six clinicians (107 physicians and 159 nurses) responded to the survey (response rate 53.6%). Seventy-five percent of clinicians felt prepared to participate in ACD. Most clinicians believed they were prepared to express empathy (98.8%), discuss goals of care for an adolescent patient (90.3%), and elicit a parent's hopes (90.3%). Conversely, several felt unprepared to discuss resuscitation status with school-aged (59.7%) and adolescent (48.5%) patients and to conduct a family conference (39.5%). The most frequent topics addressed were: parents' understanding of the patient's illness (75.5%), primary goals of the parent (75.1%), and the parents' understanding of prognosis (71.1%). Conversely, the topics least commonly discussed were as follows: belief system of the patient/family (22.0%), patient's hopes (21.2%), and the patient's perceptions of his/her quality of life (19.8%). Notably, 40% of clinicians believe that caring for patients with poor prognoses is depressing, and this was more common among less-experienced clinicians (P = 0.048). Conclusion Many clinicians believe they are prepared to participate in ACD, but practices are not consistent with expert recommendations for optimal ACD. Educational interventions aimed at improving clinician knowledge, attitudes, and behavior, and greater clinician support may enhance health care provider ACD preparedness and skills.
Proton Probing of the Charybdotoxin Binding Site of Shaker K+ Channels

We have investigated the interaction of charybdotoxin (CTX) with Shaker K channels. We substituted a histidine residue for the wild-type phenylalanine (at position 425) in an inactivation-removed channel. The nature of the imidazole ring of the histidine provides the ability to change the charge on this amino acid side chain with solution hydrogen ion concentration. Wild-type, recombinant CTX blocked wild-type Shaker channels in a bimolecular fashion with a half-blocking concentration (Kd) of 650 nM (at a membrane potential of 0 mV). The F425H mutant channels were much more sensitive to CTX block with an apparent Kd (at pH 7.0) of 75 nM. Block of F425H but not wild-type channels was strongly pH sensitive. A pH change from 7 to 5.5 rendered the F425H channels >200-fold less sensitive to CTX. The pH dependence of CTX block was steeper than expected for inhibition produced by H+ ions binding to identical, independent sites. The data were consistent with H+ ions interacting with subunits of the channel homotetrameric structure. The in situ pK for the imidazole group on the histidine at channel position 425 was determined to be near 6.4 and the dissociation constant for binding of toxin to the unprotonated channel was near 50 nM. We estimate that the binding of a H+ ion to each subunit adds 0.8 kcal/mol or more of interaction energy with CTX. We used mutant toxins to test electrostatic and steric interactions between specific CTX residues and channel position 425. Our results are consistent with a model in which protons on F425H channel subunits interact with three positive charges on CTX at an effective distance 6–7 A from this channel position.
Influence of DC-link fluctuations on three-phase induction motor drives

Modern induction machine (IM) drives are subject to a variety of system perturbations, possibly compromising machine performance characteristics such as speed, torque, and load current. This paper presents a three-phase induction motor drive system with an active IGBT rectifier, i.e. an Active Front End (AFE). The AFE converts the AC line input into a controlled DC-link voltage which is then used as input into a three-phase IM drive, based on an IGBT converter. A reconfigurable IM drive, i.e. the inverter, is controlled by the conventional PWM and space vector PWM based methods. This paper investigates the influences of the DC-link variations on the IM drive under each of these modulation strategies. A simulated drive is verified via an experimental test bed, and is then used to further study more extreme DC-Link fluctuations; specifically, variations 10 percent above and below the experimental value of 670 V. Phase current and voltage THD and spectra will be calculated to evaluate the fluctuations influence on performance characteristics. This system will be verified based on the control system rapid prototyping environment of dSPACE.
Characterization of mature maize (Zea mays L.) root system architecture and complexity in a diverse set of Ex-PVP inbreds and hybrids

The mature root system is a vital plant organ, which is critical to plant performance. Commercial maize (Zea mays L.) breeding has resulted in a steady increase in plant performance over time, along with noticeable changes in above ground vegetative traits, but the corresponding changes in the root system are not presently known. In this study, roughly 2500 core root systems from field trials of a set of 10 diverse elite inbreds formerly protected by Plant Variety Protection plus B73 and Mo17 and the 66 diallel intercrosses among them were evaluated for root traits using high throughput image-based phenotyping. Overall root architecture was modeled by root angle (RA) and stem diameter (SD), while root complexity, the amount of root branching, was quantified using fractal analysis to obtain values for fractal dimension (FD) and fractal abundance (FA). For each trait, per se line effects were highly significant and the most important contributor to trait performance. Mid-parent heterosis and specific combining ability was also highly significant for FD, FA, and RA, while none of the traits showed significant general combining ability. The interaction between the environment and the additive line effect was also significant for all traits. Within the inbred and hybrid generations, FD and FA were highly correlated (rp ≥ 0.74), SD was moderately correlated to FD and FA (0.69 ≥ rp ≥ 0.48), while the correlation between RA and other traits was low (0.13 ≥ rp ≥ −0.40). Inbreds with contrasting effects on complexity and architecture traits were observed, suggesting that root complexity and architecture traits are inherited independently. A more comprehensive understanding of the maize root system and the way it interacts with the environment will be useful for defining adaptation to nutrient acquisition and tolerance to stress from drought and high plant densities, critical factors in the yield gains of modern hybrids.
A New Method to Enhance Contrast of Ultrathin Cryosections for Immunoelectron Microscopy

Adequate contrast of ultrathin cryosections is crucial for evaluating morphological detail to assess immunocytochemical localization at the electron microscopic level. We have developed a positive staining method for achieving contrast in ultrathin cryosections, from tissue fixed only in paraformaldehyde, that provides excellent contrast at the electron microscopic level.
Perirheic mixing and biogeochemical processing in flow‐through and backwater floodplain wetlands

Inundation hydrology and associated processes control biogeochemical processing in floodplains. To better understand how hydrologic connectivity, residence time, and intrafloodplain mixing vary in floodplain wetlands, we examined how water quality of two contrasting areas in the floodplain of the Atchafalaya River—a flow-through and a backwater wetland—responded to an annual flood pulse. Large, synoptic sampling campaigns occurred in both wetlands during the rising limb, peak, and falling limb of the hydrograph. Using a combination of conservative and reactive tracers, we inferred three dominant processes that occurred over the course of the flood pulse: flushing (rising limb), advective transport (peak), and organic matter accumulation (falling limb). Biogeochemistry of the two wetlands was similar during the peak while the river overflowed into both. However, during the rising and falling limbs, flow in the backwater wetland experienced much greater residence time. This led to the accumulation of dissolved organic matter and dissolved phosphorus. There were also elevated ratios of dissolved organic carbon to nitrate in the backwater wetland, suggesting nitrogen removal was limited by nitrate transported into the floodplain there. Collectively, our results suggest inclusion of a temporal component into the perirheic concept more fully describes inundation hydrology and biogeochemistry in large river floodplain.
Stability in a Denitrifying Fluidized Bed Reactor

This study evaluates changes in the microbial community structure and function of a pilot-scale denitrifying fluidized bed reactor during periods of constant operating conditions and periods of perturbation. The perturbations consisted of a shutdown period without feed, two disturbances in which biofilms were mechanically sheared from carrier particles, and a twofold step increase in feed nitrate concentration. In the absence of perturbations, nitrate removal was stable and consistently greater than 99%. The structure and dynamics of the microbial community were studied using cloning and sequencing techniques and terminal restriction fragment length polymorphism (T-RFLP) of the SSU rRNA gene. Under unperturbed operating conditions, stable function was accompanied by high constancy and low variability of community structure with the majority of terminal restriction fragments (T-RFs) appearing throughout operation at consistent relative abundances. Several of the consistently present T-RFs correlated with clone sequences closely related to Acidovorax (98% similarity), Dechloromonas (99% similarity), and Zoogloea (98% similarity), genera recently identified by molecular analyses of similar systems. Significant changes in community structure and function were not observed after the shutdown period. In contrast, following the increase in loading rate and the mechanical disturbances, new T-RFs appeared. After both mechanical disturbances, function and community structure recovered. However, function was much more resilient than community structure. The similarity of response to the mechanical disturbances despite differences in community structure and operating conditions suggests that flexible community structure and potentially the activity of minor members under nonperturbation conditions promotes system recovery.
Thermoplastic polyheterocycles. I: Polyalkylene-benzoxazoles†

Polyalkylenebenzoxazoles of high molecular weight (inherent viscosity values from 0.76 to 2.95) were prepared from 4,6-diaminoresorcinol dihydrochloride and aliphatic diacids in polyphosphoric acid by heating at 180 to 200°C for 3–5 h. Melting points of the polymers ranged from 148 to 423°C, depending on the length of the alkylene chain. Glass transition temperatures were relatively low, ranging from 50 to 100°C and did not show the pronounced odd/even effect noted for melting points. In all cases, rapid weight loss occurred above 400°C. No evidence for the formation of a molecular composite was observed in an attempt to prepare in situ a rod-like polybenzoxazole in a polyalkylenebenzoxazole.
Combined script and page orientation estimation using the Tesseract OCR engine

This paper proposes a simple but effective algorithm to estimate the script and dominant page orientation of the text contained in an image. A candidate set of shape classes for each script is generated using synthetically rendered text and used to train a fast shape classifier. At run time, the classifier is applied independently to connected components in the image for each possible orientation of the component, and the accumulated confidence scores are used to determine the best estimate of page orientation and script. Results demonstrate the effectiveness of the approach on a dataset of 1846 documents containing a diverse set of images in 14 scripts and any of four possible page orientations.A C++ implementation of this work will be made available in a future release of the open-source Tesseract OCR engine [1].
The egg industry of California and the USA in the 1990s: a survey of systems

Survey data collected by the University of California have quantified some current systems of commercial egg production in the USA as a whole and in the state of California. Specific comparisons are made. Respondents were asked to estimate certain changes in the egg production sector between the present time and the year 2000. These projections suggest: a continuing trend for contract production to decline in favour of company owned sites; some further increase in cage rearing; more attention to improved methods of handling manure and disposing of dead birds; and a continuing growth in the number of large scale in-line egg production complexes. The projection that the size of the USA layer population will increase by over 20% by the end of the decade is considered unlikely to happen.
An ultrastructural and histochemical study of rat atrial myocardium

A study was made of the ultrastructural and histochemical characteristics of atrial muscle cells. The myofibrils of these cells do not converge at the nuclear poles as in the ventricular cells, but leave large sarcoplasmic spaces in the central cores, which contain mitochondria, small amounts of rough-surfaced sarcoplasmic reticulum, free ribosomes and one or more well developed Golgi complexes. Numerous cytoplasmic granules, many of which are closely associated with the Golgi material, are present in these cells. These granules can be demonstrated in paraffin sections by the Bowie stain. The smooth-surfaced sarcoplasmic reticulum of atrial fibers consists of a meshwork of interconnected tubules which pass uninterruptedly from one sarcomere to another. No transverse dilatations or T tubules are present as in ventricular cells; however, there are numerous subsarcolemmal cisterns consisting of flattened dilatations of sarcoplasmic reticulum which lie in close proximity to the internal surface of the sarcolemma. There is considerable variation from one cell to another in the number and compactness of arrangement of the myofibrils, and in the abundance of other cellular components. On the basis of the above findings, we suggest that atrial muscle cells may have a secretory as well as a contractile function.
A graphical environment for interactive four-dimensional data navigation

We have designed a system for presenting and graphically navigating four-variable data in a four-dimensional Cartesian environment. With full translational and rotational freedom, the system provides a 4D scene that can be explored and understood interactively. The system presents a four-dimensional environment to the user as a collection of 3D slices. Volunteers explored and solved randomly-generated 4D mazes of increasing complexity and size by traversing them to the end. Their ability to solve mazes improved significantly with practice, reflecting an increasing ability to engage the 4D environment and demonstrating the viability of the system.
N-Ethylmaleimide-modified Hsp70 inhibits protein folding.

Hsp70 molecular chaperones facilitate protein folding and translocation by binding to hydrophobic regions of nascent or unfolded proteins, thereby preventing their aggregation. N-Ethylmaleimide (NEM) inhibits the ATPase and protein translocation-stimulating activities of the yeast Hsp70 Ssa1p by modifying its three cysteine residues, which are located in its ATPase domain. NEM alters the conformation of Ssa1p and disrupts the coupling between its nucleotide- and polypeptide-binding domains. Ssa1p and the yeast DnaJ homolog Ydj1p constitute a protein folding machinery of the yeast cytosol. Using firefly luciferase as a model protein to study chaperone-dependent protein refolding, we have found that NEM also inhibits the protein folding activity of Ssa1p. Interestingly, the NEM-modified protein (NEM-Ssa1p) is a potent inhibitor of protein folding. NEM-Ssa1p can prevent the aggregation of luciferase and stimulate the ATPase activity of Ssa1p suggesting that it acts as an inhibitor by binding to nonnative forms of luciferase and by competing with them for the polypeptide binding site of Ssa1p. NEM-Ssa1p inhibits Ssa1p/Ydj1p-dependent protein refolding at different stages indicating that the chaperones bind and release nonnative forms of luciferase multiple times before folding is completed.
Media Review Editor's Message

Editorial introduction from Carolyn O'Mahony, Media Review Editor, Journal of International Social Studies
Facts & Figuring: Network Structure & Performance in Information & Solution Spaces

Using data from a large laboratory experiment on problem solving in which we varied the structure of 16-person networks we investigate how an organization’s network structure may be constructed to optimize performance in complex problem- solving tasks. Problem solving involves both search for information and search for theories to make sense of that information. We show that the effect of network structure is opposite for these two equally important forms of search. Dense clustering encourages members of a network to generate more diverse information, but it also has the power to discourage the generation of diverse theories: clustering promotes exploration in information space, but decreases exploration in solution space. Previous research, tending to focus on only one of those two spaces, had produced inconsistent conclusions about the value of network clustering. By adopting an experimental platform on which information was measured separately from solutions, we were able to reconcile past contradictio...
The Use of Music with Hospitalized Infants and Toddlers: A Descriptive Study

This clinical study was conducted to examine the effectiveness of music in decreasing stress behaviors exhibited by hospitalized infants and toddlers. The sample consisted of 27 hospitalized infants and toddlers, ages 5 weeks to 36 months, who had demonstrated stress behaviors (defined as crying, throwing objects, absence of vocalization, lethargy, and/or body tension) during 15-minute observation sessions. Each subject was assigned to a music program implemented by a Registered Music Therapist (RMT) on the Child Life staff. Programming included relaxation, didactic games, movement, and songs. Sessions lasted from 15 minutes to 1 hour. During the sessions, the subjects were observed and their behaviors were recorded on a checklist. Results of the study indicated that music plus interaction with a music therapist effectively reduced stress-related behaviors.
Superoxide anion production by rabbit thoracic aorta: effect of endothelium-derived nitric oxide.

Rabbit thoracic aorta was assessed for the influence of the endothelium and nitric oxide (NO) on superoxide anion (SO) levels in the presence and absence of an inhibitor of superoxide dismutase. Ao...
Book reviews: Knowledge representation and commonsense reasoning: Reviews of four books

Ronald J. Brachman, Hector J. Levesque, Knowledge Representation and Reasoning, Morgan Kaufmann,ISBN 1558609326, 2004, 381 pages.Raymond Reiter, Knowledge in Action: Logical Foundations for Specifying and Implementing DynamicalSystems, MIT Press, ISBN 0262182181, 2001, 448 pages.Erik T. Mueller, Commonsense Reasoning, Morgan Kaufmann, ISBN 0123693888, 2006, 432 pages.Chitta Baral, Knowledge Representation, Reasoning and Declarative Problem Solving, Cambridge UniversityPress, ISBN 0521818028, 2003, 544 pages.