Vertical Stem Research Articles

Transition from a hysteresis-like to an exchange-bias-like response of an uncompensated antiferromagnet

Highly Co-doped ZnO shows uncompensated antiferromagnetic order and a vertical exchange bias shift even in the absence of a ferromagnet. Therefore, it is an ideal model system to study the behavior of uncompensated antiferromagnetic moments, which play a crucial role in the description of conventional exchange bias. Temperature- and cooling-field-dependent magnetometry measurements provide further information on the compensated and uncompensated antiferromagnetic configurations in Co-doped ZnO, revealing that observed effects of both vertical exchange shift and open hysteresis stem from similar magnetic configurations. This transition is evidenced by the increase of the vertical exchange shift on the expense of the hysteresis opening by lowering the temperature.

Viking Ships with Angular Stems: Did the Old Norse term beit refer to early sailing ships?

This article discusses a certain type of ship known from Scandinavian Viking Age and Merovingian Period iconography. This type of ship has a vertical stem and stern that meet the keel at right angles, sometimes with an extension filling the space under a sloping forefoot and a similar extension at the rear end of the keel. This design seems to be connected with the earliest sailing ships and it has been suggested that the extensions were invented to meet the increased need for lateral resistance when sailing. Additional arguments for this view are explored which suggest that this design was a transitional stage between rowing ships with steering oars at both ends and specialized sailing ships with more sophisticated designs for sideways resistance: the extensions are the steering oars’ anti-leeway properties ‘built into the hull’. The authors also suggest that this type of ship was referred to in Old Norse as beit, which is a term that seems to date from the Early Viking Age. In Modern Norwegian, lobeit ‘windward beit’ refers to a ship's ability to avoid leeway and is probably related to the verb beita ‘to sail upwind’, which seems to derive from a comparison of the keel with a cutting tool. This would fit well with the discussed ship type and its extensions.

Therapeutic efficacy of Mirena in gynecologic disease

The levonorgestrel-releasing intrauterine system (LNG-IUS) was originally developed as a method of contraception and was first marketed in Finland in 1990. In Korea, the only LNG-IUS approved for non-contraceptive use is Mirena, a T-shaped device with a vertical stem containing a reservoir of 52 mg of levonorgestrel, which releases 20 µg of levonorgestrel per day. The device's strong local effects on the endometrium benefit women with gynecological conditions such as heavy menstrual bleeding, dysmenorrhea, leiomyoma, adenomyosis, and endometriosis. There is also evidence to support its role in endometrial protection during postmenopausal estrogen therapy and in the treatment of endometrial hyperplasia without atypia and, possibly, early endometrial cancer. Because of its effectiveness, safety, and high patient satisfaction, the LNG-IUS will continue to provide important benefits in women's reproductive health.

Conducting Elevated Temperature Normal and Combined Pressure-Shear Plate Impact Experiments Via a Breech-end Sabot Heater System.

A novel approach for conducting normal and/or combined pressure-shear plate impact experiments at test temperatures up to 1000 °C is presented. The method enables elevated temperature plate-impact experiments aimed towards probing dynamic behavior of materials under thermomechanical extremes, while mitigating several special experimental challenges faced while performing similar experiments using the conventional plate impact approach. Custom adaptations are made to the breech-end of a single-stage gas-gun at Case Western Reserve University; these adaptations include a precision-machined extension piece made from SAE 4340 steel, which is strategically designed to mate the existing gun-barrel while providing a high tolerance match to the bore and keyway. The extension piece contains a vertical cylindrical heater-well, which houses a heater assembly. A resistive coil heater-head, capable of reaching temperatures of up 1200 °C, is attached to a vertical stem with axial/rotational degrees of freedoms; this enables thin metal specimens held at the front-end of a heat-resistant sabot to be heated uniformly across the diameter to the desired test temperatures. By heating the flyer plate (in this case, the sample) at the breech-end of the gun-barrel instead of at the target-end, several critical experimental challenges can be averted. These include: 1) severe changes in the alignment of the target plate during heating due to the thermal expansion of the several constituents of the target holder assembly; 2) challenges that arise due to the diagnostics elements, (i.e., polymer holographic gratings, and optical probes) being too close to the heated target assembly; 3) challenges that arise for target plates with an optical window, where crucial tolerances between the sample, bond layer, and window become increasingly difficult to maintain at high temperatures; 4) in the case of combined compression-shear plate impact experiments, the need for high-temperature resistant diffraction gratings for the measurement of transverse particle velocity at the free surface of the target; and 5) limitations imposed on the impact velocity necessary for unambiguous interpretation of the measured free surface velocity versus time profile due to thermal softening and possibly yielding of the bounding target plates.By utilizing the adaptations mentioned above, we present results from a series of reverse geometry normal plate impact experiments on commercial purity aluminum at a range of sample temperatures. These experiments show decreasing particle velocities in the impacted state, which are indicative of material softening (decrease in post-yield flow stress) with increasing sample temperatures.

Differential manipulation of leaf angle throughout the canopy: current status and prospects.

Leaf angle is defined as the inclination between the midrib of the leaf blade and the vertical stem of a plant. This trait has been identified as a key component in the development of high-yielding varieties of cereal species, particularly maize, rice, wheat, and sorghum. The effect of leaf angle on light interception efficiency, photosynthetic rate, and yield has been investigated since the 1960s, yet, significant knowledge gaps remain in understanding the genetic control of this complex trait. Recent advances in physiology and modeling have proposed a plant ideotype with varying leaf angles throughout the canopy. In this context, we present historical and recent evidence of: (i) the effect of leaf angle on photosynthetic efficiency and yield; (ii) the hormonal regulation of this trait; (iii) the current knowledge on its quantitative genetic control; and (iv) the opportunity to utilize high-throughput phenotyping methods to characterize leaf angle at multiple canopy levels. We focus on research conducted on grass species of economic importance, with similar plant architecture and growth patterns. Finally, we present the challenges and strategies plant breeders will need to embrace in order to manipulate leaf angle differentially throughout the canopy and develop superior crops for food, feed, and fuel production.

Analysis of Stem Wave due to Long Breakwaters at the Entrance Channel

Recently, a new port reserves deep water depth for safe navigation and mooring, following the trend of larger ship building. Larger port facilities include long and huge breakwaters, and mainly adopt vertical type considering low construction cost. A vertical breakwater creates stem waves combining inclined incident waves and reflected waves, and this causes maneuvering difficulty to the passing vessels, and erosion of shoreline with additional damages to berthing facilities. Thus, in this study, the researchers have investigated the response of stem waves at the vertical breakwater near the entrance channel and applied numerical models, which are commonly used for the analysis of wave response at the harbor design. The basic equation composing models here adopted both the linear parabolic approximation adding the nonlinear dispersion relationship and nonlinear parabolic approximation adding a linear dispersion relationship. To analyze the applicability of both models, the research compared the numerical results with the existing hydraulic model results. The gap of serial breakwaters and aligned angles caused more complicated stem wave generation and secondary stem wave was found through the breakwater gap. Those analyzed results should be applied to ship handling simulation studies at the approaching channels, along with the mooring test.

3C-SiC microdisk mechanical resonators with multimode resonances at radio frequencies

We report on the design, modeling, fabrication and measurement of single-crystal 3C-silicon carbide (SiC) microdisk mechanical resonators with multimode resonances operating at radio frequencies (RF). These microdisk resonators (center-clamped on a vertical stem pedestal) offer multiple flexural-mode resonances with frequencies dependent on both disk and anchor dimensions. The resonators are made using a novel fabrication method comprised of focused ion beam nanomachining and hydroflouic : nitric : acetic (HNA) acid etching. Resonance peaks (in the frequency spectrum) are detected through laser-interferometry measurements. Resonators with different dimensions are tested, and multimode resonances, mode splitting, energy dissipation (in the form of quality factor measurement) are investigated. Further, we demonstrate a feedback oscillator based on a passive 3C-SiC resonator. This investigation provides important guidelines for microdisk resonator development, ranging from an analytical prediction of frequency scaling law to fabrication, suggesting RF microdisk resonators can be good candidates for future sensing applications in harsh environments.

Anisotomous dichotomy results from an unequal bifurcation of the original shoot apical meristem in Diphasiastrum digitatum (Lycopodiaceae).

Two types of dichotomy are recognized in Lycopodiaceae: isotomous (equal) and anisotomous (unequal). Anisotomous dichotomy (anisotomy) has been hypothesized to result from unequal growth of an equal bifurcation of the original shoot apical meristem (SAM). Diphasiastrum digitatum (Lycopodiaceae) exhibits anisotomy at various locations. We thus used D. digitatum to test this classic hypothesis about anisotomy. Transverse areas of original and derived SAMs of anisotomy exhibited by the rhizome and the vertical aerial vegetative stem were measured using scanning electron microscopy. The difference between half of the original SAM and one derived SAM in terms of transverse area were compared using paired t-tests. During the anisotomy exhibited by the rhizome SAM, 77.4% of the transverse area of the original rhizome SAM contributed to the derived rhizome SAM. During the first anisotomy exhibited by the vertical aerial vegetative stem SAM, 66.2% of the transverse area of the original vertical aerial vegetative stem SAM contributed to the derived vertical aerial vegetative stem SAM. During the second anisotomy exhibited by the vertical aerial vegetative stem SAM, 49.4% of the transverse area of the original vertical aerial vegetative stem SAM contributed to the derived vertical aerial vegetative stem SAM. Nonetheless, the shape of the two derived SAMs differed though they did not differ in size. In D. digitatum, anisotomy results from an unequal bifurcation of the original SAM. This finding sheds light on plant body architecture evolution as well as plant organ (megaphyllous leaf) evolution.

Waste Water Purification By TiO2 anodically Grown in Different Geometries

The effectiveness of TiO2 to degrade organic pollutants, and its viability as water treatment technology has already been demonstrated. Nonetheless, most studies use TiO2 nanoparticles, which hinders its application at industrial scale due to economical and operational issues like recovering the catalyst after the treatment. The growth of immobilized TiO2 nanostructures by anodic oxidation seems a solution to this problem. However, the lack of reproducibility and poor understanding of the process has been the main drawback for its application at industrial scale. In the present work, the photocatalytic degradation of two commercial textile dyes in aqueous solutions (Rhodamine B and Methylene blue) was studied with three different types of immobilized TiO2 nanostructures and two different geometries (i.e. foil and net). These nanostructures were produced by anodic oxidation in the form of either nanotubes or nanoporous ASD coatings with good adherence, high aspect ratio and good spatial uniformity. Commercial purity titanium sheets were anodized in three different electrolytes: aqueous solution (ASD), fluoride containing aqueous solution (A-NT) and fluoride containing organic solution (O-NT). The surface pre-treatment, anodizing temperature and time, were changed, in order to obtain the best nanostructures in each electrolyte. After anodizing in solutions containing fluorides, samples were annealed at different temperatures and times to promote the formation of anatase phase TiO2 and to evaluate the influence of these parameters in the photocatalytic activity of the samples. These nanostructures were characterized by SEM and Raman spectroscopy. The degradation of Rhodamine B (RhB) and Methylene Blue (MB), pure or mixed, was performed by immersing a sample (6 cm2) in 25 ml of 10-5 M RhB solution and/or 1.25X10-4 M MB solution, respectively, irradiating for 6 h with a solar spectrum lamp (UV-A 3 mW/cm2) and monitoring color variations which represent dye degradation. In aqueous and organic solutions containing fluorides, self-aligned vertical nanotubes stem from the substrate; in organic solution the detachment of single nanotubes is less pronounced, creating a sort of porous template rather than a nanotubular array, but with higher thickness and better photoactivity efficiency. Conversely, in absence of fluorides and with the application of a larger cell voltage, an oxide with glassy appearance and larger pores is generated, with a photoactivity comparable to that obtained with the nanotubes growth in aqueous electrolyte. The photocatalytic degradation of dyes with these oxides increases when a chemical etching is applied as surface treatment before the anodization. At lower anodizing temperatures (5-7 ˚C) and times, a decrease in the photoactivity is obtained. The annealing process to crystallize the oxide in the nanotubular structures give the best results in terms of crystallinity and integrity of the nanotubes at 500 ˚C for 2 h. Both types of sample geometries (foil and net) show a good photoactivity, which allows more alternatives in the development and configuration of photocatalytic reactors. When mixes of the two dyes are used, a slight decrease in the kinetic of degradation is observed with respect to their pure forms, which may reduce photocatalytic efficiency in complex industrial wastewaters that generally contain more than one pollutant. In conclusion, the processes here described open the way to the production of photocatalytically efficient nanostructured TiO2 films immobilized onto a metallic substrate at low cost with different geometries, avoiding environmental issues related to the use and recycle of conventional non-immobilized photocatalysts, and allow the development of photocatalytic reactors with different configurations.

Dynamics of runoff and sediment trapping performance of vegetative filter strips: Run-on experiments and modeling

Vegetative filter strips (VFSs) are a labor-saving and cost-effective agricultural best management practice to trap water runoff and sediment from the source areas. They also provide forage and/or fuel and are therefore potentially profitable for land owners. VFSs are however a dynamic system: the runoff delivery ratio (RDR) and sediment delivery ratio (SDR) vary with growth stage and vegetation types. The impacts of vegetation characteristics as well as soil physical properties modified by vegetation growth, on the RDR and SDR of VFS were evaluated by a flume experiment. Two plant species (cocksfoot (Dactylis glomerata L.) and white clover (Trifolium repens L.)) were tested at three stages in the growing season of 2016 (May, July, and August). The measured RDR and SDR were compared with the simulated results from Vegetative Filter Strip Modeling System (VFSMOD). In the early stages of the growing season, the cocksfoot formed a dense network of stems with high strip Manning's roughness faster than white clover. The runoff and sediment trapping effects of the white clover VFS were greater than that of cocksfoot VFS in all the three stages (lower RDR and SDR). This is likely attributed to strongly tillering, creeping stem posture and high infiltration capacity of the white clover VFS. VFSMOD simulated the RDR and SDR reliably except under low vegetation coverage conditions (white clover in May). The results suggested that (1) both soil physical properties and vegetation characteristics should be considered for the species-specific, temporally variable performance of VFS; and (2) when using VFSMOD inform the VFS design, modelers should take the dynamics of vegetation, mainly through vertical saturated hydraulic conductivity, stem spacing and strip Manning's roughness into account, and select parameters that reflect the actual field conditions.

The role of levonorgestrel intrauterine systems in the treatment of symptomatic fibroids

Uterine fibroids are considered to be the most frequently occurring tumours in females. The majority of fibroids do not require any treatment. When symptomatic, the major ailments include abnormal uterine bleeding, painful menstruation, pelvic pressure or pain, urinary problems, constipation, infertility, and recurrent pregnancy loss. Surgery remains a mainstay of symptomatic uterine fibroids therapy; however, minimally-invasive techniques and pharmacological management have become more available. The levonorgestrel intrauterine system (LNG-IUS) is a T-shaped device with a vertical stem containing a reservoir of levonorgestrel and is widely known for its contraception effect. Moreover, the non-contraceptive benefits of the LNG-IUS have been previously confirmed by numerous studies. LNG-IUS causes reduction of the duration and the amount of menstrual bleeding, with minimal side effects due to release of hormones at the targeted organ. Currently, results from systematic reviews show that LNG-IUS may be an effective and safe treatment for symptomatic uterine fibroids in premenopausal women. However, further studies are required to consolidate the usage of LNG-IUS in the treatment of symptomatic uterine fibroids.

Validation of Reference Genes for Gene Expression by Quantitative Real-Time RT-PCR in Stem Segments Spanning Primary to Secondary Growth in Populus tomentosa.

The vertical segments of Populus stems are an ideal experimental system for analyzing the gene expression patterns involved in primary and secondary growth during wood formation. Suitable internal control genes are indispensable to quantitative real time PCR (qRT-PCR) assays of gene expression. In this study, the expression stability of eight candidate reference genes was evaluated in a series of vertical stem segments of Populus tomentosa. Analysis through software packages geNorm, NormFinder and BestKeeper showed that genes ribosomal protein (RP) and tubulin beta (TUBB) were the most unstable across the developmental stages of P. tomentosa stems, and the combination of the three reference genes, eukaryotic translation initiation factor 5A (eIF5A), Actin (ACT6) and elongation factor 1-beta (EF1-beta) can provide accurate and reliable normalization of qRT–PCR analysis for target gene expression in stem segments undergoing primary and secondary growth in P. tomentosa. These results provide crucial information for transcriptional analysis in the P. tomentosa stem, which may help to improve the quality of gene expression data in these vertical stem segments, which constitute an excellent plant system for the study of wood formation.

Protected cropping for specialty melons in North Queensland

Protective cropping could be an effective system for growing specialty melons in the dry tropics of North Queensland. The growing system could reduce outdoor risks for production loss, improve fruit quality, increase yield per m2, allow production offseason, and used for supplying niche markets in a segment of the larger melon market in Australia. First evaluations in Giru, Queensland, included seven cultivars of fruit types 'Galia', 'Hami', 'Charentais', small 'Canary', and 'Rockmelon', transplanted July 25, 2013 under a high polyethylene-covered tunnel. Plants were grown at a density of 2.8 plants m-2 in containers filled with volcanic rock and irrigated with a complete nutrient solution. Pruning and trellising was done to a single vertical stem, keeping lateral shoots on the main stem after the 7th leaf node. After bearing small fruit, lateral shoots were cut off after their second or third leaf node. To facilitate insect pollination, a screen window in the tunnel was left partially opened. On November 20 the cultivars had combined marketable yields that ranged from 2.8 to 8.2 fruits m-2 and 3.1 to 7.8 kg m-2. Total soluble solids levels in fruit ranged from 6 to 13 °Brix. Cultivars 'Tempo' ('Galia'), 'Tikal' ('Canary') and 'Sultan' ('Charentais') had fruit yields that were up to 2.6 times greater than yields commonly achieved with field-grown rockmelon crops. Sugar levels in fruits and marketable yields may be increased with changes in fertigation management. Promising results in this first evaluation justify examination of a greater number of genetic materials, in addition to the development of economic feasibility studies and further adaptive research to refine crop recommendations for growing melons in protective cropping systems.

ANATOMY AND CHEMICAL COMPOSITION OF LIRIODENDRON TULIPIFERA STEMS INCLINED AT DIFFERENT ANGLES

The anatomical and chemical characteristics of reaction wood (RW) were investigated in Liriodendron tulipifera Linn. Stems of seedlings were artificially inclined at angles of 30 (RW-30), 50 (RW-50) and 70° (RW-70) from the vertical, and compared with normal wood (NW) from a vertical seedling stem. The smallest values for the wood fibre length and vessel number were observed in RW-50. The pit aperture angle was less than 10° in RW-30 and RW-50, in which reduced lignin content was observed in the S2 layer of the wood fibres. An increase in the glucose content and a decrease in the lignin and xylose content was observed in RW-50. The stem inclination angle affected the degree of RW development with regard to anatomical and chemical characteristics: the severest RW was observed in RW-50, followed by RW-30. RW-70 was similar in anatomical and chemical characteristics to NW, apparently because the inclination was too strong to enable recovery of its original position. In this case a vertical sprouting stem was formed to replace the inclined stem.

Controllable Fabrication of Networked Three-Dimensional Nanoporous Anodic Alumina Films on Low-Purity Al Materials

Networked three-dimensional (3D) nanoporous alumina nanostructures—consisting of vertical cylindrical stem pore arrays (170–310 nm in diameter) and periodical transverse branched pores (20–80 nm in diameter) interspaced regularly by 190–220 nm across the vertical pore walls—were controllably fabricated from low purity Al materials (99.0%, 99.3%, and 99.56%) by anodization in a phosphoric acidic solution at 110–190 V. The formation of transverse pores depended predominantly on the purity of the Al base materials and the corrosion resistance of the anodic porous alumina films, which can be mainly attributed to anodic and/or chemical dissolution of impurities such as Fe, Cu, Zn, Mg, and Mn incorporated in the Al base materials. Moreover, the effects of the purity of Al materials on the growth and morphology of porous alumina films in oxalic and sulfuric acid solutions were also investigated by a two-step anodization of Al sheets with different purities, namely 99.0%, 99.3%, 99.56%, and 99.999% Al. The alumina films grew more slowly in all electrolytes with decreasing Al purity, which can be attributed to the lower corrosion resistance of the PAA films containing small quantities of Fe oxides and/or hydroxides produced during anodization.

Modeling the effects of growth rate on the intra-tree variation in basic density in hinoki cypress (Chamaecyparis obtusa)

The purpose of this study is to evaluate the effect of growth rate on intra-tree variation in basic density of hinoki cypress (Chamaecyparis obtusa) quantitatively using the statistical modeling technique. Nineteen sample trees were harvested from 50-year-old hinoki stand which consists of two different growth rate plots. Disks were cut from sample trees at height positions of 2, 4 m, and then 4 m intervals until 16 m position. Radial strips were cut from the disks, and ring widths and basic density were measured at 5-ring intervals. The basic density decreased with age at any height positions. The linear mixed model was fitted to the age trend data having two nested grouping levels, i.e., tree and position within tree. Models having various mean and covariance structures were tested in devising an appropriate wood density model. The model, consisting of the mean structure with quadratic function of cambial age was able to describe the intra-tree variation in basic density. The model containing the random effects which consist of effect of the tree level and vertical stem position level explained the density variation adequately. The growth rate did not show the significant effect on the basic density variation within the stem.

Numerical modeling on progressive internal deformation in down-built diapirs

A two-dimensional finite difference code (FDCON) is used to estimate the finite deformation within a down-built diapir. The geometry of the down-built diapir is fixed by using two rigid rectangular overburden units which sink into a source layer of a constant viscosity. Thus, the model refers to diapirs consisting of a source layer feeding a vertical stem, and not to other salt structures (e.g. salt sheets or pillows). With this setup we study the progressive strain in three different deformation regimes within the “salt” material: (I) a squeezed channel-flow deformation regime and (II) a corner-flow deformation regime within the source layer, and (III) a pure channel-flow deformation regime within the stem. We analyze the evolution of finite deformation in each regime individually, progressive strain for particles passing all three regimes, and total 2D finite deformation within the salt layer. Model results show that the material which enters the stem bears inherited strain accumulated from the other two domains. Therefore, finite deformation in the stem differs from the expected channel-flow deformation, due to the deformation accumulated within the source layer. The stem displays a high deformation zone within its center and areas of decreasing progressive strain between its center and its boundaries. High deformation zones within the stem could also be observed within natural diapirs (e.g. Klodowa, Polen). The location and structure of the high deformation zone (e.g. symmetric or asymmetric) could reveal information about different rates of salt supplies from the source layer. Thus, deformation pattern could directly be correlated to the evolution of the diapir.

Multi-Polarization ASAR Backscattering from Herbaceous Wetlands in Poyang Lake Region, China

Wetlands are one of the most important ecosystems on Earth. There is an urgent need to quantify the biophysical parameters (e.g., plant height, aboveground biomass) and map total remaining areas of wetlands in order to evaluate the ecological status of wetlands. In this study, Environmental Satellite/Advanced Synthetic Aperture Radar (ENVISAT/ASAR) dual-polarization C-band data acquired in 2005 is tested to investigate radar backscattering mechanisms with the variation of hydrological conditions during the growing cycle of two types of herbaceous wetland species, which colonize lake borders with different elevation in Poyang Lake region, China. Phragmites communis (L.) Trin. is semi-aquatic emergent vegetation with vertical stem and blade-like leaves, and the emergent Carex spp. has rhizome and long leaves. In this study, the potential of ASAR data in HH-, HV-, and VV-polarization in mapping different wetland types is examined, by observing their dynamic variations throughout the whole flooding cycle. The sensitivity of ASAR backscattering coefficients to vegetation parameters of plant height, fresh and dry biomass, and vegetation water content is also analyzed for Phragmites communis (L.) Trin. and Carex spp. The research for Phragmites communis (L.) Trin. shows that HH polarization is more sensitive to plant height and dry biomass than HV polarization. ASAR backscattering coefficients are relatively less sensitive to fresh biomass, especially in HV polarization. However, both are highly dependent on canopy water content. In contrast, the dependence of HH- and HV- backscattering from Carex community on vegetation parameters is poor, and the radar backscattering mechanism is controlled by ground water level.

Exogenously applied 24-epi brassinolide reduces lignification and alters cell wall carbohydrate biosynthesis in the secondary xylem of Liriodendron tulipifera

The roles of brassinosteroids (BRs) in vasculature development have been implicated based on an analysis of Arabidopsis BR mutants and suspension cells of Zinnia elegans. However, the effects of BRs in vascular development of a woody species have not been demonstrated. In this study, 24-epi brassinolide (BL) was applied to the vascular cambium of a vertical stem of a 2-year-old Liriodendron, and the resulting chemical and anatomical phenotypes were characterized to uncover the roles of BRs in secondary xylem formation of a woody species. The growth in xylary cells was clearly promoted when treated with BL. Statistical analysis indicated that the length of both types of xylary cells (fiber and vessel elements) increased significantly after BL application. Histochemical analysis demonstrated that BL-induced growth promotion involved the acceleration of cell division and cell elongation. Histochemical and expression analysis of several lignin biosynthetic genes indicated that most genes in the phenylpropanoid pathway were significantly down-regulated in BL-treated stems compared to that in control stems. Chemical analysis of secondary xylem demonstrated that BL treatment induced significant modification in the cell wall carbohydrates, including biosynthesis of hemicellulose and cellulose. Lignocellulose crystallinity decreased significantly, and the hemicellulose composition changed with significant increases in galactan and arabinan. Thus, BL has regulatory roles in the biosynthesis and modification of secondary cell wall components and cell wall assembly during secondary xylem development in woody plants.

Osteointegration of an uncemented modular revision stem implanted during revision hip surgery.

Though mid-term survival rates of over 95% in several series have been published, there is still a paucity of related literature regarding the role of vertical stem instability in the osteointegration of fluted tapered stems. This paper presents a comprehensive and prospective assessment on short-term experiences with uncemented modular femoral stem in the treatment of defective femur during revision surgery of total hip replacement. Clinical and radiological monitoring of 20 consecutive patients with implanted tapered fluted revision stem (Lima Corporate, Udine, Italy) was of 27 months in average (20-35 months). The average pre-operative Merle d'Aubigné and Postel method score was 6.3 points (3-10 points). The frequency of femur defects, classified according to Paprosky, was IIIA = 9 and IIIB = 11. During last follow-up, the Merle d'Aubigné and Postel hip score was on average 11.7 (6-16 points). Compared to post-operation radiograph, stem migration of 1.9 mm (0-11 mm) on average was found. This vertical stem migration was observed only when comparing hip radiographs immediately after surgery, and at 6 weeks post-surgery. The Paprosky IIIA defects group, presented a subsided stem by an average of 1.5 mm. In the group of Paprosky IIIB defects, the stem subsidence was on average 2.3 mm. All 20 patients in the study showed excellent osteointegration of the uncemented revision modular stem. This study found and excellent osteointegration of the Lima uncemented tapered fluted revision modular stem in defective femur with a cortical bone segment present in the diaphyseal isthmus area. The initial vertical instability leading to stem migrating during the first six weeks following surgery did not, however, affect its osteointegration.