Base Dimensions Research Articles

Autofluorescence of choroidal melanoma in 51 cases

Aim:To describe the autofluorescence features of choroidal melanoma.Design:Non-comparative case series.Participants:51 consecutive patients.Methods:Standard fundus photography and autofluorescence photography (580 nm excitation, 695 nm barrier filter) were performed on all patients. Clinical...

Myocardial adaptation and efficiency in response to intensive physical training in elite speedskaters

Background Physiological cardiac adaptations to exercise training resulting in the ‘athlete's heart’ are well known. Most of these studies, however, were included either those who exercise to exhaustion, non-elite athletes or those who participate primarily in sports requiring extensive weight training. Studies utilizing conventional and tissue Doppler echocardiographic studies in highly competitive elite athletes whose training includes both aerobic and weight training are limited. Aims and methods 1) To identify baseline cardiovascular structural and physiologic adaptations present in elite athletes who participate in both endurance aerobic and weight training programs and to compare them to similarly aged sedentary controls. The population includes 24 speedskaters participating in the 2006 Olympic Games and 15 sedentary young subjects. 2) To evaluate possible structural and physiologic cardiac changes following short duration, vigorous exercise. We repeated the baseline echocardiographic protocol in the athletes following a 3000 m sprint conducted at race pace. Results Compared to non-athletes, the atrial and left ventricular (LV) volumes at rest were larger in elite athletes. There was enhanced LV diastolic function as manifested by higher early annular (septal and lateral) tissue Doppler velocities ( E′): 12.7 ± 2.3 vs 11.3 ± 1.1 cm/s and 17.4 ± 4.7 vs 14.4 ± 1.2 cm/s, P = 0.025 and 0.020 respectively. Evidence of right ventricular (RV) remodeling included larger basal RV dimensions (38 ± 5 vs 32 ± 4 mm, P = 0.001), attenuated RV systolic function at rest (RV area change 35 ± 13% in athletes vs 47 ± 11% in controls, P = 0.006) and lower RV systolic strain rate (SSR) 1.9 ± 0.5 vs 2.9 ± 1.1/s, P < 0.001). However, there was better right ventricular (RV) diastolic function at rest, E′: 13.5 ± 3.6 vs 11.1 ± 1.5 cm/s ( P = 0.016). Following exercise, the athletes exhibited augmentation of RV systolic function with increased RV fractional area change (increasing to 43 ± 10%, P = 0.007) and SSR (2.5 ± 1.2/s post-exercise, P = 0.038). Conclusion Participation by world-class speedskaters in a vigorous training regimen results in cardiovascular anatomic and physiologic adaptations. These changes, including cardiac chamber dilatation, enhanced ventricular diastolic function and attenuated resting RV systolic function, are likely adaptive and allow for more efficient energy use at rest and a robust response to demands of exercise.

Photodynamic therapy for choroidal metastasis from lung adenocarcinoma

Photodynamic therapy for choroidal metastasis from lung adenocarcinoma

Cation-induced polymorphism in iota-carrageenan

Recent X-ray fiber diffraction patterns from polycrystalline and well-oriented fibers of calcium, rubidium and potassium salt forms of ι-carrageenan correspond to large trigonal unit cells. In contrast to the previously reported sodium and calcium forms that contain three half-staggered double helices, these new unit cells accommodate 4, 16 and 27 double helices, respectively. Interestingly, their basal net dimensions ranging from 23.6 to 68.2 Å can all be generated from the smallest trigonal lattice having cell edge 13.7 Å. The peripheral sulfate groups on the prism shaped ι-carrageenan helix, along with cations and water molecules, are mainly responsible for the association of helices. The existence of several cation-dependent stable crystalline states is compatible with the observed versatility in the physical properties of ι-carrageenan.

Notch–Delta signaling is required for spatial patterning and Müller glia differentiation in the zebrafish retina

Notch–Delta signaling has been implicated in several alternative modes of function in the vertebrate retina. To further investigate these functions, we examined retinas from zebrafish embryos in which bidirectional Notch–Delta signaling was inactivated either by the mind bomb ( mib) mutation, which disrupts E3 ubiquitin ligase activity, or by treatment with γ-secretase inhibitors, which prevent intramembrane proteolysis of Notch and Delta. We found that inactivating Notch–Delta signaling did not prevent differentiation of retinal neurons, but it did disrupt spatial patterning in both the apical–basal and planar dimensions of the retinal epithelium. Retinal neurons differentiated, but their laminar arrangement was disrupted. Photoreceptor differentiation was initiated normally, but its progression was slowed. Although confined to the apical retinal surface as in normal retinas, the planar organization of cone photoreceptors was disrupted: cones of the same spectral subtype were clumped rather than regularly spaced. In contrast to neurons, Müller glia failed to differentiate suggesting an instructive role for Notch–Delta signaling in gliogenesis.

Chemical heterogeneity of a crystal built of nanoscale coherently twinned Yb(2-x)(Fe,Ga)(17+2x) polytypes.

An X-ray study of single crystals extracted from an arc-melted Yb-Fe-Ga alloy showed that the diffraction pattern can be modeled by an intergrown crystal that has three sorts of domains: one hexagonal (1, LuFe(9.5) type) and two rhombohedral (2 a and 2 b, PrFe(7) type), the last two twinned by reticular merohedry. Crystals 1 and 2 are essentially polytypes with maximum degree of order (MDO polytypes), built up of nearly identical slabs that are stacked along [001] in ABAB em leader (1). and ABCABC em leader (2). sequences. Structure refinement was performed by a newly developed program that allowed us to refine several structures on a single data set. We found that the hexagonal and rhombohedral domains differ in chemical composition: while 1 shows a higher rate of Yb substitution by Fe(2) dumbbells, 2 shows partial substitution of Fe by Ga. Our observation of the nanoscale phase segregation is supported by latest finding of nonrandom distribution of stacking faults in a similar 2:17 alloy. An unequal distribution of chemical substitutions in 1 and 2 apparently compensates the inherent mismatch of basal plane dimensions of the individual MDO polytypes and thus constrains their cell parameters within the syntaxy. According to our knowledge this is the first example of two chemically distinct polytypes constituting a single crystal, refined on a single set of diffraction data.

Relation between structural characteristics of talc and its properties as an antisticking agent in the production of tablets.

Antisticking power varies according to the talc considered. Besides its chemical properties, it is necessary to assess its physical properties related to functionality. It is difficult to define the physical properties of talc implicated in its antisticking power. In this work, different talcs were characterised and their performance in reducing sticking in tablet manufacturing was evaluated. The following parameters were studied: apparent density, morphogranulometry, roughness, and the specific surface through the adsorption-desorption of argon. Next, the relationship between the characteristics of talcs and their antisticking power was considered. Talc before and after delamination-which is a way to obtain talcs with different physical characteristics-was compared. Antisticking power appeared to be dependent on the basal dimensions of talc, and on the ratio value of the external specific surface measured by diffractometry to the total specific surface by the BET method. Models to express the effect of textural factors of talc particles on antisticking power were defined.

Heterogeneous nucleation of nylon 6 and PET with selected inorganic compounds

AbstractThe effect of several inorganic compounds in the heterogeneous nucleation of poly(ethylene terephthalate) (PET) and poly(caprolactam) (nylon 6) was studied. Six inorganic chemicals were specifically selected, on the basis of their crystal structure, basal lattice dimensions, and thermal properties, in order to study the effect of temperature in their nucleation capabilities. Considering that temperature is one of the most important variables involved during processing of thermoplastics, the impact of the nucleation ability of the intentionally added heterogeneities was studied in terms of thermal conductivity, thermal expansion, and heat capacity. Six inorganic chemicals, which crystallize in the cubic system, were selected considering that they had variations in one of the thermal properties while the others remained practically constant along the temperature range of interest. The results indicated that, at constant surface area, chemical compounds with lower overall values of thermal expansion and also those with overall higher values of heat capacity promote heterogeneous nucleation; the effect of heat capacity was, however, also found potentially related to a different intrinsic mechanism. The impact of thermal conductivity was not considered significant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 360–368, 2003

Study of talcs as antisticking agents in the production of tablets

Talc is defined as a crystalline structure characteristic of lamellar structures. Antisticking power varies according to the talc considered. Besides chemical properties, it is necessary to assess physical properties related to functionality. It is difficult to define the physical properties of talc implicated in its antisticking power. In this work, we characterized different talcs and then evaluated their performances in reducing sticking in tablet manufacturing. We compared talcs before and after delamination which is a way to obtain talcs with different physical characteristics. Granulometric analysis was carried out by laser diffractometry using a method which made it possible to assess the mean thickness of the lamellar particles. We defined a functionality assay on a single punch press to assess the antisticking power of talcs. The different talcs tested possess a very variable antisticking power towards Avicel PH 102. They present different basal dimensions and particle thickness. The force necessary to detach tablets from the punch surface varies according to the functioning time of the tablet machine, the percentage of talc and the basal dimension of talc.

Crystallographic data on axially compressed Kevlar 49 fibres

Axially compressed Kevlar 49 fibres have been examined by X-ray diffraction methods. The most prominent effect of axial compression is the anisotropic deformation of the unit cell. Whereas thec-axial length, which corresponds to the chain axis, undergoes contraction, the basal plane dimensions manifest enlargement. The deformations increase with the extent of axial compression. The half-widths and the azimuthal spread of reflections also exhibit changes. The compression induced structural changes provide qualitative support to the experimentally observed reduction in tensile strength and modulus.

The Intercalation of Kaolinite by Alkali Halides in the Solid State: A Systematic Study of the Intercalates and their Derivatives

AbstractKaolinite: alkali halide intercalates have been successfully prepared by grinding the salt with kaolinite in the absence of water. Rate of intercalation is shown to correlate negatively with melting point of the salt. The basal dimensions of the intercalates increase with increasing size of the ion. As shown recently for kaolinite: NaCl intercalate, the layered structure survives the dehydroxylation of the kaolinite at 500°–600°C, at which point the excess alkali halide can be removed by rinsing to give an XRD-amorphous material. This amorphous material, of approximate stoichiometry MAlSiO4, reacts at surprisingly low temperatures to give crystalline phases, apparently of the same stoichiometry, with structures closely related to eucryptite (M = Li), carnegieite (M = Na), kalsilite (M = K), and leucite (M = K, Rb, Cs). The relationships between the structures of the reaction products are discussed.

Structural Characterisation of Kaolinite:NaCl Intercalate and its Derivatives

AbstractKaolinite:NaCl intercalates with basal layer dimensions of 0.95 and 1.25 nm have been prepared by direct reaction of saturated aqueous NaCl solution with well-crystallized source clay KGa-1. The intercalates and their thermal decomposition products have been studied by XRD, solid-state 23Na, 27Al, and 29Si MAS NMR, and FTIR. Intercalate yield is enhanced by dry grinding of kaolinite with NaCl prior to intercalation. The layered structure survives dehydroxylation of the kaolinite at 500°–600°C and persists to above 800°C with a resultant tetrahedral aluminosilicate framework. Excess NaCl can be readily removed by rinsing with water, producing an XRD “amorphous” material. Upon heating at 900°C this material converts to a well-crystallized framework aluminosilicate closely related to low-carnegieite, NaAlSiO4, some 350°C below its stability field. Reaction mechanisms are discussed and structural models proposed for each of these novel materials.

Episcleral plaque radiotherapy in the treatment of uveal melanomas

During an 8-year period, 85 patients with uveal melanomas were treated with episcleral plaque radiotherapy (EPRT). The T-stage was: T 1 − 3 (4%), T 2 − 29 (34%) and T 3 − 53 (62%). The mean tumor elevation was 6.1 mm. Radiation dose was prescribed at the tumor apex and at D 5 mm. The mean D 5 mm dose was 150.1 Gy (range 70.5–430 Gy) and the mean dose at the apex was 102.6 Gy (range 29.8–200 Gy). Useful vision ( > 5 200 ) was maintained in 73% of patients. The 5-year actuarial survival was 88%. Metastatic disease developed in 9 (11%) patients, 6 of whom died of their disease. Basal tumor dimensions were important factors predicting metastatic disease, p = 0.002. A decrease in tumor elevation was seen in 82%. There was a much lower incidence of decrease in tumor radial and circumferential dimensions, 47.5 and 46%, respectively, p < 0.001. Treatment complications were common (56%), particularly in patients with large tumors (72%), p = 0.04. The incidence of complications was higher in patients treated prior to 1988 as compared to those who were treated more recently (67 vs 35%, p = 0.010). There were 13 (15%) patients who had enucleation. This included 12 treated before 1986 and 1 patient treated subsequently (46 vs 2%, p < 0.001). In a univariate analysis, tumor height and radiation dose at D5 mm were important factors predicting enucleation, p = 0.004. In a multivariate analysis, however, the most important factor predicting enucleation was treatment administration prior to 1986, p < 0.001). A sharp decrease in the incidence of severe complications, including enucleation, as seen after 1985, is likely due to a major effort in treatment optimization.

An analysis of the forces of fighting of the blackbuck (Antilope cervicapra) and the bighorn sheep (Ovis canadensis) and the mechanical design of the horn of bovids

The costs and benefits of fighting in bovids are high in terms of injury and reproductive success, respectively. The breakage of a horn would curtail reproductive success permanently. Therefore, the horns of bovids should include sufficient material so that they are strong enough to be unlikely to break in fighting but without being too heavy to carry around. The forces developed during fighting were measured in a computerized analysis of film of blackbuck and bighorn sheep. All possible modes of failure were investigated using a mechanical analysis to see how the horns are most likely to fail.The maximum possible force developed during fighting is 3400 N for the bighorn sheep and 456 N for the blackbuck. Bending stress, shear stress, deflection, strain energy and critical crack lengths were calculated for the horns of these two bovids. Horns are most likely to fail in bending as indicated by safety factors. Most of the force is taken in compression due to the curvature of horns. Shear stresses are insignificant and deflections are negligible during the most forceful encounters.The safety factor in bending of the horn of the bighorn sheep is greater (10) than that of the horn of the blackbuck (3.4) because the forces are probably more variable and unpredictable in the fighting of the former.All of the energy of fighting is absorbed by the body musculature because horns store less than 1% of the energy produced in fighting as strain energy when they bend. Cracks and scratches mustbe more than 60% of the transverse basal dimensions of horns in order for there to be catastrophic failure at the maximum stresses developed during fighting.The horns of the blackbuck and the bighorn sheep appear to be minimum weight structures given the variability of the forces acting on them and are unlikely to break in fighting given the forces calculated from the analyses of films.

High-Resolution Imaging of Ordered Mixed-Layer Clays

AbstractHigh-resolution transmission electron microscopy (HRTEM) has been used to examine illite/smectite from the Mancos Shale; rectorite from Garland County, Arkansas; illite from Silver Hill, Montana; Na-smectite from Crook County, Wyoming; corrensite from Packwood, Washington; and diagenetic chlorite from the Tuscaloosa Formation. Thin specimens were prepared by ion milling, ultramicrotome sectioning, and/or grain dispersal on a holey carbon substrate. Some smectite-bearing clays were also examined after intercalation with dodecylamine hydrochloride (DH). Intercalation of smectite with DH proved to be a reliable method for HRTEM imaging of expanded smectite (d (001) = 16 Å) which could then be distinguished from unexpanded illite (d (001) = 10 Å). Lattice fringes of basal spacings of DH-intercalated rectorite and illite/smectite showed a 26-Å periodicity. These data support X-ray powder diffraction (XRD) studies which suggest that these samples are ordered, interstratified varieties of illite and smectite. The ion-thinned, unexpanded corrensite sample showed discrete crystallites containing 10-Å and 14-Å basal spacings corresponding to collapsed smectite and chlorite, respectively. Regions containing disordered layers of chlorite and smectite were also noted. Crystallites containing regular alternations of smectite and chlorite layers were not common. These HRTEM observations of corrensite did not corroborate XRD data. Particle sizes parallel to the c axis ranged widely for each sample studied, and many particles showed basal dimensions equivalent to more than five layers. For all illite, smectite, and illite/ smectite particles examined, crystallite sizes of about 20 Å in the basal dimension were not observed.

Parameterization of stromatoporoid shape

Kershaw, Stephen & Riding, Robert 1978 07 15: Parameterization of stromatoporoid shape. Lethaia, Vol. 11. pp. 233–242. Oslo. ISSN 0024–1164. Stromatoporoid cross-sectional shape can be considered as a product of the interaction of three morphological variables: the relative proportions of basal, vertical and diagonal dimensions. The gross arrangement of internal lamination can be superimposed upon the resulting outlines. These shapes are taken to represent cross sections in any vertical plane through the centre of the coenosteum. This simple parameterization scheme is presented in triangular arrays which include the stromatoporoid morphotypes laminar, domical and bulbous, and varieties of them together with forms not utilized by stromatoporoids. Dendroid and irregular forms are too complex to be readily included in the scheme. Smooth and ragged varieties of laminar and domical forms are distinguished and related to sedimentation on the flanks of the coenosteum. Two types of mutual arrangement of latilaminae within the coenosteum are recognized: enveloping, where they completely overlap previous latilaminae, and non-enveloping, where they do not. Laminar-domical-bulbous forms represent a series generated mainly by reduction of the basal dimension. They commonly exhibit enveloping latilaminae except in ragged varieties and some extended domes. Measurement of defined dimensions in the field allows stromatoporoid morphotypes to be plotted onto the triangular arrays and provides a rapid method of displaying the range of forms present.

Cusp size, sexual dimorphism, and heritability of cusp size in twins.

Overall measures of mandibular molars reflect the combined size contributions of the component cusps and ridges. Until now, the size hierarchy of primary and permanent mandibular molar cusps remained unclear. This paper utilizes the relative plane surface areas (basal area dimensions) of the individual molar cusps, as assays of cusp size to demonstrate cusp size variations within populations, antimere cuspal variations, sexual dimorphism, and, the heritability of cusp size. Duplicate dental casts from 199 pairs of like-sexed twins provide the raw dats. Defined anatomic landmarks on the occlusal surfaces were reduced to X-Y rectangular coordinates prior to the computation of the basal areas dimensions. The results establish a cusp size hierarchy specific for molar type, i.e., five-cusped molars with a distal fovea and distal marginal ridge (5fd), five-cusped molars without a distal fovea and without a distal marginal ridge (5o), and four-cusped molars (4c). Sexual dimorphism in cusp size is apparent in 5fd molar cusped but not in 5o molar cusps. However, males have a significantly higher frequency of 5fd molars. Females have a higher frequency of smaller 5o and 4c molars which have fewer crown components. Moreover, female 5o molars have cusps as large as or larger than 5o male molor cusps. Right-side-left-side differences exist between antimere cusps based on relatively low correlations. The mirroring of molor types occurs infrequently. When observed, most intrapair differences for cusp size, using F-ratios, indicate a low component of hereditary variability.

Cranial base morphology in association with intentional cranial vault deformation.

AbstractComparison of vault and basal dimensions in 86 Amerind crania revealed that artificial deformation is associated with elevation of frontal orbital processes and temporal petrous crests, restriction of normal downward rotation of foramen magnum, and flattening of mid‐saggital cranial base. Circumferentially deformed crania were modified to a greater degree than antero‐posteriorly deformed skulls. While degree of basal deformation was dependent upon type of vault deformation, this study could not demonstrate the existence of a relationship between type of vault deformation and direction of cranial base modification.

A polygon portrayal of coronal and basal arch dimensions in the horizontal plane

In normal dentures there is a range of variation of tooth material, coronal and basal arch width, and basal arch length. There is a range of variation of the interrelationships of these various measurements, which can be plotted on graph paper so that a polygon form represents the normal limits. When similar measurements of malocclusion are plotted on these forms, the deviations from the normal can be observed. These charts or graphs of denture dimensions can be used in conjunction with similar graphs, which compare the cephalometric profile tracing with normal variations of it. Such graphs can be used to eliminate ambiguity in describing an individual dentofacial complex, and to demonstrate what has been accomplished by treatment. Finally, in an individual case analysis, the information obtained from the graphs, combined with other information, aids in planning treatment.

Crystal Structure and Orientation in Thin Films

IN crystal growth, the well-known phenomenon of pseudomorphism extends to all three dimensions. Recently we have found that thin films of aluminium on platinum, of zinc oxide on zinc and of magnesium oxide on magnesium possess abnormal crystal structures. For example, aluminium, normally of face-centred cubic structure (a = 4.05 A.), when deposited as a sufficiently thin layer on face-centred cubic platinum (a = 3.91 A.) acquired a face-centred tetragonal structure with basal axis 3.90 A. and major axis 4.02 A. Thus, in its basal dimensions the aluminium was pseudomorphic with the platinum substrate. A similar effect was observed in the case of a thin film of zinc oxide on zinc (triangular close-packed lattice, a = 2.685 ± 0.002 A.; c = 1.86). In this case, whilst the basal dimensions of the zinc oxide were similar to those of the zinc substrate, the major axis had increased from 5.178 A. (normal zinc oxide) to 6.873 ± 0.002 A. Thus, the volume of the abnormal zinc oxide cell, basally pseudomorphic with normal zinc, was nearly equal to that of the normal zinc oxide cell.