Straight Fashion Research Articles

Anatomy of the female urogenital system of the West African Giraffe (Giraffa camelopardalis peralta)

The knowledge of the anatomy of organs of the urogenital system is vital in understanding aetiologies of anomalies. To this end, morphology and morphometry of the organs of reproduction and urine formation, from autopsies of two adult non-gravid West African giraffes (Giraffa camelopardalis peralta) at the Faculty of Veterinary Medicine, University of Ilorin, Ilorin, Nigeria were studied. In situ, two encapsulated kidneys were found to be retroperitoneal and asymmetrically pressed against the dorsal abdominal wall on each side of the aorta and caudal vena cava by perirenal fats, blood vessels and other abdominal viscera. The right kidney was more cranial than the left. Cross- sectionally, the kidneys depicted an outer dark-brown cortex and an inner light pink medulla. The cranial pole of the kidney was characterised of poorly developed renal pyramids whose papilla coalesced into a renal crest. Conversely, there were distinct renal pyramids in the caudal pole, each separated by minor calyx that collected into a major calyx leading to the renal pelvis. A funnel-shaped renal pelvis continued outside a hilus as a tubular structure, the ureter which passed caudally in the retroperitoneal space along the dorsal abdominal wall to reach the pelvic cavity, and ended at the dorsolateral surface of the neck of the urinary bladder, ventral to the uterus. The neck of the urinary bladder was continuous with the urethra. Paired ellipsoidal shaped, laterally flattened ovaries were located close to the middle of the lateral side of the pelvic inlet. Sagittally, the ovaries revealed centralized medulla and peripheral cortices. Paired flexuous oviducts, comprising a cranial funnel-shaped infundibulum, middle ampulla and caudal isthmus, which terminated at the cranial part of the uterine horn emanated from the ovaries. The uterus was located entirely in the pelvic cavity, had a cranial paired uterine horn that fused caudally to form the middle short uterine body. Uterine horns and body presented three rows of erect, leaf-like papillae (caruncles) arranged in straight fashion on the endometrium. The uterine cervix was a short, firm, thick muscular tube. Its lumen was narrowed by three rings and thick mucus plug. The vagina was long and wide located between the dorsal rectum and ventral bladder in situ. Its mucosa presented shallow longitudinal folds which were less prominent at its middle. The vulva presented a short caudal tubular continuation of the vagina as the vestibule; it was horizontally oriented and demarcated from the vagina by a shallow transverse groove. The external urethral orifice opened on its cranio-ventral surface forming a midline longitudinal groove that extended to the clitoris. The vulva also presented two labia that met at the dorsal and ventral commissures. It was concluded from the study that female urogenital anatomy of the giraffe shows semblance with those of other ruminants with some variations.

Effects of lateral osteotomy on surgically assisted rapid maxillary expansion

This study aimed to assess the potential effects of two different osteotomy designs of the maxillary lateral wall on dental and skeletal changes after surgically assisted rapid maxillary expansion (SARME). Thirty adult patients were divided into two groups according to the lateral osteotomy design: group 1 (n=16) underwent lateral osteotomy performed in a horizontal straight fashion, and group 2 (n=14) underwent lateral osteotomy performed in parallel to the occlusal plane with a step at the zygomatic buttress. Cone beam computed tomography scans were obtained preoperatively (T1), immediately after expansion (T2), and 6 months after expansion (T3). Mixed analysis of variance (ANOVA) was used for the statistical analysis. The results showed no significant interaction effect between groups and time points. Therefore, maxillary expansion was effective in both groups. Statistically significant increases in all dental and skeletal measurements were observed immediately after expansion (P<0.001). Relapse of the nasal floor width, tipping of the supporting teeth, and an increase in root distance in molars occurred at T3 (P<0.05). In summary, the maxillary lateral osteotomy design did not influence the results of SARME, which occurred mainly through the inclination of maxillary segments.

ChemInform Abstract: Metal‐Based Molecular Chains: Design by Coordination Chemistry

AbstractReview: 96 refs.

METAL-BASED MOLECULAR CHAINS: DESIGN BY COORDINATION CHEMISTRY

Molecular extended metal atom chains (EMACs) or “molecular chains” are discrete molecules exhibiting arrays of closely spaced metals in a nearly straight fashion. Such species are gaining momentum as possible crucial components of molecular functional devices. The synthetic strategies for the preparation of such species have diversified over the years. The existing strategies rely either on the formation of “unsupported” metal-metal bonds or depend entirely on the ability of specifically designed ligands to promote the assembly of metals in desired topologies. In this review, a summary of the methods employed for the preparation of molecular EMACs is presented, and several important examples are described.

Metallation of bipyridine derivatives substituted at meta position by alkyl chains: effects on the 2D structures

Bipyridine derivatives (bpys) substituted by alkyl chains at meta position were observed by scanning tunnelling microscopy at a highly oriented pyrolytic graphite–1-phenyloctane interface. In those molecules, the alkyl chains were interdigitated, and the π-conjugated bipyridine core parts were aligned side by side. Metal coordination should induce 2D structural transformations due to the alteration of intermolecular interactions. The bpy platinum complexes were aligned in a straight fashion, in which the alkyl chains were interdigitated. The molecular arrangements were quite different from those of free bpy. In contrast, there was no structural change in the case of palladium complexes, suggesting the decoordination of the ligand from the metal. The equilibrium of metallation/demetallation affected the 2D structure, and should be taken into account for the nanoarchitecture design on the basis of the intermolecular interactions.

One-dimensional supramolecular surface structures: 1,4-diisocyanobenzene on Au(111) surfaces

One-dimensional supramolecular structures formed by adsorbing low coverages of 1,4-diisocyanobenzene on Au(111) at room temperature are obtained and imaged by scanning tunneling microscopy (STM) under ultrahigh vacuum (UHV) conditions. The structures originate from step edges or surface defects and arrange predominantly in a straight fashion on the substrate terraces along the <110> directions. They are proposed to consist of alternating units of 1,4-diisocyanobenzene molecules and gold atoms with a unit cell in registry with the substrate corresponding to four times the lattice interatomic distance. Their long 1-D chains and high thermal stability offer the potential to use them as conductors in nanoelectronic applications.

The Mechanism of Filament Rotation in Gliding Assays with Non-Processive Myosin Motors

We present a model study of gliding assays in which actin filaments are moved by non-processive myosin motors. We show that even if the power stroke of the motor protein has no lateral asymmetry, the filaments will move in a helical, rather than straight fashion. Notably, the handedness of this twirling motion is the opposite from that of the actin filaments. It stems from the fact that the gliding actin filament has “target zones” where its subunits are oriented towards the surface and are therefore more accessible for myosin heads. Because each myosin head has a higher binding probability before it reaches the center of the target zone than afterwards, this results in a left-handed helical motion of the actin filament. We present a stochastic simulation and an approximative analytical solution to study this effect. We show that the pitch of the helix depends on the filament velocity, which in turn depends on the ATP concentration. It reaches about 400nm for slow gliding and increases with higher speeds. These values are in good agreement with recent experiments.

Effect of nanoplatelet dispersion on mechanical behavior of polymer nanocomposites

AbstractBy manipulating processing conditions, three levels of exfoliation of synthetic α‐zirconium phosphate (α‐ZrP) nanoplatelets in epoxy matrices have been achieved. Transmission electron microscopy and wide angle X‐ray diffraction were utilized to confirm the three different levels of exfoliation of nanoplatelets in epoxy/α‐ZrP nanocomposites. As expected, it was found that modulus and strength of the nanocomposite are affected by how well the nanoplatelets disperse. It was also found that the operative fracture mechanisms depend strongly on the state of the nanoplatelets dispersion. The crack deflection mechanism, which leads to a tortuous path crack growth, was only observed for poorly dispersed nanocomposites. Delamination of intercalated nanoplatelets and crack deflection were observed in a moderately dispersed system. In the case of fully exfoliated system, the crack only propagated in a straight fashion, which indicates that the fully exfoliated individual nanoplatelet can not affect the propagation of crack at all. The implication of the present findings for structural applications of polymer nanocomposites is discussed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1459–1469, 2007

Aglaothamnion okiense sp. nov. (Ceramiaceae, Rhodophyta) from the Sea of Japan

A new minute species of Aglaothamnion is reported from the Sea of Japan. Thalli are 2-5 mm in height, tufted with one to several main axes which become distally indistinct, robust, light pink, commonly ecorticate. Vegetative cells are uninucleate. The first order lateral branches are radially alternate in arrangement. Basal rhizoids produced secondary upright axes. Plants are dioecious. The carpogonial branch cells are arranged in zigzag or straight fashion. Gonimolobes are irregularly lobed and narrow to pointed. Spermatangial mother cell filaments are parallel to the adaxial surface of the male fertile segment, and each mother cell produces 1-4 uninucleate spermatangia (...)

An Analysis of Paths of Brittle Cracks Propagating along Butt Welded Joints

In order to preserve the structural integrity against brittle fracture, structural materials should be selected based on the proper evaluations of the fracture toughness of materials and of the near tip field parameters of a crack by an appropriate stress analysis. In welded structures there exist some difficulties in achieving the procedure. The precise evaluation of the fracture toughness of materials is not a simple task, if a welding process induces the spatially distributed inhomogeneous material degradation such as the locally restrained decrease of the fracture toughness in the heat affected zone. Considering a brittle crack initiated and propagating along a welded joint, it sometimes exhibits sharply curved paths and penetrates into the base material, while in other cases it propagates in a straight fashion along the welded joint. It is clear from these observations that the prediction of brittle crack paths is essential for the evaluation of fracture toughness of welded structures.In the present paper a mathematical model is proposed for the crack path prediction, in which the combined effects of applied stresses, welding residual stresses, and material degradation in the so-called heat affected zone are taken into account. In the present model a homogeneous fracture toughness is assumed in both the base and weld materials, where the crack path is predicted by the local symmetry criterion (KII =0) based on the first order perturbation solution of a slightly kinked and curved crack. When a curved crack propagating in a weld material intersects the heat affected zone which is modelled as a line degradation zone, a quastion arises as to whether the crack extends along the heat affected zone, or whether it penetrates into the base material. Since the local symmetry criterion does not work at this point, the crack growth direction is predicted by the minimum principle of the total potential energy. The relevant energy calculations can easily be performed by using the second order perturbation solution of a kinked crack.Numerical results show that if brittle fracture occurs under a relatively low applied stress in comparison with the longitudinal welding residual stress, and if the average material degradation along the heat affected zone is small, crack paths tend to deviate from the welded joint. This is the case actually observed for brittle fracture of welded plates made of mild steel, where cracks extend in the base material. It is also shown that cracks tend to propagate along the heat affected zone with increasing the applied stress and materials degradation levels, which may possibly simulate certain brittle fracture of welded plates made of high tensile steel.