Dense reconstruction of elephant trunk musculature

The elephant trunk operates as a muscular hydrostat1,2 and is actuated by the most complex musculature known in animals.3,4 Because the number of trunk muscles is unclear,5 we performed dense reconstructions of trunk muscle fascicles, elementary muscle units, from microCT scans of an Asian baby elephant trunk. Muscle architecture changes markedly across the trunk. Trunk tip and finger consist of about 8,000 extraordinarily filigree fascicles. The dexterous finger consists exclusively of microscopic radial fascicles pointing to a role of muscle miniaturization in elephant dexterity. Radial fascicles also predominate (at 82% volume) the remainder of the trunk tip, and we wonder if radial muscle fascicles are of particular significance for fine motor control of the dexterous trunk tip. By volume, trunk-shaft muscles6 comprise one-third of the numerous, small radial muscle fascicles; two-thirds of the three subtypes of large longitudinal fascicles (dorsal longitudinals, ventral outer obliques, and ventral inner obliques);7,8,9 and a small fraction of transversal fascicles. Shaft musculature is laterally, but not radially, symmetric. A predominance of dorsal over ventral radial muscles and of ventral over dorsal longitudinal muscles may result in a larger ability of the shaft to extend dorsally than ventrally10 and to bend inward rather than outward. There are around 90,000 trunk muscle fascicles. While primate hand control is based on fine control of contraction by the convergence of many motor neurons on a small set of relatively large muscles, evolution of elephant grasping has led to thousands of microscopic fascicles, which probably outnumber facial motor neurons.

Haemodialysis catheters - a review of design and function

INTRODUCTION

Haemodialysis (HD) catheters are a fundamental form of dialysis access. An appreciation of the principles of catheter design is important for practitioners involved in the insertion and maintenance of haemodialysis access. Although a wide range of styles and brands are available on the market, comparative clinical trials are lacking.

AREAS COVERED

This concise review outlines common dialysis catheter characteristics and summarises their practical relevance. Materials and surface coatings, tip geometry, side holes, and lumen cross-sectional shape are discussed.

EXPERT OPINION

HD catheter choice should be at the operator's discretion based on their best clinical judgement and experience. While device selection should be informed theoretic design principles, more important is a concentration on thoughtful catheter insertion and maintenance practices.

A retrospective study of factors contributing to anchorage loss in upper premolar extraction cases

Background

Anchorage control is one of the components in the treatment of extraction cases. However, what determines more or less anchorage loss is still an unanswered question. Aim: The purpose of this study was to investigate the most important factors contributing to the anchorage loss of maxillary first molars in premolar extraction cases.

Materials and Methods

The study included 726 upper premolar extraction cases, including 214 male patients and 512 female patients, and the mean age was 14.4 ± 4.5 years old (range: 9-45). Factors including physiological characteristics, treatment mechanics, and cephalometric variables were collected and their influences on the angulation changes of maxillary first molars were analyzed.

Results

The mean angulation change of maxillary first molar after treatment was 2.81°(mesial tipping). The change of UM/PP showed a statistically significant difference in different sex (male 3.84° ± 5.26° vs female 2.38° ± 5.10°), age (adult -0.05° ± 4.73° vs teenager 3.46° ± 5.07°), and molar relationship (Class II 3.28° ± 5.15° vs Class I 2.36° ± 5.19°). There are six variables accounted in the regression analysis (R = 0.608, R² = 37.0%). Among them, the pre-treatment molar tipping (Standardized Coefficients: -0.65) and the pre-treatment incisor/molar height ratio (Standardized Coefficients: -0.27) were the most important factors influencing anchorage loss during treatment.

Conclusion

Compared with treatment-related factors, the patient's physiological characteristics play a more important role in anchorage loss. The pre-treatment angulation of the maxillary first molar is the most influential factor in changes to maxillary molar angulation, which are often predisposing anchorage loss.

Aortic cannula tip dislodgement: A rare complication

Cardiac surgery involves use of cardiopulmonary bypass which usually requires a circulatory circuit containing numerous cannulae and tubings draining from major vessels (like superior and inferior vena cavae) and returning it back to the systemic circulation (via the aorta, femoral artery, axillary artery etc). Establishment of this circuit not only requires good surgical skills for technical procedures but also requires stringent vigilance and awareness about the working of these disposable items. Surgeons concentrating in the technical aspect might miss out on the minor manufacturing defects in these disposable items and anesthesiologist as well as perfusionist can contribute in this aspect by including systematic precheck of these items to avoid complications in future. In this case report, we would like to discuss a simple case of mitral valve replacement where during aortic decannulation the metallic tip got dislodged and thus got migrated to the abdominal aorta. This is a rare complication which none of us were expecting. By prechecking the various components of the cardiopulmonary bypass circuit, this complication was expected to be avoided.

Micro-Cantilever Displacement Detection Based in Optical Fiber Tip

This work demonstrates the potential of combining a microsphere with a tip for the functionality of the contact sensor. This sensor consists of a tip aligned with the fiber core and a microsphere, which appears during tip formation. This new structure was produced using the electric arc machine. The sensor operation consists of the variation of the tip curvature, which causes a variation of the optical paths and, consequently, a change in the output signal. The study of this micro-cantilever consisted of an exploration of the contact mode. In addition, the sensor was characterized by temperature, which shows very low sensitivity and vibration. This last characterization was performed with two configurations parallel and perpendicular to the oscillating surface. The perpendicular case showed higher sensitivity and has an operating band of 0 Hz to 20 kHz. In this configuration, for frequencies up to 2 Hz, the intensity varies linearly with the frequencies and with a sensitivity of 0.032 ± 0.001 (Hz^-1). For the parallel case, the operating band was from 1.5 kHz to 7 kHz.

Report on the breakage of the tip of a radial endobronchial ultrasonic probe sheath during bronchoscopy

A lesion in a 73-year-old woman that was suspected to be right lung cancer was biopsied under ultrasound-guided bronchoscopy with a guide sheath. The procedure was completed without a noticeable problem, but after 3 days, it was found that the tip of the ultrasonic probe sheath was broken and that the broken fragment was missing. Based on the concern that the fragment had been left in the lung, the patient was examined by computed tomography scan 4 days after the biopsy, and bronchoscopy was repeated 38 days after the biopsy, but no fragment was detected. These procedures and an investigation by the Olympus Corporation led to the conclusion that the fragment was not in the lung, and it was not found in a subsequent surgical specimen. Breakage of devices may occur at any time regardless of progression of fatigue (wear) with increased use, and thorough device management before, during, and after use is important.

Ulnar Thumb Pulp Reconstruction Using the Anterograde Homodigital Neurovascular Island Flap

The thumb ulnar pulp is a critical component of key pinch and precision manipulation. Injuries to this area should be reconstructed with robust, sensate tissue that restores bulk and contour. The existing reconstructive options, however, have substantial risks and drawbacks. We describe an anterograde homodigital neurovascular island flap that provides both sensate and durable coverage of the ulnar thumb pulp. The flap uses innervated glabrous tissue, limits donor site morbidity to the thumb and first web space, and does not require microvascular anastomoses or nerve coaptation. The flap has been previously described for nonthumb fingertip injuries, but it has not been applied to the thumb. We discuss several important technical modifications that are essential to raising and insetting this flap in the thumb, review potential pitfalls, and highlight key steps to ensuring judicious intraoperative decision making and success.

Tips and nodes are complementary not competing approaches to the calibration of molecular clocks

Molecular clock methodology provides the best means of establishing evolutionary timescales, the accuracy and precision of which remain reliant on calibration, traditionally based on fossil constraints on clade (node) ages. Tip calibration has been developed to obviate undesirable aspects of node calibration, including the need for maximum age constraints that are invariably very difficult to justify. Instead, tip calibration incorporates fossil species as dated tips alongside living relatives, potentially improving the accuracy and precision of divergence time estimates. We demonstrate that tip calibration yields node calibrations that violate fossil evidence, contributing to unjustifiably young and ancient age estimates, less precise and (presumably) accurate than conventional node calibration. However, we go on to show that node and tip calibrations are complementary, producing meaningful age estimates, with node minima enforcing realistic ages and fossil tips interacting with node calibrations to objectively define maximum age constraints on clade ages. Together, tip and node calibrations may yield evolutionary timescales that are better justified, more precise and accurate than either calibration strategy can achieve alone.

NMR identification of the binding surfaces involved in the Salmonella and Shigella Type III secretion tip-translocon protein-protein interactions

The type III secretion system (T3SS) is essential for the pathogenesis of many bacteria including Salmonella and Shigella, which together are responsible for millions of deaths worldwide each year. The structural component of the T3SS consists of the needle apparatus, which is assembled in part by the protein-protein interaction between the tip and the translocon. The atomic detail of the interaction between the tip and the translocon proteins is currently unknown. Here, we used NMR methods to identify that the N-terminal domain of the Salmonella SipB translocon protein interacts with the SipD tip protein at a surface at the distal region of the tip formed by the mixed α/β domain and a portion of its coiled-coil domain. Likewise, the Shigella IpaB translocon protein and the IpaD tip protein interact with each other using similar surfaces identified for the Salmonella homologs. Furthermore, removal of the extreme N-terminal residues of the translocon protein, previously thought to be important for the interaction, had little change on the binding surface. Finally, mutations at the binding surface of SipD reduced invasion of Salmonella into human intestinal epithelial cells. Together, these results reveal the binding surfaces involved in the tip-translocon protein-protein interaction and advance our understanding of the assembly of the T3SS needle apparatus. Proteins 2016; 84:1097-1107. © 2016 Wiley Periodicals, Inc.

A normative study to evaluate inclination and angulation of teeth in North Indian population and comparision of expression of torque in preadjusted appliances

Aim:

The aim of this study was to evaluate angulation and inclination of teeth from the study models of individuals with normal occlusion and evaluation of actual expression of torque expressed by three different bracket systems.

Materials and Methods:

In this study, the inclination and angulation were measured on 30 study models of North Indian individuals. A self-developed instrument (torque angle gauge) was used for the measurement. Fifteen study models were duplicated for the evaluation of torque expression in the bracket of three different manufacturers with different shape and size of bases.

Results:

The results give the mean, minimum and maximum, standard deviation of the normative data individually for each tooth. A significant correlation was noted in the angulation of maxillary canine and first premolar, and between premolars; and between mandibular central incisor with lateral incisor and canine, and between premolars.

Conclusions:

There was a highly significant correlation of teeth angulation and inclination in the maxillary and mandibular arch. Though the error in expression of torque was not significant, but it showed a large range, indicating the need to vary the position of brackets in different bracket systems for achieving optimum torque.

Canal-centering ability: An endodontic challenge

During instrumentation of the root canal, it is important to develop a continuously tapered form and to maintain the original shape and position of the apical foramen. However, the presence of curvatures may cause difficulty in root canal instrumentation. The ability to keep the instruments centered is essential to provide a correct enlargement, without excessive weakening of the root structure. Several studies have shown that Ni-Ti instruments remain significantly more centered and demonstrated less canal transportation than stainless steel files. Considerable research has been undertaken to understand the several factors related to an instrument's canal-centering ability. In this article, we have discussed the influence of various parameters such as alloys used in the manufacture of instruments, instrument cross-section, taper, and have given tips on canal-centering ability.