bluuebunny/crossref_metadata_2025_split huggingface dataset:
The human ductus venosus between 13 and 17 weeks of gestation: histological and morphometric studies
Authors: Mavrides E. , Moscoso G. , Carvalho J. S. , Campbell S. , Thilaganathan B. 
Published: August 2010

AbstractBackgroundDoppler studies of the ductus venosus are increasingly being integrated in the assessment of fetal well‐being. Establishing the precise morphology and structure of the ductus venosus would provide a better understanding of Doppler findings during fetal adaptation. There is conflicting evidence from previous studies about the structure of the ductus venosus, especially with regard to the presence of a sphincter at the ductus venosus inlet. The aim of this study was to examine the morphology and histological structure of the ductus venosus wall and surrounding tissues at 13–17 weeks' gestation.DesignThis was a prospective study on 28 fetuses obtained from medical termination of pregnancies between 13 and 17 weeks' gestation. Scanning electron microscopy and histological and immunohistochemical studies were carried out on ductus venosus sections obtained from different spatial planes.ResultsThe inlet of the ductus venosus contained a shelf which was rich in elastin, but devoid of any evidence of a smooth muscle sphincter. The isthmus of the ductus venosus above the inlet was narrowed, giving the lumen of the vessel an hourglass appearance. The endothelial surface of the ductus venosus, above the level of the inlet, showed longitudinal corrugations along its entire length. Longitudinally arranged elastin fibers were also seen along the length of the ductus venosus. A single layer of longitudinally arranged smooth muscle cells was present along the entire length of the ductus venosus, with occasional individual nerve cells visible in this layer.ConclusionsThe presence of an elastin‐rich shelf and a narrow ductus venosus inlet orifice may act to accelerate flow from the portal sinus into a high‐velocity system in the ductus venosus. The abundant elastin fibers in the adventitia of the ductus venosus may help antegrade wave propagation by elastic recoil. This study clearly demonstrates the lack of an anatomical smooth muscle sphincter at the ductus venosus inlet. However, the combination of endothelial corrugations and innervated smooth muscle support the hypothesis that the ductus venosus is an actively regulated vessel with the capacity to rapidly change diameter along its entire length in response to certain stimuli. Copyright © 2002 ISUOG
Spiritual Change in Drug Treatment: Utility of the Christian Inventory of Spirituality
Authors: Windsor Liliane Cambraia , Shorkey Clay 
Published: August 2010

The current study used data from reliability testing of the Christian Inventory of Spirituality (CIS) to ( 1 ) assess the utility of CIS in detecting differences in level of spirituality in residents of residential Christian faith-based substance abuse programs (RCFBSAPs); ( 2 ) test the hypothesis that residents who have been in the program for longer periods of time will have significantly higher levels of spirituality after controlling for relevant demographic characteristics; and ( 3 ) test the hypothesis that residents of programs that only use unlicensed staff and place higher importance on spirituality will have significantly higher levels of spirituality. A purposive sample of the cross-sectional data from the reliability testing of the CIS was used ( n = 253). Analysis supported the hypothesis. Demographic characteristics were not associated with level of spirituality. The CIS proved to be useful in discriminating levels of spirituality. Further research is needed to examine spiritual change using randomized pre-post test designs.
The influence of hydrothermal temperature on SnO
2 nanorod formation
Authors: Khuc Quang Trung , Hien Vu Xuan , Vuong Dang Duc , Chien Nguyen Duc 
Published: August 2010

Abstract

SnO
2 nanorods were successfully prepared by a hydrothermal method using tin chloride, liquid ammonia, sodium hydroxide and cetyltrimethyl ammonium bromide (CTAB) as starting materials. Structural properties and surface morphologies of the SnO
2 nanorods were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the diameter of the nanorods is in the range of 100–300 nm with a length of several micrometers. The hydrothermal treatment temperature was found to play an important role in determining the morphology and diameter of the SnO
2 nanorods. Possible growth mechanisms of SnO
2 nanorods were proposed.
Relative addition rate and external concentration; Driving variables used in plant nutrition research
Authors: INGESTAD TORSTEN 
Published: August 2010

Abstract An increasing literature accounting for various types of experiments indicates that far lower external nutrient concentrations are required by plants than is usually thought to be the case. It is concluded that the ion uptake capacity of the roots, as described by the carrier concept, is high compared to that required for maintenance of the internal concentration. Serious errors in experimental conclusions are associated with insufficient and constant nutrient addition rates. The main errors are caused by non‐steady states of the plants both with regard to the internal nutrient concentrations and the relative growth rate.A dynamic concept has been proposed for direct use as the treatment variable within the range of sub‐optimum nutrition. The nutritional factor is expressed as a flow, the relative nutrient addition rate in laboratory studies and the nutrient flux density in the field. The experimental use of the relative addition rate has led to steady‐state nutrient status and relative growth rate and the interpretation of plant responses which differ fundamentally from accepted views. Thus, for instance, deficiency symptoms disappear, as in natural conditions, when the internal nitrogen concentration is stable, independent of level. The nutrition/growth relationships are very different from those observed when external concentration is varied. The regression line of relative growth rate on relative addition rate passes near to the origin at an angle close to 45 to the axes, which implies that the obtained relative growth rate approximates closely the treatment variable. A striking example of observed differences is the positive effect on nitrogen fixation exerted by high relative nitrogen addition rates compared to the well‐known negative effect of increasing external nitrogen concentration.The application of fertilizer on the basis of the nutrient flux density concept provides the possibility of supplying fertilizers corresponding to the consumption potential of the vegetation and to the natural flux density resulting from mineralization in the soil. Nitrogen utilization is high under such conditions and the resulting feedback of nutrition on the mineralization rate suggests that there will be a long‐term increase in fertility.
Continuity of Midwifery Care in England: A New Professional Project?
Authors: Sandall Jane 
Published: August 2010

Over the last decade, an increasing amount of research has examined the relationship between gender and professionalization using female professional projects to illustrate how the generic notion of a profession has been a gendered one.This paper develops Witz’s (1990) theory of professional strategies in female‐dominated occupations particularly regarding midwives in Britain in the twentieth century and suggests that an important dimension that also needs to be critically examined in midwifery history is the interaction of gender and social class within midwifery. Furthermore it documents the traditional emphasis in midwifery on the single women’s career path. This historical analysis has resonance today as midwifery in Britain is undergoing a renaissance. The role of the midwife and the current organization of the maternity services are being reviewed with the intention of providing increased choice and control over the reproductive process for women and increased continuity of care with a midwife. These changes are viewed as midwives’ new professional project and the implications for midwives and women discussed.The aim of this paper is to explore the explanatory power of these approaches to current developments in maternity care and by drawing historical parallels, consider the impact that this professionalizing strategy may have for those who are excluded from this process of ‘dual closure’. Furthermore, this paper asks whether this new way of working empowers midwives, women, both or neither?
CELL DIVISION AND FILAMENT FORMATION IN THE DESMIDBAMBUSINA BREBISSONII(CHLOROPHYTA)1
Authors: Krupp Jonathan M. , Lang Norma J. 
Published: August 2010

ABSTRACTCell division and semicell expansion in the filamentous desmidBambusina brebissoniiKütz. were investigated using transmission and scanning electron microscopy. Interphase cells are typical of desmids, containing a full complement of organelles and a cell wall penetrated by complex pores, but the cells lack a well‐defined median constriction. Cell division involves an open spindle and the centripetal growth of a primary septum formed by the fusion of small, dark‐staining vesicles probably derived from dictyosomes. Telophase nuclei are separated by a system of interzonal microtubules and numerous large, lighter‐staining vesicles also derived from the dictyosomes. Following cell division, an elaborate replicate cross wall is formed which consists of both primary and secondary wall layers. During semicell expansion, a portion of the primary wall splits apart as the new semicells evaginate and expand to their full size. The primary wall stops splitting at a thick ring of secondary wall material leaving the cells united by the remaining common layer of primary wall. When semicell expansion is completed, the primary wall is not shed from the lateral walls of the new semicells, and pores through both primary and secondary wall layers begin to produce sheath material. However, pores in the end walls of cells do not function unless the filament is broken. The intact primary wall between cells and the absence of sheath production between cells comprise the mechanism serving to hold the cells ofBambusina brebissoniitogether in long filaments.
INTERACTIONS OF LIGHT/DARK CYCLES AND NITROGEN PULSES ON THE TIMING OF CELL DIVISION IN THE NITROGEN‐LIMITED MARINE DIATOM CYLINDROTHECA FUSIFORMIS (BACILLARIOPHYCEAE)1
Authors: Plumley F. Gerald , Darley W. Marshall 
Published: August 2010

ABSTRACTCell division in most eukaryotic algae grown on alternating periods of light and dark (LD) is synchronized or phased so that cell division occurs only during a restricted portion of the LD cycle. However, the phase angle of the cell division gate, the time of division relative to the beginning of the light period, is known to be affected by growth conditions such as nutrient status and temperature. In this study, it is shown that the phase angle of cell division in a diatom, Cylindrotheca fusiformis Reimann and Lewin, is affected by the N‐limited growth rate; cell division occurred later in the dark period (12:12 h LD cycle) when the growth rate was infradian (D = 0.42 d−1) than when it was ultradian (D = 1.0 d−1). Nitrogen‐pulses did not affect the phase angle of the division gate, but could shift the time of peak cell division activity within the division gate. The effects, if any, of N‐pulses were dependent upon the growth rate and the time of day that the pulses were administered. These responses indicate that the timing of cell division in this diatom is not determined solely by the zeitgeber from the LD cycle, but rather that a LD cycle control mechanism and a N‐mediated control mechanism are both involved and are somewhat interdependent. In addition, an increase in protein was observed immediately after administering a N‐pulse to C. fusiformis in the ultradian growth mode indicating that the accumulation of protein can be uncoupled from the cell division cycle.
COLONIZATION OF THE EPINEUSTON BY CYSTODINIUM BATAVIENSE(DINOPHYCEAE): BEHAVIOR OF THE ZOOSPORE1
Authors: Timpano Peter , Pfiester Lois A. 
Published: August 2010

ABSTRACT Cystodinium bataviense Klebs is the first dinoflagellate observed to exhibit specialized zoospore behavior which results in colonization of the epineuston. The zoospore: (1) is strongly phototactic; (2) changes shape rapidly upon release; (3) possesses at least two types of swimming behavior, including a “stop mechanism”; and, (4) sheds its theca as the new cell wall asymmetrically elongates into the immobile vegetative stage. These features working in concert facilitate the entrance of Cystodinium into the epineuston. Detailed observations of zoospore morphology and analysis of its behavior are used as new characters to further delimit C. bataviense. Since vegetative morphology has proven unsatisfactory in circumscribing other Cystodinium species, the study of variation in zoospore characters will help to clarify taxonomic units within the genus.
KINETICS OF PHOSPHATE TRANSPORT BY SYNECHOCOCCUS LEOPOLIENSIS (CYANOPHYTA): EVIDENCE FOR DIFFUSION LIMITATION OF PHOSPHATE UPTAKE1
Authors: Mierle Greg 
Published: August 2010

ABSTRACTThe kinetics of phosphate transport by Synechococcus leopoliensis (Racih.) Komarek was investigated. Deviations from Michaelis‐Menten kinetics were observed at law concentrations of phosphate and the deviations were consistent with diffusion limitation of transport. Activation energy analysis of the transport process at two concentrations, one at carrier saturation and the other at zero added phosphate yielded activation energies of 11.9 and 5.6 kcal/mole respectively at 25° C. The first is consistent with an enzyme limited process and the second with diffusion limitation through the unstirred layer.
ULTRASTRUCTURE OF AUXILIARY AND GONIMOBLAST CELLS DURING CARPOSPOROPHYTE DEVELOPMENT IN FAUCHEOCOLAX ATTENUATA (RHODOPHYTA)1
Authors: Kugrens Paul , Delivopoulos Stylianos G. 
Published: August 2010

ABSTRACTThe ultra structure of post‐fertilization development in Faucheocolax attenuata Setch. is described. Following fertilization and transfer of the diploid nucleus to the auxiliary cell, four gonimoblast initials usually are produced of the multinucleate auxiliary cell. Gonimoblast initials originally are uninucleate but undergo karyokinesis to form multinudeate gonimoblast cells. Terminal or generative gonimoblast cells cleave successively to form lobes of incipient carpospores, with each group of spores differentiating synchronously. Portions of the initial generative gonimoblast cells, however, remain to resume karyokinesis and repeat the process of cleavage into carpospores. Axial gonimoblast cells are transformed into secretory cells, which produce mucilage. Generative gonimoblast cells and auxiliary cells are similar in cellular structure. Both contain typical red algal proplastids, some dictyosomes, cytoplasmic concentric membranes, and numerous small vesicles. In addition, dark staining spherical masses, occurring in the cytoplasm of all cell types, may represent dehydrated haploid chromatin. Large septal plugs interconnect gonimoblast cells and the auxiliary cell. These plugs are small when first formed but increase dramatically in size during carposporophyte development.
CELL DIVISION AND THE ROLE OF THE PRIMARY WALL IN THE FILAMENTOUS DESMIDONYCHONEMA LAEVE(CHLOROPHYTA)1
Authors: Krupp Jonathan M. , Lang Norma J. 
Published: August 2010

ABSTRACTCell division and the role of the primary wall in filament formation in the desmidOnychonema laeveNordst. were investigated by transmission and scanning electron microscopy. In addition, sequential chemical extractions and enzyme treatments were performed, on cell walls of intact filaments. Interphase cells are deeply constricted, consisting of two semicells, each elliptical in front view and circular in side view. In addition to two short lateral spines, each semicell has two apical processes that originate on opposite sides at an angle of about 15° from the central axis and overlap the adjacent cell. Division is initiated as in other desmids by a slight separation of the semicells and development of a girdle of primary wall material at the isthmus. InO. laevethe girdle of primary wall expands to form a spherical vesicle (termed a division vesicle) between the separating semicells. Nuclear division and septum formation occur in this vesicle when it is nearly the full diameter of the filament. Morphogenesis of the apical processes begins with completion of the septum, before the secondary wall appears. At maturity each apical process is surrounded by a thick layer of both secondary and primary wall, except that its capitate tip protrudes through the shroud of primary wall. Sequential treatment with hot ammonium oxalate, 4% NaOH, 17.5% NaOH and 10% chromic acid or various enzyme solutions did not cause filament breakage. SEM and TEM views ofO. laeveafter these treatments show intact secondary walls and intact primary wall material covering and connecting the apical processes of adjacent cells. It is the persistence of the primary wall between cells and around the apical processes that maintains the long, unbranched filamentous morphology ofOnychonema laeve.
THE INFLUENCE OF SEA ANEMONES ON THE MORPHOLOGY AND PRODUCTIVITY OF TWO INTERTIDAL SEAWEEDS1
Authors: Taylor Phillip R. 
Published: August 2010

ABSTRACTThe intertidal seaweeds Corallina vancouveriensis Yendo and Gelidium coulteri Harv. respond to the experimental removal of associated mats of the clonal anemone Anthopleura elegantissima Brandt with morphological changes that affect their photosynthetic performances. With the removal of anemones, these seaweeds develop a tight compaction of thalli which aids in the retention of moisture during aerial exposure. The morphological response, however, results in greatly reduced net photosynthesis in C. vancouveriensis (–98%) and G. coulteri (–73%) on an areal basis. Association with the clonal anemones allows these seaweeds to maintain a morphology that is more highly productive yet inconsistent with the exposure stresses in many microhabitats at similar tidal levels.
BACTERIAL INFLUENCE UPON GROWTH AND HYDROCARBON PRODUCTION OF THE GREEN ALGABOTRYOCOCCUS BRAUNII1
Authors: Chirac Christian , Casadevall Eliette , Largeau Claude , Metzger Pierre 
Published: August 2010

ABSTRACTBatch cultures of the hydrocarbon‐rich algaBotryococcus braunii,Kütz. (axenic strains, non‐axenic strains, associations with selected microorganisms) were examined with regard to total biomass and hydrocarbons at the onset of the stationary phase. Pronounced variations, related to the origin of the strains and to growth conditions, were observed with axenic cultures. It also appeared that the presence of microorganisms is not essential for high hydrocarbon production. Nevertheless, numerous bacteria were shown to exert considerable influence, antagonistic or beneficial, onB. brauniigrowth yield and hydrocarbon production. Such effects were strongly dependent on the species involved and on culture conditions. The presence of various microorganisms can influence not only the quantity of hydrocarbons produced, but also their level in the algal biomass and their relative abundance. However, their chemical structure is not affected. Intricate relationships were observed inB. braunii‐bacteria systems and numerous factors (including, in some cultures, large positive effects due to bacterially produced CO2) were implicated. Accordingly, specific associations should provide appropriate conditions for renewable hydrocarbon production viaB. brauniilarge scale cultures.
SPORE FORMATION IN THE LIFE CYCLES OF THE DIATOMS CHAETOCEROS DIADEMA AND LEPTOCYLINDRUS DANICUS1
Authors: French Fred W. , Hargraves Paul E. 
Published: August 2010

ABSTRACTA nitrogen limitation technique elicited the entire life cycle of the marine centric diatoms Chaetoceros diadema (Ehr.) Gran and Leptocylindrus danicus Cleve. In C. diadema the sexual cycle followed the same pattern as in the previously investigated C. didymus. Sexuality took place in narrow diameter cells, only at 2 and 5° C, and was seldom seen. Resting spore formation took place in cells of all sizes and at all temperatures at which the species grew vegetatively (2–15° C). The L. danicus life cycle is probably unique among diatoms. Nitrogen depletion induced sexuality in the entire culture at 10 and 15° C if the cell diameter was narrow (3–8 μm). Auxospore formation was followed by resting spore formation directly within the auxospore. In C. diadema, as in most centric diatoms, resting spores are not an obligate part of the life cycle, but they are in L. danicus. Resting spore formation is a versatile adaptive response in C. diadema, depending only on nitrogen depletion, although promoted by low temperatures. In L. danicus the linkage to the sexual process sharply limits conditions under which resting spores can form.
MITOSIS AND CELL DIVISION IN CYLINDROCAPSA GEMINELLA (CHLOROPHYCEAE)1
Authors: Sluiman Hans J. 
Published: August 2010

ABSTRACTMitosis and cell division were studied in the green alga Cylindrocapsa geminella Wolle with transmission electron microscopy. Vegetative cells possess a parietal, lobed chloroplast, and a central pyrenoid. Prophase and metaphase nuclei are surrounded by 1–3 layers of perinuclear endoplasmic reticulum. At early prophase a small number of perinuclear microtubules (MTs) are present while at late prophase MTs are concentrated at the presumptive spindle poles. At the same time, MTs begin to appear in the nucleoplasm. Metaphase spindles are diamond‐shaped and centric. During telophase, centrioles migrate towards the center of the equatorial zone, presumably guided by a small group of perinuclear MTs. A second system of MTs develops in the equatorial plane, initially consisting of randomly orientated microtubular elements. Later they tend to run in a predominantly radial direction although a common MT focal point or organizing center is not apparent. The two centriole complexes remain at the center of the equatorial plane until well into interphase, facing each other across the newly formed transverse septum. Centrioles are associated with root templates and connecting fibers. The present observations corroborate the view that C. geminella does not form a true filament in the ulotrichalean or chaetophoralean sense, but rather consists of a row of autospores. Its affinity with other “pseudo‐filamentous” green algae and the Chlorococcales is discussed. The interpretation of the cytokinetic MTs in C. geminella as a phycoplast appears to be problematic.