Cylindrical Organ Research Articles

Overview Aspects of Anatomy and Histology of the Trachea, Pharynx, Larynx, and Esophagus: A Narrative Literature Review

This literature review aimed to describe the anatomical and histological aspects of the trachea, pharynx, larynx, and esophagus. The trachea is a tube-shaped respiratory tract consisting of cartilage and muscle and lined by a pseudostratified columnar ciliated epithelium. The pharynx is a funnel-shaped fibromuscular pouch that is large at the top and narrow at the bottom. This pouch starts at the base of the skull and continues through the esophagus to the level of the sixth cervical vertebra. The laryngopharynx is bordered superiorly by the upper edge of the epiglottis, anteriorly by the larynx, inferiorly by the esophagus, and posteriorly by the cervical vertebrae. The esophagus is a hollow cylindrical organ about 25 cm long and 2 cm in diameter, which extends from the hypopharynx to the cardia of the stomach. The esophagus lies posterior to the heart and trachea, anterior to the vertebrae, and pierces the diaphragmatic hiatus just anterior to the aorta. In conclusion, a thorough understanding of neck anatomy helps establish the diagnosis and management of patients in clinical situations.

Ecology and Evolution of Phenotypic Plasticity in the Penis and Cirri of Barnacles.

Most barnacles are sessile, simultaneous hermaphrodites that reproduce by copulation. This is achieved through the extension of a muscular penis, famous for being the proportionally largest in the animal kingdom. The penis is a long cylindrical or conical organ, composed of a series of folded rings, allowing it to stretch to great lengths. The penises are covered with chemosensory setae allowing them to seek out receptive neighbors. For many species, the condition of the penis changes seasonally. In the most extreme circumstances, it degenerates and is shed during the first post-mating molt and is re-grown for the next mating season. Barnacle penises have been shown to exhibit phenotypic plasticity in response to many different challenges. When exposed to heavy waves, diameter is increased by thickening both the cuticle and muscles. When mates are far, length increases by adding ringed annulations. Experiments have shown that these plastic traits are modular, capable of changing independently from each other and that they improve mating ability. Alternate strategies to increase reproductive ability by barnacles include the production of dwarf and complemental males, sperm casting and sperm leakage, and aerial copulation. All of these mating strategies may have important implications for the study of reproductive biology, life history, and sex allocation theory.

A comparative study of PCA, SIMCA and Cole model for classification of bioimpedance spectroscopy measurements

Due to safety and low cost of bioimpedance spectroscopy (BIS), classification of BIS can be potentially a preferred way of detecting changes in living tissues. However, for longitudinal datasets linear classifiers fail to classify conventional Cole parameters extracted from BIS measurements because of their high variability. In some applications, linear classification based on Principal Component Analysis (PCA) has shown more accurate results. Yet, these methods have not been established for BIS classification, since PCA features have neither been investigated in combination with other classifiers nor have been compared to conventional Cole features in benchmark classification tasks.In this work, PCA and Cole features are compared in three synthesized benchmark classification tasks which are expected to be detected by BIS. These three tasks are classification of before and after geometry change, relative composition change and blood perfusion in a cylindrical organ. Our results show that in all tasks the features extracted by PCA are more discriminant than Cole parameters. Moreover, a pilot study was done on a longitudinal arm BIS dataset including eight subjects and three arm positions. The goal of the study was to compare different methods in arm position classification which includes all three synthesized changes mentioned above. Our comparative study on various classification methods shows that the best classification accuracy is obtained when PCA features are classified by a K-Nearest Neighbors (KNN) classifier. The results of this work suggest that PCA+KNN is a promising method to be considered for classification of BIS datasets that deal with subject and time variability.

In vitro large diameter bowel anastomosis using a temperature controlled laser tissue soldering system and albumin stent

In today's age of advancing surgical technology, there is a need for better and simpler methods of tissue bonding. The use of lasers for tissue welding or soldering is one of these sutureless methods. In 30 years of laser tissue bonding (LTB) research, published reports of cylindrical organ anastomosis were limited to small diameters. The tension resisted by the anastomosis, which is caused by the intraluminal pressure, is also proportional to the organ diameter. Therefore the anastomosis of large diameter organs requires significantly stronger mechanical strength. The aim of this study is to demonstrate such an anastomosis. In vitro anastomosis of porcine small bowel was performed by either LTB or sutures. Anastomosis in the laser group (number of samples, n = 15) included two main stages of soldering. The bowel edges were approximated over a solid albumin stent and heated with a temperature controlled GaAs laser system to 75 degrees C. This was followed by spreading liquid albumin on the anastomotic line and heating by the same system again to 75 degrees C. The control group (n = 5) was sutured anastomosis. All anastomoses were assessed by burst pressure measurement. The burst pressure of the laser group attained 170+/-40 mmHg which was significantly higher than that of the sutured group 83+/-37 mmHg (P < 0.001). This report describes the in vitro LTB anastomosis of a large diameter cylindrical organ. The immediate bond strength, as estimated by burst pressure measurements, was double compared to sutured anastomosis.

Evaluation of optimization strategies and the effect of initial conditions on IMAT optimization using a leaf position optimization algorithm

Intensity-modulated arc therapy (IMAT) is a rotational variant of intensity-modulated radiation therapy (IMRT) that can be implemented with or without angular dose rate variation. The purpose of this study is to assess optimization strategies and initial conditions using a leaf position optimization (LPO) algorithm altered for variable dose rate IMAT. A concave planning target volume (PTV) with a central cylindrical organ at risk (OAR) was used in this study. The initial IMAT arcs were approximated by multiple static beams at 5° angular increments where multi-leaf collimator (MLC) leaf positions were determined from the beam's eye view to irradiate the PTV but avoid the OAR. For the optimization strategy, two arcs with arc ranges of 280° and 150° were employed and plans were created using LPO alone, variable dose rate optimization (VDRO) alone, simultaneous LPO and VDRO and sequential combinations of these strategies. To assess the MLC initialization effect, three single 360° arc plans with different initial MLC configurations were generated using the simultaneous LPO and VDRO. The effect of changing optimization degrees of freedom was investigated by employing 3°, 5° and 10° angular sampling intervals for the two 280°, two 150° and single arc plans using LPO and VDRO. The objective function value, a conformity index, a dose homogeneity index, mean dose to OAR and normal tissues were computed and used to evaluate the treatment plans. This study shows that the best optimization strategy for a concave target is to use simultaneous MLC LPO and VDRO. We found that the optimization result is sensitive to the choice of initial MLC aperture shapes suggesting that an LPO-based IMAT plan may not be able to overcome local minima for this geometry. In conclusion, simultaneous MLC leaf position and VDRO are needed with the most appropriate initial conditions (MLC positions, arc ranges and number of arcs) for IMAT.

Sci-Fri PM: Planning-03: Fundamental understanding of the inter-relation of arc range, angular dose rate and MLC leaf position optimization of Intensity Modulated Arc Therapy for a concave target.

Intensity Modulated Arc Therapy (IMAT) is a rotational variant of Intensity Modulated Radiation Therapy (IMRT) that can be implemented with or without angular dose rate optimization. The purpose of this study is to determine the inter-relationship among arc range, Multi-Leaf Collimator (MLC) leaf positions and angular dose rate optimizations for IMAT delivery of a concave target. A concave planning target volume (PTV) with central cylindrical organ at risk (OAR) was used in dissecting the inter-relationships. Plans with full and limited arc range were generated using leaf position optimization (LPO) alone, angular dose rate optimization (ADRO) alone or LPO followed by ADRO. Two initial IMAT arcs were conformal avoidance arcs created with 5° angular increments where MLC leaf positions were determined from the beams eye view to irradiate the PTV but avoid the OAR. The objective function value (evaluating dose to PTV and OAR), a conformity index, dose homogeneity index, mean dose to OAR and normal tissues were computed and used to evaluate the treatment plans. Dose rate variations and MLC leaf movements as a function of gantry angle were examined in this approach. The results demonstrate that LPO followed by ADRO provided the lowest objective function values, best conformity and dose homogeneity indices, and third in mean dose to OAR and normal tissues for the complete arc range. Future work will address different strategies for simultaneously optimizing both the MLC leaf positions and the variable angular dose rate for IMAT delivery and compare single and multiple arc plans.

Technical Note: Dose‐volume histogram analysis in radiotherapy using the Gaussian error function

A mathematical model based on the Gaussian error and complementary error functions was proposed to describe the cumulative dose-volume histogram (cDVH) for a region of interest in a radiotherapy plan. Parameters in the model (a, b, c) are related to different characteristics of the shape of a cDVH curve such as the maximum relative volume, slope and position of a curve drop off, respectively. A prostate phantom model containing a prostate, the seminal vesicle, bladder and rectum with cylindrical organ geometries was used to demonstrate the effect of interfraction prostate motion on the cDVH based on this error function model. The prostate phantom model was planned using a five-beam intensity modulated radiotherapy (IMRT), and a four-field box (4FB), technique with the clinical target volume (CTV) shifted in different directions from the center. In the case of the CTV moving out of the planning target volume (PTV), that is, the margin between the CTV and PTV is underestimated, parameter c (related to position of curve drop off) in the 4FB plan and parameters b (related to the slope of curve) and c in the IMRT plan vary significantly with CTV displacement. This shows that variation of the cDVH is present in the 4FB plan and such variation is more serious in the IMRT plan. These variations of cDVHs for 4FB and IMRT are due to the different dose gradients at the CTV edges in the anterior and posterior directions for the 4FB and IMRT plan. It is believed that a mathematical representation of the dose-volume relationship provides another viewpoint from which to illustrate problems with radiotherapy delivery such as internal organ motion that affect the dose distribution in a treatment plan.

The oesophageal zero-stress state and mucosal folding from a GIOME perspective.

The oesophagus is a cylindrical organ with a collapsed lumen and mucosal folds. The mucosal folding may serve to advance the function of the oesophagus, i.e. the folds have a major influence on the flow of air and bolus through the oesophagus. Experimental studies have demonstrated oesophageal mucosal folds in the no-load state. This indicates that mucosal buckling must be considered in the analysis of the mechanical reference state since the material stiffness drops dramatically after tissue collapse. Most previous work on the oesophageal zero-stress state and mucosal folding has been experimental. However, numerical analysis offers a promising alternative approach, with the additional ability to predict the mucosal buckling behaviour and to calculate the regional stress and strain in complex structures. A numerical model used for describing the mechanical behaviour of the mucosal-folded, three-layered, two-dimensional oesophageal model is reviewed. GIOME models can be used in the future to predict the tissue function physiologically and pathologically.

The role of Ca2+ influx and intracellular Ca2+ release in the muscarinic‐mediated contraction of mammalian urinary bladder smooth muscle

OBJECTIVE To study the involvement of extracellular Ca2+ and the properties of the intracellular Ca2+ ([Ca2+]i) stores on the carbachol-induced contraction of mammalian urinary bladder smooth muscle strips under polarized and depolarized conditions. Strips of bladder were suspended between platinum ring electrodes in a cylindrical organ bath (0.2 mL) and continuously superfused with Krebs' solution at 1 mL/min. The effect of nifedipine, cyclopiazonic acid (CPA), thapsigargin, procaine, ryanodine and caffeine before and during a 10-s application of 100 microm carbachol under polarized conditions were studied. The effect of these drugs was also assessed under depolarized conditions using a protocol that allowed a more detailed assessment of the role of [Ca2+]i stores, consisting of emptying the stores by exposure to Ca2+-free solution, rapidly refilling them by a 10-s application of 81.5 mm Ca2+ (priming), returning to the Ca2+-free solution for 3 min and then applying 100 microm carbachol (10 s) in Ca2+-free solution (store release). Under polarized conditions, nifedipine and Ca2+ removal almost completely inhibited the carbachol-induced contractions. CPA increased the amplitude and duration of both carbachol- and electrical field stimulation-induced contractions. Although ryanodine had no inhibitory effect, caffeine and procaine significantly inhibited the carbachol-induced contraction. Under depolarized conditions nifedipine blocked both priming and store release contractions. CPA, thapsigargin, procaine and ryanodine significantly increased the priming and inhibited the store release contractions. However, caffeine virtually abolished both priming and store release contractions. These results suggest that in guinea-pig urinary bladder smooth muscle the Ca2+ necessary for contraction enters the cell through voltage-dependent dihydropyridine-sensitive Ca2+ channels and is pumped into an intracellular store that is released by carbachol. Under polarized conditions, the blockade of sarco-endoplasmic reticulum calcium ATP-ase (SERCA) with CPA increases [Ca2+]i and carbachol-induced contractions. The effects of caffeine and procaine suggest that store release involves ryanodine receptors and calcium-induced calcium release. Under depolarized conditions, Ca2+ entry is blocked by nifedipine and the stores diminish. Stored Ca2+ is also greatly reduced by the blockade of SERCA with either CPA or thapsigargin. Procaine, ryanodine and caffeine blocked the store release contractions, suggesting that this involves ryanodine receptors and calcium-induced calcium release.

Experimental investigations of wall influences on woodwind instrument sound

Influences of wall vibrations and thermal/viscous dissipation at the walls on loudness and sound quality of some woodwind instruments (clarinets, recorders, organ flue pipes) were investigated experimentally. Instruments with various wall thicknesses and wall porosities were studied. Wall vibrations were not found to influence the air oscillations except for a very thin-walled cylindrical organ flue pipe. For this pipe, level increases of 3 dB and perceptible sound quality changes were observed when the upper part of the pipe was clamped. From input impedance measurements of instruments geometrically identical, but varying in wall porosity, it was found that the quality factor of the resonances could vary by a factor of 2. The sound level produced by blowing these instruments appeared (at a certain blowing pressure) to be proportional to the real part of the input impedance. The pressure level at which a recorder overblows appeared to increase with the input impedance. Besides wall damping, variations in the bore, which determine the exact positioning of eigenfrequencies, were also found to affect loudness and sound spectrum.

Improvements in the design of linear diffusers for photodynamic therapy

The angular radiance distribution of several linear diffusers used for photodynamic therapy (PDT) was measured. The forward scattering found previously was not observed for these designs. The improved isotropy leads to a better agreement between intended treatment site and actual maximum of the fluence rate profile when the linear diffuser is used in a hollow, cylindrical organ.

Arabidopsis gynoecium structure in the wild type and in ettin mutants

The gynoecium is the female reproductive structure of flowering plants. Here we present a description of the Arabidopsis thaliana gynoecium at anthesis. The cylindrical organ can be broken down into three longitudinal regions arranged in an apical-basal order: stigma, style, and ovary. Each region can be distinguished histologically and morphologically. The transmitting (pollination) tract is axially positioned along the center of the gynoecium and spans stigma, style and ovary. Histochemistry, scanning electron microscopy and a style-specific reporter gene are used to compare the wild-type pattern of gynoecium cell types and regions, with patterns formed in gynoecia of individuals homozygous for a series of allelic mutations at the ETTIN locus. ettin gynoecia show morphological and histological alterations that appear to result from the merging of apical and basal regions and the development of abaxial into adaxial tissues. These developmental abnormalities result in a reduction of the ovary region, an expansion of the stylar and stigmatic regions, and the abaxial (outward) proliferation of transmitting tract tissue. The alterations in the mutants can be interpreted as resulting from misspecifications of position along the longitudinal and transverse axes during gynoecium development. The results suggest that early patterning events underlie wild-type gynoecium development, and that ETT functions during this early programming.

Reorganization of cortical microtubules and cellulose deposition during leaf formation in Graptopetalum paraguayense

In the "regeneration" of a shoot from a leaf of the succulent, Graptopetalum paraguayense E. Walther the first new organs are leaf primordia. The original arrangement of cellulose microfibrils and of microtubules (MTs) in the epidermis of the leaf-forming site is one of parallel, straight lines. In the new primordium both structures still have a congruent arrangement but it is roughly in the form of concentric circles that surround the new cylindrical organ. The regions which undergo the greatest shift in orientation (90°) were studied in detail. Departures from the original cellulose alignment are detected in changes in the polarized-light image. Departures from the original cortical MT arrangement are detected using electron microscopy. The over-all reorganization of the MT pattern is followed by the tally of MT profiles, the various regions being studied in two perpendicular planes of section. This corrects for the difference in efficiency in counting transverse versus longitudinal profiles of MTs. Reorientation takes place sporadically, cell by cell, for both the cellulose microfibrils and the MTs, indicating a coordinated reorientation of the two structures. That MTs and cellulose microfibrils reorient jointly in individual cells was shown by reconstruction of the arrays of cortical MTs in paradermal sections of individual cells whose recent change in the orientation of cellulose deposition had been detected with polarized light. Closeness of the two alignments was also indicated by images where the MT and microfibril alignments co-varied within a single cell. The change-over in alignment of the MTs appears to involve stages where arrays of contrasting orientation co-exist to give a criss-cross image. During this critical reorganization, the frequency of the MTs is high. It falls during subsequent enlargement of the organ. It was found that the rearrangement of the cortical MTs to approximate a series of concentric circles on the residual meristem occurred before the emergence of leaf primordia. Through their apparent influence on microfibril alignments, the changes in MT disposition, described here, have the potential to generate major biophysical changes that accompany organogenesis.

Absorption Cross Section of a Pipe Organ Due to Resonant Vibration of the Pipe Walls

The sound absorption by a rank of organ pipes from a sound field arises chiefly from air-column resonance losses plus boundary-layer dissipation at the external surfaces of the pipes. These processes have been discussed elsewhere [A. H. Benade, J. Acoust. Soc. Am. 38, 780–798 (1965) and 41, 32–38 (1967)]. The pipe walls themselves can vibrate when driven by the sound field, so that there is a further absorption of energy. The present report shows (on the basis of measured elastic and damping constants of pipe metal) that the wall-vibration resonance-absorption cross section for a complete rank of cylindrical organ pipes is negligible, being less than 1 cm2 at 62 Hz, falling to less than 0.05 cm2 at 2000 Hz. For elliptical pipes, the absorption can be a hundred fold larger, but it is still negligible as compared with the other absorption processes. It is also shown that the reradiation due to wall vibrations is so small as to justify the assumption, on which an earlier calculation of external surface absorption was based, that the pipes scatter as though they are essentially rigid.

HYPERPOLARIZING ACTION POTENTIALS RECORDED FROM THE OESOPHAGUS OF ASCARIS LUMBRICOIDES.

THE œsophagus of Ascaris is a stout cylindrical organ up to 7 mm in length and more than 1 mm in diameter, which in fresh preparations is often seen to contract rhythmically. Vigorous contractions are also elicited by brief electric pulses applied directly to its surface.

Effect of Wall Material on Organ-Pipe Tone—An Evaluation of Some Earlier Experiments

Dayton C. Miller has described experiments on a double-wall organ pipe of rectangular cross section in which the space between the wails could be filled with water, producing substantial alterations in pitch and tone [Science 29, 161 (1909)]. These experiments have been quoted by Miller and others as demonstrating the influence of the wall material on the tone quality of woodwind instruments. Calculations of the elastic deformations to be expected under internal pressure show that Miller's results are due to the rectangular cross section of his pipe and would be absent for one of circular cross section. This result was verified in this laboratory by constructing a double-wall cylindrical organ pipe, for which no measurable changes in tone were produced when the space between the walls was filled with water. This result is also verified by the experiments of Boner and Newman on cylindrical organ pipes [J. Acoust. Soc. Am. 12, 83 (1940)]. The small differences in pitch and quality among the thinner pipes noted by these authors can be explained by assuming the pipes to have a slightly elliptical cross section. For cylindrical organ pipes of reasonable wall rigidity, the steady-state tone quality should not depend on the wall material.

Notes on Zenker's Organs in the Ostracod Candona

MaLe ostracods of Candona and other genera of the family Cyprididae have paired ejaculatory apparatus, commonly called Zenker's organs. These distinctive, voluminous organs lie in the posterodorsal part of the body, one on each side (fig. 8). Each Zenker's organ consists of a central tube, several wreaths of chitinous spines, numerous tiny muscles, and a surrounding cylinder of epithelial tissue. The central tube is composed of epithelium reinforced with numerous hollow chitin rings, closely spaced 'but allowing the organ to be shortened by contraction of the muscles. Several wreaths of radiating chitin spines are attached to the central tube and laced together by an intricate set of very small muscles. The front and rear wreaths, which form the two ends of the cylindrical organ, are more complex than the others and have funnel-shaped indentations. The central tube is part of the vas deferens. In copulation, the muscles rhythmically contract in sequence to draw the spines together, shorten the central tube, and force the very long spermatozoa through the organ and out of the penis. The male sex system, of which the Zenker's organs are integral parts, is rather complex in cypridid ostracods. Each half of the system is complete and lies on one side of the median plane; it is approximately a mirror image of the half on the opposite side, but is in no way connectecd to it. To show the relationship of Zenker's organ to other male sex organs, one half of the system is here described briefly. The four testes lie in the hypodermis, a thin flap of tissue which spreads out from the side of the body and lines the valve. They are parallel -and, from their syncytia in the posterior part of the hypodermis, curve downward, forward, and upward (fig. 9). At their entrance into the body, the testes unite to form a vas deferens, which has a devious circuit. The vas deferens re-enters the hypodermis at the side of the forehead, curves parallel to the free edge of the valve, and ends 'blindly in the posterodorsal region. Upon reaching the blind end, spermatozoa reverse their direction and retrace their route to the ventral region where they enter a second branch of the vas deferens, which parallels the first along the anterior margin of the hypodermis (fig. 9). The vas deferens then extends to the rear of the body, loops back and forth a few times, encircles the Zenker's organ, and enlarges to form a seminal vesicle. Zenker's organ lies immediately behind the seminal vesicle (figs. 8-9). It surrounds a short section of the vas deferens. From the rear of the organ a very narrow tube leads into the intricate penis, in which it makes a more or less S-shaped circuit, marked by several enlargements. It terminates at the tip of the inner lobe of the large penis (fig. 9).