bluuebunny/crossref_metadata_2025_split huggingface dataset:
Atomic Force Microscopy Applied to the Study of Whatman Paper Surface Deteriorated by a Cellulolytic Filamentous Fungus
Authors: Piantanida G. , Pinzari F. , Montanari M. , Bicchieri M. , Coluzza C. 
Published: April 2006

AbstractIn this study AFM technique has been used to observe the degradation of cellulose fibres in paper samples used as substrata for the growth of a filamentous fungus known to be responsible for damage to art works made from or supported on paper. Images obtained from the analysis of artificially deteriorated samples have been used for comparison with topographies obtained by AFM from naturally affected samples. As “control” images, AFM topographies of samples obtained from the same paper quality utilised as substrata for fungal inoculum were considered. The samples that were artificially deteriorated and those naturally affected by biological agents showed, at the molecular level, distinct surface differences when compared with control images. The biodegradation of cellulose fibres that appeared in AFM images can be attributed to the activity of both cellulolytic enzymes and acidic compounds produced by the fungal cells. Further studies using the AFM technique could reveal interesting aspects of paper biodeterioration caused by different microrganisms and might allow for a better description of the different stages of fungal attacks on cellulose fibres.
Miniaturized microstrip array for the UHF‐band RFID reader
Authors: Wu Ze‐hai , Lai Sheng‐li 
Published: April 2006

AbstractIn this paper, a new array antenna composed of Koch fractal microstrip patches for the UHF‐band RFID reader is proposed. The investigation shows that the coupling factor of two fractal patches in the E‐plane is much larger than that in the H‐plane, and the coefficients are smaller than that of the rectangular patch. The characteristics of the Koch array antenna have been demonstrated by experiment results: when the patch iteration factor is 0.25, the 2 × 2 fractal is 22.77% smaller than the rectangular array, and antenna gain at 915 MHz is 9.9 dB, yielding a 7‐m identification‐read range when incorporated with the RFID modules. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1299–1301, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21617
Electromagnetic bandgap structures as artificial magnetic conductor surfaces sidewalls in parallel plate slot antennas
Authors: Fernández J. M. , Sierra‐Castañer M. 
Published: April 2006

AbstractMetamaterial structures have unique properties in controlling the propagation of electromagnetic waves. In this work we analyze the effect of a metamaterial denominated EBG structures acting as if they had artificial magnetic conductor (AMC) properties to enhance the main radiation characteristics of parallel‐plate slot antennas. The results using these structures in comparison with conventional perfect electric conductor (PEC) sidewalls in a planar slot antenna are presented as an example of application. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1441–1446, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21633
Planar compact elliptic‐function low‐pass filter using high‐permittivity ceramics substrate
Authors: Chen Yuan‐Bin , Huang Cheng‐Liang , Lo Ching‐Wen 
Published: April 2006

AbstractA component elliptic‐function low‐pass filter using microstrip stepped‐impedance hairpin resonators and their equivalent‐circuit models is developed. The prototype filters are synthesized from the equivalent‐circuit model using available element value tables. To optimize the performance of the filters, electro‐magnetic simulation is used to tune the dimensions of the prototype filters. The filter using multiple cascaded hairpin resonators provides a very sharp cutoff‐frequency response with low insertion loss. The full‐wave simulator IE3D is used to design the elliptic‐function low‐pass filter. The response of the fabricated filter using Al2O3 (εr = 9.7, Q × f = 350,000 GHz) and La(Mg1/2Ti1/2)O3 (εr = 28.6 Q × f = 60,000 GHz). © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1393–1398, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21637
A dual‐layered wideband microstrip reflectarray antenna with variable polarization
Authors: Wu Zhi‐Hang , Zhang Wen‐Xun , Liu Zhen‐Guo , Shen Wei 
Published: April 2006

AbstractThis paper presents a new kind of microstrip reflectarray antenna those polarization could be reconfigurable among all polarization states instead of some fixed states for dual‐ or multipolarized antenna. The mechanism for polarized variability is so simple that only mechanical rotation is needed. The complete theoretical analysis is given as well as a specific design sample to verify this method. At designed frequency of 10 GHz and in case of circularly polarized (CP) radiation, experimental results in agreement with simulated ones exhibit −26‐dB cross‐polar level (CPL), −13‐dB side‐lobe level, 13.5° half‐power beamwidth, and 17.3‐dBi gain corresponding to about 40% aperture efficiency. It also possesses 8% bandwidth from 9.5 to 10.3 GHz for CPL less than −15 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1429–1432, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21640
A millimeter‐wave slow‐wave bandpass filter using compact microstrip stepped‐impedance hairpin resonator with inter‐digital capacitor on GaAs substrate
Authors: Cho Ju‐Hyun , Yun Tae‐Soon , Lee Myeong‐Gil , Baek Tae‐Jong , Shin Dong‐Hoon , Lee Jong‐Chul 
Published: April 2006

AbstractIn this paper, a new microstrip stepped‐impedance hairpin resonator with interdigital capacitor (IDC) slow‐wave band‐pass filter (BPF) using dielectric supported air‐gapped microstrip line (DAML) of surface micromachining on GaAs substrate is proposed. Unlike conventional slow‐wave filters, the proposed bandpass filters are designed to produce a narrow passband at the fundamental mode of the resonators with small size and a sharp skirt characteristic. The proposed slow‐wave band‐pass filter with IDC is designed to produce a passband of 7.7% at the fundamental frequency of 56 GHz. It shows insertion loss of 3.37 dB, return loss of better than 15 dB, and a stopband characteristic greater than 31 dB within 37.03–45.51 GHz. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1244–1247, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21667
Analysis of 1D PBG structure using the wavelet‐Galerkin time‐domain method
Authors: Dai Shao‐yu , Wu Zhen‐sen 
Published: April 2006

AbstractIn this paper, an accelerated wavelet‐Galerkin time‐domain (WGTD) scheme for electromagnetic scattering is presented, and a numerical interface is applied to overcome the complexity of connection and absorption boundaries. The obtained reflection coefficients of photonic bandgap (PBG) show that the WGTD scheme can increase cell size without sacrificing solution accuracy and thus improve efficiency. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1258–1261, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21670
The coupling of wind and internal waves: modulation and friction mechanisms
Authors: Kudryavtsev V. N. 
Published: April 2006

The interaction between internal waves (IW) and wind waves (WW) is studied. Three types of interaction are considered: spontaneous IW generation by a random field of WWs, and two feedback mechanisms - modulation and friction.The latter mechanism has not been studied before. Its influence on the IW-WW coupling is of primary importance. The modulation and friction mechanisms result in exponential attenuation of the IWs. Attenuation of IWs propagating against wind is the strongest. The IW attenuation has a dimensionless decrement of order 10-3, whereas for storm winds it attains the value of 10-2. Joint action of the spontaneous generation of IWs and their attenuation due to feedback mechanisms permits a stationary ‘wind-IW’ spectrum to exist. For strong winds the ‘wind-IW’ energy is of order 105erg cm-2. The effect of IWs on currents in the ocean's upper layer is considered. Momentum and energy lost by IWs due to their interaction with WWs generates inertial oscillations. Under the attenuation of intensive IWs, the amplitude of inertial oscillations may be compared with the background Ekman current.
On vortex air motions above an axisymmetric source of mass, momentum and heat
Authors: Berezin Y. A. , Hutter K. 
Published: April 2006

We study axisymmetric plume dispersion from a steady source of mass, momentum and/or heat that is subjected to either a time-dependent large-scale external vortex or small-scale turbulent axisymmetric helicity. On the basis of the turbulent boundary layer and Boussinesq assumptions and by assuming similarity profiles with Gaussian distribution in the radial direction the balance equations of mass, momentum, and energy reduce to a system of nonlinear differential equations for amplitude functions of axial velocity, pressure and density differences as well as azimuthal velocity. The system of equations is closed with Taylor's entrainment assumption.The plume radius and the typical radius of the large-scale external vortex are also determined. For a simple density structure of the ambient atmosphere (i.e. adiabatic conditions) analytical results can be obtained, but for more complicated cases, i.e. a layered polytropic atmosphere, the governing equations are examined numerically; computations are reasonably simple and efficient.
The motion of a rising disk in a rotating axially bounded fluid for large Taylor number
Authors: Ungarish Marius , Vedensky Dmitry 
Published: April 2006

The motion of a disk rising steadily along the axis in a rotating fluid between two infinite plates is considered. In the limit of zero Rossby number and with the disk in the middle position, the boundary value problem based on the linear, viscous equations of motion is reduced to a system of dual-integral equations which renders ‘exact’ solutions for arbitrary values of the Taylor number, Ta, and disk-to-wall distance, H (scaled by the radius of the disk). The investigation is focused on the drag and on the flow field when Ta is large (but finite) for various H. Comparisons with previous asymptotic results for ‘short’ and ‘long’ containers, and with the preceding unbounded-configuration ‘exact’ solution, provide both confirmation and novel insights.In particular, it is shown that the ‘free’ Taylor column on the particle appears for H > 0.08 Ta and attains its fully developed features when H > 0.25 Ta (approximately). The present drag calculations improve the compatibility of the linear theory with Maxworthy's (1968) experiments in short containers, but for the long container the claimed discrepancy with experiments remains unexplained.
Osmotic adjustment to water stress in pearl millet (Pennisetum americanum[L.] Leeke) under field conditions
Authors: HENSON I. E. , MAHALAKSHMI V. , BIDINGER F. R. , ALAGARSWAMY G. 
Published: April 2006

Abstract.Osmotic adjustment, a mechanism whereby plants maintain positive turgor despite low water potential (ψ), was investigated in pearl millet (Pennisetum americanum[L.] Leeke) in three types of field experiment at Hyderabad, India:Osmotic adjustment during the growing season was evaluated by comparing solute potential (ψs) of leaves taken at midday from irrigated and droughted plots and allowed to rehydrate in the laboratory. The degree of seasonal adjustment was also estimated by comparing observed values of ψsin the field with those expected if ψsdecreased solely in proportion to water loss. Both types of assessment indicated the maximum seasonal adjustment to be about 0.2 MPa. The cultivars BJ 104 and Serere 39 differed in their capacity to adjust osmotically over the season; Serere 39 was least able to osmoregulate.Measurements of diurnal variations in ψ and ψsinBJ104 revealed osmotic adjustment during the afternoon hours. At a given value of ψ, turgor (ψp) was about 0.1 MPa higher in irrigated, and over 0.2 MPa higher in droughted plants, in the afternoon, than in the morning.Osmotic adjustment of different leaves within the canopy was investigated. Upper leaves had lower ψ than basal leaves. Differences in ψ were matched by gradients in ψs, so that turgor was similar for all leaf layers.
Mathematical treatment of water movement in plant cells and tissue: a review
Authors: MOLZ FRED J. , FERRIER JACK M. 
Published: April 2006

Abstract. Over the past three decades, many contributions have been made to the development of a mathematical basis for describing water transport in plant cells and tissue. This review paper attempts to summarize the more significant contributions and to outline the concepts upon which the various mathematical analyses are founded.The paper itself is divided into three major sections. Section I deals with the quantitative water relations of single plant cells. Basic equations are developed which describe the water statics and water dynamics of such cells. Included is a discussion of the theory and methods for measuring the various parameters (permeabilities, cell wall elastic moduli, etc.) which enter into the development. The section closes with a presentation of circuit analog models for single plant cells.Section II is devoted to a review and development of the water relations of plant tissues which contain numerous cells in series. Following a historical overview, various existing models are derived and physical tissue properties which enter the derivation are identified. The concept of ‘local equilibrium’ is discussed and circuit analog models for single cells are generalized and applied to several cells in series.The final section contains two example applications of water transport theory as it applies to plant tissue. One application involves radial water movement in a soybean hypocotyl while the other deals with water transport in a growing root tip. A summary at the end of the section is largely devoted to a discussion of the limitations of mathematical models dial are presently available.
Epidermal transpiration and stomatal responses to humidity: Some hypotheses explored
Authors: SHERIFF D. W. 
Published: April 2006

Abstract Stomatal responses to humidity as affected by both evaporation from the epidermis and the hydraulic conductance of the transpiration stream to evaporation sites on the epidermis are discussed.Recent estimates of evaporation from the inner walls of the epidermis are too high because the cell wall surfaces were assumed completely wet, and leaves have usually been considered isothermal.It is suggested that a fall in humidity increases evaporation from the epidermis, and that stomata respond to the consequent fall in water potential. Cuticular transiration is inversely related to stomatal conductance. Thus, evaporation from the epidermis is dependent on the stomatal, boundary layer, and cuticular conductances, and on evaporation from the inner walls of the epidermis. Stomatal responses to humidity will change as the boundary layer conductance changes.The conductance of the transpiration stream is a determinant of the water potential of the epidermis. Water potentials of adjacent cells will be more similar if flow is symplastic than if it is apoplastic. It is concluded that flow in living tissues is primarily symplastic over long distances, but over shorter distances it is increasingly apoplastic, and that stomatal responses to humidity are mediated by the water potential of the whole epidermis.
Source—sink characteristics of carbon transport in Chara hispida
Authors: ANDREWS M. , BOX R. , FYSON A. , RAVEN J. A. 
Published: April 2006

Abstract Rates of uptake of 14C‐labelled inorganic carbon were measured for whole Chara hispida plants, detached parts of the shoot and isolated (split‐chamber technique) apices, lateral branchlets and rhizoid—node complexes.The rates of inorganic carbon uptake by the rhizoid—node complex expressed per gram fresh weight whole plant were three to four orders of magnitude less than the uptake for the whole plant. Up to 70% of the carbon taken up by the rhizoid—node complex was translocated to the shoot. After 12 h exposure to 14C‐labelled inorganic carbon the concentration of 14C was greater in apices than in uppermost or central internodal cells and in all lateral branchlets, regardless of whether label was supplied to the whole plant or isolated rhizoid—node complexes. Measurement of inorganic carbon uptake by detached internodal cells and detached and isolated apices and lateral branchlets showed that lateral branchlets had the greatest rates of inorganic carbon uptake. During 12 h exposure to 14C, isolated lateral branchlets translocated to the attached shoot 55% of the labelled carbon taken up; for isolated apices this value was only 13%.It is concluded that it is highly unlikely that the rhizoid of Chara hispida could acquire a significant fraction of the whole plant requirement for inorganic carbon and that apices are sink regions for photosynthate while lateral branchlets are source regions.
Isolation of Capsicum annuum leaf nitrate reductase and characterization of the effect of adenine nucleotides and NADH on its activity
Authors: WALLACE W. , STEER B. T. 
Published: April 2006

Abstract. In the preliminary purification of Capsicum leaf nitrate reductase (EC 1.6.6.1), treatment of the crude extract on Sephadex G‐25 was necessary to prevent a gelling of the extract and sedimentation of the enzyme. Its Km values for NADH and nitrate were estimated to be 9.3 and 105mmol m−3 ADP and ATP gave hyperbolic competitive inhibition, with respect to NADH, while the inhibition by AMP was linear competitive. Ki values calculated were: ADP and ATP approximately lmol m−3 and AMP 2.3 mol m−3. Inhibition by ADP was not altered by reduced glutathione.The Capsicum nitrate reduclase was very susceptible to inhibition by NADH (in the absence of nitrate) and an in vivo assay showed that the activity of the enzyme was limited by the supply of nitrate. NADH and adenine nucleotide levels measured in the Capsicum leaf were used to estimate inhibition of nitrate reductase and a prediction was made of the nitrate reductase activity at different times in the photoperiod. This was shown to follow the same trend as the measured in vivo activity of the enzyme. Changes in adenine nucleotide levels had little effect on nitrate reductase activity.
Scanning electron microscopic aspects of short tuberized roots, with special reference to cell rhizodermis evolution under drought and rehydration
Authors: VARTANIAN N. , WERTHEIMER D. S. , COUDERC H. 
Published: April 2006

Abstract. Different morphological aspects of short tuberized roots initiated during drought stress in mesophytic species, such as Sinapis alba L., were studied with the scanning electron microscopy technique of cryofixation. Specially adapted for direct and immediate observation of fresh living roots, this method has given precise information about rhizodermal organization and evolution during drought and rehydration.The main difference from a normal lateral root grown in a well‐watered soil appears in the basal enlarged zone of the short root where all the cells show the same round and turgid aspect. In the medium zone of the short root, rhizodermis differentiation into alternating rows of short (trichoblasts) and long (atrichoblasts) cells, which characterizes the typical Sinapis root, remains clearly discernible, though not so regular as in normal lateral roots.The turgid state of rhizodermal cells all over the short tuberized root grown in a drying soil suggests an effective regulatory mechanism for water deficit avoidance.During the first hours of rehydration, immediate absorption of water is noticeable through the rapid swelling of some long cells which appear to protrude considerably among other rhizodermal cells. However, these protrusions will not give rise to hairs, as further observations of short roots after growth has resumed show very distinctly that progressive hair formation occurs in the medium zone of the root, and that their emergence originates from trichoblasts only.These observations may indicate that atrichoblasts, on account of their highly vacuolated condition, are the first cells to absorb water and that they may even be stimulated, in some environmental conditions, to initiate hair formation, although they are not so well adapted to do so as the short cells in this species.
Control of plant growth by nitrogen: differences between cereals and broadleaf species
Authors: RADIN JOHN W. 
Published: April 2006

Abstract. In four dicotyledonous species low levels of N strongly inhibited leaf expansion during the day but had little or no effect at night. In contrast, daytime and night‐time expansion were equally affected in four cereal species. The results support the general concept that in dicotyledons, N controls leaf expansion through its effects on hydraulic conductivity. In such N‐limited plants, water deficits generated by transpiration may inhibit daytime cell expansion. In cereals, cell expansion and transpiration occur in separate zones of the leaf and are apparently unrelated.Growth analysis showed that low levels of N inhibited leaf area growth more strongly in dicotyledons than in cereals, but had similar effects on net assimilation rates of plants in the two groups. As a result, dry matter production was more efficient in cereals than in dicotyledons when N was limiting.
Photogeneration of a bioelectric field by red and far‐red irradiation in soybean hypocotyls
Authors: TANADA TAKLJMA 
Published: April 2006

Abstract.Changes in the bioelectric field potential at the apical end of dark‐grown soybean (Glycine max)hypocotyls after exposure to several wavelengths of light have been monitored with an electrometer. A small dose of 660 nm radiation brings about a rapid positive rise in the potential. A following small dose at 760 nm prevents the increase, suggesting a phytochrome action. Pre‐irradiation with 660 nm enables a subsequent larger dose of 760 nm, which by itself is without effect, to elicit a delayed rise in the potential.A large dose at 710 nm induces a delayed increase in the field potential. The increase is prevented by a following dose at 550 nm, but not at 660 nm.
Germination and seedling growth under anaerobic conditions in Echinochloa crus‐galli (barnyard grass)*
Authors: KENNEDY ROBERT A. , BARRETT SPENCER C. H. , ZEE DELMAR VANDER , RUMPHO MARY E. 
Published: April 2006

Abstract Although rice has long been recognized to be uniquely adapted for growth in low oxygen environments of flooded rice fields, rice weeds of the Echinochloa crus‐galli complex appear to be at least as well specialized for germination and growth under such unusual biological conditions.Seeds of two varieties of E. crus‐galli germinate and grow for prolonged periods in a totally oxygen‐free environment. E. crus‐galli germinates as well as rice (Oryza sativa) under a total nitrogen atmosphere and produces as large a seedling in spite of its much smaller seed size. Like rice, the seedlings of E. crus‐galli are unpigmented, the primary leaves do not emerge from the coleoptile and no root growth occurs without oxygen. Of particular interest is the ultrastructure of mitochondria from anaerobically‐grown seedlings. Mitochondrial profiles from the primary leaf of seedlings grown continuously in nitrogen are very similar to those grown aerobically. The size and shape of the mitochondria are similar and the cristae are numerous and normal in appearance. This is in sharp contrast to previous studies of other species which have reported that mitochondria were vesiculate and tended to lose their normal fine‐structure after similar periods without oxygen.Finally, based on ultrastructure and 14C labeling studies, anaerobically‐grown seedlings are highly active metabolically, which may explain, at least for E. crus‐galli var. oryzicola, its ability to germinate and emerge from flooded rice fields.