Surface Of Lamina Research Articles

A new endemic Begonia species (sect. Knesebeckia, Begoniaceae) from the south-western montane forest remnants of Ecuador

Begonia jocotocoi is a new species described from the Buenaventura Reserve in El Oro Province, south-west Ecuador. The new species morphologically resembles Begonia serotina, but differs by its minutely bullate leaf lamina (vs. smooth), the dense red long trichomes that cover the petioles and the lower surface of the leaf lamina, the latter of which distinctly become purple at maturity (vs. usually glabrous or occasionally with an indument of minute glandular white hairs and pale green below), presence of a pair of bracteoles directly beneath the pistillate flowers (vs. bracteoles absent), and the pedicels and also sometimes the abaxial surfaces of most floral whorls having a sparse cover of glandular hairs (vs. glabrous to puberulous). Photos of the new species and a distribution map are provided. Relationships with other species are discussed and the species’ preliminary conservation status is assigned as critically endangered (CR).

Dryopteris microlepioides, a new synonym of Trichoneuron microlepioides (Dryopteridaceae)

When reviewing the species diversity of Dryopteridaceae from Vietnam, we noticed the name Dryopteris microlepioides Christensen (1934: 102) is taxonomically uncertain and to be treated (Hassler 1994–2024). Dryopteris microlepioides was described based on two collections from northern Vietnam and was thought to be a distinct species superficially resembling Microlepia speluncae (Linnaeus 1753: 1093) Moore (1857: 93) (Christensen 1934). Since its publication in 1934, this name had been neglected by authors who treated Dryopteris Adanson (1763: 20) for the fern flora or species diversity of Vietnam (e.g., Tardieu-Blot & Christensen 1938, 1941; Pham 1999; Phan 2010). At the first sight of the type specimens of D. microlepioides, the senior author (SYD) was aware of D. microlepioides representing the same taxon with Trichoneuron microlepioides Ching (1965: 119) described from southern Yunnan, China, because this taxon is morphologically unique by having the microlepioid frond habit (especially with copious pale hairs on both surfaces) and the dryopterioid sori (reniform, medial on abaxial surface of lamina) (Fig. 1). Phylogenetically, the sample of this species from northern Vietnam, which was identified as T. microlepioides by Liu et al. (2016), was resolved to be sister to Polystichopsis (Smith 1875: 217) Holttum (1947: 147) in Dryopteridaceae subfam. Polybotryoideae based on the analysis of three cpDNA sequences (rbcL, atpA, and atpB) (Liu et al. 2016). In recent years, we also collected this taxon in northern Vietnam (paratype locality of D. microlepioides) and southern Yunnan, China, and conducted phylogenetic analysis based on cpDNA genome (not presenting here). Our analysis resolved one sample from Vietnam (Dong 4598) and two collections from Yunnan (Dong 4801 and Zuo 5093) clustered together, identifying no any significant difference between them. The three samples in the phylogenetic tree formed a sister relationship in high supporting values with Polystichopsis as the result in Liu et al. (2016). This result provides further evidence supporting the same species of D. microlepioides Christensen (1934) with T. microlepioides Ching (1965).

Lateral atlanto-axial joint access using the C2 pedicle

Abstract Background Neck pain and headaches can arise from the lateral atlanto-axial (LAA) joint. This pain can be diagnosed with intra-articular injections of local anesthetic. A widely used technique for access to the lateral atlanto-axial joint uses a posterior approach, but this approach can be hazardous because of the proximity of the vertebral artery, the dural sac, and the C2 spinal nerve and dorsal root ganglion. Objective The objective was to describe and test a new technique for accessing the LAA joint that avoids structures that lie behind the joint. Interventions The new technique was described and tested for tolerance in 10 patients with unilateral suboccipital pain and tenderness over the LAA joint, along with evidence of LAA joint arthropathy on SPECT CT. The technique requires inserting a needle along a trajectory tangential to the dorsal surface of the C2 lamina. It involves obtaining a declined view of the C2 lamina and C2 pedicle. Conclusions In all cases, the C2 pedicle was easily identified and allowed the needle to pass asymptomatically underneath the neurovascular structures behind the joint. The tactile response of the lamina of C2 provided important feedback regarding needle depth caudal to the LAA joint.

The Flexural Strength of Three Bamboo Species from Brazil: A Comparative Study of Internal and External Lamina Surfaces Using Static and Dynamic Bending Properties

Bamboo is already a convenient construction resource, as it offers an efficient structural performance. As this plant has native varieties adapted to different climates and soils of Brazil, bamboo silviculture can be intensified to supply the national industry. Three bamboo species from Brazil (Dendrocalamus asper, Bambusa tuldoides, and Phyllostachys aurea) were analyzed for the flexural load capacity applied on the internal and external surfaces. Specimens were prepared without knots and with knots centered at the middle of each sample. In total, 240 samples were tested in terms of static bending and dynamic bending (impact). The results showed a higher flexural elasticity and a higher proportional limit strength of knotted P. aurea. The presence of knots provided higher values of ultimate strength in P. aurea, even reducing the bamboo flexibility. Also, P. aurea exhibited the best characteristic of flexural dynamic energy absorption among the three bamboo species under evaluation.

Morphogenesis of Hollow Bulbous Gypsum Structures Along a Brine Spring in Northeast Alberta

Abstract The stromatolite tufa mound at La Saline Lake developed along the Athabasca River Valley in northeast Alberta consists of a 30 m-high structure with a multi-meter thick caprock of stratified gypsum. The gypsum caprock developed when the meteoric-charged groundwater channeled along shallowly buried Upper Devonian limestone was redirected deeper and encountered anhydrite beds of the Middle Devonian Prairie Evaporite Formation, only 175–200 m below. Discharge of the sulfate-saturated brine from the central vent of the gypsum caprock eventually ceased and the flow was redirected to the western lakefront bank of the tufa mound. This active brine spring, characterized by total dissolved solids level of ∼79,000 mg/L, is channeled along a 25 m gully toward La Saline Lake. The bottom sediment in each of the interconnected brine pools along the gully consists of a 2–4 cm-thick calcite-gypsum thrombolite and an overlying gypsum crust. This sulfate crust developed as densely packed arrays of hollow botryoidal to hemispheroidal and bulbous gypsum protuberances, each 0.5–1.5 cm long, that extend upward into the brine. This is the first documented example of bulbous protuberances of gypsum that developed within brine pools with hollow interiors. The unusual hollowness of these bulbous gypsum protuberances resulted from the rapid encasement of gas bubbles that ascended from the underlying thrombolite ooze and were trapped within the overlying microbial mats and meshwork of gypsum crystallites on the surface of the bottom pool sediment. Nanoscale biomineralization of gypsum developed along the parallel arrays of microbial stalks within the enveloping mat, resulting in a meshwork of parallel aligned crystallites that encased the surfaces of the trapped bubbles. Continued abiotic gypsum precipitation transitioned the abiotic crystallites into enlarged needle-form crystallites distributed as parallel arrays along curvilinear growth surface laminae. Sufficient rigidity on the bubble surfaces precluded implosion-collapse or detachment. Strontium adsorption widely stabilized the acicular crystals, inhibiting complete coalescence as gypsum spar.

Combustion of iron particles in solid propellants at elevated pressure

Metal fuels, such as aluminum (Al) and iron (Fe), can be added to composite solid propellants to improve their performance, such as specific impulse, density, and burning rate. In comparison to aluminum, iron can theoretically provide improved density specific impulse and higher flame temperatures; reduce condensed combustion product (CCP) concentration and the associated two-phase flow losses; and eliminate hydrochloric acid (HCl) in the exhaust products. A fundamental and quantitative understanding of metal particle aggregation and agglomeration processes in solid propellants is required to understand the underlying combustion mechanisms in these systems. In the current study, composite strand and laminate AP/HTPB/AP propellant samples loaded with Fe microparticles (∼45 μm in diameter) were burned at elevated pressures in an optically accessible strand bomb. Combustion processes were monitored with transient pressure diagnostics and a high-speed camera fitted with a high-magnification lens system (3.83 μm/pixel resolution) for the laminate propellant experiments. An automated image processing algorithm was developed to measure burning rates and ejected particle/agglomerate sizes and velocities. Time-resolved statistical distributions of both particle size and velocity are presented at elevated pressure for multiple laminate propellant experiments with a high degree of repeatability and low measurement error estimated as < ±5% and < ±1.5% for particle size and velocity, respectively. The incorporation of iron microparticles into the composite strand propellants yielded over a 20% increase in the global burning rate over the range of pressures evaluated (3.45–13.8 MPa). Similarly, the addition of iron to the fuel lamina in laminate propellant samples led to an approximately 30% increase in the global burning rate at the evaluated pressure (3.45 MPa). Additive particles were observed to eject near the oxidizer/fuel interface, or to melt, aggregate, coalesce, and agglomerate on the fuel lamina surface prior to ejection. Particle velocities are controlled by a balance of gravitational forces, drag forces imparted by expanding combustion product gases, and particle inertia. The observed combustion enhancements are attributed to the combined effects of catalytic mechanisms, increased radiation heat transfer, and local energy release from reacting iron particles. In addition, discussions on the image processing methods developed in the current study, corresponding potential sources of error, and prospective areas of improvement are provided. The experimental approach developed enables high-speed and high-magnification visualization of propellant combustion at high pressures and can be utilized to better understand the fundamental combustion behavior of energetic systems.

Two new Western Australian species related to Hibbertia priceana (Dilleniaceae)

Hibbertia priceana is a rare species found in two localised areas in southern south-western Western Australia, near Ongerup and in the vicinity of Wickepin and Harrismith. Two new species that are morphologically similar to H. priceana but are disjunct and distinct from it are described in this paper. Hibbertia hapalophylla is a new, potentially geographically restricted and rare species first collected during botanical surveys for a mining project near Mount Holland in the Western Australian Goldfields. It was initially collected from, and only known from, disturbed areas on an active mine site, but larger populations were subsequently discovered on a nearby sandplain, from where is was likely introduced to the mine site on sand transported for construction purposes. The second new species, Hibbertia remanens, appears to be restricted to small areas of remnant vegetation near Cunderdin and Kellerberrin in the Western Australian wheatbelt. The three species differ mainly in their leaf shapes in section, with H. priceana having flat leaves with the abaxial lamina fully exposed, H. remanens having recurved leaf margins with the abaxial shallowly grooved either side of the midrib, and H. hapalophylla having strongly revolute margins with the abaxial lamina surface concealed within lacunae formed between the margins and midrib.

Nuclear shapes are geometrically determined by the excess surface area of the nuclear lamina.

Introduction: Nuclei have characteristic shapes dependent on cell type, which are critical for proper cell function, and nuclei lose their distinct shapes in multiple diseases including cancer, laminopathies, and progeria. Nuclear shapes result from deformations of the sub-nuclear components-nuclear lamina and chromatin. How these structures respond to cytoskeletal forces to form the nuclear shape remains unresolved. Although the mechanisms regulating nuclear shape in human tissues are not fully understood, it is known that different nuclear shapes arise from cumulative nuclear deformations post-mitosis, ranging from the rounded morphologies that develop immediately after mitosis to the various nuclear shapes that roughly correspond to cell shape (e.g., elongated nuclei in elongated cells, flat nuclei in flat cells). Methods: We formulated a mathematical model to predict nuclear shapes of cells in various contexts under the geometric constraints of fixed cell volume, nuclear volume and lamina surface area. Nuclear shapes were predicted and compared to experiments for cells in various geometries, including isolated on a flat surface, on patterned rectangles and lines, within a monolayer, isolated in a well, or when the nucleus is impinging against a slender obstacle. Results and Discussion: The close agreement between predicted and experimental shapes demonstrates a simple geometric principle of nuclear shaping: the excess surface area of the nuclear lamina (relative to that of a sphere of the same volume) permits a wide range of highly deformed nuclear shapes under the constraints of constant surface area and constant volume. When the lamina is smooth (tensed), the nuclear shape can be predicted entirely from these geometric constraints alone for a given cell shape. This principle explains why flattened nuclear shapes in fully spread cells are insensitive to the magnitude of the cytoskeletal forces. Also, the surface tension in the nuclear lamina and nuclear pressure can be estimated from the predicted cell and nuclear shapes when the cell cortical tension is known, and the predictions are consistent with measured forces. These results show that excess surface area of the nuclear lamina is the key determinant of nuclear shapes. When the lamina is smooth (tensed), the nuclear shape can be determined purely by the geometric constraints of constant (but excess) nuclear surface area, nuclear volume, and cell volume, for a given cell adhesion footprint, independent of the magnitude of the cytoskeletal forces involved.

Unilateral biportal endoscopic supralaminar, posterior spinous process sparing approach for en bloc cervical laminectomy in case of cervical osteochondroma causing myelopathy: A case report

Background ContextCervical osteochondroma is a rare cause of myelopathy. Traditional treatment is open laminectomy with or without fusion. There is limited literature on unilateral bi-portal endoscopic en-bloc resection of cervical osteochondroma. Study DesignWe describe a case of a 39-year-old male diagnosed with cervical compressive myelopathy. The pathologic site is located on the ventral surface of C4 lamina. Herein we describe a step-by-step method of unilateral biportal endoscopy (UBE) en-bloc resection of extra-dural sublaminar osteochondroma for patient who had cervical myeloradiculopathy. Spinous process sparing osteotomy was performed to conserve the spinous process and supraspinous ligament.. Outcome MeasuresThe patient was successfully treated via UBE and the operative time was 50 minutes with no intra-operative complications. Patient symptoms improved in the immediate postoperative period and by 3 months he regained fine motor functions of hand. ConclusionsUnilateral biportal endoscopic en bloc cervical laminectomy can effectively decompress cervical spine and remove posterior benign cervical tumor. UBE preserves musculature and posterior ligamentous complex and thus reduces postoperative neck pain and postlaminectomy kyphosis.

Effect of snap-through force location on morphing of bistable variable stiffness laminates

Unsymmetric composite laminates exhibit two or more stable states due to the presence of residual thermal stresses induced during the curing process. The paper aims to exploit the possibility of assessing the morphing behaviour of bistable composite laminates using semi-analytical and numerical models. A Rayleigh-Ritz based semi-analytical model is used to investigate the variable stiffness (VS) bistable laminates generated using curvilinear fibre alignments. The obtained results are verified using a fully non-linear numerical model developed in a commercially available finite element package. In order to identify the influence of loading location on the snap-through behaviour, a parametric study is proposed in the present research. Snap-through is achieved through transverse point loads. The novelty of this work resides on the investigation of load application location on the snap-through action where the transverse load is applied at various locations on the lamina surface. Earlier research on the morphing of bistable square composites is mainly on the application of concentrated load at the centre of the laminate geometry, which is considered as an ideal location for snap-through action. The designer may also have to choose other locations for the application of snap-through loads since the lamina centre may not be appropriate always in structural applications. Four different loading locations are selected for the present analysis, and snap-through loads are calculated to check the effect of loading location. Parametric studies are performed using the proposed semi-analytical and numerical models to investigate the effect of selected loading point positions on the snap-through process. The analysis is extended to a selected VS laminate family to understand the influence of loading point positions on the curvilinear fibre alignments.

Basalt Fiber Hybridization Effects on High-Performance Sisal-Reinforced Biocomposites.

The increasing attention given to environmental protection, largely through specific regulations on environmental impact and the recycling of materials, has led to a considerable interest of researchers in biocomposites, materials consisting of bio-based or green polymer matrixes reinforced by natural fibers. Among the various reinforcing natural fibers, sisal fibers are particularly promising for their good mechanical properties, low specific weight and wide availability on the current market. As proven in literature by various authors, the hybridization of biocomposites by synthetical fibers or different natural fibers can lead to an interesting improvement of the mechanical properties or, in turn, of the strength against environmental agents. Consequently, this can lead to a significant enlargement of their practical applications, in particular from quite common non-structural applications (dashboards, fillings, soundproofing, etc.) towards semi-structural (panels, etc.) and structural applications (structural elements of civil construction and/or machine components). Hybridizations with natural fibers or with ecofriendly basalt fibers are the most interesting ones, since they permit the improvement of the biocomposite’s performance without an appreciable increment on environmental impact, as occurs instead for synthetic fiber hybridizations that are also widely proposed in the literature. In order to further increase the mechanical performance and, above all, to reduce the aging effects on high-performance sisal-reinforced biocomposites due to environmental agents, the hybridization of such biocomposites with basalt fibers are studied with tensile, compression and delamination tests performed by varying the exposition to environmental agents. In brief, the experimental analysis has shown that hybridization can lead to further enhancements of mechanical performance (strength and stiffness) that increase with basalt volume fraction and can lead to appreciable reductions in the aging effects on mechanical performance by simple hybridization of the surface laminae. Therefore, such a hybridization can be advantageously used in all practical outdoor applications in which high-performance sisal biocomposites can be exposed to significant environmental agents (temperature, humidity, UV).

Study on the Failure Mechanism of Lower Cambrian Shale under Different Bedding Dips with Thermosolid Coupling

To investigate the damage pattern and acoustic emission pattern of temperature on laminated shales, numerical experiments were carried out using the RFPA2D-Thermal numerical software under the effect of thermosolid coupling. During the tests, temperatures of 30°C, 60°C, and 90°C were controlled, and five sets of shales containing different laminar dips were numerically modeled at each temperature, with dips of 0°, 22.5°, 45°, 67.5°, and 90°. The test results show that (1) the increase in temperature reduced the linear elastic phase of the shale specimens in each group, with a significant reduction in the linear elastic phase of the shale at lamina dips of 22.5° and 45°. (2) The lamination effect decreased slightly as the temperature rose from 30°C to 60°C, and the most significant enhancement of the lamination effect on the shale occurred when the temperature reached 90°C. (3) The shale damage pattern is divided into five types (N, ʌ, v, slanted I-type, and cluttered-type), in which the lamina effect is stronger for high-angle lamina dips, and the lamina surface has a strong dominant effect on the entire shale crack expansion. At a temperature of 90°C, the lamina effect and temperature effect of the shale reached their maximum at the same time, and the thermal and load stresses inside the shale acted together causing the shale to show a complex damage mode. (4) The fractal dimension was used to analyze the damage pattern of the shale. The larger the fractal dimension was, the greater the crack rate of the specimen. The fractal dimension curve was flatter at a temperature of 60°C, while at 90°C, the fractal dimension rose rapidly, indicating the most favorable crack expansion in the shale at a temperature of 90°C.

Effectiveness of Ultrasound-Guided Retrolaminar Block and Erector Spinae Plane Block in Retroperitoneal Laparoscopic Surgery: A Randomized Controlled Trial.

PurposeRetrolaminar block (RLB) and erector spine plane block (ESPB) share a similar block site, but their analgesia principle may differ. This study compared the postoperative analgesic effects of ultrasound-guided RLB and ESPB for retroperitoneal laparoscopic surgery.Patients and MethodsThe study included patients who scheduled for laparoscopic nephrectomy from July 2020 to January 2021. Patients in RLB group received a three-point block at the posterior surface of T8-T10 lamina, and those in ESPB group received at the T9 level. The primary result was the score of visual analogue scale (VAS). Secondary results included information on intraoperative and postoperative analgesia consumption and rescue analgesia usage, skin temperature, serum interleukin (IL)-1β, prostaglandin E2 (PGE2) level and the occurrence of safety events.ResultsThere was no significant difference between the two groups in the postoperative VAS scores at both the rest and cough state (All P>0.05). The skin surface temperature of the affected side and the healthy side in ESPB group was higher than that in the RLB group at the end of the surgery (P=0.002) and after surgery (P=0.016). The RLB group had a higher ephedrine usage than the ESPB group (P=0.027). Compared with the ESPB group, the RLB group had a shorter time to exhaust (P=0.045) and lower serum IL-1β level (P=0.049). Patients in neither group developed severe adverse event.ConclusionUltrasound-guided RLB and ESPB can provide safe and effective postoperative analgesia for retroperitoneal laparoscopic surgery. ESPB has more stable intraoperative hemodynamics, while RLB has more potential research value for patients’ rapid recovery.

Viscous shaping of the compliant cell nucleus.

The cell nucleus is commonly considered to be a stiff organelle that mechanically resists changes in shape, and this resistance is thought to limit the ability of cells to migrate through pores or spread on surfaces. Generation of stresses on the cell nucleus during migration and nuclear response to these stresses is fundamental to cell migration and mechano-transduction. In this Perspective, we discuss our previous experimental and computational evidence that supports a dynamic model, in which the soft nucleus is irreversibly shaped by viscous stresses generated by the motion of cell boundaries and transmitted through the intervening cytoskeletal network. While the nucleus is commonly modeled as a stiff elastic body, we review how nuclear shape changes on the timescale of migration can be explained by simple geometric constraints of constant nuclear volume and constant surface area of the nuclear lamina. Because the lamina surface area is in excess of that of a sphere of the same volume, these constraints permit dynamic transitions between a wide range of shapes during spreading and migration. The excess surface area allows the nuclear shape changes to mirror those of the cell with little mechanical resistance. Thus, the nucleus can be easily shaped by the moving cell boundaries over a wide range of shape changes and only becomes stiff to more extreme deformations that would require the lamina to stretch or the volume to compress. This model explains how nuclei can easily flatten on surfaces during cell spreading or elongate as cells move through pores until the lamina smooths out and becomes tense.

Beilschmiedia danhkyii (Lauraceae), a new species from Vu Quang National Park, Vietnam

The new species Beilschmiedia danhkyii (Lauraceae) is described from Ha Tinh Province, Central Highland of Vietnam. Beilschmiedia danhkyii is characterized by ferruginous hairy terminal buds, branchlets and abaxial surfaces of lamina, subopposite leaves, adaxially impressed midrib and secondary veins, short inflorescence 2–3(–5) cm long, and large ellipsoid fruits 5–8 cm long, by which combination it is cleary distinguished from the other species of Beilschmiedia in the region. Taxonomic description, a table comparing morphological characters of the allied species, and color photo-plate are provided.

Parameters of the gelatinase B activity in the integument epithelium and the lamina propria of the gastric mucosa in experimental acetate ulcer in rats

Objective: to determine the specifi c number and expression intensity of gelatinase B-positive cells in the gastric surface epithelium and lamina propria (cell component) in the area of the ulcerous defect in rats with experimental acetate ulcer of the stomach.Materials and methods: 18 white Wistar rats were divided into three groups: initial (intact), experimental (modeling of an acetate ulcer) and control (falsely operated) in the experiment. Tissues were obtained from the ulceration zone or the presumed ulceration zone (in the initial and control groups) to asses morphological changes and also indicators, characterizing the activity of gelatinase B 7 days after the simulation of the experiment.Results and Discussion. It was revealed some increase in the specifi c number of gelatinase B-positive cells against the background of moderate accumulation of lymphocytes in the integument epithelium of the gastric mucosa. A signifi cant increase in the specifi c number of gelatinase B-positive cells at the maximum intensity of its expression and a moderate accumulation of eff ector cells of tissue alterations was determined in the cellular component of the lamina propria of the gastric mucosa at the same time.

Laryngeal spaces in the newborn larynx

ObjectivesDistributions of laryngeal spaces are important in understanding their functional significance. However, laryngeal spaces in the newborn larynx are enigmatic. MethodsFive normal human newborn larynges were investigated using whole organ serial section technique. ResultsThe chief newborn laryngeal spaces were the preepiglottic space, the paraglottic space and the cricoid area. They consisted of an areolar tissue area composed of brown adipose tissue (immature adipose tissue) and loose elastic and collagen fibers. The newborn preepiglottic space was immature and occupied a small area anterior to the epiglottis. The epiglottis lied on a somewhat horizontal axis and was partially obscured behind the hyoid bone. The hyoid bone overlapped the thyroid cartilage, partially obscuring the superior thyroid notch. The thyroid cartilage was present close to the hyoid bone and the thyrohyoid membrane ran between the superior surface of the thyroid lamina, and not the anteroinferior, but the posteroinferior surface of the hyoid bone. The preepiglottic space was located anterior, lateral and posterolateral to the thyroepiglottic ligament. However, the preepiglottic space was located anterior to the epiglottic cartilage. As seen in adults, the paraglottic space existed medial to the lamina of each bilateral thyroid cartilage. Each bilateral cricoid area was located along not only the superomedial but also the medial portion of the cricoid arch on both sides. ConclusionsAs the child grows, the preepiglottic space, occupying a small area anterior to the epiglottis, likely grows as the larynx descends and acquires the human adult vocal tract. From the functional histoanatomical point of view, the newborn laryngeal spaces appear to be favored for respiration and maintenance of a protective sphincter for the lower airway over phonation.

Electric conductivity and surface potential distributions in carbon fiber reinforced composites with different ply orientations

The electric conductivity and surface potential distributions of carbon fiber laminated panels with different ply orientations have been investigated. We found that the unidirectional (UD) lamina has higher conductivity along the carbon fiber direction than the perpendicular direction, and equipotential contours also show different gradients along the two directions. The cross-ply (CP) and quasi-isotropic (QI) laminates have the mixed effects of the UD lamina electric conductivity and ply orientations, while the surface potential distributions mostly depend on the surface lamina direction. The conductivity along the thickness direction depends on each lamina and inter-laminar bonding. A finite element analysis model was also developed to show the effect of ply orientation on potential distribution. The CP and QI laminates with 0° surface ply have uniform potential distributions and isotropic electricity behaviors. The results could be used to monitor damage locations and design electric composite materials.

"Diminishing returns" for leaves of five age-groups of Phyllostachys edulis culms.

Leaf mass (M) and lamina surface area (A) are important functional traits reported to obey a scaling relationship called "diminishing returns" (i.e., M ∝ Aα>1 ). Previous studies have focused primarily on eudicots and ignored whether the age of leaves affects the numerical value of the scaling exponent (i.e., α). The effect of age was examined using 1623 Phyllostachys edulis leaves from culms differing in age collected in Nanjing, China. The scaling relationships among leaf A, fresh mass (FM), and dry mass (DM) were evaluated using reduced major axis protocols. The bootstrap percentile method was used to test the significance of differences in α-values. Overall, the numerical values of α exceeded 1.0. The scaling relationship between FM and A was statistically more robust than that between DM and A. The scaling exponents of FM vs. A exhibited a "high-low-high-low-high" numerical trend from the oldest to the youngest age-group. FM increased linearly as culm age decreased; the leaf DM per unit area (LMA) exhibited a parabolic trend across the age-groups. "Diminishing returns" is confirmed for all but one age-group of an important monocot species. The relationship between FM and A was statistically more robust than that between DM and A for each age-group. The FM per unit A decreased with increasing age-groups, whereas the middle age-groups had a greater LMA than the oldest and youngest age-groups. These data are the first to show that the age of shoots affects the scaling relationship between leaf mass and area.

Histologic validation of optical coherence tomography-based three-dimensional morphometric measurements of the human optic nerve head: Methodology and preliminary results

PurposeTo compare the three-dimensional (3D) morphology of the deep load-bearing structures of the human optic nerve head (ONH) as revealed in vivo by spectral domain optical coherence tomography (SDOCT) with ex vivo quantitative 3D histology. MethodsSDOCT imaging of the ONH was performed in six eyes from three brain-dead organ donors on life-support equipment awaiting organ procurement (in vivo conditions). Following organ procurement (ex vivo conditions), the eyes were enucleated and underwent a pars plana vitrectomy followed by pressurization to physiologic IOP and immersion fixation. Ex vivo ONH morphology was obtained from high-fidelity episcopic fluorescent 3D reconstruction. Morphologic parameters of the observed ONH canal geometry and peripapillary choroid, as well as the shape, visibility and depth of the lamina cribrosa were compared between ex vivo and in vivo measurements using custom software to align, scale, and manually delineate the different regions of the ONH. ResultsThere was significant correspondence between in vivo and ex vivo measurements of the depth and shape of the lamina cribrosa, along with the size and shape of Bruch's membrane opening (BMO) and anterior scleral canal opening (ASCO). Weaker correspondence was observed for choroidal thickness; as expected, a thinner choroid was seen ex vivo due to loss of blood volume upon enucleation (−79.9%, p < 0.001). In addition, the lamina was shallower (−32.3%, p = 0.0019) and BMO was smaller ex vivo (−3.38%, p = 0.026), suggesting post mortem shrinkage of the fixed tissue. On average, while highly variable, only 31% of the anterior laminar surface was visible in vivo with SDOCT (p < 0.001). ConclusionsMorphologic parameters by SDOCT imaging of the deep ONH showed promising correspondence to histology metrics. Small but significant shrinkage artifact, along with large effects of exsanguination of the choroid, was seen in the ex vivo reconstructions of fixed tissues that may impact the quantification of ex vivo histoarchitecture, and this should be considered when developing models and biomarkers based on ex vivo imaging of fixed tissue. Lack of visibly of most of the lamina surface in SDOCT images is an important limitation to metrics and biomarkers based on in vivo images of the ONH deep tissues.