bluuebunny/crossref_metadata_2025 huggingface dataset:
On the use of the quasi-Gaussian entropy theory in the study of simulated dilute solutions
Authors: D’Abramo M. , D’Alessandro M. , Amadei Andrea
Published: March 2004

In a recent paper [M. D’Alessandro, M. D’Abramo, G. Brancato, A. Di Nola, and A. Amadei, J. Phys. Chem. B 106, 11843 (2002)] we showed how to combine molecular dynamics simulations with the quasi-Gaussian entropy theory, in order to model the statistical mechanics and thermodynamics of ionic (water) solutions. In this paper we extend the method to treat nonspherical solutes, describe more thoroughly its theoretical basis and apply it to a set of more complex solute molecules in water (i.e., water, methane, ethane, methanol, and ethanol). Results show that this approach can really provide an excellent theoretical description of solute–solvent systems over a wide range of temperatures.
Comparing the dynamical effects of symmetric and antisymmetric stretch excitation of methane in the Cl+CH4 reaction
Authors: Bechtel Hans A. , Camden Jon P. , Brown Davida J. Ankeny , Zare Richard N.
Published: March 2004

The effects of two nearly isoenergetic C–H stretching motions on the gas-phase reaction of atomic chlorine with methane are examined. First, a 1:4:9 mixture of Cl2, CH4, and He is coexpanded into a vacuum chamber. Then, either the antisymmetric stretch (ν3=3019 cm−1) of CH4 is prepared by direct infrared absorption or the infrared-inactive symmetric stretch (ν1=2917 cm−1) of CH4 is prepared by stimulated Raman pumping. Photolysis of Cl2 at 355 nm generates fast Cl atoms that initiate the reaction with a collision energy of 1290±175 cm−1 (0.16±0.02 eV). Finally, the nascent HCl or CH3 products are detected state-specifically via resonance enhanced multiphoton ionization and separated by mass in a time-of-flight spectrometer. We find that the rovibrational distributions and state-selected differential cross sections of the HCl and CH3 products from the two vibrationally excited reactions are nearly indistinguishable. Although Yoon et al. [J. Chem. Phys. 119, 9568 (2003)] report that the reactivities of these two different types of vibrational excitation are quite different, the present results indicate that the reactions of symmetric-stretch excited or antisymmetric-stretch excited methane with atomic chlorine follow closely related product pathways. Approximately 37% of the reaction products are formed in HCl(v=1,J) states with little rotational excitation. At low J states these products are sharply forward scattered, but become almost equally forward and backward scattered at higher J states. The remaining reaction products are formed in HCl(v=0,J) and have more rotational excitation. The HCl(v=0,J) products are predominantly back and side scattered. Measurements of the CH3 products indicate production of a non-negligible amount of umbrella bend excited methyl radicals primarily in coincidence with the HCl(v=0,J) products. The data are consistent with a model in which the impact parameter governs the scattering dynamics.
Coherent interactions in femtosecond transient grating
Authors: Park June-Sik , Joo Taiha
Published: March 2004

Transient grating of a dye in liquid has been measured as a function of the electronic coherence period. A diffractive beam splitter and a pair of wedge prisms are implemented to achieve precise spatial phase overlap and interferometrically accurate control of the time delay between the pump pulses. As the electronic coherence period is varied, coherent interactions lead to an enhancement or loss of the sharp feature in the transient grating signal near time zero, which is usually called coherent spike. Sensitivity of the transient grating signal to the solvation process also changes by the coherence time delay. All the features can be accounted for by invoking third-order nonlinear response functions. Numerical simulations have been performed to corroborate our description. This work identifies a major source of the coherent spike in the transient grating and transient absorption experiments. In addition, it allows us to propose a method that measures the solvation function more efficiently than conventional transient grating technique does.
Effects of solvation and core switching on the photoelectron angular distributions from (CO2)n− and (CO2)n−⋅H2O
Authors: Mabbs Richard , Surber Eric , Velarde Luis , Sanov Andrei
Published: March 2004

Photoelectron images are recorded in the photodetachment of two series of cluster anions, (CO2)n−, n=4–9 and (CO2)n−⋅H2O, n=2–7, with linearly polarized 400 nm light. The energetics of the observed photodetachment bands compare well with previous studies, showing evidence for switching between two anionic core structures: The CO2− monomer and covalent (CO2)2− dimer anions. The systematic study of photoelectron angular distributions (PADs) sheds light on the electronic structure of the different core anions and indicates that solvation by several CO2 molecules and/or one water molecule has only moderate effect on the excess-electron orbitals. The observed PAD character is reconciled with the symmetry properties of the parent molecular orbitals. The most intriguing result concerns the PADs showing remarkable similarities between the monomer and dimer anion cluster-core types. This observation is explained by treating the highest-occupied molecular orbital of the covalent dimer anion as a linear combination of two spatially separated monomeric orbitals.
Internal state distributions of fragment HCO via S and T1 pathways of glyoxal after photolysis in the ultraviolet region
Authors: Kao Chih Chieh , Ho Mei-Lin , Chen Ming-Wei , Lee Sheng-Jui , Chen I-Chia
Published: March 2004

The dynamics of photodissociation of glyoxal (HOC–COH) near the dissociation threshold on the triplet manifold are studied through measurement of distributions of nascent fragment HCO in various internal states. Three rotational levels 101*, 413*, and 321*+322* of vibrational state U (excitation wavelength ∼394.4 nm, origin at 25 331.865 cm−1) of glyoxal in state Ã 1Au and two other vibrational states at excitation wavelengths 390.33 and 382.65 nm are selected to produce fragment HCO. By means of fluorescence in the transition B̃ 2A′–X̃ 2A′ of HCO, we determined the relative populations of internal states of that fragment. Rotational states of product HCO up to N=26 and K=2 are populated, and bimodal distributions of these rotational states are observed for the photolysis wavelengths used in this work. The high rotational part of the distribution with average energy near values calculated on the basis of the statistical model—phase-space theory is assigned to arise from glyoxal on its S0 surface, and the low rotational part from the T1 surface with an exit barrier. After photolysis near the threshold region on the triplet surface, HCO arising from the T1 state appears to be a major component of products because these rotational levels 101*, 413*, and 32* of U state selected are gateway states with an enhanced rate of intersystem crossing.
Elastic behavior of short compact polymers
Authors: Sun Tingting , Zhang Linxi , Chen Jin , Shen Yu
Published: March 2004

In this paper, we investigate the elastic behaviors of short compact polymers using the enumeration calculation method and the HP model on a two-dimensional square lattice. Both the mean-square end-to-end distance 〈R2〉 and the ratio of 〈R2〉/〈S2〉 increase with λ. However, when the elongation ratio becomes larger, the curves of 〈R2〉/〈S2〉 become smooth and they are close to the limit of 10.50 for different compact polymers. We also investigate the changes of interior conformations in the process of tensile elongation through calculating the probabilities of three bond angles (i.e., 90°, 180°, and 270°). The average energy and Helmholtz free energy per bond are both negative and increase with elongation ratio λ. In the meantime, the elastic force per bond (f ) also increases with elongation ratio λ, and the energy contribution to the elastic force (fU) increases first and then drops, and there exists the maximum of fU in the region of λ=1.40–1.80 for different sequences. The entropy contribution to force (fS) is close to zero at a small elongation ratio λ and then increases with λ. Some comparisons with different sequences (including nonfolding and folding sequences) are also made.
The interface between benzenes (C6H6;C6H5Cl;2-C6H4OHCl) and amorphous solid water studied with metastable impact electron spectroscopy and ultraviolet photoelectron spectroscopy (HeI and II)
Authors: Borodin A. , Höfft O. , Kahnert U. , Kempter V. , Krischok S. , Abou-Helal M. O.
Published: March 2004

Interfaces between films of benzenes (C6H6;C6H5Cl;2-C6H4OHCl) and solid H2O on tungsten substrates were studied between 80 and 200 K with metastable impact electron spectroscopy (MIES) and ultraviolet photoelectron spectroscopy [UPS(HeI and II)]. The following cases were studied in detail: (i) Adsorption of the benzenes on solid water in order to simulate their interaction with ice particles, and (ii) deposition of water on benzene films in order to simulate the process of water precipitation. In all cases the prepared interfacial layers were annealed up to 200 K under in situ control of MIES and UPS. The different behavior of the interfaces for the three studied cases is traced back to the different mobilities of the molecules with respect to that of water. The interaction between H2O and the benzenes at the interfaces is discussed on the basis of a qualitative profile for the free energy of that component of the interface which has the larger mobility. Possible implications of the present results for atmospheric physics are briefly mentioned.
Stability and structure of LinH molecules (n=3–6): Experimental and density functional study
Authors: Wu C. H. , Jones R. O.
Published: March 2004

The molecules Li3H and Li4H have been identified in mass-spectrometric measurements over solutions of hydrogen in liquid Li, and the gaseous equilibria of the reactions: Li3H+Li=Li2H+Li2, Li3H+Li2=Li2H+Li3, Li3H+Li=LiH+Li3, Li3H+LiH=2Li2H, and Li4H+Li2=Li3H+Li3 have been measured. Density functional calculations of LinH molecules (n=3–6) provide structures, vibrational frequencies, ionization energies, and free energy functions of these molecules, and these are used to estimate the enthalpies of these reactions and the atomization energies of Li3H (119.4 kcal/mol) and Li4H (151.8 kcal/mol).
Early vigorous growth is a major factor influencing nitrogen uptake in wheat
Authors: Liao Mingtan , Fillery Ian R. P. , Palta Jairo A.
Published: March 2004

A field trial, a lysimeter system study and a nutrient solution experiment were conducted to determine the genotypic differences in nitrogen (N) uptake among wheat (Triticum aestivum L.) genotypes differing in vigour of early growth. Plant growth and N uptake of Vigour 18, a breeding line with early vigour, and the commercial cultivars Westonia, Tincurrin, Camm and Janz were compared. Shoot biomass of Vigour 18 was higher than that of the other genotypes, except for Westonia at booting when 50 kg N ha–1 was applied 3 d after wheat emergence. Vigour 18 had significantly higher efficiency of fertiliser-N uptake than the other four cultivars at tillering when 50�kg N ha–1 was applied. Fertiliser-N uptake efficiency at booting was similar in Vigour 18 and Westonia, but significantly higher than in three other commercial cultivars. Vigour 18 had higher root dry matter, root-length density and root surface area than Janz when examined in columns of soil. The greater root growth of Vigour 18 occurred across all soil layers to a depth of 0.6 m. Differences in total N uptake between Vigour 18 and Janz were apparent from tillering (Z14,22) to booting (Z19,24,49). Vigour 18 also had significantly higher shoot biomass and N uptake than Janz when grown in nutrient culture. Nitrate reductase activity (NRA) expressed on a whole-plant basis was higher for Vigour 18 than for Janz, and was related to total N uptake. However, NRA expressed on a per-unit-fresh-weight basis was not significantly different across the cultivars tested. It is concluded that vigorous early root and shoot growth in Vigour 18 was the main driving force for higher N uptake.
Control of gravitropic orientation. I. Non-vertical orientation by primary roots of maize results from decay of competence for orthogravitropic induction
Authors: LaMotte Clifford E. , Pickard Barbara G.
Published: March 2004

Plant organs may respond to gravity by vertical (orthogravitropic), oblique (plagiogravitropic) or horizontal (diagravitropic) growth. Primary roots of maize (Zea mays L.) provide a good system for studying such behaviours because they are reportedly capable of displaying all three responses. In current work using maize seedlings of the Silver Queen cultivar, stabilisation of growth at an oblique orientation was commonplace. Hypothetically, plagiogravitropism may be accomplished either by a process we call graded orthogravitropism or by hunting about a sensed non-vertical setpoint. In graded orthotropism primary bending is unidirectional and depends on facilitative stimuli that determine its extent. The hallmark of the setpoint mechanism is restorative curvature of either sign following a displacement; both diagravitropism and orthogravitropism are based on setpoints.Roots settled in a plagiogravitropic orientation were tested with various illumination and displacement protocols designed to distinguish between these two hypotheses. The tests refuted the setpoint hypothesis and supported that of graded orthotropism. No evidence of diagravitropism could be found, thus, earlier claims were likely based on inadequately controlled observations of graded orthotropism.We propose that orthotropism is graded by the sequential action of dual gravity receptors: induction of a vectorial gravitropic response requires gravitational induction of a separate facilitative response, whose decay in the absence of fresh stimuli can brake gravitropism at plagiotropic angles.
Physiological and morphological responses of grassland species toelevated atmospheric CO2 concentrations in FACE-systems andnatural CO2 springs
Authors: Marchi Susanna , Tognetti Roberto , Vaccari Francesco Primo , Lanini Mario , Kaligarič Mitja , Miglietta Francesco , Raschi Antonio
Published: March 2004

Stomatal density, leaf conductance and water relations can be affected by an increase in the concentration of atmospheric CO2, and thus affect plant productivity. However, there is uncertainty about the effects of elevated CO2 on stomatal behaviour, water relations and plant productivity, owing to the lack of long-term experiments in representative natural ecosystems. In this work, variations in stomatal density and index, leaf water relations and plant biomass of semi-natural grassland communities were analysed under field conditions by comparing plants in three different experimental set-ups (natural CO2 springs, plastic tunnels and mini-FACE systems). Natural degassing vents continuously expose the surrounding vegetation to truly long-term elevated CO2 and can complement short-term manipulative experiments. Elevated CO2 concentration effects on stomata persist in the long term, though different species growing in the same environment show species-specific responses. The general decrease in stomatal conductance after exposure to elevated CO2 was not associated with clear changes in stomatal number on leaf surfaces. The hypothesis of long-term adaptive modifications to stomatal number and distribution of plants exposed to elevated CO2 was not supported by these experiments on grassland communities. Elastic cell wall properties were affected to some extent by elevated CO2. Above-ground biomass did not vary between CO2 treatments, leaf area index did not compensate for reduced stomatal conductance, and the root system had potentially greater soil exploration capacity. Considerable between-species variation in response to elevated CO2 may provide a mechanism for changing competitive interactions among plant species.
From controlled environments to field simulations: leaf area dynamics and photosynthesis of kiwifruit vines (Actinidia deliciosa)
Authors: Greer Dennis H. , Seleznyova Alla N. , Green Steven R.
Published: March 2004

Canopy leaf area development and daily rates of carbon acquisition of kiwifruit [Actinidia deliciosa (A.�Chev.) C.F. Liang et A.R. Ferguson] vines growing in orchard conditions were modelled from mathematically-based physiological descriptions of leaf area expansion and photosynthesis of individual leaves Model drivers were temperatures and photon flux densities (PFD) measured in the orchard at 30-min intervals over the growing season. A modelling framework of shoot leaf area expansion, developed from controlled environment studies, was extended to whole vines by including canopy architectural components, such as shoot numbers, percentage budbreak and proportions of shoots in different length classes. Daily photosynthesis was modelled from rectangular hyperbolic functions determined for both sun and shade leaves and simulated from calculated light interception. Canopy leaf area, photosynthesis and PFDs within the canopy, obtained from measurements from vines grown in the orchard, were used to test the model. Close agreement occurred between the simulated and measured canopy leaf area development, and also between simulated and measured rates of photosynthesis. Total carbon acquisition over the growing season, estimated at 11 kg vine–1, compared closely with measured increments in vine biomass over the growing season. Results thus confirm the physiologically based model to be readily scalable to whole vines growing in orchard conditions.
Over-expression of a high-affinity phosphate transporter in transgenic barley plants does not enhance phosphate uptake rates
Authors: Rae Anne L. , Jarmey Janine M. , Mudge Stephen R. , Smith Frank W.
Published: March 2004

Transgenic barley plants that over-express the gene encoding a phosphate transporter were generated and used to test the hypothesis that manipulation of transporters may lead to improved phosphate uptake by plant roots. Replicate T2 seedlings from a homozygous line with a single locus insertion were grown in dilute flow culture. The phosphate contents and uptake rates of these plants were compared with control transgenic and wild-type plants. When external phosphate concentration was maintained at 10 μM, all plants including the transgenic over-expressing line displayed low rates of phosphate uptake and contained high levels of phosphate in the shoot tissue. When external phosphate concentration was maintained at 2 μM, the uptake rates increased to a similar level in all plant lines. Three transgenic over-expressing lines were then grown in soil at a range of phosphate concentrations and the dry weights and total phosphorus contents of the shoots were measured and compared to a transgenic control line. The results showed that over-expression of the gene encoding a phosphate transporter did not improve the uptake of phosphate under any of the conditions tested. Transporter activity is likely to be influenced by post-transcriptional mechanisms and will require further investigation before this strategy can be applied to improving plant nutrition.
Identification and characterization of a novel tobacco mosaic virus resistance N gene homologue in Nicotiana tabacum plants
Authors: Stange Claudia , Matus José Tomás , Elorza Alvaro , Arce-Johnson Patricio
Published: March 2004

Nicotiana tabacum cv. Xanthi nn plants are susceptible to infection by most tobamoviruses (TMV). However, such plants display a partial hypersensitive resistance response (HR-like response) to TMV-Cg. The genetic mechanism of the HR-like response has yet not been determined, but it may involve a gene with a function similar to that of a resistance gene, responsible for HR in resistant plants. We have cloned a gene homologous to the resistance N gene, named NH, from Nicotiana Xanthi nn plants. The coding region of NH is 5.028 base pairs (bp) long and has 82.6% nucleotide identity with the N gene. In contrast to the N gene, the NH gene lacks intron 4 and does not have sites for alternative splicing of intron 3. Analysis of its sequence revealed that NH belongs to the TIR / NSB / LRR gene class. We were able to detect stable levels of NH-transcript in Nicotiana Xanthi nn plants from 0 to 18 h post-inoculation (hpi) with TMV-Cg. Transcript levels increased slightly at 24 hpi and dropped below basal values at 48 hpi. The NH transcript was also detected in a range of resistant Nicotiana plants (N. tabacum Xanthi NN, N. glutinosa, N. glauca and N. rustica) suggesting that NH is a homologue of the N gene, rather than an allele. We have cloned and characterised the NH gene (GenBank acc. no. bankit598573 AY535010) from nn susceptible plants and postulate that this gene might be involved in the HR-like response seen in these plants.
Partitioning of 13C-labelled photosynthate varies with growth stage andpanicle size in high-yielding rice
Authors: Mohapatra Pravat K. , Masamoto Yasuyuki , Morita Satoshi , Takanashi Junichi , Kato Tsuneo , Itani Tomio , Adu-Gyamfi Joseph J. , Shunmugasundaram Muthiah , Nguyen NguyenTran , Saneoka Hirofumi , Fujita Kounosuke
Published: March 2004

A super-high-yielding rice (Oryza sativa L.) cultivar, Takanari, and a traditional japonica rice cultivar, Nakateshinsenbon, were grown under field conditions to compare partitioning of 13C-labelled photosynthate to different plant organs during the period of reproductive development. The flag leaf and the two leaves immediately below it on the main culm were exposed individually to 13CO2 and the movement of the heavy carbon isotope to grains, hull, panicle branches and vegetative parts of plant was assessed. Also, the effect of a reduction of sink size on the partitioning of 13C to different organs was studied by removing some of the primary branches of the panicle. 13C taken up by the three leaves in the post-heading period, moved mostly to the grains and hull of the panicle. At this stage, the uppermost three leaves and the panicle consisted of a single source–sink unit. Partitioning of 13C to the rest of the vegetative structures of the plant was minimal. In the case of Nakateshinsenbon, the flag leaf supplied most of the carbon assimilates for the grains and contributions from the other two leaves were much smaller. However, in Takanari, the contribution of 13C to grains from the second leaf was equivalent to that of the flag leaf. In Takanari, removal of more than one third of the primary branches of the panicle significantly reduced partitioning from the third leaf of the culm, but partitioning from the flag leaf was not significantly changed. In contrast, branch removal treatment significantly depressed transport of carbon assimilates from the flag leaf in Nakateshinsenbon. The obligatory nature of the source–sink relationship in rice is discussed. It is concluded that in lower-yielding traditional rice, photosynthesis in the flag leaf supplies carbon assimilates to the developing grains. But in the super-yielding rice Takanari, the main source area is extended to include the two leaves below the flag leaf so as to sustain an extra large panicle. Even greater grain-filling is possible in super-yielding rice, if the source area is increased further.
The molecularisation of taxonomy
Authors: Lee Michael S. Y.
Published: March 2004

The recent proposal for a new system of biological taxonomy based primarily on DNA sequences from one or a few chosen ('standard') genes sequenced across all taxa appears inadvisable for both practical and theoretical reasons. While nucleotide sequences are more objective than traditional (e.g. morphological) data in some respects (character choice, character delineation, character state identity), in other respects both are inherently subjective (homology/alignment, divergence metrics). Sequence divergence in standard gene(s) is an extremely crude method for determining species limits; more appropriate markers (potentially directly linked to species criteria such as reproductive isolation) should be and often are used. It is thus worth persisting with the plurality of genetic, anatomical and ethological criteria currently used to hypothesise ('identify') and test species boundaries. However, once species boundaries have been thus discerned, use of sequences from standard genes to diagnose those boundaries (and place individuals with respect to those boundaries) is highly feasible, though subject to error like any single type of marker. In many cases this approach might have advantages over morphological diagnoses. However, unless an appropriate taxonomic framework constructed using all appropriate biological information is already in place, such molecular diagnoses will be premature.
Evaluation of a computer-based nutrition education tool
Authors: Kreisel Katrin
Published: March 2004

Objective:

To evaluate the efficacy and feasibility of using a computer-based teaching tool (http://www.coolfoodplanet.org) for nutrition and lifestyle education developed for primary school children.

Design:

This was a 2-week school-based intervention in third and fourth grades. The study design was multi-factorial with repeated measures of nutrition knowledge, at three points in time, of dependent samples from control and intervention groups. Control schools (n=7) used ‘traditional’ nutrition education materials and intervention schools (n=8) additionally used the computer-based educational tool. Qualitative information was collected in focus group discussions with student teachers and pupils, and by observing the nutrition lessons.

Setting/subjects:

Pupils aged 8–11 years (n=271) from participating schools in Vienna, Austria.

Results:

Nutrition knowledge increased significantly in both intervention and control schools, irrespective of the teaching tool used (P<0.001). The significant effect was maintained at 3 months' follow-up. There was no detectable difference in nutrition knowledge post intervention or at follow-up between the two study groups. In intervention schools, younger pupils (8–9 years) had better nutrition knowledge than older pupils (10–11 years) (P=0.011).

Conclusion:

This computer-based tool increases the possibilities of school-based nutrition education. If the tool's weaknesses identified during the formative evaluation are eliminated, it has the potential to make learning about nutrition more enjoyable, exciting and effective. This is of great importance considering that ‘healthy’ nutrition is not necessarily a topic that easily attracts pupils' attention and in view of the potential long-term health benefits of early and effective nutrition education.
History of the concept of ‘levels of evidence’ and their current status in relation to primary prevention through lifestyle interventions
Authors: Kroke A , Boeing H , Rossnagel K , Willich SN
Published: March 2004

Primary prevention is a major option to reduce the burden of chronic disease in populations. Because lifestyle interventions have proved to be effective, lifestyle recommendations including nutritional advice are made abundantly. However, both their credibility and their effectiveness are often considered not to be high. Therefore, scientific evidence should form the basis of recommendations and, as in clinical medicine, a rational approach should be followed for the evaluation of evidence. In this paper, the development and current concepts of ‘levels of evidence’ as they are applied in clinical medicine are outlined and their impact on evidence-based recommendations is discussed. Next, the question is raised as to how far the existing schemes are applicable to the evaluation of issues pertaining to primary prevention through lifestyle changes. Current schemes were developed mainly for clinical research questions and therefore place major emphasis on randomised controlled trials as the main and most convincing evidence in the evaluation process. These types of study are rarely available for lifestyle-related factors and might even not be feasible to obtain. Arguments are advanced to support the notion that a modification of currently existing ‘levels of evidence’ as developed for clinical research questions might be necessary. Thereby, one might be able to accommodate the specific aspects of evidence-related issues of recommendations for primary prevention through lifestyle changes, like dietary changes.
Hot Cooking Oil Burns: A 20-Year Experience
Authors: Gray Katherine , Cheng Eddie , Pegg Stuart
Published: March 2004

Hot cooking oil burns resulted in 316 admissions to the Burns Unit at The Royal Brisbane Hospital between January 1, 1981, and December 31, 2000. Notable demographics of this group were a male:female ratio 1.74:1 and that 24% of all patients were between the ages of 16 and 20. Workplace burns accounted for 6% of admissions only, but these tended to be of a larger total body surface area involvement. The mean duration of admission was 8.5 days, with 40% of patients undergoing surgical débridement and split-skin grafting. Two hundred thirty-nine patients had 5% or less TBSA burned, most commonly involving the hands, legs, feet, and the forearms. No patients in our study died. The proportion of patients undergoing débridement and grafting increased from zero patients at commencement of this study to a peak of 82.5% in 1998. We believe this reflects changing practice with earlier excision and grafting trying to achieve the best functional and cosmetic results. The lack of predisposing factors and the accidental nature of these burns mean appropriate prevention strategies are paramount to decreasing the number of burns of this type. Suggestions discussed include school-based education programs, warning labels included in product information, and mandatory fire blankets within the home.
Feeding Intolerance as a Result of Small-Intestine Intussusception in a Child With Major Burns
Authors: Kincaid M. Sean , Vavilala Monica S. , Faucher Lee , Zimmerman Jerry , Heimbach David
Published: March 2004

Feeding intolerance is common in critically ill children. We present an unusual case of jejunojejunal intussusception causing feeding intolerance in a child with major burns. An 18-month-old female was admitted to the intensive care unit after sustaining a 65% TBSA burn. Following a decompressive laparotomy for abdominal compartment syndrome, nasojejunal feeds were started immediately after surgery, which she did not tolerate. A plain abdominal radiograph revealed a collection of intraluminal air and an abdominal CT revealed a proximal jejunojejunal intussusception. The patient underwent laparotomy and an uncomplicated reduction of the small-bowel intussusception (SBI). Successful enteral feedings were commenced on hospital day 24, and the patient was discharged to home after approximately a 4.5-month hospitalization. The major learning point is that SBI can cause feeding intolerance in the child with major burns. Despite the low incidence of SBI in critically ill children, arriving at a timely diagnosis is essential because the consequences of a missed or delayed diagnosis include intestinal ischemia, necrosis, or perforation. Because SBI defies diagnosis by techniques traditionally used to diagnose intussusception involving the colon, clinical suspicion for intussusception is needed to facilitate the urgent diagnosis and correction of feeding intolerance caused by mechanical obstruction.
Cytokines and Wound Healing: The Role of Cytokine and Anticytokine Therapy in the Repair Response
Authors: Efron Philip A. , Moldawer Lyle L.
Published: March 2004

Wound healing is an integrated and complex process involving a large number of regulatory molecules, including proinflammatory cytokines and growth factors, and an orchestrated tissue response. Dysregulation in cytokine or growth factor expression dramatically alters the normal wound healing process, and blocking the inappropriate production of specific proinflammatory cytokines or supplementing the milieu with increased quantities of growth factors has demonstrated the central role played by these mediators. Both protein-based and DNA-based (gene transfer) therapies are currently under clinical development as tools to improve the healing process. Although there has been some success with these approaches in both experimental models and in patients, only through a better understanding of the complexity and diversity of the wound healing process, as well as an improved comprehension of the time-dependent and concentration-dependent responses to individual proinflammatory cytokines or growth factors, will further development in the therapeutic treatment of healing wounds be attained.
Using Behavioral Science to Improve Fire Escape Behaviors in Response to a Smoke Alarm
Authors: Thompson N. J. , Waterman M. B. , Sleet D. A.
Published: March 2004

Although the likelihood of fire-related death in homes with smoke alarms is about one-half that in homes without alarms, alarm effectiveness is limited by behavior. Only 16% of residents of homes with alarms have developed and practiced plans for escape when the alarm sounds. We reviewed literature to identify behavioral constructs that influence smoke alarm use. We then convened experts in the behavioral aspects of smoke alarms who reviewed the constructs and determined that the appropriate areas for behavioral focus were formulating, practicing, and implementing escape plans should an alarm sound. They subsequently identified important behaviors to be addressed by burn-prevention programs and incorporated the constructs into a behavioral model for use in such programs. Finally, we organized the available literature to support this model and make programmatic recommendations. Many gaps remain in behavioral research to improve fire escape planning and practice. Future research must select the target behavior, apply behavioral theories, and distinguish between initiation and maintenance of behaviors associated with planning, practicing, and implementing home fire escape plans.
Microbicidal Properties of a Silver-Containing Hydrofiber® Dressing Against a Variety of Burn Wound Pathogens
Authors: Bowler P. G. , Jones S. A. , Walker M. , Parsons D.
Published: March 2004

Partial-thickness burns are often characterized by microbial contamination and copious exudate produced during the early postburn period. Consequently, topical wound management often relies on the use of antimicrobial agents and absorbent dressings, and an AQUACEL® Hydrofiber® Dressing containing ionic silver has been designed to meet such needs. To assess the antimicrobial properties of the AQUACEL® Hydrofiber® dressing, samples were challenged with a wide variety of recognized burn wound pathogens in a simulated wound fluid model. Dressing samples were inoculated with the challenge organisms at time zero and then reinoculated on days 4 and 9 to mimic the worst-case clinical scenario. The dressing was shown to be microbicidal against aerobic and anaerobic bacteria (including antibiotic-resistant strains), yeasts, and filamentous fungi during a 14-day test period. Based on our results, the silver-containing dressing is likely to provide a barrier to infection, in addition to providing proven fluid-handling benefits of the AQUACEL® Hydrofiber® dressing, in the management of partial-thickness burns.
Role of the TAK1-NLK-STAT3 pathway in TGF-β-mediated mesoderm induction
Authors: Ohkawara Bisei , Shirakabe Kyoko , Hyodo-Miura Junko , Matsuo Ritsuko , Ueno Naoto , Matsumoto Kunihiro , Shibuya Hiroshi
Published: March 2004

Transforming growth factor (TGF)-β-activated kinase 1 (TAK1) and Nemo-like kinase (NLK) function in Xenopus, Drosophila, and Caenorhabditis elegans development. Here we report that serine phosphorylation of STAT3 induced by TAK1-NLK cascade is essential for TGF-β-mediated mesoderm induction in Xenopus embryo. Depletion of TAK1, NLK, or STAT3 blocks TGF-β-mediated mesoderm induction. Coexpression of NLK and STAT3 induces mesoderm by a mechanism that requires serine phosphorylation of STAT3. Activin activates NLK, which in turn directly phosphorylates STAT3. Moreover, depletion of either TAK1 or NLK inhibits endogenous serine phosphorylation of STAT3. These results provide the first evidence that TAK1-NLK-STAT3 cascade participates in TGF-β-mediated mesoderm induction.
Role of the processing pore of the ClpX AAA+ ATPase in the recognition and engagement of specific protein substrates
Authors: Siddiqui Samia M. , Sauer Robert T. , Baker Tania A.
Published: March 2004

ClpX binds substrates bearing specific classes of peptide signals, denatures these proteins, and translocates them through a central pore into ClpP for degradation. ClpX with the V154F pore mutation is severely defective in binding substrates bearing C-motif 1 degradation signals and is also impaired in a subsequent step of substrate engagement. In contrast, this mutant efficiently processes substrates with other classes of recognition signals both in vitro and in vivo. These results demonstrate that the ClpX pore functions in the recognition and catalytic engagement of specific substrates, and that ClpX recognizes different substrate classes in at least two distinct fashions.
mTOR-dependent activation of the transcription factor TIF-IA links rRNA synthesis to nutrient availability
Authors: Mayer Christine , Zhao Jian , Yuan Xuejun , Grummt Ingrid
Published: March 2004

In cycling cells, transcription of ribosomal RNA genes by RNA polymerase I (Pol I) is tightly coordinated with cell growth. Here, we show that the mammalian target of rapamycin (mTOR) regulates Pol I transcription by modulating the activity of TIF-IA, a regulatory factor that senses nutrient and growth-factor availability. Inhibition of mTOR signaling by rapamycin inactivates TIF-IA and impairs transcription-initiation complex formation. Moreover, rapamycin treatment leads to translocation of TIF-IA into the cytoplasm. Rapamycin-mediated inactivation of TIF-IA is caused by hypophosphorylation of Ser 44 (S44) and hyperphosphorylation of Ser 199 (S199). Phosphorylation at these sites affects TIF-IA activity in opposite ways, for example, phosphorylation of S44 activates and S199 inactivates TIF-IA. The results identify a new target for mTOR-signaling pathways and elucidate the molecular mechanism underlying mTOR-dependent regulation of rRNA synthesis.
Pax5 inducesV-to-DJrearrangements and locus contraction of theimmunoglobulin heavy-chaingene
Authors: Fuxa Martin , Skok Jane , Souabni Abdallah , Salvagiotto Giorgia , Roldan Esther , Busslinger Meinrad
Published: March 2004

The subnuclear location and chromatin state of theimmunoglobulin heavy-chain(IgH) locus have been implicated in the control ofV(D)Jrecombination.VH-to-DJHrearrangement of distal, but not proximalVHgenes, furthermore, depends on the B-lineage commitment factor Pax5 (BSAP). Here we demonstrate that ectopicPax5expression from theIkarospromoter induces proximal rather than distalVH–DJHrearrangements inIkPax5/+thymocytes, thus recapitulating the loss-of-function phenotype ofPax5–/–pro-B cells. The phenotypic similarities of both cell types include (1) chromatin accessibility of distalVHgenes in the absence ofVH–DJHrearrangements, (2) expression of the B-cell-specific regulator EBF, (3) central location ofIgHalleles within the nucleus, and (4) physical separation of distalVHgenes from proximal segments in an extendedIgHlocus. Reconstitution ofPax5expression inPax5–/–pro-B cells induced large-scale contraction and distalVH–DJHrearrangements of theIgHlocus. Hence,VH–DJHrecombination is regulated in two steps during early B-lymphopoiesis. TheIgHlocus is first repositioned from its default location at the nuclear periphery toward the center of the nucleus, which facilitates proximalVH–DJHrecombination. Pax5 subsequently activates locus contraction and distalVH–DJHrearrangements in collaboration with an unknown factor that is present in pro-B cells, but absent in thymocytes.
Type-A Arabidopsis Response Regulators Are Partially Redundant Negative Regulators of Cytokinin Signaling[W]
Authors: To Jennifer P.C. , Haberer Georg , Ferreira Fernando J. , Deruère Jean , Mason Michael G. , Schaller G. Eric , Alonso Jose M. , Ecker Joseph R. , Kieber Joseph J.
Published: March 2004

Type-A Arabidopsis (Arabidopsis thaliana) response regulators (ARRs) are a family of 10 genes that are rapidly induced by cytokinin and are highly similar to bacterial two-component response regulators. We have isolated T-DNA insertions in six of the type-A ARRs and constructed multiple insertional mutants, including the arr3,4,5,6,8,9 hextuple mutant. Single arr mutants were indistinguishable from the wild type in various cytokinin assays; double and higher order arr mutants showed progressively increasing sensitivity to cytokinin, indicating functional overlap among type-A ARRs and that these genes act as negative regulators of cytokinin responses. The induction of cytokinin primary response genes was amplified in arr mutants, indicating that the primary response to cytokinin is affected. Spatial patterns of ARR gene expression were consistent with partially redundant function of these genes in cytokinin signaling. The arr mutants show altered red light sensitivity, suggesting a general involvement of type-A ARRs in light signal transduction. Further, morphological phenotypes of some arr mutants suggest complex regulatory interactions and gene-specific functions among family members.
Microarray Expression Analyses of Arabidopsis Guard Cells and Isolation of a Recessive Abscisic Acid Hypersensitive Protein Phosphatase 2C Mutant[W]
Authors: Leonhardt Nathalie , Kwak June M. , Robert Nadia , Waner David , Leonhardt Guillaume , Schroeder Julian I.
Published: March 2004

Oligomer-based DNA Affymetrix GeneChips representing about one-third of Arabidopsis (Arabidopsis thaliana) genes were used to profile global gene expression in a single cell type, guard cells, identifying 1309 guard cell–expressed genes. Highly pure preparations of guard cells and mesophyll cells were isolated in the presence of transcription inhibitors that prevented induction of stress-inducible genes during cell isolation procedures. Guard cell expression profiles were compared with those of mesophyll cells, resulting in identification of 64 transcripts expressed preferentially in guard cells. Many large gene families and gene duplications are known to exist in the Arabidopsis genome, giving rise to redundancies that greatly hamper conventional genetic and functional genomic analyses. The presented genomic scale analysis identifies redundant expression of specific isoforms belonging to large gene families at the single cell level, which provides a powerful tool for functional genomic characterization of the many signaling pathways that function in guard cells. Reverse transcription–PCR of 29 genes confirmed the reliability of GeneChip results. Statistical analyses of promoter regions of abscisic acid (ABA)–regulated genes reveal an overrepresented ABA responsive motif, which is the known ABA response element. Interestingly, expression profiling reveals ABA modulation of many known guard cell ABA signaling components at the transcript level. We further identified a highly ABA-induced protein phosphatase 2C transcript, AtP2C-HA, in guard cells. A T-DNA disruption mutation in AtP2C-HA confers ABA-hypersensitive regulation of stomatal closing and seed germination. The presented data provide a basis for cell type–specific genomic scale analyses of gene function.
Plant Respiratory Burst Oxidase Homologs Impinge on Wound Responsiveness and Development inLycopersicon esculentum [W]
Authors: Sagi Moshe , Davydov Olga , Orazova Saltanat , Yesbergenova Zhazira , Ophir Ron , Stratmann Johannes W. , Fluhr Robert
Published: March 2004

Plant respiratory burst oxidase homologs (Rboh) are homologs of the human neutrophil pathogen-related gp91phox. Antisense technology was employed to ascertain the biological function of Lycopersicon esculentum (tomato) Rboh. Lines with diminished Rboh activity showed a reduced level of reactive oxygen species (ROS) in the leaf, implying a role for Rboh in establishing the cellular redox milieu. Surprisingly, the antisense plants acquired a highly branched phenotype, switched from indeterminate to determinate growth habit, and had fasciated reproductive organs. Wound-induced systemic expression of proteinase inhibitor II was compromised in the antisense lines, indicating that ROS intermediates supplied by Rboh are required for this wound response. Extending these observations by transcriptome analysis revealed ectopic leaf expression of homeotic MADS box genes that are normally expressed only in reproductive organs. In addition, both Rboh-dependent and -independent wound-induced gene induction was detected as well as transcript changes related to redox maintenance. The results provide novel insights into how the steady state cellular level of ROS is controlled and portrays the role of Rboh as a signal transducer of stress and developmental responses.
Ferrofluid lubrication in step bearing with two steps
Authors: Shah Rajesh C.
Published: March 2004

A study of step bearing lubricated with a ferrofluid was made in this paper. Shah and Bhat considered the term μ0M(∂H/∂x) of ferrofluid as lubricant. The present paper discusses the problem with the modified term as μ0M (∂H/∂x)+(16πμ0r3χM)/(9(l+2)3)(∂H/∂x) of ferrofluid which incorporates more properties of ferrofluids. Expressions for pressure under the two steps and load carrying capacity were obtained. It was observed that the use of ferrofluid increases the load capacity of the bearing. Also load capacity become more when the length of the first step was taken less.
Friction damage of aluminium alloys
Authors: Elleuch Khaled , Mezlini Salah , Fouvry Siegfried , Kapsa Philippe
Published: March 2004

Damage of aluminium alloy under contact loading is detected in different cases independent of contact configuration and operating conditions. An investigation of two industrial cases is proposed to describe how it is possible to study the material degradation under friction. The experimental simulation of aluminium damage in laboratory conditions is carried out. Two contact configurations are studied in order to reproduce the industrial damage of aluminium alloys. Varying experimental conditions relative to a specific contact body for each test have demonstrated a realistic correlation between damage, test configuration and material properties. Independent of the tribological system, plastic deformation seems to be the major parameter controlling the wear of aluminium alloy under friction in the studied cases.
Identification of HLA‐B*56 variant (B*560502) in the Korean population
Authors: Pyo C‐W. , Hur S‐S. , Kim D‐W. , Kim C‐C. , Han H. , Kim T‐G.
Published: March 2004

Abstract:  We report here a new HLA‐B*56 allele, B*560502, identified by sequencing‐based typing in the Korean population. HLA‐B*560502 differs from B*560501 by a single nucleotide at position 141 in exon 2 (T(r)C). This single nucleotide substitution may not result in an amino acid difference in the α1 domain at residue 23. The putative haplotype involving B*560502 may be A*24‐DRB1*1201‐DQA1*0503‐DQB1*0304‐DPB1*0202.